C/EBPα overexpression mediates OC differentiation and strongly induces gene expression with RANKL-evoked lineage commitment.
A, MBM cells expressing the GFP control (GFP) or FLAG-C/EBPα were treated with M-CSF alone (10 ng/ml) for 4 days and then submitted to Western blotting analysis using β-actin as a loading control. A, endogenous C/EBPα; B, FLAG-C/EBPα. B, MBM cells expressing GFP or FLAG-C/EBPα (C/EBPα) were cultured with M-CSF (10 ng/ml) plus RANKL (1 ng/ml) or M-CSF (10 ng/ml) plus RANKL (10 ng/ml) for 4 days. The cultures were then stained for TRAP activity. Scale bars = 200 μm. C, quantification of B for the number of TRAP-positive multinucleated cells in at least three independent experiments. D and E, quantification of OC size for B via the number of nuclei (D) and size (E) of TRAP-positive multinucleated cells in at least three independent experiments. F, MBM cells expressing GFP or C/EBPα were stimulated with M-CSF (10 ng/ml) plus RANKL (1 ng/ml) for 3 days. Gene expression was assessed by qPCR using Hprt as a loading control from three independent experiments. The numbers in parentheses show concentration in nanograms per milliliter. Error bars show averages ± S.D. *, p < 0.05; NS, not significant.