bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2024‒06‒30
sixty-one papers selected by
Viktor Korolchuk, Newcastle University
  1. Developing a Tanshinone IIA Memetic by Targeting MIOS to Regulate mTORC1 and Autophagy in Glioblastoma.
  2. The Cytoprotective and Cytotoxic Functions of Autophagy in Response to mTOR Inhibitors.
  3. Defective mitochondria-lysosomal axis enhances the release of extracellular vesicles containing mitochondrial DNA and proteins in Huntington's disease.
  4. Control of mitophagy initiation and progression by the TBK1 adaptors NAP1 and SINTBAD.
  5. Modeling mTORopathy-related epilepsy in cultured murine hippocampal neurons using the multi-electrode array.
  6. Excessive STAU1 condensate drives mTOR translation and autophagy dysfunction in neurodegeneration.
  7. SKArred 2 death: neuroinflammatory breakdown of the hippocampus.
  8. Reduced Retinal Pigment Epithelial Autophagy Due to Loss of Rab12 Prenylation in a Human iPSC-RPE Model of Choroideremia.
  9. The role of autophagy in Parkinson's disease: a gender difference overview.
  10. (S)-ML-SA1 ACTIVATES AUTOPHAGY VIA TRPML1-TFEB PATHWAY.
  11. Aging and Autophagy: Roles in Musculoskeletal System Injury.
  12. Cardiac-Specific Suppression of Valosin-Containing Protein Induces Progressive Heart Failure and Premature Mortality Correlating with Temporal Dysregulations in mTOR Complex 2 and Protein Phosphatase 1.
  13. Last but not least: emerging roles of the autophagy-related protein ATG4D.
  14. The Cysteine Protease CfAtg4 Interacts with CfAtg8 to Govern the Growth, Autophagy and Pathogenicity of Colletotrichum fructicola.
  15. The role of LncRNA-mediated autophagy in cancer progression.
  16. The Effect of Tryptophan-to-Tyrosine Mutation at Position 61 of the Nonstructural Protein of Severe Fever with Thrombocytopenia Syndrome Virus on Viral Replication through Autophagosome Modulation.
  17. ATF4 and mTOR regulate metabolic reprogramming in TGF-β-treated lung fibroblasts.
  18. To eat or not to eat: a critical review on the role of autophagy in prostate carcinogenesis and prostate cancer therapeutics.
  19. Herpes Simplex Virus type 1 inhibits autophagy in glial cells but requires ATG5 for the success of viral replication.
  20. ISKNV Triggers AMPK/mTOR-Mediated Autophagy Signaling through Oxidative Stress, Inducing Antioxidant Enzyme Expression and Enhancing Viral Replication in GF-1 Cells.
  21. Lack of T04C9.1, the Homologue of Mammalian APPL2, Leads to Premature Ageing and Shortens Lifespan in Caenorhabditis elegans.
  22. CCT and Cullin1 Regulate the TORC1 Pathway to Promote Dendritic Arborization in Health and Disease.
  23. PDCD4 as a marker of mTOR pathway activation and therapeutic target in mycobacterial infections.
  24. DDHD2 promotes lipid droplet catabolism by acting as a TAG lipase and a cargo receptor for lipophagy.
  25. Autophagy in chronic rhinosinusitis with or without nasal polyps.
  26. Extracellular NCOA4 is a mediator of septic death by activating the AGER-NFKB pathway.
  27. Mitochondrial DNA Instability Supersedes Parkin Mutations in Driving Mitochondrial Proteomic Alterations and Functional Deficits in Polg Mutator Mice.
  28. Plekhm2 acts as an autophagy modulator in murine heart and cardiofibroblasts.
  29. Fluorescent hyaluronic acid nanoprodrug: A tumor-activated autophagy inhibitor for synergistic cancer therapy.
  30. Molecular mechanisms and physiological functions of autophagy.
  31. Critical roles of lncRNA-mediated autophagy in urologic malignancies.
  32. HIV-1 Tat-Mediated Human Müller Glial Cell Senescence Involves Endoplasmic Reticulum Stress and Dysregulated Autophagy.
  33. Research progress on the role of mitochondria in the process of hepatic ischemia-reperfusion injury.
  34. CMKLR1 senses chemerin/resolvin E1 to control adipose thermogenesis and modulate metabolic homeostasis.
  35. Blockage of Akt activation suppresses cadmium-induced renal tubular cellular damages through aggrephagy in HK-2 cells.
  36. Lysosome-Disrupting Agents in Combination with Venetoclax Increase Apoptotic Response in Primary Chronic Lymphocytic Leukemia (CLL) Cells Mediated by Lysosomal Cathepsin D Release and Inhibition of Autophagy.
  37. Biomolecular condensates as drivers of membrane trafficking and remodelling.
  38. TAT-beclin1 treatment accelerates the development of atherosclerotic lesions in ApoE-deficient mice.
  39. Neddylation activated TRIM25 desensitizes triple-negative breast cancer to paclitaxel via TFEB-mediated autophagy.
  40. PRRSV GP5 inhibits the antivirus effects of chaperone-mediated autophagy by targeting LAMP2A.
  41. Targeting the TRIM14/USP14 Axis Enhances Immunotherapy Efficacy by Inducing Autophagic Degradation of PD-L1.
  42. Interplay between mTOR and Purine Metabolism Enzymes and Its Relevant Role in Cancer.
  43. OTUD7B knockdown inhibits proliferation and autophagy through AKT/mTOR signaling pathway in human prostate cancer cell.
  44. A novel marine-derived mitophagy inducer ameliorates mitochondrial dysfunction and thermal hypersensitivity in paclitaxel-induced peripheral neuropathy.
  45. ADT-OH exhibits anti-metastatic activity on triple-negative breast cancer by combinatorial targeting of autophagy and mitochondrial fission.
  46. Incomplete autophagy and increased cholesterol synthesis during neuronal cell death caused by a synthetic cannabinoid, CP-55,940.
  47. PGAM5 interacts with and maintains BNIP3 to license cancer-associated muscle wasting.
  48. MiR-223 enhances lipophagy by suppressing CTSB in microglia following lysolecithin-induced demyelination in mice.
  49. Pathological Functions of Lysosomal Ion Channels in the Central Nervous System.
  50. WWP2 deletion aggravates acute kidney injury by targeting CDC20/autophagy axis.
  51. Loss of neuronal lysosomal acid lipase drives amyloid pathology in Alzheimer's disease.
  52. Targeting DRP1 with Mdivi-1 to correct mitochondrial abnormalities in ADOA plus syndrome.
  53. In Vivo Proximity Labeling Identifies a New Function for the Lifespan and Autophagy-regulating Kinase Pef1, an Ortholog of Human Cdk5.
  54. (-)-epigallocatechin 3-gallate protects pancreatic β-cell against excessive autophagy-induced injury through promoting FTO degradation.
  55. Early Postnatal Exposure to Midazolam Causes Lasting Histological and Neurobehavioral Deficits via Activation of the mTOR Pathway.
  56. Liver Cell Mitophagy in Metabolic Dysfunction-Associated Steatotic Liver Disease and Liver Fibrosis.
  57. The Anthraquinone Derivative C2 Enhances Oxaliplatin-Induced Cell Death and Triggers Autophagy via the PI3K/AKT/mTOR Pathway.
  58. Stat3-mediated Atg7 expression enhances anti-tumor immunity in melanoma.
  59. Cytoprotective Role of Autophagy in CDIP1 Expression-Induced Apoptosis in MCF-7 Breast Cancer Cells.
  60. Autophagic signaling promotes systems-wide remodeling in skeletal muscle upon oncometabolic stress by D2-HG.
  61. Exercise, mTOR Activation, and Potential Impacts on the Liver in Rodents.
  1. Int J Mol Sci. 2024 Jun 14. pii: 6586. [Epub ahead of print]25(12):
    Developing a Tanshinone IIA Memetic by Targeting MIOS to Regulate mTORC1 and Autophagy in Glioblastoma.
    Sonia Shinhmar, Judith Schaf, Katie Lloyd Jones, Olivier E Pardo, Philip Beesley, Robin S B Williams.
      Tanshinone IIA (T2A) is a bioactive compound that provides promise in the treatment of glioblastoma multiforme (GBM), with a range of molecular mechanisms including the inhibition of the mechanistic target of rapamycin complex 1 (mTORC1) and the induction of autophagy. Recently, T2A has been demonstrated to function through sestrin 2 (SESN) to inhibit mTORC1 activity, but its possible impact on autophagy through this pathway has not been investigated. Here, the model system Dictyostelium discoideum and GBM cell lines were employed to investigate the cellular role of T2A in regulating SESN to inhibit mTORC1 and activate autophagy through a GATOR2 component MIOS. In D. discoideum, T2A treatment induced autophagy and inhibited mTORC1 activity, with both effects lost upon the ablation of SESN (sesn-) or MIOS (mios-). We further investigated the targeting of MIOS to reproduce this effect of T2A, where computational analysis identified 25 novel compounds predicted to strongly bind the human MIOS protein, with one compound (MIOS inhibitor 3; Mi3) reducing cell proliferation in two GBM cells. Furthermore, Mi3 specificity was demonstrated through the loss of potency in the D. discoideum mios- cells regarding cell proliferation and the induction of autophagy. In GBM cells, Mi3 treatment also reduced mTORC1 activity and induced autophagy. Thus, a potential T2A mimetic showing the inhibition of mTORC1 and induction of autophagy in GBM cells was identified.
    Keywords:  Dictyostelium discoideum; GATOR2; MIOS; autophagy; cancer; drug discovery; glioblastoma; mTORC1; sestrin; tanshinone IIA
    DOI:  https://doi.org/10.3390/ijms25126586
  2. Front Biosci (Landmark Ed). 2024 Jun 24. 29(6): 231
    The Cytoprotective and Cytotoxic Functions of Autophagy in Response to mTOR Inhibitors.
    Ahmed M Elshazly, Aya A Elzahed, David A Gewirtz.
      The inhibitors of mammalian target of rapapmycin (mTOR), everolimus, temsirolimus and rapamycin, have a wide range of clinical utility; however, as is inevitably the case with other chemotherapeutic agents, resistance development constrains their effectiveness. One putative mechanism of resistance is the promotion of autophagy, which is a direct consequence of the inhibition of the mTOR signaling pathway. Autophagy is primarily considered to be a cytoprotective survival mechanism, whereby cytoplasmic components are recycled to generate energy and metabolic intermediates. The autophagy induced by everolimus and temsirolimus appears to play a largely protective function, whereas a cytotoxic function appears to predominate in the case of rapamycin. In this review we provide an overview of the autophagy induced in response to mTOR inhibitors in different tumor models in an effort to determine whether autophagy targeting could be of clinical utility as adjuvant therapy in association with mTOR inhibition.
    Keywords:  autophagy; cytoprotective; cytotoxic; everolimus; mTOR; rapamycin; temsirolimus
    DOI:  https://doi.org/10.31083/j.fbl2906231
  3. J Extracell Biol. 2022 Oct;1(10): e65
    Defective mitochondria-lysosomal axis enhances the release of extracellular vesicles containing mitochondrial DNA and proteins in Huntington's disease.
    Margarida Beatriz, Rita Vilaça, Sandra I Anjo, Bruno Manadas, Cristina Januário, A Cristina Rego, Carla Lopes.
      Mitochondrial and autophagy dysfunction are mechanisms proposed to be involved in the pathogenesis of several neurodegenerative diseases. Huntington's disease (HD) is a progressive neurodegenerative disorder associated with mutant Huntingtin-induced abnormalities in neuronal mitochondrial dynamics and quality control. Former studies suggest that the removal of defective mitochondria may be compromised in HD. Mitochondrial quality control (MQC) is a complex, well-orchestrated pathway that can be compromised through mitophagy dysregulation or impairment in the mitochondria-lysosomal axis. Another mitochondrial stress response is the generation of mitochondrial-derived vesicles that fuse with the endolysosomal system and form multivesicular bodies that are extruded from cells as extracellular vesicles (EVs). In this work, we aimed to study the presence of mitochondrial components in human EVs and the relation to the dysfunction of both mitochondria and the autophagy pathway. We comprehensively characterized the mitochondrial and autophagy alterations in premanifest and manifest HD carriers and performed a proteomic and genomic EVs profile. We observed that manifest HD patients exhibit mitochondrial and autophagy impairment associated with enhanced EVs release. Furthermore, we detected mitochondrial DNA and proteins in EVs released by HD cells and in neuronal-derived EVs including VDAC-1 and alpha and beta subunits of ATP synthase F1. HD-extracellular vesicles transport higher levels of mitochondrial genetic material in manifest HD patients, suggesting an alternative pathway for the secretion of reactive mitochondrial components. This study provides a novel framework connecting EVs enhanced release of mitochondrial components to mitochondrial and lysosomal dysfunction in HD.
    Keywords:  Huntington's disease; autophagy; extracellular vesicles; mitochondrial DNA; mitochondrial dysfunction; neuronal‐derived extracellular vesicles
    DOI:  https://doi.org/10.1002/jex2.65
  4. Nat Struct Mol Biol. 2024 Jun 25.
    Control of mitophagy initiation and progression by the TBK1 adaptors NAP1 and SINTBAD.
    Elias Adriaenssens, Thanh Ngoc Nguyen, Justyna Sawa-Makarska, Grace Khuu, Martina Schuschnig, Stephen Shoebridge, Marvin Skulsuppaisarn, Emily Maria Watts, Kitti Dora Csalyi, Benjamin Scott Padman, Michael Lazarou, Sascha Martens.
      Mitophagy preserves overall mitochondrial fitness by selectively targeting damaged mitochondria for degradation. The regulatory mechanisms that prevent PTEN-induced putative kinase 1 (PINK1) and E3 ubiquitin ligase Parkin (PINK1/Parkin)-dependent mitophagy and other selective autophagy pathways from overreacting while ensuring swift progression once initiated are largely elusive. Here, we demonstrate how the TBK1 (TANK-binding kinase 1) adaptors NAP1 (NAK-associated protein 1) and SINTBAD (similar to NAP1 TBK1 adaptor) restrict the initiation of OPTN (optineurin)-driven mitophagy by competing with OPTN for TBK1. Conversely, they promote the progression of nuclear dot protein 52 (NDP52)-driven mitophagy by recruiting TBK1 to NDP52 and stabilizing its interaction with FIP200. Notably, OPTN emerges as the primary recruiter of TBK1 during mitophagy initiation, which in return boosts NDP52-mediated mitophagy. Our results thus define NAP1 and SINTBAD as cargo receptor rheostats, elevating the threshold for mitophagy initiation by OPTN while promoting the progression of the pathway once set in motion by supporting NDP52. These findings shed light on the cellular strategy to prevent pathway hyperactivity while still ensuring efficient progression.
    DOI:  https://doi.org/10.1038/s41594-024-01338-y
  5. Exp Neurol. 2024 Jun 22. pii: S0014-4886(24)00200-0. [Epub ahead of print] 114874
    Modeling mTORopathy-related epilepsy in cultured murine hippocampal neurons using the multi-electrode array.
    Anouk M Heuvelmans, Martina Proietti Onori, Monica Frega, Jeffrey D de Hoogen, Eveline Nel, Ype Elgersma, Geeske M van Woerden.
