bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2024–02–25
89 papers selected by
Viktor Korolchuk, Newcastle University
  1. mTORC1 activity oscillates throughout the cell cycle promoting mitotic entry and differentially influencing autophagy induction.
  2. Autophagy related genes mediated mitophagy in yeast, mammals and higher plants.
  3. TFEB activation triggers pexophagy for functional adaptation during oxidative stress under calcium deficient-conditions.
  4. Lysosomal storage, impaired autophagy and innate immunity in Gaucher and Parkinson's diseases: insights for drug discovery.
  5. HCV-induced autophagy and innate immunity.
  6. Autophagy: a necessary evil in cancer and inflammation.
  7. THSD1 Suppresses Autophagy-Mediated Focal Adhesion Turnover by Modulating the FAK-Beclin 1 Pathway.
  8. Advanced oxidation protein products attenuate the autophagy-lysosome pathway in ovarian granulosa cells by modulating the ROS-dependent mTOR-TFEB pathway.
  9. A SPLICS reporter reveals [Formula: see text]-synuclein regulation of lysosome-mitochondria contacts which affects TFEB nuclear translocation.
  10. VPS35 and retromer dysfunction in Parkinson's disease.
  11. SUMO Modifies GβL and Mediates mTOR Signaling.
  12. Mitochondrial Dysfunction and Protein Homeostasis in Aging: Insights from a Premature-Aging Mouse Model.
  13. The Role of Chaperone-Mediated Autophagy in Tissue Homeostasis and Disease Pathogenesis.
  14. GATOR1 Mutations Impair PI3 Kinase-Dependent Growth Factor Signaling Regulation of mTORC1.
  15. Going through changes - the role of autophagy during reprogramming and differentiation.
  16. Selective degradation of ribosomes during oncogene-induced senescence: molecular insights and biological perspectives.
  17. When autophagy meets placenta development and pregnancy complications.
  18. YAP knockdown repressed autophagy in fibroblasts to accelerate wound healing through regulating En1/mTOR axis.
  19. Autophagy Genes and Otitis Media Outcomes.
  20. New insights into GATOR2-dependent interactions and its conformational changes in amino acid sensing.
  21. UDP-glucose dehydrogenase supports autophagy-deficient PDAC growth via increasing hyaluronic acid biosynthesis.
  22. The Role of Autophagy in Human Uveal Melanoma and the Development of Potential Disease Biomarkers and Novel Therapeutic Paradigms.
  23. Contribution of Autophagy to Epithelial Mesenchymal Transition Induction during Cancer Progression.
  24. Targeting autophagy by antipsychotic phenothiazines: potential drug repurposing for cancer therapy.
  25. Autophagy-driven regulation of cisplatin response in human cancers: Exploring molecular and cell death dynamics.
  26. Dapagliflozin alleviates high glucose-induced injury of endothelial cells via inducing autophagy.
  27. Gonococcal OMV-delivered PorB induces epithelial cell mitophagy.
  28. Endothelial Mechanistic Target of Rapamycin Activation with Different Strains of R. rickettsii: Possible Role in Rickettsial Pathogenesis.
  29. The RNA-binding protein Msi2 regulates autophagy during myogenic differentiation.
  30. TRIM27 elicits protective immunity against tuberculosis by activating TFEB-mediated autophagy flux.
  31. Autophagy Determines Distinct Cell Fates in Human Amnion and Chorion Cells.
  32. ALLO-1- and IKKE-1-dependent positive feedback mechanism promotes the initiation of paternal mitochondrial autophagy.
  33. Mitophagy regulates mitochondrial number following pharmacological induction of mitochondrial biogenesis in renal proximal tubule cells.
  34. Retromer-dependent lysosomal stress in Parkinson's disease.
  35. Exploring the therapeutic potential of Rab11: A comprehensive study on its effectiveness in alleviating rotenone-induced molecular pathogenesis of Parkinson's disease in SH-SY5Y cells and its synergistic application with L-DOPA in Drosophila models.
  36. Inspiring Tactics with the Improvement of Mitophagy and Redox Balance for the Development of Innovative Treatment against Polycystic Kidney Disease.
  37. Different Levels of Autophagy Activity in Mesenchymal Stem Cells Are Involved in the Progression of Idiopathic Pulmonary Fibrosis.
  38. Endo-lysosomal dysfunction and neuronal-glial crosstalk in Niemann-Pick type C disease.
  39. BECLIN1 is essential for intestinal homeostasis involving autophagy-independent mechanisms through its function in endocytic trafficking.
  40. Mitochondria, Autophagy and Inflammation: Interconnected in Aging.
  41. Mitochondrial Quantity and Quality in Age-Related Sarcopenia.
  42. Sirtuins Affect Cancer Stem Cells via Epigenetic Regulation of Autophagy.
  43. Empagliflozin ameliorates the impaired osteogenic differentiation ability of adipose-derived stem cells in diabetic osteoporosis by activating autophagy.
  44. Disrupting circadian control of autophagy induces podocyte injury and proteinuria.
  45. The significance of targeting lysosomes in cancer immunotherapy.
  46. Arsenic disturbs neural tube closure involving AMPK/PKB-mTORC1-mediated autophagy in mice.
  47. Understanding the endo-lysosomal network in neurodegeneration.
  48. Role of autophagy in angiogenic potential of vascular pericytes.
  49. Drosophila TMEM63 and mouse TMEM63A are lysosomal mechanosensory ion channels.
  50. Differential effects of SORL1 deficiency on the endo-lysosomal network in human neurons and microglia.
  51. Membrane-Associated Ubiquitin Ligase RING Finger Protein 152 Orchestrates Melanogenesis via Tyrosinase Ubiquitination.
  52. Bortezomib modulated the autophagy-lysosomal pathway in a TFEB-dependent manner in multiple myeloma.
  53. Role of diacylglycerol O-acyltransferase 1 (DGAT1) in lipolysis and autophagy of adipose tissue from ketotic dairy cows.
  54. Mechanism and role of mitophagy in the development of severe infection.
  55. Immmunometabolism of systemic lupus erythematosus.
  56. Emodin activates autophagy to suppress oxidative stress and pyroptosis via mTOR-ULK1 signaling pathway and promotes multi-territory perforator flap survival.
  57. Inhibition of ULK1/2 and KRAS G12C controls tumor growth in preclinical models of lung cancer.
  58. Ginsenoside Rb1 alleviates 3-MCPD-induced renal cell pyroptosis by activating mitophagy.
  59. Dopamine enhances recovery after traumatic brain injury through ubiquitylation and autophagic degradation of RIPK1.
  60. Autophagy regulation and redox perturbation by transcrocetin suppress the growth of endometriosis.
  61. Role of autophagy in skin photoaging: A narrative review.
  62. Endo-lysosomal dysfunction in neurodegenerative diseases: opinion on current progress and future direction in the use of exosomes as biomarkers.
  63. Mouse oocytes sequester aggregated proteins in degradative super-organelles.
  64. The HIF-1α and mTOR Pathways Amplify Heterotopic Ossification.
  65. Targeting autophagy as a therapeutic strategy in pediatric acute lymphoblastic leukemia.
  66. The role of mitochondrial quality control mechanisms in chondrocyte senescence.
  67. Impairment of the glial phagolysosomal system drives prion-like propagation in a Drosophila model of Huntington's disease.
  68. Carnosic Acid against Lung Cancer: Induction of Autophagy and Activation of Sestrin-2/LKB1/AMPK Signalling.
  69. Thioredoxin-1 decreases alpha-synuclein induced by MPTP through promoting autophagy-lysosome pathway.
  70. The PINK1/Parkin pathway of mitophagy exerts a protective effect during prion disease.
  71. Lysosomal channels sensing forces.
  72. Pathogenesis of DJ-1/PARK7-Mediated Parkinson's Disease.
  73. Genome-wide screens identify SEL1L as an intracellular rheostat controlling collagen turnover.
  74. Mitochondrial quality control alterations and placenta-related disorders.
  75. SQSTM1/p62 is a prognostic molecular marker and potential therapeutic target for pancreatic neuroendocrine tumours.
  76. Mechanism and cellular function of direct membrane binding by the ESCRT and ERES-associated Ca2+-sensor ALG-2.
  77. Rapamycin inhibits B16 melanoma cell viability invitro and invivo by inducing autophagy and inhibiting the mTOR/p70‑S6k pathway.
  78. ATG5 attenuates inflammatory signaling in mouse embryonic stem cells to control differentiation.
  79. Stimulating VAPB-PTPIP51 ER-mitochondria tethering corrects FTD/ALS mutant TDP43 linked Ca2+ and synaptic defects.
  80. A metabolically controlled contact site between vacuoles and lipid droplets in yeast.
  81. Ferritinophagy: A novel insight into the double-edged sword in ferritinophagy-ferroptosis axis and human diseases.
  82. Activation of adenosine A2B receptor alleviates myocardial ischemia-reperfusion injury by inhibiting endoplasmic reticulum stress and restoring autophagy flux.
  83. Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Ameliorate Aging-Induced BTB Impairment in Porcine Testes by Activating Autophagy and Inhibiting ROS/NLRP3 Inflammasomes via the AMPK/mTOR Signaling Pathway.
  84. Enhanced Branched-Chain Amino Acid Metabolism Improves Age-Related Reproduction in C. elegans.
  85. ER remodeling via lipid metabolism.
  86. A mutational atlas for Parkin proteostasis.
  87. A free fatty acid receptor agonist inducing autophagy in HT-29 cells by downregulating the AKT/mTOR signaling pathway.
  88. Exposure of the inner mitochondrial membrane triggers apoptotic mitophagy.
  89. Targeted protein degradation via intramolecular bivalent glues.
  1. bioRxiv. 2024 Feb 07. pii: 2024.02.06.579216. [Epub ahead of print]
    mTORC1 activity oscillates throughout the cell cycle promoting mitotic entry and differentially influencing autophagy induction.
    Jay N Joshi, Ariel D Lerner, Frank Scallo, Alexandra N Grumet, Paul Matteson, James H Millonig, Alexander J Valvezan.
      Mechanistic Target of Rapamycin Complex 1 (mTORC1) is a master metabolic regulator that stimulates anabolic cell growth while suppressing catabolic processes such as autophagy. mTORC1 is active in most, if not all, proliferating eukaryotic cells. However, it remains unclear whether and how mTORC1 activity changes from one cell cycle phase to another. Here we tracked mTORC1 activity through the complete cell cycle and uncover oscillations in its activity. We find that mTORC1 activity peaks in S and G2, and is lowest in mitosis and G1. We further demonstrate that multiple mechanisms are involved in controlling this oscillation. The interphase oscillation is mediated through the TSC complex, an upstream negative regulator of mTORC1, but is independent of major known regulatory inputs to the TSC complex, including Akt, Mek/Erk, and CDK4/6 signaling. By contrast, suppression of mTORC1 activity in mitosis does not require the TSC complex, and instead involves CDK1-dependent control of the subcellular localization of mTORC1 itself. Functionally, we find that in addition to its well-established role in promoting progression through G1, mTORC1 also promotes progression through S and G2, and is important for satisfying the Wee1- and Chk1-dependent G2/M checkpoint to allow entry into mitosis. We also find that low mTORC1 activity in G1 sensitizes cells to autophagy induction in response to partial mTORC1 inhibition or reduced nutrient levels. Together these findings demonstrate that mTORC1 is differentially regulated throughout the cell cycle, with important phase-specific functional consequences in proliferating cells.
    DOI:  https://doi.org/10.1101/2024.02.06.579216
  2. Cell Mol Biol (Noisy-le-grand). 2024 Jan 31. 70(1): 1-11
    Autophagy related genes mediated mitophagy in yeast, mammals and higher plants.
    Muhammad Riaz, Razia Sultana, Javed Ahmad, Azhar Mehmood, Saira Sattar, Muhammad Hammad Tanveer, Muhammad Zulkiffal, Muhammad Sarwar.
      Autophagy is classified into macro-autophagy and micro-autophagy. Two major types of autophagy in the complex eukaryotic organism are microautophagy and macroautophagy. During microautophagy, cytoplasmic components that need to be degraded are taken up by lysosomes in animals and by vacuole in yeast and plants via the invagination of tonoplast. While macroautophagy is initiated after the formation of a cup-shaped membrane structure, a phagophore develops at cargo that grows in size and is sealed by double-membrane vesicles to form autophagosome; a generalized mechanism for degradation of the organelle. Autophagic removal of damaged mitochondria is a conserved cellular process to maintain a healthy mitochondrion called Mitophagy. In plants and animals, mitophagy has crucial roles in stress responses, senescence, development, and programmed cell death. Mitophagy appears in mammals, fungi, and plants but many genes that controlled mitophagy are absent from plants. Numerous studies have been conducted by using ATG mutants for the identification of functional roles of Autophagy Related Genes (ATG) required during the autophagy process at various steps like; auto phagosome formation, ATG protein recruitment, etc. The role of more than 25 ATG genes in mitophagy has been discussed in this review paper. The main parameters, reviewed and summarized in this review paper, are the name of species, common name, function, domain, deletion, induction, and localization of these autophagy-related genes in the cell. This review will facilitate the students, researchers, and academics for their further research insights.
    DOI:  https://doi.org/10.14715/cmb/2024.70.1.1
  3. Cell Commun Signal. 2024 Feb 21. 22(1): 142
    TFEB activation triggers pexophagy for functional adaptation during oxidative stress under calcium deficient-conditions.
    Laxman Manandhar, Raghbendra Kumar Dutta, Pradeep Devkota, Arun Chhetri, Xiaofan Wei, Channy Park, Hyug Moo Kwon, Raekil Park.
       BACKGROUND: Calcium is a ubiquitous intracellular messenger that regulates the expression of various genes involved in cell proliferation, differentiation, and motility. The involvement of calcium in diverse metabolic pathways has been suggested. However, the effect of calcium in peroxisomes, which are involved in fatty acid oxidation and scavenges the result reactive oxygen species (ROS), remains elusive. In addition, impaired peroxisomal ROS inhibit the mammalian target of rapamycin complex 1 (mTORC1) and promote autophagy. Under stress, autophagy serves as a protective mechanism to avoid cell death. In response to oxidative stress, lysosomal calcium mediates transcription factor EB (TFEB) activation. However, the impact of calcium on peroxisome function and the mechanisms governing cellular homeostasis to prevent diseases caused by calcium deficiency are currently unknown.
    METHODS: To investigate the significance of calcium in peroxisomes and their roles in preserving cellular homeostasis, we established an in-vitro scenario of calcium depletion.
    RESULTS: This study demonstrated that calcium deficiency reduces catalase activity, resulting in increased ROS accumulation in peroxisomes. This, in turn, inhibits mTORC1 and induces pexophagy through TFEB activation. However, treatment with the antioxidant N-acetyl-l-cysteine (NAC) and the autophagy inhibitor chloroquine impeded the nuclear translocation of TFEB and attenuated peroxisome degradation.
    CONCLUSIONS: Collectively, our study revealed that ROS-mediated TFEB activation triggers pexophagy during calcium deficiency, primarily because of attenuated catalase activity. We posit that calcium plays a significant role in the proper functioning of peroxisomes, critical for fatty-acid oxidation and ROS scavenging in maintaining cellular homeostasis. These findings have important implications for signaling mechanisms in various pathologies, including Zellweger's syndrome and ageing.
    Keywords:  Autophagy; Calcium; Catalase; Peroxisome; ROS; TFEB
    DOI:  https://doi.org/10.1186/s12964-024-01524-x
  4. Philos Trans R Soc Lond B Biol Sci. 2024 Apr 08. 379(1899): 20220381
    Lysosomal storage, impaired autophagy and innate immunity in Gaucher and Parkinson's diseases: insights for drug discovery.
    Alexander Hull, Magda L Atilano, Laith Gergi, Kerri J Kinghorn.
      Impairment of autophagic-lysosomal pathways is increasingly being implicated in Parkinson's disease (PD). GBA1 mutations cause the lysosomal storage disorder Gaucher disease (GD) and are the commonest known genetic risk factor for PD. GBA1 mutations have been shown to cause autophagic-lysosomal impairment. Defective autophagic degradation of unwanted cellular constituents is associated with several pathologies, including loss of normal protein homeostasis, particularly of α-synuclein, and innate immune dysfunction. The latter is observed both peripherally and centrally in PD and GD. Here, we will discuss the mechanistic links between autophagy and immune dysregulation, and the possible role of these pathologies in communication between the gut and brain in these disorders. Recent work in a fly model of neuronopathic GD (nGD) revealed intestinal autophagic defects leading to gastrointestinal dysfunction and immune activation. Rapamycin treatment partially reversed the autophagic block and reduced immune activity, in association with increased survival and improved locomotor performance. Alterations in the gut microbiome are a critical driver of neuroinflammation, and studies have revealed that eradication of the microbiome in nGD fly and mouse models of PD ameliorate brain inflammation. Following these observations, lysosomal-autophagic pathways, innate immune signalling and microbiome dysbiosis are discussed as potential therapeutic targets in PD and GD. This article is part of a discussion meeting issue 'Understanding the endo-lysosomal network in neurodegeneration'.
    Keywords:  Gaucher disease; Parkinson's disease; autophagy; immunity
    DOI:  https://doi.org/10.1098/rstb.2022.0381
  5. Front Immunol. 2024 ;15 1305157
    HCV-induced autophagy and innate immunity.
    Jiyoung Lee, J-H James Ou.
      The interplay between autophagy and host innate immunity has been of great interest. Hepatitis C virus (HCV) impedes signaling pathways initiated by pattern-recognition receptors (PRRs) that recognize pathogens-associated molecular patterns (PAMPs). Autophagy, a cellular catabolic process, delivers damaged organelles and protein aggregates to lysosomes for degradation and recycling. Autophagy is also an innate immune response of cells to trap pathogens in membrane vesicles for removal. However, HCV controls the autophagic pathway and uses autophagic membranes to enhance its replication. Mitophagy, a selective autophagy targeting mitochondria, alters the dynamics and metabolism of mitochondria, which play important roles in host antiviral responses. HCV also alters mitochondrial dynamics and promotes mitophagy to prevent premature cell death and attenuate the interferon (IFN) response. In addition, the dysregulation of the inflammasomal response by HCV leads to IFN resistance and immune tolerance. These immune evasion properties of HCV allow HCV to successfully replicate and persist in its host cells. In this article, we discuss HCV-induced autophagy/mitophagy and its associated immunological responses and provide a review of our current understanding of how these processes are regulated in HCV-infected cells.
    Keywords:  HCV; STING; autophagy; inflammasome; interferons; mitophagy; oxidative stress
    DOI:  https://doi.org/10.3389/fimmu.2024.1305157
  6. 3 Biotech. 2024 Mar;14(3): 87
    Autophagy: a necessary evil in cancer and inflammation.
    Amit Mathur, Ritu, Prakash Chandra, Asmita Das.
      Autophagy, a highly regulated cellular process, assumes a dual role in the context of cancer. On the one hand, it functions as a crucial homeostatic pathway, responsible for degrading malfunctioning molecules and organelles, thereby maintaining cellular health. On the other hand, its involvement in cancer development and regression is multifaceted, contingent upon a myriad of factors. This review meticulously examines the intricacies of autophagy, from its molecular machinery orchestrated by Autophagy-Related Genes (ATG) initially discovered in yeast to the various modes of autophagy operative within cells. Beyond its foundational role in cellular maintenance, autophagy reveals context-specific functions in processes like angiogenesis and inflammation. Our analysis delves into how autophagy-related factors directly impact inflammation, underscoring their profound implications for cancer dynamics. Additionally, we extend our inquiry to explore autophagy's associations with cardiovascular conditions, neurodegenerative disorders, and autoimmune diseases, illuminating the broader medical relevance of this process. Furthermore, this review elucidates how autophagy contributes to sustaining hallmark cancer features, including stem cell maintenance, proliferation, angiogenesis, metastasis, and metabolic reprogramming. Autophagy emerges as a pivotal process that necessitates careful consideration in cancer treatment strategies. To this end, we investigate innovative approaches, ranging from enzyme-based therapies to MTOR inhibitors, lysosomal blockers, and nanoparticle-enabled interventions, all aimed at optimizing cancer treatment outcomes by targeting autophagy pathways. In summary, this comprehensive review provides a nuanced perspective on the intricate and context-dependent role of autophagy in cancer biology. Our exploration not only deepens our understanding of this fundamental process but also highlights its potential as a therapeutic target. By unraveling the complex interplay between autophagy and cancer, we pave the way for more precise and effective cancer treatments, promising better outcomes for patients.
