NHE1在netrin-1介导动脉粥样斑块巨噬细胞滞留中的作用及机制

动脉粥样硬化（AS）斑块内缺氧可导致巨噬细胞潴留。缺氧诱导神经导向因子netrin-1导致斑块内巨噬细胞潴留加剧，但具体机制有待研究。我们前期结果表明缺氧上调巨噬细胞钠氢交换体-1(NHE1)表达，但NHE1是否参与netrin-1诱导斑块内巨噬细胞潴留及机制尚不清楚。本项目拟研究AS斑块和缺氧巨噬细胞中NHE1、netrin-1二者表达及共定位规律，并在netrin-1干预条件下研究上/下调NHE1表达对巨噬细胞迁徙、群体细胞及个体细胞运动行为特征的影响；进而探讨NHE1特定功能位点（离子转运及骨架蛋白锚定）突变对细胞膜NHE1分布、细胞极化、细胞骨架改建、细胞迁徙的影响以及与RhoA/ROCK相关机制。本研究结果以期阐明NHE1参与AS斑块中缺氧介导巨噬细胞潴留的新机制，从缺氧/netrin-1/NHE1新视角为寻找AS治疗策略提供新选择，开发相关药物提供实验证据。

Hypoxia is responsible for macrophage retention in the atherosclerotic (AS) plaques. Nerve guide factor netrin-1 induced by hypoxia exacerbates AS macrophage retention, but its underlying mechanisms remain to be elucidated. Our recent observations suggest that hypoxia upregulates sodium-hydrogen exchanger 1(NHE1) expression in macrophages, but whether NHE1 participates in the response to netrin-1 and, if any, its mechanisms are unclear. To address the issues, firstly, the expression and localization of NHE1 and netrin-1 in AS plaques and hypoxic macrophages will be examined. Secondly, the population and individual mobile features as well as cell migration at the present of netrin-1 are to be determined in the transfected macrophages expressing NHE1 small interfering RNA or NHE1-EGFP fusion protein. Furthermore, the impact of NHE1 mutations (ion transport and cytoskeleton anchor sites) on NHE1 membrane distribution, cell morphological polarization, cytoskeleton reconstruction and directional migration and its RhoA/ROCK-associated mechanisms are to be investigated. The findings in this study will be reasonably expected to elucidate the new mechanism by which NHE1 is implicated in hypoxia-induced AS macrophage retention and from a new perspective of hypoxia/netrin-1/NHE1 pathway, also offer potential options in the pursuit of new AS therapeutic strategy and add experimental evidence for the development of NHE1-related drugs.