Differential regulation of eotaxin expression by IFN-γ in airway epithelial cells

• Published in: Journal of allergy and clinical immunology 2003-06, Vol.111 (6), p.1337-1344
• Main Authors: Matsukura, Satoshi, Kokubu, Fumio, Kuga, Hideki, Kawaguchi, Mio, Ieki, Koushi, Odaka, Miho, Suzuki, Shintarou, Watanabe, Shin, Takeuchi, Hiroko, Adachi, Mitsuru, Stellato, Cristiana, Schleimer, Robert P.
• Format: Article
• Language: English
• Subjects: Allergic diseases; asthma; Biological and medical sciences; Cell Line, Transformed; Chemokine CCL11; Chemokines, CC - biosynthesis; Chemokines, CC - genetics; Drug Synergism; Eotaxin; epithelial cells; Epithelial Cells - drug effects; Epithelial Cells - immunology; Gene Expression Regulation; Humans; IFN-γ; Immunopathology; Interferon-gamma - pharmacology; Medical sciences; NF-kappa B - metabolism; Promoter Regions, Genetic; Respiratory and ent allergic diseases; Respiratory Mucosa - immunology; RNA, Messenger - biosynthesis; Time Factors; Transcription, Genetic - drug effects; Tumor Necrosis Factor-alpha - antagonists & inhibitors; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 0091-6749; 1097-6825
• DOI: 10.1067/mai.2003.1513

Background: Eotaxin is a chemokine that binds with high affinity and specificity to the chemokine receptor CCR3 and plays an important role in the pathogenesis of allergic disease. Objective: We studied the regulation of eotaxin expression by the TH1 cytokine IFN-γ and analyzed its molecular mechanisms. Methods: Levels of eotaxin mRNA and protein expression in the airway epithelial cell line BEAS-2B were determined with RT-PCR and ELISA. Mechanisms of transcriptional regulation were assessed by means of electrophoretic mobility shift assays and luciferase assay with eotaxin promoter-luciferase reporter plasmids. Results: Although IFN-γ did not directly induce the expression of eotaxin protein, it increased the induction by TNF-α when these cytokines were added simultaneously. In contrast, preincubation of cells with IFN-γ for 24 hours profoundly inhibited the production induced by TNF-α. IFN-γ did not influence the TNF-α-induced binding of nuclear factor κB to a DNA probe derived from the eotaxin promoter. IFN-γ did not increase the ability of TNF-α to activate the eotaxin promoter. Studies of eotaxin mRNA levels indicate that IFN-γ combined with TNF-α increased the expression of eotaxin mRNA. When cells were preincubated with IFN-γ, there was no inhibition of the appearance of eotaxin mRNA. Conclusion: These studies demonstrate that IFN-γ enhances eotaxin expression when added in combination with TNF-α and profoundly inhibits eotaxin expression after preincubation. In both cases the available data indicate that the effect is mediated by a posttranscriptional mechanism. (J Allergy Clin Immunol 2003;111:1337-44.)