    Keywords:  Angiogenesis; Autophagy; Cancer; Endoplasmic reticulum; Inflammation; Nanoparticle
    DOI:  https://doi.org/10.1007/s13205-023-03864-w
  7. Int J Mol Sci. 2024 Feb 10. pii: 2139. [Epub ahead of print]25(4):
    THSD1 Suppresses Autophagy-Mediated Focal Adhesion Turnover by Modulating the FAK-Beclin 1 Pathway.
    Zhen Xu, Jiayi Lu, Song Gao, Yan-Ning Rui.
      Focal adhesions (FAs) play a crucial role in cell spreading and adhesion, and their autophagic degradation is an emerging area of interest. This study investigates the role of Thrombospondin Type 1 Domain-Containing Protein 1 (THSD1) in regulating autophagy and FA stability in brain endothelial cells, shedding light on its potential implications for cerebrovascular diseases. Our research reveals a physical interaction between THSD1 and FAs. Depletion of THSD1 significantly reduces FA numbers, impairing cell spreading and adhesion. The loss of THSD1 also induces autophagy independently of changes in mTOR and AMPK activation, implying that THSD1 primarily governs FA dynamics rather than serving as a global regulator of nutrient and energy status. Mechanistically, THSD1 negatively regulates Beclin 1, a central autophagy regulator, at FAs through interactions with focal adhesion kinase (FAK). THSD1 inactivation diminishes FAK activity and relieves its inhibitory phosphorylation on Beclin 1. This, in turn, promotes the complex formation between Beclin 1 and ATG14, a critical event for the activation of the autophagy cascade. In summary, our findings identify THSD1 as a novel regulator of autophagy that degrades FAs in brain endothelial cells. This underscores the distinctive nature of THSD1-mediated, cargo-directed autophagy and its potential relevance to vascular diseases due to the loss of endothelial FAs. Investigating the underlying mechanisms of THSD1-mediated pathways holds promise for discovering novel therapeutic targets in vascular diseases.
    Keywords:  Beclin 1; THSD1; autophagy; endothelial cells; focal adhesions
    DOI:  https://doi.org/10.3390/ijms25042139
  8. Cell Death Dis. 2024 Feb 21. 15(2): 161
    Advanced oxidation protein products attenuate the autophagy-lysosome pathway in ovarian granulosa cells by modulating the ROS-dependent mTOR-TFEB pathway.
    Xing-Yu Zhou, Yun-Hui Lai, Jun Zhang, Ying Li, Xiao-Min Wu, Yi-Zhen Yang, Xiao-Fei Zhang, Lin-Zi Ma, Ke-Ming Zheng, Yu-Dong Liu, Zhe Wang, Shi-Ling Chen.
      Oxidative stress dysfunction has recently been found to be involved in the pathogenesis of premature ovarian insufficiency (POI). Previously, we found that advanced oxidation protein products (AOPPs) in plasma were elevated in women with POI and had an adverse effect on granulosa cell proliferation. However, the mechanism underlying the effects of AOPPs on autophagy-lysosome pathway regulation in granulosa cells remains unclear. In this study, the effect of AOPPs on autophagy and lysosomal biogenesis and the underlying mechanisms were explored by a series of in vitro experiments in KGN and COV434 cell lines. AOPP-treated rat models were employed to determine the negative effect of AOPPs on the autophagy-lysosome systems in vivo. We found that increased AOPP levels activated the mammalian target of rapamycin (mTOR) pathway, and inhibited the autophagic response and lysosomal biogenesis in KGN and COV434 cells. Furthermore, scavenging of reactive oxygen species (ROS) with N-acetylcysteine and blockade of the mTOR pathway with rapamycin or via starvation alleviated the AOPP-induced inhibitory effects on autophagy and lysosomal biogenesis, suggesting that these effects of AOPPs are ROS-mTOR dependent. The protein expression and nuclear translocation of transcription factor EB (TFEB), the key regulator of lysosomal and autophagic function, were also impaired by the AOPP-activated ROS-mTOR pathway. In addition, TFEB overexpression attenuated the AOPP-induced impairment of autophagic flux and lysosomal biogenesis in KGN and COV434 cells. Chronic AOPP stimulation in vivo also impaired autophagy and lysosomal biogenesis in granulosa cells of rat ovaries. The results highlight that AOPPs lead to impairment of autophagic flux and lysosomal biogenesis via ROS-mTOR-TFEB signaling in granulosa cells and participate in the pathogenesis of POI.
    DOI:  https://doi.org/10.1038/s41419-024-06540-w
  9. Nat Commun. 2024 Feb 19. 15(1): 1516
    A SPLICS reporter reveals [Formula: see text]-synuclein regulation of lysosome-mitochondria contacts which affects TFEB nuclear translocation.
    Flavia Giamogante, Lucia Barazzuol, Francesca Maiorca, Elena Poggio, Alessandra Esposito, Anna Masato, Gennaro Napolitano, Alessio Vagnoni, Tito Calì, Marisa Brini.
      Mitochondrial and lysosomal activities are crucial to maintain cellular homeostasis: optimal coordination is achieved at their membrane contact sites where distinct protein machineries regulate organelle network dynamics, ions and metabolites exchange. Here we describe a genetically encoded SPLICS reporter for short- and long- juxtapositions between mitochondria and lysosomes. We report the existence of narrow and wide lysosome-mitochondria contacts differently modulated by mitophagy, autophagy and genetic manipulation of tethering factors. The overexpression of α-synuclein (α-syn) reduces the apposition of mitochondria/lysosomes membranes and affects their privileged Ca2+ transfer, impinging on TFEB nuclear translocation. We observe enhanced TFEB nuclear translocation in α-syn-overexpressing cells. We propose that α-syn, by interfering with mitochondria/lysosomes tethering impacts on local Ca2+ regulated pathways, among which TFEB mediated signaling, and in turn mitochondrial and lysosomal function. Defects in mitochondria and lysosome represent a common hallmark of neurodegenerative diseases: targeting their communication could open therapeutic avenues.
    DOI:  https://doi.org/10.1038/s41467-024-46007-2
  10. Philos Trans R Soc Lond B Biol Sci. 2024 Apr 08. 379(1899): 20220384
    VPS35 and retromer dysfunction in Parkinson's disease.
    Jordan Rowlands, Darren J Moore.
      The vacuolar protein sorting 35 ortholog (VPS35) gene encodes a core component of the retromer complex essential for the endosomal sorting and recycling of transmembrane cargo. Endo-lysosomal pathway deficits are suggested to play a role in the pathogenesis of neurodegenerative diseases, including Parkinson's disease (PD). Mutations in VPS35 cause a late-onset, autosomal dominant form of PD, with a single missense mutation (D620N) shown to segregate with disease in PD families. Understanding how the PD-linked D620N mutation causes retromer dysfunction will provide valuable insight into the pathophysiology of PD and may advance the identification of therapeutics. D620N VPS35 can induce LRRK2 hyperactivation and impair endosomal recruitment of the WASH complex but is also linked to mitochondrial and autophagy-lysosomal pathway dysfunction and altered neurotransmitter receptor transport. The clinical similarities between VPS35-linked PD and sporadic PD suggest that defects observed in cellular and animal models with the D620N VPS35 mutation may provide valuable insights into sporadic disease. In this review, we highlight the current knowledge surrounding VPS35 and its role in retromer dysfunction in PD. We provide a critical discussion of the mechanisms implicated in VPS35-mediated neurodegeneration in PD, as well as the interplay between VPS35 and other PD-linked gene products. This article is part of a discussion meeting issue 'Understanding the endo-lysosomal network in neurodegeneration'.
    Keywords:  Parkinson's disease (PD); VPS35; endosome; lysosome; retromer; vesicular sorting
    DOI:  https://doi.org/10.1098/rstb.2022.0384
  11. J Biol Chem. 2024 Feb 21. pii: S0021-9258(24)00154-6. [Epub ahead of print] 105778
    SUMO Modifies GβL and Mediates mTOR Signaling.
    Sophia Louise Lucille Park, Uri Nimrod Ramírez-Jarquín, Neelam Shahani, Oscar Rivera, Manish Sharma, Preksha Sandipkumar Joshi, Aayushi Hansalia, Sunayana Dagar, Francis P McManus, Pierre Thibault, Srinivasa Subramaniam.
      The mechanistic target of rapamycin (mTOR) signaling is influenced by multiple regulatory proteins and post-translational modifications, however, underlying mechanisms remain unclear. Here, we report a novel role of small ubiquitin-like modifier (SUMO) in mTOR complex assembly and activity. By investigating the SUMOylation status of core mTOR components, we observed that the regulatory subunit, GβL, is modified by SUMO1, 2, and 3 isoforms. Using mutagenesis and mass spectrometry, we identified that GβL is SUMOylated at lysine sites K86, K215, K245, K261 and K305. We found that SUMO depletion reduces mTOR-Raptor and mTOR-Rictor complex formation and diminishes nutrient-induced mTOR signaling. Reconstitution with WT GβL but not SUMOylation defective KR mutant GβL promote mTOR signaling in GβL-depleted cells. Furthermore, we found that amino acids-induced mTORC1 signaling is diminished in the SUMO1-KO mice. Taken together, we report for the very first time that SUMO modifies GβL, influences the assembly of mTOR protein complexes, and regulates mTOR activity.
    Keywords:  Amino acid stimulation; Kinase signaling; Lysine-site regulation; Nutrient signaling; Post-translational modification; Protein-protein interaction; SUMO isoforms; SUMO mechanism; Sumo interactive motif (SIM)
    DOI:  https://doi.org/10.1016/j.jbc.2024.105778
  12. Biomolecules. 2024 Jan 30. pii: 162. [Epub ahead of print]14(2):
    Mitochondrial Dysfunction and Protein Homeostasis in Aging: Insights from a Premature-Aging Mouse Model.
    Jaime M Ross, Lars Olson, Giuseppe Coppotelli.
      Mitochondrial dysfunction has been implicated in aging and age-related disorders. Disturbed-protein homeostasis and clearance of damaged proteins have also been linked to aging, as well as to neurodegenerative diseases, cancers, and metabolic disorders. However, since mitochondrial oxidative phosphorylation, ubiquitin-proteasome, and autophagy-lysosome systems are tightly interdependent, it is not understood whether the facets observed in aging are the causes or consequences of one or all of these failed processes. We therefore used prematurely aging mtDNA-mutator mice and normally aging wild-type littermates to elucidate whether mitochondrial dysfunction per se is sufficient to impair cellular protein homeostasis similarly to that which is observed in aging. We found that both mitochondrial dysfunction and normal aging affect the ubiquitin-proteasome system in a tissue-dependent manner, whereas only normal aging markedly impairs the autophagy-lysosome system. Thus, our data show that the proteostasis network control in the prematurely aging mtDNA-mutator mouse differs in certain aspects from that found in normal aging. Taken together, our findings suggest that severe mitochondrial dysfunction drives an aging phenotype associated with the impairment of certain components of the protein homeostasis machinery, while others, such as the autophagy-lysosome system, are not affected or only minimally affected. Taken together, this shows that aging is a multifactorial process resulting from alterations of several integrated biological processes; thus, manipulating one process at the time might not be sufficient to fully recapitulate all changes associated with normal aging.
    Keywords:  aging; autophagy; mitochondrial dysfunction; ubiquitin–proteasome system
    DOI:  https://doi.org/10.3390/biom14020162
  13. Biomedicines. 2024 Jan 23. pii: 257. [Epub ahead of print]12(2):
    The Role of Chaperone-Mediated Autophagy in Tissue Homeostasis and Disease Pathogenesis.
    Rut Valdor, Marta Martinez-Vicente.
      Chaperone-mediated autophagy (CMA) is a selective proteolytic pathway in the lysosomes. Proteins are recognized one by one through the detection of a KFERQ motif or, at least, a KFERQ-like motif, by a heat shock cognate protein 70 (Hsc70), a molecular chaperone. CMA substrates are recognized and delivered to a lysosomal CMA receptor, lysosome-associated membrane protein 2A (LAMP-2A), the only limiting component of this pathway, and transported to the lysosomal lumen with the help of another resident chaperone HSp90. Since approximately 75% of proteins are reported to have canonical, phosphorylation-generated, or acetylation-generated KFERQ motifs, CMA maintains intracellular protein homeostasis and regulates specific functions in the cells in different tissues. CMA also regulates physiologic functions in different organs, and is then implicated in disease pathogenesis related to aging, cancer, and the central nervous and immune systems. In this minireview, we have summarized the most important findings on the role of CMA in tissue homeostasis and disease pathogenesis, updating the recent advances for this Special Issue.
    Keywords:  chaperone-mediated autophagy; disease; homeostasis; pathogenesis
    DOI:  https://doi.org/10.3390/biomedicines12020257
  14. Int J Mol Sci. 2024 Feb 08. pii: 2068. [Epub ahead of print]25(4):
    GATOR1 Mutations Impair PI3 Kinase-Dependent Growth Factor Signaling Regulation of mTORC1.
    Maéline Muller, Jasmine Bélanger, Imane Hadj-Aissa, Conghao Zhang, Chantelle F Sephton, Paul A Dutchak.
      GATOR1 (GAP Activity TOward Rag 1) is an evolutionarily conserved GTPase-activating protein complex that controls the activity of mTORC1 (mammalian Target Of Rapamycin Complex 1) in response to amino acid availability in cells. Genetic mutations in the GATOR1 subunits, NPRL2 (nitrogen permease regulator-like 2), NPRL3 (nitrogen permease regulator-like 3), and DEPDC5 (DEP domain containing 5), have been associated with epilepsy in humans; however, the specific effects of these mutations on GATOR1 function and mTORC1 regulation are not well understood. Herein, we report that epilepsy-linked mutations in the NPRL2 subunit of GATOR1, NPRL2-L105P, -T110S, and -D214H, increase basal mTORC1 signal transduction in cells. Notably, we show that NPRL2-L105P is a loss-of-function mutation that disrupts protein interactions with NPRL3 and DEPDC5, impairing GATOR1 complex assembly and resulting in high mTORC1 activity even under conditions of amino acid deprivation. Furthermore, our studies reveal that the GATOR1 complex is necessary for the rapid and robust inhibition of mTORC1 in response to growth factor withdrawal or pharmacological inhibition of phosphatidylinositol-3 kinase (PI3K). In the absence of the GATOR1 complex, cells are refractory to PI3K-dependent inhibition of mTORC1, permitting sustained translation and restricting the nuclear localization of TFEB, a transcription factor regulated by mTORC1. Collectively, our results show that epilepsy-linked mutations in NPRL2 can block GATOR1 complex assembly and restrict the appropriate regulation of mTORC1 by canonical PI3K-dependent growth factor signaling in the presence or absence of amino acids.
    Keywords:  GATOR1; NPRL2; NPRL3; PI3 kinase; amino acids; epilepsy; growth factor signaling; mTORC1; metabolism; transcription; translation
    DOI:  https://doi.org/10.3390/ijms25042068
  15. J Cell Sci. 2024 Feb 15. pii: jcs261655. [Epub ahead of print]137(4):
    Going through changes - the role of autophagy during reprogramming and differentiation.
    Morten Petersen, Elise Ebstrup, Eleazar Rodriguez.
      Somatic cell reprogramming is a complex feature that allows differentiated cells to undergo fate changes into different cell types. This process, which is conserved between plants and animals, is often achieved via dedifferentiation into pluripotent stem cells, which have the ability to generate all other types of cells and tissues of a given organism. Cellular reprogramming is thus a complex process that requires extensive modification at the epigenetic and transcriptional level, unlocking cellular programs that allow cells to acquire pluripotency. In addition to alterations in the gene expression profile, cellular reprogramming requires rearrangement of the proteome, organelles and metabolism, but these changes are comparatively less studied. In this context, autophagy, a cellular catabolic process that participates in the recycling of intracellular constituents, has the capacity to affect different aspects of cellular reprogramming, including the removal of protein signatures that might hamper reprogramming, mitophagy associated with metabolic reprogramming, and the supply of energy and metabolic building blocks to cells that undergo fate changes. In this Review, we discuss advances in our understanding of the role of autophagy during cellular reprogramming by drawing comparisons between plant and animal studies, as well as highlighting aspects of the topic that warrant further research.
    Keywords:  Autophagy; Plant science; Regeneration; Reprogramming; Somatic reprogramming; Stem cells
    DOI:  https://doi.org/10.1242/jcs.261655
  16. Autophagy. 2024 Feb 21. 1-3
    Selective degradation of ribosomes during oncogene-induced senescence: molecular insights and biological perspectives.
    Aida Rodríguez López, Lisa B Frankel.
      Ribosomes are conserved macromolecular machines that are responsible for protein synthesis in all cells. While our knowledge of ribosome biogenesis and function has increased significantly in recent years, little is known about how ribosomes are degraded under specific cellular conditions. We recently uncovered that ribosomes are efficiently turned over by selective macroautophagy/autophagy during oncogene-induced senescence (OIS). By profiling the ribosome interactome in human fibroblasts undergoing OIS, we discovered a key role for the de-ubiquitinating enzyme USP10 in guiding this process. Release of USP10 from ribosomes during senescence leads to their enhanced ubiquitination and selective sequestering by autophagy through the SQSTM1/p62 receptor protein. This process is important for sustaining senescence-associated metabolome and secretome alterations.
    Keywords:  Oncogene-induced senescence; USP10; ribosomes; selective autophagy; translation; ubiquitination
    DOI:  https://doi.org/10.1080/15548627.2024.2319022
  17. Front Cell Dev Biol. 2024 ;12 1327167
    When autophagy meets placenta development and pregnancy complications.
    Pei Zhou, Junqi Wang, Jun Wang, Xiaomei Liu.
      Autophagy is a common biological phenomenon in eukaryotes that has evolved and reshaped to maintain cellular homeostasis. Under the pressure of starvation, hypoxia, and immune damage, autophagy provides energy and nutrients to cells, which benefits cell survival. In mammals, autophagy is an early embryonic nutrient supply system involved in early embryonic development, implantation, and pregnancy maintenance. Recent studies have found that autophagy imbalance in placental tissue plays a key role in the occurrence and development of pregnancy complications, such as gestational hypertension, gestational obesity, premature birth, miscarriage, and intrauterine growth restriction. This mini-review summarizes the molecular mechanism of autophagy regulation, the autophagy pathways, and related factors involved in placental tissue and comprehensively describes the role of autophagy in pregnancy complications.
    Keywords:  autophagy; gestational hypertension (GH); intrauterine growth restriction (IUGR); placenta; pregnancy complications
    DOI:  https://doi.org/10.3389/fcell.2024.1327167
  18. Eur Rev Med Pharmacol Sci. 2024 Feb;pii: 35332. [Epub ahead of print]28(3): 949-958
    YAP knockdown repressed autophagy in fibroblasts to accelerate wound healing through regulating En1/mTOR axis.
    C-J Chen, K Kishi.
       OBJECTIVE: Wound repair dysfunction is becoming a major public health issue worldwide. Yes-associated protein (YAP) has previously been reported to be closely related to wound healing, while how YAP accelerates wound healing via regulating autophagy needs to be further probed.
    MATERIALS AND METHODS: ICR male mice were involved in two independent animal experiments; the mice were randomly allocated into control, autophagy inhibitor (3-MA) (injection), and 3-MA (drip) group or control, si-NC, si-YAP group (8 mice for each). Full-thickness excisional wounds (8 mm) in mice were created by punch to construct an in vivo wound model to observe the effects of autophagy inhibitor (3-MA) (by injection and drip) and si-YAP by electrotransfection.
    RESULTS: Firstly, we found that the autophagy inhibitor (3-MA) accelerated wound closure in vivo. Loss-of-function experiments subsequently revealed that YAP knockdown led to increased proliferation and migration of fibroblasts as well as reduced autophagy, resulting in accelerated wound healing. In addition, our results revealed that YAP could positively regulate Engrailed-1 (En1) expression in fibroblasts. En1 knockdown also promoted the proliferation and migration of fibroblasts, meanwhile resulting in increased mammalian target of rapamycin (mTOR) levels and reduced autophagy in fibroblasts.
    CONCLUSIONS: YAP knockdown repressed autophagy in fibroblasts to accelerate wound closure by regulating the En1/mTOR axis.
