DDAH1在肺动脉高压中的作用及靶向机制研究

Previous clinical studies have demonstrated that ADMA is associated with PAH, however, the mechanism remains unclear. We have demonstrated that DDAH1 plays the essential role for degrading endogenous nitric oxide synthase inhibitor ADMA. We have also demonstrated that DDAH1 is highly aboundant in vascular endothelium and DDAH1-KO mice has spontaneously developed mild PAH. Therefore, we hypothesized that DDAH1 plays an important role in attenuating PAH development and DDAH1 dysfunction can cause or facilitate PAH development through increasing pulmonary vascular ADMA and decreasing eNOS. Using three gene deficient mice of DDAH1-KO, DDAH1-tg and eNOS-KO,we will investigate the DDAH1/ADMA/eNOS pathway on lung tissue and vascular endothelium, combining hypoxia-induced PAH and the technique of endothelial cell culture. In addition, hemodynamic methods, histomorphology and molecular biology will be also used to demonstrate the protection effect of DDAH1 on lung and vascular endothelium. Overall, our research will explore unique new knowledge defining the causal role of DDAH1 dysfunction in PAH development, and the novel molecular mechanism by which DDAH1 and identify DDAH1 as a therapeutic target for protecting lung from PAH.

非对称性二甲基精氨酸(ADMA)是内源性一氧化氮合酶（NOS）抑制剂，血浆ADMA水平升高，损伤内皮细胞，增加肺动脉高压（PAH）发病率，但机制不清。我们前期工作发现：① 二甲基精氨酸二甲胺水解酶1（DDAH1）是ADMA的主要降解酶，在肺血管内皮细胞高度表达；② DDAH1-KO小鼠自发轻度肺动脉高压。据此，我们认为DDAH1调控ADMA及其下游靶蛋白eNOS，促使肺动脉内皮细胞功能异常，导致肺动脉高压。本项目拟采用DDAH1-KO、DDAH1-tg与eNOS-KO三种转基因小鼠，结合低氧性肺动脉高压模型与内皮细胞培养技术，运用血流动力学、组织形态学、分子生物学等方法，通过研究肺组织与动脉内皮细胞DDAH1/ADMA/eNOS通路，阐述DDAH1维护肺动脉内皮细胞正常功能的机制。本研究对揭示DDAH1/ADMA/eNOS通路在肺动脉高压中的作用具有重要意义，为治疗肺动脉高压奠定基础。

第一部分.背景：非对称性二甲基精氨酸(ADMA)是内源性一氧化氮合酶（NOS）抑制剂，血浆ADMA水平升高，损伤内皮细胞，增加肺动脉高压（PAH）发病率，但机制不清。.主要研究内容：本项目采用DDAH1-KO转基因小鼠，结合低氧性肺动脉高压模型与内皮细胞培养技术，运用血流动力学、组织形态学、分子生物学等方法，通过研究肺组织与动脉内皮细胞DDAH1/ADMA/eNOS通路，阐述DDAH1维护肺动脉内皮细胞正常功能的机制。.结果与关键数据：小鼠DDAH1基因敲除后出现轻度肺动脉高压与高血压，在低氧应激情况下加重氧化应激，抑制eNOS活性，ADMA生成增加，促进了肺动脉高压的发生发展。.科学意义：本研究对揭示DDAH1/ADMA/eNOS通路在肺动脉高压中的作用具有重要意义，为治疗肺动脉高压探索新的方向。.第二部分：.运用基因工程小鼠，结合细胞与小鼠心肌肥厚模型（AB）等，先后探索了GAS6、SNIP1等蛋白在心肌肥厚中的作用机制，研究结果充分阐明了GAS6、SNIP1在小鼠心肌肥厚中具有重要的调控作用。发表了3篇SCI文章。培养了4位研究生。