Enrichment of miR-126 Boosts the Therapeutic Effects of Endothelial Progenitor Cells Derived Exosomes on Ischemic Stroke in Diabetic Mice

<p> <p id="x-x-x-p-2"> We have demonstrated that endothelial progenitor cell (EPCs) have therapeutic effects on ischemic stroke in diabetic mice and that microRNA (miR)-126 modulates the function of EPC through vascular endothelial growth factor receptor 2 (VEGFR2) pathway in cell culture studies. Here, we determined the effects of EPC-released exosomes (EPC-EXs) on ischemic stroke in diabetic mice and tested whether miR-126 enriched EPC-EXs (EPC-EXsmiR126) could have enhanced efficacy. Type 2 diabetic mice subjected to filament-induced focal ischemic stroke were intravenously administrated with vehicle, or PKH26 labelled EPC-EXs or EPC-EXsmiR-126. The neurological deficit score (NDS), cerebral blood flow (CBF), infarct volume, cerebral microvascular density (MVD), cell death, angiogenesis and neurogenesis, and levels of miR-126, VEGFR2 and cleaved caspase-3 were measured. We found: 1) Injected EPC-EXs merged with brain endothelial cells, neurons and astrocytes dominantly in the peri-infarct area; 2) EPC-EXsmiR126 were more effective than EPC-EXs in decreasing NDS, ischemic damage and cell death, and increasing CBF and MVD on both day 2 and 14, and in promoting angiogenesis and neurogenesis on day 14; 3) These effects were accompanied with down-regulated cleaved caspase-3 on day 2 and prolonged VEGFR2 up-regulation till day 14. The data suggest that transfusion of EPC-EXsmiR126 has enhanced therapeutic efficacy on ischemic stroke in diabetic mice by attenuating acute injury and promoting neurological function recovery. </p></p>