Extracellular vesicles Transfer Polarized Mitochondria and Increase Cellular Energetics in Ischemic Endothelial Cells

Extracellular vesicles (EVs) such as exosomes (EXOs) and microvesicles (MVs) are promising carriers for the delivery of biologic drugs such as nucleic acids and proteins. We have demonstrated, for the first time, that EVs derived from hCMEC/D3: a human brain endothelial cell (BEC) line transfer polarized mitochondria to recipient BECs in culture and to neurons in mice acute brain cortical and hippocampal slices. This mitochondrial transfer increased ATP levels by 100 to 200-fold (relative to untreated cells) in the recipient BECs exposed to oxygen-glucose deprivation, an in vitro model of cerebral ischemia. Our previous studies suggested that EXOs, the smaller vesicle subpopulation, derived from a macrophage cell line (RAW264.7) load more exogenous plasmid DNA compared to the larger MVs and the RAW-derived EXOs also demonstrated greater transfection in the recipient BECs compared to EXOs derived from the homotypic hCMEC/D3 BECs. Proteomic analysis of EVs indicated that RAW-EVs are preferentially enriched with proteins that are involved in the trafficking of DNA-containing particles from the cytoplasm towards the nucleus. Intriguingly, although the heterotypic macrophage-derived EVs demonstrated increased transfection in the recipient BECs; the homotypic, BEC-derived EVs demonstrated a greater selectivity to transfer polarized mitochondria and increase endothelial cell survival under ischemic conditions. HighlightsO_LIEVs transfer polarized mitochondria to endothelial cells and acute brain slices C_LIO_LIMitochondrial transfer increased ATP in ischemic brain endothelial cells (BECs) C_LIO_LIBEC-EVs demonstrate greater mitochondrial transfer to recipient BECs C_LIO_LIMacrophage-derived EVs are better DNA transfection agents in recipient BECs C_LIO_LIMacrophage-EVs are enriched in proteins associated with nuclear trafficking of DNA C_LI