bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2024–08–25
75 papers selected by
Viktor Korolchuk, Newcastle University
  1. Rag-Ragulator is the central organizer of the physical architecture of the mTORC1 nutrient-sensing pathway.
  2. Artificial targeting of autophagy components to mitochondria reveals both conventional and unconventional mitophagy pathways.
  3. Nutrient Sensing of mTORC1 signaling in cancer and aging.
  4. BIN1 deficiency enhances ULK3-dependent autophagic flux and reduces dendritic size in mouse hippocampal neurons.
  5. Palmitoylation of ULK1 by ZDHHC13 plays a crucial role in autophagy.
  6. TRPML1 ameliorates seizures-related neuronal injury by regulating autophagy and lysosomal biogenesis via Ca2+/TFEB signaling pathway.
  7. Myotubularin 2 interacts with SEC23A and negatively regulates autophagy at ER exit sites in arabidopsis.
  8. The Estrogen Receptor-Related Orphan Receptors (ERRs) Regulate Autophagy through TFEB.
  9. Dual roles of AtNBR1 in regulating selective autophagy via liquid-liquid phase separation and recognition of non-ubiquitinated substrates in Arabidopsis.
  10. Mitochondrial bioenergetics stimulates autophagy for pathological MAPT/Tau clearance in tauopathy neurons.
  11. WIPI2b recruitment to phagophores and ATG16L1 binding are regulated by ULK1 phosphorylation.
  12. Nucleophagy in Aspergillus oryzae is Mediated by Autophagosome Formation and Vacuole-Mediated Degradation.
  13. TRIM44 enhances autophagy via SQSTM1 oligomerization in response to oxidative stress.
  14. O-GlcNAc impacts mitophagy via the PINK1-dependent pathway.
  15. The paradox of autophagy in cancer: NEAT1's role in tumorigenesis and therapeutic resistance.
  16. Usp14 down-regulation corrects sleep and circadian dysfunction of a Drosophila model of Parkinson's disease.
  17. Mapping autophagy-related membrane contact site proteins and complexes with AutoMCS Navigator.
  18. Targeting Autophagy: A Promising Therapeutic Strategy for Diabetes Mellitus and Diabetic Nephropathy.
  19. Inhibitors of the mTOR signaling pathway can play an important role in breast cancer immunopathogenesis.
  20. FOXO3 Activates MFN2 Expression to Maintain the Autophagy Response in Cancer Cells Under Amino Acid Deprivation.
  21. Lysosomal biogenesis and function in osteoclasts: a comprehensive review.
  22. An old dog with new tricks: TFEB promotes syncytin expression and cell fusion in the human placenta.
  23. Rejuvenation of BMSCs senescence by pharmacological enhancement of TFEB-mediated autophagy alleviates aged-related bone loss and extends lifespan in middle aged mice.
  24. Targeting spinal mechanistic target of rapamycin complex 2 alleviates inflammatory and neuropathic pain.
  25. The pivotal role of dysregulated autophagy in the progression of non-alcoholic fatty liver disease.
  26. Ac-HSP20 regulates autophagy and promotes the encystation of Acanthamoeba castellanii by inhibiting the PI3K/AKT/mTOR signaling pathway.
  27. Non-canonical metabolic and molecular effects of calorie restriction are revealed by varying temporal conditions.
  28. FTO-mediated m 6A demethylation of ULK1 mRNA promotes autophagy and activation of hepatic stellate cells in liver fibrosis.
  29. The autophagy proteome in the brain.
  30. Contactin -Associated protein1 Regulates Autophagy by Modulating the PI3K/AKT/mTOR Signaling Pathway and ATG4B Levels in Vitro and in Vivo.
  31. GABARAP interacts with EGFR - supporting the unique role of this hAtg8 protein during receptor trafficking.
  32. Strigolactones positively regulate HY5-dependent autophagy and the degradation of ubiquitinated proteins in response to cold stress in tomato.
  33. Diagnosing X-Linked Myopathy With Excessive Autophagy After 30 years: Genetic, Ultrasonographic, and Electrodiagnostic Findings.
  34. Myocardial ischemia-reperfusion injury: The balance mechanism between mitophagy and NLRP3 inflammasome.
  35. Structural basis for lipid transfer by the ATG2A-ATG9A complex.
  36. Tailoring the pKa of Fluorescence Lifetime Imaging Probes to Visualize Aggrephagy and Resolve Its Microenvironmental Viscosity.
  37. TFEB controls expression of human syncytins during cell-cell fusion.
  38. Npc1 deficiency impairs microglia function via TREM2-mTOR signaling in Niemann-Pick disease type C.
  39. NLRP3 and autophagy in retinal ganglion cell inflammation in age-related macular degeneration: potential therapeutic implications.
  40. Inhibition of OLR1 reduces SASP of nucleus pulposus cells by targeting autophagy-GATA4 axis.
  41. Ferulic acid restores mitochondrial dynamics and autophagy via AMPK signaling pathway in a palmitate-induced hepatocyte model of metabolic syndrome.
  42. Disrupted mitochondrial response to nutrients is a presymptomatic event in the cortex of the APPSAA knock-in mouse model of Alzheimer's disease.
  43. Bibliometric analysis of lipophagy:2013 to 2023.
  44. OTULIN's influence on neuroinflammation and pain modulation in trigeminal neuralgia.
  45. Pediatric cancer-pathology and microenvironment influence: a perspective into osteosarcoma and non-osteogenic mesenchymal malignant neoplasms.
  46. Mitochondrial protein deacetylation by SIRT3 in osteoclasts promotes bone resorption with aging in female mice.
  47. Lysosomes drive the piecemeal removal of mitochondrial inner membrane.
  48. Early treatment with 2-deoxy-d-glucose reduces proliferative proteins in the kidney and slows cyst growth in a hypomorphic Pkd1 mouse model of autosomal dominant polycystic kidney disease (PKD).
  49. Knocking down EGR1 inhibits nucleus pulposus cell senescence and mitochondrial damage through activation of PINK1-Parkin dependent mitophagy, thereby delaying intervertebral disc degeneration.
  50. Mechanical stress-induced autophagy is cytoskeleton dependent.
  51. MiR-302c-3p regulates autophagy and apoptosis in ovarian granulosa cells via the LATS2/YAP axis in chickens.
  52. Hesperetin regulates PI3K/Akt and mTOR pathways to exhibit its antiproliferative effect against colon cancer cells.
  53. Navigating the labyrinth of long non-coding RNAs in colorectal cancer: From chemoresistance to autophagy.
  54. Notch signaling promotes differentiation, cell death and autophagy in Drosophila hematopoietic system.
  55. Isobavachin induces autophagy-mediated cytotoxicity in AML12 cells via AMPK and PI3K/Akt/mTOR pathways.
  56. Iron-sulfur cluster loss in mitochondrial CISD1 mediates PINK1 loss-of-function phenotypes.
  57. PTBP1 knockdown impairs autophagy flux and inhibits gastric cancer progression through TXNIP-mediated oxidative stress.
  58. Spatial Activation of Autophagy in Human Placenta-Related Tissue During Labor: A Possible Mechanism for Labor Onset.
  59. Dihydromyricetin improves high glucose induced dopaminergic neuronal damage by activating AMPK-autophagy signaling pathway.
  60. Aloperine Suppresses Cancer Progression by Interacting with VPS4A to Inhibit Autophagosome-lysosome Fusion in NSCLC.
  61. FOXO4 suppresses cisplatin resistance of Triple-Negative Breast Cancer by inhibiting autophagy.
  62. Mitochondria-Specific Fluorescent Probe for Revealing the Interaction between Mitochondria and Lysosomes during Apoptosis.
  63. Accumulation of damaged mitochondria in aging astrocytes due to mitophagy dysfunction: Implications for susceptibility to mitochondrial stress.
  64. Proteolysis-targeting drug delivery system (ProDDS): integrating targeted protein degradation concepts into formulation design.
  65. An "Iron-phagy" nanoparticle inducing irreversible mitochondrial damages for antitumor therapy.
  66. Twisted Intramolecular Charge Transfer-Based Viscosity-Responsive Probe Reveals Lysosomal Degradation Process of Endocytosed Foreign Bodies.
  67. The Rubicon-WIPI axis regulates exosome biogenesis during ageing.
  68. Protocol for quantifying LC3B FRET biosensor activity in living cells using a broad-to-sensitive data analysis pipeline.
  69. FAM210A: An emerging regulator of mitochondrial homeostasis.
  70. Anti-ageing interventions for the treatment of cardiovascular disease.
  71. The prion-like effect and prion-like protein targeting strategy in amyotrophic lateral sclerosis.
  72. The autophagy-targeting compound V46 enhances antimicrobial responses to Mycobacteroides abscessus by activating transcription factor EB.
  73. Short-term post-fast refeeding enhances intestinal stemness via polyamines.
  74. TRIM21-mediated ubiquitination of SQSTM1/p62 abolishes its Ser403 phosphorylation and enhances palmitic acid cytotoxicity.
  75. The microbiota-dependent tryptophan metabolite alleviates high-fat diet-induced insulin resistance through the hepatic AhR/TSC2/mTORC1 axis.
  1. Proc Natl Acad Sci U S A. 2024 Aug 27. 121(35): e2322755121
    Rag-Ragulator is the central organizer of the physical architecture of the mTORC1 nutrient-sensing pathway.
    Max L Valenstein, Pranav V Lalgudi, Xin Gu, Jibril F Kedir, Martin S Taylor, Raghu R Chivukula, David M Sabatini.
      The mechanistic target of rapamycin complex 1 (mTORC1) pathway regulates cell growth and metabolism in response to many environmental cues, including nutrients. Amino acids signal to mTORC1 by modulating the guanine nucleotide loading states of the heterodimeric Rag GTPases, which bind and recruit mTORC1 to the lysosomal surface, its site of activation. The Rag GTPases are tethered to the lysosome by the Ragulator complex and regulated by the GATOR1, GATOR2, and KICSTOR multiprotein complexes that localize to the lysosomal surface through an unknown mechanism(s). Here, we show that mTORC1 is completely insensitive to amino acids in cells lacking the Rag GTPases or the Ragulator component p18. Moreover, not only are the Rag GTPases and Ragulator required for amino acids to regulate mTORC1, they are also essential for the lysosomal recruitment of the GATOR1, GATOR2, and KICSTOR complexes, which stably associate and traffic to the lysosome as the "GATOR" supercomplex. The nucleotide state of RagA/B controls the lysosomal association of GATOR, in a fashion competitively antagonized by the N terminus of the amino acid transporter SLC38A9. Targeting of Ragulator to the surface of mitochondria is sufficient to relocalize the Rags and GATOR to this organelle, but not to enable the nutrient-regulated recruitment of mTORC1 to mitochondria. Thus, our results reveal that the Rag-Ragulator complex is the central organizer of the physical architecture of the mTORC1 nutrient-sensing pathway and underscore that mTORC1 activation requires signal transduction on the lysosomal surface.
    Keywords:  biochemistry; mTOR signaling; nutrient sensing
    DOI:  https://doi.org/10.1073/pnas.2322755121
  2. Autophagy. 2024 Aug 23.
    Artificial targeting of autophagy components to mitochondria reveals both conventional and unconventional mitophagy pathways.
    Katharina C Lorentzen, Alan R Prescott, Ian G Ganley.
      Macroautophagy/autophagy enables lysosomal degradation of a diverse array of intracellular material. This process is essential for normal cellular function and its dysregulation is implicated in many diseases. Given this, there is much interest in understanding autophagic mechanisms of action in order to determine how it can be best targeted therapeutically. In mitophagy, the selective degradation of mitochondria via autophagy, mitochondria first need to be primed with signals that allow the recruitment of the core autophagy machinery to drive the local formation of an autophagosome around the target mitochondrion. To determine how the recruitment of different core autophagy components can drive mitophagy, we took advantage of the mito-QC mitophagy assay (an outer mitochondrial membrane-localized tandem mCherry-GFP tag). By tagging autophagy proteins with an anti-mCherry (or anti-GFP) nanobody, we could recruit them to mitochondria and simultaneously monitor levels of mitophagy. We found that targeting ULK1, ATG16L1 and the different Atg8-family proteins was sufficient to induce mitophagy. Mitochondrial recruitment of ULK1 and the Atg8-family proteins induced a conventional mitophagy pathway, requiring RB1CC1/FIP200, PIK3C3/VPS34 activity and ATG5. Surprisingly, the mitophagy pathway upon recruitment of ATG16L1 proceeded independently of ATG5, although it still required RB1CC1 and PIK3C3/VPS34 activity. In this latter pathway, mitochondria were alternatively delivered to lysosomes via uptake into early endosomes.
    Keywords:  ATG16L1; Atg8; ULK1; nanobody; targeted organelle degradation
    DOI:  https://doi.org/10.1080/15548627.2024.2395149
  3. Semin Cancer Biol. 2024 Aug 14. pii: S1044-579X(24)00059-2. [Epub ahead of print]
    Nutrient Sensing of mTORC1 signaling in cancer and aging.
    Cong Jiang, Xiao Tan, Ning Liu, Peiqiang Yan, Tao Hou, Wenyi Wei.
      The mechanistic target of rapamycin complex 1 (mTORC1) is indispensable for preserving cellular and organismal homeostasis by balancing the anabolic and catabolic processes in response to various environmental cues, such as nutrients, growth factors, energy status, oxygen levels, and stress. Dysregulation of mTORC1 signaling is associated with the progression of many types of human disorders including cancer, age-related diseases, neurodegenerative disorders, and metabolic diseases. The way mTORC1 senses various upstream signals and converts them into specific downstream responses remains a crucial question with significant impacts for our perception of the related physiological and pathological process. In this review, we discuss the recent molecular and functional insights into the nutrient sensing of the mTORC1 signaling pathway, along with the emerging role of deregulating nutrient-mTORC1 signaling in cancer and age-related disorders.
    Keywords:  amino acid; kinase; mTOR; mTORC1; mTORC2; nutrient sensing; phosphorylation; tumorigenesis
    DOI:  https://doi.org/10.1016/j.semcancer.2024.08.001
  4. Autophagy. 2024 Aug 22.
    BIN1 deficiency enhances ULK3-dependent autophagic flux and reduces dendritic size in mouse hippocampal neurons.
    Yuxi Jin, Lin Zhao, Yanli Zhang, Tingzhen Chen, Huili Shi, Huaiqing Sun, Shixin Ding, Sijia Chen, Haifeng Cao, Guannan Zhang, Qian Li, Junying Gao, Ming Xiao, Chengyu Sheng.
      Genome-wide association studies identified variants around the BIN1 (bridging integrator 1) gene locus as prominent risk factors for late-onset Alzheimer disease. In the present study, we decreased the expression of BIN1 in mouse hippocampal neurons to investigate its neuronal function. Bin1 knockdown via RNAi reduced the dendritic arbor size in primary cultured hippocampal neurons as well as in mature Cornu Ammonis 1 excitatory neurons. The AAV-mediated Bin1 RNAi knockdown also generated a significant regional volume loss around the injection sites at the organ level, as revealed by 7-Tesla structural magnetic resonance imaging, and an impaired spatial reference memory performance in the Barnes maze test. Unexpectedly, Bin1 knockdown led to concurrent activation of both macroautophagy/autophagy and MTOR (mechanistic target of rapamycin kinase) complex 1 (MTORC1). Autophagy inhibition with the lysosome inhibitor chloroquine effectively mitigated the Bin1 knockdown-induced dendritic regression. The subsequent molecular study demonstrated that increased expression of ULK3 (unc-51 like kinase 3), which is MTOR-insensitive, supported autophagosome formation in BIN1 deficiency. Reducing ULK3 activity with SU6668, a receptor tyrosine kinase inhibitor, or decreasing neuronal ULK3 expression through AAV-mediated RNAi, significantly attenuated Bin1 knockdown-induced hippocampal volume loss and spatial memory decline. In Alzheimer disease patients, the major neuronal isoform of BIN1 is specifically reduced. Our work suggests this reduction is probably an important molecular event that increases the autophagy level, which might subsequently promote brain atrophy and cognitive impairment through reducing dendritic structures, and ULK3 is a potential interventional target for relieving these detrimental effects.
    Keywords:  Alzheimer disease; BIN1; ULK3; autophagy; hippocampal atrophy
    DOI:  https://doi.org/10.1080/15548627.2024.2393932
  5. Nat Commun. 2024 Aug 21. 15(1): 7194
    Palmitoylation of ULK1 by ZDHHC13 plays a crucial role in autophagy.
    Keisuke Tabata, Kenta Imai, Koki Fukuda, Kentaro Yamamoto, Hayato Kunugi, Toshiharu Fujita, Tatsuya Kaminishi, Christian Tischer, Beate Neumann, Sabine Reither, Fatima Verissimo, Rainer Pepperkok, Tamotsu Yoshimori, Maho Hamasaki.
      Autophagy is a highly conserved process from yeast to mammals in which intracellular materials are engulfed by a double-membrane organelle called autophagosome and degrading materials by fusing with the lysosome. The process of autophagy is regulated by sequential recruitment and function of autophagy-related (Atg) proteins. Genetic hierarchical analyses show that the ULK1 complex comprised of ULK1-FIP200-ATG13-ATG101 translocating from the cytosol to autophagosome formation sites as a most upstream ATG factor; this translocation is critical in autophagy initiation. However, how this translocation occurs remains unclear. Here, we show that ULK1 is palmitoylated by palmitoyltransferase ZDHHC13 and translocated to the autophagosome formation site upon autophagy induction. We find that the ULK1 palmitoylation is required for autophagy initiation. Moreover, the ULK1 palmitoylated enhances the phosphorylation of ATG14L, which is required for activating PI3-Kinase and producing phosphatidylinositol 3-phosphate, one of the autophagosome membrane's lipids. Our results reveal how the most upstream ULK1 complex translocates to the autophagosome formation sites during autophagy.
