title: Dexamethasone Induces Apoptosis of Nasal Polyp-Derived Tissue Cultures Through JNK and p38 MAPK Activation.
abstract: OBJECTIVE
  Glucocorticoids, such as dexamethasone (DEX), increase apoptosis in a variety of white cells in nasal polyps and apoptosis is an important factor in the resolution of inflammation. However, the mechanism of glucocorticoids induced apoptosis in nasal polyp remains unclear. In this study the authors evaluated which pathways were engaged in apoptosis induced by DEX in an ex vivo model of nasal polyps.
  
  
  METHODS
  Nasal polyp tissues were cultured using an air-liquid interface method. Cultures were maintained in the absence or presence of DEX (10 or 100 µM) for 24 hours. To investigate the involvement of the apoptotic signaling pathways in nasal polyp, such as caspase cascades, Fas-FasL signaling pathway, mitochondrial pathway and p38 mitogen-activated protein kinase (MAPK)/JNK pathway, the authors performed reverse transcription-polymerase chain reaction and Western blotting.
  
  
  RESULTS
  The expression ratios of FasL, activated form of caspase-8, caspase-9, and caspase-3 were significantly higher in DEX-treated polyps (P<0.01). In the Bcl-2 family expression, the anti-apoptotic molecules, Bcl-2 and Bcl-XL decreased, but pro-apoptotic molecules, Bax increased, and Bid and Bad were activated. In the conventional MAPKs, JNK, and the phospho-p38 MAPK were significantly higher, but phospho-extracellular signal-regulated kinase (ERK)1/2 was significantly lower in DEX-treated polyps (P<0.01).
  
  
  CONCLUSIONS
  DEX induces apoptosis of nasal polyp via caspase cascades, Fas-FasL signaling pathway, mitochondrial pathway and p38 MAPK/JNK pathway.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Tae-Hoon
authors.initials: TH
authors.lastname: Lee
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Jung Gwon
authors.initials: JG
authors.lastname: Nam
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Ho Min
authors.initials: HM
authors.lastname: Lee
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Maryknoll Medical Center, Busan, Korea.
authors.forename: Bo-Young
authors.initials: BY
authors.lastname: Kim
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Myung-Koo
authors.initials: MK
authors.lastname: Kang
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Dong-A University College of Medicine, Busan, Korea.
authors.forename: Woo Yong
authors.initials: WY
authors.lastname: Bae
authors.affiliation: Department of Anatomy and Tumor Immunology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Dae Young
authors.initials: DY
authors.lastname: Hur
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
authors.forename: Seong Kook
authors.initials: SK
authors.lastname: Park
keywords: Apoptosis; Ex vivo; Glucocorticoids; MAPKs; Nasal polyps; Organ culture