前肾素受体通过Hippo-YAP通路对高血压合并糖尿病心肌损伤的影响及意义

Recent study showed that hypertension with diabetes may induce more serious and earlier myocardial injury than single disease. The (pro)renin receptor (PRR) is considered as a novel bioactive molecule of the renin-angiotensin system (RAS) ,and it plays an important role in hypertension, diabetes and their complications. Previous study showed that high glucose up-regulated PRR protein expression, and our study found that PRR overexpression activated Hippo-YAP pathway in rat, which had a key role in the pathogenesis of fibrosis. These studies indicated that PRR-Hippo-YAP pathway may play crucial role in the pathogenesis of myocardial injury. In this study, we test the hypothesis that PRR may promote myocardial fibrosis by activation of YAP. The PRR knock-in and PRR conditional knock-out mice were generated to evaluate the effects of PRR-Hippo-YAP pathway on the myocardial fibrosis in mice with hypertension with diabetes. In Vitro study, cardiac fibroblast culture from PRR knock-in and PRR conditional knock-out mice was performed to assess the effects of PRR-Hippo-YAP pathway on the production of collagen protein expression, and the molecular of connective tissue growth factors (CTGF) gene expression may be regulated by PRR-Hippo-YAP pathway were evaluated. This study wants to explore the effect and mechanism of PRR-Hippo-YAP pathway on myocardial injury and fibrosis, and provide new target for treatment of myocardial injury in hypertension with diabetes.

高血压合并糖尿病早期造成心脏损伤,出现心肌纤维化，目前机制尚不十分清楚，治疗无特异性。研究已证实前肾素受体（PRR）与心血管疾病病理过程相关。我们前期研究发现高血压合并糖尿病大鼠中，PRR基因过表达激活了YAP，有研究认为Hippo-YAP通路与心肌损伤后心肌纤维化的病理过程有关。我们提出假说：PRR通过Hippo-YAP通路促进高血压合并糖尿病心肌损伤后心肌纤维化的病理过程；本研究通过构建PRR基因过表达鼠、PRR基因条件性敲除鼠，并进行体外细胞实验，论述PRR-Hippo-YAP通路在心肌纤维化中的作用，探讨PRR激活YAP的机制，进一步探讨PRR通过YAP激活结缔组织生长因子（CTGF）基因表达及促进心肌纤维化的分子机制，目的在于阐明PRR-Hippo-YAP通路在心肌损伤后心肌纤维化中的作用及意义，为高血压合并糖尿病心肌损伤后心肌纤维化治疗提供新靶点。

糖尿病是一种代谢性疾病，容易造成多种靶器官损害，可造成心脏损伤，出现心肌纤维化，从而影响心功能。但目前其发病机制尚不明确，治疗无特异性。研究表明前肾素受体（PRR）参与糖尿病及其靶器官损害的病理过程。且目前尚无研究表明YAP是否参与糖尿病心肌纤维化。我们在高血压合并糖尿病大鼠中发现，过表达PRR基因后YAP活化水平增加。基于此，我们通过构建糖尿病心肌病模型并利用PRR过表达腺病毒、PRR敲减腺病毒、YAP过表达腺病毒、YAP敲减慢病毒、YAP抑制剂，进行一系列体内及体外细胞实验，观察PRR、YAP、CTGF、TGF-β、fibronectin、Ⅰ型胶原、Ⅲ型胶原的表达及大鼠超声心动图，从而探究PRR对Hippo-YAP通路的调控作用及其参与糖尿病心肌病心肌纤维化的机制。通过实验发现，在糖尿病心肌病中，PRR及YAP表达水平升高，给予PRR过表达腺病毒后，YAP表达水平升高，而给予PRR敲减腺病毒后，YAP表达水平下降，这提示PRR是YAP的上游。给予YAP过表达腺病毒后，心肌组织的纤维化水平增加，心功能恶化，给予YAP敲减慢病毒后，发现纤维化水平下降，心功能逆转。此外，在PRR过表达基础上给予AMPK激动剂，发现YAP活化水平下降，这提示PRR通过AMPK-YAP通路参与糖尿病心肌病。这为以后糖尿病心肌病的治疗提供了新的思路和靶点。