Aggregated Alpha-Synuclein Transfer Efficiently between Cultured Human Neuron-Like Cells and Localize to Lysosomes

PLoS One. 2016 Dec 28;11(12):e0168700. doi: 10.1371/journal.pone.0168700. eCollection 2016.

Abstract

Parkinson's disease and other alpha-synucleinopathies are progressive neurodegenerative diseases characterized by aggregates of misfolded alpha-synuclein spreading throughout the brain. Recent evidence suggests that the pathological progression is likely due to neuron-to-neuron transfer of these aggregates between neuroanatomically connected areas of the brain. As the impact of this pathological spreading mechanism is currently debated, we aimed to investigate the transfer and subcellular location of alpha-synuclein species in a novel 3D co-culture human cell model based on highly differentiated SH-SY5Y cells. Fluorescently-labeled monomeric, oligomeric and fibrillar species of alpha-synuclein were introduced into a donor cell population and co-cultured with an EGFP-expressing acceptor-cell population of differentiated neuron-like cells. Subsequent transfer and colocalization of the different species were determined with confocal microscopy. We could confirm cell-to-cell transfer of all three alpha-synuclein species investigated. Interestingly the level of transferred oligomers and fibrils and oligomers were significantly higher than monomers, which could affect the probability of seeding and pathology in the recipient cells. Most alpha-synuclein colocalized with the lysosomal/endosomal system, both pre- and postsynaptically, suggesting its importance in the processing and spreading of alpha-synuclein.

MeSH terms

  • Cell Differentiation / drug effects
  • Cell Line, Tumor
  • Coculture Techniques
  • Endosomes / drug effects
  • Endosomes / metabolism
  • Humans
  • Lysosomes / drug effects
  • Lysosomes / metabolism*
  • Neurons / cytology*
  • Protein Aggregates*
  • Protein Multimerization
  • Protein Structure, Quaternary
  • Protein Transport
  • Synapses / drug effects
  • Synapses / metabolism
  • alpha-Synuclein / chemistry*
  • alpha-Synuclein / metabolism*
  • alpha-Synuclein / toxicity

Substances

  • Protein Aggregates
  • alpha-Synuclein

Grant support

This research was made possible by funding from the Swedish Research Council (MH: 523-2013-2735), The Swedish Brain Power Program, The Research Foundation of the Swedish Parkinson’s Disease Association, Östergötland Research Foundation for Parkinson’s Disease, Parkinson Research Foundation, the Hans-Gabriel and Alice Trolle-Wachtmeister Foundation for Medical Research, Gustav V and Queen Victoria’s Foundation, Swedish Dementia Foundation, the Linköping University Neurobiology Centre and the County Council of Östergötland, Marianne and Marcus Wallenberg Foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.