HIF-1α/miR-19信号轴对缺血再灌注后冠状动脉内皮功能的调控作用及机制研究

Coronary artery endothelial dysfunction enhances the susceptibility of cardiomyocytes to ischemia-reperfusion injury. Accumulating evidences indicated that miR-19 inhibits angiogenesis after vascular injury and induces arterial inflammation. Besides, miR-19 can predict prognosis of coronary artery disease. In the previous study, we found miR-19 was linked with hypoxia though HIF-1α and its level was upregulated in coronary artery endothelial cells under hypoxia/reoxygenation condition. Thus, we hypothesized that HIF-1α/miR-19 signaling axis may regulate coronary artery endothelial function after ischemia-reperfusion. To evaluate the prognostic relevance of HIF-1α/miR-19 in myocardial ischemia-reperfusion injury (MIRI), we will investigate the expression levels of HIF-1α and plasma miR-19 of acute myocardial infarction patients who underwent percutaneous coronary intervention. The cell model of oxygen-glucose deprivation (OGD)/reoxygenation will be established to explore the roles and mechanisms of HIF-1α/miR-19 signaling axis involved in the regulation of coronary artery endothelial function. Furthermore, the influence of miR-19 antagonist on repair and damage of coronary artery endothelium as well as inflammatory responses will be observed in the animal model of MIRI. This project not only reveals novel biomarkers for estimation of coronary artery endothelial function, but also provides novel targets and new ideas for prevention and cure of coronary heart disease.

冠状动脉内皮功能障碍增强心肌对缺血再灌注损伤的易感性。研究证实，富含于内皮的miR-19抑制损伤后血管生成，诱发动脉炎症，并能预测冠状动脉疾病预后。本课题组前期研究发现，冠状动脉内皮细胞在缺氧/复氧状态下表达miR-19增多，HIF-1α介导miR-19与缺氧之间的联系；提示HIF-1α/miR-19信号轴可能参与调控缺血再灌注后冠状动脉内皮功能。本项目拟检测急性心肌梗死行PCI术患者的HIF-1α和循环miR-19表达水平，评估HIF-1α和miR-19与缺血再灌注损伤及预后的关联性；构建人冠状动脉内皮细胞氧糖剥夺/复氧模型，探讨HIF-1α/miR-19信号轴对冠状动脉内皮功能的调控作用与分子机制；并进一步构建心肌缺血再灌注损伤动物模型，观察拮抗miR-19对冠状动脉内皮损伤、修复及炎症反应的影响。本项目不仅为评价冠状动脉内皮功能提供新型生物标志物，而且为冠心病防治提供新靶点与新思路。

项目的背景：冠状动脉内皮功能障碍增强心肌对缺血/再灌注损伤的易感性。缺血/再灌注过程中冠状动脉内皮细胞（CAEC）较心肌细胞和平滑肌细胞更容易遭受损伤，如果及时地对CAEC予以保护措施，能在一定程度上减轻心肌缺血/再灌注损伤。.研究内容：1）HIF-1α、miR-17~92和AhR基因多态性与糖脂代谢病易感风险之间的关联性；2）miR-324-5p对氧化应激诱导内皮祖细胞（EPC）损伤的作用及机制；3）HIF-1α/miR-19轴在缺血/再灌注致冠状动脉内皮功能障碍中的作用及机制；4）高表达miR-324-5p的EPC来源外泌体（EPC-EXmiR-324-5p）对缺氧CAEC功能的保护作用及机制；5）低氧和红景天苷联合预处理对脂肪干细胞（ASC）功能的影响及其外泌体（ASC-EX）对缺氧/复氧CAEC的保护作用；6）红景天活性成分对缺氧/复氧CAEC的保护作用及其机制；7）替格瑞洛改善心肌缺血/再灌注损伤的机制。.重要结果和关键数据：1）AhR是中国人群高血脂风险的易感基因，rs2066853位点突变有一定的预测价值；2）心肌梗死后EPC表达miR-324-5p降低是其功能障碍的重要原因，上调miR-324-5p可改善EPC功能；3）缺氧/复氧通过HIF-1α/miR-19轴靶向Atg14，抑制CAEC自噬并促进凋亡，靶向内皮过表达HIF-1α或敲低miR-19对左心功能有轻微的保护作用，联合靶向具有协同效应，说明保护冠状动脉动脉内皮有助于改善心脏功能；4）EPC-EXmiR-324-5p通过其携带的miR-324-5p保护缺氧CAEC的功能；5）低氧和红景天苷联合预处理增强ASC的抗氧化应激能力，ASC-EX主要通过调节自噬与凋亡之间的交互作用保护CAEC抵抗缺氧/复氧损伤。6）红景天苷、络思、和洛赛定三种红景天的活性成分主要通过改善氧化应激和线粒体功能抑制缺氧/复氧诱导CAEC凋亡；7）替格瑞洛通过抑制NOX4/ROS/NF⁃κB信号通路轴下调炎症因子及氧化应激水平，从而改善心肌缺血/再灌注损伤。.科学意义：本项目研究揭示了心肌缺血/再灌注后冠状动脉内皮功能障碍的分子机制和潜在干预靶点，并阐明了外泌体和药物保护CAEC改善心脏功能的作用机理，为缺血性心脏病的防治提供了新思路与理论依据。