bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2024‒05‒12
58 papers selected by
Viktor Korolchuk, Newcastle University
  1. Inhalation exposure-induced toxicity and disease mediated via mTOR dysregulation.
  2. USP20 deubiquitinates and stabilizes the reticulophagy receptor RETREG1/FAM134B to drive reticulophagy.
  3. A RAB7A phosphoswitch coordinates Rubicon Homology protein regulation of Parkin-dependent mitophagy.
  4. Selective autophagy of the immunoproteasomes suppresses innate inflammation.
  5. Sex Differences In The Interaction Between Alcohol And mTORC1.
  6. Guidelines for the role of autophagy in drug delivery vectors uptake pathways.
  7. Omegasomes control formation, expansion, and closure of autophagosomes.
  8. Golgi defect as a major contributor to lysosomal dysfunction.
  9. Uncharacterized yeast gene YBR238C, an effector of TORC1 signaling in a mitochondrial feedback loop, accelerates cellular aging via HAP4- and RMD9-dependent mechanisms.
  10. Independent organelle and organelle-organelle interactions: essential mechanisms for malignant gynecological cancer cell survival.
  11. Autophagy in Its (Proper) Context: Molecular Basis, Biological Relevance, Pharmacological Modulation, and Lifestyle Medicine.
  12. TAZ deficiency impairs the autophagy-lysosomal pathway through NRF2 dysregulation and lysosomal dysfunction.
  13. The mammalian actin elongation factor ENAH/MENA contributes to autophagosome formation via its actin regulatory function.
  14. Hhatl ameliorates endoplasmic reticulum stress through autophagy by associating with LC3.
  15. Morphodynamical adaptation of the endolysosomal system to stress.
  16. Vaccinia virus subverts xenophagy through phosphorylation and nuclear targeting of p62.
  17. Targeting lysosomal quality control as a therapeutic strategy against aging and diseases.
  18. ORMDL MISLOCALIZATION BY IMPAIRED AUTOPHAGY IN NIEMANN-PICK TYPE C DISEASE LEADS TO INCREASED DE NOVO SPHINGOLIPID BIOSYNTHESIS.
  19. Glucose starvation causes ferroptosis-mediated lysosomal dysfunction.
  20. A mitochondrial surveillance mechanism activated by SRSF2 mutations in hematologic malignancies.
  21. Dysfunction of Avo3, an essential component of target of rapamycin complex 2, induces ubiquitin-proteasome-dependent downregulation of Avo2 in Saccharomyces cerevisiae.
  22. Nuclear mTOR Signaling Orchestrates Transcriptional Programs Underlying Cellular Growth and Metabolism.
  23. Physiological and pathological functions of TMEM106B in neurodegenerative diseases.
  24. The effect of autophagy on hemoporfin-mediated photodynamic therapy in human umbilical vein endothelial cells.
  25. In the fed state, autophagy plays a crucial role in assisting the insect vector Rhodnius prolixus mobilize TAG reserves under forced flight activity.
  26. IRF7 Exacerbates Candida albicans Infection by Compromising CD209-Mediated Phagocytosis and Autophagy-Mediated Killing in Macrophages.
  27. SCFFBXW5-mediated degradation of AQP3 suppresses autophagic cell death through the PDPK1-AKT-MTOR axis in hepatocellular carcinoma cells.
  28. Role of endothelial Raptor in abnormal arteriogenesis after lower limb ischemia in type-2 diabetes.
  29. Autophagy in glioblastoma: A mechanistic perspective.
  30. ATG9B regulates bacterial internalization via actin rearrangement.
  31. Dysfunction of STING Autophagy Degradation in Senescent Nucleus Pulposus Cells Accelerates Intervertebral Disc Degeneration.
  32. Role of autophagy-related genes in liver cancer prognosis.
  33. A mitochondrial surveillance mechanism activated by SRSF2 mutations in hematologic malignancies.
  34. Impaired autophagy in myeloid cells aggravates psoriasis-like skin inflammation through the IL-1β/CXCL2/neutrophil axis.
  35. Rotenone-induced PINK1/Parkin-mediated mitophagy: establishing a silkworm model for Parkinson's disease potential.
  36. Structural and functional characterization of the role of acetylation on the interactions of the human Atg8-family proteins with the autophagy receptor TP53INP2/DOR.
  37. Pathogenic MTOR somatic variant causing focal cortical dysplasia drives hyperexcitability via overactivation of neuronal GluN2C N-methyl-D-aspartate receptors.
  38. YANK2 activated by Fyn promotes glioma tumorigenesis via the mTOR-independent p70S6K activation pathway.
  39. LRRK2 kinase inhibition protects against Parkinson's disease-associated environmental toxicants.
  40. Supramolecular Nanofibers Ameliorate Bleomycin-Induced Pulmonary Fibrosis by Restoring Autophagy.
  41. PCSK9 induces endothelial cell autophagy by regulating the PI3K/ATK pathway in atherosclerotic coronary heart disease.
  42. A new mutation in the Parkinson's-related FBXO7 gene impairs mitochondrial and proteasomal function.
  43. Saponin and Ribosome-Inactivating Protein Synergistically Trigger Lysosome-Dependent Apoptosis by Inhibiting Lysophagy: Potential to Become a New Antitumor Strategy.
  44. NCX1/Ca2+ promotes autophagy and decreases bortezomib activity in multiple myeloma through non-canonical NFκB signaling pathway.
  45. Synergistic induction of autophagy in gastric cancer by targeting CDK4/6 and MEK through AMPK/mTOR pathway.
  46. Overexpression of TRPV1 activates autophagy in human lens epithelial cells under hyperosmotic stress through Ca2+-dependent AMPK/mTOR pathway.
  47. PINK1/Park2-Mediated Mitophagy Relieve Non-Alcoholic Fatty Liver Disease.
  48. Initiation of acute pancreatitis in mice is independent of fusion between lysosomes and zymogen granules.
  49. Low shear stress-induced blockage of autophagic flux impairs endothelial barrier and facilitates atherosclerosis in mice.
  50. In-silico Codon Context and Synonymous Usage Analysis of Genes for Molecular Mechanisms Inducing Autophagy and Apoptosis with Reference to Neurodegenerative Disorders.
  51. The Suppression of Ubiquitin C-Terminal Hydrolase L1 Promotes the Transdifferentiation of Auditory Supporting Cells into Hair Cells by Regulating the mTOR Pathway.
  52. Modulating Synovial Macrophage Pyroptosis and Mitophagy Interactions to Mitigate Osteoarthritis Progression using Functionalized Nanoparticles.
  53. Verteporfin suppressed mitophagy via PINK1/parkin pathway in endometrial cancer.
  54. Perinuclear damage from nuclear envelope deterioration elicits stress responses that contribute to LMNA cardiomyopathy.
  55. Fasting-induced RNF152 resensitizes gallbladder cancer cells to gemcitabine by inhibiting mTORC1-mediated glycolysis.
  56. Structural basis for the intracellular regulation of ferritin degradation.
  57. Caloric restriction mitigates age-associated senescence characteristics in subcutaneous adipose tissue-derived stem cells.
  58. EPB41L4A-AS1 is required to maintain basal autophagy to modulates Aβ clearance.
  1. Exp Biol Med (Maywood). 2024 ;249 10135
    Inhalation exposure-induced toxicity and disease mediated via mTOR dysregulation.
    Akshada Shinde, Jonathan Shannahan.
      Environmental air pollution is a global health concern, associated with multiple respiratory and systemic diseases. Epidemiological supports continued urbanization and industrialization increasing the prevalence of inhalation exposures. Exposure to these inhaled pollutants induces toxicity via activation of numerous cellular mechanisms including oxidative stress, autophagy, disrupted cellular metabolism, inflammation, tumorigenesis, and others contributing to disease development. The mechanistic target of rapamycin (mTOR) is a key regulator involved in various cellular processes related to the modulation of metabolism and maintenance of homeostasis. Dysregulation of mTOR occurs following inhalation exposures and has also been implicated in many diseases such as cancer, obesity, cardiovascular disease, diabetes, asthma, and neurodegeneration. Moreover, mTOR plays a fundamental role in protein transcription and translation involved in many inflammatory and autoimmune diseases. It is necessary to understand inhalation exposure-induced dysregulation of mTOR since it is key regulator which may contribute to numerous disease processes. This mini review evaluates the available literature regarding several types of inhalation exposure and their impacts on mTOR signaling. Particularly we focus on the mTOR signaling pathway related outcomes of autophagy, lipid metabolism, and inflammation. Furthermore, we will examine the implications of dysregulated mTOR pathway in exposure-induced diseases. Throughout this mini review, current gaps will be identified related to exposure-induced mTOR dysregulation which may enable the targeting of mTOR signaling for the development of therapeutics.
    Keywords:  autophagy; inflammation; inhalation toxicology; lipid homeostasis; lung disease; mTOR; metabolism
    DOI:  https://doi.org/10.3389/ebm.2024.10135
  2. Autophagy. 2024 May 05.
    USP20 deubiquitinates and stabilizes the reticulophagy receptor RETREG1/FAM134B to drive reticulophagy.
    Man Zhang, Zhangshun Wang, Qing Zhao, Qian Yang, Jieyun Bai, Cuiwei Yang, Zai-Rong Zhang, Yanfen Liu.
      The endoplasmic reticulum (ER) serves as a hub for various essential cellular processes, and maintaining ER homeostasis is essential for cell function. Reticulophagy is a selective process that removes impaired ER subdomains through autophagosome and lysosomal degradation. While the involvement of ubiquitination in autophagy regulation is well-established, its role in reticulophagy remains unclear. In this study, we screened deubiquitinating enzymes (DUBs) involved in reticulophagy and identified USP20 (ubiquitin specific peptidase 20) as a key regulator of reticulophagy under starvation conditions. USP20 specifically cleaves K48- and K63-linked ubiquitin chains on the reticulophagy receptor RETREG1/FAM134B (reticulophagy regulator 1), thereby stabilizing the substrate and promoting reticulophagy. Remarkably, despite lacking a transmembrane domain, USP20 is recruited to the ER through its interaction with VAPs (VAMP associated proteins). VAPs facilitate the recruitment of early autophagy proteins, including WIPI2 (WD repeat domain, phosphoinositide interacting 2), to specific ER subdomains, where USP20 and RETREG1 are enriched. This recruitment of WIPI2 and other proteins plays a crucial role in facilitating RETREG1-mediated reticulophagy in response to nutrient deprivation. These findings highlight the critical role of USP20 in maintaining ER homeostasis by deubiquitinating and stabilizing RETREG1 at distinct ER subdomains, where USP20 further recruits VAPs and promotes efficient reticulophagy.
    Keywords:  Autophagy; LC3; Vaps; deubiquitination; endoplasmic reticulum
    DOI:  https://doi.org/10.1080/15548627.2024.2347103
  3. J Cell Biol. 2024 Jul 01. pii: e202309015. [Epub ahead of print]223(7):
    A RAB7A phosphoswitch coordinates Rubicon Homology protein regulation of Parkin-dependent mitophagy.
    Dan A Tudorica, Bishal Basak, Alexia S Puerta Cordova, Grace Khuu, Kevin Rose, Michael Lazarou, Erika L F Holzbaur, James H Hurley.
      Activation of PINK1 and Parkin in response to mitochondrial damage initiates a response that includes phosphorylation of RAB7A at Ser72. Rubicon is a RAB7A binding negative regulator of autophagy. The structure of the Rubicon:RAB7A complex suggests that phosphorylation of RAB7A at Ser72 would block Rubicon binding. Indeed, in vitro phosphorylation of RAB7A by TBK1 abrogates Rubicon:RAB7A binding. Pacer, a positive regulator of autophagy, has an RH domain with a basic triad predicted to bind an introduced phosphate. Consistent with this, Pacer-RH binds to phosho-RAB7A but not to unphosphorylated RAB7A. In cells, mitochondrial depolarization reduces Rubicon:RAB7A colocalization whilst recruiting Pacer to phospho-RAB7A-positive puncta. Pacer knockout reduces Parkin mitophagy with little effect on bulk autophagy or Parkin-independent mitophagy. Rescue of Parkin-dependent mitophagy requires the intact pRAB7A phosphate-binding basic triad of Pacer. Together these structural and functional data support a model in which the TBK1-dependent phosphorylation of RAB7A serves as a switch, promoting mitophagy by relieving Rubicon inhibition and favoring Pacer activation.
    DOI:  https://doi.org/10.1083/jcb.202309015
  4. Autophagy. 2024 May 08.
    Selective autophagy of the immunoproteasomes suppresses innate inflammation.
    Jiao Zhou, Huihui Li, Kefeng Lu.
      Immunoproteasomes are involved in various inflammatory diseases. Upon stimulation, standard constitutive proteasomes are partially replaced by newly formed immunoproteasomes that promote inflammatory responses. How the upregulated immunoproteasomes are cleared to constrain hyper-inflammation is unknown. Recently, our studies showed that the pan-FGFR inhibitor LY2874455 efficiently activates macroautophagy/autophagy in macrophages, leading to the degradation of the immunoproteasomes. Immunoproteasome subunits are ubiquitinated and recognized by the selective autophagy receptor SQSTM1/p62. LY2874455 suppresses inflammation induced by lipopolysaccharide both in vivo and in vitro through autophagic degradation of the immunoproteasomes. In summary, our work uncovers a mechanism of inflammation suppression by autophagy in macrophages.
    Keywords:  Autophagosome; FGFR; immunoproteasome; inflammation; macrophage
    DOI:  https://doi.org/10.1080/15548627.2024.2353437
  5. bioRxiv. 2024 Apr 25. pii: 2023.10.04.560781. [Epub ahead of print]
    Sex Differences In The Interaction Between Alcohol And mTORC1.
    Yann Ehinger, Khanhky Phamluong, Dorit Ron.
