bims-auttor Biomed News
on Autophagy and mTOR
Issue of 2024–07–07
57 papers selected by
Viktor Korolchuk, Newcastle University
  1. Structures and Functions of the Human GATOR1 Complex.
  2. TBC1D4 antagonizes RAB2A-mediated autophagic and endocytic pathways.
  3. Methods to Assess Autophagic Activity in Dictyostelium.
  4. Phospholipid Supply for Autophagosome Biogenesis.
  5. Maturation and Assembly of mTOR Complexes by the HSP90-R2TP-TTT Chaperone System: Molecular Insights and Mechanisms.
  6. TFEB safeguards trophoblast syncytialization in humans and mice.
  7. Comprehensive knockout analysis of the RAB family small GTPases reveals an overlapping role of RAB2 and RAB14 in autophagosome maturation.
  8. No energy, no autophagy-Mechanisms and therapeutic implications of autophagic response energy requirements.
  9. From macroautophagy to mitophagy: Unveiling the hidden role of mitophagy in gastrointestinal disorders.
  10. An APEX2-based proximity-dependent biotinylation assay with temporal specificity to study protein interactions during autophagy in the yeast Saccharomyces cerevisiae.
  11. Individual Atg8 paralogs exhibit unique properties in streptococcus pneumoniae-induced hierarchical autophagy.
  12. Prohibitins, Phb1 and Phb2, function as Atg8 receptors to support yeast mitophagy and also play a negative regulatory role in Atg32 processing.
  13. Calcium (Ca2+) hemostasis, mitochondria, autophagy, and mitophagy contribute to Alzheimer's disease as early moderators.
  14. Adult-onset deactivation of autophagy leads to loss of synapse homeostasis and cognitive impairment, with implications for alzheimer disease.
  15. FUNDC1 alleviates doxorubicin-induced cardiotoxicity by restoring mitochondrial-endoplasmic reticulum contacts and blocked autophagic flux.
  16. Electrostatic maturation of the autophagosome.
  17. ATF4-mediated different mode of interaction between autophagy and mTOR determines cell fate dependent on the level of ER stress induced by Cr(VI).
  18. Hyperactive mTORC1 disrupts habenula function and light preference in zebrafish model of Tuberous sclerosis complex.
  19. Disturbed intracellular folate homeostasis impairs autophagic flux and increases hepatocytic lipid accumulation.
  20. Dihydropyrazine induces endoplasmic reticulum stress and inhibits autophagy in HepG2 human hepatoma cells.
  21. Retinal cells derived from patients with DRAM2-dependent CORD21 dystrophy exhibit key lysosomal enzyme deficiency and lysosomal content accumulation.
  22. Autophagy and mitophagy as potential therapeutic targets in diabetic heart condition: Harnessing the power of nanotheranostics.
  23. The 18S rRNA Methyltransferase DIMT-1 Regulates Lifespan in the Germline Later in Life.
  24. Duck STING mediates antiviral autophagy directing the interferon signaling pathway to inhibit duck plague virus infection.
  25. Activation of the NLRP3-CASP-1 inflammasome is restrained by controlling autophagy during Glaesserella parasuis infection.
  26. Lysosomal dysfunction-derived autophagy impairment of gingival epithelial cells in diabetes-associated periodontitis with altered protein acetylation.
  27. Phytochemical-mediated modulation of autophagy and endoplasmic reticulum stress as a cancer therapeutic approach.
  28. Autophagy Regulation Attenuates Neuroinflammation and Cognitive Decline in an Alzheimer's Disease Mouse Model with Chronic Cerebral Hypoperfusion.
  29. Trypanosoma cruzi Vps34 colocalizes with Beclin1 and plays a role in parasite invasion of the host cell by modulating the expression of a sub-group of trans-sialidases.
  30. FOXO-regulated DEAF1 controls muscle regeneration through autophagy.
  31. Mitochondrial‑associated endoplasmic reticulum membrane interference in ovarian cancer (Review).
  32. A hitchhiker's guide to autophagy.
  33. A mitochondrial checkpoint to NF-κB signaling.
  34. HLH-30/TFEB mediates sexual dimorphism in immunity in caenorhabditis elegans.
  35. The role of BCAA metabolism in metabolic health and disease.
  36. Editorial: Autophagy in endocrine-metabolic diseases associated with aging: Volume II.
  37. Insights into the role of mitophagy in lung cancer: current evidence and perspectives.
  38. Tanshinone I improves TNBC chemosensitivity by suppressing late-phase autophagy through AKT/p38 MAPK signaling pathway.
  39. Atg8/LC3 controls systemic nutrient surplus signaling in flies and humans.
  40. Knockdown of NUF2-derived exosomes can inhibit the migration and autophagy of BC cells and improve resistance to doxorubicin.
  41. DKK1 loss promotes endometrial fibrosis via autophagy and exosome-mediated macrophage-to-myofibroblast transition.
  42. Macrophage migration inhibitory factor (MIF) suppresses mitophagy through disturbing the protein interaction of PINK1-Parkin in sepsis-associated acute kidney injury.
  43. Phagolysosomes break down the membrane of a non-apoptotic corpse independent of macroautophagy.
  44. Protein modification and degradation in ferroptosis.
  45. TRIM26 facilitates PRV infection through NDP52-mediated autophagic degradation of MAVS.
  46. Extensive location bias of the GPCR-dependent translatome via site-selective activation of mTOR.
  47. Lysosomal cation channel TRPML1 suppression sensitizes acute myeloid leukemia cells to chemotherapeutics by inhibiting autophagy.
  48. Assaying Lysosomal Enzyme Activity in Dictyostelium discoideum.
  49. A lysosomal-targeted and viscosity-ultrasensitive near-infrared fluorescent probe for sensing viscosity in cells and a diabetic mice model.
  50. Metabolic stress induces a double-positive feedback loop between AMPK and SQSTM1/p62 conferring dual activation of AMPK and NFE2L2/NRF2 to synergize antioxidant defense.
  51. BI1 Activates Autophagy and Mediates TDP43 to Regulate ALS Pathogenesis.
  52. The Interplay of Acetylation and Ubiquitination Controls PRMT1 Homeostasis.
  53. A Dual-Labeling Molecule for Efficient Drug Discovery of Mitochondrial-Lysosomal Interactions.
  54. TFEB controls syncytiotrophoblast formation and hormone production in placenta.
  55. Ruthenium complex containing 1,3-thiazolidine-2-thione inhibits hepatic cancer stem cells by suppressing Akt/mTOR signalling and leading to apoptotic and autophagic cell death.
  56. Enhancing neuronal reticulophagy: a strategy for combating aging and APP toxicity.
  57. Trametinib boosts palbociclib's efficacy in breast cancer via autophagy inhibition.
  1. Subcell Biochem. 2024 ;104 269-294
    Structures and Functions of the Human GATOR1 Complex.
    Ilina Ivanova, Kuang Shen.
      Eukaryotic cells coordinate available nutrients with their growth through the mechanistic target of rapamycin complex 1 (mTORC1) pathway, in which numerous evolutionarily conserved protein complexes survey and transmit nutrient inputs toward mTORC1. mTORC1 integrates these inputs and activates downstream anabolic or catabolic programs that are in tune with cellular needs, effectively maintaining metabolic homeostasis. The GAP activity toward Rags-1 (GATOR1) protein complex is a critical negative regulator of the mTORC1 pathway and, in the absence of amino acid inputs, is activated to turn off mTORC1 signaling. GATOR1-mediated inhibition of mTORC1 signaling is tightly regulated by an ensemble of protein complexes that antagonize or promote its activity in response to the cellular nutrient environment. Structural, biochemical, and biophysical studies of the GATOR1 complex and its interactors have advanced our understanding of how it regulates cellular metabolism when amino acids are limited. Here, we review the current research with a focus on GATOR1 structure, its enzymatic mechanism, and the growing group of proteins that regulate its activity. Finally, we discuss the implication of GATOR1 dysregulation in physiology and human diseases.
    Keywords:  Enzyme mechanism; GATOR1; GTPase activating protein (GAP); Protein structure; Rag GTPases; mTORC1
    DOI:  https://doi.org/10.1007/978-3-031-58843-3_12
  2. Autophagy. 2024 Jul 04. 1-18
    TBC1D4 antagonizes RAB2A-mediated autophagic and endocytic pathways.
    Rui Tian, Pengwei Zhao, Xianming Ding, Xinyi Wang, Xiao Jiang, Shuai Chen, Zhijian Cai, Lin Li, She Chen, Wei Liu, Qiming Sun.
      Macroautophagic/autophagic and endocytic pathways play essential roles in maintaining homeostasis at different levels. It remains poorly understood how both pathways are coordinated and fine-tuned for proper lysosomal degradation of diverse cargoes. We and others recently identified a Golgi-resident RAB GTPase, RAB2A, as a positive regulator that controls both autophagic and endocytic pathways. In the current study, we report that TBC1D4 (TBC1 domain family member 4), a TBC domain-containing protein that plays essential roles in glucose homeostasis, suppresses RAB2A-mediated autophagic and endocytic pathways. TBC1D4 bound to RAB2A through its N-terminal PTB2 domain, which impaired RAB2A-mediated autophagy at the early stage by preventing ULK1 complex activation. During the late stage of autophagy, TBC1D4 impeded the association of RUBCNL/PACER and RAB2A with STX17 on autophagosomes by direct interaction with RUBCNL via its N-terminal PTB1 domain. Disruption of the autophagosomal trimeric complex containing RAB2A, RUBCNL and STX17 resulted in defective HOPS recruitment and eventually abortive autophagosome-lysosome fusion. Furthermore, TBC1D4 inhibited RAB2A-mediated endocytic degradation independent of RUBCNL. Therefore, TBC1D4 and RAB2A form a dual molecular switch to modulate autophagic and endocytic pathways. Importantly, hepatocyte- or adipocyte-specific tbc1d4 knockout in mice led to elevated autophagic flux and endocytic degradation and tissue damage. Together, this work establishes TBC1D4 as a critical molecular brake in autophagic and endocytic pathways, providing further mechanistic insights into how these pathways are intertwined both in vitro and in vivo.Abbreviations: ACTB: actin beta; ATG9: autophagy related 9; ATG14: autophagy related 14; ATG16L1: autophagy related 16 like 1; CLEM: correlative light electron microscopy; Ctrl: control; DMSO: dimethyl sulfoxide; EGF: epidermal growth factor; EGFR: epidermal growth factor receptor; FL: full length; GAP: GTPase-activating protein; GFP: green fluorescent protein; HOPS: homotypic fusion and protein sorting; IP: immunoprecipitation; KD: knockdown; KO: knockout; LAMP1: lysosomal associated membrane protein 1; MAP1LC3B/LC3B: microtubule associated protein 1 light chain 3 beta; OE: overexpression; PG: phagophore; PtdIns3K: class III phosphatidylinositol 3-kinase; SLC2A4/GLUT4: solute carrier family 2 member 4; SQSTM1/p62: sequestosome 1; RUBCNL/PACER: rubicon like autophagy enhancer; STX17: syntaxin 17; TAP: tandem affinity purification; TBA: total bile acid; TBC1D4: TBC1 domain family member 4; TUBA1B: tubulin alpha 1b; ULK1: unc-51 like autophagy activating kinase 1; VPS39: VPS39 subunit of HOPS complex; WB: western blot; WT: wild type.
    Keywords:  Autophagosome-lysosome fusion; RAB2A; TBC1D4; autophagy; endocytic pathway
    DOI:  https://doi.org/10.1080/15548627.2024.2367907
  3. Methods Mol Biol. 2024 ;2814 97-106
    Methods to Assess Autophagic Activity in Dictyostelium.
    Laura Antón-Esteban, Alba Tornero-Écija, Olivier Vincent, Ricardo Escalante.
      Autophagy is an intracellular clearance and recycling pathway that delivers different types of cargos to lysosomes for degradation. In recent years, autophagy has attracted considerable medical interest, and many different techniques are being developed to study this process in experimental models such as Dictyostelium. Here we describe the use of different autophagic markers in confocal microscopy, in vivo and also in fixed cells. In particular, we describe the use of the GFP-Atg8-RFP-Atg8ΔG marker and the optimization of the GFP-PgkA cleavage assay to detect small differences in autophagy flux.
    Keywords:  Autophagic flux; Autophagosome; Autophagy; Dictyostelium
    DOI:  https://doi.org/10.1007/978-1-0716-3894-1_7
  4. J Mol Biol. 2024 Jun 27. pii: S0022-2836(24)00293-6. [Epub ahead of print] 168691
    Phospholipid Supply for Autophagosome Biogenesis.
    Damilola Isola, Zvulun Elazar.
      Autophagy is a cellular degradation pathway where double-membrane autophagosomes form de novo to engulf cytoplasmic material destined for lysosomal degradation. This process requires regulated membrane remodeling, beginning with the initial autophagosomal precursor and progressing to its elongation and maturation into a fully enclosed, fusion-capable vesicle. While the core protein machinery involved in autophagosome formation has been extensively studied over the past two decades, the role of phospholipids in this process has only recently been studied. This review focuses on the phospholipid composition of the phagophore membrane and the mechanisms that supply lipids to expand this unique organelle.
    Keywords:  ATG2; ATG9; autophagy; isolation membrane; phospholipids
    DOI:  https://doi.org/10.1016/j.jmb.2024.168691
  5. Subcell Biochem. 2024 ;104 459-483
    Maturation and Assembly of mTOR Complexes by the HSP90-R2TP-TTT Chaperone System: Molecular Insights and Mechanisms.
    Andrés López-Perrote, Marina Serna, Oscar Llorca.
