细胞外钙感受器在肺动脉高压发生发展中的作用及机制

This project is based on the latest progress made by the applicant about the importance of CaSR in mediating hypoxia-induced pulmonary vasoconstriction and pulmonary hypertension, further revealing the pivotal roles of CaSR in the pathogenesis of this disease. We propose that hypoxia and smoking induce CaSR sensitization in pulmonary artery smooth muscle cells through homodimerization and protein-protein interaction. We will also use the up-to-date strategies exploring cellular signaling cooperation that the applicant established to investigate how the calcium signal kinetics (including irregular calcium kinetics) cooperates with reactive oxygen species to control the downstream celluar events, including hypoxia and smoking induced-pulmonary vasoconstriction and pulmonary artery remodeling. Additionally, we will conduct translational studies pertaining to compounds with potential CaSR (ant)agonistic action in the treatment of pulmonary hypertension. The comprehensive experiments employing cells, isolated blood vessels, perfused lungs and intact animals as well as clinical data analysis will be expected to profoundly reveal novel mechanisms underlying the critical role of CaSR in the initiation and development of pulmonary hypertension, and provide new clues for the prevention and treatment of this disease.

本项目拟在申请人新近发现细胞外钙感受器(CaSR)介导缺氧性肺血管收缩和肺动脉高压形成的基础之上，进一步揭示CaSR发挥其关键作用的分子机理：即在缺氧和吸烟的直接与间接作用下，CaSR通过自聚合或与其他蛋白分子间的相互作用使其敏感性增强；并运用申请人所创立的研究细胞信号协同作用的新策略与技术，探讨钙信号（包括不规则钙信号）与活性氧如何协同/拮抗以共同调控肺血管收缩及肺血管改建的机制；同时，还将以CaSR为靶点完成肺动脉高压防治的相关转化研究。本项目将综合开展细胞、离体血管条、灌流肺和整体动物等系列性实验并结合临床资料分析，以期深入、完整地揭示CaSR在缺氧和吸烟所致肺动脉高压发生发展中的重要作用，为肺动脉高压发病机理提供较为系统的新理论体系，并为其预防和治疗用药提供新线索。

本项目在申请人发现细胞外钙感受器(CaSR)介导缺氧性肺血管收缩和肺动脉高压形成的基础之上，进一步揭示CaSR发挥其关键作用的分子机理：即在缺氧和吸烟的直接与间接作用下，CaSR通过自聚合或与其他蛋白分子间的相互作用使其敏感性增强，促进肺动脉高压发生发展。研究发现，急性缺氧通过CaSR胞外段129和133位点两个氨基酸形成二硫键，引起CaSR自聚合，导致CaSR敏感性增强；而慢性缺氧通过CaSR与HIMF相互作用，促进CaSR持续活化，介导缺氧肺动脉高压形成。吸烟则通过其直接或间接作用，包括香烟成份苯丙氨酸或香烟刺激产生的携带精氨的内皮微囊泡作用于CaSR，导致CaSR激活，促进肺动脉高压发生。此外，研究还发现，野百合碱通过与内皮细胞CaSR结合，诱导CaSR激活，介导肺血管内皮损伤和肺动脉高压的发生。基于上述机制研究，本项目进而开展了以CaSR为靶向的转化研究，从FDA批准的小分子药物库中筛选出了可用于防治肺动脉高压的有效药物。本项目研究较为深入、完整地揭示了CaSR在缺氧和吸烟所致肺动脉高压发生发展中的重要机制，为肺动脉高压发病机理提供较为系统的新理论体系，并为其预防和治疗用药提供了新线索。