Clin Exp Otorhinolaryngol. 2014 Jun;7(2):112-8. doi: 10.3342/ceo.2014.7.2.112. Epub 2014 May 21.
Dexamethasone Induces Apoptosis of Nasal Polyp-Derived Tissue Cultures Through JNK and p38 MAPK Activation.
Lee TH1, Nam JG1, Lee HM1, Kim BY2, Kang MK3, Bae WY3, Hur DY4, Park SK5.
Department of Otolaryngology-Head and Neck Surgery, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
Department of Otolaryngology-Head and Neck Surgery, Maryknoll Medical Center, Busan, Korea.
Department of Otolaryngology-Head and Neck Surgery, Dong-A University College of Medicine, Busan, Korea.
Department of Anatomy and Tumor Immunology, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
Department of Otolaryngology-Head and Neck Surgery, Busan Paik Hospital, Inje University College of Medicine, Busan, Korea.
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.
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.
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).
DEX induces apoptosis of nasal polyp via caspase cascades, Fas-FasL signaling pathway, mitochondrial pathway and p38 MAPK/JNK pathway.
Apoptosis; Ex vivo; Glucocorticoids; MAPKs; Nasal polyps; Organ culture