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Sample records for fxr agonist gw4064

  1. FXR agonist activity of conformationally constrained analogs of GW 4064.

    Science.gov (United States)

    Akwabi-Ameyaw, Adwoa; Bass, Jonathan Y; Caldwell, Richard D; Caravella, Justin A; Chen, Lihong; Creech, Katrina L; Deaton, David N; Madauss, Kevin P; Marr, Harry B; McFadyen, Robert B; Miller, Aaron B; Navas, Frank; Parks, Derek J; Spearing, Paul K; Todd, Dan; Williams, Shawn P; Bruce Wisely, G

    2009-08-15

    Two series of conformationally constrained analogs of the FXR agonist GW 4064 1 were prepared. Replacement of the metabolically labile stilbene with either benzothiophene or naphthalene rings led to the identification of potent full agonists 2a and 2g.

  2. Conformationally constrained farnesoid X receptor (FXR) agonists: Naphthoic acid-based analogs of GW 4064.

    Science.gov (United States)

    Akwabi-Ameyaw, Adwoa; Bass, Jonathan Y; Caldwell, Richard D; Caravella, Justin A; Chen, Lihong; Creech, Katrina L; Deaton, David N; Jones, Stacey A; Kaldor, Istvan; Liu, Yaping; Madauss, Kevin P; Marr, Harry B; McFadyen, Robert B; Miller, Aaron B; Navas, Frank; Parks, Derek J; Spearing, Paul K; Todd, Dan; Williams, Shawn P; Wisely, G Bruce

    2008-08-01

    Starting from the known FXR agonist GW 4064 1a, a series of stilbene replacements were prepared. The 6-substituted 1-naphthoic acid 1b was an equipotent FXR agonist with improved developability parameters relative to 1a. Analog 1b also reduced the severity of cholestasis in the ANIT acute cholestatic rat model.

  3. Restoration of enterohepatic bile acid pathways in pregnant mice following short term activation of Fxr by GW4064

    International Nuclear Information System (INIS)

    Moscovitz, Jamie E.; Kong, Bo; Buckley, Kyle; Buckley, Brian; Guo, Grace L.; Aleksunes, Lauren M.

    2016-01-01

    The farnesoid X receptor (Fxr) controls bile acid homeostasis by coordinately regulating the expression of synthesizing enzymes (Cyp7a1, Cyp8b1), conjugating enzymes (Bal, Baat) and transporters in the ileum (Asbt, Ostα/β) and liver (Ntcp, Bsep, Ostβ). Transcriptional regulation by Fxr can be direct, or through the ileal Fgf15/FGF19 and hepatic Shp pathways. Circulating bile acids are increased during pregnancy due to hormone-mediated disruption of Fxr signaling. While this adaptation enhances lipid absorption, elevated bile acids may predispose women to develop maternal cholestasis. The objective of this study was to determine whether short-term treatment of pregnant mice with GW4064 (a potent FXR agonist) restores Fxr signaling to the level observed in virgin mice. Plasma, liver and ilea were collected from virgin and pregnant mice administered vehicle or GW4064 by oral gavage. Treatment of pregnant mice with GW4064 induced ileal Fgf15, Shp and Ostα/β mRNAs, and restored hepatic Shp, Bal, Ntcp, and Bsep back to vehicle-treated virgin levels. Pregnant mice exhibited 2.5-fold increase in Cyp7a1 mRNA compared to virgin controls, which was reduced by GW4064. Similarly treatment of mouse primary hepatocytes with plasma isolated from pregnant mice induced Cyp7a1 mRNA by nearly 3-fold as compared to virgin plasma, which could be attenuated by co-treatment with either GW4064 or recombinant FGF19 protein. Collectively, these data reveal that repressed activity of intestinal and hepatic Fxr in pregnancy, as previously demonstrated, may be restored by pharmacological activation. This study provides the basis for a novel approach to restore bile acid homeostasis in patients with maternal cholestasis. - Highlights: • Ileal bile acid pathways are altered in pregnancy in an Fxr-dependent manner. • Ileal Fxr/Fgf contributes to changes in hepatic bile acid synthesis and transport. • Treatment of pregnant mice with an Fxr agonist restores bile acid homeostasis.

  4. Restoration of enterohepatic bile acid pathways in pregnant mice following short term activation of Fxr by GW4064

    Energy Technology Data Exchange (ETDEWEB)

    Moscovitz, Jamie E.; Kong, Bo; Buckley, Kyle [Department of Pharmacology and Toxicology, Rutgers University Ernest Mario School of Pharmacy, 170 Frelinghuysen Rd., Piscataway, NJ 08854 (United States); Buckley, Brian [Environmental and Occupational Health Sciences Institute, 170 Frelinghuysen Rd., Piscataway, NJ 08854 (United States); Guo, Grace L. [Department of Pharmacology and Toxicology, Rutgers University Ernest Mario School of Pharmacy, 170 Frelinghuysen Rd., Piscataway, NJ 08854 (United States); Environmental and Occupational Health Sciences Institute, 170 Frelinghuysen Rd., Piscataway, NJ 08854 (United States); Aleksunes, Lauren M., E-mail: aleksunes@eohsi.rutgers.edu [Department of Pharmacology and Toxicology, Rutgers University Ernest Mario School of Pharmacy, 170 Frelinghuysen Rd., Piscataway, NJ 08854 (United States); Environmental and Occupational Health Sciences Institute, 170 Frelinghuysen Rd., Piscataway, NJ 08854 (United States)

    2016-11-01

    The farnesoid X receptor (Fxr) controls bile acid homeostasis by coordinately regulating the expression of synthesizing enzymes (Cyp7a1, Cyp8b1), conjugating enzymes (Bal, Baat) and transporters in the ileum (Asbt, Ostα/β) and liver (Ntcp, Bsep, Ostβ). Transcriptional regulation by Fxr can be direct, or through the ileal Fgf15/FGF19 and hepatic Shp pathways. Circulating bile acids are increased during pregnancy due to hormone-mediated disruption of Fxr signaling. While this adaptation enhances lipid absorption, elevated bile acids may predispose women to develop maternal cholestasis. The objective of this study was to determine whether short-term treatment of pregnant mice with GW4064 (a potent FXR agonist) restores Fxr signaling to the level observed in virgin mice. Plasma, liver and ilea were collected from virgin and pregnant mice administered vehicle or GW4064 by oral gavage. Treatment of pregnant mice with GW4064 induced ileal Fgf15, Shp and Ostα/β mRNAs, and restored hepatic Shp, Bal, Ntcp, and Bsep back to vehicle-treated virgin levels. Pregnant mice exhibited 2.5-fold increase in Cyp7a1 mRNA compared to virgin controls, which was reduced by GW4064. Similarly treatment of mouse primary hepatocytes with plasma isolated from pregnant mice induced Cyp7a1 mRNA by nearly 3-fold as compared to virgin plasma, which could be attenuated by co-treatment with either GW4064 or recombinant FGF19 protein. Collectively, these data reveal that repressed activity of intestinal and hepatic Fxr in pregnancy, as previously demonstrated, may be restored by pharmacological activation. This study provides the basis for a novel approach to restore bile acid homeostasis in patients with maternal cholestasis. - Highlights: • Ileal bile acid pathways are altered in pregnancy in an Fxr-dependent manner. • Ileal Fxr/Fgf contributes to changes in hepatic bile acid synthesis and transport. • Treatment of pregnant mice with an Fxr agonist restores bile acid homeostasis.

  5. Conformationally constrained farnesoid X receptor (FXR) agonists: alternative replacements of the stilbene.

    Science.gov (United States)

    Akwabi-Ameyaw, Adwoa; Caravella, Justin A; Chen, Lihong; Creech, Katrina L; Deaton, David N; Madauss, Kevin P; Marr, Harry B; Miller, Aaron B; Navas, Frank; Parks, Derek J; Spearing, Paul K; Todd, Dan; Williams, Shawn P; Wisely, G Bruce

    2011-10-15

    To further explore the optimum placement of the acid moiety in conformationally constrained analogs of GW 4064 1a, a series of stilbene replacements were prepared. The benzothiophene 1f and the indole 1g display the optimal orientation of the carboxylate for enhanced FXR agonist potency. Copyright © 2011 Elsevier Ltd. All rights reserved.

  6. Suppression of interleukin-6-induced C-reactive protein expression by FXR agonists

    International Nuclear Information System (INIS)

    Zhang Songwen; Liu Qiangyuan; Wang Juan; Harnish, Douglas C.

    2009-01-01

    C-reactive protein (CRP), a human acute-phase protein, is a risk factor for future cardiovascular events and exerts direct pro-inflammatory and pro-atherogenic properties. The farnesoid X receptor (FXR), a member of the nuclear hormone receptor superfamily, plays an essential role in the regulation of enterohepatic circulation and lipid homeostasis. In this study, we report that two synthetic FXR agonists, WAY-362450 and GW4064, suppressed interleukin-6-induced CRP expression in human Hep3B hepatoma cells. Knockdown of FXR by short interfering RNA attenuated the inhibitory effect of the FXR agonists and also increased the ability of interleukin-6 to induce CRP production. Furthermore, treatment of wild type C57BL/6 mice with the FXR agonist, WAY-362450, attenuated lipopolysaccharide-induced serum amyloid P component and serum amyloid A3 mRNA levels in the liver, whereas no effect was observed in FXR knockout mice. These data provide new evidence for direct anti-inflammatory properties of FXR.

  7. Activation of the nuclear receptor FXR improves hyperglycemia and hyperlipidemia in diabetic mice

    Science.gov (United States)

    Zhang, Yanqiao; Lee, Florence Ying; Barrera, Gabriel; Lee, Hans; Vales, Charisse; Gonzalez, Frank J.; Willson, Timothy M.; Edwards, Peter A.

    2006-01-01

    Farnesoid X receptor (FXR) plays an important role in maintaining bile acid and cholesterol homeostasis. Here we demonstrate that FXR also regulates glucose metabolism. Activation of FXR by the synthetic agonist GW4064 or hepatic overexpression of constitutively active FXR by adenovirus-mediated gene transfer significantly lowered blood glucose levels in both diabetic db/db and wild-type mice. Consistent with these data, FXR null mice exhibited glucose intolerance and insulin insensitivity. We further demonstrate that activation of FXR in db/db mice repressed hepatic gluconeogenic genes and increased hepatic glycogen synthesis and glycogen content by a mechanism that involves enhanced insulin sensitivity. In view of its central roles in coordinating regulation of both glucose and lipid metabolism, we propose that FXR agonists are promising therapeutic agents for treatment of diabetes mellitus. glucose | GW4064 | farnesoid X receptor-VP16 | triglyceride | cholesterol

  8. Conformationally constrained farnesoid X receptor (FXR) agonists: heteroaryl replacements of the naphthalene.

    Science.gov (United States)

    Bass, Jonathan Y; Caravella, Justin A; Chen, Lihong; Creech, Katrina L; Deaton, David N; Madauss, Kevin P; Marr, Harry B; McFadyen, Robert B; Miller, Aaron B; Mills, Wendy Y; Navas, Frank; Parks, Derek J; Smalley, Terrence L; Spearing, Paul K; Todd, Dan; Williams, Shawn P; Wisely, G Bruce

    2011-02-15

    To improve on the drug properties of GSK8062 1b, a series of heteroaryl bicyclic naphthalene replacements were prepared. The quinoline 1c was an equipotent FXR agonist with improved drug developability parameters relative to 1b. In addition, analog 1c lowered body weight gain and serum glucose in a DIO mouse model of diabetes. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. The FXR agonist PX20606 ameliorates portal hypertension by targeting vascular remodelling and sinusoidal dysfunction.

    Science.gov (United States)

    Schwabl, Philipp; Hambruch, Eva; Seeland, Berit A; Hayden, Hubert; Wagner, Michael; Garnys, Lukas; Strobel, Bastian; Schubert, Tim-Lukas; Riedl, Florian; Mitteregger, Dieter; Burnet, Michael; Starlinger, Patrick; Oberhuber, Georg; Deuschle, Ulrich; Rohr-Udilova, Nataliya; Podesser, Bruno K; Peck-Radosavljevic, Markus; Reiberger, Thomas; Kremoser, Claus; Trauner, Michael

    2017-04-01

    Steroidal farnesoid X receptor (FXR) agonists demonstrated potent anti-fibrotic activities and lowered portal hypertension in experimental models. The impact of the novel non-steroidal and selective FXR agonist PX20606 on portal hypertension and fibrosis was explored in this study. In experimental models of non-cirrhotic (partial portal vein ligation, PPVL, 7days) and cirrhotic (carbon tetrachloride, CCl 4 , 14weeks) portal hypertension, PX20606 (PX,10mg/kg) or the steroidal FXR agonist obeticholic acid (OCA,10mg/kg) were gavaged. We then measured portal pressure, intrahepatic vascular resistance, liver fibrosis and bacterial translocation. PX decreased portal pressure in non-cirrhotic PPVL (12.6±1.7 vs. 10.4±1.1mmHg; p=0.020) and cirrhotic CCl 4 (15.2±0.5 vs. 11.8±0.4mmHg; p=0.001) rats. In PPVL animals, we observed less bacterial translocation (-36%; p=0.041), a decrease in lipopolysaccharide binding protein (-30%; p=0.024) and splanchnic tumour necrosis factor α levels (-39%; p=0.044) after PX treatment. In CCl 4 rats, PX decreased fibrotic Sirius Red area (-43%; p=0.005), hepatic hydroxyproline (-66%; pportal pressure (-14%; p=0.041) by restoring endothelial function, 14week PX therapy additionally inhibited sinusoidal remodelling and decreased portal pressure to a greater extent (-22%; p=0.001). In human liver sinusoidal endothelial cells, PX increased eNOS and DDAH expression. The non-steroidal FXR agonist PX20606 ameliorates portal hypertension by reducing liver fibrosis, vascular remodelling and sinusoidal dysfunction. The novel drug PX20606 activates the bile acid receptor FXR and shows beneficial effects in experimental liver cirrhosis: In the liver, it reduces scarring and inflammation, and also widens blood vessels. Thus, PX20606 leads to an improved blood flow through the liver and decreases hypertension of the portal vein. Additionally, PX20606 improves the altered intestinal barrier and decreases bacterial migration from the gut. Copyright

  10. FXR agonist obeticholic acid reduces hepatic inflammation and fibrosis in a rat model of toxic cirrhosis

    Science.gov (United States)

    Verbeke, Len; Mannaerts, Inge; Schierwagen, Robert; Govaere, Olivier; Klein, Sabine; Vander Elst, Ingrid; Windmolders, Petra; Farre, Ricard; Wenes, Mathias; Mazzone, Massimiliano; Nevens, Frederik; van Grunsven, Leo A.; Trebicka, Jonel; Laleman, Wim

    2016-01-01

    Hepatic inflammation drives hepatic stellate cells (HSC), resulting in liver fibrosis. The Farnesoid-X receptor (FXR) antagonizes inflammation through NF-κB inhibition. We investigated preventive and therapeutic effects of FXR agonist obeticholic acid (OCA) on hepatic inflammation and fibrosis in toxic cirrhotic rats. Cirrhosis was induced by thioacetamide (TAA) intoxication. OCA was given during or after intoxication with vehicle-treated rats as controls. At sacrifice, fibrosis, hemodynamic and biochemical parameters were assessed. HSC activation, cell turn-over, hepatic NF-κB activation, pro-inflammatory and pro-fibrotic cytokines were determined. The effect of OCA was further evaluated in isolated HSC, Kupffer cells, hepatocytes and liver sinusoidal endothelial cells (LSEC). OCA decreased hepatic inflammation and fibrogenesis during TAA-administration and reversed fibrosis in established cirrhosis. Portal pressure decreased through reduced intrahepatic vascular resistance. This was paralleled by decreased expression of pro-fibrotic cytokines (transforming growth-factor β, connective tissue growth factor, platelet-derived growth factor β-receptor) as well as markers of hepatic cell turn-over, by blunting effects of pro-inflammatory cytokines (e.g. monocyte chemo-attractant protein-1). In vitro, OCA inhibited both LSEC and Kupffer cell activation; while HSC remained unaffected. This related to NF-κB inhibition via up-regulated IκBα. In conclusion, OCA inhibits hepatic inflammation in toxic cirrhotic rats resulting in decreased HSC activation and fibrosis. PMID:27634375

  11. A dual agonist of farnesoid X receptor (FXR) and the G protein-coupled receptor TGR5, INT-767, reverses age-related kidney disease in mice.

    Science.gov (United States)

    Wang, Xiaoxin X; Luo, Yuhuan; Wang, Dong; Adorini, Luciano; Pruzanski, Mark; Dobrinskikh, Evgenia; Levi, Moshe

    2017-07-21

    Even in healthy individuals, renal function gradually declines during aging. However, an observed variation in the rate of this decline has raised the possibility of slowing or delaying age-related kidney disease. One of the most successful interventional measures that slows down and delays age-related kidney disease is caloric restriction. We undertook the present studies to search for potential factors that are regulated by caloric restriction and act as caloric restriction mimetics. Based on our prior studies with the bile acid-activated nuclear hormone receptor farnesoid X receptor (FXR) and G protein-coupled membrane receptor TGR5 that demonstrated beneficial effects of FXR and TGR5 activation in the kidney, we reasoned that FXR and TGR5 could be excellent candidates. We therefore determined the effects of aging and caloric restriction on the expression of FXR and TGR5 in the kidney. We found that FXR and TGR5 expression levels are decreased in the aging kidney and that caloric restriction prevents these age-related decreases. Interestingly, in long-lived Ames dwarf mice, renal FXR and TGR5 expression levels were also increased. A 2-month treatment of 22-month-old C57BL/6J mice with the FXR-TGR5 dual agonist INT-767 induced caloric restriction-like effects and reversed age-related increases in proteinuria, podocyte injury, fibronectin accumulation, TGF-β expression, and, most notably, age-related impairments in mitochondrial biogenesis and mitochondrial function. Furthermore, in podocytes cultured in serum obtained from old mice, INT-767 prevented the increases in the proinflammatory markers TNF-α, toll-like receptor 2 (TLR2), and TLR4. In summary, our results indicate that FXR and TGR5 may play an important role in modulation of age-related kidney disease. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Gene expression profiling in human precision cut liver slices in response to the FXR agonist obeticholic acid.

    Science.gov (United States)

    Ijssennagger, Noortje; Janssen, Aafke W F; Milona, Alexandra; Ramos Pittol, José M; Hollman, Danielle A A; Mokry, Michal; Betzel, Bark; Berends, Frits J; Janssen, Ignace M; van Mil, Saskia W C; Kersten, Sander

    2016-05-01

    The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH) and type 2 diabetes, activates FXR. Mouse studies demonstrated that FXR activation by OCA alters hepatic expression of many genes. However, no data are available on the effects of OCA in the human liver. Here we generated gene expression profiles in human precision cut liver slices (hPCLS) after treatment with OCA. hPCLS were incubated with OCA for 24 h. Wild-type or FXR(-/-) mice received OCA or vehicle by oral gavage for 7 days. Transcriptomic analysis showed that well-known FXR target genes, including NR0B2 (SHP), ABCB11 (BSEP), SLC51A (OSTα) and SLC51B (OSTβ), and ABCB4 (MDR3) are regulated by OCA in hPCLS. Ingenuity pathway analysis confirmed that 'FXR/RXR activation' is the most significantly changed pathway upon OCA treatment. Comparison of gene expression profiles in hPCLS and mouse livers identified 18 common potential FXR targets. ChIP-sequencing in mouse liver confirmed FXR binding to IR1 sequences of Akap13, Cgnl1, Dyrk3, Pdia5, Ppp1r3b and Tbx6. Our study shows that hPCLS respond to OCA treatment by upregulating well-known FXR target genes, demonstrating its suitability to study FXR-mediated gene regulation. We identified six novel bona-fide FXR target genes in both mouse and human liver. Finally, we discuss a possible explanation for changes in high or low density lipoprotein observed in NASH and primary biliary cholangitis patients treated with OCA based on the genomic expression profile in hPCLS. Copyright © 2016 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.

  13. Gene expression profiling in human precision cut liver slices in response to the FXR agonist obeticholic acid

    NARCIS (Netherlands)

    IJssennagger, Noortje; Janssen, A.W.F.; Milona, Alexandra; Ramos Pittol, J.M.; Hollman, D.A.A.; Mokry, Michal; Betzel, Bark; Berends, F.J.; Janssen, I.M.; Mil, van S.W.C.; Kersten, Sander

    2016-01-01

    Background & Aims: The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH) and type 2 diabetes, activates FXR. Mouse

  14. Gene expression profiling in human precision cut liver slices in response to the FXR agonist obeticholic acid

    NARCIS (Netherlands)

    Ijssennagger, Noortje; Janssen, Aafke W F; Milona, Alexandra; Ramos Pittol, José M; Hollman, Danielle A A; Mokry, Michal; Betzel, Bark; Berends, Frits J; Janssen, Ignace M; van Mil, Saskia W C; Kersten, Sander

    2016-01-01

    BACKGROUND & AIMS: The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH) and type 2 diabetes, activates FXR. Mouse studies

  15. Gene expression profiling in human precision-cut liver slices upon treatment with the FXR agonist obeticholic acid [human

    NARCIS (Netherlands)

    IJssennagger, Noortje; Janssen, Aafke; Mil, van Saskia; Kersten, Sander

    2016-01-01

    Background: The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA; also known as INT-747 or 6α-ethyl-chenodeoxycholic acid), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH)

  16. Gene expression profiling in human precision-cut liver slices upon treatment with the FXR agonist obeticholic acid [mouse

    NARCIS (Netherlands)

    IJssennagger, Noortje; Janssen, Aafke; Kersten, Sander; Mil, van S.W.C.

    2016-01-01

    Background: The bile acid-activated farnesoid X receptor (FXR) is a nuclear receptor regulating bile acid, glucose and cholesterol homeostasis. Obeticholic acid (OCA; also known as INT-747 or 6α-ethyl-chenodeoxycholic acid), a promising drug for the treatment of non-alcoholic steatohepatitis (NASH)

  17. Cardiopulmonary protective effects of the selective FXR agonist obeticholic acid in the rat model of monocrotaline-induced pulmonary hypertension.

    Science.gov (United States)

    Vignozzi, Linda; Morelli, Annamaria; Cellai, Ilaria; Filippi, Sandra; Comeglio, Paolo; Sarchielli, Erica; Maneschi, Elena; Vannelli, Gabriella Barbara; Adorini, Luciano; Maggi, Mario

    2017-01-01

    Farnesoid X receptor (FXR) activation by obeticholic acid (OCA) has been demonstrated to inhibit inflammation and fibrosis development and even induce fibrosis regression in liver, kidney and intestine in multiple disease models. OCA also inhibits liver fibrosis in nonalcoholic steatohepatitis patients. FXR activation has also been demonstrated to suppress the inflammatory response and to promote lung repair after lung injury. This study investigated the effects of OCA treatment (3, 10 or 30mg/kg, daily for 5days a week, for 7 and/or 28 days) on inflammation, tissue remodeling and fibrosis in the monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH) rat model. Treatment with OCA attenuated MCT-induced increased pulmonary arterial wall thickness and right ventricular hypertrophy, by i) blunting pathogenic inflammatory mechanisms (downregulation of interleukin 6, IL-6, and monocyte chemoattractant protein-1, MCP-1) and ii) enhancing protective mechanisms counteracting fibrosis and endothelial/mesenchymal transition. MCT-injected rats also showed a marked decrease of pulmonary artery responsiveness to both endothelium-dependent and independent relaxant stimuli, such as acetylcholine and a nitric oxide donor, sodium nitroprusside. Administration of OCA (30mg/kg) normalized this decreased responsiveness. Accordingly, OCA treatment induced profound beneficial effects on lung histology. In particular, both OCA doses markedly reduced the MCT-induced medial wall thickness increase in small pulmonary arteries. To evaluate the objective functional improvement by OCA treatment of MCT-induced PAH, we performed a treadmill test and measured duration of exercise. MCT significantly reduced, and OCA normalized treadmill endurance. Results with OCA were similar, or even superior, to those obtained with tadalafil, a well-established treatment of PAH. In conclusion, OCA treatment demonstrates cardiopulmonary protective effects, modulating lung vascular remodeling, reducing

  18. Farnesoid X receptor (FXR activation and FXR genetic variation in inflammatory bowel disease.

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    Rian M Nijmeijer

    Full Text Available BACKGROUND: We previously showed that activation of the bile salt nuclear receptor Farnesoid X Receptor (FXR protects against intestinal inflammation in mice. Reciprocally, these inflammatory mediators may decrease FXR activation. We investigated whether FXR activation is repressed in the ileum and colon of inflammatory bowel disease (IBD patients in remission. Additionally, we evaluated whether genetic variation in FXR is associated with IBD. METHODS: mRNA expression of FXR and FXR target gene SHP was determined in ileal and colonic biopsies of patients with Crohn's colitis (n = 15 and ulcerative colitis (UC; n = 12, all in clinical remission, and healthy controls (n = 17. Seven common tagging SNPs and two functional SNPs in FXR were genotyped in 2355 Dutch IBD patients (1162 Crohn's disease (CD and 1193 UC and in 853 healthy controls. RESULTS: mRNA expression of SHP in the ileum is reduced in patients with Crohn's colitis but not in patients with UC compared to controls. mRNA expression of villus marker Villin was correlated with FXR and SHP in healthy controls, a correlation that was weaker in UC patients and absent in CD patients. None of the SNPs was associated with IBD, UC or CD, nor with clinical subgroups of CD. CONCLUSIONS: FXR activation in the ileum is decreased in patients with Crohn's colitis. This may be secondary to altered enterohepatic circulation of bile salts or transrepression by inflammatory signals but does not seem to be caused by the studied SNPs in FXR. Increasing FXR activity by synthetic FXR agonists may have benefit in CD patients.

  19. Genome-wide binding and transcriptome analysis of human farnesoid X receptor in primary human hepatocytes.

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    Le Zhan

    Full Text Available Farnesoid X receptor (FXR, NR1H4 is a ligand-activated transcription factor, belonging to the nuclear receptor superfamily. FXR is highly expressed in the liver and is essential in regulating bile acid homeostasis. FXR deficiency is implicated in numerous liver diseases and mice with modulation of FXR have been used as animal models to study liver physiology and pathology. We have reported genome-wide binding of FXR in mice by chromatin immunoprecipitation - deep sequencing (ChIP-seq, with results indicating that FXR may be involved in regulating diverse pathways in liver. However, limited information exists for the functions of human FXR and the suitability of using murine models to study human FXR functions.In the current study, we performed ChIP-seq in primary human hepatocytes (PHHs treated with a synthetic FXR agonist, GW4064 or DMSO control. In parallel, RNA deep sequencing (RNA-seq and RNA microarray were performed for GW4064 or control treated PHHs and wild type mouse livers, respectively.ChIP-seq showed similar profiles of genome-wide FXR binding in humans and mice in terms of motif analysis and pathway prediction. However, RNA-seq and microarray showed more different transcriptome profiles between PHHs and mouse livers upon GW4064 treatment.In summary, we have established genome-wide human FXR binding and transcriptome profiles. These results will aid in determining the human FXR functions, as well as judging to what level the mouse models could be used to study human FXR functions.

  20. Binding free energy predictions of farnesoid X receptor (FXR) agonists using a linear interaction energy (LIE) approach with reliability estimation: application to the D3R Grand Challenge 2

    Science.gov (United States)

    Rifai, Eko Aditya; van Dijk, Marc; Vermeulen, Nico P. E.; Geerke, Daan P.

    2018-01-01

    Computational protein binding affinity prediction can play an important role in drug research but performing efficient and accurate binding free energy calculations is still challenging. In the context of phase 2 of the Drug Design Data Resource (D3R) Grand Challenge 2 we used our automated eTOX ALLIES approach to apply the (iterative) linear interaction energy (LIE) method and we evaluated its performance in predicting binding affinities for farnesoid X receptor (FXR) agonists. Efficiency was obtained by our pre-calibrated LIE models and molecular dynamics (MD) simulations at the nanosecond scale, while predictive accuracy was obtained for a small subset of compounds. Using our recently introduced reliability estimation metrics, we could classify predictions with higher confidence by featuring an applicability domain (AD) analysis in combination with protein-ligand interaction profiling. The outcomes of and agreement between our AD and interaction-profile analyses to distinguish and rationalize the performance of our predictions highlighted the relevance of sufficiently exploring protein-ligand interactions during training and it demonstrated the possibility to quantitatively and efficiently evaluate if this is achieved by using simulation data only.

  1. Reversal of metabolic disorders by pharmacological activation of bile acid receptors TGR5 and FXR

    Directory of Open Access Journals (Sweden)

    Kavita Jadhav

    2018-03-01

    Full Text Available Objectives: Activation of the bile acid (BA receptors farnesoid X receptor (FXR or G protein-coupled bile acid receptor (GPBAR1; TGR5 improves metabolic homeostasis. In this study, we aim to determine the impact of pharmacological activation of bile acid receptors by INT-767 on reversal of diet-induced metabolic disorders, and the relative contribution of FXR vs. TGR5 to INT-767's effects on metabolic parameters. Methods: Wild-type (WT, Tgr5−/−, Fxr−/−, Apoe−/− and Shp−/− mice were used to investigate whether and how BA receptor activation by INT-767, a semisynthetic agonist for both FXR and TGR5, could reverse diet-induced metabolic disorders. Results: INT-767 reversed HFD-induced obesity dependent on activation of both TGR5 and FXR and also reversed the development of atherosclerosis and non-alcoholic fatty liver disease (NAFLD. Mechanistically, INT-767 improved hypercholesterolemia by activation of FXR and induced thermogenic genes via activation of TGR5 and/or FXR. Furthermore, INT-767 inhibited several lipogenic genes and de novo lipogenesis in the liver via activation of FXR. We identified peroxisome proliferation-activated receptor γ (PPARγ and CCAAT/enhancer-binding protein α (CEBPα as novel FXR-regulated genes. FXR inhibited PPARγ expression by inducing small heterodimer partner (SHP whereas the inhibition of CEBPα by FXR was SHP-independent. Conclusions: BA receptor activation can reverse obesity, NAFLD, and atherosclerosis by specific activation of FXR or TGR5. Our data suggest that, compared to activation of FXR or TGR5 only, dual activation of both FXR and TGR5 is a more attractive strategy for treatment of common metabolic disorders. Keywords: Farnesoid X receptor, TGR5, Atherosclerosis, Obesity, NAFLD

  2. Discovery that theonellasterol a marine sponge sterol is a highly selective FXR antagonist that protects against liver injury in cholestasis.

    Directory of Open Access Journals (Sweden)

    Barbara Renga

    Full Text Available BACKGROUND: The farnesoid-x-receptor (FXR is a bile acid sensor expressed in the liver and gastrointestinal tract. Despite FXR ligands are under investigation for treatment of cholestasis, a biochemical condition occurring in a number of liver diseases for which available therapies are poorly effective, mice harboring a disrupted FXR are protected against liver injury caused by bile acid overload in rodent models of cholestasis. Theonellasterol is a 4-methylene-24-ethylsteroid isolated from the marine sponge Theonella swinhoei. Here, we have characterized the activity of this theonellasterol on FXR-regulated genes and biological functions. PRINCIPAL FINDINGS: Interrogation of HepG2 cells, a human hepatocyte cell line, by microarray analysis and transactivation assay shows that theonellasterol is a selective FXR antagonist, devoid of any agonistic or antagonistic activity on a number of human nuclear receptors including the vitamin D receptor, PPARs, PXR, LXRs, progesterone, estrogen, glucorticoid and thyroid receptors, among others. Exposure of HepG2 cells to theonellasterol antagonizes the effect of natural and synthetic FXR agonists on FXR-regulated genes, including SHP, OSTα, BSEP and MRP4. A proof-of-concept study carried out to investigate whether FXR antagonism rescues mice from liver injury caused by the ligation of the common bile duct, a model of obstructive cholestasis, demonstrated that theonellasterol attenuates injury caused by bile duct ligation as measured by assessing serum alanine aminostrasferase levels and extent of liver necrosis at histopathology. Analysis of genes involved in bile acid uptake and excretion by hepatocytes revealed that theonellasterol increases the liver expression of MRP4, a basolateral transporter that is negatively regulated by FXR. Administering bile duct ligated mice with an FXR agonist failed to rescue from liver injury and downregulated the expression of MRP4. CONCLUSIONS: FXR antagonism in vivo

  3. Initial performance parameters on FXR

    International Nuclear Information System (INIS)

    Kulke, B.; Innes, T.G.; Kihara, R.; Scarpetti, R.D.

    1982-01-01

    Construction of the new flash x-ray induction LINAC (FXR) at Lawrence Livermore National Laboratory has been completed. Initial tuning of the machine has produced stable current pulses in excess of 2 kA at the design energy of 20 MeV, with an 80 ns FWHM pulse width, producing single-pulse radiation doses near 500 Roentgen at one meter from the target. The electronic spot size on the bremsstrahlung target is estimated at 3 to 5 mm. In this paper we will discuss the basic FXR design; running-in and tuning of the machine; emittance measurements; beam stability; switch gap synchronization; and measurements of the radiation dose and angular distribution

  4. Regulation of DDAH1 as a Potential Therapeutic Target for Treating Cardiovascular Diseases

    Directory of Open Access Journals (Sweden)

    Xiaoyu Liu

    2013-01-01

    Full Text Available Asymmetric dimethylarginine (ADMA is an endogenous nitric oxide synthase inhibitor that blocks nitric oxide production, while congestive heart failure is associated with increased plasma and tissue ADMA content. Increased plasma ADMA is a strong and independent predictor of all-cause mortality in the community and the strongest predictor of mortality in patients after myocardial infarction. Recent studies demonstrated that dimethylarginine dimethylaminohydrolase-1 (DDAH1 is the critical enzyme for ADMA degradation and thereby plays an important role in maintaining cardiovascular nitric oxide bioavailability. Interestingly, activation of the farnesoid X receptor (FXR through the bile acid ursodeoxycholic acid (UDCA or synthetic FXR agonists, such as GW4064, can increase DDAH1 expression. Thus, modulating DDAH1 activity through FXR receptor agonists such as UDCA could be a therapeutic target for treating reduced nitric oxide bioavailability in congestive heart failure and other cardiovascular diseases.

  5. Statins and transcriptional regulation: The FXR connection

    International Nuclear Information System (INIS)

    Habeos, Ioannis; Ziros, Panos G.; Psyrogiannis, Agathoklis; Vagenakis, Apostolos G.; Papavassiliou, Athanasios G.

    2005-01-01

    Farnesoid X receptor (FXR) is a nuclear receptor involved in lipoprotein as well as glucose metabolism. Statins are widely used hypolipidemic agents with many pleiotropic actions. It is known that statins affect other nuclear hormone receptors, but no reports are available on the effect of these drugs on FXR. Employing an animal model (Syrian hamsters), we hereby present evidence to demonstrate that Simvastatin, a broadly prescribed statin, decreases the expression of FXR at both the RNA and protein levels and down-regulates its DNA-binding activity. This novel property may have important implications on the mode statins influence on lipoprotein and carbohydrate homeostasis in the organism

  6. Reconstruction of FXR Beam Conditions

    International Nuclear Information System (INIS)

    Nexen, W E; Scarpetti, R D; Zentler, J

    2001-01-01

    Beam-envelope radius, envelope angle, and beam emittance can be derived from measurements of beam radius for at least three different transport conditions. We have used this technique to reconstruct exit parameters from the FXR injector and accelerator. We use a diamagnetic loop (DML) to measure the magnetic moment of the high current beam. With no assumptions about radial profile, we can derive the beam mean squire radius from the moment under certain easily met conditions. Since it is this parameter which is required for the reconstruction, it is evident that the DML is the ideal diagnostic for this technique. The simplest application of this technique requires at least three shots for a reconstruction but in reality requires averaging over many more shots because of shot to shot variation. Since DML measurements do not interfere with the beam, single shot time resolved measurements of the beam parameters appear feasible if one uses an array of at least three DMLs separated by known transport conditions

  7. FXR-deficiency confers increased susceptibility to torpor

    NARCIS (Netherlands)

    Cariou, Bertrand; Bouchaert, Emmanuel; Abdelkarim, Mouaadh; Dumont, Julie; Caron, Sandrine; Fruchart, Jean-Charles; Burcelin, Remy; Kuipers, Folkert; Staels, Bart

    2007-01-01

    The role of the nuclear receptor FXR in adaptive thermogenesis was investigated using FXR-deficient mice. Despite elevated serum bile acid concentrations and increased mRNA expression profiles of thermogenic genes in brown adipose tissue, FXR-deficiency did not alter energy expenditure under basal

  8. An Intestinal Farnesoid X Receptor–Ceramide Signaling Axis Modulates Hepatic Gluconeogenesis in Mice

    Science.gov (United States)

    Xie, Cen; Shi, Jingmin; Gao, Xiaoxia; Sun, Dongxue; Sun, Lulu; Wang, Ting; Takahashi, Shogo; Anitha, Mallappa; Krausz, Kristopher W.; Patterson, Andrew D.

    2017-01-01

    Increasing evidence supports the view that intestinal farnesoid X receptor (FXR) is involved in glucose tolerance and that FXR signaling can be profoundly impacted by the gut microbiota. Selective manipulation of the gut microbiota–FXR signaling axis was reported to significantly impact glucose intolerance, but the precise molecular mechanism remains largely unknown. Here, caffeic acid phenethyl ester (CAPE), an over-the-counter dietary supplement and an inhibitor of bacterial bile salt hydrolase, increased levels of intestinal tauro-β-muricholic acid, which selectively suppresses intestinal FXR signaling. Intestinal FXR inhibition decreased ceramide levels by suppressing expression of genes involved in ceramide synthesis specifically in the intestinal ileum epithelial cells. The lower serum ceramides mediated decreased hepatic mitochondrial acetyl-CoA levels and pyruvate carboxylase (PC) activities and attenuated hepatic gluconeogenesis, independent of body weight change and hepatic insulin signaling in vivo; this was reversed by treatment of mice with ceramides or the FXR agonist GW4064. Ceramides substantially attenuated mitochondrial citrate synthase activities primarily through the induction of endoplasmic reticulum stress, which triggers increased hepatic mitochondrial acetyl-CoA levels and PC activities. These results reveal a mechanism by which the dietary supplement CAPE and intestinal FXR regulates hepatic gluconeogenesis and suggest that inhibiting intestinal FXR is a strategy for treating hyperglycemia. PMID:28223344

  9. Transient impairment of the adaptive response to fasting in FXR-deficient mice

    NARCIS (Netherlands)

    Cariou, B; van Harmelen, K; Duran-Sandoval, D; van Dijk, T; Grefhorst, A; Bouchaert, E; Fruchart, JC; Gonzalez, FJ; Kuipers, F; Staels, B

    2005-01-01

    The farnesoid X receptor (FXR) has been suggested to play a role in gluconeogenesis. To determine whether FXR modulates the response to fasting in vivo, FXR-deficient (FXR-/-) and wild-type mice were submitted to fasting for 48 h. Our results demonstrate that FXR modulates the kinetics of

  10. Activation of farnesoid X receptor increases the expression of cytokine inducible SH2-containing protein in HepG2 cells.

    Science.gov (United States)

    Xu, Zhizhen; Huang, Gang; Gong, Wei; Zhao, Yuanyin; Zhou, Peng; Zeng, Yijun; He, Fengtian

    2012-11-01

    Cytokine inducible SH2-containing protein (CISH), which negatively regulates cytokine signaling by inhibiting JAK2/STAT5 activity, is regarded as a therapeutic target for inflammatory diseases. Farnesoid X receptor (FXR), a ligand-activated transcription factor, has been proposed to play a protective function in the inflammatory responses. However, the role of FXR in modulation of CISH expression is unknown. In the present study, we for the first time identified that in human hepatoma cell line HepG2 the activation of FXR by the natural agonist chenodeoxycholic acid (CDCA) and the synthetic specific agonist GW4064 upregulated CISH at both transcriptional and translational levels, and inhibited interleukin (IL)6-induced STAT5 activation. Moreover, the in vivo experiment demonstrated that gavaging mice with CDCA increased CISH expression and reduced basal STAT5 phosphorylation in liver tissues. Reporter assay showed that FXR agonists enhanced the transcriptional activity of CISH promoter. These data suggest that FXR may serve as a novel molecular target for manipulating CISH expression in hepatocytes. FXR-mediated upregulation of CISH may play an important role in the homeostasis of cytokine signal networks and be beneficial to control cytokine-associated inflammatory diseases.

  11. Differential modulation of FXR activity by chlorophacinone and ivermectin analogs

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Chia-Wen [NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD (United States); Hsieh, Jui-Hua [National Toxicology Program, National Institutes of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC (United States); Huang, Ruili [NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD (United States); Pijnenburg, Dirk [PamGene International B.V., Wolvenhoek 10, 5211 HH ' s-Hertogenbosch (Netherlands); Khuc, Thai [NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD (United States); Hamm, Jon [Integrated Laboratory System, Inc., Morrisville, NC (United States); Zhao, Jinghua; Lynch, Caitlin [NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD (United States); Beuningen, Rinie van [PamGene International B.V., Wolvenhoek 10, 5211 HH ' s-Hertogenbosch (Netherlands); Chang, Xiaoqing [Integrated Laboratory System, Inc., Morrisville, NC (United States); Houtman, René [PamGene International B.V., Wolvenhoek 10, 5211 HH ' s-Hertogenbosch (Netherlands); Xia, Menghang, E-mail: mxia@mail.nih.gov [NIH Chemical Genomics Center, National Center for Advancing Translational Sciences, National Institutes of Health, Bethesda, MD (United States)

    2016-12-15

    Chemicals that alter normal function of farnesoid X receptor (FXR) have been shown to affect the homeostasis of bile acids, glucose, and lipids. Several structural classes of environmental chemicals and drugs that modulated FXR transactivation were previously identified by quantitative high-throughput screening (qHTS) of the Tox21 10 K chemical collection. In the present study, we validated the FXR antagonist activity of selected structural classes, including avermectin anthelmintics, dihydropyridine calcium channel blockers, 1,3-indandione rodenticides, and pyrethroid pesticides, using in vitro assay and quantitative structural-activity relationship (QSAR) analysis approaches. (Z)-Guggulsterone, chlorophacinone, ivermectin, and their analogs were profiled for their ability to alter CDCA-mediated FXR binding using a panel of 154 coregulator motifs and to induce or inhibit transactivation and coactivator recruitment activities of constitutive androstane receptor (CAR), liver X receptor alpha (LXRα), or pregnane X receptor (PXR). Our results showed that chlorophacinone and ivermectin had distinct modes of action (MOA) in modulating FXR-coregulator interactions and compound selectivity against the four aforementioned functionally-relevant nuclear receptors. These findings collectively provide mechanistic insights regarding compound activities against FXR and possible explanations for in vivo toxicological observations of chlorophacinone, ivermectin, and their analogs. - Highlights: • A subset of Tox21 chemicals was investigated for FXR antagonism. • In vitro and computational approaches were used to evaluate FXR antagonists. • Chlorophacinone and ivermectin had distinct patterns in modulating FXR activity.

  12. Farnesoid X receptor up-regulates expression of Lipid transfer inhibitor protein in liver cells and mice

    Energy Technology Data Exchange (ETDEWEB)

    Li, Liangpeng [Department of Biochemistry and Molecular Biology, College of Basic Medical Science, Third Military Medical University, Chongqing 400038 (China); Liu, Hong [Department of Hematology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037 (China); Peng, Jiahe; Wang, Yongchao; Zhang, Yan; Dong, Jinyu; Liu, Xiaohua; Guo, Dongmei [Department of Biochemistry and Molecular Biology, College of Basic Medical Science, Third Military Medical University, Chongqing 400038 (China); Jiang, Yu, E-mail: yujiang61@gmail.com [Department of Biochemistry and Molecular Biology, College of Basic Medical Science, Third Military Medical University, Chongqing 400038 (China)

    2013-11-29

    Highlights: •FXR up-regulates apoF. •It binds to ER1 element. •It activates apoF gene promoter. -- Abstract: Apolipoprotein F is a component protein mainly secreted by liver and resides on several lipoprotein classes. It can inhibit lipids transfer between different lipoproteins. FXR is a member of the nuclear receptor superfamily which is also highly expressed in the liver. It modulates bile acids synthesis and lipids metabolism by transcriptional regulation. We aimed to determine whether apoF can be regulated by FXR. The FXR agonist Chenodeoxycholic acid (CDCA) and GW4064 both can activate the expression of apoF in liver cell lines and in C57/BL6 mouse liver. This is dependent on the binding of FXR to the FXR element ER1 (−2904 to −2892 bp) in the apoF gene promoter. Taken together, we have identified apoF as likely another target gene of FXR.

  13. On the Pharmacology of Farnesoid X Receptor Agonists: Give me an “A”, Like in “Acid”

    Directory of Open Access Journals (Sweden)

    Eva Hambruch

    2016-06-01

    Full Text Available The Farnesoid X Receptor (FXR has recently moved into the spotlight through the release of clinical data using Obeticholic Acid, an FXR agonist, that demonstrated effectiveness of this bile acid-like drug in patients with Primary Biliary Cirrhosis and Non-alcoholic Steatohepatitis (NASH. FXR holds the promise to become an attractive drug target for various conditions, from Non-alcoholic Fatty Liver Disease (NAFLD, NASH, liver cirrhosis, portal hypertension and a variety of cholestatic disorders to intestinal diseases including inflammatory bowel disease and bile acid diarrhea. Despite the wide therapeutic potential, surprisingly little is known about the pharmacology, pharmacokinetics and tissue distribution properties of drugs targeting FXR. Are tissue specific FXR agonists preferable for different indications, or might one type of ligand fit all purposes? This review aims to summarize the sparse data which are available on this clinically and pharmacologically relevant topic and provides a mechanistic model for understanding tissue-specific effects in vivo.

  14. The bile acid sensor FXR protects against dyslipidemia and aortic plaques development induced by the HIV protease inhibitor ritonavir in mice.

    Directory of Open Access Journals (Sweden)

    Andrea Mencarelli

    Full Text Available BACKGROUND: Although human immunodeficiency virus (HIV-related morbidity and mortality rates in patients treated with a combination of high active antiretroviral therapy (HAART have declined, significant metabolic/vascular adverse effects associated with the long term use of HIV protease inhibitors (PIs have emerged as a significant side effect. Here we illustrate that targeting the bile acid sensor farnesoid X receptor (FXR protects against dyslipidemia and vascular injury induced HIV-PIs in rodents. METHODOLOGY/PRINCIPAL FINDINGS: Administration of the HIV PI ritonavir to wild type mice increased plasma triacylglycerols and cholesterol levels and this effect was exacerbated by dosing ritonavir to mice harbouring a disrupted FXR. Dyslipidemia induced by ritonavir associated with a shift in the liver expression of signature genes, Sterol Regulatory Element-Binding Protein (SREBP-1 and fatty acid synthase. Treating wild type mice with the FXR agonist (chenodeoxycholic acid, CDCA protected against development of dyslipidemia induced by ritonavir. Administration of ritonavir to ApoE(-/- mice, a strain that develop spontaneously atherosclerosis, increased the extent of aortic plaques without worsening the dyslipidemia. Treating these mice with CDCA reduced the extent of aortic plaques by 70% without changing plasma lipoproteins or the liver expression of signature genes. A beneficial effect on aortic plaques was also obtained by treating ApoE(-/- mice with gemfibrozil, a PPARα agonist. FXR activation counter-regulated induction of expression/activity of CD36 caused by HIV-PIs in circulating monocytes and aortic plaques. In macrophages cell lines, CDCA attenuated CD36 induction and uptake of acetylated LDL caused by ritonavir. Natural and synthetic FXR ligands reduced the nuclear translocation of SREBP1c caused by ritonavir. CONCLUSIONS/SIGNIFICANCE: Activation of the bile acid sensor FXR protects against dyslipidemia and atherosclerotic caused by

  15. DAX1 suppresses FXR transactivity as a novel co-repressor

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jin; Lu, Yan; Liu, Ruya; Xiong, Xuelian; Zhang, Zhijian; Zhang, Xianfeng [Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025 (China); Ning, Guang, E-mail: guangning@gmail.com.cn [Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025 (China); The Key Laboratory of Endocrine Tumors and The Division of Endocrine and Metabolic Diseases, E-Institute of Shanghai Universities, Shanghai 200025 (China); Li, Xiaoying, E-mail: lixy@sibs.ac.cn [Shanghai Clinical Center for Endocrine and Metabolic Diseases, Shanghai Institute of Endocrine and Metabolic Diseases, Department of Endocrinology and Metabolism, Rui-Jin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025 (China); The Key Laboratory of Endocrine Tumors and The Division of Endocrine and Metabolic Diseases, E-Institute of Shanghai Universities, Shanghai 200025 (China)

    2011-09-09

    Highlights: {yields} DAX1 is co-localized with FXR and interacts with FXR. {yields} DAX1 acts as a negative regulator of FXR. {yields} Three LXXLL motifs in the N-terminus of DAX1 were required. {yields} DAX1 suppresses FXR transactivation by competing with co-activators. -- Abstract: Bile acid receptor FXR (farnesoid X receptor) is a key regulator of hepatic bile acid, glucose and lipid homeostasis through regulation of numerous genes involved in the process of bile acid, triglyceride and glucose metabolism. DAX1 (dosage-sensitive sex reversal adrenal hypoplasia congenital critical region on X chromosome, gene 1) is an atypical member of the nuclear receptor family due to lack of classical DNA-binding domains and acts primarily as a co-repressor of many nuclear receptors. Here, we demonstrated that DAX1 is co-localized with FXR in the nucleus and acted as a negative regulator of FXR through a physical interaction with FXR. Our study showed that over-expression of DAX1 down-regulated the expression of FXR target genes, whereas knockdown of DAX1 led to their up-regulation. Furthermore, three LXXLL motifs in the N-terminus of DAX1 were required for the full repression of FXR transactivation. In addition, our study characterized that DAX1 suppresses FXR transactivation via competing with co-activators such as SRC-1 and PGC-1{alpha}. In conclusion, DAX1 acts as a co-repressor to negatively modulate FXR transactivity.

  16. DAX1 suppresses FXR transactivity as a novel co-repressor

    International Nuclear Information System (INIS)

    Li, Jin; Lu, Yan; Liu, Ruya; Xiong, Xuelian; Zhang, Zhijian; Zhang, Xianfeng; Ning, Guang; Li, Xiaoying

    2011-01-01

    Highlights: → DAX1 is co-localized with FXR and interacts with FXR. → DAX1 acts as a negative regulator of FXR. → Three LXXLL motifs in the N-terminus of DAX1 were required. → DAX1 suppresses FXR transactivation by competing with co-activators. -- Abstract: Bile acid receptor FXR (farnesoid X receptor) is a key regulator of hepatic bile acid, glucose and lipid homeostasis through regulation of numerous genes involved in the process of bile acid, triglyceride and glucose metabolism. DAX1 (dosage-sensitive sex reversal adrenal hypoplasia congenital critical region on X chromosome, gene 1) is an atypical member of the nuclear receptor family due to lack of classical DNA-binding domains and acts primarily as a co-repressor of many nuclear receptors. Here, we demonstrated that DAX1 is co-localized with FXR in the nucleus and acted as a negative regulator of FXR through a physical interaction with FXR. Our study showed that over-expression of DAX1 down-regulated the expression of FXR target genes, whereas knockdown of DAX1 led to their up-regulation. Furthermore, three LXXLL motifs in the N-terminus of DAX1 were required for the full repression of FXR transactivation. In addition, our study characterized that DAX1 suppresses FXR transactivation via competing with co-activators such as SRC-1 and PGC-1α. In conclusion, DAX1 acts as a co-repressor to negatively modulate FXR transactivity.

  17. Molecular mechanism for the involvement of nuclear receptor FXR in HBV-associated hepatocellular carcinoma

    Directory of Open Access Journals (Sweden)

    Yong-dong Niu

    2011-08-01

    Full Text Available Farnesoid X receptor (FXR, also termed nuclear receptor NR1H4 is critically involved in the regulation of nascent bile formation and bile acid enterohepatic circulation. FXR and bile acids have been shown to play roles in liver regeneration and inflammatory responses. There is increasing evidence suggesting that FXR and the FXR signaling pathway are involved in the pathophysiology of a wide range of liver diseases, such as viral hepatitis, cirrhosis, and hepatocellular carcinoma (HCC. Here we discuss the latest discoveries of FXR functions with relevance to bile acid metabolism and HBV-associated HCC. More specifically, the goal of this review is to discuss the roles of FXR and bile acids in regulating HBV replication and how disregulation of the FXR-bile acid signaling pathway is involved in HBV-associated hepatocarcinogenesis.

  18. Upregulation of decorin by FXR in vascular smooth muscle cells

    International Nuclear Information System (INIS)

    He Fengtian; Zhang Qiuhong; Kuruba, Ramalinga; Gao Xiang; Li Jiang; Li Yong; Gong Wei; Jiang, Yu; Xie Wen; Li Song

    2008-01-01

    Decorin is a member of the family of small leucine-rich proteoglycans that are present in blood vessels and synthesized by vascular smooth muscle cells (VSMCs). Decorin plays complex roles in both normal vascular physiology and the pathogenesis of various types of vascular disorders. However, the mechanisms of regulation of decorin expression in vasculature are not clearly understood. Particularly little information is available about a role of nuclear receptors in the regulation of decorin expression. In the present study, we report that activation of vascular FXR by a specific ligand resulted in upregulation of decorin at the levels of both mRNA and protein. FXR appears to induce decorin expression at a transcriptional level because (1) upregulation of decorin mRNA expression was abolished by the treatment of a transcription inhibitor, actinomycin D; and (2) decorin promoter activity was significantly increased by activation of FXR. Functional analysis of human decorin promoter identified an imperfect inverted repeat DNA motif, IR8 (-2313TGGTCAtagtgtcaTGACCT-2294), as a likely FXR-responsive element that is involved in decorin regulation

  19. Chenodeoxycholic Acid Reduces Hypoxia Inducible Factor-1α Protein and Its Target Genes.

    Directory of Open Access Journals (Sweden)

    Yunwon Moon

    Full Text Available This study evaluated HIF-1α inhibitors under different hypoxic conditions, physiological hypoxia (5% O2 and severe hypoxia (0.1% O2. We found that chenodeoxy cholic acid (CDCA reduced the amount of HIF-1α protein only under physiological hypoxia but not under severe hypoxia without decreasing its mRNA level. By using a proteasome inhibitor MG132 and a translation inhibitor cyclohexamide, we showed that CDCA reduced HIF-1α protein by decreasing its translation but not by enhancing its degradation. The following findings indicated that farnesoid X receptor (FXR, a CDCA receptor and its target gene, Small heterodimer partner (SHP are not involved in this effect of CDCA. Distinctly from CDCA, MG132 prevented SHP and an exogenous FXR agonist, GW4064 from reducing HIF-1α protein. Furthermore a FXR antagonist, guggulsterone failed to prevent CDCA from decreasing HIF-1α protein. Furthermore, guggulsterone by itself reduced HIF-1α protein even in the presence of MG132. These findings suggested that CDCA and guggulsterone reduced the translation of HIF-1α in a mechanism which FXR and SHP are not involved. This study reveals novel therapeutic functions of traditional nontoxic drugs, CDCA and guggulsterone, as inhibitors of HIF-1α protein.

  20. Impact of global Fxr deficiency on experimental acute pancreatitis and genetic variation in the FXR locus in human acute pancreatitis

    NARCIS (Netherlands)

    Nijmeijer, Rian M.; Schaap, Frank G.; Smits, Alexander J. J.; Kremer, Andreas E.; Akkermans, Louis M. A.; Kroese, Alfons B. A.; Rijkers, Ger T.; Schipper, Marguerite E. I.; Verheem, André; Wijmenga, Cisca; Gooszen, Hein G.; van Erpecum, Karel J.

    2014-01-01

    Infectious complications often occur in acute pancreatitis, related to impaired intestinal barrier function, with prolonged disease course and even mortality as a result. The bile salt nuclear receptor farnesoid X receptor (FXR), which is expressed in the ileum, liver and other organs including the

  1. Immunohistochemical Expression of FXR1 in Canine Normal Tissues and Melanomas.

    Science.gov (United States)

    Nordio, Laura; Marques, Andreia T; Lecchi, Cristina; Luciano, Alberto M; Stefanello, Damiano; Giudice, Chiara

    2018-04-01

    Fragile X mental retardation-related protein 1 (FXR1) is a cytoplasmic RNA-binding protein highly conserved among vertebrates. It has been studied for its role in muscle development, inflammation, and tumorigenesis, being related, for example, to metastasizing behavior in human and canine uveal melanoma. Anti-FXR1 antibodies have never been validated in the canine species. To investigate FXR1 expression in canine melanocytic tumors, the present study tested two commercially available polyclonal anti-human FXR1 antibodies, raised in goat and rabbit, respectively. The cross-reactivity of the anti-FXR1 antibodies was assessed by Western blot analysis, and the protein was localized by IHC in a set of normal canine tissues and in canine melanocytic tumors (10 uveal and 10 oral). Western blot results demonstrated that the antibody raised in rabbit specifically recognized the canine FXR1, while the antibody raised in goat did not cross-react with this canine protein. FXR1 protein was immunodetected using rabbit anti-FXR1 antibody, in canine normal tissues with different levels of intensity and distribution. It was also detected in 10/10 uveal and 9/10 oral melanocytic tumors. The present study validated for the first time the use of anti-FXR1 antibody in dogs and highlighted different FXR1 protein expression in canine melanocytic tumors, the significance of which is undergoing further investigations.

  2. FXR silencing in human colon cancer by DNA methylation and KRAS signaling.

    Science.gov (United States)

    Bailey, Ann M; Zhan, Le; Maru, Dipen; Shureiqi, Imad; Pickering, Curtis R; Kiriakova, Galina; Izzo, Julie; He, Nan; Wei, Caimiao; Baladandayuthapani, Veerabhadran; Liang, Han; Kopetz, Scott; Powis, Garth; Guo, Grace L

    2014-01-01

    Farnesoid X receptor (FXR) is a bile acid nuclear receptor described through mouse knockout studies as a tumor suppressor for the development of colon adenocarcinomas. This study investigates the regulation of FXR in the development of human colon cancer. We used immunohistochemistry of FXR in normal tissue (n = 238), polyps (n = 32), and adenocarcinomas, staged I-IV (n = 43, 39, 68, and 9), of the colon; RT-quantitative PCR, reverse-phase protein array, and Western blot analysis in 15 colon cancer cell lines; NR1H4 promoter methylation and mRNA expression in colon cancer samples from The Cancer Genome Atlas; DNA methyltransferase inhibition; methyl-DNA immunoprecipitation (MeDIP); bisulfite sequencing; and V-Ki-ras2 Kirsten rat sarcoma viral oncogene homolog (KRAS) knockdown assessment to investigate FXR regulation in colon cancer development. Immunohistochemistry and quantitative RT-PCR revealed that expression and function of FXR was reduced in precancerous lesions and silenced in a majority of stage I-IV tumors. FXR expression negatively correlated with phosphatidylinositol-4, 5-bisphosphate 3 kinase signaling and the epithelial-to-mesenchymal transition. The NR1H4 promoter is methylated in ~12% colon cancer The Cancer Genome Atlas samples, and methylation patterns segregate with tumor subtypes. Inhibition of DNA methylation and KRAS silencing both increased FXR expression. FXR expression is decreased early in human colon cancer progression, and both DNA methylation and KRAS signaling may be contributing factors to FXR silencing. FXR potentially suppresses epithelial-to-mesenchymal transition and other oncogenic signaling cascades, and restoration of FXR activity, by blocking silencing mechanisms or increasing residual FXR activity, represents promising therapeutic options for the treatment of colon cancer.

  3. Discovery of Natural Products as Novel and Potent FXR Antagonists by Virtual Screening

    Science.gov (United States)

    Diao, Yanyan; Jiang, Jing; Zhang, Shoude; Li, Shiliang; Shan, Lei; Huang, Jin; Zhang, Weidong; Li, Honglin

    2018-04-01

    Farnesoid X receptor (FXR) is a member of nuclear receptor family involved in multiple physiological processes through regulating specific target genes. The critical role of FXR as a transcriptional regulator makes it a promising target for diverse diseases, especially those related to metabolic disorders such as diabetes and cholestasis. However, the underlying activation mechanism of FXR is still a blur owing to the absence of proper FXR modulators. To identify potential FXR modulators, an in-house natural product database (NPD) containing over 4000 compounds was screened by structure-based virtual screening strategy and subsequent hit-based similarity searching method. After the yeast two-hybrid (Y2H) assay, six natural products were identified as FXR antagonists which blocked the CDCA-induced SRC-1 association. The IC50 values of compounds 2a, a diterpene bearing polycyclic skeleton, and 3a, named daphneone with chain scaffold, are as low as 1.29 μM and 1.79 μM, respectively. Compared to the control compound guggulsterone (IC50 = 6.47 μM), compounds 2a and 3a displayed 5-fold and 3-fold higher antagonistic activities against FXR, respectively. Remarkably, the two representative compounds shared low topological similarities with other reported FXR antagonists. According to the putative binding poses, the molecular basis of these antagonists against FXR was also elucidated in this report.

  4. Comparative potency of obeticholic acid and natural bile acids on FXR in hepatic and intestinal in vitro cell models.

    Science.gov (United States)

    Zhang, Yuanyuan; LaCerte, Carl; Kansra, Sanjay; Jackson, Jonathan P; Brouwer, Kenneth R; Edwards, Jeffrey E

    2017-12-01

    Obeticholic acid (OCA) is a semisynthetic farnesoid X receptor (FXR) agonist, an analogue of chenodeoxycholic acid (CDCA) which is indicated for the treatment of primary biliary cholangitis (PBC) in combination with ursodeoxycholic acid (UDCA). OCA efficiently inhibits bile acid synthesis and promotes bile acid efflux via activating FXR-mediated mechanisms in a physiologically relevant in vitro cell system, Sandwich-cultured Transporter Certified ™ human primary hepatocytes (SCHH). The study herein evaluated the effects of UDCA alone or in combination with OCA in SCHH. UDCA (≤100 μmol/L) alone did not inhibit CYP7A1 mRNA, and thus, no reduction in the endogenous bile acid pool observed. UDCA ≤100 μmol/L concomitantly administered with 0.1 μmol/L OCA had no effect on bile acid synthesis beyond what was observed with OCA alone. Furthermore, this study evaluated human Caco-2 cells (clone C2BBe1) as in vitro intestinal models. Glycine conjugate of OCA increased mRNA levels of FXR target genes in Caco-2 cells, FGF-19, SHP, OSTα/β, and IBABP, but not ASBT, in a concentration-dependent manner, while glycine conjugate of UDCA had no effect on the expression of these genes. The results suggested that UDCA ≤100 μmol/L did not activate FXR in human primary hepatocytes or intestinal cell line Caco-2. Thus, co-administration of UDCA with OCA did not affect OCA-dependent pharmacological effects. © 2017 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.

  5. The LLNL Flash X-Ray Induction Linear Accelerator (FXR)

    International Nuclear Information System (INIS)

    Multhauf, L G

    2002-01-01

    The FXR is an induction linear accelerator used for high-speed radiography at the Lawrence Livermore National Laboratory's Experimental Test Site. It was designed specifically for the radiography of very thick explosive objects. Since its completion in 1982, it has been very actively used for a large variety of explosives tests, and has been periodically upgraded to achieve higher performance. Upgrades have addressed machine reliability, radiographic sensitivity and resolution, two-frame imaging by double pulsing improvements that are described in detail in the paper. At the same time, the facility in which it was installed has also been extensively upgraded, first by adding space for optical and interferometric diagnostics, and more recently by adding a containment chamber to prevent the environmental dispersal of hazardous and radioactive materials. The containment addition also further expands space for new non-radiographic diagnostics. The new Contained Firing Facility is still in the process of activation. At the same time, FXR is continuing to undergo modifications aimed primarily at further increasing radiographic resolution and sensitivity, and at improving double-pulsed performance

  6. Ageing Fxr deficient mice develop increased energy expenditure, improved glucose control and liver damage resembling NASH.

    Directory of Open Access Journals (Sweden)

    Mikael Bjursell

    Full Text Available Nuclear receptor subfamily 1, group H, member 4 (Nr1h4, FXR is a bile acid activated nuclear receptor mainly expressed in the liver, intestine, kidney and adrenal glands. Upon activation, the primary function is to suppress cholesterol 7 alpha-hydroxylase (Cyp7a1, the rate-limiting enzyme in the classic or neutral bile acid synthesis pathway. In the present study, a novel Fxr deficient mouse line was created and studied with respect to metabolism and liver function in ageing mice fed chow diet. The Fxr deficient mice were similar to wild type mice in terms of body weight, body composition, energy intake and expenditure as well as behaviours at a young age. However, from 15 weeks of age and onwards, the Fxr deficient mice had almost no body weight increase up to 39 weeks of age mainly because of lower body fat mass. The lower body weight gain was associated with increased energy expenditure that was not compensated by increased food intake. Fasting levels of glucose and insulin were lower and glucose tolerance was improved in old and lean Fxr deficient mice. However, the Fxr deficient mice displayed significantly increased liver weight, steatosis, hepatocyte ballooning degeneration and lobular inflammation together with elevated plasma levels of ALT, bilirubin and bile acids, findings compatible with non-alcoholic steatohepatitis (NASH and cholestasis. In conclusion, ageing Fxr deficient mice display late onset leanness associated with elevated energy expenditure and improved glucose control but develop severe NASH-like liver pathology.

  7. Ageing Fxr deficient mice develop increased energy expenditure, improved glucose control and liver damage resembling NASH.

    Science.gov (United States)

    Bjursell, Mikael; Wedin, Marianne; Admyre, Therése; Hermansson, Majlis; Böttcher, Gerhard; Göransson, Melker; Lindén, Daniel; Bamberg, Krister; Oscarsson, Jan; Bohlooly-Y, Mohammad

    2013-01-01

    Nuclear receptor subfamily 1, group H, member 4 (Nr1h4, FXR) is a bile acid activated nuclear receptor mainly expressed in the liver, intestine, kidney and adrenal glands. Upon activation, the primary function is to suppress cholesterol 7 alpha-hydroxylase (Cyp7a1), the rate-limiting enzyme in the classic or neutral bile acid synthesis pathway. In the present study, a novel Fxr deficient mouse line was created and studied with respect to metabolism and liver function in ageing mice fed chow diet. The Fxr deficient mice were similar to wild type mice in terms of body weight, body composition, energy intake and expenditure as well as behaviours at a young age. However, from 15 weeks of age and onwards, the Fxr deficient mice had almost no body weight increase up to 39 weeks of age mainly because of lower body fat mass. The lower body weight gain was associated with increased energy expenditure that was not compensated by increased food intake. Fasting levels of glucose and insulin were lower and glucose tolerance was improved in old and lean Fxr deficient mice. However, the Fxr deficient mice displayed significantly increased liver weight, steatosis, hepatocyte ballooning degeneration and lobular inflammation together with elevated plasma levels of ALT, bilirubin and bile acids, findings compatible with non-alcoholic steatohepatitis (NASH) and cholestasis. In conclusion, ageing Fxr deficient mice display late onset leanness associated with elevated energy expenditure and improved glucose control but develop severe NASH-like liver pathology.

  8. The bile acids, deoxycholic acid and ursodeoxycholic acid, regulate colonic epithelial wound healing.

    Science.gov (United States)

    Mroz, Magdalena S; Lajczak, Natalia K; Goggins, Bridie J; Keely, Simon; Keely, Stephen J

    2018-03-01

    The intestinal epithelium constitutes an innate barrier which, upon injury, undergoes self-repair processes known as restitution. Although bile acids are known as important regulators of epithelial function in health and disease, their effects on wound healing processes are not yet clear. Here we set out to investigate the effects of the colonic bile acids, deoxycholic acid (DCA) and ursodeoxycholic acid (UDCA), on epithelial restitution. Wound healing in T 84 cell monolayers grown on transparent, permeable supports was assessed over 48 h with or without bile acids. Cell migration was measured in Boyden chambers. mRNA and protein expression were measured by RT-PCR and Western blotting. DCA (50-150 µM) significantly inhibited wound closure in cultured epithelial monolayers and attenuated cell migration in Boyden chamber assays. DCA also induced nuclear accumulation of the farnesoid X receptor (FXR), whereas an FXR agonist, GW4064 (10 µM), inhibited wound closure. Both DCA and GW4064 attenuated the expression of CFTR Cl - channels, whereas inhibition of CFTR activity with either CFTR- inh -172 (10 µM) or GlyH-101 (25 µM) also prevented wound healing. Promoter/reporter assays revealed that FXR-induced downregulation of CFTR is mediated at the transcriptional level. In contrast, UDCA (50-150 µM) enhanced wound healing in vitro and prevented the effects of DCA. Finally, DCA inhibited and UDCA promoted mucosal healing in an in vivo mouse model. In conclusion, these studies suggest bile acids are important regulators of epithelial wound healing and are therefore good targets for development of new drugs to modulate intestinal barrier function in disease treatment. NEW & NOTEWORTHY The secondary bile acid, deoxycholic acid, inhibits colonic epithelial wound healing, an effect which appears to be mediated by activation of the nuclear bile acid receptor, FXR, with subsequent downregulation of CFTR expression and activity. In contrast, ursodeoxycholic acid promotes

  9. Hormesis in Cholestatic Liver Disease; Preconditioning with Low Bile Acid Concentrations Protects against Bile Acid-Induced Toxicity.

