title: Synergistic effects of negatively charged hydrophobic nanoparticles and (-)-epigallocatechin-3-gallate on inhibiting amyloid β-protein aggregation.
abstract: Fibrillogenesis of amyloid β-protein (Aβ) in human brain has been implicated as the main cause of Alzheimer's disease. A few small molecules from natural sources have been discovered for their inhibition effects on Aβ fibrillation, of which (-)-epigallocatechin-3-gallate (EGCG) is one of the most broadly investigated compounds for its potent inhibitory activity. However, in vivo applicability of the inhibitors is largely limited by their low transmembrane efficiency. Hence, it is of great significance to develop inhibition systems that function at low concentrations. In this work, a dual-inhibitor system containing EGCG and negatively charged polymeric nanoparticles (NP10), which was also demonstrated effective on the inhibition of Aβ aggregation, was developed and comprehensively studied by extensive biophysical and biological assays. It was found that the dual-inhibitor system at low concentrations was more effective on the inhibition and detoxification of Aβ (Aβ42and Aβ40) fibrillation than the additive effects of these two agents working individually. Namely, there was a synergistic effect of the two inhibitors. The synergism factor reached 1.25 with 5μM EGCG and 5μg/mL NP10. Kinetic studies with Aβ40revealed that the two inhibitors functioned in different Aβ assembling stages: NP10 mainly inhibited primary nucleation, while EGCG suppressed fibril elongation and changed the fibril structure to make it show less seeding activities in the secondary nucleation. NP10 might also help EGCG binding to Aβ, leading to its enhanced inhibitory effects on fibril elongation and secondary nucleation. The synergistic effect observed in the dual-inhibitor system offered new insight into the development of potent inhibitor systems against amyloid neurotoxicity.
authors.affiliation: Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Hongchen
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Linling
authors.initials: L
authors.lastname: Yu
authors.affiliation: Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Dong
authors.affiliation: Department of Biochemical Engineering and Key Laboratory of Systems Bioengineering of the Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China. Electronic address: ysun@tju.edu.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Sun
mesh_terms: D016229:Amyloid beta-Peptides / Q000037:antagonists & inhibitors* / Q000737:chemistry; D002392:Catechin / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D053758:Nanoparticles / Q000737:chemistry*; D066329:Protein Aggregates / Q000187:drug effects*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
chemical_list: D016229:Amyloid beta-Peptides; D066329:Protein Aggregates; D002392:Catechin; C045651:epigallocatechin gallate
keywords: (−)-Epigallocatechin-3-gallate; Aggregation; Amyloid β-protein; Inhibition; Polymeric nanoparticle