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: UNIPROT:Q8NEX9 (reductase)
26,410 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypercholesterolemia is considered an important risk factor in coronary artery disease. Thus the possibility of controlling de novo synthesis of endogenous cholesterol, which is nearly two-thirds of total body cholesterol, represents an effective way of lowering plasma cholesterol levels. Statins, fungal secondary metabolites, selectively inhibit hydroxymethyl glutaryl-coenzyme A (HMG-CoA) reductase, the first enzyme in cholesterol biosynthesis. The mechanism involved in controlling plasma cholesterol levels is the reversible inhibition of HMG-CoA reductase by statins, related to the structural similarity of the acid form of the statins to HMG-CoA, the natural substrate of the enzymatic reaction. Currently there are five statins in clinical use. Lovastatin and pravastatin (mevastatin derived) are natural statins of fungal origin, while symvastatin is a semi-synthetic lovastatin derivative. Atorvastatin and fluvastatin are fully synthetic statins, derived from mevalonate and pyridine, respectively. In addition to the principal natural statins, several related compounds, monacolins and dihydromonacolins, isolated fungal intermediate metabolites, have also been characterized. All natural statins possess a common polyketide portion, a hydroxy-hexahydro naphthalene ring system, to which different side chains are linked. The biosynthetic pathway involved in statin production, starting from acetate units linked to each other in head-to-tail fashion to form polyketide chains, has been elucidated by both early biogenetic investigations and recent advances in gene studies. Natural statins can be obtained from different genera and species of filamentous fungi. Lovastatin is mainly produced by Aspergillus terreus strains, and mevastatin by Penicillium citrinum. Pravastatin can be obtained by the biotransformation of mevastatin by Streptomyces carbophilus and simvastatin by a semi-synthetic process, involving the chemical modification of the lovastatin side chain. The hypocholesterolemic effect of statins lies in the reduction of the very low-density lipoproteins (VLDL) and LDL involved in the translocation of cholesterol, and in the increase in the high-density lipoproteins (HDL), with a subsequent reduction of the LDL- to HDL-cholesterol ratio, the best predictor of atherogenic risk. The use of statins can lead to a reduction in coronary events related to hypercholesterolemia, but the relationship between benefit and risk, and any possible interaction with other drugs, must be taken into account.
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PMID:Biosynthesis and biotechnological production of statins by filamentous fungi and application of these cholesterol-lowering drugs. 1195 37

Type IIB hyperlipidemia is associated with premature vascular disease, an atherogenic lipoprotein phenotype characterised by elevated levels of triglyceride-rich VLDL and small dense LDL, together with subnormal levels of HDL. The dose-dependent and independent effects of a potent HMGCoA reductase inhibitor, Atorvastatin, at daily doses of 10 and 40 mg, were evaluated on triglyceride-rich lipoprotein subclasses (VLDL-1, VLDL-2 and IDL), on the major LDL subclasses (light LDL, LDL-1+LDL-2, D: 1.019-1.029 g/ml; intermediate LDL, LDL-3, D: 1.029-1.039 g/ml and small dense LDL, LDL-4+LDL+5, D: 1.039-1.063 g/ml), on CETP-mediated cholesteryl ester transfer from HDL to apoB-containing lipoproteins, on phospholipid transfer protein activity and on plasma-mediated cellular cholesterol efflux in patients (n=10) displaying type IIB hyperlipidemia. Plasma concentrations of triglyceride-rich lipoprotein subclasses (TRL: VLDL-1, Sf 60-400; VLDL-2, Sf 20-60 and IDL, Sf 12-20) and of LDL (D: 1.019-1.063 g/ml) were markedly diminished after 6 weeks of statin treatment at 10 mg per day (-31 and -36%, respectively; P<0.002) and by 42 and 51%, respectively at the 40 mg per day dose. Increasing doses of atorvastatin progressively normalised both the quantitative and qualitative features of the LDL subclass profile, in which dense LDL predominated at baseline. Indeed, dense LDL levels were reduced by up to 57% at the 40-mg dose, leading to a shift in the peak of the density profile towards larger, buoyant LDL particles typical of normolipidemic subjects. In addition, marked reduction in numbers of apoB100-containing particle acceptors led to a 30% decrease (P<0.02) in CETP-mediated CE transfer from HDL. Finally, a significant dose-dependent statin-mediated elevation (+15% at 10 mg; P=0.0003 and +35% at 40 mg; P<0.0001 compared to baseline) in the capacity of plasma from type IIB subjects to mediate free cholesterol efflux from Fu5AH hepatoma cells was observed. Moreover, atorvastatin (40 mg per day) significantly increased plasma apoAI levels (+24%; P<0.05), thereby suggesting that this statin enhances production of apoAI and with it, formation of nascent pre-beta HDL particles. Plasma PLTP activity was not affected by either dose of atorvastatin. We conclude that increasing the dose of atorvastatin leads to dose-dependent, preferential and progressive reduction in particle numbers of atherogenic VLDL-2, IDL and dense LDL, and concomitantly, to enhanced cellular cholesterol efflux in type IIB dyslipidemia, thereby diminishing the atherosclerotic burden in subjects characterised by high cardiovascular risk.
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PMID:Dose-dependent action of atorvastatin in type IIB hyperlipidemia: preferential and progressive reduction of atherogenic apoB-containing lipoprotein subclasses (VLDL-2, IDL, small dense LDL) and stimulation of cellular cholesterol efflux. 1205 75

