PMCC PMCC

Search tips
Search criteria

Advanced
Results 1-25 (1295573)

Clipboard (0)
None

Related Articles

1.  Statins impair glucose uptake in human cells 
Objective
Considering the increasing number of clinical observations indicating hyperglycemic effects of statins, this study was designed to measure the influence of statins on the uptake of glucose analogs by human cells derived from liver, adipose tissue, and skeletal muscle.
Design
Flow cytometry and scintillation counting were used to measure the uptake of fluorescently labeled or tritiated glucose analogs by differentiated visceral preadipocytes, skeletal muscle cells, skeletal muscle myoblasts, and contact-inhibited human hepatocellular carcinoma cells. A bioinformatics approach was used to predict the structure of human glucose transporter 1 (GLUT1) and to identify the presence of putative cholesterol-binding (cholesterol recognition/interaction amino acid consensus (CRAC)) motifs within this transporter. Mutagenesis of CRAC motifs in SLC2A1 gene and limited proteolysis of membrane GLUT1 were used to determine the molecular effects of statins.
Results
Statins significantly inhibit the uptake of glucose analogs in all cell types. Similar effects are induced by methyl-β-cyclodextrin, which removes membrane cholesterol. Statin effects can be rescued by addition of mevalonic acid, or supplementation with exogenous cholesterol. Limited proteolysis of GLUT1 and mutagenesis of CRAC motifs revealed that statins induce conformational changes in GLUTs.
Conclusions
Statins impair glucose uptake by cells involved in regulation of glucose homeostasis by inducing cholesterol-dependent conformational changes in GLUTs. This molecular mechanism might explain hyperglycemic effects of statins observed in clinical trials.
doi:10.1136/bmjdrc-2014-000017
PMCID: PMC4212557  PMID: 25452863
Glucose Uptake; GLUT1; Pharmacological Therapy
2.  Simvastatin Enhances Protection against Listeria monocytogenes Infection in Mice by Counteracting Listeria-Induced Phagosomal Escape 
PLoS ONE  2013;8(9):e75490.
Statins are well-known cholesterol lowering drugs targeting HMG-CoA-reductase, reducing the risk of coronary disorders and hypercholesterolemia. Statins are also involved in immunomodulation, which might influence the outcome of bacterial infection. Hence, a possible effect of statin treatment on Listeriosis was explored in mice. Statin treatment prior to subsequent L. monocytogenes infection strikingly reduced bacterial burden in liver and spleen (up to 100-fold) and reduced histopathological lesions. Statin-treatment in infected macrophages resulted in increased IL-12p40 and TNF-α and up to 4-fold reduced bacterial burden within 6 hours post infection, demonstrating a direct effect of statins on limiting bacterial growth in macrophages. Bacterial uptake was normal investigated in microbeads and GFP-expressing Listeria experiments by confocal microscopy. However, intracellular membrane-bound cholesterol level was decreased, as analyzed by cholesterol-dependent filipin staining and cellular lipid extraction. Mevalonate supplementation restored statin-inhibited cholesterol biosynthesis and reverted bacterial growth in Listeria monocytogenes but not in listeriolysin O (LLO)-deficient Listeria. Together, these results suggest that statin pretreatment increases protection against L. monocytogenes infection by reducing membrane cholesterol in macrophages and thereby preventing effectivity of the cholesterol-dependent LLO-mediated phagosomal escape of bacteria.
doi:10.1371/journal.pone.0075490
PMCID: PMC3782446  PMID: 24086542
3.  HMG-CoA reductase inhibitors induce apoptosis of lymphoma cells by promoting ROS generation and regulating Akt, Erk and p38 signals via suppression of mevalonate pathway 
Cell Death & Disease  2013;4(2):e518-.
Statins, the inhibitors of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, are widely used cholesterol-lowering drugs. Convincing evidence indicates that statins stimulate apoptotic cell death in several types of proliferating tumor cells in a cholesterol-lowering-independent manner. The objective here was to elucidate the molecular mechanism by which statins induce lymphoma cells death. Statins (atorvastatin, fluvastatin and simvastatin) treatment enhanced the DNA fragmentation and the activation of proapoptotic members such as caspase-3, PARP and Bax, but suppressed the activation of anti-apoptotic molecule Bcl-2 in lymphoma cells including A20 and EL4 cells, which was accompanied by inhibition of cell survival. Both increase in levels of reactive oxygen species (ROS) and activation of p38 MAPK and decrease in mitochondrial membrane potential and activation of Akt and Erk pathways were observed in statin-treated lymphoma cells. Statin-induced cytotoxic effects, DNA fragmentation and changes of activation of caspase-3, Akt, Erk and p38 were blocked by antioxidant (N-acetylcysteine) and metabolic products of the HMG-CoA reductase reaction, such as mevalonate, farnesyl pyrophosphate (FPP) and geranylgeranyl pyrophosphate (GGPP). These results suggests that HMG-CoA reductase inhibitors induce lymphoma cells apoptosis by increasing intracellular ROS generation and p38 activation and suppressing activation of Akt and Erk pathways, through inhibition of metabolic products of the HMG-CoA reductase reaction including mevalonate, FPP and GGPP.
doi:10.1038/cddis.2013.44
PMCID: PMC3734846  PMID: 23449454
statins; lymphoma cells; apoptosis; mevalonate pathway
4.  Statins Impair Antitumor Effects of Rituximab by Inducing Conformational Changes of CD20 
PLoS Medicine  2008;5(3):e64.
Background
Rituximab is used in the treatment of CD20+ B cell lymphomas and other B cell lymphoproliferative disorders. Its clinical efficacy might be further improved by combinations with other drugs such as statins that inhibit cholesterol synthesis and show promising antilymphoma effects. The objective of this study was to evaluate the influence of statins on rituximab-induced killing of B cell lymphomas.
Methods and Findings
Complement-dependent cytotoxicity (CDC) was assessed by MTT and Alamar blue assays as well as trypan blue staining, and antibody-dependent cellular cytotoxicity (ADCC) was assessed by a 51Cr release assay. Statins were found to significantly decrease rituximab-mediated CDC and ADCC of B cell lymphoma cells. Incubation of B cell lymphoma cells with statins decreased CD20 immunostaining in flow cytometry studies but did not affect total cellular levels of CD20 as measured with RT-PCR and Western blotting. Similar effects are exerted by other cholesterol-depleting agents (methyl-β-cyclodextrin and berberine), but not filipin III, indicating that the presence of plasma membrane cholesterol and not lipid rafts is required for rituximab-mediated CDC. Immunofluorescence microscopy using double staining with monoclonal antibodies (mAbs) directed against a conformational epitope and a linear cytoplasmic epitope revealed that CD20 is present in the plasma membrane in comparable amounts in control and statin-treated cells. Atomic force microscopy and limited proteolysis indicated that statins, through cholesterol depletion, induce conformational changes in CD20 that result in impaired binding of anti-CD20 mAb. An in vivo reduction of cholesterol induced by short-term treatment of five patients with hypercholesterolemia with atorvastatin resulted in reduced anti-CD20 binding to freshly isolated B cells.
