bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2024–10–20
95 papers selected by
Viktor Korolchuk, Newcastle University
  1. Mitophagy as a guardian against cellular aging.
  2. Autophagy, aging, and age-related neurodegeneration.
  3. Clustering lysosomes around the MTOC: a promising strategy for SNCA/alpha-synuclein breakdown leading to parkinson disease treatment.
  4. Autophagy adaptors mediate Parkin-dependent mitophagy by forming sheet-like liquid condensates.
  5. Targeting selective autophagy in CNS disorders by small-molecule compounds.
  6. Interactors and neighbors of ULK1 complex members.
  7. Polysiloxane-Based Fluorescent Probes for Visualizing pH and Thiocyanate during Mitochondrial Autophagy.
  8. USP7 protects TFEB from proteasome-mediated degradation.
  9. RhoBTB3 Functions as a Novel Regulator of Autophagy by Suppressing AMBRA1 Stability.
  10. Transcription factor EB, a promising therapeutic target in cardiovascular disease.
  11. Functional Relationships between L1CAM, LC3, ATG12, and Aβ.
  12. Autophagy and cancer therapy.
  13. The neurotrophic factor MANF regulates autophagy and lysosome function to promote proteostasis in Caenorhabditis elegans.
  14. A novel ER stress regulator ARL6IP5 induces reticulophagy to ameliorate the prion burden.
  15. A TBK1-independent primordial function of STING in lysosomal biogenesis.
  16. The autophagy initiation factor ATG13 mRNA is stabilized by the RNA-binding protein YBX3.
  17. Enhancement of Autophagy in Macrophages via the p120-Catenin-Mediated mTOR Signaling Pathway.
  18. Mitochondria-giant lipid droplet proximity and autophagy suppression in nitrogen-depleted oleaginous yeast Lipomyces starkeyi cells.
  19. Mitophagy-associated programmed neuronal death and neuroinflammation.
  20. AKT2-mediated lysosomal dysfunction promotes secretory autophagy in retinal pigment epithelium (RPE) cells.
  21. Reduced expression of SMAD7 and consequent reduction of autophagy promotes endometrial stromal-myofibroblast transition and fibrosis.
  22. CLC2 (clathrin light chain 2)-ATG8h/ATG8i interactions connect clathrin-mediated endocytosis (CME) and the autophagy pathway.
  23. Chaperone-Mediated Autophagy Regulates Hypoxic Pathology in Cardiomyocytes.
  24. The role of SIRT1 in autophagy and drug resistance: unveiling new targets and potential biomarkers in cancer therapy.
  25. Autophagy in oral cancer: Promises and challenges (Review).
  26. Acquisition of neurodegenerative features in isogenic OPTN(E50K) human stem cell-derived retinal ganglion cells associated with autophagy disruption and mTORC1 signaling reduction.
  27. An update on autophagy disorders.
  28. Natural Autophagy Activators to Fight Age-Related Diseases.
  29. Thyroid Hormone-Mediated Selective Autophagy and Its Implications in Countering Metabolic Dysfunction-Associated Steatotic Liver Disease.
  30. Reticulophagy and viral infection.
  31. Copper aggravated synaptic damage after traumatic brain injury by downregulating BNIP3-mediated mitophagy.
  32. Synergistic Role of Amino Acids in Enhancing mTOR Activation Through Lysosome Positioning.
  33. Harnessing luciferase chemistry in regulated cell death modalities and autophagy: overview and perspectives.
  34. MicroRNA-451 from Human Umbilical Cord-Derived Mesenchymal Stem Cell Exosomes Inhibits Alveolar Macrophage Autophagy via Tuberous Sclerosis Complex 1/Mammalian Target of Rapamycin Pathway to Attenuate Burn-Induced Acute Lung Injury in Rats.
  35. Coronavirus M protein promotes mitophagy over virophagy by recruiting PDPK1 to phosphorylate SQSTM1 at T138.
  36. Enhancing CNS mitophagy: drug development and disease-relevant models.
  37. Unraveling autophagic imbalances and therapeutic insights in Mecp2-deficient models.
  38. PLD3 and PLD4 synthesize S,S-BMP, a key phospholipid enabling lipid degradation in lysosomes.
  39. Water-dispersible fluorescent COFs disturb lysosomal autophagy to boost cascading enzymatic chemodynamic-starvation therapy.
  40. Regualtion of LAMTOR1 by Oxidative Stress in Retinal Pigment Epithelium: Implications for Age-Related Macular Degeneration Pathogenesis.
  41. Rapid turnover of CTLA4 is associated with a complex architecture of reversible ubiquitylation.
  42. The role of autophagy in pancreatic diseases.
  43. Autophagy is required for mammary tumor recurrence by promoting dormant tumor cell survival following therapy.
  44. Should it stay or should it go: gap junction protein GJA1/Cx43 conveys damaged lysosomes to the cell periphery to potentiate exocytosis.
  45. Regulation of the NLRP3 inflammasome by autophagy and mitophagy.
  46. AZD8055 Is More Effective Than Rapamycin in Inhibiting Proliferation and Promoting Mitochondrial Clearance in Erythroid Differentiation.
  47. Autophagy and inflammasome activation are associated with poor response to FLT3 inhibitors in patients with FLT3-ITD acute myeloid leukemia.
  48. Glutamine metabolism modulates microglial NLRP3 inflammasome activity through mitophagy in Alzheimer's disease.
  49. Evidence for the potential role of m6A modification in regulating autophagy in models of amyotrophic lateral sclerosis.
  50. Autophagy is a promising process for linking inflammation and redox homeostasis in Down syndrome.
  51. Effect of natural products on host cell autophagy induced by Influenza A virus infection.
  52. Small Molecules Inducing Autophagic Degradation of Expanded Polyglutamine Protein through Interaction with Both Mutant ATXN3 and LC3.
  53. Blockade of mTORC1 via Rapamycin Suppresses 27-Hydroxycholestrol-Induced Inflammatory Responses.
  54. Trophoblast-specific overexpression of adiponectin receptor 2 causes fetal growth restriction in pregnant mice.
  55. Deficiency of parkin causes neurodegeneration and accumulation of pathological α-synuclein in monkey models.
  56. A supramolecular fluorescence probe that simultaneously responds to viscosity and G-quadruplex for autophagy detection.
  57. AKT/mTOR-mediated autophagic signaling is associated with TCDD-induced cleft palate.
  58. Circular RNA hsa_circ_0081343 modulates trophoblast autophagy through Rbm8a nuclear translocation.
  59. HKDC1 promotes autophagy and proliferation in pancreatic adenocarcinoma through interaction with PARP1 and poly(ADP-ribosyl)ation.
  60. GLS2 reduces the occurrence of epilepsy by affecting mitophagy function in mouse hippocampal neurons.
  61. Ceramide lowering rescues respiratory defects in a Drosophila model of acid sphingomyelinase deficiency.
  62. Hyperbaric Treatment Stimulates Chaperone-Mediated Macroautophagy and Autophagy in the Liver Cells of Healthy Female Rats.
  63. Spatially Selective Self-Amplified Imaging of Chemotherapy-Induced Cancer Senescence via Reversal of Impaired Ferritinophagy.
  64. Methylarginine targeting chimeras for lysosomal degradation of intracellular proteins.
  65. Irisin suppresses PDGF-BB-induced proliferation of vascular smooth muscle cells in vitro by activating AMPK/mTOR-mediated autophagy.
  66. S100A8 knockdown activates the PI3K/AKT signaling pathway to inhibit microglial autophagy and improve cognitive impairment mediated by chronic sleep deprivation.
  67. Proteostasis and Its Role in Disease Development.
  68. Formononetin triggers ferroptosis in triple-negative breast cancer cells by regulating the mTORC1/SREBP1/SCD1 pathway.
  69. Histone deacetylase 6 inhibition promotes microtubule acetylation and facilitates autophagosome-lysosome fusion in dystrophin-deficient mdx mice.
  70. Plasma membrane repair defect in Alzheimer's disease neurons is driven by the reduced dysferlin expression.
  71. Updated insights into the NLRP3 inflammasome in postoperative cognitive dysfunction: emerging mechanisms and treatments.
  72. Tip60-mediated Rheb acetylation links palmitic acid with mTORC1 activation and insulin resistance.
  73. The Antidepressant Drug Amitriptyline Affects Human SH-SY5Y Neuroblastoma Cell Proliferation and Modulates Autophagy.
  74. Involvement of autophagy and gut dysbiosis in ambient particulate matter-induced colonic inflammation.
  75. Uric Acid: A Biomarker and Pathogenic Factor of Affective Disorders and Neurodegenerative Diseases.
  76. Oncological Aspects of Lysosomal Storage Diseases.
  77. Crossing the border: Replication fork adducts move to lysosomes for autophagic repair.
  78. Modulating autophagy to boost the antitumor efficacy of TROP2-directed antibody-drug conjugate in pancreatic cancer.
  79. Treatment of polyethylene microplastics degraded by ultraviolet light irradiation causes lysosome-deregulated cell death.
  80. Et tu, Brute? TFEB promotes virus replication before being cleaved by a viral protease.
  81. PTB Regulates Keloid Fibroblast Migration and Proliferation Through Autophagy.
  82. Bidirectional modulation of extracellular vesicle-autophagy axis in acute lung injury: Molecular mechanisms and therapeutic implications.
  83. Tetrahydroxy stilbene glucoside promotes mitophagy and ameliorates neuronal injury after cerebral ischemia reperfusion via promoting USP10 mediated YBX1 stability.
  84. Txnip promotes autophagic apoptosis in diabetic cardiomyopathy by upregulating FoxO1 and its acetylation.
  85. The Role of Sirtuin 1 in Ageing and Neurodegenerative Disease: A Molecular Perspective.
  86. "β-glucan signalling stimulates NOX-2 dependent autophagy and LC-3 associated autophagy (LAP) pathway".
  87. MC-LR disrupts dopamine synthesis in the substantia nigra of midbrain by enhancing the chaperone-mediated autophagy pathway through direct binding to ERK2.
  88. Dual-color Correlative Light and Electron Microscopy for the Visualization of Interactions between Mitochondria and Lysosomes.
  89. Neuropathology in an α-synuclein preformed fibril mouse model occurs independent of the Parkinson's disease-linked lysosomal ATP13A2 protein.
  90. Melatonin ameliorates chronic sleep deprivation against memory encoding vulnerability: Involvement of synapse regulation via the mitochondrial-dependent redox homeostasis-induced autophagy inhibition.
  91. Editorial: Autophagy: unveiling the mechanisms and implications in health and disease.
  92. miR‑1343‑3p inhibits autophagy by directly targeting ATG7 in multiple myeloma cells.
  93. SHCBP1 promotes cisplatin resistance of ovarian cancer through AKT/mTOR/Autophagy pathway.
  94. Trehalose Attenuates In Vitro Neurotoxicity of 6-Hydroxydopamine by Reducing Oxidative Stress and Activation of MAPK/AMPK Signaling Pathways.
  95. UCF101 Rescues against Diabetes-Evoked Cardiac Remodeling and Contractile Anomalies through AMPK-Mediated Induction of Mitophagy.
  1. Autophagy. 2024 Oct 14. 1-3
    Mitophagy as a guardian against cellular aging.
    Tetsushi Kataura, Niall Wilson, Gailing Ma, Viktor I Korolchuk.
      Mitophagy, the selective autophagic clearance of damaged mitochondria, is considered vital for maintaining mitochondrial quality and cellular homeostasis; however, its molecular mechanisms, particularly under basal conditions, and its role in cellular physiology remain poorly characterized. We recently demonstrated that basal mitophagy is a key feature of primary human cells and is downregulated by immortalization, suggesting its dependence on the primary cell state. Mechanistically, we demonstrated that the PINK1-PRKN-SQSTM1 pathway regulates basal mitophagy, with SQSTM1 sensing superoxide-enriched mitochondria through its redox-sensitive cysteine residues, which mediate SQSTM1 oligomerization and mitophagy activation. We developed STOCK1N-57534, a small molecule that targets and promotes this SQSTM1 activation mechanism. Treatment with STOCK1N-57534 reactivates mitophagy downregulated in senescent and naturally aged donor-derived primary cells, improving cellular senescence(-like) phenotypes. Our findings highlight that basal mitophagy is protective against cellular senescence and aging, positioning its pharmacological reactivation as a promising anti-aging strategy.Abbreviation: IR: ionizing radiation; ROS: reactive oxygen species; SARs: selective autophagy receptors.
    Keywords:  Aging; SQSTM1/p62; autophagy; mitochondria; mitophagy; senescence
    DOI:  https://doi.org/10.1080/15548627.2024.2414461
  2. Neuron. 2024 Oct 08. pii: S0896-6273(24)00663-9. [Epub ahead of print]
    Autophagy, aging, and age-related neurodegeneration.
    Jennifer E Palmer, Niall Wilson, Sung Min Son, Pawel Obrocki, Lidia Wrobel, Matea Rob, Michael Takla, Viktor I Korolchuk, David C Rubinsztein.
      Autophagy is a conserved mechanism that degrades damaged or superfluous cellular contents and enables nutrient recycling under starvation conditions. Many neurodegeneration-associated proteins are autophagy substrates, and autophagy upregulation ameliorates disease in many animal models of neurodegeneration by enhancing the clearance of toxic proteins, proinflammatory molecules, and dysfunctional organelles. Autophagy inhibition also induces neuronal and glial senescence, a phenomenon that occurs with increasing age in non-diseased brains as well as in response to neurodegeneration-associated stresses. However, aging and many neurodegeneration-associated proteins and mutations impair autophagy. This creates a potentially detrimental feedback loop whereby the accumulation of these disease-associated proteins impairs their autophagic clearance, facilitating their further accumulation and aggregation. Thus, understanding how autophagy interacts with aging, senescence, and neurodegenerative diseases in a temporal, cellular, and genetic context is important for the future clinical application of autophagy-modulating therapies in aging and neurodegeneration.
    Keywords:  Alzheimer’s disease; Huntington’s disease; Parkinson’s disease; aging; autophagy; frontotemporal dementia; motor neuron disease; neurodegeneration; senescence
    DOI:  https://doi.org/10.1016/j.neuron.2024.09.015
  3. Autophagy. 2024 Oct 14. 1-2
    Clustering lysosomes around the MTOC: a promising strategy for SNCA/alpha-synuclein breakdown leading to parkinson disease treatment.
    Yukiko Sasazawa, Yuki Date, Nobutaka Hattori, Shinji Saiki.
      Macroautophagy/autophagy maintains cellular homeostasis by degrading cytoplasmic components and its disruption is linked to Parkinson disease (PD), which is characterized by dopamine depletion and the accumulation of SNCA/α-synuclein aggregates in neurons. Therefore, activation of autophagy is considered a therapeutic strategy for PD; however, autophagy inducers have not yet been developed as therapeutic drugs because they are involved in a wide range of signaling pathways. Here, we focused on the lysosomal clustering around the microtubule-organizing center (MTOC) that can regulate the process of autophagosome-lysosome fusion, the final step of autophagy, and examined how lysosomal clustering affects protein degradation through autophagy. Our study identified six compounds from a high-content screen of 1,200 clinically approved drugs that induce both lysosomal clustering and autophagy. Notably, albendazole reduced SNCA aggregates in a PD model by lysosomal clustering and autophagy. These findings suggest that targeting lysosomal clustering could offer new therapeutic insights for PD.
    Keywords:  Alpha-synuclein; Parkinson disease; autophagy; lysosomal clustering; lysosomal trafficking
    DOI:  https://doi.org/10.1080/15548627.2024.2413295
  4. EMBO J. 2024 Oct 17.
    Autophagy adaptors mediate Parkin-dependent mitophagy by forming sheet-like liquid condensates.
    Zi Yang, Saori R Yoshii, Yuji Sakai, Jing Zhang, Haruka Chino, Roland L Knorr, Noboru Mizushima.
      During PINK1- and Parkin-mediated mitophagy, autophagy adaptors are recruited to damaged mitochondria to promote their selective degradation. Autophagy adaptors such as optineurin (OPTN) and NDP52 facilitate mitophagy by recruiting the autophagy-initiation machinery, and assisting engulfment of damaged mitochondria through binding to ubiquitinated mitochondrial proteins and autophagosomal ATG8 family proteins. Here, we demonstrate that OPTN and NDP52 form sheet-like phase-separated condensates with liquid-like properties on the surface of ubiquitinated mitochondria. The dynamic and liquid-like nature of OPTN condensates is important for mitophagy activity, because reducing the fluidity of OPTN-ubiquitin condensates suppresses the recruitment of ATG9 vesicles and impairs mitophagy. Based on these results, we propose a dynamic liquid-like, rather than a stoichiometric, model of autophagy adaptors to explain the interactions between autophagic membranes (i.e., ATG9 vesicles and isolation membranes) and mitochondrial membranes during Parkin-mediated mitophagy. This model underscores the importance of liquid-liquid phase separation in facilitating membrane-membrane contacts, likely through the generation of capillary forces.
    Keywords:  Autophagy; Liquid–Liquid Phase Separation; Mitophagy; Optineurin; Wetting
    DOI:  https://doi.org/10.1038/s44318-024-00272-5
  5. Pharmacol Ther. 2024 Oct 12. pii: S0163-7258(24)00149-9. [Epub ahead of print] 108729
    Targeting selective autophagy in CNS disorders by small-molecule compounds.
    Yanrong Zheng, Zhuchen Zhou, Mengting Liu, Zhong Chen.
      Autophagy functions as the primary cellular mechanism for clearing unwanted intracellular contents. Emerging evidence suggests that the selective elimination of intracellular organelles through autophagy, compared to the increased bulk autophagic flux, is crucial for the pathological progression of central nervous system (CNS) disorders. Notably, autophagic removal of mitochondria, known as mitophagy, is well-understood in an unhealthy brain. Accumulated data indicate that selective autophagy of other substrates, including protein aggregates, liposomes, and endoplasmic reticulum, plays distinctive roles in various pathological stages. Despite variations in substrates, the molecular mechanisms governing selective autophagy can be broadly categorized into two types: ubiquitin-dependent and -independent pathways, both of which can be subjected to regulation by small-molecule compounds. Notably, natural products provide the remarkable possibility for future structural optimization to regulate the highly selective autophagic clearance of diverse substrates. In this context, we emphasize the selectivity of autophagy in regulating CNS disorders and provide an overview of chemical compounds capable of modulating selective autophagy in these disorders, along with the underlying mechanisms. Further exploration of the functions of these compounds will in turn advance our understanding of autophagic contributions to brain disorders and illuminate precise therapeutic strategies for these diseases.
    Keywords:  Autophagy; CNS disorders; Mitophagy; Natural products; Selective autophagy; Small-molecule compounds
    DOI:  https://doi.org/10.1016/j.pharmthera.2024.108729
  6. Autophagy. 2024 Oct 14. 1-3
    Interactors and neighbors of ULK1 complex members.
    Devanarayanan Siva Sankar, Joern Dengjel.
      The ULK1 kinase complex plays a crucial role in autophagosome biogenesis. To identify interactors or regulators of ULK1 complex assembly influencing autophagosome biogenesis, we performed an interaction proteomics screen. Employing both affinity purification and proximity labeling of N- and C-terminal tagged fusion proteins coupled to quantitative mass spectrometry, we identified 317 high-confidence interactors or neighbors of the four ULK1 complex members, including both member-specific and common interactors. Interactions with selective macroautophagy/autophagy receptors indicate the activation of selective autophagy pathways by 90 min of nutrient starvation. Focusing on the ULK1 effector protein BAG2, a common interactor identified by both approaches, we highlight that ULK1 phosphorylates BAG2, supporting the localization of the scaffold and autophagy inducer AMBRA1 to the ER, thereby positively regulating autophagy initiation.Abbreviation: AMBRA1: autophagy and beclin 1 regulator 1; ATG: autophagy related; ER: endoplasmic reticulum; HA: hemagglutinin; KD: knockdown; KO: knockout; MS: mass spectrometry; PTM: posttranslational modification; RB1CC1/FIP200: RB1 inducible coiled-coil 1; SQSTM1/p62: sequestosome 1; ULK1: unc-51 like autophagy activating kinase 1; WIPI2: WD repeat domain, phosphoinositide interacting 2.
    Keywords:  Affinity purification; kinase; mass spectrometry; miniturbo; proteomics; proximity labeling
    DOI:  https://doi.org/10.1080/15548627.2024.2414386
  7. Anal Chem. 2024 Oct 10.
    Polysiloxane-Based Fluorescent Probes for Visualizing pH and Thiocyanate during Mitochondrial Autophagy.
    Yujing Zuo, Ying Lan, Zhiming Gou, Yanfu Chai, Mei Yan.
      Mitochondrial autophagy, known as mitophagy, is a vital cellular process that involves the selective degradation of damaged or dysfunctional mitochondria through autophagy, which is critical to the functional integrity of the entire mitochondrial network and determines the survival and death of cells. An abnormal pH may lead to an imbalance in mitochondrial homeostasis and the occurrence of mitochondrial autophagic acidification and dysfunction. SCN- is also an important anion in cellular metabolism, and its abnormal concentration may lead to mitochondrial damage. However, so far, there are few reports on the simultaneous realization of pH and SCN- detection in mitochondria. Therefore, to complement the blank in this area, we developed the polysiloxane-based fluorescent probe P0-CMN that is capable of simultaneously visualizing pH and SCN- fluctuation levels in mitochondria. The probe P0-CMN has the desired mitochondrial-targeting properties and sensitivity to pH and SCN-. It is able to simultaneously monitor pH and SCN- changes in mitochondria in a dual-channel mode. In addition, probe P0-CMN can visualize pH changes during mitochondrial autophagy. This work provides an effective strategy for the design of dual-responsive fluorescent probes and further broadens the application of polysiloxane fluorescent materials.
    DOI:  https://doi.org/10.1021/acs.analchem.4c03499
  8. Cell Rep. 2024 Oct 15. pii: S2211-1247(24)01223-3. [Epub ahead of print]43(11): 114872
    USP7 protects TFEB from proteasome-mediated degradation.
    Swati Keshri, Mariella Vicinanza, Michael Takla, David C Rubinsztein.