      The kinase mechanistic target of rapamycin complex 1 (mTORC1) plays an essential role in learning and memory by promoting mRNA to protein translation of a subset of synaptic proteins at dendrites. We generated a large body of data in male rodents indicating that mTORC1 is critically involved in mechanisms that promote numerous adverse behaviors associated with alcohol use disorder (AUD) including heavy alcohol use. For example, we found that mTORC1 is activated in the nucleus accumbens (NAc) and orbitofrontal cortex (OFC) of male mice and rats that were subjected to 7 weeks of intermittent access to 20% alcohol two-bottle choice (IA20%2BC). We further showed that systemic or intra-NAc administration of the selective mTORC1 inhibitor, rapamycin, decreases alcohol seeking and drinking, whereas intra-OFC administration of rapamycin reduces alcohol seeking and habit in male rats. This study aimed to assess mTORC1 activation in these corticostriatal regions of female mice and to determine whether the selective mTORC1 inhibitor, rapamycin, can be used to reduce heavy alcohol use in female mice. We found that mTORC1 is not activated by 7 weeks of intermittent 20% alcohol binge drinking and withdrawal in the NAc and OFC. Like in males, mTORC1 signaling was not activated by chronic alcohol intake and withdrawal in the medial prefrontal cortex (mPFC) of female mice. Interestingly, Pearson correlation comparisons revealed that the basal level of mTORC1 activation between the two prefrontal regions, OFC and mPFC were correlated and that the drinking profile predicts the level of mTORC1 activation in the mPFC after 4-hour binge drinking. Finally, we report that administration of rapamycin does not attenuate heavy alcohol drinking in female animals. Together, our results suggest a sex-dependent contribution of mTORC1 to the neuroadaptation that drives alcohol use and abuse.
    DOI:  https://doi.org/10.1101/2023.10.04.560781
  6. Heliyon. 2024 May 15. 10(9): e30238
    Guidelines for the role of autophagy in drug delivery vectors uptake pathways.
    Moataz Dowaidar.
      The process of autophagy refers to the intracellular absorption of cytoplasm (such as proteins, nucleic acids, tiny molecules, complete organelles, and so on) into the lysosome, followed by the breakdown of that cytoplasm. The majority of cellular proteins are degraded by a process called autophagy, which is both a naturally occurring activity and one that may be induced by cellular stress. Autophagy is a system that can save cells' integrity in stressful situations by restoring metabolic basics and getting rid of subcellular junk. This happens as a component of an endurance response. This mechanism may have an effect on disease, in addition to its contribution to the homeostasis of individual cells and tissues as well as the control of development in higher species. The main aim of this study is to discuss the guidelines for the role of autophagy in drug delivery vector uptake pathways. In this paper, we discuss the meaning and concept of autophagy, the mechanism of autophagy, the role of autophagy in drug delivery vectors, autophagy-modulating drugs, nanostructures for delivery systems of autophagy modulators, etc. Later in this paper, we talk about how to deliver chemotherapeutics, siRNA, and autophagy inducers and inhibitors. We also talk about how hard it is to make a drug delivery system that takes nanocarriers' roles as autophagy modulators into account.
    Keywords:  Autophagy; Cellular Trafficking; Drug delivery; Extracellular Vesicles; Nano-delivery Systems; Nanocarriers; Nanotechnology; Organelle Specificity; Selective Autophagy; Targeted Therapy; Therapeutic Nanoparticles; Uptake pathways; Vectors
    DOI:  https://doi.org/10.1016/j.heliyon.2024.e30238
  7. Bioessays. 2024 May 09. e2400038
    Omegasomes control formation, expansion, and closure of autophagosomes.
    Viola Nähse, Harald Stenmark, Kay O Schink.
      Autophagy, an essential cellular process for maintaining cellular homeostasis and eliminating harmful cytoplasmic objects, involves the de novo formation of double-membraned autophagosomes that engulf and degrade cellular debris, protein aggregates, damaged organelles, and pathogens. Central to this process is the phagophore, which forms from donor membranes rich in lipids synthesized at various cellular sites, including the endoplasmic reticulum (ER), which has emerged as a primary source. The ER-associated omegasomes, characterized by their distinctive omega-shaped structure and accumulation of phosphatidylinositol 3-phosphate (PI3P), play a pivotal role in autophagosome formation. Omegasomes are thought to serve as platforms for phagophore assembly by recruiting essential proteins such as DFCP1/ZFYVE1 and facilitating lipid transfer to expand the phagophore. Despite the critical importance of phagophore biogenesis, many aspects remain poorly understood, particularly the complete range of proteins involved in omegasome dynamics, and the detailed mechanisms of lipid transfer and membrane contact site formation.
    Keywords:  DFCP1; FYVE domain; PI3P; omegasome; phagophore
    DOI:  https://doi.org/10.1002/bies.202400038
  8. Front Cell Dev Biol. 2024 ;12 1386149
    Golgi defect as a major contributor to lysosomal dysfunction.
    Sarah R Akaaboune, Yanzhuang Wang.
      The Golgi apparatus plays a crucial role in lysosome biogenesis and the delivery of lysosomal enzymes, essential for maintaining cellular homeostasis and ensuring cell survival. Deficiencies in Golgi structure and function can profoundly impact lysosomal homeostasis, leading to various lysosomal storage diseases and neurodegenerative disorders. In this review, we highlight the role of the Golgi Reassembly Stacking Proteins (GRASPs) in the formation and function of the Golgi apparatus, emphasizing the current understanding of the association between the Golgi apparatus, lysosomes, and lysosomal storage diseases. Additionally, we discuss how Golgi dysfunction leads to the secretion of lysosomal enzymes. This review aims to serve as a concise resource, offering insights into Golgi structure, function, disease-related defects, and their consequential effects on lysosomal biogenesis and function. By highlighting Golgi defects as an underappreciated contributor to lysosomal dysfunction across various diseases, we aim to enhance comprehension of these intricate cellular processes.
    Keywords:  GRASP55; GRASP65; Golgi; HexA; lysosomal storage diseases; lysosome; neurodegenerative diseases; secretion
    DOI:  https://doi.org/10.3389/fcell.2024.1386149
  9. Elife. 2024 May 07. pii: RP92178. [Epub ahead of print]12
    Uncharacterized yeast gene YBR238C, an effector of TORC1 signaling in a mitochondrial feedback loop, accelerates cellular aging via HAP4- and RMD9-dependent mechanisms.
    Mohammad Alfatah, Jolyn Jia Jia Lim, Yizhong Zhang, Arshia Naaz, Trishia Yi Ning Cheng, Sonia Yogasundaram, Nashrul Afiq Faidzinn, Jovian Jing Lin, Birgit Eisenhaber, Frank Eisenhaber.
      Uncovering the regulators of cellular aging will unravel the complexity of aging biology and identify potential therapeutic interventions to delay the onset and progress of chronic, aging-related diseases. In this work, we systematically compared genesets involved in regulating the lifespan of Saccharomyces cerevisiae (a powerful model organism to study the cellular aging of humans) and those with expression changes under rapamycin treatment. Among the functionally uncharacterized genes in the overlap set, YBR238C stood out as the only one downregulated by rapamycin and with an increased chronological and replicative lifespan upon deletion. We show that YBR238C and its paralog RMD9 oppositely affect mitochondria and aging. YBR238C deletion increases the cellular lifespan by enhancing mitochondrial function. Its overexpression accelerates cellular aging via mitochondrial dysfunction. We find that the phenotypic effect of YBR238C is largely explained by HAP4- and RMD9-dependent mechanisms. Furthermore, we find that genetic- or chemical-based induction of mitochondrial dysfunction increases TORC1 (Target of Rapamycin Complex 1) activity that, subsequently, accelerates cellular aging. Notably, TORC1 inhibition by rapamycin (or deletion of YBR238C) improves the shortened lifespan under these mitochondrial dysfunction conditions in yeast and human cells. The growth of mutant cells (a proxy of TORC1 activity) with enhanced mitochondrial function is sensitive to rapamycin whereas the growth of defective mitochondrial mutants is largely resistant to rapamycin compared to wild type. Our findings demonstrate a feedback loop between TORC1 and mitochondria (the TORC1-MItochondria-TORC1 (TOMITO) signaling process) that regulates cellular aging processes. Hereby, YBR238C is an effector of TORC1 modulating mitochondrial function.
    Keywords:  S. cerevisiae; cellular aging; genetics; genomics; human; lifespan; mitochondria; nutrient signaling; target of rapamycin complex 1; uncharacterized genes
    DOI:  https://doi.org/10.7554/eLife.92178
  10. Front Immunol. 2024 ;15 1393852
    Independent organelle and organelle-organelle interactions: essential mechanisms for malignant gynecological cancer cell survival.
    Ying Shen, Qiao-Chu Chen, Chen-Yu Li, Feng-Juan Han.
      Different eukaryotic cell organelles (e.g., mitochondria, endoplasmic reticulum, lysosome) are involved in various cancer processes, by dominating specific cellular activities. Organelles cooperate, such as through contact points, in complex biological activities that help the cell regulate energy metabolism, signal transduction, and membrane dynamics, which influence survival process. Herein, we review the current studies of mechanisms by which mitochondria, endoplasmic reticulum, and lysosome are related to the three major malignant gynecological cancers, and their possible therapeutic interventions and drug targets. We also discuss the similarities and differences of independent organelle and organelle-organelle interactions, and their applications to the respective gynecological cancers; mitochondrial dynamics and energy metabolism, endoplasmic reticulum dysfunction, lysosomal regulation and autophagy, organelle interactions, and organelle regulatory mechanisms of cell death play crucial roles in cancer tumorigenesis, progression, and response to therapy. Finally, we discuss the value of organelle research, its current problems, and its future directions.
    Keywords:  endoplasmic reticulum; lysosome; malignant gynecological cancer; mitochondria; organelle
    DOI:  https://doi.org/10.3389/fimmu.2024.1393852
  11. Int J Biol Sci. 2024 ;20(7): 2532-2554
    Autophagy in Its (Proper) Context: Molecular Basis, Biological Relevance, Pharmacological Modulation, and Lifestyle Medicine.
    Miguel A Ortega, Oscar Fraile-Martinez, Diego de Leon-Oliva, Diego Liviu Boaru, Laura Lopez-Gonzalez, Cielo García-Montero, Miguel Angel Alvarez-Mon, Luis G Guijarro, Diego Torres-Carranza, Miguel A Saez, Raul Diaz-Pedrero, Agustin Albillos, Melchor Alvarez-Mon.
      Autophagy plays a critical role in maintaining cellular homeostasis and responding to various stress conditions by the degradation of intracellular components. In this narrative review, we provide a comprehensive overview of autophagy's cellular and molecular basis, biological significance, pharmacological modulation, and its relevance in lifestyle medicine. We delve into the intricate molecular mechanisms that govern autophagy, including macroautophagy, microautophagy and chaperone-mediated autophagy. Moreover, we highlight the biological significance of autophagy in aging, immunity, metabolism, apoptosis, tissue differentiation and systemic diseases, such as neurodegenerative or cardiovascular diseases and cancer. We also discuss the latest advancements in pharmacological modulation of autophagy and their potential implications in clinical settings. Finally, we explore the intimate connection between lifestyle factors and autophagy, emphasizing how nutrition, exercise, sleep patterns and environmental factors can significantly impact the autophagic process. The integration of lifestyle medicine into autophagy research opens new avenues for promoting health and longevity through personalized interventions.
    Keywords:  ATG proteins; aging; autophagosome; lifestyle habits; pharmacological modulation
    DOI:  https://doi.org/10.7150/ijbs.95122
  12. Int J Biol Sci. 2024 ;20(7): 2592-2606
    TAZ deficiency impairs the autophagy-lysosomal pathway through NRF2 dysregulation and lysosomal dysfunction.
    Hyo Kyeong Kim, Hana Jeong, Mi Gyeong Jeong, Hee Yeon Won, Gibbeum Lee, Soo Han Bae, Miso Nam, Sung Hoon Lee, Geum-Sook Hwang, Eun Sook Hwang.
      Transcriptional coactivator with a PDZ-binding motif (TAZ) plays a key role in normal tissue homeostasis and tumorigenesis through interaction with several transcription factors. In particular, TAZ deficiency causes abnormal alveolarization and emphysema, and persistent TAZ overexpression contributes to lung cancer and pulmonary fibrosis, suggesting the possibility of a complex mechanism of TAZ function. Recent studies suggest that nuclear factor erythroid 2-related factor 2 (NRF2), an antioxidant defense system, induces TAZ expression during tumorigenesis and that TAZ also activates the NRF2-mediated antioxidant pathway. We thus thought to elucidate the cross-regulation of TAZ and NRF2 and the underlying molecular mechanisms and functions. TAZ directly interacted with NRF2 through the N-terminal domain and suppressed the transcriptional activity of NRF2 by preventing NRF2 from binding to DNA. In addition, the return of NRF2 to basal levels after signaling was inhibited in TAZ deficiency, resulting in sustained nuclear NRF2 levels and aberrantly increased expression of NRF2 targets. TAZ deficiency failed to modulate optimal NRF2 signaling and concomitantly impaired lysosomal acidification and lysosomal enzyme function, accumulating the abnormal autophagy vesicles and reactive oxygen species and causing protein oxidation and cellular damage in the lungs. TAZ restoration to TAZ deficiency normalized dysregulated NRF2 signaling and aberrant lysosomal function and triggered the normal autophagy-lysosomal pathway. Therefore, TAZ is indispensable for the optimal regulation of NRF2-mediated autophagy-lysosomal pathways and for preventing pulmonary damage caused by oxidative stress and oxidized proteins.
    Keywords:  NRF2; TAZ; autophagy; lysosomal acidification; oxidative stress
    DOI:  https://doi.org/10.7150/ijbs.88897
  13. Autophagy. 2024 May 05.
    The mammalian actin elongation factor ENAH/MENA contributes to autophagosome formation via its actin regulatory function.
    Yueheng Li, Yafei Zhang, Menghui Wang, Junhui Su, Xinjue Dong, Yuqi Yang, Hongshan Wang, QingQuan Li.
