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Sample records for aldosterone synthase inhibitor

  1. Synthesis of annulated pyridines as inhibitors of aldosterone synthase (CYP11B2).

    PubMed

    Martin, Rainer E; Lehmann, Johannes; Alzieu, Thibaut; Lenz, Mario; Carnero Corrales, Marjorie A; Aebi, Johannes D; Märki, Hans Peter; Kuhn, Bernd; Amrein, Kurt; Mayweg, Alexander V; Britton, Robert

    2016-07-01

    A series of cyclopenta[c]pyridine aldosterone synthase (AS) inhibitors were conveniently accessed using batch or continuous flow Kondrat'eva reactions. Preparation of the analogous cyclohexa[c]pyridines led to the identification of a potent and more selective AS inhibitor. The structure-activity-relationship (SAR) in this new series was rationalized using binding mode models in the crystal structure of AS. PMID:27245438

  2. Discovery and in Vivo Evaluation of Potent Dual CYP11B2 (Aldosterone Synthase) and CYP11B1 Inhibitors.

    PubMed

    Meredith, Erik L; Ksander, Gary; Monovich, Lauren G; Papillon, Julien P N; Liu, Qian; Miranda, Karl; Morris, Patrick; Rao, Chang; Burgis, Robin; Capparelli, Michael; Hu, Qi-Ying; Singh, Alok; Rigel, Dean F; Jeng, Arco Y; Beil, Michael; Fu, Fumin; Hu, Chii-Whei; LaSala, Daniel

    2013-12-12

    Aldosterone is a key signaling component of the renin-angiotensin-aldosterone system and as such has been shown to contribute to cardiovascular pathology such as hypertension and heart failure. Aldosterone synthase (CYP11B2) is responsible for the final three steps of aldosterone synthesis and thus is a viable therapeutic target. A series of imidazole derived inhibitors, including clinical candidate 7n, have been identified through design and structure-activity relationship studies both in vitro and in vivo. Compound 7n was also found to be a potent inhibitor of 11β-hydroxylase (CYP11B1), which is responsible for cortisol production. Inhibition of CYP11B1 is being evaluated in the clinic for potential treatment of hypercortisol diseases such as Cushing's syndrome. PMID:24900631

  3. A particular phenotype in a girl with aldosterone synthase deficiency.

    PubMed

    Williams, Tracy A; Mulatero, Paolo; Bosio, Maurizio; Lewicka, Sabina; Palermo, Mario; Veglio, Franco; Armanini, Decio

    2004-07-01

    Aldosterone synthase deficiency (ASD) usually presents in infancy as a life-threatening electrolyte imbalance. A 4-wk-old child of unrelated parents was examined for failure to thrive and salt-wasting. Notable laboratory findings were hyperkalemia, high plasma renin, and low-normal aldosterone levels. Urinary metabolite ratios of corticosterone/18-hydroxycorticosterone and 18-hydroxycorticosterone/aldosterone were intermediate between ASD type I and type II. Sequence analysis of CYP11B2, the gene encoding aldosterone synthase (P450c11AS), revealed that the patient was a compound heterozygote carrying a previously described mutation located in exon 4 causing a premature stop codon (E255X) and a further, novel mutation in exon 5 that also causes a premature stop codon (Q272X). The patient's unaffected father was a heterozygous carrier of the E255X mutation, whereas the unaffected mother was a heterozygous carrier of the Q272X mutation. Therefore, the patient's CYP11B2 encodes two truncated forms of aldosterone synthase predicted to be inactive because they lack critical active site residues as well as the heme-binding site. This case of ASD is of particular interest because despite the apparent lack of aldosterone synthase activity, the patient displays low-normal aldosterone levels, thus raising the question of its source. PMID:15240589

  4. Discovery of 4-Aryl-5,6,7,8-tetrahydroisoquinolines as Potent, Selective, and Orally Active Aldosterone Synthase (CYP11B2) Inhibitors: In Vivo Evaluation in Rodents and Cynomolgus Monkeys.

    PubMed

    Martin, Rainer E; Aebi, Johannes D; Hornsperger, Benoit; Krebs, Hans-Jakob; Kuhn, Bernd; Kuglstatter, Andreas; Alker, André M; Märki, Hans Peter; Müller, Stephan; Burger, Dominique; Ottaviani, Giorgio; Riboulet, William; Verry, Philippe; Tan, Xuefei; Amrein, Kurt; Mayweg, Alexander V

    2015-10-22

    Inappropriately high levels of aldosterone are associated with many serious medical conditions, including renal and cardiac failure. A focused screen hit has been optimized into a potent and selective aldosterone synthase (CYP11B2) inhibitor with in vitro activity against rat, mouse, human, and cynomolgus monkey enzymes, showing a selectivity factor of 160 against cytochrome CYP11B1 in the last species. The novel tetrahydroisoquinoline compound (+)-(R)-6 selectively reduced aldosterone plasma levels in vivo in a dose-dependent manner in db/db mice and cynomolgus monkeys. The selectivity against CYP11B1 as predicted by cellular inhibition data and free plasma fraction translated well to Synacthen challenged cynomolgus monkeys up to a dose of 0.1 mg kg(-1). This compound, displaying good in vivo potency and selectivity in mice and monkeys, is ideally suited to perform mechanistic studies in relevant rodent models and to provide the information necessary for translation to non-human primates and ultimately to man. PMID:26403853

  5. Different effects of progesterone and estradiol on chimeric and wild type aldosterone synthase in vitro

    PubMed Central

    2013-01-01

    Background Familial hyperaldosteronism type I (FH-I) is caused by the unequal recombination between the 11beta-hydroxylase (CYP11B1) and aldosterone synthase (CYP11B2) genes, resulting in the generation of a CYP11B1/B2 chimeric gene and abnormal adrenal aldosterone production. Affected patients usually show severe hypertension and an elevated frequency of stroke at a young age. Aldosterone levels rise during pregnancy, yet in pregnant women with FH-1, their hypertensive condition either remains unchanged or may even improve. The purpose of this study was to investigate in vitro whether female sex steroids modulate the activity of chimeric (ASCE) or wild type (ASWT) aldosterone synthase enzymes. Methods We designed an in vitro assay using HEK-293 cell line transiently transfected with vectors containing the full ASCE or ASWT cDNAs. Progesterone or estradiol effects on AS enzyme activities were evaluated in transfected cells incubated with deoxycorticosterone (DOC) alone or DOC plus increasing doses of these steroids. Results In our in vitro model, both enzymes showed similar apparent kinetic parameters (Km = 1.191 microM and Vmax = 27.08 microM/24 h for ASCE and Km = 1.163 microM and Vmax = 36.98 microM/24 h for ASWT; p = ns, Mann–Whitney test). Progesterone inhibited aldosterone production by ASCE- and ASWT-transfected cells, while estradiol demonstrated no effect. Progesterone acted as a competitive inhibitor for both enzymes. Molecular modelling studies and binding affinity estimations indicate that progesterone might bind to the substrate site in both ASCE and ASWT, supporting the idea that this steroid could regulate these enzymatic activities and contribute to the decay of aldosterone synthase activity in chimeric gene-positive patients. Conclusions Our results show an inhibitory action of progesterone in the aldosterone synthesis by chimeric or wild type aldosterone synthase enzymes. This is a novel regulatory mechanism of progesterone

  6. Thymidylate synthase inhibitors.

    PubMed

    Danenberg, P V; Malli, H; Swenson, S

    1999-12-01

    Thymidylate synthase (TS) is a critical enzyme for DNA replication and cell growth because it is the only de novo source of thymine nucleotide precursors for DNA synthesis. TS is the primary target of 5-fluorouracil (5-FU), which has been used for cancer treatment for more than 40 years. However, dissatisfaction with the overall activity of 5-FU against the major cancers, and the recognition that TS still remains an attractive target for anticancer drugs because of its central position in the pathway of DNA synthesis, led to a search for new inhibitors of TS structurally analogous to 5,10-methylenetetrahydrofolate, the second substrate of TS. TS inhibitory antifolates developed to date that are in various stages of clinical evaluation are ZD 1694 and ZD9331 (Astra-Zeneca, London, UK), (Eli Lilly, Indianapolis, IN), LY231514 (BW1843U89 (Glaxo-Wellcome, Research Triangle Park, NC), and AG337 and AG331 (Agouron, La Jolla, CA). Although each of these compounds has TS as its major intracellular site of action, they differ in propensity for polyglutamylation and for transport by the reduced folate carrier. LY231514 also has secondary target enzymes. As a result, each compound is likely to have a different spectrum of antitumor activity and toxicity. This review will summarize the development and properties of this new class of TS inhibitors. PMID:10606255

  7. Aldosterone, Parathyroid Hormone, and the Use of Renin-Angiotensin-Aldosterone System Inhibitors: The Multi-Ethnic Study of Atherosclerosis

    PubMed Central

    Brown, Jenifer; de Boer, Ian H.; Robinson-Cohen, Cassianne; Siscovick, David S.; Kestenbaum, Bryan; Allison, Matthew

    2015-01-01

    Context: Aldosterone and PTH are implicated in the pathogenesis of cardiovascular and skeletal diseases. An expanding body of evidence supports a bidirectional and positive physiologic relationship between aldosterone and PTH. Large population-based studies confirming this relationship, and whether it may be targeted as a potential method to mitigate the clinical consequences associated with excess aldosterone and PTH, are needed. Objective: We hypothesized that higher aldosterone levels would associate with higher PTH, and that the use of renin-angiotensin-aldosterone system (RAAS) inhibitors would predict lower PTH in a large, multi-ethnic, community-based cohort. Design, Setting, Participants: We conducted cross-sectional analyses of participants in the Multi-Ethnic Study of Atherosclerosis without apparent primary hyperparathyroidism or chronic kidney disease (n = 5668). We evaluated associations of RAAS inhibitor use with PTH concentration among 1888 treated hypertensive participants. We also tested associations of serum aldosterone concentration with PTH concentration among 1547 participants with these measurements. Outcome: Serum PTH concentration. Results: Higher aldosterone associated with higher PTH (β = 0.19 pg/ml per 1 ng/dl of aldosterone, P < .0001), and this finding was most pronounced among those with a primary hyperaldosteronism-like phenotype. There was a stepwise increment in PTH when comparing untreated normotensives, hypertensives using RAAS inhibitors, untreated hypertensives, and treated hypertensives using non-RAAS inhibitors (40.8, 45.0, 46.2, 47.1 pg/ml, respectively). The use of any RAAS inhibitor independently associated with lower PTH (β = −2.327 pg/ml per use of RAAS inhibitor, P = .006), when compared with the use of any non-RAAS inhibitor medication. Conclusions: Higher serum aldosterone concentration is associated with higher serum PTH concentration, and the use of RAAS inhibitors is associated with lower PTH concentration

  8. Molecular identity and gene expression of aldosterone synthase cytochrome P450

    SciTech Connect

    Okamoto, Mitsuhiro . E-mail: mokamoto@mr-mbio.med.osaka-u.ac.jp; Nonaka, Yasuki; Takemori, Hiroshi; Doi, Junko

    2005-12-09

    11{beta}-Hydroxylase (CYP11B1) of bovine adrenal cortex produced corticosterone as well as aldosterone from 11-deoxycorticosterone in the presence of the mitochondrial P450 electron transport system. CYP11B1s of pig, sheep, and bullfrog, when expressed in COS-7 cells, also performed corticosterone and aldosterone production. Since these CYP11B1s are present in the zonae fasciculata and reticularis as well as in the zona glomerulosa, the zonal differentiation of steroid production may occur by the action of still-unidentified factor(s) on the enzyme-catalyzed successive oxygenations at C11- and C18-positions of steroid. In contrast, two cDNAs, one encoding 11{beta}-hydroxylase and the other encoding aldosterone synthase (CYP11B2), were isolated from rat, mouse, hamster, guinea pig, and human adrenals. The expression of CYP11B1 gene was regulated by cyclic AMP (cAMP)-dependent signaling, whereas that of CYP11B2 gene by calcium ion-signaling as well as cAMP-signaling. Salt-inducible protein kinase, a cAMP-induced novel protein kinase, was one of the regulators of CYP11B2 gene expression.

  9. Aldosterone Induces Tissue Inhibitor of Metalloproteinases-1 Expression and Further Contributes to Collagen Accumulation: From Clinical to Bench Studies.

    PubMed

    Hung, Chi-Sheng; Chou, Chia-Hung; Liao, Che-Wei; Lin, Yen-Tin; Wu, Xue-Ming; Chang, Yi-Yao; Chen, Ying-Hsien; Wu, Vin-Cent; Su, Ming-Jai; Ho, Yi-Lwun; Chen, Ming-Fong; Wu, Kwan-Dun; Lin, Yen-Hung

    2016-06-01

    Aldosterone induces myocardial fibrosis. Tissue inhibitor of metalloproteinases-1 (TIMP-1) is a key factor of myocardial fibrosis. This study tested the hypothesis that aldosterone induces TIMP-1 expression and contributes to the fibrotic process. We prospectively enrolled 54 patients with primary aldosteronism, and measured plasma TIMP-1 and echocardiographic parameters. In the cell study, we investigated the possible molecular mechanism by which aldosterone induces TIMP-1 secretion and the effects on collagen accumulation. In the animal study, we measured serum TIMP-1 levels, cardiac TIMP-1 levels, and cardiac structure in an aldosterone infusion mouse model using implantation of aldosterone pellets. In patients with primary aldosteronism, plasma TIMP-1 was correlated with 24-hour urinary aldosterone, left ventricular mass, and impairment of left ventricular diastolic function. In human cardiac fibroblasts, TIMP-1 protein and mRNA expressions were significantly increased by aldosterone through the glucocorticoid receptor/PI3K/Akt/nuclear factor-κB pathway. TIMP-1 small-interfering RNA significantly reduced aldosterone-induced collagen accumulation, and aldosterone did not alter the levels of collagen1a1 or matrix metalloproteinase-1 mRNA. The aldosterone-induced TIMP-1 expression was inversely related to matrix metalloproteinase-1 activity. Furthermore, in the animal model, the serum and cardiac levels of TIMP-1 were significantly elevated in the mice that received aldosterone infusion. This elevation was blocked by RU-486 but not by eplerenone, suggesting that the effect was through glucocorticoid receptors. In a long-term aldosterone infusion model, serum TIMP-1 was associated with serum aldosterone level, cardiac structure, and fibrosis. In conclusion, aldosterone induced TIMP-1 expression in vivo and in vitro. This increased TIMP-1 expression resulted in enhanced collagen accumulation via the suppression of matrix metalloproteinase-1 activity. PMID:27113051

  10. Inhibition of aldosterone synthase (CYP11B2) by torasemide prevents atrial fibrosis and atrial fibrillation in mice.

    PubMed

    Adam, Oliver; Zimmer, Christina; Hanke, Nina; Hartmann, Rolf W; Klemmer, Birgit; Böhm, Michael; Laufs, Ulrich

    2015-08-01

    Loop diuretics are used for fluid control in patients with heart failure. Furosemide and torasemide may exert differential effects on myocardial fibrosis. Here, we studied the effects of torasemide and furosemide on atrial fibrosis and remodeling during atrial fibrillation. In primary neonatal cardiac fibroblasts, torasemide (50μM, 24h) but not furosemide (50μM, 24h) reduced the expression of connective tissue growth factor (CTGF; 65±6%) and the pro-fibrotic miR-21 (44±23%), as well as the expression of lysyl oxidase (LOX; 57±8%), a regulator of collagen crosslinking. Mineralocorticoid receptor (MR) expression and activity were not altered. Torasemide but not furosemide inhibited human aldosterone synthase (CYP11B2) activity in transfected lung fibroblasts (V79MZ cells) by 75±1.8%. The selective CYP11B2 inhibitor SL242 mimicked the torasemide effects. Mice with cardiac overexpression of Rac1 GTPase (RacET), which develop atrial fibrosis and spontaneous AF with aging, were treated long-term (8months) with torasemide (10mg/kg/day), furosemide (40mg/kg/day) or vehicle. Treatment with torasemide but not furosemide prevented atrial fibrosis in RacET as well as the up-regulation of CTGF, LOX, and miR-2, whereas MR expression and activity remained unaffected. These effects correlated with a reduced prevalence of atrial fibrillation (33% RacET+Tora vs. 80% RacET). Torasemide but not furosemide inhibits CYP11B2 activity and reduces the expression of CTGF, LOX, and miR-21. These effects are associated with prevention of atrial fibrosis and a reduced prevalence of atrial fibrillation in mice. PMID:26047574

  11. New approaches to hyperkalemia in patients with indications for renin angiotensin aldosterone inhibitors: Considerations for trial design and regulatory approval.

    PubMed

    Zannad, Faiez; Rossignol, Patrick; Stough, Wendy Gattis; Epstein, Murray; Alonso Garcia, Maria de Los Angeles; Bakris, George L; Butler, Javed; Kosiborod, Mikhail; Berman, Lance; Mebazaa, Alexandre; Rasmussen, Henrik S; Ruilope, Luis M; Stockbridge, Norman; Thompson, Aliza; Wittes, Janet; Pitt, Bertram

    2016-08-01

    Hyperkalemia is a common clinical problem, especially in patients with chronic kidney disease, diabetes mellitus, or heart failure. Treatment with renin angiotensin aldosterone system inhibitors exacerbates the risk of hyperkalemia in these patients. Concern about hyperkalemia can result in the failure to initiate, suboptimal dosing, or discontinuation of renin angiotensin aldosterone system inhibitor therapy in patients; effective treatments for hyperkalemia might mitigate such undertreatment. New treatments for hyperkalemia in development may offer better efficacy, tolerability and safety profiles than do existing approved treatments. These compounds might enable more eligible patients to receive renin angiotensin aldosterone system inhibitor therapy or to receive renin angiotensin aldosterone system inhibitors at target doses. The evidence needed to support a treatment claim (reduction in serum potassium) differs from that needed to support a prevention claim (preventing hyperkalemia to allow renin angiotensin aldosterone system inhibitor treatment). Thus, several issues related to clinical trial design and drug development need to be considered. This paper summarizes and expands upon a discussion at the Global Cardiovascular Clinical Trialists 2014 Forum and examines methodologic considerations for trials of new potassium binders for the prevention and management of hyperkalemia in patients with renin angiotensin aldosterone system inhibitor indications. PMID:27140336

  12. Small-Conductance Ca2+-Activated Potassium Channels Negatively Regulate Aldosterone Secretion in Human Adrenocortical Cells.

    PubMed

    Yang, Tingting; Zhang, Hai-Liang; Liang, Qingnan; Shi, Yingtang; Mei, Yan-Ai; Barrett, Paula Q; Hu, Changlong

    2016-09-01

    Aldosterone, which plays a key role in maintaining water and electrolyte balance, is produced by zona glomerulosa cells of the adrenal cortex. Autonomous overproduction of aldosterone from zona glomerulosa cells causes primary hyperaldosteronism. Recent clinical studies have highlighted the pathological role of the KCNJ5 potassium channel in primary hyperaldosteronism. Our objective was to determine whether small-conductance Ca(2+)-activated potassium (SK) channels may also regulate aldosterone secretion in human adrenocortical cells. We found that apamin, the prototypic inhibitor of SK channels, decreased membrane voltage, raised intracellular Ca(2+) and dose dependently increased aldosterone secretion from human adrenocortical H295R cells. By contrast, 1-Ethyl-2-benzimidazolinone, an agonist of SK channels, antagonized apamin's action and decreased aldosterone secretion. Commensurate with an increase in aldosterone production, apamin increased mRNA expression of steroidogenic acute regulatory protein and aldosterone synthase that control the early and late rate-limiting steps in aldosterone biosynthesis, respectively. In addition, apamin increased angiotensin II-stimulated aldosterone secretion, whereas 1-Ethyl-2-benzimidazolinone suppressed both angiotensin II- and high K(+)-stimulated production of aldosterone in H295R cells. These findings were supported by apamin-modulation of basal and angiotensin II-stimulated aldosterone secretion from acutely prepared slices of human adrenals. We conclude that SK channel activity negatively regulates aldosterone secretion in human adrenocortical cells. Genetic association studies are necessary to determine whether mutations in SK channel subtype 2 genes may also drive aldosterone excess in primary hyperaldosteronism. PMID:27432863

  13. Undecaprenyl diphosphate synthase inhibitors: antibacterial drug leads.

    PubMed

    Sinko, William; Wang, Yang; Zhu, Wei; Zhang, Yonghui; Feixas, Ferran; Cox, Courtney L; Mitchell, Douglas A; Oldfield, Eric; McCammon, J Andrew

    2014-07-10

    There is a significant need for new antibiotics due to the rise in drug resistance. Drugs such as methicillin and vancomycin target bacterial cell wall biosynthesis, but methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococci (VRE) have now arisen and are of major concern. Inhibitors acting on new targets in cell wall biosynthesis are thus of particular interest since they might also restore sensitivity to existing drugs, and the cis-prenyl transferase undecaprenyl diphosphate synthase (UPPS), essential for lipid I, lipid II, and thus, peptidoglycan biosynthesis, is one such target. We used 12 UPPS crystal structures to validate virtual screening models and then assayed 100 virtual hits (from 450,000 compounds) against UPPS from S. aureus and Escherichia coli. The most promising inhibitors (IC50 ∼2 μM, Ki ∼300 nM) had activity against MRSA, Listeria monocytogenes, Bacillus anthracis, and a vancomycin-resistant Enterococcus sp. with MIC or IC50 values in the 0.25-4 μg/mL range. Moreover, one compound (1), a rhodanine with close structural similarity to the commercial diabetes drug epalrestat, exhibited good activity as well as a fractional inhibitory concentration index (FICI) of 0.1 with methicillin against the community-acquired MRSA USA300 strain, indicating strong synergism. PMID:24827744

  14. Discovery of DF-461, a Potent Squalene Synthase Inhibitor

    PubMed Central

    2013-01-01

    We report the development of a new trifluoromethyltriazolobenzoxazepine series of squalene synthase inhibitors. Structure–activity studies and pharmacokinetics optimization on this series led to the identification of compound 23 (DF-461), which exhibited potent squalene synthase inhibitory activity, high hepatic selectivity, excellent rat hepatic cholesterol synthesis inhibitory activity, and plasma lipid lowering efficacy in nonrodent repeated dose studies. PMID:24900587

  15. Inhibitors of glycogen synthase 3 kinase

    DOEpatents

    Schultz, Peter; Ring, David B.; Harrison, Stephen D.; Bray, Andrew M.

    2006-05-30

    Compounds of formula 1: ##STR00001## wherein R.sub.1 is alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heteroaralkyl, substituted with 0 3 substituents selected from lower alkyl, halo, hydroxy, lower alkoxy, amino, lower alkyl-amino, and nitro; R.sub.2 is hydroxy, amino, or lower alkoxy; R.sub.3 is H, lower alkyl, lower acyl, lower alkoxy-acyl, or amino-acyl; R.sub.4 is H or lower alkyl; and pharmaceutically acceptable salts and esters thereof; are effective inhibitors of GSK3.

  16. Inhibitors of glycogen synthase 3 kinase

    DOEpatents

    Schultz, Peter; Ring, David B.; Harrison, Stephen D.; Bray, Andrew M.

    2000-01-01

    Compounds of formula 1: ##STR1## wherein R.sub.1 is alkyl, cycloalkyl, aryl, aralkyl, heteroaryl, or heteroaralkyl, substituted with 0-3 substituents selected from lower alkyl, halo, hydroxy, lower alkoxy, amino, lower alkyl-amino, and nitro; R.sub.2 is hydroxy, amino, or lower alkoxy; R.sub.3 is H, lower alkyl, lower acyl, lower alkoxy-acyl, or amnino-acyl; R.sub.4 is H or lower alkyl; and pharmaceutically acceptable salts and esters thereof; are effective inhibitors of GSK3.

  17. Inhibitors of nitric oxide synthase in inflammatory arthritis.

    PubMed

    Boughton-Smith, N K; Tinker, A C

    1998-07-01

    There is considerable evidence that excessive nitric oxide (NO) synthesized from L-arginine by inducible nitric oxide synthase (iNOS) plays an important pathological role in inflammatory arthritis. Since NO synthesized by constitutive isoforms of NOS has a physiological role, a great deal of activity has been directed at identifying inhibitors of NOS that are selective for the induced isoform. The major chemical areas that have been described so far in the search for such selective iNOS inhibitors and the activity of some of these compounds in animal models of arthritis are reviewed. PMID:18465556

  18. Nitroaromatic amino acids as inhibitors of neuronal nitric oxide synthase.

    PubMed

    Cowart, M; Kowaluk, E A; Daanen, J F; Kohlhaas, K L; Alexander, K M; Wagenaar, F L; Kerwin, J F

    1998-07-01

    Nitric oxide (NO.) is an important biomodulator of many physiological processes. The inhibition of inappropriate production of NO. by the isoforms of nitric oxide synthase (NOS) has been proposed as a therapeutic approach for the treatment of stroke, inflammation, and other processes. In this study, certain 2-nitroaryl-substituted amino acid analogues were discovered to inhibit NOS. Analogues bearing a 5-methyl substituent on the aromatic ring demonstrated maximal inhibitory potency. For two selected inhibitors, investigation of the kinetics of the enzyme showed the inhibition to be competitive with l-arginine. Additionally, functional NOS inhibition in tissue preparations was demonstrated. PMID:9651169

  19. Structure-Based Discovery of Inhibitors of Thymidylate Synthase

    NASA Astrophysics Data System (ADS)

    Shoichet, Brian K.; Stroud, Robert M.; Santi, Daniel V.; Kuntz, Irwin D.; Perry, Kathy M.

    1993-03-01

    A molecular docking computer program (DOCK) was used to screen the Fine Chemical Directory, a database of commercially available compounds, for molecules that are complementary to thymidylate synthase (TS), a chemotherapeutic target. Besides retrieving the substrate and several known inhibitors, DOCK proposed putative inhibitors previously unknown to bind to the enzyme. Three of these compounds inhibited Lactobacillus caser TS at submillimolar concentrations. One of these inhibitors, sulisobenzone, crystallized with TS in two configurations that differed from the DOCK-favored geometry: a counterion was bound in the substrate site, which resulted in a 6 to 9 angstrom displacement of the inhibitor. The structure of the complexes suggested another binding region in the active site that could be exploited. This region was probed with molecules sterically similar to sulisobenzone, which led to the identification of a family of phenolphthalein analogs that inhibit TS in the 1 to 30 micromolar range. These inhibitors do not resemble the substrates of the enzyme. A crystal structure of phenolphthalein with TS shows that it binds in the target site in a configuration that resembles the one suggested by DOCK.

  20. Structure-Based Design of Bacterial Nitric Oxide Synthase Inhibitors

    PubMed Central

    2015-01-01

    Inhibition of bacterial nitric oxide synthase (bNOS) has the potential to improve the efficacy of antimicrobials used to treat infections by Gram-positive pathogens Staphylococcus aureus and Bacillus anthracis. However, inhibitor specificity toward bNOS over the mammalian NOS (mNOS) isoforms remains a challenge because of the near identical NOS active sites. One key structural difference between the NOS isoforms is the amino acid composition of the pterin cofactor binding site that is adjacent to the NOS active site. Previously, we demonstrated that a NOS inhibitor targeting both the active and pterin sites was potent and functioned as an antimicrobial (Holden, , Proc. Natl. Acad. Sci. U.S.A.2013, 110, 1812724145412). Here we present additional crystal structures, binding analyses, and bacterial killing studies of inhibitors that target both the active and pterin sites of a bNOS and function as antimicrobials. Together, these data provide a framework for continued development of bNOS inhibitors, as each molecule represents an excellent chemical scaffold for the design of isoform selective bNOS inhibitors. PMID:25522110

  1. Structural Studies of Pterin-Based Inhibitors of Dihydropteroate Synthase

    SciTech Connect

    Hevener, Kirk E.; Yun, Mi-Kyung; Qi, Jianjun; Kerr, Iain D.; Babaoglu, Kerim; Hurdle, Julian G.; Balakrishna, Kanya; White, Stephan W.; Lee, Richard E.

    2010-01-12

    Dihydropteroate synthase (DHPS) is a key enzyme in bacterial folate synthesis and the target of the sulfonamide class of antibacterials. Resistance and toxicities associated with sulfonamides have led to a decrease in their clinical use. Compounds that bind to the pterin binding site of DHPS, as opposed to the p-amino benzoic acid (pABA) binding site targeted by the sulfonamide agents, are anticipated to bypass sulfonamide resistance. To identify such inhibitors and map the pterin binding pocket, we have performed virtual screening, synthetic, and structural studies using Bacillus anthracis DHPS. Several compounds with inhibitory activity have been identified, and crystal structures have been determined that show how the compounds engage the pterin site. The structural studies identify the key binding elements and have been used to generate a structure-activity based pharmacophore map that will facilitate the development of the next generation of DHPS inhibitors which specifically target the pterin site.

  2. Structural Studies of Pterin-Based Inhibitors of Dihydropteroate Synthase

    PubMed Central

    Hevener, Kirk E.; Yun, Mi-Kyung; Qi, Jianjun; Kerr, Iain D.; Babaoglu, Kerim; Hurdle, Julian G.; Balakrishna, Kanya; White, Stephen W.; Lee, Richard E.

    2009-01-01

    Dihydropteroate synthase (DHPS) is a key enzyme in bacterial folate synthesis and the target of the sulfonamide class of antibacterials. Resistance and toxicities associated with sulfonamides have led to a decrease in their clinical use. Compounds that bind to the pterin binding site of DHPS, as opposed to the p-amino benzoic acid (pABA) binding site targeted by the sulfonamide agents, are anticipated to bypass sulfonamide resistance. To identify such inhibitors and map the pterin binding pocket, we have performed virtual screening, synthetic, and structural studies using Bacillus anthracis DHPS. Several compounds with inhibitory activity have been identified, and crystal structures have been determined that show how the compounds engage the pterin site. The structural studies identify the key binding elements and have been used to generate a structure-activity based pharmacophore map that will facilitate the development of the next generation of DHPS inhibitors which specifically target the pterin site. PMID:19899766

  3. Inhibitors to Polyhydroxyalkanoate (PHA) Synthases: Synthesis, Molecular Docking, and Implications

    PubMed Central

    Cao, Ruikai; Maurmann, Leila; Li, Ping

    2015-01-01

    Polyhydroxyalkanoate (PHA) synthases (PhaCs) catalyze the formation of biodegradable PHAs that are considered as an ideal alternative to nonbiodegradable synthetic plastics. However, study of PhaC has been challenging because the rate of PHA chain elongation is much faster than that of initiation. This difficulty along with lack of a structure has become the main hurdle to understand and engineer PhaCs for economical PHA production. Here we reported the synthesis of two carbadethia CoA analogs, sT-CH2-CoA 26a and sTet-CH2-CoA 26b as well as sT-aldehyde 29 as new PhaC inhibitors. Study of these analogs with PhaECAv revealed that 26a/b and 29 are competitive and mixed inhibitors, respectively. It was observed that CoA moiety and PHA chain extension can increase binding affinity, which is consistent with the docking study. Estimation from Kic of 26a/b predicts that a CoA analog attached with an octameric-HB chain may facilitate the formation of a kinetically well-behaved synthase. PMID:25394180

  4. Inhibitors of polyhydroxyalkanoate (PHA) synthases: synthesis, molecular docking, and implications.

    PubMed

    Zhang, Wei; Chen, Chao; Cao, Ruikai; Maurmann, Leila; Li, Ping

    2015-01-01

    Polyhydroxyalkanoate (PHA) synthases (PhaCs) catalyze the formation of biodegradable PHAs that are considered to be ideal alternatives to non-biodegradable synthetic plastics. However, study of PhaCs has been challenging because the rate of PHA chain elongation is much faster than that of initiation. This difficulty, along with lack of a crystal structure, has become the main hurdle to understanding and engineering PhaCs for economical PHA production. Here we report the synthesis of two carbadethia CoA analogues--sT-CH2-CoA (26 a) and sTet-CH2-CoA (26 b)--as well as sT-aldehyde (saturated trimer aldehyde, 29), as new PhaC inhibitors. Study of these analogues with PhaECAv revealed that 26 a/b and 29 are competitive and mixed inhibitors, respectively. Both the CoA moiety and extension of PHA chain will increase binding affinity; this is consistent with our docking study. Estimation of the Kic values of 26 a and 26 b predicts that a CoA analogue incorporating an octameric hydroxybutanoate (HB) chain might facilitate the formation of a kinetically well-behaved synthase. PMID:25394180

  5. Glycogen synthase kinase-3 inhibitors: Rescuers of cognitive impairments

    PubMed Central

    King, Margaret K.; Pardo, Marta; Cheng, Yuyan; Downey, Kimberlee; Jope, Richard S.; Beurel, Eléonore

    2013-01-01

    Impairment of cognitive processes is a devastating outcome of many diseases, injuries, and drugs affecting the central nervous system (CNS). Most often, very little can be done by available therapeutic interventions to improve cognitive functions. Here we review evidence that inhibition of glycogen synthase kinase-3 (GSK3) ameliorates cognitive deficits in a wide variety of animal models of CNS diseases, including Alzheimer's disease, Fragile X syndrome, Down syndrome, Parkinson's disease, spinocerebellar ataxia type 1, traumatic brain injury, and others. GSK3 inhibitors also improve cognition following impairments caused by therapeutic interventions, such as cranial irradiation for brain tumors. These findings demonstrate that GSK3 inhibitors are able to ameliorate cognitive impairments caused by a diverse array of diseases, injury, and treatments. The improvements in impaired cognition instilled by administration of GSK3 inhibitors appear to involve a variety of different mechanisms, such as supporting long-term potentiation and diminishing long-term depression, promotion of neurogenesis, reduction of inflammation, and increasing a number of neuroprotective mechanisms. The potential for GSK3 inhibitors to repair cognitive deficits associated with many conditions warrants further investigation of their potential for therapeutic interventions, particularly considering the current dearth of treatments available to reduce loss of cognitive functions. PMID:23916593

  6. A systematic review on randomized control trials on rennin angiotensin aldosterone system inhibitors role in managing hypertension among hemodialysis patients.

    PubMed

    Aftab, Raja Ahsan; Khan, Amer Hayat; Adnan, Azreen Syazril; Jannah, Nurul

    2016-01-01

    Randomized control trials (RCTs) are considered as most rigors way of determining the cause-effect relationship of a treatment and outcome. Activation of rennin angiotensin aldosterone system (RAAS) is an important contributor to hypertension in hemodialysis patients. The prevalence of hypertension in hemodialysis patients varies from 60% to 80% and hypertension management alone with conventional hemodialysis is insufficient. Hence, the current review was aimed to investigate the effect of RAAS inhibitors in managing hypertension among hemodialysis patients in a randomized control trial. Using PUBMED and EMBASE databases, randomized control trial with primary or secondary outcomes related to the effect of RAAS inhibitors on blood pressure among hemodialysis patients were included for analysis. The current review also assessed the quality of reporting of RCT. A total of eight RCT met inclusion criteria for current review. According to modified jaded scale, one (12.5%) study scored four points for quality reporting, whereas two (25%) studies scored one point that was the least score. The mean score for all included studies was 2.25. Six (75%) of the eight RCT included, involved ARB in hypertension management among hemodialysis patients, whereas two (25%) studies involved angiotensin-converting enzyme (ACE) inhibitors. Of the siz RCT involving ARB, two (33.3%) RCT also included ACE inhibitors comparison group. Altogether six (75%) studies report a reduction in blood pressure with the use of RAAS inhibitors compared to control group; however, of the six studies, two (33.3%) reported that the reduction in blood pressure was not significant. Whereas, two (25%) studies reported no reduction in blood pressure compared to the control group. The findings from current review do not indicate a clear pattern for a role of RAAS inhibitors for hypertension control among hemodialysis patients. PMID:26853680

  7. A new motif for inhibitors of geranylgeranyl diphosphate synthase.

    PubMed

    Foust, Benjamin J; Allen, Cheryl; Holstein, Sarah A; Wiemer, David F

    2016-08-15

    The enzyme geranylgeranyl diphosphate synthase (GGDPS) is believed to receive the substrate farnesyl diphosphate through one lipophilic channel and release the product geranylgeranyl diphosphate through another. Bisphosphonates with two isoprenoid chains positioned on the α-carbon have proven to be effective inhibitors of this enzyme. Now a new motif has been prepared with one isoprenoid chain on the α-carbon, a second included as a phosphonate ester, and the potential for a third at the α-carbon. The pivaloyloxymethyl prodrugs of several compounds based on this motif have been prepared and the resulting compounds have been tested for their ability to disrupt protein geranylgeranylation and induce cytotoxicity in myeloma cells. The initial biological studies reveal activity consistent with GGDPS inhibition, and demonstrate a structure-function relationship which is dependent on the nature of the alkyl group at the α-carbon. PMID:27338660

  8. Treatment with patiromer decreases aldosterone in patients with chronic kidney disease and hyperkalemia on renin-angiotensin system inhibitors.

    PubMed

    Weir, Matthew R; Bakris, George L; Gross, Coleman; Mayo, Martha R; Garza, Dahlia; Stasiv, Yuri; Yuan, Jinwei; Berman, Lance; Williams, Gordon H

    2016-09-01

    Elevated serum aldosterone can be vasculotoxic and facilitate cardiorenal damage. Renin-angiotensin system inhibitors reduce serum aldosterone levels and/or block its effects but can cause hyperkalemia. Patiromer, a nonabsorbed potassium binder, decreases serum potassium in patients with chronic kidney disease on renin-angiotensin system inhibitors. Here we examined the effect of patiromer treatment on serum aldosterone, blood pressure, and albuminuria in patients with chronic kidney disease on renin-angiotensin system inhibitors with hyperkalemia (serum potassium 5.1-6.5 mEq/l). We analyzed data from the phase 3 OPAL-HK study (4-week initial treatment phase of 243 patients; 8-week randomized withdrawal phase of 107 patients). In the treatment phase, the (mean ± standard error) serum potassium was decreased concordantly with the serum aldosterone (-1.99 ± 0.51 ng/dl), systolic/diastolic blood pressure (-5.64 ± 1.04 mm Hg/-3.84 ± 0.69 mm Hg), and albumin-to-creatinine ratio (-203.7 ± 54.7 mg/g), all in a statistically significant manner. The change in the plasma renin activity (-0.44 ± 0.63 μg/l/hr) was not significant. In the withdrawal phase, mean aldosterone levels were sustained with patiromer (+0.23 ± 1.07 ng/dl) and significantly increased with placebo (+2.78 ± 1.25 ng/dl). Patients on patiromer had significant reductions in mean systolic/diastolic blood pressure (-6.70 ± 1.59/-2.15 ± 1.06 mm Hg), whereas those on placebo did not (-1.21 ± 1.89 mm Hg/+1.72 ± 1.26 mm Hg). Significant changes in plasma renin activity were found only in the placebo group (-3.90 ± 1.41 μg/l/hr). Thus, patiromer reduced serum potassium and aldosterone levels independent of plasma renin activity in patients with chronic kidney disease and hyperkalemia on renin-angiotensin system inhibitors. PMID:27350174

  9. Relationship of Genetic Polymorphisms of Aldosterone Synthase Gene Cytochrome P450 11B2 and Mineralocorticoid Receptors with Coronary Artery Disease in Taiwan

    PubMed Central

    Chou, Chi-Hung; Ueng, Kwo-Chang; Yang, Shun-Fa; Wu, Chih-Hsien; Wang, Po-Hui

    2016-01-01

    The aldosterone synthase gene, cytochrome P450 11B2 (CYP11B2), and mineralocorticoid receptor (MR) genes have been reported to be associated with coronary artery disease (CAD). In this study, we investigated the association of single nucleotide polymorphisms (SNPs) of CYP11B2 (CYP11B2 T-344C) and MR (MR C3514G and MR C4582A) with CAD in Taiwanese. Six hundred and nine unrelated male and female subjects who received elective coronary angiography were recruited from Chung Shan Medical University Hospital. The enrolled subjects were those who had a positive noninvasive test. CYP11B2 T-344C, MR C3514G and MR C4582A were determined by polymerase chain reaction-restriction fragment length polymorphism. We found that women with CYP11B2 C/C had a higher risk of developing CAD. However, there were no significant differences in the genotype distributions of MR C3514G and MR C4582A between the women with and without CAD. In multivariate analysis, CYP11B2 T-344C was most significantly associated with CAD in Taiwanese women. In conclusions, CYP11B2 C/C was more significantly associated with the development of CAD than diabetes mellitus or hypertension. This implies that CYP11B2 C/C plays a more important role than some conventional risk factors in the development of CAD in Taiwanese women. PMID:26941570

  10. Isolation and structural determination of squalene synthase inhibitor from Prunus mume fruit.

    PubMed

    Choi, Sung-Won; Hur, Nam-Yoon; Ahn, Soon-Cheol; Kim, Dong-Seob; Lee, Jae-Kwon; Kim, Dae-Ok; Park, Seung-Kook; Kim, Byung-Yong; Baik, Moo-Yeol

    2007-12-01

    Squalene synthase plays an important role in the cholesterol biosynthetic pathway. Inhibiting this enzyme in hypercholesterolemia can lower not only plasma cholesterol but also plasma triglyceride levels. A squalene synthase inhibitor was screened from Prunus mume fruit, and then purified via sequential processes of ethanol extraction, HP-20 column chromatography, ethyl acetate extraction, silica gel column chromatography, and crystallization. The squalene synthase inhibitor was identified as chlorogenic acid with a molecular mass of 354 Da and a molecular formula of C16H18O9 based on UV spectrophotometry, 1H and 13C NMRs, and mass spectrometry. Chlorogenic acid inhibited the squalene synthase of pig liver with an IC50 level of 100 nM. Since chlorogenic acid was an effective inhibitor against the squalene synthase of an animal source, it may be a potential therapeutic agent for hypercholesterolemia. PMID:18167444

  11. Use of nitric oxide synthase inhibitors for the treatment of inflammatory disease and pain.

    PubMed

    Cheshire, D R

    2001-07-01

    This article reviews the recent literature on selective inhibitors of nitric oxide synthase (NOS) between 1999 and the first quarter of 2001. The introduction highlights the major therapeutic objectives for NOS inhibitors, including rheumatoid arthritis (RA), osteoarthritis (OA) and pain. The review attempts to cover the structural diversity of small molecule NOS inhibitors currently being explored in the pharmaceutical and academic communities. PMID:15995936

  12. Inflammatory markers in paroxysmal atrial fibrillation and the protective role of renin-angiotensin-aldosterone system inhibitors

    PubMed Central

    ROŞIANU, ŞTEFAN HORIA; ROŞIANU, ADELA-NICOLETA; ALDICA, MIHAI; CĂPÂLNEANU, RADU; BUZOIANU, ANCA DANA

    2013-01-01

    Background Experimental and clinical studies have shown the importance of inflammation in the pathophysiology of atrial fibrillation (AF). The renin-angiotensin-aldosterone system (RAAS) may play an important role in the pathogenesis of AF in correlation with the inflammatory process. RAAS inhibition may have important therapeutic value in limiting AF. The aim of this study was the correlation between inflammatory markers and recurrent episodes of AF in patients with known paroxysmal atrial fibrillation, with and without treatment with RAAS inhibitors. Methods and results We studied 82 patients with paroxysmal AF recorded at “Niculae Stancioiu” Heart Institute Cluj-Napoca, divided into two groups: group A treated with angiotensin converting enzyme (ACE) inhibitors or angiotensin receptor blockers (ARB) and group B without this medication. All patients underwent clinical examination, ECG, echocardiography and determination of plasma levels of inflammatory markers represented by high sensitivity C-reactive protein (hs-CRP) and interleukin 6 (IL-6). In the group treated with ACE inhibitors/ARBs, AF burden was significantly lower than in patients without treatment. We obtained a strong positive correlation between blood levels of high-sensitivity CRP and those of IL-6 (r=0.64, p<0.001), the number of yearly AF episodes (r=0.570, p<0.001), LA diameter (r=0.5, p<0.001) and LA volume (r=0.5, p<0.001). We found moderate positive correlations between blood levels of IL-6 and LA diameter (r=0.305, p=0.01), LA volume (r=0.314, p=0.01), the number of yearly AF episodes (r=0.489, p<0.001), the total number of AF episodes (r=0.304, p<0.001), BMI (r=0.473, p<0.001), LA area (r=0.458, p<0.001), LA area index (r=0.334, p=0.007) and LA volume index (r=0.304, p=0.01). The number of yearly AF episodes and BMI values influenced IL-6 blood levels (t=3.46, p=0.001, respectively t=2.17, p=0.03). Conclusions Inflammation is present in patients with AF, with or without treatment with

  13. Total synthesis of the squalene synthase inhibitor zaragozic acid C.

    PubMed

    Nakamura, Seiichi

    2005-01-01

    Zaragozic acids and squalestatins were documented by Merck, Glaxo, and Tokyo Noko University/Mitsubishi Kasei Corporation as part of a program aimed at identifying novel inhibitors of squalene synthase, as well as farnesyl transferase. These natural products have attracted considerable attention from numerous synthetic chemists because of their therapeutic potential and novel architecture. This review highlights our total syntheses of zaragozic acid C by two convergent strategies. The key steps in our first-generation synthesis involve 1) simultaneous creation of the C4 and C5 quaternary stereocenters through the Sn(OTf)2-promoted aldol coupling reaction between the alpha-keto ester and silyl ketene thioacetal derived from L- and D-tartaric acids, respectively; and 2) construction of the bicyclic core structure via acid-catalyzed internal ketalization under kinetically controlled conditions. The second-generation strategy relies on a tandem carbonyl ylide formation/1,3-dipolar cycloaddition approach and features elongation of the C1 alkyl side chain through an olefin cross-metathesis as well as high convergency and flexibility. PMID:15635219

  14. Cyclopentanedi- and tricarboxylic acids as squalene synthase inhibitors: syntheses and evaluation.

    PubMed

    Shen, W; Garvey, D S; Cohen, J; Stein, H; Rosenberg, S H

    1998-04-21

    Based on earlier lead squalene synthase inhibitor A-87049 (3) and zaragozic acids, a series of cyclopentanedi- and tricarboxylic acids were synthesized and evaluated against the enzyme. Some exhibited good potency and SAR revealed the importance of conformation and substitution pattern of these synthetic inhibitors. PMID:9871507

  15. Investigation of potential glycogen synthase kinase 3 inhibitors using pharmacophore mapping and virtual screening.

    PubMed

    Dessalew, Nigus; Bharatam, Prasad V

    2006-09-01

    Glycogen synthase kinase-3 is a serine/threonine kinase that has attracted significant drug discovery attention in recent years. To investigate the identification of new potential glycogen synthase kinase-3 inhibitors, a pharmacophore mapping study was carried out using a set of 21 structurally diverse glycogen synthase kinase-3 inhibitors. A hypothesis containing four features: two hydrophobic, one hydrogen bond donor and another hydrogen bond acceptor was found to be the best from the 10 common feature hypotheses produced by HipHop module of Catalyst. The best hypothesis has a high cost of 156.592 and higher best fit values were obtained for the 21 inhibitors using this best hypothesis than the other HipHop hypotheses. The best hypothesis was then used to screen electronically the NCI2000 database. The hits obtained were docked into glycogen synthase kinase-3beta active site. A total of five novel potential leads were proposed after: (i) visual examination of how well they dock into the glycogen synthase kinase-3beta-binding site, (ii) comparative analysis of their FlexX, G-Score, PMF-Score, ChemScore and D-Scores values, (iii) comparison of their best fit value with the known inhibitors and (iv) examination of the how the hits retain interactions with the important amino acid residues of glycogen synthase kinase-3beta-binding site. PMID:17062013

  16. Aldosterone: from biosynthesis to non-genomic action onto the proteome.

    PubMed

    Zöllner, Susanne; Hwang, Kyung Hoon; Wilzewski, Britta; Carapito, Christine; Leize-Wagner, Emmanuelle; Van Dorsselaer, Alain; Bernhardt, Rita

    2008-10-01

    An increased aldosterone concentration can lead to a progression of heart diseases and to myocardial fibrosis. These fatal processes can be prevented by e.g. inhibiting the mineralocorticoid receptor (MR), which is nowadays part of a commonly applied standard therapy. Moreover, selective inhibition of aldosterone synthase (CYP11B2) is a straightforward goal whereby CYP11B1, a key enzyme in glucocorticoid biosynthesis exhibiting a high structure identity with CYP11B2 should not be inhibited. Therefore, effective test systems have been developed and rather potent and selective CYP11B2 compounds like SIAS-1 have been identified by our group. In addition to finding new inhibitors, we investigated which proteins are directly influenced by aldosterone focussing on non-genomic effects. Schizosaccharomyces pombe was chosen as a model organism, since this yeast does not contain nuclear steroid receptors, but many genes and regulatory mechanisms that are close to those of mammals. Besides creating a reference map for this organism, protein spots affected by aldosterone as well as deoxycorticosterone (DOC) and corticosterone have been identified. In case of aldosterone, a regulatory effect of proteins that are connected with structural proteins, signal cascades, osmoregulation and calcium pathway as well as to general metabolism have been discovered. DOC causes overlapping but also different effects compared with aldosterone. As shown exemplarily for GAPDH, the aldosterone-mediated effects in S. pombe can also be verified in mammalian cells. These and further investigations contribute to a deeper understanding of so-called non-genomic aldosterone effects. PMID:18280527

  17. Laboratory investigation of primary aldosteronism.

    PubMed

    Stowasser, Michael; Taylor, Paul J; Pimenta, Eduardo; Ahmed, Ashraf H Al-Asaly; Gordon, Richard D

    2010-05-01

    Availability and wider application of the plasma aldosterone/renin ratio (ARR) as a screening test for primary aldosteronism (PA) has led to the recognition that PA is the most common potentially curable and specifically treatable form of hypertension, possibly accounting for as many as 5-13% of patients. Aldosterone excess also has adverse cardiovascular consequences that go above and beyond hypertension development. These findings support the concept that PA plays an important role in cardiovascular disease states and should be systematically sought and specifically treated, and have led to the development of a US Endocrine Society clinical guideline for the detection, diagnosis and management of this condition. Reliable detection requires that interfering factors (including medications known to alter the ratio) are controlled before ARR measurement (or their effects taken into account), and reliable methods such as fludrocortisone suppression testing are used to confirm PA. Because computed tomography frequently misses aldosterone-producing adenomas yet demonstrates non-functioning nodules, adrenal venous sampling is the only dependable way to differentiate unilateral (surgically correctable) from bilateral (usually treated with aldosterone antagonist medications) forms of PA. For the glucocorticoid-remediable form of PA (familial hyperaldosteronism type I), genetic testing for the causative 'hybrid' 11beta-hydroxylase/aldosterone synthase gene has greatly facilitated detection. Laboratory assessment (including suppression testing post-operatively, and renin measurement during treatment with aldosterone antagonist medications) can assist in assessing therapeutic responses and in guiding ongoing management. Development of new, highly reliable high-throughput mass spectrometric methods for measuring aldosterone and renin should further enhance detection and reliability of diagnostic workup for PA. PMID:20498828

  18. Nω-NITRO-Nω’-SUBSTITUTED GUANIDINES: A SIMPLE CLASS OF NITRIC OXIDE SYNTHASE INHIBITORS

    PubMed Central

    Guillon, Christophe D.; Wisnoski, David D.; Saxena, Jaya; Heindel, Ned D.; Heck, Diane E.; Wolff, Donald J.; Laskin, Jeffrey D.

    2014-01-01

    A series of Nω-nitro-Nω’-substituted guanidines has been prepared as potential inhibitors of the human Nitric Oxide Synthase (NOS) isoforms. The reported utility of aminoguanidine and nitroarginine in iNOS inhibition points to a potential similar utility for analogs of nitro-guanidine. The compound library was tested against the three isoforms of Nitric Oxide Synthase (eNOS, iNOS and nNOS). Several candidates showed excellent activity and good selectivity for nNOS. One particular compound even demonstrated good selectivity for iNOS. The potential usefulness of such selective inhibitors is discussed. PMID:25360396

  19. Reviewing Ligand-Based Rational Drug Design: The Search for an ATP Synthase Inhibitor

    PubMed Central

    Lee, Chia-Hsien; Huang, Hsuan-Cheng; Juan, Hsueh-Fen

    2011-01-01

    Following major advances in the field of medicinal chemistry, novel drugs can now be designed systematically, instead of relying on old trial and error approaches. Current drug design strategies can be classified as being either ligand- or structure-based depending on the design process. In this paper, by describing the search for an ATP synthase inhibitor, we review two frequently used approaches in ligand-based drug design: The pharmacophore model and the quantitative structure-activity relationship (QSAR) method. Moreover, since ATP synthase ligands are potentially useful drugs in cancer therapy, pharmacophore models were constructed to pave the way for novel inhibitor designs. PMID:21954360

  20. Chloropropionyl-CoA: a mechanism-based inhibitor of HMG-CoA synthase and fatty acid synthase

    SciTech Connect

    Miziorko, H.M.; Ahmad, F.; Behnke, C.E.

    1986-05-01

    Recent work on the mechanisms of inactivation of HMG-CoA synthase and fatty acid synthase by chloropropionyl-CoA (Cl-prop-CoA) suggests that this analog is a mechanism-based (suicide) inhibitor; the acyl group is enzymatically converted to an acrylyl derivative prior to alkylation of the target proteins. When Cl-(/sup 3/H)prop-CoA is incubated with the target enzymes, /sup 3/H/sub 2/O is produced concomitantly with enzyme inactivation; this suggests that deprotonation and chloride elimination to form an acrylyl moiety occurs. Difficulty in cleanly synthesizing acrylyl-CoA complicates direct demonstration of the intermediacy of this species. However, synthesis of a functionally equivalent reactive substrate analog, S-acrylyl-N-acetylcysteamine has been accomplished. This analog irreversibly inhibits both HMG-CoA synthase and fatty acid synthase in a site directed fashion. Concentrations required for effective inhibition (K/sub i/ values of 1.9 mM and 3.6 mM, respectively) are much higher than observed with Cl-prop-CoA. Maximal rates of inactivation (as vertical bar ..-->.. infinity) are comparable to those measured with Cl-prop-CoA, indicating that an acrylyl derivative is kinetically competent to function as an intermediate, as required if Cl-prop-CoA is a mechanism-based inhibitor. S-acrylyl-N-acetylcysteamine also inactivates HMG-CoA lyase. In this case, kinetic studies indicate that a bimolecular process is involved (k/sub 2/ = 86.7M/sup -1/min/sup -1/ at 30/sup 0/, pH 7.0).

  1. Improved Synthesis of Chiral Pyrrolidine Inhibitors and Their Binding Properties to Neuronal Nitric Oxide Synthase

    PubMed Central

    Xue, Fengtian; Kraus, James M.; Labby, Kristin Jansen; Ji, Haitao; Mataka, Jan; Xia, Guoyao; Li, Huiying; Delker, Silvia L.; Roman, Linda J.; Martásek, Pavel; Poulos, Thomas L.; Silverman, Richard B.

    2011-01-01

    We report an efficient synthetic route to chiral pyrrolidine inhibitors of neuronal nitric oxide synthase (nNOS) and crystal structures of the inhibitors bound to nNOS and to endothelial NOS. The new route enables versatile structure activity relationship studies on the pyrrolidine-based scaffold, which can be beneficial for further development of nNOS inhibitors. The X-ray crystal structures of three new fluorine-containing inhibitors bound to nNOS provide insights into the effect of the fluorine atoms on binding. PMID:21809851

  2. Aldosterone blood test

    MedlinePlus

    ... hypotension) Aldosterone is a hormone released by the adrenal glands . It helps the body regulate blood pressure. Aldosterone ... may be due to Bartter syndrome (extremely rare) Adrenal glands release too much aldosterone hormone ( primary hyperaldosteronism - usually ...

  3. Antagonism screen for inhibitors of bacterial cell wall biogenesis uncovers an inhibitor of undecaprenyl diphosphate synthase

    PubMed Central

    Farha, Maya A.; Czarny, Tomasz L.; Myers, Cullen L.; Worrall, Liam J.; French, Shawn; Conrady, Deborah G.; Wang, Yang; Oldfield, Eric; Strynadka, Natalie C. J.; Brown, Eric D.

    2015-01-01

    Drug combinations are valuable tools for studying biological systems. Although much attention has been given to synergistic interactions in revealing connections between cellular processes, antagonistic interactions can also have tremendous value in elucidating genetic networks and mechanisms of drug action. Here, we exploit the power of antagonism in a high-throughput screen for molecules that suppress the activity of targocil, an inhibitor of the wall teichoic acid (WTA) flippase in Staphylococcus aureus. Well-characterized antagonism within the WTA biosynthetic pathway indicated that early steps would be sensitive to this screen; however, broader interactions with cell wall biogenesis components suggested that it might capture additional targets. A chemical screening effort using this approach identified clomiphene, a widely used fertility drug, as one such compound. Mechanistic characterization revealed the target was the undecaprenyl diphosphate synthase, an enzyme that catalyzes the synthesis of a polyisoprenoid essential for both peptidoglycan and WTA synthesis. The work sheds light on mechanisms contributing to the observed suppressive interactions of clomiphene and in turn reveals aspects of the biology that underlie cell wall synthesis in S. aureus. Further, this effort highlights the utility of antagonistic interactions both in high-throughput screening and in compound mode of action studies. Importantly, clomiphene represents a lead for antibacterial drug discovery. PMID:26283394

  4. MULTI-ANALYTE CHEMISTRY METHODS FOR PESTICIDES WHICH ARE ACETOLACTATE SYNTHASE (ALS) INHIBITORS IN SOIL

    EPA Science Inventory

    A joint EPA/state/industry working group has developed several multi-analyte methods to analyze soils for low ppb (parts per billion) levels of herbicides (such as sulfonylureas, imidazolinones, and sulfonamides) that are acetolactate synthase (ALS) inhibitors and may cause phyto...

  5. Modulation of Alternaria infectoria Cell Wall Chitin and Glucan Synthesis by Cell Wall Synthase Inhibitors

    PubMed Central

    Fernandes, Chantal; Anjos, Jorge; Walker, Louise A.; Silva, Branca M. A.; Cortes, Luísa; Mota, Marta; Munro, Carol A.; Gow, Neil A. R.

    2014-01-01

    The present work reports the effects of caspofungin, a β-1,3-glucan synthase inhibitor, and nikkomycin Z, an inhibitor of chitin synthases, on two strains of Alternaria infectoria, a melanized fungus involved in opportunistic human infections and respiratory allergies. One of the strains tested, IMF006, bore phenotypic traits that conferred advantages in resisting antifungal treatment. First, the resting cell wall chitin content was higher and in response to caspofungin, the chitin level remained constant. In the other strain, IMF001, the chitin content increased upon caspofungin treatment to values similar to basal IMF006 levels. Moreover, upon caspofungin treatment, the FKS1 gene was upregulated in IMF006 and downregulated in IMF001. In addition, the resting β-glucan content was also different in both strains, with higher levels in IMF001 than in IMF006. However, this did not provide any advantage with respect to echinocandin resistance. We identified eight different chitin synthase genes and studied relative gene expression when the fungus was exposed to the antifungals under study. In both strains, exposure to caspofungin and nikkomycin Z led to modulation of the expression of class V and VII chitin synthase genes, suggesting its importance in the robustness of A. infectoria. The pattern of A. infectoria phagocytosis and activation of murine macrophages by spores was not affected by caspofungin. Monotherapy with nikkomycin Z and caspofungin provided only fungistatic inhibition, while a combination of both led to fungal cell lysis, revealing a strong synergistic action between the chitin synthase inhibitor and the β-glucan synthase inhibitor against this fungus. PMID:24614372

  6. Acute and Chronic Regulation of Aldosterone Production

    PubMed Central

    Hattangady, Namita; Olala, Lawrence; Bollag, Wendy B.; Rainey, William E.

    2011-01-01

    Aldosterone is the major mineralocorticoid synthesized by the adrenal. Secretion of aldosterone is regulated tightly by the adrenocortical glomerulosa cells due to the selective expression of CYP11B2 in the outermost zone, the zona glomerulosa. Aldosterone is largely responsible for regulation of systemic blood pressure through the absorption of electrolytes and water under the regulation of certain specific agonists. Angiotensin II (Ang II), potassium (K+) and adrenocorticotropin (ACTH) are the main physiological agonists which regulate aldosterone secretion. The mechanisms involved in this process may be regulated minutes after a stimulus (acutely) through increased expression and phosphorylation of the steroidogenic acute regulatory (StAR) protein, over hours to days (chronically) by increased expression of the enzymes involved in the synthesis of aldosterone, particularly aldosterone synthase (CYP11B2). Imbalance in any of these processes may lead to several aldosterone excess disorders. In this review we attempt to summarize the key molecular events involved in and specifically attributed to the acute and chronic phases of aldosterone secretion. PMID:21839803

  7. New monomeric and dimeric uridinyl derivatives as inhibitors of chitin synthase.

    PubMed

    Kral, Katarzyna; Bieg, Tadeusz; Nawrot, Urszula; Włodarczyk, Katarzyna; Lalik, Anna; Hahn, Przemysław; Wandzik, Ilona

    2015-08-01

    This study described the synthesis and in vitro evaluation of eight new derivatives of uridine as antifungal agents and inhibitors of chitin synthase. Dimeric uridinyl derivatives synthesized by us did not exhibit significant activity. One of the studied monomeric derivative, 5'-(N-succinyl)-5'-amino-5'-deoxyuridine methyl ester (compound 7) showed activities against several fungal strains (MIC range 0.06-1.00 mg/mL) and inhibited chitin synthase from Saccharomyces cerevisiae (IC50=0.8mM). Moreover compound 7 exhibited synergistic interaction with caspofungin against Candida albicans (FIC index=0.28). PMID:26051755

  8. Fatty Acid Synthase Inhibitor C75 Ameliorates Experimental Colitis

    PubMed Central

    Matsuo, Shingo; Yang, Weng-Lang; Aziz, Monowar; Kameoka, Shingo; Wang, Ping

    2014-01-01

    Abnormalities of lipid metabolism through overexpression of fatty acid synthase (FASN), which catalyzes the formation of long-chain fatty acids, are associated with the development of inflammatory bowel disease (IBD). C75 is a synthetic α-methylene-γ-butyrolactone compound that inhibits FASN activity. We hypothesized that C75 treatment could effectively reduce the severity of experimental colitis. Male C57BL/6 mice were fed 4% dextran sodium sulfate (DSS) for 7 d. C75 (5 mg/kg body weight) or dimethyl sulfoxide (DMSO) (vehicle) was administered intraperitoneally from d 2 to 6. Clinical parameters were monitored daily. Mice were euthanized on d 8 for histological evaluation and measurements of colon length, chemokine, cytokine and inflammatory mediator expression. C75 significantly reduced body weight loss from 23% to 15% on d 8, compared with the vehicle group. The fecal bleeding, diarrhea and colon histological damage scores in the C75-treated group were significantly lower than scores in the vehicle animals. Colon shortening was significantly improved after C75 treatment. C75 protected colon tissues from DSS-induced apoptosis by inhibiting caspase-3 activity. Macrophage inflammatory protein 2, keratinocyte-derived chemokine, myeloperoxidase activity and proinflammatory cytokines (tumor necrosis factor-α, interleukin [IL]-1β and IL-6) in the colon were significantly downregulated in the C75-treated group, compared with the vehicle group. Treatment with C75 in colitis mice inhibited the elevation of FASN, cyclooxygenase-2 and inducible nitric oxide synthase expression as well as IκB degradation in colon tissues. C75 administration alleviates the severity of colon damage and inhibits the activation of inflammatory pathways in DSS-induced colitis. Thus, inhibition of FASN may represent an attractive therapeutic potential for treating IBD. PMID:24306512

  9. Therapeutic perspectives in hypertension: novel means for renin–angiotensin–aldosterone system modulation and emerging device-based approaches

    PubMed Central

    Unger, Thomas; Paulis, Ludovit; Sica, Domenic A.

    2011-01-01

    The conventional antihypertensive therapies including renin–angiotensin–aldosterone system antagonists (converting enzyme inhibitors, receptor blockers, renin inhibitors, and mineralocorticoid receptor blockers), diuretics, β-blockers, and calcium channel blockers are variably successful in achieving the challenging target blood pressure values in hypertensive patients. Difficult to treat hypertension is still a commonly observed problem world-wide. A number of drugs are considered to be used as novel therapies for hypertension. Renalase supplementation, vasopeptidase inhibitors, endothelin antagonists, and especially aldosterone antagonists (aldosterone synthase inhibitors and novel selective mineralocorticoid receptor blockers) are considered an option in resistant hypertension. In addition, the aldosterone antagonists as well as (pro)renin receptor blockers or AT2 receptor agonists might attenuate end-organ damage. This array of medications has now been complemented by a number of new approaches of non-pharmacological strategies including vaccination, genomic interference, controlled breathing, baroreflex activation, and probably most successfully renal denervation techniques. However, the progress on innovative therapies seems to be slow and the problem of resistant hypertension and proper blood pressure control appears to be still persisting. Therefore the regimens of currently available drugs are being fine-tuned, resulting in the establishment of several novel fixed-dose combinations including triple combinations with the aim to facilitate proper blood pressure control. It remains an exciting question which approach will confer the best blood pressure control and risk reduction in this tricky disease. PMID:21951628

  10. Squalene synthase inhibitors: An update on the search for new antihyperlipidemic and antiatherosclerotic agents.

    PubMed

    Kourounakis, A P; Katselou, M G; Matralis, A N; Ladopoulou, E M; Bavavea, E

    2011-01-01

    Atherosclerosis and related heart disease is strongly associated with elevated blood levels of total (and LDL) cholesterol. Due to the widespread incidence as well as severity of this pathological condition, major efforts have been made for the discovery and development of hypocholesteroleamic agents. In the past few decades, HMG-CoA reductase inhibitors (statins) are being extensively used as lipid lowering drugs. These agents act predominantly by inhibiting the enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) that is the rate limiting step of cholesterol biosynthesis. Both the success as well as drawbacks of HMGRIs, have led to the investigation and design of inhibitors of other (downstream) enzymes involved in the multistep cholesterol biosynthetic pathway. One such class of agents consists of the squalene sythase inhibitors which act at the first and solely committed step towards the biosynthesis of the cholesterol nucleus. This target is considered not to interfere with the biosynthesis of other biologically important molecules and thus a better side-effect profile is expected for these inhibitors. Several classes of squalene synthase inhibitors (SQSIs), such as substrate or transition-state analogues, zaragozic acids or 2,8- dioxabicyclo[3.2.1]octane derivatives, dicarboxylic acid and quinuclidine derivatives, 4,1-benzoxazepine as well as substituted morpholine derivatives, have been studied as potent inhibitors of squalene synthase. So far only one benzoxazepine derivative (TAK-475) has been evaluated in advanced clinical trials. In this article we review the up to date research and literature on the therapeutic potential of this relatively new class of compounds, the drug discovery efforts towards the development of active squalene synthase inhibitors, their activity profile and effectiveness, as well as their structure-activity relationships. PMID:21864285

  11. Natural fatty acid synthase inhibitors as potent therapeutic agents for cancers: A review.

    PubMed

    Zhang, Jia-Sui; Lei, Jie-Ping; Wei, Guo-Qing; Chen, Hui; Ma, Chao-Ying; Jiang, He-Zhong

    2016-09-01

    Context Fatty acid synthase (FAS) is the only mammalian enzyme to catalyse the synthesis of fatty acid. The expression level of FAS is related to cancer progression, aggressiveness and metastasis. In recent years, research on natural FAS inhibitors with significant bioactivities and low side effects has increasingly become a new trend. Herein, we present recent research progress on natural fatty acid synthase inhibitors as potent therapeutic agents. Objective This paper is a mini overview of the typical natural FAS inhibitors and their possible mechanism of action in the past 10 years (2004-2014). Method The information was collected and compiled through major databases including Web of Science, PubMed, and CNKI. Results Many natural products induce cancer cells apoptosis by inhibiting FAS expression, with fewer side effects than synthetic inhibitors. Conclusion Natural FAS inhibitors are widely distributed in plants (especially in herbs and foods). Some natural products (mainly phenolics) possessing potent biological activities and stable structures are available as lead compounds to synthesise promising FAS inhibitors. PMID:26864638

  12. Self-consistent synthesis of the squalene synthase inhibitor zaragozic acid C via controlled oligomerization.

    PubMed

    Nicewicz, David A; Satterfield, Andrew D; Schmitt, Daniel C; Johnson, Jeffrey S

    2008-12-24

    Despite the prevalence of repeating subunits in chiral natural products, stereocontrolled oligomerization is a largely unexplored strategy for construction of carbon skeletal frameworks. This report describes the use of silyl glyoxylates as dipolar glycolic acid synthons in a controlled oligomerization reaction for the efficient construction of the squalene synthase inhibitor zaragozic acid C. This new methodology allows rapid, stereocontrolled formation of the carbon skeleton with a desirable protecting group scheme while minimizing functional group repair and oxidation state manipulations. PMID:19053214

  13. Discovery and Characterization of a Class of Pyrazole Inhibitors of Bacterial Undecaprenyl Pyrophosphate Synthase.

    PubMed

    Concha, Nestor; Huang, Jianzhong; Bai, Xiaopeng; Benowitz, Andrew; Brady, Pat; Grady, LaShadric C; Kryn, Luz Helena; Holmes, David; Ingraham, Karen; Jin, Qi; Pothier Kaushansky, Laura; McCloskey, Lynn; Messer, Jeffrey A; O'Keefe, Heather; Patel, Amish; Satz, Alexander L; Sinnamon, Robert H; Schneck, Jessica; Skinner, Steve R; Summerfield, Jennifer; Taylor, Amy; Taylor, J David; Evindar, Ghotas; Stavenger, Robert A

    2016-08-11

    Undecaprenyl pyrophosphate synthase (UppS) is an essential enzyme in bacterial cell wall synthesis. Here we report the discovery of Staphylococcus aureus UppS inhibitors from an Encoded Library Technology screen and demonstrate binding to the hydrophobic substrate site through cocrystallography studies. The use of bacterial strains with regulated uppS expression and inhibitor resistant mutant studies confirmed that the whole cell activity was the result of UppS inhibition, validating UppS as a druggable antibacterial target. PMID:27379833

  14. Discovery, biosynthesis, and mechanism of action of the zaragozic acids: potent inhibitors of squalene synthase.

    PubMed

    Bergstrom, J D; Dufresne, C; Bills, G F; Nallin-Omstead, M; Byrne, K

    1995-01-01

    The zaragozic acids (ZAs), a family of fungal metabolites containing a novel 4,6,7-trihydroxy-2,8-dioxobicyclo[3.2.1]octane-3,4,5-tricarboxylic acid core, were discovered independently by two separate groups screening natural product sources to discover inhibitors of squalene synthase. This family of compounds all contain the same core but differ in their 1-alkyl and their 6-acyl side chains. Production of the ZAs is distributed over an extensive taxonomic range of Ascomycotina or their anamorphic states. The zaragozic acids are very potent inhibitors of squalene synthase that inhibit cholesterol synthesis and lower plasma cholesterol levels in primates. They also inhibit fungal ergosterol synthesis and are potent fungicidal compounds. The biosynthesis of the zaragozic acids appears to proceed through alkyl citrate intermediates and new members of the family have been produced through directed biosynthesis. These potent natural product based inhibitors of squalene synthase have potential to be developed either as cholesterol lowering agents and/or as antifungal agents. PMID:8561474

  15. Zaragozic acids: a family of fungal metabolites that are picomolar competitive inhibitors of squalene synthase.

    PubMed

    Bergstrom, J D; Kurtz, M M; Rew, D J; Amend, A M; Karkas, J D; Bostedor, R G; Bansal, V S; Dufresne, C; VanMiddlesworth, F L; Hensens, O D

    1993-01-01

    Three closely related fungal metabolites, zaragozic acids A, B, and C, that are potent inhibitors of squalene synthase have been isolated and characterized. Zaragozic acids A, B, and C were produced from an unidentified sterile fungal culture, Sporormiella intermedia, and Leptodontium elatius, respectively. The structures of the zaragozic acids and their trimethyl esters were determined by a combination of physical and chemical techniques. The zaragozic acids are characterized by a novel 2,8-dioxobicyclo[3.2.1]octane-4,6,7- trihydroxyl-3,4,5-tricarboxylic acid core and differ from each other in the structures of the 6-acyl and 1-alkyl side chains. They were found to be potent competitive inhibitors of rat liver squalene synthase with apparent Ki values of 78 pM, 29 pM, and 45 pM, respectively. They inhibited cholesterol synthesis in Hep G2 cells, and zaragozic acid A was an inhibitor of acute hepatic cholesterol synthesis in the mouse (50% inhibitory dose of 200 micrograms/kg of body weight). Inhibition of squalene synthase in cells and in vivo was accompanied by an accumulation of label from [3H]mevalonate into farnesyl diphosphate, farnesol, and organic acids. These data indicate that the zaragozic acids are a previously unreported class of therapeutic agents with potential for the treatment of hypercholesterolemia. PMID:8419946

  16. Identification and Evaluation of Novel Acetolactate Synthase Inhibitors as Antifungal Agents

    PubMed Central

    Richie, Daryl L.; Thompson, Katherine V.; Studer, Christian; Prindle, Vivian C.; Aust, Thomas; Riedl, Ralph; Estoppey, David; Tao, Jianshi; Sexton, Jessica A.; Zabawa, Thomas; Drumm, Joseph; Cotesta, Simona; Eichenberger, Jürg; Schuierer, Sven; Hartmann, Nicole; Movva, N. Rao; Tallarico, John A.

    2013-01-01

    High-throughput phenotypic screening against the yeast Saccharomyces cerevisiae revealed a series of triazolopyrimidine-sulfonamide compounds with broad-spectrum antifungal activity, no significant cytotoxicity, and low protein binding. To elucidate the target of this series, we have applied a chemogenomic profiling approach using the S. cerevisiae deletion collection. All compounds of the series yielded highly similar profiles that suggested acetolactate synthase (Ilv2p, which catalyzes the first common step in branched-chain amino acid biosynthesis) as a possible target. The high correlation with profiles of known Ilv2p inhibitors like chlorimuron-ethyl provided further evidence for a similar mechanism of action. Genome-wide mutagenesis in S. cerevisiae identified 13 resistant clones with 3 different mutations in the catalytic subunit of acetolactate synthase that also conferred cross-resistance to established Ilv2p inhibitors. Mapping of the mutations into the published Ilv2p crystal structure outlined the chlorimuron-ethyl binding cavity, and it was possible to dock the triazolopyrimidine-sulfonamide compound into this pocket in silico. However, fungal growth inhibition could be bypassed through supplementation with exogenous branched-chain amino acids or by the addition of serum to the medium in all of the fungal organisms tested except for Aspergillus fumigatus. Thus, these data support the identification of the triazolopyrimidine-sulfonamide compounds as inhibitors of acetolactate synthase but suggest that targeting may be compromised due to the possibility of nutrient bypass in vivo. PMID:23478965

  17. In search of potent and selective inhibitors of neuronal nitric oxide synthase with more simple structures

    PubMed Central

    Jing, Qing; Li, Huiying; Fang, Jianguo; Roman, Linda J.; Martásek, Pavel; Poulos, Thomas L.; Silverman, Richard B.

    2013-01-01

    In certain neurodegenerative diseases damaging levels of nitric oxide (NO) are produced by neuronal nitric oxide synthase (nNOS). It, therefore, is important to develop inhibitors selective for nNOS that do not interfere with other NOS isoforms, especially endothelial NOS (eNOS), which is critical for proper functioning of the cardiovascular system. While we have been successful in developing potent and isoform-selective inhibitors, such as lead compounds 1 and 2, the ease of synthesis and bioavailability have been problematic. Here we describe a new series of compounds including crystal structures of NOS-inhibitor complexes that integrate the advantages of easy synthesis and good biological properties compared to the lead compounds. These results provide the basis for additional structure–activity relationship (SAR) studies to guide further improvement of isozyme selective inhibitors. PMID:23867386

  18. Inhibitors of the sphingomyelin cycle: Sphingomyelin synthases and sphingomyelinases.

    PubMed

    Adada, Mohamad; Luberto, Chiara; Canals, Daniel

    2016-05-01

    Sphingolipids are a class of bioactive lipids, which are key modulators of an increasing number of physiologic and pathophysiologic processes that include cell cycle, apoptosis, angiogenesis, stress and inflammatory responses. Sphingomyelin is an important structural component of biological membranes, and one of the end-points in the synthesis of sphingolipids. Mainly synthetized in the Golgi apparatus, sphingomyelin is transported to all other biological membranes. Upon stimulation, sphingomyelin can be hydrolyzed to ceramide by 5 different sphingomyelinases. The diversity and cellular topology of ceramide allow it to exert multiple biologies. Furthermore, ceramide can be metabolized to many other bioactive sphingolipids. Ceramide, coming from sphingomyelin or other complex sphingolipids, can be hydrolyzed to sphingosine, which can easily change cellular localization. In turn, sphingosine can be recycled to ceramide and to sphingomyelin in the endoplasmic reticulum, completing the sphingomyelin cycle. Our understanding of the roles of various sphingolipids in the regulation of different cellular processes has come from studying the enzymes that regulate these sphingolipids, and their manipulation. The use of pharmacologic inhibitors has been critical for their study, as well as being promising bullets for disease treatment. Some of these diseases involving the sphingomyelin cycle include cancer, inflammation, atherosclerosis, diabetes and some rare diseases such as Niemann-Pick disease. This review will focus on the enzymes involved in the sphingomyelin cycle, their history, and their involvement in pathophysiological processes. Finally, it will describe in details all the small molecules that are being used to inhibit these enzymes and their use in therapeutics. PMID:26200918

  19. Aldosterone response to angiotensin II during hypoxemia

    SciTech Connect

    Colice, G.L.; Ramirez, G.

    1986-07-01

    Exercise stimulates the renin-angiotensin-aldosterone system (RAAS). However, increases in plasma aldosterone concentrations (PAC) are suppressed when exercise is performed at high altitude or under hypoxemic conditions. As the angiotensin-II response to high-altitude exercise is normal, it is speculated that an inhibitor, discharged during hypoxemia, acted to suppress angiotensin-II-mediated aldosterone release. A study was conducted to test this hypothesis, taking into account the measurement of the aldosterone response to exogenous angiotensin II during normoxemia and hypoxemia. It was found that the dose-response curve of PAC to angiotensin II was not significantly inhibited by the considered model of hypoxemia. The hypoxemia-mediated release of an angiotensin II inhibitor does, therefore, not explain the previous observations of PAC suppression during hypoxemic exercise. 28 references.

  20. Effect of a selective thromboxane synthase inhibitor on arterial graft patency and platelet deposition in dogs

    SciTech Connect

    McDaniel, M.D.; Huntsman, W.T.; Miett, T.O.; Cronenwett, J.L.

    1987-08-01

    This study examined the effect of selective thromboxane synthase inhibition and nonselective cyclooxygenase inhibition on vascular graft patency and indium 111-labeled platelet deposition in 35 mongrel dogs undergoing carotid artery replacement with 4 mm X 4 cm polytetrafluoroethylene (PTFE) (one side) and Dacron (opposite side) end-to-end grafts. Aspirin-dipyridamole therapy improved one-week graft patency, from 46% in untreated dogs to 93% in treated dogs. Thromboxane synthase inhibition (U-63557A) improved graft patency in these dogs to 81%. Both drug treatments reduced platelet deposition on Dacron and PTFE grafts by 48% to 68% compared with control dogs. Dacron grafts accumulated significantly more platelets than PTFE grafts but had comparable patency rates. Low-dose aspirin therapy had no significant effect on either graft patency or platelet deposition. All treatment groups showed a 60% to 76% reduction in serum thromboxane B2, but only thromboxane synthase inhibitor treatment increased plasma 6-keto-prostaglandin F1 alpha by 100%. Selective thromboxane synthase inhibition improved small-caliber prosthetic graft patency to the same extent as did conventional cyclooxygenase inhibition in this preliminary study.

  1. Evaluation of Improved Glycogen Synthase Kinase-3α Inhibitors in Models of Acute Myeloid Leukemia

    PubMed Central

    Neumann, Theresa; Benajiba, Lina; Göring, Stefan; Stegmaier, Kimberly; Schmidt, Boris

    2016-01-01

    The challenge for Glycogen Synthase Kinase-3 (GSK-3) inhibitor design lies in achieving high selectivity for one isoform over the other. The therapy of certain diseases, such as acute myeloid leukemia (AML) may require α-isoform specific targeting. The scorpion shaped GSK-3 inhibitors developed by our group achieved the highest GSK-3α selectivity reported so far, but suffered from insufficient aqueous solubility. This work presents the solubility-driven optimization of our isoform-selective inhibitors using a scorpion shaped lead. Among 15 novel compounds, compound 27 showed high activity against GSK-3α/β with the highest GSK-3α selectivity reported to date. Compound 27 was profiled for bioavailability and toxicity in a zebrafish embryo phenotype assay. Selective GSK-3α targeting in AML cell lines was achieved with compound 27, resulting in a strong differentiation phenotype and colony formation impairment, confirming the potential of GSK-3α inhibition in AML therapy. PMID:26496242

  2. Aldosterone and Renin Test

    MedlinePlus

    ... renin tests are used to evaluate whether the adrenal glands are producing appropriate amounts of aldosterone and to ... caused by the overproduction of aldosterone by the adrenal glands , usually by a benign tumor of one of ...

  3. Aldosterone sensitizes connecting tubule glomerular feedback via the aldosterone receptor GPR30

    PubMed Central

    Ren, YiLin; D'Ambrosio, Martin A.; Garvin, Jeffrey L.; Leung, Pablo; Kutskill, Kristopher; Wang, Hong; Peterson, Edward L.

    2014-01-01

    Increasing Na delivery to epithelial Na channels (ENaC) in the connecting tubule (CNT) dilates the afferent arteriole (Af-Art), a process we call connecting tubule glomerular feedback (CTGF). We hypothesize that aldosterone sensitizes CTGF via a nongenomic mechanism that stimulates CNT ENaC via the aldosterone receptor GPR30. Rabbit Af-Arts and their adherent CNTs were microdissected and simultaneously perfused. Two consecutive CTGF curves were elicited by increasing luminal NaCl in the CNT. During the control period, the concentration of NaCl that elicited a half-maximal response (EC50) was 37.0 ± 2.0 mmol/l; addition of aldosterone 10−8 mol/l to the CNT lumen caused a left-shift (decrease) in EC50 to 19.3 ± 1.3 mmol/l (P = 0.001 vs. control; n = 6). Neither the transcription inhibitor actinomycin D nor the translation inhibitor cycloheximide prevented the effect of aldosterone (control EC50 = 34.7 ± 1.9 mmol/l; aldosterone+actinomycin D EC50 = 22.6 ± 1.6 mmol/l; P < 0.001 and control EC50 = 32.4 ± 4.3 mmol/l; aldosterone+cycloheximide EC50 = 17.4 ± 3.3 mmol/l; P < 0.001). The aldosterone antagonist eplerenone prevented the sensitization of CTGF by aldosterone (control EC50 = 33.2 ± 1.7 mmol/l; aldosterone+eplerenone EC50 = 33.5 ± 1.3 mmol/l; n = 7). The GPR30 receptor blocker G-36 blocked the sensitization of CTGF by aldosterone (aldosterone EC50 = 16.5 ± 1.9 mmol/l; aldosterone+G-36 EC50 = 29.0 ± 2.1 mmol/l; n = 7; P < 0.001). Finally, we found that the sensitization of CTGF by aldosterone was mediated, at least in part, by the sodium/hydrogen exchanger (NHE). We conclude that aldosterone in the CNT lumen sensitizes CTGF via a nongenomic effect involving GPR30 receptors and NHE. Sensitized CTGF induced by aldosterone may contribute to renal damage by increasing Af-Art dilation and glomerular capillary pressure (glomerular barotrauma). PMID:24966088

  4. ATP Synthase and the Actions of Inhibitors Utilized To Study Its Roles in Human Health, Disease, and Other Scientific Areas

    PubMed Central

    Hong, Sangjin; Pedersen, Peter L.

    2008-01-01

    Summary: ATP synthase, a double-motor enzyme, plays various roles in the cell, participating not only in ATP synthesis but in ATP hydrolysis-dependent processes and in the regulation of a proton gradient across some membrane-dependent systems. Recent studies of ATP synthase as a potential molecular target for the treatment of some human diseases have displayed promising results, and this enzyme is now emerging as an attractive molecular target for the development of new therapies for a variety of diseases. Significantly, ATP synthase, because of its complex structure, is inhibited by a number of different inhibitors and provides diverse possibilities in the development of new ATP synthase-directed agents. In this review, we classify over 250 natural and synthetic inhibitors of ATP synthase reported to date and present their inhibitory sites and their known or proposed modes of action. The rich source of ATP synthase inhibitors and their known or purported sites of action presented in this review should provide valuable insights into their applications as potential scaffolds for new therapeutics for human and animal diseases as well as for the discovery of new pesticides and herbicides to help protect the world's food supply. Finally, as ATP synthase is now known to consist of two unique nanomotors involved in making ATP from ADP and Pi, the information provided in this review may greatly assist those investigators entering the emerging field of nanotechnology. PMID:19052322

  5. Biomimetic Design Results in a Potent Allosteric Inhibitor of Dihydrodipicolinate Synthase from Campylobacter jejuni.

    PubMed

    Skovpen, Yulia V; Conly, Cuylar J T; Sanders, David A R; Palmer, David R J

    2016-02-17

    Dihydrodipicolinate synthase (DHDPS), an enzyme required for bacterial peptidoglycan biosynthesis, catalyzes the condensation of pyruvate and β-aspartate semialdehyde (ASA) to form a cyclic product which dehydrates to form dihydrodipicolinate. DHDPS has, for several years, been considered a putative target for novel antibiotics. We have designed the first potent inhibitor of this enzyme by mimicking its natural allosteric regulation by lysine, and obtained a crystal structure of the protein-inhibitor complex at 2.2 Å resolution. This novel inhibitor, which we named "bislysine", resembles two lysine molecules linked by an ethylene bridge between the α-carbon atoms. Bislysine is a mixed partial inhibitor with respect to the first substrate, pyruvate, and a noncompetitive partial inhibitor with respect to ASA, and binds to all forms of the enzyme with a Ki near 200 nM, more than 300 times more tightly than lysine. Hill plots show that the inhibition is cooperative, indicating that the allosteric sites are not independent despite being located on opposite sides of the protein tetramer, separated by approximately 50 Å. A mutant enzyme resistant to lysine inhibition, Y110F, is strongly inhibited by this novel inhibitor, suggesting this may be a promising strategy for antibiotic development. PMID:26836694

  6. Crystal Structures of Constitutive Nitric Oxide Synthases in Complex with De Novo Designed Inhibitors

    PubMed Central

    Igarashi, Jotaro; Li, Huiying; Jamal, Joumana; Ji, Haitao; Fang, Jianguo; Lawton, Graham R.; Silverman, Richard B.; Poulos, Thomas L.