      The mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway is a ubiquitous cellular pathway. mTORopathies, a group of disorders characterized by hyperactivity of the mTORC1 pathway, illustrate the prominent role of the mTOR pathway in disease pathology, often profoundly affecting the central nervous system. One of the most debilitating symptoms of mTORopathies is drug-resistant epilepsy, emphasizing the urgent need for a deeper understanding of disease mechanisms to develop novel anti-epileptic drugs. In this study, we explored the multiwell Multi-electrode array (MEA) system as a tool to identify robust network activity parameters in an approach to model mTORopathy-related epilepsy in vitro. To this extent, we cultured mouse primary hippocampal neurons on the multiwell MEA to identify robust network activity phenotypes in mTORC1-hyperactive neuronal networks. mTOR-hyperactivity was induced either through deletion of Tsc1 or overexpression of a constitutively active RHEB variant identified in patients, RHEBp.P37L. mTORC1 dependency of the phenotypes was assessed using rapamycin, and vigabatrin was applied to treat epilepsy-like phenotypes. We show that hyperactivity of the mTORC1 pathway leads to aberrant network activity. In both the Tsc1-KO and RHEB-p.P37L models, we identified changes in network synchronicity, rhythmicity, and burst characteristics. The presence of these phenotypes is prevented upon early treatment with the mTORC1-inhibitor rapamycin. Application of rapamycin in mature neuronal cultures could only partially rescue the network activity phenotypes. Additionally, treatment with the anti-epileptic drug vigabatrin reduced network activity and restored burst characteristics. Taken together, we showed that mTORC1-hyperactive neuronal cultures on the multiwell MEA system present reliable network activity phenotypes that can be used as an assay to explore the potency of new drug treatments targeting epilepsy in mTORopathy patients and may give more insights into the pathophysiological mechanisms underlying epilepsy in these patients.
    Keywords:  Epilepsy; Multi-electrode array; Network activity; Primary hippocampal neurons; Rapamycin; Vigabatrin; mTORopathy
    DOI:  https://doi.org/10.1016/j.expneurol.2024.114874
  6. J Cell Biol. 2024 Aug 05. pii: e202311127. [Epub ahead of print]223(8):
    Excessive STAU1 condensate drives mTOR translation and autophagy dysfunction in neurodegeneration.
    Ruiqian Zhao, Shijing Huang, Jingyu Li, Aihong Gu, Minjie Fu, Wei Hua, Ying Mao, Qun-Ying Lei, Boxun Lu, Wenyu Wen.
      The double-stranded RNA-binding protein Staufen1 (STAU1) regulates a variety of physiological and pathological events via mediating RNA metabolism. STAU1 overabundance was observed in tissues from mouse models and fibroblasts from patients with neurodegenerative diseases, accompanied by enhanced mTOR signaling and impaired autophagic flux, while the underlying mechanism remains elusive. Here, we find that endogenous STAU1 forms dynamic cytoplasmic condensate in normal and tumor cell lines, as well as in mouse Huntington's disease knockin striatal cells. STAU1 condensate recruits target mRNA MTOR at its 5'UTR and promotes its translation both in vitro and in vivo, and thus enhanced formation of STAU1 condensate leads to mTOR hyperactivation and autophagy-lysosome dysfunction. Interference of STAU1 condensate normalizes mTOR levels, ameliorates autophagy-lysosome function, and reduces aggregation of pathological proteins in cellular models of neurodegenerative diseases. These findings highlight the importance of balanced phase separation in physiological processes, suggesting that modulating STAU1 condensate may be a strategy to mitigate the progression of neurodegenerative diseases with STAU1 overabundance.
    DOI:  https://doi.org/10.1083/jcb.202311127
  7. Autophagy. 2024 Jun 27.
    SKArred 2 death: neuroinflammatory breakdown of the hippocampus.
    Thomas Bajaj, Tim Ebert, Larissa J Dillmann, Clara Sokn, Nils C Gassen, Jakob Hartmann.
      A multitude of cellular responses to intrinsic and extrinsic signals converge on macroautophagy/autophagy, a conserved catabolic process that degrades cytoplasmic constituents and organelles in the lysosome, particularly during starvation or stress. In addition to protein degradation, autophagy is deeply interconnected with unconventional protein secretion and polarized sorting at multiple levels within eukaryotic cells. Secretory autophagy (SA) has been recognized as a novel mechanism in which autophagosomes fuse with the plasma membrane and actively participate in the secretion of a series of cytosolic proteins, ranging from tissue remodeling factors to inflammatory molecules of the IL1 family. SA is partially controlled by the glucocorticoid-responsive, HSP90 co-chaperone FKBP5 and members of the SNARE proteins, SEC22B, SNAP23, SNAP29, STX3 and STX4. SA deregulation is implicated in several inflammatory pathologies, including cancer, cell death and degeneration. However, the key molecular mechanisms governing SA and its regulation remain elusive, as does its role in neuroinflammation and neurodegeneration. To further characterize SA and pinpoint its involvement in neuroinflammatory processes, we studied SA-relevant protein interaction networks in mouse brain, microglia and human postmortem brain tissue from control subjects and Alzheimer disease cases. We demonstrate that SA regulates neuroinflammation-mediated neurodegeneration via SKA2 and FKBP5 signaling.
    Keywords:  Alzheimer’s disease; FKBP5; SKA2; hippocampus; neuroinflammation; secretory autophagy
    DOI:  https://doi.org/10.1080/15548627.2024.2373675
  8. Cells. 2024 Jun 19. pii: 1068. [Epub ahead of print]13(12):
    Reduced Retinal Pigment Epithelial Autophagy Due to Loss of Rab12 Prenylation in a Human iPSC-RPE Model of Choroideremia.
    Maide Ö Raeker, Nirosha D Perera, Athanasios J Karoukis, Lisheng Chen, Kecia L Feathers, Robin R Ali, Debra A Thompson, Abigail T Fahim.
      Choroideremia is an X-linked chorioretinal dystrophy caused by mutations in CHM, encoding Rab escort protein 1 (REP-1), leading to under-prenylation of Rab GTPases (Rabs). Despite ubiquitous expression of CHM, the phenotype is limited to degeneration of the retina, retinal pigment epithelium (RPE), and choroid, with evidence for primary pathology in RPE cells. However, the spectrum of under-prenylated Rabs in RPE cells and how they contribute to RPE dysfunction remain unknown. A CRISPR/Cas-9-edited CHM-/- iPSC-RPE model was generated with isogenic control cells. Unprenylated Rabs were biotinylated in vitro and identified by tandem mass tag (TMT) spectrometry. Rab12 was one of the least prenylated and has an established role in suppressing mTORC1 signaling and promoting autophagy. CHM-/- iPSC-RPE cells demonstrated increased mTORC1 signaling and reduced autophagic flux, consistent with Rab12 dysfunction. Autophagic flux was rescued in CHM-/- cells by transduction with gene replacement (ShH10-CMV-CHM) and was reduced in control cells by siRNA knockdown of Rab12. This study supports Rab12 under-prenylation as an important cause of RPE cell dysfunction in choroideremia and highlights increased mTORC1 and reduced autophagy as potential disease pathways for further investigation.
    Keywords:  autophagy; choroideremia; disease modeling; human pluripotent stem cells; inherited retinal disease; retinal degeneration; retinal pigment epithelium
    DOI:  https://doi.org/10.3390/cells13121068
  9. Front Pharmacol. 2024 ;15 1408152
    The role of autophagy in Parkinson's disease: a gender difference overview.
    Laura Cucinotta, Deborah Mannino, Alessia Filippone, Adele Romano, Emanuela Esposito, Irene Paterniti.
      Recent studies have demonstrated dysregulation of the autophagy pathway in patients with Parkinson's disease (PD) and in animal models of PD, highlighting its emerging role in disease. In particular, several studies indicate that autophagy, which is an essential degradative process for the damaged protein homeostasis and the management of cell balance, can manifest significant variations according to gender. While some evidence suggests increased autophagic activation in men with PD, women may have distinct regulatory patterns. In this review, we examined the existing literature on gender differences in PD-associated autophagic processes, focusing on the autophagy related proteins (ATGs) and leucine rich repeat kinase 2 (LRRK2) genes. Also, this review would suggest that an in-depth understanding of these gender differences in autophagic processes could open new perspectives for personalized therapeutic strategies, promoting more effective and targeted management of PD.
    Keywords:  ATG (autophagy-related) proteins; Parkinson’s disease; autophagy; gender differences; leucin rich repeat kinase 2 (LRRK2)
    DOI:  https://doi.org/10.3389/fphar.2024.1408152
  10. Chembiochem. 2024 Jun 25. e202400506
    (S)-ML-SA1 ACTIVATES AUTOPHAGY VIA TRPML1-TFEB PATHWAY.
    Micael Rodrigues Cunha, Bruno S do Amaral, Jéssica E Takarada, Gabriel V Valderrama, Andrea N L Batista, João M Batista, Quezia B Cass, Rafael M Couñago, Katlin B Massirer.
      Autophagic flux plays a crucial role in various diseases. Recently, the lysosomal ion channel TRPML1 has emerged as a promising target in lysosomal storage diseases, such as mucolipidosis. The discovery of mucolipin synthetic agonist-1 (ML-SA1) has expanded our understanding of TRPML1's function and its potential therapeutic uses. However, ML-SA1 is a racemate with limited cellular potency and poor water solubility. In this study, we synthetized rac-ML-SA1, separated the enantiomers by chiral liquid chromatography and determined their absolute configuration by vibrational circular dichroism (VCD). In addition, we focused on investigating the impact of each enantiomer of ML-SA1 on the TRPML1-TFEB axis. Our findings revealed that (S)-ML-SA1 acts as an agonist for TRPML1 at the lysosomal membrane. This activation prompts transcription factor EB (TFEB) to translocate from the cytosol to the nucleus in a dose-dependent manner within live cells. Consequently, this signaling pathway enhances the expression of coordinated lysosomal expression and regulation (CLEAR) genes and activates autophagic flux. Our study presents evidence for the potential use of (S)-ML-SA1 in the development of new therapies for lysosomal storage diseases that target TRPML1.
    Keywords:  membrane protein genetically encoded calcium indicators (GECI) transient receptor potential (TRP) channels calcium channel lysosome
    DOI:  https://doi.org/10.1002/cbic.202400506
  11. Aging Dis. 2024 Jun 07.
    Aging and Autophagy: Roles in Musculoskeletal System Injury.
    Haifeng Zhang, Wenhui Gu, Genbin Wu, Yinxian Yu.
      Aging is a multifactorial process that ultimately leads to a decline in physiological function and a consequent reduction in the health span, and quality of life in elderly population. In musculoskeletal diseases, aging is often associated with a gradual loss of skeletal muscle mass and strength, resulting in reduced functional capacity and an increased risk of chronic metabolic diseases, leading to impaired function and increased mortality. Autophagy is a highly conserved physiological process by which cells, under the regulation of autophagy-related genes, degrade their own organelles and large molecules by lysosomal degradation. This process is unique to eukaryotic cells and is a strict regulator of homeostasis, the maintenance of energy and substance balance. Autophagy plays an important role in a wide range of physiological and pathological processes such as cell homeostasis, aging, immunity, tumorigenesis and neurodegenerative diseases. On the one hand, under mild stress conditions, autophagy mediates the restoration of homeostasis and proliferation, reduction of the rate of aging and delay of the aging process. On the other hand, under more intense stress conditions, an inadequate suppression of autophagy can lead to cellular aging. Conversely, autophagy activity decreases during aging. Due to the interrelationship between aging and autophagy, limited literature exists on this topic. Therefore, the objective of this review is to summarize the current concepts on aging and autophagy in the musculoskeletal system. The aim is to better understand the mechanisms of age-related changes in bone, joint and muscle, as well as the interaction relationship between autophagy and aging. Its goal is to provide a comprehensive perspective for the improvement of diseases of the musculoskeletal system.
    DOI:  https://doi.org/10.14336/AD.2024.0362
  12. Int J Mol Sci. 2024 Jun 11. pii: 6445. [Epub ahead of print]25(12):
    Cardiac-Specific Suppression of Valosin-Containing Protein Induces Progressive Heart Failure and Premature Mortality Correlating with Temporal Dysregulations in mTOR Complex 2 and Protein Phosphatase 1.
    Xiaonan Sun, Xicong Tang, Hongyu Qiu.
      Valosin-containing protein (VCP), an ATPase-associated protein, is emerging as a crucial regulator in cardiac pathologies. However, the pivotal role of VCP in the heart under physiological conditions remains undetermined. In this study, we tested a hypothesis that sufficient VCP expression is required for cardiac development and physiological cardiac function. Thus, we generated a cardiac-specific VCP knockout (KO) mouse model and assessed the consequences of VCP suppression on the heart through physiological and molecular studies at baseline. Our results reveal that homozygous KO mice are embryonically lethal, whereas heterozygous KO mice with a reduction in VCP by ~40% in the heart are viable at birth but progressively develop heart failure and succumb to mortality at the age of 10 to 12 months. The suppression of VCP induced a selective activation of the mammalian target of rapamycin complex 1 (mTORC1) but not mTORC2 at the early age of 12 weeks. The prolonged suppression of VCP increased the expression (by ~2 folds) and nuclear translocation (by >4 folds) of protein phosphatase 1 (PP1), a key mediator of protein dephosphorylation, accompanied by a remarked reduction (~80%) in AKTSer473 phosphorylation in VCP KO mouse hearts at a later age but not the early stage. These temporal molecular alterations were highly associated with the progressive decline in cardiac function. Overall, our findings shed light on the essential role of VCP in the heart under physiological conditions, providing new insights into molecular mechanisms in the development of heart failure.
    Keywords:  heart failure; mTOR complex; protein phosphatase 1; valosin-containing protein
    DOI:  https://doi.org/10.3390/ijms25126445
  13. Autophagy. 2024 Jun 26.
    Last but not least: emerging roles of the autophagy-related protein ATG4D.
    Emily McMann, Sharon M Gorski.
      The evolutionarily conserved ATG4 cysteine proteases regulate macroautophagy/autophagy through the priming and deconjugation of the Atg8-family proteins. In mammals there are four ATG4 family members (ATG4A, ATG4B, ATG4C, ATG4D) but ATG4D has been relatively understudied. Heightened interest in ATG4D has been stimulated by recent links to human disease. Notably, genetic variations in human ATG4D were implicated in a heritable neurodevelopmental disorder. Genetic analyses in dogs, along with loss-of-function zebrafish and mouse models, further support a neuroprotective role for ATG4D. Here we discuss the evidence connecting ATG4D to neurological diseases and other pathologies and summarize its roles in both autophagy-dependent and autophagy-independent cellular processes.
    Keywords:  Atg8; GABARAPL1; cancer; mitochondria; neurodegeneration; neurodevelopmental disorders
    DOI:  https://doi.org/10.1080/15548627.2024.2369436
  14. J Fungi (Basel). 2024 Jun 18. pii: 431. [Epub ahead of print]10(6):
    The Cysteine Protease CfAtg4 Interacts with CfAtg8 to Govern the Growth, Autophagy and Pathogenicity of Colletotrichum fructicola.
