Muco-ciliary differentiation of nasal epithelial cells is decreased after wound healing in vitro

Background: Epithelial damage and modi. cations of cell differentiation are frequent in airway diseases with chronic inflammation, in which transforming growth factor-beta 1 (TGF-beta 1) plays an important role. The aim of this study was to evaluate the differentiation of human nasal epithelial cells (HNEC) after wound healing and the potential effects of TGF-beta 1. Methods: Basal, mucus, and ciliated cells were characterized by cytokeratin-14, MUC5AC, and beta IV tubulin immunodetection, respectively. Their expression was evaluated in situ in nasal polyps and in an in vitro model of wound healing in primary cultures of HNEC after wound closure, under basal conditions and after TGF-b1 supplementation. Using RT-PCR, the effects of TGF-beta 1 on MUC5AC and DNAI1 genes, specifically transcribed in mucus and ciliated cells, were evaluated. Results: In situ, high TGF-beta 1 expression was associated with low MUC5AC and beta IV tubulin expression. In vitro, under basal conditions, MUC5AC expression remained stable, cytokeratin-14 expression was strong and decreased with time, while beta IV tubulin expression increased. Transforming growth factor-beta 1 supplementation downregulated MUC5AC and beta IV tubulin expression as well as MUC5AC and DNAI1 transcripts. Conclusion: After a wound, differentiation into mucus and ciliated cells was possible and partially inhibited in vitro by TGF-beta 1, a cytokine that may be involved in epithelial remodeling observed in chronic airway diseases.