IL-6 transsignalling modulates the early effector phase of EAE and targets the blood-brain barrier

J Neuroimmunol. 2008 Dec 15;205(1-2):64-72. doi: 10.1016/j.jneuroim.2008.09.007. Epub 2008 Oct 23.

Abstract

Interleukin-6 (IL-6) plays a crucial role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE). It exerts its cellular effects by a membrane-bound IL-6 receptor (IL-6R), or, alternatively, by forming a complex with the soluble IL-6R (sIL-6R), a process named IL-6 transsignalling. Here we investigate the role of IL-6 transsignalling in myelin basic protein (MBP)-induced EAE in the Lewis rat. In vivo blockade of IL-6 transsignalling by the injection of a specifically designed gp130-Fc fusion protein significantly delayed the onset of adoptively transferred EAE in comparison to control rats injected with PBS or isotype IgG. Histological evaluation on day 3 after immunization revealed reduced numbers of T cells and macrophages in the lumbar spinal cord of gp130-Fc treated rats. At the same time, blockade of IL-6 transsignalling resulted in a reduced expression of vascular cell adhesion molecule-1 on spinal cord microvessels while experiments in cell culture failed to show a direct effect on the regulation of endothelial adhesion molecules. In experiments including active EAE and T cell culture, inhibition of IL-6 transsignalling mildly increased T cell proliferation, but did not change severity of active MBP-EAE or regulate Th1/Th17 responses. We conclude that IL-6 transsignalling may play a role in autoimmune inflammation of the CNS mainly by regulating early expression of adhesion molecules, possibly via cellular networks at the blood-brain barrier.

MeSH terms

  • Animals
  • Blood-Brain Barrier / physiopathology*
  • CHO Cells
  • Cell Proliferation
  • Cells, Cultured
  • Cricetinae
  • Cricetulus
  • Cytokine Receptor gp130 / immunology
  • Cytokine Receptor gp130 / metabolism
  • Cytokines / immunology
  • Cytokines / metabolism
  • Disease Models, Animal
  • Encephalomyelitis, Autoimmune, Experimental / chemically induced
  • Encephalomyelitis, Autoimmune, Experimental / pathology*
  • Encephalomyelitis, Autoimmune, Experimental / physiopathology
  • Enzyme-Linked Immunosorbent Assay / methods
  • Female
  • Guinea Pigs
  • Interleukin-6 / metabolism*
  • Myelin Basic Protein / immunology
  • Rats
  • Rats, Inbred Lew
  • Receptors, Interleukin-6 / metabolism*
  • Signal Transduction / physiology*
  • Spinal Cord / metabolism
  • T-Lymphocytes / drug effects
  • T-Lymphocytes / immunology
  • T-Lymphocytes / metabolism
  • Time Factors

Substances

  • Cytokines
  • Interleukin-6
  • Myelin Basic Protein
  • Receptors, Interleukin-6
  • Cytokine Receptor gp130