Optical pulse labeling studies reveal exogenous seeding slows alpha-synuclein clearance

• Type of Material: Article
• Authors: Cara L Croft, University College London; Giavanna Paterno, University of Florida; Ava R Vause, University of Florida; Lyla A Rowe, University College London; Daniel H Ryu, University of Florida; Marhsall S Goodwin, University of Florida; Corey A Moran, University of Florida; Pedro E Cruz, University of Florida; Benoit I Giasson, University of Florida; Todd Golde, Emory University
• Language: English
• Date: 2022-12-19
• Publisher: NATURE PORTFOLIO
• Publication Version: Final Published Version
• Copyright Statement: © The Author(s) 2022
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/s41531-022-00434-4
• Title of Journal or Parent Work: NPJ PARKINSONS DISEASE
• Volume: 8
• Issue: 1
• Start Page: 173
• End Page: 173
• Grant/Funding Information: C.LC. is supported by a Race Against Dementia Alzheimer’s Research UK fellowship (ARUK-RADF2019A-003) and is based at the UK Dementia Research Institute, which receives its funding from UK DRI Ltd., funded by the UK Medical Research Council, Alzheimer’s Society, and Alzheimer’s Research UK.; This work was also supported by funding from the NIH (U01AG046139 and U01TR003715).
• Keywords: BODY; PATHOLOGY; Neurosciences & Neurology; AGGREGATION; UBIQUITIN; Science & Technology; Life Sciences & Biomedicine; LEWY BODIES; PHOSPHORYLATION; INDUCTION; Neurosciences; DEGRADATION; PROTEIN; PARKINSONS-DISEASE
• Research Categories: Health Sciences, Pharmacology

Abstract

The accumulation of α-synuclein (α-syn) in intracellular formations known as Lewy bodies (LBs) is associated with several neurodegenerative diseases including Parkinson’s disease and Lewy Body Dementia. There is still limited understanding of how α-syn and LB formation is associated with cellular dysfunction and degeneration in these diseases. To examine the clearance and production dynamics of α-syn we transduced organotypic murine brain slice cultures (BSCs) with recombinant adeno-associated viruses (rAAVs) to express Dendra2-tagged human wild-type (WT) and mutant A53T α-syn, with and without the addition of exogenous α-syn fibrillar seeds and tracked them over several weeks in culture using optical pulse labeling. We found that neurons expressing WT or mutant A53T human α-syn show similar rates of α-syn turnover even when insoluble, phosphorylated Ser129 α-syn has accumulated. Taken together, this data reveals α-syn aggregation and overexpression, pSer129 α-syn, nor the A53T mutation affect α-syn dynamics in this system. Prion-type seeding with exogenous α-syn fibrils significantly slows α-syn turnover, in the absence of toxicity but is associated with the accumulation of anti-p62 immunoreactivity and Thiazin Red positivity. Prion-type induction of α-syn aggregation points towards a potential protein clearance deficit in the presence of fibrillar seeds and the ease of this system to explore precise mechanisms underlying these processes. This system facilitates the exploration of α-syn protein dynamics over long-term culture periods. This platform can further be exploited to provide mechanistic insight on what drives this slowing of α-syn turnover and how therapeutics, other genes or different α-syn mutations may affect α-syn protein dynamics.