Statins differ in their ability to block NF-kappaB activation in human blood monocytes.

OBJECTIVE: The benefits of statin therapy in cardiovascular medicine are ascribed to its lipid-lowering effect as well as its anti-inflammatory properties. Whereas all statins have been shown to reduce cholesterol plasma levels, their effect on inflammatory markers has been inconsistent. Here, we show that statins differ markedly in their effectiveness in preventing activation of NF-kappaB, a transcription factor involved in the activation of immediately early genes during inflammation. METHODS: Six statins (atorvastatin (Atv), cerivastatin (Cer), fluvastatin (Flu), lovastatin (Lov), pravastatin (Pra), simvastatin (Sim)) were tested for their ability to influence the induction of NF-kappaB in human monocytes (Mo) during inflammation. Mo isolated from healthy blood donors were incubated with LPS (10 microg/ml) in the presence and absence of statin (0.001-5 microM). NF-kappaB binding activity (EMSA), degradation and phosphorylation of the inhibitor protein IkappaB-alpha (Western blotting), tissue factor (TF) mRNA (rtPCR), and TF activity (clotting assay) were analyzed. RESULTS: All statins inhibited LPS-induced NF-kappaB binding activity in Mo in a dose-dependent manner. The inhibitory effect was due to reduced phosphorylation and degradation of the NF-kappaB inhibitor protein IkappaB, and was primarily dependent on the absence of mevalonate. Whilst this effect appeared with all statins, there were marked differences in the degree of inhibition between the statins. Cer (45 +/- 9% inhibition, p < 0.05) was 9-fold more effective in reducing NF-kappaB activation than Flu (5 +/- 10% inhibition). The differences in the potency of statins (Cer > Atv > Sim > Pra > Lov > Flu) were also reflected at the transcriptional level and the protein level of NF-kappaB controlled tissue factor expression. CONCLUSIONS: The finding that statins differ in their potency in interfering with the activation of NF-kappaB signaling in human monocytes further supports the hypothesis that some statins inhibit the inflammatory response more than others.

Opposite regulation of tissue factor expression by calcineurin in monocytes and endothelial cells.

Tissue factor (TF), the primary initiator of blood coagulation with structural homology to the cytokine receptor family, has been implicated in various vascular processes including metastasis, angiogenesis, and atherosclerosis. Within the vasculature, monocytes and endothelial cells (EC) can be activated to synthesize TF depending on the induction of NF-kappaB. Despite the undisputed value of cyclosporin A (CsA) as an immunosuppressant, problems have emerged due to induction of vascular changes by a poorly understood mechanism. We demonstrate that CsA has opposite effects on TF gene expression, inhibiting NF-kappaB-mediated TF gene transcription in monocytes but enhancing it in EC. To test whether CsA binding proteins (cyclophilins) can mediate these CsA effects we used a nonimmunosuppressant analog of CsA that binds to cyclophilins but does not inhibit the Ca2+/calmodulin-dependent phosphatase calcineurin (Cn). This drug lacked regulatory function for NF-kappaB and TF expression suggesting that Cn is responsible for the inverse gene regulation. The key function of Cn was supported by experiments demonstrating that other phosphatase inhibitors also either positively or negatively regulated NF-kappaB in monocytes and EC. Calcineurin was demonstrated to regulate NF-kappaB activation at the level of IkappaBalpha degradation, because agonist-induced phosphorylation and subsequent degradation of IkappaBalpha is prevented by Cn inhibitors in monocytes but enhanced in EC. These data identify Cn as an opposite regulator in generating transcriptionally active NF-kappaB, and they confirm the presumption that the ability of Cn to participate in NF-kappaB transactivation is not T cell specific.