Physiology and Molecular Biology of Lung Water Transport

描述（由申请人提供）：本提案的中心重点是确定健康和疾病中肺和气道中水/液体运输的基本机制，并确定药物开发的新靶点。水通道蛋白（AQPs）是在肺微血管（AQP1）、气道（AQP3和AQP4）、肺泡上皮（AQP5）和粘膜下腺上皮（AQP5）中表达的水转运蛋白。在初始奖励期，生成缺乏四种主要肺水通道的小鼠，并用于研究水通道蛋白在肺泡、大气道和气道粘膜下腺的液体运输中的作用。一个重要的发现-气道粘膜下腺aqp5依赖性液体分泌-将在Aim 1中随访。新型水通道蛋白选择性抑制剂和模型系统将用于验证人体粘膜下腺的液体分泌受AQP5表达和功能调节的假设。目的2将利用抑制剂、小鼠模型和人体组织，重点探讨水通道蛋白在肺生理学其他方面的作用。在临床相关疾病/损伤后，肺/气道水通道蛋白促进液体从空气和肺实质中清除的假设将得到验证。在Aim 3中，新的肺切片、细胞培养和荧光方法将用于定义远端气道中水和盐的运输机制，远端气道是一个重要但研究不足的上皮。验证远端气道液体吸收需要AQP4和CFTR的假设，确定远端气道上皮在肺液体清除中的作用。总之，这些实验将为水通道蛋白在肺部生理和疾病中的作用提供明确的信息。我们的研究项目的一个独特优势是引入了新的方法来研究体内和新鲜收获的组织中的肺生理，并开发了敏锐的生物物理工具（荧光探针，显微镜方法）和用于水和离子运输研究的抑制剂。

DESCRIPTION (provided by applicant): The central focus of this proposal is to define the basic mechanisms of water/fluid transport in the lung and airways in health and disease, and to identify new targets for drug development. Aquaporins (AQPs) are water-transporting proteins expressed in lung microvasculature (AQP1), airways (AQP3 and AQP4), alveolar epithelium (AQP5) and submucosal gland epithelium (AQP5). In the initial award period, mice lacking each of the four major lung aquaporin water channels were generated and used to study the role of aquaporins in fluid transport in alveoli, large airways, and airway submucosal glands. An important finding - AQP5-dependent fluid secretion in airway submucosal glands - will be followed up in Aim 1. Novel aquaporin-selective inhibitors and model systems will be used to test the hypothesis that fluid secretion in human submucosal glands is regulated by AQP5 expression and function. Aim 2 will critically address the role of aquaporins in other aspects of lung physiology using inhibitors, mouse models, and human tissues. The hypothesis will be tested that lung/airway aquaporins facilitate fluid removal from the airspaces and lung parenchyma following clinically relevant disease/injury. In Aim 3, novel lung slice, cell culture and fluorescence methods will be used to define water and salt transporting mechanisms in distal airways, an important but under-studied epithelium. The hypothesis that AQP4 and CFTR are required for distal airway fluid absorption will be tested, and the role of the distal airway epithelium is lung fluid clearance will be determined. Together, these experiments will provide definitive information on the role of aquaporins in lung physiology and disease. A unique strength of our research program has been the introduction of new approaches to study lung physiology in vivo and in freshly harvested tissues, and the development of incisive biophysical tools (fluorescent probes, microscopy methods) and inhibitors for water and ion transport studies.