The Role of Thrombospondins in Atherothrombosis

在后基因组时代，高通量全基因组扫描和SNP关联研究有望确定新的基因是冠状动脉疾病(CAD)和心肌梗死(MI)的重要危险因素。这样的信息提出了一个新的挑战：已识别的基因产物如何影响疾病？这就是GeneQuest I提出的挑战。这项针对家族性早产儿CAD/MI患者的大规模SNP病例对照研究确定了三个与MI显著相关的基因。这三人都是凝血酶敏感蛋白(TSP)基因家族的成员。单个家族基因的显著聚集性强烈表明TSP家族与心血管病理有关，而在单独的临床研究和我们自己的初步数据显示，三个TSP SNP集合中的每一个都显示出不同的功能时，这种联系进一步得到了TSP-2和TSP-4与MI关联的复制的支持。该项目将侧重于TSP-4和TSP-2。在TSP-4中，SNP导致A387P替换，发生频率很高(在高加索人群中为34%)，并使MI的风险增加近2倍。在TSP-2中，SNP是3‘-非翻译区的t3943G替换，出现频率很高(10%)，并且具有保护性(MI大约减少3倍)。需要检验的假设是：TSP-4和TSP-2中的SNP改变蛋白质(TSP-4)或信使核糖核酸(TSP-2)的结构，从而影响TSP的功能和/或表达。这种改变会影响血管细胞的反应，在血管壁上创造一个有利于或反对动脉粥样硬化的环境。为了验证这些假设，我们将：1)在分子和细胞水平上检测TSP-4和TSP-2 SNPs的影响；2)探索TSP-4和TSP-2 SNPs表达发生改变的小鼠动脉粥样硬化和血管损伤模型；3)检测正常和动脉粥样硬化患者血管中SNP依赖的mRNA和蛋白质的变化；4)确定SNP变体是否诱导与其致动脉粥样硬化作用一致的不同基因谱；以及5)利用心脏病患者的基因库，建立TSP与MI之间的更多关联。这个 这些研究的总和将为这一假说提供严格的检验，扩展我们对TSP在心血管疾病中的知识；提供对其结构和功能的见解；并确定检查与CAD和MI相关的其他基因产物的致卵机制的一般方法。

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.