Despite advances in CF research, we still do not understand the pathogenesis of airways disease. A majormpediment to progress is lack of a CF animal model other than the mouse. Although CF mice have beenproduced, they do not develop the airway disease typically found in humans. Therefore, we developed a pigwith a targeted disruption of the CFTR gene. We chose the pig because its lungs share many anatomical,histological, biochemical, and physiologic features with human lungs. In this project, we take the uniqueopportunity to learn how loss of CFTR alters airway epithelial function in this new CF model. Severalhypotheses about the pathogenesis of CF airway disease center on defective airway epithelial electrolytetransport and abnormal airway surface liquid volume and composition. These topics are the main focus ofour application. Through collaborations with the other projects in the Program, we will discern how alteredepithelial function relates to inflammation and infection, clinical hallmarks of the disease. We concentrate onearly postnatal and young pigs because there is a critical lack of information about the human CF lung duringthis time, and yet this is precisely when loss of CFTR initiates disease.
Specific Aim 1. Does loss of CFTR alter the function of porcine airway epithelia? We will learn howlack of CFTR changes ion transport in vivo using measurements of transepithelial voltage, in vitro usingcultures of differentiated pig airway epithelia, in freshly excised airway epithelia, and in the distal airways ofthe lung. We will also learn whether apical Na+ channel and alternative CI' channel activities are increased,and how their function relates to the clinical phenotype.
Specific Aim 2. Does loss of porcine CFTR change the airway surface liquid (ASL)? Much controversysurrounds hypotheses about how lack of CFTR affects ASL. Does it reduce ASL volume? Does it changeASL ion concentrations? Is ASL pH altered? Do changes occur both in vitro and in vivo? We will answerthese questions using several independent methods. By studying both young pigs and animals after theydevelop inflammation and/or infection, we will discover how these processes change this critical liquid.
Specific Aim 3. Does loss of CFTR disrupt mucociliary transport? Lack of CFTR might cause defectivemucociliary transport (MCT) thereby initiating airway disease. Alternatively, other factors might initiate thedisease process, and then secondary defects in MCT might worsen airways disease. Current data do notallow us to discriminate between these or other hypotheses. Here, we test the hypothesis that loss of CFTRdisrupts normal MCT in vitro and in vivo.These studies will provide new insights into both CF pathogenesis and pathophysiology and therebyaccelerate the discovery of novel therapies for this lethal disease.
Showing the most recent 10 out of 110 publications
