C-Reactive Protein Activates the Nuclear Factor-Kappab Pathway and Induces Vascular Cell Adhesion Molecule-1 Expression through Cd32 in Human Umbilical Vein Endothelial Cells and Aortic Endothelial Cells

C-reactive protein (CRP) contributes to the process of atherosclerosis by inducing pro-inflammatory changes in endothelial cells. However, the exact receptor involved in CRP-induced endothelial changes remains unclear . Human umbilical vein endothelial cells (HUVECs) and human aortic endothelial cells (HAECs) were used for the experiments. After incubation with CRP, immunoblotting showed a significant decrease of IkappaB protein and electrophoretic mobility shift assay showed a significant increase of nuclear NF-kappaB binding capacity. These changes were associated with a significant increase of vascular cell adhesion molecule-1 (VCAM-1) expression. The mRNA level of CD32, the major binding protein for CRP in endothelial cells , increased significantly as measured by Northern blot and Western blot. When these cells were transfected with siRNA directed against CD32, the mRNA of CD32 decreased significantly. The IkappaB degradation, NF-kappaB nuclear translocation and VCAM-1 up-regulation induced by CRP were all inhibited by treatment with siRNA against CD32. SB 203580 , a P38 inhibitor, significantly attenuated the CRP-induced responses while SP600125 (c-jun kinase inhibitor) did not. In conclusion, CRP-induced IkappaB degradation, NF-kappaB nuclear translocation and VCAM- 1 protein expression in HUVECs and HAECs. CRP also increased the expression of CD32, which might serve as the receptor for CRP in endothelial cells and mediated the effects of CRP