Human CYP1A1GFP expression in transgenic mice serves as a biomarker for environmental toxicant exposure
Human CYP1A1GFP expression in transgenic mice serves as a biomarker for environmental toxicant exposure
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DOI：
10.1093/toxsci/kfl144
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发表时间：
2007-01-01
影响因子：
3.8
通讯作者：
Tukey, Robert H.
中科院分区：
文献类型：
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作者：
Operana, Theresa N.;Nguyen, Nghia;Tukey, Robert H.
人CYP 1A 1基因受芳烃受体（AhR）调节，已知CYP 1A 1的诱导在异生物质代谢中起重要作用。为了检查体内人CYP 1A 1的调节，我们创建了表达由与GFP报告基因融合的完整人CYP 1A 1基因（15 kb）组成的嵌合基因的转基因小鼠品系（Tg-CYP 1A 1（GFP））。通过荧光和Western印迹分析确定，用2，3，7，8-四氯二苯并-对-二恶英（TCDD）或苯并[a]芘（B[a]P）单次腹膜内剂量处理Tg-CYP 1A 1（GFP）小鼠导致肝脏和肺中的CYP 1A 1（GFP）诱导。肝脏中诱导荧光的定位也证明了培养的肝细胞在检查AhR激动剂诱导CYP 1A 1（GFP）的作用中的有用性。B[a]P的其他给药途径，例如以100 mg/kg剂量经口暴露3天，导致肝脏和肺中CYP 1A 1（GFP）的诱导降低。在肝脏中，CYP 1A 1（GFP）的表达是经口暴露的敏感标志物，而小鼠CYP 1A 1在这些剂量下未被诱导。虽然B[a]P在胃肠道中的首过代谢降低了AhR在肝脏中诱导CYP 1A 1（GFP）的潜力，但通过在表达人UGT 1基因座的转基因小鼠中诱导人UGT 1A蛋白证明，足够的浓度可到达肝循环。在体内识别荧光标记的CYP 1A 1的能力提供了基因反应的灵敏测量，并将暴露于潜在的环境毒物和AhR的激活联系起来。
The human CYP1A1 gene is regulated by the aryl hydrocarbon receptor (AhR), and induction of CYP1A1 is known to play an important role in xenobiotic metabolism. To examine the regulation of human CYP1A1 in vivo, we created a transgenic mouse strain (Tg-CYP1A1(GFP)) expressing a chimeric gene consisting of the entire human CYP1A1 gene (15 kb) fused with a GFP reporter gene. The treatment of Tg-CYP1A1(GFP) mice with a single intraperitoneal dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) or benzo[a]pyrene (B[a]P) led to the induction of CYP1A1(GFP) in both the liver and the lung as determined by fluorescence and Western blot analysis. The localization of induced fluorescence in liver also demonstrated the usefulness of cultured hepatocytes in examining the actions of AhR agonists toward induction of CYP1A1(GFP). Other routes of B[a]P administration, such as by oral exposure at 100 mg/kg for 3 days, led to reduced induction of CYP1A1(GFP) in liver and lung. In liver, expression of CYP1A1(GFP) was a sensitive marker for oral exposure, while mouse CYP1A1 was not induced at these doses. While first pass metabolism of B[a]P in the gastrointestinal tract reduces the potential of the AhR to induce CYP1A1(GFP) in the liver, adequate concentrations reach the hepatic circulation as demonstrated by induction of human UGT1A proteins in transgenic mice that express the human UGT1 locus. The capability to identify fluorescently labeled CYP1A1 in vivo provides a sensitive measurement of gene response and links exposure to potential environmental toxicants and activation of the AhR.