Healthy Aging More Doubtful if Nuclear and Mitochondrial Genomes Clash

What is Mitochondrial DNA(mtDNA)?

Mitochondrial DNA is the genetic material in the mitochondria, which produces energy for cells (ATP), a form of deoxyribonucleic acid found inside the mitochondria of cells. Mitochondria are organelles that provide power (ATP) to cells. There are generally multiple DNA molecules in mitochondria.

They carry their DNA, mtDNA, and mutations in these genes can cause mitochondrial diseases. While disease symptoms are variable, energy-intensive organs such as the brain, muscles, and heart are often affected. Since mitochondria are mainly transmitted through egg cells, related diseases are mostly inherited from the mother.

Mitochondrial DNA (mtDNA) doesn’t have to be pathogenic or intrinsically flawed to impair health. It just has to be a poor match with nuclear DNA. Scientists at the Centro Nacional de Investigaciones Cardiovasculares (CNIC) have uncovered how the combination and interaction between our two genomes, the nuclear and the mitochondrial, triggers a cellular adaptation that has repercussions throughout our lives and determines how we age.

Mitochondrial DNA (mtDNA) doesn’t have to be pathogenic or intrinsically flawed to impair health. It just has to be a poor match with nuclear DNA. Scientists at the Centro Nacional de Investigaciones Cardiovasculares (CNIC) have uncovered how the combination and interaction between our two genomes, the nuclear and the mitochondrial, triggers a cellular adaptation that has repercussions throughout our lives and determines how we age.

Mitochondrial fitness has been under heightened scrutiny of late, given the rise of mitochondrial donation technology and the production of “three-parent” babies. Mitochondrial donation procedures are designed to prevent the transmission of disease-causing mtDNA. Such processes might also account for the health impacts of nonpathogenic mtDNA variants.

Studies of nonpathogenic mtDNA variants have been conducted in “plastic” animals, that is, strains in which the nuclear genome from one theme has been crossed onto another cytoplasm. These studies have given equivocal results, partly because they have tended to focus on younger animals. Also, they have not investigated the full scope of physiological and phenotypic variability likely to be influenced by mitochondria.

To improve on these studies, the CNIC scientists systematically characterized con plastic mice throughout their lifespans using transcriptomic, proteomic, metabolomic, biochemical, physiological, and phenotyping studies. The results of this work were presented on July 6 in the journal Nature in an article entitled “Mitochondrial and Nuclear DNA Matching Shapes Metabolism and Healthy Ageing.”

The article shows that nonpathogenic mtDNA variants impact organismal metabolism and aging differently. According to the article’s senior author, the CNIC’s José Antonio Enríquez, Ph.D., nonpathogenic differences in mitochondrial function have direct repercussions on the pace of aging. “Variation in just a few genes,” he asserted, “can determine whether we experience healthy aging.”

“We show,” wrote the authors of the Nature article, “that mtDNA haplotype profoundly influences mitochondrial proteostasis and reactive oxygen species generation, insulin signaling, obesity, and aging parameters including telomere shortening and mitochondrial dysfunction, resulting in profound differences in health longevity between plastic strains.”

“The key to this study was understanding how the combination and interaction of our two genomes, the nuclear and the mitochondrial, triggers a cellular adaptation with repercussions throughout our lives,” explained the study’s first author, the CNIC’s Ana Latorre-Pellicer, Ph.D.

The CNIC team obtained robust evidence that the simple measure of changing an animal’s mtDNA triggers a series of adaptive cellular mechanisms in young animals that ensure a more healthy aging process. “If we can understand the biology underlying healthy aging that is free of age-associated diseases, we will be in a position to maintain long-lasting health during the aging process,” affirmed Dr. Latorre-Pellicer.