Treatments with high doses of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors may induce the expression of sterol regulatory element binding protein (SREBP)-target genes, causing different effects from those attributed to the reduction of hepatic cholesterol content. The aim of this study was to investigate the effects of high doses of statins on the key enzymes involved in VLDL production in normolipidemic rats. To examine whether the effects caused by statin treatment are a consequence of HMG-CoA reductase inhibition, we tested the effect of atorvastatin on these enzymes in mevalonate-fed rats. Atorvastatin and simvastatin enhanced not only HMG-CoA reductase but also the expression of the SREBP-2 gene itself. As a result of the overexpression of SREBP-2 caused by the statin treatment, genes regulated basically by SREBP-1, as FA synthase and acetyl-coenzyme A carboxylase, were also induced and their mRNA levels increased. DAG acyltransferase and microsomal TG transfer protein mRNA levels as well as phosphatidate phosphohydrolase activity were increased by both statins. Simvastatin raised liver cholesterol content, ACAT mRNA levels, and CTP:phosphocholine cytidylyltransferase activity, whereas it reduced liver DAG and phospholipid content. Mevalonate feeding reversed all changes induced by the atorvastatin treatment. These results show that treatment with high doses of statins induces key enzymes controlling rat liver lipid synthesis and VLDL assembly, probably as a result of SREBP-2 overexpression. Despite the induction of the key enzymes involved in VLDL production, both statins markedly reduced plasma TG levels, suggesting that different mechanisms may be involved in the hypotriglyceridemic effect of statins at high or low doses.
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PMID:High doses of atorvastatin and simvastatin induce key enzymes involved in VLDL production. 1205 85

Atorvastatin is a drug of choice in the treatment of coronary heart disease, because this hepatic 3-hydroxy-3-methylglutaryl coenzyme reductase inhibitor significantly decreases plasma cholesterol and triglyceride levels. However, little is known about the underlying molecular targets of this drug. Lipoprotein lipase (LPL), an enzyme with multiple functions in non-hepatic lipid metabolism, may be a potential candidate and LPL gene expression may increase in response to a treatment with atorvastatin. In order to verify this hypothesis, mouse 3T3-L1 preadipocytes were incubated with 1 and 10 micromol/l atorvastatin for 24 and 48 h and LPL mRNA concentration was measured by reverse transcription-polymerase chain reaction. Our data indicated that atorvastatin increased LPL mRNA concentration by a time- and dose-dependent mechanism. LPL mRNA concentration was significantly increased by 82% with 10 micromol/l atorvastatin after 48 h. LPL mRNA concentration was 28% greater (not significant) than control with 10 micromol/l atorvastatin after 24 h. No increase was obtained with 1 micromol/l atorvastatin after 24 or 48 h. The first 976 nucleotides of rat LPL promoter were transfected in 3T3-L1 preadipocytes. Addition of 10 micromol/l atorvastatin for 48 h resulted in a 44% increase of rat LPL promoter activity. This study demonstrates for the first time that a statin can regulate LPL gene expression transcriptionally in preadipocytes.
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PMID:Induction of lipoprotein lipase gene expression in 3T3-L1 preadipocytes by atorvastatin, a cholesterol- and triglyceride-lowering drug. 1216 66

