Cerivastatin prevents tumor necrosis factor-α-induced downregulation of endothelial nitric oxide synthase:: role of endothelial cytosolic proteins

Cardiovascular disease is accompanied by an impaired endothelium-dependent vasodilatory response. Loss of endothelial nitric oxide synthase (eNOS) expression may contribute to endothelial dysfunction. The aim of the present study was to analyze the effect of cerivastatin, a novel HMG CoA reductase inhibitor, on tumor necrosis factor-alpha (TNF-alpha)-induced downregulation of eNOS protein expression in bovine aortic endothelial cells (BAEC). TNF-alpha (10 ng/ml)- incubated BAEC showed a reduced expression of eNOS protein and decreased eNOS mRNA stabilization. This effect was associated with an increased binding activity of BAEC cytosolic proteins to the 3'-untranslated region (3'UTR) of eNOS mRNA. Cerivastatin prevented TNF-alpha -induced downregulation of eNOS protein expression in a concentration-dependent manner (10(-8) to 10(-5) M). Cerivastatin also prevented the binding of the cytosolic proteins to 3'-UTR of eNOS mRNA and was associated with eNOS mRNA stabilization. The reduced expression of eNOS protein by TNF-a was also prevented by coincubation with cycloheximide. In addition cycloheximide inhibited the binding activity of the cytosolic proteins to 3'-UTR of eNOS mRNA, suggesting the inducible character of the mentioned-cytosolic proteins. TNF-cc stimulated the translocation of nuclear factor-kappaB (NF-kappa -B), an effect that was not modified by cerivastatin. Furthermore, an inhibitor of NF-KB translocation, pyrrolidine dithiocarbamate failed to modify both the downregulation of eNOS expression and the increased binding activity of the cytosolic proteins to 3'-UTR of eNOS mRNA by TNF-alpha. The effect of cerivastatin on eNOS expression and the binding activity of the cytosolic proteins were reversed by coincubation with L-mevalonate. In conclusion, cerivastatin stabilized eNOS mRNA and upregulated eNOS expression in the endothelium, and this was associated with a decreased binding activity of cytosolic proteins to 3'-UTR of eNOS mRNA. The effect of cerivastatin on the regulation of eNOS expression was independent of NF-kappaB mobilization by TNF-a. These findings suggest that cerivastatin may have beneficial effects on the endothelial dysfunction associated with cardiovascular diseases beyond its effect on lowering cholesterol. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.