TY - JOUR T1 - Regulation of <em>CYP2A5</em> Gene by the Transcription Factor Nuclear Factor (Erythroid-Derived 2)-Like 2 JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 787 LP - 794 DO - 10.1124/dmd.106.014423 VL - 35 IS - 5 AU - A'edah Abu-Bakar AU - Virpi Lämsä AU - Satu Arpiainen AU - Michael R. Moore AU - Matti A. Lang AU - Jukka Hakkola Y1 - 2007/05/01 UR - http://dmd.aspetjournals.org/content/35/5/787.abstract N2 - We have previously shown that cadmium, a metal that alters cellular redox status, induces CYP2A5 expression in nuclear factor (erythroid-derived 2)-like 2 wild-type (Nrf2+/+) mice but not in the knockout (Nrf2–/–) mice. In the present studies, the potential role of Nrf2 in cadmium-mediated regulation of Cyp2a5 gene was investigated in mouse primary hepatocytes. Cadmium chloride (CdCl2) caused a time-dependent induction of the CYP2A5 at mRNA, protein, and activity levels, with a substantial increase observed within 3 h of exposure. Immunoblotting showed cadmium-dependent nuclear accumulation of Nrf2 within 1 h of exposure. Cotransfection of mouse primary hepatocytes with Cyp2a5 promoter-luciferase reporter plasmids and Nrf2 expression plasmid resulted in a 3-fold activation of Cyp2a5 promoter-mediated transcription relative to the control. Deletion analysis of the promoter localized the Nrf2 responsive region to an area from –2656 to –2339 base pair. Computer-based sequence analysis identified two putative stress response elements (StRE) within the region at positions –2514 to –2505 and –2386 to –2377. Chromatin immunoprecipitation and electrophoretic mobility shift assays showed that interaction of the more proximal StRE with Nrf2 was stimulated by CdCl2. Finally, site-directed mutagenesis of the proximal StRE in Cyp2a5 promoter-luciferase reporter plasmids abolished Nrf2-mediated induction. Collectively, the results indicate that Nrf2 activates Cyp2a5 transcription by directly binding to the StRE in the 5′-flanking region of the gene. This acknowledges Cyp2a5 as the first phase I xenobiotic-metabolizing gene identified under the control of the StRE-Nrf2 pathway with a potential role in adaptive response to cellular stress. The American Society for Pharmacology and Experimental Therapeutics ER -