Varied pathological and therapeutic response effects associated with CHCHD2 mutant and risk variants

Hum Mutat. 2017 Aug;38(8):978-987. doi: 10.1002/humu.23234. Epub 2017 May 22.

Abstract

Mutations and polymorphic risk variant of coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) have been associated with late-onset Parkinson disease. In vivo pathological evidence of CHCHD2 mutations is currently lacking. Utilizing transgenic Drosophila model, we examined the relative pathophysiologic effect of the pathogenic (c.182C>T, p.Thr61Ile and c.434G>A, p.Arg145Gln) and the risk (c.5C>T, p.Pro2Leu) CHCHD2 variants. All the transgenic models exhibited locomotor dysfunction that could be exacerbated by rotenone exposure, dopaminergic neuron degeneration, reduction in lifespan, mitochondrial dysfunction, oxidative stress, and impairment in synaptic transmission. However, both mutants showed more severe early motor dysfunction, dopaminergic neuronal loss, and higher hydrogen peroxide production compared with the risk variant. p.Thr61Ile (co-segregated in three independent PD families) displayed the most severe phenotype followed by p.Arg145Gln (present only in index patient). We treated the transgenic flies with Ebselen, a mitochondrial hydrogen peroxide scavenger compound; Ebselen appears to be more effective in ameliorating motor function in the mutant than the risk variant models. We provide the first in vivo evidence of the pathological effects associated with CHCHD2 mutations. There was a difference in the pathological and drug response effects between the pathogenic and the risk variants. Ebselen may be a useful neuroprotective drug for carriers of CHCHD2 mutations.

Keywords: CHCHD2; Drosophila; Parkinson disease; pathogenic variant; risk variant.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Blotting, Western
  • Dopaminergic Neurons / drug effects
  • Dopaminergic Neurons / metabolism
  • Drosophila
  • Drosophila Proteins / genetics*
  • Female
  • Immunohistochemistry
  • Locomotion / drug effects
  • Male
  • Microscopy, Electron, Transmission
  • Mitochondrial Proteins / genetics*
  • Mutation / genetics
  • Oxidative Stress / drug effects
  • Oxidative Stress / genetics
  • Reverse Transcriptase Polymerase Chain Reaction
  • Rotenone / pharmacology
  • Synaptic Transmission / drug effects
  • Synaptic Transmission / genetics

Substances

  • Drosophila Proteins
  • Mitochondrial Proteins
  • Rotenone