Extracellular vesicles in motion

Abstract

By secreting extracellular vesicles (EVs), including exosomes and microvesicles, into the extracellular milieu, cells can convey complex biological messages between each other. These vesicles are generally thought to be static packages lacking the flexibil-ity of their parental cells in terms of motility and the ability to change shape. However, cryo-electron micrographs reveal the presence of actin-like filaments in a subpopulation of EVs, raising the question if these vesicles could possess motile capabilities similar to that produced by actin in cells. We here show that fluorescently labeled EVs change their shape in a matter of minutes, regardless of whether they are isolated from human body fluids, mouse tissue or cell culture of human cells or yeast. Our findings therefore cast doubt on movement being confined to cells, suggesting that some EVs indeed have an intrinsic capacity to move. This novel observation showing morphological plastic-ity among EVs adds another level of complexity to the already multifaceted vesicular secretome, and may lead to new ways in which we perceive these nano-carriers of in-tercellular signals. Objective Our objective was to evaluate if EV have the ability to change shape and/or move.