title: Molecular mechanisms of repression of eotaxin expression with fluticasone propionate in airway epithelial cells.
abstract: BACKGROUND
  Glucocorticoids are known to repress the expression of CC chemokine eotaxin in airway epithelial cells. We focused our study on the molecular mechanisms of the glucocorticoid, fluticasone, in the inhibition of the expression of the eotaxin gene in the cells.
  
  
  METHODS
  The airway epithelial cell line, BEAS-2B, was stably transfected with signal transducers and activators of transcription 6 (STAT6)-expressing vector and used in the following experiments to clarify the function of STAT6. Levels of eotaxin mRNA and protein expression were determined with RT-PCR and ELISA. Mechanisms of transcriptional regulation were assessed by the electrophoretic mobility shift assay and dual luciferase assay using eotaxin promoter-luciferase reporter plasmids.
  
  
  RESULTS
  Fluticasone significantly inhibited the induction of eotaxin protein stimulated with TNF-alpha and IL-4 in the cells. Fluticasone also repressed the induction of eotaxin mRNA with these stimuli. It partially inhibited the activity of eotaxin promoter; however, it did not inhibit the nuclear translocation and binding of transcription factors, nuclear factor-kappa B (NF-kappaB) or STAT6, to the DNA derived from the proximal promoter region of the eotaxin gene. Moreover, the inhibitory effect was also conserved in the experiments using the reporter plasmid of which the putative glucocorticoid-responsive element was mutated.
  
  
  CONCLUSIONS
  Fluticasone inhibits the expression of eotaxin gene in airway epithelial cells in part through repression of the transcription. However, the mechanisms depend neither on the inhibition of transcription factors' translocation into nuclei nor the function of the putative glucocorticoid-responsive element in the promoter, indicating that other mechanisms would be related to the transcriptional repression of the eotaxin gene in airway epithelial cells.
authors.affiliation: First Department of 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: Fumio
authors.initials: F
authors.lastname: Kokubu
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Kurokawa
authors.forename: Mio
authors.initials: M
authors.lastname: Kawaguchi
authors.forename: Hideki
authors.initials: H
authors.lastname: Kuga
authors.forename: Koushi
authors.initials: K
authors.lastname: Ieki
authors.forename: Miho
authors.initials: M
authors.lastname: Odaka
authors.forename: Shintaro
authors.initials: S
authors.lastname: Suzuki
authors.forename: Shin
authors.initials: S
authors.lastname: Watanabe
authors.forename: Hiroko
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Robert P
authors.initials: RP
authors.lastname: Schleimer
authors.forename: Ulrike
authors.initials: U
authors.lastname: Schindler
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Adachi
mesh_terms: D000730:Androstadienes / Q000494:pharmacology*; D001993:Bronchodilator Agents / Q000494:pharmacology*; D002461:Cell Line, Transformed; D054413:Chemokine CCL11; D019742:Chemokines, CC / Q000096:biosynthesis*; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D000068298:Fluticasone; D006801:Humans; D008168:Lung / Q000187:drug effects / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D020545:Respiratory Mucosa / Q000187:drug effects* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050800:STAT6 Transcription Factor; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection
chemical_list: D000730:Androstadienes; D001993:Bronchodilator Agents; C515456:CCL11 protein, human; D054413:Chemokine CCL11; D019742:Chemokines, CC; D016328:NF-kappa B; D050800:STAT6 Transcription Factor; C494101:STAT6 protein, human; D015534:Trans-Activators; D000068298:Fluticasone