Insight into the Inhibition Effect of Acidulated Serum Albumin on Amyloid 尾-Protein Fibrillogenesis and Cytotoxicity
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- 作者：Baolong Xie ; Xi Li ; Xiao-Yan Dong ; Yan Sun
- 刊名：Langmuir
- 出版年：2014
- 出版时间：August 19, 2014
- 年：2014
- 卷：30
- 期：32
- 页码：9789-9796
- 全文大小：400K
- ISSN：1520-5827
文摘
Alzheimer鈥檚 disease (AD) is the most prevalent form of dementia, and aggregation of amyloid 尾-proteins (A尾) into soluble oligomers and fibrils has been implicated in the pathogenesis of AD. Herein we developed acidulated serum albumin for the inhibition of A尾42 fibrillogenesis. Bovine serum albumin (BSA) was modified with diglycolic anhydride, leading to the coupling of 14.5 more negative charges (carboxyl groups) on average on each protein surface. The acidulated BSA (A-BSA) was characterized and confirmed to keep the tertiary structure and stability of BSA. Extensive biophysical and biological analyses showed that A-BSA significantly inhibited A尾42 fibrillogenesis and mitigated amyloid cytotoxicity. As compared to the A尾42-treated group (cell viability, 50%), the cell viability increased to 88% by the addition of equimolar A-BSA. The inhibitory effect was remarkably higher than that of BSA at the same concentration. On the basis of the experimental findings, a mechanistic model was proposed. The model considers that A尾42 is bound to the A-BSA surface by hydrophobic interactions, but the widely distributed negative charges on the A-BSA surface give rise to electrostatic repulsions to the bound A尾42 that is also negatively charged. The two well-balanced opposite forces make A尾42 adopt extended conformations instead of the 尾-sheet structure that is necessary for the on-pathway fibrillogenesis, even when the protein is released off the surface. Thus, A-BSA greatly slows down the fibrillation and changes the fibrillogenesis pathway, leading to the formation of less toxic aggregates. The findings and the mechanistic model offer new insights into the development of more potent inhibitors of A尾 fibrillogenesis and cytotoxicity.