geranylgeranyl-pyrophosphate and pitavastatin

In addition to their cholesterol-lowering effect, statins increase high-density lipoprotein cholesterol (HDL-C) levels. Endothelial lipase (EL) is a regulator of plasma HDL-C levels. In the present study, the effects of statins on EL expression were investigated.. The 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor pitavastatin suppressed basal and cytokine-treated EL expression in endothelial cells. Concomitant treatment with mevalonate or geranylgeranyl pyrophosphate completely reversed the inhibitory effect of pitavastatin, suggesting that geranylgeranylated proteins are involved in the inhibition of EL expression by statins. Inhibition of RhoA activity by overexpression of a dominant-negative mutant of RhoA or a Rho kinase inhibitor decreased EL levels. Pitavastatin reduced phospholipase activities of endothelial cells, and concomitant treatment with mevalonate reversed its inhibitory effect. Pitavastatin reduced RhoA activity and EL expression in mouse tissues. Furthermore, plasma EL concentrations in human subjects were measured by enzyme-linked immunosorbent assays. Plasma EL levels were negatively associated with plasma HDL levels in 237 patients with cardiovascular diseases, and pitavastatin treatment reduced plasma EL levels and increased HDL-C levels in 48 patients with hypercholesterolaemia.. These findings suggest that statins can reduce EL expression in vitro and in vivo via inhibition of RhoA activity. The inhibition of EL expression in the vessel wall may contribute to the anti-atherogenic effects of statins.

Topics: Adult; Aged; Aged, 80 and over; Animals; Cells, Cultured; Cholesterol, HDL; Dose-Response Relationship, Drug; Down-Regulation; Endothelial Cells; Enzyme-Linked Immunosorbent Assay; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Hypercholesterolemia; Lipase; Male; Mevalonic Acid; Mice; Mice, Inbred C57BL; Middle Aged; Polyisoprenyl Phosphates; Prospective Studies; Protein Kinase Inhibitors; Protein Prenylation; Quinolines; rho-Associated Kinases; rhoA GTP-Binding Protein; Time Factors; Transfection; Treatment Outcome

Phospholipase A2 (PLA2) changes the phosphatidylcholine contained in low-density lipoprotein (LDL) to lysophosphatidylcholine (LPC), which has various proatherogenic properties. We reported that tumor necrosis factor-alpha (TNFα) enhanced the expression of group V PLA2 (sPLA2-V) in human umbilical vein endothelial cells (HUVECs), and the LPC content in LDL and the monocyte chemoattractant protein-1 (MCP-1) expression were augmented when TNFα-stimulated HUVECs were incubated with LDL. Here, we observed that an HMG-CoA reductase inhibitor, pitavastatin, at the concentration of >1 μM administered 12 hours before TNFα stimulation suppressed the enhancement of sPLA2-V mRNA and protein. Pitavastatin also prevented the enhancement of the LPC content in LDL and the expression of MCP-1 mRNA when TNFα-stimulated HUVECs were incubated with LDL. The administration of geranylgeranyl pyrophosphate restored the expression of sPLA2-V mRNA and protein. The administration of the Rho kinase inhibitor Y-27632 and the transfection of small interfering RNA (siRNA) against sPLA2-V before TNFα stimulation both diminished the TNFα-induced sPLA2-V mRNA expression. Therefore, Y-27632 and siRNA against sPLA2-V also prevented the enhancement of MCP-1 mRNA expression when TNFα-stimulated HUVECs were incubated with LDL. Pitavastatin's inhibitory effect on the expression of sPLA2-V induced by TNFα may be useful to prevent the proatherogenic modification of LDL.

