1. Cooperative Activation of CCL5 Expression by TLR3 and Tumor Necrosis Factor-α or Interferon-γ through Nuclear Factor-ĸB or STAT-1 in Airway Epithelial Cells
- Author
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Mitsuru Adachi, Miho Odaka, Satoshi Matsukura, Tsukasa Ohnishi, Shin Watanabe, Tetsuya Homma, Shintaro Suzuki, Takashi Hirose, Mio Kawaguchi, Koushi Ieki, Masayuki Sato, Teruaki Kimura, Robert P. Schleimer, and Masatsugu Kurokawa
- Subjects
RNA Stability ,medicine.medical_treatment ,Immunology ,Gene Expression ,Respiratory Mucosa ,Biology ,stat ,CCL5 ,Interferon-gamma ,stomatognathic system ,Genes, Reporter ,parasitic diseases ,Gene expression ,medicine ,Humans ,Immunology and Allergy ,Interferon gamma ,Phosphorylation ,RNA, Small Interfering ,Promoter Regions, Genetic ,Chemokine CCL5 ,Cell Line, Transformed ,RNA, Double-Stranded ,Original Paper ,Tumor Necrosis Factor-alpha ,NF-kappa B ,virus diseases ,Drug Synergism ,Epithelial Cells ,hemic and immune systems ,General Medicine ,NFKB1 ,Toll-Like Receptor 3 ,stomatognathic diseases ,STAT1 Transcription Factor ,Cytokine ,Cancer research ,Cytokines ,Tumor necrosis factor alpha ,Signal transduction ,Signal Transduction ,medicine.drug - Abstract
Background: CCL5/RANTES contributes to prolonged eosinophilic inflammation and asthma exacerbation after a viral infection. We studied the mechanism of CCL5 expression using viral product double-stranded RNA (dsRNA), a ligand of Toll-like receptor 3 (TLR3), and inflammatory cytokines in airway epithelial cells. Methods: The airway epithelial cell line BEAS-2B was used in our in vitro study, and the levels of CCL5 mRNA and CCL5 protein expression were determined using real-time PCR and ELISA. The activity of the CCL5 promoter region and nuclear factor (NF)-ĸB was assessed by dual luciferase assay using specific luciferase reporter plasmids. We used actinomycin D to assess the stability of mRNA. Phosphorylation of signal transducer and activator of transcription 1 (STAT-1) was analyzed by Western blot. Results: Synthetic dsRNA up-regulated the expression of CCL5 mRNA and CCL5 protein. Adding TNF-α or IFN-γ to dsRNA further increased the expression of CCL5. The combination of TNF-α and dsRNA cooperatively activated the CCL5 promoter region and the NF-ĸB-specific reporter. IFN-γ did not activate these reporters. However, it increased the stability of CCL5 mRNA induced by dsRNA. IFN-γ phosphorylated STAT-1, but dsRNA did not. The effects of IFN-γ were not evident in the cells transfected with short interfering RNA for STAT-1. Conclusions: Cross-talk between TLR3 signaling and inflammatory cytokines regulates the expression of CCL5 in airway epithelial cells. In this mechanism, TNF-α may activate NF-ĸB, in cooperation with TLR3 signaling. IFN-γ may stabilize CCL5 mRNA up-regulated by TLR3. This mechanism may depend on STAT-1.
- Published
- 2010
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