MRP-14 and Cardiovascular Disease

描述(申请人提供)：急性心肌梗死(AMI)通常由动脉粥样硬化斑块破裂和血栓形成引起。血小板是这种血栓的主要成分，然而，在急性心肌梗死之前发生的确切分子事件仍不确定。转录图谱可以产生公正的、机械性的疾病洞察。然而，急性心肌梗死后的基因表达可能反映了斑块破裂和血栓形成的触发事件或下游后果。从巨核细胞的细胞质延伸产生的血小板保留了来自巨核细胞的mRNAs。因为血小板是无核的，所以血小板转录组反映了巨核细胞来源的mRNAs。因此，血小板的转录图谱为研究急性冠状动脉事件前的基因表达提供了一个新的窗口。我们分析了急性ST段抬高心肌梗死(STEMI)或稳定性冠状动脉疾病(CAD)患者的血小板mRNA。从STEMI和CAD患者分离的血小板包含54个差异表达的转录本。在微阵列中，髓系相关蛋白-14(mrp-14)是STEMI的最强鉴别因素之一(P=0.002)。MRP-14是S100-钙调节蛋白家族中的一员，它调节钙信号、细胞骨架重组和白细胞转运。ST段抬高心肌梗死患者血浆MRP-8/14异源二聚体水平较高(P&lt；0.001)。在一项在看似健康的女性中进行的前瞻性嵌套病例对照研究中，MRP-8/14每增加四分位数，首次心血管(CV)事件的风险就会增加，因此水平最高的女性发生任何心血管事件的风险会增加4倍(P&lt；0.001)。风险与标准危险因素和C反应蛋白无关。此外，初步数据表明，MRP-8/14蛋白存在于血小板中，缺乏MRP-14会减少血小板介导的血栓形成。这些发现是修改后的翻译应用程序的基础。这一建议的中心假设是，MRP-14在血管损伤和血栓形成中调节血小板和白细胞的功能，而血浆MRP-8/14水平可作为心血管事件的有用预测指标。该提案的总体目标是确定MRP-14在心血管疾病中的作用。我们的具体目标是：(1)检测MRP-14是否在体外调节血小板和白细胞的功能；(2)利用野生型和MRP-14基因缺陷小鼠研究MRP-14在血管损伤和血栓形成中的作用；以及(3)利用Proven IT-TIMI-22进行的一项前瞻性嵌套病例对照研究，确定MRP-8/14是否可预测患有急性冠状动脉综合征的患者复发心血管事件的风险。该提案中概述的实验应该阐明MRP-14在血管损伤和血栓形成中的作用。由于炎症在动脉粥样硬化中起着关键作用，了解血管炎症的分子和细胞机制将为开发预测和治疗动脉粥样硬化血栓形成事件的新策略提供必要的见解。

DESCRIPTION (provided by applicant): Acute myocardial infarction (AMI) commonly results from atherosclerotic plaque disruption and thrombosis. Platelets constitute a major component of such thrombi, yet the precise molecular events that immediately precede AMI remain uncertain. Transcriptional profiling can yield unbiased, mechanistic disease insights. However, gene expression following AMI may reflect either triggering events or downstream consequences of plaque rupture and thrombosis. Generated from cytoplasmic extensions from megakaryocytes, platelets retain megakaryocyte-derived mRNAs. Since platelets are anuclear, the platelet transcriptome mirrors megakaryocyte-derived mRNAs. Thus, transcriptional profiling of platelets provides a novel window on gene expression preceding acute coronary events. We profiled platelet mRNA from patients with acute ST-segment elevation myocardial infarction (STEMI) or stable coronary artery disease (CAD). Platelets isolated from STEMI and CAD patients contained 54 transcripts that were differentially expressed. One of the strongest discriminators of STEMI in the micorarrays was myeloid-related protein-14 (MRP-14) (P=0.002). MRP-14 is a member of the S100-family of Ca2+modulated proteins that modulate calcium signaling, cytoskeletal reorganization, and leukocyte trafficking. Plasma levels of MRP-8/14 heterodimer were higher in STEMI patients (P<0.001). In a prospective, nested case-control study among apparently healthy women, the risk of a first cardiovascular (CV) event increased with each increasing quartile of MRP-8/14 such that women with the highest levels had a 4-fold increase risk of any CV event (P<0.001). Risks were independent of standard risk factors and CRP. Furthermore, preliminary data indicate that MRP-8/14 protein is present in platelets and deficiency of MRP-14 reduces platelet-mediated thrombosis. These findings are the basis for this revised translational application. The central hypotheses of this proposal are that MRP-14 modulates platelet and leukocyte functions in vascular injury and thrombosis and that plasma level of MRP-8/14 serves as a useful predictor of CV events. The overall objective of this proposal is to define the role of MRP-14 in CV disease. Our specific aims are: (1) To examine whether MRP-14 modulates platelet and leukocyte functions in vitro; (2) To investigate the role of MRP-14 in vascular injury and thrombosis using wild-type and MRP-14-deficient mice; and (3) To determine whether MRP-8/14 predicts the risk of recurrent CV events in patients presenting with acute coronary syndromes using a prospective, nested case-control study from PROVE IT-TIMI-22. The experiments outlined in this proposal should clarify the role of MRP-14 in vascular injury and thrombosis. Because inflammation plays a critical role in atherosclerosis, understanding the molecular and cellular mechanisms of vascular inflammation will provide insights necessary to develop novel strategies for predicting and treating atherothrombotic events.