Expression of zebra fish aromatase cyp19a and cyp19b genes in response to the ligands of estrogen receptor and aryl hydrocarbon receptor
Expression of zebra fish aromatase cyp19a and cyp19b genes in response to the ligands of estrogen receptor and aryl hydrocarbon receptor
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DOI：
10.1093/toxsci/kfm003
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发表时间：
2007-04-01
影响因子：
3.8
通讯作者：
Eggen, Rik I. L.
中科院分区：
文献类型：
--
作者：
Cheshenko, Ksenia;Brion, Francois;Eggen, Rik I. L.
许多内分泌干扰物通过雌激素受体（ER）或芳香烃受体（AhR）发挥作用。为了研究雌激素受体（ER）与雌激素受体（AhR）之间的相互作用，我们研究了17 β-雌二醇（E2）和2，3，7，8-四氯二苯并-对-二恶英（TCDD）对斑马鱼cyp19a（zfcyp19a）和cyp19b（zfcyp19b）基因表达的影响。使用体内（暴露的斑马鱼幼体中的mRNA定量）和体外（细胞培养物中zfcyp19-荧光素酶报告基因对化学品和斑马鱼转录因子的反应活性）测定。除了在体外观察到的E2的轻微上调外，没有一种处理影响zfcyp19a。强烈上调zfcyp19b的E2在这两个试验中下调TCDD。这种作用可以通过添加AhR拮抗剂来挽救。TCDD对zfcyp19 b在脑中表达的抗雌激素作用也观察到蛋白水平，通过免疫组织化学评估。TCDD单独没有影响zfcyp19 b在体内的表达或启动子活性在斑马鱼AhR2和AhR核转位2b（ARNT2b）的存在下，在体外。然而，在斑马鱼ER α，AhR2和ARNT2b的存在下，TCDD导致启动子活性的轻微上调，这是由ER或AhR拮抗剂消除。突变的报告基因结构的研究表明，这两种机制的TCDD在体外的行动是独立的二恶英响应元件（DREs）预测的启动子。这项研究表明，在体内斑马鱼幼虫和在体外zfcyp19b报告基因测定雌激素化学作用的评价的有用性，提供数据预测在zfcyp19启动子的DREs的功能，并显示ER和AhR之间的串扰zfcyp19b的表达的影响。TCDD的抗雌激素作用表明，提出了进一步关注AhR配体的神经内分泌效应。
Many endocrine-disrupting chemicals act via estrogen receptor (ER) or aryl hydrocarbon receptor (AhR). To investigate the interference between ER and AhR, we studied the effects of 17 beta-estradiol (E2) and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the expression of zebra fish cyp19a (zfcyp19a) and cyp19b (zfcyp19b) genes, encoding aromatase P450, an important steroidogenic enzyme. In vivo (mRNA quantification in exposed zebra fish larvae) and in vitro (activity of zfcyp19-luciferase reporter genes in cell cultures in response to chemicals and zebra fish transcription factors) assays were used. None of the treatments affected zfcyp19a, excluding the slight upregulation by E2 observed in vitro. Strong upregulation of zfcyp19b by E2 in both assays was downregulated by TCDD. This effect could be rescued by the addition of an AhR antagonist. Antiestrogenic effect of TCDD on the zfcyp19b expression in the brain was also observed on the protein level, assessed by immunohistochemistry. TCDD alone did not affect zfcyp19b expression in vivo or promoter activity in the presence of zebra fish AhR2 and AhR nuclear translocator 2b (ARNT2b) in vitro. However, in the presence of zebra fish ER alpha, AhR2, and ARNT2b, TCDD led to a slight upregulation of promoter activity, which was eliminated by either an ER or AhR antagonist. Studies with mutated reporter gene constructs indicated that both mechanisms of TCDD action in vitro were independent of dioxin-responsive elements (DREs) predicted in the promoter. This study shows the usefulness of in vivo zebra fish larvae and in vitro zfcyp19b reporter gene assays for evaluation of estrogenic chemical actions, provides data on the functionality of DREs predicted in zfcyp19 promoters and shows the effects of cross talk between ER and AhR on zfcyp19b expression. The antiestrogenic effect of TCDD demonstrated raises further concerns about the neuroendocrine effects of AhR ligands.