Functional Genomics of Atrial Fibrillation in Human Atria

描述（由申请人提供）：房颤（AF）增加心力衰竭、中风和死亡的风险，并且发现AF具有显著的遗传成分。全基因组关联研究（GWAS）已经确定了许多与房颤风险增加相关的单核苷酸多态性（snp）。然而，致病变异、相关基因和它们促进房颤的机制仍不清楚。为了加强我们对遗传性房颤致病基因的理解，我们建议评估在最近的GWAS中发现的snp对目标组织（人类左心房）中信使RNA、miRNA和相关蛋白表达的影响，这些目标组织来自心脏手术患者的1000多个人类心房组织的独特生物库。具体目的是：1)确定房颤表型如何改变人类心房转录组；2)鉴定和测试改变心房转录表达的候选功能遗传变异。Aim 1研究将使用最先进的技术（RNA-seq, miRNA-seq）和生物信息学来确定AF表型与基因转录物的关联，包括低表达转录物和mRNA同种异构体、mirna和共调控基因模块。我们将在心房肌细胞细胞系、人类esc来源的心房细胞和人类心房成纤维细胞中使用siRNA敲低和cDNA转染策略来测试调节选定基因的功能影响，以确定这些基因的表达改变是否会影响下游基因表达和选定的生物学途径。目的2研究将通过表达数量性状位点（eQTL）和等位基因表达不平衡分析确定与心房基因表达相关的遗传变异。候选变异将在报告基因转染研究中得到验证。建议的跨学科研究是

DESCRIPTION (provided by applicant): Atrial fibrillation (AF) increases risk of heart failure, stroke and death, and AF has been found to have a significant heritable component. Genome wide association studies (GWAS) have identified numerous single nucleotide polymorphisms (SNPs) associated with increased risk of AF. However, the causative variants, relevant genes and mechanisms by which they promote AF remain unclear. To enhance our understanding of the causative genes involved in heritable AF, we propose to evaluate the impact of SNPs identified in recent GWAS on the expression of messenger RNA, miRNA and related proteins in the target tissue of interest, human left atria, taken from a unique biorepository of over 1000 human atrial tissues from cardiac surgery patients. Specific aims are: 1) To determine how AF phenotypes alter the human atrial transcriptome, and 2) To identify and test candidate functional genetic variants that alter atrial transcript expression. Aim 1 studies will use state-of-the-art technology (RNA-seq, miRNA-seq) and bioinformatics to determine AF phenotype associations with gene transcripts, including lowly expressed transcripts and mRNA isoforms, and miRNAs, and co-regulated gene modules. We will test the functional effects of regulating selected genes using siRNA knockdown and cDNA transfection strategies in an atrial myocyte cell line, human ESC-derived atrial cells and in human atrial fibroblasts to determine whether altered expression of these genes affects downstream gene expression and selected biological pathways. Aim 2 studies will identify genetic variants associated with atrial gene expression by expression quantitative trait locus (eQTL), and allelic expression imbalance analyses. Candidate variants will be validated in reporter gene transfection studies. The proposed interdisciplinary studies are a logical and important follow up to recent GWAS that will provide novel, unbiased mechanistic insights into the impact of SNPs highly associated with AF on atrial RNA expression patterns. We expect our studies to identify functional links between AF-associated genetic loci and gene expression, and to identify SNPs, genes, and pathways that are causally related to the etiology and progression of AF and that may represent new targets for AF treatment and prevention. PUBLIC HEALTH RELEVANCE: Atrial fibrillation (AF), associated with aging, obesity, risk for stroke, heart failure and death, afflicts millions of Americans with an incidence that is projected to triple over the next several decades. AF susceptibility is heritable, but despite successful identification of genetic variants associated with AF, the links between these findings and how they cause AF remain unclear. The proposed studies aim to make these functional connections, which will facilitate identification of new targets for AF treatment and prevention.