bims-mitdyn Biomed News
on Mitochondrial dynamics: mechanisms
Issue of 2023–06–04
fourteen papers selected by
Edmond Chan, Queen’s University, School of Medicine
  1. Limiting mitochondrial plasticity by targeting DRP1 induces metabolic reprogramming and reduces breast cancer brain metastases.
  2. Succinyl-CoA ligase ADP-forming subunit beta promotes stress granule assembly to regulate redox and drive cancer metastasis.
  3. The E3 ubiquitin ligase FBXL6 controls the quality of newly synthesized mitochondrial ribosomal proteins.
  4. Lysyl oxidase-like 3 restrains mitochondrial ferroptosis to promote liver cancer chemoresistance by stabilizing dihydroorotate dehydrogenase.
  5. ALDH1L2 regulation of formate, formyl-methionine, and ROS controls cancer cell migration and metastasis.
  6. Effectors enabling adaptation to mitochondrial complex I loss in Hurthle cell carcinoma.
  7. Mitochondrial-encoded complex I impairment induces a targetable dependency on aerobic fermentation in Hurthle cell carcinoma of the thyroid.
  8. Structural basis of purine nucleotide inhibition of human uncoupling protein 1.
  9. Uptake of tumor-derived microparticles induces metabolic reprogramming of macrophages in the early metastatic lung.
  10. The CD73 immune checkpoint promotes tumor cell metabolic fitness.
  11. PINK1-Dependent Mitophagy Inhibits Elevated Ubiquitin Phosphorylation Caused by Mitochondrial Damage.
  12. The deubiquitinase OTUB1 governs lung cancer cell fitness by modulating proteostasis of OXPHOS proteins.
  13. MICU1 controls the sensitivity of the mitochondrial Ca2+ uniporter to activators and inhibitors.
  14. Methods for Monitoring Mitochondrial Biogenesis and Turnover in Cultured Hepatocytes and Mouse Liver Using MitoTimer Reporter Assay.
  1. Nat Cancer. 2023 May 29.
    Limiting mitochondrial plasticity by targeting DRP1 induces metabolic reprogramming and reduces breast cancer brain metastases.
    Pravat Kumar Parida, Mauricio Marquez-Palencia, Suvranil Ghosh, Nitin Khandelwal, Kangsan Kim, Vidhya Nair, Xiao-Zheng Liu, Hieu S Vu, Lauren G Zacharias, Paula I Gonzalez-Ericsson, Melinda E Sanders, Bret C Mobley, Jeffrey G McDonald, Andrew Lemoff, Yan Peng, Cheryl Lewis, Gonçalo Vale, Nils Halberg, Carlos L Arteaga, Ariella B Hanker, Ralph J DeBerardinis, Srinivas Malladi.
      Disseminated tumor cells with metabolic flexibility to utilize available nutrients in distal organs persist, but the precise mechanisms that facilitate metabolic adaptations remain unclear. Here we show fragmented mitochondrial puncta in latent brain metastatic (Lat) cells enable fatty acid oxidation (FAO) to sustain cellular bioenergetics and maintain redox homeostasis. Depleting the enriched dynamin-related protein 1 (DRP1) and limiting mitochondrial plasticity in Lat cells results in increased lipid droplet accumulation, impaired FAO and attenuated metastasis. Likewise, pharmacological inhibition of DRP1 using a small-molecule brain-permeable inhibitor attenuated metastatic burden in preclinical models. In agreement with these findings, increased phospho-DRP1 expression was observed in metachronous brain metastasis compared with patient-matched primary tumors. Overall, our findings reveal the pivotal role of mitochondrial plasticity in supporting the survival of Lat cells and highlight the therapeutic potential of targeting cellular plasticity programs in combination with tumor-specific alterations to prevent metastatic recurrences.
    DOI:  https://doi.org/10.1038/s43018-023-00563-6
  2. Proc Natl Acad Sci U S A. 2023 Jun 06. 120(23): e2217332120
    Succinyl-CoA ligase ADP-forming subunit beta promotes stress granule assembly to regulate redox and drive cancer metastasis.
    Austin C Boese, JiHoon Kang, Jung Seok Hwang, Jaehyun Kim, Kiyoung Eun, Courteney M Malin, Kelly R Magliocca, Chaoyun Pan, Lingtao Jin, Sumin Kang.