Conclusions
Statins were shown to interfere with both detection of CD20 and antilymphoma activity of rituximab. These studies have significant clinical implications, as impaired binding of mAbs to conformational epitopes of CD20 elicited by statins could delay diagnosis, postpone effective treatment, or impair anti-lymphoma activity of rituximab.
Jakub Golab and colleagues found that statins significantly decrease rituximab-mediated complement-dependent cytotoxicity and antibody-dependent cellular cytotoxicity against B cell lymphoma cells.
Editors' Summary
Background.
Lymphomas are common cancers of the lymphatic system, the tissues and organs that produce and store the white blood cells (lymphocytes) that fight infections. In healthy people, the cells in the lymph nodes (collections of lymphocytes in the armpit, groin, and neck) and other lymphatic organs divide to form new cells only when the body needs them. Lymphomas form when a T or B lymphocyte starts to divide uncontrollably. The first sign of lymphoma is often a painless swelling in the armpit, groin, or neck caused by lymphocyte overgrowth in a lymph node. Eventually, the abnormal (malignant) lymphocytes, which provide no protection against infectious diseases, spread throughout the body. Treatments for lymphoma include chemotherapy (drugs that kill rapidly dividing cells) and radiotherapy. In addition, a drug called rituximab was recently developed for the treatment of some types of B cell lymphoma. Rituximab is a monoclonal antibody, a laboratory-produced protein. It binds to a protein called CD20 that is present on the surface of both normal and malignant B lymphocytes and induces cell killing through processes called “complement-dependent cytotoxity” (CDC) and “antibody-dependent cellular cytotoxity” (ADCC).
Why Was This Study Done?
Although rituximab lengthens the lives of patients with some types of B cell lymphoma, it is not a cure—the lymphoma usually recurs. Researchers are trying to increase the effectiveness of rituximab by combining it with other anticancer agents. One group of drugs that might be combined with rituximab is the “statins,” drugs that reduce the risk of heart disease by lowering the level of cholesterol (a type of fat) in the blood. In laboratory experiments, statins kill some cancer cells, in part by altering the fat composition of their outer (plasma) membrane. In addition, some population-based studies suggest that statin treatment might slightly decrease the risk of developing some kinds of cancer, including lymphoma. Statins are already undergoing clinical evaluation in combination with chemotherapy for the treatment of lymphoma, but in this study, the researchers investigate the influence of statins on rituximab-induced killing of B cell lymphomas.
What Did the Researchers Do and Find?
When the researchers tested the ability of rituximab and statin combinations to kill B cell lymphoma cells growing in dishes, they found that statins decreased rituximab-dependent CDC and ADCC of these cells. Statin treatment, they report, did not alter the total amount of CD20 made by the lymphoma cells or the amount of CD20 in their plasma membranes, but it did reduce the binding of another anti-CDC20 monoclonal antibody to the cells. Because both this antibody and rituximab bind to a specific three-dimensional structure in CD20 (a “conformational epitope”), the researchers hypothesized that statins might alter rituximab-induced killing by affecting the shape of the CD20 molecule on the lymphoma cell surface. To test this idea, they used two techniques—atomic force microscopy and limited proteolysis. The data obtained using both approaches confirmed that statins induce shape changes in CD20. Finally, the researchers took B cells from five patients who had taken statins for a short time and showed that this treatment had reduced the amount of anti-CD20 monoclonal antibody able to bind to these cells.
What Do These Findings Mean?
These findings indicate that statins change the shape of the CD20 molecules on the surface of normal and malignant B lymphocytes, probably by changing the amount of cholesterol in the cell membrane. This effect of statins has several clinical implications, which means that cancer specialists should check whether patients with known or suspected B cell lymphoma are taking statins to treat high cholesterol. First, the impaired binding of monoclonal antibodies to conformational epitopes of CD20 in patients being treated with statins might delay the diagnosis of B cell lymphomas (CD20 binding to lymphocytes is used during the diagnosis of lymphomas). Second, some patients with B cell lymphoma may receive an incorrect diagnosis and may not be offered rituximab. Finally, because statins impair the anti-lymphoma activity of rituximab, a possibility that needs to be investigated in clinical studies, cancer specialists should check that patients with B cell lymphoma are not taking statins before prescribing rituximab.
Additional Information.
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.0050064.
The MedlinePlus has an encyclopedia page on lymphoma and a list of links to other sources of information on lymphoma (in English and Spanish)
The US National Cancer Institute provides information about lymphoma and about statins and cancer prevention (in English and Spanish)
The UK charity Cancerbackup provides information for patients and caregivers on different types of B-cell lymphoma and on rituximab
The US Leukemia and Lymphoma Society also provides information for patients and caregivers about lymphoma
doi:10.1371/journal.pmed.0050064
PMCID: PMC2270297  PMID: 18366248
5.  RHOA Is a Modulator of the Cholesterol-Lowering Effects of Statin 
PLoS Genetics  2012;8(11):e1003058.
Although statin drugs are generally efficacious for lowering plasma LDL-cholesterol levels, there is considerable variability in response. To identify candidate genes that may contribute to this variation, we used an unbiased genome-wide filter approach that was applied to 10,149 genes expressed in immortalized lymphoblastoid cell lines (LCLs) derived from 480 participants of the Cholesterol and Pharmacogenomics (CAP) clinical trial of simvastatin. The criteria for identification of candidates included genes whose statin-induced changes in expression were correlated with change in expression of HMGCR, a key regulator of cellular cholesterol metabolism and the target of statin inhibition. This analysis yielded 45 genes, from which RHOA was selected for follow-up because it has been found to participate in mediating the pleiotropic but not the lipid-lowering effects of statin treatment. RHOA knock-down in hepatoma cell lines reduced HMGCR, LDLR, and SREBF2 mRNA expression and increased intracellular cholesterol ester content as well as apolipoprotein B (APOB) concentrations in the conditioned media. Furthermore, inter-individual variation in statin-induced RHOA mRNA expression measured in vitro in CAP LCLs was correlated with the changes in plasma total cholesterol, LDL-cholesterol, and APOB induced by simvastatin treatment (40 mg/d for 6 wk) of the individuals from whom these cell lines were derived. Moreover, the minor allele of rs11716445, a SNP located in a novel cryptic RHOA exon, dramatically increased inclusion of the exon in RHOA transcripts during splicing and was associated with a smaller LDL-cholesterol reduction in response to statin treatment in 1,886 participants from the CAP and Pravastatin Inflamation and CRP Evaluation (PRINCE; pravastatin 40 mg/d) statin clinical trials. Thus, an unbiased filter approach based on transcriptome-wide profiling identified RHOA as a gene contributing to variation in LDL-cholesterol response to statin, illustrating the power of this approach for identifying candidate genes involved in drug response phenotypes.