      The transcription factor EB (TFEB) is a master regulator of lysosomal biogenesis and autophagy. We identify a distinct nuclear interactome of TFEB, with ubiquitin-specific protease 7 (USP7) emerging as a key post-translational modulator of TFEB. Genetic depletion and inhibition of USP7 reveal its critical role in preserving TFEB stability within both nuclear and cytoplasmic compartments. Specifically, USP7 is identified as the deubiquitinase responsible for removing the K48-linked polyubiquitination signal from TFEB at lysine residues K116, K264, and K274, thereby preventing its proteasomal degradation. Functional assays demonstrate the involvement of USP7 in preserving TFEB-mediated transcriptional responses to nutrient deprivation while also modulating autophagy flux and lysosome biogenesis. As USP7 is a deubiquitinase that protects TFEB from proteasomal degradation, these findings provide the foundation for therapeutic targeting of the USP7-TFEB axis in conditions characterized by TFEB dysregulation and metabolic abnormalities, particularly in certain cancers.
    Keywords:  CP: Cell biology; CP: Molecular biology; TFEB; USP7; autophagy; lysosomal biogenesis; post-translational modifications; proteasomal degradation; ubiquitination
    DOI:  https://doi.org/10.1016/j.celrep.2024.114872
  9. Cells. 2024 Oct 07. pii: 1659. [Epub ahead of print]13(19):
    RhoBTB3 Functions as a Novel Regulator of Autophagy by Suppressing AMBRA1 Stability.
    Kyungho Kim, Dong-Gun Kim, Youn-Jae Kim.
      Autophagy is essential for cell survival and cellular homeostasis under various stress conditions. Therefore, autophagy dysfunction is associated with the pathogenesis of various human diseases. We explored the regulatory role of RhoBTB3 in autophagy and its interaction with activating molecules in AMBRA1. RhoBTB3 deficiency was found to induce autophagy, while its overexpression inhibited autophagy induction. Through immunoprecipitation and mass spectrometry, AMBRA1 was identified as a substrate of RhoBTB3. The study revealed that RhoBTB3 regulates AMBRA1 stability by influencing its protein levels without affecting its mRNA levels. RhoBTB3 induced the ubiquitination of AMBRA1, leading to proteasome-mediated degradation, with the ubiquitination occurring at K45 on AMBRA1 through a K27-linked ubiquitin chain. The knockdown of AMBRA1 blocked RhoBTB3 knockdown-induced autophagy, indicating the dependency of autophagy on AMBRA1. Thus, RhoBTB3 negatively regulates autophagy by mediating AMBRA1 ubiquitination and degradation, suggesting RhoBTB3 as a potential therapeutic target for autophagy-related diseases.
    Keywords:  AMBRA1; RhoBTB3; autophagy
    DOI:  https://doi.org/10.3390/cells13191659
  10. PeerJ. 2024 ;12 e18209
    Transcription factor EB, a promising therapeutic target in cardiovascular disease.
    Xin Yan, Li Yang, Xiaolei Fu, Xin Luo, Chengming Wang, Qiu Ping Xie, Fan OuYang.
      Cardiovascular disease (CVD) remains the major cause of morbidity and mortality around the world. Transcription factor EB (TFEB) is a master regulator of lysosome biogenesis and autophagy. Emerging studies revealed that TFEB also mediates cellular adaptation responses to various stimuli, such as mitochondrial dysfunction, pathogen infection and metabolic toxin. Based on its significant capability to modulate the autophagy-lysosome process (ALP), TFEB plays a critical role in the development of CVD. In this review, we briefly summarize that TFEB regulates cardiac dysfunction mainly through ameliorating lysosomal and mitochondrial dysfunction and reducing inflammation.
    Keywords:  Autophagic flux; Cardiovascular disease; Lysosome; TFEB
    DOI:  https://doi.org/10.7717/peerj.18209
  11. Int J Mol Sci. 2024 Oct 09. pii: 10829. [Epub ahead of print]25(19):
    Functional Relationships between L1CAM, LC3, ATG12, and Aβ.
    Gabriele Loers, Ute Bork, Melitta Schachner.
      Abnormal protein accumulations in the brain are linked to aging and the pathogenesis of dementia of various types, including Alzheimer's disease. These accumulations can be reduced by cell indigenous mechanisms. Among these is autophagy, whereby proteins are transferred to lysosomes for degradation. Autophagic dysfunction hampers the elimination of pathogenic protein aggregations that contribute to cell death. We had observed that the adhesion molecule L1 interacts with microtubule-associated protein 1 light-chain 3 (LC3), which is needed for autophagy substrate selection. L1 increases cell survival in an LC3-dependent manner via its extracellular LC3 interacting region (LIR). L1 also interacts with Aβ and reduces the Aβ plaque load in an AD model mouse. Based on these results, we investigated whether L1 could contribute to autophagy of aggregated Aβ and its clearance. We here show that L1 interacts with autophagy-related protein 12 (ATG12) via its LIR domain, whereas interaction with ubiquitin-binding protein p62/SQSTM1 does not depend on LIR. Aβ, bound to L1, is carried to the autophagosome leading to Aβ elimination. Showing that the mitophagy-related L1-70 fragment is ubiquitinated, we expect that the p62/SQSTM1 pathway also contributes to Aβ elimination. We propose that enhancing L1 functions may contribute to therapy in humans.
    Keywords:  Alzheimer’s disease; Aβ; L1CAM; LC3; LIR; autophagy
    DOI:  https://doi.org/10.3390/ijms251910829
  12. Cancer Lett. 2024 Oct 10. pii: S0304-3835(24)00680-3. [Epub ahead of print] 217285
    Autophagy and cancer therapy.
    Julio M Pimentel, Jun Ying Zhou, Gen Sheng Wu.
      Autophagy is an intracellular degradation process that sequesters cytoplasmic components in double-membrane vesicles known as autophagosomes, which are degraded upon fusion with lysosomes. This pathway maintains the integrity of proteins and organelles while providing energy and nutrients to cells, particularly under nutrient deprivation. Deregulation of autophagy can cause genomic instability, low protein quality, and DNA damage, all of which can contribute to cancer. Autophagy can also be overactivated in cancer cells to aid in cancer cell survival and drug resistance. Emerging evidence indicates that autophagy has functions beyond cargo degradation, including roles in tumor immunity and cancer stem cell survival. Additionally, autophagy can also influence the tumor microenvironment. This feature warrants further investigation of the role of autophagy in cancer, in which autophagy manipulation can improve cancer therapies, including cancer immunotherapy. This review discusses recent findings on the regulation of autophagy and its role in cancer therapy and drug resistance.
    Keywords:  autophagy; cancer; resistance; therapy
    DOI:  https://doi.org/10.1016/j.canlet.2024.217285
  13. Proc Natl Acad Sci U S A. 2024 Oct 22. 121(43): e2403906121
    The neurotrophic factor MANF regulates autophagy and lysosome function to promote proteostasis in Caenorhabditis elegans.
    Shane K B Taylor, Jessica H Hartman, Bhagwati P Gupta.
      The conserved mesencephalic astrocyte-derived neurotrophic factor (MANF) is known for protecting dopaminergic neurons and functioning in various other tissues. Previously, we showed that Caenorhabditis elegans manf-1 null mutants exhibit defects such as increased endoplasmic reticulum (ER) stress, dopaminergic neurodegeneration, and abnormal protein aggregation. These findings suggest an essential role for MANF in cellular processes. However, the mechanisms by which intracellular and extracellular MANF regulate broader cellular functions remain unclear. We report a unique mechanism of action for MANF-1 that involves the transcription factor HLH-30/TFEB-mediated signaling to regulate autophagy and lysosomal function. Multiple transgenic strains overexpressing MANF-1 showed extended lifespan of animals, reduced protein aggregation, and improved neuronal survival. Using fluorescently tagged MANF-1, we observed tissue-specific localization of the protein, which was dependent on the ER retention signal. Further subcellular analysis showed that MANF-1 localizes within cells to the lysosomes and utilizes the endosomal pathway. Consistent with the lysosomal localization, our transcriptomic study of MANF-1 and analyses of autophagy regulators demonstrated that MANF-1 promotes proteostasis by regulating autophagic flux and lysosomal activity. Collectively, our findings establish MANF as a critical regulator of stress response, proteostasis, and aging.
    Keywords:  ER stress; MANF-1; longevity; nematode; proteostasis
    DOI:  https://doi.org/10.1073/pnas.2403906121
  14. Autophagy. 2024 Oct 12.
    A novel ER stress regulator ARL6IP5 induces reticulophagy to ameliorate the prion burden.
    Kajal Kamble, Ujjwal Kumar, Harsh Aahra, Mohit Yadav, Sumnil Bhola, Sarika Gupta.
      Prion disease is a fatal and infectious neurodegenerative disorder caused by the trans-conformation conversion of PRNP/PrPC to PRNP/PrPSc. Accumulated PRNP/PrPSc-induced ER stress causes chronic unfolded protein response (UPR) activation, which is one of the fundamental steps in prion disease progression. However, the role of various ER-resident proteins in prion-induced ER stress is elusive. This study demonstrated that ARL6IP5 is compensatory upregulated in response to chronically activated UPR in the cellular prion disease model (RML-ScN2a). Furthermore, overexpression of ARL6IP5 overcomes ER stress by lowering the expression of chronically activated UPR pathway proteins. We discovered that ARL6IP5 induces reticulophagy to reduce the PRNP/PrPSc burden by releasing ER stress. Conversely, the knockdown of ARL6IP5 leads to inefficient macroautophagic/autophagic flux and elevated PRNP/PrPSc burden. Our study also uncovered that ARL6IP5-induced reticulophagy depends on Ca2+-mediated AMPK activation and can induce 3 MA-inhibited autophagic flux. The detailed mechanistic study revealed that ARL6IP5-induced reticulophagy involves interaction with soluble reticulophagy receptor CALCOCO1 and lysosomal marker LAMP1, leading to degradation in lysosomes. Here, we delineate the role of ARL6IP5 as a novel ER stress regulator and reticulophagy inducer that can effectively reduce the misfolded PRNP/PrPSc burden. Our research opens up a new avenue of selective autophagy in prion disease and represents a potential therapeutic target.
    Keywords:  Autophagy; ER stress; Reticulophagy/er-phagy; prion burden/PrPSc burden; prion disease
    DOI:  https://doi.org/10.1080/15548627.2024.2410670
  15. Mol Cell. 2024 Oct 17. pii: S1097-2765(24)00703-2. [Epub ahead of print]84(20): 3979-3996.e9
    A TBK1-independent primordial function of STING in lysosomal biogenesis.
    Bo Lv, William A Dion, Haoxiang Yang, Jinrui Xun, Do-Hyung Kim, Bokai Zhu, Jay Xiaojun Tan.
      Stimulator of interferon genes (STING) is activated in many pathophysiological conditions, leading to TBK1-dependent interferon production in higher organisms. However, primordial functions of STING independent of TBK1 are poorly understood. Here, through proteomics and bioinformatics approaches, we identify lysosomal biogenesis as an unexpected function of STING. Transcription factor EB (TFEB), an evolutionarily conserved regulator of lysosomal biogenesis and host defense, is activated by STING from multiple species, including humans, mice, and frogs. STING-mediated TFEB activation is independent of TBK1, but it requires STING trafficking and its conserved proton channel. GABARAP lipidation, stimulated by the channel of STING, is key for STING-dependent TFEB activation. STING stimulates global upregulation of TFEB-target genes, mediating lysosomal biogenesis and autophagy. TFEB supports cell survival during chronic sterile STING activation, a common condition in aging and age-related diseases. These results reveal a primordial function of STING in the biogenesis of lysosomes, essential organelles in immunity and cellular stress resistance.
    Keywords:  STING; STING channel; TBK1; TFE3; TFEB; autophagy; cGAS; chronic STING signaling; lysosome
    DOI:  https://doi.org/10.1016/j.molcel.2024.08.026
  16. FEBS Lett. 2024 Oct 16.
    The autophagy initiation factor ATG13 mRNA is stabilized by the RNA-binding protein YBX3.
    Liva Pfuhler, Silina Awad, William Skipper, Jeremy Lavietes, Thomas Sah, Kayla Ho, Radha Ivanova, Amy Cooke.
      Autophagy, a highly conserved form of cellular recycling, is essential for cellular homeostasis. Its dysregulation has been linked to neurodegenerative diseases and various cancers, including breast cancer. We set out to determine if the RNA-binding protein (RBP) YBX3 regulates autophagy mRNAs, as previous findings suggest YBX3 depletion reduces distinct autophagy transcripts. We found that YBX3 interacts with and stabilizes the mRNA of the autophagy initiation factor ATG13 in HeLa, which in turn increases ATG13 protein expression. We have shown that this requires the 3' untranslated region (UTR) of ATG13 and occurs in other human cell lines, including HEK293, HepG2, and HCT116. Together, our data suggest a novel regulatory role for YBX3 of autophagy initiation through posttranscriptional control of ATG13 mRNA stability.
    Keywords:  ATG13; RNA‐binding protein (RBP); ULK1; YBX3; autophagy initiation; posttranscriptional regulation, mRNA stability
    DOI:  https://doi.org/10.1002/1873-3468.15035
  17. J Immunol. 2024 Oct 18. pii: ji2400189. [Epub ahead of print]
    Enhancement of Autophagy in Macrophages via the p120-Catenin-Mediated mTOR Signaling Pathway.
    Suganya Kanmani, Xue-Min Song, Paulraj Kanmani, Xiao-Jing Wu, Xiao-Di Tan, Jing Liu, Ji-Ping Wang, Richard D Minshall, Guochang Hu.
      Autophagy serves as a critical regulator of immune responses in sepsis. Macrophages are vital constituents of both innate and adaptive immunity. In this study, we delved into the intricate role of p120-catenin (p120) in orchestrating autophagy in macrophages in response to endotoxin stimulation. Depletion of p120 effectively suppressed LPS-induced autophagy in both J774A.1 macrophages and murine bone marrow-derived macrophages. LPS not only elevated the interaction between p120 and L chain 3 (LC3) I/II but also facilitated the association of p120 with mammalian target of rapamycin (mTOR). p120 depletion in macrophages by small interfering RNA reduced LPS-induced dissociation of mTOR and Unc-51-like kinase 1 (ULK1), leading to an increase in the phosphorylation of ULK1. p120 depletion also enhanced LPS-triggered macrophage apoptosis, as evidenced by increased levels of cleaved caspase 3, 7-aminoactinomycin D staining, and TUNEL assay. Notably, inhibiting autophagy reversed the decrease in apoptosis caused by LPS stimulation in macrophages overexpressing p120. Additionally, the ablation of p120 inhibited autophagy and accentuated apoptosis in alveolar macrophages in LPS-challenged mice. Collectively, our findings strongly suggest that p120 plays a pivotal role in fostering autophagy while concurrently hindering apoptosis in macrophages, achieved through modulation of the mTOR/ULK1 signaling pathway in sepsis. This underscores the potential of targeting macrophage p120 as an innovative therapeutic avenue for treating inflammatory disorders.
    DOI:  https://doi.org/10.4049/jimmunol.2400189
  18. J Biochem. 2024 Oct 15. pii: mvae069. [Epub ahead of print]
    Mitochondria-giant lipid droplet proximity and autophagy suppression in nitrogen-depleted oleaginous yeast Lipomyces starkeyi cells.
    Lan Duan, Akinobu Togou, Keisuke Ohta, Koji Okamoto.
      Balancing energy production and storage is a fundamental process critical for cellular homeostasis in most eukaryotes that relies on the intimate interplay between mitochondria and lipid droplets. In the oleaginous yeast Lipomyces starkeyi under nitrogen starvation, lipid droplet forms a single giant spherical structure that is easily visible under a light microscope. Currently, how mitochondria behave in L. starkeyi cells undergoing giant lipid droplet formation remains unknown. Here we show that mitochondria transition from fragments to elongated tubules and sheet-like structures that are in close proximity to a giant lipid droplet in nitrogen-depleted L. starkeyi cells. Under the same conditions, mitochondrial degradation and autophagy are strongly suppressed, suggesting that these catabolic events are not required for giant lipid droplet formation. Conversely, carbon-depleted cells suppress mitochondrial elongation and lipid droplet expansion, whereas they promote mitochondrial degradation and autophagy. We propose a potential link of mitochondrial proximity and autophagic suppression to giant lipid droplet formation.
    Keywords:  autophagy; lipid droplet; mitochondria; oleaginous yeast
    DOI:  https://doi.org/10.1093/jb/mvae069
  19. Front Immunol. 2024 ;15 1460286
    Mitophagy-associated programmed neuronal death and neuroinflammation.
    Yanlin Zhu, Jianning Zhang, Quanjun Deng, Xin Chen.
      Mitochondria are crucial organelles that play a central role in cellular metabolism and programmed cell death in eukaryotic cells. Mitochondrial autophagy (mitophagy) is a selective process where damaged mitochondria are encapsulated and degraded through autophagic mechanisms, ensuring the maintenance of both mitochondrial and cellular homeostasis. Excessive programmed cell death in neurons can result in functional impairments following cerebral ischemia and trauma, as well as in chronic neurodegenerative diseases, leading to irreversible declines in motor and cognitive functions. Neuroinflammation, an inflammatory response of the central nervous system to factors disrupting homeostasis, is a common feature across various neurological events, including ischemic, infectious, traumatic, and neurodegenerative conditions. Emerging research suggests that regulating autophagy may offer a promising therapeutic avenue for treating certain neurological diseases. Furthermore, existing literature indicates that various small molecule autophagy regulators have been tested in animal models and are linked to neurological disease outcomes. This review explores the role of mitophagy in programmed neuronal death and its connection to neuroinflammation.
    Keywords:  apoptosis; ferroptosis; mitophagy; necroptosis; neuroinflammation; pyroptosis
    DOI:  https://doi.org/10.3389/fimmu.2024.1460286
  20. Autophagy. 2024 Oct 16. 1-2
    AKT2-mediated lysosomal dysfunction promotes secretory autophagy in retinal pigment epithelium (RPE) cells.
    Sayan Ghosh, Stacey Hose, Debasish Sinha.
      Age-related macular degeneration (AMD) is the leading cause of blindness in the elderly, with the non-neovascular or atrophic form being the most common. Current treatment options are limited, emphasizing the urgent need for new therapeutic strategies. Our key finding is that increased levels of AKT2 in the RPE cells impair lysosomal function and trigger secretory autophagy; a non-canonical macroautophagy/autophagy pathway where cellular materials are released via the plasma membrane rather than being degraded by lysosomes. We showed that this process involves a protein complex, AKT2-SYTL1-TRIM16-SNAP23, releasing factors contributing to drusen biogenesis, a clinical hallmark of AMD development. Importantly, SIRT5 can inhibit this pathway, potentially offering a protective effect. Understanding mechanisms by which this non-canonical autophagy pathway promotes extracellular waste accumulation could provide new insights into drusen biogenesis. Future therapies for atrophic AMD could focus on regulating secretory autophagy or manipulating proteins involved in this process.
    Keywords:  Atrophic age-related macular degeneration; drusen; inflammation; lysosomes; retinal pigment epithelium cells; secretory autophagy
    DOI:  https://doi.org/10.1080/15548627.2024.2413305
  21. Mol Hum Reprod. 2024 Oct 16. pii: gaae036. [Epub ahead of print]
    Reduced expression of SMAD7 and consequent reduction of autophagy promotes endometrial stromal-myofibroblast transition and fibrosis.
    Min Yong, Honggui Zhou, Yuhua Zeng, Yuqin Yao, Hongtao Zhu, Jianguo Hu.
      Abnormal autophagy and the transforming growth factor-β (TGFβ)-SMAD3/7 signaling pathway play an important role in the development of intrauterine adhesions (IUA); however, the exact underlying mechanisms remain unclear. In this study, we used IUA patient tissue and SMAD7 conditional knockout mice to detect whether SMAD7 effected IUA via regulation of autophagy and the TGFβ-SMAD3 signaling pathway. We applied a combination of techniques for detection of p-SMAD3, SMAD7, autophagy and fibrosis-related proteins, autophagic flux and analysis of the SMAD3 binding site. Endometrial tissue of patients with IUA exhibited lower expression levels of SMAD7. In endometrial stromal cells, silencing of SMAD7 inhibited autophagic flux, whereas overexpressed SMAD7 promoted autophagic flux. This SMAD7-mediated autophagic flux regulates the stromal-myofibroblast transition, and these phenotypes were regulated by the TGFβ-SMAD3 signaling pathway. SMAD3 directly binds to the 3'-untranslated region of transcription factor EB (TFEB) and inhibits its transcription. SMAD7 promoted autophagic flux by inhibiting SMAD3, thereby promoting the expression of TFEB. In SMAD7 conditional knockout mice, the endometria showed a fibrotic phenotype. Simultaneously, autophagic flux was inhibited. On administering the autophagy activator rapamycin, this endometrial fibrosis phenotype was partially reversed. The loss of SMAD7 promotes endometrial fibrosis by inhibiting autophagic flux via the TGFβ-SMAD3 pathway. Therefore, this study reveals a potential therapeutic target for IUA.
    Keywords:   SMAD7 ; IUA; TFEB; autophagy; stromal–myofibroblast transition
    DOI:  https://doi.org/10.1093/molehr/gaae036
  22. Autophagy. 2024 Oct 13.
    CLC2 (clathrin light chain 2)-ATG8h/ATG8i interactions connect clathrin-mediated endocytosis (CME) and the autophagy pathway.
    Hujiao Lan, Yating Zhao, Minjun Huang, Wenxu Wang, Jianzhong Liu.
      Extensive interconnection has been established between clathrin-mediated endocytosis (CME) and the macroautophagy/autophagy pathway in yeast and mammals. However, the evidence that connects these two pathways in plants has been limited. Starting from the phenotypic similarities in carbon starvation and immune responses shared between the double mutant of CLC2 (clathrin light chain 2) and CLC3, clc2-1 clc3-1, and the atg2-1 mutant in Arabidopsis, we found that the autophagy pathway is compromised in the clc2-1 clc3-1 mutant. Subsequently, we demonstrated that CLC2 interacts specifically with ATG8h and ATG8i, two clade II ATG8 isoforms. The CLC2-ATG8h/ATG8i interaction depends on an Atg8-family interacting motif (AIM) present in CLC2 and an AIMs docking site (ADS) present in ATG8h, respectively. In addition, CLC2-GFP is subjected to autophagic degradation and the degradation of GFP-ATG8h is significantly reduced in the clc2-1 clc3-1 mutant. Last, simultaneously knocking out ATG8h and ATG8i enhances disease resistance, corroborating the functional relevance of the CLC2-ATG8h/8i interactions. These findings reveal that CME and the autophagy pathway are intersected via CLC2-ATG8h/8i interactions in Arabidopsis.
    Keywords:  Autophagy; Clathrin-mediated endocytosis; Immunity; Senescence; cell death; clathrin light chain
    DOI:  https://doi.org/10.1080/15548627.2024.2414451
  23. Autophagy Rep. 2023 ;pii: 2174337. [Epub ahead of print]2(1):
    Chaperone-Mediated Autophagy Regulates Hypoxic Pathology in Cardiomyocytes.
    Rajeshwary Ghosh, J Scott Pattison.
      Tight regulation of protein degradation pathways is essential for maintaining cardiac homeostasis. The goal of this work was to define the role of chaperone-mediated autophagy (CMA), in cardiomyocytes. CMA acts as a selective degradation pathway of proteins using a cytosolic and lysosomal co-chaperone, HSPA8/HSC70, and the CMA-specific LAMP2A (lysosomal-associated membrane protein 2A) receptor. LAMP2A protein levels are known to be necessary for CMA function. While CMA was shown to exert protection against neurodegenerative disorders and cancer, the role of CMA during cardiac pathology was not known. It was hypothesized that enhancing CMA could mitigate hypoxic pathology in cardiomyocytes. Thus, a genetic gain- and loss-of-CMA-function approach was employed using a Lamp2a-overexpressing adenovirus and a Lamp2a-silencing siRNA, respectively, in primary cardiomyocytes treated with CoCl2 (a hypoxia-mimetic agent) or vehicle control. The experiments performed clearly showed that Lamp2a-overexpression leads to CMA activation that is sufficient to attenuate hypoxia-induced cardiomyocyte death and toxicity.
    Keywords:  Cardiomyocytes; LAMP2A; cell death; chaperone-mediated autophagy; hypoxia; ischemic heart disease; lysosome
    DOI:  https://doi.org/10.1080/27694127.2023.2174337
  24. Front Pharmacol. 2024 ;15 1469830
    The role of SIRT1 in autophagy and drug resistance: unveiling new targets and potential biomarkers in cancer therapy.
    Yujing Tang, Wantao Ju, Yanjun Liu, Qin Deng.
      Cancer, the world's second leading cause of death after cardiovascular diseases, is characterized by hallmarks such as uncontrolled cell growth, metastasis, angiogenesis, hypoxia, and resistance to therapy. Autophagy, a cellular process that can both support and inhibit cancer progression, plays a critical role in cancer development and progression. This process involves the formation of autophagosomes that ultimately fuse with lysosomes to degrade cellular components. A key regulator of this process is Sirtuin 1 (SIRT1), which significantly influences autophagy. This review delves into the role of SIRT1 in modulating autophagy and its broader impacts on carcinogenesis. SIRT1 regulates crucial autophagy mediators, such as AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR), effectively promoting or suppressing autophagy. Beyond its direct effects on autophagy, SIRT1's regulatory actions extend to other cell death processes, including apoptosis and ferroptosis, thereby influencing tumor cell proliferation, metastasis, and chemotherapy responses. These insights underscore the complex interplay between SIRT1 and autophagy, with significant implications for cancer therapy. Targeting SIRT1 and its associated pathways presents a promising strategy to manipulate autophagy in cancer treatment. This review underscores the potential of SIRT1 as a therapeutic target, opening new avenues for enhancing cancer treatment efficacy.
    Keywords:  SIRT1; apoptosis; autophagy; drug resistance; ferroptosis; sirtuin family
    DOI:  https://doi.org/10.3389/fphar.2024.1469830
  25. Int J Mol Med. 2024 Dec;pii: 116. [Epub ahead of print]54(6):
    Autophagy in oral cancer: Promises and challenges (Review).
    Zhou Li, Yao Zhang, Jianhua Lei, Yunxia Wu.
      Autophagy captures damaged or dysfunctional proteins and organelles through the lysosomal pathway to achieve proper cellular homeostasis. Autophagy possesses distinct characteristics and is given recognized functions in numerous physiological and pathological conditions, such as cancer. Early stage cancer development can be stopped by autophagy. After tumor cells have successfully undergone transformation and progressed to a late stage, the autophagy-mediated system of dynamic degradation and recycling will support cancer cell growth and adaptation to various cellular stress responses while preserving energy homeostasis. In the present study, the dual function that autophagy plays in various oral cancer development contexts and stages, the existing arguments for and against autophagy, and the ways in which autophagy contributes to oral cancer modifications, such as carcinogenesis, drug resistance, invasion, metastasis and self-proliferation, are reviewed. Special attention is paid to the mechanisms and functions of autophagy in oral cancer processes, and the most recent findings on the application of certain conventional drugs or natural compounds as novel agents that modulate autophagy in oral cancer are discussed. Overall, further research is needed to determine the validity and reliability of autophagy promotion and inhibition while maximizing the difficult challenge of increasing cancer suppression to improve clinical outcomes.
    Keywords:  autophagy; autophagy mechanism; cancer promotor; cancer suppressor; oral cancer
    DOI:  https://doi.org/10.3892/ijmm.2024.5440
  26. Acta Neuropathol Commun. 2024 Oct 18. 12(1): 164
    Acquisition of neurodegenerative features in isogenic OPTN(E50K) human stem cell-derived retinal ganglion cells associated with autophagy disruption and mTORC1 signaling reduction.
    Kang-Chieh Huang, Cátia Gomes, Yukihiro Shiga, Nicolas Belforte, Kirstin B VanderWall, Sailee S Lavekar, Clarisse M Fligor, Jade Harkin, Shelby M Hetzer, Shruti V Patil, Adriana Di Polo, Jason S Meyer.
      The ability to derive retinal ganglion cells (RGCs) from human pluripotent stem cells (hPSCs) has led to numerous advances in the field of retinal research, with great potential for the use of hPSC-derived RGCs for studies of human retinal development, in vitro disease modeling, drug discovery, as well as their potential use for cell replacement therapeutics. Of all these possibilities, the use of hPSC-derived RGCs as a human-relevant platform for in vitro disease modeling has received the greatest attention, due to the translational relevance as well as the immediacy with which results may be obtained compared to more complex applications like cell replacement. While several studies to date have focused upon the use of hPSC-derived RGCs with genetic variants associated with glaucoma or other optic neuropathies, many of these have largely described cellular phenotypes with only limited advancement into exploring dysfunctional cellular pathways as a consequence of the disease-associated gene variants. Thus, to further advance this field of research, in the current study we leveraged an isogenic hPSC model with a glaucoma-associated mutation in the Optineurin (OPTN) protein, which plays a prominent role in autophagy. We identified an impairment of autophagic-lysosomal degradation and decreased mTORC1 signaling via activation of the stress sensor AMPK, along with subsequent neurodegeneration in OPTN(E50K) RGCs differentiated from hPSCs, and have further validated some of these findings in a mouse model of ocular hypertension. Pharmacological inhibition of mTORC1 in hPSC-derived RGCs recapitulated disease-related neurodegenerative phenotypes in otherwise healthy RGCs, while the mTOR-independent induction of autophagy reduced protein accumulation and restored neurite outgrowth in diseased OPTN(E50K) RGCs. Taken together, these results highlighted that autophagy disruption resulted in increased autophagic demand which was associated with downregulated signaling through mTORC1, contributing to the degeneration of RGCs.
    DOI:  https://doi.org/10.1186/s40478-024-01872-2
  27. J Inherit Metab Dis. 2024 Oct 17.
    An update on autophagy disorders.
    Hormos Salimi Dafsari, Diego Martinelli, Afshin Saffari, Darius Ebrahimi-Fakhari, Manolis Fanto, Carlo Dionisi-Vici, Heinz Jungbluth.
      Macroautophagy is a highly conserved cellular pathway for the degradation and recycling of defective cargo including proteins, organelles, and macromolecular complexes. As autophagy is particularly relevant for cellular homeostasis in post-mitotic tissues, congenital disorders of autophagy, due to monogenic defects in key autophagy genes, share a common "clinical signature" including neurodevelopmental, neurodegenerative, and neuromuscular features, as well as variable abnormalities of the eyes, skin, heart, bones, immune cells, and other organ systems, depending on the expression pattern and the specific function of the defective proteins. Since the clinical and genetic resolution of EPG5-related Vici syndrome, the paradigmatic congenital disorder of autophagy, the widespread use of massively parallel sequencing has resulted in the identification of a growing number of autophagy-associated disease genes, encoding members of the core autophagy machinery as well as related proteins. Recently identified monogenic disorders linking selective autophagy, vesicular trafficking, and other pathways have further expanded the molecular and phenotypical spectrum of congenital disorders of autophagy as a clinical disease spectrum. Moreover, significant advances in basic research have enhanced the understanding of the underlying pathophysiology as a basis for therapy development. Here, we review (i) autophagy in the context of other intracellular trafficking pathways; (ii) the main congenital disorders of autophagy and their typical clinico-pathological signatures; and (iii) the recommended primary health surveillance in monogenic disorders of autophagy based on available evidence. We further discuss recently identified molecular mechanisms that inform the current understanding of autophagy in health and disease, as well as perspectives on future therapeutic approaches.
    Keywords:  autophagy; cellular trafficking; congenital disorders; neurodegeneration; neurodevelopment
    DOI:  https://doi.org/10.1002/jimd.12798
  28. Cells. 2024 Sep 26. pii: 1611. [Epub ahead of print]13(19):
    Natural Autophagy Activators to Fight Age-Related Diseases.
    Vianey M Mundo Rivera, José Roberto Tlacuahuac Juárez, Nadia Mireya Murillo Melo, Norberto Leyva Garcia, Jonathan J Magaña, Joaquín Cordero Martínez, Guadalupe Elizabeth Jiménez Gutierrez.
      The constant increase in the elderly population presents significant challenges in addressing new social, economic, and health problems concerning this population. With respect to health, aging is a primary risk factor for age-related diseases, which are driven by interconnected molecular hallmarks that influence the development of these diseases. One of the main mechanisms that has attracted more attention to aging is autophagy, a catabolic process that removes and recycles damaged or dysfunctional cell components to preserve cell viability. The autophagy process can be induced or deregulated in response to a wide range of internal or external stimuli, such as starvation, oxidative stress, hypoxia, damaged organelles, infectious pathogens, and aging. Natural compounds that promote the stimulation of autophagy regulatory pathways, such as mTOR, FoxO1/3, AMPK, and Sirt1, lead to increased levels of essential proteins such as Beclin-1 and LC3, as well as a decrease in p62. These changes indicate the activation of autophagic flux, which is known to be decreased in cardiovascular diseases, neurodegeneration, and cataracts. The regulated administration of natural compounds offers an adjuvant therapeutic alternative in age-related diseases; however, more experimental evidence is needed to support and confirm these health benefits. Hence, this review aims to highlight the potential benefits of natural compounds in regulating autophagy pathways as an alternative approach to combating age-related diseases.
    Keywords:  age-related diseases; autophagy; cardiopathies; cataract; natural compounds; neurodegeneration
    DOI:  https://doi.org/10.3390/cells13191611
  29. Endocrinol Metab (Seoul). 2024 Oct 14.
    Thyroid Hormone-Mediated Selective Autophagy and Its Implications in Countering Metabolic Dysfunction-Associated Steatotic Liver Disease.
    Rohit A Sinha.
      The influence of thyroid hormone (TH) on liver metabolism has attracted the attention of pharmacologists seeking new treatments for metabolic dysfunction-associated steatotic liver disease (MASLD), an increasingly common metabolic disorder. In this context, the selective induction of autophagy by TH in preclinical models has been identified as a promising mechanism. In this process, TH clears intrahepatic fat through lipophagy while protecting against inflammation and mitochondrial damage in hepatocytes via mitophagy. Furthermore, TH-induced aggrephagy may represent a protective mechanism to mitigate the development of MASLD-associated hepatocellular carcinoma. Considering the defects in autophagy observed during the progression of human MASLD, the induction of autophagy by TH, its metabolites, and its analogs represent a novel strategy to combat hepatic damage across the MASLD spectrum.
    Keywords:  3,5-Diiodothyronine; Autophagy; Metabolic dysfunction-associated steatohepatitis; Metabolic dysfunction-associated steatotic liver disease; Mitophagy; Resmetirom; Thyroid hormones
    DOI:  https://doi.org/10.3803/EnM.2024.2068
  30. Autophagy. 2024 Oct 12.
    Reticulophagy and viral infection.
    Alexa Wilson, Craig McCormick.
      All viruses are obligate intracellular parasites that use host machinery to synthesize viral proteins. In infected eukaryotes, viral secreted and transmembrane proteins are synthesized at the endoplasmic reticulum (ER). Many viruses refashion ER membranes into bespoke factories where viral products accumulate while evading host pattern recognition receptors. ER processes are tightly regulated to maintain cellular homeostasis, so viruses must either conform to ER regulatory mechanisms or subvert them to ensure efficient viral replication. Reticulophagy is a catabolic process that directs lysosomal degradation of ER components. There is accumulating evidence that reticulophagy serves as a form of antiviral defense; we call this defense "xERophagy" to acknowledge its relationship to xenophagy, the catabolic degradation of microorganisms by macroautophagy/autophagy. In turn, viruses can subvert reticulophagy to suppress host antiviral responses and support efficient viral replication. Here, we review the evidence for functional interplay between viruses and the host reticulophagy machinery.
    Keywords:  Autophagy; endoplasmic reticulum; reticulophagy; unfolded protein response; virus
    DOI:  https://doi.org/10.1080/15548627.2024.2414424
  31. Autophagy. 2024 Oct 16. 1-17
    Copper aggravated synaptic damage after traumatic brain injury by downregulating BNIP3-mediated mitophagy.
    Hanxiao Chang, Weiwei Zhang, Lei Xu, Zheng Li, Chao Lin, Yuqi Shen, Guangjian Zhang, Lei Mao, Chencheng Ma, Ning Liu, Hua Lu.
      Synaptic damage is a crucial pathological process in traumatic brain injury. However, the mechanisms driving this process remain poorly understood. In this report, we demonstrate that the accumulation of damaged mitochondria, resulting from impaired mitphagy, plays a significant role in causing synaptic damage. Moreover, copper induced downregulation of BNIP3 is a key player in regulating mitophagy. DMSA alleviates synaptic damage and mitochondrial dysfunction by promoting urinary excretion of copper. Mechanistically, we find that copper downregulate BNIP3 by increasing the nuclear translocation of NFKB, which is triggered by TRIM25-mediated ubiquitination-dependent degradation of NFKBIA. Our study underscores the importance of copper accumulation in the regulation of BNIP3-mediated mitophagy and suggests that therapeutic targeting of the copper-TRIM25-NFKB-BNIP3 axis holds promise to attenuate synaptic damage after traumatic brain injury.
    Keywords:  BNIP3; TRIM25; copper; mitophagy; traumatic brain injury
    DOI:  https://doi.org/10.1080/15548627.2024.2409613
  32. bioRxiv. 2024 Oct 13. pii: 2024.10.12.618047. [Epub ahead of print]
    Synergistic Role of Amino Acids in Enhancing mTOR Activation Through Lysosome Positioning.
    Oralia M Kolaczkowski, Baley A Goodson, Valeria Montenegro Vazquez, Jingyue Jia, Aadil Qadir Bhat, Tae-Hyung Kim, Jing Pu.
      Lysosome positioning, or lysosome cellular distribution, is critical for lysosomal functions in response to both extracellular and intracellular cues. Amino acids, as essential nutrients, have been shown to promote lysosome movement toward the cell periphery. Peripheral lysosomes are involved in processes such as lysosomal exocytosis, cell migration, and metabolic signaling-functions that are particularly important for cancer cell motility and growth. However, the specific types of amino acids that regulate lysosome positioning, their underlying mechanisms, and their connection to amino acid-regulated metabolic signaling remain poorly understood. In this study, we developed a high-content imaging system for unbiased, quantitative analysis of lysosome positioning. We examined the 15 amino acids present in cell culture media and found that 10 promoted lysosome redistribution toward the cell periphery to varying extents, with aromatic amino acids showing the strongest effect. This redistribution was mediated by promoting outward transport through SLC38A9-BORC-kinesin 1/3 axis and simultaneously reducing inward transport via inhibiting the recruitment of Rab7 and JIP4 onto lysosomes. When examining the effects of amino acids on mTOR activation-a central regulator of cell metabolism-we found that the amino acids most strongly promoting lysosome dispersal, such as phenylalanine, did not activate mTOR on their own. However, combining phenylalanine with arginine, which activates mTOR without affecting lysosome positioning, synergistically enhanced mTOR activity. This synergy was lost when lysosomes failed to localize to the cell periphery, as observed in kinesin 1/3 knockout (KO) cells. Furthermore, breast cancer cells exhibited heightened sensitivity to phenylalanine-induced lysosome dispersal compared to noncancerous breast cells. Inhibition of LAT1, the amino acid transporter responsible for phenylalanine uptake, reduced peripheral lysosomes and impaired cancer cell migration and proliferation, highlighting the importance of lysosome positioning in these coordinated cellular activities. In summary, amino acid-regulated lysosome positioning and mTOR signaling depend on distinct sets of amino acids. Combining lysosome-dispersing amino acids with mTOR-activating amino acids synergistically enhances mTOR activation, which may be particularly relevant in cancer cells.
    DOI:  https://doi.org/10.1101/2024.10.12.618047
  33. Chem Soc Rev. 2024 Oct 17.
    Harnessing luciferase chemistry in regulated cell death modalities and autophagy: overview and perspectives.
    Saman Hosseinkhani, Mojdeh Amandadi, Parisa Ghanavatian, Fateme Zarein, Farangis Ataei, Maryam Nikkhah, Peter Vandenabeele.
      Regulated cell death is a fate of cells in (patho)physiological conditions during which extrinsic or intrinsic signals or redox equilibrium pathways following infection, cellular stress or injury are coupled to cell death modalities like apoptosis, necroptosis, pyroptosis or ferroptosis. An immediate survival response to cellular stress is often induction of autophagy, a process that deals with removal of aggregated proteins and damaged organelles by a lysosomal recycling process. These cellular processes and their regulation are crucial in several human diseases. Exploiting high-throughput assays which discriminate distinct cell death modalities and autophagy are critical to identify potential therapeutic agents that modulate these cellular responses. In the past few years, luciferase-based assays have been widely developed for assessing regulated cell death and autophagy pathways due to their simplicity, sensitivity, known chemistry, different spectral properties and high-throughput potential. Here, we review basic principles of bioluminescent reactions from a mechanistic perspective, along with their implication in vitro and in vivo for probing cell death and autophagy pathways. These include applying luciferase-, luciferin-, and ATP-based biosensors for investigating regulated cell death modalities. We discuss multiplex bioluminescence platforms which simultaneously distinguish between the various cell death phenomena and cellular stress recovery processes such as autophagy. We also highlight the recent technological achievements of bioluminescent tools for the prediction of drug effectiveness in pathways associated with regulated cell death.
    DOI:  https://doi.org/10.1039/d3cs00743j
  34. Biomed Environ Sci. 2024 Sep 20. 37(9): 1030-1043
    MicroRNA-451 from Human Umbilical Cord-Derived Mesenchymal Stem Cell Exosomes Inhibits Alveolar Macrophage Autophagy via Tuberous Sclerosis Complex 1/Mammalian Target of Rapamycin Pathway to Attenuate Burn-Induced Acute Lung Injury in Rats.
    Zhi Gang Jia, Lin Li, Peng Zhao, Guo Fei, Shuang Ru Li, Qin Qin Song, Guang Peng Liu, Ji Song Liu.
       Objective: Our previous studies established that microRNA (miR)-451 from human umbilical cord mesenchymal stem cell-derived exosomes (hUC-MSC-Exos) alleviates acute lung injury (ALI). This study aims to elucidate the mechanisms by which miR-451 in hUC-MSC-Exos reduces ALI by modulating macrophage autophagy.
    Methods: Exosomes were isolated from hUC-MSCs. Severe burn-induced ALI rat models were treated with hUC-MSC-Exos carrying the miR-451 inhibitor. Hematoxylin-eosin staining evaluated inflammatory injury. Enzyme-linked immunosorbnent assay measured lipopolysaccharide (LPS), tumor necrosis factor-α, and interleukin-1β levels. qRT-PCR detected miR-451 and tuberous sclerosis complex 1 (TSC1) expressions. The regulatory role of miR-451 on TSC1 was determined using a dual-luciferase reporter system. Western blotting determined TSC1 and proteins related to the mammalian target of rapamycin (mTOR) pathway and autophagy. Immunofluorescence analysis was conducted to examine exosomes phagocytosis in alveolar macrophages and autophagy level.
    Results: hUC-MSC-Exos with miR-451 inhibitor reduced burn-induced ALI and promoted macrophage autophagy. MiR-451 could be transferred from hUC-MSCs to alveolar macrophages via exosomes and directly targeted TSC1. Inhibiting miR-451 in hUC-MSC-Exos elevated TSC1 expression and inactivated the mTOR pathway in alveolar macrophages. Silencing TSC1 activated mTOR signaling and inhibited autophagy, while TSC1 knockdown reversed the autophagy from the miR-451 inhibitor-induced.
    Conclusion: miR-451 from hUC-MSC exosomes improves ALI by suppressing alveolar macrophage autophagy through modulation of the TSC1/mTOR pathway, providing a potential therapeutic strategy for ALI.
    Keywords:  Acute lung injury; Autophagy; Human umbilical cord mesenchymal stem cell-derived exosomes; Mammalian target of rapamycin pathway; MicroRNA-451; Tuberous sclerosis complex 1
    DOI:  https://doi.org/10.3967/bes2024.128
  35. Nat Commun. 2024 Oct 16. 15(1): 8927
    Coronavirus M protein promotes mitophagy over virophagy by recruiting PDPK1 to phosphorylate SQSTM1 at T138.
    Yahui Li, Chunyan Li, Chenchen Zhao, Jiayu Wu, Ya Zhu, Fei Wang, Jiepeng Zhong, Yan Yan, Yulan Jin, Weiren Dong, Jinyang Chen, Xianghong Yang, Jiyong Zhou, Boli Hu.
      Autophagy plays a dual role in coronavirus infection, facilitating the elimination of either proviral components (virophagy) or antiviral factors such as mitochondria (mitophagy), leading to complex mechanisms of immune evasion. Understanding the mechanisms that govern the switch between the autophagic degradation of deleterious or beneficial substrates in coronavirus infection is crucial for developing precise drug targets to treat virus-induced diseases. However, this switch remains largely unknown. Using a dual split-fluorescence assay, we identify PDPK1 as a negative regulator of innate immunity, directing the transition from virophagy to mitophagy through the phosphorylation of SQSTM1 at T138. Remarkably, a PDPK1-targeting peptide inhibits the replication of various RNA viruses by restoring innate immunity through enhanced virophagy and suppressed mitophagy, thereby protecting female mice from lethal infections. These findings underscore the detrimental role of PDPK1 in innate immunity by orchestrating the shift from virophagy to mitophagy, positioning PDPK1 as a promising pharmacological target for effectively combating a broad spectrum of virus infections.
