bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2023–08–13
58 papers selected by
Viktor Korolchuk, Newcastle University
  1. Chloroplast microautophagy: A green role for NBR1.
  2. Lactate is a bridge linking glycolysis and autophagy through lactylation.
  3. Inhibition of autophagy and induction of glioblastoma cell death by NEO214, a perillyl alcohol-rolipram conjugate.
  4. Post-transcriptional dynamics and RNA homeostasis in autophagy and cancer.
  5. Protein disorder in the regulatory control of mitophagy.
  6. Activated STING1 rides the Rafeesome.
  7. Malonyl-CoA is a conserved endogenous ATP-competitive mTORC1 inhibitor.
  8. Autophagy modulates the stability of Wee1 and cell cycle G2/M transition.
  9. Dichotomous role of autophagy in cancer.
  10. A conserved membrane curvature-generating protein is crucial for autophagosome formation in fission yeast.
  11. Lysosomal acidification dysfunction in microglia: an emerging pathogenic mechanism of neuroinflammation and neurodegeneration.
  12. Live-Cell High-Throughput Screen for Monitoring Autophagy Flux.
  13. JNK-interacting protein 4 is a central molecule for lysosomal retrograde trafficking.
  14. Transformed cells maintain survival by downregulating autophagy at a high cell confluency.
  15. The role of the HORMA domain proteins ATG13 and ATG101 in initiating autophagosome biogenesis.
  16. Dysregulation of Histone Deacetylases Inhibits Trophoblast Growth during Early Placental Development Partially through TFEB-Dependent Autophagy-Lysosomal Pathway.
  17. Autophagy as a caretaker of nuclear integrity.
  18. The small peptide VISP1 acts as a selective autophagy receptor regulating plant-virus interactions.
  19. The roles of METTL3 on autophagy and proliferation of vascular smooth muscle cells are mediated by mTOR rather than by CDK1.
  20. Oculopharyngeal muscular dystrophy mutations link the RNA-binding protein HNRNPQ to autophagosome biogenesis.
  21. Cypermethrin induces endoplasmic reticulum stress and autophagy, leads to testicular dysfunction.
  22. TMEM175 downregulation participates in impairment of the autophagy related lysosomal dynamics following neonatal hypoxic-ischemic brain injury.
  23. Interaction mechanisms between autophagy and ferroptosis: Potential role in colorectal cancer.
  24. Ezh2 promotes mammary tumor initiation through epigenetic regulation of the Wnt and mTORC1 signaling pathways.
  25. Targeting SARM1 improves autophagic stress-induced axonal neuropathy.
  26. VPS41-mediated incomplete autophagy aggravates cadmium-induced apoptosis in mouse hepatocytes.
  27. Seizure reduction in TSC2-mutant mouse model by an mTOR catalytic inhibitor.
  28. Interactome of Arabidopsis ATG5 Suggests Functions beyond Autophagy.
  29. Potential relationship between autophagy and ferroptosis in myocardial ischemia/reperfusion injury.
  30. Glial cells LAP axon fragments.
  31. Impaired Lysosome Reformation in Chloroquine-Treated Retinal Pigment Epithelial Cells.
  32. Unveiling the hypoxia-induced mitophagy process through two-channel real-time imaging of NTR and viscosity under the same excitation.
  33. TET2 is required to suppress mTORC1 signaling through urea cycle with therapeutic potential.
  34. SQSTM1 is a therapeutic target for infection and sterile inflammation.
  35. Protection of c-Fos from autophagic degradation by PRMT1-mediated methylation fosters gastric tumorigenesis.
  36. Pathological study of proximal tubule mitochondria in diclofenac-induced acute kidney injury model mice.
  37. Parkinson's disease neurons exhibit alterations in mitochondrial quality control proteins.
  38. Natriuretic Peptide Signaling in Uterine Biology and Preeclampsia.
  39. Implication of mTOR Signaling in NSCLC: Mechanisms and Therapeutic Perspectives.
  40. Autophagy promotes jasmonate-mediated defense against nematodes.
  41. Autophagy collaborates with apoptosis pathways to control oligodendrocyte number.
  42. From Acid Alpha-Glucosidase Deficiency to Autophagy: Understanding the Bases of POMPE Disease.
  43. Metformin and Trehalose-Modulated Autophagy Exerts a Neurotherapeutic Effect on Parkinson's Disease.
  44. TMEM106B aggregation in neurodegenerative diseases: linking genetics to function.
  45. The ubiquitin ligase TRIM32 promotes the autophagic response to Mycobacterium tuberculosis infection in macrophages.
  46. Malonyl-CoA links lipid metabolism to nutrient signalling by directly inhibiting mTORC1.
  47. High BECN1 Expression Negatively Correlates with BCL2 Expression and Predicts Better Prognosis in Diffuse Large B-Cell Lymphoma: Role of Autophagy.
  48. Rab44 negatively regulates myoblast differentiation by controlling fusogenic protein transport and mTORC1 signaling.
  49. Paradigm shift in the treatment of tuberous sclerosis: effectiveness of everolimus.
  50. The Role of Mitophagy in Glaucomatous Neurodegeneration.
  51. CircHIPK3 contributes to cisplatin resistance in gastric cancer by blocking autophagy-dependent ferroptosis.
  52. Autophagy Inhibition via Hydroxychloroquine or 3-Methyladenine Enhances Chemotherapy-Induced Apoptosis in Neuro-Blastoma and Glioblastoma.
  53. Autophagy-dependent ferroptosis is involved in the development of endometriosis.
  54. FBXL4 mutations cause excessive mitophagy via BNIP3/BNIP3L accumulation leading to mitochondrial DNA depletion syndrome.
  55. Rab44 deficiency accelerates recovery from muscle damage by regulating mTORC1 signaling and transport of fusogenic regulators.
  56. TUNEL-positive structures in activated microglia and SQSTM1/p62-positive structures in activated astrocytes in the neurodegenerative brain of a CLN10 mouse model.
  57. The Multikinase Inhibitor AD80 Induces Mitotic Catastrophe and Autophagy in Pancreatic Cancer Cells.
  58. Rege-1 promotes C. elegans survival by modulating IIS and TOR pathways.
  1. Autophagy. 2023 Aug 10.
    Chloroplast microautophagy: A green role for NBR1.
    Han Nim Lee, Sarika K Marathe, Marisa S Otegui.
      
    Keywords:  Autophagy receptor; NBR1; chlorophagy; chloroplast turnover; microautophagy; non-canonical autophagy; selective autophagy
    DOI:  https://doi.org/10.1080/15548627.2023.2246857
  2. Autophagy. 2023 Aug 11.
    Lactate is a bridge linking glycolysis and autophagy through lactylation.
    Weixia Sun, Mengshu Jia, Yingyan Feng, Xiawei Cheng.
      Lactate is a glycolysis product that is produced from pyruvate by LDH (lactate dehydrogenase) and plays an important role in physiological and pathological processes. However, whether lactate regulates autophagy is still unknown. We recently reported that LDHA is phosphorylated at serine 196 by ULK1 (unc-51 like kinase 1) under nutrient-deprivation conditions, promoting lactate production. Then, lactate mediates PIK3C3/VPS34 lactylation at lysine 356 and lysine 781 via acyltransferase KAT5/TIP60. PIK3C3/VPS34 lactylation enhances the association of PIK3C3/VPS34 with BECN1 (beclin 1, autophagy related), ATG14 and UVRAG, increases PIK3C3/VPS34 lipid kinase activity, promotes macroautophagy/autophagy and facilitates the endolysosomal degradation pathway. PIK3C3/VPS34 hyperlactylation induces autophagy and plays an essential role in skeletal muscle homeostasis and cancer progression. Overall, this study describes an autophagy regulation mechanism and the integration of two highly conserved life processes: glycolysis and autophagy.
    DOI:  https://doi.org/10.1080/15548627.2023.2246356
  3. Autophagy. 2023 Aug 06. 1-20
    Inhibition of autophagy and induction of glioblastoma cell death by NEO214, a perillyl alcohol-rolipram conjugate.
    Mengting Ou, Hee-Yeon Cho, Jie Fu, Thu Zan Thein, Weijun Wang, Stephen D Swenson, Radu O Minea, Apostolos Stathopoulos, Axel H Schönthal, Florence M Hofman, Liling Tang, Thomas C Chen.
      Glioblastoma (GBM) is the most aggressive primary brain tumor, exhibiting a high rate of recurrence and poor prognosis. Surgery and chemoradiation with temozolomide (TMZ) represent the standard of care, but, in most cases, the tumor develops resistance to further treatment and the patients succumb to disease. Therefore, there is a great need for the development of well-tolerated, effective drugs that specifically target chemoresistant gliomas. NEO214 was generated by covalently conjugating rolipram, a PDE4 (phosphodiesterase 4) inhibitor, to perillyl alcohol, a naturally occurring monoterpene related to limonene. Our previous studies in preclinical models showed that NEO214 harbors anticancer activity, is able to cross the blood-brain barrier (BBB), and is remarkably well tolerated. In the present study, we investigated its mechanism of action and discovered inhibition of macroautophagy/autophagy as a key component of its anticancer effect in glioblastoma cells. We show that NEO214 prevents autophagy-lysosome fusion, thereby blocking autophagic flux and triggering glioma cell death. This process involves activation of MTOR (mechanistic target of rapamycin kinase) activity, which leads to cytoplasmic accumulation of TFEB (transcription factor EB), a critical regulator of genes involved in the autophagy-lysosomal pathway, and consequently reduced expression of autophagy-lysosome genes. When combined with chloroquine and TMZ, the anticancer impact of NEO214 is further potentiated and unfolds against TMZ-resistant cells as well. Taken together, our findings characterize NEO214 as a novel autophagy inhibitor that could become useful for overcoming chemoresistance in glioblastoma.Abbreviations: ATG: autophagy related; BAFA1: bafilomycin A1; BBB: blood brain barrier; CQ: chloroquine; GBM: glioblastoma; LAMP1: lysosomal associated membrane protein 1; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MGMT: O-6-methylguanine-DNA methyltransferase; MTOR: mechanistic target of rapamycin kinase; MTORC: MTOR complex; POH: perillyl alcohol; SQSTM1/p62: sequestosome 1; TFEB: transcription factor EB; TMZ: temozolomide.
    Keywords:  MTOR complex; NEO214; autophagic flux; chloroquine; glioblastoma; transcription factor EB
    DOI:  https://doi.org/10.1080/15548627.2023.2242696
  4. Cell Death Differ. 2023 Aug 09.
    Post-transcriptional dynamics and RNA homeostasis in autophagy and cancer.
    Srinivasa Prasad Kolapalli, Thorbjørn M Nielsen, Lisa B Frankel.
      Autophagy is an essential recycling and quality control pathway which preserves cellular and organismal homeostasis. As a catabolic process, autophagy degrades damaged and aged intracellular components in response to conditions of stress, including nutrient deprivation, oxidative and genotoxic stress. Autophagy is a highly adaptive and dynamic process which requires an intricately coordinated molecular control. Here we provide an overview of how autophagy is regulated post-transcriptionally, through RNA processing events, epitranscriptomic modifications and non-coding RNAs. We further discuss newly revealed RNA-binding properties of core autophagy machinery proteins and review recent indications of autophagy's ability to impact cellular RNA homeostasis. From a physiological perspective, we examine the biological implications of these emerging regulatory layers of autophagy, particularly in the context of nutrient deprivation and tumorigenesis.
    DOI:  https://doi.org/10.1038/s41418-023-01201-5
  5. Autophagy Rep. 2023 ;pii: 2242054. [Epub ahead of print]2(1):
    Protein disorder in the regulatory control of mitophagy.
    Sheridan Mikhail, Scott A Soleimanpour.
      Mitophagy is a central component of the mitochondrial quality control machinery, which is necessary for cellular viability and bioenergetics. The E3 ubiquitin ligase CLEC16A (C-type lectin domain containing 16A) forms a tripartite mitophagy regulatory complex together with the E3 ligase RNF41 (ring finger protein 41) and the ubiquitin-specific peptidase USP8 (ubiquitin specific peptidase 8), yet CLEC16A structural/functional domains relevant for mitophagy are unknown. We identify that CLEC16A contains an internal intrinsically disordered region (IDR), which is important for CLEC16A function and stability. IDRs are flexible domains lacking fixed secondary structure and regulate an emerging number of diverse processes, yet they have been largely unstudied in mitophagy. We observe that the internal CLEC16A IDR is essential for CLEC16A degradation and is bound by RNF41 to promote CLEC16A turnover. This IDR also promotes assembly of the CLEC16A-RNF41-USP8 mitophagy regulatory complex. Thus, our study revealed the importance of IDRs in mitophagy via the regulation of CLEC16A abundance by RNF41, opening new structural insights into mitochondrial quality control.
