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1.
2.
3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (i.e. statins) are currently under clinical investigation as a prophylactic immunomodulatory treatment for neurological diseases where an inflammatory disruption of the blood-brain barrier plays a pathogenic role. Here, we investigated whether atorvastatin pre-treatment modulates inflammatory-induced barrier dysfunction of cultured human brain microvascular endothelial cells (HBMEC). Pre-treatment of immortalized HBMEC with atorvastatin (50 nmol/L to 1 micromol/L) dose-dependently prevented an inflammatory up-regulation of monocyte chemoattractant protein-1/CCL2 but not of interleukin-8/CXCL8 and intercellular adhesion molecule-1 expression by tumor necrosis factor-alpha or interleukin-1beta. It antagonized an inflammatory up-regulation of claudin-3 expression while zonula occludens-1 and occludin protein levels remained unaltered. Like immortalized HBMEC, primary HBMEC also showed a reduction of claudin-3 and of inducible CCL2 expression following atorvastatin pre-treatment. On a functional level, atorvastatin pre-treatment of HBMEC strongly and dose-dependently reduced adhesion of activated T lymphocytes to pre-activated primary endothelium. Atorvastatin effects could partially be abolished by parallel mevalonate treatment. These anti-inflammatory effects of atorvastatin were observed already at a pharmacologically relevant concentration of 50 nmol/L. Our results obtained with human brain endothelial cells demonstrate how statins may partially prevent an inflammatory-mediated blood-brain barrier breakdown in humans.  相似文献   

3.
Targeted drug delivery platforms can increase the concentration of drugs in specific cell populations, reduce adverse effects, and hence improve the therapeutic effect of drugs. Herein, we designed two conjugates by installing the targeting ligand GalNAc (N-acetylgalactosamine) onto atorvastatin (AT). Compared to the parent drug, these two conjugates, termed G2-AT and G2-K-AT, showed increased hepatic cellular uptake. Moreover, both conjugates were able to release atorvastatin, and consequently showed dramatic inhibition of β-hydroxy-β-methylglutaryl-CoA (HMG-CoA) reductase and increased LDL receptors on cell surface.  相似文献   

4.
Epidemiological studies indicate that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, play a role in inhibition of several human neoplasia including breast cancer. In this study, chemopreventive effects of atorvastatin in N-methyl-N-nitrosourea-induced mammary carcinogenesis in female rats were evaluated. Atorvastatin was administered in the diet at two concentrations: 10 mg/kg (ATOR 10) and 100 mg/kg (ATOR 100). Atorvastatin treatment began 8 days prior to carcinogen administration and subsequently continued for 15 weeks till the end of the experiment. Atorvastatin at a higher dose suppressed tumor frequency by 80.5% (P = 0.0008) and tumor incidence by 49.5% (P = 0.015), and extended latency period by 14 days (P = 0.076) when compared to the control group. Atorvastatin at a lower dose did not significantly alter tumor parameters in comparison with the control group. In the specimens of mammary tumors, atorvastatin (in the ATOR 100 group) significantly decreased mRNA expression of Bcl-2 gene but non-significantly increased Bax mRNA expression compared to control group. Atorvastatin administration did not alter serum concentration of triacylglycerols, total cholesterol, and LDL cholesterol in comparison with controls. This study is the first report on tumor suppressive effect of atorvastatin in rat mammary carcinogenesis.  相似文献   

5.
Rho GTPases orchestrate signaling pathways leading to cell migration. Their function depends on GTP loading and isoprenylation by geranylgeranyl pyrophosphate (GGpp). In this study, we show that in human T cells, geranylgeranylation-and not GTP loading-is necessary for RhoA-mediated downstream events. As a result of GGpp depletion with the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor atorvastatin, RhoA was sequestered from the membrane to the cytosol and, notwithstanding increased GTP loading, the constitutive activation of its substrate Rho-associated coiled-coil protein kinase-1 was blocked. In line with this, T cells expressing increased GTP-RhoA failed to form an intact cytoskeleton and to migrate toward a chemokine gradient. In vivo treatment with atorvastatin in the rodent model of multiple sclerosis markedly decreased the capacity of activated T cells to traffic within the brain, as demonstrated by multiphoton analysis. Thus, tethering of RhoA to the membrane by GGpp is determinant for T cell migration and provides a mechanism for preventing T cell infiltration into inflamed compartments by 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors.  相似文献   

