Wnt-dependent ontogeny of acellular cementum-forming cementoblasts on the tooth root surface

Cementum is a specialized mineralized tissue that covers the tooth root surface and anchors the tooth to the surrounding periodontal ligament. The cervical acellular cementum (AC) is indispensable for periodontal attachment and represents a key target for periodontal regenerative therapies. However, the developmental origin and molecular identity of AC-forming cementoblasts remain poorly understood. Here, through an integrated spatial and single-cell transcriptomic analysis, we identify AC-forming cementoblasts as a distinct population of noncanonical mineralizing cells enriched for cell-matrix organization and Wnt signaling signatures, distinguishing them from cellular cementum-forming cementoblasts localized in the apical portion. Lineage tracing using a Wnt inhibitory factor 1 (Wif1-creER) demonstrates that AC-forming cementoblasts originate exclusively from peri-epithelial apical Wif1⁺ cells of the elongating tooth root via canonical Wnt signaling activation. Collectively, our findings uncover the unique ontogeny and molecular signature of acellular cementum, providing insights into the formation and maintenance of the periodontal attachment apparatus.