      The mechanistic target of rapamycin (mTOR) is a master regulator of cell growth and metabolism, integrating environmental signals to regulate anabolic and catabolic processes, regulating lipid synthesis, growth factor-induced cell proliferation, cell survival, and migration. These activities are performed as part of two distinct complexes, mTORC1 and mTORC2, each with specific roles. mTORC1 and mTORC2 are elaborated dimeric structures formed by the interaction of mTOR with specific partners. mTOR functions only as part of these large complexes, but their assembly and activation require a dedicated and sophisticated chaperone system. mTOR folding and assembly are temporarily separated with the TELO2-TTI1-TTI2 (TTT) complex assisting the cotranslational folding of mTOR into a native conformation. Matured mTOR is then transferred to the R2TP complex for assembly of active mTORC1 and mTORC2 complexes. R2TP works in concert with the HSP90 chaperone to promote the incorporation of additional subunits to mTOR and dimerization. This review summarizes our current knowledge on how the HSP90-R2TP-TTT chaperone system facilitates the maturation and assembly of active mTORC1 and mTORC2 complexes, discussing interactions, structures, and mechanisms.
    Keywords:  Chaperones; HSP90; R2TP; RUVBL1; RUVBL2; TELO2; TTT; mTORC1; mTORC2
    DOI:  https://doi.org/10.1007/978-3-031-58843-3_17
  6. Proc Natl Acad Sci U S A. 2024 Jul 09. 121(28): e2404062121
    TFEB safeguards trophoblast syncytialization in humans and mice.
    Wanshan Zheng, Yue Zhang, Peiqun Xu, Zexin Wang, Xuan Shao, Chunyan Chen, Han Cai, Yinan Wang, Ming-An Sun, Wenbo Deng, Fan Liu, Jinhua Lu, Xueqin Zhang, Dunjin Cheng, Indira U Mysorekar, Haibin Wang, Yan-Ling Wang, Xiaoqian Hu, Bin Cao.
      Nutrient sensing and adaptation in the placenta are essential for pregnancy viability and proper fetal growth. Our recent study demonstrated that the placenta adapts to nutrient insufficiency through mechanistic target of rapamycin (mTOR) inhibition-mediated trophoblast differentiation toward syncytiotrophoblasts (STBs), a highly specialized multinucleated trophoblast subtype mediating extensive maternal-fetal interactions. However, the underlying mechanism remains elusive. Here, we unravel the indispensable role of the mTORC1 downstream transcriptional factor TFEB in STB formation both in vitro and in vivo. TFEB deficiency significantly impaired STB differentiation in human trophoblasts and placenta organoids. Consistently, systemic or trophoblast-specific deletion of Tfeb compromised STB formation and placental vascular construction, leading to severe embryonic lethality. Mechanistically, TFEB conferred direct transcriptional activation of the fusogen ERVFRD-1 in human trophoblasts and thereby promoted STB formation, independent of its canonical function as a master regulator of the autophagy-lysosomal pathway. Moreover, we demonstrated that TFEB directed the trophoblast syncytialization response driven by mTOR complex 1 (mTORC1) signaling. TFEB expression positively correlated with the reinforced trophoblast syncytialization in human fetal growth-restricted placentas exhibiting suppressed mTORC1 activity. Our findings substantiate that the TFEB-fusogen axis ensures proper STB formation during placenta development and under nutrient stress, shedding light on TFEB as a mechanistic link between nutrient-sensing machinery and trophoblast differentiation.
    Keywords:  ERVFRD-1; TFEB; fetal growth restriction; human trophoblast stem cell; syncytiotrophoblast
    DOI:  https://doi.org/10.1073/pnas.2404062121
  7. Autophagy. 2024 Jul 02.
    Comprehensive knockout analysis of the RAB family small GTPases reveals an overlapping role of RAB2 and RAB14 in autophagosome maturation.
    Kentaro Haga, Mitsunori Fukuda.
      Macroautophagy, simply referred to below as autophagy, is an intracellular degradation system that is highly conserved in eukaryotes. Since the processes involved in autophagy are accompanied by membrane dynamics, RAB small GTPases, key regulators of membrane trafficking, are generally thought to regulate the membrane dynamics of autophagy. Although more than half of the mammalian RABs have been reported to be involved in canonical and selective autophagy, no consensus has been reached in regard to the role of RABs in mammalian autophagy. Here, we comprehensively analyzed a rab-knockout (KO) library of MDCK cells to reevaluate the requirement for each RAB isoform in basal and starvation-induced autophagy. The results revealed clear alteration of the MAP1LC3/LC3-II level in only four rab-KO cells (rab1-KO, rab2-KO, rab7a-KO, and rab14-KO cells) and identified RAB14 as a new regulator of autophagy, specifically at the autophagosome maturation step. The autophagy-defective phenotype of two of these rab-KO cells, rab2-KO and rab14-KO cells, was very mild, but double KO of rab2 and rab14 caused a severer autophagy-defective phenotype (greater LC3 accumulation than in single-KO cells, indicating an overlapping role of RAB2 and RAB14 during autophagosome maturation. We also found that RAB14 is phylogenetically similar to RAB2 and that it possesses the same properties as RAB2, i.e. autophagosome localization and interaction with the HOPS subunits VPS39 and VPS41. Our findings suggest that RAB2 and RAB14 overlappingly regulate the autophagosome maturation step through recruitment of the HOPS complex to the autophagosome.
    Keywords:  Autophagosome maturation; endosome; gene knockout (KO); lysosome; membrane trafficking; small GTPase RAB
    DOI:  https://doi.org/10.1080/15548627.2024.2374699
  8. J Cell Physiol. 2024 Jul 03. e31366
    No energy, no autophagy-Mechanisms and therapeutic implications of autophagic response energy requirements.
    Milos Mandic, Verica Paunovic, Ljubica Vucicevic, Milica Kosic, Srdjan Mijatovic, Vladimir Trajkovic, Ljubica Harhaji-Trajkovic.
      Autophagy is a lysosome-mediated self-degradation process of central importance for cellular quality control. It also provides macromolecule building blocks and substrates for energy metabolism during nutrient or energy deficiency, which are the main stimuli for autophagy induction. However, like most biological processes, autophagy itself requires ATP, and there is an energy threshold for its initiation and execution. We here present the first comprehensive review of this often-overlooked aspect of autophagy research. The studies in which ATP deficiency suppressed autophagy in vitro and in vivo were classified according to the energy pathway involved (oxidative phosphorylation or glycolysis). A mechanistic insight was provided by pinpointing the critical ATP-consuming autophagic events, including transcription/translation/interaction of autophagy-related molecules, autophagosome formation/elongation, autophagosome fusion with the lysosome, and lysosome acidification. The significance of energy-dependent fine-tuning of autophagic response for preserving the cell homeostasis, and potential implications for the therapy of cancer, autoimmunity, metabolic disorders, and neurodegeneration are discussed.
    Keywords:  AMP‐activated protein kinase; ATP; autophagy; energy stress; glycolysis; oxidative phosphorylation
    DOI:  https://doi.org/10.1002/jcp.31366
  9. World J Gastroenterol. 2024 Jun 21. 30(23): 2934-2946
    From macroautophagy to mitophagy: Unveiling the hidden role of mitophagy in gastrointestinal disorders.
    Duo-Lun Gao, Meng-Ran Lin, Nan Ge, Jin-Tao Guo, Fan Yang, Si-Yu Sun.
      In this editorial, we comment on an article titled "Morphological and biochemical characteristics associated with autophagy in gastrointestinal diseases", which was published in a recent issue of the World Journal of Gastroenterology. We focused on the statement that "autophagy is closely related to the digestion, secretion, and regeneration of gastrointestinal cells". With advancing research, autophagy, and particularly the pivotal role of the macroautophagy in maintaining cellular equilibrium and stress response in the gastrointestinal system, has garnered extensive study. However, the significance of mitophagy, a unique selective autophagy pathway with ubiquitin-dependent and independent variants, should not be overlooked. In recent decades, mitophagy has been shown to be closely related to the occurrence and development of gastrointestinal diseases, especially inflammatory bowel disease, gastric cancer, and colorectal cancer. The interplay between mitophagy and mitochondrial quality control is crucial for elucidating disease mechanisms, as well as for the development of novel treatment strategies. Exploring the pathogenesis behind gastrointestinal diseases and providing individualized and efficient treatment for patients are subjects we have been exploring. This article reviews the potential mechanism of mitophagy in gastrointestinal diseases with the hope of providing new ideas for diagnosis and treatment.
    Keywords:  Autophagic receptor; Colorectal cancer; Gastric cancer; Gastrointestinal diseases; Inflammatory bowel disease; Mitophagy; Parkin
    DOI:  https://doi.org/10.3748/wjg.v30.i23.2934
  10. Autophagy. 2024 Jul 03. 1-16
    An APEX2-based proximity-dependent biotinylation assay with temporal specificity to study protein interactions during autophagy in the yeast Saccharomyces cerevisiae.
    Yasmina Filali-Mouncef, Alexandre Leytens, Prado Vargas Duarte, Mattia Zampieri, Jörn Dengjel, Fulvio Reggiori.
      Autophagosome biogenesis is a complex process orchestrated by dynamic interactions between Atg (autophagy-related) proteins and characterized by the turnover of specific cargoes, which can differ over time and depending on how autophagy is stimulated. Proteomic analyses are central to uncover protein-protein interaction networks and when combined with proximity-dependent biotinylation or proximity labeling (PL) approaches, they also permit to detect transient and weak interactions. However, current PL procedures for yeast Saccharomyces cerevisiae, one of the leading models for the study of autophagy, do not allow to keep temporal specificity and thus identify interactions and cargoes at a precise time point upon autophagy induction. Here, we present a new ascorbate peroxidase 2 (APEX2)-based PL protocol adapted to yeast that preserves temporal specificity and allows uncovering neighbor proteins by either western blot or proteomics. As a proof of concept, we applied this new method to identify Atg8 and Atg9 interactors and detected known binding partners as well as potential uncharacterized ones in rich and nitrogen starvation conditions. Also, as a proof of concept, we confirmed the spatial proximity interaction between Atg8 and Faa1. We believe that this protocol will be a new important experimental tool for all those researchers studying the mechanism and roles of autophagy in yeast, but also other cellular pathways in this model organism.Abbreviations: APEX2, ascorbate peroxidase 2, Atg, autophagy-related; BP, biotin phenol; Cvt, cytoplasm-to-vacuole targeting; ER, endoplasmic reticulum; LN2, liquid nitrogen; MS, mass spectrometry; PAS, phagophore assembly site; PL, proximity labeling; PE, phosphatidylethanolamine; PPINs, protein-protein interaction networks; PPIs, protein-protein interactions; RT, room temperature; SARs, selective autophagy receptors; WT, wild-type.
    Keywords:  Atg proteins; Atg8; Atg9; mass spectrometry; proteomics; proximity labeling
    DOI:  https://doi.org/10.1080/15548627.2024.2366749
  11. Autophagy. 2024 Jul 04.
    Individual Atg8 paralogs exhibit unique properties in streptococcus pneumoniae-induced hierarchical autophagy.
    Sayaka Shizukuishi, Michinaga Ogawa, Yukihiro Akeda.
      Individual Atg8 (autophagy related 8) paralogs, comprising MAP1LC3A/LC3A, LC3B, LC3C, GABARAP, GABARAPL1 and GABARAPL2/GATE16, play a crucial role in canonical macroautophagy/autophagy. However, their functions remain unclear owing to functional redundancy. In a previous study, we reported that intracellular Streptococcus pneumoniae triggers hierarchical autophagy in response to bacterial infection. This process commences with the induction of conjugation of Atg8 paralogs (Atg8s) to single membranes (CASM), followed by CASM shedding and subsequent induction of xenophagy. In our recent study, we performed functional analysis of Atg8s during pneumococci-induced hierarchical autophagy. Our findings suggest that LC3A and GABARAPL1 are crucial for CASM induction, whereas GABARAPL2 and GABARAP play sequential roles in CASM shedding and subsequent induction of xenophagy, respectively.
    Keywords:  Atg8s; CASM; Xenophagy; streptococcus pneumoniae
    DOI:  https://doi.org/10.1080/15548627.2024.2375707
  12. Autophagy. 2024 Jul 04. 1-12
    Prohibitins, Phb1 and Phb2, function as Atg8 receptors to support yeast mitophagy and also play a negative regulatory role in Atg32 processing.
    Diana García-Chávez, Eunice Domínguez-Martín, Laura Kawasaki, Laura Ongay-Larios, Hilario Ruelas-Ramírez, Ariann E Mendoza-Martinez, Juan P Pardo, Soledad Funes, Roberto Coria.
