Effect of miR-204 on proliferation and differentiation of osteoblasts in osteoporosis mice by Wnt signaling pathway and its mechanism

Objective To investigate the effect of miR-204 on the proliferation and differentiation of osteoblasts in osteoporosis mice by Wnt signaling pathway and its mechanism. Methods Female Kunming mice were divided into: control group, sham operation group and osteoporosis group. Ovariectomy mouse models were established and identified by bilateral ovariectomy; Mouse primary osteoblasts were extracted and identified; Cells was transfected and detected the miR-204 expression levels; MTT was used to detect the viability of each group of cells; Alkaline phosphatase (ALP) activity was detected in each cell group; Cell flowmetry was used to detect apoptosis in each group; Cell flowmetry was used to detect the activity of Caspase-3 in each group of cells; Interaction between miR-204, β-catenin and LRP-5 was detected by dual luciferase reporter gene. Western blot was used to detect the expression of Wnt signaling pathway-related proteins. Results The bone mineral density of the osteoporosis group was significantly lower than that of the control group and the sham operation group (P=0.007, P=0.057) , indicating that the osteoporosis mice were successfully modeled; The expression level of miR-204 was significantly increased in the miR-204 mimics group (P=0.007) , and decreased in the miR-204 inhibitor group (P=0.031) ; The activity of bone cell and ALP activity of miR-204 mimics increased (P=0.007, P=0.043) , and the activity of bone cell and ALP decreased by miR-204 inhibitor (P=0.007, P=0.035) ; The invasive ability of miR-204 mimics was significantly increased (P=0.006) , and the invasive ability of miR-204 inhibitor was decreased (P=0.036) ; The apoptosis ability and Caspase-3 activity of miR-204 mimics were decreased (P=0.041, P=0.045) , and the apoptosis ability and Caspase-3 activity of bone cells were enhanced by miR-204 inhibitor (P=0.005, P=0.039) ; There were targeting relationship between miR-204 and β-catenin, LRP-5. The expressions of β-catenin and LRP-5 protein in osteoblasts of miR-204 mimics were up-regulated (P=0.043, P=0.009) , and the expression of β-catenin and LRP-5 protein in bone cells of miR-204 inhibitor was down-regulated (P=0.041, P=0.032) . Conclusion miR-204 maybe promote the proliferation and differentiation of osteoblasts, activate Wnt signaling pathway, and has certain protective effect on osteoporosis. Key words: miR-204; Wnt signaling pathway; Osteoporosis mice; Osteoblasts; Proliferation