Characterization of Dental Epithelial Progenitor Cells Derived from Cervical-loop Epithelium in a Rat Lower Incisor

Abstract

Dental epithelial progenitor cells differentiate into various cell types during development of tooth germs. To study this mechanism, we produced immortalized dental epithelial progenitor cells derived from the cervical-loop epithelium of a rat lower incisor. The expression patterns of cytokeratin 14, nerve growth factor receptor p75, amelogenin, Notch2, and alkaline phosphatase were examined by immunohistochemistry in both lower and higher cell densities. The patterns of each were compared in the dental epithelium of rat lower incisors. The results demonstrated that these cells could produce ameloblast lineage cells, stratum intermedium cells, stellate reticulum, and outer enamel epithelium. Furthermore, fibroblast growth factor 10 stimulated proliferation of dental progenitor cells and subsequently increased the number of cells expressing alkaline phosphatase. These results suggest that fibroblast growth factor 10 plays a role in coupling mitogenesis of the cervical-loop cells and the production of stratum intermedium cells in rat incisors.

Changes of the Unique Odontogenic Properties of Rat Apical Bud Cells under the Developing Apical Complex Microenvironment

“…Occurrence of ALP mRNA detected by RT-PCR indicated the spontaneous mineralization ability of ABCs during culture. These results are in agreement with the previous reports which demonstrate that dental epithelial stem cells reside in the apical bud of mouse lower incisors and these cells produce IEE cells as transitamplifying progenitor cells which differentiate into ameloblasts (Harada et al, 1999;Kawano et al, 2004;Harada et al, 2004). In circumstances where adult stem cells survive and proliferate, they undergo the course during which the asymmetric cell division results in the production of one daughter cell remaining in the stem cell compartment and another undergoing further cell divisions and giving rise to differentiated cells (Harada et al, 1999;Morrison et al, 1997).…”

“…In most mammalian developing molars, cervical loop derived Hertwig's epithelial root sheath (HERS) induces and conducts tooth root and periodontal tissue development after tooth crown formation (Hammarström et al, 1996;Luan, et al, 2006;ZeichnerDavid et al, 2003). In contrast, continuous growth throughout the lifetime can be observed in the murine incisor, rendering it a special tooth type (Smith et al, 1975;Harada et al, 1999;Harada et al, 2002;Kawano et al, 2004;Harada et al, 2004;Ohshima et al, 2005). The explanation for this speciality lies in the fact that the specific epithelial structure, i.e.…”

Stem cells for tooth engineering

“…The rodent incisor is a unique model for studying dental EpSC since, in contrast to human incisors or other vertebrates, this tooth grows throughout life. An EpSC niche, which is located in the apical part of the rodent incisor epithelium (cervical loop area), is responsible for a continuous enamel matrix production (Harada et al, 1999;Kawano et al, 2004;Mitsiadis et al, 1998Mitsiadis et al, , 2007Smith and Warshawsky, 1975). In this highly proliferative area, undifferentiated epithelial cells migrate toward the anterior part of the incisor and give rise to ameloblasts (Fig.…”

Distinct Role of Transforming Growth Factor-Beta 1 and Fibroblast Growth Factors in Human Amelobastoma Epithelial Cell Proliferation

“…It has been reported that the growth rate of dental epithelial progenitor cells derived from rat cervical loop, where enamel epithelium is maintained for the continuous growth of rodent incisors, was increased in the presence of FGF-10 at each dose of 10 to 100 ng/ml after 4 day culture based on formazan dye assay [7] and 10 ng/ml after 48 h culture based on the BrdU incorporation experiment [26]. In the ameloblastoma cell line, FGF-10 stimulated the growth of cells in the presence of FGF-10 at 10 or 100 ng/ml after 3 day culture using the same cell counting kit as that in our experiment [23].…”

“…Among these FGFs, the gene expression of FGF-9 and FGF-10 in dental epithelium is strongly involved in tooth development [3][4][5], and FGF-9 expression in the dental epithelium of mouse incisors regulates ameloblast differentiation [6]. Furthermore, FGF-9 or FGF-10 promotes in Human Amelobastoma Epithelial Cell Proliferation the cell proliferation of the dental epithelial progenitor cells established from rat incisors [7] and the dissociated epithelial cells detected in mouse molars [8]. There are few findings on the effect of these FGFs on dental epithelial cells, however, and no study has reported them in ameloblastoma cells.…”