      Although recent studies demonstrate active mitochondrial metabolism in cancers, the precise mechanisms through which mitochondrial factors contribute to cancer metastasis remain elusive. Through a customized mitochondrion RNAi screen, we identified succinyl-CoA ligase ADP-forming subunit beta (SUCLA2) as a critical anoikis resistance and metastasis driver in human cancers. Mechanistically, SUCLA2, but not the alpha subunit of its enzyme complex, relocates from mitochondria to the cytosol upon cell detachment where SUCLA2 then binds to and promotes the formation of stress granules. SUCLA2-mediated stress granules facilitate the protein translation of antioxidant enzymes including catalase, which mitigates oxidative stress and renders cancer cells resistant to anoikis. We provide clinical evidence that SUCLA2 expression correlates with catalase levels as well as metastatic potential in lung and breast cancer patients. These findings not only implicate SUCLA2 as an anticancer target, but also provide insight into a unique, noncanonical function of SUCLA2 that cancer cells co-opt to metastasize.
    Keywords:  mitochondrial metabolism; redox homeostasis; stress granule; succinyl-CoA ligase; tumor metastasis
    DOI:  https://doi.org/10.1073/pnas.2217332120
  3. Cell Rep. 2023 May 31. pii: S2211-1247(23)00590-9. [Epub ahead of print]42(6): 112579
    The E3 ubiquitin ligase FBXL6 controls the quality of newly synthesized mitochondrial ribosomal proteins.
    Julie Lavie, Claude Lalou, Walid Mahfouf, Jean-William Dupuy, Aurélie Lacaule, Agata Ars Cywinska, Didier Lacombe, Anne-Marie Duchêne, Anne-Aurélie Raymond, Hamid Reza Rezvani, Richard Patryk Ngondo, Giovanni Bénard.
      In mammals, about 99% of mitochondrial proteins are synthesized in the cytosol as precursors that are subsequently imported into the organelle. The mitochondrial health and functions rely on an accurate quality control of these imported proteins. Here, we show that the E3 ubiquitin ligase F box/leucine-rich-repeat protein 6 (FBXL6) regulates the quality of cytosolically translated mitochondrial proteins. Indeed, we found that FBXL6 substrates are newly synthesized mitochondrial ribosomal proteins. This E3 binds to chaperones involved in the folding and trafficking of newly synthesized peptide and to ribosomal-associated quality control proteins. Deletion of these interacting partners is sufficient to hamper interactions between FBXL6 and its substrate. Furthermore, we show that cells lacking FBXL6 fail to degrade specifically mistranslated mitochondrial ribosomal proteins. Finally, showing the role of FBXL6-dependent mechanism, FBXL6-knockout (KO) cells display mitochondrial ribosomal protein aggregations, altered mitochondrial metabolism, and inhibited cell cycle in oxidative conditions.
    Keywords:  CP: Cell biology; F box leucin-rich repeat E3 ubiquitin ligase; FBXL6; mitochondria; protein quality control; ribosomal proteins
    DOI:  https://doi.org/10.1016/j.celrep.2023.112579
  4. Nat Commun. 2023 May 30. 14(1): 3123
    Lysyl oxidase-like 3 restrains mitochondrial ferroptosis to promote liver cancer chemoresistance by stabilizing dihydroorotate dehydrogenase.
    Meixiao Zhan, Yufeng Ding, Shanzhou Huang, Yuhang Liu, Jing Xiao, Hua Yu, Ligong Lu, Xiongjun Wang.
      To overcome chemotherapy resistance, novel strategies sensitizing cancer cells to chemotherapy are required. Here, we screen the lysyl-oxidase (LOX) family to clarify its contribution to chemotherapy resistance in liver cancer. LOXL3 depletion significantly sensitizes liver cancer cells to Oxaliplatin by inducing ferroptosis. Chemotherapy-activated EGFR signaling drives LOXL3 to interact with TOM20, causing it to be hijacked into mitochondria, where LOXL3 lysyl-oxidase activity is reinforced by phosphorylation at S704. Metabolic adenylate kinase 2 (AK2) directly phosphorylates LOXL3-S704. Phosphorylated LOXL3-S704 targets dihydroorotate dehydrogenase (DHODH) and stabilizes it by preventing its ubiquitin-mediated proteasomal degradation. K344-deubiquitinated DHODH accumulates in mitochondria, in turn inhibiting chemotherapy-induced mitochondrial ferroptosis. CRISPR-Cas9-mediated site-mutation of mouse LOXL3-S704 to D704 causes a reduction in lipid peroxidation. Using an advanced liver cancer mouse model, we further reveal that low-dose Oxaliplatin in combination with the DHODH-inhibitor Leflunomide effectively inhibit liver cancer progression by inducing ferroptosis, with increased chemotherapy sensitivity and decreased chemotherapy toxicity.
