ABSTRACT
The aim of the present study was to determine the effects of the Ca2+/calmodulindependent protein kinase pathway inhibitor KN93 on osteoclastogenesis. RAW264.7 cells were incubated with macrophage colonystimulating factor (MCSF) + receptor activator of nuclear factor kappalightchainenhancer of activated B cells ligand (RANKL) to stimulate osteoclastogenesis and then treated with 10 µM KN93. The methods included tartrateresistant acid phosphatase (TRAP) staining, bone resorption activity assays, filamentous (F)actin staining, determination of intracellular calcium ([Ca2+]i) levels, monitoring of osteoclastspecific gene expression levels and measurement of key transcription factors protein levels. The results suggested that KN93 inhibited the formation of TRAPpositive multinucleated cells, shaping of Factin rings and resorption activity of the cells. In addition, KN93 decreased the concentration of [Ca2+]i, expression levels of osteoclast specific genes and protein levels of critical transcription factors in the MCSF + RANKLinduced osteoclast model. In summary, KN93 may directly affect the differentiation and activation of osteoclasts, potentially through the Ca2+/calmodulindependent protein kinase signaling pathway.