Author Summary
Statins, or HMG CoA reductase inhibitors, are widely used to lower plasma LDL-cholesterol levels as a means of reducing risk for cardiovascular disease. We performed an unbiased genome-wide survey to identify novel candidate genes that may be involved in statin response using genome-wide mRNA expression analysis in a sequential filtering strategy to identify those most likely to be relevant to cholesterol metabolism based on their gene expression characteristics. Among these, RHOA was selected for further functional study. A role for this gene in the maintenance of intracellular cholesterol homeostasis was confirmed by knock-down in hepatoma cell lines. In addition, statin-induced RHOA transcript levels measured in a panel of lymphoblastoid cell lines was correlated with statin-induced change in plasma LDL-cholesterol measured in individuals from whom the cell lines were derived. Lastly, a cis-acting splicing QTL associated with expression of a rare cryptic RHOA exon was also associated with statin-induced changes in plasma LDLC levels. This result exemplifies the power of applying biological information of well understood molecular pathways with genome-wide expression data for the identification of candidate genes that influence drug response.
doi:10.1371/journal.pgen.1003058
PMCID: PMC3499361  PMID: 23166513
6.  Statin-dependent activation of protein kinase C delta (PKCδ) in APL cells and induction of leukemic cell differentiation 
Leukemia & lymphoma  2012;53(9):1779-1784.
Statins are HMG-CoA reductase inhibitors, which block the conversion of HMG-CoA to mevalonate and have potent cholesterol lowering properties. Beyond their importance in generation of lipid lowering effects, the regulatory effects of statins on the mevalonate pathway have significant impact on multiple other cellular functions. There is now extensive evidence that statins have anti-inflammatory and anti-neoplastic properties, but the precise mechanisms by which such responses are generated are not well understood. In the present study we demonstrate that statins engage a member of the PKC family of proteins, PKCδ, in acute promyelocytic leukemia (APL) cells. Our studies show that atorvastatin and fluvastatin induce proteolytic activation of PKCδ in the APL NB4 cell line which expresses the t(15;17) translocation. Such engagement of PKCδ results in induction of its kinase domain and downstream regulation of pathways important for statin-dependent leukemia cell differentiation. Our studies show that the function of PKCδ is essential for statin-induced leukemic cell differentiation, as demonstrated by studies involving selective targeting of PKCδ using siRNAs. We also demonstrate that the potent enhancing effects of statins on ATRA-induced gene expression for CCL3 and CCL4 requires the function of PKCδ, suggesting a mechanism by which statins may promote ATRA-induced antileukemic responses. Altogether, our data establish a novel function for PKCδ as a mediator of statin-induced differentiation of APL cells and antileukemic effects.
doi:10.3109/10428194.2012.668287
PMCID: PMC3616499  PMID: 22356114
7.  Lipophilic but not hydrophilic statins selectively induce cell death in gynaecological cancers expressing high levels of HMGCoA reductase 
Abstract
Recent reports have suggested that statins induce cell death in certain epithelial cancers and that patients taking statins to reduce cholesterol levels possess lower cancer incidence. However, little is known about the mechanisms of action of different statins or the effects of these statins in gynaecological malignancies. The apoptotic potential of two lipophilic statins (lovastatin and simvastatin) and one hydrophilic statin (pravastatin) was assessed in cancer cell lines (ovarian, endometrial and cervical) and primary cultured cancerous and normal tissues. Cell viability was studied by MTS assays and apoptosis was confirmed by Western blotting of PARP and flow cytometry. The expressions of key apoptotic cascade proteins were analysed. Our results demonstrate that both lovastatin and simvastatin, but not pravastatin, selectively induced cell death in dose- and time-dependent manner in ovarian, endometrial and cervical cancers. Little or no toxicity was observed with any statin on normal cells. Lipophilic statins induced activation of caspase-8 and -9; BID cleavage, cytochrome C release and PARP cleavage. Statin-sensitive cancers expressed high levels of HMG-CoA reductase compared with resistant cultures. The effect of lipophilic statins was dependent on inhibition of enzymatic activity of HMG-CoA reductase since mevalonate pre-incubation almost completely abrogated the apoptotic effect. Moreover, the apoptotic effect involved the inhibition of synthesis of geranylgeranyl pyrophosphate rather than farnesyl pyrophosphate. In conclusion, lipophilic but not hydrophilic statins induce cell death through activation of extrinsic and intrinsic apoptotic cascades in cancerous cells from the human female genital tract, which express high levels of HMG-CoA reductase. These results promote further investigation in the use of lipophilic statins as anticancer agents in gynaecological malignancies.
doi:10.1111/j.1582-4934.2009.00771.x
PMCID: PMC3822754  PMID: 19432822
statins; gynaecological cancers; apoptosis; therapy
8.  Dose-dependent Effect of Statin Therapy on Circulating CXCL12 Levels in Patients with Hyperlipidemia 
Background
HMG-CoA reductase inhibitors (statins) have pleiotropic effects that are independent of cholesterol-lowering, including a dose-dependent effect on angiogenesis. Angiogenesis plays a critical role both in vascularization of the chronically ischemic myocardium and in stabilization of atherosclerotic plaques. Chemokines, a family of structurally-related cytokine molecules, exert diverse biological functions including control of angiogenesis. The effect of statin therapy on angiogenic and angiostatic chemokines has not been evaluated extensively. We sought to test the hypothesis that, in subjects with hyperlipidemia, statin therapy influences plasma levels of angiogenic and angiostatic chemokines in a dose-dependent manner.
Methods
We prospectively collected demographic, angiographic and laboratory data from subjects with a history of hyperlipidemia who were either untreated or on statin therapy. A peripheral blood sample was obtained for measurement of plasma angiogenic and angiostatic chemokines. Multivariable analysis using logistic regression was performed adjusting for the following variables: age, gender, prior myocardial infarction, and chronic administration of aspirin, clopidogrel, insulin, oral hypoglycemic agents, beta-blockers and calcium channel blockers.
Results
168 patients on statin therapy (48 on low-dose, defined as <10mg atorvastatin-equivalent, and 120 on high-dose, defined as ≥10mg atorvastatin-equivalent dose) and 11 subjects from the same database who had a history of hyperlipidemia but who were not on statins were enrolled. There were no significant differences in baseline demographics, co-morbidities, lipid panels, other medications, or angiographic data between the groups. The angiogenic chemokines CXCL1 and CXCL12 levels were significantly different across the groups. Median levels of CXCL1 were highest in subjects not on statin therapy. Compared to subjects either not on statin therapy or on low-dose statins, those taking high-dose statins had lower median values of CXCL12 (2316 [2255–11071], vs 2362 [2016–10622], vs 2189 [1968–2705] pg/mL, p=0.042). On multivariate analysis, CXCL12 remained the only factor that was strongly and inversely associated with statin dose at the 95% level (p=0.011).
Conclusions
Compared to no therapy or low-dose statin therapy, treatment with high-doses of HMG-CoA reductase inhibitors is associated with decreased circulating CXCL12 levels in subjects with hyperlipidemia, and CXCL12 is strongly and inversely associated with statin dose. Additional studies are needed to confirm this finding in other cohorts and to determine if high-dose statins affect angiogenesis in patients.
doi:10.1186/2001-1326-1-23
PMCID: PMC3560987  PMID: 23369699
CXCL12; Chemokine; Statin
9.  The effects of statins on the mevalonic acid pathway in recombinant yeast strains expressing human HMG-CoA reductase 
BMC Biotechnology  2013;13:68.