    Directory of Open Access Journals (Sweden)

    Esther M Verhaag

    Full Text Available Cholestasis is characterized by accumulation of bile acids and inflammation, causing hepatocellular damage. Still, liver damage markers are highest in acute cholestasis and drop when this condition becomes chronic, indicating that hepatocytes adapt towards the hostile environment. This may be explained by a hormetic response in hepatocytes that limits cell death during cholestasis.To investigate the mechanisms that underlie the hormetic response that protect hepatocytes against experimental cholestatic conditions.HepG2.rNtcp cells were preconditioned (24 h with sub-apoptotic concentrations (0.1-50 μM of various bile acids, the superoxide donor menadione, TNF-α or the Farsenoid X Receptor agonist GW4064, followed by a challenge with the apoptosis-inducing bile acid glycochenodeoxycholic acid (GCDCA; 200 μM for 4 h, menadione (50 μM, 6 h or cytokine mixture (CM; 6 h. Levels of apoptotic and necrotic cell death, mRNA expression of the bile salt export pump (ABCB11 and bile acid sensors, as well as intracellular GCDCA levels were analyzed.Preconditioning with the pro-apoptotic bile acids GCDCA, taurocholic acid, or the protective bile acids (tauroursodeoxycholic acid reduced GCDCA-induced caspase-3/7 activity in HepG2.rNtcp cells. Bile acid preconditioning did not induce significant levels of necrosis in GCDCA-challenged HepG2.rNtcp cells. In contrast, preconditioning with cholic acid, menadione or TNF-α potentiated GCDCA-induced apoptosis. GCDCA preconditioning specifically reduced GCDCA-induced cell death and not CM- or menadione-induced apoptosis. The hormetic effect of GCDCA preconditioning was concentration- and time-dependent. GCDCA-, CDCA- and GW4064- preconditioning enhanced ABCB11 mRNA levels, but in contrast to the bile acids, GW4064 did not significantly reduce GCDCA-induced caspase-3/7 activity. The GCDCA challenge strongly increased intracellular levels of this bile acid, which was not lowered by GCDCA

  10. An Improved SF6 System for the FXR Induction Linac Blumlein Switches

    International Nuclear Information System (INIS)

    DeHope, W; Kihara, R; Griffin, K L; Ong, M; Ross, T

    2007-01-01

    The now-mature FXR (Flash X-Ray) radiographic facility at Lawrence Livermore National Laboratory will be briefly described with emphasis on its pulsed power system. The heart of each accelerating cell's pulse forming Blumlein is it's sulfur hexafluoride-based triggered closing switch. FXR's recent upgrade to a recirculating SF 6 gas reclamation system will be described and the resulting accelerator performance and reliability improvements documented. This was accompanied by a detailed switch breakdown study on FXR's Test Stand and the recent analysis of the resulting statistics will be shown

  11. Bile Acids, FXR, and Metabolic Effects of Bariatric Surgery

    Directory of Open Access Journals (Sweden)

    Olivier F. Noel

    2016-01-01

    Full Text Available Overweight and obesity represent major risk factors for diabetes and related metabolic diseases. Obesity is associated with a chronic and progressive inflammatory response leading to the development of insulin resistance and type 2 diabetes (T2D mellitus, although the precise mechanism mediating this inflammatory process remains poorly understood. The most effective intervention for the treatment of obesity, bariatric surgery, leads to glucose normalization and remission of T2D. Recent work in both clinical studies and animal models supports bile acids (BAs as key mediators of these effects. BAs are involved in lipid and glucose homeostasis primarily via the farnesoid X receptor (FXR transcription factor. BAs are also involved in regulating genes involved in inflammation, obesity, and lipid metabolism. Here, we review the novel role of BAs in bariatric surgery and the intersection between BAs and immune, obesity, weight loss, and lipid metabolism genes.

  12. Nutrient-sensing nuclear receptors PPARα and FXR control liver energy balance.

    Science.gov (United States)

    Preidis, Geoffrey A; Kim, Kang Ho; Moore, David D

    2017-04-03

    The nuclear receptors PPARα (encoded by NR1C1) and farnesoid X receptor (FXR, encoded by NR1H4) are activated in the liver in the fasted and fed state, respectively. PPARα activation induces fatty acid oxidation, while FXR controls bile acid homeostasis, but both nuclear receptors also regulate numerous other metabolic pathways relevant to liver energy balance. Here we review evidence that they function coordinately to control key nutrient pathways, including fatty acid oxidation and gluconeogenesis in the fasted state and lipogenesis and glycolysis in the fed state. We have also recently reported that these receptors have mutually antagonistic impacts on autophagy, which is induced by PPARα but suppressed by FXR. Secretion of multiple blood proteins is a major drain on liver energy and nutrient resources, and we present preliminary evidence that the liver secretome may be directly suppressed by PPARα, but induced by FXR. Finally, previous studies demonstrated a striking deficiency in bile acid levels in malnourished mice that is consistent with results in malnourished children. We present evidence that hepatic targets of PPARα and FXR are dysregulated in chronic undernutrition. We conclude that PPARα and FXR function coordinately to integrate liver energy balance.

  13. FXR blocks the growth of liver cancer cells through inhibiting mTOR-s6K pathway

    International Nuclear Information System (INIS)

    Huang, Xiongfei; Zeng, Yeting; Wang, Xinrui; Ma, Xiaoxiao; Li, Qianqian; Li, Ningbo; Su, Hongying; Huang, Wendong

    2016-01-01

    The nuclear receptor Farnesoid X Receptor (FXR) is likely a tumor suppressor in liver tissue but its molecular mechanism of suppression is not well understood. In this study, the gene expression profile of human liver cancer cells was investigated by microarray. Bioinformatics analysis of these data revealed that FXR might regulate the mTOR/S6K signaling pathway. This was confirmed by altering the expression level of FXR in liver cancer cells. Overexpression of FXR prevented the growth of cells and induced cell cycle arrest, which was enhanced by the mTOR/S6K inhibitor rapamycin. FXR upregulation also intensified the inhibition of cell growth by rapamycin. Downregulation of FXR produced the opposite effect. Finally, we found that ectopic expression of FXR in SK-Hep-1 xenografts inhibits tumor growth and reduces expression of the phosphorylated protein S6K. Taken together, our data provide the first evidence that FXR suppresses proliferation of human liver cancer cells via the inhibition of the mTOR/S6K signaling pathway. FXR expression can be used as a biomarker of personalized mTOR inhibitor treatment assessment for liver cancer patients. -- Highlights: •FXR inhibits the proliferation of liver cancer cells by prolonging G0/G1 phase. •Microarray results indicate that mTOR-S6k signaling is involved in cellular processes in which FXR plays an important role. •FXR blocks the growth of liver cancer cells via the inhibition of the mTOR/S6K signaling pathway in vitro and in vivo.

  14. FXR blocks the growth of liver cancer cells through inhibiting mTOR-s6K pathway

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Xiongfei, E-mail: xiongfeihuang@hotmail.com [Department of Pathology and Institute of Oncology, Preclinical School, Fujian Medical University, Fuzhou 350108, Fujian (China); Key Laboratory of Ministry of Education for Gastrointestinal Cancer, Fujian Medical University, Fuzhou 350108, Fujian (China); Zeng, Yeting [Department of Pathology and Institute of Oncology, Preclinical School, Fujian Medical University, Fuzhou 350108, Fujian (China); Wang, Xinrui [Department of Biochemistry and Molecular Biology, Fujian Medical University, Fuzhou 350108, Fujian (China); Ma, Xiaoxiao [Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope, CA 91010 (United States); Li, Qianqian; Li, Ningbo; Su, Hongying [Department of Pathology and Institute of Oncology, Preclinical School, Fujian Medical University, Fuzhou 350108, Fujian (China); Huang, Wendong [Department of Diabetes Complications and Metabolism, Diabetes & Metabolism Research Institute, Beckman Research Institute, City of Hope, CA 91010 (United States)

    2016-05-27

    The nuclear receptor Farnesoid X Receptor (FXR) is likely a tumor suppressor in liver tissue but its molecular mechanism of suppression is not well understood. In this study, the gene expression profile of human liver cancer cells was investigated by microarray. Bioinformatics analysis of these data revealed that FXR might regulate the mTOR/S6K signaling pathway. This was confirmed by altering the expression level of FXR in liver cancer cells. Overexpression of FXR prevented the growth of cells and induced cell cycle arrest, which was enhanced by the mTOR/S6K inhibitor rapamycin. FXR upregulation also intensified the inhibition of cell growth by rapamycin. Downregulation of FXR produced the opposite effect. Finally, we found that ectopic expression of FXR in SK-Hep-1 xenografts inhibits tumor growth and reduces expression of the phosphorylated protein S6K. Taken together, our data provide the first evidence that FXR suppresses proliferation of human liver cancer cells via the inhibition of the mTOR/S6K signaling pathway. FXR expression can be used as a biomarker of personalized mTOR inhibitor treatment assessment for liver cancer patients. -- Highlights: •FXR inhibits the proliferation of liver cancer cells by prolonging G0/G1 phase. •Microarray results indicate that mTOR-S6k signaling is involved in cellular processes in which FXR plays an important role. •FXR blocks the growth of liver cancer cells via the inhibition of the mTOR/S6K signaling pathway in vitro and in vivo.

  15. Estimating The Reliability of the Lawrence Livermore National Laboratory (LLNL) Flash X-ray (FXR) Machine

    International Nuclear Information System (INIS)

    Ong, M M; Kihara, R; Zentler, J M; Kreitzer, B R; DeHope, W J

    2007-01-01

    At Lawrence Livermore National Laboratory (LLNL), our flash X-ray accelerator (FXR) is used on multi-million dollar hydrodynamic experiments. Because of the importance of the radiographs, FXR must be ultra-reliable. Flash linear accelerators that can generate a 3 kA beam at 18 MeV are very complex. They have thousands, if not millions, of critical components that could prevent the machine from performing correctly. For the last five years, we have quantified and are tracking component failures. From this data, we have determined that the reliability of the high-voltage gas-switches that initiate the pulses, which drive the accelerator cells, dominates the statistics. The failure mode is a single-switch pre-fire that reduces the energy of the beam and degrades the X-ray spot-size. The unfortunate result is a lower resolution radiograph. FXR is a production machine that allows only a modest number of pulses for testing. Therefore, reliability switch testing that requires thousands of shots is performed on our test stand. Study of representative switches has produced pre-fire statistical information and probability distribution curves. This information is applied to FXR to develop test procedures and determine individual switch reliability using a minimal number of accelerator pulses

  16. Splenic dendritic cell involvement in FXR-mediated amelioration of DSS colitis

    NARCIS (Netherlands)

    Massafra, Vittoria; Ijssennagger, Noortje; Plantinga, Maud; Milona, Alexandra; Ramos Pittol, José M.; Boes, Marianne; van Mil, Saskia W C

    2016-01-01

    Inflammatory Bowel Disease (IBD) is a multifactorial disorder involving dysregulation of the immune response and bacterial translocation through the intestinal mucosal barrier. Previously, we have shown that activation of the bile acid sensor Farnesoid X Receptor (FXR), which belongs to the family

  17. Farnesoid X Receptor Agonist Treatment Alters Bile Acid Metabolism but Exacerbates Liver Damage in a Piglet Model of Short-Bowel Syndrome.

    Science.gov (United States)

    Pereira-Fantini, Prue M; Lapthorne, Susan; Gahan, Cormac G M; Joyce, Susan A; Charles, Jenny; Fuller, Peter J; Bines, Julie E

    2017-07-01

    Options for the prevention of short-bowel syndrome-associated liver disease (SBS-ALDs) are limited and often ineffective. The farnesoid X receptor (FXR) is a newly emerging pharmaceutical target and FXR agonists have been shown to ameliorate cholestasis and metabolic disorders. The aim of this study was to assess the efficacy of obeticholic acid (OCA) treatment in preventing SBS-ALDs. Piglets underwent 75% small-bowel resection (SBS) or sham surgery (sham) and were assigned to either a daily dose of OCA (2.4 mg/kg/day) or were untreated. Clinical measures included weight gain and stool studies. Histologic features were assessed. Ultraperformance liquid chromatography tandem mass spectrometry was used to determine bile acid composition in end point bile and portal serum samples. Gene expression of key FXR targets was assessed in intestinal and hepatic tissues via quantitative polymerase chain reaction. OCA-treated SBS piglets showed decreased stool fat and altered liver histology when compared with nontreated SBS piglets. OCA prevented SBS-associated taurine depletion, however, further analysis of bile and portal serum samples indicated that OCA did not prevent SBS-associated alterations in bile acid composition. The expression of FXR target genes involved in bile acid transport and synthesis increased within the liver of SBS piglets after OCA administration whereas, paradoxically, intestinal expression of FXR target genes were decreased by OCA administration. Administration of OCA in SBS reduced fat malabsorption and altered bile acid composition, but did not prevent the development of SBS-ALDs. We postulate that extensive small resection impacts the ability of the remnant intestine to respond to FXR activation.

  18. Validation of anti-FXR1 antibodies in the canine species and application to an immunohistochemical study of canine oral melanomas

    Directory of Open Access Journals (Sweden)

    Laura Nordio

    2017-05-01

    Full Text Available FXR1 (Fragile X mental retardation-related protein 1 is a cytoplasmic RNA binding protein, which genetic expression has been related to metastatic potential in human melanoma. The aims of the present study were: the validation of two commercially available clones of polyclonal anti-human FXR1 antibody in dogs; their application to investigate FXR1 expression in a group of canine oral melanomas. Anti-FXR1 antibody was not previously validated in the canine species. Two different commercially available polyclonal anti-FXR1 antibodies (respectively made in goat and in rabbit were used. FXR1 protein in canine serum was identified by western blot after SDS-PAGE, using human serum as control. FXR1 immunohistochemical expression was tested in a series of normal tissues, that are expected to express FXR1, and in 31 cases of oral melanomas. The final immunohistochemical protocol used heat-induced unmasking and overnight incubation. FXR1 protein bands in canine serum were detected by tested antibodies, in a more specific way by the rabbit antibody. FXR1 immunohistochemical staining was positive in all tested organs, with different levels of expression. FXR1 was also expressed in 31/31 tested melanomas, with variable intensity and percentage of positive cells (Figure 1. Equal results were achieved with the two antibodies in 8 cases of melanoma, whereas there were variable differences in 22, and one case stained only with goat antibody. The rabbit antibody gave less background staining. This study validated anti-FXR1 antibodies for use in the canine species. This protein was expressed in various normal tissues, as well as in the tested neoplasms. Significance of different level of expression is undergoing evaluation with further studies.

  19. Mutations in the nuclear bile acid receptor FXR cause progressive familial intrahepatic cholestasis

    Science.gov (United States)

    Gomez-Ospina, Natalia; Potter, Carol J.; Xiao, Rui; Manickam, Kandamurugu; Kim, Mi-Sun; Kim, Kang Ho; Shneider, Benjamin L.; Picarsic, Jennifer L.; Jacobson, Theodora A.; Zhang, Jing; He, Weimin; Liu, Pengfei; Knisely, A. S.; Finegold, Milton J.; Muzny, Donna M.; Boerwinkle, Eric; Lupski, James R.; Plon, Sharon E.; Gibbs, Richard A.; Eng, Christine M.; Yang, Yaping; Washington, Gabriel C.; Porteus, Matthew H.; Berquist, William E.; Kambham, Neeraja; Singh, Ravinder J.; Xia, Fan; Enns, Gregory M.; Moore, David D.

    2016-01-01

    Neonatal cholestasis is a potentially life-threatening condition requiring prompt diagnosis. Mutations in several different genes can cause progressive familial intrahepatic cholestasis, but known genes cannot account for all familial cases. Here we report four individuals from two unrelated families with neonatal cholestasis and mutations in NR1H4, which encodes the farnesoid X receptor (FXR), a bile acid-activated nuclear hormone receptor that regulates bile acid metabolism. Clinical features of severe, persistent NR1H4-related cholestasis include neonatal onset with rapid progression to end-stage liver disease, vitamin K-independent coagulopathy, low-to-normal serum gamma-glutamyl transferase activity, elevated serum alpha-fetoprotein and undetectable liver bile salt export pump (ABCB11) expression. Our findings demonstrate a pivotal function for FXR in bile acid homeostasis and liver protection. PMID:26888176

  20. Investigation of JI and DI CMOS FXR response at different spectral energies

    International Nuclear Information System (INIS)

    Honnold, V.R.; Goldberg, M.; Schreiner, W.A.; Witteles, A.A.

    1975-01-01

    The transient response of both junction isolated (JI) and dielectrically isolated (DI) CMOS circuits has been investigated in three FXR environments of differing energy spectrums. The offset recovery times have been measured and analyzed for both structures. It is shown that while the DI circuit (HD4007) did not exhibit a four layer type latchup action, its transient response persisted for a time longer than is expected for this type of device. A possible mechanism for this observed response is developed and discussed. JI circuits (CD4007) exposed under the same conditions exhibited four layer device action and one sample at low spectral energies latched-up. The conditions for the latchup to occur including the four layer device paths are discussed. Finally, the dependence of the x-ray transient response on the spectral energy is considered. For the lower energy FXR source, latchup was observed in a CD4007 sample. This latchup was not observed at more than double the dose rate when a high energy FXR was used. This result is attributed to dose enhancement, and a device enhancement factor may also be involved. The dose enhancement factor is estimated from the work of Long, and points up the importance of accounting for the spectral energy content in simulating a given nuclear threat spectrum

  1. Preliminary Structure-Activity Relationship on Theonellasterol, a New Chemotype of FXR Antagonist, from the Marine Sponge Theonella swinhoei

    Directory of Open Access Journals (Sweden)

    Stefano Fiorucci

    2012-11-01

    Full Text Available Using theonellasterol as a novel FXR antagonist hit, we prepared a series of semi-synthetic derivatives in order to gain insight into the structural requirements for exhibiting antagonistic activity. These derivatives are characterized by modification at the exocyclic carbon-carbon double bond at C-4 and at the hydroxyl group at C-3 and were prepared from theonellasterol using simple reactions. Pharmacological investigation showed that the introduction of a hydroxyl group at C-4 as well as the oxidation at C-3 with or without concomitant modification at the exomethylene functionality preserve the ability of theonellasterol to inhibit FXR transactivation caused by CDCA. Docking analysis showed that the placement of these molecules in the FXR-LBD is well stabilized when on ring A functional groups, able to form hydrogen bonds and π interactions, are present.

  2. FXR is a molecular target for the effects of vertical sleeve gastrectomy

    DEFF Research Database (Denmark)

    Ryan, Karen K; Tremaroli, Valentina; Clemmensen, Christoffer

    2014-01-01

    Bariatric surgical procedures, such as vertical sleeve gastrectomy (VSG), are at present the most effective therapy for the treatment of obesity, and are associated with considerable improvements in co-morbidities, including type-2 diabetes mellitus. The underlying molecular mechanisms contributing......-X receptor, also known as NR1H4). We therefore examined the results of VSG surgery applied to mice with diet-induced obesity and targeted genetic disruption of FXR. Here we demonstrate that the therapeutic value of VSG does not result from mechanical restriction imposed by a smaller stomach. Rather, VSG...

  3. Expression of the bile acid receptor FXR in Barrett's esophagus and enhancement of apoptosis by guggulsterone in vitro

    Directory of Open Access Journals (Sweden)

    Frossard Jean-Louis

    2006-10-01

    Full Text Available Abstract Background Barrett's esophagus, a risk factor for esophageal adenocarcinoma, is associated with reflux disease. The aim of this study was to assess the expression of bile acid receptors in the esophagus (normal, esophagitis, Barrett's esophagus and adenocarcinoma and to investigate their possible function. Results the expression of the bile acid receptors FXR and VDR in esophageal biopsies from patients with a normal mucosa, esophagitis, Barrett's esophagus or adenocarcinoma (n = 6 per group and in cell lines derived from Barrett's esophagus and esophageal adenocarcinoma, was assessed by real time Q-PCR and immunohistochemistry. The effect of guggulsterone, an antagonist of bile acid receptors, on apoptosis of Barrett's esophagus-derived cells was assessed morphologically, by flow cytometry and by measuring caspase 3 activity. The expression of FXR was increased in esophagitis, Barrett's esophagus and adenocarcinoma compared to normal mucosa by a mean of 44, 84 and 16, respectively. Immunohistochemistry showed a weak expression in normal esophagus, a strong focal reactivity in Barrett's esophagus, and was negative in adenocarcinoma. VDR expression did not significantly differ between groups. In cell cultures, the expression of FXR was high in Barrett's esophagus-derived cells and almost undetectable in adenocarcinoma-derived cells, whereas VDR expression in these cell lines was not significantly different. In vitro treatment with guggulsterone was associated with a significant increase in the percentage of apoptotic cells and of the caspase 3 activity. Conclusion the bile acid receptor FXR is significantly overexpressed in Barrett's esophagus compared to normal mucosa, esophagitis and esophageal adenocarcinoma. The induction of apoptosis by guggulsterone in a Barrett's esophagus-derived cell line suggests that FXR may contribute to the regulation of apoptosis.

  4. Modification on ursodeoxycholic acid (UDCA) scaffold. discovery of bile acid derivatives as selective agonists of cell-surface G-protein coupled bile acid receptor 1 (GP-BAR1).

    Science.gov (United States)

    Sepe, Valentina; Renga, Barbara; Festa, Carmen; D'Amore, Claudio; Masullo, Dario; Cipriani, Sabrina; Di Leva, Francesco Saverio; Monti, Maria Chiara; Novellino, Ettore; Limongelli, Vittorio; Zampella, Angela; Fiorucci, Stefano

    2014-09-25

    Bile acids are signaling molecules interacting with the nuclear receptor FXR and the G-protein coupled receptor 1 (GP-BAR1/TGR5). GP-BAR1 is a promising pharmacological target for the treatment of steatohepatitis, type 2 diabetes, and obesity. Endogenous bile acids and currently available semisynthetic bile acids are poorly selective toward GP-BAR1 and FXR. Thus, in the present study we have investigated around the structure of UDCA, a clinically used bile acid devoid of FXR agonist activity, to develop a large family of side chain modified 3α,7β-dihydroxyl cholanoids that selectively activate GP-BAR1. In vivo and in vitro pharmacological evaluation demonstrated that administration of compound 16 selectively increases the expression of pro-glucagon 1, a GP-BAR1 target, in the small intestine, while it had no effect on FXR target genes in the liver. Further, compound 16 results in a significant reshaping of bile acid pool in a rodent model of cholestasis. These data demonstrate that UDCA is a useful scaffold to generate novel and selective steroidal ligands for GP-BAR1.

  5. Fragile X Proteins FMRP and FXR2P Control Synaptic GluA1 Expression and Neuronal Maturation via Distinct Mechanisms

    Directory of Open Access Journals (Sweden)

    Weixiang Guo

    2015-06-01

    Full Text Available Fragile X mental retardation protein (FMRP and its autosomal paralog FXR2P are selective neuronal RNA-binding proteins, and mice that lack either protein exhibit cognitive deficits. Although double-mutant mice display more severe learning deficits than single mutants, the molecular mechanism behind this remains unknown. In the present study, we discovered that FXR2P (also known as FXR2 is important for neuronal dendritic development. FMRP and FXR2P additively promote the maturation of new neurons by regulating a common target, the AMPA receptor GluA1, but they do so via distinct mechanisms: FXR2P binds and stabilizes GluA1 mRNA and enhances subsequent protein expression, whereas FMRP promotes GluA1 membrane delivery. Our findings unveil important roles for FXR2P and GluA1 in neuronal development, uncover a regulatory mechanism of GluA1, and reveal a functional convergence between fragile X proteins in neuronal development.

  6. Glutamate receptor agonists

    DEFF Research Database (Denmark)

    Vogensen, Stine Byskov; Greenwood, Jeremy R; Bunch, Lennart

    2011-01-01

    The neurotransmitter (S)-glutamate [(S)-Glu] is responsible for most of the excitatory neurotransmission in the central nervous system. The effect of (S)-Glu is mediated by both ionotropic and metabotropic receptors. Glutamate receptor agonists are generally a-amino acids with one or more...... stereogenic centers due to strict requirements in the agonist binding pocket of the activated state of the receptor. By contrast, there are many examples of achiral competitive antagonists. The present review addresses how stereochemistry affects the activity of glutamate receptor ligands. The review focuses...... mainly on agonists and discusses stereochemical and conformational considerations as well as biostructural knowledge of the agonist binding pockets, which is useful in the design of glutamate receptor agonists. Examples are chosen to demonstrate how stereochemistry not only determines how the agonist...

  7. Superior reductions in hepatic steatosis and fibrosis with co-administration of a glucagon-like peptide-1 receptor agonist and obeticholic acid in mice.

    Science.gov (United States)

    Jouihan, Hani; Will, Sarah; Guionaud, Silvia; Boland, Michelle L; Oldham, Stephanie; Ravn, Peter; Celeste, Anthony; Trevaskis, James L

    2017-11-01

    Nonalcoholic steatohepatitis (NASH) is an unmet need associated with metabolic syndrome. There are no approved therapies for NASH; however, glucagon-like peptide-1 receptor (GLP-1R) and farnesoid-X receptor (FXR) agonists are promising drug targets. We investigated the therapeutic effects of co-administration of a GLP-1R agonist, IP118, with FXR agonist obeticholic acid (OCA) in mice. OCA and IP118 alone and in combination were sub-chronically administered to Lep ob /Lep ob mice with diet-induced NASH or diet-induced obese (DIO) mice. Metabolic (body weight and glucose) and liver (biochemical and histological) endpoints were assessed. NASH severity in Lep ob /Lep ob mice was graded using a customized integrated scoring system. OCA reduced liver weight and lipid in NASH mice (both by -17%) but had no effect on plasma ALT or AST levels. In contrast, IP118 significantly reduced liver weight (-21%), liver lipid (-15%), ALT (-29%), and AST (-27%). The combination of OCA + IP118 further reduced liver weight (-29%), liver lipid (-22%), ALT (-39%), and AST (-36%). Combination therapy was superior to monotherapies in reducing hepatic steatosis, inflammation, and fibrosis. Hepatic improvements with IP118 and OCA + IP118 were associated with reduced body weight (-4.3% and -3.5% respectively) and improved glycemic control in OCA + IP118-treated mice. In DIO mice, OCA + IP118 co-administration reduced body weight (-25.3%) to a greater degree than IP118 alone (-12.5%) and further improved glucose tolerance and reduced hepatic lipid. Our data suggest a complementary or synergistic therapeutic effect of GLP-1R and FXR agonism in mouse models of metabolic disease and NASH. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

  8. Identification of a mouse Lactobacillus johnsonii strain with deconjugase activity against the FXR antagonist T-β-MCA.

    Directory of Open Access Journals (Sweden)

    Michael DiMarzio

    Full Text Available Bile salt hydrolase (BSH activity against the bile acid tauro-beta-muricholic acid (T-β-MCA was recently reported to mediate host bile acid, glucose, and lipid homeostasis via the farnesoid X receptor (FXR signaling pathway. An earlier study correlated decreased Lactobacillus abundance in the cecum with increased concentrations of intestinal T-β-MCA, an FXR antagonist. While several studies have characterized BSHs in lactobacilli, deconjugation of T-β-MCA remains poorly characterized among members of this genus, and therefore it was unclear what strain(s were responsible for this activity. Here, a strain of L. johnsonii with robust BSH activity against T-β-MCA in vitro was isolated from the cecum of a C57BL/6J mouse. A screening assay performed on a collection of 14 Lactobacillus strains from nine different species identified BSH substrate specificity for T-β-MCA only in two of three L. johnsonii strains. Genomic analysis of the two strains with this BSH activity revealed the presence of three bsh genes that are homologous to bsh genes in the previously sequenced human-associated strain L. johnsonii NCC533. Heterologous expression of several bsh genes in E. coli followed by enzymatic assays revealed broad differences in substrate specificity even among closely related bsh homologs, and suggests that the phylogeny of these enzymes does not closely correlate with substrate specificity. Predictive modeling allowed us to propose a potential mechanism driving differences in BSH activity for T-β-MCA in these homologs. Our data suggests that L. johnsonii regulates T-β-MCA levels in the mouse intestinal environment, and that this species may play a central role in FXR signaling in the mouse.

  9. Inactivation of Adenomatous Polyposis Coli Reduces Bile Acid/Farnesoid X Receptor Expression through Fxr gene CpG Methylation in Mouse Colon Tumors and Human Colon Cancer Cells.

    Science.gov (United States)

    Selmin, Ornella I; Fang, Changming; Lyon, Adam M; Doetschman, Tom C; Thompson, Patricia A; Martinez, Jesse D; Smith, Jeffrey W; Lance, Peter M; Romagnolo, Donato F

    2016-02-01

    The farnesoid X receptor (FXR) regulates bile acid (BA) metabolism and possesses tumor suppressor functions. FXR expression is reduced in colorectal tumors of subjects carrying inactivated adenomatous polyposis coli (APC). Identifying the mechanisms responsible for this reduction may offer new molecular targets for colon cancer prevention. We investigated how APC inactivation influences the regulation of FXR expression in colonic mucosal cells. We hypothesized that APC inactivation would epigenetically repress nuclear receptor subfamily 1, group H, member 4 (FXR gene name) expression through increased CpG methylation. Normal proximal colonic mucosa and normal-appearing adjacent colonic mucosa and colon tumors were collected from wild-type C57BL/6J and Apc-deficient (Apc(Min) (/+)) male mice, respectively. The expression of Fxr, ileal bile acid-binding protein (Ibabp), small heterodimer partner (Shp), and cyclooxygenase-2 (Cox-2) were determined by real-time polymerase chain reaction. In both normal and adjacent colonic mucosa and colon tumors, we measured CpG methylation of Fxr in bisulfonated genomic DNA. In vitro, we measured the impact of APC inactivation and deoxycholic acid (DCA) treatment on FXR expression in human colon cancer HCT-116 cells transfected with silencing RNA for APC and HT-29 cells carrying inactivated APC. In Apc(Min) (/+) mice, constitutive CpG methylation of the Fxrα3/4 promoter was linked to reduced (60-90%) baseline Fxr, Ibabp, and Shp and increased Cox-2 expression in apparently normal adjacent mucosa and colon tumors. Apc knockdown in HCT-116 cells increased cellular myelocytomatosis (c-MYC) and lowered (∼50%) FXR expression, which was further reduced (∼80%) by DCA. In human HCT-116 but not HT-29 colon cancer cells, DCA induced FXR expression and lowered CpG methylation of FXR. We conclude that the loss of APC function favors the silencing of FXR expression through CpG hypermethylation in mouse colonic mucosa and human colon cells

  10. The effect of target thickness on x-ray production by FXR [Flash X-Ray Machine

    International Nuclear Information System (INIS)

    Back, N.L.

    1986-01-01

    The electron-photon transport code SANDYL has been used to calculate the x-ray flux for a simplified Flash X-Ray Machine (FXR) bullnose geometry. Four different thicknesses (24.5, 36.75, 49, and 61.25 mils) were used for the tantalum bremsstrahlung target in order to study the effect of target thickness on the FXR output. The calculations were performed for a parallel 17 MeV electron beam, and the resulting angular distributions were then used to compute the forward flux for the more realistic case of a converging beam. Over the range of thicknesses studied, the x-ray energy content per steradian on axis was essentially independent of target thickness. The main reason for this is that, while the total x-ray flux coming out of the target increases with increasing target thickness, the angular width of that flux also increases. The implications for target wheel design are discussed. 3 refs., 7 figs

  11. PARTIAL AGONISTS, FULL AGONISTS, ANTAGONISTS - DILEMMAS OF DEFINITION

    NARCIS (Netherlands)

    HOYER, D; BODDEKE, HWGM

    The absence of selective antagonists makes receptor characterization difficult, and largely dependent on the use of agonists. However, there has been considerable debate as to whether certain drugs acting at G protein-coupled receptors are better described as agonists, partial agonists or

  12. Targeting the transsulfuration-H2S pathway by FXR and GPBAR1 ligands in the treatment of portal hypertension.

    Science.gov (United States)

    Fiorucci, Stefano; Distrutti, Eleonora

    2016-09-01

    Cirrhosis is a end-stage disease of the liver in which fibrogenesis, angiogenesis and distortion of intrahepatic microcirculation lead to increased intrahepatic resistance to portal blood flow, a condition known as portal hypertension. Portal hypertension is maintained by a variety of molecular mechanisms including sinusoidal endothelial cells (LSECs) hyporeactivity, activation of hepatic stellate cells (HSCs), reduction in hepatic endothelial nitric oxide synthase (eNOS) activity along with increased eNOS-derived NO generation in the splanchnic and systemic circulations. A reduction of the expression/function of the two major hydrogen sulfide (H2S)-producing enzymes, cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS), has also been demonstrated. A deficit in the transsulfuration pathway leading to the accumulation of homocysteine might contribute to defective generation of H2S and endothelial hyporeactivity. Bile acids are ligands for nuclear receptors, such as farnesoid X receptor (FXR), and G-protein-coupled receptors (GPCRs), such as the G-protein bile acid receptor 1 (GPBAR1). FXR and GPBAR1 ligands regulate the expression/activity of CSE by both genomic and non-genomic effects and have been proved effective in protecting against endothelial dysfunction observed in rodent models of cirrhosis. GPBAR1, a receptor for secondary bile acids, is selectively expressed by LSECs and its activation increases the expression of CSE and attenuates the production of endotelin-1, a potent vasoconstrictor agent. In vivo GPBAR1 ligand attenuates the imbalance between vasodilatory and vaso-constricting agents, making GPBAR1 a promising target in the treatment of portal hypertension. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Dopaminergic agonists for hepatic encephalopathy

    DEFF Research Database (Denmark)

    Als-Nielsen, B; Gluud, L L; Gluud, C

    2004-01-01

    Hepatic encephalopathy may be associated with an impairment of the dopaminergic neurotransmission. Dopaminergic agonists may therefore have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be associated with an impairment of the dopaminergic neurotransmission. Dopaminergic agonists may therefore have a beneficial effect on patients with hepatic encephalopathy....

  14. PPAR agonists reduce steatosis in oleic acid-overloaded HepaRG cells

    International Nuclear Information System (INIS)

    Rogue, Alexandra; Anthérieu, Sébastien; Vluggens, Aurore; Umbdenstock, Thierry; Claude, Nancy; Moureyre-Spire, Catherine de la; Weaver, Richard J.; Guillouzo, André

    2014-01-01

    Although non-alcoholic fatty liver disease (NAFLD) is currently the most common form of chronic liver disease there is no pharmacological agent approved for its treatment. Since peroxisome proliferator-activated receptors (PPARs) are closely associated with hepatic lipid metabolism, they seem to play important roles in NAFLD. However, the effects of PPAR agonists on steatosis that is a common pathology associated with NAFLD, remain largely controversial. In this study, the effects of various PPAR agonists, i.e. fenofibrate, bezafibrate, troglitazone, rosiglitazone, muraglitazar and tesaglitazar on oleic acid-induced steatotic HepaRG cells were investigated after a single 24-hour or 2-week repeat treatment. Lipid vesicles stained by Oil-Red O and triglycerides accumulation caused by oleic acid overload, were decreased, by up to 50%, while fatty acid oxidation was induced after 2-week co-treatment with PPAR agonists. The greatest effects on reduction of steatosis were obtained with the dual PPARα/γ agonist muraglitazar. Such improvement of steatosis was associated with up-regulation of genes related to fatty acid oxidation activity and down-regulation of many genes involved in lipogenesis. Moreover, modulation of expression of some nuclear receptor genes, such as FXR, LXRα and CAR, which are potent actors in the control of lipogenesis, was observed and might explain repression of de novo lipogenesis. Conclusion: Altogether, our in vitro data on steatotic HepaRG cells treated with PPAR agonists correlated well with clinical investigations, bringing a proof of concept that drug-induced reversal of steatosis in human can be evaluated in in vitro before conducting long-term and costly in vivo studies in animals and patients. - Highlights: • There is no pharmacological agent approved for the treatment of NAFLD. • This study demonstrates that PPAR agonists can reduce fatty acid-induced steatosis. • Some nuclear receptors appear to be potent actors in the control

  15. PPAR agonists reduce steatosis in oleic acid-overloaded HepaRG cells

    Energy Technology Data Exchange (ETDEWEB)

    Rogue, Alexandra [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France); Biologie Servier, Gidy (France); Anthérieu, Sébastien; Vluggens, Aurore [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France); Umbdenstock, Thierry [Technologie Servier, Orléans (France); Claude, Nancy [Institut de Recherches Servier, Courbevoie (France); Moureyre-Spire, Catherine de la; Weaver, Richard J. [Biologie Servier, Gidy (France); Guillouzo, André, E-mail: Andre.Guillouzo@univ-rennes1.fr [Inserm UMR 991, 35043 Rennes Cedex (France); Université de Rennes 1, Faculté des Sciences Pharmaceutiques et Biologiques, 35043 Rennes Cedex (France)

    2014-04-01

    Although non-alcoholic fatty liver disease (NAFLD) is currently the most common form of chronic liver disease there is no pharmacological agent approved for its treatment. Since peroxisome proliferator-activated receptors (PPARs) are closely associated with hepatic lipid metabolism, they seem to play important roles in NAFLD. However, the effects of PPAR agonists on steatosis that is a common pathology associated with NAFLD, remain largely controversial. In this study, the effects of various PPAR agonists, i.e. fenofibrate, bezafibrate, troglitazone, rosiglitazone, muraglitazar and tesaglitazar on oleic acid-induced steatotic HepaRG cells were investigated after a single 24-hour or 2-week repeat treatment. Lipid vesicles stained by Oil-Red O and triglycerides accumulation caused by oleic acid overload, were decreased, by up to 50%, while fatty acid oxidation was induced after 2-week co-treatment with PPAR agonists. The greatest effects on reduction of steatosis were obtained with the dual PPARα/γ agonist muraglitazar. Such improvement of steatosis was associated with up-regulation of genes related to fatty acid oxidation activity and down-regulation of many genes involved in lipogenesis. Moreover, modulation of expression of some nuclear receptor genes, such as FXR, LXRα and CAR, which are potent actors in the control of lipogenesis, was observed and might explain repression of de novo lipogenesis. Conclusion: Altogether, our in vitro data on steatotic HepaRG cells treated with PPAR agonists correlated well with clinical investigations, bringing a proof of concept that drug-induced reversal of steatosis in human can be evaluated in in vitro before conducting long-term and costly in vivo studies in animals and patients. - Highlights: • There is no pharmacological agent approved for the treatment of NAFLD. • This study demonstrates that PPAR agonists can reduce fatty acid-induced steatosis. • Some nuclear receptors appear to be potent actors in the control

  16. Alisol B 23-acetate protects against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes involved in bile acid homeostasis

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Qiang; Chen, Xin-li; Wang, Chang-yuan; Liu, Qi; Sun, Hui-jun; Sun, Peng-yuan; Huo, Xiao-kui; Liu, Zhi-hao; Yao, Ji-hong; Liu, Ke-xin, E-mail: kexinliu@dlmedu.edu.cn

    2015-03-15

    Intrahepatic cholestasis is a clinical syndrome with systemic and intrahepatic accumulation of excessive toxic bile acids that ultimately cause hepatobiliary injury. Appropriate regulation of bile acids in hepatocytes is critically important for protection against liver injury. In the present study, we characterized the protective effect of alisol B 23-acetate (AB23A), a natural triterpenoid, on alpha-naphthylisothiocyanate (ANIT)-induced liver injury and intrahepatic cholestasis in mice and further elucidated the mechanisms in vivo and in vitro. AB23A treatment dose-dependently protected against liver injury induced by ANIT through reducing hepatic uptake and increasing efflux of bile acid via down-regulation of hepatic uptake transporters (Ntcp) and up-regulation of efflux transporter (Bsep, Mrp2 and Mdr2) expression. Furthermore, AB23A reduced bile acid synthesis through repressing Cyp7a1 and Cyp8b1, increased bile acid conjugation through inducing Bal, Baat and bile acid metabolism through an induction in gene expression of Sult2a1. We further demonstrate the involvement of farnesoid X receptor (FXR) in the hepatoprotective effect of AB23A. The changes in transporters and enzymes, as well as ameliorative liver histology in AB23A-treated mice were abrogated by FXR antagonist guggulsterone in vivo. In vitro evidences also directly demonstrated the effect of AB23A on FXR activation in a dose-dependent manner using luciferase reporter assay in HepG2 cells. In conclusion, AB23A produces protective effect against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes. - Highlights: • AB23A has at least three roles in protection against ANIT-induced liver injury. • AB23A decreases Ntcp, and increases Bsep, Mrp2 and Mdr2 expression. • AB23A represses Cyp7a1 and Cyp8b1 through inducing Shp and Fgf15 expression. • AB23A increases bile acid metabolism through inducing Sult2a1 expression. • FXR activation is involved

  17. Alisol B 23-acetate protects against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes involved in bile acid homeostasis

    International Nuclear Information System (INIS)

    Meng, Qiang; Chen, Xin-li; Wang, Chang-yuan; Liu, Qi; Sun, Hui-jun; Sun, Peng-yuan; Huo, Xiao-kui; Liu, Zhi-hao; Yao, Ji-hong; Liu, Ke-xin

    2015-01-01

    Intrahepatic cholestasis is a clinical syndrome with systemic and intrahepatic accumulation of excessive toxic bile acids that ultimately cause hepatobiliary injury. Appropriate regulation of bile acids in hepatocytes is critically important for protection against liver injury. In the present study, we characterized the protective effect of alisol B 23-acetate (AB23A), a natural triterpenoid, on alpha-naphthylisothiocyanate (ANIT)-induced liver injury and intrahepatic cholestasis in mice and further elucidated the mechanisms in vivo and in vitro. AB23A treatment dose-dependently protected against liver injury induced by ANIT through reducing hepatic uptake and increasing efflux of bile acid via down-regulation of hepatic uptake transporters (Ntcp) and up-regulation of efflux transporter (Bsep, Mrp2 and Mdr2) expression. Furthermore, AB23A reduced bile acid synthesis through repressing Cyp7a1 and Cyp8b1, increased bile acid conjugation through inducing Bal, Baat and bile acid metabolism through an induction in gene expression of Sult2a1. We further demonstrate the involvement of farnesoid X receptor (FXR) in the hepatoprotective effect of AB23A. The changes in transporters and enzymes, as well as ameliorative liver histology in AB23A-treated mice were abrogated by FXR antagonist guggulsterone in vivo. In vitro evidences also directly demonstrated the effect of AB23A on FXR activation in a dose-dependent manner using luciferase reporter assay in HepG2 cells. In conclusion, AB23A produces protective effect against ANIT-induced hepatotoxity and cholestasis, due to FXR-mediated regulation of transporters and enzymes. - Highlights: • AB23A has at least three roles in protection against ANIT-induced liver injury. • AB23A decreases Ntcp, and increases Bsep, Mrp2 and Mdr2 expression. • AB23A represses Cyp7a1 and Cyp8b1 through inducing Shp and Fgf15 expression. • AB23A increases bile acid metabolism through inducing Sult2a1 expression. • FXR activation is involved

  18. Flash X-Ray (FXR) Accelerator Optimization Electronic Time-Resolved Measurement of X-Ray Source Size

    International Nuclear Information System (INIS)

    Jacob, J; Ong, M; Wargo, P

    2005-01-01

    Lawrence Livermore National Laboratory (LLNL) is currently investigating various approaches to minimize the x-ray source size on the Flash X-Ray (FXR) linear induction accelerator in order to improve x-ray flux and increase resolution for hydrodynamic radiography experiments. In order to effectively gauge improvements to final x-ray source size, a fast, robust, and accurate system for measuring the spot size is required. Timely feedback on x-ray source size allows new and improved accelerator tunes to be deployed and optimized within the limited run-time constraints of a production facility with a busy experimental schedule; in addition, time-resolved measurement capability allows the investigation of not only the time-averaged source size, but also the evolution of the source size, centroid position, and x-ray dose throughout the 70 ns beam pulse. Combined with time-resolved measurements of electron beam parameters such as emittance, energy, and current, key limiting factors can be identified, modeled, and optimized for the best possible spot size. Roll-bar techniques are a widely used method for x-ray source size measurement, and have been the method of choice at FXR for many years. A thick bar of tungsten or other dense metal with a sharp edge is inserted into the path of the x-ray beam so as to heavily attenuate the lower half of the beam, resulting in a half-light, half-dark image as seen downstream of the roll-bar; by measuring the width of the transition from light to dark across the edge of the roll-bar, the source size can be deduced. For many years, film has been the imaging medium of choice for roll-bar measurements thanks to its high resolution, linear response, and excellent contrast ratio. Film measurements, however, are fairly cumbersome and require considerable setup and analysis time; moreover, with the continuing trend towards all-electronic measurement systems, film is becoming increasingly difficult and expensive to procure. Here, we shall

  19. Hormones and β-Agonists

    NARCIS (Netherlands)

    Ginkel, van L.A.; Bovee, T.F.H.; Blokland, M.H.; Sterk, S.S.; Smits, N.G.E.; Pleadin, Jelka; Vulić, Ana

    2016-01-01

    This chapter provides some updated information on contemporary methods for hormone and β-agonist analyses. It deals with the classical approaches for the effective detection and identification of exogenous hormones. The chapter examines specific problems related to control strategies for natural

  20. Atorvastatin induces bile acid-synthetic enzyme Cyp7a1 by suppressing FXR signaling in both liver and intestine in mice[S

    Science.gov (United States)

    Fu, Zidong Donna; Cui, Julia Yue; Klaassen, Curtis D.

    2014-01-01

    Statins are effective cholesterol-lowering drugs to treat CVDs. Bile acids (BAs), the end products of cholesterol metabolism in the liver, are important nutrient and energy regulators. The present study aims to investigate how statins affect BA homeostasis in the enterohepatic circulation. Male C57BL/6 mice were treated with atorvastatin (100 mg/kg/day po) for 1 week, followed by BA profiling by ultra-performance LC-MS/MS. Atorvastatin decreased BA pool size, mainly due to less BA in the intestine. Surprisingly, atorvastatin did not alter total BAs in the serum or liver. Atorvastatin increased the ratio of 12α-OH/non12α-OH BAs. Atorvastatin increased the mRNAs of the BA-synthetic enzymes cholesterol 7α-hydroxylase (Cyp7a1) (over 10-fold) and cytochrome P450 27a1, the BA uptake transporters Na+/taurocholate cotransporting polypeptide and organic anion transporting polypeptide 1b2, and the efflux transporter multidrug resistance-associated protein 2 in the liver. Noticeably, atorvastatin suppressed the expression of BA nuclear receptor farnesoid X receptor (FXR) target genes, namely small heterodimer partner (liver) and fibroblast growth factor 15 (ileum). Furthermore, atorvastatin increased the mRNAs of the organic cation uptake transporter 1 and cholesterol efflux transporters Abcg5 and Abcg8 in the liver. The increased expression of BA-synthetic enzymes and BA transporters appear to be a compensatory response to maintain BA homeostasis after atorvastatin treatment. The Cyp7a1 induction by atorvastatin appears to be due to suppressed FXR signaling in both the liver and intestine. PMID:25278499

  1. Muscarinic Receptor Agonists and Antagonists

    Directory of Open Access Journals (Sweden)

    David R. Kelly

    2001-02-01

    Full Text Available A comprehensive review of pharmacological and medical aspects of the muscarinic class of acetylcholine agonists and antagonists is presented. The therapeutic benefits of achieving receptor subtype selectivity are outlined and applications in the treatment of Alzheimer’s disease are discussed. A selection of chemical routes are described, which illustrate contemporary methodology for the synthesis of chiral medicinal compounds (asymmetric synthesis, chiral pool, enzymes. Routes to bicyclic intrannular amines and intramolecular Diels-Alder reactions are highlighted.

  2. Emerging GLP-1 receptor agonists

    DEFF Research Database (Denmark)

    Lund, Asger; Knop, Filip K; Vilsbøll, Tina

    2011-01-01

    and liraglutide, as well as the emerging GLP-1R agonists including the long-acting compounds. Expert opinion: An emerging therapeutic trend toward initial or early combination therapy with metformin- and incretin-based therapy is anticipated for patients with type 2 diabetes. GLP-1-based therapy has so far proven...... development may improve the effects of GLP-1 even further with optimized pharmacokinetic profiles resulting in fewer side effects. Meta-analyses have shown promising effects on cardiovascular disease and data from ongoing multicenter trials with cardiovascular endpoints are expected in 2015....

  3. The epileptogenic spectrum of opiate agonists.

    Science.gov (United States)

    Snead, O C; Bearden, L J

    1982-11-01

    The present authors gave mu, delta, kappa, epsilon and sigma opiate receptor agonists intracerebroventricularly to rats both singly and in combination while monitoring the electroencephalogram from cortical and depth electrodes. Dose-response curves were plotted with naloxone against the changes produced by each agonist, and the effect of a number of anticonvulsant drugs on agonist-induced seizures was ascertained. Each opiate agonist produced a different seizure pattern with a different naloxone dose-response curve and anticonvulsant profile. The order of convulsive potency was epsilon greater than delta greater than mu greater than sigma much greater than kappa. Petit mal-like seizure activity was unique to the delta agonist, leucine-enkephalin, while only the mu agonist, morphine produced generalized convulsive seizures. These experiments raise the possibility that opiate systems in the brain may be involved in the pathogenesis of a wide spectrum of seizure disorders.

  4. AGONISTIC BEHAVIOR OF LABORATORY MICE

    Directory of Open Access Journals (Sweden)

    D. Cinghiţă

    2005-01-01

    Full Text Available In this work we study agonistic behavior of laboratory white mice when they are kept in captivity. For all this experimental work we used direct observation of mice, in small lists, because we need a reduced space to emphasize characteristics of agonistic behavior. Relations between members of the same species that live in organized groups are based in most cases on hierarchical structure. Relations between leader and subservient, decided by fighting, involve a thorough observation between individuals. Each member of a group has its own place on the ierarchical scale depending on resultes of fhights – it can be leader or it can be subsurvient, depending on if it wines or looses the fight. Once hierarchical scale made, every animal will adjust its behavior. After analyzing the obtained data we have enough reasons to believe that after fights the winner, usually, is the massive mouse, but it is also very important the sexual ripeness, so the immature male will be beaten. The leader male had a big exploring area and it checks up all territory.The females can be more aggressive, its fights are more brutal, than male fights are, when they fight for supremacy, but in this case fights are not as frequent as in the case of males. Always the superior female, on hierarchical scale, shows males its own statute, so the strongest genes will be perpetuated.

  5. Obeticholic acid, a selective farnesoid X receptor agonist, regulates bile acid homeostasis in sandwich-cultured human hepatocytes.

    Science.gov (United States)

    Zhang, Yuanyuan; Jackson, Jonathan P; St Claire, Robert L; Freeman, Kimberly; Brouwer, Kenneth R; Edwards, Jeffrey E

    2017-08-01

    Farnesoid X receptor (FXR) is a master regulator of bile acid homeostasis through transcriptional regulation of genes involved in bile acid synthesis and cellular membrane transport. Impairment of bile acid efflux due to cholangiopathies results in chronic cholestasis leading to abnormal elevation of intrahepatic and systemic bile acid levels. Obeticholic acid (OCA) is a potent and selective FXR agonist that is 100-fold more potent than the endogenous ligand chenodeoxycholic acid (CDCA). The effects of OCA on genes involved in bile acid homeostasis were investigated using sandwich-cultured human hepatocytes. Gene expression was determined by measuring mRNA levels. OCA dose-dependently increased fibroblast growth factor-19 (FGF-19) and small heterodimer partner (SHP) which, in turn, suppress mRNA levels of cholesterol 7-alpha-hydroxylase (CYP7A1), the rate-limiting enzyme for de novo synthesis of bile acids. Consistent with CYP7A1 suppression, total bile acid content was decreased by OCA (1 μmol/L) to 42.7 ± 20.5% relative to control. In addition to suppressing de novo bile acids synthesis, OCA significantly increased the mRNA levels of transporters involved in bile acid homeostasis. The bile salt excretory pump (BSEP), a canalicular efflux transporter, increased by 6.4 ± 0.8-fold, and the basolateral efflux heterodimer transporters, organic solute transporter α (OST α ) and OST β increased by 6.4 ± 0.2-fold and 42.9 ± 7.9-fold, respectively. The upregulation of BSEP and OST α and OST β, by OCA reduced the intracellular concentrations of d 8 -TCA, a model bile acid, to 39.6 ± 8.9% relative to control. These data demonstrate that OCA does suppress bile acid synthesis and reduce hepatocellular bile acid levels, supporting the use of OCA to treat bile acid-induced toxicity observed in cholestatic diseases. © 2017 Intercept Pharmaceuticals. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and

  6. Beta-agonists and animal welfare

    Science.gov (United States)

    The use of beta-agonists in animal feed is a high profile topic within the U.S. as consumers and activist groups continue to question its safety. The only beta-agonist currently available for use in swine is ractopamine hydrochloride (RAC). This is available as Paylean™ (Elanco Animal Health – FDA a...

  7. Small molecule fluoride toxicity agonists.

    Science.gov (United States)

    Nelson, James W; Plummer, Mark S; Blount, Kenneth F; Ames, Tyler D; Breaker, Ronald R

    2015-04-23

    Fluoride is a ubiquitous anion that inhibits a wide variety of metabolic processes. Here, we report the identification of a series of compounds that enhance fluoride toxicity in Escherichia coli and Streptococcus mutans. These molecules were isolated by using a high-throughput screen (HTS) for compounds that increase intracellular fluoride levels as determined via a fluoride riboswitch reporter fusion construct. A series of derivatives were synthesized to examine structure-activity relationships, leading to the identification of compounds with improved activity. Thus, we demonstrate that small molecule fluoride toxicity agonists can be identified by HTS from existing chemical libraries by exploiting a natural fluoride riboswitch. In addition, our findings suggest that some molecules might be further optimized to function as binary antibacterial agents when combined with fluoride. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Dopamine Agonists and Pathologic Behaviors

    Directory of Open Access Journals (Sweden)

    Brendan J. Kelley

    2012-01-01

    Full Text Available The dopamine agonists ropinirole and pramipexole exhibit highly specific affinity for the cerebral dopamine D3 receptor. Use of these medications in Parkinson’s disease has been complicated by the emergence of pathologic behavioral patterns such as hypersexuality, pathologic gambling, excessive hobbying, and other circumscribed obsessive-compulsive disorders of impulse control in people having no history of such disorders. These behavioral changes typically remit following discontinuation of the medication, further demonstrating a causal relationship. Expression of the D3 receptor is particularly rich within the limbic system, where it plays an important role in modulating the physiologic and emotional experience of novelty, reward, and risk assessment. Converging neuroanatomical, physiological, and behavioral science data suggest the high D3 affinity of these medications as the basis for these behavioral changes. These observations suggest the D3 receptor as a therapeutic target for obsessive-compulsive disorder and substance abuse, and improved understanding of D3 receptor function may aid drug design of future atypical antipsychotics.

  9. Endogenous Receptor Agonists: Resolving Inflammation

    Directory of Open Access Journals (Sweden)

    Gerhard Bannenberg

    2007-01-01

    Full Text Available Controlled resolution or the physiologic resolution of a well-orchestrated inflammatory response at the tissue level is essential to return to homeostasis. A comprehensive understanding of the cellular and molecular events that control the termination of acute inflammation is needed in molecular terms given the widely held view that aberrant inflammation underlies many common diseases. This review focuses on recent advances in the understanding of the role of arachidonic acid and ω-3 polyunsaturated fatty acids (PUFA–derived lipid mediators in regulating the resolution of inflammation. Using a functional lipidomic approach employing LC-MS-MS–based informatics, recent studies, reviewed herein, uncovered new families of local-acting chemical mediators actively biosynthesized during the resolution phase from the essential fatty acids eicosapentaenoic acid (EPA and docosahexaenoic acid (DHA. These new families of local chemical mediators are generated endogenously in exudates collected during the resolution phase, and were coined resolvins and protectins because specific members of these novel chemical families control both the duration and magnitude of inflammation in animal models of complex diseases. Recent advances on the biosynthesis, receptors, and actions of these novel anti-inflammatory and proresolving lipid mediators are reviewed with the aim to bring to attention the important role of specific lipid mediators as endogenous agonists in inflammation resolution.

  10. Negative cooperativity in binding of muscarinic receptor agonists and GDP as a measure of agonist efficacy.

    Science.gov (United States)

    Jakubík, J; Janíčková, H; El-Fakahany, E E; Doležal, V

    2011-03-01

    Conventional determination of agonist efficacy at G-protein coupled receptors is measured by stimulation of guanosine-5'-γ-thiotriphosphate (GTPγS) binding. We analysed the role of guanosine diphosphate (GDP) in the process of activation of the M₂ muscarinic acetylcholine receptor and provide evidence that negative cooperativity between agonist and GDP binding is an alternative measure of agonist efficacy. Filtration and scintillation proximity assays measured equilibrium binding as well as binding kinetics of [³⁵S]GTPγS and [³H]GDP to a mixture of G-proteins as well as individual classes of G-proteins upon binding of structurally different agonists to the M₂ muscarinic acetylcholine receptor. Agonists displayed biphasic competition curves with the antagonist [³H]-N-methylscopolamine. GTPγS (1 µM) changed the competition curves to monophasic with low affinity and 50 µM GDP produced a similar effect. Depletion of membrane-bound GDP increased the proportion of agonist high-affinity sites. Carbachol accelerated the dissociation of [³H]GDP from membranes. The inverse agonist N-methylscopolamine slowed GDP dissociation and GTPγS binding without changing affinity for GDP. Carbachol affected both GDP association with and dissociation from G(i/o) G-proteins but only its dissociation from G(s/olf) G-proteins. These findings suggest the existence of a low-affinity agonist-receptor conformation complexed with GDP-liganded G-protein. Also the negative cooperativity between GDP and agonist binding at the receptor/G-protein complex determines agonist efficacy. GDP binding reveals differences in action of agonists versus inverse agonists as well as differences in activation of G(i/o) versus G(s/olf) G-proteins that are not identified by conventional GTPγS binding. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

  11. Using physics-based pose predictions and free energy perturbation calculations to predict binding poses and relative binding affinities for FXR ligands in the D3R Grand Challenge 2

    Science.gov (United States)

    Athanasiou, Christina; Vasilakaki, Sofia; Dellis, Dimitris; Cournia, Zoe

    2018-01-01

    Computer-aided drug design has become an integral part of drug discovery and development in the pharmaceutical and biotechnology industry, and is nowadays extensively used in the lead identification and lead optimization phases. The drug design data resource (D3R) organizes challenges against blinded experimental data to prospectively test computational methodologies as an opportunity for improved methods and algorithms to emerge. We participated in Grand Challenge 2 to predict the crystallographic poses of 36 Farnesoid X Receptor (FXR)-bound ligands and the relative binding affinities for two designated subsets of 18 and 15 FXR-bound ligands. Here, we present our methodology for pose and affinity predictions and its evaluation after the release of the experimental data. For predicting the crystallographic poses, we used docking and physics-based pose prediction methods guided by the binding poses of native ligands. For FXR ligands with known chemotypes in the PDB, we accurately predicted their binding modes, while for those with unknown chemotypes the predictions were more challenging. Our group ranked #1st (based on the median RMSD) out of 46 groups, which submitted complete entries for the binding pose prediction challenge. For the relative binding affinity prediction challenge, we performed free energy perturbation (FEP) calculations coupled with molecular dynamics (MD) simulations. FEP/MD calculations displayed a high success rate in identifying compounds with better or worse binding affinity than the reference (parent) compound. Our studies suggest that when ligands with chemical precedent are available in the literature, binding pose predictions using docking and physics-based methods are reliable; however, predictions are challenging for ligands with completely unknown chemotypes. We also show that FEP/MD calculations hold predictive value and can nowadays be used in a high throughput mode in a lead optimization project provided that crystal structures of

  12. Small-molecule AT2 receptor agonists

    DEFF Research Database (Denmark)

    Hallberg, Mathias; Sumners, Colin; Steckelings, U Muscha

    2018-01-01

    The discovery of the first selective, small-molecule ATR receptor (AT2R) agonist compound 21 (C21) (8) that is now extensively studied in a large variety of in vitro and in vivo models is described. The sulfonylcarbamate derivative 8, encompassing a phenylthiofen scaffold is the drug-like agonist...... with the highest affinity for the AT2R reported to date (Ki = 0.4 nM). Structure-activity relationships (SAR), regarding different biaryl scaffolds and functional groups attached to these scaffolds and with a particular focus on the impact of various para substituents displacing the methylene imidazole group of 8......, are discussed. Furthermore, the consequences of migration of the methylene imidazole group and presumed structural requirements for ligands that are aimed as AT2R agonists (e.g. 8) or AT2R antagonists (e.g. 9), respectively, are briefly addressed. A summary of the pharmacological actions of C21 (8) is also...

  13. Reciprocity of agonistic support in ravens.

    Science.gov (United States)

    Fraser, Orlaith N; Bugnyar, Thomas

    2012-01-01

    Cooperative behaviour through reciprocation or interchange of valuable services in primates has received considerable attention, especially regarding the timeframe of reciprocation and its ensuing cognitive implications. Much less, however, is known about reciprocity in other animals, particularly birds. We investigated patterns of agonistic support (defined as a third party intervening in an ongoing conflict to attack one of the conflict participants, thus supporting the other) in a group of 13 captive ravens, Corvus corax. We found support for long-term, but not short-term, reciprocation of agonistic support. Ravens were more likely to support individuals who preened them, kin and dominant group members. These results suggest that ravens do not reciprocate on a calculated tit-for-tat basis, but aid individuals from whom reciprocated support would be most useful and those with whom they share a good relationship. Additionally, dyadic levels of agonistic support and consolation (postconflict affiliation from a bystander to the victim) correlated strongly with each other, but we found no evidence to suggest that receiving agonistic support influences the victim's likelihood of receiving support (consolation) after the conflict ends. Our findings are consistent with an emotionally mediated form of reciprocity in ravens and provide additional support for convergent cognitive evolution in birds and mammals.

  14. Gonadotropin releasing hormone agonists: Expanding vistas

    Directory of Open Access Journals (Sweden)

    Navneet Magon

    2011-01-01

    Full Text Available Gonadotropin-releasing hormone (GnRH agonists are derived from native GnRH by amino acid substitution which yields the agonist resistant to degradation and increases its half-life. The hypogonadotropic hypogonadal state produced by GnRH agonists has been often dubbed as "pseudomenopause" or "medical oophorectomy," which are both misnomers. GnRH analogues (GnRH-a work by temporarily "switching off" the ovaries. Ovaries can be "switched off" for the therapy and therapeutic trial of many conditions which include but are not limited to subfertility, endometriosis, adenomyosis, uterine leiomyomas, precocious puberty, premenstrual dysphoric disorder, chronic pelvic pain, or the prevention of menstrual bleeding in special clinical situations. Rapidly expanding vistas of usage of GnRH agonists encompass use in sex reassignment of male to female transsexuals, management of final height in cases of congenital adrenal hyperplasia, and preserving ovarian function in women undergoing cytotoxic chemotherapy. Hypogonadic side effects caused by the use of GnRH agonists can be tackled with use of "add-back" therapy. Goserelin, leuprolide, and nafarelin are commonly used in clinical practice. GnRH-a have provided us a powerful therapeutic approach to the treatment of numerous conditions in reproductive medicine. Recent synthesis of GnRH antagonists with a better tolerability profile may open new avenues for both research and clinical applications. All stakeholders who are partners in women′s healthcare need to join hands to spread awareness so that these drugs can be used to realize their full potential.

  15. Sports doping: Emerging designer and therapeutic B2-agonists

    NARCIS (Netherlands)

    Fragkaki, A.G.; Georgakopoulos, C.; Sterk, S.S.; Nielen, M.W.F.

    2013-01-01

    Beta2-adrenergic agonists, or ß2-agonists, are considered essential bronchodilator drugs in the treatment of bronchial asthma, both as symptom-relievers and, in combination with inhaled corticosteroids, as disease-controllers. The use of ß2-agonists is prohibited in sports by the World Anti-Doping

  16. Modification of kindled amygdaloid seizures by opiate agonists and antagonists.

    Science.gov (United States)

    Albertson, T E; Joy, R M; Stark, L G

    1984-03-01

    The effects of 19 opiate agonists and antagonists on kindled amygdaloid seizures in the rat were studied. The mu agonists tended to reduce the length of elicited afterdischarges and behavioral ranks, while markedly increasing postictal electroencephalogram spikes and behavioral arrest time. These effects were reversed by naloxone. The kappa agonists reduced behavioral rank and variably reduced afterdischarge length with a concomitant lengthening of postictal behavioral arrest time and number of electroencephalogram spikes. The putative sigma agonist, SKF 10,047, reduced afterdischarge durations only at the higher doses tested. The decreases found after the sigma agonists in postictal electroencephalogram spiking and time of behavioral arrest were not reversed by naloxone. Only the lower doses of normeperidine were found to decrease seizure thresholds. The mixed agonist/antagonists (MAA) cyclazocine and cyclorphan markedly increased seizure threshold and reduced afterdischarge duration and behavioral rank. Only the MAA pentazocine tended to increase threshold but not suprathreshold afterdischarge durations. The order of ability to modify the ictal events was MAA (selected) greater than kappa agonists greater than mu agonists greater than sigma agonists. The increase in postictal events (behavior arrest and spikes) was caused most effectively by pretreatment with mu agonist greater than kappa agonist greater than selected MAA greater than sigma agonists.(ABSTRACT TRUNCATED AT 250 WORDS)

  17. Subtype selective kainic acid receptor agonists

    DEFF Research Database (Denmark)

    Bunch, Lennart; Krogsgaard-Larsen, Povl

    2009-01-01

    (S)-Glutamic acid (Glu) is the major excitatory neurotransmitter in the mammalian central nervous system, activating the plethora of glutamate receptors (GluRs). In broad lines, the GluRs are divided into two major classes: the ionotropic Glu receptors (iGluRs) and the metabotropic Glu receptors (m......GluRs). Within the iGluRs, five subtypes (KA1, KA2, iGluR5-7) show high affinity and express full agonist activity upon binding of the naturally occurring amino acid kainic acid (KA). Thus these receptors have been named the KA receptors. This review describes all-to our knowledge-published KA receptor agonists...

