Giovannini M G, Cerbai F, Bellucci A, Melani C, Grossi C, Bartolozzi C, Nosi D, Casamenti F
Dipartimento di Farmacologia, University of Florence, Florence, Italy.
Neuroscience. 2008 May 15;153(3):618-33. doi: 10.1016/j.neuroscience.2008.02.061. Epub 2008 Mar 6.
Transgenic Centre for Research in Neurodegenerative Diseases 8 (TgCRND8) mice expressing a double mutant form of human amyloid precursor protein represent a good model of Alzheimer's disease, and can be useful to clarify the involvement of mitogen-activated protein kinases (MAPK) dysregulation in the pathophysiology of this neurodegenerative disorder. Activation of extracellular regulated kinase (ERK) 1/2, jun kinase (JNK) and p38MAPK was studied in the hippocampus of 7-month-old TgCRND8 mice by immunohistochemistry and Western blot analysis using antibodies selective for the phosphorylated, and thus active, forms of the enzymes. We demonstrated that the three main MAPK pathways were differentially activated in cells of the hippocampus of TgCRND8 mice in comparison to wild type (Wt) littermates, p38MAPK and JNK being more activated, while ERK less activated. p38MAPK was significantly activated in microglia, astrocytes and neurons, around and distant from the plaques. JNK was highly activated in cells closely surrounding the plaques. No difference was observed in the activation of the two major bands of JNK, at a molecular weight of 46 kDa and 54 kDa. These data indicate the possible involvement of p38MAPK and JNK pathways dysregulation in the pathogenesis of Alzheimer's disease. The ERK2 isoform of the ERK pathway was less activated in the hippocampal dentate gyrus of Tg mice in basal conditions. Furthermore activation of the ERK pathway by ex vivo cholinergic stimulation with carbachol caused significantly higher activation of ERK in the hippocampus of Wt mice than in Tg mice. These findings may pose a molecular basis for the memory disruption of Alzheimer's disease, since proper functioning of the basal forebrain cholinergic neurons and of ERK2 is critical for memory formation.
表达人淀粉样前体蛋白双突变形式的神经退行性疾病研究转基因中心8(TgCRND8)小鼠是阿尔茨海默病的良好模型,有助于阐明丝裂原活化蛋白激酶(MAPK)失调在这种神经退行性疾病病理生理学中的作用。通过免疫组织化学和蛋白质印迹分析,使用对磷酸化(即活性)形式的酶具有选择性的抗体,研究了7月龄TgCRND8小鼠海马中细胞外调节激酶(ERK)1/2、JUN激酶(JNK)和p38MAPK的激活情况。我们证明,与野生型(Wt)同窝小鼠相比,TgCRND8小鼠海马细胞中三种主要的MAPK途径被不同程度地激活,p38MAPK和JNK激活程度更高,而ERK激活程度较低。p38MAPK在斑块周围和远处的小胶质细胞、星形胶质细胞和神经元中显著激活。JNK在斑块周围紧密环绕的细胞中高度激活。在分子量为46 kDa和54 kDa的JNK两条主要条带的激活方面未观察到差异。这些数据表明p38MAPK和JNK途径失调可能参与阿尔茨海默病的发病机制。在基础条件下,Tg小鼠海马齿状回中ERK途径的ERK2亚型激活程度较低。此外,用卡巴胆碱进行离体胆碱能刺激激活ERK途径后,Wt小鼠海马中ERK的激活程度明显高于Tg小鼠。这些发现可能为阿尔茨海默病的记忆障碍提供分子基础,因为基底前脑胆碱能神经元和ERK2的正常功能对记忆形成至关重要。