Mevalonic Acid Research Articles

Fluvastatin inhibits mast cell degranulation without changing the cytoplasmic Ca 2+ level

We evaluated the pharmacological effect of statins (3-hydroxy-3-methylglutaryl-CoA reductase inhibitors) on mast cell degranulation in RBL-2H3 cells. A hydrophilic statin (pravastatin) did not inhibit degranulation induced by dinitrophenol-human serum albumin (DNP-HSA); in contrast, lipophilic statins (simvastatin, fluvastatin and atorvastatin) inhibited DNP-HSA-induced degranulation in that order. The inhibitory effects were completely attenuated by simultaneous treatment with 100–1000 µM mevalonic acid for 4 h. We used fluvastatin to clarify the mechanism of the statin-mediated inhibitory action of mast cell degranulation. Fluvastatin (3 µM) had no effect on Ca 2+ release from the endoplasmic reticulum or Ca 2+ influx in the DNP-HSA- or thapsigargin-stimulated cells. Fluvastatin treatment also had no effect on the total granule content of the cell or sensitivity to DNP-HSA and IgE. Fluvastatin (3 µM, 24 h treatment) also failed to affect the morphology, proliferation, and viability of RBL-2H3 cells. Geranylgeranyl transferase inhibitor, GGTI-286 (20 µM), but not farnesyl transferase inhibitor, FPTIII (20 µM), inhibited the DNP-HSA-induced degranulation. The GGTI-286-induced inhibitory action was not associated with a decrease in the cytoplasmic Ca 2+ level. In conclusion, fluvastatin at a lower concentration range inhibited DNP-HSA-induced degranulation without affecting the cytoplasmic Ca 2+ response and also without changing the amount of granule content and proliferation of the mast cells. The statin-induced inhibitory action may be mediated by the suppression of geranylgeranyl transferase via the depletion of intracellular mevalonic acid.

QSAR and complex network study of the chiral HMGR inhibitor structural diversity

Efficient drugs such as statins or mevinic acids are inhibitors of the rate-limiting enzyme of cholesterol biosynthesis, 3-hydroxy-3-methyl-glutaryl coenzyme A reductase (HMGR), an enzyme responsible for the double reduction of 3-hydroxy-3-methyl-glutaryl coenzyme A into mevalonic acid. These compounds promoted the synthesis and evaluation of new inhibitors for HMGR, named HMGRIs. The high number of possible candidates creates the necessity of Quantitative Structure–Activity Relationship models in order to guide the HMGRI synthesis. There are two main problems of the reported QSAR models: the homogeneous series of the compounds and the chirality of many candidates. In this work, we propose for the first time a QSAR model for a very large and heterogeneous series of HMGRIs. The model is based on the Topological Indices (TIs) of molecular structures. Using the predictions of this model as input, we construct the first complex network that describes the drug–drug similarity relationships for more than 1600 experimentally non-explored chiral HMGRIs isomers. We also presented a reduced version of this network (Giant Component) that contains the most representative set of chiral HMGRI candidates. The work suggests a new mixed application in the QSAR study of relevant aspects of structural diversity by using chiral/non-chiral TIs, combined with complex networks.

Peroxisomal Localization of Arabidopsis Isopentenyl Diphosphate Isomerases Suggests That Part of the Plant Isoprenoid Mevalonic Acid Pathway Is Compartmentalized to Peroxisomes

Isoprenoids, the largest family of natural products, play numerous vital roles in basic plant processes, including photosynthesis, growth and development, reproduction, plant defense, and adaptation to environmental conditions ([Gershenzon and Kreis, 1999][1]; [Rodriguez-Concepcion and Boronat, 2002

Induction of Scavenger Receptor Class B Type I Is Critical for Simvastatin Enhancement of High-Density Lipoprotein-Induced Anti-Inflammatory Actions in Endothelial Cells

