Effect Of ERK5 Signaling Pathway On The Expression Of X-linked Inhibitor Of Apoptosis Protein XIAP In MC3T3-E1 Osteoblasts

Objective:To observe the expression of X-linked inhibitor of apoptosis protein(XIAP)in MC3T3-E1 osteoblasts mediated by fluid shear stress(FSS)through extracellular signal-regulated kinase 5(ERK5)signaling pathway,and to explore the role of ERK5 signaling pathway.Methods:In this sthdy,MC3T3-E1 cells with good growth were cultured and given one or more stimuli,such as FSS(12dyn/cm~2,45min),EGF(20ng/ml,10min),XMD8-92(5uM,1h,ERK5 specific inhibitor),ERK5-siRNA(specific inhibition of ERK5 expression).Western blot was used to detect ERK5,P-ERK5 and XIAP protein tables under different intervention measures.Results:The expression of P-ERK5 and XIAP in MC3T3-E1 osteoblasts was significantly increased by the fluid shear stress of 12 dyn/cm~2 for 45 min and 20ng/ml EGF for 10min.However,the expression of P-ERK5 and XIAP was blocked by 5umol/L XMD8-92 for 1h,and the expression of P-ERK5 and XIAP decreased.After transfection of ERK5-siRNA into MC3T3-E1 osteoblasts,ERK5 gene was knocked out,and the phosphorylation of ERK5 promoted by FSS was significantly inhibited.Compared with FSS alone,the expression of ERK5 and XIAP decreased.Conclusions:ERK5 was activated in MC3T3-E1 osteoblasts treated with20ng/ml EGF for 10 minutes and loaded with 12dyn/cm~2 FSS for 45 minutes.The expression of P-ERK5 and XIAP increased significantly.After pretreatment with5umol/L XMD8-92 for 1 hour,the effect weakened and the expression of P-ERK5 and XIAP decreased.The expression of ERK5 and XIAP decreased after ERK5-siRNA inhibited ERK5.It is suggested that ERK5 signaling pathway is involved in the regulation of XIAP expression in MC3T3-E1 osteoblasts.