In the present study, a cell penetrating peptide (CPP)-amyloid conjugate was prepared (T-peptide), where the amyloid-forming sequence was homologous to a nucleating sequence from human Tau protein (³⁰⁶VQIVYK³¹¹). Kinetic and biophysical studies showed the peptide formed long-lived oligomers which were taken up by endocytosis and localized in perinuclear vesicles and in the cytoplasm of murine hippocampal neuroblastoma cells and human HeLa cells. Thioflavin S (ThS) staining of amyloid colocalized with pathological phosphorylated Tau, suggesting that the peptide was able to seed endogenous wild-type Tau. Subsequent experiments showed that aggregates present in the lysosomes mediated lysosome membrane permeability (LMP). We observed a decrease in total Tau, irrespective of phosphorylation state, consistent with Tau fragmentation by lysosomal proteases. We found cytotoxicity of T-peptide could be abrogated by inhibitors of lysosomal hydrolases and caspases, consistent with a model where Tau fragments processed by the lysosome leak into the cytoplasm and induce toxicity in subsequent downstream steps. It is our hope that the T-peptide system may prove amenable to the evaluation of small molecule inhibitors of cytotoxicity, especially those which target either Tau aggregation or the lysosomal/autophagy system.

中文翻译：

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细胞渗透性Tau相关肽诱导的Tauopathy的新型细胞模型。

在本研究中，制备了一种细胞穿透肽（CPP）-淀粉样蛋白偶联物（T-肽），其中淀粉样蛋白形成序列与人Tau蛋白的核化序列同源（³⁰⁶ VQIVYK ³¹¹）。动力学和生物物理研究表明，该肽形成了长寿命的寡聚体，这些寡聚体被内吞作用吸收并定位在鼠的海泡囊泡以及鼠海马神经母细胞瘤细胞和人HeLa细胞的细胞质中。淀粉的硫黄素S（ThS）染色与病理磷酸化的Tau共定位，表明该肽能够播种内源性野生型Tau。随后的实验表明，溶酶体中存在的聚集体介导了溶酶体膜通透性（LMP）。我们观察到总Tau的降低，而与磷酸化状态无关，与溶酶体蛋白酶的Tau片段化相一致。我们发现溶酶体水解酶和胱天蛋白酶的抑制剂可以消除T肽的细胞毒性，与溶酶体加工的Tau片段泄漏到细胞质并在随后的下游步骤中诱导毒性的模型相符。我们希望，T肽系统可以证明适合评估细胞毒性的小分子抑制剂，尤其是针对Tau聚集或溶酶体/自噬系统的小分子抑制剂。