Changes in plasma lipoprotein profiles, especially low levels of high-density lipoprotein (HDL), are a common biomarker for several inflammatory and immune diseases, including atherosclerosis and rheumatoid arthritis. We examined the effect of simvastatin on HDL-induced anti-inflammatory actions. HDL and sphingosine 1-phosphate (S1P), a bioactive lipid component of the lipoprotein, inhibited TNF alpha-induced expression of VCAM-1, which was associated with NO synthase (NOS) activation, in human umbilical venous endothelial cells. The HDL- but not S1P-induced anti-inflammatory actions were enhanced by a prior treatment of the cells with simvastatin in a manner sensitive to mevalonic acid. Simvastatin stimulated the expression of scavenger receptor class B type I (SR-BI) and endothelial NOS. As for S1P receptors, however, the statin inhibited the expression of S1P(3) receptor mRNA but caused no detectable change in S1P(1) receptor expression. The reconstituted HDL, a stimulator of SR-BI, mimicked HDL actions in a simvastatin-sensitive manner. The HDL- and reconstituted HDL-induced actions were blocked by small interfering RNA specific to SR-BI regardless of simvastatin treatment. The statin-induced expression of SR-BI was attenuated by constitutively active RhoA and small interfering RNA specific to peroxisome proliferator-activated receptor-alpha. Administration of simvastatin in vivo stimulated endothelial SR-BI expression, which was accompanied by the inhibition of the ex vivo monocyte adhesion in aortas from TNF alpha-injected mice. In conclusion, simvastatin induces endothelial SR-BI expression through a RhoA- and peroxisome proliferator-activated receptor-alpha-dependent mechanism, thereby enhancing the HDL-induced activation of NOS and the inhibition of adhesion molecule expression.

Abstract 237: Acute Activation of eNOS by Lovastatin Involves Scavenger Receptor-B1

Statins (HMG CoA reductase inhibitors) have beneficial vascular effects independent of their ability to reduce cholesterol synthesis. We and others have previously shown that statins acutely activate endothelial cell NOS (eNOS). Our present study characterized signaling pathways by which statins activate NOS using cultured bovine aortic endothelial cells (BAEC) and COS 7 cells. It also examined involvement of scavenger receptor - B1 (SR-B1), which is expressed in endothelial cells and maintains caveolae cholesterol concentration and eNOS localization. BAEC were exposed to lovastatin (LOV, 10 −6 M) for 2–5 min after pretreatment with the end product of HMG CoA reductase (mevalonic acid, 5×10 −4 M), a Gi protein inhibitor (pertussis toxin, 10 −4 M), a PLC inhibitor (U-73122, 10 −5 M), a receptor tyrosine kinase (RTK) inhibitor (tyrphostine 51A, 2×10 −6 M) or intracellular and extracellular calcium chelators -BAPTA-AM (10 −5 M) and EGTA (10 −4 M), respectively, and levels of NO production were determined. LOV alone acutely increased NO production by 67%. NO production in response to LOV was not blocked by mevalonic acid indicating that it occurs independent of HMG CoA reductase inhibition. Inhibition of Gi protein, PLC, and RTK almost completely blocked the LOV-induced NO generation. Removal of extracellular Ca ++ prevented statin-induced NO production by 90%, while intracellular Ca ++ chelation with BAPTA-AM reduced NO production by 45%. COS 7 cells transfected with eNOS did not show increased NO production to LOV or HDL, indicating NOS activation occurs through an endothelial cell receptor. In COS 7 cells, co-transfected with eNOS and the endothelial SR-B1, LOV or HDL (10 −5 M), a known agonist of SR-B1, increased NO production by over 200%. In COS 7 cells transfected with eNOS alone or co-transfected with the bradykinin B2 receptor, neither LOV nor HDL increased NO production, indicating effects specific for the SR-B1 receptor. In conclusion, our study shows LOV acutely activates eNOS independently of HMG CoA reductase inhibition. eNOS activation appears to involve an endothelial Gi protein receptor and subsequent activation of PLC and RTK pathways, leading to entry of extracellular calcium. Furthermore, LOV can activate eNOS via the SR-B1 receptor.

