Inhibitory effects of KM91104 on osteoclast differentiation and bone absorption by inhibiting nuclear factor-κB signaling pathway

Abstract

Objective To investigate the effect of KM91104 on osteoclast differentiation and bone absorption and the mechanism. Methods Bone marrow mononuclear macrophage in vitro was cultured, effects of KM91104 (0-40 μmol/L) on osteoclast progenitor cell proliferation, differentiation of osteoclasts, osteoclast bone absorption and osteoclast specific gene expression were observed, and the molecular mechanism of osteoclast function was investigated by Western bloting. Results After treatment of 0, 1.25, 2.50, 5.00 μmol/L of KM91104, the osteoclast counts were respectively 116.67±9.713, 79.67±16.166, 62.33±21.825, 27.33±13.650 (F=16.268, P=0.001). After treatment of 1.25, 2.50, 5.00 μmol/L of KM91104, the bone absorption regions were significantly reduced with the concentration dependence. After treatment of 0, 1.25, 2.50 μmol/L of KM91104, the relative expression of nuclear factor of activated T cells c1 (NFATc1) gene were respectively 0.767±0.010, 0.509±0.012, 0.425±0.009 (F=1 773.069, P=0.000); the relative expression of tartrate resistant acid phosphatase (TRACP) gene were respectively 0.412±0.008, 0.314±0.010, 0.257±0.009 (F=466.743, P=0.000); the relative expression of cathepsin K (CtsK) gene were respectively 0.875±0.011, 0.756±0.007, 0.553±0.009 (F=1 868.721, P=0.000). After treatment of 0, 1.25, 2.50 μmol/L of KM91104, the protein grayscale of phosphorylated p65 (p-p65)/p65 were respectively 0.419±0.011, 0.213±0.036, 0.133±0.006 (F=273.988, P=0.000); the protein grayscale of phosphorylated inhibitory κB-α (p-IκB-α)/inhibitory κB-α (IκB-α) were respectively 0.846±0.021, 0.512±0.053, 0.388±0.011 (F=293.710, P=0.000). Conclusion KM91104 inhibits the osteoclast differentiation and bone absorption, and can be used to treat osteoporosis. Key words: Osteoporosis; Osteoclast; KM91104; Nuclear factor-κB