Regulation of alveolar epithelial barrier function by claudins

密蛋白对肺泡上皮屏障功能的调节

• 批准号: 7867413
• 负责人: JAMES A FRANK
• 金额: $ 30.85万
• 依托单位: NORTHERN CALIFORNIA INSTITUTE/RES/EDU
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7867413
• 关键词: Acute Lung Injury; Adult Respiratory Distress Syndrome; Alveolar; Binding; Biological; Chloride Ion; Chlorides; Clostridium perfringens enterotoxin; Data; Development; Edema; Environmental air flow; Epidermal Growth Factor Receptor; Epithelial; Epithelial Cells; Family; Fluid Balance; Functional disorder; Gene Proteins; Human; In Vitro; Ion Transport; Ions; Laboratories; Light; Liquid substance; Lung; Measurement; Measures; Mediator of activation protein; Modeling; Movement; Mus; Pathway interactions; Patients; Peptides; Permeability; Play; Property; Protein Family; Proteins; Pulmonary Edema; RNA Interference; Rattus; Receptor Activation; Regulation; Research; Respiratory Failure; Role; Severities; Small Interfering RNA; Sodium; Stimulus; Tidal Volume; Tight Junctions; Time; Transplantation; Type II Epithelial Receptor Cell; Ventilator; Ventilator-induced lung injury; Work; alveolar type II cell; claudin 4; in vivo; inhibitor/antagonist; insight; lung injury; mortality; mouse model; novel therapeutics; physical property; protein expression; research study; response

DESCRIPTION (provided by applicant): Acute Respiratory Distress Syndrome (ARDS), the most severe form of acute lung injury, is a common cause of respiratory failure with an overall mortality rate of nearly 40%; however, there are currently no specific pharmacological therapies. A hallmark of ARDS is increased alveolar barrier permeability and decreased clearance of fluid from the airspaces resulting in pulmonary edema. Although work by our group and others has begun to shed light on the regulation of transcellular epithelial ion transport, much less is known about how paracellular permeability and ion transport are regulated in acute lung injury. New research into the regulation of paracellular permeability and selective transport through tight junctions is of fundamental importance to understanding epithelial function in ARDS. In preliminary studies, we have found that tight junction claudins are differentially expressed in acute lung injury. Differential regulation of the claudin family of proteins may represent a central mechanism by which epithelial cells alter the physical properties of the paracellular pathway to control permeability and ion movement. Our hypothesis is that alveolar epithelial cells control the particular tight junction claudins expressed in response to environmental stimuli. We found a significant increase in claudin 4 expression during acute lung injury. This may represent an adaptive response to limit airspace edema formation and allow higher rates of edema clearance because claudin 4 decreases paracellular permeability to large molecules and favors a paracellular pathway that excludes sodium but allows chloride transport. These properties would promote airspace fluid clearance. In Aim 1, we will determine the functional contribution of claudin 4 to tight junctions using a peptide inhibitor and RNAi in primary rat and human alveolar epithelial type II cells. We will also determine the mechanisms by which claudin 4 and other tight junction protein expression is regulated. In Aim 2, we will study the function and regulation of claudin 4 in our mouse model of ventilator-induced lung injury. In Aim 3, we will for the first time examine expression of several claudins in human lungs rejected for transplantation and, using our perfused human lung model, correlate expression levels with measures of epithelial function ex vivo. These studies will provide a more complete understanding of the mechanisms of alveolar epithelial barrier regulation during lung injury and facilitate the development of new therapeutic strategies for ARDS patients.

描述（由申请人提供）：急性呼吸窘迫综合征（ARDS）是最严重的急性肺损伤形式，是呼吸衰竭的常见原因，总死亡率接近40％；但是，目前尚无特定的药理疗法。 ARDS的标志是肺泡屏障的渗透率增加，并从空体中降低了流体的清除，导致肺水肿。尽管我们的小组和其他人的工作已经开始阐明跨细胞上皮离子转运的调节，但对于细胞细胞渗透性和离子转运如何在急性肺损伤中调节的知之甚少。对细胞细胞通透性和通过紧密连接的选择性运输的调节的新研究对于理解ARDS中的上皮功能至关重要。在初步研究中，我们发现紧密的连接claudins在急性肺损伤中差异表达。克劳丁蛋白家族的差异调节可能代表一种中心机制，上皮细胞通过该机制改变了控制渗透性和离子运动的细胞细胞途径的物理特性。我们的假设是，肺泡上皮细胞控制着针对环境刺激的特定紧密连接claudins。我们发现在急性肺损伤期间，Claudin 4表达显着增加。这可能代表自适应反应，以限制空域水肿的形成并允许更高的水肿清除率，因为Claudin 4降低了细胞细胞的通透性对大分子，并有利于排除钠的细胞细胞途径，但允许氯化物的运输。这些特性将促进空域流体清除率。在AIM 1中，我们将使用肽抑制剂和RNAi在原代大鼠和人肺泡上皮II型细胞中使用肽抑制剂和RNAi的紧密连接的功能贡献。我们还将确定Claudin 4和其他紧密连接蛋白表达的机制。在AIM 2中，我们将研究Claudin 4在呼吸机诱导的肺损伤模型中的功能和调节。在AIM 3中，我们将首次研究拒绝移植的人类肺中几种Claudins的表达，并使用我们灌注的人类肺模型将表达水平与上皮功能的量度相关联。这些研究将为肺损伤期间肺泡上皮屏障调节的机制提供更完整的了解，并促进为ARDS患者开发新的治疗策略。