IL-13 alters mucociliary differentiation and ciliary beating of human respiratory epithelial cells
Jamila Laoukili, Eric Perret, Tom Willems, Adrian Minty, Eef Parthoens, Odile Houcine, Andre Coste, Mark Jorissen, Francelyne Marano, Daniel Caput, Frédéric Tournier
Jamila Laoukili, Eric Perret, Tom Willems, Adrian Minty, Eef Parthoens, Odile Houcine, Andre Coste, Mark Jorissen, Francelyne Marano, Daniel Caput, Frédéric Tournier
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IL-13 alters mucociliary differentiation and ciliary beating of human respiratory epithelial cells

Abstract

In animal models of asthma, interleukin-13 (IL-13) induces goblet cell metaplasia, eosinophil infiltration of the bronchial mucosa, and bronchial hyperreactivity, but the basis of its effects on airway epithelia remain unknown. Lesions of the epithelial barrier, frequently observed in asthma and other chronic lung inflammatory diseases, are repaired through proliferation, migration, and differentiation of epithelial cells. An inflammatory process may then, therefore, influence epithelial regeneration. We have thus investigated the effect of IL-13 on mucociliary differentiation of human nasal epithelial cells in primary culture. We show that IL-13 alters ciliated cell differentiation and increases the proportion of secretory cells. IL-13 downregulates the actin-binding protein ezrin and other cytoskeletal components. IL-13 also impairs lateral cell contacts and interferes with the apical localization of ezrin seen in differentiated ciliated cells. In addition, an IL-4 antagonistic mutant protein (Y124D), which binds to the IL-4 receptor α subunit, a common chain of IL-4 and IL-13 receptors, inhibits IL-13’s effects. IL-13 also decreases ciliary beat frequency in a time- and dose-dependent manner. These results suggest that, in human allergic asthmatic responses, IL-13 affects both ciliated and secretory cell differentiation, leading to airway damage and obstruction.

Authors

Jamila Laoukili, Eric Perret, Tom Willems, Adrian Minty, Eef Parthoens, Odile Houcine, Andre Coste, Mark Jorissen, Francelyne Marano, Daniel Caput, Frédéric Tournier

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IL-13 affects ezrin expression and localization during mucociliary diffe...
IL-13 affects ezrin expression and localization during mucociliary differentiation. (a) 32P-labeled complex probes were obtained from epithelial cell RNAs at day 11 during MCD (+/– IL-13 from day 2) and hybridized on CLONTECH Laboratories Inc.’s Atlas cDNA arrays. CD9, a member of the tetraspanin protein family, is strongly expressed in both conditions. Merlin is not detectable in either case, while ezrin expression is downregulated by IL-13. (b) Ezrin protein expression was downregulated by IL-13 (+7, +12 days after confluence during MCD). At day 7, protein expression is identical in the two conditions. At day 12, the difference is significant. The Western blot analysis results shown are from one representative experiment, corresponding to a 30% decrease of ezrin expression in the presence of IL-13. Ten micrograms of total protein extract per lane. (c) Localization of ZO-1 and ezrin is affected by IL-13. Epithelial cells were labeled with GT335 mAb (red) in combination with either anti–ZO-1 Ab (green) or anti-ezrin Ab (green). In control conditions during MCD, anti–ZO-1 Ab reveals a continuous regular pattern, defining the subapical membrane domain (tight junctions) of each individual cell. IL-13-treatment strongly affects epithelial cell shape as observed with anti–ZO-1 staining. Anti-ezrin Ab decorates microvilli specifically located at the apical membrane of ciliated cells. In IL-13–treated spheroids, ezrin largely remains in the cytoplasm. Note the low number of ciliated cells (GT335 positive-cells) in the presence of the cytokine. Bar, 10 μm.