PEAR1基因多态性对蛋白表达及服用替格瑞洛患者的血小板聚集功能的影响

Anti-platelet drugs are the critical medicines for patients with coronary heart disease. However, on-treatment platelet reactivity varies a lot among patients with anti-platelet therapy, leading to ischemic events or bleeding. Thus it is significant to study possible mechanism and factors which lead to the individual differences of on-treatment platelet reactivity. Our earlier research suggested that platelet endothelial aggregation receptor-1 (PEAR1) gene polymorphisms and its haplotypes are associated with on-treatment platelet reactivity and ischemic events. However, the possible mechanism is unclear. Based on the previous research, we focus on PEAR1 protein expression for further research. We plan to select 16 single nucleotide polymorphisms of PEAR1, establish the steric structure of PEAR1 for the first time and predict the possible impact of gene polymorphisms and haplotypes on PEAR1 protein function. We plan to detect the protein expression of PEAR1 in patients with stable coronary heart disease before and after ticagrelor therapy. At the same time, we use specific methods and lab index to evaluate platelet aggregation induced by TXA2 and ADP. We aim to estimate the association between PEAR1 gene polymorphisms and protein expression, and estimate the association of gene polymorphisms and platelet aggregation, to further explain the relationship of PEAR1 gene polymorphisms and antiplatelet therapy. The results of this study might help to provide evidence for illuminating the interaction between PEAR1 and antiplatelet therapy, and might shed some light on new target discovering of antiplatelet therapy in the future.

抗血小板药物是冠心病患者药物治疗的核心，但用药后患者残余血小板功能存在较大个体差异，导致不良事件发生，探索该个体差异的发生机制和影响因素具有重要意义。本课题组前期研究提示，血小板内皮聚集受体（PEAR1）基因多态性及其单体型与冠心病患者不良缺血事件显著相关，但相关机制尚不明确，本项目拟从基因突变和蛋白表达的角度推进机制探索研究。本项目拟系统筛选16个PEAR1多态性位点、进行单体型分型，构建蛋白立体结构模型并预测基因多态性对蛋白功能与立体结构影响；同时在冠心病人群中检测替格瑞洛给药前、后患者血小板PEAR1蛋白的表达量，并且选择特异性的方法评价血栓素A2和二磷酸腺苷诱导的血小板聚集功能，通过关联分析探索PEAR1基因多态性对蛋白表达的影响及基因多态性、蛋白表达对血小板聚集功能的影响，进一步阐明PEAR1与抗血小板药物治疗的关系，为优化抗血小板药物治疗、寻找治疗新靶点提供思路。

血小板内皮聚集受体(PEAR1)编码基因PEAR1多态性与冠心病患者不良缺血事件显著相关，但与现有抗血小板治疗相关性尚不明确，尤其缺乏患者人群的探索研究。本研究建立了157例冠心病患者研究样本库，从PEAR1基因多态性、甲基化水平和PEAR1蛋白结构的角度探索其与冠心病患者血小板表面PEAR1蛋白水平的相互关系，并且探索EAR1蛋白水平与已有抗血小板治疗药物靶点受体花生四烯酸（AA）通道和二磷酸腺苷（ADP）通道的相关性，探索PEAR1对抗血小板药物治疗的可能影响。结果显示，PEAR1基因16个tagSNP对蛋白结构无显著影响，但PEAR1rs12041331GG基因型患者血小板表面PEAR1蛋白水平有高于GA/AA基因型患者的趋势，进一步探索PEAR1甲基化对蛋白水平影响，发现PEAR1基因甲基化岛1甲基化水平与PEAR1蛋白水平显著相关。对PEAR1蛋白与血小板活化上游受体通路关联性探索分析发现，在冠心病患者人群中，血小板PEAR1水平与患者白细胞计数以及阿司匹林作用途径AA通路TXA2水平相关，而与P2Y12受体抑制剂作用途径ADP受体通路特异性血小板反应性并无显著相关性，提示PEAR1作用可能与炎症因子存在相互作用。此外本研究发现TXA2水平显著受ITGA2基因多态性影响，ITGA2基因rs1126643 CC基因型的患者TXB2蛋白水平显著低于CT/TT基因型的患者。本研究结果提示，备受关注的新型血小板跨膜蛋白PEAR1水平与P2Y12受体抑制剂作用通路并无相关性，与炎症因子相关。更值得关注的是，PEAR1蛋白及患者用药后血小板功能与PEAR1基因甲基化水平显著相关，提示PEAR1蛋白可能是独立于现有抗血小板药物的新靶点，这为未来优化冠心病患者抗血小板药物治疗、寻找治疗新靶点提供思路。