      Macroautophagy/autophagy is a catabolic process crucial for degrading cytosolic components and damaged organelles to maintain cellular homeostasis, enabling cells to survive in extreme extracellular environments. ENAH/MENA, a member of the Ena/VASP protein family, functions as a highly efficient actin elongation factor. In this study, our objective was to explore the role of ENAH in the autophagy process. Initially, we demonstrated that depleting ENAH in cancer cells inhibits autophagosome formation. Subsequently, we observed ENAH's colocalization with MAP1LC3/LC3 during tumor cell starvation, dependent on actin cytoskeleton polymerization and the interaction between ENAH and BECN1 (beclin 1). Additionally, mammalian ATG9A formed a ring-like structure around ENAH-LC3 puncta during starvation, relying on actin cytoskeleton polymerization. Furthermore, ENAH's EVH1 and EVH2 domains were found to be indispensable for its colocalization with LC3 and BECN1, while the PRD domain played a crucial role in the formation of the ATG9A ring. Finally, our study revealed ENAH-led actin comet tails in autophagosome trafficking. In conclusion, our findings provide initial insights into the regulatory role of the mammalian actin elongation factor ENAH in autophagy.
    Keywords:  Actin cytoskeleton; BECN1; ENAH; Ena/Vasp; autophagy; live cell imaging
    DOI:  https://doi.org/10.1080/15548627.2024.2347105
  14. J Biol Chem. 2024 May 03. pii: S0021-9258(24)01836-2. [Epub ahead of print] 107335
    Hhatl ameliorates endoplasmic reticulum stress through autophagy by associating with LC3.
    Xingjuan Shi, Jiayu Yao, Yexi Huang, Yushan Wang, Xuan Jiang, Ziwen Wang, Mingming Zhang, Yu Zhang, Xiangdong Liu.
      Endoplasmic reticulum (ER) stress, a common cellular stress response induced by various factors that interfere with cellular homeostasis, may trigger cell apoptosis. Autophagy is an important and conserved mechanism for eliminating aggregated proteins and maintaining protein stability of cells, which is closely associated with ER stress and ER stress-induced apoptosis. In this paper, we report for the first time that Hhatl, an ER-resident protein, is downregulated in response to ER stress. Hhatl overexpression alleviated ER stress and ER stress induced apoptosis in cells treated with tunicamycin or thapsigargin, whereas Hhatl knockdown exacerbated ER stress and apoptosis. Further study showed that Hhatl attenuates ER stress by promoting autophagic flux. Mechanistically, we found that Hhatl promotes autophagy by associating with autophagic protein LC3 (microtubule-associated protein 1A/1B-light chain 3) via the conserved LC3-interacting region (LIR) motif. Noticeably, the LIR motif was essential for Hhatl-regulated promotion of autophagy and reduction of ER stress. These findings demonstrate that Hhatl ameliorates ER stress via autophagy activation by interacting with LC3, thereby alleviating cellular pressure. The study indicates that pharmacological or genetic regulation of Hhatl-autophagy signaling might be potential for mediating ER stress and related diseases.
    Keywords:  ER stress; Hhatl; LC3; autophagy
    DOI:  https://doi.org/10.1016/j.jbc.2024.107335
  15. FEBS J. 2024 May 05.
    Morphodynamical adaptation of the endolysosomal system to stress.
    Juliane Da Graça, Cédric Delevoye, Etienne Morel.
      In eukaryotes, the spatiotemporal control of endolysosomal organelles is central to the maintenance of homeostasis. By providing an interface between the cytoplasm and external environment, the endolysosomal system is placed at the forefront of the response to a wide range of stresses faced by cells. Endosomes are equipped with a dedicated set of membrane-associated proteins that ensure endosomal functions as well as crosstalk with the secretory or the autophagy pathways. Morphodynamical processes operate through local spatialization of subdomains, enabling specific remodeling and membrane contact capabilities. Consequently, the plasticity of endolysosomal organelles can be considered a robust and flexible tool exploited by cells to cope with homeostatic deviations. In this review, we provide insights into how the cellular responses to various stresses (osmotic, UV, nutrient deprivation, or pathogen infections) rely on the adaptation of the endolysosomal system morphodynamics.
    Keywords:  autophagy; endocytic pathway; endolysosomes; endosomes; lysosome‐related organelles; membrane dynamics and contact sites; organelles; pathogen infection; plasma membrane; stress response
    DOI:  https://doi.org/10.1111/febs.17154
  16. J Cell Biol. 2024 Jun 03. pii: e202104129. [Epub ahead of print]223(6):
    Vaccinia virus subverts xenophagy through phosphorylation and nuclear targeting of p62.
    Melanie Krause, Jerzy Samolej, Artur Yakimovich, Janos Kriston-Vizi, Moona Huttunen, Samuel Lara-Reyna, Eva-Maria Frickel, Jason Mercer.
      Autophagy is an essential degradation program required for cell homeostasis. Among its functions is the engulfment and destruction of cytosolic pathogens, termed xenophagy. Not surprisingly, many pathogens use various strategies to circumvent or co-opt autophagic degradation. For poxviruses, it is known that infection activates autophagy, which however is not required for successful replication. Even though these complex viruses replicate exclusively in the cytoplasm, autophagy-mediated control of poxvirus infection has not been extensively explored. Using the prototypic poxvirus, vaccinia virus (VACV), we show that overexpression of the xenophagy receptors p62, NDP52, and Tax1Bp1 restricts poxvirus infection. While NDP52 and Tax1Bp1 were degraded, p62 initially targeted cytoplasmic virions before being shunted to the nucleus. Nuclear translocation of p62 was dependent upon p62 NLS2 and correlated with VACV kinase mediated phosphorylation of p62 T269/S272. This suggests that VACV targets p62 during the early stages of infection to avoid destruction and further implies that poxviruses exhibit multi-layered control of autophagy to facilitate cytoplasmic replication.
    DOI:  https://doi.org/10.1083/jcb.202104129
  17. Med Res Rev. 2024 May 06.
    Targeting lysosomal quality control as a therapeutic strategy against aging and diseases.
    Yuchen He, Yishu Fan, Xenab Ahmadpoor, Yumin Wang, Zhong Alan Li, Weihong Zhu, Hang Lin.
      Previously, lysosomes were primarily referred to as the digestive organelles and recycling centers within cells. Recent discoveries have expanded the lysosomal functional scope and revealed their critical roles in nutrient sensing, epigenetic regulation, plasma membrane repair, lipid transport, ion homeostasis, and cellular stress response. Lysosomal dysfunction is also found to be associated with aging and several diseases. Therefore, function of macroautophagy, a lysosome-dependent intracellular degradation system, has been identified as one of the updated twelve hallmarks of aging. In this review, we begin by introducing the concept of lysosomal quality control (LQC), which is a cellular machinery that maintains the number, morphology, and function of lysosomes through different processes such as lysosomal biogenesis, reformation, fission, fusion, turnover, lysophagy, exocytosis, and membrane permeabilization and repair. Next, we summarize the results from studies reporting the association between LQC dysregulation and aging/various disorders. Subsequently, we explore the emerging therapeutic strategies that target distinct aspects of LQC for treating diseases and combatting aging. Lastly, we underscore the existing knowledge gap and propose potential avenues for future research.
    Keywords:  aging; autoimmune diseases; cancer; degenerative diseases; lysosomal quality control
    DOI:  https://doi.org/10.1002/med.22047
  18. J Lipid Res. 2024 May 06. pii: S0022-2275(24)00061-0. [Epub ahead of print] 100556
    ORMDL MISLOCALIZATION BY IMPAIRED AUTOPHAGY IN NIEMANN-PICK TYPE C DISEASE LEADS TO INCREASED DE NOVO SPHINGOLIPID BIOSYNTHESIS.
    Ryan D R Brown, Usha Mahawar, Binks W Wattenberg, Sarah Spiegel.
      Niemann-Pick type C1 (NPC1) disease is rare neurodegenerative cholesterol and sphingolipid storage disorder primarily due to mutations in the cholesterol-trafficking protein NPC1. In addition to catabolic-derived sphingolipids, NPC1 dysfunction also leads to an increase in de novo sphingolipid biosynthesis, yet little is known of the cellular mechanism involved. Although deletion of NPC1 or inhibition of the NPC1 sterol binding domain enhanced de novo sphingolipid biosynthesis, surprisingly levels of the ORMDLs, the regulatory subunits of serine palmitoyltransferase (SPT), the rate-limiting step in sphingolipid biosynthesis, were also greatly increased. Nevertheless, less ORMDL was bound in the SPT-ORMDL complex despite elevated ceramide levels. Instead, ORMDL colocalized with p62, the selective autophagy receptor, and accumulated in stalled autophagosomes due to defective autophagy in NPC1 disease cells. Restoration of autophagic flux with N-acetyl-L-leucine in NPC1 deleted cells decreased ORMDL accumulation in autophagosomes and reduced de novo sphingolipid biosynthesis and their accumulation. This study revealed a previously unknown link between de novo sphingolipid biosynthesis, ORMDL and autophagic defects present in NCP1 disease. In addition, we provide further evidence and mechanistic insight for the beneficial role of N-acetyl-L-leucine treatment for NPC1 disease that is presently awaiting approval from the Food and Drug Administration and the European Medicines Agency.
    Keywords:  NPC1; ORMDL; sphingolipid biosynthesis
    DOI:  https://doi.org/10.1016/j.jlr.2024.100556
  19. iScience. 2024 May 17. 27(5): 109735
    Glucose starvation causes ferroptosis-mediated lysosomal dysfunction.
    Kenji Miki, Mikako Yagi, Dongchon Kang, Yuya Kunisaki, Koji Yoshimoto, Takeshi Uchiumi.
      Lysosomes, the hub of metabolic signaling, are associated with various diseases and participate in autophagy by supplying nutrients to cells under nutrient starvation. However, their function and regulation under glucose starvation remain unclear and are studied herein. Under glucose starvation, lysosomal protein expression decreased, leading to the accumulation of damaged lysosomes. Subsequently, cell death occurred via ferroptosis and iron accumulation due to DMT1 degradation. GPX4, a key factor in ferroptosis inhibition located on the outer membrane of lysosomes, accumulated in lysosomes, especially under glucose starvation, to protect cells from ferroptosis. ALDOA, GAPDH, NAMPT, and PGK1 are also located on the outer membrane of lysosomes and participate in lysosomal function. These enzymes did not function effectively under glucose starvation, leading to lysosomal dysfunction and ferroptosis. These findings may facilitate the treatment of lysosomal-related diseases.
    Keywords:  Cell biology; Cellular physiology; Functional aspects of cell biology
    DOI:  https://doi.org/10.1016/j.isci.2024.109735
  20. J Clin Invest. 2024 May 07. pii: e175619. [Epub ahead of print]
    A mitochondrial surveillance mechanism activated by SRSF2 mutations in hematologic malignancies.
    Xiaolei Liu, Sudhish A Devadiga, Robert F Stanley, Ryan M Morrow, Kevin A Janssen, Mathieu Quesnel-Vallières, Oz Pomp, Adam A Moverley, Chenchen Li, Nicolas Skuli, Martin P Carroll, Jian Huang, Douglas C Wallace, Kristen W Lynch, Omar Abdel-Wahab, Peter S Klein.
      Splicing factor mutations are common in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), but how they alter cellular functions is unclear. We show that the pathogenic SRSF2P95H/+ mutation disrupts the splicing of mitochondrial mRNAs, impairs mitochondrial complex I function, and robustly increases mitophagy. We also identified a mitochondrial surveillance mechanism by which mitochondrial dysfunction modifies splicing of the mitophagy activator PINK1 to remove a poison intron, increasing the stability and abundance of PINK1 mRNA and protein. SRSF2P95H-induced mitochondrial dysfunction increased PINK1 expression through this mechanism, which is essential for survival of SRSF2P95H/+ cells. Inhibition of splicing with a glycogen synthase kinase 3 inhibitor promoted retention of the poison intron, impairing mitophagy and activating apoptosis in SRSF2P95H/+ cells. These data reveal a homeostatic mechanism for sensing mitochondrial stress through PINK1 splicing and identify increased mitophagy as a disease marker and a therapeutic vulnerability in SRSF2P95H mutant MDS and AML.
    Keywords:  Autophagy; Hematology; Leukemias; Mitochondria; Oncology
    DOI:  https://doi.org/10.1172/JCI175619
  21. Biochem Biophys Res Commun. 2024 May 03. pii: S0006-291X(24)00581-3. [Epub ahead of print]717 150045
    Dysfunction of Avo3, an essential component of target of rapamycin complex 2, induces ubiquitin-proteasome-dependent downregulation of Avo2 in Saccharomyces cerevisiae.
    Pao-Kuang Chen, Yu-Jung Chang, Yu-Wen Chou, Mei-Yu Chen.
      The ubiquitin-proteasome system (UPS) plays a key role in maintaining cellular protein homeostasis and participates in modulating various cellular functions. Target of rapamycin (TOR), a highly conserved Ser/Thr kinase found across species from yeasts to humans, forms two multi-protein complexes, TORC1 and TORC2, to orchestrate cellular processes crucial for optimal growth, survival, and stress responses. While UPS-mediated regulation of mammalian TOR complexes has been documented, the ubiquitination of yeast TOR complexes remains largely unexplored. Here we report a functional interplay between the UPS and TORC2 in Saccharomyces cerevisiae. Using avo3-2ts, a temperature-sensitive mutant of the essential TORC2 component Avo3 exhibiting TORC2 defects at restrictive temperatures, we obtained evidence for UPS-dependent protein degradation and downregulation of the TORC2 component Avo2. Our results established the involvement of the E3 ubiquitin ligase Ubr1 and its catalytic activity in mediating Avo2 degradation in cells with defective Avo3. Coimmunoprecipitation revealed the interaction between Avo2 and Ubr1, indicating Avo2 as a potential substrate of Ubr1. Furthermore, depleting Ubr1 rescued the growth of avo3-2ts cells at restrictive temperatures, suggesting an essential role of Avo2 in sustaining cell viability under heat stress and/or TORC2 dysfunction. This study uncovers a role of UPS in yeast TORC2 regulation, highlighting the impact of protein degradation control on cellular signaling.