The triglyceride-lowering effect of pitavastatin, a potent 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor, was investigated in a rat model of postprandial lipemia. Plasma triglyceride levels started to increase 4 h after the fat load, reached the maximum at 6 h and then gradually decreased. A single dose of pitavastatin (1 mg/kg) significantly suppressed chylomicron-triglyceride secretion into the lymph by 40% and delayed the elevation of plasma triglyceride. Pitavastatin at 1 mg/kg decreased the 6-h plasma triglyceride levels by 53% and at 0.5 mg/kg decreased the 0-12 h area under the curve (AUC) of triglyceride levels by 56%. Atorvastatin also caused decreases, but to a lesser extent. Pitavastatin, and atorvastatin to a lesser extent, reduced the activity of the intestinal microsomal triglyceride transfer protein (MTP) at 6 h. These results suggested that a single dose of pitavastatin lowered postprandial triglyceride levels in rats by decreasing chylomicron-triglyceride secretion, probably through a reduction of intestinal MTP activity and triglyceride droplet formation in the endoplasmic reticulum.
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PMID:Triglyceride-lowering effect of pitavastatin [corrected] in a rat model of postprandial lipemia. 1219 89

Statins, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors, which are approved for cholesterol reduction, may also be beneficial in the treatment of inflammatory diseases. Atorvastatin (Lipitor) was tested in chronic and relapsing experimental autoimmune encephalomyelitis, a CD4(+) Th1-mediated central nervous system (CNS) demyelinating disease model of multiple sclerosis. Here we show that oral atorvastatin prevented or reversed chronic and relapsing paralysis. Atorvastatin induced STAT6 phosphorylation and secretion of Th2 cytokines (interleukin (IL)-4, IL-5 and IL-10) and transforming growth factor (TGF)-beta. Conversely, STAT4 phosphorylation was inhibited and secretion of Th1 cytokines (IL-2, IL-12, interferon (IFN)-gamma and tumour necrosis factor (TNF)-alpha) was suppressed. Atorvastatin promoted differentiation of Th0 cells into Th2 cells. In adoptive transfer, these Th2 cells protected recipient mice from EAE induction. Atorvastatin reduced CNS infiltration and major histocompatibility complex (MHC) class II expression. Treatment of microglia inhibited IFN-gamma-inducible transcription at multiple MHC class II transactivator (CIITA) promoters and suppressed class II upregulation. Atorvastatin suppressed IFN-gamma-inducible expression of CD40, CD80 and CD86 co-stimulatory molecules. l-Mevalonate, the product of HMG-CoA reductase, reversed atorvastatin's effects on antigen-presenting cells (APC) and T cells. Atorvastatin treatment of either APC or T cells suppressed antigen-specific T-cell activation. Thus, atorvastatin has pleiotropic immunomodulatory effects involving both APC and T-cell compartments. Statins may be beneficial for multiple sclerosis and other Th1-mediated autoimmune diseases.
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PMID:The HMG-CoA reductase inhibitor, atorvastatin, promotes a Th2 bias and reverses paralysis in central nervous system autoimmune disease. 1242 6

We investigated the effects of atorvastatin, a widely used 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, and BMS-201038, a microsomal triglyceride transfer protein (MTP) inhibitor, in sucrose-fed hypertriglyceridemic rats to determine whether the activation of beta-oxidation by these compounds plays a role in their hypotriglyceridemic effect. The decrease in plasma triglyceride concentration and post-Triton very low-density lipoprotein (VLDL) triglyceride concentration, a measure of hepatic triglyceride secretion, by atorvastatin (30 mg/kg p.o.) for 2 weeks was to approximately the same degree as those by BMS-201038 (0.3 mg/kg). Atorvastatin (30 mg/kg) increased hepatic beta-oxidation activity by 54% (P < 0.01), while BMS-201038 (0.3 mg/kg) had no significant effect. Atorvastatin decreased hepatic triglyceride, fatty acid and cholesteryl ester concentrations by 21% to 39%, whereas BMS-201038 increased these variables by 28% to 307%. In the atorvastatin-treated groups, a significant relationship was seen not only between hepatic beta-oxidation activity and hepatic triglyceride concentration (R(2) = 0.535, P < 0.01), but also between hepatic and plasma triglyceride concentrations (R(2) = 0.586, P < 0.01). No effect of atorvastatin on hepatic fatty acid synthesis was observed. These results indicate that the activation of hepatic beta-oxidation by atorvastatin may contribute to the decrease in hepatic triglyceride concentration, leading to its hypotriglyceridemic effect.
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PMID:Atorvastatin increases hepatic fatty acid beta-oxidation in sucrose-fed rats: comparison with an MTP inhibitor. 1244 82

