Functional Genetics of COPD

项目摘要（参见说明）： 该 PPG 的总体目标是了解 COPD 易感性的遗传、基因组和表观遗传决定因素。最近通过全基因组关联研究明确鉴定了三个 COPD 易感基因座——4 号染色体上的两个基因座（HHIP 附近和 FAM13A 中）和 15 号染色体上的一个基因座（包括 IREB2 在内的一组基因）。然而，这些区域的关键遗传决定因素及其对慢性阻塞性肺病的功能影响尚未确定。本 PPG 中的三个项目重点关注遗传学（项目 1，PI：Silverman）；基因表达（项目 2，PI：Choi）；和 DNA 甲基化（项目 3、PI：德梅奥）。这些项目将建立在表型良好的研究人群的现有基础设施、慢性阻塞性肺病表型特征的经验以及慢性阻塞性肺病发病机制的体外和体内功能评估的广泛跟踪记录的基础上。可能还有多个额外的慢性阻塞性肺病易感基因位点需要被发现。其中一些遗传位点可能主要受到表观遗传改变（例如 DNA 甲基化）的影响，而不是受可遗传的 SNP 变异的影响，或者除此之外还受到可遗传的 SNP 变异的影响。此外，与 COPD 的这些遗传决定因素相关的途径的其他基因成员尚不清楚，对基因表达和 DNA 甲基化的评估可能有助于深入了解这些途径。因此，我们将发现其他基因表达和表观遗传对 COPD 易感性的影响作为本 PPG 的中心焦点。此外，GWAS 位点内的实际遗传决定因素尚未得到证实。因此，我们努力将关键基因定位在这些区域内。将使用多种方法来实现这一目标。包括评估不同遗传祖先群体（来自 COPDGene 项目的非裔美国人）的遗传关联、分析 GWAS 位点内基因之间的基因表达、评估 GWAS 位点内基因的表观遗传变化以及远程基因调控分析（例如染色体构象捕获）。除了关键决定因素的定位之外，还需要进行功能验证来确认特定基因参与 COPD 发病机制并了解其影响。我们将采用肺上皮细胞和单核细胞系的体外评估（在原代细胞类型中进行验证）以及关键基因表达不足（敲除）的小鼠模型以及经过长期香烟烟雾暴露测试的易感性与耐药性近交系菌株的体内评估。我们预计这些研究将深入了解 COPD 易感性的途径和机制。

PROJECT SUMMARY (See instructions): The overall goal of this PPG is to understand the genetic, genomic, and epigenetic determinants of variable susceptibility to develop COPD. Three COPD susceptibility loci have recently been definitively identified by genome-wide association studies¿¿¿two loci on chromosome 4 (near HHIP and in FAM13A) and one locus on chromosome 15 (a block of genes including IREB2). However, the key genetic determinants in these regions and their functional impact on COPD have not been defined. The three projects In this PPG focus on Genetics (Project 1, PI: Silverman); Gene Expression (Project 2, PI: Choi); and DNA Methylation (Project 3, PI: DeMeo). These projects will build on a substantial existing infrastructure of well-phenotyped study populations, experience in phenotypic characterization of COPD, and an extensive track record of both in vitro and in vivo functional assessment of COPD pathogenesis. There are likely multiple additional COPD susceptibility loci, which need to be discovered. Some of these genetic loci may be influenced primarily by epigenetic alterations (e.g. DNA methylation) instead of, or In addition to, heritable SNP variation. Moreover, the other gene members of the pathways related to these genetic determinants of COPD are unknown, and assessment of gene expression and DNA methylation can likely provide insight into these pathways. Thus, we have included Discovery of additional gene expression and epigenetic influences on COPD susceptibility as a central focus of this PPG. In addition, the actual genetic determinants within the GWAS loci have not been proven. Thus, we have included efforts to localize the key genes within those regions. Multiple approaches will be used to accomplish this goal. Including assessment of genetic association in a population of different genetic ancestry (African Americans from the COPDGene project), analysis of gene expression among genes within GWAS loci, assessment for epigenetic changes of genes within GWAS loci, and assays of long-range gene regulation (e.g. chromosome conformation capture). In addition to Localization of the key determinants, Functional Validation will be required to confirm that specific genes are Involved in COPD pathogenesis and to understand their impact. We will employ both in vitro assessment within lung epithelial and monocyte cell lines (with validation in primary cell types) as well as in vivo assessment in murine models of underexpression (knockout) of the key genes and susceptible vs. resistant Inbred strains which are tested with long-term cigarette smoke exposure. We anticipate that these studies will provide insight into the pathways and mechanisms for COPD susceptibility.