Mitochondrial movement between mammalian cells: an emerging physiological phenomenon

The mammalian mitochondrial genome has evolved into an essential circular mini-chromosome present in multiple copies inside mitochondria of all nucleated cells in the body. Consistent with their microbial origin, mitochondria can no longer be considered to be cell-constrained as a growing body of evidence shows that they not only can, but do move between cells demonstrating that horizontal transfer of mitochondrial genes is a normal (patho)physiological process in animal models of disease and in humans. While the molecular mechanisms driving intercellular mitochondrial transfer remain uncertain, functional consequences include respiration recovery and bioenergetic remodeling. Mitochondrial uptake by damaged cells has been demonstrated in vivo, and therapeutic applications of mitochondrial therapy following cardiac damage, brain ischemia-reperfusion injury, and lung inflammation have been described supporting the concept of physiologically important mitochondrial trafficking between cells.