UNIVERSITY OF HELSINKI- Mitochondrial Aging Theory questioned: aging is in the nucleus.

ENPNewswire-October 9, 2019--UNIVERSITY OF HELSINKI- Mitochondrial Aging Theory questioned: aging is in the nucleus

(C)2019 ENPublishing - http://www.enpublishing.co.uk

Release date- 08102019 - Disturbances in the function of mitochondrial DNA can accelerate the aging process in ways that are different than previously thought, according to a new Finnish study published in Nature Metabolism.

For almost half a century, mitochondrial DNA (mtDNA) mutations and oxidative stress have been asserted as major contributors to aging, as postulated in the mitochondrial theory of aging by Harman in the 70's. The mtDNA Mutator mice were generated to test this hypothesis by two independent groups (Trifunovic et al. Nature 2004, Kujoth et al. Science 2005).

These mice accumulate mtDNA mutations and present with accelerated aging signs, including grey hair, thin skin, osteoporosis and anemia. Therefore, a conclusion was made that mtDNA mutagenesis drives aging. However, despite rigorous studies by several groups, elevated oxidative stress has not been found in Mutator mouse tissues.

The current study published in Nature Metabolism proposes an alternative explanation for mitochondrial progeria: that mtDNA Mutator mice have compromised nuclear DNA maintenance in their stem cells.

The Mutator mice harbour a defective polymerase-gamma enzyme, and present with pronounced mtDNA mutagenesis. Mutator mouse is the only mitochondrial model which manifests accelerated aging phenotype, despite the existence of other mouse models with equivalent mtDNA mutagenic propensity.

Progeria is not a clinical feature of mitochondrial disease patients either, even in those with high amounts of mtDNA mutations. Rather, the phenotype of the mtDNA Mutator mice is remarkably similar to that of other mouse progeria models and human progeric syndromes with nuclear genome instability, with the most prominent defects in proliferating cells, and especially...

To continue reading

Request your trial

VLEX uses login cookies to provide you with a better browsing experience. If you click on 'Accept' or continue browsing this site we consider that you accept our cookie policy. ACCEPT