    DOI:  https://doi.org/10.1038/s41467-024-51402-w
  6. Biochim Biophys Acta Mol Basis Dis. 2024 Aug 22. pii: S0925-4439(24)00471-X. [Epub ahead of print]1870(8): 167477
    TRPML1 ameliorates seizures-related neuronal injury by regulating autophagy and lysosomal biogenesis via Ca2+/TFEB signaling pathway.
    Tingting Peng, Yinyin Xie, Senfeng Zhao, Xiaoyi Wang, Wanwan Zhang, Yi Xie, Cui Wang, Nanchang Xie.
      Alterations in autophagy have been observed in epilepsy, although their exact etiopathogenesis remains elusive. Transient Receptor Potential Mucolipin Protein 1 (TRPML1) is an ion channel protein that regulates autophagy and lysosome biogenesis. To explore the role of TRPML1 in seizures-induced neuronal injury and the potential mechanisms involved, an hyperexcitable neuronal model induced by Mg2+-free solution was used for the study. Our results revealed that TRPML1 expression was upregulated after seizures, which was accompanied by intracellular ROS accumulation, mitochondrial damage, and neuronal apoptosis. Activation of TRPML1 by ML-SA1 diminished intracellular ROS, restored mitochondrial function, and subsequently alleviated neuronal apoptosis. Conversely, inhibition of TRPML1 had the opposite effect. Further examination revealed that the accumulation of ROS and damaged mitochondria was associated with interrupted mitophagy flux and enlarged defective lysosomes, which were attenuated by TRPML1 activation. Mechanistically, TRPML1 activation allows more Ca2+ to permeate from the lysosome into the cytoplasm, resulting in the dephosphorylation of TFEB and its nuclear translocation. This process further enhances autophagy initiation and lysosomal biogenesis. Additionally, the expression of TRPML1 is positively regulated by WTAP-mediated m6A modification. Our findings highlighted crucial roles of TRPML1 and autophagy in seizures-induced neuronal injury, which provides a new target for epilepsy treatment.
    Keywords:  Autophagy; Epilepsy; Lysosome; TFEB; TRPML1
    DOI:  https://doi.org/10.1016/j.bbadis.2024.167477
  7. Autophagy. 2024 Aug 23.
    Myotubularin 2 interacts with SEC23A and negatively regulates autophagy at ER exit sites in arabidopsis.
    Xinjing Li, Jing Zheng, Jing Su, Lin Wang, Lin Luan, Taotao Wang, Fang Bai, Qing Zhong, Qingqiu Gong.
      Starvation- or stress-induced phosphatidylinositol 3-phosphate (PtdIns3P/PI3P) production at the endoplasmic reticulum (ER) subdomains organizes phagophore assembly and autophagosome formation. Coat protein complex II (COPII) vesicles budding from ER exit site (ERES) also contribute to autophagosome formation. Whether any PtdIns3P phosphatase functions at ERES to inhibit macroautophagy/autophagy is unknown. Here we report Myotubularin 2 (MTM2) of Arabidopsis as a PtdIns3P phosphatase that localizes to ERES and negatively regulates autophagy. MTM2 binds PtdIns3P with its PH-GRAM domain in vitro and acts toward PtdIns3P in vivo. Transiently expressed MTM2 colocalizes with ATG14b, a subunit of the phosphatidylinositol 3-kinase (PtdIns3K) complex, and overexpression of MTM2 blocks autophagic flux and causes over-accumulation of ATG18a, ATG5, and ATG8a. The mtm2 mutant has higher levels of autophagy and is more tolerant to starvation, whereas MTM2 overexpression leads to reduced autophagy and sensitivity to starvation. The phenotypes of mtm2 are suppressed by ATG2 mutation, suggesting that MTM2 acts upstream of ATG2. Importantly, MTM2 does not affect the endosomal functions of PtdIns3P. Instead, MTM2 specifically colocalizes with COPII coat proteins and is cradled by the ERES-defining protein SEC16. MTM2 interacts with SEC23A with its phosphatase domain and inhibits COPII-mediated protein secretion. Finally, a role for MTM2 in salt stress response is uncovered. mtm2 resembles the halophyte Thellungiella salsuginea in its efficient vacuolar compartmentation of Na+, maintenance of chloroplast integrity, and timely regulation of autophagy-related genes. Our findings reveal a balance between PtdIns3P synthesis and turnover in autophagosome formation, and provide a new link between autophagy and COPII function.
    Keywords:  Autophagy; COPII; ER exit site; PtdIns3P; myotubularin; salt stress
    DOI:  https://doi.org/10.1080/15548627.2024.2394302
  8. Mol Pharmacol. 2024 Aug 21. pii: MOLPHARM-AR-2024-000889. [Epub ahead of print]
    The Estrogen Receptor-Related Orphan Receptors (ERRs) Regulate Autophagy through TFEB.
    McKenna Losby, Matthew Hayes, Aurore Valfort, Danesh H Sopariwala, Ryan Sanders, John K Walker, Weiyi Xu, Vihang A Narkar, Lilei Zhang, Cyrielle Billon, Thomas P Burris.
      Autophagy is an essential self-degradative and recycling mechanism that maintains cellular homeostasis. Estrogen receptor-related orphan receptors (ERRs) are fundamental in regulating cardiac metabolism and function. Previously, we showed that ERR agonists improve cardiac function in models of heart failure and induce autophagy in cardiomyocytes. Here, we characterized a mechanism by which ERRs induce the autophagy pathway in cardiomyocytes. Transcription factor EB (TFEB) is a master regulator of the autophagy-lysosome pathway and has been shown to be important in cardiac autophagy. We discovered that TFEB is a direct ERR target gene whose expression is induced by ERR agonists. Activation of ERR results in increased TFEB expression in both neonatal rat ventricular myocytes and C2C12 myoblast cells. ERR-dependent increases in TFEB expression result in increased expression of an array of TFEB target genes, which are critical for the stimulation of autophagy. Pharmacologically targeting ERR is a promising potential method for the treatment of many diseases where stimulation of autophagy may be therapeutic, including heart failure. Significance Statement Estrogen receptor-related receptor agonists function as exercise mimetics and also display efficacy in animal models of metabolic disease, obesity, and heart failure.
    Keywords:  drug discovery; heart/cardiac; nuclear receptors; steroids
    DOI:  https://doi.org/10.1124/molpharm.124.000889
  9. Autophagy. 2024 Aug 20.
    Dual roles of AtNBR1 in regulating selective autophagy via liquid-liquid phase separation and recognition of non-ubiquitinated substrates in Arabidopsis.
    He Yan, Ao Qi, Zhen Lu, Zhengtao You, Ziheng Wang, Haiying Tang, Xinghai Li, Qiao Xu, Xun Weng, Xiaojuan Du, Lifeng Zhao, Hao Wang.
      Selective macroautophagy/autophagy in metazoans involves the conserved receptors NBR1 and SQSTM1/p62. Both autophagy receptors manage ubiquitinated cargo recognition, while SQSTM1 has an additional, distinct role of facilitating liquid-liquid phase separation (LLPS) during autophagy. Given that plants lack SQSTM1, it is postulated that plant NBR1 May combine activities of both metazoan NBR1 and SQSTM1. However, the precise mechanism by which plant NBR1 recognizes non-ubiquitinated substrates and its ability to undergo LLPS during selective autophagy remain elusive. Here, we implicate both the ZZ-type zinc finger motif and the four-tryptophan domain of Arabidopsis NBR1 (AtNBR1) in the recognition of non-ubiquitinated cargo proteins. Additionally, we reveal that AtNBR1 indeed undergoes LLPS prior to ATG8-mediated autophagosome formation, crucial for heat stress resistance in Arabidopsis. Our findings unveil the dual roles of AtNBR1 in both cargo recognition and LLPS during plant autophagy and advance our understanding of NBR1-mediated autophagy in plants compared to metazoans.
    Keywords:  Arabidopsis thaliana; AtNBR1; ROF1; liquid-liquid phase separation; non-ubiquitinated cargo recognition; selective autophagy
    DOI:  https://doi.org/10.1080/15548627.2024.2391725
  10. Autophagy. 2024 Aug 22.
    Mitochondrial bioenergetics stimulates autophagy for pathological MAPT/Tau clearance in tauopathy neurons.
    Nuo Jia, Dhasarathan Ganesan, Hongyuan Guan, Yu Young Jeong, Sinsuk Han, Gavesh Rajapaksha, Marialaina Nissenbaum, Alexander W Kusnecov, Qian Cai.
      Hyperphosphorylation and aggregation of MAPT (microtubule-associated protein tau) is a pathogenic hallmark of tauopathies and a defining feature of Alzheimer disease (AD). Pathological MAPT/tau is targeted by macroautophagy/autophagy for clearance after being sequestered within autophagosomes, but autophagy dysfunction is indicated in tauopathy. While mitochondrial bioenergetic deficits have been shown to precede MAPT/tau pathology in tauopathy brains, it is unclear whether energy metabolism deficiency is involved in the pathogenesis of autophagy defects. Here, we reveal that stimulation of anaplerotic metabolism restores defective oxidative phosphorylation (OXPHOS) in tauopathy neurons which, strikingly, leads to pronounced MAPT/tau clearance by boosting autophagy functionality through enhancements of mitochondrial biosynthesis and supply of phosphatidylethanolamine for autophagosome biogenesis. Furthermore, early anaplerotic stimulation of OXPHOS elevates autophagy activity and attenuates MAPT/tau pathology, thereby counteracting memory impairment in tauopathy mice. Taken together, our study sheds light on a pivotal role of mitochondrial bioenergetic deficiency in tauopathy-related autophagy defects and suggests a new therapeutic strategy to prevent the buildup of pathological MAPT/tau in AD and other tauopathy diseases.
    Keywords:  Alzheimer; anaplerotic metabolism; autophagy; phospholipid biosynthesis; phosphorylated MAPT/tau; tauopathy
    DOI:  https://doi.org/10.1080/15548627.2024.2392408
  11. EMBO Rep. 2024 Aug 16.
    WIPI2b recruitment to phagophores and ATG16L1 binding are regulated by ULK1 phosphorylation.
    Andrea Gubas, Eleanor Attridge, Harold Bj Jefferies, Taki Nishimura, Minoo Razi, Simone Kunzelmann, Yuval Gilad, Thomas J Mercer, Michael M Wilson, Adi Kimchi, Sharon A Tooze.
      One of the key events in autophagy is the formation of a double-membrane phagophore, and many regulatory mechanisms underpinning this remain under investigation. WIPI2b is among the first proteins to be recruited to the phagophore and is essential for stimulating autophagy flux by recruiting the ATG12-ATG5-ATG16L1 complex, driving LC3 and GABARAP lipidation. Here, we set out to investigate how WIPI2b function is regulated by phosphorylation. We studied two phosphorylation sites on WIPI2b, S68 and S284. Phosphorylation at these sites plays distinct roles, regulating WIPI2b's association with ATG16L1 and the phagophore, respectively. We confirm WIPI2b is a novel ULK1 substrate, validated by the detection of endogenous phosphorylation at S284. Notably, S284 is situated within an 18-amino acid stretch, which, when in contact with liposomes, forms an amphipathic helix. Phosphorylation at S284 disrupts the formation of the amphipathic helix, hindering the association of WIPI2b with membranes and autophagosome formation. Understanding these intricacies in the regulatory mechanisms governing WIPI2b's association with its interacting partners and membranes, holds the potential to shed light on these complex processes, integral to phagophore biogenesis.
    Keywords:  Amphipathic Helix; Autophagosome; Autophagy; Kinase; WIPIs
    DOI:  https://doi.org/10.1038/s44319-024-00215-5
  12. Curr Microbiol. 2024 Aug 20. 81(10): 315
    Nucleophagy in Aspergillus oryzae is Mediated by Autophagosome Formation and Vacuole-Mediated Degradation.
    Mau Hashimoto, Satoshi Kimura, Manabu Arioka.
      We previously reported autophagy-mediated degradation of nuclei, nucleophagy, in the filamentous fungus Aspergillus oryzae. In this study, we examined whether nuclei are degraded as a whole. We generated A. oryzae mutants deleted for orthologs of Saccharomyces cerevisiae YPT7 and ATG15 which are required, respectively, for autophagosome-vacuole fusion and vacuolar degradation of autophagic bodies. Degradation of histone H2B-EGFP under starvation conditions was greatly decreased in the ΔAoypt7 and ΔAoatg15 mutants. Fluorescence and electron microscopic observations showed that autophagosomes and autophagic bodies surrounding the entire nuclei were accumulated in the cytoplasm of ΔAoypt7 and the vacuole of ΔAoatg15, respectively. These results indicate that nuclei are engulfed in the autophagosomes as a whole and transported/released into the vacuolar lumen where they are degraded.
    DOI:  https://doi.org/10.1007/s00284-024-03838-y
  13. Sci Rep. 2024 08 16. 14(1): 18974
    TRIM44 enhances autophagy via SQSTM1 oligomerization in response to oxidative stress.
    Yuqin Wang, Lin Lyu, Trung Vu, Nami McCarty.
      The deubiquitinase tripartite motif containing 44 (TRIM44) plays a critical role in linking the proteotoxic stress response with autophagic degradation, which is significant in the context of cancer and neurological diseases. Although TRIM44 is recognized as a prognostic marker in various cancers, the complex molecular mechanisms through which it facilitates autophagic degradation, particularly under oxidative stress conditions, have not been fully explored. In this study, we demonstrate that TRIM44 significantly enhances autophagy in response to oxidative stress, reducing cytotoxicity in cancer cells treated with arsenic trioxide. Our research emphasizes the critical role of the posttranslational modification of sequestosome-1 (SQSTM1) and its importance in improving sequestration during autophagic degradation under oxidative stress. We found that TRIM44 notably promotes SQSTM1 oligomerization in both PB1 domain-dependent and oxidation-dependent manners. Furthermore, TRIM44 amplifies the interaction between protein kinase A and oligomerized SQSTM1, leading to enhanced phosphorylation of SQSTM1 at S349. This phosphorylation event activates NFE2L2, a key transcription factor in the oxidative stress response, highlighting the importance of TRIM44 in modulating SQSTM1-mediated autophagy. Our findings support that TRIM44 plays pivotal roles in regulating autophagic sensitivity to oxidative stress, with implications for cancer, aging, aging-associated diseases, and neurodegenerative disorders.
    DOI:  https://doi.org/10.1038/s41598-024-67832-x
  14. Front Aging Neurosci. 2024 ;16 1387931
    O-GlcNAc impacts mitophagy via the PINK1-dependent pathway.
    Ibtihal M Alghusen, Marisa S Carman, Heather M Wilkins, Taylor A Strope, Caleb Gimore, Halyna Fedosyuk, Jad Shawa, Sophiya John Ephrame, Aspin R Denson, Xiaowan Wang, Russell H Swerdlow, Chad Slawson.
       Background: The accumulation of dysfunctional mitochondria is an early feature of Alzheimer's disease (AD). The impaired turnover of damaged mitochondria increases reactive oxygen species production and lowers ATP generation, leading to cellular toxicity and neurodegeneration. Interestingly, AD exhibits a disruption in the global post-translational modification β-N-acetylglucosamine (O-GlcNAc). O-GlcNAc is a ubiquitous single sugar modification found in the nuclear, cytoplasmic, and mitochondrial proteins. Cells maintain a homeostatic level of O-GlcNAc by cycling the addition and removal of the sugar by O-GlcNAc transferase (OGT) or O-GlcNAcase (OGA), respectively.
    Methods: We used patient-derived induced pluripotent stem cells, a transgenic mouse model of AD, SH-SY5Y neuroblastoma cell lines to examine the effect of sustained O-GlcNAcase inhibition by Thiamet-G (TMG) or OGT deficiency on mitophagy using biochemical analyses.
    Results: Here, we established an essential role for O-GlcNAc in regulating mitophagy (mitochondria-selective autophagy). Stimulating mitophagy using urolithin A (UA) decreases cellular O-GlcNAc and elevates mitochondrial O-GlcNAc. Sustained elevation in O-GlcNAcylation via pharmacologically inhibiting OGA using Thiamet-G (TMG) increases the mitochondrial level of mitophagy protein PTEN-induced kinase 1 (PINK1) and autophagy-related protein light chain 3 (LC3). Moreover, we detected O-GlcNAc on PINK1 and TMG increases its O-GlcNAcylation level. Conversely, decreasing cellular O-GlcNAcylation by knocking down OGT decreases both PINK1 protein expression and LC3 protein expression. Mitochondria isolated from CAMKII-OGT-KO mice also had decreased PINK1 and LC3. Moreover, human brain organoids treated with TMG showed significant elevation in LC3 compared to control. However, TMG-treated AD organoids showed no changes in LC3 expression.
    Conclusion: Collectively, these data demonstrate that O-GlcNAc plays a crucial role in the activation and progression of mitophagy, and this activation is disrupted in AD.
    Keywords:  Alzheimer’s disease; O-GlcNAc; OGT; PTEN-induced kinase-1; mitophagy
    DOI:  https://doi.org/10.3389/fnagi.2024.1387931
  15. Pathol Res Pract. 2024 Aug 13. pii: S0344-0338(24)00434-5. [Epub ahead of print]262 155523
    The paradox of autophagy in cancer: NEAT1's role in tumorigenesis and therapeutic resistance.
    Salem Salman Almujri, Waleed Hassan Almalki.
