RANKL-dependent differentiation of osteoclasts. Quantification of the number of multinucleated osteoclasts and their resorptive activity, generated by H1- and MSC-iPS1–derived osteoclast precursors. Cells from day 21 cultures were seeded at 10⁵ cells/96-mm well on dentine slices in the absence or presence of RANKL as indicated and harvested 14 days later for TRAP staining (A) and resorption analysis (B). The data represent the mean ± SD of 4 to 6 wells. *P < .05.