Transforming growth factor‐β stimulates the expression of eotaxin/CC chemokine ligand 11 and its promoter activity through binding site for nuclear factor‐κB in airway smooth muscle cells |
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| Authors: | S. Matsukura M. Odaka M. Kurokawa H. Kuga T. Homma H. Takeuchi K. Notomi F. Kokubu M. Kawaguchi R. P. Schleimer M. W. Johnson M. Adachi |
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| Affiliation: | 1. First Department of Internal Medicine, Showa University School of Medicine, Tokyo, Japan;2. Department of Respiratory Internal Medicine, Showa University Fujigaoka Hospital, Kanagawa, Japan;3. Department of Respiratory Medicine, Institute of Clinical Medicine, University of Tsukuba, Ibaraki, Japan;4. Allergy‐Immunology Division, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA;5. GlaxoSmithKline R&D, Respiratory Science, Greenford, Middlesex, UK |
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| Abstract: | Background Chemokines ligands of CCR3 including eotaxin/CC chemokine ligand 11 (CCL11) may contribute to the pathogenesis of asthma. These chemokines and a growth factor (TGF‐β) may be involved in the process of airway remodelling. Objective We analysed the effects of TGF‐β on the expression of CCR3 ligands in human airway smooth muscle (HASM) cells and investigated the mechanisms. Methods HASM cells were cultured and treated with TGF‐β and Th2 cytokines IL‐4 or IL‐13. Expression of mRNA was analysed by real‐time PCR. Secretion of CCL11 into the culture medium was analysed by ELISA. Transcriptional regulation of CCL11 was analysed by luciferase assay using CCL11 promoter–luciferase reporter plasmids. Results IL‐4 or IL‐13 significantly up‐regulated the expression of mRNAs for CCL11 and CCL26. TGF‐β alone did not increase the expression of chemokine mRNAs, but enhanced the induction of only CCL11 by IL‐4 or IL‐13 among CCR3 ligands. Activity of the CCL11 promoter was stimulated by IL‐4, and this activity was enhanced by TGF‐β. Activation by IL‐4 or IL‐4 plus TGF‐β was lost by mutation of the binding site for signal transducers and activators of transcription‐6 (STAT6) in the promoter. Cooperative activation by IL‐4 and TGF‐β was inhibited by mutation of the binding site for nuclear factor‐κB (NF‐κB) in the promoter. Pretreatment with an inhibitor of NF‐κB and glucocorticoid fluticasone propionate significantly inhibited the expression of CCL11 mRNA induced by IL‐4 plus TGF‐β, indicating the importance of NF‐κB in the cooperative activation of CCL11 transcription by TGF‐β and IL‐4. Conclusion These results indicate that Th2 cytokines and TGF‐β may contribute to the pathogenesis of asthma by stimulating expression of CCL11. The transcription factors STAT6 and NF‐κB may play pivotal roles in this process. Cite this as: S. Matsukura, M. Odaka, M. Kurokawa, H. Kuga, T. Homma, H. Takeuchi, K. Notomi, F. Kokubu, M. Kawaguchi, R. P. Schleimer, M. W. Johnson and M. Adachi, Clinical & Experimental Allergy, 2010 (40) 763–771. |
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| Keywords: | airway smooth muscle cells asthma CCL11 eotaxin NF‐κ B TGF‐β |
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