      The prohibitins Phb1 and Phb2 assemble at the mitochondrial inner membrane to form a multi-dimeric complex. These scaffold proteins are highly conserved in eukaryotic cells, from yeast to mammals, and have been implicated in a variety of mitochondrial functions including aging, proliferation, and degenerative and metabolic diseases. In mammals, PHB2 regulates PINK1-PRKN mediated mitophagy by interacting with lipidated MAP1LC3B/LC3B. Despite their high conservation, prohibitins have not been linked to mitophagy in budding yeasts. In this study, we demonstrate that both Phb1 and Phb2 are required to sustain mitophagy in Saccharomyces cerevisiae. Prohibitin-dependent mitophagy requires formation of the Phb1-Phb2 complex and a conserved AIM/LIR-like motif identified in both yeast prohibitins. Furthermore, both Phb1 and Phb2 interact and exhibit mitochondrial colocalization with Atg8. Interestingly, we detected a basal C terminus processing of the mitophagy receptor Atg32 that depends on the presence of the i-AAA Yme1. In the absence of prohibitins this processing is highly enhanced but reverted by the inactivation of the rhomboid protease Pcp1. Together our results revealed a novel role of yeast prohibitins in mitophagy through its interaction with Atg8 and regulating an Atg32 proteolytic event. Abbreviation: AIM/LIR: Atg8-family interacting motif/LC3-interacting region; ANOVA: analysis of variance; ATG/Atg: autophagy related; C terminus/C-terminal: carboxyl terminus/carboxyl-terminal; GFP: green fluorescent protein; HA: human influenza hemagglutinin; Idh1: isocitrate dehydrogenase 1; MAP1C3B/LC3B: microtubule associated protein 1 light chain 3 beta; mCh: mCherry; MIM: mitochondrial inner membrane; MOM: mitochondrial outer membrane; N starvation: nitrogen starvation; N terminus: amino terminus; PARL: presenilin associated rhomboid like; Pcp1: processing of cytochrome c peroxidase 1; PCR: polymerase chain reaction; PGAM5: PGAM family member 5 mitochondrial serine/threonine protein phosphatase; PHBs/Phb: prohibitins; PINK1: PTEN induced kinase 1; PMSF: phenylmethylsulfonyl fluoride; PRKN: parkin RBR E3 ubiquitin protein ligase; SD: synthetic defined medium; SDS: sodium dodecyl sulfate; SMD-N: synthetic defined medium lacking nitrogen; WB: western blot; WT: wild type; Yme1: yeast mitochondrial escape 1; YPD: yeast extract-peptone-dextrose medium; YPLac: yeast extract-peptone-lactate medium.
    Keywords:  AIM/LIR motif; PARL; PINK1-PRKN; autophagy; i-AAA protease (Yme1); rhomboid protease (Pcp1)
    DOI:  https://doi.org/10.1080/15548627.2024.2371717
  13. Cell Biochem Funct. 2024 Jul;42(5): e4085
    Calcium (Ca2+) hemostasis, mitochondria, autophagy, and mitophagy contribute to Alzheimer's disease as early moderators.
    Fatemeh Hadi, Mahsa Mortaja, Zahra Hadi.
      This review rigorously investigates the early cerebral changes associated with Alzheimer's disease, which manifest long before clinical symptoms arise. It presents evidence that the dysregulation of calcium (Ca2+) homeostasis, along with mitochondrial dysfunction and aberrant autophagic processes, may drive the disease's progression during its asymptomatic, preclinical stage. Understanding the intricate molecular interplay that unfolds during this critical period offers a window into identifying novel therapeutic targets, thereby advancing the treatment of neurodegenerative disorders. The review delves into both established and emerging insights into the molecular alterations precipitated by the disruption of Ca2+ balance, setting the stage for cognitive decline and neurodegeneration.
    Keywords:  Alzheimer's disease; Ca2+ hemostasis; autophagy; mitochondria; mitophagy; neurodegeneration
    DOI:  https://doi.org/10.1002/cbf.4085
  14. Autophagy. 2024 Jul 01. 1-16
    Adult-onset deactivation of autophagy leads to loss of synapse homeostasis and cognitive impairment, with implications for alzheimer disease.
    Hilary Grosso Jasutkar, Elizabeth M Wasserlein, Azeez Ishola, Nicole Litt, Agnieszka Staniszewski, Ottavio Arancio, Ai Yamamoto.
      A growing number of studies link dysfunction of macroautophagy/autophagy to the pathogenesis of diseases such as Alzheimer disease (AD). Given the global importance of autophagy for homeostasis, how its dysfunction can lead to specific neurological changes is puzzling. To examine this further, we compared the global deactivation of autophagy in the adult mouse using the atg7iKO with the impact of AD-associated pathogenic changes in autophagic processing of synaptic proteins. Isolated forebrain synaptosomes, rather than total homogenates, from atg7iKO mice demonstrated accumulation of synaptic proteins, suggesting that the synapse might be a vulnerable site for protein homeostasis disruption. Moreover, the deactivation of autophagy resulted in impaired cognitive performance over time, whereas gross locomotor skills remained intact. Despite deactivation of autophagy for 6.5 weeks, changes in cognition were in the absence of cell death or synapse loss. In the symptomatic APP PSEN1 double-transgenic mouse model of AD, we found that the impairment in autophagosome maturation coupled with diminished presence of discrete synaptic proteins in autophagosomes isolated from these mice, leading to the accumulation of one of these proteins in the detergent insoluble protein fraction. This protein, SLC17A7/Vglut, also accumulated in atg7iKO mouse synaptosomes. Taken together, we conclude that synaptic autophagy plays a role in maintaining protein homeostasis, and that while decreasing autophagy interrupts normal cognitive function, the preservation of locomotion suggests that not all circuits are affected similarly. Our data suggest that the disruption of autophagic activity in AD may have relevance for the cognitive impairment in this adult-onset neurodegenerative disease. Abbreviations: 2dRAWM: 2-day radial arm water maze; AD: Alzheimer disease; Aβ: amyloid-beta; AIF1/Iba1: allograft inflammatory factor 1; APP: amyloid beta precursor protein; ATG7: autophagy related 7; AV: autophagic vacuole; CCV: cargo capture value; Ctrl: control; DLG4/PSD-95: discs large MAGUK scaffold protein 4; GFAP: glial fibrillary acidic protein; GRIN2B/NMDAR2b: glutamate ionotropic receptor NMDA type subunit 2B; LTD: long-term depression; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; m/o: months-old; PNS: post-nuclear supernatant; PSEN1/PS1: presenilin 1; SHB: sucrose homogenization buffer; SLC32A1/Vgat: solute carrier family 32 member 1; SLC17A7/Vglut1: solute carrier family 17 member 7; SNAP25: synaptosome associated protein 25; SQSTM1/p62: sequestosome 1; SYN1: synapsin I; SYP: synaptophysin ; SYT1: synaptotagmin 1; Tam: tamoxifen; VAMP2: vesicle associated membrane protein 2; VCL: vinculin; wks: weeks.
    Keywords:  Alzheimer disease; autophagy; cognition; hippocampus; synapse homeostasis
    DOI:  https://doi.org/10.1080/15548627.2024.2368335
  15. Theranostics. 2024 ;14(9): 3719-3738
    FUNDC1 alleviates doxorubicin-induced cardiotoxicity by restoring mitochondrial-endoplasmic reticulum contacts and blocked autophagic flux.
    Weibin He, Zhongchan Sun, Guang Tong, Lin Zeng, Wenlong He, Xiaopan Chen, Cien Zhen, Pengyuan Chen, Ning Tan, Pengcheng He.
      Rationale: Autophagy dysregulation is known to be a mechanism of doxorubicin (DOX)-induced cardiotoxicity (DIC). Mitochondrial-Endoplasmic Reticulum Contacts (MERCs) are where autophagy initiates and autophagosomes form. However, the role of MERCs in autophagy dysregulation in DIC remains elusive. FUNDC1 is a tethering protein of MERCs. We aim to investigate the effect of DOX on MERCs in cardiomyocytes and explore whether it is involved in the dysregulated autophagy in DIC. Methods: We employed confocal microscopy and transmission electron microscopy to assess MERCs structure. Autophagic flux was analyzed using the mCherry-EGFP-LC3B fluorescence assay and western blotting for LC3BII. Mitophagy was studied through the mCherry-EGFP-FIS1 fluorescence assay and colocalization analysis between LC3B and mitochondria. A total dose of 18 mg/kg of doxorubicin was administrated in mice to construct a DIC model in vivo. Additionally, we used adeno-associated virus (AAV) to cardiac-specifically overexpress FUNDC1. Cardiac function and remodeling were evaluated by echocardiography and Masson's trichrome staining, respectively. Results: DOX blocked autophagic flux by inhibiting autophagosome biogenesis, which could be attributed to the downregulation of FUNDC1 and disruption of MERCs structures. FUNDC1 overexpression restored the blocked autophagosome biogenesis by maintaining MERCs structure and facilitating ATG5-ATG12/ATG16L1 complex formation without altering mitophagy. Furthermore, FUNDC1 alleviated DOX-induced oxidative stress and cardiomyocytes deaths in an autophagy-dependent manner. Notably, cardiac-specific overexpression of FUNDC1 protected DOX-treated mice against adverse cardiac remodeling and improved cardiac function. Conclusions: In summary, our study identified that FUNDC1-meditated MERCs exerted a cardioprotective effect against DIC by restoring the blocked autophagosome biogenesis. Importantly, this research reveals a novel role of FUNDC1 in enhancing macroautophagy via restoring MERCs structure and autophagosome biogenesis in the DIC model, beyond its previously known regulatory role as an mitophagy receptor.
    Keywords:  FUNDC1; Mitochondrial-Endoplasmic Reticulum Contacts; autophagy; cardiotoxicity; doxorubicin
    DOI:  https://doi.org/10.7150/thno.92771
  16. Autophagy. 2024 Jul 01.
    Electrostatic maturation of the autophagosome.
    Saori Shinoda, Noboru Mizushima.
      In macroautophagy, lysosomes fuse with closed autophagosomes but not with unclosed ones. This is achieved, at least in part, by the temporally regulated recruitment of the autophagosomal SNARE STX17 (syntaxin 17) to only mature autophagosomes. However, the molecular mechanism by which STX17 recognizes autophagosomal maturation remains unknown. Our recent study revealed that STX17 recruitment is regulated by the electrostatic interaction between the positively charged C-terminal region of STX17 and the autophagosomal membrane, which becomes negatively charged during maturation due to the accumulation of phosphatidylinositol-4-phosphate (PtdIns4P). Here, we propose an electrostatic maturation model of the autophagosome.
    Keywords:  Electrostatic interaction; STX17; lysosome; mature autophagosome; membrane charge; phosphatidylinositol-4-phosphate
    DOI:  https://doi.org/10.1080/15548627.2024.2375082
  17. Ecotoxicol Environ Saf. 2024 Jul 03. pii: S0147-6513(24)00715-2. [Epub ahead of print]281 116639
    ATF4-mediated different mode of interaction between autophagy and mTOR determines cell fate dependent on the level of ER stress induced by Cr(VI).
    Xin Zheng, Yuxin Pang, Hasenbilige, Yanqiu Yang, Qiujuan Li, Yong Liu, Jun Cao.
      Hexavalent chromium [Cr(VI)] exists widely in occupational environments. The mechanistic target of rapamycin (mTOR) has been well-documented to regulate autophagy negatively. However, we found that low concentration of Cr(VI) (0.2 μM) elevated both mTOR and autophagy and promote cell survival. Conversely, high concentration of Cr(VI) (6 μM) caused cell death by inhibiting mTOR and subsequently inducing autophagy. Tunicamycin (Tm), as an Endoplasmic reticulum (ER) stress activator was used to induce mild ER stress at 0.1 μg/ml and it activated both autophagy and mTOR, which also caused cell migration in a similar manner to that observed with low concentration of Cr(VI). Severe ER stress caused by Tm (2 μg/ml) decreased mTOR, increased autophagy and then inhibited cell migration, which was the same as 6 μM Cr(VI) treatment, although Cr(VI) in high concentration inhibited ER stress. Activating transcription factor 4 (ATF4), a downstream target of ER stress, only increased under mild ER stress but decreased under severe ER stress and 6 μM Cr(VI) treatment. Chromatin immunoprecipitation (ChIP) experiment indicated that ATF4 could bind to the promoter of ATG4B and AKT1. To sum up, our data revealed that mild ER stress induced by low concentration of Cr(VI) could enhance transcriptional regulation of ATG4B and AKT1 by ATF4, which induced both autophagy and mTOR to promote cell viability.
    Keywords:  ATF4; Autophagy; Chromium; ER stress; mTOR
    DOI:  https://doi.org/10.1016/j.ecoenv.2024.116639
  18. iScience. 2024 Jun 21. 27(6): 110149
    Hyperactive mTORC1 disrupts habenula function and light preference in zebrafish model of Tuberous sclerosis complex.
    Olga Doszyn, Magdalena Kedra, Justyna Zmorzynska.
      Mechanistic target of rapamycin complex 1 (mTORC1) is an integration hub for extracellular and intracellular signals necessary for brain development. Hyperactive mTORC1 is found in autism spectrum disorder (ASD) characterized by atypical reactivity to sensory stimuli, among other symptoms. In Tuberous sclerosis complex (TSC) inactivating mutations in the TSC1 or TSC2 genes result in hyperactivation of the mTORC1 pathway and ASD. Here, we show that lack of light preference of the TSC zebrafish model, tsc2 vu242/vu242 is caused by aberrant processing of light stimuli in the left dorsal habenula and tsc2 vu242/vu242 fish have impaired function of the left dorsal habenula, in which neurons exhibited higher activity and lacked habituation to the light stimuli. These characteristics were rescued by rapamycin. We thus discovered that hyperactive mTorC1 caused aberrant habenula function resulting in lack of light preference. Our results suggest that mTORC1 hyperactivity contributes to atypical reactivity to sensory stimuli in ASD.
    Keywords:  Molecular neuroscience; Neurogenetics; behavioral neuroscience; neuroscience; sensory neuroscience
    DOI:  https://doi.org/10.1016/j.isci.2024.110149
  19. BMC Biol. 2024 Jul 02. 22(1): 146
    Disturbed intracellular folate homeostasis impairs autophagic flux and increases hepatocytic lipid accumulation.
    Wan-Yu Chi, Gang-Hui Lee, Ming-Jer Tang, Bing-Hung Chen, Wei-Ling Lin, Tzu-Fun Fu.
