Targeted deep sequencing of the <i>PEAR1</i> locus for platelet aggregation in European and African American families
收藏资源简介：
Coronary artery disease (CAD) remains a major cause of mortality and morbidity worldwide. The aggregation of activated platelets on a ruptured atherosclerotic plaque is a critical step in most acute cardiovascular events like myocardial infarction. Platelet aggregation both at baseline and after aspirin is highly heritable. Genome-wide association studies (GWAS) have identified a common variant within the first intron of the platelet endothelial aggregation receptor1 (<i>PEAR1</i>), to be robustly associated with platelet aggregation. In this study, we used targeted deep sequencing to fine-map the prior GWAS peak and identify additional rare variants of <i>PEAR1</i> that account for missing heritability in platelet aggregation within the GeneSTAR families. In this study, 1709 subjects (1043 European Americans, EA and 666 African Americans, AA) from families in the GeneSTAR study were included. In vitro platelet aggregation in response to collagen, ADP and epinephrine was measured at baseline and 14 days after aspirin therapy (81 mg/day). Targeted deep sequencing of <i>PEAR1</i> in addition to 2kb of upstream and downstream of the gene was performed. Under an additive genetic model, the association of single variants of <i>PEAR1</i> with platelet aggregation phenotypes were examined. Additionally, we examined the association between the burden of <i>PEAR1</i> rare non-synonymous variants and platelet aggregation phenotypes. Of 532 variants identified through sequencing, the intron 1 variant, rs12041331, was significantly associated with all platelet aggregation phenotypes at baseline and after platelet inhibition with aspirin therapy. rs12566888, which is in linkage disequilibrium with rs12041331, was associated with platelet aggregation phenotypes but to a lesser extent. In the EA families, the burden of <i>PEAR1</i> missense variants was associated with platelet aggregation after aspirin therapy when the platelets were stimulated with epinephrine (p = 0.0009) and collagen (p = 0.03). In AAs, the burden of <i>PEAR1</i> missense variants was associated, to a lesser degree, with platelet aggregation in response to epinephrine (p = 0.02) and ADP (p = 0.04). Our study confirmed that the GWAS-identified variant, rs12041331, is the strongest variant associated with platelet aggregation both at baseline and after aspirin therapy in our GeneSTAR families in both races. We identified additional association of rare missense variants in <i>PEAR1</i> with platelet aggregation following aspirin therapy. However, we observed a racial difference in the contribution of these rare variants to the platelet aggregation, most likely due to higher residual missing heritability of platelet aggregation after accounting for rs12041331 in the EAs compared to AAs.
冠状动脉粥样硬化性心脏病（Coronary artery disease, CAD）仍是全球范围内导致死亡与致残的主要病因。破裂的动脉粥样硬化斑块表面活化血小板聚集，是绝大多数急性心血管事件（如心肌梗死）发生的关键环节。基线状态及阿司匹林给药后的血小板聚集均具有较高的遗传力。全基因组关联研究（Genome-wide association studies, GWAS）已证实，血小板内皮聚集受体1（platelet endothelial aggregation receptor1, PEAR1）第一内含子区域内的常见变异，与血小板聚集存在稳健的关联。本研究采用靶向深度测序技术，对此前GWAS定位的区域进行精细定位，并在GeneSTAR研究家系中，鉴定出可解释血小板聚集缺失遗传力的PEAR1额外罕见变异。本研究共纳入GeneSTAR研究家系中的1709名受试者，其中1043名为欧洲裔美国人（EA），666名为非裔美国人（AA）。研究人员检测了受试者在基线状态及接受81mg/日阿司匹林治疗14天后，体外血小板对胶原、二磷酸腺苷（ADP）及肾上腺素刺激的聚集反应。对PEAR1基因及其上下游各2kb区域开展了靶向深度测序。基于加性遗传模型，本研究分析了PEAR1单变异与血小板聚集表型之间的关联。此外，本研究还考察了PEAR1罕见非同义变异的携带负荷与血小板聚集表型的相关性。在测序鉴定出的532个变异中，内含子1区域的rs12041331变异，在基线状态及阿司匹林抗血小板治疗后，均与所有血小板聚集表型显著相关。与rs12041331存在连锁不平衡的rs12566888变异，同样与血小板聚集表型相关，但关联强度较弱。在欧洲裔美国人（EA）家系中，当血小板分别经肾上腺素（p=0.0009）及胶原（p=0.03）刺激后，PEAR1错义变异的携带负荷与阿司匹林治疗后的血小板聚集显著相关。在非裔美国人（AA）家系中，PEAR1错义变异的携带负荷仅在较弱程度上与血小板对肾上腺素（p=0.02）及ADP（p=0.04）刺激的聚集反应相关。本研究证实，在本研究的GeneSTAR家系中，无论受试者种族如何，GWAS鉴定出的rs12041331变异均为与基线状态及阿司匹林给药后血小板聚集关联最强的遗传变异。本研究还发现，PEAR1罕见错义变异与阿司匹林治疗后的血小板聚集存在额外关联。但研究观察到，这些罕见变异对血小板聚集的贡献存在种族差异，这大概率是因为，与非裔美国人（AA）家系相比，欧洲裔美国人（EA）家系在计入rs12041331变异后，血小板聚集的剩余缺失遗传力仍更高。
