Journal article
Redox-sensitive interaction between KIAA0132 and Nrf2 mediates indomethacin-induced expression of γ-glutamylcysteine synthetase
Free radical biology & medicine, Vol.32(7), pp.650-662
2002
DOI: 10.1016/S0891-5849(02)00755-4
PMID: 11909699
Abstract
Exposure of HepG2 cells to nonsteroidal anti-inflammatory drugs (i.e., indomethacin and ibuprofen; NSAIDs) as well as resveratrol, caused increased expression of the mRNAs coding for the catalytic (Gclc) and modifier (Gclm) subunits of the glutathione synthetic enzyme, γ-glutamylcysteine synthetase. In addition, indomethacin exposure increased intracellular glutathione content as well as inhibited glutathione depletion and cytotoxicity caused by diethyl maleate. Indomethacin-induced increases in the expression of γ-glutamylcysteine synthetase mRNA were preceded by increases in steady state levels of intracellular pro-oxidants and glutathione disulfide accumulation. Simultaneous incubation with the thiol antioxidant N-acetylcysteine (NAC) inhibited indomethacin-mediated increases in GCLC mRNA, suggesting that increases in GCLC message were triggered by changes in intracellular oxidation/reduction (redox) reactions. Indirect immunofluorescence using intact cells demonstrated that indomethacin induced the nuclear translocation of Nrf2, a transcription factor believed to regulate GCLC expression. Immunoprecipitation studies showed that indomethacin treatment also inhibited Nrf2 tethering to KIAA0132 (the human homolog of Keap1 accession #D50922), which is believed to be a negative regulator of Nrf2. Consistent with this idea, over-expression of Nrf2 increased GCLC reporter gene expression and over-expression of KIAA0132 inhibited GCLC reporter gene activity as well as inhibited indomethacin-induced increases in the expression of GCLC. Finally, simultaneous treatment with NAC inhibited both indomethacin-induced release of Nrf2 from KIAA0132 and indomethacin-induced nuclear translocation of Nrf2. These results demonstrate that NSAIDs and resveratrol cause increases in the expression of γ-glutamylcysteine synthetase mRNA and identify these agents as being capable of stimulating glutathione metabolism. These results also support the hypothesis that indomethacin-induced transcriptional activation of GCLC involves the redox-dependent release of KIAA0132 from Nrf2 followed by the nuclear translocation of Nrf2.
Details
- Title: Subtitle
- Redox-sensitive interaction between KIAA0132 and Nrf2 mediates indomethacin-induced expression of γ-glutamylcysteine synthetase
- Creators
- Konjeti R Sekhar - Vanderbilt UniversityDouglas R Spitz - University of IowaStephanie Harris - Vanderbilt UniversityTrung T Nguyen - Vanderbilt UniversityMichael J Meredith - Oregon Health & Science UniversityJeffrey T Holt - Vanderbilt UniversityDavid Gius - Washington University in St. LouisLawrence J Marnett - Vanderbilt UniversityMarshall L Summar - Vanderbilt UniversityMichael L Freeman - Vanderbilt University
- Resource Type
- Journal article
- Publication Details
- Free radical biology & medicine, Vol.32(7), pp.650-662
- Publisher
- Elsevier Inc
- DOI
- 10.1016/S0891-5849(02)00755-4
- PMID
- 11909699
- ISSN
- 0891-5849
- eISSN
- 1873-4596
- Language
- English
- Date published
- 2002
- Academic Unit
- Pathology; Radiation Oncology; Fraternal Order of Eagles Diabetes Research Center
- Record Identifier
- 9984312988502771
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