    DOI:  https://doi.org/10.1038/s41467-024-53100-z
  36. Trends Pharmacol Sci. 2024 Oct 16. pii: S0165-6147(24)00187-1. [Epub ahead of print]
    Enhancing CNS mitophagy: drug development and disease-relevant models.
    Krishayant S Dhar, Brendan Townsend, Andrew P Montgomery, Jonathan J Danon, Julia K Pagan, Michael Kassiou.
      Mitophagy, the selective degradation of mitochondria, is impaired in many neurodegenerative diseases (NDs), resulting in an accumulation of dysfunctional mitochondria and neuronal damage. Although enhancing mitophagy shows promise as a therapeutic strategy, the clinical significance of mitophagy activators remains uncertain due to limited understanding and poor representation of mitophagy in the central nervous system (CNS). This review explores recent insights into which mitophagy pathways to target and the extent of modulation necessary to be therapeutic towards NDs. We also highlight the complexities of mitophagy in the CNS, highlighting the need for disease-relevant models. Last, we outline crucial aspects of in vitro models to consider during drug discovery, aiming to bridge the gap between preclinical research and clinical applications in treating NDs through mitophagy modulation.
    Keywords:  central nervous system; clinical relevance; disease models; drug development; mitochondrial dysfunction; mitophagy; neurodegenerative diseases
    DOI:  https://doi.org/10.1016/j.tips.2024.09.002
  37. EMBO Mol Med. 2024 Oct 14.
    Unraveling autophagic imbalances and therapeutic insights in Mecp2-deficient models.
    Alessandro Esposito, Tommaso Seri, Martina Breccia, Marzia Indrigo, Giuseppina De Rocco, Francesca Nuzzolillo, Vanna Denti, Francesca Pappacena, Gaia Tartaglione, Simone Serrao, Giuseppe Paglia, Luca Murru, Stefano de Pretis, Jean-Michel Cioni, Nicoletta Landsberger, Fabrizia Claudia Guarnieri, Michela Palmieri.
      Loss-of-function mutations in MECP2 are associated to Rett syndrome (RTT), a severe neurodevelopmental disease. Mainly working as a transcriptional regulator, MeCP2 absence leads to gene expression perturbations resulting in deficits of synaptic function and neuronal activity. In addition, RTT patients and mouse models suffer from a complex metabolic syndrome, suggesting that related cellular pathways might contribute to neuropathogenesis. Along this line, autophagy is critical in sustaining developing neuron homeostasis by breaking down dysfunctional proteins, lipids, and organelles.Here, we investigated the autophagic pathway in RTT and found reduced content of autophagic vacuoles in Mecp2 knock-out neurons. This correlates with defective lipidation of LC3B, probably caused by a deficiency of the autophagic membrane lipid phosphatidylethanolamine. The administration of the autophagy inducer trehalose recovers LC3B lipidation, autophagosomes content in knock-out neurons, and ameliorates their morphology, neuronal activity and synaptic ultrastructure. Moreover, we provide evidence for attenuation of motor and exploratory impairment in Mecp2 knock-out mice upon trehalose administration. Overall, our findings open new perspectives for neurodevelopmental disorders therapies based on the concept of autophagy modulation.
    Keywords:  Autophagy; MeCP2; Metabolism; Neurons; Rett Syndrome
    DOI:  https://doi.org/10.1038/s44321-024-00151-w
  38. Cell. 2024 Oct 15. pii: S0092-8674(24)01094-8. [Epub ahead of print]
    PLD3 and PLD4 synthesize S,S-BMP, a key phospholipid enabling lipid degradation in lysosomes.
    Shubham Singh, Ulrich E Dransfeld, Yohannes A Ambaw, Joshua Lopez-Scarim, Robert V Farese, Tobias C Walther.
      Bis(monoacylglycero)phosphate (BMP) is an abundant lysosomal phospholipid required for degradation of lipids, particularly gangliosides. Alterations in BMP levels are associated with neurodegenerative diseases. Unlike typical glycerophospholipids, lysosomal BMP has two chiral glycerol carbons in the S (rather than the R) stereo-conformation, protecting it from lysosomal degradation. How this unusual and yet crucial S,S-stereochemistry is achieved is unknown. Here, we report that phospholipases D3 and D4 (PLD3 and PLD4) synthesize lysosomal S,S-BMP, with either enzyme catalyzing the critical glycerol stereo-inversion reaction in vitro. Deletion of PLD3 or PLD4 markedly reduced BMP levels in cells or in murine tissues where either enzyme is highly expressed (brain for PLD3; spleen for PLD4), leading to gangliosidosis and lysosomal abnormalities. PLD3 mutants associated with neurodegenerative diseases, including risk of Alzheimer's disease, diminished PLD3 catalytic activity. We conclude that PLD3/4 enzymes synthesize lysosomal S,S-BMP, a crucial lipid for maintaining brain health.
    Keywords:  Alzheimer’s disease; dementia; gangliosides; lipid metabolism; lysosome; neurodegeneration; phospholipid
    DOI:  https://doi.org/10.1016/j.cell.2024.09.036
  39. J Mater Chem B. 2024 Oct 17.
    Water-dispersible fluorescent COFs disturb lysosomal autophagy to boost cascading enzymatic chemodynamic-starvation therapy.
    Hui Liu, Wenxin Lv, Darambazar Gantulga, Yi Wang.
      Cascading enzymatic therapy is a promising approach in cancer treatment. However, its effectiveness is often hindered by enzyme inactivation, limited exposure of active sites, cancer cell self-protection mechanisms such as autophagy, and non-specific toxicity, which can lead to treatment failure. To address these challenges, we used a low-temperature aqueous-phase synthesis method to create semi-crystalline, water-dispersible fluorescent COF nanospheres. These nanospheres can stably load glucose oxidase (GOx) and ultrafine Fe2O3 nanozymes, allowing for convenient coating with tumor cell membranes to form a uniform tumor-targeted cascading enzymatic nanosystem (CFGM). This system promotes a cycle of tumor glucose depletion, reactive oxygen species (ROS) generation, and oxygen production, facilitating tumor-targeted starvation therapy (ST) and chemodynamic therapy (CDT). Notably, the semi-crystalline COF carrier within this system can degrade slowly under mildly acidic conditions, forming large aggregates that damage lysosomes and disrupt lysosomal autophagy, thereby eliminating the autophagy protection of cancer cells activated by the combined ST. This synergistic approach enhances the catalytic inhibition of tumors. Our research thus provides an alternative COF-based platform and strategy for effective cancer treatment.
    DOI:  https://doi.org/10.1039/d4tb01534g
  40. Exp Eye Res. 2024 Oct 16. pii: S0014-4835(24)00351-8. [Epub ahead of print] 110129
    Regualtion of LAMTOR1 by Oxidative Stress in Retinal Pigment Epithelium: Implications for Age-Related Macular Degeneration Pathogenesis.
    Jingjing Cai, Fei Liao, Yandie Mao, Shuyi Liu, Xiong Wu, Shiqi Tang, Simin Wang, Ge Shan, Shengzhou Wu.
      Oxidative stress is a critical pathogenic factor for age-related macular degeneration (AMD). Autophagy serves as a mechanism to counteract oxidative stress. LAMTOR1 regulates mTORC1 activity by recruiting or disassembling it on the lysosome under the addition or deprivation of amino acids. This regulation inhibits or enhances autophagy. Our study investigates whether oxidative stress impacts LAMTOR1, thereby adapting to oxidative conditions. We employed oxidative stressors, menadione (VK3) and 4-hydroxynonenal (4-HNE), and observed a reduction of LAMTOR1 in both human and mouse retinal pigment epithelium (RPE) following short-term (1h) and prolonged exposures (24h). Nrf2 overexpression increased both lamtor1 mRNA and LAMTOR1 protein in the RPE. To determine if Nrf2 regulates lamtor1 transcription, we cloned the deletion mutants of the lamtor1 promoter into a luciferase reporter. Although the promoter contained antioxidant response elements, transcriptional activity depended on the interaction between Nrf2 and the constructs containing the transcriptional start site. Moreover, Nrf2-driven transcription was significantly reduced by an inhibitor of histone acetyltransferase, p300. Correspondingly, Nrf2 overexpression increased levels of acetylated histone3 and p300. The reduction in LAMTOR1 by 4-HNE was reversed by pepstatin A and NH4Cl which block lysosomal degradation. 4-HNE increased TFEB nuclear translocation which was reversed by LAMTOR1 overexpression. In vivo, LAMTOR1 levels decreased in the photoreceptor and RPE layers of NaIO3-injected mice, compared to PBS-injected controls. In conclusion, oxidative injury reduces LAMTOR1, predominantly through lysosomal degradation although Nrf2-mediated histone acetylation enhances lamtor1 transcription. This study reveals a previously unrecognized regulatory mechanism of lamtor1 by oxidative stress, suggesting a novel role for LAMTOR1 in the pathogenesis of AMD.
    Keywords:  Age-related macular degeneration; Autophagy; Histone acetyltransferase; Histone deacetylase; Lysosome; mTORC1
    DOI:  https://doi.org/10.1016/j.exer.2024.110129
  41. J Cell Biol. 2025 Jan 06. pii: e202312141. [Epub ahead of print]224(1):
    Rapid turnover of CTLA4 is associated with a complex architecture of reversible ubiquitylation.
    Pei Yee Tey, Almut Dufner, Klaus-Peter Knobeloch, Jonathan N Pruneda, Michael J Clague, Sylvie Urbé.
      The immune checkpoint regulator CTLA4 is an unusually short-lived membrane protein. Here, we show that its lysosomal degradation is dependent on ubiquitylation at lysine residues 203 and 213. Inhibition of the v-ATPase partially restores CTLA4 levels following cycloheximide treatment, but also reveals a fraction that is secreted in exosomes. The endosomal deubiquitylase, USP8, interacts with CTLA4, and its loss enhances CTLA4 ubiquitylation in cancer cells, mouse CD4+ T cells, and cancer cell-derived exosomes. Depletion of the USP8 adapter protein, HD-PTP, but not ESCRT-0 recapitulates this cellular phenotype but shows distinct properties vis-à-vis exosome incorporation. Re-expression of wild-type USP8, but neither a catalytically inactive nor a localization-compromised ΔMIT domain mutant can rescue delayed degradation of CTLA4 or counteract its accumulation in clustered endosomes. UbiCRest analysis of CTLA4-associated ubiquitin chain linkages identifies a complex mixture of conventional Lys63- and more unusual Lys27- and Lys29-linked polyubiquitin chains that may underly the rapidity of protein turnover.
    DOI:  https://doi.org/10.1083/jcb.202312141
  42. Front Pharmacol. 2024 ;15 1444657
    The role of autophagy in pancreatic diseases.
    Wen-Gang Zhang, Qing-Zhen Wu, Bo-Zong Shao.
      Pancreatic diseases such as pancreatitis and pancreatic cancer represent significant health challenges characterized by high mortality rates and limited survival durations. Autophagy, a crucial cellular catabolic process, has emerged as a focal point in understanding various pathological conditions, spanning inflammation-related disorders to malignant neoplasms. This comprehensive review aims to elucidate the biological intricacies of autophagy and its pivotal roles within two extensively researched pancreatic diseases, namely pancreatitis and pancreatic cancer, drawing upon recent scholarly contributions. The discussion will delve into the nuanced mechanisms underlying autophagy's involvement in these diseases, shedding light on its potential as a therapeutic target. Furthermore, the review will explore cutting-edge therapeutic interventions leveraging autophagy regulation for managing pancreatitis and pancreatic cancer. Through this analysis, we endeavor to offer novel insights into the pathophysiology of pancreatic disorders and contribute to the development of innovative therapeutic modalities in this challenging clinical domain.
    Keywords:  autophagy; inflammation; pancreatic cancer; pancreatic disease; pancreatitis
    DOI:  https://doi.org/10.3389/fphar.2024.1444657
  43. Breast Cancer Res. 2024 Oct 18. 26(1): 143
    Autophagy is required for mammary tumor recurrence by promoting dormant tumor cell survival following therapy.
    Samantha Dwyer, Jason Ruth, Hans E Seidel, Amelie A Raz, Lewis A Chodosh.
       BACKGROUND: Mortality from breast cancer is principally due to tumor recurrence. Recurrent breast cancers arise from the pool of residual tumor cells, termed minimal residual disease, that survive treatment and may exist in a dormant state for 20 years or more following treatment of the primary tumor. As recurrent breast cancer is typically incurable, understanding the mechanisms underlying dormant tumor cell survival is a critical priority in breast cancer research. The importance of this goal is further underscored by emerging evidence suggesting that targeting dormant residual tumor cells in early-stage breast cancer patients may be a means to prevent tumor recurrence and its associated mortality. In this regard, the role of autophagy in dormant tumor cell survival and recurrence remains unresolved, with conflicting reports of both pro-survival/recurrence-promoting and pro-death/recurrence-suppressing effects of autophagy inhibition in dormant tumor cells. Resolving this question has important clinical implications.
    METHODS: We used genetically engineered mouse models that faithfully recapitulate key features of human breast cancer progression, including minimal residual disease, tumor dormancy, and recurrence. We used genetic and pharmacological approaches to inhibit autophagy, including treatment with chloroquine, genetic knockdown of ATG5 or ATG7, or deletion of BECN and determined their effects on dormant tumor cell survival and recurrence.
    RESULTS: We demonstrate that the survival and recurrence of dormant mammary tumor cells following therapy is dependent upon autophagy. We find that autophagy is induced in vivo following HER2 downregulation and remains activated in dormant residual tumor cells. Using genetic and pharmacological approaches we show that inhibiting autophagy by chloroquine administration, ATG5 or ATG7 knockdown, or deletion of a single allele of the tumor suppressor Beclin 1 is sufficient to inhibit mammary tumor recurrence, and that autophagy inhibition results in the death of dormant mammary tumor cells in vivo.
    CONCLUSIONS: Our findings demonstrate a pro-tumorigenic role for autophagy in tumor dormancy and recurrence following therapy, reveal that dormant tumor cells are uniquely reliant upon autophagy for their survival, and indicate that targeting dormant residual tumor cells by inhibiting autophagy impairs tumor recurrence. These studies identify a pharmacological target for a cellular state that is resistant to commonly used anti-neoplastic agents and suggest autophagy inhibition as an approach to reduce dormant minimal residual disease in order to prevent lethal tumor recurrence.
    Keywords:  Autophagy; Breast cancer; Dormancy; HER2/neu; Mouse model; Recurrence
    DOI:  https://doi.org/10.1186/s13058-024-01878-7
  44. Autophagy. 2024 Oct 12.
    Should it stay or should it go: gap junction protein GJA1/Cx43 conveys damaged lysosomes to the cell periphery to potentiate exocytosis.
    Neuza Domingues, Teresa Ribeiro-Rodrigues, Henrique Girão.
      GJA1/Cx43 (gap junction protein alpha 1) has long been associated with gap junctions-mediated communication between adjacent cells. However, recent data have defied this concept, with studies implicating GJA1 in other biological processes, such as macroautophagy/autophagy regulation, mitochondrial activity and extracellular vesicles biology. In our recent study we unveiled an additional role played by GJA1 in lysosomal trafficking. We demonstrate that GJA1 promotes the exocytosis of damaged lysosomes, through a mechanism that relies on ACTR2/ARP2-ACTR3/ARP3-dependent actin remodeling. Our findings ascribe to GJA1 an important role during pathogen infection and lysosomal storage disorders, favoring the release of dysfunctional lysosomes.
    Keywords:  Actin; Arp2; gap junction protein alpha 1/Connexin43; lysophagy; lysosomal damage; lysosomal exocytosis
    DOI:  https://doi.org/10.1080/15548627.2024.2408711
  45. Immunol Rev. 2024 Oct 17.
    Regulation of the NLRP3 inflammasome by autophagy and mitophagy.
    Suman Gupta, Suzanne L Cassel, Fayyaz S Sutterwala, Jargalsaikhan Dagvadorj.
      The NLRP3 inflammasome is a multiprotein complex that upon activation by the innate immune system drives a broad inflammatory response. The primary initial mediators of this response are pro-IL-1β and pro-IL-18, both of which are in an inactive form. Formation and activation of the NLRP3 inflammasome activates caspase-1, which cleaves pro-IL-1β and pro-IL-18 and triggers the formation of gasdermin D pores. Gasdermin D pores allow for the secretion of active IL-1β and IL-18 initiating the organism-wide inflammatory response. The NLRP3 inflammasome response can be beneficial to the host; however, if the NLRP3 inflammasome is inappropriately activated it can lead to significant pathology. While the primary components of the NLRP3 inflammasome are known, the precise details of assembly and activation are less well defined and conflicting. Here, we discuss several of the proposed pathways of activation of the NLRP3 inflammasome. We examine the role of subcellular localization and the reciprocal regulation of the NLRP3 inflammasome by autophagy. We focus on the roles of mitochondria and mitophagy in activating and regulating the NLRP3 inflammasome. Finally, we detail the impact of pathologic NLRP3 responses in the development and manifestations of pulmonary disease.
    Keywords:  NLRP3; caspase‐1; inflammasome; lung injury; mitochondria
    DOI:  https://doi.org/10.1111/imr.13410
  46. Anal Cell Pathol (Amst). 2024 ;2024 2639464
    AZD8055 Is More Effective Than Rapamycin in Inhibiting Proliferation and Promoting Mitochondrial Clearance in Erythroid Differentiation.
    Qian Liu, Tao Hao, Ze Lin, Yipeng Fang, Lei Li, Daqi Huang, Jianbo Wu, Yanchao Zhao, Xin Zhang.
      Background: As an important downstream effector of various signaling pathways, mTOR plays critical roles in regulating many physiological processes including erythropoiesis. It is composed of two distinct complexes, mTORC1 and mTORC2, which differ in their components and downstream signaling effects. Our previous study revealed that the inhibition of mTORC1 by rapamycin significantly repressed the erythroid progenitor expansion in the early stage but promoted enucleation and mitochondria clearance in the late stage of erythroid differentiation. However, the particular roles and differences of mTORC1 and mTORC2 in the regulation of erythropoiesis still remain largely unknown. In the present study, we investigated the comparative effects of dual mTORC1/mTORC2 mTOR kinase inhibitor AZD8055 and mTORC1 inhibitor rapamycin on erythroid differentiation in K562 cells induced by hemin and erythropoiesis in β-thalassemia mouse model. Materials and Methods: In vitro erythroid differentiation model of hemin-induced K562 cells and β-thalassemia mouse model were treated with AZD8055 and rapamycin. Cell Counting Kit-8 was used to detect cell viability. The cell proliferation, cell cycle, erythroid surface marker expression, mitochondrial content, and membrane potential were determined and analyzed by flow cytometry and laser scanning confocal microscopy. Globin gene expression during erythroid differentiation was measured by RT-qPCR. The mTORC2/mTORC1 and autophagy pathway was evaluated using western blotting. Results: Both AZD8055 and rapamycin treatments increased the expression levels of the erythroid differentiation-specific markers, CD235a, α-globin, γ-globin, and ε-globin. Notably, AZD8055 suppressed the cell proliferation and promoted the mitochondrial clearance of hemin-induced K562 cells more effectively than rapamycin. In a mouse model of β-thalassemia, both rapamycin and AZD8055 remarkably improve erythroid cell maturation and anemia. Moreover, AZD8055 and rapamycin treatment inhibited the mTORC1 pathway and enhanced autophagy, whereas AZD8055 enhanced autophagy more effectively than rapamycin. Indeed, AZD8055 treatment inhibited both mTORC2 and mTORC1 pathway in hemin-induced K562 cells. Conclusion: AZD8055 is more effective than rapamycin in inhibiting proliferation and promoting mitochondrial clearance in erythroid differentiation, which might provide us one more therapeutic option other than rapamycin for ineffective erythropoiesis treatment in the future. These findings also provide some preliminary information indicating the roles of mTORC1 and mTORC2 in erythropoiesis, and further studies are necessary to dissect the underlying mechanisms.
    DOI:  https://doi.org/10.1155/2024/2639464
  47. Sci Rep. 2024 10 12. 14(1): 23882
    Autophagy and inflammasome activation are associated with poor response to FLT3 inhibitors in patients with FLT3-ITD acute myeloid leukemia.
    Brunno Gilberto Santos de Macedo, Manuela Albuquerque de Melo, Diego Antonio Pereira-Martins, João Agostinho Machado-Neto, Fabíola Traina.
      Beyond its clinical diversity and severity, acute myeloid leukemia (AML) is known for its complex molecular background and for rewiring biological processes to aid disease onset and maintenance. FLT3 mutations are among the most recurring molecular entities that cooperatively drive AML, and their inhibition is a critical molecularly oriented therapeutic strategy. Despite being a promising avenue, it still faces challenges such as intrinsic and acquired drug resistance, which led us to investigate whether and how autophagy and inflammasome interact and whether this interaction could be leveraged to enhance FLT3 inhibition as a therapeutic strategy. We observed a strong and positive correlation between the expression of key genes associated with autophagy and the inflammasome. Gene set enrichment analysis of the FLT3-ITD samples and their ex vivo response to five different FLT3 inhibitors revealed a common molecular signature compatible with autophagy and inflammasome activation across all poor responders. Inflammasome activation was also shown to strongly increase the likelihood of a poor ex vivo response to the FLT3 inhibitors quizartinib and sorafenib. These findings reveal a distinct molecular pattern within FLT3-ITD AML samples that underscores the necessity for further exploration into how approaching these supportive parallel yet altered pathways could improve therapeutic strategies.
    Keywords:   Drug resistance; Acute myeloid leukemia; Autophagy; FLT3-ITD inhibitors; Inflammasome
    DOI:  https://doi.org/10.1038/s41598-024-74168-z
  48. J Neuroinflammation. 2024 Oct 15. 21(1): 261
    Glutamine metabolism modulates microglial NLRP3 inflammasome activity through mitophagy in Alzheimer's disease.
    Zhixin Zhang, Miao Li, Xiang Li, Zhiyang Feng, Gan Luo, Ying Wang, Xiaoyan Gao.