Abstract 5517: A Novel Tissue Engineered Skeletal Muscle Screening Platform to Assess the Myotoxic Potential of Statins

Our study had two objectives: to develop a novel tissue engineered skeletal muscle drug screening platform and to assess myotoxicity of various statins and identify underlying mechanisms. Methods: Engineered skeletal muscle tissue (SMT) was generated from adult rat skeletal myoblasts, rat fibroblasts (1.25x106 cells/SMT), matrigel, and collagen. Reconstitution-mixtures (450 μl) were poured into circular moulds yielding ring-shaped constructs after 5 days. SMTs were cultured for additional 10 days on stretch devices and treated with increasing concentrations of statins or vehicle for the last 5 culture days. Force of contraction (FOC) was measured and SMTs subjected to either immune fluorescence (IF), HE-staining or Western blotting (WB). Results: SMTs displayed differentiated muscle bundles (actin-IF and HE) and elicited tetanic contractions with maximal force at 60 Hz (1.3±0.2 mN; n=5). Carbachol (1 μM) induced a reversible block of muscle contraction which was antagonized by pancuronium (10 μM) indicating the presence and functionality of nicotinergic acetylcholine receptors. Statin treatment caused a concentration-dependent decrease in FOC in the following order of potency (EC50): cerivastatin (10 nM), simvastatin (100 nM), atorvastatin (350 nM), pravastatin (1860 nM; n=6–8/group and concentration). Contractile failure was paralleled by sarcomere breakdown and apoptosis (IF and WB: reduced actin, increased caspase 3). To assess the mechanism of statin myotoxicity, we investigated the protective effects of mevalonic acid (MEV, 100 μM), farnesyl-pyrophosphate (F-PP, 10 μM), squalene (S, 10 μM), and geranyl-geranyl-pyrophophate (G-PP, 10 μM) in the presence of maximally toxic cerivastatin concentrations (1 μM; complete contractile failure). MEV prevented cerivastatin toxicity completely (FOC: 102.3±16% of vehicle; n=7). GG-PP partially prevented cerivastatin-induced contractile failure (FOC: 53.3±14% of vehicle; n=4). S and F-PP had no protective effect (n=4/group). Conclusion: SMT can be used to identify and compare statin myotoxicity in vitro and may be useful to dissect its underlying mechanisms. In addition, our data suggests that statin myotoxicity is at least in part independent of cholesterol depletion.

Hyper-IgD syndrome with novel mutation in a Japanese girl

Hyperimmunoglobulin D and periodic fever syndrome (HIDS) is an autosomal recessive auto-inflammatory disorder characterized by recurrent febrile attacks with lymphadenopathy, abdominal distress, skin eruptions and joint involvement. We discuss the case of a 15-year-old Japanese girl who had presented with periodic fever, hepatosplenomegaly and intractable diarrhea from seven weeks of age. At first, undifferentiated autoimmune disorder was suspected, and she was treated with prednisolone and, in turn, with immunosuppressants such as cyclosporine, methotrexate, cyclophosphamide and rituximab or with plasma exchange. However, these trials failed to relieve her symptoms, and so she was transferred to our hospital when she was 15 years old. Her parents and elder brother had no history of recurrent fever, prolonged abdominal pain or diarrhea of unknown origin. The patient had extremely elevated levels of mevalonic aciduria and had homozygosity as a novel mutation in the MVK gene (G326R). Finally, HIDS was diagnosed. She was treated with simvastatin, which resulted in a moderate decrease of the urinary mevalonic acid concentration and good clinical course. This is the first case in which homozygosity for the mutation of the MVK gene has been reported in an Asian patient, and indicated a need for differentiation.

Myopathies associated with red yeast rice and liquorice: spontaneous reports from the Italian Surveillance System of Natural Health Products

