Inhibition of multinuclear osteoclast formation by GRGDS peptide.

(A) c-Fms⁺RANK⁻ cells were cultured in the presence of M-CSF and sRANKL with various concentration of GRGDS peptide or 0.5 mg/mL GRGES peptide for 6 days and stained with TRAP. The number of multinuclear TRAP⁺ cells was scored. (B) Osteoclast precursor cells (× 10³) were cultured in the presence of M-CSF and sRANKL with 0.5 mg/mL (a) GRGDS peptide or (b) GRGES peptide for 6 days and stained with TRAP. Note that all cells were TRAP⁺ in the presence of GRGDS peptide; however, a marked decrease in the cell density and multinuclear cells was observed with GRGDS. The bar indicates 50 μm. (C) c-Fms⁺RANK⁻ cells were cultured in the presence of M-CSF and sRANKL with either 0.5 mg/mL GRGDS peptide, 0.5 mg/mL GRGES peptide, or without peptide for 8 hours, then the number of adherent cells was scored. Note that initial attachment was not affected by GRGDS peptide. (D) A large number of c-Fms⁺RANK⁻ cells (1 × 10⁴) were cultured in the presence of M-CSF and sRANKL with 0.5 mg/mL (a) GRGES peptide or (b) GRGDS peptide for 4 days. The cell fusion was observed even in the presence of GRGDS in this case. The bar indicates 100 μm.