Identification of GLDN⁺ odontogenic stem cells as crucial for human tooth development and regeneration

The dental papilla (DP) is essential for the development of dentin and pulp. The extensive cellular heterogeneity within the DP is a critical factor underlying the complex and precise formation of dental structures during odontogenesis. However, the critical cell types within human DP that play essential role in tooth development and regeneration remain largely uncharacterized. In this study, we analyzed the heterogeneity of human DP cells using single-cell sequencing and identified Gliomedin (GLDN)⁺ DP stem cells (DPSCs) were a group of progenitors at an early stage of tooth development and play a key role in the development of pulp and dentin. GLDN⁺ DPSCs strategically accumulate in human DP tissue near the interface of the newly formed dentin or pulp. Functional assays demonstrated that GLDN⁺ DPSCs exhibited enhanced self-renewal, migratory capacity, and odontogenic differentiation potential in vitro compared to GLDN^- DPSCs. Moreover, GLDN⁺ DPSCs effectively induce the migration and tube formation of endothelial cells, which are essential for tooth development. The ectopic dental pulp regeneration model confirmed that GLDN⁺ DPSCs can regenerate a vascularized dental pulp structure with an odontoblast layer in vivo. Given their functional capabilities, this population of cells has been designated as GLDN⁺ odontogenic stem cells (OSCs). Mechanistically, GLDN is essential for maintaining the phenotype and function of GLDN⁺ OSCs through BMP5 signaling via autocrine and paracrine mechanisms. In conclusion, this study identifies a previously uncharacterized essential subpopulation of OSCs essential for dental pulp development and regeneration.