  18. Evaluation of partial beta-adrenoceptor agonist activity.

    Science.gov (United States)

    Lipworth, B J; Grove, A

    1997-01-01

    A partial beta-adrenoceptor (beta-AR) agonist will exhibit opposite agonist and antagonist activity depending on the prevailing degree of adrenergic tone or the presence of a beta-AR agonist with higher intrinsic activity. In vivo partial beta-AR agonist activity will be evident at rest with low endogenous adrenergic tone, as for example with chronotropicity (beta 1/beta 2), inotropicity (beta 1) or peripheral vasodilatation and finger tremor (beta 2). beta-AR blocking drugs which have partial agonist activity may exhibit a better therapeutic profile when used for hypertension because of maintained cardiac output without increased systemic vascular resistance, along with an improved lipid profile. In the presence of raised endogenous adrenergic tone such as exercise or an exogenous full agonist, beta-AR subtype antagonist activity will become evident in terms of effects on exercise induced heart rate (beta 1) and potassium (beta 2) responses. Reduction of exercise heart rate will occur to a lesser degree in the case of a beta-adrenoceptor blocker with partial beta 1-AR agonist activity compared with a beta-adrenoceptor blocker devoid of partial agonist activity. This may result in reduced therapeutic efficacy in the treatment of angina on effort when using beta-AR blocking drugs with partial beta 1-AR agonist activity. Effects on exercise hyperkalaemia are determined by the balance between beta 2-AR partial agonist activity and endogenous adrenergic activity. For predominantly beta 2-AR agonist such as salmeterol and salbutamol, potentiation of exercise hyperkalaemia occurs. For predominantly beta 2-AR antagonists such as carteolol, either potentiation or attenuation of exercise hyperkalaemia occurs at low and high doses respectively. beta 2-AR partial agonist activity may also be expressed as antagonism in the presence of an exogenous full agonist, as for example attenuation of fenoterol induced responses by salmeterol. Studies are required to investigate whether

  19. Sulfoximines as potent RORγ inverse agonists.

    Science.gov (United States)

    Ouvry, Gilles; Bihl, Franck; Bouix-Peter, Claire; Christin, Olivier; Defoin-Platel, Claire; Deret, Sophie; Feret, Christophe; Froude, David; Hacini-Rachinel, Feriel; Harris, Craig S; Hervouet, Catherine; Lafitte, Guillaume; Luzy, Anne-Pascale; Musicki, Branislav; Orfila, Danielle; Parnet, Veronique; Pascau, Coralie; Pascau, Jonathan; Pierre, Romain; Raffin, Catherine; Rossio, Patricia; Spiesse, Delphine; Taquet, Nathalie; Thoreau, Etienne; Vatinel, Rodolphe; Vial, Emmanuel; Hennequin, Laurent F

    2018-05-01

    Progress in the identification of suitable RORγ inverse agonists as clinical candidates has been hampered by the high lipophilicity that seems required for high potency on this nuclear receptor. In this context, we decided to focus on the replacement of the hydroxymethyl group found on known modulators to determine if more polarity could be tolerated in this position. SAR of the replacement of this moiety is presented in this article leading to the identification of sulfoximine derivatives as potent modulators with pharmacological activity in the in vivo mouse Imiquimod psoriasis model. Copyright © 2018 Elsevier Ltd. All rights reserved.

  20. GLP-1 agonists for type 2 diabetes

    DEFF Research Database (Denmark)

    Jespersen, Maria J; Knop, Filip K; Christensen, Mikkel

    2013-01-01

    and legal documents in the form of assessment reports from the European Medicines Agency and the United States Food and Drug Administration. EXPERT OPINION: GLP-1-based therapy combines several unique mechanisms of action and have the potential to gain widespread use in the fight against diabetes......Within recent years, glucagon-like peptide 1 receptor agonists (GLP-1-RA) have emerged as a new treatment option for type 2 diabetes. The GLP-1-RA are administered subcutaneously and differ substantially in pharmacokinetic profiles. AREAS COVERED: This review describes the pharmacokinetics...

  1. Sports doping: emerging designer and therapeutic β2-agonists.

    Science.gov (United States)

    Fragkaki, A G; Georgakopoulos, C; Sterk, S; Nielen, M W F

    2013-10-21

    Beta2-adrenergic agonists, or β2-agonists, are considered essential bronchodilator drugs in the treatment of bronchial asthma, both as symptom-relievers and, in combination with inhaled corticosteroids, as disease-controllers. The use of β2-agonists is prohibited in sports by the World Anti-Doping Agency (WADA) due to claimed anabolic effects, and also, is prohibited as growth promoters in cattle fattening in the European Union. This paper reviews the last seven-year (2006-2012) literature concerning the development of novel β2-agonists molecules either by modifying the molecule of known β2-agonists or by introducing moieties producing indole-, adamantyl- or phenyl urea derivatives. New emerging β2-agonists molecules for future therapeutic use are also presented, intending to emphasize their potential use for doping purposes or as growth promoters in the near future. © 2013.

  2. The farnesoid X receptor agonist obeticholic acid upregulates biliary excretion of asymmetric dimethylarginine via MATE-1 during hepatic ischemia/reperfusion injury

    Science.gov (United States)

    Berardo, Clarissa; Siciliano, Veronica; Rizzo, Vittoria; Adorini, Luciano; Richelmi, Plinio

    2018-01-01

    Background We previously showed that increased asymmetric dimethylarginine (ADMA) biliary excretion occurs during hepatic ischemia/reperfusion (I/R), prompting us to study the effects of the farnesoid X receptor (FXR) agonist obeticholic acid (OCA) on bile, serum and tissue levels of ADMA after I/R. Material and methods Male Wistar rats were orally administered 10mg/kg/day of OCA or vehicle for 5 days and were subjected to 60 min partial hepatic ischemia or sham-operated. After a 60 min reperfusion, serum, tissue and bile ADMA levels, liver mRNA and protein expression of ADMA transporters (CAT-1, CAT-2A, CAT-2B, OCT-1, MATE-1), and enzymes involved in ADMA synthesis (protein-arginine-N-methyltransferase-1, PRMT-1) and metabolism (dimethylarginine-dimethylaminohydrolase-1, DDAH-1) were measured. Results OCA administration induced a further increase in biliary ADMA levels both in sham and I/R groups, with no significant changes in hepatic ADMA content. A reduction in CAT-1, CAT-2A or CAT-2B transcripts was found in OCA-treated sham-operated rats compared with vehicle. Conversely, OCA administration did not change CAT-1, CAT-2A or CAT-2B expression, already reduced by I/R. However, a marked decrease in OCT-1 and increase in MATE-1 expression was observed. A similar trend occurred with protein expression. Conclusion The reduced mRNA expression of hepatic CAT transporters suggests that the increase in serum ADMA levels is probably due to decreased liver uptake of ADMA from the systemic circulation. Conversely, the mechanism involved in further increasing biliary ADMA levels in sham and I/R groups treated with OCA appears to be MATE-1-dependent. PMID:29346429

  3. Principles of agonist recognition in Cys-loop receptors

    DEFF Research Database (Denmark)

    Lynagh, Timothy Peter; Pless, Stephan Alexander

    2014-01-01

    , functional studies, and X-ray crystallography experiments identified the extracellular interface of adjacent subunits as the principal site of agonist binding. The question of how subtle differences at and around agonist-binding sites of different Cys-loop receptors can accommodate transmitters as chemically...

  4. Combining GLP-1 receptor agonists with insulin

    DEFF Research Database (Denmark)

    Holst, Jens Juul; Vilsbøll, T

    2013-01-01

    Due to the increasing prevalence of type 2 diabetes mellitus (T2DM), the emergent trend towards diagnosis in younger patients and the progressive nature of this disease, many more patients than before now require insulin to maintain glycaemic control. However, there is a degree of inertia among...... physicians and patients regarding the initiation and intensification of insulin therapy, in part due to concerns about the associated weight gain and increased risk of hypoglycaemia. Glucagon-like peptide-1 receptor agonists (GLP-1RAs) increase insulin release and suppress glucagon secretion in a glucose......, compared with insulin, the antihyperglycaemic efficacy of GLP-1RAs is limited. The combination of a GLP-1RA and insulin might thus be highly effective for optimal glucose control, ameliorating the adverse effects typically associated with insulin. Data from clinical studies support the therapeutic...

  5. Dopamine agonist withdrawal syndrome: implications for patient care.

    Science.gov (United States)

    Nirenberg, Melissa J

    2013-08-01

    Dopamine agonists are effective treatments for a variety of indications, including Parkinson's disease and restless legs syndrome, but may have serious side effects, such as orthostatic hypotension, hallucinations, and impulse control disorders (including pathological gambling, compulsive eating, compulsive shopping/buying, and hypersexuality). The most effective way to alleviate these side effects is to taper or discontinue dopamine agonist therapy. A subset of patients who taper a dopamine agonist, however, develop dopamine agonist withdrawal syndrome (DAWS), which has been defined as a severe, stereotyped cluster of physical and psychological symptoms that correlate with dopamine agonist withdrawal in a dose-dependent manner, cause clinically significant distress or social/occupational dysfunction, are refractory to levodopa and other dopaminergic medications, and cannot be accounted for by other clinical factors. The symptoms of DAWS include anxiety, panic attacks, dysphoria, depression, agitation, irritability, suicidal ideation, fatigue, orthostatic hypotension, nausea, vomiting, diaphoresis, generalized pain, and drug cravings. The severity and prognosis of DAWS is highly variable. While some patients have transient symptoms and make a full recovery, others have a protracted withdrawal syndrome lasting for months to years, and therefore may be unwilling or unable to discontinue DA therapy. Impulse control disorders appear to be a major risk factor for DAWS, and are present in virtually all affected patients. Thus, patients who are unable to discontinue dopamine agonist therapy may experience chronic impulse control disorders. At the current time, there are no known effective treatments for DAWS. For this reason, providers are urged to use dopamine agonists judiciously, warn patients about the risks of DAWS prior to the initiation of dopamine agonist therapy, and follow patients closely for withdrawal symptoms during dopamine agonist taper.

  6. Activation of farnesoid X receptor attenuates hepatic injury in a murine model of alcoholic liver disease

    International Nuclear Information System (INIS)

    Wu, Weibin; Zhu, Bo; Peng, Xiaomin; Zhou, Meiling; Jia, Dongwei; Gu, Jianxin

    2014-01-01

    Highlights: •FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. •Activation of FXR attenuated alcohol-induced liver injury and steatosis. •Activation of FXR attenuated cholestasis and oxidative stress in mouse liver. -- Abstract: Alcoholic liver disease (ALD) is a common cause of advanced liver disease, and considered as a major risk factor of morbidity and mortality worldwide. Hepatic cholestasis is a pathophysiological feature observed in all stages of ALD. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily, and plays an essential role in the regulation of bile acid, lipid and glucose homeostasis. However, the role of FXR in the pathogenesis and progression of ALD remains largely unknown. Mice were fed Lieber-DeCarli ethanol diet or an isocaloric control diet. We used a specific agonist of FXR WAY-362450 to study the effect of pharmacological activation of FXR in alcoholic liver disease. In this study, we demonstrated that FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. Activation of FXR by specific agonist WAY-362450 protected mice from the development of ALD. We also found that WAY-362450 treatment rescued FXR activity, suppressed ethanol-induced Cyp2e1 up-regulation and attenuated oxidative stress in liver. Our results highlight a key role of FXR in the modulation of ALD development, and propose specific FXR agonists for the treatment of ALD patients

  7. Activation of farnesoid X receptor attenuates hepatic injury in a murine model of alcoholic liver disease

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Weibin [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Institutes of Biomedical Science, Fudan University, Shanghai 200032 (China); Zhu, Bo; Peng, Xiaomin [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Zhou, Meiling, E-mail: meilingzhou2012@gmail.com [Department of Radiology, Zhongshan Hospital of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032 (China); Jia, Dongwei, E-mail: jiadongwei@fudan.edu.cn [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Gu, Jianxin [Department of Biochemistry and Molecular Biology, Shanghai Medical College, Fudan University, Shanghai 200032 (China); Institutes of Biomedical Science, Fudan University, Shanghai 200032 (China)

    2014-01-03

    Highlights: •FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. •Activation of FXR attenuated alcohol-induced liver injury and steatosis. •Activation of FXR attenuated cholestasis and oxidative stress in mouse liver. -- Abstract: Alcoholic liver disease (ALD) is a common cause of advanced liver disease, and considered as a major risk factor of morbidity and mortality worldwide. Hepatic cholestasis is a pathophysiological feature observed in all stages of ALD. The farnesoid X receptor (FXR) is a member of the nuclear hormone receptor superfamily, and plays an essential role in the regulation of bile acid, lipid and glucose homeostasis. However, the role of FXR in the pathogenesis and progression of ALD remains largely unknown. Mice were fed Lieber-DeCarli ethanol diet or an isocaloric control diet. We used a specific agonist of FXR WAY-362450 to study the effect of pharmacological activation of FXR in alcoholic liver disease. In this study, we demonstrated that FXR activity was impaired by chronic ethanol ingestion in a murine model of ALD. Activation of FXR by specific agonist WAY-362450 protected mice from the development of ALD. We also found that WAY-362450 treatment rescued FXR activity, suppressed ethanol-induced Cyp2e1 up-regulation and attenuated oxidative stress in liver. Our results highlight a key role of FXR in the modulation of ALD development, and propose specific FXR agonists for the treatment of ALD patients.

  8. Nicotine receptor partial agonists for smoking cessation

    Directory of Open Access Journals (Sweden)

    Kate Cahill

    Full Text Available BACKGROUND: Nicotine receptor partial agonists may help people to stop smoking by a combination of maintaining moderate levels of dopamine to counteract withdrawal symptoms (acting as an agonist and reducing smoking satisfaction (acting as an antagonist. OBJECTIVES: The primary objective of this review is to assess the efficacy and tolerability of nicotine receptor partial agonists, including cytisine, dianicline and varenicline for smoking cessation. SEARCH METHODS: We searched the Cochrane Tobacco Addiction Group's specialised register for trials, using the terms ('cytisine' or 'Tabex' or 'dianicline' or 'varenicline' or 'nicotine receptor partial agonist' in the title or abstract, or as keywords. The register is compiled from searches of MEDLINE, EMBASE, PsycINFO and Web of Science using MeSH terms and free text to identify controlled trials of interventions for smoking cessation and prevention. We contacted authors of trial reports for additional information where necessary. The latest update of the specialized register was in December 2011. We also searched online clinical trials registers. SELECTION CRITERIA: We included randomized controlled trials which compared the treatment drug with placebo. We also included comparisons with bupropion and nicotine patches where available. We excluded trials which did not report a minimum follow-up period of six months from start of treatment. DATA COLLECTION AND ANALYSIS: We extracted data on the type of participants, the dose and duration of treatment, the outcome measures, the randomization procedure, concealment of allocation, and completeness of follow-up. The main outcome measured was abstinence from smoking at longest follow-up. We used the most rigorous definition of abstinence, and preferred biochemically validated rates where they were reported. Where appropriate we pooled risk ratios (RRs, using the Mantel-Haenszel fixed-effect model. MAIN RESULTS: Two recent cytisine trials (937 people

  9. Nicotine receptor partial agonists for smoking cessation.

    Science.gov (United States)

    Cahill, Kate; Stead, Lindsay F; Lancaster, Tim

    2012-04-18

    Nicotine receptor partial agonists may help people to stop smoking by a combination of maintaining moderate levels of dopamine to counteract withdrawal symptoms (acting as an agonist) and reducing smoking satisfaction (acting as an antagonist). The primary objective of this review is to assess the efficacy and tolerability of nicotine receptor partial agonists, including cytisine, dianicline and varenicline for smoking cessation. We searched the Cochrane Tobacco Addiction Group's specialised register for trials, using the terms ('cytisine' or 'Tabex' or 'dianicline' or 'varenicline' or 'nicotine receptor partial agonist') in the title or abstract, or as keywords. The register is compiled from searches of MEDLINE, EMBASE, PsycINFO and Web of Science using MeSH terms and free text to identify controlled trials of interventions for smoking cessation and prevention. We contacted authors of trial reports for additional information where necessary. The latest update of the specialised register was in December 2011. We also searched online clinical trials registers. We included randomized controlled trials which compared the treatment drug with placebo. We also included comparisons with bupropion and nicotine patches where available. We excluded trials which did not report a minimum follow-up period of six months from start of treatment. We extracted data on the type of participants, the dose and duration of treatment, the outcome measures, the randomization procedure, concealment of allocation, and completeness of follow-up.The main outcome measured was abstinence from smoking at longest follow-up. We used the most rigorous definition of abstinence, and preferred biochemically validated rates where they were reported. Where appropriate we pooled risk ratios (RRs), using the Mantel-Haenszel fixed-effect model. Two recent cytisine trials (937 people) found that more participants taking cytisine stopped smoking compared with placebo at longest follow-up, with a pooled RR of

  10. Alveolar type II epithelial cell dysfunction in rat experimental hepatopulmonary syndrome (HPS.

    Directory of Open Access Journals (Sweden)

    Wenli Yang

    Full Text Available The hepatopulmonary syndrome (HPS develops when pulmonary vasodilatation leads to abnormal gas exchange. However, in human HPS, restrictive ventilatory defects are also observed supporting that the alveolar epithelial compartment may also be affected. Alveolar type II epithelial cells (AT2 play a critical role in maintaining the alveolar compartment by producing four surfactant proteins (SPs, SP-A, SP-B, SP-C and SP-D which also facilitate alveolar repair following injury. However, no studies have evaluated the alveolar epithelial compartment in experimental HPS. In this study, we evaluated the alveolar epithelial compartment and particularly AT2 cells in experimental HPS induced by common bile duct ligation (CBDL. We found a significant reduction in pulmonary SP production associated with increased apoptosis in AT2 cells after CBDL relative to controls. Lung morphology showed decreased mean alveolar chord length and lung volumes in CBDL animals that were not seen in control models supporting a selective reduction of alveolar airspace. Furthermore, we found that administration of TNF-α, the bile acid, chenodeoxycholic acid, and FXR nuclear receptor activation (GW4064 induced apoptosis and impaired SP-B and SP-C production in alveolar epithelial cells in vitro. These results imply that AT2 cell dysfunction occurs in experimental HPS and is associated with alterations in the alveolar epithelial compartment. Our findings support a novel contributing mechanism in experimental HPS that may be relevant to humans and a potential therapeutic target.

  11. Partial agonist therapy in schizophrenia: relevance to diminished criminal responsibility.

    Science.gov (United States)

    Gavaudan, Gilles; Magalon, David; Cohen, Julien; Lançon, Christophe; Léonetti, Georges; Pélissier-Alicot, Anne-Laure

    2010-11-01

    Pathological gambling (PG), classified in the DSM-IV among impulse control disorders, is defined as inappropriate, persistent gaming for money with serious personal, family, and social consequences. Offenses are frequently committed to obtain money for gambling. Pathological gambling, a planned and structured behavioral disorder, has often been described as a complication of dopamine agonist treatment in patients with Parkinson's disease. It has never been described in patients with schizophrenia receiving dopamine agonists. We present two patients with schizophrenia, previously treated with antipsychotic drugs without any suggestion of PG, who a short time after starting aripiprazole, a dopamine partial agonist, developed PG and criminal behavior, which totally resolved when aripiprazole was discontinued. Based on recent advances in research on PG and adverse drug reactions to dopamine agonists in Parkinson's disease, we postulate a link between aripiprazole and PG in both our patients with schizophrenia and raise the question of criminal responsibility. © 2010 American Academy of Forensic Sciences.

  12. MELATONIN DAN MELATONIN RECEPTOR AGONIST SEBAGAI PENANGANAN INSOMNIA PRIMER KRONIS

    Directory of Open Access Journals (Sweden)

    Ni Luh Putu Ayu Maha Iswari

    2013-04-01

    Full Text Available Melatonin is a hormone that has an important role in the mechanism of sleep. Hypnotic effects of melatonin and melatonin receptor agonist are mediated via MT1 and MT2 receptors, especially in circadian rhythm pacemaker, suprachiasmatic nucleus, which is worked on the hypothalamic sleep switch. This mechanism is quite different with the GABAergic drugs such as benzodiazepine. Agonist melatonin triggers the initiation of sleep and normalize circadian rhythms so that makes it easier to maintain sleep. The main disadvantage of melatonin in helping sleep maintenance on primary insomnia is that the half life is very short. The solution to this problem is the use of prolonged-release melatonin and melatonin receptor agonist agents such as ramelteon. Melatoninergic agonist does not cause withdrawal effects, dependence, as well as cognitive and psychomotor disorders as often happens on the use of benzodiazepine.  

  13. Trial Watch: Toll-like receptor agonists for cancer therapy.

    Science.gov (United States)

    Vacchelli, Erika; Eggermont, Alexander; Sautès-Fridman, Catherine; Galon, Jérôme; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2013-08-01

    Toll-like receptors (TLRs) have long been known for their ability to initiate innate immune responses upon exposure to conserved microbial components such as lipopolysaccharide (LPS) and double-stranded RNA. More recently, this family of pattern recognition receptors has been attributed a critical role in the elicitation of anticancer immune responses, raising interest in the development of immunochemotherapeutic regimens based on natural or synthetic TLR agonists. In spite of such an intense wave of preclinical and clinical investigation, only three TLR agonists are currently licensed by FDA for use in cancer patients: bacillus Calmette-Guérin (BCG), an attenuated strain of Mycobacterium bovis that operates as a mixed TLR2/TLR4 agonist; monophosphoryl lipid A (MPL), a derivative of Salmonella minnesota that functions as a potent agonist of TLR4; and imiquimod, a synthetic imidazoquinoline that activates TLR7. One year ago, in the August and September issues of OncoImmunology , we described the main biological features of TLRs and discussed the progress of clinical studies evaluating the safety and therapeutic potential of TLR agonists in cancer patients. Here, we summarize the latest developments in this exciting area of research, focusing on preclinical studies that have been published during the last 13 mo and clinical trials launched in the same period to investigate the antineoplastic activity of TLR agonists.

  14. Should We Use PPAR Agonists to Reduce Cardiovascular Risk?

    Directory of Open Access Journals (Sweden)

    Jennifer G. Robinson

    2008-01-01

    Full Text Available Trials of peroxisome proliferator-activated receptor (PPAR agonists have shown mixed results for cardiovascular prevention. Fibrates are PPAR- agonists that act primarily to improve dyslipidemia. Based on low- and high-density lipoprotein cholesterol (LDL and HDL effects, gemfibrozil may be of greater cardiovascular benefit than expected, fenofibrate performed about as expected, and bezafibrate performed worse than expected. Increases in both cardiovascular and noncardiovascular serious adverse events have been observed with some fibrates. Thiazolidinediones (TZDs are PPAR- agonists used to improve impaired glucose metabolism but also influence lipids. Pioglitazone reduces atherosclerotic events in diabetic subjects, but has no net cardiovascular benefit due to increased congestive heart failure risk. Rosiglitazone may increase the risk of atherosclerotic events, and has a net harmful effect on the cardiovascular system when congestive heart failure is included. The primary benefit of TZDs appears to be the prevention of diabetic microvascular complications. Dual PPAR-/ agonists have had unacceptable adverse effects but more selective agents are in development. PPAR- and pan-agonists are also in development. It will be imperative to prove that future PPAR agonists not only prevent atherosclerotic events but also result in a net reduction on total cardiovascular events without significant noncardiovascular adverse effects with long-term use.

  15. Overlapping binding site for the endogenous agonist, small-molecule agonists, and ago-allosteric modulators on the ghrelin receptor

    DEFF Research Database (Denmark)

    Holst, Birgitte; Frimurer, Thomas M; Mokrosinski, Jacek

    2008-01-01

    A library of robust ghrelin receptor mutants with single substitutions at 22 positions in the main ligand-binding pocket was employed to map binding sites for six different agonists: two peptides (the 28-amino-acid octanoylated endogenous ligand ghrelin and the hexapeptide growth hormone......, and PheVI:23 on the opposing face of transmembrane domain (TM) VI. Each of the agonists was also affected selectively by specific mutations. The mutational map of the ability of L-692,429 and GHRP-6 to act as allosteric modulators by increasing ghrelin's maximal efficacy overlapped with the common....... It is concluded that although each of the ligands in addition exploits other parts of the receptor, a large, common binding site for both small-molecule agonists--including ago-allosteric modulators--and the endogenous agonist is found on the opposing faces of TM-III and -VI of the ghrelin receptor....

  16. Exploring the binding energy profiles of full agonists, partial agonists, and antagonists of the α7 nicotinic acetylcholine receptor.

    Science.gov (United States)

    Tabassum, Nargis; Ma, Qianyun; Wu, Guanzhao; Jiang, Tao; Yu, Rilei

    2017-09-01

    Nicotinic acetylcholine receptors (nAChRs) belong to the Cys-loop receptor family and are important drug targets for the treatment of neurological diseases. However, the precise determinants of the binding efficacies of ligands for these receptors are unclear. Therefore, in this study, the binding energy profiles of various ligands (full agonists, partial agonists, and antagonists) were quantified by docking those ligands with structural ensembles of the α7 nAChR exhibiting different degrees of C-loop closure. This approximate treatment of interactions suggested that full agonists, partial agonists, and antagonists of the α7 nAChR possess distinctive binding energy profiles. Results from docking revealed that ligand binding efficacy may be related to the capacity of the ligand to stabilize conformational states with a closed C loop.

  17. The evolution of farnesoid X, vitamin D, and pregnane X receptors: insights from the green-spotted pufferfish (Tetraodon nigriviridis and other non-mammalian species

    Directory of Open Access Journals (Sweden)

    Kullman Seth W

    2011-02-01

    Full Text Available Abstract Background The farnesoid X receptor (FXR, pregnane X receptor (PXR, and vitamin D receptor (VDR are three closely related nuclear hormone receptors in the NR1H and 1I subfamilies that share the property of being activated by bile salts. Bile salts vary significantly in structure across vertebrate species, suggesting that receptors binding these molecules may show adaptive evolutionary changes in response. We have previously shown that FXRs from the sea lamprey (Petromyzon marinus and zebrafish (Danio rerio are activated by planar bile alcohols found in these two species. In this report, we characterize FXR, PXR, and VDR from the green-spotted pufferfish (Tetraodon nigriviridis, an actinopterygian fish that unlike the zebrafish has a bile salt profile similar to humans. We utilize homology modelling, docking, and pharmacophore studies to understand the structural features of the Tetraodon receptors. Results Tetraodon FXR has a ligand selectivity profile very similar to human FXR, with strong activation by the synthetic ligand GW4064 and by the primary bile acid chenodeoxycholic acid. Homology modelling and docking studies suggest a ligand-binding pocket architecture more similar to human and rat FXRs than to lamprey or zebrafish FXRs. Tetraodon PXR was activated by a variety of bile acids and steroids, although not by the larger synthetic ligands that activate human PXR such as rifampicin. Homology modelling predicts a larger ligand-binding cavity than zebrafish PXR. We also demonstrate that VDRs from the pufferfish and Japanese medaka were activated by small secondary bile acids such as lithocholic acid, whereas the African clawed frog VDR was not. Conclusions Our studies provide further evidence of the relationship between both FXR, PXR, and VDR ligand selectivity and cross-species variation in bile salt profiles. Zebrafish and green-spotted pufferfish provide a clear contrast in having markedly different primary bile salt profiles

  18. Unique interaction pattern for a functionally biased ghrelin receptor agonist

    DEFF Research Database (Denmark)

    Sivertsen, Bjørn Behrens; Lang, Manja; Frimurer, Thomas M.

    2011-01-01

    Based on the conformationally constrained D-Trp-Phe-D-Trp (wFw) core of the prototype inverse agonist [D-Arg(1),D-Phe(5),D-Trp(7,9),Leu(11)]substance P, a series of novel, small, peptide-mimetic agonists for the ghrelin receptor were generated. By using various simple, ring-constrained spacers...... connecting the D-Trp-Phe-D-Trp motif with the important C-terminal carboxyamide group, 40 nm agonism potency was obtained and also in one case (wFw-Isn-NH(2), where Isn is isonipecotic acid) ~80% efficacy. However, in contrast to all previously reported ghrelin receptor agonists, the piperidine-constrained w......Fw-Isn-NH(2) was found to be a functionally biased agonist. Thus, wFw-Isn-NH(2) mediated potent and efficacious signaling through the Ga(q) and ERK1/2 signaling pathways, but in contrast to all previous ghrelin receptor agonists it did not signal through the serum response element, conceivably the Ga(12...

  19. Modification of opiate agonist binding by pertussis toxin

    Energy Technology Data Exchange (ETDEWEB)

    Abood, M.E.; Lee, N.M.; Loh, H.H.

    1986-03-05

    Opiate agonist binding is decreased by GTP, suggesting the possible involvement of GTP binding proteins in regulation of opiate receptor binding. This possibility was addressed by asking whether pertussis toxin treatment, which results in ADP-ribosylation and modification of G proteins, would alter opiate agonist binding. The striatum was chosen for the initial brain area to be studied, since regulation of opiate action in this area had been shown to be modified by pertussis toxin. Treatment of striatal membranes with pertussis toxin results in up to a 55% decrease in /sup 3/(H)-DADLE binding as compared with membranes treated identically without toxin. This corresponds to a near complete ADP-ribosylation of both G proteins in the striatal membrane. The decrease in agonist binding appears to be due to an altered affinity of the receptor for agonist as opposed to a decrease in the number of sites. This effect of pertussis toxin on opiate agonist binding demonstrates the actual involvement of G proteins in regulation of opiate receptor binding.

  20. Ecdysone Agonist: New Insecticides with Novel Mode of Action

    Directory of Open Access Journals (Sweden)

    Y. Andi Trisyono

    2002-12-01

    Full Text Available Development of insect resistance to insecticide has been the major driving force for the development of new insecticides. Awareness and demand from public for more environmentally friendly insecticides have contributed in shifting the trend from using broad spectrum to selective insecticides. As a result, scientists have looked for new target sites beyond the nervous system. Insect growth regulators (IGRs are more selective insecticides than conventional insecticides, and ecdysone agonists are the newest IGRs being commercialized, e.g. tebufenozide, methoxyfenozide, and halofenozide. Ecdysone agonists bind to the ecdysteroid receptors, and they act similarly to the molting hormone 20-hydroxyecdysone. The binding provides larvae or nymphs with a signal to enter a premature and lethal molting cycle. In addition, the ecdysone agonists cause a reduction in the number of eggs laid by female insects. The ecdysone agonists are being developed as selective biorational insecticides. Tebufenozide and methoxyfenozide are used to control lepidopteran insect pests, whereas halofenozide is being used to control coleopteran insect pests. Their selectivity is due to differences in the binding affinity between these compounds to the receptors in insects from different orders. The selectivity of these compounds makes them candidates to be used in combinations with other control strategies to develop integrated pest management programs in agricultural ecosystems. Key words: new insecticides, selectivity, ecdysone agonists

  1. Modification of opiate agonist binding by pertussis toxin

    International Nuclear Information System (INIS)

    Abood, M.E.; Lee, N.M.; Loh, H.H.

    1986-01-01

    Opiate agonist binding is decreased by GTP, suggesting the possible involvement of GTP binding proteins in regulation of opiate receptor binding. This possibility was addressed by asking whether pertussis toxin treatment, which results in ADP-ribosylation and modification of G proteins, would alter opiate agonist binding. The striatum was chosen for the initial brain area to be studied, since regulation of opiate action in this area had been shown to be modified by pertussis toxin. Treatment of striatal membranes with pertussis toxin results in up to a 55% decrease in 3 (H)-DADLE binding as compared with membranes treated identically without toxin. This corresponds to a near complete ADP-ribosylation of both G proteins in the striatal membrane. The decrease in agonist binding appears to be due to an altered affinity of the receptor for agonist as opposed to a decrease in the number of sites. This effect of pertussis toxin on opiate agonist binding demonstrates the actual involvement of G proteins in regulation of opiate receptor binding

  2. Activation of farnesoid X receptor induces RECK expression in mouse liver

    International Nuclear Information System (INIS)

    Peng, Xiaomin; Wu, Weibin; Zhu, Bo; Sun, Zhichao; Ji, Lingling; Ruan, Yuanyuan; Zhou, Meiling; Zhou, Lei; Gu, Jianxin

    2014-01-01

    Highlights: •RECK is a novel transcriptional target gene of FXR in mouse liver. •The FXR response element is located within the intron 1 of RECK gene. •FXR agonist reverses the down-regulation of RECK in the liver in mouse NASH model. -- Abstract: Farnesoid X receptor (FXR) belongs to the ligand-activated nuclear receptor superfamily, and functions as a transcription factor regulating the transcription of numerous genes involved in bile acid homeostasis, lipoprotein and glucose metabolism. In the present study, we identified RECK, a membrane-anchored inhibitor of matrix metalloproteinases, as a novel target gene of FXR in mouse liver. We found that FXR agonist substantially augmented hepatic RECK mRNA and protein expression in vivo and in vitro. FXR regulated the transcription of RECK through directly binding to FXR response element located within intron 1 of the mouse RECK gene. Moreover, FXR agonist reversed the down-regulation of RECK in the livers from mice fed a methionine and choline deficient diet. In summary, our data suggest that RECK is a novel transcriptional target of FXR in mouse liver, and provide clues to better understanding the function of FXR in liver

  3. Activation of farnesoid X receptor induces RECK expression in mouse liver

    Energy Technology Data Exchange (ETDEWEB)

    Peng, Xiaomin [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Wu, Weibin [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Institutes of Biomedical Sciences, Fudan University, Shanghai 200032 (China); Zhu, Bo; Sun, Zhichao; Ji, Lingling; Ruan, Yuanyuan [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Zhou, Meiling, E-mail: meilingzhou2012@gmail.com [Department of Radiology, Zhongshan Hospital of Fudan University and Shanghai Institute of Medical Imaging, Shanghai 200032 (China); Zhou, Lei, E-mail: yhchloech@gmail.com [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Gu, Jianxin [Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Fudan University, Shanghai 200032 (China); Institutes of Biomedical Sciences, Fudan University, Shanghai 200032 (China)

    2014-01-03

    Highlights: •RECK is a novel transcriptional target gene of FXR in mouse liver. •The FXR response element is located within the intron 1 of RECK gene. •FXR agonist reverses the down-regulation of RECK in the liver in mouse NASH model. -- Abstract: Farnesoid X receptor (FXR) belongs to the ligand-activated nuclear receptor superfamily, and functions as a transcription factor regulating the transcription of numerous genes involved in bile acid homeostasis, lipoprotein and glucose metabolism. In the present study, we identified RECK, a membrane-anchored inhibitor of matrix metalloproteinases, as a novel target gene of FXR in mouse liver. We found that FXR agonist substantially augmented hepatic RECK mRNA and protein expression in vivo and in vitro. FXR regulated the transcription of RECK through directly binding to FXR response element located within intron 1 of the mouse RECK gene. Moreover, FXR agonist reversed the down-regulation of RECK in the livers from mice fed a methionine and choline deficient diet. In summary, our data suggest that RECK is a novel transcriptional target of FXR in mouse liver, and provide clues to better understanding the function of FXR in liver.

  4. Principles of agonist recognition in Cys-loop receptors

    Directory of Open Access Journals (Sweden)

    Timothy eLynagh

    2014-04-01

    Full Text Available Cys-loop receptors are ligand-gated ion channels that are activated by a structurally diverse array of neurotransmitters, including acetylcholine, serotonin, glycine and GABA. After the term chemoreceptor emerged over 100 years ago, there was some wait until affinity labeling, molecular cloning, functional studies and X-ray crystallography experiments identified the extracellular interface of adjacent subunits as the principal site of agonist binding. The question of how subtle differences at and around agonist-binding sites of different Cys-loop receptors can accommodate transmitters as chemically diverse as glycine and serotonin has been subject to intense research over the last three decades. This review outlines the functional diversity and current structural understanding of agonist-binding sites, including those of invertebrate Cys-loop receptors. Together, this provides a framework to understand the atomic determinants involved in how these valuable therapeutic targets recognize and bind their ligands.

  5. In silico discovery of novel Retinoic Acid Receptor agonist structures

    Directory of Open Access Journals (Sweden)

    Samuels Herbert H

    2001-06-01

    Full Text Available Abstract Background Several Retinoic Acid Receptors (RAR agonists have therapeutic activity against a variety of cancer types; however, unacceptable toxicity profiles have hindered the development of drugs. RAR agonists presenting novel structural and chemical features could therefore open new avenues for the discovery of leads against breast, lung and prostate cancer or leukemia. Results We have analysed the induced fit of the active site residues upon binding of a known ligand. The derived binding site models were used to dock over 150,000 molecules in silico (or virtually to the structure of the receptor with the Internal Coordinates Mechanics (ICM program. Thirty ligand candidates were tested in vitro. Conclusions Two novel agonists resulting from the predicted receptor model were active at 50 nM. One of them displays novel structural features which may translate into the development of new ligands for cancer therapy.

  6. Long-acting β2-agonists in asthma

    DEFF Research Database (Denmark)

    Jacobson, Glenn A; Raidal, Sharanne; Hostrup, Morten

    2018-01-01

    Long-acting β2-agonists (LABAs) such as formoterol and salmeterol are used for prolonged bronchodilatation in asthma, usually in combination with inhaled corticosteroids (ICSs). Unexplained paradoxical asthma exacerbations and deaths have been associated with LABAs, particularly when used without...... and effects on BHR, particularly that (S)-enantiomers of β2-agonists may be deleterious to asthma control. LABAs display enantioselective pharmacokinetics and pharmacodynamics. Biological plausibility of the deleterious effects of β2-agonists (S)-enantiomers is provided by in vitro and in vivo studies from...... mechanism in rapid asthma deaths. More effort should therefore be applied to investigating potential enantiospecific effects of LABAs on safety, specifically bronchoprotection. Safety studies directly assessing the effects of LABA (S)-enantiomers on BHR are long overdue....

  7. [Effects of GLP-1 receptor agonists on carbohydrate metabolism control].

    Science.gov (United States)

    Fernández-García, José Carlos; Colomo, Natalia; Tinahones, Francisco José

    2014-09-01

    Glucagon-like peptide-1 (GLP-1) receptor agonists are a new group of drugs for the treatment of type 2 diabetes mellitus (DM2). In the present article, we review the available evidence on the efficacy of GLP-1 receptor agonists as glucose-lowering agents, their place in therapeutic algorithms, and the clinical factors associated with a favorable treatment response. Finally, we describe the clinical characteristics of patients who may benefit from these drugs. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  8. Investigation of the mechanism of radioprotective action of adrenoceptor agonists

    International Nuclear Information System (INIS)

    Kulinskij, V.I.; Klimova, A.D.; Yashunskij, V.G.; Alpatova, T.V.; 4205700SU)

    1986-01-01

    α-Adrenoceptor agonists of both main groups, i.e. arylalkylamines and imidazolines, have a pronounced radioprotective effect. Their chemical analogs, which fail to stimulate α-adrenoceptors, do not protect mice. The effect of phenylephrine, adrenaline, and noradrenaline comes into play via α 1 -adrenoceptors and that of clonidine, via α 2 -adrenoceptors and also via α 1 -adrenoceptors. Adrenoceptor agonists can probably manifest their radioprotective action via both subtypes of α-adrenoceptors. Possible intracellular mechanisms of the radioprotective action are discussed

  9. Thrombopoietin-receptor agonists in haematological disorders: The Danish experience

    DEFF Research Database (Denmark)

    Gudbrandsdottir, Sif; Frederiksen, Henrik; Hasselbalch, Hans

    2011-01-01

    The objective of this study was to investigate the use of thrombopoietin-receptor agonists (TPO-ra) in patients with refractory primary immune thrombocytopenia (ITP) as well as off-label use of TPO-ra in Danish haematology departments. Hospital medical records from 32 of the 39 patients having re...

  10. Use of ß-adrenergic agonists in hybrid catfish

    Science.gov (United States)

    Ractopamine hydrochloride (RH) is a potent ß-adrenergic agonist that has been used in some species of fish to improve growth performance and dress out characteristics. While this metabolic modifier has been shown to have positive effects on growth of fish, little research has focused on the mechani...

  11. Free Fatty Acid Receptor 1 (FFA1/GPR40) Agonists

    DEFF Research Database (Denmark)

    Christiansen, Elisabeth; Due-Hansen, Maria E; Urban, Christian

    2012-01-01

    FFA1 (GPR40) is a new target for treatment of type 2 diabetes. We recently identified the potent FFA1 agonist TUG-469 (5). Inspired by the structurally related TAK-875, we explored the effects of a mesylpropoxy appendage on 5. The appendage significantly lowers lipophilicity and improves metaboli...

  12. Dopamine agonists and risk: impulse control disorders in Parkinson's disease.

    Science.gov (United States)

    Voon, Valerie; Gao, Jennifer; Brezing, Christina; Symmonds, Mkael; Ekanayake, Vindhya; Fernandez, Hubert; Dolan, Raymond J; Hallett, Mark

    2011-05-01

    Impulse control disorders are common in Parkinson's disease, occurring in 13.6% of patients. Using a pharmacological manipulation and a novel risk taking task while performing functional magnetic resonance imaging, we investigated the relationship between dopamine agonists and risk taking in patients with Parkinson's disease with and without impulse control disorders. During functional magnetic resonance imaging, subjects chose between two choices of equal expected value: a 'Sure' choice and a 'Gamble' choice of moderate risk. To commence each trial, in the 'Gain' condition, individuals started at $0 and in the 'Loss' condition individuals started at -$50 below the 'Sure' amount. The difference between the maximum and minimum outcomes from each gamble (i.e. range) was used as an index of risk ('Gamble Risk'). Sixteen healthy volunteers were behaviourally tested. Fourteen impulse control disorder (problem gambling or compulsive shopping) and 14 matched Parkinson's disease controls were tested ON and OFF dopamine agonists. Patients with impulse control disorder made more risky choices in the 'Gain' relative to the 'Loss' condition along with decreased orbitofrontal cortex and anterior cingulate activity, with the opposite observed in Parkinson's disease controls. In patients with impulse control disorder, dopamine agonists were associated with enhanced sensitivity to risk along with decreased ventral striatal activity again with the opposite in Parkinson's disease controls. Patients with impulse control disorder appear to have a bias towards risky choices independent of the effect of loss aversion. Dopamine agonists enhance sensitivity to risk in patients with impulse control disorder possibly by impairing risk evaluation in the striatum. Our results provide a potential explanation of why dopamine agonists may lead to an unconscious bias towards risk in susceptible individuals.

  13. Effect of beta-agonists on LAM progression and treatment.

    Science.gov (United States)

    Le, Kang; Steagall, Wendy K; Stylianou, Mario; Pacheco-Rodriguez, Gustavo; Darling, Thomas N; Vaughan, Martha; Moss, Joel

    2018-01-30

    Lymphangioleiomyomatosis (LAM), a rare disease of women, is associated with cystic lung destruction resulting from the proliferation of abnormal smooth muscle-like LAM cells with mutations in the tuberous sclerosis complex (TSC) genes TSC1 and/or TSC2 The mutant genes and encoded proteins are responsible for activation of the mechanistic target of rapamycin (mTOR), which is inhibited by sirolimus (rapamycin), a drug used to treat LAM. Patients who have LAM may also be treated with bronchodilators for asthma-like symptoms due to LAM. We observed stabilization of forced expiratory volume in 1 s over time in patients receiving sirolimus and long-acting beta-agonists with short-acting rescue inhalers compared with patients receiving only sirolimus. Because beta-agonists increase cAMP and PKA activity, we investigated effects of PKA activation on the mTOR pathway. Human skin TSC2 +/- fibroblasts or LAM lung cells incubated short-term with isoproterenol (beta-agonist) showed a sirolimus-independent increase in phosphorylation of S6, a downstream effector of the mTOR pathway, and increased cell growth. Cells incubated long-term with isoproterenol, which may lead to beta-adrenergic receptor desensitization, did not show increased S6 phosphorylation. Inhibition of PKA blocked the isoproterenol effect on S6 phosphorylation. Thus, activation of PKA by beta-agonists increased phospho-S6 independent of mTOR, an effect abrogated by beta-agonist-driven receptor desensitization. In agreement, retrospective clinical data from patients with LAM suggested that a combination of bronchodilators in conjunction with sirolimus may be preferable to sirolimus alone for stabilization of pulmonary function.

  14. Agonists and partial agonists of rhodopsin: retinal polyene methylation affects receptor activation.

    Science.gov (United States)

    Vogel, Reiner; Lüdeke, Steffen; Siebert, Friedrich; Sakmar, Thomas P; Hirshfeld, Amiram; Sheves, Mordechai

    2006-02-14

    Using Fourier transform infrared (FTIR) difference spectroscopy, we have studied the impact of sites and extent of methylation of the retinal polyene with respect to position and thermodynamic parameters of the conformational equilibrium between the Meta I and Meta II photoproducts of rhodopsin. Deletion of methyl groups to form 9-demethyl and 13-demethyl analogues, as well as addition of a methyl group at C10 or C12, shifted the Meta I/Meta II equilibrium toward Meta I, such that the retinal analogues behaved like partial agonists. This equilibrium shift resulted from an apparent reduction of the entropy gain of the transition of up to 65%, which was only partially offset by a concomitant reduction of the enthalpy increase. The analogues produced Meta II photoproducts with relatively small alterations, while their Meta I states were significantly altered, which accounted for the aberrant transitions to Meta II. Addition of a methyl group at C14 influenced the thermodynamic parameters but had little impact on the position of the Meta I/Meta II equilibrium. Neutralization of the residue 134 in the E134Q opsin mutant increased the Meta II content of the 13-demethyl analogue, but not of the 9-demethyl analogue, indicating a severe impairment of the allosteric coupling between the conserved cytoplasmic ERY motif involved in proton uptake and the Schiff base/Glu 113 microdomain in the 9-demethyl analogue. The 9-methyl group appears therefore essential for the correct positioning of retinal to link protonation of the cytoplasmic motif with protonation of Glu 113 during receptor activation.

  15. GnRH antagonist versus long agonist protocols in IVF

    DEFF Research Database (Denmark)

    Lambalk, C B; Banga, F R; Huirne, J A

    2017-01-01

    BACKGROUND: Most reviews of IVF ovarian stimulation protocols have insufficiently accounted for various patient populations, such as ovulatory women, women with polycystic ovary syndrome (PCOS) or women with poor ovarian response, and have included studies in which the agonist or antagonist...... was not the only variable between the compared study arms. OBJECTIVE AND RATIONALE: The aim of the current study was to compare GnRH antagonist protocols versus standard long agonist protocols in couples undergoing IVF or ICSI, while accounting for various patient populations and treatment schedules. SEARCH...... in couples undergoing IVF or ICSI. The primary outcome was ongoing pregnancy rate. Secondary outcomes were: live birth rate, clinical pregnancy rate, number of oocytes retrieved and safety with regard to ovarian hyperstimulation syndrome (OHSS). Separate comparisons were performed for the general IVF...

  16. Dopamine agonists and risk: impulse control disorders in Parkinson's; disease

    OpenAIRE

    Voon, Valerie; Gao, Jennifer; Brezing, Christina; Symmonds, Mkael; Ekanayake, Vindhya; Fernandez, Hubert; Dolan, Raymond J.; Hallett, Mark

    2011-01-01

    Impulse control disorders are common in Parkinson's; disease, occurring in 13.6% of patients. Using a pharmacological manipulation and a novel risk taking task while performing functional magnetic resonance imaging, we investigated the relationship between dopamine agonists and risk taking in patients with Parkinson's; disease with and without impulse control disorders. During functional magnetic resonance imaging, subjects chose between two choices of equal expected value: a ‘Sure’ choice an...

  17. Improving the developability profile of pyrrolidine progesterone receptor partial agonists

    Energy Technology Data Exchange (ETDEWEB)

    Kallander, Lara S.; Washburn, David G.; Hoang, Tram H.; Frazee, James S.; Stoy, Patrick; Johnson, Latisha; Lu, Qing; Hammond, Marlys; Barton, Linda S.; Patterson, Jaclyn R.; Azzarano, Leonard M.; Nagilla, Rakesh; Madauss, Kevin P.; Williams, Shawn P.; Stewart, Eugene L.; Duraiswami, Chaya; Grygielko, Eugene T.; Xu, Xiaoping; Laping, Nicholas J.; Bray, Jeffrey D.; Thompson, Scott K. (GSKPA)

    2010-09-17

    The previously reported pyrrolidine class of progesterone receptor partial agonists demonstrated excellent potency but suffered from serious liabilities including hERG blockade and high volume of distribution in the rat. The basic pyrrolidine amine was intentionally converted to a sulfonamide, carbamate, or amide to address these liabilities. The evaluation of the degree of partial agonism for these non-basic pyrrolidine derivatives and demonstration of their efficacy in an in vivo model of endometriosis is disclosed herein.

  18. Pharmacophore-driven identification of PPARγ agonists from natural sources

    DEFF Research Database (Denmark)

    Petersen, R. K.; Christensen, Kathrine Bisgaard; Assimopoulou, A. N.

    2011-01-01

    mastic gum fractions, whereas some other sub-fractions exhibited also biological activity towards PPARγ. The results from the present work are two-fold: on the one hand we demonstrate that the pharmacophore model we developed is able to select novel ligand scaffolds that act as PPARγ agonists; while...... at the same time it manifests that natural products are highly relevant for use in virtual screening-based drug discovery....

  19. TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis

    OpenAIRE

    Dietrich, Johannes W.; Landgrafe, Gabi; Fotiadou, Elisavet H.

    2012-01-01

    This paper provides the reader with an overview of our current knowledge of hypothalamic-pituitary-thyroid feedback from a cybernetic standpoint. Over the past decades we have gained a plethora of information from biochemical, clinical, and epidemiological investigation, especially on the role of TSH and other thyrotropic agonists as critical components of this complex relationship. Integrating these data into a systems perspective delivers new insights into static and dynamic behaviour of th...

  20. Suppression of atherosclerosis by synthetic REV-ERB agonist

    Energy Technology Data Exchange (ETDEWEB)

    Sitaula, Sadichha [Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458 (United States); Billon, Cyrielle [Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104 (United States); Kamenecka, Theodore M.; Solt, Laura A. [Department of Molecular Therapeutics, The Scripps Research Institute, Jupiter, FL 33458 (United States); Burris, Thomas P., E-mail: burristp@slu.edu [Department of Pharmacological & Physiological Science, Saint Louis University School of Medicine, St. Louis, MO 63104 (United States)

    2015-05-08

    The nuclear receptors for heme, REV-ERBα and REV-ERBβ, play important roles in the regulation of metabolism and inflammation. Recently it was demonstrated that reduced REV-ERBα expression in hematopoetic cells in LDL receptor null mice led to increased atherosclerosis. We sought to determine if synthetic REV-ERB agonists that we have developed might have the ability to suppress atherosclerosis in this model. A previously characterized synthetic REV-ERB agonist, SR9009, was used to determine if activation of REV-ERB activity would affect atherosclerosis in LDL receptor deficient mice. Atherosclerotic plaque size was significantly reduced (p < 0.05) in mice administered SR9009 (100 mg/kg) for seven weeks compared to control mice (n = 10 per group). SR9009 treatment of bone marrow-derived mouse macrophages (BMDM) reduced the polarization of BMDMs to proinflammatory M1 macrophage while increasing the polarization of BMDMs to anti-inflammatory M2 macrophages. Our results suggest that pharmacological targeting of REV-ERBs may be a viable therapeutic option for treatment of atherosclerosis. - Highlights: • Synthetic REV-ERB agonist treatment reduced atherosclerosis in a mouse model. • Pharmacological activation of REV-ERB decreased M1 macrophage polarization. • Pharmacological activation of REV-ERB increased M2 macrophage polarization.

  1. Dopamine agonist activity of EMD 23,448

    Energy Technology Data Exchange (ETDEWEB)

    Martin, G E; Pettibone, D J [Merck Sharp and Dohme Research Laboratories, West Point, Pennsylvania (USA). Dept. of Pharmacology

    1985-01-01

    EMD 23,448 was examined in tests of dopaminergic function and was found to be an atypical dopamine (DA) agonist. EMD 23,448 was a weak or inactive DA agonist when examined in tests of normal postsynaptic DA receptor function: production of stereotypy in the rat (ED/sub 50/ greater than sign 5.0 mg/kg.i.p.); production of emesis in beagles (minimum effective dose = 81..mu..g/kg i.v.); and, enhanced locomotor activity of the mouse (no excitation in doses <=50 mg/i.p.). Moreover, EMD 23,448 was relatively weak in competing for (/sup 3/H)-apomorphine binding to rat striatal membranes (Ki, 205 nM). On the other hand, this indolyl-3-butylamine did activate supersensitive postsynaptic DA receptors. Specifically, it elicited contralateral turning in rats with a unilateral 6-hydroxydopamine lesion of the substantia nigra (ED/sub 50/ value = 0.9 mg/kg) and did elicit stereotypy in rats given chronic daily haloperidol treatments. EMD 23,448 also exerted pharmacological effects in tests designed to measure activation of dopamine autoreceptors. It inhibited the ..gamma..-butyrolactone-induced increase in striatal dopa levels (ED/sub 50/ = 1 mg/kg i.p.) and produced a dose-related fall in the locomotor activity of the mouse. The results are discussed and contrasted with data derived for apomorphine and the putatively selective autoreceptor agonist (+-)-3-PPP.

  2. Dopamine agonist activity of EMD 23,448

    International Nuclear Information System (INIS)

    Martin, G.E.; Pettibone, D.J.

    1985-01-01

    EMD 23,448 was examined in tests of dopaminergic function and was found to be an atypical dopamine (DA) agonist. EMD 23,448 was a weak or inactive DA agonist when examined in tests of normal postsynaptic DA receptor function: production of stereotypy in the rat (ED 50 greater than sign 5.0 mg/kg.i.p.); production of emesis in beagles (minimum effective dose = 81μg/kg i.v.); and, enhanced locomotor activity of the mouse (no excitation in doses 3 H]-apomorphine binding to rat striatal membranes (Ki, 205 nM). On the other hand, this indolyl-3-butylamine did activate supersensitive postsynaptic DA receptors. Specifically, it elicited contralateral turning in rats with a unilateral 6-hydroxydopamine lesion of the substantia nigra (ED 50 value = 0.9 mg/kg) and did elicit stereotypy in rats given chronic daily haloperidol treatments. EMD 23,448 also exerted pharmacological effects in tests designed to measure activation of dopamine autoreceptors. It inhibited the γ-butyrolactone-induced increase in striatal dopa levels (ED 50 = 1 mg/kg i.p.) and produced a dose-related fall in the locomotor activity of the mouse. The results are discussed and contrasted with data derived for apomorphine and the putatively selective autoreceptor agonist (+-)-3-PPP. (Author)

  3. PPAR Agonists and Metabolic Syndrome: An Established Role?

    Directory of Open Access Journals (Sweden)

    Margherita Botta

    2018-04-01

    Full Text Available Therapeutic approaches to metabolic syndrome (MetS are numerous and may target lipoproteins, blood pressure or anthropometric indices. Peroxisome proliferator-activated receptors (PPARs are involved in the metabolic regulation of lipid and lipoprotein levels, i.e., triglycerides (TGs, blood glucose, and abdominal adiposity. PPARs may be classified into the α, β/δ and γ subtypes. The PPAR-α agonists, mainly fibrates (including newer molecules such as pemafibrate and omega-3 fatty acids, are powerful TG-lowering agents. They mainly affect TG catabolism and, particularly with fibrates, raise the levels of high-density lipoprotein cholesterol (HDL-C. PPAR-γ agonists, mainly glitazones, show a smaller activity on TGs but are powerful glucose-lowering agents. Newer PPAR-α/δ agonists, e.g., elafibranor, have been designed to achieve single drugs with TG-lowering and HDL-C-raising effects, in addition to the insulin-sensitizing and antihyperglycemic effects of glitazones. They also hold promise for the treatment of non-alcoholic fatty liver disease (NAFLD which is closely associated with the MetS. The PPAR system thus offers an important hope in the management of atherogenic dyslipidemias, although concerns regarding potential adverse events such as the rise of plasma creatinine, gallstone formation, drug–drug interactions (i.e., gemfibrozil and myopathy should also be acknowledged.

  4. Development of specific dopamine D-1 agonists and antagonists

    International Nuclear Information System (INIS)

    Sakolchai, S.

    1987-01-01

    To develop potentially selective dopamine D-1 agonists and to investigate on the structural requirement for D-1 activity, the derivatives of dibenzocycloheptadiene are synthesized and pharmacologically evaluated. The target compounds are 5-aminomethyl-10,11-dihydro-1,2-dihydroxy-5H-dibenzo[a,d]cycloheptene hydrobromide 10 and 9,10-dihydroxy-1,2,3,7,8,12b-hexahydrobenzo[1,2]cyclohepta[3,4,5d,e]isoquinoline hydrobromide 11. In a dopamine-sensitive rat retinal adenylate cyclase assay, a model for D-1 activity, compound 10 is essentially inert for both agonist and antagonist activity. In contrast, compound 11 is approximately equipotent to dopamine in activation of the D-1 receptor. Based on radioligand and binding data, IC 50 of compound 11 for displacement of 3 H-SCH 23390, a D-1 ligand, is about 7 fold less than that for displacement of 3 H-spiperone, a D-2 ligand. These data indicate that compound 11 is a potent selective dopamine D-1 agonist. This study provides a new structural class of dopamine D-1 acting agent: dihydroxy-benzocycloheptadiene analog which can serve as a lead compound for further drug development and as a probe for investigation on the nature of dopamine D-1 receptor

  5. The treatment of Parkinson's disease with dopamine agonists

    Directory of Open Access Journals (Sweden)

    Frank, Wilhelm

    2008-06-01

    Full Text Available Parkinson’s disease is a chronic degenerative organic disease with unknown causes. A disappearance of cells with melanin in the substantia nigra is considered as biological artefact of the disease, which causes a degenerative loss of neurons in the corpus striatum of mesencephalon. This structure produces also the transmitter substance dopamine. Due to this disappearance of cells dopamine is not produced in a sufficient quantity which is needed for movement of the body. The questions of this report are concerned the efficiency and safety of a treatment with dopamine agonists. Furthermore the cost-effectiveness is investigated as well as ethic questions. The goal is to give recommendation for the use of dopamine agonists to the German health system. A systematic literature search was done. The identified studies have different methodological quality and investigate different hypothesis and different outcome criteria. Therefore a qualitative method of information synthesis was chosen. Since the introduction of L-Dopa in the 1960´s it is considered as the most effective substance to reduce all the cardinal symptoms of Parkinson disease. This substance was improved in the course of time. Firstly some additional substances were given (decarbonxylase inhibitors, catechol-o-transferase inhibitors (COMT-inhibitors, monoaminoxydase-inhibitors (MAO-inhibitors and NMDA-antagonists (N-Methyl-d-aspartat-antagonists. In the practical therapy of Parkinson dopamine agonists play an important role, because they directly use the dopamine receptors. The monotherapy of Parkinson disease is basically possible and is used in early stages of the disease. Clinical practise has shown, that an add on therapy with dopamine agonists can led to a reduction of the dose of L-dopa and a reduction of following dyskinesia. The studies for effectiveness include studies for the initial therapy, monotherapy and add-on-therapy. Basically there is a good effectiveness of dopamine

  6. Computer models in the design of FXR

    International Nuclear Information System (INIS)

    Vogtlin, G.; Kuenning, R.

    1980-01-01

    Lawrence Livermore National Laboratory is developing a 15 to 20 MeV electron accelerator with a beam current goal of 4 kA. This accelerator will be used for flash radiography and has a requirement of high reliability. Components being developed include spark gaps, Marx generators, water Blumleins and oil insulation systems. A SCEPTRE model was developed that takes into consideration the non-linearity of the ferrite and the time dependency of the emission from a field emitter cathode. This model was used to predict an optimum charge time to obtain maximum magnetic flux change from the ferrite. This model and its application will be discussed. JASON was used extensively to determine optimum locations and shapes of supports and insulators. It was also used to determine stress within bubbles adjacent to walls in oil. Computer results will be shown and bubble breakdown will be related to bubble size

  7. 5α-Bile alcohols function as farnesoid X receptor antagonists

    International Nuclear Information System (INIS)

    Nishimaki-Mogami, Tomoko; Kawahara, Yosuke; Tamehiro, Norimasa; Yoshida, Takemi; Inoue, Kazuhide; Ohno, Yasuo; Nagao, Taku; Une, Mizuho

    2006-01-01

    The farnesoid X receptor (FXR) is a bile acid/alcohol-activated nuclear receptor that regulates lipid homeostasis. Unlike other steroid receptors, FXR binds bile acids in an orientation that allows the steroid nucleus A to face helix 12 in the receptor, a crucial domain for coactivator-recruitment. Because most naturally occurring bile acids and alcohols contain a cis-oriented A, which is distinct from that of other steroids and cholesterol metabolites, we investigated the role of this 5β-configuration in FXR activation. The results showed that the 5β-(A/B cis) bile alcohols 5β-cyprinol and bufol are potent FXR agonists, whereas their 5α-(A/B trans) counterparts antagonize FXR transactivation and target gene expression. Both isomers bound to FXR, but their ability to induce coactivator-recruitment and thereby induce transactivation differed. These findings suggest a critical role for the A orientation of bile salts in agonist/antagonist function

  8. Novel kinin B1 receptor agonists with improved pharmacological profiles.

    Science.gov (United States)

    Côté, Jérôme; Savard, Martin; Bovenzi, Veronica; Bélanger, Simon; Morin, Josée; Neugebauer, Witold; Larouche, Annie; Dubuc, Céléna; Gobeil, Fernand

    2009-04-01

    There is some evidence to suggest that inducible kinin B1 receptors (B1R) may play beneficial and protecting roles in cardiovascular-related pathologies such as hypertension, diabetes, and ischemic organ diseases. Peptide B1R agonists bearing optimized pharmacological features (high potency, selectivity and stability toward proteolysis) hold promise as valuable therapeutic agents in the treatment of these diseases. In the present study, we used solid-phase methodology to synthesize a series of novel peptide analogues based on the sequence of Sar[dPhe(8)]desArg(9)-bradykinin, a relatively stable peptide agonist with moderate affinity for the human B1R. We evaluated the pharmacological properties of these peptides using (1) in vitro competitive binding experiments on recombinant human B1R and B2R (for index of selectivity determination) in transiently transfected human embryonic kidney 293 cells (HEK-293T cells), (2) ex vivo vasomotor assays on isolated human umbilical veins expressing endogenous human B1R, and (3) in vivo blood pressure tests using anesthetized lipopolysaccharide-immunostimulated rabbits. Key chemical modifications at the N-terminus, the positions 3 and 5 on Sar[dPhe(8)]desArg(9)-bradykinin led to potent analogues. For example, peptides 18 (SarLys[Hyp(3),Cha(5), dPhe(8)]desArg(9)-bradykinin) and 20 (SarLys[Hyp(3),Igl(5), dPhe(8)]desArg(9)-bradykinin) outperformed the parental molecule in terms of affinity, functional potency and duration of action in vitro and in vivo. These selective agonists should be valuable in future animal and human studies to investigate the potential benefits of B1R activation.

  9. Cardiovascular safety and benefits of GLP-1 receptor agonists

    DEFF Research Database (Denmark)

    Dalsgaard, Niels B; Brønden, Andreas; Lauritsen, Tina Vilsbøll

    2017-01-01

    INTRODUCTION: Glucagon-like peptide-1 (GLP-1) receptor agonists (GLP-1RAs) constitute a class of drugs for the treatment of type 2 diabetes, and currently, six different GLP-1RAs are approved. Besides improving glycemic control, the GLP-1RAs have other beneficial effects such as weight loss...... and a low risk of hypoglycemia. Treatment with the GLP-1RA lixisenatide has been shown to be safe in patients with type 2 diabetes and recent acute coronary syndrome. Furthermore, liraglutide and semaglutide have been shown to reduce cardiovascular (CV) disease (CVD) risk in type 2 diabetes patients...

  10. Discovery of a potent and selective GPR120 agonist

    DEFF Research Database (Denmark)

    Shimpukade, Bharat; Hudson, Brian D; Hovgaard, Christine Kiel

    2012-01-01

    GPR120 is a receptor of unsaturated long-chain fatty acids reported to mediate GLP-1 secretion, insulin sensitization, anti-inflammatory, and anti-obesity effects and is therefore emerging as a new potential target for treatment of type 2 diabetes and metabolic diseases. Further investigation...... is however hindered by the lack of suitable receptor modulators. Screening of FFA1 ligands provided a lead with moderate activity on GPR120 and moderate selectivity over FFA1. Optimization led to the discovery of the first potent and selective GPR120 agonist....

  11. Mechanical stress activates NMDA receptors in the absence of agonists

    OpenAIRE

    Maneshi, Mohammad Mehdi; Maki, Bruce; Gnanasambandam, Radhakrishnan; Belin, Sophie; Popescu, Gabriela K.; Sachs, Frederick; Hua, Susan Z.

    2017-01-01

    While studying the physiological response of primary rat astrocytes to fluid shear stress in a model of traumatic brain injury (TBI), we found that shear stress induced Ca2+ entry. The influx was inhibited by MK-801, a specific pore blocker of N-Methyl-D-aspartic acid receptor (NMDAR) channels, and this occurred in the absence of agonists. Other NMDA open channel blockers ketamine and memantine showed a similar effect. The competitive glutamate antagonists AP5 and GluN2B-selective inhibitor i...

  12. Dihydroartemisinin protects against alcoholic liver injury through alleviating hepatocyte steatosis in a farnesoid X receptor-dependent manner

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Wenxuan; Lu, Chunfeng; Yao, Lu; Zhang, Feng; Shao, Jiangjuan [Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province (China); Zheng, Shizhong, E-mail: nytws@163.com [Department of Pharmacology, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province (China); Jiangsu Key Laboratory for Pharmacology and Safety Evaluation of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing, Jiangsu Province (China)

    2017-01-15

    Alcoholic liver disease (ALD) is a common etiology of liver diseases, characterized by hepatic steatosis. We previously identified farnesoid X receptor (FXR) as a potential therapeutic target for ALD. Dihydroartemisinin (DHA) has been recently identified to possess potent pharmacological activities on liver diseases. This study was aimed to explore the impact of DHA on ALD and further elaborate the underlying mechanisms. Gain- or loss-of-function analyses of FXR were applied in both in vivo and in vitro studies. Results demonstrated that DHA rescued FXR expression and activity in alcoholic rat livers. DHA also reduced serodiagnostic markers of liver injury, including aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase. DHA improved alcohol-induced liver histological lesions, expression of inflammation genes, and inflammatory cell infiltration. In addition, DHA not only attenuated hyperlipidemia but also reduced hepatic steatosis through regulating lipogenesis and lipolysis genes. In vitro experiments further consolidated the concept that DHA ameliorated ethanol-caused hepatocyte injury and steatosis. Noteworthily, DHA effects were reinforced by FXR agonist obeticholic acid or FXR expression plasmids but abrogated by FXR antagonist Z-guggulsterone or FXR siRNA. In summary, DHA significantly improved alcoholic liver injury by inhibiting hepatic steatosis, which was dependent on its activation of FXR in hepatocytes. - Highlights: • DHA rescues FXR expression in alcoholic livers. • DHA improves alcoholic liver inflammation and steatosis in a FXR-dependent way. • DHA alleviates ethanol-induced hepatocyte steatosis by activation of FXR.

  13. Dihydroartemisinin protects against alcoholic liver injury through alleviating hepatocyte steatosis in a farnesoid X receptor-dependent manner

    International Nuclear Information System (INIS)

    Xu, Wenxuan; Lu, Chunfeng; Yao, Lu; Zhang, Feng; Shao, Jiangjuan; Zheng, Shizhong

    2017-01-01

    Alcoholic liver disease (ALD) is a common etiology of liver diseases, characterized by hepatic steatosis. We previously identified farnesoid X receptor (FXR) as a potential therapeutic target for ALD. Dihydroartemisinin (DHA) has been recently identified to possess potent pharmacological activities on liver diseases. This study was aimed to explore the impact of DHA on ALD and further elaborate the underlying mechanisms. Gain- or loss-of-function analyses of FXR were applied in both in vivo and in vitro studies. Results demonstrated that DHA rescued FXR expression and activity in alcoholic rat livers. DHA also reduced serodiagnostic markers of liver injury, including aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, and lactate dehydrogenase. DHA improved alcohol-induced liver histological lesions, expression of inflammation genes, and inflammatory cell infiltration. In addition, DHA not only attenuated hyperlipidemia but also reduced hepatic steatosis through regulating lipogenesis and lipolysis genes. In vitro experiments further consolidated the concept that DHA ameliorated ethanol-caused hepatocyte injury and steatosis. Noteworthily, DHA effects were reinforced by FXR agonist obeticholic acid or FXR expression plasmids but abrogated by FXR antagonist Z-guggulsterone or FXR siRNA. In summary, DHA significantly improved alcoholic liver injury by inhibiting hepatic steatosis, which was dependent on its activation of FXR in hepatocytes. - Highlights: • DHA rescues FXR expression in alcoholic livers. • DHA improves alcoholic liver inflammation and steatosis in a FXR-dependent way. • DHA alleviates ethanol-induced hepatocyte steatosis by activation of FXR.

  14. The Good, the Bad, and the Ugly: Agonistic Behaviour in Juvenile Crocodilians

    OpenAIRE

    Brien, Matthew L.; Lang, Jeffrey W.; Webb, Grahame J.; Stevenson, Colin; Christian, Keith A.

    2013-01-01

    We examined agonistic behaviour in seven species of hatchling and juvenile crocodilians held in small groups (N = 4) under similar laboratory conditions. Agonistic interactions occurred in all seven species, typically involved two individuals, were short in duration (5-15 seconds), and occurred between 1600-2200 h in open water. The nature and extent of agonistic interactions, the behaviours displayed, and the level of conspecific tolerance varied among species. Discrete postures, non-contact...

