NF-κB activation is required for C5a-induced interleukin-8 gene expression in mononuclear cells

Matthew H. Hsu, Meiying Wang, Darren D. Browning, Naofumi Mukaida, Richard D. Ye

Research output: Contribution to journalArticle

44 Scopus citations

Abstract

C5a, a potent peptide chemoattractant, stimulates interleukin-8 (IL-8) secretion from peripheral blood mononuclear cells (PBMC). Experiments were conducted to understand the mechanisms for C5a-induced IL-8 production, which was 14-fold greater than that in unstimulated cells by 2 hours. IL-8 secretion was accompanied by accumulation of IL-8 mRNA in the cytosol and by nuclear expression of a κB DNA binding activity within 30 minutes. AP-1 but not NF-IL-6 DNA binding activity was also detected in C5a-stimulated PBMC; however, its delayed expression (maximal at 4 hours) suggested a less important role in the rapid production of IL-8. The correlation between C5a- induced κB binding activity and IL-8 gene expression was examined in the RAW264.7 macrophage cells using reporter genes directed by the κB sequence from IκBα and IL-8 promoter regions. C5a-induced reporter gene expression was abolished by introducing mutations into the κB sites and by coexpression of a dominant negative IκBα construct resistant to agonist-induced phosphorylation. Pertussis toxin, which ADP-ribosylates the G(i) proteins known to couple to the C5a receptor, produced minimal inhibition of C5a- induced IL-8 expression and had little effect on C5a-induced calcium mobilization in RAW264.7 cells. These results suggest that NF-κB activation is required for C5a-induced IL-8 gene expression and that this response is mediated primarily through a pertussis toxin-insensitive pathway.

Original languageEnglish (US)
Pages (from-to)3241-3249
Number of pages9
JournalBlood
Volume93
Issue number10
DOIs
StatePublished - May 15 1999
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Immunology
  • Hematology
  • Cell Biology

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