      Cancer remains a current active problem of modern medicine, a process during which cell growth and proliferation become uncontrolled. However, the role of autophagy in the oncological processes is counterintuitive and, at the same time, increasingly influential on the formation, development, and response to therapy of oncological diseases. Autophagy is a vital cellular process that removes defective proteins and organelles and supports cellular homeostasis. Autophagy can enhance the ability to form new tumors and suppress this formation in cancer. The dual potential of apoptosis may be the reason for this duality in either promoting or impeding the survival of cancer cells, depending on the situation, including starvation or treatment stress. Furthermore, long non-coding RNA NEAT1, which has been linked to several stages of carcinogenesis and in all forms of the illness, has drawn attention as a major player in cancer biology. NEAT1 is a structural portion of nuclear paraspeckles and has roles in deactivating expression in both transcriptional and post-transcriptional levels. NEAT1 acts in carcinogenesis in numerous ways, comprising interactions with microRNAs, the influence of gene articulation, regulation of epigenetics, and engagement in signalling cascades. In addition, the complexity of NEAT1's role in cancer occurrence is amplified by its place in regulating cancer stem cells and the tumor microenvironment. NEAT1's interaction with autophagy further complicates the already complicated function of this RNA in cancer biology. NEAT1 has been linked to autophagy in several types of cancer, influencing autophagy pathways and altering its stress response and tumor cell viability. Understanding the interrelation between NEAT1, autophagy, and cancer will enable practitioners to identify novel treatment targets and approaches to disrupt oncogenic processes, reduce the occurrence of treatment resistance, and increase patient survival rates. Specialized treatment strategies and regimens are thus achievable. In the present review, the authors analyze sophisticated relationship schemes in cancer: The NEAT1 pathway and the process of autophagy.
    Keywords:  Autophagy; Cancer; Long Non-Coding RNA; Molecular Mechanisms; NEAT1; Therapeutic Resistance; Tumorigenesis
    DOI:  https://doi.org/10.1016/j.prp.2024.155523
  16. Front Neurosci. 2024 ;18 1410139
    Usp14 down-regulation corrects sleep and circadian dysfunction of a Drosophila model of Parkinson's disease.
    Mariavittoria Favaro, Sofia Mauri, Greta Bernardo, Mauro A Zordan, Gabriella M Mazzotta, Elena Ziviani.
      PD is a complex, multifactorial neurodegenerative disease, which occurs sporadically in aged population, with some genetically linked cases. Patients develop a very obvious locomotor phenotype, with symptoms such as bradykinesia, resting tremor, muscular rigidity, and postural instability. At the cellular level, PD pathology is characterized by the presence of intracytoplasmic neurotoxic aggregates of misfolded proteins and dysfunctional organelles, resulting from failure in mechanisms of proteostasis. Nonmotor symptoms, such as constipation and olfactory deficits, are also very common in PD. They include alteration in the circadian clock, and defects in the sleep-wake cycle, which is controlled by the clock. These non-motor symptoms precede the onset of the motor symptoms by many years, offering a window of therapeutic intervention that could delay-or even prevent-the progression of the disease. The mechanistic link between aberrant circadian rhythms and neurodegeneration in PD is not fully understood, although proposed underlying mechanisms include alterations in protein homeostasis (proteostasis), which can impact protein levels of core components of the clock. Loss of proteostasis depends on the progressive pathological decline in the proteolytic activity of two major degradative systems, the ubiquitin-proteasome and the lysosome-autophagy systems, which is exacerbated in age-dependent neurodegenerative conditions like PD. Accordingly, it is known that promoting proteasome or autophagy activity increases lifespan, and rescues the pathological phenotype of animal models of neurodegeneration, presumably by enhancing the degradation of misfolded proteins and dysfunctional organelles, which are known to accumulate in these models, and to induce intracellular damage. We can enhance proteostasis by pharmacologically inhibiting or down-regulating Usp14, a proteasome-associated deubiquitinating enzyme (DUB). In a previous work, we showed that inhibition of Usp14 enhances the activity of the ubiquitin-proteasome system (UPS), autophagy and mitophagy, and abolishes motor symptoms of two well-established fly models of PD that accumulate dysfunctional mitochondria. In this work we extended the evidence on the protective effect of Usp14 down-regulation, and investigated the beneficial effect of down-regulating Usp14 in a Pink1 Drosophila model of PD that develop circadian and sleep dysfunction. We show that down-regulation of Usp14 ameliorates sleep disturbances and circadian defects that are associated to Pink1 KO flies.
    Keywords:  Drosophila; PINK1; USP14; circadian clock; mitochondrial fission; sleep
    DOI:  https://doi.org/10.3389/fnins.2024.1410139
  17. Autophagy. 2024 Aug 22.
    Mapping autophagy-related membrane contact site proteins and complexes with AutoMCS Navigator.
    Tianyuan Liu, Xianrun Pan, Liping Ren, Xiucai Ye, Kai Zheng, Yang Zhang.
      In eukaryotic cells, membrane contact sites (MCSs) mediate interactions and communication between organelles by bringing their membranes into close proximity without fusion. These sites play crucial roles in intracellular transport, signal transduction, and the regulation of organelle functions. In a recent study, we compiled data on MCS proteins and complexes from publications to create the MCSdb database. During data compilation, we discovered that many MCSs, their associated proteins, and complexes are highly relevant to macroautophagy/autophagy. To elucidate the role of MCSs in autophagy, we reorganized the autophagy-related MCS proteins and complexes from MCSdb, creating a data map called AutoMCS Navigator. The current version of this map includes 30 complexes and 84 proteins, covering 13 different MCSs and 7 species. Meanwhile, we embedded a dedicated webpage for AutoMCS Navigator on the MCSdb website. This webpage features an orchestrated visual guide that hierarchically displays MCS proteins and complexes involved in autophagy. In summary, our research has developed a user-friendly visual map for querying, browsing, and visualizing detailed information on autophagy-related MCS proteins and complexes. This tool offers researchers easy access to understand autophagy-related MCS structure, assembly, functions, and therapeutic strategies for related diseases. AutoMCS Navigator is freely available at https://cellknowledge.com.cn/mcsdb/autophagy.html.
    Keywords:  Autophagy; complex; database; membrane contact site; organelle; protein
    DOI:  https://doi.org/10.1080/15548627.2024.2394291
  18. Diabetes Ther. 2024 Aug 21.
    Targeting Autophagy: A Promising Therapeutic Strategy for Diabetes Mellitus and Diabetic Nephropathy.
    Qi-Rui Li, Hui-Ying Xu, Rui-Ting Ma, Yuan-Yuan Ma, Mei-Juan Chen.
      Diabetes mellitus (DM) significantly impairs patients' quality of life, primarily because of its complications, which are the leading cause of mortality among individuals with the disease. Autophagy has emerged as a key process closely associated with DM, including its complications such as diabetic nephropathy (DN). DN is a major complication of DM, contributing significantly to chronic kidney disease and renal failure. The intricate connection between autophagy and DM, including DN, highlights the potential for new therapeutic targets. This review examines the interplay between autophagy and these conditions, aiming to uncover novel approaches to treatment and enhance our understanding of their underlying pathophysiology. It also explores the role of autophagy in maintaining renal homeostasis and its involvement in the development and progression of DM and DN. Furthermore, the review discusses natural compounds that may alleviate these conditions by modulating autophagy.
    Keywords:  Autophagy; Diabetes mellitus; Diabetic nephropathy; Natural substances
    DOI:  https://doi.org/10.1007/s13300-024-01641-3
  19. Cell Biol Int. 2024 Aug 20.
    Inhibitors of the mTOR signaling pathway can play an important role in breast cancer immunopathogenesis.
    Sulieman I Shelash Al-Hawary, Farag M A Altalbawy, Saade Abdalkareem Jasim, Renuka Jyothi S, Azfar Jamal, Mohammed M Naiyer, Shriya Mahajan, Hitesh Kalra, Mohammed Abed Jawad, Ahmed Hussein Zwamel.
      This study explores the critical role of inhibitors targeting the mammalian target of rapamycin (mTOR) signaling pathway in breast cancer research and treatment. The mTOR pathway, a central regulator of cellular processes, has been identified as a crucial factor in the development and progression of breast cancer. The essay explains the complex molecular mechanisms through which mTOR inhibitors, such as rapamycin and its analogs, exert their anticancer effects. These inhibitors can stop cell growth, proliferation, and survival in breast cancer cells by blocking critical signaling pathways within the mTOR pathway. Furthermore, the essay discusses the implications of using mTOR inhibitors as a comprehensive therapeutic strategy. It emphasizes the potential benefits of combining mTOR inhibitors with other treatment approaches to enhance the effectiveness of breast cancer treatment. The evolving landscape of breast cancer research underscores the significance of mTOR as a therapeutic target and highlights ongoing efforts to improve and optimize mTOR inhibitors for clinical use. In conclusion, the essay asserts that inhibitors of the mTOR signaling pathway offer a promising approach in the fight against breast cancer. These inhibitors provide a focused and effective intervention targeting specific dysregulations within the mTOR pathway. As research advances, the integration of mTOR inhibitors into customized combination therapies holds excellent potential for shaping a more effective and personalized approach to breast cancer treatment, ultimately leading to improved outcomes for individuals affected by this complex and diverse disease.
    Keywords:  breast cancer; chemotherapy; mTOR pathway
    DOI:  https://doi.org/10.1002/cbin.12231
  20. J Cell Biochem. 2024 Aug 22. e30641
    FOXO3 Activates MFN2 Expression to Maintain the Autophagy Response in Cancer Cells Under Amino Acid Deprivation.
    Xu Jiang, Jing Wang, Fang Ma, Yuyun Li.
      The lack of amino acids triggers the autophagic response. Some studies have shown such starvation conditions also induce mitochondrial fusion, revealing a close correlation between the two processes. Although Mitofusin-2 (MFN2) has been demonstrated to play a role in fusion regulation, its role in the autophagic response and the variables that activate MFN2 under stress remain unknown. In this investigation, we screened and confirmed that forkhead box protein O3 (FOXO3) participates in MFN2's expression during short periods of starvation. Luciferase reporter test proved that FOXO3 facilitates MFN2's transcription by binding to its promoter region, and FOXO3 downregulation directly depresses MFN2's expression. Consequently, inhibiting the FOXO3-MFN2 axis results in the loss of mitochondrial fusion, disrupting the normal morphology of mitochondria, impairing the degradation of substrates, and reducing autophagosome accumulation, ultimately leading to the blockage of the autophagy. In conclusion, our work demonstrates that the FOXO3-MFN2 pathway is essential for adaptive changes in mitochondrial morphology and cellular autophagy response under nutritional constraints.
    Keywords:  FOXO3; MFN2; autophagy; mitochondrial fusion; starvation stress
    DOI:  https://doi.org/10.1002/jcb.30641
  21. Front Cell Dev Biol. 2024 ;12 1431566
    Lysosomal biogenesis and function in osteoclasts: a comprehensive review.
    Junchen Jiang, Rufeng Ren, Weiyuan Fang, Jiansen Miao, Zijun Wen, Xiangyang Wang, Jiake Xu, Haiming Jin.
      Lysosomes serve as catabolic centers and signaling hubs in cells, regulating a multitude of cellular processes such as intracellular environment homeostasis, macromolecule degradation, intracellular vesicle trafficking and autophagy. Alterations in lysosomal level and function are crucial for cellular adaptation to external stimuli, with lysosome dysfunction being implicated in the pathogenesis of numerous diseases. Osteoclasts (OCs), as multinucleated cells responsible for bone resorption and maintaining bone homeostasis, have a complex relationship with lysosomes that is not fully understood. Dysregulated function of OCs can disrupt bone homeostasis leading to the development of various bone disorders. The regulation of OC differentiation and bone resorption for the treatment of bone disease have received considerable attention in recent years, yet the role and regulation of lysosomes in OCs, as well as the potential therapeutic implications of intervening in lysosomal biologic behavior for the treatment of bone diseases, remain relatively understudied. This review aims to elucidate the mechanisms involved in lysosomal biogenesis and to discuss the functions of lysosomes in OCs, specifically in relation to differentiation, bone resorption, and autophagy. Finally, we explore the potential therapeutic implication of targeting lysosomes in the treatment of bone metabolic disorders.
    Keywords:  autophagy; bone metabolic disorders; bone resorption; lysosome; osteoclast
    DOI:  https://doi.org/10.3389/fcell.2024.1431566
  22. Genes Dev. 2024 Aug 22.
    An old dog with new tricks: TFEB promotes syncytin expression and cell fusion in the human placenta.
    Stephen J Renaud.
      In the human placenta, cell fusion is crucial for forming the syncytiotrophoblast, a multinucleated giant cell essential for maintaining pregnancy and ensuring fetal health. The formation of the syncytiotrophoblast is catalyzed by the evolutionarily modern fusogens syncytin-1 and syncytin-2. In this issue of Genes & Development, Esbin and colleagues (doi:10.1101/gad.351633.124) reveal a critical role for the transcription factor TFEB in the regulation of syncytin expression and the promotion of trophoblast fusion. Notably, TFEB's pro-fusion role operates independently of its well-known functions in lysosome biogenesis and autophagy, suggesting that TFEB has acquired additional functions to promote cell fusion in the human placenta.
    Keywords:  TFEB; cell fusion; placenta; single molecule imaging; syncytin; transcription factor
    DOI:  https://doi.org/10.1101/gad.352198.124
  23. Bone Res. 2024 Aug 21. 12(1): 45
    Rejuvenation of BMSCs senescence by pharmacological enhancement of TFEB-mediated autophagy alleviates aged-related bone loss and extends lifespan in middle aged mice.
    Ziwei Luo, Wanyi Wei, Dawei Qiu, Zixia Su, Liangpu Liu, Honghai Zhou, Hao Cui, Li Yang.
      Bone marrow stromal/stem cells (BMSCs) are generally considered as common progenitors for both osteoblasts and adipocytes in the bone marrow, but show preferential differentiation into adipocytes rather than osteoblasts under aging, thus leading to senile osteoporosis. Accumulated evidences indicate that rejuvenation of BMSCs by autophagic enhancement delays bone aging. Here we synthetized and demonstrated a novel autophagy activator, CXM102 that could induce autophagy in aged BMSCs, resulting in rejuvenation and preferential differentiation into osteoblasts of BMSCs. Furthermore, CXM102 significantly stimulated bone anabolism, reduced marrow adipocytes, and delayed bone loss in middle-age male mice. Mechanistically, CXM102 promoted transcription factor EB (TFEB) nuclear translocation and favored osteoblasts formation both in vitro and in vivo. Moreover, CXM102 decreased serum levels of inflammation and reduced organ fibrosis, leading to a prolonger lifespan in male mice. Our results indicated that CXM102 could be used as an autophagy inducer to rejuvenate BMSCs and shed new lights on strategies for senile osteoporosis and healthyspan improvement.
    DOI:  https://doi.org/10.1038/s41413-024-00351-7
  24. Brain. 2024 Aug 21. pii: awae275. [Epub ahead of print]
    Targeting spinal mechanistic target of rapamycin complex 2 alleviates inflammatory and neuropathic pain.
    Calvin Wong, Luis David Rodriguez-Hernandez, Kevin C Lister, Ning Gu, Weihua Cai, Mehdi Hooshmandi, Jonathan Fan, Nicole Brown, Vivienne Nguyen, Alfredo Ribeiro-da-Silva, Robert P Bonin, Arkady Khoutorsky.
      The development and maintenance of chronic pain involves the reorganization of spinal nociceptive circuits. The mechanistic target of rapamycin complex 2 (mTORC2), a central signaling hub that modulates both actin-dependent structural changes and mTORC1-dependent mRNA translation, plays key roles in hippocampal synaptic plasticity and memory formation. However, its function in spinal plasticity and chronic pain is poorly understood. Here we show that pharmacological activation of spinal mTORC2 induces pain hypersensitivity, whereas its inhibition, using downregulation of the mTORC2-defining component Rictor, alleviates both inflammatory and neuropathic pain. Cell-type-specific deletion of Rictor showed that the selective inhibition of mTORC2 in a subset of excitatory neurons impairs spinal synaptic potentiation and alleviates inflammation-induced mechanical and thermal hypersensitivity, and nerve injury-induced heat hyperalgesia. The ablation of mTORC2 in inhibitory interneurons strongly alleviated nerve injury-induced mechanical hypersensitivity. Our findings reveal the role of mTORC2 in chronic pain and highlight its cell-type-specific functions in mediating pain hypersensitivity in response to peripheral inflammation and nerve injury.
    Keywords:  AKT; Rictor; inflammatory pain; mTORC2; neuropathic pain; spinal cord
    DOI:  https://doi.org/10.1093/brain/awae275
  25. Front Endocrinol (Lausanne). 2024 ;15 1374644
    The pivotal role of dysregulated autophagy in the progression of non-alcoholic fatty liver disease.
    Qiaohui Shen, Ming Yang, Song Wang, Xingyu Chen, Sulan Chen, Rui Zhang, Zhuang Xiong, Yan Leng.
      Non-alcoholic fatty liver disease (NAFLD) is a clinicopathologic syndrome characterized by excessive fat deposition in hepatocytes and a major cause of end-stage liver disease. Autophagy is a metabolic pathway responsible for degrading cytoplasmic products and damaged organelles, playing a pivotal role in maintaining the homeostasis and functionality of hepatocytes. Recent studies have shown that pharmacological intervention to activate or restore autophagy provides benefits for liver function recovery by promoting the clearance of lipid droplets (LDs) in hepatocytes, decreasing the production of pro-inflammatory factors, and inhibiting activated hepatic stellate cells (HSCs), thus improving liver fibrosis and slowing down the progression of NAFLD. This article summarizes the physiological process of autophagy, elucidates the close relationship between NAFLD and autophagy, and discusses the effects of drugs on autophagy and signaling pathways from the perspectives of hepatocytes, kupffer cells (KCs), and HSCs to provide assistance in the clinical management of NAFLD.
    Keywords:  autolysosome; autophagosome; autophagy; hepatic stellate cells; hepatocytes; kupffer cells; non-alcoholic fatty liver disease
    DOI:  https://doi.org/10.3389/fendo.2024.1374644
  26. Parasit Vectors. 2024 Aug 19. 17(1): 347
    Ac-HSP20 regulates autophagy and promotes the encystation of Acanthamoeba castellanii by inhibiting the PI3K/AKT/mTOR signaling pathway.