  15. Innate Immune Responses to TLR2 and TLR4 Agonists Differ between Baboons, Chimpanzees and Humans

    Science.gov (United States)

    Brinkworth, Jessica F.; Pechenkina, Ekaterina A.; Silver, Jack; Goyert, Sanna M.

    2012-01-01

    Background African catarrhine primates differ in bacterial disease susceptibility. Methods Human, chimpanzee, and baboon blood was stimulated with TLR-detected bacterial agonists and cytokine/chemokine induction assessed by real-time pcr. Results Humans and chimpanzees shared similar cytokine/chemokine responses, while baboon cytokine/chemokine induction differed. Generally, responses were agonist-independent. Conclusions These primates tend to generate species rather than agonist–specific responses to bacterial agonists. PMID:22978822

  16. Contamination with retinoic acid receptor agonists in two rivers in the Kinki region of Japan.

    Science.gov (United States)

    Inoue, Daisuke; Nakama, Koki; Sawada, Kazuko; Watanabe, Taro; Takagi, Mai; Sei, Kazunari; Yang, Min; Hirotsuji, Junji; Hu, Jianying; Nishikawa, Jun-ichi; Nakanishi, Tsuyoshi; Ike, Michihiko

    2010-04-01

    This study was conducted to investigate the agonistic activity against human retinoic acid receptor (RAR) alpha in the Lake Biwa-Yodo River and the Ina River in the Kinki region of Japan. To accomplish this, a yeast two-hybrid assay was used to elucidate the spatial and temporal variations and potential sources of RARalpha agonist contamination in the river basins. RARalpha agonistic activity was commonly detected in the surface water samples collected along two rivers at different periods, with maximum all-trans retinoic acid (atRA) equivalents of 47.6 ng-atRA/L and 23.5 ng-atRA/L being observed in Lake Biwa-Yodo River and Ina River, respectively. The results indicated that RARalpha agonists are always present and widespread in the rivers. Comparative investigation of RARalpha and estrogen receptor alpha agonistic activities at 20 stations along each river revealed that the spatial variation pattern of RARalpha agonist contamination was entirely different from that of the estrogenic compound contamination. This suggests that the effluent from municipal wastewater treatment plants, a primary source of estrogenic compounds, seemed not to be the cause of RARalpha agonist contamination in the rivers. Fractionation using high performance liquid chromatography (HPLC) directed by the bioassay found two bioactive fractions from river water samples, suggesting the presence of at least two RARalpha agonists in the rivers. Although a trial conducted to identify RARalpha agonists in the major bioactive fraction was not completed as part of this study, comparison of retention times in HPLC analysis and quantification with liquid chromatography-mass spectrometry analysis revealed that the major causative contaminants responsible for the RARalpha agonistic activity were not RAs (natural RAR ligands) and 4-oxo-RAs, while 4-oxo-RAs were identified as the major RAR agonists in sewage in Beijing, China. These findings suggest that there are unknown RARalpha agonists with high

  17. Analysis of agonist dissociation constants as assessed by functional antagonism in guinea pig left atria

    International Nuclear Information System (INIS)

    Molenaar, P.; Malta, E.

    1986-01-01

    In electrically driven guinea pig left atria, positive inotropic responses to (-)-isoprenaline and the selective beta 1-adrenoceptor agonist RO363 were obtained in the absence and in the presence of the functional antagonists adenosine, carbachol, gallopamil, nifedipine, and Ro 03-7894. Each of the functional antagonists reduced the maximum response to both agonists and produced nonparallel rightward shifts in the cumulative concentration effect curves. For both agonists, dissociation constants (KA) were calculated using the equation described by Furchgott (1966) for irreversible antagonism. For RO363, which is a partial agonist with high agonist activity, the equations outlined for functional interaction by Mackay (1981) were also employed to calculate KA values. The KA values obtained by each method were compared with the dissociation constants (KD) for the two agonists determined from their ability to displace the radioligand (-)-[ 125 I]iodocyanopindolol from beta 1-adrenoceptors in guinea pig left atrial membrane preparations. The estimates of KA varied substantially from KD values. The KD values were taken as more accurate estimates of the true values for the dissociation constants because a high degree of correlation exists between pKD and pD2 values for a number of other beta-adrenoceptor agonists that behave as partial agonists and between pKD and pKB values for a number of beta-adrenoceptor antagonists. Thus, it appears that there are serious limitations in the current theory for using functional antagonism as a means of obtaining agonist dissociation constants

  18. Long-acting beta(2)-agonists in management of childhood asthma

    DEFF Research Database (Denmark)

    Bisgaard, H

    2000-01-01

    This review assesses the evidence regarding the use of long-acting beta(2)-agonists in the management of pediatric asthma. Thirty double-blind, randomized, controlled trials on the effects of formoterol and salmeterol on lung function in asthmatic children were identified. Single doses of inhaled......, long-acting beta(2)-agonists provide effective bronchodilatation and bronchoprotection when used as intermittent, single-dose treatment of asthma in children, but not when used as regular treatment. Future studies should examine the positioning of long-acting beta(2)-agonists as an "as needed" rescue...... medication instead of short-acting beta(2)-agonists for pediatric asthma management....

  19. Hypertrophic effect of inhaled beta -agonist with and without concurrent exercise training

    DEFF Research Database (Denmark)

    Jessen, Søren; Onslev, Johan; Lemminger, Anders

    2018-01-01

    INTRODUCTION: Due to a high prevalence of asthma and exercise-induced bronchoconstriction in elite athletes, there is a high use of beta2 -adrenoceptor agonists (beta2 -agonists) in the athletic population. While anabolic in rodents, no study has been able to detect hypertrophy in humans after...... chronic beta2 -agonist inhalation. METHODS: We investigated if inhaled beta2 -agonist, terbutaline, alters body composition and metabolic rate with and without concurrent exercise training in healthy young men. Sixty-seven participants completed a four-week intervention of daily terbutaline (8×0.5 mg...

  20. Agonist-induced affinity alterations of a central nervous system. cap alpha. -bungarotoxin receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lukas, R.J.; Bennett, E.L.

    1979-01-01

    The ability of cholinergic agonists to block the specific interaction of ..cap alpha..-bungarotoxin (..cap alpha..-Bgt) with membrane-bound sites derived from rat brain is enhanced when membranes are preincubated with agonist. Thus, pretreatment of ..cap alpha..-Bgt receptors with agonist (but not antagonist) causes transformation of sites to a high-affinity form toward agonist. This change in receptor state occurs with a half-time on the order of minutes, and is fully reversible on dilution of agonist. The results are consistent with the identity of ..cap alpha..-Bgt binding sites as true central nicotinic acetylcholine receptors. Furthermore, this agonist-induced alteration in receptor state may represent an in vitro correlate of physiological desensitization. As determined from the effects of agonist on toxin binding isotherms, and on the rate of toxin binding to specific sites, agonist inhibition of toxin binding to the high-affinity state is non-competitive. This result suggests that there may exist discrete toxin-binding and agonist-binding sites on central toxin receptors.

  1. AMP is an adenosine A1 receptor agonist.

    Science.gov (United States)

    Rittiner, Joseph E; Korboukh, Ilia; Hull-Ryde, Emily A; Jin, Jian; Janzen, William P; Frye, Stephen V; Zylka, Mark J

    2012-02-17

    Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5'-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5'-monophosphonate, ACP) directly activated the adenosine A(1) receptor (A(1)R). In contrast, AMP only activated the adenosine A(2B) receptor (A(2B)R) after hydrolysis to adenosine by ecto-5'-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A(1)R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A(1)R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A(1)R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A(1)R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine.

  2. NKT-cell glycolipid agonist as adjuvant in synthetic vaccine.

    Science.gov (United States)

    Liu, Zheng; Guo, Jun

    2017-11-27

    NKT cells are CD1d-restricted, glycolipid antigen-reactive, immunoregulatory T lymphocytes that can serve as a bridge between the innate and adaptive immunities. NKT cells have a wide range of therapeutic application in autoimmunity, transplant biology, infectious disease, cancer, and vaccinology. Rather than triggering "danger signal" and eliciting an innate immune response, αGalCer-based NKT-cell agonist act via a unique mechanism, recruiting NKT cells which play a T helper-like role even without peptide as Th epitope. Importantly, the non-polymorphism of CD1d render glycolipid a universal helper epitope, offering the potential to simplify the vaccine construct capable of eliciting consistent immune response in different individuals. This review details recent advances in the design of synthetic vaccines using NKT-cell agonist as adjuvant, highlighting the role of organic synthesis and conjugation technique to enhance the immunological actives and to simplify the vaccine constructs. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. Mood Disorders, Circadian Rhythms, Melatonin and Melatonin Agonists

    Directory of Open Access Journals (Sweden)

    M.A. Quera Salva

    2012-04-01

    Full Text Available Recent advances in the understanding of circadian rhythms have led to an interest in the treatment of major depressive disorder with chronobiotic agents. Many tissues have autonomous circadian rhythms, which are orchestrated by the master clock, situated in the suprachiasmatic nucleus (SNC. Melatonin (N-acetyl-5-hydroxytryptamine is secreted from the pineal gland during darkness. Melatonin acts mainly on MT1 and MT2 receptors, which are present in the SNC, regulating physiological and neuroendocrine functions, including circadian entrainment, referred to as the chronobiotic effet. Circadian rhythms has been shown to be either misaligned or phase shifted or decreased in amplitude in both acute episodes and relapse of major depressive disorder (MDD and bipolar disorder. Manipulation of circadian rhythms either using physical treatments (such as high intensity light or behavioral therapy has shown promise in improving symptoms. Pharmacotherapy using melatonin and pure melatonin receptor agonists, while improving sleep, has not been shown to improve symptoms of depression. A novel antidepressant, agomelatine, combines 5HT2c antagonist and melatonin agonist action, and has shown promise in both acute treatment of MDD and in preventing relapse.

  4. Cold suppresses agonist-induced activation of TRPV1.

    Science.gov (United States)

    Chung, M-K; Wang, S

    2011-09-01

    Cold therapy is frequently used to reduce pain and edema following acute injury or surgery such as tooth extraction. However, the neurobiological mechanisms of cold therapy are not completely understood. Transient receptor potential vanilloid 1 (TRPV1) is a capsaicin- and heat-gated nociceptive ion channel implicated in thermosensation and pathological pain under conditions of inflammation or injury. Although capsaicin-induced nociception, neuropeptide release, and ionic currents are suppressed by cold, it is not known if cold suppresses agonist-induced activation of recombinant TRPV1. We demonstrate that cold strongly suppressed the activation of recombinant TRPV1 by multiple agonists and capsaicin-evoked currents in trigeminal ganglia neurons under normal and phosphorylated conditions. Cold-induced suppression was partially impaired in a TRPV1 mutant that lacked heat-mediated activation and potentiation. These results suggest that cold-induced suppression of TRPV1 may share a common molecular basis with heat-induced potentiation, and that allosteric inhibition may contribute, in part, to the cold-induced suppression. We also show that combination of cold and a specific antagonist of TRPV1 can produce an additive suppression. Our results provide a mechanistic basis for cold therapy and may enhance anti-nociceptive approaches that target TRPV1 for managing pain under inflammation and tissue injury, including that from tooth extraction.

  5. Identification of agonists for a group of human odorant receptors

    Directory of Open Access Journals (Sweden)

    Daniela eGonzalez-Kristeller

    2015-03-01

    Full Text Available Olfaction plays a critical role in several aspects of the human life. Odorants are detected by hundreds of odorant receptors (ORs which belong to the superfamily of G protein-coupled receptors. These receptors are expressed in the olfactory sensory neurons of the nose. The information provided by the activation of different combinations of ORs in the nose is transmitted to the brain, leading to odorant perception and emotional and behavioral responses. There are ~400 intact human ORs, and to date only a small percentage of these receptors (~10% have known agonists. The determination of the specificity of the human ORs will contribute to a better understanding of how odorants are discriminated by the olfactory system. In this work, we aimed to identify human specific ORs, that is, ORs that are present in humans but absent from other species, and their corresponding agonists. To do this, we first selected 22 OR gene sequences from the human genome with no counterparts in the mouse, rat or dog genomes. Then we used a heterologous expression system to screen a subset of these human ORs against a panel of odorants of biological relevance, including foodborne aroma volatiles. We found that different types of odorants are able to activate some of these previously uncharacterized human ORs.

  6. Trial Watch: Toll-like receptor agonists in oncological indications.

    Science.gov (United States)

    Aranda, Fernando; Vacchelli, Erika; Obrist, Florine; Eggermont, Alexander; Galon, Jérôme; Sautès-Fridman, Catherine; Cremer, Isabelle; Henrik Ter Meulen, Jan; Zitvogel, Laurence; Kroemer, Guido; Galluzzi, Lorenzo

    2014-01-01

    Toll-like receptors (TLRs) are an evolutionarily conserved group of enzymatically inactive, single membrane-spanning proteins that recognize a wide panel of exogenous and endogenous danger signals. Besides constituting a crucial component of the innate immune response to bacterial and viral pathogens, TLRs appear to play a major role in anticancer immunosurveillance. In line with this notion, several natural and synthetic TLR ligands have been intensively investigated for their ability to boost tumor-targeting immune responses elicited by a variety of immunotherapeutic and chemotherapeutic interventions. Three of these agents are currently approved by the US Food and Drug Administration (FDA) or equivalent regulatory agencies for use in cancer patients: the so-called bacillus Calmette-Guérin, monophosphoryl lipid A, and imiquimod. However, the number of clinical trials testing the therapeutic potential of both FDA-approved and experimental TLR agonists in cancer patients is stably decreasing, suggesting that drug developers and oncologists are refocusing their interest on alternative immunostimulatory agents. Here, we summarize recent findings on the use of TLR agonists in cancer patients and discuss how the clinical evaluation of FDA-approved and experimental TLR ligands has evolved since the publication of our first Trial Watch dealing with this topic.

  7. How does agonistic behaviour differ in albino and pigmented fish?

    Directory of Open Access Journals (Sweden)

    Ondřej Slavík

    2016-04-01

    Full Text Available In addition to hypopigmentation of the skin and red iris colouration, albino animals also display distinct physiological and behavioural alterations. However, information on the social interactions of albino animals is rare and has mostly been limited to specially bred strains of albino rodents and animals from unique environments in caves. Differentiating between the effects of albinism and domestication on behaviour in rodents can be difficult, and social behaviour in cave fish changes according to species-specific adaptations to conditions of permanent darkness. The agonistic behaviours of albino offspring of pigmented parents have yet to be described. In this study, we observed agonistic behaviour in albino and pigmented juvenile Silurus glanis catfish. We found that the total number of aggressive interactions was lower in albinos than in pigmented catfish. The distance between conspecifics was also analysed, and albinos showed a tendency towards greater separation from their same-coloured conspecifics compared with pigmented catfish. These results demonstrate that albinism can be associated with lower aggressiveness and with reduced shoaling behaviour preference, as demonstrated by a tendency towards greater separation of albinos from conspecifics.

  8. Pharmacology and toxicology of Cannabis derivatives and endocannabinoid agonists.

    Science.gov (United States)

    Gerra, Gilberto; Zaimovic, Amir; Gerra, Maria L; Ciccocioppo, Roberto; Cippitelli, Andrea; Serpelloni, Giovanni; Somaini, Lorenzo

    2010-01-01

    For centuries Cannabis sativa and cannabis extracts have been used in natural medicine. Delta(9)-tetrahydrocannabinol (THC) is the main active ingredient of Cannabis. THC seems to be responsible for most of the pharmacological and therapeutic actions of cannabis. In a few countries THC extracts (i.e. Sativex) or THC derivatives such as nabilone, and dronabinol are used in the clinic for the treatment of several pathological conditions like chemotherapy-induced nausea and vomiting, multiple sclerosis and glaucoma. On the other hand the severe side effects and the high abuse liability of these agents represent a serious limitation in their medical use. In addition, diversion in the use of these active ingredients for recreational purpose is a concern. Over recent years, alternative approaches using synthetic cannabinoid receptor agonists or agents acting as activators of the endocannabinoid systems are under scrutiny with the hope to develop more effective and safer clinical applications. Likely, in the near future few of these new molecules will be available for clinical use. The present article review recent study and patents with focus on the cannabinoid system as a target for the treatment of central nervous system disorders with emphasis on agonists.

  9. PPAR-alpha agonists as novel antiepileptic drugs: preclinical findings.

    Directory of Open Access Journals (Sweden)

    Monica Puligheddu

    Full Text Available Nicotinic acetylcholine receptors (nAChRs are involved in seizure mechanisms. Hence, nocturnal frontal lobe epilepsy was the first idiopathic epilepsy linked with specific mutations in α4 or β2 nAChR subunit genes. These mutations confer gain of function to nAChRs by increasing sensitivity toward acetylcholine. Consistently, nicotine elicits seizures through nAChRs and mimics the excessive nAChR activation observed in animal models of the disease. Treatments aimed at reducing nicotinic inputs are sought as therapies for epilepsies where these receptors contribute to neuronal excitation and synchronization. Previous studies demonstrated that peroxisome proliferator-activated receptors-α (PPARα, nuclear receptor transcription factors, suppress nicotine-induced behavioral and electrophysiological effects by modulating nAChRs containing β2 subunits. On these bases, we tested whether PPARα agonists were protective against nicotine-induced seizures. To this aim we utilized behavioral and electroencephalographic (EEG experiments in C57BL/J6 mice and in vitro patch clamp recordings from mice and rats. Convulsive doses of nicotine evoked severe seizures and bursts of spike-waves discharges in ∼100% of mice. A single dose of the synthetic PPARα agonist WY14643 (WY, 80 mg/kg, i.p. or chronic administration of fenofibrate, clinically available for lipid metabolism disorders, in the diet (0.2% for 14 days significantly reduced or abolished behavioral and EEG expressions of nicotine-induced seizures. Acute WY effects were reverted by the PPARα antagonist MK886 (3 mg/kg, i.p.. Since neocortical networks are crucial in the generation of ictal activity and synchrony, we performed patch clamp recordings of spontaneous inhibitory postsynaptic currents (sIPSCs from frontal cortex layer II/III pyramidal neurons. We found that both acute and chronic treatment with PPARα agonists abolished nicotine-induced sIPSC increases. PPARα within the CNS are key

  10. The 5-HT(1F) receptor agonist lasmiditan as a potential treatment of migraine attacks

    DEFF Research Database (Denmark)

    Tfelt-Hansen, Peer C; Olesen, Jes

    2012-01-01

    Lasmiditan is a novel selective 5-HT(1F) receptor agonist. It is both scientifically and clinically relevant to review whether a 5-HT(1F) receptor agonist is effective in the acute treatment of migraine. Two RCTs in the phase II development of lasmiditan was reviewed. In the intravenous placebo...

  11. Trialkyltin rexinoid-X receptor agonists selectively potentiate thyroid hormone induced programs of xenopus laevis metamorphosis

    NARCIS (Netherlands)

    Mengeling, Brenda J.; Murk, Albertinka J.; Furlow, J.D.

    2016-01-01

    The trialkyltins tributyltin (TBT) and triphenyltin (TPT) can function as rexinoid-X receptor (RXR) agonists. We recently showed that RXR agonists can alter thyroid hormone (TH) signaling in a mammalian pituitary TH-responsive reporter cell line, GH3.TRE-Luc. The prevalence of TBT and TPT in the

  12. Low-dose add-back therapy during postoperative GnRH agonist treatment

    Directory of Open Access Journals (Sweden)

    Hsiao-Wen Tsai

    2016-02-01

    Conclusion: Low dose add-back therapy could effectively ameliorate hypoestrogenic side effects and simultaneously maintain the therapeutic response of GnRH agonist treatment. The treatment dropout was lower compared with a regular dose. Therefore, low dose add-back therapy can be considered a treatment choice during postoperative GnRH agonist treatment.

  13. Small-molecule agonists for the glucagon-like peptide 1 receptor

    DEFF Research Database (Denmark)

    Knudsen, Lotte Bjerre; Kiel, Dan; Teng, Min

    2007-01-01

    and independent agonists. Potency of GLP-1 was not changed by the allosteric agonists, but affinity of GLP-1 for the receptor was increased. The most potent compound identified stimulates glucose-dependent insulin release from normal mouse islets but, importantly, not from GLP-1 receptor knockout mice. Also...

  14. Prolonging survival of corneal transplantation by selective sphingosine-1-phosphate receptor 1 agonist.

    Directory of Open Access Journals (Sweden)

    Min Gao

    Full Text Available Corneal transplantation is the most used therapy for eye disorders. Although the cornea is somewhat an immune privileged organ, immune rejection is still the major problem that reduces the success rate. Therefore, effective chemical drugs that regulate immunoreactions are needed to improve the outcome of corneal transplantations. Here, a sphingosine-1-phosphate receptor 1 (S1P1 selective agonist was systematically evaluated in mouse allogeneic corneal transplantation and compared with the commonly used immunosuppressive agents. Compared with CsA and the non-selective sphingosine 1-phosphate (S1P receptor agonist FTY720, the S1P1 selective agonist can prolong the survival corneal transplantation for more than 30 days with a low immune response. More importantly, the optimal dose of the S1P1 selective agonist was much less than non-selective S1P receptor agonist FTY720, which would reduce the dose-dependent toxicity in drug application. Then we analyzed the mechanisms of the selected S1P1 selective agonist on the immunosuppression. The results shown that the S1P1 selective agonist could regulate the distribution of the immune cells with less CD4+ T cells and enhanced Treg cells in the allograft, moreover the expression of anti-inflammatory cytokines TGF-β1 and IL-10 unregulated which can reduce the immunoreactions. These findings suggest that S1P1 selective agonist may be a more appropriate immunosuppressive compound to effectively prolong mouse allogeneic corneal grafts survival.

  15. Click-Chemistry-Mediated Synthesis of Selective Melanocortin Receptor 4 Agonists

    DEFF Research Database (Denmark)

    Palmer, Daniel; Gonçalves, Juliana P.L.; Hansen, Louise V.

    2017-01-01

    The melanocortin receptor 4 (MC4R) subtype of the melanocortin receptor family is a target for therapeutics to ameliorate metabolic dysfunction. Endogenous MC4R agonists possess a critical pharmacophore (HFRW), and cyclization of peptide agonists often enhances potency. Thus, 17 cyclized peptides...

  16. Agonist-induced desensitization of human β3-adrenoceptors expressed in human embryonic kidney cells

    NARCIS (Netherlands)

    Michel-Reher, Martina B.; Michel, Martin C.

    2013-01-01

    β3-Adrenoceptors are resistant to agonist-induced desensitization in some cell types but susceptible in others including transfected human embryonic kidney (HEK) cells. Therefore, we have studied cellular and molecular changes involved in agonist-induced β3-adrenoceptor desensitization in HEK cells.

  17. Long-acting beta 2-agonists in chronic obstructive pulmonary disease.

    Science.gov (United States)

    Llewellyn-Jones, Carol

    2002-01-01

    Until recently, the use of long-acting beta 2-agonists in chronic obstructive pulmonary disease has been understated. There is now evidence that they may offer benefits beyond bronchodilation. This article reviews the management of chronic obstructive pulmonary disease and looks at the place of long-acting beta 2-agonists as a first-line treatment option.

  18. Long-term outcome of patients with macroprolactinomas initially treated with dopamine agonists

    NARCIS (Netherlands)

    Kars, Marleen; Pereira, Alberto M.; Smit, Johannes W.; Romijn, Johannes A.

    2009-01-01

    Dopamine agonists are the first line therapy for the treatment of prolactinomas. The aim of this study was to assess the outcome of macroprolactinomas during long-term follow-up after initial treatment with dopamine agonists. Retrospective follow-up study. We included 72 consecutive patients (age

  19. Helminthosporic acid functions as an agonist for gibberellin receptor.

    Science.gov (United States)

    Miyazaki, Sho; Jiang, Kai; Kobayashi, Masatomo; Asami, Tadao; Nakajima, Masatoshi

    2017-11-01

    Helminthosporol was isolated from a fungus, Helminthosporium sativum, as a natural plant growth regulator in 1963. It showed gibberellin-like bioactivity that stimulated the growth of the second leaf sheath of rice. After studying the structure-activity relationship between the compound and some synthesized analogs, it was found that helminthosporic acid (H-acid) has higher gibberellin-like activity and chemical stability than helminthosporol. In this study, we showed that (1) H-acid displays gibberellin-like activities not only in rice but also in Arabidopsis, (2) it regulates the expression of gibberellin-related genes, (3) it induces DELLA degradation through binding with a gibberellin receptor (GID1), and (4) it forms the GID1-(H-acid)-DELLA complex to transduce the gibberellin signal in the same manner as gibberellin. This work shows that the H-acid mode of action acts as an agonist for gibberellin receptor.

  20. PPAR Agonists: Potential as Therapeutics for Neovascular Retinopathies

    Directory of Open Access Journals (Sweden)

    Harrihar A. Pershadsingh

    2008-01-01

    Full Text Available The angiogenic, neovascular proliferative retinopathies, proliferative diabetic retinopathy (PDR, and age-dependent macular degeneration (AMD complicated by choroidal neovascularization (CNV, also termed exudative or “wet” AMD, are common causes of blindness. The antidiabetic thiazolidinediones (TZDs, rosiglitazone, and troglitazone are PPAR agonists with demonstrable antiproliferative, and anti-inflammatory effects, in vivo, were shown to ameliorate PDR and CNV in rodent models, implying the potential efficacy of TZDs for treating proliferative retinopathies in humans. Activation of the angiotensin II type 1 receptor (AT1-R propagates proinflammatory and proliferative pathogenic determinants underlying PDR and CNV. The antihypertensive dual AT1-R blocker (ARB, telmisartan, recently was shown to activate PPAR and improve glucose and lipid metabolism and to clinically improve PDR and CNV in rodent models. Therefore, the TZDs and telmisartan, clinically approved antidiabetic and antihypertensive drugs, respectively, may be efficacious for treating and attenuating PDR and CNV humans. Clinical trials are needed to test these possibilities.

  1. Climate Change Journalism: From Agony to Agonistic Debate

    Directory of Open Access Journals (Sweden)

    Yves Pepermans

    2017-04-01

    Full Text Available Starting from a politicized outlook on climate change, this essay criticizes mainstream journalistic norms for failing to enable an agonistic, democratic debate about how to move forward. Based on a targeted search for examples from the reporting (and reflection thereof of two Dutch-speaking alternative news sites (DeWereldMorgen and De Correspondent, we seek to illustrate how their respective (climate journalists look for truth, generate democratic debate and hold power accountable by combining practices from constructive journalism, slow journalism and advocacy journalism. We find these journalists to focus on patterns, root causes and underlying values, rather than on novelty or exceptional events. Furthermore, an impartial and detached style of reporting is explicitly denounced in favor of an open and reflexive choice of news-making based on advocacy.

  2. TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis

    Science.gov (United States)

    Dietrich, Johannes W.; Landgrafe, Gabi; Fotiadou, Elisavet H.

    2012-01-01

    This paper provides the reader with an overview of our current knowledge of hypothalamic-pituitary-thyroid feedback from a cybernetic standpoint. Over the past decades we have gained a plethora of information from biochemical, clinical, and epidemiological investigation, especially on the role of TSH and other thyrotropic agonists as critical components of this complex relationship. Integrating these data into a systems perspective delivers new insights into static and dynamic behaviour of thyroid homeostasis. Explicit usage of this information with mathematical methods promises to deliver a better understanding of thyrotropic feedback control and new options for personalised diagnosis of thyroid dysfunction and targeted therapy, also by permitting a new perspective on the conundrum of the TSH reference range. PMID:23365787

  3. TSH and Thyrotropic Agonists: Key Actors in Thyroid Homeostasis

    Directory of Open Access Journals (Sweden)

    Johannes W. Dietrich

    2012-01-01

    Full Text Available This paper provides the reader with an overview of our current knowledge of hypothalamic-pituitary-thyroid feedback from a cybernetic standpoint. Over the past decades we have gained a plethora of information from biochemical, clinical, and epidemiological investigation, especially on the role of TSH and other thyrotropic agonists as critical components of this complex relationship. Integrating these data into a systems perspective delivers new insights into static and dynamic behaviour of thyroid homeostasis. Explicit usage of this information with mathematical methods promises to deliver a better understanding of thyrotropic feedback control and new options for personalised diagnosis of thyroid dysfunction and targeted therapy, also by permitting a new perspective on the conundrum of the TSH reference range.

  4. INSIGHT AGONISTES: A READING OF SOPHOCLES'S OEDIPUS THE KING.

    Science.gov (United States)

    Mahon, Eugene J

    2015-07-01

    In this reading of Sophocles's Oedipus the King, the author suggests that insight can be thought of as the main protagonist of the tragedy. He personifies this depiction of insight, calling it Insight Agonistes, as if it were the sole conflicted character on the stage, albeit masquerading at times as several other characters, including gods, sphinxes, and oracles. This psychoanalytic reading of the text lends itself to an analogy between psychoanalytic process and Sophocles's tragic hero. The author views insight as always transgressing against, always at war with a conservative, societal, or intrapsychic chorus of structured elements. A clinical vignette is presented to illustrate this view of insight. © 2015 The Psychoanalytic Quarterly, Inc.

  5. N-methyl-D-aspartic acid receptor agonists

    DEFF Research Database (Denmark)

    Madsen, U; Frydenvang, Karla Andrea; Ebert, B

    1996-01-01

    (R,S)-2-Amino-2-(3-hydroxy-5-methyl-4-isoxazolyl)acetic acid [(R,S)-AMAA, 4] is a potent and selective agonist at the N-methyl-D-aspartic acid (NMDA) subtype of excitatory amino acid receptors. Using the Ugi "four-component condensation" method, the two diastereomers (2R)- and (2S)-2-[3-(benzyloxy......) showed peak affinity for [3H]AMPA receptor sites (IC50 = 72 +/- 13 microM) and was shown to be a more potent inhibitor of [3H]CPP binding (IC50 = 3.7 +/- 1.5 microM) than (S)-AMAA (9) (IC50 = 61 +/- 6.4 microM). Neither enantiomer of AMAA affected [3H]kainic acid receptor binding significantly...

  6. [Safety and tolerability of GLP-1 receptor agonists].

    Science.gov (United States)

    Soldevila, Berta; Puig-Domingo, Manel

    2014-09-01

    Glucagon-like peptide-1 receptor agonists (GLP-1ra) are a new group of drugs with a glucose-lowering action due to their incretin effect. The GLP-1 receptor is expressed in various human tissues, which could be related to the pleiotropic effects of human GLP-1, as well as to the adverse effects described in patients treated with GLP-1ra. The risk of hypoglycaemia is low, which is one of the main considerations in the safety of this family of compounds and is also important to patients with diabetes. The most frequent adverse effect is nausea, which usually occurs at the start of treatment and is transient in 20-60% of affected patients. This article also reviews the information available on antibody formation, the potential effect on the thyroid gland, and the controversial association between this group of drugs with pancreatitis and cancer. Copyright © 2014 Elsevier España, S.L.U. All rights reserved.

  7. Effect of obeticholic acid on liver regeneration following portal vein embolization in an experimental model

    NARCIS (Netherlands)

    Olthof, P. B.; Huisman, F.; Schaap, F. G.; van Lienden, K. P.; Bennink, R. J.; van Golen, R. F.; Heger, M.; Verheij, J.; Jansen, P. L.; Olde Damink, S. W.; van Gulik, T. M.

    2017-01-01

    The bile salt-activated transcription factor farnesoid X receptor (FXR) is a key mediator of proliferative bile salt signalling, which is assumed to play a role in the early phase of compensatory liver growth. The aim of this study was to evaluate the effect of a potent FXR agonist (obeticholic

  8. Could Dopamine Agonists Aid in Drug Development for Anorexia Nervosa?

    Science.gov (United States)

    Frank, Guido K. W.

    2014-01-01

    Anorexia nervosa is a severe psychiatric disorder most commonly starting during the teenage-years and associated with food refusal and low body weight. Typically there is a loss of menses, intense fear of gaining weight, and an often delusional quality of altered body perception. Anorexia nervosa is also associated with a pattern of high cognitive rigidity, which may contribute to treatment resistance and relapse. The complex interplay of state and trait biological, psychological, and social factors has complicated identifying neurobiological mechanisms that contribute to the illness. The dopamine D1 and D2 neurotransmitter receptors are involved in motivational aspects of food approach, fear extinction, and cognitive flexibility. They could therefore be important targets to improve core and associated behaviors in anorexia nervosa. Treatment with dopamine antagonists has shown little benefit, and it is possible that antagonists over time increase an already hypersensitive dopamine pathway activity in anorexia nervosa. On the contrary, application of dopamine receptor agonists could reduce circuit responsiveness, facilitate fear extinction, and improve cognitive flexibility in anorexia nervosa, as they may be particularly effective during underweight and low gonadal hormone states. This article provides evidence that the dopamine receptor system could be a key factor in the pathophysiology of anorexia nervosa and dopamine agonists could be helpful in reducing core symptoms of the disorder. This review is a theoretical approach that primarily focuses on dopamine receptor function as this system has been mechanistically better described than other neurotransmitters that are altered in anorexia nervosa. However, those proposed dopamine mechanisms in anorexia nervosa also warrant further study with respect to their interaction with other neurotransmitter systems, such as serotonin pathways. PMID:25988121

  9. AMP Is an Adenosine A1 Receptor Agonist*

    Science.gov (United States)

    Rittiner, Joseph E.; Korboukh, Ilia; Hull-Ryde, Emily A.; Jin, Jian; Janzen, William P.; Frye, Stephen V.; Zylka, Mark J.

    2012-01-01

    Numerous receptors for ATP, ADP, and adenosine exist; however, it is currently unknown whether a receptor for the related nucleotide adenosine 5′-monophosphate (AMP) exists. Using a novel cell-based assay to visualize adenosine receptor activation in real time, we found that AMP and a non-hydrolyzable AMP analog (deoxyadenosine 5′-monophosphonate, ACP) directly activated the adenosine A1 receptor (A1R). In contrast, AMP only activated the adenosine A2B receptor (A2BR) after hydrolysis to adenosine by ecto-5′-nucleotidase (NT5E, CD73) or prostatic acid phosphatase (PAP, ACPP). Adenosine and AMP were equipotent human A1R agonists in our real-time assay and in a cAMP accumulation assay. ACP also depressed cAMP levels in mouse cortical neurons through activation of endogenous A1R. Non-selective purinergic receptor antagonists (pyridoxalphosphate-6-azophenyl-2′,4′-disulfonic acid and suramin) did not block adenosine- or AMP-evoked activation. Moreover, mutation of His-251 in the human A1R ligand binding pocket reduced AMP potency without affecting adenosine potency. In contrast, mutation of a different binding pocket residue (His-278) eliminated responses to AMP and to adenosine. Taken together, our study indicates that the physiologically relevant nucleotide AMP is a full agonist of A1R. In addition, our study suggests that some of the physiological effects of AMP may be direct, and not indirect through ectonucleotidases that hydrolyze this nucleotide to adenosine. PMID:22215671

  10. Could dopamine agonists aid in drug development for anorexia nervosa?

    Science.gov (United States)

    Frank, Guido K W

    2014-01-01

    Anorexia nervosa is a severe psychiatric disorder most commonly starting during the teenage-years and associated with food refusal and low body weight. Typically there is a loss of menses, intense fear of gaining weight, and an often delusional quality of altered body perception. Anorexia nervosa is also associated with a pattern of high cognitive rigidity, which may contribute to treatment resistance and relapse. The complex interplay of state and trait biological, psychological, and social factors has complicated identifying neurobiological mechanisms that contribute to the illness. The dopamine D1 and D2 neurotransmitter receptors are involved in motivational aspects of food approach, fear extinction, and cognitive flexibility. They could therefore be important targets to improve core and associated behaviors in anorexia nervosa. Treatment with dopamine antagonists has shown little benefit, and it is possible that antagonists over time increase an already hypersensitive dopamine pathway activity in anorexia nervosa. On the contrary, application of dopamine receptor agonists could reduce circuit responsiveness, facilitate fear extinction, and improve cognitive flexibility in anorexia nervosa, as they may be particularly effective during underweight and low gonadal hormone states. This article provides evidence that the dopamine receptor system could be a key factor in the pathophysiology of anorexia nervosa and dopamine agonists could be helpful in reducing core symptoms of the disorder. This review is a theoretical approach that primarily focuses on dopamine receptor function as this system has been mechanistically better described than other neurotransmitters that are altered in anorexia nervosa. However, those proposed dopamine mechanisms in anorexia nervosa also warrant further study with respect to their interaction with other neurotransmitter systems, such as serotonin pathways.

  11. Could Dopamine Agonists Aid in Drug Development for Anorexia Nervosa?

    Directory of Open Access Journals (Sweden)

    Guido eFrank

    2014-11-01

    Full Text Available Anorexia nervosa is a severe psychiatric disorder most commonly starting during the teenage years and associated with food refusal and low body weight. Typically there is a loss of menses, intense fear of gaining weight and an often delusional quality of altered body perception. Anorexia nervosa is also associated with a pattern of high cognitive rigidity, which may contribute to treatment resistance and relapse. The complex interplay of state and trait biological, psychological and social factors has complicated identifying neurobiological mechanisms that contribute to the illness. The dopamine D1 and D2 neurotransmitter receptors are involved in motivational aspects of food approach, fear extinction and cognitive flexibility. They could therefore be important targets to improve core and associated behaviors in anorexia nervosa. Treatment with dopamine antagonists has shown little benefit, and it is possible that antagonists over time increase an already hypersensitive dopamine pathway activity in anorexia nervosa. On the contrary, application of dopamine receptor agonists could reduce circuit responsiveness, facilitate fear extinction and improve cognitive flexibility in anorexia nervosa, as they may be particularly effective during underweight and low gonadal hormone states. This article provides evidence that the dopamine receptor system could be a key factor in the pathophysiology of anorexia nervosa and dopamine agonists could be helpful in reducing core symptoms of the disorder. This review is a theoretical approach that primarily focuses on dopamine receptor function as this system has been mechanistically better described than other neurotransmitters that are altered in anorexia nervosa. However, those proposed dopamine mechanisms in anorexia nervosa also warrant further study with respect to their interaction with other neurotransmitter systems, such as serotonin pathways.

  12. Metabolic effects of beta2-agonists in relation to exercise performance

    DEFF Research Database (Denmark)

    Kalsen, Anders

    2015-01-01

    athletes. The present PhD thesis is based on four manuscripts in which the acute effects of beta2-agonists on exercise performance were investigated. The aims were 1) to investigate whether supratherapeutic inhalation of beta2-agonists enhances muscle strength, anaerobic performance and aerobic performance......, 2) to uncover the mechanisms behind potential beta2-adrenergic improvements in anaerobic performance, 3) to investigate whether inhalation of beta2-agonists is ergogenic in elite athletes with or without airway hyperresponsiveness (AHR). Results from the studies of the thesis show...... administration of a certain dose, but a further increase in dose does not seem to elicit a greater performance-enhancing effect. Moreover, the effects of beta2-agonists on performance are unaffected by training status and AHR, but athletes with AHR who regularly use beta2-agonists get a reduced ergogenic...

  13. The emergence of devastating impulse control disorders during dopamine agonist therapy of the restless legs syndrome.

    Science.gov (United States)

    Dang, Dien; Cunnington, David; Swieca, John

    2011-01-01

    The Restless Legs Syndrome is a common sensorimotor disorder, typically amenable to treatment with dopamine agonist therapy. Dopamine agonists have been associated with emergent impulse control disorders (ICDs) when used in patients with Parkinson disease, and ICDs have now been reported in individuals with RLS on dopamine agonist therapy. Our aim was to characterize cases of emergent ICDs in Australian patients with focus on the dopamine agonists implicated and the social significance of ICDs. A series of RLS patients on dopamine agonist therapy were identified with ICDs over a 2-year period. Additional cases of ICDs were found using a mailout questionnaire designed to capture those with high impulsivity. These patients were assessed using the Barratt Impulsiveness Scale, Version 11, and a modified Minnesota Impulse Disorders Interview. Case records and medication schedules were evaluated. Twelve cases of patients with de novo ICDs were found with a range of impulsive behaviors including pathological gambling, kleptomania, compulsive shopping, and hypersexuality. Criminality, suicidality, and marital discord also were featured. These occurred over a wide range of latencies and l-dopa exposures. This group of Australian RLS patients with ICDs display high levels of impulsivity and is the first to use the BIS-11 questionnaire in this setting. Impulse control disorders can occur over a wide range of dopamine agonist therapy types and dose exposures. Impulse control disorder tendencies may persist, despite withdrawal of dopamine agonists. The emergence of ICDs needs careful consideration in light of their potentially devastating financial, social, and marital consequences.

  14. Ascorbic acid enables reversible dopamine receptor 3H-agonist binding

    International Nuclear Information System (INIS)

    Leff, S.; Sibley, D.R.; Hamblin, M.; Creese, I.

    1981-01-01

    The effects of ascorbic acid on dopaminergic 3 H-agonist receptor binding were studied in membrane homogenates of bovine anterior pituitary and caudate, and rat striatum. In all tissues virtually no stereospecific binding (defined using 1uM (+)butaclamol) of the 3 H-agonists N-propylnorapomorphine (NPA), apomorphine, or dopamine could be demonstrated in the absence of ascorbic acid. Although levels of total 3 H-agonist binding were three to five times greater in the absence than in the presence of 0.1% ascorbic acid, the increased binding was entirely non-stereospecific. Greater amounts of dopamine-inhibitable 3 H-NPA binding could be demonstrated in the absence of 0.1% ascorbic acid, but this measure of ''specific binding'' was demonstrated not to represent dopamine receptor binding since several other catecholamines and catechol were equipotent with dopamine and more potent than the dopamine agonist (+/-)amino-6,7-dihydroxy-1,2,3,4-tetrahydronapthalene (ADTN) in inhibiting this binding. High levels of dopamine-displaceable 3 H-agonist binding were detected in fresh and boiled homogenates of cerebellum, an area of brain which receives no dopaminergic innervation, further demonstrating the non-specific nature of 3 H-agonist binding in the absence of ascorbic acid. These studies emphasize that under typical assay conditions ascorbic acid is required in order to demonstrate reversible and specific 3 H-agonist binding to dopamine receptors

  15. Binding Mode of Insulin Receptor and Agonist Peptide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Insulin is a protein hormone secreted by pancreatic β cells. One of its main functions is to keep the balance of glucose inside the body by regulating the absorption and metabolism of glucose in the periphery tissue, as well as the production and storage of hepatic glycogen. The insulin receptor is a transmembrane glycoprotein in which two α subunits with a molecular weight of 135 kD and twoβ subunits with a molecular weight of 95 kD are joined by a disulfide bond to form a β-α-α-β structure. The extracellular α subunit, especially, its three domains near the N-terminal are partially responsible for signal transduction or ligand-binding, as indicated by the experiments. The extracellular α subunits are involved in binding the ligands. The experimental results indicate that the three domains of the N-terminal of the α subunits are the main determinative parts of the insulin receptor to bind the insulin or mimetic peptide.We employed the extracellular domain (PDBID: 1IGR) of the insulin-like growth factor-1 receptor (IGF-1 R ) as the template to simulate and optimize the spatial structures of the three domains in the extracellular domain of the insulin receptor, which includes 468 residues. The work was accomplished by making use of the homology program in the Insight Ⅱ package on an Origin3800 server. The docking calculations of the insulin receptor obtained by homology with hexapeptides were carried out by means of the program Affinity. The analysis indicated that there were hydrogen bonding, and electrostatic and hydrophobic effects in the docking complex of the insulin receptor with hexapeptides.Moreover, we described the spatial orientation of a mimetic peptide with agonist activity in the docking complex. We obtained a rough model of binding of DLAPSQ or STIVYS with the insulin receptor, which provides the powerful theoretical support for designing the minimal insulin mimetic peptide with agonist activity, making it possible to develop oral small

  16. Inhibition by TRPA1 agonists of compound action potentials in the frog sciatic nerve

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, Akitomo; Ohtsubo, Sena; Fujita, Tsugumi; Kumamoto, Eiichi, E-mail: kumamote@cc.saga-u.ac.jp

    2013-04-26

    Highlights: •TRPA1 agonists inhibited compound action potentials in frog sciatic nerves. •This inhibition was not mediated by TRPA1 channels. •This efficacy was comparable to those of lidocaine and cocaine. •We found for the first time an ability of TRPA1 agonists to inhibit nerve conduction. -- Abstract: Although TRPV1 and TRPM8 agonists (vanilloid capsaicin and menthol, respectively) at high concentrations inhibit action potential conduction, it remains to be unknown whether TRPA1 agonists have a similar action. The present study examined the actions of TRPA1 agonists, cinnamaldehyde (CA) and allyl isothiocyanate (AITC), which differ in chemical structure from each other, on compound action potentials (CAPs) recorded from the frog sciatic nerve by using the air-gap method. CA and AITC concentration-dependently reduced the peak amplitude of the CAP with the IC{sub 50} values of 1.2 and 1.5 mM, respectively; these activities were resistant to a non-selective TRP antagonist ruthenium red or a selective TRPA1 antagonist HC-030031. The CA and AITC actions were distinct in property; the latter but not former action was delayed in onset and partially reversible, and CA but not AITC increased thresholds to elicit CAPs. A CAP inhibition was seen by hydroxy-α-sanshool (by 60% at 0.05 mM), which activates both TRPA1 and TRPV1 channels, a non-vanilloid TRPV1 agonist piperine (by 20% at 0.07 mM) and tetrahydrolavandulol (where the six-membered ring of menthol is opened; IC{sub 50} = 0.38 mM). It is suggested that TRPA1 agonists as well as TRPV1 and TRPM8 agonists have an ability to inhibit nerve conduction without TRP activation, although their agonists are quite different in chemical structure from each other.

  17. Regulation of ventilation and oxygen consumption by delta- and mu-opioid receptor agonists.

    Science.gov (United States)

    Schaeffer, J I; Haddad, G G

    1985-09-01

    To study the effect of endorphins on metabolic rate and on the relationship between O2 consumption (VO2) and ventilation, we administered enkephalin analogues (relatively selective delta-receptor agonists) and a morphiceptin analogue (a highly selective mu-receptor agonist) intracisternally in nine unanesthetized chronically instrumented adult dogs. Both delta- and mu-agonists decreased VO2 by 40-60%. delta-Agonists induced a dose-dependent decrease in mean instantaneous minute ventilation (VT/TT) associated with periodic breathing. The decrease in VT/TT started and resolved prior to the decrease and returned to baseline of VO2, respectively. In contrast, the mu-agonists induced an increase in VT/TT associated with rapid shallow breathing. Arterial PCO2 increased and arterial PO2 decreased after both delta- and mu-agonists. Low doses of intracisternal naloxone (0.002-2.0 micrograms/kg) reversed the opioid effect on VT/TT but not on VO2; higher doses of naloxone (5-25 micrograms/kg) reversed both. Naloxone administered alone had no effect on VT/TT or VO2. These data suggest that 1) both delta- and mu-agonists induce alveolar hypoventilation despite a decrease in VO2, 2) this hypoventilation results from a decrease in VT/TT after delta-agonists but an increase in dead space ventilation after mu-agonists, and 3) endorphins do not modulate ventilation and metabolic rate tonically, but we speculate that they may do so in response to stressful stimulation.

  18. Interleukin-24 as a target cytokine of environmental aryl hydrocarbon receptor agonist exposure in the lung

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yueh-Hsia; Kuo, Yu-Chun; Tsai, Ming-Hsien; Ho, Chia-Chi; Tsai, Hui-Ti; Hsu, Chin-Yu; Chen, Yu-Cheng; Lin, Pinpin, E-mail: pplin@nhri.org.tw

    2017-06-01

    Exposure to environmental aryl hydrocarbon receptor (AhR) agonists, such as halogenated aromatic hydrocarbons and polycyclic aromatic hydrocarbons (PAHs), has great impacts on the development of various lung diseases. As emerging molecular targets for AhR agonists, cytokines may contribute to the inflammatory or immunotoxic effects of environmental AhR agonists. However, general cytokine expression may not specifically indicate environmental AhR agonist exposure. By comparing cytokine and chemokine expression profiles in human lung adenocarcinoma cell line CL5 treated with AhR agonists and the non-AhR agonist polychlorinated biphenyl (PCB) 39, we identified a target cytokine of environmental AhR agonist exposure of in the lungs. Thirteen cytokine and chemokine genes were altered in the AhR agonists-treated cells, but none were altered in the PCB39-treated cells. Interleukin (IL)-24 was the most highly induced gene among AhR-modulated cytokines. Cotreatment with AhR antagonist completely prevented IL-24 induction by AhR agonists in the CL5 cells. Knockdown AhR expression with short-hairpin RNA (shRNA) significantly reduced benzo[a]pyrene (BaP)-induced IL-24 mRNA levels. We further confirmed that gene transcription, but not mRNA stability, was involved in IL-24 upregulation by BaP. Particulate matter (PM) in the ambient air contains some PAHs and is reported to activate AhR. Oropharyngeal aspiration of PM significantly increased IL-24 levels in lung epithelia and in bronchoalveolar lavage fluid of mice 4 weeks after treatment. Thus, our data suggests that IL-24 is a pulmonary exposure target cytokine of environmental AhR agonists. - Graphical abstract: (A) Cytokine and chemokine gene expressions were examined in CL5 cells treated with AhR and non-AhR agonists. Thirteen cytokines and chemokines genes were altered in the AhR agonist-treated cells, but not in the non-AhR agonist-treated cells. IL-24 was the most highly induced gene among the AhR-modulated cytokines. (B

  19. Triptans, serotonin agonists, and serotonin syndrome (serotonin toxicity): a review.

    Science.gov (United States)

    Gillman, P Ken

    2010-02-01

    The US Food and Drug Administration (FDA) have suggested that fatal serotonin syndrome (SS) is possible with selective serotonin reuptake inhibitors (SSRIs) and triptans: this warning affects millions of patients as these drugs are frequently given simultaneously. SS is a complex topic about which there is much misinformation. The misconception that 5-HT1A receptors can cause serious SS is still widely perpetuated, despite quality evidence that it is activation of the 5-HT2A receptor that is required for serious SS. This review considers SS involving serotonin agonists: ergotamine, lysergic acid diethylamide, bromocriptine, and buspirone, as well as triptans, and reviews the experimental foundation underpinning the latest understanding of SS. It is concluded that there is neither significant clinical evidence, nor theoretical reason, to entertain speculation about serious SS from triptans and SSRIs. The misunderstandings about SS exhibited by the FDA, and shared by the UK Medicines and Healthcare products Regulatory Agency (in relation to methylene blue), are an important issue with wide ramifications.

  20. Neurotensin Agonist Attenuates Nicotine Potentiation to Cocaine Sensitization

    Directory of Open Access Journals (Sweden)

    Paul Fredrickson

    2014-01-01

    Full Text Available Tobacco usage typically precedes illicit drug use in adolescent and young adult populations. Several animal studies suggest nicotine increases the risk for subsequent cocaine abuse, and may be a negative prognostic factor for treatment of cocaine addiction; i.e., a “gateway drug”. Neurotensin (NT is a 13-amino acid neuropeptide that modulates dopamine, acetylcholine, glutamate, and GABA neurotransmission in brain reward pathways. NT69L, a NT(8-13 analog, blocks behavioral sensitization (an animal model for psychostimulant addiction to nicotine, and nicotine self-administration in rats. The present study tested the effect of NT69L on the potentiating effects of nicotine on cocaine-induced locomotor sensitization. Male Wistar rats were injected daily for seven days with nicotine or saline (control followed by four daily injections of cocaine. NT69L was administered 30 min prior to the last cocaine injection. Behavior was recorded with the use of activity chambers. Subchronic administration of nicotine enhanced cocaine-induced behavioral sensitization in Wistar rats, consistent with an hypothesized gateway effect. These behavioral effects of cocaine were attenuated by pretreatment with NT69L. The effect of the neurotensin agonist on cocaine sensitization in the nicotine treated group indicated a possible therapeutic effect for cocaine addiction, even in the presence of enhanced behavioral sensitization induced by nicotine.

  1. Agonist Binding to Chemosensory Receptors: A Systematic Bioinformatics Analysis

    Directory of Open Access Journals (Sweden)

    Fabrizio Fierro

    2017-09-01

    Full Text Available Human G-protein coupled receptors (hGPCRs constitute a large and highly pharmaceutically relevant membrane receptor superfamily. About half of the hGPCRs' family members are chemosensory receptors, involved in bitter taste and olfaction, along with a variety of other physiological processes. Hence these receptors constitute promising targets for pharmaceutical intervention. Molecular modeling has been so far the most important tool to get insights on agonist binding and receptor activation. Here we investigate both aspects by bioinformatics-based predictions across all bitter taste and odorant receptors for which site-directed mutagenesis data are available. First, we observe that state-of-the-art homology modeling combined with previously used docking procedures turned out to reproduce only a limited fraction of ligand/receptor interactions inferred by experiments. This is most probably caused by the low sequence identity with available structural templates, which limits the accuracy of the protein model and in particular of the side-chains' orientations. Methods which transcend the limited sampling of the conformational space of docking may improve the predictions. As an example corroborating this, we review here multi-scale simulations from our lab and show that, for the three complexes studied so far, they significantly enhance the predictive power of the computational approach. Second, our bioinformatics analysis provides support to previous claims that several residues, including those at positions 1.50, 2.50, and 7.52, are involved in receptor activation.

  2. Mechanical stress activates NMDA receptors in the absence of agonists.

    Science.gov (United States)

    Maneshi, Mohammad Mehdi; Maki, Bruce; Gnanasambandam, Radhakrishnan; Belin, Sophie; Popescu, Gabriela K; Sachs, Frederick; Hua, Susan Z

    2017-01-03

    While studying the physiological response of primary rat astrocytes to fluid shear stress in a model of traumatic brain injury (TBI), we found that shear stress induced Ca 2+ entry. The influx was inhibited by MK-801, a specific pore blocker of N-Methyl-D-aspartic acid receptor (NMDAR) channels, and this occurred in the absence of agonists. Other NMDA open channel blockers ketamine and memantine showed a similar effect. The competitive glutamate antagonists AP5 and GluN2B-selective inhibitor ifenprodil reduced NMDA-activated currents, but had no effect on the mechanically induced Ca 2+ influx. Extracellular Mg 2+ at 2 mM did not significantly affect the shear induced Ca 2+ influx, but at 10 mM it produced significant inhibition. Patch clamp experiments showed mechanical activation of NMDAR and inhibition by MK-801. The mechanical sensitivity of NMDARs may play a role in the normal physiology of fluid flow in the glymphatic system and it has obvious relevance to TBI.

  3. PPAR Agonists for the Prevention and Treatment of Lung Cancer

    Directory of Open Access Journals (Sweden)

    Sowmya P. Lakshmi

    2017-01-01

    Full Text Available Lung cancer is the most common and most fatal of all malignancies worldwide. Furthermore, with more than half of all lung cancer patients presenting with distant metastases at the time of initial diagnosis, the overall prognosis for the disease is poor. There is thus a desperate need for new prevention and treatment strategies. Recently, a family of nuclear hormone receptors, the peroxisome proliferator-activated receptors (PPARs, has attracted significant attention for its role in various malignancies including lung cancer. Three PPARs, PPARα, PPARβ/δ, and PPARγ, display distinct biological activities and varied influences on lung cancer biology. PPARα activation generally inhibits tumorigenesis through its antiangiogenic and anti-inflammatory effects. Activated PPARγ is also antitumorigenic and antimetastatic, regulating several functions of cancer cells and controlling the tumor microenvironment. Unlike PPARα and PPARγ, whether PPARβ/δ activation is anti- or protumorigenic or even inconsequential currently remains an open question that requires additional investigation. This review of current literature emphasizes the multifaceted effects of PPAR agonists in lung cancer and discusses how they may be applied as novel therapeutic strategies for the disease.

  4. Urolinin: The First Linear Peptidic Urotensin-II Receptor Agonist.

    Science.gov (United States)

    Bandholtz, Sebastian; Erdmann, Sarah; von Hacht, Jan Lennart; Exner, Samantha; Krause, Gerd; Kleinau, Gunnar; Grötzinger, Carsten

    2016-11-23

    This study investigated the role of individual U-II amino acid positions and side chain characteristics important for U-IIR activation. A complete permutation library of 209 U-II variants was studied in an activity screen that contained single substitution variants of each position with one of the other 19 proteinogenic amino acids. Receptor activation was measured using a cell-based high-throughput fluorescence calcium mobilization assay. We generated the first complete U-II substitution map for U-II receptor activation, resulting in a detailed view into the structural features required for receptor activation, accompanied by complementary information from receptor modeling and ligand docking studies. On the basis of the systematic SAR study of U-II, we created 33 further short and linear U-II variants from eight to three amino acids in length, including d- and other non-natural amino acids. We identified the first high-potency linear U-II analogues. Urolinin, a linear U-II agonist (nWWK-Tyr(3-NO 2 )-Abu), shows low nanomolar potency as well as improved metabolic stability.

  5. Allosteric enhancers, allosteric agonists and ago-allosteric modulators: where do they bind and how do they act?

    DEFF Research Database (Denmark)

    Schwartz, Thue W; Holst, Birgitte

    2007-01-01

    Many small-molecule agonists also display allosteric properties. Such ago-allosteric modulators act as co-agonists, providing additive efficacy--instead of partial antagonism--and they can affect--and often improve--the potency of the endogenous agonist. Surprisingly, the apparent binding sites...... different binding modes. In another, dimeric, receptor scenario, the endogenous agonist binds to one protomer while the ago-allosteric modulator binds to the other, 'allosteric' protomer. It is suggested that testing for ago-allosteric properties should be an integral part of the agonist drug discovery...... process because a compound that acts with--rather than against--the endogenous agonist could be an optimal agonist drug....

  6. Structure and biological activity of endogenous and synthetic agonists of GPR119

    Science.gov (United States)

    Tyurenkov, I. N.; Ozerov, A. A.; Kurkin, D. V.; Logvinova, E. O.; Bakulin, D. A.; Volotova, E. V.; Borodin, D. D.

    2018-02-01

    A G-protein-coupled receptor, GPR119, is a promising pharmacological target for a new class of hypoglycaemic drugs with an original mechanism of action, namely, increase in the glucose-dependent incretin and insulin secretion. In 2005, the first ligands were found and in the subsequent years, a large number of GPR119 agonists were synthesized in laboratories in various countries; the safest and most promising agonists have entered phase I and II clinical trials as agents for the treatment of type 2 diabetes mellitus and obesity. The review describes the major endogenous GPR119 agonists and the main trends in the design and modification of synthetic structures for increasing the hypoglycaemic activity. The data on synthetic agonists are arranged according to the type of the central core of the molecules. The bibliography includes 104 references.

  7. β3-adrenoceptor mediates β3-selective agonist-induced effects on ...

    African Journals Online (AJOL)

    β3-adrenoceptor mediates β3-selective agonist-induced effects on energy expenditure, insulin secrtion and food ... Journal of the Ghana Science Association ... is usually associated with obesity, also involves defective energy expenditure, ...

  8. Discovery of novel acetanilide derivatives as potent and selective beta3-adrenergic receptor agonists.

    Science.gov (United States)

    Maruyama, Tatsuya; Onda, Kenichi; Hayakawa, Masahiko; Matsui, Tetsuo; Takasu, Toshiyuki; Ohta, Mitsuaki

    2009-06-01

    In the search for potent and selective human beta3-adrenergic receptor (AR) agonists as potential drugs for the treatment of obesity and noninsulin-dependent (type II) diabetes, a novel series of acetanilide-based analogues were prepared and their biological activities were evaluated at the human beta3-, beta2-, and beta1-ARs. Among these compounds, 2-pyridylacetanilide (2f), pyrimidin-2-ylacetanilide (2u), and pyrazin-2-ylacetanilide (2v) derivatives exhibited potent agonistic activity at the beta3-AR with functional selectivity over the beta1- and beta2-ARs. In particular, compound 2u was found to be the most potent and selective beta3-AR agonist with an EC(50) value of 0.11 microM and no agonistic activity for either the beta1- or beta2-AR. In addition, 2f, 2u, and 2v showed significant hypoglycemic activity in a rodent diabetic model.

  9. Non-Acidic Free Fatty Acid Receptor 4 Agonists with Antidiabetic Activity

    DEFF Research Database (Denmark)

    Goncalves de Azavedo, Carlos M. B. P.; Watterson, Kenneth R; Wargent, Ed T

    2016-01-01

    The free fatty acid receptor 4 (FFA4 or GPR120) has appeared as an interesting potential target for the treatment of metabolic disorders. At present, most FFA4 ligands are carboxylic acids that are assumed to mimic the endogenous long-chain fatty acid agonists. Here, we report preliminary structure......-activity relationship studies of a previously disclosed non-acidic sulfonamide FFA4 agonist. Mutagenesis studies indicate that the compounds are orthosteric agonists despite the absence of a carboxylate function. The preferred compounds showed full agonist activity on FFA4 and complete selectivity over FFA1, although...... a significant fraction of these non-carboxylic acids also showed partial antagonistic activity on FFA1. Studies in normal and diet-induced obese (DIO) mice with the preferred compound 34 showed improved glucose tolerance after oral dosing in an oral glucose tolerance test. Chronic dosing of 34 in DIO mice...

  10. Minimal_Set_of_In_Vitro_ER_Agonist_Assays_Selection_RegToxPharm_Data

    Data.gov (United States)

    U.S. Environmental Protection Agency — A dataset for the manuscript which demonstrates that it is possible to achieve levels of performance equivalent to the full 16 assay ER agonist model against both in...

  11. Serotonin 2A receptor agonist binding in the human brain with [C]Cimbi-36

    DEFF Research Database (Denmark)

    Ettrup, A.; da Cunha-Bang, S.; McMahon, Barry P.

    2014-01-01

    [C]Cimbi-36 was recently developed as a selective serotonin 2A (5-HT) receptor agonist radioligand for positron emission tomography (PET) brain imaging. Such an agonist PET radioligand may provide a novel, and more functional, measure of the serotonergic system and agonist binding is more likely ....... Thus, we here describe [C]Cimbi-36 as the first agonist PET radioligand to successfully image and quantify 5-HT receptors in the human brain.Journal of Cerebral Blood Flow & Metabolism advance online publication, 30 April 2014; doi:10.1038/jcbfm.2014.68....... than antagonist binding to reflect 5-HT levels in vivo. Here, we show data from a first-in-human clinical trial with [C]Cimbi-36. In 29 healthy volunteers, we found high brain uptake and distribution according to 5-HT receptors with [C]Cimbi-36 PET. The two-tissue compartment model using arterial input...

  12. PEROXISOME PROLIFERATOR-ACTIVATED RECEPTOR (PPAR) AGONISTS AS PROMISING NEW MEDICATIONS FOR DRUG ADDICTION: PRECLINICAL EVIDENCE

    Science.gov (United States)

    Foll, Bernard Le; Ciano, Patricia Di; Panlilio, Leigh V.; Goldberg, Steven R.; Ciccocioppo, Roberto

    2013-01-01

    This review examines the growing literature on the role of peroxisome proliferator-activated receptors (PPARs) in addiction. There are two subtypes of PPAR receptors that have been studied in addiction: PPAR-α and PPAR-γ. The role of each PPAR subtype in common models of addictive behavior, mainly pre-clinical models, is summarized. In particular, studies are reviewed that investigated the effects of PPAR-α agonists on relapse, sensitization, conditioned place preference, withdrawal and drug intake, and effects of PPAR-γ agonists on relapse, withdrawal and drug intake. Finally, studies that investigated the effects of PPAR agonists on neural pathways of addiction are reviewed. Taken together this preclinical data indicates that PPAR agonists are promising new medications for drug addiction treatment. PMID:23614675

  13. The effects of the dopamine agonist rotigotine on hemispatial neglect following stroke

    OpenAIRE

    Gorgoraptis, Nikos; Mah, Yee-Haur; Machner, Bjoern; Singh-Curry, Victoria; Malhotra, Paresh; Hadji-Michael, Maria; Cohen, David; Simister, Robert; Nair, Ajoy; Kulinskaya, Elena; Ward, Nick; Greenwood, Richard; Husain, Masud

    2012-01-01

    Hemispatial neglect following right-hemisphere stroke is a common and disabling disorder, for which there is currently no effective pharmacological treatment. Dopamine agonists have been shown to play a role in selective attention and working memory, two core cognitive components of neglect. Here, we investigated whether the dopamine agonist rotigotine would have a beneficial effect on hemispatial neglect in stroke patients. A double-blind, randomized, placebo-controlled ABA design was used, ...

  14. Do Agonistic Motives Matter More Than Anger? Three Studies of Cardiovascular Risk in Adolescents

    Science.gov (United States)

    Ewart, Craig K.; Elder, Gavin J.; Smyth, Joshua M.; Sliwinski, Martin J.; Jorgensen, Randall S.

    2011-01-01

    Objective Three motivational profiles have been associated with recurring psychological stress in low-income youth and young adults: Striving to control others (agonistic striving), striving to control the self (transcendence striving), and not asserting control (dissipated striving); Agonistic Striving has been associated with elevated ambulatory blood pressure during daily activities. Three studies tested the hypotheses that: (1) Agonistic Striving is associated with poor anger regulation, and (2) Agonistic Striving and poor anger regulation interactively elevate blood pressure. Design Motivational profiles, anger regulation, and ambulatory blood pressure were assessed in a multiethnic sample of 264 urban youth. Main outcome measures (1) Anger regulation/recovery during laboratory challenge; (2) anger / blood pressure during daily activities (48 hours). Results and conclusion Replication of the profiles in distant cities showed they occur with similar frequency across differences of region, race, and gender. Analyses controlling for body size, race, and gender revealed that individuals with the Agonistic Striving profile had higher ambulatory pressure, especially during social encounters. They became more openly angry and aggressive when challenged, but did not exhibit difficulty regulating anger in the laboratory, nor did they feel more angry during monitoring. However, individuals with the Agonistic Striving profile who did display poor anger regulation in the lab had the highest blood pressure; deficient self-regulatory capability amplified the positive association between Agonistic Striving and cardiovascular risk in both genders and all ethnic groups. Although anger is thought to increase cardiovascular risk, present findings suggest that anger and elevated blood pressure are co-effects of agonistic struggles to control others. PMID:21534673

  15. Airway Peroxidases Catalyze Nitration of the β2-Agonist Salbutamol and Decrease Its Pharmacological Activity

    OpenAIRE

    Reszka, Krzysztof J.; Sallans, Larry; Macha, Stephen; Brown, Kari; McGraw, Dennis W.; Kovacic, Melinda Butsch; Britigan, Bradley E.

    2011-01-01

    β2-Agonists are the most effective bronchodilators for the rapid relief of asthma symptoms, but for unclear reasons, their effectiveness may be decreased during severe exacerbations. Because peroxidase activity and nitrogen oxides are increased in the asthmatic airway, we examined whether salbutamol, a clinically important β2-agonist, is subject to potentially inactivating nitration. When salbutamol was exposed to myeloperoxidase, eosinophil peroxidase or lactoperoxidase in the presence of hy...

  16. Systematic review: cardiovascular safety profile of 5-HT(4) agonists developed for gastrointestinal disorders.

    Science.gov (United States)

    Tack, J; Camilleri, M; Chang, L; Chey, W D; Galligan, J J; Lacy, B E; Müller-Lissner, S; Quigley, E M M; Schuurkes, J; De Maeyer, J H; Stanghellini, V

    2012-04-01

    The nonselective 5-HT(4) receptor agonists, cisapride and tegaserod have been associated with cardiovascular adverse events (AEs). To perform a systematic review of the safety profile, particularly cardiovascular, of 5-HT(4) agonists developed for gastrointestinal disorders, and a nonsystematic summary of their pharmacology and clinical efficacy. Articles reporting data on cisapride, clebopride, prucalopride, mosapride, renzapride, tegaserod, TD-5108 (velusetrag) and ATI-7505 (naronapride) were identified through a systematic search of the Cochrane Library, Medline, Embase and Toxfile. Abstracts from UEGW 2006-2008 and DDW 2008-2010 were searched for these drug names, and pharmaceutical companies approached to provide unpublished data. Retrieved articles on pharmacokinetics, human pharmacodynamics and clinical data with these 5-HT(4) agonists, are reviewed and summarised nonsystematically. Articles relating to cardiac safety and tolerability of these agents, including any relevant case reports, are reported systematically. Two nonselective 5-HT(4) agonists had reports of cardiovascular AEs: cisapride (QT prolongation) and tegaserod (ischaemia). Interactions with, respectively, the hERG cardiac potassium channel and 5-HT(1) receptor subtypes have been suggested to account for these effects. No cardiovascular safety concerns were reported for the newer, selective 5-HT(4) agonists prucalopride, velusetrag, naronapride, or for nonselective 5-HT(4) agonists with no hERG or 5-HT(1) affinity (renzapride, clebopride, mosapride). 5-HT(4) agonists for GI disorders differ in chemical structure and selectivity for 5-HT(4) receptors. Selectivity for 5-HT(4) over non-5-HT(4) receptors may influence the agent's safety and overall risk-benefit profile. Based on available evidence, highly selective 5-HT(4) agonists may offer improved safety to treat patients with impaired GI motility. © 2012 Blackwell Publishing Ltd.