       BACKGROUND: Metabolic associated fatty liver disease (MAFLD), a prevalent liver disorder affecting one-third of the global population, encompasses a spectrum ranging from fatty liver to severe hepatic steatosis. Both genetic and lifestyle factors, particularly diet and nutrition, contribute to its etiology. Folate deficiency, a frequently encountered type of malnutrition, has been associated with the pathogenesis of MAFLD and shown to impact lipid deposition. However, the underlying mechanisms of this relationship remain incompletely understood. We investigated the impact of disturbed folate-mediated one-carbon metabolism (OCM) on hepatic lipid metabolism both in vitro using human hepatoma cells and in vivo using transgenic fluorescent zebrafish displaying extent-, stage-, and duration-controllable folate deficiency upon induction.
    RESULTS: Disturbed folate-mediated one-carbon metabolism, either by inducing folate deficiency or adding anti-folate drug, compromises autophagy and causes lipid accumulation in liver cells. Disturbed folate status down-regulates cathepsin L, a key enzyme involved in autophagy, through inhibiting mTOR signaling. Interfered mitochondrial biology, including mitochondria relocation and increased fusion-fission dynamics, also occurs in folate-deficient hepatocytes. Folate supplementation effectively mitigated the impaired autophagy and lipid accumulation caused by the inhibition of cathepsin L activity, even when the inhibition was not directly related to folate deficiency.
    CONCLUSIONS: Disruption of folate-mediated OCM diminishes cathepsin L expression and impedes autophagy via mTOR signaling, leading to lipid accumulation within hepatocytes. These findings underscore the crucial role of folate in modulating autophagic processes and regulating lipid metabolism in the liver.
    Keywords:  Autophagy; Cathepsin L; Folate deficiency; Lipid metabolism
    DOI:  https://doi.org/10.1186/s12915-024-01946-6
  20. J Toxicol Sci. 2024 ;49(7): 313-319
    Dihydropyrazine induces endoplasmic reticulum stress and inhibits autophagy in HepG2 human hepatoma cells.
    Shinji Takechi, Madoka Sawai, Yuu Miyauchi.
      Dihydropyrazines (DHPs) are formed by non-enzymatic glycation reactions in vivo and in food. We recently reported that 3-hydro-2,2,5,6-tetramethylpyrazine (DHP-3), which is a methyl-substituted DHP, caused severe oxidative stress and cytotoxicity. However, the molecular mechanisms underlying the cytotoxic pathways of the DHP response remain elusive. Because oxidative stress induces endoplasmic reticulum (ER) stress and autophagy, we investigated the ability of DHP-3 to modulate the ER stress and autophagy pathways. DHP-3 activated the ER stress pathway by increasing inositol-requiring enzyme 1 (IRE1) and PKR-like ER kinase (PERK) phosphorylation and transcription factor 6 (ATF6) expression. Moreover, DHP-3 increased the expression of activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP), which are downstream targets of PERK. In addition, DHP-3 inhibited the autophagy pathway by increasing the accumulation of microtubule-associated protein 1 light chain 3 alpha-phosphatidylethanolamine conjugate (LC3-II) and p62/sequestosome 1 (p62), while decreasing autophagic flux. Taken together, these results indicate that DHP-3 activates the ER stress pathway and inhibits the autophagy pathway, suggesting that the resulting removal of damaged organelles is inadequate.
    Keywords:  Autophagy; Dihydropyrazine; ER stress; Glycation; HepG2 cells
    DOI:  https://doi.org/10.2131/jts.49.313
  21. Stem Cell Reports. 2024 Jun 18. pii: S2213-6711(24)00155-3. [Epub ahead of print]
    Retinal cells derived from patients with DRAM2-dependent CORD21 dystrophy exhibit key lysosomal enzyme deficiency and lysosomal content accumulation.
    Rozaliya Tsikandelova, Eldo Galo, Edvinas Cerniauskas, Dean Hallam, Maria Georgiou, Rodrigo Cerna-Chavez, Robert Atkinson, Pavel Palmowski, Florence Burté, Tracey Davies, David H Steel, Martin McKibbin, Jacquelyn Bond, Jennifer Haggarty, Phil Whitfield, Viktor Korolchuk, Lyle Armstrong, Chunbo Yang, Birthe Dorgau, Marzena Kurzawa-Akanbi, Majlinda Lako.
      Biallelic mutations in DRAM2 lead to an autosomal recessive cone-rod dystrophy known as CORD21, which typically presents between the third and sixth decades of life. Although DRAM2 localizes to the lysosomes of photoreceptor and retinal pigment epithelium (RPE) cells, its specific role in retinal degeneration has not been fully elucidated. In this study, we generated and characterized retinal organoids (ROs) and RPE cells from induced pluripotent stem cells (iPSCs) derived from two CORD21 patients. Our investigation revealed that CORD21-ROs and RPE cells exhibit abnormalities in lipid metabolism, defects in autophagic flux, accumulation of aberrant lysosomal content, and reduced lysosomal enzyme activity. We identified potential interactions of DRAM2 with vesicular trafficking proteins, suggesting its involvement in this cellular process. These findings collectively suggest that DRAM2 plays a crucial role in maintaining the integrity of photoreceptors and RPE cells by regulating lysosomal function, autophagy, and potentially vesicular trafficking.
    Keywords:  CORD21; DRAM2; RPE cells; autophagy; lipd metabolism; lysosomes; retinal organoids; vesicular transport
    DOI:  https://doi.org/10.1016/j.stemcr.2024.06.002
  22. Asian J Pharm Sci. 2024 Jun;19(3): 100927
    Autophagy and mitophagy as potential therapeutic targets in diabetic heart condition: Harnessing the power of nanotheranostics.
    Sagnik Nag, Oishi Mitra, Bhanu Maturi, Simran Preet Kaur, Ankita Saini, Muskan Nama, Soumik Roy, Souvik Samanta, Leena Chacko, Rohan Dutta, Suresh Babu Sayana, Vetriselvan Subramaniyan, Jasvinder Singh Bhatti, Ramesh Kandimalla.
      Autophagy and mitophagy pose unresolved challenges in understanding the pathology of diabetic heart condition (DHC), which encompasses a complex range of cardiovascular issues linked to diabetes and associated cardiomyopathies. Despite significant progress in reducing mortality rates from cardiovascular diseases (CVDs), heart failure remains a major cause of increased morbidity among diabetic patients. These cellular processes are essential for maintaining cellular balance and removing damaged or dysfunctional components, and their involvement in the development of diabetic heart disease makes them attractive targets for diagnosis and treatment. While a variety of conventional diagnostic and therapeutic strategies are available, DHC continues to present a significant challenge. Point-of-care diagnostics, supported by nanobiosensing techniques, offer a promising alternative for these complex scenarios. Although conventional medications have been widely used in DHC patients, they raise several concerns regarding various physiological aspects. Modern medicine places great emphasis on the application of nanotechnology to target autophagy and mitophagy in DHC, offering a promising approach to deliver drugs beyond the limitations of traditional therapies. This article aims to explore the potential connections between autophagy, mitophagy and DHC, while also discussing the promise of nanotechnology-based theranostic interventions that specifically target these molecular pathways.
    Keywords:  Autophagy; Diabetes; Diabetic heart condition; Mitophagy; Nanomedicine; Nanotheranostics
    DOI:  https://doi.org/10.1016/j.ajps.2024.100927
  23. Res Sq. 2024 Jun 21. pii: rs.3.rs-4421268. [Epub ahead of print]
    The 18S rRNA Methyltransferase DIMT-1 Regulates Lifespan in the Germline Later in Life.
    Eric Greer, M Hafiz Rothi, Joseph Alhaddad, Gautam Sarkar, Wayne Mitchell, Kejun Ying, Nancy Pohl, Roberto Sotomayor, Julia Natale, Scarlett Dellacono, Vadim Gladyshev.
      Ribosome heterogeneity has emerged as an important regulatory control feature for determining which proteins are synthesized, however, the influence of age on ribosome heterogeneity is not fully understood. Whether mRNA transcripts are selectively translated in young versus old cells and whether dysregulation of this process drives organismal aging is unknown. Here we examined the role of ribosomal RNA (rRNA) methylation in maintaining appropriate translation as organisms age. In a directed RNAi screen, we identified the 18S rRNA N6'-dimethyl adenosine (m6,2A) methyltransferase, dimt-1, as a regulator of C. elegans lifespan and stress resistance. Lifespan extension induced by dimt-1 deficiency required a functional germline and was dependent on the known regulator of protein translation, the Rag GTPase, raga-1, which links amino acid sensing to the mechanistic target of rapamycin complex (mTORC)1. Using an auxin-inducible degron tagged version of dimt-1, we demonstrate that DIMT-1 functions in the germline after mid-life to regulate lifespan. We further found that knock-down of dimt-1 leads to selective translation of transcripts important for stress resistance and lifespan regulation in the C. elegans germline in mid-life including the cytochrome P450 daf-9, which synthesizes a steroid that signals from the germline to the soma to regulate lifespan. We found that dimt-1 induced lifespan extension was dependent on the daf-9 signaling pathway. This finding reveals a new layer of proteome dysfunction, beyond protein synthesis and degradation, as an important regulator of aging. Our findings highlight a new role for ribosome heterogeneity, and specific rRNA modifications, in maintaining appropriate translation later in life to promote healthy aging.
    DOI:  https://doi.org/10.21203/rs.3.rs-4421268/v1
  24. Vet Res. 2024 Jun 28. 55(1): 83
    Duck STING mediates antiviral autophagy directing the interferon signaling pathway to inhibit duck plague virus infection.
    Bin Tian, Yanming Tian, Xuetong Wang, Dongjie Cai, Liping Wu, Mingshu Wang, Renyong Jia, Shun Chen, Dekang Zhu, Mafeng Liu, Qiao Yang, Ying Wu, Xinxin Zhao, Shaqiu Zhang, Di Sun, Juan Huang, Xumin Ou, Zhen Wu, Anchun Cheng.
      Migratory birds are important vectors for virus transmission, how migratory birds recognize viruses and viruses are sustained in birds is still enigmatic. As an animal model for waterfowl among migratory birds, studying and dissecting the antiviral immunity and viral evasion in duck cells may pave a path to deciphering these puzzles. Here, we studied the mechanism of antiviral autophagy mediated by duck STING in DEF cells. The results collaborated that duck STING could significantly enhance LC3B-II/I turnover, LC3B-EGFP puncta formation, and mCherry/EGFP ratio, indicating that duck STING could induce autophagy. The autophagy induced by duck STING is not affected by shRNA knockdown of ATG5 expression, deletion of the C-terminal tail of STING, or TBK1 inhibitor BX795 treatment, indicating that duck STING activated non-classical selective autophagy is independent of interaction with TBK1, TBK1 phosphorylation, and interferon (IFN) signaling. The STING R235A mutant and Sar1A/B kinase mutant abolished duck STING induced autophagy, suggesting binding with cGAMP and COPII complex mediated transport are the critical prerequisite. Duck STING interacted with LC3B through LIR motifs to induce autophagy, the LIR 4/7 motif mutants of duck STING abolished the interaction with LC3B, and neither activated autophagy nor IFN expression, indicating that duck STING associates with LC3B directed autophagy and dictated innate immunity activation. Finally, we found that duck STING mediated autophagy significantly inhibited duck plague virus (DPV) infection via ubiquitously degraded viral proteins. Our study may shed light on one scenario about the control and evasion of diseases transmitted by migratory birds.
    Keywords:  LC3B; LIR; STING; duck plague virus; selective autophagy
    DOI:  https://doi.org/10.1186/s13567-024-01338-2
  25. Vet Microbiol. 2024 Jun 20. pii: S0378-1135(24)00182-2. [Epub ahead of print]295 110160
    Activation of the NLRP3-CASP-1 inflammasome is restrained by controlling autophagy during Glaesserella parasuis infection.
    Chaoxiong Yue, Jinquan Li, Siming Zhang, Ruyi Ma, Mingjiao Suo, Yiwen Chen, Hui Jin, Yan Zeng, Yushan Chen.
      Infection with Glaesserella parasuis, the primary pathogen behind Glässer's disease, is often associated with diverse clinical symptoms, including serofibrinous polyserositis, arthritis, and meningitis. Autophagy plays a dual role in bacterial infections, exerting either antagonistic or synergistic effects depending on the nature of the pathogen. Our previous studies have demonstrated that autophagy serves as a defense mechanism, combating inflammation and invasion caused by infection of highly virulent G. parasuis. However, the precise mechanisms remain to be elucidated. Pathogens exhibit distinct interactions with inflammasomes and autophagy processes. Herein, we explored the effect of autophagy on inflammasomes during G. parasuis infection. We found that G. parasuis infection triggers NLRP3-dependent pro-CASP-1-IL-18/IL-1β processing and maturation pathway, resulting in increased release of IL-1β and IL-18. Inhibition of autophagy enhances NLRP3 inflammasome activity, whereas stimulation of autophagy restricts it during G. parasuis infection. Furthermore, assembled NLRP3 inflammasomes undergo ubiquitination and recruit the autophagic adaptor, p62, facilitating their sequestration into autophagosomes during G. parasuis infection. These results suggest that the induction of autophagy mitigates inflammation by eliminating overactive NLRP3 inflammasomes during G. parasuis infection. Our research uncovers a mechanism whereby G. parasuis infection initiates inflammatory responses by promoting the assembly of the NLRP3 inflammasomes and activating NLRP3-CASP-1, both of which processes are downregulated by autophagy. This suggests that pharmacological manipulation of autophagy could be a promising approach to modulate G. parasuis-induced inflammatory responses.
    Keywords:  Autophagy; CASP-1; Glaesserella parasuis; Inflammasome; NLRP3
    DOI:  https://doi.org/10.1016/j.vetmic.2024.110160
  26. Cell Signal. 2024 Jun 29. pii: S0898-6568(24)00241-9. [Epub ahead of print] 111273
    Lysosomal dysfunction-derived autophagy impairment of gingival epithelial cells in diabetes-associated periodontitis with altered protein acetylation.
