Niflumic Acid Reduces Histamine-Induced MUC5AC Expression in Human Conjunctival Epithelial Cells

Background/Aims: Histamine is an important inflammatory mediator in allergic conjunctivitis. The aim of the present study was to explore whether histamine induced MUC5AC production in human conjunctival epithelial cells (HCECs), and to describe the relationship between human calcium-activated chloride channel 1 (hCLCA1) activity and MUC5AC expression. Methods: HCECs were isolated from human conjunctiva and cultured at an air-liquid interface. MUC5AC and hCLCA1 mRNA expression was examined by real-time PCR after exposure of the cells to histamine. MUC5AC secretion was quantitated by ELISA. hCLCA1 protein was detected by Western blot analysis. Results: Histamine upregulated MUC5AC expression and MUC5AC secretion in a dose-dependent manner. Histamine also upregulated hCLCA1 mRNA expression in a dose-dependent manner. Preincubation of histamine receptor 1 antagonist reduced histamine-induced MUC5AC and hCLCA1 mRNA expression. Niflumic acid, a chloride channel inhibitor, reduced histamine-induced MUC5ACand hCLCA1 expression. Conclusion: Histamine-induced MUC5AC production could be decreased by niflumic acid, a calcium-activated chloride channel inhibitor.ope