Many drugs can be responsible for muscle injuries. Besides statins, recognised as the drugs most commonly associated with severe myopathies, other medications such as neuroleptics, proton pump inhibitors and recently gabapentin [1] have been associated with this type of adverse drug reaction (ADR). Recent case reports have highlighted that active compounds from medicinal plants can also be responsible for myopathies [2, 3], including rhabdomyolysis but a systematic evaluation of reporting databases is still lacking. In the present study, the Italian ADR database [4, 5] of natural health products was analyzed with the aim of evaluating the possible ‘signal alarms’ due to herbal medicines and muscle injuries. A panel of experts, including a medical toxicologist, a pharmacist and a physician expert in herbal medicine reviewed all reports of myopathy to define the causality assessment using the Naranjo probability scale [6]. From April 2002 to December 2007, nine reports of muscle disorders were identified, of which seven were reported by phytotherapy specialists, one by a hospital physician, and one by a general practitioner. As shown in Table 1 most disorders (7/9) were due to red yeast rice (Monascus purpureus) (n = 4) and liquorice (n = 3) (Glycyrrhiza glabra). In all reports Monascus purpureus was used to treat hypercholesterolaemia, and all events were assessed as ‘probable’, according to the Naranjo probability scale; all cases showed increased concentrations of serum creatinine phosphokinase (CPK) and their onset varied from 2 to 6 months. One of the patients reported previous statin intolerance, while the one who showed the highest increase in CPK (401 IU l−1; normal range 24–195 IU l−1) reported concurrent muscle pain. In the latter case the ADR did not resolve after discontinuation of red yeast rice. Table 1 Reports of myopathies associated with use of herbal drugs A case of rhabdomyolysis was diagnosed after 3 months of liquorice consumption (30–40 g day−1) but signs and symptoms disappeared after dechallenge. Laboratory data were unavailable. Another patient presented with a remarkable increase in CPK (8000 IU l−1) and blood nitrogen (6.0 mg dl−1, normal range: 0.2–6.0 mg l−1) after 20 days of self-administration of a laxative product containing liquorice. At a 6-month follow up, CPK concentrations were still elevated. Causality was assessed as ‘possible’ since the patient had undergone a previous 8-year consumption of simvastatin and lansoprazole, two drugs possibly associated with muscle injury. Although both drugs were stopped several weeks before the onset of rhabdomyolysis, their previous consumption was taken into account when assessing the causality relationship. A case of hypertension, hypokalaemia, hypernatraemia and increased CPK was also reported after 3 months of liquorice juice consumption as self-medication for chronic hypotension. After dechallenge and anti-aldosterone treatment, the patient completely recovered. According to a WHO critical term list, all reports referring to liquorice consumption were classified as ‘serious’ due to hospital admission and two out of three reactions were assessed as ‘probable’. In two cases, symptoms completely resolved after product discontinuation. Major alternative causes of muscle disorders, including alcohol abuse, illicit drug use, infections, metabolic, endocrine or inflammatory diseases were excluded in all seven patients. We can confirm the recent ‘signal’ seen in the medical literature of case reports of muscle disorders associated with red yeast rice and liquorice through our analysis of the Italian national database of adverse reactions to natural health products. All reported cases of ADRs are biologically plausible and supported by preclinical and physiopathological rationale. For instance, chronic or acute liquorice use, through glycyrrhizic acid, is able to inhibit 11β-hydroxysteroid deydrogenase-2 impairing lipid metabolism in muscle cells [3], while Monascus purpureus contains mevalonic acid and Monacolin K, an agent that has the same structure and activity as lovastatin [2, 7]. Although some case reports [4, 8, 9] have already raised this concern, favourable attitudes towards herbal preparations are still strong in industrialized countries [10]. In the majority of the cases reported here, red yeast rice was used to treat dyslipidaemia, often as a self-medication, without a physician's and/or pharmacist's supervision. Many patients could therefore be exposing themselves dangerously to the additive effect of herbal and synthetic drugs, such as statins, whose potential adverse effect on muscle is well documented. Moreover, a previous statin intolerance constitutes a critical point for red yeast rice use; this should be taken into account by physicians when suggesting this kind of natural remedy to their patients, as well as by statin-intolerant patients seeking natural alternatives to synthetic drugs, who might be unaware of the real benefit–harm profile of these products.

Simvastatin inducing PC3 prostate cancer cell necrosis mediated by calcineurin and mitochondrial dysfunction

In the present study we analyzed the mechanisms of simvastatin toxicity for the PC3 human prostate cancer cell line. At 10 microM, simvastatin induced principally apoptosis, which was prevented by mevalonic acid but not by cyclosporin A, the inhibitor of calcineurin and mitochondrial permeability transition (MPT). At 60 microM, simvastatin induced the necrosis of PC3 cells insensitive to mevalonic acid. Cell necrosis was preceded by a threefold increase in cytosolic free Ca(2+) concentration and a significant decrease in both respiration rate and mitochondrial membrane potential. Both mitochondrial dysfunction and necrosis were sensitive to the compounds cyclosporin A and bongkrekic acid, as well as the calcineurin inhibitor FK506. We have concluded that simvastatin-induced PC3 cells apoptosis is dependent on 3-hydroxy-3-methylglutaryl coenzyme-A reductase inhibition and independent of MPT, whereas necrosis is dependent on mitochondrial dysfunction caused, at least in part, by calcineurin.