    Keywords:  E3 ubiquitin ligase; Protein degradation; TORC2; Ubiquitination; Yeast
    DOI:  https://doi.org/10.1016/j.bbrc.2024.150045
  22. Cells. 2024 May 03. pii: 781. [Epub ahead of print]13(9):
    Nuclear mTOR Signaling Orchestrates Transcriptional Programs Underlying Cellular Growth and Metabolism.
    Tinghan Zhao, Jialin Fan, Ahmed Abu-Zaid, Stephen K Burley, X F Steven Zheng.
      mTOR is a central regulator of cell growth and metabolism in response to mitogenic and nutrient signals. Notably, mTOR is not only found in the cytoplasm but also in the nucleus. This review highlights direct involvement of nuclear mTOR in regulating transcription factors, orchestrating epigenetic modifications, and facilitating chromatin remodeling. These effects intricately modulate gene expression programs associated with growth and metabolic processes. Furthermore, the review underscores the importance of nuclear mTOR in mediating the interplay between metabolism and epigenetic modifications. By integrating its functions in nutrient signaling and gene expression related to growth and metabolism, nuclear mTOR emerges as a central hub governing cellular homeostasis, malignant transformation, and cancer progression. Better understanding of nuclear mTOR signaling has the potential to lead to novel therapies against cancer and other growth-related diseases.
    Keywords:  ARID1A; androgen receptor; cBAF; cancer; chromatin; chromatin remodeling; epigenetics; growth; histone acetylation; histone methylation; mTOR; metabolism; nucleus; rapamycin; signaling; transcription
    DOI:  https://doi.org/10.3390/cells13090781
  23. Cell Mol Life Sci. 2024 May 06. 81(1): 209
    Physiological and pathological functions of TMEM106B in neurodegenerative diseases.
    Min Zhu, Guoxin Zhang, Lanxia Meng, Tingting Xiao, Xin Fang, Zhentao Zhang.
      As an integral lysosomal transmembrane protein, transmembrane protein 106B (TMEM106B) regulates several aspects of lysosomal function and is associated with neurodegenerative diseases. The TMEM106B gene mutations lead to lysosomal dysfunction and accelerate the pathological progression of Neurodegenerative diseases. Yet, the precise mechanism of TMEM106B in Neurodegenerative diseases remains unclear. Recently, different research teams discovered that TMEM106B is an amyloid protein and the C-terminal domain of TMEM106B forms amyloid fibrils in various Neurodegenerative diseases and normally elderly individuals. In this review, we discussed the physiological functions of TMEM106B. We also included TMEM106B gene mutations that cause neurodegenerative diseases. Finally, we summarized the identification and cryo-electronic microscopic structure of TMEM106B fibrils, and discussed the promising therapeutic strategies aimed at TMEM106B fibrils and the future directions for TMEM106B research in neurodegenerative diseases.
    Keywords:  Amyloid fibrils; Lysosome; Neurodegenerative diseases; Neurotherapy; Transmembrane protein 106B
    DOI:  https://doi.org/10.1007/s00018-024-05241-z
  24. Photodiagnosis Photodyn Ther. 2024 May 04. pii: S1572-1000(24)00234-5. [Epub ahead of print] 104196
    The effect of autophagy on hemoporfin-mediated photodynamic therapy in human umbilical vein endothelial cells.
    Minglan Shi, Meinian Xu, Xiaowen Huang, Changxing Li, Pingjiao Chen, Qian Li, Jia Guo, Menghua Zhu, Sijin He, Kang Zeng.
      SIGNIFICANCE: Hemoporfin-mediated photodynamic therapy (HMME-PDT) has been recognized as a safe and effective treatment for port wine stain (PWS). However, some patients show limited improvement even after multiple treatments. Herein, we aim to explore the effect of autophagy on HMME-PDT in human umbilical vein endothelial cells (HUVECs), so as to provide theoretical basis and treatment strategies to enhance clinical effectiveness.METHODS: Establish the in vitro HMME-PDT system by HUVECs. Apoptosis and necrosis were identified by Annexin Ⅴ-FITC/PI flow cytometry, and autophagy flux was detected by monitoring RFP-GFP-LC3 under the fluorescence microscope. Hydroxychloroquine and rapamycin were employed in the mechanism study. Specifically, the certain genes and proteins were qualified by qPCR and Western Blot, respectively. The cytotoxicity was measured by CCK8, VEGF-A secretion was determined by ELISA, and the tube formation of HUVECs was observed by angiogenesis assay.
    RESULTS: In vitro experiments revealed that autophagy and apoptosis coexisted in HUVECs treated by HMME-PDT. Apoptosis was dominant in early stage, while autophagy gradually increased in the middle and late stage. AMPK, AKT and mTOR participated in the regulation of autophagy induced by HMME-PDT, in which AMPK was positive regulation, while AKT and mTOR were negative regulation. Hydroxychloroquine could not inhibit HMME-PDT-induced autophagy, but capable of blocking the fusion of autophagosomes with lysosome. Rapamycin might cooperate with HMME-PDT to enhance autophagy in HUVECs, leading to increased cytotoxicity, reduced VEGF-A secretion, and weakened angiogenesis ability.
    CONCLUSIONS: Both autophagy and apoptosis contribute to HMME-PDT-induced HUVECs death. Pretreatment of HUVECs with rapamycin to induce autophagy might enhance the photodynamic killing effect of HMME-PDT on HUVECs. The combination of Rapamycin and HMME-PDT is expected to further improve the clinical efficacy.
    Keywords:  Apoptosis; Autophagy; Hemoporfin-mediated photodynamic therapy (HMME-PDT); Port-wine stain (PWS); human umbilical vein endothelial cells (HUVECs)
    DOI:  https://doi.org/10.1016/j.pdpdt.2024.104196
  25. Front Physiol. 2024 ;15 1352766
    In the fed state, autophagy plays a crucial role in assisting the insect vector Rhodnius prolixus mobilize TAG reserves under forced flight activity.
    Samara Santos-Araujo, Fabio Gomes, Luiz Fernando Carvalho-Kelly, José Roberto Meyer-Fernandes, Katia C Gondim, Isabela Ramos.
      Autophagy is a cellular degradation pathway mediated by highly conserved autophagy-related genes (Atgs). In our previous work, we showed that inhibiting autophagy under starvation conditions leads to significant physiological changes in the insect vector of Chagas disease Rhodnius prolixus; these changes include triacylglycerol (TAG) retention in the fat body, reduced survival and impaired locomotion and flight capabilities. Herein, because it is known that autophagy can be modulated in response to various stimuli, we further investigated the role of autophagy in the fed state, following blood feeding. Interestingly, the primary indicator for the presence of autophagosomes, the lipidated form of Atg8 (Atg8-II), displayed 20%-50% higher autophagic activation in the first 2 weeks after feeding compared to the third week when digestion was complete. Despite the elevated detection of autophagosomes, RNAi-mediated suppression of RpAtg6 and RpAtg8 did not cause substantial changes in TAG or protein levels in the fat body or the flight muscle during blood digestion. We also found that knockdown of RpAtg6 and RpAtg8 led to modest modulations in the gene expression of essential enzymes involved in lipid metabolism and did not significantly stimulate the expression of the chaperones BiP and PDI, which are the main effectors of the unfolded protein response. These findings indicate that impaired autophagy leads to slight disturbances in lipid metabolism and general cell proteostasis. However, the ability of insects to fly during forced flight until exhaustion was reduced by 60% after knockdown of RpAtg6 and RpAtg8. This change was accompanied by TAG and protein increases as well as decreased ATP levels in the fat body and flight muscle, indicating that autophagy during digestion, i.e., under fed conditions, is necessary to sustain high-performance activity.
    Keywords:  Chagas disease; Rhodnius prolixus; autophagy; flight activity; lipophagy
    DOI:  https://doi.org/10.3389/fphys.2024.1352766
  26. J Immunol. 2024 May 06. pii: ji2300826. [Epub ahead of print]
    IRF7 Exacerbates Candida albicans Infection by Compromising CD209-Mediated Phagocytosis and Autophagy-Mediated Killing in Macrophages.
    Furong Qing, Lina Sui, Wenji He, Yayun Chen, Li Xu, Liangmei He, Qiuxiang Xiao, Tianfu Guo, Zhiping Liu.
      IFN regulatory factor 7 (IRF7) exerts anti-infective effects by promoting the production of IFNs in various bacterial and viral infections, but its role in highly morbid and fatal Candida albicans infections is unknown. We unexpectedly found that Irf7 gene expression levels were significantly upregulated in tissues or cells after C. albicans infection in humans and mice and that IRF7 actually exacerbates C. albicans infection in mice independent of its classical function in inducing IFNs production. Compared to controls, Irf7-/- mice showed stronger phagocytosis of fungus, upregulation of C-type lectin receptor CD209 expression, and enhanced P53-AMPK-mTOR-mediated autophagic signaling in macrophages after C. albicans infection. The administration of the CD209-neutralizing Ab significantly hindered the phagocytosis of Irf7-/- mouse macrophages, whereas the inhibition of p53 or autophagy impaired the killing function of these macrophages. Thus, IRF7 exacerbates C. albicans infection by compromising the phagocytosis and killing capacity of macrophages via regulating CD209 expression and p53-AMPK-mTOR-mediated autophagy, respectively. This finding reveals a novel function of IRF7 independent of its canonical IFNs production and its unexpected role in enhancing fungal infections, thus providing more specific and effective targets for antifungal therapy.
    DOI:  https://doi.org/10.4049/jimmunol.2300826
  27. Autophagy. 2024 May 10.
    SCFFBXW5-mediated degradation of AQP3 suppresses autophagic cell death through the PDPK1-AKT-MTOR axis in hepatocellular carcinoma cells.
    Yupei Liang, Ping Chen, Shiwen Wang, Lili Cai, Feng Zhu, Yanyu Jiang, Lihui Li, Lihua Zhu, Yongqing Heng, Wenjuan Zhang, Yongfu Pan, Wenyi Wei, Lijun Jia.
      AQP3 (aquaporin 3 (Gill blood group)), a member of the AQP family, is an aquaglyceroporin which transports water, glycerol and small solutes across the plasma membrane. Beyond its role in fluid transport, AQP3 plays a significant role in regulating various aspects of tumor cell behavior, including cell proliferation, migration, and invasion. Nevertheless, the underlying regulatory mechanism of AQP3 in tumors remains unclear. Here, for the first time, we report that AQP3 is a direct target for ubiquitination by the SCFFBXW5 complex. In addition, we revealed that downregulation of FBXW5 significantly induced AQP3 expression to prompt macroautophagic/autophagic cell death in hepatocellular carcinoma (HCC) cells. Mechanistically, AQP3 accumulation induced by FBXW5 knockdown led to the degradation of PDPK1/PDK1 in a lysosomal-dependent manner, thus inactivating the AKT-MTOR pathway and inducing autophagic death in HCC. Taken together, our findings revealed a previously undiscovered regulatory mechanism through which FBXW5 degraded AQP3 to suppress autophagic cell death via the PDPK1-AKT-MTOR axis in HCC cells.
    Keywords:  AQP3; FBXW5; PDPK1-AKT-MTOR pathway; autophagic cell death; hepatocellular carcinoma
    DOI:  https://doi.org/10.1080/15548627.2024.2353497
  28. Cardiovasc Res. 2024 May 09. pii: cvae105. [Epub ahead of print]
    Role of endothelial Raptor in abnormal arteriogenesis after lower limb ischemia in type-2 diabetes.
    Ting Liu, Jiachen Zhang, Fangyuan Chang, Mengyu Sun, Jinlong He, Ding Ai.
      AIMS: Proper arteriogenesis after tissue ischemia is necessary to rebuild stable blood circulation; nevertheless, this process is impaired in type-2 diabetes mellitus (T2DM). Raptor, is a scaffold protein and a component of mammalian target of rapamycin complex 1 (mTORC1). However, the role of the endothelial Raptor in arteriogenesis under the conditions of T2DM remains unknown. This study investigated the role of endothelial Raptor in ischemia-induced arteriogenesis during T2DM.METHODS AND RESULTS: Although endothelial mTORC1 is hyperactive in T2DM, we observed a marked reduction in the expression of endothelial Raptor in two mouse models and in human vessels. Inducible endothelial-specific Raptor knockout severely exacerbated impaired hindlimb perfusion and arteriogenesis after hindlimb ischemic injury in 12-week high-fat diet fed mice. Additionally, we found that Raptor deficiency dampened vascular endothelial growth factor receptor 2 (VEGFR2) signaling in endothelial cells and inhibited VEGF-induced cell migration and tube formation in a PTP1B-dependent manner. Furthermore, mass spectrometry analysis indicated that Raptor interacts with neuropilin 1 (NRP1), the co-receptor of VEGFR2, and mediates VEGFR2 trafficking by facilitating the interaction between NRP1 and Synectin. Finally, we found that endothelial cell-specific overexpression of the Raptor mutant (loss of mTOR binding) reversed impaired hindlimb perfusion and arteriogenesis induced by endothelial Raptor knockout in high-fat diet fed mice.
    CONCLUSIONS: Collectively, our study demonstrated the crucial role of endothelial Raptor in promoting ischemia-induced arteriogenesis in T2DM by mediating VEGFR2 signaling. Thus, endothelial Raptor is a novel therapeutic target for promoting arteriogenesis and ameliorating perfusion in T2DM.
    Keywords:  Arteriogenesis; Endothelial cell; Raptor; T2DM; VEGF
    DOI:  https://doi.org/10.1093/cvr/cvae105
  29. Int J Cancer. 2024 May 08.
    Autophagy in glioblastoma: A mechanistic perspective.
    Durgesh Meena, Sushmita Jha.
