[ROLE OF FORKHEAD/FOX TRANSCRIPTION FACTOR 2 OVER-EXPRESSION IN REGULATING OSTEOGENIC DIFFERENTIATION OF BONE MARROW MESENCHYMAL STEM CELLS BY Wnt SIGNALING PATHWAYS].

OBJECTIVE: To investigate the role of the forkhead/Fox transcription factor 2 (Foxc2) over-expression in regulating osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) by Wnt-ß-catenin signaling pathways in vitro so as to provide the experimental basis for repairing osteonecrosis of the femoral head. METHODS: The recombinant lentivirus carrying green fluorescent protein (group A) or Foxc2 (group B) were used to transfect the fifth generation rabbit BMSCs, and untransfected BMSCs served as a control (group C). The cell viability was measured with water soluble tetrazolium-1 (WST-1) regent at 72 hours after transfection. After 2 weeks of transfection, the expression of ß-catenin in BMSCs was detected by real time fluorescence quantitative PCR, Western blot, and immunofluorescence staining. Meanwhile, the ß-catenin inhibitors XAV-939 (0, 0.1, and 1.0 µmol/L) was added in group B; at 2 weeks after osteogenic and adipogenic induction, the gene and protein expressions of collagen type I (COL I), osteocalcin (OCN), and peroxisome proliferator activated receptor gamma 2 (PPARγ-2) were detected by real time PCR and Western blot. RESULTS: WST-1 results showed that the cell viability of group B (130.85%±0.15%) was significantly higher than that of group A (100.45%±0.35%) (t=7.500, P=0.004) at 72 hours after transfection. At 2 weeks after transfection, the gene and protein expressions of ß-catenin in group B were significantly higher than those in group A (P<0.01). After XAV-939 was added in group B, the mRNA and protein expressions of OCN and COL I gradually decreased; the mRNA and protein expressions of PPARγ-2 significantly increased (P<0.05), showing a dose-dependent manner. CONCLUSIONS: The over-expression of Foxc2 gene in BMSCs may promote osteogenic differentiation by Wnt-ß-catenin signaling pathway.