Activity-dependent FUS Dysregulation Disrupts Synaptic Homeostasis

Proc Natl Acad Sci U S A. 2014 Nov 4;111(44):E4769-78. doi: 10.1073/pnas.1406162111. Epub 2014 Oct 16.

Abstract

The RNA-binding protein fused-in-sarcoma (FUS) has been associated with amyotrophic lateral sclerosis (ALS) and frontotemporal lobar degeneration (FTLD), two neurodegenerative disorders that share similar clinical and pathological features. Both missense mutations and overexpression of wild-type FUS protein can be pathogenic in human patients. To study the molecular and cellular basis by which FUS mutations and overexpression cause disease, we generated novel transgenic mice globally expressing low levels of human wild-type protein (FUS(WT)) and a pathological mutation (FUS(R521G)). FUS(WT) and FUS(R521G) mice that develop severe motor deficits also show neuroinflammation, denervated neuromuscular junctions, and premature death, phenocopying the human diseases. A portion of FUS(R521G) mice escape early lethality; these escapers have modest motor impairments and altered sociability, which correspond with a reduction of dendritic arbors and mature spines. Remarkably, only FUS(R521G) mice show dendritic defects; FUS(WT) mice do not. Activation of metabotropic glutamate receptors 1/5 in neocortical slices and isolated synaptoneurosomes increases endogenous mouse FUS and FUS(WT) protein levels but decreases the FUS(R521G) protein, providing a potential biochemical basis for the dendritic spine differences between FUS(WT) and FUS(R521G) mice.

Keywords: FUS; amyotrophic lateral sclerosis; frontotemporal lobar degeneration; metabotropic glutamate receptors; synaptic homeostasis.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Substitution*
  • Amyotrophic Lateral Sclerosis* / genetics
  • Amyotrophic Lateral Sclerosis* / metabolism
  • Amyotrophic Lateral Sclerosis* / pathology
  • Animals
  • Dendrites / genetics
  • Dendrites / metabolism
  • Frontotemporal Lobar Degeneration* / genetics
  • Frontotemporal Lobar Degeneration* / metabolism
  • Frontotemporal Lobar Degeneration* / pathology
  • Humans
  • Mice
  • Mice, Transgenic
  • Motor Activity / genetics
  • Mutation, Missense*
  • Neuromuscular Junction* / genetics
  • Neuromuscular Junction* / metabolism
  • Neuromuscular Junction* / pathology
  • RNA-Binding Protein FUS* / genetics
  • RNA-Binding Protein FUS* / metabolism
  • Spine / metabolism
  • Spine / pathology

Substances

  • RNA-Binding Protein FUS