FIGURE 9.
CXCR4 deficiency inhibits cell proliferation and osteoblast differentiation induced by BMP. Primary osteoblastic cells were derived from newborn (days 1–3 after birth) calvariae of Osx::CXCR4fl/fl (KO) mice and Cre-null littermate controls (WT). A, BrdU incorporation for 6 h in WT or KO calvaria cells. B, qPCR measurements of base-line mRNA levels of Alp and Ocn relative to Gapdh control in calvaria cells of WT or KO mice. C–F, calvaria cells were stimulated with rhBMP2 (C and D) or rhBMP6 (E and F) protein at 100 ng/ml for 4 or 7 days or were maintained in culture medium without any stimulation as controls. ALP activities were measured in cell lysates and normalized to the level of total cellular protein. OCN levels were measured in cell medium using ELISA. Cultures were pooled from calvariae of n = 3 WT or KO mice, and triplicate wells of cells were used for each sample. Experiments were repeated twice using mice from two different litters. Measurements are expressed as mean ± S.D. *, p < 0.05 versus respective medium-only control.