Effect of WEAO on the gene expression of transcription factors involved in osteoclast differentiation. (A, B) BMMs were cultured with vehicle (distilled water) or WEAO (80 μg/mL) in the presence of M-CSF (60 ng/mL). Total RNA and cell lysates were obtained following stimulation with RANKL (100 ng/mL) for the indicated times. (A) Relative mRNA expression levels of NFATc1, c-Fos, Id2, and MafB were determined by qPCR. **p < 0.01 versus vehicle-treated control. (B) Total cell lysates were subjected to Western blot analysis with antibodies against NFATc1, c-Fos, and p38. p38 was used as a loading control. (C) BMMs transduced with retroviruses expressing either pMX-IRES-GFP (pMX) or pMX-CA-NFATc1-IRES-GFP (pMX-CA-NFATc1) were cultured with vehicle or WEAO (80 μg/mL) in the presence of M-CSF (60 ng/mL) and RANKL (100 ng/ml) for 4 days. The number of osteoclasts (Oc) was counted. **p < 0.01.