title: The transcription factor activator protein-1 is activated and interleukin-6 production is increased in interleukin-1beta-stimulated human enterocytes.
abstract: The intestinal mucosa is an active participant in the inflammatory and metabolic response to sepsis, endotoxemia, and other critical illness. The genes for various cytokines, e.g., interleukin 6 (IL-6), are regulated by multiple transcription factors, including nuclear factor-kappa B (NF-kappaB) and activator protein-1 (AP-1). In recent studies, treatment with IL-1beta of cultured Caco-2 cells, a human intestinal epithelial cell line, resulted in increased NF-kappaB DNA binding. The effect of IL-1beta on AP-1 activity in the enterocyte and the potential role of AP-1 in enterocyte IL-6 production are not known. We treated Caco-2 cells with IL-1beta and determined AP-1 activity by electrophoretic mobility shift assay (EMSA) and IL-6 production by enzyme-linked immunosorbent assay (ELISA). Treatment of Caco-2 cells with IL-1beta resulted in a dose- and time-dependent increase in AP-1 DNA binding. Supershift analysis suggests that activated AP-1 contained c-Jun, JunD, c-Fos, FosB, and Fra1 subunits. When Caco-2 cells were transiently transfected with an AP-1 luciferase reporter plasmid, stimulation with IL-1beta resulted in increased luciferase activity, suggesting that AP-1 DNA binding increased gene activation. Additional luciferase assays were performed with a plasmid containing a wild-type or AP-1-mutated IL-6 promoter. Stimulation of these cells with IL-1beta gave rise to results supporting the role of AP-1 in the regulation of IL-6 production. Geldanamycin, which has been shown in studies to inhibit AP-1 activation, blocked IL-1beta-induced AP-1 luciferase gene activation and IL-6 production. These results suggest that the AP-1 family of transcription factors is activated by IL-1beta in human enterocytes and that AP-1 may at least in part regulate IL-6 production in these cells.
authors.affiliation: Department of Surgery, University of Cincinnati, Ohio, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Hungness
authors.forename: T A
authors.initials: TA
authors.lastname: Pritts
authors.forename: G J
authors.initials: GJ
authors.lastname: Luo
authors.forename: X
authors.initials: X
authors.lastname: Sun
authors.forename: C G
authors.initials: CG
authors.lastname: Penner
authors.forename: P O
authors.initials: PO
authors.lastname: Hasselgren
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D016227:Benzoquinones; D004247:DNA / Q000378:metabolism; D020895:Enterocytes / Q000187:drug effects / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D047029:Lactams, Macrocyclic; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D011809:Quinones / Q000494:pharmacology; D011994:Recombinant Proteins / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014407:Tumor Cells, Cultured; D000099169:Fos-Related Antigen 1
chemical_list: D001426:Bacterial Proteins; D016227:Benzoquinones; D004247:DNA; D004791:Enzyme Inhibitors; D007375:Interleukin-1; D015850:Interleukin-6; D047029:Lactams, Macrocyclic; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D011809:Quinones; D011994:Recombinant Proteins; D018808:Transcription Factor AP-1; D000099169:Fos-Related Antigen 1; C064269:FOSB protein, human; C001277:geldanamycin