Effects of prostagladin E₂ on gel-forming mucin secretion in normal human nasal epithelial cells

Conclusion. The findings of this study indicate that prostaglandin E ₂ (PGE₂) induces MUC5AC gene expression and mucin secretion via the EP4 receptor in cultured normal human nasal epithelial cells. Objectives. Recently, PGE₂ was found to induce MUC5AC production via an agonist of EP2/EP4, but not EP1/EP3, in normal human airway epithelium. However, the receptor that mediates MUC5AC has not been determined. This study aimed to investigate the MUC5AC mucin gene and mucin secretion by PGE ₂ and its receptors in cultured normal human nasal epithelial cells. Methods. After treatment with PGE₂ and/or PGE₂ antagonist, gel-forming mucin mRNA expression was determined by reverse transcription-polymerase chain reaction. Total mucin and MUC5AC mucin levels were measured using an immuno-dot blotting assay. Results. PGE₂ increased only MUC5AC gene expression and MUC5AC mucin, but not expression of other gel-forming mucin genes. An EP2 receptor antagonist (AH 6809) did not suppress the PGE₂-induced MUC5AC gene expression or MUC5AC mucin. However, an EP4 receptor antagonist (AH23848) significantly suppressed the level of PGE₂-induced MUC5AC gene expression and MUC5AC mucin.