Effects of fingolimod on sphingosine-1-phosphate signal in osteoclasts / 中华创伤骨科杂志

ABSTRACT

Objective To study the effects of fingolimod (FTY720) on the sphingosine-1-phosphate (S1P) signaling pathway in osteoclasts.Methods Murine RAW 264.7 macrophages were induced into osteoclasts by dexamethasone and 1 α,25-(OH)2VitD3 and identified by tartrate resistant acid phosphatase Trp staining.After the osteoclasts were divided into 2 groups,the experimental group was treated with 400 ng/mL FTY720-P while the control group was not.The signal expression of extracellular signal-regulated kinase 1 (ERK1),caspase9 and protein kinase(PKC) in the downstream of S1 P pathway was detected at the gene and protein levels,and the expression of bone morphogenetic protein-2(BMP-2) and transforming growth factor-β1 (TGF-β1),which are closely related to bone reconstruction,was detected.Results The RAW264.7 cells were successfully induced into osteoclasts identified by trataric acid phosphatase staining kit (TRAP).The expression of S1PR1 in osteoclasts was higher than that in other S1PRs.After culture for 48 hours,the expression of PKC mRNA in the experimental group was significantly lower than that in the control group while the expression of BMP-2 mRNA and TGF-[β1 mRNA was significantly increased in the experimental group than in the control group (P ＜ 0.05).However,there were no significant differences in expression of ERK1 mRNA or caspase9 mRNA between the 2 groups(P ＞ 0.05).Conclusions FTY720-P can affect the expression of PKC signal in the downstream of osteoclasts by affecting S1P signaling pathway,mainly by binding to S1PR1 signal pathway,and can also promote the expression of TGF-[β1 and BMP-2 in osteoclasts,ultimately affecting the function of osteoclasts.