Cystic fibrosis transmembrane conductance regulator does not affect neutrophil migration across cystic fibrosis airway epithelial monolayers

Recent studies have shown that airway inflammation dominated by neutrophils , ie, polymorphonuclear;tr cells (PMN) was observed in infants and children with cystic fibrosis (CF) even in the absence of detectable infection. To assess whether there is a CF-related anomaly of PMN migration across airway epithelial cells, we developed an. in vitro model of chemotactic migration across tight and polarized CF15 cells, a CF human nasal epithelial cell li ne, seeded on porous filters. To compare PMN migration across a pair of CF and control monolayers in the physiological direction, inverted CF15 cells were infected with increasing concentrations of recombinant adenoviruses co ntaining either the normal cystic fibrosis transmembrane conductance regula tor (CFTR) cDNA, the Delta F508 CFTR cDNA, or the beta-galactosidase gene. The number of PMN migrating in response to N-formyl-Met-Leu-Phe across inve rted CF15 monolayers expressing beta-galactosidase was similar to that seen across CF15 monolayers rescued with CFTR, whatever the proportion of cells expressing the transgene, Moreover, PMN migration across monolayers expres sing various amounts of mutated CFTR was not different from that observed a cross matched counterparts expressing normal CFTR, Finally, PMN migration i n response to adherent or Pseudomonas aeruginosa was equivalent across CF a nd corrected monolayers, The possibility that mutated CFTR may exert indire ct effects on PMN recruitment, via an abnormal production of the chemotacti c cytokine interleukin-8, was also explored. Apical and basolateral product ion of interleukin-8 by polarized CF cells expressing mutated CFTR was not different from that observed with rescued cells, either in baseline or stim ulated conditions. CF15 cells displayed a CF phenotype that could be correc ted by CFTR-containing adenoviruses, because two known CF defects, Cl- secr etion and increased P. aeruginosa adherence, were normalized after infectio n with those viruses. Thus, we conclude that the presence of a mutated CFTR does not per se lead to an exaggerated inflammatory response of CF surface epithelial cells in the absence or presence of a bacterial infection.