Differential regulation of chemokine expression by Th1 and Th2 cytokines and mechanisms of eotaxin/CCL-11 expression in human airway smooth muscle cells

M Odaka, S Matsukura, H Kuga, F Kokubu… - International archives of …, 2007 - karger.com
M Odaka, S Matsukura, H Kuga, F Kokubu, T Kasama, M Kurokawa, M Kawaguchi, K Ieki…
International archives of allergy and immunology, 2007karger.com
Background: Airway smooth muscle (ASM) cells may contribute to the pathogenesis of
asthma including airway inflammation and remodeling. We focused our study on the
regulation of chemokine expression by cytokines and analyzed the mechanisms of
eotaxin/CCL-11 expression in ASM cells. Methods: Human ASM cells were cultured in
vitroand treated with IL-4, interferon-γ (IFNγ), and tumor necrosis factor-α (TNFα). Secretion
of chemokines into the culture medium was analyzed by ELISA. Expression of eotaxin …
Background
Airway smooth muscle (ASM) cells may contribute to the pathogenesis of asthma including airway inflammation and remodeling. We focused our study on the regulation of chemokine expression by cytokines and analyzed the mechanisms of eotaxin/CCL-11 expression in ASM cells.
Methods
Human ASM cells were cultured in vitroand treated with IL-4, interferon-γ (IFNγ), and tumor necrosis factor-α (TNFα). Secretion of chemokines into the culture medium was analyzed by ELISA. Expression of eotaxin mRNA was analyzed by reverse transcription-polymerase chain reaction (RT-PCR). Binding of transcription factor signal transducer activator of transcription (STAT) 6 to the eotaxin promoter-derived DNA was analyzed by pull-down Western blot. To assess transcriptional regulation of eotaxin, cells were transfected with eotaxin promoter-luciferase reporter plasmids, and activity was determined by dual luciferase assay.
Results
The Th2 cytokine IL-4 preferentially stimulated the expression of the CC chemokine receptor (CCR) 3-ligand chemokines eotaxin, eotaxin-3, and MCP-4. The Th1 cytokine IFNγ stimulated the expression of chemokines IP-10 and RANTES. IL-4 stimulated nuclear translocation of signal transducer activator of transcription 6 (STAT6) and its binding to the eotaxin promoter region. IL-4 activated the eotaxin promoter and its activity was inhibited by mutation of the binding site for STAT6 in the promoter.
Conclusions
The Th2 cytokine IL-4 preferentially stimulated the expression of CCR3 ligand chemokines including eotaxin in ASM cells. The transcription factor STAT6 may play a pivotal role in the activation of eotaxin transcription in response to IL-4.
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