Rescue of ATXN3 Neuronal Toxicity in Caenorhabditiselegans by Chemical Modification of Endoplasmic Reticulum Stress

Dis Model Mech. 2017 Dec 19;10(12):1465-1480. doi: 10.1242/dmm.029736.

Abstract

Polyglutamine expansion diseases are a group of hereditary neurodegenerative disorders that develop when a CAG repeat in the causative genes is unstably expanded above a certain threshold. The expansion of trinucleotide CAG repeats causes hereditary adult-onset neurodegenerative disorders, such as Huntington's disease, dentatorubral-pallidoluysian atrophy, spinobulbar muscular atrophy and multiple forms of spinocerebellar ataxia (SCA). The most common dominantly inherited SCA is the type 3 (SCA3), also known as Machado-Joseph disease (MJD), which is an autosomal dominant, progressive neurological disorder. The gene causatively associated with MJD is ATXN3 Recent studies have shown that this gene modulates endoplasmic reticulum (ER) stress. We generated transgenic Caenorhabditiselegans strains expressing human ATXN3 genes in motoneurons, and animals expressing mutant ATXN3-CAG89 alleles showed decreased lifespan, impaired movement, and rates of neurodegeneration greater than wild-type ATXN3-CAG10 controls. We tested three neuroprotective compounds (Methylene Blue, guanabenz and salubrinal) believed to modulate ER stress and observed that these molecules rescued ATXN3-CAG89 phenotypes. Furthermore, these compounds required specific branches of the ER unfolded protein response (UPRER), reduced global ER and oxidative stress, and polyglutamine aggregation. We introduce new C. elegans models for MJD based on the expression of full-length ATXN3 in a limited number of neurons. Using these models, we discovered that chemical modulation of the UPRER reduced neurodegeneration and warrants investigation in mammalian models of MJD.

Keywords: Ataxin 3; Caenorhabditis elegans; Endoplasmic reticulum stress; Guanabenz; Polyglutamine.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Ataxin-3 / metabolism*
  • Caenorhabditis elegans / drug effects
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / metabolism*
  • Cinnamates / pharmacology
  • Cinnamates / therapeutic use
  • Endoplasmic Reticulum Stress* / drug effects
  • Guanabenz / pharmacology
  • Guanabenz / therapeutic use
  • Humans
  • Longevity
  • Methylene Blue / pharmacology
  • Methylene Blue / therapeutic use
  • Motor Neurons / pathology*
  • Mutation / genetics
  • Nerve Degeneration / complications
  • Nerve Degeneration / pathology
  • Oxidative Stress / drug effects
  • Paralysis / complications
  • Paralysis / drug therapy
  • Phenotype
  • Protein Aggregates / drug effects
  • Repressor Proteins / metabolism
  • Small Molecule Libraries / pharmacology
  • Small Molecule Libraries / therapeutic use
  • Thiourea / analogs & derivatives
  • Thiourea / pharmacology
  • Thiourea / therapeutic use
  • Transgenes
  • Unfolded Protein Response / drug effects

Substances

  • Caenorhabditis elegans Proteins
  • Cinnamates
  • Protein Aggregates
  • Repressor Proteins
  • Small Molecule Libraries
  • salubrinal
  • ATXN3 protein, human
  • Ataxin-3
  • atx-3 protein, C elegans
  • Guanabenz
  • Thiourea
  • Methylene Blue

Grant support