Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.11.24 (mitogen-activated protein kinase)
95,810 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. 3-Hydroxy-3-methylglutaryl co-enzyme A reductase inhibitors (statins) prevent the progression of atherosclerosis by lowering cholesterol. However, the effect of statins on the synthesis of pro-inflammatory cytokines from endothelial cells has not yet been fully investigated. Here, we examined the effect of pravastatin, one of the statins, on IL-8 synthesis induced by thrombin in human aortic endothelial cells (AoEC) cultured with high glucose concentrations. 2. Pravastatin significantly decreased the IL-8 synthesis induced by thrombin. 3. Pravastatin inhibited the p44/42 MAP kinase activity induced by thrombin, but did not inhibit the p38 MAP kinase activity. 4. Translocation of ras protein from the cytosol to plasma membrane was inhibited by pravastatin. 5. Pravastatin inhibit the activator protein-1 activity, but did not inhibit the activation of IkappaB-alpha. 6. Dominant negative ras inhibited the p44/42 MAP kinase activity induced by PMA. 7. Our results suggest that pravastatin inhibits IL-8 synthesis by blocking the ras-MAP (p44/42) kinase pathway rather than nuclear factor-kappaB. Pravastatin may prevent atherosclerosis not only by lowering cholesterol levels, but also by suppressing IL-8 synthesis in AoEC through the inhibition of p44/42 MAP kinase, and this may be more beneficial in diabetic patients than in non-diabetics.
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PMID:Pravastatin suppresses the interleukin-8 production induced by thrombin in human aortic endothelial cells cultured with high glucose by inhibiting the p44/42 mitogen activated protein kinase. 1160 15

3-Hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase inhibitors (statins) are effective in patients with hypercholesterolemia to reduce risk of cardiovascular diseases, because of not only their lowering cholesterol effects but also their pleiotropic effects, such as improvement of endothelial cell dysfunction. On the other hand, statins prevent cell proliferation of various cells, including endothelial cells. We examined effects of all statins available at present on the viability of cultured rat pulmonary vein endothelial cells. Lovastatin, simvastatin, atorvastatin, fluvastatin and cerivastatin, which are hydrophobic statins, markedly reduced cell viability associated with DNA fragmentation, DNA laddering and activation of caspase-3, suggesting apoptotic cell death. Pravastatin, which is a hydrophilic statin, however, did not induce cell apoptosis. Apoptosis induced by hydrophobic statins was associated with activation of apoptosis-related intracellular signal transduction systems; attenuation of localization of RhoA to the membrane, induction of Rac1, and increase in phosphorylation of c-Jun N-terminal kinase and c-Jun. Endothelial cell apoptosis is underlying the improvement of the endothelial dysfunction with hydrophobic statins.
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PMID:All hydrophobic HMG-CoA reductase inhibitors induce apoptotic death in rat pulmonary vein endothelial cells. 1461 3

Statins have been shown to interact with several monocyte/macrophage functions. We tested the effect of pravastatin on transforming growth factor-beta1 (TGF-beta1) production and its possible involvement in scavenger receptors class A (SRA) expression in human THP-1 cells. TGF-beta1s biological activity in THP-1 cell conditioned medium, evaluated by luciferase activity of transfected cell with a TGF-beta responsive promoter, was increased in a dose-dependent manner after incubation with pravastatin (1-20 microM). Pravastatin (1-20 microM) induced a dose-dependent increase in TGF-beta1 mRNA expression and protein production in THP-1 cells. PMA-induced SRA gene and protein expression was suppressed by pravastatin with a mean 3-fold decrease at 10 microM. This last effect was reversed by a mouse monoclonal anti-TGF-beta1 neutralizing antibody. PD98059, a specific inhibitor of MAP kinase cascade, completely reversed pravastatin-induced SRA down-regulation. p44 and p42 isoforms showed a dose-dependent phosphorylation after treatment with pravastatin (1-20 microM) which was inhibited by a mouse monoclonal anti-TGF-beta1 antibody. Our results demonstrate that pravastatin significantly up-regulates TGF-beta1 expression which may be in involved in down-regulation of SRA expression in THP-1 cell cultures. A new pathway for pravastatin effects in atherogenesis can be suggested.
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PMID:Pravastatin up-regulates transforming growth factor-beta1 in THP-1 human macrophages: effect on scavenger receptor class A expression. 1474 92