    2011-01-01

    New nitric oxide synthase (NOS) inhibitors were designed de novo with knowledge gathered from the studies on the nNOS-selective dipeptide inhibitors. Each of the new inhibitors consists of three fragments: an aminopyridine ring, a pyrrolidine, and a tail of various length and polarity. The in vitro inhibitory assays indicate good potency and isoform selectivity for some of the compounds. Crystal structures of these inhibitors bound to either wild type or mutant nNOS and eNOS have confirmed design expectations. The aminopyridine ring mimics the guanidinium group of L-arginine and functions as an anchor to place the compound in the NOS active site where it hydrogen bonds to a conserved Glu. The rigidity of the pyrrolidine ring places the pyrrolidine ring nitrogen between the same conserved Glu and the selective residue nNOS Asp597/eNOS Asn368 which results in similar interactions observed with the α-amino group of dipeptide inhibitors bound to nNOS. These structures provide additional information to help in the design of inhibitors with greater potency, physico-chemical properties, and isoform selectivity. PMID:19296678

  7. Exploring the binding conformations of bulkier dipeptide amide inhibitors in constitutive nitric oxide synthases.

    PubMed

    Li, Huiying; Flinspach, Mack L; Igarashi, Jotaro; Jamal, Joumana; Yang, Weiping; Gómez-Vidal, José Antonio; Litzinger, Elizabeth A; Huang, Hui; Erdal, Erik P; Silverman, Richard B; Poulos, Thomas L

    2005-11-22

    A series of L-nitroarginine-based dipeptide inhibitors are highly selective for neuronal nitric oxide synthase (nNOS) over the endothelial isoform (eNOS). Crystal structures of these dipeptides bound to both isoforms revealed two different conformations, curled in nNOS and extended in eNOS, corresponding to higher and lower binding affinity to the two isoforms, respectively. In previous studies we found that the primary reason for selectivity is that Asp597 in nNOS, which is Asn368 in eNOS, provides greater electrostatic stabilization in the inhibitor complex. While this is the case for smaller dipeptide inhibitors, electrostatic stabilization may no longer be the sole determinant for isoform selectivity with bulkier dipeptide inhibitors. Another residue farther away from the active site, Met336 in nNOS (Val106 in eNOS), is in contact with bulkier dipeptide inhibitors. Double mutants were made to exchange the D597/M336 pair in nNOS with N368/V106 in eNOS. Here we report crystal structures and inhibition constants for bulkier dipeptide inhibitors bound to nNOS and eNOS that illustrate the important role played by residues near the entry to the active site in isoform selective inhibition. PMID:16285725

  8. Substituted Pyrrolo[2,3-d]pyrimidines as Cryptosporidium hominis Thymidylate Synthase Inhibitors

    PubMed Central

    Kumar, Vidya P.; Frey, Kathleen M.; Wang, Yiqiang; Jain, Hitesh K.; Gangjee, Aleem; Anderson, Karen S.

    2013-01-01

    Cryptosporidiosis, a gastrointestinal disease caused by a protozoan Cryptosporidium hominis is often fatal in immunocompromised individuals. There is little clinical data to show that the existing treatment by nitazoxanide and paromomycin is effective in immunocompromised individuals1, 2. Thymidylate synthase (TS) and dihydrofolate reductase (DHFR) are essential enzymes in the folate biosynthesis pathway and are well established as drug targets in cancer and malaria. A novel series of classical antifolates, 2-amino-4-oxo-5-substituted pyrrolo[2,3-d]pyrimidines have been evaluated as Cryptosporidium hominis thymidylate synthase (ChTS) inhibitors. Crystal structure in complex with the most potent compound, a 2’-chlorophenyl with a sulfur bridge with a Ki of 8.83 ± 0.67 nM is discussed in terms of several Van de Waals, hydrophobic and hydrogen bond interactions with the protein residues and the substrate analog 5-fluorodeoxyuridine monophosphate. Of these interactions, two interactions with the non-conserved residues (A287 and S290) offer an opportunity to develop ChTS specific inhibitors. Compound 6 serves as a lead compound for analog design and its crystal structure provides clues for the design of ChTS specific inhibitors. PMID:23927969

  9. Thiolactomycin-Based Inhibitors of Bacterial β-Ketoacyl-ACP Synthases with in Vivo Activity.

    PubMed

    Bommineni, Gopal R; Kapilashrami, Kanishk; Cummings, Jason E; Lu, Yang; Knudson, Susan E; Gu, Chendi; Walker, Stephen G; Slayden, Richard A; Tonge, Peter J

    2016-06-01

    β-Ketoacyl-ACP synthases (KAS) are key enzymes involved in the type II bacterial fatty acid biosynthesis (FASII) pathway and are putative targets for antibacterial discovery. Several natural product KAS inhibitors have previously been reported, including thiolactomycin (TLM), which is produced by Nocardia spp. Here we describe the synthesis and characterization of optically pure 5R-thiolactomycin (TLM) analogues that show improved whole cell activity against bacterial strains including methicillin-resistant Staphylococcus aureus (MRSA) and priority pathogens such as Francisella tularensis and Burkholderia pseudomallei. In addition, we identify TLM analogues with in vivo efficacy against MRSA and Klebsiella pneumoniae in animal models of infection. PMID:27187871

  10. Reduced food intake and body weight in mice treated with fatty acid synthase inhibitors.

    PubMed

    Loftus, T M; Jaworsky, D E; Frehywot, G L; Townsend, C A; Ronnett, G V; Lane, M D; Kuhajda, F P

    2000-06-30

    With the escalation of obesity-related disease, there is great interest in defining the mechanisms that control appetite and body weight. We have identified a link between anabolic energy metabolism and appetite control. Both systemic and intracerebroventricular treatment of mice with fatty acid synthase (FAS) inhibitors (cerulenin and a synthetic compound C75) led to inhibition of feeding and dramatic weight loss. C75 inhibited expression of the prophagic signal neuropeptide Y in the hypothalamus and acted in a leptin-independent manner that appears to be mediated by malonyl-coenzyme A. Thus, FAS may represent an important link in feeding regulation and may be a potential therapeutic target. PMID:10875926

  11. First small molecular inhibitors of T. brucei dolicholphosphate mannose synthase (DPMS), a validated drug target in African sleeping sickness

    PubMed Central

    Smith, Terry K.; Young, Benjamin L.; Denton, Helen; Hughes, David L.; Wagner, Gerd K.

    2013-01-01

    Drug-like molecules with activity against Trypanosoma brucei are urgently required as potential therapeutics for the treatment of African sleeping sickness. Starting from known inhibitors of other glycosyltransferases, we have developed the first small molecular inhibitors of dolicholphosphate mannose synthase (DPMS), a mannosyltransferase critically involved in glycoconjugate biosynthesis in T. brucei. We show that these DPMS inhibitors prevent the biosynthesis of glycosylphosphatidylinositol (GPI) anchors, and possess trypanocidal activity against live trypanosomes. PMID:19217283

  12. In vivo pharmacological evaluation of two novel type II (inducible) nitric oxide synthase inhibitors.

    PubMed

    Tracey, W R; Nakane, M; Basha, F; Carter, G

    1995-05-01

    Selective type II (inducible) nitric oxide synthase (NOS) inhibitors have several potential therapeutic applications, including treatment of sepsis, diabetes, and autoimmune diseases. The ability of two novel, selective inhibitors of type II NOS, S-ethylisothiourea (EIT) and 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), to inhibit type II NOS function in vivo was studied in lipopolysaccharide (LPS) treated rats. Type II NOS activity was assessed by measuring changes in plasma nitrite and nitrate concentrations ([NOx]). Both EIT and AMT elicited a dose-dependent and > 95% inhibition of the LPS-induced increase in plasma [NOx]. The ED50 values for EIT and AMT were 0.4 and 0.2 mg/kg, respectively. In addition, the administration of LPS and either NOS inhibitor resulted in a dose-dependent increase in animal mortality; neither compound was lethal when administered alone. Pretreatment with L-arginine (but not D-arginine) prevented the mortality, while not affecting the type II NOS-dependent NO production, suggesting the toxicity may be due to inhibition of one of the other NOS isoforms (endothelial or neuronal). Thus, although EIT and AMT are potent inhibitors of type II NOS function in vivo, type II NOS inhibitors of even greater selectivity may need to be developed for therapeutic applications. PMID:7585335

  13. Potent, Highly Selective, and Orally Bioavailable Gem-Difluorinated Monocationic Inhibitors of Neuronal Nitric Oxide Synthase

    PubMed Central

    Xue, Fengtian; Li, Huiying; Delker, Silvia L.; Fang, Jianguo; Martásek, Pavel; Roman, Linda J.; Poulos, Thomas L.; Silverman, Richard B.

    2010-01-01

    In our efforts to discover neuronal isoform selective nitric oxide synthase (NOS) inhibitors we have developed a series of compounds containing a pyrrolidine ring with two stereogenic centers. The enantiomerically pure compounds, (S,S) vs. (R,R), exhibited two different binding orientations, with (R,R) inhibitors showing much better potency and selectivity. To improve the bioavailability of these inhibitors we have introduced a CF2 moiety geminal to an amino group in the long tail of one of these inhibitors, which reduced its basicity, resulting in compounds with monocationic character under physiological pH conditions. Biological evaluations have led to a nNOS inhibitor with a Ki of 36 nM and high selectivity for nNOS over eNOS (3800-fold) and iNOS (1400-fold). MM-PBSA calculations indicated that the low pKa NH is, at least, partially protonated when bound to the active site. A comparison of rat oral bioavailability of the difluorinated compound to the parent molecule shows 22% for the difluorinated compound versus essentially no oral bioavailability for the parent compound. This indicates that the goal of this research to make compounds with only one protonated nitrogen atom at physiological pH to allow for membrane permeability, but which can become protonated when bound to NOS, has been accomplished. PMID:20843082

  14. Inhibitor-bound complexes of dihydrofolate reductase-thymidylate synthase from Babesia bovis

    PubMed Central

    Begley, Darren W.; Edwards, Thomas E.; Raymond, Amy C.; Smith, Eric R.; Hartley, Robert C.; Abendroth, Jan; Sankaran, Banumathi; Lorimer, Donald D.; Myler, Peter J.; Staker, Bart L.; Stewart, Lance J.

    2011-01-01

    Babesiosis is a tick-borne disease caused by eukaryotic Babesia parasites which are morphologically similar to Plasmodium falciparum, the causative agent of malaria in humans. Like Plasmodium, different species of Babesia are tuned to infect different mammalian hosts, including rats, dogs, horses and cattle. Most species of Plasmodium and Babesia possess an essential bifunctional enzyme for nucleotide synthesis and folate metabolism: dihydrofolate reductase-thymidylate synthase. Although thymidylate synthase is highly conserved across organisms, the bifunctional form of this enzyme is relatively uncommon in nature. The structural characterization of dihydrofolate reductase-thymidylate synthase in Babesia bovis, the causative agent of babesiosis in livestock cattle, is reported here. The apo state is compared with structures that contain dUMP, NADP and two different antifolate inhibitors: pemetrexed and raltitrexed. The complexes reveal modes of binding similar to that seen in drug-resistant malaria strains and point to the utility of applying structural studies with proven cancer chemotherapies towards infectious disease research. PMID:21904052

  15. Quantitative Proteomic Analysis of Human Lung Tumor Xenografts Treated with the Ectopic ATP Synthase Inhibitor Citreoviridin

    PubMed Central

    Wu, Yi-Hsuan; Hu, Chia-Wei; Chien, Chih-Wei; Chen, Yu-Ju; Huang, Hsuan-Cheng; Juan, Hsueh-Fen

    2013-01-01

    ATP synthase is present on the plasma membrane of several types of cancer cells. Citreoviridin, an ATP synthase inhibitor, selectively suppresses the proliferation and growth of lung cancer without affecting normal cells. However, the global effects of targeting ectopic ATP synthase in vivo have not been well defined. In this study, we performed quantitative proteomic analysis using isobaric tags for relative and absolute quantitation (iTRAQ) and provided a comprehensive insight into the complicated regulation by citreoviridin in a lung cancer xenograft model. With high reproducibility of the quantitation, we obtained quantitative proteomic profiling with 2,659 proteins identified. Bioinformatics analysis of the 141 differentially expressed proteins selected by their relative abundance revealed that citreoviridin induces alterations in the expression of glucose metabolism-related enzymes in lung cancer. The up-regulation of enzymes involved in gluconeogenesis and storage of glucose indicated that citreoviridin may reduce the glycolytic intermediates for macromolecule synthesis and inhibit cell proliferation. Using comprehensive proteomics, the results identify metabolic aspects that help explain the antitumorigenic effect of citreoviridin in lung cancer, which may lead to a better understanding of the links between metabolism and tumorigenesis in cancer therapy. PMID:23990911

  16. CETSA screening identifies known and novel thymidylate synthase inhibitors and slow intracellular activation of 5-fluorouracil.

    PubMed

    Almqvist, Helena; Axelsson, Hanna; Jafari, Rozbeh; Dan, Chen; Mateus, André; Haraldsson, Martin; Larsson, Andreas; Martinez Molina, Daniel; Artursson, Per; Lundbäck, Thomas; Nordlund, Pär

    2016-01-01

    Target engagement is a critical factor for therapeutic efficacy. Assessment of compound binding to native target proteins in live cells is therefore highly desirable in all stages of drug discovery. We report here the first compound library screen based on biophysical measurements of intracellular target binding, exemplified by human thymidylate synthase (TS). The screen selected accurately for all the tested known drugs acting on TS. We also identified TS inhibitors with novel chemistry and marketed drugs that were not previously known to target TS, including the DNA methyltransferase inhibitor decitabine. By following the cellular uptake and enzymatic conversion of known drugs we correlated the appearance of active metabolites over time with intracellular target engagement. These data distinguished a much slower activation of 5-fluorouracil when compared with nucleoside-based drugs. The approach establishes efficient means to associate drug uptake and activation with target binding during drug discovery. PMID:27010513

  17. CETSA screening identifies known and novel thymidylate synthase inhibitors and slow intracellular activation of 5-fluorouracil

    NASA Astrophysics Data System (ADS)

    Almqvist, Helena; Axelsson, Hanna; Jafari, Rozbeh; Dan, Chen; Mateus, André; Haraldsson, Martin; Larsson, Andreas; Molina, Daniel Martinez; Artursson, Per; Lundbäck, Thomas; Nordlund, Pär

    2016-03-01

    Target engagement is a critical factor for therapeutic efficacy. Assessment of compound binding to native target proteins in live cells is therefore highly desirable in all stages of drug discovery. We report here the first compound library screen based on biophysical measurements of intracellular target binding, exemplified by human thymidylate synthase (TS). The screen selected accurately for all the tested known drugs acting on TS. We also identified TS inhibitors with novel chemistry and marketed drugs that were not previously known to target TS, including the DNA methyltransferase inhibitor decitabine. By following the cellular uptake and enzymatic conversion of known drugs we correlated the appearance of active metabolites over time with intracellular target engagement. These data distinguished a much slower activation of 5-fluorouracil when compared with nucleoside-based drugs. The approach establishes efficient means to associate drug uptake and activation with target binding during drug discovery.

  18. N-Substituted acetamidines and 2-methylimidazole derivatives as selective inhibitors of neuronal nitric oxide synthase.

    PubMed

    Maccallini, Cristina; Patruno, Antonia; Lannutti, Fabio; Ammazzalorso, Alessandra; De Filippis, Barbara; Fantacuzzi, Marialuigia; Franceschelli, Sara; Giampietro, Letizia; Masella, Simona; Felaco, Mario; Re, Nazzareno; Amoroso, Rosa

    2010-11-15

    A series of N-substituted acetamidines and 2-methylimidazole derivatives structurally related to W1400 were synthesized and evaluated as Nitric Oxide Synthase (NOS) inhibitors. Analogs with sterically hindering isopropyl and phenyl substituents on the benzylic carbon connecting the aromatic core of W1400 to the acetamidine nitrogen, showed good inhibitory potency for nNOS (IC(50)=0.2 and 0.3 μM) and selectivity over eNOS (500 and 1166) and to a lesser extent over iNOS (50 and 100). A molecular modeling study allowed to shed light on the effects of the structural modifications on the selectivity of the designed inhibitors toward the different NOS isoforms. PMID:20933416

  19. CETSA screening identifies known and novel thymidylate synthase inhibitors and slow intracellular activation of 5-fluorouracil

    PubMed Central

    Almqvist, Helena; Axelsson, Hanna; Jafari, Rozbeh; Dan, Chen; Mateus, André; Haraldsson, Martin; Larsson, Andreas; Molina, Daniel Martinez; Artursson, Per; Lundbäck, Thomas; Nordlund, Pär

    2016-01-01

    Target engagement is a critical factor for therapeutic efficacy. Assessment of compound binding to native target proteins in live cells is therefore highly desirable in all stages of drug discovery. We report here the first compound library screen based on biophysical measurements of intracellular target binding, exemplified by human thymidylate synthase (TS). The screen selected accurately for all the tested known drugs acting on TS. We also identified TS inhibitors with novel chemistry and marketed drugs that were not previously known to target TS, including the DNA methyltransferase inhibitor decitabine. By following the cellular uptake and enzymatic conversion of known drugs we correlated the appearance of active metabolites over time with intracellular target engagement. These data distinguished a much slower activation of 5-fluorouracil when compared with nucleoside-based drugs. The approach establishes efficient means to associate drug uptake and activation with target binding during drug discovery. PMID:27010513

  20. Role of ACTH and Other Hormones in the Regulation of Aldosterone Production in Primary Aldosteronism

    PubMed Central

    El Ghorayeb, Nada; Bourdeau, Isabelle; Lacroix, André

    2016-01-01

    aldosteronism, a chimeric CYP11B2 becomes regulated by ACTH activating its chimeric CYP11B1 promoter of aldosterone synthase in bilateral adrenal fasciculate-like hyperplasia. This review will focus on the role of ACTH on excess aldosterone secretion in PA with particular focus on the aberrant expression of MC2R in comparison with other aberrant ligands and their GPCRs in this frequent pathology. PMID:27445975

  1. [Hematopoietic prostaglandin D synthase inhibitors for the treatment of duchenne muscular dystrophy].

    PubMed

    Kamauchi, Shinya; Urade, Yoshihiro

    2011-11-01

    Duchenne muscular dystrophy (DMD) is a severe X-linked muscle disease, characterized by progressive skeletal muscle atrophy and weakness. DMD is caused by mutations in the dystrophin gene, which encodes for the cytoskeletal protein dystrophin. DMD is one of the most common types of muscular dystrophies, affecting approximately 1 in 3,500 boys. There is no complete cure for this disease. Clinical trials for gene transfer therapy as a treatment for DMD have been performed but mainly in animal models. Hematopoietic prostaglandin (PG) D synthase (H-PGDS) was found to be induced in grouped necrotic muscle fibers of DMD patients and animal models, mdx mice, and DMD dogs. We found an orally active H-PGDS inhibitor (HQL-79) and determined the 3D structure of the inhibitor-human H-PGDS complex by X-ray crystallography. Oral administration of HQL-79 markedly suppressed prostaglandin D2 (PGD2) production, reduced necrotic muscle volume, and improved muscle strength in mdx dystrophic mice. Based on the high-resolution 3D structures of the inhibitor-H-PGDS complex, we designed alternative H-PGDS inhibitors, which were 100- to 3000-times more potent than HQL-79, as assessed by in vitro and in vivo analyses. We used these novel inhibitors for the treatment of DMD dogs and confirmed that oral administration of these inhibitors prevented skeletal muscle atrophy and weakness by decreasing PGD2 production. These results indicate that PGD2, synthesized by H-PGDS, is involved in the expansion of muscle necrosis in DMD. Thus, inhibition of H-PGDS by using inhibitors is a novel therapy for DMD. PMID:22068479

  2. Identification and Characterization of Novel Microsomal Prostaglandin E Synthase-1 Inhibitors for Analgesia.

    PubMed

    Chandrasekhar, Srinivasan; Harvey, Anita K; Yu, Xiao-Peng; Chambers, Mark G; Oskins, Jennifer L; Lin, Chaohua; Seng, Thomas W; Thibodeaux, Stefan J; Norman, Bryan H; Hughes, Norman E; Schiffler, Matthew A; Fisher, Matthew J

    2016-03-01

    Prostaglandin (PG) E2 plays a critical role in eliciting inflammation. Nonsteroidal anti-inflammatory drugs and selective inhibitors of cyclooxygenase, which block PGE2 production, have been used as key agents in treating inflammation and pain associated with arthritis and other conditions. However, these agents have significant side effects such as gastrointestinal bleeding and myocardial infarction, since they also block the production of prostanoids that are critical for other normal physiologic functions. Microsomal prostaglandin E2 synthase-1 is a membrane-bound terminal enzyme in the prostanoid pathway, which acts downstream of cyclooxygenase 2 and is responsible for PGE2 production during inflammation. Thus, inhibition of this enzyme would be expected to block PGE2 production without inhibiting other prostanoids and would provide analgesic efficacy without the side effects. In this report, we describe novel microsomal prostaglandin E2 synthase-1 inhibitors that are potent in blocking PGE2 production and are efficacious in a guinea pig monoiodoacetate model of arthralgia. These molecules may be useful in treating the signs and symptoms associated with arthritis. PMID:26740668

  3. Increase of 20-HETE synthase after brain ischemia in rats revealed by PET study with 11C-labeled 20-HETE synthase-specific inhibitor

    PubMed Central

    Kawasaki, Toshiyuki; Marumo, Toshiyuki; Shirakami, Keiko; Mori, Tomoko; Doi, Hisashi; Suzuki, Masaaki; Watanabe, Yasuyoshi; Chaki, Shigeyuki; Nakazato, Atsuro; Ago, Yukio; Hashimoto, Hitoshi; Matsuda, Toshio; Baba, Akemichi; Onoe, Hirotaka

    2012-01-01

    20-Hydroxyeicosatetraenoic acid (20-HETE), an arachidonic acid metabolite known to be produced after cerebral ischemia, has been implicated in ischemic and reperfusion injury by mediating vasoconstriction. To develop a positron emission tomography (PET) probe for 20-HETE synthase imaging, which might be useful for monitoring vasoconstrictive processes in patients with brain ischemia, we synthesized a 11C-labeled specific 20-HETE synthase inhibitor, N′(4-dimethylaminohexyloxy)phenyl imidazole ([11C]TROA). Autoradiographic study showed that [11C]TROA has high-specific binding in the kidney and liver consistent with the previously reported distribution of 20-HETE synthase. Using transient middle cerebral artery occlusion in rats, PET study showed significant increases in the binding of [11C]TROA in the ipsilateral hemisphere of rat brains after 7 and 10 days, which was blocked by co-injection of excess amounts of TROA (10 mg/kg). The increased [11C]TROA binding on the ipsilateral side returned to basal levels within 14 days. In addition, quantitative real-time PCR revealed that increased expression of 20-HETE synthase was only shown on the ipsilateral side on day 7. These results indicate that [11C]TROA might be a useful PET probe for imaging of 20-HETE synthase in patients with cerebral ischemia. PMID:22669478

  4. Accessible Chiral Linker to Enhance Potency and Selectivity of Neuronal Nitric Oxide Synthase Inhibitors

    PubMed Central

    2013-01-01

    The three important mammalian isozymes of nitric oxide synthase (NOS) are neuronal NOS (nNOS), endothelial NOS (eNOS), and inducible NOS (iNOS). Inhibitors of nNOS show promise as treatments for neurodegenerative diseases. Eight easily synthesized compounds containing either one (20a,b) or two (9a–d; 15a,b) 2-amino-4-methylpyridine groups with a chiral pyrrolidine linker were designed as selective nNOS inhibitors. Inhibitor 9c is the best of these compounds, having a potency of 9.7 nM and dual selectivity of 693 and 295 against eNOS and iNOS, respectively. Crystal structures of nNOS complexed with either 9a or 9c show a double-headed binding mode, where each 2-aminopyridine headgroup interacts with either a nNOS active site Glu residue or a heme propionate. In addition, the pyrrolidine nitrogen of 9c contributes additional hydrogen bonds to the heme propionate, resulting in a unique binding orientation. In contrast, the lack of hydrogen bonds from the pyrrolidine of 9a to the heme propionate allows the inhibitor to adopt two different binding orientations. Both 9a and 9c bind to eNOS in a single-headed mode, which is the structural basis for the isozyme selectivity. PMID:24660051

  5. Inhibitors of Glycogen Synthase Kinase 3 with Exquisite Kinome-Wide Selectivity and Their Functional Effects.

    PubMed

    Wagner, Florence F; Bishop, Joshua A; Gale, Jennifer P; Shi, Xi; Walk, Michelle; Ketterman, Joshua; Patnaik, Debasis; Barker, Doug; Walpita, Deepika; Campbell, Arthur J; Nguyen, Shannon; Lewis, Michael; Ross, Linda; Weïwer, Michel; An, W Frank; Germain, Andrew R; Nag, Partha P; Metkar, Shailesh; Kaya, Taner; Dandapani, Sivaraman; Olson, David E; Barbe, Anne-Laure; Lazzaro, Fanny; Sacher, Joshua R; Cheah, Jaime H; Fei, David; Perez, Jose; Munoz, Benito; Palmer, Michelle; Stegmaier, Kimberly; Schreiber, Stuart L; Scolnick, Edward; Zhang, Yan-Ling; Haggarty, Stephen J; Holson, Edward B; Pan, Jen Q

    2016-07-15

    The mood stabilizer lithium, the first-line treatment for bipolar disorder, is hypothesized to exert its effects through direct inhibition of glycogen synthase kinase 3 (GSK3) and indirectly by increasing GSK3's inhibitory serine phosphorylation. GSK3 comprises two highly similar paralogs, GSK3α and GSK3β, which are key regulatory kinases in the canonical Wnt pathway. GSK3 stands as a nodal target within this pathway and is an attractive therapeutic target for multiple indications. Despite being an active field of research for the past 20 years, many GSK3 inhibitors demonstrate either poor to moderate selectivity versus the broader human kinome or physicochemical properties unsuitable for use in in vitro systems or in vivo models. A nonconventional analysis of data from a GSK3β inhibitor high-throughput screening campaign, which excluded known GSK3 inhibitor chemotypes, led to the discovery of a novel pyrazolo-tetrahydroquinolinone scaffold with unparalleled kinome-wide selectivity for the GSK3 kinases. Taking advantage of an uncommon tridentate interaction with the hinge region of GSK3, we developed highly selective and potent GSK3 inhibitors, BRD1652 and BRD0209, which demonstrated in vivo efficacy in a dopaminergic signaling paradigm modeling mood-related disorders. These new chemical probes open the way for exclusive analyses of the function of GSK3 kinases in multiple signaling pathways involved in many prevalent disorders. PMID:27128528

  6. Selective Monocationic Inhibitors of Neuronal Nitric Oxide Synthase. Binding Mode Insights from Molecular Dynamics Simulations

    PubMed Central

    Huang, He; Ji, Haitao; Li, Huiying; Jing, Qing; Labby, Kristin Jansen; Martásek, Pavel; Roman, Linda J.; Poulos, Thomas L.; Silverman, Richard B.

    2012-01-01

    The reduction of pathophysiologic levels of nitric oxide through inhibition of neuronal nitric oxide synthase (nNOS) has the potential to be therapeutically beneficial in various neurodegenerative diseases. We have developed a series of pyrrolidine-based nNOS inhibitors that exhibit excellent potencies and isoform selectivities (J. Am. Chem. Soc. 2010, 132, 5437). However, there are still important challenges, such as how to decrease the multiple positive charges derived from basic amino groups, which contribute to poor bioavailability, without losing potency and/or selectivity. Here we present an interdisciplinary study combining molecular docking, crystallography, molecular dynamics simulations, synthesis, and enzymology to explore potential pharmacophoric features of nNOS inhibitors and to design potent and selective monocationic nNOS inhibitors. The simulation results indicate that different hydrogen bond patterns, electrostatic interactions, hydrophobic interactions, and a water molecule bridge are key factors for stabilizing ligands and controlling ligand orientation. We find that a heteroatom in the aromatic head or linker chain of the ligand provides additional stability and blocks the substrate binding pocket. Finally, the computational insights are experimentally validated with double-headed pyridine analogs. The compounds reported here are among the most potent and selective monocationic pyrrolidine-based nNOS inhibitors reported to date, and 10 shows improved membrane permeability. PMID:22731813

  7. Aldosterone and aldosterone receptor antagonists in patients with chronic heart failure

    PubMed Central

    Nappi, Jean M; Sieg, Adam

    2011-01-01

    Aldosterone is a mineralocorticoid hormone synthesized by the adrenal glands that has several regulatory functions to help the body maintain normal volume status and electrolyte balance. Studies have shown significantly higher levels of aldosterone secretion in patients with congestive heart failure compared with normal patients. Elevated levels of aldosterone have been shown to elevate blood pressure, cause left ventricular hypertrophy, and promote cardiac fibrosis. An appreciation of the true role of aldosterone in patients with chronic heart failure did not become apparent until the publication of the Randomized Aldactone Evaluation Study. Until recently, the use of aldosterone receptor antagonists has been limited to patients with severe heart failure and patients with heart failure following myocardial infarction. The Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure (EMPHASIS-HF) study added additional evidence to support the expanded use of aldosterone receptor antagonists in heart failure patients. The results of the EMPHASIS-HF trial showed that patients with mild-to-moderate (New York Heart Association Class II) heart failure had reductions in mortality and hospitalizations from the addition of eplerenone to optimal medical therapy. Evidence remains elusive about the exact mechanism by which aldosterone receptor antagonists improve heart failure morbidity and mortality. The benefits of aldosterone receptor antagonist use in heart failure must be weighed against the potential risk of complications, ie, hyperkalemia and, in the case of spironolactone, possible endocrine abnormalities, in particular gynecomastia. With appropriate monitoring, these risks can be minimized. We now have evidence that patients with mild-to-severe symptoms associated with systolic heart failure will benefit from the addition of an aldosterone receptor antagonist to the standard therapies of angiotensin-converting enzyme inhibitors and beta

  8. Recent Advances in the Development of Undecaprenyl Pyrophosphate Synthase Inhibitors as Potential Antibacterials.

    PubMed

    Jukic, Marko; Rozman, Kaja; Gobec, Stanislav

    2016-01-01

    Expanding antibiotic use in clinical practice and emergence of bacterial resistance are fueling research efforts for the development of novel antibacterials. Underexploited or completely novel mechanistic approaches and biological targets are of especial interest. Undecaprenyl pyrophosphate synthase (UppS) is an essential enzyme in the biosynthesis of the bacterial cell wall. Although UppS is a validated target, no selective inhibitors occur in materia medica. Nevertheless, several native substrate analogues have been reported and used in enzyme kinetics studies or as pharmacological probes. The majority of small-molecule UppS inhibitors belong to the well-known class of bisphosphonates that are primarily used for treatment of bone resorption disorders. The most potent compound of this class has an IC50 of 0.59 µM. Inherently, the selectivity and suitability of such compounds for antimicrobial drug design can be questioned. Therefore, highthroughput and virtual screenings for non-bisphosphonate inhibitors were performed, and nanomolar inhibitors of UppS were identified, some with antimicrobial activities towards clinically relevant strains. The reported scaffolds belong to tetramic and tetronic acids with IC50 in the 100-nM range, and to dihydropyridines with IC50 down to 40 nM, all with antibacterial activity. Aryl-diketo acids are also potent inhibitors with MRSA antimicrobial activity, with the allosteric inhibitor methylisoxazole-4-carboxamide (IC50, 50 nM) active on several pathogenic Streptococcus pneumoniae strains. Clomiphene is a well-known oestrogen receptor modulator, and it has been reported to inhibit UppS. Although conclusions on the structure activity relationships cannot be drawn from all these data, these compound series represent an important contribution to the field of antibiotics. PMID:26718796

  9. Aldosterone and the conquest of land.

    PubMed

    Colombo, L; Dalla Valle, L; Fiore, C; Armanini, D; Belvedere, P

    2006-04-01

    The sequence of the phylogenetic events that preceded the appearance of aldosterone in vertebrates is described, starting from the ancestral conversion of cytochrome P450s from oxygen detoxification to xenobiotic detoxification and synthesis of oxygenated endobiotics with useful functions in intercellular signalling, such as steroid hormones. At the end of the Silurian period [438-408 million yr ago, (Mya)], a complete set of cytochrome P450s for corticoid synthesis was presumably already available, except for mitochondrial cytochrome P450c18 or aldosterone synthase encoded by CYP11B2. This gene arose by duplication of the CYP11B gene in the sarcopterygian or lobe-finned fish/tetrapod line after its divergence from the actinopterygian or ray-finned fish line 420 Mya, but before the beginning of the colonization of land by tetrapods in the late Devonian period, around 370 Mya. The fact that aldosterone is already present in Dipnoi, which occupy an evolutionary transition between water- and air-breathing but are fully aquatic, suggests that the role of this steroid was to potentiate the corticoid response to hypoxia, rather than to prevent dehydration out of the water. In terrestrial amphibians, there is no differentiation between the secretion rates and gluco- and mineralocorticoid effects of aldosterone and corticosterone. In sauropsids, plasma aldosterone concentrations are much lower than in amphibians, but regulation of salt/water balance is dependent upon both aldosterone and corticosterone, though sometimes with opposed actions. In terrestrial mammals, aldosterone acquires a specific mineralocorticoid function, because its interaction with the mineralocorticoid receptor is protected by the coexpression of the enzyme 11beta-hydroxysteroid dehydrogenase type 2, which inactivates both cortisol and corticosterone. There is evidence that aldosterone can be also synthesized extra-adrenally in brain neurons and cardiac myocytes, which lack this protection and where

  10. Multiple resistance of acetolactate synthase and protoporphyrinogen oxidase inhibitors in Euphorbia heterophylla biotypes.

    PubMed

    Trezzi, Michelangelo M; Felippi, C L; Mattei, D; Silva, H L; Nunes, A L; Debastiani, C; Vidal, R A; Marques, A

    2005-01-01

    Resistance to acetolactate synthase (ALS)-inhibiting herbicides in Brazil has been documented for six species. The probability to select biotypes of Euphorbia heterophylla (EPPHL) with multiple resistance increases in the same order of magnitude as the use of other herbicides belonging to only one mechanism of action. The objectives of this work were to evaluate the distribution of resistant populations (R) in the states of the Parana and Santa Catarina; to determine the existence of populations of EPHHL with multiple resistance to ALS and PROTOX inhibitors, and to confirm the occurrence of cross resistance to compounds of these mechanisms of action. Seeds of EPHHL of areas with suspected resistance had been sampled in 97 places during 2003. In the greenhouse experiment samples of each population were sprayed with imazethapyr or fomesafen, at only one rate. To identify the resistant ones they were sprayed with different levels of the herbicides imazethapyr and fomesafen. Later they were sprayed with diverse herbicides of the same mechanisms of action to confirm the multiple/cross resistance. There is widespread distribution in the region of populations with resistance to ALS inhibitors. Some biotypes demonstrated resistance to herbicides from the two mechanisms of action. The resistance factor (FR), or the relation of resistance between R and susceptible biotypes, confirms the existence of two biotypes of EPHHL with cross resistance to several herbicides inhibitors of ALS and PROTOX. PMID:15656167

  11. Quinazolinones, Quinazolinthiones, and Quinazolinimines as Nitric Oxide Synthase Inhibitors: Synthetic Study and Biological Evaluation.

    PubMed

    Camacho, M Encarnación; Chayah, Mariem; García, M Esther; Fernández-Sáez, Nerea; Arias, Fabio; Gallo, Miguel A; Carrión, M Dora

    2016-08-01

    The synthesis of different compounds with a quinazolinone, quinazolinthione, or quinazolinimine skeleton and their in vitro biological evaluation as inhibitors of inducible and neuronal nitric oxide synthase (iNOS and nNOS) isoforms are described. These derivatives were obtained from substituted 2-aminobenzylamines, using diverse cyclization procedures. Furthermore, the diamines were synthesized by two routes: A conventional pathway and an efficient one-pot synthesis in a continuous-flow hydrogenator. The structures of these heterocycles were confirmed by (1) H and (13) C nuclear magnetic resonance and high-resolution mass spectroscopy data. The structure-activity relationships of the target molecules are discussed in terms of the effects of both the R radical and the X heteroatom in the 2-position. In general, the assayed compounds behave as better iNOS than nNOS inhibitors, with the quinazolinone 11e being the most active inhibitor of all tested compounds and the most iNOS/nNOS selective one. PMID:27328401

  12. In silico design, synthesis, and screening of novel deoxyhypusine synthase inhibitors targeting HIV-1 replication.

    PubMed

    Schroeder, Marcus; Kolodzik, Adrian; Pfaff, Katharina; Priyadarshini, Poornima; Krepstakies, Marcel; Hauber, Joachim; Rarey, Matthias; Meier, Chris

    2014-05-01

    The human enzyme deoxyhypusine synthase (DHS) is an important host cell factor that participates in the post-translational hypusine modification of eukaryotic initiation factor 5A (eIF-5A). Hypusine-modified eIF-5A plays a role in a number of diseases, including HIV infection/AIDS. Thus, DHS represents a novel and attractive drug target. So far, four crystal structures are available, and various substances have been tested for inhibition of human DHS. Among these inhibitors, N-1-guanyl-1,7-diaminoheptane (GC7) has been co-crystallized in the active site of DHS. However, despite its potency, GC7 is not selective enough to be used in drug applications. Therefore, new compounds that target DHS are needed. Herein we report the in silico design, chemical synthesis, and biological evaluation of new DHS inhibitors. One of these inhibitors showed dose-dependent inhibition of DHS in vitro, as well as suppression of HIV replication in cell cultures. Furthermore, the compound exhibited no cytotoxic effects at active concentrations. Thus, this designed compound demonstrated proof of principle and represents a promising starting point for the development of new drug candidates to specifically interfere with DHS activity. PMID:24616161

  13. Improvement of dolichol-linked oligosaccharide biosynthesis by the squalene synthase inhibitor zaragozic acid.

    PubMed

    Haeuptle, Micha A; Welti, Michael; Troxler, Heinz; Hülsmeier, Andreas J; Imbach, Timo; Hennet, Thierry

    2011-02-25

    The majority of congenital disorders of glycosylation (CDG) are caused by defects of dolichol (Dol)-linked oligosaccharide assembly, which lead to under-occupancy of N-glycosylation sites. Most mutations encountered in CDG are hypomorphic, thus leaving residual activity to the affected biosynthetic enzymes. We hypothesized that increased cellular levels of Dol-linked substrates might compensate for the low biosynthetic activity and thereby improve the output of protein N-glycosylation in CDG. To this end, we investigated the potential of the squalene synthase inhibitor zaragozic acid A to redirect the flow of the polyisoprene pathway toward Dol by lowering cholesterol biosynthesis. The addition of zaragozic acid A to CDG fibroblasts with a Dol-P-Man synthase defect led to the formation of longer Dol-P species and to increased Dol-P-Man levels. This treatment was shown to decrease the pathologic accumulation of incomplete Dol pyrophosphate-GlcNAc(2)Man(5) in Dol-P-Man synthase-deficient fibroblasts. Zaragozic acid A treatment also decreased the amount of truncated protein N-linked oligosaccharides in these CDG fibroblasts. The increased cellular levels of Dol-P-Man and possibly the decreased cholesterol levels in zaragozic acid A-treated cells also led to increased availability of the glycosylphosphatidylinositol anchor as shown by the elevated cell-surface expression of the CD59 protein. This study shows that manipulation of the cellular Dol pool, as achieved by zaragozic acid A addition, may represent a valuable approach to improve N-linked glycosylation in CDG cells. PMID:21183681

  14. Improvement of Dolichol-linked Oligosaccharide Biosynthesis by the Squalene Synthase Inhibitor Zaragozic Acid*

    PubMed Central

    Haeuptle, Micha A.; Welti, Michael; Troxler, Heinz; Hülsmeier, Andreas J.; Imbach, Timo; Hennet, Thierry

    2011-01-01

    The majority of congenital disorders of glycosylation (CDG) are caused by defects of dolichol (Dol)-linked oligosaccharide assembly, which lead to under-occupancy of N-glycosylation sites. Most mutations encountered in CDG are hypomorphic, thus leaving residual activity to the affected biosynthetic enzymes. We hypothesized that increased cellular levels of Dol-linked substrates might compensate for the low biosynthetic activity and thereby improve the output of protein N-glycosylation in CDG. To this end, we investigated the potential of the squalene synthase inhibitor zaragozic acid A to redirect the flow of the polyisoprene pathway toward Dol by lowering cholesterol biosynthesis. The addition of zaragozic acid A to CDG fibroblasts with a Dol-P-Man synthase defect led to the formation of longer Dol-P species and to increased Dol-P-Man levels. This treatment was shown to decrease the pathologic accumulation of incomplete Dol pyrophosphate-GlcNAc2Man5 in Dol-P-Man synthase-deficient fibroblasts. Zaragozic acid A treatment also decreased the amount of truncated protein N-linked oligosaccharides in these CDG fibroblasts. The increased cellular levels of Dol-P-Man and possibly the decreased cholesterol levels in zaragozic acid A-treated cells also led to increased availability of the glycosylphosphatidylinositol anchor as shown by the elevated cell-surface expression of the CD59 protein. This study shows that manipulation of the cellular Dol pool, as achieved by zaragozic acid A addition, may represent a valuable approach to improve N-linked glycosylation in CDG cells. PMID:21183681

  15. RU28318, an Aldosterone Antagonist, in Combination with an ACE Inhibitor and Angiotensin Receptor Blocker Attenuates Cardiac Dysfunction in Diabetes

    PubMed Central

    Benter, Ibrahim F.; Babiker, Fawzi; Al-Rashdan, Ibrahim; Yousif, Mariam; Akhtar, Saghir

    2013-01-01

    Aims. We evaluated the effects of RU28318 (RU), a selective mineralocorticoid receptor (MR) antagonist, Captopril (Capt), an angiotensin converting enzyme inhibitor, and Losartan (Los), an angiotensin receptor blocker, alone or in combination with ischemia/reperfusion- (I/R-) induced cardiac dysfunction in hearts obtained from normal and diabetic rats. Methods. Isolated hearts were perfused for 30 min and then subjected to 30 min of global ischemia (I) followed by a period of 30 min of reperfusion (R). Drugs were administered for 30 min either before or after ischemia. Drug regimens tested were RU, Capt, Los, RU + Capt, RU + Los, Capt + Los, and RU + Capt + Los (Triple). Recovery of cardiac hemodynamics was evaluated. Results. Recovery of cardiac function was up to 5-fold worse in hearts obtained from diabetic animals compared to controls. Treatment with RU was generally better in preventing or reversing ischemia-induced cardiac dysfunction in normal hearts compared to treatment with Capt or Los alone. In diabetic hearts, RU was generally similarly effective as Capt or Los treatment. Conclusions. RU treatment locally might be considered as an effective therapy or preventative measure in cardiac I/R injury. Importantly, RU was the most effective at improving −dP/dt (a measure of diastolic function) when administered to diabetic hearts after ischemia. PMID:24066305

  16. Enzymatic characterization and inhibitor discovery of a new cystathionine {gamma}-synthase from Helicobacter pylori.

    PubMed

    Kong, Yunhua; Wu, Dalei; Bai, Haiyun; Han, Cong; Chen, Jing; Chen, Lili; Hu, Lihong; Jiang, Hualiang; Shen, Xu

    2008-01-01

    Cystathionine gamma-synthase (CGS) catalyses the first step of the transsulfuration pathway that converts l-cysteine to l-homocysteine in bacteria, whereas this pathway is absent in human. In this report, we identified a new metB gene from Helicobacter pylori strain SS1, and the recombinant H. pylori Cystathionine gamma-synthase (HpCGS) was successfully cloned, expressed and purified in Escherichia coli system. Enzymatic study of HpCGS indicated that the K(m) and k(cat)/K(m) values against the substrate O-succinyl-l-homoserine (l-OSHS) were 3.02 mM and 98.7 M(-)(1)s(-)(1), respectively. Moreover, four natural products (alpha-lapachone, 9-hydroxy-alpha-lapachone, Paulownin and Yangambin, Fig. 1) were discovered to demonstrate inhibitory activities against HpCGS with IC(50) values of 11 +/- 3, 9 +/- 1, 19 +/- 2 and 27 +/- 6 microM, respectively. All these four inhibitors prevent the binding of l-OSHS to HpCGS in a non-competitive fashion. In vitro antibacterial assays further indicated that these four discovered compounds could highly inhibit the growth of H. pylori and exhibited strong inhibitory specificity against H. pylori related to E. coli. PMID:17981822

  17. Competitive inhibition of nitric oxide synthase by p-aminobenzamidine, a serine proteinase inhibitor.

    PubMed

    Venturini, G; Menegatti, E; Ascenzi, P

    1997-03-01

    p-Aminobenzamidine competitively inhibits bovine trypsin, human and bovine thrombin, and human plasmin, all of which act on substrates containing preferentially the L-arginyl side chain at their P1 position. Considering the structural and functional similarity between p-aminobenzamidine and the L-arginyl side chain in trypsin-like serine proteinases, we investigated the interaction of p-aminobenzamidine with mouse brain nitric oxide synthase (NOS), which uses L-arginine as the substrate for generating NO and L-citrulline. p-Aminobenzamidine is a competitive NOS inhibitor (Ki = 1.2 x 10(-4) M, at pH 7.5 and 37.0 degrees C), but not an NO precursor. Therefore, p-aminobenzamidine affects the NO production and the trypsin-like serine proteinase action. PMID:9125158

  18. Application of a High-throughput Fluorescent Acetyltransferase Assay to Identify Inhibitors of Homocitrate Synthase

    PubMed Central

    Bulfer, Stacie L.; McQuade, Thomas J.; Larsen, Martha J.; Trievel, Raymond C.

    2011-01-01

    Homocitrate synthase (HCS) catalyzes the first step of L-lysine biosynthesis in fungi by condensing acetyl-Coenzyme A and 2-oxoglutarate to form 3R-homocitrate and Coenzyme A. Due to its conservation in pathogenic fungi, HCS has been proposed as a candidate for antifungal drug design. Here we report the development and validation of a robust, fluorescent assay for HCS that is amenable to high-throughput screening for inhibitors in vitro. Using this assay, Schizosaccharomyces pombe HCS was screened against a diverse library of ~41,000 small molecules. Following confirmation, counter screens, and dose-response analysis, we prioritized over 100 compounds for further in vitro and in vivo analysis. This assay can be readily adapted to screen for small molecule modulators of other acyl-CoA-dependent acyltransferases or enzymes that generate a product with a free sulfhydryl group, including histone acetyltransferases, aminoglycoside N-acetyltransferases, thioesterases and enzymes involved in lipid metabolism. PMID:21073853

  19. New drug therapies interfering with the renin-angiotensin-aldosterone system for resistant hypertension.

    PubMed

    Monge, Matthieu; Lorthioir, Aurélien; Bobrie, Guillaume; Azizi, Michel

    2013-12-01

    There is a persistent need for the development of new antihypertensive drugs, because the control of blood pressure is still not achievable in a significant proportion of hypertensive patients. Since the approval in 2007 of aliskiren, no other new antihypertensive based on new mechanism(s) of action have been approved. In fact, the development of promising novel drugs has been stopped for safety, efficacy or marketing reasons. Despite these difficulties, the pipeline is not dry and different new antihypertensive strategies targeting the renin-angiotensin-aldosterone pathway, are in clinical development stage. The dual angiotensin II receptor-neprilysin inhibitor LCZ696, a single molecule synthetized by cocrystallisation of valsartan and the neprilysin inhibitor prodrug AHU377 is in development for resistant hypertension and for heart failure. Daglutril is a dual neprylisin-endothelin converting enzyme inhibitor which was shown to decrease BP in patients with type 2 diabetic nephropathy. Aldosterone synthase inhibitors and the third and fourth generation non-steroidal dihydropyridine based mineralocorticoid receptors blockers are new ways to target the multiple noxious effects of aldosterone in the kidney, vessels and heart. Centrally acting aminopeptidase A inhibitors block brain angiotensin III formation, one of the main effector peptides of the brain renin angiotensin system. However, a long time will be still necessary to evaluate extensively the efficacy and safety of these new approaches. In the mean time, using appropriate and personalized daily doses of available drugs, decreasing physician inertia, improving treatment adherence, improving access to healthcare and reducing treatment costs remain major objectives to reduce the incidence of resistant hypertension. PMID:24222656

  20. Evaluation of deoxyhypusine synthase inhibitors targeting BCR-ABL positive leukemias.

    PubMed

    Ziegler, Patrick; Chahoud, Tuhama; Wilhelm, Thomas; Pällman, Nora; Braig, Melanie; Wiehle, Valeska; Ziegler, Susanne; Schröder, Marcus; Meier, Chris; Kolodzik, Adrian; Rarey, Matthias; Panse, Jens; Hauber, Joachim; Balabanov, Stefan; Brümmendorf, Tim H

    2012-12-01

    Effective inhibition of BCR-ABL tyrosine kinase activity with Imatinib represents a breakthrough in the treatment of patients with chronic myeloid leukemia (CML). However, more than 30 % of patients with CML in chronic phase do not respond adequately to Imatinib and the drug seems not to affect the quiescent pool of BCR-ABL positive leukemic stem and progenitor cells. Therefore, despite encouraging clinical results, Imatinib can still not be considered a curative treatment option in CML. We recently reported downregulation of eukaryotic initiation factor 5A (eIF5A) in Imatinib treated K562 cells. Furthermore, the inhibition of eIF5A by siRNA in combination with Imatinib has been shown to exert synergistic cytotoxic effects on BCR-ABL positive cell lines. Based on the structure of known deoxyhypusine synthase (DHS) inhibitors such as CNI-1493, a drug design approach was applied to develop potential compounds targeting DHS. Here we report the biological evaluation of selected novel (DHSI-15) as compared to established (CNI-1493, deoxyspergualin) DHS inhibitors. We show that upon the compounds tested, DHSI-15 and deoxyspergualin exert strongest antiproliferative effects on BCR-ABL cells including Imatinib resistant mutants. However, this effect did not seem to be restricted to BCR-ABL positive cell lines or primary cells. Both compounds are able to induce apoptosis/necrosis during long term incubation of BCR-ABL positive BA/F3 derivates. Pharmacological synergism can be observed for deoxyspergualin and Imatinib, but not for DHSI-15 and Imatinib. Finally we show that deoxyspergualin is able to inhibit proliferation of CD34+ progenitor cells from CML patients. We conclude that inhibition of deoxyhypusine synthase (DHS) can be supportive for the anti-proliferative treatment of leukemia and merits further investigation including other cancers. PMID:22415796

  1. The renin-angiotensin-aldosterone system and its blockade in diabetic nephropathy: main focus on the role of aldosterone.

    PubMed

    Schjoedt, Katrine Jordan

    2011-04-01

    Diabetic nephropathy is the most common cause of end-stage renal disease in the western world. Despite major improvements in both prevention and treatment of diabetic nephropathy, there is a continuous need to improve identification and treatment of "non-responders". In recent years, several experimental studies have shown that aldosterone plays a role in the development and progression of diabetic nephropathy, independent of angiotensin II and blood pressure levels. Blocking the renin-angiotensin-aldosterone system with an ACE-inhibitor (ACEI) and/or ambulatory blood pressure should theoretically inhibit the secretion of aldosterone. However, an increase in aldosterone during long-term treatment with ACEIs, so-called aldosterone escape or aldosterone breakthrough, has been described. In the present thesis, our studies evaluating the incidence and clinical impact (i.e. a faster rate of decline in kidney function) of aldosterone escape in type 1 diabetic patients with diabetic nephropathy, possible mechanisms of aldosterone escape, and finally the beneficial effect of blocking aldosterone on albuminuria, blood pressure and renal autoregulation is being reviewed, together with some aspects of the existing treatment recommendations. PMID:21466768

  2. Role of glycogen synthase kinase-3β inhibitor AZD1080 in ovarian cancer

    PubMed Central

    Chen, Shuo; Sun, Kai-Xuan; Feng, Miao-Xiao; Sang, Xiu-Bo; Liu, Bo-Liang; Zhao, Yang

    2016-01-01

    Background Glycogen synthase kinase-3β (GSK-3β) is a multifunctional serine/threonine kinase that plays an important role in cancer tumorigenesis and progression. We investigated the role of the GSK-3β inhibitor AZD1080 in ovarian cancer cell lines. Methods A2780 and OVCAR3 ovarian cancer cell lines were exposed to AZD1080, after which cell proliferation, cell cycle, invasion, and migration assays were performed. Phalloidin staining was used to observe lamellipodia formation. Reverse transcription polymerase chain reaction and Western blot were used to assess the respective mRNA and protein expression levels of GSK-3β, CDK2, CDK1, cyclin D1, matrix metalloproteinase-9 (MMP9), and Bcl-xL. Results AZD1080 exposure suppressed ovarian cancer cell proliferation, invasion, migration, and lamellipodia formation, and induced G1 arrest, which was concentration dependent. AZD1080 also significantly downregulated GSK-3β, CDK2, CDK1, cyclin D1, MMP9, and Bcl-xL expression at both mRNA and protein levels. Conclusion Taken together, our results demonstrate that the GSK-3β inhibitor AZD1080 suppresses ovarian cancer development and therefore may indicate a new direction for ovarian cancer treatment. PMID:27051274

  3. Effects of the inducible nitric oxide synthase inhibitor aminoguanidine in two different rat models of schizophrenia.

    PubMed

    Lafioniatis, Anastasios; Orfanidou, Martha A; Papadopoulou, Evangelia S; Pitsikas, Nikolaos

    2016-08-01

    Several lines evidence indicate that the non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist ketamine and the mixed dopamine (DA) D1/D2 receptor agonist apomorphine induce schizophrenia-like symptoms in rodents, including memory impairments and social withdrawal. Nitric oxide (NO) has been proposed to act as an intracellular messenger in the brain and its overproduction is associated with schizophrenia. The current study was designed to investigate the ability of the inducible NO synthase (iNOS) inhibitor aminoguanidine (AG) to counteract schizophrenia-like behavioural deficits produced by ketamine and apomorphine in rats. The efficacy of AG to antagonize extinction of recognition memory, ketamine and apomorphine-induced recognition memory impairments was tested utilizing the novel object recognition task (NORT). Further, the efficacy of AG to attenuate ketamine-induced social withdrawal was examined in the social interaction test. AG (25 and 50mg/kg) antagonized extinction of recognition memory and reversed ketamine (3mg/kg) and apomorphine (1mg/kg)-induced recognition memory deficits. In contrast, AG (50 and 100mg/kg) did not counteract the ketamine (8mg/kg)-induced social isolation. The present data show that the iNOS inhibitor AG counteracted extinction of recognition memory and reversed recognition memory deficits produced by dysfunction of the glutamatergic and the dopaminergic (DAergic) system in rats. Therefore, AG may be efficacious in attenuating memory impairments often observed in schizophrenia patients. PMID:27132765

  4. Discovery of Highly Potent and Selective Inhibitors of Neuronal Nitric Oxide Synthase by Fragment Hopping

    PubMed Central

    Ji, Haitao; Li, Huiying; Martásek, Pavel; Roman, Linda J.; Poulos, Thomas L.; Silverman, Richard B.

    2009-01-01

    Selective inhibition of neuronal nitric oxide synthase (nNOS) has been shown to prevent brain injury and is important for the treatment of various neurodegenerative disorders. This study shows that not only greater inhibitory potency and isozyme selectivity, but more drug-like properties can be achieved by fragment hopping. Based on the structure of lead molecule 6, fragment hopping effectively extracted the minimal pharmacophoric elements in the active site of nNOS for ligand hydrophobic and steric interactions and generated appropriate lipophilic fragments for lead optimization. More potent and selective inhibitors with better drug-like properties were obtained within the design of 20 derivatives (compounds 7-26). Our structure-based inhibitor design for nNOS and SAR analysis reveal the robustness and efficiency of fragment hopping in lead discovery and structural optimization, which implicates a broad application of this approach to many other therapeutic targets for which known drug-like small-molecule modulators are still limited. PMID:19125620

  5. Molecular Docking Analysis of Selected Clinacanthus nutans Constituents as Xanthine Oxidase, Nitric Oxide Synthase, Human Neutrophil Elastase, Matrix Metalloproteinase 2, Matrix Metalloproteinase 9 and Squalene Synthase Inhibitors

    PubMed Central

    Narayanaswamy, Radhakrishnan; Isha, Azizul; Wai, Lam Kok; Ismail, Intan Safinar

    2016-01-01

    Background: Clinacanthus nutans (Burm. f.) Lindau has gained popularity among Malaysians as a traditional plant for anti-inflammatory activity. Objective: This prompted us to carry out the present study on a selected 11 constituents of C. nutans which are clinacoside A–C, cycloclinacoside A1, shaftoside, vitexin, orientin, isovitexin, isoorientin, lupeol and β-sitosterol. Materials and Methods: Selected 11 constituents of C. nutans were evaluated on the docking behavior of xanthine oxidase (XO), nitric oxide synthase (NOS), human neutrophil elastase (HNE), matrix metalloproteinase (MMP 2 and 9), and squalene synthase (SQS) using Discovery Studio Version 3.1. Also, molecular physicochemical, bioactivity, absorption, distribution, metabolism, excretion, and toxicity (ADMET), and toxicity prediction by computer assisted technology analyzes were also carried out. Results: The molecular physicochemical analysis revealed that four ligands, namely clinacoside A–C and cycloclinacoside A1 showed nil violations and complied with Lipinski's rule of five. As for the analysis of bioactivity, all the 11 selected constituents of C. nutans exhibited active score (>0) toward enzyme inhibitors descriptor. ADMET analysis showed that the ligands except orientin and isoorientin were predicted to have Cytochrome P4502D6 inhibition effect. Docking studies and binding free energy calculations revealed that clinacoside B exhibited the least binding energy for the target enzymes except for XO and SQS. Isovitexin and isoorientin showed the potentials in the docking and binding with all of the six targeted enzymes, whereas vitexin and orientin docked and bound with only NOS and HNE. Conclusion: This present study has paved a new insight in understanding these 11 C. nutans ligands as potential inhibitors against XO, NOS, HNE, MMP 2, MMP 9, and SQS. SUMMARY Isovitexin and isoorientin (Clinacanthus nutans constituent) showed potentials in the docking and binding with all of the six targeted

  6. Effect and mechanism of poly (ADP-ribose) polymerase-1 in aldosterone-induced apoptosis

    PubMed Central

    QIAO, WEIWEI; ZHANG, WEILI; SHAO, SHUHONG; GAI, YUSHENG; ZHANG, MINGXIANG

    2015-01-01

    The present study aimed to investigate the effects of aldosterone on vascular endothelial cells and the viability of poly (ADP-ribose) polymerase 1 (PARP1) in cells, and to examine the molecular mechanisms underlying the effects of aldosterone on vascular endothelial cell injury. Cultured endothelial cells were treated either with different concentrations of aldosterone for the same duration or with the same concentrations of aldosterone for different durations, and the levels of apoptosis and activity of PARP1 in the cells were detected, respectively. Aldosterone receptor antagonists or PARP1 inhibitors were added to cells during treatment with aldosterone and the levels of apoptosis and activity of PARP1 were detected. As the concentration of aldosterone increased or the treatment time increased, the number of apoptotic cells and the activity of PARP1 increased. The aldosterone receptor antagonists and PARP1 inhibitors inhibited the increase of apoptosis and PARP1 activity caused by aldosterone treatment. Aldosterone activated the activity of PARP1 via the aldosterone receptor, inhibiting cell proliferation and inducing apoptosis. Treatment with PARP1 may be used as a target for vascular diseases caused by aldosterone at high concentrations. PMID:25872931

  7. Synthesis and biological evaluation of several dephosphonated analogues of CMP-Neu5Ac as inhibitors of GM3-synthase.

    PubMed

    Rota, Paola; Cirillo, Federica; Piccoli, Marco; Gregorio, Antonio; Tettamanti, Guido; Allevi, Pietro; Anastasia, Luigi

    2015-10-01

    Previous studies demonstrated that reducing the GM3 content in myoblasts increased the cell resistance to hypoxic stress, suggesting that a pharmacological inhibition of the GM3 synthesis could be instrumental for the development of new treatments for ischemic diseases. Herein, the synthesis of several dephosphonated CMP-Neu5Ac congeners and their anti-GM3-synthase activity is reported. Biological activity testes revealed that some inhibitors almost completely blocked the GM3-synthase activity in vitro and reduced the GM3 content in living embryonic kidney 293A cells, eventually activating the epidermal growth factor receptor (EGFR) signaling cascade. PMID:26397189

  8. P21Cip1 is a critical mediator of the cytotoxic action of thymidylate synthase inhibitors in colorectal carcinoma cells.

    PubMed

    Geller, James I; Szekely-Szucs, Kinga; Petak, Istvan; Doyle, Belinda; Houghton, Janet A

    2004-09-01

    We have demonstrated previously that interferon (IFN)-gamma sensitizes human colon carcinoma cell lines to the cytotoxic effects of 5-fluorouracil combined with leucovorin and to the thymidylate synthase inhibitor, ZD9331, dependent on thymineless stress-induced DNA damage, independent of p53. Here we demonstrate that the cyclin-dependent kinase (CDK) inhibitor p21(Cip1) regulates thymineless stress-induced cytotoxicity in these cells. HCT116 wild-type (wt) and p53-/- cells underwent apoptosis and loss in clonogenic survival when exposed to ZD9331, whereas p21Cip1-/- cells were resistant. In contrast, IFN-gamma induced marked cytotoxicity in p21Cip1-/- cells only. ZD9331 induced p21Cip1 up-regulation in all of the cell lines examined, as did thymidine deprivation in thymidylate synthase-deficient (thymidylate synthase-) cells. Furthermore, selective induction of p21Cip1 in RKO was sufficient to induce apoptosis. P21Cip1, cdk1, cdk2, and cyclin E mRNA expression increased coincident with S-phase accumulation in HT29 cells treated with ZD9331 or 5fluorouracil/leucovorin, as demonstrated by cDNA microarray analyses. Cell cycle analyses revealed that HCT116 wt and p21Cip1 -/- cells accumulated in S phase within 24 h of ZD9331 exposure; however, wt cells exited S-phase more rapidly, where apoptosis occurred before mitosis, either in late S or G2. Finally, the CDK inhibitor roscovitine potentiated the cytotoxic activity of ZD9331 in both wt and p21Cip1-/- cells, strongly suggesting a role for p21Cip1-dependent CDK inhibition in cytotoxicity induced by thymidylate synthase inhibition. In summary, p21Cip1 positively regulates the cytotoxic action of thymidylate synthase inhibitors, negatively regulates the cytotoxic action of IFN-gamma, and enhances S-phase exit after thymineless stress, possibly via interaction with CDK-cyclin complexes. PMID:15342418

  9. In vivo study of radioprotective effect of NO-synthase inhibitors and acetyl-L-carnitine.

    PubMed

    Babicová, A; Havlínová, Z; Hroch, M; Rezáčová, M; Pejchal, J; Vávrová, J; Chládek, J

    2013-01-01

    This study investigated the protective effect of two nitric oxide synthase inhibitors N(omega)-nitro-L-arginine methyl ester (L-NAME, 100 mg/kg i.p.) and aminoguanidine (AG, 400 mg/kg i.p.), and an antioxidant acetyl-L-carnitine (ALC, 250 mg/kg i.p., once daily for five days) against radiation-induced damage in Wistar rats. Blood samples were collected 6 h after whole-body irradiation with 8 Gy. Plasma concentrations of nitrite+nitrate (NO(x)) and malondialdehyde (MDA) were measured by high-performance liquid chromatography. A single injection of L-NAME one hour before exposure effectively prevented the radiation-induced elevation of plasma NO(x) and it reduced 2.6-fold the risk for death during the subsequent 30-day period. Pretreatment with ALC prevented the radiation-induced increase in plasma MDA and it had similar effect on mortality as L-NAME did. Presumably due to its short half-life, the partially iNOS-selective inhibitor and antioxidant AG given in a single dose before exposure did not attenuate MDA and NO(x) and it failed to significantly improve the 30-day survival. In conclusion, pretreatment with both the nonspecific NOS inhibitor L-NAME and the antioxidant ALC markedly reduce mortality to radiation sickness in rats. The radioprotective effect may be directly related to effective attenuation of the radiation-induced elevation of NO production by L-NAME and of oxidative stress by ALC. PMID:23869893

  10. Hybrid inhibitor of peripheral cannabinoid-1 receptors and inducible nitric oxide synthase mitigates liver fibrosis

    PubMed Central

    Liu, Ziyi; Cao, Zongxian; Jourdan, Tony; Erdelyi, Katalin; Godlewski, Grzegorz; Szanda, Gergő; Liu, Jie; Park, Joshua K.; Mukhopadhyay, Bani; Rosenberg, Avi Z.; Liow, Jeih-San; Lorenz, Robin G.; Pacher, Pal; Innis, Robert B.; Kunos, George

    2016-01-01

    Liver fibrosis, a consequence of chronic liver injury and a way station to cirrhosis and hepatocellular carcinoma, lacks effective treatment. Endocannabinoids acting via cannabinoid-1 receptors (CB1R) induce profibrotic gene expression and promote pathologies that predispose to liver fibrosis. CB1R antagonists produce opposite effects, but their therapeutic development was halted due to neuropsychiatric side effects. Inducible nitric oxide synthase (iNOS) also promotes liver fibrosis and its underlying pathologies, but iNOS inhibitors tested to date showed limited therapeutic efficacy in inflammatory diseases. Here, we introduce a peripherally restricted, orally bioavailable CB1R antagonist, which accumulates in liver to release an iNOS inhibitory leaving group. In mouse models of fibrosis induced by CCl4 or bile duct ligation, the hybrid CB1R/iNOS antagonist surpassed the antifibrotic efficacy of the CB1R antagonist rimonabant or the iNOS inhibitor 1400W, without inducing anxiety-like behaviors or CB1R occupancy in the CNS. The hybrid inhibitor also targeted CB1R-independent, iNOS-mediated profibrotic pathways, including increased PDGF, Nlrp3/Asc3, and integrin αvβ6 signaling, as judged by its ability to inhibit these pathways in cnr1−/− but not in nos2−/− mice. Additionally, it was able to slow fibrosis progression and to attenuate established fibrosis. Thus, dual-target peripheral CB1R/iNOS antagonists have therapeutic potential in liver fibrosis. PMID:27525312

  11. Farnesyl pyrophosphate synthase inhibitor, ibandronate, improves endothelial function in spontaneously hypertensive rats.

    PubMed

    Han, Jie; Jiang, Dong-Mei; Ye, Yang; Du, Chang-Qing; Yang, Jian; Hu, Shen-Jiang

    2016-05-01

    Reactive oxygen species (ROS), originating predominantly from vascular smooth muscle cells (VSMCs), lead to vascular damage and endothelial dysfunction in rats with hypertension. The downstream signaling pathways of farnesyl pyrophosphate (FPP) synthase, Ras-related C3 botulinum toxin substrate 1 (Rac1) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, mediate the generation of ROS. The present study investigated the effect of the FPP synthase inhibitor, ibandronate, on ROS production, the possible beneficial effect on endothelial dysfunction and the underlying mechanisms in spontaneously hypertensive rats (SHRs). The SHRs were treated with ibandronate for 30 days. Endothelium‑dependent and independent vasorelaxation were measured in isolated aortic rings. Additionally, VSMCs from the SHRs and Wistar‑Kyoto (WKY) rats were cultured. The production of ROS and activation of NADPH oxidase were determined using fluorescence and chemiluminescence, respectively, in vivo and in vitro. Angiotensin II (Ang II) increased ROS production in the cultured VSMCs from the WKY rats and SHRs, in a concentration‑dependent manner. The Ang II‑induced responses were more marked in the SHR VSMCs, compare with those in the WKY VSMCs, however, the response decreased significantly following ibandronate pretreatment. Treatment with ibandronate significantly decreased the production of ROS, translocation of NADPH oxidase subunit p47phox, and activities of NADPH oxidase and Rac1 in the aorta and VSMCs, and improved the impaired endothelium‑dependent vasodilation in the SHRs. Adding geranylgeraniol, but not farnesol or mevalonate, reversed the inhibitory effects of ibandronate. In addition, inhibiting geranylgeranyl-transferase mimicked the effect of ibandronate on the excess oxidative response. Ibandronate exerted cellular antioxidant effects through the Rac1/NADPH oxidase pathway. These effects may have contributed to the vasoprotective effects on the impaired

  12. Farnesyl pyrophosphate synthase inhibitor, ibandronate, improves endothelial function in spontaneously hypertensive rats

    PubMed Central

    HAN, JIE; JIANG, DONG-MEI; YE, YANG; DU, CHANG-QING; YANG, JIAN; HU, SHEN-JIANG

    2016-01-01

    Reactive oxygen species (ROS), originating predominantly from vascular smooth muscle cells (VSMCs), lead to vascular damage and endothelial dysfunction in rats with hypertension. The downstream signaling pathways of farnesyl pyrophosphate (FPP) synthase, Ras-related C3 botulinum toxin substrate 1 (Rac1) and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, mediate the generation of ROS. The present study investigated the effect of the FPP synthase inhibitor, ibandronate, on ROS production, the possible beneficial effect on endothelial dysfunction and the underlying mechanisms in spontaneously hypertensive rats (SHRs). The SHRs were treated with ibandronate for 30 days. Endothelium-dependent and independent vasorelaxation were measured in isolated aortic rings. Additionally, VSMCs from the SHRs and Wistar-Kyoto (WKY) rats were cultured. The production of ROS and activation of NADPH oxidase were determined using fluorescence and chemiluminescence, respectively, in vivo and in vitro. Angiotensin II (Ang II) increased ROS production in the cultured VSMCs from the WKY rats and SHRs, in a concentration-dependent manner. The Ang II-induced responses were more marked in the SHR VSMCs, compare with those in the WKY VSMCs, however, the response decreased significantly following ibandronate pretreatment. Treatment with ibandronate significantly decreased the production of ROS, translocation of NADPH oxidase subunit p47phox, and activities of NADPH oxidase and Rac1 in the aorta and VSMCs, and improved the impaired endothelium-dependent vasodilation in the SHRs. Adding geranylgeraniol, but not farnesol or mevalonate, reversed the inhibitory effects of ibandronate. In addition, inhibiting geranylgeranyl-transferase mimicked the effect of ibandronate on the excess oxidative response. Ibandronate exerted cellular antioxidant effects through the Rac1/NADPH oxidase pathway. These effects may have contributed to the vasoprotective effects on the impaired endothelium in

  13. Induction by inhibitors of nitric oxide synthase of hyperresponsiveness in the human nasal airway

    PubMed Central

    Turner, P J; Maggs, J R L; Foreman, J C

    2000-01-01

    The effects of inhibitors of nitric oxide synthase (NOS) on the responsiveness of the human nasal airway were investigated, by measuring the nasal response to histamine and bradykinin. Repeated intranasal administration of NG-nitro-L-arginine methyl ester (L-NAME) or NG-monomethyl-L-arginine (L-NMMA), 1 μmol per nostril every 30 min for 6 h, increased the nasal obstruction induced by histamine, 50–500 μg, and bradykinin, 200 μg per nostril. A single administration of L-NAME, 1 μmol per nostril did not induce hyperresponsiveness to histamine. Pretreatment with L-arginine, 30 μmol, abolished the hyperresponsiveness to histamine caused by L-NAME, 1 μmol. Pretreatment with NG-nitro-D-arginine methyl ester (D-NAME), 1 μmol, did not induce hyperresponsiveness to histamine. Repeated administration of L-NAME, 1 μmol, caused a significant reduction in the amount of nitric oxide measured in the nasal cavity. Neither L-NMMA, 1 μmol, nor L-arginine, 30 μmol, altered the nasal hyperresponsiveness induced by platelet activating factor (PAF), 60 μg. PAF did not alter the levels of nitric oxide in the nasal cavity. The results suggest that inhibition of nitric oxide synthase induces a hyperresponsiveness in the human nasal airway, and that this occurs by a mechanism different from that involved in PAF-induced hyperresponsiveness. PMID:10991932

  14. Non-antibiotic quorum sensing inhibitors acting against N-acyl homoserine lactone synthase as druggable target

    PubMed Central

    Chang, Chien-Yi; Krishnan, Thiba; Wang, Hao; Chen, Ye; Yin, Wai-Fong; Chong, Yee-Meng; Tan, Li Ying; Chong, Teik Min; Chan, Kok-Gan

    2014-01-01

    N-acylhomoserine lactone (AHL)-based quorum sensing (QS) is important for the regulation of proteobacterial virulence determinants. Thus, the inhibition of AHL synthases offers non-antibiotics-based therapeutic potentials against QS-mediated bacterial infections. In this work, functional AHL synthases of Pseudomonas aeruginosa LasI and RhlI were heterologously expressed in an AHL-negative Escherichia coli followed by assessments on their AHLs production using AHL biosensors and high resolution liquid chromatography–mass spectrometry (LCMS). These AHL-producing E. coli served as tools for screening AHL synthase inhibitors. Based on a campaign of screening synthetic molecules and natural products using our approach, three strongest inhibitors namely are salicylic acid, tannic acid and trans-cinnamaldehyde have been identified. LCMS analysis further confirmed tannic acid and trans-cinnemaldehyde efficiently inhibited AHL production by RhlI. We further demonstrated the application of trans-cinnemaldehyde inhibiting Rhl QS system regulated pyocyanin production in P. aeruginosa up to 42.06%. Molecular docking analysis suggested that trans-cinnemaldehyde binds to the LasI and EsaI with known structures mainly interacting with their substrate binding sites. Our data suggested a new class of QS-inhibiting agents from natural products targeting AHL synthase and provided a potential approach for facilitating the discovery of anti-QS signal synthesis as basis of novel anti-infective approach. PMID:25430794

  15. Identification of a Glycogen Synthase Kinase-3[beta] Inhibitor that Attenuates Hyperactivity in CLOCK Mutant Mice

    SciTech Connect

    Kozikowski, Alan P.; Gunosewoyo, Hendra; Guo, Songpo; Gaisina, Irina N.; Walter, Richard L.; Ketcherside, Ariel; McClung, Colleen A.; Mesecar, Andrew D.; Caldarone, Barbara

    2012-05-02

    Bipolar disorder is characterized by a cycle of mania and depression, which affects approximately 5 million people in the United States. Current treatment regimes include the so-called 'mood-stabilizing drugs', such as lithium and valproate that are relatively dated drugs with various known side effects. Glycogen synthase kinase-3{beta} (GSK-3{beta}) plays a central role in regulating circadian rhythms, and lithium is known to be a direct inhibitor of GSK-3{beta}. We designed a series of second generation benzofuran-3-yl-(indol-3-yl)maleimides containing a piperidine ring that possess IC{sub 50} values in the range of 4 to 680 nM against human GSK-3{beta}. One of these compounds exhibits reasonable kinase selectivity and promising preliminary absorption, distribution, metabolism, and excretion (ADME) data. The administration of this compound at doses of 10 to 25 mg kg{sup -1} resulted in the attenuation of hyperactivity in amphetamine/chlordiazepoxide-induced manic-like mice together with enhancement of prepulse inhibition, similar to the effects found for valproate (400 mg kg{sup -1}) and the antipsychotic haloperidol (1 mg kg{sup -1}). We also tested this compound in mice carrying a mutation in the central transcriptional activator of molecular rhythms, the CLOCK gene, and found that the same compound attenuates locomotor hyperactivity in response to novelty. This study further demonstrates the use of inhibitors of GSK-3{beta} in the treatment of manic episodes of bipolar/mood disorders, thus further validating GSK-3{beta} as a relevant therapeutic target in the identification of new therapies for bipolar patients.

  16. Identification of a Glycogen Synthase Kinase-3β Inhibitor that Attenuates Hyperactivity in CLOCK Mutant Mice

    PubMed Central

    Kozikowski, Alan P.; Gunosewoyo, Hendra; Guo, Songpo; Gaisina, Irina N.; Walter, Richard L.; Ketcherside, Ariel; McClung, Colleen A.; Mesecar, Andrew D.; Caldarone, Barbara

    2012-01-01

    Bipolar disorder is characterized by a cycle of mania and depression, which affects approximately 5 million people in the United States. Current treatment regimes include the so-called “mood-stabilizing drugs”, such as lithium and valproate that are relatively dated drugs with various known side effects. Glycogen synthase kinase-3β (GSK-3β) plays a central role in regulating circadian rhythms, and lithium is known to be a direct inhibitor of GSK-3β. We designed a series of second generation benzofuran-3-yl-(indol-3-yl)maleimides containing a piperidine ring that possess IC50 values in the range of 4 to 680 nm against human GSK-3β. One of these compounds exhibits reasonable kinase selectivity and promising preliminary absorption, distribution, metabolism, and excretion (ADME) data. The administration of this compound at doses of 10 to 25 mgkg−1 resulted in the attenuation of hyperactivity in amphetamine/ chlordiazepoxide-induced manic-like mice together with enhancement of prepulse inhibition, similar to the effects found for valproate (400 mgkg−1) and the antipsychotic haloperidol (1 mgkg−1). We also tested this compound in mice carrying a mutation in the central transcriptional activator of molecular rhythms, the CLOCK gene, and found that the same compound attenuates locomotor hyperactivity in response to novelty. This study further demonstrates the use of inhibitors of GSK-3β in the treatment of manic episodes of bipolar/mood disorders, thus further validating GSK-3β as a relevant therapeutic target in the identification of new therapies for bipolar patients. PMID:21732538

  17. Quinazoline thymidylate synthase inhibitors: methods for assessing the contribution of polyglutamation to their in vitro activity.

    PubMed

    Jackman, A L; Kimbell, R; Brown, M; Brunton, L; Boyle, F T

    1995-10-01

    Many quinazoline thymidylate synthase (TS) inhibitors undergo intracellular metabolism to polyglutamate forms which can significantly alter their activity and pharmacodynamics through improved TS inhibition and drug retention. When a series of quinazolines was tested for inhibitory activity towards TS (IC50 0.001-2 microM) and the growth of L1210 cells (IC50 0.005-10 microM), no direct correlation was observed. However, a very good correlation was apparent if a L1210 variant cell line (L1210: RD1694) was used. This line is deficient in its ability to form antifolate polyglutamates. A number of other intact cell methods have also been developed which estimate the contribution that intracellular polyglutamation makes to a compound's activity. These assays were validated using a series of quinazoline-based TS inhibitors with well-defined activity for TS, folypolyglutamate synthetase (FPGS) and the reduced-folate cell membrane carrier (RFC). Short-exposure growth-inhibition assays or the measurement of TS activity in situ after various incubation times, followed by different lengths of time in drug-free medium, can indicate both the speed and extent of appearance of retentive forms (usually polyglutamates). Continuous-exposure growth-inhibition assays, in the presence of leucovorin (LV), are also useful, since only the growth-inhibitory potency of polyglutamated analogues is significantly decreased by LV. Highly polyglutamated compounds, e.g. ZD1694, are virtually inactive in the presence of a high concentration of LV. It is proposed that these methods, when considered together, provide a greater degree of information concerning the rate and extent of polyglutamation of a particular compound than isolated FPGS assays alone. PMID:7495479

  18. Synthesis of novel beta-lactone inhibitors of fatty acid synthase.

    PubMed

    Richardson, Robyn D; Ma, Gil; Oyola, Yatsandra; Zancanella, Manuel; Knowles, Lynn M; Cieplak, Piotr; Romo, Daniel; Smith, Jeffrey W

    2008-09-11

    Fatty acid synthase (FAS) is necessary for growth and survival of tumor cells and is a promising drug target for oncology. Here, we report on the syntheses and activity of novel inhibitors of the thioesterase domain of FAS. Using the structure of orlistat as a starting point, which contains a beta-lactone as the central pharmacophore, 28 novel congeners were synthesized and examined. Structural features such as the length of the alpha- and beta-alkyl chains, their chemical composition, and amino ester substitutions were altered and the resulting compounds explored for inhibitory activity toward the thioesterase domain of FAS. Nineteen congeners show improved potency for FAS in biochemical assays relative to orlistat. Three of that subset, including the natural product valilactone, also display an increased potency in inducing tumor cell death and improved solubility compared to orlistat. These findings support the idea that an orlistat congener can be optimized for use in a preclinical drug design and for clinical drug development. PMID:18710210

  19. Synthesis of Novel β-Lactone Inhibitors of Fatty Acid Synthase

    PubMed Central

    Richardson, Robyn D.; Ma, Gil; Oyola, Yatsandra; Zancanella, Manuel; Knowles, Lynn M.; Cieplak, Piotr; Romo, Daniel; Smith, Jeffrey W.

    2011-01-01

    Fatty acid synthase (FAS) is necessary for growth and survival of tumor cells and is a promising drug target for oncology. Here, we report on the syntheses and activity of novel inhibitors of the thioesterase domain of FAS. Using the structure of orlistat as a starting point, which contains a β-lactone as the central pharmacophore, 28 novel congeners were synthesized and examined. Structural features such as the length of the α- and β-alkyl chains, their chemical composition, and amino ester substitutions were altered and the resulting compounds explored for inhibitory activity toward the thioesterase domain of FAS. Nineteen congeners show improved potency for FAS in biochemical assays relative to orlistat. Three of that subset, including the natural product valilactone, also display an increased potency in inducing tumor cell death and improved solubility compared to orlistat. These findings support the idea that an orlistat congener can be optimized for use in a preclinical drug design and for clinical drug development. PMID:18710210

  20. CNS-accessible Inhibitor of Glucosylceramide Synthase for Substrate Reduction Therapy of Neuronopathic Gaucher Disease

    PubMed Central

    Marshall, John; Sun, Ying; Bangari, Dinesh S; Budman, Eva; Park, Hyejung; Nietupski, Jennifer B; Allaire, Amy; Cromwell, Mary A; Wang, Bing; Grabowski, Gregory A; Leonard, John P; Cheng, Seng H

    2016-01-01

    Gaucher disease (GD) is caused by a deficiency of glucocerebrosidase and the consequent lysosomal accumulation of unmetabolized glycolipid substrates. Enzyme-replacement therapy adequately manages the visceral manifestations of nonneuronopathic type-1 Gaucher patients, but not the brain disease in neuronopathic types 2 and 3 GD. Substrate reduction therapy through inhibition of glucosylceramide synthase (GCS) has also been shown to effectively treat the visceral disease. Here, we evaluated the efficacy of a novel small molecule inhibitor of GCS with central nervous system (CNS) access (Genz-682452) to treat the brain disease. Treatment of the conduritol β epoxide-induced mouse model of neuronopathic GD with Genz-682452 reduced the accumulation of liver and brain glycolipids (>70% and >20% respectively), extent of gliosis, and severity of ataxia. In the genetic 4L;C* mouse model, Genz-682452 reduced the levels of substrate in the brain by >40%, the extent of gliosis, and paresis. Importantly, Genz-682452-treated 4L;C* mice also exhibited an ~30% increase in lifespan. Together, these data indicate that an orally available antagonist of GCS that has CNS access is effective at attenuating several of the neuropathologic and behavioral manifestations associated with mouse models of neuronopathic GD. Therefore, Genz-682452 holds promise as a potential therapeutic approach for patients with type-3 GD. PMID:26948439

  1. Linker-Region Modified Derivatives of the Deoxyhypusine Synthase Inhibitor CNI-1493 Suppress HIV-1 Replication.

    PubMed

    Schröder, Marcus; Kolodzik, Adrian; Windshügel, Björn; Krepstakies, Marcel; Priyadarshini, Poornima; Hartjen, Philip; van Lunzen, Jan; Rarey, Matthias; Hauber, Joachim; Meier, Chris

    2016-02-01

    The inhibition of cellular factors that are involved in viral replication may be an important alternative to the commonly used strategy of targeting viral enzymes. The guanylhydrazone CNI-1493, a potent inhibitor of the deoxyhypusine synthase (DHS), prevents the activation of the cellular factor eIF-5A and thereby suppresses HIV replication and a number of other diseases. Here, we report on the design, synthesis and biological evaluation of a series of CNI-1493 analogues. The sebacoyl linker in CNI-1493 was replaced by different alkyl or aryl dicarboxylic acids. Most of the tested derivatives suppress HIV-1 replication efficiently in a dose-dependent manner without showing toxic side effects. The unexpected antiviral activity of the rigid derivatives point to a second binding mode as previously assumed for CNI-1493. Moreover, the chemical stability of CNI-1493 was analysed, showing a successive hydrolysis of the imino bonds. By molecular dynamics simulations, the behaviour of the parent CNI-1493 in solution and its interactions with DHS were investigated. PMID:26725082

  2. Discovery and Characterization of 2-Acylaminoimidazole Microsomal Prostaglandin E Synthase-1 Inhibitors.

    PubMed

    Schiffler, Matthew A; Antonysamy, Stephen; Bhattachar, Shobha N; Campanale, Kristina M; Chandrasekhar, Srinivasan; Condon, Bradley; Desai, Prashant V; Fisher, Matthew J; Groshong, Christopher; Harvey, Anita; Hickey, Michael J; Hughes, Norman E; Jones, Scott A; Kim, Euibong J; Kuklish, Steven L; Luz, John G; Norman, Bryan H; Rathmell, Richard E; Rizzo, John R; Seng, Thomas W; Thibodeaux, Stefan J; Woods, Timothy A; York, Jeremy S; Yu, Xiao-Peng

    2016-01-14

    As part of a program aimed at the discovery of antinociceptive therapy for inflammatory conditions, a screening hit was found to inhibit microsomal prostaglandin E synthase-1 (mPGES-1) with an IC50 of 17.4 μM. Structural information was used to improve enzyme potency by over 1000-fold. Addition of an appropriate substituent alleviated time-dependent cytochrome P450 3A4 (CYP3A4) inhibition. Further structure-activity relationship (SAR) studies led to 8, which had desirable potency (IC50 = 12 nM in an ex vivo human whole blood (HWB) assay) and absorption, distribution, metabolism, and excretion (ADME) properties. Studies on the formulation of 8 identified 8·H3PO4 as suitable for clinical development. Omission of a lipophilic portion of the compound led to 26, a readily orally bioavailable inhibitor with potency in HWB comparable to celecoxib. Furthermore, 26 was selective for mPGES-1 inhibition versus other mechanisms in the prostanoid pathway. These factors led to the selection of 26 as a second clinical candidate. PMID:26653180

  3. Protein prenylation is required for aldosterone-stimulated Na+ transport.

    PubMed

    Blazer-Yost, B L; Hughes, C L; Nolan, P L

    1997-06-01

    Aldosterone stimulation of transcellular Na+ flux in polarized epithelial cells is dependent on at least one transmethylation reaction, but the substrate of this signaling step is unknown. Because it is clear that the majority of cellular protein methylation occurs in conjunction with protein prenylation, we examined the importance of prenylation to aldosterone-stimulated Na+ transport in the A6 cell line. Lovastatin, an inhibitor of the first committed step of the mevalonate pathway, inhibits the natriferic effect of aldosterone but does not inhibit insulin-stimulated Na+ flux. The addition of a farnesyl group does not appear to be involved in aldosterone's action. Neither alpha-hydroxyfarne-sylphosphonic acid, an inhibitor of farnesyl:protein transferase, nor N-acetyl-S-farnesyl-L-cysteine, an inhibitor of farnesylated protein methylation, inhibits the hormone-induced increase in Na+ transport. In contrast, N-acetyl-S-geranyl-geranyl-L-cysteine, an inhibitor of geranylgeranyl protein methylation, completely abolishes the aldosterone-induced increase in Na+ flux with no effect on insulin-mediated Na+ transport or cellular protein content. These data indicate that methylation of a geranylgeranylated protein is involved in aldosterone's natriferic action. PMID:9227422

  4. Aldosterone blockade in CKD: emphasis on pharmacology.

    PubMed

    Schwenk, Michael H; Hirsch, Jamie S; Bomback, Andrew S

    2015-03-01

    Besides its epithelial effect on sodium retention and potassium excretion in the distal tubule, aldosterone promotes inflammation and fibrosis in the heart, kidneys, and blood vessels. As glomerular filtration rate falls, aldosterone is inappropriately elevated relative to extracellular fluid expansion. In addition, studies in CKD patients on angiotensin-converting enzyme inhibitors, angiotensin receptor blockers, and/or direct renin inhibitors have shown that aldosterone levels paradoxically rise in approximately 30% to 40% of patients on these renin-angiotensin system-blocking drugs. Hence, there is interest in using mineralocorticoid receptor blockers that directly target the inflammatory and fibrotic effects of aldosterone in CKD patients. This interest, however, is tempered by a number of unresolved issues, including the safety of using such drugs in advanced CKD and ESRD populations, and the potential for differences in drug efficacy according to race and ethnicity of patient populations. A better understanding of mineralocorticoid receptor blocker pharmacology should help inform future research directions and clinical practice decisions as to how best to use these agents in CKD. PMID:25704349

  5. Intracellular mediators of potassium-induced aldosterone secretion

    SciTech Connect

    Ganguly, A.; Chiou, S.; Davis, J.S. )

    1990-01-01

    We have investigated the intracellular messengers of potassium in eliciting aldosterone secretion in calf adrenal glomerulosa cells since there were unresolved issues relating to the role of phosphoinositides, cAMP and protein kinases. We observed no evidence of hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP{sub 2}) in {sup 3}H-inositol labeled alf adrenal cells or increase of cAMP in response to potassium. Addition of calcium channel blocker, nitrendipine after stimulating adrenal glomerulosa cells with potassium, markedly inhibited aldosterone secretion. A calmodulin inhibitor (W-7) produced greater reduction of aldosterone secretion than an inhibitor of protein kinase C (H-7). These results suggest that a rise in cytosolic free calcium concentration through voltage-dependent calcium channel and calmodulin are the critical determinants of aldosterone secretion stimulated by potassium.

