Inflammasomes: Regulation and Function in Acute Lung Injury

项目摘要/摘要 患有急性呼吸窘迫综合征(ARDS)的患者经常需要机械通气(MV)， 进一步导致肺损伤(呼吸机诱导的肺损伤，VILI)。VILI与相当大的发病率有关 以及有无ARDS的机械通气患者的死亡率。肺炎(PA)是主要的 人类发生ARDS的危险因素。在啮齿动物中，VILI和PA已被广泛用作 建立实验性急性肺损伤(ALI)模型，研究ARDS的发病机制。这其中的科学前提是 受体相互作用蛋白-3激酶(RIPK3)在坏死性细胞死亡过程中起着至关重要的作用 和炎症在实验性ALI(VILI和PA模型)的发病机制中以及在人类疾病中 阿兹。我们已经获得了有趣的初步数据，证明RIPK3在ALI中表达受到调控， RIPK3基因缺陷的小鼠对ALI有保护作用(在VILI和PA模型中)，强烈表明 RIPK3依赖的坏死性下垂通路在实验性ALI的发病机制中起着至关重要的作用。 我们进一步表明，代谢功能障碍，如失调的脂肪酸(FA)代谢会导致 RIPK3依赖的信号通路激活和坏死性下垂及FA代谢障碍促进 巨噬细胞炎性小体激活和促炎细胞因子的产生，这有助于 阿里的发展。我们还表明，FA合成和线粒体NADPH：氧化酶-4(NOX4)是 NLRP3介导的巨噬细胞炎性小体激活所必需的。在人体研究中，我们证明了 不仅炎症组调节的细胞因子与危重病人的死亡率有关，而且 在重症患者中，坏死性下垂蛋白RIPK3和FA都受到调节。基于这些研究， 我们提出以下假设：无菌损伤性机械通气或肺炎感染是原因 代谢和FA功能障碍导致RIPK3依赖的信号通路激活和坏死性下垂。颠覆 机械损伤或感染对FA代谢的影响促进巨噬细胞NOX4依赖的炎症体 活化和促炎细胞因子的产生，参与了ALI的发生发展。我们也 假设坏死性下垂相关蛋白和FA与患者的发病率和死亡率有关 患有危重疾病，包括急性呼吸窘迫综合征。我们将通过解决以下具体目标来验证我们的假设： 具体目的1：探讨RIPK3依赖的坏死性下垂在ALI中的调节和作用。特定目标 2：确定坏死性下垂介导NOX4依赖的NLRP3炎症体的机制 在ALI中激活。具体目标3：确定坏死性下垂与FA代谢的临床相关性。 危重病人，包括急性呼吸窘迫综合征。

PROJECT SUMMARY/ABSTRACT Patients with acute respiratory distress syndrome (ARDS) often require mechanical ventilation (MV), which further induces lung injury (ventilator-induced lung injury, VILI). VILI is associated with substantial morbidity and mortality both in mechanically ventilated patients with, and without ARDS. Pneumonia (PA) is a primary risk factor for development of ARDS in humans. In rodents, VILI and PA have been extensively used as experimental acute lung injury (ALI) models to study the pathogenesis of ARDS. The scientific premise of this grant is that receptor-interacting protein-3 kinase (RIPK3) is crucial for the propagation of necroptotic cell death and inflammation in the pathogenesis of experimental ALI (VILI and PA models) and in human disease such as ARDS. We have obtained intriguing preliminary data demonstarting that RIPK3 expression is regulated in ALI, and that RIPK3-deficient mice are protected against ALI (in both VILI and PA models), strongly suggesting that the RIPK3-dependent necroptosis pathway is crucial for mediating the pathogenesis of experimental ALI. We further show that metabolic dysfunction such as dysregulated fatty acid (FA) metabolism results in activation of RIPK3-dependent signaling and necroptosis and that disruption of FA metabolism promotes macrophage inflammasome activation and pro-inflammatory cytokines production, which contributes to the development of ALI. We also show also that FA synthesis and mitochondrial NADPH:oxidase-4 (NOX4) are required for NLRP3-mediated inflammasome activation in macrophages. In human studies, we demonstrate that not only are inflammasome regulated cytokines associated with mortality of the critically ill patients but both necroptosis proteins RIPK3 and FA are regulated in patients with critical illness. Based on these studies, we propose the following hypothesis: Sterile injurious mechanical ventilation or pneumonia infection causes metabolic and FA dysfunction resulting in activation of RIPK3-dependent signaling and necroptosis. Disruption of FA metabolism by mechanical injury or infection promotes macrophage NOX4-dependent inflammasome activation and pro-inflammatory cytokines production, which contribute to the development of ALI. We also hypothesize that necroptosis-related proteins and FA are associated with morbidity and mortality in patients with critical illness, including ARDS. We will test our hypothesis by addressing the following Specific Aims: Specific Aim 1: To determine the regulation and function of RIPK3-dependent necroptosis in ALI. Specific Aim 2: To determine the mechanisms by which necroptosis mediates NOX4-dependent NLRP3 inflammasome activation in ALI. Specific Aim 3: To determine the clinical relevance of necroptosis and FA metabolism in the critically ill patients, including ARDS.