Abstract
Mitochondrial transfer is highly significant under physiological as well as pathological states given the emerging recognition of mitochondria as cellular "processors" akin to microchip processors that control the operation of a mobile device. Mitochondria play indispensable roles in healthy functioning of the brain, the organ with the highest energy demand in the human body and therefore, loss of mitochondrial function plays a causal role in multiple brain diseases. In this review, we will discuss various aspects of extracellular vesicle (EV)-mediated mitochondrial transfer and their effects in increasing recipient cell/tissue bioenergetics with a focus on these processes in brain cells. A subset of EVs with particle diameters >200 nm, referred to as medium-to-large EVs (m/lEVs), are known to entrap mitochondria during EV biogenesis. The entrapped mitochondria are likely a combination of either polarized, depolarized mitochondria or a mixture of both. We will also discuss engineering approaches to control the quality and quantity of mitochondria entrapped in the m/lEVs. Controlling mitochondrial quality can allow for optimizing/maximizing the therapeutic potential of m/lEV mitochondria-a novel drug with immense potential to treat a wide range of disorders associated with mitochondrial dysfunction.