Extracellular microvesicles (MVs) and exosomes (EXs) can mark the changes of their origin cells. They can transfer their carried messages (proteins, mRNAs, and microRNAs) to target cells to modulate the functions of the recipient cells. Therefore, MVs and EXs are recognized as potential biomarkers and important therapeutic targets or tools for a wide spectrum of diseases including vascular and neurological diseases and cancers. While research in stem cells has achieved significant advances during the past decades, there is less information regarding the roles of MVs and EXs released from stem cells.
(A) Timeline (1956–2014) of the publications referring to extracellular vesicles (black line), microvesicles (blue line), and exosomes (red line). (B) Schematic representation of the mechanisms of formation of microvesicles, exosomes, and apoptotic bodies. Microvesicles (0.2–2.0 μm) originate via budding and shedding from the plasma membrane of cells and therefore may contain specific surface markers from the cell of origin. Exosomes (50–100 nm) on the other hand originate intracellularly through a sorting pathway involving intermediate organelles such as the early endosome and a late multivesicular body, which fuses with the plasma membrane to release exosomes via exocytosis. Apoptotic bodies (1–2 μm) originate via blebbing of the plasma membrane.
There is an urgent need to identify sensitive and specific methods for the isolation and identification of MVs and EXs, which is very important and challenging. (read more…)