乙醛脱氢酶2(ALDH2)是一种线粒体酶,可通过脂质过氧化产物的解毒来减少细胞损伤,4-羟基-2-壬烯醛(羟基壬烯醛)。它是通过油炸富含亚油酸的食用油而外源产生的和/或通过氧化参与生物膜的脂肪酸而内源产生的。虽然其对人体健康的毒性被广泛接受,潜在的机制长期以来仍然未知。1998年,山岛等人。已将“钙蛋白酶-组织蛋白酶假说”表述为缺血性神经元死亡的分子机制。随后,他们发现钙蛋白酶可以裂解Hsp70.1,Hsp70.1在关键位点Arg469被羟基壬烯醛诱导的羰基化作用后变得脆弱.由于是引起溶酶体膜破裂的关键畸变,他们认为,阿尔茨海默病的神经元死亡类似地发生于慢性缺血,通过由羟基壬烯醛触发的钙蛋白酶-组织蛋白酶级联反应。近三十年来,淀粉样β(Aβ)肽被认为是阿尔茨海默病的根源物质。然而,由于Aβ沉积与神经元死亡或痴呆的发生之间的相关性不明显,以及迄今为止在阿尔茨海默病患者中测试的抗Aβ药物的阴性结果,“淀粉样蛋白级联假说”的强度已被削弱。最近的研究表明,羟基壬烯醛不仅在大脑中是程序性细胞死亡的介质,而且在肝脏中,胰腺,心,等。羟基壬烯醛的增加被认为是阿尔茨海默病发展的早期事件。这篇评论旨在提出走出隧道的方法,关注羟基壬烯醛在这种疾病中的意义。在这里,通过关注具有伴侣蛋白和溶酶体稳定剂双重功能的Hsp70.1,讨论了阿尔茨海默神经元死亡的机制。我们认为Aβ不是阿尔茨海默病的罪魁祸首,但仅仅是由羟基壬烯醛诱导的Hsp70.1疾病引起的自噬/溶酶体衰竭的副产物。增强ALDH2活性以解毒羟基壬烯醛成为预防和治疗阿尔茨海默病的有希望的策略。
Aldehyde dehydrogenase 2 (ALDH2) is a mitochondrial enzyme that reduces cell injuries via detoxification of lipid-peroxidation product, 4-hydroxy-2-nonenal (hydroxynonenal). It is generated exogenously via deep-frying of linoleic acid-rich cooking oils and/or endogenously via oxidation of fatty acids involved in biomembranes. Although its toxicity for human health is widely accepted, the underlying mechanism long remained unknown. In 1998, Yamashima et al. have formulated the \"calpain-cathepsin hypothesis\" as a molecular mechanism of ischemic neuronal death. Subsequently, they found that calpain cleaves Hsp70.1 which became vulnerable after the hydroxynonenal-induced carbonylation at the key site Arg469. Since it is the pivotal aberration that induces lysosomal membrane rupture, they suggested that neuronal death in Alzheimer\'s disease similarly occurs by chronic ischemia via the calpain-cathepsin cascade triggered by hydroxynonenal. For nearly three decades, amyloid β (Aβ) peptide was thought to be a root substance of Alzheimer\'s disease. However, because of both the insignificant correlations between Aβ depositions and occurrence of neuronal death or dementia, and the negative results of anti-Aβ medicines tested so far in the patients with Alzheimer\'s disease, the strength of the \"amyloid cascade hypothesis\" has been weakened. Recent works have suggested that hydroxynonenal is a mediator of programmed cell death not only in the brain, but also in the liver, pancreas, heart, etc. Increment of hydroxynonenal was considered an early event in the development of Alzheimer\'s disease. This review aims at suggesting ways out of the tunnel, focusing on the implication of hydroxynonenal in this disease. Herein, the mechanism of Alzheimer neuronal death is discussed by focusing on Hsp70.1 with a dual function as chaperone protein and lysosomal stabilizer. We suggest that Aβ is not a culprit of Alzheimer\'s disease, but merely a byproduct of autophagy/lysosomal failure resulting from hydroxynonenal-induced Hsp70.1 disorder. Enhancing ALDH2 activity to detoxify hydroxynonenal emerges as a promising strategy for preventing and treating Alzheimer\'s disease.