    Keywords:  autophagy; clec16a; intrinsically disordered protein; mitochondria; ubiquitin
    DOI:  https://doi.org/10.1080/27694127.2023.2242054
  6. Autophagy. 2023 Aug 06. 1-4
    Activated STING1 rides the Rafeesome.
    Yaping Han, Jianfei Zheng, Liang Ge.
      Over the past decade, accumulated studies have reported the presence of non-canonical macroautophagy/autophagy characterized by the shared usage of the autophagy machinery and distinct components that function in multiple scenarios but do not involve lysosomal degradation. One type of non-canonical autophagy is secretory autophagy, which facilitates the secretion of various cargoes. In a recent work from Gao et al. the ER-membrane protein STING1 has been identified as a novel substrate of secretory autophagy. The secretion of activated STING1 is mediated by its packing into the rafeesome, a newly identified organelle formed upon the fusion of RAB22A-mediated non-canonical autophagosome with an early endosome. Moreover, extracellular vesicles containing activated STING1 induce antitumor immunity in recipient cells, a process potentially promoted by RAB22A.
    Keywords:  Autophagosome; ERGIC; RAB22; Rafeesome; STING; Unconventional secretion
    DOI:  https://doi.org/10.1080/15548627.2023.2240154
  7. Nat Cell Biol. 2023 Aug 10.
    Malonyl-CoA is a conserved endogenous ATP-competitive mTORC1 inhibitor.
    Raffaele Nicastro, Laura Brohée, Josephine Alba, Julian Nüchel, Gianluca Figlia, Stefanie Kipschull, Peter Gollwitzer, Jesus Romero-Pozuelo, Stephanie A Fernandes, Andreas Lamprakis, Stefano Vanni, Aurelio A Teleman, Claudio De Virgilio, Constantinos Demetriades.
      Cell growth is regulated by the mammalian/mechanistic target of rapamycin complex 1 (mTORC1), which functions both as a nutrient sensor and a master controller of virtually all biosynthetic pathways. This ensures that cells are metabolically active only when conditions are optimal for growth. Notably, although mTORC1 is known to regulate fatty acid biosynthesis, how and whether the cellular lipid biosynthetic capacity signals back to fine-tune mTORC1 activity remains poorly understood. Here we show that mTORC1 senses the capacity of a cell to synthesise fatty acids by detecting the levels of malonyl-CoA, an intermediate of this biosynthetic pathway. We find that, in both yeast and mammalian cells, this regulation is direct, with malonyl-CoA binding to the mTOR catalytic pocket and acting as a specific ATP-competitive inhibitor. When fatty acid synthase (FASN) is downregulated/inhibited, elevated malonyl-CoA levels are channelled to proximal mTOR molecules that form direct protein-protein interactions with acetyl-CoA carboxylase 1 (ACC1) and FASN. Our findings represent a conserved and unique homeostatic mechanism whereby impaired fatty acid biogenesis leads to reduced mTORC1 activity to coordinately link this metabolic pathway to the overall cellular biosynthetic output. Moreover, they reveal the existence of a physiological metabolite that directly inhibits the activity of a signalling kinase in mammalian cells by competing with ATP for binding.
    DOI:  https://doi.org/10.1038/s41556-023-01198-6
  8. Biochem Biophys Res Commun. 2023 Aug 04. pii: S0006-291X(23)00942-7. [Epub ahead of print]677 63-69
    Autophagy modulates the stability of Wee1 and cell cycle G2/M transition.
    Biwei Han, Yajing Chen, Chen Song, Yali Chen, Yong Chen, Daniel Ferguson, Yunzhi Yang, Anyuan He.
      The mammalian cell cycle is divided into four sequential phases, namely G1 (Gap 1), S (synthesis), G2 (Gap 2), and M (mitosis). Wee1, whose turnover is tightly and finely regulated, is a well-known kinase serving as a gatekeeper for the G2/M transition. However, the mechanism underlying the turnover of Wee1 is not fully understood. Autophagy, a highly conserved cellular process, maintains cellular homeostasis by eliminating intracellular aggregations, damaged organelles, and individual proteins. In the present study, we found autophagy deficiency in mouse liver caused G2/M arrest in two mouse models, namely Fip200 and Atg7 liver-specific knockout mice. To uncover the link between autophagy deficiency and G2/M transition, we combined transcriptomic and proteomic analysis for liver samples from control and Atg7 liver-specific knockout mice. The data suggest that the inhibition of autophagy increases the protein level of Wee1 without any alteration of its mRNA abundance. Serum starvation, an autophagy stimulus, downregulates the protein level of Wee1 in vitro. In addition, the half-life of Wee1 is extended by the addition of chloroquine, an autophagy inhibitor. LC3, a central autophagic protein functioning in autophagy substrate selection and autophagosome biogenesis, interacts with Wee1 as assessed by co-immunoprecipitation assay. Furthermore, overexpression of Wee1 leads to G2/M arrest both in vitro and in vivo. Collectively, our data indicate that autophagy could degrade Wee1-a gatekeeper of the G2/M transition, whereas the inhibition of autophagy leads to the accumulation of Wee1 and causes G2/M arrest in mouse liver.
    DOI:  https://doi.org/10.1016/j.bbrc.2023.08.010
  9. Asian Biomed (Res Rev News). 2022 Jun;16(3): 111-120
    Dichotomous role of autophagy in cancer.
    Amin Arif, Muhammad Babar Khawar, Rabia Mehmood, Muddasir Hassan Abbasi, Nadeem Sheikh.
      Autophagy is an evolutionary conserved catabolic process that plays physiological and pathological roles in a cell. Its effect on cellular metabolism, the proteome, and the number and quality of organelles, diversely holds the potential to alter cellular functions. It acts paradoxically in cancer as a tumor inhibitor as well as a tumor promoter. In the early stage of tumorigenesis, it prevents tumor initiation by the so-called "quality control mechanism" and suppresses cancer progression. For late-staged tumors that are exposed to stress, it acts as a vibrant process of degradation and recycling that promotes cancer by facilitating metastasis. Despite this dichotomy, the crucial role of autophagy is evident in cancer, and associated with mammalian targets of rapamycin (mTOR), p53, and Ras-derived major cancer networks. Irrespective of the controversy regarding autophagic manipulation, promotion and suppression of autophagy act as potential therapeutic targets in cancer treatment and may provide various anticancer therapies.
    Keywords:  autophagy; carcinogenesis; neoplasms; pathology; recycling therapeutics
    DOI:  https://doi.org/10.2478/abm-2022-0014
  10. Nat Commun. 2023 08 08. 14(1): 4765
    A conserved membrane curvature-generating protein is crucial for autophagosome formation in fission yeast.
    Ning Wang, Yoko Shibata, Joao A Paulo, Steven P Gygi, Tom A Rapoport.
      Organelles are shaped by curvature-generating proteins, which include the reticulons and REEPs that are involved in forming the endoplasmic reticulum (ER). A conserved REEP subfamily differs from the ER-shaping REEPs in abundance and membrane topology and has unidentified functions. Here, we show that Rop1, the single member of this family in the fission yeast Schizosacharomyces pombe, is crucial for the macroautophagy of organelles and cytosolic proteins. Rop1 is needed for the formation of phagophores, cup-like structures consisting of two closely apposed membrane sheets that encapsulate cargo. It is recruited at early stages to phagophores and is required for their maturation into autophagosomes. Rop1 function relies on its ability to generate high membrane curvature and on its colocalization with the autophagy component Atg2 that is thought to reside at the phagophore rim. We propose that Rop1 facilitates the formation and growth of the double-membrane structure of the autophagosome.
    DOI:  https://doi.org/10.1038/s41467-023-40530-4
  11. J Neuroinflammation. 2023 Aug 05. 20(1): 185
    Lysosomal acidification dysfunction in microglia: an emerging pathogenic mechanism of neuroinflammation and neurodegeneration.
    Joseph D Quick, Cristian Silva, Jia Hui Wong, Kah Leong Lim, Richard Reynolds, Anna M Barron, Jialiu Zeng, Chih Hung Lo.
      Microglia are the resident innate immune cells in the brain with a major role in orchestrating immune responses. They also provide a frontline of host defense in the central nervous system (CNS) through their active phagocytic capability. Being a professional phagocyte, microglia participate in phagocytic and autophagic clearance of cellular waste and debris as well as toxic protein aggregates, which relies on optimal lysosomal acidification and function. Defective microglial lysosomal acidification leads to impaired phagocytic and autophagic functions which result in the perpetuation of neuroinflammation and progression of neurodegeneration. Reacidification of impaired lysosomes in microglia has been shown to reverse neurodegenerative pathology in Alzheimer's disease. In this review, we summarize key factors and mechanisms contributing to lysosomal acidification impairment and the associated phagocytic and autophagic dysfunction in microglia, and how these defects contribute to neuroinflammation and neurodegeneration. We further discuss techniques to monitor lysosomal pH and therapeutic agents that can reacidify impaired lysosomes in microglia under disease conditions. Finally, we propose future directions to investigate the role of microglial lysosomal acidification in lysosome-mitochondria crosstalk and in neuron-glia interaction for more comprehensive understanding of its broader CNS physiological and pathological implications.
    Keywords:  Acidic nanoparticles; Autophagy; Cytokines; Lysosomal acidification; Neurodegenerative diseases; Neuroinflammation; Phagocytosis; Toxic protein aggregates
    DOI:  https://doi.org/10.1186/s12974-023-02866-y
  12. Methods Mol Biol. 2023 ;2706 215-224
    Live-Cell High-Throughput Screen for Monitoring Autophagy Flux.
    Sara Cano-Franco, Hung Ho-Xuan, Lorene Brunello, Alexandra Stolz.
      Autophagy is a cellular process implicated in the renewal of cellular components and the maintenance of cellular hemostasis and therefore associated with various types of diseases. In addition, autophagy belongs to the stress response pathways and is frequently activated by chemical compounds harboring characteristics of cell toxicity. High-throughput screens analyzing autophagy flux are therefore applied in both, the field of compound identification for targeting autophagy and compound characterization for analyzing compound toxicity. In this chapter, we describe a live-cell, fluorescent-based, high-throughput screening method in 384-well format for the fast and accurate measurement of autophagy flux over time suitable for academic research, pharmacological applications, and drug discovery.
    Keywords:  Autophagy; Fluorescence; GFP-LC3-RFP-LC3ΔG; Incucyte
    DOI:  https://doi.org/10.1007/978-1-0716-3397-7_16
  13. Bioessays. 2023 Aug 09. e2300052
    JNK-interacting protein 4 is a central molecule for lysosomal retrograde trafficking.
    Yukiko Sasazawa, Nobutaka Hattori, Shinji Saiki.
      Lysosomal positioning is an important factor in regulating cellular responses, including autophagy. Because proteins encoded by disease-responsible genes are involved in lysosomal trafficking, proper intracellular lysosomal trafficking is thought to be essential for cellular homeostasis. In the past few years, the mechanisms of lysosomal trafficking have been elucidated with a focus on adapter proteins linking motor proteins to lysosomes. Here, we outline recent findings on the mechanisms of lysosomal trafficking by focusing on adapter protein c-Jun NH2 -terminal kinase-interacting protein (JIP) 4, which plays a central role in this process, and other JIP4 functions and JIP family proteins. Additionally, we discuss neuronal diseases associated with aberrance in the JIP family protein. Accumulating evidence suggests that chemical manipulation of lysosomal positioning may be a therapeutic approach for these neuronal diseases.
    Keywords:  JIP4; Parkinson's disease; autophagy; lysosomal positioning; lysosome; neurodegeneration; retrograde trafficking
    DOI:  https://doi.org/10.1002/bies.202300052
  14. J Cell Physiol. 2023 Aug 11.
    Transformed cells maintain survival by downregulating autophagy at a high cell confluency.
    Hye-Gyo Kim, Myeong-Han Ro, Sung-Hee Hwang, Michael Lee.
      Autophagy plays a dual role in tumorigenesis by functioning as both a tumor suppressor and promoter, depending on the stage of tumorigenesis. However, it is still unclear at what stage the role of autophagy changes during tumorigenesis. Herein, we investigated the differences in the basal levels and roles of autophagy in five cell lines at different stages of cell transformation. We found that cell lines at higher transformation stages were more sensitive to the autophagy inhibitors, suggesting that autophagy plays a more important role as the transformation progresses. Our ptfLC3 imaging analysis to measure Atg5/LC3-dependent autophagy showed increased autophagic flux in transformed cells compared to untransformed cells. However, the Cyto-ID analysis, which measures Atg5-dependent and -independent autophagic flux, showed high levels of autophagosome formation not only in the transformed cells but also in the initiated cell and Atg5 KO cell line. These results indicate that Atg5-independent autophagy may be more critical in initiated and transformed cell lines than in untransformed cells. Specially, we observed that transformed cells maintained relatively high basal autophagy levels under rapidly proliferating conditions but exhibited much lower basal autophagy levels at high confluency; however, autophagic flux was not significantly reduced in untransformed cells, even at high confluency. In addition, when continuously cultured for 3 weeks without passage, senescent cells were significantly less sensitive to autophagy inhibition than their actively proliferating counterparts. These results imply that once a cell has switched from a proliferative state to a senescent state, the inhibition of autophagy has only a minimal effect. Taken together, our results suggest that autophagy can be differentially regulated in cells at different stages of tumorigenesis under stressful conditions.
    Keywords:  Atg5; LC3; autophagy; cell transformation; downregulation; senescence
    DOI:  https://doi.org/10.1002/jcp.31098
  15. FEBS Lett. 2023 Aug 11.
    The role of the HORMA domain proteins ATG13 and ATG101 in initiating autophagosome biogenesis.
    Anh Nguyen, Alex C Faesen.
      Autophagy is a process of regulated degradation. It eliminates damaged and unnecessary cellular components by engulfing them with a de novo-generated organelle: the double-membrane autophagosome. The last three decades have provided us with a detailed parts list of the autophagy initiation machinery, have developed important insights into how these processes function and have identified regulatory proteins. It is now clear that autophagosome biogenesis requires the timely assembly of a complex machinery. However, it is unclear how a putative stable machine is assembled and disassembled, and how the different parts cooperate to perform its overall function. Although they have long been somewhat enigmatic in their precise role, HORMA domain proteins (first identified in Hop1p, Rev7p and MAD2 proteins) autophagy-related protein 13 (ATG13) and ATG101 of the ULK-kinase complex have emerged as important coordinators of the autophagy-initiating subcomplexes. Here, we will particularly focus on ATG13 and ATG101 and the role of their unusual metamorphosis in initiating autophagosome biogenesis. We will also explore how this metamorphosis could potentially be purposefully rate-limiting and speculate on how it could regulate the spontaneous self-assembly of the autophagy-initiating machinery.
    DOI:  https://doi.org/10.1002/1873-3468.14717
  16. Int J Mol Sci. 2023 Jul 25. pii: 11899. [Epub ahead of print]24(15):
    Dysregulation of Histone Deacetylases Inhibits Trophoblast Growth during Early Placental Development Partially through TFEB-Dependent Autophagy-Lysosomal Pathway.
    Peixin Wang, Chenqiong Zhao, Hanjing Zhou, Xiaona Huang, Hanqi Ying, Songying Zhang, Yibin Pan, Haiyan Zhu.
      Dysregulated biological behaviors of trophoblast cells can result in recurrent spontaneous abortion (RSA)-whose underlying etiology still remains insufficient. Autophagy, a conserved intracellular physiological process, is precisely monitored throughout whole pregnancy. Although the exact mechanism or role remains elusive, epigenetic modification has emerged as an important process. Herein, we found that a proportion of RSA patients exhibited higher levels of autophagy in villus tissues compared to controls, accompanied with impaired histone deacetylase (HDAC) expression. The purpose of this study is to explore the connection between HDACs and autophagy in the pathological course of RSA. Mechanistically, using human trophoblast cell models, treatment with HDAC inhibitor (HDACI)-trichostatin A (TSA) can induce autophagy by promoting nuclear translocation and transcriptional activity of the central autophagic regulator transcription factor EB (TFEB). Specifically, overactivated autophagy is involved in the TSA-driven growth inhibition of trophoblast, which can be partially reversed by the autophagy inhibitor chloroquine (CQ) or RNA interference of TFEB. In summary, our results reveal that abnormal acetylation and autophagy levels during early gestation may be associated with RSA and suggest the potential novel molecular target TFEB for RSA treatment.
    Keywords:  acetylation; autophagy; epigenetic modification; histone deacetylase inhibitor (HDACI); nuclear translocation; pathological course; recurrent spontaneous abortion; transcription factor EB
    DOI:  https://doi.org/10.3390/ijms241511899
  17. FEBS Lett. 2023 Aug 11.
    Autophagy as a caretaker of nuclear integrity.
    Emily Boyle, Florian Wilfling.
      Due to their essential functions, dysregulation of nuclear pore complexes (NPCs) is strongly associated with numerous human diseases, including neurodegeneration and cancer[1]. On a cellular level, longevity of scaffold nucleoporins in post-mitotic cells of both C. elegans and mammals renders them vulnerable to age-related damage, which is associated with an increase in pore leakiness and accumulation of intranuclear aggregates in rat brain cells[2-4]. Thus, understanding the mechanisms which underpin the homeostasis of this complex, as well as other nuclear proteins, is essential. In this review, autophagy-mediated degradation pathways governing nuclear components in yeast will be discussed, with a particular focus on NPCs. Furthermore, the various nuclear degradation mechanisms identified thus far in diverse eukaryotes will also be highlighted. This article is protected by copyright. All rights reserved.
    Keywords:  Atg39; NPC-phagy; Nup159; nuclear blebbing; nuclear lamina; nuclear pore complex; nuclear-derived vesicle; nucleophagy; quality control; selective autophagy
    DOI:  https://doi.org/10.1002/1873-3468.14719
  18. Autophagy. 2023 Aug 10.
    The small peptide VISP1 acts as a selective autophagy receptor regulating plant-virus interactions.
    Xin Tong, Jia-Jia Zhao, Ya-Lan Feng, Xian-Bing Wang.
      Selective macroautophagy/autophagy is tightly regulated by cargo receptors that recruit specific substrates to the ATG8-family proteins for autophagic degradation. Therefore, identification of selective receptors and their new cargoes will improve our understanding of selective autophagy functions in plant development and stress responses. We have recently demonstrated that the small peptide VISP1 acts as a selective autophagy receptor to mediate degradation of suppressors of RNA silencing (VSRs) of several RNA and DNA viruses. Moreover, VISP1 induces symptom recovery through fine-tuning the balance of plant immunity and virus pathogenicity. Our findings provide new insights into the double-edged sword roles of selective autophagy in plant-virus interactions.
    Keywords:  Plant-virus interactions; receptor; selective autophagy; small peptides; suppressors of RNA silencing
    DOI:  https://doi.org/10.1080/15548627.2023.2246858
  19. Cell Div. 2023 Aug 09. 18(1): 13
    The roles of METTL3 on autophagy and proliferation of vascular smooth muscle cells are mediated by mTOR rather than by CDK1.
    Hanshen Luo, Xingliang Wu, Bo Huo, Liyuan Liu, Ding-Sheng Jiang, Xin Yi.
       BACKGROUND: Aberrant proliferation of vascular smooth muscle cells (VSMCs) is the cause of neointima formation followed by vascular injury. Autophagy is involved in this pathological process, but its function is controversial. Recently, we found that methyltransferase like 3 (METTL3) inhibited VSMC proliferation by activating autophagosome formation. Moreover, we also demonstrated that METTL3 reduced the levels of phosphorylated mammalian target of rapamycin (p-mTOR) and cyclin dependent kinase 1 (p-CDK1/CDC2), which were critical for autophagy and proliferation regulation. However, whether mTOR and CDK1 mediated the function of METTL3 on autophagy and proliferation in VSMCs remains unknown.
    RESULTS: We showed that the activator of mTOR, MHY1485 largely reversed the effects of METTL3 overexpression on VSMC autophagy and proliferation. Rapamycin, the inhibitor of mTOR, obviously nullified the pro-proliferation effects of METTL3 knockdown by activating autophagy in VSMCs. Unexpectedly, mTOR did not contribute to the impacts of METTL3 on migration and phenotypic switching of VSMCs. On the other hand, by knockdown of CDK1 in VSMC with METTL3 deficiency, we demonstrated that CDK1 was involved in METTL3-regulated proliferation of VSMCs, but this effect was not mediated by autophagy.
    CONCLUSIONS: We concluded that mTOR but not CDK1 mediated the role of METTL3 on VSMC proliferation and autophagy.
    Keywords:  Autophagy; CDK1/CDC2; METTL3; Proliferation; Vascular smooth muscle cell; mTOR
    DOI:  https://doi.org/10.1186/s13008-023-00096-5
  20. Aging Cell. 2023 Aug 09. e13949
    Oculopharyngeal muscular dystrophy mutations link the RNA-binding protein HNRNPQ to autophagosome biogenesis.
    Hasan Ishtayeh, Margarita Galves, Tania T Barnatan, Yevgeny Berdichevsky, Fatima Amer-Sarsour, Metsada Pasmanik-Chor, Itzhak Braverman, Sergiu C Blumen, Avraham Ashkenazi.
      Autophagy is an intracellular degradative process with an important role in cellular homeostasis. Here, we show that the RNA binding protein (RBP), heterogeneous nuclear ribonucleoprotein Q (HNRNPQ)/SYNCRIP is required to stimulate early events in autophagosome biogenesis, in particular the induction of VPS34 kinase by ULK1-mediated beclin 1 phosphorylation. The RBPs HNRNPQ and poly(A) binding protein nuclear 1 (PABPN1) form a regulatory network that controls the turnover of distinct autophagy-related (ATG) proteins. We also show that oculopharyngeal muscular dystrophy (OPMD) mutations engender a switch from autophagosome stimulation to autophagosome inhibition by impairing PABPN1 and HNRNPQ control of the level of ULK1. The overexpression of HNRNPQ in OPMD patient-derived cells rescues the defective autophagy in these cells. Our data reveal a regulatory mechanism of autophagy induction that is compromised by PABPN1 disease mutations, and may thus further contribute to their deleterious effects.
    Keywords:  autophagy; autophagy genes; nutrient deprivation; trinucleotide repeat expansion
    DOI:  https://doi.org/10.1111/acel.13949
  21. Sci Total Environ. 2023 Aug 09. pii: S0048-9697(23)04792-7. [Epub ahead of print] 166167
    Cypermethrin induces endoplasmic reticulum stress and autophagy, leads to testicular dysfunction.
    Jiyeon Ham, Hyewon Jang, Gwonhwa Song, Whasun Lim.
      Cypermethrin is a pyrethroid insecticide that is used to control insects and protect crops. However, pesticide residues and their possible toxicity to non-target animals such as mammals are concerning. Although cypermethrin reduces testosterone levels, the molecular mechanisms involved, particularly those regarding endoplasmic reticulum (ER) stress and autophagy regulation, have not yet been fully elucidated. In this study, we demonstrated testicular toxicity of cypermethrin in mouse Leydig (TM3) and Sertoli (TM4) cells. Cypermethrin suppresses TM3 and TM4 cell proliferation and induces apoptosis. Moreover, it interrupted calcium homeostasis in intracellular organelles and dissipated mitochondrial membrane polarization in mouse testicular cells. Moreover, we verified the accumulation of Sqstm1/p62 protein in the mitochondria of cypermethrin-treated TM3 and TM4 cells. Furthermore, we confirmed that cypermethrin activated autophagy and the ER stress pathway in a time-dependent manner in both cell types. Finally, we determined that cypermethrin downregulated testicular function-related genes, steroidogenesis, and spermatogenesis in mouse testis cells. Therefore, we conclude that cypermethrin regulates autophagy and ER stress, leading to testicular dysfunction.
    Keywords:  Autophagy; Cypermethrin; ER stress; Mitochondria; Testis
    DOI:  https://doi.org/10.1016/j.scitotenv.2023.166167
  22. J Cell Physiol. 2023 Aug 11.
    TMEM175 downregulation participates in impairment of the autophagy related lysosomal dynamics following neonatal hypoxic-ischemic brain injury.
    Huiyi Zhang, Ye Tian, Weiwei Yu, Dongyi Tong, Yichen Ji, Xinrui Qu, Tianjiao Deng, Xinsheng Li, Ying Xu.
      The mechanism underlying long-term cognitive impairment caused by neonatal hypoxic-ischemic brain injury (HIBI) remains unclear. Autophagy is a closely related mechanism and may play a role in this process. We aimed to investigate the role of lysosomal transmembrane protein 175 (TMEM175) in the autophagy-lysosome pathway in neonatal rats with HIBI. A neonatal rat model of HIBI was established, hypoxia was induced, followed by left common carotid artery ligation. Expression levels of TMEM175 and the corresponding proteins involved in autophagy flux and the endolysosomal system fusion process were measured. Rats were administered TMEM175 plasmid via intracerebroventricular injection to induce overexpression. Brain damage and cognitive function were then assessed. TMEM175 was downregulated in the hippocampal tissue, and the autophagy-lysosome pathway was impaired following HIBI in neonatal rats. Overexpression of TMEM175 significantly mitigated neuronal injury and improved long-term cognitive and memory function in neonatal rats with HIBI. We found that improvement in the autophagy-lysosome pathway and endolysosomal system homeostasis, which are TMEM175 related, occurred via regulation of lysosomal membrane dynamic fusion. TMEM175 plays a critical role in maintaining the autophagy-lysosome pathway and endolysosomal homeostasis, contributing to the amelioration of neuronal injury and impaired long-term cognitive function following neonatal HIBI.
