Knocking out C9ORF72 Exacerbates Axonal Trafficking Defects Associated with Hexanucleotide Repeat Expansion and Reduces Levels of Heat Shock Proteins

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Masin Abo-Rady - , Dresden University of Technology (Author)
  • Norman Kalmbach - , Leibniz University Hannover (LUH) (Author)
  • Arun Pal - , Dresden University of Technology (Author)
  • Carina Schludi - , German Center for Neurodegenerative Diseases (DZNE) (Author)
  • Antje Janosch - , Max Planck Institute of Molecular Cell Biology and Genetics (Author)
  • Tanja Richter - , Ulm University (Author)
  • Petra Freitag - , Dresden University of Technology (Author)
  • Marc Bickle - , Max Planck Institute of Molecular Cell Biology and Genetics (Author)
  • Anne Karin Kahlert - , Dresden University of Technology (Author)
  • Susanne Petri - , Leibniz University Hannover (LUH) (Author)
  • Stefan Stefanov - , Dresden University of Technology (Author)
  • Hannes Glass - , Dresden University of Technology, University of Rostock (Author)
  • Selma Staege - , Leibniz University Hannover (LUH) (Author)
  • Walter Just - , Ulm University (Author)
  • Rajat Bhatnagar - , Verge Genomics (Author)
  • Dieter Edbauer - , German Center for Neurodegenerative Diseases (DZNE) (Author)
  • Andreas Hermann - , Dresden University of Technology, University of Rostock, German Center for Neurodegenerative Diseases (DZNE) (Author)
  • Florian Wegner - , Leibniz University Hannover (LUH) (Author)
  • Jared L. Sterneckert - , iPS Cells and Neurodegenerative Disease (Junior Research Group) (Author)

Abstract

In amyotrophic lateral sclerosis (ALS) motor neurons (MNs) undergo dying-back, where the distal axon degenerates before the soma. The hexanucleotide repeat expansion (HRE) in C9ORF72 is the most common genetic cause of ALS, but the mechanism of pathogenesis is largely unknown with both gain- and loss-of-function mechanisms being proposed. To better understand C9ORF72-ALS pathogenesis, we generated isogenic induced pluripotent stem cells. MNs with HRE in C9ORF72 showed decreased axonal trafficking compared with gene corrected MNs. However, knocking out C9ORF72 did not recapitulate these changes in MNs from healthy controls, suggesting a gain-of-function mechanism. In contrast, knocking out C9ORF72 in MNs with HRE exacerbated axonal trafficking defects and increased apoptosis as well as decreased levels of HSP70 and HSP40, and inhibition of HSPs exacerbated ALS phenotypes in MNs with HRE. Therefore, we propose that the HRE in C9ORF72 induces ALS pathogenesis via a combination of gain- and loss-of-function mechanisms. Sterneckert and colleagues generated isogenic induced pluripotent stem cell lines and demonstrated that MNs with hexanucleotide repeat expansion (HRE) in C9ORF72 show reduced axonal trafficking, which is not recapitulated by knocking out C9ORF72 in MNs from healthy individuals. In contrast, knocking out C9ORF72 exacerbated phenotypes in MNs with HRE, suggesting that both gain- and loss-of-function mechanisms contribute to C9ORF72-ALS.

Details

Original languageEnglish
Pages (from-to)390-405
Number of pages16
JournalStem cell reports
Volume14
Issue number3
Publication statusPublished - 10 Mar 2020
Peer-reviewedYes

External IDs

PubMed 32084385
ORCID /0000-0002-7688-3124/work/142250019

Keywords

Keywords

  • amyotrophic lateral sclerosis, axonal trafficking, C9ORF72, disease modeling, gene editing, heat shock proteins, HSP40, HSP70, induced pluripotent stem cells

Library keywords