Mitochondrial DNA-deletion Mutations Accumulate Intracellularly to Detrimental Levels in Aged Human Skeletal Muscle Fibers
Overview
Authors
Affiliations
Skeletal muscle-mass loss with age has severe health consequences, yet the molecular basis of the loss remains obscure. Although mitochondrial DNA (mtDNA)-deletion mutations have been shown to accumulate with age, for these aberrant genomes to be physiologically relevant, they must accumulate to high levels intracellularly and be present in a significant number of cells. We examined mtDNA-deletion mutations in vastus lateralis (VL) muscle of human subjects aged 49-93 years, using both histologic and polymerase-chain-reaction (PCR) analyses, to determine the physiological and genomic integrity of mitochondria in aging human muscle. The number of VL muscle fibers exhibiting mitochondrial electron-transport-system (ETS) abnormalities increased from an estimated 6% at age 49 years to 31% at age 92 years. We analyzed the mitochondrial genotype of 48 single ETS-abnormal, cytochrome c oxidase-negative/succinate dehydrogenase-hyperreactive (COX-/SDH++) fibers from normal aging human subjects and identified mtDNA-deletion mutations in all abnormal fibers. Deletion mutations were clonal within a fiber and concomitant to the COX-/SDH++ region. Quantitative PCR analysis of wild-type and deletion-containing mtDNA genomes within ETS-abnormal regions of single fibers demonstrated that these deletion mutations accumulate to detrimental levels (>90% of the total mtDNA).
Zhou Q, Zhou S, Chen Z, Zhou W, Su J, Wang Y Nutr Metab (Lond). 2025; 22(1):6.
PMID: 39844270 PMC: 11752774. DOI: 10.1186/s12986-025-00894-4.
Mapping mitochondrial morphology and function: COX-SBFSEM reveals patterns in mitochondrial disease.
Faitg J, Davey T, Laws R, Lawless C, Tuppen H, Fitton E Commun Biol. 2025; 8(1):24.
PMID: 39789156 PMC: 11718190. DOI: 10.1038/s42003-024-07389-7.
El Fissi N, Rosenberger F, Chang K, Wilhalm A, Barton-Owen T, Hansen F Nat Commun. 2024; 15(1):10719.
PMID: 39715749 PMC: 11666730. DOI: 10.1038/s41467-024-55559-2.
Vandiver A, Torres Jr A, Sanden A, Nguyen T, Gasilla J, Doan M Aging Cell. 2024; 24(3):e14402.
PMID: 39680477 PMC: 11896400. DOI: 10.1111/acel.14402.
Vandiver A, Herbst A, Stothard P, Wanagat J Genome Res. 2024; 35(1):55-65.
PMID: 39603705 PMC: 11789635. DOI: 10.1101/gr.279072.124.