Inhibitory effect of pitavastatin (NK-104) on the C-reactive-protein-induced interleukin-8 production in human aortic endothelial cells

Recent data have indicated that CRP (C-reactive protein) plays a role in atherosclerosis, in addition to being a marker for inflammatory diseases. IL-8 (interleukin-8), a CXC chemokine, is present in human coronary atheroma and promotes monocyte-endothelial cell adhesion. In the present study, we examined the effect of pitavastatin (NK-104), a synthetic statin (3-hydroxy-3-methylglutaryl CoA reductase inhibitor), on IL-8 production induced by CRP in human AoEC (aortic endothelial cells). We also investigated whether CRP can induce IL-8 production and if the activation of signalling pathways are functionally related. The concentrations of IL-8 in the media after stimulation with CRP were measured by ELISA, and the expression of IL-8 mRNA was assessed by Northern blot. The phosphorylation of MAPKs (mitogen-activated protein kinases) was determined by Western blot. The production of IL-8 induced by CRP (10 mu g/ml) was enhanced significantly and was inhibited by pitavastatin. The expression of IL-8 mRNA was increased in a dose-dependent manner after stimulation with CRP (1-100 mu g/ml), whereas expression of IL-8 mRNA induced by CRP (50 mu g/ml) was significantly diminished by 5 mu M pitavastatin. Furthermore, specific MAPK inhibitors (PD98059, SB203580 and SP600125) inhibited the expression of IL-8 mRNA induced by CRP (50 mu g/ml). The phosphorylation of all three MAPKs [ERK (extracellular-signal-regulated kinase), p38 MAPK and JNK (c-jun N-terminal kinase)] induced by CRP (10 mu g/ml) was also significantly inhibited by pitavastatin. Our results suggest that CRP may play a role in atherosclerosis via IL-8 production and pitavastatin may prevent the progression of atherosclerosis not only by lowering plasma low-density lipoprotein cholesterol levels, but also by suppressing IL-8 production in endothelial cells through the inhibition of MAPK (ERK, p38 MAPK and JNK) pathways.