Mucociliary Function in Chronic Bronchitis

慢性支气管炎的粘膜纤毛功能

• 批准号: 7297691
• 负责人: Matthias A Salathe
• 金额: $ 38.25万
• 依托单位: UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-01 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7297691
• 关键词: ATP Hydrolysis; Acids; Adenosine; Affect; Apical; Arts; Biological Assay; Biology; Blocking Antibodies; Calcium; Calcium Oscillations; Cells; Chronic Bronchitis; Condition; Connexins; Cyclic AMP; Data; Disease; Epithelial Cells; Feedback; Frequencies; Functional disorder; Gap Junctions; Glycosaminoglycans; Goals; HMMR gene; Height; Hyaluronan; Hyaluronic Acid; Image; In Situ; In Vitro; Inflammation; Inflammatory; Intracellular Second Messenger; Liquid substance; Measures; Mechanical Stress; Mediating; Mediator of activation protein; Methods; Mucociliary Clearance; NADPH Oxidase; Pathway interactions; Physiological; Play; Production; Property; Proteins; Purinergic P1 Receptors; Purinoceptor; Reactive Oxygen Species; Regulation; Research Personnel; Reverse Transcriptase Polymerase Chain Reaction; Role; Second Messenger Systems; Signal Pathway; Signal Transduction; Small Interfering RNA; Stimulus; Surface; System; Testing; Up-Regulation; Xanthine Oxidase; Xanthines; airway epithelium; airway inflammation; airway surface liquid; apical membrane; cell motility; cytokine; extracellular; fighting; human MST1R protein; improved; inhibitor/antagonist; insight; macrophage stimulating protein; molecular size; novel; paracrine; prevent; receptor; research study; response; xanthine

DESCRIPTION (provided by applicant): In chronic bronchitis, mucociliary clearance is dysfunctional, especially during disease exacerbation. Chronic bronchitis exacerbations are commonly associated with increased production of reactive oxygen species (ROS) and airway acidification. This project will examine how ROS and intracellular acidification may regulate and/or dysregulate mucociliary function. At least two endogenous and paracrine mediators control key components of the mucociliary transport system: extracellular ATP and hyaluronan fragments. We propose that pannexins, proteins related to but different from connexins, form channels to the outside of cells (called pannexons) and are responsible, at least in part, for the release of apical ATP in the airway epithelium. We hypothesize that early in disease exacerbation, the production of ROS not only increases intracellular calcium concentrations ([Ca2+]i) to stimulate ciliary beat frequency (CBF) and apical ATP release through pannexons but also degrades apical hyaluronan which in turn stimulates CBF and increases airway surface liquid (ASL) volume. Subsequent intracellular acidification, possibly mediated by cytokine-mediated upregulation of an NADPH oxidase activity expressed in the airway (Duox), leads to mucociliary dysfunction by inhibiting ciliary activity and pannexins. This hypothesis will be tested with three specific aims. Specific Aim 1 will test the hypothesis that exogenous ROS activate a signaling cascade that includes an initial [Ca2+]i increase to stimulate CBF, despite a mild and temporary intracellular acidification due to H+ production by Duox; in addition, direct apical hyaluronan degradation activates RHAMM and RON to stimulate CBF and possibly increase ASL volume. Specific Aim 2 will test the hypothesis that pannexins are responsible for releasing ATP to the apical surface of airway epithelial cells where ATP plays an important role in regulating mucociliary functions including CBF and ASL volume. Specific Aim 3 will test the hypothesis that persistent intracellular acidification inhibits mucociliary clearance by a direct action on ciliary beating as well as by preventing ATP release through pannexons. The results of the proposed experiments, using novel and state-of-the-art methods, will provide new and important mechanistic insights into the regulation of mucociliary clearance in chronic bronchitis.

描述（由申请人提供）：在慢性支气管炎中，粘液纤毛清除功能障碍，尤其是在疾病恶化期间。慢性支气管炎恶化通常与活性氧（ROS）产生增加和气道酸化有关。该项目将研究活性氧和细胞内酸化如何调节和/或失调粘膜纤毛功能。至少两种内源性和旁分泌介质控制着粘膜纤毛转运系统的关键成分：细胞外 ATP 和透明质酸片段。我们认为，pannexins 是与连接蛋白相关但又不同的蛋白质，形成通向细胞外部的通道（称为 pannexons），并且至少部分负责气道上皮中顶端 ATP 的释放。我们假设，在疾病恶化的早期，ROS的产生不仅增加细胞内钙浓度（[Ca2+]i）以刺激纤毛搏动频率（CBF）和通过pannexon释放顶端ATP，而且还降解顶端透明质酸，从而刺激CBF并增加气道表面液体（ASL）体积。随后的细胞内酸化可能是由细胞因子介导的气道中表达的 NADPH 氧化酶活性上调 (Duox) 介导的，通过抑制纤毛活性和 pannexins 导致粘液纤毛功能障碍。该假设将通过三个具体目标进行检验。具体目标 1 将检验以下假设：尽管 Duox 产生 H+ 导致细胞内轻度暂时酸化，但外源 ROS 激活信号级联，其中包括初始 [Ca2+]i 增加以刺激 CBF；此外，直接顶端透明质酸降解会激活 RHAMM 和 RON，从而刺激 CBF 并可能增加 ASL 体积。具体目标 2 将检验以下假设：pannexins 负责将 ATP 释放到气道上皮细胞的顶端表面，其中 ATP 在调节粘膜纤毛功能（包括 CBF 和 ASL 体积）中发挥重要作用。具体目标 3 将检验以下假设：持续的细胞内酸化通过对纤毛跳动的直接作用以及通过 pannexons 阻止 ATP 释放来抑制粘膜纤毛清除。所提出的实验结果使用新颖且最先进的方法，将为慢性支气管炎粘液纤毛清除的调节提供新的、重要的机制见解。