U0126 induces osteoclast differentiation via the p38-NFATc-1 signaling pathway

Osteoclast differentiation plays an important role in bone metabolic diseases, such as osteoporosis, osteosclerosis and so on. In the study, we found that the ERK inhibitor, U0126, significantly increased the number of multinucleated osteoclasts after inducing differentiation of mouse mononuclear macrophage RAW264.7 cells. The Shh-p38-NFATc-1 signaling pathway has been reported to induce osteoclast differentiation in our previous work, and here U0126 also could increase pp38 and NFATc-1 expression as well as NFATc-1 entrance into the nucleus. Animal experiment demonstrated that U0126 accelerated tooth eruption in newborn mice and promoted alveolar bone resorption by inducing osteoclastogenesis. Furthermore, U0126 can rescue delayed tooth eruption caused by LDE225 (a Shh inhibitor) suppression of the p38 signaling pathway. Cytological experiments also revealed that U0126 could rescue the osteoclastic inhibitory effect of LDE225, but not Doramapimod (a p38 inhibitor). Therefore, we conclude that U0126 promotes osteoclast differentiation via the p38-NFATc-1 signaling pathway and relieves the inhibitory effect of LDE225 on osteoclastogenesis. Our study may provide a scientific foundation for dental treatment strategies to enhance osteoclast function in addressing tooth eruption issues, such as impacted teeth, delayed eruption of permanent teeth, and cranioclavicular dysplasia syndrome (CCD). It will also serve as a method for future research into novel approaches to treating disorders linked to bone metabolism.