Up-regulation of human CYP2J2 in HepG2 cells by butylated hydroxyanisole is mediated by c-Jun and Nrf2.
Cytochrome P450 2J2 oxidizes arachidonic acid to a series of epoxyeicosatrienoic acid (EET) isomers in human tissues. EETs regulate numerous homeostatic processes, including cytoprotective and proliferative responses against injurious stresses. There is little information currently available on the factors that regulate CYP2J2, but strategies to activate expression could use the beneficial effects of EETs in cells. The basic leucine zipper (bZIP) transcription factor c-Jun has been shown previously to maintain CYP2J2 expression in human HepG2 cells; c-Jun forms transcriptionally active dimers with the antioxidant-inducible bZIP factor Nrf2. In the present study, we tested the hypothesis that CYP2J2 expression may be activated in cells by c-Jun/Nrf2 heterodimers. Treatment of HepG2 cells with butylated hydroxyanisole elicited concentration- and time-dependent activation of CYP2J2 expression, as well as the bZIP factors Nrf2 and c-Jun; chromatin immunoprecipitation assays revealed a pronounced increase in binding of these bZIP factors to the CYP2J2 5'-flank. Transient transfection analysis using deletion constructs and gel-shift assays were consistent with a role for the -105/-88 region of CYP2J2 in c-Jun/Nrf2 responsiveness. Using a series of mutant expression plasmids, we identified c-Jun as the critical partner in CYP2J2 transactivation. Coimmunoprecipitation experiments confirmed the importance of the leucine zipper region of Nrf2 in the enhancement of c-Jun-dependent transactivation of CYP2J2. Agents that activate CYP2J2 expression may offer a new approach to using the beneficial effects of EETs in cells.
Lee
Andy C
AC
Pharmacogenomics and Drug Development Group, Faculty of Pharmacy, University of Sydney, NSW 2006, Australia.
Murray
Michael
M
D000975:Antioxidants / Q000494:pharmacology*; D001483:Base Sequence; D002083:Butylated Hydroxyanisole / Q000494:pharmacology*; D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D000090762:Cytochrome P-450 CYP2J2; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics / Q000378:metabolism*; D017931:DNA Primers; D024202:Electrophoretic Mobility Shift Assay; D006801:Humans; D051267:NF-E2-Related Factor 2 / Q000502:physiology*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D016755:Proto-Oncogene Proteins c-jun / Q000502:physiology*; D015533:Transcriptional Activation; D015854:Up-Regulation / Q000187:drug effects*
D000975:Antioxidants; C000717350:CYP2J2 protein, human; D017931:DNA Primers; D051267:NF-E2-Related Factor 2; C495635:NFE2L2 protein, human; D016755:Proto-Oncogene Proteins c-jun; D002083:Butylated Hydroxyanisole; D003577:Cytochrome P-450 Enzyme System; D000090762:Cytochrome P-450 CYP2J2