Mitochondrial DNA in Extracellular Vesicles Declines with Age

A sizable fraction of cell signaling is conveyed via extracellular vesicles, tiny membrane-wrapped packages of molecules. Here researchers note that mitochondrial DNA is found inside extracellular vesicles, and that the amount declines with age. Other researchers have determined that entire mitochondria are exported and taken up by cells, so one has to carefully read the methods used in papers like this to ensure that researchers are in fact looking at the smaller extracellular vesicles only. These vesicles are sorted into category by size, and selecting by size is an established capability. It is speculated that transfer of mitochondrial DNA via extracellular vesicle serves useful purposes, and observed in cell cultures that it can alter mitochondrial function in recipient cells. Additionally it can serve as a signal of damage generated by stressed and dying cells, activating the immune system to be more vigilant. Alternatively, it may be a garbage disposal mechanism to get rid of unwanted molecules, and uptake of these vesicles is a form of unwanted side-effect. A declining presence of mitochondrial DNA in extracellular vesicles with age might be a simple reflection of a lesser number of mitochondria in cells, a part of the general faltering of mitochondrial function in old tissues, or it may be the consequence of a much more complex set of processes. The evidence to date leans in the latter direction, as is usually the case in biological systems. Mitoc...
Source: Fight Aging! - Category: Research Authors: Tags: Medicine, Biotech, Research Source Type: blogs