Lipopolysaccharide-induced expression of NAD(P)H:quinone oxidoreductase 1 and heme oxygenase-1 protects against excessive inflammatory responses in human monocytes

J Immunol. 2008 Nov 15;181(10):6730-7. doi: 10.4049/jimmunol.181.10.6730.

Abstract

Monocytes play a central role in the immunopathological effects of sepsis. This role is mediated by production of the cytokines TNF-alpha and IL-1beta. The transcription factor NF-E2-related factor 2 (Nrf2) regulates innate immune responses in various experimental disease models. Presently, the role of Nrf2-regulated genes in LPS-treated human monocytes is not well defined. Herein we show that Nrf2 mediates a significant regulation of LPS-induced inflammatory responses. Analysis of Nrf2-regulated gene expression in human monocytes showed that LPS induced the expression of the phase II detoxification gene NAD(P)H:quinone oxidoreductase 1 (NQO1). Furthermore, NQO1 mRNA or protein expression in response to LPS was regulated by Nrf2. Silencing Nrf2 expression in human monocytes inhibited LPS-induced NQO1 expression; however, in contrast, it significantly increased TNF and IL-1beta production. Silencing expression of NQO1 alone, or in combination with heme oxygenase-1 (HO-1) silencing, markedly increased LPS-induced TNF and IL-1beta expression. Additionally, overexpression of NQO1 and/or HO-1 inhibited LPS-induced TNF and IL-1beta expression. These results show for the first time that LPS induces NQO1 and HO-1 expression in human monocytes via Nrf2 to modulate their inflammatory responsiveness, thus providing novel potential therapeutic strategies for the treatment of sepsis.

MeSH terms

  • Cell Line
  • Gene Expression
  • Gene Expression Regulation / immunology*
  • Gene Silencing
  • Heme Oxygenase-1 / biosynthesis*
  • Heme Oxygenase-1 / genetics
  • Heme Oxygenase-1 / immunology
  • Humans
  • Inflammation / genetics
  • Inflammation / immunology*
  • Interleukin-1beta / biosynthesis
  • Lipopolysaccharides / immunology*
  • Monocytes / immunology*
  • NAD(P)H Dehydrogenase (Quinone) / biosynthesis*
  • NAD(P)H Dehydrogenase (Quinone) / genetics
  • NAD(P)H Dehydrogenase (Quinone) / immunology
  • NF-E2-Related Factor 2 / genetics
  • NF-E2-Related Factor 2 / immunology
  • RNA, Messenger / analysis
  • Reactive Oxygen Species / immunology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sepsis / genetics
  • Sepsis / immunology
  • Tumor Necrosis Factor-alpha / biosynthesis

Substances

  • Interleukin-1beta
  • Lipopolysaccharides
  • NF-E2-Related Factor 2
  • NFE2L2 protein, human
  • RNA, Messenger
  • Reactive Oxygen Species
  • Tumor Necrosis Factor-alpha
  • HMOX1 protein, human
  • Heme Oxygenase-1
  • NAD(P)H Dehydrogenase (Quinone)
  • NQO1 protein, human