Network Activity of Antibody Targeted and α/ β -Synuclein Transfected Neurons

by Fabian Hobbie
Doctoral thesis
Date of Examination:2025-06-23
Date of issue:2025-06-16
Advisor:Jan Koch
Referee:Wolfram H. Zimmermann
Referee:Dieter Kube
Persistent Address: http://dx.doi.org/10.53846/goediss-11295

 

 

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Abstract

English

Parkinson’s disease (PD), is characterised pathologically by a loss of dopaminergic neurons in the substantia nigra pars compacta and concomitant aggregation of the pre-synaptic protein α-synuclein (α-syn), mitochondrial dysfunction, glia cell malfunction, and specific morphological features of the neurons such as axonal degeneration. Emerging hypotheses highlight a critical role of a malfunctioning immune system as precipitating event for onset and/or progression of PD as emphasised by high comorbidity rates with various autoimmune disorders, IgG positive Lewy bodies - entailing α-syn - and alterations concerning autoantibodies (AAb) targeted at α-syn. The latter appears potentially intricate as the blood brain barrier (BBB) also seems negatively impacted by the pathology, potentially allowing for AAb extravasation. Therefore, provided α-syn aggregation in PD is linked to neurodegeneration and also reduces rhythmic brain activity, this research sought to determine the effects of α-syn AAbs onto neuronal viability and their functional synchronised network activity. Effects of PD and control sera onto rat cortical neurons’ survival and activity was assessed. AAb levels were quantified by indirect ELISA and Western Blots. We used Adeno-associated viruses (AAV6) to over-express human wild-type synuclein isoforms; Td-Tomato and NLSmCherry, to mark neurons and nuclei; GCamp6, to indirectly assess neuronal activity by Ca 2+ flux analysis using FluoroSNAP; GFAP2.2 EGFP, to detect astrocytes; and BcL-xL to prevent apoptosis. Magnetic bead immunoprecipitation was performed to reduce AAb in sera. Depending on their titre, serum α-syn-AAb substantially reduced viability and network activity in α-syn over-expressing neurons. This effect was neither detectable in control or vehicle control, γ -syn expressing neurons. Importantly, α-syn-AAb depletion of sera rescued their negative impact. Our results imply that α-syn AAbs induce selective and dose-dependent neurodegeneration in an in vitro model of PD. Thus, serum AABs directed against α-syn might be considered therapeutic targets in neurodegenerative diseases with defective blood-brain barriers.
Keywords: Auto-antibodies; Calcium; Network activity; Neurodegeneration; Neurons; Parkinson´s disease; α-synuclein
Schlagwörter: Auto-antibodies; Calcium; Network activity; Neurodegeneration; Neurons; Parkinson´s disease; α-synuclein