Mocanu Maria-Magdalena, Nissen Astrid, Eckermann Katrin, Khlistunova Inna, Biernat Jacek, Drexler Dagmar, Petrova Olga, Schönig Kai, Bujard Hermann, Mandelkow Eckhard, Zhou Lepu, Rune Gabriele, Mandelkow Eva-Maria
Max Planck Unit for Structural Molecular Biology, 22607 Hamburg, Germany.
J Neurosci. 2008 Jan 16;28(3):737-48. doi: 10.1523/JNEUROSCI.2824-07.2008.
We describe two new transgenic mouse lines for studying pathological changes of Tau protein related to Alzheimer's disease. They are based on the regulatable expression of the four-repeat domain of human Tau carrying the FTDP17 (frontotemporal dementia and parkinsonism linked to chromosome 17) mutation deltaK280 (Tau(RD)/deltaK280), or the deltaK280 plus two proline mutations in the hexapeptide motifs (Tau(RD)/deltaK280/I277P/I308P). The deltaK280 mutation accelerates aggregation ("proaggregation mutant"), whereas the proline mutations inhibit Tau aggregation in vitro and in cell models ("antiaggregation mutant"). The inducible transgene expression was driven by the forebrain-specific CaMKIIalpha (calcium/calmodulin-dependent protein kinase IIalpha) promoter. The proaggregation mutant leads to Tau aggregates and tangles as early as 2-3 months after gene expression, even at low expression (70% of endogenous mouse Tau). The antiaggregation mutant does not aggregate even after 22 months of gene expression. Both mutants show missorting of Tau in the somatodendritic compartment and hyperphosphorylation in the repeat domain [KXGS motifs, targets of the kinase MARK (microtubule affinity regulating kinase)]. This indicates that these changes are related to Tau expression rather than aggregation. The proaggregation mutant causes astrogliosis, loss of synapses and neurons from 5 months of gene expression onward, arguing that Tau toxicity is related to aggregation. Remarkably, the human proaggregation mutant Tau(RD) coaggregates with mouse Tau, coupled with missorting and hyperphosphorylation at multiple sites. When expression of proaggregation Tau(RD) is switched off, soluble and aggregated exogenous Tau(RD) disappears within 1.5 months. However, tangles of mouse Tau, hyperphosphorylation, and missorting remain, suggesting an extended lifetime of aggregated wild-type Tau once a pathological conformation and aggregation is induced by a proaggregation Tau species.
我们描述了两种用于研究与阿尔茨海默病相关的 Tau 蛋白病理变化的新型转基因小鼠品系。它们基于携带 FTDP17（与 17 号染色体连锁的额颞叶痴呆和帕金森综合征）突变 deltaK280 的人 Tau 四重复结构域的可调节表达（Tau(RD)/deltaK280），或 deltaK280 加上六肽基序中的两个脯氨酸突变（Tau(RD)/deltaK280/I277P/I308P）。deltaK280 突变加速聚集（“促聚集突变体”），而脯氨酸突变在体外和细胞模型中抑制 Tau 聚集（“抗聚集突变体”）。诱导型转基因表达由前脑特异性 CaMKIIalpha（钙/钙调蛋白依赖性蛋白激酶 IIalpha）启动子驱动。促聚集突变体在基因表达后 2 - 3 个月就会导致 Tau 聚集物和缠结，即使在低表达水平（内源性小鼠 Tau 的 70%）时也是如此。抗聚集突变体即使在基因表达 22 个月后也不会聚集。两种突变体在树突状细胞体区域均表现出 Tau 分选错误以及重复结构域（[KXGS 基序，激酶 MARK（微管亲和力调节激酶）的作用靶点]）的过度磷酸化。这表明这些变化与 Tau 表达而非聚集有关。促聚集突变体从基因表达 5 个月起就会导致星形胶质细胞增生、突触和神经元丧失，这表明 Tau 毒性与聚集有关。值得注意的是，人类促聚集突变体 Tau(RD)与小鼠 Tau 共聚集，并伴有多个位点的分选错误和过度磷酸化。当促聚集 Tau(RD)的表达关闭时，可溶性和聚集的外源性 Tau(RD)在 1.5 个月内消失。然而，小鼠 Tau 的缠结、过度磷酸化和分选错误仍然存在，这表明一旦由促聚集 Tau 物种诱导出病理构象和聚集，聚集的野生型 Tau 就会有延长的寿命。
