title: Synthetic double-stranded RNA induces interleukin-32 in bronchial epithelial cells.
abstract: OBJECTIVE
  Interleukin (IL)-32 is a novel cytokine and is involved in the pathogenesis of various inflammatory diseases, including asthma and COPD. However, the regulatory mechanisms of IL-32 expression and its precise pathogenic role remain to be defined. Given that viral infections are known to potentially cause and exacerbate airway inflammation, in this study, we investigated the expression of IL-32 induced by synthetic double-stranded (ds) RNA, and its signaling mechanisms involved.
  
  
  METHODS
  Bronchial epithelial cells were stimulated with synthetic dsRNA poly I:C. The levels of IL-32 expression were analyzed using real-time PCR and ELISA. The involvement of transforming growth factor β-activated kinase 1 (TAK1) and a subunit of nuclear factor-κB (NF-κB), p65 was determined by western blot analyses. TAK1 inhibitor, 5Z-7-Oxozeaenol and NF-κB inhibitor, BAY 11-7082 were added to the culture to identify key signaling events leading to the expression of IL-32. Finally, the effect of short interfering RNAs (siRNAs) targeting TAK1 and p65 was investigated.
  
  
  RESULTS
  dsRNA significantly induced IL-32 gene and protein expression, concomitant with activation of TAK1 and p65. Pretreatment of 5Z-7-Oxozeaenol diminished dsRNA-induced phosphorylation of NF-κB. Both 5Z-7-Oxozeaenol and BAY 11-7082 significantly abrogated dsRNA-induced IL-32 production. Moreover, transfection of the cells with siRNAs targeting TAK1 and p65 inhibited the expression of IL-32.
  
  
  CONCLUSIONS
  The expression of IL-32 is induced by dsRNA via the TAK1-NF-κB signaling pathway in bronchial epithelial cells. IL-32 is involved in the pathogenesis of airway inflammation, and may be a novel therapeutic target for airway inflammatory diseases.
authors.affiliation: 1Department of Respiratory Medicine, Institute of Clinical Medicine, University of Tsukuba , Ibaraki , Japan.
authors.forename: Kyoko
authors.initials: K
authors.lastname: Ota
authors.forename: Mio
authors.initials: M
authors.lastname: Kawaguchi
authors.forename: Junichi
authors.initials: J
authors.lastname: Fujita
authors.forename: Fumio
authors.initials: F
authors.lastname: Kokubu
authors.forename: Shau-Ku
authors.initials: SK
authors.lastname: Huang
authors.forename: Yuko
authors.initials: Y
authors.lastname: Morishima
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsukura
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Kurokawa
authors.forename: Yukio
authors.initials: Y
authors.lastname: Ishii
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Satoh
authors.forename: Tohru
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hizawa
mesh_terms: D001980:Bronchi / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D007378:Interleukins / Q000378:metabolism*; D007783:Lactones / Q000494:pharmacology; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects / Q000502:physiology; D011014:Pneumonia / Q000378:metabolism; D012330:RNA, Double-Stranded / Q000378:metabolism*; D012118:Resorcinols / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D013450:Sulfones / Q000494:pharmacology; D051996:Transcription Factor RelA / Q000378:metabolism; D000099151:MAP Kinase Kinase Kinase 7; D015025:Zearalenone / Q000008:administration & dosage
chemical_list: D020672:I-kappa B Proteins; D007378:Interleukins; D007783:Lactones; D020930:MAP Kinase Kinase Kinases; D016328:NF-kappa B; D009570:Nitriles; D012330:RNA, Double-Stranded; D012118:Resorcinols; D013450:Sulfones; D051996:Transcription Factor RelA; D000099151:MAP Kinase Kinase Kinase 7; C434003:3-(4-methylphenylsulfonyl)-2-propenenitrile; C505734:7-oxozeanol; D015025:Zearalenone; C496971:IL32 protein, human
keywords: IL-32; NF-κB; TAK1; bronchial epithelial cell; dsRNA; p65