Mechanisms of acute lung injury from blood transfusions.

描述（由申请人提供）：输血的主要非感染性风险之一是发生输血相关急性肺损伤（TRALI），这是美国输血相关死亡的头号原因。我们先前已经在TRALI小鼠模型中表明，中性粒细胞和血小板都是产生急性肺内皮损伤、蛋白渗透性和肺水肿所必需的。然而，中性粒细胞和血小板可能相互作用并最终导致肺损伤的机制尚不清楚。在本申请中，我们将在三个科学目标中测试潜在的机制。在目标1中，我们将测试TRALI中嗜血小板聚集体的存在，并通过使用骨髓嵌合体和从MHC I类基因敲除小鼠和Fcg受体敲除小鼠分离的细胞的体外研究来确定引起聚集体的分子机制。我们还将测试血小板的药理学抑制剂以及这些抑制剂可能改善肺损伤的机制。在目标2中，我们将通过使用中性粒细胞蛋白酶和ROS产生功能缺失突变的小鼠来确定中性粒细胞如何导致肺内皮损伤。我们推测，中性粒细胞胞外陷阱（NET）将形成TRALI在血小板依赖的过程中，暴露细胞外组蛋白，导致肺内皮损伤。在目标3中，我们将使用双光子显微镜在活体小鼠肺中的新应用，以成像我们的TRALI小鼠模型中中性粒细胞和血小板募集的时间序列。使用活体显微镜，我们还将确定中性粒细胞和血小板之间的空间关系，在受伤的肺，这是如何影响NET在肺微血管系统的形成。这项研究的结果将阐明TRALI中肺损伤的机制，并通过关注血小板活化和NET形成的作用，有可能确定治疗急性肺损伤的新的药理学方法。

DESCRIPTION (provided by applicant): One of the major non-infectious risks from blood transfusions is the development of transfusion-related acute lung injury (TRALI), which is the number one cause of transfusion-related mortality in the United States. We have previously shown in a mouse model of TRALI that neutrophils and platelets are both required to produce acute lung endothelial injury, protein permeability, and pulmonary edema. However, the mechanisms by which neutrophils and platelets potentially interact and ultimately lead to lung injury are not known. In this application, we will test potential mechanisms in three scientific aims. In Aim 1, we will test for the presence of neutrophil-platelet aggregates in TRALI and determine the molecular mechanisms responsible for the aggregates by using bone marrow chimeras and in vitro studies with cells isolated from MHC Class I-null mice and Fcg receptor knockouts. We will also test pharmacologic inhibitors of platelets and the mechanisms by which these inhibitors may ameliorate lung injury. In Aim 2, we will determine how neutrophils lead to lung endothelial injury by using mice with loss of function mutations in neutrophil proteases and ROS production. We hypothesize that neutrophil extracellular traps (NETs) will be formed in TRALI in a platelet-dependent process that exposes extracellular histones leading to lung endothelial injury. In Aim 3, we will use a new application of two-photon microscopy in the live, mouse lung to image the temporal sequence of neutrophil and platelet recruitment in our mouse model of TRALI. Using intravital microscopy, we will also determine the spatial relationships between neutrophils and platelets in the injured lung and how this influences NET formation in the lung microvasculature. The results from this investigation will elucidate the mechanisms of lung injury in TRALI, and by focusing on the roles of platelet activation and NET formation it may be possible to identify novel pharmacologic approaches to treating acute lung injury.