Normalization of raised sodium absorption and raised calcium-mediated chloride secretion by adenovirus-mediated expression of cystic fibrosis transmembrane conductance regulator in primary human cystic fibrosis airway epithelial cells

• Published in: The Journal of clinical investigation Vol. 95; no. 3; pp. 1377 - 1382
• Main Authors: Johnson, L G, Boyles, S E, Wilson, J, Boucher, R C
• Format: Journal Article
• Language: English
• Published: United States 01.03.1995
• Subjects: Adenoviridae - genetics; Biological Transport; Blotting, Western; Calcium - metabolism; Cells, Cultured; Chlorides - metabolism; Cyclic AMP - metabolism; Cystic Fibrosis - genetics; Cystic Fibrosis - metabolism; Cystic Fibrosis - therapy; Cystic Fibrosis Transmembrane Conductance Regulator; Genetic Therapy; Humans; Immunohistochemistry; Membrane Potentials; Membrane Proteins - biosynthesis; Membrane Proteins - genetics; Membrane Proteins - metabolism; Nasal Mucosa - cytology; Nasal Mucosa - physiology; Recombinant Proteins - metabolism; Sodium - metabolism
• ISSN: 0021-9738
• DOI: 10.1172/JCI117789

Cystic fibrosis airway epithelia exhibit a spectrum of ion transport properties that differ from normal, including not only defective cAMP-mediated Cl- secretion, but also increased Na+ absorption and increased Ca(2+)-mediated Cl- secretion. In the present study, we examined whether adenovirus-mediated (Ad5) transduction of CFTR can correct all of these CF ion transport abnormalities. Polarized primary cultures of human CF and normal nasal epithelial cells were infected with Ad5-CBCFTR at an moi (10(4)) which transduced virtually all cells or Ad5-CMV lacZ as a control. Consistent with previous reports, Ad5-CBCFTR, but not Ad5-CMV lacZ, corrected defective CF cAMP-mediated Cl- secretion. Basal Na+ transport rates (basal Ieq) in CF airway epithelial sheets (-78.5 +/- 9.8 microA/cm2) were reduced to levels measured in normal epithelial sheets (-30.0 +/- 2.0 microA/cm2) by Ad5-CBCFTR (-36.9 +/- 4.8 microA/cm2), but not Ad5-CMV lacZ (-65.8 +/- 6.1 microA/cm2). Surprisingly, a significant reduction in delta Ieq in response to ionomycin, a measure of Ca(2+)-mediated Cl- secretion, was observed in CFTR-expressing (corrected) CF epithelial sheets (-6.9 +/- 11.8 microA/cm2) when compared to uninfected CF epithelial sheets (-76.2 +/- 15.1 microA/cm2). Dose response effects of Ad5-CBCFTR on basal Na+ transport rates and Ca(2+)-mediated Cl- secretion suggest that the mechanism of regulation of these two ion transport functions by CFTR may be different. In conclusion, efficient transduction of CFTR corrects hyperabsorption of Na+ in primary CF airway epithelial cells and restores Ca(2+)-mediated Cl- secretion to levels observed in normal airway epithelial cells. Moreover, assessment of these ion transport abnormalities may represent important endpoints for testing the efficacy of gene therapy for cystic fibrosis.