Figure 1.

Sclerostin inhibits BMP2-induced osteoblast differentiation without affecting canonical BMP signaling in C3H10T1/2 cells. (a) C3H10T1/2 cells in osteogenic medium were pre-incubated with sclerostin (SOST, 5 μg ml⁻¹) or its vehicle (Veh) for 15 min and stimulated with BMP2 (50 ng ml⁻¹) or its vehicle (c) for 48 h before measurements of ALP activity. (b) Expression of osteoblast marker genes in the same conditions as for (a). (c) Evaluation of SMAD transcriptional activity in C3H10T1/2 cells pre-incubated with vehicle, 10 μg ml⁻¹ sclerostin or 250 ng ml⁻¹ noggin and stimulated with 25 ng ml⁻¹ BMP2 or its vehicle for 16 h. (d) Western blot analyses of SMAD1/5 phosphorylation in C3H10T1/2 cells pre-treated with 10 μg ml⁻¹ sclerostin or its vehicle and stimulated with 25 ng ml⁻¹ BMP2 or its vehicle for different incubation times (nsp, non-specific protein). *P<0.01 for BMP2 versus control; +P<0.01 for SOST versus vehicle treatment.