Glucocorticoids decrease c-fosexpression in human nasal polyps in vivo. Issue 7 (1st July 1998)

• Record Type: Journal Article
• Authors: Baraniuk, James N; Wong, Godfrey; Ali, Mushtaq; Sabol, Marybeth; Troost, Thomas
• Is Part Of: Thorax. Volume 53:Issue 7(1998)
• Page Start: 577
• Page End: 582
• Publication Date: 1998-07-01
• Subjects: glucocorticoids -- c-fos -- AP-1 -- epithelial cells -- nasal polyps; Chest -- Diseases -- Periodicals; Thorax; Chest -- Diseases; Periodicals; Periodicals; 617.54
• DOI: 10.1136/thx.53.7.577
• Languages: English
• ISSNs: 0040-6376

Abstract

Abstract : BACKGROUND: Activated c-fos binds to jun proteins to form the activation protein 1 ( AP-1 ) transcription factor that regulates cytokine and other proinflammatory genes. c-Fos may play a key role in nasal polyp formation. Glucocorticoids may exert their anti-inflammatory effects through an interaction of glucocorticoid receptors with AP-1 that leads to mutual inactivation of both factors, and a "default" termination of AP-1 mediated gene activation. This may explain the beneficial effects of glucocorticoids in the treatment of nasal polyps. METHODS: To test this hypothesis in humans in vivo the immunohistochemical expression of c-fos -immunoreactive material ( c-fos -irm) was assessed in nasal polyps from eight steroid naive subjects, polyps from eight subjects treated with topical beclomethasone dipropionate (BDP), and normal inferior turbinate nasal mucosa (n = 6). RESULTS: mRNA for c-fos was detected in all nasal polyps and normal mucosa. In contrast, c-fos -irm was present in all steroid naive subjects but in only two of the eight subjects treated with BDP (p = 0.007, two-tailed Fisher's exact test). c-Fos -irm was expressed solely in epithelial cells and glandular structures; it was expressed in normal epithelium and glands, but the staining intensity was low. CONCLUSION: Glucocorticoids appear to modulate expression of c-fos -irm and possibly AP-1 in human airway epithelial cells in vivo.