Cooperative activation of CCL5 expression by TLR3 and tumor necrosis factor-α or interferon-γ through nuclear factor-κB or STAT-1 in airway epithelial cells

Tetsuya Homma, Satoshi Matsukura*, Takashi Hirose, Tsukasa Ohnishi, Teruaki Kimura, Masatsugu Kurokawa, Koushi Ieki, Miho Odaka, Shintaro Suzuki, Shin Watanabe, Masayuki Sato, Mio Kawaguchi, Robert P. Schleimer, Mitsuru Adachi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

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)-κB 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-κB-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-κB, in cooperation with TLR3 signaling. IFN-γ may stabilize CCL5 mRNA up-regulated by TLR3. This mechanism may depend on STAT-1.

Original languageEnglish (US)
Pages (from-to)9-17
Number of pages9
JournalInternational archives of allergy and immunology
Volume152
Issue numberSUPPL. 1
DOIs
StatePublished - Jun 2010

Keywords

  • Airway epithelial cells
  • CCL5/RANTES
  • Nuclear factor-κB
  • STAT-1
  • TLR3

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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