Dataset Information
Mitochondrial DNA deletion mutations increase exponentially with age in human skeletal muscle.
Ontology highlight
ABSTRACT: Background
Mitochondrial DNA (mtDNA) deletion mutations lead to electron transport chain-deficient cells and age-induced cell loss in multiple tissues and mammalian species. Accurate quantitation of somatic mtDNA deletion mutations could serve as an index of age-induced cell loss. Quantitation of mtDNA deletion molecules is confounded by their low abundance in tissue homogenates, the diversity of deletion breakpoints, stochastic accumulation in single cells, and mosaic distribution between cells.Aims
Translate a pre-clinical assay to quantitate mtDNA deletions for use in human DNA samples, with technical and biological validation, and test this assay on human subjects of different ages.Methods
We developed and validated a high-throughput droplet digital PCR assay that quantitates human mtDNA deletion frequency.Results
Analysis of human quadriceps muscle samples from 14 male subjects demonstrated that mtDNA deletion frequency increases exponentially with age-on average, a 98-fold increase from age 20-80. Sequence analysis of amplification products confirmed the specificity of the assay for human mtDNA deletion breakpoints. Titration of synthetic mutation mixtures found a lower limit of detection of at least 0.6 parts per million. Using muscle DNA from 6-month-old mtDNA mutator mice, we measured a 6.4-fold increase in mtDNA deletion frequency (i.e., compared to wild-type mice), biologically validating the approach.Discussion/conclusions
The exponential increase in mtDNA deletion frequency is concomitant with the known muscle fiber loss and accelerating mortality that occurs with age. The improved assay permits the accurate and sensitive quantification of deletion mutations from DNA samples and is sufficient to measure changes in mtDNA deletion mutation frequency in healthy individuals across the lifespan and, therefore, patients with suspected mitochondrial diseases.
SUBMITTER: Herbst A
PROVIDER: S-EPMC7985047 | biostudies-literature | 2021 Jul
REPOSITORIES: biostudies-literature
Publications
Mitochondrial DNA deletion mutations increase exponentially with age in human skeletal muscle.
Aging clinical and experimental research 20200923 7
<h4>Background</h4>Mitochondrial DNA (mtDNA) deletion mutations lead to electron transport chain-deficient cells and age-induced cell loss in multiple tissues and mammalian species. Accurate quantitation of somatic mtDNA deletion mutations could serve as an index of age-induced cell loss. Quantitation of mtDNA deletion molecules is confounded by their low abundance in tissue homogenates, the diversity of deletion breakpoints, stochastic accumulation in single cells, and mosaic distribution betwe ...[more]