    DOI:  https://doi.org/10.1038/s41467-023-38753-6
  5. Cell Rep. 2023 May 26. pii: S2211-1247(23)00573-9. [Epub ahead of print]42(6): 112562
    ALDH1L2 regulation of formate, formyl-methionine, and ROS controls cancer cell migration and metastasis.
    Marc Hennequart, Steven E Pilley, Christiaan F Labuschagne, Jack Coomes, Loic Mervant, Paul C Driscoll, Nathalie M Legrave, Younghwan Lee, Peter Kreuzaler, Benedict Macintyre, Yulia Panina, Julianna Blagih, David Stevenson, Douglas Strathdee, Deborah Schneider-Luftman, Eva Grönroos, Eric C Cheung, Mariia Yuneva, Charles Swanton, Karen H Vousden.
      Mitochondrial 10-formyltetrahydrofolate (10-formyl-THF) is utilized by three mitochondrial enzymes to produce formate for nucleotide synthesis, NADPH for antioxidant defense, and formyl-methionine (fMet) to initiate mitochondrial mRNA translation. One of these enzymes-aldehyde dehydrogenase 1 family member 2 (ALDH1L2)-produces NADPH by catabolizing 10-formyl-THF into CO2 and THF. Using breast cancer cell lines, we show that reduction of ALDH1L2 expression increases ROS levels and the production of both formate and fMet. Both depletion of ALDH1L2 and direct exposure to formate result in enhanced cancer cell migration that is dependent on the expression of the formyl-peptide receptor (FPR). In various tumor models, increased ALDH1L2 expression lowers formate and fMet accumulation and limits metastatic capacity, while human breast cancer samples show a consistent reduction of ALDH1L2 expression in metastases. Together, our data suggest that loss of ALDH1L2 can support metastatic progression by promoting formate and fMet production, resulting in enhanced FPR-dependent signaling.
    Keywords:  ALDH1L2; CP: Cancer; CP: Metabolism; ROS; breast cancer; formate; formyl-methionine; metastasis; one-carbon metabolism; serine
    DOI:  https://doi.org/10.1016/j.celrep.2023.112562
  6. Cancer Discov. 2023 Jun 01. pii: CD-22-0976. [Epub ahead of print]
    Effectors enabling adaptation to mitochondrial complex I loss in Hurthle cell carcinoma.
    Raj K Gopal, Venkata R Vantaku, Apekshya Panda, Bryn Reimer, Sneha Rath, Tsz-Leung To, Adam S Fisch, Murat Cetinbas, Maia Livneh, Michael J Calcaterra, Benjamin J Gigliotti, Kerry A Pierce, Clary B Clish, Dora Dias-Santagata, Peter M Sadow, Lori J Wirth, Gilbert H Daniels, Ruslan I Sadreyev, Sarah E Calvo, Sareh Parangi, Vamsi K Mootha.
      Oncocytic (Hurthle cell) carcinoma of the thyroid (HCC) is genetically characterized by complex I mitochondrial DNA mutations and widespread chromosomal losses. Here, we utilize RNA-seq and metabolomics to identify candidate molecular effectors activated by these genetic drivers. We find glutathione biosynthesis, amino acid metabolism, mitochondrial unfolded protein response, and lipid peroxide scavenging to be increased in HCC. A CRISPR-Cas9 knockout screen in a new HCC model reveals which pathways are key for fitness, and highlights loss of GPX4, a defense against lipid peroxides and ferroptosis, as a strong liability. Rescuing complex I redox activity with the yeast NADH dehydrogenase (NDI1) in HCC cells diminishes ferroptosis sensitivity, while inhibiting complex I in normal thyroid cells augments ferroptosis induction. Our work demonstrates unmitigated lipid peroxide stress to be an HCC vulnerability that is mechanistically coupled to the genetic loss of mitochondrial complex I activity.
