Role of the Na K ATPase Beta 1 subunit in alveolar epithelial integrity

Na K ATPase Beta 1 亚基在肺泡上皮完整性中的作用

基本信息

批准号：
9069957
负责人：
Laura Andrea Dada
金额：
$ 35.04万
依托单位：
NORTHWESTERN UNIVERSITY AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-08-01 至 2017-11-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9069957
关键词：
Active Biological Transport Acute Lung Injury Adherens Junction Adhesions Alveolar Alveolus Amino Acids Cell Adhesion Molecules Cell Communication Cell membrane Cell-Cell Adhesion Cells Clinical Complication Cytoskeleton Data Detergents Diffusion Edema Endoplasmic Reticulum Enzymes Epithelial Epithelial Cells Epithelium Exposure to Family Gases Health Hypoxia Impairment In Vitro Integral Membrane Protein Intercellular Junctions Ion Transport Lead Lectin Lentivirus Vector Life Link Liquid substance Lung Mediating Molecular Molecular Chaperones Mus Na(+)-K(+)-Exchanging ATPase Outcome Pathway interactions Permeability Polysaccharides Process Proteins Pulmonary Edema Pump Resistance Resolution Role Site-Directed Mutagenesis Stimulus Structure Testing Tissues Up-Regulation alveolar epithelium biological adaptation to stress dimer dysadherin effective therapy improved in vivo inhibitor/antagonist insight lung injury monolayer overexpression prevent research study sodium ion

项目摘要

DESCRIPTION (provided by applicant): Lung edema is a life-threatening complication of lung injury. The active transepithelial Na+ ion transport performed in part by the alveolar epithelial Na,K-ATPase is critical for lung edema clearance. Edema impairs gas exchange, which leads to alveolar hypoxia. Hypoxia, in turn, impairs intercellular adhesion and decreases the amount of the Na,K-ATPase at the plasma membrane, worsening clinical outcomes. The minimal functional unit of the Na,K-ATPase is a dimer consisting of an α and a β subunit, which not only transports ions, but also acts as a cell adhesion molecule. FXYD5 is a one of the 7 tissue-specific regulatory subunits of the Na,K- ATPase activity, which is also implicated in the impairment of intercellular junctions. In preliminary experiments, we observed that hypoxia impairs intercellular adhesion and up-regulates FXYD5 in alveolar epithelial cells. We hypothesize that the Na,K-ATPase is important for modulating the integrity of the alveolar epithelium by strengthening cell-cell contacts due to the interaction between the Na,K-ATPase β1 subunits of neighboring alveolar epithelial cells and by weakening these contacts by FXYD5- mediated impairment of β1:β1 bridges during hypoxia. In specific aim # 1, we will determine whether the interactions between the Na,K-ATPase β1 subunits of neighboring alveolar epithelial cells are impaired by hypoxia We will determine whether modulating β1:β1 interactions by removing N-glycans or modifying their structure alters cell-cell adhesion during normoxic and hypoxic conditions in vitro or in vivo. In specific aim #2, we will determine whether FXYD5 up-regulation during hypoxia impairs β1:β1 interactions. By over-expressing or silencing of FXYD5 in lung epithelial cells, in both normal and hypoxic conditions, we will determine whether FXYD5 contributes to hypoxia-induced impairment of intercellular adhesion by disrupting the interaction between the Na,K-ATPase β subunits of neighboring cells in vitro or in vivo. In specific aim #3, we will investigate chaperone-assisted maturation pathways of the Na,K-ATPase in the endoplasmic reticulum (ER) of alveolar epithelial cells in normal conditions and during hypoxia. In experiments performed for this proposal, we observed that hypoxia results in significant retention of the Na,K-ATPase in the ER of alveolar epithelial cells and thus decreases its abundance in the plasma membrane, which would impair edema fluid clearance and barrier function. We will determine whether up-regulation of ER chaperones by N-glycan processing inhibitor, castanospermine, rescues the maturation of the Na,K-ATPase and whether application of this inhibitor prior to exposure of mice to hypoxia improves barrier function. The proposed studies will provide insights into non- canonical roles of the Na,K-ATPase in stabilization of cell cell contacts, which are crucial for normal function of alveolar epithelia. Understanding the mechanism(s) underlying chaperone-assisted maturation of the Na,K- ATPase in alveolar epithelial cells and finding the means to prevent ER retention of the enzyme during hypoxia may lead to more effective treatment for pulmonary edema and acute lung injury.

描述（通过应用证明）：肺水肿是肺部NA的一种威胁生命的并发症。损害细胞间的粘合剂，并减少Na的Na临床结局的量Na，K- ATPase活性也与初步实验中的细胞间连接症相关。由于Na，K-ATPaseβ1亚基的相互作用，通过β1：β1：β1桥梁弱化了这些接触，因此在肺泡中的相互作用是由肺泡c的模块特定的目标＃1，邻近肺泡细胞的K-ATPaseβ1亚基是IMPAIREA，我们将通过在体外或体内进行Normogoxic和dypoxic条件下通过emove n-glycans或修饰其结构来改变细胞细胞粘附，我们将确定在缺氧期间的FXYD5上调会损害β1：β1的相互作用或在正常和低氧条件下FXYD5 UNG上皮细胞的相互作用或沉默，我们将确定FXYD5是否有助于低氧诱导症状 - 通过na降低症状障碍。，在特定目标3中，邻近细胞的K-ATPaseβ亚基。在实验中进行的缺氧。 ClearID屏障功能将确定N-聚糖抑制剂Castanospermine对ER伴侣的上调是否可以挽救Na，K-ATPase的成熟，以及在小鼠暴露于Hypoxia Imboxia Imboxia震源之前的TIS抑制剂的应用。在稳定细胞中细胞接触是肺泡上皮的至关重要的形式功能，在肺泡上皮细胞中的K-ATPase，在缺氧期间找到产生的酶的手段可能会导致对肺水肿和急性肺损伤的更有效的信任。