6.
Pregnant rats were given pharmacological doses of cortisol or ACTH or no hormone from gestation day 9 to 19 and maternal and fetal hepatic 3-hydroxy-3-methylglutaryl-CoA reductase activity and plasma cholesterol studied on gestation day 20. Reductase activity was also studied in the maternal and fetal adrenal of the rats given cortisol or no hormone. Cortisol administration increased the maternal and fetal plasma cholesterol but had no effect on the hepatic active (phosphorylated) 3-hydroxy-3-methylglutaryl-CoA reductase activity when compared to untreated rats. Total (active + inactive) 3-hydroxy-3-methylglutaryl-CoA reductase activity, however, was reduced in maternal liver but not altered in the fetal liver by cortisol. The maternal cortisol treatment decreased the fetal, but not maternal, adrenal 3-hydroxy-3-methylglutaryl-CoA reductase total enzyme activity. The data support a hypothesis that utilization of plasma cholesterol for adrenal steroidogenesis may be an important determinant of plasma cholesterol homeostasis in the rat fetus. Maternal ACTH administration increased the foetal but not maternal plasma cholesterol, whilst active 3-hydroxy-3-methylglutaryl-CoA reductase activity was increased in the pregnant rat but not her fetuses. This result may suggest coordination of hepatic active reductase activity with adrenal cholesterol utilization in the pregnant rat. The reason for the fetal hypercholesterolaemia caused by ACTH, which is not known to cross the placenta, is uncertain. The studies, however, indicate that fetal cholesterol homeostasis and the rate limiting enzyme of cholesterol synthesis is influenced by maternal glucocorticoid administration.  相似文献   

7.
Oxygen–glucose deprivation (OGD) in brain cells increases extracellular glutamate concentration leading to excitotoxicity. Glutamate uptake from the synaptic cleft is carried out by glutamate transporters, which are likely to be modulated by oxidative stress. Therefore, oxidative stress is associated with reduced activity of glutamate transporters and glutamine synthetase, thus increasing extracellular glutamate levels that may aggravate damage to brain cells. Atorvastatin, a cholesterol-lowering agent, has been shown to exert neuroprotective effects. The aim of this study was to investigate if in vivo atorvastatin treatment would have protective effects against hippocampal slices subjected to OGD, ex vivo. Atorvastatin pretreatment promoted increased cell viability after OGD and reoxygenation of hippocampal slices. Atorvastatin-induced neuroprotection may be related to diminished oxidative stress, since it prevented OGD-induced decrement of non-proteic thiols (NPSH) levels and increase in the production of reactive oxygen species (ROS). Atorvastatin pretreatment also prevented the OGD-induced decrease in glutamate uptake and glutamine synthetase activity, although it had no effect on OGD-induced excitatory aminoacids release. Addition of cholesterol before OGD and reoxygenation, abolished the protective effect of atorvastatin on cellular viability as well as on glutamate uptake and glutamine synthetase activity. Therefore, atorvastatin is capable of preventing OGD-induced cell death, an effect achieved due to modulation of glutamate uptake and glutamine synthetase activity, and associated with diminished oxidative stress. Additionally, atorvastatin effects were dependent on its action on cholesterol synthesis inhibition. Thus, atorvastatin might be a useful strategy in the prevention of glutamate exitotoxicity involved in brain injuries such as vascular disorders.  相似文献   

