Figure 3.

Osteoclast formation is regulated through the activation of mitogen-activated protein kinases (MAPKs) and their downstream molecules. (A) Crucial molecules involved in osteoclastogenesis, such as osteoprotegerin (OPG), receptor activator of nuclear factor-κB ligand (RANKL), and RANK, in RAW 264.7 cells cultured with RANKL were time-dependently assessed after melittin treatment (1 µg/ml). (B) At the downstream of the RANKL-RANK system, the expression of TNF receptor-associated factor-6 (TRAF6) and MAPKs in culture medium-treated cells and melittintreated cells was measured. (C) Phosphorylation of c-Jun, c-Fos and nuclear factor of activated T cells cytoplasmic 1 (NFATc1) in RAW 264.7 cells cultured with RANKL was assessed according to treatment with and without melittin by western blot analysis. Data are representative of 3 independent experiments.