    Keywords:  TMEM175; autophagy-lysosome pathway; endolysosomal system; hypoxic-ischemic brain injury; membrane dynamics
    DOI:  https://doi.org/10.1002/jcp.31096
  23. World J Gastrointest Oncol. 2023 Jul 15. 15(7): 1135-1148
    Interaction mechanisms between autophagy and ferroptosis: Potential role in colorectal cancer.
    Xin-Ya Zeng, Xin-Ze Qiu, Jiang-Ni Wu, Sheng-Mei Liang, Jie-An Huang, Shi-Quan Liu.
      Colorectal cancer (CRC) is a common malignancy that has the second highest incidence and mortality rate. Although there are many personalized treatment options for CRC, the therapeutic effects are ultimately limited by drug resistance. Studies have aimed to block the initiation and progression of CRC by inducing cell death to overcome this obstacle. Substantial evidence has indicated that both autophagy and ferroptosis play important regulatory roles in CRC. Autophagy, a lysosome-dependent process by which cellular proteins and organelles are degraded, is the basic mechanism for maintaining cell homeostasis. The duality and complexity of autophagy in cancer therapy is a hot topic of discussion. Ferroptosis, a regulated cell death pathway, is associated with iron accumulation-induced lipid peroxidation. The activation of ferroptosis can suppress CRC proliferation, invasion and drug resistance. Furthermore, recent studies have suggested an interaction between autophagy and ferroptosis. Autophagy can selectively degrade certain cellular contents to provide raw materials for ferroptosis, ultimately achieving antitumor and anti-drug resistance. Therefore, exploring the interaction between autophagy and ferroptosis could reveal novel ideas for the treatment of CRC. In this review, we describe the mechanisms of autophagy and ferroptosis, focusing on their roles in CRC and the crosstalk between them.
    Keywords:  Autophagy; Cell death; Colorectal cancer; Ferroptosis; Iron; Lipid peroxidation
    DOI:  https://doi.org/10.4251/wjgo.v15.i7.1135
  24. Proc Natl Acad Sci U S A. 2023 08 15. 120(33): e2303010120
    Ezh2 promotes mammary tumor initiation through epigenetic regulation of the Wnt and mTORC1 signaling pathways.
    Linshan Liu, Bin Xiao, Alison Hirukawa, Harvey W Smith, Dongmei Zuo, Virginie Sanguin-Gendreau, Luke McCaffrey, Alice Jisoo Nam, William J Muller.
      The regulation of gene expression through histone posttranslational modifications plays a crucial role in breast cancer progression. However, the molecular mechanisms underlying the contribution of histone modification to tumor initiation remain unclear. To gain a deeper understanding of the role of the histone modifier Enhancer of Zeste homology 2 (Ezh2) in the early stages of mammary tumor progression, we employed an inducible mammary organoid system bearing conditional Ezh2 alleles that faithfully recapitulates key events of luminal B breast cancer initiation. We showed that the loss of Ezh2 severely impairs oncogene-induced organoid growth, with Ezh2-deficient organoids maintaining a polarized epithelial phenotype. Transcriptomic profiling showed that Ezh2-deficient mammary epithelial cells up-regulated the expression of negative regulators of Wnt signaling and down-regulated genes involved in mTORC1 (mechanistic target of rapamycin complex 1) signaling. We identified Sfrp1, a Wnt signaling suppressor, as an Ezh2 target gene that is derepressed and expressed in Ezh2-deficient epithelium. Furthermore, an analysis of breast cancer data revealed that Sfrp1 expression was associated with favorable clinical outcomes in luminal B breast cancer patients. Finally, we confirmed that targeting Ezh2 impairs mTORC1 activity through an indirect mechanism that up-regulates the expression of the tumor suppressor Pten. These findings indicate that Ezh2 integrates the mTORC1 and Wnt signaling pathways during early mammary tumor progression, arguing that inhibiting Ezh2 or therapeutically targeting Ezh2-dependent programs could be beneficial for the treatment of early-stage luminal B breast cancer.
    Keywords:  EZH2; Wnt signaling; breast cancer; mTOR signaling; tumor initiation
    DOI:  https://doi.org/10.1073/pnas.2303010120
  25. Autophagy. 2023 Aug 10.
    Targeting SARM1 improves autophagic stress-induced axonal neuropathy.
    Hye Ran Kim, Hye Jin Lee, Yewon Jeon, So Young Jang, Yoon Kyoung Shin, Jean Ho Yun, Hye Ji Park, Hyongjong Koh, Kyung Eun Lee, Jung Eun Shin, Hwan Tae Park.
      Macroautophagy/autophagy, a lysosome-dependent self-degradative process, is a critical mechanism for the clearance of misfolded proteins and dysfunctional organelles in neurons. In the peripheral nervous system, autophagic stress is associated with the development of peripheral neuropathy. However, the molecular mechanism of axonal neuropathy induced by autophagic stress due to dysfunction of autophagy in peripheral neurons in vivo is still unclear. We found that dorsal root ganglion (DRG) neuron-specific atg7 (autophagy related 7) knockout (atg7-cKO) mice employing two different Cre recombinase systems exhibited sensory neuropathy approximately 2 months after birth. In electron microscopy analysis, axon degeneration was clearly observed in the myelinated fibers of the sciatic nerve before the appearance of neuronal cell death. Dystrophic axons filled with abnormal vesicular accumulations and amorphous inclusions were specifically localized in the myelinated axons within the DRG in atg7-cKO mice, indicating the presence of autophagic stress in proximal axons. In line with the EM findings, the mutant mice showed preferential induction of axonal injury-associated genes, including ATF3 (activating transcription factor 3), in large-size DRG neurons that constitute myelinated fibers without axotomy. SARM1 (sterile alpha and HEAT/Armadillo motif containing 1), the central executioner of Wallerian degeneration, was activated in the sciatic nerves of atg7-cKO mice, and axonal degeneration and sensory neuropathy in atg7-cKO mice were prevented via expression of a dominant-negative Sarm1 transgene. Our findings demonstrate the importance of SARM1-dependent axon degeneration in the development of peripheral sensory neuropathy induced by impairment of autophagy.
    Keywords:  Activating transcription factor 3; Wallerian degeneration; autophagy; dorsal root ganglion; dystrophic axon; peripheral neuropathy
    DOI:  https://doi.org/10.1080/15548627.2023.2244861
  26. J Hazard Mater. 2023 Aug 07. pii: S0304-3894(23)01526-1. [Epub ahead of print]459 132243
    VPS41-mediated incomplete autophagy aggravates cadmium-induced apoptosis in mouse hepatocytes.
    Tao Wang, Lianqi Yan, Li Wang, Jian Sun, Huayi Qu, Yonggang Ma, Ruilong Song, Xishuai Tong, Jiaqiao Zhu, Yan Yuan, Jianhong Gu, Jianchun Bian, Zongping Liu, Hui Zou.
      Exposure to cadmium (Cd), an environmental heavy metal contaminant, is a serious threat to global health that increases the burden of liver diseases. Autophagy and apoptosis are important in Cd-induced liver injury. However, the regulatory mechanisms involved in the progression of Cd-induced liver damage are poorly understood. Herein, we investigated the role of vacuolar protein sorting 41 (VPS41) in Cd-induced autophagy and apoptosis in hepatocytes. We used targeted VPS41 regulation to elucidate the mechanism of Cd-induced hepatotoxicity. Our data showed that Cd triggered incomplete autophagy by downregulating VPS41, aggravating Cd-induced hepatocyte apoptosis. Mechanistically, Cd-induced VPS41 downregulation interfered with the mTORC1-TFEB/TFE3 axis, leading to an imbalance in autophagy initiation and termination and abnormal activation of autophagy. Moreover, Cd-induced downregulation of VPS41 inhibited autophagosome-lysosome fusion, leading to blocked autophagic flux. This triggers incomplete autophagy, which causes excessive P62 accumulation, accelerating Caspase-9 (CASP9) cleavage. Incomplete autophagy blocks clearance of cleaved CASP9 (CL-CASP9) via the autophagic pathway, promoting apoptosis. Notably, VPS41 overexpression alleviated Cd-induced incomplete autophagy and apoptosis, independent of the homotypic fusion and protein sorting complex. This study provides a new mechanistic understanding of the relationship between autophagy and apoptosis, suggesting that VPS41 is a new therapeutic target for Cd-induced liver damage.
    Keywords:  Cadmium; Incomplete autophagy; Liver damage; MTORC1-TFEB/TFE3 axis; VPS41
    DOI:  https://doi.org/10.1016/j.jhazmat.2023.132243
  27. Ann Clin Transl Neurol. 2023 Aug 06.
    Seizure reduction in TSC2-mutant mouse model by an mTOR catalytic inhibitor.
    Sameer C Dhamne, Meera E Modi, Audrey Gray, Simone Bonazzi, Lucas Craig, Elizabeth Bainbridge, Lahin Lalani, Chloe E Super, Samantha Schaeffer, Ketthsy Capre, Danuta Lubicka, Guiqing Liang, Doug Burdette, Stephanie M McTighe, Sarika Gurnani, Sheryl Anne D Vermudez, Daniel Curtis, Christopher J Wilson, Mustafa Q Hameed, Angelica D'Amore, Alexander Rotenberg, Mustafa Sahin.
       OBJECTIVE: Tuberous sclerosis complex (TSC) is a neurodevelopmental disorder caused by autosomal-dominant pathogenic variants in either the TSC1 or TSC2 gene, and it is characterized by hamartomas in multiple organs, such as skin, kidney, lung, and brain. These changes can result in epilepsy, learning disabilities, and behavioral complications, among others. The mechanistic link between TSC and the mechanistic target of the rapamycin (mTOR) pathway is well established, thus mTOR inhibitors can potentially be used to treat the clinical manifestations of the disorder, including epilepsy.
    METHODS: In this study, we tested the efficacy of a novel mTOR catalytic inhibitor (here named Tool Compound 1 or TC1) previously reported to be more brain-penetrant compared with other mTOR inhibitors. Using a well-characterized hypomorphic Tsc2 mouse model, which displays a translationally relevant seizure phenotype, we tested the efficacy of TC1.
    RESULTS: Our results show that chronic treatment with this novel mTOR catalytic inhibitor (TC1), which affects both the mTORC1 and mTORC2 signaling complexes, reduces seizure burden, and extends the survival of Tsc2 hypomorphic mice, restoring species typical weight gain over development.
    INTERPRETATION: Novel mTOR catalytic inhibitor TC1 exhibits a promising therapeutic option in the treatment of TSC.
    DOI:  https://doi.org/10.1002/acn3.51868
  28. Int J Mol Sci. 2023 Aug 01. pii: 12300. [Epub ahead of print]24(15):
    Interactome of Arabidopsis ATG5 Suggests Functions beyond Autophagy.
    Pernilla H Elander, Sanjana Holla, Igor Sabljić, Emilio Gutierrez-Beltran, Patrick Willems, Peter V Bozhkov, Elena A Minina.
      Autophagy is a catabolic pathway capable of degrading cellular components ranging from individual molecules to organelles. Autophagy helps cells cope with stress by removing superfluous or hazardous material. In a previous work, we demonstrated that transcriptional upregulation of two autophagy-related genes, ATG5 and ATG7, in Arabidopsis thaliana positively affected agronomically important traits: biomass, seed yield, tolerance to pathogens and oxidative stress. Although the occurrence of these traits correlated with enhanced autophagic activity, it is possible that autophagy-independent roles of ATG5 and ATG7 also contributed to the phenotypes. In this study, we employed affinity purification and LC-MS/MS to identify the interactome of wild-type ATG5 and its autophagy-inactive substitution mutant, ATG5K128R Here we present the first interactome of plant ATG5, encompassing not only known autophagy regulators but also stress-response factors, components of the ubiquitin-proteasome system, proteins involved in endomembrane trafficking, and potential partners of the nuclear fraction of ATG5. Furthermore, we discovered post-translational modifications, such as phosphorylation and acetylation present on ATG5 complex components that are likely to play regulatory functions. These results strongly indicate that plant ATG5 complex proteins have roles beyond autophagy itself, opening avenues for further investigations on the complex roles of autophagy in plant growth and stress responses.
    Keywords:  HXK1; PP2A; autophagy-unrelated functions; endomembrane trafficking; nuclear ATG12; nuclear ATG5; plant proteomics; plant ubiquitin-like conjugation system; posttranslational modifications; proteasome
    DOI:  https://doi.org/10.3390/ijms241512300
  29. Genes Dis. 2023 Nov;10(6): 2285-2295
    Potential relationship between autophagy and ferroptosis in myocardial ischemia/reperfusion injury.
    Yu Yang, Xianhe Lin.
