Abstract: Objective  To explorethe cellular differentiation mechanisms, with  Cathepsin K (Ctsk)-positive skeletal stem cells (SSCs) lineage tracing, underlying alveolar bone tissue, periodontal ligament, and dentin development, as well as the regulatory role of peripheral nerves.Methods  Ctsk-Cre;tdTomato;Col2.3-GFP  dual-fluorescence mouse models were generated. Tissues including alveolar bone, periodontal ligament, and dental pulp were harvested from neonatal mice for Ctsk-positive lineage tracing and immunofluorescence staining. Futhermore, an inferior alveolar nerve transection model was established to analyze tdTomato⁺Col2.3-GFP⁺ double-positive cells.Results  The Ctsk-Cre;tdTomato;Col2.3-GFP fluorescent reporter mouse model was successfully generated. Lineage tracing and immunofluorescence staining in neonatal mice revealed that tdTomato+ cells in the alveolar bone expressed osterix, tdTomato+ cells in the periodontal ligament expressed Periostin, and tdTomato+ cells in the dentin expressed Col2.3-GFP.  Further analysis with the inferior alveolar nerve transection model showed reduced tdTomato+ lineage and decreased numbers of differentiating tdTomato⁺ Col2.3-GFP⁺ double-positive cells in denervated mice compared to the nerve-intact group.Conclusions  During the developmental stage of alveolar bone in neonatal mice, Ctsk positive cells participated in the development of bone tissue, periodontal ligament, and dentin, which were regulated by the inferior alveolar nerve. It shed light on injury repair and homeostasis of adulthood skeleton.

Key words: lineage tracing, genetic mouse model, fluorescence, development, nerve, dentin