High levels of GSK-3β signalling reduce osteogenic differentiation of stem cells in osteonecrosis of femoral head.

Osteonecrosis of the femoral head (ONFH) is a common but intractable disease. In this study, we investigated the mechanisms regulating alterations in mesenchymal stem cell (MSC) differentiation in ONFH. Five patients who were diagnosed with ONFH were enrolled in this study. Bone MSCs (BMSCs) were isolated from the osteonecrotic zone in the femoral head (FH-pMSCs) and from the normal zone in the pelvis (hMSCs) of the same patient. Morphology, cell proliferation and expression of mediators of the Wnt signalling pathway were evaluated. There were significant differences in cell proliferation and expression of surface markers between the two populations of cells. FH-pMSCs exhibited significantly lower osteogenic differentiation compared with hMSCs (P < 0.0001). Dissection of the Wnt pathway showed that FH-pMSCs had significantly higher GSK3β expression compared with hMSCs (P < 0.001). Addition of LiCl, a GSK3β inhibitor, significantly increased osteogenic differentiation in FH-pMSCs, suggesting a relationship between the microenvironment and regulation of stem cell behaviour in ONFH. FH-pMSCs also exhibited significant downregulation of other mediators of the Wnt signalling pathway, including runx2 and β-catenin. Our data suggested that mediators of the Wnt signalling pathway, such as GSK3β could be important therapeutic targets for early-stage ONFH.