  17. Systematic review: cardiovascular safety profile of 5-HT4 agonists developed for gastrointestinal disorders

    OpenAIRE

    Tack, J; Camilleri, M; Chang, L; Chey, W D; Galligan, J J; Lacy, B E; Müller-Lissner, S; Quigley, E M M; Schuurkes, J; Maeyer, J H; Stanghellini, V

    2012-01-01

    Summary Background The nonselective 5-HT4 receptor agonists, cisapride and tegaserod have been associated with cardiovascular adverse events (AEs). Aim To perform a systematic review of the safety profile, particularly cardiovascular, of 5-HT4 agonists developed for gastrointestinal disorders, and a nonsystematic summary of their pharmacology and clinical efficacy. Methods Articles reporting data on cisapride, clebopride, prucalopride, mosapride, renzapride, tegaserod, TD-5108 (velusetrag) an...

  18. Systematic review: cardiovascular safety profile of 5-HT4 agonists developed for gastrointestinal disorders

    Science.gov (United States)

    Tack, J; Camilleri, M; Chang, L; Chey, W D; Galligan, J J; Lacy, B E; Müller-Lissner, S; Quigley, E M M; Schuurkes, J; Maeyer, J H; Stanghellini, V

    2012-01-01

    Summary Background The nonselective 5-HT4 receptor agonists, cisapride and tegaserod have been associated with cardiovascular adverse events (AEs). Aim To perform a systematic review of the safety profile, particularly cardiovascular, of 5-HT4 agonists developed for gastrointestinal disorders, and a nonsystematic summary of their pharmacology and clinical efficacy. Methods Articles reporting data on cisapride, clebopride, prucalopride, mosapride, renzapride, tegaserod, TD-5108 (velusetrag) and ATI-7505 (naronapride) were identified through a systematic search of the Cochrane Library, Medline, Embase and Toxfile. Abstracts from UEGW 2006–2008 and DDW 2008–2010 were searched for these drug names, and pharmaceutical companies approached to provide unpublished data. Results Retrieved articles on pharmacokinetics, human pharmacodynamics and clinical data with these 5-HT4 agonists, are reviewed and summarised nonsystematically. Articles relating to cardiac safety and tolerability of these agents, including any relevant case reports, are reported systematically. Two nonselective 5-HT4 agonists had reports of cardiovascular AEs: cisapride (QT prolongation) and tegaserod (ischaemia). Interactions with, respectively, the hERG cardiac potassium channel and 5-HT1 receptor subtypes have been suggested to account for these effects. No cardiovascular safety concerns were reported for the newer, selective 5-HT4 agonists prucalopride, velusetrag, naronapride, or for nonselective 5-HT4 agonists with no hERG or 5-HT1 affinity (renzapride, clebopride, mosapride). Conclusions 5-HT4 agonists for GI disorders differ in chemical structure and selectivity for 5-HT4 receptors. Selectivity for 5-HT4 over non-5-HT4 receptors may influence the agent's safety and overall risk–benefit profile. Based on available evidence, highly selective 5-HT4 agonists may offer improved safety to treat patients with impaired GI motility. PMID:22356640

  19. Optimisation of in silico derived 2-aminobenzimidazole hits as unprecedented selective kappa opioid receptor agonists

    DEFF Research Database (Denmark)

    Sasmal, Pradip K; Krishna, C Vamsee; Sudheerkumar Adabala, S

    2015-01-01

    Kappa opioid receptor (KOR) is an important mediator of pain signaling and it is targeted for the treatment of various pains. Pharmacophore based mining of databases led to the identification of 2-aminobenzimidazole derivative as KOR agonists with selectivity over the other opioid receptors DOR a...... of novel benzimidazole derivatives as KOR agonists are described. The in vivo proof of principle for anti-nociceptive effect with a lead compound from this series is exemplified....

  20. Evaluation of the Tolerability of Switching Patients on Chronic Full ?-Opioid Agonist Therapy to Buccal Buprenorphine

    OpenAIRE

    Webster, Lynn; Gruener, Daniel; Kirby, Todd; Xiang, Qinfang; Tzanis, Evan; Finn, Andrew

    2016-01-01

    Objective?Assess whether patients with chronic pain receiving 80 to 220?mg oral morphine sulfate equivalent of a full ?-opioid agonist could be transitioned to buccal buprenorphine at approximately 50% of their full dose without inducing opioid withdrawal or sacrificing analgesic efficacy. Methods.?A randomized, double-blind, double-dummy, active-controlled, two-period crossover study in adult patients receiving around-the-clock full opioid agonist therapy and confirmed to be opioid dependent...

  1. Discovery of Azetidinone Acids as Conformationally-Constrained Dual PPARalpha/gamma Agonists

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.; Devasthale, P; Farrelly, D; Gu, L; Harrity, T; Cap, M; Chu, C; Kunselman, L; Morgan, N; et. al.

    2008-01-01

    A novel class of azetidinone acid-derived dual PPAR{alpha}/{gamma} agonists has been synthesized for the treatment of diabetes and dyslipidemia. The preferred stereochemistry in this series for binding and functional agonist activity against both PPARa and PPAR? receptors was shown to be 3S,4S. Synthesis, in vitro and in vivo activities of compounds in this series are described. A high-yielding method for N-arylation of azetidinone esters is also described.

  2. Response of Peripheral Blood Lymphocytes from RAO-affected Horses to b2-Agonist Stimulation

    OpenAIRE

    Werner Becker, Marianne Patricia

    2011-01-01

    Recurrent airway obstruction (RAO) affects middle-age horses, inducing bronchoconstriction and airway inflammation. β2-agonists like salbutamol are used as treatment, promoting airway smooth muscle (ASM) relaxation and bronchodilation. In addition to ASM, inflammatory cells express the β2-adrenoreceptors (β2-AR). In other species, β2-agonists promote peripheral blood lymphocyte (PBL) cytokine expression towards a pro-inflammatory phenotype. RAO horses are a good model for evaluating chron...

  3. Targeted Delivery of LXR Agonist Using a Site-Specific Antibody-Drug Conjugate.

    Science.gov (United States)

    Lim, Reyna K V; Yu, Shan; Cheng, Bo; Li, Sijia; Kim, Nam-Jung; Cao, Yu; Chi, Victor; Kim, Ji Young; Chatterjee, Arnab K; Schultz, Peter G; Tremblay, Matthew S; Kazane, Stephanie A

    2015-11-18

    Liver X receptor (LXR) agonists have been explored as potential treatments for atherosclerosis and other diseases based on their ability to induce reverse cholesterol transport and suppress inflammation. However, this therapeutic potential has been hindered by on-target adverse effects in the liver mediated by excessive lipogenesis. Herein, we report a novel site-specific antibody-drug conjugate (ADC) that selectively delivers a LXR agonist to monocytes/macrophages while sparing hepatocytes. The unnatural amino acid para-acetylphenylalanine (pAcF) was site-specifically incorporated into anti-CD11a IgG, which binds the α-chain component of the lymphocyte function-associated antigen 1 (LFA-1) expressed on nearly all monocytes and macrophages. An aminooxy-modified LXR agonist was conjugated to anti-CD11a IgG through a stable, cathepsin B cleavable oxime linkage to afford a chemically defined ADC. The anti-CD11a IgG-LXR agonist ADC induced LXR activation specifically in human THP-1 monocyte/macrophage cells in vitro (EC50-27 nM), but had no significant effect in hepatocytes, indicating that payload delivery is CD11a-mediated. Moreover, the ADC exhibited higher-fold activation compared to a conventional synthetic LXR agonist T0901317 (Tularik) (3-fold). This novel ADC represents a fundamentally different strategy that uses tissue targeting to overcome the limitations of LXR agonists for potential use in treating atherosclerosis.

  4. The good, the bad, and the ugly: agonistic behaviour in juvenile crocodilians.

    Directory of Open Access Journals (Sweden)

    Matthew L Brien

    Full Text Available We examined agonistic behaviour in seven species of hatchling and juvenile crocodilians held in small groups (N = 4 under similar laboratory conditions. Agonistic interactions occurred in all seven species, typically involved two individuals, were short in duration (5-15 seconds, and occurred between 1600-2200 h in open water. The nature and extent of agonistic interactions, the behaviours displayed, and the level of conspecific tolerance varied among species. Discrete postures, non-contact and contact movements are described. Three of these were species-specific: push downs by C. johnstoni; inflated tail sweeping by C. novaeguineae; and, side head striking combined with tail wagging by C. porosus. The two long-snouted species (C. johnstoni and G. gangeticus avoided contact involving the head and often raised the head up out of the way during agonistic interactions. Several behaviours not associated with aggression are also described, including snout rubbing, raising the head up high while at rest, and the use of vocalizations. The two most aggressive species (C. porosus, C. novaeguineae appeared to form dominance hierarchies, whereas the less aggressive species did not. Interspecific differences in agonistic behaviour may reflect evolutionary divergence associated with morphology, ecology, general life history and responses to interspecific conflict in areas where multiple species have co-existed. Understanding species-specific traits in agonistic behaviour and social tolerance has implications for the controlled raising of different species of hatchlings for conservation, management or production purposes.

  5. Scaffold-based pan-agonist design for the PPARα, PPARβ and PPARγ receptors.

    Directory of Open Access Journals (Sweden)

    Li-Song Zhang

    Full Text Available As important members of nuclear receptor superfamily, Peroxisome proliferator-activated receptors (PPAR play essential roles in regulating cellular differentiation, development, metabolism, and tumorigenesis of higher organisms. The PPAR receptors have 3 identified subtypes: PPARα, PPARβ and PPARγ, all of which have been treated as attractive targets for developing drugs to treat type 2 diabetes. Due to the undesirable side-effects, many PPAR agonists including PPARα/γ and PPARβ/γ dual agonists are stopped by US FDA in the clinical trials. An alternative strategy is to design novel pan-agonist that can simultaneously activate PPARα, PPARβ and PPARγ. Under such an idea, in the current study we adopted the core hopping algorithm and glide docking procedure to generate 7 novel compounds based on a typical PPAR pan-agonist LY465608. It was observed by the docking procedures and molecular dynamics simulations that the compounds generated by the core hopping and glide docking not only possessed the similar functions as the original LY465608 compound to activate PPARα, PPARβ and PPARγ receptors, but also had more favorable conformation for binding to the PPAR receptors. The additional absorption, distribution, metabolism and excretion (ADME predictions showed that the 7 compounds (especially Cpd#1 hold high potential to be novel lead compounds for the PPAR pan-agonist. Our findings can provide a new strategy or useful insights for designing the effective pan-agonists against the type 2 diabetes.

  6. Effects of cannabinoid and vanilloid receptor agonists and their interaction on learning and memory in rats.

    Science.gov (United States)

    Shiri, Mariam; Komaki, Alireza; Oryan, Shahrbanoo; Taheri, Masoumeh; Komaki, Hamidreza; Etaee, Farshid

    2017-04-01

    Despite previous findings on the effects of cannabinoid and vanilloid systems on learning and memory, the effects of the combined stimulation of these 2 systems on learning and memory have not been studied. Therefore, in this study, we tested the interactive effects of cannabinoid and vanilloid systems on learning and memory in rats by using passive avoidance learning (PAL) tests. Forty male Wistar rats were divided into the following 4 groups: (1) control (DMSO+saline), (2) WIN55,212-2, (3) capsaicin, and (4) WIN55,212-2 + capsaicin. On test day, capsaicin, a vanilloid receptor type 1 (TRPV1) agonist, or WIN55,212-2, a cannabinoid receptor (CB 1 /CB 2 ) agonist, or both substances were injected intraperitoneally. Compared to the control group, the group treated with capsaicin (TRPV1 agonist) had better scores in the PAL acquisition and retention test, whereas treatment with WIN55,212-2 (CB 1 /CB 2 agonist) decreased the test scores. Capsaicin partly reduced the effects of WIN55,212-2 on PAL and memory. We conclude that the acute administration of a TRPV1 agonist improves the rats' cognitive performance in PAL tasks and that a vanilloid-related mechanism may underlie the agonistic effect of WIN55,212-2 on learning and memory.

  7. PPARα-Independent Arterial Smooth Muscle Relaxant Effects of PPARα Agonists

    Directory of Open Access Journals (Sweden)

    Neerupma Silswal

    2012-01-01

    Full Text Available We sought to determine direct vascular effects of peroxisome proliferator-activated receptor alpha (PPARα agonists using isolated mouse aortas and middle cerebral arteries (MCAs. The PPARα agonists GW7647, WY14643, and gemfibrozil acutely relaxed aortas held under isometric tension and dilated pressurized MCAs with the following order of potency: GW7647≫WY14643>gemfibrozil. Responses were endothelium-independent, and the use of PPARα deficient mice demonstrated that responses were also PPARα-independent. Pretreating arteries with high extracellular K+ attenuated PPARα agonist-mediated relaxations in the aorta, but not in the MCA. In the aorta, the ATP sensitive potassium (KATP channel blocker glibenclamide also impaired relaxations whereas the other K+ channel inhibitors, 4-aminopyridine and Iberiotoxin, had no effect. In aortas, GW7647 and WY14643 elevated cGMP levels by stimulating soluble guanylyl cyclase (sGC, and inhibition of sGC with ODQ blunted relaxations to PPARα agonists. In the MCA, dilations were inhibited by the protein kinase C (PKC activator, phorbol 12,13-dibutyrate, and also by ODQ. Our results demonstrated acute, nonreceptor-mediated relaxant effects of PPARα agonists on smooth muscle of mouse arteries. Responses to PPARα agonists in the aorta involved KATP channels and sGC, whereas in the MCA the PKC and sGC pathways also appeared to contribute to the response.

  8. Reconstitution of high affinity α2 adrenergic agonist binding by fusion with a pertussis toxin substrate

    International Nuclear Information System (INIS)

    Kim, M.H.; Neubig, R.R.

    1986-01-01

    High affinity α 2 adrenergic agonist binding is thought to occur via a coupling of the α 2 receptor with N/sub i/, the inhibitory guanyl nucleotide binding protein. Human platelet membranes pretreated at pH 11.5 exhibit a selective inactivation of agonist binding and N/sub i/. To further study the mechanism of agonist binding, alkali treated membranes (ATM) were mixed with membranes pretreated with 10 μM phenoxybenzamine to block α 2 receptors (POB-M). The combined membrane pellet was incubated in 50% polyethylene glycol (PEG) to promote membrane-membrane fusion and assayed for binding to the α 2 agonist [ 3 H]UK 14,304 (UK) and the antagonist [ 3 H] yohimbine. PEG treatment resulted in a 2-4 fold enhancement of UK binding whereas yohimbine binding was unchanged. No enhancement of UK binding was observed in the absence of PEG treatment. The reconstitution was dependent on the addition of POB-M. They found that a 1:1 ratio of POB-M:ATM was optimal. Reconstituted binding was inhibited by GppNHp. Fusion of rat C6 glioma cell membranes, which do not contain α 2 receptors, also enhanced agonist binding to ATM. Fusion of C6 membranes from cells treated with pertussis toxin did not enhance [ 3 H] UK binding. These data show that a pertussis toxin sensitive membrane component, possibly N/sub i/, can reconstitute high affinity α 2 agonist binding

  9. Generalized concentration addition: a method for examining mixtures containing partial agonists.

    Science.gov (United States)

    Howard, Gregory J; Webster, Thomas F

    2009-08-07

    Environmentally relevant toxic exposures often consist of simultaneous exposure to multiple agents. Methods to predict the expected outcome of such combinations are critical both to risk assessment and to an accurate judgment of whether combinations are synergistic or antagonistic. Concentration addition (CA) has commonly been used to assess the presence of synergy or antagonism in combinations of similarly acting chemicals, and to predict effects of combinations of such agents. CA has the advantage of clear graphical interpretation: Curves of constant joint effect (isoboles) must be negatively sloped straight lines if the mixture is concentration additive. However, CA cannot be directly used to assess combinations that include partial agonists, although such agents are of considerable interest. Here, we propose a natural extension of CA to a functional form that may be applied to mixtures including full agonists and partial agonists. This extended definition, for which we suggest the term "generalized concentration addition," encompasses linear isoboles with slopes of any sign. We apply this approach to the simple example of agents with dose-response relationships described by Hill functions with slope parameter n=1. The resulting isoboles are in all cases linear, with negative, zero and positive slopes. Using simple mechanistic models of ligand-receptor systems, we show that the same isobole pattern and joint effects are generated by modeled combinations of full and partial agonists. Special cases include combinations of two full agonists and a full agonist plus a competitive antagonist.

  10. Radiolabelled D2 agonists as prolactinoma imaging agents

    Energy Technology Data Exchange (ETDEWEB)

    Otto, C.A.

    1989-08-01

    During the past year, further studies on mAChR were conducted. These studies included verification of the difference in pituitary distribution based on ligand charge. The pituitary localization of TRB. A neutral mAChR ligand, was verified. The lack of QNB blockade of TRB uptake was tested by blockage with scopolamine, another mAChR antagonist and by testing the effect in a different strain of rat. Neither scopolamine or change of rat strain had any effect. We concluded that TRB uptake in pituitary is not a receptor-mediated process. Further studies were conducted with an additional quaternized mAChR ligand: MQNB. Pituitary localization of MQNB, like MTRB, could be blocked by pretreatment with QNB. We have tentatively concluded that permanent charge on a mAChR antagonist changes the mechanism of uptake in the pituitary. Time course studies and the effects of DES on myocardial uptake are reported. A brief report on preliminary results of evaluation of quaternized mAChR ligands in the heart is included. In a limited series of such ligands, we have observed a single binding site and a difference in B{sub max} values: QNB competition studies yield larger B{sub max} values than studies with {sup 3}H-NMS. Progress in the synthesis of D{sub 2} agonists includes solving a synthetic problem and preparation of the cold'' analogue of N-0437 using procedures applicable to eventual synthesis with {sup 11}C-CH{sub 3}I. 2 refs., 5 figs., 1 tab.

  11. Transcriptome analysis of endometrial tissues following GnRH agonist treatment in a mouse adenomyosis model

    Directory of Open Access Journals (Sweden)

    Guo S

    2017-03-01

    Full Text Available Song Guo,1,* Xiaowei Lu,1,* Ruihuan Gu,2 Di Zhang,3 Yijuan Sun,2 Yun Feng1 1Department of Obstetrics and Gynecology, Reproductive Medicine Center, Ruijin Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, People’s Republic of China; 2Gynecology, Shanghai Ji Ai Genetics & In Vitro Fertilization Institute, Obstetrics and Gynecology Hospital, Fudan University, Shanghai, People’s Republic of China; 3Department of Gynecology and Obstetrics, Jinan Military General Hospital, Jinan, People’s Republic of China *These authors contributed equally to this work Purpose: Adenomyosis is a common, benign gynecological condition of the female reproductive tract characterized by heavy menstrual bleeding and dysmenorrhea. Gonadotropin-releasing hormone (GnRH agonists are one of the medications used in adenomyosis treatment; however, their underlying mechanisms are poorly understood. Moreover, it is difficult to obtain endometrial samples from women undergoing such treatment. To overcome this, we generated an adenomyosis mouse model, which we treated with an GnRH agonist to determine its effect on pregnancy outcomes. We also analyzed endometrial gene expression following GnRH agonist treatment to determine the mechanisms that may affect pregnancy outcome in individuals with adenomyosis.Methods: Neonatal female mice were divided into a control group, an untreated adenomyosis group, and an adenomyosis group treated with a GnRH agonist (n=6 each. The pregnancy outcome was observed and compared among the groups. Then, three randomly chosen transcriptomes from endometrial tissues from day 4 of pregnancy were analyzed between the adenomyosis group and the GnRH agonist treatment group by RNA sequencing and quantitative reverse transcription polymerase chain reaction (PCR.Results: The litter size was significantly smaller in the adenomyosis group than in the control group (7±0.28 vs 11±0.26; P<0.05. However, the average live litter

  12. Imidazopyridine CB2 agonists: optimization of CB2/CB1 selectivity and implications for in vivo analgesic efficacy.

    Science.gov (United States)

    Trotter, B Wesley; Nanda, Kausik K; Burgey, Christopher S; Potteiger, Craig M; Deng, James Z; Green, Ahren I; Hartnett, John C; Kett, Nathan R; Wu, Zhicai; Henze, Darrell A; Della Penna, Kimberly; Desai, Reshma; Leitl, Michael D; Lemaire, Wei; White, Rebecca B; Yeh, Suzie; Urban, Mark O; Kane, Stefanie A; Hartman, George D; Bilodeau, Mark T

    2011-04-15

    A new series of imidazopyridine CB2 agonists is described. Structural optimization improved CB2/CB1 selectivity in this series and conferred physical properties that facilitated high in vivo exposure, both centrally and peripherally. Administration of a highly selective CB2 agonist in a rat model of analgesia was ineffective despite substantial CNS exposure, while administration of a moderately selective CB2/CB1 agonist exhibited significant analgesic effects. Copyright © 2011 Elsevier Ltd. All rights reserved.

  13. Farnesoid X receptor induces Takeda G-protein receptor 5 cross-talk to regulate bile acid synthesis and hepatic metabolism.

    Science.gov (United States)

    Pathak, Preeti; Liu, Hailiang; Boehme, Shannon; Xie, Cen; Krausz, Kristopher W; Gonzalez, Frank; Chiang, John Y L

    2017-06-30

    The bile acid-activated receptors, nuclear farnesoid X receptor (FXR) and the membrane Takeda G-protein receptor 5 (TGR5), are known to improve glucose and insulin sensitivity in obese and diabetic mice. However, the metabolic roles of these two receptors and the underlying mechanisms are incompletely understood. Here, we studied the effects of the dual FXR and TGR5 agonist INT-767 on hepatic bile acid synthesis and intestinal secretion of glucagon-like peptide-1 (GLP-1) in wild-type, Fxr -/- , and Tgr5 -/- mice. INT-767 efficaciously stimulated intracellular Ca 2+ levels, cAMP activity, and GLP-1 secretion and improved glucose and lipid metabolism more than did the FXR-selective obeticholic acid and TGR5-selective INT-777 agonists. Interestingly, INT-767 reduced expression of the genes in the classic bile acid synthesis pathway but induced those in the alternative pathway, which is consistent with decreased taurocholic acid and increased tauromuricholic acids in bile. Furthermore, FXR activation induced expression of FXR target genes, including fibroblast growth factor 15, and unexpectedly Tgr5 and prohormone convertase 1/3 gene expression in the ileum. We identified an FXR-responsive element on the Tgr5 gene promoter. Fxr -/- and Tgr5 -/- mice exhibited reduced GLP-1 secretion, which was stimulated by INT-767 in the Tgr5 -/- mice but not in the Fxr -/- mice. Our findings uncovered a novel mechanism in which INT-767 activation of FXR induces Tgr5 gene expression and increases Ca 2+ levels and cAMP activity to stimulate GLP-1 secretion and improve hepatic glucose and lipid metabolism in high-fat diet-induced obese mice. Activation of both FXR and TGR5 may therefore represent an effective therapy for managing hepatic steatosis, obesity, and diabetes. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  14. Reconstitution of high-affinity opioid agonist binding in brain membranes

    Energy Technology Data Exchange (ETDEWEB)

    Remmers, A.E.; Medzihradsky, F. (Univ. of Michigan Medical School, Ann Arbor (United States))

    1991-03-15

    In synaptosomal membranes from rat brain cortex, the {mu} selective agonist ({sup 3}H)dihydromorphine in the absence of sodium, and the nonselective antagonist ({sup 3}H)naltrexone in the presence of sodium, bound to two populations of opioid receptor sites with K{sub d} values of 0.69 and 8.7 nM for dihydromorphine, and 0.34 and 5.5 nM for naltrexone. The addition of 5 {mu}M guanosine 5{prime}-({gamma}-thio)triphosphate (GTP({gamma}S)) strongly reduced high-affinity agonist but not antagonist binding. Exposure of the membranes to high pH reduced the number of GTP({gamma}-{sup 35}S) binding sites by 90% and low K{sub m}, opioid-sensitive GTPase activity by 95%. In these membranes, high-affinity agonist binding was abolished and modulation of residual binding by GTP({gamma}S) was diminished. Alkali treatment of the glioma cell membranes prior to fusion inhibited most of the low K{sub m} GTPase activity and prevented the reconstitution of agonist binding. The results show that high-affinity opioid agonist binding reflects the ligand-occupied receptor - guanine nucleotide binding protein complex.

  15. Clinical significance of suboptimal hormonal levels in men with prostate cancer treated with LHRH agonists.

    Science.gov (United States)

    Kawakami, Jun; Morales, Alvaro

    2013-01-01

    We examined the serum levels of testosterone (T) (total and bioavailable) dehydroepiandrosterone (DHEA), follicle-stimulating hormone (FSH), luteinizing hormone (LH), and prostate-specific antigen (PSA) in men receiving treatment with luteinizing hormone releasing-hormone (LHRH) agonists for metastatic prostate cancer. In doing this, we want to determine the efficacy of these agents in lowering T levels and whether a possible relationship exists between PSA values, as a surrogate measure of tumour activity, and hormone levels. This was a single centre prospective study of patients on LHRH agonists. Of all the 100 eligible patients, 31 did not qualify (10 were receiving their first injection, 13 were on intermittent hormonal therapy, 7 refused to enter the trial and 1 patient's blood sample was lost). Therefore in total, 69 patients were included in the final analysis. Each patient had their blood sample drawn immediately before the administration of a LHRH agonist. The new proposed criteria of values are more commonly found in patients with suboptimal levels of testosterone receiving LHRH analogs, but the clinical importance of this finding has not been established. There is no significant difference with respect to hormonal levels reached among patients on a variety of LHRH agonists. Total testosterone determinations should be considered in patients on LHRH agonist therapy, particularly when the PSA values begin to rise since it may lead to further beneficial hormonal manipulation.

  16. Identification of adiponectin receptor agonist utilizing a fluorescence polarization based high throughput assay.

    Directory of Open Access Journals (Sweden)

    Yiyi Sun

    Full Text Available Adiponectin, the adipose-derived hormone, plays an important role in the suppression of metabolic disorders that can result in type 2 diabetes, obesity, and atherosclerosis. It has been shown that up-regulation of adiponectin or adiponectin receptor has a number of therapeutic benefits. Given that it is hard to convert the full size adiponectin protein into a viable drug, adiponectin receptor agonists could be designed or identified using high-throughput screening. Here, we report on the development of a two-step screening process to identify adiponectin agonists. First step, we developed a high throughput screening assay based on fluorescence polarization to identify adiponectin ligands. The fluorescence polarization assay reported here could be adapted to screening against larger small molecular compound libraries. A natural product library containing 10,000 compounds was screened and 9 hits were selected for validation. These compounds have been taken for the second-step in vitro tests to confirm their agonistic activity. The most active adiponectin receptor 1 agonists are matairesinol, arctiin, (--arctigenin and gramine. The most active adiponectin receptor 2 agonists are parthenolide, taxifoliol, deoxyschizandrin, and syringin. These compounds may be useful drug candidates for hypoadiponectin related diseases.

  17. Rat Urinary Bladder Carcinogenesis by Dual-Acting PPARα+γ Agonists

    Directory of Open Access Journals (Sweden)

    Martin B. Oleksiewicz

    2008-01-01

    Full Text Available Despite clinical promise, dual-acting activators of PPARα and γ (here termed PPARα+γ agonists have experienced high attrition rates in preclinical and early clinical development, due to toxicity. In some cases, discontinuation was due to carcinogenic effect in the rat urothelium, the epithelial layer lining the urinary bladder, ureters, and kidney pelvis. Chronic pharmacological activation of PPARα is invariably associated with cancer in rats and mice. Chronic pharmacological activation of PPARγ can in some cases also cause cancer in rats and mice. Urothelial cells coexpress PPARα as well as PPARγ, making it plausible that the urothelial carcinogenicity of PPARα+γ agonists may be caused by receptor-mediated effects (exaggerated pharmacology. Based on previously published mode of action data for the PPARα+γ agonist ragaglitazar, and the available literature about the role of PPARα and γ in rodent carcinogenesis, we propose a mode of action hypothesis for the carcinogenic effect of PPARα+γ agonists in the rat urothelium, which combines receptor-mediated and off-target cytotoxic effects. The proposed mode of action hypothesis is being explored in our laboratories, towards understanding the human relevance of the rat cancer findings, and developing rapid in vitro or short-term in vivo screening approaches to faciliate development of new dual-acting PPAR agonist compounds.

  18. Combined sodium ion sensitivity in agonist binding and internalization of vasopressin V1b receptors.

    Science.gov (United States)

    Koshimizu, Taka-Aki; Kashiwazaki, Aki; Taniguchi, Junichi

    2016-05-03

    Reducing Na(+) in the extracellular environment may lead to two beneficial effects for increasing agonist binding to cell surface G-protein coupled receptors (GPCRs): reduction of Na(+)-mediated binding block and reduce of receptor internalization. However, such combined effects have not been explored. We used Chinese Hamster Ovary cells expressing vasopressin V1b receptors as a model to explore Na(+) sensitivity in agonist binding and receptor internalization. Under basal conditions, a large fraction of V1b receptors is located intracellularly, and a small fraction is in the plasma membrane. Decreases in external Na(+) increased cell surface [(3)H]AVP binding and decreased receptor internalization. Substitution of Na(+) by Cs(+) or NH4(+) inhibited agonist binding. To suppress receptor internalization, the concentration of NaCl, but not of CsCl, had to be less than 50 mM, due to the high sensitivity of the internalization machinery to Na(+) over Cs(+). Iso-osmotic supplementation of glucose or NH4Cl maintained internalization of the V1b receptor, even in a low-NaCl environment. Moreover, iodide ions, which acted as a counter anion, inhibited V1b agonist binding. In summary, we found external ionic conditions that could increase the presence of high-affinity state receptors at the cell surface with minimum internalization during agonist stimulations.

  19. Potential of beta-adrenergic agonists for increasing protein deposition in ruminants in developing countries

    International Nuclear Information System (INIS)

    Berschauer, F.

    1989-01-01

    Various substituted phenylethanolamines, acting on the sympathetic nervous system, have been shown to increase protein retention (via decreased proteolysis) and reduce fat deposition (via increased lipolysis and reduced lipogenesis) in ruminants and monogastrics. Research with finishing lambs in developed countries show various beta-adrenergic agonists to improve growth rate (by 18%), feed conversion (by 12%) and carcass quality (28% increase in area of longissimus dorsi and 33% reduction in subcutaneous fat). Similar effects of beta-agonists on carcass composition of well fed cattle have been reported. The effects of beta-agonists on livestock in developing countries of the tropics have not yet been investigated, but their effects in increasing metabolic rate suggest that treated ruminants would be more vulnerable to hot environments. Beta-agonists appear to improve nitrogen retention to a greater extent in breeds with a lower potential for muscle growth. In view of this, they might be particularly effective in improving nitrogen retention in tropical breeds which have a low growth potential. This aspect, together with the response of undernourished animals in the developing countries, needs investigation. Beta-adrenergic agonists are not yet registered for use in animal production, but product licenses for some of them are expected to be granted soon. (author). 31 refs, 1 fig., 12 tabs

  20. Detection of glucocorticoid receptor agonists in effluents from sewage treatment plants in Japan.

    Science.gov (United States)

    Suzuki, Go; Sato, Kentaro; Isobe, Tomohiko; Takigami, Hidetaka; Brouwer, Abraham; Nakayama, Kei

    2015-09-15

    Glucocorticoids (GCs) are widely used as anti-inflammatory drugs. Our previous study demonstrated that several GCs such as cortisol and dexamethasone (Dex) were frequently detected in effluents collected from Japanese sewage treatment plants (STPs) in 2012. In this study, we used the GC-Responsive Chemical-Activated LUciferase gene eXpression (GR-CALUX) assay to elucidate GC receptor (GR) agonistic activities of ten pure synthetic GCs and selected STP effluents in Japan for assessment of the risks associated with the presence of GR agonists. The tested GCs demonstrated dose-dependent agonistic effects in the GR-CALUX assay and their EC50 values were calculated for estimation of relative potencies (REPs) compared to Dex. The GR agonistic potency was in the rank of: clobetasol propionate > clobetasone butyrate > betamethasone 17-valerate > difluprednate > betamethasone 17,21-dipropionate > Dex > betamethasone > 6α-methylprednisolone > prednisolone > cortisol. The GR agonistic activity in STP effluents as measured in Dex-equivalent (Dex-EQ) activities ranged from effluents in Japan. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Identification of novel selective V2 receptor non-peptide agonists.

    Science.gov (United States)

    Del Tredici, Andria L; Vanover, Kim E; Knapp, Anne E; Bertozzi, Sine M; Nash, Norman R; Burstein, Ethan S; Lameh, Jelveh; Currier, Erika A; Davis, Robert E; Brann, Mark R; Mohell, Nina; Olsson, Roger; Piu, Fabrice

    2008-10-30

    Peptides with agonist activity at the vasopressin V(2) receptor are used clinically to treat fluid homeostasis disorders such as polyuria and central diabetes insipidus. Of these peptides, the most commonly used is desmopressin, which displays poor bioavailability as well as potent activity at the V(1b) receptor, with possible stress-related adverse effects. Thus, there is a strong need for the development of small molecule chemistries with selective V(2) receptor agonist activity. Using the functional cell-based assay Receptor Selection and Amplification Technology (R-SAT((R))), a screening effort identified three small molecule chemotypes (AC-94544, AC-88324, and AC-110484) with selective agonist activity at the V(2) receptor. One of these compounds, AC-94544, displayed over 180-fold selectivity at the V(2) receptor compared to related vasopressin and oxytocin receptors and no activity at 28 other G protein-coupled receptors (GPCRs). All three compounds also showed partial agonist activity at the V(2) receptor in a cAMP accumulation assay. In addition, in a rat model of central diabetes insipidus, AC-94544 was able to significantly reduce urine output in a dose-dependent manner. Thus, AC-94544, AC-88324, and AC-110484 represent novel opportunities for the treatment of disorders associated with V(2) receptor agonist deficiency.

  2. Agonist-induced desensitization of adenylyl cyclase in Y1 adrenocortical tumor cells

    International Nuclear Information System (INIS)

    Olson, M.F.; Tsao, J.; Pon, D.J.; Schimmer, B.P.

    1991-01-01

    Y1 adrenocortical tumor cells (Y1DS) and Y1 mutants resistant to ACTH-induced desensitization of adenylyl cyclase (Y1DR) were transfected with a gene encoding the mouse beta 2-adrenergic receptor (beta 2-AR). Transfectants expressed beta 2-ARs that were able to stimulate adenylyl cyclase activity and steroid biosynthesis. These transfectants were used to explore the basis for the DR mutation in Y1 cells. The authors demonstrate that beta-adrenergic agonists desensitize the adenylyl cyclase system in transfected Y1DS cells whereas transfected Y1DR cells are resistant to desensitization by beta-adrenergic agonists. The fate of the beta 2-ARs during desensitization was evaluated by photoaffinity labelling with [125I]iodocyanopindolol diazerine. Desensitization of Y1DS transfectants was accompanied by a modest loss in receptor density that was insufficient to account for the complete loss of responsiveness to beta-adrenergic agonists. The extent of receptor loss induced by beta-adrenergic agonists in Y1DR transfectants exceeded that in the Y1DS transfectants indicating that the mutation which protects Y1DR cells from agonist-induced desensitization is prior to receptor down-regulation in the desensitization pathway. From these results we infer that ACTH and isoproterenol desensitize adenylyl cyclase by a common pathway and that receptor loss is not a major component of the desensitization process in these cells

  3. The therapeutic potential of nicotinic acetylcholine receptor agonists for pain control.

    Science.gov (United States)

    Decker, M W; Meyer, M D; Sullivan, J P

    2001-10-01

    Due to the limitations of currently available analgesics, a number of novel alternatives are currently under investigation, including neuronal nicotinic acetylcholine receptor (nAChR) agonists. During the 1990s, the discovery of the antinociceptive properties of the potent nAChR agonist epibatidine in rodents sparked interest in the analgesic potential of this class of compounds. Although epibatidine also has several mechanism-related toxicities, the identification of considerable nAChR diversity suggested that the toxicities and therapeutic actions of the compound might be mediated by distinct receptor subtypes. Consistent with this view, a number of novel nAChR agonists with antinociceptive activity and improved safety profiles in preclinical models have now been identified, including A-85380, ABT-594, DBO-83, SIB-1663 and RJR-2403. Of these, ABT-594 is the most advanced and is currently in Phase II clinical evaluation. Nicotinically-mediated antinociception has been demonstrated in a variety of rodent pain models and is likely mediated by the activation of descending inhibitory pathways originating in the brainstem with the predominant high-affinity nicotine site in brain, the alpha4beta2 subtype, playing a critical role. Thus, preclinical findings suggest that nAChR agonists have the potential to be highly efficacious treatments in a variety of pain states. However, clinical proof-of-principle studies will be required to determine if nAChR agonists are active in pathological pain.

  4. Xamoterol, a new selective beta-1-adrenoceptor partial agonist, in the treatment of postural hypotension

    DEFF Research Database (Denmark)

    Mehlsen, J; Trap-Jensen, J

    1986-01-01

    Three patients severely disabled from postural hypotension were treated with xamoterol, a selective beta-1-adrenoceptor antagonist with a high degree of partial agonist activity. Oral treatment (200 mg b.i.d.) was chosen on the basis of the effects of acute intravenous administration of xamoterol...... and pindolol, a non-selective beta-adrenoceptor antagonist with partial agonist activity. In these patients pindolol had a predominantly antagonist effect, whereas xamoterol had a predominantly agonist effect after intravenous administration. Oral treatment was carried out with placebo control in a single......, supine). During the placebo period (2 weeks) heart rate decreased to pretreatment levels and mean blood pressure was reduced by only 14 mmHg. The patients reported substantial improvement in their condition during active medication. Xamoterol seems to be a useful alternative in the treatment of postural...

  5. PPARα agonists up-regulate organic cation transporters in rat liver cells

    International Nuclear Information System (INIS)

    Luci, Sebastian; Geissler, Stefanie; Koenig, Bettina; Koch, Alexander; Stangl, Gabriele I.; Hirche, Frank; Eder, Klaus

    2006-01-01

    It has been shown that clofibrate treatment increases the carnitine concentration in the liver of rats. However, the molecular mechanism is still unknown. In this study, we observed for the first time that treatment of rats with the peroxisome proliferator activated receptor (PPAR)-α agonist clofibrate increases hepatic mRNA concentrations of organic cation transporters (OCTNs)-1 and -2 which act as transporters of carnitine into the cell. In rat hepatoma (Fao) cells, treatment with WY-14,643 also increased the mRNA concentration of OCTN-2. mRNA concentrations of enzymes involved in carnitine biosynthesis were not altered by treatment with the PPARα agonists in livers of rats and in Fao cells. We conclude that PPARα agonists increase carnitine concentrations in livers of rats and cells by an increased uptake of carnitine into the cell but not by an increased carnitine biosynthesis

  6. Protective effects of the angiotensin II ATreceptor agonist compound 21 in ischemic stroke

    DEFF Research Database (Denmark)

    Bennion, Douglas M; Jones, Chad H; Dang, Alex N

    2018-01-01

    ) and systemic administration, are unsuitable for translation into humans; in the latter case because AT2receptor agonists are blood-brain barrier (BBB) impermeable. To circumvent this problem, in the current study we utilized the nose-to-brain (N2B) route of administration to bypass the BBB and deliver...... in certain human central nervous system diseases, the N2B application of AT2receptor agonists may become a viable mode of delivering these neuroprotective agents for human ischemic stroke patients.......-administered C21 did not affect blood pressure or heart rate. Thus, these data provide proof-of-principle for the idea that N2B application of an AT2receptor agonist can exert neuroprotective actions when administered following ischemic stroke. Since N2B delivery of other agents has been shown to be effective...

  7. A novel nicotinic agonist facilitates induction of long-term potentiation in the rat hippocampus.

    Science.gov (United States)

    Hunter, B E; de Fiebre, C M; Papke, R L; Kem, W R; Meyer, E M

    1994-02-28

    Long-term potentiation (LTP) can be modulated by a number of neurotransmitter receptors including muscarinic and GABAergic receptor types. We have found that a novel nicotinic agonist, 2,4-dimethoxybenzylidene anabaseine (DMXB), facilitated the induction of LTP in the hippocampus in a dose-dependent and mecamylamine-sensitive manner. DMXB displaced high affinity nicotinic [125I]alpha-bungarotoxin and [3H]acetylcholine binding in rat brain. Xenopus oocyte studies demonstrated that DMXB has agonist activity at alpha 7 but not alpha 4/beta 2 nicotinic receptor subtypes. These results indicated that DMXB is a novel nicotinic agonist with apparent specificity for the alpha 7/alpha-bungarotoxin nicotinic receptor subtype and indicate that nicotinic receptor activation is capable of modulating the induction of long-term potentiation.

  8. Assembly of high-affinity insulin receptor agonists and antagonists from peptide building blocks

    Science.gov (United States)

    Schäffer, Lauge; Brissette, Renee E.; Spetzler, Jane C.; Pillutla, Renuka C.; Østergaard, Søren; Lennick, Michael; Brandt, Jakob; Fletcher, Paul W.; Danielsen, Gillian M.; Hsiao, Ku-Chuan; Andersen, Asser S.; Dedova, Olga; Ribel, Ulla; Hoeg-Jensen, Thomas; Hansen, Per Hertz; Blume, Arthur J.; Markussen, Jan; Goldstein, Neil I.

    2003-01-01

    Insulin is thought to elicit its effects by crosslinking the two extracellular α-subunits of its receptor, thereby inducing a conformational change in the receptor, which activates the intracellular tyrosine kinase signaling cascade. Previously we identified a series of peptides binding to two discrete hotspots on the insulin receptor. Here we show that covalent linkage of such peptides into homodimers or heterodimers results in insulin agonists or antagonists, depending on how the peptides are linked. An optimized agonist has been shown, both in vitro and in vivo, to have a potency close to that of insulin itself. The ability to construct such peptide derivatives may offer a path for developing agonists or antagonists for treatment of a wide variety of diseases. PMID:12684539

  9. ''Spare'' alpha 1-adrenergic receptors and the potency of agonists in rat vas deferens

    International Nuclear Information System (INIS)

    Minneman, K.P.; Abel, P.W.

    1984-01-01

    The existence of ''spare'' alpha 1-adrenergic receptors in rat vas deferens was examined directly using radioligand binding assays and contractility measurements. Alpha 1-adrenergic receptors in homogenates of rat vas deferens were labeled with [ 125 I]BE 2254 ( 125 IBE). Norepinephrine and other full alpha 1-adrenergic receptor agonists were much less potent in inhibiting 125 IBE binding than in contracting the vas deferens in vitro. Treatment with 300 nM phenoxybenzamine for 10 min to irreversibly inactivate alpha 1-adrenergic receptors caused a large decrease in the potency of full agonists in causing contraction of this tissue and a 23-48% decrease in the maximal contraction observed. Using those data, equilibrium constants for activation (Kact values) of the receptors by agonists were calculated. These Kact values agreed well with the equilibrium binding constants (KD values) determined from displacement of 125 IBE binding. The reduction in alpha 1-adrenergic receptor density following phenoxybenzamine treatment was determined by Scatchard analysis of specific 125 IBE binding sites and compared with the expected reduction (q values) calculated from the agonist dose-response curves before and after phenoxybenzamine treatment. This suggests that phenoxybenzamine functionally inactivates alpha 1-adrenergic receptors at or near the receptor binding site. These experiments suggest that the potencies of agonists in activating alpha 1-adrenergic receptors in rat vas deferens agree well with their potencies in binding to the receptors. The greater potency of agonists in causing contraction may be due to spare receptors in this tissue. The data also demonstrate that phenoxybenzamine irreversibly inactivates alpha 1-adrenergic receptors in rat vas deferens, but that the decrease in receptor density is much smaller than that predicted from receptor theory

  10. Development of CINPA1 analogs as novel and potent inverse agonists of constitutive androstane receptor.

    Science.gov (United States)

    Lin, Wenwei; Yang, Lei; Chai, Sergio C; Lu, Yan; Chen, Taosheng

    2016-01-27

    Constitutive androstane receptor (CAR, NR1I3) and pregnane X receptor (PXR, NR1I2) are master regulators of endobiotic and xenobiotic metabolism and disposition. Because CAR is constitutively active in certain cellular contexts, inhibiting CAR might reduce drug-induced hepatotoxicity and resensitize drug-resistant cancer cells to chemotherapeutic drugs. We recently reported a novel CAR inhibitor/inverse agonist CINPA1 (11). Here, we have obtained or designed 54 analogs of CINPA1 and used a time-resolved fluorescence resonance energy transfer (TR-FRET) assay to evaluate their CAR inhibition potency. Many of the 54 analogs showed CAR inverse agonistic activities higher than those of CINPA1, which has an IC50 value of 687 nM. Among them, 72 has an IC50 value of 11.7 nM, which is about 59-fold more potent than CINPA1 and over 10-fold more potent than clotrimazole (an IC50 value of 126.9 nM), the most potent CAR inverse agonist in a biochemical assay previously reported by others. Docking studies provide a molecular explanation of the structure-activity relationship (SAR) observed experimentally. To our knowledge, this effort is the first chemistry endeavor in designing and identifying potent CAR inverse agonists based on a novel chemical scaffold, leading to 72 as the most potent CAR inverse agonist so far. The 54 chemicals presented are novel and unique tools for characterizing CAR's function, and the SAR information gained from these 54 analogs could guide future efforts to develop improved CAR inverse agonists. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

  11. Overcoming beta-agonist tolerance: high dose salbutamol and ipratropium bromide. Two randomised controlled trials

    Directory of Open Access Journals (Sweden)

    Haney Sarah

    2007-03-01

    Full Text Available Abstract Background Asthmatics treated with long-acting beta-agonists have a reduced bronchodilator response to moderate doses of inhaled short acting beta-agonists during acute bronchoconstriction. It is not known if the response to higher doses of nebulised beta-agonists or other bronchodilators is impaired. We assessed the effect of long-acting beta-agonist treatment on the response to 5 mg nebulised salbutamol and to ipratropium bromide. Methods Two double-blind, placebo-controlled, crossover studies of inhaled formoterol 12 μg twice daily in patients with asthma. High-dose salbutamol: 36 hours after the last dose of 1 week of formoterol or placebo treatment, 11 subjects inhaled methacholine to produce a 20% fall in FEV1. Salbutamol 5 mg was then administered via nebuliser and the FEV1 was monitored for 20 minutes. Ipratropium: 36 hours after the last dose of 1 week of formoterol or placebo treatment, 11 subjects inhaled 4.5% saline to produce a 20% fall in FEV1. Salbutamol 200 μg or ipratropium bromide 40 μg was then inhaled and the FEV1 was monitored for 30 minutes. Four study arms compared the response to each bronchodilator after formoterol and placebo. Analyses compared the area under the bronchodilator response curves, adjusting for changes in pre-challenge FEV1, dose of provocational agent and FEV1 fall during the challenge procedure. Results The response to nebulised salbutamol was 15% lower after formoterol therapy compared to placebo (95% confidence 5 to 25%, p = 0.008. The response to ipratropium was unchanged. Conclusion Long-acting beta-agonist treatment induces tolerance to the bronchodilator effect of beta-agonists, which is not overcome by higher dose nebulised salbutamol. However, the bronchodilator response to ipratropium bromide is unaffected.

  12. Switch from antagonist to agonist after addition of a DOTA chelator to a somatostatin analog

    International Nuclear Information System (INIS)

    Reubi, Jean Claude; Cescato, Renzo; Waser, Beatrice; Erchegyi, Judit; Rivier, Jean E.

    2010-01-01

    Peptide receptor targeting has become an increasingly attractive method to target tumors diagnostically and radiotherapeutically. Peptides linked to a variety of chelators have been developed for this purpose. They have, however, rarely been tested for their agonistic or antagonistic properties. We report here on a somatostatin antagonist that switched to an agonist upon coupling to a DOTA chelator. Two novel somatostatin analogs, 406-040-15 and its DOTA-coupled counterpart 406-051-20, with and without cold Indium labeling, were tested for their somatostatin receptor subtypes 1-5 (sst 1 -sst 5 ) binding affinity using receptor autoradiography. Moreover, they were tested functionally for their ability to affect sst 2 and sst 3 internalization in vitro in HEK293 cells stably expressing the human sst 2 or sst 3 receptor, using an immunofluorescence microscopy-based internalization assay. All three compounds were characterized as pan-somatostatin analogs having a high affinity for all five sst. In the sst 2 internalization assay, all three compounds showed an identical behavior, namely, a weak agonistic effect complemented by a weak antagonistic effect, compatible with the behavior of a partial agonist. Conversely, in the sst 3 internalization assay, 406-040-15 was a full antagonist whereas its DOTA-coupled counterpart, 406-051-20, with and without Indium labeling, switched to a full agonist. Adding the DOTA chelator to the somatostatin analog 406-040-15 triggers a switch at sst 3 receptor from an antagonist to an agonist. This indicates that potential radioligands for tumor targeting should always be tested functionally before further development, in particular if a chelator is added. (orig.)

  13. Species-specific action of (Pro3)GIP - an efficacious agonist on human GIP receptor, but partial agonist and competitive antagonist on rat and mouse GIP receptors

    DEFF Research Database (Denmark)

    Sparre-Ulrich, A H; Hansen, Lærke Smidt; Svendsen, B

    2016-01-01

    effect in murine studies. We conducted a pharmacological analysis of this ligand including interspecies differences between the rodent and human GIP system. EXPERIMENTAL APPROACH: Transiently transfected COS-7 cells were assessed for cAMP accumulation upon ligand stimulation and assayed in competition...... level. Thus, in rodent models human GIP is a comparatively weak partial agonist. Human (Pro3)GIP is not an effective antagonist, so there is still a need for an effective antagonist for the elucidation of GIP's physiology....

  14. Identification of potent, nonabsorbable agonists of the calcium-sensing receptor for GI-specific administration.

    Science.gov (United States)

    Sparks, Steven M; Spearing, Paul K; Diaz, Caroline J; Cowan, David J; Jayawickreme, Channa; Chen, Grace; Rimele, Thomas J; Generaux, Claudia; Harston, Lindsey T; Roller, Shane G

    2017-10-15

    Modulation of gastrointestinal nutrient sensing pathways provides a promising a new approach for the treatment of metabolic diseases including diabetes and obesity. The calcium-sensing receptor has been identified as a key receptor involved in mineral and amino acid nutrient sensing and thus is an attractive target for modulation in the intestine. Herein we describe the optimization of gastrointestinally restricted calcium-sensing receptor agonists starting from a 3-aminopyrrolidine-containing template leading to the identification of GI-restricted agonist 19 (GSK3004774). Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Lixisenatide, a novel GLP-1 receptor agonist for the treatment of type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Christensen, Mikkel; Knop, Filip K; Holst, Jens J

    2009-01-01

    Lixisenatide, under development by sanofi-aventis, is a novel human glucagon-like peptide-1 receptor (GLP-1R) agonist for the treatment of type 2 diabetes mellitus (T2DM; non-insulin dependent diabetes). The structure of lixisenatide, based on exendin-4(1-39) modified C-terminally with six Lys...... of the anticipated effects of lixisenatide on glycemic measures and weight; favorable results would place lixisenatide for consideration among other GLP-1R agonists in the treatment armamentarium for T2DM....

  16. Dopamine agonist increases risk taking but blunts reward-related brain activity.

    Directory of Open Access Journals (Sweden)

    Jordi Riba

    Full Text Available The use of D2/D3 dopaminergic agonists in Parkinson's disease (PD may lead to pathological gambling. In a placebo-controlled double-blind study in healthy volunteers, we observed riskier choices in a lottery task after administration of the D3 receptor-preferring agonist pramipexole thus mimicking risk-taking behavior in PD. Moreover, we demonstrate decreased activation in the rostral basal ganglia and midbrain, key structures of the reward system, following unexpected high gains and therefore propose that pathological gambling in PD results from the need to seek higher rewards to overcome the blunted response in this system.

  17. Biostructural and pharmacological studies of bicyclic analogues of the 3-isoxazolol glutamate receptor agonist ibotenic acid

    DEFF Research Database (Denmark)

    Frydenvang, Karla Andrea; Pickering, Darryl S; Greenwood, Jeremy R

    2010-01-01

    We describe an improved synthesis and detailed pharmacological characterization of the conformationally restricted analogue of the naturally occurring nonselective glutamate receptor agonist ibotenic acid (RS)-3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-7-carboxylic acid (7-HPCA, 5......) at AMPA receptor subtypes. Compound 5 was shown to be a subtype-discriminating agonist at AMPA receptors with higher binding affinity and functional potency at GluA1/2 compared to GluA3/4, unlike the isomeric analogue (RS)-3-hydroxy-4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridine-5-carboxylic acid (5-HPCA, 4...

  18. Ghrelin receptor agonist (TZP-101) accelerates gastric emptying in adults with diabetes and symptomatic gastroparesis

    DEFF Research Database (Denmark)

    Ejskjaer, N; Vestergaard, E T; Hellström, P M

    2009-01-01

    BACKGROUND: TZP-101 is a synthetic, selective ghrelin agonist in development for gastroparesis. AIM: To assess safety and effects of TZP-101 in diabetes patients with symptomatic gastroparesis. METHODS: Adults with type 1 or type 2 diabetes mellitus received placebo and TZP-101 (80, 160, 320 or 600...... between TZP-101 and placebo. CONCLUSIONS: This proof-of-concept study demonstrates that the ghrelin agonist TZP-101 is well-tolerated in diabetes patients with moderate-to-severe chronic gastroparesis and shows statistically significant improvements in gastric emptying....

  19. Quantitative protein and fat metabolism in bull calves treated with beta-adrenergic agonist

    DEFF Research Database (Denmark)

    Chwalibog, André; Jensen, K; Thorbek, G

    1996-01-01

    Protein and energy utilization and quantitative retention of protein, fat and energy was investigated with 12 Red Danish bulls during two subsequent 6 weeks trials (Sections A and B) at a mean live weight of 195 and 335 kg respectively. Treatments were control (Group 1) and beta-agonist (L-644...... matter, metabolizable energy and digestible protein was of the same magnitude for all groups. The beta-agonist had no significant effect on protein digestibility and metabolizability of energy, but daily live weight gain was significantly higher in the treated bulls. The utilization of digested protein...

  20. The luteal phase after GnRH-agonist triggering of ovulation: present and future perspectives

    DEFF Research Database (Denmark)

    Humaidan, Peter; Papanikolaou, E G; Kyrou, D

    2012-01-01

    In stimulated IVF/intracytoplasmic sperm injection cycles, the luteal phase is disrupted, necessitating luteal-phase supplementation. The most plausible reason behind this is the ovarian multifollicular development obtained after ovarian stimulation, resulting in supraphysiological steroid...... with a GnRH agonist instead of human chorionic gonadotrophin (HCG). The first studies applying this concept, however, showed a very poor pregnancy rate, despite standard luteal-phase support with progesterone. This review discusses the reason for the poor results and the newest studies, using GnRH agonist...

  1. Reports of pathological gambling, hypersexuality, and compulsive shopping associated with dopamine receptor agonist drugs.

    Science.gov (United States)

    Moore, Thomas J; Glenmullen, Joseph; Mattison, Donald R

    2014-12-01

    Severe impulse control disorders involving pathological gambling, hypersexuality, and compulsive shopping have been reported in association with the use of dopamine receptor agonist drugs in case series and retrospective patient surveys. These agents are used to treat Parkinson disease, restless leg syndrome, and hyperprolactinemia. To analyze serious adverse drug event reports about these impulse control disorders received by the US Food and Drug Administration (FDA) and to assess the relationship of these case reports with the 6 FDA-approved dopamine receptor agonist drugs. We conducted a retrospective disproportionality analysis based on the 2.7 million serious domestic and foreign adverse drug event reports from 2003 to 2012 extracted from the FDA Adverse Event Reporting System. Cases were selected if they contained any of 10 preferred terms in the Medical Dictionary for Regulatory Activities (MedDRA) that described the abnormal behaviors. We used the proportional reporting ratio (PRR) to compare the proportion of target events to all serious events for the study drugs with a similar proportion for all other drugs. We identified 1580 events indicating impulse control disorders from the United States and 21 other countries:710 fordopamine receptor agonist drugs and 870 for other drugs. The dopamine receptor agonist drugs had a strong signal associated with these impulse control disorders (n = 710; PRR = 277.6, P < .001). The association was strongest for the dopamine agonists pramipexole (n = 410; PRR = 455.9, P < .001) and ropinirole (n = 188; PRR = 152.5, P < .001), with preferential affinity for the dopamine D3 receptor. A signal was also seen for aripiprazole, an antipsychotic classified as a partial agonist of the D3 receptor (n = 37; PRR = 8.6, P < .001). Our findings confirm and extend the evidence that dopamine receptor agonist drugs are associated with these specific impulse control disorders. At present

  2. Antagonist-agonist combinations as therapies for heroin addiction: back to the future?

    Science.gov (United States)

    Nutt, David J

    2010-02-01

    Psychopharmacology is a powerful approach to the treatment of many psychiatric disorders. In this article I discuss the conceptual and practical issues in relation to the use of mu opioid receptor agonist, antagonist and partial agonist drugs in the treatment of opioid addiction, as this is one therapeutic area where all three types of agents are currently available. The choice of pharmacological agent is largely determined by patient profile, existence of ongoing drug misuse, and the kinetics of the drugs available. These principles, however, can be applied to other disorders as and when other pharmacological approaches become refined in these areas.

  3. Correlating the Metabolic Stability of Psychedelic 5-HT2A Agonists with Anecdotal Reports of Human Oral Bioavailability

    DEFF Research Database (Denmark)

    Leth-Petersen, Sebastian; Bundgaard, Christoffer; Hansen, Martin

    2014-01-01

    2,5-Dimethoxyphenethylamines and their N-benzylated derivatives are potent 5-HT2A agonists with psychedelic effects in humans. The N-benzylated derivatives are among the most selective 5-HT2A agonists currently available and their usage as biochemical and brain imaging tools is increasing, yet ve...

  4. Combined inhalation of beta2 -agonists improves swim ergometer sprint performance but not high-intensity swim performance

    DEFF Research Database (Denmark)

    Kalsen, Anders; Hostrup, Morten; Bangsbo, Jens

    2014-01-01

    There is a high prevalence of asthma and airway hyperresponsiveness (AHR) in elite athletes, which leads to a major use of beta2 -agonists. In a randomized double-blinded crossover study, we investigated the effects of combined inhalation of beta2 -agonists (salbutamol, formoterol, and salmeterol...

  5. Pharmacological Characterization of 30 Human Melanocortin-4 Receptor Polymorphisms with the Endogenous Proopiomelanocortin Derived Agonists, Synthetic Agonists, and the Endogenous Agouti-Related Protein (AGRP) Antagonist

    Science.gov (United States)

    Xiang, Zhimin; Proneth, Bettina; Dirain, Marvin L.; Litherland, Sally A.; Haskell-Luevano, Carrie

    2010-01-01

    The melanocortin-4 receptor (MC4R) is a G-protein coupled receptor (GPCR) that is expressed in the central nervous system and has a role in regulating feeding behavior, obesity, energy homeostasis, male erectile response, and blood pressure. Since the report of the MC4R knockout mouse in 1997, the field has been searching for links between this genetic bio marker and human obesity and type 2 diabetes. More then 80 single nucleotide polymorphisms (SNPs) have been identified from human patients, both obese and non-obese controls. Many significant studies have been performed examining the pharmacological characteristics of these hMC4R SNPs in attempts to identify a molecular defects/insights that might link a genetic factor to the obese phenotype observed in patients possessing these mutations. Our laboratory has previously reported the pharmacological characterization of 40 of these polymorphic hMC4 receptors with multiple endogenous and synthetic ligands. The goal of the current study is to perform a similar comprehensive side-by-side characterization of 30 additional human hMC4R with single nucleotide polymorphisms using multiple endogenous agonists [α-, β, γ2-melanocyte stimulating hormones (MSH) and adrenocorticotropin (ACTH)], the antagonist agouti-related protein hAGRP(87-132), and synthetic agonists [NDP-MSH, MTII, and the tetrapeptide Ac-His-DPhe-Arg-Trp-NH2 (JRH887-9)]. These in vitro data, in some cases, provide a putative molecular link between dysfunctional hMC4R's and human obesity. These 30 hMC4R SNPs include R7H, R18H, R18L, S36Y, P48S, V50M, F51L, E61K, I69T, D90N, S94R, G98R, I121T, A154D, Y157S, W174C, G181D, F202L, A219V, I226T, G231S, G238D, N240S, C271R, S295P, P299L, E308K, I317V, L325F and 750DelGA. All but the N240S hMC4R were identified in obese patients. Additionally, we have characterized a double I102T/V103I hMC4R. In addition to the pharmacological characterization, the hMC4R variants were evaluated for cell surface expression by flow

  6. Pharmacological characterization of 30 human melanocortin-4 receptor polymorphisms with the endogenous proopiomelanocortin-derived agonists, synthetic agonists, and the endogenous agouti-related protein antagonist.

    Science.gov (United States)

    Xiang, Zhimin; Proneth, Bettina; Dirain, Marvin L; Litherland, Sally A; Haskell-Luevano, Carrie

    2010-06-08

    The melanocortin-4 receptor (MC4R) is a G-protein-coupled receptor (GPCR) that is expressed in the central nervous system and has a role in regulating feeding behavior, obesity, energy homeostasis, male erectile response, and blood pressure. Since the report of the MC4R knockout mouse in 1997, the field has been searching for links between this genetic biomarker and human obesity and type 2 diabetes. More then 80 single nucleotide polymorphisms (SNPs) have been identified from human patients, both obese and nonobese controls. Many significant studies have been performed examining the pharmacological characteristics of these hMC4R SNPs in attempts to identify a molecular defects/insights that might link a genetic factor to the obese phenotype observed in patients possessing these mutations. Our laboratory has previously reported the pharmacological characterization of 40 of these polymorphic hMC4 receptors with multiple endogenous and synthetic ligands. The goal of the current study is to perform a similar comprehensive side-by-side characterization of 30 additional human hMC4R with single nucleotide polymorphisms using multiple endogenous agonists [alpha-, beta-, and gamma(2)-melanocyte stimulating hormones (MSH) and adrenocorticotropin (ACTH)], the antagonist agouti-related protein hAGRP(87-132), and synthetic agonists [NDP-MSH, MTII, and the tetrapeptide Ac-His-dPhe-Arg-Trp-NH(2) (JRH887-9)]. These in vitro data, in some cases, provide a putative molecular link between dysfunctional hMC4R's and human obesity. These 30 hMC4R SNPs include R7H, R18H, R18L, S36Y, P48S, V50M, F51L, E61K, I69T, D90N, S94R, G98R, I121T, A154D, Y157S, W174C, G181D, F202L, A219 V, I226T, G231S, G238D, N240S, C271R, S295P, P299L, E308K, I317V, L325F, and 750DelGA. All but the N240S hMC4R were identified in obese patients. Additionally, we have characterized a double I102T/V103I hMC4R. In addition to the pharmacological characterization, the hMC4R variants were evaluated for cell surface

  7. Preclinical evaluation of SMM-189, a cannabinoid receptor 2-specific inverse agonist.

    Science.gov (United States)

    Presley, Chaela; Abidi, Ammaar; Suryawanshi, Satyendra; Mustafa, Suni; Meibohm, Bernd; Moore, Bob M

    2015-08-01

    Cannabinoid receptor 2 agonists and inverse agonists are emerging as new therapeutic options for a spectrum of autoimmune-related disease. Of particular interest, is the ability of CB2 ligands to regulate microglia function in neurodegenerative diseases and traumatic brain injury. We have previously reported the receptor affinity of 3',5'-dichloro-2,6-dihydroxy-biphenyl-4-yl)-phenyl-methanone (SMM-189) and the characterization of the beneficial effects of SMM-189 in the mouse model of mild traumatic brain injury. Herein, we report the further characterization of SMM-189 as a potent and selective CB2 inverse agonist, which acts as a noncompetitive inhibitor of CP 55,940. The ability of SMM-189 to regulate microglial activation, in terms of chemokine expression and cell morphology, has been determined. Finally, we have determined that SMM-189 possesses acceptable biopharmaceutical properties indicating that the triaryl class of CB2 inverse agonists are viable compounds for continued preclinical development for the treatment of neurodegenerative disorders and traumatic brain injury.

  8. Design and Discovery of Functionally Selective Serotonin 2C (5-HT2C) Receptor Agonists.

    Science.gov (United States)

    Cheng, Jianjun; McCorvy, John D; Giguere, Patrick M; Zhu, Hu; Kenakin, Terry; Roth, Bryan L; Kozikowski, Alan P

    2016-11-10

    On the basis of the structural similarity of our previous 5-HT 2C agonists with the melatonin receptor agonist tasimelteon and the putative biological cross-talk between serotonergic and melatonergic systems, a series of new (2,3-dihydro)benzofuran-based compounds were designed and synthesized. The compounds were evaluated for their selectivity toward 5-HT 2A , 5-HT 2B , and 5-HT 2C receptors in the calcium flux assay with the ultimate goal to generate selective 5-HT 2C agonists. Selected compounds were studied for their functional selectivity by comparing their transduction efficiency at the G protein signaling pathway versus β-arrestin recruitment. The most functionally selective compound (+)-7e produced weak β-arrestin recruitment and also demonstrated less receptor desensitization compared to serotonin in both calcium flux and phosphoinositide (PI) hydrolysis assays. We report for the first time that selective 5-HT 2C agonists possessing weak β-arrestin recruitment can produce distinct receptor desensitization properties.

  9. Unraveling the high- and low-sensitivity agonist responses of nicotinic acetylcholine receptors

    DEFF Research Database (Denmark)

    Harpsøe, Kasper; Ahring, Philip K; Christensen, Jeppe K

    2011-01-01

    The neuronal a4ß2 nicotinic acetylcholine receptors exist as two distinct subtypes, (a4)(2)(ß2)(3) and (a4)(3)(ß2)(2), and biphasic responses to acetylcholine and other agonists have been ascribed previously to coexistence of these two receptor subtypes. We offer a novel and radical explanation...

  10. Intersubunit bridge formation governs agonist efficacy at nicotinic acetylcholine alpha4beta2 receptors

    DEFF Research Database (Denmark)

    Rohde, Line Aagot Hede; Ahring, Philip Kiær; Jensen, Marianne Lerbech

    2012-01-01

    The a4ß2 subtype of the nicotinic acetylcholine receptor (nAChR) has been pursued as a drug target for treatment of psychiatric and neurodegenerative disorders and smoking cessation aids for decades. Still, a thorough understanding of structure-function relationships of a4ß2 agonists is lacking...