    DOI:  https://doi.org/10.1158/2159-8290.CD-22-0976
  7. Cancer Discov. 2023 Jun 01. pii: CD-22-0982. [Epub ahead of print]
    Mitochondrial-encoded complex I impairment induces a targetable dependency on aerobic fermentation in Hurthle cell carcinoma of the thyroid.
    Anderson R Frank, Vicky Li, Spencer D Shelton, Jiwoong Kim, Gordon M Stott, Leonard M Neckers, Yang Xie, Noelle S Williams, Prashant Mishra, David G McFadden.
      A metabolic hallmark of cancer identified by Warburg is the increased consumption of glucose and secretion of lactate, even in the presence of oxygen. Although many tumors exhibit increased glycolytic activity, most forms of cancer rely on mitochondrial respiration for tumor growth. We report here that Hurthle cell carcinoma of the thyroid (HTC) models harboring mitochondrial DNA-encoded defects in complex I of the mitochondrial electron transport chain exhibit impaired respiration and alterations in glucose metabolism. CRISPR-Cas9 pooled screening identified glycolytic enzymes as selectively essential in complex I-mutant HTC cells. We demonstrate in cultured cells and a PDX model that small molecule inhibitors of lactate dehydrogenase selectively induce an ATP crisis and cell death in HTC. This work demonstrates that complex I loss exposes fermentation as a therapeutic target in HTC and has implications for other tumors bearing mutations that irreversibly damage mitochondrial respiration.
    DOI:  https://doi.org/10.1158/2159-8290.CD-22-0982
  8. Sci Adv. 2023 Jun 02. 9(22): eadh4251
    Structural basis of purine nucleotide inhibition of human uncoupling protein 1.
    Scott A Jones, Prerana Gogoi, Jonathan J Ruprecht, Martin S King, Yang Lee, Thomas Zögg, Els Pardon, Deepak Chand, Stefan Steimle, Danielle M Copeman, Camila A Cotrim, Jan Steyaert, Paul G Crichton, Vera Moiseenkova-Bell, Edmund R S Kunji.
      Mitochondrial uncoupling protein 1 (UCP1) gives brown adipose tissue of mammals its specialized ability to burn calories as heat for thermoregulation. When activated by fatty acids, UCP1 catalyzes the leak of protons across the mitochondrial inner membrane, short-circuiting the mitochondrion to generate heat, bypassing ATP synthesis. In contrast, purine nucleotides bind and inhibit UCP1, regulating proton leak by a molecular mechanism that is unclear. We present the cryo-electron microscopy structure of the GTP-inhibited state of UCP1, which is consistent with its nonconducting state. The purine nucleotide cross-links the transmembrane helices of UCP1 with an extensive interaction network. Our results provide a structural basis for understanding the specificity and pH dependency of the regulatory mechanism. UCP1 has retained all of the key functional and structural features required for a mitochondrial carrier-like transport mechanism. The analysis shows that inhibitor binding prevents the conformational changes that UCP1 uses to facilitate proton leak.
    DOI:  https://doi.org/10.1126/sciadv.adh4251
  9. Cell Rep. 2023 May 30. pii: S2211-1247(23)00593-4. [Epub ahead of print]42(6): 112582
    Uptake of tumor-derived microparticles induces metabolic reprogramming of macrophages in the early metastatic lung.
    Kelly Kersten, Ran You, Sophia Liang, Kevin M Tharp, Joshua Pollack, Valerie M Weaver, Matthew F Krummel, Mark B Headley.
      Pre-metastatic niche formation is a critical step during the metastatic spread of cancer. One way by which primary tumors prime host cells at future metastatic sites is through the shedding of tumor-derived microparticles as a consequence of vascular sheer flow. However, it remains unclear how the uptake of such particles by resident immune cells affects their phenotype and function. Here, we show that ingestion of tumor-derived microparticles by macrophages induces a rapid metabolic and phenotypic switch that is characterized by enhanced mitochondrial mass and function, increased oxidative phosphorylation, and upregulation of adhesion molecules, resulting in reduced motility in the early metastatic lung. This reprogramming event is dependent on signaling through the mTORC1, but not the mTORC2, pathway and is induced by uptake of tumor-derived microparticles. Together, these data support a mechanism by which uptake of tumor-derived microparticles induces reprogramming of macrophages to shape their fate and function in the early metastatic lung.
