Genetics and Gene Expression Profiling in Asthma

描述（由申请人提供）：哮喘是最常见的慢性呼吸性肺病，在美国影响超过1700万人;其分子决定因素的鉴定仍然是转化科学的重要优先事项。四年前，我们提出了一个整合的基因组方法，结合全基因组遗传和表达研究（所谓的表达数量性状基因座（eQTL）定位），以促进识别新的调节基因变异有助于哮喘的发病机制和自然史。使用这种方法，我们在四个不同的基因组区域鉴定了赋予哮喘易感性的新型调节遗传变异：染色体17 q位点（包括基因ZPBP 2，GSDMB和ORMDL 3）;脂肪酸去饱和酶位点（FADS 1和FADS 2）; N-乙酰氨基半乳糖苷酶（那牙）位点和因子XIII A亚基（F13 A1）位点。我们现在建议扩展这些研究，目标是（1）绘制有助于哮喘发病机制的其他调节变体;（2）识别与哮喘遗传相关的特定功能调节变体;（3）描述这些候选基因在哮喘发展中的功能作用。在具体目标1中，我们将扩展我们以前在整合基因组学方面的工作，使用来自4个大型现有数据集的4,000多个不同祖先的受试者的数据进行首次eQTL荟萃分析。这项工作的结果将用于重新解释哮喘全基因组关联研究的荟萃分析。将在另外三个哮喘队列（n E12，000）中重复相关性。在特定目标2中，我们将通过等位基因不平衡筛选、基于染色质的DNA-DNA和DNA-蛋白质相互作用研究以及等位基因特异性报告基因测定，对人支气管上皮细胞和相关细胞类型中的三个新型哮喘基因座（FADS 2、那牙和F13 A1）进行功能性精细定位。将在EVE Consortium队列中检测确认的功能变体与哮喘的遗传相关性。在特定目标3中，我们将在已建立的小鼠模型中对FADS 2基因进行功能评价，并在小鼠和人源性人支气管上皮细胞中使用体外细胞试验确认分子机制。该项目具有很高的潜力，可以精确定位有助于哮喘发病机制的功能性遗传变异，并更好地了解这些基因在哮喘发病机制中的作用，从而为旨在改变其异常基因表达的新药开发奠定坚实的基础。 公共卫生相关性：哮喘是最常见的慢性呼吸性肺病，其分子决定因素的识别仍然是转化科学的重要优先事项。通过本申请鉴定的哮喘相关调节基因变异将为哮喘的发病机制提供新的见解。FADS 2的研究将证实其作为治疗开发或通过饮食改变脂肪酸摄入来改善环境的潜在靶点。

DESCRIPTION (provided by applicant): Asthma is the most common chronic respiratory lung disease, affecting more than 17 million people in the US; identification of its molecular determinants remains an important priority in translational science. Four years ago, we proposed an integrative genomic approach that combined genome-wide genetic and expression studies (so-called expression quantitative trait locus (eQTL) mapping) to facilitate the identification of novel regulatory genetic variation contributing to the pathogenesis and natural history of asthma. Using this approach, we identified novel regulatory genetic variants that confer susceptibility to asthma at four distinct genomic regions: the chromosome 17q locus (that includes the genes ZPBP2, GSDMB and ORMDL3); the Fatty Acid Desaturase locus (FADS1 & FADS2); the N-acetyl galactosaminidase (NAGA) locus, and the factor XIII A subunit (F13A1) locus. We now propose to extend these studies with the goals of (1) mapping additional regulatory variants that contribute to the pathogenesis of asthma; (2) identifying the specific functional regulatory variants underlying the genetic associations with asthma; and (3) characterizing the functional role of these candidate genes in the development of asthma. In Specific Aim 1 we will extend our previous work in the integrative genomics by performing a first of its kind eQTL meta-analysis using data from four large existing datasets of more than 4,000 subjects of diverse ancestry. Results from this effort will be used to reinterpret a meta-analysis of asthma genome-wide association studies. Associations will be replicated in three additional asthma cohorts (n E12,000). In Specific Aim 2, we will perform functional fine-mapping of three of the novel asthma loci (FADS2, NAGA and F13A1) in human bronchial epithelial cells and related cell types by means of allelic imbalance screens, chromatin-based DNA-DNA and DNA-protein interaction studies, and allele specific reporter assays. Confirmed functional variants will be tested for genetic association with asthma in the EVE Consortium cohorts. In Specific Aim 3, we will conduct a functional evaluation of the FADS2 gene in an established murine model, with confirmation of the molecular mechanisms using in vitro cellular assays in both murine- and human-derived human bronchial epithelial cells. This project has high potential to precisely localize functional genetic variants contributing to the pathogenesis of asthma, and provide a better understanding of the role of these genes in the pathogenesis of asthma, thereby establishing a solid foundation for new drug development aimed at modifying their aberrant gene expression. PUBLIC HEALTH RELEVANCE: Asthma is the most common chronic respiratory lung disease; identification of its molecular determinants remains an important priority in translational science. The asthma-associated regulatory genetic variants identified through this application will provide novel insights into the pathogenesis of asthma. The studies of FADS2 will confirm it as a potential target for therapeutic development or environmental modification through dietary modification of fatty acid intake.