Effects of dexamethasone on mucin gene expression in cultured human nasal epithelial cells.

OBJECTIVE

To clarify 1) which mucin gene expression is influenced by glucocorticoid and 2) whether glucocorticoid influences steady-state mucin expression or mucin gene expression induced by lipopolysaccharide.

METHODS

Dissociated cells obtained from nasal polyps were cultured on a collagen gel substrate in an air-liquid interface. Dexamethasone was added to the culture medium in the steady-state and prior to the stimulation by LPS. RNAs were extracted from culture cells, and semiquantitative reverse transcriptase-polymerase chain reaction was performed for MUC2, MUC5AC, MUC5B, MUC8, and beta-actin.

RESULTS

Dexamethasone did not influence steady-state messenger RNA levels of either mucin gene. Dexamethasone suppressed lipopolysaccharide-induced messenger RNA levels of MUC8.

CONCLUSION

Glucocorticoid does not influence steady-state mucin gene expression but suppresses mucin gene expression induced by secretagogues such as lipopolysaccharide.