Genetic variation at the PTK2B locus encoding the protein Pyk2 influences Alzheimer’s disease risk. Neurons express Pyk2 and the protein is required for Amyloid-β (Aβ) peptide driven deficits of synaptic function and memory in mouse models, but Pyk2 deletion has minimal effect on neuro-inflammation. Previous in vitro data suggested that Pyk2 activity might enhance GSK3β-dependent Tau phosphorylation and be required for tauopathy. Here, we examine the influence of Pyk2 on Tau phosphorylation and associated pathology. The effect of Pyk2 on Tau phosphorylation was examined in cultured Hek cells through protein over-expression and in iPSC-derived human neurons through pharmacological Pyk2 inhibition. PS19 mice overexpressing the P301S mutant of human Tau were employed as an in vivo model of tauopathy. Phenotypes of PS19 mice with a targeted deletion of Pyk2 expression were compared with PS19 mice with intact Pyk2 expression. Phenotypes examined included Tau phosphorylation, Tau accumulation, synapse loss, gliosis, proteomic profiling and behavior. Over-expression experiments from Hek293T cells indicated that Pyk2 contributed to Tau phosphorylation, while iPSC-derived human neuronal cultures with endogenous protein levels supported the opposite conclusion. In vivo, multiple phenotypes of PS19 were exacerbated by Pyk2 deletion. In Pyk2-null PS19 mice, Tau phosphorylation and accumulation increased, mouse survival decreased, spatial memory was impaired and hippocampal C1q deposition increased relative to PS19 littermate controls. Proteomic profiles of Pyk2-null mouse brain revealed that several protein kinases known to interact with Tau are regulated by Pyk2. Endogenous Pyk2 suppresses LKB1 and p38 MAPK activity, validating one potential pathway contributing to increased Tau pathology. The absence of Pyk2 results in greater mutant Tau-dependent phenotypes in PS19 mice, in part via increased LKB1 and MAPK activity. These data suggest that in AD, while Pyk2 activity mediates Aβ-driven deficits, Pyk2 suppresses Tau-related phenotypes.

中文翻译：

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阿尔茨海默病风险基因产物 Pyk2 抑制 tau 磷酸化和 tau 病变的表型效应

编码蛋白质 Pyk2 的 PTK2B 基因座的遗传变异会影响阿尔茨海默病的风险。神经元表达 Pyk2，并且该蛋白是小鼠模型中淀粉样蛋白-β (Aβ) 肽驱动的突触功能和记忆缺陷所必需的，但 Pyk2 缺失对神经炎症的影响很小。先前的体外数据表明，Pyk2 活性可能增强 GSK3β 依赖性 Tau 磷酸化，并且是 tau 病变所必需的。在这里，我们检查了 Pyk2 对 Tau 磷酸化和相关病理学的影响。Pyk2 对 Tau 磷酸化的影响通过蛋白质过表达在培养的 Hek 细胞中和通过药理学 Pyk2 抑制在 iPSC 衍生的人类神经元中进行了检查。过表达人 Tau 的 P301S 突变体的 PS19 小鼠被用作 tauopathy 的体内模型。将具有靶向缺失 Pyk2 表达的 PS19 小鼠的表型与具有完整 Pyk2 表达的 PS19 小鼠进行比较。检查的表型包括 Tau 磷酸化、Tau 积累、突触丢失、神经胶质增生、蛋白质组学分析和行为。Hek293T 细胞的过表达实验表明 Pyk2 有助于 Tau 磷酸化，而具有内源性蛋白水平的 iPSC 衍生的人类神经元培养物支持相反的结论。在体内，Pyk2 缺失加剧了 PS19 的多种表型。在 Pyk2-null PS19 小鼠中，Tau 磷酸化和积累增加，小鼠存活率下降，空间记忆受损，海马 C1q 沉积相对于 PS19 同窝小鼠增加。Pyk2-null 小鼠大脑的蛋白质组学分析表明，已知与 Tau 相互作用的几种蛋白激酶受 Pyk2 的调节。内源性 Pyk2 抑制 LKB1 和 p38 MAPK 活性，验证了导致 Tau 病理学增加的一种潜在途径。Pyk2 的缺失导致 PS19 小鼠出现更大的突变 Tau 依赖性表型，部分原因是 LKB1 和 MAPK 活性增加。这些数据表明，在 AD 中，虽然 Pyk2 活性介导 Aβ 驱动的缺陷，但 Pyk2 抑制 Tau 相关表型。