Neely M D, Sidell K R, Graham D G, Montine T J
Department of Pathology, Vanderbilt University, Nashville, Tennessee 37232-2561, USA.
J Neurochem. 1999 Jun;72(6):2323-33. doi: 10.1046/j.1471-4159.1999.0722323.x.
Oxidative stress is believed to be an important factor in the development of age-related neurodegenerative diseases such as Alzheimer's disease (AD). The CNS is enriched in polyunsaturated fatty acids and is therefore particularly vulnerable to lipid peroxidation. Indeed, accumulation of lipid peroxidation products has been demonstrated in affected regions in brains of AD patients. Another feature of AD is a change in neuronal microtubule organization. A possible causal relationship between lipid peroxidation products and changes in neuronal cell motility and cytoskeleton has not been investigated. We show here that 4-hydroxy-2(E)-nonenal (HNE), a major product of lipid peroxidation, inhibits neurite outgrowth and disrupts microtubules in Neuro 2A cells. The effect of HNE on microtubules was rapid, being observed after incubation times as short as 15 min. HNE can react with target proteins by forming either Michael adducts or pyrrole adducts. 4-Oxononanal, an HNE analogue that can form only pyrrole adducts but not Michael adducts, had no effect on the microtubules. This suggests that the HNE-induced disruption of microtubules occurs via Michael addition. We also show that cellular tubulin is one of the major proteins modified by HNE and that the HNE adduction to tubulin occurs via Michael addition. Inhibition of neurite outgrowth, disruption of microtubules, and tubulin modification were observed at pathologically relevant HNE concentrations and were not accompanied by cytotoxicity. Our results show that these are proximal effects of HNE that may contribute to cytoskeletal alterations that occur in AD.
氧化应激被认为是诸如阿尔茨海默病（AD）等与年龄相关的神经退行性疾病发展过程中的一个重要因素。中枢神经系统富含多不饱和脂肪酸，因此特别容易受到脂质过氧化的影响。事实上，在AD患者大脑的受影响区域已证实存在脂质过氧化产物的积累。AD的另一个特征是神经元微管组织的改变。脂质过氧化产物与神经元细胞运动性和细胞骨架变化之间可能的因果关系尚未得到研究。我们在此表明，脂质过氧化的主要产物4-羟基-2（E）-壬烯醛（HNE）抑制Neuro 2A细胞中的神经突生长并破坏微管。HNE对微管的作用迅速，在短至15分钟的孵育时间后即可观察到。HNE可通过形成迈克尔加成物或吡咯加成物与靶蛋白反应。4-氧代壬醛是一种HNE类似物，只能形成吡咯加成物而不能形成迈克尔加成物，对微管没有影响。这表明HNE诱导的微管破坏是通过迈克尔加成发生的。我们还表明，细胞微管蛋白是被HNE修饰的主要蛋白质之一，并且HNE与微管蛋白的加成是通过迈克尔加成发生的。在病理相关的HNE浓度下观察到神经突生长的抑制、微管的破坏和微管蛋白的修饰，并且没有伴随细胞毒性。我们的结果表明，这些是HNE的近端效应，可能导致AD中发生的细胞骨架改变。