    DOI:  https://doi.org/10.26355/eurrev_202402_35332
  19. Clin Pract. 2024 Feb 06. 14(1): 293-304
    Autophagy Genes and Otitis Media Outcomes.
    Yong Jun Kim, Hwa Sung Rim, Jeong Hee Kim, Sung Soo Kim, Joon Hyung Yeo, Seung Geun Yeo.
      Otitis media (OM) is a common cause of hearing loss in children that requires corrective surgery. Various studies have investigated the pathomechanisms and treatment of OM. Autophagy, an essential cellular recycling and elimination mechanism implicated in various diseases, is known to play an important role in the pathogenesis of OM. Here, we conducted a literature review on autophagy in OM, highlighting the relationship between expression patterns of autophagy-related factors and pathophysiological and clinical aspects of OM. We summarized the existing research results on the expression of autophagy-related factors in acute OM (AOM), OM with effusion (OME), chronic OM (COM) with cholesteatoma, and COM without cholesteatoma (CholeOM) in animals and humans. Autophagy-related factors are expressed in the middle ear mucosa or fluid of AOM, effusion of OME, granulation tissue of COM, and cholesteatoma of CholeOM. Among ATGs and other autophagy-related factors, the most extensively studied in relation to the pathogenesis of OM are mTOR, LC3II/I, PI3K, Beclin-1, FLIP, Akt, and Rubicon. Expression of autophagy-related factors is associated with AOM, OME, COM, and CholeOM. Inadequate expression of these factors or a decrease/increase in autophagy responses can result in OM, underscoring the critical role of ATGs and related factors in the pathogenesis of OM.
    Keywords:  autophagy; autophagy-related genes; cholesteatoma; effusion; granulation tissue; otitis media
    DOI:  https://doi.org/10.3390/clinpract14010023
  20. Biosci Rep. 2024 Feb 19. pii: BSR20240038. [Epub ahead of print]
    New insights into GATOR2-dependent interactions and its conformational changes in amino acid sensing.
    Can Yang, Xuan Sun, Geng Wu.
      Eukaryotic cells coordinate growth under different environmental conditions via mechanistic target of rapamycin complex 1 (mTORC1). In the amino-acid-sensing signaling pathway, the GATOR2 complex, containing five evolutionarily conserved subunits (WDR59, Mios, WDR24, Seh1L and Sec13), is required to regulate mTORC1 activity by interacting with upstream CASTOR1 (arginine sensor) and Sestrin2 (leucine sensor and downstream GATOR1 complex. GATOR2 complex utilises β-propellers to engage with CASTOR1, Sestrin2, and GATOR1, removal of these β-propellers results in substantial loss of mTORC1 capacity. However, structural information regarding the interface between amino acid sensors and GATOR2 remains elusive. With the recent progress of the AI-based tool AlphaFold2 (AF2) for protein structure prediction, structural models were predicted for Sentrin2-WDR24-Seh1L, and CASTOR1-Mios β-propeller. Furthermore, the effectiveness of relevant residues within the interface was examined using biochemical experiments combined with molecular dynamics (MD) simulations. Notably, fluorescence resonance energy transfer (FRET) analysis detected the structural transition of GATOR2 in response to amino acid signals, and the deletion of Mios β-propeller severely impeded that change at distinct arginine levels. These findings provide structural perspectives on the association between GATOR2 and amino acid sensors, and can facilitate future research on structure determination and function.
    Keywords:  AlphaFold2-Multimer prediction; GATOR2; amino acid sensing; amino acid sensors; conformational change; mTORC1
    DOI:  https://doi.org/10.1042/BSR20240038
  21. Cell Rep. 2024 Feb 16. pii: S2211-1247(24)00136-0. [Epub ahead of print]43(2): 113808
    UDP-glucose dehydrogenase supports autophagy-deficient PDAC growth via increasing hyaluronic acid biosynthesis.
    Minghe Fan, Sihan Huo, Yuyao Guo, Ruoxuan Wang, Wenqin Hao, Ziyang Zhang, Lina Wang, Ying Zhao.
      Autophagy is an essential degradation and recycling process that maintains cellular homeostasis during stress or nutrient deprivation. However, certain types of tumors such as pancreatic cancers can circumvent autophagy inhibition to sustain growth. The mechanism that autophagy-deficient pancreatic ductal adenocarcinoma (PDAC) uses to grow under nutrient deprivation is poorly understood. Our data show that nutrient deprivation in PDAC results in UDP-glucose dehydrogenase (UGDH) degradation, which is dependent on autophagic cargo receptor sequestosome 1 (p62). Moreover, we demonstrate that accumulated UGDH is indispensable for autophagy-deficient PDAC cells proliferation by promoting hyaluronic acid (HA) synthesis upon energy deprivation. Using an orthotopic mouse model of PDAC, we find that inhibition of HA synthesis by targeting UGDH in PDAC reduces tumor weight. Thus, the combined inhibition of HA and autophagy might be an attractive strategy for PDAC treatment.
    Keywords:  CP: Cancer; CP: Metabolism; HA; PDAC; UDP-glucose dehydrogenase; UGDH; autophagy; hyaluronic acid; p62; pancreatic ductal adenocarcinoma; sequestosome 1
    DOI:  https://doi.org/10.1016/j.celrep.2024.113808
  22. Biomedicines. 2024 Feb 19. pii: 462. [Epub ahead of print]12(2):
    The Role of Autophagy in Human Uveal Melanoma and the Development of Potential Disease Biomarkers and Novel Therapeutic Paradigms.
    Janney Z Wang, Paus Paulus, Yihe Niu, Ling Zhu, Christophe Morisseau, Tristan Rawling, Michael Murray, Bruce D Hammock, Fanfan Zhou.
      Autophagy is a form of programmed cell degradation that enables the maintenance of homeostasis in response to extracellular stress stimuli. Autophagy is primarily activated by starvation and mediates the degradation, removal, or recycling of cell cytoplasm, organelles, and intracellular components in eukaryotic cells. Autophagy is also involved in the pathogenesis of human diseases, including several cancers. Human uveal melanoma (UM) is the primary intraocular malignancy in adults and has an extremely poor prognosis; at present there are no effective therapies. Several studies have suggested that autophagy is important in UM. By understanding the mechanisms of activation of autophagy in UM it may be possible to develop biomarkers to provide more definitive disease prognoses and to identify potential drug targets for the development of new therapeutic strategies. This article reviews the current information regarding autophagy in UM that could facilitate biomarker and drug development.
    Keywords:  autophagy; biomarker; drug development; uveal melanoma
    DOI:  https://doi.org/10.3390/biomedicines12020462
  23. Cancers (Basel). 2024 Feb 16. pii: 807. [Epub ahead of print]16(4):
    Contribution of Autophagy to Epithelial Mesenchymal Transition Induction during Cancer Progression.
    Raffaele Strippoli, Reyhaneh Niayesh-Mehr, Maryam Adelipour, Arezoo Khosravi, Marco Cordani, Ali Zarrabi, Abdolamir Allameh.
      Epithelial Mesenchymal Transition (EMT) is a dedifferentiation process implicated in many physio-pathological conditions including tumor transformation. EMT is regulated by several extracellular mediators and under certain conditions it can be reversible. Autophagy is a conserved catabolic process in which intracellular components such as protein/DNA aggregates and abnormal organelles are degraded in specific lysosomes. In cancer, autophagy plays a controversial role, acting in different conditions as both a tumor suppressor and a tumor-promoting mechanism. Experimental evidence shows that deep interrelations exist between EMT and autophagy-related pathways. Although this interplay has already been analyzed in previous studies, understanding mechanisms and the translational implications of autophagy/EMT need further study. The role of autophagy in EMT is not limited to morphological changes, but activation of autophagy could be important to DNA repair/damage system, cell adhesion molecules, and cell proliferation and differentiation processes. Based on this, both autophagy and EMT and related pathways are now considered as targets for cancer therapy. In this review article, the contribution of autophagy to EMT and progression of cancer is discussed. This article also describes the multiple connections between EMT and autophagy and their implication in cancer treatment.
    Keywords:  autophagy; cell adhesion molecules; cell death; cell proliferation; differentiation; epithelial mesenchymal transition
    DOI:  https://doi.org/10.3390/cancers16040807
  24. Biochem Pharmacol. 2024 Feb 21. pii: S0006-2952(24)00058-3. [Epub ahead of print] 116075
    Targeting autophagy by antipsychotic phenothiazines: potential drug repurposing for cancer therapy.
    Rayssa M Lopes, Ana Carolina S Souza, Michał Otręba, Anna Rzepecka-Stojko, Ivarne L S Tersariol, Tiago Rodrigues.
      Cancer is recognized as the major cause of death worldwide and the most challenging public health issues. Tumor cells exhibit molecular adaptations and metabolic reprograming to sustain their high proliferative rate and autophagy plays a pivotal role to supply the high demand for metabolic substrates and for recycling cellular components, which has attracted the attention of the researchers. The modulation of the autophagic process sensitizes tumor cells to chemotherapy-induced cell death and reverts drug resistance. In this regard, many in vitro and in vivo studies having shown the anticancer activity of phenothiazine (PTZ) derivatives due to their potent cytotoxicity in tumor cells. Interestingly, PTZ have been used as antiemetics in antitumor chemotherapy-induced vomiting, maybe exerting a combined antitumor effect. Among the mechanisms of cytotoxicity, the modulation of autophagy by these drugs has been highlighted. Therefore, the use of PTZ derivatives can be considered as a repurposing strategy in antitumor chemotherapy. Here, we provided an overview of the effects of antipsychotic PTZ on autophagy in tumor cells, evidencing the molecular targets and discussing the underlying mechanisms. The modulation of autophagy by PTZ in tumor cells have been consistently related to their cytotoxic action. These effects depend on the derivative, their concentration, and also the type of cancer. Most data have shown the impairment of autophagic flux by PTZ, probably due to the blockade of lysosome-autophagosome fusion, but some studies have also suggested the induction of autophagy. These data highlight the therapeutic potential of targeting autophagy by PTZ in cancer chemotherapy.
    Keywords:  Autophagy; Cancer; Cell death; Chemotherapy; Drug repurposing; Phenothiazine
    DOI:  https://doi.org/10.1016/j.bcp.2024.116075
  25. Cancer Lett. 2024 Feb 15. pii: S0304-3835(24)00053-3. [Epub ahead of print] 216659
    Autophagy-driven regulation of cisplatin response in human cancers: Exploring molecular and cell death dynamics.
    Yang Yang, Lixia Liu, Yu Tian, Miaomiao Gu, Yanan Wang, Milad Ashrafizadeh, Amir Reza Aref, Israel Cañadas, Daniel J Klionsky, Arul Goel, Russel J Reiter, Yuzhuo Wang, Murtaza Tambuwala, Jianyong Zou.
      Despite the challenges posed by drug resistance and side effects, chemotherapy remains a pivotal strategy in cancer treatment. A key issue in this context is macroautophagy (commonly known as autophagy), a dysregulated cell death mechanism often observed during chemotherapy. Autophagy plays a cytoprotective role by maintaining cellular homeostasis and recycling organelles, and emerging evidence points to its significant role in promoting cancer progression. Cisplatin, a DNA-intercalating agent known for inducing cell death and cell cycle arrest, often encounters resistance in chemotherapy treatments. Recent studies have shown that autophagy can contribute to cisplatin resistance or insensitivity in tumor cells through various mechanisms. This resistance can be mediated by protective autophagy, which suppresses apoptosis. Additionally, autophagy-related changes in tumor cell metastasis, particularly the induction of Epithelial-Mesenchymal Transition (EMT), can also lead to cisplatin resistance. Nevertheless, pharmacological strategies targeting the regulation of autophagy and apoptosis offer promising avenues to enhance cisplatin sensitivity in cancer therapy. Notably, numerous non-coding RNAs have been identified as regulators of autophagy in the context of cisplatin chemotherapy. Thus, therapeutic targeting of autophagy or its associated pathways holds potential for restoring cisplatin sensitivity, highlighting an important direction for future clinical research.
    Keywords:  Apoptosis; Autophagy; Cancer chemotherapy; Cisplatin; Drug resistance
    DOI:  https://doi.org/10.1016/j.canlet.2024.216659
  26. Clin Exp Pharmacol Physiol. 2024 Apr;51(4): e13846
    Dapagliflozin alleviates high glucose-induced injury of endothelial cells via inducing autophagy.
    Gen Li, Ningxin Hou, Huagang Liu, Jun Li, Hongping Deng, Hongwen Lan, Sizheng Xiong.
      Hyperglycaemia is a key factor in the progression of diabetes complications. Dapagliflozin (DAPA), a new type of hypoglycaemic agent, has been shown to play an important role in anti-apoptotic, anti-inflammatory and antioxidant activities. Previous studies have demonstrated an endothelial protective effect of DAPA, but the underlying mechanism was still unclear. Autophagy is a homeostatic cellular mechanism that circulates unfolded proteins and damaged organelles through lysosomal dependent degradation. In this study, we aimed to investigate whether DAPA plays a protective role against high glucose (HG)-induced endothelial injury through regulating autophagy. The results showed that DAPA treatment resulted in increased cell viability. Additionally, DAPA treatment decreased interleukin (IL)-1β, IL-6, and tumour necrosis factor-α levels in endothelial cells subjected to HG conditions. We observed that HG inhibited autophagy, and DAPA increased the autophagy level by inhibiting the protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signalling pathway. Chloroquine reversed all of these beneficial effects as an autophagy inhibitor. In summary, the endothelial protective effect of DAPA in HG can be attributed in part to its role in activating of autophagy via the AKT/mTOR signalling pathway. Therefore, suggesting that the activation of autophagy by DAPA may be a novel target for the treatment of HG-induced endothelial cell injury.
    Keywords:  AKT/mTOR signalling pathway; autophagy; dapagliflozin; human umbilical vein endothelial cells
    DOI:  https://doi.org/10.1111/1440-1681.13846
  27. Nat Commun. 2024 Feb 23. 15(1): 1669
    Gonococcal OMV-delivered PorB induces epithelial cell mitophagy.
    Shuai Gao, Lingyu Gao, Dailin Yuan, Xu'ai Lin, Stijn van der Veen.
      The bacterial pathogen Neisseria gonorrhoeae is able to invade epithelial cells and survive intracellularly. During this process, it secretes outer membrane vesicles (OMVs), however, the mechanistic details for interactions between gonococcal OMVs and epithelial cells and their impact on intracellular survival are currently not established. Here, we show that gonococcal OMVs induce epithelial cell mitophagy to reduce mitochondrial secretion of reactive oxygen species (ROS) and enhance intracellular survival. We demonstrate that OMVs deliver PorB to mitochondria to dissipate the mitochondrial membrane potential, resulting in mitophagy induction through a conventional PINK1 and OPTN/NDP52 mechanism. Furthermore, PorB directly recruits the E3 ubiquitin ligase RNF213, which decorates PorB lysine residue 171 with K63-linked polyubiquitin to induce mitophagy in a p62-dependent manner. These results demonstrate a mechanism in which polyubiquitination of a bacterial virulence factor that targets mitochondria directs mitophagy processes to this organelle to prevent its secretion of deleterious ROS.
    DOI:  https://doi.org/10.1038/s41467-024-45961-1
  28. Microorganisms. 2024 Jan 30. pii: 296. [Epub ahead of print]12(2):
    Endothelial Mechanistic Target of Rapamycin Activation with Different Strains of R. rickettsii: Possible Role in Rickettsial Pathogenesis.
    Abha Sahni, Jessica Alsing, Hema P Narra, Michelle Montini, Yasim Zafar, Sanjeev K Sahni.
      Rickettsia rickettsii is an obligate intracellular pathogen that primarily targets endothelial cells (ECs), leading to vascular inflammation and dysfunction. Mechanistic target of rapamycin (mTOR) regulates several cellular processes that directly affect host immune responses to bacterial pathogens. Here, we infected ECs with two R. rickettsii strains, avirulent (Iowa) and highly virulent Sheila Smith (SS) to identify differences in the kinetics and/or intensity of mTOR activation to establish a correlation between mTOR response and bacterial virulence. Endothelial mTOR activation with the highly virulent SS strain was significantly higher than with the avirulent Iowa strain. Similarly, there was increased LC3-II lipidation with the virulent SS strain compared with the avirulent Iowa strain of R. rickettsii. mTOR inhibitors rapamycin and Torin2 significantly increased bacterial growth and replication in the ECs, as evidenced by a more than six-fold increase in rickettsia copy numbers at 48 h post-infection. Further, the knockdown of mTOR with Raptor and Rictor siRNA resulted in a higher rickettsial copy number and the altered expression of the pro-inflammatory cytokines interleukin (IL)-1α, IL-6, and IL-8. These results are the first to reveal that endothelial mTOR activation and the early induction of autophagy might be governed by bacterial virulence and have established the mTOR pathway as an important regulator of endothelial inflammation, host immunity, and microbial replication.
    Keywords:  Rickettsia; autophagy; endothelial cells; inflammation; mTOR
    DOI:  https://doi.org/10.3390/microorganisms12020296
  29. Life Sci Alliance. 2024 May;pii: e202302016. [Epub ahead of print]7(5):
    The RNA-binding protein Msi2 regulates autophagy during myogenic differentiation.
    Ruochong Wang, Futaba Kato, Rio Yasui Watson, Aaron M Beedle, Jarrod A Call, Yugo Tsunoda, Takeshi Noda, Takaho Tsuchiya, Makoto Kashima, Ayuna Hattori, Takahiro Ito.
      Skeletal muscle development is a highly ordered process orchestrated transcriptionally by the myogenic regulatory factors. However, the downstream molecular mechanisms of myogenic regulatory factor functions in myogenesis are not fully understood. Here, we identified the RNA-binding protein Musashi2 (Msi2) as a myogenin target gene and a post-transcriptional regulator of myoblast differentiation. Msi2 knockdown in murine myoblasts blocked differentiation without affecting the expression of MyoD or myogenin. Msi2 overexpression was also sufficient to promote myoblast differentiation and myocyte fusion. Msi2 loss attenuated autophagosome formation via down-regulation of the autophagic protein MAPL1LC3/ATG8 (LC3) at the early phase of myoblast differentiation. Moreover, forced activation of autophagy effectively suppressed the differentiation defects incurred by Msi2 loss. Consistent with its functions in myoblasts in vitro, mice deficient for Msi2 exhibited smaller limb skeletal muscles, poorer exercise performance, and muscle fiber-type switching in vivo. Collectively, our study demonstrates that Msi2 is a novel regulator of mammalian myogenesis and establishes a new functional link between muscular development and autophagy regulation.
    DOI:  https://doi.org/10.26508/lsa.202302016
  30. Autophagy. 2024 Feb 23.
    TRIM27 elicits protective immunity against tuberculosis by activating TFEB-mediated autophagy flux.
    Dongdong Zhao, Lihua Qiang, Zehui Lei, Pupu Ge, Zhe Lu, Yiru Wang, Xinwen Zhang, Yuyun Qiang, Bingxi Li, Yu Pang, Lingqiang Zhang, Cui Hua Liu, Jing Wang.
      Infectious diseases, such as Mycobacterium tuberculosis (Mtb)-caused tuberculosis (TB), remain a global threat exacerbated by increasing drug resistance. Host-directed therapy (HDT) is a promising strategy for infection treatment through targeting host immunity. However, the limited understanding of the function and regulatory mechanism of host factors involved in immune defense against infections has impeded HDT development. Here, we identify the ubiquitin ligase (E3) TRIM27 (tripartite motif-containing 27) as a host protective factor against Mtb by enhancing host macroautophagy/autophagy flux in an E3 ligase activity-independent manner. Mechanistically, upon Mtb infection, nuclear-localized TRIM27 increases and functions as a transcription activator of TFEB (transcription factor EB). Specifically, TRIM27 binds to the TFEB promoter and the TFEB transcription factor CREB1 (cAMP responsive element binding protein 1), thus enhancing CREB1-TFEB promoter binding affinity and promoting CREB1 transcription activity toward TFEB, eventually inducing autophagy-related gene expression as well as autophagy flux activation to clear the pathogen. Furthermore, TFEB activator 1 can rescue TRIM27 deficiency-caused decreased autophagy-related gene transcription and attenuated autophagy flux, and accordingly suppressed the intracellular survival of Mtb in cell and mouse models. Taken together, our data reveal that TRIM27 is a host defense factor against Mtb, and the TRIM27-CREB1-TFEB axis is a potential HDT-based TB target that can enhance host autophagy flux.
