SDF-1/CXCR4 axis promotes osteogenic differentiation of BMSCs through the JAK2/STAT3 pathway.

Introduction: This study aimed to investigate the effects of stromal cell-derived factor-1 (SDF-1) and activation of its receptor, chemokine receptor 4 (CXCR4), on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and the key signaling mechanisms involved in these effects.

Material and methods: BMSCs were treated with 100 μg/L SDF-1 and cultured in osteogenic medium for 7 days. RT-qPCR and western blotting were used to detect the protein and mRNA levels of Janus kinase 2 (JAK2), signal transducer and activator of transcription 3 (STAT3), Runt-related transcription factor 2 (Runx2), and osteocalcin (OCN). Alizarin-red staining was used to detect the mineralization-inducing ability of the cells.

Results: After BMSCs were treated with SDF-1, the levels of JAK2 mRNA, STAT3 mRNA, and protein phosphorylation increased, the number of mineralized nodules of BMSCs increased, and the osteogenic-differentiation ability was enhanced. In addition, after BMSCs were treated with an inhibitor of JAK2 phosphorylation, the levels of JAK2, STAT3, Runx2, and OCN decreased significantly, the number of mineralized nodules of BMSCs also decreased, and the osteogenic-differentiation ability decreased. The inhibition of CXCR4-treated BMSCs further confirmed that SDF-1/CXCR4 activated JAK2/STAT3 to regulate the osteogenic differentiation of BMSCs.

Conclusions: SDF-1/CXCR4 promoted the osteogenic differentiation of BMSCs through JAK2/STAT3 activation.