Induction of CAR and the nuclear localization are promoted in HepG2 hepatoma cells arrested at G_1 phase of cell cycle : Association with gene expression of UGT1A1 and Gadd45β

在细胞周期 G_1 期停滞的 HepG2 肝癌细胞中，CAR 的诱导和核定位得到促进：与 UGT1A1 和 Gadd45β 基因表达的关联

• 批准号: 16590056
• 负责人: SUGATANI Junko
• 金额: $ 2.24万
• 依托单位: University of Shizuoka
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2005
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16590056/
• 关键词: Nuclear receptor; CAR; Cell cycle; Drug-metabolizing enzyme; UGT1A1; Transcriptional cofactor; Growth factor; constitutive androstane receptor(CAR); グルクロン酸抱合酵素UGT; A1; コファクター; CYP2B6; グルクロン酸抱合酵素

UDP-glucuronosyltransferase (UGT) 1A1 glucuronidates endogenous metabolites, such as bilirubin, and exogenous substances, and plays a critical role in their detoxification and excretion. We found the phenobarbital response activity to a 290-bp distal enhancer sequence (-3499/-3210) of the human UGT1A1 gene that is activated by the constitutive androstane receptor (CAR). In addition, we show that dexamethasone at submicromolar concentrations enhances the pregnane X receptor (PXR) activator-mediated expression of the UGT1A1 gene and protein in HepG2 cells. We investigated the molecular mechanism of UGT1A1 induction by glucocorticoids at submicromolar concentrations and PXR activators and the functional cross-talk between the glucocorticoid receptor (GR) and CAR/PXR. The glucocorticoid-response element (GRE) was characterized by cotransfection experiments, site-directed mutagenesis and electrophoretic mobility shift assays. Analysis of the human UGT1A1 promoter revealed GREs at -3404/-338 … More 9 and -3251/-3236 close to the CAR/PXR response element gtNR1 (-3382/-3367). Furthermore, in an in vitro reporter gene assay, dexamethasone effectively enhanced CAR/PXR-mediated transactivation of the 290-bp distal enhancer module in HepG2 cells and CV-1 cells in the presence of exogenously expressed GR and glucocorticoid receptor-interacting protein 1 (GRIP1). Taken together, these results demonstrate a rational mechanistic basis for UGT1A1 induction by glucocorticoids and PXR activators, showing that activated GR enhances CAR/PXR-mediated UGT1A1 regulation with the transcriptional cofactor GRIP1.In this study, we demonstrate that induction of CAR and the nuclear localization are promoted in HepG2 hepatoma cells arrested at G_1 phase of cell cycle. Addition of epidermal growth factor to the cells decreased the expression of CAR. Moreover inhibition of CAR expression by RNA interference suppressed gene expression of UGT1A1 and Gadd45β. CAR may exert the effects by influencing the expression of gene involved in not only the metabolism of endogenous and exogenous substances but also the control of cell proliferation. Less

UDP-葡萄糖醛酸基转移酶 (UGT) 1A1 使内源性代谢物（如胆红素）和外源性物质进行葡萄糖醛酸化，并在其解毒和排泄中发挥关键作用。我们发现苯巴比妥对人 UGT1A1 基因的 290 bp 远端增强子序列 (-3499/-3210) 的反应活性，该序列由组成型雄甾烷受体 (CAR) 激活。此外，我们还发现亚微摩尔浓度的地塞米松可增强 HepG2 细胞中孕烷 X 受体 (PXR) 激活剂介导的 UGT1A1 基因和蛋白的表达。我们研究了亚微摩尔浓度的糖皮质激素和 PXR 激活剂诱导 UGT1A1 的分子机制，以及糖皮质激素受体 (GR) 和 CAR/PXR 之间的功能串扰。通过共转染实验、定点诱变和电泳迁移率变动分析对糖皮质激素反应元件 (GRE) 进行了表征。对人类 UGT1A1 启动子的分析显示，GRE 在 -3404/-338 … More 9 和 -3251/-3236 处接近 CAR/PXR 响应元件 gtNR1 (-3382/-3367)。此外，在体外报告基因测定中，在存在外源表达的 GR 和糖皮质激素受体相互作用蛋白 1 (GRIP1) 的情况下，地塞米松有效增强了 HepG2 细胞和 CV-1 细胞中 CAR/PXR 介导的 290 bp 远端增强子模块的反式激活。综上所述，这些结果证明了糖皮质激素和 PXR 激活剂诱导 UGT1A1 的合理机制基础，表明激活的 GR 通过转录辅因子 GRIP1 增强了 CAR/PXR 介导的 UGT1A1 调节。在这项研究中，我们证明在细胞周期 G_1 期停滞的 HepG2 肝癌细胞中促进了 CAR 的诱导和核定位。向细胞中添加表皮生长因子可降低 CAR 的表达。此外，通过RNA干扰抑制CAR表达可抑制UGT1A1和Gadd45β的基因表达。 CAR可能通过影响基因的表达来发挥作用，这些基因不仅参与内源性和外源性物质的代谢，而且还参与细胞增殖的控制。较少的

项目成果

Hepatic CYP3A expression is attenuated in obese mice fed a high-fat diet

• DOI: 10.1007/s11095-006-0071-6
• 发表时间: 2006-06-01
• 期刊: PHARMACEUTICAL RESEARCH
• 影响因子: 3.7
• 作者: Yoshinari, Kouichi;Takagi, Shunsuke;Miwa, Masao
• 通讯作者: Miwa, Masao

Transcriptional regulation of human UGT1A1 gene expression : Activated GR enhances CAR/PXR-mediated UGT1A1 regulation with GRIP1.

人类 UGT1A1 基因表达的转录调控：激活的 GR 通过 GRIP1 增强 CAR/PXR 介导的 UGT1A1 调控。

• 发表时间: 2005
• 期刊: Mol.Pharmacol 67(3)
• 作者: Tadashi Wada;et al.;Junko Sugatani et al.
• 通讯作者: Junko Sugatani et al.

Transcriptional regulation of human UGT1A1 gene expression: Activated GR enhances CAR/PXR-mediated UGT1A1 regulation with GRIP1.

人类 UGT1A1 基因表达的转录调控：激活的 GR 通过 GRIP1 增强 CAR/PXR 介导的 UGT1A1 调控。

• 发表时间: 2005
• 期刊: Mol.Pharmacol. 67(3)
• 作者: Junko Sugatani;Shinichi Nishitani;Kasurni Yamakawa;Kouichi Yoshinari;Tatsuya Sueyoshi;Masahiko Negishi;Masao Miwa;Junko Sugatani et al.
• 通讯作者: Junko Sugatani et al.

INDUCTION OF DETOXIFYING ENZYMES IN RODENT WHITE ADIPOSE TISSUE BY ARYL HYDROCARBON RECEPTOR AGONISTS AND ANTIOXIDANTS

• DOI: 10.1124/dmd.105.007286
• 发表时间: 2006-07
• 期刊: Drug Metabolism and Disposition
• 影响因子: 3.9
• 作者: K. Yoshinari;N. Okino;Takeshi Sato;J. Sugatani;M. Miwa

茶の効能と応用開発Health beneficial functions and development of tea goods

茶制品的保健功能及开发

• 发表时间: 2006
• 作者: 菅谷純子;三輪匡男;Fujimoto S. et al.;Atsushi Yamashita et al.;菅谷 純子 他
• 通讯作者: 菅谷 純子 他