    Siyao Guo, Di Liu, Xi Wan, Dingrui Guo, Meiyu Zheng, Wenyu Zheng, Xianmin Feng.
       BACKGROUND: The encystation of Acanthamoeba castellanii has important ecological and medical significance. Blocking encystation is the key to preventing transmission and curing infections caused by A. castellanii. The formation of autophagosomes is one of the most important changes that occur during the encystation of Acanthamoeba. Our previous studies have shown that the heat shock protein 20 of A. castellanii (Ac-HSP20) is involved in its encystation. This study aimed to determine the role and mechanism of Ac-HSP20 in regulating autophagy involved in the encystation of A. castellanii.
    METHODS: Immunofluorescence assay, western blotting and transmission electron microscopy were used to analyze the dynamic changes in autophagy during the initiation and continuation of encystation. The knockdown of Ac-HSP20 was performed to clarify its regulation of encystation and autophagy and to elucidate the molecular mechanism by which Ac-HSP20 participates in autophagy to promote cyst maturation.
    RESULTS: The encystation rates and autophagosomes were significantly decreased by treatment with the autophagy inhibitor 3-MA. The autophagy marker LC3B and autophagic lysosomes increased with the induced duration of encystation and reached the maximum at 48 h. The encystation rate, LC3B expression and autophagosomes decreased when Ac-HSP20 was knocked down by siRNA transfection. In addition, the expression levels of Ac-HSP20 and LC3B increased and the expressions of p-AKT and p-mTOR decreased after 48 h of encystation without knockdown. However, the expressions of p-AKT and p-mTOR increased while the expression of LC3B decreased under the knockdown of Ac-HSP20. Furthermore, the protein expression of LC3B increased when the PI3K/AKT/mTOR signaling pathway was inhibited but decreased when the pathway was activated.
    CONCLUSIONS: The results demonstrated that autophagy is positively correlated with the encystation of A. castellanii, and Ac-HSP20 regulates autophagy to maintain the homeostasis of A. castellanii by inhibiting the PI3K /AKT /mTOR signaling pathway, thus promoting the maturation and stability of encystation.
    Keywords:   Acanthamoeba castellanii ; Autophagy; Encystation; HSP20; PI3K/AKT/mTOR; Protozoa
    DOI:  https://doi.org/10.1186/s13071-024-06436-w
  27. Cell Rep. 2024 Aug 20. pii: S2211-1247(24)01014-3. [Epub ahead of print]43(9): 114663
    Non-canonical metabolic and molecular effects of calorie restriction are revealed by varying temporal conditions.
    Heidi H Pak, Allison N Grossberg, Rachel R Sanderfoot, Reji Babygirija, Cara L Green, Mikaela Koller, Monika Dzieciatkowska, Daniel A Paredes, Dudley W Lamming.
      Calorie restriction (CR) extends lifespan and healthspan in diverse species. Comparing ad libitum- and CR-fed mice is challenging due to their significantly different feeding patterns, with CR-fed mice consuming their daily meal in 2 h and then subjecting themselves to a prolonged daily fast. Here, we examine how ad libitum- and CR-fed mice respond to tests performed at various times and fasting durations and find that the effects of CR-insulin sensitivity, circulating metabolite levels, and mechanistic target of rapamycin 1 (mTORC1) activity-result from the specific temporal conditions chosen, with CR-induced improvements in insulin sensitivity observed only after a prolonged fast, and the observed differences in mTORC1 activity between ad libitum- and CR-fed mice dependent upon both fasting duration and the specific tissue examined. Our results demonstrate that much of our understanding of the effects of CR are related to when, relative to feeding, we choose to examine the mice.
    Keywords:  CP: Metabolism; aging; calorie restriction; dietary restriction; fasting; lifespan; mTOR; time-restricted feeding
    DOI:  https://doi.org/10.1016/j.celrep.2024.114663
  28. Acta Biochim Biophys Sin (Shanghai). 2024 Aug 23.
    FTO-mediated m 6A demethylation of ULK1 mRNA promotes autophagy and activation of hepatic stellate cells in liver fibrosis.
    Tingjuan Huang, Chunhong Zhang, Junjie Ren, Qizhi Shuai, Xiaonan Li, Xuewei Li, Jun Xie, Jun Xu.
      The activation of hepatic stellate cells (HSCs) is central to the occurrence and development of liver fibrosis. Our previous studies showed that autophagy promotes HSC activation and ultimately accelerates liver fibrosis. Unc-51-like autophagy activating kinase 1 (ULK1) is an autophagic initiator in mammals, and N 6-methyladenosine (m 6A) modification is closely related to autophagy. In this study, we find that the m 6A demethylase fat mass and obesity-associated protein (FTO), which is the m 6A methylase with the most significant difference in expression, is upregulated during HSC activation and bile duct ligation (BDL)-induced hepatic fibrosis. Importantly, we identify that FTO overexpression aggravates HSC activation and hepatic fibrosis via autophagy. Mechanistically, compared with other autophagy-related genes, ULK1 is a target of FTO because FTO mainly mediates the m 6A demethylation of ULK1 and upregulates its expression, thereby enhancing autophagy and the activation of HSCs. Notably, the m 6A reader YTH domain-containing protein 2 (YTHDC2) decreases ULK1 mRNA level by recognizing the m 6A binding site and ultimately inhibiting autophagy and HSC activation. Taken together, our findings highlight m6A-dependent ULK1 as an essential regulator of HSC autophagy and reveal that ULK1 is a novel potential therapeutic target for hepatic fibrosis treatment.
    Keywords:  FTO; ULK1; autophagy; hepatic stellate cells; m A methylation
    DOI:  https://doi.org/10.3724/abbs.2024098
  29. J Neurochem. 2024 Aug 18.
    The autophagy proteome in the brain.
    Vitor I Ito-Silva, Bradley J Smith, Daniel Martins-de-Souza.
      As one of the most important cellular housekeepers, autophagy directly affects cellular health, homeostasis, and function. Even though the mechanisms behind autophagy are well described, how molecular alterations and dysfunctions can lead to pathology in disease contexts still demands deeper investigation. Proteomics is a widely employed tool used to investigate molecular alterations associated with pathological states and has proven useful in identifying alterations in protein expression levels and post-translational modifications in autophagy. In this narrative review, we expand on the molecular mechanisms behind autophagy and its regulation, and further compile recent literature associating autophagy disturbances in context of brain disorders, utilizing discoveries from varying models and species from rodents and cellular models to human post-mortem brain samples. To outline, the canonical pathways of autophagy, the effects of post-translational modifications on regulating each step of autophagy, and the future directions of proteomics in autophagy will be discussed. We further aim to suggest how advancing proteomics can help further unveil molecular mechanisms with regard to neurological disorders.
    Keywords:  autophagosomes; diseases; impairment; mass spectrometry; proteomics
    DOI:  https://doi.org/10.1111/jnc.16204
  30. Mol Neurobiol. 2024 Aug 20.
    Contactin -Associated protein1 Regulates Autophagy by Modulating the PI3K/AKT/mTOR Signaling Pathway and ATG4B Levels in Vitro and in Vivo.
    Yan Zou, Xiao Zhang, Xin-Yi Chen, Xiao-Fang Ma, Xiao-Yan Feng, Yang Sun, Tao Ma, Quan-Hong Ma, Xu-Dong Zhao, De-En Xu.
      Contactin-associated protein1 (Caspr1) plays an important role in the formation and stability of myelinated axons. In Caspr1 mutant mice, autophagy-related structures accumulate in neurons, causing axonal degeneration; however, the mechanism by which Caspr1 regulates autophagy remains unknown. To illustrate the mechanism of Caspr1 in autophagy process, we demonstrated that Caspr1 knockout in primary neurons from mice along with human cell lines, HEK-293 and HeLa, induced autophagy by downregulating the PI3K/AKT/mTOR signaling pathway to promote the conversion of microtubule-associated protein light chain 3 I (LC3-I) to LC3-II. In contrast, Caspr1 overexpression in cells contributed to the upregulation of this signaling pathway. We also demonstrated that Caspr1 knockout led to increased LC3-I protein expression in mice. In addition, Caspr1 could inhibit the expression of autophagy-related 4B cysteine peptidase (ATG4B) protein by directly binding to ATG4B in overexpressed Caspr1 cells. Intriguingly, we found an accumulation of ATG4B in the Golgi apparatuses of cells overexpressing Caspr1; therefore, we speculate that Caspr1 may restrict ATG4 secretion from the Golgi apparatus to the cytoplasm. Collectively, our results indicate that Caspr1 may regulate autophagy by modulating the PI3K/AKT/mTOR signaling pathway and the levels of ATG4 protein, both in vitro and in vivo. Thus, Caspr1 can be a potential therapeutic target in axonal damage and demyelinating diseases.
    Keywords:  AKT; ATG4B; Autophagy; Axon; Contactin-associated protein; Demyelinating disease; Golgi apparatus; LC3; MTOR; PI3K
    DOI:  https://doi.org/10.1007/s12035-024-04425-9
  31. FEBS Lett. 2024 Aug 07.
    GABARAP interacts with EGFR - supporting the unique role of this hAtg8 protein during receptor trafficking.
    Alina Üffing, Oliver H Weiergräber, Melanie Schwarten, Silke Hoffmann, Dieter Willbold.
      The human Atg8 family member GABARAP is involved in numerous autophagy-related and -unrelated processes. We recently observed that specifically the deficiency of GABARAP enhances epidermal growth factor receptor (EGFR) degradation upon ligand stimulation. Here, we report on two putative LC3-interacting regions (LIRs) within EGFR, the first of which (LIR1) is selected as a GABARAP binding site in silico. Indeed, in vitro interaction studies reveal preferential binding of LIR1 to GABARAP and GABARAPL1. Our X-ray data demonstrate interaction of core LIR1 residues FLPV with both hydrophobic pockets of GABARAP suggesting canonical binding. Although LIR1 occupies the LIR docking site, GABARAP Y49 and L50 appear dispensable in this case. Our data support the hypothesis that GABARAP affects the fate of EGFR at least in part through direct binding.
    Keywords:  Alphafold; LC3‐interacting region; NMR; X‐ray; canonical binding; complex structure; paralog‐specificity; surface receptor
    DOI:  https://doi.org/10.1002/1873-3468.14997
  32. New Phytol. 2024 Aug 19.
    Strigolactones positively regulate HY5-dependent autophagy and the degradation of ubiquitinated proteins in response to cold stress in tomato.
    Cheng Chi, Xinlin Chen, Changan Zhu, Jiajian Cao, Hui Li, Ying Fu, Guochen Qin, Jun Zhao, Jingquan Yu, Jie Zhou.
      Autophagy, involved in protein degradation and amino acid recycling, plays a key role in plant development and stress responses. However, the relationship between autophagy and phytohormones remains unclear. We used diverse methods, including CRISPR/Cas9, ultra-performance liquid chromatography coupled with tandem mass spectrometry, chromatin immunoprecipitation, electrophoretic mobility shift assays, and dual-luciferase assays to explore the molecular mechanism of strigolactones in regulating autophagy and the degradation of ubiquitinated proteins under cold stress in tomato (Solanum lycopersicum). We show that cold stress induced the accumulation of ubiquitinated proteins. Mutants deficient in strigolactone biosynthesis were more sensitive to cold stress with increased accumulation of ubiquitinated proteins. Conversely, treatment with the synthetic strigolactone analog GR245DS enhanced cold tolerance in tomato, with elevated levels of accumulation of autophagosomes and transcripts of autophagy-related genes (ATGs), and reduced accumulation of ubiquitinated proteins. Meanwhile, cold stress induced the accumulation of ELONGATED HYPOCOTYL 5 (HY5), which was triggered by strigolactones. HY5 further trans-activated ATG18a transcription, resulting in autophagy formation. Mutation of ATG18a compromised strigolactone-induced cold tolerance, leading to decreased formation of autophagosomes and increased accumulation of ubiquitinated proteins. These findings reveal that strigolactones positively regulate autophagy in an HY5-dependent manner and facilitate the degradation of ubiquitinated proteins under cold conditions in tomato.
    Keywords:  ELONGATED HYPOCOTYL 5 (HY5); autophagy; autophagy‐related gene (ATG); cold stress; strigolactones (SLs); tomato
    DOI:  https://doi.org/10.1111/nph.20058
  33. J Clin Neuromuscul Dis. 2024 Sep 01. 26(1): 12-15
    Diagnosing X-Linked Myopathy With Excessive Autophagy After 30 years: Genetic, Ultrasonographic, and Electrodiagnostic Findings.
    Vanessa Dwairi, Alaina Giacobbe, Sasa Zivkovic, David Lacomis.
       ABSTRACT: X-linked myopathy with excessive autophagy is a rare disorder caused by a mutation in the vacuolar ATPase assembly factor gene which causes slowly progressive early onset proximal weakness and loss of ambulation by the age of 50-70 years. Electrodiagnostic (EDx) testing usually shows widespread complex repetitive and myotonic discharges, even in muscles unaffected clinically. We report a 65-year-old man who presented with progressive proximal weakness since his teenage years. Extensive workup over 30 years revealed inconclusive EDx and muscle histopathology findings. The diagnosis was finally made with genetic testing. Subsequent neuromuscular ultrasound was more informative of disease severity than repeat EDx and directed a muscle biopsy that showed an autophagic vacuolar myopathy and the novel identification of vacuoles in capillary endothelial cells. Although genetic testing is required for confirmation, in milder cases of X-linked myopathy with excessive autophagy, neuromuscular ultrasound may aid in diagnosis even when EDx findings are inconclusive.
    DOI:  https://doi.org/10.1097/CND.0000000000000500
  34. Life Sci. 2024 Aug 20. pii: S0024-3205(24)00588-5. [Epub ahead of print]355 122998
    Myocardial ischemia-reperfusion injury: The balance mechanism between mitophagy and NLRP3 inflammasome.
    Li Chen, Lin-Shen Mao, Jin-Yi Xue, Yu-Hong Jian, Zi-Wen Deng, Maryam Mazhar, Yuan Zou, Ping Liu, Ming-Tai Chen, Gang Luo, Meng-Nan Liu.
      Myocardial ischemia-reperfusion injury (MIRI) is an injury to cardiomyocytes due to restoration of blood flow after myocardial infarction (MI). It has recently gained much attention in clinical research with special emphasis on the roles of mitochondrial autophagy and inflammation. A mild inflammatory response promotes recovery of post-ischemic cardiomyocyte function and vascular regeneration, but a severe inflammatory response can cause irreversible and substantial cellular damage. Similarly, moderate mitochondrial autophagy can help inhibit excessive inflammation and protect cardiomyocytes. However, MIRI is aggravated when mitochondrial function is disrupted, such as inadequate clearance of damaged mitochondria or excessive activation of mitophagy. How to moderately control mitochondrial autophagy while promoting its balance with nucleotide-binding oligomerization structural domain receptor protein 3 (NLRP3) inflammasome activation is critical. In this paper, we reviewed the molecular mechanisms of mitochondrial autophagy and NLRP3 inflammasome, described the interaction between NLRP3 inflammasome and mitochondrial autophagy, and the effects of different signaling pathways and molecular proteins on MIRI, to provide a reference for future research.
    Keywords:  Inflammatory response; Mitochondrial autophagy; Myocardial ischemia-reperfusion injury; Nucleotide-binding oligomerization structural domain receptor protein 3; Signaling pathway
    DOI:  https://doi.org/10.1016/j.lfs.2024.122998
  35. Nat Struct Mol Biol. 2024 Aug 22.
    Structural basis for lipid transfer by the ATG2A-ATG9A complex.
    Yang Wang, Selma Dahmane, Rujuan Ti, Xinyi Mai, Lizhe Zhu, Lars-Anders Carlson, Goran Stjepanovic.
      Autophagy is characterized by the formation of double-membrane vesicles called autophagosomes. Autophagy-related proteins (ATGs) 2A and 9A have an essential role in autophagy by mediating lipid transfer and re-equilibration between membranes for autophagosome formation. Here we report the cryo-electron microscopy structures of human ATG2A in complex with WD-repeat protein interacting with phosphoinositides 4 (WIPI4) at 3.2 Å and the ATG2A-WIPI4-ATG9A complex at 7 Å global resolution. On the basis of molecular dynamics simulations, we propose a mechanism of lipid extraction from the donor membranes. Our analysis revealed 3:1 stoichiometry of the ATG9A-ATG2A complex, directly aligning the ATG9A lateral pore with ATG2A lipid transfer cavity, and an interaction of the ATG9A trimer with both the N-terminal and the C-terminal tip of rod-shaped ATG2A. Cryo-electron tomography of ATG2A liposome-binding states showed that ATG2A tethers lipid vesicles at different orientations. In summary, this study provides a molecular basis for the growth of the phagophore membrane and lends structural insights into spatially coupled lipid transport and re-equilibration during autophagosome formation.
    DOI:  https://doi.org/10.1038/s41594-024-01376-6
  36. Anal Chem. 2024 Aug 21.
    Tailoring the pKa of Fluorescence Lifetime Imaging Probes to Visualize Aggrephagy and Resolve Its Microenvironmental Viscosity.
    Yu Wei, Xiaochen Gao, Jiabao Fang, Yu Xiao, Jiachen Liu, Yu Liu, Xin Zhang, Baoxing Shen.
