期刊
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
卷 464, 期 1, 页码 336-341出版社
ACADEMIC PRESS INC ELSEVIER SCIENCE
DOI: 10.1016/j.bbrc.2015.06.154
关键词
Alpha-synuclein; Oligomers; Aggregation; Amyloid; Oxidative stress; 4-Hydroxy-2-nonenal; 4-Oxo-2-nonenal; Parkinson's disease; Dementia with Lewy bodies
资金
- China Scholarship Council (CSC)
- Uppsala Berzelii Technology Center for Neurodiagnostics
- Swedish Parkinson Foundation
- Swedish Alzheimer Foundation
- Swedish Brain Foundation
- Stohne's Foundation
- Ahlen Foundation
- Marianne and Marcus Wallenberg Foundation
- Lennart and Christina Kalen
The oxidative stress-related reactive aldehydes 4-hydroxy-2-nonenal (HNE) and 4-oxo-2-nonenal (ONE) have been shown to promote formation of alpha-synuclein oligomers in vitro. However, the changes in secondary structure of alpha-synuclein and the kinetics of the oligomerization process are not known and were the focus of this study. Size exclusion chromatography showed that after 1 h of incubation, HNE induced the formation of an oligomeric alpha-synuclein peak with a molecular weight of about similar to 2000 kDa, which coincided with a decreasing similar to 50 kDa monomeric peak. With prolonged incubation (up to 24 h) the oligomeric peak became the dominating molecular species. In contrast, in the presence of ONE, a similar to 2000 oligomeric peak was exclusively observed after 15 min of incubation and this peak remained constant with prolonged incubation. Western blot analysis of HNE-induced alpha-synuclein oligomers showed the presence of monomers (15 kDa), SDS-resistant low molecular (30-160 kDa) and high molecular weight oligomers (>= 260 kDa), indicating that the oligomers consisted of both covalent and non-covalent protein. In contrast, ONE-induced alpha-synuclein oligomers only migrated as covalent cross-linked high molecular-weight material (>= 300 kDa). Both circular dichroism (CD) and Attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy showed that the formation of HNE- and ONE-induced oligomers coincided with a spectral change from random coil to beta-sheet. However, ONE-induced alpha-synuclein oligomers exhibited a slightly higher degree of beta-sheet. Taken together, our results indicate that both HNE and ONE induce a change from random coil to beta-sheet structure that coincides with the formation of alpha-synuclein oligomers; albeit through different kinetic pathways depending on the degree of cross-linking. (C) 2015 Elsevier Inc. All rights reserved.
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