Differential interaction of branch-specific inhibitors of isoprenoid biosynthesis with cell cycle progression in tobacco BY-2 cells

3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGR), which catalyzes the formation of mevalonic acid (MVA), can be specifically blocked by mevinolin. Inhibition of HMGR in vivo leads to an arrest in cell cycle progression in tobacco (Nicotiana tabacum L. Bright Yellow 2) cells. As MVA in plants is the common precursor of a myriad of isoprenoid products synthesized in the cytosol and mitochondria, it is difficult to identify among such MVA-dependent molecules those whose lack may lead to cell cycle arrest. In an attempt to do so, branch-specific inhibitors of the cytosolic isoprenoid pathway downstream from MVA were used to study their capacity to block cell cycle progression. The effects of squalestatin (sterol biosynthesis inhibitor), chaetomellic acid A and patulin (protein prenyltransferase (PT) inhibitors) and tunicamycin (inhibitor of dolichol-dependent protein glycosyl transferase, thus mimicking the effect of an absence of dolichol) were compared to those induced by mevinolin. In this way, squalestatin and chaetomellic acid were identified as behaving like true cell cycle inhibitors, in that they led to a specific arrest in the cell cycle. However, they did not exactly mimic the mevinolin-induced effects. Patulin proved to be of high general toxicity, which suggests that it may affect other reactions besides blockage of protein isoprenylation. Finally, tunicamycin efficiently blocked growth of cell suspension cultures, but did not arrest the cells in a specific phase of the cell cycle. Results are discussed in the context of a better understanding of the essential implication of isoprenoids in plant cell cycle progression.

Statins Are Safe for the Treatment of Hypercholesterolemia in Patients With Chronic Liver Disease

Statins Are Safe for the Treatment of Hypercholesterolemia in Patients With Chronic Liver Disease

Ecdysteroids in spinach (Spinacia oleracea L.): Biosynthesis, transport and regulation of levels

Many plant species produce phytoecdysteroids (PEs: i.e. analogues of insect steroid hormones). There is increasing evidence that PEs are used as a chemical defence by plants against non-adapted insects and nematodes. PEs are good candidates for the development of an environmentally safe approach to crop protection. Most crop species do not accumulate PEs. However, many arguments support the idea that most, if not all, plant species have the genetic ability to produce PEs, but the biosynthetic pathway is not active. A better understanding of the PE biosynthetic pathway and its regulation is consequently necessary. Spinach is one of the very few crop plants which produce large amounts of PEs, of which 20-hydroxyecdysone is the major component. Labeling experiments with radiolabeled precursor (mevalonic acid), putative ecdysteroid intermediates and 20-hydroxyecdysone itself have allowed investigation of PE biosynthesis and transport during spinach development. Biosynthesis takes place in older leaf sets ("sources"), but not in the young developing ones, which in contrast accumulate (acting as "sinks") the PEs produced by the older leaves. PEs are thus continuously redistributed within the developing plant, as its leaf set number increases. The biosynthetic pathway has been analyzed using excised leaves and various labeled precursors, and a preferential sequence of the last steps has been established. Although they do not produce PEs, apical leaf sets are nevertheless able to perform several putative terminal steps of PE biosynthesis. The regulatory mechanisms of PE synthesis appear to involve a direct negative feedback of 20-hydroxyecdysone (the major PE in spinach) on its own synthesis; thus, a sustained synthesis in older leaves requires that they can export the PE they produce.