Topics: Amides; Chemokine CCL2; Human Umbilical Vein Endothelial Cells; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lipoproteins, LDL; Lysophosphatidylcholines; Phospholipases A2, Secretory; Polyisoprenyl Phosphates; Pyridines; Quinolines; RNA, Messenger; RNA, Small Interfering; Tumor Necrosis Factor-alpha

Epidemiological studies have shown that long-term treatment with statins decreases the risk of developing Alzheimer's disease. Statins have pleiotropic effects by lowering the concentration of isoprenoid intermediates. Although several studies have shown that statins may reduce amyloid beta protein levels, there have been few reports on the interaction between statins and tau. We report here that pitavastatin reduces total and phosphorylated tau levels in a cellular model of tauopathy, and in primary neuronal cultures. The decrease caused by pitavastatin is reversed by the addition of mevalonate, or geranylgeranyl pyrophosphate. The maturation of small G proteins, including RhoA was disrupted by pitavastatin, as was the activity of glycogen synthase kinase 3β (GSK3β), a major tau kinase. Toxin A, inhibitor of glycosylation of small G proteins, and Rho kinase (ROCK) inhibitor decreased phosphorylated tau levels. Rho kinase inhibitor also inactivated glycogen synthase kinase 3β. Although the mechanisms responsible for the reduction in tau protein by pitavastatin require further examination, this report sheds light on possible therapeutic approaches to tauopathy.

Topics: Animals; Bacterial Toxins; Cells, Cultured; Enterotoxins; Female; Glycogen Synthase Kinase 3; Glycogen Synthase Kinase 3 beta; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Male; Mevalonic Acid; Mice; Monomeric GTP-Binding Proteins; Neurons; Phosphorylation; Polyisoprenyl Phosphates; Quinolines; rho-Associated Kinases; tau Proteins

Statins have a neuroprotective effect in neurological diseases, a pleiotropic effect possibly related to blood-brain barrier (BBB) function. We investigated the effect of pitavastatin on barrier functions of an in vitro BBB model with primary cultures of rat brain capillary endothelial cells (RBEC). Pitavastatin increased the transendothelial electrical resistance (TEER), an index of barrier tightness of interendothelial tight junctions (TJs), at a concentration of 10(-8) M, and decreased the endothelial permeability for sodium fluorescein through the RBEC monolayer. The increase in TEER was significantly reduced in the presence of isoprenoid geranylgeranyl pyrophosphate, whereas farnesyl pyrophosphate had no effect on TEER. Our immunocytochemical and Western blot analyses revealed that treatment with pitavastatin enhanced the expression of claudin-5, a main functional protein of TJs. Our data indicate that pitavastatin strengthens the barrier integrity in primary cultures of RBEC. The BBB-stabilizing effect of pitavastatin may be mediated partly through inhibition of the mevalonate pathway and subsequent up-regulation of claudin-5 expression.

Topics: Animals; Biomarkers; Blood-Brain Barrier; Brain; Cell Membrane Permeability; Cells, Cultured; Claudins; Electric Impedance; Endothelial Cells; Fluorescent Antibody Technique; Gene Expression Regulation; Polyisoprenyl Phosphates; Quinolines; Rats; RNA, Messenger; Sesquiterpenes; Tight Junctions

Studies have indicated that protective effects of statins (HMG-CoA reductase inhibitor) are associated with the regulation of endothelial nitric oxide synthase (eNOS) or inducible NOS (iNOS) in heart and liver diseases. Statins have been reported to enhance hepatic NO production and decrease the vascular tone in patients with cirrhosis. However, it is unclear which NOS contributes to the increased NO production. We hypothesized that statins are involved in the up-regulation of iNOS in inflammatory liver, resulting in decreased hepatic resistance. Primary cultured rat hepatocytes were treated with pro-inflammatory cytokine interleukin (IL)-1beta in the presence or absence of pitavastatin. Pretreatment of cells with pitavastatin resulted in up-regulation of iNOS induction by IL-1beta, followed by increased NO production. Pitavastatin had no effects on the degradation of IkappaB or activation of NF-kappaB. However, pitavastatin super-induced the up-regulation of type I IL-1 receptor (IL-1RI), which is essential for iNOS induction in addition to the IkappaB/NF-kappaB pathway. Mevalonate and geranylgeranylpyrophosphate blocked the stimulatory effects of pitavastatin on iNOS and IL-1RI induction. Transfection experiments revealed that pitavastatin increased the stability of iNOS mRNA rather than its promoter transactivation. In support of this observation, pitavastatin increased the antisense-transcript corresponding to the 3'-UTR of iNOS mRNA, which stabilizes iNOS mRNA by interacting with the 3'-UTR- and RNA-binding proteins. These findings demonstrate that pitavastatin up-regulates iNOS by the stabilization of its mRNA, presumably through the super-induction of IL-1RI and antisense-transcript. This implies that statins may contribute to a novel potentiated treatment in liver injuries including cirrhosis.

