IFN-γ Enhances the Efficacy of Exosomes Derived from Mesenchymal Stem Cells in Myocardial Infarction Rats via miR-21 Stimulated by STAT1
Abstract Background: Mesenchymal stem cells (MSCs) activated with IFN-γ elicit more powerful physical effects. Exosomes (Exos) secreted from MSCs have protective against myocardial injury. The aim of this study was to investigate whether Exsos derived from IFN-γ-pretreated MSCs exhibit more potent cardioprotective function and the underlying mechanisms. Methods: Exos were isolated from MSCs (Ctrl-Exo) and IFN-γ-primed MSCs (IFN-γ-Exo) and were then delivered to H9c2 cells or human umbilical vein endothelial cells (HUVECs) in vitro under oxygen and glucose deprivation (OGD) condition or in vivo in an infarcted rat heart. RNA sequencing was to identify the different expressed functional transcription factor (TF). Quantitative reverse transcription-PCR (qPCR) was to confirm the upregulated TF and miRNA in IFN-γ-primed MSCs. Dual-luciferase reporter gene assay were to analyze the transcriptional regulation of miRNAs by STAT1. The target of miR-21-5p (miR-21) was disclosed by luciferase reporter assays and qPCR. The function of BTG2 was verified in vitro under OGD condition.Result: IFN-γ-Exo accelerated migration, tube-like structure formation, and prevented H9c2 from OGD-induced apoptosis. Similarly, IFN-γ-Exo leaded to further reduction in fibrosis size, reduced cardiomyocyte apoptosis and improved cardiac function compared to Ctrl-Exo. miR-21 was significantly upregulated in both IFN-γ-primed MSCs and IFN-γ-Exo. STAT1 transcriptionally induced miR-21 expression. Up-regulated miR-21 can inhibit the expression of BTG2. BTG2 promoted H9c2 cells apoptosis and reversed the protective effect of miR-21 under OGD environment.Conclusion: IFN-γ-Exo have enhanced therapeutic efficacy against acute MI possibly through promoting angiogenesis and anti-apoptotic effect through increasing the level of miR-21, which directly targeted on BTG2.