8.
C-6 glioma cells, grown in medium supplemented with 5% delipidated foetal calf serum, were induced to enter a quiescent state by removing serum from the medium. Within 24h there was a 75–80% decline in the rate of incorporation of [14C]acetate or 3H2O into digitonin-precipitable sterols. Experiments with [3H]mevalonolactone as a labelled sterol precursor suggested that the decline in sterol synthesis was regulated primarily at a point in the pathway before the formation of mevalonate. The specific activities of 3-hydroxy-3-methylglutaryl-CoA synthase and 3-hydroxy-3-methylglutaryl-CoA reductase decreased sharply in conjunction with the decline in sterol synthesis in the serum-free cultures; however, the activity of acetoacetyl-CoA thiolase was altered only slightly. The magnitude of the initial decline in reductase activity was not affected when 50-mm-NaF was included in the preincubation and assay buffers to prevent activation of physiologically inactive enzyme. However, after 6h of serum deprivation the decline in 3-hydroxy-3-methylglutaryl-CoA reductase activity was due to a decrease in the amount of latent activity. The sterol concentration in C-6 cells was unchanged after 24h in serum-free medium, although a 20% decrease in the sterol/fatty acid molar ratio occurred as a result of a small increase in the fatty-acid concentration. Incorporation of 3H2O into fatty acids was inhibited in the serum-deprived glial cells; however, this inhibition developed more slowly and was not as pronounced as the diminution in sterol synthesis. The results suggest that in C-6 glia, which resemble the glial stem cells of the developing brain, the decreased demand for membrane sterols in the quiescent state results in a decline in sterol synthesis, mediated primarily through co-ordinate changes in the activities of 3-hydroxy-3-methylglutaryl-CoA synthase and 3-hydroxy-3-methylglutaryl-CoA reductase.  相似文献   

9.
The mechanism by which platelet-derived growth factor (PDGF) regulates vascular smooth muscle cell (SMC) DNA synthesis is unknown, but may involve isoprenoid intermediates of the cholesterol biosynthetic pathway. Inhibition of isoprenoid synthesis with the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, simvastatin (Sim, 1-10 microM), inhibited PDGF-induced SMC DNA synthesis by >95%, retinoblastoma gene product hyperphosphorylation by 90%, and cyclin-dependent kinases (cdk)-2, -4, and -6 activity by 80 +/- 5, 50 +/- 3, and 48 +/- 3%, respectively. This correlated with a 20-fold increase in p27(Kip1) without changes in p16, p21(Waf1), or p53 levels compared with PDGF alone. Since Ras and Rho require isoprenoid modification for membrane localization and are implicated in cell cycle regulation, we investigated the effects of Sim on Ras and Rho. Up-regulation of p27(Kip1) and inhibition of Rho but not Ras membrane translocation by Sim were reversed by geranylgeranylpyrophosphate, but not farnesylpyrophosphate. Indeed, inhibition of Rho by Clostridium botulinum C3 transferase or overexpression of dominant-negative N19RhoA mutant increased p27(Kip1) and inhibited retinoblastoma hyperphosphorylation. In contrast, activation of Rho by Escherichia coli cytotoxic necrotizing factor-1 decreased p27(Kip1) and increased SMC DNA synthesis. These findings indicate that the down-regulation of p27(Kip1) by Rho GTPase mediates PDGF-induced SMC DNA synthesis and suggest a novel direct effect of 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors on the vascular wall.  相似文献   

10.
To determine whether neurite outgrowth depends upon the mevalonate pathway, we blocked mevalonate synthesis in nerve growth factor-treated PC12 cells or primary cortical neurones with atorvastatin, a 3-hydroxymethylglutaryl coenzyme A (HMG-CoA) reductase inhibitor, and substituted different intermediates of the mevalonate pathway. We show that HMG-CoA reductase inhibition causes a profound reduction of neurite length, neurite loss and ultimatively cell death in undifferentiated and pre-differentiated PC12 cells and also in rat primary cortical neurones. Geranylgeranylpyrophosphate, but not farnesylpyrophosphate, squalene or cholesterol, completely compensated for the lack of mevalonate. Our data indicate that, under HMG-CoA reductase inhibition, geranylgeranylpyrophosphate rather than farnesylpyrophosphate or cholesterol is critical for neurite outgrowth and/or maintenance. Loss of neurites is an early manifestation of various neurodegenerative disorders, and dysfunction of isoprenylation might play a role in their pathogenesis.  相似文献   