      The NLR family pyrin domain containing 3 (NLRP3) inflammasome in microglia is intimately linked to the pathogenesis of Alzheimer's disease (AD). Although NLRP3 inflammasome activity is regulated by cellular metabolism, the underlying mechanism remains elusive. Here, we found that under the pathological conditions of AD, the activation of NLRP3 inflammasome in microglia is accompanied by increased glutamine metabolism. Suppression of glutaminase, the rate limiting enzyme in glutamine metabolism, attenuated the NLRP3 inflammasome activation both in the microglia of AD mice and cultured inflammatory microglia. Mechanistically, inhibiting glutaminase blocked the anaplerotic flux of glutamine to the tricarboxylic acid cycle and amino acid synthesis, down-regulated mTORC1 signaling by phosphorylating AMPK, which stimulated mitophagy and limited the accumulation of intracellular reactive oxygen species, ultimately prevented the activation of NLRP3 inflammasomes in activated microglia during AD. Taken together, our findings suggest that glutamine metabolism regulates the activation of NLRP3 inflammasome through mitophagy in microglia, thus providing a potential therapeutic target for AD treatment.
    Keywords:  Alzheimer’s disease; Glutamine metabolism; Microglia; Mitophagy; NLRP3 inflammasome
    DOI:  https://doi.org/10.1186/s12974-024-03254-w
  49. Cytojournal. 2024 ;21 33
    Evidence for the potential role of m6A modification in regulating autophagy in models of amyotrophic lateral sclerosis.
    Di An, Jingzhe Han, Pingping Fang, Yi Bu, Guang Ji, Mingjuan Liu, Jinliang Deng, Xueqin Song.
       Objective: Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disease. Research indicates that N6-methyladenosine (m6A) modification plays a crucial role in cellular autophagy during ALS development. This study investigates the role of autophagy in ALS, with a focus on the effect of messenger ribonucleic acid m6A methylation modification on disease progression.
    Material and Methods: We compared m6A levels and regulatory molecule expressions in transgenic superoxide dismutase (SOD1)-G93A and non-transgenic mice, categorized into end-stage and control groups, using quantitative polymerase chain reaction and Western blotting. The NSC-34 cell line, which was modified to model ALS, enabled the investigation of apoptosis, autophagy, and autophagy disruption through terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick-end labeling assays, Western blotting, and fluorescent staining.
    Results: Our findings indicate significantly elevated m6A methylation levels in ALS mice (0.262 ± 0.005) compared with the controls (0.231 ± 0.003) and in the ALS model cells (0.242±0.005) relative to those belonging to the wild-type control group (0.183 ± 0.007). Furthermore, the proteins involved in m6A RNA modification differed between groups, which suggest impaired autophagy flux in the ALS models.
    Conclusion: These results suggest that m6A methylation may accelerate ALS progression through the disruption of autophagic processes. Our study underscores the role of m6A methylation in the pathology of ALS and proposes the targeting of m6A methylation as a potential therapeutic strategy for disease treatment. Although this study primarily used transgenic SOD1-G93A mice and NSC-34 cell models to investigate ALS pathology, potential differences in disease mechanisms between animal models and humans must be considered. Although a correlation was detected between m6A methylation levels and autophagy disruption in ALS, the study primarily established an association rather than provided detailed mechanistic insights.
    Keywords:  Amyotrophic lateral sclerosis; Autophagy; Methylation; Modification; N6-methyladenosine
    DOI:  https://doi.org/10.25259/Cytojournal_101_2024
  50. Front Pharmacol. 2024 ;15 1491563
    Autophagy is a promising process for linking inflammation and redox homeostasis in Down syndrome.
    Xuehai Ma, Weimin Li, Jun Ma, Zhongcheng Han, Shoulong Deng, Sutian Wang.
      Trisomy 21, characterized by the presence of an additional chromosome 21, leads to a set of clinical features commonly referred to as Down syndrome (DS). The pathological phenotypes observed in DS are caused by a combination of factors, such as mitochondrial dysfunction, neuroinflammation, oxidative stress, disrupted metabolic patterns, and changes in protein homeostasis and signal transduction, and these factors collectively induce neurological alterations. In DS, the triplication of chromosome 21 and the micronuclei arising from the missegregation of chromosomes are closely associated with inflammation and the development of redox imbalance. Autophagy, an essential biological process that affects cellular homeostasis, is a powerful tool to facilitate the degradation of redundant or dysfunctional cytoplasmic components, thereby enabling the recycling of their constituents. Targeting the autophagy process has been suggested as a promising method to balance intracellular inflammation and oxidative stress and improve mitochondrial dysfunction. In this review, we summarize the role of autophagy in regulating inflammation and redox homeostasis in DS and discuss their crosslinks. A comprehensive elucidation of the roles of autophagy in DS offers novel insights for the development of therapeutic strategies aimed at aneuploidy-associated diseases.
    Keywords:  Down syndrome; autophagy; inflammation; redox homeostasis; stress signalling
    DOI:  https://doi.org/10.3389/fphar.2024.1491563
  51. Front Cell Infect Microbiol. 2024 ;14 1460604
    Effect of natural products on host cell autophagy induced by Influenza A virus infection.
    Xiaopan Liu, Qingsen Wang.
      Influenza A virus (IAV) can cause seasonal epidemics and global pandemics, posing serious threats to public health, making a deeper understanding of its biological characteristics and effective countermeasure strategies essential. Autophagy not only maintains cellular homeostasis but also plays an important role in host defense against IAV infection. However, the relationship between IAV and autophagy is complex, and effective antiviral drugs are not yet available. Natural products have shown excellent potential in disease control due to their diversity and multi-targeting. This review focuses on the relationship between IAV and autophagy and discusses the potential of targeting autophagic pathways for the development of new antiviral therapies. Particularly, the use of plant extracts as autophagy modulators has garnered attention due to their non-toxic nature and cost-effectiveness, which provides strong support for the development of future antiviral drugs that can help to inhibit viral infections and slow down disease progression.
    Keywords:  Influenza A virus; antiviral therapies; autophagy; plant extracts; viral infections
    DOI:  https://doi.org/10.3389/fcimb.2024.1460604
  52. Int J Mol Sci. 2024 Oct 04. pii: 10707. [Epub ahead of print]25(19):
    Small Molecules Inducing Autophagic Degradation of Expanded Polyglutamine Protein through Interaction with Both Mutant ATXN3 and LC3.
    Te-Hsien Lin, Wan-Ling Chen, Shao-Fan Hsu, I-Cheng Chen, Chih-Hsin Lin, Kuo-Hsuan Chang, Yih-Ru Wu, Yi-Ru Chen, Ching-Fa Yao, Wenwei Lin, Guey-Jen Lee-Chen, Chiung-Mei Chen.
      Polyglutamine (polyQ)-mediated spinocerebellar ataxia (SCA), including SCA1, 2, 3, 6, 7, and 17, are caused by mutant genes with expanded CAG repeats, leading to the intracellular accumulation of aggregated proteins, the production of reactive oxygen species, and cell death. Among SCA, SCA3 is caused by a mutation in the ATXN3 (ataxin-3) gene. In a circumstance of polyQ aggregation, the autophagic pathway is induced to degrade the aggregated proteins, thereby suppressing downstream deleterious effects and promoting neuronal survival. In this study, we tested the effects of synthetic indole (NC009-1, -2, -3, -6) and coumarin (LM-022, -031) derivatives as chemical chaperones to assist mutant ATXN3-Q75 folding, as well as autophagy inducers to clear aggregated protein. Among the tested compounds, NC009-1, -2, and -6 and LM-031 interfered with Escherichia coli-derived ATXN3-Q75 aggregation in thioflavin T binding and filter trap assays. In SH-SY5Y cells expressing GFP-fused ATXN3-Q75, these compounds displayed aggregation-inhibitory and neurite growth-promoting potentials compared to untreated cells. Furthermore, these compounds activated autophagy by increasing the phosphatidylethanolamine-conjugated LC3 (microtubule associated protein 1 light chain 3)-II:cytosolic LC3-I ratio in these cells. A biochemical co-immunoprecipitation assay by using a mixture of HEK 293T cell lysates containing recombinant ATXN3-Q75-Venus-C-terminus (VC) or Venus-N-terminus (VN)-LC3 protein indicated that NC009-1 and -2 and LM-031 served as an autophagosome-tethering compound (ATTEC) to interact with ATXN3-Q75 and LC3, and the interaction was further confirmed by bimolecular fluorescence complementation analysis in cells co-expressing both ATXN3-Q75-VC and VN-LC3 proteins. The study results suggest the potential of NC009-1 and -2 and LM-031 as an ATTEC in treating SCA3 and, probably, other polyQ diseases.
    Keywords:  ATXN3; LC3; SCA3 therapeutics; autophagosome tethering; polyglutamine; venus-based BiFC
    DOI:  https://doi.org/10.3390/ijms251910707
  53. Int J Mol Sci. 2024 Sep 26. pii: 10381. [Epub ahead of print]25(19):
    Blockade of mTORC1 via Rapamycin Suppresses 27-Hydroxycholestrol-Induced Inflammatory Responses.
    Nakyung Kang, Jaesung Kim, Munju Kwon, Yonghae Son, Seong-Kug Eo, Ninib Baryawno, Byoung Soo Kim, Sik Yoon, Sae-Ock Oh, Dongjun Lee, Koanhoi Kim.
      Atherosclerosis is characterized by the deposition and accumulation of extracellular cholesterol and inflammatory cells in the arterial blood vessel walls, and 27-hydroxycholesterol (27OHChol) is the most abundant cholesterol metabolite. 27OHChol is an oxysterol that induces immune responses, including immune cell activation and chemokine secretion, although the underlying mechanisms are not fully understood. In this study, we investigated the roles of the mechanistic target of rapamycin (mTOR) in 27HChol-induced inflammation using rapamycin. Treating monocytic cells with rapamycin effectively reduced the expression of CCL2 and CD14, which was involved with the increased immune response by 27OHChol. Rapamycin also suppressed the phosphorylation of S6 and 4EBP1, which are downstream of mTORC1. Additionally, it also alleviates the increase in differentiation markers into macrophage. These results suggest that 27OHChol induces inflammation by activating the mTORC1 signaling pathway, and rapamycin may be useful for the treatment of atherosclerosis-related inflammation involving 27OHchol.
    Keywords:  27-hydroxycholesterol; inflammation; mTOR; monocytic cells; rapamycin
    DOI:  https://doi.org/10.3390/ijms251910381
  54. FASEB J. 2024 Oct 15. 38(19): e70100
    Trophoblast-specific overexpression of adiponectin receptor 2 causes fetal growth restriction in pregnant mice.
    Jerad H Dumolt, Fredrick J Rosario, Kenneth Barentsen, Johann Urschitz, Theresa L Powell, Thomas Jansson.
      Maternal obesity in pregnancy is strongly associated with complications such as fetal overgrowth and infants of obese mothers have an increased risk to develop obesity, diabetes, and cardiovascular disease later in life. However, the underlying mechanisms are not well established. Circulating levels of adiponectin are low in obese pregnant women and maternal circulating adiponectin is negatively associated with birth weight. We have reported that normalizing maternal adiponectin in obese pregnant mice prevents placental dysfunction, fetal overgrowth, and programming of offspring cardio-metabolic disease. However, the mechanistic link between maternal adiponectin, placental function, and fetal growth remains to be established. We hypothesized that trophoblast-specific overexpression of the adiponectin receptor 2 (Adipor2) in healthy pregnant mice inhibits placental mTORC1 signaling and nutrient transport, resulting in fetal growth restriction. Using lentiviral transduction of blastocysts with a mammalian gene expression lentiviral vector for up-regulation of Adipor2 (Adipor2-OX), we achieved a ~ 3-fold increase in placenta Adipor2 mRNA levels and a 2-fold increase of the ADIPOR2 protein in the trophoblast plasma membrane. Placenta-specific Adipor2-OX increased placental peroxisome proliferator-activated receptor-α phosphorylation, ceramide synthase expression and ceramide concentrations. Furthermore, Adipor2-OX inhibited placental mTORC1 signaling and reduced in vivo placental transport of glucose and amino acids. Lastly, Adipor2-OX reduced fetal weight by 11%. These data provide mechanistic evidence that placental Adipor2 signaling directly affects fetal growth. We propose that low circulating adiponectin in maternal obesity causes fetal overgrowth and programs the offspring for cardio-metabolic disease mediated by a direct effect on placental function.
    Keywords:  PPARα; insulin signaling; mTOR; maternal–fetal exchange; placenta
    DOI:  https://doi.org/10.1096/fj.202302143R
  55. J Clin Invest. 2024 Oct 15. pii: e179633. [Epub ahead of print]134(20):
    Deficiency of parkin causes neurodegeneration and accumulation of pathological α-synuclein in monkey models.
    Rui Han, Qi Wang, Xin Xiong, Xiusheng Chen, Zhuchi Tu, Bang Li, Fei Zhang, Chunyu Chen, Mingtian Pan, Ting Xu, Laiqiang Chen, Zhifu Wang, Yanting Liu, Dajian He, Xiangyu Guo, Feng He, Peng Wu, Peng Yin, Yunbo Liu, Xiaoxin Yan, Shihua Li, Xiao-Jiang Li, Weili Yang.
      Parkinson's disease (PD) is characterized by age-dependent neurodegeneration and the accumulation of toxic phosphorylated α-synuclein (pS129-α-syn). The mechanisms underlying these crucial pathological changes remain unclear. Mutations in parkin RBR E3 ubiquitin protein ligase (PARK2), the gene encoding parkin that is phosphorylated by PTEN-induced putative kinase 1 (PINK1) to participate in mitophagy, cause early onset PD. However, current parkin-KO mouse and pig models do not exhibit neurodegeneration. In the current study, we utilized CRISPR/Cas9 technology to establish parkin-deficient monkey models at different ages. We found that parkin deficiency leads to substantia nigra neurodegeneration in adult monkey brains and that parkin phosphorylation decreases with aging, primarily due to increased insolubility of parkin. Phosphorylated parkin is important for neuroprotection and the reduction of pS129-α-syn. Consistently, overexpression of WT parkin, but not a mutant form that cannot be phosphorylated by PINK1, reduced the accumulation of pS129-α-syn. These findings identify parkin phosphorylation as a key factor in PD pathogenesis and suggest it as a promising target for therapeutic interventions.
    Keywords:  Aging; Neuroscience; Parkinson disease
    DOI:  https://doi.org/10.1172/JCI179633
  56. Anal Chim Acta. 2024 Nov 15. pii: S0003-2670(24)01046-8. [Epub ahead of print]1329 343245
    A supramolecular fluorescence probe that simultaneously responds to viscosity and G-quadruplex for autophagy detection.
    Ruiyang Bai, Dawei Yang, Ranran Sun, Xiufeng Zhang, Lei Shi, Jing Liu, Hongxia Sun, Li Yao, Yalin Tang.
       BACKGROUND: Autophagy, as an essential physiological process in eukaryotes, has been revealed to be closely related to aging and many major diseases. Real-time in situ imaging of autophagy processes in living cells is necessary for timely detection of autophagy defects and the development of treatment methods. Currently, many studies are dedicated to the design of autophagy probes, and various types of fluorescent probes for autophagy detection have been reported. However, most of them are single fluorescence signal outputs, which may lead to non-specific signals. Nowadays a reliable and sensitive autophagy monitoring probe is still essential.
    RESULTS: A supramolecular fluorescent probe was prepared via the controllable self-assembly of a thiacyanine dye named PTC for tracking autophagy in living cells. PTC was very sensitive to viscosity, and its aggregates were completely converted into monomers as viscosity increased. This process led to a significant increase of over 2000 times in the fluorescence intensity ratio between monomers and aggregates. PTC also exhibited selective affinity for G-quadruplex (G4) structure, which decomposed PTC aggregates into monomers, resulting in a fluorescence ratio increase of up to tens of folds. In living cells, PTC existed as aggregates in lysosomes, maintaining sensitivity to viscosity and G4s. In confocal imaging experiments, PTC sensitively responded to the induction and inhibition of cellular autophagy, displaying opposite changes in the monomer and aggregate fluorescent channels.
    SIGNIFICANCE: This work provides a reliable fluorescent probe for autophagy detection in live cells, which has the advantages of high sensitivity, low cost, and ease of use, making it have the potential for widespread application. This study also offers a new strategy for designing autophagy probes with both high sensitivity and high specificity.
    Keywords:  Autophagy; Dual-signal; G-quadruplex; Supramolecular fluorescence probe; Viscosity
    DOI:  https://doi.org/10.1016/j.aca.2024.343245
  57. Reprod Toxicol. 2024 Oct 12. pii: S0890-6238(24)00198-9. [Epub ahead of print] 108731
    AKT/mTOR-mediated autophagic signaling is associated with TCDD-induced cleft palate.
    Yaxin Zhang, Dongliang Xu, Shuaixing Song, Guoxu Wang, Hexin Su, Yang Wu, Yuwei Zhang, Hongyan Liu, Qingfu Li, Xiangdong Wang, Zengli Yu, Xiaozhuan Liu.
      In utero exposure to the environmental contaminant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can contribute to high rates of cleft palate (CP) formation, but the mechanistic basis for these effects remains uncertain. Here, multi-omics-based metabolomic and transcriptomic analyses were employed to characterize the etiological basis for TCDD-induced CP on gestational day 14.5 (GD14.5). These analyses revealed that TCDD-induced CP formation is associated with calcium, MAPK, PI3K-Akt, and mTOR pathway signaling. PI3K-Akt and mTOR signaling activity is closely linked with the maintenance of cellular proliferation and survival. Moreover, mTOR-mediated regulation of autophagic activity is essential for ensuring an appropriate balance between metabolic activity and growth. Murine embryonic palatal mesenchymal (MEPM) cell proliferation was thus characterized, autophagic activity in these cells was evaluated through electron microscopy and western immunoblotting was used to compare the levels of autophagy- and AKT/mTOR-related protein between the control and TCDD groups on GD14.5. These analyses indicated that MEPM cell proliferative and autophagic activity was inhibited in response to TCDD exposure with the concomitant activation of AKT/mTOR signaling, in line with the multi-omics data. Together, these findings suggested that following TCDD exposure, the activation of AKT/mTOR-related autophagic signaling may play a role in the loss of appropriate palatal cell homeostasis, culminating in the incidence of CP.
    Keywords:  AKT/mTOR signaling; Autophagy; Cleft palate; MEPM cell; Multi-omics; TCDD
    DOI:  https://doi.org/10.1016/j.reprotox.2024.108731
  58. Placenta. 2024 Oct 01. pii: S0143-4004(24)00662-3. [Epub ahead of print]158 89-101
    Circular RNA hsa_circ_0081343 modulates trophoblast autophagy through Rbm8a nuclear translocation.
    Linmei Zheng, Rong Tang, Junbo Fang, Haoyue Hu, Fiaz Ahmad, Qiong Tang, Jinfu Liu, Mei Zhong, Jing Li.
       INTRODUCTION: Fetal growth restriction (FGR) is a kind of obstetric complication that seriously endangers fetal life. Recent studies reported significant reduction of hsa_circ_0081343 in human placenta developed in FGR and is involved in cell migration, invasion, and apoptosis of trophoblast by acting as microRNA sponges. Autophagy is required for invasion of trophoblast cells and for vascular remodeling during placentation. In this study, we aimed to explore the mechanistic link between hsa_circ_0081343 and autophagy.
    METHODS: We investigated the interactions between hsa_circ_0081343 and RNA-binding proteins were studied by RNA pull-down assay, mass spectrometry and RNA immunoprecipitation assay. The mechanism of nuclear translocation of Rbm8a were assessed by reverse transcription-quantitative PCR, Western blot, immunofluorescence and Co-Immunoprecipitation. Western blot, immunofluorescence and transmission electron microscopy were performed to elucidate the mechanism underlying hsa_circ_0081343 and/or Rbm8a mediated regulation of autophagy.
    RESULTS: hsa_circ_0081343 served as an RNA-binding protein (RBP) sponge. RNA binding motif protein 8A (Rbm8a) was directly bound to hsa_circ_0081343 in the cytoplasm, while knockdown of hsa_circ_0081343 facilitated Rbm8a localization in the nucleus. We also identified Rbm8a as a potential import cargo for Importin13 (Ipo13), which transported Rbm8a across the nuclear membrane into the nucleus. Ipo13 recognized Rbm8a via a functional nuclear localization signal (NLS). Furthermore, the mechanistic study revealed that hsa_circ_0081343-mediated nuclear translocation of Rbm8a activated trophoblast autophagy.
    DISCUSSION: Our results suggest that hsa_circ_0081343 could bind to RBP and the interaction between hsa_circ_0081343 and Rbm8a participate in regulating autophagy. These findings offer novel molecular targets and insights for a potential therapeutic strategy against FGR.
    Keywords:  Autophagy; Fetal growth restriction; Ipo13; Rbm8a; hsa_circ_0081343
    DOI:  https://doi.org/10.1016/j.placenta.2024.09.019
  59. Cell Signal. 2024 Oct 16. pii: S0898-6568(24)00449-2. [Epub ahead of print] 111474
    HKDC1 promotes autophagy and proliferation in pancreatic adenocarcinoma through interaction with PARP1 and poly(ADP-ribosyl)ation.
    Qiang Pang, Shansong Huang, Huiying Wang, Jiaqing Cao.
       BACKGROUND: HKDC1 has been shown to play an important role in promoting malignant progression of pancreatic adenocarcinoma (PAAD), but the exact mechanism is unclear. This study aimed to investigate the function of HKDC1 in autophagy activation and cell proliferation.
    METHODS: By GSEA analysis of TCGA data of PAAD, we found that HKDC1 was closely associated with autophagy. We evaluated the effects of HKDC1 knockdown and overexpression on the expression of LC3B, an autophagy marker, and Cyclin D1 and PCNA, cell proliferation-associated proteins, by Western blotting (WB) and transmission electron microscopy (TEM) analysis.
    RESULTS: Knockdown of HKDC1 decreased LC3B expression and led to a decrease in the accumulation of autophagic vesicles and autophagic lysosomes, while overexpression of HKDC1 produced the opposite effect. Meanwhile, HKDC1 overexpression significantly promoted the proliferation of PAAD cells and increased the expression levels of Cyclin D1 and PCNA. Further studies showed that HKDC1 enhanced PARP1's own poly ADP-ribosylation (PARylation) activity by interacting with PARP1, which in turn promoted autophagy. In vivo experiments showed that knockdown of HKDC1 significantly inhibited the growth of pancreatic cancer cells in nude mice in vivo, reduced tumor volume and weight, and down-regulated the expression of PARP1, LC3, Cyclin D1 and PCNA.
    CONCLUSION: HKDC1 plays a critical role in the malignant progression of PAAD by activating autophagy and promoting cell proliferation. Our findings suggest that targeting HKDC1 and its downstream signaling pathways may provide novel strategies for PAAD treatment.
