Expression of the chemokine RANTES by a human bronchial epithelial cell line: Modulation by cytokines and glucocorticoids

The chemokine RANTES is a potent chemoattractant for eosinophils, lymphocytes, and monocytes, and has been detected recently in the epithelium of human airways mucosa. We have studied, therefore, the expression of RANTES mRNA and protein in the human bronchial epithelial cell line BEAS-2B. Using Northern blot analysis, RANTES mRNA was not detectable in unstimulated BEAS 2B cells. Incubation of cells with TNF-α or IFN-γ induced the expression of RANTES mRNA and protein within 16 h. The combination of TNF-α and IFN-γ displayed a marked synergism in inducing RANTES expression. Pretreatment of cells with the glucocorticoid budesonide (10^-10-10^-7 M) for 24 h inhibited expression of RANTES mRNA and protein stimulated by either TNF-α or TNF-α plus IFN-γ in a concentration and time dependent manner. Nonglucocorticoid steroids did not inhibit RANTES mRNA expression. Production of RANTES by epithelium could contribute to the mechanism of selective cellular recruitment occurring in the airways during inflammation, thus playing a relevant role in the pathogenesis of diseases such as asthma, rhinitis, and polyposis. The down regulation of RANTES production by glucocorticoids in epithelial cells may contribute to the efficacy of these compounds in reducing cellular infiltration and, ultimately, to their anti- inflammatory properties.