Up-regulation of MUC5AC and MUC5B mucin genes in chronic rhinosinusitis.
BACKGROUND
Excess mucus production and hypersecretion characterize upper airway diseases. The primary mechanisms leading to mucus hypersecretion in chronic rhinosinus inflammation are not well understood. Mucus hypersecretion is commonly accompanied by goblet cell and submucosal gland cell hyperplasia. It is important to identify which mucin gene messenger RNAs (mRNAs) are expressed in the sinus mucosa.


OBJECTIVE
To investigate the expression of MUC5AC and MUC5B mRNAs and localization of these proteins in human sinus mucosa and to compare the expression of MUC5AC and MUC5B mRNAs in normal and in chronic sinus mucosa.


METHODS
Twenty chronic maxillary sinusitis mucosa samples and 20 normal maxillary sinus mucosa samples were obtained; RNAs were extracted from sinus mucosa, and semiquantitative reverse transcription-polymerase chain reaction was performed for MUC5AC and MUC5B. Localization of these proteins was sought by using immunohistochemical analysis.


RESULTS
The levels of MUC5AC and MUC5B mRNA in chronic rhinosinusitis were significantly increased compared with those in normal sinus mucosa (P =.02). In inflammed sinus mucosa, MUC5AC protein was expressed in the cytoplasm of the goblet cell in the surface epithelium, and MUC5B expression was restricted to mucous cells of the submucosal glands and to the epithelium of sinus mucosa. However, in the normal sinus mucosa, MUC5AC and MUC5B proteins were expressed at low levels in the sinus epithelium and submucosal glands, respectively.


CONCLUSIONS
These results suggest that up-regulation of MUC5AC and MUC5B, which are major components of respiratory secretion in chronic rhinosinusitis, may play important roles in the pathogenesis of sinus hypersecretion in chronic rhinosinusitis.
Kim
Dae Hoon
DH
Division of Brain Korea 21 Program for Biomedical Science, Korea University College of Medicine, Seoul, South Korea.
Chu
Ho-Suk
HS
Lee
Jin Young
JY
Hwang
Soon Jae
SJ
Lee
Sang Hag
SH
Lee
Heung-Man
HM
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D008443:Maxillary Sinus / Q000378:metabolism*; D008875:Middle Aged; D055271:Mucin 5AC; D055257:Mucin-5B; D009077:Mucins / Q000235:genetics / Q000378:metabolism*; D009297:Nasal Mucosa / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics; D012220:Rhinitis / Q000378:metabolism*; D012852:Sinusitis / Q000378:metabolism*; D015854:Up-Regulation
C524678:MUC5AC protein, human; C524578:MUC5B protein, human; D055271:Mucin 5AC; D055257:Mucin-5B; D009077:Mucins; D012333:RNA, Messenger