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Mitochondrion ; 61: 147-158, 2021 11.
Article in English | MEDLINE | ID: covidwho-1500157


The COVID-19 pandemic prompted the FDA to authorize a new nucleoside analogue, remdesivir, for emergency use in affected individuals. We examined the effects of its active metabolite, remdesivir triphosphate (RTP), on the activity of the replicative mitochondrial DNA polymerase, Pol γ. We found that while RTP is not incorporated by Pol γ into a nascent DNA strand, it remains associated with the enzyme impeding its synthetic activity and stimulating exonucleolysis. In spite of that, we found no evidence for deleterious effects of remdesivir treatment on the integrity of the mitochondrial genome in human cells in culture.

Adenosine Monophosphate/analogs & derivatives , Alanine/analogs & derivatives , COVID-19/drug therapy , DNA Polymerase gamma/metabolism , DNA Replication/drug effects , DNA, Mitochondrial/biosynthesis , Fibroblasts/metabolism , SARS-CoV-2 , Adenosine Monophosphate/pharmacology , Alanine/pharmacology , COVID-19/metabolism , Cells, Cultured , Humans
Immunity ; 54(7): 1463-1477.e11, 2021 07 13.
Article in English | MEDLINE | ID: covidwho-1263294


Acute respiratory distress syndrome (ARDS), an inflammatory condition with high mortality rates, is common in severe COVID-19, whose risk is reduced by metformin rather than other anti-diabetic medications. Detecting of inflammasome assembly in post-mortem COVID-19 lungs, we asked whether and how metformin inhibits inflammasome activation while exerting its anti-inflammatory effect. We show that metformin inhibited NLRP3 inflammasome activation and interleukin (IL)-1ß production in cultured and alveolar macrophages along with inflammasome-independent IL-6 secretion, thus attenuating lipopolysaccharide (LPS)- and SARS-CoV-2-induced ARDS. By targeting electron transport chain complex 1 and independently of AMP-activated protein kinase (AMPK) or NF-κB, metformin blocked LPS-induced and ATP-dependent mitochondrial (mt) DNA synthesis and generation of oxidized mtDNA, an NLRP3 ligand. Myeloid-specific ablation of LPS-induced cytidine monophosphate kinase 2 (CMPK2), which is rate limiting for mtDNA synthesis, reduced ARDS severity without a direct effect on IL-6. Thus, inhibition of ATP and mtDNA synthesis is sufficient for ARDS amelioration.

Adenosine Triphosphate/metabolism , DNA, Mitochondrial/biosynthesis , Inflammasomes/drug effects , Metformin/pharmacology , NLR Family, Pyrin Domain-Containing 3 Protein/metabolism , Pneumonia/prevention & control , Animals , COVID-19/metabolism , COVID-19/prevention & control , Cytokines/genetics , Cytokines/metabolism , DNA, Mitochondrial/metabolism , Humans , Inflammasomes/metabolism , Interleukin-1beta/genetics , Interleukin-1beta/metabolism , Lipopolysaccharides/toxicity , Metformin/therapeutic use , Mice , Nucleoside-Phosphate Kinase/metabolism , Pneumonia/metabolism , Respiratory Distress Syndrome/chemically induced , Respiratory Distress Syndrome/prevention & control , SARS-CoV-2/pathogenicity