Molecular mechanisms linking the CXCL12 pathway to atherosclerosis

CXCL12通路与动脉粥样硬化的分子机制

基本信息

批准号：
9229571
负责人：
Daniel James Rader
金额：
$ 70.5万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-02-01 至 2019-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9229571
关键词：
Allelic Imbalance Alternative Splicing Atherosclerosis Biological Biological Assay Biological Markers Biology Blood Vessels CXCL12 gene CXCR4 Receptors CXCR4 gene Cell Line Cells Chemotaxis Clinical Clinical Medicine Clinical Trials Code Conflict (Psychology)Coronary heart disease Custom Data Data Analyses Disease Endothelial Cells Enrollment Epidemiology Etiology European Evaluation Event Frequencies Gene Expression Genes Genetic Genetic Determinism Genetic Markers Genetic Polymorphism Genetic Variation Genome Genomics Genotype Human In Vitro Inflammatory International Investigation Joints Lead Link Lipids Measurement Measures Messenger RNA Meta-Analysis Molecular Mus Mutate Mutation Myocardial Infarction Participant Pathogenesis Pathway interactions Plasma Population Promoter Regions Prospective Studies Proteins Risk Series South Asian Testing Therapeutic Transcript Transcriptional Regulation Transgenic Organisms Translating Uncertainty Untranslated RNA Variant Woman Wound Healing aged base cost effective disorder risk early onset epidemiology study exome exome sequencing experimental study functional status genetic analysis genome editing genome wide association study high risk humanized mouse in vivo induced pluripotent stem cell loss of function macrophage men migration mouse model novel overexpression programs protein function public health relevance rare variant skills therapeutic target transcription activator-like effector nucleases transcriptome sequencing translational study

项目摘要

DESCRIPTION (provided by applicant): Genome-wide association studies (GWAS) have identified common polymorphisms at the CXCL12 locus significantly associated with coronary heart disease (CHD). We have reproduced the association of this locus with CHD risk in multiethnic studies and have identified a novel variant that increases CHD risk, decreases plasma CXCL12 levels and alters expression of CXCL12 gene. We further hypothesized that if CXCL12 is causally involved in the pathogenesis of CHD than genetic variation at its primary receptor CXCR4 may also be associated with CHD. To test our hypothesis, we investigated genetic variation at the CXCR4 locus through meta-analyses of genetic data on common variants involving ~63,000 CHD cases and ~92,000 controls and fine-mapping experiments in ~50,000 CHD cases and ~50,000 controls. First, we were able to identify a common variant at the CXCR4 locus that is strongly associated with CHD risk (P = 4x10-7). Second, preliminary analyses of fine-mapping studies identified: (i) a low frequency variant in the promoter region of CXCR4 that associates with CHD risk at experiment-wide significance levels (OR: 1.13; P-value: 7.1x10-6) and (ii) a naturally occurring rare missense variant in the CXCR4 gene (I57L; OR: 2.16 P = 6x10-3) associated with increased CHD risk. The same analyses also identified a low-frequency missense variant in the CXCL12 gene (R125C; OR: 3.38; P = 0.01) nominally associated with increased CHD risk. Through mechanistic studies, we were able to further demonstrate that endothelial specific deficiency of CXCR4 leads to accelerated atherosclerosis in mice. Capitalizing on these findings, we plan to conduct genetic, biomarker, and mechanistic studies to investigate the underlying biological mechanisms and the directional impact of the CXCL12/CXCR4 pathway on disease risk. Such evidence will help prioritize or deprioritize existing therapeutic programs that are already considering CXCL12 as a potential therapeutic target in CHD. In particular, we will reinforce our ongoing fine-mapping experiments by integrating (i) whole-exome sequencing studies in 10,000 early-onset MI cases (men and women aged � 50 years) and 10,000 controls. We will further conduct (ii) measurements for circulating plasma CXCL12 levels in 12,000 participants (including 5,500 with incident CHD events and 3,000 participants in a high risk CHD group) enrolled in three prospective studies and three clinical trials. We will integrate evidence on plasma CXCL12 levels, genes and CHD risk to help assess "directionality" and utility of plasma CXCL12 as a marker of "causality". We will mechanistically evaluate at the CXCL12 locus the lead coding and non- coding variants associated with CHD risk in human and murine cells and on mouse atherosclerosis and myocardial infarction. We will also mechanistically evaluate CXCR4 genetic variation in human iPS cell derived macrophages and endothelial cells. We will obtain genotype specific human iPS cells through two complimentary approaches: (i) recall of participants based on genotype and (ii) targeted genome editing through TALENs. We will further conduct studies to investigate CXCR4 expression and protein function by genotype through specific quantitative and functional assays. Findings from the proposed study should have considerable translational implications. The two joint-PIs provide internationally recognized cross-disciplinary expertise in vascular biomarkers, epidemiology, experimental biology, and clinical medicine, a combination of skills that will help translate findings for clinical benefit.

