1. Medicine
Download icon

The role of extracellular matrix phosphorylation on energy dissipation in bone

  1. Stacyann Bailey
  2. Grazyna E Sroga
  3. Betty Hoac
  4. Orestis L Katsamenis
  5. Zehai Wang
  6. Nikolaos Bouropoulos
  7. Marc D McKee
  8. Esben S Sorensen
  9. Philipp J Thurner
  10. Deepak Vashishth  Is a corresponding author
  1. Rensselaer Polytechnic Institute, United States
  2. McGill University, Canada
  3. University of Southampton, United Kingdom
  4. University of Patras, Greece
  5. Aarhus University, Denmark
  6. Vienna University of Technology, Austria
Research Article
  • Cited 0
  • Views 821
  • Annotations
Cite this article as: eLife 2020;9:e58184 doi: 10.7554/eLife.58184

Abstract

Protein phosphorylation, critical for cellular regulatory mechanisms, is implicated in various diseases. However, it remains unknown whether heterogeneity in phosphorylation of key structural proteins alters tissue integrity and organ function. Here, osteopontin phosphorylation level declined in hypo- and hyper- phosphatemia mouse models exhibiting skeletal deformities. Phosphorylation increased cohesion between osteopontin polymers, and adhesion of osteopontin to hydroxyapatite, enhancing energy dissipation. Fracture toughness, a measure of bone's mechanical competence, increased with ex-vivo phosphorylation of wildtype mouse bones and declined with ex-vivo dephosphorylation. In osteopontin deficient mice, global matrix phosphorylation level was not associated with toughness. Our findings suggest that phosphorylated osteopontin promotes fracture toughness in a dose-dependent manner through increased interfacial bond formation. In the absence of osteopontin, phosphorylation increases electrostatic repulsion, protein alignment, and interfilament distance leading to decreased fracture resistance. These mechanisms may be of importance in other connective tissues, and the key to unraveling cell-matrix interactions in diseases.

Data availability

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

Article and author information

Author details

  1. Stacyann Bailey

    Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-9013-2469
  2. Grazyna E Sroga

    Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, United States
    Competing interests
    No competing interests declared.
  3. Betty Hoac

    Faculty of Dentistry, McGill University, Montreal, Canada
    Competing interests
    No competing interests declared.
  4. Orestis L Katsamenis

    Faculty of Engineering and Physical Sciences, University of Southampton, Southampton, United Kingdom
    Competing interests
    No competing interests declared.
  5. Zehai Wang

    Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, United States
    Competing interests
    No competing interests declared.
  6. Nikolaos Bouropoulos

    Department of Material Science, University of Patras, Patras, Greece
    Competing interests
    No competing interests declared.
  7. Marc D McKee

    Faculty of Dentistry, Department of Anatomy and Cell Biology, Faculty of Medicine, McGill University, Montreal, Canada
    Competing interests
    Marc D McKee, MDM is a member of the FRQS Network for Oral and Bone Health Research, and he holds the Canada Research Chair in Biomineralization as part of the Canada Research Chairs program which contributed to the funding of this work..
  8. Esben S Sorensen

    Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-7050-3354
  9. Philipp J Thurner

    Institute of Lightweight Design and Structural Biomechanics, Vienna University of Technology, Vienna, Austria
    Competing interests
    No competing interests declared.
  10. Deepak Vashishth

    Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, United States
    For correspondence
    vashid@rpi.edu
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-5712-0167

Funding

National Institutes of Health (AR 49635)

  • Stacyann Bailey
  • Grazyna E Sroga
  • Zehai Wang
  • Deepak Vashishth

Canadian Institutes of Health Research

  • Betty Hoac
  • Marc D McKee

University of Southampton (Doctoral Prize Fellowship)

  • Orestis L Katsamenis

Canada Research Chairs

  • Marc D McKee

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

Ethics

Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocols (VAS-001-14) of Rensselaer Polytechnic Institute.

Reviewing Editor

  1. Cheryl Ackert-Bicknell, University of Colorado, United States

Publication history

  1. Received: April 23, 2020
  2. Accepted: December 7, 2020
  3. Accepted Manuscript published: December 9, 2020 (version 1)
  4. Accepted Manuscript updated: December 16, 2020 (version 2)
  5. Version of Record published: December 17, 2020 (version 3)

Copyright

© 2020, Bailey 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

  • 821
    Page views
  • 82
    Downloads
  • 0
    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)

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

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

Further reading

    1. Medicine
    2. Neuroscience
    Bilge E Öztürk et al.
    Research Article Updated

    Background:

    Adeno-associated virus (AAV)-mediated gene therapies are rapidly advancing to the clinic, and AAV engineering has resulted in vectors with increased ability to deliver therapeutic genes. Although the choice of vector is critical, quantitative comparison of AAVs, especially in large animals, remains challenging.

    Methods:

    Here, we developed an efficient single-cell AAV engineering pipeline (scAAVengr) to simultaneously quantify and rank efficiency of competing AAV vectors across all cell types in the same animal.

    Results:

    To demonstrate proof-of-concept for the scAAVengr workflow, we quantified – with cell-type resolution – the abilities of naturally occurring and newly engineered AAVs to mediate gene expression in primate retina following intravitreal injection. A top performing variant identified using this pipeline, K912, was used to deliver SaCas9 and edit the rhodopsin gene in macaque retina, resulting in editing efficiency similar to infection rates detected by the scAAVengr workflow. scAAVengr was then used to identify top-performing AAV variants in mouse brain, heart, and liver following systemic injection.

    Conclusions:

    These results validate scAAVengr as a powerful method for development of AAV vectors.

    Funding:

    This work was supported by funding from the Ford Foundation, NEI/NIH, Research to Prevent Blindness, Foundation Fighting Blindness, UPMC Immune Transplant and Therapy Center, and the Van Sloun fund for canine genetic research.

    1. Cell Biology
    2. Medicine
    Kathryn P Trogden et al.
    Research Article Updated

    Heterogeneity of glucose-stimulated insulin secretion (GSIS) in pancreatic islets is physiologically important but poorly understood. Here, we utilize mouse islets to determine how microtubules (MTs) affect secretion toward the vascular extracellular matrix at single cell and subcellular levels. Our data indicate that MT stability in the β-cell population is heterogenous, and that GSIS is suppressed in cells with highly stable MTs. Consistently, MT hyper-stabilization prevents, and MT depolymerization promotes the capacity of single β-cell for GSIS. Analysis of spatiotemporal patterns of secretion events shows that MT depolymerization activates otherwise dormant β-cells via initiation of secretion clusters (hot spots). MT depolymerization also enhances secretion from individual cells, introducing both additional clusters and scattered events. Interestingly, without MTs, the timing of clustered secretion is dysregulated, extending the first phase of GSIS and causing oversecretion. In contrast, glucose-induced Ca2+ influx was not affected by MT depolymerization yet required for secretion under these conditions, indicating that MT-dependent regulation of secretion hot spots acts in parallel with Ca2+ signaling. Our findings uncover a novel MT function in tuning insulin secretion hot spots, which leads to accurately measured and timed response to glucose stimuli and promotes functional β-cell heterogeneity.