      Autophagy is an evolutionarily conserved process involved in the degradation of long-lived proteins and excessive or dysfunctional organelles. As a pivotal cellular response, autophagy has been extensively studied and is known to be involved in various diseases. Ferroptosis is a recently discovered form of regulated cell death characterized by iron overload, leading to the accumulation of lethal levels of lipid hydroperoxides. Recently, an increasing number of studies have revealed a link between autophagy and ferroptosis. Myocardial ischemia/reperfusion injury (MIRI) is an urgent dilemma after myocardial infarction recanalization, which is regulated by several cell death pathways, including autophagy and ferroptosis. However, the potential relationship between autophagy and ferroptosis in MIRI remains unexplored. In this study, we briefly review the mechanisms of autophagy and ferroptosis, including their roles in MIRI. Moreover, we provide an overview of the potential crosstalk in MIRI. Clarifying the relationship between different cell death pathways may provide new ideas for the treatment of MIRI in the future.
    Keywords:  Autophagy; Ferroptosis; Iron overload; Myocardial ischemia/reperfusion injury; Relationship
    DOI:  https://doi.org/10.1016/j.gendis.2022.02.012
  30. Autophagy. 2023 Aug 10.
    Glial cells LAP axon fragments.
    Áron Szabó, Gábor Juhász.
      In the nervous system, dead cell-derived material arising from injuries and neurodegeneration is normally removed by the phagocytic activity of macrophages or glia. Failure in this process can lead to excessive inflammation and secondary neurodegeneration. During phagocytosis, engulfed material is captured into phagosomes. Maturation and subsequent fusion of these vesicles with lysosomes may utilize components of the macroautophagy pathway that has been referred to as LC3-associated phagocytosis or LAP for short.
    Keywords:  Drosophila; Glia; LC3-associated phagocytosis; autophagy; injury; neurodegeneration; neuron; phagocytosis
    DOI:  https://doi.org/10.1080/15548627.2023.2246355
  31. Invest Ophthalmol Vis Sci. 2023 08 01. 64(11): 10
    Impaired Lysosome Reformation in Chloroquine-Treated Retinal Pigment Epithelial Cells.
    M Helena Cardoso, Michael J Hall, Thomas Burgoyne, Pedro Fale, Tina Storm, Cristina Escrevente, Pedro Antas, Miguel C Seabra, Clare E Futter.
       Purpose: To model the in vivo effects of chloroquine on the retinal pigment epithelium in experimentally tractable cell culture systems and determine the effects of mild chloroquine treatment on lysosome function and turnover.
    Methods: Effects of low-dose chloroquine treatment on lysosomal function and accessibility to newly endocytosed cargo were investigated in primary and embryonic stem cell-derived RPE cells and ARPE19 cells using fluorescence and electron microscopy of fluorescent and gold-labeled probes. Lysosomal protein expression and accumulation were measured by quantitative PCR and Western blotting.
    Results: Initial chloroquine-induced lysosome neutralization was followed by partial recovery, lysosomal expansion, and accumulation of undegraded endocytic, phagocytic, and autophagic cargo and inhibition of cathepsin D processing. Accumulation of enlarged lysosomes was accompanied by a gradual loss of accessibility of these structures to the endocytic pathway, implying impaired lysosome reformation. Chloroquine-induced accumulation of pro-cathepsin D, as well as the lysosomal membrane protein, LAMP1, was reproduced by treatment with protease inhibitors and preceded changes in lysosomal gene expression.
    Conclusions: Low-dose chloroquine treatment inhibits lysosome reformation, causing a gradual depletion of lysosomes able to interact with cargo-carrying vacuoles and degrade their content. The resulting accumulation of newly synthesized pro-cathepsin D and LAMP1 reflects inhibition of normal turnover of lysosomal constituents and possibly lysosomes themselves. A better understanding of the mechanisms underlying lysosome reformation may reveal new targets for the treatment of chloroquine-induced retinopathy.
    DOI:  https://doi.org/10.1167/iovs.64.11.10
  32. Talanta. 2023 Aug 03. pii: S0039-9140(23)00779-8. [Epub ahead of print]266(Pt 1): 125028
    Unveiling the hypoxia-induced mitophagy process through two-channel real-time imaging of NTR and viscosity under the same excitation.
    Lei Wen, Mengqi Shao, Yinhui Li, Yanjun Zhang, Chao Peng, Huan Yu, Kai Zhang.
      Mitophagy is an essential physiological process that eliminates damaged mitochondria via lysosomes. It is reported that hypoxia, inflammatory stimuli or other stress conditions could lead to mitochondrial damage and mitochondrial dysfunction, which induces the process of mitophagy. Herein, we report a novel fluorescent probe PC-NTR for imaging hypoxia-induced mitophagy by monitoring the change of nitroreductase and viscosity simultaneously. To our delight, PC-NTR could respond simultaneously to nitroreductase and viscosity at different fluorescence channels with no mutual interference under the same excitation wavelength. The fluorescence emission around 535 nm was enhanced dramatically after addition of nitroreductase while the fluorescence emission around 635 nm heightened as the viscosity increased. The probe would be able to selectively targeting of mitochondria in cells because of the positively charged pyridine salt structure of PC-NTR. The probe was successfully applied to assess the different levels of hypoxia and real-time imaging of mitochondrial autophagy in live cells. More importantly, using dual channel imaging, PC-NTR could be used to distinguish cancer cells from normal cells and was successfully applied to imaging experiments in HeLa-derived tumor-bearing nude mice. Therefore, PC-NTR would be an important molecular tool for hypoxia imaging and detecting solid tumors in vivo.
    Keywords:  Fluorescence imaging; Hypoxia-induced mitophagy; NTR; Viscosity
    DOI:  https://doi.org/10.1016/j.talanta.2023.125028
  33. Cell Discov. 2023 Aug 08. 9(1): 84
    TET2 is required to suppress mTORC1 signaling through urea cycle with therapeutic potential.
    Jing He, Mingen Lin, Xinchao Zhang, Ruonan Zhang, Tongguan Tian, Yuefan Zhou, Wenjing Dong, Yajing Yang, Xue Sun, Yue Dai, Yue Xu, Zhenru Zhang, Ming Xu, Qun-Ying Lei, Yanping Xu, Lei Lv.
      Tumor development, involving both cell growth (mass accumulation) and cell proliferation, is a complex process governed by the interplay of multiple signaling pathways. TET2 mainly functions as a DNA dioxygenase, which modulates gene expression and biological functions via oxidation of 5mC in DNA, yet whether it plays a role in regulating cell growth remains unknown. Here we show that TET2 suppresses mTORC1 signaling, a major growth controller, to inhibit cell growth and promote autophagy. Mechanistically, TET2 functions as a 5mC "eraser" by mRNA oxidation, abolishes YBX1-HuR binding and promotes decay of urea cycle enzyme mRNAs, thus negatively regulating urea cycle and arginine production, which suppresses mTORC1 signaling. Therefore, TET2-deficient tumor cells are more sensitive to mTORC1 inhibition. Our results uncover a novel function for TET2 in suppressing mTORC1 signaling and inhibiting cell growth, linking TET2-mediated mRNA oxidation to cell metabolism and cell growth control. These findings demonstrate the potential of mTORC1 inhibition as a possible treatment for TET2-deficient tumors.
    DOI:  https://doi.org/10.1038/s41421-023-00567-7
  34. Cytokine. 2023 09;pii: S1043-4666(23)00195-3. [Epub ahead of print]169 156317
    SQSTM1 is a therapeutic target for infection and sterile inflammation.
    Daolin Tang, Rui Kang.
      Inflammation represents a fundamental immune response triggered by various detrimental stimuli, such as infections, tissue damage, toxins, and foreign substances. Protein degradation plays a crucial role in regulating the inflammatory process at multiple levels. The identification of sequestosome 1 (SQSTM1, also known as p62) protein as a binding partner of lymphocyte-specific protein tyrosine kinase in 1995 marked a significant milestone. Subsequent investigations unveiled the activity of SQSTM1 to interact with diverse unstructured substrates, including proteins, organelles, and pathogens, facilitating their delivery to the lysosome for autophagic degradation. In addition to its well-established intracellular functions, emerging studies have reported the active secretion or passive release of SQSTM1 by immune or non-immune cells, orchestrating the inflammatory responses. These distinct characteristics render SQSTM1 a critical therapeutic target in numerous human diseases, including infectious diseases, rheumatoid arthritis, inflammatory bowel disease, pancreatitis, asthma, chronic obstructive pulmonary disease, and cardiovascular diseases. This review provides a comprehensive overview of the structure and modulation of SQSTM1, discusses its intracellular and extracellular roles in inflammation, and highlights its significance in inflammation-related diseases. Future investigations focusing on elucidating the precise localization, structure, post-translational modifications of SQSTM1, as well as the identification of additional interacting partners, hold promise for unravelling further insights into the multifaceted functions of SQSTM1.
    Keywords:  Autophagy; Disease; Immunity; Infection; Inflammation; SQSTM1
    DOI:  https://doi.org/10.1016/j.cyto.2023.156317
  35. Int J Biol Sci. 2023 ;19(12): 3640-3660
    Protection of c-Fos from autophagic degradation by PRMT1-mediated methylation fosters gastric tumorigenesis.
    Eunji Kim, Laily Rahmawati, Nur Aziz, Han Gyung Kim, Ji Hye Kim, Kyung-Hee Kim, Byong Chul Yoo, Narayana Parameswaran, Jong-Sun Kang, Hoon Hur, Balachandran Manavalan, Jongsung Lee, Jae Youl Cho.
      Both AP-1 and PRMT1 are vital molecules in variety of cellular progresssion, but the interaction between these proteins in the context of cellular functions is less clear. Gastric cancer (GC) is one of the pernicious diseases worldwide. An in-depth understanding of the molecular mode of action underlying gastric tumorigenesis is still elusive. In this study, we found that PRMT1 directly interacts with c-Fos and enhances AP-1 activation. PRMT1-mediated arginine methylation (mono- and dimethylation) of c-Fos synergistically enhances c-Fos-mediated AP-1 liveliness and consequently increases c-Fos protein stabilization. Consistent with this finding, PRMT1 knockdown decreases the protein level of c-Fos. We discovered that the c-Fos protein undergoes autophagic degradation and found that PRMT1-mediated methylation at R287 protects c-Fos from autophagosomal degradation and is linked to clinicopathologic variables as well as prognosis in stomach tumor. Together, our data demonstrate that PRMT1-mediated c-Fos protein stabilization promotes gastric tumorigenesis. We contend that targeting this modification could constitute a new therapeutic strategy in gastric cancer.
    Keywords:  PRMT1; autophagy; c-Fos; gastric cancer; protein methylation; tumorigenesis
    DOI:  https://doi.org/10.7150/ijbs.85126
  36. Tissue Cell. 2023 Jul 31. pii: S0040-8166(23)00176-3. [Epub ahead of print]84 102188
    Pathological study of proximal tubule mitochondria in diclofenac-induced acute kidney injury model mice.
    Yuko Naya, Nozomi Hata, Miyu Kobayash, Momoka Thuyuki, Yuichi Koyama, Kikumi Ogihara.
      Diclofenac, a non-steroidal anti-inflammatory drug, reportedly targets mitochondria and induces nephrotoxicity via reactive oxygen species. However, there are few detailed reports of pathological analyses of mitochondria and the factors that cause acute kidney injury (AKI) as a result of nephrotoxicity. In this study, we investigated mitochondrial damage in the proximal tubule in AKI mice at 6, 12, and 24 h after administration of diclofenac. Statistical analysis of immunohistochemistry results confirmed that expression of p62 and LC3, which is associated with autophagy, reached a maximum level in the degenerated proximal renal tubule 12 h after diclofenac treatment, with high autophagy activity. Electron microscopy images provided clear evidence that confirmed mitochondrial degeneration and injury as well as autophagy (mitophagy) in mitochondria treated with diclofenac. The purpose of this study was to pathologically characterize both mitochondrial damage in the proximal renal tubules induced by diclofenac and the course of mitophagy to remove the damaged mitochondria. This report provides important information regarding mitochondrial damage in the proximal tubules in diclofenac-induced nephropathy.
    Keywords:  Acute kidney injury; Autophagy; Diclofenac; Transmission electron microscopy
    DOI:  https://doi.org/10.1016/j.tice.2023.102188
  37. NPJ Parkinsons Dis. 2023 Aug 08. 9(1): 120
    Parkinson's disease neurons exhibit alterations in mitochondrial quality control proteins.
    Chun Chen, David McDonald, Alasdair Blain, Emily Mossman, Kiera Atkin, Michael F Marusich, Roderick Capaldi, Laura Bone, Anna Smith, Andrew Filby, Daniel Erskine, Oliver Russell, Gavin Hudson, Amy E Vincent, Amy K Reeve.
