Distinct insulin granule subpopulations implicated in the secretory pathology of diabetes types 1 and 2

Abstract

Insulin secretion from β-cells is reduced at the onset of type-1 and during type-2 diabetes. Although inflammation and metabolic dysfunction of β-cells elicit secretory defects associated with type-1 or type-2 diabetes, accompanying changes to insulin granules have not been established. To address this, we performed detailed functional analyses of insulin granules purified from cells subjected to model treatments that mimic type-1 and type-2 diabetic conditions and discovered striking shifts in calcium affinities and fusion characteristics. We show that this behavior is correlated with two subpopulations of insulin granules whose relative abundance is differentially shifted depending on diabetic model condition. The two types of granules have different release characteristics, distinct lipid and protein compositions, and package different secretory contents alongside insulin. This complexity of β-cell secretory physiology establishes a direct link between granule subpopulation and type of diabetes and leads to a revised model of secretory changes in the diabetogenic process.

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. Alex JB Kreutzberger

    Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9774-115X
  2. Volker Kiessling

    Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9388-5703
  3. Catherine A Doyle

    Pharmacology, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Noah Schenk

    Pharmacology, University of Michigan, Ann Arbor, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Clint M Upchurch

    Pharmacology, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Margaret Elmer-Dixon

    Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Amanda E Ward

    Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Julia Preobraschenski

    Neurobiology, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany
    Competing interests
    The authors declare that no competing interests exist.
  9. Syed S Hussein

    Microbiology, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  10. Weronika Tomaka

    Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  11. Patrick Seelheim

    Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  12. Iman Kattan

    Neurobiology, Max Planck Institute of Biophysical Chemistry, Göttingen, Germany
    Competing interests
    The authors declare that no competing interests exist.
  13. Megan Harris

    Cell Biology, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  14. Binyong Liang

    Cell Biology, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  15. Anne K Kenworthy

    Cell Biology, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  16. Bimal N Desai

    Pharmacology, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-3928-5854
  17. Norbert Leitinger

    Pharmacology, University of Virginia, Charlottesville, United States
    Competing interests
    The authors declare that no competing interests exist.
  18. Arun Anatharam

    Pharmacology, University of Michigan, Ann Arbor, United States
    Competing interests
    The authors declare that no competing interests exist.
  19. J David Castle

    Cell Biology, University of Virginia, Charlottesville, United States
    For correspondence
    jdc4r@virginia.edu
    Competing interests
    The authors declare that no competing interests exist.
  20. Lukas K Tamm

    Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, United States
    For correspondence
    lkt2e@virginia.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-1674-4464

Funding

National Institutes of Health (P01 GM072694)

  • Lukas K Tamm

National Institutes of Health (R01 DK091296)

  • J David Castle

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

Reviewing Editor

  1. Suzanne R Pfeffer, Stanford University School of Medicine, United States

Publication history

  1. Received: August 26, 2020
  2. Accepted: November 6, 2020
  3. Accepted Manuscript published: November 9, 2020 (version 1)
  4. Version of Record published: December 15, 2020 (version 2)

Copyright

© 2020, Kreutzberger 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.

Metrics

  • 1,920
    Page views
  • 330
    Downloads
  • 9
    Citations

Article citation count generated by polling the highest count across the following sources: Crossref, PubMed Central, Scopus.

Download links

A two-part list of links to download the article, or parts of the article, in various formats.

Downloads (link to download the article as PDF)

Open citations (links to open the citations from this article in various online reference manager services)

Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)

  1. Alex JB Kreutzberger
  2. Volker Kiessling
  3. Catherine A Doyle
  4. Noah Schenk
  5. Clint M Upchurch
  6. Margaret Elmer-Dixon
  7. Amanda E Ward
  8. Julia Preobraschenski
  9. Syed S Hussein
  10. Weronika Tomaka
  11. Patrick Seelheim
  12. Iman Kattan
  13. Megan Harris
  14. Binyong Liang
  15. Anne K Kenworthy
  16. Bimal N Desai
  17. Norbert Leitinger
  18. Arun Anatharam
  19. J David Castle
  20. Lukas K Tamm
(2020)
Distinct insulin granule subpopulations implicated in the secretory pathology of diabetes types 1 and 2
eLife 9:e62506.
https://doi.org/10.7554/eLife.62506

Further reading

    1. Cell Biology
    2. Developmental Biology
    Anna Keppner et al.
    Research Article Updated

    Spermatogenesis is a highly specialized differentiation process driven by a dynamic gene expression program and ending with the production of mature spermatozoa. Whereas hundreds of genes are known to be essential for male germline proliferation and differentiation, the contribution of several genes remains uncharacterized. The predominant expression of the latest globin family member, androglobin (Adgb), in mammalian testis tissue prompted us to assess its physiological function in spermatogenesis. Adgb knockout mice display male infertility, reduced testis weight, impaired maturation of elongating spermatids, abnormal sperm shape, and ultrastructural defects in microtubule and mitochondrial organization. Epididymal sperm from Adgb knockout animals display multiple flagellar malformations including coiled, bifid or shortened flagella, and erratic acrosomal development. Following immunoprecipitation and mass spectrometry, we could identify septin 10 (Sept10) as interactor of Adgb. The Sept10-Adgb interaction was confirmed both in vivo using testis lysates and in vitro by reciprocal co-immunoprecipitation experiments. Furthermore, the absence of Adgb leads to mislocalization of Sept10 in sperm, indicating defective manchette and sperm annulus formation. Finally, in vitro data suggest that Adgb contributes to Sept10 proteolysis in a calmodulin-dependent manner. Collectively, our results provide evidence that Adgb is essential for murine spermatogenesis and further suggest that Adgb is required for sperm head shaping via the manchette and proper flagellum formation.

    1. Biochemistry and Chemical Biology
    2. Cell Biology
    Morgan L Pimm et al.
    Research Article Updated

    Profilin-1 (PFN1) is a cytoskeletal protein that regulates the dynamics of actin and microtubule assembly. Thus, PFN1 is essential for the normal division, motility, and morphology of cells. Unfortunately, conventional fusion and direct labeling strategies compromise different facets of PFN1 function. As a consequence, the only methods used to determine known PFN1 functions have been indirect and often deduced in cell-free biochemical assays. We engineered and characterized two genetically encoded versions of tagged PFN1 that behave identical to each other and the tag-free protein. In biochemical assays purified proteins bind to phosphoinositide lipids, catalyze nucleotide exchange on actin monomers, stimulate formin-mediated actin filament assembly, and bound tubulin dimers (kD = 1.89 µM) to impact microtubule dynamics. In PFN1-deficient mammalian cells, Halo-PFN1 or mApple-PFN1 (mAp-PEN1) restored morphological and cytoskeletal functions. Titrations of self-labeling Halo-ligands were used to visualize molecules of PFN1. This approach combined with specific function-disrupting point-mutants (Y6D and R88E) revealed PFN1 bound to microtubules in live cells. Cells expressing the ALS-associated G118V disease variant did not associate with actin filaments or microtubules. Thus, these tagged PFN1s are reliable tools for studying the dynamic interactions of PFN1 with actin or microtubules in vitro as well as in important cell processes or disease-states.