TREM2 regulates purinergic receptor-mediated calcium signaling and motility in human iPSC-derived microglia

  1. Amit Jairaman
  2. Amanda McQuade
  3. Alberto Granzotto
  4. You Jung Kang
  5. Jean Paul Chadarevian
  6. Sunil Gandhi
  7. Ian Parker
  8. Ian Smith
  9. Hansang Cho
  10. Stefano L Sensi
  11. Shivashankar Othy
  12. Mathew Blurton-Jones  Is a corresponding author
  13. Michael D Cahalan  Is a corresponding author
  1. University of California, United States
  2. University of California, Irvine, United States
  3. University of North Carolina, United States
  4. University G d'Annunzio of Chieti-Pescara, Italy

Abstract

The membrane protein TREM2 (Triggering Receptor Expressed on Myeloid cells 2) regulates key microglial functions including phagocytosis and chemotaxis. Loss-of-function variants of TREM2 are associated with increased risk of Alzheimer's disease (AD). Because abnormalities in Ca2+ signaling have been observed in several AD models, we investigated TREM2 regulation of Ca2+ signaling in human induced pluripotent stem cell-derived microglia (iPSC-microglia) with genetic deletion of TREM2. We found that iPSC-microglia lacking TREM2 (TREM2 KO) show exaggerated Ca2+ signals in response to purinergic agonists, such as ADP, that shape microglial injury responses. This ADP hypersensitivity, driven by increased expression of P2Y12 and P2Y13 receptors, results in greater release of Ca2+ from the endoplasmic reticulum (ER) stores, which triggers sustained Ca2+ influx through Orai channels and alters cell motility in TREM2 KO microglia. Using iPSC-microglia expressing the genetically encoded Ca2+ probe, Salsa6f, we found that cytosolic Ca2+ tunes motility to a greater extent in TREM2 KO microglia. Despite showing greater overall displacement, TREM2 KO microglia exhibit reduced directional chemotaxis along ADP gradients. Accordingly, the chemotactic defect in TREM2 KO microglia was rescued by reducing cytosolic Ca2+ using a P2Y12 receptor antagonist. Our results show that loss of TREM2 confers a defect in microglial Ca2+ response to purinergic signals, suggesting a window of Ca2+ signaling for optimal microglial motility.

Data availability

RNA sequencing data referenced in Figure 1- figure supplement 2 is available through Gene Expression Omnibus: GSE157652.

The following data sets were generated

Article and author information

Author details

  1. Amit Jairaman

    Department of Physiology and Biophysics, University of California, Irvine, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-5206-700X
  2. Amanda McQuade

    Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
    Competing interests
    No competing interests declared.
  3. Alberto Granzotto

    Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
    Competing interests
    No competing interests declared.
  4. You Jung Kang

    Department of Mechanical Engineering and Engineering Science, University of North Carolina, Charlotte, United States
    Competing interests
    No competing interests declared.
  5. Jean Paul Chadarevian

    Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
    Competing interests
    No competing interests declared.
  6. Sunil Gandhi

    Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
    Competing interests
    Sunil Gandhi, is a co-founders of NovoGlia Inc..
  7. Ian Parker

    Department of Physiology and Biophysics, University of California, Irvine, Irvine, United States
    Competing interests
    No competing interests declared.
  8. Ian Smith

    Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-9910-195X
  9. Hansang Cho

    Department of Mechanical Engineering and Engineering Science, University of North Carolina, Charlotte, United States
    Competing interests
    No competing interests declared.
  10. Stefano L Sensi

    Department of Neuroscience, Imaging and Clinical Sciences, University G d'Annunzio of Chieti-Pescara, Chieti, Italy
    Competing interests
    No competing interests declared.
  11. Shivashankar Othy

    Department of Physiology and Biophysics, University of California, Irvine, Irvine, United States
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-6832-5547
  12. Mathew Blurton-Jones

    Department of Neurobiology and Behavior, University of California, Irvine, Irvine, United States
    For correspondence
    mblurton@uci.edu
    Competing interests
    Mathew Blurton-Jones, is a co-inventor of patent application WO/2018/160496, related to the differentiation of pluripotent stem cells into microglia. Is a co-founders of NovoGlia Inc..
  13. Michael D Cahalan

    Department of Physiology and Biophysics, University of California, Irvine, Irvine, United States
    For correspondence
    mcahalan@uci.edu
    Competing interests
    No competing interests declared.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-4987-2526

Funding

National Institutes of Health (R01 NS14609)

  • Michael D Cahalan

National Institutes of Health (R01 AI121945)

  • Michael D Cahalan

National Institutes of Health (R01 AG048099)

  • Mathew Blurton-Jones

National Institutes of Health (R01 AG056303)

  • Mathew Blurton-Jones

National Institutes of Health (R01 AG055524)

  • Mathew Blurton-Jones

National Institutes of Health (core AG066519)

  • Mathew Blurton-Jones

National Institutes of Health (U01 AI160397)

  • Shivashankar Othy

National Institutes of Health (T32 NS082174)

  • Amanda McQuade

National Institutes of Health (RF1DA048813)

  • Sunil Gandhi

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

Ethics

Human subjects: Human iPSC lines were generated by the University of California Alzheimer's Disease Research Center (UCI ADRC) stem cell core. Subject fibroblasts were collected under approved Institutional Review Boards (IRB) and human Stem Cell Research Oversight (hSCRO) committee protocols. Informed consent was received for all participants.

Reviewing Editor

  1. Murali Prakriya, Northwestern University, United States

Publication history

  1. Received: August 13, 2021
  2. Preprint posted: August 24, 2021 (view preprint)
  3. Accepted: February 18, 2022
  4. Accepted Manuscript published: February 22, 2022 (version 1)
  5. Version of Record published: March 9, 2022 (version 2)
  6. Version of Record updated: March 22, 2022 (version 3)

Copyright

© 2022, Jairaman 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. Amit Jairaman
  2. Amanda McQuade
  3. Alberto Granzotto
  4. You Jung Kang
  5. Jean Paul Chadarevian
  6. Sunil Gandhi
  7. Ian Parker
  8. Ian Smith
  9. Hansang Cho
  10. Stefano L Sensi
  11. Shivashankar Othy
  12. Mathew Blurton-Jones
  13. Michael D Cahalan
(2022)
TREM2 regulates purinergic receptor-mediated calcium signaling and motility in human iPSC-derived microglia
eLife 11:e73021.
https://doi.org/10.7554/eLife.73021

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