Background
The yeast Saccharomyces cerevisiae can be a useful model for studying cellular mechanisms related to sterol synthesis in humans due to the high similarity of the mevalonate pathway between these organisms. This metabolic pathway plays a key role in multiple cellular processes by synthesizing sterol and nonsterol isoprenoids. Statins are well-known inhibitors of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR), the key enzyme of the cholesterol synthesis pathway. However, the effects of statins extend beyond their cholesterol-lowering action, since inhibition of HMGR decreases the synthesis of all products downstream in the mevalonate pathway. Using transgenic yeast expressing human HMGR or either yeast HMGR isoenzyme we studied the effects of simvastatin, atorvastatin, fluvastatin and rosuvastatin on the cell metabolism.
Results
Statins decreased sterol pools, prominently reducing sterol precursors content while only moderately lowering ergosterol level. Expression of genes encoding enzymes involved in sterol biosynthesis was induced, while genes from nonsterol isoprenoid pathways, such as coenzyme Q and dolichol biosynthesis or protein prenylation, were diversely affected by statin treatment. Statins increased the level of human HMGR protein substantially and only slightly affected the levels of Rer2 and Coq3 proteins involved in non-sterol isoprenoid biosynthesis.
Conclusion
Statins influence the sterol pool, gene expression and protein levels of enzymes from the sterol and nonsterol isoprenoid biosynthesis branches and this effect depends on the type of statin administered. Our model system is a cheap and convenient tool for characterizing individual statins or screening for novel ones, and could also be helpful in individualized selection of the most efficient HMGR inhibitors leading to the best response and minimizing serious side effects.
doi:10.1186/1472-6750-13-68
PMCID: PMC3765880  PMID: 24128347
HMG-CoA reductase; Statins; Yeast expression system; Heterologous proteins; Mevalonate pathway
10.  The Impact of Exercise on Statin-Associated Skeletal Muscle Myopathy 
PLoS ONE  2016;11(12):e0168065.
HMG-CoA reductase inhibitors (statins) are the most effective pharmacological means of reducing cardiovascular disease risk. The most common side effect of statin use is skeletal muscle myopathy, which may be exacerbated by exercise. Hypercholesterolemia and training status are factors that are rarely considered in the progression of myopathy. The purpose of this study was to determine the extent to which acute and chronic exercise can influence statin-induced myopathy in hypercholesterolemic (ApoE-/-) mice. Mice either received daily injections of saline or simvastatin (20 mg/kg) while: 1) remaining sedentary (Sed), 2) engaging in daily exercise for two weeks (novel, Nov), or 3) engaging in daily exercise for two weeks after a brief period of training (accustomed, Acct) (2x3 design, n = 60). Cholesterol, activity, strength, and indices of myofiber damage and atrophy were assessed. Running wheel activity declined in both exercise groups receiving statins (statin x time interaction, p<0.05). Cholesterol, grip strength, and maximal isometric force were significantly lower in all groups following statin treatment (statin main effect, p<0.05). Mitochondrial content and myofiber size were increased and 4-HNE was decreased by exercise (statin x exercise interaction, p<0.05), and these beneficial effects were abrogated by statin treatment. Exercise (Acct and Nov) increased atrogin-1 mRNA in combination with statin treatment, yet enhanced fiber damage or atrophy was not observed. The results from this study suggest that exercise (Nov, Acct) does not exacerbate statin-induced myopathy in ApoE-/- mice, yet statin treatment reduces activity in a manner that prevents muscle from mounting a beneficial adaptive response to training.
doi:10.1371/journal.pone.0168065
PMCID: PMC5148116  PMID: 27936249
11.  Evaluation of the effect of genetic variation on the relationship between statins, cardiovascular disease and cancer 
Statins are a class of medications that are competitive inhibitors of Hydroxy Methyl Glutaryl Co-enzyme A (HMG-CoA) reductase which is the rate-limiting enzyme in the cholesterol bio-synthesis pathway. As a result, statins lower total cholesterol and low density lipoprotein (LDL) cholesterol thus impacting cardiovascular mortality. The downstream effects of statins are not limited to inhibition of cholesterol synthesis alone. Statins have anti-inflammatory effects thought to be important in the setting of acute myocardial infarction which also may be a mechanism involved in anti-carcinogenic properties of statins. Furthermore, statin inhibition of the mevalonate pathway may impact Ras and RhoGTPases that are important in cell proliferation, migration and apoptosis. These alterations may also play a role in the anti-cancer effect of statins. In this article we will review the literature on how genetic variation modifies the effect of statins on the risk of cardiovascular disease and how genetic variation may impact the relationship between statins and the risk of a number of different cancers.
PMCID: PMC3852638  PMID: 24319534
Statins; blood lipids; cancer risk; cardiovascular disease; genetic variation
12.  Chronic HMGCR/HMG-CoA reductase inhibitor treatment contributes to dysglycemia by upregulating hepatic gluconeogenesis through autophagy induction 
Autophagy  2015;11(11):2089-2101.
Statins (HMGCR/HMG-CoA reductase [3-hydroxy-3-methylglutaryl-CoA reductase] inhibitors) are widely used to lower blood cholesterol levels but have been shown to increase the risk of type 2 diabetes mellitus. However, the molecular mechanism underlying diabetogenic effects remains to be elucidated. Here we show that statins significantly increase the expression of key gluconeogenic enzymes (such as G6PC [glucose-6-phosphatase] and PCK1 (phosphoenolpyruvate carboxykinase 1 [soluble]) in vitro and in vivo and promote hepatic glucose output. Statin treatment activates autophagic flux in HepG2 cells. Acute suppression of autophagy with lysosome inhibitors in statin treated HepG2 cells reduced gluconeogenic enzymes expression and glucose output. Importantly, the ability of statins to increase gluconeogenesis was impaired when ATG7 was deficient and BECN1 was absent, suggesting that autophagy plays a critical role in the diabetogenic effects of statins. Moreover autophagic vacuoles and gluconeogenic genes expression in the liver of diet-induced obese mice were increased by statins, ultimately leading to elevated hepatic glucose production, hyperglycemia, and insulin resistance. Together, these data demonstrate that chronic statin therapy results in insulin resistance through the activation of hepatic gluconeogenesis, which is tightly coupled to hepatic autophagy. These data further contribute to a better understanding of the diabetogenic effects of stains in the context of insulin resistance.
doi:10.1080/15548627.2015.1091139
PMCID: PMC4824590  PMID: 26389569
autophagy; diabetes; gluconeogenesis; HMG-CoA reductase inhibitor; statin
13.  Rosuvastatin Treatment Affects Both Basal and Glucose-Induced Insulin Secretion in INS-1 832/13 Cells 
PLoS ONE  2016;11(3):e0151592.