  6. Pharmacokinetics of TAK-475, a Squalene Synthase Inhibitor, in Rats and Dogs.

    PubMed

    Ebihara, T; Teshima, K; Kondo, T; Tagawa, Y; Moriwaki, T; Asahi, S

    2016-06-01

    The pharmacokinetics of TAK-475 (lapaquistat acetate), a squalene synthase inhibitor, was investigated in rats and dogs. After oral administration of (14)C-labeled TAK-475 ([(14)C]TAK-475) to rats and dogs at a dose of 10 mg/kg, the bioavailability (BA) was relatively low at 3.5 and 8.2%, respectively. The main component of the radioactivity in the plasma was M-I, which has a comparable pharmacological activity to TAK-475 in vitro. The radioactivity in the portal plasma after intraduodenal administration of [(14)C]TAK-475 to portal vein-cannulated rat was also mainly M-I, suggesting that most of the TAK-475 was hydrolyzed to M-I during the permeable process in the intestine. The concentrations of M-I in the liver, the main organ of cholesterol biosynthesis, were much higher than those in the plasma after oral administration of [(14)C]TAK-475 to rats. The main elimination route of the radioactivity was fecal excretion after oral administration of [(14)C]TAK-475 to rats and dogs, and the absorbed radioactivity was mainly excreted via the bile as M-I in rats. M-I excreted into the bile was partially subjected to enterohepatic circulation. These results suggest that although the BA values of TAK-475 are low, M-I can exert compensatory pharmacological effects in the animals. These pharmacokinetic characteristics in animals were also confirmed in the clinical studies. The evaluation of M-I disposition is important for the pharmacokinetics, pharmacodynamics and toxicity of TAK-475 in animals and humans. PMID:26839207

  7. Induction of intrachromosomal homologous recombination in human cells by raltitrexed, an inhibitor of thymidylate synthase.

    PubMed

    Waldman, Barbara Criscuolo; Wang, Yibin; Kilaru, Kasturi; Yang, Zhengguan; Bhasin, Alaukik; Wyatt, Michael D; Waldman, Alan S

    2008-10-01

    Thymidylate deprivation brings about "thymineless death" in prokaryotes and eukaryotes. Although the precise mechanism for thymineless death has remained elusive, inhibition of the enzyme thymidylate synthase (TS), which catalyzes the de novo synthesis of TMP, has served for many years as a basis for chemotherapeutic strategies. Numerous studies have identified a variety of cellular responses to thymidylate deprivation, including disruption of DNA replication and induction of DNA breaks. Since stalled or collapsed replication forks and strand breaks are generally viewed as being recombinogenic, it is not surprising that a link has been demonstrated between recombination induction and thymidylate deprivation in bacteria and lower eukaryotes. A similar connection between recombination and TS inhibition has been suggested by studies done in mammalian cells, but the relationship between recombination and TS inhibition in mammalian cells had not been demonstrated rigorously. To gain insight into the mechanism of thymineless death in mammalian cells, in this work we undertook a direct investigation of recombination in human cells treated with raltitrexed (RTX), a folate analog that is a specific inhibitor of TS. Using a model system to study intrachromosomal homologous recombination in cultured fibroblasts, we provide definitive evidence that treatment with RTX can stimulate accurate recombination events in human cells. Gene conversions not associated with crossovers were specifically enhanced several-fold by RTX. Additional experiments demonstrated that recombination events provoked by a double-strand break (DSB) were not impacted by treatment with RTX, nor was error-prone DSB repair via nonhomologous end-joining. Our work provides evidence that thymineless death in human cells is not mediated by corruption of DSB repair processes and suggests that an increase in chromosomal recombination may be an important element of cellular responses leading to thymineless death

  8. First Selective CYP11B1 Inhibitors for the Treatment of Cortisol-Dependent Diseases

    PubMed Central

    2010-01-01

    Outgoing from an etomidate-based design concept, we succeeded in the development of a series of highly active and selective inhibitors of CYP11B1, the key enzyme of cortisol biosynthesis, as potential drugs for the treatment of Cushing's syndrome and related diseases. Thus, compound 33 (IC50 = 152 nM) is the first CYP11B1 inhibitor showing a rather good selectivity toward the most important steroidogenic CYP enzymes aldosterone synthase (CYP11B2), the androgen-forming CYP17, and aromatase (estrogen synthase, CYP19). PMID:24900247

  9. Identification of natural inhibitors of Entamoeba histolytica cysteine synthase from microbial secondary metabolites

    PubMed Central

    Mori, Mihoko; Jeelani, Ghulam; Masuda, Yui; Sakai, Kazunari; Tsukui, Kumiko; Waluyo, Danang; Tarwadi; Watanabe, Yoshio; Nonaka, Kenichi; Matsumoto, Atsuko; Ōmura, Satoshi; Nozaki, Tomoyoshi; Shiomi, Kazuro

    2015-01-01

    Amebiasis is a common worldwide diarrheal disease, caused by the protozoan parasite, Entamoeba histolytica. Metronidazole has been a drug of choice against amebiasis for decades despite its known side effects and low efficacy against asymptomatic cyst carriers. E. histolytica is also capable of surviving sub-therapeutic levels of metronidazole in vitro. Novel drugs with different mode of action are therefore urgently needed. The sulfur assimilatory de novo L-cysteine biosynthetic pathway is essential for various cellular activities, including the proliferation and anti-oxidative defense of E. histolytica. Since the pathway, consisting of two reactions catalyzed by serine acetyltransferase (SAT) and cysteine synthase (CS, O-acetylserine sulfhydrylase), does not exist in humans, it is a rational drug target against amebiasis. To discover inhibitors against the CS of E. histolytica (EhCS), the compounds of Kitasato Natural Products Library were screened against two recombinant CS isozymes: EhCS1 and EhCS3. Nine compounds inhibited EhCS1 and EhCS3 with IC50 values of 0.31–490 μM. Of those, seven compounds share a naphthoquinone moiety, indicating the structural importance of the moiety for binding to the active site of EhCS1 and EhCS3. We further screened >9,000 microbial broths for CS inhibition and purified two compounds, xanthofulvin and exophillic acid from fungal broths. Xanthofulvin inhibited EhCS1 and EhCS3. Exophillic acid showed high selectivity against EhCS1, but exhibited no inhibition against EhCS3. In vitro anti-amebic activity of the 11 EhCS inhibitors was also examined. Deacetylkinamycin C and nanaomycin A showed more potent amebicidal activity with IC50 values of 18 and 0.8 μM, respectively, in the cysteine deprived conditions. The differential sensitivity of trophozoites against deacetylkinamycin C in the presence or absence of L-cysteine in the medium and the IC50 values against EhCS suggest the amebicidal effect of deacetylkinamycin C is due to

  10. Synthesis and biological evaluation of novel phosphoramidate derivatives of coumarin as chitin synthase inhibitors and antifungal agents.

    PubMed

    Ji, Qinggang; Ge, Zhiqiang; Ge, Zhixing; Chen, Kaizhi; Wu, Hualong; Liu, Xiaofei; Huang, Yanrong; Yuan, Lvjiang; Yang, Xiaolan; Liao, Fei

    2016-01-27

    A series of novel phosphoramidate derivatives of coumarin have been designed and synthesized as chitin synthase (CHS) inhibitors. All the synthesized compounds have been screened for their chitin synthase inhibition activity and antimicrobial activity in vitro. The bioactive assay manifested that most of the target compounds exhibited good efficacy against CHS and a variety of clinically important fungal pathogens. In particular, compound 7t with IC50 of 0.08 mM against CHS displayed stronger efficiency than the reference Polyoxin B with IC50 of 0.16 mM. In addition, the apparent Ki values of compound 7t was 0.096 mM while the Km of Chitin synthase prepared from Candida tropicalis was 3.86 mM for UDP-N-acetylglucosamine, and the result of the Ki showed that the compounds was a non-competitive inhibitor of the CHS. As far as the antifungal activity is concerned, compounds 7o, 7r and 7t were highly active against Aspergillus flavus with MIC values in the range of 1 μg/mL to 2 μg/Ml while the results of antibacterial screening showed that these compounds have negligible actions to the tested bacteria. These results indicated that the design of these compounds as antifungal agents was rational. PMID:26647304

  11. Structure-guided Discovery of Phenyl diketo-acids as Potent Inhibitors of M. tuberculosis Malate Synthase

    PubMed Central

    Krieger, Inna V.; Freundlich, Joel S.; Gawandi, Vijay B.; Roberts, Justin P.; Gawandi, Vidyadhar B.; Sun, Qingan; Owen, Joshua L.; Fraile, Maria T.; Huss, Sofia I.; Lavandera, Jose-Luis; Ioerger, Thomas R.; Sacchettini, James C.

    2012-01-01

    Summary The glyoxylate shunt plays an important role in fatty-acid metabolism, and has been shown to be critical to survival of several pathogens involved in chronic infections. For Mycobacterium tuberculosis (Mtb), a strain with a defective glyoxylate shunt was previously shown to be unable to establish infection in a mouse model. We report the development of novel phenyl-diketo acid (PDKA) inhibitors of malate synthase (GlcB), one of two glyoxylate shunt enzymes, using structure-based methods. PDKA inhibitors were active against Mtb grown on acetate, and over-expression of GlcB ameliorated this inhibition. Crystal structures of complexes of GlcB with PDKA inhibitors were used to guide optimization of potency. A selected PDKA compound demonstrated efficacy in a mouse model of tuberculosis. The discovery of these PDKA derivatives provides chemical validation of GlcB as an attractive target for tuberculosis therapeutics. PMID:23261599

  12. Lipophilic Bisphosphonates as Dual Farnesyl/Geranylgeranyl Diphosphate Synthase Inhibitors: An X-ray and NMR Investigation

    SciTech Connect

    Zhang, Y.; Cao, R; Yin, F; Hudock, M; Guo, R; Song, Y; No, J; Bergan, K; Leon, A; et al,

    2009-01-01

    Considerable effort has focused on the development of selective protein farnesyl transferase (FTase) and protein geranylgeranyl transferase (GGTase) inhibitors as cancer chemotherapeutics. Here, we report a new strategy for anticancer therapeutic agents involving inhibition of farnesyl diphosphate synthase (FPPS) and geranylgeranyl diphosphate synthase (GGPPS), the two enzymes upstream of FTase and GGTase, by lipophilic bisphosphonates. Due to dual site targeting and decreased polarity, the compounds have activities far greater than do current bisphosphonate drugs in inhibiting tumor cell growth and invasiveness, both in vitro and in vivo. We explore how these compounds inhibit cell growth and how cell activity can be predicted based on enzyme inhibition data, and using X-ray diffraction, solid state NMR, and isothermal titration calorimetry, we show how these compounds bind to FPPS and/or GGPPS.

  13. A novel bisphosphonate inhibitor of squalene synthase combined with a statin or a nitrogenous bisphosphonate in vitro[S

    PubMed Central

    Wasko, Brian M.; Smits, Jacqueline P.; Shull, Larry W.; Wiemer, David F.; Hohl, Raymond J.

    2011-01-01

    Statins and nitrogenous bisphosphonates (NBP) inhibit 3-hydroxy-3-methylglutaryl-coenzyme-A reductase (HMGCR) and farnesyl diphosphate synthase (FDPS), respectively, leading to depletion of farnesyl diphosphate (FPP) and disruption of protein prenylation. Squalene synthase (SQS) utilizes FPP in the first committed step from the mevalonate pathway toward cholesterol biosynthesis. Herein, we have identified novel bisphosphonates as potent and specific inhibitors of SQS, including the tetrasodium salt of 9-biphenyl-4,8-dimethyl-nona-3,7-dienyl-1,1-bisphosphonic acid (compound 5). Compound 5 reduced cholesterol biosynthesis and lead to a substantial intracellular accumulation of FPP without reducing cell viability in HepG2 cells. At high concentrations, lovastatin and zoledronate impaired protein prenylation and decreased cell viability, which limits their potential use for cholesterol depletion. When combined with lovastatin, compound 5 prevented lovastatin-induced FPP depletion and impairment of protein farnesylation. Compound 5 in combination with the NBP zoledronate completely prevented zoledronate-induced impairment of both protein farnesylation and geranylgeranylation. Cotreatment of cells with compound 5 and either lovastatin or zoledronate was able to significantly prevent the reduction of cell viability caused by lovastatin or zoledronate alone. The combination of an SQS inhibitor with an HMGCR or FDPS inhibitor provides a rational approach for reducing cholesterol synthesis while preventing nonsterol isoprenoid depletion. PMID:21903868

  14. Mechanistic analysis of a synthetic inhibitor of the Pseudomonas aeruginosa LasI quorum-sensing signal synthase

    PubMed Central

    Lidor, O.; Al-Quntar, A.; Pesci, E. C.; Steinberg, D.

    2015-01-01

    Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen responsible for many human infections. LasI is an acyl-homoserine lactone synthase that produces a quorum-sensing (QS) signal that positively regulates numerous P. aeruginosa virulence determinants. The inhibition of the LasI protein is therefore an attractive drug target. In this study, a novel in silico to in vitro complementation was applied to screen thiazolidinedione-type compounds for their ability to inhibit biofilm formation at concentrations not affecting bacterial growth. The compound (z)-5-octylidenethiazolidine-2, 4-dione (TZD-C8) was a strong inhibitor of biofilm formation and chosen for further study. Structural exploration of in silico docking predicted that the compound had high affinity for the LasI activity pocket. The TZD-C8 compound was also predicted to create hydrogen bonds with residues Arg30 and Ile107. Site-directed mutagenesis (SDM) of these two sites demonstrated that TZD-C8 inhibition was abolished in the lasI double mutant PAO-R30D, I107S. In addition, in vitro swarming motility and quorum sensing signal production were affected by TZD-C 8, confirming this compound alters the cell to cell signalling circuitry. Overall, this novel inhibitor of P. aeruginosa quorum sensing shows great promise and validates our mechanistic approach to discovering inhibitors of LuxI-type acyl-homoserine lactone synthases. PMID:26593271

  15. Zaragozic acids D and D2: potent inhibitors of squalene synthase and of Ras farnesyl-protein transferase.

    PubMed

    Dufresne, C; Wilson, K E; Singh, S B; Zink, D L; Bergstrom, J D; Rew, D; Polishook, J D; Meinz, M; Huang, L; Silverman, K C

    1993-11-01

    Two new zaragozic acids, D and D2, have been isolated from the keratinophilic fungus Amauroascus niger. Zaragozic acids D [4] and D2 [5] are related to the previously described zaragozic acids A [1], B [2], and C [3] and are potent inhibitors of squalene synthase. Furthermore, all the zaragozic acids (A, B, C, D, and D2) are also active against farnesyl transferase. Zaragozic acids D and D2 inhibit farnesyl transferase with IC50 values of 100 nM, while zaragozic acids A and B are less potent. PMID:8289063

  16. Attenuation of human nasal airway responses to bradykinin and histamine by inhibitors of nitric oxide synthase.

    PubMed Central

    Dear, J. W.; Ghali, S.; Foreman, J. C.

    1996-01-01

    1. The effects of inhibitors of nitric oxide synthase and local anaesthetics were studied on changes in human nasal airway patency and albumin extravasation in response to bradykinin and histamine, in vivo. 2. Compared with the action of the vasoconstrictor, ephedrine, 2.5 mumol, NG-nitro-L-arginine methyl ester (L-NAME), 1 mumol alone, did not change the resting value of the minimal cross-sectional area (A min) of the human nasal airway. L-NAME, 0.1 to 10 mumol, produced a dose-related inhibition of the reduction in A min caused by bradykinin, 300 micrograms. NG-monomethyl-L-arginine (L-NMMA), 1 mumol, similarly reduced the effect of bradykinin, 300 micrograms, on A min, but NG-nitro-D-arginine methyl ester (D-NAME), had no effect. L-NAME, 0.1 to 10 mumol, or L-NMMA, 10 mumol, failed to inhibit the effect of histamine, 300 micrograms on A min. 3. The inhibition by L-NAME, 1 mumol of the action of bradykinin, 300 micrograms on A min was maximal between 15 and 30 min after pretreatment with L-NAME. 4. L-NAME, 1 and 10 mumol, inhibited the extravasation of albumin into the nasal cavity induced by bradykinin, 300 micrograms, and also by histamine, 300 micrograms. D-NAME, 1 and 10 mumol had no effect on the extravasation of albumin in response to bradykinin or histamine. 5. L-Arginine, 30 mumol, reversed the effect of L-NAME, 1 mumol, on the bradykinin- and histamine-induced albumin extravasation into the nasal airway. 6. Local anaesthesia of the nasal airway with lignocaine, 10 mg, or benzocaine, 10 mg, failed to inhibit the reduction in A min or the albumin extravasation induced by either bradykinin, 300 micrograms, and histamine, 300 micrograms. 7. We conclude that the extravasation of plasma albumin caused by bradykinin and by histamine involves the generation of nitric oxide. The nasal blockage induced by bradykinin involves nitric oxide generation but the nasal blockage induced by histamine does not. PMID:8818341

  17. Aldosterone Activates NF-κB in the Collecting Duct

    PubMed Central

    Leroy, Valérie; De Seigneux, Sophie; Agassiz, Victor; Hasler, Udo; Rafestin-Oblin, Marie-Edith; Vinciguerra, Manlio; Martin, Pierre-Yves; Féraille, Eric

    2009-01-01

    Besides its classical effects on salt homeostasis in renal epithelial cells, aldosterone promotes inflammation and fibrosis and modulates cell proliferation. The proinflammatory transcription factor NF-κB has been implicated in cell proliferation, apoptosis, and regulation of transepithelial sodium transport. The effect of aldosterone on the NF-κB pathway in principal cells of the cortical collecting duct, a major physiologic target of aldosterone, is unknown. Here, in both cultured cells and freshly isolated rat cortical collecting duct, aldosterone activated the canonical NF-κB signaling pathway, leading to increased expression of several NF-κB–targeted genes (IκBα, plasminogen activator inhibitor 1, monocyte chemoattractant protein 1, IL-1β, and IL-6). Small interfering RNA–mediated knockdown of the serum and glucocorticoid-inducible kinase SGK1, a gene induced early in the response to aldosterone, but not pharmacologic inhibition of extracellular signal–regulated kinase and p38 kinase, attenuated aldosterone-induced NF-κB activation. Pharmacologic antagonism or knockdown of the mineralocorticoid receptor prevented aldosterone-induced NF-κB activity. In addition, activation of the glucocorticoid receptor inhibited the transactivation of NF-κB by aldosterone. In agreement with these in vitro findings, spironolactone prevented NF-κB–induced transcriptional activation observed in cortical collecting ducts of salt-restricted rats. In summary, aldosterone activates the canonical NF-κB pathway in principal cells of the cortical collecting duct by activating the mineralocorticoid receptor and by inducing SGK1. PMID:18987305

  18. New applications for known drugs: Human glycogen synthase kinase 3 inhibitors as modulators of Aspergillus fumigatus growth.

    PubMed

    Sebastián, Víctor; Manoli, Maria-Tsampika; Pérez, Daniel I; Gil, Carmen; Mellado, Emilia; Martínez, Ana; Espeso, Eduardo A; Campillo, Nuria E

    2016-06-30

    Invasive aspergillosis (IA) is one of the most severe forms of fungi infection. IA disease is mainly due to Aspergillus fumigatus, an air-borne opportunistic pathogen. Mortality rate caused by IA is still very high (50-95%), because of difficulty in early diagnostics and reduced antifungal treatment options, thus new and efficient drugs are necessary. The aim of this work is, using Aspergillus nidulans as non-pathogen model, to develop efficient drugs to treat IA. The recent discovered role of glycogen synthase kinase-3 homologue, GskA, in A. fumigatus human infection and our previous experience on human GSK-3 inhibitors focus our attention on this kinase as a target for the development of antifungal drugs. With the aim to identify effective inhibitors of colonial growth of A. fumigatus we use A. nidulans as an accurate model for in vivo and in silico studies. Several well-known human GSK-3β inhibitors were tested for inhibition of A. nidulans colony growth. Computational tools as docking studies and binding site prediction was used to explain the different biological profile of the tested inhibitors. Three of the five tested hGSK3β inhibitors are able to reduce completely the colonial growth by covalent bind to the enzyme. Therefore these compounds may be useful in different applications to eradicate IA. PMID:27131621

  19. Sulfa and trimethoprim-like drugs - antimetabolites acting as carbonic anhydrase, dihydropteroate synthase and dihydrofolate reductase inhibitors.

    PubMed

    Capasso, Clemente; Supuran, Claudiu T

    2014-06-01

    Recent advances in microbial genomics, synthetic organic chemistry and X-ray crystallography provided opportunities to identify novel antibacterial targets for the development of new classes of antibiotics and to design more potent antimicrobial compounds derived from existing antibiotics in clinical use for decades. The antimetabolites, sulfa drugs and trimethoprim (TMP)-like agents, are inhibitors of three families of enzymes. One family belongs to the carbonic anhydrases, which catalyze a simple but physiologically relevant reaction in all life kingdoms, carbon dioxide hydration to bicarbonate and protons. The other two enzyme families are involved in the synthesis of tetrahydrofolate (THF), i.e. dihydropteroate synthase (DHPS) and dihydrofolate reductase. The antibacterial agents belonging to the THF and DHPS inhibitors were developed decades ago and present significant bacterial resistance problems. However, the molecular mechanisms of drug resistance both to sulfa drugs and TMP-like inhibitors were understood in detail only recently, when several X-ray crystal structures of such enzymes in complex with their inhibitors were reported. Here, we revue the state of the art in the field of antibacterials based on inhibitors of these three enzyme families. PMID:23627736

  20. Analogs of the antituberculous agent pyrazinamide are competitive inhibitors of NADPH binding to M. tuberculosis fatty acid synthase I.

    PubMed

    Sayahi, Halimah; Pugliese, Kaitlin M; Zimhony, Oren; Jacobs, William R; Shekhtman, Alexander; Welch, John T

    2012-11-01

    Analogs of pyrazinamide (=pyrazine-2-carboxamide; PZA), an essential component of short-course antituberculous chemotherapy, such as 5-chloropyrazinamide (5-Cl-PZA) act as competitive inhibitors of NADPH binding to purified mycobacterial fatty acid synthase I (FAS I) as shown by Saturation Transfer Difference (STD) NMR studies. In addition, pyrazinoic acid esters (POE) and 5-Cl-POE reversibly bind to FAS I with the relatively greater affinity of longer-chain esters for FAS I, clear from the STD amplification factors. The competitive binding of PZA and 5-Cl-PZA clearly illustrates that both agents bind FAS. In contrast to PZA, at low NADPH concentrations 5-Cl-PZA is a cooperative inhibitor of NADPH binding. PMID:23161636

  1. A human fatty acid synthase inhibitor binds β-ketoacyl reductase in the keto-substrate site.

    PubMed

    Hardwicke, Mary Ann; Rendina, Alan R; Williams, Shawn P; Moore, Michael L; Wang, Liping; Krueger, Julie A; Plant, Ramona N; Totoritis, Rachel D; Zhang, Guofeng; Briand, Jacques; Burkhart, William A; Brown, Kristin K; Parrish, Cynthia A

    2014-09-01

    Human fatty acid synthase (hFAS) is a complex, multifunctional enzyme that is solely responsible for the de novo synthesis of long chain fatty acids. hFAS is highly expressed in a number of cancers, with low expression observed in most normal tissues. Although normal tissues tend to obtain fatty acids from the diet, tumor tissues rely on de novo fatty acid synthesis, making hFAS an attractive metabolic target for the treatment of cancer. We describe here the identification of GSK2194069, a potent and specific inhibitor of the β-ketoacyl reductase (KR) activity of hFAS; the characterization of its enzymatic and cellular mechanism of action; and its inhibition of human tumor cell growth. We also present the design of a new protein construct suitable for crystallography, which resulted in what is to our knowledge the first co-crystal structure of the human KR domain and includes a bound inhibitor. PMID:25086508

  2. Beta-blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, nitrate-hydralazine, diuretics, aldosterone antagonist, ivabradine, devices and digoxin (BANDAID(2) ): an evidence-based mnemonic for the treatment of systolic heart failure.

    PubMed

    Chia, N; Fulcher, J; Keech, A

    2016-06-01

    Heart failure causes significant morbidity and mortality, with recognised underutilisation rates of guideline-based therapies. Our aim was to review current evidence for heart failure treatments and derive a mnemonic summarising best practice, which might assist physicians in patient care. Treatments were identified for review from multinational society guidelines and recent randomised trials, with a primary aim of examining their effects in systolic heart failure patients on mortality, hospitalisation rates and symptoms. Secondary aims were to consider other clinical benefits. MEDLINE and EMBASE were searched using a structured keyword strategy and the retrieved articles were evaluated methodically to produce an optimised reference list for each treatment. We devised the mnemonic BANDAID (2) , standing for beta-blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker, nitrate-hydralazine (or potentially neprilysin inhibitor), diuretics, aldosterone antagonist, ivabradine, devices (automatic implantable cardioverter defibrillator, cardiac resynchronisation therapy or both) and digoxin as a representation of treatments with strong evidence for their use in systolic heart failure. Treatment with omega-3 fatty acids, statins or anti-thrombotic therapies has limited benefits in a general heart failure population. Adoption of this mnemonic for current evidence-based treatments for heart failure may help improve prescribing rates and patient outcomes in this debilitating, high mortality condition. PMID:26109136

  3. Phosphorylation of inhibitor-2 and activation of MgATP-dependent protein phosphatase by rat skeletal muscle glycogen synthase kinase

    SciTech Connect

    Hegazy, M.G.; Reimann, E.M.; Thysseril, T.J.; Schlender, K.K.

    1986-05-01

    Rat skeletal muscle contains a glycogen synthase kinase (GSK-M) which is not stimulated by Ca/sup 2 +/ or cAMP. This kinase has an apparent Mr of 62,000 and uses ATP but not GTP as a phosphoryl donor. GSK-M phosphorylated glycogen synthase at sites 2 and 3. It phosphorylated ATP-citrate lyase and activated MgATP-dependent phosphatase in the presence of ATP but not GTP. As expected, the kinase also phosphorylated phosphatase inhibitor 2 (I-2). Phosphatase incorporation reached approximately 0.3 mol/mol of I-2. Phosphopeptide maps were obtained by digesting /sup 32/P-labeled I-2 with trypsin and separating the peptides by reversed phase HPLC. Two partially separated /sup 32/P-labeled peaks were obtained when I-2 was phosphorylated with either GSK-M or glycogen synthase kinase 3 (GSK-3) and these peptides were different from those obtained when I-2 was phosphorylated with the catalytic subunit of cAMP-dependent protein kinase (CSU) or casein kinase II (CK-II). When I-2 was phosphorylated with GSK-M or GSK-3 and cleaved by CNBr, a single radioactive peak was obtained. Phosphoamino acid analysis showed that I-2 was phosphorylated by GSK-M or GSK-3 predominately in Thr whereas CSU and CK-II phosphorylated I-2 exclusively in Ser. These results indicate that GSK-M is similar to GSK-3 and to ATP-citrate lyase kinase. However, it appears to differ in Mr from ATP-citrate lyase kinase and it differs from GSK-3 in that it phosphorylates glycogen synthase at site 2 and it does not use GTP as a phosphoryl donor.

  4. Arsenic toxicity induced endothelial dysfunction and dementia: Pharmacological interdiction by histone deacetylase and inducible nitric oxide synthase inhibitors

    SciTech Connect

    Sharma, Bhupesh Sharma, P.M.

    2013-11-15

    Arsenic toxicity has been reported to damage all the major organs including the brain and vasculature. Dementia including Alzheimer's disease (AD) and vascular dementia (VaD) are posing greater risk to the world population as it is now increasing at a faster rate. We have investigated the role of sodium butyrate, a selective histone deacetylase (HDAC) inhibitor and aminoguanidine, a selective inducible nitric oxide synthase (iNOS) inhibitor in pharmacological interdiction of arsenic toxicity induced vascular endothelial dysfunction and dementia in rats. Arsenic toxicity was done by administering arsenic drinking water to rats. Morris water-maze (MWM) test was used for assessment of learning and memory. Endothelial function was assessed using student physiograph. Oxidative stress (aortic superoxide anion, serum and brain thiobarbituric acid reactive species, brain glutathione) and nitric oxide levels (serum nitrite/nitrate) were also measured. Arsenic treated rats have shown impairment of endothelial function, learning and memory, reduction in serum nitrite/nitrate and brain GSH levels along with increase in serum and brain TBARS. Sodium butyrate as well as aminoguanidine significantly convalesce arsenic induced impairment of learning, memory, endothelial function, and alterations in various biochemical parameters. It may be concluded that arsenic induces endothelial dysfunction and dementia, whereas, sodium butyrate, a HDAC inhibitor as well as aminoguanidine, a selective iNOS inhibitor may be considered as potential agents for the management of arsenic induced endothelial dysfunction and dementia. - Highlights: • As has induced endothelial dysfunction (Edf) and vascular dementia (VaD). • As has increased oxidative stress, AChE activity and decreased serum NO. • Inhibitors of HDAC and iNOS have attenuated As induced Edf and VaD. • Both the inhibitors have attenuated As induced biochemical changes. • Inhibitor of HDAC and iNOS has shown good potential in

  5. L-NAME, a nitric oxide synthase inhibitor, as a potential countermeasure to post-suspension hypotension in rats

    NASA Technical Reports Server (NTRS)

    Bayorh, M. A.; Socci, R. R.; Watts, S.; Wang, M.; Eatman, D.; Emmett, N.; Thierry-Palmer, M.

    2001-01-01

    A large number of astronauts returning from spaceflight experience orthostatic hypotension. This hypotension may be due to overproduction of vasodilatory mediators, such as nitric oxide (NO) and prostaglandins. To evaluate the role of the NO synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) as a countermeasure against the post-suspension reduction in mean arterial pressure (MAP), we assessed the cardiovascular responses and vascular reactivity to 7-day 30 degrees tail-suspension and a subsequent 6 hr post-suspension period in conscious rats. After a pre-suspension reading, direct MAP and heart rate (HR) were measured daily and every 2 hrs post-suspension. The NO synthase inhibitor L-NAME (20 mg/kg, i.v.), or saline, were administered after the 7th day reading prior to release from suspension and at 2 and 4 hrs post-suspension. At 6 hrs post-suspension, vascular reactivity was assessed. While MAP did not change during the suspension period, it was reduced post-suspension. Heart rate was not significantly altered. L-NAME administration reversed the post-suspension reduction in MAP. In addition, the baroreflex sensitivity for heart rate was modified by L-NAME. Thus, the post-suspension reduction in MAP may be due to overproduction of NO and altered baroreflex activity.

  6. Protective effects of a squalene synthase inhibitor, lapaquistat acetate (TAK-475), on statin-induced myotoxicity in guinea pigs.

    PubMed

    Nishimoto, Tomoyuki; Ishikawa, Eiichiro; Anayama, Hisashi; Hamajyo, Hitomi; Nagai, Hirofumi; Hirakata, Masao; Tozawa, Ryuichi

    2007-08-15

    High-dose statin treatment has been recommended as a primary strategy for aggressive reduction of LDL cholesterol levels and protection against coronary artery disease. The effectiveness of high-dose statins may be limited by their potential for myotoxic side effects. There is currently little known about the molecular mechanisms of statin-induced myotoxicity. Previously we showed that T-91485, an active metabolite of the squalene synthase inhibitor lapaquistat acetate (lapaquistat: a previous name is TAK-475), attenuated statin-induced cytotoxicity in human skeletal muscle cells [Nishimoto, T., Tozawa, R., Amano, Y., Wada, T., Imura, Y., Sugiyama, Y., 2003a. Comparing myotoxic effects of squalene synthase inhibitor, T-91485, and 3-hydroxy-3-methylglutaryl coenzyme A. Biochem. Pharmacol. 66, 2133-2139]. In the current study, we investigated the effects of lapaquistat administration on statin-induced myotoxicity in vivo. Guinea pigs were treated with either high-dose cerivastatin (1 mg/kg) or cerivastatin together with lapaquistat (30 mg/kg) for 14 days. Treatment with cerivastatin alone decreased plasma cholesterol levels by 45% and increased creatine kinase (CK) levels by more than 10-fold (a marker of myotoxicity). The plasma CK levels positively correlated with the severity of skeletal muscle lesions as assessed by histopathology. Co-administration of lapaquistat almost completely prevented the cerivastatin-induced myotoxicity. Administration of mevalonolactone (100 mg/kg b.i.d.) prevented the cerivastatin-induced myotoxicity, confirming that this effect is directly related to HMG-CoA reductase inhibition. These results strongly suggest that cerivastatin-induced myotoxicity is due to depletion of mevalonate derived isoprenoids. In addition, squalene synthase inhibition could potentially be used clinically to prevent statin-induced myopathy. PMID:17599378

  7. Protective effects of a squalene synthase inhibitor, lapaquistat acetate (TAK-475), on statin-induced myotoxicity in guinea pigs

    SciTech Connect

    Nishimoto, Tomoyuki; Ishikawa, Eiichiro; Anayama, Hisashi; Hamajyo, Hitomi; Nagai, Hirofumi; Hirakata, Masao; Tozawa, Ryuichi

    2007-08-15

    High-dose statin treatment has been recommended as a primary strategy for aggressive reduction of LDL cholesterol levels and protection against coronary artery disease. The effectiveness of high-dose statins may be limited by their potential for myotoxic side effects. There is currently little known about the molecular mechanisms of statin-induced myotoxicity. Previously we showed that T-91485, an active metabolite of the squalene synthase inhibitor lapaquistat acetate (lapaquistat: a previous name is TAK-475), attenuated statin-induced cytotoxicity in human skeletal muscle cells [Nishimoto, T., Tozawa, R., Amano, Y., Wada, T., Imura, Y., Sugiyama, Y., 2003a. Comparing myotoxic effects of squalene synthase inhibitor, T-91485, and 3-hydroxy-3-methylglutaryl coenzyme A. Biochem. Pharmacol. 66, 2133-2139]. In the current study, we investigated the effects of lapaquistat administration on statin-induced myotoxicity in vivo. Guinea pigs were treated with either high-dose cerivastatin (1 mg/kg) or cerivastatin together with lapaquistat (30 mg/kg) for 14 days. Treatment with cerivastatin alone decreased plasma cholesterol levels by 45% and increased creatine kinase (CK) levels by more than 10-fold (a marker of myotoxicity). The plasma CK levels positively correlated with the severity of skeletal muscle lesions as assessed by histopathology. Co-administration of lapaquistat almost completely prevented the cerivastatin-induced myotoxicity. Administration of mevalonolactone (100 mg/kg b.i.d.) prevented the cerivastatin-induced myotoxicity, confirming that this effect is directly related to HMG-CoA reductase inhibition. These results strongly suggest that cerivastatin-induced myotoxicity is due to depletion of mevalonate derived isoprenoids. In addition, squalene synthase inhibition could potentially be used clinically to prevent statin-induced myopathy.

  8. Extraordinarily high aldosterone, 901.0 ng/dL, in a patient with primary aldosteronism: an insight into the underlying mechanism.

    PubMed

    Okubo, Yosuke; Sato, Yuka; Nakasone, Yasuto; Shirotori, Katsuko; Oguchi, Kazuhiro; Matsushita, Tsuyoshi; Nishikawa, Tetsuo; Yamazaki, Yuto; Sasano, Hironobu; Komatsu, Mitsuhisa; Yamauchi, Keishi; Aizawa, Toru

    2016-02-29

    A 43-yr-old hypertensive male was admitted due to hypokalemia (1.8 mEq/L) and renal dysfunction (eGFR, 20.0 mL/min/1.73 m(2)). His plasma aldosterone was 901.0 ng/dL, plasma renin activity 5.7 ng/mL/hr, and aldosterone/renin activity ratio 158. Angiotensin II (AII) was 0.7 pg/mL, ACTH <1.0 pg/mL, and cortisol 21.6 μg/dL. Liquid chromatography-tandem mass spectrometry analysis showed that aldosterone (104 times the control) as well as its precursors were significantly elevated in the patient's plasma. A left adrenal (4-cm-diameter) tumor with (131)I-Adosterol® uptake was found and removed. Four days later, plasma aldosterone and renin activity had dropped to 7.73 ng/dL and 1.6 ng/mL/hr, respectively. However, they rose to 24.0 ng/dL and 10.9 ng/mL/hr, respectively, by Day 102. Nevertheless, magnetic resonance angiography found no evidence of a renovascular lesion. The tumor was a benign adrenocortical adenoma composed predominantly of clear cells positive for 17α-hydroxylase, [hydroxy-delta-5-steroid dehydrogenase, 3 beta- and steroid delta-isomerases], and aldosterone synthase. A quantitative real-time polymerase chain reaction analysis of the tumor cells revealed that expression of the gene encoding aldosterone synthase was 85 times the control level. In addition, the tumor cells harbored G151R mutation of the inward rectifying potassium channel subfamily j, member 5 gene. The striking overexpression of aldosterone synthase by the tumor cells was considered the primary mechanism for the extravagant overproduction of aldosterone in this case. This overexpression may have resulted from integration of signals from AII and forced membrane depolarization due to the potassium channel mutation. PMID:26549209

  9. Stereocontrolled Synthesis of a Potential Transition-State Inhibitor of the Salicylate Synthase MbtI from Mycobacterium tuberculosis

    PubMed Central

    Liu, Zheng; Liu, Feng; Aldrich, Courtney C.

    2015-01-01

    Mycobactins are small-molecule iron chelators (siderophores) produced by Mycobacterium tuberculosis (Mtb) for iron mobilization. The bifunctional salicylate synthase MbtI catalyzes the first step of mycobactin biosynthesis through the conversion of the primary metabolite chorismate into salicylic acid via isochorismate. We report the design, synthesis and biochemical evaluation of an inhibitor based on the putative transition-state (TS) for the isochorismatase partial reaction of MbtI. The inhibitor mimics the hypothesized charge build-up at C-4 of chorismate in the TS as well as C-O bond-formation at C-6. Another important design element of the inhibitor is replacement of the labile pyruvate side-chain in chorismate with a stable C-linked propionate isostere. We developed a stereocontrolled synthesis of the highly functionalized cyclohexene inhibitor that features an asymmetric aldol reaction using a titanium enolate, diastereoselective Grignard addition to a tert-butanesulfinyl aldimine, and ring closing olefin metathesis as key steps. PMID:26035083

  10. Novel 2,4-Disubstituted Pyrimidines as Potent, Selective, and Cell-Permeable Inhibitors of Neuronal Nitric Oxide Synthase

    PubMed Central

    2014-01-01

    Selective inhibition of neuronal nitric oxide synthase (nNOS) is an important therapeutic approach to target neurodegenerative disorders. However, the majority of the nNOS inhibitors developed are arginine mimetics and, therefore, suffer from poor bioavailability. We designed a novel strategy to combine a more pharmacokinetically favorable 2-imidazolylpyrimidine head with promising structural components from previous inhibitors. In conjunction with extensive structure–activity studies, several highly potent and selective inhibitors of nNOS were discovered. X-ray crystallographic analysis reveals that these type II inhibitors utilize the same hydrophobic pocket to gain strong inhibitory potency (13), as well as high isoform selectivity. Interestingly, select compounds from this series (9) showed good permeability and low efflux in a Caco-2 assay, suggesting potential oral bioavailability, and exhibited minimal off-target binding to 50 central nervous system receptors. Furthermore, even with heme-coordinating groups in the molecule, modifying other pharmacophoric fragments minimized undesirable inhibition of cytochrome P450s from human liver microsomes. PMID:25489882

  11. Efficacy of small-molecule glycogen synthase kinase-3 inhibitors in the postnatal rat model of tau hyperphosphorylation

    PubMed Central

    Selenica, M-L; Jensen, H S; Larsen, A K; Pedersen, M L; Helboe, L; Leist, M; Lotharius, J

    2007-01-01

    Background and purpose: Glycogen synthase kinase-3 (GSK-3) affects neuropathological events associated with Alzheimeŕs disease (AD) such as hyperphosphorylation of the protein, tau. GSK-3β expression, enzyme activity and tau phosphorylated at AD-relevant epitopes are elevated in juvenile rodent brains. Here, we assess five GSK-3β inhibitors and lithium in lowering phosphorylated tau (p-tau) and GSK-3β enzyme activity levels in 12-day old postnatal rats. Experimental approach: Brain levels of inhibitors following treatment in vivo were optimized based on pharmacokinetic data. At optimal doses, p-tau (Ser396) levels in brain tissue was measured by immunoblotting and correlated with GSK-3β enzyme activities in the same tissues. Effects of GSK inhibitors on p-tau, GSK-3β activities and cell death were measured in a human neuronal cell line (LUHMES). Key results: Lithium and CHIR98014 reduced tau phosphorylation (Ser396) in the cortex and hippocampus of postnatal rats, while Alsterpaullone and SB216763 were effective only in hippocampus. AR-A014418 and Indirubin-3′-monoxime were ineffective in either brain region. Inhibition of p-tau in brain required several-fold higher levels of GSK inhibitors than the IC50 values obtained in recombinant or cell-based GSK-3β enzyme activity assays. The inhibitory effect on GSK-3β activity ex vivo correlated with protection against cell death and decrease of p-tau- in LUHMES cells, using low μM inhibitor concentrations. Conclusions and Implications: Selective small-molecule inhibitors of GSK-3 reduce tau phosphorylation in vivo. These findings corroborate earlier suggestions that GSK-3β may be an attractive target for disease-modification in AD and related conditions where tau phosphorylation is believed to contribute to disease pathogenesis. PMID:17906685

  12. Three-dimensional structures of Plasmodium falciparum spermidine synthase with bound inhibitors suggest new strategies for drug design

    SciTech Connect

    Sprenger, Janina; Svensson, Bo; Hålander, Jenny; Carey, Jannette; Persson, Lo; Al-Karadaghi, Salam

    2015-03-01

    In this work, X-ray crystallography was used to examine ligand complexes of spermidine synthase from the malaria parasite Plasmodium falciparum (PfSpdS). The enzymes of the polyamine-biosynthesis pathway have been proposed to be promising drug targets in the treatment of malaria. Spermidine synthase (SpdS; putrescine aminopropyltransferase) catalyzes the transfer of the aminopropyl moiety from decarboxylated S-adenosylmethionine to putrescine, leading to the formation of spermidine and 5′-methylthioadenosine (MTA). In this work, X-ray crystallography was used to examine ligand complexes of SpdS from the malaria parasite Plasmodium falciparum (PfSpdS). Five crystal structures were determined of PfSpdS in complex with MTA and the substrate putrescine, with MTA and spermidine, which was obtained as a result of the enzymatic reaction taking place within the crystals, with dcAdoMet and the inhibitor 4-methylaniline, with MTA and 4-aminomethylaniline, and with a compound predicted in earlier in silico screening to bind to the active site of the enzyme, benzimidazol-(2-yl)pentan-1-amine (BIPA). In contrast to the other inhibitors tested, the complex with BIPA was obtained without any ligand bound to the dcAdoMet-binding site of the enzyme. The complexes with the aniline compounds and BIPA revealed a new mode of ligand binding to PfSpdS. The observed binding mode of the ligands, and the interplay between the two substrate-binding sites and the flexible gatekeeper loop, can be used in the design of new approaches in the search for new inhibitors of SpdS.

  13. Adipocyte Mineralocorticoid Receptor Activation Leads to Metabolic Syndrome and Induction of Prostaglandin D2 Synthase.

    PubMed

    Urbanet, Riccardo; Nguyen Dinh Cat, Aurelie; Feraco, Alessandra; Venteclef, Nicolas; El Mogrhabi, Soumaya; Sierra-Ramos, Catalina; Alvarez de la Rosa, Diego; Adler, Gail K; Quilliot, Didier; Rossignol, Patrick; Fallo, Francesco; Touyz, Rhian M; Jaisser, Frédéric

    2015-07-01

    Metabolic syndrome is a major risk factor for the development of diabetes mellitus and cardiovascular diseases. Pharmacological antagonism of the mineralocorticoid receptor (MR), a ligand-activated transcription factor, limits metabolic syndrome in preclinical models, but mechanistic studies are lacking to delineate the role of MR activation in adipose tissue. In this study, we report that MR expression is increased in visceral adipose tissue in a preclinical mouse model of metabolic syndrome and in obese patients. In vivo conditional upregulation of MR in mouse adipocytes led to increased weight and fat mass, insulin resistance, and metabolic syndrome features without affecting blood pressure. We identified prostaglandin D2 synthase as a novel MR target gene in adipocytes and AT56, a specific inhibitor of prostaglandin D2 synthase enzymatic activity, blunted adipogenic aldosterone effects. Moreover, translational studies showed that expression of MR and prostaglandin D2 synthase is strongly correlated in adipose tissues from obese patients. PMID:25966493

  14. Rapid Induction of Aldosterone Synthesis in Cultured Neonatal Rat Cardiomyocytes under High Glucose Conditions

    PubMed Central

    Nagoshi, Tomohisa; Nishikawa, Tetsuo; Date, Taro; Yoshimura, Michihiro

    2013-01-01

    In addition to classical adrenal cortical biosynthetic pathway, there is increasing evidence that aldosterone is produced in extra-adrenal tissues. Although we previously reported aldosterone production in the heart, the concept of cardiac aldosterone synthesis remains controversial. This is partly due to lack of established experimental models representing aldosterone synthase (CYP11B2) expression in robustly reproducible fashion. We herein investigated suitable conditions in neonatal rat cardiomyocytes (NRCMs) culture system producing CYP11B2 with considerable efficacy. NRCMs were cultured with various glucose doses for 2–24 hours. CYP11B2 mRNA expression and aldosterone concentrations secreted from NRCMs were determined using real-time PCR and enzyme immunoassay, respectively. We found that suitable conditions for CYP11B2 induction included four-hour incubation with high glucose conditions. Under these particular conditions, CYP11B2 expression, in accordance with aldosterone secretion, was significantly increased compared to those observed in the cells cultured under standard-glucose condition. Angiotensin II receptor blocker partially inhibited this CYP11B2 induction, suggesting that there is local renin-angiotensin-aldosterone system activation under high glucose conditions. The suitable conditions for CYP11B2 induction in NRCMs culture system are now clarified: high-glucose conditions with relatively brief period of culture promote CYP11B2 expression in cardiomyocytes. The current system will help to accelerate further progress in research on cardiac tissue aldosterone synthesis. PMID:24288663

  15. Nitric oxide synthase inhibitors can antagonize neurogenic and calcitonin gene-related peptide induced dilation of dural meningeal vessels

    PubMed Central

    Akerman, S; Williamson, D J; Kaube, H; Goadsby, P J

    2002-01-01

    The detailed pathophysiology of migraine is beginning to be understood and is likely to involve activation of trigeminovascular afferents. Clinically effective anti-migraine compounds are believed to have actions that include peripheral inhibition of calcitonin gene-related peptide (CGRP) release from trigeminal neurones, or preventing dural vessel dilation, or both. CGRP antagonists can block both neurogenic and CGRP-induced dural vessel dilation. Nitric oxide (NO) can induce headache in migraine patients and often triggers a delayed migraine. The initial headache is thought to be caused via a direct action of the NO–cGMP pathway that causes vasodilation by vascular smooth muscle relaxation, while the delayed headache is likely to be a result of triggering trigeminovascular activation. Nitric oxide synthase (NOS) inhibitors are effective in the treatment of acute migraine. The present studies used intravital microscopy to examine the effects of specific NOS inhibitors on neurogenic dural vasodilation (NDV) and CGRP-induced dilation. The non-specific and neuronal NOS (nNOS) inhibitors were able to partially inhibit NDV, while the non-specific and endothelial NOS (eNOS) inhibitors were able to partially inhibit the CGRP induced dilation. There was no effect of the inducible NOS (iNOS) inhibitor. The data suggest that the delayed headache response triggered by NO donors in humans may be due, in part, to increased nNOS activity in the trigeminal system that causes CGRP release and dural vessel dilation. Further, eNOS activity in the endothelium causes NO production and smooth muscle relaxation by direct activation of the NO–cGMP pathway, and may be involved in the initial headache response. PMID:12183331

  16. Iminosugar-based inhibitors of glucosylceramide synthase increase brain glycosphingolipids and survival in a mouse model of Sandhoff disease.

    PubMed

    Ashe, Karen M; Bangari, Dinesh; Li, Lingyun; Cabrera-Salazar, Mario A; Bercury, Scott D; Nietupski, Jennifer B; Cooper, Christopher G F; Aerts, Johannes M F G; Lee, Edward R; Copeland, Diane P; Cheng, Seng H; Scheule, Ronald K; Marshall, John

    2011-01-01

    The neuropathic glycosphingolipidoses are a subgroup of lysosomal storage disorders for which there are no effective therapies. A potential approach is substrate reduction therapy using inhibitors of glucosylceramide synthase (GCS) to decrease the synthesis of glucosylceramide and related glycosphingolipids that accumulate in the lysosomes. Genz-529468, a blood-brain barrier-permeant iminosugar-based GCS inhibitor, was used to evaluate this concept in a mouse model of Sandhoff disease, which accumulates the glycosphingolipid GM2 in the visceral organs and CNS. As expected, oral administration of the drug inhibited hepatic GM2 accumulation. Paradoxically, in the brain, treatment resulted in a slight increase in GM2 levels and a 20-fold increase in glucosylceramide levels. The increase in brain glucosylceramide levels might be due to concurrent inhibition of the non-lysosomal glucosylceramidase, Gba2. Similar results were observed with NB-DNJ, another iminosugar-based GCS inhibitor. Despite these unanticipated increases in glycosphingolipids in the CNS, treatment nevertheless delayed the loss of motor function and coordination and extended the lifespan of the Sandhoff mice. These results suggest that the CNS benefits observed in the Sandhoff mice might not necessarily be due to substrate reduction therapy but rather to off-target effects. PMID:21738789

  17. Iminosugar-Based Inhibitors of Glucosylceramide Synthase Increase Brain Glycosphingolipids and Survival in a Mouse Model of Sandhoff Disease

    PubMed Central

    Ashe, Karen M.; Bangari, Dinesh; Li, Lingyun; Cabrera-Salazar, Mario A.; Bercury, Scott D.; Nietupski, Jennifer B.; Cooper, Christopher G. F.; Aerts, Johannes M. F. G.; Lee, Edward R.; Copeland, Diane P.; Cheng, Seng H.; Scheule, Ronald K.; Marshall, John

    2011-01-01

    The neuropathic glycosphingolipidoses are a subgroup of lysosomal storage disorders for which there are no effective therapies. A potential approach is substrate reduction therapy using inhibitors of glucosylceramide synthase (GCS) to decrease the synthesis of glucosylceramide and related glycosphingolipids that accumulate in the lysosomes. Genz-529468, a blood-brain barrier-permeant iminosugar-based GCS inhibitor, was used to evaluate this concept in a mouse model of Sandhoff disease, which accumulates the glycosphingolipid GM2 in the visceral organs and CNS. As expected, oral administration of the drug inhibited hepatic GM2 accumulation. Paradoxically, in the brain, treatment resulted in a slight increase in GM2 levels and a 20-fold increase in glucosylceramide levels. The increase in brain glucosylceramide levels might be due to concurrent inhibition of the non-lysosomal glucosylceramidase, Gba2. Similar results were observed with NB-DNJ, another iminosugar-based GCS inhibitor. Despite these unanticipated increases in glycosphingolipids in the CNS, treatment nevertheless delayed the loss of motor function and coordination and extended the lifespan of the Sandhoff mice. These results suggest that the CNS benefits observed in the Sandhoff mice might not necessarily be due to substrate reduction therapy but rather to off-target effects. PMID:21738789

  18. Up-regulation of FGF23 release by aldosterone.

    PubMed

    Zhang, Bingbing; Umbach, Anja T; Chen, Hong; Yan, Jing; Fakhri, Hajar; Fajol, Abul; Salker, Madhuri S; Spichtig, Daniela; Daryadel, Arezoo; Wagner, Carsten A; Föller, Michael; Lang, Florian

    2016-02-01

    The fibroblast growth factor (FGF23) plasma level is high in cardiac and renal failure and is associated with poor clinical prognosis of these disorders. Both diseases are paralleled by hyperaldosteronism. Excessive FGF23 levels and hyperaldosteronism are further observed in Klotho-deficient mice. The present study explored a putative aldosterone sensitivity of Fgf23 transcription and secretion the putative involvement of the aldosterone sensitive serum & glucocorticoid inducible kinase SGK1, SGK1 sensitive transcription factor NFκB and store operated Ca(2+) entry (SOCE). Serum FGF23 levels were determined by ELISA in mice following sham treatment or exposure to deoxycorticosterone acetate (DOCA) or salt depletion. In osteoblastic UMR106 cells transcript levels were quantified by qRT-PCR, cytosolic Ca(2+) concentration utilizing Fura-2-fluorescence, and SOCE from Ca(2+) entry following store depletion by thapsigargin. As a result, DOCA treatment and salt depletion of mice elevated the serum C-terminal FGF23 concentration. In UMR106 cells aldosterone enhanced and spironolactone decreased SOCE. Aldosterone further increased Fgf23 transcript levels in UMR106 cells, an effect reversed by mineralocorticoid receptor blockers spironolactone and eplerenone, SGK1 inhibitor EMD638683, NFκB-inhibitor withaferin A, and Ca(2+) channel blocker YM58483. In conclusion, Fgf23 expression is up-regulated by aldosterone, an effect sensitive to SGK1, NFκB and store-operated Ca(2+) entry. PMID:26773502

  19. Massive production of farnesol-derived dicarboxylic acids in mice treated with the squalene synthase inhibitor zaragozic acid A.

    PubMed

    Vaidya, S; Bostedor, R; Kurtz, M M; Bergstrom, J D; Bansal, V S

    1998-07-01

    The zaragozic acids are potent inhibitors of squalene synthase. In vivo studies in mice confirmed our earlier observations that inhibition of squalene synthase by zaragozic acid A was accompanied by an increase in the incorporation of label from [3H]mevalonate into farnesyl-diphosphate (FPP)-derived isoprenoic acids (J. D. Bergstrom et al., 1993, Proc. Natl. Acad. Sci. USA 90, 80-84). Farnesyl-diphosphate-derived metabolites appear transiently in the liver. We were unable to detect any farnesol formation in the zaragozic acid-treated animals which indicates that FPP is readily converted to farnesoic acid and dicarboxylic acids in the liver. These metabolites were found to be produced only in the liver and not in the kidney. trans-3,7-Dimethyl-2-octaen-1,8-dioic acid and 3, 7-dimethyloctan-1,8-dioic acid were identified as the major end products of farnesyl-diphosphate metabolism in the urine of mice treated with zaragozic acid A. Quantitative analysis of these FPP-derived dicarboxylic acids by gas-liquid chromatography revealed that approximately 11 mg of total dicarboxylic acids is excreted per day into the urine of a mouse after 3 days of treatment with zaragozic acid A. PMID:9647670

  20. Biological activities of novel zaragozic acids, the potent inhibitors of squalene synthase, produced by the fungus, Mollisia sp. SANK 10294.

    PubMed

    Tanimoto, T; Hamano, K; Onodera, K; Hosoya, T; Kakusaka, M; Hirayama, T; Shimada, Y; Koga, T; Tsujita, Y

    1997-05-01

    Four novel zaragozic acids, F-10863A, B, C and D, were isolated from a culture broth of the fungus Mollisia sp. SANK 10294. F-10863 compounds contain a 4,6,7-trihydroxy-2,8-dioxyobicyclo-[3.2.1]octane-3,4,5-tricarboxyl ic acid core like previously reported zaragozic acids, but the structures of the side chains are different. Recently, it was found that F-10863A is identical to zaragozic acid D3, while the other three are novel compounds. F-10863 compounds are potent inhibitors of squalene synthase like previously reported zaragozic acids, and, furthermore, they exhibit serum cholesterol-lowering activity in vivo. PMID:9207908

  1. Inhibitors of the Salicylate Synthase (MbtI) from Mycobacterium tuberculosis Discovered by High-Throughput Screening

    PubMed Central

    Vasan, Mahalakshmi; Neres, João; Williams, Jessica; Wilson, Daniel J.; Teitelbaum, Aaron M.; Remmel, Rory P.; Aldrich, Courtney C.

    2010-01-01

    A simple steady-state kinetic high-throughput assay was developed for the salicylate synthase MbtI from Mycobacterium tuberculosis, which catalyzes the first committed step of mycobactin biosynthesis. The mycobactins are small-molecule iron chelators produced by M. tuberculosis, and their biosynthesis has been identified as a promising target for the development of new antitubercular agents. The assay was miniaturized to a 384-well plate format and high-throughput screening was performed at the National Screening Laboratory for the Regional Centers of Excellence in Biodefense and Emerging Infectious Diseases (NSRB). Three classes of compounds were identified comprising the benzisothiazolones (class I), diarylsulfones (class II), and benzimidazole-2-thiones (class III). Each of these compound series was further pursued to investigate their biochemical mechanism and structure–activity relationships. Benzimidazole-2-thione 4 emerged as the most promising inhibitor owing to its potent reversible inhibition. PMID:21053346

  2. Synthesis of benzimidazole based thiadiazole and carbohydrazide conjugates as glycogen synthase kinase-3β inhibitors with anti-depressant activity.

    PubMed

    Khan, Imran; Tantray, Mushtaq A; Hamid, Hinna; Alam, Mohammad Sarwar; Kalam, Abul; Dhulap, Abhijeet

    2016-08-15

    A series of benzimidazole based thiadiazole and carbohydrazide conjugates have been synthesized and evaluated for inhibition of glycogen synthase kinase-3β and anti-depressant effect. Compounds 4f, 4j, 5b, 5g and 5i were found to be the most potent inhibitors of GSK-3β in vitro amongst the twenty-five benzimidazole based thiadiazole and carbohydrazide conjugates synthesized. Compound 5i was also found to exhibit significant antidepressant activity in vivo at 50mg/kg, when compared to fluoxetine, a known antidepressant drug. The molecular docking studies revealed multiple hydrogen bond interactions by the synthesized compounds with various amino acid residues, viz, ASP-133, LYS-183, PRO-136, VAL-135, TYR-134, or LYS-60 at the GSK-3β receptor site. PMID:27406796

  3. SFE/SFHTA/AFCE consensus on primary aldosteronism, part 5: Genetic diagnosis of primary aldosteronism.

    PubMed

    Zennaro, Maria-Christina; Jeunemaitre, Xavier

    2016-07-01

    While the majority of cases of primary aldosteronism (PA) are sporadic, four forms of autosomal-dominant inheritance have been described: familial hyperaldosteronism (FH) types I to IV. FH-I, also called glucocorticoid-remediable aldosteronism, is characterized by early and severe hypertension, usually before the age of 20 years. It is due to the formation of a chimeric gene between the adjacent CYP11B2 and CYP11B1 genes (coding for aldosterone synthase and 11β-hydroxylase, respectively). FH-I is often associated with family history of stroke before 40years of age. FH-II is clinically and biochemically indistinguishable from sporadic forms of PA and is only diagnosed on the basis of two or more affected family members. No causal genes have been identified so far and no genetic test is available. FH-III is characterized by severe and early-onset hypertension in children and young adults, resistant to treatment and associated with severe hypokalemia. Mild forms, resembling FH-II, have been described. FH-III is due to gain-of-function mutations in the KCNJ5 gene. Recently, a new autosomal-dominant form of familial PA, FH-IV, associated with mutations in the CACNA1H gene, was described in patients with hypertension and PA before the age of 10years. In rare cases, PA may be associated with complex neurologic disorder involving epileptic seizures and cerebral palsy (Primary Aldosteronism, Seizures, and Neurologic Abnormalities [PASNA]) due to de novo germline CACNA1D mutations. PMID:27315758

  4. Neuronal nitric oxide synthase inhibitor, 7-nitroindazole, delays motor dysfunction and spinal motoneuron degeneration in the wobbler mouse.

    PubMed

    Ikeda, K; Iwasaki, Y; Kinoshita, M

    1998-09-18

    Gene mutations of superoxide dismutase (SOD) have been discovered in familial amyotrophic lateral sclerosis (ALS). Neuronal nitric oxide synthase (NOS), endothelial NOS and 3-nitrotyrosine immunoreactivities are selectively increased in the spinal motoneurons of sporadic ALS. Other study suggests that 3-nitrotyrosine immunoreactivity is enhanced in the spinal motoneurons of sporadic and familial ALS patients. The hypothesis is postulated that increased production of radical species, such as superoxide and peroxynitrite, may cause motoneuron degeneration in ALS. There are increased amounts of nitric oxide and SOD hypoactivities in the brain and spinal cord of wobbler mice. NOS is also induced in the vacuolated spinal motoneurons or axons in this animal. Free radicals might contribute to the pathogenesis of wobbler mouse motoneuron disease. Lecithinized SOD treatment has retarded the progression of this disease. This evidence allowed us to determine whether NOS inhibitors delay progression of wobbler mouse motoneuron disease. After clinical diagnosis at age 3-4 weeks, wobbler mice were injected with intraperitoneal non-selective NOS inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME, 50 mg/kg), two doses of neuronal NOS inhibitor, 7-nitroindazole (5 or 50 mg/kg) or a vehicle solution, daily for 4 weeks in a blind fashion. In comparison with vehicle, 7-nitroindazole-treated mice potentiated grip strength and attenuated deformities in the forelimbs. 7-Nitroindazole treatment increased the biceps muscle weight, reduced denervation muscle atrophy, and suppressed degeneration of spinal motoneurons. To a lesser degree, L-NAME-treated mice displayed slowed progression of disease. The present studies indicate that neuronal NOS inhibitor may be a candidate for promising therapy in lower motoneuron disease or motor neuropathy. PMID:9804111

  5. Mechanism of action of anticandidal dipeptides containing inhibitors of glucosamine-6-phosphate synthase.

    PubMed Central

    Milewski, S; Andruszkiewicz, R; Kasprzak, L; Mazerski, J; Mignini, F; Borowski, E

    1991-01-01

    The mechanism of anticandidal action of novel synthetic dipeptides containing N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP) residues was shown to be consistent with the "warhead delivery" concept. FMDP dipeptides were shown to be transported into Candida albicans cells by the di-tripeptide permease and subsequently hydrolyzed by intracellular peptidases, especially aminopeptidase. The anticandidal activity of the particular FMDP dipeptide was influenced by the rate of its transport and, to a lower extent, by the intracellular cleavage rate. A high transport rate accompanied by a high cleavage rate resulted in the high anticandidal activity of L-norvalyl-FMDP. The strong growth-inhibitory effect of this compound was the consequence of inhibition of the enzyme glucosamine-6-phosphate synthase by the released FMDP. The action of L-norvalyl-FMDP on exponentially growing C. albicans cells resulted in a sharp decrease of incorporation of 14C label from [14C]glucose into chitin, mannoprotein, and glucan. This effect, as well as the growth-inhibitory effect, was fully reversed by exogenous N-acetyl-D-glucosamine. Glucosamine-6-phosphate synthase was proved to be the only essential target for FMDP dipeptides. Scanning electron microscopy of C. albicans cells treated with L-norvalyl-FMDP revealed highly distorted, wrinkled, and collapsed forms. Cells formed long, bulbous chains, and partial lysis occurred. Images PMID:1901701

  6. Mechanism of action of anticandidal dipeptides containing inhibitors of glucosamine-6-phosphate synthase.

    PubMed

    Milewski, S; Andruszkiewicz, R; Kasprzak, L; Mazerski, J; Mignini, F; Borowski, E

    1991-01-01

    The mechanism of anticandidal action of novel synthetic dipeptides containing N3-(4-methoxyfumaroyl)-L-2,3-diaminopropanoic acid (FMDP) residues was shown to be consistent with the "warhead delivery" concept. FMDP dipeptides were shown to be transported into Candida albicans cells by the di-tripeptide permease and subsequently hydrolyzed by intracellular peptidases, especially aminopeptidase. The anticandidal activity of the particular FMDP dipeptide was influenced by the rate of its transport and, to a lower extent, by the intracellular cleavage rate. A high transport rate accompanied by a high cleavage rate resulted in the high anticandidal activity of L-norvalyl-FMDP. The strong growth-inhibitory effect of this compound was the consequence of inhibition of the enzyme glucosamine-6-phosphate synthase by the released FMDP. The action of L-norvalyl-FMDP on exponentially growing C. albicans cells resulted in a sharp decrease of incorporation of 14C label from [14C]glucose into chitin, mannoprotein, and glucan. This effect, as well as the growth-inhibitory effect, was fully reversed by exogenous N-acetyl-D-glucosamine. Glucosamine-6-phosphate synthase was proved to be the only essential target for FMDP dipeptides. Scanning electron microscopy of C. albicans cells treated with L-norvalyl-FMDP revealed highly distorted, wrinkled, and collapsed forms. Cells formed long, bulbous chains, and partial lysis occurred. PMID:1901701

  7. Structure-based virtual screening of hypothetical inhibitors of the enzyme longiborneol synthase-a potential target to reduce Fusarium head blight disease.

    PubMed

    Bresso, E; Leroux, V; Urban, M; Hammond-Kosack, K E; Maigret, B; Martins, N F

    2016-07-01

    Fusarium head blight (FHB) is one of the most destructive diseases of wheat and other cereals worldwide. During infection, the Fusarium fungi produce mycotoxins that represent a high risk to human and animal health. Developing small-molecule inhibitors to specifically reduce mycotoxin levels would be highly beneficial since current treatments unspecifically target the Fusarium pathogen. Culmorin possesses a well-known important synergistically virulence role among mycotoxins, and longiborneol synthase appears to be a key enzyme for its synthesis, thus making longiborneol synthase a particularly interesting target. This study aims to discover potent and less toxic agrochemicals against FHB. These compounds would hamper culmorin synthesis by inhibiting longiborneol synthase. In order to select starting molecules for further investigation, we have conducted a structure-based virtual screening investigation. A longiborneol synthase structural model is first built using homology modeling, followed by molecular dynamics simulations that provided the required input for a protein-ligand ensemble docking procedure. From this strategy, the three most interesting compounds (hits) were selected among the 25 top-ranked docked compounds from a library of 15,000 drug-like compounds. These putative inhibitors of longiborneol synthase provide a sound starting point for further studies involving molecular modeling coupled to biochemical experiments. This process could eventually lead to the development of novel approaches to reduce mycotoxin contamination in harvested grain. PMID:27324634

  8. The Design and Synthesis of Potent and Selective Inhibitors of Trypanosoma brucei Glycogen Synthase Kinase 3 for the Treatment of Human African Trypanosomiasis

    PubMed Central

    2014-01-01

    Glycogen synthase kinase 3 (GSK3) is a genetically validated drug target for human African trypanosomiasis (HAT), also called African sleeping sickness. We report the synthesis and biological evaluation of aminopyrazole derivatives as Trypanosoma brucei GSK3 short inhibitors. Low nanomolar inhibitors, which had high selectivity over the off-target human CDK2 and good selectivity over human GSK3β enzyme, have been prepared. These potent kinase inhibitors demonstrated low micromolar levels of inhibition of the Trypanosoma brucei brucei parasite grown in culture. PMID:25198388

  9. Catechol-based substrates of chalcone synthase as a scaffold for novel inhibitors of PqsD.

    PubMed

    Allegretta, Giuseppe; Weidel, Elisabeth; Empting, Martin; Hartmann, Rolf W

    2015-01-27

    A new strategy for treating Pseudomonas aeruginosa infections could be disrupting the Pseudomonas Quinolone Signal (PQS) quorum sensing (QS) system. The goal is to impair communication among the cells and, hence, reduce the expression of virulence factors and the formation of biofilms. PqsD is an essential enzyme for the synthesis of PQS and shares some features with chalcone synthase (CHS2), an enzyme expressed in Medicago sativa. Both proteins are quite similar concerning the size of the active site, the catalytic residues and the electrostatic surface potential at the entrance of the substrate tunnel. Hence, we evaluated selected substrates of the vegetable enzyme as potential inhibitors of the bacterial protein. This similarity-guided approach led to the identification of a new class of PqsD inhibitors having a catechol structure as an essential feature for activity, a saturated linker with two or more carbons and an ester moiety bearing bulky substituents. The developed compounds showed PqsD inhibition with IC50 values in the single-digit micromolar range. The binding mode of these compounds was investigated by Surface Plasmon Resonance (SPR) experiments revealing that their interaction with the protein is not influenced by the presence of the anthranilic acid bound to active site cysteine. Importantly, some compounds reduced the signal molecule production in cellulo. PMID:25437621

  10. Pharmacophore Modeling and Virtual Screening for Novel Acidic Inhibitors of Microsomal Prostaglandin E2 Synthase-1 (mPGES-1)

    PubMed Central

    2011-01-01

    Microsomal prostaglandin E2 synthase-1 (mPGES-1) catalyzes prostaglandin E2 formation and is considered as a potential anti-inflammatory pharmacological target. To identify novel chemical scaffolds active on this enzyme, two pharmacophore models for acidic mPGES-1 inhibitors were developed and theoretically validated using information on mPGES-1 inhibitors from literature. The models were used to screen chemical databases supplied from the National Cancer Institute (NCI) and the Specs. Out of 29 compounds selected for biological evaluation, nine chemically diverse compounds caused concentration-dependent inhibition of mPGES-1 activity in a cell-free assay with IC50 values between 0.4 and 7.9 μM, respectively. Further pharmacological characterization revealed that also 5-lipoxygenase (5-LO) was inhibited by most of these active compounds in cell-free and cell-based assays with IC50 values in the low micromolar range. Together, nine novel chemical scaffolds inhibiting mPGES-1 are presented that may possess anti-inflammatory properties based on the interference with eicosanoid biosynthesis. PMID:21466167

  11. Intracellular quantitative detection of human thymidylate synthase engagement with an unconventional inhibitor using tetracysteine-diarsenical-probe technology

    PubMed Central

    Ponterini, Glauco; Martello, Andrea; Pavesi, Giorgia; Lauriola, Angela; Luciani, Rosaria; Santucci, Matteo; Pelà, Michela; Gozzi, Gaia; Pacifico, Salvatore; Guerrini, Remo; Marverti, Gaetano; Costi, Maria Paola; D’Arca, Domenico

    2016-01-01

    Demonstrating a candidate drug’s interaction with its target protein in live cells is of pivotal relevance to the successful outcome of the drug discovery process. Although thymidylate synthase (hTS) is an important anticancer target protein, the efficacy of the few anti-hTS drugs currently used in clinical practice is limited by the development of resistance. Hence, there is an intense search for new, unconventional anti-hTS drugs; there are approximately 1600 ongoing clinical trials involving hTS-targeting drugs, both alone and in combination protocols. We recently discovered new, unconventional peptidic inhibitors of hTS that are active against cancer cells and do not result in the overexpression of hTS, which is a known molecular source of resistance. Here, we propose an adaptation of the recently proposed tetracysteine-arsenic-binding-motif technology to detect and quantitatively characterize the engagement of hTS with one such peptidic inhibitor in cell lysates. This new model can be developed into a test for high-throughput screening studies of intracellular target-protein/small-molecule binding. PMID:27250901

  12. Intracellular quantitative detection of human thymidylate synthase engagement with an unconventional inhibitor using tetracysteine-diarsenical-probe technology.

    PubMed

    Ponterini, Glauco; Martello, Andrea; Pavesi, Giorgia; Lauriola, Angela; Luciani, Rosaria; Santucci, Matteo; Pelà, Michela; Gozzi, Gaia; Pacifico, Salvatore; Guerrini, Remo; Marverti, Gaetano; Costi, Maria Paola; D'Arca, Domenico

    2016-01-01

    Demonstrating a candidate drug's interaction with its target protein in live cells is of pivotal relevance to the successful outcome of the drug discovery process. Although thymidylate synthase (hTS) is an important anticancer target protein, the efficacy of the few anti-hTS drugs currently used in clinical practice is limited by the development of resistance. Hence, there is an intense search for new, unconventional anti-hTS drugs; there are approximately 1600 ongoing clinical trials involving hTS-targeting drugs, both alone and in combination protocols. We recently discovered new, unconventional peptidic inhibitors of hTS that are active against cancer cells and do not result in the overexpression of hTS, which is a known molecular source of resistance. Here, we propose an adaptation of the recently proposed tetracysteine-arsenic-binding-motif technology to detect and quantitatively characterize the engagement of hTS with one such peptidic inhibitor in cell lysates. This new model can be developed into a test for high-throughput screening studies of intracellular target-protein/small-molecule binding. PMID:27250901

  13. Effects of an endogenous nitric oxide synthase inhibitor on phorbol myristate acetate-induced acute lung injury in rats.

    PubMed

    Lin, Hen I; Chu, Shi Jye; Wang, David; Chen, Hsing I; Hsu, Kang

    2003-01-01

    1. In the present study, we determined whether the endogenous nitric oxide (NO) synthase (NOS) inhibitor Nomega-nitro-l-arginine methyl ester (l-NAME) could ameliorate the acute lung injury (ALI) induced by phorbol myristate acetate (PMA) in rat isolated lung. 2. Typical ALI was induced successfully by PMA during 60 min of observation. At 2 micro g/kg, PMA elicited a significant increase in microvascular permeability (measured using the capillary filtration coefficient Kfc), lung weight gain, lung weight/bodyweight ratio, pulmonary arterial pressure (PAP) and protein concentration of bronchoalveolar lavage fluid. 3. Pretreatment with the NOS inhibitor l-NAME (5 mmol/L) significantly attenuated ALI. None of the parameters reflective of lung injury showed significant increase, except for PAP (P < 0.001). The addition of l-arginine (4 mmol/L) blocked the protective effective of l-NAME. Pretreatment with l-arginine exacerbated PMA-induced lung injury. 4. These data suggest that l-NAME significantly ameliorates ALI induced by PMA in rats, indicating that endogenous NO plays a key role in the development of lung oedema in PMA-induced lung injury. PMID:12859432

  14. Mutated KCNJ5 activates the acute and chronic regulatory steps in aldosterone production.

    PubMed

    Hattangady, Namita G; Karashima, Shigehiro; Yuan, Lucy; Ponce-Balbuena, Daniela; Jalife, José; Gomez-Sanchez, Celso E; Auchus, Richard J; Rainey, William E; Else, Tobias

    2016-07-01

    Somatic and germline mutations in the inward-rectifying K(+) channel (KCNJ5) are a common cause of primary aldosteronism (PA) in aldosterone-producing adenoma and familial hyperaldosteronism type III, respectively. Dysregulation of adrenal cell calcium signaling represents one mechanism for mutated KCNJ5 stimulation of aldosterone synthase (CYP11B2) expression and aldosterone production. However, the mechanisms stimulating acute and chronic production of aldosterone by mutant KCNJ5 have not been fully characterized. Herein, we defined the effects of the T158A KCNJ5 mutation (KCNJ5(T158A)) on acute and chronic regulation of aldosterone production using an adrenal cell line with a doxycycline-inducible KCNJ5(T158A) gene (HAC15-TRE-KCNJ5(T158A)). Doxycycline incubation caused a time-dependent increase in KCNJ5(T158A) and CYP11B2 mRNA and protein levels. Electrophysiological analyses confirm the loss of inward rectification and increased Na(+) permeability in KCNJ5(T158A)-expressing cells. KCNJ5(T158A) expression also led to the activation of CYP11B2 transcriptional regulators, NURR1 and ATF2. Acutely, KCNJ5(T158A) stimulated the expression of total and phosphorylated steroidogenic acute regulatory protein (StAR). KCNJ5(T158A) expression increased the synthesis of aldosterone and the hybrid steroids 18-hydroxycortisol and 18-oxocortisol, measured with liquid chromatography-tandem mass spectrometry (LC-MS/MS). All of these stimulatory effects of KCNJ5(T158A) were inhibited by the L-type Ca(2+) channel blocker, verapamil. Overall, KCNJ5(T158A)increases CYP11B2 expression and production of aldosterone, corticosterone and hybrid steroids by upregulating both acute and chronic regulatory events in aldosterone production, and verapamil blocks KCNJ5(T158A)-mediated pathways leading to aldosterone production. PMID:27099398

  15. Does Aldosterone Play a Significant Role for Regulation of Vascular Tone?

    PubMed

    Lyngsø, Kristina S; Assersen, Kasper; Dalgaard, Emil G; Skott, Ole; Jensen, Boye L; Hansen, Pernille B L

    2016-07-01

    Besides the well-known renal effects of aldosterone, the hormone is now known to have direct vascular effects. Clinical observations underline substantial adverse effects of aldosterone on cardiovascular function. The source of systemic circulating aldosterone is the adrenal gland zona glomerulosa cells through stimulus-secretion coupling involving depolarization, opening of L- and T-type calcium channels and aldosterone synthase activation. Local formation and release in peripheral tissues such as perivascular fat is recognized. Where does aldosterone affect the vasculature? Mineralocorticoid receptors (MRs) are present in endothelial and vascular smooth muscle cells, and MR-independent pathways are also involved. The vascular effects of aldosterone are complex, both concentration and temporal and spatial aspects are relevant. The acute response includes vasodilation through endothelial nitric oxide formation and vasoconstrictor effects through endothelial-contracting cyclooxygenase-derived factors and a changed calcium handling. The response to aldosterone can change within the same blood vessels depending on the exposure time and status of the endothelium. Chronic responses involve changed levels of reactive oxygen radicals, endothelial Na-influx and smooth muscle calcium channel expression. Furthermore, perivascular cells for example mast cells have also been suggested to participate in the chronic response. Moreover, the vascular effect of aldosterone depends on the status of the endothelium which is likely the cause of the very different responses to aldosterone and MR treatment observed in human studies going from increased to decreased flow depending on whether the patient had prior cardiovascular disease with endothelial dysfunction or not. A preponderance of constrictor versus dilator responses to aldosterone could therefore be involved in the detrimental vascular actions of the hormone in the setting of endothelial dysfunction and contribute to explain

  16. Aldosterone-stimulating somatic gene mutations are common in normal adrenal glands

    PubMed Central

    Nishimoto, Koshiro; Tomlins, Scott A.; Kuick, Rork; Cani, Andi K.; Giordano, Thomas J.; Hovelson, Daniel H.; Liu, Chia-Jen; Sanjanwala, Aalok R.; Edwards, Michael A.; Gomez-Sanchez, Celso E.; Nanba, Kazutaka; Rainey, William E.

    2015-01-01

    Primary aldosteronism (PA) represents the most common cause of secondary hypertension, but little is known regarding its adrenal cellular origins. Recently, aldosterone-producing cell clusters (APCCs) with high expression of aldosterone synthase (CYP11B2) were found in both normal and PA adrenal tissue. PA-causing aldosterone-producing adenomas (APAs) harbor mutations in genes encoding ion channels/pumps that alter intracellular calcium homeostasis and cause renin-independent aldosterone production through increased CYP11B2 expression. Herein, we hypothesized that APCCs have APA-related aldosterone-stimulating somatic gene mutations. APCCs were studied in 42 normal adrenals from kidney donors. To clarify APCC molecular characteristics, we used microarrays to compare the APCC transcriptome with conventional adrenocortical zones [zona glomerulosa (ZG), zona fasciculata, and zona reticularis]. The APCC transcriptome was most similar to ZG but with an enhanced capacity to produce aldosterone. To determine if APCCs harbored APA-related mutations, we performed targeted next generation sequencing of DNA from 23 APCCs and adjacent normal adrenal tissue isolated from both formalin-fixed, paraffin-embedded, and frozen tissues. Known aldosterone driver mutations were identified in 8 of 23 (35%) APCCs, including mutations in calcium channel, voltage-dependent, L-type, α1D-subunit (CACNA1D; 6 of 23 APCCs) and ATPase, Na+/K+ transporting, α1-polypeptide (ATP1A1; 2 of 23 APCCs), which were not observed in the adjacent normal adrenal tissue. Overall, we show three major findings: (i) APCCs are common in normal adrenals, (ii) APCCs harbor somatic mutations known to cause excess aldosterone production, and (iii) the mutation spectrum of aldosterone-driving mutations is different in APCCs from that seen in APA. These results provide molecular support for APCC as a precursor of PA. PMID:26240369

  17. Aldosterone-stimulating somatic gene mutations are common in normal adrenal glands.

    PubMed

    Nishimoto, Koshiro; Tomlins, Scott A; Kuick, Rork; Cani, Andi K; Giordano, Thomas J; Hovelson, Daniel H; Liu, Chia-Jen; Sanjanwala, Aalok R; Edwards, Michael A; Gomez-Sanchez, Celso E; Nanba, Kazutaka; Rainey, William E

    2015-08-18

    Primary aldosteronism (PA) represents the most common cause of secondary hypertension, but little is known regarding its adrenal cellular origins. Recently, aldosterone-producing cell clusters (APCCs) with high expression of aldosterone synthase (CYP11B2) were found in both normal and PA adrenal tissue. PA-causing aldosterone-producing adenomas (APAs) harbor mutations in genes encoding ion channels/pumps that alter intracellular calcium homeostasis and cause renin-independent aldosterone production through increased CYP11B2 expression. Herein, we hypothesized that APCCs have APA-related aldosterone-stimulating somatic gene mutations. APCCs were studied in 42 normal adrenals from kidney donors. To clarify APCC molecular characteristics, we used microarrays to compare the APCC transcriptome with conventional adrenocortical zones [zona glomerulosa (ZG), zona fasciculata, and zona reticularis]. The APCC transcriptome was most similar to ZG but with an enhanced capacity to produce aldosterone. To determine if APCCs harbored APA-related mutations, we performed targeted next generation sequencing of DNA from 23 APCCs and adjacent normal adrenal tissue isolated from both formalin-fixed, paraffin-embedded, and frozen tissues. Known aldosterone driver mutations were identified in 8 of 23 (35%) APCCs, including mutations in calcium channel, voltage-dependent, L-type, α1D-subunit (CACNA1D; 6 of 23 APCCs) and ATPase, Na(+)/(K+) transporting, α1-polypeptide (ATP1A1; 2 of 23 APCCs), which were not observed in the adjacent normal adrenal tissue. Overall, we show three major findings: (i) APCCs are common in normal adrenals, (ii) APCCs harbor somatic mutations known to cause excess aldosterone production, and (iii) the mutation spectrum of aldosterone-driving mutations is different in APCCs from that seen in APA. These results provide molecular support for APCC as a precursor of PA. PMID:26240369

  18. CT2108A and B: New fatty acid synthase inhibitors as antifungal agents.

    PubMed

    Laakso, Jodi A; Raulli, Robert; McElhaney-Feser, Gail E; Actor, Paul; Underiner, Ted L; Hotovec, Brian J; Mocek, Ursula; Cihlar, Ronald L; Broedel, Sheldon E

    2003-08-01

    A systematic screen for new natural products that displayed antifungal activity by inhibition of fungal fatty acid synthase (FAS) led to the discovery of two new fungal metabolites, designated CT2108A (1) and CT2108B (2). The metabolites were produced by Penicillium solitum (Westling) strain CT2108 and were classified as azaphilones. The structures of these new metabolites were determined using a variety of 1D and 2D NMR experiments, including COSY, HMQC, and HMBC. The chemical conversion of CT2108A to CT2108B was effected using WCl(6). The related metabolite, patulodin (3), was also isolated from the fermentation culture of this P. solitum isolate. Both new compounds inhibited fungal FAS, and neither was found to significantly inhibit human FAS activity. PMID:12932120

  19. Site-directed mutagenesis studies of acetylglutamate synthase delineate the site for the arginine inhibitor.

    PubMed

    Sancho-Vaello, Enea; Fernández-Murga, M Leonor; Rubio, Vicente

    2008-04-01

    N-acetyl-L-glutamate synthase (NAGS), the first enzyme of bacterial/plant arginine biosynthesis and an essential activator of the urea cycle in animals, is, respectively, arginine-inhibited and activated. Site-directed mutagenesis of recombinant Pseudomonas aeruginosa NAGS (PaNAGS) delineates the arginine site in the PaNAGS acetylglutamate kinase-like domain, and, by extension, in human NAGS. Key residues for glutamate binding are identified in the acetyltransferase domain. However, the acetylglutamate kinase-like domain may modulate glutamate binding, since one mutation affecting this domain increases the K(m) for glutamate. The effects on PaNAGS of two mutations found in human NAGS deficiency support the similarity of bacterial and human NAGSs despite their low sequence identity. PMID:18319063

  20. Developing dual and specific inhibitors of dimethylarginine dimethylaminohydrolase-1 and nitric oxide synthase: Toward a targeted polypharmacology to control nitric oxide†

    PubMed Central

    Wang, Yun; Monzingo, Arthur F.; Hu, Shougang; Schaller, Tera H.; Robertus, Jon D.; Fast, Walter

    2009-01-01

    Molecules that block nitric oxide's (NO) biosynthesis are of significant interest. For example, nitric oxide synthase (NOS) inhibitors have been suggested as anti-tumor therapeutics, as have inhibitors of dimethylarginine dimethylaminohydrolase (DDAH), an enzyme that catabolizes endogenous NOS inhibitors. Dual-targeted inhibitors hold promise as more effective reagents to block NO biosynthesis than single-targeted compounds. In this study, a small set of known NOS inhibitors are surveyed as inhibitors of recombinant human DDAH-1. From these, an alkylamidine scaffold is selected for homologation. Stepwise lengthening of one substituent converts an NOS-selective inhibitor into a dual-targeted NOS/DDAH-1 inhibitor and then into a DDAH-1 selective inhibitor, as seen in the inhibition constants of N5-(1-iminoethyl)-, N5-(1-iminopropyl)-, N5-(1-iminopentyl)- and N5-(1-iminohexyl)-l-ornithine for neuronal NOS (1.7, 3, 20, >1,900 μM, respectively) and DDAH-1 (990, 52, 7.5, 110 μM, respectively). A 1.9Å X-ray crystal structure of the N5-(1-iminopropyl)-l-ornithine : DDAH-1 complex indicates covalent bond formation between the inhibitor's amidino carbon and the active-site Cys274, and solution studies show reversible competitive inhibition, consistent with a reversible covalent mode of DDAH inhibition by alkylamidine inhibitors. These represent a versatile scaffold for the development of a targeted polypharmacological approach to control NO biosynthesis. PMID:19663506

  1. A Novel Glycogen Synthase Kinase-3 Inhibitor Optimized for Acute Myeloid Leukemia Differentiation Activity.

    PubMed

    Hu, Sophia; Ueda, Masumi; Stetson, Lindsay; Ignatz-Hoover, James; Moreton, Stephen; Chakrabarti, Amit; Xia, Zhiqiang; Karan, Goutam; de Lima, Marcos; Agrawal, Mukesh K; Wald, David N

    2016-07-01

    Standard therapies used for the treatment of acute myeloid leukemia (AML) are cytotoxic agents that target rapidly proliferating cells. Unfortunately, this therapeutic approach has limited efficacy and significant toxicity and the majority of AML patients still die of their disease. In contrast to the poor prognosis of most AML patients, most individuals with a rare subtype of AML, acute promyelocytic leukemia, can be cured by differentiation therapy using regimens containing all-trans retinoic acid. GSK3 has been previously identified as a therapeutic target in AML where its inhibition can lead to the differentiation and growth arrest of leukemic cells. Unfortunately, existing GSK3 inhibitors lead to suboptimal differentiation activity making them less useful as clinical AML differentiation agents. Here, we describe the discovery of a novel GSK3 inhibitor, GS87. GS87 was discovered in efforts to optimize GSK3 inhibition for AML differentiation activity. Despite GS87's dramatic ability to induce AML differentiation, kinase profiling reveals its high specificity in targeting GSK3 as compared with other kinases. GS87 demonstrates high efficacy in a mouse AML model system and unlike current AML therapeutics, exhibits little effect on normal bone marrow cells. GS87 induces potent differentiation by more effectively activating GSK3-dependent signaling components including MAPK signaling as compared with other GSK3 inhibitors. GS87 is a novel GSK3 inhibitor with therapeutic potential as a differentiation agent for non-promyelocytic AML. Mol Cancer Ther; 15(7); 1485-94. ©2016 AACR. PMID:27196775

  2. Biophysical Investigation of the Mode of Inhibition of Tetramic Acids, the Allosteric Inhibitors of Undecaprenyl Pyrophosphate Synthase

    PubMed Central

    2010-01-01

    Undecaprenyl pyrophosphate synthase (UPPS) catalyzes the consecutive condensation of eight molecules of isopentenyl pyrophosphate (IPP) with farnesyl pyrophosphate (FPP) to generate the C55 undecaprenyl pyrophosphate (UPP). It has been demonstrated that tetramic acids (TAs) are selective and potent inhibitors of UPPS, but the mode of inhibition was unclear. In this work, we used a fluorescent FPP probe to study possible TA binding at the FPP binding site. A photosensitive TA analogue was designed and synthesized for the study of the site of interaction of TA with UPPS using photo-cross-linking and mass spectrometry. The interaction of substrates with UPPS and with the UPPS·TA complex was investigated by protein fluorescence spectroscopy. Our results suggested that tetramic acid binds to UPPS at an allosteric site adjacent to the FPP binding site. TA binds to free UPPS enzyme but not to substrate-bound UPPS. Unlike Escherichia coli UPPS which follows an ordered substrate binding mechanism, Streptococcus pneumoniae UPPS appears to follow a random-sequential substrate binding mechanism. Only one substrate, FPP or IPP, is able to bind to the UPPS·TA complex, but the quaternary complex, UPPS·TA·FPP·IPP, cannot be formed. We propose that binding of TA to UPPS significantly alters the conformation of UPPS needed for proper substrate binding. As the result, substrate turnover is prevented, leading to the inhibition of UPPS catalytic activity. These probe compounds and biophysical assays also allowed us to quickly study the mode of inhibition of other UPPS inhibitors identified from a high-throughput screening and inhibitors produced from a medicinal chemistry program. PMID:20476728

  3. Biophysical investigation of the mode of inhibition of tetramic acids, the allosteric inhibitors of undecaprenyl pyrophosphate synthase.

