Cardiac progenitor cell-derived extracellular vesicles promote angiogenesis through both associated- and co-isolated proteins

Extracellular vesicles (EVs) are cell-derived lipid bilayer-enclosed particles that play a role in intercellular communication. Cardiac progenitor cell (CPC)-derived EVs have been shown to protect the myocardium against ischemia-reperfusion injury via pro-angiogenic effects. However, the mechanisms underlying CPC-EV-induced angiogenesis remain elusive. Here, we discovered that the ability of CPC-EVs to induce in vitro angiogenesis and to stimulate pro-survival pathways was lost upon EV donor cell exposure to calcium ionophore. Proteomic comparison of active and non-active EV preparations together with phosphoproteomic analysis of activated endothelial cells identified the contribution of candidate protein PAPP-A and the IGF-R signaling pathway in EV-mediated cell activation, which was further validated using in vitro angiogenesis assays. Upon further purification using iodixanol gradient ultracentrifugation, EVs partly lost their activity, suggesting a co-stimulatory role of co-isolated proteins in recipient cell activation. Our increased understanding of the mechanisms of CPC-EV-mediated cell activation will pave the way to more efficient EV-based therapeutics.

The functional role of surface molecules on extracellular vesicles in cancer, autoimmune diseases, and coagulopathy

Extracellular vesicles (EVs) are nanosized particles that have emerged as mediators for intercellular communication in physiologic and pathologic conditions. EVs carry signaling information on their bilipid membrane as well as cargo within, allowing them to perform a wide range of biologic processes and contribute to pathophysiologic roles in a wide range of diseases, including cancer, autoimmune diseases and coagulopathy. This review will specifically address the function of surface molecules on EVs under normal and diseased conditions, as well as their potential to emerge as therapeutic targets in clinical settings, and the importance of further research on the surface topography of EVs.