Rosuvastatin is a member of the statin family. Like the other statins it is prescribed to lower cholesterol levels and thereby reduce the risk of cardiovascular events. Rosuvastatin lowers the cholesterol levels by inhibiting the key enzyme 3-hydroxy-3-methyl-glutaryl-CoA reductase (HMG-CoA reductase) in the cholesterol producing mevalonate pathway. It has been recognized that apart from their beneficial lipid lowering effects, statins also exhibit diabetogenic properties. The molecular mechanisms behind these remain unresolved. To investigate the effects of rosuvastatin on insulin secretion, we treated INS-1 832/13 cells with varying doses (20 nM to 20 μM) of rosuvastatin for 48 h. At concentrations of 2 μM and above basal insulin secretion was significantly increased. Using diazoxide we could determine that rosuvastatin did not increase basal insulin secretion by corrupting the KATP channels. Glucose-induced insulin secretion on the other hand seemed to be affected differently at different rosuvastatin concentrations. Rosuvastatin treatment (20 μM) for 24–48 h inhibited voltage-gated Ca2+ channels, which lead to reduced depolarization-induced exocytosis of insulin-containing granules. At lower concentrations of rosuvastatin (≤ 2 μM) the stimulus-secretion coupling pathway was intact downstream of the KATP channels as assessed by the patch clamp technique. However, a reduction in glucose-induced insulin secretion could be observed with rosuvastatin concentrations as low as 200 nM. The inhibitory effects of rosuvastatin on glucose-induced insulin secretion could be reversed with mevalonate, but not squalene, indicating that rosuvastatin affects insulin secretion through its effects on the mevalonate pathway, but not through the reduction of cholesterol biosynthesis. Taken together, these data suggest that rosuvastatin has the potential to increase basal insulin secretion and reduce glucose-induced insulin secretion. The latter is possibly an unavoidable side effect of rosuvastatin treatment as it occurs through the same mechanisms as the lipid-lowering effects of the drug.
doi:10.1371/journal.pone.0151592
PMCID: PMC4795644  PMID: 26986474
14.  Statins impair glucose uptake in tumor cells 
Cancer Biology & Therapy  2013;14(2):92-94.
Statins play a pivotal role in lowering the blood cholesterol level, which is critical for patients with hypercholesterolemia. In addition to its benefits in cardiovascular protection, statins have been found to be useful in several other clinical conditions, including cancer. In a recent report that appeared in Neoplasia, Malenda et al., have demonstrated that statins inhibit glucose uptake in cancer cells. Using multiple statins and glucose analogs (18FDG and 6-NBDG) they showed that inhibition of cholesterol synthesis underlies the blockade of glucose uptake in several cancer cell lines. Further, based on an exploratory clinical study, they also showed that diagnostic PET-CT imaging in patients treated for hypercholesterolemia was affected due to statin-mediated inhibition of glucose uptake. As the finding is based on the data from a single patient (out of four), it seems that (1) the need for a large cohort study and (2) the detailed characterization of the molecular mechanisms underlying such biological effects would be justified.
doi:10.4161/cbt.23290
PMCID: PMC3572005  PMID: 23254955
statins; glucose uptake; FDG; PET imaging; cholesterol; GLUT1; cancer
15.  Statins stimulate arachidonic acid release and prostaglandin I2 production in rat liver cells 
Statins inhibit 3-hydroxy-3-methylglutaryl (HMG-CoA) reductase, the rate limiting step in cholesterol synthesis. They are, therefore, used clinically to lower cholesterol and prevent atherosclerosis. Statins have beneficial effects on multiple organ systems. Some of these effects are found in the absence of significant changes in cholesterol levels. Polyunsaturated fatty acids also inhibit HMG-CoA reductase and have many of the same beneficial effects of statins. Four statins (mevastatin, lovastatin, simvastatin and atorvastatin) have been tested in rat liver cells for their effect on arachidonic acid (AA) release and prostaglandin I2 production induced in the presence of lactacystin and 12-O-tetradecanoylphorbol-13-acetate. Each statin stimulated release of AA and induced prostaglandin I2 production. Mevalonate, the product of HMG-CoA reductase, did not reduce the stimulation observed in the presence of simvastatin indicating that HMG-CoA reductase activity is not involved. In view of the multiple biologic properties of AA, the AA released as a result of the action of the statins may play a role in some of the pharmacological effects attributed to these drugs.
doi:10.1186/1476-511X-2-1
PMCID: PMC153527  PMID: 12689340
16.  Statin-induced inhibition of the Rho-signaling pathway activates PPARα and induces HDL apoA-I 
Journal of Clinical Investigation  2001;107(11):1423-1432.
Statins are inhibitors of the rate-limiting enzyme in cholesterol synthesis, 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase. In addition to reducing LDL cholesterol, statin treatment increases the levels of the antiatherogenic HDL and its major apolipoprotein apoA-I. Here, we investigated the molecular mechanisms of apoA-I regulation by statins. Treatment with statins increased apoA-I mRNA levels in human HepG2 hepatoma cells, and this effect was reversed by the addition of mevalonate, implicating HMG-CoA reductase as the relevant target of these drugs. Pretreatment with Actinomycin D abolished the increase of apoA-I mRNA, indicating that statins act at the transcriptional level. Indeed, statins increased the human apoA-I promoter activity in transfected cells, and we have identified a statin response element that coincides with a PPARα response element known to confer fibrate responsiveness to this gene. The statin effect could be abolished not only by mevalonate, but also by geranylgeranyl pyrophosphate, whereas inhibition of geranylgeranyl transferase activity or treatment with an inhibitor of the Rho GTP-binding protein family increased PPARα activity. Using dominant negative forms of these proteins, we found that Rho A itself mediates this response. Because cotreatment with statins and fibrates activated PPARα in a synergistic manner, these observations provide a molecular basis for combination treatment with statins and fibrates in coronary heart disease.
PMCID: PMC209316  PMID: 11390424
17.  Targeting the Mevalonate Cascade as a New Therapeutic Approach in Heart Disease, Cancer and Pulmonary Disease 
Pharmacology & therapeutics  2014;143(1):87-110.
The cholesterol biosynthesis pathway, also known as the mevalonate (MVA) pathway, is an essential cellular pathway that is involved in diverse cell functions. The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR) is the rate-limiting step in cholesterol biosynthesis and catalyzes the conversion of HMG-CoA to MVA.
Given its role in cholesterol and isoprenoid biosynthesis, the regulation of HMGCR has been intensely investigated. Because all cells require a steady supply of MVA, both the sterol (i.e. cholesterol) and non-sterol (i.e. isoprenoid) products of MVA metabolism exert coordinated feedback regulation on HMGCR through different mechanisms. The proper functioning of HMGCR as the proximal enzyme in the MVA pathway is essential under both normal physiologic conditions and in many diseases given its role in cell cycle pathways and cell proliferation, cholesterol biosynthesis and metabolism, cell cytoskeletal dynamics and stability, cell membrane structure and fluidity, mitochondrial function, proliferation, and cell fate.
The blockbuster statin drugs (‘statins’) directly bind to and inhibit HMGCR, and their use for the past thirty years has revolutionized the treatment of hypercholesterolemia and cardiovascular diseases, in particular coronary heart disease. Initially thought to exert their effects through cholesterol reduction, recent evidence indicates that statins also have pleiotropic immunomodulatory properties independent of cholesterol lowering.
