3 Induction of osteoprotegerin mRNA during differentiation of monocytes into macrophages

Abstract

To prevent alveolar bone resorption in periodontitis, it is important to understand the changes in expression of various molecules during differentiation of osteoclasts from their precursor cells. Since osteoclasts originate from monocytes and macrophages, we looked at changes in mRNA expression of osteoprotegerin (OPG), receptor activator of NF κ-B ligand (RANKL) and receptor activator of NF κ-B (RANK) during differentiation of the THP-1 cell, a human monocytic leukemia cell line, into macrophages. We demonstrated that OPG, a secretory protein and a competitive inhibitor of RANK binding to RANKL, was induced when THP-1 monocytes differentiated into macrophages. In contrast, expression of RANK or RANKL did not change during the differentiation. The induction of OPG mRNA in macrophages possibly influences the regulation of the differentiation of osteoclasts. This work was supported in part by Grant 07-05 from Osaka Dental University Research Funds.