ADAM17对糖尿病心肌纤维化的影响及其分子机制研究

In an attempt to explore the effects and underlying molecular mechanisms of ADAM17, a new member of renin-angiotensin system, on diabetes-induced myocardial fibrosis, the following in vitro and in vivo experiments were designed: the effects of ADAM17 gene overexpression and interference on the expression of old and new members of RAS will be studied in vitro with the purpose to clarify the molecular mechanisms of the role of ADAM17 in participating the network regulation of RAS; the effects and underlying molecular mechanisms of ADAM17 gene overexpression and interference on the transdifferentiation from fibroblasts to myofibroblasts in diabetes will be investigated in vitro and in vivo; the impact of ADAM17 gene overexpression and interference on left ventricular remodeling and function, the extent of myocardial fibrosis and myofibroblast trandifferentiation, and expression of intracellular signaling-related proteins will be observed in a rat model of diabetic cardiomyopathy to clarify the effects and underlying mechanisms of ADAM17 gene intervention on diabetes-induced myocardial fibrosis; the effects of ADAM17 gene interference and the combination of ADAM17 gene interference with angiotensin-converting enzyme inhibitor, angiotensin receptor blocker, angiotensin 1-7 or aldosterone antagonist on left ventricular remodeling and function, the extent of myocardial fibrosis and its related biomarker expression, and the expression of new and old members of RAS will be examined in a rat model of diabetic cardiomyopathy in order to elucidate the synergistic effects of ADAM17 gene interference with known therapeutic targets of RAS on diabetes-induced myocardial fibrosis. This research program will provide a new avenue to further understanding the pathogenesis and defining novel therapeutic targets of diabetes-induced myocardial fibrosis.

为了探讨肾素-血管紧张素系统（RAS）新成员ADAM17对于糖尿病心肌纤维化的影响及其分子机制，本课题拟在体外实验中，探讨ADAM17基因过表达和干扰对于RAS新老成员表达的影响及分子机制；在体外和体内试验中，探讨ADAM17基因过表达和干扰对于糖尿病状态下成纤维细胞向肌成纤维细胞转化的作用及其分子机制；在糖尿病性心肌病大鼠模型中，探讨ADAM17基因过表达和干扰对于左室重构和功能、心肌纤维化程度、肌成纤维细胞转分化和细胞内信号通路相关蛋白的影响及其分子机制；探讨单纯ADAM17基因干扰和ADAM17基因干扰与ACEI、ARB、AA或Ang 1-7 合用对于左室重构和功能、心肌纤维化程度及其信号蛋白表达、心肌RAS成员表达的影响，明确ADAM17 抑制与RAS已知治疗靶点联合对于糖尿病心肌纤维化的协同作用。本课题将为进一步阐明糖尿病心肌纤维化的发生机制和干预靶点提供新的途径。

为了阐明肾素-血管紧张素系统（RAS）新成员ADAM17对于糖尿病心肌纤维化的影响及其分子机制，本课题首先探讨了高糖刺激下ADAM17基因过表达和干扰对于RAS系统的调控作用和分子机制，证实ADAM17过表达和抑制可调控高糖刺激下小鼠原代心肌成纤维细胞的ACE2水平，ADAM17抑制可调控高糖刺激下大鼠心肌细胞的ACE2水平。继而研究了ADAM17过表达和干扰对于糖尿病状态下成纤维细胞向肌成纤维细胞转化的作用及其分子机制，发现ADAM17干扰可有效抑制高糖刺激下肌成纤维细胞的转分化，ADAM17通过TGF-β1/Smad3通路调节糖尿病性心肌病小鼠肌成纤维细胞的转分化，ADAM17干扰通过上调心肌ACE2并下调AT1R而改善糖尿病性心肌病小鼠心功能和心肌纤维化。构建了特异性敲除心肌细胞ADAM17基因的小鼠模型，完成了ADAM17基因敲除对糖尿病性心肌病小鼠模型心功能和心肌纤维化影响和机制的研究，证实特异性敲除心肌细胞ADAM17改善糖尿病性心肌病小鼠心功能、心肌纤维化和细胞凋亡，上调糖尿病小鼠心肌ACE2和激活AMPK/TFEB信号通路，并调节自噬平衡。完成了ADAM7 干扰与ACEI类药物培哚普利、ARB类药物氯沙坦、醛固酮受体拮抗剂（AA）依普利酮或Ang-(1-7)联合干预对糖尿病心肌纤维化影响和机制的体内研究，明确了ADAM17 抑制与RAS已知治疗靶点联合对于糖尿病心肌纤维化的协同作用。结果证实，ADAM17抑制和ACEI或ARB对改善糖尿病小鼠心功能和心肌纤维化无协同作用，而ADAM17抑制和Ang-(1-7)或依普利酮可协同改善糖尿病小鼠心肌纤维化。本课题为进一步阐明糖尿病心肌纤维化的发生机制和干预靶点提供了新的途径。ADAM17抑制联合Ang-(1-7)或依普利酮可能协同改善心肌重构和心力衰竭。