CFTR氯通道在血小板介导动脉血栓中的作用和机制

血小板激活诱发的动脉血栓形成是防治动脉血栓性疾病的重要药物靶标。预实验发现冠脉疾病患者外周血血小板CFTR氯通道蛋白表达显著降低，引起胞浆氯离子浓度异常升高，氯敏感激酶SGK1磷酸化显著增加；CFTR基因敲除小鼠显著促进氯化铁诱导的肠系膜动脉血栓形成，血小板磷酸化SGK-1和膜受体P2Y12/PAR4表达上调，促进血小板聚集和释放；CFTR氯通道抑制或基因敲除使血小板氯外流减少，胞浆氯离子浓度因此升高。本项目拟应用血小板特异性CFTR基因敲除/敲入小鼠等方法，探讨CFTR氯通道调控的胞浆氯离子浓度改变，经SGK1激酶介导，影响血小板激活和动脉血栓形成的作用及分子机理。本研究将为阐明CFTR氯通道是调控血小板功能和动脉血栓形成的一个早期负性调控分子的新观点，并为寻找防治动脉血栓性疾病和抗血栓药物新靶点提供线索。

The arterial thrombosis resulted from platelet activation and aggregation is an important drug target against arterial thrombotic disease, such as coronary artery disease (CAD) and ischemic stroke. Our preliminary data found that peripheral circulating platelets from CAD patients displayed abnormally decreased CFTR chloride channel protein expression, increased intracellular chloride concentration([Cl-]i) and elevated SGK1 phosphorylation level. In FeCl3-induced mesenteric arteriole thrombosis mouse model, CFTR gene deletion and selective CFTR inhibitor increased platelet [Cl-]i and SGK1 phosphorylation, upregulated P2Y12/PAR4 protein expression and ADP or thrombin-induced platelet aggregation and release, resulting in the accelerated thrombosis formation in vivo. This project will intend to elucidate that the enhanced CFTR-dependent platelet [Cl-]i will stimulate the phosphorylation of Cl- sensitive kinase SGK-1, which will accelerate arterial thrombosis formation via a positive P2Y12/PAR4 and its downstream platelet aggregation pathway. The PF4-cre CFTR knockout and transgene mice arterial thrombosis model will be applied to identify the important role of CFTR-dependent [Cl-]i in platelet-mediated thrombosis and the underlying mechanisms. This study will clarify the new function of platelet CFTR, and propose a perspective that CFTR chloride channel is an important negative regulator of the formation of arterial thrombosis in arterial thrombotic disease. This project will also provide important evidence to identify CFTR as a new potential target of antithrombotic treatment.