Docosahexaenoic acid consumption inhibits deoxynivalenol-induced CREB/ATF1 activation and IL-6 gene transcription in mouse macrophages

J Nutr. 2006 Feb;136(2):366-72. doi: 10.1093/jn/136.2.366.

Abstract

The mycotoxin deoxynivalenol (DON) induces IgA nephropathy in mice by upregulating IL-6 expression, which is suppressed by (n-3) PUFA consumption. The purpose of this study was to test the hypothesis that consumption of the (n-3) PUFA docosahexaenoic acid (DHA) interferes with DON-induced transcriptional and post-transcriptional upregulation of IL-6 mRNA in murine macrophages. DON evoked expression of IL-6 mRNA and IL-6 heterogenous nuclear RNA (hnRNA), an indicator of ongoing IL-6 transcription, in macrophages elicited from mice fed control AIN-93G diet for 4 wk, whereas expression of both RNA species was suppressed in macrophages from mice fed AIN-93G modified to contain 30 g DHA/kg diet for the same time period. DON enhanced IL-6 mRNA stability similarly in macrophages from control and DHA-fed mice suggesting that (n-3) PUFA effects were not post-transcriptional. DON upregulated binding activity of cAMP response element binding protein (CREB) and activator protein (AP-1) to their respective consensus sequences in nuclear extracts from control-fed mice, whereas both activities were suppressed in nuclear extracts from DHA-fed mice. DON induced phosphorylation of CREB at Ser-133 and ATF1 at Ser-63 as well as intranuclear binding of phospho-CREB/ATF1 to the cis element of the IL-6 promoter in control macrophages, whereas both activities were inhibited in macrophages from DHA-fed mice. DHA consumption blocked DON-induced phosphorylation of the CREB kinase AKT. Inhibition of AKT suppressed both CREB/ATF1 phosphorylation and IL-6 transcription. These data suggest that DHA consumption suppresses DON-induced IL-6 transcription in macrophages in part by interfering with AKT-dependent phosphorylation and subsequent binding of CREB/ATF1 to the IL-6 promoter.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Activating Transcription Factor 1 / metabolism*
  • Animals
  • Cells, Cultured
  • Cyclic AMP Response Element-Binding Protein / metabolism*
  • Docosahexaenoic Acids / administration & dosage
  • Docosahexaenoic Acids / pharmacology*
  • Female
  • Gene Expression Regulation / drug effects
  • Interleukin-6 / genetics*
  • Macrophages / drug effects*
  • Macrophages / metabolism
  • Mice
  • Phospholipids / metabolism
  • Phosphorylation / drug effects
  • Proto-Oncogene Proteins c-akt / metabolism
  • RNA Stability / drug effects
  • RNA, Messenger / genetics
  • Spleen / drug effects
  • Spleen / metabolism
  • Transcription, Genetic / drug effects*
  • Transcription, Genetic / genetics
  • Trichothecenes / pharmacology*

Substances

  • Activating Transcription Factor 1
  • Creb1 protein, mouse
  • Cyclic AMP Response Element-Binding Protein
  • Interleukin-6
  • Phospholipids
  • RNA, Messenger
  • Trichothecenes
  • Docosahexaenoic Acids
  • Proto-Oncogene Proteins c-akt
  • deoxynivalenol