NADPH OXIDASE REGULATION OF THE MACROPHAGE INFLAMMATORY PHENOTYPE IN SEPSIS

摘要 革兰氏阴性脓毒症相关的急性肺损伤（ALI）的特征是中性粒细胞- 介导的炎症，表现出过度的发病率和死亡率。尽管改善了 支持性治疗，目前还没有基于分子水平的针对ALI的特异性治疗方法。 综合征的发病机制。我们的总体目标是确定肺动脉高压的信号机制， 调节中性粒细胞活化的巨噬细胞，中性粒细胞在介导肺 炎性损伤我们已经表明，抑制NADPH氧化酶活性会导致 抑制治疗的肺中的转录核因子κ B（NF-B）活化 与内毒素一起使用，而不减少细胞因子的产生或由 中性粒细胞在NADPH氧化酶缺陷小鼠中观察到的炎症增加机制 相对于wt没有定义。使用骨髓嵌合体p47 phox-/- wt小鼠， 我们观察到野生型小鼠的p47 phox-/-骨髓导致NF-B活化增强， 肺内嗜中性粒细胞炎症LPS激发。我们基于这些数据的中心假设是 NADPH氧化酶产生的ROS信号将巨噬细胞从亲- 内毒素血症期间的炎症表型。我们将讨论这种表型 通过NADPH氧化酶产生ROS激活氧化还原敏感的Src，林恩， 激酶，其进而激活含SH 2的磷脂酰肌醇磷酸酶-1（SHIP-1）。 在该模型中，林恩激酶和SHIP-1代表了增强PIP 3的关键信号传导节点 降解为PI（3，4）P2，其减弱Akt的活化，从而减弱NF-B的活化。该模型 将在目标1中进行询问，其中我们将确定NADPH氧化酶产生的 活性氧信号在巨噬细胞抗炎表型转换机制中的作用。 进一步在目标2中，我们将确定氧化还原激活的下游信号传导机制， NADPH氧化酶产生ROS介导巨噬细胞功能的转换， 从而确定巨噬细胞在减轻肺部炎症中的潜在重要作用， 损伤通过系统地阐明NADPH氧化酶在调节细胞功能中的作用， 肺巨噬细胞调节肺部炎症，我们应该确定新的信号通路 可以提供新的治疗方法来限制损伤。

ABSTRACT Acute lung injury (ALI) associated with Gram-negative sepsis is characterized by neutrophil- mediated inflammation that exhibits excessive morbidity and mortality. In spite of improved supportive care, there are currently no specific treatments for ALI that are based on the molecular pathogenesis of the syndrome. Our overall goal is to identify signaling mechanisms in pulmonary macrophages that regulate the activation of neutrophils that are crucial in mediating lung inflammatory injury. We have shown that inhibition of NADPH oxidase activity results in dampening of the transcription nuclear factor kappa B (NF-¿B) activation in lungs that are treated with endotoxin without a reduction in cytokine generation or inflammation mediated by neutrophils. The mechanisms of increased inflammation seen in NADPH oxidase-deficient mice relative to wt have not been defined. Using reciprocal bone marrow chimera p47phox-/- wt mice, we observed that p47phox-/- bone marrow in wt mice resulted in enhanced NF-¿B activation and neutrophilic inflammation in lungs LPS challenge. Our central hypothesis based on these data is that NADPH oxidase-generated ROS signaling converts macrophages from a pro- to anti- inflammatory phenotype during endotoxemia. We will address the postulate that this phenotype switch occurs via NADPH oxidase-generated ROS activation of a redox-sensitive Src, Lyn kinase, which in turn activate the SH2-containing phosphatidyl inositol phosphatase-1 (SHIP-1). In this model, Lyn kinase and SHIP-1 represent a critical signaling node that enhances PIP3 degradation to PI (3, 4) P2, which attenuates activation of Akt and thereby of NF-¿B. This model will be interrogated in Aim 1 in which we will determine the role of NADPH oxidase-generated ROS signaling in the mechanism of the anti-inflammatory phenotype switch in macrophages. Further in Aim 2, we will identify the redox-activated signaling mechanisms downstream of NADPH oxidase generation of ROS in mediating the conversion in macrophage function and thereby identify the potentially important role of macrophages in mitigating lung inflammatory injury. By systematically delineating the role of NADPH oxidase in regulating the function of lung macrophages in modulating lung inflammation, we should identify novel signaling pathways that could provide novel therapeutic approaches to limit the injury.