Every cell in the body can release several types of extracellular vesicles (EVs), often called ”exosomes” or ”microvesicles”. These vesicles carry a wide array of molecules, including functional proteins and enzymes, as well as different RNA species (mRNA, microRNA and other species), all protected by a membrane lipid bilayer. EVs have the capacity to deliver molecular cargo to recipient cells by multiple pathways, including fusion at the level of the cell membrane, or by being internalized by cells. Current research is suggesting a wide diversity of extracellular vesicles , with diverse morphology according to electron microscopy studies, and difference in RNA and protein cargo according to bioinformatics analyses.
EVs have been implicated in several ways in disease. For example, in cancer, it has been shown that the number of EVs increase in the circulation. EVs can propagate disease in several ways, for example in cancer by enhancing angiogenesis and propagating metastasis, as well inducing immune tolerance. Furthermore, several studies today have suggested that the cargo of EVs released in disease states such as cancer, including proteins and RNA, will fundamentally change, which can explain changes in function.
This lecture will lay the background to EVs and will discuss extensively the diversity of EVs released by single cell types in culture, and diversity of EVs in body fluids, discussing their relevance for cell-to-cell communication.