1. Liver mitochondrial DNA damage and genetic variability of Cytochrome b – a key component of the respirasome – drive the severity of fatty liver disease
- Author
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Silvia Cristina Sookoian, Diego Martin Flichman, Carlos José Pirola, Gustavo Osvaldo Castaño, and Martin Enrique Garaycoechea
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0301 basic medicine ,Medicina Clínica ,030204 cardiovascular system & hematology ,Severity of Illness Index ,Oxidative Phosphorylation ,0302 clinical medicine ,Non-alcoholic Fatty Liver Disease ,purl.org/becyt/ford/3.2 [https] ,Nonalcoholic fatty liver disease ,FIBROSIS ,MT-CYB ,Cytochrome b ,Fatty liver ,NASH ,Cytochromes b ,Middle Aged ,Liver ,8-Hydroxy-2'-Deoxyguanosine ,Disease Progression ,purl.org/becyt/ford/3 [https] ,MITOCHONDRIAL DNA ,Adult ,CIENCIAS MÉDICAS Y DE LA SALUD ,GENETICS ,Glutamic Acid ,Oxidative phosphorylation ,DNA, Mitochondrial ,Glutarates ,03 medical and health sciences ,Internal Medicine ,medicine ,Humans ,Gastroenterología y Hepatología ,Obesity ,TRANSCRIPTOME ,Aged ,Aldehydes ,business.industry ,medicine.disease ,Molecular biology ,Oxidative Stress ,030104 developmental biology ,Coenzyme Q – cytochrome c reductase ,Mutation ,Respirasome ,OXIDATIVE DAMAGE ,Lipid Peroxidation ,Steatohepatitis ,Transcriptome ,business ,Amino Acids, Branched-Chain ,DNA Damage - Abstract
Background and aims: The progression of nonalcoholic fatty liver disease (NAFLD) into severe histological forms (steatohepatitis – NASH) is paralleled by the occurrence of complex molecular processes. Mitochondrial dysfunction is a hallmark feature of advanced disease. Mitochondrially encoded cytochrome B (cytochrome b, MT-CYB), a member of the oxidative phosphorylation system, is a key component of the respirasome supercomplex. Here, we hypothesized that NAFLD severity is associated with liver tissue cytochrome b mutations and damaged mitochondrial DNA (mtDNA). Methods: We included 252 liver specimens of NAFLD patients – in whom histological disease ranged from mild to severe – which were linked to clinical and biochemical information. Tissue molecular explorations included MT-CYB sequencing and analysis of differential mtDNA damage. Profiling of circulating Krebs cycle metabolites and global liver transcriptome was performed in a subsample of patients. Tissue levels of 4-hydroxynonenal – a product of lipid peroxidation and 8-hydroxy-2’-deoxyguanosine, a marker of oxidative damage – were measured. Results: Compared to simple steatosis, NASH is associated with a higher level of MT-CYB variance, 12.1 vs. 15.6 substitutions per 103 bp (P = 5.5e-10). The burden of variants was associated with increased levels of 2-hydroxyglutarate, branched-chain amino acids, and glutamate, and changes in the global liver transcriptome. Liver mtDNA damage was associated with advanced disease and inflammation. NAFLD severity was associated with increased tissue levels of DNA oxidative adducts and lipid peroxyl radicals. Conclusion: NASH is associated with genetic alterations of the liver cellular respirasome, including high cytochrome b variation and mtDNA damage, which may result in broad cellular effects. Fil: Pirola, Carlos José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina Fil: Garaycoechea, Martin Enrique. Gobierno de la Provincia de Buenos Aires. Hospital El Cruce Doctor Nestor Carlos Kirchner. Centro de Medicina Traslacional.; Argentina Fil: Flichman, Diego Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; Argentina Fil: Castaño, Gustavo Osvaldo. Gobierno de la Ciudad de Buenos Aires. Hospital "Dr. Abel Zubizarreta"; Argentina Fil: Sookoian, Silvia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina
- Published
- 2020
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