The prevention of titanium-particle-induced osteolysis by OA-14 through the suppression of the p38 signaling pathway and inhibition of osteoclastogenesis.

Wear-particle-induced osteolysis leads to prosthesis loosening, which is one of the most common causes of joint-implant failure, a problem that must be fixed using revision surgery. Thus, a potential treatment for prosthetic loosening is focused on inhibiting osteoclastic bone resorption, which prevents wear-particle-induced osteolysis. In this study, we synthesized a compound named OA-14 (N-(3- (dodecylcarbamoyl)phenyl)-1H-indole-2-carboxamide) and examined how OA-14 affects titanium (Ti)-particle-induced osteolysis and osteoclastogenesis. We report that OA-14 treatment protected against Ti-particle-induced osteolysis in a mouse calvarial model. Interestingly, the number of tartrate-resistant acid phosphatase-positive osteoclasts decreased after treatment with OA-14 in vivo, which suggested that OA-14 inhibits osteoclast formation. To test this hypothesis, we conducted in vitro studies, and our results revealed that OA-14 markedly diminished osteoclast differentiation and osteoclast-specific gene expression in a dose- and time-dependent manner. Moreover, OA-14 suppressed osteoclastic bone resorption and F-actin ring formation. Furthermore, we determined that OA-14 inhibited osteoclastogenesis by specifically blocking the p38-Mitf-c-fos-NFATc1 signaling cascade induced by RANKL (ligand of receptor activator of nuclear factor κB). Collectively, our results suggest that the compound OA-14 can be safely used for treating particle-induced peri-implant osteolysis and other diseases caused by excessive osteoclast formation and function.