    Keywords:  Autophagy flux; Transcription factor EB; cAMP responsive element binding protein 1; mycobacterium tuberculosis; tripartite motif-containing 27; tuberculosis
    DOI:  https://doi.org/10.1080/15548627.2024.2321831
  31. Autophagy Rep. 2024 ;pii: 2306086. [Epub ahead of print]3(1):
    Autophagy Determines Distinct Cell Fates in Human Amnion and Chorion Cells.
    Mary Elise L Severino, Lauren Richardson, Ananth Kumar Kammala, Enkhtuya Radnaa, Kamil Khanipov, Leslie Michelle M Dalmacio, Indira U Mysorekar, Marian Kacerovsky, Ramkumar Menon.
      Human fetal membranes (amniochorion) that line the intrauterine cavity consist of two distinct cell layers; single-layer amnion epithelial cells (AEC) and multilayer chorion trophoblast cells (CTC). These layers are connected through a collagen-rich extracellular matrix. Cellular remodeling helps support membrane growth and integrity during gestation and helps to maintain pregnancy. Preterm prelabor rupture of the human amniochorionic (fetal) membrane (pPROM) is antecedent to 40% of all spontaneous preterm birth. Oxidative stress (OS) induced activation of the p38 MAPK due to various maternal risk exposures and the amniochorion cells' senescence are reported pathological features of pPROM. Our transcriptomics analysis implicated dysregulated autophagy and epithelial-mesenchymal transition (EMT) in fetal membranes from pPROM. The molecular interplay between OS-induced p38 MAPK activation, autophagy, and EMT was investigated in AECs and CTCs to better understand the involvement of autophagy and EMT. We report the differential impact of OS on the autophagic machinery in AECs and CTCs, resulting in distinct cell fates. In AECs, OS-induced p38 MAPK activation causes autophagosome accumulation and reduced autophagic flux mediated by decreased ULK1 activity and kinase activity, leading to senescence. In CTCs, induction of autophagy has a limited effect; however, inhibition of autophagy led to SQSTM1-mediated EMT of trophoblast cells. Autophagy, EMT, and senescence were associated with proinflammatory changes. Thus, AECs and CTCs respond differently to OS via differential autophagy response, partly mediated via p38 MAPK. Besides senescence, OS-induced autophagy dysregulation in amniochorion cells may play a mechanistic role in pPROM pathophysiology.
    Keywords:  Membrane rupture; Oxidative stress; amnion; autophagy; chorion; epithelial-mesenchymal transition; p38 MAPK; preterm birth; preterm premature rupture of membranes; senescence; trophoblast
    DOI:  https://doi.org/10.1080/27694127.2024.2306086
  32. Nat Commun. 2024 Feb 17. 15(1): 1460
    ALLO-1- and IKKE-1-dependent positive feedback mechanism promotes the initiation of paternal mitochondrial autophagy.
    Taeko Sasaki, Yasuharu Kushida, Takuya Norizuki, Hidetaka Kosako, Ken Sato, Miyuki Sato.
      Allophagy is responsible for the selective removal of paternally inherited organelles, including mitochondria, in Caenorhabditis elegans embryos, thereby facilitating the maternal inheritance of mitochondrial DNA. We previously identified two key factors in allophagy: an autophagy adaptor allophagy-1 (ALLO-1) and TBK1/IKKε family kinase IKKE-1. However, the precise mechanisms by which ALLO-1 and IKKE-1 regulate local autophagosome formation remain unclear. In this study, we identify two ALLO-1 isoforms with different substrate preferences during allophagy. Live imaging reveals a stepwise mechanism of ALLO-1 localization with rapid cargo recognition, followed by ALLO-1 accumulation around the cargo. In the ikke-1 mutant, the accumulation of ALLO-1, and not the recognition of cargo, is impaired, resulting in the failure of isolation membrane formation. Our results also suggest a feedback mechanism for ALLO-1 accumulation via EPG-7/ATG-11, a worm homolog of FIP200, which is a candidate for IKKE-1-dependent phosphorylation. This feedback mechanism may underlie the ALLO-1-dependent initiation and progression of autophagosome formation around paternal organelles.
    DOI:  https://doi.org/10.1038/s41467-024-45863-2
  33. Front Pharmacol. 2024 ;15 1344075
    Mitophagy regulates mitochondrial number following pharmacological induction of mitochondrial biogenesis in renal proximal tubule cells.
    Kevin A Hurtado, Rick G Schnellmann.
      Background: Mitochondrial biogenesis (MB) induction through the activation of the 5-Hydroxytriptamine (5-HT) 1F receptor (HTR1F) is a promising mechanism for the treatment of diseases characterized by mitochondrial dysfunction, such as acute kidney injury (AKI). While several studies report pharmacological activation of MB in the proximal tubule, it is unclear how the proximal tubule regulates itself once the pharmacological activation is removed. Mitophagy is the process of selective mitochondria degradation. We hypothesize that mitophagy decreases mitochondrial number after pharmacological stimulation and restore mitochondrial homeostasis. Methods: Renal proximal tubules were treated at time 0hr with LY344864 or vehicle for 24 h and then removed. LY344864, a selective HTR1F agonist, induces MB in renal proximal tubules as previously reported (Gibbs et al., Am J Physiol Renal Physiol, 2018, 314(2), F260-F268). Vehicle and pharmacological reagents were added at the 24 h time point. Electron microscopy was used to assess mitochondrial morphology, number, and autolysosomes. Seahorse Bioscience XF-96 extracellular flux analyzer was used to measure maximal mitochondrial oxygen consumption rates (FCCP-OCR), a functional marker of MB. Results: LY344864 treatment increased FCCP-OCR, phosphorylation of protein kinase B (AKT), peroxisome proliferator-activated receptor γ coactivator-1alpha (PGC-1α), and mitochondrial number after 24 h. These endpoints decreased to baseline 24 h after LY344864 removal. Treatment with ROC-325, an autophagy inhibitor, increased Sequestosome-1 (SQSTM1/P62) and microtubule-associated protein-1 light chain 3 (LC3B) after 24 h of treatment. Also, ROC-325 treatment sustained the elevated mitochondrial number after LY344864 pre-treatment and removal. Conclusion: These data revealed that inhibition of autophagy extends elevated mitochondrial number and function by preventing the lysosomal degradation of mitochondria after the removal of LY344864.
    Keywords:  HTR1F; autophagy; mitochondrial biogenesis; mitophagy; proximal tubule
    DOI:  https://doi.org/10.3389/fphar.2024.1344075
  34. Philos Trans R Soc Lond B Biol Sci. 2024 Apr 08. 379(1899): 20220376
    Retromer-dependent lysosomal stress in Parkinson's disease.
    Dario R Alessi, Peter J Cullen, Mark Cookson, Kalpana M Merchant, Scott A Small.
      While causative mutations in complex disorders are rare, they can be used to extract a biological pathway whose pathogenicity can generalize to common forms of the disease. Here we begin by relying on the biological consequences of mutations in LRRK2 and VPS35, genetic causes of autosomal-dominant Parkinson's disease, to hypothesize that 'Retromer-dependent lysosomal stress' represents a pathway that can generalize to idiopathic Parkinson's disease. Next, we outline a series of studies that can test this hypothesis, including the development of biomarkers of pathway dysfunction. If validated, the hypothesis can suggest a unified mechanism of disease and might inform future diagnostic and therapeutic investigations. This article is part of a discussion meeting issue 'Understanding the endo-lysosomal network in neurodegeneration'.
    Keywords:  LRRK2; Parkinson's disease; VPS35; retromer
    DOI:  https://doi.org/10.1098/rstb.2022.0376
  35. Int J Biol Macromol. 2024 Feb 15. pii: S0141-8130(24)01022-5. [Epub ahead of print] 130219
    Exploring the therapeutic potential of Rab11: A comprehensive study on its effectiveness in alleviating rotenone-induced molecular pathogenesis of Parkinson's disease in SH-SY5Y cells and its synergistic application with L-DOPA in Drosophila models.
    Pooja Rai, Sada Nand Pandey, Jagat Kumar Roy.
      Dysfunctional mitophagy contributes to Parkinson's disease (PD) by affecting dopamine-producing neurons. Mutations in parkin and pink1 genes, linked to familial PD, impede the removal of damaged mitochondria. Previous studies suggested Rab11's involvement in mitophagy alongside Parkin and Pink1. Additionally, mitochondria-endoplasmic reticulum contact sites (MERCS) regulate cellular functions, including mitochondrial quality control and calcium regulation. Our study explored whether activating mitophagy triggers the unfolded protein response and ER stress pathway in SH-SY5Y human cells. We induced a PD-like state by exposing undifferentiated SH-SY5Y cells to rotenone, an established PD-inducing agent. This led to reduced Rab11 and PERK- expression while increasing ATP5a, a mitochondrial marker, when Rab11 was overexpressed. Our findings suggest that enhancing endosomal trafficking can mitigate ER stress by regulating mitochondria, rescuing cells from apoptosis. Furthermore, we assessed the therapeutic potential of Rab11, both alone and in combination with L-Dopa, in a Drosophila PD model. In summary, our research underscores the role of mitophagy dysfunction in PD pathogenesis, highlighting Rab11's importance in alleviating ER stress and preserving mitochondrial function. It also provides insights into potential PD management strategies, including the synergistic use of Rab11 and L-Dopa.
    Keywords:  Drosophila; ER-stress; L-dopa; Mitochondria; Rab11; SH-SY5Y
    DOI:  https://doi.org/10.1016/j.ijbiomac.2024.130219
  36. Biomolecules. 2024 Feb 09. pii: 207. [Epub ahead of print]14(2):
    Inspiring Tactics with the Improvement of Mitophagy and Redox Balance for the Development of Innovative Treatment against Polycystic Kidney Disease.
    Moeka Nakashima, Naoko Suga, Yuka Ikeda, Sayuri Yoshikawa, Satoru Matsuda.
      Polycystic kidney disease (PKD) is the most common genetic form of chronic kidney disease (CKD), and it involves the development of multiple kidney cysts. Not enough medical breakthroughs have been made against PKD, a condition which features regional hypoxia and activation of the hypoxia-inducible factor (HIF) pathway. The following pathology of CKD can severely instigate kidney damage and/or renal failure. Significant evidence verifies an imperative role for mitophagy in normal kidney physiology and the pathology of CKD and/or PKD. Mitophagy serves as important component of mitochondrial quality control by removing impaired/dysfunctional mitochondria from the cell to warrant redox homeostasis and sustain cell viability. Interestingly, treatment with the peroxisome proliferator-activated receptor-α (PPAR-α) agonist could reduce the pathology of PDK and might improve the renal function of the disease via the modulation of mitophagy, as well as the condition of gut microbiome. Suitable modulation of mitophagy might be a favorable tactic for the prevention and/or treatment of kidney diseases such as PKD and CKD.
    Keywords:  adenosine monophosphate-activated protein kinase; autophagy; chronic kidney disease; gut microbiome; hypoxia; mitochondria; mitophagy; polycystic kidney disease
    DOI:  https://doi.org/10.3390/biom14020207
  37. Stem Cells Int. 2024 ;2024 3429565
    Different Levels of Autophagy Activity in Mesenchymal Stem Cells Are Involved in the Progression of Idiopathic Pulmonary Fibrosis.
    Hongxia Tao, Qin Lv, Jing Zhang, Lijuan Chen, Yang Yang, Wei Sun.
      Idiopathic pulmonary fibrosis (IPF) is an age-related lung interstitial disease that occurs predominantly in people over 65 years of age and for which there is a lack of effective therapeutic agents. It has demonstrated that mesenchymal stem cells (MSCs) including alveolar epithelial cells (AECs) can perform repair functions. However, MSCs lose their repair functions due to their distinctive aging characteristics, eventually leading to the progression of IPF. Recent breakthroughs have revealed that the degree of autophagic activity influences the renewal and aging of MSCs and determines the prognosis of IPF. Autophagy is a lysosome-dependent pathway that mediates the degradation and recycling of intracellular material and is an efficient way to renew the nonnuclear (cytoplasmic) part of eukaryotic cells, which is essential for maintaining cellular homeostasis and is a potential target for regulating MSCs function. Therefore, this review focuses on the changes in autophagic activity of MSCs, clarifies the relationship between autophagy and health status of MSCs and the effect of autophagic activity on MSCs senescence and IPF, providing a theoretical basis for promoting the clinical application of MSCs.
    DOI:  https://doi.org/10.1155/2024/3429565
  38. Philos Trans R Soc Lond B Biol Sci. 2024 Apr 08. 379(1899): 20220388
    Endo-lysosomal dysfunction and neuronal-glial crosstalk in Niemann-Pick type C disease.
    Mariagiovanna Malara, Matthias Prestel, Sabina Tahirovic.
      Niemann-Pick type C (NPC) disease is a rare progressive lysosomal lipid storage disorder that manifests with a heterogeneous spectrum of clinical syndromes, including visceral, neurological and psychiatric symptoms. This monogenetic autosomal recessive disease is largely caused by mutations in the NPC1 gene, which controls intracellular lipid homeostasis. Vesicle-mediated endo-lysosomal lipid trafficking and non-vesicular lipid exchange via inter-organelle membrane contact sites are both regulated by the NPC1 protein. Loss of NPC1 function therefore triggers intracellular accumulation of diverse lipid species, including cholesterol, glycosphingolipids, sphingomyelin and sphingosine. The NPC1-mediated dysfunction of lipid transport has severe consequences for all brain cells, leading to neurodegeneration. Besides the cell-autonomous contribution of neuronal NPC1, aberrant NPC1 signalling in other brain cells is critical for the pathology. We discuss here the importance of endo-lysosomal dysfunction and a tight crosstalk between neurons, oligodendrocytes, astrocytes and microglia in NPC pathology. We strongly believe that a cell-specific rescue may not be sufficient to counteract the severity of the NPC pathology, but targeting common mechanisms, such as endo-lysosomal and lipid trafficking dysfunction, may ameliorate NPC pathology. This article is part of a discussion meeting issue 'Understanding the endo-lysosomal network in neurodegeneration'.
    Keywords:  NPC1; cholesterol; endo-lysosomal trafficking; glia; neurons
    DOI:  https://doi.org/10.1098/rstb.2022.0388
  39. Commun Biol. 2024 Feb 20. 7(1): 209
    BECLIN1 is essential for intestinal homeostasis involving autophagy-independent mechanisms through its function in endocytic trafficking.
    Sharon Tran, Juliani Juliani, Tiffany J Harris, Marco Evangelista, Julian Ratcliffe, Sarah L Ellis, David Baloyan, Camilla M Reehorst, Rebecca Nightingale, Ian Y Luk, Laura J Jenkins, Sonia Ghilas, Marina H Yakou, Chantelle Inguanti, Chad Johnson, Michael Buchert, James C Lee, Peter De Cruz, Kinga Duszyc, Paul A Gleeson, Benjamin T Kile, Lisa A Mielke, Alpha S Yap, John M Mariadason, W Douglas Fairlie, Erinna F Lee.
      Autophagy-related genes have been closely associated with intestinal homeostasis. BECLIN1 is a component of Class III phosphatidylinositol 3-kinase complexes that orchestrate autophagy initiation and endocytic trafficking. Here we show intestinal epithelium-specific BECLIN1 deletion in adult mice leads to rapid fatal enteritis with compromised gut barrier integrity, highlighting its intrinsic critical role in gut maintenance. BECLIN1-deficient intestinal epithelial cells exhibit extensive apoptosis, impaired autophagy, and stressed endoplasmic reticulum and mitochondria. Remaining absorptive enterocytes and secretory cells display morphological abnormalities. Deletion of the autophagy regulator, ATG7, fails to elicit similar effects, suggesting additional novel autophagy-independent functions of BECLIN1 distinct from ATG7. Indeed, organoids derived from BECLIN1 KO mice show E-CADHERIN mislocalisation associated with abnormalities in the endocytic trafficking pathway. This provides a mechanism linking endocytic trafficking mediated by BECLIN1 and loss of intestinal barrier integrity. Our findings establish an indispensable role of BECLIN1 in maintaining mammalian intestinal homeostasis and uncover its involvement in endocytic trafficking in this process. Hence, this study has important implications for our understanding of intestinal pathophysiology.
    DOI:  https://doi.org/10.1038/s42003-024-05890-7
  40. Cell Biochem Biophys. 2024 Feb 21.
    Mitochondria, Autophagy and Inflammation: Interconnected in Aging.
    Rafael Cardoso Maciel Costa Silva.
      In this manuscript, I discuss the direct link between abnormalities in inflammatory responses, mitochondrial metabolism and autophagy during the process of aging. It is focused on the cytosolic receptors nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) and cyclic GMP-AMP synthase (cGAS); myeloid-derived suppressor cells (MDSCs) expansion and their associated immunosuppressive metabolite, methyl-glyoxal, all of them negatively regulated by mitochondrial autophagy, biogenesis, metabolic pathways and its distinct metabolites.
    Keywords:  Aging; MDSCs; Mitochondria; NAD+; NLRP3
    DOI:  https://doi.org/10.1007/s12013-024-01231-x
  41. Int J Mol Sci. 2024 Feb 08. pii: 2052. [Epub ahead of print]25(4):
    Mitochondrial Quantity and Quality in Age-Related Sarcopenia.
    Emanuele Marzetti, Riccardo Calvani, Hélio José Coelho-Júnior, Francesco Landi, Anna Picca.
      Sarcopenia, the age-associated decline in skeletal muscle mass and strength, is a condition with a complex pathophysiology. Among the factors underlying the development of sarcopenia are the progressive demise of motor neurons, the transition from fast to slow myosin isoform (type II to type I fiber switch), and the decrease in satellite cell number and function. Mitochondrial dysfunction has been indicated as a key contributor to skeletal myocyte decline and loss of physical performance with aging. Several systems have been implicated in the regulation of muscle plasticity and trophism such as the fine-tuned and complex regulation between the stimulator of protein synthesis, mechanistic target of rapamycin (mTOR), and the inhibitor of mTOR, AMP-activated protein kinase (AMPK), that promotes muscle catabolism. Here, we provide an overview of the molecular mechanisms linking mitochondrial signaling and quality with muscle homeostasis and performance and discuss the main pathways elicited by their imbalance during age-related muscle wasting. We also discuss lifestyle interventions (i.e., physical exercise and nutrition) that may be exploited to preserve mitochondrial function in the aged muscle. Finally, we illustrate the emerging possibility of rescuing muscle tissue homeostasis through mitochondrial transplantation.
    Keywords:  DAMPs; extracellular vesicles; inflammaging; metabolism; mitochondrial DNA; mitochondrial biogenesis; mitochondrial transplantation; mitophagy; muscle aging; muscle plasticity
    DOI:  https://doi.org/10.3390/ijms25042052
  42. Biomedicines. 2024 Feb 07. pii: 386. [Epub ahead of print]12(2):
    Sirtuins Affect Cancer Stem Cells via Epigenetic Regulation of Autophagy.
    Ferenc Sipos, Györgyi Műzes.
      Sirtuins (SIRTs) are stress-responsive proteins that regulate several post-translational modifications, partly by acetylation, deacetylation, and affecting DNA methylation. As a result, they significantly regulate several cellular processes. In essence, they prolong lifespan and control the occurrence of spontaneous tumor growth. Members of the SIRT family have the ability to govern embryonic, hematopoietic, and other adult stem cells in certain tissues and cell types in distinct ways. Likewise, they can have both pro-tumor and anti-tumor effects on cancer stem cells, contingent upon the specific tissue from which they originate. The impact of autophagy on cancer stem cells, which varies depending on the specific circumstances, is a very intricate phenomenon that has significant significance for clinical and therapeutic purposes. SIRTs exert an impact on the autophagy process, whereas autophagy reciprocally affects the activity of certain SIRTs. The mechanism behind this connection in cancer stem cells remains poorly understood. This review presents the latest findings that position SIRTs at the point where cancer cells and autophagy interact. Our objective is to highlight the various roles of distinct SIRTs in cancer stem cell-related functions through autophagy. This would demonstrate their significance in the genesis and recurrence of cancer and offer a more precise understanding of their treatment possibilities in relation to autophagy.
