Inhibition of platelet-leukocyte interactions to treat TRALI

描述(由申请人提供)：本申请涉及广泛的挑战领域(04)临床研究，特殊挑战主题04-HL-103评估白细胞与血小板、红细胞和内皮细胞相互作用在心肺和血液疾病发病机制中的作用。 输血相关急性肺损伤(TRALI)是FDA报告的与输血相关的发病率和死亡率的主要原因，是一种在输血后6小时内发生急性肺损伤的临床综合征。尽管其病理生理机制尚不清楚，但抗体和/或激活中性粒细胞(PMN)的生物活性脂质已被认为是具有易感性促炎事件的患者的始发症状。我们的初步研究表明，血小板-白细胞的相互作用在该病中起着关键作用。更具体地说，E-选择素与中性粒细胞上表达的E-选择素配体-1(ESL-1)结合产生的内皮信号，诱导了爬行PMN前沿的整合素Mac-1的激活，从而允许捕获血小板，进而通过产生活性氧(ROS)而导致损伤。目前的挑战是进行临床前研究，并开发新的方法来检测这种延迟的PMN激活。拟议的翻译研究将导致一项临床试验，测试新型拮抗剂对TRALI中涉及的黏附分子的安全性和有效性。在具体目标1中，我们评估了新型选择素拮抗剂GMI-1070在已建立的TRALI小鼠模型中的疗效。在具体目标2中，我们将建立一种人源化的TRALI模型，在该模型中，通过移植脐带血来源的造血干细胞和免疫缺陷的NOD/SCID小鼠的祖细胞来携带循环中的人PMN，这些NOD/SCID小鼠缺乏IL-2R共同的伽马链。我们将通过注射抗HNA-2a来诱导TRALI，这之前被证明在体外大鼠模型中产生肺损伤。我们将使用多通道荧光活体显微镜(MFIM)来评估注射这种抗体是否会诱导血小板-白细胞相互作用和ROS的产生。我们将通过MFIM检测GMI-1070对肺损伤和血小板-白细胞相互作用的影响。在具体目标3中，我们将利用血小板与中性粒细胞极化前沿的复合体的血流成像，开发一种临床上相关的中性粒细胞激活第二波的生物标志物。本实验将提供一个新的生物学终点来评估临床试验中PMN的激活和抗炎药物的疗效。 公共卫生相关性：初步研究表明，血小板-白细胞相互作用在TRALI的发病机制中起关键作用。在这项提案中，我们将进行转化性研究，并开发新的工具来准备治疗和/或预防TRALI的临床试验。

DESCRIPTION (provided by applicant): This application addresses broad Challenge Area (04) Clinical Research, and the specific Challenge Topic 04-HL-103 Assess the role of leukocyte interaction with platelets, erythrocytes, and endothelium in the pathogenesis of heart, lung, and blood diseases. Transfusion-related acute lung injury (TRALI), the main cause of transfusion-related morbidity and mortality reported to the FDA, is a clinical syndrome in which acute lung injury occurs within 6 hours of a blood transfusion. Although its pathophysiology remains unclear, antibodies and/or bioactive lipids activating polymorphonuclear neutrophils (PMNs) have been suggested to initiate the syndrome in patients with a predisposing pro-inflammatory event. Our preliminary studies suggest that platelet-leukocyte interactions play a key role in the disease. More specifically, endothelial signals emerging from the engagement of E- selectin with E-selectin ligand-1 (ESL-1) expressed on PMNs, induced the activation of the integrin Mac-1 at the leading edge of crawling PMNs, allowing the capture of platelets which, in turn, led to injury through the production of reactive oxygen species (ROS). The present challenge is to conduct pre-clinical studies and develop novel methods to assay this type of delayed PMN activation. The proposed translational studies will lead to a clinical trial testing the safety and efficacy of novel antagonists against adhesion molecules involved in TRALI. In Specific Aim 1, we evaluate the efficacy of GMI-1070, novel selectin antagonist, in an established mouse model of TRALI. In Specific Aim 2, we will develop a humanized model of TRALI in which mice harbor circulating human PMNs by transplantation of cord blood-derived hematopoietic stem and progenitor cells in immunodeficient NOD/SCID mice deficient in the IL-2r common gamma chain. We will induce TRALI by injection of an anti-HNA-2a, which was previously shown to produce lung injury in a rat ex vivo model. We will evaluate using multichannel fluorescence intravital microcopy (MFIM) whether the administration of this antibody induces platelet-leukocyte interactions and ROS generation. We will determine the effect of GMI-1070 administration on lung injury, and platelet-leukocyte interactions by MFIM. In Specific Aim 3, we will develop a clinically relevant biological marker of the secondary wave of PMN activation using flow-based imaging of platelet complexes with the polarized leading edge of PMNs. This assay will provide a novel biological end-point to assess PMN activation and the efficacy of anti-inflammatory drugs in clinical trials. PUBLIC HEALTH RELEVANCE: Preliminary studies suggest that platelet-leukocyte interactions play a key role in the pathogenesis of TRALI. In this proposal, we will perform translational studies and develop new tools in preparation of a clinical trial to treat and/or prevent TRALI.