Abstract
Amyloid polymorphs have become one of the focal points of molecular studies of neurodegenerative diseases like Parkinson's disease. Due to their distinct biochemical properties and prion-like characteristics, insights into the molecular origin and stability of amyloid polymorphs over time are crucial for understanding the potential role of amyloid polymorphism in these diseases. Here, we systematically study the fibrillization of recombinantly produced human α-synuclein (αSyn) over an extended period of time to unravel the origin and temporal evolution of polymorphism. We follow morphological changes in the same fibril sample with atomic force microscopy over a period of 1 year. We show that wild-type (wt) αSyn fibrils undergo a slow maturation over time after reaching the plateau phase of aggregation (as detected in a Thioflavin-T fluorescence assay). This maturation, visualized by changes in the fibril periodicity over time, is absent in the disease mutant fibrils. The β-sheet content of the plateau phase and matured fibrils, obtained using Fourier transform infrared spectroscopy, is however similar for the αSyn protein sequences, suggesting that the morphological changes in wt αSyn fibrils are tertiary or quaternary in origin. Furthermore, results from a reversibility assay show that the plateau phase fibrils do not disassemble over time. Together, the observed changes in the periodicity distributions and stability of the fibrillar core over time point toward two distinct mechanisms that determine the morphology of wt αSyn fibrils: competitive growth between different polymorphs during the fibrillization phase followed by a process wherein fibrils undergo slow maturation or annealing.
Original language | English |
---|---|
Pages (from-to) | 538-547 |
Number of pages | 10 |
Journal | ACS Chemical Neuroscience |
Volume | 8 |
Issue number | 3 |
DOIs | |
Publication status | Published - 15 Mar 2017 |
Funding
This work is supported by NanoNextNL, a micro-and nanotechnology consortium of the Government of The Netherlands and 130 partners. We also acknowledge support from the Foundation for Fundamental Research on Matter (FOM), which is part of Netherlands Organization for Scientific Research (NWO). V.R. is Senior Research Associate for the F.R.S.-FNRS (Belgium) and acknowledges support from the F.R.S.-FNRS (PDR No. 70214.12) and the SAO-FRA (Grant No. 14025).
Funders | Funder number |
---|---|
SAO-FRA | 14025 |
Stichting voor Fundamenteel Onderzoek der Materie | |
Fonds De La Recherche Scientifique - FNRS | 70214.12 |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek |
Keywords
- Journal Article