Recombinant LD78 protein, a member of the small cytokine family, enhances osteoclast differentiation in rat bone marrow culture system.

Cytokine LD78 is a member of the small inducible protein family involved in cell growth, wound healing and inflammation. However, its exact function is not known. In this study, we demonstrated that recombinant LD78 alpha and its variant LD78 beta proteins stimulate osteoclast-like cell formation in rat bone marrow cultures in the presence of 1 alpha, 25-dihydroxyvitamin D3. This enhancing activity was independent of prostaglandin synthesis. This is the first report which describes the effect of proteins involved in the small inducible protein family on the differentiation of osteoclasts.