    PubMed

    Lee, Lac V; Granda, Brian; Dean, Karl; Tao, Jianshi; Liu, Eugene; Zhang, Rui; Peukert, Stefan; Wattanasin, Sompong; Xie, Xiaoling; Ryder, Neil S; Tommasi, Ruben; Deng, Gejing

    2010-06-29

    Undecaprenyl pyrophosphate synthase (UPPS) catalyzes the consecutive condensation of eight molecules of isopentenyl pyrophosphate (IPP) with farnesyl pyrophosphate (FPP) to generate the C(55) undecaprenyl pyrophosphate (UPP). It has been demonstrated that tetramic acids (TAs) are selective and potent inhibitors of UPPS, but the mode of inhibition was unclear. In this work, we used a fluorescent FPP probe to study possible TA binding at the FPP binding site. A photosensitive TA analogue was designed and synthesized for the study of the site of interaction of TA with UPPS using photo-cross-linking and mass spectrometry. The interaction of substrates with UPPS and with the UPPS.TA complex was investigated by protein fluorescence spectroscopy. Our results suggested that tetramic acid binds to UPPS at an allosteric site adjacent to the FPP binding site. TA binds to free UPPS enzyme but not to substrate-bound UPPS. Unlike Escherichia coli UPPS which follows an ordered substrate binding mechanism, Streptococcus pneumoniae UPPS appears to follow a random-sequential substrate binding mechanism. Only one substrate, FPP or IPP, is able to bind to the UPPS.TA complex, but the quaternary complex, UPPS.TA.FPP.IPP, cannot be formed. We propose that binding of TA to UPPS significantly alters the conformation of UPPS needed for proper substrate binding. As the result, substrate turnover is prevented, leading to the inhibition of UPPS catalytic activity. These probe compounds and biophysical assays also allowed us to quickly study the mode of inhibition of other UPPS inhibitors identified from a high-throughput screening and inhibitors produced from a medicinal chemistry program. PMID:20476728

  4. Molecular basis of the inhibitor selectivity and insights into the feedback inhibition mechanism of citramalate synthase from Leptospira interrogans.

    PubMed

    Zhang, Peng; Ma, Jun; Zhang, Zilong; Zha, Manwu; Xu, Hai; Zhao, Guoping; Ding, Jianping

    2009-07-01

    LiCMS (Leptospira interrogans citramalate synthase) catalyses the first reaction of the isoleucine biosynthesis pathway in L. interrogans, the pathogen of leptospirosis. The catalytic reaction is regulated through feedback inhibition by its end product isoleucine. To understand the molecular basis of the high selectivity of the inhibitor and the mechanism of feedback inhibition, we determined the crystal structure of LiCMSC (C-terminal regulatory domain of LiCMS) in complex with isoleucine, and performed a biochemical study of the inhibition of LiCMS using mutagenesis and kinetic methods. LiCMSC forms a dimer of dimers in both the crystal structure and solution and the dimeric LiCMSC is the basic functional unit. LiCMSC consists of six beta-strands forming two anti-parallel beta-sheets and two alpha-helices and assumes a betaalphabeta three-layer sandwich structure. The inhibitor isoleucine is bound in a pocket at the dimer interface and has both hydrophobic and hydrogen-bonding interactions with several conserved residues of both subunits. The high selectivity of LiCMS for isoleucine over leucine is primarily dictated by the residues, Tyr430, Leu451, Tyr454, Ile458 and Val468, that form a hydrophobic pocket to accommodate the side chain of the inhibitor. The binding of isoleucine has inhibitory effects on the binding of both the substrate, pyruvate, and coenzyme, acetyl-CoA, in a typical pattern of K-type inhibition. The structural and biochemical data from the present study together suggest that the binding of isoleucine affects the binding of the substrate and coenzyme at the active site, possibly via conformational change of the dimer interface of the regulatory domain, leading to inhibition of the catalytic reaction. PMID:19351325

  5. Ceramide Production Mediates Aldosterone-Induced Human Umbilical Vein Endothelial Cell (HUVEC) Damages

    PubMed Central

    Zhang, Yumei; Pan, Yu; Bian, Zhixiang; Chen, Peihua; Zhu, Shijian; Gu, Huiyi; Guo, Liping; Hu, Chun

    2016-01-01

    Here, we studied the underlying mechanism of aldosterone (Aldo)-induced vascular endothelial cell damages by focusing on ceramide. We confirmed that Aldo (at nmol/L) inhibited human umbilical vein endothelial cells (HUVEC) survival, and induced considerable cell apoptosis. We propose that ceramide (mainly C18) production might be responsible for Aldo-mediated damages in HUVECs. Sphingosine-1-phosphate (S1P), an anti-ceramide lipid, attenuated Aldo-induced ceramide production and following HUVEC damages. On the other hand, the glucosylceramide synthase (GCS) inhibitor PDMP or the ceramide (C6) potentiated Aldo-induced HUVEC apoptosis. Eplerenone, a mineralocorticoid receptor (MR) antagonist, almost completely blocked Aldo-induced C18 ceramide production and HUVEC damages. Molecularly, ceramide synthase 1 (CerS-1) is required for C18 ceramide production by Aldo. Knockdown of CerS-1 by targeted-shRNA inhibited Aldo-induced C18 ceramide production, and protected HUVECs from Aldo. Reversely, CerS-1 overexpression facilitated Aldo-induced C18 ceramide production, and potentiated HUVEC damages. Together, these results suggest that C18 ceramide production mediates Aldo-mediated HUVEC damages. MR and CerS-1 could be the two signaling molecule regulating C18 ceramide production by Aldo. PMID:26788916

  6. Aldosterone-to-Renin Ratio Is Associated With Reduced 24-Hour Heart Rate Variability and QTc Prolongation in Hypertensive Patients

    PubMed Central

    Grübler, Martin R.; Kienreich, Katharina; Gaksch, Martin; Verheyen, Nicolas; Hartaigh, Bríain Ó.; Fahrleitner-Pammer, Astrid; März, Winfried; Schmid, Johannes; Oberreither, Eva-Maria; Wetzel, Julia; Catena, Cristiana; Sechi, Leonardo A.; Pieske, Burkert; Tomaschitz, Andreas; Pilz, Stefan

    2016-01-01

    Abstract Aldosterone is considered to exert direct effects on the myocardium and the sympathetic nervous system. Both QT time and heart rate (HR) variability (HRV) are considered to be markers of arrhythmic risk and autonomous dysregulation. In this study, we investigated the associations between aldosterone, QT time, and HRV in patients with arterial hypertension. We recruited 477 hypertensive patients (age: 60.2 ± 10.2 years; 52.3% females) with a mean systolic/diastolic 24-hour ambulatory blood pressure monitoring (ABPM) value of 128 ± 12.8/77.1 ± 9.2 mmHg and with a median of 2 (IQR: 1–3) antihypertensive agents. Patients were recruited from the outpatient clinic at the Department of Internal Medicine of the Medical University of Graz, Austria. Blood samples, 24-hour HRV derived from 24-hour blood pressure monitoring (ABPM) and ECG's were obtained. Plasma aldosterone and plasma renin concentrations were measured by means of a radioimmunoassay. Twenty-four-hour urine specimens were collected in parallel with ABPM. Mean QTc was 423.3 ± 42.0 milliseconds for males and 434.7 ± 38.3 milliseconds for females. Mean 24H-HR and 24H-HRV was 71.9 ± 9.8 and 10.0 ± 3.6 bpm, respectively. In linear regression analyses adjusted for age, sex, body mass index, ABPM, and current medication, aldosterone to active renin ratio (AARR) was significantly associated with the QTc interval, a marker for cardiac repolarization abnormalities (mean = 426 ± 42.4 milliseconds; β-coefficient = 0.121; P = 0.03) as well as with the 24-hour heart rate variability a surrogate for autonomic dysfunction (median = 9.67 [IQR = 7.38–12.22 bpm]; β-coefficient = −0.133; P = 0.01). In hypertensive patients, AARR is significantly related to QTc prolongation as well as HRV. Further studies investigating the effects of mineralocorticoid receptor blocker and aldosterone synthase inhibitors on QTc and HRV are warranted

  7. Pharmacological characterization of guanidinoethyldisulphide (GED), a novel inhibitor of nitric oxide synthase with selectivity towards the inducible isoform.

    PubMed Central

    Szabó, C.; Bryk, R.; Zingarelli, B.; Southan, G. J.; Gahman, T. C.; Bhat, V.; Salzman, A. L.; Wolff, D. J.

    1996-01-01

    1. Guanidines, amidines, S-alkylisothioureas, and recently, mercaptoalkylguanidines have been described as inhibitors of the generation of nitric oxide (NO) from L-arginine by NO synthases (NOS). We have recently demonstrated that guanidinoethyldisulphide (GED), formed from the dimerisation of mercaptoethylguanidine (MEG), is a novel inhibitor of nitric oxide synthases. Here we describe the pharmacological properties of GED on purified NOS isoforms, various cultured cell types, vascular ring preparations, and in endotoxin shock. 2. GED potently inhibited NOS activity of purified inducible NOS (iNOS), endothelial NOS (ecNOS), and brain NOS (bNOS) enzymes with Ki values of 4.3, 18 and 25 microM, respectively. Thus, GED has a 4 fold selectivity for iNOS over ecNOS at the enzyme level. The inhibitory effect of GED on ecNOS and iNOS was competitive vs. L-arginine and non-competitive vs. tetrahydrobiopterin. 3. Murine J774 macrophages, rat aortic smooth muscle cells, murine lung epithelial cells, and human intestinal DLD-1 cells were stimulated with appropriate mixtures of pro-inflammatory cytokines or bacterial lipopolysaccharide to express iNOS. In these cells, GED potently inhibited nitrite formation (EC50 values: 11, 9, 1 and 30 microM, respectively). This suggests that uptake of GED may be cell type and species-dependent. The inhibitory effect of GED on nitrite production was independent of whether GED was given together with immunostimulation or 6 h afterwards, indicating that GED does not interfere with the process of iNOS induction. 4. GED caused relaxations in the precontracted vascular ring preparations (EC50: 20 microM). Part of this relaxation was endothelium-dependent, but was not blocked by methylene blue (100 microM), an inhibitor of soluble guanylyl cyclase. In precontracted rings, GED enhanced the acetylcholine-induced, endothelium-dependent relaxations at 10 microM and caused a slight inhibition of the relaxations at 100 microM. The vascular studies

  8. Inhibitors of the Cysteine Synthase CysM with Antibacterial Potency against Dormant Mycobacterium tuberculosis.

    PubMed

    Brunner, Katharina; Maric, Selma; Reshma, Rudraraju Srilakshmi; Almqvist, Helena; Seashore-Ludlow, Brinton; Gustavsson, Anna-Lena; Poyraz, Ömer; Yogeeswari, Perumal; Lundbäck, Thomas; Vallin, Michaela; Sriram, Dharmarajan; Schnell, Robert; Schneider, Gunter

    2016-07-28

    Cysteine is an important amino acid in the redox defense of Mycobacterium tuberculosis, primarily as a building block of mycothiol. Genetic studies have implicated de novo cysteine biosynthesis in pathogen survival in infected macrophages, in particular for persistent M. tuberculosis. Here, we report on the identification and characterization of potent inhibitors of CysM, a critical enzyme in cysteine biosynthesis during dormancy. A screening campaign of 17 312 compounds identified ligands that bind to the active site with micromolar affinity. These were characterized in terms of their inhibitory potencies and structure-activity relationships through hit expansion guided by three-dimensional structures of enzyme-inhibitor complexes. The top compound binds to CysM with 300 nM affinity and displays selectivity over the mycobacterial homologues CysK1 and CysK2. Notably, two inhibitors show significant potency in a nutrient-starvation model of dormancy of Mycobacterium tuberculosis, with little or no cytotoxicity toward mammalian cells. PMID:27379713

  9. The fatty acid synthase inhibitor triclosan: repurposing an anti-microbial agent for targeting prostate cancer

    PubMed Central

    Sadowski, Martin C.; Pouwer, Rebecca H.; Gunter, Jennifer H.; Lubik, Amy A.; Quinn, Ronald J.; Nelson, Colleen C.

    2014-01-01

    Inhibition of FASN has emerged as a promising therapeutic target in cancer, and numerous inhibitors have been investigated. However, severe pharmacological limitations have challenged their clinical testing. The synthetic FASN inhibitor triclosan, which was initially developed as a topical antibacterial agent, is merely affected by these pharmacological limitations. Yet, little is known about its mechanism in inhibiting the growth of cancer cells. Here we compared the cellular and molecular effects of triclosan in a panel of eight malignant and non-malignant prostate cell lines to the well-known FASN inhibitors C75 and orlistat, which target different partial catalytic activities of FASN. Triclosan displayed a superior cytotoxic profile with a several-fold lower IC50 than C75 or orlistat. Structure-function analysis revealed that alcohol functionality of the parent phenol is critical for inhibitory action. Rescue experiments confirmed that end product starvation was a major cause of cytotoxicity. Importantly, triclosan, C75 and orlistat induced distinct changes to morphology, cell cycle, lipid content and the expression of key enzymes of lipid metabolism, demonstrating that inhibition of different partial catalytic activities of FASN activates different metabolic pathways. These finding combined with its well-documented pharmacological safety profile make triclosan a promising drug candidate for the treatment of prostate cancer. PMID:25313139

  10. Morlin, an inhibitor of cortical microtubule dynamics and cellulose synthase movement

    PubMed Central

    DeBolt, Seth; Gutierrez, Ryan; Ehrhardt, David W.; Melo, Carlos V.; Ross, Loretta; Cutler, Sean R.; Somerville, Christopher; Bonetta, Dario

    2007-01-01

    Morlin (7-ethoxy-4-methyl chromen-2-one) was discovered in a screen of 20,000 compounds for small molecules that cause altered cell morphology resulting in swollen root phenotype in Arabidopsis. Live-cell imaging of fluorescently labeled cellulose synthase (CESA) and microtubules showed that morlin acts on the cortical microtubules and alters the movement of CESA. Morlin caused a novel syndrome of cytoskeletal defects, characterized by cortical array reorientation and compromised rates of both microtubule elongation and shrinking. Formation of shorter and more bundled microtubules and detachment from the cell membrane resulted when GFP::MAP4-MBP was used to visualize microtubules during morlin treatment. Cytoskeletal effects were accompanied by a reduction in the velocity and redistribution of CESA complexes labeled with YFP::CESA6 at the cell cortex. Morlin caused no inhibition of mouse myoblast, bacterial or fungal cell proliferation at concentrations that inhibit plant cell growth. By contrast, morlin stimulated microtubule disassembly in cultured hippocampal neurons but had no significant effect on cell viability. Thus, morlin appears to be a useful new probe of the mechanisms that regulate microtubule cortical array organization and its functional interaction with CESA. PMID:17389408

  11. Allosteric Inhibitors at the Heterodimer Interface of Imidazole Glycerol Phosphate Synthase

    NASA Astrophysics Data System (ADS)

    Snoeberger, Ning-Shiuan Nicole

    Imidazole glycerol phosphate synthase (IGPS) from Thermotoga maritima is a heterodimeric enzyme composed of the HisH and HisF proteins. It is attractive as a pathological target since it is absent in mammals but found in plant and opportunistic human pathogens. IGPS was experimentally determined to be a V-type allosteric enzyme that is involved in an essential biosynthetic pathway of microorganisms. The enzyme catalyzes the hydrolysis of glutamine to form NH3 in the HisH protein, followed by cyclization of NH3 with N'-[(5'-phosphoribulosyl)imino]-5-aminoimidazole-4-carboxamide-ribonucleotide (PRFAR) in the HisF subunit, forming imidazole glycerol phosphate (IGP) and 5-aminoimidazole-4-carboxamide ribotide (AICAR) that enter the histidine and purine biosynthetic pathways. Allosteric motions induced upon the binding of the effector PRFAR to HisF propagate through the non-covalent HisH/HisF interface and synchronize catalytic activity at the two distant active sites. However, the nature of the allosteric pathway and the feasibility of manipulating signal transduction by using allosteric drug-like molecules remain to be established. Molecular docking studies of commercial drugs at the HisH/HisF interface were used to identify stable candidates with a potential allosteric effect on the reaction mechanism. Molecular dynamic simulations and calculations of NMR chemical shifts were combined to elucidate the allosteric pathway of IGPS.

  12. Fatty acid synthase inhibitors from plants: isolation, structure elucidation, and SAR studies.

    PubMed

    Li, Xing-Cong; Joshi, Alpana S; ElSohly, Hala N; Khan, Shabana I; Jacob, Melissa R; Zhang, Zhizheng; Khan, Ikhlas A; Ferreira, Daneel; Walker, Larry A; Broedel, Sheldon E; Raulli, Robert E; Cihlar, Ronald L

    2002-12-01

    Fatty acid synthase (FAS) has been identified as a potential antifungal target. FAS prepared from Saccharomyces cerevisiae was employed for bioactivity-guided fractionation of Chlorophora tinctoria,Paspalum conjugatum, Symphonia globulifera, Buchenavia parviflora, and Miconia pilgeriana. Thirteen compounds (1-13), including three new natural products (1, 4, 12), were isolated and their structures identified by spectroscopic interpretation. They represented five chemotypes, namely, isoflavones, flavones, biflavonoids, hydrolyzable tannin-related derivatives, and triterpenoids. 3'-Formylgenistein (1) and ellagic acid 4-O-alpha-l-rhamnopyranoside (9) were the most potent compounds against FAS, with IC(50) values of 2.3 and 7.5 microg/mL, respectively. Furthermore, 43 (14-56) analogues of the five chemotypes from our natural product repository and commercial sources were tested for their FAS inhibitory activity. Structure-activity relationships for some chemotypes were investigated. All these compounds were further evaluated for antifungal activity against Candida albicans and Cryptococcus neoformans. Although there were several antifungal compounds in the set, correlation between the FAS inhibitory activity and antifungal activity could not be defined. PMID:12502337

  13. A Fatal Combination: A Thymidylate Synthase Inhibitor with DNA Damaging Activity

    PubMed Central

    Ligasová, Anna; Strunin, Dmytro; Friedecký, David; Adam, Tomáš; Koberna, Karel

    2015-01-01

    2′-deoxy-5-ethynyluridine (EdU) has been previously shown to be a cell poison whose toxicity depends on the particular cell line. The reason is not known. Our data indicates that different efficiency of EdU incorporation plays an important role. The EdU-mediated toxicity was elevated by the inhibition of 2′-deoxythymidine 5′-monophosphate synthesis. EdU incorporation resulted in abnormalities of the cell cycle including the slowdown of the S phase and a decrease in DNA synthesis. The slowdown but not the cessation of the first cell division after EdU administration was observed in all of the tested cell lines. In HeLa cells, a 10 μM EdU concentration led to the cell death in the 100% of cells probably due to the activation of an intra S phase checkpoint in the subsequent S phase. Our data also indicates that this EdU concentration induces interstrand DNA crosslinks in HeLa cells. We suppose that these crosslinks are the primary DNA damage resulting in cell death. According to our results, the EdU-mediated toxicity is further increased by the inhibition of thymidylate synthase by EdU itself at its higher concentrations. PMID:25671308

  14. Design and synthesis of new potent inhibitors of farnesyl pyrophosphate synthase.

    PubMed

    Prokopenko, Volodymyr; Kovalishyn, Vasyl; Shevchuk, Michael; Kopernyk, Iryna; Metelytsia, Larysa; Romanenko, Vadim; Mogilevich, Sergey; Kukhar, Valery

    2014-06-01

    Predictive QSAR models for the inhibition activities of nitrogen-containing bisphosphonates (N-BPs) against farnesyl pyrophosphate synthase (FPPS) from Leishmania major (LeFPPS) were developed using a data set of 97 compounds. The QSAR models were developed through the use of Artificial Neural Networks and Random Forest learning procedures. The predictive ability of the models was tested by means of leave-one-out cross-validation; Q(2)values ranging from 0.45-0.79 were obtained for the regression models. The consensus prediction for the external evaluation set afforded high predictive power (Q(2)=0.76 for 35 compounds). The robustness of the QSAR models was also evaluated using a Y-randomization procedure. A small set of 6 new N-BPs were designed and synthesized applying the Michael reaction of tetrakis (trimethylsilyl) ethenylidene bisphosphonate with amines. The inhibition activities of these compounds against LeFPPS were predicted by the developed QSAR models and were found to correlate with their fungistatic activities against Candida albicans. The antifungal activities of N-BPs bearing n-butyl and cyclopropyl side chains exceeded the activities of Fluconazole, a triazole-containing antifungal drug. In conclusion, the N-BPs developed here present promising candidate drugs for the treatment of fungal diseases. PMID:24818603

  15. Isoeugenin, a Novel Nitric Oxide Synthase Inhibitor Isolated from the Rhizomes of Imperata cylindrica.

    PubMed

    An, Hyo-Jin; Nugroho, Agung; Song, Byong-Min; Park, Hee-Juhn

    2015-01-01

    Phytochemical studies on the constituents of the rhizomes of Imperata cylindrica (Gramineae) were performed using high-performance liquid chromatography (HPLC). We also aimed to search for any biologically active substance capable of inhibiting nitric oxide (NO) formation in lipopolysaccharide (LPS)-activated macrophage 264.7 cells, by testing four compounds isolated from this plant. Four compounds, including a new chromone, isoeugenin, along with ferulic acid, p-coumaric acid, and caffeic acid were isolated and identified by NMR spectroscopy. The structure of isoeugenin was determined as 7-hydroxy-5-methoxy-2-methylchromone by the 2D-NMR technique. Among the four compounds, isoeugenin has the lowest IC50 value on the inhibition of NO production in LPS-activated macrophage RAW264.7 cells (IC50, 9.33 μg/mL). In addition, isoeugenin significantly suppressed the LPS-induced expressions of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and proinflammatory cytokines mRNA levels. Taken together, these results suggest that the anti-inflammatory activity of isoeugenin is associated with the down-regulation of iNOS, COX-2, and pro-inflammatory cytokines in RAW264.7 cells. Accordingly, our results suggest that the new chromone isoegenin should be considered a potential treatment for inflammatory disease. PMID:26633331

  16. Pterin-sulfa conjugates as dihydropteroate synthase inhibitors and antibacterial agents.

    PubMed

    Zhao, Ying; Shadrick, William R; Wallace, Miranda J; Wu, Yinan; Griffith, Elizabeth C; Qi, Jianjun; Yun, Mi-Kyung; White, Stephen W; Lee, Richard E

    2016-08-15

    The sulfonamide class of antibiotics has been in continuous use for over 70years. They are thought to act by directly inhibiting dihydropteroate synthase (DHPS), and also acting as prodrugs that sequester pterin pools by forming dead end pterin-sulfonamide conjugates. In this study, eight pterin-sulfonamide conjugates were synthesized using a novel synthetic strategy and their biochemical and microbiological properties were investigated. The conjugates were shown to competitively inhibit DHPS, and inhibition was enhanced by the presence of pyrophosphate that is crucial to catalysis and is known to promote an ordering of the DHPS active site. The co-crystal structure of Yersinia pestis DHPS bound to one of the more potent conjugates revealed a mode of binding that is similar to that of the enzymatic product analog pteroic acid. The antimicrobial activities of the pterin-sulfonamide conjugates were measured against Escherichia coli in the presence and absence of folate precursors and dependent metabolites. These results show that the conjugates have appreciable antibacterial activity and act by an on target, anti-folate pathway mechanism rather than as simple dead end products. PMID:27423480

  17. Impaired learning in rats in a 14-unit T-maze by 7-nitroindazole, a neuronal nitric oxide synthase inhibitor, is attenuated by the nitric oxide donor, molsidomine.

    PubMed

    Meyer, R C; Spangler, E L; Patel, N; London, E D; Ingram, D K

    1998-01-01

    In previous experiments, it was demonstrated that systemic or central administration of the nitric oxide synthase (NO synthase) inhibitor, NG-nitro-L-arginine (N-Arg), produced dose-dependent learning impairments in rats in a 14-unit T-maze; and that sodium nitroprusside, a NO donor, could attenuate the impairment. Since N-Arg is not specific for neuronal NO synthase and produces hypertension, it is possible that effects on the cardiovasculature may have contributed to the impaired maze performance. In the present experiment, we have investigated the maze performance of 3-4 months old male Fischer-344 rats following treatment with 7-nitroindazole, a NO synthase inhibitor that is selective for neuronal NO synthase and does not produce hypertension. In addition, we examined the effects of the NO donor, molsidomine, which is much longer acting than sodium nitroprusside. Rats were pretrained to avoid footshock in a straight runway and received training in a 14-unit T-maze 24 h later. In an initial dose-response study, rats received intraperitoneal (i.p.) injections of either 7-nitroindazole (25, 50, or 65 mg/kg) or peanut oil 30 min prior to maze training. 7-nitroindazole produced significant, dose-dependent maze acquisition deficits, with 65 mg/kg producing the greatest learning impairment. This dose of 7-nitroindazole had no significant effect on systolic blood pressure. Following the dose-response study, rats were given i.p. injections of either 7-nitroindazole (70 mg/kg) plus saline, 7-nitroindazole (70 mg/kg) plus the NO donor, molsidomine (2 or 4 mg/kg), or peanut oil plus saline as controls. Both doses of molsidomine significantly attenuated the learning deficit induced by 7-nitroindazole relative to controls. These findings represent the first evidence that impaired learning produced by inhibition of neuronal NO synthase can be overcome by systemic administration of a NO donor. PMID:9489851

  18. Identification of inhibitors against Mycobacterium tuberculosis thiamin phosphate synthase, an important target for the development of anti-TB drugs.

    PubMed

    Khare, Garima; Kar, Ritika; Tyagi, Anil K

    2011-01-01

    Tuberculosis (TB) continues to pose a serious challenge to human health afflicting a large number of people throughout the world. In spite of the availability of drugs for the treatment of TB, the non-compliance to 6-9 months long chemotherapeutic regimens often results in the emergence of multidrug resistant strains of Mycobacterium tuberculosis adding to the precariousness of the situation. This has necessitated the development of more effective drugs. Thiamin biosynthesis, an important metabolic pathway of M. tuberculosis, is shown to be essential for the intracellular growth of this pathogen and hence, it is believed that inhibition of this pathway would severely affect the growth of M. tuberculosis. In this study, a comparative homology model of M. tuberculosis thiamin phosphate synthase (MtTPS) was generated and employed for virtual screening of NCI diversity set II to select potential inhibitors. The best 39 compounds based on the docking results were evaluated for their potential to inhibit the MtTPS activity. Seven compounds inhibited MtTPS activity with IC(50) values ranging from 20-100 µg/ml and two of these exhibited weak inhibition of M. tuberculosis growth with MIC(99) values being 125 µg/ml and 162.5 µg/ml while one compound was identified as a very potent inhibitor of M. tuberculosis growth with an MIC(99) value of 6 µg/ml. This study establishes MtTPS as a novel drug target against M. tuberculosis leading to the identification of new lead molecules for the development of antitubercular drugs. Further optimization of these lead compounds could result in more potent therapeutic molecules against Tuberculosis. PMID:21818324

  19. Fenofibrate inhibits aldosterone-induced apoptosis in adult rat ventricular myocytes via stress-activated kinase-dependent mechanisms

    PubMed Central

    De Silva, Deepa S.; Wilson, Richard M.; Hutchinson, Christoph; Ip, Peter C.; Garcia, Anthony G.; Lancel, Steve; Ito, Masa; Pimentel, David R.; Sam, Flora

    2009-01-01

    Aldosterone induces extracellular signal-regulated kinase (ERK)-dependent cardiac remodeling. Fenofibrate improves cardiac remodeling in adult rat ventricular myocytes (ARVM) partly via inhibition of aldosterone-induced ERK1/2 phosphorylation and inhibition of matrix metalloproteinases. We sought to determine whether aldosterone caused apoptosis in cultured ARVM and whether fenofibrate ameliorated the apoptosis. Aldosterone (1 μM) induced apoptosis by increasing terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling (TUNEL)-positive nuclei in ARVM. Spironolactone (100 nM), an aldosterone receptor antagonist, but not RU-486, a glucocorticoid receptor, inhibited aldosterone-mediated apoptosis, indicating that the mineralocorticoid receptor (MR) plays a role. SP-600125 (3 μM)—a selective inhibitor of c-Jun NH2-terminal kinase (JNK)—inhibited aldosterone-induced apoptosis in ARVM. Although aldosterone increased the expression of both stress-activated protein kinases, pretreatment with fenofibrate (10 μM) decreased aldosterone-mediated apoptosis by inhibiting only JNK phosphorylation and the aldosterone-induced increases in Bax, p53, and cleaved caspase-3 and decreases in Bcl-2 protein expression in ARVM. In vivo studies demonstrated that chronic fenofibrate (100 mg·kg body wt−1·day−1) inhibited myocardial Bax and increased Bcl-2 expression in aldosterone-induced cardiac hypertrophy. Similarly, eplerenone, a selective MR inhibitor, used in chronic pressure-overload ascending aortic constriction inhibited myocardial Bax expression but had no effect on Bcl-2 expression. Therefore, involvement of JNK MAPK-dependent mitochondrial death pathway mediates ARVM aldosterone-induced apoptosis and is inhibited by fenofibrate, a peroxisome proliferator-activated receptor (PPAR)α ligand. Fenofibrate mediates beneficial effects in cardiac remodeling by inhibiting programmed cell death and the stress-activated kinases. PMID:19395558

  20. Rapid effects of aldosterone in primary cultures of cardiomyocytes - do they suggest the existence of a membrane-bound receptor?

    PubMed

    Araujo, Carolina Morais; Hermidorff, Milla Marques; Amancio, Gabriela de Cassia Sousa; Lemos, Denise da Silveira; Silva, Marcelo Estáquio; de Assis, Leonardo Vinícius Monteiro; Isoldi, Mauro César

    2016-10-01

    Aldosterone acts on its target tissue through a classical mechanism or through the rapid pathway through a putative membrane-bound receptor. Our goal here was to better understand the molecular and biochemical rapid mechanisms responsible for aldosterone-induced cardiomyocyte hypertrophy. We have evaluated the hypertrophic process through the levels of ANP, which was confirmed by the analysis of the superficial area of cardiomyocytes. Aldosterone increased the levels of ANP and the cellular area of the cardiomyocytes; spironolactone reduced the aldosterone-increased ANP level and cellular area of cardiomyocytes. Aldosterone or spironolactone alone did not increase the level of cyclic 3',5'-adenosine monophosphate (cAMP), but aldosterone plus spironolactone led to increased cAMP level; the treatment with aldosterone + spironolactone + BAPTA-AM reduced the levels of cAMP. These data suggest that aldosterone-induced cAMP increase is independent of mineralocorticoid receptor (MR) and dependent on Ca(2+). Next, we have evaluated the role of A-kinase anchor proteins (AKAP) in the aldosterone-induced hypertrophic response. We have found that St-Ht31 (AKAP inhibitor) reduced the increased level of ANP which was induced by aldosterone; in addition, we have found an increase on protein kinase C (PKC) and extracellular signal-regulated kinase 5 (ERK5) activity when cells were treated with aldosterone alone, spironolactone alone and with a combination of both. Our data suggest that PKC could be responsible for ERK5 aldosterone-induced phosphorylation. Our study suggests that the aldosterone through its rapid effects promotes a hypertrophic response in cardiomyocytes that is controlled by an AKAP, being dependent on ERK5 and PKC, but not on cAMP/cAMP-dependent protein kinase signaling pathways. Lastly, we provide evidence that the targeting of AKAPs could be relevant in patients with aldosterone-induced cardiac hypertrophy and heart failure. PMID:27305962

  1. Counteraction by nitric oxide synthase inhibitor of neurochemical alterations of dopaminergic system in 6-OHDA-lesioned rats under L-DOPA treatment.

    PubMed

    Del-Bel, Elaine; Padovan-Neto, Fernando Eduardo; Szawka, Raphael Escorsim; da-Silva, Célia Aparecida; Raisman-Vozari, Rita; Anselmo-Franci, Janete; Romano-Dutra, Angélica Caroline; Guimaraes, Francisco Silveira

    2014-01-01

    Nitric oxide synthase inhibitors reduce L-3, (Del-Bel et al., Cell Mol Neurobiol 25(2):371-392, 2005) 4-dihydroxyphenylalanine (L-DOPA)-induced abnormal motor effects subsequent to depletion of dopaminergic neurons in rodents and non-human primates. The present study used quantitative high-performance liquid chromatography to analyze, for the first time, dopamine metabolism in striatum of rats in order to elucidate the mechanism of action of the nitric oxide synthase inhibitors. Adult male Wistar rats received unilateral microinjection of saline (sham) or 6-hydroxydopamine (6-OHDA-lesioned) in the medial forebrain bundle. Past 3 weeks, rats were treated during 21 days with L-DOPA/benserazide (30 mg/kg/7.5 mg/kg, respectively, daily). On the 22nd day rats received an intraperitoneal (i.p.) injection of either vehicle or 7-nitroindazole, a preferential neuronal nitric oxide synthase inhibitor before L-DOPA. Abnormal involuntary movements and rotarod test were assessed as behavioral correlate of motor responses. Lesion intensity was evaluated through tyrosine hydroxylase immunohystochemical reaction. Dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC), and an extent of dopamine striatal tissue levels/dopamine metabolism were measured in the striatum. Lesion with 6-OHDA decreased dopamine, DOPAC, and DOPAC/dopamine ratio in the lesioned striatum. L-DOPA treatment induced abnormal involuntary movements and increased DOPAC/dopamine ratio (nearly five times) in the lesioned striatum. L-DOPA-induced dyskinesia was mitigated by 7-nitroindazole, which also decreased dopamine turnover, dopamine and DOPAC levels. Our results revealed an almost two times increase in dopamine content in the non-lesioned striatum of 6-OHDA-lesioned rats. Reduction of striatal DOPAC/dopamine ratio in dyskinetic rats may suggest an increase in the dopamine availability. Our data confirm contribution of nitrergic transmission in the pathogenesis of L-DOPA-induced dyskinesia with potential

  2. Plasma concentrations of three methylated arginines, endogenous nitric oxide synthase inhibitors, in schizophrenic patients undergoing antipsychotic drug treatment.

    PubMed

    Nonaka-Hashida, Satoko; Sekine, Masae; Ozeki, Yuji; Fujii, Kumiko; Akiyama, Kazufumi; Shimoda, Kazutaka; Tsunoda, Makoto; Katane, Masumi; Saitoh, Yasuaki; Miyamoto, Tetsuya; Homma, Hiroshi

    2016-04-30

    Plasma concentration of three methylated arginines, endogenous nitric oxide synthase inhibitors, is not studied in schizophrenic patients. The purpose of this study was to determine plasma concentrations of N(G)-monomethyl-l-arginine (l-NMMA), N(G),N(G)-dimethyl-l-arginine (ADMA), N(G),N(G')-dimethyl-l-arginine (SDMA), and l-arginine in 56 male and 45 female schizophrenic patients undergoing antipsychotic drug treatment versus those of 39 male and 24 female healthy controls. Plasma concentrations of methylated arginines and l-arginine were measured using newly developed high performance liquid chromatography with fluorescence detection which we previously reported. Methylated arginine levels were slightly but significantly higher in schizophrenic patients. l-Arginine levels and the l-arginine/(ADMA+l-NMMA) ratio were higher in schizophrenic patients than in healthy controls. It is considered that pharmacological treatment of schizophrenic patients may lower methylated arginine levels that are increased by the disease, and increase l-arginine levels, eliciting an improvement in nitric oxide (NO) bioavailability. PMID:27086234

  3. Selective Nitric Oxide Synthase Inhibitor 7-Nitroindazole Protects against Cocaine-Induced Oxidative Stress in Rat Brain

    PubMed Central

    Vitcheva, Vessela; Simeonova, Rumyana; Kondeva-Burdina, Magdalena; Mitcheva, Mitka

    2015-01-01

    One of the mechanisms involved in the development of addiction, as well as in brain toxicity, is the oxidative stress. The aim of the current study was to investigate the effects of 7-nitroindazole (7-NI), a selective inhibitor of neuronal nitric oxide synthase (nNOS), on cocaine withdrawal and neurotoxicity in male Wistar rats. The animals were divided into four groups: control; group treated with cocaine (15 mg/kg−1, i.p., 7 days); group treated with 7-NI (25 mg/kg−1, i.p., 7 days); and a combination group (7-NI + cocaine). Cocaine repeated treatment resulted in development of physical dependence, judged by withdrawal symptoms (decreased locomotion, increased salivation and breathing rate), accompanied by an increased nNOS activity and oxidative stress. The latter was discerned by an increased formation of malondialdehyde (MDA), depletion of reduced glutathione (GSH) levels, and impairment of the enzymatic antioxidant defense system measured in whole brain. In synaptosomes, isolated from cocaine-treated rats, mitochondrial activity and GSH levels were also decreased. 7-NI administered along with cocaine not only attenuated the withdrawal, due to its nNOS inhibition, but also reversed both the GSH levels and antioxidant enzyme activities near control levels. PMID:26576217

  4. 5-imino-1,2,4-thiadiazoles: first small molecules as substrate competitive inhibitors of glycogen synthase kinase 3.

    PubMed

    Palomo, Valle; Perez, Daniel I; Perez, Concepcion; Morales-Garcia, Jose A; Soteras, Ignacio; Alonso-Gil, Sandra; Encinas, Arantxa; Castro, Ana; Campillo, Nuria E; Perez-Castillo, Ana; Gil, Carmen; Martinez, Ana

    2012-02-23

    Cumulative evidence strongly supports that glycogen synthase kinase-3 (GSK-3) is a pathogenic molecule when it is up-dysregulated, emerging as an important therapeutic target in severe unmet human diseases. GSK-3 specific inhibitors might be promising effective drugs for the treatment of devastating pathologies such as neurodegenerative diseases, stroke, and mood disorders. As GSK-3 has the ability to phosphorylate primed substrates, small molecules able to bind to this site should be perfect drug candidates, able to partially block the activity of the enzyme over some specific substrates. Here, we report substituted 5-imino-1,2,4-thiadiazoles as the first small molecules able to inhibit GSK-3 in a substrate competitive manner. These compounds are cell permeable, able to decrease inflammatory activation and to selectively differentiate neural stem cells. Overall, 5-imino-1,2,4-thiadiazoles are presented here as new molecules able to decrease neuronal cell death and to increase endogenous neurogenesis blocking the GSK-3 substrate site. PMID:22257026

  5. Property-based design of a glucosylceramide synthase inhibitor that reduces glucosylceramide in the brain[S

    PubMed Central

    Larsen, Scott D.; Wilson, Michael W.; Abe, Akira; Shu, Liming; George, Christopher H.; Kirchhoff, Paul; Showalter, H. D. Hollis; Xiang, Jianming; Keep, Richard F.; Shayman, James A.

    2012-01-01

    Synthesis inhibition is the basis for the treatment of type 1 Gaucher disease by the glucosylceramide synthase (GCS) inhibitor eliglustat tartrate. However, the extended use of eliglustat and related compounds for the treatment of glycosphingolipid storage diseases with CNS manifestations is limited by the lack of brain penetration of this drug. Property modeling around the D-threo-1-phenyl-2-decanoylamino-3-morpholino-propanol (PDMP) pharmacophore was employed in a search for compounds of comparable activity against the GCS but lacking P-glycoprotein (MDR1) recognition. Modifications of the carboxamide N-acyl group were made to lower total polar surface area and rotatable bond number. Compounds were screened for inhibition of GCS in crude enzyme and whole cell assays and for MDR1 substrate recognition. One analog, 2-(2,3-dihydro-1H-inden-2-yl)-N-((1R,2R)-1-(2,3-dihydrobenzo[b][1,4]dioxin-6-yl)-1-hydroxy-3-(pyrrolidin-1-yl)propan-2-yl)acetamide (CCG-203586), was identified that inhibited GCS at low nanomolar concentrations with little to no apparent recognition by MDR1. Intraperitoneal administration of this compound to mice for 3 days resulted in a significant dose dependent decrease in brain glucosylceramide content, an effect not seen in mice dosed in parallel with eliglustat tartrate. PMID:22058426

  6. Structures of prostacyclin synthase and its complexes with substrate analog and inhibitor reveal a ligand-specific heme conformation change.

    PubMed

    Li, Yi-Ching; Chiang, Chia-Wang; Yeh, Hui-Chun; Hsu, Pei-Yung; Whitby, Frank G; Wang, Lee-Ho; Chan, Nei-Li

    2008-02-01

    Prostacyclin synthase (PGIS) is a cytochrome P450 (P450) enzyme that catalyzes production of prostacyclin from prostaglandin H(2). PGIS is unusual in that it catalyzes an isomerization rather than a monooxygenation, which is typical of P450 enzymes. To understand the structural basis for prostacyclin biosynthesis in greater detail, we have determined the crystal structures of ligand-free, inhibitor (minoxidil)-bound and substrate analog U51605-bound PGIS. These structures demonstrate a stereo-specific substrate binding and suggest features of the enzyme that facilitate isomerization. Unlike most microsomal P450s, where large substrate-induced conformational changes take place at the distal side of the heme, conformational changes in PGIS are observed at the proximal side and in the heme itself. The conserved and extensive heme propionate-protein interactions seen in all other P450s, which are largely absent in the ligand-free PGIS, are recovered upon U51605 binding accompanied by water exclusion from the active site. In contrast, when minoxidil binds, the propionate-protein interactions are not recovered and water molecules are largely retained. These findings suggest that PGIS represents a divergent evolution of the P450 family, in which a heme barrier has evolved to ensure strict binding specificity for prostaglandin H(2), leading to a radical-mediated isomerization with high product fidelity. The U51605-bound structure also provides a view of the substrate entrance and product exit channels. PMID:18032380

  7. Phytotoxicity of Acetohydroxyacid Synthase Inhibitors Is Not Due to Accumulation of 2-Ketobutyrate and/or 2-Aminobutyrate.

    PubMed Central

    Shaner, D. L.; Singh, B. K.

    1993-01-01

    Acetohydroxyacid synthase (AHAS) is the site of action of herbicides of different chemical classes, such as imidazolinones, sulfonylureas, and triazolopyrimidines. Inhibition of AHAS causes the accumulation of 2-ketobutyrate (2-KB) and 2-aminobutyrate (2-AB) (the transamination product of 2-KB), and it has been proposed that the phytotoxicity of these inhibitors is due to this accumulation. Experiments were done to determine the relationship between accumulation of 2-KB and 2-AB and the phytotoxicity of imazaquin to maize (Zea mays). Imazaquin concentrations that inhibit growth of maize plants also cause the accumulation of 2-KB and 2-AB in the shoots. Supplementation of imazaquin-treated plants with isoleucine reduced the pools of 2-KB and 2-AB in the plant but did not protect plants from the growth inhibitory effects of imazaquin. Conversely, feeding 2-AB to maize plants increased 2-KB and 2-AB pools to much higher levels than those observed in imazaquin-treated plants, yet such high pools of 2-KB and 2-AB in the plant had no significant effect on growth. These results conclusively demonstrate that growth inhibition following imazaquin treatment is not due to accumulation of 2-KB and/or 2-AB in plants. Changes in the amino acid profiles after treatment with imazaquin suggest that starvation for the branched-chain amino acids may be the primary cause of growth retardation of maize. PMID:12232015

  8. Influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation, regulation and organisation of photosynthesis in Solanum nigrum.

    PubMed

    Riethmuller-Haage, Ingrid; Bastiaans, Lammert; Harbinson, Jeremy; Kempenaar, Corné; Kropff, Martin J

    2006-06-01

    The influence of the acetolactate synthase inhibitor metsulfuron-methyl on the operation of the photosynthetic apparatus was examined on 4-weeks-old climate chamber-grown Solanum nigrum plant. To have an indication on the relative performance of the photosynthetic apparatus of ALS-treated plants, the level of carbon dioxide (CO(2)) fixation, the relative quantum efficiency of photosystem I (Phi(PSI)) or photosystem II (Phi(PSII)) electron transport and leaf chlorophyll content were assessed for both control and treated plants at 2, 4 and 7 days after application of the herbicide. Results indicated a progressive inhibition of the level of CO(2) fixation, the relative quantum efficiency of photosystem I (Phi(PSI)) and II (Phi(PSII)) electron transport and the leaf chlorophyll content already 2 days after application of the herbicide. The linear relationship between the photosystem I and II was unaltered by herbicidal treatment and was sustained under conditions where large changes in pigment composition of the leaves occurred. It appears that the stress-induced loss of leaf chlorophyll is not a catastrophic process but rather is the consequence of a well-organised breakdown of components. Under photorespiratory and non-photorespiratory conditions, the relationship between the index of electron transport flow through photosystem I and II and the rate of CO(2) fixation is altered so that electron transport becomes less efficient at driving CO(2) fixation. PMID:16691366

  9. Selective Nitric Oxide Synthase Inhibitor 7-Nitroindazole Protects against Cocaine-Induced Oxidative Stress in Rat Brain.

    PubMed

    Vitcheva, Vessela; Simeonova, Rumyana; Kondeva-Burdina, Magdalena; Mitcheva, Mitka

    2015-01-01

    One of the mechanisms involved in the development of addiction, as well as in brain toxicity, is the oxidative stress. The aim of the current study was to investigate the effects of 7-nitroindazole (7-NI), a selective inhibitor of neuronal nitric oxide synthase (nNOS), on cocaine withdrawal and neurotoxicity in male Wistar rats. The animals were divided into four groups: control; group treated with cocaine (15 mg/kg(-1), i.p., 7 days); group treated with 7-NI (25 mg/kg(-1), i.p., 7 days); and a combination group (7-NI + cocaine). Cocaine repeated treatment resulted in development of physical dependence, judged by withdrawal symptoms (decreased locomotion, increased salivation and breathing rate), accompanied by an increased nNOS activity and oxidative stress. The latter was discerned by an increased formation of malondialdehyde (MDA), depletion of reduced glutathione (GSH) levels, and impairment of the enzymatic antioxidant defense system measured in whole brain. In synaptosomes, isolated from cocaine-treated rats, mitochondrial activity and GSH levels were also decreased. 7-NI administered along with cocaine not only attenuated the withdrawal, due to its nNOS inhibition, but also reversed both the GSH levels and antioxidant enzyme activities near control levels. PMID:26576217

  10. Nitric Oxide Synthase Inhibitors Prevent the Growth-inhibiting Effects of Quinpirole

    PubMed Central

    Nickla, Debora L.; Lee, Laimeng; Totonelly, Kristen

    2014-01-01

    Purpose Both dopamine and nitric oxide (NO) have been implicated in the signal cascade mediating ocular growth inhibition. If both are part of the same pathway, which precedes the other? We tested the hypothesis that dopamine acts upstream of NO, by using two NOS inhibitors in combination with the dopamine agonist quinpirole, and measuring the effects on ocular growth rate. Methods Chicks wore −10 D lenses or diffusers (FD) for 4d starting at age 13d. Experimental eyes received daily 20 μl injections of the following: Quinpirole: lens: n=12; FD: n=20; n-ω-propyl-L-arginine (n-PLA): lens: n=6; FD: n=4; quinpirole + n-PLA: lens: n=17; FD: n=19; quinpirole + L-NIO: lens: n=12; FD: n=12. Saline injections were done as controls. High frequency ultrasonography was done at the start, and on day 5, prior to injections and 3 hours later. Refractions were measured on day5. Results As expected, quinpirole prevented the development of axial myopia in both paradigms. When quinpirole was combined with either NOS inhibitor, however, eyes became myopic compared to quinpirole (FD: n-PLA: −5.9D vs −3.4D; L-NIO: −5.8D vs −3.4D; LENS: n-PLA: −3.5D vs −0.4D; p<0.05 for all; L-NIO was not significant). This was the result of a dis-inhibition of vitreous chamber growth vs quinpirole (FD: n-PLA: 401 vs 275 μm/4d; L-NIO: 440 vs 275 μm/4d; LENS: n-PLA: 407 vs 253/4d; L-NIO: 403 vs 253 μm/4d; p<0.05). Only n-PLA prevented the quinpirole-induced choroidal thickening in lens-wearing eyes (0 vs 31 μm/3hr; p<0.05). Choroidal thickening was not inhibited by either drug in FD eyes. Conclusions Dopamine acts upstream of NO and the choroidal response in the signal cascade mediating ocular growth inhibition in both form deprivation and negative lens wear. That neither NOS inhibitor inhibits choroidal thickening in FD eyes suggests that the choroidal mechanisms differ in the two paradigms. PMID:24061155

  11. Discovery of Isonicotinamides as Highly Selective, Brain Penetrable, and Orally Active Glycogen Synthase Kinase-3 Inhibitors.

    PubMed

    Luo, Guanglin; Chen, Ling; Burton, Catherine R; Xiao, Hong; Sivaprakasam, Prasanna; Krause, Carol M; Cao, Yang; Liu, Nengyin; Lippy, Jonathan; Clarke, Wendy J; Snow, Kimberly; Raybon, Joseph; Arora, Vinod; Pokross, Matt; Kish, Kevin; Lewis, Hal A; Langley, David R; Macor, John E; Dubowchik, Gene M

    2016-02-11

    GSK-3 is a serine/threonine kinase that has numerous substrates. Many of these proteins are involved in the regulation of diverse cellular functions, including metabolism, differentiation, proliferation, and apoptosis. Inhibition of GSK-3 may be useful in treating a number of diseases including Alzheimer's disease (AD), type II diabetes, mood disorders, and some cancers, but the approach poses significant challenges. Here, we present a class of isonicotinamides that are potent, highly kinase-selective GSK-3 inhibitors, the members of which demonstrated oral activity in a triple-transgenic mouse model of AD. The remarkably high kinase selectivity and straightforward synthesis of these compounds bode well for their further exploration as tool compounds and therapeutics. PMID:26751161

  12. Spontaneous rearrangement of aminoalkylisothioureas into mercaptoalkylguanidines, a novel class of nitric oxide synthase inhibitors with selectivity towards the inducible isoform.

    PubMed Central

    Southan, G. J.; Zingarelli, B.; O'Connor, M.; Salzman, A. L.; Szabó, C.

    1996-01-01

    1. The generation of nitric oxide (NO) from L-arginine by NO synthases (NOS) can be inhibited by guanidines, amidines and S-alkylisothioureas. Unlike most L-arginine based inhibitors, however, some guanidines and S-alkylisothioureas, in particular aminoethylisothiourea (AETU), show selectivity towards the inducible isoform (iNOS) over the constitutive isoforms (endothelial, ecNOS and brain isoform, bNOS) and so may be of therapeutic benefit. In the present study we have investigated the effects of AETU and other aminoalkylisothioureas on the activities of iNOS, ecNOS and bNOS. 2. AETU, aminopropylisothiourea (APTU) and their derivatives containing alkyl substituents on one of the amidino nitrogens, potently inhibit nitrite formation by immunostimulated J774 macrophages (a model of iNOS activity) with EC50 values ranging from 6-30 microM (EC50 values for NG-methyl-L-arginine (L-NMA) and NG-nitro-L-arginine were 159 and > 1000 microM, respectively). The inhibitory effects of these aminoalkylisothioureas (AATUs) were attentuated by L-arginine in the incubation medium, indicating that these agents may complete with L-arginine for its binding site on NOS. 3. The above AATUs undergo chemical conversion in neutral or basic solution (pH 7 or above) as indicated by (1) the disappearance of AATUs from solution as measured by h.p.l.c., (2) the generation of free thiols not previously present and (3) the isolation of species (as picrate and flavianate salts) from neutral or basic solutions of AATUs that are different from those obtained from acid solutions. 4. Mercaptoalkylguanidines (MAGs) were prepared and shown to be potent inhibitors of iNOS activity with EC50s comparable to those of their isomeric AATUs. 5. These findings suggest that certain AATUs exert their potent inhibitory effects through intramolecular rearrangement to mercaptoalkylguanidines (MAGs) at physiological pH. Those AATUs not capable of such rearrangement do not exhibit the same degree of inhibition of i

  13. Spontaneous rearrangement of aminoalkylisothioureas into mercaptoalkylguanidines, a novel class of nitric oxide synthase inhibitors with selectivity towards the inducible isoform.

    PubMed

    Southan, G J; Zingarelli, B; O'Connor, M; Salzman, A L; Szabó, C

    1996-02-01

    1. The generation of nitric oxide (NO) from L-arginine by NO synthases (NOS) can be inhibited by guanidines, amidines and S-alkylisothioureas. Unlike most L-arginine based inhibitors, however, some guanidines and S-alkylisothioureas, in particular aminoethylisothiourea (AETU), show selectivity towards the inducible isoform (iNOS) over the constitutive isoforms (endothelial, ecNOS and brain isoform, bNOS) and so may be of therapeutic benefit. In the present study we have investigated the effects of AETU and other aminoalkylisothioureas on the activities of iNOS, ecNOS and bNOS. 2. AETU, aminopropylisothiourea (APTU) and their derivatives containing alkyl substituents on one of the amidino nitrogens, potently inhibit nitrite formation by immunostimulated J774 macrophages (a model of iNOS activity) with EC50 values ranging from 6-30 microM (EC50 values for NG-methyl-L-arginine (L-NMA) and NG-nitro-L-arginine were 159 and > 1000 microM, respectively). The inhibitory effects of these aminoalkylisothioureas (AATUs) were attentuated by L-arginine in the incubation medium, indicating that these agents may complete with L-arginine for its binding site on NOS. 3. The above AATUs undergo chemical conversion in neutral or basic solution (pH 7 or above) as indicated by (1) the disappearance of AATUs from solution as measured by h.p.l.c., (2) the generation of free thiols not previously present and (3) the isolation of species (as picrate and flavianate salts) from neutral or basic solutions of AATUs that are different from those obtained from acid solutions. 4. Mercaptoalkylguanidines (MAGs) were prepared and shown to be potent inhibitors of iNOS activity with EC50s comparable to those of their isomeric AATUs. 5. These findings suggest that certain AATUs exert their potent inhibitory effects through intramolecular rearrangement to mercaptoalkylguanidines (MAGs) at physiological pH. Those AATUs not capable of such rearrangement do not exhibit the same degree of inhibition of i

  14. Modulation of aldosterone levels by -344 C/T CYP11B2 polymorphism and spironolactone use in resistant hypertension.

    PubMed

    Fontana, Vanessa; de Faria, Ana Paula Cabral; Barbaro, Natália Ruggeri; Sabbatini, Andréa Rodrigues; Modolo, Rodrigo; Lacchini, Riccardo; Moreno, Heitor

    2014-03-01

    Interindividual variability in plasma aldosterone levels comprises environmental and genetic sources. Increased aldosterone levels have been associated with higher risk of hypertension and target-organ damage related to hypertension. Aldosterone excess and intravascular volume expansion are implicated in pathophysiology of resistant hypertension (RH). We sought to investigate whether -344 C/T polymorphism (rs1799998) in aldosterone synthase gene (CYP11B2) is associated with plasma aldosterone levels in patients with resistant hypertension. Sixty-two patients with resistant hypertension were enrolled in this cross-sectional study. Genotypes were obtained by allelic discrimination assay using real time polymerase chain reaction. Multivariable linear regression was used to identify whether TT genotype was a predictor of aldosterone levels. No differences in clinical and laboratorial parameters were found among genotype groups. We found an additive effect of the T allele on plasma aldosterone concentration in RH. Also, there was higher aldosterone levels in TT homozygous under use of spironolactone compared with C carriers and compared with TT subjects who was not under use of spironolactone. TT genotype and the use of spironolactone were significant predictors of aldosterone levels in RH subjects. Plasma aldosterone concentration is significantly associated with -344 C/T CYP11B2 polymorphism and with the treatment with spironolactone in resistant hypertensive subjects. PMID:24388430

  15. Primary aldosteronism and pregnancy.

    PubMed

    Landau, Ester; Amar, Laurence

    2016-06-01

    Hypertension (HT) is a complication of 8% of all pregnancies and 10% of HT cases are due to primary aldosteronism (PA). There is very little data on PA and pregnancy. Given the changes in the renin angiotensin system during pregnancy, the diagnosis of PA is difficult to establish during gestation. It may be suspected in hypertensive patients with hypokalemia. A comprehensive literature review identified reports covering 40 pregnancies in patients suffering from PA. Analysis of these cases shows them to be high-risk pregnancies leading to maternal and fetal complications. Pregnancy must be programmed, and if the patient has a unilateral form of PA, adrenalectomy should be performed prior to conception. It is customary to stop spironolactone prior to conception and introduce antihypertensive drugs that present no risk of teratogenicity. When conventional antihypertensive drugs used during pregnancy fail to control high blood pressure, diuretics, including potassium-sparing diuretics may be prescribed. Adrenalectomy can be considered during the second trimester of pregnancy exclusively in cases of refractory hypertension. A European retrospective study is currently underway to collect a larger number of cases. PMID:27156905

  16. Disabled-2 is expressed in adrenal zona glomerulosa and is involved in aldosterone secretion.

    PubMed

    Romero, Damian G; Yanes, Licy L; de Rodriguez, Angela F; Plonczynski, Maria W; Welsh, Bronwyn L; Reckelhoff, Jane F; Gomez-Sanchez, Elise P; Gomez-Sanchez, Celso E

    2007-06-01

    The differentiation of the adrenal cortex into functionally specific zones is probably due to differential temporal gene expression during fetal growth, development, and adulthood. In our search for adrenal zona glomerulosa-specific genes, we found that Disabled-2 (Dab2) is expressed in the zona glomerulosa of the rat adrenal gland using a combination of laser capture microdissection, mRNA amplification, cDNA microarray hybridization, and real-time RT-PCR. Dab2 is an alternative spliced mitogen-regulated phosphoprotein with features of an adaptor protein and functions in signal transduction, endocytosis, and tissue morphogenesis during embryonic development. We performed further studies to analyze adrenal Dab2 localization, regulation, and role in aldosterone secretion. We found that Dab2 is expressed in the zona glomerulosa and zona intermedia of the rat adrenal cortex. Low-salt diet treatment increased Dab2-long isoform expression at the mRNA and protein level in the rat adrenal gland, whereas high-salt diet treatment did not cause any significant modification. Angiotensin II infusion caused a transient increase in both Dab2 isoform mRNAs in the rat adrenal gland. Dab2 overexpression in H295R human adrenocortical cells caused an increase in aldosterone synthase expression and up-regulated aldosterone secretion under angiotensin II-stimulated conditions. In conclusion, Dab2 is an adrenal gland zona glomerulosa- and intermedia-expressed gene that is regulated by aldosterone secretagogues such as low-salt diet or angiotensin II and is involved in aldosterone synthase expression and aldosterone secretion. Dab2 may therefore be a modulator of aldosterone secretion and be involved in mineralocorticoid secretion abnormalities. PMID:17303656

  17. Ginsenoside Rg1 reduces aldosterone-induced autophagy via the AMPK/mTOR pathway in NRK-52E cells.

    PubMed

    Wang, Li; Mao, Nan; Tan, Rui-Zhi; Wang, Hong-Lian; Wen, Ji; Liu, Yu-Hang; Furhad, Md; Fan, Jun-Ming

    2015-08-01

    Aldosterone is a steroid hormone secreted from the adrenal cortex, which regulates blood pressure. Higher concentrations of aldosterone can cause several diseases, including hypertension, diabetic nephropathy and chronic kidney disease. Previous reports have demonstrated that aldosterone has a pathogenic role in renal injury via reactive oxygen species (ROS), which involves the regulation of autophagy. However, whether aldosterone can induce autophagy in renal tubular cells remains to be elucidated. In the present study, elevated autophagy was observed in rat renal tubular NRK-52E cells exposed to aldosterone, which was demonstrated by the increased number of autophagosomes, conversion of LC3-I to LC3-II and the expression of Beclin-1. The enhanced autophagy was accompanied by increased production of intracellular ROS, which was reversed by N-acetylcysteine, a specific inhibitor of ROS signaling. Furthermore, treatment with ginsenoside Rg1 reduced the aldosterone-induced autophagy and production of ROS, possibly through reducing the phosphorylation of AMPK and preserving mTOR activity. These findings demonstrated that aldosterone promoted ROS generation and increased autophagy in the NRK-52E cells. Ginsenoside Rg1 effectively relieved aldosterone-induced oxidative stress and abnormal autophagy, suggesting that Rg1 may be used as a potential therapeutic drug to inhibit the renal injury, which is induced by aldosterone. PMID:26063203

  18. OP33GLYCOGEN SYNTHASE KINASE INHIBITORS REDUCE 3D MIGRATION OF PATIENT DERIVED GLIOBLASTOMA MULTIFORME STEM CELLS

    PubMed Central

    Tams, Daniel M.; Murray, Clare; Barry, Simon T.; Lawler, Sean; Bruning-Richardson, Anke; Short, Susan

    2014-01-01

    INTRODUCTION: Glioblastoma multiforme (GBM) is a fast growing, highly invasive malignant brain tumour. Inhibition of tumour cell migration into normal brain tissue represents a major target for treatment. Glycogen synthase kinase (GSK-3) inhibition has been associated with reduced GBM invasion in in vitro and in vivo models. Targeting this pathway with established and/or novel drugs may elucidate more effective treatment combinations. METHOD: The effect of GSK-3 inhibitors BIO, AZD2858, AZ1293 and AZ1080 on GBM migration was assessed in patient derived GBM stem cells (GBM-1) and two established cell lines (U251 and U87) using a 3D collagen based assay. Multiple drug concentrations were investigated with up to 72 hours exposure. A migration index was determined using aggregate core size and cell migration area. Immunohistochemistry and immunocytochemistry were used to assess cell morphology and cytoskeletal changes. RESULTS: All compounds inhibit migration in this model. AZD2858 was the most potent, causing significant effects at 1 micro molar. All compounds were cytotoxic at between 10 and 20 micro molar. Cytoskeletal and nuclear abnormalities were noted following drug exposure in all cell lines. These data suggest that possible mechanisms for the anti-migratory effect of these compounds include effects on F-actin localization and microtubule polarity. Inhibition of migration and cell architecture changes occurred at non-toxic doses. CONCLUSION: Inhibition of GSK3 significantly reduced migration of this highly invasive tumour. It is evident from these data that inhibiting the complex biological mechanisms driven by GSK3 may aid treatment of GBM through a number of different mechanisms.

  19. Selective enhancement of the uptake and bioactivity of a TAT-conjugated peptide inhibitor of glycogen synthase kinase-3.

    PubMed

    Manceur, Aziza P; Driscoll, Brandon D; Sun, Wei; Audet, Julie

    2009-03-01

    The use of cell-penetrating peptides as transduction vectors is a promising approach to deliver peptides and proteins into cells. However, the uptake and bioavailability of trans-activating transcriptor (TAT)-conjugated molecules vary depending on the cell type and the cargo. This study aimed to determine whether a low-voltage electrical pulse can enhance the TAT-mediated delivery of peptide cargoes in different cell types. In TF-1 and mouse embryonic stem cells, the uptake of a novel detachable TAT-conjugated glycogen synthase kinase-3 (GSK-3) peptide inhibitor was enhanced by an order of magnitude without affecting the cell viability. A similar increase in uptake was achieved in primary mouse bone marrow cells while maintaining >80% of their viability. Interestingly, under these low-voltage conditions, the uptake of a control peptide not conjugated to TAT was not significantly increased. A T-cell factor/lymphoid enhancer factor (TCF/LEF) luciferase reporter assay was also used to assess the bioactivity of the TAT construct. The results indicated that cells loaded with a low-voltage electrical pulse had a twofold increase in TCF/LEF activity, which was equivalent to a level of GSK-3 inhibition similar to that of cells treated with 20 mmol/l lithium or 500 nmol/l (2'Z,3'E)-6-bromoindirubin-3'-oxime. These results demonstrate the usefulness of low-voltage electrical pulses to enhance the uptake and bioactivity of TAT-conjugated molecules in different cell types. PMID:19107119

  20. Aldosterone Antagonists in Monotherapy Are Protective against Streptozotocin-Induced Diabetic Nephropathy in Rats

    PubMed Central

    Banki, Nora F.; Ver, Agota; Wagner, Laszlo J.; Vannay, Adam; Degrell, Peter; Prokai, Agnes; Gellai, Renata; Lenart, Lilla; Szakal, Dorottya-Nagy; Kenesei, Eva; Rosta, Klara; Reusz, Gyorgy; Szabo, Attila J.; Tulassay, Tivadar; Baylis, Chris; Fekete, Andrea

    2012-01-01

    Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) are the standard clinical therapy of diabetic nephropathy (DN), while aldosterone antagonists are only used as adjuncts. Previously in experimental DN we showed that Na/K ATPase (NKA) is mislocated and angiotensin II leads to superimposed renal progression. Here we investigated the monotherapeutic effect of aldosterone blockers on the progression of DN and renal NKA alteration in comparison to ACEi and ARBs. Streptozotocin-diabetic rats developing DN were treated with aldosterone antagonists; ACEi and ARB. Renal function, morphology, protein level and tubular localization of NKA were analyzed. To evaluate the effect of high glucose per se; HK-2 proximal tubular cells were cultured in normal or high concentration of glucose and treated with the same agents. Aldosterone antagonists were the most effective in ameliorating functional and structural kidney damage and they normalized diabetes induced bradycardia and weight loss. Aldosterone blockers also prevented hyperglycemia and diabetes induced increase in NKA protein level and enzyme mislocation. A monotherapy with aldosterone antagonists might be as, or more effective than ACEi or ARBs in the prevention of STZ-induced DN. Furthermore the alteration of the NKA could represent a novel pathophysiological feature of DN and might serve as an additional target of aldosterone blockers. PMID:22761931

  1. Aldosterone antagonists in monotherapy are protective against streptozotocin-induced diabetic nephropathy in rats.

    PubMed

    Banki, Nora F; Ver, Agota; Wagner, Laszlo J; Vannay, Adam; Degrell, Peter; Prokai, Agnes; Gellai, Renata; Lenart, Lilla; Szakal, Dorottya-Nagy; Kenesei, Eva; Rosta, Klara; Reusz, Gyorgy; Szabo, Attila J; Tulassay, Tivadar; Baylis, Chris; Fekete, Andrea

    2012-01-01

    Angiotensin converting enzyme inhibitors (ACEi) and angiotensin II receptor blockers (ARB) are the standard clinical therapy of diabetic nephropathy (DN), while aldosterone antagonists are only used as adjuncts. Previously in experimental DN we showed that Na/K ATPase (NKA) is mislocated and angiotensin II leads to superimposed renal progression. Here we investigated the monotherapeutic effect of aldosterone blockers on the progression of DN and renal NKA alteration in comparison to ACEi and ARBs. Streptozotocin-diabetic rats developing DN were treated with aldosterone antagonists; ACEi and ARB. Renal function, morphology, protein level and tubular localization of NKA were analyzed. To evaluate the effect of high glucose per se; HK-2 proximal tubular cells were cultured in normal or high concentration of glucose and treated with the same agents. Aldosterone antagonists were the most effective in ameliorating functional and structural kidney damage and they normalized diabetes induced bradycardia and weight loss. Aldosterone blockers also prevented hyperglycemia and diabetes induced increase in NKA protein level and enzyme mislocation. A monotherapy with aldosterone antagonists might be as, or more effective than ACEi or ARBs in the prevention of STZ-induced DN. Furthermore the alteration of the NKA could represent a novel pathophysiological feature of DN and might serve as an additional target of aldosterone blockers. PMID:22761931

  2. Aldosterone perturbs adiponectin and PAI-1 expression and secretion in 3T3-L1 adipocytes.

    PubMed

    Li, P; Zhang, X-N; Pan, C-M; Sun, F; Zhu, D-L; Song, H-D; Chen, M-D

    2011-06-01

    Aldosterone is considered as a new cardiovascular risk factor that plays an important role in metabolic syndrome; however, the underlying mechanism of these effects is not clear. Hypoadiponectinemia and elevated circulating concentration of plasminogen activator inhibitor-1 (PAI-1) are causally associated with obesity-related insulin resistance and cardiovascular disease. The aim of the present study is to investigate the effect of aldosterone on the production of adiponectin and PAI-1 in 3T3-L1 adipocytes. Northern and Western blot analyses revealed that aldosterone treatment inhibited adiponectin mRNA expression and secretion and simultaneously enhanced PAI-1 mRNA expression and secretion in a time- and dose-dependent manner. Rosiglitazone did not prevent aldosterone's effect on adiponectin or PAI-1 expression. In contrast, tumor necrosis factor (TNF)-α produced dramatic synergistic effects on adiponectin and PAI-1 expression when added together with aldosterone. Furthermore, the effects of aldosterone on adiponectin and PAI-1 expression appear to be mediated through glucocorticoid receptor (GR) but not mineralocorticoid receptor (MR). These results suggest that the effects of aldosterone on adiponectin and PAI-1 production are one of the underlying mechanisms linking it to insulin resistance, metabolic syndrome and cardiovascular disease. PMID:21667402

  3. Epidermal growth factor receptor signaling mediates aldosterone-induced profibrotic responses in kidney.

    PubMed

    Sheng, Lili; Yang, Min; Ding, Wei; Zhang, Minmin; Niu, Jianying; Qiao, Zhongdong; Gu, Yong

    2016-08-01

    Aldosterone has been recognized as a risk factor for the development of chronic kidney disease (CKD). Studies have indicated that enhanced activation of epidermal growth factor receptor (EGFR) is associated with the development and progression of renal fibrosis. But if EGFR is involved in aldosterone-induced renal fibrosis is less investigated. In the present study, we examined the effect of erlotinib, an inhibitor of EGFR tyrosine kinase activity, on the progression of aldosterone-induced renal profibrotic responses in a murine model underwent uninephrectomy. Erlotinib-treated rats exhibited relieved structural lesion comparing with rats treated with aldosterone alone, as characterized by glomerular hypertrophy, mesangial cell proliferation and expansion. Also, erlotinib inhibited the expression of TGF-β, α-SMA and mesangial matrix proteins such as collagen Ⅳ and fibronectin. In cultured mesangial cells, inhibition of EGFR also abrogated aldosterone-induced expression of extracellular matrix proteins, cell proliferation and migration. We also demonstrated that aldosterone induced the phosphorylation of EGFR through generation of ROS. And the activation of EGFR resulted in the phosphorylation of ERK1/2, leading to the activation of profibrotic pathways. Taken together, we concluded that aldosterone-mediated tissue fibrosis relies on ROS induced EGFR/ERK activation, highlighting EGFR as a potential therapeutic target for modulating renal fibrosis. PMID:27317889

  4. CESA TRAFFICKING INHIBITOR inhibits cellulose deposition and interferes with the trafficking of cellulose synthase complexes and their associated proteins KORRIGAN1 and POM2/CELLULOSE SYNTHASE INTERACTIVE PROTEIN1.

    PubMed

    Worden, Natasha; Wilkop, Thomas E; Esteve, Victor Esteva; Jeannotte, Richard; Lathe, Rahul; Vernhettes, Samantha; Weimer, Bart; Hicks, Glenn; Alonso, Jose; Labavitch, John; Persson, Staffan; Ehrhardt, David; Drakakaki, Georgia

    2015-02-01

    Cellulose synthase complexes (CSCs) at the plasma membrane (PM) are aligned with cortical microtubules (MTs) and direct the biosynthesis of cellulose. The mechanism of the interaction between CSCs and MTs, and the cellular determinants that control the delivery of CSCs at the PM, are not yet well understood. We identified a unique small molecule, CESA TRAFFICKING INHIBITOR (CESTRIN), which reduces cellulose content and alters the anisotropic growth of Arabidopsis (Arabidopsis thaliana) hypocotyls. We monitored the distribution and mobility of fluorescently labeled cellulose synthases (CESAs) in live Arabidopsis cells under chemical exposure to characterize their subcellular effects. CESTRIN reduces the velocity of PM CSCs and causes their accumulation in the cell cortex. The CSC-associated proteins KORRIGAN1 (KOR1) and POM2/CELLULOSE SYNTHASE INTERACTIVE PROTEIN1 (CSI1) were differentially affected by CESTRIN treatment, indicating different forms of association with the PM CSCs. KOR1 accumulated in bodies similar to CESA; however, POM2/CSI1 dissociated into the cytoplasm. In addition, MT stability was altered without direct inhibition of MT polymerization, suggesting a feedback mechanism caused by cellulose interference. The selectivity of CESTRIN was assessed using a variety of subcellular markers for which no morphological effect was observed. The association of CESAs with vesicles decorated by the trans-Golgi network-localized protein SYNTAXIN OF PLANTS61 (SYP61) was increased under CESTRIN treatment, implicating SYP61 compartments in CESA trafficking. The properties of CESTRIN compared with known CESA inhibitors afford unique avenues to study and understand the mechanism under which PM-associated CSCs are maintained and interact with MTs and to dissect their trafficking routes in etiolated hypocotyls. PMID:25535279

  5. CESA TRAFFICKING INHIBITOR Inhibits Cellulose Deposition and Interferes with the Trafficking of Cellulose Synthase Complexes and Their Associated Proteins KORRIGAN1 and POM2/CELLULOSE SYNTHASE INTERACTIVE PROTEIN11[OPEN

    PubMed Central

    Wilkop, Thomas E.; Esteve, Victor Esteva; Jeannotte, Richard; Lathe, Rahul; Vernhettes, Samantha; Weimer, Bart; Hicks, Glenn; Alonso, Jose; Labavitch, John; Persson, Staffan; Ehrhardt, David; Drakakaki, Georgia

    2015-01-01

    Cellulose synthase complexes (CSCs) at the plasma membrane (PM) are aligned with cortical microtubules (MTs) and direct the biosynthesis of cellulose. The mechanism of the interaction between CSCs and MTs, and the cellular determinants that control the delivery of CSCs at the PM, are not yet well understood. We identified a unique small molecule, CESA TRAFFICKING INHIBITOR (CESTRIN), which reduces cellulose content and alters the anisotropic growth of Arabidopsis (Arabidopsis thaliana) hypocotyls. We monitored the distribution and mobility of fluorescently labeled cellulose synthases (CESAs) in live Arabidopsis cells under chemical exposure to characterize their subcellular effects. CESTRIN reduces the velocity of PM CSCs and causes their accumulation in the cell cortex. The CSC-associated proteins KORRIGAN1 (KOR1) and POM2/CELLULOSE SYNTHASE INTERACTIVE PROTEIN1 (CSI1) were differentially affected by CESTRIN treatment, indicating different forms of association with the PM CSCs. KOR1 accumulated in bodies similar to CESA; however, POM2/CSI1 dissociated into the cytoplasm. In addition, MT stability was altered without direct inhibition of MT polymerization, suggesting a feedback mechanism caused by cellulose interference. The selectivity of CESTRIN was assessed using a variety of subcellular markers for which no morphological effect was observed. The association of CESAs with vesicles decorated by the trans-Golgi network-localized protein SYNTAXIN OF PLANTS61 (SYP61) was increased under CESTRIN treatment, implicating SYP61 compartments in CESA trafficking. The properties of CESTRIN compared with known CESA inhibitors afford unique avenues to study and understand the mechanism under which PM-associated CSCs are maintained and interact with MTs and to dissect their trafficking routes in etiolated hypocotyls. PMID:25535279

  6. Adipocytes, aldosterone and obesity-related hypertension.

    PubMed

    Dinh Cat, Aurelie Nguyen; Friederich-Persson, Malou; White, Anna; Touyz, Rhian M

    2016-07-01

    Understanding the mechanisms linking obesity with hypertension is important in the current obesity epidemic as it may improve therapeutic interventions. Plasma aldosterone levels are positively correlated with body mass index and weight loss in obese patients is reported to be accompanied by decreased aldosterone levels. This suggests a relationship between adipose tissue and the production/secretion of aldosterone. Aldosterone is synthesized principally by the adrenal glands, but its production may be regulated by many factors, including factors secreted by adipocytes. In addition, studies have reported local synthesis of aldosterone in extra-adrenal tissues, including adipose tissue. Experimental studies have highlighted a role for adipocyte-secreted aldosterone in the pathogenesis of obesity-related cardiovascular complications via the mineralocorticoid receptor. This review focuses on how aldosterone secretion may be influenced by adipose tissue and the importance of these mechanisms in the context of obesity-related hypertension. PMID:27357931

  7. Use of bacterial surrogates as a tool to explore antimalarial drug interaction: Synergism between inhibitors of malarial dihydrofolate reductase and dihydropteroate synthase.

    PubMed

    Talawanich, Yuwadee; Kamchonwongpaisan, Sumalee; Sirawaraporn, Worachart; Yuthavong, Yongyuth

    2015-09-01

    Interaction between antimalarial drugs is important in determining the outcome of chemotherapy using drug combinations. Inhibitors of dihydrofolate reductase (DHFR) such as pyrimethamine and of dihydropteroate synthase (DHPS) such as sulfa drugs are known to have synergistic interactions. However, studies of the synergism are complicated by the fact that the malaria parasite can also salvage exogenous folates, and the salvage may also be affected by the drugs. It is desirable to have a convenient system to study interaction of DHFR and DHPS inhibitors without such complications. Here, we describe the use of Escherichia coli transformed with malarial DHFR and DHPS, while its own corresponding genes have been inactivated by optimal concentration of trimethoprim and genetic knockout, respectively, to study the interaction of the inhibitors. Marked synergistic effects are observed for all combinations of pyrimethamine and sulfa inhibitors in the presence of trimethoprim. At 0.05μM trimethoprim, sum of fractional inhibitory concentrations, ΣFIC of pyrimethamine with sulfadoxine, pyrimethamine with sulfathiazole, pyrimethamine with sulfamethoxazole, and pyrimethamine with dapsone are in the range of 0.24-0.41. These results show synergism between inhibitors of the two enzymes even in the absence of folate transport and uptake. This bacterial surrogate system should be useful as a tool for assessing the interactions of drug combinations between the DHFR and DHPS inhibitors. PMID:25997881

  8. Recent Developments in Primary Aldosteronism.

    PubMed

    Asbach, E; Williams, T A; Reincke, M

    2016-06-01

    Primary aldosteronism (PA) is the most frequent endocrine cause of secondary arterial hypertension. Sporadic forms of PA caused mainly by an aldosterone producing adenoma (APA) or idiopathic adrenal hyperplasia (IAH) predominate; in contrast, familial forms (familial hyperaldosteronism types I, II and III) affect only a minor proportion of PA patients. Patient based registries and biobanks, international networks and next generation sequencing technologies have emerged over recent years. Somatic hot-spot mutations in the potassium channel GIRK4 (encoded by KCNJ5), in ATPases and a L-type voltage-gated calcium-channel correlate with the autonomous aldosterone production in approximately half of all APAs. The recently discovered form FH III is caused by different germline KCNJ5 mutations with variable clinical presentations and severity. Autoantibodies to the angiotensin II Type 1 receptor have been identified in patients with PA and possibly play a pathophysiological role in the development of PA. Adrenal vein sampling (AVS) represents the gold standard in differentiating unilateral and bilateral forms of PA. Recent consensus papers have tried to implement current guidelines in order to standardise the technique of AVS. New techniques like segmental AVS might allow a finer mapping of the aldosterone production within the adrenal gland. The measurement of the steroids 18-hydroxycortisol and 18-oxocortisol by liquid chromatography tandem mass spectrometry has been shown to be useful to distinguish between unilateral and bilateral forms of PA. PMID:27219889

  9. New EPSP synthase inhibitors: synthesis and evaluation of an aromatic tetrahedral intermediate mimic containing a 3-malonate ether as a 3-phosphate surrogate.

    PubMed

    Miller, M J; Cleary, D G; Ream, J E; Snyder, K R; Sikorski, J A

    1995-12-01

    A new analog of the EPSP synthase enzyme reaction intermediate 1, containing a 3-malonate ether moiety in place of the usual 3-phosphate group, was synthesized from 3,5-dihydroxybenzoic acid. This simple, synthetically accessible aromatic compound (5) is an effective competitive inhibitor versus S3P with an apparent Ki of 1.3 +/- 0.22 microM. This result demonstrates that a simple benzene ring can be a suitable achiral substitute for the more complex shikimate ring in the design of EPSP synthase inhibitors. Furthermore, the greater potency of 5 versus the phenol 6, glycolate 7 and the gallic acid analog 8 demonstrates the requirement for multiple anionic charges at the dihydroxybenzoate 5-position in order to attain effective inhibition of this enzyme. However, this 3-malonate ether substituted compound was at least 10-fold less effective as a bisubstrate inhibitor than the corresponding 3-phosphate. This suggests that tetrahedral intermediate mimics possessing a 3-malonate ether moiety are less effective than their corresponding 3-phosphates in accessing the optimal enzyme conformation stabilizing 1. PMID:8770393

  10. S-2-amino-5-(2-nitroimidazol-1-yl)pentanoic acid: a model for potential bioreductively activated prodrugs for inhibitors of nitric oxide synthase (NOS) activity.

    PubMed

    Ulhaq, S; Naylor, M A; Chinje, E C; Threadgill, M D; Stratford, I J

    1997-01-01

    Treatment of 1,1-dimethylethyl S-(2-1,1-dimethylethoxycarbonylamino)-5-bromopentanoate with 1-potassio-2-nitroimidazole, followed by deprotection, afforded S-2-amino-5-(2-nitroimidazol-1-yl)pentanoic acid, which was reduced to S-2-amino-5-(2-aminoimidazol-1-yl)pentanoic acid. This aminoimadazole inhibited rat brain nitric oxide synthase (NOS) activity 3.2 times more potently than did the nitro analogue. Thus S-2-amino-5-(2-nitroimidazol-1-yl)pentanoic acid is a potent prodrug which may be bioreductively activated to a NOS inhibitor in hypoxic solid tumours. PMID:9051114

  11. An NMR Biochemical Assay for Fragment-Based Drug Discovery: Evaluation of an Inhibitor Activity on Spermidine Synthase of Trypanosoma cruzi.

    PubMed

    Yamasaki, Kazuhiko; Tani, Osamu; Tateishi, Yukihiro; Tanabe, Eiki; Namatame, Ichiji; Niimi, Tatsuya; Furukawa, Koji; Sakashita, Hitoshi

    2016-03-10

    Although NMR in fragment-based drug discovery is utilized almost exclusively to evaluate physical binding between molecules, it should be also a powerful tool for biochemical assay, evaluating inhibitory effect of compounds on enzymatic activity. Time-dependent spectral change in real-time monitoring or inhibitor concentration-dependent spectral change after constant-time reaction was processed by factor analysis, by which reaction rate or IC50 value was obtained. Applications to spermidine synthase of Trypanosoma cruzi, which causes Chagas disease, are described. PMID:26881725

  12. Putative anxiety-linked effects of the nitric oxide synthase inhibitor L-NAME in three murine exploratory behavior models.

    PubMed

    Czech, Donald A; Jacobson, Erika B; LeSueur-Reed, Kolitta T; Kazel, Melanie R

    2003-07-01

    The aim of the current study was to extend investigation into possible linkage between nitric oxide (NO) and anxiety-linked behavior using a battery of tests. Effects of the NO synthase (NOS) inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) were investigated in three murine models of anxiety-the light-dark, hole-board and elevated plus-maze-in between-groups designs. Treatment groups included L-NAME (0 [vehicle, or Veh], 10, 25, and 50 mg/kg) and 50 mg/kg of the inactive isomer N(G)-nitro-D-arginine methyl ester (D-NAME) injected subcutaneously. Mice exhibited a robust anxiogenic-like response profile reflected by dose-related decreases in both light-dark (transitions and time in lighted area) and hole-board (head dips and time spent head dipping) test measures, reaching statistical significance at 25 and 50 mg/kg L-NAME when compared to Veh controls (P<.05 or.01; Dunnett's t test), while distance traveled and rearing showed no significant differential pattern in either model. In both models, there was a strong dissociation between nonspecific locomotion and putative exploratory behaviors. D-NAME was not significantly different from Veh condition in either model, indicating a stereospecific action and supporting NO involvement. A dose-related decrease was also observed for several traditional and ethological measures in the plus-maze; however, the effect was limited and relatively weak or absent; with the exception of open-arm and percent open-arm entries, putative anxiety-sensitive measures reached statistical significance only at the highest dose. Reductions in motor activity compromised ability to dissociate an anxiety linkage from a nonspecific motor effect in most measures. It is concluded that the hole-board and light-dark tests provide indication of anxiogenic-like action of NOS inhibition, suggesting that NO has an anxiolytic action. Data from the plus-maze are unclear, owing to a confounding motor influence in most measures. PMID:12957214

  13. Role of Nox2 and p22phox in Persistent Postoperative Hypertension in Aldosterone-Producing Adenoma Patients after Adrenalectomy

    PubMed Central

    Geng, Xiaojing; Yan, Li; Dong, Jun; Liang, Ying; Deng, Yajuan; Li, Ting; Luo, Tongfeng; Lin, Hailun; Zhang, Shaoling

    2016-01-01

    Adrenal aldosterone-producing adenoma (APA), producing the salt-retaining hormone aldosterone, commonly causes secondary hypertension, which often persists after unilateral adrenalectomy. Although persistent hypertension was correlated with residual hormone aldosterone, the in vivo mechanism remains unclear. NADPH oxidase is the critical cause of aldosterone synthesis in vitro. Nox2 and p22phox comprise the NADPH oxidase catalytic core, serving to initiate a reactive oxygen species (ROS) cascade that may participate in the pathology. mRNAs of seven NADPH oxidase isoforms in APA were evaluated by RT-PCR and Q-PCR and their proteins by immunohistochemistry and Western blotting. NADPH oxidase activity was also detected. Nox2 and p22phox were especially abundant in APA. Particularly higher Nox2 and p22phox gene and protein levels were seen in APA than controls. Significant correlations between Nox2 mRNA and aldosterone synthase (CYP11B2) mRNA (R = 0.66, P < 0.01) and Nox2 protein and baseline plasma aldosterone concentration (PAC) (R = 0.503, P < 0.01) were detected in APA; however, none were found between p22phox mRNA, CYP11B2 mRNA, p22phox protein, and baseline PAC. Importantly, we found that Nox2 localized specifically in hyperplastic zona glomerulosa cells. In conclusion, our results highlight that Nox2 and p22phox may be directly involved in pathological aldosterone production and zona glomerulosa cell proliferation after APA resection. PMID:27057164

  14. Blood pressure in patients with primary aldosteronism is influenced by bradykinin B(2) receptor and alpha-adducin gene polymorphisms.

