Mucin genes have different expression patterns in healthy and diseased upper airway mucosa.
BACKGROUND
Mucus hyper-secretion is a feature of several airways diseases such as chronic rhinosinusitis, asthma, and cystic fibrosis (CF). Since mucins are major components of mucus, the knowledge of their distribution and regulation in nasal tissues is likely to improve mucus hyper-secretion therapy.


OBJECTIVE
The aim of this study was to evaluate and compare mucin gene expression at epithelial and glandular levels, and to identify potential mucin expression patterns for specific upper airways pathologies.


METHODS
Immunohistochemistry for MUC1, MUC2, and MUC4-MUC8 mucins was performed on healthy nasal mucosa (NM; n=12), bilateral nasal polyps (NP; n=38), NP from CF patients (n=10), and antrochoanal (AC) polyps (n=11). MUC2, MUC4, MUC5AC, and MUC6 mRNA expression were also analysed by in situ hybridization.


RESULTS
MUC1, MUC4, and MUC5AC mucins were highly expressed in the epithelium and their expression pattern was similar in all NP types, MUC1 and MUC4 being increased and MUC5AC decreased compared with NM. MUC8 was highly detected at both epithelial and glandular levels with marked variability between groups. MUC5B was mainly detected in glands and the expression in all polyp types was higher than in NM. Moreover, MUC5B expression was higher in NP epithelia from CF patients than in bilateral NP and healthy NM. Although MUC2 expression was low, especially in AC polyps, it was detected in most samples. In NM, MUC6 and MUC7 were scarcely detected and MUC7 expression was restricted to glands.


CONCLUSIONS
These results suggest that NP have a different pattern of mucin expression than healthy NM and that CF polyps (increased MUC5B) and AC polyps (decreased MUC2) have a different mucin expression pattern than bilateral NP.
Martínez-Antón
A
A
Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Catalonia, Spain.
Debolós
C
C
Garrido
M
M
Roca-Ferrer
J
J
Barranco
C
C
Alobid
I
I
Xaubet
A
A
Picado
C
C
Mullol
J
J
D000293:Adolescent; D000328:Adult; D003550:Cystic Fibrosis / Q000235:genetics* / Q000276:immunology; D004848:Epithelium / Q000276:immunology; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D017403:In Situ Hybridization / Q000379:methods; D008297:Male; D008875:Middle Aged; D055271:Mucin 5AC; D018396:Mucin-1 / Q000235:genetics / Q000276:immunology; D055262:Mucin-2; D055264:Mucin-4; D055257:Mucin-5B; D009077:Mucins / Q000235:genetics* / Q000276:immunology; D009297:Nasal Mucosa / Q000276:immunology*; D009298:Nasal Polyps / Q000235:genetics* / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D012471:Salivary Proteins and Peptides
C524625:MUC2 protein, human; C524658:MUC4 protein, human; C524678:MUC5AC protein, human; C524578:MUC5B protein, human; C083238:MUC7 protein, human; C105059:MUC8 protein, human; D055271:Mucin 5AC; D018396:Mucin-1; D055262:Mucin-2; D055264:Mucin-4; D055257:Mucin-5B; D009077:Mucins; D012333:RNA, Messenger; D012471:Salivary Proteins and Peptides