4-Hydroxy-2-nonenal (HNE) Modification of Histidine 50 Affects the Biophysical Properties of α-Synuclein: Implications for Parkinson's Disease

Loading...
Thumbnail Image
Penn collection
Master of Chemical Sciences Capstone Projects
Degree type
Discipline
Subject
neurodegenerative disease
alpha-synuclein
protein misfolding
parkinson's disease
biochemistry
chemical biology
Biochemistry
Chemistry
Molecular Biology
Funder
Grant number
Copyright date
Distributor
Related resources
Contributor
Abstract

Parkinson’s disease (PD) is a neurodegenerative disease that actively furthers the degeneration of dopaminergic neurons in substantia nigra and is characterized by the accumulation of α-synuclein (αS) in Lewy Bodies. During oxidative stress, increased levels of free radicals induce lipid peroxidation of polyunsaturated fatty acids, leading to the generation of reactive aldehydes within the body. Specifically, 4-hydroxy-2-nonenal (HNE) is known to be a lipid peroxidation product that can post-translationally modify αS, especially histidine 50 (H50). While studies have focused on the toxic effects of HNE-modified αS oligomers, no studies have determined how the site-specific H50-HNE interaction affects the biological and physical properties of αS. The purpose of this study is to identify how the site-specific modification of H50-HNE contributes to the pathogenesis of αS. To accomplish this, αS monomers were reacted with HNE, and the site-specific modification of H50 by HNE was confirmed using trypsin digest. These adducts were used to study its effect on αS aggregation, lipid binding, and cell uptake. Congo Red assay, incorporation assay, and dynamic light scattering (DLS) experiments showed that the H50-HNE modification was enough to significantly hinder the aggregation of αS, leading to a slower aggregation kinetics and smaller aggregate sizes. Moreover, the H50-HNE modification of αS induced a two-fold increase in lipid binding affinity, which may play a significant role in neurotransmitter release or synaptic vesicle integrity. Lastly, although both αS WT and HNE-modified monomers showed low levels of uptake in SH-SY5Y cells, where they were internalized by the lysosomal/endosomal system, the accuracy of these results is unconclusive and needs be addressed in future studies. The data collectively demonstrate that H50-HNE modification alone can significantly affect the biophysical properties of αS.

Advisor
Date Range for Data Collection (Start Date)
Date Range for Data Collection (End Date)
Digital Object Identifier
Series name and number
Publication date
2021-01-08
Volume number
Issue number
Publisher
Publisher DOI
Journal Issue
Comments
Recommended citation
Collection