    Hui Liu, Zhuo Xie, Xianling Gao, Linhesheng Wei, Mengdi Li, Zhengmei Lin, Xin Huang.
      Diabetes-associated periodontitis (DP) presents severe inflammation and resistance to periodontal conventional treatment, presenting a significant challenge in clinical management. In this study, we investigated the underlying mechanism driving the hyperinflammatory response in gingival epithelial cells (GECs) of DP patients. Our findings indicate that lysosomal dysfunction under high glucose conditions leads to the blockage of autophagy flux, exacerbating inflammatory response in GECs. Single-cell RNA sequencing and immunohistochemistry analyses of clinical gingival epithelia revealed dysregulation in the lysosome pathway characterized by reduced levels of lysosome-associated membrane glycoprotein 2 (LAMP2) and V-type proton ATPase 16 kDa proteolipid subunit c (ATP6V0C) in subjects with DP. In vitro stimulation of human gingival epithelial cells (HGECs) with a hyperglycemic microenvironment showed elevated release of proinflammatory cytokines, compromised lysosomal acidity and blocked autophagy. Moreover, HGECs with deficiency in ATP6V0C demonstrated impaired autophagy and heightened inflammatory response, mirroring the effects of high glucose stimulation. Proteomic analysis of acetylation modifications identified altered acetylation levels in 28 autophagy-lysosome pathway-related proteins and 37 sites in HGECs subjected to high glucose stimulation or siATP6V0C. Overall, our finding highlights the pivotal role of lysosome impairment in autophagy obstruction in DP and suggests a potential impact of altered acetylation of relevant proteins on the interplay between lysosome dysfunction and autophagy blockage. These insights may pave the way for the development of effective therapeutic strategies against DP.
    Keywords:  ATP6V0C; Autophagy; Diabetes-associated periodontitis; Gingival epithelial barrier; Lysosome; Protein acetylation
    DOI:  https://doi.org/10.1016/j.cellsig.2024.111273
  27. Phytother Res. 2024 Jul 03.
    Phytochemical-mediated modulation of autophagy and endoplasmic reticulum stress as a cancer therapeutic approach.
    Mazoun Al Azzani, Zohra Nausheen Nizami, Rym Magramane, Mohammed N Sekkal, Ali H Eid, Yusra Al Dhaheri, Rabah Iratni.
      Autophagy and endoplasmic reticulum (ER) stress are conserved processes that generally promote survival, but can induce cell death when physiological thresholds are crossed. The pro-survival aspects of these processes are exploited by cancer cells for tumor development and progression. Therefore, anticancer drugs targeting autophagy or ER stress to induce cell death and/or block the pro-survival aspects are being investigated extensively. Consistently, several phytochemicals have been reported to exert their anticancer effects by modulating autophagy and/or ER stress. Various phytochemicals (e.g., celastrol, curcumin, emodin, resveratrol, among others) activate the unfolded protein response to induce ER stress-mediated apoptosis through different pathways. Similarly, various phytochemicals induce autophagy through different mechanisms (namely mechanistic target of Rapamycin [mTOR] inhibition). However, phytochemical-induced autophagy can function either as a cytoprotective mechanism or as programmed cell death type II. Interestingly, at times, the same phytochemical (e.g., 6-gingerol, emodin, shikonin, among others) can induce cytoprotective autophagy or programmed cell death type II depending on cellular contexts, such as cancer type. Although there is well-documented mechanistic interplay between autophagy and ER stress, only a one-way modulation was noted with some phytochemicals (carnosol, capsaicin, cryptotanshinone, guangsangon E, kaempferol, and δ-tocotrienol): ER stress-dependent autophagy. Plant extracts are sources of potent phytochemicals and while numerous phytochemicals have been investigated in preclinical and clinical studies, the search for novel phytochemicals with anticancer effects is ongoing from plant extracts used in traditional medicine (e.g., Origanum majorana). Nonetheless, the clinical translation of phytochemicals, a promising avenue for cancer therapeutics, is hindered by several limitations that need to be addressed in future studies.
    Keywords:  ER stress; anticancer drugs; autophagy; phytochemicals; plant extracts; unfolded protein response
    DOI:  https://doi.org/10.1002/ptr.8283
  28. Inflammation. 2024 Jun 29.
    Autophagy Regulation Attenuates Neuroinflammation and Cognitive Decline in an Alzheimer's Disease Mouse Model with Chronic Cerebral Hypoperfusion.
    Qin Yang, Chengmin Yang, Hui Lv, Xingwu Zheng, Sanyin Mao, Ning Liu, Shenglong Mo, Bao Liao, Meiling Yang, Zhicheng Lu, Lina Tang, Xiaorui Huang, Chongdong Jian, Jingwei Shang.
      This study investigates the role of autophagy regulation in modulating neuroinflammation and cognitive function in an Alzheimer's disease (AD) mouse model with chronic cerebral hypoperfusion (CCH). Using the APP23/PS1 mice plus CCH model, we examined the impact of autophagy regulation on cognitive function, neuroinflammation, and autophagic activity. Our results demonstrate significant cognitive impairments in AD mice, exacerbated by CCH, but mitigated by treatment with the autophagy inhibitor 3-methyladenine (3-MA). Dysregulation of autophagy-related proteins, accentuated by CCH, underscores the intricate relationship between cerebral blood flow and autophagy dysfunction in AD pathology. While 3-MA restored autophagic balance, rapamycin (RAPA) treatment did not induce significant changes, suggesting alternative therapeutic approaches are necessary. Dysregulated microglial polarization and neuroinflammation in AD+CCH were linked to cognitive decline, with 3-MA attenuating neuroinflammation. Furthermore, alterations in M2 microglial polarization and the levels of inflammatory markers NLRP3 and MCP1 were observed, with 3-MA treatment exhibiting potential anti-inflammatory effects. Our findings shed light on the crosstalk between autophagy and neuroinflammation in AD+CCH and suggest targeting autophagy as a promising strategy for mitigating neuroinflammation and cognitive decline in AD+CCH.
    Keywords:  Alzheimer's disease; autophagy regulation; chronic cerebral hypoperfusion; cognitive decline; neuroinflammation
    DOI:  https://doi.org/10.1007/s10753-024-02043-0
  29. Microbes Infect. 2024 Jun 29. pii: S1286-4579(24)00121-7. [Epub ahead of print] 105385
    Trypanosoma cruzi Vps34 colocalizes with Beclin1 and plays a role in parasite invasion of the host cell by modulating the expression of a sub-group of trans-sialidases.
    Carlos Alcides Nájera, Mercedes Soares-Silva, Fernando Y Maeda, Wanderson Duarte DaRocha, Isabela Meneghelli, Ana Clara Mendes, Marina Ferreira Batista, Claudio Vieira Silva, José Franco da Silveira, Cristina M Orikaza, Nobuko Yoshida, Viviane Grazielle Silva, Santuza Maria Ribeiro Teixeira, Daniella Castanheira Bartholomeu, Diana Bahia.
      Trypanosoma cruzi, the etiological agent of Chagas' disease, can infect both phagocytic and non-phagocytic cells. T. cruzi gp82 and gp90 are cell surface proteins belonging to Group II trans-sialidases known to be involved in host cell binding and invasion. Phosphatidylinositol kinases (PIK) are lipid kinases that phosphorylate phospholipids in their substrates or in themselves, regulating important cellular functions such as metabolism, cell cycle and survival. Vps34, a class III PIK, regulates autophagy, trimeric G-protein signaling, and the mTOR (mammalian Target of Rapamycin) nutrient-sensing pathway. The mammalian autophagy gene Beclin1 interacts to Vps34 forming Beclin 1-Vps34 complexes involved in autophagy and protein sorting. In T. cruzi epimastigotes, (a non-infective replicative form), TcVps34 has been related to morphological and functional changes associated to vesicular trafficking, osmoregulation and receptor-mediated endocytosis. We aimed to characterize the role of TcVps34 during invasion of HeLa cells by metacyclic (MT) forms. MTs overexpressing TcVps34 showed lower invasion rates compared to controls, whilst exhibiting a significant decrease in gp82 expression in the parasite surface. In addition, we showed that T. cruzi Beclin (TcBeclin1) colocalizes with TcVps34 in epimastigotes, thus suggesting the formation of complexes that may play conserved cellular roles already described for other eukaryotes.
    Keywords:  Beclin1; Group II Trans-sialidases; Trypanosoma cruzi; Vps34; cellular invasion; gp82 and gp90; phosphatidylinositol kinases (PIKs)
    DOI:  https://doi.org/10.1016/j.micinf.2024.105385
  30. Autophagy. 2024 Jul 04.
    FOXO-regulated DEAF1 controls muscle regeneration through autophagy.
    Kah Yong Goh, Wen Xing Lee, Sze Mun Choy, Gopal Krishnan Priyadarshini, Kenon Chua, Qian Hui Tan, Shin Yi Low, Hui San Chin, Chee Seng Wong, Shu-Yi Huang, Nai Yang Fu, Jun Nishiyama, Nathan Harmston, Hong-Wen Tang.
      The commonality between various muscle diseases is the loss of muscle mass, function, and regeneration, which severely restricts mobility and impairs the quality of life. With muscle stem cells (MuSCs) playing a key role in facilitating muscle repair, targeting regulators of muscle regeneration has been shown to be a promising therapeutic approach to repair muscles. However, the underlying molecular mechanisms driving muscle regeneration are complex and poorly understood. Here, we identified a new regulator of muscle regeneration, Deaf1 (Deformed epidermal autoregulatory factor-1) - a transcriptional factor downstream of foxo signaling. We showed that Deaf1 is transcriptionally repressed by FOXOs and that DEAF1 targets to Pik3c3 and Atg16l1 promoter regions and suppresses their expression. Deaf1 depletion therefore induces macroautophagy/autophagy, which in turn blocks MuSC survival and differentiation. In contrast, Deaf1 overexpression inactivates autophagy in MuSCs, leading to increased protein aggregation and cell death. The fact that Deaf1 depletion and its overexpression both lead to defects in muscle regeneration highlights the importance of fine tuning DEAF1-regulated autophagy during muscle regeneration. We further showed that Deaf1 expression is altered in aging and cachectic MuSCs. Manipulation of Deaf1 expression can attenuate muscle atrophy and restore muscle regeneration in aged mice or mice with cachectic cancers. Together, our findings unveil an evolutionarily conserved role for DEAF1 in muscle regeneration, providing insights into the development of new therapeutic strategies against muscle atrophy.
    Keywords:  Autophagy; Deaf1; FOXO; cancer cachexia; muscle; sarcopenia
    DOI:  https://doi.org/10.1080/15548627.2024.2374693
  31. Oncol Rep. 2024 Sep;pii: 112. [Epub ahead of print]52(3):
    Mitochondrial‑associated endoplasmic reticulum membrane interference in ovarian cancer (Review).
    Yi-Fan Dong, Jiaheng Zhang, Jin-Hong Zhou, Yi-Li Xiao, Wan-Juan Pei, Hui-Ping Liu.
      The mitochondria‑associated endoplasmic reticulum (ER) membrane (MAM), serving as a vital link between the mitochondria and ER, holds a pivotal role in maintaining the physiological function of these two organelles. Its specific functions encompass the participation in the biosynthesis and functional regulation of the mitochondria, calcium ion transport, lipid metabolism, oxidative stress and autophagy among numerous other facets. Scientific exploration has revealed that MAMs hold potential as effective therapeutic targets influencing the mitochondria and ER within the context of cancer therapy. The present review focused on elucidating the related pathways of mitochondrial autophagy and ER stress and their practical application in ovarian cancer, aiming to identify commonalities existing between MAMs and these pathways, thereby extending to related applications of MAMs in ovarian cancer treatment. This endeavor aimed at exploring new potential for MAMs in clinically managing ovarian cancer.
    Keywords:  endoplasmic reticulum stress; mitochondrial autophagy; mitochondria‑associated membrane; ovarian cancer
    DOI:  https://doi.org/10.3892/or.2024.8771
  32. EMBO J. 2024 Jul 04.
    A hitchhiker's guide to autophagy.
    Susanna Tulli, Sascha Martens.
      
    DOI:  https://doi.org/10.1038/s44318-024-00160-y
  33. Cell Death Dis. 2024 Jul 03. 15(7): 477
    A mitochondrial checkpoint to NF-κB signaling.
    Emma Guilbaud, Lorenzo Galluzzi.
      Mitochondrial dysfunction can elicit multiple inflammatory pathways, especially when apoptotic caspases are inhibited. Such an inflammatory program is negatively regulated by the autophagic disposal of permeabilized mitochondria. Recent data demonstrate that the ubiquitination of mitochondrial proteins is essential for NEMO-driven NF-kB activation downstream of mitochondrial permeabilization.
    DOI:  https://doi.org/10.1038/s41419-024-06868-3
  34. Autophagy. 2024 Jul 04.
    HLH-30/TFEB mediates sexual dimorphism in immunity in caenorhabditis elegans.
    Jooyeon Sohn, Sujeong Kwon, Gee-Yoon Lee, Sieun S Kim, Yujin Lee, Jongsun Lee, Yoonji Jung, Seokjin Ham, Hae-Eun H Park, Sangsoon Park, Seokjun G Ha, Daehan Lee, Seung-Jae V Lee.
