Sphingosine 1-phosphate (S1P)/S1P receptor 1 signaling regulates receptor activator of NF-κB ligand (RANKL) expression in rheumatoid arthritis

► MH7A cells and CD4+ T cells expressed S1P1 and RANKL. ► S1P increased RANKL expression in MH7A cells and CD4+ T cells. ► The effect of S1P in MH7A cells was inhibited by specific Gi/Go inhibitors.