title: Basic research on virus-induced asthma exacerbation: inhibition of inflammatory chemokine expression by fluticasone propionate.
abstract: BACKGROUND
  Viral infection can exacerbate asthma by inducing the accumulation of inflammatory cells in the airway. We have previously reported that double-stranded RNA (dsRNA), a viral product and ligand of the Toll-like receptor-3 (TLR3), activates the transcription factors NF-κB and IRF-3 and upregulates the expression of inflammatory chemokines in airway epithelial cells. Here, we examined the effects of the glucocorticoid fluticasone propionate (FP) on the expression of the inflammatory chemokines CCL5, CXCL8 and CXCL10.
  
  
  METHODS
  The airway epithelial cell line BEAS-2B was used for this study. Expression of CCL5, CXCL8 and CXCL10 mRNA and protein was quantified by real-time PCR and ELISA assay, respectively. To examine the association of FP with the physiology of chemokine production, we included several methods. Nuclear translocation of transcription factors was determined by performing Western blot analysis. Histone deacetylase (HDAC) activity in nuclear extracts was measured using a colorimetric assay. Stability of the chemokine mRNAs was examined in cells incubated with actinomycin D. The activities of the CCL5 promoter and the transcription factors NF-κB and IRF-3 were assessed using luciferase reporter assays.
  
  
  RESULTS
  Treatment of BEAS-2B cells with FP significantly and dose-dependently (10(-9) to 10(-6)M) inhibited dsRNA-induced expression of CCL5, CXCL8 and CXCL10 protein and mRNA, but did not affect mRNA stability. FP also significantly inhibited dsRNA-stimulated CCL5 promoter activity. However, FP had no effect on the activity of HDAC or the nuclear translocation of NF-κB and IRF-3.
  
  
  CONCLUSIONS
  FP inhibits the dsRNA-stimulated expression of inflammatory chemokines in airway epithelial cells. FP may act by inhibiting chemokine transcription through an as yet unidentified mechanism.
authors.affiliation: Department of Respiratory and Allergy Internal Medicine, Showa University School of Medicine, Tokyo, Japan. smatsuku@med.showa-u.ac.jp
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsukura
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Kurokawa
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Homma
authors.forename: Shin
authors.initials: S
authors.lastname: Watanabe
authors.forename: Shintaro
authors.initials: S
authors.lastname: Suzuki
authors.forename: Koushi
authors.initials: K
authors.lastname: Ieki
authors.forename: Hiroko
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Kyoko
authors.initials: K
authors.lastname: Notomi
authors.forename: Robert P
authors.initials: RP
authors.lastname: Schleimer
authors.forename: Mio
authors.initials: M
authors.lastname: Kawaguchi
authors.forename: Fumio
authors.initials: F
authors.lastname: Kokubu
mesh_terms: D000730:Androstadienes / Q000494:pharmacology*; D018926:Anti-Allergic Agents / Q000494:pharmacology*; D001249:Asthma / Q000235:genetics* / Q000378:metabolism / Q000821:virology; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D018946:Chemokine CCL5 / Q000235:genetics; D018925:Chemokines / Q000096:biosynthesis / Q000235:genetics*; D000068298:Fluticasone; D005786:Gene Expression Regulation / Q000187:drug effects*; D051548:Histone Acetyltransferases / Q000378:metabolism; D006801:Humans; D018836:Inflammation Mediators; D011070:Poly I-C / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D021381:Protein Transport / Q000187:drug effects; D020871:RNA Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects
chemical_list: D000730:Androstadienes; D018926:Anti-Allergic Agents; D018946:Chemokine CCL5; D018925:Chemokines; D018836:Inflammation Mediators; D012333:RNA, Messenger; D014157:Transcription Factors; D000068298:Fluticasone; D051548:Histone Acetyltransferases; D011070:Poly I-C