Endonuclease G promotes hepatic mitochondrial respiration by selectively increasing mitochondrial tRNAThr production
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ABSTRACT: Mitochondrial endonuclease G (EndoG) contributes to chromosomal degradation when it is released from mitochondria during apoptosis. It is presumed to also have a mitochondrial function because EndoG-deficiency causes mitochondrial dysfunction. However, the mechanism by which EndoG regulates mitochondrial function is not known. Fat accumulation in metabolic dysfunction-associated steatotic liver disease (MASLD), which is more common in men, is caused in part by mitochondrial dysfunction. EndoG expression is reduced in MASLD liver and EndoG-deficiency causes MASLD in an obesity-independent manner but only in males. EndoG promotes mitochondrial respiration by resolving mitochondrial tRNA/DNA hybrids formed during mtDNA transcription by recruiting RNA helicase DHX30 to unwind them. EndoG also cleaves off the 3’-end of the H-strand transcript that can prevent mt-tRNAThr precursor cloverleaf-folding, and processing, which increases mt-tRNAThr production and mitochondrial translation. Using fluorescent lifetime imaging microscopy (FLIM) technology to visualize oxygen consumption at the individual mitochondrion level, we found that EndoG-deficiency leads to the selective loss of a mitochondrial subpopulation with high-oxygen consumption. This defect was reversed with mt-tRNAThr supplementation. Thus, EndoG promotes mitochondrial respiration by selectively regulating the production of mt-tRNAThr in males.
ORGANISM(S): Mus musculus
PROVIDER: GSE285206 | GEO | 2024/12/27
REPOSITORIES: GEO
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