    Keywords:  Autophagy; HKDC1; PARP1; Pancreatic adenocarcinoma; Poly(ADP-ribosyl)ation
    DOI:  https://doi.org/10.1016/j.cellsig.2024.111474
  60. CNS Neurosci Ther. 2024 Oct;30(10): e70036
    GLS2 reduces the occurrence of epilepsy by affecting mitophagy function in mouse hippocampal neurons.
    Yuan Gao, Limin Ma, Jinxian Yuan, Yunyi Huang, Yuenan Ban, Peng Zhang, Dandan Tan, Minxue Liang, Zhipeng Li, Chen Gong, Tao Xu, Xiaolan Yang, Yangmei Chen.
       BACKGROUND: Altered mitophagy has been observed in various neurological disorders, such as epilepsy. The role of mitophagy in causing neuronal damage during epileptic episodes is significant, and recent research has indicated that GLS2 plays a crucial role in regulating autophagy. However, exactly how GLS2 affects epilepsy is still unclear.
    AIMS: To investigate the expression and distribution characteristics of GLS2 in epilepsy, and then observed the changes in behavior and electrophysiology caused by overexpression of GLS2 in epileptic mice, and determined whether GLS2 regulated seizure-like changes in the mouse model through the protective mechanism of mitophagy.
    RESULTS: The expression of GLS2 in a kainic acid (KA)-induced epileptic mouse model and aglutamate-inducedneuronal excitatory damage in HT22 cells model was downregulation. In brief, overexpression of GLS2 can alleviate epileptic activity. Subsequently, we demonstrated that GLS2 interacts with mitophagy-related proteins in a KA-induced epilepsy mouse model. Mechanistically, overexpression of GLS2 inhibited mitophagy in epileptic mice, downregulating the expression of LC3 and reducing ROS production.
    CONCLUSIONS: This study proves the GLS2 expression pattern is abnormal in epileptic mice. The function of mitophagy in hippocampal neurons is affected by GLS2, and overexpression of GLS2 can reduce the occurrence of seizure-like events (SLEs) by altering mitophagy function. Thus, GLS2 might control seizures, and our findings provide a fresh avenue for antiepileptic treatment and offer novel insights into treating and preventing epilepsy.
    Keywords:  GLS2; epilepsy; mitophagy; neuron; reactive oxygen species (ROS); seizure
    DOI:  https://doi.org/10.1111/cns.70036
  61. Hum Mol Genet. 2024 Oct 15. pii: ddae143. [Epub ahead of print]
    Ceramide lowering rescues respiratory defects in a Drosophila model of acid sphingomyelinase deficiency.
    Alexander J Hull, Magda L Atilano, Jenny Hallqvist, Wendy Heywood, Kerri J Kinghorn.
      Types A and B Niemann-Pick disease (NPD) are inherited multisystem lysosomal storage disorders due to mutations in the SMPD1 gene. Respiratory dysfunction is a key hallmark of NPD, yet the mechanism for this is underexplored. SMPD1 encodes acid sphingomyelinase (ASM), which hydrolyses sphingomyelin to ceramide and phosphocholine. Here, we present a Drosophila model of ASM loss-of-function, lacking the fly orthologue of SMPD1, dASM, modelling several aspects of the respiratory pathology of NPD. dASM is expressed in the late-embryonic fly respiratory network, the trachea, and is secreted into the tracheal lumen. Loss of dASM results in embryonic lethality, and the tracheal lumen fails to fill normally with gas prior to eclosion. We demonstrate that the endocytic clearance of luminal constituents prior to gas-filling is defective in dASM mutants, and is coincident with autophagic, but not lysosomal defects, in late stage embryonic trachea. Finally, we show that although bulk sphingolipids are unchanged, dietary loss of lipids in combination with genetic and pharmacological block of ceramide synthesis rescues the airway gas-filling defects. We highlight myriocin as a potential therapeutic drug for the treatment of the developmental respiratory defects associated with ASM deficiency, and present a new NPD model amenable to genetic and pharmacological screens.
    Keywords:   Drosophila ; SMPD1 ; dASM ; Niemann-Pick; lysosomal storage disorder; lysosome; sphingolipid
    DOI:  https://doi.org/10.1093/hmg/ddae143
  62. Int J Mol Sci. 2024 Sep 28. pii: 10476. [Epub ahead of print]25(19):
    Hyperbaric Treatment Stimulates Chaperone-Mediated Macroautophagy and Autophagy in the Liver Cells of Healthy Female Rats.
    Agnieszka Pedrycz, Mariusz Kozakiewicz, Mansur Rahnama, Marek Kos, Ewelina Grywalska, Marietta Bracha, Anna Grzywacz, Iwona Bojar.
      The role of autophagy goes far beyond the elimination of damaged cellular components and the quality control of proteins. It also cleanses cells from inclusions, including pathogenic viruses, and provides energy-forming components. The liver, which is an organ with increased metabolism, is made up of cells that are particularly vulnerable to damage. Therefore, detoxification of liver cells in the process of autophagy has become a very important issue clinically. The aim of this study was an immunohistochemical evaluation of proteins activated in rat liver cells at different stages of hyperbaric autophagy. The rats used for the study were randomly divided into six equivalent groups-three control groups and three experimental groups. Animals from the experimental groups were subjected to hyperbaric treatment in a hyperbaric chamber, with a pressure of 1.6 ATA for 120 min. They breathed atmospheric air. Rats were decapitated within 5 or 10 days after removal from the chamber. Immunohistochemical reactions with beclin 1, LC3B, RAB7, and HSC73 proteins were carried out on preparations made from liver slices. A three-step labeled streptavidin-biotin detection method of paraffin blocks (LSAB three-step) was used for immunohistochemical research. The results were evaluated using computer programs for morphometric analysis of microscopic images by calculating the mean surface areas occupied by a positive immunohistochemical reaction in individual groups for all antibodies tested. Increased closure of substrates in the autophagosome (beclin 1) induced late endosome transport and accelerated autophagosome maturation process (RAB7). Furthermore, a larger number of autophagosomes (LC3B) was observed in liver cells immediately after the cessation of hyperbaric activity; however, this decreased after 5 days. During this time, chaperone-mediated autophagy (HSC73) was observed on a larger scale. This means that increased macroautophagy induced by hyperbaric treatment weakens with time that has elapsed since the cessation of high pressure, whereas similarly induced chaperone-mediated autophagy intensifies over time.
    Keywords:  autophagy; chaperones (HSC73); hyperbaric treatment; liver; viruses
    DOI:  https://doi.org/10.3390/ijms251910476
  63. Anal Chem. 2024 Oct 17.
    Spatially Selective Self-Amplified Imaging of Chemotherapy-Induced Cancer Senescence via Reversal of Impaired Ferritinophagy.
    Yuqi Xie, Xiyuan Luo, Xinjia Di, Jili Li, Yinghao Xia, Linlin Wang, Yanlan Liu.
      Real-time monitoring of chemotherapy-induced senescence (CIS) in cancer remains a challenging task that would lead to new insights into the adaptive mechanisms of cancer therapy and provide guidance for cancer management. Here, we designed a tailor-made nanoprobe capable of imaging CIS in a sequential activation and self-amplified manner by reversing senescence-related impaired ferritinophagy. It contains an amphipathic polymer as a spatially responsive vehicle, a Fe2+-activable dye as the reporter, and an autophagy inducer as the signal amplifier. Owing to metabolic changes, the nanoprobe preferentially enriches in senescent cancer cells, leading to in situ activation and fluorescence switching of the reporter by labile Fe2+. Meanwhile, the inducer restores ferritinophagy and promotes autophagic degradation of accumulated ferritin, facilitating conversion of ferritin-bound iron into Fe2+ for amplified imaging in senescent cancer cells yet keeping inert in nonsenescent cells. Of note, the accumulation and activation of the nanoprobe and sustained ferritin degradation occur at the same subcellular location, thus minimizing the diffusion process-induced nonspecific responses. The feasibility of this strategy is successfully demonstrated in both living cells and animal models. This work offers a new way for therapeutic evaluation and a basic understanding of the roles of senescence in cancer treatment.
    DOI:  https://doi.org/10.1021/acs.analchem.4c02543
  64. Nat Chem Biol. 2024 Oct 16.
    Methylarginine targeting chimeras for lysosomal degradation of intracellular proteins.
    Laurence J Seabrook, Carolina N Franco, Cody A Loy, Jaida Osman, Callie Fredlender, Jan Zimak, Melissa Campos, Steven T Nguyen, Richard L Watson, Samantha R Levine, Marian F Khalil, Kaelyn Sumigray, Darci J Trader, Lauren V Albrecht.
      A paradigm shift in drug development is the discovery of small molecules that harness the ubiquitin-proteasomal pathway to eliminate pathogenic proteins. Here we provide a modality for targeted protein degradation in lysosomes. We exploit an endogenous lysosomal pathway whereby protein arginine methyltransferases (PRMTs) initiate substrate degradation via arginine methylation. We developed a heterobifunctional small molecule, methylarginine targeting chimera (MrTAC), that recruits PRMT1 to a target protein for induced degradation in lysosomes. MrTAC compounds degraded substrates across cell lines, timescales and doses. MrTAC degradation required target protein methylation for subsequent lysosomal delivery via microautophagy. A library of MrTAC molecules exemplified the generality of MrTAC to degrade known targets and neo-substrates-glycogen synthase kinase 3β, MYC, bromodomain-containing protein 4 and histone deacetylase 6. MrTAC selectively degraded target proteins and drove biological loss-of-function phenotypes in survival, transcription and proliferation. Collectively, MrTAC demonstrates the utility of endogenous lysosomal proteolysis in the generation of a new class of small molecule degraders.
    DOI:  https://doi.org/10.1038/s41589-024-01741-y
  65. Eur J Histochem. 2024 Oct 15. 68(4):
    Irisin suppresses PDGF-BB-induced proliferation of vascular smooth muscle cells in vitro by activating AMPK/mTOR-mediated autophagy.
    Fenqiang Qi, Yuxin Deng, Wei Huang, Yanli Cai, Kelin Hong, Shui Xiang.
      Restenosis is a pivotal factor that restricts the efficacy of coronary artery bypass grafting. Inhibition of vascular smooth muscle cells (VSMCs) proliferation can improve intimal hyperplasia and lumen stenosis. Irisin, a polypeptide secreted by muscle cells, has been demonstrated to have a protective role in various cardiovascular diseases. However, the effect and mechanism of irisin on VSMCs proliferation and phenotype switching remain unclear. Cell proliferation ability was assessed using the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and 5-ethynyl-2'-deoxyuridine (EdU) incorporation. Cell cycle analysis was performed using flow cytometry, while expression levels of contractile and synthesis-related proteins were determined through RT-qPCR and Western blot. The VSMCs were infected with an adenovirus carrying GFP-LC3, and the proportion of cells showing positive expression was assessed. Additionally, the formation of autophagic lysosomes in cells was observed through transmission electron microscopy. In this study, we have demonstrated the inhibitory effects of irisin on the proliferation and phenotypic transition of platelet-derived growth factor-BB (PDGF-BB)-induced VSMCs. More importantly, we have discovered that irisin can activate the AMP-activated protein kinase/mammalian target of rapamycin (AMPK/mTOR) signaling pathway to mediate autophagy in PDGF-BB-induced VSMCs. The inhibitory effect of irisin on PDGF-BB-induced VSMCs proliferation was significantly attenuated by the AMPK inhibitor, Compound C. Conversely the mTOR inhibitor, rapamycin further enhanced the inhibitory effect of irisin on PDGF-BB induced VSMCs proliferation. In conclusion, our findings suggest that irisin effectively suppresses the aberrant proliferation of VSMCs following PDGF-BB stimulation by modulating autophagy levels through the AMPK/mTOR signaling pathway.
    DOI:  https://doi.org/10.4081/ejh.2024.4104
  66. Int Immunopharmacol. 2024 Oct 16. pii: S1567-5769(24)01897-6. [Epub ahead of print]143(Pt 2): 113375
    S100A8 knockdown activates the PI3K/AKT signaling pathway to inhibit microglial autophagy and improve cognitive impairment mediated by chronic sleep deprivation.
    Yanhong Xiong, Weidong Liang, Xifeng Wang, Hong Zhu, Pengcheng Yi, Gen Wei, Hailin Liu, Yue Lin, Lieliang Zhang, Jun Ying, Fuzhou Hua.
       OBJECTIVE: Cognitive dysfunction is one of the major symptoms of chronic sleep deprivation (CSD). Abnormal autophagy and apoptosis are thought to be important mechanisms. S100 Calcium Binding Protein A8 (S100A8) plays a key role in autophagy and apoptosis of microglia. This study investigated whether S100A8 knockdown can effectively inhibit aberrant autophagy in microglia and improve cognitive function by activating the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway under CSD conditions.
    METHODS: CSD mouse models and BV2 cell autophagy models were established in vivo and in vitro. Transcriptome sequencing was used to determine the key regulator related to autophagy. The Morris water maze test was used to evaluate the cognitive behavior of the mice. RT-qPCR and western blot were conducted to examine S100A8 expression and autophagy signalling. HE, TUNEL, transmission electron microscopy, immunofluorescence, and histochemistry were performed to detect pathological changes, neuronal autophagy, apoptosis, or positive cells in hippocampal tissues, respectively.
    RESULTS: Transcriptome sequencing showed that S100A8 was significantly elevated in CSD mice, and fluorescence colocalization results further suggested that S100A8 mainly colocalizes with microglia. In vivo studies revealed that knockdown of S100A8 alleviated CSD-induced cognitive impairment in mice. Through further mechanistic investigations employing both in vivo and in vitro models, we demonstrated that silencing S100A8 can activate the PI3K/AKT pathway, thereby reducing CSD-induced abnormal autophagy and apoptosis in microglia. Aberrant autophagy and apoptosis in microglia were reversed with the PI3K/AKT pathway inhibitor LY294002.
    CONCLUSION: The S100A8/PI3K/AKT axis plays a crucial role in chronic sleep deprivation-mediated autophagy and apoptosis in microglia.
    Keywords:  Apoptosis; Autophagy; CSD; Cognitive impairment; PI3K/AKT; S100A8
    DOI:  https://doi.org/10.1016/j.intimp.2024.113375
  67. Cell Biochem Biophys. 2024 Oct 18.
    Proteostasis and Its Role in Disease Development.
    Manisha Shukla, Mahesh Narayan.
      Proteostasis (protein homeostasis) refers to the general biological process that maintains the proper balance between the synthesis of proteins, their folding, trafficking, and degradation. It ensures proteins are functional, locally distributed, and appropriately folded inside cells. Genetic information enclosed in mRNA is translated into proteins. To ensure newly synthesized proteins take on the exact three-dimensional conformation, molecular chaperones assist in proper folding. Misfolded proteins can be refolded or targeted for elimination to stop aggregation. Cells utilize different degradation pathways, for instance, the ubiquitin-proteasome system, the autophagy-lysosome pathway, and the unfolded protein response, to degrade unwanted or damaged proteins. Quality control systems of the cell monitor the folding of proteins. These checkpoint mechanisms are aimed at degrading or refolding misfolded or damaged proteins. Under stress response pathways, such as heat shock response and unfolded protein response, which are triggered under conditions that perturb proteostasis, the capacity for folding is increased, and degradation pathways are activated to help cells handle stressful conditions. The deregulation of proteostasis is implicated in a variety of illnesses, comprising cancer, metabolic diseases, cardiovascular diseases, and neurological disorders. Therapeutic strategies with a deeper insight into the mechanism of proteostasis are crucial for the treatment of illnesses linked with proteostasis and to support cellular health. Thus, proteostasis is required not only for the maintenance of cellular homeostasis and function but also for proper protein function and prevention of injurious protein aggregation. In this review, we have covered the concept of proteostasis, its mechanism, and how disruptions to it can result in a number of disorders.
    Keywords:  Diseases; Heat shock protein; Misfolded protein; Protein degradation pathway; Proteostasis
    DOI:  https://doi.org/10.1007/s12013-024-01581-6
  68. Front Pharmacol. 2024 ;15 1441105
    Formononetin triggers ferroptosis in triple-negative breast cancer cells by regulating the mTORC1/SREBP1/SCD1 pathway.
    Dong Xie, Yulang Jiang, Huan Wang, Lingyi Zhu, Shuangqin Huang, Sheng Liu, Weihong Zhang, Tian Li.
       Introduction: Triple-negative breast cancer (TNBC) is the most malignant type of breast cancer, and its prognosis is still the worst. It is necessary to constantly explore the pathogenesis and effective therapeutic targets of TNBC. Formononetin is an active ingredient with anti-tumor effects that we screened earlier. The main purpose of this study is to elucidate mechanism of the inhibitory effect of Formononetin on TNBC.
    Methods: We conducted experiments through both in vivo and in vitro methodologies. The in vivo experiments utilized a nude mice xenotransplantation model, while the in vitro investigations employed two breast cancer cell lines, MDA-MB-231 and MDA-MB-468. Concurrently, ferroptosis associated proteins, lipid peroxide levels, and proteins related to the rapamycin complex 1 were analyzed in both experimental settings.
    Results: In our study, Formononetin exhibits significant inhibitory effects on the proliferation of triple TNBC, both in vivo and in vitro. Moreover, it elicits an increase in lipid peroxide levels, downregulates the expression of ferroptosis-associated proteins GPX4 and xCT, and induces ferroptosis in breast cancer cells. Concurrently, Formononetin impedes the formation of the mammalian target of rapamycin complex 1 (mTORC1) and suppresses the expression of downstream Sterol regulatory element-binding protein 1(SREBP1). The utilization of breast cancer cells with SREBP1 overexpression or knockout demonstrates that Formononetin induces ferroptosis by modulating the mTORC1-SREBP1 signaling axis.
    Discussion: In conclusion, this study provides evidence that Formononetin exerts an anti-proliferative effect on triple-negative breast cancer by inducing ferroptosis. Moreover, the mTORC1-SREBP1 signal axis is identified as the primary mechanism through which formononetin exerts its therapeutic effects. These findings suggest that formononetin holds promise as a potential targeted drug for clinical treatment of TNBC.
    Keywords:  Formononetin; ferroptosis; mammalian target of rapamycin complex1; sterol regulatory element-binding protein 1; triple-negative breast cancer
    DOI:  https://doi.org/10.3389/fphar.2024.1441105
  69. Acta Physiol (Oxf). 2024 Oct 18. e14243
    Histone deacetylase 6 inhibition promotes microtubule acetylation and facilitates autophagosome-lysosome fusion in dystrophin-deficient mdx mice.
    Akanksha Agrawal, Erin L Clayton, Courtney L Cavazos, Benjamin A Clayton, George G Rodney.
       AIM: Duchenne muscular dystrophy is a progressive muscle-wasting disease caused by mutations in the dystrophin gene. Despite progress in dystrophin-targeted gene therapies, it is still a fatal disease requiring novel therapeutics that can be used synergistically or alternatively to emerging gene therapy. Defective autophagy and disorganized microtubule networks contribute to dystrophic pathogenesis, yet the mechanisms by which microtubule alterations regulate autophagy remain elusive. The present study was designed to uncover possible mechanisms underpinning the role of microtubules in regulating autophagy in dystrophic mice.
    METHODS: Mdx mice were also supplemented with Tubastatin A, a pharmacological inhibitor of histone deacetylase 6, and pathophysiology was assessed. Mdx mice with a genetic deletion of the Nox-2 scaffolding subunit p47phox were used to assess redox dependence on tubulin acetylation.
    RESULTS: Our data show decreased acetylation of α-tubulin with enhanced histone deacetylase 6 expression. Tubastatin A increases tubulin acetylation and Q-SNARE complex formation but does not alter microtubule organization or density, indicating improved autophagosome-lysosome fusion. Tubastatin A increases the acetylation of peroxiredoxin and protects it from hyper-oxidation, hence modulating intracellular redox status in mdx mice. Tubastatin A reduces muscle damage and enhances force production. Genetic down regulation of Nox2 activity in the mdx mice promotes autophagosome maturation but not autolysosome formation.
    CONCLUSION: Our data highlight that autophagy is differentially regulated by redox and acetylation in mdx mice. By improving autophagy through promoting tubulin acetylation, Tubastatin A decreases the dystrophic phenotype and improves muscle function, suggesting a great potential for clinical translation and treating dystrophic patients.
    Keywords:  Duchenne muscular dystrophy; acetylation; autolysosome; autophagy; microtubule; redox
    DOI:  https://doi.org/10.1111/apha.14243
  70. FASEB J. 2024 Oct 31. 38(20): e70099
    Plasma membrane repair defect in Alzheimer's disease neurons is driven by the reduced dysferlin expression.
    Hannah R Bulgart, Miguel A Lopez Perez, Alexis Tucker, Gianni N Giarrano, Kassidy Banford, Olivia Miller, Sidney W G Bonser, Loren E Wold, Douglas Scharre, Noah Weisleder.
      Alzheimer's disease (AD) is the most common neurodegenerative disease, and a defect in neuronal plasma membrane repair could exacerbate neurotoxicity, neuronal death, and disease progression. In this study, application of AD patient cerebrospinal fluid (CSF) and recombinant human Aβ to otherwise healthy neurons induces defective neuronal plasma membrane repair in vitro and ex vivo. We identified Aβ as the biochemical component in patient CSF leading to compromised repair capacity and depleting Aβ rescued repair capacity. These elevated Aβ levels reduced expression of dysferlin, a protein that facilitates membrane repair, by altering autophagy and reducing dysferlin trafficking to sites of membrane injury. Overexpression of dysferlin and autophagy inhibition rescued membrane repair. Overall, these findings indicate an AD pathogenic mechanism where Aβ impairs neuronal membrane repair capacity and increases susceptibility to cell death. This suggests that membrane repair could be therapeutically targeted in AD to restore membrane integrity and reduce neurotoxicity and neuronal death.
    Keywords:  Alzheimer's disease; autophagy; dysferlin; membrane repair; neurodegeneration
    DOI:  https://doi.org/10.1096/fj.202401731RR
  71. Front Aging Neurosci. 2024 ;16 1480502
    Updated insights into the NLRP3 inflammasome in postoperative cognitive dysfunction: emerging mechanisms and treatments.
    Tian Wang, Guangwei Sun, Bingdong Tao.
      Postoperative cognitive dysfunction (POCD) poses a significant threat to patients undergoing anesthesia and surgery, particularly elderly patients. It is characterized by diminished cognitive functions post surgery, such as impaired memory and decreased concentration. The potential risk factors for POCD include age, surgical trauma, anesthetic type, and overall health condition; however, the precise mechanisms underlying POCD remain elusive. Recent studies suggest that neuroinflammation might be a primary pathogenic factor. NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasomes are implicated in exacerbating POCD by promoting the release of inflammatory factors and proteins that initiate pyroptosis, further influencing the disease process. The regulation of NLRP3 inflammasome activity, including its activation and degradation, is tightly controlled through multiple pathways and mechanisms. In addition, autophagy, a protective mechanism, regulates the NLRP3 inflammasome to control the progression of POCD. This review reviews recent findings on the role of the NLRP3 inflammasome in POCD pathogenesis and discusses therapeutic strategies aimed at reducing NLRP3 sources, inhibiting cellular pyroptosis, and enhancing autophagy.