      Glioblastoma (GBM) is one of the most lethal malignancies in humans. Even after surgical resection and aggressive radio- or chemotherapies, patients with GBM can survive for less than 14 months. Extreme inter-tumor and intra-tumor heterogeneity of GBM poses a challenge for resolving recalcitrant GBM pathophysiology. GBM tumor microenvironment (TME) exhibits diverse heterogeneity in cellular composition and processes contributing to tumor progression and therapeutic resistance. Autophagy is such a cellular process; that demonstrates a cell-specific and TME context-dependent role in GBM progression, leading to either the promotion or suppression of GBM progression. Autophagy can regulate GBM cell function directly via regulation of survival, migration, and invasion, or indirectly by affecting GBM TME composition such as immune cell population, tumor metabolism, and glioma stem cells. This review comprehensively investigates the role of autophagy in GBM pathophysiology.
    Keywords:  autophagy; glioblastoma; glioma stem cells; innate immunity; tumor metabolism; tumor microenvironment
    DOI:  https://doi.org/10.1002/ijc.34991
  30. iScience. 2024 May 17. 27(5): 109623
    ATG9B regulates bacterial internalization via actin rearrangement.
    Junpei Iibushi, Takashi Nozawa, Hirotaka Toh, Ichiro Nakagawa.
      Invasive bacterial pathogens are internalized by host cells through endocytosis, which is regulated by a cascade of actin rearrangement signals triggered by host cell receptors or bacterial proteins delivered into host cells. However, the molecular mechanisms that mediate actin rearrangement to promote bacterial invasion are not fully understood. Here, we show that the autophagy-related (ATG) protein ATG9B regulates the internalization of various bacteria by controlling actin rearrangement. ATG knockout screening and knockdown experiments in HeLa cells identified ATG9B as a critical factor for bacterial internalization. In particular, cells with ATG9B knockdown exhibited an accumulation of actin filaments and phosphorylated LIM kinase and cofilin, suggesting that ATG9B is involved in actin depolymerization. Furthermore, the kinase activity of Unc-51-like autophagy-activating kinase 1 was found to regulate ATG9B localization and actin remodeling. These findings revealed a newly discovered function of ATG proteins in bacterial infection rather than autophagy-mediated immunity.
    Keywords:  Cell biology; Microbiology
    DOI:  https://doi.org/10.1016/j.isci.2024.109623
  31. Int J Biol Sci. 2024 ;20(7): 2370-2387
    Dysfunction of STING Autophagy Degradation in Senescent Nucleus Pulposus Cells Accelerates Intervertebral Disc Degeneration.
    Zhiqian Chen, Chen Chen, Xiao Yang, Yifan Zhou, Xiankun Cao, Chen Han, Tangjun Zhou, Jie Zhao, An Qin.
      The pathogenesis of Intervertebral Disc Degeneration (IDD) is complex and multifactorial, with cellular senescence of nucleus pulposus (NP) cells and inflammation playing major roles in the progression of IDD. The stimulator of interferon genes (STING) axis is a key mediator of inflammation during infection, cellular stress, and tissue damage. Here, we present a progressive increase in STING in senescent NP cells with the degradation disorder. The STING degradation function in normal NP cells can prevent IDD. However, the dysfunction of STING degradation through autophagy causes the accumulation and high expression of STING in senescent NP cells as well as inflammation continuous activation together significantly promotes IDD. In senescent NP cells and intervertebral discs (IVDs), we found that STING autophagy degradation was significantly lower than that of normal NP cells and IVDs when STING was activated by 2'3'-cGAMP. Also, the above phenomenon was found in STINGgt/gt, cGAS-/- mice with models of age-induced, lumbar instability-induced IDD as well as found in the rat caudal IVD puncture models. Taken together, we suggested that the promotion of STING autophagy degradation in senescent NP Cells demonstrated a potential therapeutic modality for the treatment of IDD.
    Keywords:  Autophagy; Intervertebral Disc Degeneration; Nucleus Pulposus Cells; STING Degradation; Senescence.
    DOI:  https://doi.org/10.7150/ijbs.88534
  32. Genomics. 2024 May 02. pii: S0888-7543(24)00073-9. [Epub ahead of print] 110852
    Role of autophagy-related genes in liver cancer prognosis.
    Yuling Zhou, Rong Shan, Wangti Xie, Qiang Zhou, Qinghua Yin, Yuqi Su, Jia Xiao, Pan Luo, Xiang Yao, Jianlong Fang, Fang Wen, Erdong Shen, Jie Weng.
      Autophagy, a highly conserved process of protein and organelle degradation, has emerged as a critical regulator in various diseases, including cancer progression. In the context of liver cancer, the predictive value of autophagy-related genes remains ambiguous. Leveraging chip datasets from the TCGA and GTEx databases, we identified 23 differentially expressed autophagy-related genes in liver cancer. Notably, five key autophagy genes, PRKAA2, BIRC5, MAPT, IGF1, and SPNS1, were highlighted as potential prognostic markers, with MAPT showing significant overexpression in clinical samples. In vitro cellular assays further demonstrated that MAPT promotes liver cancer cell proliferation, migration, and invasion by inhibiting autophagy and suppressing apoptosis. Subsequent in vivo studies further corroborated the pro-tumorigenic role of MAPT by suppressing autophagy. Collectively, our model based on the five key genes provides a promising tool for predicting liver cancer prognosis, with MAPT emerging as a pivotal factor in tumor progression through autophagy modulation.
    Keywords:  Autophagy; Liver Cancer; MAPT; Prognostic markers; TCGA and GTEx databases; Tumor progression
    DOI:  https://doi.org/10.1016/j.ygeno.2024.110852
  33. bioRxiv. 2024 Apr 23. pii: 2023.06.25.546449. [Epub ahead of print]
    A mitochondrial surveillance mechanism activated by SRSF2 mutations in hematologic malignancies.
    Xiaolei Liu, Sudhish A Devadiga, Robert F Stanley, Ryan Morrow, Kevin Janssen, Mathieu Quesnel-Vallières, Oz Pomp, Adam A Moverley, Chenchen Li, Nicolas Skuli, Martin P Carroll, Jian Huang, Douglas C Wallace, Kristen W Lynch, Omar Abdel-Wahab, Peter S Klein.
      Splicing factor mutations are common in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML), but how they alter cellular functions is unclear. We show that the pathogenic SRSF2 P95H/+ mutation disrupts the splicing of mitochondrial mRNAs, impairs mitochondrial complex I function, and robustly increases mitophagy. We also identified a mitochondrial surveillance mechanism by which mitochondrial dysfunction modifies splicing of the mitophagy activator PINK1 to remove a poison intron, increasing the stability and abundance of PINK1 mRNA and protein. SRSF2 P95H -induced mitochondrial dysfunction increased PINK1 expression through this mechanism, which is essential for survival of SRSF2 P95H/+ cells. Inhibition of splicing with a glycogen synthase kinase 3 inhibitor promoted retention of the poison intron, impairing mitophagy and activating apoptosis in SRSF2 P95H/+ cells. These data reveal a homeostatic mechanism for sensing mitochondrial stress through PINK1 splicing and identify increased mitophagy as a disease marker and a therapeutic vulnerability in SRSF2 P95H mutant MDS and AML.
    DOI:  https://doi.org/10.1101/2023.06.25.546449
  34. Cell Biosci. 2024 May 04. 14(1): 57
    Impaired autophagy in myeloid cells aggravates psoriasis-like skin inflammation through the IL-1β/CXCL2/neutrophil axis.
    Jinju Lee, Mi-Yeon Kim, Hyo Jeong Kim, Woo Sun Choi, Hun Sik Kim.
      BACKGROUND: Psoriasis is an inflammatory skin disease characterized by the hyperproliferative epidermal keratinocytes and significant immune cells infiltration, leading to cytokines production such as IL-1β, TNF-α, IL-23, and IL-17. Recent study highlights the critical role of IL-1β in the induction and activation of pathogenic Th17 and IL-17-producing γδ T cells, contributing to psoriasis. However, the mechanism underlying IL-1β dysregulation in psoriasis pathogenesis is unclear. Autophagy regulates IL-1β production and has a pleiotropic effect on inflammatory disorders. Previous studies showed controversial role of autophagy in psoriasis pathogenesis, either pro-inflammatory in autophagy-deficient keratinocyte or anti-inflammatory in pharmacologically autophagy-promoting macrophages. Thus, the direct role of autophagy and its therapeutic potential in psoriasis remains unclear.METHODS: We used myeloid cell-specific autophagy-related gene 7 (Atg7)-deficient mice and determined the effect of autophagy deficiency in myeloid cells on neutrophilia and disease pathogenesis in an imiquimod-induced psoriasis mouse model. We then assessed the pathogenic mechanism focusing on immune cells producing IL-1β and IL-17 along with gene expression profiles associated with psoriasis in mouse model and public database on patients. Moreover, therapeutic potential of IL-1β blocking in such context was assessed.
    RESULTS: We found that autophagy deficiency in myeloid cells exacerbated neutrophilic inflammation and disease pathogenesis in mice with psoriasis. This autophagy-dependent effect was associated with a significant increase in IL-1β production from myeloid cells, particularly macrophages, Cxcl2 expression, and IL-17 A producing T cells including γδ T cells. Supporting this, treatment with systemic IL-1 receptor blocking antibody or topical saccharin, a disaccharide suppressing pro-IL-1β expression, led to the alleviation of neutrophilia and psoriatic skin inflammation linked to autophagy deficiency. The pathophysiological relevance of this finding was supported by dysregulation of autophagy-related genes and their correlation with Th17 cytokines in psoriatic skin lesion from patients with psoriasis.
    CONCLUSIONS: Our results suggest that autophagy dysfunction in myeloid cells, especially macrophages, along with IL-1β dysregulation has a causal role in neutrophilic inflammation and psoriasis pathogenesis.
    Keywords:  Autophagy; IL-17; IL-1β; Myeloid cells; Neutrophilic inflammation; Psoriasis
    DOI:  https://doi.org/10.1186/s13578-024-01238-0
  35. Front Mol Neurosci. 2024 ;17 1359294
    Rotenone-induced PINK1/Parkin-mediated mitophagy: establishing a silkworm model for Parkinson's disease potential.
    Hantao Zhang, Jinyue Yang, Yinglu Guo, Peng Lü, Xun Gong, Keping Chen, Xiubin Li, Min Tang.
      Parkinson's disease (PD), ranking as the second most prevalent neurodegenerative disorder globally, presents a pressing need for innovative animal models to deepen our understanding of its pathophysiology and explore potential therapeutic interventions. The development of such animal models plays a pivotal role in unraveling the complexities of PD and investigating promising treatment avenues. In this study, we employed transcriptome sequencing on BmN cells treated with 1 μg/ml rotenone, aiming to elucidate the underlying toxicological mechanisms. The investigation brought to light a significant reduction in mitochondrial membrane potential induced by rotenone, subsequently triggering mitophagy. Notably, the PTEN induced putative kinase 1 (PINK1)/Parkin pathway emerged as a key player in the cascade leading to rotenone-induced mitophagy. Furthermore, our exploration extended to silkworms exposed to 50 μg/ml rotenone, revealing distinctive motor dysfunction as well as inhibition of Tyrosine hydroxylase (TH) gene expression. These observed effects not only contribute valuable insights into the impact and intricate mechanisms of rotenone exposure on mitophagy but also provide robust scientific evidence supporting the utilization of rotenone in establishing a PD model in the silkworm. This comprehensive investigation not only enriches our understanding of the toxicological pathways triggered by rotenone but also highlights the potential of silkworms as a valuable model organism for PD research.
    Keywords:  Parkinson’s disease; animal model; mitophagy; rotenone; silkworm
    DOI:  https://doi.org/10.3389/fnmol.2024.1359294
  36. Autophagy. 2024 May 10.
    Structural and functional characterization of the role of acetylation on the interactions of the human Atg8-family proteins with the autophagy receptor TP53INP2/DOR.
    Mohamed G Ali, Haytham M Wahba, Sebastian Igelmann, Normand Cyr, Gerardo Ferbeyre, James G Omichinski.
      The Atg8-family proteins (MAP1LC3/LC3A, LC3B, LC3C, GABARAP, GABARAPL1 and GABARAPL2) play a pivotal role in macroautophagy/autophagy through their ability to help form autophagosomes. Although autophagosomes form in the cytoplasm, nuclear levels of the Atg8-family proteins are significant. Recently, the nuclear/cytoplasmic shuttling of LC3B was shown to require deacetylation of two Lys residues (K49 and K51 in LC3B), which are conserved in Atg8-family proteins. To exit the nucleus, deacetylated LC3B must bind TP53INP2/TP53INP2 (tumor protein p53 inducible nuclear protein 2) through interaction with the LC3-interacting region (LIR) of TP53INP2 (TP53INP2LIR). To examine their selectivity for TP53INP2 and the role of the conserved Lys residues in Atg8-family proteins, we prepared the six human Atg8-family proteins and acetylated variants of LC3A and GABARAP for biophysical and structural characterization of their interactions with the TP53INP2LIR. Isothermal titration calorimetry (ITC) experiments demonstrate that this LIR binds preferentially to GABARAP subfamily proteins, and that only acetylation of the second Lys residue reduces binding to GABARAP and LC3A. Crystal structures of complexes with GABARAP and LC3A (acetylated and deacetylated) define a β-sheet in the TP53INP2LIR that determines the GABARAP selectivity and establishes the importance of acetylation at the second Lys. The in vitro results were confirmed in cells using acetyl-mimetic variants of GABARAP and LC3A to examine nuclear/cytoplasmic shuttling and colocalization with TP53INP2. Together, the results demonstrate that TP53INP2 shows selectivity to the GABARAP subfamily and acetylation at the second Lys of GABARAP and LC3A disrupts key interactions with TP53INP2 required for their nuclear/cytoplasmic shuttling.
    Keywords:  GABARAP; LC3-interacting region (LIR); MAP1LC3A/LC3A; X-ray crystallography; nuclear/cytoplasmic shuttling sirtuin 1 (SIRT1)
    DOI:  https://doi.org/10.1080/15548627.2024.2353443
  37. Epilepsia. 2024 May 08.
    Pathogenic MTOR somatic variant causing focal cortical dysplasia drives hyperexcitability via overactivation of neuronal GluN2C N-methyl-D-aspartate receptors.