    Keywords:  CP: Cancer; CP: Metabolism; infinity flow; lung; macrophages; metastasis
    DOI:  https://doi.org/10.1016/j.celrep.2023.112582
  10. Elife. 2023 Jun 01. pii: e84508. [Epub ahead of print]12
    The CD73 immune checkpoint promotes tumor cell metabolic fitness.
    David Allard, Isabelle Cousineau, Eric H Ma, Bertrand Allard, Yacine Bareche, Hubert Fleury, John Stagg.
      CD73 is an ectonucleotidase overexpressed on tumor cells that suppresses anti-tumor immunity. Accordingly, several CD73 inhibitors are currently being evaluated in the clinic, including in large randomized clinical trials. Yet, the tumor cell-intrinsic impact of CD73 remain largely uncharacterized. Using metabolomics, we discovered that CD73 significantly enhances tumor cell mitochondrial respiration and aspartate biosynthesis. Importantly, rescuing aspartate biosynthesis was sufficient to restore proliferation of CD73-deficient tumors in immune deficient mice. Seahorse analysis of a large panel of mouse and human tumor cells demonstrated that CD73 enhanced oxidative phosphorylation (OXPHOS) and glycolytic reserve. Targeting CD73 decreased tumor cell metabolic fitness, increased genomic instability and suppressed poly ADP ribose polymerase (PARP) activity. Our study thus uncovered an important immune-independent function for CD73 in promoting tumor cell metabolism, and provides the rationale for previously unforeseen combination therapies incorporating CD73 inhibition.
    Keywords:  cancer biology; human; mouse
    DOI:  https://doi.org/10.7554/eLife.84508
  11. J Med Chem. 2023 May 29.
    PINK1-Dependent Mitophagy Inhibits Elevated Ubiquitin Phosphorylation Caused by Mitochondrial Damage.
    Olivia A Lambourne, Shane Bell, Léa P Wilhelm, Erika B Yarbrough, Gabriel G Holly, Oliver M Russell, Arwa M Alghamdi, Azeza M Fdel, Carmine Varricchio, Emma L Lane, Ian G Ganley, Arwyn T Jones, Matthew S Goldberg, Youcef Mehellou.
      Ubiquitin phosphorylation by the mitochondrial protein kinase PTEN-induced kinase 1 (PINK1), upon mitochondrial depolarization, is an important intermediate step in the recycling of damaged mitochondria via mitophagy. As mutations in PINK1 can cause early-onset Parkinson's disease (PD), there has been a growing interest in small-molecule activators of PINK1-mediated mitophagy as potential PD treatments. Herein, we show that N6-substituted adenosines, such as N6-(2-furanylmethyl)adenosine (known as kinetin riboside) and N6-benzyladenosine, activate PINK1 in HeLa cells and induce PINK1-dependent mitophagy in primary mouse fibroblasts. Interestingly, pre-treatment of HeLa cells and astrocytes with these compounds inhibited elevated ubiquitin phosphorylation that is induced by established mitochondrial depolarizing agents, carbonyl cyanide m-chlorophenyl-hydrazine and niclosamide. Together, this highlights N6-substituted adenosines as progenitor PINK1 activators that could potentially be developed, in the future, as treatments for aged and sporadic PD patients who have elevated phosphorylated ubiquitin levels in the brain.
    DOI:  https://doi.org/10.1021/acs.jmedchem.3c00555
  12. Biochim Biophys Acta Mol Basis Dis. 2023 May 26. pii: S0925-4439(23)00133-3. [Epub ahead of print] 166767
    The deubiquitinase OTUB1 governs lung cancer cell fitness by modulating proteostasis of OXPHOS proteins.
    Aidana Sheryazdanova, Nivea Dias Amoedo, Sara Dufour, Francis Impens, Rodrigue Rossignol, Anna Sablina.