Atheroma formation involves the movement of vascular smooth muscle cells (VSMC) into the subendothelial space. The aim of this study was to determine the involvement of PI3K and MAPK pathways and the importance of cross-talk between these pathways, in glucose-potentiated VSMC chemotaxis to serum factors. VSMC chemotaxis occurred in a serum gradient in 25 mmol/L glucose (but not in 5 mmol/L glucose) in association with increased phosphorylation (activation) of Akt and ERK1/2 in PI3K and MAPK pathways, respectively. Inhibitors of these pathways blocked chemotaxis, as did an mTOR inhibitor. VSMC expressed all class IA PI3K isoforms, but microinjection experiments demonstrated that only the p110beta isoform was involved in chemotaxis. ERK1/2 phosphorylation was reduced not only by MAPK pathway inhibitors but also by PI3K and mTOR inhibitors; when PI3K was inhibited, ERK phosphorylation could be induced by microinjected activated Akt, indicating important cross-talk between the PI3K and ERK1/2 pathways. Glucose-potentiated phosphorylation of molecules in the p38 and JNK MAPK pathways inhibited these pathways but did not affect chemotaxis. The statin, mevinolin, blocked chemotaxis through its effects on the MAPK pathway. Mevinolin-inhibited chemotaxis was restored by farnesylpyrophosphate but not by geranylgeranylpyrophosphate; in the absence of mevinolin, inhibition of farnesyltransferase reduced ERK phosphorylation and blocked chemotaxis, indicating a role for the Ras family of GTPases (MAPK pathway) under these conditions. In conclusion, glucose sensitizes VSMC to serum, inducing chemotaxis via pathways involving p110beta-PI3K, Akt, mTOR, and ERK1/2 MAPK. Cross-talk between the PI3K and MAPK pathways is necessary for VSMC chemotaxis under these conditions.
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PMID:Glucose-potentiated chemotaxis in human vascular smooth muscle is dependent on cross-talk between the PI3K and MAPK signaling pathways. 1524 75

Mevastatin which is an inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, the rate-limiting enzyme in cholesterol synthesis, suppress cell proliferation and induce apoptosis. However, the molecular mechanism of apoptosis induction is not well understood. So, in the present study, we attempted to clarify the mechanism by which mevastatin induces apoptosis in HL60 cells. It was found that mevastatin induced apoptosis. At that time, we observed an increase in caspase-3 activity and morphological fragmentation of the nuclei. The apoptosis induced by mevastatin was not inhibited by the addition of farnesyl pyrophosphate (FPP), squalene, ubiquinone, and isopentenyladenine, but was inhibited by the addition of geranylgeranyl pyrophosphate (GGPP). When we examined the survival signals at the time of apoptotic induction, we also observed that the administration of mevastatin had caused a remarkable decrease in the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2). However, other survival signals, such as nuclear factor kappa B (NF-kappaB), protein kinase B (Akt), and p38 mitogen-activated protein kinase (p38), exhibited no change. In addition, no quantitative change was observed in Bcl-2, which was an anti-apoptosis protein. It was also observed that apoptosis was induced when U0126, an MEK inhibitor, was added to the cells to inhibit ERK. These results suggested that mevastatin induced apoptosis when it inhibited GGPP biosynthesis and consequently decreased the level of phosphorylated ERK, which was a survival signal; moreover, at that time, there was no influence on NF-kappaB, Akt, p38, and Bcl-2. The results of this study also suggested that mevastatin could be used as an anticancer agent.
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PMID:Mevastatin induces apoptosis in HL60 cells dependently on decrease in phosphorylated ERK. 1578 22

