Department of Laboratory Medicine, Shimane University Faculty of Medicine, 89-1 Enya Cho, Izumo 693-8501, Japan.
Department of Neurology, Shimane University Faculty of Medicine, 89-1 Enya Cho, Izumo 693-8501, Japan.
Int J Mol Sci. 2024 Aug 16;25(16):8931. doi: 10.3390/ijms25168931.
Amyloid β peptide (Aβ) aggregation and deposition are considered the main causes of Alzheimer's disease. In a previous study, we demonstrated that anionic Zn-phthalocyanine (ZnPc) can interact with the Aβ peptide and inhibit the fibril-formation process. However, due to the inability of anionic ZnPc to cross the intact blood-brain barrier, we decided to explore the interaction of cationic methylated Zn-phthalocyanine (cZnPc) with the peptide. Using a ThT fluorescence assay, we observed that cZnPc dose-dependently and time-dependently inhibited Aβ fibril levels under in vitro fibril-formation conditions. Electron microscopy revealed that it caused Aβ peptides to form small aggregates. Western blotting and dot immunoblot oligomer experiments demonstrated that cZnPc increased rather than decreased the levels of oligomers from the very early stages of incubation. A binding assay confirmed that cZnPc could bind with the peptide. Docking simulations indicated that the oligomer species of Aβ had a higher ability to interact with cZnPc. ANS fluorescence assay results indicated that cZnPc did not affect the hydrophobicity of the peptide. However, cZnPc significantly increased intrinsic tyrosine fluorescence of the peptide after 8 h of incubation in fibril-formation conditions. Importantly, cell culture experiments demonstrated that cZnPc did not exhibit any toxicity up to a concentration of 10 µM. Instead, it protected a neuronal cell line from Aβ-induced toxicity. Thus, our results suggest that cZnPc can affect the aggregation process of Aβ, rendering it non-toxic, which could be crucial for the therapy of Alzheimer's disease.
淀粉样 β 肽 (Aβ) 的聚集和沉积被认为是阿尔茨海默病的主要原因。在之前的研究中，我们证明了阴离子锌酞菁 (ZnPc) 可以与 Aβ 肽相互作用并抑制纤维形成过程。然而，由于阴离子 ZnPc 无法穿过完整的血脑屏障，我们决定探索阳离子甲基化锌酞菁 (cZnPc) 与肽的相互作用。使用 ThT 荧光测定法，我们观察到 cZnPc 在体外纤维形成条件下剂量依赖性和时间依赖性地抑制 Aβ 纤维水平。电子显微镜显示它导致 Aβ 肽形成小聚集体。Western blot 和斑点免疫印迹寡聚物实验表明，cZnPc 在孵育的早期阶段增加而不是减少寡聚物的水平。结合测定证实 cZnPc 可以与肽结合。对接模拟表明 Aβ 的寡聚物具有与 cZnPc 更高的相互作用能力。ANS 荧光测定结果表明，cZnPc 不会影响肽的疏水性。然而，在纤维形成条件下孵育 8 小时后，cZnPc 显著增加了肽的固有酪氨酸荧光。重要的是，细胞培养实验表明，cZnPc 在高达 10 µM 的浓度下没有表现出任何毒性。相反，它可以保护神经元细胞系免受 Aβ 诱导的毒性。因此，我们的结果表明，cZnPc 可以影响 Aβ 的聚集过程，使其无毒，这对于阿尔茨海默病的治疗可能至关重要。
