ZINC-mediated gene expression offers protection against H2O2-induced cytotoxicity
ZINC-mediated gene expression offers protection against H2O2-induced cytotoxicity
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DOI：
10.1016/j.taap.2004.10.008
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发表时间：
2005-06-15
影响因子：
3.8
通讯作者：
Hogstrand, C
中科院分区：
文献类型：
--
作者：
Chung, NJ;Walker, PA;Hogstrand, C
利用原代培养的虹鳟鱼鳃细胞研究了锌对活性氧（ROS）和H2 O2诱导的细胞凋亡的动员防御能力。鳃细胞用100 μ M硫酸锌预处理24小时，然后暴露于100或200 μ M H2 O2 24小时，或与100或200 μ M H2 O2一起暴露于100 μ M硫酸锌。金属硫蛋白-A（MTA）和金属硫蛋白-B（MTB）的mRNA水平增加锌或过氧化氢处理后，单独或组合。同样，谷胱甘肽S-转移酶（GST）和葡萄糖6-磷酸脱氢酶（G6 PD）的mRNA增加响应锌或H2 O2，或锌，然后H2 O2的顺序处理后。锌或H2 O2对MTA、MTB、GST和G6 PD mRNA水平的刺激作用可以通过添加膜渗透性锌螯合剂N，N，N '，N'-四（2-吡啶基甲基）乙二胺（TPEN）来阻断，这表明H2 O2诱导的这些基因的上调是锌依赖性的。用锌预处理保护细胞免受随后的细胞损伤和凋亡，如通过乳酸脱氢酶渗漏、线粒体脱氢酶活性（MTT测定）、半胱天冬酶-3活性和DNA片段化所评估的。相反，当鳃细胞与锌和H2 O2在同一时间共孵育，H2 O2的毒性高于单独用H2 O2处理后。它的结论是，锌有一个直接的促氧化作用时，与H2 O2一起管理，但锌的预处理抑制细胞毒性和细胞凋亡，通过间接的抗氧化作用。我们提出抗氧化作用是通过锌依赖性表达的几个基因编码的抗氧化蛋白（例如，MTA、MTB、G6PD和GST）。此外，明显的锌依赖性H2 O2诱导的抗氧化基因的表达表明，锌可能作为一种生理信号，介导的氧化应激反应。(c)2004年爱思唯尔公司All rights reserved.
The ability of zinc to mobilize defense against reactive oxygen species (ROS) and H2O2-induced apoptosis was studied using a primary culture of rainbow trout gill cells. Gill cells were pretreated for 24 h with 100 mu M ZnSO4 followed by 24-h exposure to 100 or 200 mu M H2O2, or were subjected to 100 mu M ZnSO4 together with 100 or 200 mu M H2O2. Metallothionein-A (MTA) and metallothionein-B (MTB) mRNA levels were increased after treatment with zinc or H2O2, separately or in combination. Similarly, mRNA for glutathione S-transferase (GST) and glucose 6-phosphate dehydrogenase (G6PD) were increased in response to either zinc or H2O2, or after sequential treatments with zinc followed by H2O2. The stimulatory effects of zinc or H2O2 on MTA, MTB, GST, and G6PD mRNA levels could be blocked by addition of the membrane permeable zinc chelator, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), suggesting that H2O2-induced upregulation of these genes is zinc-dependent. Pretreatment with zinc protected the cells from subsequent cell damage and apoptosis, as assessed by lactate dehydrogenase leakage, mitochondrial dehydrogenase activity (MTT assay), caspase-3 activity, and DNA fragmentation. In contrast, when gill cells were coincubated with zinc and H2O2 at the same time, H2O2 toxicity was higher than after treatment with H2O2 alone. It is concluded that zinc had a direct pro-oxidant effect when administered together with H2O2, but that pretreatment of zinc inhibited cytotoxicity and apoptosis through an indirect antioxidant action. We propose that the antioxidant action is manifested through zinc-dependent expression of several genes encoding antioxidant proteins (e.g., MTA, MTB, G6PD, and GST). Furthermore, the apparent zinc-dependency of H2O2-induced expression of antioxidant genes suggests that zinc might act as a physiological signal to mediate the response to oxidative stress. (c) 2004 Elsevier Inc. All rights reserved.