Inflammatory osteolysis is regulated by site-specific ISGylation of the scaffold protein NEMO

  1. Naga Suresh Adapala
  2. Gaurav Swarnkar
  3. Manoj Arra
  4. Jie Shen
  5. Gabriel Mbalaviele
  6. Ke Ke
  7. Yousef Abu-Amer  Is a corresponding author
  1. Washington University School of Medicine, United States

Abstract

Inflammatory osteolysis is governed by exacerbated osteoclastogenesis. Ample evidence points to central role of NF-kB in such pathologic responses, yet the precise mechanisms underpinning specificity of these responses remain unclear. We propose that motifs of the scaffold protein IKKg/NEMO partly facilitate such functions. As proof-of-principle, we used site-specific mutagenesis to examine the role of NEMO in mediating RANKL-induced signaling in mouse bone marrow macrophages, known as osteoclast precursors. We identified lysine (K)270 as a target regulating RANKL signaling as K270A substitution results in exuberant osteoclastogenesis in vitro and murine inflammatory osteolysis in vivo. Mechanistically, we discovered that K270A mutation disrupts autophagy, stabilizes NEMO, and elevates inflammatory burden. Specifically, K270A directly or indirectly hinders binding of NEMO to ISG15, a ubiquitin-like protein, which we show targets the modified proteins to autophagy-mediated lysosomal degradation. Taken together, our findings suggest that NEMO serves as a toolkit to fine-tune specific signals in physiologic and pathologic conditions.

Data availability

The following datasets and raw data will be available on Dryad: Proteomics dataset, All Western blot raw data, FACS dataset microCT raw dataset. https://doi.org/10.5061/dryad.tx95x69tn

The following data sets were generated

Article and author information

Author details

  1. Naga Suresh Adapala

    Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Gaurav Swarnkar

    Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  3. Manoj Arra

    Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Jie Shen

    Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  5. Gabriel Mbalaviele

    BMD, Department of Medicine, Washington University School of Medicine, Saint Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Ke Ke

    Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Yousef Abu-Amer

    Orthopaedic Surgery, Washington University School of Medicine, Saint Louis, United States
    For correspondence
    abuamery@wustl.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5890-5086

Funding

National Institutes of Health (AR049192)

  • Yousef Abu-Amer

National Institutes of Health (AR068972)

  • Gabriel Mbalaviele

National Institutes of Health (AR054326)

  • Yousef Abu-Amer

National Institutes of Health (AR072623)

  • Yousef Abu-Amer

National Institutes of Health (AR057235)

  • Yousef Abu-Amer

Shriners Hospital For Children (86200)

  • Yousef Abu-Amer

Shriners Hospital for Children (85160)

  • Yousef Abu-Amer

National Institutes of Health (AR075860)

  • Jie Shen

National Institutes of Health (AR077226)

  • Jie Shen

National Institutes of Health (AR064755)

  • Gabriel Mbalaviele

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

Ethics

Animal experimentation: All the animals were housed at the Washington University School of Medicine barrier facility. All experimental protocols were carried out in accordance with the ethical guidelines approved by the Washington University School of Medicine Institutional Animal Care and Use Committee (approval protocol #20190002).

Copyright

© 2020, Adapala 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. Naga Suresh Adapala
  2. Gaurav Swarnkar
  3. Manoj Arra
  4. Jie Shen
  5. Gabriel Mbalaviele
  6. Ke Ke
  7. Yousef Abu-Amer
(2020)
Inflammatory osteolysis is regulated by site-specific ISGylation of the scaffold protein NEMO
eLife 9:e56095.
https://doi.org/10.7554/eLife.56095

Share this article

https://doi.org/10.7554/eLife.56095

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