    Keywords:  DNA methylation; SIRT; acetylation; autophagy; cancer stem cells; deacetylation; epigenetics; sirtuins
    DOI:  https://doi.org/10.3390/biomedicines12020386
  43. Stem Cells. 2024 Feb 23. pii: sxae019. [Epub ahead of print]
    Empagliflozin ameliorates the impaired osteogenic differentiation ability of adipose-derived stem cells in diabetic osteoporosis by activating autophagy.
    Shuanglin Yang, Ya Lin, Yuping Xie, Ting Fu, Tianli Wu, Xiaorong Lan, Fangzhi Lou, Jingang Xiao.
      Adipose-derived stem cells (ASCs) from diabetic osteoporosis (DOP) mice showed impaired osteogenic differentiation capacity. Recent studies have shown that in addition to antidiabetic drugs, sodium-glucose co-transporter inhibitor-2 (SGLT-2), empagliflozin, can play multipotent roles through various mechanisms of action. In this study, we aimed to investigate the effects and underlying mechanisms of empagliflozin on osteogenic differentiation of ASCs in DOP mice. Our results showed that osteogenic differentiation potential and autophagy activity weakened in DOP-ASCs when compared to controls. However, empagliflozin enhanced autophagy flux by promoting the formation of autophagosomes and acidification of autophagic lysosomes, resulting in an increase in LC3-II expression and a decrease in SQSTM1 expression. Furthermore, empagliflozin contributed to the reversal of osteogenesis inhibition in DOP-ASCs induced by a diabetic microenvironment. When 3-methyladenine was used to block autophagy activity, empagliflozin could not exert its protective effect on DOP-ASCs. Nonetheless, this study demonstrated that the advent of cellular autophagy attributed to the administration of empagliflozin could ameliorate the impaired osteogenic differentiation potential of ASCs in DOP mice. This finding might be conducive to the application of ASCs transplantation for promoting bone fracture healing and bone regeneration in DOP patients.
    Keywords:  Adipose-derived stem cells; Autophagy; Diabetic osteoporosis; Empagliflozin; Osteogenic differentiation
    DOI:  https://doi.org/10.1093/stmcls/sxae019
  44. Kidney Int. 2024 Feb 20. pii: S0085-2538(24)00118-2. [Epub ahead of print]
    Disrupting circadian control of autophagy induces podocyte injury and proteinuria.
    Lulu Wang, Han Tian, Haiyan Wang, Xiaoming Mao, Jing Luo, Qingyun He, Ping Wen, Hongdi Cao, Li Fang, Yang Zhou, Junwei Yang, Lei Jiang.
      The circadian clock influences a wide range of biological process and controls numerous aspects of physiology to adapt to the daily environmental changes caused by Earth's rotation. The kidney clock plays an important role in maintaining tubular function, but its effect on podocytes remains unclear. Here, we found that podocytes expressed CLOCK proteins, and that 2666 glomerular gene transcripts (13.4%), including autophagy related genes, had 24-hour circadian rhythms. Deletion of Clock in podocytes resulted in 1666 gene transcripts with the loss of circadian rhythm including autophagy genes. Therefore, there was no decrease in their expression. Podocyte-specific Clock knockout mice at age three and eight months showed deficient autophagy, loss of podocytes and increased albuminuria. Chromatin immunoprecipitation (ChIP) sequence analysis indicated autophagy related genes were targets of CLOCK in podocytes. ChIP-PCR further confirmed Clock binding to the promoter regions of Becn1 and Atg12, two autophagy related genes. Furthermore, the association of CLOCK regulated autophagy with chronic sleep fragmentation and diabetic kidney disease was analyzed. Chronic sleep fragmentation resulted in the loss of glomerular Clock rhythm, inhibition of podocyte autophagy, and proteinuria. Rhythmic oscillations of Clock also disappeared in high glucose treated podocytes and in glomeruli from diabetic mice. Finally, circadian differences in podocyte autophagy were also abolished in diabetic mice. Deletion Clock in podocytes aggravated podocyte injury and proteinuria in diabetic mice. Thus, our findings demonstrate that clock-dependent regulation of autophagy may be essential for podocyte survival. Hence. loss of circadian controlled autophagy may play an important role in podocyte injury and proteinuria.
    Keywords:  Circadian; autophagy; podocyte; proteinuria
    DOI:  https://doi.org/10.1016/j.kint.2024.01.035
  45. Front Immunol. 2024 ;15 1308070
    The significance of targeting lysosomes in cancer immunotherapy.
    Yanxin Xu, Bo Shao, Yafeng Zhang.
      Lysosomes are intracellular digestive organelles that participate in various physiological and pathological processes, including the regulation of immune checkpoint molecules, immune cell function in the tumor microenvironment, antigen presentation, metabolism, and autophagy. Abnormalities or dysfunction of lysosomes are associated with the occurrence, development, and drug resistance of tumors. Lysosomes play a crucial role and have potential applications in tumor immunotherapy. Targeting lysosomes or harnessing their properties is an effective strategy for tumor immunotherapy. However, the mechanisms and approaches related to lysosomes in tumor immunotherapy are not fully understood at present, and further basic and clinical research is needed to provide better treatment options for cancer patients. This review focuses on the research progress related to lysosomes and tumor immunotherapy in these.
    Keywords:  immunotherapy; lysosomal autophagy; lysosomes; tumor immunity; tumor microenvironment
    DOI:  https://doi.org/10.3389/fimmu.2024.1308070
  46. Food Chem Toxicol. 2024 Feb 20. pii: S0278-6915(24)00104-2. [Epub ahead of print] 114538
    Arsenic disturbs neural tube closure involving AMPK/PKB-mTORC1-mediated autophagy in mice.
    Xiujuan Li, Gexuan Li, Shuo Cui, Yue Hou, Zelin Li, Ziyi Yan, Tingjuan Huang, Taoran Zhao, Hongkai Su, Bingrui Zhou, Juan Zhang, Ruifang Ao, Hong Zhao, Yulan Qiu, Zhizhen Liu, Jun Xie.
      Arsenic exposure is a significant risk factor for folate-resistant neural tube defects (NTDs), but the potential mechanism is unclear. In this study, a mouse model of arsenic-induced NTDs was established to investigate how arsenic affects early neurogenesis leading to malformations. The results showed that in utero exposure to arsenic caused a decline in the normal embryos, an elevated embryo resorption, and a higher incidence of malformed embryos. Cranial and spinal deformities were the main malformation phenotypes observed. Meanwhile, arsenic-induced NTDs were accompanied by an oxidant/antioxidant imbalance manifested by elevated levels of reactive oxygen species (ROS) and decreased antioxidant activities. In addition, changes in the expression of autophagy-related genes and proteins (ULK1, Atg5, LC3B, p62) as well as an increase in autophagosomes were observed in arsenic-induced aberrant brain vesicles. Also, the components of the upstream pathway regulating autophagy (AMPK, PKB, mTOR, Raptor) were altered accordingly after arsenic exposure. Collectively, our findings propose a mechanism for arsenic-induced NTDs involving AMPK/PKB-mTORC1-mediated autophagy. Blocking autophagic cell death due to excessive autophagy provides a novel strategy for the prevention of folate-resistant NTDs, especially for arsenic-exposed populations.
    Keywords:  AMPK/PKB-mTORC1; Arsenic; Autophagy; In utero exposure; Neural tube defects
    DOI:  https://doi.org/10.1016/j.fct.2024.114538
  47. Philos Trans R Soc Lond B Biol Sci. 2024 Apr 08. 379(1899): 20220372
    Understanding the endo-lysosomal network in neurodegeneration.
    Peter J Cullen, Henne Holstege, Scott A Small, Peter St George-Hyslop.
      
    Keywords:  Alzheimer's disease; Parkinson's disease; Retromer; endosomes; lysosomes; neurodegeneration
    DOI:  https://doi.org/10.1098/rstb.2022.0372
  48. Front Cell Dev Biol. 2024 ;12 1347857
    Role of autophagy in angiogenic potential of vascular pericytes.
    Soheil Zamen Milani, Aysa Rezabakhsh, Mohammad Karimipour, Leila Salimi, Narges Mardi, Maryam Taghavi Narmi, Fatemeh Sadeghsoltani, Ferzane Valioglu, Reza Rahbarghazi.
      The vasculature system is composed of a multiplicity of juxtaposed cells to generate a functional biological barrier between the blood and tissues. On the luminal surface of blood vessels, endothelial cells (ECs) are in close contact with circulating cells while supporting basal lamina and pericytes wrap the abluminal surface. Thus, the reciprocal interaction of pericytes with ECs is a vital element in the physiological activity of the vascular system. Several reports have indicated that the occurrence of pericyte dysfunction under ischemic and degenerative conditions results in varied micro and macro-vascular complications. Emerging evidence points to the fact that autophagy, a conserved self-digestive cell machinery, can regulate the activity of several cells like pericytes in response to various stresses and pathological conditions. Here, we aim to highlight the role of autophagic response in pericyte activity and angiogenesis potential following different pathological conditions.
    Keywords:  autophagy; pathological conditions; pericytes; protective/detrimental activity; vascular function
    DOI:  https://doi.org/10.3389/fcell.2024.1347857
  49. Nat Cell Biol. 2024 Feb 22.
    Drosophila TMEM63 and mouse TMEM63A are lysosomal mechanosensory ion channels.
    Kai Li, Yanmeng Guo, Yayu Wang, Ruijun Zhu, Wei Chen, Tong Cheng, Xiaofan Zhang, Yinjun Jia, Ting Liu, Wei Zhang, Lily Yeh Jan, Yuh Nung Jan.
      Cells sense physical forces and convert them into electrical or chemical signals, a process known as mechanotransduction. Whereas extensive studies focus on mechanotransduction at the plasma membrane, little is known about whether and how intracellular organelles sense mechanical force and the physiological functions of organellar mechanosensing. Here we identify the Drosophila TMEM63 (DmTMEM63) ion channel as an intrinsic mechanosensor of the lysosome, a major degradative organelle. Endogenous DmTMEM63 proteins localize to lysosomes, mediate lysosomal mechanosensitivity and modulate lysosomal morphology and function. Tmem63 mutant flies exhibit impaired lysosomal degradation, synaptic loss, progressive motor deficits and early death, with some of these mutant phenotypes recapitulating symptoms of TMEM63-associated human diseases. Importantly, mouse TMEM63A mediates lysosomal mechanosensitivity in Neuro-2a cells, indicative of functional conservation in mammals. Our findings reveal DmTMEM63 channel function in lysosomes and its physiological roles in vivo and provide a molecular basis to explore the mechanosensitive process in subcellular organelles.
    DOI:  https://doi.org/10.1038/s41556-024-01353-7
  50. Philos Trans R Soc Lond B Biol Sci. 2024 Apr 08. 379(1899): 20220389
    Differential effects of SORL1 deficiency on the endo-lysosomal network in human neurons and microglia.
    Swati Mishra, Suman Jayadev, Jessica E Young.
      The endosomal gene SORL1 is a strong Alzheimer's disease (AD) risk gene that harbours loss-of-function variants causative for developing AD. The SORL1 protein SORL1/SORLA is an endosomal receptor that interacts with the multi-protein sorting complex retromer to traffic various cargo through the endo-lysosomal network (ELN). Impairments in endo-lysosomal trafficking are an early cellular symptom in AD and a novel therapeutic target. However, the cell types of the central nervous system are diverse and use the ELN differently. If this pathway is to be effectively therapeutically targeted, understanding how key molecules in the ELN function in various cell types and how manipulating them affects cell-type specific responses relative to AD is essential. Here, we discuss an example where deficiency of SORL1 expression in a human model leads to stress on early endosomes and recycling endosomes in neurons, but preferentially leads to stress on lysosomes in microglia. The differences observed in these organelles could relate to the unique roles of these cells in the brain as neurons are professional secretory cells and microglia are professional phagocytic cells. Experiments to untangle these differences are fundamental to advancing the understanding of cell biology in AD and elucidating important pathways for therapeutic development. Human-induced pluripotent stem cell models are a valuable platform for such experiments. This article is part of a discussion meeting issue 'Understanding the endo-lysosomal network in neurodegeneration'.
    Keywords:  Alzheimer's disease; SORL1; endosomal trafficking; microglia; neurons
    DOI:  https://doi.org/10.1098/rstb.2022.0389
  51. Membranes (Basel). 2024 Feb 01. pii: 43. [Epub ahead of print]14(2):
    Membrane-Associated Ubiquitin Ligase RING Finger Protein 152 Orchestrates Melanogenesis via Tyrosinase Ubiquitination.
    Ryota Ueda, Rina Hashimoto, Yuki Fujii, José C J M D S Menezes, Hirotaka Takahashi, Hiroyuki Takeda, Tatsuya Sawasaki, Tomonori Motokawa, Kenzo Tokunaga, Hideaki Fujita.
      Lysosomal degradation of tyrosinase, a pivotal enzyme in melanin synthesis, negatively impacts melanogenesis in melanocytes. Nevertheless, the precise molecular mechanisms by which lysosomes target tyrosinase have remained elusive. Here, we identify RING (Really Interesting New Gene) finger protein 152 (RNF152) as a membrane-associated ubiquitin ligase specifically targeting tyrosinase for the first time, utilizing AlphaScreen technology. We observed that modulating RNF152 levels in B16 cells, either via overexpression or siRNA knockdown, resulted in decreased or increased levels of both tyrosinase and melanin, respectively. Notably, RNF152 and tyrosinase co-localized at the trans-Golgi network (TGN). However, upon treatment with lysosomal inhibitors, both proteins appeared in the lysosomes, indicating that tyrosinase undergoes RNF152-mediated lysosomal degradation. Through ubiquitination assays, we found the indispensable roles of both the RING and transmembrane (TM) domains of RNF152 in facilitating tyrosinase ubiquitination. In summary, our findings underscore RNF152 as a tyrosinase-specific ubiquitin ligase essential for regulating melanogenesis in melanocytes.
    Keywords:  RNF152; lysosome; melanogenesis; melanosome; tyrosinase; ubiquitin ligase
    DOI:  https://doi.org/10.3390/membranes14020043
  52. Leuk Res. 2024 Feb 12. pii: S0145-2126(24)00021-3. [Epub ahead of print]138 107455
    Bortezomib modulated the autophagy-lysosomal pathway in a TFEB-dependent manner in multiple myeloma.
    Rongjuan Zhang, Xinhong Yang, Xiaomin Shi, Enhong Xing, Lihong Wang, Changlai Hao, Zhihua Zhang.
       OBJECTIVE: To explore the involvement of TFEB-mediated autophagy-lysosomal mechanisms in multiple myeloma (MM) during bortezomib treatment.
    METHODS: MM cells were exposed to bortezomib or subjected to TFEB knockdown. CCK assay was used to assess the cell proliferation. Western blotting and fluorescent staining were conducted to examine autophagy and lysosomes. The TFEB expression pattern was analyzed, and whole transcriptome sequencing was carried out. Additionally, TFEB target genes were predicted using the GTRD(http://gtrd.biouml.org/) website, and pathway analysis was performed.
    RESULTS: Bortezomib demonstrated a dose-dependent and time dependent inhibition of cell proliferation. In MM cells treated with bortezomib, LC3B, Beclin-1, TFEB, and Lamp1 exhibited upregulation in a time- and concentration-dependent manner. LysoTracker dye labeling showed an increase in lysosomes in the bortezomib-treated group. Moreover, bortezomib elevated the expression of lysosome-associated factor Lamp1. Bortezomib promoted the nuclear translocation of TFEB, leading to decreased cytoplasmic TFEB and increased nuclear TFEB. TFEB gene silencing reversed bortezomib's inhibitory effect on MM cell lines, significantly reducing autophagosome expression and lysosome numbers. Furthermore, bioinformatic analysis identified the MAPK pathway as a potential downstream target of TFEB.
    CONCLUSION: Bortezomib effectively inhibits MM cell proliferation and induces autophagy, partly through TFEB-mediated mechanisms, with potential involvement of the MAPK pathway.
    Keywords:  Autophagy-lysosome; Bortezomib; Multiple myeloma; Transcription factor EB (TFEB) pathway
    DOI:  https://doi.org/10.1016/j.leukres.2024.107455
  53. J Dairy Sci. 2024 Feb 21. pii: S0022-0302(24)00506-X. [Epub ahead of print]
    Role of diacylglycerol O-acyltransferase 1 (DGAT1) in lipolysis and autophagy of adipose tissue from ketotic dairy cows.
    Qiushi Xu, Yunhui Fan, John Mauck, Juan J Loor, Xudong Sun, Hongdou Jia, Xinwei Li, Chuang Xu.
      High-yielding dairy cows in early lactation often encounter difficulties in meeting the energy requirements essential for maintaining milk production. This is primarily attributed to insufficient dry matter intake, which consequently leads to sustained lipolysis of adipose tissue. Fatty acids released by lipolysis can disrupt metabolic homeostasis. Autophagy, an adaptive response to intracellular environmental changes, is considered a crucial mechanism for regulating lipid metabolism and maintaining a proper cellular energy status. Despite its close relationship with aberrant lipid metabolism and cyto-lipotoxicity in animal models of metabolic disorders, the precise function of diacylglycerol o-acyltransferase 1 (DGAT1) in bovine adipose tissue during periods of negative energy balance (NEB) is not fully understood. Particularly regarding its involvement in lipolysis and autophagy. The objective of the present study was to assess the impact of DGAT1 on both lipolysis and autophagy in bovine adipose tissue and isolated adipocytes. Adipose tissue and blood samples were collected from cows diagnosed as clinically ketotic (n = 15) or healthy (n = 15) following a veterinary evaluation based on clinical symptoms and serum concentrations of BHB, which were 3.19 mM (interquartile range = 0.20) and 0.50 mM (interquartile range = 0.06), respectively. Protein abundance of DGAT1 and phosphorylation levels of unc-51-like kinase 1 (ULK1), were greater in adipose tissue from cows with ketosis, whereas phosphorylation levels of phosphoinositide 3-kinase (PI3K), protein kinase B (AKT), and mammalian target of rapamycin (mTOR) were lower. Furthermore, when adipocytes isolated from the harvested adipose tissue of 15 healthy cows were transfected with DGAT1 overexpression adenovirus or DGAT1 small interfering RNA followed by exposure to epinephrine (EPI), it led to greater ratios and protein abundance of phosphorylated hormone-sensitive triglyceride lipase (LIPE) to total LIPE and adipose triglyceride lipase (ATGL), while inhibiting the protein phosphorylation levels of ULK1, PI3K, AKT and mTOR. Overexpression of DGAT1 in EPI-treated adipocytes reduced lipolysis and autophagy, whereas silencing DGAT1 further exacerbated EPI-induced lipolysis and autophagy. Taken together, these findings indicate that upregulation of DGAT1 may function as an adaptive response to suppress adipocytes lipolysis, highlighting the significance of maintaining metabolic homeostasis in dairy cows during periods of NEB.
    Keywords:  DGAT1; autophagy; bovine adipocytes; lipolysis
    DOI:  https://doi.org/10.3168/jds.2023-24471
  54. Cell Death Discov. 2024 Feb 19. 10(1): 88
    Mechanism and role of mitophagy in the development of severe infection.
    Lixiu Ma, Tianyu Han, Yi-An Zhan.
      Mitochondria produce adenosine triphosphate and potentially contribute to proinflammatory responses and cell death. Mitophagy, as a conservative phenomenon, scavenges waste mitochondria and their components in the cell. Recent studies suggest that severe infections develop alongside mitochondrial dysfunction and mitophagy abnormalities. Restoring mitophagy protects against excessive inflammation and multiple organ failure in sepsis. Here, we review the normal mitophagy process, its interaction with invading microorganisms and the immune system, and summarize the mechanism of mitophagy dysfunction during severe infection. We highlight critical role of normal mitophagy in preventing severe infection.
    DOI:  https://doi.org/10.1038/s41420-024-01844-4
  55. Clin Immunol. 2024 Feb 19. pii: S1521-6616(24)00050-0. [Epub ahead of print] 109939
    Immmunometabolism of systemic lupus erythematosus.
    Marlene Marte Furment, Andras Perl.
      Systemic lupus erythematosus (SLE) is a potentially fatal chronic autoimmune disease which is underlain by complex dysfunction of the innate and adaptive immune systems. Although a series of well-defined genetic and environmental factors have been implicated in disease etiology, neither the development nor the persistence of SLE is well understood. Given that several disease susceptibility genes and environmental factors interact and influence inflammatory lineage specification through metabolism, the field of immunometabolism has become a forefront of cutting edge research. Along these lines, metabolic checkpoints of pathogenesis have been identified as targets of effective therapeutic interventions in mouse models and validated in clinical trials. Ongoing studies focus on mitochondrial oxidative stress, activation of the mechanistic target of rapamycin, calcium signaling, glucose utilization, tryptophan degradation, and metabolic cross-talk between gut microbiota and the host immune system.