11.
Statins are a class of drugs widely used for lowering high cholesterol levels through their action on 3-hydroxy-3-methylglutaryl-CoA reductase, a key enzyme in the synthesis of cholesterol. We studied the effects of two major statins, simvastatin and atorvastatin, on five Candida species and Aspergillus fumigatus. The statins strongly inhibited the growth of all species, except Candida krusei. Supplementation of Candida albicans and A. fumigatus with ergosterol or cholesterol in aerobic culture led to substantial recovery from the inhibition by statins, suggesting specificity of statins for the mevalonate synthesis pathway. Our findings suggest that the statins could have utility as antifungal agents and that fungal colonization could be affected in those on statin therapy.  相似文献   

12.
The effect of compactin on hormonally induced lipogenesis and protein synthesis was studied in vitro in explants of mammary gland from mid-pregnant rabbits. Compactin blocks mevalonate synthesis by the specific inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase, and in this system, culture with 10 microM compactin for 24, 48, and 72 h inhibited incorporation of [1-14C]acetate (but not [2-14C]mevalonate) into sterol by 98, 95, and 86%, respectively. Removal of compactin prior to assay rapidly reversed this effect and was associated with increased tissue 3-hydroxy-3-methylglutaryl-CoA reductase activity. Fatty acid synthesis (measured by incorporation of [1-14C]acetate or [4,5-3H]leucine) and protein synthesis (measured by incorporation of [4,5-3H]leucine) were both inhibited by around 50% after culture with compactin. This inhibition was not rapidly reversed by removal of compactin prior to assay, but it was prevented by inclusion of 1 mM mevalonolactone in the culture medium. After removal of compactin and continued culture in its absence for 24 h with hormones, the normal tissue capacity for fatty acid and protein synthesis was restored, indicating no permanent cell damage. The results suggest a specific requirement for mevalonate (or derived products) for the hormonal maintenance of the increased fatty acid and protein synthesis characteristic of the development of the mammary gland.  相似文献   

13.
播娘蒿hmgr基因保守区片段的克隆与分析   总被引:1,自引:0,他引:1  
通过比较6种植物的8条甲羟戊酸途径关键酶3-羟基-3-甲基戊二酰辅酶A还原酶(HMGR)基因同源区域,设计简并引物,利用RT-PCR技术成功地从播娘蒿叶中扩增出458bp的基因片段。通过BlastP比较,所推断的播娘蒿HMGR蛋白序列与拟南芥(NP_177775)、萝卜(CAA48610)、杜仲(AAV54051)、胡黄连(ABC74565)、喜树(AAB69726)、龙胆草(BAE92730)的一致性分别达到98%、96%、88%、89%、86%和87%。通过对蛋白质保守区、特征区以及进化树分析,证实该片段确为hmgr基因片段,该结果为首次报道。  相似文献   

14.
Inflammatory processes and oxidative stress are known to play a key role in the development of cardiovascular complications such as cardiac hypertrophy induced by chronic intermittent hypoxia (CIH), the most characteristic pathophysiological change of obstructive sleep apnea syndrome (OSAS). Current evidence suggests that competitive inhibitors of 3-hydroxy-3-methylglutaryl-CoA coenzyme A reductase, such as atorvastatin, not only reduce blood lipids but also have anti-inflammatory and inhibit oxidative stress benefits. This study examined the protective role of atorvastatin in CIH-induced cardiac hypertrophy. Adult male wistar rats were subjected to 8 h of intermittent hypoxia/day, with/without atorvastatin for 6 weeks. Ventricular remodeling, toll-like receptor 4 (TLR-4), myeloid differentiation primary response protein 88 (MYD88), inflammatory agents and radical oxygen species were determined. As a result, we found that treatment with atorvastatin markedly inhibited the mRNA and protein expressions of TLR4, MYD88 and the downstream inflammatory agents and radical oxygen species. Administration of atorvastatin following CIH significantly ameliorated the myocardial injury, such as cardiac hypertrophy. In conclusion, Pre-CIH atorvastatin administration may attenuate TLR-4/MYD88 mediated inflammatory processes and oxidative stress in the injured rat myocardium, and this may be one mechanism by which atorvastatin ameliorated myocardial injury following CIH.  相似文献   

