Role Of Fibroblast Growth Factor 18 In Regulating The Differentiation Of Odontoblast Cells And Its Signal Pathway

Odontoblast is a special type of highly differentiated, tall columnar cell residing in pulp-dentin complex. As it is the only cell that secrete dentin matrix protein, it is in charge of dentin formation during tooth development and post-trauma repairation in postnatal tooth. So it is important to clarify the mechanism of odontoblast differentiation and mineralization, which is governed by a great deal of sequential and reciprocal interactions between epithelial and mesenchymal tissues.Fibroblast Growth Factor 18(FGF18) is a newly discovered member of FGFs family. Sequence comparison indicates that FGF18 is highly conserved between humans and mice and is most homologous to FGF8 and FGF17 among the FGF family members. It is a unique secreted signaling molecule in several adult and developing tissues and plays a crucial role in development of some ectodermal organs like midbrain. It is also a pleiotropic growth factor that stimulates proliferation in some tissues such as articular cartilage and bone through MAPK signal pathway. In FGF18 knock-out mouse, ossification of long bone and craniofacial bone was delayed, which indicated that FGF18 is a regulatory factor of osteoblast differentiation. It is interesting that FGF18 is expressed in a distinct temporal and spatial pattern during mouse odontogenesis and its expression is upregulated with the differentiation of odontoblasts, which suggests that there is great possibility of FGF18 to participate in the proliferation and differentiation of ondontoblast. Thus, the aim of this study was to investigate the role of FGF18 in regulating the proliferation and differentiation of odontoblast cells and its signal pathway. The present study consists of three parts as follow:...