Aggregation of α-synuclein in primary neuron models of Parkinson’s disease
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Biotechnology (MPBIO), MSc
Publicerad
2024
Författare
Allgén, Elin
Borg, Olivia
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Parkinson’s disease (PD) is the second most prevalent neurodegenerative disorder, characterized by the progressive loss of dopaminergic neurons, leading to impaired motor function. In PD pathology, substantial evidence suggest that the neuronal loss is caused by the protein α-synuclein (α-syn) which aggregates into insoluble amyloid fibrils Mutations in the SNCA gene, encoding α-syn, can accelerate disease progression by enhancing the protein’s propensity to aggregate. Synthetic amyloid fibrils called pre-formed fibrils (PPFs) have recently been developed as a valuable tool for studying disease progression in vitro, by effectively induce endogenous aggregation in cells. In this project, five α-synuclein variants were studied: wild-type (WT) and pathological mutants A30P, E46K, H50Q, and A53T. The study aimed to characterize the biophysical properties of PFFs, identify differences among the variants, and assess their ability to induce endogenous α-syn aggregation and potential neurotoxicity. PFFs were generated and characterized using atomic force microscopy (AFM), circular dichroism (CD), and Thioflavin T fluorescence spectroscopy (ThT Assay). Cellular assays with primary cortical cultures from rat and mouse were then employed to evaluate cellular health, viability, and α-syn aggregation.
This thesis demonstrated that within a given experiment PFFs could be generated and sonicated in a reproducible manner. Biophysical characterization revealed differences among the α-syn variants, including distinct morphologies, variations in monomer conversion to PFFs, and differences in fluorescence intensity and molar ellipticity. Furthermore, all α-syn variants induced endogenous aggregation in both cell models, with distinct aggregation patterns observed across variants and between models. E46K PFFs caused the highest level of aggregation in the mouse model without affecting cellular health, whereas A53T PFFs led to the highest aggregation in the rat model and impaired dendritic networks. H50Q induced minimal aggregation in both models, but negatively affected dendritic networks, suggesting potential neurotoxicity. Notably, aggregates induced by E46K displayed a distinct morphology compared to other variants. These findings highlight the complexity of α-syn pathology and suggest that different α-syn variants contribute uniquely to PD progression
Beskrivning
Ämne/nyckelord
Parkinson’s disease , α-synuclein , endogenous aggregation , amyloid fibrils , biophysics , in vitro models , primary cell cultures