      Mitochondrial dysfunction has been suggested to contribute to Parkinson's disease pathogenesis, though an understanding of the extent or exact mechanism of this contribution remains elusive. This has been complicated by challenging nature of pathway-based analysis and an inability simultaneously study multiple related proteins within human brain tissue. We used imaging mass cytometry (IMC) to overcome these challenges, measuring multiple protein targets, whilst retaining the spatial relationship between targets in post-mortem midbrain sections. We used IMC to simultaneously interrogate subunits of the mitochondrial oxidative phosphorylation complexes, and several key signalling pathways important for mitochondrial homoeostasis, in a large cohort of PD patient and control cases. We revealed a generalised and synergistic reduction in mitochondrial quality control proteins in dopaminergic neurons from Parkinson's patients. Further, protein-protein abundance relationships appeared significantly different between PD and disease control tissue. Our data showed a significant reduction in the abundance of PINK1, Parkin and phosphorylated ubiquitinSer65, integral to the mitophagy machinery; two mitochondrial chaperones, HSP60 and PHB1; and regulators of mitochondrial protein synthesis and the unfolded protein response, SIRT3 and TFAM. Further, SIRT3 and PINK1 did not show an adaptive response to an ATP synthase defect in the Parkinson's neurons. We also observed intraneuronal aggregates of phosphorylated ubiquitinSer65, alongside increased abundance of mitochondrial proteases, LONP1 and HTRA2, within the Parkinson's neurons with Lewy body pathology, compared to those without. Taken together, these findings suggest an inability to turnover mitochondria and maintain mitochondrial proteostasis in Parkinson's neurons. This may exacerbate the impact of oxidative phosphorylation defects and ageing related oxidative stress, leading to neuronal degeneration. Our data also suggest that that Lewy pathology may affect mitochondrial quality control regulation through the disturbance of mitophagy and intramitochondrial proteostasis.
    DOI:  https://doi.org/10.1038/s41531-023-00564-3
  38. Int J Mol Sci. 2023 Aug 01. pii: 12309. [Epub ahead of print]24(15):
    Natriuretic Peptide Signaling in Uterine Biology and Preeclampsia.
    Qingyu Wu.
      Endometrial decidualization is a uterine process essential for spiral artery remodeling, embryo implantation, and trophoblast invasion. Defects in endometrial decidualization and spiral artery remodeling are important contributing factors in preeclampsia, a major disorder in pregnancy. Atrial natriuretic peptide (ANP) is a cardiac hormone that regulates blood volume and pressure. ANP is also generated in non-cardiac tissues, such as the uterus and placenta. In recent human genome-wide association studies, multiple loci with genes involved in natriuretic peptide signaling are associated with gestational hypertension and preeclampsia. In cellular experiments and mouse models, uterine ANP has been shown to stimulate endometrial decidualization, increase TNF-related apoptosis-inducing ligand expression and secretion, and enhance apoptosis in arterial smooth muscle cells and endothelial cells. In placental trophoblasts, ANP stimulates adenosine 5'-monophosphate-activated protein kinase and the mammalian target of rapamycin complex 1 signaling, leading to autophagy inhibition and protein kinase N3 upregulation, thereby increasing trophoblast invasiveness. ANP deficiency impairs endometrial decidualization and spiral artery remodeling, causing a preeclampsia-like phenotype in mice. These findings indicate the importance of natriuretic peptide signaling in pregnancy. This review discusses the role of ANP in uterine biology and potential implications of impaired ANP signaling in preeclampsia.
    Keywords:  ANP; corin; endometrial decidualization; natriuretic peptides; preeclampsia; spiral artery remodeling
    DOI:  https://doi.org/10.3390/ijms241512309
  39. Cells. 2023 Aug 07. pii: 2014. [Epub ahead of print]12(15):
    Implication of mTOR Signaling in NSCLC: Mechanisms and Therapeutic Perspectives.
    Antonios N Gargalionis, Kostas A Papavassiliou, Athanasios G Papavassiliou.
      Mechanistic target of the rapamycin (mTOR) signaling pathway represents a central cellular kinase that controls cell survival and metabolism. Increased mTOR activation, along with upregulation of respective upstream and downstream signaling components, have been established as oncogenic features in cancer cells in various tumor types. Nevertheless, mTOR pathway therapeutic targeting has been proven to be quite challenging in various clinical settings. Non-small cell lung cancer (NSCLC) is a frequent type of solid tumor in both genders, where aberrant regulation of the mTOR pathway contributes to the development of oncogenesis, apoptosis resistance, angiogenesis, cancer progression, and metastasis. In this context, the outcome of mTOR pathway targeting in clinical trials still demonstrates unsatisfactory results. Herewith, we discuss recent findings regarding the mechanisms and therapeutic targeting of mTOR signaling networks in NSCLC, as well as future perspectives for the efficient application of treatments against mTOR and related protein molecules.
    Keywords:  Akt; PI3K; mTOR signaling; non-small cell lung cancer (NSCLC); rapamycin
    DOI:  https://doi.org/10.3390/cells12152014
  40. Nat Commun. 2023 08 08. 14(1): 4769
    Autophagy promotes jasmonate-mediated defense against nematodes.
    Jinping Zou, Xinlin Chen, Chenxu Liu, Mingyue Guo, Mukesh Kumar Kanwar, Zhenyu Qi, Ping Yang, Guanghui Wang, Yan Bao, Diane C Bassham, Jingquan Yu, Jie Zhou.
      Autophagy, as an intracellular degradation system, plays a critical role in plant immunity. However, the involvement of autophagy in the plant immune system and its function in plant nematode resistance are largely unknown. Here, we show that root-knot nematode (RKN; Meloidogyne incognita) infection induces autophagy in tomato (Solanum lycopersicum) and different atg mutants exhibit high sensitivity to RKNs. The jasmonate (JA) signaling negative regulators JASMONATE-ASSOCIATED MYC2-LIKE 1 (JAM1), JAM2 and JAM3 interact with ATG8s via an ATG8-interacting motif (AIM), and JAM1 is degraded by autophagy during RKN infection. JAM1 impairs the formation of a transcriptional activation complex between ETHYLENE RESPONSE FACTOR 1 (ERF1) and MEDIATOR 25 (MED25) and interferes with transcriptional regulation of JA-mediated defense-related genes by ERF1. Furthermore, ERF1 acts in a positive feedback loop and regulates autophagy activity by transcriptionally activating ATG expression in response to RKN infection. Therefore, autophagy promotes JA-mediated defense against RKNs via forming a positive feedback circuit in the degradation of JAMs and transcriptional activation by ERF1.
    DOI:  https://doi.org/10.1038/s41467-023-40472-x
  41. Cell Rep. 2023 Aug 04. pii: S2211-1247(23)00954-3. [Epub ahead of print]42(8): 112943
    Autophagy collaborates with apoptosis pathways to control oligodendrocyte number.
    Tingxin Zhang, Aksheev Bhambri, Yihe Zhang, Daniela Barbosa, Han-Gyu Bae, Jumin Xue, Sabeen Wazir, Sara B Mulinyawe, Jun Hee Kim, Lu O Sun.
      Oligodendrocytes are the sole myelin-producing cells in the central nervous system. Oligodendrocyte number is tightly controlled across diverse brain regions to match local axon type and number, yet the underlying mechanisms remain unclear. Here, we show that autophagy, an evolutionarily conserved cellular process that promotes cell survival under physiological conditions, elicits premyelinating oligodendrocyte apoptosis during development. Autophagy flux is increased in premyelinating oligodendrocytes, and its genetic blockage causes ectopic oligodendrocyte survival throughout the entire brain. Autophagy functions cell autonomously in the premyelinating oligodendrocyte to trigger cell apoptosis, and it genetically interacts with the TFEB pathway to limit oligodendrocyte number across diverse brain regions. Our results provide in vivo evidence showing that autophagy promotes apoptosis in mammalian cells under physiological conditions and reveal key intrinsic mechanisms governing oligodendrogenesis.
    Keywords:  CP: Developmental biology; CP: Neuroscience; apoptosis; autophagy; central nervous system; myelination; oligodendrocyte
    DOI:  https://doi.org/10.1016/j.celrep.2023.112943
  42. Int J Mol Sci. 2023 Aug 05. pii: 12481. [Epub ahead of print]24(15):
    From Acid Alpha-Glucosidase Deficiency to Autophagy: Understanding the Bases of POMPE Disease.
    Valentina Sánchez-Porras, Johana Maria Guevara-Morales, Olga Yaneth Echeverri-Peña.
      Pompe disease (PD) is caused by mutations in the GAA gene, which encodes the lysosomal enzyme acid alpha-glucosidase, causing lysosomal glycogen accumulation, mainly in muscular tissue. Autophagic buildup is considered the main factor affecting skeletal muscle, although other processes are also involved. Uncovering how these mechanisms are interconnected could be an approximation to address long-lasting concerns, like the differential skeletal and cardiac involvement in each clinical phenotype. In this sense, a network reconstruction based on a comprehensive literature review of evidence found in PD enriched with the STRING database and other scientific articles is presented. The role of autophagic lysosome reformation, PGC-1α, MCOLN1, calcineurin, and Keap1 as intermediates between the events involved in the pathologic cascade is discussed and contextualized within their relationship with mTORC1/AMPK. The intermediates and mechanisms found open the possibility of new hypotheses and questions that can be addressed in future experimental studies of PD.
    Keywords:  Pompe disease; acid alpha-glucosidase; autophagy; glycogen storage disease type II; interaction network
    DOI:  https://doi.org/10.3390/ijms241512481
  43. Mol Neurobiol. 2023 Aug 05.
    Metformin and Trehalose-Modulated Autophagy Exerts a Neurotherapeutic Effect on Parkinson's Disease.
    Yareth Gopar-Cuevas, Odila Saucedo-Cardenas, Maria J Loera-Arias, Roberto Montes-de-Oca-Luna, Humberto Rodriguez-Rocha, Aracely Garcia-Garcia.
      Since the number of aged people will increase in the next years, neurodegenerative diseases, including Parkinson's Disease (PD), will also rise. Recently, we demonstrated that autophagy stimulation with rapamycin decreases dopaminergic neuronal death mediated by oxidative stress in the paraquat (PQ)-induced PD model. Assessing the neurotherapeutic efficacy of autophagy-inducing molecules is critical for preventing or delaying neurodegeneration. Therefore, we evaluated the autophagy inducers metformin and trehalose effect in a PD model. Autophagy induced by both molecules was confirmed in the SH-SY5Y dopaminergic cells by detecting increased LC3-II marker and autophagosome number compared to the control by western blot and transmission electron microscopy. Both autophagy inducers showed an antioxidant effect, improved mitochondrial activity, and decreased dopaminergic cell death induced by PQ. Next, we evaluated the effect of both inducers in vivo. C57BL6 mice were pretreated with metformin or trehalose before PQ administration. Cognitive and motor deteriorated functions in the PD model were evaluated through the nest building and the gait tests and were prevented by metformin and trehalose. Both autophagy inducers significantly reduced the dopaminergic neuronal loss, astrocytosis, and microgliosis induced by PQ. Also, cell death mediated by PQ was prevented by metformin and trehalose, assessed by TUNEL assay. Metformin and trehalose induced autophagy through AMPK phosphorylation and decreased α-synuclein accumulation. Therefore, metformin and trehalose are promising neurotherapeutic autophagy inducers with great potential for treating neurodegenerative diseases such as PD.
    Keywords:  Autophagy; Dopaminergic neurons; Metformin; Paraquat; Parkinson’s disease; Trehalose
    DOI:  https://doi.org/10.1007/s12035-023-03530-5
  44. Mol Neurodegener. 2023 Aug 10. 18(1): 54
    TMEM106B aggregation in neurodegenerative diseases: linking genetics to function.
    Hai-Shan Jiao, Peng Yuan, Jin-Tai Yu.
       BACKGROUND: Mutations of the gene TMEM106B are risk factors for diverse neurodegenerative diseases. Previous understanding of the underlying mechanism focused on the impairment of lysosome biogenesis caused by TMEM106B loss-of-function. However, mutations in TMEM106B increase its expression level, thus the molecular process linking these mutations to the apparent disruption in TMEM106B function remains mysterious.
    MAIN BODY: Recent new studies reported that TMEM106B proteins form intracellular amyloid filaments which universally exist in various neurodegenerative diseases, sometimes being the dominant form of protein aggregation. In light of these new findings, in this review we systematically examined previous efforts in understanding the function of TMEM106B in physiological and pathological conditions. We propose that TMEM106B aggregations could recruit normal TMEM106B proteins and interfere with their function.
    CONCLUSIONS: TMEM106B mutations could lead to lysosome dysfunction by promoting the aggregation of TMEM106B and reducing these aggregations may restore lysosomal function, providing a potential therapeutic target for various neurodegenerative diseases.