    Keywords:  Adaptive immune system; Autoimmunity; Autophagy; Endosome traffic; Glucose; Glutathione; Immunometabolism; Innate immune system mitochondria; Kynurenine; Lysosome; Metabolism; Systemic lupus erythematosus; Tryptophan; mTOR
    DOI:  https://doi.org/10.1016/j.clim.2024.109939
  56. Biochem Biophys Res Commun. 2024 Feb 14. pii: S0006-291X(24)00224-9. [Epub ahead of print]704 149688
    Emodin activates autophagy to suppress oxidative stress and pyroptosis via mTOR-ULK1 signaling pathway and promotes multi-territory perforator flap survival.
    Panfeng Wu, Yu Xiao, Liming Qing, Yanan Mi, Juyu Tang, Zheming Cao, Chengxiong Huang.
       BACKGROUND: Multi-territory perforator flap reconstruction has been proven effective in treating large skin and soft tissue defects in clinical settings. However, in view of that the multi-territory perforator flap is prone to partial postoperative necrosis, increasing its survival is the key to the success of reconstruction. In this study, we aimed to clarify the effect of emodin on multi-territory perforator flap survival.
    METHODS: Flap survival was assessed by viability area analysis, infrared laser imaging detector, HE staining, immunohistochemistry, and angiography. Western blotting, immunofluorescence assays, and real-time fluorescent quantitative PCR were performed to detect the indicators of oxidative stress, pyroptosis and autophagy.
    RESULTS: After emodin treatment, the multi-territory perforator flap showed a significantly increased survival rate, which was shown to be closely related to the inhibition of oxidative stress and pyroptosis and enhanced autophagy. Meanwhile, the use of autophagy inhibitor 3 MA was found to reverse the inhibitory effects of emodin on oxidative stress and pyroptosis and weaken the improving effect of emodin on flap survival, suggesting that autophagy plays a critical role in emodin-treated flaps. Interestingly, our mechanistic investigations revealed that the positive effect of emodin on multi-territory perforator flap was attributed to the mTOR-ULK1 signaling pathway activation.
    CONCLUSIONS: Emodin can inhibit oxidative stress and pyroptosis by activating autophagy via the mTOR-ULK1 pathway, thereby improving the multi-territory perforator flap survival.
    Keywords:  Autophagy; Emodin; FUNDC1; Multi-territory perforator flap; Oxidative stress; Pyroptosis; mTOR-ULK1
    DOI:  https://doi.org/10.1016/j.bbrc.2024.149688
  57. bioRxiv. 2024 Feb 08. pii: 2024.02.06.579200. [Epub ahead of print]
    Inhibition of ULK1/2 and KRAS G12C controls tumor growth in preclinical models of lung cancer.
    Phaedra C Ghazi, Kayla T O'Toole, Sanjana Srinivas Boggaram, Michael T Scherzer, Mark R Silvis, Yun Zhang, Madhumita Bogdan, Bryan D Smith, Guillermina Lozano, Daniel L Flynn, Eric L Snyder, Conan G Kinsey, Martin McMahon.
      Mutational activation of KRAS occurs commonly in lung carcinogenesis and, with the recent FDA approval of covalent inhibitors of KRAS G12C such as sotorasib or adagrasib, KRAS oncoproteins are important pharmacological targets in non-small cell lung cancer (NSCLC). However, not all KRAS G12C -driven NSCLCs respond to these inhibitors, and the emergence of drug resistance in those patients that do respond can be rapid and pleiotropic. Hence, based on a backbone of covalent inhibition of KRAS G12C , efforts are underway to develop effective combination therapies. Here we report that inhibition of KRAS G12C signaling increases autophagy in KRAS G12C expressing lung cancer cells. Moreover, the combination of DCC-3116, a selective ULK1/2 inhibitor, plus sotorasib displays cooperative/synergistic suppression of human KRAS G12C -driven lung cancer cell proliferation in vitro and superior tumor control in vivo . Additionally, in genetically engineered mouse models of KRAS G12C -driven NSCLC, inhibition of either KRAS G12C or ULK1/2 decreases tumor burden and increases mouse survival. Consequently, these data suggest that ULK1/2-mediated autophagy is a pharmacologically actionable cytoprotective stress response to inhibition of KRAS G12C in lung cancer.
    DOI:  https://doi.org/10.1101/2024.02.06.579200
  58. Food Chem Toxicol. 2024 Feb 17. pii: S0278-6915(24)00088-7. [Epub ahead of print]186 114522
    Ginsenoside Rb1 alleviates 3-MCPD-induced renal cell pyroptosis by activating mitophagy.
    Ranran Zhang, Shuang Guan, Zhuoqun Meng, Duoduo Zhang, Jing Lu.
      Ginsenoside Rb1 (Gs-Rb1) is among the most significant effective pharmacological components in ginseng. 3-monochloropropane-1,2-diol (3-MCPD), a chloropropanol-like contaminant, is produced in the production of refined oils and thermal processing of food. Pyroptosis is a type of programmed cell death triggered by inflammasomes. Excessive pyroptosis causes kidney injury and inflammation. Previous studies have revealed that 3-MCPD induced pyroptosis in mice and NRK-52E cells. In the present study, we find that Gs-Rb1 attenuates 3-MCPD-induced renal cell pyroptosis by assaying GSDMD-N, caspase-1, IL-18, and IL-1β in mice and NRK-52E cells. In further mechanistic studies, we show that Gs-Rb1 removes damaged mitochondria via mitophagy and reduces intracellular reactive oxygen species (ROS) generation, therefore alleviating 3-MCPD-induced NOD-like receptor family pyrin domain containing 3 (NLRP3) activation and pyroptosis. The above results are further validated by the addition of autophagy inhibitor Chloroquine (CQ) and mitophagy inhibitor Cyclosporin A (CsA). Afterward, we explore how Gs-Rb1 activated mitophagy in vitro. We determine that Gs-Rb1 enhances the protein expression and nuclear translocation of Transcription factor EB (TFEB). However, silencing of the TFEB gene by small interfering RNA technology reverses the role of Gs-Rb1 in activating mitophagy. Therefore, we conclude that 3-MCPD damages mitochondria and leads to ROS accumulation, which causes NLRP3 activation and pyroptosis in ICR mice and NRK-52E cells, while Gs-Rb1 mitigates this phenomenon via the TFEB-mitophagy pathway. Our findings may provide new insights for understanding the molecular mechanisms by which Gs-Rb1 mitigates renal injury.
    Keywords:  3-monochloropropane-1,2-diol; Ginsenoside Rb1; Mitophagy; Pyroptosis; Renal injury; TFEB
    DOI:  https://doi.org/10.1016/j.fct.2024.114522
  59. Cell Commun Signal. 2024 Feb 19. 22(1): 134
    Dopamine enhances recovery after traumatic brain injury through ubiquitylation and autophagic degradation of RIPK1.
    Hui Luo, Ning Liu, Chao Lin.
       BACKGROUND: Although the neurotransmitter dopamine (DA) plays a crucial pathophysiologic role after traumatic brain injury (TBI), its function and specific underlying mechanisms of action remain unclear.
    METHODS: Adult male mice underwent controlled cortical impact (CCI). We administered DA intraperitoneally to mice for 14 consecutive days, starting 8 h before CCI. On day 3 after brain injury, cortical lesion volume and brain water content were measured. On days 7-13, behavioral tests were performed.
    RESULTS: Herein we report that DA inhibits neural death after injury, which is mediated via the dopamine D1 receptor (DRD1). Our results also showed that DRD1 signaling promotes RIPK1 ubiquitination via the E3 ubiquitin ligase Chip and then degradation through autophagy. Importantly, in vivo data revealed that DRD1 signaling prevented neural death, suppressed neuroinflammation, and restored many TBI-related functional sequelae.
    CONCLUSIONS: These data reveal a novel mechanism involving dopamine, and suggest that DRD1 activation positively regulates Chip-mediated ubiquitylation of RIPK1-leading to its autophagic degradation.
    Keywords:  Apoptosis; Autophagy; Chip; RIPK1; Traumatic brain injury
    DOI:  https://doi.org/10.1186/s12964-024-01515-y
  60. Biomed Pharmacother. 2024 Feb 22. pii: S0753-3322(24)00165-3. [Epub ahead of print]173 116284
    Autophagy regulation and redox perturbation by transcrocetin suppress the growth of endometriosis.
    Jiyeon Ham, Jisoo Song, Gwonhwa Song, Whasun Lim.
      Until non-hormonal therapeutic targets for endometriosis are suggested, we focused on mitochondrial function and autophagy regulation in the disease. Transcrocetin is a carotenoid and retinoic acid with high antioxidant potency and antiproliferative effects in several diseases. In this study, we demonstrated the therapeutic mechanisms of transcrocetin in endometriosis using the End1/E6E7 and VK2/E6E7 cell lines. Transcrocetin suppressed the viability and proliferation of these cell lines and did not affect the proliferation of normal uterine stromal cells. p21 Waf1/Cip1 as a cell cycle regulator and target of p53, were increased by transcrocetin and caused the G1 arrest via inhibition of cyclin-dependent kinase activity, which might further cause cell death. Furthermore, we confirmed endoplasmic reticulum stress and calcium ion dysregulation in the cytosol and mitochondrial matrix, disrupting the mitochondrial membrane potential. Mitochondrial bioenergetics were suppressed by transcrocetin, and oxidative phosphorylation-related gene expression was downregulated. Moreover, the proliferation of End1/E6E7 and VK2/E6E7 cells was regulated by transcrocetin-induced oxidative stress. Finally, we verified the impairment of autophagic flux following pre-treatment with chloroquine. Therefore, transcrocetin may be a potent therapeutic alternative for endometriosis.
    Keywords:  Autophagy; ER stress; Endometriosis; Mitochondria; Oxidative phosphorylation
    DOI:  https://doi.org/10.1016/j.biopha.2024.116284
  61. Medicine (Baltimore). 2024 Feb 23. 103(8): e37178
    Role of autophagy in skin photoaging: A narrative review.
    Xiaojiao Zhong, Ying Deng, Hongqiu Yang, Xiaoshuang Du, Ping Liu, Yu Du.
      As the largest organ of the human body, the skin serves as the primary barrier against external damage. The continuous increase in human activities and environmental pollution has resulted in the ongoing depletion of the ozone layer. Excessive exposure to ultraviolet (UV) radiation enhances the impact of external factors on the skin, leading to photoaging. Photoaging causes physical and psychological damage to the human body. The prevention and management of photoaging have attracted increased attention in recent years. Despite significant progress in understanding and mitigating UV-induced photoaging, the precise mechanisms through which autophagy contributes to the prevention of photoaging remain unclear. Given the important role of autophagy in repairing UV-induced DNA damage and scavenging oxidized lipids, autophagy is considered a novel strategy for preventing the occurrence of photoaging and other UV light-induced skin diseases. This review aims to elucidate the biochemical and clinical features of photoaging, the relationship of skin photoaging and chronological aging, the mechanisms underlying skin photoaging and autophagy, and the role of autophagy in skin photoaging.
    DOI:  https://doi.org/10.1097/MD.0000000000037178
  62. Philos Trans R Soc Lond B Biol Sci. 2024 Apr 08. 379(1899): 20220387
    Endo-lysosomal dysfunction in neurodegenerative diseases: opinion on current progress and future direction in the use of exosomes as biomarkers.
    Mathieu Herman, Grace W Randall, Julia L Spiegel, Delphina J Maldonado, Sabrina Simoes.
      Over the past two decades, increased research has highlighted the connection between endosomal trafficking defects and neurodegeneration. The endo-lysosomal network is an important, complex cellular system specialized in the transport of proteins, lipids, and other metabolites, essential for cell homeostasis. Disruption of this pathway is linked to a wide range of neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Huntington's disease and frontotemporal dementia. Furthermore, there is strong evidence that defects in this pathway create opportunities for diagnostic and therapeutic intervention. In this Opinion piece, we concisely address the role of endo-lysosomal dysfunction in five neurodegenerative diseases and discuss how future research can investigate this intracellular pathway, including extracellular vesicles with a specific focus on exosomes for the identification of novel disease biomarkers. This article is part of a discussion meeting issue 'Understanding the endo-lysosomal network in neurodegeneration'.
    Keywords:  biomarkers; endo-lysosomal dysfunction; endo-lysosomal system; exosomes; extracellular vesicles; neurodegenerative diseases
    DOI:  https://doi.org/10.1098/rstb.2022.0387
  63. Cell. 2024 Feb 09. pii: S0092-8674(24)00068-0. [Epub ahead of print]
    Mouse oocytes sequester aggregated proteins in degradative super-organelles.
    Gabriele Zaffagnini, Shiya Cheng, Marion C Salzer, Barbara Pernaute, Juan Manuel Duran, Manuel Irimia, Melina Schuh, Elvan Böke.
      Oocytes are among the longest-lived cells in the body and need to preserve their cytoplasm to support proper embryonic development. Protein aggregation is a major threat for intracellular homeostasis in long-lived cells. How oocytes cope with protein aggregation during their extended life is unknown. Here, we find that mouse oocytes accumulate protein aggregates in specialized compartments that we named endolysosomal vesicular assemblies (ELVAs). Combining live-cell imaging, electron microscopy, and proteomics, we found that ELVAs are non-membrane-bound compartments composed of endolysosomes, autophagosomes, and proteasomes held together by a protein matrix formed by RUFY1. Functional assays revealed that in immature oocytes, ELVAs sequester aggregated proteins, including TDP-43, and degrade them upon oocyte maturation. Inhibiting degradative activity in ELVAs leads to the accumulation of protein aggregates in the embryo and is detrimental for embryo survival. Thus, ELVAs represent a strategy to safeguard protein homeostasis in long-lived cells.
    Keywords:  RUFY1; embryo; female fertility; lysosomal acidification; membraneless organelles; oocyte; oocyte quality; protein aggregation; proteostasis; super-organelles
    DOI:  https://doi.org/10.1016/j.cell.2024.01.031
  64. Biomolecules. 2024 Jan 24. pii: 147. [Epub ahead of print]14(2):
    The HIF-1α and mTOR Pathways Amplify Heterotopic Ossification.
    Haitao Wang, Frederick S Kaplan, Robert J Pignolo.
      Fibrodysplasia ossificans progressiva (FOP; MIM# 135100) is an ultra-rare congenital disorder caused by gain-of-function point mutations in the Activin receptor A type I (ACVR1, also known as ALK2) gene. FOP is characterized by episodic heterotopic ossification (HO) in skeletal muscles, tendons, ligaments, or other soft tissues that progressively causes irreversible loss of mobility. FOP mutations cause mild ligand-independent constitutive activation as well as ligand-dependent bone morphogenetic protein (BMP) pathway hypersensitivity of mutant ACVR1. BMP signaling is also a key pathway for mediating acquired HO. However, HO is a highly complex biological process involving multiple interacting signaling pathways. Among them, the hypoxia-inducible factor (HIF) and mechanistic target of rapamycin (mTOR) pathways are intimately involved in both genetic and acquired HO formation. HIF-1α inhibition or mTOR inhibition reduces HO formation in mouse models of FOP or acquired HO in part by de-amplifying the BMP pathway signaling. Here, we review the recent progress on the mechanisms of the HIF-1α and mTOR pathways in the amplification of HO lesions and discuss the future directions and strategies to translate the targeting of HIF-1α and the mTOR pathways into clinical interventions for FOP and other forms of HO.
    Keywords:  fibrodysplasia ossificans progressiva; heterotopic ossification; hypoxia-inducible factor; mechanistic target of rapamycin (mTOR) pathways
    DOI:  https://doi.org/10.3390/biom14020147
  65. Sci Rep. 2024 02 18. 14(1): 4000
    Targeting autophagy as a therapeutic strategy in pediatric acute lymphoblastic leukemia.
    Henri Colyn Bwanika, Isabelle Rose Leo, Nona Struyf, Asimina Talanti, Luay Aswad, Aishwarya Konnur, Ann-Charlotte Björklund, Mats Heyman, Georgios Rassidakis, Tom Erkers, Brinton Seashore-Ludlow, Rozbeh Jafari, Katja Pokrovskaja Tamm.
      Autophagy is activated in response to a variety of stress conditions including anti-cancer therapies, and tumors cells often depend on autophagy for survival. In this study, we have evaluated inhibition of autophagy as therapeutic strategy in acute lymphoblastic leukemia (ALL) in children, both as a single treatment and in combination with glucocorticoid (GC) Dexamethasone (Dexa). Analysis of proteomics and RNA-seq of ALL cell lines and primary samples identified an upregulation of Vps34 and ATG14 proteins and autophagy and lysosomal pathway enrichment in a genetic subgroup with a recurrent t(12;21) translocation. Cells from this sugbroup were also significantly more sensitive to the selective autophagy or lysosomal inhibitors than cells with other genetic rearrangements. Further, combination of Dexa with either lysosomal or autophagy inhibitors was either synergistic or additive in killing leukemic cells across various genetic and lineage backgrounds, for both cell lines and primary samples, as assessed using viability assays and SynergyFinder as well as apoptotic caspase 3/7-based live-cell assays. Our data demonstrate that targeting autophagy represents a promising strategy for the treatment of pediatric ALL, both as a selective modality for the t(12;21) pre-B-ALL subgroup, and in combination treatments to sensitize to GC-induced cytotoxicity.
    DOI:  https://doi.org/10.1038/s41598-024-54400-6
  66. Exp Gerontol. 2024 Feb 18. pii: S0531-5565(24)00021-4. [Epub ahead of print] 112379
    The role of mitochondrial quality control mechanisms in chondrocyte senescence.
    Tianlei Zhao, Dawei Niu, Yancheng Chen, Peiliang Fu.
      Chondrocytes are the exclusive cellular constituents of articular cartilage, and their functional status governs the health of the cartilage. The primary factor contributing to the deterioration of cartilage structure and function is chondrocyte senescence. In hypoxia and hypodextrose environment, chondrocytes heavily rely on glycolysis for energy metabolism. Mitochondria, acting as the regulatory hub for chondrocyte energy metabolism, exhibit dysfunction before chondrocyte senescence, indicating their crucial involvement in the process. Previous research has suggested that molecules associated with mitochondrial quality control mechanisms can effectively restore mitochondrial function and alleviate chondrocyte senescence. However, there remains to be clarity regarding the relationship between mitochondrial quality control mechanisms and differences in efficacy among various target molecules, which pose challenges when evaluating them in chondrocytes. By conducting a comprehensive review of the existing literature on mitochondrial quality control mechanisms and chondrocyte senescence, we gain further insights into this intricate relationship while identifying promising targets that could potentially open up novel avenues for the treatment of chondrocyte senescence.
    Keywords:  Aging; Articular cartilage; Cellular senescence; Mitochondrial quality control; Osteoarthritis
    DOI:  https://doi.org/10.1016/j.exger.2024.112379
  67. bioRxiv. 2024 Feb 05. pii: 2023.10.04.560952. [Epub ahead of print]
    Impairment of the glial phagolysosomal system drives prion-like propagation in a Drosophila model of Huntington's disease.
    Graham H Davis, Aprem Zaya, Margaret M Panning Pearce.
      Protein misfolding, aggregation, and spread through the brain are primary drivers of neurodegenerative diseases pathogenesis. Phagocytic glia are responsible for regulating the load of pathogenic protein aggregates in the brain, but emerging evidence suggests that glia may also act as vectors for aggregate spread. Accumulation of protein aggregates could compromise the ability of glia to eliminate toxic materials from the brain by disrupting efficient degradation in the phagolysosomal system. A better understanding of phagocytic glial cell deficiencies in the disease state could help to identify novel therapeutic targets for multiple neurological disorders. Here, we report that mutant huntingtin (mHTT) aggregates impair glial responsiveness to injury and capacity to degrade neuronal debris in male and female adult Drosophila expressing the gene that causes Huntington's disease (HD). mHTT aggregate formation in neurons impairs engulfment and clearance of injured axons and causes accumulation of phagolysosomes in glia. Neuronal mHTT expression induces upregulation of key innate immunity and phagocytic genes, some of which were found to regulate mHTT aggregate burden in the brain. Finally, a forward genetic screen revealed Rab10 as a novel component of Draper-dependent phagocytosis that regulates mHTT aggregate transmission from neurons to glia. These data suggest that glial phagocytic defects enable engulfed mHTT aggregates to evade lysosomal degradation and acquire prion-like characteristics. Together, our findings reveal new mechanisms that enhance our understanding of the beneficial and potentially harmful effects of phagocytic glia in HD and potentially other neurodegenerative diseases.
