Institute of Bioanalysis, Coburg University of Applied Sciences, Coburg, Germany.
German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany.
Alzheimers Res Ther. 2022 Jan 21;14(1):15. doi: 10.1186/s13195-022-00959-z.
Alzheimer's disease (AD), the most common form of dementia, is a progressive neurodegenerative disorder that mainly affects older adults. One of the pathological hallmarks of AD is abnormally aggregated Tau protein that forms fibrillar deposits in the brain. In AD, Tau pathology correlates strongly with clinical symptoms, cognitive dysfunction, and neuronal death.
We aimed to develop novel therapeutic D-amino acid peptides as Tau fibrillization inhibitors. It has been previously demonstrated that D-amino acid peptides are protease stable and less immunogenic than L-peptides, and these characteristics may render them suitable for in vivo applications. Using a phage display procedure against wild type full-length Tau (Tau), we selected a novel Tau binding L-peptide and synthesized its D-amino acid version ISAD1 and its retro inversed form, ISAD1rev, respectively.
While ISAD1rev inhibited Tau aggregation only moderately, ISAD1 bound to Tau in the aggregation-prone PHF6 region and inhibited fibrillization of Tau, disease-associated mutant full-length Tau (Tau, Tau, Tau), and pro-aggregant repeat domain Tau mutant (Tau). ISAD1 and ISAD1rev induced the formation of large high molecular weight Tau and Tau oligomers that lack proper Thioflavin-positive β-sheet conformation even at lower concentrations. In silico modeling of ISAD1 Tau interaction at the PHF6 site revealed a binding mode similar to those known for other PHF6 binding peptides. Cell culture experiments demonstrated that ISAD1 and its inverse form are taken up by N2a-Tau cells efficiently and prevent cytotoxicity of externally added Tau fibrils as well as of internally expressed Tau.
ISAD1 and related peptides may be suitable for therapy development of AD by promoting off-pathway assembly of Tau, thus preventing its toxicity.
阿尔茨海默病（AD）是最常见的痴呆症形式，是一种进行性神经退行性疾病，主要影响老年人。AD 的病理标志之一是异常聚集的 Tau 蛋白，在大脑中形成纤维状沉积物。在 AD 中，Tau 病理学与临床症状、认知功能障碍和神经元死亡密切相关。
我们旨在开发新型治疗性 D-氨基酸肽作为 Tau 纤维形成抑制剂。先前已经证明，D-氨基酸肽比 L-肽稳定，免疫原性更低，这些特性可能使它们适合体内应用。我们使用针对野生型全长 Tau（Tau）的噬菌体展示程序，选择了一种新型 Tau 结合 L-肽，并分别合成了其 D-氨基酸版本 ISAD1 及其反向形式 ISAD1rev。
虽然 ISAD1rev 仅适度抑制 Tau 聚集，但 ISAD1 结合 Tau 在易聚集的 PHF6 区域并抑制 Tau、与疾病相关的突变全长 Tau（Tau、Tau、Tau）和促聚集重复结构域 Tau 突变体（Tau）的纤维形成。ISAD1 和 ISAD1rev 诱导形成大的高分子量 Tau 和 Tau 寡聚物，即使在较低浓度下，也缺乏适当的 Thioflavin 阳性 β-折叠构象。ISAD1 在 PHF6 位点与 Tau 的计算机建模揭示了一种与其他 PHF6 结合肽相似的结合模式。细胞培养实验表明，ISAD1 和其反向形式被 N2a-Tau 细胞有效摄取，并防止外加 Tau 纤维和内源性表达的 Tau 的细胞毒性。
ISAD1 和相关肽可能适合通过促进 Tau 的非途径组装来开发 AD 的治疗方法，从而防止其毒性。
