纤毛PKD2功能紊乱促血管内皮损伤及动脉粥样硬化形成的血流动力学研究

Cilia, locates on the luminal cell surface, is a mechanosensor and conductor, and its dysfunction/disorder will lead to polycystic kidney diseases, hypertension, developmental defects and other diseases. In the prone regions of atheroscleroisis occuring at, the number and elongation of endothelial cilia were abnormally induced by athero-prone flow, such as oscillation, and reverse flow. However, whether the athero-prone flow results in the disorders of cilia mechanosensor/conductor function and its roles in enthothelial dysfuction and atherosclerosis remains unclear. Therefor,this research project will study endothelial cilia PKD2 (also named as polycystin-2,a key mechanosensor and conductor for shear stress in endothelial cells and other cells） functions on the athero-prone flow conditions, and test for the effects of the hemodynamic factors，choleaterol and IL-1 beta on cilia PKD2 functions, and its roles on enthothelial dysfuction and atherosclerosis. The project will address the following questions: Whether hemodynamic factors results in the disorders of endothelial cilia PKD2 functions? Whether the disorders of endothelial cilia PKD2 functions play a significant role in endothelial dysfunction and atherosclerosis under the athero-prone flow conditions by inhibiting the athero-protective factors，such as AMPK/KLF2, and actviting NF-kB mediated inflammation responeses? Whether cholesterol and IL-1 beta exacerbate the disorders of endothelial cilia PKD2 functions？And then, what is the mechanisms that miRNAs rugulate the endothelial cilia PKD2 functions？With these pilot studies, this project will test our hypothesis that 1) On the blood environment of athero-prone flow, hemodynamic factors enhances the expression of specific miRNAs molecules and induces the disorders of cilia PKD2 fuctions, which inhibits the action of athero-protective factors and enhances the infammation pathway，and facilitates endothelial dysfunction and inflammation; 2) Specific miRNAs take part in the response of endothelial cilia PKD2 protein to mechanical-chemical coupling signals, such as hemodynamics, cholesterol and IL-1 beta, and exacerbate the disorders of cilia PKD2 functions. Consequently, the exacerbated disorders of endothelial cilia PKD2 fuctions will promote endothelial dysfunction and atherosclerosis formation. Aiming at studying vascular impairment by the athero-prone flow, this research project will establish a framework to further understand the molecular basis of vascular biology in health and disease regulated by flow.

纤毛是细胞表面的力学感应和传导器，其功能紊乱将导致多囊肾、高血压及发育缺陷等疾病。研究发现，血流紊乱诱导的内皮细胞纤毛异常增生是动脉粥样硬化（AS）形成的基础。然而，有关血流的紊乱是否导致纤毛力学感应/传导功能的紊乱及其在AS形成中的作用却不清楚。为此，本项目以血流环境下内皮细胞纤毛PKD2蛋白功能为研究对象，确定血流动力学等因素对其功能的影响及其在内皮损伤和AS形成中的作用及机制。本项目要回答：1）血流紊乱是否导致纤毛PKD2功能紊乱及miRs机制？2) 纤毛PKD2功能紊乱是否参与单核细胞粘附等内皮功能损伤的调控及机制？3)胆固醇和炎症因子是否加重血流紊乱导致的纤毛PKD2功能紊乱及miRs机制？并验证提出的假说：在AS好发区，血流动力学等因素将参与内皮细胞miRs表达和纤毛PKD2功能紊乱的调控，抑制AMPK/KLF2等活性，并激活NF-kB等炎症途径，进而促进内皮损伤和AS形成。

纤毛是细胞表面的力学感应和传导器，其功能紊乱将导致多囊肾、高血压及发育缺陷等疾病。研究发现，血流紊乱诱导的内皮细胞纤毛异常增生是动脉粥样硬化（AS）形成的基础。然而，有关血流的紊乱是否导致纤毛力学感应/传导功能的紊乱及其在AS形成中的作用却不清楚。为此，本项目以血流环境下内皮细胞纤毛PKD2蛋白功能为研究对象，探讨了血流动力学等因素对其功能的影响及其在内皮损伤和AS形成中的作用及机制。本项目主要考察了：1）血流紊乱是否导致纤毛PKD2功能紊乱及其miRs调节的机制？2) 纤毛PKD2功能紊乱是否参内皮功能损伤的调控及相关分子机制？3)胆固醇等高危AS因子是否加重血流紊乱导致的纤毛PKD2功能紊乱及其miRs调控机制？研究结果显示，不同血流剪切力（PS和OS）作用下内皮细胞的miR-17/20a和PKD2的表达呈负相关；低振荡剪切力（PS）和胆固醇诱导的miR-17/20a可靶向PKD2基因3’ UTR端，抑制PKD2基因和蛋白的表达，进而诱发血管内皮损伤和炎症反应。验证了本课题提出的假说：在AS好发区，血流动力学等因素将参与内皮细胞miRs表达和纤毛PKD2功能紊乱的调控，抑制AMPK/eNOS等活性，并激活炎症反应途径，进而促进内皮损伤和AS形成。本项目的研究，试图探寻AS发生发展中内皮细胞纤毛的力学调控解释，为其病变机制研究和治疗方式及提供了新的思路。