Inhibition of α‐Synuclein Amyloid Fibril Elongation by Blocking Fibril Ends

Abstract

Misfolding of the protein α-synuclein (αSyn) into amyloid fibrils plays a central role in the development of Parkinson's disease. Most approaches for the inhibition of αSyn fibril formation are based on stabilizing the native monomeric form of the protein or destabilizing the fibrillized misfolded form. They require high concentrations of inhibitor and therefore cannot be easily used for therapies. In this work, we designed an inhibitor (Inh-β) that selectively binds the growing ends of αSyn fibrils and creates steric hindrance for the binding of monomeric αSyn. This approach permits the inhibition of fibril formation at Inh-β concentrations (IC =850 nm) much lower than the concentration of monomeric αSyn. We studied its kinetic mechanism in vitro and identified the reactions that limit inhibition efficiency. It is shown that blocking of αSyn fibril ends is an effective approach to inhibiting fibril growth and provides insights for the development of effective inhibitors of αSyn aggregation.

Differential Modulation of the Aggregation of N‐Terminal Truncated Aβ using Cucurbiturils

“…By means of global fitting (Figure , solid lines), we could see that the fibril‐end inhibition mechanism indeed agreed well with all experimental data. A similar mechanism has been reported by Shvadchak et al., who designed an inhibitor that selectively bound to the growing ends of α‐synuclein fibrils and created steric hindrance for binding of monomeric α‐synuclein …”

“…As imilarm echanism has been reported by Shvadchak et al,who designed an inhibitor that selectively bound to the growing ends of a-synuclein fibrils and created steric hindrance for binding of monomeric a-synuclein. [25] With the help of chemical kinetics analysis( see Experimental Sectionf or details), we found the binding rate k b for CB [7] with Ab 4-40 was about five times fastert han CB [7] with Ab 1-40 (2:0 Â 10 À2 mM À1 min À1 versus 3:7 Â 10 À3 mM À1 min À1 ); whereas it became more than forty times faster for CB [8] with Ab 4-40 than CB [8] with Ab 1-40 (0:10 mM À1 min À1 versus 2:5 Â 10 À3 mM À1 min À1 ). These facts hinted that both CB [7] and CB [8] had ah igher binding affinity to Ab 4-40 than Ab 1-40 ,w hich was in ag ood agreement with the ITC data in Figure 2.…”

The growth of amyloid fibrils: rates and mechanisms

“…[87]. Suffice it to say that amyloid fibril growth can be inhibited by adding an inhibitor species to the solution that either interacts with the fibril end [88,89] or with the monomeric protein [90]. However, not every molecule that binds to the monomer will be an efficient inhibitor of fibril growth.…”

Amyloidophilic Molecule Interactions on the Surface of Insulin Fibrils: Cooperative Binding and Fluorescence Quenching

“…Potential drugs that directly influence amyloid formation or dissociation have to, in one way or another, interact with either the native state protein (stabilizing the native state or changing the aggregation’s path to non-fibrillar species 29,30) or with the fibril (causing its dissociation or preventing it from incorporating native proteins 31,32) . In cases when it interacts with fibrils, it could act in a similar way as CR did with ThT in the previously mentioned reports.…”