Induced pluripotent stem cell-derived extracellular vesicles enriched with miR-126 induce proangiogenic properties and promote repair of ischemic tissue

Emerging evidence suggests that stem cell-derived extracellular vesicles (EVs) may induce pro-regenerative effects in ischemic tissues by delivering bioactive molecules, including microRNAs. Recent studies have also shown pro-regenerative benefits of EVs derived from induced pluripotent stem (iPS) cells. However, the underlying mechanisms of EV benefits and the role of their transferred regulatory molecules remain incompletely understood. Accordingly, we investigated the effects of human iPS-derived EVs (iPS-EVs) enriched in proangiogenic miR-126 (iPS-miR-126-EVs) on functional properties of human endothelial cells (ECs) in vitro. We also examined the outcomes following EV injection in a murine model of limb ischemia in vivo. EVs were isolated from conditioned media from cultures of unmodified and genetically modified human iPS cells overexpressing miR-126. The iPS-miR-126-EVs were enriched in miR-126 when compared with control iPS-EVs and effectively transferred miR-126 along with other miRNAs to recipient ECs improving their functional properties essential for ischemic tissue repair, including proliferation, metabolic activity, cell survival, migration, and angiogenic potential. Injection of iPS-miR-126-EVs in vivo in a murine model of acute limb ischemia promoted angiogenesis, increased perfusion, and enhanced functional recovery. These observations corresponded with elevated expression of genes for several proangiogenic factors in ischemic tissues following iPS-miR-126-EV transplantation. These results indicate that innate pro-regenerative properties of iPS-EVs may be further enhanced by altering their molecular composition via controlled genetic modifications. Such iPS-EVs overexpressing selected microRNAs, including miR-126, may represent a novel acellular tool for therapy of ischemic tissues in vivo.