title: Mechanical Stress Regulates Osteogenesis and Adipogenesis of Rat Mesenchymal Stem Cells through PI3K/Akt/GSK-3β/β-Catenin Signaling Pathway.
abstract: Osteogenesis and adipogenesis of bone marrow mesenchymal stem cells (BMSCs) are regarded as being of great importance in the regulation of bone remodeling. In this study, rat BMSCs were exposed to different levels of cyclic mechanical stress generated by liquid drops and cultured in general medium or adipogenic medium. Markers of osteogenic (Runx2 and Collagen I) and adipogenic (C/EBPα, PPARγ, and lipid droplets) differentiation were detected using Western blot and histological staining. The protein levels of members of the phosphatidylinositol 3-kinase (PI3K)/Akt/glycogen synthase kinase 3β(GSK-3β)/β-catenin signaling pathway were also examined. Results showed that small-magnitude stress significantly upregulated Runx2 and Collagen I and downregulated PPARγand C/EBPαexpression in BMSCs cultured in adipogenic medium, while large-magnitude stress reversed the effect when compared with unloading groups. The PI3K/Akt signaling pathway could be strongly activated by mechanical stimulation; however, large-magnitude stress led to decreased activation of the signaling pathway when compared with small-magnitude stress. Activation ofβ-catenin with LiCl led to increased expression of Runx2 and Collagen I and reduction of C/EBPαand PPARγexpression in BMSCs. Inhibition of PI3K/Akt signaling partially blocked the expression ofβ-catenin. Taken together, our results indicate that mechanical stress-regulated osteogenesis and adipogenesis of rat BMSCs are mediated, at least in part, by the PI3K/Akt/GSK-3β/β-catenin signaling pathway.
authors.affiliation: Department of Orthopedics, Third Affiliated Hospital, PLA Second Military Medical University, Shanghai 200433, China.
authors.forename: Fanglong
authors.initials: F
authors.lastname: Song
authors.affiliation: Department of Orthopedics, Third Affiliated Hospital, PLA Second Military Medical University, Shanghai 200433, China.
authors.forename: Dawei
authors.initials: D
authors.lastname: Jiang
authors.affiliation: Department of Orthopedics, Third Affiliated Hospital, PLA Second Military Medical University, Shanghai 200433, China.
authors.forename: Tianchen
authors.initials: T
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Third Affiliated Hospital, PLA Second Military Medical University, Shanghai 200433, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Third Affiliated Hospital, PLA Second Military Medical University, Shanghai 200433, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Lou
authors.affiliation: Department of Orthopedics, Third Affiliated Hospital, PLA Second Military Medical University, Shanghai 200433, China.
authors.forename: Yinquan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Orthopedics, Third Affiliated Hospital, PLA Second Military Medical University, Shanghai 200433, China.
authors.forename: Hui
authors.initials: H
authors.lastname: Ma
authors.affiliation: Department of Orthopedics, Third Affiliated Hospital, PLA Second Military Medical University, Shanghai 200433, China.
authors.forename: Yifan
authors.identifier: 0000-0002-5856-6643
authors.initials: Y
authors.lastname: Kang
mesh_terms: D050156:Adipogenesis; D000818:Animals; D002454:Cell Differentiation; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism*; D040542:Mechanotransduction, Cellular; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D010012:Osteogenesis; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D051176:beta Catenin; D019869:Phosphatidylinositol 3-Kinases; D000071679:Glycogen Synthase Kinase 3 beta; C000605508:Gsk3b protein, rat; D051057:Proto-Oncogene Proteins c-akt