Department of Cell Biology and Physiology, University of New Mexico - Health Sciences Center, MSC08 4750 1 University of New Mexico, Albuquerque, NM, 87131-0001, USA.
Neurochem Res. 2018 Mar;43(3):609-618. doi: 10.1007/s11064-017-2456-9. Epub 2017 Dec 20.
This study was conducted to further our understanding about the link between lipid peroxidation and protein carbonylation in rat brain slices incubated with the glutathione (GSH)-depletor diethyl maleate. Using this in vitro system of oxidative stress, we found that there is a significant lag between the appearance of carbonylated proteins and GSH depletion, which seems to be due to the removal of oxidized species early on in the incubation by the mitochondrial Lon protease. Upon acute GSH depletion, protein carbonyls accumulated mostly in mitochondria and to a lesser degree in other subcellular fractions that also contain high levels of polyunsaturated lipids. This result is consistent with our previous findings suggesting that lipid hydroperoxides mediate the oxidation of proteins in this system. However, these lipid hydroperoxides are not produced by oxidation of free arachidonic acid or other polyunsaturated free fatty acids by lipooxygenases or cyclooxygenases. Finally, γ-glutamyl semialdehyde and 2-amino-adipic semialdehyde were identified by HPLC as the carbonyl-containing amino acid residues, indicating that proteins are carbonylated by metal ion-catalyzed oxidation of lysine, arginine and proline residues. The present findings are important in the context of neurological disorders that exhibit increased lipid peroxidation and protein carbonylation, such as Parkinson's disease, Alzheimer's disease, and multiple sclerosis.
本研究旨在进一步了解谷胱甘肽（GSH）耗竭剂马来酸二乙酯孵育的大鼠脑片中脂质过氧化与蛋白质羰基化之间的联系。使用这种体外氧化应激系统，我们发现，在孵育过程中，氧化物种的早期去除似乎导致了羰基化蛋白的出现与 GSH 耗竭之间存在显著的滞后，这种早期去除是由线粒体 Lon 蛋白酶完成的。在急性 GSH 耗竭时，蛋白质羰基主要积累在线粒体中，在其他含有高浓度多不饱和脂质的亚细胞部分中也有一定程度的积累。这一结果与我们之前的发现一致，即脂质氢过氧化物介导了该系统中蛋白质的氧化。然而，这些脂质氢过氧化物不是由脂氧合酶或环氧化酶氧化游离花生四烯酸或其他多不饱和游离脂肪酸产生的。最后，通过 HPLC 鉴定出 γ-谷氨酰半醛和 2-氨基己二酸半醛是含有羰基的氨基酸残基，表明蛋白质通过金属离子催化的赖氨酸、精氨酸和脯氨酸残基氧化而发生羰基化。这些发现对于表现出脂质过氧化和蛋白质羰基化增加的神经紊乱疾病（如帕金森病、阿尔茨海默病和多发性硬化症）具有重要意义。