    Shufeng Guo, Shengpei Zhang.
      Camellia oleifera is a native woody oil plant in southern China and is infected with anthracnose wherever it is grown. We previously identified Colletotrichum fructicola as the major causal agent of anthracnose on C. oleifera and found that CfAtg8 regulates the pathogenicity and development of C. fructicola. Here, we revealed that CfAtg4 interacts with CfAtg8, contributing to the formation of autophagosomes. The CfAtg81-160 allele, which only contains 1-160 amino acids of the CfAtg8, partially recovered the autophagosome numbers and autophagy defects of the ΔCfatg4 mutant. Consequently, these recoveries resulted in the restoration of the defects of the ΔCfatg4 mutant in growth and responses to different external stresses, albeit to an extent. Importantly, we illustrated the critical roles of CfAtg81-160 in appressoria formation, and pathogenicity. Collectively, our findings provide new insights into the importance of the interaction between CfAtg8 and CfAtg4 in the growth, autophagy and pathogenicity of the phytopathogenic fungi.
    Keywords:  C. fructicola; CfAtg4; autophagy; cleavage; pathogenicity
    DOI:  https://doi.org/10.3390/jof10060431
  15. Front Cell Dev Biol. 2024 ;12 1348894
    The role of LncRNA-mediated autophagy in cancer progression.
    Zi-Yuan Liu, Jia-Ming Tang, Meng-Qi Yang, Zhi-Hui Yang, Jia-Zeng Xia.
      Long non-coding RNAs (lncRNAs) are a sort of transcripts that are more than 200 nucleotides in length. In recent years, many studies have revealed the modulatory role of lncRNAs in cancer. Typically, lncRNAs are linked to a variety of essential events, such as apoptosis, cellular proliferation, and the invasion of malignant cells. Simultaneously, autophagy, an essential intracellular degradation mechanism in eukaryotic cells, is activated to respond to multiple stressful circumstances, for example, nutrient scarcity, accumulation of abnormal proteins, and organelle damage. Autophagy plays both suppressive and promoting roles in cancer. Increasingly, studies have unveiled how dysregulated lncRNAs expression can disrupt autophagic balance, thereby contributing to cancer progression. Consequently, exploring the interplay between lncRNAs and autophagy holds promising implications for clinical research. In this manuscript, we methodically compiled the advances in the molecular mechanisms of lncRNAs and autophagy and briefly summarized the implications of the lncRNA-mediated autophagy axis.
    Keywords:  autophagy; cancer; chemoresistance; lncRNA; tumor progression
    DOI:  https://doi.org/10.3389/fcell.2024.1348894
  16. Int J Mol Sci. 2024 Jun 10. pii: 6394. [Epub ahead of print]25(12):
    The Effect of Tryptophan-to-Tyrosine Mutation at Position 61 of the Nonstructural Protein of Severe Fever with Thrombocytopenia Syndrome Virus on Viral Replication through Autophagosome Modulation.
    Ji-Young Park, Amal Senevirathne, Khristine Kaith S Lloren, John Hwa Lee.
      In our prior investigations, we elucidated the role of the tryptophan-to-tyrosine substitution at the 61st position in the nonstructural protein NSsW61Y in diminishing the interaction between nonstructural proteins (NSs) and nucleoprotein (NP), impeding viral replication. In this study, we focused on the involvement of NSs in replication via the modulation of autophagosomes. Initially, we examined the impact of NP expression levels, a marker for replication, upon the infection of HeLa cells with severe fever thrombocytopenia syndrome virus (SFTSV), with or without the inhibition of NP binding. Western blot analysis revealed a reduction in NP levels in NSsW61Y-expressing conditions. Furthermore, the expression levels of the canonical autophagosome markers p62 and LC3 decreased in HeLa cells expressing NSsW61Y, revealing the involvement of individual viral proteins on autophagy. Subsequent experiments confirmed that NSsW61Y perturbs autophagy flux, as evidenced by reduced levels of LC3B and p62 upon treatment with chloroquine, an inhibitor of autophagosome-lysosome fusion. LysoTracker staining demonstrated a decrease in lysosomes in cells expressing the NS mutant compared to those expressing wild-type NS. We further explored the mTOR-associated regulatory pathway, a key regulator affected by NS mutant expression. The observed inhibition of replication could be linked to conformational changes in the NSs, impairing their binding to NP and altering mTOR regulation, a crucial upstream signaling component in autophagy. These findings illuminate the intricate interplay between NSsW61Y and the suppression of host autophagy machinery, which is crucial for the generation of autophagosomes to facilitate viral replication.
    Keywords:  NP; NSs; SFTSV; autophagosome; replication
    DOI:  https://doi.org/10.3390/ijms25126394
  17. bioRxiv. 2024 Jun 13. pii: 2024.06.12.598694. [Epub ahead of print]
    ATF4 and mTOR regulate metabolic reprogramming in TGF-β-treated lung fibroblasts.
    Kun Woo D Shin, M Volkan Atalay, Rengul Cetin-Atalay, Erin M O'Leary, Mariel E Glass, Jennifer C Houpy Szafran, Parker S Woods, Angelo Y Meliton, Obada R Shamaa, Yufeng Tian, Gökhan M Mutlu, Robert B Hamanaka.
      Idiopathic pulmonary fibrosis is a fatal disease characterized by the TGF-β-dependent activation of lung fibroblasts, leading to excessive deposition of collagen proteins and progressive replacement of healthy lung with scar tissue. We and others have shown that fibroblast activation is supported by metabolic reprogramming, including the upregulation of the de novo synthesis of glycine, the most abundant amino acid found in collagen protein. How fibroblast metabolic reprogramming is regulated downstream of TGF-β is incompletely understood. We and others have shown that TGF-β-mediated activation of the Mechanistic Target of Rapamycin Complex 1 (mTORC1) and downstream upregulation of Activating Transcription Factor 4 (ATF4) promote increased expression of the enzymes required for de novo glycine synthesis; however, whether mTOR and ATF4 regulate other metabolic pathways in lung fibroblasts has not been explored. Here, we used RNA sequencing to determine how both ATF4 and mTOR regulate gene expression in human lung fibroblasts following TGF-β. We found that ATF4 primarily regulates enzymes and transporters involved in amino acid homeostasis as well as aminoacyl-tRNA synthetases. mTOR inhibition resulted not only in the loss of ATF4 target gene expression, but also in the reduced expression of glycolytic enzymes and mitochondrial electron transport chain subunits. Analysis of TGF-β-induced changes in cellular metabolite levels confirmed that ATF4 regulates amino acid homeostasis in lung fibroblasts while mTOR also regulates glycolytic and TCA cycle metabolites. We further analyzed publicly available single cell RNAseq data sets and found increased expression of ATF4 and mTOR metabolic targets in pathologic fibroblast populations from the lungs of IPF patients. Our results provide insight into the mechanisms of metabolic reprogramming in lung fibroblasts and highlight novel ATF4 and mTOR-dependent pathways that may be targeted to inhibit fibrotic processes.
    DOI:  https://doi.org/10.1101/2024.06.12.598694
  18. Front Pharmacol. 2024 ;15 1419806
    To eat or not to eat: a critical review on the role of autophagy in prostate carcinogenesis and prostate cancer therapeutics.
    Natalie Jayne Kurganovs, Nikolai Engedal.
      Around 1 in 7 men will be diagnosed with prostate cancer during their lifetime. Many strides have been made in the understanding and treatment of this malignancy over the years, however, despite this; treatment resistance and disease progression remain major clinical concerns. Recent evidence indicate that autophagy can affect cancer formation, progression, and therapeutic resistance. Autophagy is an evolutionarily conserved process that can remove unnecessary or dysfunctional components of the cell as a response to metabolic or environmental stress. Due to the emerging importance of autophagy in cancer, targeting autophagy should be considered as a potential option in disease management. In this review, along with exploring the advances made on understanding the role of autophagy in prostate carcinogenesis and therapeutics, we will critically consider the conflicting evidence observed in the literature and suggest how to obtain stronger experimental evidence, as the application of current findings in clinical practice is presently not viable.
    Keywords:  androgen deprivation; autophagy; cancer; carcinogenesis; chemotherapy; prostate; radiation; therapy
    DOI:  https://doi.org/10.3389/fphar.2024.1419806
  19. Front Microbiol. 2024 ;15 1411655
    Herpes Simplex Virus type 1 inhibits autophagy in glial cells but requires ATG5 for the success of viral replication.
    Inés Ripa, Sabina Andreu, Fernando Josa-Prado, Beatriz Fernández Gómez, Fernando de Castro, María Arribas, Raquel Bello-Morales, José Antonio López-Guerrero.
      Herpes Simplex Virus type 1 (HSV-1) 1 is a neurotropic virus that has been associated with neurodegenerative disorders. The dysregulation of autophagy by HSV-1 has been proposed as a potential cause of neurodegeneration. While studies have extensively tackled the interaction between autophagy and HSV-1 in neurons, research in glial cells is currently limited. Our studies demonstrate that HSV-1 inhibits, but not completely blocks, the formation of autophagosomes in human oligodendroglioma- and astrocytoma- derived cell lines. These findings have been confirmed in murine oligodendrocyte precursor cells (OPCs). Finally, this study investigates the impact of autophagy on HSV-1 infection in glial cells. While the lack of basal autophagy in LC3B knockout glial cells does not have a significant effect on viral infection, cells without the autophagy-related protein ATG5 exhibit reduced viral production. The absence of ATG5 leads to a decrease in the transcription and replication of viral genes, as well as a delay in the initial stages of the formation of HSV-1 replication compartments. These findings indicate that while autophagy may not play a significant role in antiviral defense in glial cells, HSV-1 may be inhibiting autophagy to exploit non-canonical functions of certain components of the autophagic machinery, such as ATG5, to benefit its lifecycle.
    Keywords:  ATG5; Herpes Simplex Virus type 1; autophagy; glial cells; multiple sclerosis; oligodendrocyte
    DOI:  https://doi.org/10.3389/fmicb.2024.1411655
  20. Viruses. 2024 Jun 04. pii: 914. [Epub ahead of print]16(6):
    ISKNV Triggers AMPK/mTOR-Mediated Autophagy Signaling through Oxidative Stress, Inducing Antioxidant Enzyme Expression and Enhancing Viral Replication in GF-1 Cells.
    Tsai-Ching Hsueh, Pin-Han Chen, Jiann-Ruey Hong.
      Infectious spleen and kidney necrosis virus (ISKNV) infections can induce the process of host cellular autophagy but have rarely been identified within the molecular autophagy signaling pathway. In the present study, we demonstrated that ISKNV induces ROS-mediated oxidative stress signals for the induction of 5'AMP-activated protein kinase/mechanistic target of rapamycin kinase (AMPK/mTOR)-mediated autophagy and upregulation of host antioxidant enzymes in fish GF-1 cells. We also examined ISKNV-induced oxidative stress, finding that reactive oxidative species (ROS) increased by 1.5-fold and 2.5-fold from day 2 to day 3, respectively, as assessed by the H2DCFDA assay for tracing hydrogen peroxide (H2O2), which was blocked by NAC treatment in fish GF-1 cells. Furthermore, ISKNV infection was shown to trigger oxidative stress/Nrf2 signaling from day 1 to day 3; this event was then correlated with the upregulation of antioxidant enzymes such as Cu/ZnSOD and MnSOD and was blocked by the antioxidant NAC. Using an MDC assay, TEM analysis and autophagy marker LC3-II/I ratio, we found that ROS stress can regulate autophagosome formation within the induction of autophagy, which was inhibited by NAC treatment in GF-1 cells. Through signal analysis, we found that AMPK/mTOR flux was modulated through inhibition of mTOR and activation of AMPK, indicating phosphorylation levels of mTOR Ser 2448 and AMPK Thr 172 from day 1 to day 3; however, this process was reversed by NAC treatment, which also caused a reduction in virus titer (TCID50%) of up to 1000 times by day 3 in GF-1 cells. Thus, ISKNV-induced oxidative stress signaling is blocked by antioxidant NAC, which can also either suppress mTOR/AMPK autophagic signals or reduce viral replication. These findings may provide the basis for the creation of DNA control and treatment strategies.
    Keywords:  DNA virus; ISKNV; ROS; antioxidant NAC; autophagy; fish; mTOR; oxidative stress
    DOI:  https://doi.org/10.3390/v16060914
  21. Genes (Basel). 2024 May 22. pii: 659. [Epub ahead of print]15(6):
    Lack of T04C9.1, the Homologue of Mammalian APPL2, Leads to Premature Ageing and Shortens Lifespan in Caenorhabditis elegans.
    Zirui Li, Zhiqiang Chen, Lianghao Zhao, Jiaqi Sun, Lin Yin, Yuwei Jiang, Xiaotong Shi, Ziye Song, Lu Zhang.
      Ageing has been identified as an independent risk factor for various diseases; however, the physiological basis and molecular changes related to ageing are still largely unknown. Here, we show that the level of APPL2, an adaptor protein, is significantly reduced in the major organs of aged mice. Knocking down APPL2 causes premature ageing of human umbilical vein endothelial cells (HUVECs). We find that a lack of T04C9.1, the homologue of mammalian APPL2, leads to premature ageing, slow movements, lipid deposition, decreased resistance to stresses, and shortened lifespan in Caenorhabditis elegans (C. elegans), which are associated with decreased autophagy. Activating autophagy by rapamycin or inhibition of let-363 suppresses the age-related alternations, impaired motility, and shortened lifespan of C. elegans, which are reversed by knocking down autophagy-related genes. Our work provides evidence that APPL2 and its C. elegans homologue T04C9.1 decrease with age and reveals that a lack of T04C9.1 bridges autophagy decline and ageing in C. elegans.
    Keywords:  APPL2; C. elegans; T04C9.1; ageing; autophagy; lifespan
    DOI:  https://doi.org/10.3390/genes15060659
  22. Cells. 2024 Jun 13. pii: 1029. [Epub ahead of print]13(12):
    CCT and Cullin1 Regulate the TORC1 Pathway to Promote Dendritic Arborization in Health and Disease.
    Erin N Lottes, Feyza Ciger, Shatabdi Bhattacharjee, Emily A Timmins, Benoit Tete, Tommy Tran, Jais Matta, Atit A Patel, Daniel N Cox.
      The development of cell-type-specific dendritic arbors is integral to the proper functioning of neurons within their circuit networks. In this study, we examine the regulatory relationship between the cytosolic chaperonin CCT, key insulin pathway genes, and an E3 ubiquitin ligase (Cullin1) in dendritic development. CCT loss of function (LOF) results in dendritic hypotrophy in Drosophila Class IV (CIV) multi-dendritic larval sensory neurons, and CCT has recently been shown to fold components of the TOR (Target of Rapamycin) complex 1 (TORC1) in vitro. Through targeted genetic manipulations, we confirm that an LOF of CCT and the TORC1 pathway reduces dendritic complexity, while overexpression of key TORC1 pathway genes increases the dendritic complexity in CIV neurons. Furthermore, both CCT and TORC1 LOF significantly reduce microtubule (MT) stability. CCT has been previously implicated in regulating proteinopathic aggregation, thus, we examine CIV dendritic development in disease conditions as well. The expression of mutant Huntingtin leads to dendritic hypotrophy in a repeat-length-dependent manner, which can be rescued by Cullin1 LOF. Together, our data suggest that Cullin1 and CCT influence dendritic arborization through the regulation of TORC1 in both health and disease.
