Release of RANTES from nasal and bronchial epithelial cells

RANTES is a chemokine with eosinophil attractant and activating activities. This study was undertaken to determine whether primary cultures of human nasal and primate bronchial epithelial cells produce RANTES and the effect of various cytokines and dexamethasone on the release of this chemokine. Nasal epithelial cells from 32 patients (HNE) and bronchial epithelial cells from 17 Macaca nemestrina monkeys (PBE) were cultured in vitro for 24 to 72 h with LPS, TNF-α, IL-1β, IFN-γ and TNF-α combined with IFN-γ and/or dexamethasone at 10 to 1000 µg/ml. Culture supernatants were assayed for RANTES by ELISA. RANTES synthesis was measured by immunoprecipitation. HNE and PBE released modest constitutive amounts of RANTES (350 to 1000 pg/ml) which did not increase with time in culture. Release of RANTES was stimulated by all activators except LPS in a time-dependent manner, with the greatest synthesis induced by the combined addition of TNF-α and IFN-γ. The combination of these activators also increased RANTES synthesis as determined by immunoprecipitation. Dexamethasone at 100 and 1000 µg/ml produced significant inhibition of stimulated RANTES release. These data indicate that normal nasal and bronchial epithelial cells release RANTES which is upregulated by various cytokines and inhibited by dexamethasone. The enhanced release is due to stimulation of both synthesis and secretion. Production of RANTES by epithelial cells could contribute to the inflammation that characterizes the respiratory tract in asthma and rhinitis and downregulation of RANTES by glucocorticoids may be one mechanism of the therapeutic effect of these agents.