Fingolimod targeting protein phosphatase 2A differently affects IL-33 induced IL-2 and IFN-γ production in CD8(+) lymphocytes

Eur J Immunol. 2016 Apr;46(4):941-51. doi: 10.1002/eji.201545805. Epub 2016 Jan 13.

Abstract

Multiple sclerosis patients are treated with fingolimod (FTY720), a prodrug that acts as an immune modulator. FTY720 is first phosphorylated to FTY720-P and then internalizes sphingosine-1-phosphate receptors, preventing lymphocyte sequestration. IL-33 is released from necrotic endothelial cells and contributes to MS severity by coactivating T cells. Herein we analyzed the influence of FTY720, FTY720-P, and S1P on IL-33 induced formation of IL-2 and IFN-γ, by using IL-33 receptor overexpressing EL4 cells, primary CD8(+) T cells, and splenocytes. EL4-ST2 cells released IL-2 after IL-33 stimulation that was inhibited dose-dependently by FTY720-P but not FTY720. In this system, S1P increased IL-2, and accordingly, inhibition of S1P producing sphingosine kinases diminished IL-2 release. In primary CD8(+) T cells and splenocytes IL-33/IL-12 stimulation induced IFN-γ, which was prevented by FTY720 but not FTY720-P, independently from intracellular phosphorylation. The inhibition of IFN-γ by nonphosphorylated FTY720 was mediated via the SET/protein phosphatase 2A (PP2A) pathway, since a SET peptide antagonist also prevented IFN-γ formation and the inhibition of IFN-γ by FTY720 was reversible by a PP2A inhibitor. While our findings directly improve the understanding of FTY720 therapy in MS, they could also contribute to side effects of FTY720 treatment, like progressive multifocal leukoencephalopathy, caused by an insufficient immune response to a viral infection.

Keywords: CD8+ T cells; Fingolimod (FTY720); IL-33; Multiple sclerosis; Protein phosphatase 2a (PP2A).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD8-Positive T-Lymphocytes / immunology*
  • Cell Line, Tumor
  • Female
  • Fingolimod Hydrochloride / metabolism
  • Fingolimod Hydrochloride / pharmacology*
  • Interferon-gamma / antagonists & inhibitors
  • Interferon-gamma / biosynthesis*
  • Interleukin-2 / biosynthesis*
  • Interleukin-33 / metabolism*
  • Lysophospholipids / antagonists & inhibitors
  • Lysophospholipids / metabolism
  • Mice
  • Mice, Inbred C57BL
  • Multiple Sclerosis / drug therapy
  • Oncogene Proteins / antagonists & inhibitors
  • Oncogene Proteins / metabolism
  • Organophosphates / pharmacology*
  • Phosphorylation
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors
  • Protein Phosphatase 2 / antagonists & inhibitors*
  • Protein Phosphatase 2 / metabolism
  • Sphingosine / analogs & derivatives*
  • Sphingosine / antagonists & inhibitors
  • Sphingosine / metabolism
  • Sphingosine / pharmacology
  • Spleen / cytology

Substances

  • FTY 720P
  • Il33 protein, mouse
  • Interleukin-2
  • Interleukin-33
  • Lysophospholipids
  • Oncogene Proteins
  • Organophosphates
  • SET protein, mouse
  • sphingosine 1-phosphate
  • Interferon-gamma
  • Phosphotransferases (Alcohol Group Acceptor)
  • sphingosine kinase
  • Protein Phosphatase 2
  • Fingolimod Hydrochloride
  • Sphingosine