HucMSC-exosomes促进AMI炎症期成纤维细胞表型转化保护心肌损伤机制研究

Recently, the repair role of exosomes in myocardial injury attracted a wide spread attention, but the mechanism has not been fully elucidated. Our preliminary experiments have confirmed the cardiac function improved effect of exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-exosomes) in AMI rats, and hucMSC-exosomes can prompt the transformation of cardiac fibroblasts into myofibroblasts during the inflammatory period. So we hypothesize that hucMSC-exosomes carrying key protein may help to increase myofibroblasts, inhibit inflammation progress, protect myocardium. We will study the mechanism of fibroblasts phenotype transformation prompted by hucMSC-exosomes to protect myocardium using experiments in vitro and in vivo. In addition, we will looking for the key protein and mechanism of hucMSC-exosomes according to the preliminary results of proteomics, which may provide a new mechanism for exosomes based repair for AMI, and also provide experimental basis for exploring higher efficacy exosomes, show a great significance and potential clinical application value.

近年来细胞外泌体在心肌损伤修复中的作用倍受关注，但其作用机制还未完全阐明。我们也证实人脐带间质干细胞来源exosomes（hucMSC-exosomes）可改善AMI大鼠心功能，促进炎症期心脏成纤维细胞转化为肌成纤维细胞，因此我们假说在AMI修复早期（炎症期），hucMSC-exosomes运载关键蛋白促进肌成纤维细胞增加，从而抑制炎症进展保护心肌促进修复。本课题将采用体内外实验研究hucMSC-exosomes促进修复早期心脏成纤维细胞表型转化保护心肌损伤作用，根据前期蛋白质组学分析结果，筛选hucMSC-exosomes中关键蛋白及作用机制，为exosomes修复AMI提供新的机制，也为探寻更高疗效的exosomes提供实验基础，具有重要意义和潜在临床应用价值。

细胞外泌体在心肌损伤修复中的作用倍受关注，但其作用机制还未完全阐明。可能涉及炎症抑制、抗凋亡、促进血管形成等。前期研究已证明人脐带间质干细胞来源exosomes（hucMSC-ex）可改善心肌梗死（MI）大鼠心功能。另有研究报道MI后，成纤维细胞被激活，继而转化为肌成纤维细胞，后者是参与MI损伤修复过程的主要细胞。本研究旨在探究hucMSC-ex是否在MI炎症期促进心脏成纤维细胞转化为肌成纤维细胞，发挥抗炎抗凋亡及促进血管形成作用，并寻找hucMSC-ex中关键蛋白及作用机制。体内实验发现在MI炎症期hucMSC-ex注射组梗死区肌成纤维细胞数量较PBS注射组增多，体外试验也表明，hucMSC-ex促进炎症条件下心脏成纤维细胞向肌成纤维细胞转化。转化后肌成纤维细胞收缩能力增加，细胞迁移能力降低，炎症因子表达降低，而炎症抑制因子表达增加。心肌细胞缺氧诱导实验发现转化后的肌成纤维细胞可抑制缺氧诱导的心肌细胞凋亡。Galectin-3在心肌成纤维细胞表型转化中发挥重要作用，hucMSC-ex中可检测到Galectin-3蛋白，在炎症环境下，hucMSC-ex来源Galectin-3在促进心肌成纤维细胞向肌成纤维细胞转化，抗炎抗凋亡中起重要作用。此外hucMSC-ex增强了肌成纤维细胞及炎症条件下成纤维细胞促血管生成作用，进一步RNA测序及功能学验证在炎症环境中，hucMSC-ex通过Angptl4调节心脏成纤维细胞促进血管生成。这些研究为间质干细胞来源exosomes与心肌损伤修复相关研究提供了新的机制，有望为将来exosomes用于损伤修复相关治疗提供实验依据。