    Keywords:  Aggregation; Amyloid fibrils; Lysosome; Neurodegeneration; TMEM106B; Therapeutics
    DOI:  https://doi.org/10.1186/s13024-023-00644-1
  45. Cell Death Dis. 2023 08 05. 14(8): 505
    The ubiquitin ligase TRIM32 promotes the autophagic response to Mycobacterium tuberculosis infection in macrophages.
    Alessandra Romagnoli, Martina Di Rienzo, Elisa Petruccioli, Carmela Fusco, Ivana Palucci, Lucia Micale, Tommaso Mazza, Giovanni Delogu, Giuseppe Merla, Delia Goletti, Mauro Piacentini, Gian Maria Fimia.
      Mycobacterium tuberculosis (Mtb) is known to evade host immune responses and persist in macrophages for long periods. A mechanism that the host uses to combat Mtb is xenophagy, a selective form of autophagy that targets intracellular pathogens for degradation. Ubiquitination of Mtb or Mtb-containing compartments is a key event to recruit the autophagy machinery and mediate the bacterial delivery to the lysosome. This event relies on the coordinated and complementary activity of different ubiquitin ligases, including PARKIN, SMURF1, and TRIM16. Because each of these factors is responsible for the ubiquitination of a subset of the Mtb population, it is likely that additional ubiquitin ligases are employed by macrophages to trigger a full xenophagic response during Mtb infection. In this study, we investigated the role TRIM proteins whose expression is modulated in response to Mtb or BCG infection of primary macrophages. These TRIMs were ectopically expressed in THP1 macrophage cell line to assess their impact on Mtb replication. This screening identified TRIM32 as a novel player involved in the intracellular response to Mtb infection, which promotes autophagy-mediated Mtb degradation. The role of TRIM32 in xenophagy was further confirmed by silencing TRIM32 expression in THP1 cells, which causes increased intracellular growth of Mtb associated to impaired Mtb ubiquitination, reduced recruitment of the autophagy proteins NDP52/CALCOCO2 and BECLIN 1/BECN1 to Mtb and autophagosome formation. Overall, these findings suggest that TRIM32 plays an important role in the host response to Mtb infection through the induction of autophagy, representing a promising target for host-directed tuberculosis therapies.
    DOI:  https://doi.org/10.1038/s41419-023-06026-1
  46. Nat Cell Biol. 2023 Aug 10.
    Malonyl-CoA links lipid metabolism to nutrient signalling by directly inhibiting mTORC1.
      
    DOI:  https://doi.org/10.1038/s41556-023-01206-9
  47. Cells. 2023 Jul 25. pii: 1924. [Epub ahead of print]12(15):
    High BECN1 Expression Negatively Correlates with BCL2 Expression and Predicts Better Prognosis in Diffuse Large B-Cell Lymphoma: Role of Autophagy.
    Amreen Salwa, Alessandra Ferraresi, Eleonora Secomandi, Letizia Vallino, Riccardo Moia, Andrea Patriarca, Beatrice Garavaglia, Gianluca Gaidano, Ciro Isidoro.
      Diffuse large B-cell lymphoma (DLBCL) is characterized by high molecular and clinical heterogeneity. Autophagy, a lysosome-driven catabolic process devoted to macromolecular turnover, is fundamental in maintaining normal hematopoietic stem cells and progenitors homeostasis, and its dysregulation plays a critical role in the initiation and progression of hematological malignancies. One main regulator of autophagy is BECLIN-1, which may interact alternatively with either BCL-2, thus allowing apoptosis, or PI3KC3, thus promoting autophagy. The altered expression of BCL2 and BECN1 correlates with lymphoma outcomes, but whether this is associated with dysregulated cross-talk between autophagy and apoptosis remains to be elucidated. Analysis of the TCGA database revealed that BCL2 and BECN1 mRNA expression were inversely correlated in DLBCL patients. In representative DLBCL cell lines exposed to doxorubicin, the cells highly expressing BCL-2 were resistant, while the ones highly expressing BECLIN-1 were sensitive, and this correlated with low and high autophagy flux, respectively. Venetoclax targeting of BCL-2 increased while the spautin-1-mediated inhibition of BECLIN-1-dependent autophagy reversed doxorubicin sensitivity in the former and in the latter, respectively. By interrogating the TCGA DLBCL dataset, we found that BCL2 and BECN1 acted as negative and positive prognostic markers for DLBCL, respectively. The differentially expressed gene analysis in the respective cohorts revealed that BCL2 positively correlated with oncogenic pathways (e.g., glucose transport, HIF1A signaling, JAK-STAT signaling, PI3K-AKT-mTOR pathway) and negatively correlated with autophagy-related transcripts, while BECN1 showed the opposite trend. Notably, patients with high BECN1 expression displayed longer survival. Our data reveal, for the first time, that the modulation of BECLIN-1-dependent autophagy influences the prognosis of DLBCL patients and provide a mechanistic explanation supporting the therapeutic use of drugs that, by stimulating autophagy, can sensitize lymphoma cells to chemotherapy.
    Keywords:  BCL-2; BECLIN-1; TCGA; apoptosis; autophagy; chemoresistance; chemotherapy; lymphoma; overall survival; prognosis; venetoclax
    DOI:  https://doi.org/10.3390/cells12151924
  48. J Cell Biochem. 2023 Aug 11.
    Rab44 negatively regulates myoblast differentiation by controlling fusogenic protein transport and mTORC1 signaling.
    Ayuko Tanimoto, Yu Yamaguchi, Tomoko Kadowaki, Eiko Sakai, Shun Oyakawa, Yusuke Ono, Noriaki Yoshida, Takayuki Tsukuba.
      Skeletal muscle is composed of multinucleated myotubes formed by the fusion of mononucleated myoblasts. Skeletal muscle differentiation, termed as myogenesis, have been investigated using the mouse skeletal myoblast cell line C2C12. It has been reported that several "small" Rab proteins, major membrane-trafficking regulators, possibly regulate membrane protein transport in C2C12 cells; however, the role of Rab proteins in myogenesis remains unexplored. Rab44, a member of "large" Rab GTPases, has recently been identified as a negative regulator of osteoclast differentiation. In this study, using C2C12 cells, we found that Rab44 expression was upregulated during myoblast differentiation into myotubes. Knockdown of Rab44 enhanced myoblast differentiation and myotube formation. Consistent with these results, Rab44 knockdown in myoblasts increased expression levels of several myogenic marker genes. Rab44 knockdown increased the surface accumulation of myomaker and myomixer, two fusogenic proteins required for multinucleation, implying enhanced cell fusion. Conversely, Rab44 overexpression inhibited myoblast differentiation and tube formation, accompanied by decreased expression of some myogenic markers. Furthermore, Rab44 was found to be predominantly localized in lysosomes, and Rab44 overexpression altered the number and size of lysosomes. Considering the underlying molecular mechanism, Rab44 overexpression impaired the signaling pathway of the mechanistic target of rapamycin complex1 (mTORC1) in C2C12 cells. Namely, phosphorylation levels of mTORC1 and downstream mTORC1 substrates, such as S6 and P70-S6K, were notably lower in Rab44 overexpressing cells than those in control cells. These results indicate that Rab44 negatively regulates myoblast differentiation into myotubes by controlling fusogenic protein transport and mTORC1 signaling.
    Keywords:  C2C12 cells; Rab GTPase; Rab44; myoblast differentiation; myogenesis
    DOI:  https://doi.org/10.1002/jcb.30457
  49. Pharmacol Res. 2023 Aug 05. pii: S1043-6618(23)00240-2. [Epub ahead of print] 106884
    Paradigm shift in the treatment of tuberous sclerosis: effectiveness of everolimus.
    Roberto Previtali, Giorgia Prontera, Enrico Alfei, Luisa Nespoli, Silvia Masnada, Pierangelo Veggiotti, Savina Mannarino.
      Tuberous sclerosis complex is an autosomal dominant disease characterised by abnormal cell proliferation and differentiation that affects multiple organs and can lead to the growth of hamartomas. Tuberous sclerosis complex is caused by the disinhibition of the protein mTOR (mammalian target of rapamycin). In the past, various therapeutic approaches, even if only symptomatic, have been attempted to improve the clinical effects of this disease. While all of these therapeutic strategies are useful and are still used and indicated, they are symptomatic therapies based on the individual symptoms of the disease and therefore not fully effective in modifying long-term outcomes. A new therapeutic approach is the introduction of allosteric inhibitors of mTORC1, which allow restoration of metabolic homeostasis in mutant cells, potentially eliminating most of the clinical manifestations associated with Tuberous sclerosis complex. Everolimus, a mammalian target of the rapamycin inhibitor, is able to reduce hamartomas, correcting the specific molecular defect that causes Tuberous sclerosis complex. In this review, we report the findings from the literature on the use of everolimus as an effective and safe drug in the treatment of TSC manifestations affecting various organs, from the central nervous system to the heart.
    Keywords:  Tuberous sclerosis complex; angiomyolipoma; astrocytomas; cardiac rhabdomyomas; everolimus; mTOR inibitors
    DOI:  https://doi.org/10.1016/j.phrs.2023.106884
  50. Cells. 2023 Jul 30. pii: 1969. [Epub ahead of print]12(15):
    The Role of Mitophagy in Glaucomatous Neurodegeneration.
    Dimitrios Stavropoulos, Manjot K Grewal, Bledi Petriti, Kai-Yin Chau, Christopher J Hammond, David F Garway-Heath, Gerassimos Lascaratos.
      This review aims to provide a better understanding of the emerging role of mitophagy in glaucomatous neurodegeneration, which is the primary cause of irreversible blindness worldwide. Increasing evidence from genetic and other experimental studies suggests that mitophagy-related genes are implicated in the pathogenesis of glaucoma in various populations. The association between polymorphisms in these genes and increased risk of glaucoma is presented. Reduction in intraocular pressure (IOP) is currently the only modifiable risk factor for glaucoma, while clinical trials highlight the inadequacy of IOP-lowering therapeutic approaches to prevent sight loss in many glaucoma patients. Mitochondrial dysfunction is thought to increase the susceptibility of retinal ganglion cells (RGCs) to other risk factors and is implicated in glaucomatous degeneration. Mitophagy holds a vital role in mitochondrial quality control processes, and the current review explores the mitophagy-related pathways which may be linked to glaucoma and their therapeutic potential.
    Keywords:  genetics; glaucoma; glaucomatous neurodegeneration; mitochondria; mitochondrial dysfunction; mitophagy; primary open-angle glaucoma
    DOI:  https://doi.org/10.3390/cells12151969
  51. J Cell Physiol. 2023 Aug 11.
    CircHIPK3 contributes to cisplatin resistance in gastric cancer by blocking autophagy-dependent ferroptosis.
    Ziqi Shang, Zhengdong Luo, Yifeng Wang, Qi Liu, Yiwei Xin, Mengjiao Zhang, Xinyang Li, Shunjie Zeng, Longchen Yu, Xin Zhang, Yi Zhang.
      Cisplatin is the first-line chemotherapy for gastric cancer (GC). However, its efficacy is dampened by the development of chemoresistance, which leads to poor prognosis in GC patients. Recently, evidence has revealed that circular RNAs (circRNAs) and dysregulation of autophagy-dependent ferroptosis play critical roles in cancer chemoresistance. Herein, for the first time we report that circHIPK3 has a vital role in GC cisplatin resistance. CircHIPK3 regulated cisplatin resistance by targeting autophagy and ferroptosis. In brief, knockdown circHIPK3 decreased GC cell cisplatin resistance by enhancing ferroptosis via the miR-508-3p/Bcl-2/beclin1/SLC7A11 axis. Taken together, our results demonstrate that ferroptosis is a promising strategy to ameliorate cisplatin resistance. Importantly, serum exosomal circHIPK3 could also be a noninvasive indicator to evaluate cisplatin resistance in GC.
    Keywords:  autophagy; circHIPK3; cisplatin resistance; ferroptosis; gastric cancer
    DOI:  https://doi.org/10.1002/jcp.31093
  52. Int J Mol Sci. 2023 Jul 27. pii: 12052. [Epub ahead of print]24(15):
    Autophagy Inhibition via Hydroxychloroquine or 3-Methyladenine Enhances Chemotherapy-Induced Apoptosis in Neuro-Blastoma and Glioblastoma.
    Darcy Wear, Eesha Bhagirath, Arpana Balachandar, Caleb Vegh, Siyaram Pandey.