    PubMed

    Mulatero, Paolo; Williams, Tracy A; Milan, Alberto; Paglieri, Cristina; Rabbia, Franco; Fallo, Francesco; Veglio, Franco

    2002-07-01

    Primary aldosteronism (PA) is the most common cause of endocrine hypertension. PA is most frequently presented as moderate to severe hypertension, but the clinical and biochemical features vary widely. The aim of our study was to identify genetic variants that influence the phenotype of patients with PA. We hypothesized that genetic variants potentially affecting aldosterone production (aldosterone synthase, CYP11B2), renal proximal tubule reabsorption (alpha-adducin), or the mechanisms of counterbalance leading to vasodilatation and sodium excretion (bradykinin B(2)-receptor, B(2)R) could influence the clinical and biochemical characteristics of patients with PA. We studied three polymorphisms of these genes (C-344T of CYP11B2, G460W of alpha-adducin, and C-58T of B(2)R) in 167 primary aldosteronism patients (56 with aldosterone-producing adenoma and 111 with idiopathic hyperaldosteronism). B(2)R and alpha-adducin genotypes were strong independent predictors of both systolic and diastolic blood pressure levels; plasma renin activity and aldosterone also play a marginal role on BP levels. Body mass index, age, sex, and CYP11B2 genotype displayed no significant effect on the clinical parameters of our population. In particular, alpha-adducin and B(2)R polymorphisms accounted for 13.2% and 11.0% of the systolic and diastolic blood pressure variance, respectively. These data suggest that genetic variants of alpha-adducin and the bradykinin B(2)-R influence the blood pressure levels in patients with primary aldosteronism. PMID:12107246

  15. [Aldosterone/renin ratio in the diagnosis of primary aldosteronism].

    PubMed

    Ríos, María Carolina; Izquierdo, Anahí; Sotelo, Mercedes; Honnorat, Egle; Rodríguez Cuimbra, Silvia; Catay, Erika; Popescu, Bogdan M

    2011-01-01

    Primary aldosteronism (PA) is a possible cause of endocrine hypertension. Recent studies have suggested a prevalence ranging between 5% and 15% of all hypertensive patients, and 20% in patients with refractory hypertension.The objective of this transversal study was to establish the prevalence of PA in a hypertensive population using the aldosterone / plasma renin ratio (ARR) as a screening method, considering that the prevalence rates for PA among hypertensive people present a wide range and that there are only few reports in Argentina. This ratio was then related with the degree of hypertension and with the presence or absence of hypokalemia. Serum aldosterone and plasma renin activity levels were measured in 123 hypertensive patients after discontinuing all medications that could interfere with the hormonal tests. Patients with an aldosterone/plasma renin activity ratio > 25 were submitted to the saline suppression test (SST) to confirm the diagnosis of PA, followed by computed tomography (CT) of the abdomen. Twenty patients presented an ARR > 25 (16.4%). Eighteen were submitted to the SST, eight had a diagnosis of PA confirmed with positive SST (6.5%). Of 8 patients who underwent an abdominal CT, two showed adenoma, and six normal adrenal anatomy. All the eight patients with a PA diagnosis belonged to group II and III of hypertension according to Joint National Committee VI (JNC VI), and only 4 (50%) were normokalemic. We found a 6.5% prevalence of PA, associated with grade II and III hypertension, and normal potassium values in half of the patients with PA. PMID:22167725

  16. High risk of adrenal toxicity of N1-desoxy quinoxaline 1,4-dioxide derivatives and the protection of oligomeric proanthocyanidins (OPC) in the inhibition of the expression of aldosterone synthetase in H295R cells.

    PubMed

    Wang, Xu; Yang, Chunhui; Ihsan, Awais; Luo, Xun; Guo, Pu; Cheng, Guyue; Dai, Menghong; Chen, Dongmei; Liu, Zhenli; Yuan, Zonghui

    2016-02-01

    Quinoxaline 1,4-dioxide derivatives (QdNOs) with a wide range of biological activities are used in animal husbandry worldwide. It was found that QdNOs significantly inhibited the gene expression of CYP11B1 and CYP11B2, the key aldosterone synthases, and thus reduced aldosterone levels. However, whether the metabolites of QdNOs have potential adrenal toxicity and the role of oxidative stress in the adrenal toxicity of QdNOs remains unclear. The relatively new QdNOs, cyadox (CYA), mequindox (MEQ), quinocetone (QCT) and their metabolites, were selected for elucidation of their toxic mechanisms in H295R cells. Interestingly, the results showed that the main toxic metabolites of QCT, MEQ, and CYA were their N1-desoxy metabolites, which were more harmful than other metabolites and evoked dose and time-dependent cell damage on adrenal cells and inhibited aldosterone production. Gene and protein expression of CYP11B1 and CYP11B2 and mRNA expression of transcription factors, such as NURR1, NGFIB, CREB, SF-1, and ATF-1, were down regulated by N1-desoxy QdNOs. The natural inhibitors of oxidant stress, oligomeric proanthocyanidins (OPC), could upregulate the expression of diverse transcription factors, including CYP11B1 and CYP11B2, and elevated aldosterone levels to reduce adrenal toxicity. This study demonstrated for the first time that N1-desoxy QdNOs have the potential to be the major toxic metabolites in adrenal toxicity, which may shed new light on the adrenal toxicity of these fascinating compounds and help to provide a basic foundation for the formulation of safety controls for animal products and the design of new QdNOs with less harmful effects. PMID:26802905

  17. Inhibition of invasion by glycogen synthase kinase-3 beta inhibitors through dysregulation of actin re-organisation via down-regulation of WAVE2.

    PubMed

    Yoshino, Yuki; Suzuki, Manami; Takahashi, Hidekazu; Ishioka, Chikashi

    2015-08-14

    Cancer cell invasion is a critical phenomenon in cancer pathogenesis. Glycogen synthase kinase-3β (GSK-3β) has been reported to regulate cancer cell invasion both negatively and positively. Thus, the net effect of GSK-3β on invasion is unclear. In this report, we showed that GSK-3β inhibitors induced dysregulation of the actin cytoskeleton and functional insufficiency of focal adhesion, which resulted in suppressed invasion. In addition, WAVE2, an essential molecule for actin fibre branching, was down-regulated after GSK-3β inhibition. Collectively, we propose that the WAVE2-actin cytoskeleton axis is an important target of GSK-3β inhibitors in cancer cell invasion. PMID:26116771

  18. The sulfonylurea herbicide sulfometuron methyl is an extremely potent and selective inhibitor of acetolactate synthase in Salmonella typhimurium.

    PubMed

    LaRossa, R A; Schloss, J V

    1984-07-25

    The sulfonylurea herbicide sulfometuron methyl inhibits the growth of several bacterial species. In the presence of L-valine, sulfometuron methyl inhibits Salmonella typhimurium, this inhibition can be reversed by L-isoleucine. Reversal of growth retardation by L-isoleucine, accumulation of guanosine 5'-diphosphate 3'-diphosphate (magic spot), and relA mutant hypersensitivity suggest sulfometuron methyl interference with branched-chain amino acid biosynthesis. Growth inhibition of S. typhimurium is mediated by sulfometuron methyl's inhibition of acetolactate synthase, the first common enzyme in the branched-chain amino acid biosynthetic pathway. Sulfometuron methyl exhibits slow-binding inhibition of acetolactate synthase isozyme II from S. typhimurium with an initial Ki of 660 +/- 60 nM and a final, steady-state Ki of 65 +/- 25 nM. Inhibition of acetolactate synthase by sulfometuron methyl is substantially more rapid (10 times) in the presence of pyruvate with a maximal first-order rate constant for conversion from initial to final steady-state inhibition of 0.25 +/- 0.07 min-1 (minimal half-time of 2.8 min). Mutants of S. typhimurium able to grow in the presence of sulfometuron methyl were obtained. They have acetolactate synthase activity that is insensitive to sulfometuron methyl because of mutations in or near ilvG, the structural gene for acetolactate synthase isozyme II. PMID:6378902

  19. Microalbuminuria and hypertension in pregnancy: role of aldosterone and inflammation.

    PubMed

    Armanini, Decio; Ambrosini, Guido; Sabbadin, Chiara; Donà, Gabriella; Clari, Giulio; Bordin, Luciana

    2013-09-01

    Women with a history of hypertension in pregnancy are at increased risk of microalbuminuria later in life. Microalbuminuria is a marker of kidney dysfunction frequently related to an inflammatory event. Pregnancy is a dynamic process characterized by immune tolerance, angiogenesis, and hormonal regulation. Menstruation and pregnancy are associated with a physiological inflammation, which is altered in preeclampsia and probably in other hypertensive situations of pregnancy. An imbalance between pro-oxidant factors and the ability to scavenge these factors produces oxidative stress, which has been evaluated in many cells, but leukocytes are the main source of inflammatory cytokines and experimental and clinical evidence support a possible role of aldosterone as a mediator of placental and renal damage mediated by growth factors, reactive oxygen species, and cytokines. Angiotensin-converting enzyme inhibitors and aldosterone receptor blockers are frequently effective in reducing the risk of progression of cardiovascular and renal disease. PMID:24034651

  20. Tools for discovery of inhibitors of the 1-deoxy-D-xylulose 5-phosphate (DXP) synthase and DXP reductoisomerase: an approach with enzymes from the pathogenic bacterium Pseudomonas aeruginosa.

    PubMed

    Altincicek, B; Hintz, M; Sanderbrand, S; Wiesner, J; Beck, E; Jomaa, H

    2000-09-15

    Two Pseudomonas aeruginosa genes encoding the enzymes 1-deoxy-D-xylulose 5-phosphate (DXP) synthase and DXP reductoisomerase, both involved in the mevalonate-independent biosynthesis of isoprenoids, have been expressed as recombinant enzymes in Escherichia coli. The purified P. aeruginosa DXP reductoisomerase was inhibited by submicromolar concentrations of the antibiotics fosmidomycin and FR-900098 in a well established method. A novel and convenient spectrophotometric assay was developed to determine activity and inhibition of P. aeruginosa DXP synthase. Fluoropyruvate is described as a first inhibitor of DXP synthase. PMID:11034300

  1. Characterization of Transporters in the Hepatic Uptake of TAK-475 M-I, a Squalene Synthase Inhibitor, in Rats and Humans.

    PubMed

    Ebihara, T; Takeuchi, T; Moriya, Y; Tagawa, Y; Kondo, T; Moriwaki, T; Asahi, S

    2016-06-01

    TAK-475 (lapaquistat acetate) is a squalene synthase inhibitor and M-I is a pharmacologically active metabolite of TAK-475. Preclinical pharmacokinetic studies have demonstrated that most of the dosed TAK-475 was hydrolyzed to M-I during the absorption process and the concentrations of M-I in the liver, the main organ of cholesterol biosynthesis, were much higher than those in the plasma after oral administration to rats. In the present study, the mechanism of the hepatic uptake of M-I was investigated.The uptake studies of (14)C-labeled M-I into rat and human hepatocytes indicated that the uptakes of M-I were concentrative, temperature-dependent and saturable in both species with Km values of 4.7 and 2.8 μmol/L, respectively. M-I uptake was also inhibited by cyclosporin A, an inhibitor for hepatic uptake transporters including organic anion transporting polypeptide (OATP). In the human hepatocytes, M-I uptake was hardly inhibited by estrone 3-sulfate as an inhibitor for OATP1B1, and most of the M-I uptake was Na(+)-independent. Uptake studies using human transporter-expressing cells revealed the saturable uptake of M-I for OATP1B3 with a Km of 2.13 μmol/L. No obvious uptake of M-I was observed in the OATP1B1-expressing cells.These results indicated that M-I was taken up into hepatocytes via transporters in both rats and humans. OATP1B3 would be mainly involved in the hepatic uptake of M-I in humans. These findings suggested that hepatic uptake transporters might contribute to the liver-selective inhibition of cholesterol synthesis by TAK-475. This is the first to clarify a carrier-mediated hepatic uptake mechanism for squalene synthase inhibitors. PMID:27011383

  2. Anti-Inflammatory Effects of Specific Cyclooxygenase 2,5-Lipoxygenase, and Inducible Nitric Oxide Synthase Inhibitors on Experimental Autoimmune Anterior Uveitis (EAAU)

    PubMed Central

    Bora, Nalini S.; Sohn, Jeong-Hyeon; Bora, Puran S.; Kaplan, Henry J.; Kulkarni, Prasad

    2007-01-01

    Purpose Inflammation, in general, causes the release of a variety of inflammatory mediators that in turn induce cyclooxygenase (COX) 2, nitric oxide synthase (iNOS) and 5-lipoxygense (LP) synthesis, producing large amounts of inflammatory prostaglandins (PG), nitric oxide (NO), and leukotriene (LT) B4. Therefore, inhibition of these enzymes may abrogate intraocular inflammation in experimental autoimmune anterior uveitis (EAAU). Methods Lewis rats were immunized with melanin-associated antigen (MAA) isolated from bovine iris and ciliary body. These animals were divided into three groups. The first group of rats received subcutaneous injection of COX 2 inhibitor CS 236 at different time points. The second and third groups of animals received subcutaneous aminoguanidine (AG), an iNOS inhibitor, and nordihydroguaiaretic acid (NDGA), a 5-LP inhibitor, respectively. Control animals received vehicle. Rat eyes were examined daily by slit-lamp biomicroscopy from Day 7 to 30 post injection for uveitis. Animals were also sacrificed at various time points for histologic analysis. Results Control animals developed severe EAAU in both eyes. The disease started in these animals on Day 12 post immunization and lasted for ten days. Interestingly, CS 236, a potent COX 2 inhibitor, completely abrogated EAAU when the animals were treated daily from the Day 0 to 14 or Day 0 to 20 after MAA injection. Furthermore, daily CS 236 treatment after the onset of EAAU (Day 14–20) significantly reduced the severity (both clinical and histologic) of EAAU and shortened the duration of disease. iNOS inhibitor (AG) and 5-LP inhibitor (NDGA) partially attenuated EAAU. Conclusions Our results show that EAAU was partially attenuated by AG and NDGA. Interestingly, CS 236, a potent COX 2 inhibitor, completely inhibited EAAU in male Lewis rats most likely by inhibiting the initial phase and onset of the disease. PMID:16019677

  3. The role of urinary aldosterone for the diagnosis of primary aldosteronism.

    PubMed

    Ceral, J; Malirova, E; Ballon, M; Solar, M

    2014-08-01

    When diagnosing primary aldosteronism, the measurement of urinary aldosterone after oral sodium loading is one of the currently recommended confirmatory tests. The aim of the study was to assess the repeatability and interpretation of urinary aldosterone in patients examined for suspected primary aldosteronism. Sixty-four hypertensive patients with suspected primary aldosteronism were prospectively enrolled and examined according to the study protocol. After antihypertensive medications interfering with renin-angiotensin-aldosterone system were withdrawn for at least 2 weeks, the confirmatory testing was performed: oral sodium loading preceded the collection of 24-h urine sample and subsequent saline infusion test. The identical procedures were repeated after 2 weeks. The concordant results of both saline infusion tests served for confirmation/exclusion of primary aldosteronism. Forty-nine patients were included in data analysis. Primary aldosteronism was excluded in 16, and confirmed in 33 individuals. The repeatability of urinary aldosterone was evaluated in 44 patients: the difference of urinary aldosterone levels ranged between 1 and 88% (median 31%). Ninety-three urine samples from 49 patients were used to validate the interpretation of urinary aldosterone in respect to the diagnosis of primary aldosteronism made by saline infusion testing; 96% sensitivity was characterized by urinary aldosterone ≥19 nmol/day, and 96% specificity was associated with urinary aldosterone ≥92 nmol/day. In 22 (45%) patients, urinary aldosterone remained in the "gray" zone between 19 and 92 nmol/day in all provided samples. The estimation of urinary aldosterone excretion after oral sodium loading is associated with marked intraindividual variability, and significant number of inconclusive results. PMID:24810470

  4. Sensitivity of Aspergillus nidulans to the Cellulose Synthase Inhibitor Dichlobenil: Insights from Wall-Related Genes’ Expression and Ultrastructural Hyphal Morphologies

    PubMed Central

    Obersriebnig, Michael; Salerno, Marco; Pum, Dietmar; Strauss, Joseph

    2013-01-01

    The fungal cell wall constitutes an important target for the development of antifungal drugs, because of its central role in morphogenesis, development and determination of fungal-specific molecular features. Fungal walls are characterized by a network of interconnected glycoproteins and polysaccharides, namely α-, β-glucans and chitin. Cell walls promptly and dynamically respond to environmental stimuli by a signaling mechanism, which triggers, among other responses, modulations in wall biosynthetic genes’ expression. Despite the absence of cellulose in the wall of the model filamentous fungus Aspergillus nidulans, we found in this study that fungal growth, spore germination and morphology are affected by the addition of the cellulose synthase inhibitor dichlobenil. Expression analysis of selected genes putatively involved in cell wall biosynthesis, carried out at different time points of drug exposure (i.e. 0, 1, 3, 6 and 24 h), revealed increased expression for the putative mixed linkage β-1,3;1,4 glucan synthase celA together with the β-1,3-glucan synthase fksA and the Rho-related GTPase rhoA. We also compared these data with the response to Congo Red, a known plant/fungal drug affecting both chitin and cellulose biosynthesis. The two drugs exerted different effects at the cell wall level, as shown by gene expression analysis and the ultrastructural features observed through atomic force microscopy and scanning electron microscopy. Although the concentration of dichlobenil required to affect growth of A. nidulans is approximately 10-fold higher than that required to inhibit plant cellulose biosynthesis, our work for the first time demonstrates that a cellulose biosynthesis inhibitor affects fungal growth, changes fungal morphology and expression of genes connected to fungal cell wall biosynthesis. PMID:24312197

  5. Sensitivity of Aspergillus nidulans to the cellulose synthase inhibitor dichlobenil: insights from wall-related genes' expression and ultrastructural hyphal morphologies.

    PubMed

    Guerriero, Gea; Silvestrini, Lucia; Obersriebnig, Michael; Salerno, Marco; Pum, Dietmar; Strauss, Joseph

    2013-01-01

    The fungal cell wall constitutes an important target for the development of antifungal drugs, because of its central role in morphogenesis, development and determination of fungal-specific molecular features. Fungal walls are characterized by a network of interconnected glycoproteins and polysaccharides, namely α-, β-glucans and chitin. Cell walls promptly and dynamically respond to environmental stimuli by a signaling mechanism, which triggers, among other responses, modulations in wall biosynthetic genes' expression. Despite the absence of cellulose in the wall of the model filamentous fungus Aspergillus nidulans, we found in this study that fungal growth, spore germination and morphology are affected by the addition of the cellulose synthase inhibitor dichlobenil. Expression analysis of selected genes putatively involved in cell wall biosynthesis, carried out at different time points of drug exposure (i.e. 0, 1, 3, 6 and 24 h), revealed increased expression for the putative mixed linkage β-1,3;1,4 glucan synthase celA together with the β-1,3-glucan synthase fksA and the Rho-related GTPase rhoA. We also compared these data with the response to Congo Red, a known plant/fungal drug affecting both chitin and cellulose biosynthesis. The two drugs exerted different effects at the cell wall level, as shown by gene expression analysis and the ultrastructural features observed through atomic force microscopy and scanning electron microscopy. Although the concentration of dichlobenil required to affect growth of A. nidulans is approximately 10-fold higher than that required to inhibit plant cellulose biosynthesis, our work for the first time demonstrates that a cellulose biosynthesis inhibitor affects fungal growth, changes fungal morphology and expression of genes connected to fungal cell wall biosynthesis. PMID:24312197

  6. Role of calcium in effects of atrial natriuretic peptide on aldosterone production in adrenal glomerulosa cells

    SciTech Connect

    Chartier, L.; Schiffrin, E.L.

    1987-04-01

    Atrial natriuretic peptide (ANP) inhibits the stimulation of aldosterone secretion by isolated adrenal glomerulosa cells produced by angiotensin II (ANG II), ACTH, and potassium. The effect of ANP on the dose-response curve of aldosterone stimulated by ANG II, ACTH, and potassium on isolated rat adrenal glomerulosa cells was studied. In the presence of ANP the maximal response of aldosterone output stimulated by ANG II or potassium decreased and the half-maximum (EC/sub 50/) of the response to ACTH was displaced to the right. Because these effects resemble those of calcium-channel blockers, the authors investigated the effect of different concentrations of nifedipine, a dihydropyridine calcium-channel blocker, on the dose-response curve of aldosterone stimulated by ANG II, ACTH, and potassium. Nifedipine produced effects similar to ANP. The maximal response of aldosterone stimulated by ANG II and potassium was decreased and the dose-response curve to ACTH was displaced to the right. ANP decreased the maximal response of aldosterone to the dihydropyridine derivative BAY K8644, a calcium-channel activator, without change in its EC/sub 50/. In contrast, nifedipine displaced the dose-response curve to BAY K8644 to the right as expected of a competitive inhibitor. The effect of ANP and nifedipine on basal and stimulated /sup 45/Ca influx into isolated rat adrenal glomerulosa cells was studied. ANP may act on the rat adrenal glomerulosa cells at least in part by interference with calcium entry.

  7. VLDL-activated cell signaling pathways that stimulate adrenal cell aldosterone production.

    PubMed

    Tsai, Ying-Ying; Rainey, William E; Johnson, Maribeth H; Bollag, Wendy B

    2016-09-15

    Aldosterone plays an important role in regulating ion and fluid homeostasis and thus blood pressure, and hyperaldosteronism results in hypertension. Hypertension is also observed with obesity, which is associated with additional health risks, including cardiovascular disease. Obese individuals have high serum levels of very low-density lipoprotein (VLDL), which has been shown to stimulate aldosterone production; however, the mechanisms underlying VLDL-induced aldosterone production are still unclear. Here we demonstrate in human adrenocortical carcinoma (HAC15) cells that submaximal concentrations of angiotensin II and VLDL stimulate aldosterone production in an additive fashion, suggesting the possibility of common mechanisms of action. We show using inhibitors that VLDL-induced aldosterone production is mediated by the PLC/IP3/PKC signaling pathway. Our results suggest that PKC is upstream of the extracellular signal-regulated kinase (ERK) activation previously observed with VLDL. An understanding of the mechanisms mediating VLDL-induced aldosterone production may provide insights into therapies to treat obesity-associated hypertension. PMID:27222295

  8. Differential Expression of 1-Aminocyclopropane-1-Carboxylate Synthase Genes during Orchid Flower Senescence Induced by the Protein Phosphatase Inhibitor Okadaic Acid1

    PubMed Central

    Wang, Ning Ning; Yang, Shang Fa; Charng, Yee-yung

    2001-01-01

    Applying 10 pmol of okadaic acid (OA), a specific inhibitor of type 1 or type 2A serine/threonine protein phosphatases, to the orchid (Phalaenopsis species) stigma induced a dramatic increase in ethylene production and an accelerated senescence of the whole flower. Aminoethoxyvinylglycine or silver thiosulfate, inhibitors of ethylene biosynthesis or action, respectively, effectively inhibited the OA-induced ethylene production and retarded flower senescence, suggesting that the protein phosphatase inhibitor induced orchid flower senescence through an ethylene-mediated signaling pathway. OA treatment induced a differential expression pattern for the 1-aminocyclopropane-1-carboxylic acid synthase multigene family. Accumulation of Phal-ACS1 transcript in the stigma, labelum, and ovary induced by OA were higher than those induced by pollination as determined by “semiquantitative” reverse transcriptase-polymerase chain reaction. In contrast, the transcript levels of Phal-ACS2 and Phal-ACS3 induced by OA were much lower than those induced by pollination. Staurosporine, a protein kinase inhibitor, on the other hand, inhibited the OA-induced Phal-ACS1 expression in the stigma and delayed flower senescence. Our results suggest that a hyper-phosphorylation status of an unidentified protein(s) is involved in up-regulating the expression of Phal-ACS1 gene resulting in increased ethylene production and accelerated the senescence process of orchid flower. PMID:11351088

  9. An Innovative Strategy for Dual Inhibitor Design and Its Application in Dual Inhibition of Human Thymidylate Synthase and Dihydrofolate Reductase Enzymes

    PubMed Central

    Arooj, Mahreen; Sakkiah, Sugunadevi; Cao, Guang ping; Lee, Keun Woo

    2013-01-01

    Due to the diligence of inherent redundancy and robustness in many biological networks and pathways, multitarget inhibitors present a new prospect in the pharmaceutical industry for treatment of complex diseases. Nevertheless, to design multitarget inhibitors is concurrently a great challenge for medicinal chemists. We have developed a novel computational approach by integrating the affinity predictions from structure-based virtual screening with dual ligand-based pharmacophore to discover potential dual inhibitors of human Thymidylate synthase (hTS) and human dihydrofolate reductase (hDHFR). These are the key enzymes in folate metabolic pathway that is necessary for the biosynthesis of RNA, DNA, and protein. Their inhibition has found clinical utility as antitumor, antimicrobial, and antiprotozoal agents. A druglike database was utilized to perform dual-target docking studies. Hits identified through docking experiments were mapped over a dual pharmacophore which was developed from experimentally known dual inhibitors of hTS and hDHFR. Pharmacophore mapping procedure helped us in eliminating the compounds which do not possess basic chemical features necessary for dual inhibition. Finally, three structurally diverse hit compounds that showed key interactions at both active sites, mapped well upon the dual pharmacophore, and exhibited lowest binding energies were regarded as possible dual inhibitors of hTS and hDHFR. Furthermore, optimization studies were performed for final dual hit compound and eight optimized dual hits demonstrating excellent binding features at target systems were also regarded as possible dual inhibitors of hTS and hDHFR. In general, the strategy used in the current study could be a promising computational approach and may be generally applicable to other dual target drug designs. PMID:23577115

  10. Aldosterone alters the participation of endothelial factors in noradrenaline vasoconstriction differently in resistance arteries from normotensive and hypertensive rats.

    PubMed

    Xavier, Fabiano E; Blanco-Rivero, Javier; Avendaño, María Soledad; Sastre, Esther; Yela, Rubén; Velázquez, Kyra; Salaíces, Mercedes; Balfagón, Gloria

    2011-03-11

    This study analyzed the effect of aldosterone (0.05mg/kg per day, 3 weeks) on vasoconstriction induced by noradrenaline in mesenteric resistance arteries from WKY rats and SHR. Contraction to noradrenaline was measured in mesenteric resistance arteries from untreated and aldosterone-treatedrats from both strains. Participation of nitric oxide (NO), superoxide anions, thromboxane A(2) (TxA(2)) and prostacyclin in this response was determined. 6-keto-prostaglandin (PG)F1alpha and thromboxane B(2) (TxB(2)) releases were determined by enzyme immunoassay. NO and superoxide anion release were also determined by fluorescence and chemiluminiscence, respectively. Aldosterone did not modify noradrenaline-induced contraction in either strain. In mesenteric resistance arteries from both aldosterone-treated groups, endothelium removal or preincubation with NO synthesis inhibitor L-NAME increased the noradrenaline-induced contraction, while incubation with the superoxide anion scavenger tempol decreased it. Preincubation with either the COX-1/2 or COX-2 inhibitor (indomethacin and NS-398, respectively) decreased the noradrenaline contraction in aldosterone-treated animals, while this response was not modified by COX-1 inhibitor SC-560. TxA(2) synthesis inhibitor (furegrelate), or TxA2 receptor antagonist (SQ 29 548) also decreased the noradrenaline contraction in aldosterone-treated animals. In untreated SHR, but not WKY rats, this response was increased by L-NAME, and reduced by tempol, indomethacin, NS-398 or SQ 29 548. Aldosterone treatment did not modify NO or TxB(2) release, but it did increase superoxide anion and 6-keto-PGF(1alpha) release in mesenteric resistance arteries from both strains. In conclusion, chronic aldosterone treatment reduces smooth muscle contraction to alpha-adrenergic stimuli, producing a new balance in the release of endothelium-derived prostanoids and NO. PMID:21262224

  11. Plasma concentration of asymmetric dimethylarginine, an endogenous inhibitor of nitric oxide synthase, is elevated in monkeys with hyperhomocyst(e)inemia or hypercholesterolemia.

    PubMed

    Böger, R H; Bode-Böger, S M; Sydow, K; Heistad, D D; Lentz, S R

    2000-06-01

    Hyperhomocyst(e)inemia is associated with endothelial dysfunction. Mechanisms responsible for endothelial dysfunction in hyperhomocyst(e)inemia may involve impaired bioavailability of endothelium-dependent nitric oxide. We tested the hypothesis that hyperhomocyst(e)inemia is associated with an elevated plasma concentration of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of nitric oxide synthase. One group of adult cynomolgus monkeys was fed either a control or hyperhomocyst(e)inemic diet for 4 weeks in a randomized crossover design. The second group was fed an atherogenic diet that produces both hyperhomocyst(e)inemia and hypercholesterolemia for 17 months, followed by an atherogenic diet supplemented with B vitamins for 6 months to decrease plasma homocyst(e)ine concentration. Human endothelial cells were used to study the effects of methionine and homocysteine in the presence or absence of B vitamins or the methylation inhibitor S-adenosylhomocysteine on the formation of ADMA and its inactive stereoisomer, symmetric dimethylarginine. The hyperhomocyst(e)inemic diet produced 2- to 3-fold increases in plasma levels of homocyst(e)ine and ADMA (both P<0.05). The atherogenic diet also produced elevated plasma levels of homocyst(e)ine and ADMA (both P<0. 05). Supplementation of the atherogenic diet with B vitamins decreased the plasma levels of homocyst(e)ine but did not affect the plasma levels of ADMA or endothelial function. There was a strong correlation between plasma ADMA and homocyst(e)ine and a strong inverse correlation between ADMA and carotid artery relaxation to acetylcholine. ADMA release by cultured endothelial cells was significantly increased in the presence of methionine or homocysteine. This effect was blocked by S-adenosylhomocysteine but not by B vitamins. We conclude that plasma levels of ADMA are elevated in hyperhomocyst(e)inemia. Because ADMA acts as a competitive inhibitor of endothelial nitric oxide synthase, these findings

  12. Glial activation is associated with l-DOPA induced dyskinesia and blocked by a nitric oxide synthase inhibitor in a rat model of Parkinson's disease.

    PubMed

    Bortolanza, Mariza; Cavalcanti-Kiwiatkoski, Roberta; Padovan-Neto, Fernando E; da-Silva, Célia Aparecida; Mitkovski, Miso; Raisman-Vozari, Rita; Del-Bel, Elaine

    2015-01-01

    l-3, 4-dihydroxyphenylalanine (L-DOPA) is the most effective treatment for Parkinson's disease but can induce debilitating abnormal involuntary movements (dyskinesia). Here we show that the development of L-DOPA-induced dyskinesia in the rat is accompanied by upregulation of an inflammatory cascade involving nitric oxide. Male Wistar rats sustained unilateral injections of 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle. After three weeks animals started to receive daily treatment with L-DOPA (30 mg/kg plus benserazide 7.5 mg/kg, for 21 days), combined with an inhibitor of neuronal NOS (7-nitroindazole, 7-NI, 30 mg/kg/day) or vehicle (saline-PEG 50%). All animals treated with L-DOPA and vehicle developed abnormal involuntary movements, and this effect was prevented by 7-NI. L-DOPA-treated dyskinetic animals exhibited an increased striatal and pallidal expression of glial fibrillary acidic protein (GFAP) in reactive astrocytes, an increased number of CD11b-positive microglial cells with activated morphology, and the rise of cells positive for inducible nitric oxide-synthase immunoreactivity (iNOS). All these indexes of glial activation were prevented by 7-NI co-administration. These findings provide evidence that the development of L-DOPA-induced dyskinesia in the rat is associated with activation of glial cells that promote inflammatory responses. The dramatic effect of 7-NI in preventing this glial response points to an involvement of nitric oxide. Moreover, the results suggest that the NOS inhibitor prevents dyskinesia at least in part via inhibition of glial cell activation and iNOS expression. Our observations indicate nitric oxide synthase inhibitors as a therapeutic strategy for preventing neuroinflammatory and glial components of dyskinesia pathogenesis in Parkinson's disease. PMID:25447229

  13. Endocrine and Hypertensive Disorders of Potassium Regulation: Primary Aldosteronism

    PubMed Central

    Weiner, I. David

    2013-01-01

    The identification that primary aldosteronism is a common cause of resistant hypertension is a significant advance in our ability to care for patients with hypertension. Primary aldosteronism is common, and when unrecognized is associated with increased incidence of adverse cardiovascular outcomes. Identification of primary aldosteronism is based upon use of the plasma aldosterone level, plasma renin activity and the aldosterone:renin ratio (ARR). Differentiation between unilateral and bilateral autonomous adrenal aldosterone production then guides further therapy, with use of mineralocorticoid receptor blockers for those with bilateral autonomous adrenal aldosterone production and laparoscopic adrenalectomy for those with unilateral autonomous aldosterone production. In this review, we discuss in detail the pathogenesis of primary aldosteronism-induced hypertension and potassium disorders, the evaluation of the patient with suspected primary aldosteronism and the management of primary aldosteronism, both through medications and through surgery. PMID:23953804

  14. Suppression of Aldosterone Secretion After Recumbent Saline Infusion Does Not Exclude Lateralized Primary Aldosteronism.

    PubMed

    Cornu, Erika; Steichen, Olivier; Nogueira-Silva, Luis; Küpers, Elselien; Pagny, Jean-Yves; Grataloup, Christine; Baron, Stéphanie; Zinzindohoue, Franck; Plouin, Pierre-François; Amar, Laurence

    2016-10-01

    Guidelines recommend suppression tests such as the saline infusion test (SIT) to ascertain the diagnosis of primary aldosteronism (PA) in patients with a high aldosterone:renin ratio. However, suppression tests have only been evaluated in small retrospective series, and some experts consider that they are not helpful for the diagnosis of PA. In this study, we evaluated whether low post-SIT aldosterone concentrations do exclude lateralized PA. Between February 2009 and December 2013, 199 patients diagnosed with PA on the basis of 2 elevated aldosterone:renin ratio results and a high basal plasma or urinary aldosterone level or high post-SIT aldosterone level had a selective adrenal venous sampling. We used a selectivity index of 2 and a lateralization index of 4 to interpret the adrenal venous sampling results. Baseline characteristics of the patients were the following (percent or median): men 63%, 48 years old, office blood pressure 142/88 mm Hg, serum potassium 3.4 mmol/L, aldosterone:renin ratio 113 pmol/mU, plasma aldosterone concentration 588 pmol/L. The proportion of patients with lateralized adrenal venous sampling was 12 of 41 (29%) among those with post-SIT aldosterone <139 pmol/L (5 ng/dL) and 38 of 104 (37%) among those with post-SIT aldosterone <277 pmol/L (10 ng/dL). Post-SIT aldosterone levels were not associated with the blood pressure outcome of adrenalectomy. A low post-SIT aldosterone level cannot rule out lateralized PA, even with a low threshold (139 pmol/L). Adrenal venous sampling should be considered for patients who are eligible for surgery with elevated basal aldosterone levels even if they have low aldosterone concentrations after recumbent saline suppression testing. PMID:27600182

  15. Familial varieties of primary aldosteronism.

    PubMed

    Stowasser, M; Gunasekera, T G; Gordon, R D

    2001-12-01

    1. Improved approaches to screening and diagnosis have revealed primary aldosteronism (PAL) to be much more common than previously thought, with most patients normokalaemic. The spectrum of this disorder has been further broadened by the study of familial varieties. 2. Familial hyperaldosteronism type I (FH-I) is a glucocorticoid-remediable form of PAL caused by the inheritance of an adrenocorticotrophic hormone (ACTH)- regulated, hybrid CYP11B1/CYP11B2 gene. Diagnosis has been greatly facilitated by the advent of genetic testing. The severity of hypertension varies widely in FH-I, even among members of the same family, and has demonstrated relationships with gender, degree of biochemical disturbance and hybrid gene crossover point position. Hormone "day curve" studies show that the hybrid gene dominates over wild-type CYP11B2 in terms of aldosterone regulation. This may be due, in part, to a defect in wild-type CYP11B2-induced aldosterone production. Control of hypertension in FH-I requires only partial suppression of ACTH and much smaller glucocorticoid doses than previously recommended. 3. Familial hyperaldosteronism type II (FH-II) is not glucocorticoid remediable and is not associated with the hybrid gene mutation. Familial hyperaldosteronism type II is clinically, biochemically and morphologically indistinguishable from apparently non-familial PAL. Linkage studies in one informative family did not show segregation of FH-II with the CYP11B2, AT1 or MEN1 genes, but a genome-wide search has revealed linkage with a locus in chromosome 7. As has already occurred in FH-I, elucidation of causative mutations is likely to facilitate earlier detection of PAL. PMID:11903322

  16. Screening of inhibitors of glycogen synthase kinase-3β from traditional Chinese medicines using enzyme-immobilized magnetic beads combined with high-performance liquid chromatography.

    PubMed

    Li, Yunfang; Xu, Jia; Chen, Yu; Mei, Zhinan; Xiao, Yuxiu

    2015-12-18

    Glycogen synthase kinase-3β (GSK-3β) was immobilized on magnetic beads (MBs) by affinity method for the first time. The enzyme-immobilized MBs were coupled with high-performance liquid chromatography-ultraviolet (HPLC-UV) technique to establish a cost-effective and reliable method for screening of inhibitors of GSK-3β. A peptide substrate of GSK-3β containing a tyrosine residue was employed since it can be sensitively detected by UV detector at 214nm. The substrate and its phosphorylated product were separated by baseline within 10min. The enzyme activity was determined by the quantification of peak area of the product. Parameters including enzyme immobilization, enzyme reaction and the performance of immobilized-enzyme were investigated. The immobilized enzyme can be reused for 10 times and remain stable for 4 days at 4°C. The inhibitory activities of extracts of 15 traditional Chinese medicines (TCMs) were screened. As a result, three of them including Euonymus fortunei, Amygdalus communis and Garcinia xanthochymus were found possessing high inhibitory activities (inhibition rate >90%). From G. xanthochymus, a new inhibitor of GSK-3β, fukugetin, was discovered with an IC50 value of 3.18±0.07μM. Enzyme kinetics and molecular docking experiments further revealed the inhibitory mechanism, indicating fukugetin was a non-ATP competitive inhibitor interacting with the phosphate recognizing substrate binding site of GSK-3β. PMID:26610618

  17. Glycogen synthase kinase 3 inhibitors induce the canonical WNT/β-catenin pathway to suppress growth and self-renewal in embryonal rhabdomyosarcoma

    PubMed Central

    Chen, Eleanor Y.; DeRan, Michael T.; Ignatius, Myron S.; Grandinetti, Kathryn Brooke; Clagg, Ryan; McCarthy, Karin M.; Lobbardi, Riadh M.; Brockmann, Jillian; Keller, Charles; Wu, Xu; Langenau, David M.

    2014-01-01

    Embryonal rhabdomyosarcoma (ERMS) is a common pediatric malignancy of muscle, with relapse being the major clinical challenge. Self-renewing tumor-propagating cells (TPCs) drive cancer relapse and are confined to a molecularly definable subset of ERMS cells. To identify drugs that suppress ERMS self-renewal and induce differentiation of TPCs, a large-scale chemical screen was completed. Glycogen synthase kinase 3 (GSK3) inhibitors were identified as potent suppressors of ERMS growth through inhibiting proliferation and inducing terminal differentiation of TPCs into myosin-expressing cells. In support of GSK3 inhibitors functioning through activation of the canonical WNT/β-catenin pathway, recombinant WNT3A and stabilized β-catenin also enhanced terminal differentiation of human ERMS cells. Treatment of ERMS-bearing zebrafish with GSK3 inhibitors activated the WNT/β-catenin pathway, resulting in suppressed ERMS growth, depleted TPCs, and diminished self-renewal capacity in vivo. Activation of the canonical WNT/β-catenin pathway also significantly reduced self-renewal of human ERMS, indicating a conserved function for this pathway in modulating ERMS self-renewal. In total, we have identified an unconventional tumor suppressive role for the canonical WNT/β-catenin pathway in regulating self-renewal of ERMS and revealed therapeutic strategies to target differentiation of TPCs in ERMS. PMID:24706870

  18. In-silico docking based design and synthesis of [1H,3H] imidazo[4,5-b] pyridines as lumazine synthase inhibitors for their effective antimicrobial activity

    PubMed Central

    Harer, Sunil L.; Bhatia, Manish S.

    2014-01-01

    Purpose: The imidazopyridine moiety is important pharmacophore that has proven to be useful for a number of biologically relevant targets, also reported to display antibacterial, antifungal, antiviral properties. Riboflavin biosynthesis involving catalytic step of Lumazine synthase is absent in animals and human, but present in microorganism, one of marked advantage of this study. Still, this path is not exploited as antiinfective target. Here, we proposed different interactions between [1H,3H] imidazo[4,5-b] pyridine test ligands and target protein Lumazine synthase (protein Data Bank 2C92), one-step synthesis of title compounds and further evaluation of them for in vitro antimicrobial activity. Materials and Methods: Active pocket of the target protein involved in the interaction with the test ligands molecules was found using Biopredicta tools in VLifeMDS 4.3 Suite. In-silico docking suggests H-bonding, hydrophobic interaction, charge interaction, aromatic interaction, and Vanderwaal forces responsible for stabilizing enzyme-inhibitor complex. Disc diffusion assay method was used for in vitro antimicrobial screening. Results and Discussion: Investigation of possible interaction between test ligands and target lumazine synthase of Mycobacterium tuberculosis suggested 1i and 2f as best fit candidates showing hydrogen bonding, hydrophobic, aromatic and Vanderwaal's forces. Among all derivatives 1g, 1j, 1k, 1l, 2a, 2c, 2d, 2e, 2h, and 2j exhibited potent activities against bacteria and fungi compared to the standard Ciprofloxacin and Fluconazole, respectively. The superiority of 1H imidazo [4,5-b] pyridine compounds having R’ = Cl >No2 > NH2 at the phenyl/aliphatic moiety resident on the imidazopyridine, whereas leading 3H imidazo[4,5-b] pyridine compounds containing R/Ar = Cl > No2 > NH2> OCH3 substituents on the 2nd position of imidazole. PMID:25400412

  19. Structure of N-acetyl-L-glutamate synthase/kinase from Maricaulis maris with the allosteric inhibitor L-arginine bound.

    PubMed

    Zhao, Gengxiang; Haskins, Nantaporn; Jin, Zhongmin; M Allewell, Norma; Tuchman, Mendel; Shi, Dashuang

    2013-08-01

    Maricaulis maris N-acetylglutamate synthase/kinase (mmNAGS/K) catalyzes the first two steps in L-arginine biosynthesis and has a high degree of sequence and structural homology to human N-acetylglutamate synthase, a regulator of the urea cycle. The synthase activity of both mmNAGS/K and human NAGS are regulated by L-arginine, although L-arginine is an allosteric inhibitor of mmNAGS/K, but an activator of human NAGS. To investigate the mechanism of allosteric inhibition of mmNAGS/K by L-arginine, we have determined the structure of the mmNAGS/K complexed with L-arginine at 2.8 Å resolution. In contrast to the structure of mmNAGS/K in the absence of L-arginine where there are conformational differences between the four subunits in the asymmetric unit, all four subunits in the L-arginine liganded structure have very similar conformations. In this conformation, the AcCoA binding site in the N-acetyltransferase (NAT) domain is blocked by a loop from the amino acid kinase (AAK) domain, as a result of a domain rotation that occurs when L-arginine binds. This structural change provides an explanation for the allosteric inhibition of mmNAGS/K and related enzymes by L-arginine. The allosterically regulated mechanism for mmNAGS/K differs significantly from that for Neisseria gonorrhoeae NAGS (ngNAGS). To define the active site, several residues near the putative active site were mutated and their activities determined. These experiments identify roles for Lys356, Arg386, Asn391 and Tyr397 in the catalytic mechanism. PMID:23850694

  20. Structure of N-acetyl-L-glutamate synthase/kinase from Maricaulis maris with the allosteric inhibitor L-arginine bound

    PubMed Central

    Zhao, Gengxiang; Haskins, Nantaporn; Jin, Zhongmin; Allewell, Norma M.; Tuchman, Mendel; Shi, Dashuang

    2013-01-01

    Maricaulis maris N-acetylglutamate synthase/kinase (mmNAGS/K) catalyzes the first two steps in L-arginine biosynthesis and has a high degree of sequence and structural homology to human N-acetylglutamate synthase, a regulator of the urea cycle. The synthase activity of both mmNAGS/K and human NAGS are regulated by L-arginine, although L-arginine is an allosteric inhibitor of mmNAGS/K, but an activator of human NAGS. To investigate the mechanism of allosteric inhibition of mmNAGS/K by L-arginine, we have determined the structure of the mmNAGS/K complexed with L-arginine at 2.8 Å resolution. In contrast to the structure of mmNAGS/K in the absence of L-arginine where there are conformational differences between the four subunits in the asymmetric unit, all four subunits in the L-arginine liganded structure have very similar conformations. In this conformation, the AcCoA binding site in the N-acetyltransferase (NAT) domain is blocked by a loop from the amino acid kinase (AAK) domain, as a result of a domain rotation that occurs when L-arginine binds. This structural change provides an explanation for the allosteric inhibition of mmNAGS/K and related enzymes by L-arginine. The allosterically regulated mechanism for mmNAGS/K differs significantly from that for Neisseria gonorrhoeae NAGS (ngNAGS). To define the active site, several residues near the putative active site were mutated and their activities determined. These experiments identify roles for Lys356, Arg386, Asn391 and Tyr397 in the catalytic mechanism. PMID:23850694

  1. Aldosterone Production and Signaling Dysregulation in Obesity.

    PubMed

    Vecchiola, Andrea; Lagos, Carlos F; Carvajal, Cristian A; Baudrand, Rene; Fardella, Carlos E

    2016-03-01

    In the past decades, we have extended the view of aldosterone effects beyond epithelial tissues. New evidence regarding the aldosterone/mineralocorticoid receptor (MR) pathway in active metabolic tissues, including adipose tissue, has confirmed its pathogenic role in systemic inflammation, endothelial dysfunction, insulin resistance, and dyslipidemia. Obesity, a current epidemic worldwide, increases aldosterone production by several adipocyte factors such as leptin but is also associated with local aldosterone production. In addition, obesity can modulate MR activation leading to signaling dysregulation and a pro-inflammatory profile of adipocytes. Current knowledge have deciphered that this phenotypical differences of obesity may be explained, at least in part, by novel non-genomic activation of MR, new inducers of aldosterone synthesis, and probably by several epigenetic modifications. In addition, with the understanding of the complex interplay of obesity, hormones, and receptors, targeted pharmacological therapy is expected and is currently under active research. PMID:26838033

  2. Effects of the dual TP receptor antagonist and thromboxane synthase inhibitor EV-077 on human endothelial and vascular smooth muscle cells

    SciTech Connect

    Petri, Marcelo H.; Tellier, Céline; Michiels, Carine; Ellertsen, Ingvill; Dogné, Jean-Michel; Bäck, Magnus

    2013-11-15

    Highlights: •EV-077 reduced TNF-α induced inflammation in endothelial cells. •The thromboxane mimetic U69915 enhanced vascular smooth muscle cell proliferation. •EV-077 inhibited smooth muscle cell proliferation. -- Abstract: The prothrombotic mediator thromboxane A{sub 2} is derived from arachidonic acid metabolism through the cyclooxygenase and thromboxane synthase pathways, and transduces its effect through the thromboxane prostanoid (TP) receptor. The aim of this study was to determine the effect of the TP receptor antagonist and thromboxane synthase inhibitor EV-077 on inflammatory markers in human umbilical vein endothelial cells and on human coronary artery smooth muscle cell proliferation. To this end, mRNA levels of different proinflammatory mediators were studied by real time quantitative PCR, supernatants were analyzed by enzyme immune assay, and cell proliferation was assessed using WST-1. EV-077 significantly decreased mRNA levels of ICAM-1 and PTX3 after TNFα incubation, whereas concentrations of 6-keto PGF1α in supernatants of endothelial cells incubated with TNFα were significantly increased after EV-077 treatment. Although U46619 did not alter coronary artery smooth muscle cell proliferation, this thromboxane mimetic enhanced the proliferation induced by serum, insulin and growth factors, which was significantly inhibited by EV-077. In conclusion, EV-077 inhibited TNFα-induced endothelial inflammation and reduced the enhancement of smooth muscle cell proliferation induced by a thromboxane mimetic, supporting that the thromboxane pathway may be associated with early atherosclerosis in terms of endothelial dysfunction and vascular hypertrophy.

  3. Nitro-arginine methyl ester, a non-selective inhibitor of nitric oxide synthase reduces ibuprofen-induced gastric mucosal injury in the rat.

    PubMed

    Abraham, Premila; K, Indirani; K, Desigamani

    2005-09-01

    Ibuprofen is a commonly used non-steroidal anti-inflammatory drug. Gastrointestinal adverse drug reactions from ibuprofen usage include gastric mucosal ulcers and bleeding. The mechanism by which ibuprofen induces gastric mucosal damage is not clear. The present study is an attempt to examine the role of nitric oxide in the pathogenesis of ibuprofen-induced gastric mucosal damage. Ibuprofen administered orally at the dose of 100 mg/kg body weight for 6 days to the rats resulted in gastric mucosal injury. Serum nitrite and nitrosothiol were increased significantly as compared with the controls, which were treated with the vehicle alone. In the gastric mucosa, lipid peroxidation and protein thiols were increased, and the activity of glyceraldehyde 3-phosphate dehydrogenase, a nitric oxide sensitive enzyme was decreased significantly. Pretreatment of the rats daily with nitric oxide synthase inhibitor, nitro-arginine methyl ester (30 mg/kg body weight) 1 hr before treatment with ibuprofen reduced the gastric mucosal injury. Biochemically, it prevented the rise in serum nitrite levels and the increase in lipid peroxidation and protein thiol levels and the loss of glyceraldehyde 3-phosphate dehydrogenase activity in the gastric mucosa. The results of the present study suggest that increased nitric oxide production may be one of the mechanisms by which ibuprofen produces gastric mucosal injury and that inhibition of nitric oxide synthase reduces gastric mucosal injury. PMID:16133962

  4. In silico screening for identification of novel β-1,3-glucan synthase inhibitors using pharmacophore and 3D-QSAR methodologies.

    PubMed

    Meetei, Potshangbam Angamba; Rathore, R S; Prabhu, N Prakash; Vindal, Vaibhav

    2016-01-01

    The enzyme β-1,3-glucan synthase, which catalyzes the synthesis of β-1,3-glucan, an essential and unique structural component of the fungal cell wall, has been considered as a promising target for the development of less toxic anti-fungal agents. In this study, a robust pharmacophore model was developed and structure activity relationship analysis of 42 pyridazinone derivatives as β-1,3-glucan synthase inhibitors were carried out. A five-point pharmacophore model, consisting of two aromatic rings (R) and three hydrogen bond acceptors (A) was generated. Pharmacophore based 3D-QSAR model was developed for the same reported data sets. The generated 3D-QSAR model yielded a significant correlation coefficient value (R (2) = 0.954) along with good predictive power confirmed by the high value of cross-validated correlation coefficient (Q (2) = 0.827). Further, the pharmacophore model was employed as a 3D search query to screen small molecules database retrieved from ZINC to select new scaffolds. Finally, ADME studies revealed the pharmacokinetic efficiency of these compounds. PMID:27429875

  5. Feeding the nitric oxide synthase inhibitor L-N(omega)nitroarginine elevates serum very low density lipoprotein and hepatic triglyceride synthesis in rats.

    PubMed

    Goto, T; Ohnomi, S; Khedara, A; Kato, N; Ogawa, H; Yanagita, T

    1999-05-01

    This study was conducted to study the influence of dietary L-N(omega)nitroarginine (L-NNA), a nitric oxide (NO) synthase inhibitor, on serum lipids and lipoproteins and on the activities of enzymes related to lipid metabolism in rats. Feeding rats a diet containing 0.2 g/kg L-NNA for 5 weeks elevated serum concentrations of triglyceride, cholesterol, phospholipid, and free fatty acid and reduced serum nitrate (an oxidation product of NO). The elevation in serum triglyceride was mainly due to the elevation in very low density lipoprotein (VLDL) triglyceride. Contents of cholesterol and phospholipid in the VLDL fraction also were elevated by L-NNA. L-NNA treatment caused significantly higher activity of hepatic microsomal phosphatidate phosphohydrolase (the rate-limiting enzyme in triglyceride synthesis) and lower activity of hepatic carnitine palmitoyltransferase (the rate-limiting enzyme in fatty acid oxidation). Activities of hepatic enzymes responsible for fatty acid synthesis such as glucose-6-phosphate dehydrogenase, malic enzyme, and fatty acid synthase were unaffected by L-NNA. The activity of hepatic microsomal phosphocholine cytidyltransferase (the rate-limiting enzyme in phosphatidylcholine synthesis) was reduced significantly by L-NNA. Our results suggest that lower NO production caused the elevations in hepatic triglyceride synthesis by higher esterification of fatty acid and lower fatty acid oxidation, leading to an enrichment of VLDL triglyceride. PMID:15539300

  6. Inhibitory activity to protein prenylation and antifungal activity of zaragozic acid D3, a potent inhibitor of squalene synthase produced by the fungus, Mollisia sp. SANK 10294.

    PubMed

    Tanimoto, T; Ohya, S; Tsujita, Y

    1998-04-01

    Recently we found novel zaragozic acids (ZAs), F-10863A (zaragozic acid D3, ZAD3), B, C and D in the culture broth of the fungus Mollisia sp. SANK 10294 as potent inhibitors of squalene synthase. There are several other enzymes that use farnesylpyrophosphate as their substrate. Among them we chose farnesyl-protein transferase and examined whether ZAD3 and F-10863B inhibit this enzyme's activity. ZAD3 and F-10863B inhibited farnesyl-protein transferase with IC50 values of 0.60 and 3.7 microM, respectively. They also inhibited geranylgeranyl-protein transferase at similar concentrations. In addition, they exhibited potent antifungal activity. PMID:9630865

  7. Discovery of a Highly Selective Glycogen Synthase Kinase-3 Inhibitor (PF-04802367) That Modulates Tau Phosphorylation in the Brain: Translation for PET Neuroimaging.

    PubMed

    Liang, Steven H; Chen, Jinshan Michael; Normandin, Marc D; Chang, Jeanne S; Chang, George C; Taylor, Christine K; Trapa, Patrick; Plummer, Mark S; Para, Kimberly S; Conn, Edward L; Lopresti-Morrow, Lori; Lanyon, Lorraine F; Cook, James M; Richter, Karl E G; Nolan, Charlie E; Schachter, Joel B; Janat, Fouad; Che, Ye; Shanmugasundaram, Veerabahu; Lefker, Bruce A; Enerson, Bradley E; Livni, Elijahu; Wang, Lu; Guehl, Nicolas J; Patnaik, Debasis; Wagner, Florence F; Perlis, Roy; Holson, Edward B; Haggarty, Stephen J; El Fakhri, Georges; Kurumbail, Ravi G; Vasdev, Neil

    2016-08-01

    Glycogen synthase kinase-3 (GSK-3) regulates multiple cellular processes in diabetes, oncology, and neurology. N-(3-(1H-1,2,4-triazol-1-yl)propyl)-5-(3-chloro-4-methoxyphenyl)oxazole-4-carboxamide (PF-04802367 or PF-367) has been identified as a highly potent inhibitor, which is among the most selective antagonists of GSK-3 to date. Its efficacy was demonstrated in modulation of tau phosphorylation in vitro and in vivo. Whereas the kinetics of PF-367 binding in brain tissues are too fast for an effective therapeutic agent, the pharmacokinetic profile of PF-367 is ideal for discovery of radiopharmaceuticals for GSK-3 in the central nervous system. A (11) C-isotopologue of PF-367 was synthesized and preliminary PET imaging studies in non-human primates confirmed that we have overcome the two major obstacles for imaging GSK-3, namely, reasonable brain permeability and displaceable binding. PMID:27355874

  8. NO-synthase inhibitors provide influence on protective effect of modified endotoxine diphosphoryl lipid A in a rat heart model of ischemic-reperfusion injury.

    PubMed

    Kuzelová, M; Mladonická, M; Bukovský, M; Dubnicková, M; Adameová, A; Svec, P

    2006-06-01

    The present study was designed to assess whether a protective effect of the modified diphosphoryl lipid A (modLA) against myocardial ischemia-reperfusion injury (IRI) in rats can be related to the mechanism involving inducible nitric oxide synthase (iNOS). Pre-treatment with modLA significantly reduced the duration of both ventricular tachycardia (p < 0.01) and ventricular fibrillation (p < 0.001) compared to controls. Under these conditions the incidence of animal death was reduced (p < 0.05). The beneficial effect of modLA was markedly attenuated by the prior administration of selective iNOS inhibitor S-methylisothiourea (SMT). In this animal group, mortality was significantly increased (p < 0.01) partially in consequence of sustained ventricular arrhythmias. These results indicate that induction of iNOS can be responsible for cardioprotection of modLA. PMID:16826982

  9. Regulation of hypothalamic renin-angiotensin system and oxidative stress by aldosterone

    PubMed Central

    Huang, Bing S; Zheng, Hong; Tan, Junhui; Patel, Kaushik P; Leenen, Frans HH

    2011-01-01

    In rats with salt-induced hypertension or post myocardial infarction (MI), AT1 receptor (AT1R) densities and oxidative stress increase and neuronal nitric oxide synthase (nNOS) levels decrease in the paraventricular nucleus (PVN). The present study was designed to determine whether these changes may depend on activation of the aldosterone – “ouabain” neuromodulatory pathway. After intracerebroventricular (icv) infusion of aldosterone (20ng/h) for 14 days, blood pressure (BP) and heart rate (HR) were recorded in conscious Wistar rats, and mRNA and protein for nNOS, endothelial NOS (eNOS), AT1R and NADPH oxidase subunits were assessed in brain tissue. BP and HR were significantly increased by aldosterone. Aldosterone significantly increased mRNA and protein of AT1R, P22phox, P47phox, P67phox and Nox2, and decreased nNOS but not eNOS mRNA and protein in the PVN, and increased angiotensin converting enzyme (ACE) and AT1R binding densities in the PVN and SON. The increases in BP and HR as well as changes in mRNA, proteins and ACE and AT1R binding densities were all largely prevented by concomitant icv infusion of Digibind (to bind “ouabain”) or benzamil (to block presumably epithelial sodium channels). These data indicate that aldosterone via “ouabain” increases in the PVN ACE, AT1R and oxidative stress but decreases nNOS, and suggest that endogenous aldosterone may cause this similar pattern of changes observed in salt sensitive hypertension and heart failure post MI. PMID:21824999

  10. The effect of nitric oxide synthase inhibitors nitro-L-arginine and 7-nitroindazole on spatial learning and motor functions in Lurcher mutant and wild type mice.

    PubMed

    Markvartová, V; Vozeh, F

    2008-01-01

    Nitric oxide (NO) is an intercellular messenger that, among other things, plays an important role in the nervous system as a gaseous neurotransmitter, modulating long-term potentiation (LTP) induction of synaptic transmission. LTP has been suggested to be the basis of memory formation. On the other hand NO also participates in excitotoxic processes which play an important role in many neuropathological states. The aim of this work was to observe the effect of two NO synthase (NOS) inhibitors (N omega-Nitro-L-arginine, NA; 7-nitroindazole, NI) on spontaneous behaviour, spatial learning and motor functions in Lurcher (+/Lc) and wild type (+/+) mice, derived from the B6CBA strain. Heterozygous Lurcher mutant mice represent a natural model of the olivocerebellar degeneration. They suffer from postnatal, practically total, extinction of cerebellar Purkinje cells (due to the excitotoxic apoptosis) and a partial decrease of granule cells and inferior olive neurons (ION) because of the lost target of their axons. +/+ animals are healthy littermates of +/Lc. NA is a nonselective NOS inhibitor which influences, except neuronal (n), also endothelial (e) NOS with an impact on blood pressure, NI is a selective nNOS inhibitor without any circulatory effect. The adult animals of both types (+/Lc; +/+) were influenced by acute administration of both inhibitors (25 mg/kg i.p. 30 min. before experiments) and newborns only by both acute and long-term administration of NI (1 month, starting from postnatal day 2, P2). Control solutions - saline or solvents of both NA and NI inhibitors--diluted 1M HCl and dimethyl sulfoxide (DMSO) respectively, were given at a relevant volume in the same way. The effect of both inhibitors and control solutions on motor functions was tested using four standard procedures (horizontal wire, slanting ladder, rotating cylinder, foot-bridge); in newborns at the age of 14 days. Spatial learning ability was examined in five-day long procedure in the Morris

  11. In Vitro Activities of ER-119884 and E5700, Two Potent Squalene Synthase Inhibitors, against Leishmania amazonensis: Antiproliferative, Biochemical, and Ultrastructural Effects▿

    PubMed Central

    Fernandes Rodrigues, Juliany Cola; Concepcion, Juan Luis; Rodrigues, Carlos; Caldera, Aura; Urbina, Julio A.; de Souza, Wanderley

    2008-01-01

    ER-119884 and E5700, novel arylquinuclidine derivatives developed as cholesterol-lowering agents, were potent in vitro growth inhibitors of both proliferative stages of Leishmania amazonensis, the main causative agent of cutaneous leishmaniasis in South America, with the 50% inhibitory concentrations (IC50s) being in the low-nanomolar to subnanomolar range. The compounds were very potent noncompetitive inhibitors of native L. amazonensis squalene synthase (SQS), with inhibition constants also being in the nanomolar to subnanomolar range. Growth inhibition was strictly associated with the depletion of the parasite's main endogenous sterols and the concomitant accumulation of exogenous cholesterol. Using electron microscopy, we identified the intracellular structures affected by the compounds. A large number of lipid inclusions displaying different shapes and electron densities were observed after treatment with both SQS inhibitors, and these inclusions were associated with an intense disorganization of the membrane that surrounds the cell body and flagellum, as well as the endoplasmic reticulum and the Golgi complex. Cells treated with ER-119884 but not those treated with E5700 had an altered cytoskeleton organization due to an abnormal distribution of tubulin, and many were arrested at cytokinesis. A prominent contractile vacuole and a phenotype typical of programmed cell death were frequently found in drug-treated cells. The selectivity of the drugs was demonstrated with the JC-1 mitochondrial fluorescent label and by trypan blue exclusion tests with macrophages, which showed that the IC50s against the host cells were 4 to 5 orders of magnitude greater that those against the intracellular parasites. Taken together, our results show that ER-119884 and E5700 are unusually potent and selective inhibitors of the growth of Leishmania amazonensis, probably because of their inhibitory effects on de novo sterol biosynthesis at the level of SQS, but some of our

  12. Structure-Based Design and Synthesis of Nω-Nitro-L-Arginine-Containing Peptidomimetics as Selective Inhibitors of Neuronal Nitric Oxide Synthase. Displacement of the Heme Structural Water

    PubMed Central

    Seo, Jiwon; Igarashi, Jotato; Li, Huiying; Martásek, Pavel; Roman, Linda J.; Poulos, Thomas L.; Silverman, Richard B.

    2008-01-01

    The neuronal isoform of nitric oxide synthase (nNOS), the enzyme responsible for the production of nitric oxide in the central nervous system, represents an attractive target for the treatment of various neurodegenerative disorders. X-ray crystal structures of complexes of nNOS with two nNOS-selective inhibitors, (4S)-N-{4-amino-5-[(2-aminoethylamino]pentyl}-N′-nitroguanidine (1) and 4-N-(Nω-nitro-L-argininyl)-trans-4-amino-L-proline amide (2), led to the discovery of a conserved structural water molecule that was hydrogen bonded between the two heme propionates and the inhibitors (Figure 2). Based on this observation, we hypothesized that by attaching a hydrogen bond donor group to the amide nitrogen of 2 or to the secondary amine nitrogen of 1, the inhibitor molecules could displace the structural water molecule and obtain a direct interaction with the heme cofactor. To test this hypothesis, peptidomimetic analogues 3–5, which have either an N-hydroxyl (3 and 5) or N-amino (4) donor group, were designed and synthesized. X-ray crystal structures of nNOS with inhibitors 3 and 5 bound verified that the N-hydroxyl group had, indeed, displaced the structural water molecule and provided a direct interaction with the heme propionate moiety (Figures 4 and 5). Surprisingly, in vitro activity assay results indicated that the addition of a hydroxyl group (3) only increased the potency slightly against the neuronal isoform over the parent compound (1). Rationalizations for the small increase in potency are consistent with other changes in the crystal structures. PMID:17425297

  13. Minimal Pharmacophoric Elements and Fragment Hopping, an Approach Directed at Molecular Diversity and Isozyme Selectivity. Design of Selective Neuronal Nitric Oxide Synthase Inhibitors

    PubMed Central

    Ji, Haitao; Stanton, Benjamin Z.; Igarashi, Jotaro; Li, Huiying; Martásek, Pavel; Roman, Linda J.; Poulos, Thomas L.; Silverman, Richard B.

    2010-01-01

    Fragment hopping, a new fragment-based approach for de novo inhibitor design focusing on ligand diversity and isozyme selectivity, is described. The core of this approach is the derivation of the minimal pharmacophoric element for each pharmacophore. Sites for both ligand binding and isozyme selectivity are considered in deriving the minimal pharmacophoric elements. Five general-purpose libraries are established: the basic fragment library, the bioisostere library, the rules for metabolic stability, the toxicophore library, and the side chain library. These libraries are employed to generate focused fragment libraries to match the minimal pharmacophoric elements for each pharmacophore and then to link the fragment to the desired molecule. This method was successfully applied to neuronal nitric oxide synthase (nNOS), which is implicated in stroke and neurodegenerative diseases. Starting with the nitroarginine-containing dipeptide inhibitors we developed previously, a small organic molecule with a totally different chemical structure was designed, which showed nanomolar nNOS inhibitory potency and more than 1000-fold nNOS selectivity. The crystallographic analysis confirms that the small organic molecule with a constrained conformation can exactly mimic the mode of action of the dipeptide nNOS inhibitors. Therefore, a new peptidomimetic strategy, referred to as fragment hopping, which creates small organic molecules that mimic the biological function of peptides by a pharmacophore-driven strategy for fragment-based de novo design, has been established as a new type of fragment-based inhibitor design. As an open system, the newly established approach efficiently incorporates the concept of early “ADME/Tox” considerations and provides a basic platform for medicinal chemistry-driven efforts. PMID:18321097

  14. The structure of mollusc larval shells formed in the presence of the chitin synthase inhibitor Nikkomycin Z

    PubMed Central

    Schönitzer, Veronika; Weiss, Ingrid M

    2007-01-01

    Background Chitin self-assembly provides a dynamic extracellular biomineralization interface. The insoluble matrix of larval shells of the marine bivalve mollusc Mytilus galloprovincialis consists of chitinous material that is distributed and structured in relation to characteristic shell features. Mollusc shell chitin is synthesized via a complex transmembrane chitin synthase with an intracellular myosin motor domain. Results Enzymatic mollusc chitin synthesis was investigated in vivo by using the small-molecule drug NikkomycinZ, a structural analogue to the sugar donor substrate UDP-N-acetyl-D-glucosamine (UDP-GlcNAc). The impact on mollusc shell formation was analyzed by binocular microscopy, polarized light video microscopy in vivo, and scanning electron microscopy data obtained from shell material formed in the presence of NikkomycinZ. The partial inhibition of chitin synthesis in vivo during larval development by NikkomycinZ (5 μM – 10 μM) dramatically alters the structure and thus the functionality of the larval shell at various growth fronts, such as the bivalve hinge and the shell's edges. Conclusion Provided that NikkomycinZ mainly affects chitin synthesis in molluscs, the presented data suggest that the mollusc chitin synthase fulfils an important enzymatic role in the coordinated formation of larval bivalve shells. It can be speculated that chitin synthesis bears the potential to contribute via signal transduction pathways to the implementation of hierarchical patterns into chitin mineral-composites such as prismatic, nacre, and crossed-lamellar shell types. PMID:17986326

  15. Aldosterone and type 2 diabetes mellitus.

    PubMed

    Zavatta, Guido; Casadio, Elena; Rinaldi, Eleonora; Pagotto, Uberto; Pasquali, Renato; Vicennati, Valentina

    2016-04-01

    Primary hyperaldosteronism (PA) has recently been demonstrated to be strictly associated to metabolic syndrome as compared with essential hypertension (EH). Besides, the characteristics of metabolic syndrome are different in PA compared to EH, as high fasting glucose is more frequent in the former condition. The adverse effect of excess aldosterone on insulin metabolic signaling has generated increasing interest in the role of hyperaldosteronism in the pathogenesis of insulin resistance and resistant hypertension. Moreover, aldosterone receptor antagonist therapy in diabetic and cardiopathic patients improved coronary flow. The aim of this review is to present recent knowledge about the relationship between aldosterone, insulin resistance and diabetes. PMID:26876814

  16. Inflammatory markers in primary aldosteronism.

    PubMed

    Šomlóová, Z; Petrák, O; Rosa, J; Štrauch, B; Indra, T; Zelinka, T; Haluzík, M; Zikán, V; Holaj, R; Widimský, J

    2016-06-20

    Primary aldosteronism (PA) is the most common cause of endocrine hypertension with a high frequency of cardiovascular complications. The unfavorable cardiometabolic profile may be due to aldosterone-mediated activation of inflammatory cells, circulatory cytokines and activation of collagen synthesis in the vessel wall. Aim of our study was to evaluate differences in the levels of hsCRP, IL-6, TNF-alpha and N-terminal propeptide of collagen I (PINP) in patients with PA and essential hypertension (EH) as a control group, and between the subtypes of PA (aldosterone producing adenoma - APA, idiopathic hyperaldosteronism - IHA). We studied 28 patients with PA (IHA - 10 patients, APA - 12 patients, 6 unclassified) and 28 matched patients with EH. There were no differences in the levels of inflammatory markers between the followed groups [EH vs. PA: TNF-alpha (5.09 [3.68-6.32] vs. 4.84 [3.62-6.50] pg/ml), IL-6 (0.94 [0.70-1.13] vs. 0.97 [0.71-1.28] pg/ml), hsCRP (0.53 [0.25-1.54] vs. 0.37 [0.31-0.61] mg/l), leukocytes (6.35+/-1.42 vs. 5.97+/-1.29 10(9) l); APA vs. IHA: TNF-alpha (4.54 [3.62-7.03] vs. 5.19 [4.23-5.27] pg/ml), IL-6 (0.96 [0.63-1.21] vs. 0.90 [0.65-1.06] pg/ml), hsCRP (0.34 [0.29-0.47] vs. 0.75 [0.36-1.11] mg/l), leukocytes (6.37+/-1.41 vs. 5.71+/-1.21 10(9) l)]. Significant differences in the levels of PINP between PA and EH group were observed (35.18 [28.46-41.16] vs. 45.21 [36.95-62.81] microg/l, p

  17. Statins and the squalene synthase inhibitor zaragozic acid stimulate the non-amyloidogenic pathway of amyloid-beta protein precursor processing by suppression of cholesterol synthesis.

    PubMed

    Kojro, Elzbieta; Füger, Petra; Prinzen, Claudia; Kanarek, Anna Maria; Rat, Dorothea; Endres, Kristina; Fahrenholz, Falk; Postina, Rolf

    2010-01-01

    Cholesterol-lowering drugs such as statins influence the proteolytic processing of the amyloid-beta protein precursor (AbetaPP) and are reported to stimulate the activity of alpha-secretase, the major preventive secretase of Alzheimer's disease. Statins can increase the alpha-secretase activity by their cholesterol-lowering properties as well as by impairment of isoprenoids synthesis. In the present study, we elucidate the contribution of these pathways in alpha-secretase activation. We demonstrate that zaragozic acid, a potent inhibitor of squalene synthase which blocks cholesterol synthesis but allows synthesis of isoprenoids, also stimulates alpha-secretase activity. Treatment of human neuroblastoma cells with 50 microM zaragozic acid resulted in a approximately 3 fold increase of alpha-secretase activity and reduced cellular cholesterol by approximately 30%. These effects were comparable to results obtained from cells treated with a low lovastatin concentration (2 microM). Zaragozic acid-stimulated secretion of alpha-secretase-cleaved soluble AbetaPP was dose dependent and saturable. Lovastatin- or zaragozic acid-stimulated increase of alpha-secretase activity was completely abolished by a selective ADAM10 inhibitor. By targeting the alpha-secretase ADAM10 to lipid raft domains via a glycosylphosphatidylinositol anchor, we demonstrate that ADAM10 is unable to cleave AbetaPP in a cholesterol-rich environment. Our results indicate that inhibition of cholesterol biosynthesis by a low lovastatin concentration is sufficient for alpha-secretase activation. PMID:20413873

  18. The role of S-methylisothiourea hemisulfate as inducible nitric oxide synthase inhibitor against kidney iron deposition in iron overload rats

    PubMed Central

    Maleki, Maryam; Samadi, Melika; Khanmoradi, Mehrangiz; Nematbakhsh, Mehdi; Talebi, Ardeshir; Nasri, Hamid

    2016-01-01

    Background: Iron dextran is in common use to maintain iron stores. However, it is potentially toxic and may lead to iron deposition (ID) and impair functions of organs. Iron overload can regulate the expression of inducible nitric oxide synthase (iNOS) in some cells that has an important role in tissue destruction. S-methylisothiourea hemisulfate (SMT) is a direct inhibitor of iNOS, and this study was designed to investigate the effect of SMT against kidney ID in iron overload rats. Materials and Methods: 24 Wistar rats (male and female) were randomly assigned to two groups. Iron overloading was performed by iron dextran 100 mg/kg/day every other day for 2 weeks. In addition, during the study, groups 1 and 2 received vehicle and SMT (10 mg/kg, ip), respectively. Finally, blood samples were obtained, and the kidneys were prepared for histopathological procedures. Results: SMT significantly reduced the serum levels of creatinine and blood urea nitrogen. However, SMT did not alter the serum levels of iron and nitrite, and the kidney tissue level of nitrite. Co-administration of SMT with iron dextran did not attenuate the ID in the kidney. Conclusion: SMT, as a specific iNOS inhibitor, could not protect the kidney from ID while it attenuated the serum levels of kidney function biomarkers. PMID:27308268

  19. High resolution genetic mapping uncovers chitin synthase-1 as the target-site of the structurally diverse mite growth inhibitors clofentezine, hexythiazox and etoxazole in Tetranychus urticae

    PubMed Central

    Demaeght, Peter; Osborne, Edward J.; Odman-Naresh, Jothini; Grbić, Miodrag; Nauen, Ralf; Merzendorfer, Hans

    2014-01-01

    The acaricides clofentezine, hexythiazox and etoxazole are commonly referred to as ‘mite growth inhibitors’, and clofentezine and hexythiazox have been used successfully for the integrated control of plant mite pests for decades. Although they are still important today, their mode of action has remained elusive. Recently, a mutation in chitin synthase 1 (CHS1) was linked to etoxazole resistance. In this study, we identified and investigated a T. urticae strain (HexR) harboring recessive, monogenic resistance to each of hexythiazox, clofentezine, and etoxazole. To elucidate if there is a common genetic basis for the observed cross-resistance, we adapted a previously developed bulk segregant analysis method to map with high resolution a single, shared resistance locus for all three compounds. This finding indicates that the underlying molecular basis for resistance to all three compounds is identical. This locus is centered on the CHS1 gene, and as supported by additional genetic and biochemical studies, a non-synonymous variant (I1017F) in CHS1 associates with resistance to each of the tested acaricides in HexR. Our findings thus demonstrate a shared molecular mode of action for the chemically diverse mite growth inhibitors clofentezine, hexythiazox and etoxazole as inhibitors of an essential, non-catalytic activity of CHS1. Given the previously documented cross-resistance between clofentezine, hexythiazox and the benzyolphenylurea compounds flufenoxuron and cycloxuron, CHS1 should be also considered as a potential target-site of insecticidal BPUs. PMID:24859419

  20. The use of aminoguanidine, a selective inducible nitric oxide synthase inhibitor, to evaluate the role of nitric oxide on periapical healing

    PubMed Central

    Farhad, Ali Reza; Razavi, Seyed Mohammad; Nejad, Parnian Alavi

    2011-01-01

    Background: Nitric oxide (NO) is one of the many chemical mediators involved in inflammatory processes. In addition to periapical inflammation, NO can have a role in periapical healing. The purpose of this study was to evaluate the effect of aminoguanidine (AG) as a selective inhibitor of inducible nitric oxide synthase (iNOS) on the degree of healing response of periapical lesions of the canine teeth of cats. Methods: In this interventional experimental study, the root canals of 48 cat canine teeth were infected with cat dental plaque and sealed. After induction of periapical lesions, root canal therapy (RCT) was performed. On the day of RCT phase, the cats were administered either AG (experimental group) or normal saline (control group), which was continued on a daily basis until the day of sacrifice. Four canine teeth in one cat served as negative and positive controls. The animals were sacrificed 6 weeks after RCT. The healing response of the periapical zones was analyzed histologically. The mean scores of healing for the two groups were compared using Mann–Whitney U test. Results: The mean scores of healing for the AG group (2.45±0.508) were significantly higher than those of the control group (2±0.510) (P<0.05). Conclusion: The use of an iNOS selective inhibitor such as AG can accelerate the healing process in periapical lesions. PMID:22135691

  1. Structure-Based Design of Novel Pyrimido[4,5-c]pyridazine Derivatives as Dihydropteroate Synthase Inhibitors with Increased Affinity

    SciTech Connect

    Zhao, Ying; Hammoudeh, Dalia; Yun, Mi-Kyung; Qi, Jianjun; White, Stephen W.; Lee, Richard E.

    2012-05-29

    Dihydropteroate synthase (DHPS) is the validated drug target for sulfonamide antimicrobial therapy. However, due to widespread drug resistance and poor tolerance, the use of sulfonamide antibiotics is now limited. The pterin binding pocket in DHPS is highly conserved and is distinct from the sulfonamide binding site. It therefore represents an attractive alternative target for the design of novel antibacterial agents. We previously carried out the structural characterization of a known pyridazine inhibitor in the Bacillus anthracis DHPS pterin site and identified a number of unfavorable interactions that appear to compromise binding. With this structural information, a series of 4,5-dioxo-1,4,5,6-tetrahydropyrimido[4,5-c]pyridazines were designed to improve binding affinity. Most importantly, the N-methyl ring substitution was removed to improve binding within the pterin pocket, and the length of the side chain carboxylic acid was optimized to fully engage the pyrophosphate binding site. These inhibitors were synthesized and evaluated by an enzyme activity assay, X-ray crystallography, isothermal calorimetry, and surface plasmon resonance to obtain a comprehensive understanding of the binding interactions from structural, kinetic, and thermodynamic perspectives. This study clearly demonstrates that compounds lacking the N-methyl substitution exhibit increased inhibition of DHPS, but the beneficial effects of optimizing the side chain length are less apparent.

  2. Thiolactomycin-based β-ketoacyl-AcpM synthase A (KasA) inhibitors: fragment-based inhibitor discovery using transient one-dimensional nuclear overhauser effect NMR spectroscopy.

    PubMed

    Kapilashrami, Kanishk; Bommineni, Gopal R; Machutta, Carl A; Kim, Pilho; Lai, Cheng-Tsung; Simmerling, Carlos; Picart, Francis; Tonge, Peter J

    2013-03-01

    Thiolactomycin (TLM) is a natural product inhibitor of KasA, the β-ketoacyl synthase A from Mycobacterium tuberculosis. To improve the affinity of TLM for KasA, a series of TLM analogs have been synthesized based on interligand NOEs between TLM and a pantetheine analog when both are bound simultaneously to the enzyme. Kinetic binding data reveal that position 3 of the thiolactone ring is a suitable position for elaboration of the TLM scaffold, and the structure-activity relationship studies provide information on the molecular features that govern time-dependent inhibition in this enzyme system. These experiments also exemplify the utility of transient one-dimensional NOE spectroscopy for obtaining interligand NOEs compared with traditional steady state two-dimensional NOESY spectroscopy. PMID:23306195

  3. Serum aldosterone and death, end-stage renal disease, and cardiovascular events in blacks and whites: findings from the Chronic Renal Insufficiency Cohort (CRIC) Study.

    PubMed

    Deo, Rajat; Yang, Wei; Khan, Abigail M; Bansal, Nisha; Zhang, Xiaoming; Leonard, Mary B; Keane, Martin G; Soliman, Elsayed Z; Steigerwalt, Susan; Townsend, Raymond R; Shlipak, Michael G; Feldman, Harold I

    2014-07-01

    Prior studies have demonstrated that elevated aldosterone concentrations are an independent risk factor for death in patients with cardiovascular disease. Limited studies, however, have evaluated systematically the association between serum aldosterone and adverse events in the setting of chronic kidney disease. We investigated the association between serum aldosterone and death and end-stage renal disease in 3866 participants from the Chronic Renal Insufficiency Cohort. We also evaluated the association between aldosterone and incident congestive heart failure and atherosclerotic events in participants without baseline cardiovascular disease. Cox proportional hazards models were used to evaluate independent associations between elevated aldosterone concentrations and each outcome. Interactions were hypothesized and explored between aldosterone and sex, race, and the use of loop diuretics and renin-angiotensin-aldosterone system inhibitors. During a median follow-up period of 5.4 years, 587 participants died, 743 developed end-stage renal disease, 187 developed congestive heart failure, and 177 experienced an atherosclerotic event. Aldosterone concentrations (per SD of the log-transformed aldosterone) were not an independent risk factor for death (adjusted hazard ratio, 1.00; 95% confidence interval, 0.93-1.12), end-stage renal disease (adjusted hazard ratio, 1.07; 95% confidence interval, 0.99-1.17), or atherosclerotic events (adjusted hazard ratio, 1.04; 95% confidence interval, 0.85-1.18). Aldosterone was associated with congestive heart failure (adjusted hazard ratio, 1.21; 95% confidence interval, 1.02-1.35). Among participants with chronic kidney disease, higher aldosterone concentrations were independently associated with the development of congestive heart failure but not for death, end-stage renal disease, or atherosclerotic events. Further studies should evaluate whether mineralocorticoid receptor antagonists may reduce adverse events in individuals with

  4. Identification of novel membrane-associated prostaglandin E synthase-1 (mPGES-1) inhibitors with anti-influenza activities in vitro.

    PubMed

    Park, Ji Hoon; Park, Eun Beul; Lee, Jae Yeol; Min, Ji-Young

    2016-01-22

    Influenza A virus (IAV) is a major public health concern that leads to high morbidity and mortality worldwide. Despite various vaccination programs and development of drugs targeting essential viral proteins, the emergence of drug-resistant variants has been frequently reported and the therapeutic options are limited. Because exaggerated inflammation is considered as an important factor in disease pathogenesis, immunomodulatory agents that effectively suppress cytokine responses are needed for the treatment of IAV infection. Membrane-associated prostaglandin E synthase-1 (mPGES-1) is an enzyme responsible for the production of prostaglandin E2 (PGE2) that is the best-characterized immune modulatory lipid in vitro and in vivo models of inflammation. In the present study, we tested the anti-influenza activities of mPGES-1 inhibitors, using a phenotype-based assay involving image analyses. Seven primary hits among 49 compounds targeting mPGES-1 exhibited anti-influenza activities against A/Puerto Rico/8/1934 (H1N1) in a dose-dependent manner. The most effective hit, MPO-0047, suppressed influenza-induced p38 mitogen-activated protein kinase (MAPK), and c-Jun N-terminal kinase (JNK) activation. We also showed that mRNA levels of TNF-α, IL-8, CCL5/RANTES, and CXCL10/IP-10 were significantly reduced by the treatment of influenza-infected cells with MPO-0047. Exogenous PGE2 reversed the inhibitory effects of MPO-0047. Our results showed that this selective mPGES-1 inhibitor has anti-influenza effects by inhibiting PGE2 production, which suppresses the induction of pro-inflammatory genes. Taken together our data revealed that mPGES-1 inhibitor has the potential for further development as an influenza therapeutic agent. PMID:26673392

  5. Structure determination of glycogen synthase kinase-3 from Leishmania major and comparative inhibitor structure-activity relationships with Trypanosoma brucei GSK-3

    SciTech Connect

    Ojo, Kayode K; Arakaki, Tracy L; Napuli, Alberto J; Inampudi, Krishna K; Keyloun, Katelyn R; Zhang, Li; Hol, Wim G.J.; Verlind, Christophe L.M.J.; Merritt, Ethan A; Van Voorhis, Wesley C

    2012-04-24

    Glycogen synthase kinase-3 (GSK-3) is a drug target under intense investigation in pharmaceutical companies and constitutes an attractive piggyback target for eukaryotic pathogens. Two different GSKs are found in trypanosomatids, one about 150 residues shorter than the other. GSK-3 short (GeneDB: Tb927.10.13780) has previously been validated genetically as a drug target in Trypanosoma brucei by RNAi induced growth retardation; and chemically by correlation between enzyme and in vitro growth inhibition. Here, we report investigation of the equivalent GSK-3 short enzymes of L. major (LmjF18.0270) and L. infantum (LinJ18_V3.0270, identical in amino acid sequences to LdonGSK-3 short) and a crystal structure of LmajGSK-3 short at 2 Å resolution. The inhibitor structure-activity relationships (SARs) of L. major and L. infantum are virtually identical, suggesting that inhibitors could be useful for both cutaneous and visceral leishmaniasis. Leishmania spp. GSK-3 short has different inhibitor SARs than TbruGSK-3 short, which can be explained mostly by two variant residues in the ATP-binding pocket. Indeed, mutating these residues in the ATP-binding site of LmajGSK-3 short to the TbruGSK-3 short equivalents results in a mutant LmajGSK-3 short enzyme with SAR more similar to that of TbruGSK-3 short. The differences between human GSK-3β (HsGSK-3β) and LmajGSK-3 short SAR suggest that compounds which selectively inhibit LmajGSK-3 short may be found.

  6. Detection, Diagnosis, and Treatment of Primary Aldosteronism

    MedlinePlus

    ... that results when one or both of your adrenal glands (small glands about the size of a prune ... aldosterone is a benign (noncancerous) tumor in one adrenal gland or if both adrenal glands are overactive. A ...

  7. Aldosterone Inactivates the Endothelin-B Receptor via a Cysteinyl Thiol Redox Switch to Decrease Pulmonary Endothelial Nitric Oxide Levels and Modulate Pulmonary Arterial Hypertension

    PubMed Central

    Maron, Bradley A.; Zhang, Ying-Yi; White, Kevin; Chan, Stephen Y.; Handy, Diane E.; Mahoney, Christopher E.; Loscalzo, Joseph; Leopold, Jane A.

