IL-13-induced MUC5AC production and goblet cell differentiation is steroid resistant in human airway cells
Article first published online: 20 SEP 2011
© 2011 Blackwell Publishing Ltd
Clinical & Experimental Allergy
Volume 41, Issue 12, pages 1747–1756, December 2011
How to Cite
- Issue published online: 23 NOV 2011
- Article first published online: 20 SEP 2011
- Manuscript Accepted: 25 JUL 2011
- Manuscript Revised: 20 JUL 2011
- Manuscript Received: 17 APR 2011
- goblet cells;
- normal human bronchial epithelial cells
Glucocorticosteroids (GCS) are used to treat bronchial asthma, but are not uniformly effective, especially in severe asthma. IL-13 is a T helper type 2 cytokine implicated in the pathogenesis of asthma, and IL-13 induces mucus production and goblet cell hyperplasia in airway epithelial cells. The effect of GCS on IL-13-induced mucin production is not well characterized.
The aim of this study was to evaluate the effect of dexamethasone (Dex), a potent synthetic GCS, on IL-13-induced MUC5AC mucin expression and goblet cell proliferation in differentiated normal human bronchial epithelial cells (NHBECs).
NHBECs were cultured for 14 days at an air–liquid interface with IL-13, with or without Dex. MUC5AC protein secretion and mRNA expression was determined using ELISA and quantitative real-time PCR. IL-8 production was assayed using ELISA. Histochemical analysis was performed using H&E and periodic acid-Schiff stain, and MUC5AC immunostaining.
Although Dex dose dependently inhibited IL-8 release induced by 5 ng/mL IL-13, Dex 0.001–1 μg/mL had no effect on IL-13 induced MUC5AC protein secretion or mRNA expression. Dex paradoxically increased MUC5AC induced by IL-13 at 0.5 and 1 ng/mL, but had no effect alone or with IL-13 at 0.1 ng/mL. Dex 0.001–1 μg/mL did not inhibit the differentiation of cells into goblet cells and MUC5AC-positive cells induced by IL-13.
Conclusion and Clinical Relevance
Dex at therapeutic concentrations did not inhibit the effects of IL-13 on goblet cell differentiation, characteristic of severe asthma. Paradoxically, MUC5AC production was increased with lower dose IL-13 exposure. This may lead to airway mucus obstruction commonly seen in life-threatening asthma.