15.
Atorvastatin is a 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor, and this drug leads to decreased levels of low density lipoprotein (LDL) cholesterol. Lower LDL cholesterol has direct relationship in reducing mortality from coronary heart diseases. Lipitor® (atorvastatin calcium) was the first drug to reach the annual sales of 10 billion dollars in USA and currently is the top selling pharmaceutical product globally. Atorvastatin has a side chain containing two chiral centers as its pharmacophore and it can be synthesized either from chiral pool precursors, by using metal catalysts; or more preferably by the application of free or immobilized enzymes and whole cell biocatalysts for carrying out either asymmetric synthesis or racemic resolution. Biocatalytic synthesis methods for chiral atorvastatin intermediates employ a wide variety of biocatalysts such as alcohol dehydrogenase, 2-deoxy-d-ribose 5-phosphate aldolase, nitrilase, lipase, etc. and each of these biocatalytic processes is discussed in detail in this paper.  相似文献   

16.
Plasticity of vascular smooth muscle cells (VSMCs) plays a central role in the onset and progression of proliferative vascular diseases. In adult tissue, VSMCs exist in a physiological contractile-quiescent phenotype, which is defined by lack of the ability of proliferation and migration, while high expression of contractile marker proteins. After injury to the vessel, VSMC shifts from a contractile phenotype to a pathological synthetic phenotype, associated with increased proliferation, migration and matrix secretion. It has been demonstrated that PDGF-BB is a critical mediator of VSMCs phenotypic switch. Atorvastatin calcium, a selective inhibitor of 3-hydroxy-3-methyl-glutaryl l coenzyme A (HMG-CoA) reductase, exhibits various protective effects against VSMCs. In this study, we investigated the effects of atorvastatin calcium on phenotype modulation of PDGF-BB-induced VSMCs and the related intracellular signal transduction pathways. Treatment of VSMCs with atorvastatin calcium showed dose-dependent inhibition of PDGF-BB-induced proliferation. Atorvastatin calcium co-treatment inhibited the phenotype modulation and cytoskeleton rearrangements and improved the expression of contractile phenotype marker proteins such as α-SM actin, SM22α and calponin in comparison with PDGF-BB alone stimulated VSMCs. Although Akt phosphorylation was strongly elicited by PDGF-BB, Akt activation was attenuated when PDGF-BB was co-administrated with atorvastatin calcium. In conclusion, atorvastatin calcium inhibits phenotype modulation of PDGF-BB-induced VSMCs and activation of the Akt signaling pathway, indicating that Akt might play a vital role in the modulation of phenotype.  相似文献   

17.
The crystalloid endoplasmic reticulum (ER) of UT-1 cells is a specialized smooth ER that houses 3-hydroxy-3-methylglutaryl-CoA reductase, a membrane protein that regulates endogenous cholesterol synthesis. The biogenesis of this ER is coupled to the over production of 3-hydroxy-3-methylglutaryl-CoA reductase. To understand better this membrane system and the relationship between the synthesis of a membrane protein and the formation of membrane, we have purified the crystalloid ER. Purified crystalloid ER did not contain significant amounts of membrane derived from the Golgi apparatus, mitochondria, or plasma membrane. Approximately 24% of the protein in this organelle corresponded to 3-hydroxy-3-methylglutaryl-CoA reductase; however, at least eight other proteins were detected by gel electrophoresis. One of these proteins (Mr 73,000) was as abundant as reductase. These results suggest that the biogenesis of this ER involves the coordinate synthesis of multiple membrane and content proteins.  相似文献   