    Keywords:  Drosophila; E3 ubiquitin ligase; Huntingtin; TORC1; chaperone; dendrite development
    DOI:  https://doi.org/10.3390/cells13121029
  23. Microbiol Spectr. 2024 Jun 24. e0006224
    PDCD4 as a marker of mTOR pathway activation and therapeutic target in mycobacterial infections.
    Ruchi Paroha, Jia Wang, Sunhee Lee.
      Programmed cell death protein 4 (PDCD4) is instrumental in regulating a range of cellular processes such as translation, apoptosis, signal transduction, and inflammatory responses. There is a notable inverse correlation between PDCD4 and the mammalian target of rapamycin (mTOR) pathway, which is integral to cellular growth control. Activation of mTOR is associated with the degradation of PDCD4. Although the role of PDCD4 is well established in oncogenesis and immune response regulation, its function in mycobacterial infections and its interplay with the mTOR pathway necessitate further elucidation. This study investigates the modulation of PDCD4 expression in the context of mycobacterial infections, revealing a consistent pattern of downregulation across diverse mycobacterial species. This observation underscores the potential utility of PDCD4 as a biomarker for assessing mTOR pathway activation during such infections. Building on this finding, we employed a novel approach using PDCD4-based mTOR (Tor)-signal-indicator (TOSI) reporter cells for the high-throughput screening of FDA-approved drugs, focusing on mTOR inhibitors. This methodology facilitated the identification of several agents, inclusive of known mTOR inhibitors, which upregulated PDCD4 expression and concurrently exhibited efficacy in impeding mycobacterial proliferation within macrophages. These results not only reinforce the significance of PDCD4 as a pivotal marker in the understanding of infectious diseases, particularly mycobacterial infections, but also illuminate its potential in the identification of mTOR inhibitors, thereby contributing to the advancement of therapeutic strategies.IMPORTANCE: This study emphasizes the critical role of the mammalian target of rapamycin (mTOR) pathway in macrophage responses to mycobacterial infections, elucidating how mycobacteria activate mTOR, resulting in PDCD4 degradation. The utilization of the (Tor)-signal-indicator (TOSI) vector for real-time monitoring of mTOR activity represents a significant advancement in understanding mTOR regulation during mycobacterial infection. These findings deepen our comprehension of mycobacteria's innate immune mechanisms and introduce PDCD4 as a novel marker for mTOR activity in infectious diseases. Importantly, this research laid the groundwork for high-throughput screening of mTOR inhibitors using FDA-approved drugs, offering the potential for repurposing treatments against mycobacterial infections. The identification of drugs that inhibit mTOR activation opens new avenues for host-directed therapies, marking a significant step forward in combating tuberculosis and other mycobacterial diseases.
    Keywords:  FDA-approved drug library and drug screening; PDCD4; mTOR; mycobacteria
    DOI:  https://doi.org/10.1128/spectrum.00062-24
  24. Autophagy. 2024 Jun 23. 1-3
    DDHD2 promotes lipid droplet catabolism by acting as a TAG lipase and a cargo receptor for lipophagy.
    Kun Gao, Fei Jia, Yao Li, Chenji Wang.
      Mutations in the DDHD2 (DDHD domain containing 2) gene cause autosomal recessive spastic paraplegia type 54 (SPG54), a rare neurodegenerative disorder characterized by the early childhood onset of progressive spastic paraplegia. DDHD2 is reported as the principal brain triacylglycerol (TAG) lipase whose dysfunction causes massive lipid droplet (LD) accumulation in the brains of SPG54 patients. However, the precise functions of DDHD2 in regulating LD catabolism are not yet fully understood. In a recent study, we demonstrate that DDHD2 interacts with multiple members of the Atg8-family proteins (MAP1LC3/LC3s, GABARAPs), which play crucial roles in lipophagy. DDHD2 possesses two LC3-interacting region (LIR) motifs that contribute to its LD-eliminating activity. Moreover, DDHD2 enhances the colocalization between LC3B and LDs to promote lipophagy. LD·ATTEC, a compound that tethers LC3 to LDs to enhance their macroautophagic/autophagic clearance, effectively counteracts DDHD2 deficiency-induced LD accumulation. These findings provide insights into the dual functions of DDHD2 as a TAG lipase and cargo receptor for lipophagy in neuronal LD catabolism, and also suggest a potential therapeutic approach for treating SPG54 patients.
    Keywords:  Atg8; LD·ATTEC; hereditary spastic paraplegia; lipid droplets; lipophagy; neurodegenerative disorders
    DOI:  https://doi.org/10.1080/15548627.2024.2356487
  25. Front Cell Dev Biol. 2024 ;12 1417735
    Autophagy in chronic rhinosinusitis with or without nasal polyps.
    Jing Pei, Zhaoran Ding, Cheng Jiao, Ying Tao, Huifen Yang, Jing Li.
      Basic research on chronic rhinosinusitis (CRS) has advanced significantly in the past two decades, yet a comprehensive understanding of its pathogenic mechanisms remains elusive. Concurrently, there is a growing interest among scientists in exploring the involvement of autophagy in various human diseases, including tumors and inflammatory conditions. While the role of autophagy in asthma has been extensively studied in airway inflammatory diseases, its significance in CRS with or without nasal polyps (NPs), a condition closely linked to asthma pathophysiology, has also garnered attention, albeit with conflicting findings across studies. This review delves into the role of autophagy in CRS, suggesting that modulating autophagy to regulate inflammatory responses could potentially serve as a novel therapeutic target.
    Keywords:  CRSsNP; CRSwNP; autophagy; chronic rhinosinusitis; nasal polyps
    DOI:  https://doi.org/10.3389/fcell.2024.1417735
  26. Autophagy. 2024 Jun 25.
    Extracellular NCOA4 is a mediator of septic death by activating the AGER-NFKB pathway.
    Jiao Liu, Yichun Wang, Ling Zeng, Chunhua Yu, Rui Kang, Daniel J Klionsky, Jianxin Jiang, Daolin Tang.
      Sepsis, a life-threatening condition resulting from a dysregulated response to pathogen infection, poses a significant challenge in clinical management. Here, we report a novel role for the autophagy receptor NCOA4 in the pathogenesis of sepsis. Activated macrophages and monocytes secrete NCOA4, which acts as a mediator of septic death in mice. Mechanistically, lipopolysaccharide, a major component of the outer membrane of Gram-negative bacteria, induces NCOA4 secretion through autophagy-dependent lysosomal exocytosis mediated by ATG5 and MCOLN1. Moreover, bacterial infection with E. coli or S. enterica leads to passive release of NCOA4 during GSDMD-mediated pyroptosis. Upon release, extracellular NCOA4 triggers the activation of the proinflammatory transcription factor NFKB/NF-κB by promoting the degradation of NFKBIA/IκB molecules. This process is dependent on the pattern recognition receptor AGER, rather than TLR4. In vivo studies employing endotoxemia and polymicrobial sepsis mouse models reveal that a monoclonal neutralizing antibody targeting NCOA4 or AGER delays animal death, protects against organ damage, and attenuates systemic inflammation. Furthermore, elevated plasma NCOA4 levels in septic patients, particularly in non-survivors, correlate positively with the sequential organ failure assessment score and concentrations of lactate and proinflammatory mediators, such as TNF, IL1B, IL6, and HMGB1. These findings demonstrate a previously unrecognized role of extracellular NCOA4 in inflammation, suggesting it as a potential therapeutic target for severe infectious diseases.
    Keywords:  Autophagy receptor; inflammation; lysosomal exocytosis; pattern recognition receptor; sepsis
    DOI:  https://doi.org/10.1080/15548627.2024.2372215
  27. Int J Mol Sci. 2024 Jun 11. pii: 6441. [Epub ahead of print]25(12):
    Mitochondrial DNA Instability Supersedes Parkin Mutations in Driving Mitochondrial Proteomic Alterations and Functional Deficits in Polg Mutator Mice.
    Andrew J Trease, Steven Totusek, Eliezer Z Lichter, Kelly L Stauch, Howard S Fox.
      Mitochondrial quality control is essential in mitochondrial function. To examine the importance of Parkin-dependent mechanisms in mitochondrial quality control, we assessed the impact of modulating Parkin on proteome flux and mitochondrial function in a context of reduced mtDNA fidelity. To accomplish this, we crossed either the Parkin knockout mouse or ParkinW402A knock-in mouse lines to the Polg mitochondrial mutator line to generate homozygous double mutants. In vivo longitudinal isotopic metabolic labeling was followed by isolation of liver mitochondria and synaptic terminals from the brain, which are rich in mitochondria. Mass spectrometry and bioenergetics analysis were assessed. We demonstrate that slower mitochondrial protein turnover is associated with loss of mtDNA fidelity in liver mitochondria but not synaptic terminals, and bioenergetic function in both tissues is impaired. Pathway analysis revealed loss of mtDNA fidelity is associated with disturbances of key metabolic pathways, consistent with its association with metabolic disorders and neurodegeneration. Furthermore, we find that loss of Parkin leads to exacerbation of Polg-driven proteomic consequences, though it may be bioenergetically protective in tissues exhibiting rapid mitochondrial turnover. Finally, we provide evidence that, surprisingly, dis-autoinhibition of Parkin (ParkinW402A) functionally resembles Parkin knockout and fails to rescue deleterious Polg-driven effects. Our study accomplishes three main outcomes: (1) it supports recent studies suggesting that Parkin dependence is low in response to an increased mtDNA mutational load, (2) it provides evidence of a potential protective role of Parkin insufficiency, and (3) it draws into question the therapeutic attractiveness of enhancing Parkin function.
    Keywords:  Parkin; Parkinson’s disease; aging; metabolism; mitochondria; mitophagy
    DOI:  https://doi.org/10.3390/ijms25126441
  28. Sci Rep. 2024 Jun 28. 14(1): 14949
    Plekhm2 acts as an autophagy modulator in murine heart and cardiofibroblasts.
    Sharon Etzion, Raneen Hijaze, Liad Segal, Sofia Pilcha, Dana Masil, Or Levi, Sigal Elyagon, Aviva Levitas, Yoram Etzion, Ruti Parvari.
      Plekhm2 is a protein regulating endosomal trafficking and lysosomal distribution. We recently linked a recessive inherited mutation in PLEKHM2 to a familial form of dilated cardiomyopathy and left ventricular non-compaction. These patients' primary fibroblasts exhibited abnormal lysosomal distribution and autophagy impairment. We therefore hypothesized that loss of PLEKHM2 impairs cardiac function via autophagy derangement. Here, we characterized the roles of Plekhm2 in the heart using global Plekhm2 knockout (PLK2-KO) mice and cultured cardiac cells. Compared to littermate controls (WT), young PLK2-KO mice exhibited no difference in heart function or autophagy markers but demonstrated higher basal AKT phosphorylation. Older PLK2-KO mice had body and heart growth retardation and increased LC3II protein levels. PLK2-KO mice were more vulnerable to fasting and, interestingly, impaired autophagy was noted in vitro, in Plekhm2-deficient cardiofibroblasts but not in cardiomyocytes. PLK2-KO hearts appeared to be less sensitive to pathological hypertrophy induced by angiotensin-II compared to WT. Our findings suggest a role of Plekhm2 in murine cardiac autophagy. Plekhm2 deficiency impaired autophagy in cardiofibroblasts, but the autophagy in cardiomyocytes is not critically dependent on Plekhm2. The absence of Plekhm2 in mice appears to promote compensatory mechanism(s) enabling the heart to manage angiotensin-II-induced stress without detrimental consequences.
    DOI:  https://doi.org/10.1038/s41598-024-65670-5
  29. Int J Biol Macromol. 2024 Jun 21. pii: S0141-8130(24)04165-5. [Epub ahead of print]274(Pt 1): 133360
    Fluorescent hyaluronic acid nanoprodrug: A tumor-activated autophagy inhibitor for synergistic cancer therapy.
    Yundi Wu, Xudong Liu, Can Yao, Jianqiang Chen, Xilong Wu, Mingqiang Zhu.
      Autophagy is a process that eliminates damaged cells and malfunctioning organelles via lysosomes, which is closely linked to cancer. Primaquine (PQ) was reported to impede autophagy flow by preventing autophagosomes from fusing with lysosomes at the late stage of autophagy. It will lead to cellular metabolic collapse and programmed cell death. Excessive or extended autophagy enhances the efficacy of chemotherapeutic drugs in cancer prevention. The utilization of autophagy inhibition in conjunction with chemotherapy has become a prevalent and reliable approach for the safe and efficient treatment of cancer. In this work, an acid-sensitive nanoprodrug (O@PD) targeting CD44 receptors was produced using Schiff-base linkages or electrostatic interactions from oxidized hyaluronic acid (OHA), PQ, and doxorubicin (DOX). The CD44-targeting prodrug system in triple-negative breast cancer (TNBC) cells was designed to selectively release DOX and PQ into the acidic tumor microenvironment and cellular endosomes. DOX was employed to investigate the cellular uptake and ex-vivo drug distribution of O@PD nanoprodrugs. PQ-induced autophagy suppression combined with DOX has a synergistic fatal impact in TNBC. O@PD nanoprodrugs demonstrated robust anticancer efficacy as well as excellent biological safety, making them suitable for clinical use.
    Keywords:  Autophagy inhibition; Hyaluronic acid; Nanoprodrug; Targeted therapy; pH-responsive
    DOI:  https://doi.org/10.1016/j.ijbiomac.2024.133360
  30. J Mol Biol. 2024 Jun 26. pii: S0022-2836(24)00294-8. [Epub ahead of print] 168692
    Molecular mechanisms and physiological functions of autophagy.
    Florian Wilfling, Martin Graef.
      
    DOI:  https://doi.org/10.1016/j.jmb.2024.168692
  31. Front Pharmacol. 2024 ;15 1405199
    Critical roles of lncRNA-mediated autophagy in urologic malignancies.
    Lifeng Gan, Liying Zheng, Junrong Zou, Peiyue Luo, Tao Chen, Jun Zou, Wei Li, Qi Chen, Le Cheng, Fangtao Zhang, Biao Qian.
      Urologic oncology is a significant public health concern on a global scale. Recent research indicates that long chain non-coding RNAs (lncRNAs) and autophagy play crucial roles in various cancers, including urologic malignancies. This article provides a summary of the latest research findings, suggesting that lncRNA-mediated autophagy could either suppress or promote tumors in prostate, kidney, and bladder cancers. The intricate network involving different lncRNAs, target genes, and mediated signaling pathways plays a crucial role in urological malignancies by modulating the autophagic process. Dysregulated expression of lncRNAs can disrupt autophagy, leading to tumorigenesis, progression, and enhanced resistance to therapy. Consequently, targeting particular lncRNAs that control autophagy could serve as a dependable diagnostic tool and a promising prognostic biomarker in urologic oncology, while also holding potential as an effective therapeutic approach.
