Figure 2

Actin ring formation and bone resorption are enhanced by TG2 knockdown. (a,b) BMMs were transfected with control or TG2 siRNA and cultured with M-CSF (30 ng/ml) and RANKL (100 ng/ml) for three days. Cells were stained with rhodamine-phalloidin conjugate and DAPI to visualize F-actin and nuclei, respectively. The number of actin rings was counted, and the sealing zone (SZ) area per osteoclast was measured. **P < 0.005 versus control siRNA. Scale bar, 100 μm. (c) After transfection with control or TG2 siRNA, BMMs were incubated with M-CSF (30 ng/ml) and RANKL (100 ng/ml) for the indicated number of days. The mRNA levels of DC-STAMP, TRAP and ATP6v0d2 were measured by real-time PCR. (d,e) BMMs were transfected with control or TG2 siRNA, and a dentine resorption assay was performed. Black areas indicate resorbed lacunae on the dentin slices. The total resorption area, resorption area per osteoclast, and depth per pit were calculated from four randomly selected images. CTL, control. *P < 0.05; **P < 0.005 between indicated groups. Scale bar, 100 μm.