    Keywords:  NLRP3; POCD; autophagy; autophagy POCD; inflammasomes; neuroinflammation; pyroptosis
    DOI:  https://doi.org/10.3389/fnagi.2024.1480502
  72. J Cell Biol. 2024 Dec 02. pii: e202309090. [Epub ahead of print]223(12):
    Tip60-mediated Rheb acetylation links palmitic acid with mTORC1 activation and insulin resistance.
    Zengqi Zhao, Qiang Chen, Xiaojun Xiang, Weiwei Dai, Wei Fang, Kun Cui, Baolin Li, Qiangde Liu, Yongtao Liu, Yanan Shen, Yueru Li, Wei Xu, Kangsen Mai, Qinghui Ai.
      Excess dietary intake of saturated fatty acids (SFAs) induces glucose intolerance and metabolic disorders. In contrast, unsaturated fatty acids (UFAs) elicit beneficial effects on insulin sensitivity. However, it remains elusive how SFAs and UFAs signal differentially toward insulin signaling to influence glucose homeostasis. Here, using a croaker model, we report that dietary palmitic acid (PA), but not oleic acid or linoleic acid, leads to dysregulation of mTORC1, which provokes systemic insulin resistance. Mechanistically, we show that PA profoundly elevates acetyl-CoA derived from mitochondrial fatty acid β oxidation to intensify Tip60-mediated Rheb acetylation, which triggers mTORC1 activation by promoting the interaction between Rheb and FKBPs. Subsequently, hyperactivation of mTORC1 enhances IRS1 serine phosphorylation and inhibits TFEB-mediated IRS1 transcription, inducing impairment of insulin signaling. Collectively, our results reveal a conserved molecular insight into the mechanism by which Tip60-mediated Rheb acetylation induces mTORC1 activation and insulin resistance under the PA condition, which may provide therapeutic avenues to intervene in the development of T2D.
    DOI:  https://doi.org/10.1083/jcb.202309090
  73. Int J Mol Sci. 2024 Sep 27. pii: 10415. [Epub ahead of print]25(19):
    The Antidepressant Drug Amitriptyline Affects Human SH-SY5Y Neuroblastoma Cell Proliferation and Modulates Autophagy.
    Annagrazia Adornetto, Maria Luisa Laganà, Andrea Satriano, Ester Licastro, Maria Tiziana Corasaniti, Giacinto Bagetta, Rossella Russo.
      Amitriptyline is a tricyclic antidepressant commonly used for depressive disorders and is prescribed off-label for several neurological conditions like neuropathic pain, migraines and anxiety. Besides their action on the reuptake of monoaminergic neurotransmitters, tricyclic antidepressants interact with several additional targets that may contribute to either therapeutic or adverse effects. Here, we investigated the effects of amitriptyline on proliferation and autophagy (i.e., an evolutionarily conserved catabolic pathway responsible for the degradation and recycling of cytoplasmic material) in human SH-SY5Y neuroblastoma cell cultures. The dose and time-dependent upregulation of the autophagy marker LC3II and the autophagy receptor p62, with the accumulation of LAMP1 positive compartments, were observed in SH-SY5Y cells exposed to the amitriptyline. These effects were accompanied by reduced cell viability and decreased clonogenic capacity, without a significant induction of apoptosis. Decrease viability and clonogenic activity were still observed in autophagy deficient Atg5-/- MEF and following pre-treatment of SH-SY5Y culture with the autophagy inhibitor chloroquine, suggesting that they were independent from autophagy modulation. Our findings demonstrate that amitriptyline acts on pathways crucial for cell and tissue homeostasis (i.e., autophagy and proliferation) and pose the basis for further studies on the potential therapeutic application of amitriptyline, as well as the consequences of its use for long-term treatments.
    Keywords:  amitriptyline; antidepressant; apoptosis; autophagy; cell proliferation; cytotoxicity; neuroblastoma
    DOI:  https://doi.org/10.3390/ijms251910415
  74. Ecotoxicol Environ Saf. 2024 Oct 12. pii: S0147-6513(24)01247-8. [Epub ahead of print]286 117171
    Involvement of autophagy and gut dysbiosis in ambient particulate matter-induced colonic inflammation.
    Hsien-Jen Cheng, Wei-Lun Hsu, Pinpin Lin, Yu-Cheng Chen, Tang-Huang Lin, Shih-Shuan Fang, Ming-Hsien Tsai, Yen-Ju Lin, Shuo-Ping Wang, Hsin Chen, Ming-Shiou Jan, Yueh-Hsia Luo.
      Ambient fine particulate matter (PM2.5), a vital environmental toxicant, not only adversely affects the cardiovascular and respiratory systems but also potentially exhibits an association with intestinal inflammation and colorectal cancer (CRC). The underlying molecular mechanisms of PM2.5 impacts on CRC are still unclear. In this study, we utilized collected ambient PM2.5 and standard reference material SRM2786 to investigate the toxic effects on the colon through in vivo chronic exposure mouse and in vitro cell culture models. We employed a chronic mouse exposure model to clarify the colonic injury and gut microbiome biomarkers. Prolonged exposure to PM2.5 via oropharyngeal aspiration led to a significant rise in colonic epithelial proliferation and reduced colon length in mice. It triggered characteristics indicative of gut microbiota dysbiosis linked to inflammatory bowel disease. The gut microbiome alternations may serve as a biomarker indicating the colonic health impacts of PM2.5 exposure. PM2.5 and SRM2786-induced cytotoxicity manifested as autophagy dysregulation-mediated abnormal proliferation, IL-8 production, p62/SQSTM1 accumulation, and lysosomal membrane damage in human colon cells WiDr and Caco-2. Both PM2.5 and SRM2786 exposures led to the accumulation of p62/SQSTM1 and compromised lysosomal membrane integrity, showing impaired autophagic flux in WiDr and Caco-2 cells. Finally, we examined the correlations between atmospheric PM2.5 data and biomarkers of colonic inflammation in human population. The serum level of IL-8 was significantly correlated with regional anthropogenic pollutants. In conclusion, our findings elucidate that ambient PM2.5 exhibits adverse effects on colon health manifested as inflammation, aberrant proliferation, and gut dysbiosis, potentially mediated through autophagy dysregulation, thereby highlighting the importance of further research on the impact of environmental pollutants on gastrointestinal health.
    Keywords:  Ambient PM; Autophagic flux; Gut dysbiosis; Microbiome; Proliferation
    DOI:  https://doi.org/10.1016/j.ecoenv.2024.117171
  75. Curr Pharm Des. 2024 Oct 16.
    Uric Acid: A Biomarker and Pathogenic Factor of Affective Disorders and Neurodegenerative Diseases.
    Teng Chu, Ge Liu, Jing Liu, Yue Wu, Weirong Fang.
      Uric acid (UA), the end-product of purine metabolism, has a complicated physiological role in the body, showing the combination of regulating inflammatory response, promoting oxidation/anti-oxidation, and modifying autophagy activity in vivo. Meanwhile, various research and theories support that inflammation, oxidative stress, and other risk factors promote the onset and progression of affective disorders and neurodegenerative diseases. Existing studies suggest that UA may be involved in the pathophysiological processes of affective disorders in various ways, and there has been a gradual advance in the understanding of the interplay between UA levels and affective disorders and neurodegenerative diseases. This review summarized the role of UA in the process of inflammation, oxidative stress, and autophagy. On this basis, we discussed the correlation between UA and affective disorders and several neurodegenerative diseases, and simultaneously analyzed the possible mechanism of its influence on affective disorders and neurodegenerative diseases, to provide a theoretical basis for UA as a biomarker or therapeutic target for the diagnosis of these diseases.
    Keywords:  Uric acid; affective disorders; autophagy; inflammation; neurodegenerative diseases; oxidative stress
    DOI:  https://doi.org/10.2174/0113816128333916241003180018
  76. Cells. 2024 Oct 08. pii: 1664. [Epub ahead of print]13(19):
    Oncological Aspects of Lysosomal Storage Diseases.
    Agnieszka Ługowska.
      Lysosomal storage diseases (LSDs) are caused by the deficient activity of a lysosomal hydrolase or the lack of a functional membrane protein, transporter, activator, or other protein. Lysosomal enzymes break down macromolecular compounds, which contribute to metabolic homeostasis. Stored, undegraded materials have multiple effects on cells that lead to the activation of autophagy and apoptosis, including the toxic effects of lyso-lipids, the disruption of intracellular Ca2+ ion homeostasis, the secondary storage of macromolecular compounds, the activation of signal transduction, apoptosis, inflammatory processes, deficiencies of intermediate compounds, and many other pathways. Clinical observations have shown that carriers of potentially pathogenic variants in LSD-associated genes and patients affected with some LSDs are at a higher risk of cancer, although the results of studies on the frequency of oncological diseases in LSD patients are controversial. Cancer is found in individuals affected with Gaucher disease, Fabry disease, Niemann-Pick type A and B diseases, alfa-mannosidosis, and sialidosis. Increased cancer prevalence has also been reported in carriers of a potentially pathogenic variant of an LSD gene, namely CLN3, SGSH, GUSB, NEU1, and, to a lesser extent, in other genes. In this review, LSDs in which oncological events can be observed are described.
    Keywords:  cancer; lysosomal hydrolases; lysosomal storage diseases
    DOI:  https://doi.org/10.3390/cells13191664
  77. Mol Cell. 2024 Oct 17. pii: S1097-2765(24)00777-9. [Epub ahead of print]84(20): 3868-3870
    Crossing the border: Replication fork adducts move to lysosomes for autophagic repair.
    Sangin Kim, Roger A Greenberg.
      In a recent study in Cell, Lascaux et al.1 implicate TEX264 in the autophagy-driven resolution of nuclear topoisomerase 1 cleavage complexes (TOP1cc) in lysosomes, altering current concepts on the mechanism of action for clinically relevant doses of TOP1 inhibitors.
    DOI:  https://doi.org/10.1016/j.molcel.2024.09.021
  78. Biomed Pharmacother. 2024 Oct 16. pii: S0753-3322(24)01436-7. [Epub ahead of print]180 117550
    Modulating autophagy to boost the antitumor efficacy of TROP2-directed antibody-drug conjugate in pancreatic cancer.
    Caili Xu, Xiting Huang, Qinchao Hu, Wenjing Xue, Kaicheng Zhou, Xingxiu Li, Yanyang Nan, Dianwen Ju, Ziyu Wang, Xuyao Zhang.
      Pancreatic cancer, characterized by a dismal prognosis and limited treatment options, persists as a formidable challenge in oncology. Trophoblast cell surface antigen 2 (TROP2)-directed antibody-drug conjugates have achieved great success in solid tumors such as breast cancer and uroepithelial carcinoma. However, their efficacy against pancreatic cancer was insufficient in clinical trials, necessitating an imperative exploration of underlying mechanisms and new therapeutic strategies. In this study, we indicated that αTROP2-MMAE, an antibody-drug conjugate targeting TROP2, induced apoptosis through the caspase-9/PARP pathway and exerted potent antitumor effects against TROP2-positive pancreatic cancer. Simultaneously, RNA sequencing suggested significant changes in autophagy after αTROP2-MMAE treatment. The formation of autophagosomes and activation of autophagic flux were markedly induced through mechanisms associated with suppressing the activation of the Akt/mTOR pathway. The addition of pharmacological inhibitors of autophagy enhanced the cytotoxicity and apoptosis caused by αTROP2-MMAE, revealing the cytoprotective role of autophagy in TROP2-positive pancreatic cancer. In the subcutaneous xenograft model using BxPC3 cells, the combined administration of αTROP2-MMAE and an autophagy inhibitor elevated the tumor inhibition rate of αTROP2-MMAE from 71.6 % to 99.0 %, resulting in the eradication of tumors in half of the mice. Collectively, our research demonstrated for the first time the cytoprotective role of autophagy in TROP2-targeted antibody-drug conjugate therapy for pancreatic cancer, providing new perspectives for mechanistic exploration and therapeutic strategies in the treatment of pancreatic cancer.
    Keywords:  Antibody-drug conjugate; Apoptosis; Autophagy; Pancreatic cancer; TROP2
    DOI:  https://doi.org/10.1016/j.biopha.2024.117550
  79. Sci Rep. 2024 10 14. 14(1): 24008
    Treatment of polyethylene microplastics degraded by ultraviolet light irradiation causes lysosome-deregulated cell death.
    Sota Manabe, Yuya Haga, Hirofumi Tsujino, Yudai Ikuno, Haruyasu Asahara, Kazuma Higashisaka, Yasuo Tsutsumi.
       BACKGROUND: Microplastics (MPs), plastic particles < 5 mm in size, are prevalent in the environment, and human exposure to them is inevitable. To assess the potential risk of MPs on human health, it is essential to consider the physicochemical properties of environmental MPs, including polymer types, size, shape, and surface chemical modifications. Notably, environmental MPs undergo degradation due to external factors such as ultraviolet (UV) rays and waves, leading to changes in their surface characteristics. However, limited knowledge exists regarding the health effects of MPs, with a specific focus on their surface degradation. This study concentrates on cytotoxic MPs with surface degradation through UV irradiation, aiming to identify the mechanisms underlying their cell toxicity.
    RESULTS: Polyethylene (PE) and surface-degraded PE achieved through UV light irradiation were employed as model MPs in this study. We explored the impact of PE and degraded PE on cell death in murine macrophage cell line RAW264.7 cells and human monocyte cell line THP-1 cells. Flow cytometric analysis revealed that degraded PE induced programmed cell death without activating caspase 3, while non-degraded PE did not trigger programmed cell death. These findings suggest that degraded PE might induce programmed cell death through mechanisms other than caspase-driven apoptosis. To understand the mechanisms of cell death, we investigated how cells responded to degraded PE-induced cellular stress. Immunofluorescence and western blotting analyses demonstrated that degraded PE induced autophagosome formation and increased p62 expression, indicating inhibited autophagy flux after exposure to degraded PE. Furthermore, degraded PE exposure led to a decrease in acidic lysosomes, indicating lysosomal dysregulation. These results imply that degraded PE induces lysosomal dysfunction, subsequently causing autophagy dysregulation and cell death.
    CONCLUSIONS: This study unveils that UV-induced degradation of PE results in cell death attributed to lysosomal dysfunction. The findings presented herein provide novel insights into the effects of surface-degraded MPs on biological responses.
    Keywords:  Autophagy; Lysosome dysregulation; Microplastics; Polyethylene microplastics; Surface degradation of microplastics
    DOI:  https://doi.org/10.1038/s41598-024-74800-y
  80. Autophagy Rep. 2024 ;pii: 2402675. [Epub ahead of print]3(1):
    Et tu, Brute? TFEB promotes virus replication before being cleaved by a viral protease.
    Alagie Jassey, William T Jackson.
      
    Keywords:  NEAR; TFEB; autophagy; nonlytic release; virus
    DOI:  https://doi.org/10.1080/27694127.2024.2402675
  81. Aesthetic Plast Surg. 2024 Oct 14.
    PTB Regulates Keloid Fibroblast Migration and Proliferation Through Autophagy.
    Rong Huang, Bing Han, Jianzhong Peng, Hu Jiao.
       BACKGROUND: Keloid disease is a chronic fibroproliferative disease that occurs after tissue injury, and the currently available treatments are unsatisfactory.
    OBJECTIVES: We aimed to explore the level of autophagy in keloid fibroblasts (KFbs) and adjacent normal fibroblasts (NFbs). In addition, whether polypyrimidine tract-binding protein (PTB) regulates the biological functions of KFbs via autophagy was also investigated.
    METHODS: The morphology of fibroblasts in normal skin and keloids was observed transmission electron microscopy. We silenced PTB with PTB-specific siRNA to determine whether PTB-regulated KFb proliferation. Acridine orange and LysoTracker Red staining was performed to label acidic compartments. Interestingly, when autophagy was inhibited by wortmannin, the PTB knockdown-mediated decrease in KFb migration and proliferation was abolished, while the collagen I and III levels were not altered; these results indicated that PTB regulated the migration and proliferation of KFbs via autophagy, while collagen synthesis occurred independently of PTB regulation.
    RESULTS: Many activities related to the survival and function of KFbs are controlled by PTB. Transmission electron microscopy revealed more autophagosomes and autolysosomes in KFbs than in NFbs. PTB induced autophagy in KFbs, as demonstrated by the significantly greater number of autophagosomes in KFbs after PTB knockdown, which was revealed by acridine orange and LysoTracker staining.
    CONCLUSIONS: Our study is the first to show that PTB regulates the migration and proliferation of KFbs via autophagy and that PTB regulates collagen synthesis in KFbs in an autophagy-independent manner.
    NO LEVEL ASSIGNED: This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .
    Keywords:  Autophagy; Fibroblast; Keloid; Polypyrimidine tract‐binding protein
    DOI:  https://doi.org/10.1007/s00266-024-04375-6
  82. Biomed Pharmacother. 2024 Oct 17. pii: S0753-3322(24)01452-5. [Epub ahead of print]180 117566
    Bidirectional modulation of extracellular vesicle-autophagy axis in acute lung injury: Molecular mechanisms and therapeutic implications.
    Linqiang Tian, Jie Jin, Qianying Lu, Huajing Zhang, Sijia Tian, Feng Lai, Chuanchuan Liu, Yangfan Liang, Yujia Lu, Yanmei Zhao, Sanqiao Yao, Wenjie Ren.
      Acute lung injury (ALI), a multifactorial pathological condition, manifests through heightened inflammatory responses, compromised lung epithelial-endothelial barrier function, and oxidative stress, potentially culminating in respiratory failure and mortality. This study explores the intricate interplay between two crucial cellular mechanisms-extracellular vesicles (EVs) and autophagy-in the context of ALI pathogenesis and potential therapeutic interventions.EVs, bioactive membrane-bound structures secreted by cells, serve as versatile carriers of molecular cargo, facilitating intercellular communication and significantly influencing disease progression. Concurrently, autophagy, an essential intracellular degradation process, maintains cellular homeostasis and has emerged as a promising therapeutic target in ALI and acute respiratory distress syndrome.Our research unveils a fascinating "EV-Autophagy dual-drive pathway," characterized by reciprocal regulation between these two processes. EVs modulate autophagy activation and inhibition, while autophagy influences EV production, creating a dynamic feedback loop. This study posits that precise manipulation of this pathway could revolutionize ALI treatment strategies.By elucidating the mechanisms underlying this cellular crosstalk, we open new avenues for targeted therapies. The potential for engineered EVs to fine-tune autophagy in ALI treatment is explored, alongside innovative concepts such as EV-based vaccines for ALI prevention and management. This research not only deepens our understanding of ALI pathophysiology but also paves the way for novel, more effective therapeutic approaches in critical care medicine.
    Keywords:  acute lung injury; autophagy; extracellular vesicles; inflammation; oxidative stress; vaccine
    DOI:  https://doi.org/10.1016/j.biopha.2024.117566
  83. eNeuro. 2024 Oct 15. pii: ENEURO.0269-24.2024. [Epub ahead of print]
    Tetrahydroxy stilbene glucoside promotes mitophagy and ameliorates neuronal injury after cerebral ischemia reperfusion via promoting USP10 mediated YBX1 stability.
    Yuxian Li, Ke Hu, Jie Li, Xirong Yang, Xiuyu Wu, Qian Liu, Yuefu Chen, Yan Ding, Lingli Liu, Qiansheng Yang, Guangwei Wang.
      Tetrahydroxy stilbene glucoside (TSG) from polygonum multiflorum exerts neuroprotective effects after ischemic stroke. We explored whether TSG improved ischemic stroke injury via PINK1/Parkin-mediated mitophagy. Oxygen glucose deprivation/reoxygenation (OGD/R) in vitro model and middle cerebral artery occlusion (MCAO) rat model were established. Cerebral injury was assessed by neurological score, hematoxylin and eosin staining, TTC staining and brain water content. Apoptosis, cell viability and mitochondrial membrane potential were assessed by flow cytometry, CCK-8 and JC-1 staining, respectively. Co-localization of LC3-labeled autophagosomes with LAMP2-labeled lysosomes or Tomm20-labeled mitochondria was observed with fluorescence microscopy. Ubiquitination level was determined using ubiquitination assay. The interaction between molecules was validated by co-immunoprecipitation and GST pull-down. We found that TSG promoted mitophagy and improved cerebral I/R damage in MCAO rats. In OGD/R-subjected neurons, TSG promoted mitophagy, repressed neuronal apoptosis, upregulated Y-box binding protein-1 (YBX1) and activated PINK1/Parkin signaling. TSG upregulated ubiquitin-specific peptidase 10 (USP10) to elevate YBX1 protein. Furthermore, USP10 inhibited ubiquitination-dependent YBX1 degradation. USP10 overexpression activated PINK1/Parkin signaling and promoted mitophagy, which were reversed by YBX1 knockdown. Moreover, TSG upregulated USP10 to promote mitophagy and inhibited neuronal apoptosis. Collectively, TSG facilitated PINK1/Parkin pathway mediated mitophagy by upregulating USP10/YBX1 axis to ameliorate ischemic stroke.Significance Statement: Ischemic stroke is one of leading causes of disability and death worldwide. Previous studies have demonstrated a neuroprotective role of TSG in ischemic stroke, while the underlying mechanism is still not fully understood. Here, this study confirmed that TSG relieved cerebral I/R injury in vivo and in vitro via facilitated PINK1/Parkin-mediated mitophagy. In addition, we further identified the molecular mechanism by which TSG regulates mitochondrial autophagy. Our study provided new insights into the protective role TSG in ischemic stroke via regulating mitophagy.
    DOI:  https://doi.org/10.1523/ENEURO.0269-24.2024
  84. Cell Signal. 2024 Oct 11. pii: S0898-6568(24)00442-X. [Epub ahead of print]124 111469
    Txnip promotes autophagic apoptosis in diabetic cardiomyopathy by upregulating FoxO1 and its acetylation.
    Yaoting Zhang, Bing Li, Yu Fu, He Cai, Yang Zheng.