    Keywords:  autophagy; lncRNA; molecular mechanisms; pathways; urologic oncologies
    DOI:  https://doi.org/10.3389/fphar.2024.1405199
  32. Viruses. 2024 Jun 03. pii: 903. [Epub ahead of print]16(6):
    HIV-1 Tat-Mediated Human Müller Glial Cell Senescence Involves Endoplasmic Reticulum Stress and Dysregulated Autophagy.
    Uma Maheswari Deshetty, Nivedita Chatterjee, Shilpa Buch, Palsamy Periyasamy.
      Antiretroviral treatments have notably extended the lives of individuals with HIV and reduced the occurrence of comorbidities, including ocular manifestations. The involvement of endoplasmic reticulum (ER) stress in HIV-1 pathogenesis raises questions about its correlation with cellular senescence or its role in initiating senescent traits. This study investigated how ER stress and dysregulated autophagy impact cellular senescence triggered by HIV-1 Tat in the MIO-M1 cell line (human Müller glial cells). Cells exposed to HIV-1 Tat exhibited increased vimentin expression combined with markers of ER stress (BiP, p-eIF2α), autophagy (LC3, Beclin-1, p62), and the senescence marker p21 compared to control cells. Western blotting and staining techniques like SA-β-gal were employed to examine these markers. Additionally, treatments with ER stress inhibitor 4-PBA before HIV-1 Tat exposure led to a decreased expression of ER stress, senescence, and autophagy markers. Conversely, pre-treatment with the autophagy inhibitor 3-MA resulted in reduced autophagy and senescence markers but did not alter ER stress markers compared to control cells. The findings suggest a link between ER stress, dysregulated autophagy, and the initiation of a senescence phenotype in MIO-M1 cells induced by HIV-1 Tat exposure.
    Keywords:  ER stress; HIV-1 Tat; Müller glial cells; autophagy; senescence
    DOI:  https://doi.org/10.3390/v16060903
  33. Gastroenterol Rep (Oxf). 2024 ;12 goae066
    Research progress on the role of mitochondria in the process of hepatic ischemia-reperfusion injury.
    Yujie Zhou, Tao Qiu, Tianyu Wang, Bo Yu, Kang Xia, Jiayu Guo, Yiting Liu, Xiaoxiong Ma, Long Zhang, Jilin Zou, Zhongbao Chen, Jiangqiao Zhou.
      During liver ischemia-reperfusion injury, existing mechanisms involved oxidative stress, calcium overload, and the activation of inflammatory responses involve mitochondrial injury. Mitochondrial autophagy, a process that maintains the normal physiological activity of mitochondria, promotes cellular metabolism, improves cellular function, and facilitates organelle renewal. Mitochondrial autophagy is involved in oxidative stress and apoptosis, of which the PINK1-Parkin pathway is a major regulatory pathway, and the deletion of PINK1 and Parkin increases mitochondrial damage, reactive oxygen species production, and inflammatory response, playing an important role in mitochondrial quality regulation. In addition, proper mitochondrial permeability translational cycle regulation can help maintain mitochondrial stability and mitigate hepatocyte death during ischemia-reperfusion injury. This mechanism is also closely related to oxidative stress, calcium overload, and the aforementioned autophagy pathway, all of which leads to the augmentation of the mitochondrial membrane permeability transition pore opening and cause apoptosis. Moreover, the release of mitochondrial DNA (mtDNA) due to oxidative stress further aggravates mitochondrial function impairment. Mitochondrial fission and fusion are non-negligible processes required to maintain the dynamic renewal of mitochondria and are essential to the dynamic stability of these organelles. The Bcl-2 protein family also plays an important regulatory role in the mitochondrial apoptosis signaling pathway. A series of complex mechanisms work together to cause hepatic ischemia-reperfusion injury (HIRI). This article reviews the role of mitochondria in HIRI, hoping to provide new therapeutic clues for alleviating HIRI in clinical practice.
    Keywords:  Bcl-2; MPTP; autophagy; hepatic ischemia-reperfusion injury; mitochondria; reactive oxygen species
    DOI:  https://doi.org/10.1093/gastro/goae066
  34. Fundam Res. 2024 May;4(3): 575-588
    CMKLR1 senses chemerin/resolvin E1 to control adipose thermogenesis and modulate metabolic homeostasis.
    Zewei Zhao, Siqi Liu, Bingxiu Qian, Lin Zhou, Jianglin Shi, Junxi Liu, Lin Xu, Zhonghan Yang.
      Induction of beige fat for thermogenesis is a potential therapy to improve homeostasis against obesity. β3-adrenoceptor (β3-AR), a type of G protein-coupled receptor (GPCR), is believed to mediate the thermogenesis of brown fat in mice. However, β3-AR has low expression in human adipose tissue, precluding its activation as a standalone clinical modality. This study aimed at identifying a potential GPCR target to induce beige fat. We found that chemerin chemokine-like receptor 1 (CMKLR1), one of the novel GPCRs, mediated the development of beige fat via its two ligands, chemerin and resolvin E1 (RvE1). The RvE1 levels were decreased in the obese mice, and RvE1 treatment led to a substantial improvement in obese features and augmented beige fat markers. Inversely, despite sharing the same receptor as RvE1, the chemerin levels were increased in obesogenic conditions, and chemerin treatment led to an augmented obese phenotype and a decline of beige fat markers. Moreover, RvE1 and chemerin induced or restrained the development of beige fat, respectively, via the mechanistic target of rapamycin complex 1 (mTORC1) signaling pathway. We further showed that RvE1 and chemerin regulated mTORC1 signaling differentially by forming hydrogen bonds with different binding sites of CMKLR1. In conclusion, our study showed that RvE1 and chemerin affected metabolic homeostasis differentially, suggesting that selectively modulating CMKLR1 may be a potential therapeutic target for restoring metabolic homeostasis.
    Keywords:  CMKLR1; Chemerin; Insulin resistance; Obesity; Resolvin E1; Thermogenesis
    DOI:  https://doi.org/10.1016/j.fmre.2022.06.014
  35. Sci Rep. 2024 06 24. 14(1): 14552
    Blockage of Akt activation suppresses cadmium-induced renal tubular cellular damages through aggrephagy in HK-2 cells.
    Kota Fujiki, K Tanabe, S Suzuki, A Mochizuki, M Mochizuki-Kashio, T Sugaya, T Mizoguchi, M Itoh, A Nakamura-Ishizu, H Inamura, M Matsuoka.
      We have reported that an environmental pollutant, cadmium, promotes cell death in the human renal tubular cells (RTCs) through hyperactivation of a serine/threonine kinase Akt. However, the molecular mechanisms downstream of Akt in this process have not been elucidated. Cadmium has a potential to accumulate misfolded proteins, and proteotoxicity is involved in cadmium toxicity. To clear the roles of Akt in cadmium exposure-induced RTCs death, we investigated the possibility that Akt could regulate proteotoxicity through autophagy in cadmium chloride (CdCl2)-exposed HK-2 human renal proximal tubular cells. CdCl2 exposure promoted the accumulation of misfolded or damaged proteins, the formation of aggresomes (pericentriolar cytoplasmic inclusions), and aggrephagy (selective autophagy to degrade aggresome). Pharmacological inhibition of Akt using MK2206 or Akti-1/2 enhanced aggrephagy by promoting dephosphorylation and nuclear translocation of transcription factor EB (TFEB)/transcription factor E3 (TFE3), lysosomal transcription factors. TFEB or TFE3 knockdown by siRNAs attenuated the protective effects of MK2206 against cadmium toxicity. These results suggested that aberrant activation of Akt attenuates aggrephagy via TFEB or TFE3 to facilitate CdCl2-induced cell death. Furthermore, these roles of Akt/TFEB/TFE3 were conserved in CdCl2-exposed primary human RTCs. The present study shows the molecular mechanisms underlying Akt activation that promotes cadmium-induced RTCs death.
    Keywords:  Aggresome; Akt; Cadmium; Cell death; Renal proximal tubular cells
    DOI:  https://doi.org/10.1038/s41598-024-64579-3
  36. Cells. 2024 Jun 15. pii: 1041. [Epub ahead of print]13(12):
    Lysosome-Disrupting Agents in Combination with Venetoclax Increase Apoptotic Response in Primary Chronic Lymphocytic Leukemia (CLL) Cells Mediated by Lysosomal Cathepsin D Release and Inhibition of Autophagy.
    Madhumita S Manivannan, Xiaoyan Yang, Nirav Patel, Anthea Peters, James B Johnston, Spencer B Gibson.
      Venetoclax and obinutuzumab are becoming frontline therapies for chronic lymphocytic leukemia (CLL) patients. Unfortunately, drug resistance still occurs, and the combination could be immunosuppressive. Lysosomes have previously been identified as a target for obinutuzumab cytotoxicity in CLL cells, but the mechanism remains unclear. In addition, studies have shown that lysosomotropic agents can cause synergistic cell death in vitro when combined with the BTK inhibitor, ibrutinib, in primary CLL cells. This indicates that targeting lysosomes could be a treatment strategy for CLL. In this study, we have shown that obinutuzumab induces lysosome membrane permeabilization (LMP) and cathepsin D release in CLL cells. Inhibition of cathepsins reduced obinutuzumab-induced cell death in CLL cells. We further determined that the lysosomotropic agent siramesine in combination with venetoclax increased cell death in primary CLL cells through an increase in reactive oxygen species (ROS) and cathepsin release. Siramesine treatment also induced synergistic cytotoxicity when combined with venetoclax. Microenvironmental factors IL4 and CD40L or incubation with HS-5 stromal cells failed to significantly protect CLL cells from siramesine- and venetoclax-induced apoptosis. We also found that siramesine treatment inhibited autophagy through reduced autolysosomes. Finally, the autophagy inhibitor chloroquine failed to further increase siramesine-induced cell death. Taken together, lysosome-targeting drugs could be an effective strategy in combination with venetoclax to overcome drug resistance in CLL.
    Keywords:  CLL; autophagy; cathepsins; cell death; lysosomes
    DOI:  https://doi.org/10.3390/cells13121041
  37. Curr Opin Cell Biol. 2024 Jun 26. pii: S0955-0674(24)00072-3. [Epub ahead of print]89 102393
    Biomolecular condensates as drivers of membrane trafficking and remodelling.
    Rini Ravindran, Stephen W Michnick.
      Membrane remodelling is essential for the trafficking of macromolecules throughout the cell, a process that regulates various aspects of cellular health and pathology. Recent studies implicate the role of biomolecular condensates in regulating multiple steps of the membrane trafficking pathway including but not limited to the organization of the trafficking machinery, dynamic remodeling of membranes, spatial and functional regulation, and response to cellular signals. The implicated proteins contain key structural elements, most notably prion-like domains within intrinsically disordered regions that are necessary for biomolecular condensate formation at fusion sites in processes like endocytic assembly, autophagy, organelle biosynthesis and synaptic vesicle fusion. Experimental and theoretical advances in the field continue to demonstrate that protein condensates can perform mechanical work, the implications of which can be extrapolated to diverse areas of membrane biology.
    DOI:  https://doi.org/10.1016/j.ceb.2024.102393
  38. FASEB J. 2024 Jul 15. 38(13): e23765
    TAT-beclin1 treatment accelerates the development of atherosclerotic lesions in ApoE-deficient mice.
    Lianbo Liu, Qingjie Wang, Yawen Li, Jiali Cai, Yexing Wang, Yun Li, Ruxing Wang, Ling Sun, Xiaowei Zheng, Anwen Yin.
      The importance of autophagy in atherosclerosis has garnered significant attention regarding the potential applications of autophagy inducers. However, the impact of TAT-Beclin1, a peptide inducer of autophagy, on the development of atherosclerotic plaques remains unclear. Single-cell omics analysis indicates a notable reduction in GAPR1 levels within fibroblasts, stromal cells, and macrophages during atherosclerosis. Tat-beclin1 (T-B), an autophagy-inducing peptide derived from Beclin1, could selectively bind to GAPR1, relieving its inhibition on Beclin1 and thereby augmenting autophagosome formation. To investigate its impact on atherosclerosic plaque progression, we established the ApoE-/- mouse model of carotid atherosclerotic plaques. Surprisingly, intravenous administration of Tat-beclin1 dramatically accelerated the development of carotid artery plaques. Immunofluorescence analysis suggested that macrophage aggregation and autophagosome formation within atherosclerotic plaques were significantly increased upon T-B treatment. However, immunofluorescence and transmission electron microscopy (TEM) analysis revealed a reduction in autophagy flux through lysosomes. In vitro, the interaction between T-B and GAPR1 was confirmed in RAW264.7 cells, resulting in the increased accumulation of p62/SQSTM1 and LC3-II in the presence of ox-LDL. Additionally, T-B treatment elevated the protein levels of p62/SQSTM1, LC3-II, and cleaved caspase 1, along with the secretion of IL-1β in response to ox-LDL exposure. In summary, our study underscores that T-B treatment amplifies abnormal autophagy and inflammation, consequently exacerbating atherosclerotic plaque development in ApoE-/- mice.
    Keywords:  Tat‐beclin1; atherosclerosis; autophagy; macrophage
    DOI:  https://doi.org/10.1096/fj.202400161RR
  39. J Exp Clin Cancer Res. 2024 Jun 26. 43(1): 177
    Neddylation activated TRIM25 desensitizes triple-negative breast cancer to paclitaxel via TFEB-mediated autophagy.
    Bowen Zheng, Fengyuan Qian, Xuehui Wang, Yuying Wang, Baian Zhou, Lin Fang.
      BACKGROUND: Paclitaxel (PTX) treatment resistance is an important factor leading to poor prognosis in triple-negative breast cancer (TNBC), therefore there is an urgent need to identify new target for combination therapy. Neddylation is a post-translational process that introduces a ubiquitin-like protein called neural precursor cell expressed developmentally downregulated protein 8 (NEDD8). Previous studies have found that neddylation is activated in multiple tumors, but its relationship with PTX chemotherapy sensitivity has not been reported.METHODS: Differences in UBC12 and NEDD8 expression levels between PTX-sensitive and PTX-insensitive TNBC tissues were validated using public databases and immunohistochemistry. The in vitro and in vivo functional experiments were used to observe the effect of neddylation inhibition combined with PTX therapy on tumor progression. Co-IP, western blot and PCR assays were used to investigate the molecular mechanisms. Molecular docking was used to simulate the protein binding of UBC12 and TRIM25. Molecular dynamics simulation was used to observe the changes in TRIM25 protein conformation.
    RESULTS: We found that in TNBC that is insensitive to PTX, NEDD8 and NEDD8 conjugating enzyme UBC12 are highly expressed. Treatment with the NEDD8-activating enzyme (NAE) inhibitor mln4924 or knockdown of UBC12 significantly increased the sensitivity of the tumor to PTX, and this increase in sensitivity is related to UBC12-mediated autophagy activation. Mechanistically, UBC12 can transfer NEDD8 to E3 ubiquitin ligase tripartite motif containing 25 (TRIM25) at K117. Molecular dynamics simulations indicate that the neddylation modification of TRIM25 reduces steric hindrance in its RING domain, facilitating the binding of TRIM25 and ubiquitylated substrates. Subsequently, TRIM25 promotes the nuclear translocation of transcription factor EB (TFEB) and transcription of autophagy related genes by increasing K63-polyubiquitination of TFEB, thereby reducing tumor sensitivity to PTX.
