RANKL-independent osteoclast differentiation induced by TGFβ and TNF-α cytokines.

BMMs from WT, DAP12-/- and DAP12-/-FcRγ-/- were separated and non-adherent preosteoclasts were cultured with RANKL (A, E, I); or pretreated by 2 ng/ml TGFβ (B, F, J) for 2 days, followed by 30 ng/ml TNF-α treatment (C, G, K) or 25 ng/ml RANKL (D, H, L) for another 2 day. TRACP staining was performed at the end of the experiment, as described. TRACP staining is indicated by dark purple. WT: wild-type mice; DKO: mice lacking both DAP12 and FcRγ. Experiment was repeated three times with representative results shown.