Molecular mechanism of Wnt pathway in regulating osteogenic and chondrogenic differentiation of adipose stem cells

Abstract

Objective To explore the mechanism of Wingless-type MMTV integration site family (Wnt) pathway and SRY-related high mobility group-box gene 9 (Sox9) and Bone morphogenetic protein 2 (BMP-2) feedback regulation in regulating chondrogenic and osteogenic differentiation of adipose-derived stem cells (ADSCs). Methods The cartilage and osteogenic differentiation of ADSCs were stimulated by Lithium Chloride (LiCl) and Dickkopf related protein 1 (DKK-1). The markers of cartilage and osteogenic differentiation Collagen2a, Aggrecan, Core binding factor alphal 1 (Runx2), wingless-type MMTV integration site family, member 5A (Wnt5a) and Wnt pathway key proteins Sox9, BMP-2, β-catenin, Glycogen synthase kinase-3β (GSK-3β) were detected in early, middle and late stages. The full-length gene sequences of Sox9 and BMP-2 were transfected into ADSCs by lentivirus, respectively, then the expression levels of various indexes were detected again while stably expressed. Apply SPSS 20.0 statistical software for analysis and explore molecular mechanisms. Results During the cartilage differentiation of ADSCs, the Wnt pathway promotes its rapid proliferation and induces chondrogenic differentiation in the early and middle stages. The expression of Collagen 2a and Aggrecan was not significantly increased in the early, while significantly increased in the middle and late stages (t=1.484, 0.792, 8.598, 8.788, 3.333, 8.285, P 0.05). The expression of Runx2 was significantly increased in the middle and late stages (t=13.452, 12.148, 16.535, P<0.05), while the expression of Wnt5a was decreased (t=-4.017, -19.901, -7.181, P<0.05); overexpression expressed feedback activation of Wnt The pathway up-regulated β-catenin (0.26±0.08 vs. 0.64±0.05, t=8.789, P<0.05) and down-regulated Wnt5a (1.35±0.23 vs. 0.51±0.26, t=-5.233, P<0.05). The expression of BMP-2 was up-regulated in both groups (0.26±0.03 vs. 0.64±0.05; 0.47±0.03 vs. 1.15±0.15; 0.63±0.11 vs. 1.31±0.098, t=16.340, 8.750, 29.721, P<0.01). Conclusion The Wnt pathway regulates the cartilage and osteogenic differentiation of ADSCs by regulating Sox9 and BMP-2, respectively, and its regulatory mechanisms are distinct at different stages of differentiation. Key words: Adpose-derived stem cells; Chondrogenic differentiation; Osteogenic differentiation; Wingless-type MMTV integration site family/β-catenin signaling pathway