    CONCLUSIONS: Neddylation is activated in PTX-insensitive TNBC. Specifically, autophagy gene transcriptional activation mediated by the UBC12/TRIM25/TFEB axis reduces TNBC sensitivity to PTX. Neddylation suppression combination with PTX treatment shows a synergistic anti-tumor effect.
    Keywords:  Autophagy; Neddylation; PTX resistance; TFEB; TRIM25
    DOI:  https://doi.org/10.1186/s13046-024-03085-w
  40. mBio. 2024 Jun 28. e0053224
    PRRSV GP5 inhibits the antivirus effects of chaperone-mediated autophagy by targeting LAMP2A.
    Wen Li, Mengting Zhang, Yueshuai Wang, Shijie Zhao, Pengli Xu, Zhiying Cui, Jing Chen, Pingan Xia, Yina Zhang.
      Autophagy is an important biological process in host defense against viral infection. However, many viruses have evolved various strategies to disrupt the host antiviral system. Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus with a large economic impact on the swine industry. At present, studies on the escape mechanism of PRRSV in the autophagy process, especially through chaperone-mediated autophagy (CMA), are limited. This study confirmed that PRRSV glycoprotein 5 (GP5) could disrupt the formation of the GFAP-LAMP2A complex by inhibiting the MTORC2/PHLPP1/GFAP pathway, promoting the dissociation of the pGFAP-EF1α complex, and blocking the K63-linked polyubiquitination of LAMP2A to inhibit the activity of CMA. Further research demonstrated that CMA plays an anti-PRRSV role by antagonizing nonstructural protein 11 (NSP11)-mediated inhibition of type I interferon (IFN-I) signaling. Taken together, these results indicate that PRRSV GP5 inhibits the antiviral effect of CMA by targeting LAMP2A. This research provides new insight into the escape mechanism of immunosuppressive viruses in CMA.IMPORTANCE: Viruses have evolved sophisticated mechanisms to manipulate autophagy to evade degradation and immune responses. Porcine reproductive and respiratory syndrome virus (PRRSV) is a typical immunosuppressive virus that causes enormous economic losses in the swine industry. However, the mechanism by which PRRSV manipulates autophagy to defend against host antiviral effects remains unclear. In this study, we found that PRRSV GP5 interacts with LAMP2A and disrupts the formation of the GFAP-LAMP2A complex, thus inhibiting the activity of CMA and subsequently enhancing the inhibitory effect of the NSP11-mediated IFN-I signaling pathway, ultimately facilitating PRRSV replication. Our study revealed a novel mechanism by which PRRSV escapes host antiviral effects through CMA, providing a potential host target, LAMP2A, for developing antiviral drugs and contributing to understanding the escape mechanism of immunosuppressive viruses.
    Keywords:  CMA; GFAP; GP5; LAMP2A; PRRSV
    DOI:  https://doi.org/10.1128/mbio.00532-24
  41. Cancer Res. 2024 Jun 26.
    Targeting the TRIM14/USP14 Axis Enhances Immunotherapy Efficacy by Inducing Autophagic Degradation of PD-L1.
    Di Liu, Mengqiu Li, Zhiyao Zhao, Liang Zhou, Feng Zhi, Zhiyong Guo, Jun Cui.
      Immunotherapy has greatly improved cancer treatment in recent years by harnessing the immune system to target cancer cells. The first immunotherapeutic agent approved by the US Food and Drug Administration (FDA) was interferon a (IFNa). Treatment with IFNa can lead to effective immune activation and attenuate tumor immune evasion, but persistent treatment has been shown to elicit immune suppressive effects. Here, we identified an autophagy-dependent mechanism by which IFNa triggers tumor immune evasion by upregulating PD-L1 to suppress the anti-tumor activity of CD8+ T cells. Mechanistically, IFNa increased transcription of TRIM14, which recruited the deubiquitinase USP14 to inhibit the autophagic degradation of PD-L1. USP14 removed K63-linked ubiquitin chains from PD-L1, impairing its recognition by the cargo receptor p62 (also known as SQSTM1) for subsequent autophagic degradation. Combining the USP14 inhibitor IU1 with IFNa and anti-CTLA4 treatment effectively suppressed tumor growth without significant toxicity. This work suggests a strategy for targeting selective autophagy to abolish PD-L1-mediated cancer immune evasion.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-23-3971
  42. Int J Mol Sci. 2024 Jun 19. pii: 6735. [Epub ahead of print]25(12):
    Interplay between mTOR and Purine Metabolism Enzymes and Its Relevant Role in Cancer.
    Simone Allegrini, Marcella Camici, Mercedes Garcia-Gil, Rossana Pesi, Maria Grazia Tozzi.
      Tumor cells reprogram their metabolism to meet the increased demand for nucleotides and other molecules necessary for growth and proliferation. In fact, cancer cells are characterized by an increased "de novo" synthesis of purine nucleotides. Therefore, it is not surprising that specific enzymes of purine metabolism are the targets of drugs as antineoplastic agents, and a better knowledge of the mechanisms underlying their regulation would be of great help in finding new therapeutic approaches. The mammalian target of the rapamycin (mTOR) signaling pathway, which is often activated in cancer cells, promotes anabolic processes and is a major regulator of cell growth and division. Among the numerous effects exerted by mTOR, noteworthy is its empowerment of the "de novo" synthesis of nucleotides, accomplished by supporting the formation of purinosomes, and by increasing the availability of necessary precursors, such as one-carbon formyl group, bicarbonate and 5-phosphoribosyl-1-pyrophosphate. In this review, we highlight the connection between purine and mitochondrial metabolism, and the bidirectional relation between mTOR signaling and purine synthesis pathways.
    Keywords:  AKT; c-Myc; cancer; cell survival; mTOR; mitochondria; one-carbon metabolism; proliferation; purine metabolism; purinosome
    DOI:  https://doi.org/10.3390/ijms25126735
  43. Discov Oncol. 2024 Jun 27. 15(1): 247
    OTUD7B knockdown inhibits proliferation and autophagy through AKT/mTOR signaling pathway in human prostate cancer cell.
    Yae Ji Kim, Hui Ju Lee, Kyung Hyun Kim, Sung Pil Cho, Ju Young Jung.
      Prostate cancer (PCa) is the second leading disease of cancer-related death in men around the world, and it is almost impossible to treat advanced PCa. OTUD7B is a member of the deubiquitinase family that undergoes a post-translational transformation process, which is essential for cell stability and signaling and is known to play a critical role in cancer. However, its role in PCa has not been discovered. The aim of the study was to investigate the expression and mechanism of OTUD7B in PCa cells. According to the database, high OTUD7B expression showed a poor prognosis. Therefore, we downregulated OTUD7B using siRNA and confirmed the role of OTUD7B in PC3 prostate cancer cells. OTUD7B knockdown effectively induced apoptosis and inhibited the proliferation in PC3 cells. OTUD7B knockdown inhibited autophagy through AKT/mTOR signaling. We also confirmed the relationship between AKT/mTOR signaling and autophagy through rapamycin, an mTOR inhibitor. Taken together, OTUD7B promotes the proliferation, and autophagy, and inhibits apoptosis of prostate cancer cells via the AKT/mTOR signaling pathway.
    Keywords:  Autophagy; OTUD7B; Proliferation; Prostate cancer; mTOR
    DOI:  https://doi.org/10.1007/s12672-024-01073-2
  44. Br J Pharmacol. 2024 Jun 26.
    A novel marine-derived mitophagy inducer ameliorates mitochondrial dysfunction and thermal hypersensitivity in paclitaxel-induced peripheral neuropathy.
    Sangwoo Im, Dae Jin Jeong, Eunmi Kim, Jae-Hyeong Choi, Hye-Ji Jang, Young Yeon Kim, Jee-Hyun Um, Jihoon Lee, Yeon-Ju Lee, Kang-Min Lee, Dabin Choi, Eunhee Yoo, Hyi-Seung Lee, Jeanho Yun.
      BACKGROUND AND PURPOSE: Mitochondrial dysfunction contributes to the pathogenesis and maintenance of chemotherapy-induced peripheral neuropathy (CIPN), a significant limitation of cancer chemotherapy. Recently, the stimulation of mitophagy, a pivotal process for mitochondrial homeostasis, has emerged as a promising treatment strategy for neurodegenerative diseases, but its therapeutic effect on CIPN has not been explored. Here, we assessed the mitophagy-inducing activity of 3,5-dibromo-2-(2',4'-dibromophenoxy)-phenol (PDE701), a diphenyl ether derivative isolated from the marine sponge Dysidea sp., and investigated its therapeutic effect on a CIPN model.EXPERIMENTAL APPROACH: Mitophagy activity was determined by a previously established mitophagy assay using mitochondrial Keima (mt-Keima). Mitophagy induction was further verified by western blotting, immunofluorescence, and electron microscopy. Mitochondrial dysfunction was analysed by measuring mitochondrial superoxide levels in SH-SY5Y cells and Drosophila larvae. A thermal nociception assay was used to evaluate the therapeutic effect of PDE701 on the paclitaxel-induced thermal hyperalgesia phenotype in Drosophila larvae.
    KEY RESULTS: PDE701 specifically induced mitophagy but was not toxic to mitochondria. PDE701 ameliorated paclitaxel-induced mitochondrial dysfunction in both SH-SY5Y cells and Drosophila larvae. Importantly, PDE701 also significantly ameliorated paclitaxel-induced thermal hyperalgesia in Drosophila larvae. Knockdown of ATG5 or ATG7 abolished the effect of PDE701 on thermal hyperalgesia, suggesting that PDE701 exerts its therapeutic effect through mitophagy induction.
    CONCLUSION AND IMPLICATIONS: This study identified PDE701 as a novel mitophagy inducer and a potential therapeutic compound for CIPN. Our results suggest that mitophagy stimulation is a promising strategy for the treatment of CIPN and that marine organisms are a potential source of mitophagy-inducing compounds.
    Keywords:  Dysidea sp; mitochondrial dysfunction; mitophagy; paclitaxel; peripheral neuropathy
    DOI:  https://doi.org/10.1111/bph.16476
  45. Cell Death Dis. 2024 Jun 28. 15(6): 463
    ADT-OH exhibits anti-metastatic activity on triple-negative breast cancer by combinatorial targeting of autophagy and mitochondrial fission.
    Shihui Yu, Zhiting Cao, Fangfang Cai, Yingying Yao, Xiaoyao Chang, Xiaoyang Wang, Hongqin Zhuang, Zi-Chun Hua.
      High basal autophagy and enhanced mitochondrial fission in triple-negative breast cancer (TNBC) cells support cell migration and promote plasticity of cancer cell metabolism. Here, we suggest a novel combination therapy approach for the treatment of TNBC that targets Drp1-mediated mitochondrial fission and autophagy pathways. Hydrogen sulfide (H2S) mediates a myriad of biological processes, including autophagy and mitochondrial function. In this study, we demonstrated that 5-(4-hydroxyphenyl)-3H-1,2-dithiole-3-thione (ADT-OH), one of the most widely utilized sustained-release H2S donors, effectively suppresses metastasis of TNBC cells in the absence of proliferation inhibition in vitro and in vivo. ADT-OH treatment ameliorated autophagy flux by suppressing autophagosome formation and induced mitochondrial elongation through decreasing expression of dynamin-related protein 1 (Drp1) and increasing expression of mitochondrial fusion protein (Mfn2). At the same time, ADT-OH downregulated mitophagy flux and inhibited mitochondrial function, eventually leading to the inhibition of migration and invasion in TNBC cells. In vivo, intraperitoneal administration of ADT-OH revealed a potent anti-metastatic activity in three different animal models, the MDA-MB-231 orthotopic xenograft model, the 4T1-Luci orthotopic model and the 4T1-Luci tail vein metastasis model. However, ADT-OH has an extremely low water solubility, which is a significant barrier to its effectiveness. Thus, we demonstrated that the solubility of ADT-OH in water can be improved significantly by absorption with hydroxypropyl-β-cyclodextrin (CD). Remarkably, the obtained CD-ADT-OH demonstrated superior anti-cancer effect to ADT-OH in vivo. Altogether, this study describes a novel regulator of mammalian mitochondrial fission and autophagy, with potential utility as an experimental therapeutic agent for metastatic TNBC.
    DOI:  https://doi.org/10.1038/s41419-024-06829-w
  46. Neurotoxicology. 2024 Jun 26. pii: S0161-813X(24)00068-8. [Epub ahead of print]
    Incomplete autophagy and increased cholesterol synthesis during neuronal cell death caused by a synthetic cannabinoid, CP-55,940.
    Hikari Tachibana, Moeka Nomura, Takeshi Funakoshi, Kana Unuma, Toshihiko Aki, Koichi Uemura.
      There is a propensity for synthetic cannabinoid abuse to spread worldwide. CP-55,940, a synthetic cannabinoid having the ability to activate both CB1 and CB2 receptors, has been shown to induce cell death in neurons as well as other cells. Here we investigate molecular events underling the adverse effects of CP-55,940 on neuronal cells. Exposure of mouse neuroblastoma Neuro2a cells to 10-50µM CP-55,940 results in concentration-dependent cell death that is not accompanied by an induction of apoptosis. CP-55,940 also stimulates autophagy, but the stimulation is not followed by an increase in autophagic degradation. Transcriptome analysis using DNA microarray revealed the increased expression of genes for the cholesterol biosynthesis pathway that is associated with the activation of SREBP-2, the master transcriptional regulator of cholesterol biosynthesis. However, free cholesterol is localized mainly to cytoplasmic structures, although it is localized to the plasma membrane in healthy cells. Thus, cellular trafficking of cholesterol seems to be somewhat disrupted in CP-55,940 stimulated cells. These results show for the first time that CP-55,940 stimulates autophagy as well as cholesterol biosynthesis, although not all the processes involved in the cellular response to CP-55,940 seem to be complete in these cells.
    Keywords:  CP-55,940; Nero2a; autophagy; cholesterol
    DOI:  https://doi.org/10.1016/j.neuro.2024.06.013
  47. Autophagy. 2024 Jun 26. 1-16
    PGAM5 interacts with and maintains BNIP3 to license cancer-associated muscle wasting.
    Qingyuan Zhang, Chunhui Chen, Ye Ma, Xinyi Yan, Nianhong Lai, Hao Wang, Baogui Gao, Anna Meilin Gu, Qinrui Han, Qingling Zhang, Lei La, Xuegang Sun.
