Chapter 5 - Developmental Biology of Bone

Abstract

Recent advances in developmental biology, skeletal cell biology, and molecular genetics have increased the understanding of bone development significantly. The development of the vertebrate skeleton depends on the regulated differentiation, function, and interactions of its cellular components. Current understanding of the molecular pathways that control patterning, growth, and differentiation of the various skeletal elements has been derived from a combination of genetics, experimental developmental biology, and in vitro cellular and biochemical studies. Knowledge of embryonic skeletal development provides a better basis for generating strategies to repair cartilage and bone in patients with skeletal diseases such as osteoporosis. Fibroblast growth factors (FGFs) are essential for several aspects of bone development, not only in the ossification of cranial sutures and limb bud outgrowth, but also in growth plate function, that is, longitudinal bone growth. FGFs have been shown to support the proliferation of a variety of mesenchymal and epithelial cells; regulate cell migration, differentiation, and chemotaxis; and be involved in a variety of non-skeletal and skeletal developmental processes. The roles of extracellular matrix proteins, not only as structural components, but also as modulators of signal transduction have come into sharper focus recently. However, much needs to be accomplished in skeletal biology, including a better understanding of endochondral ossification and the function of cartilage in bone remodeling and the factors that control cortical and trabecular bone thickness.