IL-1β induction of MUC5AC gene expression is mediated by CREB and NF-κB and repressed by dexamethasone.
Chronic airway diseases are characterized by inflammation and mucus overproduction. The MUC5AC mucin gene is upregulated by the proinflammatory cytokine interleukin-1 β (IL-1β) via activation of cAMP response element-binding protein (CREB) in the NCI-H292 cancer cell line and nuclear factor-κB (NF-κB) in the HBE1 transformed cell line, with each transcription factor binding to a cognate cis site in the proximal or distal region, respectively, of the MUC5AC promoter. We utilized primary differentiated human bronchial epithelial (HBE) and A549 lung adenocarcinoma cells to further investigate the contributions of CREB and NF-κB subunits to the IL-1β-induced upregulation of MUC5AC. Data show that ligand binding of IL-1β to the IL-1β receptor is required to increase MUC5AC mRNA abundance. Chromatin immunoprecipitation analyses show direct binding of CREB to the previously identified cAMP response element site and binding of p65 and p50 subunits to a novel NF-κB site in a mucin-regulatory domain in the proximal promoter and to a previously identified NF-κB site in the distal promoter. P50 binds to both NF-κB sites at 1 h following IL-1β exposure, but is replaced at 2 h by p65 in A549 cells and by a p50/p65 heterodimer in HBE cells. Thus IL-1β activates multiple domains in the MUC5AC promoter but exhibits some cell-specific responses, highlighting the complexity of MUC5AC transcriptional regulation. Data show that dexamethasone, a glucocorticoid that transcriptionally represses MUC5AC gene expression under constitutive conditions, also represses IL-1β-mediated upregulation of MUC5AC gene expression. A further understanding of mechanisms mediating MUC5AC regulation should lead to a honing of therapeutic approaches for the treatment of mucus overproduction in inflammatory lung diseases.
Children's National, 111 Michigan Ave NW, Washington, DC 20010. mrose@childrensnational.org.
Yajun
Y
Chen
Lindsay M
LM
Garvin
Tracey J
TJ
Nickola
Alan M
AM
Watson
Anamaris M
AM
Colberg-Poley
Mary C
MC
Rose
D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D000893:Anti-Inflammatory Agents / Q000494:pharmacology; D001980:Bronchi / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D047369:Chromatin Immunoprecipitation; D017362:Cyclic AMP Response Element-Binding Protein / Q000235:genetics / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism; D003907:Dexamethasone / Q000494:pharmacology*; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D006801:Humans; D053583:Interleukin-1beta / Q000494:pharmacology*; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics* / Q000378:metabolism; D055271:Mucin 5AC / Q000235:genetics* / Q000378:metabolism; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D017472:Receptors, Interleukin-1 / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000893:Anti-Inflammatory Agents; C115163:CREB1 protein, human; D017362:Cyclic AMP Response Element-Binding Protein; D053583:Interleukin-1beta; C524678:MUC5AC protein, human; D055271:Mucin 5AC; D016328:NF-kappa B; D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D003907:Dexamethasone; D012321:DNA-Directed RNA Polymerases
IL-1β; MUC5AC mucin; chronic inflammatory lung disease; dexamethasone; gene regulation; inflammatory transcription factors