Quiescent epithelial cell rests of Malassez can differentiate into ameloblast‐like cells

Abstract

Epithelial cell rests of Malassez (ERM) are quiescent epithelial remnants of Hertwig's epithelial root sheath (HERS) that are involved in the formation of tooth roots. After completion of crown formation, HERS are converted from cervical loop cells, which have the potential to generate enamel for tooth crown formation. Cervical loop cells have the potential to differentiate into ameloblasts. Generally, no new ameloblasts can be generated from HERS, however this study demonstrated that subcultured ERM can differentiate into ameloblast-like cells and generate enamel-like tissues in combination with dental pulp cells at the crown formation stage. Porcine ERM were obtained from periodontal ligament tissue by explant culture and were subcultured with non-serum medium. Thereafter, subcultured ERM were expanded on 3T3-J2 feeder cell layers until the tenth passage. The in vitro mRNA expression pattern of the subcultured ERM after four passages was found to be different from that of enamel organ epithelial cells and oral gingival epithelial cells after the fourth passage using the same expansion technique. When subcultured ERM were combined with subcultured dental pulp cells, ERM expressed cytokeratin14 and amelogenin proteins in vitro. In addition, subcultured ERM combined with primary dental pulp cells seeded onto scaffolds showed enamel-like tissues at 8 weeks post-transplantation. Moreover, positive staining for amelogenin was observed in the enamel-like tissues, indicating the presence of well-developed ameloblasts in the implants. These results suggest that ERM can differentiate into ameloblast-like cells.

Signaling Networks Regulating Tooth Organogenesis and Regeneration, and the Specification of Dental Mesenchymal and Epithelial Cell Lineages

“…Similar stem cells were also characterized in exfoliated deciduous teeth and third molars (Rodriguez-Lozano et al 2011). Epithelial stem cells may reside within the epithelial cell rests of Malassez as these cells can be induced to ameloblastlike cells (Shinmura et al 2008).…”

Natural odontogenesis: cellular and molecular basis

“…Это связано с тем, что, когда зуб прорезывается в полость рта, эмалевый эпителий, окружающий коронку зуба, исчезает, и единствен-ный дентальный эпителий сохраняется в ERM. Хотя клетки ERM были выделены [78,79] и дифференци-рованы в амелобластоподобные клетки [79], пока не ясно, имеют ли они одонтогенный потенциал.…”

Stem Cells in Periodontal Regeneration

“…Studies had proved that the combination of Hertwig's epithelial root sheath/epithelial cell rests of malassez and dental mesenchymal stromal/stem cell populations give rise to better outcomes in periodontal regeneration [45][46][47] . Dental pulp cells in combination with porcine epithelial cell rests of malassez can differentiate into ameloblast like cells and generate enamel like tissues, invivo, as shown by positive amelogenin staining [47] . Co-culture of dental follicle cells and Hertwig's epithelial root sheath cells significantly increase bone/cementum related gene expression [45] .…”