In this review we will focus on the therapeutic applications and mechanisms involved in the MVA cascade including Rho GTPase and Rho kinase (ROCK) signaling, statin inhibition of HMGCR, geranylgeranyltransferase (GGTase) inhibition, and farnesyltransferase (FTase) inhibition in cardiovascular disease, pulmonary diseases (e.g. asthma and chronic obstructive pulmonary disease (COPD), and cancer.
doi:10.1016/j.pharmthera.2014.02.007
PMCID: PMC4005604  PMID: 24582968
Statins; geranylgeranyl transferase inhibitors; farnesy transferase inhibtors; Rho GTPase; asthma; chronic obstructive pulmonary disease; fibrosis; cancer
18.  Personalized Prediction of Lifetime Benefits with Statin Therapy for Asymptomatic Individuals: A Modeling Study 
PLoS Medicine  2012;9(12):e1001361.
In a modeling study conducted by Myriam Hunink and colleagues, a population-based cohort from Rotterdam is used to predict the possible lifetime benefits of statin therapy, on a personalized basis.
Background
Physicians need to inform asymptomatic individuals about personalized outcomes of statin therapy for primary prevention of cardiovascular disease (CVD). However, current prediction models focus on short-term outcomes and ignore the competing risk of death due to other causes. We aimed to predict the potential lifetime benefits with statin therapy, taking into account competing risks.
Methods and Findings
A microsimulation model based on 5-y follow-up data from the Rotterdam Study, a population-based cohort of individuals aged 55 y and older living in the Ommoord district of Rotterdam, the Netherlands, was used to estimate lifetime outcomes with and without statin therapy. The model was validated in-sample using 10-y follow-up data. We used baseline variables and model output to construct (1) a web-based calculator for gains in total and CVD-free life expectancy and (2) color charts for comparing these gains to the Systematic Coronary Risk Evaluation (SCORE) charts. In 2,428 participants (mean age 67.7 y, 35.5% men), statin therapy increased total life expectancy by 0.3 y (SD 0.2) and CVD-free life expectancy by 0.7 y (SD 0.4). Age, sex, smoking, blood pressure, hypertension, lipids, diabetes, glucose, body mass index, waist-to-hip ratio, and creatinine were included in the calculator. Gains in total and CVD-free life expectancy increased with blood pressure, unfavorable lipid levels, and body mass index after multivariable adjustment. Gains decreased considerably with advancing age, while SCORE 10-y CVD mortality risk increased with age. Twenty-five percent of participants with a low SCORE risk achieved equal or larger gains in CVD-free life expectancy than the median gain in participants with a high SCORE risk.
Conclusions
We developed tools to predict personalized increases in total and CVD-free life expectancy with statin therapy. The predicted gains we found are small. If the underlying model is validated in an independent cohort, the tools may be useful in discussing with patients their individual outcomes with statin therapy.
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Cardiovascular disease (CVD) affects the heart and/or the blood vessels and is a major cause of illness and death worldwide. In the US, for example, coronary heart disease—a CVD in which narrowing of the heart's blood vessels by fatty deposits slows the blood supply to the heart and may eventually cause a heart attack—is the leading cause of death, and stroke—a CVD in which the brain's blood supply is interrupted—is the fourth leading cause of death. Established risk factors for CVD include smoking, high blood pressure, obesity, and high blood levels of a fat called low-density lipoprotein (“bad cholesterol”). Because many of these risk factors can be modified by lifestyle changes and by drugs, CVD can be prevented. Thus, physicians can assess a healthy individual's risk of developing CVD using a CVD prediction model (equations that take into account the CVD risk factors to which the individual is exposed) and can then recommend lifestyle changes and medications to reduce that individual's CVD risk.
Why Was This Study Done?
Current guidelines recommend that asymptomatic (healthy) individuals whose likely CVD risk is high should be encouraged to take statins—cholesterol-lowering drugs—as a preventative measure. Statins help to prevent CVD in healthy people with a high predicted risk of CVD, but, like all medicines, they have some unwanted side effects, so it is important that physicians can communicate both the benefits and drawbacks of statins to their patients in a way that allows them to make an informed decision about taking these drugs. Telling a patient that statins will reduce his or her short-term risk of CVD is not always helpful—patients really need to know the potential lifetime benefits of statin therapy. That is, they need to know how much longer they might live if they take statins. Here, the researchers use a mathematical model to predict the personalized lifetime benefits (increased total and CVD-free life expectancy) of statin therapy for individuals without a history of CVD.
What Did the Researchers Do and Find?
The researchers used the Rotterdam Ischemic Heart Disease & Stroke Computer Simulation (RISC) model, which simulates the life courses of individuals through six health states, from well through to CVD or non-CVD death, to estimate lifetime outcomes with and without statin therapy in a population of healthy elderly individuals. They then used these outcomes and information on baseline risk factors to develop a web-based calculator suitable for personalized prediction of the lifetime benefits of statins in routine clinical practice. The model estimated that statin therapy increases average life expectancy in the study population by 0.3 years and average CVD-free life expectancy by 0.7 years. The gains in total and CVD-free life expectancy associated with statin therapy increased with blood pressure, unfavorable cholesterol levels, and body mass index (an indicator of body fat) but decreased with age. Notably, the web-based calculator predicted that some individuals with a low ten-year CVD risk might achieve a similar or larger gain in CVD-free life expectancy with statin therapy than some individuals with a high ten-year risk. So, for example, both a 55-year-old non-smoking woman with a ten-year CVD mortality risk of 2% (a two in a hundred chance of dying of CVD within ten years) and a 65-year-old male smoker with a ten-year CVD mortality risk of 15% might both gain one year of CVD-free life expectancy with statin therapy.
What Do These Findings Mean?
These findings suggest that statin therapy can lead on average to small gains in total life expectancy and slightly larger gains in CVD-free life expectancy among healthy individuals, and show that life expectancy benefits can be predicted using an individual's risk factor profile. The accuracy and generalizability of these findings is limited by the assumptions included in the model (in particular, the model did not allow for the known side effects of statin therapy) and by the data fed into it—importantly, the risk prediction model needs to be validated using an independent dataset. If future research confirms the findings of this study, the researchers' web-based calculator could provide complementary information to the currently recommended ten-year CVD mortality risk assessment. Whether communication of personalized outcomes will ultimately result in better clinical outcomes remains to be seen, however, because patients may be less likely to choose statin therapy when provided with more information about its likely benefits.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001361.