    2012-01-01

    Background Pulmonary arterial hypertension (PAH) is characterized, in part, by decreased endothelial nitric oxide (NO•) production and elevated levels of endothelin-1. Endothelin-1 is known to stimulate endothelial nitric oxide synthase (eNOS) via the endothelin-B receptor (ETB), suggesting that this signaling pathway is perturbed in PAH. Endothelin-1 also stimulates adrenal aldosterone synthesis; in systemic blood vessels, hyperaldosteronism induces vascular dysfunction by increasing endothelial reactive oxygen species (ROS) generation and decreasing NO• levels. We hypothesized that aldosterone modulates PAH by disrupting ETB-eNOS signaling through a mechanism involving increased pulmonary endothelial oxidant stress. Methods and Results In rats with PAH, elevated endothelin-1 levels were associated with elevated aldosterone levels in plasma and lung tissue and decreased lung NO• metabolites in the absence of left heart failure. In human pulmonary artery endothelial cells (HPAECs), endothelin-1 increased aldosterone levels via PGC-1α/steroidogenesis factor-1-dependent upregulation of aldosterone synthase. Aldosterone also increased ROS production, which oxidatively modified cysteinyl thiols in the eNOS-activating region of ETB to decrease endothelin-1-stimulated eNOS activity. Substitution of ETB-Cys405 with alanine improved ETB-dependent NO• synthesis under conditions of oxidant stress, confirming that Cys405 is a redox sensitive thiol that is necessary for ETB-eNOS signaling. In HPAECs, mineralocorticoid receptor antagonism with spironolactone decreased aldosterone-mediated ROS generation and restored ETB-dependent NO• production. Spironolactone or eplerenone prevented or reversed pulmonary vascular remodeling and improved cardiopulmonary hemodynamics in two animal models of PAH in vivo. Conclusions Our findings demonstrate that aldosterone modulates an ETB cysteinyl thiol redox switch to decrease pulmonary endothelium-derived NO• and promote PAH

  8. Cytochrome P450 CYP81A12 and CYP81A21 Are Associated with Resistance to Two Acetolactate Synthase Inhibitors in Echinochloa phyllopogon1[W

    PubMed Central

    Iwakami, Satoshi; Endo, Masaki; Saika, Hiroaki; Okuno, Junichi; Nakamura, Naoki; Yokoyama, Masao; Watanabe, Hiroaki; Toki, Seiichi; Uchino, Akira; Inamura, Tatsuya

    2014-01-01

    Previous studies have demonstrated multiple herbicide resistance in California populations of Echinochloa phyllopogon, a noxious weed in rice (Oryza sativa) fields. It was suggested that the resistance to two classes of acetolactate synthase-inhibiting herbicides, bensulfuron-methyl (BSM) and penoxsulam (PX), may be caused by enhanced activities of herbicide-metabolizing cytochrome P450. We investigated BSM metabolism in the resistant (R) and susceptible (S) lines of E. phyllopogon, which were originally collected from different areas in California. R plants metabolized BSM through O-demethylation more rapidly than S plants. Based on available information about BSM tolerance in rice, we isolated and analyzed P450 genes of the CYP81A subfamily in E. phyllopogon. Two genes, CYP81A12 and CYP81A21, were more actively transcribed in R plants compared with S plants. Transgenic Arabidopsis (Arabidopsis thaliana) expressing either of the two genes survived in media containing BSM or PX at levels at which the wild type stopped growing. Segregation of resistances in the F2 generation from crosses of R and S plants suggested that the resistance to BSM and PX were each under the control of a single regulatory element. In F6 recombinant inbred lines, BSM and PX resistances cosegregated with increased transcript levels of CYP81A12 and CYP81A21. Heterologously produced CYP81A12 and CYP81A21 proteins in yeast (Saccharomyces cerevisiae) metabolized BSM through O-demethylation. Our results suggest that overexpression of the two P450 genes confers resistance to two classes of acetolactate synthase inhibitors to E. phyllopogon. The overexpression of the two genes could be regulated simultaneously by a single trans-acting element in the R line of E. phyllopogon. PMID:24760819

  9. 16-Aza-ent-beyerane and 16-Aza-ent-trachylobane: Potent Mechanism-based Inhibitors of Recombinant ent-Kaurene Synthase from Arabidopsis thaliana1

    PubMed Central

    Roy, Arnab; Roberts, Frank G.; Wilderman, P. Ross; Zhou, Ke; Peters, Reuben J.; Coates, Robert M.

    2013-01-01

    The secondary ent-beyeran-16-yl carbocation (7) is a key branch point intermediate in mechanistic schemes to rationalize the cyclic structures of many tetra- and pentacyclic diterpenes including ent-beyerene, ent-kaurene, ent-trachylobane, and ent-atiserene, presumed precursors to > 1,000 known diterpenes. (Scheme 1) To evaluate these mechanistic hypotheses, we synthesized the heterocyclic analogues, 16-aza-ent-beyerane (12) and 16-aza-ent-trachylobane (13), by means of Hg(II)- and Pb(IV)-induced cyclizations onto the Δ12 double bonds of tricyclic intermediates bearing carbamoylmethyl and aminomethyl groups at C-8. The 13,16-seco 16-nor carbamate (20a) was obtained from ent-beyeran-16-one oxime (17) by Beckmann fragmentation, hydrolysis, and Curtius rearrangement. The aza analogues inhibited recombinant ent-kaurene synthase from Arabidopsis thaliana (GST-rAtKS) with inhibition constants (IC = 1 × 10 −7 and 1 × 10−6 50 M) similar in magnitude to the pseudo-binding constant of the bicyclic ent-copalyl diphosphate substrate (Km = 3 × 10−7 M). Large enhancements of binding affinities (IC50 = 4 × 10−9 and 2 × 10−8 M) were observed in the presence of 1 mM pyrophosphate which is consistent with a tightly bound ent-beyeranyl+/pyrophosphate− ion pair intermediate in the cyclization-rearrangement catalyzed by this diterpene synthase. The weak inhibition (IC50 = 1 × 10−5 M) exhibited by ent-beyeran-16 exo-yl diphosphate (11), and its failure to undergo bridge rearrangement to kaurene, appear to rule out the covalent diphosphate as a free intermediate. 16-Aza-ent-beyerane is proposed as an effective mimic for the ent-beyeran-16-yl carbocation with potential applications as an active site probe for the various ent- diterpene cyclases, and as a novel, selective inhibitor of gibberellin biosynthesis in plants. PMID:17892288

  10. Alkaloids as Inhibitors of Malate Synthase from Paracoccidioides spp.: Receptor-Ligand Interaction-Based Virtual Screening and Molecular Docking Studies, Antifungal Activity, and the Adhesion Process

    PubMed Central

    Costa, Fausto Guimaraes; Neto, Benedito Rodrigues da Silva; Gonçalves, Ricardo Lemes; da Silva, Roosevelt Alves; de Oliveira, Cecília Maria Alves; Kato, Lucília; Freitas, Carla dos Santos; Giannini, Maria José Soares Mendes; da Silva, Julhiany de Fátima; Soares, Célia Maria de Almeida

    2015-01-01

    Paracoccidioides is the agent of paracoccidioidomycosis. Malate synthase plays a crucial role in the pathogenicity and virulence of various fungi, such as those that are human pathogens. Thus, an inhibitor of this enzyme may be used as a powerful antifungal without side effects in patients once these enzymes are absent in humans. Here, we searched for compounds with inhibitory capacity against the malate synthase of Paracoccidioides species (PbMLS). The three-dimensional (3D) structure of PbMLS was determined using the I-TASSER server. Compounds were selected from the ZINC database. Based on the mechanism underlying the interaction of the compounds with PbMLS, it was possible to identify β-carboline moiety as a standard key structure. The compounds with β-carboline moiety that are available in our laboratories were investigated. A total of nine alkaloid compounds were selected. The primary mechanisms of interaction of the alkaloid compounds in the binding pocket of PbMLS were identified and compared with the mechanism of interaction of acetyl coenzyme A (acetyl-CoA). We discovered that the amphipathic nature of the compounds, concomitant with the presence of β-carboline moiety, was crucial for their stability in the binding pocket of PbMLS. In addition, the importance of a critical balance of the polar and nonpolar contacts of the compounds in this region was observed. Four β-carboline alkaloid compounds showed the ability to inhibit recombinant PbMLS (PbMLSr) activity, Paracoccidioides species growth, and adhesion of the fungus and PbMLSr to the extracellular matrix components. The cytotoxicity of the alkaloids was also evaluated. PMID:26124176

  11. Stimulation and suppression of aldosterone in plasma of normal man and in primary aldosteronism

    PubMed Central

    Horton, R.

    1969-01-01

    The effect of stimulating and suppressive influences on plasma aldosterone in normal man and in patients with primary aldosteronism were studied using a sensitive double-isotope derivative assay for aldosterone. In normal sitting subjects, values were 9.2±0.9 (SE) mμg/100 ml and in subjects supine for 1 hr plasma aldosterone was 5.2±0.4 (SE) mμg/100 ml. Adrenocorticotropic hormone (ACTH), 0.5 U/hr, produced a rise of 46.8±22 (SE) mμg which was similar to the 1-hr effect of an infusion of a synthetic ACTH (β1-24, Cortrosyn). Angiotensin II in pressor amounts also increased plasma aldosterone 21.5±2.9 (SE) without change in plasma cortisol, whereas a subpressor dose ([unk]) had minimal effect. Fludrocortisone, 1.2 mg/day for 3 days, suppressed plasma aldosterone levels to 1.8±0.7 (SE) mμg/100 ml in five normal sitting subjects (P < 0.01); however, dexamethasone, 2 mg/day for 1-2 days, did not lower aldosterone concentration in plasma. In six patients with primary aldosteronism, plasma aldosterone on a normal sodium diet was 39.1±4.4 (SE) which differed significantly from normal sitting or supine subjects (P < 0.001). In contrast to the normal subjects, neither a pressor infusion of angiotensin II for 1 hr, nor fludrocortisone, 1.2 mg/day for 3 days, impressively altered plasma aldosterone levels. This approach appears to be useful for the study of the acute physiology and control mechanisms of aldosterone production in normal and hypertensive man. PMID:4307457

  12. Molecular Docking Studies of Catechin and Its Derivatives as Anti-bacterial Inhibitor for Glucosamine-6-Phosphate Synthase

    NASA Astrophysics Data System (ADS)

    Fikrika, H.; Ambarsari, L.; Sumaryada, T.

    2016-01-01

    Molecular docking simulation of catechin and its derivatives on Glucosamine-6- Phosphate Synthase (GlmS) has been performed in this research. GlmS inhibition by a particular ligand will suppress the production of bacterial cell wall and significantly reduce the population of invading bacteria. In this study, catechin derivatives i.e epicatechin, galloatechin and epigalloatechin were found to have stronger binding affinities as compared to natural ligand of GlmS, Fructose-6-Phosphate (F6P). Those three ligands were docked on the same pocket in GlmS target as F6P, with 70% binding sites similarity. Based on the docking results, gallocatechin turns out to be the most potent ligand for anti-bacterial agent with ΔG= -8.00 kcal/mol. The docking between GlmS and catechin derivatives are characterized by a constant present of a strong hydrogen bond between functional group O3 and Ser-349. This hydrogen bond most likely plays a significant role in the docking mechanism and binding modes selection. The surprising result is catechin itself exhibited a quite strong binding with GlmS (ΔG= -7.80 kcal.mol), but docked on a completely different pocket compared to other ligands. This results suggest that catechin might still have a curing effect but with a completely different pathway and mechanism as compared to its derivatives.

  13. Single dose of inducible nitric oxide synthase inhibitor induces prolonged inflammatory cell accumulation and fibrosis around injured tendon and synovium.

    PubMed

    Darmani, Homa; Crossan, James C; Curtis, Adam

    2004-06-01

    The aim of the current study was to investigate the effect of inhibition of nitric oxide (NO) production after injury on inflammatory cell accumulation and fibrosis around digital flexor tendon and synovium. A standard crush injury was applied to the flexor tendons of the middle digit of the hindpaw and the overlying muscle and synovium of female Wistar rats. Thirty animals received an intraperitoneal injection of either isotonic saline or N(G)-nitro-l-arginine methyl ester (L-NAME; 5 mg/kg) immediately following the crush injury, and five animals were then sacrificed at various intervals and the paws processed for histology. Another group of five animals was sacrificed after 3 days for nitrite determinations. The results showed that nitrite production and hence NO synthase activity is doubled at the acute phase of tendon wound healing, and we can prevent this by administering a single dose of L-NAME immediately after injury. The incidence and severity of fibrocellular adhesions between tendon and synovium was much more marked in animals treated with L-NAME. Treatment with L-NAME elicited a chronic inflammatory response characterised by a persistent and extraordinarily severe accumulation of large numbers of inflammatory cells in the subcutaneous tissues, in muscle and in tendon. These findings indicate that in the case of injured tendon and synovium, NO could act to protect the healing tissue from an uncontrolled inflammatory response. PMID:15223606

  14. Human stem cell osteoblastogenesis mediated by novel glycogen synthase kinase 3 inhibitors induces bone formation and a unique bone turnover biomarker profile in rats

    SciTech Connect

    Gilmour, Peter S.; O'Shea, Patrick J.; Fagura, Malbinder; Pilling, James E.; Sanganee, Hitesh; Wada, Hiroki; Courtney, Paul F.; Kavanagh, Stefan; Hall, Peter A.; Escott, K. Jane

    2013-10-15

    Wnt activation by inhibiting glycogen synthase kinase 3 (GSK-3) causes bone anabolism in rodents making GSK-3 a potential therapeutic target for osteoporotic and osteolytic metastatic bone disease. To understand the wnt pathway related to human disease translation, the ability of 3 potent inhibitors of GSK-3 (AZD2858, AR79, AZ13282107) to 1) drive osteoblast differentiation and mineralisation using human adipose-derived stem cells (hADSC) in vitro; and 2) stimulate rat bone formation in vivo was investigated. Bone anabolism/resorption was determined using clinically relevant serum biomarkers as indicators of bone turnover and bone formation assessed in femurs by histopathology and pQCT/μCT imaging. GSK-3 inhibitors caused β-catenin stabilisation in human and rat mesenchymal stem cells, stimulated hADSC commitment towards osteoblasts and osteogenic mineralisation in vitro. AZD2858 produced time-dependent changes in serum bone turnover biomarkers and increased bone mass over 28 days exposure in rats. After 7 days, AZD2858, AR79 or AZ13282107 exposure increased the bone formation biomarker P1NP, and reduced the resorption biomarker TRAcP-5b, indicating increased bone anabolism and reduced resorption in rats. This biomarker profile was differentiated from anabolic agent PTH{sub 1–34} or the anti-resorptive Alendronate-induced changes. Increased bone formation in cortical and cancellous bone as assessed by femur histopathology supported biomarker changes. 14 day AR79 treatment increased bone mineral density and trabecular thickness, and decreased trabecular number and connectivity assessed by pQCT/μCT. GSK-3 inhibition caused hADSC osteoblastogenesis and mineralisation in vitro. Increased femur bone mass associated with changes in bone turnover biomarkers confirmed in vivo bone formation and indicated uncoupling of bone formation and resorption. - Highlights: • Wnt modulation with 3 novel GSK-3 inhibitors alters bone growth. • Human stem cell osteoblastogenesis

  15. MITOCHONDRIA-TARGETED CARDIOPROTECTION IN ALDOSTERONISM

    PubMed Central

    Shahbaz, Atta U.; Kamalov, German; Zhao, Wenyuan; Zhao, Tieqiang; Johnson, Patti L.; Sun, Yao; Bhattacharya, Syamal K.; Ahokas, Robert A.; Gerling, Ivan C.; Weber, Karl T.

    2010-01-01

    Chronic aldosterone/salt treatment (ALDOST) is accompanied by an adverse structural remodeling of myocardium that includes multiple foci of microscopic scarring representing morphologic footprints of cardiomyocyte necrosis. Our previous studies suggested that signal-transducer-effector pathway leading to necrotic cell death during ALDOST includes intramitochondrial Ca2+ overloading, together with an induction of oxidative stress and opening of the mitochondrial permeability transition pore (mPTP). To further validate this concept, we hypothesized mitochondria-targeted interventions will prove cardioprotective. Accordingly, 8-wk-old male Sprague-Dawley rats receiving 4 wks ALDOST were cotreated with either quercetin (Q), a flavonoid with mitochondrial antioxidant properties, or cyclosporine A (CsA), an mPTP inhibitor, and compared to ALDOST alone or untreated, age-/sex-matched controls. We monitored: mitochondrial free Ca2+ and biomarkers of oxidative stress, including 8-isoprostane and H2O2 production; mPTP opening; total Ca2+ in cardiac tissue; collagen volume fraction (CVF) to quantify replacement fibrosis, a biomarker of cardiomyocyte necrosis; and employed TUNEL assay to address apoptosis in coronal sections of ventricular myocardium. Compared to controls, at 4 wks ALDOST we found: a marked increase in mitochondrial H2O2 production and 8-isoprostane levels, an increased propensity for mPTP opening, and greater concentrations of mitochondrial free [Ca2+]m and total tissue Ca2+, coupled with a 5-fold rise in CVF without any TUNEL-based evidence of cardiomyocyte apoptosis. Each of these pathophysiologic responses to ALDOST were prevented by Q or CsA cotreatment. Thus, mitochondria play a central role in initiating the cellular-molecular pathway that leads to necrotic cell death and myocardial scarring. This destructive cycle can be interrupted and myocardium salvaged with its structure preserved by mitochondria-targeted cardioprotective strategies. PMID:20966765

  16. Liver-specific mono-unsaturated fatty acid synthase-1 inhibitor for anti-hepatitis C treatment.

    PubMed

    Nio, Yasunori; Hasegawa, Hikari; Okamura, Hitomi; Miyayama, Yohei; Akahori, Yuichi; Hijikata, Makoto

    2016-08-01

    Recently, direct antiviral agents against hepatitis C virus (HCV) infection have been developed as highly effective anti-HCV drugs. However, the appearance of resistant viruses against direct anti-viral agents is an unsolved problem. One of the strategies considered to suppress the emergence of the drug-resistant viruses is to use drugs inhibiting the host factor, which contributes to HCV proliferation, in combination with direct anti-viral agents. The replication complex was reported to be present in the membranous compartment in the cells. Thus, lipid metabolism modulators are good candidates to regulate virus assembly and HCV replication. Recent studies have shown that stearoyl-CoA desaturase (SCD), an enzyme for long-chain mono-unsaturated fatty acid (LCMUFA) synthesis, is a key factor that defines HCV replication efficiency. Systemic exposure to SCD-1 inhibor induces some side effects in the eyes and skin. Thus, systemic SCD-1 inhibitors are considered inappropriate for HCV therapy. To avoid the side effects of systemic SCD-1 inhibitors, the liver-specific SCD-1 inhibitor, MK8245, was synthesized; it showed antidiabetic effects in diabetic model mice with no side effects. In the phase 1 clinical study on measurement of MK8245 tolerability, no significant side effects were reported (ClinicalTrials.gov Identifier: NCT00790556). Therefore, we thought liver-specific SCD-1 inhibitors would be suitable agents for HCV-infected patients. MK8245 was evaluated using recombinant HCV culture systems. Considering current HCV treatments, to avoid the emergence of direct anti-viral agents-resistant viruses, combination therapy with direct anti-viral agents and host-targeted agents would be optimal. With this viewpoint, we confirmed MK8245's additive or synergistic anti-HCV effects on current direct anti-viral agents and interferon-alpha therapy. The results suggest that MK8245 is an option for anti-HCV multi-drug therapy with a low risk of emergence of drug-resistant HCV

  17. Attenuation of acute nitrogen mustard-induced lung injury, inflammation and fibrogenesis by a nitric oxide synthase inhibitor

    SciTech Connect

    Malaviya, Rama; Venosa, Alessandro; Hall, LeRoy; Gow, Andrew J.; Sinko, Patrick J.; Laskin, Jeffrey D.; Laskin, Debra L.

    2012-12-15

    Nitrogen mustard (NM) is a toxic vesicant known to cause damage to the respiratory tract. Injury is associated with increased expression of inducible nitric oxide synthase (iNOS). In these studies we analyzed the effects of transient inhibition of iNOS using aminoguanidine (AG) on NM-induced pulmonary toxicity. Rats were treated intratracheally with 0.125 mg/kg NM or control. Bronchoalveolar lavage fluid (BAL) and lung tissue were collected 1 d–28 d later and lung injury, oxidative stress and fibrosis assessed. NM exposure resulted in progressive histopathological changes in the lung including multifocal lesions, perivascular and peribronchial edema, inflammatory cell accumulation, alveolar fibrin deposition, bronchiolization of alveolar septal walls, and fibrosis. This was correlated with trichrome staining and expression of proliferating cell nuclear antigen (PCNA). Expression of heme oxygenase (HO)-1 and manganese superoxide dismutase (Mn-SOD) was also increased in the lung following NM exposure, along with levels of protein and inflammatory cells in BAL, consistent with oxidative stress and alveolar-epithelial injury. Both classically activated proinflammatory (iNOS{sup +} and cyclooxygenase-2{sup +}) and alternatively activated profibrotic (YM-1{sup +} and galectin-3{sup +}) macrophages appeared in the lung following NM administration; this was evident within 1 d, and persisted for 28 d. AG administration (50 mg/kg, 2 ×/day, 1 d–3 d) abrogated NM-induced injury, oxidative stress and inflammation at 1 d and 3 d post exposure, with no effects at 7 d or 28 d. These findings indicate that nitric oxide generated via iNOS contributes to acute NM-induced lung toxicity, however, transient inhibition of iNOS is not sufficient to protect against pulmonary fibrosis. -- Highlights: ► Nitrogen mustard (NM) induces acute lung injury and fibrosis. ► Pulmonary toxicity is associated with increased expression of iNOS. ► Transient inhibition of iNOS attenuates acute

  18. Mechanisms of acquired resistance to the quinazoline thymidylate synthase inhibitor ZD1694 (Tomudex) in one mouse and three human cell lines.

    PubMed Central

    Jackman, A. L.; Kelland, L. R.; Kimbell, R.; Brown, M.; Gibson, W.; Aherne, G. W.; Hardcastle, A.; Boyle, F. T.

    1995-01-01

    Four cell lines, the mouse L1210 leukaemia, the human W1L2 lymphoblastoid and two human ovarian (CH1 and 41M) cell lines, were made resistant to ZD1694 (Tomudex) by continual exposure to incremental doses of the drug. A 500-fold increase in thymidylate synthase (TS) activity is the primary mechanism of resistance to ZD1694 in the W1L2:RD1694 cell line, which is consequently highly cross-resistant to other folate-based TS inhibitors, including BW1843U89, LY231514 and AG337, but sensitive to antifolates with other enzyme targets. The CH1:RD1694 cell line is 14-fold resistant to ZD1694, largely accounted for by the 4.2-fold increase in TS activity. Cross-resistance was observed to other TS inhibitors, including 5-fluorodeoxyuridine (FdUrd). 41M:RD1694 cells, when exposed to 0.1 microM [3H]ZD1694, accumulated approximately 20-fold less 3H-labelled material over 24 h than the parental line. Data are consistent with this being the result of impaired transport of the drug via the reduced folate/methotrexate carrier. Resistance was therefore observed to methotrexate but not to CB3717, a compound known to use this transport mechanism poorly. The mouse L1210:RD1694 cell line does not accumulate ZD1694 or Methotrexate (MTX) polyglutamates. Folylpolyglutamate synthetase substrate activity (using ZD1694 as the substrate) was decreased to approximately 13% of that observed in the parental line. Cross-resistance was found to those compounds known to be active through polyglutamation. PMID:7537518

  19. Exploring the allosteric mechanism of dihydrodipicolinate synthase by reverse engineering of the allosteric inhibitor binding sites and its application for lysine production.

    PubMed

    Geng, Feng; Chen, Zhen; Zheng, Ping; Sun, Jibin; Zeng, An-Ping

    2013-03-01

    Dihydrodipicolinate synthase (DHDPS, EC 4.2.1.52) catalyzes the first committed reaction of L-lysine biosynthesis in bacteria and plants and is allosterically regulated by L-lysine. In previous studies, DHDPSs from different species were proved to have different sensitivity to L-lysine inhibition. In this study, we investigated the key determinants of feedback regulation between two industrially important DHDPSs, the L-lysine-sensitive DHDPS from Escherichia coli and L-lysine-insensitive DHDPS from Corynebacterium glutamicum, by sequence and structure comparisons and site-directed mutation. Feedback inhibition of E. coli DHDPS was successfully alleviated after substitution of the residues around the inhibitor's binding sites with those of C. glutamicum DHDPS. Interestingly, mutagenesis of the lysine binding sites of C. glutamicum DHDPS according to E. coli DHDPS did not recover the expected feedback inhibition but an activation of DHDPS by L-lysine, probably due to differences in the allosteic signal transduction in the DHDPS of these two organisms. Overexpression of L-lysine-insensitive E. coli DHDPS mutants in E. coli MG1655 resulted in an improvement of L-lysine production yield by 46 %. PMID:22644522

  20. Effects of nitric oxide synthase inhibitor ω-Nitro-L-Arginine Methyl Ester, on silica-induced inflammatory reaction and apoptosis

    PubMed Central

    Wang, He; Leigh, James

    2006-01-01

    Background Although nitric oxide is overproduced by macrophages and neutrophils after exposure to silica, its role in silica-induced inflammatory reaction and apoptosis needs further clarification. In this study, rats were intratracheally instilled with either silica suspension or saline to examine inflammatory reactions and intraperitoneally injected with ω-nitro-L-arginine methyl ester (L-NAME), an inhibitor of nitric oxide synthases, or saline to examine the possible role of nitric oxide production in the reaction. Results Results showed that silica instillation induced a strong inflammatory reaction indicated by increased total cell number, number of neutrophils, protein concentration and lactate dehydrogenase (LDH) activity in bronchoalveolar lavage fluid (BALF). There were no significant differences in these indices between silica-instilled groups with and without L-NAME injection (p > 0.05) except LDH level. The results also showed that apoptotic leucocytes were identified in BALF cells of silica-instilled groups whereas no significant difference was found between silica-instilled groups with and without L-NAME injection in the apoptotic reaction (p > 0.05). Silica instillation significantly increased the level of BALF nitrite/nitrate and L-NAME injection reduced this increase. Conclusion Intratracheal instillation of silica caused an obvious inflammatory reaction and leucocyte apoptosis, but these reactions were not influenced by intraperitoneal injection of L-NAME and reduced production of NO. This supports the possibility that silica-induced lung inflammation and BALF cell apoptosis are via NO-independent mechanisms. PMID:17090306

  1. Design, Synthesis, Calorimetry and Crystallographic analysis of 2-Alkylaminoethyl-1,1-Bisphosphonates as inhibitors of Trypanosoma cruzi Farnesyl Diphosphate Synthase

    PubMed Central

    Aripirala, Srinivas; Szajnman, Sergio H.; Jakoncic, Jean; Rodriguez, Juan B.; Docampo, Roberto; Gabelli, Sandra B.; Amzel, L. Mario

    2016-01-01

    Linear 2-alkylaminoethyl-1,1-bisphosphonates are effective agents against proliferation of Trypanosoma cruzi--the etiologic agent of American trypanosomiasis (Chagas disease)--exhibiting IC50 values in the nanomolar range against the parasites. This activity is associated with inhibition at the low nanomolar level of the T. cruzi farnesyl diphosphate synthase (TcFPPS). X-ray structures and thermodynamic data of the complexes TcFPPS with five compounds of this family show that the inhibitors bind to the allylic site of the enzyme with their alkyl chain occupying the cavity that binds the isoprenoid chain of the substrate. The compounds bind to TcFPPS with unfavorable enthalpy compensated by a favorable entropy that results from a delicate balance between two opposing effects: the loss of conformational entropy due to freezing of single bond rotations, and the favorable burial of the hydrophobic alkyl chains. The data suggest that introduction of strategically placed double bonds and methyl branches should increase affinity substantially. PMID:22715997

  2. Effect of 7-nitroindazole, a selective neuronal nitric oxide synthase inhibitor, on parvalbumin immunoreactivity after cerebral ischaemia in the hippocampus of the Mongolian gerbil.

    PubMed

    Kwon, Y B; Yoon, Y S; Han, H J; Lee, J H

    1999-12-01

    Previous studies have demonstrated that a loss of parvalbumin-immunoreactive (PV-ir) neurones is observed in the hippocampus after transient cerebral ischaemia. However, whether the loss of parvalbumin (PV) immunoreactivity is related to the over-production of nitric oxide (NO) during cerebral ischaemia has not been evaluated. This study was designed to test the effect of 7-nitroindazole pre-treatment (7-NI, 50 mg/kg), a selective neuronal NO synthase inhibitor, on PV immunoreactivity and its cellular activity following forebrain ischaemia. PV-ir neurones in the hippocampus of the control group were widely distributed in the pyramidal cell layer and stratum oriens of CA1 and CA3, and the granular cell layer of dentate gyrus. 7-NI pre-treatment completely suppressed the reduction of PV immunoreactivity in CA1 that was observed in the ischaemia-induced group. Subsequently, 7-NI pre-treatment also protected against the structural loss of microtubule-associated protein 2 (MAP2) immunoreactivity in CA1 after ischaemic insult. In addition, the Fos-defined neuronal activity of PV-ir neurones was slightly increased by the 7-NI pre-treatment 3 h after ischaemia. Based on these data, we conclude that the neuronal toxicity of NO may be involved in the loss of PV-ir neurones after cerebral ischaemia. PMID:10652828

  3. The neuronal nitric oxide synthase inhibitor NANT blocks acetaminophen toxicity and protein nitration in freshly isolated hepatocytes.

    PubMed

    Banerjee, Sudip; Melnyk, Stepan B; Krager, Kimberly J; Aykin-Burns, Nukhet; Letzig, Lynda G; James, Laura P; Hinson, Jack A

    2015-12-01

    3-Nitrotyrosine (3NT) in liver proteins of mice treated with hepatotoxic doses of acetaminophen (APAP) has been postulated to be causative in toxicity. Nitration is by a reactive nitrogen species formed from nitric oxide (NO). The source of the NO is unclear. iNOS knockout mice were previously found to be equally susceptible to APAP toxicity as wildtype mice and iNOS inhibitors did not decrease toxicity in mice or in hepatocytes. In this work we examined the potential role of nNOS in APAP toxicity in hepatocytes using the specific nNOS inhibitor NANT (10 µM)(N-[(4S)-4-amino-5-[(2-aminoethyl)amino]pentyl]-N'-nitroguanidinetris (trifluoroacetate)). Primary hepatocytes (1 million/ml) from male B6C3F1 mice were incubated with APAP (1mM). Cells were removed and assayed spectrofluorometrically for reactive nitrogen and oxygen species using diaminofluorescein (DAF) and Mitosox red, respectively. Cytotoxicity was determined by LDH release into media. Glutathione (GSH, GSSG), 3NT, GSNO, acetaminophen-cysteine adducts, NAD, and NADH were measured by HPLC. APAP significantly increased cytotoxicity at 1.5-3.0 h. The increase was blocked by NANT. NANT did not alter APAP mediated GSH depletion or acetaminophen-cysteine adducts in proteins which indicated that NANT did not inhibit metabolism. APAP significantly increased spectroflurometric evidence of reactive nitrogen and oxygen formation at 0.5 and 1.0 h, respectively, and increased 3NT and GSNO at 1.5-3.0 h. These increases were blocked by NANT. APAP dramatically increased NADH from 0.5-3.0 h and this increase was blocked by NANT. Also, APAP decreased the Oxygen Consumption Rate (OCR), decreased ATP production, and caused a loss of mitochondrial membrane potential, which were all blocked by NANT. PMID:26454079

  4. SFE/SFHTA/AFCE consensus on primary aldosteronism, part 7: Medical treatment of primary aldosteronism.

    PubMed

    Pechère-Bertschi, Antoinette; Herpin, Daniel; Lefebvre, Hervé

    2016-07-01

    Spironolactone, which is a potent mineralocorticoid receptor antagonist, represents the first line medical treatment of primary aldosteronism (PA). As spironolactone is also an antagonist of the androgen and progesterone receptor, it may present side effects, especially in male patients. In case of intolerance to spironolactone, amiloride may be used to control hypokaliemia and we suggest that eplerenone, which is a more selective but less powerful antagonist of the mineralocorticoid receptor, be used in case of intolerance to spironolactone and insufficient control of hypertension by amiloride. Specific calcic inhibitors and thiazide diuretics may be used as second or third line therapy. Medical treatment of bilateral forms of PA seem to be as efficient as surgical treatment of lateralized PA for the control of hypertension and the prevention of cardiovascular and renal morbidities. This allows to propose medical treatment of PA to patients with lateralized forms of PA who refuse surgery or to patients with PA who do not want to be explored by adrenal venous sampling to determine whether they have a bilateral or lateralized form. PMID:27315759

  5. Inhibitor of neuronal nitric oxide synthase improves gas exchange in ventilator-induced lung injury after pneumonectomy

    PubMed Central

    2012-01-01

    Background Mechanical ventilation with high tidal volumes may cause ventilator-induced lung injury (VILI) and enhanced generation of nitric oxide (NO). We demonstrated in sheep that pneumonectomy followed by injurious ventilation promotes pulmonary edema. We wished both to test the hypothesis that neuronal NOS (nNOS), which is distributed in airway epithelial and neuronal tissues, could be involved in the pathogenesis of VILI and we also aimed at investigating the influence of an inhibitor of nNOS on the course of VILI after pneumonectomy. Methods Anesthetized sheep underwent right pneumonectomy, mechanical ventilation with tidal volumes (VT) of 6 mL/kg and FiO2 0.5, and were subsequently randomized to a protectively ventilated group (PROTV; n = 8) keeping VT and FiO2 unchanged, respiratory rate (RR) 25 inflations/min and PEEP 4 cm H2O for the following 8 hrs; an injuriously ventilated group with VT of 12 mL/kg, zero end-expiratory pressure, and FiO2 and RR unchanged (INJV; n = 8) and a group, which additionally received the inhibitor of nNOS, 7-nitroindazole (NI) 1.0 mg/kg/h intravenously from 2 hours after the commencement of injurious ventilation (INJV + NI; n = 8). We assessed respiratory, hemodynamic and volumetric variables, including both the extravascular lung water index (EVLWI) and the pulmonary vascular permeability index (PVPI). We measured plasma nitrite/nitrate (NOx) levels and examined lung biopsies for lung injury score (LIS). Results Both the injuriously ventilated groups demonstrated a 2–3-fold rise in EVLWI and PVPI, with no significant effects of NI. In the INJV group, gas exchange deteriorated in parallel with emerging respiratory acidosis, but administration of NI antagonized the derangement of oxygenation and the respiratory acidosis significantly. NOx displayed no significant changes and NI exerted no significant effect on LIS in the INJV group. Conclusion Inhibition of nNOS improved gas exchange, but did not

  6. Anti-ischaemic efficacy of a nitric oxide synthase inhibitor and a N-methyl-D-aspartate receptor antagonist in models of transient and permanent focal cerebral ischaemia.

    PubMed

    Dawson, D A; Graham, D I; McCulloch, J; Macrae, I M

    1994-09-01

    1. We have recently developed a new model of transient focal ischaemia in the rat utilising topical application of endothelin-1 to the left middle cerebral artery (MCA). In order to validate this approach the present study assessed the neuroprotective efficacy of the NMDA receptor antagonist dizocilpine (MK-801) in the endothelin-1 model. The anti-ischaemic efficacy of the nitric oxide (NO) synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) was subsequently evaluated, and contrasted with its efficacy against permanent focal ischaemia, to determine the utility of the endothelin-1 model for identification of novel pharmacoprotective agents. 2. MK-801 (0.12 mg kg-1 bolus, 108 micrograms kg-1 h-1 infusion i.v., either 1 or 2.5 h pre-transient MCA occlusion (MCAO)) induced hypotension that persisted for approximately 1.5 h so that mean arterial blood pressure (MABP) at the time of MCAO was significantly lower in the 1 h group compared with control (MABP: 86 +/- 11, 68 +/- 6 and 84 +/- 4 mmHg (mean +/- s.d.) for saline, 1 h MK-801 and 2.5 h MK-801 groups respectively). The 2.5 h pretreatment schedule resulted in significant reduction (71%) in the volume of hemispheric damage (assessed 4 h post onset of ischaemia) while the 1 h pretreatment schedule did not (volumes of hemispheric damage: 59 +/- 38, 51 +/- 51 and 17 +/- 28 mm3 for saline, 1 h and 2.5 h MK-801 groups). 3. Thus the considerable neuroprotective effect of MK-801 in the endothelin-1 model of transient focal cerebral ischaemia was highly sensitive to drug-induced hypotension. This result is in contrast to previous studies of permanent MCAO where MK-801-induced hypotension did not compromise its neuroprotective action.4. L-NAME (3 mg kg-1, i.v. 30 min pre-MCAO) moderately, but significantly, reduced (16%) the volume of ischaemic damage 4 h post-permanent MCA occlusion, whereas the 29% reduction in volume of damage achieved in the model of transient focal ischaemia did not attain significance due to the

  7. Purification, Characterization, and Identification of Novel Inhibitors of the β-Ketoacyl-Acyl Carrier Protein Synthase III (FabH) from Staphylococcus aureus

    PubMed Central

    He, Xin; Reynolds, Kevin A.

    2002-01-01

    Staphylococcus aureus is a versatile and dangerous pathogen and one of the major causes of community-acquired and hospital-acquired infections. The rise of multidrug-resistant strains of S. aureus requires the development of new antibiotics with previously unexploited mechanisms of action, such as inhibition of the β-ketoacyl-acyl carrier protein (ACP) synthase III (FabH). This enzyme initiates fatty acid biosynthesis in a bacterial type II fatty acid synthase, catalyzing a decarboxylative condensation between malonyl-ACP and an acyl coenzyme A (CoA) substrate and is essential for viability. We have identified only one fabH in the genome of S. aureus and have shown that it encodes a protein with 57, 40, and 34% amino acid sequence identity with the FabH proteins of Bacillus subtilis (bFabH1), Escherichia coli (ecFabH), and Mycobacterium tuberculosis (mtFabH). Additional genomic sequence analysis revealed that this S. aureus FabH (saFabH) is not mutated in certain methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) strains. saFabH was expressed in E. coli with an N-terminal polyhistidine tag and subsequently purified by metal chelate and size exclusion chromatography. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed a molecular mass of 37 kDa, while gel filtration demonstrated a mass of 66.7 kDa, suggesting a noncovalent homodimeric structure for saFabH. The apparent Km for malonyl-ACP was 1.76 ± 0.40 μM, and the enzyme was active with acetyl-CoA (kcat, 16.18 min−1; Km, 6.18 ± 0.9 μM), butyryl-CoA (kcat, 42.90 min−1; Km, 2.32 ± 0.12 μM), and isobutyryl-CoA (kcat, 98.0 min−1; Km, 0.32 ± 0.04 μM). saFabH was weakly inhibited by thiolactomycin (50% inhibitory concentration [IC50], >100 μM) yet was efficiently inhibited by two new FabH inhibitors, 5-chloro-4-phenyl-[1,2]-dithiol-3-one (IC50, 1.87 ± 0.10 μM) and 4-phenyl-5-phenylimino-[1,2,4]dithiazolidin-3-one (IC50, 0.775 ± 0.08 μM). PMID

  8. An open-label phase 2 study of glycogen synthase kinase-3 inhibitor LY2090314 in patients with acute leukemia.

    PubMed

    Rizzieri, David A; Cooley, Sarah; Odenike, Olatoyosi; Moonan, Lisette; Chow, Kay Hoong; Jackson, Kimberley; Wang, Xuejing; Brail, Leslie; Borthakur, Gautam

    2016-08-01

    This open-label, Phase-2 study investigated the safety of LY2090314 (GSK-3 inhibitor) in AML patients. Twenty patients received 40-mg LY2090314 (50-mg ranitidine pretreatment) as follows: Cohort 1 - days 1, 8, and 15 of a 28-d cycle (n = 7); Cohort 2 - days 1, 5, and 9 of a 21-d cycle (n = 6); Cohort 3 - days 1, 5, 9, and 12 of a 21-d cycle (n = 7). Decreased appetite (n = 7) and nausea (n = 4) were the most frequently reported possibly drug-related non-hematologic treatment-emergent adverse events (TEAEs). Hematologic TEAEs included febrile neutropenia (n = 2), thrombocytopenia (n = 1), and anemia (n = 1). Atrial flutter (n = 1), QT interval prolongation (n = 3), and visual disturbances (n = 2) were observed, but were not clinically significant (investigator assessed). Although β-catenin levels indicated an on-target effect, no complete or partial remissions were observed. Pharmacokinetics were consistent with a previous Phase 1 study. These data suggest that single-agent LY2090314 has acceptable safety but limited clinical benefit in AML patients at the dose/frequencies investigated. PMID:26735141

  9. Some considerations about evolution of idiopathic primary aldosteronism.

    PubMed

    Armanini, D; Fiore, C

    2009-07-01

    The prevalence of primary aldosteronism has increased since many patients who were previously considered as being affected by low renin essential hypertension are actually satisfying the new diagnostic criteria using plasma aldosterone/ plasma renin activity (PRA) ratio. Many of these cases could be classified as subclinical hyperaldosteronism, having normal aldosterone and low PRA, or in alternative the normal range of aldosterone should be revised. Idiopathic hyperaldosteronism can, in many cases, be considered as an evolutive disease: it can be hypothesized that the biochemical picture can be preceded by essential hypertension and that, after several years, primary aldosteronism can evolve back to essential hypertension due to age-related reduced vascular and adrenal sensitivity to angiotensin II. This effect is also evident after longterm treatment with aldosterone receptors blockers and therefore it possible that aldosterone-receptors blockers are able to normalize the sensitivity of glomerulosa to angiotensin II even after long-term withdrawal. The use of aldosterone receptors blockers prevents cardiovascular complications due to local aldosterone effect at the level of endothelium and mononuclear leukocytes; therefore, these drugs should be also considered for therapy of patients with hypertension. It is not excluded that aldosterone receptor blockers could prevent the onset of idiopathic hyperaldosteronism and its complications in patients with hypertension without primary hyperaldosteronism. From all these considerations it follows that the concept of normal range of aldosterone should be revised and the use of aldosterone receptor blockers should be revisited. PMID:19893360

  10. Recent advances in diagnosis and treatment of primary aldosteronism.

    PubMed

    Veglio, F; Morello, F; Rabbia, F; Leotta, G; Mulatero, P

    2003-08-01

    Primary aldosteronism is the most common form of secondary hypertension. The use of aldosterone/plasma renin activity ratio (ARR) as a screening test has elevated its prevalence up to 10% of hypertensive patients. Idiopathic bilateral adrenal hyperplasia and aldosterone-producing adrenal adenoma are the leading causes of primary aldosteronism. Most patients with this conditions are normokalemic and clinically undistinguishable from essential hypertensives. However, they suffer from anticipated and more severe target organ damage than other hypertensives. Thus, being primary aldosteronism a common, specifically treatable and sometimes surgically cured form of hypertension, a prompt diagnosis is necessary and cannot be overlooked. The measurement of ambulatory ARR represents the screening test and should be performed in the majority of hypertensive patients. ARR higher than a set cutoff suggests the need of a confirmatory test for primary aldosteronism, such as intravenous saline load or fludrocortisone suppression test. If inability to suppress aldosterone is demonstrated, the disease is confirmed. The subtype evaluation is based on adrenal imaging (CT scan) and selective adrenal venous sampling. The latter is the gold standard for the diagnosis of a lateralized aldosterone secretion, as typically observed in aldosterone-producing adenomas. Microadenomas are frequently overlooked by adrenal image. If lateralization is confirmed, unilateral adrenalectomy is the reasonable therapeutic option, leading to a significant reduction of blood pressure, if not normotension. If bilateral aldosterone excess is demonstrated, an aldosterone receptor antagonist should be administered. This article reviews and discusses the new data about prevalence, diagnosis and treatment of primary aldosteronism. PMID:14605590

  11. Aldosterone increases the apical Na sup + permeability of toad bladder by two different mechanisms

    SciTech Connect

    Asher, C.; Garty, H. )

    1988-10-01

    The aldosterone-induced augmentation of Na{sup +} transport in toad bladder was analyzed by comparing the hormonal actions on the transepithelial short-circuit current and on the amiloride-sensitive {sup 22}Na{sup +} uptake in isolated membrane vesicles. Incubating bladders with 0.5 {mu}M aldosterone for 3 hr evoked more than a 2-fold increase of the short-circuit current but had no effect on the amiloride-sensitive Na{sup +} transport in apical vesicles derived from the treated tissue. A longer incubation produced an additional augmentation of the short-circuit current, which was accompanied by about a 3-fold increase of the channel activity in isolated membranes. The stimulatory effect of aldosterone sustained in vesicles was inhibited by the antagonist spironolactone and the protein synthesis inhibitor cycloheximide. It is suggested that aldosterone elevates the apical Na{sup +} permeability of target epithelia by two different mechanisms: a relatively fast effect which is insensitive to triiodothyronine or butyrate and is not sustained by the isolated membrane, and a slower or later response blocked by these reagents, which is preserved by the isolated membrane. The data also indicate that these processes are mediated by different nuclear receptors.

  12. Effects of S-ethylisothiourea, a potent inhibitor of nitric oxide synthase, alone or in combination with a nitric oxide donor in splanchnic artery occlusion shock.

    PubMed Central

    Squadrito, F.; Altavilla, D.; Squadrito, G.; Campo, G. M.; Ioculano, M.; Canale, P.; Rossi, F.; Saitta, A.; Caputi, A. P.

    1996-01-01

    1. The aim of this study was to compare the effects of an intravenous infusion of a potent and non selective nitric oxide synthase inhibitor S-ethylisothiourea (Ethyl-TU) with that of a nitric oxide (NO) donor on the pathological sequelae associated with splanchnic artery occlusion (SAO) shock. In addition the effects of the combination of these two treatments were also investigated. 2. SAO shock was induced in anaesthetized rats by clamping splanchnic arteries for 45 min. Sham operated animals were used as controls. Survival time, white blood cell (WBC) count, mean arterial blood pressure, myeloperoxidase activity (MPO; studied as a quantitative means to evaluate neutrophil accumulation) and the responsiveness of aortic rings to acetylcholine (ACh, 10 nM-10 microM) and to phenylephrine (PE, 1 nM-10 microM) were studied. 3. SAO shocked rats had a decreased survival rate (0% survival 2 h after the release of occlusion) and survival time (76 +/- 10 min), increased MPO activity in the ileum (3.39 +/- 0.8 u x 10(-3) g-1 tissue), a marked leukopenia and a profound hypotension. In addition aortic rings from shocked rats showed a marked hyporeactivity to PE and reduced responsiveness to ACh. Endothelium denuded aortic rings had also a marked hyporeactivity to PE. 4. In vivo administration of Ethyl-TU (0.1 mg kg-1 h-1, beginning 1 min after the onset of reperfusion) significantly increased survival time and rate, improved mean arterial blood pressure, restored the responsiveness to PE, but did not change MPO activity, leukopenia or the impairment in the responsiveness of aortic rings to ACh. Addition of Ethyl-TU (2 microM) to endothelium denuded aortic rings in vitro, restored the marked hyporeactivity to PE. Administration of the NO donor C87-3754 (0.75 mg kg-1 h-1, beginning 1 min after the onset of reperfusion) slightly increased survival time and reduced MPO activity and leukopenia, but did not change survival rate and mean arterial blood pressure. In addition C87

  13. The Nitric Oxide Synthase Inhibitor NG-Nitro-L-Arginine Methyl Ester Diminishes the Immunomodulatory Effects of Parental Arginine in Rats with Subacute Peritonitis.

    PubMed

    Lo, Hui-Chen; Hung, Ching-Yi; Huang, Fu-Huan; Su, Tzu-Cheng; Lee, Chien-Hsing

    2016-01-01

    The combined treatment of parenteral arginine and the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) have been shown to improve liver function and systemic inflammation in subacute peritonitic rats. Here, we investigated the effects of single and combined parenteral arginine and L-NAME treatments on leukocyte and splenocyte immunity. Male Wistar rats were subjected to cecal punctures and were intravenously given total parenteral nutrition solutions with or without arginine and/or L-NAME supplementations for 7 days. Non-surgical and sham-operated rats with no cecal puncture were given a chow diet and parenteral nutrition, respectively. Parenteral feeding elevated the white blood cell numbers and subacute peritonitis augmented the parenteral nutrition-induced alterations in the loss of body weight gain, splenomegaly, and splenocyte decreases. Parenteral arginine significantly increased the B-leukocyte level, decreased the natural killer T (NKT)-leukocyte and splenocyte levels, alleviated the loss in body weight gain and total and cytotoxic T-splenocyte levels, and attenuated the increases in plasma nitrate/nitrite and interferon-gamma production by T-splenocytes. L-NAME infusion significantly decreased NKT-leukocyte level, tumor-necrosis factor (TNF)-alpha production by T-splenocytes and macrophages, and interferon-gamma production by T-leukocytes, monocytes, and T-splenocytes, as well as increased interleukin-6 production by T-leukocytes and monocytes and nitrate/nitrite production by T-leukocytes. Combined treatment significantly decreased plasma nitrate/nitrite, the NKT-leukocyte level, and TNF-alpha production by T-splenocytes. Parenteral arginine may attenuate immune impairment and L-NAME infusion may augment leukocyte proinflammatory response, eliminate splenocyte proinflammatory and T-helper 1 responses, and diminish arginine-induced immunomodulation in combined treatment in subacute peritonitic rats. PMID:27007815

  14. The Nitric Oxide Synthase Inhibitor NG-Nitro-L-Arginine Methyl Ester Diminishes the Immunomodulatory Effects of Parental Arginine in Rats with Subacute Peritonitis

    PubMed Central

    Lo, Hui-Chen; Hung, Ching-Yi; Huang, Fu-Huan; Su, Tzu-Cheng; Lee, Chien-Hsing

    2016-01-01

    The combined treatment of parenteral arginine and the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME) have been shown to improve liver function and systemic inflammation in subacute peritonitic rats. Here, we investigated the effects of single and combined parenteral arginine and L-NAME treatments on leukocyte and splenocyte immunity. Male Wistar rats were subjected to cecal punctures and were intravenously given total parenteral nutrition solutions with or without arginine and/or L-NAME supplementations for 7 days. Non-surgical and sham-operated rats with no cecal puncture were given a chow diet and parenteral nutrition, respectively. Parenteral feeding elevated the white blood cell numbers and subacute peritonitis augmented the parenteral nutrition-induced alterations in the loss of body weight gain, splenomegaly, and splenocyte decreases. Parenteral arginine significantly increased the B-leukocyte level, decreased the natural killer T (NKT)-leukocyte and splenocyte levels, alleviated the loss in body weight gain and total and cytotoxic T-splenocyte levels, and attenuated the increases in plasma nitrate/nitrite and interferon-gamma production by T-splenocytes. L-NAME infusion significantly decreased NKT-leukocyte level, tumor-necrosis factor (TNF)-alpha production by T-splenocytes and macrophages, and interferon-gamma production by T-leukocytes, monocytes, and T-splenocytes, as well as increased interleukin-6 production by T-leukocytes and monocytes and nitrate/nitrite production by T-leukocytes. Combined treatment significantly decreased plasma nitrate/nitrite, the NKT-leukocyte level, and TNF-alpha production by T-splenocytes. Parenteral arginine may attenuate immune impairment and L-NAME infusion may augment leukocyte proinflammatory response, eliminate splenocyte proinflammatory and T-helper 1 responses, and diminish arginine-induced immunomodulation in combined treatment in subacute peritonitic rats. PMID:27007815

  15. Foscarnet, an inhibitor of the sodium-phosphate cotransporter NaPi-IIa, inhibits phosphorylation of glycogen synthase kinase-3β by lithium in the rat kidney cortex.

    PubMed

    Uwai, Yuichi; Kawasaki, Tatsuya; Nabekura, Tomohiro

    2016-06-01

    Lithium, which is used in the treatment of and prophylaxis for bipolar disease, inhibits glycogen synthase kinase-3β (GSK3β) by producing its phosphorylated form (p-GSK3β). GSK3β plays a role in apoptosis and some kinds of acute kidney injuries, and the formation of p-GSK3β is considered to contribute to protection against acute kidney injury. We previously reported that the sodium-phosphate cotransporter NaPi-IIa (SLC34A1) mediated the reabsorption of lithium in the rat kidney. In the present study, the phosphorylation status of GSK3β in the kidney cortex of rats administered lithium chloride and foscarnet, a typical inhibitor of NaPi-IIa, was examined using Western blotting. Under a 2-h infusion of lithium chloride, the plasma concentration of lithium was 1.06 mEq/l, and its renal clearance was calculated as 1.18 ml/min/kg, which was 29.6% of creatinine clearance. The abundance of p-GSK3β in the kidney cortex was augmented by the administration of lithium. The simultaneous infusion of foscarnet increased the renal clearance of lithium and its ratio to creatinine clearance as well as the urinary excretion of phosphate. Foscarnet also inhibited the lithium-induced phosphorylation of GSK3β. These results suggest that the reabsorption of lithium by NaPi-IIa triggers the phosphorylation of GSK3β in the rat kidney cortex. PMID:27238574

  16. A Screen for Extracellular Signal-Regulated Kinase-Primed Glycogen Synthase Kinase 3 Substrates Identifies the p53 Inhibitor iASPP

    PubMed Central

    Woodard, Crystal; Liao, Gangling; Goodwin, C. Rory; Hu, Jianfei; Xie, Zhi; dos Reis, Thaila F.; Newman, Rob; Rho, Heesool; Qian, Jiang

    2015-01-01

    ABSTRACT The Kaposi's sarcoma-associated herpesvirus (KSHV) LANA protein is essential for the replication and maintenance of virus genomes in latently KSHV-infected cells. LANA also drives dysregulated cell growth through a multiplicity of mechanisms that include altering the activity of the cellular kinases extracellular signal-regulated kinase (ERK) and glycogen synthase kinase 3 (GSK-3). To investigate the potential impact of these changes in enzyme activity, we used protein microarrays to identify cell proteins that were phosphorylated by the combination of ERK and GSK-3. The assays identified 58 potential ERK-primed GSK-3 substrates, of which 23 had evidence for in vivo phosphorylation in mass spectrometry databases. Two of these, SMAD4 and iASPP, were selected for further analysis and were confirmed as ERK-primed GSK-3 substrates. Cotransfection experiments revealed that iASPP, but not SMAD4, was targeted for degradation in the presence of GSK-3. iASPP interferes with apoptosis induced by p53 family members. To determine the importance of iASPP to KSHV-infected-cell growth, primary effusion lymphoma (PEL) cells were treated with an iASPP inhibitor in the presence or absence of the MDM2 inhibitor Nutlin-3. Drug inhibition of iASPP activity induced apoptosis in BC3 and BCBL1 PEL cells but did not induce poly(ADP-ribose) polymerase (PARP) cleavage in virus-negative BJAB cells. The effect of iASPP inhibition was additive with that of Nutlin-3. Interfering with iASPP function is therefore another mechanism that can sensitize KSHV-positive PEL cells to cell death. IMPORTANCE KSHV is associated with several malignancies, including primary effusion lymphoma (PEL). The KSHV-encoded LANA protein is multifunctional and promotes both cell growth and resistance to cell death. LANA is known to activate ERK and limit the activity of another kinase, GSK-3. To discover ways in which LANA manipulation of these two kinases might impact PEL cell survival, we screened a human

  17. The renal effects of the water-soluble, non-folylpolyglutamate synthetase-dependent thymidylate synthase inhibitor ZD9331 in mice.

    PubMed Central

    Walton, M. I.; Mitchell, F.; Aherne, G. W.; Medlow, C. J.; Boyle, F. T.; Jackman, A. L.

    1998-01-01

    ZD9331 is a novel, potent thymidylate synthase (TS) inhibitor which does not require polyglutamation by folylpolyglutamate synthetase (FPGS) for its activity. In contrast to Tomudex (ZD1694), ZD9331 may therefore be active against tumours with low FPGS activity. ZD9331 shows anti-tumour activity by both 24-h infusion and bolus administration in the murine thymidine kinase-deficient (TK -/-) lymphoma L5178Y. In view of the history of renal toxicity with some earlier TS inhibitors and the possible therapeutic use of bolus ZD9331, we have examined the effects of bolus ZD9331 dose and route of administration on plasma and kidney pharmacokinetics and renal function in mice. Renal function was assessed by measuring [14C]inulin clearance, and drug concentrations were assayed by reverse-phase high-performance liquid chromatography (HPLC). Renal function was unaffected by ZD9331 up to 150 mg kg(-1) either i.v. or i.p. However, at 200 mg kg(-1), glomerular filtration rate was significantly inhibited following i.v. but not i.p. administration. Pharmacokinetic studies showed that these effects were consistent with the markedly higher plasma drug concentrations occurring during early times following i.v. dosing, although the plasma drug profiles were otherwise similar for both routes. Kidney drug concentrations were slightly elevated in i.v.- versus i.p.-treated animals at the low dose (50 mg kg(-1)), with a correspondingly larger area under the curve. However, at the highest dose (200 mg kg(-1)), peak kidney drug concentrations were 20-fold higher following i.v. administration than after i.p., with marked kidney retention, resulting in a 50-fold greater kidney drug exposure for the i.v. versus the i.p. route. These data show that ZD9331 is non-nephrotoxic at active anti-tumour doses (50 mg kg(-1) i.p.) in mice, and only at very high bolus i.v. doses is there impaired renal function as a result of very high peak plasma concentrations. These adverse effects can be readily

  18. Specific action of the lipoxygenase pathway in mediating angiotensin II-induced aldosterone synthesis in isolated adrenal glomerulosa cells.

    PubMed Central

    Nadler, J L; Natarajan, R; Stern, N

    1987-01-01

    Angiotensin II (AII) in adrenal glomerulosa cells activates phospholipase C resulting in the formation of inositol phosphates and diacylglycerol rich in arachidonic acid (AA). Although glomerulosa cells can metabolize AA via cyclooxygenase (CO), this pathway plays little role in aldosterone synthesis. Recent evidence suggests that the lipoxygenase (LO) pathway may be important for hormonal secretion in endocrine tissues such as the islet of Langerhans. However, the capacity of the glomerulosa cell to synthesize LO products and their role in aldosterone secretion is not known. To study this, the effect of nonselective and selective LO inhibitors on AII, ACTH, and potassium-induced aldosterone secretion and LO product formation was evaluated in isolated rat glomerulosa cells. BW755c, a nonselective LO inhibitor dose dependently reduced the AII-stimulated level of aldosterone without altering AII binding (91 +/- 6 to 36 +/- 4 ng/10(6) cells/h 10(-4) M, P less than 0.001). The same effect was observed with another nonselective LO blocker, phenidone, and a more selective 12-LO inhibitor, Baicalein. In contrast U-60257, a selective 5-LO inhibitor did not change the AII-stimulated levels of aldosterone (208 +/- 11% control, AII 10(-9) M vs. 222 +/- 38%, AII + U-60257). The LO blockers action was specific for AII since neither BW755c nor phenidone altered ACTH or K+-induced aldosterone secretion. AII stimulated the formation of the 12-LO product 12-hydroxyeicosatetraenoic acid (12-HETE) as measured by ultraviolet detection and HPLC in AA loaded cells and by a specific RIA in unlabeled cells (501 +/- 50 to 990 +/- 10 pg/10(5) cells, P less than 0.02). BW755c prevented the AII-mediated rise in 12-HETE formation. In contrast, neither ACTH nor K+ increased 12-HETE levels. The addition of 12-HETE or its unstable precursor 12-HPETE (10(-9) or 10(-8) M) completely restored AII action during LO blockade. AII also produced an increase in 15-HETE formation, but the 15-LO products

  19. The Aldosterone Renin Ratio (ARR) APP as Tool to Enhance the Detection Rate of Primary Aldosteronism.

    PubMed

    Rossi, Gian Paolo; Bisogni, Valeria

    2016-06-01

    Primary aldosteronism is one of the most common forms of secondary hypertension, but it is often under diagnosed, which leads to the development of cardiovascular damage, and excess costs for long-term drug treatment and management of complications. The aldosterone to renin ratio (ARR) is a key step for early detection of primary aldosteronism, but unfortunately is not easily estimated. This is because plasma aldosterone and renin are measured with different assays, which provide results in different units of measure, with ensuing difficulty of obtaining the calculation of the ARR in the proper units and impossibility of interpreting results with reference to established cut off values. Therefore, doctors are often unable to draw unambiguous conclusions to be used for the clinical decision-making. To the aim of making the diagnostic work-up easier, we have developed an Application that provide a swift calculation of the ARR regardless of the units of measure used for plasma aldosterone and renin values. If the concomitant serum potassium level is available the App also provides the patient's probability of having an aldosterone-producing adenoma based on a validated logistic discriminant analysis. PMID:26883242

  20. Metoclopramide inhibits aldosterone biosynthesis in vitro.

    PubMed

    Lauer, C G; Braley, L M; Menachery, A I; Williams, G H

    1982-07-01

    Metoclopramide, a dopaminergic antagonist, has consistently elevated plasma aldosterone levels in vivo. To determine whether this was a direct action of metoclopramide on adrenal steroidogenesis, we examined the response of collagenase-dispersed rat adrenal glomerulosa cells to metoclopramide in vitro. The effect of increasing concentrations of metoclopramide (3 X 10(-10) to 3 X 10(-4) M) on basal as well as angiotensin II (2.4 X 10(-10) to 2.4 X 10(-8) M)-, ACTH (3.5 X 10(-11) M)- and potassium (5.9 meq/liter)-stimulated aldosterone production was evaluated. Metoclopramide caused a dose-related decrease in basal and stimulated aldosterone production (P less than 0.01). In addition, metoclopramide also blocked basal and stimulated corticosterone production (P less than 0.01). This was not due to an irreversible toxic effect, since glomerulosa cells preincubated with 3 X 10(-4) M metoclopramide excluded trypan blue dye and responded to ACTH stimulation. Sodium metabisulfite, an antioxidant present in the metoclopramide preparation, did not contribute to the metoclopramide effect. These results indicate that metoclopramide is an aldosterone antagonist in vitro, contrary to reported data obtained in vivo. Thus, metoclopramide may be a partial dopaminergic agonist: in vitro where dopamine levels are negligible, it is an agonist, whereas in vivo where dopamine concentrations are greater, it is an antagonist. PMID:6282568

  1. Inhibitors

    MedlinePlus

    ... Community Counts Blood Safety Inhibitors Articles & Key Findings Free Materials Videos Starting the Conversation Playing it Safe A Look at Hemophilia Joint Range of Motion My Story Links to Other Websites ...

  2. Fast Nongenomic Effect of Aldosterone on the Volume of Principal Cells in Collecting Tube and Genetic Heterogeneity of Epithelial Sodium Channel in the Postnatal Ontogenesis of Rat Kidney.

    PubMed

    Logvinenko, N S; Gerbek, Yu E; Solenov, E I; Ivanova, L N

    2016-03-01

    The effects of amiloride, epithelial sodium pump inhibitor, on the fast nongenomic effect of aldosterone in principal cells of an isolated segment of the distal portion of renal collecting tubes were studied in 10-day-old and adult rats. Fluorescent staining with Calcein AM showed various effects of amiloride (10(-5) M) on the stabilizing effect of aldosterone (10 nM) in hypotonic shock (280/140 mOsm/kg). Amiloride attenuated by 30% the effect of aldosterone on the amplitude of principal cell swelling in adult animals and almost completely abolished this effect in 10-day rats (p<0.05). These age-specific differences in the contribution of the distal portion of the collecting tube to the nongenomic effect of aldosterone did not depend on genetic heterogeneity of its α-subunit. PMID:27021081

  3. Upregulation of Steroidogenic Acute Regulatory Protein by Hypoxia Stimulates Aldosterone Synthesis in Pulmonary Artery Endothelial Cells to Promote Pulmonary Vascular Fibrosis

    PubMed Central

    Maron, Bradley A.; Oldham, William M.; Chan, Stephen Y.; Vargas, Sara O.; Arons, Elena; Zhang, Ying-Yi; Loscalzo, Joseph; Leopold, Jane A.

    2014-01-01

    Background The molecular mechanism(s) regulating hypoxia-induced vascular fibrosis are unresolved. Hyperaldosteronism correlates positively with vascular remodeling in pulmonary arterial hypertension (PAH), suggesting that aldosterone may contribute to the pulmonary vasculopathy of hypoxia. The hypoxia-sensitive transcription factors c-Fos/c-Jun regulate steroidogenic acute regulatory protein (StAR), which facilitates the rate-limiting step of aldosterone steroidogenesis. We hypothesized that c-Fos/c-Jun upregulation by hypoxia activates StAR-dependent aldosterone synthesis in human pulmonary artery endothelial cells (HPAECs) to promote vascular fibrosis in PAH. Methods and Results Patients with PAH, rats with Sugen/hypoxia-PAH, and mice exposed to chronic hypoxia expressed increased StAR in remodeled pulmonary arterioles, providing a basis for investigating hypoxia-StAR signaling in HPAECs. Hypoxia (2.0% FiO2) increased aldosterone levels selectively in HPAECs, which was confirmed by liquid chromatography-mass spectrometry. Increased aldosterone by hypoxia resulted from enhanced c-Fos/c-Jun binding to the proximal activator protein (AP-1) site of the StAR promoter in HPAECs, which increased StAR expression and activity. In HPAECs transfected with StAR-siRNA or treated with the AP-1 inhibitor, SR-11302, hypoxia failed to increase aldosterone, confirming that aldosterone biosynthesis required StAR activation by c-Fos/c-Jun. The functional consequences of aldosterone were confirmed by pharmacological inhibition of the mineralocorticoid receptor with spironolactone or eplerenone, which attenuated hypoxia-induced upregulation of the fibrogenic protein connective tissue growth factor and collagen III in vitro, and decreased pulmonary vascular fibrosis to improve pulmonary hypertension in Conclusions Our findings identify autonomous aldosterone synthesis in HPAECs due to hypoxia-mediated upregulation of StAR as a novel molecular mechanism that promotes pulmonary vascular

  4. CACNA1H(M1549V) Mutant Calcium Channel Causes Autonomous Aldosterone Production in HAC15 Cells and Is Inhibited by Mibefradil.

    PubMed

    Reimer, Esther N; Walenda, Gudrun; Seidel, Eric; Scholl, Ute I

    2016-08-01

    We recently demonstrated that a recurrent gain-of-function mutation in a T-type calcium channel, CACNA1H(M1549V), causes a novel Mendelian disorder featuring early-onset primary aldosteronism and hypertension. This variant was found independently in five families. CACNA1H(M1549V) leads to impaired channel inactivation and activation at more hyperpolarized potentials, inferred to cause increased calcium entry. We here aimed to study the effect of this variant on aldosterone production. We heterologously expressed empty vector, CACNA1H(WT) and CACNA1H(M1549V) in the aldosterone-producing adrenocortical cancer cell line H295R and its subclone HAC15. Transfection rates, expression levels, and subcellular distribution of the channel were similar between CACNA1H(WT) and CACNA1H(M1549V). We measured aldosterone production by an ELISA and CYP11B2 (aldosterone synthase) expression by real-time PCR. In unstimulated cells, transfection of CACNA1H(WT) led to a 2-fold increase in aldosterone levels compared with vector-transfected cells. Expression of CACNA1H(M1549V) caused a 7-fold increase in aldosterone levels. Treatment with angiotensin II or increased extracellular potassium levels further stimulated aldosterone production in both CACNA1H(WT)- and CACNA1H(M1549V)-transfected cells. Similar results were obtained for CYP11B2 expression. Inhibition of CACNA1H channels with the T-type calcium channel blocker Mibefradil completely abrogated the effects of CACNA1H(WT) and CACNA1H(M1549V) on CYP11B2 expression. These results directly link CACNA1H(M1549V) to increased aldosterone production. They suggest that calcium channel blockers may be beneficial in the treatment of a subset of patients with primary aldosteronism. Such blockers could target CACNA1H or both CACNA1H and the L-type calcium channel CACNA1D that is also expressed in the adrenal gland and mutated in patients with primary aldosteronism. PMID:27258646

  5. "Zipped Synthesis" by Cross-Metathesis Provides a Cystathionine β-Synthase Inhibitor that Attenuates Cellular H2S Levels and Reduces Neuronal Infarction in a Rat Ischemic Stroke Model.

    PubMed

    McCune, Christopher D; Chan, Su Jing; Beio, Matthew L; Shen, Weijun; Chung, Woo Jin; Szczesniak, Laura M; Chai, Chou; Koh, Shu Qing; Wong, Peter T-H; Berkowitz, David B

    2016-04-27

    The gaseous neuromodulator H2S is associated with neuronal cell death pursuant to cerebral ischemia. As cystathionine β-synthase (CBS) is the primary mediator of H2S biogenesis in the brain, it has emerged as a potential target for the treatment of stroke. Herein, a "zipped" approach by alkene cross-metathesis into CBS inhibitor candidate synthesis is demonstrated. The inhibitors are modeled after the pseudo-C 2-symmetric CBS product (l,l)-cystathionine. The "zipped" concept means only half of the inhibitor needs be constructed; the two halves are then fused by olefin cross-metathesis. Inhibitor design is also mechanism-based, exploiting the favorable kinetics associated with hydrazine-imine interchange as opposed to the usual imine-imine interchange. It is demonstrated that the most potent "zipped" inhibitor 6S reduces H2S production in SH-SY5Y cells overexpressing CBS, thereby reducing cell death. Most importantly, CBS inhibitor 6S dramatically reduces infarct volume (1 h post-stroke treatment; ∼70% reduction) in a rat transient middle cerebral artery occlusion model for ischemia. PMID:27163055

  6. “Zipped Synthesis” by Cross-Metathesis Provides a Cystathionine β-Synthase Inhibitor that Attenuates Cellular H2S Levels and Reduces Neuronal Infarction in a Rat Ischemic Stroke Model

    PubMed Central

    2016-01-01

    The gaseous neuromodulator H2S is associated with neuronal cell death pursuant to cerebral ischemia. As cystathionine β-synthase (CBS) is the primary mediator of H2S biogenesis in the brain, it has emerged as a potential target for the treatment of stroke. Herein, a “zipped” approach by alkene cross-metathesis into CBS inhibitor candidate synthesis is demonstrated. The inhibitors are modeled after the pseudo-C2-symmetric CBS product (l,l)-cystathionine. The “zipped” concept means only half of the inhibitor needs be constructed; the two halves are then fused by olefin cross-metathesis. Inhibitor design is also mechanism-based, exploiting the favorable kinetics associated with hydrazine-imine interchange as opposed to the usual imine–imine interchange. It is demonstrated that the most potent “zipped” inhibitor 6S reduces H2S production in SH-SY5Y cells overexpressing CBS, thereby reducing cell death. Most importantly, CBS inhibitor 6S dramatically reduces infarct volume (1 h post-stroke treatment; ∼70% reduction) in a rat transient middle cerebral artery occlusion model for ischemia. PMID:27163055

  7. 1400W, a highly selective inducible nitric oxide synthase inhibitor is a potential disease modifier in the rat kainate model of temporal lobe epilepsy.

    PubMed

    Puttachary, Sreekanth; Sharma, Shaunik; Verma, Saurabh; Yang, Yang; Putra, Marson; Thippeswamy, Achala; Luo, Diou; Thippeswamy, Thimmasettappa

    2016-09-01

    Status epilepticus (SE) initiates epileptogenesis to transform normal brain to epileptic state which is characterized by spontaneous recurrent seizures (SRS). Prior to SRS, progressive changes occur in the brain soon after SE, for example, loss of blood-brain barrier (BBB) integrity, neuronal hyper-excitability (epileptiform spiking), neuroinflammation [reactive gliosis, high levels of reactive oxygen/nitrogen species (ROS/RNS)], neurodegeneration and synaptic re-organization. Our hypothesis was that modification of early epileptogenic events will alter the course of disease development and its progression. We tested the hypothesis in the rat kainate model of chronic epilepsy using a novel disease modifying drug, 1400W, a highly selective inhibitor of inducible nitric oxide synthase (iNOS/NOS-II). In an in vitro mouse brain slice model, using a multi-electrode array system, co-application of 1400W with kainate significantly suppressed kainate-induced epileptiform spiking. In the rats, in vivo, 4h after the induction of SE with kainate, 1400W (20mg/kg, i.p.) was administered twice daily for three days to target early events of epileptogenesis. The rats were subjected to continuous (24/7) video-EEG monitoring, remotely, for six months from epidurally implanted cortical electrodes. The 1400W treatment significantly reduced the epileptiform spike rate during the first 12-74h post-SE, which resulted in >90% reduction in SRS in long-term during the six month period when compared to the vehicle-treated control group (257±113 versus 19±10 episodes). Immunohistochemistry (IHC) of brain sections at seven days and six months revealed a significant reduction in; reactive astrogliosis and microgliosis (M1 type), extravascular serum albumin (a marker for BBB leakage) and neurodegeneration in the hippocampus, amygdala and entorhinal cortex in the 1400W-treated rats when compared to the vehicle control. In the seven day group, hippocampal Western blots revealed downregulation of

  8. Nitric oxide donors prevent while the nitric oxide synthase inhibitor L-NAME increases arachidonic acid plus CYP2E1-dependent toxicity

    SciTech Connect

    Wu Defeng; Cederbaum, Arthur . E-mail: arthur.cederbaum@mssm.edu

    2006-10-15

    Polyunsaturated fatty acids such as arachidonic acid (AA) play an important role in alcohol-induced liver injury. AA promotes toxicity in rat hepatocytes with high levels of cytochrome P4502E1 and in HepG2 E47 cells which express CYP2E1. Nitric oxide (NO) participates in the regulation of various cell activities as well as in cytotoxic events. NO may act as a protectant against cytotoxic stress or may enhance cytotoxicity when produced at elevated concentrations. The goal of the current study was to evaluate the effect of endogenously or exogenously produced NO on AA toxicity in liver cells with high expression of CYP2E1 and assess possible mechanisms for its actions. Pyrazole-induced rat hepatocytes or HepG2 cells expressing CYP2E1 were treated with AA in the presence or absence of an inhibitor of nitric oxide synthase L-N {sup G}-Nitroarginine Methylester (L-NAME) or the NO donors S-nitroso-N-acetylpenicillamine (SNAP), and (Z)-1-[-(2-aminoethyl)-N-(2-aminoethyl)]diazen-1-ium-1,2-diolate (DETA-NONO). AA decreased cell viability from 100% to 48 {+-} 6% after treatment for 48 h. In the presence of L-NAME, viability was further lowered to 23 {+-} 5%, while, SNAP or DETA-NONO increased viability to 66 {+-} 8 or 71 {+-} 6%. The L-NAME potentiated toxicity was primarily necrotic in nature. L-NAME did not affect CYP2E1 activity or CYP2E1 content. SNAP significantly lowered CYP2E1 activity but not protein. AA treatment increased lipid peroxidation and lowered GSH levels. L-NAME potentiated while SNAP prevented these changes. Thus, L-NAME increased, while NO donors decreased AA-induced oxidative stress. Antioxidants prevented the L-NAME potentiation of AA toxicity. Damage to mitochondria by AA was shown by a decline in the mitochondrial membrane potential (MMP). L-NAME potentiated this decline in MMP in association with its increase in AA-induced oxidative stress and toxicity. NO donors decreased this decline in MMP in association with their decrease in AA

  9. Pulmonary hypertension triggered by lipopolysaccharide in ascites-susceptible and -resistant broilers is not amplified by aminoguanidine, a specific inhibitor of inducible nitric oxide synthase.

    PubMed

    Bowen, O T; Erf, G F; Anthony, N B; Wideman, R F

    2006-03-01

    Nitric oxide (NO) is a potent pulmonary vasodilator that modulates the pulmonary vasoconstriction and pulmonary hypertension (PH) triggered by bacterial lipopolysaccharide (LPS) in broilers. The amplitude and duration of the LPS-induced PH are markedly enhanced following pretreatment with N(omega)-nitro-L-arginine methyl ester (L-NAME), which inhibits NO synthesis by both the constitutive (endothelial) and inducible (inflammatory) forms of nitric oxide synthase (eNOS and iNOS, respectively). In the present study L-NAME and the selective iNOS inhibitor aminoguanidine (AG) were administered to differentiate between iNOS and eNOS as the primary source of NO that attenuates the pulmonary vascular response to LPS. Clinically healthy male progeny from ascites-susceptible and ascites-resistant lines were anesthetized, and their pulmonary artery was cannulated. The initial pulmonary arterial pressure (PAP) was recorded, then the broilers either remained untreated (control group) or were injected i.v. with AG. Ten minutes later all birds received an i.v. injection of LPS, followed 40 min later by an i.v. injection of L-NAME. When compared with untreated controls, AG neither increased the baseline PAP nor did it increase or prolong the PH response to LPS. The ascites-susceptible broilers maintained a higher PAP than the ascites-resistant broilers throughout the experiment, and the ascites-resistant broilers exhibited greater relative increases in PAP in response to LPS than did the ascites-susceptible broilers. Within 40 min after the LPS injection, PAP subsided to a level that did not differ from the respective preinjection value for each line. Injecting L-NAME reversed the decline in PAP, and within 5 min PAP returned to hypertensive levels approaching the maximum peak PH response to LPS. The absence of any impact of AG coupled with the profound response to L-NAME indicates that NO synthesized by eNOS rather than iNOS likely modulated the acute (within 1 h) PH elicited by

  10. Renin–angiotensin–aldosterone system (RAAS) pharmacogenomics: implications in heart failure management

    PubMed Central

    Beitelshees, Amber L.

    2016-01-01

    Blockade of the renin–angiotensin–aldosterone system (RAAS) with ACE inhibitors has been a cornerstone of heart failure therapy for over 15 years. More recently, further blockade of RAAS with aldosterone antagonists and angiotensin receptor blockers (ARBs) has been studied. While these therapies have certainly improved outcomes in the treatment of heart failure, morbidity and mortality remain extremely high. Furthermore, polypharmacy and complex regimens of seven medications on average is the norm for management of heart failure. This results in increased costs, patient burden, and uncertainty as to the best course of therapy. The ability to personalize patients’ therapeutic regimens using pharmacogenomics has the potential of providing more effective and efficient use of RAAS-modulating medications. This review highlights the implications of major RAAS pharmacogenetic studies, while outlining future directions for translation to practice. PMID:18351457

  11. From a natural product lead to the identification of potent and selective benzofuran-3-yl-(indol-3-yl)maleimides as glycogen synthase kinase 3beta inhibitors that suppress proliferation and survival of pancreatic cancer cells.

    PubMed

    Gaisina, Irina N; Gallier, Franck; Ougolkov, Andrei V; Kim, Ki H; Kurome, Toru; Guo, Songpo; Holzle, Denise; Luchini, Doris N; Blond, Sylvie Y; Billadeau, Daniel D; Kozikowski, Alan P

    2009-04-01

    Recent studies have demonstrated that glycogen synthase kinase 3beta (GSK-3beta) is overexpressed in human colon and pancreatic carcinomas, contributing to cancer cell proliferation and survival. Here, we report the design, synthesis, and biological evaluation of benzofuran-3-yl-(indol-3-yl)maleimides, potent GSK-3beta inhibitors. Some of these compounds show picomolar inhibitory activity toward GSK-3beta and an enhanced selectivity against cyclin-dependent kinase 2 (CDK-2). Selected GSK-3beta inhibitors were tested in the pancreatic cancer cell lines MiaPaCa-2, BXPC-3, and HupT3. We determined that some of these compounds, namely compounds 5, 6, 11, 20, and 26, demonstrate antiproliferative activity against some or all of the pancreatic cancer cells at low micromolar to nanomolar concentrations. We found that the treatment of pancreatic cancer cells with GSK-3beta inhibitors 5 and 26 resulted in suppression of GSK-3beta activity and a distinct decrease of the X-linked inhibitor of apoptosis (XIAP) expression, leading to significant apoptosis. The present data suggest a possible role for GSK-3beta inhibitors in cancer therapy, in addition to their more prominent applications in CNS disorders. PMID:19338355

  12. Epicardial Fat Thickness and Primary Aldosteronism.

    PubMed

    Iacobellis, G; Petramala, L; Marinelli, C; Calvieri, C; Zinnamosca, L; Concistrè, A; Iannucci, G; De Toma, G; Letizia, C

    2016-04-01

    Primary aldosteronism (PA) is associated with increased cardiovascular risk and left ventricle (LV) changes. Given its peculiar biomolecular and anatomic properties, excessive epicardial fat, the heart-specific visceral fat depot, can affect LV morphology. Whether epicardial fat can be associated with aldosterone and LV mass (LVM) in patients with PA is unknown. We performed ultrasound measurement of the epicardial fat thickness (EAT) in 79 consecutive newly diagnosed patients with PA, 59 affected by bilateral adrenal hyperplasia (IHA), 20 aldosterone-producing adenoma (APA), and 30 patients with essential hypertension (low renin hypertension) (EH). The 3 groups did not differ by age, sex distribution, body mass index (BMI), waist circumference (WC), or blood pressure values. EAT showed a trend of increase in both APA and IHA groups when compared to patients with EH (8.3±1.8 vs. 7.9±1.3 vs. 7.8±2 mm, respectively). EAT was significantly correlated with indexed LVM in the IHA group (r=0.35, p<005), better than BMI or WC were. Interestingly, EAT was highly associated with plasma aldosterone concentrations (PAC) and PAC/plasma renin activity (PRA) (PAC/PRA) in the APA group (p=0.58, p=0.37, p<0.01, for both), whereas BMI and WC were not. EAT was also correlated with PRA in the IHA group (p=-0.28, p<0.05). Our study indicates a novel and interesting interaction of EAT with PA, independent of obesity, abdominal fat and blood pressure control. EAT can locally affect LVM, at least in patients with IHA. Further studies in larger population will be required to confirm these findings. PMID:26983926

  13. Suppression of adrenal βarrestin1-dependent aldosterone production by ARBs: head-to-head comparison

    PubMed Central

    Dabul, Samalia; Bathgate-Siryk, Ashley; Valero, Thairy Reyes; Jafferjee, Malika; Sturchler, Emmanuel; McDonald, Patricia; Koch, Walter J.; Lymperopoulos, Anastasios

    2015-01-01

    The known angiotensin II (AngII) physiological effect of aldosterone synthesis and secretion is mediated by either Gq/11 proteins or βarrestin1 (βarr1), both of which can couple to its type 1 receptors (AT1Rs), present in adrenocortical zona glomerulosa (AZG) cell membranes. In the present study, we examined the relative potencies of all the currently used in the clinic AT1R antagonist drugs (angiotensin receptor blockers, ARBs, or sartans) at preventing activation of these two signaling mediators (G proteins and βarrs) at the AngII-bound AT1R and, consequently, at suppression of aldosterone in vitro. All ARBs were found to be potent inhibitors of G protein activation at the AT1R. However, candesartan and valsartan were the most potent at blocking AngII-induced βarr activation at this receptor, among the tetrazolo-biphenyl-methyl derivatives, translating into excellent efficacies at aldosterone suppression in H295R cells. Conversely, irbesartan and losartan were largely G protein-selective inhibitors at the AT1R, with very low potency towards βarr inhibition. As a result, they were very weak suppressors of βarr1-dependent aldosterone production in H295R cells. These findings provide important pharmacological insights into the drug class of ARBs and medicinal chemistry insights for future drug development in the field of AngII antagonism. PMID:25631300

  14. The Potential of ACTH in the Genesis of Primary Aldosteronism.

    PubMed

    Funder, John W

    2016-01-01

    Aldosterone is a homeostatic hormone, rising in volume depletion, sodium deficiency, and potassium loading, in response to angiotensin11 and elevation of plasma potassium. Pathophysiologically, in primary aldosteronism (PA) aldosterone levels are inappropriate for the patient's sodium and potassium status, and thus outside the normal feedback loop. ACTH is equivalent with A11 and [K(+)] in elevating aldosterone: its effects differ from those of the other secretagogues in four ways. First, it is not sustained; second, it raises aldosterone and cortisol secretion with equal potency; third, it is outside the normal feedback loops, reflecting the epithelial action of aldosterone; and finally its possible role in driving inappropriate aldosterone secretion (aka PA) is not widely recognized. Thirty years ago, it was shown that on a fixed sodium intake of 175 meq/day 36 of 100 unselected hypertensives, in whom PA has been excluded on contemporary criteria, had 24 h urinary aldosterone levels above the upper limit of normotensive controls. More recently, the dexamethasone enhanced fludrocortisone suppression test (FDST) showed 29% of unselected hypertensives to have plasma aldosterone concentrations above the upper limit of normotensive controls. In subjects negative for PA on the FDST, 27% were extremely hyper-responsive to ultra-low dose ACTH infusion; the remaining 73% showed minimal aldosterone elevation, as did normotensive controls: all three groups had negligible cortisol responses. On treadmill testing, no differences were found between groups in (minimally altered) ACTH and cortisol levels: hyper-responders to ultra-low ACTH, however, showed a major elevation in PAC. The implications of these studies, when validated, are substantial for PA, in that approximately half of hypertensive patients appear to show inappropriate aldosterone levels for their sodium status. The physiological role(s) of ACTH as an acute aldosterone secretagogue, and the mechanisms whereby

  15. The Potential of ACTH in the Genesis of Primary Aldosteronism

    PubMed Central

    Funder, John W.

    2016-01-01

    Aldosterone is a homeostatic hormone, rising in volume depletion, sodium deficiency, and potassium loading, in response to angiotensin11 and elevation of plasma potassium. Pathophysiologically, in primary aldosteronism (PA) aldosterone levels are inappropriate for the patient’s sodium and potassium status, and thus outside the normal feedback loop. ACTH is equivalent with A11 and [K+] in elevating aldosterone: its effects differ from those of the other secretagogues in four ways. First, it is not sustained; second, it raises aldosterone and cortisol secretion with equal potency; third, it is outside the normal feedback loops, reflecting the epithelial action of aldosterone; and finally its possible role in driving inappropriate aldosterone secretion (aka PA) is not widely recognized. Thirty years ago, it was shown that on a fixed sodium intake of 175 meq/day 36 of 100 unselected hypertensives, in whom PA has been excluded on contemporary criteria, had 24 h urinary aldosterone levels above the upper limit of normotensive controls. More recently, the dexamethasone enhanced fludrocortisone suppression test (FDST) showed 29% of unselected hypertensives to have plasma aldosterone concentrations above the upper limit of normotensive controls. In subjects negative for PA on the FDST, 27% were extremely hyper-responsive to ultra-low dose ACTH infusion; the remaining 73% showed minimal aldosterone elevation, as did normotensive controls: all three groups had negligible cortisol responses. On treadmill testing, no differences were found between groups in (minimally altered) ACTH and cortisol levels: hyper-responders to ultra-low ACTH, however, showed a major elevation in PAC. The implications of these studies, when validated, are substantial for PA, in that approximately half of hypertensive patients appear to show inappropriate aldosterone levels for their sodium status. The physiological role(s) of ACTH as an acute aldosterone secretagogue, and the mechanisms whereby

  16. Drug effects on aldosterone/plasma renin activity ratio in primary aldosteronism.

    PubMed

    Mulatero, Paolo; Rabbia, Franco; Milan, Alberto; Paglieri, Cristina; Morello, Fulvio; Chiandussi, Livio; Veglio, Franco

    2002-12-01

    Primary aldosteronism is a specifically treatable and potentially curable form of secondary hypertension. The aldosterone/plasma renin activity ratio (ARR) is routinely used as a screening test. Antihypertensive therapy can interfere with the interpretation of this parameter, but a correct washout period can be potentially harmful. We have investigated the effects of therapy with atenolol, amlodipine, doxazosin, fosinopril, and irbesartan on the ARR in a group of 230 patients with suspected primary aldosteronism. The percent change from control of ARR in patients taking amlodipine was -17%+/-32; atenolol, 62%+/-82; doxazosin, -5%+/-26; fosinopril, -30%+/-24; and irbesartan, -43%+/-27. The ARR change induced by atenolol was significantly higher compared with that induced by all other drugs (P<0.0001), and the ARR change induced by irbesartan was significantly lower than that induced by doxazosin (P<0.0001). One of 55 patients from the group taking amlodipine (1.8%) and 4/17 of the patients taking irbesartan (23.5%) gave a false-negative ARR (<50). None of the patients of the groups taking fosinopril, doxazosin, and atenolol displayed a false-negative ARR. Doxazosin and fosinopril can be used in hypertensive patients who need to undergo aldosterone and PRA measurement for the diagnosis of primary aldosteronism; amlodipine gave a very small percentage of false-negative diagnoses. beta-Blockers also do not interfere with the diagnosis of primary aldosteronism, but they can be responsible for an increased rate of false-positive ARRs. The high rate of false-negative diagnoses in patients undergoing irbesartan treatment requires confirmation in a higher number of patients. PMID:12468576

  17. Prenatal Testosterone Exposure Decreases Aldosterone Production but Maintains Normal Plasma Volume and Increases Blood Pressure in Adult Female Rats.