      Neuroblastoma is the most common tumour in children under 1 year old, accounting for 12-15% of childhood cancer deaths. Although current treatments are relatively efficacious against this cancer, associated adverse effects could be detrimental to growth and development. In contrast, glioblastoma accounts for 52% of brain tumours and has an extremely poor prognosis. Current chemotherapeutics include temozolomide, which has numerous negative side-effects and a low-effective rate. Previous studies have shown the manipulation of autophagy to be a promising method for targeting cancers, including glioblastoma. We sought to determine the effects of autophagic alterations in combination with current chemotherapies in both neuroblastoma and glioblastoma. Supplementing cisplatin or temozolomide with autophagy activator rapamycin stabilized cancer cell mitochondria, despite having little effect on apoptosis or oxidative stress. Autophagy inhibition via 3-methyladenine or hydroxychloroquine alongside standard chemotherapies enhanced apoptosis and oxidative stress, with 3-methyladenine also disrupting mitochondrial health. Importantly, combining hydroxychloroquine with 0.5 µM cisplatin or 50 µg/mL temozolomide was as or more effective than 2 µM cisplatin or 100 µg/mL temozolomide alone. Analyzing these interesting results, a combined treatment of autophagy inhibitor with a standard chemotherapeutic agent could help to improve patient prognosis and reduce chemotherapy doses and their associated side-effects.
    Keywords:  autophagy; cancer; chemotherapy; homeostasis; hydroxychloroquine; mitochondria; oxidative stress; rapamycin; therapeutics
    DOI:  https://doi.org/10.3390/ijms241512052
  53. Gynecol Endocrinol. 2023 Dec;39(1): 2242962
    Autophagy-dependent ferroptosis is involved in the development of endometriosis.
    Hui Li, Huadi Yang, Shenyi Lu, Xinyan Wang, Xinhe Shi, Peiyu Mao.
       OBJECTIVE: Endometriosis (EMS) is an estrogen-dependent condition with unclear pathogenesis. Recent findings suggest implicate autophagy and ferroptosis in EMS development.
    METHODS: We assessed autophagy and ferroptosis proteins in EMS patients using immunohistochemistry and western blot and established an EMS rat model through allograft endometrial transplantation, confirmed via hematoxylin and eosin staining and epithelial-mesenchymal transition -related proteins. Primary EMS cells were isolated from the model rats and cultured under five conditions: control, EMS, EMS with Rapamycin (autophagy inducer), EMS with si-Atg5 (autophagy inhibitor), and EMS with si-Atg5 plus Erastin (ferroptosis inducer). We evaluated cell viability, iron content, oxidative stress, and mitochondrial morphologyin EMS cells, and detected autophagy and ferroptosis proteins through immunofluorescence, western blot, and monodansylcadaverine staining.
    RESULTS: Autophagy proteins Beclin1 and LC3 were highly expressed, whereas p62, glutathione peroxidase 4, and p53 were lowly expressed in EMS patients. Rapamycin decreased cell viability but increased iron content, reactive oxygen species, lipid peroxide production, the number of ferroptotic mitochondria, and the expression of autophagy proteins in EMS cells, while si-Atg5 showed opposite effects. Additionally, Erastin reversed the impact of si-Atg5 on EMS cells.
    CONCLUSION: Our findings suggest that autophagy-dependent ferroptosis plays a role in EMS progression.
    Keywords:  Autophagy; endometriosis; ferroptosis
    DOI:  https://doi.org/10.1080/09513590.2023.2242962
  54. Cell Death Differ. 2023 Aug 11.
    FBXL4 mutations cause excessive mitophagy via BNIP3/BNIP3L accumulation leading to mitochondrial DNA depletion syndrome.
    Yingji Chen, Dongyue Jiao, Yang Liu, Xiayun Xu, Yilin Wang, Xiaona Luo, Hexige Saiyin, Yao Li, Kun Gao, Yucai Chen, Shi-Min Zhao, Lixiang Ma, Chenji Wang.
      Mitochondria are essential organelles found in eukaryotic cells that play a crucial role in ATP production through oxidative phosphorylation (OXPHOS). Mitochondrial DNA depletion syndrome (MTDPS) is a group of genetic disorders characterized by the reduction of mtDNA copy number, leading to deficiencies in OXPHOS and mitochondrial functions. Mutations in FBXL4, a substrate-binding adaptor of Cullin 1-RING ubiquitin ligase complex (CRL1), are associated with MTDPS, type 13 (MTDPS13). Here, we demonstrate that, FBXL4 directly interacts with the mitophagy cargo receptors BNIP3 and BNIP3L, promoting their degradation through the ubiquitin-proteasome pathway via the assembly of an active CRL1FBXL4 complex. However, MTDPS13-associated FBXL4 mutations impair the assembly of an active CRL1FBXL4 complex. This results in a notable accumulation of BNIP3/3L proteins and robust mitophagy even at basal levels. Excessive mitophagy was observed in Knockin (KI) mice carrying a patient-derived FBXL4 mutation and cortical neurons (CNs)-induced from MTDPS13 patient human induced pluripotent stem cells (hiPSCs). In summary, our findings suggest that abnormal activation of BNIP3/BNIP3L-dependent mitophagy impairs mitochondrial homeostasis and underlies FBXL4-mutated MTDPS13.
    DOI:  https://doi.org/10.1038/s41418-023-01205-1
  55. J Cell Physiol. 2023 Aug 10.
    Rab44 deficiency accelerates recovery from muscle damage by regulating mTORC1 signaling and transport of fusogenic regulators.
    Shun Oyakawa, Yu Yamaguchi, Tomoko Kadowaki, Eiko Sakai, Mayuko Noguromi, Ayuko Tanimoto, Yusuke Ono, Hiroshi Murata, Takayuki Tsukuba.
      The skeletal muscle is a tissue that shows remarkable plasticity to adapt to various stimuli. The development and regeneration of skeletal muscles are regulated by numerous molecules. Among these, we focused on Rab44, a large Rab GTPase, that has been recently identified in immune cells and osteoclasts. Recently, bioinformatics data has revealed that Rab44 is upregulated during the myogenic differentiation of myoblasts into myotubes in C2C12 cells. Thus, Rab44 may be involved in myogenesis. Here, we have investigated the effects of Rab44 deficiency on the development and regeneration of skeletal muscle in Rab44 knockout (KO) mice. Although KO mice exhibited body and muscle weights similar to those of wild-type (WT) mice, the histochemical analysis showed that the myofiber cross-sectional area (CSA) of KO mice was significantly smaller than that of WT mice. Importantly, the results of muscle regeneration experiments using cardiotoxin revealed that the CSA of KO mice was significantly larger than that of WT mice, suggesting that Rab44 deficiency promotes muscle regeneration. Consistent with the in vivo results, in vitro experiments indicated that satellite cells derived from KO mice displayed enhanced proliferation and differentiation. Mechanistically, KO satellite cells exhibited an increased mechanistic target of rapamycin complex 1 (mTORC1) signaling compared to WT cells. Additionally, enhanced cell surface transport of myomaker and myomixer, which are essential membrane proteins for myoblast fusion, was observed in KO satellite cells compared to WT cells. Therefore, Rab44 deficiency enhances muscle regeneration by modulating the mTORC1 signaling pathway and transport of fusogenic regulators.
    Keywords:  Rab GTPase; Rab44; myofiber cross-sectional area; satellite cells; skeletal muscle
    DOI:  https://doi.org/10.1002/jcp.31082
  56. Glia. 2023 Aug 12.
    TUNEL-positive structures in activated microglia and SQSTM1/p62-positive structures in activated astrocytes in the neurodegenerative brain of a CLN10 mouse model.
    Shun Mitsui, Junji Yamaguchi, Chigure Suzuki, Yasuo Uchiyama, Isei Tanida.
      Neuronal ceroid lipofuscinosis is a group of pediatric neurodegenerative diseases. One of their causative genes, CLN10/CtsD, encodes cathepsin D, a major lysosomal protease. Central nervous system (CNS)-specific CtsD-deficient mice exhibit a neurodegenerative disease phenotype with accumulation of ceroid lipofuscins, granular osmiophilic deposits, and SQSTM1/p62. We focused on activated astrocytes and microglia in this neurodegenerative mouse brain, since there are few studies on the relationship between these accumulators and lysosomes in these glial cells. Activated microglia and astrocytes in this mouse thalamus at p24 were increased by approximately 2.5- and 4.6-fold compared with the control, while neurons were decreased by approximately half. Granular osmiophilic deposits were detected in microglial cell bodies and extended their processes in the thalamus. LAMP1-positive lysosomes, but not SQSTM1/p62 aggregates, accumulated in microglia of this mouse thalamus, whereas both lysosomes and SQSTM1/p62 aggregates accumulated in its astrocytes. TUNEL-positive signals were observed mainly in microglia, but few were observed in neurons and astrocytes. These signals were fragmented DNA from degenerated neurons engulfed by microglia or in the lysosomes of microglia. Abnormal autophagic vacuoles also accumulated in the lysosomes of microglia. Granular osmiophilic deposit-like structures localized to LAMP1-positive lysosomes in CtsD-deficient astrocytes. SQSTM1/p62-positive but LAMP1-negative membranous structures also accumulated in the astrocytes and were less condensed than typical granular osmiophilic deposits. These results suggest that CtsD deficiency leads to intracellular abnormalities in activated microglia and astrocytes in addition to neuronal degeneration.
    Keywords:  astrocyte; cathepsin D; correlative light and electron microscopy; microglia; neurodegeneration; neuronal ceroid lipofuscinosis
    DOI:  https://doi.org/10.1002/glia.24449
  57. Cancers (Basel). 2023 Jul 29. pii: 3866. [Epub ahead of print]15(15):
    The Multikinase Inhibitor AD80 Induces Mitotic Catastrophe and Autophagy in Pancreatic Cancer Cells.
    Keli Lima, Lívia Bassani Lins de Miranda, Anali Del Milagro Bernabe Garnique, Bruna Oliveira de Almeida, Mariane Cristina do Nascimento, Guilherme Augusto Sousa Alcântara, Glaucia Maria Machado-Santelli, Eduardo Magalhães Rego, João Agostinho Machado-Neto.
      Significant advances in understanding the molecular complexity of the development and progression of pancreatic cancer have been made, but this disease is still considered one of the most lethal human cancers and needs new therapeutic options. In the present study, the antineoplastic effects of AD80, a multikinase inhibitor, were investigated in models of pancreatic cancer. AD80 reduced cell viability and clonogenicity and induced polyploidy in pancreatic cancer cells. At the molecular level, AD80 reduced RPS6 and histone H3 phosphorylation and induced γH2AX and PARP1 cleavage. Additionally, the drug markedly decreased AURKA phosphorylation and expression. In PANC-1 cells, AD80 strongly induced autophagic flux (consumption of LC3B and SQSTM1/p62). AD80 modulated 32 out of 84 autophagy-related genes and was associated with vacuole organization, macroautophagy, response to starvation, cellular response to nitrogen levels, and cellular response to extracellular stimulus. In 3D pancreatic cancer models, AD80 also effectively reduced growth independent of anchorage and cell viability. In summary, AD80 induces mitotic aberrations, DNA damage, autophagy, and apoptosis in pancreatic cancer cells. Our exploratory study establishes novel targets underlying the antineoplastic activity of the drug and provides insights into the development of therapeutic strategies for this disease.
    Keywords:  AD80; aurora kinases; autophagy; multikinase inhibitor; pancreatic cancer
    DOI:  https://doi.org/10.3390/cancers15153866
  58. PLoS Genet. 2023 Aug 09. 19(8): e1010869
    Rege-1 promotes C. elegans survival by modulating IIS and TOR pathways.
    Yi-Ting Tsai, Chen-Hsi Chang, Hsin-Yue Tsai.
      Metabolic pathways are known to sense the environmental stimuli and result in physiological adjustments. The responding processes need to be tightly controlled. Here, we show that upon encountering P. aeruginosa, C. elegans upregulate the transcription factor ets-4, but this upregulation is attenuated by the ribonuclease, rege-1. As such, mutants with defective REGE-1 ribonuclease activity undergo ets-4-dependent early death upon challenge with P. aeruginosa. Furthermore, mRNA-seq analysis revealed associated global changes in two key metabolic pathways, the IIS (insulin/IGF signaling) and TOR (target of rapamycin) kinase signaling pathways. In particular, failure to degrade ets-4 mRNA in activity-defective rege-1 mutants resulted in upregulation of class II longevity genes, which are suppressed during longevity, and activation of TORC1 kinase signaling pathway. Genetic inhibition of either pathway way was sufficient to abolish the poor survival phenotype in rege-1 worms. Further analysis of ETS-4 ChIP data from ENCODE and characterization of one upregulated Class II gene, ins-7, support that the Class II genes are activated by ETS-4. Interestingly, deleting an upregulated Class II gene, acox-1.5, a peroxisome β-oxidation enzyme, largely rescues the fat lost phenotype and survival difference between rege-1 mutants and wild-types. Thus, rege-1 appears to be crucial for animal survival due to its tight regulation of physiological responses to environmental stimuli. This function is reminiscent of its mammalian ortholog, Regnase-1, which modulates the intestinal mTORC1 signaling pathway.
    DOI:  https://doi.org/10.1371/journal.pgen.1010869
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