  11. Alpha-2 adrenergic agonists for the prevention of cardiac complications among adults undergoing surgery.

    Science.gov (United States)

    Duncan, Dallas; Sankar, Ashwin; Beattie, W Scott; Wijeysundera, Duminda N

    2018-03-06

    The surgical stress response plays an important role on the pathogenesis of perioperative cardiac complications. Alpha-2 adrenergic agonists attenuate this response and may help prevent postoperative cardiac complications. To determine the efficacy and safety of α-2 adrenergic agonists for reducing mortality and cardiac complications in adults undergoing cardiac surgery and non-cardiac surgery. We searched CENTRAL (2017, Issue 4), MEDLINE (1950 to April Week 4, 2017), Embase (1980 to May 2017), the Science Citation Index, clinical trial registries, and reference lists of included articles. We included randomized controlled trials that compared α-2 adrenergic agonists (i.e. clonidine, dexmedetomidine or mivazerol) against placebo or non-α-2 adrenergic agonists. Included trials had to evaluate the efficacy and safety of α-2 adrenergic agonists for preventing perioperative mortality or cardiac complications (or both), or measure one or more relevant outcomes (i.e. death, myocardial infarction, heart failure, acute stroke, supraventricular tachyarrhythmia and myocardial ischaemia). Two authors independently assessed trial quality, extracted data and independently performed computer entry of abstracted data. We contacted study authors for additional information. Adverse event data were gathered from the trials. We evaluated included studies using the Cochrane 'Risk of bias' tool, and the quality of the evidence underlying pooled treatment effects using GRADE methodology. Given the clinical heterogeneity between cardiac and non-cardiac surgery, we analysed these subgroups separately. We expressed treatment effects as pooled risk ratios (RR) with 95% confidence intervals (CI). We included 47 trials with 17,039 participants. Of these studies, 24 trials only included participants undergoing cardiac surgery, 23 only included participants undergoing non-cardiac surgery and eight only included participants undergoing vascular surgery. The α-2 adrenergic agonist studied

  12. Detection and identification of "new" beta-agonists in black-market preparations

    NARCIS (Netherlands)

    van Ginkel LA; Stephany RW; van Rossum HJ; Visser T; den Engelsman T; de Jong APJM; Jacquemijns M; Zomer G

    1992-01-01

    In several "black-market" used for growth promotion preparations new compounds were found belonging to the group of N-phenylethanolamines with structures very similar to compounds known to be used for veal calf and cattle production, the so called beta-agonists. The two most important

  13. Treatment of Obesity-Related Complications with Novel Classes of Naturally Occurring PPAR Agonists.

    Science.gov (United States)

    Bassaganya-Riera, Josep; Guri, Amir J; Hontecillas, Raquel

    2011-01-01

    The prevalence of obesity and its associated comorbidities has grown to epidemic proportions in the US and worldwide. Thus, developing safe and effective therapeutic approaches against these widespread and debilitating diseases is important and timely. Activation of peroxisome proliferator-activated receptors (PPARs) α, γ, and δ through several classes of pharmaceuticals can prevent or treat a variety of metabolic and inflammatory diseases, including type II diabetes (T2D). Thus, PPARs represent important molecular targets for developing novel and better treatments for a wide range of debilitating and widespread obesity-related diseases and disorders. However, available PPAR γ agonistic drugs such as Avandia have significant adverse side effects, including weight gain, fluid retention, hepatotoxicity, and congestive heart failure. An alternative to synthetic agonists of PPAR γ is the discovery and development of naturally occurring and safer nutraceuticals that may be dual or pan PPAR agonists. The purpose of this paper is to summarize the health effects of three plant-derived PPAR agonists: abscisic acid (ABA), punicic acid (PUA), and catalpic acid (CAA) in the prevention and treatment of chronic inflammatory and metabolic diseases and disorders.

  14. THE MORPHOLOGICAL BASIS FOR OLFACTORY PERCEPTION OF STEROIDS DUING AGONISTIC BEHAVIOR IN LOBSTER: PRELIMINARY EXPERIMENTS

    Science.gov (United States)

    The morphological basis for olfactory perception of steroids during agonistic behavior in lobsters: preliminary experiments. Borsay Horowitz, DJ1, Kass-Simon, G2, Coglianese, D2, Martin, L2, Boseman, M2, Cromarty, S3, Randall, K3, Fini, A.3 1US EPA, NHEERL, ORD, Atlantic Ecology...

  15. Agonistic Recognition in Education: On Arendt's Qualification of Political and Moral Meaning

    Science.gov (United States)

    Ljunggren, Carsten

    2010-01-01

    Agonistic recognition in education has three interlinked modes of aesthetic experience and self-presentation where one is related to actions in the public realm; one is related to plurality in the way in which it comes into existence in confrontation with others; and one is related to the subject-self, disclosed by "thinking. Arendt"s conception…

  16. The GABAA receptor agonist THIP is neuroprotective in organotypic hippocampal slice cultures

    DEFF Research Database (Denmark)

    Kristensen, Bjarne Winther; Noraberg, Jens; Zimmer, Jens

    2003-01-01

    The potential neuroprotective effects of the GABA(A) receptor agonists THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and muscimol, and the selective GluR5 kainate receptor agonist ATPA ((RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl)propanoic acid), which activates GABAergic interneu......The potential neuroprotective effects of the GABA(A) receptor agonists THIP (4,5,6,7-tetrahydroisoxazolo[5,4-c]pyridin-3-ol) and muscimol, and the selective GluR5 kainate receptor agonist ATPA ((RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl)propanoic acid), which activates GABAergic...... interneurons, were examined in hippocampal slice cultures exposed to N-methyl-D-aspartate (NMDA). The NMDA-induced excitotoxicity was quantified by densitometric measurements of propidium iodide (PI) uptake. THIP (100-1000 microM) was neuroprotective in slice cultures co-exposed to NMDA (10 microM) for 48 h......, while muscimol (100-1000 microM) and ATPA (1-3 microM) were without effect. The results demonstrate that direct GABA(A) agonism can mediate neuroprotection in the hippocampus in vitro as previously suggested in vivo....

  17. Therapeutic efficacy of the adenosine A1 receptor agonist N6-cyclopentyladenosine (CPA) against organophosphate intoxication

    NARCIS (Netherlands)

    Bueters, T.J.H.; Groen, B.; Danhof, M.; IJzerman, A.P.; Helden, H.P.M. van

    2002-01-01

    The objective of the present study was to investigate whether reduction of central acetylcholine (ACh) accumulation by adenosine receptor agonists could serve as a generic treatment against organophosphate (OP) poisoning. The OPs studied were tabun (O-ethyl-N-dimethylphosphoramidocyanidate), sarin

  18. Final height after gonadotrophin releasing hormone agonist treatment for central precocious puberty : The Dutch experience

    NARCIS (Netherlands)

    Mul, D; Oostdijk, W; Otten, BJ; Rouwe, C; Jansen, M; Delemarre-van de Waal, HA; Waelkens, JJJ; Drop, SLS

    Final height (FH) data of 96 children (87 girls) treated with GnRH agonist for central precocious puberty were studied. In girls mean FH exceeded initial height prediction by 7.4 (5.7) cm (p <0.001); FH was significantly lower than target height, but still in the genetic target range. When treatment

  19. Small Molecule Agonists of Cell Adhesion Molecule L1 Mimic L1 Functions In Vivo.

    Science.gov (United States)

    Kataria, Hardeep; Lutz, David; Chaudhary, Harshita; Schachner, Melitta; Loers, Gabriele

    2016-09-01

    Lack of permissive mechanisms and abundance of inhibitory molecules in the lesioned central nervous system of adult mammals contribute to the failure of functional recovery after injury, leading to severe disabilities in motor functions and pain. Peripheral nerve injury impairs motor, sensory, and autonomic functions, particularly in cases where nerve gaps are large and chronic nerve injury ensues. Previous studies have indicated that the neural cell adhesion molecule L1 constitutes a viable target to promote regeneration after acute injury. We screened libraries of known drugs for small molecule agonists of L1 and evaluated the effect of hit compounds in cell-based assays in vitro and in mice after femoral nerve and spinal cord injuries in vivo. We identified eight small molecule L1 agonists and showed in cell-based assays that they stimulate neuronal survival, neuronal migration, and neurite outgrowth and enhance Schwann cell proliferation and migration and myelination of neurons in an L1-dependent manner. In a femoral nerve injury mouse model, enhanced functional regeneration and remyelination after application of the L1 agonists were observed. In a spinal cord injury mouse model, L1 agonists improved recovery of motor functions, being paralleled by enhanced remyelination, neuronal survival, and monoaminergic innervation, reduced astrogliosis, and activation of microglia. Together, these findings suggest that application of small organic compounds that bind to L1 and stimulate the beneficial homophilic L1 functions may prove to be a valuable addition to treatments of nervous system injuries.

  20. Effect of long-acting beta2 agonists on exacerbation rates of asthma in children

    DEFF Research Database (Denmark)

    Bisgaard, Hans

    2003-01-01

    The purpose of this analysis was to examine the effect of long-acting beta(2)-adrenoceptor agonists (LABAs) on the asthma exacerbation rate in pediatric patients. Randomized controlled trials (RCT) that included the use of LABAs to treat symptoms of pediatric asthma in children on inhaled cortico...

  1. Bioassay directed identification of natural aryl hydrocarbon-receptor agonists in marmalade

    NARCIS (Netherlands)

    Ede, van K.I.; Li, A.; Antunes Fernandes, E.C.; Mulder, P.P.J.; Peijnenburg, A.A.C.M.; Hoogenboom, L.A.P.

    2008-01-01

    Citrus fruit and citrus fruit products, like grapefruit, lemon and marmalade were shown to contain aryl hydrocarbon receptor (AhR) agonists, as detected with the DR CALUX® bioassay. This is of interest regarding the role of the Ah-receptor pathway in the adverse effects of dioxins, PCBs and other

  2. Novel non-indolic melatonin receptor agonists differentially entrain endogenous melatonin rhythm and increase its amplitude

    NARCIS (Netherlands)

    Drijfhout, W.J; de Vries, J.B; Homan, E.J; Brons, H.F; Copinga, S; Gruppen, G; Beresford, I.J M; Hagan, R.M; Grol, Cor; Westerink, B.H.C.

    1999-01-01

    In this study we have examined the ability of melatonin and four synthetic melatonin receptor agonists to entrain endogenous melatonin secretion in rats, free running in constant darkness. The circadian melatonin profile was measured by trans-pineal microdialysis, which not only reveals the time of

  3. NICOTINE EFFECTS ON THE ACTIVITY OF MICE EXPOSED PRENATALLY TO THE NICOTINIC AGONIST ANATOXIN-A.

    Science.gov (United States)

    Considerable research has shown long-lasting effects of early exposure in experimental animals to nicotine. Anatoxin-a is produced by cyanobacteria and has been shown to be a potent nicotinic agonist. This experiment evaluated the motor activity of adult mice, and their respons...

  4. Differential Effects of Cannabinoid Receptor Agonist on Social Discrimination and Contextual Fear in Amygdala and Hippocampus

    Science.gov (United States)

    Segev, Amir; Akirav, Irit

    2011-01-01

    We examined whether the cannabinoid receptor agonist WIN55,212-2 (WIN; 5 [mu]g/side) microinjected into the hippocampus or the amygdala would differentially affect memory processes in a neutral vs. an aversive task. In the aversive contextual fear task, WIN into the basolateral amygdala impaired fear acquisition/consolidation, but not retrieval.…

  5. Drug-induced Hypothermia by 5HT1A Agonists Provide Neuroprotection in Experimental Stroke

    DEFF Research Database (Denmark)

    Johansen, Flemming Fryd; Hasseldam, Henrik; Nybro Smith, Matthias

    2014-01-01

    BACKGROUND: Drug-induced hypothermia reduces brain damage in animal stroke models and is an undiscovered potential in human stroke treatment. We studied hypothermia induced by the serotonergic agonists S14671 (1-[2-(2-thenoylamino)ethyl]-4[1-(7- methoxynaphtyl)]piperazine) and ipsapirone in a rat...... therapeutic hypothermia....

  6. The angiotensin type 2 receptor agonist Compound 21 elicits cerebroprotection in endothelin-1 induced ischemic stroke

    DEFF Research Database (Denmark)

    Joseph, Jason P; Mecca, Adam P; Regenhardt, Robert W

    2014-01-01

    Evidence indicates that angiotensin II type 2 receptors (AT2R) exert cerebroprotective actions during stroke. A selective non-peptide AT2R agonist, Compound 21 (C21), has been shown to exert beneficial effects in models of cardiac and renal disease, as well as hemorrhagic stroke. Here, we hypothe...

  7. GnRH-agonist versus GnRH-antagonist IVF cycles

    DEFF Research Database (Denmark)

    Papanikolaou, E G; Pados, G; Grimbizis, G

    2012-01-01

    In view of the current debate concerning possible differences in efficacy between the two GnRH analogues used in IVF stimulated cycles, the current study aimed to explore whether progesterone control in the late follicular phase differs when GnRH antagonist is used as compared with GnRH agonist...

  8. Tweaking agonist efficacy at N-methyl-D-aspartate receptors by site-directed mutagenesis

    DEFF Research Database (Denmark)

    Hansen, Kasper B; Clausen, Rasmus P; Bjerrum, Esben J

    2005-01-01

    The structural basis for partial agonism at N-methyl-D-aspartate (NMDA) receptors is currently unresolved. We have characterized several partial agonists at the NR1/NR2B receptor and investigated the mechanisms underlying their reduced efficacy by introducing mutations in the glutamate binding site...

  9. Homologous histamine H1 receptor desensitization results in reduction of H1 receptor agonist efficacy

    NARCIS (Netherlands)

    Leurs, R; Smit, M J; Bast, A; Timmerman, H

    1991-01-01

    Prolonged exposure of the guinea-pig intestinal longitudinal smooth muscle to histamine caused homologous desensitization of the H1 receptor, which led to reduced H1 receptor-mediated production of [3H]inositol phosphates as well as to reduced H1 agonist-induced contractions. [3H]Mepyramine binding

  10. Relaxing action of adrenergic β2-agonists on guinea-pig skinned tracheal muscle

    Directory of Open Access Journals (Sweden)

    Kayo Nemoto

    1999-01-01

    Full Text Available Although adrenergic β2-agonist-induced smooth muscle relaxation has been attributed to increased intracellular cyclic AMP (cAMP, a relaxation response has been observed at low β2-agonist concentrations that do not cause increased cAMP To elucidate the mechanism of tracheal muscle relaxation induced by low concentrations of β2-agonists, we used a guinea-pig skinned tracheal smooth muscle preparation to examine the effects on the contractile protein system. The isotonic contraction of β-escin-treated skinned tracheal muscle from guinea-pig was measured. When the intracellular Ca2+ concentration was maintained at 1 μmol/L in the presence of guanosine 5′-triphosphate (GTP; 100 μmol/L, neither isoproterenol (10nmol/L nor salbutamol (60 nmol/L affected Ca2+ sensitivity, but a significant decrease in Ca2+ sensitivity was observed in the presence of okadaic acid (1 μmol/L. The decrease in Ca2+ sensitivity was a slow response and was blocked by pretreatment with propranolol (1 μmol/L. Forskolin (1 μmol/L did not affect Ca2+ sensitivity. These results suggest that adrenergic b 2-agonists may activate protein phosphatase through an unknown pathway involving the β2-receptor, which enhances dephosphorylation of the myosin light chain and/or thin filament proteins, resulting in relaxation of the tracheal smooth muscle.

  11. Oxidation of nutrients in bull calves treated with beta-adrenergic agonists

    DEFF Research Database (Denmark)

    Chwalibog, André; Jensen, K; Thorbek, G

    1996-01-01

    Oxidation of protein (OXP), carbohydrate (OXCHO) and fat (OXF) was investigated with 12 growing bulls treated with beta-agonist (L-644, 969) during two 6 weeks trials (Section A and B) at a mean live weight of 195 and 335 kg. Heat production and nutrient oxidation was calculated from gas exchange...

  12. The GPR120 agonist TUG-891 promotes metabolic health by stimulating mitochondrial respiration in brown fat

    DEFF Research Database (Denmark)

    Schilperoort, Maaike; van Dam, Andrea D; Hoeke, Geerte

    2018-01-01

    the therapeutic potential of GPR120 agonism and addressed GPR120-mediated signaling in BAT We found that activation of GPR120 by the selective agonist TUG-891 acutely increases fat oxidation and reduces body weight and fat mass in C57Bl/6J mice. These effects coincided with decreased brown adipocyte lipid content...

  13. Major drawbacks and additional benefits of agonist trigger--not ovarian hyperstimulation syndrome related

    DEFF Research Database (Denmark)

    Shapiro, Bruce S; Andersen, Claus Yding

    2015-01-01

    optimal luteal support. The agonist trigger option also allows continued stimulation and subsequent trigger of high responders with reasonable safety, potentially leading to retrievals of larger cohorts of mature oocytes. It may also reduce the number of retrievals needed to achieve a large family...

  14. Gonadotropin-releasing hormone agonist versus HCG for oocyte triggering in antagonist assisted reproductive technology cycles

    NARCIS (Netherlands)

    Youssef, Mohamed A. F. M.; van der Veen, Fulco; Al-Inany, Hesham G.; Griesinger, Georg; Mochtar, Monique H.; Aboulfoutouh, Ismail; Khattab, Sherif M.; van Wely, Madelon

    2011-01-01

    Background Gonadotropin-releasing hormone (GnRH) antagonist protocols for pituitary down regulation in in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) allow the use of GnRH agonists for triggering final oocyte maturation. Currently, human chorionic gonadotropin (HCG) is

  15. Platelet-activating factor receptor agonists mediate xeroderma pigmentosum A photosensitivity.

    Science.gov (United States)

    Yao, Yongxue; Harrison, Kathleen A; Al-Hassani, Mohammed; Murphy, Robert C; Rezania, Samin; Konger, Raymond L; Travers, Jeffrey B

    2012-03-16

    To date, oxidized glycerophosphocholines (Ox-GPCs) with platelet-activating factor (PAF) activity produced non-enzymatically have not been definitively demonstrated to mediate any known disease processes. Here we provide evidence that these Ox-GPCs play a pivotal role in the photosensitivity associated with the deficiency of the DNA repair protein xeroderma pigmentosum type A (XPA). It should be noted that XPA-deficient cells are known to have decreased antioxidant defenses. These studies demonstrate that treatment of human XPA-deficient fibroblasts with the pro-oxidative stressor ultraviolet B (UVB) radiation resulted in increased reactive oxygen species and PAF receptor (PAF-R) agonistic activity in comparison with gene-corrected cells. The UVB irradiation-generated PAF-R agonists were inhibited by antioxidants. UVB irradiation of XPA-deficient (Xpa-/-) mice also resulted in increased PAF-R agonistic activity and skin inflammation in comparison with control mice. The increased UVB irradiation-mediated skin inflammation and TNF-α production in Xpa-/- mice were blocked by systemic antioxidants and by PAF-R antagonists. Structural characterization of PAF-R-stimulating activity in UVB-irradiated XPA-deficient fibroblasts using mass spectrometry revealed increased levels of sn-2 short-chain Ox-GPCs along with native PAF. These studies support a critical role for PAF-R agonistic Ox-GPCs in the pathophysiology of XPA photosensitivity.

  16. Novel Zn2+ Modulated GPR39 Receptor Agonists Do Not Drive Acute Insulin Secretion in Rodents.

    Directory of Open Access Journals (Sweden)

    Ola Fjellström

    Full Text Available Type 2 diabetes (T2D occurs when there is insufficient insulin release to control blood glucose, due to insulin resistance and impaired β-cell function. The GPR39 receptor is expressed in metabolic tissues including pancreatic β-cells and has been proposed as a T2D target. Specifically, GPR39 agonists might improve β-cell function leading to more adequate and sustained insulin release and glucose control. The present study aimed to test the hypothesis that GPR39 agonism would improve glucose stimulated insulin secretion in vivo. A high throughput screen, followed by a medicinal chemistry program, identified three novel potent Zn2+ modulated GPR39 agonists. These agonists were evaluated in acute rodent glucose tolerance tests. The results showed a lack of glucose lowering and insulinotropic effects not only in lean mice, but also in diet-induced obese (DIO mice and Zucker fatty rats. It is concluded that Zn2+ modulated GPR39 agonists do not acutely stimulate insulin release in rodents.

  17. The convulsive and electroencephalographic changes produced by nonpeptidic delta-opioid agonists in rats: comparison with pentylenetetrazol.

    Science.gov (United States)

    Jutkiewicz, Emily M; Baladi, Michelle G; Folk, John E; Rice, Kenner C; Woods, James H

    2006-06-01

    delta-Opioid agonists produce convulsions and antidepressant-like effects in rats. It has been suggested that the antidepressant-like effects are produced through a convulsant mechanism of action either through overt convulsions or nonconvulsive seizures. This study evaluated the convulsive and seizurogenic effects of nonpeptidic delta-opioid agonists at doses that previously were reported to produce antidepressant-like effects. In addition, delta-opioid agonist-induced electroencephalographic (EEG) and behavioral changes were compared with those produced by the chemical convulsant pentylenetetrazol (PTZ). For these studies, EEG changes were recorded using a telemetry system before and after injections of the delta-opioid agonists [(+)-4-[(alphaR)-alpha-[(2S,5R)-2,5-dimethyl-4-(2-propenyl)-1-piperazinyl]-(3-methoxyphenyl)methyl]-N,N-diethylbenz (SNC80) and [(+)-4-[alpha(R)-alpha-[(2S,5R)-2,5-dimethyl-4-(2-propenyl)-1-piperazinyl]-(3-hydroxyphenyl)methyl]-N,N-diethylbenzamide [(+)-BW373U86]. Acute administration of nonpeptidic delta-opioid agonists produced bilateral ictal and paroxysmal spike and/or sharp wave discharges. delta-Opioid agonists produced brief changes in EEG recordings, and tolerance rapidly developed to these effects; however, PTZ produced longer-lasting EEG changes that were exacerbated after repeated administration. Studies with antiepileptic drugs demonstrated that compounds used to treat absence epilepsy blocked the convulsive effects of nonpeptidic delta-opioid agonists. Overall, these data suggest that delta-opioid agonist-induced EEG changes are not required for the antidepressant-like effects of these compounds and that neural circuitry involved in absence epilepsy may be related to delta-opioid agonist-induced convulsions. In terms of therapeutic development, these data suggest that it may be possible to develop delta-opioid agonists devoid of convulsive properties.

  18. Heterologous Expression in Remodeled C. elegans: A Platform for Monoaminergic Agonist Identification and Anthelmintic Screening.

    Science.gov (United States)

    Law, Wenjing; Wuescher, Leah M; Ortega, Amanda; Hapiak, Vera M; Komuniecki, Patricia R; Komuniecki, Richard

    2015-04-01

    Monoamines, such as 5-HT and tyramine (TA), paralyze both free-living and parasitic nematodes when applied exogenously and serotonergic agonists have been used to clear Haemonchus contortus infections in vivo. Since nematode cell lines are not available and animal screening options are limited, we have developed a screening platform to identify monoamine receptor agonists. Key receptors were expressed heterologously in chimeric, genetically-engineered Caenorhabditis elegans, at sites likely to yield robust phenotypes upon agonist stimulation. This approach potentially preserves the unique pharmacologies of the receptors, while including nematode-specific accessory proteins and the nematode cuticle. Importantly, the sensitivity of monoamine-dependent paralysis could be increased dramatically by hypotonic incubation or the use of bus mutants with increased cuticular permeabilities. We have demonstrated that the monoamine-dependent inhibition of key interneurons, cholinergic motor neurons or body wall muscle inhibited locomotion and caused paralysis. Specifically, 5-HT paralyzed C. elegans 5-HT receptor null animals expressing either nematode, insect or human orthologues of a key Gαo-coupled 5-HT1-like receptor in the cholinergic motor neurons. Importantly, 8-OH-DPAT and PAPP, 5-HT receptor agonists, differentially paralyzed the transgenic animals, with 8-OH-DPAT paralyzing mutant animals expressing the human receptor at concentrations well below those affecting its C. elegans or insect orthologues. Similarly, 5-HT and TA paralyzed C. elegans 5-HT or TA receptor null animals, respectively, expressing either C. elegans or H. contortus 5-HT or TA-gated Cl- channels in either C. elegans cholinergic motor neurons or body wall muscles. Together, these data suggest that this heterologous, ectopic expression screening approach will be useful for the identification of agonists for key monoamine receptors from parasites and could have broad application for the identification

  19. Agonistic Human Antibodies Binding to Lecithin-Cholesterol Acyltransferase Modulate High Density Lipoprotein Metabolism*

    Science.gov (United States)

    Gunawardane, Ruwanthi N.; Fordstrom, Preston; Piper, Derek E.; Masterman, Stephanie; Siu, Sophia; Liu, Dongming; Brown, Mike; Lu, Mei; Tang, Jie; Zhang, Richard; Cheng, Janet; Gates, Andrew; Meininger, David; Chan, Joyce; Carlson, Tim; Walker, Nigel; Schwarz, Margrit; Delaney, John; Zhou, Mingyue

    2016-01-01

    Drug discovery opportunities where loss-of-function alleles of a target gene link to a disease-relevant phenotype often require an agonism approach to up-regulate or re-establish the activity of the target gene. Antibody therapy is increasingly recognized as a favored drug modality due to multiple desirable pharmacological properties. However, agonistic antibodies that enhance the activities of the target enzymes are rarely developed because the discovery of agonistic antibodies remains elusive. Here we report an innovative scheme of discovery and characterization of human antibodies capable of binding to and agonizing a circulating enzyme lecithin cholesterol acyltransferase (LCAT). Utilizing a modified human LCAT protein with enhanced enzymatic activity as an immunogen, we generated fully human monoclonal antibodies using the XenoMouseTM platform. One of the resultant agonistic antibodies, 27C3, binds to and substantially enhances the activity of LCAT from humans and cynomolgus macaques. X-ray crystallographic analysis of the 2.45 Å LCAT-27C3 complex shows that 27C3 binding does not induce notable structural changes in LCAT. A single administration of 27C3 to cynomolgus monkeys led to a rapid increase of plasma LCAT enzymatic activity and a 35% increase of the high density lipoprotein cholesterol that was observed up to 32 days after 27C3 administration. Thus, this novel scheme of immunization in conjunction with high throughput screening may represent an effective strategy for discovering agonistic antibodies against other enzyme targets. 27C3 and other agonistic human anti-human LCAT monoclonal antibodies described herein hold potential for therapeutic development for the treatment of dyslipidemia and cardiovascular disease. PMID:26644477

  20. Allosteric activation of the follicle-stimulating hormone (FSH) receptor by selective, nonpeptide agonists.

    Science.gov (United States)

    Yanofsky, Stephen D; Shen, Emily S; Holden, Frank; Whitehorn, Erik; Aguilar, Barbara; Tate, Emily; Holmes, Christopher P; Scheuerman, Randall; MacLean, Derek; Wu, May M; Frail, Donald E; López, Francisco J; Winneker, Richard; Arey, Brian J; Barrett, Ronald W

    2006-05-12

    The pituitary glycoprotein hormones, luteinizing hormone and follicle-stimulating hormone (FSH), act through their cognate receptors to initiate a series of coordinated physiological events that results in germ cell maturation. Given the importance of FSH in regulating folliculogenesis and fertility, the development of FSH mimetics has been sought to treat infertility. Currently, purified and recombinant human FSH are the only FSH receptor (FSH-R) agonists available for infertility treatment. By screening unbiased combinatorial chemistry libraries, using a cAMP-responsive luciferase reporter assay, we discovered thiazolidinone agonists (EC50's = 20 microm) of the human FSH-R. Subsequent analog library screening and parallel synthesis optimization resulted in the identification of a potent agonist (EC50 = 2 nm) with full efficacy compared with FSH that was FSH-R-selective and -dependent. The compound mediated progesterone production in Y1 cells transfected with the human FSH-R (EC50 = 980 nm) and estradiol production from primary rat ovarian granulosa cells (EC50 = 10.5 nm). This and related compounds did not compete with FSH for binding to the FSH-R. Use of human FSH/thyroid-stimulating hormone (TSH) receptor chimeras suggested a novel mechanism for receptor activation through a binding site independent of the natural hormone binding site. This study is the first report of a high affinity small molecule agonist that activates a glycoprotein hormone receptor through an allosteric mechanism. The small molecule FSH receptor agonists described here could lead to an oral alternative to the current parenteral FSH treatments used clinically to induce ovarian stimulation for both in vivo and in vitro fertilization therapy.

  1. Antineoplastic Effects of PPARγ Agonists, with a Special Focus on Thyroid Cancer.

    Science.gov (United States)

    Ferrari, Silvia Martina; Materazzi, Gabriele; Baldini, Enke; Ulisse, Salvatore; Miccoli, Paolo; Antonelli, Alessandro; Fallahi, Poupak

    2016-01-01

    Peroxisome Proliferator-Activated Receptor-γ (PPARγ) is a ligand-activated nuclear hormone receptor that functions as transcription factor and plays an important role in lipid metabolism and insulin sensitization. Recent studies have shown that PPARγ is overexpressed in many tumor types, including cancers of breast, lung, pancreas, colon, glioblastoma, prostate and thyroid differentiated/anaplastic cancers. These data suggest a role of PPARγ in tumor development and/or progression. PPARγ is emerging as a growth-limiting and differentiation-promoting factor, and it exerts a tumor suppressor role. Moreover, naturally-occurring and synthetic PPARγ agonists promote growth inhibition and apoptosis. Thiazolidinediones (TZDs) are synthetic agonists of PPARγ that were developed to treat type II diabetes. These compounds also display anticancer effects which appear mainly to be independent of their PPARγ agonist activity. Various preclinical and clinical studies strongly suggest a role for TZDs both alone and in combination with existing chemotherapeutic agents, for the treatment of cancer. Differentiation therapy involves the use of agents with the ability to induce differentiation in cells that have lost this ability, i.e. cancer cells, targeting pathways capable of re-activating blocked terminal differentiation programs. PPARγ agonists have been shown to induce differentiation in solid tumors such as thyroid differentiated/ anaplastic cancers and sarcomas. However, emerging data suggest that chronic use of TZDs is associated with increased risk of adverse cardiovascular events. The exploration of newer PPARγ agonists can help in unveiling the underlying mechanisms of these drugs, providing new molecules that are able to treat cancer, without increasing the cardiovascular risk of neoplastic patients.

  2. Can the anti-inflammatory activities of β2-agonists be harnessed in the clinical setting?

    Directory of Open Access Journals (Sweden)

    Theron AJ

    2013-11-01

    Full Text Available Annette J Theron,1,2 Helen C Steel,1 Gregory R Tintinger,1 Charles Feldman,3 Ronald Anderson1 1Medical Research Council Unit for Inflammation and Immunity, Department of Immunology, Faculty of Health Sciences, University of Pretoria, 2Tshwane Academic Division of the National Health Laboratory Service, Pretoria, 3Division of Pulmonology, Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand and Charlotte Maxeke Johannesburg Academic Hospital, Johannesburg, South Africa Abstract: Beta2-adrenoreceptor agonists (β2-agonists are primarily bronchodilators, targeting airway smooth muscle and providing critical symptomatic relief in conditions such as bronchial asthma and chronic obstructive pulmonary disease. These agents also possess broad-spectrum, secondary, anti-inflammatory properties. These are mediated largely, though not exclusively, via interactions with adenylyl cyclase-coupled β2-adrenoreceptors on a range of immune and inflammatory cells involved in the immunopathogenesis of acute and chronic inflammatory disorders of the airways. The clinical relevance of the anti-inflammatory actions of β2-agonists, although often effective in the experimental setting, remains contentious. The primary objectives of the current review are: firstly, to assess the mechanisms, both molecular and cell-associated, that may limit the anti-inflammatory efficacy of β2-agonists; secondly, to evaluate pharmacological strategies, several of which are recent and innovative, that may overcome these limitations. These are preceded by a consideration of the various types of β2-agonists, their clinical applications, and spectrum of anti-inflammatory activities, particularly those involving adenosine 3',5'-cyclic adenosine monophosphate-activated protein kinase-mediated clearance of cytosolic calcium, and altered gene expression in immune and inflammatory cells. Keywords: adenylyl cyclase, corticosteroids, cyclic AMP, muscarinic

  3. Gonadotropin Releasing Hormone Agonists or Antagonists for Preimplantation Genetic Diagnosis (PGD)? A Prospective Randomised Trial.

    Science.gov (United States)

    Verpoest, Willem; De Vos, Anick; De Rycke, Martine; Parikh, Shruti; Staessen, Catherine; Tournaye, Herman; De Vos, Michel; Vloeberghs, Veerle; Blockeel, Christophe

    2017-11-10

    The use of GnRH analogue medication is essential in reproductive medicine to avoid premature ovulation by pituitary suppression for the duration of ovarian stimulation by gonadotrophins. The type of pituitary suppression by either GnRH agonist analogues versus GnRH antagonist analogues may result in different embryological hence clinical results. Preimplantation genetic diagnosis is a subtype of IVF in which embryos are created for genetic diagnosis of hereditary disorders in order to avoid genetically affected children. Embryological quality hence ovarian stimulation in preimplantation genetic diagnosis is crucial as genetic selection will reduce the number of available embryos to a fraction of the total. The aim of this study was to assess the efficiency of GnRH antagonist versus GnRH agonist treatment for pituitary suppression in ovarian stimulation for PGD, by proxy of number and quality of embryos at cleavage stage available for biopsy. We conducted a prospective randomised controlled trial comparing pituitary suppression by GnRH antagonist versus GnRH agonist in ovarian stimulation for PGD. The primary outcome measure was the number of embryos of sufficient quality for biopsy at cleavage stage. Secondary outcome parameters were the number of blastocysts available of top quality, and clinical pregnancy rate. There was no difference in number of oocytes retrieved, embryos at cleavage stage available for biopsy or embryo quality. The clinical pregnancy rate was higher in the GnRH agonist group; however the sample size was insufficient to allow conclusions. The use of GnRH agonist versus antagonist treatment does not result in differences in a number of oocytes, embryos or embryo quality in ovarian stimulation for preimplantation genetic diagnosis. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  4. Efficacy and Safety of GLP-1 Receptor Agonists for Type 2 Diabetes Mellitus Treatment: Systematic Review

    Directory of Open Access Journals (Sweden)

    Ana Paula Martins

    2016-04-01

    Full Text Available Introduction: Glucagon-like peptide analogues are a new class of drugs used in the treatment of type 2 diabetes mellitus that mimic the endogenous hormone glucagon-like peptide 1. Glucagon-like peptide 1 regulates glucose levels by stimulating glucose-dependent insulin secretion, suppressing glucagon secretion, delayed gastric emptying and promoting satiety. The individualized treatment of type 2 diabetes mellitus, using various glucagon--like peptide receptor agonists, has recently been described and the interest related to these drugs continues to grow. Objectives: To review the efficacy and safety of glucagon-like peptide 1 agonists in patients with inadequately controlled type 2 diabetes mellitus on metformin alone, highlighting their added value in therapeutic use comparatively to second line oral therapies used in type 2 diabetes mellitus. Methods: Studies were obtained from electronic searches of The Cochrane Library and PubMed. Randomized controlled trials were selected if they were at least 8 weeks in duration; compared a glucagon-like peptide 1 analogue with an oral anti-diabetic agent in patients experiencing inadequate glycemic control with metformin monotherapy; and reported hemoglobin A1c data in non-pregnant adults with type 2 diabetes mellitus. Results: Of 72 potentially relevant articles identified, 23 were retrieved for detailed evaluation and 10 met the inclusion criteria. The majority of glucagon-like peptide 1 agonists showed equivalent or superior efficacy than most active comparators for reducing hemoglobin A1c, with a greater proportion of patients achieving hemoglobin A1c <7%. Glucagon-like peptide 1 agonists also showed extra-glycemic effects such as weight loss and the reduction of important cardiovascular parameters. Side effects included gastrointestinal complications, mainly nausea, vomiting and diarrhea. The incidence of hypoglycemia was less common for this class of agents. Conclusion: Glucagon-like peptide 1

  5. Local administration of a hedgehog agonist accelerates fracture healing in a mouse model

    International Nuclear Information System (INIS)

    Kashiwagi, Miki; Hojo, Hironori; Kitaura, Yoshiaki; Maeda, Yujiro; Aini, Hailati; Takato, Tsuyoshi; Chung, Ung-il; Ohba, Shinsuke

    2016-01-01

    Bone fracture healing is processed through multiple biological stages including the transition from cartilaginous callus to bony callus formation. Because of its specific, temporal and indispensable functions demonstrated by mouse genetic studies, Hedgehog (Hh) signaling is one of the most potent signaling pathways involved in these processes, but the effect of Hh-signaling activation by small compounds on the repair process had not yet been addressed. Here we examined therapeutic effects of local and one shot-administration of the Hh agonist known as smoothened agonist (SAG) on bone fracture healing in a mouse model. A quantitative analysis with three-dimensional micro-computed tomography showed that SAG administration increased the size of both the cartilaginous callus and bony callus at 14 days after the surgery. A histological analysis showed that SAG administration increased the number of cells expressing a proliferation marker and a chondrocyte marker in cartilaginous callus as well as the cells expressing an osteoblast marker in bony callus. These results indicate that the SAG administration resulted in an enhancement of callus formation during bone fracture healing, which is at least in part mediated by an increase in chondrocyte proliferation in cartilaginous callus and the promotion of bone formation in bony callus. Therapeutic strategies with a SAG-mediated protocol may thus be useful for the treatment of bone fractures. - Highlights: • Local administration of a Hh agonist accelerates callus formation. • The Hh agonist administration promotes chondrocyte proliferation in the soft callus. • The Hh agonist administration increases osteoblast formation in the hard callus.

  6. Heterologous Expression in Remodeled C. elegans: A Platform for Monoaminergic Agonist Identification and Anthelmintic Screening.

    Directory of Open Access Journals (Sweden)

    Wenjing Law

    2015-04-01

    Full Text Available Monoamines, such as 5-HT and tyramine (TA, paralyze both free-living and parasitic nematodes when applied exogenously and serotonergic agonists have been used to clear Haemonchus contortus infections in vivo. Since nematode cell lines are not available and animal screening options are limited, we have developed a screening platform to identify monoamine receptor agonists. Key receptors were expressed heterologously in chimeric, genetically-engineered Caenorhabditis elegans, at sites likely to yield robust phenotypes upon agonist stimulation. This approach potentially preserves the unique pharmacologies of the receptors, while including nematode-specific accessory proteins and the nematode cuticle. Importantly, the sensitivity of monoamine-dependent paralysis could be increased dramatically by hypotonic incubation or the use of bus mutants with increased cuticular permeabilities. We have demonstrated that the monoamine-dependent inhibition of key interneurons, cholinergic motor neurons or body wall muscle inhibited locomotion and caused paralysis. Specifically, 5-HT paralyzed C. elegans 5-HT receptor null animals expressing either nematode, insect or human orthologues of a key Gαo-coupled 5-HT1-like receptor in the cholinergic motor neurons. Importantly, 8-OH-DPAT and PAPP, 5-HT receptor agonists, differentially paralyzed the transgenic animals, with 8-OH-DPAT paralyzing mutant animals expressing the human receptor at concentrations well below those affecting its C. elegans or insect orthologues. Similarly, 5-HT and TA paralyzed C. elegans 5-HT or TA receptor null animals, respectively, expressing either C. elegans or H. contortus 5-HT or TA-gated Cl- channels in either C. elegans cholinergic motor neurons or body wall muscles. Together, these data suggest that this heterologous, ectopic expression screening approach will be useful for the identification of agonists for key monoamine receptors from parasites and could have broad application for

  7. Interactions of dopaminergic agonists and antagonists with dopaminergic D3 binding sites in rat striatum. Evidence that [3H]dopamine can label a high affinity agonist-binding state of the D1 dopamine receptor

    International Nuclear Information System (INIS)

    Leff, S.E.; Creese, I.

    1985-01-01

    The interactions of dopaminergic agonists and antagonists with 3 H-agonist labeled D3 dopaminergic binding sites of rat striatum have been characterized by radioligand-binding techniques. When the binding of [ 3 H]dopamine and [ 3 H]apomorphine to D2 dopamine receptors is blocked by the inclusion of D2 selective concentrations of unlabeled spiroperidol or domperidone, these ligands appear to label selectively the previously termed D3 binding site. Antagonist/[ 3 H]dopamine competition curves are of uniformly steep slope (nH . 1.0), suggesting the presence of a single D3 binding site. The relative potencies of antagonists to inhibit D3 specific [ 3 H]dopamine binding are significantly correlated with their potencies to block D1 dopamine receptors as measured by the inhibition of both dopamine-stimulated adenylate cyclase and [ 3 H]flupentixol-binding activities. The affinities of agonists to inhibit D3 specific [ 3 H]dopamine binding are also correlated with estimates of these agonists affinities for the high affinity binding component of agonist/[ 3 H]flupentixol competition curves. Both D3 specific [ 3 H] dopamine binding and the high affinity agonist-binding component of dopamine/[ 3 H]flupentixol competition curves show a similar sensitivity to guanine nucleotides. Taken together, these data strongly suggest that the D3 binding site is related to a high affinity agonist-binding state of the D1 dopamine receptor

  8. Activation of Cyclic AMP Synthesis by Full and Partial Beta-Adrenergic Receptor Agonists in Chicken Skeletal Muscle Cells

    Science.gov (United States)

    Young, R. B.; Bridge, K. Y.

    2003-01-01

    Several beta-adrenergic receptor (bAR) agonists are known to cause hypertrophy of skeletal muscle tissue. Accordingly, five bAR agonists encompassing a range in activity from strong to weak were evaluated for their ability to stimulate CAMP accumulation in embryonic chicken skeletal muscle cells in culture. Two strong agonists (epinephrine and isoproterenol), one moderate agonist (albuterol), and two weak agonists known to cause hypertrophy in animals (clenbuterol and cimaterol) were studied. Dose response curves were determined over six orders of magnitude in concentration for each agonist, and values were determined for their maximum stimulation of CAMP synthesis rate (Bmax) and the agonist concentration at which 50% stimulation of CAMP synthesis (EC50) occurred. Bmax values decreased in the following order: isoproterenol, epinephrine, albuterol, cimaterol, clenbuterol. Cimaterol and clenbuterol at their Bmax concentrations were approximately 15-fold weaker than isoproterenol in stimulating the rate of CAMP synthesis. When cimaterol and clenbuterol were added to culture media at concentrations known to cause significant muscle hypertrophy in animals, there was no detectable effect on stimulation of CAMP synthesis. Finally, these same levels of cimaterol and clenbuterol did not antagonize the stimulation of CAMP by either epinephrine or isoproterenol.

  9. Evaluation of Mucociliary Clearance by Three Dimension Micro-CT-SPECT in Guinea Pig: Role of Bitter Taste Agonists.

    Science.gov (United States)

    Ortiz, Jose Luis; Ortiz, Amparo; Milara, Javier; Armengot, Miguel; Sanz, Celia; Compañ, Desamparados; Morcillo, Esteban; Cortijo, Julio

    2016-01-01

    Different image techniques have been used to analyze mucociliary clearance (MCC) in humans, but current small animal MCC analysis using in vivo imaging has not been well defined. Bitter taste receptor (T2R) agonists increase ciliary beat frequency (CBF) and cause bronchodilation but their effects in vivo are not well understood. This work analyzes in vivo nasal and bronchial MCC in guinea pig animals using three dimension (3D) micro-CT-SPECT images and evaluates the effect of T2R agonists. Intranasal macroaggreggates of albumin-Technetium 99 metastable (MAA-Tc99m) and lung nebulized Tc99m albumin nanocolloids were used to analyze the effect of T2R agonists on nasal and bronchial MCC respectively, using 3D micro-CT-SPECT in guinea pig. MAA-Tc99m showed a nasal mucociliary transport rate of 0.36 mm/min that was increased in presence of T2R agonist to 0.66 mm/min. Tc99m albumin nanocolloids were homogeneously distributed in the lung of guinea pig and cleared with time-dependence through the bronchi and trachea of guinea pig. T2R agonist increased bronchial MCC of Tc99m albumin nanocolloids. T2R agonists increased CBF in human nasal ciliated cells in vitro and induced bronchodilation in human bronchi ex vivo. In summary, T2R agonists increase MCC in vivo as assessed by 3D micro-CT-SPECT analysis.

  10. Interaction between Mu and Delta Opioid Receptor Agonists in an Assay of Capsaicin-Induced Thermal Allodynia in Rhesus Monkeys

    Directory of Open Access Journals (Sweden)

    S. Stevens Negus

    2012-01-01

    Full Text Available Delta opioid agonists enhance antinociceptive effects of mu-opioid agonists in many preclinical assays of acute nociception, but delta/mu interactions in preclinical models of inflammation-associated pain have not been examined. This study examined interactions between the delta agonist SNC80 [(+-4-[(αR-α-((2S,5R-4-allyl-2,5-dimethyl-1-piperazinyl-3-methoxybenzyl]-N,N-diethylbenzamide] and the mu agonist analgesics methadone, morphine, and nalbuphine in an assay of capsaicin-induced thermal allodynia in rhesus monkeys. Thermal allodynia was produced by topical application of capsaicin to the tail. Antiallodynic effects of methadone, morphine, and nalbuphine were evaluated alone or in combination with fixed proportions of SNC80 identical to proportions previously shown to enhance acute thermal antinociceptive effects of these mu agonists in rhesus monkeys (0.9 : 1 SNC80/methadone; 0.29 : 1 SNC80/morphine; 3.6 : 1 SNC80/nalbuphine. Methadone, morphine, and nalbuphine each produced dose-dependent antiallodynia. SNC80 produced partial antiallodynia up to the highest dose tested (5.6 mg/kg. SNC80 produced a modest, enantioselective, and naltrindole-reversible enhancement of methadone-induced antiallodynia. However, SNC80 did not enhance morphine antiallodynia and only weakly enhanced nalbuphine antiallodynia. Overall, SNC80 produced modest or no enhancement of the antiallodynic effects of the three mu agonists evaluated. These results suggest that delta agonist-induced enhancement of mu agonist antiallodynia may be weaker and less reliable than previously demonstrated enhancement of mu agonist acute thermal nociception.

  11. Peroxisome proliferator-activated receptor-gamma agonists suppress tissue factor overexpression in rat balloon injury model with paclitaxel infusion.

    Directory of Open Access Journals (Sweden)

    Jun-Bean Park

    Full Text Available The role and underlying mechanisms of rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPAR-γ agonist, on myocardial infarction are poorly understood. We investigated the effects of this PPAR-γ agonist on the expression of tissue factor (TF, a primary molecule for thrombosis, and elucidated its underlying mechanisms. The PPAR-γ agonist inhibited TF expression in response to TNF-α in human umbilical vein endothelial cells, human monocytic leukemia cell line, and human umbilical arterial smooth muscle cells. The overexpression of TF was mediated by increased phosphorylation of mitogen-activated protein kinase (MAPK, which was blocked by the PPAR-γ agonist. The effective MAPK differed depending on each cell type. Luciferase and ChIP assays showed that transcription factor, activator protein-1 (AP-1, was a pivotal target of the PPAR-γ agonist to lower TF transcription. Intriguingly, two main drugs for drug-eluting stent, paclitaxel or rapamycin, significantly exaggerated thrombin-induced TF expression, which was also effectively blocked by the PPAR-γ agonist in all cell types. This PPAR-γ agonist did not impair TF pathway inhibitor (TFPI in three cell types. In rat balloon injury model (Sprague-Dawley rats, n = 10/group with continuous paclitaxel infusion, the PPAR-γ agonist attenuated TF expression by 70±5% (n = 4; P<0.0001 in injured vasculature. Taken together, rosiglitazone reduced TF expression in three critical cell types involved in vascular thrombus formation via MAPK and AP-1 inhibitions. Also, this PPAR-γ agonist reversed the paclitaxel-induced aggravation of TF expression, which suggests a possibility that the benefits might outweigh its risks in a group of patients with paclitaxel-eluting stent implanted.

  12. Bile acids deoxycholic acid and ursodeoxycholic acid differentially regulate human β-defensin-1 and -2 secretion by colonic epithelial cells.

    Science.gov (United States)

    Lajczak, Natalia K; Saint-Criq, Vinciane; O'Dwyer, Aoife M; Perino, Alessia; Adorini, Luciano; Schoonjans, Kristina; Keely, Stephen J

    2017-09-01

    Bile acids and epithelial-derived human β-defensins (HβDs) are known to be important factors in the regulation of colonic mucosal barrier function and inflammation. We hypothesized that bile acids regulate colonic HβD expression and aimed to test this by investigating the effects of deoxycholic acid (DCA) and ursodeoxycholic acid on the expression and release of HβD1 and HβD2 from colonic epithelial cells and mucosal tissues. DCA (10-150 µM) stimulated the release of both HβD1 and HβD2 from epithelial cell monolayers and human colonic mucosal tissue in vitro In contrast, ursodeoxycholic acid (50-200 µM) inhibited both basal and DCA-induced defensin release. Effects of DCA were mimicked by the Takeda GPCR 5 agonist, INT-777 (50 μM), but not by the farnesoid X receptor agonist, GW4064 (10 μM). INT-777 also stimulated colonic HβD1 and HβD2 release from wild-type, but not Takeda GPCR 5 -/- , mice. DCA stimulated phosphorylation of the p65 subunit of NF-κB, an effect that was attenuated by ursodeoxycholic acid, whereas an NF-κB inhibitor, BMS-345541 (25 μM), inhibited DCA-induced HβD2, but not HβD1, release. We conclude that bile acids can differentially regulate colonic epithelial HβD expression and secretion and discuss the implications of our findings for intestinal health and disease.-Lajczak, N. K., Saint-Criq, V., O'Dwyer, A. M., Perino, A., Adorini, L., Schoonjans, K., Keely, S. J. Bile acids deoxycholic acid and ursodeoxycholic acid differentially regulate human β-defensin-1 and -2 secretion by colonic epithelial cells. © FASEB.

  13. Obeticholic acid protects against carbon tetrachloride-induced acute liver injury and inflammation

    International Nuclear Information System (INIS)

    Zhang, Da-Gang; Zhang, Cheng; Wang, Jun-Xian; Wang, Bi-Wei; Wang, Hua; Zhang, Zhi-Hui; Chen, Yuan-Hua; Lu, Yan; Tao, Li; Wang, Jian-Qing; Chen, Xi; Xu, De-Xiang

    2017-01-01

    The farnesoid X receptor (FXR) is a ligand-activated transcription factor that plays important roles in regulating bile acid homeostasis. The aim of the present study was to investigate the effects of obeticholic acid (OCA), a novel synthetic FXR agonist, carbon tetrachloride (CCl 4 )-induced acute liver injury. Mice were intraperitoneally injected with CCl 4 (0.15 ml/kg). In CCl 4 + OCA group, mice were orally with OCA (5 mg/kg) 48, 24 and 1 h before CCl 4 . As expected, hepatic FXR was activated by OCA. Interestingly, OCA pretreatment alleviated CCl 4 -induced elevation of serum ALT and hepatic necrosis. Moreover, OCA pretreatment inhibited CCl 4 -induced hepatocyte apoptosis. Additional experiment showed that OCA inhibits CCl 4 -induced hepatic chemokine gene Mcp-1, Mip-2 and Kc. Moreover, OCA inhibits CCl 4 -induced hepatic pro-inflammatory gene Tnf-α and Il-1β. By contrast, OCA pretreatment elevated hepatic anti-inflammatory gene Il-4. Further analysis showed that OCA pretreatment inhibited hepatic IκB phosphorylation and blocked nuclear translocation of NF-κB p65 and p50 subunits during CCl 4 -induced acute liver injury. In addition, OCA pretreatment inhibited hepatic Akt, ERK and p38 phosphorylation in CCl 4 -induced acute liver injury. These results suggest that OCA protects against CCl 4 -induced acute liver injury and inflammation. Synthetic FXR agonists may be effective antidotes for hepatic inflammation during acute liver injury. - Highlights: • OCA pretreatment activates hepatic FXR. • FXR activation protects against CCl 4 -induced acute liver injury. • FXR activation inhibits hepatocyte apoptosis during CCl 4 -induced liver injury. • FXR activation differentially regulates hepatic inflammatory genes. • Synthetic FXR agonists are effective antidotes for acute liver injury.

  14. Obeticholic acid protects against carbon tetrachloride-induced acute liver injury and inflammation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Da-Gang [First Affiliated Hospital, Anhui Medical University, Hefei 230022 (China); Zhang, Cheng [Department of Toxicology, Anhui Medical University, Hefei 230032 (China); Wang, Jun-Xian [First Affiliated Hospital, Anhui Medical University, Hefei 230022 (China); Wang, Bi-Wei; Wang, Hua; Zhang, Zhi-Hui; Chen, Yuan-Hua [Department of Toxicology, Anhui Medical University, Hefei 230032 (China); Lu, Yan; Tao, Li; Wang, Jian-Qing [Second Affiliated Hospital, Anhui Medical University, Hefei 230601 (China); Chen, Xi [First Affiliated Hospital, Anhui Medical University, Hefei 230022 (China); Xu, De-Xiang, E-mail: xudex@126.com [Department of Toxicology, Anhui Medical University, Hefei 230032 (China)

    2017-01-01

    The farnesoid X receptor (FXR) is a ligand-activated transcription factor that plays important roles in regulating bile acid homeostasis. The aim of the present study was to investigate the effects of obeticholic acid (OCA), a novel synthetic FXR agonist, carbon tetrachloride (CCl{sub 4})-induced acute liver injury. Mice were intraperitoneally injected with CCl{sub 4} (0.15 ml/kg). In CCl{sub 4} + OCA group, mice were orally with OCA (5 mg/kg) 48, 24 and 1 h before CCl{sub 4}. As expected, hepatic FXR was activated by OCA. Interestingly, OCA pretreatment alleviated CCl{sub 4}-induced elevation of serum ALT and hepatic necrosis. Moreover, OCA pretreatment inhibited CCl{sub 4}-induced hepatocyte apoptosis. Additional experiment showed that OCA inhibits CCl{sub 4}-induced hepatic chemokine gene Mcp-1, Mip-2 and Kc. Moreover, OCA inhibits CCl{sub 4}-induced hepatic pro-inflammatory gene Tnf-α and Il-1β. By contrast, OCA pretreatment elevated hepatic anti-inflammatory gene Il-4. Further analysis showed that OCA pretreatment inhibited hepatic IκB phosphorylation and blocked nuclear translocation of NF-κB p65 and p50 subunits during CCl{sub 4}-induced acute liver injury. In addition, OCA pretreatment inhibited hepatic Akt, ERK and p38 phosphorylation in CCl{sub 4}-induced acute liver injury. These results suggest that OCA protects against CCl{sub 4}-induced acute liver injury and inflammation. Synthetic FXR agonists may be effective antidotes for hepatic inflammation during acute liver injury. - Highlights: • OCA pretreatment activates hepatic FXR. • FXR activation protects against CCl{sub 4}-induced acute liver injury. • FXR activation inhibits hepatocyte apoptosis during CCl{sub 4}-induced liver injury. • FXR activation differentially regulates hepatic inflammatory genes. • Synthetic FXR agonists are effective antidotes for acute liver injury.

  15. The effects of acute multiple intraperitoneal injections of the GABAB receptor agonist baclofen on food intake in rats.

    Science.gov (United States)

    Patel, Sunit M; Ebenezer, Ivor S

    2008-12-28

    This study was undertaken to examine the effects of acute repeated administration of the GABA(B) receptor agonist baclofen on food intake in rats. In Experiment 1, the effects of repeated intraperitoneal (i.p.) injections of the GABA(B) receptor agonist baclofen (1 and 2 mg/kg) at 2 h intervals were investigated on food intake in non-deprived male Wistar rats. Both doses of baclofen significantly increased food intake after the 1st injection (PGABA(B) receptor agonists on food intake and energy homeostasis.

  16. Discovery of a potent and selective free fatty acid receptor 1 agonist with low lipophilicity and high oral bioavailability

    DEFF Research Database (Denmark)

    Christiansen, Elisabeth; Due-Hansen, Maria E; Urban, Christian

    2013-01-01

    The free fatty acid receptor 1 (FFA1, also known as GPR40) mediates enhancement of glucose-stimulated insulin secretion and is emerging as a new target for the treatment of type 2 diabetes. Several FFA1 agonists are known, but the majority of these suffer from high lipophilicity. We have previously...... reported the FFA1 agonist 3 (TUG-424). We here describe the continued structure-activity exploration and optimization of this compound series, leading to the discovery of the more potent agonist 40, a compound with low lipophilicity, excellent in vitro metabolic stability and permeability, complete oral...

  17. Dipeptidyl peptidase-4 (DPP-4) inhibitors are favourable to glucagon-like peptide-1 (GLP-1) agonists

    DEFF Research Database (Denmark)

    Madsbad, Sten

    2012-01-01

    Incretin-based therapies, which include the GLP-1 receptor agonists and DPP-4 inhibitors, use the antidiabetic properties of potentiating the GLP-1 receptor signalling via the regulation of insulin and glucagon secretion, inhibition of gastric emptying and suppression of appetite. Most physicians...... will start antidiabetic treatment with metformin, but adding a GLP-1 receptor agonist as the second drug seems to be optimal since more patients will reach an HbA1c below 7% than with a DPP-4 inhibitor or another oral antidiabetic agents and with minimal risk of hypoglycaemia. The GLP-1 receptor agonists...

  18. Direct assessment of cumulative aryl hydrocarbon receptor agonist activity in sera from experimentally exposed mice and environmentally exposed humans

    DEFF Research Database (Denmark)

    Schlezinger, Jennifer J; Bernard, Pamela L; Haas, Amelia

    2010-01-01

    (PCB)-exposed Faroe Islanders using an AhR-driven reporter cell line. To validate relationships between serum AhR agonist levels and biological outcomes, AhR agonist activity in mouse sera correlated with toxic end points. AhR agonist activity in unmanipulated ("neat") human sera was compared......, was associated with the frequency of recent pilot whale dinners, but did not correlate with levels of PCBs quantified by GC/MS. Surprisingly, significant "baseline" AhR activity was found in commercial human sera. CONCLUSIONS: An AhR reporter assay revealed cumulative levels of AhR activation potential in neat...

  19. Glucagon-like peptide-1 receptor agonists for the treatment of type 2 diabetes

    DEFF Research Database (Denmark)

    Lund, Asger; Knop, Filip K; Vilsbøll, Tina

    2014-01-01

    Glucagon-like peptide-1 (GLP-1) is a gastrointestinal hormone, secreted in response to ingestion of nutrients, and has important effects on several of the pathophysiological features of type 2 diabetes (T2D). The effects include potentiation of insulin secretion, suppression of glucagon secretion...... effects. This review gives an overview of the clinical data on GLP-1R agonists that have been compared in head-to-head studies and focuses on relevant differences between the compounds. Highlighting these similarities and differences could be beneficial for physicians in choosing the best treatment......, slowing of gastric emptying and suppression of appetite. In circulation, GLP-1 has a half-life of approximately 2min due to rapid degradation by the enzyme dipeptidyl peptidase 4 (DPP-4). Because of this short half-life GLP-1 receptor (GLP-1R) agonists, resistant to degradation by DPP-4 have been...

  20. Treatment of type 2 diabetes with glucagon-like peptide-1 receptor agonists

    DEFF Research Database (Denmark)

    Hansen, K B; Knop, F K; Holst, Jens Juul

    2009-01-01

    of hypoglycaemia with GLP-1 receptor agonists is low, the compounds have clinically relevant effects on body weight, and data are suggesting beneficial effects on cardiovascular risk factors. Exenatide was released in 2005 for the treatment of type 2 diabetes and liraglutide is expected to be approved by the Food......The incretin system is an area of great interest for the development of new therapies for the management of type 2 diabetes. Existing antidiabetic drugs are often insufficient at getting patients to glycaemic goals. Furthermore, current treatment modalities are not able to prevent the continued...... ongoing decline in pancreatic beta-cell function and, lastly, they have a number of side effects including hypoglycaemia and weight gain. Glucagon-like peptide-1 (GLP-1) receptor agonists are a new class of pharmacological agents, which improve glucose homeostasis in a multifaceted way. Their effects...

  1. Guanine nucleotide regulation of dopamine receptor agonist affinity states in rat estradiol-induced pituitary tumors

    Energy Technology Data Exchange (ETDEWEB)

    Di Paolo, T.; Falardeau, P.

    1987-08-31

    The authors have investigated dopamine (DA) receptor agonist high- and low-affinity states in female rate estradiol-induced prolactin (PRL)-secreting pituitary tumors and intact pituitary tissue. Estradiol treatment increased the anterior pituitary weight 9-fold and plasma prolactin levels 74-fold and these measures are correlated (R = 0.745, n = 73, p < 0.001). Competition for (/sup 3/H)-spiperone binding to the DA receptor by apomorphine was compared in normal and adenomatous pituitary tissue. The inhibition constants (Ki) and the proportions of the two apomorphine sites are unchanged in tumors compared to intact pituitary tissue. Guanosine 5'-(..beta..-..gamma..-imino)triphosphate (Gpp(NH)p) causes complete conversion of the high into low affinity dopaminergic agonist site in normal pituitary and in tumors. These results suggest that rats with primary estradiol-induced pituitary tumors have normal and functional DA receptors. 9 references, 2 tables.

  2. Guanine nucleotide regulation of dopamine receptor agonist affinity states in rat estradiol-induced pituitary tumors

    International Nuclear Information System (INIS)

    Di Paolo, T.; Falardeau, P.

    1987-01-01

    The authors have investigated dopamine (DA) receptor agonist high- and low-affinity states in female rate estradiol-induced prolactin (PRL)-secreting pituitary tumors and intact pituitary tissue. Estradiol treatment increased the anterior pituitary weight 9-fold and plasma prolactin levels 74-fold and these measures are correlated (R = 0.745, n = 73, p 3 H]-spiperone binding to the DA receptor by apomorphine was compared in normal and adenomatous pituitary tissue. The inhibition constants (Ki) and the proportions of the two apomorphine sites are unchanged in tumors compared to intact pituitary tissue. Guanosine 5'-[β-γ-imino]triphosphate (Gpp(NH)p) causes complete conversion of the high into low affinity dopaminergic agonist site in normal pituitary and in tumors. These results suggest that rats with primary estradiol-induced pituitary tumors have normal and functional DA receptors. 9 references, 2 tables

  3. Sphingosine-1-Phosphate Receptor-1 Selective Agonist Enhances Collateral Growth and Protects against Subsequent Stroke.

    Directory of Open Access Journals (Sweden)

    Masahiko Ichijo

    Full Text Available Collateral growth after acute occlusion of an intracranial artery is triggered by increasing shear stress in preexisting collateral pathways. Recently, sphingosine-1-phosphate receptor-1 (S1PR1 on endothelial cells was reported to be essential in sensing fluid shear stress. Here, we evaluated the expression of S1PR1 in the hypoperfused mouse brain and investigated the effect of a selective S1PR1 agonist on leptomeningeal collateral growth and subsequent ischemic damage after focal ischemia.In C57Bl/6 mice (n = 133 subjected to unilateral common carotid occlusion (CCAO and sham surgery. The first series examined the time course of collateral growth, cell proliferation, and S1PR1 expression in the leptomeningeal arteries after CCAO. The second series examined the relationship between pharmacological regulation of S1PR1 and collateral growth of leptomeningeal anastomoses. Animals were randomly assigned to one of the following groups: LtCCAO and daily intraperitoneal (i.p. injection for 7 days of an S1PR1 selective agonist (SEW2871, 5 mg/kg/day; sham surgery and daily i.p. injection for 7 days of SEW2871 after surgery; LtCCAO and daily i.p. injection for 7 days of SEW2871 and an S1PR1 inverse agonist (VPC23019, 0.5 mg/kg; LtCCAO and daily i.p. injection of DMSO for 7 days after surgery; and sham surgery and daily i.p. injection of DMSO for 7 days. Leptomeningeal anastomoses were visualized 14 days after LtCCAO by latex perfusion method, and a set of animals underwent subsequent permanent middle cerebral artery occlusion (pMCAO 7 days after the treatment termination. Neurological functions 1 hour, 1, 4, and 7 days and infarction volume 7 days after pMCAO were evaluated.In parallel with the increase in S1PR1 mRNA levels, S1PR1 expression colocalized with endothelial cell markers in the leptomeningeal arteries, increased markedly on the side of the CCAO, and peaked 7 days after CCAO. Mitotic cell numbers in the leptomeningeal arteries increased after

  4. Quantitative phosphoproteomics dissection of 7TM receptor signaling using full and biased agonists

    DEFF Research Database (Denmark)

    Christensen, Gitte L; Kelstrup, Christian D; Lyngsø, Christina

    2010-01-01

    only activates the Gaq protein-independent signaling.e quantified more than ten thousand phosphorylation sites of which 1183 were regulated by Angiotensin II or its analogue SII Angiotensin II. 36% of the AT1R regulated phosphorylations were regulated by SII Angiotensin II. Analysis of phosphorylation...... into Angiotensin II signal transduction and is the first study dissecting the differences between a full agonist and a biased agonist from a 7TMR on a systems-wide scale. Importantly, it reveals a previously unappreciated diversity and quantity of Gaq protein-independent signaling and uncovers novel signaling......Seven-transmembrane receptors (7TMRs) signal through the well described heterotrimeric G proteins, but can also activate G protein-independent signaling pathways of which the impact and complexity are less understood. The Angiotensin II type 1 receptor (AT1R) is a prototypical 7TMR and an important...

  5. Quantitative phosphoproteomics dissection of seven-transmembrane receptor signaling using full and biased agonists

    DEFF Research Database (Denmark)

    Christensen, Gitte L; Kelstrup, Christian D; Lyngsø, Christina

    2010-01-01

    (q)-dependent and -independent AT(1)R signaling. This study provides substantial novel insight into angiotensin II signal transduction and is the first study dissecting the differences between a full agonist and a biased agonist from a 7TMR on a systems-wide scale. Importantly, it reveals a previously unappreciated diversity......Seven-transmembrane receptors (7TMRs) signal through the well described heterotrimeric G proteins but can also activate G protein-independent signaling pathways of which the impact and complexity are less understood. The angiotensin II type 1 receptor (AT(1)R) is a prototypical 7TMR...... and quantity of Galpha(q) protein-independent signaling and uncovers novel signaling pathways. We foresee that the amount and diversity of G protein-independent signaling may be more pronounced than previously recognized for other 7TMRs as well. Quantitative mass spectrometry is a promising tool for evaluation...

  6. Successful treatment of dopamine dysregulation syndrome with dopamine D2 partial agonist antipsychotic drug

    Directory of Open Access Journals (Sweden)

    Mizushima Jin

    2012-07-01

    Full Text Available Abstract Dopamine dysregulation syndrome (DDS consists of a series of complications such as compulsive use of dopaminergic medications, aggressive or hypomanic behaviors during excessive use, and withdrawal states characterized by dysphoria and anxiety, caused by long-term dopaminergic treatment in patients with Parkinson’s disease (PD. Although several ways to manage DDS have been suggested, there has been no established treatment that can manage DDS without deterioration of motor symptoms. In this article, we present a case of PD in whom the administration of the dopamine D2 partial agonistic antipsychotic drug aripiprazole improved DDS symptoms such as craving and compulsive behavior without worsening of motor symptoms. Considering the profile of this drug as a partial agonist at D2 receptors, it is possible that it exerts its therapeutic effect on DDS by modulating the dysfunctional dopamine system.

  7. High constitutive signaling of the ghrelin receptor--identification of a potent inverse agonist

    DEFF Research Database (Denmark)

    Holst, Birgitte; Cygankiewicz, Adam; Jensen, Tine Halkjaer

    2003-01-01

    Ghrelin is a GH-releasing peptide that also has an important role as an orexigenic hormone-stimulating food intake. By measuring inositol phosphate turnover or by using a reporter assay for transcriptional activity controlled by cAMP-responsive elements, the ghrelin receptor showed strong, ligand......-independent signaling in transfected COS-7 or human embryonic kidney 293 cells. Ghrelin and a number of the known nonpeptide GH secretagogues acted as agonists stimulating inositol phosphate turnover further. In contrast, the low potency ghrelin antagonist, [D-Arg1,D-Phe5,D-Trp7,9,Leu11]-substance P was surprisingly...... found to be a high potency (EC50 = 5.2 nm) full inverse agonist as it decreased the constitutive signaling of the ghrelin receptor down to that observed in untransfected cells. The homologous motilin receptor functioned as a negative control as it did not display any sign of constitutive activity...

  8. Electrophysiological actions of GABAB agonists and antagonists in rat dorso-lateral septal neurones in vitro.

    Science.gov (United States)

    Bon, C; Galvan, M

    1996-06-01

    1. The actions of GABAB-receptor agonists and antagonists on rat dorso-lateral septal neurones in vitro were recorded with intracellular microelectrodes. 2. In the presence of 1 microM tetrodotoxin to prevent indirect neuronal effects caused by action potential-dependent neurotransmitter release, bath application of baclofen (0.1-30 microM) or SK&F 97541 (0.01-3 microM) evoked concentration-dependent hyperpolarizations which reversed close to the potassium equilibrium potential; the EC50S were 0.55 and 0.05 microM, respectively. No significant desensitization was observed during prolonged agonist exposure (dorso-lateral septal nucleus express conventional GABAB receptors, which are involved in the generation of slow inhibitory postsynaptic potentials. CGP 55845A is the most potent GABAB receptor antagonist described in this brain area.

