NON-CYCLOOXYGENASE-DERIVED PROSTANOIDS (F2-ISOPROSTANES) ARE FORMED INSITU ON PHOSPHOLIPIDS
NON-CYCLOOXYGENASE-DERIVED PROSTANOIDS (F2-ISOPROSTANES) ARE FORMED INSITU ON PHOSPHOLIPIDS
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DOI：
10.1073/pnas.89.22.10721
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发表时间：
1992-11-15
影响因子：
11.1
通讯作者：
ROBERTS, LJ
中科院分区：
文献类型：
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作者：
MORROW, JD;AWAD, JA;ROBERTS, LJ
我们最近报道了一系列生物活性前列腺素f2样化合物（f2 -异前列腺素）的发现，这些化合物是由游离自由基催化花生四烯酸过氧化作用产生的，不依赖于环加氧酶。由于磷脂容易发生过氧化，我们研究了f2 -异前列腺素可能在磷脂上原位形成的可能性。对这一假设的初步支持是，在用CCl4诱导脂质过氧化处理的大鼠肝脏中提取的脂质水解后，测量的游离f2 -异前列腺素水平比未处理的动物高100倍以上。此外，ccl4处理的大鼠肝脏中脂质相关f2 -异前列腺素水平的增加先于循环中游离化合物的出现，这表明游离化合物是由过氧化脂质的水解产生的。通过证明脂质提取物与蜂毒磷脂酶A2在体外孵育后释放游离f2 -异前列腺素，支持了这一概念。当用高效液相色谱分析这些脂质提取物时，水解后产生大量游离f2 -异前列腺素的组分比未氧化的磷脂酰胆碱以更大的极性保留体积被洗脱。用快速原子轰击质谱法对这些极性脂质进行分析，证实它们是含有f2 -异前列腺素的磷脂酰胆碱。因此，与环氧合酶衍生的类前列腺素不同，f2 -异前列腺素最初在磷脂上原位形成，随后被释放，可能是由磷脂酶预先形成的。f2 -异前列腺素磷脂的分子模型显示它们是明显扭曲的分子。因此，脂质双分子层中这些磷脂种类的形成可能对细胞膜流动性和完整性的改变起重要作用，这是众所周知的氧化损伤的后遗症。
We recently reported the discovery of a series of bioactive prostaglandin F2-like compounds (F2-isoprostanes) that are produced in vivo by free radical-catalyzed peroxidation of arachidonic acid independent of the cyclooxygenase enzyme. Inasmuch as phospholipids readily undergo peroxidation, we examined the possibility that F2-isoprostanes may be formed in situ on phospholipids. Initial support for this hypothesis was obtained by the finding that levels of free F2-isoprostanes measured after hydrolysis of lipids extracted from livers of rats treated with CCl4 to induce lipid peroxidation were more than 100-fold higher than levels in untreated animals. Further, increased levels of lipid-associated F2-isoprostanes in livers of CCl4-treated rats preceded the appearance of free compounds in the circulation, suggesting that the free compounds arose from hydrolysis of peroxidized lipids. This concept was supported by demonstrating that free F2-isoprostanes were released after incubation of lipid extracts with bee venom phospholipase A2 in vitro. When these lipid extracts were analyzed by HPLC, fractions that yielded large quantities of free F2-isoprostanes after hydrolysis eluted at a much more polar retention volume than nonoxidized phosphatidylcholine. Analysis of these polar lipids by fast atom bombardment mass spectrometry established that they were F2-isoprostane-containing species of phosphatidylcholine. Thus, unlike cyclooxygenase derived prostanoids, F2-isoprostanes are initially formed in situ on phospholipids, from which they are subsequently released preformed, presumably by phospholipases. Molecular modeling of F2-isoprostane-containing phospholipids reveals them to be remarkably distorted molecules. Thus, the formation of these phospholipid species in lipid bilayers may contribute in an important way to alterations in fluidity and integrity of cellular membranes, well-known sequelae of oxidant injury.