Human odontogenic epithelial cells derived from epithelial rests of Malassez possess stem cell properties

Epithelial cell rests of Malassez (ERM) are quiescent epithelial remnants of the Hertwig’s epithelial root sheath (HERS) that are involved in the formation of tooth roots. ERM cells are unique epithelial cells that remain in periodontal tissues throughout adult life. They have a functional role in the repair/regeneration of cement or enamel. Here, we isolated odontogenic epithelial cells from ERM in the periodontal ligament, and the cells were spontaneously immortalized. Immortalized odontogenic epithelial (iOdE) cells had the ability to form spheroids and expressed stem cell-related genes. Interestingly, iOdE cells underwent osteogenic differentiation, as demonstrated by the mineralization activity in vitro in mineralization-inducing media and formation of calcification foci in iOdE cells transplanted into immunocompromised mice. These findings suggest that a cell population with features similar to stem cells exists in ERM and that this cell population has a differentiation capacity for producing calcifications in a particular microenvironment. In summary, iOdE cells will provide a convenient cell source for tissue engineering and experimental models to investigate tooth growth, differentiation, and tumorigenesis.

This is the Author's Accepted Manuscript of the following article: Human odontogenic epithelial cells derived from epithelial rests of Malassez possess stem cell properties, Takaaki Tsunematsu, Natsumi Fujiwara, Maki Yoshida, Yukihiro Takayama, Satoko Kujiraoka, Guangying Qi, Masae Kitagawa, Tomoyuki Kondo, Akiko Yamada, Rieko Arakaki, Mutsumi Miyauchi, Ikuko Ogawa, Yoshihiro Abiko, Hiroki Nikawa, Shinya Murakami, Takashi Takata, Naozumi Ishimaru and Yasusei Kudo, Laboratory Investigation 96, 1063-1075 (2016), which has been published in final form at https://doi.org/10.1038/labinvest.2016.85.