      Regressing the accelerated degradation of skeletal muscle protein is a significant goal for cancer cachexia management. Here, we show that genetic deletion of Pgam5 ameliorates skeletal muscle atrophy in various tumor-bearing mice. pgam5 ablation represses excessive myoblast mitophagy and effectively suppresses mitochondria meltdown and muscle wastage. Next, we define BNIP3 as a mitophagy receptor constitutively associating with PGAM5. bnip3 deletion restricts body weight loss and enhances the gastrocnemius mass index in the age- and tumor size-matched experiments. The NH2-terminal region of PGAM5 binds to the PEST motif-containing region of BNIP3 to dampen the ubiquitination and degradation of BNIP3 to maintain continuous mitophagy. Finally, we identify S100A9 as a pro-cachectic chemokine via activating AGER/RAGE. AGER deficiency or S100A9 inhibition restrains skeletal muscle loss by weakening the interaction between PGAM5 and BNIP3. In conclusion, the AGER-PGAM5-BNIP3 axis is a novel but common pathway in cancer-associated muscle wasting that can be targetable. Abbreviation: AGER/RAGE: advanced glycation end-product specific receptor; BA1: bafilomycin A1; BNIP3: BCL2 interacting protein 3; BNIP3L: BCL2 interacting protein 3 like; Ckm-Cre: creatinine kinase, muscle-specific Cre; CM: conditioned medium; CON/CTRL: control; CRC: colorectal cancer; FUNDC1: FUN14 domain containing 1; MAP1LC3A/LC3A: microtubule associated protein 1 light chain 3 alpha; PGAM5: PGAM family member 5, mitochondrial serine/threonine protein phosphatase; S100A9: S100 calcium binding protein A9; SQSTM1/p62: sequestosome 1; TOMM20: translocase of outer mitochondrial membrane 20; TIMM23: translocase of inner mitochondrial membrane 23; TSKO: tissue-specific knockout; VDAC1: voltage dependent anion channel 1.
    Keywords:  AGER; S100A9; cachexia; cancer; mitophagy; muscle atrophy
    DOI:  https://doi.org/10.1080/15548627.2024.2360340
  48. Lipids Health Dis. 2024 Jun 22. 23(1): 194
    MiR-223 enhances lipophagy by suppressing CTSB in microglia following lysolecithin-induced demyelination in mice.
    Hao Ma, Zhi-Lin Ou, Nima Alaeiilkhchi, Yong-Quan Cheng, Kai Chen, Jia-Yu Chen, Ru-Qin Guo, Min-Yue He, Shi-Yi Tang, Xin Zhang, Zhi-Ping Huang, Junhao Liu, Jie Liu, Qing-An Zhu, Zu-Cheng Huang, Hui Jiang.
      BACKGROUND: Lipid droplet (LD)-laden microglia is a key pathological hallmark of multiple sclerosis. The recent discovery of this novel microglial subtype, lipid-droplet-accumulating microglia (LDAM), is notable for increased inflammatory factor secretion and diminished phagocytic capability. Lipophagy, the autophagy-mediated selective degradation of LDs, plays a critical role in this context. This study investigated the involvement of microRNAs (miRNAs) in lipophagy during demyelinating diseases, assessed their capacity to modulate LDAM subtypes, and elucidated the potential underlying mechanisms involved.METHODS: C57BL/6 mice were used for in vivo experiments. Two weeks post demyelination induction at cervical level 4 (C4), histological assessments and confocal imaging were performed to examine LD accumulation in microglia within the lesion site. Autophagic changes were observed using transmission electron microscopy. miRNA and mRNA multi-omics analyses identified differentially expressed miRNAs and mRNAs under demyelinating conditions and the related autophagy target genes. The role of miR-223 in lipophagy under these conditions was specifically explored. In vitro studies, including miR-223 upregulation in BV2 cells via lentiviral infection, validated the bioinformatics findings. Immunofluorescence staining was used to measure LD accumulation, autophagy levels, target gene expression, and inflammatory mediator levels to elucidate the mechanisms of action of miR-223 in LDAM.
    RESULTS: Oil Red O staining and confocal imaging revealed substantial LD accumulation in the demyelinated spinal cord. Transmission electron microscopy revealed increased numbers of autophagic vacuoles at the injury site. Multi-omics analysis revealed miR-223 as a crucial regulatory gene in lipophagy during demyelination. It was identified that cathepsin B (CTSB) targets miR-223 in autophagy to integrate miRNA, mRNA, and autophagy gene databases. In vitro, miR-223 upregulation suppressed CTSB expression in BV2 cells, augmented autophagy, alleviated LD accumulation, and decreased the expression of the inflammatory mediator IL-1β.
    CONCLUSION: These findings indicate that miR-223 plays a pivotal role in lipophagy under demyelinating conditions. By inhibiting CTSB, miR-223 promotes selective LD degradation, thereby reducing the lipid burden and inflammatory phenotype in LDAM. This study broadens the understanding of the molecular mechanisms of lipophagy and proposes lipophagy induction as a potential therapeutic approach to mitigate inflammatory responses in demyelinating diseases.
    Keywords:  CTSB (cathepsin B); Demyelination; Lipid droplets; Lipophagy; MiR-223; Microglia
    DOI:  https://doi.org/10.1186/s12944-024-02185-y
  49. Int J Mol Sci. 2024 Jun 14. pii: 6565. [Epub ahead of print]25(12):
    Pathological Functions of Lysosomal Ion Channels in the Central Nervous System.
    Jianke Cen, Nan Hu, Jiawen Shen, Yongjing Gao, Huanjun Lu.
      Lysosomes are highly dynamic organelles that maintain cellular homeostasis and regulate fundamental cellular processes by integrating multiple metabolic pathways. Lysosomal ion channels such as TRPML1-3, TPC1/2, ClC6/7, CLN7, and TMEM175 mediate the flux of Ca2+, Cl-, Na+, H+, and K+ across lysosomal membranes in response to osmotic stimulus, nutrient-dependent signals, and cellular stresses. These ion channels serve as the crucial transducers of cell signals and are essential for the regulation of lysosomal biogenesis, motility, membrane contact site formation, and lysosomal homeostasis. In terms of pathophysiology, genetic variations in these channel genes have been associated with the development of lysosomal storage diseases, neurodegenerative diseases, inflammation, and cancer. This review aims to discuss the current understanding of the role of these ion channels in the central nervous system and to assess their potential as drug targets.
    Keywords:  central nervous system; disease; immune inflammation; ion channel; lysosomes
    DOI:  https://doi.org/10.3390/ijms25126565
  50. J Adv Res. 2024 Jun 22. pii: S2090-1232(24)00252-2. [Epub ahead of print]
    WWP2 deletion aggravates acute kidney injury by targeting CDC20/autophagy axis.
    Ran You, Yanwei Li, Yuteng Jiang, Dandan Hu, Menglei Gu, Wei Zhou, Shengnan Zhang, Mi Bai, Yunwen Yang, Yue Zhang, Songming Huang, Zhanjun Jia, Aihua Zhang.
      INTRODUCTION: Acute kidney injury (AKI) is associated with high morbidity and mortality rates. The molecular mechanisms underlying AKI are currently being extensively investigated. WWP2 is an E3 ligase that regulates cell proliferation and differentiation. Whether WWP2 plays a regulatory role in AKI remains to be elucidated.OBJECTIVES: We aimed to investigate the implication of WWP2 in AKI and its underlying mechanism in the present study.
    METHODS: We utilized renal tissues from patients with AKI and established AKI models in global or tubule-specific knockout (cKO) mice strains to study WWP2's implication in AKI. We also systemically analyzed ubiquitylation omics and proteomics to decipher the underlying mechanism.
    RESULTS: In the present study, we found that WWP2 expression significantly increased in the tubules of kidneys with AKI. Global or tubule-specific knockout of WWP2 significantly aggravated renal dysfunction and tubular injury in AKI kidneys, whereas WWP2 overexpression significantly protected tubular epithelial cells against cisplatin. WWP2 deficiency profoundly affected autophagy in AKI kidneys. Further analysis with ubiquitylation omics, quantitative proteomics and experimental validation suggested that WWP2 mediated poly-ubiquitylation of CDC20, a negative regulator of autophagy. CDC20 was significantly decreased in AKI kidneys, and selective inhibiting CDC20 with apcin profoundly alleviated renal dysfunction and tubular injury in the cisplatin model with or without WWP2 cKO, indicating that CDC20 may serve as a downstream target of WWP2 in AKI. Inhibiting autophagy with 3-methyladenine blocked apcin's protection against cisplatin-induced renal tubular cell injury. Activating autophagy by rapamycin significantly protected against cisplatin-induced AKI in WWP2 cKO mice, whereas inhibiting autophagy by 3-methyladenine further aggravated apoptosis in cisplatin-exposed WWP2 KO cells.
    CONCLUSION: Taken together, our data indicated that the WWP2/CDC20/autophagy may be an essential intrinsic protective mechanism against AKI. Further activating WWP2 or inhibiting CDC20 may be novel therapeutic strategies for AKI.
    Keywords:  Acute kidney injury; Autophagy; CDC20; Tubular epithelial cells; WWP2
    DOI:  https://doi.org/10.1016/j.jare.2024.06.015
  51. bioRxiv. 2024 Jun 10. pii: 2024.06.09.596693. [Epub ahead of print]
    Loss of neuronal lysosomal acid lipase drives amyloid pathology in Alzheimer's disease.
    Alexandra M Barnett, Lamar Dawkins, Jian Zou, Elizabeth McNair, Viktoriya D Nikolova, Sheryl S Moy, Greg T Sutherland, Julia Stevens, Meagan Colie, Kemi Katemboh, Hope Kellner, Corina Damian, Sagan DeCastro, Ryan P Vetreno, Leon G Coleman.
      Underlying drivers of late-onset Alzheimer's disease (LOAD) pathology remain unknown. However, multiple biologically diverse risk factors share a common pathological progression. To identify convergent molecular abnormalities that drive LOAD pathogenesis we compared two common midlife risk factors for LOAD, heavy alcohol use and obesity. This revealed that disrupted lipophagy is an underlying cause of LOAD pathogenesis. Both exposures reduced lysosomal flux, with a loss of neuronal lysosomal acid lipase (LAL). This resulted in neuronal lysosomal lipid (NLL) accumulation, which opposed Aβ localization to lysosomes. Neuronal LAL loss both preceded (with aging) and promoted (targeted knockdown) Aβ pathology and cognitive deficits in AD mice. The addition of recombinant LAL ex vivo and neuronal LAL overexpression in vivo prevented amyloid increases and improved cognition. In WT mice, neuronal LAL declined with aging and correlated negatively with entorhinal Aβ. In healthy human brain, LAL also declined with age, suggesting this contributes to the age-related vulnerability for AD. In human LOAD LAL was further reduced, correlated negatively with Aβ 1-42 , and occurred with polymerase pausing at the LAL gene. Together, this finds that the loss of neuronal LAL promotes NLL accumulation to impede degradation of Aβ in neuronal lysosomes to drive AD amyloid pathology.Summary: Cellular and molecular drivers of late-onset Alzheimer's disease (LOAD) are unknown, though several risk factors account for the majority of disease incidence 1-5 . Though diverse in their biological natures, each of these risk exposures converge on a shared pathological progression with the accumulation of amyloid early in the disease. Human genetic and transcriptomic studies suggest a role for altered lipid metabolism 6-9 , though the mechanism has been unknown. Here, using two common midlife risk exposures for LOAD, we found that dysfunctional lipophagy caused by the loss of lysosomal acid lipase (LAL) promotes early LOAD pathogenesis. Both midlife obesity and heavy alcohol reduced neuronal LAL, causing an increase in neuronal lysosomal lipid, and a subsequent accumulation of Aβ in the extra-lysosomal cytosol. This loss of LAL preceded and promoted Aβ pathology and cognitive deficits in AD mice. The addition of recombinant LAL ex vivo and neuronal LAL overexpression in vivo prevented increases in amyloid and improved cognition. In human brain, LAL declined with age in healthy subjects, similar to rodents, showing robust losses in LOAD subjects with polymerase pausing. Together, this implicates neuronal LAL loss in LOAD pathogenesis and presents LAL as a promising diagnostic, preventative, and/or therapeutic target for AD.
    DOI:  https://doi.org/10.1101/2024.06.09.596693
  52. JCI Insight. 2024 Jun 25. pii: e180582. [Epub ahead of print]
    Targeting DRP1 with Mdivi-1 to correct mitochondrial abnormalities in ADOA plus syndrome.
    Yan Lin, Dongdong Wang, Busu Li, Jiayin Wang, Ling Xu, Xiaohan Sun, Kunqian Ji, Chuanzhu Yan, Fuchen Liu, Yuying Zhao.
      Autosomal dominant optic atrophy plus (ADOA+) is characterized by primary optic nerve atrophy accompanied by a spectrum of degenerative neurological symptoms. Despite ongoing research, no effective treatments are currently available for this condition. Our study provided evidence for the pathogenicity of an unreported c.1780T>C variant in the OPA1 gene through patient-derived skin fibroblasts and an engineered HEK293T cell line with OPA1 downregulation. We demonstrated that OPA1 insufficiency promoted mitochondrial fragmentation and increased DRP1 expression, disrupting mitochondrial dynamics. Consequently, this disruption enhanced mitophagy and caused mitochondrial dysfunction, contributing to the ADOA+ phenotype. Notably, the Drp1 inhibitor, mitochondrial division inhibitor-1 (Mdivi-1), effectively mitigated the adverse effects of OPA1 impairment. These effects included reduced Drp1 phosphorylation, decreased mitochondrial fragmentation, and balanced mitophagy. Thus, we propose that intervening in DRP1 with Mdivi-1 could correct mitochondrial abnormalities, offering a promising therapeutic approach for managing ADOA+.
    Keywords:  Autophagy; Drug therapy; Mitochondria; Neuroscience; Ophthalmology
    DOI:  https://doi.org/10.1172/jci.insight.180582
  53. bioRxiv. 2024 Jun 14. pii: 2024.06.12.598664. [Epub ahead of print]
    In Vivo Proximity Labeling Identifies a New Function for the Lifespan and Autophagy-regulating Kinase Pef1, an Ortholog of Human Cdk5.
    Haitao Zhang, Dongmei Zhang, Ling Li, Belinda Willard, Kurt W Runge.
      Cdk5 is a highly-conserved, noncanonical cell division kinase important to the terminal differentiation of mammalian cells in multiple organ systems. We previously identified Pef1, the Schizosaccharomyces pombe ortholog of cdk5, as regulator of chronological lifespan. To reveal the processes impacted by Pef1, we developed APEX2-biotin phenol-mediated proximity labeling in S. pombe. Efficient labeling required a short period of cell wall digestion and eliminating glucose and nitrogen sources from the medium. We identified 255 high-confidence Pef1 neighbors in growing cells and a novel Pef1-interacting partner, the DNA damage response protein Rad24. The Pef1-Rad24 interaction was validated by reciprocal proximity labeling and co-immunoprecipitation. Eliminating Pef1 partially rescued the DNA damage sensitivity of cells lacking Rad24. To monitor how Pef1 neighbors change under different conditions, cells induced for autophagy were labeled and 177 high-confidence Pef1 neighbors were identified. Gene ontology (GO) analysis of the Pef1 neighbors identified proteins participating in processes required for autophagosome expansion including regulation of actin dynamics and vesicle-mediated transport. Some of these proteins were identified in both exponentially growing and autophagic cells. Pef1-APEX2 proximity labeling therefore identified a new Pef1 function in modulating the DNA damage response and candidate processes that Pef1 and other cdk5 orthologs may regulate.
    DOI:  https://doi.org/10.1101/2024.06.12.598664
  54. Autophagy. 2024 Jun 24.
    (-)-epigallocatechin 3-gallate protects pancreatic β-cell against excessive autophagy-induced injury through promoting FTO degradation.
