Mechanisms of PMN-mediated Lung Inflammation and Injury

PMN 介导的肺部炎症和损伤的机制

• 批准号: 7457947
• 负责人: Asrar B. Malik
• 金额: $ 32.04万
• 依托单位: UNIVERSITY OF ILLINOIS AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-08-01 至 2010-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7457947
• 关键词: 4-ethoxymethylene-2-phenyl-2-oxazoline-5-one; Acute; Adaptor Signaling Protein; Address; Adhesions; Cell Adhesion Molecules; Cell surface; Coupled; Edema; Endothelial Cells; Event; Genetic; Inflammatory; Injury; Intercellular adhesion molecule 1; Lung; Lung Inflammation; Mediating; Microvascular Permeability; Molecular; Mus; NADPH Oxidase; NF-kappa B; Oxidants; Pathway interactions; Phosphotransferases; Physiological; Positioning Attribute; Protein Biosynthesis; Role; Signal Pathway; Signal Transduction; Therapeutic; cytokine; early onset; migration; neutrophil; p21 activated kinase; research study; tumor necrosis factor alpha receptor

The overall objective of Project 1 is to address the critical signaling pathways by which the pro-inflammatory cytokine TNFalpha mediates the expression of the adhesion molecule, ICAM-1, in endothelial cells and thereby induces firm neutrophil (PMN) adhesion. As stable and firm ICAM-1-dependent adhesion of PMNs to endothelial cells may require rapid-onset, protein synthesis-independent ICAM-1 expression as well as delayed protein synthesis-dependent ICAM-1 expression, we will explore both the early course of its expression involving cell surface alterations in the constitutively expressed ICAM-1 in endothelial cells and the delayed expression requiring de novo protein synthesis. We will determine 1) the role of intracellular oxidant signaling by the gp91(phox) (Nox2) NADPH oxidase subunit vs. Nox4 in endothelial cells in mediating ICAM-1 expression and PMN adhesion to endothelial cells downstream of activation of specific TNFalpha receptors, 2) the central role of PKCzeta and its adaptor protein p62 in activating oxidant signaling and thereby in signaling NF-kappaB activation and ICAM-1 expression, 3) the role of the kinases, phosphoinositol 3-kinase and Akt, in signaling PKCzeta activation and thereby in inducing NF-kappaB activation and ICAM-1 expression, and 4) the role of the RhoGTPases, RhoA, Rac, and Cdc42, and downstream effector p21-activated kinase, PAK, in oxidant signaling and mediating the early-onset protein synthesis-independent component of ICAM-1 expression and PMN adhesion. Studies in endothelial cells will utilize molecular approaches to dissect the components of the signaling pathways and delineate the specific pathways mediating ICAM-1 expression, and promoting endothelial adhesivity to PMNs. These studies will be coupled to experiments in intact mouse lung in which the role of these signaling pathways will be determined in mice with specific genetic deletions. The lung studies will involve making physiological assessments of PMN sequestration and migration as well as of microvascular permeability and edema formation. With the completion of these studies, we will have a detailed understanding of the specific signaling mechanisms by which TNFalpha induces endothelial cell ICAM-1 expression and mediates inappropriate PMN adhesion and migration across the pulmonary microvessel barrier. Thus, we will be in the position to develop therapeutic strategies to block the identified specific signaling events mediating acute lung inflammatory injury.

项目 1 的总体目标是解决促炎细胞因子 TNFα 介导内皮细胞中粘附分子 ICAM-1 表达的关键信号通路，从而诱导中性粒细胞 (PMN) 牢固粘附。由于 PMN 与内皮细胞的稳定且牢固的 ICAM-1 依赖性粘附可能需要快速起效、不依赖于蛋白质合成的 ICAM-1 表达以及延迟的蛋白质合成依赖性 ICAM-1 表达，因此我们将探索早期过程。其表达涉及内皮细胞中组成型表达的 ICAM-1 的细胞表面改变以及需要从头合成蛋白质的延迟表达。我们将确定 1) 内皮细胞中 gp91(phox) (Nox2) NADPH 氧化酶亚基与 Nox4 的细胞内氧化信号传导在介导特定 TNFα 受体激活下游的 ICAM-1 表达和 PMN 与内皮细胞的粘附中的作用，2 ) PKCzeta 及其接头蛋白 p62 在激活氧化信号转导进而在信号传导 NF-kappaB 激活中的核心作用和ICAM-1 表达，3) 激酶、磷酸肌醇 3-激酶和 Akt 在信号 PKCzeta 激活中的作用，从而诱导 NF-kappaB 激活和 ICAM-1 表达，以及 4) RhoGTPase、RhoA、Rac 的作用和 Cdc42 以及下游效应器 p21 激活激酶 PAK 在氧化信号传导和介导早发性蛋白质合成独立性中的作用ICAM-1 表达和 PMN 粘附的组成部分。内皮细胞研究将利用分子方法剖析信号通路的组成部分并描绘 介导 ICAM-1 表达并促进内皮细胞与 PMN 粘附的特定途径。这些研究将与完整小鼠肺中的实验相结合，其中这些信号通路的作用将在具有特定基因缺失的小鼠中确定。肺部研究将涉及对中性粒细胞隔离和迁移以及微血管通透性和水肿形成进行生理评估。随着这些研究的完成，我们将详细了解 TNFα 诱导内皮细胞 ICAM-1 表达并介导不适当的 PMN 粘附和跨肺微血管屏障迁移的具体信号机制。因此，我们将能够制定治疗策略来阻断已确定的介导急性肺部炎症损伤的特定信号事件。