      Aggrephagy describes lysosomal transport and degradation of protein aggregates via cellular macroautophagy, a key mechanism to prevent neurodegenerative diseases. Here, we develop a dual-probe method to visualize the aggrephagy process and resolve its viscosity heterogeneity using fluorescence lifetime imaging (FLIM). The dual-probe system consists of (1) a near-infrared lysosomal targeting FLIM probe (Lyso-P1) that is derived from a rhodamine scaffold with a tailored pKa value to accommodate an acidic lysosomal environment and (2) a green BODIPY-based FLIM probe (Agg-P2) that reports on degradation of cellular aggregates via HaloTag. Both probes exhibit acid-resistant, viscosity-dependent fluorescence intensity and lifetime (τ) responses, which are ready for intensity- and FLIM-based imaging. Photochemical, theoretical, and biochemical characterizations reveal the probes' mechanism-of-actions. In cells, we exploit Lyso-P1 and Agg-P2 to simultaneously quantify both lysosomal and protein aggegates' viscosity changes upon the aggrephagy process via FLIM. We reveal orthogonal changes in microenvironmental viscosities and morphological heterogeneity upon various cellular stresses. Overall, we provide an imaging toolset to quantitatively study aggrephay, which may benefit screening of aggrephay modulators for disease intervention.
    DOI:  https://doi.org/10.1021/acs.analchem.4c02065
  37. Genes Dev. 2024 Aug 21.
    TFEB controls expression of human syncytins during cell-cell fusion.
    Meagan N Esbin, Liza Dahal, Vinson B Fan, Joey McKenna, Eric Yin, Xavier Darzacq, Robert Tjian.
      During human development, a temporary organ is formed, the placenta, which invades the uterine wall to support nutrient, oxygen, and waste exchange between the mother and fetus until birth. Most of the human placenta is formed by a syncytial villous structure lined by syncytialized trophoblasts, a specialized cell type that forms via cell-cell fusion of underlying progenitor cells. Genetic and functional studies have characterized the membrane protein fusogens Syncytin-1 and Syncytin-2, both of which are necessary and sufficient for human trophoblast cell-cell fusion. However, identification and characterization of upstream transcriptional regulators regulating their expression have been limited. Here, using CRISPR knockout in an in vitro cellular model of syncytiotrophoblast development (BeWo cells), we found that the transcription factor TFEB, mainly known as a regulator of autophagy and lysosomal biogenesis, is required for cell-cell fusion of syncytiotrophoblasts. TFEB translocates to the nucleus, exhibits increased chromatin interactions, and directly binds the Syncytin-1 and Syncytin-2 promoters to control their expression during differentiation. Although TFEB appears to play a critical role in syncytiotrophoblast differentiation, ablation of TFEB largely does not affect lysosomal gene expression or lysosomal biogenesis in differentiating BeWo cells, suggesting a previously uncharacterized role for TFEB in controlling the expression of human syncytins.
    Keywords:  TFEB; cell fusion; placenta; single-molecule imaging; syncytin; transcription factor
    DOI:  https://doi.org/10.1101/gad.351633.124
  38. Biochim Biophys Acta Mol Basis Dis. 2024 Aug 20. pii: S0925-4439(24)00472-1. [Epub ahead of print] 167478
    Npc1 deficiency impairs microglia function via TREM2-mTOR signaling in Niemann-Pick disease type C.
    Liang Qiao, Xiaojing Han, Ru Ding, Xiaodi Shang, Lulu Xiao, Ge Gao, Chu Zhang, Jing Kang, Xi Su, Yanli Liu, Jiankai Luo, Xin Yan, Juntang Lin.
      Niemann-Pick disease Type C (NPC) is a neurodegenerative disease mainly caused by the mutation in NPC1 gene, leading to massive accumulation of unesterified cholesterol in the late endosome/lysosome of cells. Impaired phenotype of microglia is a hallmark in Npc1 mutant mice (Npc1-/- mice). However, the mechanism of Npc1 in regulating microglial function is still unclear. Here, we showed that the reactive microglia in the neonatal Npc1-/- mice indicated by the increased lysosome protein CD68 and phagocytic activity were associated with disrupted TREM2-mTOR signaling in microglia. Furthermore, in Npc1-deficient BV2 cells, genetic deletion of Trem2 partially restored microglial function, probably via restored mTOR signaling. Taken together, our findings indicated that loss of Npc1 in microglia caused changes of their morphologies and the impairment of lysosomal function, which were linked to the TREM2-mTOR signaling pathway.
    Keywords:  Development; Microglia; Npc1; TREM2; mTOR
    DOI:  https://doi.org/10.1016/j.bbadis.2024.167478
  39. Int J Ophthalmol. 2024 ;17(8): 1531-1544
    NLRP3 and autophagy in retinal ganglion cell inflammation in age-related macular degeneration: potential therapeutic implications.
    Xiao-Li Wang, Yun-Xia Gao, Qiong-Zhen Yuan, Ming Zhang.
      Retinal degenerative diseases were a large group of diseases characterized by the primary death of retinal ganglion cells (RGCs). Recent studies had shown an interaction between autophagy and nucleotide-binding oligomerization domain-like receptor 3 (NLRP3) inflammasomes, which may affect RGCs in retinal degenerative diseases. The NLRP3 inflammasome was a protein complex that, upon activation, produces caspase-1, mediating the apoptosis of retinal cells and promoting the occurrence and development of retinal degenerative diseases. Upregulated autophagy could inhibit NLRP3 inflammasome activation, while inhibited autophagy can promote NLRP3 inflammasome activation, which leaded to the accelerated emergence of drusen and lipofuscin deposition under the neurosensory retina. The activated NLRP3 inflammasome could further inhibit autophagy, thus forming a vicious cycle that accelerated the damage and death of RGCs. This review discussed the relationship between NLRP3 inflammasome and autophagy and its effects on RGCs in age-related macular degeneration, providing a new perspective and direction for the treatment of retinal diseases.
    Keywords:  NLRP3 inflammasome; age-related macular degeneration; autophagy; retinal degeneration; retinal ganglion cells
    DOI:  https://doi.org/10.18240/ijo.2024.08.20
  40. J Gerontol A Biol Sci Med Sci. 2024 Aug 23. pii: glae204. [Epub ahead of print]
    Inhibition of OLR1 reduces SASP of nucleus pulposus cells by targeting autophagy-GATA4 axis.
    Jia-Wei Gao, Hang Shi, Fu-Ping Gao, Zhi-Min Zhou, Xin Peng, Rui Sun, V L F Cabral, Jian Li, Yun-Tao Wang, Xiao-Hu Wang, Xiao-Tao Wu.
      Targeting cellular senescence and Senescence Associated Secretory Phenotype (SASP) through autophagy has emerged as a promising intervertebral disc (IVD) degeneration (IDD) treatment strategy in recent years. This study aimed to clarify the role and mechanism of autophagy in preventing IVD SASP. Methods involved in vitro experiments with nucleus pulposus (NP) tissues from normal and IDD patients, as well as an in vivo IDD animal model. GATA4's regulatory role in SASP was validated both in vitro and in vivo, while autophagy modulators were employed to assess their impact on GATA4 and SASP. Transcriptomic sequencing identified Oxidized low-density lipoprotein receptor 1 (OLR1) as a key regulator of autophagy and GATA4. A series of experiments manipulated OLR1 expression to investigate associated effects. Results demonstrated significantly increased senescent NP cells (NPCs) and compromised autophagy in IDD patients and animal models, with SASP closely linked to IDD progression. The aged disc milieu impeded autophagic GATA4 degradation, leading to elevated SASP expression in senescent NPCs. Restoring autophagy reversed senescence by degrading GATA4, hence disrupting the SASP cascade. Moreover, OLR1 was identified for its regulation of autophagy and GATA4 in senescent NPCs. Silencing OLR1 enhanced autophagic activity, suppressing GATA4-induced senescence and SASP expression in senescent NPCs. In conclusion, OLR1 was found to control autophagy-GATA4 and SASP, with targeted OLR1 inhibition holding promise in alleviating GATA4-induced senescence and SASP expression while delaying extracellular matrix degradation, offering a novel therapeutic approach for IDD management.
    Keywords:  Autophagy; GATA4; Nucleus pulposus cells; OLR1; Senescence Associated Secretory Phenotype
    DOI:  https://doi.org/10.1093/gerona/glae204
  41. Sci Rep. 2024 08 16. 14(1): 18970
    Ferulic acid restores mitochondrial dynamics and autophagy via AMPK signaling pathway in a palmitate-induced hepatocyte model of metabolic syndrome.
    Yitong Li, Weiyang Zhao, Ali Tahir Sair, Tong Li, Rui Hai Liu.
      Mitochondrial dysfunction, characterized by elevated oxidative stress, impaired energy balance, and dysregulated mitochondrial dynamics, is a hallmark of metabolic syndrome (MetS) and its comorbidities. Ferulic acid (FA), a principal phenolic compound found in whole grains, has demonstrated potential in ameliorating oxidative stress and preserving energy homeostasis. However, the influence of FA on mitochondrial health within the context of MetS remains unexplored. Moreover, the impact of FA on autophagy, which is essential for maintaining energy homeostasis and mitochondrial integrity, is not fully understood. Here, we aimed to study the mechanisms of action of FA in regulating mitochondrial health and autophagy using palmitate-treated HepG2 hepatocytes as a MetS cell model. We found that FA improved mitochondrial health by restoring redox balance and optimizing mitochondrial dynamics, including biogenesis and the fusion/fission ratio. Additionally, FA was shown to recover autophagy and activate AMPK-related cell signaling. Our results provide new insights into the therapeutic potential of FA as a mitochondria-targeting agent for the prevention and treatment of MetS.
    Keywords:  Autophagy; Diabetes; Ferulic acid; Metabolic syndrome; Mitochondria; Obesity; Phenolics
    DOI:  https://doi.org/10.1038/s41598-024-66362-w
  42. Alzheimers Dement. 2024 Aug 22.
    Disrupted mitochondrial response to nutrients is a presymptomatic event in the cortex of the APPSAA knock-in mouse model of Alzheimer's disease.
    Andrés Norambuena, Vijay Kumar Sagar, Zhuoying Wang, Prakash Raut, Ziang Feng, Horst Wallrabe, Evelyn Pardo, Taylor Kim, Shagufta Rehman Alam, Song Hu, Ammasi Periasamy, George S Bloom.
       INTRODUCTION: Reduced brain energy metabolism, mammalian target of rapamycin (mTOR) dysregulation, and extracellular amyloid beta (Aβ) oligomer (xcAβO) buildup are some well-known Alzheimer's disease (AD) features; how they promote neurodegeneration is poorly understood. We previously reported that xcAβOs inhibit nutrient-induced mitochondrial activity (NiMA) in cultured neurons. We now report NiMA disruption in vivo.
    METHODS: Brain energy metabolism and oxygen consumption were recorded in heterozygous amyloid precursor protein knock-in (APPSAA) mice using two-photon fluorescence lifetime imaging and multiparametric photoacoustic microscopy.
    RESULTS: NiMA is inhibited in APPSAA mice before other defects are detected in these Aβ-producing animals that do not overexpress APP or contain foreign DNA inserts into genomic DNA. Glycogen synthase kinase 3 (GSK3β) signals through mTORC1 to regulate NiMA independently of mitochondrial biogenesis. Inhibition of GSK3β with TWS119 stimulates NiMA in cultured human neurons, and mitochondrial activity and oxygen consumption in APPSAA mice.
    DISCUSSION: NiMA disruption in vivo occurs before plaques, neuroinflammation, and cognitive decline in APPSAA mice, and may represent an early stage in human AD.
    HIGHLIGHTS: Amyloid beta blocks communication between lysosomes and mitochondria in vivo. Nutrient-induced mitochondrial activity (NiMA) is disrupted long before the appearance of Alzheimer's disease (AD) histopathology in heterozygous amyloid precursor protein knock-in (APPSAA/+) mice. NiMA is disrupted long before learning and memory deficits in APPSAA/+ mice. Pharmacological interventions can rescue AD-related NiMA disruption in vivo.
    Keywords:  amino acids; brain metabolism; insulin; mammalian target of rapamycin; tau
    DOI:  https://doi.org/10.1002/alz.14144
  43. Heliyon. 2024 Aug 15. 10(15): e35299
    Bibliometric analysis of lipophagy:2013 to 2023.
    Lu Zhao, Mengmeng Pang, Zhenyue Fu, Huaqin Wu, Qingqiao Song.
      Lipophagy is defined as the autophagic degradation of lipid droplets. It is a selective autophagy process that can continuously circulate and redistribute metabolites to maintain the body's energy balance. Over the last ten years, there has been a significant increase in the amount of literature on lipophagy, making it more challenging to track the field's advancement using conventional techniques. The data from the lipophagy literature published in the last ten years was converted into visual representations with the use of bibliometric tools. An increasing number of countries and institutions are delving further into lipophagy research with the support of visualization technologies. The five main illnesses of cancer, atherosclerosis, fatty liver, hyperlipidemia, and neurodegenerative diseases have become study opportunities, as have the mechanisms of macroautophagy, microautophagy, and chaperone-mediated autophagy.
    Keywords:  Atherosclerosis5; Bibliometric2; Cancer6; Fatty liver4; Lipid metabolism3; Lipophagy1
    DOI:  https://doi.org/10.1016/j.heliyon.2024.e35299
  44. CNS Neurosci Ther. 2024 Aug;30(8): e70006
    OTULIN's influence on neuroinflammation and pain modulation in trigeminal neuralgia.
    Haiyang Wang, Heng Wang, Wenhao Zheng, Ding Wang, Chenglong Sun, Jun Dong, Wenhua Yu, Quan Du.
       INTRODUCTION: Trigeminal neuralgia (TN), marked by chronic pain from neural damage, is closely associated with inflammation. The role of OTULIN, a key regulator in inflammation and autophagy, is not fully understood in TN. The regulatory mechanism of OTULIN, a key protein involved in modulating inflammatory responses and autophagy processes, remains incompletely elucidated, particularly in the context of TN and neuroinflammation.
    METHODS: An infraorbital nerve ligation-induced rat model of TN was used. OTULIN's expression was modulated using adenovirus vectors and short hairpin RNA. The impact on pain and inflammatory responses was assessed via quantitative real-time polymerase chain reaction, western blot, immunofluorescence, and transcriptomic analysis.
    RESULTS: Enhanced OTULIN expression significantly increased head withdrawal thresholds and reduced pain sensitivity and neuroinflammatory markers in the model. Conversely, silencing OTULIN exacerbated pain and inflammation. Transcriptomic data revealed OTULINs influence on both inflammatory and autophagy pathways, specifically in suppressing NLR family pyrin domain containing 3 (NLRP3) inflammasome and promoting autophagy. In vitro experiments demonstrated OTULIN's inhibition of inflammatory markers in microglia and neurons.
    CONCLUSION: OTULIN is crucial in modulating TN, reducing neuropathic pain and neuroinflammation by activating the autophagy pathway and inhibiting the NLRP3 inflammasome.
    Keywords:  IONL model; NLRP3 inflammasome; OTULIN; autophagy; inflammatory markers; neuropathic pain; treatment strategies; trigeminal neuralgia
    DOI:  https://doi.org/10.1111/cns.70006
  45. Discov Oncol. 2024 Aug 18. 15(1): 358
    Pediatric cancer-pathology and microenvironment influence: a perspective into osteosarcoma and non-osteogenic mesenchymal malignant neoplasms.
    Consolato M Sergi.
      Pediatric cancer remains the leading cause of disease-related death among children aged 1-14 years. A few risk factors have been conclusively identified, including exposure to pesticides, high-dose radiation, and specific genetic syndromes, but the etiology underlying most events remains unknown. The tumor microenvironment (TME) includes stromal cells, vasculature, fibroblasts, adipocytes, and different subsets of immunological cells. TME plays a crucial role in carcinogenesis, cancer formation, progression, dissemination, and resistance to therapy. Moreover, autophagy seems to be a vital regulator of the TME and controls tumor immunity. Autophagy is an evolutionarily conserved intracellular process. It enables the degradation and recycling of long-lived large molecules or damaged organelles using the lysosomal-mediated pathway. The multifaceted role of autophagy in the complicated neoplastic TME may depend on a specific context. Autophagy may function as a tumor-suppressive mechanism during early tumorigenesis by eliminating unhealthy intracellular components and proteins, regulating antigen presentation to and by immune cells, and supporting anti-cancer immune response. On the other hand, dysregulation of autophagy may contribute to tumor progression by promoting genome damage and instability. This perspective provides an assortment of regulatory substances that influence the features of the TME and the metastasis process. Mesenchymal cells in bone and soft-tissue sarcomas and their signaling pathways play a more critical role than epithelial cells in childhood and youth. The investigation of the TME in pediatric malignancies remains uncharted primarily, and this unique collection may help to include novel advances in this setting.
    Keywords:  Epithelial-to-mesenchymal transition; Mesenchymal-to-epithelial transition; Tumor microenvironment
    DOI:  https://doi.org/10.1007/s12672-024-01240-5
  46. Mol Metab. 2024 Aug 16. pii: S2212-8778(24)00143-1. [Epub ahead of print] 102012
    Mitochondrial protein deacetylation by SIRT3 in osteoclasts promotes bone resorption with aging in female mice.
    Kimberly K Richardson, Gareeballah Osman Adam, Wen Ling, Aaron Warren, Adriana Marques-Carvalho, Jeff D Thostenson, Kimberly Krager, Nukhet Aykin-Burns, Stephanie D Byrum, Maria Almeida, Ha-Neui Kim.
       OBJECTIVES: The mitochondrial deacetylase sirtuin-3 (SIRT3) is necessary for the increased bone resorption and enhanced function of mitochondria in osteoclasts that occur with advancing age; how SIRT3 drives bone resorption remains elusive.
    METHODS: To determine the role of SIRT3 in osteoclast mitochondria, we used mice with conditional loss of Sirt3 in osteoclast lineage and mice with germline deletion of either Sirt3 or its known target Pink1.