    Yixue Shao, Yuhan Zhang, Suyun Zou, Jianan Wang, Xirui Li, Miaozhen Qin, Liangjun Sun, Wenyue Yin, Xiaoai Chang, Shusen Wang, Xiao Han, Tijun Wu, Fang Chen.
      Excessive macroautophagy/autophagy leads to pancreatic β-cell failure that contributes to the development of diabetes. Our previous study proved that the occurrence of deleterious hyperactive autophagy attributes to glucolipotoxicity-induced NR3C1 activation. Here, we explored the potential protective effects of (-)-epigallocatechin 3-gallate (EGCG) on β-cell-specific NR3C1 overexpression mice in vivo and NR3C1-enhanced β cells in vitro. We showed that EGCG protects pancreatic β cells against NR3C1 enhancement-induced failure through inhibiting excessive autophagy. RNA demethylase FTO (FTO alpha-ketoglutarate dependent dioxygenase) caused diminished m6A modifications on mRNAs of three pro-oxidant genes (Tlr4, Rela, Src) and, hence, oxidative stress occurs; by contrast, EGCG promotes FTO degradation by the ubiquitin-proteasome system in NR3C1-enhanced β cells, which alleviates oxidative stress, and thereby prevents excessive autophagy. Moreover, FTO overexpression abolishes the beneficial effects of EGCG on β cells against NR3C1 enhancement-induced damage. Collectively, our results demonstrate that EGCG protects pancreatic β cells against NR3C1 enhancement-induced excessive autophagy through suppressing FTO-stimulated oxidative stress, which provides novel insights into the mechanisms for the anti-diabetic effect of EGCG.
    Keywords:  (-)-epigallocatechin 3-gallate; Autophagy; FTO; diabetes; oxidative stress; pancreatic β-cell
    DOI:  https://doi.org/10.1080/15548627.2024.2370751
  55. Int J Mol Sci. 2024 Jun 19. pii: 6743. [Epub ahead of print]25(12):
    Early Postnatal Exposure to Midazolam Causes Lasting Histological and Neurobehavioral Deficits via Activation of the mTOR Pathway.
    Jing Xu, Jieqiong Wen, Reilley Paige Mathena, Shreya Singh, Sri Harsha Boppana, Olivia Insun Yoon, Jun Choi, Qun Li, Pengbo Zhang, Cyrus David Mintz.
      Exposure to general anesthetics can adversely affect brain development, but there is little study of sedative agents used in intensive care that act via similar pharmacologic mechanisms. Using quantitative immunohistochemistry and neurobehavioral testing and an established protocol for murine sedation, we tested the hypothesis that lengthy, repetitive exposure to midazolam, a commonly used sedative in pediatric intensive care, interferes with neuronal development and subsequent cognitive function via actions on the mechanistic target of rapamycin (mTOR) pathway. We found that mice in the midazolam sedation group exhibited a chronic, significant increase in the expression of mTOR activity pathway markers in comparison to controls. Furthermore, both neurobehavioral outcomes, deficits in Y-maze and fear-conditioning performance, and neuropathologic effects of midazolam sedation exposure, including disrupted dendritic arborization and synaptogenesis, were ameliorated via treatment with rapamycin, a pharmacologic mTOR pathway inhibitor. We conclude that prolonged, repetitive exposure to midazolam sedation interferes with the development of neural circuitry via a pathologic increase in mTOR pathway signaling during brain development that has lasting consequences for both brain structure and function.
    Keywords:  dendrite morphology; long-term effects; mTOR pathway; midazolam; sedation
    DOI:  https://doi.org/10.3390/ijms25126743
  56. Antioxidants (Basel). 2024 Jun 15. pii: 729. [Epub ahead of print]13(6):
    Liver Cell Mitophagy in Metabolic Dysfunction-Associated Steatotic Liver Disease and Liver Fibrosis.
    Jiaxin Chen, Linge Jian, Yangkun Guo, Chengwei Tang, Zhiyin Huang, Jinhang Gao.
      Metabolic dysfunction-associated steatotic liver disease (MASLD) affects approximately one-third of the global population. MASLD and its advanced-stage liver fibrosis and cirrhosis are the leading causes of liver failure and liver-related death worldwide. Mitochondria are crucial organelles in liver cells for energy generation and the oxidative metabolism of fatty acids and carbohydrates. Recently, mitochondrial dysfunction in liver cells has been shown to play a vital role in the pathogenesis of MASLD and liver fibrosis. Mitophagy, a selective form of autophagy, removes and recycles impaired mitochondria. Although significant advances have been made in understanding mitophagy in liver diseases, adequate summaries concerning the contribution of liver cell mitophagy to MASLD and liver fibrosis are lacking. This review will clarify the mechanism of liver cell mitophagy in the development of MASLD and liver fibrosis, including in hepatocytes, macrophages, hepatic stellate cells, and liver sinusoidal endothelial cells. In addition, therapeutic strategies or compounds related to hepatic mitophagy are also summarized. In conclusion, mitophagy-related therapeutic strategies or compounds might be translational for the clinical treatment of MASLD and liver fibrosis.
    Keywords:  Kupffer cells (KCs); hepatic stellate cells (HSCs); hepatocytes; liver fibrosis; liver sinusoidal endothelial cells (LSECs); macrophages; metabolic dysfunction-associated steatohepatitis (MASH); metabolic dysfunction-associated steatotic liver disease (MASLD); mitochondria; mitophagy
    DOI:  https://doi.org/10.3390/antiox13060729
  57. Int J Mol Sci. 2024 Jun 12. pii: 6468. [Epub ahead of print]25(12):
    The Anthraquinone Derivative C2 Enhances Oxaliplatin-Induced Cell Death and Triggers Autophagy via the PI3K/AKT/mTOR Pathway.
    Yuying Li, Wei Yan, Yu Qin, Liwei Zhang, Sheng Xiao.
      Chemotherapy resistance in cancer is an essential factor leading to high mortality rates. Tumor multidrug resistance arises as a result of the autophagy process. Our previous study found that compound 1-nitro-2 acyl anthraquinone-leucine (C2) exhibited excellent anti-colorectal cancer (CRC) activity involving autophagy and apoptosis-related proteins, whereas its underlying mechanism remains unclear. A notable aspect of this study is how C2 overcomes the multidrug susceptibility of HCT116/L-OHP, a colon cancer cell line that is resistant to both in vitro and in vivo oxaliplatin (trans-/-diaminocyclohexane oxalatoplatinum; L-OHP). In a xenograft tumor mouse model, we discovered that the mixture of C2 and L-OHP reversed the resistance of HCT116/L-OHP cells to L-OHP and inhibited tumor growth; furthermore, C2 down-regulated the gene expression levels of P-gp and BCRP and decreased P-gp's drug efflux activity. It is important to note that while C2 re-sensitized the HCT116/L-OHP cells to L-OHP for apoptosis, it also triggered a protective autophagic pathway. The expression levels of cleaved caspase-3 and Beclin 1 steadily rose. Expression of PI3K, phosphorylated AKT, and mTOR were decreased, while p53 increased. We demonstrated that the anthraquinone derivative C2 acts as an L-OHP sensitizer and reverses resistance to L-OHP in HCT116/L-OHP cells. It suggests that C2 can induce autophagy in HCT116/L-OHP cells by mediating p53 and the PI3K/AKT/mTOR signaling pathway.
    Keywords:  anthraquinone derivative C2; autophagy; multidrug resistance
    DOI:  https://doi.org/10.3390/ijms25126468
  58. bioRxiv. 2024 Jun 12. pii: 2024.06.10.598284. [Epub ahead of print]
    Stat3-mediated Atg7 expression enhances anti-tumor immunity in melanoma.
    Sarah M Zimmerman, Erin Suh, Sofia R Smith, George P Souroullas.
      Epigenetic modifications to DNA and chromatin control oncogenic and tumor suppressive mechanisms in melanoma. EZH2, the catalytic component of the Polycomb repressive complex 2 (PRC2), which mediates methylation of lysine 27 on histone 3 (H3K27me3), can regulate both melanoma initiation and progression. We previously found that mutant Ezh2 Y641F interacts with the immune regulator Stat3 and together they affect anti-tumor immunity. However, given the numerous downstream targets and pathways affected by EZH2, many mechanisms that determine its oncogenic activity remain largely unexplored. Using genetically engineered mouse models we further investigated the role of pathways downstream of EZH2 in melanoma carcinogenesis and identified significant enrichment in several autophagy signatures, along with increased expression of autophagy regulators, such as Atg7. In this study, we investigated the effect of Atg7 on melanoma growth and tumor immunity within the context of an Ezh2 Y641F epigenetic state. We found that expression of Atg7 is largely dependent on Stat3 expression and that deletion of Atg7 slows down melanoma cell growth in vivo , but not in vitro . Atg7 deletion also results in increased CD8+ T cells and reduced myelosuppressive cell infiltration in the tumor microenvironment, suggesting a strong immune system contribution in the role of Atg7 in melanoma progression. These findings highlight the complex interplay between genetic mutations, epigenetic regulators, and autophagy in shaping tumor immunity in melanoma.
    DOI:  https://doi.org/10.1101/2024.06.10.598284
  59. Int J Mol Sci. 2024 Jun 13. pii: 6520. [Epub ahead of print]25(12):
    Cytoprotective Role of Autophagy in CDIP1 Expression-Induced Apoptosis in MCF-7 Breast Cancer Cells.
    Ryuta Inukai, Kanako Mori, Masatoshi Maki, Terunao Takahara, Hideki Shibata.
      Cell death-inducing p53-target protein 1 (CDIP1) is a proapoptotic protein that is normally expressed at low levels and is upregulated by genotoxic and endoplasmic reticulum stresses. CDIP1 has been reported to be localized to endosomes and to interact with several proteins, including B-cell receptor-associated protein 31 (BAP31) and apoptosis-linked gene 2 (ALG-2). However, the cellular and molecular mechanisms underlying CDIP1 expression-induced apoptosis remain unclear. In this study, we first demonstrated that CDIP1 was upregulated after treatment with the anticancer drug adriamycin in human breast cancer MCF-7 cells but was degraded rapidly in the lysosomal pathway. We also demonstrated that treatment with the cyclin-dependent kinase 5 (CDK5) inhibitor roscovitine led to an increase in the electrophoretic mobility of CDIP1. In addition, a phosphomimetic mutation at Ser-32 in CDIP1 resulted in an increase in CDIP1 expression-induced apoptosis. We also found that CDIP1 expression led to the induction of autophagy prior to apoptosis. Treatment of cells expressing CDIP1 with SAR405, an inhibitor of the class III phosphatidylinositol 3-kinase VPS34, caused a reduction in autophagy and promoted apoptosis. Therefore, autophagy is thought to be a defense mechanism against CDIP1 expression-induced apoptosis.
    Keywords:  CDIP1; apoptosis; autophagy; proapoptotic protein
    DOI:  https://doi.org/10.3390/ijms25126520
  60. Mol Metab. 2024 Jun 20. pii: S2212-8778(24)00100-5. [Epub ahead of print] 101969
    Autophagic signaling promotes systems-wide remodeling in skeletal muscle upon oncometabolic stress by D2-HG.
    Yaqi Gao, Kyoungmin Kim, Heidi Vitrac, Rebecca L Salazar, Benjamin D Gould, Daniel Soedkamp, Weston Spivia, Koen Raedschelders, An Q Dinh, Anna G Guzman, Lin Tan, Stavros Azinas, David J R Taylor, Walter Schiffer, Daniel McNavish, Helen B Burks, Roberta A Gottlieb, Philip L Lorenzi, Blake M Hanson, Jennifer E Van Eyk, Heinrich Taegtmeyer, Anja Karlstaedt.
      OBJECTIVES: Cachexia is a metabolic disorder and comorbidity with cancer and heart failure. The syndrome impacts more than thirty million people worldwide, accounting for 20% of all cancer deaths. In acute myeloid leukemia, somatic mutations of the metabolic enzyme isocitrate dehydrogenase 1 and 2 cause the production of the oncometabolite D2-hydroxyglutarate (D2-HG). Increased production of D2-HG is associated with heart and skeletal muscle atrophy, but the mechanistic links between metabolic and proteomic remodeling remain poorly understood. Therefore, we assessed how oncometabolic stress by D2-HG activates autophagy and drives skeletal muscle loss.METHODS: We quantified genomic, metabolomic, and proteomic changes in cultured skeletal muscle cells and mouse models of IDH-mutant leukemia using RNA sequencing, mass spectrometry, and computational modeling.
    RESULTS: D2-HG impairs NADH redox homeostasis in myotubes. Increased NAD+ levels drive activation of nuclear deacetylase Sirt1, which causes deacetylation and activation of LC3, a key regulator of autophagy. Using LC3 mutants, we confirm that deacetylation of LC3 by Sirt1 shifts its distribution from the nucleus into the cytosol, where it can undergo lipidation at pre-autophagic membranes. Sirt1 silencing or p300 overexpression attenuated autophagy activation in myotubes. In vivo, we identified increased muscle atrophy and reduced grip strength in response to D2-HG in male vs. female mice. In male mice, glycolytic intermediates accumulated, and protein expression of oxidative phosphorylation machinery was reduced. In contrast, female animals upregulated the same proteins, attenuating the phenotype in vivo. Network modeling and machine learning algorithms allowed us to identify candidate proteins essential for regulating oncometabolic adaptation in mouse skeletal muscle.
    CONCLUSIONS: Our multi-omics approach exposes new metabolic vulnerabilities in response to D2-HG in skeletal muscle and provides a conceptual framework for identifying therapeutic targets in cachexia.
    Keywords:  Autophagy; Cachexia; Oncometabolism; Systems Biology
    DOI:  https://doi.org/10.1016/j.molmet.2024.101969
  61. Biology (Basel). 2024 May 22. pii: 362. [Epub ahead of print]13(6):
    Exercise, mTOR Activation, and Potential Impacts on the Liver in Rodents.
    Giuliano Moreto Onaka, Marianna Rabelo de Carvalho, Patricia Kubalaki Onaka, Claudiane Maria Barbosa, Paula Felippe Martinez, Silvio Assis de Oliveira-Junior.
      The literature offers a consensus on the association between exercise training (ET) protocols based on the adequate parameters of intensity and frequency, and several adaptive alterations in the liver. Indeed, regular ET can reverse glucose and lipid metabolism disorders, especially from aerobic modalities, which can decrease intrahepatic fat formation. In terms of molecular mechanisms, the regulation of hepatic fat formation would be directly related to the modulation of the mechanistic target of rapamycin (mTOR), which would be stimulated by insulin signaling and Akt activation, from the following three different primary signaling pathways: (I) growth factor, (II) energy/ATP-sensitive, and (III) amino acid-sensitive signaling pathways, respectively. Hyperactivation of the Akt/mTORC1 pathway induces lipogenesis by regulating the action of sterol regulatory element binding protein-1 (SREBP-1). Exercise training interventions have been associated with multiple metabolic and tissue benefits. However, it is worth highlighting that the mTOR signaling in the liver in response to exercise interventions remains unclear. Hepatic adaptive alterations seem to be most outstanding when sustained by chronic interventions or high-intensity exercise protocols.
    Keywords:  cell signaling; exercise; fatty liver; liver; mTOR; metabolism
    DOI:  https://doi.org/10.3390/biology13060362
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