Cerivastatin prevents tumor necrosis factor-alpha-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) exp ression may contribute to endothelial dysfunction. The aim of the present s tudy was to analyze the effect of cerivastatin, a novel HMG CoA reductase i nhibitor, 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 protei n and decreased eNOS mRNA stabilization. This effect was associated with an increased binding activity of BAEC cytosolic proteins to the 3'-untranslat ed region (3'UTR) of eNOS mRNA. Cerivastatin prevented TNF-alpha -induced d ownregulation of eNOS protein expression in a concentration-dependent manne r (10(-8) to 10(-5) M). Cerivastatin also prevented the binding of the cyto solic proteins to 3'-UTR of eNOS mRNA and was associated with eNOS mRNA sta bilization. The reduced expression of eNOS protein by TNF-a was also preven ted by coincubation with cycloheximide. In addition cycloheximide inhibited the binding activity of the cytosolic proteins to 3'-UTR of eNOS mRNA, sug gesting the inducible character of the mentioned-cytosolic proteins. TNF-cc stimulated the translocation of nuclear factor-kappaB (NF-kappa -B), an ef fect that was not modified by cerivastatin. Furthermore, an inhibitor of NF -KB translocation, pyrrolidine dithiocarbamate failed to modify both the do wnregulation of eNOS expression and the increased binding activity of the c ytosolic proteins to 3'-UTR of eNOS mRNA by TNF-alpha. The effect of ceriva statin on eNOS expression and the binding activity of the cytosolic protein s were reversed by coincubation with L-mevalonate. In conclusion, cerivasta tin stabilized eNOS mRNA and upregulated eNOS expression in the endothelium , and this was associated with a decreased binding activity of cytosolic pr oteins 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. The se findings suggest that cerivastatin may have beneficial effects on the en dothelial dysfunction associated with cardiovascular diseases beyond its ef fect on lowering cholesterol. (C) 2001 Elsevier Science Ireland Ltd. All ri ghts reserved.