Rapid TLC Method for Estimation of Mevalonic Acid in the Leaves of Medicinal Plants

A simple, rapid, specific and sensitive thin layer chromatographic (TLC) method has been developed for the quantitative estimation of mevalonic acid (MVA) in leaves of medicinal plants; Artemisia annua, Psorelia corylifolia, Vinca rosea, Withania somnifera and Barleria proinites. The assay procedure involved conversion of MVA to its lactone, mevalonolactone (MVAL). Mevalonic acid was extracted from the leaf tissues of plants. Separation of MVAL was carried out on silica gel 60 F254 TLC plates using benzene:acetone (3:2) as the mobile phase. The densitometric determination of MVAL was performed at 600 nm after derivatization with anisaldehyde reagent in absorption–reflectance mode. The method was validated over the linearity range of 100–500 ng spot−1 and correlation coefficient for the calibration curve was >0.99. The average recovery of MVAL, used as internal standard, was higher than 98%. The lower limit of detection was found to be 50 ng spot−1.

A patient with hyper-IgD syndrome responding to simvastatin treatment

The hyper-IgD syndrome (HIDS) is an autosomal recessively inherited auto-inflammatory syndrome, caused by deficient enzyme activity of mevalonate kinase (MVK), an enzyme in the isoprenoid pathway. Patients present with a long history of recurrent fever attacks, accompanied by abdominal pain, skin lesions, lymphadenopathy and arthralgia. The attacks last about 3–7 days followed by a spontaneous remission, only to recur after a symptom-free period of 4–6 weeks. Factors known to precipitate an attack are infection, trauma, vaccination, and psychological stress. Laboratory examination at the time of attacks reveals a vigorous acute phase response with leucocytosis, raised sedimentation rate, high serum concentrations of C-reactive protein and increased mevalonic acid urinary levels. Almost all patients have an elevated polyclonal immunoglobulin D. Until now, treatment of HIDS patients is largely supportive and very difficult. Various anti-inflammatory drugs have failed to suppress the fever attacks [ [1] Haas D. Hoffmann G. Mevalonate kinase deficiencies: from mevalonic aciduria to hyperimmunoglobulinemia D syndrome. Orphanet J Rare Dis. 2006 Apr; : 1-13 Google Scholar ].

Increase of Serum Cholesterol Levels by Heat‐Moisture‐Treated High‐Amylose Cornstarch in Rats Fed a High‐Cholesterol Diet

The effects of four cornstarches containing various contents of resistant starch on serum and liver cholesterol levels in rats fed a high-cholesterol diet were investigated. Male Sprague Dawley rats (aged 4 weeks) were divided into four groups (n = 7) and fed high-cholesterol diets containing 15% of cornstarch (CS), heat-moisture-treated CS (HCS), high-amylose CS (HA), or heat-moisture-treated HA (HHA) for 21 days. The results showed that the serum and hepatic level of total cholesterol, LDL-cholesterol, and triglyceride in rats of the HHA group and their arteriosclerosis index were significantly higher, suggesting that HHA increases the risk of arteriosclerosis under a high-cholesterol dietary condition. No significant between-group differences were noted in the levels of plasma mevalonic acid and hepatic HMG-CoA reductase mRNA, whereas fecal cholesterol excretion was significantly higher in the HHA group, indicating that the elevation of the serum and liver cholesterol levels was not due to the promotion of liver cholesterol synthesis and cholesterol absorption in the intestine.

Participation of K+ Channels in the Endothelium-Dependent and Endothelium-Independent Components of the Relaxant Effect of Rosuvastatin in Rat Aortic Rings

Rosuvastatin was tested on rat aortic rings in the presence and absence of K(+) channel blockers, mevalonic acid, and inhibitors of nitric oxide, prostaglandins, or endothelial-derived hyperpolarizing factor synthesis. The direct vascular effects of rosuvastatin were then evaluated by obtaining dose-response curves. Rosuvastatin relaxed aortic rings with and, to a lesser degree, without endothelium. Under both these conditions this effect was partially inhibited by L-NAME, tetraethylammonium, apamin + charybdotoxin (only administered together), or mevalonic acid. The combination of L-NAME with any of the other 3 treatments completely inhibited the effect of rosuvastatin, but indomethacin, clotrimazol, glibenclamide, charybdotoxin, or apamin alone had no effect. Therefore, the relaxation induced by rosuvastatin, even in the absence of endothelium, is partially related to 2 different mechanisms, one that is isoprenoid dependent and NO mediated and the other that is tied to the opening of Ca( 2+)-dependent K(+) channels of the slow subfamily.

