Analysis of Extracellular Vesicle-Associated Proteoglycans.

Extracellular vesicles (EVs) have emerged as a central mechanism of intercellular communication in physiology and disease. EVs participate in paracrine exchange of nucleic acids as well as lipids, proteins, and glycans to elicit a complex biological response in target cells. Proteoglycans (PGs) are widely expressed in EV-producing cells and are sorted to the membrane of secreted EVs to participate in some of the key processes in EV-mediated signaling. Most notably, PGs mainly of the heparan sulfate (HS) type are involved in EV biogenesis and cellular uptake of EVs through endocytic processes. EV-associated PGs may serve as short- and long-range chaperones of signaling molecules with potential implications for intercellular information exchange, most importantly in cancer development. This motivates the development of approaches targeting EV-HSPG interactions as a strategy in cancer treatment. Moreover, the importance of PG remodeling and alterations in their expression in cancer, together with the fact that EVs mimic their cell or tissue of origin, point at an important role of EV-associated PGs as disease biomarkers. Here, we provide methodological insights into the analysis of EV-PGs isolated from cell cultures as well as patient plasma liquid biopsy.