  9. Liver X Receptor Agonists Inhibit the Phospholipid Regulatory Gene CTP: Phosphoethanolamine Cytidylyltransferase-Pcyt2

    Directory of Open Access Journals (Sweden)

    Lin Zhu

    2008-01-01

    Full Text Available Metabolic pulse-chase experiments demonstrated that 25-hydroxycholesterol (25-OH, the endogenous activator of the liver X receptor (LXR, significantly reduced the biosynthesis of phosphatidylethanolamine via CDP-ethanolamine (Kennedy pathway at the step catalyzed by CTP: phosphoethanolamine cytidylyltransferase (Pcyt2. In the mouse embryonic fibroblasts C3H10T1/2, the LXR synthetic agonist TO901317 lowered Pcyt2 promoter-luciferase activity in a concentration-dependent manner. Furthermore, 25-OH and TO901317 reduced mouse Pcyt2 mRNA and protein levels by 35–60%. The inhibitory effects of oxysterols and TO901317 on the Pcyt2 promoter function, mRNA and protein expression were conserved in the human breast cancer cells MCF-7. These studies identify the Pcyt2 gene as a novel target whereby LXR agonists may indirectly modulate inflammatory responses and atherosclerosis.

  10. Therapeutic Effects of Melatonin Receptor Agonists on Sleep and Comorbid Disorders

    Directory of Open Access Journals (Sweden)

    Moshe Laudon

    2014-09-01

    Full Text Available Several melatonin receptors agonists (ramelteon, prolonged-release melatonin, agomelatine and tasimelteon have recently become available for the treatment of insomnia, depression and circadian rhythms sleep-wake disorders. The efficacy and safety profiles of these compounds in the treatment of the indicated disorders are reviewed. Accumulating evidence indicates that sleep-wake disorders and co-existing medical conditions are mutually exacerbating. This understanding has now been incorporated into the new Diagnostic and Statistical Manual of Mental Disorders, 5th Edition (DSM-5. Therefore, when evaluating the risk/benefit ratio of sleep drugs, it is pertinent to also evaluate their effects on wake and comorbid condition. Beneficial effects of melatonin receptor agonists on comorbid neurological, psychiatric, cardiovascular and metabolic symptomatology beyond sleep regulation are also described. The review underlines the beneficial value of enhancing physiological sleep in comorbid conditions.

  11. Alpha-2 receptor agonists for the treatment of posttraumatic stress disorder

    Directory of Open Access Journals (Sweden)

    Molly R Belkin

    2017-09-01

    Full Text Available Clonidine and guanfacine are alpha-2 receptor agonists that decrease sympathetic outflow from the central nervous system. Posttraumatic stress disorder (PTSD is an anxiety disorder that is theorized to be related to a hyperactive sympathetic nervous system. Currently, the only US Food and Drug Administration (FDA-approved medications for PTSD are the selective serotonin reuptake inhibitors (SSRIs sertraline and paroxetine. Sometimes use of the SSRIs may not lead to full remission and symptoms of hyperarousal often persist. This article specifically reviews the literature on alpha-2 receptor agonist use for the treatment of PTSD and concludes that while the evidence base is limited, these agents might be considered useful when SSRIs fail to treat symptoms of agitation and hyperarousal in patients with PTSD.

  12. A Novel Non-Peptidic Agonist of the Ghrelin Receptor with Orexigenic Activity In vivo

    Science.gov (United States)

    Pastor-Cavada, Elena; Pardo, Leticia M.; Kandil, Dalia; Torres-Fuentes, Cristina; Clarke, Sarah L.; Shaban, Hamdy; McGlacken, Gerard P.; Schellekens, Harriet

    2016-11-01

    Loss of appetite in the medically ill and ageing populations is a major health problem and a significant symptom in cachexia syndromes, which is the loss of muscle and fat mass. Ghrelin is a gut-derived hormone which can stimulate appetite. Herein we describe a novel, simple, non-peptidic, 2-pyridone which acts as a selective agonist for the ghrelin receptor (GHS-R1a). The small 2-pyridone demonstrated clear agonistic activity in both transfected human cells and mouse hypothalamic cells with endogenous GHS-R1a receptor expression. In vivo tests with the hit compound showed significant increased food intake following peripheral administration, which highlights the potent orexigenic effect of this novel GHS-R1a receptor ligand.

  13. Transcriptomic and phenotypic profiling in developing zebrafish exposed to thyroid hormone receptor agonists

    Energy Technology Data Exchange (ETDEWEB)

    Haggard, Derik E.; Noyes, Pamela D.; Waters, Katrina M.; Tanguay, Robert L.

    2018-04-01

    There is a need to develop novel, high-throughput screening and prioritization methods to identify chemicals with adverse estrogen, androgen, and thyroid activity to protect human health and the environment and is of interest to the Endocrine Disruptor Screening Program. The current aim is to explore the utility of zebrafish as a testing paradigm to classify endocrine activity using phenotypically anchored transcriptome profiling. Transcriptome analysis was conducted on embryos exposed to 25 estrogen-, androgen-, or thyroid-active chemicals at a concentration that elicited adverse malformations or mortality at 120 hours post-fertilization in 80% of the animals exposed. Analysis of the top 1000 significant differentially expressed transcripts across all treatments identified a unique transcriptional and phenotypic profile for thyroid hormone receptor agonists, which can be used as a biomarker screen for potential thyroid hormone agonists.

  14. Differential effects of beta-adrenoceptor partial agonists in patients with postural hypotension

    DEFF Research Database (Denmark)

    Mehlsen, J; Stadeager, C; Trap-Jensen, J

    1993-01-01

    patients with postural hypotension of different aetiologies. Blood pressure, heart rate and stroke volume were measured in the supine and head-up tilted positions. Left ventricular ejection fraction (LVEF) was measured in the supine position, and vascular resistance, left ventricular volume, and left.......min-1 and LVEF from 0.57 to 0.52, and reduced mean arterial blood pressure from 103 mm Hg to 93 mm Hg. Xamoterol showed beta-adrenoceptor agonistic effects in the supine position through increments in heart rate from 72 to 90 beats.min-1 and LVEF from 0.58 to 0.66, and raised mean arterial blood...... pressure from 108 to 123 mm Hg. It is concluded that the degree of agonist activity of a beta-adrenergic agent is of importance if it is given to a patient with postural hypotension....

  15. Clonazepam as Agonist Substitution Treatment for Benzodiazepine Dependence: A Case Report

    Directory of Open Access Journals (Sweden)

    Angelo Giovanni Icro Maremmani

    2013-01-01

    Full Text Available Nowadays, the misuse of benzodiazepines (BZDs is a cause for a serious concern among pharmacologically inexperienced patients, whether treated or untreated, that could lead to significant complications, including tolerance, dependence, and addiction. We present a case report in which an Italian patient affected by anxiety disorder and treated with BZDs presented a severe case of dependence on BZDs. We treated him according to an agonist substitution approach, switching from the abused BZD to a slow-onset, long-acting, high potency agonist (clonazepam, and looking at the methadone treatment model as paradigm. We decided to use clonazepam for its pharmacokinetic properties. The advantage of choosing a slow-onset, long-lasting BZD for the treatment of our patient was that it led us to a remarkable improvement in the clinical situation, including the cessation of craving, absence of withdrawal symptoms, reduced anxiety, improvements in social functioning, and a better cognition level.

  16. Regulation of pyruvate dehydrogenase kinase expression by the farnesoid X receptor

    International Nuclear Information System (INIS)

    Savkur, Rajesh S.; Bramlett, Kelli S.; Michael, Laura F.; Burris, Thomas P.

    2005-01-01

    The pyruvate dehydrogenase complex (PDC) functions as an important junction in intermediary metabolism by influencing the utilization of fat versus carbohydrate as a source of fuel. Activation of PDC is achieved by phosphatases, whereas, inactivation is catalyzed by pyruvate dehydrogenase kinases (PDKs). The expression of PDK4 is highly regulated by the glucocorticoid and peroxisome proliferator-activated receptors. We demonstrate that the farnesoid X receptor (FXR; NR1H4), which regulates a variety of genes involved in lipoprotein metabolism, also regulates the expression of PDK4. Treatment of rat hepatoma cells as well as human primary hepatocytes with FXR agonists stimulates the expression of PDK4 to levels comparable to those obtained with glucocorticoids. In addition, treatment of mice with an FXR agonist significantly increased hepatic PDK4 expression, while concomitantly decreasing plasma triglyceride levels. Thus, activation of FXR may suppress glycolysis and enhance oxidation of fatty acids via inactivation of the PDC by increasing PDK4 expression

  17. Effect of skin temperature on cutaneous vasodilator response to the β-adrenergic agonist isoproterenol

    OpenAIRE

    Hodges, Gary J.; Kellogg, Dean L.; Johnson, John M.

    2015-01-01

    The vascular response to local skin cooling is dependent in part on a cold-induced translocation of α2C-receptors and an increased α-adrenoreceptor function. To discover whether β-adrenergic function might contribute, we examined whether β-receptor sensitivity to the β-agonist isoproterenol was affected by local skin temperature. In seven healthy volunteers, skin blood flow was measured from the forearm by laser-Doppler flowmetry and blood pressure was measured by finger photoplethysmography....

  18. Ghrelin Agonist JMV 1843 Increases Food Intake, Body Weight and Expression of Orexigenic Neuropeptides in Mice

    Czech Academy of Sciences Publication Activity Database

    Holubová, Martina; Špolcová, Andrea; Demianova, Zuzana; Sýkora, D.; Fehrentz, J. A.; Martinez, J.; Štofková, A.; Jurčovičová, J.; Drápalová, J.; Lacinová, Z.; Haluzík, M.; Železná, Blanka; Maletínská, Lenka

    2013-01-01

    Roč. 62, č. 4 (2013), s. 435-444 ISSN 0862-8408 R&D Projects: GA ČR GA303/09/0744; GA ČR GAP303/10/1368 Institutional support: RVO:61388963 Keywords : GHS-R agonists * JMV 1843 * male C57BL/6 mice * food intake * NPY/AgRP Subject RIV: CE - Biochemistry Impact factor: 1.487, year: 2013

  19. Myotropic Effects of Cholinergic Muscarinic Agonists and Antagonists in the Beetle Tenebrio molitor L.

    Science.gov (United States)

    Chowanski, Szymon; Rosinski, Grzegorz

    2017-01-01

    In mammals, the cholinergic nervous system plays a crucial role in neuronal regulation of physiological processes. It acts on cells by two types of receptors - nicotinic and muscarinic receptors. Both signal transmission pathways also operate in the central and peripheral cholinergic nervous system of insects. In our pharmacological experiments, we studied the effects of two muscarinic agonists (carbachol, pilocarpine) and two muscarinic antagonists (atropine, scopolamine) on the muscle contractile activity of visceral organs in the beetle, Tenebrio molitor. Both antagonists, when injected to haemolymph at concentration 10-5 M, caused delayed and prolonged cardioinhibitory effects on heart contractility in ortho- and antidromic phases of heart activity in T. molitor pupa what was observed as negative chrono- and inotropic effects. Agonist of muscarinic receptors - carbachol evoked opposite effect and increased contraction rate but only in antidromic phase. Pilocarpine, the second agonist induced weak negative chronotropic effects in the antiand orthodromic phases of heart activity. However, neither agonists had an effect on semi-isolated beetle heart in vitro. Only atropine at the highest tested concentrations slightly decreased the frequency of myocardial contractions. These suggest the regulation of heart activity by muscarinic system indirectly. The tested compounds also affected the contractility of the oviduct and hindgut, but the responses of these organs were varied and depended on the concentration of the applied compounds. These pharmacological experiments suggest the possible modulation of insect visceral muscle contractility by the cholinergic nervous system and indirectly indicate the presence of muscarinic receptor(s) in the visceral organs of the beetle T. molitor. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  20. Differential activation of G-proteins by μ-opioid receptor agonists

    Science.gov (United States)

    Saidak, Zuzana; Blake-Palmer, Katherine; Hay, Debbie L; Northup, John K; Glass, Michelle

    2006-01-01

    We investigated the ability of the activated μ-opioid receptor (MOR) to differentiate between myristoylated Gαi1 and GαoA type Gα proteins, and the maximal activity of a range of synthetic and endogenous agonists to activate each Gα protein. Membranes from HEK293 cells stably expressing transfected MOR were chaotrope extracted to denature endogenous G-proteins and reconstituted with specific purified G-proteins. The Gα subunits were generated in bacteria and were demonstrated to be recognised equivalently to bovine brain purified Gα protein by CB1 cannabinoid receptors. The ability of agonists to catalyse the MOR-dependent GDP/[35S]GTPγS exchange was then compared for Gαi1 and GαoA. Activation of MOR by DAMGO produced a high-affinity saturable interaction for GαoA (Km=20±1 nM) but a low-affinity interaction with Gαi1 (Km=116±12 nM). DAMGO, met-enkephalin and leucine-enkephalin displayed maximal Gα activation among the agonists evaluated. Endomorphins 1 and 2, methadone and β-endorphin activated both Gα to more than 75% of the maximal response, whereas fentanyl partially activated both G-proteins. Buprenorphine and morphine demonstrated a statistically significant difference between the maximal activities between Gαi1 and GαoA. Interestingly, DAMGO, morphine, endomorphins 1 and 2, displayed significant differences in the potencies for the activation of the two Gα. Differences in maximal activity and potency, for Gαi1 versus GαoA, are both indicative of agonist selective activation of G-proteins in response to MOR activation. These findings may provide a starting point for the design of drugs that demonstrate greater selectivity between these two G-proteins and therefore produce a more limited range of effects. PMID:16415903

  1. Chronic exposure to dopamine agonists affects the integrity of striatal D2 receptors in Parkinson's patients

    Directory of Open Access Journals (Sweden)

    Marios Politis

    2017-01-01

    Full Text Available We aimed to investigate the integrity and clinical relevance of striatal dopamine receptor type-2 (D2R availability in Parkinson's disease (PD patients. We studied 68 PD patients, spanning from early to advanced disease stages, and 12 healthy controls. All participants received one [11C]raclopride PET scan in an OFF medication condition for quantification of striatal D2R availability in vivo. Parametric images of [11C]raclopride non-displaceable binding potential were generated from the dynamic [11C]raclopride scans using implementation of the simplified reference tissue model with cerebellum as the reference tissue. PET data were interrogated for correlations with clinical data related to disease burden and dopaminergic treatment. PD patients showed a mean 16.7% decrease in caudate D2R and a mean 3.5% increase in putaminal D2R availability compared to healthy controls. Lower caudate [11C]raclopride BPND correlated with longer PD duration. PD patients on dopamine agonist treatment had 9.2% reduced D2R availability in the caudate and 12.8% in the putamen compared to PD patients who never received treatment with dopamine agonists. Higher amounts of lifetime dopamine agonist therapy correlated with reduced D2Rs availability in both caudate and putamen. No associations between striatal D2R availability and levodopa treatment and dyskinesias were found. In advancing PD the caudate and putamen D2R availability are differentially affected. Chronic exposure to treatment with dopamine agonists, but no levodopa, suppresses striatal D2R availability, which may have relevance to output signaling to frontal lobes and the occurrence of executive deficits, but not dyskinesias.

  2. Development of CINPA1 analogs as novel and potent inverse agonists of constitutive androstane receptor

    OpenAIRE

    Lin, Wenwei; Yang, Lei; Chai, Sergio C.; Lu, Yan; Chen, Taosheng

    2015-01-01

    Constitutive androstane receptor (CAR, NR1I3) and pregnane X receptor (PXR, NR1I2) are master regulators of endobiotic and xenobiotic metabolism and disposition. Because CAR is constitutively active in certain cellular contexts, inhibiting CAR might reduce drug-induced hepatotoxicity and resensitize drug-resistant cancer cells to chemotherapeutic drugs. We recently reported a novel CAR inhibitor/inverse agonist CINPA1 (11). Here, we have obtained or designed 54 analogs of CINPA1 and used a ti...

  3. Agonist anti-GITR antibody significantly enhances the therapeutic efficacy of Listeria monocytogenes-based immunotherapy.

    Science.gov (United States)

    Shrimali, Rajeev; Ahmad, Shamim; Berrong, Zuzana; Okoev, Grigori; Matevosyan, Adelaida; Razavi, Ghazaleh Shoja E; Petit, Robert; Gupta, Seema; Mkrtichyan, Mikayel; Khleif, Samir N

    2017-08-15

    We previously demonstrated that in addition to generating an antigen-specific immune response, Listeria monocytogenes (Lm)-based immunotherapy significantly reduces the ratio of regulatory T cells (Tregs)/CD4 + and myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment. Since Lm-based immunotherapy is able to inhibit the immune suppressive environment, we hypothesized that combining this treatment with agonist antibody to a co-stimulatory receptor that would further boost the effector arm of immunity will result in significant improvement of anti-tumor efficacy of treatment. Here we tested the immune and therapeutic efficacy of Listeria-based immunotherapy combination with agonist antibody to glucocorticoid-induced tumor necrosis factor receptor-related protein (GITR) in TC-1 mouse tumor model. We evaluated the potency of combination on tumor growth and survival of treated animals and profiled tumor microenvironment for effector and suppressor cell populations. We demonstrate that combination of Listeria-based immunotherapy with agonist antibody to GITR synergizes to improve immune and therapeutic efficacy of treatment in a mouse tumor model. We show that this combinational treatment leads to significant inhibition of tumor-growth, prolongs survival and leads to complete regression of established tumors in 60% of treated animals. We determined that this therapeutic benefit of combinational treatment is due to a significant increase in tumor infiltrating effector CD4 + and CD8 + T cells along with a decrease of inhibitory cells. To our knowledge, this is the first study that exploits Lm-based immunotherapy combined with agonist anti-GITR antibody as a potent treatment strategy that simultaneously targets both the effector and suppressor arms of the immune system, leading to significantly improved anti-tumor efficacy. We believe that our findings depicted in this manuscript provide a promising and translatable strategy that can enhance the overall

  4. SB265610 is an allosteric, inverse agonist at the human CXCR2 receptor

    Science.gov (United States)

    Bradley, ME; Bond, ME; Manini, J; Brown, Z; Charlton, SJ

    2009-01-01

    Background and purpose: In several previous studies, the C-X-C chemokine receptor (CXCR)2 antagonist 1-(2-bromo-phenyl)-3-(7-cyano-3H-benzotriazol-4-yl)-urea (SB265610) has been described as binding competitively with the endogenous agonist. This is in contrast to many other chemokine receptor antagonists, where the mechanism of antagonism has been described as allosteric. Experimental approach: To determine whether it displays a unique mechanism among the chemokine receptor antagonists, the mode of action of SB265610 was investigated at the CXCR2 receptor using radioligand and [35S]-GTPγS binding approaches in addition to chemotaxis of human neutrophils. Key results: In equilibrium saturation binding studies, SB265610 depressed the maximal binding of [125I]-interleukin-8 ([125I]-IL-8) without affecting the Kd. In contrast, IL-8 was unable to prevent binding of [3H]-SB265610. Kinetic binding experiments demonstrated that this was not an artefact of irreversible or slowly reversible binding. In functional experiments, SB265610 caused a rightward shift of the concentration-response curves to IL-8 and growth-related oncogene α, but also a reduction in maximal response elicited by each agonist. Fitting these data to an operational allosteric ternary complex model suggested that, once bound, SB265610 completely blocks receptor activation. SB265610 also inhibited basal [35S]-GTPγS binding in this preparation. Conclusions and implications: Taken together, these data suggest that SB265610 behaves as an allosteric inverse agonist at the CXCR2 receptor, binding at a region distinct from the agonist binding site to prevent receptor activation, possibly by interfering with G protein coupling. PMID:19422399

  5. Serotonin(4) (5-HT(4)) receptor agonists are putative antidepressants with a rapid onset of action

    DEFF Research Database (Denmark)

    Lucas, Guillaume; Rymar, Vladimir V; Du, Jenny

    2007-01-01

    parameters considered to be key markers of antidepressant action, but that are observed only after 2-3 week treatments with classical molecules: desensitization of 5-HT(1A) autoreceptors, increased tonus on hippocampal postsynaptic 5-HT(1A) receptors, and enhanced phosphorylation of the CREB protein...... intake consecutive to a chronic mild stress. These findings point out 5-HT(4) receptor agonists as a putative class of antidepressants with a rapid onset of action. Udgivelsesdato: 2007-Sep-6...

  6. Classical and atypical agonists activate M1 muscarinic acetylcholine receptors through common mechanisms

    Czech Academy of Sciences Publication Activity Database

    Randáková, Alena; Dolejší, Eva; Rudajev, Vladimír; Zimčík, Pavel; Doležal, Vladimír; El-Fakahany, E. E.; Jakubík, Jan

    2015-01-01

    Roč. 97, Jul 2015 (2015), s. 27-39 ISSN 1043-6618 R&D Projects: GA ČR(CZ) GA305/09/0681; GA ČR(CZ) GBP304/12/G069; GA MŠk(CZ) EE2.3.30.0025 Institutional support: RVO:67985823 Keywords : muscarinic acetylcholine receptors * atypical agonists * xanomeline * activation mechanism Subject RIV: ED - Physiology Impact factor: 4.816, year: 2015

  7. NeuroD Modulates Opioid Agonist-Selective Regulation of Adult Neurogenesis and Contextual Memory Extinction

    OpenAIRE

    Zheng, Hui; Zhang, Yue; Li, Wen; Loh, Horace H; Law, Ping-Yee

    2013-01-01

    Addictive drugs, including opioids, modulate adult neurogenesis. In order to delineate the probable implications of neurogenesis on contextual memory associated with addiction, we investigated opioid agonist-selective regulation of neurogenic differentiation 1 (NeuroD) activities under the conditioned place preference (CPP) paradigm. Training mice with equivalent doses of morphine and fentanyl produced different CPP extinction rates without measurable differences in the CPP acquisition rate o...

  8. Working memory span capacity improved by a D2 but not D1 receptor family agonist.

    Science.gov (United States)

    Tarantino, Isadore S; Sharp, Richard F; Geyer, Mark A; Meves, Jessica M; Young, Jared W

    2011-06-01

    Patients with schizophrenia exhibit poor working memory (WM). Although several subcomponents of WM can be measured, evidence suggests the primary subcomponent affected in schizophrenia is span capacity (WMC). Indeed, the NIMH-funded MATRICS initiative recommended assaying the WMC when assessing the efficacy of a putative therapeutic for FDA approval. Although dopamine D1 receptor agonists improve delay-dependent memory in animals, evidence for improvements in WMC due to dopamine D1 receptor activation is limited. In contrast, the dopamine D2-family agonist bromocriptine improves WMC in humans. The radial arm maze (RAM) can be used to assess WMC, although complications due to ceiling effects or strategy confounds have limited its use. We describe a 12-arm RAM protocol designed to assess whether the dopamine D1-family agonist SKF 38393 (0, 1, 3, and 10 mg/kg) or bromocriptine (0, 1, 3, and 10 mg/kg) could improve WMC in C57BL/6N mice (n=12) in cross-over designs. WMC increased and strategy usage decreased with training. The dopamine D1 agonist SKF 38393 had no effect on WMC or long-term memory. Bromocriptine decreased WMC errors, without affecting long-term memory, consistent with human studies. These data confirm that WMC can be measured in mice and reveal drug effects that are consistent with reported effects in humans. Future research is warranted to identify the subtype of the D2-family of receptors responsible for the observed improvement in WMC. Finally, this RAM procedure may prove useful in developing animal models of deficient WMC to further assess putative treatments for the cognitive deficits in schizophrenia. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Strategies to improve outcome after islet transplantation using the GLP-1 receptor agonist, extendin-4

    OpenAIRE

    Sharma, Amit

    2007-01-01

    Transplantation of pancreatic islets into the liver via the portal vein has emerged as a treatment option for patients with type I diabetes mellitus. However, loss of functional beta cell mass during isolation and following implantation is a major obstacle in obtaining good long-term results. Exendin-4, a glucagonlike peptide-1 (GLP-1) receptor agonist, improves glucose homeostasis in patients with diabetes. It also has anti-apoptotic and beta cell proliferative properties t...

  10. Prediction of selective estrogen receptor beta agonist using open data and machine learning approach.

    Science.gov (United States)

    Niu, Ai-Qin; Xie, Liang-Jun; Wang, Hui; Zhu, Bing; Wang, Sheng-Qi

    2016-01-01

    Estrogen receptors (ERs) are nuclear transcription factors that are involved in the regulation of many complex physiological processes in humans. ERs have been validated as important drug targets for the treatment of various diseases, including breast cancer, ovarian cancer, osteoporosis, and cardiovascular disease. ERs have two subtypes, ER-α and ER-β. Emerging data suggest that the development of subtype-selective ligands that specifically target ER-β could be a more optimal approach to elicit beneficial estrogen-like activities and reduce side effects. Herein, we focused on ER-β and developed its in silico quantitative structure-activity relationship models using machine learning (ML) methods. The chemical structures and ER-β bioactivity data were extracted from public chemogenomics databases. Four types of popular fingerprint generation methods including MACCS fingerprint, PubChem fingerprint, 2D atom pairs, and Chemistry Development Kit extended fingerprint were used as descriptors. Four ML methods including Naïve Bayesian classifier, k-nearest neighbor, random forest, and support vector machine were used to train the models. The range of classification accuracies was 77.10% to 88.34%, and the range of area under the ROC (receiver operating characteristic) curve values was 0.8151 to 0.9475, evaluated by the 5-fold cross-validation. Comparison analysis suggests that both the random forest and the support vector machine are superior for the classification of selective ER-β agonists. Chemistry Development Kit extended fingerprints and MACCS fingerprint performed better in structural representation between active and inactive agonists. These results demonstrate that combining the fingerprint and ML approaches leads to robust ER-β agonist prediction models, which are potentially applicable to the identification of selective ER-β agonists.

  11. Distinct Signaling Cascades Elicited by Different Formyl Peptide Receptor 2 (FPR2 Agonists

    Directory of Open Access Journals (Sweden)

    Fabio Cattaneo

    2013-04-01

    Full Text Available The formyl peptide receptor 2 (FPR2 is a remarkably versatile transmembrane protein belonging to the G-protein coupled receptor (GPCR family. FPR2 is activated by an array of ligands, which include structurally unrelated lipids and peptide/proteins agonists, resulting in different intracellular responses in a ligand-specific fashion. In addition to the anti-inflammatory lipid, lipoxin A4, several other endogenous agonists also bind FPR2, including serum amyloid A, glucocorticoid-induced annexin 1, urokinase and its receptor, suggesting that the activation of FPR2 may result in potent pro- or anti-inflammatory responses. Other endogenous ligands, also present in biological samples, include resolvins, amyloidogenic proteins, such as beta amyloid (Aβ-42 and prion protein (Prp106–126, the neuroprotective peptide, humanin, antibacterial peptides, annexin 1-derived peptides, chemokine variants, the neuropeptides, vasoactive intestinal peptide (VIP and pituitary adenylate cyclase activating polypeptide (PACAP-27, and mitochondrial peptides. Upon activation, intracellular domains of FPR2 mediate signaling to G-proteins, which trigger several agonist-dependent signal transduction pathways, including activation of phospholipase C (PLC, protein kinase C (PKC isoforms, the phosphoinositide 3-kinase (PI3K/protein kinase B (Akt pathway, the mitogen-activated protein kinase (MAPK pathway, p38MAPK, as well as the phosphorylation of cytosolic tyrosine kinases, tyrosine kinase receptor transactivation, phosphorylation and nuclear translocation of regulatory transcriptional factors, release of calcium and production of oxidants. FPR2 is an attractive therapeutic target, because of its involvement in a range of normal physiological processes and pathological diseases. Here, we review and discuss the most significant findings on the intracellular pathways and on the cross-communication between FPR2 and tyrosine kinase receptors triggered by different FPR2

  12. Characterization of 12 GnRH peptide agonists - a kinetic perspective.

    Science.gov (United States)

    Nederpelt, Indira; Georgi, Victoria; Schiele, Felix; Nowak-Reppel, Katrin; Fernández-Montalván, Amaury E; IJzerman, Adriaan P; Heitman, Laura H

    2016-01-01

    Drug-target residence time is an important, yet often overlooked, parameter in drug discovery. Multiple studies have proposed an increased residence time to be beneficial for improved drug efficacy and/or longer duration of action. Currently, there are many drugs on the market targeting the gonadotropin-releasing hormone (GnRH) receptor for the treatment of hormone-dependent diseases. Surprisingly, the kinetic receptor-binding parameters of these analogues have not yet been reported. Therefore, this project focused on determining the receptor-binding kinetics of 12 GnRH peptide agonists, including many marketed drugs. A novel radioligand-binding competition association assay was developed and optimized for the human GnRH receptor with the use of a radiolabelled peptide agonist, [(125) I]-triptorelin. In addition to radioligand-binding studies, a homogeneous time-resolved FRET Tag-lite™ method was developed as an alternative assay for the same purpose. Two novel competition association assays were successfully developed and applied to determine the kinetic receptor-binding characteristics of 12 high-affinity GnRH peptide agonists. Results obtained from both methods were highly correlated. Interestingly, the binding kinetics of the peptide agonists were more divergent than their affinities with residence times ranging from 5.6 min (goserelin) to 125 min (deslorelin). Our research provides new insights by incorporating kinetic, next to equilibrium, binding parameters in current research and development that can potentially improve future drug discovery targeting the GnRH receptor. © 2015 The British Pharmacological Society.

  13. Differential effects of R-isovaline and the GABAB agonist, baclofen, in the guinea pig ileum.

    Science.gov (United States)

    Fung, Timothy; Asseri, Khalid A; Asiri, Yahya I; Wall, Richard A; Schwarz, Stephan K W; Puil, Ernest; MacLeod, Bernard A

    2016-11-15

    R-isovaline is a non-proteinogenic amino acid which produces analgesia in a range of nociceptive assays. Mediation of this effect by metabotropic receptors for γ-aminobutyric acid (GABA) and glutamate, demonstrated by previous work, may depend on the type of tissue or receptor system. The objective of this study was to assess the activity of R-isovaline acting at GABA B and group II metabotropic glutamate receptors in guinea pig ileum, which is known to exhibit well-defined responses to GABA B agonists such as baclofen. The effects of bath-applied R-isovaline and RS-baclofen were examined on electrically evoked contractions of guinea pig ileum and during GABA B antagonism by CGP52432. In separate experiments, the group II metabotropic glutamate receptor agonist, LY354740 was applied to determine the functional presence of these receptors. R-isovaline (1-100mM) decreased the amplitude of ileal muscle contractions and increased tension. RS-baclofen reduced contraction amplitude, but decreased tension. CGP52432 did not prevent the effects of R-isovaline on contraction amplitude, but antagonized effects of RS-baclofen on contraction amplitude. The group II metabotropic glutamate receptor agonist, LY354740, produced no detectable effects on evoked contractions. R-isovaline differed significantly from RS-baclofen in its actions in the guinea pig ileum, indicated in particular by the finding that CGP52432 blocked only the effects of RS-baclofen. The ileal tissue did not respond to a group II metabotropic glutamate receptor agonist, previously shown to co-mediate R-isovaline analgesia. These findings raise the possibility of a novel therapeutic target at unknown receptors for R-isovaline-like compounds in the guinea pig ileum. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Misoprostol, an anti-ulcer agent and PGE2 receptor agonist, protects against cerebral ischemia

    OpenAIRE

    Li, Jun; Liang, Xibin; Wang, Qian; Breyer, Richard M.; McCullough, Louise; Andreasson, Katrin

    2008-01-01

    Induction of COX-2 activity in cerebral ischemia results in increased neuronal injury and infarct size. Recent studies investigating neurotoxic mechanisms of COX-2 demonstrate both toxic and paradoxically protective effects of downstream prostaglandin receptor signaling pathways. We tested whether misoprostol, a PGE2 receptor agonist that is utilized clinically as an anti-ulcer agent and signals through the protective PGE2 EP2, EP3, and EP4 receptors, would reduce brain injury in the murine m...

  15. Maternal Characteristics of Women Exposed to Hypnotic Benzodiazepine Receptor Agonist during Pregnancy

    OpenAIRE

    Askaa, Bjarke; Jimenez-Solem, Espen; Enghusen Poulsen, Henrik; Traerup Andersen, Jon

    2014-01-01

    Background. There is little knowledge regarding the characteristics of women treated with hypnotic benzodiazepine receptor agonists (HBRAs) during pregnancy. In this large Danish cohort study, we characterize women exposed to HBRA during pregnancy. We determined changes in prevalence of HBRA use from 1997 to 2010 and exposure to HBRAs in relation to pregnancy. Methods. We performed a retrospective cohort study including 911,017 pregnant women in the period from 1997 to 2010. Information was r...

  16. Ghrelin receptor (GHS-R1A) agonists show potential as interventive agents during aging.

    Science.gov (United States)

    Smith, Roy G; Sun, Yuxiang; Jiang, Hong; Albarran-Zeckler, Rosie; Timchenko, Nikolai

    2007-11-01

    Administration of an orally active agonist (MK-0677) of the growth hormone secretagogue receptor (GHS-R1a) to elderly subjects restored the amplitude of endogenous episodic growth hormone (GH) release to that of young adults. Functional benefits include increased lean mass and bone density and modest improvements in strength. In old mice, a similar agonist partially restored function to the thymus and reduced tumor cell growth and metastasis. Treatment of old mice with the endogenous GHS-R1a agonist ghrelin restored a young liver phenotype. The mechanism involves inhibition of cyclin D3:cdk4/cdk6 activity and increased protein phosphatase-2A (PP2A) activity in liver nuclei, which stabilizes the dephosphorylated form of the transcription factor C/EBPalpha preventing the age-dependent formation of the C/EBPalpha-Rb-E2F4-Brm nuclear complex. By inhibiting formation of this complex, repression of E2F target genes is de-repressed and C/EBPalpha regulated expression of Pepck, a regulator of gluconeogenesis, is normalized, thereby restoring a young liver phenotype. In the brain, aging is associated with decline in dopamine function. We investigated the potential neuromodulatory role of GHS-R1a on dopamine action. Neurons were identified in the hippocampus, cortex, substantia nigra, and ventral tegmental areas that coexpressed GHS-R1a and dopamine receptor subtype-1 (D1R). Cell culture studies showed that, in the presence of ghrelin and dopamine, GHS-R and D1R form heterodimers, which modified G-protein signal transduction resulting in amplification of dopamine signaling. We speculate that aging is associated with deficient endogenous ghrelin signaling that can be rescued by intervention with GHS-R1a agonists to improve quality of life and maintain independence.

  17. European Counterpublics? DiEM25, Plan B and the Agonistic European Public Sphere

    DEFF Research Database (Denmark)

    Agustin, Oscar Garcia

    2017-01-01

    Plan B in Europe’ (Plan B) and the Democracy in Europe Movement 2025 (DiEM25). These initiatives emerged to promote a new European project as a rejection of EU austerity policies and lack of democracy. The shaping of alternatives is understood within the framework of the public sphere...... and agonistic public sphere from perspectives and experiences which, while sharing the need of internationalization, develop different strategies....

  18. Effects of coumestrol on lipid and glucose metabolism as a farnesoid X receptor ligand

    International Nuclear Information System (INIS)

    Takahashi, Miki; Kanayama, Tomohiko; Yashiro, Takuya; Kondo, Hidehiko; Murase, Takatoshi; Hase, Tadashi; Tokimitsu, Ichiro; Nishikawa, Jun-ichi; Sato, Ryuichiro

    2008-01-01

    In the course of an effort to identify novel agonists of the farnesoid X receptor (FXR), coumestrol was determined to be one such ligand. Reporter and in vitro coactivator interaction assays revealed that coumestrol bound and activated FXR. Treatment of Hep G2 cells with coumestrol stimulated the expression of FXR target genes, thereby regulating the expression of target genes of the liver X receptor and hepatocyte nuclear factor-4α. Through these actions, coumestrol is expected to exert beneficial effects on lipid and glucose metabolism

  19. Dopamine Gene Profiling to Predict Impulse Control and Effects of Dopamine Agonist Ropinirole.

    Science.gov (United States)

    MacDonald, Hayley J; Stinear, Cathy M; Ren, April; Coxon, James P; Kao, Justin; Macdonald, Lorraine; Snow, Barry; Cramer, Steven C; Byblow, Winston D

    2016-07-01

    Dopamine agonists can impair inhibitory control and cause impulse control disorders for those with Parkinson disease (PD), although mechanistically this is not well understood. In this study, we hypothesized that the extent of such drug effects on impulse control is related to specific dopamine gene polymorphisms. This double-blind, placebo-controlled study aimed to examine the effect of single doses of 0.5 and 1.0 mg of the dopamine agonist ropinirole on impulse control in healthy adults of typical age for PD onset. Impulse control was measured by stop signal RT on a response inhibition task and by an index of impulsive decision-making on the Balloon Analogue Risk Task. A dopamine genetic risk score quantified basal dopamine neurotransmission from the influence of five genes: catechol-O-methyltransferase, dopamine transporter, and those encoding receptors D1, D2, and D3. With placebo, impulse control was better for the high versus low genetic risk score groups. Ropinirole modulated impulse control in a manner dependent on genetic risk score. For the lower score group, both doses improved response inhibition (decreased stop signal RT) whereas the lower dose reduced impulsiveness in decision-making. Conversely, the higher score group showed a trend for worsened response inhibition on the lower dose whereas both doses increased impulsiveness in decision-making. The implications of the present findings are that genotyping can be used to predict impulse control and whether it will improve or worsen with the administration of dopamine agonists.

  20. Impulse control disorders in Chinese Parkinson's disease patients: the effect of ergot derived dopamine agonist.

    Science.gov (United States)

    Auyeung, M; Tsoi, T H; Tang, W K; Cheung, C M; Lee, C N; Li, R; Yeung, Eric

    2011-09-01

    We studied the prevalence and related risk factors of impulse control disorders in Chinese Parkinson's disease patients. We screened all non-demented Parkinson's disease patients attending our Parkinson's disease clinic from August 2009 to March 2010. The clinical characteristics of patients with impulse control disorders and those without were compared. Of the 213 PD subjects screened, 15 (7.0%) with impulse control disorders were identified. Fourteen of these subjects were on both a dopamine agonist and Levodopa, and one was on Levodopa alone. Of the fourteen subjects on both a dopamine agonist and Levodopa, eleven were on bromocriptine and Levodopa; 10.5% of the subjects exposed to bromocriptine had impulse control disorder. Upon multivariate analysis, dose of dopamine agonist used, young age at onset of Parkinson's disease and a history of anxiety or depression were independent predictors for developing impulse control disorders. 7% of our Chinese PD subjects had impulse control disorders. When young Parkinson's disease patients with a history of anxiety or depression are treated with high dose of DA, they are at risk of developing impulse control disorders. Copyright © 2011 Elsevier Ltd. All rights reserved.

  1. Effects of the potential 5-HT7 receptor agonist AS 19 in an autoshaping learning task.

    Science.gov (United States)

    Perez-García, Georgina S; Meneses, A

    2005-08-30

    This work aimed to evaluate further the role of 5-HT7 receptors during memory formation in an autoshaping Pavlovian/instrumental learning task. Post-training administration of the potential 5-HT7 receptor agonist AS 19 or antagonist SB-269970 enhanced memory formation or had no effect, respectively. The AS 19 facilitatory effect was reversed by SB-269970, but not by the selective 5-HT1A antagonist WAY100635. Amnesia induced by scopolamine (cholinergic antagonist) or dizocilpine (NMDA antagonist) was also reversed by AS 19. Certainly, reservations regarding the selectivity of AS 19 for 5-HT7 and other 5-HT receptors in vivo are noteworthy and, therefore, its validity for use in animal models as a pharmacological tool. Having mentioned that, it should be noticed that together these data are providing further support to the notion of the 5-HT7 receptors role in memory formation. Importantly, this 5-HT7 receptor agonist AS 19 appears to represent a step forward respect to the notion that potent and selective 5-HT7 receptor agonists can be useful in the treatment of dysfunctional memory in aged-related decline and Alzheimer's disease.

  2. Comparison of long GnRH agonist versus GnRH antagonist protocol in poor responders

    Directory of Open Access Journals (Sweden)

    Sadık Şahin

    2014-12-01

    Full Text Available Objective: To compare long GnRH agonist with GnRH antagonist protocol in poor responders. Materials and Methods: Medical charts of 531 poor responder women undergoing in-vitro fertilization (IVF cycle at Zeynep Kamil Maternity and Children’s Hospital, IVF Center were retrospectively analysed. Those who received at least 300 IU/daily gonadotropin and had ≤3 oocytes retrieved were enrolled in the study. Poor responders were categorized into two groups as those who received long GnRH agonist or GnRH antagonist regimen. Results: Treatment duration and total gonadotropin dosage were significantly higher in women undergoing the long GnRH agonist regimen compared with the GnRH antagonist regimen (p<0.001 for both. Although the number of total and mature oocytes retrieved was similar between the groups, good quality embryos were found to be higher in the GnRH antagonist regimen. The day of embryo transfer and number of transferred embryos were similar in the groups. No statistically significant differences were detected in pregnancy (10.5% vs 14.1%, clinical pregnancy (7.7% vs 10.6% and early pregnancy loss rates (27.2% vs 35% between the groups. Conclusion: GnRH antagonist regimen may be preferable to long GnRH regimen as it could decrease the cost and treatment duration in poor responders.

  3. Changes in heart rate associated with contest outcome in agonistic encounters in lobsters.

    Science.gov (United States)

    Hernáindez-Falcón, Jesús; Basu, Alo C; Govindasamy, Siddhartan; Kravitz, Edward A

    2005-03-01

    Agonistic contests between lobsters housed together in a confined space progress through encounters of increasing intensity until a dominance relationship is established. Once this relationship is established, losing animals continually retreat from the advances of winners. These encounters are likely to consume much energy in both winning and losing animals. Therefore, one might expect involvement of many physiological systems before, during and after fights. Here, we report effects of agonistic encounters on cardiac frequency in winning and losing adult lobsters involved in dyadic interactions. The results show that: (i) small but significant increases in heart rate are observed upon chemical detection of a conspecific; (ii) during agonistic interactions, further increases in heart rate are seen; and (iii) ultimate winners exhibit greater increases in heart rate lasting longer periods of time compared to ultimate losers. Heart rate in winners remains elevated for at least 15 min after the contests have ended and animals have been returned to their home tanks. Reduced effects are seen in second and third pairings between familiar opponents. The sustained changes in heart rate that we observe in winning lobsters may result from hormonal modulation of cardiac function related to the change in social status brought about by contest outcome.

  4. Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity.

    Science.gov (United States)

    Haskell-Luevano, C; Sawyer, T K; Hendrata, S; North, C; Panahinia, L; Stum, M; Staples, D J; Castrucci, A M; Hadley, M F; Hruby, V J

    1996-01-01

    Truncation studies of alpha-melanotropin peptides identify tripeptide analogues exhibiting prolonged agonist bioactivity: PEPTIDES 17(6) 995-1002, 1996.-Systematic analysis of fragment derivatives of the superpotent alpha-MSH analogue. Ac-Ser.Tyr-Ser-Nle4-Glu- His-DPhe7-Arg-Trp-Gly-Lys-Pro-Val-NH2(NDP-MSH), led to the discovery of tripeptide agonists possessing prolonged bioactivity in the frog skin assay. Of particular significance to this discovery was Ac-DPhe-Arg-DTrp-NH2, which was the most potent tripeptide in this series exhibiting sustained melanotropic activity. Different pharmacophore models appear to exist that are dependent on the substructure and stereochemistry of the MSH(6-9) "active site." The tripeptides Ac-DPhe-Arg-Trp-NH2, Ac-DPhe-Arg-DTrp-NH2, and Ac-DPhe-DArg-Trp-NH2 stereo-chemical combinations require only Phe7-Xaa8-Trp9, whereas Ac-DPhe-DArg-DTrp-NH2, Ac-Phe-Arg-DTrp-NH2, and Ac-Phe-Arg-Trp-NH2 additionally require His4 for minimal biological activity. Ac-DPhe-Arg-DTrp-NH2 represents a novel prototype lead for the development of MSH-based peptidomimetic agonists.

  5. A Unified Model of the GABA(A) Receptor Comprising Agonist and Benzodiazepine Binding Sites

    DEFF Research Database (Denmark)

    Kongsbak, Kristine Grønning; Bergmann, Rikke; Sørensen, Pernille Louise

    2013-01-01

    We present a full-length a1b2c2 GABA receptor model optimized for agonists and benzodiazepine (BZD) allosteric modulators. We propose binding hypotheses for the agonists GABA, muscimol and THIP and for the allosteric modulator diazepam (DZP). The receptor model is primarily based on the glutamate......-gated chloride channel (GluCl) from C. elegans and includes additional structural information from the prokaryotic ligand-gated ion channel ELIC in a few regions. Available mutational data of the binding sites are well explained by the model and the proposed ligand binding poses. We suggest a GABA binding mode...... of the agonists in the orthosteric site. The carbonyl group of DZP is predicted to interact with two threonines a1T206 and c2T142, similar to the acidic moiety of GABA. The chlorine atom of DZP is placed near the important a1H101 and the N-methyl group near a1Y159, a1T206, and a1Y209. We present a binding mode...

  6. Nanoparticles containing a liver X receptor agonist inhibit inflammation and atherosclerosis.

    Science.gov (United States)

    Zhang, Xue-Qing; Even-Or, Orli; Xu, Xiaoyang; van Rosmalen, Mariska; Lim, Lucas; Gadde, Suresh; Farokhzad, Omid C; Fisher, Edward A

    2015-01-28

    Liver X receptor (LXR) signaling pathways regulate lipid metabolism and inflammation, which has generated widespread interest in developing synthetic LXR agonists as potential therapeutics for the management of atherosclerosis. In this study, it is demonstrated that nanoparticles (NPs) containing the synthetic LXR agonist GW3965 (NP-LXR) exert anti-inflammatory effects and inhibit the development of atherosclerosis without causing hepatic steatosis. These NPs are engineered through self-assembly of a biodegradable diblock poly(lactide-co-glycolide)-b-poly(ethylene glycol) (PLGA-b-PEG) copolymer. NP-LXR is significantly more effective than free GW3965 at inducing LXR-target gene expression and suppressing inflammatory factors in macrophages in vitro and in vivo. Additionally, the NPs elicit negligible lipogenic gene stimulation in the liver. Using the Ldlr (-/-) mouse model of atherosclerosis, abundant colocalization of fluorescently labeled NPs within plaque macrophages following systemic administration is seen. Notably, six intravenous injections of NP-LXR over 2 weeks markedly reduce the CD68-positive cell (macrophage) content of plaques (by 50%) without increasing total cholesterol or triglycerides in the liver and plasma. Together, these findings identify GW3965-encapsulated PLGA-b-PEG NPs as a promising nanotherapeutic approach to combat atherosclerosis, providing the benefits of LXR agonists without their adverse effects on hepatic and plasma lipid metabolism. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Anticancer Role of PPARγ Agonists in Hematological Malignancies Found in the Vasculature, Marrow, and Eyes

    Directory of Open Access Journals (Sweden)

    P. J. Simpson-Haidaris

    2010-01-01

    Full Text Available The use of targeted cancer therapies in combination with conventional chemotherapeutic agents and/or radiation treatment has increased overall survival of cancer patients. However, longer survival is accompanied by increased incidence of comorbidities due, in part, to drug side effects and toxicities. It is well accepted that inflammation and tumorigenesis are linked. Because peroxisome proliferator-activated receptor (PPAR-γ agonists are potent mediators of anti-inflammatory responses, it was a logical extension to examine the role of PPARγ agonists in the treatment and prevention of cancer. This paper has two objectives: first to highlight the potential uses for PPARγ agonists in anticancer therapy with special emphasis on their role when used as adjuvant or combined therapy in the treatment of hematological malignancies found in the vasculature, marrow, and eyes, and second, to review the potential role PPARγ and/or its ligands may have in modulating cancer-associated angiogenesis and tumor-stromal microenvironment crosstalk in bone marrow.

  8. Beta agonists in livestock feed: status, health concerns, and international trade.

    Science.gov (United States)

    Centner, T J; Alvey, J C; Stelzleni, A M

    2014-09-01

    Since the U.S. Food and Drug Administration approved ractopamine hydrochloride and zilpaterol hydrochloride in animal feeds, usage of those compounds has been a topic of worldwide debate. Ractopamine and zilpaterol are β-adrenergic agonists used as veterinary drugs to increase weight gain in certain animals raised for food. The Joint FAO/WHO Expert Committee on Food Additives (JECFA) established maximum residue limits for ractopamine, which were adopted by the Codex Alimentarius Commission (Codex). No maximum residue limits for zilpaterol have been adopted by JECFA, and new reports of animal mobility issues confront the use of this feed additive. However, many countries disagree with the Codex standards and are restricting or banning meat products containing β agonists. The bans by major importers of U.S. meat products have prompted some to advocate that the United States use the World Trade Organization dispute settlement body. This paper looks at the developments to provide a fuller accounting of what the issues may mean to U.S. firms selling meat products containing residues of β agonists.

  9. Molecular and Therapeutic Characterization of Anti-ectodysplasin A Receptor (EDAR) Agonist Monoclonal Antibodies*

    Science.gov (United States)

    Kowalczyk, Christine; Dunkel, Nathalie; Willen, Laure; Casal, Margret L.; Mauldin, Elizabeth A.; Gaide, Olivier; Tardivel, Aubry; Badic, Giovanna; Etter, Anne-Lise; Favre, Manuel; Jefferson, Douglas M.; Headon, Denis J.; Demotz, Stéphane; Schneider, Pascal

    2011-01-01

    The TNF family ligand ectodysplasin A (EDA) and its receptor EDAR are required for proper development of skin appendages such as hair, teeth, and eccrine sweat glands. Loss of function mutations in the Eda gene cause X-linked hypohidrotic ectodermal dysplasia (XLHED), a condition that can be ameliorated in mice and dogs by timely administration of recombinant EDA. In this study, several agonist anti-EDAR monoclonal antibodies were generated that cross-react with the extracellular domains of human, dog, rat, mouse, and chicken EDAR. Their half-life in adult mice was about 11 days. They induced tail hair and sweat gland formation when administered to newborn EDA-deficient Tabby mice, with an EC50 of 0.1 to 0.7 mg/kg. Divalency was necessary and sufficient for this therapeutic activity. Only some antibodies were also agonists in an in vitro surrogate activity assay based on the activation of the apoptotic Fas pathway. Activity in this assay correlated with small dissociation constants. When administered in utero in mice or at birth in dogs, agonist antibodies reverted several ectodermal dysplasia features, including tooth morphology. These antibodies are therefore predicted to efficiently trigger EDAR signaling in many vertebrate species and will be particularly suited for long term treatments. PMID:21730053

  10. Adenosine A(2A) receptor dynamics studied with the novel fluorescent agonist Alexa488-APEC.

    Science.gov (United States)

    Brand, Frank; Klutz, Athena M; Jacobson, Kenneth A; Fredholm, Bertil B; Schulte, Gunnar

    2008-08-20

    G protein-coupled receptors, such as the adenosine A(2A) receptor, are dynamic proteins, which undergo agonist-dependent redistribution from the cell surface to intracellular membranous compartments, such as endosomes. In order to study the kinetics of adenosine A(2A) receptor redistribution in living cells, we synthesized a novel fluorescent agonist, Alexa488-APEC. Alexa488-APEC binds to adenosine A(2A) (K(i)=149+/-27 nM) as well as A(3) receptors (K(i)=240+/-160 nM) but not to adenosine A(1) receptors. Further, we characterized the dose-dependent increase in Alexa488-APEC-induced cAMP production as well as cAMP response element binding (CREB) protein phosphorylation, verifying the ligand's functionality at adenosine A(2A) but not A(2B) receptors. In live-cell imaging studies, Alexa488-APEC-induced adenosine A(2A) receptor internalization, which was blocked by the competitive reversible antagonist ZM 241385 and hyperosmolaric sucrose. Further, internalized adenosine A(2A) receptors co-localized with clathrin and Rab5, indicating that agonist stimulation promotes adenosine A(2A) receptor uptake through a clathrin-dependent mechanism to Rab5-positive endosomes. The basic characterization of Alexa488-APEC described here showed that it provides a useful tool for tracing adenosine A(2A) receptors in vitro.

  11. Identification of Natural Compound Carnosol as a Novel TRPA1 Receptor Agonist

    Directory of Open Access Journals (Sweden)

    Chenxi Zhai

    2014-11-01

    Full Text Available The transient receptor potential ankyrin 1 (TRPA1 cation channel is one of the well-known targets for pain therapy. Herbal medicine is a rich source for new drugs and potentially useful therapeutic agents. To discover novel natural TRPA1 agonists, compounds isolated from Chinese herbs were screened using a cell-based calcium mobilization assay. Out of the 158 natural compounds derived from traditional Chinese herbal medicines, carnosol was identified as a novel agonist of TRPA1 with an EC50 value of 12.46 µM. And the agonistic effect of carnosol on TRPA1 could be blocked by A-967079, a selective TRPA1 antagonist. Furthermore, the specificity of carnosol was verified as it showed no significant effects on two other typical targets of TRP family member: TRPM8 and TRPV3. Carnosol exhibited anti-inflammatory and anti-nociceptive properties; the activation of TRPA1 might be responsible for the modulation of inflammatory nociceptive transmission. Collectively, our findings indicate that carnosol is a new anti-nociceptive agent targeting TRPA1 that can be used to explore further biological role in pain therapy.

  12. Design and synthesis of small molecule agonists of EphA2 receptor.

    Science.gov (United States)

    Petty, Aaron; Idippily, Nethrie; Bobba, Viharika; Geldenhuys, Werner J; Zhong, Bo; Su, Bin; Wang, Bingcheng

    2018-01-01

    Ligand-independent activation of EphA2 receptor kinase promotes cancer metastasis and invasion. Activating EphA2 receptor tyrosine kinase with small molecule agonist is a novel strategy to treat EphA2 overexpressing cancer. In this study, we performed a lead optimization of a small molecule Doxazosin that was identified as an EphA2 receptor agonist. 33 new analogs were developed and evaluated; a structure-activity relationship was summarized based on the EphA2 activation of these derivatives. Two new derivative compounds 24 and 27 showed much improved activity compared to Doxazosin. Compound 24 possesses a bulky amide moiety, and compound 27 has a dimeric structure that is very different to the parental compound. Compound 27 with a twelve-carbon linker of the dimer activated the kinase and induced receptor internalization and cell death with the best potency. Another dimer with a six-carbon linker has significantly reduced potency compared to the dimer with a longer linker, suggesting that the length of the linker is critical for the activity of the dimeric agonist. To explore the receptor binding characteristics of the new molecules, we applied a docking study to examine how the small molecule binds to the EphA2 receptor. The results reveal that compounds 24 and 27 form more hydrogen bonds to EphA2 than Doxazosin, suggesting that they may have higher binding affinity to the receptor. Published by Elsevier Masson SAS.

  13. LXR agonist rescued the deficit in the proliferation of the cerebellar granule cells induced by dexamethasone

    Energy Technology Data Exchange (ETDEWEB)

    Bian, Xuting; Zhong, Hongyu; Li, Fen; Cai, Yulong; Li, Xin; Wang, Lian; Fan, Xiaotang, E-mail: fanxiaotang2005@163.com

    2016-09-02

    Dexamethasone (DEX) exposure during early postnatal life produces permanent neuromotor and intellectual deficits and stunts cerebellar growth. The liver X receptor (LXR) plays important roles in CNS development. However, the effects of LXR on the DEX-mediated impairment of cerebellar development remain undetermined. Thus, mice were pretreated with LXR agonist TO901317 (TO) and were later exposed to DEX to evaluate its protective effects on DEX-mediated deficit during cerebellar development. The results showed that an acute exposure of DEX on postnatal day 7 resulted in a significant impairment in cerebellar development and decreased the proliferation of granule neuron precursors in the external granule layer of cerebellum. This effect was attenuated by pretreatment with TO. We further found that the decrease in the proliferation caused by DEX occurred via up-regulation of glucocorticoid receptor and p27kip1, which could be partially prevented by LXR agonist pretreatment. Overall, our results suggest that LXR agonist pretreatment could protect against DEX-induced deficits in cerebellar development in postnatal mice and may thus be perspective recruited to counteract such GC side effects.

  14. Melanocortin Receptor Agonists Facilitate Oxytocin-Dependent Partner Preference Formation in the Prairie Vole.

    Science.gov (United States)

    Modi, Meera E; Inoue, Kiyoshi; Barrett, Catherine E; Kittelberger, Kara A; Smith, Daniel G; Landgraf, Rainer; Young, Larry J

    2015-07-01

    The central melanocortin (MC) system has been widely studied for its effects on food intake and sexual behavior. However, the MC system, and more specifically the MC4 receptor (MC4R), also interacts with neurochemical systems that regulate socioemotional behaviors, including oxytocin (OT) and dopamine. In monogamous prairie voles, OT and dopamine interact to promote partner preference formation, a laboratory measure of an enduring social bond between mates. Here we investigated the effects of MC receptor activation on partner preference formation in prairie voles, as well as the interaction between the MC and OT systems during this process. Peripheral administration of the brain penetrant MC3/4R receptor peptide agonist, Melanotan II (MTII), and the highly selective, small-molecule MC4R agonist, Pf-446687, enhanced partner preference formation in the prairie vole, but not in the non-monogamous meadow vole. MTII-induced partner preferences were enduring, as they were present 1 week after drug manipulation. The prosocial effects of MCR agonists may be mediated, in part, through modulation of OT, as coadministration of an OT receptor antagonist prevented MTII-induced partner preferences. MTII also selectively activated hypothalamic OT neurons and potentiated central OT release. As OT has been shown to enhance some aspects of social cognition in humans, our data suggest that the MC4R may be a viable therapeutic target for enhancing social function in psychiatric disorders, including autism spectrum disorders and schizophrenia, potentially through activation of the OT system.

  15. CTDP-32476: A Promising Agonist Therapy for Treatment of Cocaine Addiction

    Science.gov (United States)

    Xi, Zheng-Xiong; Song, Rui; Li, Xia; Lu, Guan-Yi; Peng, Xiao-Qing; He, Yi; Bi, Guo-Hua; Sheng, Siyuan Peter; Yang, Hong-Ju; Zhang, Haiying; Li, Jin; Froimowitz, Mark; Gardner, Eliot L

    2017-01-01

    Agonist-replacement therapies have been successfully used for treatment of opiate and nicotine addiction, but not for cocaine addiction. One of the major obstacles is the cocaine-like addictive potential of the agonists themselves. We report here an atypical dopamine (DA) transporter (DAT) inhibitor, CTDP-32476, that may have translational potential for treating cocaine addiction. In vitro ligand-binding assays suggest that CTDP-32476 is a potent and selective DAT inhibitor and a competitive inhibitor of cocaine binding to the DAT. Systemic administration of CTDP-32476 alone produced a slow-onset, long-lasting increase in extracellular nucleus accumbens DA, locomotion, and brain-stimulation reward. Drug-naive rats did not self-administer CTDP-32476. In a substitution test, cocaine self-administration rats displayed a progressive reduction in CTDP-32476 self-administration with an extinction pattern of drug-taking behavior, suggesting significantly lower addictive potential than cocaine. Pretreatment with CTDP-32476 inhibited cocaine self-administration, cocaine-associated cue-induced relapse to drug seeking, and cocaine-enhanced extracellular DA in the nucleus accumbens. These findings suggest that CTDP-32476 is a unique DAT inhibitor that not only could satisfy ‘drug hunger' through its slow-onset long-lasting DAT inhibitor action, but also render subsequent administration of cocaine ineffectual—thus constituting a novel and unique compound with translational potential as an agonist therapy for treatment of cocaine addiction. PMID:27534265

  16. Quantum chemical study of agonist-receptor vibrational interactions for activation of the glutamate receptor.

    Science.gov (United States)

    Kubo, M; Odai, K; Sugimoto, T; Ito, E

    2001-06-01

    To understand the mechanism of activation of a receptor by its agonist, the excitation and relaxation processes of the vibrational states of the receptor should be examined. As a first approach to this problem, we calculated the normal vibrational modes of agonists (glutamate and kainate) and an antagonist (6-cyano-7-nitroquinoxaline-2,3-dione: CNQX) of the glutamate receptor, and then investigated the vibrational interactions between kainate and the binding site of glutamate receptor subunit GluR2 by use of a semiempirical molecular orbital method (MOPAC2000-PM3). We found that two local vibrational modes of kainate, which were also observed in glutamate but not in CNQX, interacted through hydrogen bonds with the vibrational modes of GluR2: (i) the bending vibration of the amine group of kainate, interacting with the stretching vibration of the carboxyl group of Glu705 of GluR2, and (ii) the symmetric stretching vibration of the carboxyl group of kainate, interacting with the bending vibration of the guanidinium group of Arg485. We also found collective modes with low frequency at the binding site of GluR2 in the kainate-bound state. The vibrational energy supplied by an agonist may flow from the high-frequency local modes to the low-frequency collective modes in a receptor, resulting in receptor activation.

  17. A Novel Role of Serotonin Receptor 2B Agonist as an Anti-Melanogenesis Agent

    Directory of Open Access Journals (Sweden)

    Eun Ju Oh

    2016-04-01

    Full Text Available BW723C86, a serotonin receptor 2B agonist, has been investigated as a potential therapeutic for various conditions such as anxiety, hyperphagia and hypertension. However, the functional role of BW723C86 against melanogenesis remains unclear. In this study, we investigate the effect of serotonin receptor 2B (5-HTR2B agonist on melanogenesis and elucidate the mechanism involved. BW723C86 reduced melanin synthesis and intracellular tyrosinase activity in melan-A cells and normal human melanocytes. The expression of melanogenesis-related proteins (tyrosinase, TRP-1 and TRP-2 and microphthalmia-associated transcription factor (MITF in melan-A cells decreased after BW723C86 treatment. The promoter activity of MITF was also reduced by BW723C86 treatment. The reduced level of MITF was associated with inhibition of protein kinase A (PKA and cAMP response element-binding protein (CREB activation by BW723C86 treatment. These results suggest that the serotonin agonist BW723C86 could be a potential therapeutic agent for skin hyperpigmentation disorders.

  18. The PPAR alpha agonist gemfibrozil is an ineffective treatment for spinal cord injured mice.

    Science.gov (United States)

    Almad, Akshata; Lash, A Todd; Wei, Ping; Lovett-Racke, Amy E; McTigue, Dana M

    2011-12-01

    Peroxisome Proliferator Activated Receptor (PPAR)-α is a key regulator of lipid metabolism and recent studies reveal it also regulates inflammation in several different disease models. Gemfibrozil, an agonist of PPAR-α, is a FDA approved drug for hyperlipidemia and has been shown to inhibit clinical signs in a rodent model of multiple sclerosis. Since many studies have shown improved outcome from spinal cord injury (SCI) by anti-inflammatory and neuroprotective agents, we tested the efficacy of oral gemfibrozil given before or after SCI for promoting tissue preservation and behavioral recovery after spinal contusion injury in mice. Unfortunately, the results were contrary to our hypothesis; in our first attempt, gemfibrozil treatment exacerbated locomotor deficits and increased tissue pathology after SCI. In subsequent experiments, the behavioral effects were not replicated but histological outcomes again were worse. We also tested the efficacy of a different PPAR-α agonist, fenofibrate, which also modulates immune responses and is beneficial in several neurodegenerative disease models. Fenofibrate treatment did not improve recovery, although there was a slight trend for a modest increase in histological tissue sparing. Based on our results, we conclude that PPAR-α agonists yield either no effect or worsen recovery from spinal cord injury, at least at the doses and the time points of drug delivery tested here. Further, patients sustaining spinal cord injury while taking gemfibrozil might be prone to exacerbated tissue damage. Copyright © 2011 Elsevier Inc. All rights reserved.

  19. LXR agonist rescued the deficit in the proliferation of the cerebellar granule cells induced by dexamethasone

    International Nuclear Information System (INIS)

    Bian, Xuting; Zhong, Hongyu; Li, Fen; Cai, Yulong; Li, Xin; Wang, Lian; Fan, Xiaotang

    2016-01-01

    Dexamethasone (DEX) exposure during early postnatal life produces permanent neuromotor and intellectual deficits and stunts cerebellar growth. The liver X receptor (LXR) plays important roles in CNS development. However, the effects of LXR on the DEX-mediated impairment of cerebellar development remain undetermined. Thus, mice were pretreated with LXR agonist TO901317 (TO) and were later exposed to DEX to evaluate its protective effects on DEX-mediated deficit during cerebellar development. The results showed that an acute exposure of DEX on postnatal day 7 resulted in a significant impairment in cerebellar development and decreased the proliferation of granule neuron precursors in the external granule layer of cerebellum. This effect was attenuated by pretreatment with TO. We further found that the decrease in the proliferation caused by DEX occurred via up-regulation of glucocorticoid receptor and p27kip1, which could be partially prevented by LXR agonist pretreatment. Overall, our results suggest that LXR agonist pretreatment could protect against DEX-induced deficits in cerebellar development in postnatal mice and may thus be perspective recruited to counteract such GC side effects.

  20. Beta-Adrenergic Receptors and Mechanisms in Asthma: The New Long-Acting Beta-Agonists

    Directory of Open Access Journals (Sweden)

    Robert G Townley

    1996-01-01

    Full Text Available The objective is to review β-adrenergic receptors and mechanisms in the immediate and late bronchial reaction in asthma and the new long-acting β-agonist. This will be discussed in light of the controversy of the potential adverse effect of regular use of long-acting β-agonists. We studied the effect of formoterol on the late asthmatic response (LAR and airway inflammation in guinea-pigs. Formoterol suppressed the LAR, antigen-induced airway inflammation and hyperresponsiveness, although isoproterenol failed to inhibit these parameters. β-Adrenergic hyporesponsiveness, and cholinergic and a- adrenergic hyperresponsiveness have been implicated in the pathogenesis of asthma. A decrease in β-adrenoreceptor function can result either from exogenously administered β-agonist or from exposure to allergens resulting in a late bronchial reaction. There is increasing evidence that eosinophils, macrophages, and lymphocytes which are of primary importance in the late bronchial reaction are also modulated by β2- adrenoreceptors. In functional studies of guinea-pig or human isolated trachea and lung parenchyma, PAF and certain cytokines significantly reduced the potency of isoproterenol to reverse methacholine- or histamine-induced contraction. The effect of glucocorticoids on pulmonary β-adrenergic receptors and responses suggests an important role for glucocorticoids to increase β-adrenergic receptors and responsiveness.

  1. Agonist and antagonist binding to rat brain muscarinic receptors: influence of aging

    International Nuclear Information System (INIS)

    Gurwitz, D.; Egozi, Y.; Henis, Y.I.; Kloog, Y.; Sokolovsky, M.

    1987-01-01

    The objective of the present study was to determine the binding properties of muscarinic receptors in six brain regions in mature and old rats of both sexes by employing direct binding of [ 3 H]-antagonist as well as of the labeled natural neurotransmitter, [ 3 H]-acetylcholine [( 3 H]-AcCh). In addition, age-related factors were evaluated in the modulation processes involved in agonist binding. The results indicate that as the rat ages the density of the muscarinic receptors is altered differently in the various brain regions: it is decreased in the cerebral cortex, hippocampus, striatum and olfactory bulb of both male and female rats, but is increased (58%) in the brain stem of senescent males while no significant change is observed for females. The use of the highly sensitive technique measuring direct binding of [ 3 H]-AcCh facilitated the separate detection of age-related changes in the two classes (high- and low-affinity) of muscarinic agonist binding sites. In old female rats the density of high-affinity [ 3 H]-AcCh binding sites was preserved in all tissues studied, indicating that the decreases in muscarinic receptor density observed with [ 3 H]-antagonist represent a loss of low-affinity agonist binding sites. In contrast, [ 3 H]-AcCh binding is decreased in the hypothalamus and increased in the brain stem of old male rats. These data imply sexual dimorphism of the aging process in central cholinergic mechanisms

  2. A Rationally Designed Agonist Defines Subfamily IIIA Abscisic Acid Receptors As Critical Targets for Manipulating Transpiration.

