bims-apauto Biomed News
on Apoptosis and autophagy
Issue of 2022‒06‒12
five papers selected by
Su Hyun Lee
Seoul National University

  1. Autophagy. 2022 Jun 05. 1-2
      The protein TRIM5 is under intensive investigation related to its roles in antiviral defense, yet its underlying mechanisms of action remain elusive. In our study, we performed an unbiased identification of TRIM5-interacting partners and found proteins participating in a wide variety of cellular functions. We utilized this proteomics data set to uncover a role for TRIM5 in mitophagy, a mitochondrial quality control system that is impaired in multiple human diseases. Mitochondrial damage triggers the recruitment of TRIM5 to ER-mitochondria contact sites where TRIM5 colocalizes with markers of autophagosome biogenesis. Cells lacking TRIM5 are unable to carry out PRKN-dependent and PRKN-independent mitophagy pathways. TRIM5 knockout cells show reduced mitochondrial function and uncontrolled immune activation in response to mitochondrial damage; phenotypes consistent with a requirement for TRIM5 in mitophagy. Mechanistically, we found that TRIM5 is required for the recruitment of the autophagy initiation machinery to damaged mitochondria, where TRIM5 acts as a scaffold promoting interactions between protein markers of mitochondrial damage and the autophagy initiation machinery.
    Keywords:  APEX2; HIV-1; TRIM5α; autophagy; inflammation; mitochondria; mitophagy; restriction factor; tripartite-motif
  2. Autophagy. 2022 Jun 09. 1-14
      Mitophagy is an essential mitochondrial quality control mechanism that eliminates damaged mitochondria and the production of reactive oxygen species (ROS). The relationship between mitochondria oxidative stress, ROS production and mitophagy are intimately interwoven, and these processes are all involved in various pathological conditions of acute kidney injury (AKI). The elimination of damaged mitochondria through mitophagy in mammals is a complicated process which involves several pathways. Furthermore, the interplay between mitophagy and different types of cell death, such as apoptosis, pyroptosis and ferroptosis in kidney injury is unclear. Here we will review recent advances in our understanding of the relationship between ROS and mitophagy, the different mitophagy pathways, the relationship between mitophagy and cell death, and the relevance of these processes in the pathogenesis of AKI.Abbreviations: AKI: acute kidney injury; AMBRA1: autophagy and beclin 1 regulator 1; ATP: adenosine triphosphate; BAK1: BCL2 antagonist/killer 1; BAX: BCL2 associated X, apoptosis regulator; BCL2: BCL2 apoptosis regulator; BECN1: beclin 1; BH3: BCL2 homology domain 3; BNIP3: BCL2 interacting protein 3; BNIP3L/NIX: BCL2 interacting protein 3 like; CASP1: caspase 1; CAT: catalase; CCCP: carbonyl cyanide m-chlorophenylhydrazone; CI-AKI: contrast-induced acute kidney injury; CISD1: CDGSH iron sulfur domain 1; CL: cardiolipin; CNP: 2',3'-cyclic nucleotide 3'-phosphodiesterase; DNM1L/DRP1: dynamin 1 like; E3: enzyme 3; ETC: electron transport chain; FA: folic acid; FUNDC1: FUN14 domain containing 1; G3P: glycerol-3-phosphate; G6PD: glucose-6-phosphate dehydrogenase; GPX: glutathione peroxidase; GSH: glutathione; GSK3B: glycogen synthase kinase 3 beta; GSR: glutathione-disulfide reductase; HIF1A: hypoxia inducible factor 1 subunit alpha; HUWE1: HECT, UBA and WWE domain containing 1; IL1B: interleukin 1 beta; IMM: inner mitochondrial membrane; IPC: ischemic preconditioning; IRI: ischemia-reperfusion injury; LIR: LC3-interacting region; LPS: lipopolysaccharide; MA: malate-aspartate; MPT: mitochondrial permeability transition; MUL1: mitochondrial E3 ubiquitin protein ligase 1; mtROS: mitochondrial ROS; NLR: NOD-like receptor; NLRP3: NLR family pyrin domain containing 3; NOX: NADPH oxidase; OGD-R: oxygen-glucose deprivation-reperfusion; OMM: outer mitochondrial membrane; OPA1: OPA1 mitochondrial dynamin like GTPase; OXPHOS: oxidative phosphorylation; PARL: presenilin associated rhomboid like; PINK1: PTEN induced kinase 1; PLSCR3: phospholipid scramblase 3; PMP: peptidase, mitochondrial processing; PRDX: peroxiredoxin; PRKN: parkin RBR E3 ubiquitin protein ligase; RPTC: rat proximal tubular cells; ROS: reactive oxygen species; SLC7A11/xCT: solute carrier family 7 member 11; SOD: superoxide dismutase; SOR: superoxide reductase; SQSTM1/p62: sequestosome 1; TCA: tricarboxylic acid; TIMM: translocase of inner mitochondrial membrane; TOMM: translocase of outer mitochondrial membrane; TXN: thioredoxin; VDAC: voltage dependent anion channel; VCP: valosin containing protein.
