Role and Regulation of Sodium, Potasium ATPase in Lung

钠、钾 ATP 酶在肺中的作用和调节

• 批准号: 7559563
• 负责人: Jacob I Sznajder
• 金额: $ 37.97万
• 依托单位: NORTHWESTERN UNIVERSITY AT CHICAGO
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7559563
• 关键词: A549; ATP phosphohydrolase; Actins; Adrenergic Agents; Adult Respiratory Distress Syndrome; Affect; Agonist; Alveolar; Apical; Applications Grants; Breathing; Cell membrane; Cells; Cytoskeleton; Data; Dopamine Agonists; Dynein ATPase; Edema; Epithelial; Epithelial Cells; Etiology; Family; Funding; G-Protein-Coupled Receptors; Grant; Human; Human body; Isoenzymes; Kinesin; Lead; Liquid substance; Lung; Mediating; Microfilaments; Microtubules; Molecular Motors; Mus; Myosin ATPase; Myosin Type V; Na(+)-K(+)-Exchanging ATPase; Organ; Oxygen; Patients; Proteins; Public Health; Pulmonary Edema; Rattus; Regulation; Rodent; Rodent Model; Role; Sodium; Syndrome; Type II Epithelial Receptor Cell; Up-Regulation; Vesicle; adrenergic; alveolar epithelium; base; design; improved; injured; lung injury; mortality; novel strategies; novel therapeutics; research study; salt-inducible kinase; trafficking

DESCRIPTION (provided by applicant): Acute respiratory distress syndrome (ARDS) can occur in patients from multiple etiologies. A hallmark of this syndrome is lung injury and edema which results in impaired oxygenation. Alveolar edema clearance needs to occur for the patients to improve. Recently, it has been recognized that the mechanisms responsible for alveolar fluid clearance in patients with ARDS are impaired, which is associated with increased mortality. Alveolar fluid clearance is affected mostly by vectorial Na+ transport, via apical Na+ channels and basolateral Na,K-ATPase in the alveolar epithelium. Thus, a better understanding of the regulation of active Na+ transport may lead to new therapeutic strategies to improve edema clearance and reduce mortality of patients with ARDS. In previous cycles of this grant, we have determined that upregulation of the (-2 and (-1 subunits of the Na+ pump increased Na,K-ATPase function in alveolar epithelial cells (AEC) and increased lung edema clearance. We have also determined that G-protein coupled receptors (GPCR) agonists increased Na,K-ATPase function which lead to increased alveolar fluid clearance. However, the mechanisms regulating GPCR-mediated upregulation of the Na,K-ATPase have not been fully elucidated. In this current proposal we will focus on the mechanisms regulating the GPCR mediated increase in Na,K-ATPase function and alveolar fluid reabsorption via three interrelated specific aims: in studies proposed for Specific Aim 1 we will determine whether the salt inducible kinase (SIK) participates in the GPCR mediated Na,K-ATPase upregulation by facilitating the traffic of Na+ pump molecules from intracellular pools into the AEC plasma membrane; in studies pertaining to Specific Aim 2, we will determine the role of actin-based molecular motors and specifically the role of the myosin V family in the traffic of Na,K-ATPase vesicles and thus Na,K-ATPase upregulation via its recruitment to the plasma membrane of alveolar epithelial cells; and in experiments pertaining to Specific Aim 3, we will determine whether the intracellular trafficking of Na,K-ATPase during recruitment to the plasma membrane is regulated by the cytoskeleton-microtubule molecular motors, kinesin and dynein. Experiments have been conducted for each of the specific aims and the preliminary data support the feasibility of the proposed experiments. The data generated from the proposed studies will provide important new information on the role and regulation of Na,K-ATPase and active Na+ transport in rodent lungs which will help with the design of new strategies to increase lung edema clearance in patients with the acute respiratory distress syndrome. Relevance to Public Health: Patients with acute respiratory distress syndrome (ARDS) have lung injury and fluid (edema) accumulation in their airspaces. This fluid in their lungs precludes them from breathing normally as it impairs the transfer of oxygen from the room through the lungs and into all the organs of the human body. For the patient with ARDS to survive the fluid from the lungs needs to be cleared. The protein sodium/potasium adenyl triphosphatase (Na,K-ATPase) has an important role in fluid clearance from the lungs such that when more Na,K-ATPase molecules are present at the lung epithelial cell membrane it increases fluid clearance from normal and injured lungs. In this grant application we propose to study mechanisms by which Na,K-ATPase can be increased in the lung epithelial cell membranes leading to increased fluid clearance from the lungs. The results from the proposal should be of importance to design novel strategies to treat patients with ARDS such as the ones conducted by the ARDSnet.

