REGENERATING CELLS IN HUMAN AIRWAY SURFACE EPITHELIUM REPRESENT PREFERENTIAL TARGETS FOR RECOMBINANT ADENOVIRUS

To investigate the efficiency of adenovirus-mediated gene delivery in regenerating human respiratory epithelium, we have performed infection s with an E1- and E3-deleted type 5 recombinant adenovirus containing the Escherichia coli LacZ reporter gene on different culture models of regenerating human nasal polyp surface epithelium. These models inclu ded: (i) an ex vivo organ culture of nasal polyp tissue, (ii) an expla nt outgrowth cell culture, and (iii) an in vitro wound repair model, o n dissociated cells. In ex vivo nasal polyp tissue, transduced cells w ere not detected in normal pseudostratified areas, but were found in a reas of the surface epithelium with a morphology reminiscent of regene rating airway tissue. In the explant outgrowth cell culture, adenoviru s-infected cells were preferentially detected at the periphery of the outgrowth. These transducible epithelial cells, representative of epit helial cells present in vivo during the process of surface airway epit helium regeneration, were shown to be migrating and poorly differentia ted cells, which were proliferating or not. In the in vitro wound repa ir model, the efficiency of cell transduction was much higher in cells present in the wound area than in those far from the wound area. Thes e results indicate that regenerating cells from human airway surface e pithelium represent preferential targets for transgene expression, and suggest that efficiency of CFTR gene transfer by recombinant adenovir us vectors may be higher in regenerating CF airway mucosa than in norm al tissue. However, since these cells do not show endogenous CFTR expr ession, the relevance of their preferential transduction for the funct ional correction of the ion transport defect in cystic fibrosis needs further investigations.