Two FTD-ALS genes converge on the endosomal pathway to induce TDP-43 pathology and degeneration

Science. 2022 Oct 7;378(6615):94-99. doi: 10.1126/science.abq7860. Epub 2022 Oct 6.

Abstract

Frontotemporal dementia and amyotrophic lateral sclerosis (FTD-ALS) are associated with both a repeat expansion in the C9orf72 gene and mutations in the TANK-binding kinase 1 (TBK1) gene. We found that TBK1 is phosphorylated in response to C9orf72 poly(Gly-Ala) [poly(GA)] aggregation and sequestered into inclusions, which leads to a loss of TBK1 activity and contributes to neurodegeneration. When we reduced TBK1 activity using a TBK1-R228H (Arg228→His) mutation in mice, poly(GA)-induced phenotypes were exacerbated. These phenotypes included an increase in TAR DNA binding protein 43 (TDP-43) pathology and the accumulation of defective endosomes in poly(GA)-positive neurons. Inhibiting the endosomal pathway induced TDP-43 aggregation, which highlights the importance of this pathway and TBK1 activity in pathogenesis. This interplay between C9orf72, TBK1, and TDP-43 connects three different facets of FTD-ALS into one coherent pathway.

MeSH terms

  • Amyotrophic Lateral Sclerosis* / genetics
  • Amyotrophic Lateral Sclerosis* / metabolism
  • Animals
  • C9orf72 Protein* / genetics
  • C9orf72 Protein* / metabolism
  • DNA Repeat Expansion
  • DNA-Binding Proteins* / genetics
  • DNA-Binding Proteins* / metabolism
  • Endosomes / metabolism
  • Frontotemporal Dementia* / genetics
  • Frontotemporal Dementia* / metabolism
  • Mice
  • Mutation
  • Protein Serine-Threonine Kinases* / genetics
  • Protein Serine-Threonine Kinases* / metabolism

Substances

  • C9orf72 Protein
  • DNA-Binding Proteins
  • TDP-43 protein, mouse
  • Protein Serine-Threonine Kinases
  • TBK1 protein, human

Supplementary concepts

  • Frontotemporal Dementia With Motor Neuron Disease