肺炎衣原体借助TLR2/HS“共受体”入侵血管平滑肌细胞进而促进动脉粥样硬化形成

项目名称： 肺炎衣原体借助TLR2/HS“共受体”入侵血管平滑肌细胞进而促进动脉粥样硬化形成

项目编号： No.81470551

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 医药、卫生

项目作者： 张丽莙

作者单位： 天津医科大学

项目金额： 73万元

中文摘要： 肺炎衣原体（C.pn）感染与AS关系密切，但机制不清。TLR2和硫酸乙酰肝素（HS）均对AS发病起重要作用，且后者可与膜受体形成共受体来介导微生物入侵细胞。前期研究发现C.pn感染VSMC及引起其迁移功能改变与TLR2密切相关，故推测C.pn可能借助TLR2/HS共受体入侵VSMC并促进其迁移进而参与AS发病。我们拟从细胞水平：免疫共沉淀确定TLR2与HS之间的相互作用；分别改变TLR2和HS表达或共表达TLR2和HS，检测C.pn感染率和细胞迁移能力。动物水平：C.pn分别感染TLR2缺陷和HS高表达的小鼠，或降低TLR2缺陷小鼠的HS表达或抑制HS高表达小鼠的TLR2功能后行感染，观察主动脉内VSMC感染情况；五色套染法评价AS病变程度。由此，确证TLR2/HS共受体介导C.pn入侵VSMC并促进AS发病。研究结果将阐明C.pn入侵VSMC及其导致AS的分子机制，提供防治AS的新靶点。

中文关键词： 肺炎衣原体；入侵；血管平滑肌细胞；Toll样受体2；硫酸乙酰肝素

英文摘要： Although accumulating evidence indicates that Chlamydia pneumoniae (C.pn) infection is closely associated with atherosclerosis (AS), the exact mechanisms for C.pn infection-induced AS remain unclear. Toll-like receptor 2 (TLR2) and heparan sulfate (HS) have been shown to play important roles in the development of AS. And HS requires the membrane receptor as a co-receptor for successful invasion of some microorganisms into their host cells. Our preliminary results showed that TLR2 is closely related to C.pn infection of vascular smooth muscle cells (VSMCs) and the subsequent changes in VSMC migration ability. Therefore, we hypothesize that TLR2/HS co-receptor is required for C.pn's invading into VSMCs and promoting cell migration, thereby leading to the development of AS. Accordingly, our research will be carried out in the following two aspects: at the cellular level, co-immunoprecipitation assay will be used to determine the interaction of TLR2 with HS in the infected VSMCs; Then the entry of C.pn into cells and the ability of cell migration will be detected after HS and TLR2 are respectively upregulated and downregulated, or after HS and TLR2, either alone or in combination, are overexpressed. At the whole-animal level, the TLR2 knockout mice and the HS-overexpressing mice will be both inoculated with C.pn, and then the number of C.pn inclusions in the mouse aortic VSMCs will be determined; After the downregulation of the HS expression in TLR2 knockout mice or suppression of TLR2 activation in HS-overexpressing mice, C.pn inclusions in the mouse aortic VSMCs will be detected, and then histological staining with the Movat's pentachrome stain will be used to measure the areas of the AS lesions in the aorta. Thus, TLR2/HS co-receptor will be demonstrated to mediate the entry of C.pn into VSMCs, and then promote the development of AS. Our research findings will not only present a new molecular mechanism by which C.pn invades into VSMCs, and then results in the initiation of AS, but also provide a new target for preventing AS.

英文关键词： Chlamydia pneumoniae;Invasion;Vascular smooth muscle cell;Toll like receptor 2;Heparan sulfate