Phosphorylated Map Kinase (ERK1, ERK2) Expression is Associated with Early Tau Deposition in Neurones and Glial Cells, but not with Increased Nuclear DNA Vulnerability and Cell Death, in Alzheimer Disease, Pick's Disease, Progressive Supranuclear Palsy and Corticobasal Degeneration
Phosphorylated Map Kinase (ERK1, ERK2) Expression is Associated with Early Tau Deposition in Neurones and Glial Cells, but not with Increased Nuclear DNA Vulnerability and Cell Death, in Alzheimer Disease, Pick's Disease, Progressive Supranuclear Palsy and Corticobasal Degeneration
复制标题
DOI：
10.1111/j.1750-3639.2001.tb00387.x
复制
发表时间：
2001-04
期刊：
影响因子：
6.4
通讯作者：
I. Ferrer;R. Blanco;M. Carmona;R. Ribera;E. Goutan;B. Puig;M. Rey;A. Cardozo;F. Viñals;T. Ribalta
中科院分区：
文献类型：
--
作者：
I. Ferrer;R. Blanco;M. Carmona;R. Ribera;E. Goutan;B. Puig;M. Rey;A. Cardozo;F. Viñals;T. Ribalta
神经元和神经胶质细胞中异常的tau蛋白磷酸化和沉积是tau蛋白病的主要特征之一。本研究通过蛋白质印迹、单标记和双标记免疫组织化学以及p21 Ras活化测定来检查tau蛋白磷酸化的Ras/MEK/ERK通路在阿尔茨海默病（AD）、皮克病（PiD）、进行性核上性麻痹（PSP）和皮质基底节变性（CBD）中的参与。由于该途径也在细胞死亡和细胞存活的几种范式中被激活，因此还使用双标记免疫组织化学和核DNA片段的原位末端标记来分析激活的ERK表达，以可视化具有增加的核DNA脆弱性的细胞中的激活的ERK。MEK 1抗体识别一条45 kD的条带，其识别磷酸化非依赖性MEK 1，其表达水平在患病大脑中未改变。ERK抗体识别一条42 kD的条带，对应于磷酸化非依赖性ERK 2的分子量;在AD、PiD、PSP和CBD中，单个细胞中ERK的表达水平以及免疫反应性没有变化。抗体MAPK-P区分了检测磷酸化ERK 1和ERK 2的44 kD和42 kD两条带。如蛋白质印迹法所见，MAPK-P表达水平在AD、PiD、PSP和CBD中显著增加。此外，免疫组织化学揭示了AD中神经元细胞质中的颗粒状沉淀物，主要是在表现出早期tau沉积的神经元亚群中，而具有发达的神经元缠结的神经元不太常见免疫染色。MAPK-P还修饰PiD中具有Pick小体的神经元，PSP和CBD中神经元中的早期tau沉积，以及CBD中的皮质无色神经元。此外，如双标记免疫组织化学所示，在PSP和CBD中的大量tau阳性胶质细胞中发现了强MAPK-P免疫反应性。然而，在AD、PiD、PSP和CBD中未发现磷酸化ERK免疫反应性增强和核DNA片段化的共定位。最后，与对照组相比，AD病例中激活的Ras表达水平增加。这些结果表明磷酸化（活性）ERK表达增加与tau蛋白病中神经元和神经胶质细胞中的早期tau蛋白沉积相关，并表明活化的Ras作为AD中tau蛋白磷酸化的MEK/ERK途径的上游活化剂。
Abnormal tau phosphorylation and deposition in neurones and glial cells is one of the major features in tau pathies. The present study examines the involvement of the Ras/MEK/ERK pathway of tau phosphorylation in Alzheimer disease (AD), Pick's disease (PiD), progressive supranuclear palsy (PSP) and corticobasal degeneration (CBD), by Western blotting, single and double‐labelling immunohistochemistry, and p21Ras activation assay. Since this pathway is also activated in several paradigms of cell death and cell survival, activated ERK expression is also analysed with double‐labelling immunohistochemistry and in situ end‐labelling of nuclear DNA fragmentation to visualise activated ERK in cells with increased nuclear DNA vulnerability. The MEK1 antibody recognises one band of 45 kD that identifies phosphorylation‐independent MEK1, whose expression levels are not modified in diseased brains. The ERK antibody recognises one band of 42 kD corresponding to the molecular weight of phosphorylation‐independent ERK2; the expression levels, as well as the immunoreactivity of ERK in individual cells, is not changed in AD, PiD, PSP and CBD. The antibody MAPK‐P distinguishes two bands of 44 kD and 42 kD that detect phosphorylated ERK1 and ERK2. MAPK‐P expression levels, as seen with Western blotting, are markedly increased in AD, PiD, PSP and CBD. Moreover, immunohistochemistry discloses granular precipitates in the cytoplasm of neurones in AD, mainly in a subpopulation of neurones exhibiting early tau deposition, whereas neurones with developed neurofibrillary tangles are less commonly immunostained. MAPK‐P also decorates neurones with Pick bodies in PiD, early tau deposition in neurones in PSP and CBD, and cortical achromatic neurones in CBD. In addition, strong MAPK‐P immunoreactivity is found in large numbers of tau‐positive glial cells in PSP and CBD, as seen with double‐labelling immunohistochemistry. Yet no co‐localisation of enhanced phosphorylated ERK immunoreactivity and nuclear DNA fragmentation is found in AD, PiD, PSP and CBD. Finally, activated Ras expression levels are increased in AD cases when compared with controls. These results demonstrate increased phosphorylated (active) ERK expression in association with early tau deposition in neurones and glial cells in taupathies, and suggest activated Ras as the upstream activator of the MEK/ERK pathway of tau phosphorylation in AD.