Extracellular vesicle glycosylation in transport, signaling, and function

Extracellular vesicles (EVs) are thought to be released from virtually all cells from the simplest microorganisms to the most evolutionarily advanced mammals. Only in the past twodecades have these vesicles been recognized to have significant roles in processes such as cell–cell communication, immune activation, immune suppression, disease, and infection. Like the majority of macromolecular structures in mammals, complex carbohydrates are an integral part of human EVs. The carbohydrates of the EV surface and cargo are being widely investigated to understand their functional roles. Due to the biologically limited quantities contained within biofluids and difficulties with purifying and identifying subsets of EVs, much effort has been required to profile and analyze EV glycosylation and to begin to understand how it affects human physiology. In this chapter, a short introduction to the current knowledge of EV glycosylation in terms of functional and clinical significance will be presented. Some examples of recent findings and some of the methodologies used to evaluate EV glycosylation will be discussed.