Functional Dissection of the Sudden Cardiac Death Associated BAZ2B locus

描述(由申请人提供)： 尽管最近在治疗和预防冠心病方面取得了进展，但心脏性猝死(SCD)仍然是一个主要的公共卫生问题，在美国每年的发病率为18万-25万。绝大多数SCD事件发生在普通人群中，高达50%的人将SCD作为疾病的首发症状。国家心脏、肺和血液研究所最近的一份共识文件强调了基因贡献对有效预测和预防SCD的关键重要性。我们最近发现了基因组的一个区域，命名为SCD1，包含三个基因，BAZ2B，WDSUB1和TANC1，与SCD的风险密切相关(P=2.2x10-11)。风险等位基因虽然相对罕见(~3%的欧洲血统个体是携带者)，但有很大的影响，使SCD的风险增加2.03倍(95%可信区间1.65-2.49)。我们假设SCD1区域中的一个或多个基因对心血管发育和功能有贡献，并且其中的编码或非编码变异在SCD风险中起重要作用。首先，我们将使用小鼠和斑马鱼模型生物来评估这3个基因中的每一个的生物学相关性。我们将通过整体RNA原位分析和胚胎和出生后心脏切片，确定转录本在小鼠一系列发育和出生后阶段的空间和时间分布。我们将使用斑马鱼来检验这一假说，即在脊椎动物有机体的发育过程中破坏一个或多个候选基因的表达将损害心血管成分的起源和功能。我们预计，这些实验将明确涉及心血管生物学中的一个或多个基因，并进一步为局部基因变异改变人类SCD风险的生物学机制提供初步证据。其次，我们将在3,900个尸检确认的SCD病例和6,000个对照中表征该区域的遗传变异，以：1)识别识别的关联信号背后的功能变异(S)；2)识别与SCD相关的其他变异；3)使用详细的尸检数据分析遗传关联的性质，以确定SCD的原因并对样本进行分层。我们预计，非编码和编码变体都将与SCD相关。对于编码变异，我们将比较含有已识别编码变异的人类RNA与其非变异对应物的能力，以挽救MO诱导的效应。我们将同样分析过度表达的影响。对于非编码变异，我们将首先通过在斑马鱼中转基因来检测选定的相关非编码序列的调控控制。此外，我们将确定已识别的变异是否会改变从尸检心脏获得的RNA的内源性基因表达水平(EQTL)。这项应用弥合了基因关联和功能研究之间的关键差距，利用独特的尸检确定的SCD存储库、高通量下一代测序和模型生物来从功能和基因上剖析GWAs的一个非常重要的发现。

DESCRIPTION (provided by applicant): Despite recent progress in treatment and prevention of coronary heart disease, sudden cardiac death (SCD) remains a major public health problem, with an annual incidence of 180,000-250,000 in the U.S. The vast majority of SCD events occur in the general population, with up to 50% of individuals experiencing SCD as a first sign of disease. The critical importance of genetic contribution for effective prediction and prevention of SCD was emphasized in a recent consensus document from the National Heart Lung and Blood Institute. We have recently identified a region of the genome, designated SCD1, containing three genes, BAZ2B, WDSUB1 and TANC1, that is strongly associated with risk for SCD (P=2.2x10-11). The risk allele, while relatively rare (~3% of individuals of European ancestry are carriers), has a large effect, increasing the risk for SCD by 2.03-fold (95% CI 1.65-2.49). We hypothesize that one or more of the genes in the SCD1 region contribute to cardiovascular development and function and that coding or noncoding variation therein plays an important role in SCD risk. First, we will evaluate the biological relevance of each of the 3 genes using both mouse and zebrafish model organisms. We will determine the spatial and temporal distribution of the transcripts across a range of developmental and post-natal stages in mice through both whole mount RNA in situ analyses and sectioning of embryonic and postnatal heart. We will use zebrafish to test the hypothesis that disruption of the expression of one or more gene candidates during development of vertebrate organism will compromise the genesis and function of cardiovascular components. We anticipate that these experiments will definitively implicate one or more of the genes in cardiovascular biology, and further, provide preliminary evidence for a biological mechanism by which local genetic variation alters the risk for SCD in humans. Second, we will characterize the genetic variation in this region in 3,900 autopsy-identified SCD cases and >6,000 controls to: 1) identify the functional variant(s) underlying the identified association signal; 2) identify additional variants associated with SCD; 3) dissect the nature of the genetic association using detailed autopsy data to define the cause of SCD and stratify samples. We anticipate that both non-coding and coding variants will be associated with SCD. For coding variation, we will compare the capacities of human RNAs containing identified coding variation with their non-variant counterparts to rescue MO-induced effects. We will similarly assay the effects of over-expression. For noncoding variation, we will first assay the regulatory control of selected associated noncoding sequences by transgenesis in zebrafish. Additionally we will determine whether identified variants alter endogenous gene expression levels (eQTL) of RNA obtained from the autopsy hearts. This application bridges a critical gap between genetic association and functional studies, leveraging a unique autopsy-determined SCD repository, high-throughput next generation sequencing, and model organisms to functionally and genetically dissect a highly significant finding from a GWAS.