Abstract

Insulin gene mutations are a leading cause of neonatal diabetes. They can lead to proinsulin misfolding and its retention in endoplasmic reticulum (ER). This results in increased ER-stress suggested to trigger beta-cell apoptosis. In humans, the mechanisms underlying beta-cell failure remain unclear. Here we show that misfolded proinsulin impairs developing beta-cell proliferation without increasing apoptosis. We generated induced pluripotent stem cells (iPSCs) from people carrying insulin (INS) mutations, engineered isogenic CRISPR-Cas9 mutation-corrected lines and differentiated them to beta-like cells. Single-cell RNA-sequencing analysis showed increased ER-stress and reduced proliferation in INS-mutant beta-like cells compared with corrected controls. Upon transplantation into mice, INS-mutant grafts presented reduced insulin secretion and aggravated ER-stress. Cell size, mTORC1 signaling, and respiratory chain subunits expression were all reduced in INS-mutant beta-like cells, yet apoptosis was not increased at any stage. Our results demonstrate that neonatal diabetes-associated INS-mutations lead to defective beta-cell mass expansion, contributing to diabetes development.

Data availability

Single cell RNA sequencing raw data was deposited in GEO under GSE115257Source data for single cell RNA sequencing as well as code scripts for analysis have been provided.

The following data sets were generated
The following previously published data sets were used

Article and author information

Author details

  1. Diego Balboa

    Molecular Neurology Research Program Unit, University of Helsinki, Helsinki, Finland
    For correspondence
    diego.balboa@helsinki.fi
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4784-5452
  2. Jonna Saarimäki-Vire

    Molecular Neurology Research Program Unit, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
  3. Daniel Borshagovski

    Department of Biosciences, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
  4. Mantas Survila

    Department of Biosciences, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
  5. Päivi Lindholm

    Institute of Biotechnology, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3022-5035
  6. Emilia Galli

    Institute of Biotechnology, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7419-611X
  7. Solja Eurola

    Molecular Neurology Research Program Unit, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
  8. Jarkko Ustinov

    Molecular Neurology Research Program Unit, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
  9. Heli Grym

    Molecular Neurology Research Program Unit, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
  10. Hanna Huopio

    University of Eastern Finland, Kuopio, Finland
    Competing interests
    The authors declare that no competing interests exist.
  11. Juha Partanen

    Department of Biosciences, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
  12. Kirmo Wartiovaara

    Molecular Neurology Research Program Unit, University of Helsinki, Helsinki, Finland
    Competing interests
    The authors declare that no competing interests exist.
  13. Timo Otonkoski

    Molecular Neurology Research Program, University of Helsinki, Helsinki, Finland
    For correspondence
    timo.otonkoski@helsinki.fi
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-9190-2496

Funding

Suomen Akatemia

  • Timo Otonkoski

Sigrid Juselius Foundation

  • Timo Otonkoski

Novo Nordisk Foundation

  • Timo Otonkoski

EU 7FP Integrated project BETACURE

  • Timo Otonkoski

Diabetes Research Foundation

  • Timo Otonkoski

Diabetes Wellness Foundation

  • Diego Balboa
  • Jonna Saarimäki-Vire

Biomedicum Helsinki Foundation

  • Diego Balboa

INNODIA

  • Timo Otonkoski

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

Ethics

Animal experimentation: Animal care and experiments were conducted as approved by the National Animal Experiment Board in Finland (ESAVI/9978/04.10.07/2014).

Human subjects: The Coordinating Ethics Committee of the Helsinki and Uusimaa Hospital District (no. 423/13/03/00/08) approved the patient informed consent for the derivation of the hiPSC lines used in this study: HEL71.4 and HEL107.2.

Copyright

© 2018, Balboa 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. Diego Balboa
  2. Jonna Saarimäki-Vire
  3. Daniel Borshagovski
  4. Mantas Survila
  5. Päivi Lindholm
  6. Emilia Galli
  7. Solja Eurola
  8. Jarkko Ustinov
  9. Heli Grym
  10. Hanna Huopio
  11. Juha Partanen
  12. Kirmo Wartiovaara
  13. Timo Otonkoski
(2018)
Insulin mutations impair beta-cell development in a patient-derived iPSC model of neonatal diabetes
eLife 7:e38519.
https://doi.org/10.7554/eLife.38519

Share this article

https://doi.org/10.7554/eLife.38519

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