Identification and study of the vascular disease gene at 9p21.3

描述（由申请人提供）：动脉粥样硬化性冠心病（CHD）的风险有一半是遗传性的，最近有前所未有的大量资源用于采用高密度全基因组扫描的基于关联的研究，以确定与CHD相关的遗传变异。这些研究已经确定了基因组的一个单一区域与9号染色体p21.3的基因间片段中的疾病最高度相关，即染色体9p21.3 CHD相关区域（C9 CAR）。由该基因座变异解释的CHD归因风险估计为10- 15%。除了CHD之外，C9 CAR的变体还与其他血管疾病相关，包括腹主动脉瘤、中风和外周血管疾病。尽管该实验室和其他实验室正在进行更多的人类遗传学绘图工作，但他们不太可能确定致病变异或阐明与9p21.3变异相关的潜在风险的生物学。进一步的进展将需要基础分子生物学和动物模型方法的努力。虽然在9p21.3的这个区域中有几个基因，但没有一个与疾病相关的变异明确相关，并且致病变异尚未确定。最近令人信服的证据表明，细胞周期蛋白依赖性激酶抑制剂基因CDKN 2B和CDKN 2B基因座中的非编码反义RNA ANRIL是最有可能与9p21.3变异相关的候选基因。 本文提出的研究将确定这两个候选基因中的哪一个是相关基因，9p21.3变异改变该基因功能的机制，以及它反过来调控的基本疾病相关途径。特定目标1中的实验将研究CDKN 2B和ANRIL等位基因之间的等位基因表达不平衡，并将这种不平衡与这些基因以及基因间C9 CAR区域的变异联系起来。这些研究将确定致病基因和定位顺式作用的转录调控序列。在这一目标的其他实验将在C9 CAR推定的增强子元件的特点，确定结合这些元素的转录因子，并提供深入了解细胞类型和信号通路，介导与该地区相关的风险。Specific Aim 2将在apoE无效动脉粥样硬化小鼠模型中采用CDKN 2B和9p21.3处的其他基因的靶向缺失，以提供对疾病风险的细胞和分子方面的见解。最后，在特定目标3中，靶向体外研究将进一步研究CDKN 2B或ANRIL如何调节血管细胞类型中的基本细胞命运决定并促成动脉粥样硬化疾病。这项工作将确定9p21.3的致病基因，以及疾病相关的上游和下游通路，以进一步研究和治疗靶向。 公共卫生相关性：世界各地的科学家团体付出了巨大的代价和努力，已经确定了与各种心血管疾病遗传风险相关的人类基因组区域。需要进一步的研究来了解所涉及的特定基因，以及它们如何工作以促进疾病过程。这些信息将有助于为这些疾病开发更好的治疗方法。

DESCRIPTION (provided by applicant): As much as half of the risk for atherosclerotic coronary heart disease (CHD) is genetic in nature, and an unprecedented amount of resources have recently been directed at association-based studies employing high density genome-wide scanning to identify genetic variation associated with CHD. These studies have identified a single region of the genome as the most highly associated with disease in an intergenic segment of chromosome 9 at p21.3, the Chromosome 9p21.3 CHD-Associated Region (C9CAR). The attributable risk for CHD explained by variation in this locus has been estimated at 10-15%. In addition to CHD, variants at C9CAR have been associated with other vascular diseases, including abdominal aortic aneurysm, stroke, and peripheral vascular disease. Although additional human genetics mapping efforts are underway in this laboratory and others, it is unlikely that they will identify the causative variation or elucidate the biology underlying the risk associated with 9p21.3 variants. Further progress will require efforts with basic molecular biology and animal model approaches. While there are several genes in this region of 9p21.3, none have been clearly linked to the disease-associated variation, and the causative variation has not been defined. Compelling recent evidence now suggests that a cyclin-dependent kinase inhibitor gene, CDKN2B, and a non-coding antisense RNA in the CDKN2B locus named ANRIL, are the most likely candidate genes linked to the variation at 9p21.3. Studies proposed here will identify which of these two candidates is the related gene, the mechanism by which 9p21.3 variation alters the function of this gene, and the fundamental disease-related pathways that it in turn regulates. Experiments in Specific Aim 1 will investigate allelic expression imbalance between the alleles of CDKN2B and ANRIL, and link this imbalance to variation in these genes as well as the intergenic C9CAR region. These studies will identify the causative gene and localize cis-acting transcriptional regulatory sequences. Additional experiments in this aim will characterize putative enhancer elements at C9CAR, identify the transcription factors that bind these elements and provide insights into cell types and signaling pathways that mediate the risk associated with this region. Specific Aim 2 will employ targeted deletion of CDKN2B and other genes at 9p21.3 in the apoE null atherosclerosis mouse model to provide insights into the cellular and molecular aspects of disease risk. Finally, in Specific Aim 3, targeted in vitro studies will further investigate how CDKN2B or ANRIL regulate basic cell fate decisions in vascular cell types and contribute to atherosclerotic disease. This work will identify the causative gene at 9p21.3, and disease related upstream and downstream pathways for further study and therapeutic targeting. PUBLIC HEALTH RELEVANCE: Significant expense and effort by groups of scientists around the world has led to identification of regions of the human genome that are associated with the genetic risk for various forms of cardiovascular disease. Additional research is required to understand the specific genes involved, and how they work to contribute to the disease process. Such information will allow the development of better therapeutics for these diseases.