    RESULTS: SIRT3 stimulates mitochondrial quality in osteoclasts in a PINK1-independent manner, promoting mitochondrial activity and osteoclast maturation and function, thereby contributing to bone loss in female but not male mice. Quantitative analyses of global proteomes and acetylomes revealed that deletion of Sirt3 dramatically increased acetylation of osteoclast mitochondrial proteins, particularly ATPase inhibitory factor 1 (ATPIF1), an essential protein for mitophagy. Inhibition of mitophagy via mdivi-1 recapitulated the effect of deletion of Sirt3 or Atpif1 in osteoclast formation and mitochondrial function.
    CONCLUSIONS: Decreasing mitophagic flux in osteoclasts may be a promising pharmacotherapeutic approach to treat osteoporosis in older adults.
    Keywords:  Acetylation; Aging; Mitochondria; Osteoclasts; Proteomics; SIRT3
    DOI:  https://doi.org/10.1016/j.molmet.2024.102012
  47. Nature. 2024 Aug 21.
    Lysosomes drive the piecemeal removal of mitochondrial inner membrane.
    Akriti Prashar, Claudio Bussi, Antony Fearns, Mariana I Capurro, Xiaodong Gao, Hiromi Sesaki, Maximiliano G Gutierrez, Nicola L Jones.
      Mitochondrial membranes define distinct structural and functional compartments. Cristae of the inner mitochondrial membrane (IMM) function as independent bioenergetic units that undergo rapid and transient remodelling, but the significance of this compartmentalized organization is unknown1. Using super-resolution microscopy, here we show that cytosolic IMM vesicles, devoid of outer mitochondrial membrane or mitochondrial matrix, are formed during resting state. These vesicles derived from the IMM (VDIMs) are formed by IMM herniation through pores formed by voltage-dependent anion channel 1 in the outer mitochondrial membrane. Live-cell imaging showed that lysosomes in proximity to mitochondria engulfed the herniating IMM and, aided by the endosomal sorting complex required for transport machinery, led to the formation of VDIMs in a microautophagy-like process, sparing the remainder of the organelle. VDIM formation was enhanced in mitochondria undergoing oxidative stress, suggesting their potential role in maintenance of mitochondrial function. Furthermore, the formation of VDIMs required calcium release by the reactive oxygen species-activated, lysosomal calcium channel, transient receptor potential mucolipin 1, showing an interorganelle communication pathway for maintenance of mitochondrial homeostasis. Thus, IMM compartmentalization could allow for the selective removal of damaged IMM sections via VDIMs, which should protect mitochondria from localized injury. Our findings show a new pathway of intramitochondrial quality control.
    DOI:  https://doi.org/10.1038/s41586-024-07835-w
  48. Cell Signal. 2024 Aug 17. pii: S0898-6568(24)00319-X. [Epub ahead of print] 111351
    Early treatment with 2-deoxy-d-glucose reduces proliferative proteins in the kidney and slows cyst growth in a hypomorphic Pkd1 mouse model of autosomal dominant polycystic kidney disease (PKD).
    Daniel Atwood, Zhibin He, Makoto Miyazaki, Frehiwet Hailu, Jelena Klawitter, Charles L Edelstein.
      In autosomal dominant polycystic kidney disease (ADPKD) there is cyst growth in the kidneys that leads to chronic kidney disease often requiring dialysis or kidney transplantation. There is enhanced aerobic glycolysis (Warburg effect) in the cyst lining epithelial cells that contributes to cyst growth. The glucose mimetic, 2-Deoxy-d-glucose (2-DG) inhibits glycolysis. The effect of early and late administration of 2-DG on cyst growth and kidney function was determined in Pkd1RC/RC mice, a hypomorphic PKD model orthologous to human disease. Early administration of 2-DG resulted in decreased kidney weight, cyst index, cyst number and cyst size, but no change in kidney function. 2-DG decreased proliferation. a major mediator of cyst growth, of cells lining the cyst. Late administration of 2-DG did not have an effect on cyst growth or kidney function. To determine mechanisms of decreased proliferation, an array of mTOR and autophagy proteins was measured in the kidney. 2-DG suppressed autophagic flux in Pkd1RC/RC kidneys and decreased autophagy proteins, ATG3, ATG5 and ATG12-5. 2-DG had no effect on p-mTOR or p-S6 (mTORC1) and decreased p-AMPK. 2-DG decreased p-4E-BP1, p-c-Myc and p-ERK that are known to promote proliferation and cyst growth in PKD. 2-DG decreased p-AKTS473, a marker of mTORC2. So the role of mTORC2 in cyst growth was determined. Knockout of Rictor (mTORC2) in Pkd1 knockout mice did not change the PKD phenotype. In summary, 2-DG decreases proliferation in cells lining the cyst and decreases cyst growth by decreasing proteins that are known to promote proliferation. In conclusion, the present study reinforces the therapeutic potential of 2-DG for use in patients with ADPKD.
    Keywords:  Apoptosis; Autophagy; Kidney; Polycystic; Proliferation
    DOI:  https://doi.org/10.1016/j.cellsig.2024.111351
  49. Free Radic Biol Med. 2024 Aug 14. pii: S0891-5849(24)00601-4. [Epub ahead of print]224 9-22
    Knocking down EGR1 inhibits nucleus pulposus cell senescence and mitochondrial damage through activation of PINK1-Parkin dependent mitophagy, thereby delaying intervertebral disc degeneration.
    Zuo-Long Wu, Ke-Ping Wang, Ya-Jun Chen, Wei Song, Yong Liu, Kai-Sheng Zhou, Peng Mao, Zhong Ma, Hai-Hong Zhang.
      Mitophagy plays a crucial role in maintaining the homeostasis of intervertebral disc (IVD). Early Growth Response 1 (EGR1), a conservative transcription factor, is commonly upregulated under oxidative stress conditions and participates in regulating cellular senescence, apoptosis, and inflammatory responses. However, the specific role of EGR1 in nucleus pulposus (NP) cell senescence and mitophagy remains unclear. In this study, through bioinformatics analysis and validation using human tissue specimens, we found that EGR1 is significantly upregulated in IVD degeneration (IDD). Further experimental results demonstrate that knockdown of EGR1 inhibits TBHP-induced NP cell senescence and mitochondrial dysfunction while promoting the activation of mitophagy. The protective effect of EGR1 knockdown on NP cell senescence and mitochondrion disappears upon inhibition of mitophagy with mdivi1. Mechanistic studies reveal that EGR1 suppresses NP cell senescence and mitochondrial dysfunction by modulating the PINK1-Parkin dependent mitophagy pathway. Additionally, EGR1 knockdown delays acupuncture-induced IDD in rats. In conclusion, our study demonstrates that under TBHP-induced oxidative stress, EGR1 knockdown mitigates NP cell senescence and mitochondrial dysfunction through the PINK1-Parkin dependent mitophagy pathway, thereby alleviating IDD.
    Keywords:  Cell senescence; EGR1; IDD; Mitophagy; Oxidative stress; PINK1; Parkin
    DOI:  https://doi.org/10.1016/j.freeradbiomed.2024.08.015
  50. Cell Prolif. 2024 Aug 18. e13728
    Mechanical stress-induced autophagy is cytoskeleton dependent.
    Lin Liu, Wei Zheng, Yuhui Wei, Qian Li, Nan Chen, Qinglin Xia, Lihua Wang, Jun Hu, Xingfei Zhou, Yanhong Sun, Bin Li.
      The cytoskeleton is essential for mechanical signal transduction and autophagy. However, few studies have directly demonstrated the contribution of the cytoskeleton to mechanical stress-induced autophagy. We explored the role of the cytoskeleton in response to compressive force-induced autophagy in human cell lines. Inhibition and activation of cytoskeletal polymerization using small chemical molecules revealed that cytoskeletal microfilaments are required for changes in the number of autophagosomes, whereas microtubules play an auxiliary role in mechanical stress-induced autophagy. The intrinsic mechanical properties and special intracellular distribution of microfilaments may account for a large proportion of compression-induced autophagy. Our experimental data support that microfilaments are core components of mechanotransduction signals.
    DOI:  https://doi.org/10.1111/cpr.13728
  51. Theriogenology. 2024 Aug 16. pii: S0093-691X(24)00340-6. [Epub ahead of print]229 100-107
    MiR-302c-3p regulates autophagy and apoptosis in ovarian granulosa cells via the LATS2/YAP axis in chickens.
    Peng Ren, Kejun Wu, Meiying Chen, Qinke Huang, Zhengwei Luo, Ye Wang.
      The degenerative process of follicular atresia in hens naturally commences in granulosa cells, significantly impacting laying hens' reproductive performance. Past studies suggested that granulosa cell autophagy and apoptosis work together to cause follicular atresia. Recent research indicates that miRNA regulates granulosa autophagy and apoptosis, which contributes to the development of follicular atresia. However, the role of miR-302c-3p in follicular atresia and development remains unclear. In this study with the RNA-seq approach, we found that miR-302c-3p expression was significantly decreased in atrophic follicles, suggesting its involvement in the follicular atresia process. Following this, we performed in vitro studies to confirm that miR-302c-3p inhibits autophagy and apoptosis in chicken granulosa cells. Mechanistically, LATS2 is considered as the putative target gene of miR-302c-3p, and it has been demonstrated that LATS2 exerts a positive regulatory role in the modulation of autophagy and apoptosis in chicken granulosa cells. Furthermore, we verified the regulatory function of miR-302c-3p in chicken granulosa cells via the LATS2-YAP signaling pathway. Our results collectively demonstrates that miR-302c-3p targets LATS2 to modulate the YAP signaling pathway, impacting autophagy and apoptosis in granulosa cells leading to follicular atresia.
    Keywords:  Apoptosis; Autophagy; LATS2; YAP pathway; miR-302c-3p
    DOI:  https://doi.org/10.1016/j.theriogenology.2024.08.020
  52. Biotech Histochem. 2024 Aug 22. 1-18
    Hesperetin regulates PI3K/Akt and mTOR pathways to exhibit its antiproliferative effect against colon cancer cells.
    Gowrikumar Saiprasad, Palanivel Chitra, Ramar Manikandan, Arunagirinathan Koodalingam, Ganaspasam Sudhandiran.
      Hesperetin, a citrus flavonoid, has been a widely studied anticancer agent against many types of cancers, but the exact mechanism of efficacy is still unrevealed. Therefore, this study has attempted to delineate the mechanical aspect of hesperetin's anticancer efficacy against colon cancer using immunoblotting, scanning, and transmission electron microscopic studies. The treatment with hesperetin (25 and 50 µM) has significantly (p < 0.0001) curbed down the proliferation and cell viability of HCT-15 cells in a concentration as well as time dependent manner. Hesperetin was able to achieve this through the induction of caspase-dependent apoptosis. Moreover, hesperetin effectively inhibited phosphorylation of Akt with a parallel increase in PTEN expression thereby inhibiting the PI3K signaling axis, which contributes to the suppression of proliferation. In addition, hesperetin enhanced autophagy through dephosphorylating mTOR, one of the downstream targets of Akt with simultaneous acceleration in Beclin-1 and LC3-II expression levels. Interestingly, hesperetin enhanced the effects of Akt inhibitor LY294002 and mTOR inhibitor rapamycin. This study documented the potential of hesperetin to induce apoptosis through simultaneous acceleration over the autophagic process in colon cancer cells. Thus, hesperetin played a beneficial therapeutic role in preventing colon carcinoma growth by regulating the Akt and mTOR signaling axis.
    Keywords:  Autophagy; colon cancer; flavonoid; hesperetin; mTOR apoptosis
    DOI:  https://doi.org/10.1080/10520295.2024.2382764
  53. World J Gastrointest Oncol. 2024 Aug 15. 16(8): 3376-3381
    Navigating the labyrinth of long non-coding RNAs in colorectal cancer: From chemoresistance to autophagy.
    Jia-Mei Yu, Chong-Qi Sun, Huan-Huan Xu, Ya-Li Jiang, Xing-Yu Jiang, Si-Qi Ni, Ting-Yu Zhao, Ling-Xiang Liu.
      Long non-coding RNAs (lncRNAs), with transcript lengths exceeding 200 nucleotides and little or no protein-coding capacity, have been found to impact colorectal cancer (CRC) through various biological processes. LncRNA expression can regulate autophagy, which plays dual roles in the initiation and progression of cancers, including CRC. Abnormal expression of lncRNAs is associated with the emergence of chemoresistance. Moreover, it has been confirmed that targeting autophagy through lncRNA regulation could be a viable approach for combating chemoresistance. Two recent studies titled "Human β-defensin-1 affects the mammalian target of rapamycin pathway and autophagy in colon cancer cells through long non-coding RNA TCONS_00014506" and "Upregulated lncRNA PRNT promotes progression and oxaliplatin resistance of colorectal cancer cells by regulating HIPK2 transcription" revealed novel insights into lncRNAs associated with autophagy and oxaliplatin resistance in CRC, respectively. In this editorial, we particularly focus on the regulatory role of lncRNAs in CRC-related autophagy and chemoresistance since the regulation of chemotherapeutic sensitivity by intervening with the lncRNAs involved in the autophagy process has become a promising new approach for cancer treatment.
    Keywords:  Autophagy; Chemoresistance; Colorectal cancer; Long non-coding RNA; Oxaliplatin
    DOI:  https://doi.org/10.4251/wjgo.v16.i8.3376
  54. Insect Biochem Mol Biol. 2024 Aug 19. pii: S0965-1748(24)00107-3. [Epub ahead of print] 104176
    Notch signaling promotes differentiation, cell death and autophagy in Drosophila hematopoietic system.
    Fangzhou Luo, Chengcheng Zhang, Zhengqi Shi, Tong Mao, Li Hua Jin.
      Notch signaling is a highly conserved pathway between mammals and Drosophila and plays a key role in various biological processes. Drosophila has emerged as a powerful model for studying hematopoiesis and leukemia. In exception to crystal cells, the strength of Notch signaling in Drosophila lymph gland cortical zone (CZ) / intermediate zone (IZ) cells is weak. However, the influence of Notch activation in the lymph gland CZ/IZ cells and circulating hemocytes on hematopoietic homeostasis maintenance is unclear. Here, we showed that Notch activation in lymph gland CZ/IZ cells induced overdifferentiation of progenitors. Moreover, Notch activation promoted lamellocyte generation via NFκB/Toll signaling activation and increased reactive oxygen species (ROS). In addition, we found that Notch activation in lymph gland CZ/IZ cells and circulating hemocytes caused caspase-independent and nonautophagic cell death. However, crystal cell autophagy was activated by upregulation of the expression of the target gene of the Hippo/Yki pathway Diap1. Moreover, we showed that Notch activation could alleviate cytokine storms and improve the survival of Rasv12 leukemia model flies. Our study revealed the various mechanisms of hematopoietic dysregulation induced by Notch activation in healthy flies and the therapeutic effect of Notch activation on leukemia model flies.
    Keywords:  Drosophila; Notch signaling; autophagy; cell death; hematopoiesis; leukemia
    DOI:  https://doi.org/10.1016/j.ibmb.2024.104176
  55. Toxicol In Vitro. 2024 Aug 16. pii: S0887-2333(24)00149-8. [Epub ahead of print]100 105919
    Isobavachin induces autophagy-mediated cytotoxicity in AML12 cells via AMPK and PI3K/Akt/mTOR pathways.
    Ning Xia, Qing-Hai Chen, Zhao-Jun Meng, Shu-Yue Ma, Jia-Li Huang, Rong Shen, Yu-Tong Dong, Hai-Wei Du, Kun Zhou.
      Isobavachin (IBA) is a dihydroflavonoid compound with various pharmacological effects. However, further investigation into the hepatotoxicity of IBA is necessary. This study aims to identify the hepatotoxic effects of IBA and explore its potential mechanisms. The study assessed the impact of IBA on the viability of AML12, HepG2, LO2, rat, and mouse primary hepatocytes using MTT and LDH assays. Autophagy was detected in AML12 cells after IBA treatment using electron microscopy, MDC, and Ad-mCherry-GFP-LC3B fluorescence. The effect of IBA on autophagy-related proteins was examined using Western blot. The results showed that IBA had dose-dependent inhibitory effects on five cells, induced autophagy in AML12 cells, and promoted autophagic flux. The study found that IBA treatment inhibited phosphorylation of PI3K, Akt, and mTOR, while increasing phosphorylation levels of AMPK and ULK1. Treatment with both AMPK and PI3K inhibitors reversed the expression of AMPK and PI3K-Akt-mTOR signaling pathway proteins. These results suggest that IBA may have hepatocytotoxic effects but can also prevent IBA hepatotoxicity by inhibiting the AMPK and PI3K/Akt/mTOR signaling pathways. This provides a theoretical basis for preventing and treating IBA hepatotoxicity in clinical settings.
    Keywords:  AMPK; Autophagy; Hepatotoxicity; Isobavachin; PI3K
    DOI:  https://doi.org/10.1016/j.tiv.2024.105919
  56. Elife. 2024 Aug 19. pii: e97027. [Epub ahead of print]13
    Iron-sulfur cluster loss in mitochondrial CISD1 mediates PINK1 loss-of-function phenotypes.
    Sara Bitar, Timo Baumann, Christopher Weber, Majd Abusaada, Liliana Rojas-Charry, Patrick Ziegler, Thomas Schettgen, Isabella Eva Randerath, Vivek Venkataramani, Bernhard Michalke, Eva-Maria Hanschmann, Giuseppe Arena, Rejko Krueger, Li Zhang, Axel Methner.
