[Progress in the treatment targeting intracellular signaling in the context of osteoimmunology].

The appropriate intracellular signaling pathways are activated via binding of receptors on the cell surface to ligands such as cytokines and cell surface antigens. The tyrosine kinase transduce the first "outside to in" signals to be phosphorylated following receptor binding to its ligand. Among them, members of Janus kinase (Jak) family and Spleen tyrosine kinase (Syk) family are essential for the signaling pathways of various cytokines and are implicated in the pathogenesis of autoimmune inflammatory disease. The development of low molecular weight kinase inhibitors targeting Jak and Syk appears to be successful for the treatment of rheumatoid arthritis, a representative inflammatory disease. These inhibitors also succeed to regulate joint destruction. On the other hand, calcineurin inhibitors such as tacrolimus and vitamin D are also effective for immune regulation as well as bone metabolism through the inhibition of nuclear factors. Taken together, regulation of cellular signals functioning on immunity as well as bone metabolism may have a potential to approach to the treatment of osteo-immune diseases.