Motor neuron disease, TDP-43 pathology, and memory deficits in mice expressing ALS-FTD-linked UBQLN2 mutations

Proc Natl Acad Sci U S A. 2016 Nov 22;113(47):E7580-E7589. doi: 10.1073/pnas.1608432113. Epub 2016 Nov 9.

Abstract

Missense mutations in ubiquilin 2 (UBQLN2) cause ALS with frontotemporal dementia (ALS-FTD). Animal models of ALS are useful for understanding the mechanisms of pathogenesis and for preclinical investigations. However, previous rodent models carrying UBQLN2 mutations failed to manifest any sign of motor neuron disease. Here, we show that lines of mice expressing either the ALS-FTD-linked P497S or P506T UBQLN2 mutations have cognitive deficits, shortened lifespans, and develop motor neuron disease, mimicking the human disease. Neuropathologic analysis of the mice with end-stage disease revealed the accumulation of ubiquitinated inclusions in the brain and spinal cord, astrocytosis, a reduction in the number of hippocampal neurons, and reduced staining of TAR-DNA binding protein 43 in the nucleus, with concomitant formation of ubiquitin+ inclusions in the cytoplasm of spinal motor neurons. Moreover, both lines displayed denervation muscle atrophy and age-dependent loss of motor neurons that correlated with a reduction in the number of large-caliber axons. By contrast, two mouse lines expressing WT UBQLN2 were mostly devoid of clinical and pathological signs of disease. These UBQLN2 mouse models provide valuable tools for identifying the mechanisms underlying ALS-FTD pathogenesis and for investigating therapeutic strategies to halt disease.

Keywords: ALS; TDP-43 pathology; UBQLN2; motor neuron disease.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing
  • Adaptor Proteins, Vesicular Transport / genetics*
  • Adaptor Proteins, Vesicular Transport / metabolism
  • Amyotrophic Lateral Sclerosis / complications
  • Amyotrophic Lateral Sclerosis / genetics*
  • Amyotrophic Lateral Sclerosis / metabolism
  • Animals
  • Autophagy-Related Proteins
  • Cell Nucleus / metabolism
  • Cytoplasm / metabolism
  • DNA-Binding Proteins / metabolism*
  • Disease Models, Animal*
  • Frontotemporal Dementia / etiology
  • Frontotemporal Dementia / genetics*
  • Frontotemporal Dementia / metabolism
  • Humans
  • Inclusion Bodies / metabolism
  • Mice
  • Motor Neurons / metabolism
  • Mutation, Missense*
  • Ubiquitination

Substances

  • Adaptor Proteins, Signal Transducing
  • Adaptor Proteins, Vesicular Transport
  • Autophagy-Related Proteins
  • DNA-Binding Proteins
  • TDP-43 protein, mouse
  • UBQLN2 protein, mouse