Endometriosis is characterized by ectopic growth of endometrial tissues. Statins, inhibitors of 3-hydroxy-3methylglutaryl-coenzyme A reductase (HMGCR), have been shown to decrease proliferation of several mesenchymal tissues. Actions of statins may be related to decreased availability of cholesterol as well as intermediate metabolites of the mevalonate pathway downstream of HMGCR. This study was designed to evaluate effects of statins on growth of endometrial stromal cells and to investigate mechanisms of these effects. Human endometrial stromal cells were cultured in the absence and in the presence of serum and with or without mevastatin and simvastatin. DNA synthesis and viable cell numbers were determined. Effects of statins were also evaluated in the presence of mevalonate and squalene. Furthermore, effects on phosphorylation of mitogen-activated protein kinase 3/1 (MAPK3/1) (also known as extracellular signal-regulated kinase [ERK1/2]) were determined. Mevastatin and simvastatin induced a concentration-dependent inhibition of DNA synthesis and viable cell count in chemically defined media and in the presence of serum. Mevalonate, but not squalene, abrogated inhibitory effects of statins on cell proliferation. Statins inhibited MAPK3/1 phosphorylation. This is the first study demonstrating that statins inhibit growth of endometrial stromal cells. This effect is also demonstrable in the presence of a supply of cholesterol and may be related to decreased activation of MAPK3/1. The present observations may be relevant to potential therapeutic use of statins in conditions such as endometriosis.
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PMID:Statins inhibit growth of human endometrial stromal cells independently of cholesterol availability. 1657 71

Insulin can generate oxygen free radicals. Statins, 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors, exert a powerful antioxidant effect. The present study aimed to clarify the mechanisms through which insulin generates free radicals and to assess whether pravastatin modulates such effects. In cultured skin fibroblasts from human volunteers exposed to high insulin concentration, either in the presence or in the absence of pravastatin, insulin induced translocation of the p47(phox) subunit of NAD(P)H oxidase from the cytosol to the membrane and generation of radical oxygen species through a PKC delta-dependent mechanism. The insulin-induced translocation of p47(phox) was PKC delta dependent and attenuated by pravastatin, but independent of the activation of Akt and Rac1. Insulin-induced Akt phosphorylation was increased by pravastatin and ERK1/2 phosphorylation attenuated. The present study demonstrates a novel mechanism by which insulin stimulates the generation of free radicals in human fibroblasts, ex vivo. It involves phosphatidylinositol 3-kinase, PKC delta, and p47(phox) translocation and promotes ERK1/2 phosphorylation. Pravastatin inhibited radical oxygen species production by inhibiting PKC delta. These observations offer a robust explanation for the positive effects of pravastatin treatment in patients with insulin resistance syndrome.
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PMID:Insulin generates free radicals in human fibroblasts ex vivo by a protein kinase C-dependent mechanism, which is inhibited by pravastatin. 1684 28

Expression of functionally active thrombomodulin (TM) on the luminal surface of endothelial cells is critical for vascular thromboresistance. The 3-hydroxyl-3-methyl coenzyme A reductase inhibitor, pravastatin, can protect the vasculature in a manner that is independent of its lipid-lowering activity. We examined the effect of pravastatin on TM expression by human aortic endothelial cells (HAECs) with subsequent tumor necrosis factor alpha (TNFalpha) stimulation and investigated the signaling pathways involved. TNFalpha treatment attenuated TM expression in HAECs in a time-dependent manner. Pravastatin upregulated TM levels in TNFalpha-treated HAECs. Specific inhibition of geranylgeranyltransferase-I or the Rho family by GGTI-286 or TcdB, respectively, enhanced TM expression in TNFalpha-treated HAECs, whereas MAP kinase inhibitors, inactivation of Rho by Clostridium botulinum C3 exoenzyme, or the Rho kinase inhibitor, Y-27632, had no effect. In TNFalpha-treated HAECs, pravastatin inhibited Rac1 and Cdc42 activation and their translocation to the cell membrane. Blocking the transcriptional activation of NF-kappaB prevented the TNFalpha-induced downregulation of TM. The pravastatin-induced increase in TM expression in TNFalpha-treated HAECs was mediated through inhibition of NF-kappaB activation. Pravastatin regulates TM expression by inhibiting the activation of the Rho family proteins, Rac1 and Cdc42, and the transcription factor, NF-kappaB. The increase in endothelial TM activity in response to pravastatin constitutes a novel pleiotropic (nonlipid-related) effect of this commonly used compound and may be of clinical significance in disorders in which deficient endothelial TM plays a pathophysiological role.
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PMID:Pravastatin induces thrombomodulin expression in TNFalpha-treated human aortic endothelial cells by inhibiting Rac1 and Cdc42 translocation and activity. 1721 35

