Identification of Genes Influencing Total Antioxidant Status

描述(由申请者提供)：这个项目将采用一种新的方法来经验地识别影响总抗氧化状态的候选基因，总抗氧化状态是与心血管疾病风险相关的氧化应激指数。使用从圣安东尼奥家庭心脏研究中1,240名墨西哥裔美国人的淋巴细胞样本中获得的现有定量转录图谱，我们已经识别了大约1,400个转录本，这些转录本从定量连锁分析中推断出显示出非常重要的顺式调控证据。这些顺式调控的转录本中的每一个都已被检查是否与TAS水平有关。利用这些大规模的全基因组表达数据，我们发现了大约150个受顺式调控的基因，这些基因也与TAS水平显著相关。拟议的项目将利用这种全基因组表达的信息来快速识别影响这些新的经验性选择的候选基因转录水平的调控序列变体，并评估它们对人类血浆总抗氧化状态的影响。为了确定与心血管疾病风险相关的氧化应激相关基因，我们将检验75个新的经验性选择的候选基因。我们的顺式作用序列变异的先前证据可以被用作概率因果锚，以最大限度地增加我们在所选基因的近端启动子内发现功能变异的机会。对于每个基因，我们将(1)重新测序182名创始人中约2个千碱基对的潜在启动子区域，以确定启动子变异；(2)在我们拥有转录谱的1,240个SAFHS样本中，对所有检测到的启动子变异进行基因分型；(3)检测启动子序列变异是否与适当候选基因的基因表达水平相关；(4)检测启动子序列变异与血浆总抗氧化剂水平之间的关联；(5)确认在墨西哥裔美国人家庭中观察到的与总抗氧化剂水平的关联；以及(6)对影响TAS水平的启动子变异进行初步的功能分析。这项拟议的研究应该会加快发现新基因的速度，这些基因是人类适应氧化应激与心血管风险相关的变异的基础。通过关注那些转录产物显示顺式调节变异和与抗氧化状态密切相关的基因，我们应该最大限度地增加发现影响心血管疾病风险的因果遗传变异的可能性。公共卫生相关性：动脉粥样硬化是北美死亡的主要原因，据预测，在未来20年内，全球范围内的动脉粥样硬化将达到类似的区别。在这个项目中，我们将采用一种新的策略，该策略应该会加快发现与心脏病风险有关的基因的速度。对一些与这种疾病易感性有关的基因的了解将有助于我们理解动脉粥样硬化的原因，并有可能加速寻找新的治疗方法。

DESCRIPTION (provided by applicant): This project will employ a novel approach to the empirical identification of candidate genes influencing total antioxidant status, an index of oxidative stress that is related to cardiovascular disease risk. Using existing quantitative transcriptional profiles obtained from lymphocyte samples from 1,240 Mexican American individuals in the San Antonio Family Heart Study, we have identified approximately 1,400 transcripts that exhibit highly significant evidence for cis-regulation as inferred from quantitative linkage analysis. Each of these cis-regulated transcripts has been examined for association with TAS levels. Using this large-scale genome-wide expression data, we have discovered approximately 150 cis-regulated genes that also are significantly correlated with TAS levels. The proposed project will exploit this genome-wide expression-based information to rapidly identify regulatory sequence variants that influence transcriptional levels of these novel empirically-chosen candidate genes and to assess their influence on human plasma total antioxidant status. In order to identify genes involved in oxidative stress that are relevant to cardiovascular disease risk, we will examine 75 novel empirically-chosen candidates. Our prior evidence for cis-acting sequence variation can be exploited as a probabilistic causal anchor to maximize our chance for finding functional variation within the proximal promoters of the chosen genes. For each gene, we will (1) resequence approximately two kilobases of putative promoter region in 182 founder individuals to identify promoter variants; (2) genotype all detected promoter variation in the 1,240 SAFHS samples for which we have transcriptional profiles; (3) test whether promoter sequence variants are associated with gene expression levels of the appropriate candidate gene; (4) test for associations between promoter sequence variants and plasma total antioxidant levels; (5) confirm observed associations with total antioxidant levels in an independent sample of Mexican American families; and (6) perform preliminary functional analyses of promoter variants influencing TAS levels. The proposed research should increase the pace of discovery of novel genes underlying human variation in accommodation of oxidative stress in relation to CVD risk. By focusing on genes whose transcripts show evidence for both cis-regulatory variation and a strong relationship with antioxidant status, we should maximize our probability for finding causal genetic variants influencing CVD risk. PUBLIC HEALTH RELEVANCE: Atherosclerosis is the leading cause of mortality in North America and is predicted to attain a similar distinction on a global scale within the next twenty years. In this project, we will employ a novel strategy that should increase the pace of discovery of genes that are involved in heart disease risk. Such knowledge of some of the genes involved in susceptibility to this disease will contribute to our understanding of the causes of atherosclerosis and potentially speed the search for new treatments.