1. Immunology and Inflammation

A genetic screen in macrophages identifies new regulators of IFNγ-inducible MHCII that contribute to T cell activation

  1. Michael C Kiritsy
  2. Laurisa M Ankley
  3. Justin Trombley
  4. Gabrielle P Huizinga
  5. Audrey E Lord
  6. Pontus Orning
  7. Roland Elling
  8. Katherine A Fitzgerald
  9. Andrew J Olive  Is a corresponding author
  1. University of Massachusetts Medical School, United States
  2. Michigan State University, United States
https://doi.org/10.7554/eLife.65110
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Cite this article
  1. Michael C Kiritsy
  2. Laurisa M Ankley
  3. Justin Trombley
  4. Gabrielle P Huizinga
  5. Audrey E Lord
  6. Pontus Orning
  7. Roland Elling
  8. Katherine A Fitzgerald
  9. Andrew J Olive
(2021)
A genetic screen in macrophages identifies new regulators of IFNγ-inducible MHCII that contribute to T cell activation
eLife 10:e65110.
https://doi.org/10.7554/eLife.65110
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  3. Download .RIS

Abstract

Cytokine-mediated activation of host immunity is central to the control of pathogens. Interferon-gamma (IFNγ) is a key cytokine in protective immunity that induces major histocompatibility complex class II molecules (MHCII) to amplify CD4+ T cell activation and effector function. Despite its central role, the dynamic regulation of IFNg-induced MHCII is not well understood. Using a genome-wide CRISPR-Cas9 screen in murine macrophages we identified genes that control MHCII surface expression. Mechanistic studies uncovered two parallel pathways of IFNg-mediated MHCII control that require the multifunctional glycogen synthase kinase 3 beta (GSK3β) or the mediator complex subunit MED16. Both pathways control distinct aspects of the IFNg response and are necessary for IFNg-mediated induction of the MHCII transactivator Ciita, MHCII expression, and CD4+ T cell activation. Our results define previously unappreciated regulation of MHCII expression that is required to control CD4+ T cell responses.

Data availability

Raw sequencing data in FASTQ and processed formats is available for download from NCBI Gene Expression Omnibus (GEO) under accession number GSE162463 (CRISPR Screen) and GSE162464 (RNA sequencing).

The following data sets were generated

Article and author information

Author details

  1. Michael C Kiritsy

    Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0001-8364-8088

  2. Laurisa M Ankley

    Microbiology and Molecular Genetics, Michigan State University, East Lansing, United States
    Competing interests
    The authors declare that no competing interests exist.

  3. Justin Trombley

    Microbiology and Molecular Genetics, Michigan State University, East Lansing, United States
    Competing interests
    The authors declare that no competing interests exist.

  4. Gabrielle P Huizinga

    Microbiology and Molecular Genetics, Michigan State University, East Lansing, United States
    Competing interests
    The authors declare that no competing interests exist.

  5. Audrey E Lord

    Microbiology and Physiological Systems, University of Massachusetts Medical School, Worcester, United States
    Competing interests
    The authors declare that no competing interests exist.

  6. Pontus Orning

    Medicine: Infectious Disease and Immunology, University of Massachusetts Medical School, Worcester, United States
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0002-6177-6916

  7. Roland Elling

    Medicine: Infectious Disease and Immunology, University of Massachusetts Medical School, Worcester, United States
    Competing interests
    The authors declare that no competing interests exist.

  8. Katherine A Fitzgerald

    Medicine: Infectious Disease and Immunology, University of Massachusetts Medical School, Worcester, United States
    Competing interests
    The authors declare that no competing interests exist.

  9. Andrew J Olive

    Microbiology and Molecular Genetics, Michigan State University, East Lansing, United States
    For correspondence
    oliveand@msu.edu
    Competing interests
    The authors declare that no competing interests exist.
    ORCID icon "This ORCID iD identifies the author of this article:" 0000-0003-3441-3113

Funding

National Institutes of Health (AI146504)

  • Andrew J Olive

U.S. Department of Agriculture (NIFA HATCH 1019371)

  • Andrew J Olive

National Institutes of Health (AI132130)

  • Michael C Kiritsy

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 (PROTO201800057) of Michigan State University.

Copyright

© 2021, Kiritsy 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. Michael C Kiritsy
  2. Laurisa M Ankley
  3. Justin Trombley
  4. Gabrielle P Huizinga
  5. Audrey E Lord
  6. Pontus Orning
  7. Roland Elling
  8. Katherine A Fitzgerald
  9. Andrew J Olive
(2021)
A genetic screen in macrophages identifies new regulators of IFNγ-inducible MHCII that contribute to T cell activation
eLife 10:e65110.
https://doi.org/10.7554/eLife.65110

Share this article

https://doi.org/10.7554/eLife.65110

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Further reading

    1. Immunology and Inflammation

    Mitochondrial respiration contributes to the interferon gamma response in antigen-presenting cells

    Michael C Kiritsy, Katelyn McCann ... Andrew J Olive
    Research Article Updated

    The immunological synapse allows antigen-presenting cells (APCs) to convey a wide array of functionally distinct signals to T cells, which ultimately shape the immune response. The relative effect of stimulatory and inhibitory signals is influenced by the activation state of the APC, which is determined by an interplay between signal transduction and metabolic pathways. While pathways downstream of toll-like receptors rely on glycolytic metabolism for the proper expression of inflammatory mediators, little is known about the metabolic dependencies of other critical signals such as interferon gamma (IFNγ). Using CRISPR-Cas9, we performed a series of genome-wide knockout screens in murine macrophages to identify the regulators of IFNγ-inducible T cell stimulatory or inhibitory proteins MHCII, CD40, and PD-L1. Our multiscreen approach enabled us to identify novel pathways that preferentially control functionally distinct proteins. Further integration of these screening data implicated complex I of the mitochondrial respiratory chain in the expression of all three markers, and by extension the IFNγ signaling pathway. We report that the IFNγ response requires mitochondrial respiration, and APCs are unable to activate T cells upon genetic or chemical inhibition of complex I. These findings suggest a dichotomous metabolic dependency between IFNγ and toll-like receptor signaling, implicating mitochondrial function as a fulcrum of innate immunity.