Loss of β-glucocerebrosidase activity does not affect alpha-synuclein levels or lysosomal function in neuronal cells

PLoS One. 2013 Apr 8;8(4):e60674. doi: 10.1371/journal.pone.0060674. Print 2013.

Abstract

To date, a plethora of studies have provided evidence favoring an association between Gaucher disease (GD) and Parkinson's disease (PD). GD, the most common lysosomal storage disorder, results from the diminished activity of the lysosomal enzyme β-glucocerebrosidase (GCase), caused by mutations in the β-glucocerebrosidase gene (GBA). Alpha-synuclein (ASYN), a presynaptic protein, has been strongly implicated in PD pathogenesis. ASYN may in part be degraded by the lysosomes and may itself aberrantly impact lysosomal function. Therefore, a putative link between deficient GCase and ASYN, involving lysosomal dysfunction, has been proposed to be responsible for the risk for PD conferred by GBA mutations. In this current work, we aimed to investigate the effects of pharmacological inhibition of GCase on ASYN accumulation/aggregation, as well as on lysosomal function, in differentiated SH-SY5Y cells and in primary neuronal cultures. Following profound inhibition of the enzyme activity, we did not find significant alterations in ASYN levels, or any changes in the clearance or formation of its oligomeric species. We further observed no significant impairment of the lysosomal degradation machinery. These findings suggest that additional interaction pathways together with aberrant GCase and ASYN must govern this complex relation between GD and PD.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Autophagy / drug effects
  • Cell Differentiation / drug effects
  • Cell Line
  • Gaucher Disease / genetics
  • Gaucher Disease / metabolism
  • Glucosylceramidase / antagonists & inhibitors
  • Glucosylceramidase / deficiency*
  • Humans
  • Inositol / analogs & derivatives
  • Inositol / pharmacology
  • Lysosomes / metabolism*
  • Neurons / cytology
  • Neurons / drug effects
  • Neurons / metabolism*
  • Parkinson Disease / genetics
  • Parkinson Disease / metabolism
  • Protein Multimerization
  • Rats
  • alpha-Synuclein / chemistry
  • alpha-Synuclein / genetics
  • alpha-Synuclein / metabolism*

Substances

  • alpha-Synuclein
  • Inositol
  • Glucosylceramidase
  • conduritol epoxide

Grants and funding

This work was supported by a grant from the Hellenic Ministry of Health to LS. Additional funds were provided by grant «Herakleitos» to GD. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.