Simvastatin Inhibits IL-17 Secretion by Targeting Multiple IL-17-Regulatory Cytokines and by Inhibiting the Expression of IL-17 Transcription Factor RORC in CD4+ Lymphocytes

Statins, extensively used as cholesterol-lowering agents, have recently been identified as immunomodulatory agents. This study investigated the statins' mechanisms that target the autoimmune response in humans, and evaluated their therapeutic potential in multiple sclerosis. Our results demonstrated statin-mediated increases in suppressor of cytokine secretion (SOCS) 3 and suppressor of cytokine secretion 7, which negatively regulate the STAT/JAK signal transduction pathway and IL-6 and IL-23 gene expression in monocytes. Simvastatin also induced IFN-gamma, IL-4, and IL-27 production in monocytes, which together inhibited IL-17 transcription and secretion in CD4(+) T cells. IL-17-producing CD4(+) cells, referred to as Th17 cells, have recently been found to play a central role in the development of autoimmune diseases. Furthermore, simvastatin directly inhibited the expression of retinoic acid-related orphan nuclear hormone receptor C, a transcription factor that controls IL-17 production in CD4(+) T cells. This effect was reversed by mevalonic acid, a downstream metabolite of 3-hydroxy-3-methylglutaryl CoA reductase, confirming that simvastatin's specific effect is through the inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase. These results provide evidence for the novel immunomodulatory mechanisms of statins, which selectively target the regulation of cytokine transcription involved in the development of the human autoimmune response. Based on the described immunomodulatory mechanisms, good safety profile and oral bioavailability, statins represent a promising therapeutic approach for multiple sclerosis and other chronic inflammatory diseases.

Fifty Years of the Synthesis of Labelled Mevalonic Acid

This article reviews developments in the synthesis of isotopically-labelled samples of mevalonic acid for use in studies of terpenoid and steroid biosynthesis.

Simvastatin suppresses the differentiation of C2C12 myoblast cells via a Rac pathway

Statins, which are known as cholesterol-lowering drugs, have several additional effects including the enhancement of bone formation and the stimulation of smooth muscle cell proliferation. In this study, we investigated the signal pathway of simvastatin operating in C2C12 myoblast cells. Myotube formation of C2C12 cells was efficiently blocked by 1 muM simvastatin, and mevalonic acid was able to cancel this effect. Geranylgeranyl pyrophosphate restored the myotube formation, whereas farnesyl pyrophosphate did not. These findings demonstrate that the Rho family, such as Rho, Rac and Cdc42, occurring downstream of geranylgeranyl pyrophosphate in the mevalonic acid pathway, was involved in the simvastatin-mediated blockage of myotube formation. An inhibitor of Rho kinase did not influence the myotube formation; whereas an inhibitor of Rac blocked this process. Taken together, we conclude that the differentiation of C2C12 cells into myotubes was blocked by simvastatin through the pathway mediated by Rac, not by Rho.

Bioconversion of lovastatin to a novel statin by Amycolatopsis sp.

3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase catalyzes the conversion of HMG-CoA to mevalonic acid, which plays a significant role in cholesterol synthesis. Several statins, inhibitors of HMG-CoA reductase, can be synthesized and converted by microorganisms. Among 700 strains obtained from culture collections, one strain could convert lovastatin to a novel statin, wuxistatin. The strain was identified as a member of the genus Amycolatopsis based on 16S rRNA gene sequence, morphology analysis, and chemotaxonomic properties. Wuxistatin, a novel HMG-CoA reductase inhibitor, was purified by chromatography, and the structure was determined by electrospray ionization mass and nuclear magnetic resonance spectroscopy. The results show that wuxistatin was butanoic acid, 2-methyl-,1,2,3,5,8,8a-hexahydro-5-hydroxy-7-methyl-8-[2-(tetrahydro-4-hydroxy-6-oxo-2H-pyran-2-yl) ethy]-1-naphthalenyl ester. An additional hydroxyl group was added to lovastatin at the 5-position to yield wuxistatin. This modification enhanced the intrinsic inhibitory activity (IC50) ofwuxistatin (41+/-5 nM) for fourfold compared with lovastatin (160+/-10 nM). A stoichiometric conversion of lovastatin to wuxistatin occurred.