Fig. 5.

Axl-expressing osteoclast precursor cells promote osteoclastogenesis. a Axl was genetically inactivated by shRNA in murine osteoclast progenitor cell line (Raw264.7), and two knockdown clones (shAXL#1 and shAXL#2) were selected by qPCR for further studies. shSCM and shAXL osteoclast progenitor cells were seeded in the transwell migration or invasion chambers. After 24 h, the number of migrated b Or invaded c Cells were counted. shSCM or shAXL osteoclast progenitor cells (2 × 10⁴ cells/well of a 24-well plate) were treated with 35 ng/ml RANK-L. Five days later, mature and differentiated osteoclasts were fixed and stained for tartrate resistant acid phosphatase (TRAP). d Representative images of TRAP-positive, multinucleated osteoclasts (indicated by the black arrows), 5X magnification. e Total number of TRAP-positive, multinucleated ($\ge$3 nuclei) osteoclasts were quantified. shSCM or shAXL osteoclast progenitor cells (2 × 10⁴ cells/well of a 24-well plate) were seeded on a dentine slice treated with or without 35 ng/ml RANK-L. Five days later, dentine slices were stained with toluidine blue solution to observe resorption pits on a dentine slice. f Representative images of bone slices from shSCM and shAXL cells treated with or without RANK-L, 10X magnification. g Total number of resorbed pits per bone slice were quantified.(*p < 0.05, **p < 0.01, ***p < 0.0001