      Sexual dimorphism affects various biological functions, including immune responses. However, the mechanisms by which sex alters immunity remain largely unknown. Using Caenorhabditis elegans as a model species, we showed that males exhibit enhanced immunity against various pathogenic bacteria through the upregulation of HLH-30 (Helix Loop Helix 30/TFEB (transcription factor EB), a transcription factor crucial for macroautophagy/autophagy. Compared with hermaphroditic C. elegans, males displayed increased activity of HLH-30/TFEB, which contributed to enhanced antibacterial immunity. atg-2 (AuTophaGy (yeast Atg homolog) 2) upregulated by HLH-30/TFEB mediated increased immunity in male C. elegans. Thus, the males appear to be equipped with enhanced HLH-30/TFEB-mediated autophagy, which increases pathogen resistance, and this may functionally prolong mate-searching ability with reduced risk of infection.
    Keywords:  ATG-2/ATG2; HLH-30/TFEB; autophagy; caenorhabditis elegans; pathogen resistance; sexual dimorphism
    DOI:  https://doi.org/10.1080/15548627.2024.2375779
  35. Exp Mol Med. 2024 Jul 02.
    The role of BCAA metabolism in metabolic health and disease.
    Byeong Hun Choi, Seunghoon Hyun, Seung-Hoi Koo.
      It has long been postulated that dietary restriction is beneficial for ensuring longevity and extending the health span of mammals, including humans. In particular, a reduction in protein consumption has been shown to be specifically linked to the beneficial effect of dietary restriction on metabolic disorders, presumably by reducing the activity of the mechanistic target of rapamycin complex (mTORC) 1 and the reciprocal activation of AMP-activated protein kinase (AMPK) and sirtuin pathways. Although it is widely used as a dietary supplement to delay the aging process in humans, recent evidence suggests that branched-chain amino acids (BCAAs) might be a major cause of the deteriorating effect of a protein diet on aging and related disorders. In this review, we delineate the regulation of metabolic pathways for BCAAs at the tissue-specific level and summarize recent findings regarding the role of BCAAs in the control of metabolic health and disease in mammals.
    DOI:  https://doi.org/10.1038/s12276-024-01263-6
  36. Front Endocrinol (Lausanne). 2024 ;15 1439492
    Editorial: Autophagy in endocrine-metabolic diseases associated with aging: Volume II.
    Maria Ines Vaccaro, Vincenzo De Tata, Claudio Daniel Gonzalez.
      
    Keywords:  SIRT1; aging; autophagy; exercise; insulin; metabolic diseases; retinopathy; senescence
    DOI:  https://doi.org/10.3389/fendo.2024.1439492
  37. Front Pharmacol. 2024 ;15 1420643
    Insights into the role of mitophagy in lung cancer: current evidence and perspectives.
    Xin Zhang, Dongzhi Yu, Peng Tang, Fengshou Chen.
      Lung cancer, recognized globally as a leading cause of malignancy-associated morbidity and mortality, is marked by its high prevalence and lethality, garnering extensive attention within the medical community. Mitophagy is a critical cellular process that plays a crucial role in regulating metabolism and ensuring quality control within cells. Its relevance to lung cancer has garnered significant attention among researchers and scientists. Mitophagy's involvement in lung cancer encompasses its initiation, progression, metastatic dissemination and treatment. The regulatory landscape of mitophagy is complex, involving numerous signaling proteins and pathways that may exhibit aberrant alterations or mutations within the tumor environment. In the field of treatment, the regulation of mitophagy is considered key to determining cancer chemotherapy, radiation therapy, other treatment options, and drug resistance. Contemporary investigations are directed towards harnessing mitophagy modulators, both inhibitors and activators, in therapeutic strategies, with an emphasis on achieving specificity to minimize collateral damage to healthy cellular populations. Furthermore, molecular constituents and pathways affiliated with mitophagy, serving as potential biomarkers, offer promising avenues for enhancing diagnostic accuracy, prognostic assessment, and prediction of therapeutic responses in lung cancer. Future endeavors will also involve investigating the impact of mitophagy on the composition and function of immune cells within the tumor microenvironment, aiming to enhance our understanding of how mitophagy modulates the immune response to lung cancer. This review aims to comprehensively overview recent advancements about the role of mitophagy in the tumor genesis, progenesis and metastasis, and the impact of mitophagy on the treatment of lung cancer. We also discussed the future research direction of mitophagy in the field of lung cancer.
    Keywords:  autophagy; lung cancer; mitophagy; progression and metastasis; treatment; tumorigenesis
    DOI:  https://doi.org/10.3389/fphar.2024.1420643
  38. Biomed Pharmacother. 2024 Jul 02. pii: S0753-3322(24)00921-1. [Epub ahead of print]177 117037
    Tanshinone I improves TNBC chemosensitivity by suppressing late-phase autophagy through AKT/p38 MAPK signaling pathway.
    Xinglinzi Tang, Jiaqian Gong, Linlin Ren, Zhiyu Wang, Bowen Yang, Wenzhu Wang, Neng Wang.
      The inhibition of autophagy is a potential therapeutic strategy to improve the chemosensitivity of triple-negative breast cancer (TNBC). In this study, we demonstrated that a natural terpenoid tanshinone I (TAN) enhanced the effectiveness of paclitaxel (PTX), at least in part, through an autophagy-dependent mechanism against TNBC. In vitro validation demonstrated that the combined therapy resulted in a synergistic decrease in the growth of TNBC cells. The chemosensitizing impact of TAN might be attributed to its inhibition of PTX-induced autophagy in the late phase by obstructing the fusion of autophagosomes and lysosomes, rather than by inhibiting lysosomal function. The findings from KEGG pathway analysis and molecular docking suggested that TAN might impact breast cancer chemoresistance primarily through the PI3K-Akt and MAPK signaling pathways. The non-canonical AKT/p38 MAPK signaling was further validated as the primary mechanism responsible for the inhibition of autophagy by TAN. In vivo study showed that the combined administration of TAN and PTX demonstrated a more significant suppression of tumor growth and autophagic activity compared to PTX monotherapy in the MDA-MB-231 xenograft nude mouse model. The safety evaluation of TAN in a zebrafish model, along with in vitro and in vivo validation, provided experimental and pre-clinical data supporting its potential as a natural adjunctive therapy in TNBC. Overall, this study suggests that the combination of TAN with PTX could provide an effective treatment option for advanced breast cancer, and targeting the AKT/p38 MAPK/late-autophagy signaling axis may be a promising approach for developing therapeutic interventions against TNBC.
    Keywords:  AKT/p38 MAPK signaling pathway; Late-phase autophagy; TNBC chemosensitivity; Tanshinone I
    DOI:  https://doi.org/10.1016/j.biopha.2024.117037
  39. Curr Biol. 2024 Jun 26. pii: S0960-9822(24)00757-7. [Epub ahead of print]
    Atg8/LC3 controls systemic nutrient surplus signaling in flies and humans.
    Aditi Madan, Kevin P Kelly, Patrick Bahk, Camille E Sullivan, Michelle E Poling, Ava E Brent, Mroj Alassaf, Julien Dubrulle, Akhila Rajan.
      Organisms experience constant nutritional flux. Mechanisms at the interface of opposing nutritional states-scarcity and surplus-enable organismal energy homeostasis. Contingent on nutritional stores, adipocytes secrete adipokines, such as the fat hormone leptin, to signal nutrient status to the central brain. Increased leptin secretion underlies metabolic dysregulation during common obesity, but the molecular mechanisms regulating leptin secretion from human adipocytes are poorly understood. Here, we report that Atg8/LC3 family proteins, best known for their role in autophagy during nutrient scarcity, play an evolutionarily conserved role during nutrient surplus by promoting adipokine secretion. We show that in a well-fed state, Atg8/LC3 promotes the secretion of the Drosophila functional leptin ortholog unpaired 2 (Upd2) and leptin from human adipocytes. Proteomic analyses reveal that LC3 directs leptin to a secretory pathway in human cells. We identified LC3-dependent extracellular vesicle (EV) loading and secretion (LDELS) as a required step for leptin release, highlighting a unique secretory route adopted by leptin in human adipocytes. In Drosophila, mutations to Upd2's Atg8 interaction motif (AIM) result in constitutive adipokine retention. Atg8-mediated Upd2 retention alters lipid storage and hunger response and rewires the bulk organismal transcriptome in a manner conducive to starvation survival. Thus, Atg8/LC3's bidirectional role in nutrient sensing-conveying nutrient surplus and responding to nutrient deprivation-enables organisms to manage nutrient flux effectively. We posit that decoding how bidirectional molecular switches-such as Atg8/LC3-operate at the nexus of nutritional scarcity and surplus will inform therapeutic strategies to tackle chronic metabolic disorders.
    Keywords:  Upd2; adipokine; autophagy independent; exosomes; leptin; obesity; satiety; starvation resilience; unconventional secretion
    DOI:  https://doi.org/10.1016/j.cub.2024.06.005
  40. Tissue Cell. 2024 Jun 21. pii: S0040-8166(24)00156-3. [Epub ahead of print]89 102455
    Knockdown of NUF2-derived exosomes can inhibit the migration and autophagy of BC cells and improve resistance to doxorubicin.
    Lin Luo, Tong Sha, Hongtao Li.
      Breast cancer (BC) is the most common type of fatal cancer in women. New therapeutic strategies need to be explored to enhance the efficacy of doxorubicin by overcoming the resistance of BC cells. NUF2 is a component of the Ndc80 centromere complex and is a key substance in mediating mitosis and affects the progression of multiple tumors. However, the role as well as mechanisms of NUF2 resistance in BC remain unclear. This study aims to reveal the role of NUF2 in drug resistance in BC. We here revealed that NUF2 was highly expressed in human BC. NUF2 depletion-derived exosomes blocked the growth of BC cells. Further, NUF2 ablation-derived exosomes inhibited autophagy in BC cells. Also, NUF2 ablation-derived exosomes improved doxorubicin resistance in BC cells. Mechanically, NUF2 ablation-derived exosomes blocked PI3K/AKT/mTOR axis in BC cells. In summary, NUF2 ablation-derived exosomes blocked the autophagy of BC cells and improved doxorubicin resistance via mediating PI3K/AKT/mTOR axis.
    Keywords:  Autophagy; Breast cancer (BC); Doxorubicin; NUF2; PI3K/AKT/mTOR
    DOI:  https://doi.org/10.1016/j.tice.2024.102455
  41. J Transl Med. 2024 Jul 03. 22(1): 617
    DKK1 loss promotes endometrial fibrosis via autophagy and exosome-mediated macrophage-to-myofibroblast transition.
    Zhanqin Zhang, Jianguo Hu.
       INTRODUCTION: Intrauterine adhesions (IUA) manifest as endometrial fibrosis, often causing infertility or recurrent miscarriage; however, their pathogenesis remains unclear.
    OBJECTIVES: This study assessed the role of Dickkopf WNT signaling pathway inhibitor 1 (DKK1) and autophagy in endometrial fibrosis, using clinical samples as well as in vitro and in vivo experiments.
    METHODS: Immunohistochemistry, immunofluorescence and western blot were used to determine the localization and expression of DKK1 in endometrium; DKK1 silencing and DKK1 overexpression were used to detect the biological effects of DKK1 silencing or expression in endometrial cells; DKK1 gene knockout mice were used to observe the phenotypes caused by DKK1 gene knockout.
    RESULTS: In patients with IUA, DKK1 and autophagy markers were down-regulated; also, α-SMA and macrophage localization were increased in the endometrium. DKK1 conditional knockout (CKO) mice showed a fibrotic phenotype with decreased autophagy and increased localization of α-SMA and macrophages in the endometrium. In vitro studies showed that DKK1 knockout (KO) suppressed the autophagic flux of endometrial stromal cells. In contrast, ectopic expression of DKK1 showed the opposite phenotype. Mechanistically, we discovered that DKK1 regulates autophagic flux through Wnt/β-catenin and PI3K/AKT/mTOR pathways. Further studies showed that DKK1 KO promoted the secretion of interleukin (IL)-8 in exosomes, thereby promoting macrophage proliferation and metastasis. Also, in DKK1 CKO mice, treatment with autophagy activator rapamycin partially restored the endometrial fibrosis phenotype.
    CONCLUSION: Our findings indicated that DKK1 was a potential diagnostic marker or therapeutic target for IUA.
    Keywords:  DKK1, Autophagy; IL-8; Intrauterine adhesions; Wnt, β-catenin
    DOI:  https://doi.org/10.1186/s12967-024-05402-5
  42. Cell Death Dis. 2024 Jul 02. 15(7): 473
    Macrophage migration inhibitory factor (MIF) suppresses mitophagy through disturbing the protein interaction of PINK1-Parkin in sepsis-associated acute kidney injury.
    Tianlong Li, Jiachen Qu, Chang Hu, Jingjing Pang, Yaoyao Qian, Yiming Li, Zhiyong Peng.
      Damage to renal tubular epithelial cells (RTECs) signaled the onset and progression of sepsis-associated acute kidney injury (SA-AKI). Recent research on mitochondria has revealed that mitophagy plays a crucial physiological role in alleviating injury to RTECs and it is suppressed progressively by the inflammation response in SA-AKI. However, the mechanism by which inflammation influences mitophagy remains poorly understood. We examined how macrophage migration inhibitory factor (MIF), a pro-inflammatory protein, influences the PINK1-Parkin pathway of mitophagy by studying protein-protein interactions when MIF was inhibited or overexpressed. Surprisingly, elevated levels of MIF were found to directly bind to PINK1, disrupting its interaction with Parkin. This interference hindered the recruitment of Parkin to mitochondria and impeded the initiation of mitophagy. Furthermore, this outcome led to significant apoptosis of RTECs, which could, however, be reversed by an MIF inhibitor ISO-1 and/or a new mitophagy activator T0467. These findings highlight the detrimental impact of MIF on renal damage through its disruption of the interaction between PINK1 and Parkin, and the therapeutic potential of ISO-1 and T0467 in mitigating SA-AKI. This study offers a fresh perspective on treating SA-AKI by targeting MIF and mitophagy.