    SIGNIFICANCE STATEMENT: Deposition of amyloid aggregates is strongly associated with neurodegenerative disease progression and neuronal cell loss. Many studies point to glial cells as dynamic mediators of disease, capable of phagocytosing toxic materials, but also promoting chronic inflammation and proteopathic aggregate spread. Thus, glia have emerged as promising therapeutic targets for disease intervention. Here, we demonstrate in a Drosophila model of Huntington's disease that neuronal mHTT aggregates interfere with glial phagocytic engulfment, phagolysosomal processing, and innate immunity transcriptional responses. We also identify Rab10 as a novel modifier of prion-like transmission of mHTT aggregates. Our findings add to a growing narrative of glia as double-edged players in neurodegenerative diseases.
    DOI:  https://doi.org/10.1101/2023.10.04.560952
  68. Int J Mol Sci. 2024 Feb 06. pii: 1950. [Epub ahead of print]25(4):
    Carnosic Acid against Lung Cancer: Induction of Autophagy and Activation of Sestrin-2/LKB1/AMPK Signalling.
    Eric J O'Neill, Newman Siu Kwan Sze, Rebecca E K MacPherson, Evangelia Tsiani.
      Non-small cell lung cancer (NSCLC) represents 80% of all lung cancer cases and is characterized by low survival rates due to chemotherapy and radiation resistance. Novel treatment strategies for NSCLC are urgently needed. Liver kinase B1 (LKB1), a tumor suppressor prevalently mutated in NSCLC, activates AMP-activated protein kinase (AMPK) which in turn inhibits mammalian target of rapamycin complex 1 (mTORC1) and activates unc-51 like autophagy activating kinase 1 (ULK1) to promote autophagy. Sestrin-2 is a stress-induced protein that enhances LKB1-dependent activation of AMPK, functioning as a tumor suppressor in NSCLC. In previous studies, rosemary (Rosmarinus officinalis) extract (RE) activated the AMPK pathway while inhibiting mTORC1 to suppress proliferation, survival, and migration, leading to the apoptosis of NSCLC cells. In the present study, we investigated the anticancer potential of carnosic acid (CA), a bioactive polyphenolic diterpene compound found in RE. The treatment of H1299 and H460 NSCLC cells with CA resulted in concentration and time-dependent inhibition of cell proliferation assessed with crystal violet staining and 3H-thymidine incorporation, and concentration-dependent inhibition of survival, assessed using a colony formation assay. Additionally, CA induced apoptosis of H1299 cells as indicated by decreased B-cell lymphoma 2 (Bcl-2) levels, increased cleaved caspase-3, -7, poly (ADP-ribose) polymerase (PARP), Bcl-2-associated X protein (BAX) levels, and increased nuclear condensation. These antiproliferative and proapoptotic effects coincided with the upregulation of sestrin-2 and the phosphorylation/activation of LKB1 and AMPK. Downstream of AMPK signaling, CA increased levels of autophagy marker light chain 3 (LC3), an established marker of autophagy; inhibiting autophagy with 3-methyladenine (3MA) blocked the antiproliferative effect of CA. Overall, these data indicate that CA can inhibit NSCLC cell viability and that the underlying mechanism of action of CA involves the induction of autophagy through a Sestrin-2/LKB1/AMPK signaling cascade. Future experiments will use siRNA and small molecule inhibitors to better elucidate the role of these signaling molecules in the mechanism of action of CA as well as tumor xenograft models to assess the anticancer properties of CA in vivo.
    Keywords:  AMPK; LKB1; NSCLC; apoptosis; autophagy; carnosic acid; lung cancer; polyphenols; sestrin-2
    DOI:  https://doi.org/10.3390/ijms25041950
  69. Cell Death Discov. 2024 Feb 22. 10(1): 93
    Thioredoxin-1 decreases alpha-synuclein induced by MPTP through promoting autophagy-lysosome pathway.
    Rou Gu, Liping Bai, Fang Yan, Se Zhang, Xianwen Zhang, Ruhua Deng, Xiansi Zeng, Bo Sun, Xiaomei Hu, Ye Li, Jie Bai.
      Parkinson's disease (PD) is characterized by the formation of Lewy body in dopaminergic neurons in the substantia nigra pars compacta (SNpc). Alpha-synuclein (α-syn) is a major component of Lewy body. Autophagy eliminates damaged organelles and abnormal aggregated proteins. Thioredoxin-1 (Trx-1) is a redox regulating protein and plays roles in protecting dopaminergic neurons against neurotoxicity induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). However, the relationship between Trx-1 and α-syn in PD is still unknown. In the present study, the movement disorder and dopaminergic neurotoxicity in MPTP-treated mice were improved by Trx-1 overexpression and were aggravated by Trx-1 knockdown in the SNpc in mice. The expression of α-syn was increased in the SNpc of MPTP-treated mice, which was inhibited by Trx-1 overexpression and was exacerbated in Trx-1 knockdown mice. Autophagosomes was increased under electron microscope after MPTP treatment, which were recovered in Trx-1 overexpressing mice and were further increased in Trx-1 knockdown in the SNpc in mice. The expressions of phosphatase and tensin homolog deleted on chromosome ten (PTEN)-induced putative kinase 1 (PINK1), Parkin, LC3 II and p62 were increased by MPTP, which were blocked in Trx-1 overexpressing mice and were further increased in Trx-1 knockdown mice. Cathepsin D was decreased by MPTP, which was restored in Trx-1 overexpressing mice and was further decreased in Trx-1 knockdown mice. The mRFP-GFP-LC3 green fluorescent dots were increased by 1-methyl-4-phenylpyridinium (MPP+) and further increased in Trx-1 siRNA transfected PC12 cells, while mRFP-GFP-LC3 red fluorescent dots were increased in Trx-1 overexpressing cells. These results indicate that Trx-1 may eliminate α-syn in PD mice through potentiating autophagy-lysosome pathway.
    DOI:  https://doi.org/10.1038/s41420-024-01848-0
  70. PLoS One. 2024 ;19(2): e0298095
    The PINK1/Parkin pathway of mitophagy exerts a protective effect during prion disease.
    Anne Ward, Forrest Jessop, Robert Faris, Jason Hollister, Daniel Shoup, Brent Race, Catharine M Bosio, Suzette A Priola.
      The PINK1/Parkin pathway of mitophagy has been implicated in the pathogenesis of Parkinson's disease. In prion diseases, a transmissible neurodegenerative disease caused by the misfolded and infectious prion protein (PrPSc), expression of both PINK1 and Parkin are elevated, suggesting that PINK1/Parkin mediated mitophagy may also play a role in prion pathogenesis. Using mice in which expression of either PINK1 (PINK1KO) or Parkin (ParkinKO) has been ablated, we analyzed the potential role of PINK1 and Parkin in prion pathogenesis. Prion infected PINK1KO and ParkinKO mice succumbed to disease more rapidly (153 and 150 days, respectively) than wild-type control C57Bl/6 mice (161 days). Faster incubation times in PINK1KO and ParkinKO mice did not correlate with altered prion pathology in the brain, altered expression of proteins associated with mitochondrial dynamics, or prion-related changes in mitochondrial respiration. However, the expression level of mitochondrial respiration Complex I, a major site for the formation of reactive oxygen species (ROS), was higher in prion infected PINK1KO and ParkinKO mice when compared to prion infected control mice. Our results demonstrate a protective role for PINK1/Parkin mitophagy during prion disease, likely by helping to minimize ROS formation via Complex I, leading to slower prion disease progression.
    DOI:  https://doi.org/10.1371/journal.pone.0298095
  71. Nat Cell Biol. 2024 Feb 22.
    Lysosomal channels sensing forces.
    Erika Riederer, Dejian Ren.
      
    DOI:  https://doi.org/10.1038/s41556-024-01347-5
  72. Cells. 2024 Feb 06. pii: 296. [Epub ahead of print]13(4):
    Pathogenesis of DJ-1/PARK7-Mediated Parkinson's Disease.
    Line Duborg Skou, Steffi Krudt Johansen, Justyna Okarmus, Morten Meyer.
      Parkinson's disease (PD) is a common movement disorder associated with the degeneration of dopaminergic neurons in the substantia nigra pars compacta. Mutations in the PD-associated gene PARK7 alter the structure and function of the encoded protein DJ-1, and the resulting autosomal recessively inherited disease increases the risk of developing PD. DJ-1 was first discovered in 1997 as an oncogene and was associated with early-onset PD in 2003. Mutations in DJ-1 account for approximately 1% of all recessively inherited early-onset PD occurrences, and the functions of the protein have been studied extensively. In healthy subjects, DJ-1 acts as an antioxidant and oxidative stress sensor in several neuroprotective mechanisms. It is also involved in mitochondrial homeostasis, regulation of apoptosis, chaperone-mediated autophagy (CMA), and dopamine homeostasis by regulating various signaling pathways, transcription factors, and molecular chaperone functions. While DJ-1 protects neurons against damaging reactive oxygen species, neurotoxins, and mutant α-synuclein, mutations in the protein may lead to inefficient neuroprotection and the progression of PD. As current therapies treat only the symptoms of PD, the development of therapies that directly inhibit oxidative stress-induced neuronal cell death is critical. DJ-1 has been proposed as a potential therapeutic target, while oxidized DJ-1 could operate as a biomarker for PD. In this paper, we review the role of DJ-1 in the pathogenesis of PD by highlighting some of its key neuroprotective functions and the consequences of its dysfunction.
    Keywords:  DJ-1; PARK7; Parkinson’s disease; mitochondria; neuroprotection; neurotoxicity; oxidative stress; reactive oxygen species
    DOI:  https://doi.org/10.3390/cells13040296
  73. Nat Commun. 2024 Feb 20. 15(1): 1531
    Genome-wide screens identify SEL1L as an intracellular rheostat controlling collagen turnover.
    Michael J Podolsky, Benjamin Kheyfets, Monika Pandey, Afaq H Beigh, Christopher D Yang, Carlos O Lizama, Ritwik Datta, Liangguang L Lin, Zhihong Wang, Paul J Wolters, Michael T McManus, Ling Qi, Kamran Atabai.
      Accumulating evidence has implicated impaired extracellular matrix (ECM) clearance as a key factor in fibrotic disease. Despite decades of research elucidating the effectors of ECM clearance, relatively little is understood regarding the upstream regulation of this process. Collagen is the most abundant constituent of normal and fibrotic ECM in mammalian tissues. Its catabolism occurs through extracellular proteolysis and cell-mediated uptake of collagen fragments for intracellular degradation. Given the paucity of information regarding the regulation of this latter process, here we execute unbiased genome-wide screens to understand the molecular underpinnings of cell-mediated collagen clearance. Using this approach, we discover a mechanism through which collagen biosynthesis is sensed by cells internally and directly regulates clearance of extracellular collagen. The sensing mechanism appears to be dependent on endoplasmic reticulum-resident protein SEL1L and occurs via a noncanonical function of this protein. This pathway functions as a homeostatic negative feedback loop that limits collagen accumulation in tissues. In human fibrotic lung disease, the induction of this collagen clearance pathway by collagen synthesis is impaired, thereby contributing to the pathological accumulation of collagen in lung tissue. Thus, we describe cell-autonomous, rheostatic collagen clearance as an important pathway of tissue homeostasis.
    DOI:  https://doi.org/10.1038/s41467-024-45817-8
  74. Front Physiol. 2024 ;15 1344951
    Mitochondrial quality control alterations and placenta-related disorders.
    Yamei Wu, Meng Li, Hao Ying, Ying Gu, Yunlong Zhu, Yanfang Gu, Lu Huang.
      Mitochondria are ubiquitous in eukaryotic cells. Normal maintenance of function is the premise and basis for various physiological activities. Mitochondrial dysfunction is commonly observed in a wide range of pathological conditions, such as neurodegenerative, metabolic, cardiovascular, and various diseases related to foetal growth and development. The placenta is a highly energy-dependent organ that acts as an intermediary between the mother and foetus and functions to maintain foetal growth and development. Recent studies have demonstrated that mitochondrial dysfunction is associated with placental disorders. Defects in mitochondrial quality control mechanisms may lead to preeclampsia and foetal growth restriction. In this review, we address the quality control mechanisms of mitochondria and the relevant pathologies of mitochondrial dysfunction in placenta-related diseases, such as preeclampsia and foetal growth restriction. This review also investigates the relation between mitochondrial dysfunction and placental disorders.
    Keywords:  foetal growth restriction; mitochondria; mitochondrial dysfunction; placenta; preeclampsia
    DOI:  https://doi.org/10.3389/fphys.2024.1344951
  75. Endocrine. 2024 Feb 22.
    SQSTM1/p62 is a prognostic molecular marker and potential therapeutic target for pancreatic neuroendocrine tumours.
    Yu-Li Song, Jun-Hua Weng, Da-Chun Zhao, Jia-Lei Zhang, Yuan-Jia Chen, Bao-Hong Xu.
       BACKGROUND: There have been few studies on the role of autophagy in pancreatic neuroendocrine tumours (PNETs). SQSTM1/p62 (also called Sequestosome 1) is a potential autophagy regulator, and its biological roles and clinical significance in PNETs remain poorly understood.
    PURPOSE: The purpose of this study was to evaluate the clinical significance of SQSTM1/p62 in human PNET specimens and to evaluate its potential value as a therapeutic target by studying its biological function in PNET cell lines.
    METHODS: SQSTM1/p62 protein expression was assessed in 106 PNET patient specimens by immunohistochemistry, and the relationship between SQSTM1/p62 protein expression and the clinicopathological features of PNETs in patients was analysed. The proliferation, invasion and apoptosis of SQSTM1/p62-knockdown QGP-1 and INS-1 cells were assessed by the MTT assay, a Transwell assay and flow cytometry. Cell autophagy was assessed by western blotting and mCherry-GFP-LC3B.
    RESULTS: The protein expression of SQSTM1/p62 in PNET patient specimens was significantly correlated with tumour recurrence (p = 0.005) and worse prognosis (log rank p = 0.020). Downregulation of the SQSTM1/p62 gene inhibited tumour cell proliferation and migration and induced PNET cell death. Downregulation of SQSTM1/p62 activated autophagy in PNET cell lines but blocked autophagic flow. Knockdown of the SQSTM1/p62 gene inhibited mTOR phosphorylation.
    CONCLUSION: The SQSTM1/P62 protein could be an independent prognostic marker for PNET patients. Downregulating SQSTM1/P62 can inhibit PNET progression, inhibit mTOR phosphorylation and block autophagic flow.
    Keywords:  Autophagy; Pancreatic neuroendocrine tumours; Prognosis; SQSTM1/p62; mTOR phosphorylation
    DOI:  https://doi.org/10.1007/s12020-023-03546-w
  76. Proc Natl Acad Sci U S A. 2024 Feb 27. 121(9): e2318046121
    Mechanism and cellular function of direct membrane binding by the ESCRT and ERES-associated Ca2+-sensor ALG-2.
    Sankalp Shukla, Wei Chen, Shanlin Rao, Serim Yang, Chenxi Ou, Kevin P Larsen, Gerhard Hummer, Phyllis I Hanson, James H Hurley.
      Apoptosis linked Gene-2 (ALG-2) is a multifunctional intracellular Ca2+ sensor and the archetypal member of the penta-EF hand protein family. ALG-2 functions in the repair of damage to both the plasma and lysosome membranes and in COPII-dependent budding at endoplasmic reticulum exit sites (ERES). In the presence of Ca2+, ALG-2 binds to ESCRT-I and ALIX in membrane repair and to SEC31A at ERES. ALG-2 also binds directly to acidic membranes in the presence of Ca2+ by a combination of electrostatic and hydrophobic interactions. By combining giant unilamellar vesicle-based experiments and molecular dynamics simulations, we show that charge-reversed mutants of ALG-2 at these locations disrupt membrane recruitment. ALG-2 membrane binding mutants have reduced or abrogated ERES localization in response to Thapsigargin-induced Ca2+ release but still localize to lysosomes following lysosomal Ca2+ release. In vitro reconstitution shows that the ALG-2 membrane-binding defect can be rescued by binding to ESCRT-I. These data thus reveal the nature of direct Ca2+-dependent membrane binding and its interplay with Ca2+-dependent protein binding in the cellular functions of ALG-2.
    Keywords:  ESCRT; calcium-binding protein; lysosome; membrane repair; reconstitution
    DOI:  https://doi.org/10.1073/pnas.2318046121
  77. Oncol Lett. 2024 Apr;27(4): 140
    Rapamycin inhibits B16 melanoma cell viability invitro and invivo by inducing autophagy and inhibiting the mTOR/p70‑S6k pathway.
    Penghui Wang, Haifang Zhang, Kaikai Guo, Chun Liu, Shimin Chen, Baopeng Pu, Sirun Chen, Tong Feng, Hanyi Jiao, Chang Gao.
      Rapamycin is an immunosuppressant that has been shown to prevent tumor growth following organ transplantation. However, its exact mode of antitumor action remains unknown. The present study used the B16-F10 (B16) murine melanoma model to explore the antitumor mechanism of rapamycin, and it was revealed that rapamycin reduced B16 cell viability in vitro and in vivo. In addition, in vitro and in vivo, the results of western blotting showed that rapamycin reduced Bcl2 expression, and enhanced the protein expression levels of cleaved caspase 3 and Bax, indicating that it can induce the apoptosis of B16 melanoma cells. Furthermore, the results of cell cycle analysis and western blotting showed that rapamycin induced B16 cell cycle arrest in the G1 phase, based on the reduction in the protein expression levels of CDK1, cyclin D1 and CDK4, as well as the increase in the percentage of cells in G1 phase. Rapamycin also significantly increased the number of autophagosomes in B16 melanoma cells, as determined by transmission electron microscopy. Furthermore, the results of RT-qPCR and western blotting showed that rapamycin upregulated the protein expression levels of microtubule-associated protein light chain 3 (LC3) and Beclin-1, while downregulating the expression of p62 in vitro and in vivo, thus indicating that rapamycin could trigger cellular autophagy. The present study revealed that rapamycin in combination with chloroquine (CQ) further increased LC3 expression compared with that in the CQ group, suggesting that rapamycin induced an increase in autophagy in B16 cells. Furthermore, the results of western blotting showed that rapamycin blocked the phosphorylation of p70 ribosomal S6 kinase (p70-S6k) and mammalian target of rapamycin (mTOR) proteins in vitro and in vivo, thus suggesting that rapamycin may exert its antitumor effect by inhibiting the phosphorylation of the mTOR/p70-S6k pathway. In conclusion, rapamycin may inhibit tumor growth by inducing cellular G1 phase arrest and apoptosis. In addition, rapamycin may exert its antitumor effects by inducing the autophagy of B16 melanoma cells in vitro and in vivo, and the mTOR/p70-S6k signaling pathway may be involved in this process.
    Keywords:  B16 melanoma cells; apoptosis; autophagy; cell cycle; mTOR/p70-S6k signaling pathway; rapamycin
    DOI:  https://doi.org/10.3892/ol.2024.14273
  78. Dev Cell. 2024 Feb 14. pii: S1534-5807(24)00046-7. [Epub ahead of print]
    ATG5 attenuates inflammatory signaling in mouse embryonic stem cells to control differentiation.
    Sheng Li, Jin Sun, Bo-Wen Zhang, Lu Yang, Ying-Cui Wan, Bei-Bei Chen, Nan Xu, Qian-Ru Xu, Juan Fan, Jia-Ni Shang, Rui Li, Chen-Ge Yu, Yan Xi, Su Chen.
