CagA阳性幽门螺杆菌通过外泌体/SHP2调控血管内皮细胞ZO-1和VCAM-1导致动脉粥样硬化斑块不稳定

研究表明CagA阳性幽门螺杆菌（HP）感染与动脉粥样硬化性脑梗死有关，但其机制不清。我们发现：CagA阳性幽门螺杆菌感染人胃上皮细胞后，可释放含有CagA蛋白的外泌体入血，作用于血管内皮细胞，调控内皮细胞通透性和粘附能力。本项目拟采用基因敲除小鼠、透射电子显微镜、Transwell实验、单核细胞粘附实验、免疫共沉淀、免疫荧光等技术，阐明CagA阳性外泌体对斑块不稳定性的影响及分子机制，验证工作假说：①CagA阳性 HP感染释释放CagA外泌体入血，促进ApoE敲除小鼠动脉粥样硬化斑块不稳定；②CagA通过SHP-2/PAR3 /aPKC通路调控内皮细胞紧密连接蛋白ZO-1的胞内定位，导致内皮细胞屏障功能破坏；③ CagA通过SHP-2/Akt/P65通路，调控内皮细胞粘附分子VCAM-1表达，参与动脉粥样硬化斑块的不稳定。通过本项目明确CagA为抑制动脉粥样硬化斑块不稳定性的新治疗靶点。

It is reported that CagA-positive Helicobacter pylori (HP) infection is associated with atherosclerotic stroke. However, the underline mechanisms remain unclear. Our previous results showed that CagA-positive Helicobacter pylori infection induced human gastric epithelial cells to release the exosomes containing CagA protein into the blood, and the exosomes could regulate the vascular endothelial cells permeability and adhesion. In the present project, we will use gene-knockout mice, transmission electron microscopy, transwell, adhesion assay, co-immunoprecipitation and immunofluorescence staining to verify our working hypothesis. Firstly, we will verify that CagA-positive HP infection releases the CagA-containing exosomes into the blood, and promotes atherosclerotic plaque instability of ApoE knockout mice. Secondly, we will verify that CagA disturbs the location of endothelial cell tight junction protein ZO-1 by SHP-2/PAR3/aPKC signaling, which results in damaged endothelial cell barrier function. Thirdly, we will verify that CagA regulates the expression of VCAM-1 in endothelial cells by activating the SHP-2/Akt/P65 pathway, which increased the aggregation of mononuclear cells and involved in the instability of atherosclerotic plaques. This project will elucidate the molecular mechanisms of CagA-positive exosomes on plaque instability and provide a new target for the treatment of atherosclerotic plaque instability.