Act1 is a negative regulator in T and B cells via direct inhibition of STAT3

Nat Commun. 2018 Jul 16;9(1):2745. doi: 10.1038/s41467-018-04974-3.

Abstract

Although Act1 (adaptor for IL-17 receptors) is necessary for IL-17-mediated inflammatory responses, Act1- (but not Il17ra-, Il17rc-, or Il17rb-) deficient mice develop spontaneous SLE- and Sjögren's-like diseases. Here, we show that Act1 functions as a negative regulator in T and B cells via direct inhibition of STAT3. Mass spectrometry analysis detected an Act1-STAT3 complex, deficiency of Act1 (but not Il17ra-, Il17rc-, or Il17rb) results in hyper IL-23- and IL-21-induced STAT3 activation in T and B cells, respectively. IL-23R deletion or blockade of IL-21 ameliorates SLE- and Sjögren's-like diseases in Act1-/- mice. Act1 deficiency results in hyperactivated follicular Th17 cells with elevated IL-21 expression, which promotes T-B cell interaction for B cell expansion and antibody production. Moreover, anti-IL-21 ameliorates the SLE- and Sjögren's-like diseases in Act1-deficient mice. Thus, IL-21 blocking antibody might be an effective therapy for treating SLE- and Sjögren's-like syndrome in patients containing Act1 mutation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / deficiency
  • Adaptor Proteins, Signal Transducing / genetics*
  • Adaptor Proteins, Signal Transducing / immunology
  • Animals
  • Antibodies, Monoclonal / pharmacology
  • B-Lymphocytes / drug effects
  • B-Lymphocytes / immunology*
  • B-Lymphocytes / pathology
  • Cell Differentiation
  • Disease Models, Animal
  • Female
  • Gene Expression Regulation
  • Interleukin-17 / genetics
  • Interleukin-17 / immunology
  • Interleukins / antagonists & inhibitors
  • Interleukins / genetics*
  • Interleukins / immunology
  • Leukocytes, Mononuclear / drug effects
  • Leukocytes, Mononuclear / immunology
  • Leukocytes, Mononuclear / pathology
  • Lupus Erythematosus, Systemic / drug therapy
  • Lupus Erythematosus, Systemic / genetics*
  • Lupus Erythematosus, Systemic / immunology
  • Lupus Erythematosus, Systemic / pathology
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Primary Cell Culture
  • Receptors, Interleukin / deficiency
  • Receptors, Interleukin / genetics
  • Receptors, Interleukin / immunology
  • Receptors, Interleukin-17 / deficiency
  • Receptors, Interleukin-17 / genetics
  • Receptors, Interleukin-17 / immunology
  • STAT3 Transcription Factor / genetics*
  • STAT3 Transcription Factor / immunology
  • Signal Transduction
  • Sjogren's Syndrome / drug therapy
  • Sjogren's Syndrome / genetics*
  • Sjogren's Syndrome / immunology
  • Sjogren's Syndrome / pathology
  • Spleen
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / pathology

Substances

  • Adaptor Proteins, Signal Transducing
  • Antibodies, Monoclonal
  • Il17a protein, mouse
  • Il17ra protein, mouse
  • Il17rb protein, mouse
  • Il17rc protein, mouse
  • Interleukin-17
  • Interleukins
  • Receptors, Interleukin
  • Receptors, Interleukin-17
  • STAT3 Transcription Factor
  • Stat3 protein, mouse
  • Traf3ip2 protein, mouse
  • interleukin-23 receptor, mouse
  • interleukin-21