Erk5Kianse Participated In BMP9-Induced Osteogenic Differentiation Of Mesenchynal Stem Cells

Objective： Analysis the functional role of ERK5kinase inBMP-9-induced osteogenic differentiation of C3H10T1/2mesenchymalstem cells MC3T3the murine osteoblastic cell C2C12the murinemyoblastic cell MEF the murine embryonic fibroblast cells.Methods:C3H10T1/2cells were infected by recombinant adenovirusexpressing BMP9, then the total protein level and phosphorylated form ofERK5kinase were determined by Western blot. After treatment C3H10T1/2cells with ERK5specific inhibitor S1531the early osteogenic marker ALPactivity was detected by quantitative and staining assay the late osteogenicmarker calcium deposition was determined by Alizarin Red S staining,expression level of Runx2and Smad7were analyzed by Real time PCR.expression level of Id-1，Id-2，Id-3，CTGFmRNA were analyzed byRT-PCR.expression level of Runx2，Smad1/5/8，OPN，OCN were analyzedby western blot.expression level of Smad1/5/8was analyzed by luciferaseactivity.Results: BMP9did not change total protein level of ERK5, however,BMP9increased the phosphorylated form of ERK5kinase. ERK5specific inhibitor S1531dose-dependently decreased ALP activity inducedby BMP9of C3H10T1/2、MC3T3、C2C12、MEFcells. Furthermore, S1531dose-dependently inhibited calcium deposition, reduced BMP-9-inducedexpressions of Runx2，Id-1，Id-2，Id-3，CTGF，Smad1/5/8，OPN，OCNand Smad7.Conclusion: The ERK5kianse may invovlve in BMP9inducedosteoblast commitment of C3H10T1/2、 MC3T3、 C2C12、 MEFmesenchymal stem cells.