      Attenuated inflammatory response is a property of embryonic stem cells (ESCs). However, the underlying mechanisms are unclear. Moreover, whether the attenuated inflammatory status is involved in ESC differentiation is also unknown. Here, we found that autophagy-related protein ATG5 is essential for both attenuated inflammatory response and differentiation of mouse ESCs and that attenuation of inflammatory signaling is required for mouse ESC differentiation. Mechanistically, ATG5 recruits FBXW7 to promote ubiquitination and proteasome-mediated degradation of β-TrCP1, resulting in the inhibition of nuclear factor κB (NF-κB) signaling and inflammatory response. Moreover, differentiation defects observed in ATG5-depleted mouse ESCs are due to β-TrCP1 accumulation and hyperactivation of NF-κB signaling, as loss of β-TrCP1 and inhibition of NF-κB signaling rescued the differentiation defects. Therefore, this study reveals a previously uncharacterized mechanism maintaining the attenuated inflammatory response in mouse ESCs and further expands the understanding of the biological roles of ATG5.
    Keywords:  ATG5; FBXW7; NF-κB signaling; embryonic stem cells; inflammatory response; β-TrCP1
    DOI:  https://doi.org/10.1016/j.devcel.2024.01.026
  79. Acta Neuropathol Commun. 2024 Feb 23. 12(1): 32
    Stimulating VAPB-PTPIP51 ER-mitochondria tethering corrects FTD/ALS mutant TDP43 linked Ca2+ and synaptic defects.
    Andrea Markovinovic, Sandra M Martín-Guerrero, Gábor M Mórotz, Shaakir Salam, Patricia Gomez-Suaga, Sebastien Paillusson, Jenny Greig, Younbok Lee, Jacqueline C Mitchell, Wendy Noble, Christopher C J Miller.
      Frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS) are clinically linked major neurodegenerative diseases. Notably, TAR DNA-binding protein-43 (TDP43) accumulations are hallmark pathologies of FTD/ALS and mutations in the gene encoding TDP43 cause familial FTD/ALS. There are no cures for FTD/ALS. FTD/ALS display damage to a broad range of physiological functions, many of which are regulated by signaling between the endoplasmic reticulum (ER) and mitochondria. This signaling is mediated by the VAPB-PTPIP51 tethering proteins that serve to recruit regions of ER to the mitochondrial surface so as to facilitate inter-organelle communications. Several studies have now shown that disrupted ER-mitochondria signaling including breaking of the VAPB-PTPIP51 tethers are features of FTD/ALS and that for TDP43 and other familial genetic FTD/ALS insults, this involves activation of glycogen kinase-3β (GSK3β). Such findings have prompted suggestions that correcting damage to ER-mitochondria signaling and the VAPB-PTPIP51 interaction may be broadly therapeutic. Here we provide evidence to support this notion. We show that overexpression of VAPB or PTPIP51 to enhance ER-mitochondria signaling corrects mutant TDP43 induced damage to inositol 1,4,5-trisphosphate (IP3) receptor delivery of Ca2+ to mitochondria which is a primary function of the VAPB-PTPIP51 tethers, and to synaptic function. Moreover, we show that ursodeoxycholic acid (UDCA), an FDA approved drug linked to FTD/ALS and other neurodegenerative diseases therapy and whose precise therapeutic target is unclear, corrects TDP43 linked damage to the VAPB-PTPIP51 interaction. We also show that this effect involves inhibition of TDP43 mediated activation of GSK3β. Thus, correcting damage to the VAPB-PTPIP51 tethers may have therapeutic value for FTD/ALS and other age-related neurodegenerative diseases.
    Keywords:  Alzheimer’s disease; Amyotrophic lateral sclerosis; Frontotemporal dementia; Neurodegenerative diseases; Parkinson’s disease; TDP43
    DOI:  https://doi.org/10.1186/s40478-024-01742-x
  80. Dev Cell. 2024 Feb 16. pii: S1534-5807(24)00036-4. [Epub ahead of print]
    A metabolically controlled contact site between vacuoles and lipid droplets in yeast.
    Duy Trong Vien Diep, Javier Collado, Marie Hugenroth, Rebecca Martina Fausten, Louis Percifull, Mike Wälte, Christian Schuberth, Oliver Schmidt, Rubén Fernández-Busnadiego, Maria Bohnert.
      The lipid droplet (LD) organization proteins Ldo16 and Ldo45 affect multiple aspects of LD biology in yeast. They are linked to the LD biogenesis machinery seipin, and their loss causes defects in LD positioning, protein targeting, and breakdown. However, their molecular roles remained enigmatic. Here, we report that Ldo16/45 form a tether complex with Vac8 to create vacuole lipid droplet (vCLIP) contact sites, which can form in the absence of seipin. The phosphatidylinositol transfer protein (PITP) Pdr16 is a further vCLIP-resident recruited specifically by Ldo45. While only an LD subpopulation is engaged in vCLIPs at glucose-replete conditions, nutrient deprivation results in vCLIP expansion, and vCLIP defects impair lipophagy upon prolonged starvation. In summary, Ldo16/45 are multifunctional proteins that control the formation of a metabolically regulated contact site. Our studies suggest a link between LD biogenesis and breakdown and contribute to a deeper understanding of how lipid homeostasis is maintained during metabolic challenges.
    Keywords:  LDAF1; Ldb16; Ldo16; Ldo45; Pdr16; Sei1; Vac8; lipophagy; promethin; seipin
    DOI:  https://doi.org/10.1016/j.devcel.2024.01.016
  81. Cell Prolif. 2024 Feb 23. e13621
    Ferritinophagy: A novel insight into the double-edged sword in ferritinophagy-ferroptosis axis and human diseases.
    Jing-Yan Li, Yan-Hua Feng, Yu-Xuan Li, Peng-Yi He, Qi-Yuan Zhou, Ying-Ping Tian, Ren-Qi Yao, Yong-Ming Yao.
      Nuclear receptor coactive 4 (NCOA4), which functions as a selective cargo receptor, is a critical regulator of the particularly autophagic degradation of ferritin, a process known as ferritinophagy. Mechanistically, NCOA4-mediated ferritinophagy performs an increasingly vital role in the maintenance of intracellular iron homeostasis by promoting ferritin transport and iron release as needed. Ferritinophagy is not only involved in iron-dependent responses but also in the pathogenesis and progression of various human diseases, including metabolism-related, neurodegenerative, cardiovascular and infectious diseases. Therefore, ferritinophagy is of great importance in maintaining cell viability and function and represents a potential therapeutic target. Recent studies indicated that ferritinophagy regulates the signalling pathway associated with ferroptosis, a newly discovered type of cell death characterised by iron-dependent lipid peroxidation. Although accumulating evidence clearly demonstrates the importance of the interplay between dysfunction in iron metabolism and ferroptosis, a deeper understanding of the double-edged sword effect of ferritinophagy in ferroptosis has remained elusive. Details of the mechanisms underlying the ferritinophagy-ferroptosis axis in regulating relevant human diseases remain to be elucidated. In this review, we discuss the latest research findings regarding the mechanisms that regulate the biological function of NCOA4-mediated ferritinophagy and its contribution to the pathophysiology of ferroptosis. The important role of the ferritinophagy-ferroptosis axis in human diseases will be discussed in detail, highlighting the great potential of targeting ferritinophagy in the treatment of diseases.
    DOI:  https://doi.org/10.1111/cpr.13621
  82. Arch Biochem Biophys. 2024 Feb 21. pii: S0003-9861(24)00064-X. [Epub ahead of print] 109945
    Activation of adenosine A2B receptor alleviates myocardial ischemia-reperfusion injury by inhibiting endoplasmic reticulum stress and restoring autophagy flux.
    Feng He, Fuyu Wang, Hanmin Xiang, Yunna Ma, Qing Lu, Yun Xia, Huimin Zhou, Yanlin Wang, Jianjuan Ke.
      Myocardial ischemia-reperfusion injury (MIRI) poses a significant threat to patients with coronary heart disease. Adenosine A2A receptors have been known as a protective role in MIRI by regulating autophagy, so we assumed that activation of adenosine A2B receptor (A2BAR) might exert a similar effect during MIRI and underlying mechanism be related to proteostasis maintenance as well. In situ hearts were subjected to 30 min of ischemia and 120 min of reperfusion (IR), while in vitro cardiomyocytes from neonatal rats experienced 6 h of oxygen-glucose deprivation followed by 12 h of reoxygenation (OGDR). Initially, we observed that post-ischemia-reperfusion induced autophagy flux blockade and ERS both in vivo and in vitro, evident through the increased expression of p62, LC3Ⅱ, and BIP, which indicated the deteriorated proteostasis. We used a selective A2BAR agonist, Bay 60-6583, to explore the positive effects of A2BAR on cardiomyocytes and found that A2BAR activation rescued damaged cardiac function and morphological changes in the IR group and improved frail cell viability in the OGDR group. The A2BAR agonist also alleviated the blockage of autophagic flux, coupled with augmented ERS in the IR/OGDR group, which was reassured by using an autophagy inhibitor chloroquine (CQ) and ERS inhibitor (4-PBA) in vitro. Additionally, considering cAMP/PKA as a well-known downstream effector of A2BAR, we utilized H89, a selective PKA inhibitor. We observed that the positive efficacy of Bay 60-6583 was inhibited by H89. Collectively, our findings demonstrate that the A2BAR/cAMP/PKA signaling pathway exerts a protective role in MIRI by mitigating impaired autophagic flux and excessive ERS.
    Keywords:  Adenosine receptor; Autophagy flux; Endoplasmic reticulum stress; PKA
    DOI:  https://doi.org/10.1016/j.abb.2024.109945
  83. Antioxidants (Basel). 2024 Jan 31. pii: 183. [Epub ahead of print]13(2):
    Bone Marrow Mesenchymal Stem Cell-Derived Exosomes Ameliorate Aging-Induced BTB Impairment in Porcine Testes by Activating Autophagy and Inhibiting ROS/NLRP3 Inflammasomes via the AMPK/mTOR Signaling Pathway.
    Yi Zhou, Jiale Yan, Limin Qiao, Jiaqin Zeng, Fuyu Cao, Xihui Sheng, Xiaolong Qi, Cheng Long, Bingying Liu, Xiangguo Wang, Hua Yao, Longfei Xiao.
      As a pivotal player in spermatogenesis, the blood-testis barrier (BTB) made from junction apparatus coexisting in Sertoli cells (SCs) is impaired with an increase in age and ultimately induces spermatogenic dysfunction or even infertility. It has been corroborated that bone marrow mesenchymal stem cell (BMSC) transplantation can efficiently repair and regenerate the testicular function. As vital mediators of cell-to-cell communication, MSC-derived exosomes (Exos) can directly serve as therapeutic agents for tissue repair and regeneration. However, the therapeutic value of BMSC-Exos in aging-induced BTB damage remains to be confirmed. In this study, we explored that the old porcine testes had defective autophagy, which aggravated BTB disruption in SCs. BMSC-Exos could decrease ROS production and NLRP3 inflammasome activation but enhanced autophagy and tight junction (TJ) function in D-gal-triggered aging porcine SCs and mouse model testes, according to in vitro and in vivo experiments. Furthermore, rapamycin, NAC, MCC950, and IL-1Ra restored the TJ function in D-gal-stimulated aging porcine SCs, while BMSC-Exos' stimulatory effect on TJ function was inhibited by chloroquine. Moreover, the treatment with BMSC-Exos enhanced autophagy in D-gal-induced aging porcine SCs by means of the AMPK/mTOR signal transduction pathway. These findings uncovered through the present study that BMSC-Exos can enhance the BTB function in aging testes by improving autophagy via the AMPK/mTOR signaling pathway, thereby suppressing ROS production and NLRP3 inflammasome activation.
    Keywords:  BMSC-Exos; autophagy; blood-testis barrier; senescence; tight junction
    DOI:  https://doi.org/10.3390/antiox13020183
  84. bioRxiv. 2024 Feb 09. pii: 2023.02.09.527915. [Epub ahead of print]
    Enhanced Branched-Chain Amino Acid Metabolism Improves Age-Related Reproduction in C. elegans.
    Chen Lesnik, Rachel Kaletsky, Jasmine M Ashraf, Salman Sohrabi, Vanessa Cota, Titas Sengupta, William Keyes, Shijing Luo, Coleen T Murphy.
      Reproductive aging is one of the earliest human aging phenotypes, and mitochondrial dysfunction has been linked to oocyte quality decline. However, it is not known which mitochondrial metabolic processes are critical for oocyte quality maintenance with age. To understand how mitochondrial processes contribute to C. elegans oocyte quality, we characterized the mitochondrial proteomes of young and aged wild-type and long-reproductive daf-2 mutants. Here we show that the mitochondrial proteomic profiles of young wild-type and daf-2 worms are similar and share upregulation of branched-chain amino acid (BCAA) metabolism pathway enzymes. Reduction of the BCAA catabolism enzyme BCAT-1 shortens reproduction, elevates mitochondrial reactive oxygen species levels, and shifts mitochondrial localization. Moreover, bcat-1 knockdown decreases oocyte quality in daf-2 worms and reduces reproductive capability, indicating the role of this pathway in the maintenance of oocyte quality with age. Importantly, oocyte quality deterioration can be delayed, and reproduction can be extended in wild-type animals both by bcat-1 overexpression and by supplementing with Vitamin B1, a cofactor needed for BCAA metabolism.
    DOI:  https://doi.org/10.1101/2023.02.09.527915
  85. Trends Cell Biol. 2024 Feb 22. pii: S0962-8924(24)00023-0. [Epub ahead of print]
    ER remodeling via lipid metabolism.
    Wonyul Jang, Volker Haucke.
      Unlike most other organelles found in multiple copies, the endoplasmic reticulum (ER) is a unique singular organelle within eukaryotic cells. Despite its continuous membrane structure, encompassing more than half of the cellular endomembrane system, the ER is subdivided into specialized sub-compartments, including morphological, membrane contact site (MCS), and de novo organelle biogenesis domains. In this review, we discuss recent emerging evidence indicating that, in response to nutrient stress, cells undergo a reorganization of these sub-compartmental ER domains through two main mechanisms: non-destructive remodeling of morphological ER domains via regulation of MCS and organelle hitchhiking, and destructive remodeling of specialized domains by ER-phagy. We further highlight and propose a critical role of membrane lipid metabolism in this ER remodeling during starvation.
    Keywords:  endoplasmic reticulum; hitchhiking; lipids; membrane contact sites; membrane remodeling; metabolism; nutrient stress
    DOI:  https://doi.org/10.1016/j.tcb.2024.01.011
  86. Nat Commun. 2024 Feb 20. 15(1): 1541
    A mutational atlas for Parkin proteostasis.
    Lene Clausen, Vasileios Voutsinos, Matteo Cagiada, Kristoffer E Johansson, Martin Grønbæk-Thygesen, Snehal Nariya, Rachel L Powell, Magnus K N Have, Vibe H Oestergaard, Amelie Stein, Douglas M Fowler, Kresten Lindorff-Larsen, Rasmus Hartmann-Petersen.
      Proteostasis can be disturbed by mutations affecting folding and stability of the encoded protein. An example is the ubiquitin ligase Parkin, where gene variants result in autosomal recessive Parkinsonism. To uncover the pathological mechanism and provide comprehensive genotype-phenotype information, variant abundance by massively parallel sequencing (VAMP-seq) is leveraged to quantify the abundance of Parkin variants in cultured human cells. The resulting mutational map, covering 9219 out of the 9300 possible single-site amino acid substitutions and nonsense Parkin variants, shows that most low abundance variants are proteasome targets and are located within the structured domains of the protein. Half of the known disease-linked variants are found at low abundance. Systematic mapping of degradation signals (degrons) reveals an exposed degron region proximal to the so-called "activation element". This work provides examples of how missense variants may cause degradation either via destabilization of the native protein, or by introducing local signals for degradation.
    DOI:  https://doi.org/10.1038/s41467-024-45829-4
  87. J Cancer Res Ther. 2023 Oct 01. 19(7): 1931-1938
    A free fatty acid receptor agonist inducing autophagy in HT-29 cells by downregulating the AKT/mTOR signaling pathway.
    Elham Hoveizi, Behnoosh Rafienia, Ali Shahriari.
       AIMS: GW9508, a free fatty acid receptor agonist acts in a G-coupled protein receptor 40 (GPR40)-dependent pathway. Here, we investigated the induction of stress oxidative and autophagy by GW9508 in the human colorectal cancer cell line (HT-29) and the crosstalk between autophagy and apoptotic in HT-29 cells.
    METHODS: HT-29 was treated with GW9508 at a concentrations range of 50-500 μM in fibrin gel. Cell viability was investigated using an MTT assay. Induction of autophagy and apoptosis was assessed through Western blotting for associated proteins, acridine orange staining, MDC staining, qRT-PCR, and electron microscopy. Also, we estimated the molecular interactions between GW9805 and some markers through molecular docking.
    RESULTS: GW9508 inhibited HT-29 cell proliferation, induced apoptosis, and resulted in autophagy. The induced autophagy in cells was confirmed by the observation of autophagosomes, the presence of autophagy markers, including beclin-1, LC3, AMPK, and lack expression of mTOR and AKT. Moreover, GW9508 treatment significantly increased the expression of catalase and superoxide dismutase in cells.
    DISCUSSION: Our results indicated that GW9508 could induce autophagy by inhibiting the Akt/mTOR in HT-29. Hence, GW9508 is suggested as a novel anticancer reagent.
    DOI:  https://doi.org/10.4103/jcrt.jcrt_1184_21
  88. Cell Death Differ. 2024 Feb 23.
    Exposure of the inner mitochondrial membrane triggers apoptotic mitophagy.
    Tahnee L Saunders, Simon P Windley, Gediminas Gervinskas, Katherine R Balka, Caitlin Rowe, Rachael Lane, Maximilien Tailler, Thanh Ngoc Nguyen, Georg Ramm, Michael Lazarou, Dominic De Nardo, Benjamin T Kile, Kate McArthur.
      During apoptosis mediated by the intrinsic pathway, BAX/BAK triggers mitochondrial permeabilization and the release of cytochrome-c, followed by a dramatic remodelling of the mitochondrial network that results in mitochondrial herniation and the subsequent release of pro-inflammatory mitochondrial components. Here, we show that mitochondrial herniation and subsequent exposure of the inner mitochondrial membrane (IMM) to the cytoplasm, initiates a unique form of mitophagy to deliver these damaged organelles to lysosomes. IMM-induced mitophagy occurs independently of canonical PINK1/Parkin signalling and is driven by ubiquitination of the IMM. Our data suggest IMM-induced mitophagy is an additional safety mechanism that cells can deploy to contain damaged mitochondria. It may have particular relevance in situations where caspase activation is incomplete or inhibited, and in contexts where PINK1/Parkin-mitophagy is impaired or overwhelmed.
    DOI:  https://doi.org/10.1038/s41418-024-01260-2
  89. Nature. 2024 Feb 21.
    Targeted protein degradation via intramolecular bivalent glues.
    Oliver Hsia, Matthias Hinterndorfer, Angus D Cowan, Kentaro Iso, Tasuku Ishida, Ramasubramanian Sundaramoorthy, Mark A Nakasone, Hana Imrichova, Caroline Schätz, Andrea Rukavina, Koraljka Husnjak, Martin Wegner, Alejandro Correa-Sáez, Conner Craigon, Ryan Casement, Chiara Maniaci, Andrea Testa, Manuel Kaulich, Ivan Dikic, Georg E Winter, Alessio Ciulli.
      Targeted protein degradation is a pharmacological modality that is based on the induced proximity of an E3 ubiquitin ligase and a target protein to promote target ubiquitination and proteasomal degradation. This has been achieved either via proteolysis-targeting chimeras (PROTACs)-bifunctional compounds composed of two separate moieties that individually bind the target and E3 ligase, or via molecular glues that monovalently bind either the ligase or the target1-4. Here, using orthogonal genetic screening, biophysical characterization and structural reconstitution, we investigate the mechanism of action of bifunctional degraders of BRD2 and BRD4, termed intramolecular bivalent glues (IBGs), and find that instead of connecting target and ligase in trans as PROTACs do, they simultaneously engage and connect two adjacent domains of the target protein in cis. This conformational change 'glues' BRD4 to the E3 ligases DCAF11 or DCAF16, leveraging intrinsic target-ligase affinities that do not translate to BRD4 degradation in the absence of compound. Structural insights into the ternary BRD4-IBG1-DCAF16 complex guided the rational design of improved degraders of low picomolar potency. We thus introduce a new modality in targeted protein degradation, which works by bridging protein domains in cis to enhance surface complementarity with E3 ligases for productive ubiquitination and degradation.
    DOI:  https://doi.org/10.1038/s41586-024-07089-6
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