Glucocorticoids can affect Pseudomonas aeruginosa (ATCC 27853) internalization and intracellular calcium concentration in cystic fibrosis bronchial epithelial cells

Abstract

ABSTRACTBackground and Objective: Glucocorticoids (GCs) are anti-inflammatory agents, but their use in cystic fibrosis (CF) is controversial. In CF, the early colonization with Pseudomonas aeruginosa is mainly due to nonmucoid strains that can internalize, and induce apoptosis in the epithelial cells. Uptake of P. aeruginosa by the epithelial cells and subsequent apoptosis may prevent colonization of P. aeruginosa in CF airways. In the airway epithelia, several other biological effects, including an anti-secretory role by decreasing intracellular Ca2+ concentration have been described for this anti-inflammatory drug. However, the effects of GCs on the nonmucoid P. aeruginosa internalization and intracellular Ca2+ in CF bronchial epithelial cells have not been evaluated. Methods: We used cultured human CF bronchial airway epithelial cell (CFBE) monolayers to determine P. aeruginosa internalization, apoptosis, and intracellular Ca2+concentration in CF bronchial epithelial cells. Cells were treated with IL-6, IL-8, dexamethasone, betamethasone, or budesonide. Results: GCs in co-treatments with IL-6 reversed the effect of IL-6 by decreasing the internalization of P. aeruginosa in the CFBE cells. GCs decreased the extent of apoptosis in CFBE cells infected with internalized P. aeruginosa, and increased the intracellular Ca2+ concentration. Conclusion: These findings suggest that if internalization of P. aeruginosa reduces infection, GC therapy would increase the risk of pulmonary infection by decreasing the internalization of P. aeruginosa in CF cells, but GCs may improve airway hydration by increasing the intracellular Ca2+ concentration. Whether the benefits of GC treatment outweigh the negative effects is questionable, and further clinical studies need to be carried out.