Overexpression of copper-zinc superoxide dismutase attenuates acute activation of activator protein-1 after transient focal cerebral ischemia in mice
Overexpression of copper-zinc superoxide dismutase attenuates acute activation of activator protein-1 after transient focal cerebral ischemia in mice
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DOI：
10.1161/01.str.32.3.741
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发表时间：
2001-03-01
期刊：
影响因子：
8.3
通讯作者：
Chan, PH
中科院分区：
文献类型：
--
作者：
Huang, CY;Fujimura, M;Chan, PH
背景和目的--活性氧(ROS)与局灶性脑缺血(FCI)后的再灌注损伤有关。已知ROS调节转录因子的活性，如激活蛋白-1(AP-1)，它是一种由Jun和Fos家族成员组成的二聚体。利用铜锌超氧化物歧化酶(SOD1)高表达转基因小鼠和FCI后缩小脑梗塞体积的转基因小鼠，研究ROS在FCI后AP-1活性中的作用。方法：采用线栓法建立大脑中动脉阻塞再灌注模型。大脑中动脉阻断60min后，分别于安乐死前1h、2h、4h取材。免疫组织化学和Western blotting检测c-jun和c-Fos蛋白的表达。结果：在野生型小鼠中，c-jun和c-Fos在缺血皮质及其外缘有明显的急性激活。在SOD1转基因小鼠中，两者的表达都降低了。Western blotting证实SOD1的过度表达与缺血脑组织c-jun和c-Fos蛋白水平降低有关。电泳迁移率改变分析显示，在SOD1转基因小鼠中，观察到的野生型小鼠缺血增强的DNA结合活性降低。超位移分析表明c-jun参与了AP-1复合体的结合。结论SOD1的过表达抑制了小鼠短暂性脑缺血后AP-1的早期激活。这可能会阻断下游有害靶基因的表达，从而减少小鼠短暂性FCI后的梗塞体积。
Background and Purpose-Reactive oxygen species (ROS) have been implicated in reperfusion injury after focal cerebral ischemia (FCI). ROS are known to regulate the activity of transcription factors such as activator protein-1 (AP-1), which is a dimer consisting of members of the Jun and Fos families. We investigated the role of ROS in AP-1 activity after FCI using transgenic mice that overexpressed copper-zinc superoxide dismutase (SOD1) and that had reduced infarction volume after FCI.Methods-The SOD1 transgenic mice and their wild-type littermates were subjected to middle cerebral artery occlusion and reperfusion by intraluminal suture blockade. After 60 minutes of middle cerebral artery occlusion, mice were allowed to recover for 1, 2, and 4 hours before euthanasia. Protein expression of c-Jun and c-Fos was examined by immunohistochemistry and Western blotting. AP-1 DNA-protein binding activity was assessed by electrophoretic mobility shirt assays.Results-In wild-type mice, immunohistochemistry demonstrated acute c-Jun and c-Fos activation in ischemic cortex and its outer boundary. Expression of both was reduced in SOD1 transgenic mice. Western blotting confirmed that SOD1 overexpression was associated with reduced c-Jun and c-Fos protein levels in ischemic brain. Electrophoretic mobility shift assays revealed that the ischemia-enhanced DNA binding activity observed in wild-type mice was reduced in SOD1 transgenic mice. Supershift assays indicated that c-Jun participated in the bound AP-1 complex.Conclusions-SOD1 overexpression prevents early activation of AP-1 after transient FCI in mice. This may block the expression of downstream target genes that are injurious, thereby reducing the infarction volume after transient FCI in mice.