[ knockdown enhances osteogenic differentiation of adipose-derived mesenchymal stem cells and accelerates bone defect healing in mice].

OBJECTIVE

To investigate the role of high-mobility group AT-hook 2 (HMGA2) in osteogenic differentiation of adipose-derived mesenchymal stem cells (ADSCs) and the effect of knockdown for promoting bone defect repair.

METHODS

Bioinformatics studies using the GEO database and Rstudio software identified HMGA2 as a key factor in adipogenic-osteogenic differentiation balance of ADSCs. The protein-protein interaction network of HMGA2 in osteogenic differentiation was mapped using String and visualized with Cytoscape to predict the downstream targets of HMGA2. Primary mouse ADSCs (mADSCs) were transfected with siRNA, and the changes in osteogenic differentiation of the cells were evaluated using alkaline phosphatase staining and Alizarin red S staining. The expressions of osteogenic markers Runt-related transcription factor 2 (RUNX2), osteopontin (OPN), and osteocalcein (OCN) in the transfected cells were detected using RT-qPCR and Western blotting. In a mouse model of critical-sized calvarial defects, mADSCs with knockdown were transplanted into the defect, and bone repair was evaluated 6 weeks later using micro-CT scanning and histological staining.

RESULTS

GEO database analysis showed that expression was upregulated during adipogenic differentiation of ADSCs. Protein-protein interaction network analysis suggested that the potential HMGA2 targets in osteogenic differentiation of ADSCs included SMAD7, CDH1, CDH2, SNAI1, SMAD9, IGF2BP3, and ALDH1A1. In mADSCs, knockdown significantly upregulated the expressions of RUNX2, OPN, and OCN and increased cellular alkaline phosphatase activity and calcium deposition. In a critical-sized calvarial defect model, transplantation of mADSCs with knockdown significantly promoted new bone formation.

CONCLUSION

HMGA2 is a crucial regulator of osteogenic differentiation in ADSCs, and knockdown significantly promotes osteogenic differentiation of ADSCs and accelerates ADSCs-mediated bone defect repair in mice.