Composition of cardiac-derived extracellular vesicles changes with vesicle origin and determines uptake.

Introduction: Cardiovascular disease (CVD) is a leading cause of mortality worldwide. The potency of cell-based therapies for CVD is increasingly attributed to the release of small extracellular vesicles (sEVs) which consist of a lipid/protein membrane and encapsulate nucleic cargo. Specifically, sEVs from ckit + progenitor cells (CPCs) and mesenchymal stromal cells (MSCs) are shown to be pro-reparative, with clinical trials conducted. Despite copious research into sEV cargo, the role of parent cell type on sEV membrane composition and its effects on sEV uptake mechanism by recipient cells remain unclear. This is crucial for designing sEV-based therapeutics as uptake mechanism dictates the functionality of the cargo. Methods: In this study we investigate the role of sEV parent cell and membrane composition on the mechanism of EV uptake by recipient cells. Results: We find that sEV membrane lipid and protein composition varies by parent cell type. Further, vesicle uptake mechanism varies by both sEV parent cell type and recipient cell type, with clathrin-mediated uptake being the most variable across parent cell conditions. Using a partial least squares regression model, we observe that proteins important in clathrin-mediated uptake (e.g., TPM1, MRC2, FSTL1, LTBP1) are dissimilar to other vesicle uptake mechanisms. Discussion: This work underscores the importance of the sEV source and membrane composition on uptake, and in turn the importance of selecting specific sEVs based on the target recipient cells for CVD therapies.