SIGNALING MOLECULES IN ACUTE LUNG INJURY

急性肺损伤中的信号分子

• 批准号: 6242250
• 负责人: Guy A. Zimmerman
• 金额: $ 15.46万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-12-01 至 1997-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6242250
• 关键词: adult respiratory distress syndrome; biological signal transduction; chemical structure function; cytokine; gene expression; granule; human subject; inflammation; leukocyte activation /transformation; molecular cloning; neutrophil; protein sequence; protein structure function; secretion; selectins; tissue /cell culture; vascular endothelium

Inflammatory mechanisms are involved in the initiation, amplification, propagation, and resolution of Adult Respiratory Distress Syndrome (ARDS). Neutrophils accumulate in the lungs of patients with ARDS, release granular enzymes and other toxins that mediate damage to cells of the alveolar-capillary membrane in vitro, and injure lungs of experimental animals in vivo. Similarly signaling molecules, such as interleukin and biologically-active lipids, that directly activate PMNs and induced mobilization of granular contents, generation of oxygen radicals, and other functional alterations are expressed by endothelium and other cells in ARDS. The identities of many of these signaling molecules remain unknown, and the mechanisms that cause such molecules to become expressed in a dysregulated, injurious fashion, as opposed to a homeostatic, protective fashion, remain undefined. Broad goals of this project are to characterize neutrophil signaling molecules of different classes, define the mechanisms that regulate their expression, and determine mechanisms of dysregulation. We will focus here on characterization of a signaling molecule that induces neutrophil degranulation, because this event appears to be of particular importance in the pathogenesis of ARDS. In preliminary experiments, we found that endothelial cells treated with the cytokines IL-1 and TNFa or with LPS, synthesize a signaling molecule that induces PMN to secrete lactoferrin, a specific granule marker, and elastase, primary granule protease, into the fluid phase. Maximal generation of the degranulating signal is dissociated from surface expression of molecules that mediate adhesion and transmigration of PMN. These features suggest that the degranulating factor is not involved in physiologic transmigration of PMN. These features suggest that the degranulating factor is not involved in physiologic targeting events. Furthermore, endothelial cell monolayers are disrupted when incubated with PMN in the presence of the degranulating activity, suggesting that release of elastase or other PMN proteases induced by this factor mediates endothelial injury. Our hypotheses are that human endothelial cells generate and release a novel signaling molecule that stimulates PMN degranulation. PMN granular proteases amplify injury to the alveolar capillary membrane and may be key mediators of vascular destruction that occurs in ARDS. Dysregulated expression of signaling molecules by endothelial cells is a fundamental pathophysiologic mechanism in acute lung injury. Our specific aims are: 1) To purify, characterize, sequence, and clone the new degranulating factor. 2) To characterize the biologic activities of the degranulating factor. 3) To characterize the synthesis and secretion of the factor and define its relationship to other signaling molecules. 4) To determine if the degranulating factor is found in the blood or lung tissue of patients during the acute, subacute, and reparative phases of ARDS.

炎症机制涉及启动、放大、 成人呼吸窘迫综合征的传播和解决 （ARDS）。 中性粒细胞积聚在 ARDS 患者的肺部， 释放颗粒酶和其他毒素，介导细胞损伤 体外的肺泡毛细血管膜，并损伤肺 实验动物体内。 类似的信号分子，例如 白细胞介素和生物活性脂质，直接激活中性粒细胞 并诱导颗粒内容物的动员，产生氧气 自由基和其他功能改变由内皮细胞表达 和 ARDS 中的其他细胞。 许多这些信号的身份 分子仍然未知，并且导致这些分子的机制 以一种失调的、有害的方式表达，而不是 一种稳态的、保护性的时尚，仍然没有定义。 本次活动的总体目标 该项目的目的是表征不同的中性粒细胞信号分子 类，定义调节其表达的机制，以及 确定失调的机制。 我们将在这里重点关注 诱导中性粒细胞的信号分子的表征 脱粒，因为这个事件似乎特别重要 在 ARDS 的发病机制中。 在初步实验中，我们发现经处理的内皮细胞 细胞因子 IL-1 和 TNFa 或与 LPS 一起合成信号分子 诱导 PMN 分泌乳铁蛋白（一种特定的颗粒标记物），以及 弹性蛋白酶，初级颗粒蛋白酶，进入流体相。 最大 脱颗粒信号的产生与表面分离 介导 PMN 粘附和迁移的分子的表达。 这些特征表明脱粒因子不参与 PMN 的生理迁移。 这些特征表明 脱颗粒因子不参与生理靶向事件。 此外，内皮细胞单层在孵育时会被破坏 与 PMN 存在脱粒活性，表明 由该因子诱导的弹性蛋白酶或其他 PMN 蛋白酶的释放 介导内皮损伤。 我们的假设是人类内皮细胞产生并释放 刺激 PMN 脱颗粒的新型信号分子。 颗粒状中性粒细胞 蛋白酶会加剧对肺泡毛细血管膜的损伤，并且可能 ARDS 中发生血管破坏的关键介质。 失调 内皮细胞表达信号分子是一个基本的 急性肺损伤的病理生理机制。 我们的具体目标是： 1) 纯化、表征、测序和克隆 新的脱粒因子。 2）表征生物活性 脱粒因子。 3) 表征合成和 该因子的分泌并定义其与其他信号传导的关系 分子。 4) 确定脱粒因子是否存在于 急性、亚急性和急性期患者的血液或肺组织 ARDS 的修复阶段。