    Keywords:  Acute kidney injury; cell death; mitochondria; mitophagy; reactive oxygen species
  3. EMBO J. 2022 Jun 07. e109777
      Autophagy represents a fundamental mechanism for maintaining cell survival and tissue homeostasis in response to physiological and pathological stress. Autophagy initiation converges on the FIP200-ATG13-ULK1 complex wherein the serine/threonine kinase ULK1 plays a central role. Here, we reveal that the E3 ubiquitin ligase TRIM27 functions as a negative regulatory component of the FIP200-ATG13-ULK1 complex. TRIM27 directly polyubiquitinates ULK1 at K568 and K571 sites with K48-linked ubiquitin chains, with proteasomal turnover maintaining control over basal ULK1 levels. However, during starvation-induced autophagy, TRIM27 catalyzes non-degradative K6- and K11-linked ubiquitination of the serine/threonine kinase 38-like (STK38L) kinase. In turn, STK38L ubiquitination promotes its activation and phosphorylation of ULK1 at Ser495, rendering ULK1 in a permissive state for TRIM27-mediated hyper-ubiquitination of ULK1. This cooperative mechanism serves to restrain the amplitude and duration of autophagy. Further evidence from mouse models shows that basal autophagy levels are increased in Trim27 knockout mice and that Trim27 differentially regulates tumorigenesis and metastasis. Our study identifies a key role of STK38L-TRIM27-ULK1 signaling axis in negatively controlling autophagy with relevance established in human breast cancer.
    Keywords:  STK38L; TRIM27; ULK1; autophagy; tumorigenesis
  4. Cell Death Dis. 2022 Jun 10. 13(6): 544
      Ferroptosis is a type of cell death that depends on iron and reactive oxygen species (ROS). The accumulation of iron and lipid peroxidation primarily initiates oxidative membrane damage during ferroptosis. The core molecular mechanism of ferroptosis includes the regulation of oxidation and the balance between damage and antioxidant defense. Tumor cells usually contain a large amount of H2O2, and ferrous/iron ions will react with excessive H2O2 in cells to produce hydroxyl radicals and induce ferroptosis in tumor cells. Here, we reviewed the latest studies on the regulation of ferroptosis in tumor cells and introduced the tumor-related signaling pathways of ferroptosis. We paid particular attention to the role of noncoding RNA, nanomaterials, the role of drugs, and targeted treatment using ferroptosis drugs for mediating the ferroptosis process in tumor cells. Finally, we discussed the currently unresolved problems and future research directions for ferroptosis in tumor cells and the prospects of this emerging field. Therefore, we have attempted to provide a reference for further understanding of the pathogenesis of ferroptosis and proposed new targets for cancer treatment.
  5. ACS Appl Mater Interfaces. 2022 Jun 08.
      Ferroptosis-apoptosis, a new modality of induced cell death dependent on reactive oxygen species, has drawn tremendous attention in the field of nanomedicine. A metal-free ferroptosis-apoptosis inducer was reported based on boron and nitrogen codoped graphdiyne (BN-GDY) that possesses efficient glutathione (GSH) depletion capability and concurrently induces ferroptosis by deactivation of GSH-dependent peroxidases 4 (GPX4) and apoptosis by downregulation of Bcl2. The high catalytic activity of BN-GDY is explicated by both kinetic experiments and density functional theory (DFT) calculations of Gibbs free energy change during hydrogen peroxide (H2O2) decomposition. In addition, a unique sequence Bi-Bi mechanism is discovered, which is distinct from the commonly reported ping-pong Bi-Bi mechanism of most peroxidase mimics and natural enzymes. We anticipate that this nonmetal ferroptosis-apoptosis therapeutic concept by carbon-based nanomaterials would provide proof-of-concept evidence for nanocatalytic medicines in cancer therapy.
    Keywords:  colon cancer; ferroptosis−apoptosis; graphdiyne; metal-free; nanozyme