TFEB/Mitf links impaired nuclear import to autophagolysosomal dysfunction in C9-ALS

Abstract

Disrupted nucleocytoplasmic transport (NCT) has been implicated in neurodegenerative disease pathogenesis; however, the mechanisms by which disrupted NCT causes neurodegeneration remain unclear. In a Drosophila screen, we identified ref(2)P/p62, a key regulator of autophagy, as a potent suppressor of neurodegeneration caused by the GGGGCC hexanucleotide repeat expansion (G4C2 HRE) in C9orf72 that causes amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). We found that p62 is increased and forms ubiquitinated aggregates due to decreased autophagic cargo degradation. Immunofluorescence and electron microscopy of Drosophila tissues demonstrate an accumulation of lysosome-like organelles that precedes neurodegeneration. These phenotypes are partially caused by cytoplasmic mislocalization of Mitf/TFEB, a key transcriptional regulator of autophagolysosomal function. Additionally, TFEB is mislocalized and downregulated in human cells expressing GGGGCC repeats and in C9-ALS patient motor cortex. Our data suggest that the C9orf72-HRE impairs Mitf/TFEB nuclear import, thereby disrupting autophagy and exacerbating proteostasis defects in C9-ALS/FTD.

Data availability

All data generated or analysed during this study are included in the manuscript and supporting files.

Article and author information

Author details

  1. Kathleen M Cunningham

    Neurology, Johns Hopkins University, Baltimore, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1347-9087
  2. Kirstin Maulding

    Neurology, Johns Hopkins University, Baltimore, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-2012-9747
  3. Kai Ruan

    Neurology, Johns Hopkins University, Baltimore, United States
    Competing interests
    No competing interests declared.
  4. Mumine Senturk

    Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
    Competing interests
    No competing interests declared.
  5. Jonathan C Grima

    Brain Science Institute, Johns Hopkins University, Baltimore, United States
    Competing interests
    No competing interests declared.
  6. Hyun Sung

    Neurology, Johns Hopkins University, Baltimore, United States
    Competing interests
    No competing interests declared.
  7. Zhongyuan Zuo

    Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
    Competing interests
    No competing interests declared.
  8. Helen Song

    Neurology, Johns Hopkins University, Baltimore, United States
    Competing interests
    No competing interests declared.
  9. Junli Gao

    Neuroscience, Mayo Clinic, Jacksonville, United States
    Competing interests
    No competing interests declared.
  10. Sandeep Dubey

    Neurology, Johns Hopkins University, Baltimore, United States
    Competing interests
    No competing interests declared.
  11. Jeffrey D Rothstein

    Brain Science Institute, Johns Hopkins University, Baltimore, United States
    Competing interests
    No competing interests declared.
  12. Ke Zhang

    Neuroscience, Mayo Clinic, Jacksonville, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4794-8355
  13. Hugo J Bellen

    Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, United States
    Competing interests
    Hugo J Bellen, Reviewing editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5992-5989
  14. Thomas E Lloyd

    Neurology, Johns Hopkins University, Baltimore, United States
    For correspondence
    tlloyd4@jhmi.edu
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-4756-3700

Funding

National Institute of Neurological Disorders and Stroke (R01NS082563,R01NS094239,P30NS050274,F31NS100401)

  • Thomas E Lloyd

Amyotrophic Lateral Sclerosis Association (17-IIP-370)

  • Thomas E Lloyd

National Institute of General Medical Sciences (P40OD018537)

  • Hugo J Bellen

Howard Hughes Medical Institute

  • Hugo J Bellen

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Reviewing Editor

  1. Harry T Orr, University of Minnesota, United States

Ethics

Human subjects: The use of human tissue and associated decedents' demographic information was approved by the Johns Hopkins University Institutional Review Board and ethics committee (HIPAA Form 5 exemption, Application 11-02-10-01RD) and from the Ravitz Laboratory (UCSD) through the Target ALS Consortium.

Version history

  1. Received: May 28, 2020
  2. Accepted: December 9, 2020
  3. Accepted Manuscript published: December 10, 2020 (version 1)
  4. Version of Record published: December 23, 2020 (version 2)
  5. Version of Record updated: December 31, 2020 (version 3)

Copyright

© 2020, Cunningham et al.

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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  1. Kathleen M Cunningham
  2. Kirstin Maulding
  3. Kai Ruan
  4. Mumine Senturk
  5. Jonathan C Grima
  6. Hyun Sung
  7. Zhongyuan Zuo
  8. Helen Song
  9. Junli Gao
  10. Sandeep Dubey
  11. Jeffrey D Rothstein
  12. Ke Zhang
  13. Hugo J Bellen
  14. Thomas E Lloyd
(2020)
TFEB/Mitf links impaired nuclear import to autophagolysosomal dysfunction in C9-ALS
eLife 9:e59419.
https://doi.org/10.7554/eLife.59419

Share this article

https://doi.org/10.7554/eLife.59419

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