Regulation of airway MUC5AC expression by IL-1beta and IL-17A; the NF-kappaB paradigm.
Mucin over-production is one of the hallmarks of chronic airway diseases such as chronic obstructive pulmonary disease, asthma, and cystic fibrosis. NF-kappaB activation in airway epithelial cells has been shown to play a positive inflammatory role in chronic airway diseases; however, the role of NF-kappaB in mucin gene expression is unresolved. In this study, we have shown that the proinflammatory cytokines, IL-1beta and IL-17A, both of which utilize the NF-kappaB pathway, are potent inducers of mucin (MUC)5AC mRNA and protein synthesis by both well-differentiated primary normal human bronchial epithelial cells and the human bronchial epithelial cell line, HBE1. MUC5AC induction by these cytokines was both time- and dose-dependent and occurred at the level of promoter activation, as measured by a reporter gene assay. These effects were attenuated by the small molecule inhibitor NF-kappaB inhibitor III, as well as p65 small-interfering RNA, suggesting that the regulation of MUC5AC expression by these cytokines is via an NF-kappaB-based transcriptional mechanism. Further investigation of the promoter region identified a putative NF-kappaB binding site at position-3594/-3582 in the promoter of MUC5AC as critical for the regulation of MUC5AC expression by both IL-1beta and IL-17A. Chromatin immunoprecipitation analysis confirmed enhanced binding of the NF-kappaB subunit p50 to this region following cytokine stimulation. We conclude that an NF-kappaB-based transcriptional mechanism is involved in MUC5AC regulation by IL-1beta and IL-17A in the airway epithelium. This is the first demonstration of the participation of NF-kappaB and its specific binding site in cytokine-mediated airway MUC5AC expression.
Center of Comparative Respiratory Biology and Medicine, University of California, Davis, CA 95616, USA.
Tomoyuki
T
Fujisawa
Sharlene
S
Velichko
Philip
P
Thai
Li-Yin
LY
Hung
Fei
F
Huang
Reen
R
Wu
D001980:Bronchi / Q000187:drug effects / Q000276:immunology*; D002460:Cell Line; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005786:Gene Expression Regulation; D006801:Humans; D020381:Interleukin-17 / Q000494:pharmacology; D053583:Interleukin-1beta / Q000494:pharmacology; D055271:Mucin 5AC / Q000819:agonists / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000276:immunology / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000276:immunology; D012333:RNA, Messenger / Q000276:immunology / Q000378:metabolism; D034741:RNA, Small Interfering / Q000276:immunology / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology; D020545:Respiratory Mucosa / Q000187:drug effects / Q000276:immunology*; D051996:Transcription Factor RelA / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014162:Transfection
D004791:Enzyme Inhibitors; D020381:Interleukin-17; D053583:Interleukin-1beta; D055271:Mucin 5AC; D016328:NF-kappa B; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D051996:Transcription Factor RelA