Department of Biotechnology, St. Xavier's College, Kolkata, India.
Department of Chemistry & Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA.
Protein Pept Lett. 2022;29(11):993-1005. doi: 10.2174/0929866529666220905112156.
Alzheimer's disease (AD) is characterized by the aggregation of Tau protein and Amyloid-β peptides (Aβ 1-40 and Aβ 1-42). A loss of ribosomal population is also observed in the neurons in affected regions of AD. Our studies demonstrated that in vitro aggregation of amyloid forming proteins, Aβ peptides and Tau protein variants (AFPs), in the vicinity of yeast 80S ribosome can induce co-aggregation of ribosomal components.
In this study, the ability of minute quantities of AFP-ribosome co-aggregates to seed the aggregation of a large excess of untreated 80S ribosomes was explored.
The AFPs were purified using ion-exchange chromatography. Seeded aggregation of ribosomes in the presence of minute quantities of ribosome-protein co-aggregates or ribosomal components was studied using agarose gel electrophoretic and SDS-PAGE analysis of the pellets and Sucrose Density Gradient centrifugation of the supernatant obtained after centrifugation of the aggregation reaction mixture.
Our studies, therefore, demonstrate that minute quantities of AFP-80S co-aggregate have significant seeding potential and could lead to aggregation of a large excess of fresh 80S ribosomes and this seeding ability is sustained over multiple cycles of ribosome aggregation. The aggregation propensity of ribosomal components alone could contribute towards the seeding of ribosome aggregation.
The ability of minute quantities of AFP-80S co-aggregates to seed the aggregation of a large excess of fresh 80S ribosomes would result in the loss of global ribosomal population in Alzheimer's disease afflicted neurons. Hence, subject to further validation by in vivo studies, our in vitro studies indicate a significant mode of toxicity of amyloid aggregates that might be important in Alzheimer's disease pathology.
阿尔茨海默病（AD）的特征是 Tau 蛋白和淀粉样β肽（Aβ1-40 和 Aβ1-42）的聚集。在受 AD 影响的区域的神经元中，核糖体群体也会减少。我们的研究表明，在体外，淀粉样形成蛋白、Aβ 肽和 Tau 蛋白变体（AFPs）在酵母 80S 核糖体附近的聚集，会诱导核糖体成分的共聚集。
在这项研究中，研究了微量 AFP-核糖体共聚集物诱导大量未处理的 80S 核糖体聚集的能力。
使用离子交换层析法纯化 AFP。使用琼脂糖凝胶电泳和 SDS-PAGE 分析沉淀以及离心聚集反应混合物后获得的上清液的蔗糖密度梯度离心，研究了在微量核糖体-蛋白共聚集物或核糖体成分存在下，核糖体的种子聚集。
因此，我们的研究表明，微量的 AFP-80S 共聚集物具有显著的种子潜力，可以导致大量新鲜的 80S 核糖体的聚集，并且这种种子能力可以在多个核糖体聚集周期中持续存在。单独的核糖体成分的聚集倾向可能有助于核糖体聚集的种子化。
微量 AFP-80S 共聚集物诱导大量新鲜 80S 核糖体聚集的能力将导致受 AD 影响的神经元中全局核糖体群体的丧失。因此，在通过体内研究进一步验证之前，我们的体外研究表明，淀粉样体聚集具有显著的毒性模式，这可能对阿尔茨海默病病理学很重要。
