SIGNALING MOLECULES IN ACUTE LUNG INJURY

急性肺损伤中的信号分子

• 批准号: 6272944
• 负责人: Guy A. Zimmerman
• 金额: $ 15.89万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-12-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6272944
• 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.

炎症机制参与了炎症的启动、放大、 成人呼吸窘迫综合征的传播与解决 (ARDS)。中性粒细胞在ARDS患者的肺部积聚， 释放颗粒酶和其他毒素，介导对细胞的损害 在体外对肺泡毛细血管膜有损伤作用，对肺组织有损伤作用。 活体实验动物。类似的信号分子，如 直接激活中性粒细胞的白介素类和生物活性脂类 并诱导颗粒物的动员，氧气的产生 自由基和其他功能改变通过内皮表达 和ARDS中的其他细胞。其中许多信号的身份 分子仍然是未知的，以及产生这些分子的机制 以一种不受管制的、有害的方式表达，与 一种动态平衡、保护性的时尚仍未被定义。这一目标的总体目标 项目是表征不同类型的中性粒细胞信号分子 类，定义控制其表达的机制，以及 确定失调的机制。我们在这里将重点放在 一种诱导中性粒细胞的信号分子的特性 脱颗粒，因为这一事件似乎特别重要 在ARDS的发病机制中起重要作用。 在初步实验中，我们发现血管内皮细胞经 细胞因子IL-1和TNFa或与内毒素共同合成信号分子 诱导中性粒细胞分泌乳铁蛋白，这是一种特殊的颗粒标志物 弹性蛋白酶，初级颗粒蛋白水解酶，进入液体相。最大 脱颗粒信号的产生与表面分离 介导中性粒细胞黏附和移行的分子的表达。 这些特征表明脱颗粒因子不参与 中性粒细胞生理性迁移。这些功能表明， 脱颗粒因子不参与生理性靶向事件。 此外，内皮细胞单层在孵育时被破坏。 与PMN在脱颗粒活动中的存在，表明 该因子诱导的弹性蛋白酶或其他中性粒细胞蛋白的释放 介导血管内皮损伤。 我们的假设是人类内皮细胞产生并释放一种 刺激中性粒细胞脱颗粒的新型信号分子。PMN颗粒状 蛋白水解酶放大对肺泡毛细血管膜的损伤，并可能 ARDS中血管破坏的关键介质。监管不力 内皮细胞表达信号分子是最基本的 急性肺损伤的病理生理机制。 我们的具体目标是：1)纯化、鉴定、测序和克隆 新的脱粒因子。2)确定生物活动的特征 脱粒因子的作用。3)对合成产物进行表征 该因子的分泌并确定其与其他信号的关系 分子。4)确定脱粒因子是否在 急性期、亚急性期和非急性期患者的血液或肺组织 ARDS的恢复期。