Inhibition of ER stress improves progressive motor deficits in a REEP1-null mouse model of hereditary spastic paraplegia

Biol Open. 2020 Sep 29;9(9):bio054296. doi: 10.1242/bio.054296.

Abstract

Hereditary spastic paraplegias (HSPs) are genetic neurodegenerative diseases. HSPs are characterized by lower-extremity weakness and spasticity. However, there is no specific clinical treatment strategy to prevent or reverse nerve degeneration in HSPs. Mutations in receptor expression-enhancing protein 1 (REEP1) are well-recognized and relatively common causes of autosomal dominant HSPs. REEP1 modifies the endoplasmic reticulum (ER) shape, and is implicated in the ER stress response. Defects in the ER stress response seem to be crucial mechanisms underlying HSP neurodegeneration. Here, we report that REEP1-/- mice exhibit progressive motor deficits, along with denervation of neuromuscular junctions and increased ER stress. Moreover, marked axonal degeneration and morphological abnormalities are observed. In this study, we treated both REEP1-/- and wild-type (WT) mice with salubrinal, which is a specific inhibitor of ER stress, and we observed increased nerve-muscle connections and enhanced motor functions. Our data highlight the importance of ER homeostasis in HSPs, providing new opportunities for HSP treatment.

Keywords: Endoplasmic reticulum stress; Hereditary spastic paraplegias; Receptor expression-enhancing protein 1; Salubrinal.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Disease Models, Animal
  • Disease Progression
  • Disease Susceptibility*
  • Endoplasmic Reticulum Stress / drug effects*
  • Endoplasmic Reticulum Stress / genetics*
  • Genetic Predisposition to Disease
  • Homozygote
  • Membrane Proteins / deficiency*
  • Mice
  • Motor Activity
  • Motor Neurons / metabolism
  • Motor Neurons / pathology
  • Neuromuscular Junction / genetics
  • Neuromuscular Junction / metabolism
  • Spastic Paraplegia, Hereditary / diagnosis
  • Spastic Paraplegia, Hereditary / etiology*
  • Spastic Paraplegia, Hereditary / metabolism*
  • Spastic Paraplegia, Hereditary / physiopathology

Substances

  • Membrane Proteins
  • REEP2 protein, mouse