Topics: Animals; Cells, Cultured; Hepatocytes; Humans; Interleukin-1beta; Male; Mevalonic Acid; Nitric Oxide Synthase Type II; Polyisoprenyl Phosphates; Quinolines; Rats; Rats, Wistar; Receptors, Interleukin-1 Type I; Recombinant Proteins; RNA Stability; RNA, Messenger; Time Factors; Up-Regulation

This study sought to induce the effect of nitric oxide (NO) production in vascular endothelial cells by Pitavastatin, which is a novel HMG-CoA reductase inhibitor (statin). The growth capacity of vascular endothelial cells significantly (p < 0.01) declined when stimulated with TNF-alpha (10 ng/ml). The growth capacity of the TNF-alpha treated cells recovered, when the TNF-alpha stimulation was performed after Pitavastatin (100 nM) pretreatment. The recovery of the growth capacity of the cells was suppressed by the presence of the NO synthase inhibitor, L-NAME. Pitavastatin increased NO production by the vascular endothelial cells in a dose and time dependent manner. The NO production was suppressed by the presence of mevalonic acid and geranylgeranyl pyrophosphate. In addition, the expression of endothelial nitric oxide synthase was strongly induced by Pitavastatin, and was suppressed by mevalonic acid and geranylgeranyl pyrophosphate by Western blot analysis. Our results show that Pitavastatin induces NO production by vascular endothelial cells, and protects vascular endothelial cells from injury due to the inflammatory reaction induced by TNF-alpha.

Topics: Cell Division; Cells, Cultured; Dose-Response Relationship, Drug; Endothelial Cells; Female; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Mevalonic Acid; NG-Nitroarginine Methyl Ester; Nitric Oxide; Nitric Oxide Synthase; Polyisoprenyl Phosphates; Quinolines; Time Factors; Tumor Necrosis Factor-alpha; Umbilical Veins

3-hydroxyl-3-methyl coenzyme A reductase inhibitors (statins) can function to protect the vasculature in a manner that is independent of their lipid-lowering activity. The main feature of the antithrombotic properties of endothelial cells is an increase in the expression of thrombomodulin (TM) without induction of tissue factor (TF) expression. We investigated the effect of statins on the expression of TM and TF by endothelial cells.. The incubation of endothelial cells with pitavastatin led to a concentration- and time-dependent increase in cellular TM antigen and mRNA levels. In contrast, the expression of TF mRNA was not induced under the same conditions. A nuclear run-on study revealed that pitavastatin accelerates TM transcription rate. The stimulation of TM expression by pitavastatin was prevented by either mevalonate or geranylgeranylpyrophosphate. Specific inhibition of geranylgeranyltransferase-I and Rac/Cdc42 by GGTI-286 and Clostridium sordellii lethal toxin, respectively, enhanced TM expression, whereas inactivation of Rho by Clostridium botulinum C3 exoenzyme was ineffective.. Statins regulate TM expression via inhibition of small G proteins of the Rho family; Rac/Cdc42. A statin-mediated increase in TM expression by endothelial cells may contribute to the beneficial effects of statins on endothelial function.

Topics: Bacterial Proteins; Bacterial Toxins; Cells, Cultured; Endothelium, Vascular; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Leucine; Mevalonic Acid; Monomeric GTP-Binding Proteins; Polyisoprenyl Phosphates; Quinolines; RNA, Messenger; Thrombomodulin; Thromboplastin; Umbilical Veins; Up-Regulation