碱化修饰甲状腺素运载蛋白显著增强对淀粉样β蛋白聚集的抑制作用  

Basification modification of transthyretin significantly enhances inhibitory effect on amyloid-βprotein aggregation

作　　者：侯文起 孙彦 董晓燕 HOU Wenqi;SUN Yan;DONG Xiaoyan(School of Chemical Engineering and Technology,Key Laboratory of Systems Bioengineering(Ministry of Education),Tianjin University,Tianjin 300350,China)

机构地区：[1]天津大学化工学院系统生物工程教育部重点实验室,天津300350

出　　处：《化工学报》2023年第5期2100-2110,共11页CIESC Journal

基　　金：国家自然科学基金项目(21978207)。

摘　　要：阿尔茨海默症与淀粉样β蛋白(amyloid-βprotein,Aβ)的纤维化聚集有关,因此开发高效的抗Aβ聚集的抑制剂是防治阿尔茨海默症的策略之一。研究发现,甲状腺素运载蛋白(transthyretin,TTR)可通过疏水作用抑制Aβ单体之间的聚集,但抑制作用需要较高蛋白浓度(150μg·ml^(-1))。为了提高TTR抑制Aβ聚集的作用,本研究利用乙二胺修饰TTR表面的羧基,生成碱化甲状腺素运载蛋白(TTR-B),以增加其与带负电荷的Aβ之间的静电相互作用。研究表明,修饰度最高的TTR-B3(平均每分子TTR上38.9%的羧基被转换成氨基)对Aβ聚集的抑制能力显著提高,在较低的浓度下(15μg·ml-1)即可有效缓解Aβ对细胞的毒性(使细胞活性从78%提高至>90%),浓度仅为TTR的10%。与碱化人血清白蛋白(HSA-BF)相比,TTR-B3用量为HSA-BF的75%时即可使AD线虫延长相同的寿命,在HSA-BF用量的45%时即可完全清除AD线虫体内的Aβ斑块。结果表明TTR-B3是一种高效的Aβ聚集抑制剂。Alzheimer’s disease(AD)is considered to be closely associated with the fibrillar aggregation of amyloid-βprotein(Aβ).Therefore,development of efficient inhibitors against Aβfibrillization is one of the strategies to combat AD.Previous studies have found the inhibition effect of transthyretin(TTR)on Aβfibrillization through hydrophobic interactions,but it only showed high inhibitory potency at quite high concentrations(150μg·ml-1).To elevate the potency of TTR on inhibiting Aβaggregation,this work used the basification method by modifying TTR with ethylenediamine via its reaction with the carboxyl groups on the protein surface.The TTR basification could increase the electrostatic interactions between basified TTR(TTR-B)and the negatively charged Aβ.Studies have shown that TTR-B3 with the highest degree of modification(on average 38.9%of the carboxyl groups on TTR per molecule are converted to amino groups)has a significantly improved ability to inhibit Aβaggregation.The potency of TTR-B3 was much more efficient than native TTR.TTR-B3 alleviated the toxicity of Aβaggregates and increased the cultured cell viability from 78%to>90%at 15μg·ml^(-1),which was only 10%of native TTR.As compared to basified human serum albumin(HSA-BF),TTR-B3 also worked at significantly lower dosages.TTR B3 extended the same lifespan of AD nematodes at 75%of HSA-BF,and completely scavenged Aβplaques in AD nematodes at 45%of HSA-BF.The results indicated that TTR-B3 is a highly effective inhibitor of Aβaggregation.

关 键 词：阿尔茨海默症 蛋白质 淀粉样Β蛋白 甲状腺素运载蛋白 聚集 生物医学工程 

分 类 号：TQ460.1[化学工程—制药化工]