Disease relevance of MUC8

• MUC8 gene expression is overexpressed in nasal polyp epithelium and is also increased by treatment with inflammatory mediators in nasal epithelial cells [1].
• A reduced expression of MUC4, MUC5AC, and MUC8 was observed in non-small cell carcinomas, regardless of their histologic subtype [2].
• Our previous studies showed that MUC8 gene expression was overexpressed in in vivo polyp epithelium in chronic sinusitis and was also increased by treatment with inflammatory mediators in an in vitro culture condition [3].
• These results indicate that MUC8 may be one of the major mucins secreted from the polyp epithelium and that it may play an important role in the pathogenesis of mucus hypersecretion in chronic sinusitis with polyps [4].

High impact information on MUC8

• The gene expression of MUCs (MUC1-MUC8) may change characteristically during malignant transformation of epithelial tissues [5].
• Our results also indicate that cAMP-response element at the -803 region of the MUC8 promoter is an important site of PGE2-induced MUC8 gene expression [1].
• In conclusion, this study gives insights into the molecular mechanism of PGE2-induced MUC8 gene expression in human airway epithelial cells [1].
• We found that pharmacologic and genetic inhibition of ERK MAPK pathway abolished IL-1 beta-induced MUC8 gene expression in normal human nasal epithelial cells [3].
• MUC5B, MUC7, and MUC8 transcripts were not detected [6].

Biological context of MUC8

• 3. Since the eight known human mucin genes map to other chromosomes, we have named this gene MUC8, in accordance with mucin gene nomenclature [7].
• MUC8 mucin gene up-regulation in chronic rhinosinusitis [8].
• Upregulation of MUC8 and downregulation of MUC5AC by inflammatory mediators in human nasal polyps and cultured nasal epithelium [4].

Anatomical context of MUC8

• However, the mechanisms of various inflammatory mediator-induced MUC8 gene expression in normal nasal epithelial cells remain unclear [1].
• Immunologic studies correlated with the results of Northern blot analysis, which revealed strong MUC8 mRNA expression in the human testis, placenta, endometrium, and cervix and weak or undetectable levels in the human epididymis, seminal vesicle, ovary, fallopian tube, and uterus [9].
• Interestingly, MUC2 and MUC8 messenger RNA (mRNA) levels were clearly upregulated in polyp epithelium compared with those of normal turbinate epithelium [10].
• Messenger RNA encoding MUC8 was detected in human sinus mucosa [8].
• MUC8 as a ciliated cell marker in human nasal epithelium [11].

Associations of MUC8 with chemical compounds

• We examined the mechanism by which prostaglandin E(2) (PGE2), an arachidonic acid metabolite, increases MUC8 gene expression levels [1].
• Dexamethasone suppressed lipopolysaccharide-induced messenger RNA levels of MUC8 [12].

Regulatory relationships of MUC8

• MUC5AC and MUC5B mRNA were mainly expressed between the 7th and the 14th day after confluence with relatively weak MUC8 and lysozyme expression [13].

Other interactions of MUC8

• In contrast, only MUC1 levels increased with no significant changes in expression of MUC5B and MUC8 in cervical tumors over normal cervical tissues [14].
• TNF-alpha, IL-1beta and a combination of both all significantly increased MUC8 mRNA levels [15].
• In addition, the expressions of mucin gene 5AC (MUCSAC) and MUC8 mRNAs were suppressed, and the expression of cornifin-alpha mRNA increased progressively as a function of differentiation in RA-deficient cultures [16].

Analytical, diagnostic and therapeutic context of MUC8

• Northern blot analysis was used to detect MUC8 messenger RNA (mRNA) in male and female reproductive tract tissues [9].
• MUC8 showed reactivity in 14 out of 15 dacryoliths analyzed by immunohistochemistry [17].
• MUC8 mRNA and protein levels were determined in NHNE cells treated with IL-1beta (10 ng/ml for 24 h) using reverse transcriptase-PCR and Western blot analysis [11].
• On Days 2, 7, 14 and 28 after confluence, ciliated cells were counted by means of cytospin slide immunostaining using H6C5 and beta-tubulin, and MUC8 mRNA levels were determined using real-time quantitative polymerase chain reaction (PCR) [11].
• The MUC5AC and MUC8 mRNA levels were analyzed by RT-PCR [18].

References