以逆相微胞製備類澱粉多肽分子寡聚物之研究

Oligomeric aggregates of beta-amyloid peptides confined in reverse micelles

鄭友勝(Yu-Sheng Cheng)

指導教授 ： 陳振中

國立臺灣大學/理學院/化學研究所/碩士(2016年)

https://doi.org/10.6342/NTU201600752

摘要

Beta-amyloid peptides (Aβ)是用來研究阿茲海默症病徵的一個重要因素。現今，已經有很多文獻利用不同方法來了解Aβ 胜肽的聚合過程和結構樣貌。在Aβ 胜肽的聚合過程中，寡聚物被認為與單體和纖維相比，是神經毒性較高的物種。由於寡聚物具有多態性(polymorphism)，因此較難以研究寡聚物的結構樣貌。
在本實驗中，我們利用逆相微胞去模擬 Aβ 在擁擠的生物系統中寡聚化的
過程。利用Aerosol-OT (AOT, sodium bis(2-ethylexyl) sulfosuccinate)界面活性劑來製備逆相微胞系統，並選擇粒徑大小為33 nm(W0 為70)的逆相微胞來包覆單體，藉由逆相微胞碰撞性質，使其水相內的物質交換聚合而形成逆相微胞寡聚物(RM-Aβ oligomer)。利用ThT 螢光光譜和OMAB 斑點印跡法觀測Aβ 的聚合情形。我們也在不同培養天數下打破逆相微胞，並利用ThT 螢光監測25°C 静置培養下水相Aβ 的聚集情形，我們發現其聚集纖維的速度很快，是AOT 微胞促進纖維化，或是寡聚物作為一個核種(seed)，使聚合過程中所需跨越的能障較
低，而快速聚合成纖維，這點仍有待更進一步的實驗證實。

關鍵字

阿茲海默症 ； 類澱粉多肽分子 ； 逆相微胞

並列摘要

Beta-amyloid peptides (Aβ) are widely considered as the key factor in the investigation of Alzheimer's disease (AD). The formation and accumulation of the peptides have been studied for a long time. According to recent research, Aβ oligomers may be a more relevant therapeutic target than other species such as fibrillar aggregates.
To understand the process of Aβ oligomerization in this study, we employ reverse micelles (RMs) to simulate the crowded biological environment, in which the structure and kinetics of Aβ are studied. In water-in-oil microemulsion, water droplets are dispersed in isooctane surrounded by anionic surfactant, Aerosol-OT (AOT, sodium bis(2-ethylexyl) sulfosuccinate). The size of RM is related to water loading (W0) parameter, which is the ratio of water molecules to surfactant molecules (W0 = [H2O] / [surfactant]). We encapsulate Aβ in RMs (W0 = 70) with 33 nm in hydrodynamic diameter measured by dynamic light scattering. To monitor and analyze the structural properties of Aβ, we use the OMAB dot blot and fluorescent dye Thioflavin-T (ThT) which is a powerful tool for detecting amyloid peptide aggregation. Reverse micelles provide a confined space for the studies of the aggregation state of peptides. In addition, we also disrupt the reverse micelle in different incubation periods and use ThT fluorescence to keep track Aβ of incubating quiescently in water phase at 25°C. We find that it becomes into fibril quickly. However, further investigation are needed to understand either AOT micelles or oligomeric seeds promote aggregation.

並列關鍵字

AD ； beta-amyloid ； Aβ ； Aerosol-OT ； AOT ； Reverse micelles ； RMs ； Thioflavin-T ； ThT

參考文獻

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