    Louison Pineau, Emmanuelle Buhler, Sarah Tarhini, Sylvian Bauer, Valérie Crepel, Françoise Watrin, Carlos Cardoso, Alfonso Represa, Pierre Szepetowski, Nail Burnashev.
      OBJECTIVE: Genetic variations in proteins of the mechanistic target of rapamycin (mTOR) pathway cause a spectrum of neurodevelopmental disorders often associated with brain malformations and with intractable epilepsy. The mTORopathies are characterized by hyperactive mTOR pathway and comprise tuberous sclerosis complex (TSC) and focal cortical dysplasia (FCD) type II. How hyperactive mTOR translates into abnormal neuronal activity and hypersynchronous network remains to be better understood. Previously, the role of upregulated GluN2C-containing glutamate-gated N-methyl-D-aspartate receptors (NMDARs) has been demonstrated for germline defects in the TSC genes. Here, we questioned whether this mechanism would expand to other mTORopathies in the different context of a somatic genetic variation of the MTOR protein recurrently found in FCD type II.METHODS: We used a rat model of FCD created by in utero electroporation of neural progenitors of dorsal telencephalon with expression vectors encoding either the wild-type or the pathogenic MTOR variant (p.S2215F). In this mosaic configuration, patch-clamp whole-cell recordings of the electroporated, spiny stellate neurons and extracellular recordings of the electroporated areas were performed in neocortical slices. Selective inhibitors were used to target mTOR activity and GluN2C-mediated currents.
    RESULTS: Neurons expressing the mutant protein displayed an excessive activation of GluN2C NMDAR-mediated spontaneous excitatory postsynaptic currents. GluN2C-dependent increase in spontaneous spiking activity was detected in the area of electroporated neurons in the mutant condition and was restricted to a critical time window between postnatal days P9 and P20.
    SIGNIFICANCE: Somatic MTOR pathogenic variant recurrently found in FCD type II resulted in overactivation of GluN2C-mediated neuronal NMDARs in neocortices of rat pups. The related and time-restricted local hyperexcitability was sensitive to subunit GluN2C-specific blockade. Our study suggests that GluN2C-related pathomechanisms might be shared in common by mTOR-related brain disorders.
    Keywords:  FCD; NMDAR; mTORopathies; neuron
    DOI:  https://doi.org/10.1111/epi.18000
  38. Sci Rep. 2024 05 07. 14(1): 10507
    YANK2 activated by Fyn promotes glioma tumorigenesis via the mTOR-independent p70S6K activation pathway.
    Yue Shi, Yue Cheng, Wei Wang, Liu Tang, Wensheng Li, Liyuan Zhang, Zheng Yuan, Feng Zhu, Qiuhong Duan.
      Glioma, particularly glioblastomas (GBM), is incurable brain tumor. The most targeted receptor tyrosine kinase (RTKs) drugs did not bring benefit to GBM patients. The mechanism of glioma growth continues to be explored to find more effective treatment. Here, we reported that Ser/Thr protein kinase YANK2 (yet another kinase 2) is upregulated in glioma tissues and promotes the growth and proliferation of glioma in vitro and in vivo. Further, we confirmed that oncogene Fyn directly activated YANK2 through phosphorylation its Y110, and Fyn-mediated YANK2 phosphorylation at Y110 site promotes glioma growth by increasing its stability. Finally, YANK2 was proved to be a novel upstream kinase of p70S6K and promotes glioma growth by directly phosphorylating p70S6K at T389. Taken together, we found a new mTOR-independent p70S6K activation pathway, Fyn-YANK2-p70S6K, which promotes glioma growth, and YANK2 is a potential oncogene and serves as a novel therapeutic target for glioma.
    Keywords:  Fyn; Glioma; Tumorigenesis; YANK2; p70S6K
    DOI:  https://doi.org/10.1038/s41598-024-61157-5
  39. Neurobiol Dis. 2024 May 03. pii: S0969-9961(24)00121-9. [Epub ahead of print]196 106522
    LRRK2 kinase inhibition protects against Parkinson's disease-associated environmental toxicants.
    Neda M Ilieva, Eric K Hoffman, Mohammed A Ghalib, J Timothy Greenamyre, Briana R De Miranda.
      Idiopathic Parkinson's disease (PD) is epidemiologically linked with exposure to toxicants such as pesticides and solvents, which comprise a wide array of chemicals that pollute our environment. While most are structurally distinct, a common cellular target for their toxicity is mitochondrial dysfunction, a key pathological trigger involved in the selective vulnerability of dopaminergic neurons. We and others have shown that environmental mitochondrial toxicants such as the pesticides rotenone and paraquat, and the organic solvent trichloroethylene (TCE) appear to be influenced by the protein LRRK2, a genetic risk factor for PD. As LRRK2 mediates vesicular trafficking and influences endolysosomal function, we postulated that LRRK2 kinase activity may inhibit the autophagic removal of toxicant damaged mitochondria, resulting in elevated oxidative stress. Conversely, we suspected that inhibition of LRRK2, which has been shown to be protective against dopaminergic neurodegeneration caused by mitochondrial toxicants, would reduce the intracellular production of reactive oxygen species (ROS) and prevent mitochondrial toxicity from inducing cell death. To do this, we tested in vitro if genetic or pharmacologic inhibition of LRRK2 (MLi2) protected against ROS caused by four toxicants associated with PD risk - rotenone, paraquat, TCE, and tetrachloroethylene (PERC). In parallel, we assessed if LRRK2 inhibition with MLi2 could protect against TCE-induced toxicity in vivo, in a follow up study from our observation that TCE elevated LRRK2 kinase activity in the nigrostriatal tract of rats prior to dopaminergic neurodegeneration. We found that LRRK2 inhibition blocked toxicant-induced ROS and promoted mitophagy in vitro, and protected against dopaminergic neurodegeneration, neuroinflammation, and mitochondrial damage caused by TCE in vivo. We also found that cells with the LRRK2 G2019S mutation displayed exacerbated levels of toxicant induced ROS, but this was ameliorated by LRRK2 inhibition with MLi2. Collectively, these data support a role for LRRK2 in toxicant-induced mitochondrial dysfunction linked to PD risk through oxidative stress and the autophagic removal of damaged mitochondria.
    Keywords:  Environmental toxicants; Gene x environment (GxE); Leucine rich repeat kinase 2 (LRRK2); Mitochondria; Parkinson's disease (PD)
    DOI:  https://doi.org/10.1016/j.nbd.2024.106522
  40. Adv Sci (Weinh). 2024 May 09. e2401327
    Supramolecular Nanofibers Ameliorate Bleomycin-Induced Pulmonary Fibrosis by Restoring Autophagy.
    Debin Zheng, Jiasen Guo, Ziyi Liang, Yueyue Jin, Yinghao Ding, Jingfei Liu, Chao Qi, Kaiwen Shi, Limin Xie, Meiqi Zhu, Ling Wang, Zhiwen Hu, Zhimou Yang, Qian Liu, Xiaoxue Li, Wen Ning, Jie Gao.
      Idiopathic pulmonary fibrosis (IPF) is a progressive and ultimately fatal interstitial lung disease, with limited therapeutic options available. Impaired autophagy resulting from aberrant TRB3/p62 protein-protein interactions (PPIs) contributes to the progression of IPF. Restoration of autophagy by modulating the TRB3/p62 PPIs has rarely been reported for the treatment of IPF. Herein, peptide nanofibers are developed that specifically bind to TRB3 protein and explored their potential as a therapeutic approach for IPF. By conjugating with the self-assembling fragment (Ac-GFFY), a TRB3-binding peptide motif A2 allows for the formation of nanofibers with a stable α-helix secondary structure. The resulting peptide (Ac-GFFY-A2) nanofibers exhibit specific high-affinity binding to TRB3 protein in saline buffer and better capacity of cellular uptake to A2 peptide. Furthermore, the TRB3-targeting peptide nanofibers efficiently interfere with the aberrant TRB3/p62 PPIs in activated fibroblasts and fibrotic lung tissue of mice, thereby restoring autophagy dysfunction. The TRB3-targeting peptide nanofibers inhibit myofibroblast differentiation, collagen production, and fibroblast migration in vitro is demonstrated, as well as bleomycin-induced pulmonary fibrosis in vivo. This study provides a supramolecular method to modulate PPIs and highlights a promising strategy for treating IPF diseases by restoring autophagy.
    Keywords:  autophagy; peptide nanofiber; protein‐protein interactions; pulmonary fibrosis; self‐assembly
    DOI:  https://doi.org/10.1002/advs.202401327
  41. Clin Hemorheol Microcirc. 2024 May 10.
    PCSK9 induces endothelial cell autophagy by regulating the PI3K/ATK pathway in atherosclerotic coronary heart disease.
    Wei-Wei Li, Ze-Ming Guo, Bing-Cai Wang, Qing-Quan Liu, Wen-An Zhao, Xiao-Lan Wei.
      OBJECTIVE: Atherosclerosis is a chronic inflammatory disease of the arteries, and its pathogenesis is related to endothelial dysfunction. It has been found that the protein convertase subtilin/kexin9 type (PCSK9) plays an important role in AS, but its specific mechanism is still unclear.METHODS: In this study, we first cultured human umbilical vein endothelial cells (HUVECs) with 50 or 100μg/ml oxidized low-density lipoprotein (ox-LDL) for 24 hours to establish a coronary atherosclerosis cell model.
    RESULTS: The results showed that ox-LDL induced HUVEC injury and autophagy and upregulated PCSK9 protein expression in HUVECs in a concentration-dependent manner. Silencing PCSK9 expression with siRNA inhibited ox-LDL-induced HUVEC endothelial dysfunction, inhibited the release of inflammatory factors, promoted HUVEC proliferation and inhibited apoptosis. In addition, ox-LDL increased the expression of LC3B-I and LC3B-II and decreased the expression of p62. However, these processes are reversed by sh-PCSK9. In addition, sh-PCSK9 can inhibit PI3K, AKT and mTOR phosphorylation and promote autophagy.
    CONCLUSION: Taken together, our research shows that silencing PCSK9 inhibits the PI3K/ATK/mTOR pathway to activate ox-LDL-induced autophagy in vascular endothelial cells, alleviating endothelial cell injury and inflammation.
    Keywords:  PCSK9; PI3K; atherosclerotic coronary; autophagy; endothelial cell
    DOI:  https://doi.org/10.3233/CH-242172
  42. FEBS J. 2024 May 06.
    A new mutation in the Parkinson's-related FBXO7 gene impairs mitochondrial and proteasomal function.
    Elisa Navarro, Noemí Esteras.
      Around 10% of Parkinson's disease (PD) cases are associated with mutations in various genes, including FBXO7, which encodes the substrate-recognition component for the Skp1-Cullin-F-box (SCF) class of ubiquitin E3 ligases that target proteins for proteasomal degradation. In their recent study, Al Rawi et al. characterized a new mutation in FBXO7, L250P, in a pediatric patient. Their findings reveal that the L250P mutation abolishes Fbxo7 interaction with the proteasome regulator, proteasome inhibitor 31kD (PI31), affecting proteasomal activity and the ubiquitination of some of the ligase's targets. Furthermore, the authors show that this previously undescribed mutation impairs mitochondrial function and mitophagy, emphasizing the importance of mitochondrial and proteasomal dysfunction in PD pathogenesis.
    Keywords:  Fbxo7/PARK15; PI31/PSMF1; Parkinson; mitochondria; proteasome
    DOI:  https://doi.org/10.1111/febs.17155
  43. Mol Pharm. 2024 May 09.
    Saponin and Ribosome-Inactivating Protein Synergistically Trigger Lysosome-Dependent Apoptosis by Inhibiting Lysophagy: Potential to Become a New Antitumor Strategy.
    Piao Chen, Xue-Wei Cao, Jing-Wen Dong, Jian Zhao, Fu-Jun Wang.
      The susceptibility of lysosomal membranes in tumor cells to cationic amphiphilic drugs (CADs) enables CADs to induce lysosomal membrane permeabilization (LMP) and trigger lysosome-dependent cell death (LDCD), suggesting a potential antitumor therapeutic approach. However, the existence of intrinsic lysosomal damage response mechanisms limits the display of the pharmacological activity of CADs. In this study, we report that low concentrations of QS-21, a saponin with cationic amphiphilicity extracted from Quillaja Saponaria tree, can induce LMP but has nontoxicity to tumor cells. QS-21 and MAP30, a type I ribosome-inactivating protein, synergistically induce apoptosis in tumor cells at low concentrations of both. Mechanistically, QS-21-induced LMP helps MAP30 escape from endosomes or lysosomes and subsequently enter the endoplasmic reticulum, where MAP30 downregulates the expression of autophagy-associated LC3 proteins, thereby inhibiting lysophagy. The inhibition of lysophagy results in the impaired clearance of damaged lysosomes, leading to the leakage of massive lysosomal contents such as cathepsins into the cytoplasm, ultimately triggering LDCD. In summary, our study showed that coadministration of QS-21 and MAP30 amplified the lysosomal disruption and can be a new synergistic LDCD-based antitumor therapy.
    Keywords:  lysophagy; lysosomal membrane permeabilization; lysosome-dependent cell death; ribosome-inactivating protein; saponin
    DOI:  https://doi.org/10.1021/acs.molpharmaceut.4c00140
  44. Cell Commun Signal. 2024 May 06. 22(1): 258
    NCX1/Ca2+ promotes autophagy and decreases bortezomib activity in multiple myeloma through non-canonical NFκB signaling pathway.
    Tingting Li, Pingping Xiao, Dongbiao Qiu, Apeng Yang, Qingjiao Chen, Junfang Lin, Yao Liu, Junmin Chen, Zhiyong Zeng.
