INDUCTION OF A CAMP-STIMULATED CHLORIDE SECRETION IN REGENERATING POORLY DIFFERENTIATED AIRWAY EPITHELIAL-CELLS BY ADENOVIRUS-MEDIATED CFTRGENE-TRANSFER

In cystic fibrosis (CF), the airway epithelium is in the process of in jury and regeneration. In the context of the CF gene therapy, we previ ously reported that regenerating poorly differentiated (PD) cells of h uman airway epithelium represent preferential cell targets for recombi nant adenoviral gene vectors. To define whether PD non-CF and CF epith elial cells possess a functional cystic fibrosis transmembrane conduct ance regulator protein (CFTR) chloride channel, we analyzed the CFTR e xpression and the regulation of chloride secretion under cyclic (c)AMP stimulation in these regenerating PD epithelial cells of non-CF and C F airway tissue. Moreover, we studied the effects of CFTR gene transfe r mediated by a replication-defective adenovirus containing the wild-t ype CFTR gene (AdCFTR) on CFTR expression and on cAMP-stimulated chlor ide secretion. Distribution of the CFTR protein was evaluated in regen erating PD airway cells by light fluorescence microscopy and scanning laser confocal microscopy. The cAMP-mediated regulation of cell membra ne chloride secretion was investigated using the whole-cell patch clam p and SPQ (6-methoxy-N-[3-sulfopropyl]quinolinium) techniques. Compare d with the absence of CFTR expression and cAMP-regulated chloride secr etion in nontransduced regenerating PD cells of either non-CF or CF or igin, transduction with AdCFTR induces a CFTR expression and a cAMP-re gulated stimulation of the cell membrane chloride secretion in the reg enerating PD cells. These results suggest that, out of the context of CF, remodeled and poorly differentiated airway epithelium may present abnormalities in ion transport. Moreover, our data suggest that, in th e context of CF gene therapy, adenoviral vectors can be efficient in c orrecting, at least partially, the chloride secretion defect in the re modeled CF airway epithelium.