    PubMed

    More, Amar S; Mishra, Jay S; Hankins, Gary D; Kumar, Sathish

    2016-08-01

    Plasma testosterone levels are elevated in pregnant women with preeclampsia and polycystic ovaries; their offspring are at increased risk for hypertension during adult life. We tested the hypothesis that prenatal testosterone exposure induces dysregulation of the renin-angiotensin-aldosterone system, which is known to play an important role in water and electrolyte balance and blood pressure regulation. Female rats (6 mo old) prenatally exposed to testosterone were examined for adrenal expression of steroidogenic genes, telemetric blood pressure, blood volume and Na(+) and K(+) levels, plasma aldosterone, angiotensin II and vasopressin levels, and vascular responses to angiotensin II and arg(8)-vasopressin. The levels of Cyp11b2 (aldosterone synthase), but not the other adrenal steroidogenic genes, were decreased in testosterone females. Accordingly, plasma aldosterone levels were lower in testosterone females. Plasma volume and serum and urine Na(+) and K(+) levels were not significantly different between control and testosterone females; however, prenatal testosterone exposure significantly increased plasma vasopressin and angiotensin II levels and arterial pressure in adult females. In testosterone females, mesenteric artery contractile responses to angiotensin II were significantly greater, while contractile responses to vasopressin were unaffected. Angiotensin II type-1 receptor expression was increased, while angiotensin II type-2 receptor was decreased in testosterone arteries. These results suggest that prenatal testosterone exposure downregulates adrenal Cyp11b2 expression, leading to decreased plasma aldosterone levels. Elevated angiotensin II and vasopressin levels along with enhanced vascular responsiveness to angiotensin II may serve as an underlying mechanism to maintain plasma volume and Na(+) and K(+) levels and mediate hypertension in adult testosterone females. PMID:27385784

  18. Non-Bisphosphonate Inhibitors of Isoprenoid Biosynthesis Identified via Computer-Aided Drug Design

    PubMed Central

    Durrant, Jacob D; Cao, Rong; Gorfe, Alemayehu A; Zhu, Wei; Li, Jikun; Sankovsky, Anna; Oldfield, Eric; McCammon, J Andrew

    2011-01-01

    The relaxed complex scheme, a virtual-screening methodology that accounts for protein receptor flexibility, was used to identify a low-micromolar, non-bisphosphonate inhibitor of farnesyl diphosphate synthase. Serendipitously, we also found that several predicted farnesyl diphosphate synthase inhibitors were low-micromolar inhibitors of undecaprenyl diphosphate synthase. These results are of interest because farnesyl diphosphate synthase inhibitors are being pursued as both anti-infective and anticancer agents, and undecaprenyl diphosphate synthase inhibitors are antibacterial drug leads. PMID:21696546

  19. Identification of a Maleimide-Based Glycogen Synthase Kinase-3 (GSK-3) Inhibitor, BIP-135, That Prolongs the Median Survival Time of Δ7 SMA KO Mouse Model of Spinal Muscular Atrophy

    PubMed Central

    2011-01-01

    The discovery of upregulated glycogen synthase kinase-3 (GSK-3) in various pathological conditions has led to the development of a host of chemically diverse small molecule GSK-3 inhibitors, such as BIP-135. GSK-3 inhibition emerged as an alternative therapeutic target for treating spinal muscular atrophy (SMA) when a number of GSK-3 inhibitors were shown to elevate survival motor neuron (SMN) levels in vitro and to rescue motor neurons when their intrinsic SMN level was diminished by SMN-specific short hairpin RNA (shRNA). Despite their cellular potency, the in vivo efficacy of GSK-3 inhibitors has yet to be evaluated in an animal model of SMA. Herein, we disclose that a potent and reasonably selective GSK-3 inhibitor, namely BIP-135, was tested in a transgenic Δ7 SMA KO mouse model of SMA and found to prolong the median survival of these animals. In addition, this compound was shown to elevate the SMN protein level in SMA patient-derived fibroblast cells as determined by Western blot, and was neuroprotective in a cell-based, SMA-related model of oxidative stress-induced neurodegeneration. PMID:22348181

  20. Aldosterone induces active K+ secretion by enhancing mucosal expression of Kcnn4c and Kcnma1 channels in rat distal colon

    PubMed Central

    Singh, Satish K.; O'Hara, Bryan; Talukder, Jamilur R.

    2012-01-01

    Although both Kcnn4c and Kcnma1 channels are present on colonic mucosal membranes, only Kcnma1 has been suggested to mediate K+ secretion in the colon. Therefore, studies were initiated to investigate the relative roles of Kcnn4c and Kcnma1 in mediating aldosterone (Na-free diet)-induced K+ secretion. Mucosal to serosal (m-s), serosal to mucosal (s-m), and net 86Rb+ (K+ surrogate) fluxes as well as short circuit currents (Isc; measure of net ion movement) were measured under voltage clamp condition in rat distal colon. Active K+ absorption, but not K+ secretion, is present in normal, while aldosterone induces active K+ secretion (1.04 ± 0.26 vs. −1.21 ± 0.15 μeq·h−1·cm−2; P < 0.001) in rat distal colon. Mucosal VO4 (a P-type ATPase inhibitor) inhibited the net K+ absorption in normal, while it significantly enhanced net K+ secretion in aldosterone animals. The aldosterone-induced K+ secretion was inhibited by the mucosal addition of 1) either Ba2+ (a nonspecific K+ channel blocker) or charybdotoxin (CTX; a common Kcnn4 and Kcnma1 channel blocker) by 89%; 2) tetraethyl ammonium (TEA) or iberiotoxin (IbTX; a Kcnma1 channel blocker) by 64%; and 3) TRAM-34 (a Kcnn4 channel blocker) by 29%. TRAM-34, but not TEA, in the presence of IbTX further significantly inhibited the aldosterone-induced K+ secretion. Thus the aldosterone-induced Ba2+/CTX-sensitive K+ secretion consists of IbTX/TEA-sensitive (Kcnma1) and IbTX/TEA-insensitive fractions. TRAM-34 inhibition of the IbTX-insensitive fraction is consistent with the aldosterone-induced K+ secretion being mediated partially via Kcnn4c. Western and quantitative PCR analyses indicated that aldosterone enhanced both Kcnn4c and Kcnma1α protein expression and mRNA abundance. In vitro exposure of isolated normal colonic mucosa to aldosterone also enhanced Kcnn4c and Kcnma1α mRNA levels, and this was prevented by exposure to actinomycin D (an RNA synthesis inhibitor). These observations indicate that aldosterone

  1. Azilsartan, aliskiren, and combination antihypertensives utilizing renin-angiotensin-aldosterone system antagonists.

    PubMed

    Lanier, Gregg; Sankholkar, Kedar; Aronow, Wilbert S

    2014-01-01

    Health care providers managing hypertension (HTN) have a large selection of pharmacologic agents to choose from, including several different classes of drugs and many similar drugs within each class. Antagonism of the renin-angiotensin-aldosterone system has been shown to be very effective for HTN, especially in patients with cardiovascular disease, diabetes, and heart failure. Within this group, there have been 2 new agents recently introduced to the US market and approved by the Food and Drug Administration. It is important for the HTN specialist to be familiar with the merits of these 2 drugs: the angiotensin receptor blocker Edarbi (azilsartan) and the renin inhibitor Tekturna (aliskiren). Additionally, there have been several new, fixed-dose combination antihypertensives introduced to the market since 2006 that use a renin-angiotensin-aldosterone antagonist. Seven of these combine 2 drugs together in a single pill: Edarbyclor (azilsartan/chlorthalidone), Exforge (amlodipine/valsartan), Azor (olmesartan/amlodipine), Twynsta (amlodipine/telmisartan), Tekturna HCT [aliskiren/hydrochlorothiazide (HCTZ)], Valturna (aliskiren/valsartan), Tekamlo (aliskiren/amlodipine). Three triple-drug combination medications have also been introduced recently: Exforge HCT (amlodipine/valsartan/HCTZ), Tribenzor (olmesartan/amlodipine/HCTZ), and Amturnide (aliskiren/amlodipine/hydrocholorothiazide). This review will summarize the trial data and important pharmacologic merits of these 2 new renin-angiotensin-aldosterone antagonists and the advantages of initiating treatment with one of the new fixed-dose, combination drugs approved over the last 5 years. PMID:22975662

  2. Role of Nongenomic Signaling Pathways Activated by Aldosterone During Cardiac Reperfusion Injury.

    PubMed

    Ashton, Anthony W; Le, Thi Y L; Gomez-Sanchez, Celso E; Morel-Kopp, Marie-Christine; McWhinney, Brett; Hudson, Amanda; Mihailidou, Anastasia S

    2015-08-01

    Aldosterone (Aldo) activates both genomic and nongenomic signaling pathways in the cardiovascular system. Activation of genomic signaling pathways contributes to the adverse cardiac actions of Aldo during reperfusion injury; however, the extent nongenomic signaling pathways contribute has been difficult to identify due to lack of a specific ligand that activates only nongenomic signaling pathways. Using a pegylated aldosterone analog, aldosterone-3-carboxymethoxylamine-TFP ester conjugated to methoxypegylated amine (Aldo-PEG), we are able for the first time to distinguish between nongenomic and genomic cardiac actions of Aldo. We confirm Aldo-PEG activates phosphorylation of ERK1/2 in rat cardiomyocyte H9c2 cells similar to Aldo and G protein-coupled receptor 30 (GPR30 or GPER) agonist G1. GPER antagonist, G36, but not mineralocorticoid receptor (MR) antagonist spironolactone, prevented ERK1/2 phosphorylation by Aldo, Aldo-PEG, and G1. The selective nongenomic actions of Aldo-PEG are confirmed, with Aldo-PEG increasing superoxide production in H9c2 cells to similar levels as Aldo but having no effect on subcellular localization of MR. Striatin serves as a scaffold for GPER and MR, with GPER antagonist G36, but not spironolactone, restoring MR-striatin complexes. Aldo-PEG had no effect on MR-dependent transcriptional activation, whereas Aldo increased transcript levels of serum-regulated kinase 1 and plasminogen activator inhibitor-1. Using our ex vivo experimental rat model of myocardial infarction, we found aggravated infarct size and apoptosis by Aldo but not Aldo-PEG. Our studies confirm that in the heart, activation of nongenomic signaling pathways alone are not sufficient to trigger the deleterious effects of aldosterone during myocardial reperfusion injury. PMID:26121234

  3. Within-patient reproducibility of the aldosterone: renin ratio in primary aldosteronism.

    PubMed

    Rossi, Gian Paolo; Seccia, Teresa Maria; Palumbo, Gaetana; Belfiore, Anna; Bernini, Giampaolo; Caridi, Graziella; Desideri, Giovambattista; Fabris, Bruno; Ferri, Claudio; Giacchetti, Gilberta; Letizia, Claudio; Maccario, Mauro; Mallamaci, Francesca; Mannelli, Massimo; Patalano, Anna; Rizzoni, Damiano; Rossi, Ermanno; Pessina, Achille Cesare; Mantero, Franco

    2010-01-01

    The plasma aldosterone concentration:renin ratio (ARR) is widely used for the screening of primary aldosteronism, but its reproducibility is unknown. We, therefore, investigated the within-patient reproducibility of the ARR in a prospective multicenter study of consecutive hypertensive patients referred to specialized centers for hypertension in Italy. After the patients were carefully prepared from the pharmacological standpoint, the ARR was determined at baseline in 1136 patients and repeated after, on average, 4 weeks in the patients who had initially an ARR > or =40 and in 1 of every 4 of those with an ARR <40. The reproducibility of the ARR was assessed with Passing and Bablok and Deming regression, coefficient of reproducibility, and Bland-Altman and Mountain plots. Within-patient ARR comparison was available in 268 patients, of whom 49 had an aldosterone-producing adenoma, on the basis of the "4-corner criteria." The ARR showed a highly significant within-patient correlation (r=0.69; P<0.0001) and reproducibility. Bland-Altman plot showed no proportional, magnitude-related, or absolute systematic error between the ARR; moreover, only 7% of the values, for example, slightly more than what could be expected by chance, fell out of the 95% CI for the between-test difference. The accuracy of each ARR for pinpointing aldosterone-producing adenoma patients was approximately 80%. Thus, although it was performed under different conditions in a multicenter study, the ARR showed a good within-patient reproducibility. Hence, contrary to previously claimed poor reproducibility of the ARR, these data support its use for the screening of primary aldosteronism. PMID:19933925

  4. Inhibiting the neuronal isoform of nitric oxide synthase has similar effects on the compensatory choroidal and axial responses to myopic defocus in chicks as does the non-specific inhibitor L-NAME

    PubMed Central

    Nickla, Debora L.; Damyanova, Petya; Lytle, Grace

    2010-01-01

    In birds, the choroid plays a role in the visual regulation of eye growth, thickening in response to myopic defocus, and thinning in response to hyperopic defocus, in both cases moving the retina towards the image plane. This response is rapid, occurring within hours of the defocus stimulus. These changes are consistently associated with slower changes in the sclera, that result in the appropriate changes in axial elongation, decreasing growth in response to myopic defocus and increasing it in response to hyperopic defocus. The molecular mechanisms underlying the scleral response involve changes in the synthesis of extracellular matrix molecules, however, those underlying the changes in choroidal thickness are not known. However, evidence suggests that it may involve the gaseous signal molecule nitric oxide, as nitric oxide is a potent smooth muscle relaxant, and injections of the non-specific nitric oxide synthase inhibitor L-NAME transiently inhibits the thickening response. Interestingly, it also dis-inhibits ocular growth, in accordance with a mechanistic link between the two responses. If nitric oxide is part of the signal cascade underlying the visual regulation of eye growth, it would be important to ascertain the source of the molecule. As a first step towards doing so, we used various more specific NOS inhibitors and studied their effects on the choroidal and growth responses. Birds (7–12 days old) were fitted with +10 D lenses on one eye. On that day, single intravitreal injections (30 μl) of the following inhibitors were used: nNOS inhibitor N ω-propyl-L-arginine (n=12), iNOS inhibitor L-NIL (n=16), eNOS/iNOS inhibitor L-NIO (n=15), non-specific inhibitor L-NMMA (n=30) or physiological saline (n=18). Ocular dimensions were measured using high-frequency A-scan ultrasonography at the start of the experiment, and at 7, 24 and 48 hours after. We found that the nNOS inhibitor N ω-propyl-L-arginine had the same inhibitory effects on the choroidal response

  5. Triphenylethanamine Derivatives as Cholesteryl Ester Transfer Protein Inhibitors: Discovery of N-[(1R)-1-(3-Cyclopropoxy-4-fluorophenyl)-1-[3-fluoro-5-(1,1,2,2-tetrafluoroethoxy)phenyl]-2-phenylethyl]-4-fluoro-3-(trifluoromethyl)benzamide (BMS-795311).

    PubMed

    Qiao, Jennifer X; Wang, Tammy C; Adam, Leonard P; Chen, Alice Ye A; Taylor, David S; Yang, Richard Z; Zhuang, Shaobin; Sleph, Paul G; Li, Julia P; Li, Danshi; Yin, Xiaohong; Chang, Ming; Chen, Xue-Qing; Shen, Hong; Li, Jianqing; Smith, Daniel; Wu, Dauh-Rurng; Leith, Leslie; Harikrishnan, Lalgudi S; Kamau, Muthoni G; Miller, Michael M; Bilder, Donna; Rampulla, Richard; Li, Yi-Xin; Xu, Carrie; Lawrence, R Michael; Poss, Michael A; Levesque, Paul; Gordon, David A; Huang, Christine S; Finlay, Heather J; Wexler, Ruth R; Salvati, Mark E

    2015-11-25

    Cholesteryl ester transfer protein (CETP) inhibitors raise HDL-C in animals and humans and may be antiatherosclerotic by enhancing reverse cholesterol transport (RCT). In this article, we describe the lead optimization efforts resulting in the discovery of a series of triphenylethanamine (TPE) ureas and amides as potent and orally available CETP inhibitors. Compound 10g is a potent CETP inhibitor that maximally inhibited cholesteryl ester (CE) transfer activity at an oral dose of 1 mg/kg in human CETP/apoB-100 dual transgenic mice and increased HDL cholesterol content and size comparable to torcetrapib (1) in moderately-fat fed hamsters. In contrast to the off-target liabilities with 1, no blood pressure increase was observed with 10g in rat telemetry studies and no increase of aldosterone synthase (CYP11B2) was detected in H295R cells. On the basis of its preclinical profile, compound 10g was advanced into preclinical safety studies. PMID:26524347

  6. The past, present and future of renin–angiotensin aldosterone system inhibition☆

    PubMed Central

    Mentz, Robert J.; Bakris, George L.; Waeber, Bernard; McMurray, John J.V.; Gheorghiade, Mihai; Ruilope, Luis M.; Maggioni, Aldo P.; Swedberg, Karl; Piña, Ileana L.; Fiuzat, Mona; O’Connor, Christopher M.; Zannad, Faiez; Pitt, Bertram

    2014-01-01

    The renin–angiotensin aldosterone system (RAAS) is central to the pathogenesis of cardiovascular disease. RAAS inhibition can reduce blood pressure, prevent target organ damage in hypertension and diabetes, and improve outcomes in patients with heart failure and/or myocardial infarction. This review presents the history of RAAS inhibition including a summary of key heart failure, myocardial infarction, hypertension and atrial fibrillation trials. Recent developments in RAAS inhibition are discussed including implementation and optimization of current drug therapies. Finally, ongoing clinical trials, opportunities for future trials and issues related to the barriers and approvability of novel RAAS inhibitors are highlighted. PMID:23121914

  7. A useful tool to improve the case detection rate of primary aldosteronism: the aldosterone-renin ratio (ARR)-App.

    PubMed

    Rossi, Gian Paolo; Bisogni, Valeria

    2016-05-01

    The aldosterone-renin ratio is the most popular test for the case detection of primary aldosteronism, which entails the most common, albeit overlooked, form of endocrine secondary hypertension. A major hindrance to the clinical use of the aldosterone-renin ratio depends on the difficulty of achieving the calculation of this ratio, given that laboratories provide plasma aldosterone in different units of measurement, and renin is measured as plasma renin activity or direct active renin. We have therefore developed an App, which can be downloaded from the ESH website and the Apple store, to assist practising physicians in performing this calculation. Our hope is that this simple tool will help in increasing the detection rate of primary aldosteronism and ultimately the long-term cure of many hypertensive patients. PMID:26870884

  8. Hit Optimization of 5-Substituted-N-(piperidin-4-ylmethyl)-1H-indazole-3-carboxamides: Potent Glycogen Synthase Kinase-3 (GSK-3) Inhibitors with in Vivo Activity in Model of Mood Disorders.

    PubMed

    Furlotti, Guido; Alisi, Maria Alessandra; Cazzolla, Nicola; Dragone, Patrizia; Durando, Lucia; Magarò, Gabriele; Mancini, Francesca; Mangano, Giorgina; Ombrato, Rosella; Vitiello, Marco; Armirotti, Andrea; Capurro, Valeria; Lanfranco, Massimiliano; Ottonello, Giuliana; Summa, Maria; Reggiani, Angelo

    2015-11-25

    Novel treatments for bipolar disorder with improved efficacy and broader spectrum of activity are urgently needed. Glycogen synthase kinase 3β (GSK-3β) has been suggested to be a key player in the pathophysiology of bipolar disorder. A series of novel GSK-3β inhibitors having the common N-[(1-alkylpiperidin-4-yl)methyl]-1H-indazole-3-carboxamide scaffold were prepared taking advantage of an X-ray cocrystal structure of compound 5 with GSK-3β. We probed different substitutions at the indazole 5-position and at the piperidine-nitrogen to obtain potent ATP-competitive GSK-3β inhibitors with good cell activity. Among the compounds assessed in the in vivo PK experiments, 14i showed, after i.p. dosing, encouraging plasma PK profile and brain exposure, as well as efficacy in a mouse model of mania. Compound 14i was selected for further in vitro/in vivo pharmacological evaluation, in order to elucidate the use of ATP-competitive GSK-3β inhibitors as new tools in the development of new treatments for mood disorders. PMID:26486317

  9. Aldosterone receptor blockers spironolactone and canrenone: two multivalent drugs.

    PubMed

    Armanini, Decio; Sabbadin, Chiara; Donà, Gabriella; Clari, Giulio; Bordin, Luciana

    2014-05-01

    Canrenone is a derivative of spironolactone with lower antiandrogen activity. The drug is used only in few countries and can block all the side effects of aldosterone (ALDO). The drug is effective even in the presence of normal concentrations of ALDO. Mineralcorticoid receptor antagonists block the inflammatory activity of ALDO at the level of target tissues as heart, vessels and mononuclear leukocytes. Canrenone reduces the progression of insulin resistance and of microalbuminuria in type 2 diabetes and other related diseases. Both canrenone and hydrochlorothiazide can enhance the effect of treatment with ACE inhibitors and angiotensin II receptor blockers on microalbuminuria, but ALDO receptor blockers are more active. This different action is due to the fact that only canrenone blocks mineralocorticoid receptors. Serum potassium and renal function should be monitored before and during the treatment. ALDO receptor blockers are recommended in addition to polytherapy for resistant hypertension, but there are no studies on the effect of the drug as first-choice therapy. PMID:24617854

  10. Radiosynthesis and preliminary PET evaluation of glycogen synthase kinase 3β (GSK-3β) inhibitors containing [(11)C]methylsulfanyl, [(11)C]methylsulfinyl or [(11)C]methylsulfonyl groups.

    PubMed

    Kumata, Katsushi; Yui, Joji; Xie, Lin; Zhang, Yiding; Nengaki, Nobuki; Fujinaga, Masayuki; Yamasaki, Tomoteru; Shimoda, Yoko; Zhang, Ming-Rong

    2015-08-15

    Three compounds 1-3 containing methyl-sufanyl, sufinyl, or sulfonyl groups are strong inhibitors of glycogen synthase kinase 3β (GSK-3β), an enzyme associated with Alzheimer's disease. We labeled 1-3 with (11)C for a positron emission tomography (PET) brain imaging study. A novel thiophenol precursor 4 for radiosynthesis was prepared by reacting sulfoxide 2 with trifluoroacetic anhydride. [(11)C]1 was synthesized by reacting 4 with [(11)C]methyl iodide in 52 ± 5% radiochemical yield (n = 5, based on [(11)C]CO2, corrected for decay). Oxidation of [(11)C]1 with Oxone® produced [(11)C]2 and [(11)C]3, respectively. PET with [(11)C]1 and [(11)C]3 showed 2 fold higher brain uptake of radioactivity in a mouse model of cold water stress in which GSK-3β expression was increased, than in the controls. PMID:26067173

  11. ATP synthase.

    PubMed

    Junge, Wolfgang; Nelson, Nathan

    2015-01-01

    Oxygenic photosynthesis is the principal converter of sunlight into chemical energy. Cyanobacteria and plants provide aerobic life with oxygen, food, fuel, fibers, and platform chemicals. Four multisubunit membrane proteins are involved: photosystem I (PSI), photosystem II (PSII), cytochrome b6f (cyt b6f), and ATP synthase (FOF1). ATP synthase is likewise a key enzyme of cell respiration. Over three billion years, the basic machinery of oxygenic photosynthesis and respiration has been perfected to minimize wasteful reactions. The proton-driven ATP synthase is embedded in a proton tight-coupling membrane. It is composed of two rotary motors/generators, FO and F1, which do not slip against each other. The proton-driven FO and the ATP-synthesizing F1 are coupled via elastic torque transmission. Elastic transmission decouples the two motors in kinetic detail but keeps them perfectly coupled in thermodynamic equilibrium and (time-averaged) under steady turnover. Elastic transmission enables operation with different gear ratios in different organisms. PMID:25839341

  12. Renin and aldosterone at high altitude in man.

    PubMed

    Keynes, R J; Smith, G W; Slater, J D; Brown, M M; Brown, S E; Payne, N N; Jowett, T P; Monge, C C

    1982-01-01

    Measurements have been made of hormonal changes relevant to salt and water balance during prolonged exposure to hypoxia to improve our understanding of the syndrome of acute mountain sickness. We have attempted to delineate the detailed inter-relationships between the renin-aldosterone and the vasopressin systems by a metabolically controlled study, involving an orthostatic stress (45 degrees head-up tilt) and an injection of a standard dose of ACTH to test adrenal responsiveness. Three Caucasian medical students underwent a 7-day equilibration at 150 m (Lima, Peru), followed by a 6-day sojourn at 4350 m (Cerro de Pasco, Peru) and a final 7 days at 150 m. Measurements were made of sodium and potassium balance, body weight and the 24-h renal excretion of vasopressin, cortisol and aldosterone 18-glucuronide. These variables showed little change, except for that of aldosterone 18-glucuronide, which fell sharply at altitude and rebounded even more sharply on return to sea level. At altitude, basal plasma levels of renin activity and aldosterone fell, and the response to orthostasis was attenuated, but the fall of plasma renin activity, as compared to plasma aldosterone, was delayed; on return to sea level this dissociation was exacerbated with the return of normal renin responsiveness lagging behind that of aldosterone. We suggest that unknown factors which dissociate the orthodox renin-aldosterone relationship, other than the activity of the angiotensin I-converting enzyme, are operative on exposure to hypoxia. PMID:7057120

  13. Obesity, hypertension and aldosterone: is leptin the link?

    PubMed

    Xie, Ding; Bollag, Wendy B

    2016-07-01

    Obesity is a serious health hazard with rapidly increasing prevalence in the United States. In 2014, the World Health Organization estimated that nearly 2 billion people worldwide were overweight with an estimated 600 million of these obese. Obesity is associated with many chronic diseases, including cardiovascular disease and hypertension. Data from the Framingham Heart study suggest that approximately 78% of the risk for hypertension in men and 65% in women is related to excess body weight, a relationship that is further supported by studies showing increases in blood pressure with weight gain and decreases with weight loss. However, the exact mechanism by which excess body fat induces hypertension remains poorly understood. Several clinical studies have demonstrated elevated plasma aldosterone levels in obese individuals, especially those with visceral adiposity, with decreased aldosterone levels measured in concert with reduced blood pressure following weight loss. Since aldosterone is a mineralocorticoid hormone that regulates blood volume and pressure, serum aldosterone levels may link obesity and hypertension. Nevertheless, the mechanism by which obesity induces aldosterone production is unclear. A recent study by Belin de Chantemele and coworkers suggests that one adipose-released factor, leptin, is a direct agonist for aldosterone secretion; other adipose-related factors may also contribute to elevated aldosterone levels in obesity, such as very low-density lipoprotein (VLDL), the levels of which are elevated in obesity and which also directly stimulates aldosterone biosynthesis. This focused review explores the possible roles of leptin and VLDL in modulating aldosterone secretion to underlie obesity-associated hypertension. PMID:27252389

  14. Gonadotropin-Releasing Hormone Stimulate Aldosterone Production in a Subset of Aldosterone-Producing Adenoma

    PubMed Central

    Kishimoto, Rui; Oki, Kenji; Yoneda, Masayasu; Gomez-Sanchez, Celso E.; Ohno, Haruya; Kobuke, Kazuhiro; Itcho, Kiyotaka; Kohno, Nobuoki

    2016-01-01

    Abstract We aimed to detect novel genes associated with G protein-coupled receptors (GPCRs) in aldosterone-producing adenoma (APA) and elucidate the mechanisms underlying aldosterone production. Microarray analysis targeting GPCR-associated genes was conducted using APA without known mutations (APA-WT) samples (n = 3) and APA with the KCNJ5 mutation (APA-KCNJ5; n = 3). Since gonadotropin-releasing hormone receptor (GNRHR) was the highest expression in APA-WT by microarray analysis, we investigated the effect of gonadotropin-releasing hormone (GnRH) stimulation on aldosterone production. The quantitative polymerase chain reaction assay results revealed higher GNRHR expression levels in APA-WT samples those in APA-KCNJ5 samples (P < 0.05). LHCGR levels were also significantly elevated in APA-WT samples, and there was a significant and positive correlation between GNRHR and LHCGR expression in all APA samples (r = 0.476, P < 0.05). Patients with APA-WT (n = 9), which showed higher GNRHR and LHCGR levels, had significantly higher GnRH-stimulated aldosterone response than those with APA-KCNJ5 (n = 13) (P < 0.05). Multiple regression analysis revealed that the presence of the KCNJ5 mutation was linked to GNRHR mRNA expression (β = 0.94 and P < 0.01). HAC15 cells with KCNJ5 gene carrying T158A mutation exhibited a significantly lower GNRHR expression than that in control cells (P < 0.05). We clarified increased expression of GNRHR and LHCGR in APA-WT, and the molecular analysis including the receptor expression associated with clinical findings of GnRH stimulation. PMID:27196470

  15. Gonadotropin-Releasing Hormone Stimulate Aldosterone Production in a Subset of Aldosterone-Producing Adenoma.

    PubMed

    Kishimoto, Rui; Oki, Kenji; Yoneda, Masayasu; Gomez-Sanchez, Celso E; Ohno, Haruya; Kobuke, Kazuhiro; Itcho, Kiyotaka; Kohno, Nobuoki

    2016-05-01

    We aimed to detect novel genes associated with G protein-coupled receptors (GPCRs) in aldosterone-producing adenoma (APA) and elucidate the mechanisms underlying aldosterone production.Microarray analysis targeting GPCR-associated genes was conducted using APA without known mutations (APA-WT) samples (n = 3) and APA with the KCNJ5 mutation (APA-KCNJ5; n = 3). Since gonadotropin-releasing hormone receptor (GNRHR) was the highest expression in APA-WT by microarray analysis, we investigated the effect of gonadotropin-releasing hormone (GnRH) stimulation on aldosterone production.The quantitative polymerase chain reaction assay results revealed higher GNRHR expression levels in APA-WT samples those in APA-KCNJ5 samples (P < 0.05). LHCGR levels were also significantly elevated in APA-WT samples, and there was a significant and positive correlation between GNRHR and LHCGR expression in all APA samples (r = 0.476, P < 0.05). Patients with APA-WT (n = 9), which showed higher GNRHR and LHCGR levels, had significantly higher GnRH-stimulated aldosterone response than those with APA-KCNJ5 (n = 13) (P < 0.05). Multiple regression analysis revealed that the presence of the KCNJ5 mutation was linked to GNRHR mRNA expression (β = 0.94 and P < 0.01). HAC15 cells with KCNJ5 gene carrying T158A mutation exhibited a significantly lower GNRHR expression than that in control cells (P < 0.05).We clarified increased expression of GNRHR and LHCGR in APA-WT, and the molecular analysis including the receptor expression associated with clinical findings of GnRH stimulation. PMID:27196470

  16. [Inhibition of renin-angiotensin-aldosterone system in heart failure, or from CONSENSUS to PARADIGM-HF].

    PubMed

    Vítovec, Jiří; Špinar, Jindřich; Špinarová, Lenka

    2015-05-01

    An historical survey is presented of mortality trials on angiotensin-aldosteron system inhibition in patients with chronic heart failure. From the CONSENSUS trial up to the PARADIGM-HF trial, ACE inhibitors/angiotensin II receptor antagonists (AT1-blockers, ARBs, sartans), along with mineralocorticoid receptor blockers, have been the gold standard of treatment. Both direct renin blocker aliskiren and dual blocker enalapril + neprilysin proved ineffective; on the other hand, the new dual inhibitor valsartan + neprilysin LCZ 696 is a new and promising therapeutic agent for future treatment of chronic heart failure. PMID:26075858

  17. History of aldosterone on its 50th birthday.

    PubMed

    Fiore, Cristina; Calò, Lorenzo A; Colombo, Lorenzo; Grimm, Clarence E; Armanini, Decio

    2006-01-01

    The paper describes the impact of mineralocorticoid substances on water regulation from Theophrastus (IV century B.C.) to Thomas Addison (1849). It also opens to the missed discovery of aldosterone of I.A. Macchi. PMID:16874725

  18. Global and Renal-Specific Sympathoinhibition in Aldosterone Hypertension

    PubMed Central

    Lohmeier, Thomas E.; Liu, Boshen; Hildebrandt, Drew A.; Cates, Adam W.; Georgakopoulos, Dimitrios; Irwin, Eric D.

    2015-01-01

    Recent technology for chronic electrical activation of the carotid baroreflex and renal nerve ablation provide global and renal-specific suppression of sympathetic activity, respectively, but the conditions for favorable antihypertensive responses in resistant hypertension are unclear. Because inappropriately high plasma levels of aldosterone are prevalent in these patients, we investigated the effects of baroreflex activation and surgical renal denervation in dogs with hypertension induced by chronic infusion of aldosterone (12µg/kg/day). Under control conditions, basal values for mean arterial pressure and plasma norepinephrine concentration were 100±3 mm Hg and 134±26 pg/mL, respectively. By day 7 of baroreflex activation, plasma norepinephrine was reduced by ~ 40% and arterial pressure by 16±2 mmHg. All values returned to control levels during the recovery period. Arterial pressure increased to 122±5 mm Hg concomitant with a rise in plasma aldosterone concentration from 4.3±0.4 to 70.0±6.4 ng/dL after 14 days of aldosterone infusion, with no significant effect on plasma norepinephrine. After 7 days of baroreflex activation at control stimulation parameters, the reduction in plasma norepinephrine was similar but the fall in arterial pressure (7±1 mmHg) was diminished (~ 55%) during aldosterone hypertension as compared to control conditions. Despite sustained suppression of sympathetic activity, baroreflex activation did not have central actions to inhibit either the stimulation of vasopressin secretion or drinking induced by increased plasma osmolality during chronic aldosterone infusion. Finally, renal denervation did not attenuate aldosterone hypertension. These findings suggest that aldosterone excess may portend diminished blood pressure lowering to global and especially renal-specific sympathoinhibition during device-based therapy. PMID:25895584

  19. Global- and renal-specific sympathoinhibition in aldosterone hypertension.

    PubMed

    Lohmeier, Thomas E; Liu, Boshen; Hildebrandt, Drew A; Cates, Adam W; Georgakopoulos, Dimitrios; Irwin, Eric D

    2015-06-01

    Recent technology for chronic electric activation of the carotid baroreflex and renal nerve ablation provide global and renal-specific suppression of sympathetic activity, respectively, but the conditions for favorable antihypertensive responses in resistant hypertension are unclear. Because inappropriately high plasma levels of aldosterone are prevalent in these patients, we investigated the effects of baroreflex activation and surgical renal denervation in dogs with hypertension induced by chronic infusion of aldosterone (12 μg/kg per day). Under control conditions, basal values for mean arterial pressure and plasma norepinephrine concentration were 100±3 mm Hg and 134±26 pg/mL, respectively. By day 7 of baroreflex activation, plasma norepinephrine was reduced by ≈40% and arterial pressure by 16±2 mm Hg. All values returned to control levels during the recovery period. Arterial pressure increased to 122±5 mm Hg concomitant with a rise in plasma aldosterone concentration from 4.3±0.4 to 70.0±6.4 ng/dL after 14 days of aldosterone infusion, with no significant effect on plasma norepinephrine. After 7 days of baroreflex activation at control stimulation parameters, the reduction in plasma norepinephrine was similar but the fall in arterial pressure (7±1 mm Hg) was diminished (≈55%) during aldosterone hypertension when compared with control conditions. Despite sustained suppression of sympathetic activity, baroreflex activation did not have central actions to inhibit either the stimulation of vasopressin secretion or drinking induced by increased plasma osmolality during chronic aldosterone infusion. Finally, renal denervation did not attenuate aldosterone hypertension. These findings suggest that aldosterone excess may portend diminished blood pressure lowering to global and especially renal-specific sympathoinhibition during device-based therapy. PMID:25895584

  20. Inducible nitric oxide synthase and inflammation.

    PubMed

    Salvemini, D; Marino, M H

    1998-01-01

    Nitric oxide (NO), derived from L-arginine (L-Arg) by the enzyme nitric oxide synthase (NOS), is involved in acute and chronic inflammatory events. In view of the complexity associated with the inflammatory response, the dissection of possible mechanisms by which NO modulates this response will be profitable in designing novel and more efficacious NOS inhibitors. In this review we describe the consequences associated with the induction of inducible nitric oxide synthase (iNOS) and its therapeutic implications. PMID:15991919

  1. Effects of aldosterone on insulin sensitivity and secretion

    PubMed Central

    Luther, James M.

    2014-01-01

    Dr. Conn originally reported an increased risk of diabetes in patients with hyperaldosteronism in the 1950’s, although the mechanism remains unclear. Aldosterone-induced hypokalemia was initially described to impair glucose tolerance by impairing insulin secretion. Correction of hypokalemia by potassium supplementation only partially restored insulin secretion and glucose tolerance, however. Aldosterone also impairs glucose-stimulated insulin secretion in isolated pancreatic islets via reactive oxygen species in a mineralocorticoid receptor-independent manner. Aldosterone-induced mineralocorticoid receptor activation also impairs insulin sensitivity in adipocytes and skeletal muscle. Aldosterone may produce insulin resistance secondarily by altering potassium, increasing inflammatory cytokines, and reducing beneficial adipokines such as adiponectin. Renin-angiotensin system antagonists reduce circulating aldosterone concentrations and also the risk of type 2 diabetes in clinical trials. These data suggest that primary and secondary hyperaldosteronism may contribute to worsening glucose tolerance by impairing insulin sensitivity or insulin secretion in humans. Future studies should define the effects of MR antagonists and aldosterone on insulin secretion and sensitivity in humans. PMID:25194457

  2. Evaluation of aldosterone excretion in very low birth weight infants.

    PubMed

    Abdel Mohsen, Abdel Hakeem; Taha, Gamal; Kamel, Bothina A; Maksood, Mohamed Abdel

    2016-01-01

    Data about aldosterone production and excretion in the neonatal period are still few and controversial. Our objectives are to assess urinary aldosterone excretion (UAE) in very low birth weight (VLBW) infants and to identify clinical and biochemical variables that may influence this excretion. Thirty VLBW infants (14 males and 16 females), their gestational age <32 weeks and body weight <1500 g, were included in the study. Demographic and clinical data were recorded, within the first 72 h of life and urine and blood samples were collected for the measurement of urinary aldosterone and serum potassium, sodium, and chloride. The mean UAE value was 0.176 ± 0.05 μg/24 h and the mean absolute UAE was 1906 ± 271 pg/mL. There was a statistically significant positive correlation between UAE and gestational age and birth weight; also, infants with respiratory distress syndrome had higher urinary aldosterone levels than infants without respiratory distress. Only plasma sodium was a significant independent factor that negatively influenced UAE on linear regression analysis. The renin-angiotensin-aldosterone system of VLBW infants seems to be able, even immediately after birth, to respond to variations of plasma sodium concentrations; measurement of UAE constitutes an interesting method to determine aldosterone production in VLBW infants. PMID:27424689

  3. The metabolism and secretion of aldosterone in elderly subjects.

    PubMed

    Flood, C; Gherondache, C; Pincus, G; Tait, J F; Tait, S A; Willoughby, S

    1967-06-01

    The secretion rates [34 +/- 6 (SE) mug per day, 9 subjects] and metabolic clearance rates (MCR) [1,288 +/- 120 (SE) L of plasma per day, 9 subjects] of aldosterone in elderly subjects are significantly lower than those of young subjects [77 +/- 7 (SE) mug per day and 1,631 +/- 106 (SE) L per day, respectively]. There is a correlation of the MCR and secretion rate values (p = 0.02), but the calculated plasma concentrations (secretion rate/MCR) are also significantly low in the elderly subjects [2.6 +/- 0.3 (SE) compared with concentrations in the plasma from young subjects of 4.7 +/- 0.6 (SE) mug per 100 ml plasma]. The urinary excretion of radioactivity from oral and intravenously administered labeled aldosterone as aldosterone in the neutral extract, as aldosterone released by acid hydrolysis, and as tetrahydroaldosterone released by incubation with beta-glucuronidase is generally similar for young and elderly subjects except that a larger portion of the oral compared with the intravenous dose is excreted as free aldosterone in the elderly subjects, indicating that the splanchnic extraction is reduced. The calculated splanchnic blood flow (assuming no alteration in extrasplanchnic metabolism) is also slightly lowered. Therefore, as in patients with mild cardiac dysfunction, the lowered MCR of subjects is due to both reduced splanchnic extraction and blood flow. However, unlike the heart failure patients, in the elderly subjects the plasma concentration of aldosterone is also reduced. PMID:6026101

  4. Adrenal Venous Sampling: Where Is the Aldosterone Disappearing to?

    SciTech Connect

    Solar, Miroslav; Ceral, Jiri; Krajina, Antonin; Ballon, Marek; Malirova, Eva; Brodak, Milos; Cap, Jan

    2010-08-15

    Adrenal venous sampling (AVS) is generally considered to be the gold standard in distinguishing unilateral and bilateral aldosterone hypersecretion in primary hyperaldosteronism. However, during AVS, we noticed a considerable variability in aldosterone concentrations among samples thought to have come from the right adrenal glands. Some aldosterone concentrations in these samples were even lower than in samples from the inferior vena cava. We hypothesized that the samples with low aldosterone levels were unintentionally taken not from the right adrenal gland, but from hepatic veins. Therefore, we sought to analyze the impact of unintentional cannulation of hepatic veins on AVS. Thirty consecutive patients referred for AVS were enrolled. Hepatic vein sampling was implemented in our standardized AVS protocol. The data were collected and analyzed prospectively. AVS was successful in 27 patients (90%), and hepatic vein cannulation was successful in all procedures performed. Cortisol concentrations were not significantly different between the hepatic vein and inferior vena cava samples, but aldosterone concentrations from hepatic venous blood (median, 17 pmol/l; range, 40-860 pmol/l) were markedly lower than in samples from the inferior vena cava (median, 860 pmol/l; range, 460-4510 pmol/l). The observed difference was statistically significant (P < 0.001). Aldosterone concentrations in the hepatic veins are significantly lower than in venous blood taken from the inferior vena cava. This finding is important for AVS because hepatic veins can easily be mistaken for adrenal veins as a result of their close anatomic proximity.

  5. Optimal antagonism of the Renin-Angiotensin-aldosterone system: do we need dual or triple therapy?

    PubMed

    Werner, Christian; Pöss, Janine; Böhm, Michael

    2010-07-01

    The cardiovascular and cardiorenal disease continuum comprises the transition from cardiovascular risk factors to endothelial dysfunction and atherosclerosis, to clinical complications such as myocardial infarction (MI) and stroke, to the development of persistent target-organ damage and, ultimately, to chronic congestive heart failure (CHF), end-stage renal disease or premature death. The renin-angiotensin-aldosterone system (RAAS) is involved in all steps along this pathway, and RAAS blockade with ACE inhibitors or angiotensin AT(1)-receptor antagonists (angiotensin receptor blockers; ARBs) has turned out to be beneficial for patient outcomes throughout the disease continuum. Both ACE inhibitors and ARBs can prevent or reverse endothelial dysfunction and atherosclerosis, thereby reducing the risk of cardiovascular events. These drugs have further been shown to reduce end-organ damage in the heart, kidneys and brain. Aldosterone antagonists such as spironolactone and eplerenone are increasingly recognized as a third class of RAAS inhibitor with potent risk-reducing properties, especially but not solely with respect to the inhibition of cardiac remodelling and the possible prevention of heart failure. In secondary prevention, head-to-head comparisons of ACE inhibitors and ARBs, such as the recent ONTARGET study, provided evidence that, in addition to better tolerability, ARBs are non-inferior to ACE inhibitors in the prevention of clinical endpoints such as MI and stroke in cardiovascular high-risk patients. However, the combination of both ramipril and telmisartan at the maximally tolerated dosage achieved no further benefits and was associated with more adverse events such as symptomatic hypotension and renal dysfunction. In acute MI complicated by heart failure, the VALIANT trial has shown similar effects of ACE inhibition with captopril and ARB treatment with valsartan, but dual RAAS blockade did not further reduce events. In CHF, meta-analyses of RESOLVD, Val

  6. Impact of Aldosterone-Producing Adenoma on Endothelial Function and Rho-Associated Kinase Activity in Patients With Primary Aldosteronism

    PubMed Central

    Matsumoto, Takeshi; Oki, Kenji; Kajikawa, Masato; Nakashima, Ayumu; Maruhashi, Tatsuya; Iwamoto, Yumiko; Iwamoto, Akimichi; Oda, Nozomu; Hidaka, Takayuki; Kihara, Yasuki; Kohno, Nobuoki; Chayama, Kazuaki; Goto, Chikara; Aibara, Yoshiki; Noma, Kensuke; Liao, James K.; Higashi, Yukihito

    2016-01-01

    The purpose of this study was to evaluate vascular function and activity of Rho-associated kinases in patients with primary aldosteronism. Vascular function, including flow-mediated vasodilation and nitroglycerine-induced vasodilation, and Rho-associated kinase activity in peripheral leukocytes were evaluated in 21 patients with aldosterone-producing adenoma, 23 patients with idiopathic hyperaldosteronism, and 40 age-, gender-, and blood pressure-matched patients with essential hypertension. Flow-mediated vasodilation was significantly lower in the aldosterone-producing adenoma group than in the idiopathic hyperaldosteronism and essential hypertension groups (3.2±2.0% vs. 4.6±2.3% and 4.4±2.2%, P<0.05, respectively), whereas there was no significant difference in flow-mediated vasodilation between the idiopathic hyperaldosteronism and essential hypertension groups. There was no significant difference in nitroglycerine-induced vasodilation in the three groups. Rho-associated kinase activity was higher in the aldosterone-producing adenoma group than in the idiopathic hyperaldosteronism and essential hypertension groups (1.29±0.57 vs. 1.00±0.46 and 0.81±0.36, P<0.05, respectively), whereas there was no significant difference in Rho-associated kinase activity between the idiopathic hyperaldosteronism and essential hypertension groups. Flow-mediated vasodilation correlated with age (r=−0.31, P<0.01), plasma aldosterone concentration (r=−0.35, P<0.01) and aldosterone to renin ratio (r=−0.34, P<0.01). Rho-associated kinase activity correlated with age (r=−0.24, P=0.04), plasma aldosterone concentration (r=0.33, P<0.01) and aldosterone to renin ratio (r=0.46, P<0.01). After adrenalectomy, flow-mediated vasodilation and Rho-associated kinase activity were restored in aldosterone-producing adenoma patients. Aldosterone-producing adenoma was associated with both endothelial dysfunction and increased Rho-associated kinase activity compared with those in

  7. Somatic and germline CACNA1D calcium channel mutations in aldosterone-producing adenomas and primary aldosteronism

    PubMed Central

    Scholl, Ute I.; Goh, Gerald; Stölting, Gabriel; de Oliveira, Regina Campos; Choi, Murim; Overton, John D.; Fonseca, Annabelle L.; Korah, Reju; Starker, Lee F.; Kunstman, John W.; Prasad, Manju L.; Hartung, Erum A.; Mauras, Nelly; Benson, Matthew R.; Brady, Tammy; Shapiro, Jay R.; Loring, Erin; Nelson-Williams, Carol; Libutti, Steven K.; Mane, Shrikant; Hellman, Per; Westin, Gunnar; Åkerström, Göran; Björklund, Peyman; Carling, Tobias; Fahlke, Christoph; Hidalgo, Patricia; Lifton, Richard P.

    2013-01-01

    Adrenal aldosterone-producing adenomas (APAs) constitutively produce the salt-retaining hormone aldosterone and are a common cause of severe hypertension. Recurrent mutations in the potassium channel KCNJ5 that result in cell depolarization and Ca2+ influx cause ~40% of these tumors1. We found five somatic mutations (four altering glycine 403, one altering isoleucine 770) in CACNA1D, encoding a voltage-gated calcium channel, among 43 non-KCNJ5-mutant APAs. These mutations lie in S6 segments that line the channel pore. Both result in channel activation at less depolarized potentials, and glycine 403 mutations also impair channel inactivation. These effects are inferred to cause increased Ca2+ influx, the sufficient stimulus for aldosterone production and cell proliferation in adrenal glomerulosa2. Remarkably, we identified de novo mutations at the identical positions in two children with a previously undescribed syndrome featuring primary aldosteronism and neuromuscular abnormalities. These findings implicate gain of function Ca2+ channel mutations in aldosterone-producing adenomas and primary aldosteronism. PMID:23913001

  8. Dual Blockade of the Renin-angiotensin-aldosterone System in Type 2 Diabetic Kidney Disease

    PubMed Central

    Feng, Yan-Huan; Fu, Ping

    2016-01-01

    Objective: To examine the efficacy and safety of dual blockade of the renin-angiotensin-aldosterone system (RAAS) among patients with type 2 diabetic kidney disease. Data Sources: We searched the major literature repositories, including the Cochrane Central Register of Controlled Trials, MEDLINE and EMBASE, for randomized clinical trials published between January 1990 and October 2015 that compared the efficacy and safety of the use of dual blockade of the RAAS versus the use of monotherapy, without applying any language restrictions. Keywords for the searches included “diabetic nephropathy,” “chronic kidney disease,” “chronic renal insufficiency,” “diabetes mellitus,” “dual therapy,” “combined therapy,” “dual blockade,” “renin-angiotensin system,” “angiotensin-converting enzyme inhibitor,” “angiotensin-receptor blocker,” “aldosterone blockade,” “selective aldosterone blockade,” “renin inhibitor,” “direct renin inhibitor,” “mineralocorticoid receptor blocker,” etc. Study Selection: The selected articles were carefully reviewed. We excluded randomized clinical trials in which the kidney damage of patients was related to diseases other than diabetes mellitus. Results: Combination treatment with an angiotensin-converting enzyme inhibitor supplemented by an angiotensin II receptor blocking agent is expected to provide a more complete blockade of the RAAS and a better control of hypertension. However, existing literature has presented mixed results, in particular, related to patient safety. In view of this, we conducted a comprehensive literature review in order to explain the rationale for dual blockade of the RAAS, and to discuss the pros and cons. Conclusions: Despite the negative results of some recent large-scale studies, it may be immature to declare that the dual blockade is a failure because of the complex nature of the RAAS surrounding its diversified functions and utility. Further trials are warranted

  9. Tetra- and pentacyclic triterpene acids from the ancient anti-inflammatory remedy frankincense as inhibitors of microsomal prostaglandin E(2) synthase-1.

    PubMed

    Verhoff, Moritz; Seitz, Stefanie; Paul, Michael; Noha, Stefan M; Jauch, Johann; Schuster, Daniela; Werz, Oliver

    2014-06-27

    The microsomal prostaglandin E2 synthase (mPGES)-1 is the terminal enzyme in the biosynthesis of prostaglandin (PG)E2 from cyclooxygenase (COX)-derived PGH2. We previously found that mPGES-1 is inhibited by boswellic acids (IC50 = 3-30 μM), which are bioactive triterpene acids present in the anti-inflammatory remedy frankincense. Here we show that besides boswellic acids, additional known triterpene acids (i.e., tircuallic, lupeolic, and roburic acids) isolated from frankincense suppress mPGES-1 with increased potencies. In particular, 3α-acetoxy-8,24-dienetirucallic acid (6) and 3α-acetoxy-7,24-dienetirucallic acid (10) inhibited mPGES-1 activity in a cell-free assay with IC50 = 0.4 μM, each. Structure-activity relationship studies and docking simulations revealed concrete structure-related interactions with mPGES-1 and its cosubstrate glutathione. COX-1 and -2 were hardly affected by the triterpene acids (IC50 > 10 μM). Given the crucial role of mPGES-1 in inflammation and the abundance of highly active triterpene acids in frankincence extracts, our findings provide further evidence of the anti-inflammatory potential of frankincense preparations and reveal novel, potent bioactivities of tirucallic acids, roburic acids, and lupeolic acids. PMID:24844534

  10. Development of a Medium-Throughput Targeted LCMS Assay to Detect Endogenous Cellular Levels of Malonyl-CoA to Screen Fatty Acid Synthase Inhibitors.

    PubMed

    Hopcroft, Philip J; Fisher, David I

    2016-02-01

    The fatty acid synthase (FAS) enzyme in mammalian cells is a large multidomain protein responsible for de novo synthesis of fatty acids. The steps catalyzed by FAS involve the condensation of acetyl-CoA and malonyl-CoA moieties in the presence of NADPH until palmitate is formed. Inhibition of FAS causes an accumulation of intracellular malonyl-CoA, as this metabolite is essentially committed to fatty acid synthesis once formed. Detection of intracellular metabolites for screening can be problematic due to a lack of appropriate tools, but here we describe a targeted liquid chromatography-mass spectroscopy (LCMS) method to directly measure endogenous levels of malonyl-CoA to drive a drug development structure-activity relationship (SAR) screening cascade. Our process involves preparation of samples at 96-well scale, normalization postpermeabilization via use of a whole-well imaging platform, and the LCMS detection methodology. The assay is amenable to multiplexing cellular endpoints, has a typical Z' of >0.6, and has high reproducibility of EC50 values. PMID:26586251

  11. Tetra- and Pentacyclic Triterpene Acids from the Ancient Anti-inflammatory Remedy Frankincense as Inhibitors of Microsomal Prostaglandin E2 Synthase-1

    PubMed Central

    2014-01-01

    The microsomal prostaglandin E2 synthase (mPGES)-1 is the terminal enzyme in the biosynthesis of prostaglandin (PG)E2 from cyclooxygenase (COX)-derived PGH2. We previously found that mPGES-1 is inhibited by boswellic acids (IC50 = 3–30 μM), which are bioactive triterpene acids present in the anti-inflammatory remedy frankincense. Here we show that besides boswellic acids, additional known triterpene acids (i.e., tircuallic, lupeolic, and roburic acids) isolated from frankincense suppress mPGES-1 with increased potencies. In particular, 3α-acetoxy-8,24-dienetirucallic acid (6) and 3α-acetoxy-7,24-dienetirucallic acid (10) inhibited mPGES-1 activity in a cell-free assay with IC50 = 0.4 μM, each. Structure–activity relationship studies and docking simulations revealed concrete structure-related interactions with mPGES-1 and its cosubstrate glutathione. COX-1 and -2 were hardly affected by the triterpene acids (IC50 > 10 μM). Given the crucial role of mPGES-1 in inflammation and the abundance of highly active triterpene acids in frankincence extracts, our findings provide further evidence of the anti-inflammatory potential of frankincense preparations and reveal novel, potent bioactivities of tirucallic acids, roburic acids, and lupeolic acids. PMID:24844534

  12. Aldosterone Contributes to Elevated Left Ventricular Mass in Black Boys

    PubMed Central

    Murro, Diana G; Beavers, Melinda; Harshfield, Gregory A; Kapuku, Gaston K

    2012-01-01

    Background Left Ventricular Hypertrophy (LVH) poses a great risk of cardiovascular morbidity and mortality in adults and may pose a serious risk in children. Adult studies have shown Renin Angiotensin Aldosterone System (RAAS) levels are directly correlated with left ventricular mass index (LVMI). This purpose of this study is to explore race and sex-related effects of the RAAS on LVMI in adolescents. Methods Data was collected from a sample of 89 blacks (44 girls, 45 boys) and 102 whites (40 girls, 62 boys) ages 15–19. Data collected included, sex, age, body mass index (BMI), LVMI, baseline blood pressure, and levels of aldosterone and angiotensin II. Results In black males, increased aldosterone levels were correlated with decreased sodium excretion (r=−0.336, p=0.024), increased blood pressure (r=0.358, p=0.016), and increased LVMI (r=0.342, p=0.022). In black females, increased aldosterone levels correlated with increased baseline blood pressure (r=0.356, p=0.018). In white males, increased aldosterone was correlated decreased sodium excretion (r=−0.391, p=0.002). In white females, aldosterone levels correlated with increased baseline blood pressure (r=0.323, p=0.042) and decreased sodium excretion (r=−0.342, p=0.031). Conclusions The results suggest the following model in black males: increased aldosterone leads to increased sodium retention, causing a volume-mediated increase in blood pressure; increased blood pressure results in increased left ventricular mass and eventually LVH. PMID:23179199

  13. Molecular and Cellular Mechanisms of Aldosterone Producing Adenoma Development

    PubMed Central

    Boulkroun, Sheerazed; Fernandes-Rosa, Fabio Luiz; Zennaro, Maria-Christina

    2015-01-01

    Primary aldosteronism (PA) is the most common form of secondary hypertension with an estimated prevalence of ~10% in referred patients. PA occurs as a result of a dysregulation of the normal mechanisms controlling adrenal aldosterone production. It is characterized by hypertension with low plasma renin and elevated aldosterone and often associated with hypokalemia. The two major causes of PA are unilateral aldosterone producing adenoma (APA) and bilateral adrenal hyperplasia, accounting together for ~95% of cases. In addition to the well-characterized effect of excess mineralocorticoids on blood pressure, high levels of aldosterone also have cardiovascular, renal, and metabolic consequences. Hence, long-term consequences of PA include increased risk of coronary artery disease, myocardial infarction, heart failure, and atrial fibrillation. Despite recent progress in the management of patients with PA, critical issues related to diagnosis, subtype differentiation, and treatment of non-surgically correctable forms still persist. A better understanding of the pathogenic mechanisms of the disease should lead to the identification of more reliable diagnostic and prognostic biomarkers for a more sensitive and specific screening and new therapeutic options. In this review, we will summarize our current knowledge on the molecular and cellular mechanisms of APA development. On one hand, we will discuss how various animal models have improved our understanding of the pathophysiology of excess aldosterone production. On the other hand, we will summarize the major advances made during the last few years in the genetics of APA due to transcriptomic studies and whole exome sequencing. The identification of recurrent and somatic mutations in genes coding for ion channels (KCNJ5 and CACNA1D) and ATPases (ATP1A1 and ATP2B3) allowed highlighting the central role of calcium signaling in autonomous aldosterone production by the adrenal. PMID:26124749

  14. GM3 synthase gene is a novel biomarker for histological classification and drug sensitivity against epidermal growth factor receptor tyrosine kinase inhibitors in non-small cell lung cancer.

    PubMed

    Noguchi, Mariko; Suzuki, Tomoko; Kabayama, Kazuya; Takahashi, Hiroki; Chiba, Hirofumi; Shiratori, Masanori; Abe, Shosaku; Watanabe, Atsushi; Satoh, Masaaki; Hasegawa, Tadashi; Tagami, Seiichi; Ishii, Atsushi; Saitoh, Masaki; Kaneko, Masanori; Iseki, Ken; Igarashi, Yasuyuki; Inokuchi, Jin-ichi

    2007-10-01

    Expression of gangliosides and alterations in their composition have been observed during cell proliferation and differentiation and in certain cell cycle phases, brain development and cancer malignancy. To investigate the characteristics of GM3 synthase, SAT-I mRNA and ganglioside GM3 expression levels in lung cancer, we examined the expression levels of SAT-I mRNA as well as GM3 in 40 tumor tissues surgically removed from non-small cell lung cancer patients. Adenocarcinoma tissues expressed SAT-I mRNA levels that were significantly higher than those of squamous and other carcinomas (P < 0.0001). Moreover, the SAT-I mRNA levels were high in the bronchioalveolar carcinoma subtype and low in the solid and mucin subtypes of adenocarcinomas (P = 0.049, 0.049 and 0.013, respectively). To clarify the relationship between SAT-I mRNA and epidermal growth factor receptor (EGFR)-tyrosine kinase (TK) inhibitor sensitivity, we carried out drug sensitivity tests for the EGFR-TK inhibitors gefitinib and AG1478 using eight adenocarcinoma cell lines expressing no EGFR mutations. The IC(50) values for gefitinib and AG1478 decreased dramatically with increasing SAT-I mRNA levels (R(2) = 0.81 and 0.59, respectively), representing a wide range of drug sensitivities among adenocarcinoma cell lines. To explore a possible mechanism of how GM3 could enhance the sensitivity to EGFR-TK inhibitors, the SAT-I gene was introduced stably into a GM3-negative clone of murine 3LL lung cancer cells to produce GM3-reconstituted clones. We found an increase in EGFR protein levels and gefitinib sensitivity in GM3-reconstituted cells, suggesting the involvement of GM3 in the turnover of EGFR protein. Therefore, it is highly expected that, by measuring the expression levels of SAT-I mRNA in lung biopsy samples from non-small cell lung cancer patients, enhanced pathological identification and individualized chemotherapeutic strategies can be established for the appropriate use of EGFR-TK inhibitors

  15. Effect of the ATPase inhibitor protein IF{sub 1} on H{sup +} translocation in the mitochondrial ATP synthase complex

    SciTech Connect

    Zanotti, Franco; Gnoni, Antonio; Mangiullo, Roberto; Papa, Sergio

    2009-06-19

    The H{sup +} F{sub o}F{sub 1}-ATP synthase complex of coupling membranes converts the proton-motive force into rotatory mechanical energy to drive ATP synthesis. The F{sub 1} moiety of the complex protrudes at the inner side of the membrane, the F{sub o} sector spans the membrane reaching the outer side. The IF{sub 1} component of the mitochondrial complex is a basic 10 kDa protein, which inhibits the F{sub o}F{sub 1}-ATP hydrolase activity. The mitochondrial matrix pH is the critical factor for the inhibitory binding of the central segment of IF{sub 1} (residue 42-58) to the F{sub 1}-{alpha}/{beta} subunits. We have analyzed the effect of native purified IF{sub 1} the IF{sub 1}-(42-58) synthetic peptide and its mutants on proton conduction, driven by ATP hydrolysis or by [K{sup +}] gradients, in bovine heart inside-out submitochondrial particles and in liposome-reconstituted F{sub o}F{sub 1} complex. The results show that IF{sub 1}, and in particular its central 42-58 segment, displays different inhibitory affinity for proton conduction from the F{sub 1} to the F{sub o} side and in the opposite direction. Cross-linking of IF{sub 1} to F{sub 1}-{alpha}/{beta} subunits inhibits the ATP-driven H{sup +} translocation but enhances H{sup +} conduction in the reverse direction. These observation are discussed in terms of the rotary mechanism of the F{sub o}F{sub 1} complex.

  16. New Inducible Nitric Oxide Synthase and Cyclooxygenase-2 Inhibitors, Nalidixic Acid Linked to Isatin Schiff Bases via Certain l-Amino Acid Bridges.

    PubMed

    Naglah, Ahmed M; Ahmed, Atallah F; Wen, Zhi-Hong; Al-Omar, Mohamed A; Amr, Abd El-Galil E; Kalmouch, Atef

    2016-01-01

    A series of new Schiff bases were synthesized by condensation of isatins with the nalidixic acid-l-amino acid hydrazides. Prior to hydrazide formation, a peptide linkage has been prepared via coupling of nalidixic acid with appropriate l-amino acid methyl esters to yield 3a-c. The chemical structures of the new Schiff bases (5b and 5d-h) were confirmed by means of IR, NMR, mass spectroscopic, and elemental analyses. The anti-inflammatory activity of these Schiff bases was evaluated via measurement of the expressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells model. The Schiff bases exhibited significant dual inhibitory effect against the induction of the pro-inflammatory iNOS and COX-2 proteins with variable potencies. However, they strongly down-regulated the iNOS expression to the level of 16.5% ± 7.4%-42.2% ± 19.6% compared to the effect on COX-2 expression (<56.4% ± 3.1% inhibition) at the same concentration (10 μM). The higher iNOS inhibition activity of the tested Schiff bases, relative to that of COX-2, seems to be a reflection of the combined suppressive effects exerted by their nalidixic acid, isatins (4a-c), and l-amino acid moieties against iNOS expression. These synthesized nalidixic acid-l-amino acid-isatin conjugates can be regarded as a novel class of anti-inflammatory antibacterial agents. PMID:27092477

  17. Distribution of Callose Synthase, Cellulose Synthase, and Sucrose Synthase in Tobacco Pollen Tube Is Controlled in Dissimilar Ways by Actin Filaments and Microtubules1[W

    PubMed Central

    Cai, Giampiero; Faleri, Claudia; Del Casino, Cecilia; Emons, Anne Mie C.; Cresti, Mauro

    2011-01-01

    Callose and cellulose are fundamental components of the cell wall of pollen tubes and are probably synthesized by distinct enzymes, callose synthase and cellulose synthase, respectively. We examined the distribution of callose synthase and cellulose synthase in tobacco (Nicotiana tabacum) pollen tubes in relation to the dynamics of actin filaments, microtubules, and the endomembrane system using specific antibodies to highly conserved peptide sequences. The role of the cytoskeleton and membrane flow was investigated using specific inhibitors (latrunculin B, 2,3-butanedione monoxime, taxol, oryzalin, and brefeldin A). Both enzymes are associated with the plasma membrane, but cellulose synthase is present along the entire length of pollen tubes (with a higher concentration at the apex) while callose synthase is located in the apex and in distal regions. In longer pollen tubes, callose synthase accumulates consistently around callose plugs, indicating its involvement in plug synthesis. Actin filaments and endomembrane dynamics are critical for the distribution of callose synthase and cellulose synthase, showing that enzymes are transported through Golgi bodies and/or vesicles moving along actin filaments. Conversely, microtubules appear to be critical in the positioning of callose synthase in distal regions and around callose plugs. In contrast, cellulose synthases are only partially coaligned with cortical microtubules and unrelated to callose plugs. Callose synthase also comigrates with tubulin by Blue Native-polyacrylamide gel electrophoresis. Membrane sucrose synthase, which expectedly provides UDP-glucose to callose synthase and cellulose synthase, binds to actin filaments depending on sucrose concentration; its distribution is dependent on the actin cytoskeleton and the endomembrane system but not on microtubules. PMID:21205616

  18. The Role of Aldosterone in Obesity-Related Hypertension.

    PubMed

    Kawarazaki, Wakako; Fujita, Toshiro

    2016-04-01

    Obese subjects often have hypertension and related cardiovascular and renal diseases, and this has become a serious worldwide health problem. In obese subjects, impaired renal-pressure natriuresis causes sodium retention, leading to the development of salt-sensitive hypertension. Physical compression of the kidneys by visceral fat and activation of the sympathetic nervous system, renin-angiotensin systems (RAS), and aldosterone/mineralocorticoid receptor (MR) system are involved in this mechanism. Obese subjects often exhibit hyperaldosteronism, with increased salt sensitivity of blood pressure (BP). Adipose tissue excretes aldosterone-releasing factors, thereby stimulating aldosterone secretion independently of the systemic RAS, and aldosterone/MR activation plays a key role in the development of hypertension and organ damage in obesity. In obese subjects, both salt sensitivity of BP, enhanced by obesity-related metabolic disorders including aldosterone excess, and increased dietary sodium intake are closely related to the incidence of hypertension. Some salt sensitivity-related gene variants affect the risk of obesity, and together with salt intake, its combination is possibly associated with the development of hypertension in obese subjects. With high salt levels common in modern diets, salt restriction and weight control are undoubtedly important. However, not only MR blockade but also new diagnostic modalities and therapies targeting and modifying genes that are related to salt sensitivity, obesity, or RAS regulation are expected to prevent obesity and obesity-related hypertension. PMID:26927805

  19. Bilateral Adrenocortical Masses Producing Aldosterone and Cortisol Independently

    PubMed Central

    Lee, Seung-Eun; Lee, You-Bin; Seok, Hyeri; Shin, In Seub; Eun, Yeong Hee; Kim, Jung-Han; Oh, Young Lyun

    2015-01-01

    A 31-year-old woman was referred to our hospital with symptoms of hypertension and bilateral adrenocortical masses with no feature of Cushing syndrome. The serum aldosterone/renin ratio was elevated and the saline loading test showed no suppression of the plasma aldosterone level, consistent with a diagnosis of primary hyperaldosteronism. Overnight and low-dose dexamethasone suppression tests showed no suppression of serum cortisol, indicating a secondary diagnosis of subclinical Cushing syndrome. Adrenal vein sampling during the low-dose dexamethasone suppression test demonstrated excess secretion of cortisol from the left adrenal mass. A partial right adrenalectomy was performed, resulting in normalization of blood pressure, hypokalemia, and high aldosterone level, implying that the right adrenal mass was the main cause of the hyperaldosteronism. A total adrenalectomy for the left adrenal mass was later performed, resulting in a normalization of cortisol level. The final diagnosis was bilateral adrenocortical adenomas, which were secreting aldosterone and cortisol independently. This case is the first report of a concurrent cortisol-producing left adrenal adenoma and an aldosterone-producing right adrenal adenoma in Korea, as demonstrated by adrenal vein sampling and sequential removal of adrenal masses. PMID:26248855

  20. Bilateral Adrenocortical Masses Producing Aldosterone and Cortisol Independently.

    PubMed

    Lee, Seung Eun; Kim, Jae Hyeon; Lee, You Bin; Seok, Hyeri; Shin, In Seub; Eun, Yeong Hee; Kim, Jung Han; Oh, Young Lyun

    2015-12-01

    A 31-year-old woman was referred to our hospital with symptoms of hypertension and bilateral adrenocortical masses with no feature of Cushing syndrome. The serum aldosterone/renin ratio was elevated and the saline loading test showed no suppression of the plasma aldosterone level, consistent with a diagnosis of primary hyperaldosteronism. Overnight and low-dose dexamethasone suppression tests showed no suppression of serum cortisol, indicating a secondary diagnosis of subclinical Cushing syndrome. Adrenal vein sampling during the low-dose dexamethasone suppression test demonstrated excess secretion of cortisol from the left adrenal mass. A partial right adrenalectomy was performed, resulting in normalization of blood pressure, hypokalemia, and high aldosterone level, implying that the right adrenal mass was the main cause of the hyperaldosteronism. A total adrenalectomy for the left adrenal mass was later performed, resulting in a normalization of cortisol level. The final diagnosis was bilateral adrenocortical adenomas, which were secreting aldosterone and cortisol independently. This case is the first report of a concurrent cortisol-producing left adrenal adenoma and an aldosterone-producing right adrenal adenoma in Korea, as demonstrated by adrenal vein sampling and sequential removal of adrenal masses. PMID:26248855

  1. Renin-angiotensin-aldosterone system blockade in chronic kidney disease: current strategies and a look ahead.

    PubMed

    Viazzi, Francesca; Bonino, Barbara; Cappadona, Francesca; Pontremoli, Roberto

    2016-08-01

    The Renin-Angiotensin-Aldosterone System (RAAS) is profoundly involved in the pathogenesis of renal and cardiovascular organ damage, and has been the preferred therapeutic target for renal protection for over 30 years. Monotherapy with either an Angiotensin Converting Enzime Inhibitor (ACE-I) or an Angiotensin Receptor Blocker (ARB), together with optimal blood pressure control, remains the mainstay treatment for retarding the progression toward end-stage renal disease. Combining ACE-Is and ARBs, or either one with an Aldosterone Receptor Antagonist (ARA), has been shown to provide greater albuminuria reduction, and to possibly improve renal outcome, but at an increased risk of potentially severe side effects. Moreover, combination therapy has failed to provide additional cardiovascular protection, and large prospective trials on hard renal endpoints are lacking. Therefore this treatment should, at present, be limited to selected patients with residual proteinuria and high renal risk. Future studies with novel agents, which directly act on the RAAS at multiple levels or have a more favourable side effect profile, are greatly needed to further explore and define the potential for and the limitations of profound pharmacologic RAAS inhibition. PMID:26984204

  2. Design, synthesis, biological evaluation and X-ray crystal structure of novel classical 6,5,6-tricyclic benzo[4,5]thieno[2,3-d]pyrimidines as dual thymidylate synthase and dihydrofolate reductase inhibitors

    PubMed Central

    Zhang, Xin; Zhou, Xilin; L.Kisliuk, Roy; Piraino, Jennifer; Cody, Vivian

    2011-01-01

    Classical antifolates (4-7) with a tricyclic benzo[4,5]thieno[2,3-d]pyrimidine scaffold and a flexible and rigid benzoylglutamate were synthesized as dual thymidylate synthase (TS) and dihydrofolate reductase (DHFR) inhibitors. Oxidative aromatization of ethyl 2-amino-4-methyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carboxylate (±)-9 to ethyl 2-amino-4-methyl-1-benzothiophene-3-carboxylate 10 with 10% Pd/C was a key synthetic step. Compounds with 2-CH3 substituents inhibited human (h) TS (IC50 = 0.26-0.8 μM), but not hDHFR. Substitution of the 2-CH3 with a 2-NH2 increases hTS inhibition by more than 10-fold and also affords excellent hDHFR inhibition (IC50 = 0.09-0.1 μM). This study shows that the tricyclic benzo[4,5]thieno[2,3-d]pyrimidine scaffold is highly conducive to single hTS or dual hTS-hDHFR inhibition depending on the 2-position substituents. The X-ray crystal structures of 6 and 7 with hDHFR reveal, for the first time, that tricyclics 6 and 7 bind with the benzo[4,5]thieno[2,3-d]pyrimidine ring in the folate binding mode with the thieno S mimicking the 4-amino of methotrexate. PMID:21550809

  3. Chronobiology and Pharmacologic Modulation of the Renin-Angiotensin-Aldosterone System in Dogs: What Have We Learned?

    PubMed

    Mochel, Jonathan P; Danhof, Meindert

    2015-01-01

    Congestive heart failure (CHF) is a primary cause of morbidity and mortality with an increasing prevalence in human and canine populations. Recognition of the role of renin-angiotensin-aldosterone system (RAAS) overactivation in the pathophysiology of CHF has led to significant medical advances. By decreasing systemic vascular resistance and angiotensin II (AII) production, angiotensin-converting enzyme (ACE) inhibitors such as benazepril improve cardiac hemodynamics and reduce mortality in human and dog CHF patients. Although several experiments have pointed out that efficacy of ACE inhibitors depends on the time of administration, little attention is paid to the optimum time of dosing of these medications. A thorough characterization of the chronobiology of the renin cascade has the potential to streamline the therapeutic management of RAAS-related diseases and to help determining the optimal time of drug administration that maximizes efficacy of ACE inhibitors, while minimizing the occurrence of adverse effects. We have developed an integrated pharmacokinetic-pharmacodynamic model that adequately captures the disposition kinetics of the paradigm drug benazeprilat, as well as the time-varying changes of systemic renin-angiotensin-aldosterone biomarkers, without and with ACE inhibition therapy. Based on these chronobiological investigations, the optimal efficacy of ACE inhibitors is expected with bedtime dosing. The data further show that benazepril influences the dynamics of the renin-angiotensin-aldosterone cascade, resulting in a profound decrease in AII and aldosterone (ALD), while increasing renin activity for about 24 h. From the results of recent investigations in human, it is hypothesized that reduction of AII and ALD is one of the drivers of increased survival and improved quality of life in dogs receiving ACE inhibitors. To support and consolidate this hypothesis, additional efforts should be directed toward the collection of circulating RAAS peptides

  4. 4-Hydroxy-3-(naphthalen-1-ylmethyl)thiophen-2(5H)-one as inhibitors of tyrosyl-tRNA synthase: Synthesis, molecular docking and antibacterial evaluation

    NASA Astrophysics Data System (ADS)

    Sun, Juan; Liu, Jia-Jia; Zhou, Wei; Guo, Feng-Jiao; Wang, Xin-Yi; Zhu, Hai-Liang

    2014-01-01

    A series of novel 4-hydroxy-3-(naphthalen-1-ylmethyl)thiophen-2(5H)-ones as tyrosyl-tRNA synthetase inhibitors were synthesized. Of these compounds, 4-(naphthalen-1-ylmethyl)-5-oxo-2,5-dihydrothiophen-3-yl-2-(4-hydroxyphenyl)acetate (29) was the most potent. The binding model and structure-activity relationship indicate that replacement of phenyl acetate in the side chain of 29 with a substituent containing more hydrophilic groups would be more suitable for further modification. Antibacterial assay revealed that the synthetic compounds are effective against growth of Gram-positive organisms, and 29 is the most potent agent against Staphylococcus aureus ATCC 25923 with MIC50 value of 0.21 μg/mL.

  5. A Comparison of the Effects of Neuronal Nitric Oxide Synthase and Inducible Nitric Oxide Synthase Inhibition on Cartilage Damage

    PubMed Central

    Gokay, Nevzat Selim; Yilmaz, Ibrahim; Demiroz, Ahu Senem; Gokce, Alper; Dervisoglu, Sergülen; Gokay, Banu Vural

    2016-01-01

    The objective of this study was to investigate the effects of selective inducible nitric oxide synthase and neuronal nitric oxide synthase inhibitors on cartilage regeneration. The study involved 27 Wistar rats that were divided into five groups. On Day 1, both knees of 3 rats were resected and placed in a formalin solution as a control group. The remaining 24 rats were separated into 4 groups, and their right knees were surgically damaged. Depending on the groups, the rats were injected with intra-articular normal saline solution, neuronal nitric oxide synthase inhibitor 7-nitroindazole (50 mg/kg), inducible nitric oxide synthase inhibitor amino-guanidine (30 mg/kg), or nitric oxide precursor L-arginine (200 mg/kg). After 21 days, the right and left knees of the rats were resected and placed in formalin solution. The samples were histopathologically examined by a blinded evaluator and scored on 8 parameters. Although selective neuronal nitric oxide synthase inhibition exhibited significant (P = 0.044) positive effects on cartilage regeneration following cartilage damage, it was determined that inducible nitric oxide synthase inhibition had no statistically significant effect on cartilage regeneration. It was observed that the nitric oxide synthase activation triggered advanced arthrosis symptoms, such as osteophyte formation. The fact that selective neuronal nitric oxide synthase inhibitors were observed to have mitigating effects on the severity of the damage may, in the future, influence the development of new agents to be used in the treatment of cartilage disorders. PMID:27382570

  6. Renin-Angiotensin-Aldosterone Genotype Influences Ventricular Remodeling in Infants with Single Ventricle

    PubMed Central

    Mital, Seema; Chung, Wendy K.; Colan, Steven D.; Sleeper, Lynn A.; Manlhiot, Cedric; Arrington, Cammon B.; Cnota, James F.; Graham, Eric M.; Mitchell, Michael E.; Goldmuntz, Elizabeth; Li, Jennifer S.; Levine, Jami C.; Lee, Teresa M.; Margossian, Renee; Hsu, Daphne T.

    2011-01-01

    Background We investigated the effect of polymorphisms in the renin-angiotensin-aldosterone system (RAAS) genes on ventricular remodeling, growth, renal function and response to enalapril in infants with single ventricle. Methods and Results Single ventricle infants enrolled in a randomized trial of enalapril were genotyped for polymorphisms in 5 genes: angiotensinogen, angiotensin-converting enzyme, angiotensin II type 1 receptor, aldosterone synthase, and chymase. Alleles associated with RAAS upregulation were classified as risk alleles. Ventricular mass, volume, somatic growth, renal function using estimated glomerular filtration rate (eGFR), and response to enalapril were compared between patients with ≥2 homozygous risk genotypes (high-risk), and those with <2 homozygous risk genotypes (low-risk) at two time points - before the superior-cavopulmonary-connection (pre-SCPC) and at age 14 months. Of 230 trial subjects, 154 were genotyped: 38 were high-risk, 116 were low-risk. Ventricular mass and volume were elevated in both groups pre-SCPC. Ventricular mass and volume decreased and eGFR increased after SCPC in the low-risk (p<0.05) but not the high-risk group. These responses were independent of enalapril treatment. Weight and height z-scores were lower at baseline and height remained lower in the high-risk group at 14 months especially in those receiving enalapril (p<0.05). Conclusions RAAS-upregulation genotypes were associated with failure of reverse remodeling after SCPC surgery, less improvement in renal function, and impaired somatic growth, the latter especially in patients receiving enalapril. RAAS genotype may identify a high-risk subgroup of single ventricle patients who fail to fully benefit from volume unloading surgery. Follow-up is warranted to assess longterm impact. Clinical Trial Registration Clinical Trials.gov Identifier NCT00113087 PMID:21576655

  7. Aldosterone, Renin, and Diabetes Mellitus in African Americans: The Jackson Heart Study.

    PubMed

    Joseph, Joshua J; Echouffo-Tcheugui, Justin B; Kalyani, Rita R; Yeh, Hsin-Chieh; Bertoni, Alain G; Effoe, Valery S; Casanova, Ramon; Sims, Mario; Correa, Adolfo; Wu, Wen-Chih; Wand, Gary S; Golden, Sherita H

    2016-04-01

    We examined the association of both aldosterone and renin, with insulin resistance, β-cell function, and incident diabetes in a large African American cohort. Renin-angiotensin-aldosterone system with higher levels of aldosterone and renin is associated with insulin resistance, compensatory increased β-cell function and incident diabetes in African Americans. PMID:26908112

  8. A Case of Glucocorticoid Remediable Aldosteronism and Thoracoabdominal Aneurysms

    PubMed Central

    Shahrrava, Anahita; Moinuddin, Sunnan; Boddu, Prajwal; Shah, Rohan

    2016-01-01

    Glucocorticoid remediable aldosteronism (GRA) is rare familial form of primary aldosteronism characterized by a normalization of hypertension with the administration of glucocorticoids. We present a case of GRA and thoracoabdominal aneurysm complicated by multiple aortic dissections requiring complex surgical and endovascular repairs. Registry studies have shown a high rate of intracranial aneurysms in GRA patients with high case fatality rates. The association of thoracoabdominal aneurysms with GRA has not been described, thus far, in literature. Studies have shown that high tissue aldosterone levels concomitant with salt intake have a significant role in the pathogenesis of aneurysms and this may explain the formation of aneurysms in the intracranial vasculature and aorta. The association of GRA with thoracic aortic aneurysms needs to be further studied to develop screening recommendations for early identification and optimal treatment. Also, the early use of mineralocorticoid antagonists may have a significant preventive and attenuating effect in aneurysm formation, an association which needs to be confirmed in future studies. PMID:27366333

  9. Effect of swimming on the production of aldosterone in rats.

    PubMed

    Lieu, Fu-Kong; Lin, Chih-Yung; Wang, Paulus S; Jian, Cai-Yun; Yeh, Yung-Hsing; Chen, Yi-An; Wang, Kai-Lee; Lin, Yi-Chun; Chang, Ling-Ling; Wang, Guei-Jane; Wang, Shyi-Wu

    2014-01-01

    It has been demonstrated that exercise is one of the stresses known to increase the aldosterone secretion. Both potassium and angiotensin II (Ang II) levels are shown to be correlated with aldosterone production during exercise, but the mechanism is still unclear. In an in vivo study, male rats were catheterized via right jugular vein (RJV), and divided into four groups namely water immersion, swimming, lactate infusion (13 mg/kg/min) and pyruvate infusion (13 mg/kg/min) groups. Each group was treated for 10 min. Blood samples were collected at 0, 10, 15, 30, 60 and 120 min from RJV after administration. In an in vitro study, rat zona glomerulosa (ZG) cells were challenged by lactate (1-10 mM) in the presence or absence of Ang II (10(-8) M) for 60 min. The levels of aldosterone in plasma and medium were measured by radioimmunoassay. Cell lysates were analyzed by immunoblotting assay. After exercise and lactate infusion, plasma levels of aldosterone and lactate were significantly higher than those in the control group. Swimming for 10 min significantly increased the plasma Ang II levels in male rats. Administration of lactate plus Ang II significantly increased aldosterone production and enhanced protein expression of steroidogenic acute regulatory protein (StAR) in ZG cells. These results demonstrated that acute exercise led to the increase of both aldosterone and Ang II secretion, which is associated with lactate action on ZG cells and might be dependent on the activity of renin-angiotensin system. PMID:25289701

  10. Effect of Swimming on the Production of Aldosterone in Rats

    PubMed Central

    Wang, Paulus S.; Jian, Cai-Yun; Yeh, Yung-Hsing; Chen, Yi-An; Wang, Kai-Lee; Lin, Yi-Chun; Chang, Ling-Ling; Wang, Guei-Jane; Wang, Shyi-Wu

    2014-01-01

    It has been demonstrated that exercise is one of the stresses known to increase the aldosterone secretion. Both potassium and angiotensin II (Ang II) levels are shown to be correlated with aldosterone production during exercise, but the mechanism is still unclear. In an in vivo study, male rats were catheterized via right jugular vein (RJV), and divided into four groups namely water immersion, swimming, lactate infusion (13 mg/kg/min) and pyruvate infusion (13 mg/kg/min) groups. Each group was treated for 10 min. Blood samples were collected at 0, 10, 15, 30, 60 and 120 min from RJV after administration. In an in vitro study, rat zona glomerulosa (ZG) cells were challenged by lactate (1–10 mM) in the presence or absence of Ang II (10−8 M) for 60 min. The levels of aldosterone in plasma and medium were measured by radioimmunoassay. Cell lysates were analyzed by immunoblotting assay. After exercise and lactate infusion, plasma levels of aldosterone and lactate were significantly higher than those in the control group. Swimming for 10 min significantly increased the plasma Ang II levels in male rats. Administration of lactate plus Ang II significantly increased aldosterone production and enhanced protein expression of steroidogenic acute regulatory protein (StAR) in ZG cells. These results demonstrated that acute exercise led to the increase of both aldosterone and Ang II secretion, which is associated with lactate action on ZG cells and might be dependent on the activity of renin-angiotensin system. PMID:25289701

  11. The Metabolism and Secretion of Aldosterone in Elderly Subjects*

    PubMed Central

    Flood, C.; Gherondache, C.; Pincus, G.; Tait, J. F.; Tait, S. A. S.; Willoughby, S.

    1967-01-01

    The secretion rates [34 ± 6 (SE) μg per day, 9 subjects] and metabolic clearance rates (MCR) [1,288 ± 120 (SE) L of plasma per day, 9 subjects] of aldosterone in elderly subjects are significantly lower than those of young subjects [77 ± 7 (SE) μg per day and 1,631 ± 106 (SE) L per day, respectively]. There is a correlation of the MCR and secretion rate values (p = 0.02), but the calculated plasma concentrations (secretion rate/MCR) are also significantly low in the elderly subjects [2.6 ± 0.3 (SE) compared with concentrations in the plasma from young subjects of 4.7 ± 0.6 (SE) μg per 100 ml plasma]. The urinary excretion of radioactivity from oral and intravenously administered labeled aldosterone as aldosterone in the neutral extract, as aldosterone released by acid hydrolysis, and as tetrahydroaldosterone released by incubation with β-glucuronidase is generally similar for young and elderly subjects except that a larger portion of the oral compared with the intravenous dose is excreted as free aldosterone in the elderly subjects, indicating that the splanchnic extraction is reduced. The calculated splanchnic blood flow (assuming no alteration in extrasplanchnic metabolism) is also slightly lowered. Therefore, as in patients with mild cardiac dysfunction, the lowered MCR of subjects is due to both reduced splanchnic extraction and blood flow. However, unlike the heart failure patients, in the elderly subjects the plasma concentration of aldosterone is also reduced. PMID:6026101

  12. [The effect of aldosterone A on renal potassium excretion].

    PubMed

    Winther, Signe Abitz; Egfjord, Martin

    2011-01-10

    Recent studies have shown expression of the following regulatory WNK kinases in the kidney: the full-length WNK1 (L-WNK1), the shorter kidney specific WNK1 transcript (KS-WNK1), formed by alternative splicing, and WNK4. Aldosterone activates expression of KS-WNK1 and inhibits WNK4 via SGK1 - both leading to stimulation of ENaC and activation of ROMK, and increased potassium excretion. Thus, further characterization of the WNK system may lead to elucidation of the dual anti-natriuretic and kaliuretic effects of aldosterone, in situations where only activation of one of these effects is needed. PMID:21219845

  13. Severe hypertension in primary aldosteronism and good response to surgery.

    PubMed

    Clarke, D; Wilkinson, R; Johnston, I D; Hacking, P M; Haggith, J W

    1979-03-01

    11 patients with primary aldosteronism have been encountered over 11 years and submitted to surgery in a provincial teaching hospital serving a population of 3 million. Contrary to classical teaching, the hypertension has usually been very severe. Precise identification of the site of the lesion preoperatively has been possible by the measurement of adrenal-vein aldosterone levels, and results of surgery have been excellent. The iodocholesterol adrenal scan also correctly identified the site of the adenoma in 5 out of 7 patients in which it was used. Adrenal venography was of little value except in siting catheters. PMID:85065

  14. New Monocyclic, Bicyclic, and Tricyclic Ethynylcyanodienones as Activators of the Keap1/Nrf2/ARE Pathway and Inhibitors of Inducible Nitric Oxide Synthase.

    PubMed

    Li, Wei; Zheng, Suqing; Higgins, Maureen; Morra, Rocco P; Mendis, Anne T; Chien, Chih-Wei; Ojima, Iwao; Mierke, Dale F; Dinkova-Kostova, Albena T; Honda, Tadashi

    2015-06-11

    A monocyclic compound 3 (3-ethynyl-3-methyl-6-oxocyclohexa-1,4-dienecarbonitrile) is a highly reactive Michael acceptor leading to reversible adducts with nucleophiles, which displays equal or greater potency than the pentacyclic triterpenoid CDDO in inflammation and carcinogenesis related assays. Recently, reversible covalent drugs, which bind with protein targets but not permanently, have been gaining attention because of their unique features. To explore such reversible covalent drugs, we have synthesized monocyclic, bicyclic, and tricyclic compounds containing 3 as an electrophilic fragment and evaluated them as activators of the Keap1/Nrf2/ARE pathway and inhibitors of iNOS. Notably, these compounds maintain the unique features of the chemical reactivity and biological potency of 3. Among them, a monocyclic compound 5 is the most potent in these assays while a tricyclic compound 14 displays a more robust and specific activation profile compared to 5. In conclusion, we demonstrate that 3 is a useful electrophilic fragment for exploring reversible covalent drugs. PMID:25965897

  15. [Heme oxygenase activity in the tissues of the vessels and heart of rats under co-administration of NO-synthase inhibitor and hemin chloride].

