Elevated Nuclear and Cytoplasmic FTY720-Phosphate in Mouse Embryonic Fibroblasts Suggests The Potential for Multiple Mechanisms in FTY720-Induced Neural Tube Defects

Nicole M. Gardner, Ronald T. Riley, Jency L. Showker, Kenneth A. Voss, Andrew J. Sachs, Joyce R. Maddox, Janee B. Gelineau-van Waes

Research output: Contribution to journalArticle

8 Scopus citations

Abstract

FTY720 (fingolimod) is a U.S. Food and Drug Administration-approved drug to treat relapsing remitting multiple sclerosis. FTY720 treatment in pregnant inbred LM/Bc mice results in approximately 60% of embryos having a neural tube defect (NTD). Sphingosine kinases (Sphk1, Sphk2) phosphorylate FTY720 in vivo to form the bioactive metabolite FTY720-1- phosphate (FTY720-P). Cytoplasmic FTY720-P is an agonist for 4 of the 5 sphingosine-1-phosphate (S1P) receptors (S1P1,3-5) and can also act as a functional antagonist of S1P1, whereas FTY720-P generated in the nucleus inhibits histone deacetylases (HDACs), leading to increased histone acetylation. This study demonstrates that treatment of LM/Bc mouse embryonic fibroblasts (MEFs) with FTY720 results in a significant accumulation of FTY720-P in both the cytoplasmic and nuclear compartments. Elevated nuclear FTY720-P is associated with decreased HDAC activity and increased histone acetylation at H3K18 and H3K23 in LM/Bc MEFs. Treatment of LM/Bc MEFs with FTY720 and a selective Sphk2 inhibitor, ABC294640, significantly reduces the amount of FTY720-P that accumulates in the nucleus. The data provide insight into the relative amounts of FTY720-P generated in the nuclear versus cytoplasmic subcellular compartments after FTY720 treatment and the specific Sphk isoforms involved. The results of this study suggest that FTY720-induced NTDs may involve multiple mechanisms, including: (1) sustained and/or altered S1P receptor activation and signaling by FTY720-P produced in the cytoplasm and (2) HDAC inhibition and histone hyperacetylation by FTY720-P generated in the nucleus that could lead to epigenetic changes in gene regulation.

Original languageEnglish (US)
Article numberkfv321
Pages (from-to)161-168
Number of pages8
JournalToxicological Sciences
Volume150
Issue number1
DOIs
StatePublished - Mar 1 2016

All Science Journal Classification (ASJC) codes

  • Toxicology

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