Chapter 51 - Fibroblast Growth Factor (FGF) and FGF Receptor Families in Bone

Abstract

Multiple experimental and genetic evidence indicates that fibroblast growth factors (FGFs) and FGF receptors (FGFRs) play important roles in the control of endochondral and intramembranous bone formation. Several FGF members are expressed during early stages of development in mammals, and their expression is related to skeletal development. During intramembranous bone formation, FGF-2 transcripts are found in mesenchymal cells and osteoblasts. During skeletal development, FGF-1 is expressed in proliferating and hypertrophic chondrocytes; FGF2 is present in resting and proliferating chondrocytes whereas FGF17 and 19 are widely expressed. FGFs 2, 7, 18 and 22 are expressed in postnatal growth plate. In the developing bone, FGF-2, -9, -18, and -20 are expressed in the calvaria and limbs. FGF-2 is produced by and stored in the extracellular matrix. During skeletal tissue development, FGF's actions are dependent on the expression and interactions with FGFRs. However, the cellular and molecular effects of FGF and FGFRs in bone cells are not fully understood. Identification of the signal transduction pathways that are activated by FGF/FGFR interactions and that lead to the expression of specific genes in skeletal cells may help to better understand the regulatory effects of FGFs during osteogenesis in vivo, and may allow for the development of therapeutic approaches to stimulate bone formation and to improve bone regeneration.