Protein tyrosine phosphatase SHP-1 modulates osteoblast differentiation through direct association with and dephosphorylation of GSK3β.
SHP-1, the Src homology-2 (SH2) domain-containing phosphatase 1, is a cytosolic protein-tyrosine phosphatase (PTP) predominantly expressed in hematopoietic-derived cells. Previous studies have focused on the involvement of SHP-1 in osteoclastogenesis. Using primary cultured mouse fetal calvaria-derived osteoblasts as a model, this study aims to investigate the effects of SHP-1 on differentiation and mineralization of osteoblasts and elucidate the signaling pathways responsible for these effects. We found that osteoblasts treated by osteogenic media showed significant increase in SHP-1 expression, which contributed to osteoblastic differentiation and mineralization. Using immunoprecipitation assay, we found that a direct association between SHP-1 and glycogen synthase kinase (GSK)-3β could be detected in differentiated osteoblasts and was significantly inhibited by SHP-1 inhibitor NSC87877. Inhibition of SHP-1 activated GSK3β, thereby leading to suppression of osteoblast differentiation and mineralization, which could be rescued by the inhibitor of GSK3β. In addition, we found that rosiglitazone (RSG) treatment led to significant decrease in SHP-1 expression. Overexpression of SHP-1 reversed RSG-induced GSK3β activation, thus rescuing the inhibitory effect of RSG on osteoblast differentiation and mineralization. These findings suggest that protein tyrosine phosphatase SHP-1 may act as a positive regulator of osteoblast differentiation through direct association with and dephosphorylation of GSK3β. Downregulation of SHP-1 may contribute to RSG-induced inhibition of mouse calvaria osteoblast differentiation by activating GSK3β-dependent pathway.
Department of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai, 200433, China.
Xiao-Lu
XL
Tang
Department of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai, 200433, China.
Chang-Nan
CN
Wang
Department of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai, 200433, China. Electronic address: xiaoyanzhu@smmu.edu.cn.
Xiao-Yan
XY
Zhu
Department of Physiology and the Key Laboratory of Molecular Neurobiology of Ministry of Education, Second Military Medical University, Shanghai, 200433, China. Electronic address: nixin@smmu.edu.cn.
Xin
X
Ni
D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D002478:Cells, Cultured; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005333:Fetus / Q000166:cytology; D055785:Gene Knockdown Techniques; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism*; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D051379:Mice; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology*; D010766:Phosphorylation / Q000187:drug effects; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000378:metabolism*; D011804:Quinolines; D000077154:Rosiglitazone; D012886:Skull / Q000166:cytology; D045162:Thiazolidinediones / Q000494:pharmacology; D015854:Up-Regulation / Q000187:drug effects
D007211:Indoles; D008301:Maleimides; C512715:NSC-87877; D047428:Protein Kinase Inhibitors; D011804:Quinolines; C417521:SB 216763; D045162:Thiazolidinediones; D000077154:Rosiglitazone; D000071679:Glycogen Synthase Kinase 3 beta; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6
GSK3β; Osteoblast; SHP-1