Pharmacological Inhibition of Bromodomain Proteins Suppresses Retinal Inflammatory Disease and Downregulates Retinal Th17 Cells [AUTOIMMUNITY]

Abstract

Experimental autoimmune uveitis (EAU), in which CD4+ Th1 and/or Th17 cells are immunopathogenic, mimics various clinical features of noninfectious uveitis in humans. The impact of bromodomain extraterminal (BET) inhibitors on Th17 cell function was studied in a mouse model of EAU in vivo and in mouse and human Th17 cells in vitro. Two BET inhibitors (GSK151 and JQ1) were able to ameliorate the progression of inflammation in EAU and in mouse CD4+ T cells in vitro, downregulating levels of Th17 cells. Additionally, the uveitogenic capacity of Th17 cells to transfer EAU was abrogated by BET inhibitors in an adoptive transfer model. In human CD4+ T cells, a 5-d exposure to BET inhibitors was accompanied by a significant downregulation of Th17-associated genes IL-17A, IL-22, and retinoic acid–related orphan receptor γt. However, in vitro, the inhibitors had no effect on already polarized Th17 cells. The key finding is that, in response to BET inhibitors, Th17-enriched cultures developed a regulatory phenotype, upregulated FOXP3 expression and IL-10 secretion, and lost pathogenicity in vivo. We conclude that BET targeting of Th17 cells is a potential therapeutic opportunity for a wide range of inflammatory and autoimmune diseases, including uveitis.

Footnotes

  • This work was supported in part by a collaborative grant from GlaxoSmithKline Ophthalmology, Stevenage, U.K.

  • The online version of this article contains supplemental material.

  • Abbreviations used in this article:

    BET
    bromodomain extraterminal
    EAU
    experimental autoimmune uveitis
    IRBP
    interphotoreceptor retinoid-binding protein
    pLN
    peripheral lymph node
    rh
    recombinant human
    rm
    recombinant murine
    ROR
    retinoic acid–related orphan receptor
    Treg
    T regulatory.
  • Received April 26, 2016.
  • Accepted November 24, 2016.

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