Module 8: Figure bone cell differentiation
Control of bone cell differentiation.
Differentiation of osteoclasts from haematopoietic stem cells (HSCs) occurs through a series of steps (osteoclastogenesis) controlled by colony-stimulating factor-1 (CSF-1) and receptor activator of nuclear factor κB (NF-κB) ligand (RANKL), which is located on the surface of the osteoblasts. Differentiation of the osteoblasts from mesenchymal stem cells (MSCs) occurs through a series of steps controlled by the Wnt signalling pathway. The osteoclasts release sclerostin (SOST), which inhibits the Wnt signalling to reduce osteoblastogenesis. As the osteoblasts secrete bone (white arrows), they gradually become buried in the mineralized matrix where they are transformed into star-shaped osteocytes.