描述（由申请人提供）：多种病因的患者可能会出现急性呼吸窘迫综合征（ARDS）。该综合征的一个标志是肺损伤和水肿，导致氧合受损。患者需要清除肺泡水肿才能得到改善。最近，人们认识到 ARDS 患者负责肺泡液清除的机制受损，这与死亡率增加相关。肺泡液清除主要受到矢量 Na+ 转运的影响，通过肺泡上皮中的顶端 Na+ 通道和基底外侧 Na,K-ATP 酶。因此，更好地了解主动 Na+ 转运的调节可能会带来新的治疗策略，以改善水肿清除并降低 ARDS 患者的死亡率。在本资助的前几个周期中，我们已经确定 Na+ 泵的 (-2 和 (-1) 亚基的上调可增加肺泡上皮细胞 (AEC) 中的 Na,K-ATP 酶功能并增加肺水肿清除。我们还确定G 蛋白偶联受体 (GPCR) 激动剂可增加 Na,K-ATP 酶功能，从而导致肺泡液清除率增加。然而，调节 GPCR 介导的 Na,K-ATP 酶上调的机制已被证实。在当前的提案中，我们将通过三个相互关联的具体目标，重点关注调节 GPCR 介导的 Na,K-ATP 酶功能增加和肺泡液重吸收的机制：在针对具体目标 1 提出的研究中，我们将确定盐是否存在。在与特定相关的研究中，诱导激酶 (SIK) 通过促进 Na+ 泵分子从细胞内库进入 AEC 质膜来参与 GPCR 介导的 Na,K-ATP 酶上调；目标 2，我们将确定基于肌动蛋白的分子马达的作用，特别是肌球蛋白 V 家族在 Na,K-ATP 酶囊泡运输中的作用，从而通过其招募到肺泡质膜来上调 Na,K-ATP 酶上皮细胞；在与特定目标 3 有关的实验中，我们将确定 Na,K-ATP 酶在招募到质膜期间的细胞内运输是否受到细胞骨架-微管分子马达、驱动蛋白和动力蛋白的调节。针对每个具体目标进行了实验，初步数据支持所提出实验的可行性。拟议研究产生的数据将为啮齿类动物肺部中 Na,K-ATP 酶和活性 Na+ 转运的作用和调节提供重要的新信息，这将有助于设计新策略，以增加急性呼吸道疾病患者的肺水肿清除率苦恼综合症。与公共卫生的相关性：急性呼吸窘迫综合征 (ARDS) 患者有肺损伤和气腔积液（水肿）。肺部的这种液体会妨碍他们正常呼吸，因为它会损害氧气从房间通过肺部进入人体所有器官的传输。对于急性呼吸窘迫综合征（ARDS）患者来说，为了生存，需要清除肺部的液体。蛋白钠/钾腺苷三磷酸酶 (Na,K-ATP 酶) 在肺部液体清除中发挥重要作用，因此，当肺上皮细胞膜上存在更多 Na,K-ATP 酶分子时，它会增加正常和受损的液体清除肺。在这项拨款申请中，我们建议研究肺上皮细胞膜中 Na,K-ATP 酶增加的机制，从而增加肺部液体清除率。该提案的结果对于设计治疗 ARDS 患者的新策略（例如 ARDSnet 实施的策略）具有重要意义。