We demonstrate that the 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG-CoA) reductase inhibitors atorvastatin and simvastatin enhance functional outcome and induce brain plasticity when administered after stroke to rats. With atorvastatin treatment initiated 1 day after stroke, animals exhibited significant increases in vascular endothelial growth factor, cyclic guanosine monophosphate, angiogenesis, endogenous cell proliferation and neurogenesis, and an increase in the synaptic protein, synaptophysin. Atorvastatin-induced angiogenesis in a tube formation assay was reduced by an antibody against the vascular endothelial growth factor receptor 2 (FIK-1) and by the nitric oxide synthase inhibitor, N-mono-methyl-L-arginine (L-NAME). Atorvastatin also induced phosphorylation of Akt and Erk in cultured primary cortical neurons. These data indicate that atorvastatin induced brain plasticity and has neurorestorative activity after experimental stroke.
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PMID:Statins induce angiogenesis, neurogenesis, and synaptogenesis after stroke. 1278 20

Statins, 3-hydroxy-3 methylglutaryl coenzyme A(HMG-CoA) reductase inhibitors, are approved for cholesterol reduction and are commonly used to treat atherosclerosis and coronary disease. Statins may also be potent immunomodulatory agents and be beneficial in the treatment of autoimmune diseases. Statins have already been used to reduce the rejection of human heart transplants by the immune system, and there have been reports of a protective effect of injected statins in models of brain autoimmunity similar to experimental autoimmune encephalomyelitis. In vitro studies in multiple sclerosis(MS) revealed that statins reduced the expression of activation-induced adhesion molecules on T cells, modified Th1/Th2 cytokine balance, reduced matrix metalloproteinase(MMP)-9, and downregulated chemokine receptors on both B and T cells. Thus statins are effective immunomodulators in vitro that merit evaluation as treatment for MS. In vivo studies using three different animal models of MS revealed that oral atorvastatin prevented or reversed chronic and relapsing paralysis. Atorvastatin has been shown to have pleiotropic immunomodulatory effects involving both antigen presenting cells and T cell compartment. Thus, statins may be beneficial for MS, and clinical trials of the effects of statins on MS are now in progress, hopefully in a favorable way.
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PMID:[Effects of atorvastatin in multiple sclerosis]. 1296 38

Atorvastatin, a second generation synthetic 3-hydroxy 3-methylglutaryl-coenzyme-A (HMG-CoA) reductase inhibitor used in the treatment of hypercholesterolemia, reduces both intracellular cholesterol synthesis and serum cholesterol levels, and this could have a potential negative impact on gonadal and adrenal steroidogenesis. Hypercholesterolemia in type 2 diabetes, even when mild, must be treated in an aggressive way, due to the more strict therapeutic goals than in the non diabetic population. Since the wide use of 3-hydroxy 3-methylglutaryl-coenzyme-A (HMG-CoA) reductase inhibitor (statins) in type 2 diabetes, the main aim of our study was to evaluate the effects of "therapeutic" doses of atorvastatin on gonadal and adrenal hormones in 24 type 2 diabetic patients (16 males and 8 postmenopausal females), with mild to moderate hypercholesterolemia (LDL-cholesterol = 150.1 +/- 32.0 and 189.9 +/- 32.9 mg/dl, respectively) studied before and after a 3 months treatment with atorvastatin (20 mg/day). In all patients, lipids and serum cortisol, dehydroepiandrosterone sulphate (DHEA-S), androstendione and sex hormone binding globulin (SHBG) were measured, with the addition, only in males, of testosterone and free testosterone index. After atorvastatin treatment a significant decrease in total and LDL cholesterol was observed (p < 0.05), while HDL-cholesterol did not significantly change ( p = N.S.), as no significant difference was found between steroid hormones measured before and after atorvastatin either in male and females. In conclusion, our data suggest that, in type 2 diabetic patients, the use of atorvastatin has no clinically important effects on either gonadal or adrenal steroid hormones.
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PMID:Atorvastatin treatment does not affect gonadal and adrenal hormones in type 2 diabetes patients with mild to moderate hypercholesterolemia. 1456 85


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