18.
Proprotein convertase subtilisin-kexin-9 (PCSK9) inhibition markedly augments the LDL lowering action of statins. The combination is being evaluated for long-term effects on atherosclerotic disease outcomes. However, effects of combined treatment on hepatic cholesterol and bile acid metabolism have not yet been reported. To study this, PCSK9-Y119X mutant (knockout) and wild-type mice were treated with or without atorvastatin for 12 weeks. Atorvastatin progressively lowered plasma LDL in each group, but no differences in liver cholesterol, cholesterol ester, or total bile acid concentrations, or in plasma total bile acid levels were seen. In contrast, atorvastatin increased fecal total bile acids (∼2-fold, P < 0.01) and cholesterol concentrations (∼3-fold, P < 0.01) versus controls for both PCSK9-Y119X and wild-type mice. All 14 individual bile acids resolved by LC-MS, including primary, secondary, and conjugated species, reflected similar increases. Expression of key liver bile acid synthesis genes CYP7A1 and CYP8B1 were ∼2.5-fold higher with atorvastatin in both strains, but mRNA for liver bile acid export and reuptake transporters and conjugating enzymes were not unaffected. The data suggest that hepatocyte cholesterol and bile acid homeostasis is maintained with combined PCSK9 and HMG-CoA reductase inhibition through efficient liver enzymatic conversion of LDL-derived cholesterol into bile acids and excretion of both, with undisturbed enterohepatic recycling.  相似文献   

19.
Abstract: Following a nerve crush, cholesterol from degenerating myelin is retained within the nerve and reutilized for new myelin synthesis during nerve regeneration, apparently via a lipoprotein-mediated process. Because at least some serum components have access to the endoneurium of injured nerve, it has been suggested that serum lipoproteins are also significant contributors of cholesterol to Schwann cells during nerve regeneration. To test this hypothesis, serum cholesterol levels were reduced by >90% with 4-aminopyrazolopyrimidine, followed by measurement of the activity of the key regulatory enzyme in cholesterol synthesis, 3-hydroxy-3-methylglutaryl-CoA reductase. Treatment with 4-aminopyrazolopyrimidine caused a sevenfold increase in 3-hydroxy-3-methylglutaryl-CoA reductase activity in kidney but had no effect on the activity of this enzyme in either intact or regenerating sciatic nerve. These data indicate that serum-derived cholesterol is neither necessary for nor contributes significantly to myelin synthesis in regenerating nerve.  相似文献   

20.
Prostate cancer has become a global health concern and is one of the leading causes of cancer death of men after lung and gastric cancers. It has been suggested that the 3-hydroxy-3-methyl-glutarylcoenzyme-CoA (HMG-CoA) reductase inhibitor atorvastatin shows anticancer activity in prostate cancer cell lines. To this end, we analyzed the influence of atorvastatin on the cell adhesion and differentiation of CD133+CD44+ cells derived from prostate cancer biopsies and peripheral blood. CD133+CD44+ cells were treated with atorvastatin (16–64 μM) for different time periods. Cell adhesion to endothelial cell monolayers and differentiation into prostate cancer cells were evaluated. α1, β1 and α2β1 integrins adhesion receptors and the downstream target of atorvastatin Rho-dependent kinase (ROCK) and focal adhesion kinase (FAK) were analyzed by Western blot. Further blocking studies with the ROCK inhibitor H1152, anti-FAK antibody and anti-integrin α1 and β1 antibodies were carried out. Atorvastatin treatment inhibited dose-dependently cell attachment to endothelium and differentiation. The inhibitory effect of atorvastatin on cell adhesion was associated with decreased expression of integrins α1 and β1 and phosphorylated MYPT1 and FAK. Furthermore, atorvastatin strongly reduced ROCK1 and FAK mediated differentiation of CD133+CD44+ cells, which was confirmed by antibody treatment. Atorvastatin modified the expression of cell adhesion molecules and differentiation markers. These beneficial effects of atorvastatin may be mediated by ROCK and FAK signaling pathway. The data presented may point to novel treatment options for prostate cancer.  相似文献   

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