Inhalant Corticosteroids Inhibit Hyperosmolarity-induced, and Cooling and Rewarming–induced Interleukin-8 and RANTES Production by Human Bronchial Epithelial Cells

Inhaled corticosteroids are widely used for the treatment of bronchial asthma, and a long-term treatment with inhaled corticosteroids is effective in preventing exercise-induced bronchoconstriction (EIB). We have previously shown that hyperosmolarity, and cooling and rewarming induced interleukin-8 (IL-8) expression in human bronchial epithelial cells (BEC). However, the effect of inhalant corticosteroids on hyperosmolarity-induced, and cooling and rewarming-induced IL-8 and RANTES production has not been determined. To clarify these issues, we examined the effect of inhalant corticosteroids, beclomethasone dipropionate (BDP), and budesonide (BUD) on hyperosmolarity-induced, and cooling and rewarming-induced IL-8 and RANTES production. The results showed that BDP and BUD inhibited hyperosmolarity-induced, and cooling and rewarming-induced IL-8 and RANTES production. Because our previous studies have shown that p38 mitogen-activated protein (MAP) kinase and c-Jun-NH(2)-terminal kinase (JNK) regulate hyperosmolarity-induced, and cooling and rewarming-induced IL-8 and RANTES production, we examined the effect of BDP and BUD on p38 MAP kinase and JNK activation. The results showed that BDP and BUD did not inhibit hyperosmolarity-induced and cooling-induced p38 MAP kinase and JNK activation. These results indicated that inhalant corticosteroids inhibited hyperosmolarity-, and cooling and rewarming-induced IL-8 and RANTES production; however, the mechanism of inhaled corticosteroid-mediated inhibition of hyperosmolarity-induced, and cooling and rewarming- induced cytokine production remains to be clarified.