Synapsin III deficiency hampers α-synuclein aggregation, striatal synaptic damage and nigral cell loss in an AAV-based mouse model of Parkinson’s disease

Research output: Contribution to journalArticle

Abstract

Parkinson’s disease (PD), the most common neurodegenerative movement disorder, is characterized by the progressive loss of nigral dopamine neurons. The deposition of fibrillary aggregated α-synuclein in Lewy bodies (LB), that is considered to play a causative role in the disease, constitutes another key neuropathological hallmark of PD. We have recently described that synapsin III (Syn III), a synaptic phosphoprotein that regulates dopamine release in cooperation with α-synuclein, is present in the α-synuclein insoluble fibrils composing the LB of patients affected by PD. Moreover, we observed that silencing of Syn III gene could prevent α-synuclein fibrillary aggregation in vitro. This evidence suggests that Syn III might be crucially involved in α-synuclein pathological deposition. To test this hypothesis, we studied whether mice knock-out (ko) for Syn III might be protected from α-synuclein aggregation and nigrostriatal neuron degeneration resulting from the unilateral injection of adeno-associated viral vectors (AAV)-mediating human wild-type (wt) α-synuclein overexpression (AAV-hαsyn). We found that Syn III ko mice injected with AAV-hαsyn did not develop fibrillary insoluble α-synuclein aggregates, showed reduced amount of α-synuclein oligomers detected by in situ proximity ligation assay (PLA) and lower levels of Ser129-phosphorylated α-synuclein. Moreover, the nigrostriatal neurons of Syn III ko mice were protected from both synaptic damage and degeneration triggered by the AAV-hαsyn injection. Our observations indicate that Syn III constitutes a crucial mediator of α-synuclein aggregation and toxicity and identify Syn III as a novel therapeutic target for PD.

Details

Authors
  • Gaia Faustini
  • Francesca Longhena
  • Tatiana Varanita
  • Luigi Bubacco
  • Marina Pizzi
  • Cristina Missale
  • Fabio Benfenati
  • Anders Björklund
  • Pier Franco Spano
  • Arianna Bellucci
Organisations
External organisations
  • University of Brescia
  • University of Padova
  • Italian Institute of Technology
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Neurosciences

Keywords

  • AAV, Nigrostriatal degeneration, Syn III, Synaptic proteins alterations, α-Synuclein aggregation
Original languageEnglish
Pages (from-to)621-639
Number of pages19
JournalActa Neuropathologica
Volume136
Issue number4
Publication statusPublished - 2018 Oct 1
Publication categoryResearch
Peer-reviewedYes