Regulatory mechanisms of fluid clearance and lung function by alveolar ion channels

肺泡离子通道对液体清除和肺功能的调节机制

• 批准号: RGPIN-2016-04378
• 负责人: Brochiero, Emmanuelle
• 金额: $ 2.26万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=684046
• 关键词: Regulatory; mechanisms; fluid; clearance; lung

Lung function is dependent on alveolar epithelial cells that are responsible for surfactant production and transepithelial ion/liquid transport. Indeed, fluid clearance is required to maintain alveolar spaces virtually free of liquid, which is necessary for gas exchange. It has been established that liquid absorption is mainly driven by active ion transport through the Na+ channel ENaC. However, the complex regulatory mechanisms of ENaC and Na+/fluid transport remain incompletely understood.***Over the terms of our previous NSERC grants, we have made significant progress in the understanding of the mechanisms regulating ENaC channels and Na+/liquid transport through primary alveolar type II (ATII) cells. Our work also unveiled another class of channels, i.e. K+ channels (KCh, namely KATP and KvQT1 channels) that regulates ENaC expression via changes in promoter activity and participate in the control of Na+/liquid absorption. Finally, we have implemented an integrative murine model to study the clearance of fluids and lung function parameters. Our preliminary in vivo data indicated a relationship between ENaC and KCh and a control of alveolar fluid clearance, surfactant expression and lung compliance by KCh. We now propose to pursue our research program to dissect the complementary roles of ENaC and KCh in the control of fluid absorption and lung function using both cellular and animal models.****Our first goal will be to investigate, at the cellular level: 1) the signals controlling ENaC expression and the region of the ENaC promoter involved in ENaC regulation by KCh and 2) the complementary function, and relative contribution, of ENaC and KCh, on liquid absorption through ATII cells under basal conditions as well as following stimulation with -adrenergic agonists or corticosteroids. Expression of surfactant proteins will also be evaluated. Our second aim will be to pursue our in vivo studies in mice after ion channel silencing, or conversely after instillation of pharmacological compounds stimulating Na+ and K+ transport. Based on our in vitro observation showing a relationship between KCh function and ENaC expression, we will measure the level of expression of ion channels and transporters involved in alveolar clearance in situ. Finally, we will define the physiological effects of ENaC and KCh modulation on liquid clearance, surfactant production, lung function parameters as well as blood gases; in basal conditions and after stimulation with -adrenergic agonists or corticosteroids.***Our research program will allow a better understanding of the regulatory mechanisms responsible for the control of major functions of alveolar cells in lung epithelial physiology, in non-pathological conditions. Combining molecular and cellular aspects as well as an integrative model to study lung physiology in mice, our NSERC program also provides high level, multidisciplinary training to HQP in our lab.**

肺功能取决于负责表面活性剂产生和跨越离子/液体转运的肺泡上皮细胞。实际上，需要清除几乎没有液体的牙槽空间，这是气体交换所必需的。已经确定液体吸收主要由通过Na+通道ENAC的活性离子转运驱动。然而，ENAC和Na+/流体转运的复杂调节机制尚未完全理解。我们的工作还推出了另一类通道，即K+通道（KCH，KATP和KVQT1通道），该通道通过启动子活性的变化来调节ENAC表达并参与Na+/液体吸收的控制。最后，我们实施了一个综合鼠模型，以研究流体和肺功能参数的清除率。我们的初步体内数据表明ENAC和KCH之间存在关系，并控制了KCH的肺泡液清除率，表面活性剂表达和肺依从性。现在，我们提议采用我们的研究计划，以使用细胞和动物模型来阐明ENAC和KCH在控制液体吸收和肺功能中的互补作用。基础条件下的ATII细胞以及肾上腺素能激动剂或皮质类固醇的刺激。表面活性剂蛋白的表达也将进行评估。我们的第二个目的是在离子通道沉默后或在刺激刺激Na+和K+转运的药理学化合物后对小鼠进行体内研究。基于我们的体外观察结果显示了KCH功能与ENAC表达之间的关系，我们将测量与原位肺泡清除率有关的离子通道和转运蛋白的表达水平。最后，我们将定义ENAC和KCH调节对液体清除，表面活性剂产生，肺功能参数以及血液气体的生理影响；在基础条件下和用肾上腺素能激动剂或皮质类固醇刺激后。我们的NSERC计划结合了分子和细胞方面以及研究小鼠肺部生理学的综合模型，还为我们的实验室中的HQP提供了高水平的多学科培训。**