MRP-14 and Cardiovascular Disease

描述（由申请人提供）：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。血小板是这类血栓的主要组成部分，但AMI发生前的确切分子事件仍不确定。转录谱分析可以产生无偏见的、机制的疾病见解。然而，AMI后的基因表达可能反映了触发事件或斑块破裂和血栓形成的下游后果。血小板由巨核细胞的细胞质延伸产生，保留巨核细胞衍生的mrna。由于血小板是无核的，血小板转录组反映了巨核细胞衍生的mrna。因此，血小板的转录谱分析为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段抬高型心肌梗死（STEMI）或稳定型冠状动脉疾病（CAD）患者的血小板mRNA。从STEMI和CAD患者中分离的血小板含有54个差异表达的转录本。在微阵列中，STEMI的最强鉴别因子之一是髓系相关蛋白-14 (MRP-14) （P=0.002）。MRP-14是Ca2+调节蛋白s100家族的一员，可调节钙信号、细胞骨架重组和白细胞运输。STEMI患者血浆MRP-8/14异源二聚体水平较高（P<0.001）。在一项前瞻性、嵌套病例对照研究中，在表面健康的女性中，MRP-8/14每增加四分位数，首次心血管事件的风险就会增加，因此，mrp水平最高的女性发生任何心血管事件的风险增加了4倍（P<0.001）。危险与标准危险因素和CRP无关。此外，初步数据表明，MRP-8/14蛋白存在于血小板中，MRP-14缺乏可减少血小板介导的血栓形成。这些发现是本修订的翻译应用的基础。该建议的中心假设是MRP-14调节血管损伤和血栓形成中的血小板和白细胞功能，血浆MRP-8/14水平可作为心血管事件的有用预测因子。该提案的总体目标是确定MRP-14在心血管疾病中的作用。我们的具体目的是：(1)研究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缺陷小鼠研究MRP-14在血管损伤和血栓形成中的作用；(3)通过一项来自PROVE IT-TIMI-22的前瞻性巢式病例对照研究，确定MRP-8/14是否能预测急性冠状动脉综合征患者心血管事件复发的风险。本提案中概述的实验应阐明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.