基于OPN/AP-1/miRNA-21信号通路探讨放射性心肌纤维化的发生机制及当归红芪超滤物的干预效应

Radiation-induced myocardial fibrosis is the main pathological change of the delayed cardiac injury induced by the radiation therapy for thoracic tumor. Myocardial fibroblasts proliferation and collagen deposition induced by OPN / AP-1 / miRNA-21 signaling pathway plays a key role for the occurrence of myocardial fibrosis. According to the “QI-Xue” theory of traditional Chinese medicine and basing on the results obtained in our recent experiments, we here hypothesis that molecular biological mechanism of protecting from radiation-induced myocardial fibrosis treated by the ultra-filtration extracted of Angelica Sinensis and Hedysarum Polybotrys with “Yi qi-Huo xue” function is the inhibition of myocardial fibroblasts proliferation and collagen deposition by inhibiting the OPN / AP-1 / miRN-A21 signaling pathway. This research intends to investigate the relationship between OPN / AP-1 / miRNA-21 signaling pathway and myocardial fibroblasts proliferation and collagen deposition, hunt for miRNA-21 target gene and downstream signaling pathway in the process of myocardial fibroblasts proliferation and collagen deposition, and illustrate action mechanism of ultra-filtration extracted of Angelica Sinensis and Hedysarum Polybotrys protecting from radiation-induced myocardial fibrosis by some techniques such as gene silencing, gene transfer, biochip detective. The research will be great significance of guidance to prevent and treat of radiation-induced myocardial fibrosis as well as improve the effect of radiation therapy.

放射性心肌纤维化是胸部肿瘤放射治疗引起心脏迟发性损伤的主要病理变化，OPN / AP-1 / miRNA-21信号通路介导心肌成纤维细胞增殖和胶原沉积对心肌纤维化的发生起到关键作用。本项目以中医“气血”理论为指导，基于前期研究结果提出具有“益气活血”功效的当归红芪超滤物治疗放射性心肌纤维化的分子生物学内涵是“通过抑制OPN / AP-1 / miRNA-21信号通路来抑制心肌成纤维细胞增殖和胶原沉积，以保护放射性心肌纤维化”的假说。本项目拟采用基因沉默、转染、芯片检测等技术研究OPN / AP-1 / miRNA-21信号通路与心肌成纤维细胞增殖和胶原沉积之间的关系，寻找心肌成纤维细胞增殖和胶原沉积过程中miRNA-21的下游靶基因及信号通路，阐明当归红芪超滤物保护放射性心肌纤维化的作用机制。本项目将对防治放射性心肌纤维化及提高肿瘤治疗疗效具有重要意义。

本项目采用基因沉默、转染、芯片检测等技术研究OPN/AP-1/miRNA-21信号通路与心肌成纤维细胞增殖和胶原沉积之间的关系，寻找心肌成纤维细胞增殖和胶原沉积过程中miRNA-21的下游靶基因及信号通路。我们的工作证实，放射治疗后新生大鼠心肌成纤维细胞以及辐射损伤大鼠模型心肌成纤维细胞中TGF-β1、OPN、AP-1、miR-21-5p表达增高，抑制TGF-β1可以分别抑制其下游基因OPN、AP-1，Col-1蛋白以及miR-21-5p的表达。同时，研究发现X射线通过miR-21-5p促进活性氧ROS的产生、降低心肌成纤维细胞TNF-α和Caspase-3的表达。另外，研究发现当归红芪超滤物通过降低大鼠心肌组织TGF-β1与Col1α的表达和大鼠血清TnT的水平有效的保护放射性心肌纤维化的发生，其机制为当归红芪超滤物通过调节TGF-β1/OPN/AP-1/miRNA-21通路保护了放射性心肌纤维化的发生。本项目阐明当归红芪超滤物保护放射性心肌纤维化的作用机制，对防治放射性心肌纤维化及提高肿瘤治疗疗效具有重要意义。