Human periodontal ligament cells derived from deciduous teeth induce osteoclastogenesis in vitro

The receptor activator of NF-kappa B gerin (OPG), are the important proteins involved the expressions of RANKL and OPG in cultured ligand (RANKL) and its decoy receptor, osteoprotegerin osteoclastogenesis. In this study, we investigated human periodontal ligament cells derived from deciduous teeth (DPDL cells) and their roles in osteoclastogenesis. Northern blotting revealed that the OPG mRNA was down-regulated by application of 10(-8)M 1 alpha, 25(OH)2 vitamin D-3 [1,25-(OH)(2)D-3] and 10(-7) M dexamethasone (Dex). In contrast, RANKL mRNA was up-regulated by the same treatment. Western blotting demonstrated a decrease in OPG following application of 1, 25-(OH)2D3 and Dex. Tartrate-resistant acid phosphatase (TRAP)-positive multinuclear cells (MNCs) were induced when DPDL cells were co-cultured with mouse bone marrow cells in the presence of 1,25-(OH)2D3 and Dex. TRAP-positive MNCs increased significantly when the DPDL cells were co-cultured with bone marrow cells in the presence of anti-human OPG antibody together with 1, 25-(OH)2D3 and Dex. These results indicate that PDL cells derived from deciduous teeth synthesize both RANKL and OPG and could regulate the differentiation of osteoclasts. (C) 2002 Elsevier Science Ltd. All rights reserved.