Delivery of CFTR by adenoviral vector to cystic fibrosis mouse lung in a model of chronic Pseudomonas aeruginosa lung infection

In cystic fibrosis (CF) there is an excessive inflammatory response to lung infections with Pseudomonas aeruginosa, which causes significant morbidity and mortality. Mice deficient in the cystic fibrosis conductance transmembrane regulator homolog (Cftr) have exaggerated production of proinflammatory cytokines in epithelial lining fluid and increased mortality in response to chronic bronchopulmonary infection with mucoid P. aeruginosa, compared with infected wild-type littermates. Whether delivery of CFTR to CF airways by an adenoviral vector (Ad2/CFTR-16) decreases cytokine production and mortality in response to chronic bronchopulmonary infection with mucoid P. aeruginosa was tested. CF mice [stock Cftrtm1Unc-TgN(FABPCFTR)#Jaw] were anesthetized with isoflurane and inoculated intranasally with either Ad2/CFTR-16, diluent (sucrose), or empty vector (Ad2/EV). Two weeks later, mice were anesthetized with 2.5% Avertin and inoculated transtracheally with P. aeruginosa-laden agarose beads (PA M57-15). The cumulative 10-day survival of mice pretreated with Ad2/CFTR-16 was significantly higher compared with mice pretreated with sucrose but not significantly higher than mice pretreated with Ad2/EV. After adjusting for differences in experiment, we found weight loss at 3 days for mice treated with Ad2/CFTR-16 to be significantly less than for the sucrose- or Ad2/EV-treated groups. However, cytokine responses were similar in all groups 3 days after infection. In conclusion, the observed survival advantage of adenoviral delivery of CFTR to the CF lung may be due either to CFTR expression or possibly to proinflammatory effects of the adenoviral vector, or both.