Neurofibrillary tangles (NFT) are one of the neuropathological hallmarks of Alzheimer disease (AD). Abnormally...
DENG Yan-Qiu, Xu Guo-Gang, Duan Ping, Wang Jian-Zhi* Department of Pathophysiology, Institute of Neuroscience, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, P.R.China Corresponding
Hyperphosphorylation of Tau in Alzheimer’s disease (AD) brain appears to be caused by a down-regulation of protein phosphatase 2A (PP2A). In this study, we selectively inhibited PP2A by injection of okadaic acid (OA) into the Meynert nucleus basalis of rats and found that 0.4 pmol of OA injection induced approximately 60% inhibition of PP2A 24 h after injection, 13% inhibition 48 h after injection and no obvious inhibition 72 h after injection. Hyperphosphorylation of Tau at Ser-198/Ser-199/Ser-202 and Ser-396/Ser-404 and spatial memory deficit of rats were induced 24 h after 0.4 pmol of OA injection. This study suggests that a down-regulation of PP2A may underlie abnormal hyperphosphorylation of cytoskeletal proteins leading to neurofibrillary degeneration in AD.
Alzheimer病(AD)中,异常过度磷酸化的tau蛋白会导致细胞骨架的异常并与神经元的死亡有关.在体外,细胞周期蛋白依赖性蛋白激酶5(cdk-5)能在大多数AD相关位点磷酸化tau蛋白.旨在整体水平研究cdk-5过度表达对大鼠微管相关蛋白tau的磷酸化及空间记忆的影响.结果显示,在大鼠海马区转染 cdk-5基因,24h后其局部表达增加,并使得抗体tau-1显色减弱,PHF-1和12e8显色增强,提示tau蛋白在Ser199/202,Ser396/404和Ser262/356位点过度磷酸化.此外,在水迷宫测试中,cdk-5转染鼠寻找安全平台所需时间比对照鼠明显延长,而转染后48 h cdk-5的表达较 24h时下降,同时伴有tau蛋白磷酸化程度的下降和空间记忆能力的改善.这些结果提示整体水平的cdk-5的过度表达会导致大鼠的空间记忆损伤,而过度磷酸化的tau蛋白可能参与了该病理过程.
AIM To study in vivo the effect of melatonin (MEL) deficit on the metabolism of Amyloid precursor protein (APP...
Ling Zhi-Qun, Wang Ze-Fen, Wang Jian-Zhi~(**) (Department of Pathophysiology, Tongji Medical College, Huazhong Science and Technical University, Wuhan, China)
