Department of Chemistry, Indian Institute of Technology Delhi, New Delhi 110016, India.
ACS Chem Neurosci. 2020 Apr 15;11(8):1129-1138. doi: 10.1021/acschemneuro.9b00677. Epub 2020 Apr 6.
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that has been associated with the deposition of aggregates of superoxide dismutase 1 (SOD1). Effective therapeutics against SOD1 fibrillation is still an area of active research. Herein, we demonstrate the potential of two naturally occurring flavonoids (quercetin and baicalein) to inhibit fibrillation of wild-type SOD1 with the aid of a series of biophysical techniques. Our seeding experiments reveal that both of these flavonoids significantly affect the fibril elongation. Interestingly, our ThT binding assay, TEM, and SDS-PAGE experiments suggest that these flavonoids also disintegrate the fibrils into shorter fragments but do not completely depolymerize them into monomers. Binding parameters obtained from the analysis of UV-vis spectra suggest that these flavonoids bind moderately to native SOD1 dimer and have different binding sites. Docking of these flavonoids with a non-native monomer, non-native trimer, and oligomer derived from the 11-residue segment of SOD1 indicates that both quercetin and baicalein can bind to these species and thus can arrest the elongation of fibrils by blocking the fibrillar core regions on the intermediate species formed during aggregation of SOD1. MTT assay data revealed that both the flavonoids reduced the cytotoxicity of SOD1 fibrils. Experimental data also show the antiamyloidogenic potential of both flavonoids against A4V SOD1 mutant fibrillation. Thus, our findings may provide a direction for designing effective therapeutic agents against ALS which can act as promising antiamyloidogenic and fibril destabilizing agents.
肌萎缩侧索硬化症（ALS）是一种致命的神经退行性疾病，与超氧化物歧化酶 1（SOD1）的聚集物沉积有关。针对 SOD1 纤维形成的有效治疗方法仍然是一个活跃的研究领域。在此，我们利用一系列生物物理技术证明了两种天然存在的黄酮类化合物（槲皮素和黄芩素）抑制野生型 SOD1 纤维形成的潜力。我们的接种实验表明，这两种黄酮类化合物都能显著影响纤维的伸长。有趣的是，我们的 ThT 结合实验、TEM 和 SDS-PAGE 实验表明，这些黄酮类化合物也能将纤维分解成更短的片段，但不能将其完全解聚成单体。从紫外可见光谱分析得到的结合参数表明，这些黄酮类化合物适度结合天然 SOD1 二聚体，并具有不同的结合位点。这些黄酮类化合物与非天然单体、非天然三聚体和来自 SOD1 的 11 个残基片段的低聚物的对接表明，槲皮素和黄芩素都可以与这些物质结合，从而通过阻止 SOD1 聚集过程中形成的中间产物的纤维核心区域来阻止纤维的伸长。MTT 实验数据表明，两种黄酮类化合物都能降低 SOD1 纤维的细胞毒性。实验数据还显示了这两种黄酮类化合物对 A4V SOD1 突变体纤维形成的抗淀粉样变性潜力。因此，我们的研究结果可能为设计针对 ALS 的有效治疗药物提供一个方向，这些药物可以作为有前途的抗淀粉样变性和纤维不稳定的药物。