      Although bortezomib (BTZ) is the cornerstone of anti-multiple myeloma (MM) therapy, the inevitable primary and secondary drug resistance still seriously affects the prognosis of patients. New treatment strategies are in need. Sodium-calcium exchanger 1 (NCX1) is a calcium-permeable ion transporter on the membrane, and our previous studies showed that low NCX1 confers inferior viability in MM cells and suppressed osteoclast differentiation. However, the effect of NCX1 on BTZ sensitivity of MM and its possible mechanism remain unclear. In this study, we investigated the effect of NCX1 on BTZ sensitivity in MM, focusing on cellular processes of autophagy and cell viability. Our results provide evidence that NCX1 expression correlates with MM disease progression and low NCX1 expression increases BTZ sensitivity. NCX1/Ca2+ triggered autophagic flux through non-canonical NFκB pathway in MM cells, leading to attenuated the sensitivity of BTZ. Knockdown or inhibition of NCX1 could potentiate the anti-MM activity of BTZ in vitro and vivo, and inhibition of autophagy sensitized NCX1-overexpressing MM cells to BTZ. In general, this work implicates NCX1 as a potential therapeutic target in MM with BTZ resistance and provides novel mechanistic insights into its vital role in combating BTZ resistance.
    Keywords:  Autophagy; Bortezomib; Calcium; NFκB; Sodium-calcium exchanger 1
    DOI:  https://doi.org/10.1186/s12964-024-01628-4
  45. Heliyon. 2024 May 15. 10(9): e30475
    Synergistic induction of autophagy in gastric cancer by targeting CDK4/6 and MEK through AMPK/mTOR pathway.
    Hong Zhou, Guiling Li, Liuyue Kan, Mingyu Yang, Yu Liu, Xiaye Miu, Lei Shi, Zhanjun Yang, Xucai Zheng, Hui Chen, Chuanli Ren.
      KRAS is a commonly mutated oncogene in human gastric cancer and is often associated with drug resistance and poor prognosis. Co-clinical trial of combined MEK-CDK4/6 inhibition in KRAS mutated cancers demonstrated therapeutic efficacy in patient-derived xenografts and safety in patients. Here, present research focuses on targeting CDK4/6 and MEK synergistically block the proliferation of KRAS-mutated gastric cancer cells in vitro and in vivo and induced autophagy through the AMPK/mTOR pathway. Furthermore, autophagy inhibitor combined with targeting CDK4/6 and MEK therapy had significant antitumor effects on KRAS mutant gastric cancer cells. Clinical trials are needed to determine the mechanism behind this finding and its clinical utility. In conclusion, our results demonstrate autophagy inhibitor combined targeting MEK and CDK4/6 that concurrently block multiple metabolic processes may be an effective therapeutic approach for gastric cancer.
    Keywords:  AMPK/mTOR; CDK4/6; Gastric cancer; KRAS; MEK
    DOI:  https://doi.org/10.1016/j.heliyon.2024.e30475
  46. Int J Ophthalmol. 2024 ;17(3): 420-434
    Overexpression of TRPV1 activates autophagy in human lens epithelial cells under hyperosmotic stress through Ca2+-dependent AMPK/mTOR pathway.
    Liu-Hui Huang, Jiao Lyu, Sheng Chen, Ting-Yi Liang, Yu-Qing Rao, Ping Fei, Jing Li, Hai-Ying Jin, Pei-Quan Zhao.
      AIM: To explore whether autophagy functions as a cellular adaptation mechanism in lens epithelial cells (LECs) under hyperosmotic stress.METHODS: LECs were treated with hyperosmotic stress at the concentration of 270, 300, 400, 500, or 600 mOsm for 6, 12, 18, 24h in vitro. Polymerase chain reaction (PCR) was employed for the mRNA expression of autophagy-related genes, while Western blotting detected the targeted protein expression. The transfection of stub-RFP-sens-GFP-LC3 autophagy-related double fluorescence lentivirus was conducted to detect the level of autophagy flux. Scanning electron microscopy was used to detect the existence of autolysosome. Short interfering RNA of autophagy-related gene (ATG) 7, transient receptor potential vanilloid (TRPV) 1 overexpression plasmid, related agonists and inhibitors were employed to their influence on autophagy related pathway. Flow cytometry was employed to test the apoptosis and intracellular Ca2+ level. Mitochondrial membrane potential was measured by JC-1 staining. The cell counting kit-8 assay was used to calculate the cellular viability. The wound healing assay was used to evaluate the wound closure rate. GraphPad 6.0 software was utilized to evaluate the data.
    RESULTS: The hyperosmotic stress activated autophagy in a pressure- and time-dependent manner in LECs. Beclin 1 protein expression and conversion of LC3B II to LC3B I increased, whereas sequestosome-1 (SQSTM1) protein expression decreased. Transient Ca2+ influx was stimulated caused by hyperosmotic stress, levels of mammalian target of rapamycin (mTOR) phosphorylation decreased, and the level of AMP-activated protein kinase (AMPK) phosphorylation increased in the early stage. Based on this evidence, autophagy activation through the Ca2+-dependent AMPK/mTOR pathway might represent an adaptation process in LECs under hyperosmotic stress. Hyperosmotic stress decreased cellular viability and accelerated apoptosis in LECs and cellular migration decreased. Inhibition of autophagy by ATG7 knockdown had similar results. TRPV1 overexpression increased autophagy and might be crucial in the occurrence of autophagy promoted by hyperosmotic stress.
    CONCLUSION: A combination of hyperosmotic stress and autophagy inhibition may be a promising approach to decrease the number of LECs in the capsular bag and pave the way for improving prevention of posterior capsular opacification and capsular fibrosis.
    Keywords:  apoptosis; autophagy; cataract; hyperosmotic stress; lens epithelial cell; posterior capsular opacification; transient receptor potential vanilloid 1
    DOI:  https://doi.org/10.18240/ijo.2024.03.03
  47. Physiol Res. 2024 Apr 30. 73(2): 253-263
    PINK1/Park2-Mediated Mitophagy Relieve Non-Alcoholic Fatty Liver Disease.
    H He, Y Tang, L Zhuang, Y Zheng, X Huang.
      Up to now, there's a limited number of studies on the relationship between PINK1/Park2 pathway and mitophagy in NAFLD. To investigate the effect of Park2-mediated mitophagy on non-alcoholic fatty liver disease (NAFLD). Oleic acid was used for the establishment of NAFLD model. Oil red-dyed lipid drops and mitochondrial alternations were observed by transmission electron microscopy. Enzymatic kit was used to test lipid content. The levels of IL-8 and TNF-alpha were determined by ELISA. Lenti-Park2 and Park2-siRNA were designed to upregulate and downregulate Park2 expression, respectively. The changing expression of PINK and Park2 was detected by RT-qPCR and Western blot. Immunofluorescence staining was applied to measure the amount of LC3. Successful NAFLD modeling was featured by enhanced lipid accumulation, as well as the elevated total cholesterol (TC), triglyceride (TG), TNF-alpha and IL-8 levels. Mitochondria in NAFLD model were morphologically and functionally damaged. Park2 expression was upregulated by lenti-Park2 and downregulated through Park2-siRNA. The PINK1 expression showed the same trend as Park2 expression. Immunofluorescence staining demonstrated that the when Park2 was overexpressed, more LC3 protein on mitochondrial autophagosome membrane was detected, whereas Park2 knockdown impeded LC3' locating on the membrane. The transmission electron microscopy image exhibited that the extent of damage to the mitochondrial in NAFLD model was revered by enhanced Park2 expression but further exacerbated by reduced Park2 expression. Park2-mediated mitophagy could relive NAFLD and may be a novel therapeutic target for NAFLD treatment. Keywords: Non-alcoholic Fatty Liver Disease (NAFLD), Mitophagy, PINK1/Park2, Park2, PINK1.
  48. Cell Mol Life Sci. 2024 May 06. 81(1): 207
    Initiation of acute pancreatitis in mice is independent of fusion between lysosomes and zymogen granules.
    Lukas Zierke, Daniel John, Marcel Gischke, Quang Trung Tran, Matthias Sendler, Frank Ulrich Weiss, Uwe T Bornscheuer, Christoph Ritter, Markus M Lerch, Ali A Aghdassi.
      The co-localization of the lysosomal protease cathepsin B (CTSB) and the digestive zymogen trypsinogen is a prerequisite for the initiation of acute pancreatitis. However, the exact molecular mechanisms of co-localization are not fully understood. In this study, we investigated the role of lysosomes in the onset of acute pancreatitis by using two different experimental approaches. Using an acinar cell-specific genetic deletion of the ras-related protein Rab7, important for intracellular vesicle trafficking and fusion, we analyzed the subcellular distribution of lysosomal enzymes and the severity of pancreatitis in vivo and ex vivo. Lysosomal permeabilization was performed by the lysosomotropic agent Glycyl-L-phenylalanine 2-naphthylamide (GPN). Acinar cell-specific deletion of Rab7 increased endogenous CTSB activity and despite the lack of re-distribution of CTSB from lysosomes to the secretory vesicles, the activation of CTSB localized in the zymogen compartment still took place leading to trypsinogen activation and pancreatic injury. Disease severity was comparable to controls during the early phase but more severe at later time points. Similarly, GPN did not prevent CTSB activation inside the secretory compartment upon caerulein stimulation, while lysosomal CTSB shifted to the cytosol. Intracellular trypsinogen activation was maintained leading to acute pancreatitis similar to controls. Our results indicate that initiation of acute pancreatitis seems to be independent of the presence of lysosomes and that fusion of lysosomes and zymogen granules is dispensable for the disease onset. Intact lysosomes rather appear to have protective effects at later disease stages.
    Keywords:  Acute pancreatitis; Cathepsin B; Co-localization; Lysosome; Secretory vesicle; Trypsinogen
    DOI:  https://doi.org/10.1007/s00018-024-05247-7
  49. Exp Cell Res. 2024 May 08. pii: S0014-4827(24)00162-9. [Epub ahead of print] 114071
    Low shear stress-induced blockage of autophagic flux impairs endothelial barrier and facilitates atherosclerosis in mice.
    Ruhao Cao, Ruxian Sun, Yuanzhi Ye, Pingge Tian, Bin Huang, Haowen Ye, Libing Dai, Zirong Lan, Jia Liu, Li Li.
      Atherosclerosis preferentially occurs in areas with low shear stress (LSS) and oscillatory flow. LSS has been demonstrated to correlate with the development of atherosclerosis. The sphingosine 1-phosphate receptor 1 (S1PR1), involving intravascular blood flow sensing, regulates vascular development and vascular barrier function. However, whether LSS affects atherosclerosis via regulating S1PR1 remains incompletely clear. In this study, immunostaining results of F-actin, β-catenin, and VE-cadherin indicated that LSS impaired endothelial barrier function in human umbilical vein endothelial cells (HUVECs). Western blot analysis showed that LSS resulted in blockage of autophagic flux in HUVECs. In addition, autophagy agonist Rapamycin (Rapa) antagonized LSS-induced endothelial barrier dysfunction, whereas autophagic flux inhibitor Bafilomycin A1 (BafA1) exacerbated it, indicating that LSS promoted endothelial barrier dysfunction by triggering autophagic flux blockage. Notably, gene expression analysis revealed that LSS downregulated S1PR1 expression, which was antagonized by Rapa. Selective S1PR1 antagonist W146 impaired endothelial barrier function of HUVECs under high shear stress (HSS) conditions. Moreover, our data showed that expression of GAPARAPL2, a member of autophagy-related gene 8 (Atg8) proteins, was decreased in HUVECs under LSS conditions. Autophagic flux blockage induced by GAPARAPL2 knockdown inhibited S1PR1, aggravated endothelial barrier dysfunction of HUVECs in vitro, and promoted aortic atherosclerosis in ApoE-/- mice in vivo. Our study demonstrates that autophagic flux blockage induced by LSS downregulates S1PR1 expression and impairs endothelial barrier function. GABARAPL2 inhibition is involved in LSS-induced autophagic flux blockage, which impairs endothelial barrier function via downregulation of S1PR1.
    Keywords:  GAPARAPL2; S1PR1; atherosclerosis; autophagy; endothelial barrier function; shear stress
    DOI:  https://doi.org/10.1016/j.yexcr.2024.114071
  50. J Alzheimers Dis. 2024 May 10.
    In-silico Codon Context and Synonymous Usage Analysis of Genes for Molecular Mechanisms Inducing Autophagy and Apoptosis with Reference to Neurodegenerative Disorders.
    Rekha Khandia, Pankaj Gurjar, Victoria Romashchenko, Sami A Al-Hussain, Athanasios Alexiou, George Zouganelis, Magdi E A Zaki.
      Background: Autophagy and apoptosis are cellular processes that maintain cellular homeostasis and remove damaged or aged organelles or aggregated and misfolded proteins. Stress factors initiate the signaling pathways common to autophagy and apoptosis. An imbalance in the autophagy and apoptosis, led by cascade of molecular mechanism prior to both processes culminate into neurodegeneration.Objective: In present study, we urge to investigate the codon usage pattern of genes which are common before initiating autophagy and apoptosis.
    Methods: In the present study, we took up eleven genes (DAPK1, BECN1, PIK3C3 (VPS34), BCL2, MAPK8, BNIP3 L (NIX), PMAIP1, BAD, BID, BBC3, MCL1) that are part of molecular signaling mechanism prior to autophagy and apoptosis. We analyzed dinucleotide odds ratio, codon bias, usage, context, and rare codon analysis.
    Results: CpC and GpG dinucleotides were abundant, with the dominance of G/C ending codons as preferred codons. Clustering analysis revealed that MAPK8 had a distinct codon usage pattern compared to other envisaged genes. Both positive and negative contexts were observed, and GAG-GAG followed by CTG-GCC was the most abundant codon pair. Of the six synonymous arginine codons, two codons CGT and CGA were the rarest.
    Conclusions: The information presented in the study may be used to manipulate the process of autophagy and apoptosis and to check the pathophysiology associated with their dysregulation.
    Keywords:  Alzheimer’s disease; apoptosis; autophagy; codon context; codon pairs; rare codons; relative synonymous codon usage
    DOI:  https://doi.org/10.3233/JAD-240158
  51. Cells. 2024 Apr 24. pii: 737. [Epub ahead of print]13(9):
    The Suppression of Ubiquitin C-Terminal Hydrolase L1 Promotes the Transdifferentiation of Auditory Supporting Cells into Hair Cells by Regulating the mTOR Pathway.
