Pluripotent stem cells developed into regenerated tooth by organ germ method in combination with tooth germ-derived epithelium

The regenerative therapy ultimately aims to develop bioengineered organs that can replace lost or damaged organs following disease, injury or aging. Recently, we showed that the artificial organ germ, which generates a structurally correct tooth, could be reconstituted by in vitro cell manipulation (Nature Methods 4, 227-230, 2007). In this study, we revealed that neural crest-like cells, which were differentiated from pluripotent stem cells such as embryonal carcinoma (EC) cells, could develop the regenerated tooth by organ germ method with tooth germ epithelium. EC cells were stimulated with dimethyl sulfoxide (DMSO) and differentiated cells were isolated by cell sorting as DMSO-EC cells. We found that the expressions of pluripotent stem cell marker genes (Oct3/4 and Nanog) could not be detected in DMSO-EC cells. In contrast, the expressions of neural crest-marker genes (Pax3 and Slug) and of dental mesenchyme-marker genes (Msxl, Pax9 and Lhx7) increased in DMSO-EC cells, compared with those in EC cells. Furthermore, the structurally correct tooth can be generated by combining DMSO-EC cells and tooth germ epithelium, both in vitro and in vivo. Our current results indicated the possibility that pluripotent stem cells are applicable as a candidate of cell sources to develop of a bioengineered organ germ for the organ replacement in the future regenerative therapy.