Ethanol-induced expression of glutamate-cysteine ligase catalytic subunit gene is mediated by NF-kappaB.
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.
Kimura
Tomoki
T
Department of Toxicology, Faculty of Pharmaceutical Sciences, Setsunan University, 45-1 Nagaotoge-cho, Hirakata, Osaka 573-0101, Japan. tomoki@pharm.setsunan.ac.jp
Kawasaki
Yukiko
Y
Okumura
Fumika
F
Sone
Tomomichi
T
Natsuki
Reiko
R
Isobe
Masakazu
M
D015152:Blotting, Northern; D020134:Catalytic Domain / Q000235:genetics*; D045744:Cell Line, Tumor; D024202:Electrophoretic Mobility Shift Assay; D000431:Ethanol / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects* / Q000502:physiology; D005721:Glutamate-Cysteine Ligase / Q000235:genetics*; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D008156:Luciferases / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012313:RNA / Q000378:metabolism; D014158:Transcription, Genetic; D014162:Transfection
D016328:NF-kappa B; D000431:Ethanol; D012313:RNA; D008156:Luciferases; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione