Extract of Ginkgo biloba induces phase 2 genes through Keap1-Nrf2-ARE signaling pathway
Extract of Ginkgo biloba induces phase 2 genes through Keap1-Nrf2-ARE signaling pathway
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DOI：
10.1016/j.lfs.2007.01.034
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发表时间：
2007-04-03
期刊：
影响因子：
6.1
通讯作者：
Park, B. Kevin
中科院分区：
文献类型：
--
作者：
Liu, Xiao-Ping;Goldring, Christopher E. P.;Park, B. Kevin
银杏叶标准提取物 (EGb) 已被证明在细胞系和动物中具有显着的抗氧化活性。然而，这种效应背后的分子机制尚不完全清楚。第 2 相酶通过减少亲电子试剂和活性氧 (ROS) 在抗氧化系统中发挥重要作用。我们通过实时 PCR 证明 EGb 诱导典型的 2 相基因：谷氨酸半胱氨酸连接酶催化亚基 (GCLC) 和谷胱甘肽-S-转移酶亚基-PI (GST-P1)。为了研究这种诱导的分子机制，我们使用醌氧化还原酶 1 (NQO1) - 抗氧化反应元件 (ARE) 报告基因检测，发现 EGb 激活野生型的活性，但不激活 ARE 突变型的活性。这表明EGb通过ARE诱导这些基因，ARE是一个位于几乎所有2期基因启动子区域的顺式作用基序。由于核因子红细胞2相关因子2（Nrf2）与ARE结合增强2相基因的表达，我们检测了细胞核中Nrf2的含量，发现EGb刺激Nrf2的积累。在对细胞质中Nrf2抑制蛋白Kelch-like ECH相关蛋白1（Keap1）的进一步测试中，我们发现Keap1含量被EGb抑制，然后更多的Nrf2被释放并转入细胞核。由此，首次证明EGb通过Keap1-Nrf2-ARE信号通路诱导2相基因，这是EGb的抗氧化机制（或部分）。 (c) 2007 Elsevier Inc. 保留所有权利。
The standard extract of Ginkgo biloba (EGb) has been demonstrated to possess remarkable antioxidant activity in both cell lines and animals. However, the molecular mechanism underlying this effect is not fully understood. Phase 2 enzymes play important roles in the antioxidant system by reducing electrophiles and reactive oxygen species (ROS). We demonstrated that EGb induced typical phase 2 genes: glutamate cysteine ligase catalytic subunit (GCLC) and glutathione-S-transferase subunit-PI (GST-P1), by real-time PCR. To investigate the molecular mechanism of this induction, we used quinone oxidoreductase 1 (NQO1) - Antioxidant response element (ARE) reporter assay and found that EGb activated the activity of the wild type but not the one with ARE mutated. It indicated that EGb induced these genes through ARE, a cis-acting motif located in the promoter region of nearly all phase 2 genes. Since nuclear factor erythroid 2-related factor 2 (Nrf2) binds ARE to enhance the expression of phase 2 genes, we detected the Nrf2 content in nucleus and found an accumulation of Nrf2 stimulated by EGb. In a further test of Kelch-like ECH-associated protein 1 (Keap1), the repression protein of Nrf2 in the cytosol under testing condition, we found that Keap1 content was inhibited by EGb and then more Nrf2 would be released to translocate into nucleus. Thus, EGb was testified for the first time to induce the phase 2 genes through the Keap1-Nrf2-ARE signaling pathway, which is (or part of) the antioxidant mechanism of EGb. (c) 2007 Elsevier Inc. All rights reserved.