      Parkinson's disease (PD) is characterized by the progressive loss of dopaminergic neurons in the substantia nigra of the midbrain. Familial cases of PD are often caused by mutations of PTEN-induced kinase 1 (PINK1) and the ubiquitin ligase Parkin, both pivotal in maintaining mitochondrial quality control. CISD1, a homodimeric mitochondrial iron-sulfur-binding protein, is a major target of Parkin-mediated ubiquitination. We here discovered a heightened propensity of CISD1 to form dimers in Pink1 mutant flies and in dopaminergic neurons from PINK1 mutation patients. The dimer consists of two monomers that are covalently linked by a disulfide bridge. In this conformation CISD1 cannot coordinate the iron-sulfur cofactor. Overexpressing Cisd, the Drosophila orthologue of CISD1, and a mutant Cisd incapable of binding the iron-sulfur cluster in Drosophila reduced climbing ability and lifespan. This was more pronounced with mutant Cisd and aggravated in Pink1 mutant flies. Complete loss of Cisd, in contrast, rescued all detrimental effects of Pink1 mutation on climbing ability, wing posture, dopamine levels, lifespan, and mitochondrial ultrastructure. Our results suggest that Cisd, probably iron-depleted Cisd, operates downstream of Pink1 shedding light on PD pathophysiology and implicating CISD1 as a potential therapeutic target.
    Keywords:  D. melanogaster; cell biology; human; mouse; neuroscience
    DOI:  https://doi.org/10.7554/eLife.97027
  57. Cell Mol Biol Lett. 2024 Aug 17. 29(1): 110
    PTBP1 knockdown impairs autophagy flux and inhibits gastric cancer progression through TXNIP-mediated oxidative stress.
    Shimin Wang, Xiaolin Wang, Changhong Qin, Ce Liang, Wei Li, Ai Ran, Qiang Ma, Xiaojuan Pan, Feifei Yang, Junwu Ren, Bo Huang, Yuying Liu, Yuying Zhang, Haiping Li, Hao Ning, Yan Jiang, Bin Xiao.
       BACKGROUND: Gastric cancer (GC) is a prevalent malignant tumor, and the RNA-binding protein polypyrimidine tract-binding protein 1 (PTBP1) has been identified as a crucial factor in various tumor types. Moreover, abnormal autophagy levels have been shown to significantly impact tumorigenesis and progression. Despite this, the precise regulatory mechanism of PTBP1 in autophagy regulation in GC remains poorly understood.
    METHODS: To assess the expression of PTBP1 in GC, we employed a comprehensive approach utilizing western blot, real-time quantitative polymerase chain reaction (RT-qPCR), and bioinformatics analysis. To further identify the downstream target genes that bind to PTBP1 in GC cells, we utilized RNA immunoprecipitation coupled with sequencing (si-PTBP1 RNA-seq). To evaluate the impact of PTBP1 on gastric carcinogenesis, we conducted CCK-8 assays, colony formation assays, and GC xenograft mouse model assays. Additionally, we utilized a transmission electron microscope, immunofluorescence, flow cytometry, western blot, RT-qPCR, and GC xenograft mouse model experiments to elucidate the specific mechanism underlying PTBP1's regulation of autophagy in GC.
    RESULTS: Our findings indicated that PTBP1 was significantly overexpressed in GC tissues compared with adjacent normal tissues. Silencing PTBP1 resulted in abnormal accumulation of autophagosomes, thereby inhibiting GC cell viability both in vitro and in vivo. Mechanistically, interference with PTBP1 promoted the stability of thioredoxin-interacting protein (TXNIP) mRNA, leading to increased TXNIP-mediated oxidative stress. Consequently, this impaired lysosomal function, ultimately resulting in blockage of autophagic flux. Furthermore, our results suggested that interference with PTBP1 enhanced the antitumor effects of chloroquine, both in vitro and in vivo.
    CONCLUSION: PTBP1 knockdown impairs GC progression by directly binding to TXNIP mRNA and promoting its expression. Based on these results, PTBP1 emerges as a promising therapeutic target for GC.
    Keywords:  Autophagy; Chloroquine; GC; PTBP1; TXNIP
    DOI:  https://doi.org/10.1186/s11658-024-00626-1
  58. Am J Reprod Immunol. 2024 Aug;92(2): e13903
    Spatial Activation of Autophagy in Human Placenta-Related Tissue During Labor: A Possible Mechanism for Labor Onset.
    Jing Shang, Zhijian Wang, Yingying Huang, Yuyu Wu, Jin Jin.
       INTRODUCTION: To explore the mechanisms of labor by investigating the autophagy of placental and fetal membranes tissue in normal pregnant women.
    METHODS: Placenta and fetal membranes were collected from women with singleton pregnancies without any medical complications and from women who delivered vaginally (labor-initiated group; L group) or by caesarean section (labor-noninitiated group; NL group). Autophagosomes were observed by transmission electron microscopy (TEM). Immunofluorescence and western blotting (WB) were used to detect protein levels of the autophagy markers LC3A and LC3B. TEM, immunohistochemistry (IHC), and WB were used to compare autophagy in different parts of the placenta and fetal membranes in the L and NL groups. The expression of LC3B/LC3A, ROCK1, and ROCK2 in the placenta of nonpregnant and pregnant rats was detected by WB and IHC.
    RESULTS: TEM and IHC results showed an increase in the number of autophagosomes and autophagic lysosomes in the L group, and WB results indicated an increase in the LC3B/A ratio between the placenta and fetal membranes in the L group. Autophagy was significantly increased on the maternal side of the placenta in the L group, and the level of autophagy became higher near rupture in the fetal membranes and near the point where the umbilical cord joins the placenta in the L group. The LC3B/A ratio increased and ROCK1 and ROCK2 levels decreased in postnatal rats.
    DISCUSSION: Autophagy can occur in the placenta and fetal membranes and its activity is higher at the onset of labor, suggesting a role in labor.
    Keywords:  autophagy; fetal membrane; labor; placenta
    DOI:  https://doi.org/10.1111/aji.13903
  59. Exp Clin Endocrinol Diabetes. 2024 Aug 21.
    Dihydromyricetin improves high glucose induced dopaminergic neuronal damage by activating AMPK-autophagy signaling pathway.
    Qi Li, Zhenjiang Song, Liting Peng, Shuidong Feng, Kebin Zhan, Hongyan Ling.
      In recent years, a growing number of clinical and biological studies have shown that patients with type 2 diabetes mellitus (T2DM) are at increased risk of developing Parkinson's disease (PD). Prolonged exposure to hyperglycemia results in abnormal glucose metabolism, which in turn cause pathological changes similar to PD, leading to selective loss of dopaminergic neurons in the compact part of substantia nigra. Dihydromyricetin (DHM) is a naturally occurring flavonoid with various biological activities including antioxidant and hepatoprotective properties. The aim of this study was to investigate whether DHM modulates high glucose-induced dopaminergic neuronal damage and its mechanism. We found that DHM ameliorated high glucose-induced dopaminergic neuronal damage and autophagy injury. Inhibition of autophagy by 3-methyladenine (3-MA) abrogated the beneficial effects of DHM on high glucose-induced dopaminergic neuronal damage. In addition, DHM increased levels of p-AMPK and p-ULK1. The AMPK inhibitor Compound C (CC) eliminated DHM-induced autophagy and subsequently inhibited the ameliorative effects of DHM on high glucose-induced dopaminergic neuronal damage. Taken together, DHM ameliorate high glucose-induced dopaminergic neuronal damage by activating AMPK-autophagy pathway.
    DOI:  https://doi.org/10.1055/a-2399-1174
  60. Adv Sci (Weinh). 2024 Aug;11(31): e2308307
    Aloperine Suppresses Cancer Progression by Interacting with VPS4A to Inhibit Autophagosome-lysosome Fusion in NSCLC.
    Weina Guo, Haifeng Zhou, Jingbo Wang, Junjie Lu, Yalan Dong, Zhenyu Kang, Xiaoyuan Qiu, Xiaohu Ouyang, Qianyun Chen, Junyi Li, Xiang Cheng, Keye Du, Mingyue Li, Zhihao Lin, Min Jin, Lei Zhang, Alexey Sarapultsev, Kuangyu Shi, Fangfei Li, Ge Zhang, Kongming Wu, Yueguang Rong, Vigo Heissmeyer, Yue Liu, Yunlun Li, Kun Huang, Shanshan Luo, Desheng Hu.
      Aloperine (ALO), a quinolizidine-type alkaloid isolated from a natural Chinese herb, has shown promising antitumor effects. Nevertheless, its common mechanism of action and specific target remain elusive. Here, it is demonstrated that ALO inhibits the proliferation and migration of non-small cell lung cancer cell lines in vitro and the tumor development in several mouse tumor models in vivo. Mechanistically, ALO inhibits the fusion of autophagosomes with lysosomes and the autophagic flux, leading to the accumulation of sequestosome-1 (SQSTM1) and production of reactive oxygen species (ROS), thereby inducing tumor cell apoptosis and preventing tumor growth. Knockdown of SQSTM1 in cells inhibits ROS production and reverses ALO-induced cell apoptosis. Furthermore, VPS4A is identified as a direct target of ALO, and the amino acids F153 and D263 of VPS4A are confirmed as the binding sites for ALO. Knockout of VPS4A in H1299 cells demonstrates a similar biological effect as ALO treatment. Additionally, ALO enhances the efficacy of the anti-PD-L1/TGF-β bispecific antibody in inhibiting LLC-derived subcutaneous tumor models. Thus, ALO is first identified as a novel late-stage autophagy inhibitor that triggers tumor cell death by targeting VPS4A.
    Keywords:  VPS4A; apoptosis; autophagy inhibition; non‐small cell lung cancer; sequestosome‐1
    DOI:  https://doi.org/10.1002/advs.202308307
  61. Am J Med Sci. 2024 Aug 16. pii: S0002-9629(24)01403-4. [Epub ahead of print]
    FOXO4 suppresses cisplatin resistance of Triple-Negative Breast Cancer by inhibiting autophagy.
    Yating Zhu, Chenguang Zhang, Qiuyu Yin, Wenting Xu, Yulou Luo, Jianghua Ou.
       BACKGROUND: Resistance to chemotherapy containing cisplatin (DDP) is a main challenge in the treatment of triple-negative breast cancer (TNBC). Forkhead box O4 (FOXO4) is frequently downregulated in DDP-resistant cells. However, it is unclear whether FOXO4 down-regulation is related to DDP resistance. Here, we investigated the relationship between FOXO4 and DDP resistance in TNBC.
    METHODS: We established the DDP-resistant cell lines MDA-MB-231/DDP and BT-549/DDP through in vitro selection. CCK-8 and colony formation assays analyzed cell growth. The resistance index was calculated. Cell autophagy was evaluated. Western blotting and qRT-PCR measured protein and gene expression. The binding between FOXO4 and TGF-β1 was determined by the dual-luciferase reporter assay.
    RESULTS: FOXO4 expression was significantly lower in MDA-MB-231/DDP and BT-549/DDP cells. FOXO4 overexpression increased the sensitivity of TNBC cells to DDP. The PI3K class Ⅲ and Beclin-1 levels and LC3-II/LC3-I ratio elevated significantly in DDP-resistant cells. Moreover, the autophagic flux was enhanced in DDP-resistant cells. 3-MA enhanced the sensitivity of TNBC cells to DDP by inhibiting autophagy. Overexpression of FOXO4, treatment with 3-MA, and their combination significantly reduced the drug resistance index. FOXO4 directly targeted TGF-β1. Additionally, TGF-β1 knockdown inhibited autophagy and restored the sensitivity of DDP-resistant cells to DDP. Mechanistically, FOXO4 affected TNBC resistance to DDP by regulating autophagy and TGF-β1.
    CONCLUSION: FOXO4 overexpression, in combination with autophagy inhibitors, can significantly improve the sensitivity of TNBC-resistant cells to DDP. These findings reveal the role and mechanism of FOXO4 in DDP sensitivity and may provide evidence for the development of TNBC therapies.
    Keywords:  FOXO4; TGF-β1; autophagy; cisplatin resistance; triple-negative breast cancer
    DOI:  https://doi.org/10.1016/j.amjms.2024.08.012
  62. Anal Chem. 2024 Aug 22.
    Mitochondria-Specific Fluorescent Probe for Revealing the Interaction between Mitochondria and Lysosomes during Apoptosis.
    Guofang Li, Hua Zheng, Langdi Zhang, Ling Huang, Weiying Lin.
      The mitochondria, as one of the essential organelles in cells, are closely associated with numerous biological processes. Therefore, the realization of clear and real-time imaging for tracking mitochondria is of profound significance. Here, we present a mitochondria-targeting fluorescent probe, N(CH2)3-PD-NEt, for the real-time fluorescence imaging of mitochondria in living cells. Using the probe, the fluorescence changes of mitochondria stimulated by different drugs were successfully observed by fluorescence imaging. In addition, the dynamic processes of mitochondria and lysosomes during apoptosis were also explored. Importantly, we observed several novel dynamic interaction patterns between mitochondria and lysosomes. Among them, the most prominent pattern involved the noncontact movements of two lysosomes, that is, one lysosome gradually approached the other lysosome over time, eventually coming into contact and merging with it while gradually combining with mitochondria to form new mitochondria. Notably, the protrusions of the mitochondria became increasingly evident during this process. Meanwhile, we successfully observed the dynamic changes of mitochondria with SIM super-resolution imaging. The study provides promising help for the in-depth study of the dynamic processes of mitochondrial physiology and pathology and the study of the interactions between organelles.
    DOI:  https://doi.org/10.1021/acs.analchem.4c03273
  63. Biochim Biophys Acta Mol Basis Dis. 2024 Aug 15. pii: S0925-4439(24)00463-0. [Epub ahead of print]1870(8): 167470
    Accumulation of damaged mitochondria in aging astrocytes due to mitophagy dysfunction: Implications for susceptibility to mitochondrial stress.
    Luan Pereira Diniz, Ana Paula Bergamo Araujo, Clara Fernandes Carvalho, Isadora Matias, Lívia de Sá Hayashide, Mariana Marques, Bruna Pessoa, Cherley Borba Vieira Andrade, Gabriele Vargas, Daniela Dias Queiroz, Jorge José de Carvalho, Antonio Galina, Flávia Carvalho Alcantara Gomes.
      Aging disrupts brain function, leading to cognitive decline and neurodegenerative diseases. Senescent astrocytes, a hallmark of aging, contribute to this process through unknown mechanisms. This study investigates how senescence impacts astrocytic mitochondrial dynamics, which are critical for brain health. Our research, conducted using aged mouse brains, represents the first evidence of morphologically damaged mitochondria in astrocytes, along with functional alterations in mitochondrial respiration. In vitro experiments revealed that senescent astrocytes exhibit an increase in mitochondrial fragmentation and impaired mitophagy. Concurrently, there was an upregulation of mitochondrial biogenesis, indicating a compensatory response to mitochondrial damage. Importantly, these senescent astrocytes were more susceptible to mitochondrial stress, a vulnerability reversed by rapamycin treatment. These findings suggest a potential link between senescence, impaired mitochondrial quality control, and increased susceptibility to mitochondrial stress in astrocytes. Overall, our study highlights the importance of addressing mitochondrial dysfunction and senescence-related changes in astrocytes as a promising approach for developing therapies to counter age-related neurodegeneration and improve brain health.
    Keywords:  Aging; Astrocytes; Mitochondria and senescence
    DOI:  https://doi.org/10.1016/j.bbadis.2024.167470
  64. Chem Soc Rev. 2024 Aug 22.
    Proteolysis-targeting drug delivery system (ProDDS): integrating targeted protein degradation concepts into formulation design.
    Yu Chen, Fengyuan Liu, Samira Pal, Quanyin Hu.
      Targeted protein degradation (TPD) has emerged as a revolutionary paradigm in drug discovery and development, offering a promising avenue to tackle challenging therapeutic targets. Unlike traditional drug discovery approaches that focus on inhibiting protein function, TPD aims to eliminate proteins of interest (POIs) using modular chimeric structures. This is achieved through the utilization of proteolysis-targeting chimeras (PROTACs), which redirect POIs to E3 ubiquitin ligases, rendering them for degradation by the cellular ubiquitin-proteasome system (UPS). Additionally, other TPD technologies such as lysosome-targeting chimeras (LYTACs) and autophagy-based protein degraders facilitate the transportation of proteins to  endo-lysosomal or autophagy-lysosomal pathways for degradation, respectively. Despite significant growth in preclinical TPD research, many chimeras fail to progress beyond this stage in the drug development. Various factors contribute to the limited success of TPD agents, including a significant hurdle of inadequate delivery to the target site. Integrating TPD into delivery platforms could surmount the challenges of in vivo applications of TPD strategies by reshaping their pharmacokinetics and pharmacodynamic profiles. These proteolysis-targeting drug delivery systems (ProDDSs) exhibit superior delivery performance, enhanced targetability, and reduced off-tissue side effects. In this review, we will survey the latest progress in TPD-inspired drug delivery systems, highlight the importance of introducing delivery ideas or technologies to the development of protein degraders, outline design principles of protein degrader-inspired delivery systems, discuss the current challenges, and provide an outlook on future opportunities in this field.
    DOI:  https://doi.org/10.1039/d4cs00411f
  65. J Control Release. 2024 Aug 14. pii: S0168-3659(24)00563-7. [Epub ahead of print]
    An "Iron-phagy" nanoparticle inducing irreversible mitochondrial damages for antitumor therapy.
    Zixu Wang, Shanshan Xiang, Yihe Qiu, Fangying Yu, Sufen Li, Shufen Zhang, Guangtao Song, Yichong Xu, Tingting Meng, Hong Yuan, Fuqiang Hu.
      Cellular iron is inseparably related with the proper functionalities of mitochondria for its potential to readily donate and accept electrons. Though promising, the available endeavors of iron chelation antitumor therapies have tended to be adjuvant therapies. Herein, we conceptualized and fabricated an "iron-phagy" nanoparticle (Dp44mT@HTH) capable of inducing the absolute devastation of mitochondria via inhibiting the autophagy-removal of impaired ones for promoting cancer cell death. The Dp44mT@HTH with hyaluronic acid (HA) as hydrophilic shell can specifically target the highly expressed CD44 receptors on the surface of 4 T1 tumor cells. After internalization and lysosomal escape, the nanoparticle disassembles in response to the reactive oxygen species (ROS), subsequently releasing the iron chelator Dp44mT and autophagy-inhibitory drug hydroxychloroquine (HCQ). Dp44mT can then seize cellular Fe2+ to trigger mitochondrial dysfunction via respiratory chain disturbance, while HCQ not only lessens Fe2+ intake, but also impedes fusions of autophagosomes and lysosomes. Consequentially, Dp44mT@HTH induces irreversible mitochondrial impairments, in this respect creating a substantial toxic stack state that induces apoptosis and cell death. Initiating from the perspective of endogenous substances, this strategy illuminates the promise of iron depletion therapy via irreversible mitochondrial damage induction for anticancer treatment.
