Role of disrupted ASL pH regulation in small airways in CF lung disease pathogenesis

点击翻译按钮获取中文摘要

PROJECT SUMMARY / ABSTRACT Cystic fibrosis (CF) is a common genetic disease caused by a defect in the CF transmembrane conductance regulator (CFTR). The pathogenesis of CF lung disease is unclear and controversial, at least partially due to lack of studies in an appropriate CF animal model. In addition, most studies regarding the pathogenesis rely on data from cultured human diseased large proximal airways, such as tracheal and bronchial tissue. However, pathological and clinical data suggest that the disease is initiated in small airways with a diameter <2mm. Iowa group has engineered pigs with deletion or mutation of CFTR. These pigs mimic human CF, including development of spontaneous infections and obstruction of airways with mucus and inflammatory cells. This model provides an unprecedented opportunity to investigate the pathogenesis of CF lung disease. Our objective for this study is to investigate how loss of CFTR leads to host defense defects in CF small airway epithelia and if viral vector mediated delivery of CFTR cDNA to CF small airways will rescue host defense defects. Our overall hypothesis is that AAV4 mediated delivery of CFTR will correct ASL properties and restore host defense function of small airway epithelium in CF. In Aim 1, we will use AAV4 to deliver CFTR cDNA in cultured small airway epithelial cells from CF pigs and examine ASL properties including pH and viscosity and bacterial killing abilities. In Aim 2, we will use human small airway epithelia from CF patients to test the hypothesis. In Aim 3, we will examine the cellular tropism and efficiency of AAV4 mediated gene delivery to small airway epithelium in live pigs and human lung explant. The proposed studies will lead to a better understanding of the CFTR-mediated host defense mechanisms and illustrate a potentially important yet previously underappreciated role of small airway epithelial cells in pathogenesis of CF lung disease.