2004 Volume 67 Issue 1 Pages 103-110
Receptor activator of NF-κB ligand (RANKL) is necessary for osteoclast formation. 1,25-dihydroxyvitamin D_3 (1,25-(OH)_2D_3) induces RANKL expression in osteoblast cells. It has been reported that protein kinase C (PKC) mediates RANKL expression induced by PMA. However, details of the role of PKC isozymes in RANKL expression are not clear. In order to clarify the involvement of PKC isozymes, we investigated the effect of various PKC inhibitors on RANKL expression induced by 1,25-(OH)_2D_3 in the bone marrow derived stromal cell line ST 2. Rottlerin, which inhibits PKC-δ specifically, was used to determine the function of PKC-δ on RANKL expression. Although rottlerin decreased 1,25-(OH)_2D_3 induced RANKL expression in ST 2, staurosporine, which is a nonspecific PKC inhibitor, did not decrease the expression. These results indicate that PKC-δ may be involved in 1,25-(OH)_2D_3-induced RANKL expression.
