Role of LUBAC and Na K-ATPase in Acute Lung Injury

项目摘要 急性肺损伤和急性呼吸窘迫综合征（ARDS）患者的气体交换受损 这是由于肺泡上皮功能改变，导致水肿液积聚，导致缺氧。 肺泡缺氧在ARDS患者中很常见，并导致肺泡上皮功能障碍。季节性 流感感染影响美国和世界范围内相当大比例的人口， 虽然大多数感染甲型流感的患者康复无后遗症，但在一些患者中， 感染可引起严重的肺炎和ARDS。肺泡上皮细胞是甲型流感病毒的靶细胞， 并且在安装初始宿主响应中起重要作用。甲型流感病毒感染后，肺泡 上皮细胞释放有助于单核细胞和巨噬细胞募集到该部位的细胞因子 同时也参与病毒清除，这可能会限制感染的传播。但 这些事件的潜在机制尚未完全了解。我们假设，除了它的 作为一种屏障功能，肺泡上皮细胞在保护肺免受严重的 损伤这项赠款建议的第一个目的是阐明导致稳定的机制， Na，K-ATPase在缺氧时作为对应激的适应，从而促进细胞存活。 我们将研究E3对PKC β 1的降解是否会引起Na，K-ATP酶的下调， 连接酶HOIL-1 L降低慢性缺氧时肺泡上皮细胞死亡和肺损伤。HOIL-1 L是一种 Linear Ubiquitination Assembly Complex（LUBAC）的缩写。在为第二个具体目标提出的研究中， 目的：我们将评估LUBAC是否参与肺炎症强度的调节 在流感病毒感染期间的上皮。第三个具体目标审查了 增加的细胞内钠浓度，这发生在Na，K-ATP酶的适度抑制期间， 防止肺泡上皮细胞中的病毒复制，以及是否对Na，K-ATP酶的药理学抑制 通过强心类固醇如哇巴因和地高辛代表一种保护机制， 复制的了解缺氧导致肺泡上皮功能障碍的机制， 流感病毒感染将提供具有临床意义的新信息， 急性肺损伤患者治疗的创新方法。

PROJECT SUMMARY Patients with acute lung injury and Acute Respiratory Distress Syndrome (ARDS) have impaired gas exchange due to altered alveolar epithelial function, which results in accumulation of edema fluid leading to hypoxia. Alveolar hypoxia is common in patients with ARDS and contributes to alveolar epithelial dysfunction. Seasonal influenza infection affects a significant proportion of the population in the United States and worldwide, and while most patients infected with influenza A recover without sequelae, in some patients influenza virus infection may cause severe pneumonitis and ARDS. Alveolar epithelial cells are targets for influenza virus A, and play an important role in mounting the initial host response. Upon influenza A virus infection, alveolar epithelial cells release cytokines that contribute to the recruitment of monocytes and macrophages to the site of infection and also participate in viral clearance, which may limit the infection from spreading. However, the underlying mechanisms of these events are not completely understood. We hypothesize that in addition to its barrier function, the alveolar epithelium plays an important effector role in protecting the lung from severe injury. The first aim of this grant proposal seeks to elucidate the mechanisms that lead to the stabilization of Na,K-ATPase plasma membrane levels during hypoxia as an adaptation to stress, thus promoting cell survival. We will study whether the degradation of PKCζ, which triggers the down-regulation of Na,K-ATPase, by the E3 ligase HOIL-1L decreases alveolar epithelial cell death and lung injury during chronic hypoxia. HOIL-1L is a member of the Linear Ubiquitination Assembly Complex (LUBAC). In studies proposed for the second specific aim, we will assess whether LUBAC participates in the modulation of the inflammatory intensity in the lung epithelium during influenza virus infection. The third specific aim examines the mechanisms by which increased intracellular sodium concentration, which occurs during modest inhibition of the Na,K-ATPase, prevents viral replication in alveolar epithelial cells and whether pharmacologic inhibition of the Na,K-ATPase by cardiotonic steroids such as ouabain and digoxin represents a protective mechanism by inhibiting virus replication. Understanding the mechanism(s) that lead to alveolar epithelial dysfunction caused by hypoxia and influenza virus infection will provide novel information that is of clinical relevance and has the potential for innovative approaches in the treatment of patients with acute lung injury.