This study investigated the protective effects of pravastatin against cisplatin-induced nephrotoxicity and the possible mechanisms in mice. Pravastatin showed significant protection as evidenced by the decrease of elevated serum creatinine (CRE) and blood urea nitrogen (BUN), and improvement of histopathological injury induced by cisplatin. The formation of kidney malondialdehyde (MDA) with a concomitant reduction of reduced glutathione (GSH) were inhibited by pravastatin, while the activities of kidney superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-px) were increased. The over expressions of kidney induced nitric oxide synthase (iNOS) and nitrotyrosine (3-NT) were suppressed by pravastatin. Pravastatin suppressed cisplatin-induced p38 mitogen-activated protein kinase (MAPK) activation in the kidney of mice. These results suggest that pravastatin pre-administration can prevent the nephrotoxicity induced by cisplatin. Pravastatin may exert the protective effect via inhibiting oxidative and nitrosative stress.
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PMID:Amelioration of cisplatin-induced nephrotoxicity by pravastatin in mice. 2006 Jun 96

Reactive oxygen species (ROS) are important intracellular signaling molecules and are implicated in cardioprotective pathways including ischemic preconditioning. Statins have been shown to have cardioprotective effects against ischemia/reperfusion injury, however, the precise mechanisms remain to be elucidated. We hypothesized that ROS-mediated signaling cascade may be involved in pravastatin-induced cardioprotection. Cultured rat cardiomyocytes were exposed to H(2)O(2) for 30 min to induce cell injury. Pravastatin significantly suppressed H(2)O(2)-induced cell death evaluated by propidium iodide staining and the MTT assay. Incubation with pravastatin activated catalase, and prevented a ROS burst induced by H(2)O(2), which preserved mitochondrial membrane potential. Protective effects were induced very rapidly within 10 min, which was concordant with the up-regulation of phosphorylated ERK1/2. L-NAME, 5HD, N-acetylcysteine (NAC) and staurosporine inhibited ERK1/2 phosphorylation and also reduced pravastatin-induced cardioprotection, suggesting NO, mitochondrial K(ATP) (mitoK(ATP)) channels, ROS and PKC should be involved in the cardioprotective signaling. We also demonstrated that pravastatin moderately up-regulated ROS generation in a 5HD-inhibitable manner. In isolated perfused rat heart experiments, pravastatin administered 10 min prior to no-flow global ischemia significantly improved left ventricular functional recovery, and also reduced infarct size, which were attenuated by the treatment with NAC, 5HD, L-NAME or staurosporine. Administration of pravastatin from the beginning of reperfusion also conferred cardioprotection. Pravastatin protected the cardiomyocytes against oxidative stress by preventing the ROS burst and preserving mitochondrial function. Moderately up-regulated ROS production by mitoK(ATP) channels opening is involved in the pro-survival signaling cascade activated by pravastatin.
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PMID:Mitochondrial K(ATP) channels-derived reactive oxygen species activate pro-survival pathway in pravastatin-induced cardioprotection. 2015 Nov 95


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