血小板活化因子（PAF）调控Hippo/YAP1通路诱导心肌纤维化的分子机制研究

Abnormal regulation of Hippo/YAP1 pathway is involved in the occurrence of cardiovascular diseases, but its regulatory function on myocardial fibrosis is still unclear. We found that YAP1 expression was increased in cardiac fibroblasts of myocardial fibrosis mice. Overexpression of YAP1 promoted collagen synthesis and fibrosis in myocardial fibroblasts. The expression and subcellular localization of YAP1 are regulated by PAF/PAFR.PAF/PAFR promotes fibroblast proliferation and collagen synthesis;YAP1 promotes PAFR expression and predicts transcriptional regulation of PAFR.As a result, we assume that the PAF - PAFR⇌YAP1 / TEAD1 - CTGF pathways regulate myocardial fibrosis. Our project intends to study :(1) the function and mechanism of Hippo/YAP1 pathway in regulating myocardial fibrosis; (2) the role of PAF/PAFR in myocardial fibrosis and its molecular mechanism; (3) PAFR ⇌ YAP1 / TEAD1 feedback loop in the key role in myocardial fibrosis; (4) the therapeutic effect of intervention of PAFR or Hippo/YAP1 pathway on myocardial fibrosis in mice. This project will discuss our understanding of the pathogenesis of myocardial fibrosis and provide important theoretical basis and technical support for the prevention and treatment of myocardial fibrosis.

Hippo/YAP1通路的异常调节参与心血管疾病的发生，但其对心肌纤维化的调控功能尚不明确。我们前期发现：心肌纤维化小鼠心脏成纤维细胞中YAP1表达升高；过表达YAP1促进心肌成纤维细胞胶原合成及细胞纤维性变；YAP1表达及亚细胞定位受PAF/PAFR调控；PAF/PAFR促进成纤维细胞增殖及胶原合成；YAP1促进PAFR表达并预测转录调控PAFR。因此，我们假设PAF→PAFR⇌YAP1/TEAD1→CTGF通路调控心肌纤维化。本项目拟研究：（1）Hippo/YAP1通路调控心肌纤维化的功能及作用机理；（2）PAF/PAFR参与心肌纤维化的作用及分子机制；（3）PAFR⇌YAP1/TEAD1反馈环路在心肌纤维化中的关键作用；（4）干预PAFR或Hippo/YAP1通路对小鼠心肌纤维化的治疗作用。本课题将深化我们对心肌纤维化发病机制的认识，并为心肌纤维化的防治提供重要理论依据和技术支撑。

许多心血管疾病如：高血压、心肌肥厚、心肌梗死等，随着病程的发生发展均会伴有一个共性的病理改变-心肌纤维化，目前仍没有治疗心肌纤维化的理想手段。Hippo/YAP1通路的异常调节参与心血管疾病的发生，但其对心肌纤维化的调控功能尚不明确。血小板活化因子(platelet-activating factor, PAF)是一种重要的细胞因子，其是否参与调控心肌纤维化的发生发展有待深入研究。本课题主要集中于以下研究内容：1.检测PAF及Hippo通路在心肌纤维化中的变化情况；2.阐明Hippo/YAP1通路对心肌纤维化的调控作用；3.明确PAF/PAFR通过 Hippo/YAP1信号通路调控纤维化的作用机制；4.探索PAFR-YAP1/TEAD1环路调控作用机制；5.评价干预PAF/PAFR—Hippo轴对心肌纤维化的治疗作用。. 实验结果发现，PAFR在心肌纤维化时表达升高，PAF表达升高特异性作用于PAFR引起心肌纤维化；心肌梗死动物水平实验发现特异性敲除PARF能后抑制心肌纤维化的发生；过表达YAP1能够激活心肌成纤维细胞向肌成纤维细胞转分化；沉默YAP1能够抑制心肌纤维化；YAP1转录激活PAFR表达；Hippo/YAP1通路参与心肌纤维化的发生，其是PAF/PAFR的下游靶点；PAFR调控YAP1入核与TEAD1结合发挥生物效应，YAP1/TEAD1转录后上调PAFR。. 根据实验结果得出结论：1.血小板活化因子PAF与其特异性受体PAFR对心肌纤维化的调控作用；2.PAF→PAFR⇌YAP1/TEAD1→CTGF调控通路参与心肌纤维化发生发展的调控控过程，在心肌纤维化中的作用机制；3.PAFR与YAP1/TEAD1复合物的正反馈调节机制，进一步佐证PAF/PAFR-Hippo/YAP信号通路在心肌纤维化病程中的重要意义，揭示PAF/PAFR—Hippo/YAP1轴是心肌纤维治疗的潜在靶点。