FIGURE 8.
Ferret and human ΔF508-CFTR lacks the ability to correct chloride transport and permeability in CF human and ferret polarized airway epithelia. A, polarized human CF airway epithelial cells (CuFi) grown under air liquid interface (ALI) on Millicell inserts were infected with the indicated adenoviral vectors. At 48 h post infection, the inserts were mounted in Ussing chambers, and short circuit current (ISC) measurements were made. Representative tracings are shown for the indicated samples in response to serial addition of 3-isobutyl-2-methylxanthine (IBMX, 100 μm)/forskolin (Forsk, 10 μm), Bumet (100 μm), and GlyH101 (50 μm). B, shown is quantification of the ΔISC (A). Data in this graph represent plateau value (not peak) mean ± S.E. with n = 12 Millicells for WT-CFTR and n = 10 for ΔF508-CFTR. Mock refers to uninfected controls. No significant differences between human and ferret ΔF508-CFTR values were observed by Student's t test. However, human and ferret WT-CFTR values in response to 3-isobutyl-2-methylxanthine/forskolin were significantly greater for ferret (p < 0.017); this difference and its significance was greater when peak currents were evaluated (mean data not shown). C, ferret CFTR-knock-out tracheal xenografts were infected with either ferret WT- or ΔF508-CFTR adenoviruses overnight. Transepithelial potential difference measurements were made as described under “Experimental Procedures.” Representative TEPD tracings before and after infection are shown. D, quantification of the average cAMP/forskolin and GlyH101 responses is shown. Data in this graph represent the mean ± S.E. (n = 7 measurements from 5 WT-fCFTR infected xenografts and n = 8 from 6 ΔF508-fCFTR infected xenografts). Significant differences between WT- and ΔF508-CFTR responses to both cAMP/forskolin and GlyH101 were observed by Student's t test (p < 0.0055).