Fig. 9

Effects of GPR55 interference and GPR55 modulators on osteoclast syncytia. RAW264.7 cells were interfered using non-targeting (si-NT) or Gpr55-targeting (si-GPR55) siRNAs, and then treated without (w/o) (a) or with 15–30 ng/mL RANKL (b). Osteoclast syncytia formation was determined after 72 h as number of nuclei/cell, under fluorescence microscopy. c, d RAW264.7 cells were treated without (w/o) or with 15–30 ng/mL RANKL, in the absence or presence of the GPR55 putative antagonists/agonist (0.5 µM ML-191, 0.5 µM CBD, 30 µM O1918, 1 µM soybean LPI) (c), or of 150 nM (0.2 µg/mL) peptides (Peptide-P1, P1; the irrelevant peptide with the sequence CGGNGPGLC, Irr_P) (d). Osteoclast syncytium formation was determined after 72 h of RANKL treatment as the number of nuclei/cell, under fluorescence microscopy. Data are means ± SE of three independent experiments. *p < 0.05 (Student’s t-tests). w/o, cells incubated without RANKL; RANKL, RANKL-differentiated cells