      Autophagy dysfunction and apoptosis exacerbate the risk of heart failure in patients with diabetic cardiomyopathy (DCM). However, the interactions between autophagy and apoptosis in DCM and their underlying mechanisms remain poorly understood. This study induced type 1 DCM in C57BL/6 mice via streptozotocin injection and exposed H9C2 cells to high glucose to investigate these mechanisms. The study revealed a significant elevation in autophagic vesicles and compromised autophagic flux, accompanied by pronounced myocardial cell apoptosis in the myocardium of diabetic mice. Long-term exposure to high glucose in H9C2 cells led to enhanced autophagosome formation and impaired autophagic flux, while inhibition of autophagy with 3-MA reduced cell apoptosis. Additionally, we observed an increase in Txnip expression in the myocardium of diabetic mice and in high glucose-treated H9C2 cells, which regulates autophagic apoptosis in high glucose-treated H9C2 cells. Furthermore, Txnip regulates autophagic apoptosis through the modulation of forkhead box-1 (FoxO1) expression and acetylation. Prolonged high glucose exposure resulted in increased levels of phosphorylated sirtuin 1 (SIRT1) and reduced SIRT1/FoxO1 interaction, changes that were ameliorated by Txnip knockdown. Txnip overexpression elevated FoxO1 levels, which could be suppressed by NAC and GSH. These findings revealed that Txnip mediates autophagic apoptosis in DCM by upregulating FoxO1 via ROS and enhancing FoxO1 acetylation through the suppression of SIRT1 activity. The discovery of this new mechanism provides new perspectives and potential therapeutic targets for understanding and treating DCM.
    Keywords:  Acetylation; Apoptosis; Autophagy; FoxO1; Txnip
    DOI:  https://doi.org/10.1016/j.cellsig.2024.111469
  85. Ageing Res Rev. 2024 Oct 16. pii: S1568-1637(24)00363-5. [Epub ahead of print] 102545
    The Role of Sirtuin 1 in Ageing and Neurodegenerative Disease: A Molecular Perspective.
    Riya Thapa, Ehssan Moglad, Muhammad Afzal, Gaurav Kumar, Asif Ahmad Bhat, Waleed Hassan Almalki, Imran Kazmi, Sami I Alzarea, Kumud Pant, Thakur Gurjeet Singh, Sachin Kumar Singh, Haider Ali.
      Sirtuin 1 (SIRT1), an NAD+-dependent deacetylase, has emerged as a key regulator of cellular processes linked to ageing and neurodegeneration. SIRT1 modulates various signalling pathways, including those involved in autophagy, oxidative stress, and mitochondrial function, which are critical in the pathogenesis of neurodegenerative diseases. This review explores the therapeutic potential of SIRT1 in several neurodegenerative disorders, including Alzheimer's disease (AD), Parkinson's disease (PD), Huntington's disease (HD), and Amyotrophic Lateral Sclerosis (ALS). Preclinical studies have demonstrated that SIRT1 activators, such as resveratrol, SRT1720, and SRT2104, can alleviate disease symptoms by reducing oxidative stress, enhancing autophagic flux, and promoting neuronal survival. Ongoing clinical trials are evaluating the efficacy of these SIRT1 activators, providing hope for future therapeutic strategies targeting SIRT1 in neurodegenerative diseases. This review explores the role of SIRT1 in ageing and neurodegenerative diseases, with a particular focus on its molecular mechanisms, therapeutic potential, and clinical applications.
    Keywords:  Alzheimer's Disease; Cellular Homeostasis; Huntington's Disease; Neurodegenerative Diseases; Parkinson's Disease; Sirtuin 1
    DOI:  https://doi.org/10.1016/j.arr.2024.102545
  86. Int J Biol Macromol. 2024 Oct 12. pii: S0141-8130(24)07329-X. [Epub ahead of print] 136520
    "β-glucan signalling stimulates NOX-2 dependent autophagy and LC-3 associated autophagy (LAP) pathway".
    Firoz Ahmad, Shad Ahmad, Anurag Kumar Srivastav, Tarun Kumar Upadhyay, Adil Husain, Mohd Khubaib, Sojin Kang, Moon Nyeo Park, Bonglee Kim, Rolee Sharma.
      β-Glucans, a complex polysaccharide derived from fungal and yeast cell walls, play a crucial role in modulating immune responses through their interaction with receptors such as Dectin-1 and Complement receptor 3 (CR-3). This review provides an in-depth analysis of the molecular mechanisms by which β-glucans activate receptor-mediated signalling pathways, focusing particularly on the LC3-associated phagocytosis (LAP) and autophagy pathways. Hence, we explore how β-glucan receptor engagement stimulates NADPH oxidase 2 (NOX-2), leading to the intracellular production of significant level of reactive oxygen species (ROS) essential for both conventional autophagy and LAP. While significant progress has been made, but the regulation of phago-lysosomal maturation and antigen presentation during LAP induction still remains less explored. This review main aims were to provide a comprehensive overview of these pathways and their regulation by β-glucans. By consolidating current knowledge, we seek to highlight how these mechanisms can be leveraged for therapeutic applications, particularly in the context of tuberculosis (TB) management, where β-glucans could serve as host-directed adjuvant therapies to combat drug-resistant strains. Despite major advancements in this field, currently key research gaps still persist, including detailed molecular interactions between β-glucan receptors and NOX-2 and the translation of these findings to in vivo models and clinical investigations. This review underscores the need for further research to explore the therapeutic potential of β-glucans in managing not only tuberculosis but also other diseases such as cancer, cardiovascular conditions, and metabolic disorders.
    Keywords:  Autophagy; Dectin-1; NOX-2; PAMPs; Toll like receptors; β-Glucan
    DOI:  https://doi.org/10.1016/j.ijbiomac.2024.136520
  87. J Hazard Mater. 2024 Oct 15. pii: S0304-3894(24)02760-2. [Epub ahead of print]480 136181
    MC-LR disrupts dopamine synthesis in the substantia nigra of midbrain by enhancing the chaperone-mediated autophagy pathway through direct binding to ERK2.
    Huifang Wu, Minghao Yan, Tong Wu, Xiaodong Han.
      Microcystins are environmental toxins produced by freshwater cyanobacteria. Microcystin-LR (MC-LR) is one of the most abundant and harmful isomers. MC-LR poses a serious threat to human health. MC-LR could penetrate the blood-brain barrier of mice and accumulate in the substantia nigra (SN) of the midbrain, leading to a reduction in dopamine levels and Parkinson's disease (PD)-like motor dysfunction in mice. The reduction in dopamine levels is a key factor contributing to movement disorders in humans with PD. Dopamine is synthesized in the dopaminergic neurons of the SN by the actions of tyrosine hydroxylase (TH) and dihydroxyphenylalanine decarboxylase (DDC). In this study, we found that MC-LR could enter dopaminergic neurons in the SN and directly bound to extracellular signal-regulated kinase 2 (ERK2), enhancing ERK2 stability. ERK2 further enhanced the transcriptional activity of Heat Shock Protein Family A Member 8 (HSPA8) and promoted the expression of Heat shock cognate 71 kDa protein (HSC70), which in turn amplified the chaperone-mediated autophagy (CMA) pathway and accelerated the degradation of TH and DDC. This affected the dopamine synthesis process, resulting in a significant reduction in dopamine levels. The study is the first to reveal that ERK2 was a direct target of MC-LR, and further enhanced CMA affecting dopamine synthesis, which has important theoretical and practical significance for environmental safety management.
    Keywords:  Chaperone-mediated autophagy; Dopamine; Extracellular signal-regulated kinase 2; Microcystin-LR; Neurotoxicity
    DOI:  https://doi.org/10.1016/j.jhazmat.2024.136181
  88. J Vis Exp. 2024 Sep 27.
    Dual-color Correlative Light and Electron Microscopy for the Visualization of Interactions between Mitochondria and Lysosomes.
    Minkyo Jung, Ji Young Mun.
      Cellular organelles, such as mitochondria and lysosomes, display dynamic structures. Despite the higher resolution of transmission electron microscopy for structural analysis, light microscopy is essential for the visualization of dynamic organelles by target-specific labeling. The following protocol describes a method that combines dual-color correlative light and electron microscopy (CLEM) to observe the interactions between mitochondria and lysosomes. In this study, mitochondria were labeled with mEosEM (Mito-mEosEM) and lysosomes with TMEM192-V5-APEX2. The results obtained from CLEM images enable us to observe the changes in the interactions between mitochondria and lysosomes under external stress conditions. Treatment with bafilomycin (BFA), which inhibits lysosomal function, resulted in an increase in contact between mitochondria and lysosomes, leading to the formation of fragmented mitochondria trapped inside lysosomes. Conversely, treatment with U18666A, which inhibits cholesterol export from lysosomes, caused lysosomes to be surrounded by mitochondria, indicating a distinct form of interaction. This study presents an effective method for observing the interactions between mitochondria and lysosomes in fixed cells. Furthermore, CLEM imaging with dual-color probes offers a powerful tool for future investigations of organelle dynamics and their implications for cell function and pathology.
    DOI:  https://doi.org/10.3791/67020
  89. Neurobiol Dis. 2024 Oct 13. pii: S0969-9961(24)00301-2. [Epub ahead of print]202 106701
    Neuropathology in an α-synuclein preformed fibril mouse model occurs independent of the Parkinson's disease-linked lysosomal ATP13A2 protein.
    Caio M Massari, Dylan J Dues, Alexis Bergsma, Kayla Sipple, Maxwell Frye, Erin T Williams, Darren J Moore.
      Loss-of-function mutations in the ATP13A2 (PARK9) gene are implicated in early-onset autosomal recessive Parkinson's disease (PD) and other neurodegenerative disorders. ATP13A2 encodes a lysosomal transmembrane P5B-type ATPase that is highly expressed in brain and specifically within the substantia nigra pars compacta (SNc). Recent studies have revealed its normal role as a lysosomal polyamine transporter, although its contribution to PD-related pathology remains unclear. Cellular studies report that ATP13A2 can regulate α-synuclein (α-syn) secretion via exosomes. However, the relationship between ATP13A2 and α-syn in animal models remains inconclusive. ATP13A2 knockout (KO) mice exhibit lysosomal abnormalities and reactive astrogliosis but do not develop PD-related neuropathology. Studies manipulating α-syn levels in mice lacking ATP13A2 indicate minimal effects on pathology. The delivery of α-syn preformed fibrils (PFFs) into the mouse striatum is a well-defined model to study the development and spread of α-syn pathology. In this study we unilaterally injected wild-type (WT) and homozygous ATP13A2 KO mice with mouse α-syn PFFs in the striatum and evaluated mice for neuropathology after 6 months. The distribution, spread and extent of α-syn aggregation in multiple regions of the mouse brain was largely independent of ATP13A2 expression. The loss of nigrostriatal pathway dopaminergic neurons and their nerve terminals induced by PFFs were equivalent in WT and ATP13A2 KO mice. Reactive astrogliosis was induced equivalently by α-syn PFFs in WT and KO mice but was already significantly higher in ATP13A2 KO mice due to pre-existing reactive gliosis. We did not identify asymmetric motor disturbances, microglial activation, or axonal damage induced by α-syn PFFs in WT or KO mice. Although α-syn PFFs induce an increase in lysosomal number in the SNc in general, TH-positive dopaminergic neurons did not exhibit either increased lysosomal area or intensity, regardless of genotype. Our study evaluating the spread of α-syn pathology reveals no exacerbation of α-syn pathology, neuronal loss, astrogliosis or motor deficits in ATP13A2 KO mice, suggesting that selective lysosomal abnormalities resulting from ATP13A2 loss do not play a major role in α-syn clearance or propagation in vivo.
    Keywords:  ATP13A2; Alpha-synuclein; Lysosome; Neurodegeneration; Parkinson's disease
    DOI:  https://doi.org/10.1016/j.nbd.2024.106701
  90. Free Radic Biol Med. 2024 Oct 11. pii: S0891-5849(24)00981-X. [Epub ahead of print]225 398-414
    Melatonin ameliorates chronic sleep deprivation against memory encoding vulnerability: Involvement of synapse regulation via the mitochondrial-dependent redox homeostasis-induced autophagy inhibition.
    Wei Wang, Zixu Wang, Jing Cao, Yulan Dong, Yaoxing Chen.
      Voluntary sleep curtailment is increasingly more rampant in modern society and compromises healthy cognition, including memory, to varying degrees. However, whether memory encoding is impaired after chronic sleep deprivation (CSD) and the underlying molecular mechanisms involved remain unclear. Here, using the mice, we tested the impact of CSD on the encoding abilities of social recognition-dependent memory and object recognition-dependent memory. We found that memory encoding was indeed vulnerable to CSD, while memory retrieval remained unaffected. The hippocampal neurons of mice with memory encoding deficits exhibited significant synapse damage and hyperactive autophagy, which dissipates during regular sleep cycles. This excessive autophagy appeared to be triggered by damage to mitochondrial DNA (mtDNA), resulting from oxidative stress within the mitochondria. The relief at the behavioral and molecular biological levels can be achieved with intraperitoneal injections of the antioxidant compound melatonin. Moreover, our in vitro experiments using HT-22 cells demonstrated that oxidative stress induced by hydrogen peroxide led to oxidative damage, including mtDNA damage, and activation of autophagy. Melatonin treatment effectively countered these effects, restoring redox homeostasis and reducing excessive autophagic activity. Notably, this protective effect was not observed when melatonin was administered as a pre-treatment. Together, our findings reveal the vulnerability of memory encoding during chronic sleep curtailment, which is caused by oxidative stress and consequent enhancement of autophagy, suggest a potential therapeutic strategy for addressing these effects following prolonged wakefulness through melatonin intervention, and reiterate the significance of adequate sleep for memory formation and retention.
    Keywords:  Autophagy; Chronic sleep deprivation; Hippocampal synapse; Melatonin; Memory encoding; Oxidative stress
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2024.10.279
  91. Front Physiol. 2024 ;15 1493710
    Editorial: Autophagy: unveiling the mechanisms and implications in health and disease.
    Shibin Cheng, Xiaodi Chen, Aihua Liao.
      
    Keywords:  Alzheimer’s disease; autophagy; bile duct carcinoma; oxidative stress; rotator cuff injuries
    DOI:  https://doi.org/10.3389/fphys.2024.1493710
  92. Biomed Rep. 2024 Dec;21(6): 185
    miR‑1343‑3p inhibits autophagy by directly targeting ATG7 in multiple myeloma cells.
    Yanrong Guo, Xiaoxiao Ding, Changling Dai, Wenwen Wang, Jianlin Chen, Sai Chen, Linjun Yang, Guang Chen.
      Multiple myeloma (MM) is the second most common type of hematological malignancy globally. Despite application of several new drugs, such as daratumumab, bortezomib/lenalidomide/dexamethasone, in combination with hematopoietic stem cell transplantation, overall prognosis remains poor and the pathological mechanism of MM is still unknown. The present study used TargetScan to predict autophagy-related 7 (ATG7) as a candidate target gene of microRNA (miR)-1343-3p and confirmed the interaction between miR-1343-3p and the ATG7 3' untranslated region (3'UTR) using a dual-luciferase reporter assay. In U266 and RPMI-8226 MM cell lines, miR-1343-3p mimic transfection decreased mRNA and protein levels of ATG7, while miR-1343-3p inhibition increased ATG7 expression levels using reverse transcription-qPCR and western blot analysis. miR-1343-3p mimic transfection inhibited U266 and RPMI-8226 cell survival. Finally, miR-1343-3p regulated ATG7 and autophagy in MM cells using western blot analysis. The present findings suggested that miR-1343-3p may regulate ATG7 and autophagy by directly targeting the 3'UTR of ATG7. To the best of our knowledge, there are no direct data showing the roles of miR-1343-3p in development of MM; however, miR-1343-3p may be considered a potential target for MM treatment.
    Keywords:  autophagy; autophagy-related 7; microRNA-1343-3p; multiple myeloma
    DOI:  https://doi.org/10.3892/br.2024.1873
  93. Apoptosis. 2024 Oct 13.
    SHCBP1 promotes cisplatin resistance of ovarian cancer through AKT/mTOR/Autophagy pathway.
    Gonghua Qi, Hanlin Ma, Kai Teng, Panpan Gai, Yanmin Gong, Jingying Chen, Xia Luo, Beihua Kong.
      Ovarian cancer caused the highest cancer-related mortality among female reproductive system malignancies. Platinum-based chemotherapy is still the footstone of the chemotherapy for ovarian cancer. However, the molecular mechanisms underlying cisplatin insensitivity and resistance remain unclear. SHC SH2 domain-binding protein 1 (SHCBP1) plays critical roles in the progression and drug resistance of different types of cancer. However, the biological function of SHCBP1 in ovarian cancer progression and cisplatin resistance remains obscure. In this study, we found that SHCBP1 was upregulated in ovarian cancer and the upregulated SHCBP1 has growth-promoting effect on ovarian cancer cells. Furthermore, SHCBP1 silencing sensitize ovarian cancer cells to cisplatin (hereafter referred to as CDDP). Mechanism analysis revealed that SHCBP1 activated the Akt/mTOR pathway and further inhibited autophagy in ovarian cancer cells. Meanwhile, autophagy inhibitors combined with SHCBP1 knockdown enhances CDDP sensitivity. In addition, knockdown of SHCBP1 restricted the proliferation of tumors and increased the cisplatin sensitivity in vivo. These findings suggested that upregulated SHCBP1 promoted the proliferation and CDDP resistance of ovarian cancer. The combination of SHCBP1 inhibition and cisplatin treatment might lead to substantial progress in ovarian cancer targeted therapy.
    Keywords:  AKT/mTOR; Autophagy; Cisplatin sensitivity; Ovarian cancer; SHCBP1
    DOI:  https://doi.org/10.1007/s10495-024-02027-3
  94. Int J Mol Sci. 2024 Oct 03. pii: 10659. [Epub ahead of print]25(19):
    Trehalose Attenuates In Vitro Neurotoxicity of 6-Hydroxydopamine by Reducing Oxidative Stress and Activation of MAPK/AMPK Signaling Pathways.
    Danijela Stevanovic, Ljubica Vucicevic, Maja Misirkic-Marjanovic, Tamara Martinovic, Milos Mandic, Ljubica Harhaji-Trajkovic, Vladimir Trajkovic.
      The effects of trehalose, an autophagy-inducing disaccharide with neuroprotective properties, on the neurotoxicity of parkinsonian mimetics 6-hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpiridinium (MPP+) are poorly understood. In our study, trehalose suppressed 6-OHDA-induced caspase-3/PARP1 cleavage (detected by immunoblotting), apoptotic DNA fragmentation/phosphatidylserine externalization, oxidative stress, mitochondrial depolarization (flow cytometry), and mitochondrial damage (electron microscopy) in SH-SY5Y neuroblastoma cells. The protection was not mediated by autophagy, autophagic receptor p62, or antioxidant enzymes superoxide dismutase and catalase. Trehalose suppressed 6-OHDA-induced activation of c-Jun N-terminal kinase (JNK), p38 mitogen-activated protein kinase (MAPK), and AMP-activated protein kinase (AMPK), as revealed by immunoblotting. Pharmacological/genetic inhibition of JNK, p38 MAPK, or AMPK mimicked the trehalose-mediated cytoprotection. Trehalose did not affect the extracellular signal-regulated kinase (ERK) and mechanistic target of rapamycin complex 1 (mTORC1)/4EBP1 pathways, while it reduced the prosurvival mTORC2/AKT signaling. Finally, trehalose enhanced oxidative stress, mitochondrial damage, and apoptosis without decreasing JNK, p38 MAPK, AMPK, or AKT activation in SH-SY5Y cells exposed to MPP+. In conclusion, trehalose protects SH-SY5Y cells from 6-OHDA-induced oxidative stress, mitochondrial damage, and apoptosis through autophagy/p62-independent inhibition of JNK, p38 MAPK, and AMPK. The opposite effects of trehalose on the neurotoxicity of 6-OHDA and MPP+ suggest caution in its potential development as a neuroprotective agent.
    Keywords:  6-hydroxydopamine; AMP-activated protein kinase; JNK; MPP+; Parkinson’s disease; mitochondrial damage; oxidative stress; p38 MAPK; trehalose
    DOI:  https://doi.org/10.3390/ijms251910659
  95. Pharmacology. 2024 Oct 16. 1-22
    UCF101 Rescues against Diabetes-Evoked Cardiac Remodeling and Contractile Anomalies through AMPK-Mediated Induction of Mitophagy.
    Zhiqiang Zhuang, Yuxi Zhu, Jun Tao, Yandong Liu, Jie Lin, Chunjie Yang, Chule Dong, Xing Qin, Qun Li, Russel J Reiter, Guizhen Wang, Zhaohui Pei, Jun Ren.
       BACKGROUND: Diabetes mellitus is known to provoke devastating anomalies in myocardial structure and function while effective therapeutic regimen is still lacking. The selective protease inhibitor UCF101 (5-[5-(2-nitrophenyl) furfuryliodine]-1,3-diphenyl-2-thiobarbituric acid) has been shown to fend off ischemic heart injury although its impact on diabetic cardiomyopathy remains elusive.
    METHOD: Our present work was conducted to examine the effect of UCF101 on experimental diabetes-evoked cardiac geometric and functional abnormalities as well as mechanism involved. Adult mice were made diabetic using streptozotocin (STZ) while receiving UCF101 (7.15 mg/kg, i.p.) for 6 consecutive days.
    RESULT: STZ evidently evoked cardiac hypertrophy, interstitial fibrosis, mitochondrial ultrastructural damage, oxidative stress, dampened autophagy (LC3B, Beclin1, elevated p62), mitophagy (FUNDC1 and Parkin with elevated TOM20), increased left ventricular (LV) end systolic diameter, dampened fractional shortening, ejection fraction, cardiomyocyte shortening capacity, velocities of shortening/relengthening, and rise in intracellular Ca2+ in conjunction with elongated diastole and intracellular Ca2+ removal, the responses were overtly reconciled by UCF101 with little effect from UCF101 itself. Levels of cell injury markers Omi/HtrA2, TNFα, and stress signaling (JNK, ERK, p38) were overtly enhanced along with compromised phosphorylation of cellular fuel AMPK (Thr172) and cell survival molecule GSK3β, as well as downregulated SERCA2a and elevated phospholamban, the effect was reversed by UCF101 (except for SERCA2a). AMPK knockout, pharmacological inhibition, mitophagy inhibitor liensinine and parkin knockout nullified UCF101-offered cardioprotection in diabetes. UCF101 reversed STZ-induced upregulation in the AMPK degrading enzymes PP2A and PP2C.
    CONCLUSION: These findings denote that UCF101 rescues diabetes-instigated alterations in cardiac structure and contraction, likely through AMPK-mediated regulation of mitophagy.
    DOI:  https://doi.org/10.1159/000541569
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