Extracellular Vesicles Derived from Hypoxic Human Mesenchymal Stem Cells Attenuate GSK3 beta Expression via miRNA-26a in an Ischemia-Reperfusion Injury Model

Purpose: Bioactive molecules critical to intracellular signaling are contained in extracellular vesides (EVs) and have cardioprotective effects in ischemia/reperfusion (IR) injured hearts. This study investigated the mechanism of the cardioprotective effects of EVs derived from hypoxia-preconditioned human mesenchymal stem cells (MSCs). Materials and Methods: EV solutions (0.4 mu g/mu L) derived from normoxia-preconditioned MSCs (EVNM) and hypoxia-preconditioned MSCs (EVHM) were delivered in a rat IR injury model. Successful EV delivery was confirmed by the detection of PKH26 staining in hearts from EV-treated rats. Results: EVHM significantly reduced infarct size (24 +/- 2% vs. 8 +/- 1%, p<0.001), and diminished arrhythmias by recovering electrical conduction, I-Na current, and Cx43 expression. EVHM also reversed reductions in Wntl and beta-catenin levels and increases in GSK3 beta induced after IR injury. miRNA-26a was significantly increased in EVHM, compared with EVNM, in real-time PCR. Finally, in in vitro experiments, hypoxia-induced increases in GSK3 beta expression were significantly reduced by the overexpression of miRNA-26a. Conclusion: EVHM reduced IR injury by suppressing GSK3 beta expression via miRNA-26a and increased Cx43 expression. These findings suggest that the beneficial effect of EVHM related with Wnt signaling pathway.