STUDIES ON FUNCTIONS OF THIOREDOXIN REDUCTASE IN DETOXIFICATION OF HEAVY METALS

硫氧还蛋白还原酶重金属解毒作用的研究

• 批准号: 16590093
• 负责人: HARA Shuntaro
• 金额: $ 2.24万
• 依托单位: SHOWA UNIVERSITY (2005)Kitasato University (2004)
• 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-16590093/
• 关键词: THIOREDOXIN REDUCTASE; HEAVY METALS; CADMIUM; NF-E2-RELATED FACTOR-2; ANTIOXIDATIVE ENZYME; siRNA; ヒ素; 低酸素応答性転写因子; 貴金属; 血管内皮細胞; 遺伝子発現; Nrf2

The mammalian thioredoxin reductase (TrxR) is a selenocysteine-containing flavoprotein that regulates the thioredoxin system, one of the major systems that maintain the intracellular redox balance. To date, three TrxR isozymes, TrxR1, TrxR2 and TrxR3, have been identified. We previously reported that TrxR1 was induced by heavy metals such as cadmium (Cd) and arsenite (As). In this study, the functions of TrxR1 in detoxification of heavy metals were investigated as follows :(1)Transcriptional regulation of Cd-induced TrxR1 expression-Treatment of bovine arterial endothelial cells with Cd enhanced the promoter activity of the 5'-flanking region of human TrxR1 gene (nucleotides -1692 to +49). Deletion and site-directed mutation of antioxidant responsive element (ARE) (nucleotide -62 to -48) in this region abolished the response to Cd. Overexpression of NF-E2-related factor-2 (Nrf2) augmented the TrxR1 promoter activity. These results indicated that Cd-induced TrxR1 gene expression is mediated by the activation of Nrf2 and its binding to ARE in the TrxR1 gene promoter. We further found that in addition to Cd, the activators of Nrf2, such as diethyl maleate (DEM) and As, induced both TrxR1 and Trx gene expression. Nrf2 might play an important role in the regulation of the cellular Trx system consisting of Trx and TrxR.(2)Involvement of TrxR1 in cellular defense against heavy metals-We silenced the expression of TrxR1 in HeLa cells by using short-interfering RNA and found that the gene silencing of TrxR1 had a dual effect on Cd- and As-induced celldeath, depending on the concentration of heavy metals. The TrxR1 silencing increased the sensitivity toward a low dose of heavy metals but decreased the sensitivity toward a high dose of heavy metals. These results suggested that TrxR1 might play an important role in the cellular defense system against heavy metals in two ways.

哺乳动物硫氧还蛋白还原酶（TRXR）是一种符合硒代半胱氨酸的黄蛋白，可调节硫氧还蛋白系统，硫氧还蛋白系统是维持细胞内氧化还原平衡的主要系统之一。迄今为止，已经鉴定出三个TRXR同工酶TRXR1，TRXR2和TRXR3。我们先前报道说，TRXR1是由诸如镉（CD）和砷（AS）等重金属诱导的。在这项研究中，TRXR1在重金属排毒中的功能如下：（1）CD诱导的TRXR1 TRXR1的转录调控牛动脉内皮细胞的CD具有CD的表达 - 增强了人类TRXR1基因的5'-芬兰克（Humant）基因（核苷酸核苷酸-11692 to y49 to +49）的启动子活性。该区域中抗氧化剂响应元件的缺失和定位突变（核苷酸-62至-48）消除了对CD的反应。 NF-E2相关因子2（NRF2）的过表达增强了TRXR1启动子活性。这些结果表明，CD诱导的TRXR1基因表达是由NRF2的激活介导的，其与TRXR1基因启动子中的结合介导。我们进一步发现，除了CD之外，NRF2的活化剂（例如二乙基乳腺癌（DEM））以及AS还诱导TRXR1和TRX基因表达。 Nrf2 might play an important role in the regulation of the cellular Trx system consisting of Trx and TrxR.(2)Involvement of TrxR1 in cellular defense against heavy metals-We silenced the expression of TrxR1 in HeLa cells by using short-interfering RNA and found that the gene silencing of TrxR1 had a dual effect on Cd- and As-induced celldeath, depending on the concentration of heavy metals. TRXR1沉默增加了对低剂量重金属的敏感性，但降低了对高剂量重金属的敏感性。这些结果表明，TRXR1在针对重金属的细胞防御系统中可能起着重要作用。

项目成果

Short-interfering RNA-mediated Silencing of Thioredoxin Reductase 1 Alters the Sensitivity of HeLa Cells toward Cadmium

短干扰 RNA 介导的硫氧还蛋白还原酶 1 沉默改变了 HeLa 细胞对镉的敏感性

• 发表时间: 2006
• 期刊: Biological and Pharmaceutical Bulletin 29・3
• 作者: C.Cuiping;R.Tanaka;Y.Okuda;N.Ikota;H.Yamamoto;S.Urano;T.Ozawa;K.Anzai;西本 理恵 ほか
• 通讯作者: 西本 理恵 ほか

Transcriptional Regulation of Thioredoxin Reductase 1 Expression by Cadmium in Vascular Endothelial Cells

血管内皮细胞中镉对硫氧还蛋白还原酶 1 表达的转录调节

• 发表时间: 2005
• 期刊: Journal of Cellular Physiology 203・3
• 作者: Hashimoto Y;Kaneko Y;Tsukamoto E;Frankowski H;Kouyama K;Kita Y;Niikura T;Aiso S;Bredesen DE;Matsuoka M;Nishimoto I;Kitamura et al.分担(R.C.Gupta編集);Tetsushi Watanabe;櫻井貴子ほか
• 通讯作者: 櫻井貴子ほか