The web-based calculator for personalized prediction of lifetime benefits with statin therapy is available (after agreement to software license)
The American Heart Association provides information about many types of cardiovascular disease for patients, carers, and professionals, including information about drug therapy for cholesterol and a heart attack risk calculator
The UK National Health Service Choices website provides information about cardiovascular disease and about statins
Information is available from the British Heart Foundation on heart disease and keeping the heart healthy; information is also available on statins, including personal stories about deciding to take statins
The US National Heart Lung and Blood Institute provides information on a wide range of cardiovascular diseases
The European Society of Cardiology's cardiovascular disease risk assessment model (SCORE) is available
MedlinePlus provides links to many other sources of information on heart diseases, vascular diseases, stroke, and statins (in English and Spanish)
doi:10.1371/journal.pmed.1001361
PMCID: PMC3531501  PMID: 23300388
19.  HMG CoA reductase inhibitors affect the fibrinolytic system of human vascular cells in vitro: a comparative study using different statins 
British Journal of Pharmacology  2002;135(1):284-292.
The results of several clinical studies investigating the effect of statin therapy on the fibrinolytic system in vivo are inconclusive. We compared the effect of six different statins (atorvastatin, cerivastatin, fluvastatin, lovastatin, pravastatin, simvastatin) on components of the fibrinolytic system expressed by human vascular endothelial cells and smooth muscle cells and by the human hepatoma cell line HepG2.All statins used except pravastatin significantly decreased PAI-1 production in human endothelial and smooth muscle cells. This effect was also seen in the presence of IL-1α and TNF-α. All statins except pravastatin increased t-PA production in human smooth muscle cells. On a molar basis cerivastatin was the most effective HMG CoA reductase inhibitor used. Only simvastatin and lovastatin increased t-PA production in endothelial cells. The effects on the fibrinolytic system were reversed by mevalonate. Statins decreased mRNA levels for PAI-1 in endothelial and smooth muscle cells and increased mRNA levels for t-PA in smooth muscle cells. Statins did not affect PAI-1 expression in HepG2 cells. Cell viability was not influenced by statins in endothelial cells and HepG2 cells whereas in smooth muscle cells a cytotoxic effect was seen at high concentrations.If the effects on the fibrinolytic system of vascular cells in vitro shown in this study are also operative in vivo one could speculate that by increasing t-PA and decreasing PAI-1 at sites of vascular lesions statins might reduce fibrin formation and thrombus development. Such an effect might contribute to the clinically proven benefits of statin therapy.
doi:10.1038/sj.bjp.0704454
PMCID: PMC1573117  PMID: 11786505
Experimental; vasculature; cellular; pathophysiology; atherosclerosis; cytokines; endothelial function; smooth muscle; thrombosis
20.  Simvastatin Inhibits Glucose Metabolism and Legumain Activity in Human Myotubes 
PLoS ONE  2014;9(1):e85721.
Simvastatin, a HMG-CoA reductase inhibitor, is prescribed worldwide to patients with hypercholesterolemia. Although simvastatin is well tolerated, side effects like myotoxicity are reported. The mechanism for statin-induced myotoxicity is still poorly understood. Reports have suggested impaired mitochondrial dysfunction as a contributor to the observed myotoxicity. In this regard, we wanted to study the effects of simvastatin on glucose metabolism and the activity of legumain, a cysteine protease. Legumain, being the only known asparaginyl endopeptidase, has caspase-like properties and is described to be involved in apoptosis. Recent evidences indicate a regulatory role of both glucose and statins on cysteine proteases in monocytes. Satellite cells were isolated from the Musculus obliquus internus abdominis of healthy human donors, proliferated and differentiated into polynuclear myotubes. Simvastatin with or without mevalonolactone, farnesyl pyrophosphate or geranylgeranyl pyrophosphate were introduced on day 5 of differentiation. After 48 h, cells were either harvested for immunoblotting, ELISA, cell viability assay, confocal imaging or enzyme activity analysis, or placed in a fuel handling system with [14C]glucose or [3H]deoxyglucose for uptake and oxidation studies. A dose-dependent decrease in both glucose uptake and oxidation were observed in mature myotubes after exposure to simvastatin in concentrations not influencing cell viability. In addition, simvastatin caused a decrease in maturation and activity of legumain. Dysregulation of glucose metabolism and decreased legumain activity by simvastatin points out new knowledge about the effects of statins on skeletal muscle, and may contribute to the understanding of the myotoxicity observed by statins.
doi:10.1371/journal.pone.0085721
PMCID: PMC3885717  PMID: 24416446
21.  Mechanisms and assessment of statin-related muscular adverse effects 
Statin-associated muscular adverse effects cover a wide range of symptoms, including asymptomatic increase of creatine kinase serum activity and life-threatening rhabdomyolysis. Different underlying pathomechanisms have been proposed. However, a unifying concept of the pathogenesis of statin-related muscular adverse effects has not emerged so far. In this review, we attempt to categorize these mechanisms along three levels. Firstly, among pharmacokinetic factors, it has been shown for some statins that inhibition of cytochrome P450-mediated hepatic biotransformation and hepatic uptake by transporter proteins contribute to an increase of systemic statin concentrations. Secondly, at the myocyte membrane level, cell membrane uptake transporters affect intracellular statin concentrations. Thirdly, at the intracellular level, inhibition of the 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase results in decreased intracellular concentrations of downstream metabolites (e.g. selenoproteins, ubiquinone, cholesterol) and alteration of gene expression (e.g. ryanodine receptor 3, glycine amidinotransferase). We also review current recommendations for prescribers.
doi:10.1111/bcp.12360
PMCID: PMC4243897  PMID: 25069381
adverse effects; efflux transporters; myopathy; organic anion transporters; rhabdomyolysis; statins
22.  Polymorphisms in the Mitochondrial Ribosome Recycling Factor EF-G2mt/MEF2 Compromise Cell Respiratory Function and Increase Atorvastatin Toxicity 
PLoS Genetics  2012;8(6):e1002755.
Mitochondrial translation, essential for synthesis of the electron transport chain complexes in the mitochondria, is governed by nuclear encoded genes. Polymorphisms within these genes are increasingly being implicated in disease and may also trigger adverse drug reactions. Statins, a class of HMG-CoA reductase inhibitors used to treat hypercholesterolemia, are among the most widely prescribed drugs in the world. However, a significant proportion of users suffer side effects of varying severity that commonly affect skeletal muscle. The mitochondria are one of the molecular targets of statins, and these drugs have been known to uncover otherwise silent mitochondrial mutations. Based on yeast genetic studies, we identify the mitochondrial translation factor MEF2 as a mediator of atorvastatin toxicity. The human ortholog of MEF2 is the Elongation Factor Gene (EF-G) 2, which has previously been shown to play a specific role in mitochondrial ribosome recycling. Using small interfering RNA (siRNA) silencing of expression in human cell lines, we demonstrate that the EF-G2mt gene is required for cell growth on galactose medium, signifying an essential role for this gene in aerobic respiration. Furthermore, EF-G2mt silenced cell lines have increased susceptibility to cell death in the presence of atorvastatin. Using yeast as a model, conserved amino acid variants, which arise from non-synonymous single nucleotide polymorphisms (SNPs) in the EF-G2mt gene, were generated in the yeast MEF2 gene. Although these mutations do not produce an obvious growth phenotype, three mutations reveal an atorvastatin-sensitive phenotype and further analysis uncovers a decreased respiratory capacity. These findings constitute the first reported phenotype associated with SNPs in the EF-G2mt gene and implicate the human EF-G2mt gene as a pharmacogenetic candidate gene for statin toxicity in humans.
