NF kappa B and AP-1 mediate transcriptional responses to oxidative stress in skeletal muscle cells.
NF kappa B and AP-1 mediate transcriptional responses to oxidative stress in skeletal muscle cells.
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发表时间：
2001
影响因子：
7.4
通讯作者：
L. Z. Zhou;A. P. Johnson;T. Rando
中科院分区：
文献类型：
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作者：
L. Z. Zhou;A. P. Johnson;T. Rando
诱导细胞防御机制以响应环境挑战的能力是真核和原核细胞的基本性质。我们以前已经表明，氧化的挑战导致抗氧化酶，特别是谷胱甘肽过氧化物酶（GPx）和过氧化氢酶（CAT），在小鼠骨骼肌的增加。目前研究的重点是负责这些增加的转录调控机制。小鼠GPx和CAT基因的序列分析揭示了NF κ B B和AP-1的假定结合基序，这些转录调节因子在各种组织中响应氧化应激而被激活。为了测试NF κ B或AP-1是否可能介导经受氧化应激的肌细胞中GPx和CAT的诱导，我们首先表征了促氧化剂对它们的激活。电泳迁移率变动分析表明，氧化应激导致的DNA结合的NF κ B B在分化的肌肉细胞的增加。NF κ B复合物包括p50/p65异二聚体、p50同二聚体和p50/RelB异二聚体。AP-1也被激活，但动力学比NF κ B B慢。AP-1复合物的主要成分是由c-jun/fos组成的异源二聚体。为了测试NF κ B-或AP-1-依赖性转录激活的氧化还原调节，使表达κ B/荧光素酶或TRE/荧光素酶报告基因构建体的肌细胞经受氧化应激。促氧化剂处理导致表达任一构建体的细胞中荧光素酶活性增加。为了测试NF κ B是否介导氧化剂诱导的GPx和CAT表达的增加，我们用NF κ B的反式显性抑制剂（I κ B α）或显性负性抑制剂（Delta SP）转染细胞。这两种抑制剂阻断了50%以上的抗氧化基因表达的诱导。总之，我们的研究结果表明，NF κ B B和AP-1是骨骼肌中氧化还原反应基因表达的重要介质，并且至少NF κ B B积极参与了GPx和CAT在氧化应激反应中的上调。
The ability to induce cellular defense mechanisms in response to environmental challenges is a fundamental property of eukaryotic and prokaryotic cells. We have previously shown that oxidative challenges lead to an increase in antioxidant enzymes, particularly glutathione peroxidase (GPx) and catalase (CAT), in mouse skeletal muscle. The focus of the current studies is the transcriptional regulatory mechanisms responsible for these increases. Sequence analysis of the mouse GPx and CAT genes revealed putative binding motifs for NF kappa B and AP-1, transcriptional regulators that are activated in response to oxidative stress in various tissues. To test whether NF kappa B or AP-1 might be mediating the induction of GPx and CAT in muscle cells subjected to oxidative stress, we first characterized their activation by pro-oxidants. Electrophoretic mobility shift assays showed that oxidative stress led to increases in the DNA binding of NF kappa B in differentiated muscle cells. The NF kappa B complexes included a p50/p65 heterodimer, a p50 homodimer, and a p50/RelB heterodimer. AP-1 was also activated, but with slower kinetics than that of NF kappa B. The major component of the AP-1 complexes was a heterodimer composed of c-jun/fos. To test for redox regulation of NF kappa B- or AP-1-dependent transcriptional activation, muscle cells expressing either kappa B/luciferase or TRE/luciferase reporter constructs were subjected to oxidative stress. Pro-oxidant treatment resulted in increased luciferase activity in cells expressing either construct. To test whether NF kappa B mediates oxidant-induced increases of GPx and CAT expression, we transfected cells with either a transdominant inhibitor (I kappa B alpha) or a dominant-negative inhibitor (Delta SP) of NF kappa B. Both inhibitors blocked the induction of antioxidant gene expression by more than 50%. In summary, our results suggest that NF kappa B and AP-1 are important mediators of redox-responsive gene expression in skeletal muscle, and that at least NF kappa B is actively involved in the upregulation of the GPx and CAT in response to oxidative stress.