Ethanol-induced expression of glutamate-cysteine ligase catalytic subunit gene is mediated by NF-kappaB

Toxicol Lett. 2009 Mar 10;185(2):110-5. doi: 10.1016/j.toxlet.2008.12.006. Epub 2008 Dec 14.

Abstract

Glutamate-cysteine ligase is a rate-limiting enzyme in the de novo synthesis of glutathione, a known scavenger of electrophiles and reactive oxygen species. Glutamate-cysteine ligase catalytic subunit (GCLC) is regulated transcriptionally by nuclear factor erythroid 2-related factor 2 (Nrf2). It has been reported that ethanol induces human GCLC production via Nrf2-mediated transactivation of the antioxidant-responsive element (ARE). Here, the luciferase reporter assay revealed the presence of an ethanol-responsive element in the human GCLC promoter; it spanned bases -1432 to -832 in hepatocytes and HepG2 cells transfected with cytochrome P450 2E1 (CYP2E1). The region lacked an ARE but had a putative nuclear factor-kappaB (NF-kappaB) element. NF-kappaB DNA-binding activity was activated in response to ethanol treatment. CYP2E1 expression was required for GCLC promoter-driven gene expression and the activation of NF-kappaB. Thus ethanol-induced GCLC transcription is mediated by not only Nrf2 but also NF-kappaB.

MeSH terms

  • Blotting, Northern
  • Catalytic Domain / genetics*
  • Cell Line, Tumor
  • Electrophoretic Mobility Shift Assay
  • Ethanol / pharmacology*
  • Gene Expression / drug effects*
  • Gene Expression / physiology
  • Glutamate-Cysteine Ligase / genetics*
  • Glutathione / metabolism
  • Humans
  • Luciferases / genetics
  • NF-kappa B / metabolism*
  • Promoter Regions, Genetic
  • Protein Binding
  • RNA / metabolism
  • Transcription, Genetic
  • Transfection

Substances

  • NF-kappa B
  • Ethanol
  • RNA
  • Luciferases
  • Glutamate-Cysteine Ligase
  • Glutathione