EVIDENCE FOR THE ACTIVATION OF THE SIGNAL-RESPONSIVE PHOSPHOLIPASE A(2) BY EXOGENOUS HYDROGEN-PEROXIDE
EVIDENCE FOR THE ACTIVATION OF THE SIGNAL-RESPONSIVE PHOSPHOLIPASE A(2) BY EXOGENOUS HYDROGEN-PEROXIDE
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DOI：
10.1016/0006-2952(95)00195-6
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发表时间：
1995-09-07
影响因子：
5.8
通讯作者：
MOLDEUS, P
中科院分区：
文献类型：
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作者：
BOYER, CS;BANNENBERG, GL;MOLDEUS, P
用过氧化氢处理培养的牛内皮细胞，导致花生四烯酸释放的细胞内事件的特点。过氧化氢刺激的花生四烯酸的释放是时间和剂量依赖性的，最大释放达到15分钟后，加入100 μ M的过氧化氢。过氧化氢刺激的花生四烯酸释放被磷脂酶A（2）抑制剂奎纳克林阻断。用过氧化氢处理细胞并没有导致油酸的释放，这表明过氧化氢对花生四烯酸特异性磷脂酶发挥了作用。用抗氧化剂、过渡金属螯合剂和羟基自由基清除剂预处理细胞不影响过氧化氢刺激的花生四烯酸释放，表明对过氧化氢的反应不是氧自由基介导的。对过氧化氢的反应似乎不是钙依赖性的，这是由于以下两个观察结果：（a）将FURA 2负载的细胞暴露于足以释放花生四烯酸的浓度的过氧化氢后，未观察到细胞内钙的增加，和（B）在负载细胞内钙螯合剂BAPTA的细胞中未检测到释放反应的变化。花生四烯酸释放的显着抑制时，看到的细胞与蛋白激酶C的抑制剂，但不与酪氨酸激酶抑制剂预处理。这些研究的结果表明，过氧化氢刺激的花生四烯酸释放是由一种特定的信号响应性磷脂酶A介导的（2），并且该过程不是通过脂质过氧化或钙的作用介导的，而是细胞内激酶活性的刺激是该反应所必需的。
The intracellular events that lead to arachidonic acid release from bovine endothelial cells in culture treated with hydrogen peroxide were characterized. The hydrogen peroxide-stimulated release of arachidonic acid was time- and dose-dependent, with maximal release achieved at 15 minutes after the addition of 100 mu M hydrogen peroxide. Hydrogen peroxide-stimulated release of arachidonic acid was blocked with the phospholipase A(2) inhibitor quinacrine. Treatment of the cells with hydrogen peroxide did not result in liberation of oleic acid, indicating that hydrogen peroxide exercised its effect on an arachidonate-specific phospholipase. Pretreatment of the cells with antioxidants, transition metal chelators, and hydroxyl radical scavengers did not affect the hydrogen peroxide-stimulated arachidonic acid release, indicating that the response to hydrogen peroxide is not oxygen radical-mediated. The response to hydrogen peroxide does not appear to be calcium-dependent, due to me following two observations: (a) No increase in intracellular calcium was seen upon exposure of the FURA2-loaded cells to hydrogen peroxide at concentrations sufficient to release arachidonic acid, and (b) no change in the release response was detected in cells loaded with the intracellular calcium chelator BAPTA. Significant inhibition of arachidonic acid release was seen when the cells were pretreated with inhibitors of protein kinase C, but not with inhibitors of tyrosine kinase. The results of these studies indicate that hydrogen peroxide-stimulated arachidonic acid release is mediated by a specific signal-responsive phospholipase A(2), and that this process is not mediated via the actions of either lipid peroxidation or calcium but, rather, that a stimulation of intracellular kinase activity is necessary for this response.