冠心病新相关基因ESYT3的功能鉴定

We identified ESYT3 as a novel susceptibility gene for coronary artery disease (CAD) for the first time, which is associated with female Chinese Han population. Further study demonstrated its high expression in cells that are functionally linked to the pathogenesis of CAD, including vascular endothelial cell, smooth muscle cell, and lymphocyte. Increased expression of ESYT3 was found in lymphocytes from patients of CAD. However, the mechanism of ESYT3 in genesis of CAD is unknown. This study aims to investigate: 1) cellular function of ESYT3 in vascular endothelial cell, smooth muscle cell, and lymphocyte. By over-expression and knockdown of ESYT3 in lymphocyte, vascular endothelial cell, and smooth muscle cell from female SD rat, we intend to study the role of ESYT3 in adhesion of lymphocyte, NO generation of endothelial cell, and proliferation, apoptosis, migration of endothelial cell and smooth muscle cell; 2) signaling pathway of ESYT3. Using whole genome gene expression chip and candidate gene pathway analysis, we propose to find out genes involved in ESYT3 signaling pathway; 3) validation of the mechanism of ESYT3 involved in atherosclerosis in vivo by applying female ApoE knockout mice; 4) genes involved in ESYT3 signaling as novel candidate CAD susceptibility genes by population association study. Our study will characterize the function and mechanism of ESYT3 in the pathogenesis of CAD, thus providing novel therapeutic targets and new insights into prediction, prevention and personal medication of CAD.

ESYT3是我们发现的新的冠心病易感基因，与中国汉族女性人群冠心病相关，我们进一步研究发现其在血管内皮和平滑肌细胞以及淋巴细胞中高度表达，冠心病人淋巴细胞中表达增加，上述细胞是动脉粥样硬化发生、发展的重要基础，ESYT3如何通过影响这些细胞的功能进而参与冠心病的发生尚不清楚。本项目拟研究：1）以SD大鼠的血管内皮细胞、平滑肌细胞和淋巴细胞为模型，通过过表达和敲低ESYT3研究其在淋巴细胞粘附，内皮细胞NO生成及内皮和平滑肌细胞的增殖、凋亡、迁移过程中的作用；2）通过该基因过表达芯片和候选基因分析，确定2-3个该基因直接上下游信号分子；3）在ApoE敲除小鼠模型中验证ESYT3参与动脉粥样硬化损伤的机制；4）通过群体遗传学研究ESYT3上下游基因作为冠心病新候选基因的可能性。本研究有助于阐明ESYT3功能及其参与冠心病的发病机制，为冠心病预测、预防、个体化治疗及新药靶点的研发提供新的依据。

全基因组关联研究（GWAS）报道的与冠心病相关的位点，绝大多数还未经进一步的精细定位和功能研究证实，所以在不同人群中证实这些位点的真实性并精细定位到致病的基因和功能变异，鉴定它们的功能，这是GWAS成果应用于分子诊断和疾病治疗至关重要的一步。染色体12q24.1是GWAS报道的一个新的冠心病易感位点，我们完成了一项涉及北京、沈阳、哈尔滨三个城市人群的冠心病病例-对照关联研究（3532 case/3544 control），对该染色体位点进行了与冠心病相关的精细定位、imputation及eQTL和进一步的Knockdown功能研究筛选冠心病的易感基因。我们首次发现了一个新的东亚人群特有的block（block2）与冠心病相关，同时验证了一个之前报道过的block（block1）。Block1上单倍型ATGGG和GCACA的OR值分别为0.79 (0.72-0.86, 8.358×10-8)和1.24 (1.13-1.36, 2.576×10-6)；block2上的单倍型GA和AG的OR值分别为1.22 (1.14-1.30, 6.484×10-9)和 0.82 (0.77-0.88, 6.484×10-9)。其中block2上的两个保护性index SNP减少基因X的表达（p=0.034），但对block2上其他基因的表达没有影响。进一步的功能证据显示基因X可能是与中国人群冠心病相关的候选基因。本研究的顺利完成，对冠心病遗传学领域中有关遗传异质性难点的研究提供了思路，本研究的发现对冠心病的筛查、预测和预警，早期诊断和个体化防治以及新药物靶点的研发提供了新的依据。