The transcription factor activator protein-1 is activated and interleukin-6 production is increased in interleukin-1 β-stimulated human enterocytes

Eric S. Hungness, Timothy A. Pritts, Guang Ju Luo, Xiaoyan Sun, C. Gail Penner, Per Olof Hasselgren*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

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-κB) and activator protein-1 (AP-1). In recent studies, treatment with IL-1β of cultured Caco-2 cells, a human intestinal epithelial cell line, resulted in increased NF-κB DNA binding. The effect of IL-1β 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-1β 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-1β 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-1β 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-1β 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-1β-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-1β in human enterocytes and that AP-1 may at least in part regulate IL-6 production in these cells.

Original languageEnglish (US)
Pages (from-to)386-391
Number of pages6
JournalShock
Volume14
Issue number3
DOIs
StatePublished - Sep 2000

Keywords

  • Caco-2 cells
  • Cytokine
  • Geldanamycin
  • Inflammation
  • Intestinal mucosa
  • Sepsis

ASJC Scopus subject areas

  • Emergency Medicine
  • Critical Care and Intensive Care Medicine

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