The phosphorylated form of FTY720 activates PP2A, represses inflammation and is devoid of S1P agonism in A549 lung epithelial cells

Sci Rep. 2016 Nov 16:6:37297. doi: 10.1038/srep37297.

Abstract

Protein phosphatase 2A (PP2A) activity can be enhanced pharmacologically by PP2A-activating drugs (PADs). The sphingosine analog FTY720 is the best known PAD and we have shown that FTY720 represses production of pro-inflammatory cytokines responsible for respiratory disease pathogenesis. Whether its phosphorylated form, FTY720-P, also enhances PP2A activity independently of the sphingosine 1-phosphate (S1P) pathway was unknown. Herein, we show that FTY720-P enhances TNF-induced PP2A phosphatase activity and significantly represses TNF-induced interleukin 6 (IL-6) and IL-8 mRNA expression and protein secretion from A549 lung epithelial cells. Comparing FTY720 and FTY720-P with S1P, we show that unlike S1P, the sphingosine analogs do not induce cytokine production on their own. In fact, FTY720 and FTY720-P significantly repress S1P-induced IL-6 and IL-8 production. We then examined their impact on expression of cyclooxygenase 2 (COX-2) and resultant prostaglandin E2 (PGE2) production. S1P did not increase production of this pro-inflammatory enzyme because COX-2 mRNA gene expression is NF-κB-dependent, and unlike TNF, S1P did not activate NF-κB. However, TNF-induced COX-2 mRNA expression and PGE2 secretion is repressed by FTY720 and FTY720-P. Hence, FTY720-P enhances PP2A activity and that PADs can repress production of pro-inflammatory cytokines and enzymes in A549 lung epithelial cells in a manner devoid of S1P agonism.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • A549 Cells
  • Cyclooxygenase 2 / genetics
  • Cyclooxygenase 2 / metabolism
  • Dinoprostone / metabolism
  • Enzyme Activation / drug effects
  • Epithelial Cells / drug effects*
  • Epithelial Cells / metabolism
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Inflammation / genetics
  • Inflammation / metabolism
  • Inflammation / prevention & control*
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Interleukin-8 / genetics
  • Interleukin-8 / metabolism
  • Lung / pathology
  • Lysophospholipids / pharmacology
  • Organophosphates / pharmacology*
  • Protein Phosphatase 2 / metabolism*
  • Sphingosine / analogs & derivatives*
  • Sphingosine / pharmacology
  • Tumor Necrosis Factor-alpha / pharmacology

Substances

  • FTY 720P
  • Interleukin-6
  • Interleukin-8
  • Lysophospholipids
  • Organophosphates
  • Tumor Necrosis Factor-alpha
  • sphingosine 1-phosphate
  • Cyclooxygenase 2
  • Protein Phosphatase 2
  • Dinoprostone
  • Sphingosine