17β-Estradiol inhibits Ca2+-dependent homeostasis of airway surface liquid volume in human cystic fibrosis airway epithelia
Ray D. Coakley, … , Steven L. Young, Robert Tarran
Ray D. Coakley, … , Steven L. Young, Robert Tarran
Published November 20, 2008
Citation Information: J Clin Invest. 2008;118(12):4025-4035. https://doi.org/10.1172/JCI33893.
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Research Article

17β-Estradiol inhibits Ca2+-dependent homeostasis of airway surface liquid volume in human cystic fibrosis airway epithelia

Abstract

Normal airways homeostatically regulate the volume of airway surface liquid (ASL) through both cAMP- and Ca2+-dependent regulation of ion and water transport. In cystic fibrosis (CF), a genetic defect causes a lack of cAMP-regulated CFTR activity, leading to diminished Cl– and water secretion from airway epithelial cells and subsequent mucus plugging, which serves as the focus for infections. Females with CF exhibit reduced survival compared with males with CF, although the mechanisms underlying this sex-related disadvantage are unknown. Despite the lack of CFTR, CF airways retain a limited capability to regulate ASL volume, as breathing-induced ATP release activates salvage purinergic pathways that raise intracellular Ca2+ concentration to stimulate an alternate pathway to Cl– secretion. We hypothesized that estrogen might affect this pathway by reducing the ability of airway epithelia to respond appropriately to nucleotides. We found that uridine triphosphate–mediated (UTP-mediated) Cl– secretion was reduced during the periovulatory estrogen maxima in both women with CF and normal, healthy women. Estrogen also inhibited Ca2+ signaling and ASL volume homeostasis in non-CF and CF airway epithelia by attenuating Ca2+ influx. This inhibition of Ca2+ signaling was prevented and even potentiated by estrogen antagonists such as tamoxifen, suggesting that antiestrogens may be beneficial in the treatment of CF lung disease because they increase Cl– secretion in the airways.

Authors

Ray D. Coakley, Hengrui Sun, Lucy A. Clunes, Julia E. Rasmussen, James R. Stackhouse, Seiko F. Okada, Ingrid Fricks, Steven L. Young, Robert Tarran

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Figure 2

E2-mediated inhibition of ASL volume homeostasis is due to changes in E2 concentrations, not ER expression levels.

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E2 inhibits ASL volume homeostasis in CF airways. (A) XZ confocal images...
(A and B) Real-time qPCR analysis in non-CF and CF airways, respectively, using primers directed to ERα and ERβ. For ERα, DNAs were obtained from 12 non-CF and 12 CF donors (for each, n = 6 males, white bars, and 6 females, black bars). For ERβ, cDNA was obtained from 6 non-CF and 6 CF donors (for each, n = 3 males, open bars, and 3 females, closed bars). In both cases, expression was normalized to peptidylprolyl isomerase A (PPIA). ERβ was not detectable by either standard PCR (not shown) or qPCR. (C and D) Mean non-CF and CF changes in ASL height, respectively, as measured by confocal microscopy following 100 μM ATP addition ± 10 nM serosal E2 to HBECs from male (white bars) and female donors (black bars). All n = 4. (E) Dose-response curve for the inhibition of ATP-mediated ASL secretion in non-CF HBECs (ΔASL height before and after 10 minutes application of 100 μM ATP) following serosal E2 addition over the range of 0.01 to 1000 nM E2 in non-CF cultures (n = 6). (F) ΔASL height before and after 10 minutes of 100 μM ATP or ADO addition. Hormones were added serosally at 10 nM prior to ATP/ADO addition at 10 μM. All n = 5–7. *P < 0.05 versus 0 nM E2. †P < 0.05 versus ATP alone. Progest., progesterone; testost, testosterone.