The Role of Thrombospondins in Atherothrombosis

在后基因组时代，高通量全基因组扫描和SNP关联研究有望识别作为冠状动脉疾病（CAD）和心肌梗死（MI）重要危险因素的新基因。这些信息提出了一个新的挑战：一个已确定的基因产物是如何影响疾病的？这是GeneQuest i提出的挑战。这项针对家族性、早发性CAD/MI患者的大规模SNP病例对照研究发现了三个与MI显著相关的基因。这三个基因都是血栓反应蛋白（TSP）基因家族的成员。在单个家族中显著的基因聚类强烈暗示TSP家族与心血管病理有关，而在独立的临床研究中，TSP-2和TSP-4与MI的关联的复制和我们自己的初步数据显示，三个TSP SNP组中的每一个都显示出不同的功能，这进一步加强了这种联系。本项目将重点研究TSP-4和TSP-2。在TSP-4中，SNP导致A387 P替换，发生频率很高（在高加索人群中为34%），并使心肌梗死的风险增加近2倍。在TSP-2中，SNP是3'-非翻译区t3943g的替换，发生频率高（10%），具有保护作用（MI减少约3倍）。待验证的假设是：TSP-4和TSP-2中的snp改变了蛋白（TSP-4）或mRNA （TSP-2）的结构，从而影响了tsp的功能和/或表达。这种改变会影响血管细胞的反应，在血管壁上形成有利于或抗动脉粥样硬化的环境。为了验证这一假设，我们将：1)在分子和细胞水平上检查TSP-4和TSP-2 snp的影响；2)探索TSPs表达改变的小鼠动脉粥样硬化和血管损伤模型；3)检查正常和动脉粥样硬化的人血管中mRNA和蛋白的snp依赖性变化；4)确定SNP变异是否诱导了与其致动脉粥样硬化作用相一致的不同基因谱；5)利用心脏病患者的基因库来建立tsp与心肌梗死的其他关联

In the post-genomic era, high through put genome-wide scans and SNP association studies hold the promise of identifying new genes as significant risk factors for coronary artery disease (CAD) and myocardial infarction (MI). Such information raises a new challenge: how does an identified gene product influence disease? This was the challenge that emerged from GeneQuest I. This large-scale SNP case-control study in patients with familial, premature CAD/MI identified three gene that exhibited a significant association with MI. All three were members of the thrombospondin (TSP) gene family. The remarkable clustering of genes within a single family strongly implicates the TSP family in cardiovascular pathology, and this link is further bolstered by the replication of the TSP-2 and TSP-4 associations with MI in separate clinical studies and our own preliminary data showing that each of the three TSP SNP set displays distinct functions. This project will focus on TSP-4 and TSP-2. In TSP-4, the SNP leads to a A387 P substitution, occurs at high frequency (34% in the Caucasian population), and increases the risk of MI by almost 2-fold. In TSP-2, the SNP is a t3943g substitution in the 3'-untranslated region, occurs with high frequent (10%) and is protective (approximately 3-fold reduction in MI). The hypothesis to be tested is: the SNPs in TSP-4 and TSP-2 alter protein (TSP-4) or mRNA (TSP-2) structure, which affects the function and/or expression of the TSPs. Such alterations affect the responses of vascular cells, creating a pro- or anti-atherogenic environment in the vessel wall. To test this hypotheses, we will: 1) examine the influence of the TSP-4 and TSP-2 SNPs at a molecular and cellular level; 2) explore murine atherosclerosis and vascular injury models in which expression of the TSPs has been altered; 3) examine normal and atherosclerotic human vessels for SNP-dependent changes in mRNA and protein; 4) determine if the SNP variants induce different gene profiles consistent with their atherogenic effects; and 5) exploit the GeneBank of cardiology patients to establish additional associations of the TSPs with MI. The aggregate of these studies should provide a rigorous test of the hypothesis, extend our knowledge of the TSPs in cardiovascular disease; provide insights into their structure and function; and define general approaches to examine oathozenic mechanisms of other gene products that are linked to CAD and MI.