近日，日本东北大学研究人员最新报告说，他们在动物实验中发明了利用诱导多能干细胞制成釉细胞的技术，成釉细胞可以发育出牙齿最坚硬部分——牙釉质。这一成果已发表在《生物化学杂志》（Journal of Biological Chemistry）网络版上。
日本东北大学教授福本敏等人报告说，他们利用来自实验鼠胚胎的牙源性上皮细胞和京都大学教授山中伸弥培育的诱导多能干细胞进行培养，发现约95%的诱导多能干细胞分化成了成釉细胞。经过确认，这些细胞中含有作为牙釉质成分的成釉蛋白。
牙釉质又名珐琅质，是牙冠表层的白色、坚硬、透明组织，保护着牙齿内部的牙本质和牙髓组织。“制造”牙釉质的成釉细胞在一定年龄后就无法生成，所以牙釉质遭破坏后无法再生，碳酸饮料对牙釉质的腐蚀性较强，及时以正确方式刷牙漱口对保护牙釉质至关重要。（生物谷Bioon.com）
doi:10.1074/jbc.M111.285874 jbc.M111.285874
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Role of epithelial-stem cell interactions during dental cell differentiation
Makiko Arakaki, Masaki Ishikawa, Takashi Nakamura, Tsutomu Iwamoto, Aya Yamada, Emiko Fukumoto, Masahiro Saito, Keishi Otsu, Hidemitsu Harada4, Yoshihiko Yamada and Satoshi Fukumoto
Epithelial-mesenchymal interactions regulate the growth and morphogenesis of ectodermal organs such as teeth. Dental pulp stem cells (DPSCs) are a part of dental mesenchyme, derived from the cranial neural crest, and differentiate into dentin forming odontoblasts. However, the interactions between DPSCs and epithelium have not been clearly elucidated. In this study, we established a mouse dental pulp stem cell line (SP) comprised of enriched side population cells that displayed a multipotent capacity to differentiate into odontogenic, osteogenic, adipogenic, and neurogenic cells. We also analyzed the interactions between SP cells and cells from the rat dental epithelial SF2 line. When cultured with SF2 cells, SP cells differentiated into odontoblasts that expressed dentin sialophosphoprotein. This differentiation was regulated by BMP2 and BMP4, and inhibited by the BMP antagonist Noggin. We also found that mouse iPS cells cultured with mitomycin C-treated SF2-24 cells displayed an epithelial cell-like morphology. Those cells expressed the epithelial cell markers p63 and cytokeratin-14, and the ameloblast markers ameloblastin and enamelin, whereas they did not express the endodermal cell marker Gata6 or mesodermal cell marker brachyury. This is the first report of differentiation of iPS cells into ameloblasts via interactions with dental epithelium. Co-culturing with dental epithelial cells appears to induce stem cell differentiation that favors an odontogenic cell fate, which may be a useful approach for tooth bioengineering strategies.
