Proceedings of The Physiological Society
University of Oxford (2011) Proc Physiol Soc 23, C93
Non-Genomic Estrogen Regulation of Airway Surface Liquid Height in Normal and Cystic Fibrosis Bronchial Epithelia
V. Saint-Criq1, J. A. Katzenellenbogen2, B. J. Harvey1
1. Molecular Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland. 2. Department of Chemistry, University of Illinois, Urbana, Illinois, United States.
Male cystic fibrosis (CF) patients survive 9 years longer than females (CF gender gap) and lung exacerbations in CF females vary during the estrous cycle. Estrogen has been reported to reduce the height of the airway surface layer (ASL) in female CF bronchial epithelium and we have previously shown an anti-secretory effect of estrogen in epithelia. Here we investigated the role of estrogen receptors and basolateral K+ channels in mediating estrogen effects on ASL height in normal (NuLi-1) and F508del CF (CuFi-1) bronchial epithelium monolayers grown on Transwell filters in an air-liquid interface. Confocal fluorescence microscopy experiments revealed that ASL height was significantly higher in the normal bronchial epithelial NuLi-1 cell line compared to the F508del CuFi-1 cells (NuLi 6.82 ± 0.33μm vs CuFi 5.58 ± 0.14μm, n=20, p<0.001). 17β-estradiol (E2, 0.1 to 10nM) reduced ASL height in both normal (25% decrease, n=5, p<0.05, ANOVA) and CF (20% decrease, n=5, p<0.05, ANOVA) cell lines after 30 min treatment. Treatment with the Cl- transport inhibitor bumetanide (10μM) or the KCNQ1 K+ channel inhibitor chromanol HMR1556 (1μM) decreased ASL height significantly in both NuLi-1 and CuFi-1 epithelia. E2 had no additive effect on ASL height in the presence of these ion transporter inhibitors. Moreover E2 decreased bumetanide-sensitive transepithelial Cl- current in normal cells (E2: 6.47 ± 2.08 μA/cm2 vs control: 9.52 ± 2.08 μA/cm2, n=3, p<0.05, paired t-test) and produced a small increase in amiloride (10μM) sensitive current in CF cells (E2: 8.75 ± 1.39 μA/cm2 vs control: 7.14 ± 1.38 μA/cm2, n=5, p=0.07, paired t-test). Treatment with the nuclear-impeded Estrogen Dendrimer Conjugate (EDC 1nM E2 equivalent concentration) produced a significant reduction in ASL height in both cell lines (4.72 ± 0.25μm in NuLi-1 and 4.86 ± 0.42μm in CuFi-1, n=5, p< 0.05, ANOVA) whereas the empty dendrimer had no effect. These results demonstrate that estrogen decreases Cl- secretion, K+ recycling and ASL height in both CF and normal bronchial epithelial cells. These rapid responses to E2 are membrane-initiated rather than via the classical nuclear receptor signal transduction pathway and target the Cl- secretory pathway and basolateral KCNQ1 K+ channels. The ion transporter inhibitor data indicate that E2 acts on ASL by inhibiting chloride secretion in normal cells and increasing sodium absorption in CF cells.
Where applicable, experiments conform with Society ethical requirements