Amelogenin Promotes Periodontal Bone Regeneration by Inducing Bone Marrow Mesenchymal Stem Cell Homing

Abstract

Amelogenin has been widely used in clinical practice for periodontal bone regeneration. However, the precise mechanism underlying its osteogenic effects remains incompletely understood. In this study, we hypothesized that amelogenin enhances periodontal bone regeneration by facilitating the migration and homing of bone marrow mesenchymal stem cells (BMMSCs). BMMSCs were used to evaluate the cell migration promoting ability of amelogenin by the Transwell test. Immunofluorescence was performed to assess the beta-catenin nuclear translocation following amelogenin treatment. To investigate amelogenin-induced cell homing in vivo, we established a green fluorescent protein (GFP)-labeled bone marrow transplantation model using BALB/c mice transgenic for GFP. The migratory effects of amelogenin were examined in this model, with Wnt3a, a Wnt/β-catenin pathway activator, serving as a positive control. Subsequently, cell homing and bone regeneration were evaluated through a fluorescence microscope, micro-CT, hematoxylin and eosin (H&E), and Masson staining. In vitro Transwell assays demonstrated that amelogenin significantly enhanced BMMSC migration, with effects comparable with Wnt3a, a canonical Wnt/β-catenin pathway activator. Immunofluorescence analysis revealed pronounced nuclear translocation of β-catenin in BMMSCs following a 24-h amelogenin treatment. Notably, these effects were abolished by a Wnt/β-catenin pathway inhibitor, confirming the pathway’s involvement. In GFP-labeled bone marrow-transplanted mice, amelogenin treatment significantly increased GFP⁺ cell recruitment to the bone defect site, mirroring the effects of Wnt3a. Micro-CT and histological (H&E) analyses further demonstrated that both amelogenin and Wnt3a accelerated bone regeneration compared with untreated controls. Crucially, this regenerative effect was suppressed upon Wnt/β-catenin pathway inhibition, reinforcing the mechanistic link between amelogenin and β-catenin-mediated osteogenesis. Amelogenin and Wnt3a promoted periodontal bone regeneration both in vitro and in vivo by enhancing BMMSC migration through Wnt/β-catenin signaling activation.