Metabohom of 4-hydroxy-trans-2-nonenal by central nervous system mitochondria is dependent on age and NAD+ availability
Metabohom of 4-hydroxy-trans-2-nonenal by central nervous system mitochondria is dependent on age and NAD+ availability
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DOI：
10.1021/tx049843k
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发表时间：
2004-09-01
影响因子：
4.1
通讯作者：
Picklo, MJ
中科院分区：
文献类型：
--
作者：
Meyer, MJ;Mosely, DE;Picklo, MJ
脂质过氧化和线粒体功能障碍与包括阿尔茨海默病和帕金森病在内的多种神经退行性疾病有关。4-羟基-反式-2-壬烯醛(HNE)是一种主要的神经毒性脂质过氧化产物，在这些疾病中水平升高。本实验室以前的数据表明，线粒体在HNE的解毒过程中起着重要的作用，特别是通过将HNE氧化成4-羟基-反式-2-壬烯酸(HNE-ACID)。在这项工作中，我们研究了当与完整的、良好耦合的大鼠脑线粒体孵育时HNE的处置。我们的结果表明，HNE的损失是时间和浓度依赖的、可饱和的，Km值为28.0+/-11.8umHNE，V-max为10+/-1.7nmol/min/mg。HNE酸的形成是可饱和的，K-M为25.3+/-6.3um HNe，V-max为4.4+/-0.43nmol/min/mg。HNE-谷胱甘肽加合物和HNE-蛋白质加合物的形成只占HNE消耗量的一小部分。从老年动物分离的大鼠脑线粒体中HNE代谢显著降低。然后，我们验证了线粒体NADH/NAD(+)比例调节基质醛脱氢酶活性的假设。我们的结果表明，与琥珀酸相比，丙酮酸和苹果酸作为底物时，HNE的氧化受到了更大程度的抑制。呼吸底物的复合体I抑制进一步阻断了HNE的解毒作用。鱼藤酮(100 NM)对呼吸抑制15%，而HNE酸的形成减少到对照水平的72%。这些结果表明，线粒体醛的原位解毒作用受到NAD(+)可用性和复合体I活性降低的影响。
Lipid peroxidation and mitochondrial dysfunction are associated with multiple neurodegenerative disorders including Alzheimer's disease and Parkinson's disease. 4-Hydroxy-trans-2-nonenal (HNE) is a major, neurotoxic product of lipid peroxidation whose levels are elevated in these diseases. Previous data from this laboratory demonstrate that mitochondria play an important role in the detoxification of HNE particularly through the oxidation of HNE to 4-hydroxy-trans-2-nonenoate (HNEAcid). In this work, we examined the disposition of HNE when incubated with intact, well-coupled, rat brain mitochondria. Our results demonstrated that HNE loss occurred in a time- and concentration-dependent, saturable manner with a Km of 28.0 +/- 11.8 muM HNE and a V-Max Of 10 +/- 1.7 nmol/min/mg. HNEAcid formation occurred in a saturable manner with a K-M of 25.3 +/- 6.3 muM HNE and a V-Max of 4.4 +/- 0.43 nmol/min/mg. The formation of HNE-glutathione adducts and HNE-protein adducts comprised only a small percentage of HNE consumption. HNE metabolism was significantly diminished in rat brain mitochondria isolated from older animals. We then tested the hypothesis that the mitochondrial NADH/NAD(+) ratio regulated matrix aldehyde dehydrogenase activity. Our results demonstrate that HNE oxidation was significantly inhibited to a greater extent with pyruvate and malate as substrates vs succinate. Complex I inhibition with respiratory substrates further blocked HNE detoxification. Rotenone (100 nM) inhibited respiration by 15% whereas HNEAcid formation was decreased to 72% of control levels. These results demonstrate that in situ mitochondrial aldehyde detoxification is affected by decrements in NAD(+) availability and complex I activity.