    DOI:  https://doi.org/10.1038/s41419-024-06826-z
  43. bioRxiv. 2024 Jun 20. pii: 2024.06.19.599770. [Epub ahead of print]
    Phagolysosomes break down the membrane of a non-apoptotic corpse independent of macroautophagy.
    Shruti Kolli, Cassidy J Kline, Kimya M Rad, Ann M Wehman.
      Cell corpses must be cleared in an efficient manner to maintain tissue homeostasis and regulate immune responses. Ubiquitin-like Atg8/LC3 family proteins promote the degradation of membranes and internal cargo during both macroautophagy and corpse clearance, raising the question how macroautophagy contributes to corpse clearance. Studying the clearance of non-apoptotic dying polar bodies in Caenorhabditis elegans embryos, we show that the LC3 ortholog LGG-2 is enriched in the polar body phagolysosome independent of membrane association or autophagosome formation. We demonstrate that ATG-16.1 and ATG-16.2, which promote membrane association of lipidated Atg8/LC3 proteins, redundantly promote polar body membrane breakdown in phagolysosomes independent of their role in macroautophagy. We also show that the lipid scramblase ATG-9 is needed for autophagosome formation in early embryos but is dispensable for timely polar body membrane breakdown or protein cargo degradation. These findings demonstrate that macroautophagy is not required to promote polar body degradation, in contrast to recent findings with apoptotic corpse clearance in C. elegans embryos. Determining how membrane association of Atg8/LC3 promotes the breakdown of different types of cell corpses in distinct cell types or metabolic states is likely to give insights into the mechanisms of immunoregulation during normal development, physiology, and disease.
    DOI:  https://doi.org/10.1101/2024.06.19.599770
  44. Redox Biol. 2024 Jun 27. pii: S2213-2317(24)00237-4. [Epub ahead of print]75 103259
    Protein modification and degradation in ferroptosis.
    Yuan Wang, Ding Yan, Jinbao Liu, Daolin Tang, Xin Chen.
      Ferroptosis is a form of iron-related oxidative cell death governed by an integrated redox system, encompassing pro-oxidative proteins and antioxidative proteins. These proteins undergo precise control through diverse post-translational modifications, including ubiquitination, phosphorylation, acetylation, O-GlcNAcylation, SUMOylation, methylation, N-myristoylation, palmitoylation, and oxidative modification. These modifications play pivotal roles in regulating protein stability, activity, localization, and interactions, ultimately influencing both the buildup of iron and lipid peroxidation. In mammalian cells, regulators of ferroptosis typically undergo degradation via two principal pathways: the ubiquitin-proteasome system, which handles the majority of protein degradation, and autophagy, primarily targeting long-lived or aggregated proteins. This comprehensive review aims to summarize recent advances in the post-translational modification and degradation of proteins linked to ferroptosis. It also discusses strategies for modulating ferroptosis through protein modification and degradation systems, providing new insights into potential therapeutic applications for both cancer and non-neoplastic diseases.
    Keywords:  Autophagy; Degradation; Ferroptosis; Modification; Proteasome
    DOI:  https://doi.org/10.1016/j.redox.2024.103259
  45. Vet Res. 2024 Jul 04. 55(1): 84
    TRIM26 facilitates PRV infection through NDP52-mediated autophagic degradation of MAVS.
    Wu Chengyue, Wang Mengdong, Wang Xiaoquan, Chen Yeping, Li Hao, Sun Liumei, Ren Jianle, Zhang Zhendong.
      Pseudorabies virus (PRV) has evolved multiple strategies to evade host antiviral responses to benefit virus replication and establish persistent infection. Recently, tripartite motif 26 (TRIM26), a TRIM family protein, has been shown to be involved in a broad range of biological processes involved in innate immunity, especially in regulating viral infection. Herein, we found that the expression of TRIM26 was significantly induced after PRV infection. Surprisingly, the overexpression of TRIM26 promoted PRV production, while the depletion of this protein inhibited virus replication, suggesting that TRIM26 could positively regulate PRV infection. Further analysis revealed that TRIM26 negatively regulates the innate immune response by targeting the RIG-I-triggered type I interferon signalling pathway. TRIM26 was physically associated with MAVS independent of viral infection and reduced MAVS expression. Mechanistically, we found that NDP52 interacted with both TRIM26 and MAVS and that TRIM26-induced MAVS degradation was almost entirely blocked in NDP52-knockdown cells, demonstrating that TRIM26 degrades MAVS through NDP52-mediated selective autophagy. Our results reveal a novel mechanism by which PRV escapes host antiviral innate immunity and provide insights into the crosstalk among virus infection, autophagy, and the innate immune response.
    Keywords:  MAVS; NDP52; Pseudorabies virus (PRV); TRIM26; autophagy; innate immunity
    DOI:  https://doi.org/10.1186/s13567-024-01336-4
  46. bioRxiv. 2024 Jun 18. pii: 2024.06.17.599400. [Epub ahead of print]
    Extensive location bias of the GPCR-dependent translatome via site-selective activation of mTOR.
    Matthew J Klauer, Caitlin Ad Jagla, Nikoleta G Tsvetanova.
      G protein-coupled receptors (GPCRs) modulate various physiological functions by re-wiring cellular gene expression in response to extracellular signals. Control of gene expression by GPCRs has been studied almost exclusively at the transcriptional level, neglecting an extensive amount of regulation that takes place translationally. Hence, little is known about the nature and mechanisms of gene-specific post-transcriptional regulation downstream of receptor activation. Here, we apply an unbiased multiomics approach to delineate an extensive translational regulatory program initiated by the prototypical beta2-adrenergic receptor (β2-AR) and provide mechanistic insights into how these processes are orchestrated. Using ribosome profiling (Ribo-seq), we identify nearly 120 novel gene targets of adrenergic receptor activity which expression is exclusively regulated at the level of translation. We next show that all translational changes are induced selectively by endosomal β2-ARs. We further report that this proceeds through activation of the mammalian target of rapamycin (mTOR) pathway. Specifically, within the set of translational GPCR targets we discover significant enrichment of genes with 5' terminal oligopyrimidine (TOP) motifs, a gene class classically known to be translationally regulated by mTOR. We then demonstrate that endosomal β2-ARs are required for mTOR activation and subsequent mTOR-dependent TOP mRNA translation. Together, this comprehensive analysis of drug-induced translational regulation establishes a critical role for location-biased GPCR signaling in fine-tuning the cellular protein landscape.
    DOI:  https://doi.org/10.1101/2024.06.17.599400
  47. Mol Cell Biochem. 2024 Jun 29.
    Lysosomal cation channel TRPML1 suppression sensitizes acute myeloid leukemia cells to chemotherapeutics by inhibiting autophagy.
    Meifang Dai, Bingqian Lin, Hao Li, Youming Wang, Miaomiao Wu, Yanan Wei, Wenping Zeng, Lili Qu, Chunlei Cang, Xingbing Wang.
      Despite the implementation of novel therapeutic regimens and extensive research efforts, chemoresistance remains a formidable challenge in the treatment of acute myeloid leukemia (AML). Notably, the involvement of lysosomes in chemoresistance has sparked interest in developing lysosome-targeted therapies to sensitize tumor cells to currently approved chemotherapy or as innovative pharmacological approaches. Moreover, as ion channels on the lysosomal membrane are critical regulators of lysosomal function, they present potential as novel targets for enhancing chemosensitivity. Here, we discovered that the expression of a lysosomal cation channel, namely transient receptor potential mucolipin 1 (TRPML1), was elevated in AML cells. Inhibiting TRPML1 individually does not impact the proliferation and apoptosis of AML cells. Importantly, inhibition of TRPML1 demonstrated the potential to modulate the sensitivity of AML cells to chemotherapeutic agents. Exploration of the underlying mechanisms revealed that suppression of TRPML1 impaired autophagy while concurrently increasing the production of reactive oxygen species (ROS) and ROS-mediated lipid peroxidation (Lipid-ROS) in AML cells. Finally, the knockdown of TRPML1 significantly reduced OCI-AML3 tumor growth following chemotherapy in a mouse model of human leukemia. In summary, targeting TRPML1 represents a promising approach for combination therapy aimed at enhancing chemosensitivity in treating AML.
    Keywords:  Acute myeloid leukemia; Autophagy; Chemosensitivity; Lysosome; TRPML1
    DOI:  https://doi.org/10.1007/s11010-024-05054-5
  48. Methods Mol Biol. 2024 ;2814 55-79
    Assaying Lysosomal Enzyme Activity in Dictyostelium discoideum.
    William D Kim, Adam F DiGiacinto, Robert J Huber.
      Lysosomes are membrane-enclosed organelles that digest intracellular material. They contain more than 50 different enzymes that can degrade a variety of macromolecules including nucleic acids, proteins, polysaccharides, and lipids. In addition to functioning within lysosomes, lysosomal enzymes are also secreted. Alterations in the levels and activities of lysosomal enzymes dysregulates lysosomes, which can lead to the intralysosomal accumulation of biological material and the development of lysosomal storage diseases (LSDs) in humans. Dictyostelium discoideum has a long history of being used to study the trafficking and functions of lysosomal enzymes. More recently, it has been used as a model system to study several LSDs. In this chapter, we outline the methods for assessing the activity of several lysosomal enzymes in D. discoideum (α-galactosidase, β-galactosidase, α-glucosidase, β-glucosidase, β-N-acetylglucosaminidase, α-mannosidase, cathepsin B, cathepsin D, cathepsin F, palmitoyl protein thioesterase 1, and tripeptidyl peptidase 1).
    Keywords:  Cathepsin; Dictyostelium discoideum; Enzyme; Hydrolase; Lysosome; Model system; Thioesterase
    DOI:  https://doi.org/10.1007/978-1-0716-3894-1_4
  49. Talanta. 2024 Jul 03. pii: S0039-9140(24)00885-3. [Epub ahead of print]278 126506
    A lysosomal-targeted and viscosity-ultrasensitive near-infrared fluorescent probe for sensing viscosity in cells and a diabetic mice model.
    Peipei Wang, Siwei Ai, Min Deng, Ying Liu, Yin Liu, Longwei He, Songjiao Li.
      Diabetes, as a metabolic disorder, has been implicated in organ dysfunction, often correlated with aberrant changes in viscosity. Lysosomal viscosity serves as an indicator of the lysosome's condition and activity, as it always varies synchronously with the change of lysosome's positioning, structure, and internal constituents. Diabetes, a condition within the metabolic disease category, has the potential to disrupt organ function due to irregular changes in viscosity. Therefore, early and precise diagnosis of diabetes is crucial for the prevention and management of diabetic conditions. Understanding the correlation between viscosity variations and lysosomal changes in vivo is vitally important for researching associated diseases. In this study, we developed Lyso-V, a near-infrared (NIR) fluorescent probe targeting lysosomes, with ultrasensitivity to viscosity changes. This probe, designed with a donor-π-bridge-acceptor (D-π-A) structure, exhibits a significant increase in NIR fluorescence intensity (approximately 690 times) when responding to viscosity, due to a twisted intramolecular charge transfer (TICT) mechanism. Furthermore, the probe designed specifically for lysosomes, enables the detection of changes in lysosomal viscosity as well as autophagy processes. Notably, through the application of this probe, we have detected an increased viscosity within the pathological model of the diabetic mouse. Moreover, Lyso-V was employed to measure the viscosity in diabetic mice. Owing to the multifaceted nature of the Lyso-V probe, it is anticipated to act as a practical and potent resource for deepening our understanding of the pathophysiological aspects of diabetes and aiding in its early detection.
    Keywords:  Diabetes; Fluorescent probe; Lysosome targeting; Near-infrared; Viscosity
    DOI:  https://doi.org/10.1016/j.talanta.2024.126506
  50. Autophagy. 2024 Jul 02.
    Metabolic stress induces a double-positive feedback loop between AMPK and SQSTM1/p62 conferring dual activation of AMPK and NFE2L2/NRF2 to synergize antioxidant defense.
    Eun-Ji Choi, Hyun-Taek Oh, Seon-Hyeong Lee, Chen-Song Zhang, Mengqi Li, Soo-Youl Kim, Sunghyouk Park, Tong-Shin Chang, Byung-Hoon Lee, Sheng-Cai Lin, Sang-Min Jeon.
      Co-occurring mutations in KEAP1 in STK11/LKB1-mutant NSCLC activate NFE2L2/NRF2 to compensate for the loss of STK11-AMPK activity during metabolic adaptation. Characterizing the regulatory crosstalk between the STK11-AMPK and KEAP1-NFE2L2 pathways during metabolic stress is crucial for understanding the implications of co-occurring mutations. Here, we found that metabolic stress increased the expression and phosphorylation of SQSTM1/p62, which is essential for the activation of NFE2L2 and AMPK, synergizing antioxidant defense and tumor growth. The SQSTM1-driven dual activation of NFE2L2 and AMPK was achieved by inducing macroautophagic/autophagic degradation of KEAP1 and facilitating the AXIN-STK11-AMPK complex formation on the lysosomal membrane, respectively. In contrast, the STK11-AMPK activity was also required for metabolic stress-induced expression and phosphorylation of SQSTM1, suggesting a double-positive feedback loop between AMPK and SQSTM1. Mechanistically, SQSTM1 expression was increased by the PPP2/PP2A-dependent dephosphorylation of TFEB and TFE3, which was induced by the lysosomal deacidification caused by low glucose metabolism and AMPK-dependent proton reduction. Furthermore, SQSTM1 phosphorylation was increased by MAP3K7/TAK1, which was activated by ROS and pH-dependent secretion of lysosomal Ca2+. Importantly, phosphorylation of SQSTM1 at S24 and S226 was critical for the activation of AMPK and NFE2L2. Notably, the effects caused by metabolic stress were abrogated by the protons provided by lactic acid. Collectively, our data reveal a novel double-positive feedback loop between AMPK and SQSTM1 leading to the dual activation of AMPK and NFE2L2, potentially explaining why co-occurring mutations in STK11 and KEAP1 happen and providing promising therapeutic strategies for lung cancer.
