Tanshinone ⅡA Enhances the Therapeutic Efficacy of Mesenchymal Stem Cells Derived Exosomes in Myocardial Ischemia/reperfusion Injury via Up-regulating miR-223-5p

Abstract Background: Myocardial ischemia-reperfusion (I/R) injury is a serious obstacle for patients with coronary heart disease to benefit from post-ischemic reflow. After myocardial I/R injury, CCR2+-resident macrophages are rapidly activated and participate in the subsequent inflammatory response, whereas CCR2--resident macrophages play a major role in attenuating cardiac inflammation and promoting tissue repair. Mesenchymal stem cells (MSCs) have gradually become attractive candidates that aid in understanding the pathogenesis and progression of cardiovascular diseases. The low immunogenicity and low carcinogenicity of stem cell-derived exosomes offer advantage in treating myocardial injuries. In this study, we investigated whether MSC-derived exosomes pretreated with tanshinone IIA (TSA) could exhibit stronger cardioprotective function in an I/R rat model and explored its underlying mechanism. Methods: We investigated the effect of TSA-MSCexo on myocardial I/R injury in vivo. The overexpression of CCR2 in the rat heart was used to determine the regulatory role of CCR2 in I/R injury. High-throughput sequencing of MSCexo and TSA-MSCexo to screen differential genes to explore the mechanism of TSA-MSCexo's cardioprotective effect. Results: Compared with MSCexo, an intramyocardial injection of TSA-MSCexo was found to be more effective in rats in improving cardiac function, limiting the infarct size, inhibiting CCR2 activation, reducing monocyte infiltration and promoting angiogenesis in the heart after myocardial I/R. Moreover, CCR2 had a regulatory effect on monocyte infiltration and angiogenesis after I/R. Bioinformatics analysis and miRNA sequencing of MSCexo and TSA-MSCexo revealed miR-223-5p an effective candidate mediator for TSA-MSCexo to exert its cardioprotective function and CCR2 as the downstream target. Conclusion: In summary, our findings indicated that miR-223-5p packaged in TSA-MSCexo inhibited CCR2 activation to reduce monocyte infiltration and enhanced angiogenesis to alleviate myocardial I/R injury in rats. Thus, the development of an alternative therapy of TSA combined with stem cell-derived exosomes provides an effective strategy for the clinical therapies of ischemic cardiomyopathy.