Systems Genetic Analysis of Atherogenic Transcriptional Regulation in Human Cells

描述（由申请人提供）：动脉粥样硬化是一种复杂的疾病，可导致心脏病发作和中风，具有遗传和环境原因。一个主要的启动因素是血管壁磷脂（OxPLs）的氧化修饰。OxPLs在病变中积累，诱导血管细胞（如内皮细胞）中几种通路的激活，是冠状动脉疾病和死亡的生物标志物。全基因组关联研究（GWAS）正在确定赋予风险的遗传位点。然而，大多数位于大的非蛋白编码区。尽管异常监管可能带来风险，但对监管机制的了解仍然很少。本研究旨在1)确定人类内皮细胞（EC）特性及其对OxPLs的反应的基因组调控元件，2)确定这些调控元件的功能如何受到自然遗传变异的影响。在目标1中，我将检验这样一个假设，即少数决定谱系的转录因子（ldtf）建立了大多数ec特异性增强子，这些增强子赋予对OxPLs的转录应答。基于我最近在巨噬细胞中的发现，这一假设是合理的，这表明相对简单的巨噬细胞组合（ldtf）在建立调控环境中起主导作用。在这些研究中，先前确定的LDTF的特征将用于确定和验证EC LDTF候选者。初步数据表明，ETS、AP-1和FOX转录因子家族成员介导了很大一部分EC调控。在目标1中，我还将确定介导内皮细胞对OxPLs反应的转录因子。假设这些因子在ldtf附近结合。目标1将在该合同的K99阶段完成。在目标2中，我将利用50个基因多样化的初级EC培养物的明确种群来构建数据驱动的监管网络。关联图谱和转录因子基序突变分析将确定干扰调控功能和促动脉粥样硬化表达程序的遗传变异。然后，我将把改变增强子活性的非编码调节变异体与人类疾病联系起来。我

DESCRIPTION (provided by applicant): Atherosclerosis is a complex disease leading to heart attack and stroke that has genetic and environmental causes. A major initiating factor is the oxidative modification of phospholipids (OxPLs) in the vessel wall. OxPLs accumulate in lesions, induce the activation of several pathways in vascular cells such as endothelial cells, and are biomarkers of coronary disease and death. Genome-wide association studies (GWAS) are identifying the genetic loci that confer risk. However, most are located in large non-protein coding regions. Whereas aberrant regulation is likely to confer risk, regulatory mechanisms remain poorly understood. This proposal aims 1) to identify the genomic regulatory elements that specify human endothelial cell (EC) identity and their responses to OxPLs and 2) to define how the functions of these regulatory elements are affected by natural genetic variation. In Aim 1, I will test the hypothesis that a handful of lineage-determining transcription factors (LDTFs) establish the majority of the EC-specific enhancers that confer transcriptional responses to OxPLs. This hypothesis is justified based on my recent findings in macrophages, which demonstrated that relatively simple combinations of macrophage (LDTFs) play dominant roles in establishing the regulatory landscape. Characteristics of LDTFs identified previously will be used to identify and validate EC LDTF candidates in these studies. Preliminary data suggests the members of the ETS, AP-1 and FOX transcription factor families mediate a large proportion of EC regulation. In Aim 1 I will also identify the transcription factors that mediate endothelial responses to OxPLs. These factors are hypothesized to bind in close vicinity to LDTFs. Aim 1 will be completed during the K99 phase of this award. In Aim 2, I will utilize a well-defined population of 50 genetically diverse primary EC cultures to build a data-driven regulatory network. Association mapping and transcription factor motif mutation analysis will identify the genetic variants that perturb regulatory function and pro-atherogenic expression programs. Then, I will relate non-coding regulatory variants that alter enhancer activity to human disease. I hypothesize that these variants are likely to be enriched at GWAS loci for coronary artery disease. In such cases, the functional regulatory variant and cell type mediating susceptibility will be identified. Aim 2 will be completed during the R00 phase. My long-term goal is to elucidate the genetic mechanisms that predispose individuals to develop complex diseases such as atherosclerosis as an independent investigator. In my career, I strive to achieve these goals by integrating the skills acquired during my training as a systems geneticist with my ongoing training in mechanistic gene regulation. I will continue to take advantage of the numerous opportunities in the UCSD research community to enhance my training. My publication record demonstrates the ability to integrate genetics with complex traits using innovative approaches in the mouse and human populations. With support from the diverse group of highly skilled mentors in this application I am optimistic that I will be successful on my pathway to independence.