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：
8438932
负责人：
Laura Andrea Dada
金额：
$ 34.74万
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 2017-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8438932
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 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 prevent public health relevance 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 ¿ and a ¿ 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 ¿1 subunits of neighboring alveolar epithelial cells and by weakening these contacts by FXYD5- mediated impairment of ¿1:¿1 bridges during hypoxia. In specific aim # 1, we will determine whether the interactions between the Na,K-ATPase ¿1 subunits of neighboring alveolar epithelial cells are impaired by hypoxia We will determine whether modulating ¿1:¿1 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 ¿1:¿1 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 ¿ 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。损害细胞间粘合剂，并减少Na临床结果的量。和一个亚基的作用是Asashesion分子，K-ATPase活性也与初步实验的障碍有关Na，通过在Na，K-ATPase»之间加强细胞接触，以实现肺泡上皮的模量。 1个相邻肺泡上皮细胞的亚基，并通过FXYD5介导的损害削弱这些接触。 1：¿在特定目的1中的1个桥梁。 1个相邻肺泡脊柱细胞的亚基受到损害，将确定是否调节�是否调节1：¿ 1通过消除n-glycang的结构，在体外或体内的正常氧和低氧条件下，所有细胞都有粘合。 1：¿ 1相互作用。在正常条件下和缺氧过程中，邻近的细胞在体外或体内的体内。，质子L细胞中的K-ATPase在质膜中的含量是丰富的，这会损害水肿流体清除率和屏障功能。见解洞察力的见解将使Na，k-atpase在稳定细胞中的非典型作用。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。