Only Some Mitochondrial DNA Damage Contributes to Aging

This research might be taken to illustrate the point that only some specific mutations in mitochondrial DNA (mtDNA) contribute to aging - those occurring in one of thirteen specific genes, per the SENS outline. So mice with accelerated mutation rates in all mitochondrial DNA exhibit accelerated aging, while mice with specific mitochondrial mutations that do not include those that contribute to aging do not exhibit accelerated aging. It has been hypothesized that pathogenic mtDNA mutations that induce significant mitochondrial respiration defects cause mitochondrial diseases, and could also be involved in aging and age-associated disorders including tumor development. This hypothesis is partly supported by studies in mtDNA mutator mice: they possess a nuclear-encoded mtDNA polymerase with a defective proofreading function that leads to enhanced accumulation of random mutations in mtDNA with age, and the subsequent phenotypic expression of age-associated respiration defects and premature aging phenotypes, but not tumor development. On the contrary, our previous studies showed that transmitochondrial mito-miceΔ carrying mtDNA with a large-scale deletion mutation (ΔmtDNA) expressed age-associated respiration defects, but not express the premature aging phenotypes. Similar results were obtained in other transmitochondrial mito-miceCOIM, which have an mtDNA point mutation in the COI gene. Recently, we generated new transmitochondrial mito-miceND6M, which have an mtDNA point mut...
Source: Fight Aging! - Category: Health Medicine and Bioethics Commentators Authors: Tags: Daily News Source Type: blogs