Author Summary
The mitochondria are responsible for producing the cell's energy. Energy production is the result of carefully orchestrated interactions between proteins encoded by the mitochondrial DNA and by nuclear DNA. Sequence variations in genes encoding these proteins have been shown to cause disease and adverse drug reactions in patients. The cholesterol-lowering drugs statins are one class of drugs that interfere with mitochondrial function. Statins are one of the most prescribed drugs in the western world, but many users suffer side effects, commonly muscle pain. In severe cases this can lead to muscle breakdown and liver failure. In this study, we discover that disruption of a mitochondrial translation gene, EF-G2mt, impedes respiration and increases cell death when exposed to statin. Using the simple unicellular organism yeast as a model, the activity of naturally occurring human EF-G2mt variants is tested. Three of these variants render yeast cells more sensitive to statin. Patients who possess these EF-G2mt variations may be more susceptible to statin side effects. Importantly, the test for statin sensitivity also led to the discovery of mutants that have a reduced energy production capacity. The decreased ability to produce energy is linked to a number of diseases, including myopathies and liver failure.
doi:10.1371/journal.pgen.1002755
PMCID: PMC3375252  PMID: 22719265
23.  Statins Promote the Regression of Atherosclerosis via Activation of the CCR7-Dependent Emigration Pathway in Macrophages 
PLoS ONE  2011;6(12):e28534.
HMG-CoA reductase inhibitors (statins) decrease atherosclerosis by lowering low-density-lipoprotein cholesterol. Statins are also thought to have additional anti-atherogenic properties, yet defining these non-conventional modes of statin action remains incomplete. We have previously developed a novel mouse transplant model of atherosclerosis regression in which aortic segments from diseased donors are placed into normolipidemic recipients. With this model, we demonstrated the rapid loss of CD68+ cells (mainly macrophages) in plaques through the induction of a chemokine receptor CCR7-dependent emigration process. Because the human and mouse CCR7 promoter contain Sterol Response Elements (SREs), we hypothesized that Sterol Regulatory Element Binding Proteins (SREBPs) are involved in increasing CCR7 expression and through this mechanism, statins would promote CD68+ cell emigration from plaques. We examined whether statin activation of the SREBP pathway in vivo would induce CCR7 expression and promote macrophage emigration from plaques. We found that western diet-fed apoE-/- mice treated with either atorvastatin or rosuvastatin led to a substantial reduction in the CD68+ cell content in the plaques despite continued hyperlipidemia. We also observed a significant increase in CCR7 mRNA in CD68+ cells from both the atorvastatin and rosuvastatin treated mice associated with emigration of CD68+ cells from plaques. Importantly, CCR7-/-/apoE-/- double knockout mice failed to display a reduction in CD68+ cell content upon statin treatment. Statins also affected the recruitment of transcriptional regulatory proteins and the organization of the chromatin at the CCR7 promoter to increase the transcriptional activity. Statins promote the beneficial remodeling of plaques in diseased mouse arteries through the stimulation of the CCR7 emigration pathway in macrophages. Therefore, statins may exhibit some of their clinical benefits by not only retarding the progression of atherosclerosis, but also accelerating its regression.
doi:10.1371/journal.pone.0028534
PMCID: PMC3232231  PMID: 22163030
24.  Dual Effect of Rosuvastatin on Glucose Homeostasis Through Improved Insulin Sensitivity and Reduced Insulin Secretion 
EBioMedicine  2016;10:185-194.
Statins are beneficial in the treatment of cardiovascular disease (CVD), but these lipid-lowering drugs are associated with increased incidence of new on-set diabetes. The cellular mechanisms behind the development of diabetes by statins are elusive. Here we have treated mice on normal diet (ND) and high fat diet (HFD) with rosuvastatin. Under ND rosuvastatin lowered blood glucose through improved insulin sensitivity and increased glucose uptake in adipose tissue. In vitro rosuvastatin reduced insulin secretion and insulin content in islets. In the beta cell Ca2 + signaling was impaired and the density of granules at the plasma membrane was increased by rosuvastatin treatment. HFD mice developed insulin resistance and increased insulin secretion prior to administration of rosuvastatin. Treatment with rosuvastatin decreased the compensatory insulin secretion and increased glucose uptake. In conclusion, our data shows dual effects on glucose homeostasis by rosuvastatin where insulin sensitivity is improved, but beta cell function is impaired.
Highlights
•Rosuvastatin lowered blood glucose in vivo most likely due to improved glucose uptake.•Rosuvastatin reduced insulin content and impaired Ca2 + signaling in beta cells leading to reduced insulin secretion.•Dual effects of rosuvastatin in HFD mice though decreased compensatory insulin secretion and increased glucose uptake.
Statins are a group of drugs used to lower blood cholesterol in individuals with a risk of developing cardiovascular disease. It has been shown in several studies that statins increase the risk of developing type 2 diabetes. This increased risk has not yet been explained. We have investigated the effect of rosuvastatin on blood glucose regulation in mice. We found that rosuvastatin has a beneficial effect on glucose uptake in muscles which results in lowered blood glucose. However, in the insulin producing beta cells rosuvastatin altered normal cell function something that might increase the risk of developing type 2 diabetes.
doi:10.1016/j.ebiom.2016.07.007
PMCID: PMC5006666  PMID: 27453321
Statin; Insulin secretion; Glucose uptake; Glucose homeostasis; Islet; Beta cell; Adipose tissue; Muscle; OGTT; Transmission electron microscopy; Ca2 + measurements
25.  HMG-CoA Reductase Inhibitors Bind to PPARα to Upregulate Neurotrophin Expression in the Brain and Improve Memory in Mice 
Cell metabolism  2015;22(2):253-265.
Summary
Neurotrophins are important for neuronal health and function. Here, statins, inhibitors of HMG-CoA reductase and cholesterol lowering drugs, were found to stimulate expression of neurotrophins in brain cells independent of the mevalonate pathway. Time-resolved fluorescence resonance energy transfer (FRET) analyses, computer-derived simulation, site-directed mutagenesis, thermal shift assay, and de novo binding followed by electrospray ionization tandem mass spectrometry (ESI-MS) demonstrates that statins serve as ligands of PPARα and that Leu331 and Tyr 334 residues of PPARα are important for statin binding. Upon binding, statins upregulate neurotrophins via PPARα-mediated transcriptional activation of cAMP-response element binding protein (CREB). Accordingly, simvastatin increases CREB and brain-derived neurotrophic factor (BDNF) in the hippocampus of Ppara null mice receiving full-length lentiviral PPARα, but not L331M/Y334D statin-binding domain-mutated lentiviral PPARα. This study identifies statins as ligands of PPARα, describes neurotrophic function of statins via the PPARα-CREB pathway, and analyzes the importance of PPARα in the therapeutic success of simvastatin in an animal model of Alzheimer's disease.
Graphical abstract
doi:10.1016/j.cmet.2015.05.022
PMCID: PMC4526399  PMID: 26118928

Results 1-25 (1295573)