ACE2-Ang(1-7)-Mas轴在肺血管重构过程中的内皮保护机制

A new discovered axis in rennin-angiotensin-system consisting of angiotensin-converting enzyme 2(ACE2), angiotensin(1-7)[Ang(1-7)] and its specific receptor Mas counterregulates the effect of traditional ACE-Ang II-Ang II receptor 1(AT1R) axis, which is believed to play an protective role in the development of pulmonary arterial hypertension. In addition, in our recent research, we found that ACE2 activation prevented and partial reversed proliferative vascular remodeling in pulmonary circulation. Endothelial dysfunction and abnormal apoptosis are key mechanisms in the pathogenesis of pulmonary vascular remodeling, a critical signaling branch downstream of G-protein coupled receptor, Hippo signaling pathway, probably participates in the process of endothelial function, and Mas is one kind of G-protein coupled receptor. Therefore, we hypothesize that ACE2-Ang(1-7)-Mas axis attenuates pulmonary vascular remodeling through Hippo signaling pathway affecting endothelial function and apoptosis of endothelial cell in the development of pulmonary arterial hypertension. The hypothesis will be confirmed by both animal and cell experiment. First, severe pulmonary arterial hypertension is induced by monocrotaline injection following left pneumonectomy in rats, and then the rats treated by ACE2 activator and/or inhibitor. The expression of the component in rennin angiotensin system, pulmonary arterial pressure, pathological change, endothelial function and the expression of components in Hippo signaling pathway will be investigated to explore the mechanism of ACE2-Ang(1-7)-Mas in this process. Second, the primary cultured pulmonary endothelial cell from rats developing pulmonary arterial hypertension will be obtained, and the cells will be treated by ACE2 activator and inhibitor. The proliferation, apoptosis, migration, microtubule formation and the change of Hippo signaling pathway will be detected for further exploring the mechanism of this axis. Finally, the mechanisms of Hippo signaling pathway in this process was confirmed by gene transfection and knock out of YAP and LATS1 in endothelial cell. The present research will further improve the physiopathologic mechanisms of ACE2-Ang(1-7)-Mas axis in the process of pulmonary vascular remodeling and provide the evidence of ACE2 as a target for the treatment of pulmonary arterial hypertension.

血管紧张素转化酶2(ACE2)-血管紧张素(1-7)[Ang(1-7)]-Mas轴是肾素血管紧张素系统新发现的调节轴，拮抗ACE-AngII-AT1R轴的作用。近年发现该轴在肺动脉高压(PAH)形成过程中起保护作用，我们研究发现ACE2激活可抑制和部分逆转肺血管增殖性病变。内皮功能和凋亡是PAH的关键机制，Hippo信号通路可能参与内皮功能调节，且是G蛋白偶联受体的下游关键信号通路，Mas即属于G蛋白偶联受体。本研究激活ACE2干预PAH模型，检测上述两个调节轴的变化、肺血管病变程度、内皮功能、内皮凋亡和Hippo通路主要成分；原代培养PAH大鼠肺动脉内皮细胞，ACE2激活剂干预，检测内皮细胞增殖、凋亡、迁移、微管形成和Hippo通路主要成分，基因转染和敲除这一通路关键成分LATS1，YAP，明确该通路参与ACE2改善内皮功能和凋亡的机制，完善其病理生理机制，为药物开发提供理论依据。

肺动脉高压(pulmonary arterial hypertension, PAH)是多种病因引起的致死性疾病，发病机制复杂，至今尚未完全清楚，可能涉及基因突变、血管活性物质失衡、细胞功能损伤、自身免疫反应等多个途径，肺血管重构是其主要的病理机制。近年发现的血管紧张素转化酶2(angiotensin converting enzyme 2,ACE2)-血管紧张素(1-7)[angiotensin(1-7), Ang(1-7)]-Mas调节轴被认为在肺动脉高压的病理生理过程中起保护作用，成为肺动脉高压靶向治疗的新希望，但相关研究非常有限，其作用机制尚不明确。.本课题首先以野百合碱注射联合左肺切除建立的重度肺动脉高压大鼠为研究对象，实验中通过检测持续注射Rec对肺动脉内皮依赖的舒张功能、肺组织NO水平、eNOS表达水平、磷酸化eNOS-Ser1177和磷酸化eNOS-Thr495表达水平，进一步研究ACE2激活改善内皮细胞功能抑制肺血管重构的机制。其次选择野百合碱联合肺叶切除构建重度肺动脉高压模型，及内皮细胞实验，并给与相应的药物干预，通过观察血流动力学指标，右心室肥厚程度，肺小动脉的重构及细胞凋亡情况，Hippo通路成分的改变，内皮细胞凋亡情况研究ACE2激活对肺动脉内皮细胞凋亡和Hippo通路的影响，探讨ACE2在重度肺动脉高压发展过程中对血管重构的可能保护机制。评价ACE激活对重度肺高压肺动脉内皮细胞的促凋亡作用及机制，为ACE2临床应用于肺动脉高压治疗提供实验依据，为逆转肺血管重构提供了新途径。