EphrinB2 / EphB4 Mediates The Regulation Mechanism Of EPO On Osteoclasts

Objectives: The aim of this study was to investigate how the activation of osteoclastcan be regulated by EPO.Considering there are many differences between primary cell andin vitro cells, invitro cell lines have good stability and is very advantageous, This studyusing the RAW264.7mouse monocyte/macrophage cell line as an osteoclast precursor.The role of erythropoietin (EPO) and Epo receptor (EpoR) signaling pathways forproduction of red blood-cell has been extensively studied. And EPO plays a critical role inthe formation, proliferation and maturation of bone cells. However, little is known abouthow EPO/EpoR signaling effects on osteoclast differentiation.In another way this studywas to investigate how the activation of osteoclast can be regulated by EPO.Methods:Some RAW264.7cells were treated with rhEpo and the receptor activator ofnuclear factor-κ B (RANK) ligand (RANKL) for an indicated period of time. Other cells weretreated with rhEPO and the receptor activator of nuclear factor-κ B (RANK) ligand (RANKL)for an indicated period of time.The numbers of tartrate-resistant acid phosphatase (TRAP)staining positive, multinucleated cells after5~9days.The levels of Epor,Nfatc1,efnb2, matrixmetalloproteinase-9(Mmp-9), cathepsin K was measured by semi-quantitative real-time PCR..Result:We demonstrated that inhibition of EpoR use shRNA was decreases Nfatc1,efnb2and creases Ctsk,Mmp9expression by EPO stimulation. we used osteoblast-osteoclastcoculture assays, addition of EphB4-Fc. Treatment of osteoclast with EphB4-Fc resulted ingreater inhibition of osteoclast formation.Finally,the results suggest that EPO/EpoR signals control osteoclast differentiation.We found that the reverse signaling inhibition of decrease Nfatc1,efnb2expression byEPO.