      Aerobic glycolysis is a hallmark of cancer development, but this dogma has been challenged by reports showing a key role of oxidative phosphorylation (OXPHOS) in cancer cell survival. It has been proposed that increased levels of intramitochondrial proteins in cancer cells are associated with high OXPHOS activity and increased sensitivity to OXPHOS inhibitors. However, the molecular mechanisms leading to the high expression of OXPHOS proteins in cancer cells remain unknown. Multiple proteomics studies have detected the ubiquitination of intramitochondrial proteins, suggesting the contribution of the ubiquitin system to the proteostatic regulation of OXPHOS proteins. Here, we identified the ubiquitin hydrolase OTUB1 as a regulator of the mitochondrial metabolic machinery essential for lung cancer cell survival. Mitochondria-localized OTUB1 modulates respiration by inhibiting K48-linked ubiquitination and turnover of OXPHOS proteins. An increase in OTUB1 expression is commonly observed in one-third of non-small-cell lung carcinomas and is associated with high OXPHOS signatures. Moreover, OTUB1 expression highly correlates with the sensitivity of lung cancer cells to mitochondrial inhibitors.
    Keywords:  Lung cancer; Mitochondrial Proteostasis; OTUB1; Oxidative phosphorylation
    DOI:  https://doi.org/10.1016/j.bbadis.2023.166767
  13. Cell Chem Biol. 2023 May 22. pii: S2451-9456(23)00127-7. [Epub ahead of print]
    MICU1 controls the sensitivity of the mitochondrial Ca2+ uniporter to activators and inhibitors.
    Macarena Rodríguez-Prados, Kai-Ting Huang, Katalin Márta, Melanie Paillard, György Csordás, Suresh K Joseph, György Hajnóczky.
      Mitochondrial Ca2+ homeostasis loses its control in many diseases and might provide therapeutic targets. Mitochondrial Ca2+ uptake is mediated by the uniporter channel (mtCU), formed by MCU and is regulated by the Ca2+-sensing gatekeeper, MICU1, which shows tissue-specific stoichiometry. An important gap in knowledge is the molecular mechanism of the mtCU activators and inhibitors. We report that all pharmacological activators of the mtCU (spermine, kaempferol, SB202190) act in a MICU1-dependent manner, likely by binding to MICU1 and preventing MICU1's gatekeeping activity. These agents also sensitized the mtCU to inhibition by Ru265 and enhanced the Mn2+-induced cytotoxicity as previously seen with MICU1 deletion. Thus, MCU gating by MICU1 is the target of mtCU agonists and is a barrier for inhibitors like RuRed/Ru360/Ru265. The varying MICU1:MCU ratios result in different outcomes for both mtCU agonists and antagonists in different tissues, which is relevant for both pre-clinical research and therapeutic efforts.
    Keywords:  MCU; MICU1; Ru265; SB202190; calcium; kaempferol; ruthenium red; spermine
    DOI:  https://doi.org/10.1016/j.chembiol.2023.05.002
  14. Methods Mol Biol. 2023 ;2675 97-107
    Methods for Monitoring Mitochondrial Biogenesis and Turnover in Cultured Hepatocytes and Mouse Liver Using MitoTimer Reporter Assay.
    Xiaowen Ma, Wen-Xing Ding.
      Mitochondrial biogenesis and turnover rate are critical to maintain homeostasis of the intracellular mitochondrial pool. Altered mitochondrial biogenesis and mitophagy are closely related to many chronic diseases, highlighting the importance of mitochondrial stasis in various pathological conditions including liver diseases. We describe a detailed protocol for monitoring mitochondrial lifecycle in primary cultured mouse hepatocytes and mouse liver using the dual color fluorescence-based imaging of MitoTimer. Three types of mitochondria were visualized in mouse hepatocytes: green-only mitochondria (newly synthesized mitochondria), red-only mitochondria (old/aging mitochondria), as well as the majority of yellow mitochondria (representing an intermediate stage of mitochondria). The ratio of red/green fluorescence in each cell will be used to track mitochondrial aging. Super-resolution microscopy analysis revealed that majority of mitochondria were spatially heterogeneous with proteins from simultaneous new synthesis, maturation, and turnover in hepatocytes. MitoTimer reporter assay can specifically target to mitochondria and be used to monitor mitochondrial biogenesis and maturation as well as turnover in vitro and in vivo.
    Keywords:  Hepatocytes; Liver; MitoTimer; Mitophagy; Quality control
    DOI:  https://doi.org/10.1007/978-1-0716-3247-5_8
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