Exogenous regucalcin suppresses osteoblastogenesis and stimulates adipogenesis in mouse bone marrow culture.

Regucalcin plays a pivotal role in regulating intracellular calcium homeostasis and consequently has a profound effect on multiple intracellular signal transduction pathways. The regucalcin transgenic rat displays pronounced bone loss and hyperlipidemia. Consistent with these effects exogenous regucalcin has been shown to promote osteoclastogenesis in mouse bone marrow cultures and to suppress the differentiation and mineralization of MC3T3 osteoblast precursors. Regucalcin may induce hyperlipidemia in vivo by suppressing osteoblast differentiation and stimulating adipogenesis in bone marrow mesenchymal stem cells. The present study demonstrates that exogenous regucalcin suppresses differentiation to osteoblasts and stimulates adipogenesis in mouse bone marrow cell culture ex vivo. Moreover, exogenous regucalcin was found to enhance adipogenesis stimulated by insulin which is involved in the extracellular signal-related kinase pathway in 3T3-L1 adipocytes in vitro.