Effect of glucocorticoid on the MUC4 gene in nasal polyps.
OBJECTIVE
Among the airway mucin genes, the MUC4 gene is an important gene in its response to inflammatory diseases of the upper airway. However, the expression and regulation of the MUC4 gene in the nasal polyps remains unclear.


METHODS
The purpose of this study was to evaluate the expression of MUC4 mRNA and synthesis of mucin glycoprotein in the nasal polyps before and after treatment with a topical steroid in vivo and in vitro.


METHODS
Nasal polyps were obtained from 20 patients with chronic rhinosinusitis and were subsequently cultured. The level of MUC4 mRNA was measured by reverse-transcription polymerase chain reaction, and the amount of the MUC4 mucin glycoprotein was estimated by the enzyme-linked immunosorbent assay method.


RESULTS
The expression of MUC4 mRNA was found to be significantly higher in the nasal polyps than in the inferior turbinate (P < .05). The addition of interleukin (IL)-1 beta and lipopolysaccharide (LPS) increased the expression of MUC4 mRNA and mucin glycoprotein synthesis in cultured nasal polyp epithelial cells. Treatment with glucocorticoid inhibited the expression of MUC4 mRNA in the nasal polyps; it also inhibited the expression of IL-1 beta and LPS-induced MUC4 mRNA and mucin glycoprotein synthesis in cultured nasal polyp epithelial cells. The inhibitory effects of glucocorticoid were restored by treatment with a glucocorticoid receptor antagonist (RU-486).


CONCLUSIONS
These results suggest that the MUC4 gene is expressed in the nasal polyps and that glucocorticoid can control the expression of the MUC4 gene and mucin glycoprotein synthesis.
Bai
Chang Hoon
CH
Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Yeungnam University, Daegu, South Korea.
Song
Si-Youn
SY
Kim
Yong-Dae
YD
D000287:Administration, Topical; D014408:Biomarkers, Tumor / Q000096:biosynthesis / Q000235:genetics; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism / Q000473:pathology; D015870:Gene Expression / Q000187:drug effects*; D005938:Glucocorticoids / Q000008:administration & dosage / Q000627:therapeutic use*; D006801:Humans; D007118:Immunoassay; D055264:Mucin-4; D009077:Mucins / Q000096:biosynthesis / Q000187:drug effects / Q000235:genetics*; D009298:Nasal Polyps / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction
D014408:Biomarkers, Tumor; D005938:Glucocorticoids; C524658:MUC4 protein, human; D055264:Mucin-4; D009077:Mucins; D012333:RNA, Messenger