Abstract

This study examines how site-specific binding to three identified neurosteroid binding sites in the α1β3 GABAA receptor (GABAAR) contributes to neurosteroid allosteric modulation. We found that the potentiating neurosteroid, allopregnanolone, but not its inhibitory 3β-epimer epi-allopregnanolone, binds to the canonical β3(+)–α1(-) intersubunit site that mediates receptor activation by neurosteroids. In contrast, both allopregnanolone and epi-allopregnanolone bind to intrasubunit sites in the β3 subunit, promoting receptor desensitization and the α1 subunit promoting effects that vary between neurosteroids. Two neurosteroid analogues with diazirine moieties replacing the 3-hydroxyl (KK148 and KK150) bind to all three sites, but do not potentiate GABAAR currents. KK148 is a desensitizing agent, whereas KK150 is devoid of allosteric activity. These compounds provide potential chemical scaffolds for neurosteroid antagonists. Collectively, these data show that differential occupancy and efficacy at three discrete neurosteroid binding sites determine whether a neurosteroid has potentiating, inhibitory, or competitive antagonist activity on GABAARs.

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

Article and author information

Author details

  1. Yusuke Sugasawa

    Department of Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-1607-0460
  2. Wayland WL Cheng

    Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-9529-9820
  3. John R Bracamontes

    Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  4. Zi-Wei Chen

    Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8601-2210
  5. Lei Wang

    Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  6. Allison L Germann

    Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  7. Spencer R Pierce

    Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  8. Thomas C Senneff

    Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  9. Kathiresan Krishnan

    Department of Developmental Biology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  10. David E Reichert

    Radiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  11. Douglas F Covey

    Department of Developmental Biology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  12. Gustav Akk

    Anesthesiology, Washington University in St Louis, St Louis, United States
    Competing interests
    The authors declare that no competing interests exist.
  13. Alex S Evers

    Anesthesiology, Washington University in St Louis, St Louis, United States
    For correspondence
    eversa@wustl.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-0342-0575

Funding

National Institutes of Health (2R01GM108799-05)

  • Alex S Evers

National Institutes of Health (2R01GM108799-05)

  • Douglas F Covey

National Institutes of Health (5K08GM126336-03)

  • Wayland WL Cheng

National Institutes of Health (5R01GM108580-06)

  • Gustav Akk

Taylor Family Institute for Innovative Psychiatric Research

  • Alex S Evers

Taylor Family Institute for Innovative Psychiatric Research

  • Gustav Akk

Taylor Family Institute for Innovative Psychiatric Research

  • Douglas F Covey

Taylor Family Institute for Innovative Psychiatric Research

  • David E Reichert

Taylor Family Institute for Innovative Psychiatric Research

  • Zi-Wei Chen

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

Reviewing Editor

  1. Cynthia M Czajkowski, University of Wisconsin, Madison, United States

Version history

  1. Received: January 20, 2020
  2. Accepted: September 20, 2020
  3. Accepted Manuscript published: September 21, 2020 (version 1)
  4. Version of Record published: October 2, 2020 (version 2)

Copyright

© 2020, Sugasawa 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. Yusuke Sugasawa
  2. Wayland WL Cheng
  3. John R Bracamontes
  4. Zi-Wei Chen
  5. Lei Wang
  6. Allison L Germann
  7. Spencer R Pierce
  8. Thomas C Senneff
  9. Kathiresan Krishnan
  10. David E Reichert
  11. Douglas F Covey
  12. Gustav Akk
  13. Alex S Evers
(2020)
Site-specific effects of neurosteroids on GABAA receptor activation and desensitization
eLife 9:e55331.
https://doi.org/10.7554/eLife.55331

Share this article

https://doi.org/10.7554/eLife.55331

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