Fingolimod induces neuroprotective factors in human astrocytes

Background: fingolimod (fty720) is the first sphingosine-1-phosphate (s1p) receptor modulator approved for the treatment of multiple sclerosis. the phosphorylated active metabolite fty720-phosphate (fty-p) interferes with lymphocyte trafficking. in addition,it accumulates in the cns and reduces brain atrophy in multiple sclerosis (ms),and neuroprotective effects are hypothesized. methods: human primary astrocytes as well as human astrocytoma cells were stimulated with fty-p or s1p. we analyzed gene expression by a genome-wide microarray and validated induced candidate genes by quantitative pcr (qpcr) and elisa. to identify the s1p-receptor subtypes involved,we applied a membrane-impermeable s1p analog (dihydro-s1p),receptor subtype specific agonists and antagonists,as well as rnai silencing. results: fty-p induced leukemia inhibitory factor (lif),interleukin 11 (il11),and heparin-binding egf-like growth factor (hbegf) mrna,as well as secretion of lif and il11 protein. in order to mimic an inflammatory milieu as observed in active ms lesions,we combined fty-p application with tumor necrosis factor (tnf). in the presence of this key inflammatory cytokine,fty-p synergistically induced lif,hbegf,and il11 mrna,as well as secretion of lif and il11 protein. tnf itself induced inflammatory,b-cell promoting,and antiviral factors (cxcl10,baff,mx1,and oas2). their induction was blocked by fty-p. after continuous exposure of cells to fty-p or s1p for up to 7days,the extent of induction of neurotrophic factors and the suppression of tnf-induced inflammatory genes declined but was still detectable. the induction of neurotrophic factors was mediated via surface s1p receptors 1 (s1pr1) and 3 (s1pr3). conclusions: we identified effects of fty-p on astrocytes,namely induction of neurotrophic mediators (lif,hbegf,and il11) and inhibition of tnf-induced inflammatory genes (cxcl10,baff,mx1,and oas2). this supports the view that a part of the effects of fingolimod may be mediated via astrocytes. © 2015 hoffmann et al.