The effect of FcγR on CRP-induced RANKL expression in monocytes. (A) Peripheral blood CD14+ monocytes were pretreated with anti-CD64 (FcγRI inhibitor), anti-CD32 (FcγRIIa inhibitor), or anti-CD16 (FcγRIIb inhibitor) for 1 h and were cultured with 1 μg/mL of CRP for 72 h. The expression of RANKL mRNA was determined using real-time PCR. The expression of RANKL mRNA decreased after inhibition of FcγRI, FcγRIIa, and FcγRIIb. (B) After peripheral blood CD14+ monocytes were cultured with 1 μg/mL of CRP for 72 h, the gene expressions of FcγRI, FcγRIIa, and FcγRIIb were determined using real-time PCR. The expressions of FcγRI, FcγRIIa and FcγRIIb mRNA were increased by CRP stimulation. (C) CRP-induced expression of intracellular signal molecules was determined by Western blotting. The amount of protein expression was normalized to beta-actin, and the ratio of the phosphorylated form to the total form was calculated. CRP increased the phosphorylation of Syk, Akt, ERK and JNK. The data represents the mean ± SEM for three independent experiments; *
P <0.05 and **
P <0.01. CRP, C-reactive protein; FcγR, Fcgamma receptors; RANKL, receptor activator of nuclear factor kappa-B ligand; SEM, standard error of the mean; TNF, tumor necrosis factor.