title: Corticosteroid regulates epithelial occludin expression in nasal polyps through a MKP-1-dependent pathway.
abstract: OBJECTIVE
  To evaluate the regulatory effect of corticosteroid on occludin expression in polyp tissues of chronic rhinosinusitis with nasal polyps (CRSwNP) patients and in vitro.
  
  
  METHODS
  Twenty CRSwNP patients were enrolled and subjected to prednisone (30 mg/day for 14 days). The expression of occludin in polyp tissues was examined before and after treatment using immunohistochemical staining and quantitative reverse transcription polymerase chain reaction. Moreover, the expression of occludin in polyp-derived epithelial cells (PECs) and human bronchial epithelial cells (BECs) was examined using Western blot analysis in the presence of corticosteroid and/or MKP-1 siRNA, respectively.
  
  
  RESULTS
  mRNA and protein expression of occludin in polyp tissues was significantly upregulated after prednisone administration (p < 0.05). Corticosteroids significantly increased MKP-1 and occludin expression in cultured PECs (p < 0.05), and MKP-1 siRNA significantly decreased occludin expression in cultured BECs (p < 0.05).
  
  
  CONCLUSIONS
  Our findings suggest that corticosteroid can promote epithelial occludin expression in nasal polyps through a MKP-1-dependent pathway.
authors.affiliation: Department of Otolaryngology, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China.
authors.forename: Xi
authors.initials: X
authors.lastname: Chen
authors.forename: Xi
authors.initials: X
authors.lastname: Luo
authors.forename: Miaomiao
authors.initials: M
authors.lastname: Han
authors.forename: Xingmei
authors.initials: X
authors.lastname: Wu
authors.forename: Jiebo
authors.initials: J
authors.lastname: Guo
authors.forename: Jia
authors.initials: J
authors.lastname: Zhang
authors.forename: Haocheng
authors.initials: H
authors.lastname: Tang
authors.forename: Kejun
authors.initials: K
authors.lastname: Zuo
authors.forename: Geng
authors.initials: G
authors.lastname: Xu
authors.forename: Huabin
authors.initials: H
authors.lastname: Li
mesh_terms: D000328:Adult; D015153:Blotting, Western; D001980:Bronchi / Q000378:metabolism; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use*; D006801:Humans; D007124:Immunoenzyme Techniques; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D009298:Nasal Polyps / Q000188:drug therapy* / Q000378:metabolism*; D062793:Occludin / Q000378:metabolism*; D011241:Prednisone / Q000627:therapeutic use*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015854:Up-Regulation
chemical_list: D005938:Glucocorticoids; D062793:Occludin; D019950:Mitogen-Activated Protein Kinase 1; D011241:Prednisone