Immunomodulation and Reparative Dentinogenesis by the Wnt Agonist Peptide L803-Mts In Vitro and In Vivo

Materials used for conventional vital pulp therapy (VPT) promote dentine barrier formation but do not harness the intrinsic regenerative potential of the dental pulp. This study tested the hypothesis that L803-mts, a glycogen synthase kinase (GSK)-3β inhibitory peptide, (i) enhances odontogenic differentiation of dental pulp stem cells (DPSCs) and modulates macrophage pro-inflammatory responses under inflammatory conditions in vitro; and (ii) promotes reparative dentinogenesis in vivo at levels comparable to mineral trioxide aggregate (MTA).

DPSC monocultures and DPSC-macrophage co-cultures were treated with L803-mts under inflammatory conditions (1 μg/mL lipopolysaccharide). Odontogenic differentiation was assessed by alkaline phosphatase activity, gene expression, alizarin red staining, and Western blotting. Macrophage polarization was evaluated by flow cytometry and enzyme linked immunosorbent assay. Reparative dentinogenesis was assessed in vivo in a rat pulp injury model using micro-computed tomography, histology, and immunofluorescence. Statistical significance was set at p < 0.05.

L803-mts significantly enhanced mineralisation and significantly upregulated dentinogenic markers (Dentine Matrix Acidic Phosphoprotein 1 and Dentine sialophosphoprotein) under inflammatory conditions. In DPSC-macrophage co-cultures, L803-mts significantly reduced pro-inflammatory cytokines and polarized macrophages to the anti-inflammatory phenotype (p < 0.05). In vivo, L803-mts achieved mineral density comparable to MTA (1.17 vs. 1.32 gHA/cm³; p > 0.05), with lower mineral volume (0.03 vs. 0.06 mm³; p < 0.05).

L803-mts promoted reparative dentinogenesis through Wnt signalling activation and immunomodulation, supporting its potential as a biologically driven candidate for VPT.