Localization of putative stem cells in dental epithelium
and their association witch notch and FGF signaling.
Bmp-2 Bmp-4 Bmp-7 shows expres- sion in dental epithelium
and have role in interaction with surrounding mesenchymal tissues.
Neural stem/progenitor stem cells have been isolated from various tissues, including bone marrow, neural tissue, skin, retina, and dental epithelium (3-8).
It has been shown that NT-4 regulates proliferation and differentiation of dental epithelium, and promotes the production of enamel matrixes (25).
It has been shown that NT-4 could regulate proliferation and differentiation of the dental epithelium and promote production of the enamel matrix (27).
This is evident during the cytodifferentiation stage, in which several NOTCH receptors and some of their ligands show complementary expression patterns: Notch1 expression is limited to the intermediate layer, while Dll1 and Jag2 are expressed in the layer adjacent to the inner dental epithelium (figure 2).
14) In vitro cultures of dental epithelium explants show that local application of FGF stimulates Jag2 expression, while the application of BMP produces the opposite effect.
Expression and function of NOTCH path-way component genes during tooth development Stages of tooth Patterns of expression of NOTCH pathway development in mice components during odontogenesis Expression of Notch1, Notch2 and Notch3 in dental lamina (34) Dental lamina (E11) Jag2 in dental epithelium (14) Jag1 in dental epithelium (36) Delta1 in dental lamina (35) Expression of Notch1, Notch2 and Notch3 in entire dental epithelium (34) Jag2 in internal and external dental epithelium (14) Bud (E12, E13-5,5) Jag1 in dental epithelium and mesenchyme, there is no expression in dental epithelium adjacent to mesenchyme.
Tooth development In utero, ectomesenchyme from the neural crest cells migrates to the site of tooth development and forms a complex signaling network with the dental epithelium from the first branchial arch.
It is not completely understood to what extent Fgf8 regulates the odontogenic potential of the dental epithelium, as Fgf8-/mice lack molars and have developed incisors; it is possible FGF9 rescues the incisor development when FGF8 is not present [Zhang et al.
The Fgf8-Bmp4 interaction is initially activated by Shh and restricts Pax9 to the presumptive dental mesenchyme and Pitx2 to the presumptive dental epithelium [Caton and Tucker, 2009; Nie et al.