    Keywords:  AXIN; KEAP1; STK11/LKB1; lysosomal stress; metabolic stress; oxidative stress
    DOI:  https://doi.org/10.1080/15548627.2024.2374692
  51. Mol Neurobiol. 2024 Jul 02.
    BI1 Activates Autophagy and Mediates TDP43 to Regulate ALS Pathogenesis.
    Yu Wang, Yuxiang Wang, Hanlan Yin, Zixuan Xiao, Zhichao Ren, Xueting Ma, Jingtian Zhang, Xueqi Fu, Fuqiang Zhang, Linlin Zeng.
      Amyotrophic lateral sclerosis (ALS) is the most prevalent motor neuron disease in adults. Currently, there are no known drugs or clinical approaches that have demonstrated efficacy in treating ALS. Mitochondrial function and autophagy have been identified as crucial mechanisms in the development of ALS. While Bax inhibitor 1 (BI1) has been implicated in neurodegenerative diseases, its exact mechanism remains unknown. This study investigates the therapeutic impact of BI1 overexpression on ALS both in vivo and in vitro, revealing its ability to mitigate SOD1G93A-induced apoptosis, nuclear damage, mitochondrial dysfunction, and axonal degeneration of motor neurons. At the same time, BI1 prolongs onset time and lifespan of ALS mice, improves motor function, and alleviates neuronal damage, muscle damage, neuromuscular junction damage among other aspects. The findings indicate that BI1 can inhibit pathological TDP43 morphology and initially stimulate autophagy through interaction with TDP43. This study establishes a solid theoretical foundation for understanding the regulation of autophagy by BI1 and TDP43 while shedding light on the pathogenesis of ALS through their interaction - offering new concepts and targets for clinical implementation and drug development.
    Keywords:  ALS; Apoptosis; Exosome; MAM; Mitochondria; Neurodegenerative disease
    DOI:  https://doi.org/10.1007/s12035-024-04313-2
  52. bioRxiv. 2024 Jun 18. pii: 2024.06.18.599616. [Epub ahead of print]
    The Interplay of Acetylation and Ubiquitination Controls PRMT1 Homeostasis.
    Mohd Altaf Najar, Jenna N Beyer, Callie E W Crawford, George M Burslem.
      PRMT1 plays many important roles in both normal and disease biology, thus understanding it's regulation is crucial. Herein, we report the role of p300-mediated acetylation at K228 in triggering PRMT1 degradation through FBXL17-mediated ubiquitination. Utilizing mass-spectrometry, cellular biochemistry, and genetic code-expansion technologies, we elucidate a crucial mechanism independent of PRMT1 transcript levels. These results underscore the significance of acetylation in governing protein stability and expand our understanding of PRMT1 homeostasis. By detailing the molecular interplay between acetylation and ubiquitination involved in PRMT1 degradation, this work contributes to broader efforts in deciphering post-translational mechanisms that influence protein homeostasis.
    DOI:  https://doi.org/10.1101/2024.06.18.599616
  53. Mol Cell Probes. 2024 Jul 01. pii: S0890-8508(24)00020-3. [Epub ahead of print] 101968
    A Dual-Labeling Molecule for Efficient Drug Discovery of Mitochondrial-Lysosomal Interactions.
    Jinfang Wu, Xiaolei Wang, Xiang Li, Zixuan Zhu, Zhongcheng Cui, Tao Zhang, Weiwei Zou, Guanying Han.
      The close association between organelle interactions, such as mitochondrial-lysosomal interactions, and various diseases, including tumors, remains a challenge for drug discovering and identification. Conventional evaluation methods are often complex and multistep labeling procedures often generate false positives, such as cell damage. To overcome these limitations, we employed a single dual-color reporting molecule called Coupa, which labels mitochondria and lysosomes as blue and red, respectively. This facilitates the evaluation and discovering of drugs targeting mitochondria-lysosome contact (MLC). Using Coupa, we validated the effectiveness of various known antitumor drugs in intervening MLC by assessing their effect on key aspects, such as status, localization, and quantity. This provides evidence for the accuracy and applicability of our dual-color reporting molecule. Notably, we observed that several structural isomers of drugs, including Urolithin (A/B/C), exhibited distinct effects on MLC. In addition, Verteporfin and TEAD were found to induce anti-tumor effects by controlling MLC at the organelle level, suggesting a potential new mechanism of action. Collectively, Coupa offers a novel scientific tool for discovering drugs that target mitochondrial-lysosomal interactions. It not only distinguished the differential effects of structurally similar drugs on the same target, but also reveals new mechanisms underlying the reported antitumor properties of existing drugs. Ultimately, our findings contribute to the advancement of drug discovery and provide valuable insights into the complex interactions between organelles in a disease context.
    Keywords:  drug discovering; lysosome; mitochondria; mitochondrial-lysosomal interaction; sensor
    DOI:  https://doi.org/10.1016/j.mcp.2024.101968
  54. Cell Death Differ. 2024 Jul 04.
    TFEB controls syncytiotrophoblast formation and hormone production in placenta.
    Marcella Cesana, Gennaro Tufano, Francesco Panariello, Nicolina Zampelli, Chiara Soldati, Margherita Mutarelli, Sandro Montefusco, Giuseppina Grieco, Lucia Vittoria Sepe, Barbara Rossi, Edoardo Nusco, Giada Rossignoli, Giorgia Panebianco, Fabrizio Merciai, Emanuela Salviati, Eduardo Maria Sommella, Pietro Campiglia, Graziano Martello, Davide Cacchiarelli, Diego Luis Medina, Andrea Ballabio.
      TFEB, a bHLH-leucine zipper transcription factor belonging to the MiT/TFE family, globally modulates cell metabolism by regulating autophagy and lysosomal functions. Remarkably, loss of TFEB in mice causes embryonic lethality due to severe defects in placentation associated with aberrant vascularization and resulting hypoxia. However, the molecular mechanism underlying this phenotype has remained elusive. By integrating in vivo analyses with multi-omics approaches and functional assays, we have uncovered an unprecedented function for TFEB in promoting the formation of a functional syncytiotrophoblast in the placenta. Our findings demonstrate that constitutive loss of TFEB in knock-out mice is associated with defective formation of the syncytiotrophoblast layer. Indeed, using in vitro models of syncytialization, we demonstrated that TFEB translocates into the nucleus during syncytiotrophoblast formation and binds to the promoters of crucial placental genes, including genes encoding fusogenic proteins (Syncytin-1 and Syncytin-2) and enzymes involved in steroidogenic pathways, such as CYP19A1, the rate-limiting enzyme for the synthesis of 17β-Estradiol (E2). Conversely, TFEB depletion impairs both syncytial fusion and endocrine properties of syncytiotrophoblast, as demonstrated by a significant decrease in the secretion of placental hormones and E2 production. Notably, restoration of TFEB expression resets syncytiotrophoblast identity. Our findings identify that TFEB controls placental development and function by orchestrating both the transcriptional program underlying trophoblast fusion and the acquisition of endocrine function, which are crucial for the bioenergetic requirements of embryonic development.
    DOI:  https://doi.org/10.1038/s41418-024-01337-y
  55. Biomed Pharmacother. 2024 Jul 01. pii: S0753-3322(24)00943-0. [Epub ahead of print]177 117059
    Ruthenium complex containing 1,3-thiazolidine-2-thione inhibits hepatic cancer stem cells by suppressing Akt/mTOR signalling and leading to apoptotic and autophagic cell death.
    Sara P Neves, Larissa M Bomfim, Tetsushi Kataura, Sabrine G Carvalho, Mateus L Nogueira, Rosane B Dias, Ludmila de F Valverde, Clarissa A Gurgel Rocha, Milena B P Soares, Monize M da Silva, Alzir A Batista, Viktor I Korolchuk, Daniel P Bezerra.
      Hepatic cancer is one of the main causes of cancer-related death worldwide. Cancer stem cells (CSCs) are a unique subset of cancer cells that promote tumour growth, maintenance, and therapeutic resistance, leading to recurrence. In the present work, the ability of a ruthenium complex containing 1,3-thiazolidine-2-thione (RCT), with the chemical formula [Ru(tzdt)(bipy)(dppb)]PF6, to inhibit hepatic CSCs was explored in human hepatocellular carcinoma HepG2 cells. RCT exhibited potent cytotoxicity to solid and haematological cancer cell lines and reduced the clonogenic potential, CD133+ and CD44high cell percentages and tumour spheroid growth of HepG2 cells. RCT also inhibited cell motility, as observed in the wound healing assay and transwell cell migration assay. RCT reduced the levels of Akt1, phospho-Akt (Ser473), phospho-Akt (Thr308), phospho-mTOR (Ser2448), and phospho-S6 (Ser235/Ser236) in HepG2 cells, indicating that interfering with Akt/mTOR signalling is a mechanism of action of RCT. The levels of active caspase-3 and cleaved PARP (Asp214) were increased in RCT-treated HepG2 cells, indicating the induction of apoptotic cell death. In addition, RCT modulated the autophagy markers LC3B and p62/SQSTM1 in HepG2 cells and increased mitophagy in a mt-Keima-transfected mouse embryonic fibroblast (MEF) cell model, and RCT-induced cytotoxicity was partially prevented by autophagy inhibitors. Furthermore, mutant Atg5-/- MEFs and PentaKO HeLa cells (human cervical adenocarcinoma with five autophagy receptor knockouts) were less sensitive to RCT cytotoxicity than their parental cell lines, indicating that RCT induces autophagy-mediated cell death. Taken together, these data indicate that RCT is a novel potential anti-liver cancer drug with a suppressive effect on CSCs.
    Keywords:  Apoptosis; Autophagy; HCC; Hepatic cancer stem cells; Mitophagy; Ruthenium complex
    DOI:  https://doi.org/10.1016/j.biopha.2024.117059
  56. Autophagy. 2024 Jul 04.
    Enhancing neuronal reticulophagy: a strategy for combating aging and APP toxicity.
    Wenqing Mou, Yixian Cui.
      Reticulophagy, which directs the endoplasmic reticulum (ER) to the phagophore for sequestration within an autophagosome and subsequent lysosomal degradation via specific receptors, is essential for ER quality control and is implicated in various diseases. This study utilizes Drosophila to establish an in vivo model for reticulophagy. Starvation-induced reticulophagy is detected across multiple tissues in Drosophila. Whole-body upregulation or downregulation of the expression of reticulophagy receptors, atl and Rtnl1, negatively affects fly health. Notably, moderate upregulation of reticulophagy in neuronal tissues by overexpressing these receptors reduces age-related degeneration. In a Drosophila Alzheimer model expressing human APP (amyloid beta precursor protein), reticulophagy is compromised. Correcting reticulophagy by enhancing atl and Rtnl1 expression in the neurons promotes APP degradation, significantly reducing neurodegenerative symptoms. However, overexpression of mutated atl and Rtnl1, which disrupts the interaction of the corresponding proteins with Atg8, does not alleviate these symptoms, emphasizing the importance of receptor functionality. These findings support modulating reticulophagy as a therapeutic strategy for aging and neurodegenerative diseases associated with ER protein accumulation.
    Keywords:  Aging; Rtnl1; amyloid beta precursor protein; atl; receptor; reticulophagy
    DOI:  https://doi.org/10.1080/15548627.2024.2375086
  57. Oncol Res. 2024 ;32(7): 1197-1207
    Trametinib boosts palbociclib's efficacy in breast cancer via autophagy inhibition.
    Anguo Wu, Jiao Yan, Ting Su, Chi Feng, Xin Long, Yiru Pan, Rupei Ye, Tian Xia, Hanan Long, Jianming Wu, Xiuli Xiao.
      Breast cancer, a predominant global health issue, requires ongoing exploration of new therapeutic strategies. Palbociclib (PAL), a well-known cyclin-dependent kinase (CDK) inhibitor, plays a critical role in breast cancer treatment. While its efficacy is recognized, the interplay between PAL and cellular autophagy, particularly in the context of the RAF/MEK/ERK signaling pathway, remains insufficiently explored. This study investigates PAL's inhibitory effects on breast cancer using both in vitro (MCF7 and MDA-MB-468 cells) and in vivo (tumor-bearing nude mice) models. Aimed at elucidating the impact of PAL on autophagic processes and exploring the potential of combining it with trametinib (TRA), an MEK inhibitor, our research seeks to address the challenge of PAL-induced drug resistance. Our findings reveal that PAL significantly decreases the viability of MCF7 and MDA-MB-468 cells and reduces tumor size in mice while showing minimal cytotoxicity in MCF10A cells. However, PAL also induces protective autophagy, potentially leading to drug resistance via the RAF/MEK/ERK pathway activation. Introducing TRA effectively neutralized this autophagy, enhancing PAL's anti-tumor efficacy. A combination of PAL and TRA synergistically reduced cell viability and proliferation, and in vivo studies showed notable tumor size reduction. In conclusion, the PAL and TRA combination emerges as a promising strategy for overcoming PAL-induced resistance, offering a new horizon in breast cancer treatment.
    Keywords:  MCF7; MDA-MB-468; Palbociclib; Protective autophagy; RAF/MEK/ERK; Trametinib
    DOI:  https://doi.org/10.32604/or.2024.046139
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