Mechanism of impaired microtubule-dependent peroxisome trafficking and oxidative stress in SPAST-mutated cells from patients with Hereditary Spastic Paraplegia

Sci Rep. 2016 May 27:6:27004. doi: 10.1038/srep27004.

Abstract

Hereditary spastic paraplegia (HSP) is an inherited neurological condition that leads to progressive spasticity and gait abnormalities. Adult-onset HSP is most commonly caused by mutations in SPAST, which encodes spastin a microtubule severing protein. In olfactory stem cell lines derived from patients carrying different SPAST mutations, we investigated microtubule-dependent peroxisome movement with time-lapse imaging and automated image analysis. The average speed of peroxisomes in patient-cells was slower, with fewer fast moving peroxisomes than in cells from healthy controls. This was not because of impairment of peroxisome-microtubule interactions because the time-dependent saltatory dynamics of movement of individual peroxisomes was unaffected in patient-cells. Our observations indicate that average peroxisome speeds are less in patient-cells because of the lower probability of individual peroxisome interactions with the reduced numbers of stable microtubules: peroxisome speeds in patient cells are restored by epothilone D, a tubulin-binding drug that increases the number of stable microtubules to control levels. Patient-cells were under increased oxidative stress and were more sensitive than control-cells to hydrogen peroxide, which is primarily metabolised by peroxisomal catalase. Epothilone D also ameliorated patient-cell sensitivity to hydrogen-peroxide. Our findings suggest a mechanism for neurodegeneration whereby SPAST mutations indirectly lead to impaired peroxisome transport and oxidative stress.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Age of Onset
  • Cell Line
  • Epothilones / pharmacology
  • Gene Expression Regulation
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Microtubules / drug effects
  • Microtubules / metabolism*
  • Microtubules / ultrastructure
  • Movement / drug effects
  • Movement / physiology
  • Mutation
  • Neural Stem Cells / drug effects
  • Neural Stem Cells / metabolism*
  • Neural Stem Cells / pathology
  • Olfactory Receptor Neurons / drug effects
  • Olfactory Receptor Neurons / metabolism*
  • Olfactory Receptor Neurons / pathology
  • Oxidative Stress
  • Peroxisomes / drug effects
  • Peroxisomes / metabolism*
  • Peroxisomes / ultrastructure
  • Signal Transduction
  • Spastic Paraplegia, Hereditary / genetics*
  • Spastic Paraplegia, Hereditary / metabolism
  • Spastic Paraplegia, Hereditary / pathology
  • Spastin / genetics*
  • Spastin / metabolism
  • Time-Lapse Imaging
  • Tubulin Modulators / pharmacology

Substances

  • Epothilones
  • Tubulin Modulators
  • Hydrogen Peroxide
  • Spastin
  • SPAST protein, human