描述（由申请人提供）：全基因组关联研究 (GWAS) 已鉴定出 CXCL12 位点的常见多态性与冠心病 (CHD) 显着相关。我们已在多种族研究中重现了该位点与 CHD 风险的关联，并已确定。一种增加 CHD 风险、降低血浆 CXCL12 水平并改变 CXCL12 基因表达的新变异，我们进一步发现 CXCL12 是否与此相关。 CHD 的发病机制比其主要受体 CXCR4 的遗传变异也可能与 CHD 相关。为了检验我们的假设，我们通过对涉及约 63,000 个 CHD 病例和约 92,000 个常见变异的遗传数据进行荟萃分析来研究 CXCR4 位点的遗传变异。首先，我们能够识别 CXCR4 的常见变异。其次，精细定位研究的初步分析发现：(i) CXCR4 启动子区域的低频变异与实验范围内的 CHD 风险相关。水平（OR：1.13；P 值：7.1x10-6）和 (ii) CXCR4 基因中天然存在的罕见错义变异（I57L；OR：2.16 P = 6x10-3）与 CHD 风险增加相关。通过机制研究，我们还发现 CXCL12 基因中的低频错义变异（R125C；OR：3.38；P = 0.01）与 CHD 风险增加相关。能够进一步证明 CXCR4 的内皮特异性缺陷会导致小鼠动脉粥样硬化加速，利用这些发现，我们计划进行遗传、生物标志物和研究。旨在调查 CXCL12/CXCR4 通路对疾病风险的潜在生物学机制和定向影响的机制研究将有助于优先考虑或取消优先考虑已将 CXCL12 作为 CHD 潜在治疗靶点的现有治疗方案。通过整合 (i) 对 10,000 例早发 MI 病例（年龄≤ 50 岁的男性和女性）的全外显子组测序研究，加强我们正在进行的精细绘图实验我们将进一步对参与三项前瞻性研究和三项临床试验的 12,000 名参与者（包括 5,500 名发生 CHD 事件的参与者和 3,000 名高风险 CHD 组的参与者）进行循环血浆 CXCL12 水平的测量。血浆 CXCL12 水平、基因和 CHD 风险，以帮助评估血浆 CXCL12 作为“因果关系”标记的“方向性”和效用。我们还将机械地评估人类 iPS 细胞衍生的巨噬细胞和内皮细胞中的 CXCR4 遗传变异。我们还将通过两种互补的方法获得基因型特异性人类 iPS 细胞。 (i) 根据基因型召回参与者，以及 (ii) 通过以下方式进行有针对性的基因组编辑我们将通过特定的定量和功能测定进一步对 CXCR4 表达和蛋白质功能进行研究，这两个联合 PI 提供了国际公认的血管生物标志物、流行病学方面的跨学科专业知识。、实验生物学和临床医学，这些技能的结合将有助于将研究成果转化为临床效益。