Hydroxyapatite- and Amelogenin Protein-Induced Expression of Mineralization-Related Genes in a Dental Epithelial Cell Line

Liming Xu,Hidemitsu Harada,Toshiyuki Ikoma,Akiyoshi Taniguchi

doi:10.2174/1874070700802010116

Abstract

Hydroxyapatite (HAp), a major inorganic component of hard tissues, has been widely used as a novel scaffold for bone or tooth tissue regeneration. However, the effects of HAp on dental cells at the molecular level are poorly understood. In the present study, we evaluated the effects of HAp on differentiation- and mineralization-related gene expression in the dental epithelial cell line (HAT-7). HAT-7 cells were observed to spread on the surface of HAp sintered disks and to increase the expression of several differentiation- and mineralization-related genes. Furthermore, amelogenin and HAp synergistically induced differentiation resulting in increased amelogenin mRNA expression in HAT-7 cells. The results from this study provide important information to develop novel biomaterials for enamel regeneration.

Highlights

Amelogenin is a major component of enamel matrix proteins, accounting for more than 90% of enamel matrix proteins [1]
The attachment of the cells cultured on the surface of HAp sintered disk did not differ from that of cells cultured on the tissue culture polystyrene (TCP) plate
The morphology of human ameloblast lineage cells is altered by increased calcium in the media, and differentiating ameloblast-lineage cells can be maintained in a functional state by culturing in the presence of 0.05 mM calcium [29, 30]

Summary

Introduction

Amelogenin is a major component of enamel matrix proteins, accounting for more than 90% of enamel matrix proteins [1]. We have previously reported that amelogenins induce differentiation of the dental epithelial cell line (HAT-7) and in an autocrine manner increase levels of amelogenin mRNA by enhancing its stability [2, 3]. Through this unique auto-regulatory mechanism amelogenins are produced in large quantities by ameloblasts and accelerate enamel formation. Ameloblastin, is another enamel matrix protein that comprises 5-10% of enamel matrix proteins [1]. The data suggest that HAp-coated implants may be able to maintain optimal osseointegration over time, though the molecular mechanisms by which HAp affects dental cell differentiation and mineralization are poorly understood [23]

Methods

Results

Conclusion