Investigation of mechanism of tauopathy and application for clinical diagnosis

1）我们已经制备了选择性识别四重复tau蛋白的抗体。（4R-tau）。应用该抗体检测进行性核上性麻痹（PSP）患者的脑组织，结果显示tau蛋白阳性的簇状星形胶质细胞、前缠结和头部均由4 R-tau蛋白组成，而4 R-tau蛋白阳性的簇状星形胶质细胞不与抗GFAP抗体反应。2）利用4 R-tau蛋白抗体建立脑脊液中4 R-tau蛋白的检测方法。3）我们在一个家族性tau蛋白病中发现了一个新的tau基因突变（L266 V（额颞叶痴呆和帕金森综合征与17号染色体相关），我们检查了该家系患者的大脑，发现了Pick小体样包涵体和独特的tau阳性星形细胞。4）我们报道了两个家族的两名P301 L tau突变患者，他们表现出不同的表型。两例患者的tau基因在三个位点的基因型不同，研究表明，他们没有共同的P301 L突变创始人，在患者2中观察到的两种较不常见的基因型中的任何一种可能是将P301 L突变表型修饰为具有突出帕金森症的不寻常临床特征的因素。5）采用定量RT-PCR方法，我们研究了PSP和皮质基底节变性（corticobasaldegeneration，CBD）患者额叶皮质和苍白球中tau mRNA亚型的表达水平。PSP组和CBD组CBD额叶皮质和苍白球的4 R/3R比值均显著高于对照组。tau mRNA亚型的表达模式与p-tau积累之间没有相关性。我们的研究结果表明，PSP和CBD的神经变性可以通过选择性剪接tau mRNA来调节，以产生高的4 R/3R比率，但其他因素，如转录后或翻译修饰，可能在PSP和CBD的特定神经变性的发病机制中发挥作用。

1)We have made an antibody which selectively recognized the four-repeat tau protein. (4R-tau). Using this antibody, we examined the brain tissue of the patients with progressive supranuclear palsy (PSP) and demonstrated that tau-positive tufted astrocyte, pretangle and theads were composed of 4R-tau and 4R-tau-positive tufted astrocytes were not reactive for anti-GFAP antibody.2)Using the antibody for 4R-tau, we are establishing the method for measure of 4R-tau in cerebrospinal fluid. The method is based on ELISA.3)We have found a new mutation of the tau gene (L266V) in a familial tauopathy (frontotemporal dementia and parkinsonism linked to chromosome 17) and we examined the brain of a patient of this kindred and demonstrated Pick body-like inclusions and unique tau-positive astrocytes.4)We have reported two patients of the two families with P301L tau mutation, who showed different phenotype. Their genotypes of the tau gene were different at three sites, and the studies suggested they do not share a common founder for P301L mutation and either of the two less prevalent genotypes observed in patient 2 may be the factor to modify the phenotype of P301L mutation into those unusual clinical features with prominent parkinsonism.5)Using quantitative RT-PCR method, we investigated the expression level of tau mRNA isoforms in the frontal cortex and globus pallidus of patients with PSP and corticobasal degeneration (CBD). The 4R/3R ratios in frontal cortices of CBD and globus pallidus of PSP and CBD were significantly higher than the control. There was no correlation between the expression patterns of tau mRNA isoforms and p-tau accumulation. Our findings suggest that neurodegeneration of PSP and CBD could be regulated by alternative splicing of tau mRNA to yield high 4R/3R ratio but also other factors such as post-transcriptional or translational modifications may play a role in the pathogenesis of specific neurodegeneration in PSP and CBD.