    PubMed

    Kaliman, P A; Filimonenko, V P; Nikitchenko, I V

    2008-01-01

    The administration of hemin chloride in a dose of 1.5 mg/100 g of the body weight was found to cause accumulation of the total heme and TBA-reactive products in the rat blood serum and vessels. Pretreatment by N(omega)-nitro-L-arginine (0.5 h before hemin chloride administration) did not affect the dynamics of the total heme and TBA-reacting products accumulation. The increase of heme oxygenase activity was observed in the vessels after hemin chloride administration. This effect was strengthened by N(omega)-nitro-L-arginine pretreatment. The changes of heme oxygenase activity and the total heme level in heart were not observed at any periods studied. The increase of the TBA-reactive products level in the heart after exogenous hemin injection was accompanied by an increase of nitrites content and blocked by pretreatment of NOS inhibitor. The N(omega)-nitro-L-arginine alone caused the accumulation of the total heme, TBA-reacting products and the increase of heme oxygenase activity in the vessels. The role of heme and NO in regulation of the heme oxygenase activity is discussed. PMID:18819384

  16. Role of the anterior region of the third ventricle in the cardiovascular responses produced by systemic injection of a nitric oxide synthase inhibitor

    NASA Technical Reports Server (NTRS)

    Lewis, S. J.; Whalen, E. J.; Beltz, T. G.; Johnson, A. K.

    1999-01-01

    This study examined whether a prior electrolytic lesion of the tissue surrounding the anteroventral third ventricle (AV3V) would affect the increase in mean arterial blood pressure (MAP) and the fall in heart rate (HR) produced by systemic injection of the nitric oxide synthesis (NOS) inhibitor, NG-nitro-L-arginine methyl ester (L-NAME; 25 micromol/kg, i.v.) in conscious rats. L-NAME produced a smaller increase in MAP in AV3V-lesion than in sham-lesion rats (+19+/-3 vs. +40+/-3 mmHg, respectively; P<0.05). In contrast, L-NAME produced similar falls in HR in the AV3V-lesion and sham-lesion rats (-103+/-15 vs. -97+/-8 bpm, respectively; P<0.05). These findings demonstrate that the L-NAME-induced pressor response is dependent upon the integrity of the AV3V region, whereas the L-NAME-induced bradycardia is not. Copyright 1999 Elsevier Science B. V.

  17. Effect of aldosterone-producing adenoma on endothelial function and Rho-associated kinase activity in patients with primary aldosteronism.

    PubMed

    Matsumoto, Takeshi; Oki, Kenji; Kajikawa, Masato; Nakashima, Ayumu; Maruhashi, Tatsuya; Iwamoto, Yumiko; Iwamoto, Akimichi; Oda, Nozomu; Hidaka, Takayuki; Kihara, Yasuki; Kohno, Nobuoki; Chayama, Kazuaki; Goto, Chikara; Aibara, Yoshiki; Noma, Kensuke; Liao, James K; Higashi, Yukihito

    2015-04-01

    The purpose of this study was to evaluate vascular function and activity of Rho-associated kinases (ROCKs) in patients with primary aldosteronism. Vascular function, including flow-mediated vasodilation (FMD) and nitroglycerine-induced vasodilation, and ROCK activity in peripheral leukocytes were evaluated in 21 patients with aldosterone-producing adenoma (APA), 23 patients with idiopathic hyperaldosteronism (IHA), and 40 age-, sex-, and blood pressure-matched patients with essential hypertension (EHT). FMD was significantly lower in the APA group than in the IHA and EHT groups (3.2±2.0% versus 4.6±2.3% and 4.4±2.2%; P<0.05, respectively), whereas there was no significant difference in FMD between the IHA and EHT groups. There was no significant difference in nitroglycerine-induced vasodilation in the 3 groups. ROCK activity was higher in the APA group than in the IHA and EHT groups (1.29±0.57 versus 1.00±0.46 and 0.81±0.36l; P<0.05, respectively), whereas there was no significant difference in ROCK activity between the IHA and EHT groups. FMD correlated with age (r=-0.31; P<0.01), plasma aldosterone concentration (r=-0.35; P<0.01), and aldosterone:renin ratio (r=-0.34; P<0.01). ROCK activity correlated with age (r=-0.24; P=0.04), plasma aldosterone concentration (r=0.33; P<0.01), and aldosterone:renin ratio (r=0.46; P<0.01). After adrenalectomy, FMD and ROCK activity were restored in patients with APA. APA was associated with both endothelial dysfunction and increased ROCK activity compared with those in IHA and EHT. APA may have a higher risk of future cardiovascular events. PMID:25624340

  18. Effects of Renin-Angiotensin-Aldosterone System Blockade in Patients with End-Stage Renal Disease.

    PubMed

    Slomka, Teresa; Lennon, Emily S; Akbar, Hina; Gosmanova, Elvira O; Bhattacharya, Syamal K; Oliphant, Carrie S; Khouzam, Rami N

    2016-03-01

    Blockers of the renin-angiotensin-aldosterone system (RAAS), such as angiotensin-converting enzyme inhibitors and angiotensin receptor blockers are routinely used in patients with chronic kidney disease because of their cardiovascular (CV) and renoprotective effects. However, there are no uniform recommendations about RAAS blockers for CV protection in the end-stage renal disease (ESRD) population other than the preferred drug class for blood pressure control. This uncertainty stems from the fact that patients with ESRD were generally excluded from randomized controlled trials evaluating the cardioprotective benefits of RAAS blockers. It is important to weigh the potential harms associated with the use of RAAS blockers, such as electrolyte disturbances and worsening anemia, with their role in protection of residual kidney function, alleviation of thirst and potential CV benefits. The objective of this review is to summarize the current knowledge about the use of RAAS blockers in patients with ESRD. PMID:26992264

  19. Biomarkers of activation of renin-angiotensin-aldosterone system in heart failure: how useful, how feasible?

    PubMed

    Emdin, Michele; Fatini, Cinzia; Mirizzi, Gianluca; Poletti, Roberta; Borrelli, Chiara; Prontera, Concetta; Latini, Roberto; Passino, Claudio; Clerico, Aldo; Vergaro, Giuseppe

    2015-03-30

    Renin-angiotensin-aldosterone system (RAAS), participated by kidney, liver, vascular endothelium, and adrenal cortex, and counter-regulated by cardiac endocrine function, is a complex endocrine system regulating systemic functions, such as body salt and water homeostasis and vasomotion, in order to allow the accomplishment of physiological tasks, such as orthostasis, physical and emotional stimuli, and to react towards the hemorrhagic insult, in tight conjunction with other neurohormonal axes, namely the sympathetic nervous system, the endothelin and vasopressin systems. The systemic as well as the tissue RAAS are also dedicated to promote tissue remodeling, particularly relevant after damage, when chronic activation may configure as a maladaptive response, leading to fibrosis, hypertrophy and apoptosis, and organ dysfunction. RAAS activation is a fingerprint of systemic arterial hypertension, kidney dysfunction, vascular atherosclerotic disease, and is definitely an hallmark of heart failure, which rapidly shifts from organ disease to a disorder of neurohormonal regulatory systems. Chronic RAAS activation is an indirect or direct target of most effective pharmacological treatments in heart failure, such as beta-blockers, inhibitors of angiotensin converting enzyme, angiotensin receptor blockers, direct renin inhibitors, and mineralocorticoid receptor blockers. Biomarkers of RAAS activation are available, with different feasibility and accuracy, such as plasma renin activity, renin, angiotensin II, and aldosterone, which all accompany the increasing clinical severity of heart failure disease, and are well recognized prognostic factors, even in patients with optimal therapy. Polymorphisms influencing the expression and activity of RAAS pathways have been recognized as clinically relevant biomarkers, likely influencing either the individual clinical phenotype, or the response to drugs. This solid, growing evidence strongly suggests the rationale for the use of

  20. Role of the Renin-Angiotensin System and Aldosterone on Cardiometabolic Syndrome

    PubMed Central

    Stiefel, P.; Vallejo-Vaz, A. J.; García Morillo, S.; Villar, J.

    2011-01-01

    Aldosterone facilitates cardiovascular damage by increasing blood pressure and through different mechanisms that are independent of its effects on blood pressure. In this respect, recent evidence involves aldosterone in the pathogenesis of metabolic syndrome. Although this relationship is complex, there is some evidence suggesting that different factors may play an important role, such as insulin resistance, renin-angiotensin-aldosterone system, oxidative stress, sodium retention, increased sympathetic activity, levels of free fatty acids, or inflammatory cytokines and adipokines. In addition to the classical pathway by which aldosterone acts through the mineralocorticoid receptors leading to sodium retention, aldosterone also has other mechanisms that influence cardiovascular tissue remodelling. Finally, overweight and obesity promote the adrenal secretion of aldosterone, increasing the predisposition to type 2 diabetes mellitus. Further studies are needed to better establish therapeutic strategies that act on the blockade of mineralocorticoid receptor in the treatment and prevention of cardiovascular diseases related to the excess of aldosterone and the metabolic syndrome. PMID:21785705

  1. Activating mutations in CTNNB1 in aldosterone producing adenomas.

    PubMed

    Åkerström, Tobias; Maharjan, Rajani; Sven Willenberg, Holger; Cupisti, Kenko; Ip, Julian; Moser, Ana; Stålberg, Peter; Robinson, Bruce; Alexander Iwen, K; Dralle, Henning; Walz, Martin K; Lehnert, Hendrik; Sidhu, Stan; Gomez-Sanchez, Celso; Hellman, Per; Björklund, Peyman

    2016-01-01

    Primary aldosteronism (PA) is the most common cause of secondary hypertension with a prevalence of 5-10% in unreferred hypertensive patients. Aldosterone producing adenomas (APAs) constitute a large proportion of PA cases and represent a surgically correctable form of the disease. The WNT signaling pathway is activated in APAs. In other tumors, a frequent cause of aberrant WNT signaling is mutation in the CTNNB1 gene coding for β-catenin. Our objective was to screen for CTNNB1 mutations in a well-characterized cohort of 198 APAs. Somatic CTNNB1 mutations were detected in 5.1% of the tumors, occurring mutually exclusive from mutations in KCNJ5, ATP1A1, ATP2B3 and CACNA1D. All of the observed mutations altered serine/threonine residues in the GSK3β binding domain in exon 3. The mutations were associated with stabilized β-catenin and increased AXIN2 expression, suggesting activation of WNT signaling. By CYP11B2 mRNA expression, CYP11B2 protein expression, and direct measurement of aldosterone in tumor tissue, we confirmed the ability for aldosterone production. This report provides compelling evidence that aberrant WNT signaling caused by mutations in CTNNB1 occur in APAs. This also suggests that other mechanisms that constitutively activate the WNT pathway may be important in APA formation. PMID:26815163

  2. 21 CFR 862.1045 - Aldosterone test system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Aldosterone test system. 862.1045 Section 862.1045 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  3. 21 CFR 862.1045 - Aldosterone test system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Aldosterone test system. 862.1045 Section 862.1045 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  4. 21 CFR 862.1045 - Aldosterone test system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Aldosterone test system. 862.1045 Section 862.1045 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  5. 21 CFR 862.1045 - Aldosterone test system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Aldosterone test system. 862.1045 Section 862.1045 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  6. 21 CFR 862.1045 - Aldosterone test system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Aldosterone test system. 862.1045 Section 862.1045 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems §...

  7. Reversible heart rhythm complexity impairment in patients with primary aldosteronism

    NASA Astrophysics Data System (ADS)

    Lin, Yen-Hung; Wu, Vin-Cent; Lo, Men-Tzung; Wu, Xue-Ming; Hung, Chi-Sheng; Wu, Kwan-Dun; Lin, Chen; Ho, Yi-Lwun; Stowasser, Michael; Peng, Chung-Kang

    2015-08-01

    Excess aldosterone secretion in patients with primary aldosteronism (PA) impairs their cardiovascular system. Heart rhythm complexity analysis, derived from heart rate variability (HRV), is a powerful tool to quantify the complex regulatory dynamics of human physiology. We prospectively analyzed 20 patients with aldosterone producing adenoma (APA) that underwent adrenalectomy and 25 patients with essential hypertension (EH). The heart rate data were analyzed by conventional HRV and heart rhythm complexity analysis including detrended fluctuation analysis (DFA) and multiscale entropy (MSE). We found APA patients had significantly decreased DFAα2 on DFA analysis and decreased area 1-5, area 6-15, and area 6-20 on MSE analysis (all p < 0.05). Area 1-5, area 6-15, area 6-20 in the MSE study correlated significantly with log-transformed renin activity and log-transformed aldosterone-renin ratio (all p < = 0.01). The conventional HRV parameters were comparable between PA and EH patients. After adrenalectomy, all the altered DFA and MSE parameters improved significantly (all p < 0.05). The conventional HRV parameters did not change. Our result suggested that heart rhythm complexity is impaired in APA patients and this is at least partially reversed by adrenalectomy.

  8. Comparison of two radioimmunoassay kits for aldosterone determination.

    PubMed

    Sampson, E J; Derck, D D; Demers, L M

    1976-08-01

    Two commercially available radioimmunoassay kits for aldosterone determination not requiring preliminary chromatographic purification were examined. Aldosterone standard curve solutions prepared from the CIS kit, Nuclear International Corp., (x-axis) and Diagnostic Products kit (y-axis) were assayed with both kits and the results yielded a regression equation of y = 0.834x + 0.08 nmol/liter. Analytical recovery experiments with aldosterone added to urine and serum showed 120% and 101% recovery with the CIS kit, respectively, and 92% and 92% recovery with the Diagnostic Products kit, respectively. Both kits demonstrated good parallelism with urine and serum. Antibody specificity was tested with six structurally related steroids and each kit showed virtually no cross-reactivity at clinically normal serum concentrations. Serum aldosterone values were compared before (y-axis) and after (x-axis) column chromatography on Sephadex LH-20, with the following regression equations: y = 1.070x + 0.092 nmol/liter for the CIS kit and y = 1.023x + 0.093 nmol/liter for the Diagnostic Products kit. Regression equations comparing patient samples between kits, CIS (x-axis) and Diagnostic Products (y-axis), were: y = 0.832x + 0.007 mumol/24 h with urine and y = 0.850x + 0.097 nmol/liter with serum. PMID:954186

  9. Activating mutations in CTNNB1 in aldosterone producing adenomas

    PubMed Central

    Åkerström, Tobias; Maharjan, Rajani; Sven Willenberg, Holger; Cupisti, Kenko; Ip, Julian; Moser, Ana; Stålberg, Peter; Robinson, Bruce; Alexander Iwen, K.; Dralle, Henning; Walz, Martin K.; Lehnert, Hendrik; Sidhu, Stan; Gomez-Sanchez, Celso; Hellman, Per; Björklund, Peyman

    2016-01-01

    Primary aldosteronism (PA) is the most common cause of secondary hypertension with a prevalence of 5–10% in unreferred hypertensive patients. Aldosterone producing adenomas (APAs) constitute a large proportion of PA cases and represent a surgically correctable form of the disease. The WNT signaling pathway is activated in APAs. In other tumors, a frequent cause of aberrant WNT signaling is mutation in the CTNNB1 gene coding for β-catenin. Our objective was to screen for CTNNB1 mutations in a well-characterized cohort of 198 APAs. Somatic CTNNB1 mutations were detected in 5.1% of the tumors, occurring mutually exclusive from mutations in KCNJ5, ATP1A1, ATP2B3 and CACNA1D. All of the observed mutations altered serine/threonine residues in the GSK3β binding domain in exon 3. The mutations were associated with stabilized β-catenin and increased AXIN2 expression, suggesting activation of WNT signaling. By CYP11B2 mRNA expression, CYP11B2 protein expression, and direct measurement of aldosterone in tumor tissue, we confirmed the ability for aldosterone production. This report provides compelling evidence that aberrant WNT signaling caused by mutations in CTNNB1 occur in APAs. This also suggests that other mechanisms that constitutively activate the WNT pathway may be important in APA formation. PMID:26815163

  10. Aldosterone-induced glycoproteins: electrophysiological-biochemical correlation.

    PubMed

    Szerlip, H M; Weisberg, L; Geering, K; Rossier, B C; Cox, M

    1988-05-01

    Aldosterone induces the synthesis of a group of glycoproteins (GP65,70) in toad urinary bladders which are potential effectors of the natriferic action of this hormone. In the present study we have confirmed that aldosterone produces a two-phase electrophysiological response. During the early phase (less than 3 h) short-circuit current and transepithelial conductance increase in parallel, while during the late phase (greater than 3 h) short-circuit current continues to increase without any further change in conductance. By biosynthetically labeling aldosterone-treated toad bladders with [35S]methionine either during the early (h 0-2 or 1-3) or the late (h 4-6 or 7-9) phases of the natriferic response, we have demonstrated that GP65,70 is synthesized as a late effect of aldosterone. Since synthesis of GP65,70 occurs at a time when the electromotive force of the Na+ pump is increasing, and since GP65,70 biochemically resembles the beta subunit of Na+/K+-ATPase, studies were undertaken to examine whether GP65,70 is the beta subunit. Purified amphibian renal beta subunit was analyzed by two-dimensional polyacrylamide gel electrophoresis and was found to have an isoelectric point and Mr value similar to those of GP65,70. However, when nitrocellulose blots containing wheat germ agglutinin-purified proteins from aldosterone-treated bladders were stained with monospecific polyclonal antibodies developed against the beta subunit, GP65,70 was not recognized, whereas a group of slightly more acidic proteins of similar Mr were recognized. Thus, GP65,70 is not the beta subunit of Na+/Ka+-ATPase. Further studies are needed to determine the cellular function of GP65,70. PMID:2835098

  11. Stilbene Synthase and Chalcone Synthase 1

    PubMed Central

    Rolfs, Claus-Henning; Kindl, Helmut

    1984-01-01

    Cultured cells of Picea excelsa capable of forming stilbenes and flavanoids have been established. Unlike needles of intact plants containing piceatannol (3,3′,4′,5-tetrahydroxystilbene) and stilbene glycosides the cultured cells converted phenylalanine and p-coumaric acid primarily into resveratrol monomethyl ether (3,4′-dihydroxy-5-methoxystilbene) and naringenin. Partially purified enzyme preparations were assayed for chalcone synthase as well as for stilbene synthase activity converting malonyl-CoA plus p-coumaroyl-CoA into 3,4′,5-trihydroxystilbene (resveratrol). Although stilbene synthase and chalcone synthase use the same substrates and exhibit similar molecular properties, i.e. molecular weight and subunit molecular weight, they are two different proteins. This difference was demonstrated by gel electrophoresis and by means of monospecific antibodies. PMID:16663649

  12. Aldosterone-Induced Vascular Remodeling and Endothelial Dysfunction Require Functional Angiotensin Type 1a Receptors.

    PubMed

    Briet, Marie; Barhoumi, Tlili; Mian, Muhammad Oneeb Rehman; Coelho, Suellen C; Ouerd, Sofiane; Rautureau, Yohann; Coffman, Thomas M; Paradis, Pierre; Schiffrin, Ernesto L

    2016-05-01

    We investigated the role of angiotensin type 1a receptors (AGTR1a) in vascular injury induced by aldosterone activation of mineralocorticoid receptors in Agtr1a(-/-) and wild-type (WT) mice infused with aldosterone for 14 days while receiving 1% NaCl in drinking water. Aldosterone increased systolic blood pressure (BP) by ≈30 mm Hg in WT mice and ≈50 mm Hg in Agtr1a(-/-) mice. Aldosterone induced aortic and small artery remodeling, impaired endothelium-dependent relaxation in WT mice, and enhanced fibronectin and collagen deposition and vascular inflammation. None of these vascular effects were observed in Agtr1a(-/-) mice. Aldosterone effects were prevented by the AGTR1 antagonist losartan in WT mice. In contrast to aldosterone, norepinephrine caused similar BP increase and mesenteric artery remodeling in WT and Agtr1a(-/-) mice. Agtr1a(-/-) mice infused with aldosterone did not increase sodium excretion in response to a sodium chloride challenge, suggesting that sodium retention could contribute to the exaggerated BP rise induced by aldosterone. Agtr1a(-/-) mice had decreased mesenteric artery expression of the calcium-activated potassium channel Kcnmb1, which may enhance myogenic tone and together with sodium retention, exacerbate BP responses to aldosterone/salt in Agtr1a(-/-) mice. We conclude that although aldosterone activation of mineralocorticoid receptors raises BP more in Agtr1a(-/-) mice, AGTR1a is required for mineralocorticoid receptor stimulation to induce vascular remodeling and inflammation and endothelial dysfunction. PMID:27045029

  13. Type I receptors in parotid, colon, and pituitary are aldosterone selective in vivo

    SciTech Connect

    Sheppard, K.; Funder, J.W. )

    1987-10-01

    Previous in vivo studies have demonstrated that type I receptors in the rat kidney are aldosterone selective, whereas those in the hippocampus do not appear to discriminate between aldosterone and corticosterone. The authors have injected mature rats with ({sup 3}H)aldosterone or ({sup 3}H)corticosterone plus 100-fold excess of RU 28362, with or without unlabeled aldosterone or corticosterone, and compared type I receptor occupancy in two classic mineralocorticoid target tissues (parotid and colon) and in the pituitary. Mature rats were killed 10-180 min after tracer administration; ({sup 3}H)aldosterone was well taken up and retained in all tissues, whereas ({sup 3}H)corticosterone was significantly retained only in the pituitary 10 min after tracer administration. To assess a possible role for corticosterone-binding globulin (CBG) in conferring aldosterone specificity on type I receptors, 10-day-old rats (with very low levels of CBG) were similarly injected. In the colon and parotid, ({sup 3}H)aldosterone binding was at least an order of magnitude higher than that of corticosterone; in the pituitary aldosterone binding was approximately three times that of corticosterone. They interpret these data as evidence that in the parotid and colon type I receptors are aldosterone selective by a non-CBG-requiring mechanism, whereas in the pituitary there appear to be both aldosterone-selective and nonselective type I sites.

  14. Effects of aldosterone on transient outward K+ current density in rat ventricular myocytes

    PubMed Central

    Bénitah, Jean-Pierre; Perrier, Emeline; Gómez, Ana María; Vassort, Guy

    2001-01-01

    Aldosterone, a major ionic homeostasis regulator, might also regulate cardiac ion currents. Using the whole-cell patch-clamp technique, we investigated whether aldosterone affects the 4-aminopyridine-sensitive transient outward K+ current (Ito1). Exposure to 100 nm aldosterone for 48 h at 37 °C produced a 1.6-fold decrease in the Ito1 density compared to control myocytes incubated without aldosterone. Neither the time- nor voltage-dependent properties of the current were significantly altered after aldosterone treatment. RU28318 (1 μm), a specific mineralocorticoid receptor antagonist, prevented the aldosterone-induced decrease in Ito1 density. When myocytes were incubated for 24 h with aldosterone, concentrations up to 1 μm did not change Ito1 density, whereas L-type Ca2+ current (ICa,L) density increased. After 48 h, aldosterone caused a further increase in ICa,L. The delay in the Ito1 response to aldosterone might indicate that it occurs secondary to an increase in ICa,L. After 24 h of aldosterone pretreatment, further co-incubation for 24 h either with an ICa,L antagonist (100 nm nifedipine) or with a permeant Ca2+ chelator (10 μm BAPTA-AM) prevented a decrease in Ito1 density. After 48 h of aldosterone treatment, we observed a 2.5-fold increase in the occurrence of spontaneous Ca2+ sparks, which was blunted by co-treatment with nifedipine. We conclude that aldosterone decreases Ito1 density. We suggest that this decrease is secondary to the modulation of intracellular Ca2+ signalling, which probably arises from the aldosterone-induced increase in ICa,L. These results provide new insights into how cardiac ionic currents are modulated by hormones. PMID:11711569

  15. Zero gravity and cardiovascular homeostasis. The relationship between endogenous hyperprolactinemia and plasma aldosterone

    NASA Technical Reports Server (NTRS)

    Haber, E.; Re, R. N.; Kourides, I. A.; Weihl, A. C.; Maloof, F.

    1978-01-01

    Prolactin, thyrotropin and aldosterone were measured by radioimmunoassay and plasma renin activity by the radioimmunoassay of angiotensin I in normal women before and after the intravenous injection of 200 micrograms of thyrotropin releasing hormone. Prolactin increased at 15 minutes following thyrotropin releasing hormone. Plasma renin activity was not different from control levels during the first hour following the administration of thyrotropin releasing hormone, nor did the plasma aldosterone concentration differ significantly from the control levels during this period. However, with upright posture, an increase in aldosterone and in plasma renin activity was noted, demonstrating a normal capacity to secrete aldosterone. Similarly, no change in aldosterone was seen in 9 patients with primary hypothyroidism given thyrotropin releasing hormone, despite the fact that the increase in prolactin was greater than normal. These data demonstrate that acutely or chronically elevated serum prolactin levels do not result in increased plasma aldosterone levels in humans.

  16. Cellulose synthase interacting protein

    PubMed Central

    Somerville, Chris

    2010-01-01

    Cellulose is the most abundant biopolymer on earth. The great abundance of cellulose places it at the forefront as a primary source of biomass for renewable biofuels. However, the knowledge of how plant cells make cellulose remains very rudimentary. Cellulose microfibrils are synthesized at the plasma membrane by hexameric protein complexes, also known as cellulose synthase complexes. The only known components of cellulose synthase complexes are cellulose synthase (CESA) proteins until the recent identification of a novel component. CSI1, which encodes CESA interacting protein 1 (CSI1) in Arabidopsis. CSI1, as the first non-CESA proteins associated with cellulose synthase complexes, opens up many opportunities. PMID:21150290

  17. High prevalence of thyroid ultrasonographic abnormalities in primary aldosteronism.

    PubMed

    Armanini, Decio; Nacamulli, Davide; Scaroni, Carla; Lumachi, Franco; Selice, Riccardo; Fiore, Cristina; Favia, Gennaro; Mantero, Franco

    2003-11-01

    The study was performed to evaluate the prevalence of thyroid abnormalities detected by ultrasonography and, in particular, of multinodular nontoxic goiter in primary aldosteronism. We analyzed 80 consecutive of patients with primary hyperaldosteronism (40 with unilateral adenoma and 40 with idiopathic hyperaldosteronism) and 80 normotensive healthy controls, comparable for age, sex, iodine intake, and geographical area. Blood pressure, thyroid palpation, thyroid function, and ultrasonography were evaluated. The prevalence of ultrasonographic thyroid abnormalities was 60% in primary aldosteronism and 27% in controls (p < 0.0001). There was a statistically significant difference in prevalence of these abnormalities in unilateral adenoma and idiopathic hyperaldosteronism with respect to controls (p < 0.05 and p < 0.0001, respectively). The prevalence of multinodular nontoxic goiter in idiopathic hyperaldosteronism was higher than in controls (p < 0.001) and, in particular, in female patients. From these data it seems to be worth considering the existence of primary hyperaldosteronism in patients with multinodular goiter and hypertension. PMID:14665720

  18. Roles of aldosterone in vascular calcification: An update.

    PubMed

    Gao, Jingwei; Zhang, Kun; Chen, Jie; Wang, Mong-Heng; Wang, Jingfeng; Liu, Pinming; Huang, Hui

    2016-09-01

    Both clinical and experimental studies have demonstrated that vascular calcification (VC) is a common pathology shared in many chronic diseases such as chronic kidney disease (CKD) and diabetes. It's an independent risk factor for cardiovascular events. Since the pathogenesis of VC is complicated, current therapies have limited effects on the regression of VC. Therefore, it is urgent to investigate the potential mechanisms and find new targets for the treatment of VC. Aldosterone (Aldo), a mineralocorticoid hormone, is the metabolite of renin-angiotensin-aldosterone system (RAAS) activation, which can exert genomic and non-genomic effects on the cardiovascular system. Recent data suggests that Aldo can promote VC. Here, we summarized the roles of Aldo in the process of VC and a series of findings indicated that Aldo could act as a potentially therapeutic target for treating VC. PMID:27238972

  19. Renin and aldosterone measurements in the management of arterial hypertension.

    PubMed

    Viola, A; Monticone, S; Burrello, J; Buffolo, F; Lucchiari, M; Rabbia, F; Williams, T A; Veglio, F; Mengozzi, G; Mulatero, P

    2015-06-01

    Renin-angiotensin-aldosterone system (RAAS) is recognized as the main regulatory system of hemodynamics in man, and its derangements have a key role in the development and maintenance of arterial hypertension. Classification of the hypertensive states according to different patterns of renin and aldosterone levels ("RAAS profiling") allows the diagnosis of specific forms of secondary hypertension and may identify distinct hemodynamic subsets in essential hypertension. In this review, we summarize the application of RAAS profiling for the diagnostic assessment of hypertensive patients and discuss how the pathophysiological framework provided by RAAS profiling may guide therapeutic decision-making, especially in the context of uncontrolled hypertension not responding to multi-therapy. PMID:25993253

  20. SFE/SFHTA/AFCE primary aldosteronism consensus: Introduction and handbook.

    PubMed

    Amar, Laurence; Baguet, Jean Philippe; Bardet, Stéphane; Chaffanjon, Philippe; Chamontin, Bernard; Douillard, Claire; Durieux, Pierre; Girerd, Xaxier; Gosse, Philippe; Hernigou, Anne; Herpin, Daniel; Houillier, Pascal; Jeunemaitre, Xavier; Joffre, Francis; Kraimps, Jean-Louis; Lefebvre, Hervé; Ménégaux, Fabrice; Mounier-Véhier, Claire; Nussberger, Juerg; Pagny, Jean-Yves; Pechère, Antoinette; Plouin, Pierre-François; Reznik, Yves; Steichen, Olivier; Tabarin, Antoine; Zennaro, Maria-Christina; Zinzindohoue, Franck; Chabre, Olivier

    2016-07-01

    The French Endocrinology Society (SFE) French Hypertension Society (SFHTA) and Francophone Endocrine Surgery Association (AFCE) have drawn up recommendations for the management of primary aldosteronism (PA), based on an analysis of the literature by 27 experts in 7 work-groups. PA is suspected in case of hypertension associated with one of the following characteristics: severity, resistance, associated hypokalemia, disproportionate target organ lesions, or adrenal incidentaloma with hypertension or hypokalemia. Diagnosis is founded on aldosterone/renin ratio (ARR) measured under standardized conditions. Diagnostic thresholds are expressed according to the measurement units employed. Diagnosis is established for suprathreshold ARR associated with aldosterone concentrations >550pmol/L (200pg/mL) on 2 measurements, and rejected for aldosterone concentration<240pmol/L (90pg/mL) and/or subthreshold ARR. The diagnostic threshold applied is different if certain medication cannot be interrupted. In intermediate situations, dynamic testing is performed. Genetic forms of PA are screened for in young subjects and/or in case of familial history. The patient should be informed of the results expected from medical and surgical treatment of PA before exploration for lateralization is proposed. Lateralization is explored by adrenal vein sampling (AVS), except in patients under 35 years of age with unilateral adenoma on imaging. If PA proves to be lateralized, unilateral adrenalectomy may be performed, with adaptation of medical treatment pre- and postoperatively. If PA is non-lateralized or the patient refuses surgery, spironolactone is administered as first-line treatment, replaced by amiloride, eplerenone or calcium-channel blockers if insufficiently effective or poorly tolerated. PMID:27315757

  1. Overview of the genetic determinants of primary aldosteronism

    PubMed Central

    Al-Salameh, Abdallah; Cohen, Régis; Desailloud, Rachel

    2014-01-01

    Primary aldosteronism is the most common cause of secondary hypertension. The syndrome accounts for 10% of all cases of hypertension and is primarily caused by bilateral adrenal hyperplasia or aldosterone-producing adenoma. Over the last few years, the use of exome sequencing has significantly improved our understanding of this syndrome. Somatic mutations in the KCNJ5, ATP1A1, ATP2B3 or CACNA1D genes are present in more than half of all cases of aldosterone-producing adenoma (~40%, ~6%, ~1% and ~8%, respectively). Germline gain-of-function mutations in KCNJ5 are now known to cause familial hyperaldosteronism type III, and an additional form of genetic hyperaldosteronism has been reported in patients with germline mutations in CACNA1D. These genes code for channels that control ion homeostasis across the plasma membrane of zona glomerulosa cells. Moreover, all these mutations modulate the same pathway, in which elevated intracellular calcium levels lead to aldosterone hyperproduction and (in some cases) adrenal cell proliferation. From a clinical standpoint, the discovery of these mutations has potential implications for patient management. The mutated channels could be targeted by drugs, in order to control hormonal and overgrowth-related manifestations. Furthermore, some of these mutations are associated with high cell turnover and may be amenable to diagnosis via the sequencing of cell-free (circulating) DNA. However, genotype-phenotype correlations in patients harboring these mutations have yet to be characterized. Despite this recent progress, much remains to be done to elucidate the yet unknown mechanisms underlying sporadic bilateral adrenal hyperplasia. PMID:24817817

  2. Time-dependent aldosterone metabolism in toad urinary bladder

    SciTech Connect

    Brem, A.S.; Pacholski, M.; Morris, D.J.

    1988-04-01

    Aldosterone (Aldo) metabolism was examined in the toad bladder. Bladders were incubated with (/sup 3/H)aldosterone (10(-7) M) for 5 h, 1 h, or 10 min. Tissues were analyzed for metabolites using high-pressure liquid chromatography (HPLC). In separate experiments, Na+ transport was assessed by the short-circuit current (SCC) technique. Following a 5-h tissue incubation, about 25% of the (/sup 3/H)-aldosterone was converted into metabolites including a polar monosulfate metabolite, 20 beta-dihydroaldo (20 beta-DHAldo), small quantities of 5 beta-reduced products, and a variety of 5 alpha-reduced Aldo products including 5 alpha-DHAldo, 3 alpha,5 alpha-tetrahydroaldo (3 alpha,5 alpha-THAldo), and 3 beta,5 alpha-THAldo. Tissues metabolized approximately 10% of the labeled hormone into the same compounds by 1 h. Measurable quantities of these metabolites were also synthesized by bladders exposed to Aldo for only 10 min and then incubated in buffer for an additional 50 min without Aldo. Bladders pretreated with the spironolactone, K+-canrenoate (3.5 X 10(-4) M), and stimulated with Aldo (10(-7) M) generated a peak SCC 44 +/- 6% of that observed in matched pairs stimulated with Aldo (P less than 0.001; n = 6). K+-canrenoate also markedly diminished (/sup 3/H)aldosterone metabolism at both 5 and 1 h. Thus, metabolic transformation of Aldo begins prior to hormone-induced increases in Na+ transport. Both the generation of certain metabolites (e.g., 5 alpha-reductase pathway products) and the increase in Na+ transport can be selectively inhibited by K+-canrenoate.

  3. Physiological techniques in the study of rapid aldosterone effects.

    PubMed

    Yusef, Yamil R; Thomas, Warren; Harvey, Brian J

    2014-01-01

    Molecular imaging and electrophysiological techniques are powerful tools to analyze the responses stimulated by aldosterone and other hormones in target tissues. Studies with Ussing-type chambers can be used to measure and characterize changes in transepithelial currents resulting from hormone treatment. Confocal imaging techniques can be used in real time or in fixed preparations to evaluate the localization of receptors, signalling intermediates, and transporters. PMID:25182774

  4. Bartter Syndrome with Normal Aldosterone Level: An Unusual Presentation.

    PubMed

    Huque, S S; Rahman, M H; Khatun, S

    2016-04-01

    Bartter syndrome (BS) is a hereditary disease, with an autosomal recessive or autosomal dominant mode of transmission. It is characterized by salt wasting hypochloraemic, hypokalaemic metabolic alkalosis and hyperreninaemia with normal blood pressure. The primary defect is in the thick ascending limb of loop of Henle (TAL). Herein, we report a case that had typical features of BS like severe dehydration, severe hypokalaemia, metabolic alkalosis and failure to thrive but had normal aldosterone level which is very uncommon. PMID:27277374

  5. Plasma aldosterone and sweat sodium concentrations after exercise and heat acclimation

    NASA Technical Reports Server (NTRS)

    Kirby, C. R.; Convertino, V. A.

    1986-01-01

    The relationship between plasma aldosterone levels and sweat sodium excretion after chronic exercise and heat acclimation was investigated, using subjects exercised, at 40 C and 45 percent humidity, for 2 h/day on ten consecutive days at 45 percent of their maximal oxygen uptake. The data indicate that, following heat acclimation, plasma aldosterone concentrations decrease, and that the eccrine gland responsiveness to aldosterone, as represented by sweat sodium reabsorption, may be augmented through exercise and heat acclimation.

  6. Cortisol and aldosterone comparisons of cottontail rabbits collected by shooting, trapping, and falconry.

    PubMed

    Hamilton, G D; Weeks, H P

    1985-01-01

    Cortisol and aldosterone levels were measured in plasma of eastern cottontail rabbits (Sylvilagus floridanus) collected by three different methods, i.e., shooting, live-trapping and falconry. Cortisol levels ranged from near 0 to 27.5 micrograms/100 ml and aldosterone from near 0 to 220 ng/100 ml. Shot animals had significantly lower cortisol concentrations than those taken by either of the other methods. Trapped cottontails also had significantly lower aldosterone levels. PMID:3981742

  7. Regulation of aldosterone secretion by Cav1.3.

    PubMed

    Xie, Catherine B; Haris Shaikh, Lalarukh; Garg, Sumedha; Tanriver, Gizem; Teo, Ada E D; Zhou, Junhua; Maniero, Carmela; Zhao, Wanfeng; Kang, Soosung; Silverman, Richard B; Azizan, Elena A B; Brown, Morris J

    2016-01-01

    Aldosterone-producing adenomas (APAs) vary in phenotype and genotype. Zona glomerulosa (ZG)-like APAs frequently have mutations of an L-type calcium channel (LTCC) CaV1.3. Using a novel antagonist of CaV1.3, compound 8, we investigated the role of CaV1.3 on steroidogenesis in the human adrenocortical cell line, H295R, and in primary human adrenal cells. This investigational drug was compared with the common antihypertensive drug nifedipine, which has 4.5-fold selectivity for the vascular LTCC, CaV1.2, over CaV1.3. In H295R cells transfected with wild-type or mutant CaV1.3 channels, the latter produced more aldosterone than wild-type, which was ameliorated by 100 μM of compound 8. In primary adrenal and non-transfected H295R cells, compound 8 decreased aldosterone production similar to high concentration of nifedipine (100 μM). Selective CaV1.3 blockade may offer a novel way of treating primary hyperaldosteronism, which avoids the vascular side effects of CaV1.2-blockade, and provides targeted treatment for ZG-like APAs with mutations of CaV1.3. PMID:27098837

  8. Biological determinants of aldosterone-induced cardiac fibrosis in rats.

    PubMed

    Robert, V; Silvestre, J S; Charlemagne, D; Sabri, A; Trouvé, P; Wassef, M; Swynghedauw, B; Delcayre, C

    1995-12-01

    To determine the events leading to cardiac fibrosis in aldosterone-salt hypertensive rats, we studied protein and mRNA accumulation of procollagens I and III for 60 days. After 3 and 7 days of treatment systolic pressure was normal, and no histological or biochemical changes were seen in rat hearts. At day 15 arterial pressure was raised (+40%) and left ventricular hypertrophy was +15%. Cardiac examination after hemalun-eosin staining and immunolabeling with anticollagen I and III antibodies showed no structural alterations, but an 83% increase in right ventricular type III procollagen mRNA levels was found. At 30 and 60 days we found progressive cardiac fibrosis, with inflammatory cells, myocyte necrosis, and elevation of both types I and III procollagen mRNA levels in both ventricles. To determine whether aldosterone had effects on Na,K-ATPase that might lead to ionic disturbances and induce myocyte necrosis, we studied the major cardiac Na,K-ATPase isoform genes. Although Na,K-ATPase alpha 1- and beta 1-subunit mRNA levels were elevated in kidney at day 1, neither of these cardiac transcripts nor the specific alpha 2 isoform was altered between 1 and 15 days. These results show that accumulation of procollagen mRNAs occurs before collagen deposition. Cardiac alterations are late and not preceded by changes in Na,K-ATPase cardiac gene expression, precluding a direct modulation of cardiac collagen synthesis and Na,K-ATPase by aldosterone. PMID:7490157

  9. Regulation of aldosterone secretion by Cav1.3

    PubMed Central

    Xie, Catherine B.; Haris Shaikh, Lalarukh; Garg, Sumedha; Tanriver, Gizem; Teo, Ada E. D.; Zhou, Junhua; Maniero, Carmela; Zhao, Wanfeng; Kang, Soosung; Silverman, Richard B.; Azizan, Elena A. B.; Brown, Morris J.

    2016-01-01

    Aldosterone-producing adenomas (APAs) vary in phenotype and genotype. Zona glomerulosa (ZG)-like APAs frequently have mutations of an L-type calcium channel (LTCC) CaV1.3. Using a novel antagonist of CaV1.3, compound 8, we investigated the role of CaV1.3 on steroidogenesis in the human adrenocortical cell line, H295R, and in primary human adrenal cells. This investigational drug was compared with the common antihypertensive drug nifedipine, which has 4.5-fold selectivity for the vascular LTCC, CaV1.2, over CaV1.3. In H295R cells transfected with wild-type or mutant CaV1.3 channels, the latter produced more aldosterone than wild-type, which was ameliorated by 100 μM of compound 8. In primary adrenal and non-transfected H295R cells, compound 8 decreased aldosterone production similar to high concentration of nifedipine (100 μM). Selective CaV1.3 blockade may offer a novel way of treating primary hyperaldosteronism, which avoids the vascular side effects of CaV1.2-blockade, and provides targeted treatment for ZG-like APAs with mutations of CaV1.3. PMID:27098837

  10. Aldosterone acutely stimulates NCC activity via a SPAK-mediated pathway

    PubMed Central

    Mistry, Abinash C.; Hanson, Lauren; Mallick, Rickta; Wynne, Brandi M.; Thai, Tiffany L.; Bailey, James L.; Klein, Janet D.; Hoover, Robert S.

    2013-01-01

    Hypertension is a leading cause of morbidity and mortality worldwide, and disordered sodium balance has long been implicated in its pathogenesis. Aldosterone is perhaps the key regulator of sodium balance and thus blood pressure. The sodium chloride cotransporter (NCC) in the distal convoluted tubule of the kidney is a major site of sodium reabsorption and plays a key role in blood pressure regulation. Chronic exposure to aldosterone increases NCC protein expression and function. However, more acute effects of aldosterone on NCC are unknown. In our salt-abundant modern society where chronic salt deprivation is rare, understanding the acute effects of aldosterone is critical. Here, we examined the acute effects (12–36 h) of aldosterone on NCC in the rodent kidney and in a mouse distal convoluted tubule cell line. Studies demonstrated that aldosterone acutely stimulated NCC activity and phosphorylation without affecting total NCC abundance or surface expression. This effect was dependent upon the presence of the mineralocorticoid receptor and serum- and glucocorticoid-regulated kinase 1 (SGK1). Furthermore, STE20/SPS-1-related proline/alanine-rich kinase (SPAK) phosphorylation also increased, and gene silencing of SPAK eliminated the effect of aldosterone on NCC activity. Aldosterone administration via a minipump in adrenalectomized rodents confirmed an increase in NCC phosphorylation without a change in NCC total protein. These data indicate that acute aldosterone-induced SPAK-dependent phosphorylation of NCC increases individual transporter activity. PMID:23739593

  11. Postural plasma aldosterone response in "upright hyperkalemia" associated with selective hypoaldosteronism.

    PubMed

    Rado, J P; Simatupang, T; Boer, P; Dorhout Mees, E J

    1977-07-01

    Upright posture induced a consistent increase in serum K with a blunted plasma aldosterone response in four male renal patients with selective hypoaldosteronism. Dietary Na restriction induced a dramatic increase in the suppressed plasma aldosterone without returning the elevated serum K levels to normal and abolishing the postural serum K change. Therefore it is concluded that "upright hyperkalemia" may not be caused exclusively by suppression or/and inadequate postural response of aldosterone. Cellular disturbance in the regulation of K distribution might be an additional explantation for the aldosterone unresponsive postural K change. PMID:907798

  12. Reverse remodeling and recovery from cachexia in rats with aldosteronism.

    PubMed

    Cheema, Yaser; Zhao, Wenyuan; Zhao, Tieqiang; Khan, M Usman; Green, Kelly D; Ahokas, Robert A; Gerling, Ivan C; Bhattacharya, Syamal K; Weber, Karl T

    2012-08-15

    The congestive heart failure (CHF) syndrome with soft tissue wasting, or cachexia, has its pathophysiologic origins rooted in neurohormonal activation. Mechanical cardiocirculatory assistance reveals the potential for reverse remodeling and recovery from CHF, which has been attributed to device-based hemodynamic unloading whereas the influence of hormonal withdrawal remains uncertain. This study addresses the signaling pathways induced by chronic aldosteronism in normal heart and skeletal muscle at organ, cellular/subcellular, and molecular levels, together with their potential for recovery (Recov) after its withdrawal. Eight-week-old male Sprague-Dawley rats were examined at 4 wk of aldosterone/salt treatment (ALDOST) and following 4-wk Recov. Compared with untreated, age-/sex-/strain-matched controls, ALDOST was accompanied by 1) a failure to gain weight, reduced muscle mass with atrophy, and a heterogeneity in cardiomyocyte size across the ventricles, including hypertrophy and atrophy at sites of microscopic scarring; 2) increased cardiomyocyte and mitochondrial free Ca(2+), coupled to oxidative stress with increased H(2)O(2) production and 8-isoprostane content, and increased opening potential of the mitochondrial permeability transition pore; 3) differentially expressed genes reflecting proinflammatory myocardial and catabolic muscle phenotypes; and 4) reversal to or toward recovery of these responses with 4-wk Recov. Aldosteronism in rats is accompanied by cachexia and leads to an adverse remodeling of the heart and skeletal muscle at organ, cellular/subcellular, and molecular levels. However, evidence presented herein implicates that these tissues retain their inherent potential for recovery after complete hormone withdrawal. PMID:22730385

  13. Reverse remodeling and recovery from cachexia in rats with aldosteronism

    PubMed Central

    Cheema, Yaser; Zhao, Wenyuan; Zhao, Tieqiang; Khan, M. Usman; Green, Kelly D.; Ahokas, Robert A.; Gerling, Ivan C.; Bhattacharya, Syamal K.

    2012-01-01

    The congestive heart failure (CHF) syndrome with soft tissue wasting, or cachexia, has its pathophysiologic origins rooted in neurohormonal activation. Mechanical cardiocirculatory assistance reveals the potential for reverse remodeling and recovery from CHF, which has been attributed to device-based hemodynamic unloading whereas the influence of hormonal withdrawal remains uncertain. This study addresses the signaling pathways induced by chronic aldosteronism in normal heart and skeletal muscle at organ, cellular/subcellular, and molecular levels, together with their potential for recovery (Recov) after its withdrawal. Eight-week-old male Sprague-Dawley rats were examined at 4 wk of aldosterone/salt treatment (ALDOST) and following 4-wk Recov. Compared with untreated, age-/sex-/strain-matched controls, ALDOST was accompanied by 1) a failure to gain weight, reduced muscle mass with atrophy, and a heterogeneity in cardiomyocyte size across the ventricles, including hypertrophy and atrophy at sites of microscopic scarring; 2) increased cardiomyocyte and mitochondrial free Ca2+, coupled to oxidative stress with increased H2O2 production and 8-isoprostane content, and increased opening potential of the mitochondrial permeability transition pore; 3) differentially expressed genes reflecting proinflammatory myocardial and catabolic muscle phenotypes; and 4) reversal to or toward recovery of these responses with 4-wk Recov. Aldosteronism in rats is accompanied by cachexia and leads to an adverse remodeling of the heart and skeletal muscle at organ, cellular/subcellular, and molecular levels. However, evidence presented herein implicates that these tissues retain their inherent potential for recovery after complete hormone withdrawal. PMID:22730385

  14. Endocrine effects of lithium. III. Hypermagnesaemia and activation of the renin-aldosterone system.

    PubMed

    Transbøl, I; Christiansen, C; Baastrup, P C; Nielsen, M D; Giese, J

    1978-07-01

    Hypermagnesaemia is a well-known but as yet unexplained concomitant of lithium treatment. Prior suggestions implicating a role for aldosterone in magnesium homoeostasis prompted this study of plasma renin, plasma aldosterone and serum magnesium in 17 maniodepressive patients on long-term lithium treatment. In addition to hypermagnesaemia (P less than 0.001), this group of patients had raised plasma levels of aldosterone (P less than 0.001) and increased plasma renin concentration (P less than 0.05). Serum magnesium was positively correlated to plasma aldosterone (r = 0.58, P less than 0.02). The relation between activation of the renin-aldosterone system and the presence of hypermagnesaemia during chronic lithium treatment could conceivably be mediated through a lithium-induced hypovolaemic state. PMID:581026

  15. Adrenal Venous Sampling in Patients With Positive Screening but Negative Confirmatory Testing for Primary Aldosteronism.

    PubMed

    Umakoshi, Hironobu; Naruse, Mitsuhide; Wada, Norio; Ichijo, Takamasa; Kamemura, Kohei; Matsuda, Yuichi; Fujii, Yuichi; Kai, Tatsuya; Fukuoka, Tomikazu; Sakamoto, Ryuichi; Ogo, Atsushi; Suzuki, Tomoko; Nanba, Kazutaka; Tsuiki, Mika

    2016-05-01

    Adrenal venous sampling is considered to be the most reliable diagnostic procedure to lateralize aldosterone excess in primary aldosteronism (PA). However, normative criteria have not been established partially because of a lack of data in non-PA hypertensive patients. The aim of the study was to investigate aldosterone concentration and its gradient in the adrenal vein of non-PA hypertensive patients. We retrospectively studied the results of cosyntropin-stimulated adrenal venous sampling in 40 hypertensive patients who showed positive screening testing but negative results in 2 confirmatory tests/captopril challenge test and saline infusion test. Plasma aldosterone concentration, aldosterone/cortisol ratio, its higher/lower ratio (lateralization index) in the adrenal vein with cosyntropin stimulation were measured. Median plasma aldosterone concentration in the adrenal vein was 25 819 pg/mL (range, 5154-69 920) in the higher side and 12 953 (range, 1866-36 190) pg/mL in the lower side (P<0.001). There was a significant gradient in aldosterone/cortisol ratio between the higher and the lower sides (27.2 [5.4-66.0] versus 17.3 [4.0-59.0] pg/mL per μg/dL;P<0.001) with lateralization index ranging from 1.01 to 3.87. The aldosterone lateralization gradient was between 1 to 2 in 32 patients and 2 to 4 in 8 patients. None of the patients showed lateralization index ≥4. The present study demonstrated that plasma aldosterone concentration in the adrenal veins showed significant variation and lateralization gradient even in non-PA hypertensive patients. Adrenal venous sampling aldosterone lateralization gradients between 2 and 4 should be interpreted with caution in patients with PA because these gradients can be found even in patients with negative confirmatory testing for PA. PMID:26975712

  16. Aldosterone and thyroid hormone interaction on the sodium and potassium transport pathways of rat colonic epithelium.

    PubMed

    Edmonds, C J; Willis, C L

    1990-01-01

    The effect of hypothyroidism on potassium adaptation (shown by increased potassium secretion in response to potassium loading) and on the action of aldosterone on potassium secretion and sodium fluxes was examined in the rat distal colon. Potassium adaptation, particularly the response to an acute potassium load, was impaired by hypothyroidism which also considerably reduced the rise of transepithelial electrical potential difference (p.d.) of total and transcellular (active) lumen-to-plasma sodium fluxes and of potassium secretion normally produced by aldosterone. These changes were, in part, corrected by a short period (3 days) of tri-iodothyronine replacement. Moreover in aldosterone-treated hypothyroid rats, amiloride in the lumen was considerably less effective in reducing the p.d. and sodium fluxes than in aldosterone-treated normal rats. The intracellular sodium transport pool was greater in the hypothyroid than in the normal rats (5.0 +/- 1.1 (S.E.M.) nmol/mg dry weight compared with 2.9 +/- 0.2 nmol/mg dry weight; P less than 0.02). Aldosterone increased the pool in the normal but not in the hypothyroid rats while amiloride had little effect on the pool in the aldosterone-treated hypothyroid rats but almost abolished it in aldosterone-treated normal rats. Aldosterone plays a major part in the adaptation of colonic sodium and potassium transport to sodium depletion or potassium excess; these adaptations were much impaired in hypothyroid animals. The present results are consistent with a deficiency in aldosterone induction of potassium- and amiloride-sensitive sodium pathways in the apical membrane of colonic epithelial cells in hypothyroid rats, a deficiency which limits the stimulant effect of aldosterone on sodium and potassium transport. PMID:2299278

  17. Idiopathic primary hyperaldosteronism: normalization of plasma aldosterone after one month withdrawal of long-term therapy with aldosterone-receptor antagonist potassium canrenoate.

    PubMed

    Armanini, D; Scaroni, C; Mattarello, M J; Fiore, C; Albiger, N; Sartorato, P

    2005-03-01

    We have re-evaluated 15 patients with idiopathic primary aldosteronism one month after withdrawal of therapy with aldosterone-receptor antagonist potassium canrenoate. Therapy had lasted for 3 to 24 yr. Median blood pressure (BP) in the sitting position at the time of diagnosis was 160/100 (ranges 150-200/95-110 mmHg); while 1 month after withdrawal of therapy median BP was 145/90 (ranges 125-160/80-100 mmHg). One month after withdrawal, the ratio aldosterone (ng/dl)/plasma renin activity (ng/ml/h) in the upright position was increased only in 3 cases (median 18, range 6.1-125). We found a significant inverse correlation between the upright aldosterone/plasma renin activity (aldo/PRA) ratio, 1 month after withdrawal, and the number of years of therapy with potassium canrenoate. We conclude that long-term therapy with the aldosterone-receptor blocker, potassium canrenoate, can normalize the aldo/PRA ratio in many cases of idiopathic primary hyperaldosteronism after one-month withdrawal of the drug. These data are consistent with possible regression of idiopathic primary hyperaldosteronism after long-term therapy with potassium canrenoate, or in alternative to a persistent effect of potassium canrenoate, on aldosterone synthesis. PMID:15952408

  18. mPGES-1 deletion impairs aldosterone escape and enhances sodium appetite

    PubMed Central

    Jia, Zhanjun; Aoyagi, Toshinori; Kohan, Donald E.

    2010-01-01

    Aldosterone (Aldo) is a major sodium-retaining hormone that reduces renal sodium excretion and also stimulates sodium appetite. In the face of excess Aldo, the sodium-retaining action of this steroid is overridden by an adaptive regulatory mechanism, a phenomenon termed Aldo escape. The underlying mechanism of this phenomenon is not well defined but appeared to involve a number of natriuretic factors such prostaglandins (PGs). Here, we investigated the role of microsomal prostaglandin E synthase-1 (mPGES-1) in the response to excess Aldo. A 14-day Aldo infusion at 0.35 mg·kg−1·day−1 via an osmotic minipump in conjunction with normal salt intake did not produce obvious disturbances in fluid metabolism in WT mice as suggested by normal sodium and water balance, plasma sodium concentration, hematocrit, and body weight, despite the evidence of a transient sodium accumulation on days 1 or 2. In a sharp contrast, the 14-day Aldo treatment in mPGES-1 knockoute (KO) mice led to increased sodium and water balance, persistent reduction of hematocrit, hypernatremia, and body weight gain, all evidence of fluid retention. The escaped wild-type (WT) mice displayed a remarkable increase in urinary PGE2 excretion in parallel with coinduction of mPGES-1 in the proximal tubules, accompanied by a remarkable, widespread downregulation of renal sodium and water transporters. The increase in urinary PGE2 excretion together with the downregulation of renal sodium and water transporters were all significantly blocked in the KO mice. Interestingly, compared with WT controls, the KO mice exhibited consistent increases in sodium and water intake during Aldo infusion. Together, these results suggest an important role of mPGES-1 in antagonizing the sodium-retaining action of Aldo at the levels of both the central nervous system and the kidney. PMID:20335314

  19. Time to retrieve the best benefits from renin angiotensin aldosterone system (RAAS) inhibition in heart failure patients with reduced ejection fraction: lessons from randomized controlled trials and registries.

    PubMed

    Rossignol, Patrick; Zannad, Faiez; Pitt, Bertram

    2014-12-20

    Numerous registries, including the most recent ESC Euro-observational registry, have reported a large and persistent gap between real-life practice in the use of life-saving evidence-based therapies (such as renin angiotensin antagonists, beta-blockers, mineralocorticoid receptor antagonists) and recommended practices in international guidelines. Although the use of multiple renin angiotensin aldosterone system-inhibitors is associated with the development of worsening renal function and hyperkalemia in patients with heart failure and reduced ejection fraction, increased efforts should be expended to initiate and maintain target doses of these agents so as to provide their benefits on mortality and hospitalizations for heart failure. PMID:25465821

  20. Role of Renin-Angiotensin-Aldosterone System in Metabolic Syndrome and Obesity-related Hypertension.

    PubMed

    Kamide, K

    2014-08-12

    outcomes with treatment to a goal SBP <150 mm Hg, but no randomized controlled trials support a goal <140/90 mm Hg. Despite this, the panel opted for a conservative recommendation in patients with diabetes and hypertension, opting for a goal level of <140/90 mm Hg in adult patients with diabetes and hypertension rather than the evidence based goal of <150/90 mm Hg [3, 5]. JSH-2014 recommends that the first choice of antihypertensive medication should be RAAS blockers such as ACE inhibitor or ARB. For the last several years, several large cohort clinical studies using ACEI and ARB have shown more favorable effects, but aldosterone receptor inhibitor (mineral corticoid receptor inhibitors; MR inhibitors) and Renin Inhibitors have been withdrawn. Some studies showed the strong support to use these medications for diabetic patients. This review will discuss the relationships between vascular RAAS and insulin resistance in patients with hypertension and diabetes as previously reviewed with new updated findings for the last 4 years, and clinical implications based on updated JNC-8, ESH-ESC2013 and JSH-2014. PMID:25115697

  1. Therapeutic effect of enhancing endothelial nitric oxide synthase (eNOS) expression and preventing eNOS uncoupling

    PubMed Central

    Förstermann, Ulrich; Li, Huige

    2011-01-01

    Nitric oxide (NO) produced by the endothelium is an important protective molecule in the vasculature. It is generated by the enzyme endothelial NO synthase (eNOS). Similar to all NOS isoforms, functional eNOS transfers electrons from nicotinamide adenine dinucleotide phosphate (NADPH), via the flavins flavin adenine dinucleotide and flavin mononucleotide in the carboxy-terminal reductase domain, to the heme in the amino-terminal oxygenase domain. Here, the substrate L-arginine is oxidized to L-citrulline and NO. Cardiovascular risk factors such as diabetes mellitus, hypertension, hypercholesterolaemia or cigarette smoking reduce bioactive NO. These risk factors lead to an enhanced production of reactive oxygen species (ROS) in the vessel wall. NADPH oxidases represent major sources of this ROS and have been found upregulated in the presence of cardiovascular risk factors. NADPH-oxidase-derived superoxide avidly reacts with eNOS-derived NO to form peroxynitrite (ONOO-). The essential NOS cofactor (6R-)5,6,7,8-tetrahydrobiopterin (BH4) is highly sensitive to oxidation by this ONOO-. In BH4 deficiency, oxygen reduction uncouples from NO synthesis, thereby converting NOS to a superoxide-producing enzyme. Among conventional drugs, compounds interfering with the renin-angiotensin-aldosterone system and statins can reduce vascular oxidative stress and increase bioactive NO. In recent years, we have identified a number of small molecules that have the potential to prevent eNOS uncoupling and, at the same time, enhance eNOS expression. These include the protein kinase C inhibitor midostaurin, the pentacyclic triterpenoids ursolic acid and betulinic acid, the eNOS enhancing compounds AVE9488 and AVE3085, and the polyphenolic phytoalexin trans-resveratrol. Such compounds enhance NO production from eNOS also under pathophysiological conditions and may thus have therapeutic potential. PMID:21198553

  2. Long term outcome of Aldosteronism after target treatments.

    PubMed

    Wu, Vin-Cent; Wang, Shuo-Meng; Chang, Chia-Hui; Hu, Ya-Hui; Lin, Lian-Yu; Lin, Yen-Hung; Chueh, Shih-Chieh Jeff; Chen, Likwang; Wu, Kwan-Dun

    2016-01-01

    There exists a great knowledge gap in terms of long-term effects of various surgical and pharmacological treatments on outcomes among primary aldosteronism (PA) patients. Using a validated algorithm, we extracted longitudinal data for all PA patients diagnosed in 1997-2010 and treated in the Taiwan National Health Insurance. We identified 3362 PA patients for whom the mean length of follow-up was 5.75 years. PA has higher major cardiovascular events (MACE) than essential hypertension (23.3% vs 19.3%, p = 0.015). Results from the Cox model suggest a strong effect of adrenalectomy on lowering mortality (HR = 0.23 with residual hypertension and 0.21 with resolved hypertension). While need for receptor antagonist (MRA) MRA after diagnosis suggests that a defined daily dose (DDD) of MRA between 12.5 and 50 mg may alleviate risk of death in a U-shape pattern. A specificity test identified patients who has aldosterone producing adenoma (HR = 0.50, p = 0.005) also confirmed adrenalectomy attenuated all-cause mortality. Adrenalectomy decreases long-term all-cause mortality independently from PA cure from hypertension. Prescription corresponding to a DDD between 12.5 and 50 mg may decrease mortality for patients needing MRA. It calls for more attention on early diagnosis, early treatment and prescription of appropriate dosage of MRA for PA patients. PMID:27586402

  3. Long term outcome of Aldosteronism after target treatments

    PubMed Central

    Wu, Vin-Cent; Wang, Shuo-Meng; Chang, Chia-Hui; Hu, Ya-Hui; Lin, Lian-Yu; Lin, Yen-Hung; Chueh, Shih-Chieh Jeff; Chen, Likwang; Wu, Kwan-Dun

    2016-01-01

    There exists a great knowledge gap in terms of long-term effects of various surgical and pharmacological treatments on outcomes among primary aldosteronism (PA) patients. Using a validated algorithm, we extracted longitudinal data for all PA patients diagnosed in 1997–2010 and treated in the Taiwan National Health Insurance. We identified 3362 PA patients for whom the mean length of follow-up was 5.75 years. PA has higher major cardiovascular events (MACE) than essential hypertension (23.3% vs 19.3%, p = 0.015). Results from the Cox model suggest a strong effect of adrenalectomy on lowering mortality (HR = 0.23 with residual hypertension and 0.21 with resolved hypertension). While need for receptor antagonist (MRA) MRA after diagnosis suggests that a defined daily dose (DDD) of MRA between 12.5 and 50 mg may alleviate risk of death in a U-shape pattern. A specificity test identified patients who has aldosterone producing adenoma (HR = 0.50, p = 0.005) also confirmed adrenalectomy attenuated all-cause mortality. Adrenalectomy decreases long-term all-cause mortality independently from PA cure from hypertension. Prescription corresponding to a DDD between 12.5 and 50 mg may decrease mortality for patients needing MRA. It calls for more attention on early diagnosis, early treatment and prescription of appropriate dosage of MRA for PA patients. PMID:27586402

  4. TRAF3IP2 mediates aldosterone/salt-induced cardiac hypertrophy and fibrosis.

    PubMed

    Sakamuri, Siva S V P; Valente, Anthony J; Siddesha, Jalahalli M; Delafontaine, Patrice; Siebenlist, Ulrich; Gardner, Jason D; Bysani, Chandrasekar

    2016-07-01

    Aberrant activation of the renin-angiotensin-aldosterone system (RAAS) contributes to adverse cardiac remodeling and eventual failure. Here we investigated whether TRAF3 Interacting Protein 2 (TRAF3IP2), a redox-sensitive cytoplasmic adaptor molecule and an upstream regulator of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), mediates aldosterone-induced cardiac hypertrophy and fibrosis. Wild type (WT) and TRAF3IP2-null mice were infused with aldosterone (0.2 mg/kg/day) for 4 weeks along with 1%NaCl in drinking water. Aldosterone/salt, but not salt alone, upregulated TRAF3IP2 expression in WT mouse hearts. Further, aldosterone elevated blood pressure to a similar extent in both WT and TRAF3IP2-null groups. However, TRAF3IP2 gene deletion attenuated aldosterone/salt-induced (i) p65 and c-Jun activation, (ii) extracellular matrix (collagen Iα1 and collagen IIIα1), matrix metalloproteinase (MMP2), lysyl oxidase (LOX), inflammatory cytokine (IL-6 and IL-18), chemokine (CXCL1 and CXCL2), and adhesion molecule (ICAM1) mRNA expression in hearts, (iii) IL-6, IL-18, and MMP2 protein levels, (iv) systemic IL-6 and IL-18 levels, and (iv) cardiac hypertrophy and fibrosis. These results indicate that TRAF3IP2 is a critical signaling intermediate in aldosterone/salt-induced myocardial hypertrophy and fibrosis, and thus a potential therapeutic target in hypertensive heart disease. PMID:27040306

  5. Aldosterone Induces Renal Fibrosis and Inflammatory M1-Macrophage Subtype via Mineralocorticoid Receptor in Rats

    PubMed Central

    Martín-Fernández, Beatriz; Rubio-Navarro, Alfonso; Cortegano, Isabel; Ballesteros, Sandra; Alía, Mario; Cannata-Ortiz, Pablo; Olivares-Álvaro, Elena; Egido, Jesús; de Andrés, Belén; Gaspar, María Luisa; de las Heras, Natalia; Lahera, Vicente; Moreno, Juan Antonio

    2016-01-01

    We aimed to evaluate macrophages heterogeneity and structural, functional and inflammatory alterations in rat kidney by aldosterone + salt administration. The effects of treatment with spironolactone on above parameters were also analyzed. Male Wistar rats received aldosterone (1 mgkg-1d-1) + 1% NaCl for 3 weeks. Half of the animals were treated with spironolactone (200 mg kg-1d-1). Systolic and diastolic blood pressures were elevated (p<0.05) in aldosterone + salt–treated rats. Relative kidney weight, collagen content, fibronectin, macrophage infiltrate, CTGF, Col I, MMP2, TNF-α, CD68, Arg2, and SGK-1 were increased (p<0.05) in aldosterone + salt–treated rats, being reduced by spironolactone (p<0.05). Increased iNOS and IFN-γ mRNA gene expression (M1 macrophage markers) was observed in aldosterone + salt rats, whereas no significant differences were observed in IL-10 and gene ArgI mRNA expression or ED2 protein content (M2 macrophage markers). All the observed changes were blocked with spironolactone treatment. Macrophage depletion with liposomal clodronate reduced macrophage influx and inflammatory M1 markers (INF-γ or iNOS), whereas interstitial fibrosis was only partially reduced after this intervention, in aldosterone plus salt-treated rats. In conclusion, aldosterone + salt administration mediates inflammatory M1 macrophage phenotype and increased fibrosis throughout mineralocorticoid receptors activation. PMID:26730742

  6. Secretory function of the renin-aldosterone system in patients with anorexia nervosa.

    PubMed

    Fujita, M; Tamai, H; Mizuno, O; Nakagawa, T

    1991-01-20

    Patients with anorexia nervosa frequently demonstrate dehydration, electrolyte imbalance and low blood pressure that are secondary to starvation. Hyperactivity of the Renin-Aldosterone system and insensitivity to the pressor effects of exogenous angiotensin II are observed in Pseudo-Bartter syndrome caused by the abuse of diuretics or laxatives and self-induced vomiting, however, little information about the Renin-Aldosterone system has been reported in patients with anorexia nervosa. This study was designed to investigate the secretory function of the Renin-Aldosterone system in anorexia nervosa. The subjects were 13 patients with anorexia nervosa and 6 normal controls. Experiment 1: Angiotensin II infusion test was performed. Blood pressure was measured every 5 minutes, and the samples for plasma renin and serum aldosterone analysis were taken every 15 minutes during infusion test. Experiment 2: Plasma renin activity and serum aldosterone concentration were measured before and after one-hour walking. The results were as follows; (1) Basal plasma renin activity and serum aldosterone concentration in patients were not significantly higher than those in normal subjects. (2) Hypertensive response with elevation of the diastolic pressure during angiotensin II infusion in patients similar to that of normal subjects was observed. (3) Responses of plasma renin activity and serum aldosterone concentration after one-hour walking were significantly greater in patients than in normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2013346

  7. Polycystic ovary syndrome: Implications of measurement of plasma aldosterone, renin activity and progesterone.

    PubMed

    Armanini, Decio; Bordin, Luciana; Donà, Gabriella; Sabbadin, Chiara; Bakdounes, Leila; Ragazzi, Eugenio; Giorgino, Francesco L; Fiore, Cristina

    2012-05-01

    A positive correlation between aldosterone, inflammatory parameters, blood pressure and metabolic abnormalities in polycystic ovary syndrome (PCOS) has been reported in the early estrogenic phase. The aim of the study was to measure plasma aldosterone, plasma renin activity (PRA) and progesterone on the 21st day of the cycle, in women with PCOS and to consider the interrelationships between these hormones. Sixty-six consecutive normal BMI women with PCOS (median age 24 years, range 21-28 years) and 53 age- and body mass index-matched healthy controls were enrolled in the study. Aldosterone, aldosterone/PRA ratio (ARR) and Homeostasis Model Assessment (HOMA) index were significantly higher (p<0.0001) in PCOS women than controls. Positive correlations were found in PCOS but not in controls between (i) progesterone and aldosterone, (ii) aldosterone and PRA, (iii) PRA and progesterone. Mean blood pressures were within the normal range but significantly higher in PCOS than controls. The increase of plasma aldosterone, ARR and blood pressure in PCOS compared with controls is consistent with an increased mineralocorticoid effector mechanism in PCOS; prolonged therapy with spironolactone could counteract both the hyperandrogenism and reduce future cardiovascular risk. PMID:22387621

  8. ALDOSTERONE DYSREGULATION WITH AGING PREDICTS RENAL-VASCULAR FUNCTION AND CARDIO-VASCULAR RISK

    PubMed Central

    Brown, Jenifer M.; Underwood, Patricia C.; Ferri, Claudio; Hopkins, Paul N.; Williams, Gordon H.; Adler, Gail K.; Vaidya, Anand

    2014-01-01

    Aging and abnormal aldosterone regulation are both associated with vascular disease. We hypothesized that aldosterone dysregulation influences the age-related risk of renal- and cardio-vascular disease. We conducted an analysis of 562 subjects who underwent detailed investigations under conditions of liberal and restricted dietary sodium intake (1,124 visits) in a Clinical Research Center. Aldosterone regulation was characterized by the ratio of maximal suppression-to-stimulation (supine serum aldosterone on a liberal sodium diet divided by the same measure on a restricted sodium diet). We previously demonstrated that higher levels of this Sodium-modulated Aldosterone Suppression-Stimulation Index (SASSI) indicate greater aldosterone dysregulation. Renal plasma flow (RPF) was determined via p-aminohippurate clearance to assess basal renal hemodynamics, and the renal-vascular responses to dietary sodium manipulation and angiotensin II (AngII) infusion. Cardiovascular risk was calculated using the Framingham Risk Score. In univariate linear regression, older age (β= -4.60, p<0.0001) and higher SASSI (β= -58.63, p=0.001) predicted lower RPF and a blunted RPF response to sodium loading and AngII infusion. We observed a continuous, independent, multivariate-adjusted interaction between age and SASSI, where the inverse relationship between SASSI and RPF was most apparent with older age (p<0.05). Higher SASSI and lower RPF independently predicted higher Framingham Risk Score (p<0.0001) and together displayed an additive effect. Aldosterone regulation and age may interact to mediate renal-vascular disease. Our findings suggest that the combination of aldosterone dysregulation and renal-vascular dysfunction could additively increase the risk of future cardiovascular outcomes; therefore, aldosterone dysregulation may represent a modifiable mechanism of age-related vascular disease. PMID:24664291

  9. Aldosterone and cortisol affect the risk of sudden cardiac death in haemodialysis patients

    PubMed Central

    Drechsler, Christiane; Ritz, Eberhard; Tomaschitz, Andreas; Pilz, Stefan; Schönfeld, Stephan; Blouin, Katja; Bidlingmaier, Martin; Hammer, Fabian; Krane, Vera; März, Winfried; Allolio, Bruno; Fassnacht, Martin; Wanner, Christoph

    2013-01-01

    Background Sudden cardiac death is common and accounts largely for the excess mortality of patients on maintenance dialysis. It is unknown whether aldosterone and cortisol increase the incidence of sudden cardiac death in dialysis patients. Methods and results We analysed data from 1255 diabetic haemodialysis patients participating in the German Diabetes and Dialysis Study (4D Study). Categories of aldosterone and cortisol were determined at baseline and patients were followed for a median of 4 years. By Cox regression analyses, hazard ratios (HRs) were determined for the effect of aldosterone, cortisol, and their combination on sudden death and other adjudicated cardiovascular outcomes. The mean age of the patients was 66 ± 8 years (54% male). Median aldosterone was <15 pg/mL (detection limit) and cortisol 16.8 µg/dL. Patients with aldosterone levels >200 pg/mL had a significantly higher risk of sudden death (HR: 1.69; 95% CI: 1.06–2.69) compared with those with an aldosterone <15 pg/mL. The combined presence of high aldosterone (>200 pg/mL) and high cortisol (>21.1 µg/dL) levels increased the risk of sudden death in striking contrast to patients with low aldosterone (<15 pg/mL) and low cortisol (<13.2 µg/dL) levels (HR: 2.86, 95% CI: 1.32–6.21). Furthermore, all-cause mortality was significantly increased in the patients with high levels of both hormones (HR: 1.62, 95% CI: 1.01–2.62). Conclusions The joint presence of high aldosterone and high cortisol levels is strongly associated with sudden cardiac death as well as all-cause mortality in haemodialysed type 2 diabetic patients. Whether a blockade of the mineralocorticoid receptor decreases the risk of sudden death in these patients must be examined in future trials. PMID:23211232

  10. Interleukin-18 deficiency protects against renal interstitial fibrosis in aldosterone/salt-treated mice.

    PubMed

    Tanino, Akiko; Okura, Takafumi; Nagao, Tomoaki; Kukida, Masayoshi; Pei, Zuowei; Enomoto, Daijiro; Miyoshi, Ken-Ichi; Okamura, Haruki; Higaki, Jitsuo

    2016-10-01

    Interleukin (IL)-18 is a member of the IL-1 family of cytokines and was described originally as an interferon γ-inducing factor. Aldosterone plays a central role in the regulation of sodium and potassium homoeostasis by binding to the mineralocorticoid receptor and contributes to kidney and cardiovascular damage. Aldosterone has been reported to induce IL-18, resulting in cardiac fibrosis with induced IL-18-mediated osteopontin (OPN). We therefore hypothesized that aldosterone-induced renal fibrosis via OPN may be mediated by IL-18. To verify this hypothesis, we compared mice deficient in IL-18 and wild-type (WT) mice in a model of aldosterone/salt-induced hypertension. IL-18(-/-) and C57BL/6 WT mice were used for the uninephrectomized aldosterone/salt hypertensive model, whereas NRK-52E cells (rat kidney epithelial cells) were used in an in vitro model. In the present in vivo study, IL-18 protein expression was localized in medullary tubules in the WT mice, whereas in aldosterone-infused WT mice this expression was up-regulated markedly in the proximal tubules, especially in injured and dilated tubules. This renal damage caused by aldosterone was attenuated significantly by IL-18 knockout with down-regulation of OPN expression. In the present in vitro study, aldosterone directly induced IL-18 gene expression in renal tubular epithelial cells in a concentration- and time-dependent manner. These effects were inhibited completely by spironolactone. IL-18 may be a key mediator of aldosterone-induced renal fibrosis by inducing OPN, thereby exacerbating renal interstitial fibrosis. Inhibition of IL-18 may therefore provide a potential target for therapeutic intervention aimed at preventing the progression of renal injury. PMID:27413021

  11. Aldosterone Activates Transcription Factor Nrf2 in Kidney Cells Both In Vitro and In Vivo

    PubMed Central

    Oteiza, Patricia I.; Link, Samuel; Hey, Valentin; Stopper, Helga; Schupp, Nicole

    2014-01-01

    Abstract Aims: An increased kidney cancer risk was found in hypertensive patients, who frequently exhibit hyperaldosteronism, known to contribute to kidney injury, with oxidative stress playing an important role. The capacity of kidney cells to up-regulate transcription factor nuclear factor-erythroid-2-related factor 2 (Nrf2), a key regulator of the cellular antioxidative defense, as a prevention of aldosterone-induced oxidative damage was investigated both in vitro and in vivo. Results: Aldosterone activated Nrf2 and increased the expression of enzymes involved in glutathione (GSH) synthesis and detoxification. This activation depended on the mineralocorticoid receptor (MR) and oxidative stress. In vitro, Nrf2 activation, GSH amounts, and target gene levels decreased after 24 h, while oxidant levels remained high. Nrf2 activation could not protect cells against oxidative DNA damage, as aldosterone-induced double-strand breaks and 7,8-dihydro-8-oxo-guanine (8-oxodG) lesions steadily rose. The Nrf2 activator sulforaphane enhanced the Nrf2 response both in vitro and in vivo, thereby preventing aldosterone-induced DNA damage. In vivo, Nrf2 activation further had beneficial effects on the aldosterone-caused blood pressure increase and loss of kidney function. Innovation: This is the first study showing the activation of Nrf2 by aldosterone. Moreover, the results identify sulforaphane as a substance that is capable of preventing aldosterone-induced damage both in vivo and in vitro. Conclusion: Aldosterone-induced Nrf2 adaptive response cannot neutralize oxidative actions of chronically increased aldosterone, which, therefore could be causally involved in the increased cancer incidence of hypertensive individuals. Enhancing the cellular antioxidative defense with sulforaphane might exhibit beneficial effects. Antioxid. Redox Signal. 21, 2126–2142. PMID:24512358

  12. In Vivo Nitric Oxide Synthase Inhibitors Can Be Deprived of This Activity: Unexpected Influence of the Tetrachloroplatinate(II) Counteranion. Crystal Structures of Bis(S-Methyl-Isothiouronium)-N,N'-Bis(3-Guanidinopropyl)Piperazinium and Hexamidinium Tetrachloroplatinates(II) Salts.

    PubMed

    Morgant, G; Viossat, B; Roch-Arveiller, M; Prognon, P; Giroud, J P; Lancelot, J C; Robba, M; Huy, D N

    1998-01-01

    The synthesis and crystal structures of bis(S-methylisothiouronium) (MSTUH)(+), N,N'-bis((3- guanidinopropyl)piperazinium (PipeC3GuaH4)(4+) and hexamidinium (HexaH2)(2+) tetrachloro platinate(ll) salts ( called hereafter PtMSTU, PtPipeC3Gua and PtHexa respectively ) were investigated. These compounds contain the "amidine" function ( - C(=NH)NH(2) ) in which the H atoms supplied by the acid have become attached to the imino group of each terminal amidino function. Moreover, in PtPipeC3Gua, the nitrogen atoms of the chair-piperazine moiety are also protonated. The influence of tetrachloroplatinate(ll) counteranion ( versus sulfate, nitrate and diisethionate ) in the in vivo nitrite inhibition by the (MSTUH)(+), (PipeC3GuaH4)(4+) and (HexaH2)(2+) cations was investigated. The three tetrachloroplatinate(ll) salts, unexpectedly, do not inhibit significantly the in vivo nitrite production in comparison with the other salts (sulfate, nitrate and diisethionate and their corresponding previous countercations) which exhibit NO synthase inhibition, especially bis(S-methylisothiouronium) sulfate, a selective and potent inducible NO synthase (iNOS) inhibitor commonly used as standard. PMID:18475834

  13. Pivotal role of glycogen synthase kinase-3: A therapeutic target for Alzheimer's disease.

    PubMed

    Maqbool, Mudasir; Mobashir, Mohammad; Hoda, Nasimul

    2016-01-01

    Neurodegenerative diseases are among the most challenging diseases with poorly known mechanism of cause and paucity of complete cure. Out of all the neurodegenerative diseases, Alzheimer's disease is the most devastating and loosening of thinking and judging ability disease that occurs in the old age people. Many hypotheses came forth in order to explain its causes. In this review, we have enlightened Glycogen Synthase Kinase-3 which has been considered as a concrete cause for Alzheimer's disease. Plaques and Tangles (abnormal structures) are the basic suspects in damaging and killing of nerve cells wherein Glycogen Synthase Kinase-3 has a key role in the formation of these fatal accumulations. Various Glycogen Synthase Kinase-3 inhibitors have been reported to reduce the amount of amyloid-beta as well as the tau hyperphosphorylation in both neuronal and nonneuronal cells. Additionally, Glycogen Synthase Kinase-3 inhibitors have been reported to enhance the adult hippocampal neurogenesis in vivo as well as in vitro. Keeping the chemotype of the reported Glycogen Synthase Kinase-3 inhibitors in consideration, they may be grouped into natural inhibitors, inorganic metal ions, organo-synthetic, and peptide like inhibitors. On the basis of their mode of binding to the constituent enzyme, they may also be grouped as ATP, nonATP, and allosteric binding sites competitive inhibitors. ATP competitive inhibitors were known earlier inhibitors but they lack efficient selectivity. This led to find the new ways for the enzyme inhibition. PMID:26562543

  14. An Arabidopsis callose synthase.

    PubMed

    Ostergaard, Lars; Petersen, Morten; Mattsson, Ole; Mundy, John

    2002-08-01

    Beta-1,3-glucan polymers are major structural components of fungal cell walls, while cellulosic beta-1,4-glucan is the predominant polysaccharide in plant cell walls. Plant beta-1,3-glucan, called callose, is produced in pollen and in response to pathogen attack and wounding, but it has been unclear whether callose synthases can also produce cellulose and whether plant cellulose synthases may also produce beta-1,3-glucans. We describe here an Arabidopsis gene, AtGsl5, encoding a plasma membrane-localized protein homologous to yeast beta-1,3-glucan synthase whose expression partially complements a yeast beta-1,3-glucan synthase mutant. AtGsl5 is developmentally expressed at highest levels in flowers, consistent with flowers having high beta-1,3-glucan synthase activities for deposition of callose in pollen. A role for AtGsl5 in callose synthesis is also indicated by AtGsl5 expression in the Arabidopsis mpk4 mutant which exhibits systemic acquired resistance (SAR), elevated beta-1,3-glucan synthase activity, and increased callose levels. In addition, AtGsl5 is a likely target of salicylic acid (SA)-dependent SAR, since AtGsl5 mRNA accumulation is induced by SA in wild-type plants, while expression of the nahG salicylate hydroxylase reduces AtGsl5 mRNA levels in the mpk4 mutant. These results indicate that AtGsl5 is likely involved in callose synthesis in flowering tissues and in the mpk4 mutant. PMID:12081364

  15. Primary aldosteronism associated with severe rhabdomyolysis due to profound hypokalemia.

    PubMed

    Goto, Atsushi; Takahashi, Yoshihiko; Kishimoto, Miyako; Minowada, Shigeru; Aibe, Hitoshi; Hasuo, Kanehiro; Kajio, Hiroshi; Noda, Mitsuhiko

    2009-01-01

    A 55-year-old Japanese man was admitted to our hospital with severe weakness. Without measurement of serum electrolyte concentrations, diuretic therapy for hypertension was started 2 weeks prior to admission. Laboratory findings showed profound hypokalemia (1.4 mEq/L), and extreme elevation of the serum creatinine phosphokinase levels (15,760 IU/L), suggesting that the patient had hypokalemic paralysis and hypokalemia-induced rhabdomyolysis. Further evaluations, including adrenal venous sampling strongly suggested that he had primary aldosteronism. He was treated successfully by laparoscopic adrenalectomy. This case provides an important lesson that serum electrolyte concentrations should be measured in hypertensive patients before the administration of antihypertensive agents. PMID:19218772

  16. Genetics of Aldosterone-Producing Adenoma in Korean Patients

    PubMed Central

    Song, Young Shin; Lee, Kyu Eun; Seo, Soo Hyun; Seong, Moon-Woo; Shin, Chan Soo; Kim, Sang Wan; Kim, Seong Yeon

    2016-01-01

    Objectives Recently, somatic mutations in KCNJ5, ATP1A1, ATP2B3, and CACNA1D genes were found to be associated with the pathogenesis of aldosterone-producing adenoma (APA). This study aimed to investigate the prevalence of somatic mutations in KCNJ5, ATP1A1, ATP2B3, and CACNA1D and examine the correlations between these mutations and the clinical and biochemical characteristics in Korean patients with APA. Methods We performed targeted gene sequencing in 66 patients with APA to detect somatic mutations in these genes. Results Somatic KCNJ5 mutations were found in 47 (71.2%) of the 66 patients with APA (31 cases of p.G151R and 16 cases of p.L168R); these two mutations were mutually exclusive. Somatic mutations in the ATP1A1, ATP2B3, and CACNA1D genes were not observed. Somatic KCNJ5 mutations were more prevalent in female patients (66% versus 36.8%, respectively; P = 0.030). Moreover, patients with KCNJ5 mutations comprised a significantly higher proportion of patients younger than 35 years of age (19.1% versus 0%, respectively; P = 0.040). There were no significant differences in pre-operative blood pressure, plasma aldosterone, serum potassium, lateralization index, and adenoma size according to mutational status. Patients with KCNJ5 mutations were less likely to need antihypertensive medications after adrenalectomy compared with those without mutation (36.2% versus 63.2%; P = 0.045). Conclusions The present study demonstrated the high prevalence of somatic KCNJ5 mutations in Korean patients with APA. Carriers of somatic KCNJ5 mutations were more likely to be female. Early diagnosis and better therapeutic outcomes were associated with somatic KCNJ5 mutations in APA. PMID:26807823

  17. Geranyl diphosphate synthase from mint

    SciTech Connect

    Croteau, Rodney Bruce; Wildung, Mark Raymond; Burke, Charles Cullen; Gershenzon, Jonathan

    1999-01-01

    A cDNA encoding geranyl diphosphate synthase from peppermint has been isolated and sequenced, and the corresponding amino acid sequence has been determined. Accordingly, an isolated DNA sequence (SEQ ID No:1) is provided which codes for the expression of geranyl diphosphate synthase (SEQ ID No:2) from peppermint (Mentha piperita). In other aspects, replicable recombinant cloning vehicles are provided which code for geranyl diphosphate synthase or for a base sequence sufficiently complementary to at least a portion of the geranyl diphosphate synthase DNA or RNA to enable hybridization therewith (e.g., antisense geranyl diphosphate synthase RNA or fragments of complementary geranyl diphosphate synthase DNA which are useful as polymerase chain reaction primers or as probes for geranyl diphosphate synthase or related genes). In yet other aspects, modified host cells are provided that have been transformed, transfected, infected and/or injected with a recombinant cloning vehicle and/or DNA sequence encoding geranyl diphosphate synthase. Thus, systems and methods are provided for the recombinant expression of geranyl diphosphate synthase that may be used to facilitate the production, isolation and purification of significant quantities of recombinant geranyl diphosphate synthase for subsequent use, to obtain expression or enhanced expression of geranyl diphosphate synthase in plants in order to enhance the production of monoterpenoids, to produce geranyl diphosphate in cancerous cells as a precursor to monoterpenoids having anti-cancer properties or may be otherwise employed for the regulation or expression of geranyl diphosphate synthase or the production of geranyl diphosphate.

  18. Geranyl diphosphate synthase from mint

    SciTech Connect

    Croteau, R.B.; Wildung, M.R.; Burke, C.C.; Gershenzon, J.

    1999-03-02

    A cDNA encoding geranyl diphosphate synthase from peppermint has been isolated and sequenced, and the corresponding amino acid sequence has been determined. Accordingly, an isolated DNA sequence (SEQ ID No:1) is provided which codes for the expression of geranyl diphosphate synthase (SEQ ID No:2) from peppermint (Mentha piperita). In other aspects, replicable recombinant cloning vehicles are provided which code for geranyl diphosphate synthase or for a base sequence sufficiently complementary to at least a portion of the geranyl diphosphate synthase DNA or RNA to enable hybridization therewith (e.g., antisense geranyl diphosphate synthase RNA or fragments of complementary geranyl diphosphate synthase