Label-free characterization of alpha-synuclein spreading in brain using mass-spectrometry imaging

Abstract

This thesis aims to combine immunohistochemistry (IHC) with mass spectrometry imaging (MSI) to investigate the presence of Alzheimer’s disease plaques and the disease-specific pattern in the brains of transgenic mice. This study combines the strength of both techniques to improve understanding of the Alzheimer’s disease-specific proteins and the disease-specific pattern change in mice brains.The desired result is to map the spatial distribution of proteins specific to Alzheimer’s, with a focus on those involved in plaque formation, as well as other changes specific to the disease. This was achieved by applying of the AmberGenT M workflow, which included using highly specific probes to detect specific proteins.The probes selected for this study were GLUT1 (Glucose Transporter 1), GFAP (Glial Fibrillary Acidic Protein), Cathepsin D, NeuN (Neuronal Nuclear Antigen),MBP (Myelin Basic Protein, a membrane protein), and Amyloid β42 (a peptideassociated with Alzheimer’s disease).Mass spectrometry imaging was performed by using Bruker’s Fourier TransformIon Cyclotron Resonance (FTICR) instrument, the scimaX®. This method is known for its high mass resolution and its remarkable mass accuracy. The usage of scimaX® made it possible to detect and analyze proteins, allowing a detailed comparison of their expression level. The aim was to determine which proteins were overexpressed or underexpressed, and to identify those that exhibit similar patterns in brains of healthy and transgenic mice.This study combines the approach of immunohistochemistry with the precision of mass spectrometry imaging for a better understanding of the molecular mechanisms behind Alzheimer’s disease and provides a more detailed view of its pathology.