Molecular mechanisms linking the CXCL12 pathway to atherosclerosis

CXCL12通路与动脉粥样硬化的分子机制

• 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
• 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

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（通过应用程序提供）：全基因组关联研究（GWAS）已经确定了与冠状动脉疾病（CHD）显着相关的CXCL12基因座的共同多态性。我们已经在多种族研究中重现了该基因座与CHD风险的关联，并确定了一种增加CHD风险，降低血浆CXCL12水平并改变CXCL12基因表达的新型变体。我们进一步假设，如果CXCL12意外地参与了CHD的发病机理，而不是其主要受体CXCR4的遗传变异也可能与CHD有关。为了检验我们的假设，我们通过涉及约63,000个CHD病例和约92,000例对照的常见变体的荟萃分析研究了CXCR4基因座处的遗传变异，并在约50,000个CHD病例和约50,000个对照中进行了〜92,000例对照和细微映射实验。首先，我们能够在CXCR4基因座上识别出与CHD风险密切相关的常见变体（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 风险。相同的分析还确定了CXCL12基因（R125C; OR：3.38; P = 0.01）的低频错义变体，名为与CHD风险的增加相关。通过机械研究，我们能够进一步证明CXCR4的内皮特异性缺乏会导致小鼠的动脉粥样硬化加速。利用这些发现，我们计划进行遗传，生物标志物和机械研究，以研究CXCL12/CXCR4途径对疾病风险的基本生物学机制和指令的影响。这些证据将有助于优先或剥夺现有的治疗计划，这些计划已经将CXCL12视为CHD中潜在的治疗靶标。特别是，我们将通过在10,000例早发的MI病例（50岁）和10,000个对照组中整合（i）（i）（i）（i）（i）（i）（i）全外观测序研究来加强我们正在进行的精细映射实验。我们将进一步进行（ii）对12,000名参与者的循环血浆CXCL12水平进行测量（包括5,500名发生事件冠心病事件，3,000名参与者参加了三项前瞻性研究和三项临床试验。我们将整合有关等离子体CXCL12水平，基因和CHD风险的证据，以帮助评估“方向”和等离子体CXCL12作为“因果关系”的标志。我们将在CXCL12基因座进行机械评估铅编码和非编码变体与人类和鼠细胞中的CHD风险相关，以及小鼠动脉粥样硬化和心肌梗塞。我们还将机械评估人IPS细胞衍生的巨噬细胞和内皮细胞中的CXCR4遗传变异。我们将通过两种免费方法获得基因型特异性人IPS细胞：（i）基于基因型的参与者和（ii）通过TALEN的靶向基因组编辑的参与者。我们将进一步进行研究，以通过特定的定量和功能分析来研究CXCR4表达和蛋白质功能。拟议的研究的发现应考虑转化含义。这两种联合PI提供了国际认可的血管生物标志物，流行病学，实验生物学和临床医学方面的跨学科专业知识，这些技能将有助于转化发现结果以获得临床利益。