    Keywords:  Antitumor strategy; Autophagy; Cellular irons; Mitochondria dysfunction; iron chelation
    DOI:  https://doi.org/10.1016/j.jconrel.2024.08.024
  66. Anal Chem. 2024 Aug 18.
    Twisted Intramolecular Charge Transfer-Based Viscosity-Responsive Probe Reveals Lysosomal Degradation Process of Endocytosed Foreign Bodies.
    He Li, Jingchen Zhang, Huaijiang Li, Ensheng Zhang, Weiheng Kong, Rongmei Kong, Yan Zhao, Fengli Qu, Weihong Tan.
      The optimization of nanomedicines requires a thorough understanding of nanocarrier attrition during lysosome-mediated biological processes. Real-time monitoring of endocytosis provides valuable insights into the lysosomal effects on nanocarriers and the release of nanodrugs. We report the development of a coresponsive probe that detects changes in the spatial viscosity of the intracellular domain caused by lysosomal degradation of foreign bodies. The probe, based on a benzofuro[2,3-d]pyrimidine structure, exhibits torsional intramolecular charge transfer (TICT) and responds to ambient viscosity changes with a sensitive fluorescence intensity. The antidiffused fluorescence transition of the probe in the spatially restricted domain serves as a key indicator for real-time monitoring. When encapsulated with diverse foreign bodies and emitted into macrophages by endocytosis, the probe forms nanoparticles. Lysosomes uptake these materials for intracellular digestion, causing alterations in the aggregation or depolymerization state of the nanoparticles, leading to viscosity changes manifested by the probe's fluorescence. By studying the spatial viscosity changes caused by lysosomal degradation of foreign bodies, our monitoring strategy contributes to understanding the digestion or escape capabilities of potential pharmaceutical-carrying nanocarriers, providing guidelines to design more effective nanocarriers that navigate lysosomal degradation to achieve precise drug payloads and release.
    DOI:  https://doi.org/10.1021/acs.analchem.4c02729
  67. Nat Cell Biol. 2024 Aug 22.
    The Rubicon-WIPI axis regulates exosome biogenesis during ageing.
    Kyosuke Yanagawa, Akiko Kuma, Maho Hamasaki, Shunbun Kita, Tadashi Yamamuro, Kohei Nishino, Shuhei Nakamura, Hiroko Omori, Tatsuya Kaminishi, Satoshi Oikawa, Yoshio Kato, Ryuya Edahiro, Ryosuke Kawagoe, Takako Taniguchi, Yoko Tanaka, Takayuki Shima, Keisuke Tabata, Miki Iwatani, Nao Bekku, Rikinari Hanayama, Yukinori Okada, Takayuki Akimoto, Hidetaka Kosako, Akiko Takahashi, Iichiro Shimomura, Yasushi Sakata, Tamotsu Yoshimori.
      Cells release intraluminal vesicles in multivesicular bodies as exosomes to communicate with other cells. Although recent studies suggest an intimate link between exosome biogenesis and autophagy, the detailed mechanism is not fully understood. Here we employed comprehensive RNA interference screening for autophagy-related factors and discovered that Rubicon, a negative regulator of autophagy, is essential for exosome release. Rubicon recruits WIPI2d to endosomes to promote exosome biogenesis. Interactome analysis of WIPI2d identified the ESCRT components that are required for intraluminal vesicle formation. Notably, we found that Rubicon is required for an age-dependent increase of exosome release in mice. In addition, small RNA sequencing of serum exosomes revealed that Rubicon determines the fate of exosomal microRNAs associated with cellular senescence and longevity pathways. Taken together, our current results suggest that the Rubicon-WIPI axis functions as a key regulator of exosome biogenesis and is responsible for age-dependent changes in exosome quantity and quality.
    DOI:  https://doi.org/10.1038/s41556-024-01481-0
  68. STAR Protoc. 2024 Aug 22. pii: S2666-1667(24)00346-0. [Epub ahead of print]5(3): 103181
    Protocol for quantifying LC3B FRET biosensor activity in living cells using a broad-to-sensitive data analysis pipeline.
    Elif Begüm Gökerküçük, Marc Tramier, Giulia Bertolin.
      Here, we present a protocol to comprehensively quantify autophagy initiation using the readout of the microtubule associated protein 1 light chain 3 beta (LC3B) Förster's resonance energy transfer (FRET) biosensor. We describe steps for cell seeding, transfection, FRET/FLIM (fluorescence lifetime imaging microscopy) imaging, and image analysis. This protocol can be useful in any physiology- or disease-related paradigm where the LC3B biosensor can be expressed to determine whether autophagy has been initiated or is stalled. The analysis pipeline presented here can be applied to any other genetically encoded FRET sensor imaged using FRET/FLIM. For complete details on the use and execution of this protocol, please refer to Gökerküçük et al.1.
    Keywords:  Cell-based Assays; Microscopy; Molecular/Chemical Probes; Single Cell
    DOI:  https://doi.org/10.1016/j.xpro.2024.103181
  69. Bioessays. 2024 Aug 19. e2400090
    FAM210A: An emerging regulator of mitochondrial homeostasis.
    Yubo Wang, Feng Yue.
      Mitochondrial homeostasis serves as a cornerstone of cellular function, orchestrating a delicate balance between energy production, redox status, and cellular signaling transduction. This equilibrium involves a myriad of interconnected processes, including mitochondrial dynamics, quality control mechanisms, and biogenesis and degradation. Perturbations in mitochondrial homeostasis have been implicated in a wide range of diseases, including neurodegenerative diseases, metabolic syndromes, and aging-related disorders. In the past decades, the discovery of numerous mitochondrial proteins and signaling has led to a more complete understanding of the intricate mechanisms underlying mitochondrial homeostasis. Recent studies have revealed that Family with sequence similarity 210 member A (FAM210A) is a novel nuclear-encoded mitochondrial protein involved in multiple aspects of mitochondrial homeostasis, including mitochondrial quality control, dynamics, cristae remodeling, metabolism, and proteostasis. Here, we review the function and physiological role of FAM210A in cellular and organismal health. This review discusses how FAM210A acts as a regulator on mitochondrial inner membrane to coordinate mitochondrial dynamics and metabolism.
    Keywords:  FAM210A; cristae remodeling; energy metabolism; mitochondrial dynamics; proteostasis; quality control
    DOI:  https://doi.org/10.1002/bies.202400090
  70. Cardiovasc Res. 2024 Aug 22. pii: cvae177. [Epub ahead of print]
    Anti-ageing interventions for the treatment of cardiovascular disease.
    Mahmoud Abdellatif, Sophie T Schmid, Alexander Fuerlinger, Guido Kroemer.
      As the global demographic landscape continues to shift towards an aged population, so does the medical and socioeconomic burden of cardiovascular diseases. Indeed, ageing is one of, if not the, key risk factor for the development of cardiovascular diseases. However, there are currently no approved cardiovascular therapeutics that primarily target the molecular and cellular mechanisms underlying the ageing process itself. In this review, we present the potential of emerging anti-ageing strategies, including epigenetic rejuvenation, metabolic reprogramming, autophagy activation, as well as senolytic and anti-inflammatory therapies, in delaying or reversing the development of age-related cardiovascular disorders, while considering potential sex differences. In doing so, we implicate cellular ageing processes in the pathogenesis of several prevalent cardiovascular diseases, such as atherosclerosis, hypertension, various types of cardiomyopathies (including its hypertrophic, ischemic, dilated, diabetic, and arrhythmogenic forms) and heart failure, particularly that with preserved ejection fraction. Finally, we outline future challenges and steps needed for the implementation of these novel anti-ageing strategies in the clinical setting, with the aim of challenging the long-held notion of ageing as a 'nonmodifiable' risk factor for cardiovascular diseases.
    DOI:  https://doi.org/10.1093/cvr/cvae177
  71. Heliyon. 2024 Aug 15. 10(15): e34963
    The prion-like effect and prion-like protein targeting strategy in amyotrophic lateral sclerosis.
    Yang Wenzhi, Liu Xiangyi, Fan Dongsheng.
      Pathological proteins in amyotrophic lateral sclerosis (ALS), such as superoxide dismutase 1, TAR DNA-binding protein 43, and fused in sarcoma, exhibit a prion-like pattern. All these proteins have a low-complexity domain and seeding activity in cells. In this review, we summarize the studies on the prion-like effect of these proteins and list six prion-like protein targeting strategies that we believe have potential for ALS therapy, including antisense oligonucleotides, antibody-based technology, peptide, protein chaperone, autophagy enhancement, and heteromultivalent compounds. Considering the pathological complexity and heterogeneity of ALS, we believe that the final solution to ALS therapy is most likely to be an individualized cocktail therapy, including clearance of toxicity, blockage of pathological progress, and protection of neurons.
    Keywords:  ALS; Prion-like; Protein
    DOI:  https://doi.org/10.1016/j.heliyon.2024.e34963
  72. Biomed Pharmacother. 2024 Aug 20. pii: S0753-3322(24)01197-1. [Epub ahead of print]179 117313
    The autophagy-targeting compound V46 enhances antimicrobial responses to Mycobacteroides abscessus by activating transcription factor EB.
    Asmita Sapkota, Eun-Jin Park, Young Jae Kim, Jong Beom Heo, Thanh Quang Nguyen, Bo Eun Heo, Jin Kyung Kim, Sang-Hee Lee, Soo In Kim, Yoon-Jung Choi, Taylor Roh, Sang Min Jeon, Marnpyung Jang, Hae Joon Heo, Jake Whang, Seungwha Paik, Jae-Min Yuk, Jin-Man Kim, Gyu Yong Song, Jichan Jang, Eun-Kyeong Jo.
      Mycobacteroides abscessus (Mabc) is a rapidly growing nontuberculous mycobacterium that poses a considerable challenge as a multidrug-resistant pathogen causing chronic human infection. Effective therapeutics that enhance protective immune responses to Mabc are urgently needed. This study introduces trans-3,5,4'-trimethoxystilbene (V46), a novel resveratrol analogue with autophagy-activating properties and antimicrobial activity against Mabc infection, including multidrug-resistant strains. Among the resveratrol analogues tested, V46 significantly inhibited the growth of both rough and smooth Mabc strains, including multidrug-resistant strains, in macrophages and in the lungs of mice infected with Mabc. Additionally, V46 substantially reduced Mabc-induced levels of pro-inflammatory cytokines and chemokines in both macrophages and during in vivo infection. Mechanistic analysis showed that V46 suppressed the activation of the protein kinase B/Akt-mammalian target of rapamycin signaling pathway and enhanced adenosine monophosphate-activated protein kinase signaling in Mabc-infected cells. Notably, V46 activated autophagy and the nuclear translocation of transcription factor EB, which is crucial for antimicrobial host defenses against Mabc. Furthermore, V46 upregulated genes associated with autophagy and lysosomal biogenesis in Mabc-infected bone marrow-derived macrophages. The combination of V46 and rifabutin exerted a synergistic antimicrobial effect. These findings identify V46 as a candidate host-directed therapeutic for Mabc infection that activates autophagy and lysosomal function via transcription factor EB.
    Keywords:  Autophagy; Host defense; Inflammation; Mycobacteroides abscessus; Transcription factor EB; V46
    DOI:  https://doi.org/10.1016/j.biopha.2024.117313
  73. Nature. 2024 Aug 21.
    Short-term post-fast refeeding enhances intestinal stemness via polyamines.
    Shinya Imada, Saleh Khawaled, Heaji Shin, Sven W Meckelmann, Charles A Whittaker, Renan Oliveira Corrêa, Chiara Alquati, Yixin Lu, Guodong Tie, Dikshant Pradhan, Gizem Calibasi-Kocal, Luiza Martins Nascentes Melo, Gabriele Allies, Jonas Rösler, Pia Wittenhofer, Jonathan Krystkiewicz, Oliver J Schmitz, Jatin Roper, Marco Aurelio Ramirez Vinolo, Luigi Ricciardiello, Evan C Lien, Matthew G Vander Heiden, Ramesh A Shivdasani, Chia-Wei Cheng, Alpaslan Tasdogan, Ömer H Yilmaz.
      For over a century, fasting regimens have improved health, lifespan and tissue regeneration in diverse organisms, including humans1-6. However, how fasting and post-fast refeeding affect adult stem cells and tumour formation has yet to be explored in depth. Here we demonstrate that post-fast refeeding increases intestinal stem cell (ISC) proliferation and tumour formation; post-fast refeeding augments the regenerative capacity of Lgr5+ ISCs, and loss of the tumour suppressor gene Apc in post-fast-refed ISCs leads to a higher tumour incidence in the small intestine and colon than in the fasted or ad libitum-fed states, demonstrating that post-fast refeeding is a distinct state. Mechanistically, we discovered that robust mTORC1 induction in post-fast-refed ISCs increases protein synthesis via polyamine metabolism to drive these changes, as inhibition of mTORC1, polyamine metabolite production or protein synthesis abrogates the regenerative or tumorigenic effects of post-fast refeeding. Given our findings, fast-refeeding cycles must be carefully considered and tested when planning diet-based strategies for regeneration without increasing cancer risk, as post-fast refeeding leads to a burst in stem-cell-driven regeneration and tumorigenicity.
    DOI:  https://doi.org/10.1038/s41586-024-07840-z
  74. Autophagy. 2024 Aug 22.
    TRIM21-mediated ubiquitination of SQSTM1/p62 abolishes its Ser403 phosphorylation and enhances palmitic acid cytotoxicity.
    Peng Yang, Shenglan Gao, Jianliang Shen, Tong Liu, Kevin Lu, Xinlu Han, Jun Wang, Hong-Min Ni, Wen-Xing Ding, Hong Li, Ji-An Pan, Kesong Peng, Wei-Xing Zong.
      Long-chain free fatty acids (FFAs) accumulation and oxidative toxicity is a major cause for several pathological conditions. The mechanisms underlying FFA cytotoxicity remain elusive. Here we show that palmitic acid (PA), the most abundant FFA in the circulation, induces S403 phosphorylation of SQSTM1/p62 (sequestosome 1) and its aggregation, which sequesters KEAP1 and activates the non-canonical SQSTM1-KEAP1-NFE2L2 antioxidant pathway. The PA-induced SQSTM1 S403 phosphorylation and aggregation are dependent on SQSTM1 K7-D69 hydrogen bond formation and dimerization in the Phox and Bem1 (PB1) domain, which facilitates the recruitment of TBK1 that phosphorylates SQSTM1 S403. The ubiquitin E3 ligase TRIM21 ubiquitinates SQSTM1 at the K7 residue and abolishes the PB1 dimerization, S403 phosphorylation, and SQSTM1 aggregation. TRIM21 is oxidized at C92, C111, and C114 to form disulfide bonds that lead to its oligomerization and decreased E3 activity. Mutagenizing the three C residues to S (3CS) abolishes TRIM21 oligomerization and increases its E3 activity. TRIM21 ablation leads to decreased SQSTM1 K7 ubiquitination, hence elevated SQSTM1 S403 phosphorylation and aggregation, which confers protection against PA-induced oxidative stress and cytotoxicity. Therefore, TRIM21 is a negative regulator of SQSTM1 phosphorylation, aggregation, and the antioxidant sequestration function. TRIM21 is oxidized to reduce its E3 activity that helps enhance the SQSTM1-KEAP1-NFE2L2 antioxidant pathway. Inhibition of TRIM21 May be a viable strategy to protect tissues from lipotoxicity resulting from long-chain FFAs.
    Keywords:  Free fatty acids; KEAP1; NFE2L2; ROS; lipotoxicity; liver damage
    DOI:  https://doi.org/10.1080/15548627.2024.2394308
  75. Proc Natl Acad Sci U S A. 2024 Aug 27. 121(35): e2400385121
    The microbiota-dependent tryptophan metabolite alleviates high-fat diet-induced insulin resistance through the hepatic AhR/TSC2/mTORC1 axis.
    Wei Du, Shanshan Jiang, Shengxiang Yin, Rongjiang Wang, Chunling Zhang, Bin-Cheng Yin, Jialin Li, Li Li, Nan Qi, Ying Zhou, Bang-Ce Ye.
      Type 2 diabetes (T2D) is potentially linked to disordered tryptophan metabolism that attributes to the intricate interplay among diet, gut microbiota, and host physiology. However, underlying mechanisms are substantially unknown. Comparing the gut microbiome and metabolome differences in mice fed a normal diet (ND) and high-fat diet (HFD), we uncover that the gut microbiota-dependent tryptophan metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) is present at lower concentrations in mice with versus without insulin resistance. We further demonstrate that the microbial transformation of tryptophan into 5-HIAA is mediated by Burkholderia spp. Additionally, we show that the administration of 5-HIAA improves glucose intolerance and obesity in HFD-fed mice, while preserving hepatic insulin sensitivity. Mechanistically, 5-HIAA promotes hepatic insulin signaling by directly activating AhR, which stimulates TSC2 transcription and thus inhibits mTORC1 signaling. Moreover, T2D patients exhibit decreased fecal levels of 5-HIAA. Our findings identify a noncanonical pathway of microbially producing 5-HIAA from tryptophan and indicate that 5-HIAA might alleviate the pathogenesis of T2D.
    Keywords:  gut microbiota; insulin signaling; tryptophan metabolism; type 2 diabetes
    DOI:  https://doi.org/10.1073/pnas.2400385121
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