NADPH OXIDASE REGULATION OF THE MACROPHAGE INFLAMMATORY PHENOTYPE IN SEPSIS

摘要 与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- 介导性炎症表现出过高的发病率和死亡率。尽管改进了 支持性护理，目前还没有针对ALI的基于分子的特定治疗方法 本病的发病机制。我们的总体目标是确定肺组织中的信号机制。 调节中性粒细胞激活的巨噬细胞，中性粒细胞在调节肺功能中起关键作用 炎症性损伤。我们已经证明，抑制NADPH氧化酶的活性会导致 抑制肺组织中转录核因子-kappaB的活性(英文) 内毒素，而不减少细胞因子的产生或由 中性粒细胞。NADPH氧化酶缺陷小鼠炎症增加的机制 相对于wt尚未定义。使用相互的骨髓嵌合体p47Phox-/-wt小鼠， 我们观察到wt小鼠的p47Phox-/-骨髓导致核因子-βB的激活增强，并 中性粒细胞炎症在肺内毒素攻击。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核转化为抗核 内毒素血症时的炎症表型。我们将讨论这种表型的假设 开关通过NADPH氧化酶产生的ROS激活氧化还原敏感的Src，Lyn而发生 进而激活含SH2的磷脂酰肌醇磷酸酶-1(SHIP-1)。 在该模型中，Lyn激酶和Ship-1代表了增强PIP3的关键信号节点 降解到PI(3，4)P2，从而减弱Akt的激活，从而减弱NF-B的激活。该模型 将在目标1中被审问，在其中我们将确定NADPH氧化酶产生的作用 ROS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信号机制下游 ROS在介导巨噬细胞功能转化中的NADPH氧化酶生成 从而确定巨噬细胞在减轻肺部炎症中的潜在重要作用 受伤。通过系统地描述NADPH氧化酶在调节细胞周期中的作用 肺巨噬细胞在调节肺部炎症中应识别新的信号通路 这可能会提供新的治疗方法来限制伤害。

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.