REGULATION OF NEUTROPHIL-MEDIATED INJURY BY PLATELETS

中性粒细胞被认为是急性炎症的主要细胞介质。 与细菌性心内膜炎，免疫性血管炎， 缺血性心脏病与成人呼吸窘迫综合征 由于它们能够被隔离在脉管系统中， 通过释放有毒的氧气导致内皮细胞的后续损伤 自由基和溶酶体酶 血小板与 这些疾病中的中性粒细胞提示了 炎症 然而，人们对血小板衍生的 调节嗜酸性粒细胞介导的内皮损伤的因子。 我们有 最近描述了血小板衍生蛋白的能力， 调节中性粒细胞炎症的含腺嘌呤核苷酸 功能协调发展的 我们现在寻求支持， 蛋白质抑制剂，并确定蛋白质 抑制剂和腺嘌呤核苷酸调节嗜中性粒细胞介导的损伤， 内皮细胞 拟议研究的目的是测试 血小板衍生因子抑制嗜血小板因子介导的 内皮细胞损伤导致渗透性水肿增加。 的 该项目的具体目标是：1）将 血小板衍生的中性粒细胞抑制因子，并检查 这些抑制剂对体外中性粒细胞功能的影响; 2）确定 这些血小板衍生因子对嗜中性粒细胞介导的损伤的作用， 培养的内皮细胞的功能改变，和3）检查 这些血小板衍生因子抑制 嗜酸性粒细胞介导的内皮细胞损伤。 我们将使用C5 a， F-Met-Leu-Phe（FMLP），诱导细胞快速释放的刺激物， 产品，和佛波醇肉豆蔻酸酯乙酸酯（PMA），诱导更长的 释放产物如活性氧物质。 我们将建立 每种血小板衍生因子的剂量反应和动力学曲线 评估它们对刺激的中性粒细胞功能和 内皮细胞屏障功能。 中性粒细胞调节的机制 通过测量血小板衍生因子， 它们对涉及中性粒细胞活化的不同步骤的影响。 结果 这些研究应提供有用的新信息， 血小板衍生因子对血小板活化的启动和消退的影响 嗜中性粒细胞介导的血管疾病。 这些研究的结果应 也为预防和治疗措施提供了新的可能性 治疗炎症性疾病如ARDS

Neutrophils have been implicated as the major cellular mediator of acute vascular injury associated with bacterial endocarditis, immune vasculitis, ischemic heart disease and the adult respiratory distress syndrome (ARDS) by virtue of their ability to become sequestered in the vasculature and cause subsequent damage to the endothelium by release of toxic oxygen radicals and lysosomal enzymes. The close association of platelets with neutrophils in these disorders suggests potential interactions during inflammation. Yet, little is known about the role of platelet-derived factors in regulating neutrophil-mediated injury to endothelium. We have recently described the ability of platelet-derived proteins as well as adenine-containing nucleotides to regulate neutrophil inflammatory functions. We now seek support to purify and biochemically characterize the protein inhibitor(s) and to determine mechanisms of how the protein inhibitor(s) and adenine nucleotides regulate neutrophil-mediated injury to endothelial cells. The objective of the proposed research is to test the HYPOTHESIS that platelet-derived factors inhibit neutrophil-mediated endothelial cell injury resulting in increased permeability edema. The SPECIFIC AIMS of the project are: 1) to purify to homogeneity the platelet-derived neutrophil inhibitory factors and to examine the effect of these inhibitors on neutrophil functions in vitro; 2) to determine the effect of these platelet-derived factors on neutrophil-mediated injury and functional alterations of cultured endothelial cells, and 3) to examine the cellular mechanisms by which these platelet-derived factors inhibit neutrophil-mediated injury to endothelial cells. We will employ C5a and F-Met-Leu-Phe (FMLP), stimuli that induce rapid release of cellular products, and phorbol myristate acetate (PMA) that induces a more prolonged release of products such as reactive oxygen species. We will establish dose response and kinetic curves for each of the platelet-derived factors to assess their effect on stimulated neutrophil functions and injury of endothelial cell barrier function. The mechanisms of neutrophil regulation by each of the platelet-derived factors will be studied by measurement of their effect on distinct steps involved in neutrophil activation. Results from these studies should provide useful new information on the role of platelet-derived factors on the initiation and resolution of neutrophil-mediated vascular disorders. Results of these studies should also provide new possibilities for prophylactic and therapeutic measures for inflammatory disorders such as ARDS.