Molecular Mechanisms Mediating the Transfer of Disease-Associated Proteins and Effects on Neuronal Activity

Article type: Research Article

Authors: Brás, Inês C.^a | Khani, Mohammad H.^b | Vasili, Eftychia^a | Möbius, Wiebke^{c; d} | Riedel, Dietmar^e | Parfentev, Iwan^f | Gerhardt, Ellen^a | Fahlbusch, Christiane^a | Urlaub, Henning^{f; g} | Zweckstetter, Markus^{h; i; j} | Gollisch, Tim^b | Outeiro, Tiago F.^{a; k; l; m; *}

Affiliations: [a] Department of Experimental Neurodegeneration, Center for Biostructural Imaging of Neurodegeneration, University Medical Center Göttingen, Göttingen, Germany | [b] Department of Ophthalmology, University Medical Center Göttingen, Göttingen, Germany | [c] Department of Neurogenetics, Max Planck Institute for Experimental Medicine, Göttingen, Germany | [d] Electron Microscopy Core Unit, Max Planck Institute for Experimental Medicine, Göttingen, Germany | [e] Laboratory of Electron Microscopy, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany | [f] Research Group Bioanalytical Mass Spectrometry, Max-Planck-Institute for Biophysical Chemistry, Göttingen, Germany | [g] Bioanalytics, Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany | [h] German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany | [i] Department for NMR-Based Structural Biology, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany | [j] Department of Neurology, University Medical Center Göttingen, Göttingen, Germany | [k] Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany | [l] Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, United Kingdom | [m] Scientific Employee with an Honorary Contract at German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany

Correspondence: [*] Correspondence to: Prof. Dr. Tiago Fleming Outeiro, Department of Experimental Neurodegeneration, University Medical Center Göttingen, Waldweg 33, 37073 Göttingen, Germany. Tel.: +49 (0) 5513913544; Fax: +49 (0) 5513922693; E-mail: touteir@gwdg.de.

Abstract: Background:Various cellular pathways have been implicated in the transfer of disease-related proteins between cells, contributing to disease progression and neurodegeneration. However, the overall effects of protein transfer are still unclear. Objective:Here, we performed a systematic comparison of basic molecular mechanisms involved in the release of alpha-synuclein, Tau, and huntingtin, and evaluated functional effects upon internalization by receiving cells. Methods:Evaluation of protein release to the extracellular space in a free form and in extracellular vesicles using an optimized ultracentrifugation protocol. The extracellular effects of the proteins and extracellular vesicles in primary neuronal cultures were assessed using multi-channel electrophysiological recordings combined with a customized spike sorting framework. Results:We demonstrate cells differentially release free-forms of each protein to the extracellular space. Importantly, neuronal activity is distinctly modulated upon protein internalization in primary cortical cultures. In addition, these disease-related proteins also occur in extracellular vesicles, and are enriched in ectosomes. Internalization of ectosomes and exosomes by primary microglial or astrocytic cells elicits the production of pro-inflammatory cytokines, and modifies spontaneous electrical activity in neurons. Objective:Overall, our study demonstrates that released proteins can have detrimental effects for surrounding cells, and suggests protein release pathways may be exploited as therapeutic targets in different neurodegenerative diseases.

Keywords: Alpha-synuclein, extracellular vesicles, huntingtin, neuronal function, Tau

DOI: 10.3233/JPD-223516

Journal: Journal of Parkinson's Disease, vol. 12, no. 8, pp. 2397-2422, 2022