Systems Genetics of Vascular Smooth Muscle Phenotypes

项目摘要 冠状动脉疾病（CAD）仍然是西方世界的主要死亡原因，尽管有显著的 在早期发现和广泛使用降脂和抗高血压药物方面取得进展。到目前为止，没有一个 已经开发了一种针对血管壁中的原发性疾病过程的药物。的完整理解 因此，迫切需要开发其他治疗方法。的常见形式 动脉粥样硬化涉及环境因素，数百种遗传变异及其相互作用， 其对疾病易感性的影响相对较小。最新的全基因组关联研究 （GWAS）在近65万人中确定了175个与 增加CAD风险。然而，大多数潜在的基因和相关机制如何这些 导致疾病过程的变异仍然未知。该提案概述了一个综合遗传学 从151个基因型多位点分离的人主动脉平滑肌细胞（SMC）的独特资源研究 种族心脏移植供体，以发现CAD相关的变异，干扰SMC基因表达， 其下游功能性后果。在最近的研究中，我们测量了静止期和静止期的基因表达， 增殖培养条件代表SMC从健康向动脉粥样硬化的转分化 表型。我们鉴定了84个基因，其表达与GWAS基因座中的CAD变体相关。 然而，这些基因座中的致病遗传变异仍有待阐明。因此，作为建议的一部分， 研究中，我们将首先进行大规模平行的报告分析，以确定调节基因的变异， SMC中的表达。我们还将利用基因表达的自然变异来构建共- 表达和贝叶斯网络，以了解预测的候选因果基因在SMC中的功能。 我们将通过将调节元件映射到新生RNA转录物来完善这些网络，以响应前- 炎性细胞因子然后，我们将验证我们的预测在增益和功能损失的实验， 培养的SMC。我们还将验证我们的预测，在良好的表型冠状动脉标本的情况下， 通过对基因编码的蛋白质进行免疫组织化学分析， 被预测在动脉粥样硬化相关SMC表型中起关键作用。拟议的总体目标 研究的目的是整合系统遗传学和计算生物学，从而对遗传学的机制进行预测。 被CAD干扰的基因网络。除了了解CAD基因座，这些综合遗传学研究 将提供一个有用的窗口，从遗传变异到SMC基因的生物信息流 表达和动脉粥样硬化相关表型。

PROJECT SUMMARY Coronary artery disease (CAD) remains the leading cause of death in the Western world despite significant advances in early detection and extensive use of lipid-lowering and anti-hypertensive drugs. To date, no single drug has been developed to target the primary disease process in the vessel wall. A complete understanding of the disease susceptibility is urgently needed to develop additional therapies. Common forms of atherosclerosis involve environmental factors, hundreds of genetic variations, and their interactions, each of which exert a relatively small effect on disease susceptibility. The most recent genome-wide association study (GWAS) in nearly six hundred fifty thousand individuals identified 175 independent variants associated with increased risk for CAD. However, most of the underlying genes and the related mechanisms of how these variants contribute to the disease process remain unknown. This proposal outlines an integrative genetics study in a unique resource of human aortic smooth muscle cells (SMCs) isolated from 151 genotyped multi- ethnic heart transplant donors to discover the CAD-associated variants that perturb SMC gene expression and their downstream functional consequences. In recent studies, we measured gene expression in quiescent and proliferative culture conditions representing the transdifferentiation of SMCs from a healthy to an atherogenic phenotype. We identified 84 genes whose expression was associated with CAD variants in GWAS loci. However, the causal genetic variants in these loci remain to be elucidated. Therefore, as part of the proposed studies, we will first perform massively parallel reporter assays to identify the variants that modulate gene expression in SMCs. We will also take advantage of the natural variation in gene expression to construct co- expression and Bayesian networks to understand how the predicted candidate causal genes function in SMCs. We will refine these networks by mapping regulatory elements to nascent RNA transcripts in response to pro- inflammatory cytokines. We will then validate our predictions in gain and loss-of-function experiments in cultured SMCs. We will also validate our predictions in well-phenotyped coronary artery specimens from cases of unexpected sudden death by performing immunohistochemical analysis of proteins encoded by genes that are predicted to play a key role in atherosclerosis-relevant SMC phenotypes. The overall goal of the proposed studies is to integrate systems genetics and computational biology leading to mechanistic predictions of the gene networks that are perturbed by CAD. Besides understanding CAD loci, these integrative genetics studies will provide a useful window into the flow of biological information from genetic variants to SMC gene expression and atherosclerosis-relevant phenotypes.