Prolyl oligopeptidase inhibition attenuates the toxicity of a proteasomal inhibitor, lactacystin, in the alpha-synuclein overexpressing cell culture

Timo T. Myöhänen, Susanna Norrbacka, Mari H. Savolainen

Research output: Contribution to journalArticleScientificpeer-review

16 Citations (Scopus)

Abstract

Lewy bodies, the histopathological hallmarks of Parkinson's disease (PD), contain insoluble and aggregated α-synuclein (aSyn) and many other proteins, proposing a role for failure in protein degradation system in the PD pathogenesis. Proteasomal dysfunction has indeed been linked to PD and aSyn oligomers have been shown to inhibit proteasomes and autophagy. Our recent studies have shown that inhibitors of prolyl oligopeptidase (PREP) can prevent the aggregation and enhance the clearance of accumulated aSyn, and therefore, we wanted to study if PREP inhibition can overcome the aSyn aggregation and toxicity induced by lactacystin, a proteasomal inhibitor. The cells overexpressing human A30P or A53T mutated aSyn were incubated with lactacystin and a PREP inhibitor, KYP-2047, for 48 h. Theafter, the cells were fractioned, and the effects of lactacystin with/without 1 μM KYP-2047 on aSyn aggregation and ubiquitin accumulation, cell viability and on autophagic markers (p62, Beclin1 and LC3BII) were studied. We found that KYP-2047 attenuated lactacystin-induced cell death in mutant aSyn overexpressing cells but not in non-overexpressing control cells. KYP-2047 reduced significantly SDS-insoluble high-molecular-weight aSyn oligomers that were in line with the cell viability results. In addition, significant reduction in protein accumulation marker, p62, was seen in SDS fraction while LC3BII, a marker for autophagosome formation, was increased, indicating to enhanced autophagy. Our results further streghten the possibilities for PREP inhibitors as a potential drug therapy against synucleinopathies and other protein aggregating diseases.

Original languageEnglish
Pages (from-to)83-89
Number of pages7
JournalNeuroscience Letters
Volume636
DOIs
Publication statusPublished - 1 Jan 2017
MoE publication typeA1 Journal article-refereed

Keywords

  • Alpha-synuclein aggregation
  • Enzyme inhibition
  • Parkinson's disease
  • Serine protease
  • Synucleinopathies

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