    Yeon Ju Kim, In Hye Jeong, Jung Ho Ha, Young Sun Kim, Siung Sung, Jeong Hun Jang, Yun-Hoon Choung.
      In mammals, hearing loss is irreversible due to the lack of the regenerative capacity of the auditory epithelium. However, stem/progenitor cells in mammalian cochleae may be a therapeutic target for hearing regeneration. The ubiquitin proteasome system plays an important role in cochlear development and maintenance. In this study, we investigated the role of ubiquitin C-terminal hydrolase L1 (UCHL1) in the process of the transdifferentiation of auditory supporting cells (SCs) into hair cells (HCs). The expression of UCHL1 gradually decreased as HCs developed and was restricted to inner pillar cells and third-row Deiters' cells between P2 and P7, suggesting that UCHL1-expressing cells are similar to the cells with Lgr5-positive progenitors. UCHL1 expression was decreased even under conditions in which supernumerary HCs were generated with a γ-secretase inhibitor and Wnt agonist. Moreover, the inhibition of UCHL1 by LDN-57444 led to an increase in HC numbers. Mechanistically, LDN-57444 increased mTOR complex 1 activity and allowed SCs to transdifferentiate into HCs. The suppression of UCHL1 induces the transdifferentiation of auditory SCs and progenitors into HCs by regulating the mTOR pathway.
    Keywords:  UCHL1; auditory hair cells; mTOR pathway; supporting cells; transdifferentiation
    DOI:  https://doi.org/10.3390/cells13090737
  52. Acta Biomater. 2024 May 08. pii: S1742-7061(24)00249-6. [Epub ahead of print]
    Modulating Synovial Macrophage Pyroptosis and Mitophagy Interactions to Mitigate Osteoarthritis Progression using Functionalized Nanoparticles.
    Weizhong Qi, Li Jin, Shiqian Huang, Alafate Aikebaier, Song Xue, QianYi Wang, Qiyue Chen, Yao Lu, Changhai Ding.
      Synovial macrophages play an important role in the progression of osteoarthritis (OA). In this study, we noted that synovial macrophages can activate pyroptosis in a gasdermin D-dependent manner and produce reactive oxygen species (ROS), aberrantly activating the mammalian target of rapamycin complex 1 (mTORC1) pathway and matrix metalloproteinase-9 (MMP9) expression in synovial tissue samples collected from both patients with OA and collagen-induced osteoarthritis (CIOA) mouse model. To overcome this, we constructed rapamycin- (RAPA, a mTORC1 inhibitor) loaded mesoporous Prussian blue nanoparticles (MPB NPs, for catalyzing ROS) and modified the NPs with MMP9-targeted peptides (favor macrophage targeting) to develop RAPA@MPB-MMP9 NPs. The inherent enzyme-like activity and RAPA released from RAPA@MPB-MMP9 NPs synergistically impeded the pyroptosis of macrophages and the activation of the mTORC1 pathway. In particular, the NPs decreased pyroptosis-mediated ROS generation, thereby inhibiting cGAS-STING signaling pathway activation caused by the release of mitochondrial DNA. Moreover, the NPs promoted macrophage mitophagy to restore mitochondrial stability, alleviate pyroptosis-related inflammatory responses, and decrease senescent synoviocytes. After the as-prepared NPs were intra-articularly injected into the CIOA mouse model, they efficiently attenuated synovial macrophage pyroptosis and cartilage degradation. In conclusion, our study findings provide a novel therapeutic strategy for OA that modulates the pyroptosis and mitophagy of synovial macrophage by utilizing functionalized NPs. STATEMENT OF SIGNIFICANCE: Osteoarthritis (OA) presents a significant global challenge owing to its complex pathogenesis and finite treatment options. Synovial macrophages have emerged as key players in the progression of OA, managing inflammation and tissue destruction. In this study, we discovered a novel therapeutic strategy in which the pyroptosis and mitophagy of synovial macrophages are targeted to mitigate OA pathology. For this, we designed and prepared rapamycin-loaded mesoporous Prussian blue nanoparticles (RAPA@MPB-MMP9 NPs) to specifically target synovial macrophages and modulate their inflammatory responses. These NPs could efficiently suppress macrophage pyroptosis, diminish reactive oxygen species production, and promote mitophagy, thereby alleviating inflammation and protecting cartilage integrity. Our study findings not only clarify the intricate mechanisms underlying OA pathogenesis but also present a promising therapeutic approach for effectively managing OA by targeting dysregulation in synovial macrophages.
    Keywords:  Osteoarthritis; Prussian blue nanoparticles; mitophagy; pyroptosis; synovial macrophages
    DOI:  https://doi.org/10.1016/j.actbio.2024.05.014
  53. Am J Cancer Res. 2024 ;14(4): 1935-1946
    Verteporfin suppressed mitophagy via PINK1/parkin pathway in endometrial cancer.
    Ming-Ming Zhao, Bo Wang, Wen-Xi Huang, Li Zhang, Rui Peng, Chao Wang.
      Endometrial cancer (EC) is a malignancy that poses a threat to woman's health worldwide. Building upon prior work, we explored the inhibitory effect of verteporfin on EC. We showed that verteporfin can damage the mitochondria of EC cells, leading to a decrease of mitochondrial membrane potential and an increase in ROS (reactive oxygen species). In addition, verteporfin treatment was shown to inhibit the proliferation and migration of EC cells, promote apoptosis, and reduce the expression of mitophagy-related proteins PINK1/parkin and TOM20. The ROS inhibitor N-Acetyl Cysteine was able to rescue the expression of PINK1/parkin proteins. This suggests that verteporfin may inhibit mitophagy by elevating ROS levels, thereby inhibiting EC cell viability. The effect of verteporfin on mitophagy supports further investigation as a potential therapeutic option for EC.
    Keywords:  Endometrial cancer; PINK1/parkin pathway; mitophagy; verteporfin
    DOI:  https://doi.org/10.62347/PMYV3832
  54. Sci Adv. 2024 May 10. 10(19): eadh0798
    Perinuclear damage from nuclear envelope deterioration elicits stress responses that contribute to LMNA cardiomyopathy.
    Kunal Sikder, Elizabeth Phillips, Zhijiu Zhong, Nadan Wang, Jasmine Saunders, David Mothy, Andrew Kossenkov, Timothy Schneider, Zuzana Nichtova, Gyorgy Csordas, Kenneth B Margulies, Jason C Choi.
      Mutations in the LMNA gene encoding lamins A/C cause an array of tissue-selective diseases, with the heart being the most commonly affected organ. Despite progress in understanding the perturbations emanating from LMNA mutations, an integrative understanding of the pathogenesis underlying cardiac dysfunction remains elusive. Using a novel conditional deletion model capable of translatome profiling, we observed that cardiomyocyte-specific Lmna deletion in adult mice led to rapid cardiomyopathy with pathological remodeling. Before cardiac dysfunction, Lmna-deleted cardiomyocytes displayed nuclear abnormalities, Golgi dilation/fragmentation, and CREB3-mediated stress activation. Translatome profiling identified MED25 activation, a transcriptional cofactor that regulates Golgi stress. Autophagy is disrupted in the hearts of these mice, which can be recapitulated by disrupting the Golgi. Systemic administration of modulators of autophagy or ER stress significantly delayed cardiac dysfunction and prolonged survival. These studies support a hypothesis wherein stress responses emanating from the perinuclear space contribute to the LMNA cardiomyopathy development.
    DOI:  https://doi.org/10.1126/sciadv.adh0798
  55. iScience. 2024 May 17. 27(5): 109659
    Fasting-induced RNF152 resensitizes gallbladder cancer cells to gemcitabine by inhibiting mTORC1-mediated glycolysis.
    Ying Tao, Zijun Gong, Sheng Shen, Yaqi Ding, Rui Zan, Bohao Zheng, Wentao Sun, Chaolin Ma, Mengxuan Shu, Xiao Lu, Han Liu, Xiaoling Ni, Houbao Liu, Tao Suo.
      Abnormal mTORC1 activation by the lysosomal Ragulator complex has been implicated in cancer and glycolytic metabolism associated with drug resistance. Fasting upregulates RNF152 and mediates the metabolic status of cells. We report that RNF152 regulates mTORC1 signaling by targeting a Ragulator subunit, p18, and attenuates gemcitabine resistance in gallbladder cancer (GBC). We detected levels of RNF152 and p18 in tissues and undertook mechanistic studies using activators, inhibitors, and lentivirus transfections. RNF152 levels were significantly lower in GBC than in adjacent non-cancer tissues. Fasting impairs glycolysis, induces gemcitabine sensitivity, and upregulates RNF152 expression. RNF152 overexpression increases the sensitivity of GBC cells to gemcitabine, whereas silencing RNF152 has the opposite effect. Fasting-induced RNF152 ubiquitinates p18, resulting in proteasomal degradation. RNF152 deficiency increases the lysosomal localization of p18 and increases mTORC1 activity, to promote glycolysis and decrease gemcitabine sensitivity. RNF152 suppresses mTORC1 activity to inhibit glycolysis and enhance gemcitabine sensitivity in GBC.
    Keywords:  Cancer; Cell biology; Molecular biology
    DOI:  https://doi.org/10.1016/j.isci.2024.109659
  56. Nat Commun. 2024 May 07. 15(1): 3802
    Structural basis for the intracellular regulation of ferritin degradation.
    Fabian Hoelzgen, Thuy T P Nguyen, Elina Klukin, Mohamed Boumaiza, Ayush K Srivastava, Elizabeth Y Kim, Ran Zalk, Anat Shahar, Sagit Cohen-Schwartz, Esther G Meyron-Holtz, Fadi Bou-Abdallah, Joseph D Mancias, Gabriel A Frank.
      The interaction between nuclear receptor coactivator 4 (NCOA4) and the iron storage protein ferritin is a crucial component of cellular iron homeostasis. The binding of NCOA4 to the FTH1 subunits of ferritin initiates ferritinophagy-a ferritin-specific autophagic pathway leading to the release of the iron stored inside ferritin. The dysregulation of NCOA4 is associated with several diseases, including neurodegenerative disorders and cancer, highlighting the NCOA4-ferritin interface as a prime target for drug development. Here, we present the cryo-EM structure of the NCOA4-FTH1 interface, resolving 16 amino acids of NCOA4 that are crucial for the interaction. The characterization of mutants, designed to modulate the NCOA4-FTH1 interaction, is used to validate the significance of the different features of the binding site. Our results explain the role of the large solvent-exposed hydrophobic patch found on the surface of FTH1 and pave the way for the rational development of ferritinophagy modulators.
    DOI:  https://doi.org/10.1038/s41467-024-48151-1
  57. Aging (Albany NY). 2024 May 09. 16
    Caloric restriction mitigates age-associated senescence characteristics in subcutaneous adipose tissue-derived stem cells.
    Somaiah Chinnapaka, Hamid Malekzadeh, Zayaan Tirmizi, Asim Ejaz.
      Adipose tissue regulates metabolic balance, but aging disrupts it, shifting fat from insulin-sensitive subcutaneous to insulin-resistant visceral depots, impacting overall metabolic health. Adipose-derived stem cells (ASCs) are crucial for tissue regeneration, but aging diminishes their stemness and regeneration potential. Our findings reveal that aging is associated with a decrease in subcutaneous adipose tissue mass and an increase in the visceral fat depots mass. Aging is associated with increase in adipose tissue fibrosis but no significant change in adipocyte size was observed with age. Long term caloric restriction failed to prevent fibrotic changes but resulted in significant decrease in adipocytes size. Aged subcutaneous ASCs displayed an increased production of ROS. Using mitochondrial membrane activity as an indicator of stem cell quiescence and senescence, we observed a significant decrease in quiescence ASCs with age exclusively in subcutaneous adipose depot. In addition, aged subcutaneous adipose tissue accumulated more senescent ASCs having defective autophagy activity. However, long-term caloric restriction leads to a reduction in mitochondrial activity in ASCs. Furthermore, caloric restriction prevents the accumulation of senescent cells and helps retain autophagy activity in aging ASCs. These results suggest that caloric restriction and caloric restriction mimetics hold promise as a potential strategy to rejuvenate the stemness of aged ASCs. Further investigations, including in vivo evaluations using controlled interventions in animals and human studies, will be necessary to validate these findings and establish the clinical potential of this well-established approach for enhancing the stemness of aged stem cells.
    Keywords:  adipose stem cells; adipose tissue; autophagy; caloric restriction; differentiation; reactive oxygen species; senescence; stemness
    DOI:  https://doi.org/10.18632/aging.205812
  58. NPJ Aging. 2024 May 04. 10(1): 24
    EPB41L4A-AS1 is required to maintain basal autophagy to modulates Aβ clearance.
    Ziqiang Wang, Ruomei Wang, Lixin Niu, Xiaoyan Zhou, Jinxiang Han, Kun Li.
      Alzheimer's disease (AD) is the most common neurodegenerative disorder characterized by the deposition of β-amyloid (Aβ) plaques. Aβ is generated from the cleavage of the amyloid precursor protein by β and γ-secretases and cleared by neuroglial cells mediated autophagy. The imbalance of the intracellular Aβ generation and clearance is the causative factor for AD pathogenesis. However, the exact underlying molecular mechanisms remain unclear. Our previous study reported that EPB41L4A-AS1 is an aging-related long non-coding RNA (lncRNA) that is repressed in patients with AD. In this study, we found that downregulated EPB41L4A-AS1 in AD inhibited neuroglial cells mediated-Aβ clearance by decreasing the expression levels of multiple autophagy-related genes. We found that EPB41L4A-AS1 regulates the expression of general control of amino acid synthesis 5-like 2, an important histone acetyltransferase, thus affecting histone acetylation, crotonylation, and lactylation near the transcription start site of autophagy-related genes, ultimately influencing their transcription. Collectively, this study reveals EPB41L4A-AS1 as an AD-related lncRNA via mediating Aβ clearance and provides insights into the epigenetic regulatory mechanism of EPB41L4A-AS1 in gene expression and AD pathogenesis.
    DOI:  https://doi.org/10.1038/s41514-024-00152-6
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