1. Biochemistry and Chemical Biology
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The C9ORF72 GGGGCC expansion forms RNA G-quadruplex inclusions and sequesters hnRNP H to disrupt splicing in ALS patient brains

  1. Erin G Conlon
  2. Lei Lu
  3. Aarti Sharma
  4. Takashi Yamazaki
  5. Timothy Tang
  6. Neil A Shneider
  7. James L Manley  Is a corresponding author
  1. Columbia University, United States
  2. Columbia University Medical Center, United States
Research Article
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Cite this article as: eLife 2016;5:e17820 doi: 10.7554/eLife.17820

Abstract

An expanded GGGGCC hexanucleotide in C9ORF72 (C9) is the most frequent known cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). It has been proposed that expanded transcripts adopt G-quadruplex (G-Q) structures and associate with proteins, but whether this occurs and contributes to disease is unknown. Here we show first that the protein that predominantly associates with GGGGCC repeat RNA in vitro is the splicing factor hnRNP H, and that this interaction is linked to G-Q formation. We then show that G-Q RNA foci are more abundant in C9 ALS patient fibroblasts and astrocytes compared to those without the expansion, and more frequently colocalize with hnRNP H. Importantly, we demonstrate dysregulated splicing of multiple known hnRNP H-target transcripts in C9 patient brains, which correlates with elevated insoluble hnRNP H/G-Q aggregates. Together, our data implicate C9 expansion-mediated sequestration of hnRNP H as a significant contributor to neurodegeneration in C9 ALS/FTD.

Data availability

The following previously published data sets were used

Article and author information

Author details

  1. Erin G Conlon

    Department of Biological Sciences, Columbia University, New York, United States
    Competing interests
    No competing interests declared.

  2. Lei Lu

    Department of Neurology, Columbia University Medical Center, New York, United States
    Competing interests
    No competing interests declared.

  3. Aarti Sharma

    Department of Neurology, Columbia University Medical Center, New York, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4907-2174

  4. Takashi Yamazaki

    Department of Biological Sciences, Columbia University, New York, United States
    Competing interests
    No competing interests declared.

  5. Timothy Tang

    Department of Biological Sciences, Columbia University, New York, United States
    Competing interests
    No competing interests declared.

  6. Neil A Shneider

    Department of Neurology, Columbia University Medical Center, New York, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3223-7366

  7. James L Manley

    Department of Biological Sciences, Columbia University, New York, United States
    For correspondence
    jlm2@columbia.edu
    Competing interests
    James L Manley, Senior editor, eLife.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-8341-1459

Funding

NIH Office of the Director (Training Grant)

  • Erin G Conlon

NIH Office of the Director (RO1)

  • Neil A Shneider
  • James L Manley

NIH Office of the Director (R35 GM 118136)

  • James L Manley

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

Ethics

Human subjects: Informed consent, including consent to publish, was obtained for human derived fibroblast and astrocyte lines used in this study by the IRB of Columbia University under protocols #AAAB0483 and #AAAC1257. For fibroblasts, written consent was given by the patients, and for astrocytes, written consent was given by the families of the deceased. Human tissue was donated for research purposes by the next of kin.

Reviewing Editor

  1. Douglas L Black, University of California, Los Angeles, United States

Publication history

  1. Received: May 13, 2016
  2. Accepted: September 8, 2016
  3. Accepted Manuscript published: September 13, 2016 (version 1)
  4. Accepted Manuscript updated: September 14, 2016 (version 2)
  5. Accepted Manuscript updated: September 17, 2016 (version 3)
  6. Accepted Manuscript updated: September 21, 2016 (version 4)
  7. Version of Record published: October 4, 2016 (version 5)
  8. Version of Record updated: October 7, 2016 (version 6)
  9. Version of Record updated: October 10, 2016 (version 7)

Copyright

© 2016, Conlon 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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Further reading

    1. Biochemistry and Chemical Biology
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    Unexpected similarities between C9ORF72 and sporadic forms of ALS/FTD suggest a common disease mechanism

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    Research Advance Updated

    Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) represent two ends of a disease spectrum with shared clinical, genetic and pathological features. These include near ubiquitous pathological inclusions of the RNA-binding protein (RBP) TDP-43, and often the presence of a GGGGCC expansion in the C9ORF72 (C9) gene. Previously, we reported that the sequestration of hnRNP H altered the splicing of target transcripts in C9ALS patients (Conlon et al., 2016). Here, we show that this signature also occurs in half of 50 postmortem sporadic, non-C9 ALS/FTD brains. Furthermore, and equally surprisingly, these ‘like-C9’ brains also contained correspondingly high amounts of insoluble TDP-43, as well as several other disease-related RBPs, and this correlates with widespread global splicing defects. Finally, we show that the like-C9 sporadic patients, like actual C9ALS patients, were much more likely to have developed FTD. We propose that these unexpected links between C9 and sporadic ALS/FTD define a common mechanism in this disease spectrum.

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