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。血小板是血栓形成的主要成分，但AMI之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性疾病见解。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。从巨核细胞的细胞质延伸产生，血小板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，血小板转录谱提供了一个新的窗口基因表达前急性冠状动脉事件。我们分析了急性ST段抬高性心肌梗死（STEMI）或稳定性冠状动脉疾病（CAD）患者的血小板mRNA。从STEMI和CAD患者分离的血小板含有54个差异表达的转录本。微阵列中STEMI的最强鉴别因子之一是骨髓相关蛋白-14（MRP-14）（P=0.002）。MRP-14是调节钙信号传导、细胞骨架重组和白细胞运输的Ca 2+调节蛋白的S100家族的成员。STEMI患者血浆MRP-8/14异源二聚体水平明显高于对照组（P<0.001）。在一项针对表面健康女性的前瞻性巢式病例对照研究中，首次心血管（CV）事件的风险随着MRP-8/14的每一个四分位数的增加而增加，因此具有最高水平的女性发生任何CV事件的风险增加4倍（P<0.001）。风险独立于标准风险因素和CRP。此外，初步数据表明，MRP-8/14蛋白存在于血小板中，MRP-14的缺乏减少了血小板介导的血栓形成。这些发现是这个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，并且MRP-8/14的血浆水平用作CV事件的有用预测因子。本提案的总体目标是确定MRP-14在CV疾病中的作用。我们的具体目标是：（1）在体外研究MRP-14是否调节血小板和白细胞功能：（2）用野生型和MRP-14缺陷型小鼠研究MRP-14在血管损伤和血栓形成中的作用;和（3）为了确定MRP-8/14是否可以预测急性冠状动脉综合征患者复发CV事件的风险，来自PROVE IT-TIMI-22的巢式病例对照研究。本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至关重要的作用，因此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.