Glatiramer acetate triggers PI3Kδ/Akt and MEK/ERK pathways to induce IL-1 receptor antagonist in human monocytes

Proc Natl Acad Sci U S A. 2010 Oct 12;107(41):17692-7. doi: 10.1073/pnas.1009443107. Epub 2010 Sep 27.

Abstract

Glatiramer acetate (GA), an immunomodulator used in multiple sclerosis (MS) therapy, induces the production of secreted IL-1 receptor antagonist (sIL-1Ra), a natural inhibitor of IL-1β, in human monocytes, and in turn enhances sIL-1Ra circulating levels in MS patients. GA is a mixture of peptides with random Glu, Lys, Ala, and Tyr sequences of high polarity and hydrophilic nature that is unlikely to cross the blood-brain barrier. In contrast, sIL-1Ra crosses the blood-brain barrier and, in turn, may mediate GA anti-inflammatory activities within the CNS by counteracting IL-1β activities. Here we identify intracellular signaling pathways induced by GA that control sIL-1Ra expression in human monocytes. By using kinase knockdown and specific inhibitors, we demonstrate that GA induces sIL-1Ra production via the activation of PI3Kδ, Akt, MEK1/2, and ERK1/2, demonstrating that both PI3Kδ/Akt and MEK/ERK pathways rule sIL-1Ra expression in human monocytes. The pathways act in parallel upstream glycogen synthase kinase-3α/β (GSK3α/β), the knockdown of which enhances sIL-1Ra production. Together, our findings demonstrate the existence of signal transduction triggered by GA, further highlighting the mechanisms of action of this drug in MS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Gene Knockdown Techniques
  • Glatiramer Acetate
  • Glycogen Synthase Kinase 3 / genetics
  • Glycogen Synthase Kinase 3 / metabolism
  • Humans
  • Interleukin 1 Receptor Antagonist Protein / immunology
  • Interleukin 1 Receptor Antagonist Protein / metabolism*
  • Mitogen-Activated Protein Kinase Kinases / metabolism
  • Monocytes / immunology
  • Multiple Sclerosis / drug therapy*
  • Multiple Sclerosis / immunology*
  • Peptides / pharmacology*
  • Phosphatidylinositol 3-Kinases / metabolism
  • Proto-Oncogene Proteins c-akt / metabolism
  • Signal Transduction / drug effects*
  • Signal Transduction / immunology

Substances

  • Interleukin 1 Receptor Antagonist Protein
  • Peptides
  • Glatiramer Acetate
  • Phosphatidylinositol 3-Kinases
  • Proto-Oncogene Proteins c-akt
  • Glycogen Synthase Kinase 3
  • glycogen synthase kinase 3 alpha
  • Mitogen-Activated Protein Kinase Kinases