Activation of toll-like receptor 2 prevents suppression of T-cell interferon γ production by modulating p38/extracellular signal-regulated kinase pathways following alcohol and burn injury

Mol Med. 2012 Sep 7;18(1):982-91. doi: 10.2119/molmed.2011.00513.

Abstract

Recent studies indicate that toll-like receptors (TLRs) are expressed on T cells and that these receptors directly or indirectly activate the adaptive immune system. We have shown previously that acute alcohol/ethanol (EtOH) intoxication combined with burn injury suppresses mesenteric lymph node (MLN) T-cell interleukin-2 (IL-2) and interferon γ (IFN-γ) production. We examined whether direct stimulation of T cells with TLR2, 4, 5 and 7 agonists modulates CD3-mediated T-cell IL-2/IFN-γ release following EtOH and burn injury. Male mice were gavaged with EtOH (2.9 gm/kg) 4 h prior to receiving an ~12.5% total body surface area sham or full-thickness burn injury. Animals were killed on d 1 after injury and T cells were purified from MLN and spleens. T cells were cultured with plate-bound anti-CD3 in the presence or absence of various TLR ligands. Although TLR2, 4 and 5 agonists potentiate anti-CD3-dependent IFN-γ by T cells, the TLR2 agonist alone induced IFN-γ production independent of CD3 stimulation. Furthermore, T cells were treated with inhibitors of myeloid differentiation primary response protein 88 (MyD88), TIR domain-containing adaptor protein (TIRAP), p38 and/or extracellular signal-regulated kinase (ERK) to determine the mechanism by which TLR2 mediates IL-2/IFN-γ production. IL-2 was not influenced by TLR agonists. MyD88 and TIRAP inhibitory peptides dose-dependently diminished the ability of T cells to release IFN-γ. p38 and ERK inhibitors also abolished TLR2-mediated T-cell IFN-γ. Together, our findings suggest that TLR2 directly modulates T-cell IFN-γ production following EtOH and burn injury, independent of antigen-presenting cells. Furthermore, we demonstrated that MyD88/TIRAP-dependent p38/ERK activation is critical to TLR2-mediated T-cell IFN-γ release following EtOH and burn injury.

Publication types

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

MeSH terms

  • Alcoholic Intoxication / complications
  • Alcoholic Intoxication / enzymology
  • Alcoholic Intoxication / immunology*
  • Animals
  • Burns / complications
  • Burns / enzymology
  • Burns / immunology*
  • Extracellular Signal-Regulated MAP Kinases / antagonists & inhibitors
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Interferon-gamma / biosynthesis*
  • Interleukin-2 / biosynthesis
  • MAP Kinase Signaling System / drug effects
  • Male
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Myeloid Differentiation Factor 88 / metabolism
  • Phosphorylation / drug effects
  • Protein Kinase Inhibitors / pharmacology
  • Receptors, Interleukin-1 / metabolism
  • Spleen / immunology
  • Spleen / pathology
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / enzymology*
  • T-Lymphocytes / immunology
  • Toll-Like Receptor 2 / agonists
  • Toll-Like Receptor 2 / metabolism*
  • p38 Mitogen-Activated Protein Kinases / antagonists & inhibitors
  • p38 Mitogen-Activated Protein Kinases / metabolism*

Substances

  • Interleukin-2
  • Membrane Glycoproteins
  • Myeloid Differentiation Factor 88
  • Protein Kinase Inhibitors
  • Receptors, Interleukin-1
  • TIRAP protein, mouse
  • Toll-Like Receptor 2
  • Interferon-gamma
  • Extracellular Signal-Regulated MAP Kinases
  • p38 Mitogen-Activated Protein Kinases