    Science.gov (United States)

    Vaidya, Aditya S; Peterson, Francis C; Yarmolinsky, Dmitry; Merilo, Ebe; Verstraeten, Inge; Park, Sang-Youl; Elzinga, Dezi; Kaundal, Amita; Helander, Jonathan; Lozano-Juste, Jorge; Otani, Masato; Wu, Kevin; Jensen, Davin R; Kollist, Hannes; Volkman, Brian F; Cutler, Sean R

    2017-11-17

    Increasing drought and diminishing freshwater supplies have stimulated interest in developing small molecules that can be used to control transpiration. Receptors for the plant hormone abscisic acid (ABA) have emerged as key targets for this application, because ABA controls the apertures of stomata, which in turn regulate transpiration. Here, we describe the rational design of cyanabactin, an ABA receptor agonist that preferentially activates Pyrabactin Resistance 1 (PYR1) with low nanomolar potency. A 1.63 Å X-ray crystallographic structure of cyanabactin in complex with PYR1 illustrates that cyanabactin's arylnitrile mimics ABA's cyclohexenone oxygen and engages the tryptophan lock, a key component required to stabilize activated receptors. Further, its sulfonamide and 4-methylbenzyl substructures mimic ABA's carboxylate and C6 methyl groups, respectively. Isothermal titration calorimetry measurements show that cyanabactin's compact structure provides ready access to high ligand efficiency on a relatively simple scaffold. Cyanabactin treatments reduce Arabidopsis whole-plant stomatal conductance and activate multiple ABA responses, demonstrating that its in vitro potency translates to ABA-like activity in vivo. Genetic analyses show that the effects of cyanabactin, and the previously identified agonist quinabactin, can be abolished by the genetic removal of PYR1 and PYL1, which form subclade A within the dimeric subfamily III receptors. Thus, cyanabactin is a potent and selective agonist with a wide spectrum of ABA-like activities that defines subfamily IIIA receptors as key target sites for manipulating transpiration.

  3. Chronic β2 -adrenoceptor agonist treatment alters muscle proteome and functional adaptations induced by high intensity training in young men

    DEFF Research Database (Denmark)

    Hostrup, Morten; Onslev, Johan; Jacobson, Glenn

    2018-01-01

    Although the effects of training have been studied for decades, data on muscle proteome signature remodelling induced by high intensity training in relation to functional changes in humans remains incomplete. Likewise, β2 -agonists are frequently used to counteract exercise......-induced bronchoconstriction, but the effects β2 -agonist treatment on muscle remodelling and adaptations to training are unknown. In a placebo-controlled parallel study, we randomized 21 trained men to four weeks of high intensity training with (HIT + β2 A) or without (HIT) daily inhalation of β2 -agonist (terbutaline, 4 mg...... (P ≤ 0.01) and exercise performance (11.6 vs. 6.1%, P ≤ 0.05) in HIT + β2 A compared to HIT. These findings indicate that daily β2 -agonist treatment attenuates the beneficial effects of high intensity training on exercise performance and oxidative capacity, and causes remodelling of muscle proteome...

  4. Discovery of N-(4-aryl-5-aryloxy-thiazol-2-yl)-amides as potent RORγt inverse agonists.

    Science.gov (United States)

    Wang, Yonghui; Yang, Ting; Liu, Qian; Ma, Yingli; Yang, Liuqing; Zhou, Ling; Xiang, Zhijun; Cheng, Ziqiang; Lu, Sijie; Orband-Miller, Lisa A; Zhang, Wei; Wu, Qianqian; Zhang, Kathleen; Li, Yi; Xiang, Jia-Ning; Elliott, John D; Leung, Stewart; Ren, Feng; Lin, Xichen

    2015-09-01

    A novel series of N-(4-aryl-5-aryloxy-thiazol-2-yl)-amides as RORγt inverse agonists was discovered. Binding mode analysis of a RORγt partial agonist (2c) revealed by co-crystal structure in RORγt LBD suggests that the inverse agonists do not directly interfere with the interaction between H12 and the RORγt LBD. Detailed SAR exploration led to identification of potent RORγt inverse agonists such as 3m with a pIC50 of 8.0. Selected compounds in the series showed reasonable activity in Th17 cell differentiation assay as well as low intrinsic clearance in mouse liver microsomes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Agonist-induced internalisation of the glucagon-like peptide-1 receptor is mediated by the Gαq pathway.

    Science.gov (United States)

    Thompson, Aiysha; Kanamarlapudi, Venkateswarlu

    2015-01-01

    The glucagon-like peptide-1 receptor (GLP-1R) is a G-protein-coupled receptor (GPCR) and an important target in the treatment of type 2 diabetes mellitus (T2DM). Upon stimulation with agonist, the GLP-1R signals through both Gαs and Gαq coupled pathways to stimulate insulin secretion. The agonist-induced GLP-1R internalisation has recently been shown to be important for insulin secretion. However, the molecular mechanisms underlying GLP-1R internalisation remain unknown. The aim of this study was to determine the role of GLP-1R downstream signalling pathways in its internalisation. Agonist-induced human GLP-1R (hGLP-1R) internalisation and activity were examined using a number of techniques including immunoblotting, ELISA, immunofluorescence and luciferase assays to determine cAMP production, intracellular Ca(2+) accumulation and ERK phosphorylation. Agonist-induced hGLP-1R internalisation is dependent on caveolin-1 and dynamin. Inhibition of the Gαq pathway but not the Gαs pathway affected hGLP-1R internalisation. Consistent with this, hGLP-1R mutant T149M and small-molecule agonists (compound 2 and compound B), which activate only the Gαs pathway, failed to induce internalisation of the receptor. Chemical inhibitors of the Gαq pathway, PKC and ERK phosphorylation significantly reduced agonist-induced hGLP-1R internalisation. These inhibitors also suppressed agonist-induced ERK1/2 phosphorylation demonstrating that the phosphorylated ERK acts downstream of the Gαq pathway in the hGLP-1R internalisation. In summary, agonist-induced hGLP-1R internalisation is mediated by the Gαq pathway. The internalised hGLP-1R stimulates insulin secretion from pancreatic β-cells, indicating the importance of GLP-1 internalisation for insulin secretion. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. The adenosine A2A receptor agonist CGS 21680 exhibits antipsychotic-like activity in Cebus apella monkeys

    DEFF Research Database (Denmark)

    Andersen, M B; Fuxe, K; Werge, T

    2002-01-01

    The adenosine A2A receptor agonist CGS 21680 has shown effects similar to dopamine antagonists in behavioural assays in rats predictive for antipsychotic activity, without induction of extrapyramidal side-effects (EPS). In the present study, we examined whether this functional dopamine antagonism...... showed a functional anti-dopaminergic effect in Cebus apella monkeys without production of EPS. This further substantiates that adenosine A2A receptor agonists may have potential as antipsychotics with atypical profiles....

  7. Translation of Novel Serotonin 5-HT7 Agonist Drug Candidates in Rodent Models of Fragile X Syndrome

    Science.gov (United States)

    2016-09-01

    HT1A partial agonist for autism . 6th Cisbio HTRF symposium (Brewster, MA), September 14-17, 2015. Acknowledged DOD funding. Teaching Lectures . 10...grant is to synthesize 5-PAT-type 5HT7 receptor agonists and assess their effectiveness to correct FXS phenotypes in Fmr1-KO mice and other mouse models...President of DELSIA (Delivering Science Innovation for Autism ) and Vice President, Innovative Technologies at Autism Speaks, Daniel Smith, who

  8. Interaction between corticosteroid and beta-agonist drugs. Biochemical and cardiovascular effects in normal subjects.

    Science.gov (United States)

    Taylor, D R; Wilkins, G T; Herbison, G P; Flannery, E M

    1992-08-01

    The aim of this study was to investigate whether the administration of prednisone potentiates any of the acute biochemical and cardiovascular effects of high-dose inhaled beta-agonist drugs. These agents are known to cause dose-related changes in plasma potassium and glucose, as well as ECG changes in heart rate, corrected QT interval (QTc), T wave, and U wave. On theoretical grounds, the concomitant use of systemic corticosteroids might enhance these actions. Twenty-four healthy subjects were randomized to receive one of three treatments: salbutamol 5 mg or fenoterol 5 mg or normal saline solution. Each drug was administered twice, 30 min apart by nebulizer, and the procedure was repeated after each subject had received prednisone 30 mg daily for one week. Plasma potassium and glucose levels were measured, and ECGs were obtained after each treatment, together with 12-h Holter monitoring for arrhythmias. Changes in plasma potassium and glucose following nebulized beta-agonist were significantly greater after treatment with prednisone. Baseline potassium level fell from 3.75 mmol/L (95 percent CI 3.61, 3.89) to 3.50 mmol/L (95 percent CI 3.36, 3.64), and thereafter all values were significantly lower at each time point (p = 0.003). The lowest mean plasma potassium was obtained 90 min after fenoterol administration with prednisone pretreatment: 2.78 mmol/L (95 percent CI 2.44, 3.13). Increases in heart rate and QTc interval following both beta-agonist drugs were significant, but T-wave amplitude reductions did not reach significance. Prednisone treatment did not significantly alter the cardiovascular responses. Supraventricular and ventricular ectopic activity was related to beta-agonist use, but no potentiating effect was noted following steroid treatment. We conclude that the acute biochemical effects of beta-agonist administration are augmented by prior treatment with prednisone, but this is not the case for ECG effects. However, the degree of hypokalemia noted as

  9. FXR induces the UGT2B4 enzyme in hepatocytes : A potential mechanism of negative feedback control of FXR activity

    NARCIS (Netherlands)

    Barbier, O; Pineda Torra, I.; Sirvent, A; Claudel, T; Blanquart, C; Duran-Sandoval, D; Kuipers, F; Kosykh, V.; Fruchart, JC; Staels, B

    Background & Aims: Bile acids are essential for bile formation and Intestinal absorption of lipids and fat-soluble vitamins. However, the intrinsic toxicity of hydrophobic bile acids demands a tight control of their intracellular concentrations. Bile acids are ligands for the farnesoid X receptor

  10. PPARγ partial agonist GQ-16 strongly represses a subset of genes in 3T3-L1 adipocytes

    Energy Technology Data Exchange (ETDEWEB)

    Milton, Flora Aparecida [Faculdade de Ciências da Saúde, Laboratório de Farmacologia Molecular, Universidade de Brasília (Brazil); Genomic Medicine, Houston Methodist Research Institute, Houston, TX (United States); Cvoro, Aleksandra [Genomic Medicine, Houston Methodist Research Institute, Houston, TX (United States); Amato, Angelica A. [Faculdade de Ciências da Saúde, Laboratório de Farmacologia Molecular, Universidade de Brasília (Brazil); Sieglaff, Douglas H.; Filgueira, Carly S.; Arumanayagam, Anithachristy Sigamani [Genomic Medicine, Houston Methodist Research Institute, Houston, TX (United States); Caro Alves de Lima, Maria do; Rocha Pitta, Ivan [Laboratório de Planejamento e Síntese de Fármacos – LPSF, Universidade Federal de Pernambuco (Brazil); Assis Rocha Neves, Francisco de [Faculdade de Ciências da Saúde, Laboratório de Farmacologia Molecular, Universidade de Brasília (Brazil); Webb, Paul, E-mail: pwebb@HoustonMethodist.org [Genomic Medicine, Houston Methodist Research Institute, Houston, TX (United States)

    2015-08-28

    Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor gamma (PPARγ) agonists that improve insulin resistance but trigger side effects such as weight gain, edema, congestive heart failure and bone loss. GQ-16 is a PPARγ partial agonist that improves glucose tolerance and insulin sensitivity in mouse models of obesity and diabetes without inducing weight gain or edema. It is not clear whether GQ-16 acts as a partial agonist at all PPARγ target genes, or whether it displays gene-selective actions. To determine how GQ-16 influences PPARγ activity on a gene by gene basis, we compared effects of rosiglitazone (Rosi) and GQ-16 in mature 3T3-L1 adipocytes using microarray and qRT-PCR. Rosi changed expression of 1156 genes in 3T3-L1, but GQ-16 only changed 89 genes. GQ-16 generally showed weak effects upon Rosi induced genes, consistent with partial agonist actions, but a subset of modestly Rosi induced and strongly repressed genes displayed disproportionately strong GQ-16 responses. PPARγ partial agonists MLR24 and SR1664 also exhibit disproportionately strong effects on transcriptional repression. We conclude that GQ-16 displays a continuum of weak partial agonist effects but efficiently represses some negatively regulated PPARγ responsive genes. Strong repressive effects could contribute to physiologic actions of GQ-16. - Highlights: • GQ-16 is an insulin sensitizing PPARγ ligand with reduced harmful side effects. • GQ-16 displays a continuum of weak partial agonist activities at PPARγ-induced genes. • GQ-16 exerts strong repressive effects at a subset of genes. • These inhibitor actions should be evaluated in models of adipose tissue inflammation.

  11. PPARγ partial agonist GQ-16 strongly represses a subset of genes in 3T3-L1 adipocytes

    International Nuclear Information System (INIS)

    Milton, Flora Aparecida; Cvoro, Aleksandra; Amato, Angelica A.; Sieglaff, Douglas H.; Filgueira, Carly S.; Arumanayagam, Anithachristy Sigamani; Caro Alves de Lima, Maria do; Rocha Pitta, Ivan; Assis Rocha Neves, Francisco de; Webb, Paul

    2015-01-01

    Thiazolidinediones (TZDs) are peroxisome proliferator-activated receptor gamma (PPARγ) agonists that improve insulin resistance but trigger side effects such as weight gain, edema, congestive heart failure and bone loss. GQ-16 is a PPARγ partial agonist that improves glucose tolerance and insulin sensitivity in mouse models of obesity and diabetes without inducing weight gain or edema. It is not clear whether GQ-16 acts as a partial agonist at all PPARγ target genes, or whether it displays gene-selective actions. To determine how GQ-16 influences PPARγ activity on a gene by gene basis, we compared effects of rosiglitazone (Rosi) and GQ-16 in mature 3T3-L1 adipocytes using microarray and qRT-PCR. Rosi changed expression of 1156 genes in 3T3-L1, but GQ-16 only changed 89 genes. GQ-16 generally showed weak effects upon Rosi induced genes, consistent with partial agonist actions, but a subset of modestly Rosi induced and strongly repressed genes displayed disproportionately strong GQ-16 responses. PPARγ partial agonists MLR24 and SR1664 also exhibit disproportionately strong effects on transcriptional repression. We conclude that GQ-16 displays a continuum of weak partial agonist effects but efficiently represses some negatively regulated PPARγ responsive genes. Strong repressive effects could contribute to physiologic actions of GQ-16. - Highlights: • GQ-16 is an insulin sensitizing PPARγ ligand with reduced harmful side effects. • GQ-16 displays a continuum of weak partial agonist activities at PPARγ-induced genes. • GQ-16 exerts strong repressive effects at a subset of genes. • These inhibitor actions should be evaluated in models of adipose tissue inflammation

  12. Correlating gene expression with deformities caused by aryl hydrocarbon receptor agonists in zebrafish (Danio rerio)

    Energy Technology Data Exchange (ETDEWEB)

    Bugiak, B.; Weber, L. [Saskatchewan Univ., Saskatoon, SK (Canada)

    2009-07-01

    Exposure to aryl hydrocarbon receptor (AhR) agonists in fish causes lethal disturbances in fish development, but the effects of acute AhR agonist exposure on the cardiovascular system and deformities remain unclear. This study addressed this issue by performing a series of experiments on zebrafish (Danio rerio). The authors hypothesized that genes needed for cardiovascular regulation (PTGS) would exhibit a stronger link to deformities than detoxification enzymes (CYPs). Zebrafish eggs were exposed aqueously until 4 days post-fertilization (dpf) to the AhR agonists benzo(a)pyrene (BaP) or 2,3,7,8-tetrachlorodibenzop-dioxin (TCDD) alone and in combination with the putative AhR antagonists resveratrol or alpha-naphthoflavone (ANF). Gene expression was measured using real-time, reverse transcriptase PCR in zebrafish at 5 and 10 dpf. Although the mortalities did not differ considerably among groups at 10 dpf, the deformities increased significantly after BaP-ANF at 5 dpf and after BaP at 10 dpf, but not after TCDD treatment. CYP and PTGS isozymes exhibited small, but statistically significant changes at 5 dpf. By 10 dpf, the expression returned to control values. In general, CYP1A and PTGS-1 expression at 5 dpf were positively correlated with deformities, while all other genes were negatively correlated with deformities. It was concluded that changes in CYP1A, CYP1C2, and PTGS-1 gene expression at 5 dpf are associated with developmental deformities, but additional work is needed to determine which has the most important mechanistic link.

  13. Alpha-2A Adrenoceptor Agonist Guanfacine Restores Diuretic Efficiency in Experimental Cirrhotic Ascites: Comparison with Clonidine.

    Directory of Open Access Journals (Sweden)

    Giovanni Sansoè

    Full Text Available In human cirrhosis, adrenergic hyperfunction causes proximal tubular fluid retention and contributes to diuretic-resistant ascites, and clonidine, a sympatholytic drug, improves natriuresis in difficult-to-treat ascites.To compare clonidine (aspecific α2-adrenoceptor agonist to SSP-002021R (prodrug of guanfacine, specific α2A-receptor agonist, both associated with diuretics, in experimental cirrhotic ascites.Six groups of 12 rats were studied: controls (G1; controls receiving furosemide and potassium canrenoate (G2; rats with ascitic cirrhosis due to 14-week CCl4 treatment (G3; cirrhotic rats treated (over the 11th-14th CCl4 weeks with furosemide and canrenoate (G4, furosemide, canrenoate and clonidine (G5, or diuretics and SSP002021R (G6. Three rats of each group had their hormonal status and renal function assessed at the end of 11th, 12th, 13th, and 14th weeks of respective treatments.Cirrhotic rats in G3 and G4 gained weight over the 12th-14th CCl4 weeks. In G4, brief increase in sodium excretion over the 11th-12th weeks preceded worsening of inulin clearance and natriuresis (diuretic resistance. In comparison with G4, the addition of clonidine (G5 or guanfacine (G6 to diuretics improved, respectively, sodium excretion over the 11th-12th CCl4 weeks, or GFR and electrolytes excretion over the 13th-14th CCl4 weeks. Natriuretic responses in G5 and G6 were accompanied by reduced catecholamine serum levels.α2A-receptor agonists restore glomerular filtration rate and natriuresis, and delay diuretic-resistant ascites in experimental advanced cirrhosis. Clonidine ameliorates diuretic-dependent natriuresis just for a short time.

  14. Sigma-1 receptor agonists directly inhibit Nav1.2/1.4 channels.

    Directory of Open Access Journals (Sweden)

    Xiao-Fei Gao

    Full Text Available (+-SKF 10047 (N-allyl-normetazocine is a prototypic and specific sigma-1 receptor agonist that has been used extensively to study the function of sigma-1 receptors. (+-SKF 10047 inhibits K(+, Na(+ and Ca2+ channels via sigma-1 receptor activation. We found that (+-SKF 10047 inhibited Na(V1.2 and Na(V1.4 channels independently of sigma-1 receptor activation. (+-SKF 10047 equally inhibited Na(V1.2/1.4 channel currents in HEK293T cells with abundant sigma-1 receptor expression and in COS-7 cells, which barely express sigma-1 receptors. The sigma-1 receptor antagonists BD 1063,BD 1047 and NE-100 did not block the inhibitory effects of (+-SKF-10047. Blocking of the PKA, PKC and G-protein pathways did not affect (+-SKF 10047 inhibition of Na(V1.2 channel currents. The sigma-1 receptor agonists Dextromethorphan (DM and 1,3-di-o-tolyl-guanidine (DTG also inhibited Na(V1.2 currents through a sigma-1 receptor-independent pathway. The (+-SKF 10047 inhibition of Na(V1.2 currents was use- and frequency-dependent. Point mutations demonstrated the importance of Phe(1764 and Tyr(1771 in the IV-segment 6 domain of the Na(V1.2 channel and Phe(1579 in the Na(V1.4 channel for (+-SKF 10047 inhibition. In conclusion, our results suggest that sigma-1 receptor agonists directly inhibit Na(V1.2/1.4 channels and that these interactions should be given special attention for future sigma-1 receptor function studies.

  15. Adverse reactions of α2-adrenoceptor agonists in cats reported in 2003-2013 in Finland.

    Science.gov (United States)

    Raekallio, Marja R; Virtanen, Marika; Happonen, Irmeli; Vainio, Outi M

    2017-07-01

    To describe suspected adverse drug reactions in cats associated with use of α 2 -adrenoceptor agonists. Retrospective study. A total of 90 cats. Data were collected from reports on adverse reactions to veterinary medicines sent to the Finnish Medicines Agency during 2003-2013. All reports of suspected adverse reactions associated with use of α 2 -adrenoceptor agonists in cats were included. Probable pulmonary oedema was diagnosed based on post mortem or radiological examination, or presence of frothy or excess fluid from the nostrils or trachea. If only dyspnoea and crackles on auscultation were reported, possible pulmonary oedema was presumed. Pulmonary oedema was suspected in 61 cases. Of these cats, 37 were categorised as probable and 24 as possible pulmonary oedema. The first clinical signs had been noted between 1 minute and 2 days (median, 15 minutes) after α 2 -adrenoceptor agonist administration. Many cats probably had no intravenous overhydration when the first clinical signs were detected, as either they presumably had no intravenous cannula or the signs appeared before, during or immediately after cannulation. Of the 61 cats, 43 survived, 14 died and for four the outcome was not clearly stated. Pulmonary oedema is a perilous condition that may appear within minutes of an intramuscular administration of sedative or anaesthetic agent in cats. The symptoms were not caused by intravenous overhydration, at least in cats having no venous cannula when the first clinical signs were detected. Copyright © 2017 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.

  16. Suboxone (buprenorphine/naloxone) as an agonist opioid treatment in Spain: a budgetary impact analysis.

    Science.gov (United States)

    Martínez-Raga, José; González Saiz, Francisco; Pascual, César; Casado, Miguel A; Sabater Torres, Francisco J

    2010-01-01

    To evaluate the economic impact of buprenorphine/naloxone (B/N) as an agonist opioid treatment for opiate dependence. A budgetary impact analysis model was designed to calculate the annual costs (drugs and associated costs) to the Spanish National Healthcare System of methadone versus B/N. Data for the model were obtained from official databases and expert panel opinion. It was estimated that 86,017 patients would be in an agonist opioid treatment program each of the 3 years of the study. No increase in the number of patients is expected with the introduction of B/N combination. The budgetary impact (drugs and associated costs) for agonist opiate treatment in the first year of the study would be 89.53 million EUR. In the first year of B/N use, the budgetary impact would rise by 4.39 million EUR (4.6% of the total impact), with an incremental cost of 0.79 million EUR (0.9% of the total impact). The budgetary increase would be 0.6% (0.48 million EUR increase) and 0.6% (0.49 million EUR increase) in the second and third years of use, respectively. The mean cost per patient in the first year with and without B/N would be EUR 1,050 and 1,041, respectively. The most influential variables in the sensitivity analysis were logistics and production costs of methadone and the percentage use of B/N. With an additional cost of only EUR 9 per patient, B/N is an efficient addition to the therapeutic arsenal in the drug treatment of opiate dependence, particularly when considering clinical aspects of novel pharmacotherapy. Copyright 2009 S. Karger AG, Basel.

  17. Endomorphin-2: a biased agonist at the μ-opioid receptor.

    Science.gov (United States)

    Rivero, Guadalupe; Llorente, Javier; McPherson, Jamie; Cooke, Alex; Mundell, Stuart J; McArdle, Craig A; Rosethorne, Elizabeth M; Charlton, Steven J; Krasel, Cornelius; Bailey, Christopher P; Henderson, Graeme; Kelly, Eamonn

    2012-08-01

    Previously we correlated the efficacy for G protein activation with that for arrestin recruitment for a number of agonists at the μ-opioid receptor (MOPr) stably expressed in HEK293 cells. We suggested that the endomorphins (endomorphin-1 and -2) might be biased toward arrestin recruitment. In the present study, we investigated this phenomenon in more detail for endomorphin-2, using endogenous MOPr in rat brain as well as MOPr stably expressed in HEK293 cells. For MOPr in neurons in brainstem locus ceruleus slices, the peptide agonists [d-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (DAMGO) and endomorphin-2 activated inwardly rectifying K(+) current in a concentration-dependent manner. Analysis of these responses with the operational model of pharmacological agonism confirmed that endomorphin-2 had a much lower operational efficacy for G protein-mediated responses than did DAMGO at native MOPr in mature neurons. However, endomorphin-2 induced faster desensitization of the K(+) current than did DAMGO. In addition, in HEK293 cells stably expressing MOPr, the ability of endomorphin-2 to induce phosphorylation of Ser375 in the COOH terminus of the receptor, to induce association of arrestin with the receptor, and to induce cell surface loss of receptors was much more efficient than would be predicted from its efficacy for G protein-mediated signaling. Together, these results indicate that endomorphin-2 is an arrestin-biased agonist at MOPr and the reason for this is likely to be the ability of endomorphin-2 to induce greater phosphorylation of MOPr than would be expected from its ability to activate MOPr and to induce activation of G proteins.

  18. Preventing or attenuating amphotericin B nephrotoxicity with dopamine receptor agonists: a literature review

    Directory of Open Access Journals (Sweden)

    Iman Karimzadeh

    2016-09-01

    Full Text Available Nephrotoxicity is generally considered as the most clinically significant and dose-limiting adverse reaction of amphotericin B. Currently, only the clinical effectiveness of salt loading and administering lipid formulations of amphotericin B have been clearly demonstrated to prevent its nephrotoxicity. In this review, we collected the published data related to dopamine receptor agonists in preventing amphotericin B nephrotoxicity. A literature search was conducted by the relevant keywords like ‘‘amphotericin B”, “nephrotoxicity’’, and ‘‘dopamine’’in databases such as Scopus, Medline, Embase and ISI Web of Knowledge. Four relevant articles were considered. Results of all the 3 experimental studies demonstrated that co-administration of dopamine (0.5-10 μg/kg/min as continuous intravenous infusion, SK&F R-105058, a prodrug of fenoldopam (10 mg/kg twice daily, orally or fenoldopam, a relatively selective dopamine receptor type 1 agonist, (0.5 or 1 μg/kg/min as continuous intravenous infusion can at least significantly mitigate the decrease in creatinine clearance caused by amphotericin B. Furthermore, fenoldopam and SK&F R-105058 can also protect against or delay amphotericin B-induced tubular damage. In contrast, the only clinical trial published until now found that simultaneous continuous intravenous infusion of low dose dopamine (3 μg/kg/min had no beneficial effect on the incidence, severity and time onset of developing amphotericin B-induced nephrotoxicity in autologous bone marrow transplant and leukemia patients. Considering the lack of beneficial effects in different settings such as acute kidney injury of any cause, negative results of the only clinical trial, and risk of significant adverse reactions, continuous intravenous infusion of low dose dopamine (1-3 μg/kg/min or selective dopamine receptor type 1 agonists (e.g., fenoldopam currently appears to have no promising clinical role in preventing or attenuating

  19. Vγ9Vδ2 T cell activation by strongly agonistic nucleotidic phosphoantigens.

    Science.gov (United States)

    Moulin, Morgane; Alguacil, Javier; Gu, Siyi; Mehtougui, Asmaa; Adams, Erin J; Peyrottes, Suzanne; Champagne, Eric

    2017-12-01

    Human Vγ9Vδ2 T cells can sense through their TCR tumor cells producing the weak endogenous phosphorylated antigen isopentenyl pyrophosphate (IPP), or bacterially infected cells producing the strong agonist hydroxyl dimethylallyl pyrophosphate (HDMAPP). The recognition of the phosphoantigen is dependent on its binding to the intracellular B30.2 domain of butyrophilin BTN3A1. Most studies have focused on pyrophosphate phosphoantigens. As triphosphate nucleotide derivatives are naturally co-produced with IPP and HDMAPP, we analyzed their specific properties using synthetic nucleotides derived from HDMAPP. The adenylated, thymidylated and uridylated triphosphate derivatives were found to activate directly Vγ9Vδ2 cell lines as efficiently as HDMAPP in the absence of accessory cells. These antigens were inherently resistant to terminal phosphatases, but apyrase, when added during a direct stimulation of Vγ9Vδ2 cells, abrogated their stimulating activity, indicating that their activity required transformation into strong pyrophosphate agonists by a nucleotide pyrophosphatase activity which is present in serum. Tumor cells can be sensitized with nucleotide phosphoantigens in the presence of apyrase to become stimulatory, showing that this can occur before their hydrolysis into pyrophosphates. Whereas tumors sensitized with HDMAPP rapidly lost their stimulatory activity, sensitization with nucleotide derivatives, in particular with the thymidine derivative, induced long-lasting stimulating ability. Using isothermal titration calorimetry, binding of some nucleotide derivatives to BTN3A1 intracellular domain was found to occur with an affinity similar to that of IPP, but much lower than that of HDMAPP. Thus, nucleotide phosphoantigens are precursors of pyrophosphate antigens which can deliver strong agonists intracellularly resulting in prolonged and strengthened activity.

  20. Long acting β2-agonist and corticosteroid restore airway glandular cell function altered by bacterial supernatant

    Directory of Open Access Journals (Sweden)

    Nawrocki-Raby Béatrice

    2010-01-01

    Full Text Available Abstract Background Staphylococcus aureus releases virulence factors (VF that may impair the innate protective functions of airway cells. The aim of this study was to determine whether a long-acting β2 adrenergic receptor agonist (salmeterol hydroxynaphthoate, Sal combined with a corticosteroid (fluticasone propionate, FP was able to regulate ion content and cytokine expression by airway glandular cells after exposure to S. aureus supernatant. Methods A human airway glandular cell line was incubated with S. aureus supernatant for 1 h and then treated with the combination Sal/FP for 4 h. The expression of actin and CFTR proteins was analyzed by immunofluorescence. Videomicroscopy was used to evaluate chloride secretion and X-ray microanalysis to measure the intracellular ion and water content. The pro-inflammatory cytokine expression was assessed by RT-PCR and ELISA. Results When the cells were incubated with S. aureus supernatant and then with Sal/FP, the cellular localisation of CFTR was apical compared to the cytoplasmic localisation in cells incubated with S. aureus supernatant alone. The incubation of airway epithelial cells with S. aureus supernatant reduced by 66% the chloride efflux that was fully restored by Sal/FP treatment. We also observed that Sal/FP treatment induced the restoration of ion (Cl and S and water content within the intracellular secretory granules of airway glandular cells and reduced the bacterial supernatant-dependent increase of pro-inflammatory cytokines IL8 and TNFα. Conclusions Our results demonstrate that treatment with the combination of a corticosteroid and a long-acting β2 adrenergic receptor agonist after bacterial infection restores the airway glandular cell function. Abnormal mucus induced by defective ion transport during pulmonary infection could benefit from treatment with a combination of β2 adrenergic receptor agonist and glucocorticoid.

  1. Treatment of type 2 diabetes by free Fatty Acid receptor agonists

    DEFF Research Database (Denmark)

    Watterson, Kenneth R; Hudson, Brian D; Ulven, Trond

    2014-01-01

    been developed as potential treatments for type 2 diabetes (T2D). In particular, clinical studies show that Fasiglifam, an agonist of the long-chain FFA receptor, FFA1, improved glycemic control and reduced HbA1c levels in T2D patients, with a reduced risk of hypoglycemia. However, this ligand...... was removed from clinical trials due to potential liver toxicity and determining if this is a target or a ligand-specific feature is now of major importance. Pre-clinical studies also show that FFA4 agonism increases insulin sensitivity, induces weight loss, and reduces inflammation and the metabolic and anti...

  2. Gonadotrophin-Releasing Hormone Agonists and Other Contraceptive Medications in Exotic Companion Animals.

    Science.gov (United States)

    Schoemaker, Nico J

    2018-05-01

    The use of a gonadotrophin-releasing hormone agonist slow-release implant (GnRH A-SRI) has become increasingly popular as an alternative for surgical contraception in many species. Although these implants have proven to be very effective in some species (eg, ferrets, rats, chicken, psittacines, and iguanas), they have been found less effective in other species (eg, male guinea pigs and rabbits, veiled chameleons, slider turtles, and leopard geckos). This review provides an overview of the available literature on the effects of GnRH A-SRIs in companion exotic animals. Copyright © 2018 Elsevier Inc. All rights reserved.

  3. The melatonin receptor agonist ramelteon effectively treats insomnia and behavioral symptoms in autistic disorder.

    Science.gov (United States)

    Kawabe, Kentaro; Horiuchi, Fumie; Oka, Yasunori; Ueno, Shu-Ichi

    2014-01-01

    Children with autism spectrum disorders (ASD), including autistic disorder, frequently suffer from comorbid sleep problems. An altered melatonin rhythm is considered to underlie the impairment in sleep onset and maintenance in ASD. We report three cases with autistic disorder in whom nocturnal symptoms improved with ramelteon, a selective melatonin receptor agonist. Insomnia and behavior, assessed using the Clinical Global Impression-Improvement Scale, improved in two cases with 2 mg ramelteon and in the third case with 8 mg ramelteon. Our findings demonstrate that ramelteon is effective not only for insomnia, but for behavioral problems as well, in patients with autistic disorder.

  4. Evaluation of Computational Docking to Identify Pregnane X Receptor Agonists in the ToxCast Database

    OpenAIRE

    Kortagere, Sandhya; Krasowski, Matthew D.; Reschly, Erica J.; Venkatesh, Madhukumar; Mani, Sridhar; Ekins, Sean

    2010-01-01

    Background The pregnane X receptor (PXR) is a key transcriptional regulator of many genes [e.g., cytochrome P450s (CYP2C9, CYP3A4, CYP2B6), MDR1] involved in xenobiotic metabolism and excretion. Objectives As part of an evaluation of different approaches to predict compound affinity for nuclear hormone receptors, we used the molecular docking program GOLD and a hybrid scoring scheme based on similarity weighted GoldScores to predict potential PXR agonists in the ToxCast database of pesticides...

  5. Conformational variability of the glycine receptor M2 domain in response to activation by different agonists

    DEFF Research Database (Denmark)

    Pless, Stephan Alexander; Dibas, Mohammed I; Lester, Henry A

    2007-01-01

    change. Although taurine and beta-alanine were weak partial agonists at the alpha1R19'C glycine receptor, they induced large fluorescence changes. Propofol, which drastically enhanced these currents, did not induce a glycine-like blue shift in the spectral emission peak. The inhibitors strychnine...... and picrotoxin elicited fluorescence and current changes as expected for a competitive antagonist and an open channel blocker, respectively. Glycine and taurine (or beta-alanine) also produced an increase and a decrease, respectively, in the fluorescence of a label attached to the nearby L22'C residue. Thus...

  6. Prediction of selective estrogen receptor beta agonist using open data and machine learning approach

    Directory of Open Access Journals (Sweden)

    Niu AQ

    2016-07-01

    for the classification of selective ER-β agonists. Chemistry Development Kit extended fingerprints and MACCS fingerprint performed better in structural representation between active and inactive agonists. Conclusion: These results demonstrate that combining the fingerprint and ML approaches leads to robust ER-β agonist prediction models, which are potentially applicable to the identification of selective ER-β agonists. Keywords: estrogen receptor subtype β, selective estrogen receptor modulators, quantitative structure-activity relationship models, machine learning approach

  7. Receptor structure-based discovery of non-metabolite agonists for the succinate receptor GPR91

    DEFF Research Database (Denmark)

    Trauelsen, Mette; Rexen Ulven, Elisabeth; Hjorth, Siv A

    2017-01-01

    therefore binds in a very different mode than generally believed. Importantly, an empty side-pocket is identified next to the succinate binding site. All this information formed the basis for a substructure-based search query, which, combined with molecular docking, was used in virtual screening of the ZINC...... database to pick two serial mini-libraries of a total of only 245 compounds from which sub-micromolar, selective GPR91 agonists of unique structures were identified. The best compounds were backbone-modified succinate analogs in which an amide-linked hydrophobic moiety docked into the side-pocket next...

  8. The effects of a slow release GnRH agonist implant on male rabbits

    DEFF Research Database (Denmark)

    Goericke-Pesch, Sandra Kathrin; Groeger, Gesa; Wehrend, Axel

    2015-01-01

    Surgical castration is done in male pet rabbits for reproduction control, to reduce inter-male aggression and to control hyper-sexuality, territory marking and aggression against humans. Alternatives to surgical castration are requested because of a relatively great anaesthetic risk in rabbits....... Long-term application of a GnRH agonist implant results in a fully reversible "hormonal" castration in male dogs, cats, boars and many other species. Therefore, the present study using New Zealand White hybrid and German Giant rabbits aimed to investigate the effects of a 4.7mg deslorelin implant...

  9. Bilateral deficit in explosive force production is not caused by changes in agonist neural drive.

    Directory of Open Access Journals (Sweden)

    Matthew W Buckthorpe

    Full Text Available Bilateral deficit (BLD describes the phenomenon of a reduction in performance during synchronous bilateral (BL movements when compared to the sum of identical unilateral (UL movements. Despite a large body of research investigating BLD of maximal voluntary force (MVF there exist a paucity of research examining the BLD for explosive strength. Therefore, this study investigated the BLD in voluntary and electrically-evoked explosive isometric contractions of the knee extensors and assessed agonist and antagonist neuromuscular activation and measurement artefacts as potential mechanisms. Thirteen healthy untrained males performed a series of maximum and explosive voluntary contractions bilaterally (BL and unilaterally (UL. UL and BL evoked twitch and octet contractions were also elicited. Two separate load cells were used to measure MVF and explosive force at 50, 100 and 150 ms after force onset. Surface EMG amplitude was measured from three superficial agonists and an antagonist. Rate of force development (RFD and EMG were reported over consecutive 50 ms periods (0-50, 50-100 and 100-150 ms. Performance during UL contractions was compared to combined BL performance to measure BLD. Single limb performance during the BL contractions was assessed and potential measurement artefacts, including synchronisation of force onset from the two limbs, controlled for. MVF showed no BLD (P = 0.551, but there was a BLD for explosive force at 100 ms (11.2%, P = 0.007. There was a BLD in RFD 50-100 ms (14.9%, P = 0.004, but not for the other periods. Interestingly, there was a BLD in evoked force measures (6.3-9.0%, P<0.001. There was no difference in agonist or antagonist EMG for any condition (P≥0.233. Measurement artefacts contributed minimally to the observed BLD. The BLD in volitional explosive force found here could not be explained by measurement issues, or agonist and antagonist neuromuscular activation. The BLD in voluntary and evoked explosive force

  10. Effect of α7 nicotinic acetylcholine receptor agonists and antagonists on motor function in mice

    International Nuclear Information System (INIS)

    Welch, Kevin D.; Pfister, James A.; Lima, Flavia G.; Green, Benedict T.; Gardner, Dale R.

    2013-01-01

    Nicotinic acetylcholine receptors (nAChRs) are ligand-gated cation channels found throughout the body, and serve to mediate diverse physiological functions. Muscle-type nAChRs located in the motor endplate region of muscle fibers play an integral role in muscle contraction and thus motor function. The toxicity and teratogenicity of many plants (which results in millions of dollars in losses annually to the livestock industry) are due to various toxins that bind to nAChRs including deltaline and methyllycaconitine (MLA) from larkspur (Delphinium) species, and nicotine and anabasine from tobacco (Nicotiana) species. The primary result of the actions of these alkaloids at nAChRs is neuromuscular paralysis and respiratory failure. The objective of this study was to further characterize the motor coordination deficiencies that occur upon exposure to a non-lethal dose of nAChR antagonists MLA and deltaline as well as nAChR agonists nicotine and anabasine. We evaluated the effect of nAChR agonists and antagonists on the motor function and coordination in mice using a balance beam, grip strength meter, rotarod, open field analysis and tremor monitor. These analyses demonstrated that within seconds after treatment the mice had significant loss of motor function and coordination that lasted up to 1 min, followed by a short period of quiescence. Recovery to normal muscle coordination was rapid, typically within approximately 10 min post-dosing. However, mice treated with the nAChR agonist nicotine and anabasine required a slightly longer time to recover some aspects of normal muscle function in comparison to mice treated with the nAChR antagonist MLA or deltaline. -- Highlights: ► Mice treated with nAChR agonists and antagonists have a loss in motor function. ► These deficits are temporary as near normal motor function returns within 10 min. ► There are compound-specific differences in the effects on motor function.

  11. A highly selective CCR2 chemokine agonist encoded by human herpesvirus 6

    DEFF Research Database (Denmark)

    Lüttichau, Hans R; Clark-Lewis, Ian; Jensen, Peter Østrup

    2003-01-01

    The chemokine-like, secreted protein product of the U83 gene from human herpesvirus 6, here named vCCL4, was chemically synthesized to be characterized in a complete library of the 18 known human chemokine receptors expressed individually in stably transfected cell lines. vCCL4 was found to cause...... being equally or more efficacious in causing cell migration than CCL2 and CCL7 and considerably more efficacious than CCL8 and CCL13. It is concluded that human herpesvirus 6 encodes a highly selective and efficacious CCR2 agonist, which will attract CCR2 expressing cells, for example macrophages...

  12. Chloroquine, quinine, procaine, quinidine, tricyclic antidepressants, and methylxanthines as prostaglandin agonists and antagonists.

    Science.gov (United States)

    Manku, M S; Horrobin, D F

    1976-11-20

    Chloroquine, quanine, procaine, quinidine, clomipramine, theophylline, and caffeine have been shown to be strong prostaglandin antagonists and weak agonists. The antagonist effect is clearly demonstrable at concentrations reached in human plasma when the drugs are used therapeutically. This suggests that prostaglandins are important in several situations in which their role has hitherto been unsuspected. New approaches to the development of prostaglandin antagonists and new uses for established drugs are indicated. In a preliminary study chloroquine has been successfully used to close patent ductus arteriosus in three infants.

  13. Triazolophostins: a library of novel and potent agonists of IP3 receptors

    OpenAIRE

    Vibhute, Amol M; Konieczny, Vera; Taylor, Colin William; Sureshan, Kana M

    2015-01-01

    IP3 receptors are channels that mediate the release of Ca2+ from the intracellular stores of cells stimulated by hormones or neurotransmitters. Adenophostin A (AdA) is the most potent agonist of IP3 receptors, with the β-anomeric adenine contributing to the increased potency. The potency of AdA and its stability towards the enzymes that degrade IP3 have aroused interest in AdA analogs for biological studies. The complex structure of AdA poses problems that have necessitated optimization of sy...

  14. Anxiogenic properties of an inverse agonist selective for α3 subunit-containing GABAA receptors

    OpenAIRE

    Atack, John R; Hutson, Peter H; Collinson, Neil; Marshall, George; Bentley, Graham; Moyes, Christopher; Cook, Susan M; Collins, Ian; Wafford, Keith; McKernan, Ruth M; Dawson, Gerard R

    2005-01-01

    α3IA (6-(4-pyridyl)-5-(4-methoxyphenyl)-3-carbomethoxy-1-methyl-1H-pyridin-2-one) is a pyridone with higher binding and functional affinity and greater inverse agonist efficacy for GABAA receptors containing an α3 rather than an α1, α2 or α5 subunit. If doses are selected that minimise the occupancy at these latter subtypes, then the in vivo effects of α3IA are most probably mediated by the α3 subtype.α3IA has good CNS penetration in rats and mice as measured using a [3H]Ro 15-1788 in vivo bi...

  15. Estradiol agonists inhibit human LoVo colorectal-cancer cell proliferation and migration through p53.

    Science.gov (United States)

    Hsu, Hsi-Hsien; Kuo, Wei-Wen; Ju, Da-Tong; Yeh, Yu-Lan; Tu, Chuan-Chou; Tsai, Ying-Lan; Shen, Chia-Yao; Chang, Sheng-Huang; Chung, Li-Chin; Huang, Chih-Yang

    2014-11-28

    To investigate the effects of 17β-estradiol via estrogen receptors (ER) or direct administration of ER agonists on human colorectal cancer. LoVo cells were established from the Bioresource Collection and Research Center and cultured in phenol red-free DMEM (Sigma, United States). To investigate the effects of E2 and/or ER selective agonists on cellular proliferation, LoVo colorectal cells were treated with E2 or ER-selective agonists for 24 h and 48 h and subjected to the MTT (Sigma) assay to find the concentration. And investigate the effects of E2 and/or ER selective agonists on cell used western immunoblotting to find out the diversification of signaling pathways. In order to observe motility and migration the wound healing assay and a transwell chamber (Neuro Probe) plate were tased. For a quantitative measure, we counted the number of migrating cells to the wound area post-wounding for 24 h. We further examined the cellular migration-regulating factors urokinase-type plasminogen activator (u-PA), tissue-type plasminogen activator (t-PA) and matrix metalloproteinase (MMP)-9 in human LoVo cells so gelatin zymography that we used and gelatinolytic activity was visualized by Coomassie blue staining. And these results are presented as means ± SE, and statistical comparisons were made using Student's t-test. The structure was first compared with E2 and ER agonists. We then treated the LoVo cells with E2 and ER agonists (10(-8) mol/L) for 24 h and 48 h and subsequently measured the cell viability using MTT assay. Our results showed that treatment with 17β-estradiol and/or ER agonists in human LoVo colorectal cancer cells activated p53 and then up-regulated p21 and p27 protein levels, subsequently inhibiting the downstream target gene, cyclin D1, which regulates cell proliferation. Taken together, our findings demonstrate the anti-tumorigenesis effects of 17β-estradiol and/or ER agonists and suggest that these compounds may prove to be a potential alternative

  16. Chronic β2 -adrenoceptor agonist treatment alters muscle proteome and functional adaptations induced by high intensity training in young men.

    Science.gov (United States)

    Hostrup, Morten; Onslev, Johan; Jacobson, Glenn A; Wilson, Richard; Bangsbo, Jens

    2018-01-15

    While several studies have investigated the effects of exercise training in human skeletal muscle and the chronic effect of β 2 -agonist treatment in rodent muscle, their effects on muscle proteome signature with related functional measures in humans are still incompletely understood. Herein we show that daily β 2 -agonist treatment attenuates training-induced enhancements in exercise performance and maximal oxygen consumption, and alters muscle proteome signature and phenotype in trained young men. Daily β 2 -agonist treatment abolished several of the training-induced enhancements in muscle oxidative capacity and caused a repression of muscle metabolic pathways; furthermore, β 2 -agonist treatment induced a slow-to-fast twitch muscle phenotype transition. The present study indicates that chronic β 2 -agonist treatment confounds the positive effect of high intensity training on exercise performance and oxidative capacity, which is of interest for the large proportion of persons using inhaled β 2 -agonists on a daily basis, including athletes. Although the effects of training have been studied for decades, data on muscle proteome signature remodelling induced by high intensity training in relation to functional changes in humans remains incomplete. Likewise, β 2 -agonists are frequently used to counteract exercise-induced bronchoconstriction, but the effects β 2 -agonist treatment on muscle remodelling and adaptations to training are unknown. In a placebo-controlled parallel study, we randomly assigned 21 trained men to 4 weeks of high intensity training with (HIT+β 2 A) or without (HIT) daily inhalation of β 2 -agonist (terbutaline, 4 mg dose -1 ). Of 486 proteins identified by mass-spectrometry proteomics of muscle biopsies sampled before and after the intervention, 32 and 85 were changing (false discovery rate (FDR) ≤5%) with the intervention in HIT and HIT+β 2 A, respectively. Proteome signature changes were different in HIT and HIT+β 2 A (P

  17. Association of opioid agonist therapy with lower incidence of hepatitis C virus infection in young adult injection drug users.

    Science.gov (United States)

    Tsui, Judith I; Evans, Jennifer L; Lum, Paula J; Hahn, Judith A; Page, Kimberly

    2014-12-01

    Injection drug use is the primary mode of transmission for hepatitis C virus (HCV) infection. Prior studies suggest opioid agonist therapy may reduce the incidence of HCV infection among injection drug users; however, little is known about the effects of this therapy in younger users. To evaluate whether opioid agonist therapy was associated with a lower incidence of HCV infection in a cohort of young adult injection drug users. Observational cohort study conducted from January 3, 2000, through August 21, 2013, with quarterly interviews and blood sampling. We recruited young adult (younger than 30 years) injection drug users who were negative for anti-HCV antibody and/or HCV RNA. Substance use treatment within the past 3 months, including non-opioid agonist forms of treatment, opioid agonist (methadone hydrochloride or buprenorphine hydrochloride) detoxification or maintenance therapy, or no treatment. Incident HCV infection documented with a new positive result for HCV RNA and/or HCV antibodies. Cumulative incidence rates (95% CI) of HCV infection were calculated assuming a Poisson distribution. Cox proportional hazards regression models were fit adjusting for age, sex, race, years of injection drug use, homelessness, and incarceration. Baseline characteristics of the sample (n = 552) included median age of 23 (interquartile range, 20-26) years; 31.9% female; 73.1% white; 39.7% who did not graduate from high school; and 69.2% who were homeless. During the observation period of 680 person-years, 171 incident cases of HCV infection occurred (incidence rate, 25.1 [95% CI, 21.6-29.2] per 100 person-years). The rate ratio was significantly lower for participants who reported recent maintenance opioid agonist therapy (0.31 [95% CI, 0.14-0.65]; P = .001) but not for those who reported recent non-opioid agonist forms of treatment (0.63 [95% CI, 0.37-1.08]; P = .09) or opioid agonist detoxification (1.45 [95% CI, 0.80-2.69]; P = .23). After adjustment for

  18. Comparison of the release of microRNAs and extracellular vesicles from platelets in response to different agonists.

    Science.gov (United States)

    Ambrose, Ashley R; Alsahli, Mohammed A; Kurmani, Sameer A; Goodall, Alison H

    2018-07-01

    On activation platelets release microRNAs and extracellular vesicles (EV) into circulation. The release of EV from platelets has been shown to be dependent on the agonist; in this study, we investigated whether the microRNA profile or EV released from platelets was also agonist specific. Washed platelets from healthy subjects were maximally stimulated with agonists specific for the receptors for collagen (Glycoprotein VI (GPVI)), thrombin (PAR1/PAR4), or ADP (P2Y1/P2Y12) with/without inhibiting secondary mediators, using aspirin to block cyclooxygenase-1 and apyrase to remove ADP. The released microRNAs were profiled using TaqMan microRNA microarray cards. Platelet-derived EV (pdEV) were characterized by size (Nanoparticle Tracking Analysis, NTA), for procoagulant activity (Annexin-V binding and support of thrombin generation), and for the EV markers CD63 and HSP70. Platelet activation triggered the release of 57-79 different microRNAs, dependent upon agonist, with a core of 46 microRNAs observed with all agonists. There was a high level of correlation between agonists (r 2  > 0.98; p  0.98; p < 0.0001). The 46 microRNAs seen in all samples are predicted to have significant effects on the translation of proteins involved in endocytosis, cell cycle control, and differentiation. MiR-223-3p was the most abundant in all samples and has previously been implicated in myeloid lineage development and demonstrated to have anti-inflammatory effects. Stimulation through GPVI produced a pdEV population with significantly more procoagulant activity than the other agonists. Apyrase significantly reduced microRNA and pdEV release, while aspirin had little effect. These data suggest that all tested agonists trigger the release of a similar microRNA profile while the procoagulant activity of the pdEV was agonist dependent. ADP was shown to play an important role in the release of both microRNAs and pdEV.

  19. Modulation of in vivo immunoglobulin production by endogenous histamine and H1R and H2R agonists and antagonists.

    Science.gov (United States)

    Tripathi, Trivendra; Shahid, Mohammad; Khan, Haris M; Negi, Mahendra Pal Singh; Siddiqui, Mashiatullah; Khan, Rahat A

    2010-01-01

    The present study was designed to delineate the immunomodulatory role of histamine receptors (H1R and H2R) and their antibody generation in a rabbit model. Six groups containing 18 rabbits each received either vehicle (sterile distilled water, 1 ml/kg x b.i.d), histamine (100 μg/kg x b.i.d.), H1R agonist (HTMT, 10 μg/kg x b.i.d.), H2R agonist (amthamine, 10 μg/kg x b.i.d.), H1R antagonist (pheniramine, 10 mg/kg x b.i.d.) or H2R antagonist (ranitidine, 10 mg/kg x b.i.d.). All animals were subsequently immunized with an intravenous injection of sheep red blood cells (SRBC). Estimations of total serum immunoglobulins (Igs), immunoglobulin M (IgM) and immunoglobulin G (IgG) were performed by ELISA and hemagglutination assay (HA) at days 0 (pre-immunization), 7, 14, 21, 28 and 58 (post-immunization). Both the ELISA and the HA showed similar production of Igs, IgM and IgG but the results were found comparatively more significant by ELISA as opposed to HA. Results showed that histamine could influence a detectable antibody response to SRBC early (i.e., at day 7), which lasted until day 58. Immunomodulatory processes showed suppression of an Ig generation in the H1R-antagonist group with enhancement in the H2R-antagonist group. The H1R-agonist group showed an increased Ig production in comparison to the H2R-agonist group. The IgM production was inhibited in the H1R-antagonist group as compared to the H2R-antagonist group, and it was also suppressed in H1R-agonist group as compared to H2R-agonist group. IgG production was inhibited in the H1R-antagonist group as opposed to the H2R-antagonist group. In contrast, the H1R-agonist group increased IgG production as compared to the H2R-agonist group. All the results were found to be statistically significant (p < 0.05 or p < 0.01). In conclusion, histamine and its receptor (H1R and H2R) agonists enhance antibody production by triggering the histamine receptors (H1R and H2R), and both the H1R antagonist and the H2R antagonist

  20. Design and Synthesis of 2-Alkylpyrimidine-4,6-diol and 6-Alkylpyridine-2,4-diol as Potent GPR84 Agonists.

    Science.gov (United States)

    Liu, Yang; Zhang, Qing; Chen, Lin-Hai; Yang, Hui; Lu, Wei; Xie, Xin; Nan, Fa-Jun

    2016-06-09

    A series of alkylpyrimidine-4,6-diol derivatives were designed and synthesized as novel GRP84 agonists based on a high-throughput screening (HTS) hit 1. 6-Nonylpyridine-2,4-diol was identified as the most potent agonist of GPR84 reported so far, with an EC50 of 0.189 nM. These novel GPR84 agonists will provide valuable tools for the study of the physiological functions of GPR84.

  1. The Relative Potency of Inverse Opioid Agonists and a Neutral Opioid Antagonist in Precipitated Withdrawal and Antagonism of Analgesia and Toxicity

    OpenAIRE

    Sirohi, Sunil; Dighe, Shveta V.; Madia, Priyanka A.; Yoburn, Byron C.

    2009-01-01

    Opioid antagonists can be classified as inverse agonists and neutral antagonists. In the opioid-dependent state, neutral antagonists are significantly less potent in precipitating withdrawal than inverse agonists. Consequently, neutral opioid antagonists may offer advantages over inverse agonists in the management of opioid overdose. In this study, the relative potency of three opioid antagonists to block opioid analgesia and toxicity and precipitate withdrawal was exa...

  2. Differential immediate and sustained memory enhancing effects of alpha7 nicotinic receptor agonists and allosteric modulators in rats

    DEFF Research Database (Denmark)

    Thomsen, Morten Skøtt; El-Sayed, Mona; Mikkelsen, Jens D

    2011-01-01

    of repeated administration of α7 nAChR agonists. We further compare the effect of agonists to that of α7 nAChR positive allosteric modulators (PAMs), which do not induce upregulation of the α7 nAChR. Using the social discrimination test as a measure of short-term memory, we show that the α7 nAChR agonist A......-582941 improves short-term memory immediately after repeated (7× daily), but not a single administration. The α7 nAChR PAMs PNU-120596 and AVL-3288 do not affect short-term memory immediately after a single or repeated administration. This demonstrates a fundamental difference in the behavioral effects...... of agonists and PAMs that may be relevant for clinical development. Importantly, A-582941 and AVL-3288 increase short-term memory 24 hrs after repeated, but not a single, administration, suggesting that repeated administration of both agonists and PAMs may produce sustained effects on cognitive performance...

  3. GnRH agonist versus GnRH antagonist in in vitro fertilization and embryo transfer (IVF/ET

    Directory of Open Access Journals (Sweden)

    Depalo Raffaella

    2012-04-01

    Full Text Available Abstract Several protocols are actually available for in Vitro Fertilization and Embryo Transfer. The review summarizes the main differences and the clinic characteristics of the protocols in use with GnRH agonists and GnRH antagonists by emphasizing the major outcomes and hormonal changes associated with each protocol. The majority of randomized clinical trials clearly shows that in “in Vitro” Fertilization and Embryo Transfer, the combination of exogenous Gonadotropin plus a Gonadotropin Releasing Hormone (GnRH agonist, which is able to suppress pituitary FSH and LH secretion, is associated with increased pregnancy rate as compared with the use of gonadotropins without a GnRH agonist. Protocols with GnRH antagonists are effective in preventing a premature rise of LH and induce a shorter and more cost-effective ovarian stimulation compared to the long agonist protocol. However, a different synchronization of follicular recruitment and growth occurs with GnRH agonists than with GnRH antagonists. Future developments have to be focused on timing of the administration of GnRH antagonists, by giving a great attention to new strategies of stimulation in patients in which radio-chemotherapy cycles are needed.

  4. The effect of various opiate receptor agonists on the seizure threshold in the rat. Is dynorphin an endogenous anticonvulsant?

    Science.gov (United States)

    Przewłocka, B; Stala, L; Lasoń, W; Przewłocki, R

    1983-01-01

    The effects of various opiate receptor agonists on the seizure threshold after an intravenous infusion of pentylenetetrazol were investigated in rats. The mu- and epsilon-receptor agonists, morphine (20-40 micrograms) and beta-endorphin (5-10 micrograms) show proconvulsant properties towards clonic and tonic seizures. The delta-receptor agonist (D-Ala2,D-Leu5-enkephalin, DADL 5-40 micrograms) and alpha-neoendorphin (20-40 micrograms) show pro- and anticonvulsant properties towards clonic and tonic seizures, respectively. Anticonvulsant properties of DADL are possibly due to its action on the spinal cord, since after the intrathecal injection this effect is still observed. Similarities between DADL and alpha-neoendorphin suggest that they may act through the same receptor. The kappa-receptor agonist dynorphin A (5-20 micrograms) and its degradation-resistant analogue D-Arg-dynorphin1-13 (10 micrograms) show significant anticonvulsant properties. Our present results suggest that the kappa-receptor agonist dynorphin may act physiologically as an endogenous anticonvulsant, in contrast to other opioid peptides.

  5. Agonistic anti-TIGIT treatment inhibits T cell responses in LDLr deficient mice without affecting atherosclerotic lesion development.

    Directory of Open Access Journals (Sweden)

    Amanda C Foks

    Full Text Available OBJECTIVE: Co-stimulatory and co-inhibitory molecules are mainly expressed on T cells and antigen presenting cells and strongly orchestrate adaptive immune responses. Whereas co-stimulatory molecules enhance immune responses, signaling via co-inhibitory molecules dampens the immune system, thereby showing great therapeutic potential to prevent cardiovascular diseases. Signaling via co-inhibitory T cell immunoglobulin and ITIM domain (TIGIT directly inhibits T cell activation and proliferation, and therefore represents a novel therapeutic candidate to specifically dampen pro-atherogenic T cell reactivity. In the present study, we used an agonistic anti-TIGIT antibody to determine the effect of excessive TIGIT-signaling on atherosclerosis. METHODS AND RESULTS: TIGIT was upregulated on CD4(+ T cells isolated from mice fed a Western-type diet in comparison with mice fed a chow diet. Agonistic anti-TIGIT suppressed T cell activation and proliferation both in vitro and in vivo. However, agonistic anti-TIGIT treatment of LDLr(-/- mice fed a Western-type diet for 4 or 8 weeks did not affect atherosclerotic lesion development in comparison with PBS and Armenian Hamster IgG treatment. Furthermore, elevated percentages of dendritic cells were observed in the blood and spleen of agonistic anti-TIGIT-treated mice. Additionally, these cells showed an increased activation status but decreased IL-10 production. CONCLUSIONS: Despite the inhibition of splenic T cell responses, agonistic anti-TIGIT treatment does not affect initial atherosclerosis development, possibly due to increased activity of dendritic cells.

  6. Effect of adrenaline and alpha-agonists on net rate of liquid absorption from the pleural space of rabbits.

    Science.gov (United States)

    Zocchi, L; Raffaini, A; Agostoni, E

    1997-05-01

    Indirect evidence supporting a solute-coupled liquid absorption from the pleural space of rabbits has recently been provided; moreover, the beta 2-adrenoceptor agonist terbutaline has been found to increase this absorption. In this study the effect of adrenaline and alpha-adrenoceptor agonists on net rate of liquid absorption (Jnet) from albumin Ringer hydrothoraces of various sizes has been determined in anaesthetized rabbits. In hydrothoraces with adrenaline (5 x 10(-6) M) the relationship between Jnet and volume of liquid injected was displaced upwards by 0.09 ml h-1 relative to that in control hydrothoraces (P liquid absorption, since beta-agonists inhibit lymphatic activity while, at relatively high concentrations, they may increase active transport. Conversely, the strong stimulation of lymphatic alpha-receptors that should occur with adrenaline after beta-blockade may fail to increase lymphatic drainage, because it has been shown that the increase in contraction frequency of lymphatics may be balanced by the decrease in their stroke volume. Arterial blood pressure during the hydrothoraces with adrenaline was unchanged. In hydrothoraces with the alpha 2-agonist clonidine (5 x 10(-6) M; a less potent agent than adrenaline) the slope of the relationship between Jnet and volume injected increased by 26% (P liquid load. In hydrothoraces with the alpha 1-agonist phenylephrine (5 x 10(-6) or 10(-7) M) Jnet was simlar to control values.

  7. Conversion of agonist site to metal-ion chelator site in the beta(2)-adrenergic receptor

    DEFF Research Database (Denmark)

    Elling, C E; Thirstrup, K; Holst, Birgitte

    1999-01-01

    Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the beta(2)-adrenergic receptor,...... as generic, pharmacologic tools to switch 7TM receptors with engineered metal-ion sites on or off at will.......Previously metal-ion sites have been used as structural and functional probes in seven transmembrane receptors (7TM), but as yet all the engineered sites have been inactivating. Based on presumed agonist interaction points in transmembrane III (TM-III) and -VII of the beta(2)-adrenergic receptor......, in this paper we construct an activating metal-ion site between the amine-binding Asp-113 in TM-III-or a His residue introduced at this position-and a Cys residue substituted for Asn-312 in TM-VII. No increase in constitutive activity was observed in the mutant receptors. Signal transduction was activated...

  8. Regulation of Serum Response Factor and Adiponectin by PPARγ Agonist Docosahexaenoic Acid

    Directory of Open Access Journals (Sweden)

    Clayton Johnson

    2011-01-01

    Full Text Available Recent studies indicate that significant health benefits involving the regulation of signaling proteins result from the consumption of omega-3 polyunsaturated fatty acids (ω-3 PUFAs. Serum response factor (SRF is involved in transcriptional regulation of muscle growth and differentiation. SRF levels are increased in the aging heart muscle. It has not been examined whether SRF is made by adipocytes and whether SRF secretion by adipocytes is modulated by PPARγ agonist DHA. Adiponectin is made exclusively by adipocytes. We and others have previously reported that PUFAs such as DHA increase adiponectin levels and secretion in adipocytes. Here we show that DHA downregulates SRF with a simultaneous upregulation of adiponectin and that both these responses are reversible by PPARγ antagonist. Furthermore, there appears to be a direct relationship between DHA exposure and increased levels of membrane-associated high-density adiponectin, as well as lower levels of membrane-associated SRF. Thus, we find that the levels of SRF and adiponectin are inversely related in response to treatment with PPARγ agonist DHA. Decreased levels of SRF along with increase in membrane-associated adiponectin could in part mediate the health benefits of DHA.

  9. The risky business of dopamine agonists in Parkinson disease and impulse control disorders.

    Science.gov (United States)

    Claassen, Daniel O; van den Wildenberg, Wery P M; Ridderinkhof, K Richard; Jessup, Charles K; Harrison, Madaline B; Wooten, G Frederick; Wylie, Scott A

    2011-08-01

    Risk-taking behavior is characterized by pursuit of reward in spite of potential negative consequences. Dopamine neurotransmission along the mesocorticolimbic pathway is a potential modulator of risk behavior. In patients with Parkinson's disease (PD), impulse control disorder (ICD) can result from dopaminergic medication use, particularly dopamine agonists (DAA). Behaviors associated with ICD include hypersexuality as well as compulsive gambling, shopping, and eating, and these behaviors are potentially linked to alterations to risk processing. Using the Balloon Analogue Risk Task, we assessed the role of agonist therapy on risk-taking behavior in PD patients with (n = 22) and without (n = 19) active ICD symptoms. Patients performed the task both "on" and "off" DAA. DAA increased risk-taking in PD patients with active ICD symptoms, but it did not affect risk behavior of PD controls. DAA dose was also important in explaining risk behavior. Both groups similarly reduced their risk-taking in high compared to low risk conditions and following the occurrence of a negative consequence, suggesting that ICD patients do not necessarily differ in their abilities to process and adjust to some aspects of negative consequences. Our findings suggest dopaminergic augmentation of risk-taking behavior as a potential contributing mechanism for the emergence of ICD in PD patients. (PsycINFO Database Record (c) 2011 APA, all rights reserved).

  10. Agonizing care: care ethics, agonistic feminism and a political theory of care.

    Science.gov (United States)

    Cloyes, Kristin G

    2002-09-01

    'Care' is central to nursing theory and practice, and has been described in a variety of ways. Intense conversations about care have been developing in other fields of study as well, from the social sciences to the humanities. Care ethics has grown out of intellectual exchange between feminist thought, moral theory and the critique of traditional western political philosophy. However, care ethics is not without its critics, as these accounts of care have also sparked vigorous challenges. This paper traces the construct of care through nursing theory, care ethics, feminist critiques of moral and political theory and agonistic feminism to outline a set of problematics that a political theory of care should engage. It discusses how care is conventionally posited in more or less essentialist, universalizing and naturalizing terms. It introduces the ideas of feminist theorists who resist dichotomizing care and the political, and situate care in the context of power and politics. The tensions between care feminism and agonistic feminism are highlighted in order to explore the potential of theorizing both care and nursing in political terms.

  11. Structural Determinants for the Binding of Morphinan Agonists to the μ-Opioid Receptor.

    Directory of Open Access Journals (Sweden)

    Xiaojing Cong

    Full Text Available Atomistic descriptions of the μ-opioid receptor (μOR noncovalently binding with two of its prototypical morphinan agonists, morphine (MOP and hydromorphone (HMP, are investigated using molecular dynamics (MD simulations. Subtle differences between the binding modes and hydration properties of MOP and HMP emerge from the calculations. Alchemical free energy perturbation calculations show qualitative agreement with in vitro experiments performed in this work: indeed, the binding free energy difference between MOP and HMP computed by forward and backward alchemical transformation is 1.2±1.1 and 0.8±0.8 kcal/mol, respectively, to be compared with 0.4±0.3 kcal/mol from experiment. Comparison with an MD simulation of μOR covalently bound with the antagonist β-funaltrexamine hints to agonist-induced conformational changes associated with an early event of the receptor's activation: a shift of the transmembrane helix 6 relative to the transmembrane helix 3 and a consequent loss of the key R165-T279 interhelical hydrogen bond. This finding is consistent with a previous proposal suggesting that the R165-T279 hydrogen bond between these two helices indicates an inactive receptor conformation.

  12. Structural Probing and Molecular Modeling of the A₃ Adenosine Receptor: A Focus on Agonist Binding.

    Science.gov (United States)

    Ciancetta, Antonella; Jacobson, Kenneth A

    2017-03-11

    Adenosine is an endogenous modulator exerting its functions through the activation of four adenosine receptor (AR) subtypes, termed A₁, A 2A , A 2B and A₃, which belong to the G protein-coupled receptor (GPCR) superfamily. The human A₃AR (hA₃AR) subtype is implicated in several cytoprotective functions. Therefore, hA₃AR modulators, and in particular agonists, are sought for their potential application as anti-inflammatory, anticancer, and cardioprotective agents. Structure-based molecular modeling techniques have been applied over the years to rationalize the structure-activity relationships (SARs) of newly emerged A₃AR ligands, guide the subsequent lead optimization, and interpret site-directed mutagenesis (SDM) data from a molecular perspective. In this review, we showcase selected modeling-based and guided strategies that were applied to elucidate the binding of agonists to the A₃AR and discuss the challenges associated with an accurate prediction of the receptor extracellular vestibule through homology modeling from the available X-ray templates.

  13. Structural Probing and Molecular Modeling of the A3 Adenosine Receptor: A Focus on Agonist Binding

    Science.gov (United States)

    Ciancetta, Antonella; Jacobson, Kenneth A.

    2017-01-01

    Adenosine is an endogenous modulator exerting its functions through the activation of four adenosine receptor (AR) subtypes, termed A1, A2A, A2B and A3, which belong to the G protein-coupled receptor (GPCR) superfamily. The human A3AR (hA3AR) subtype is implicated in several cytoprotective functions. Therefore, hA3AR modulators, and in particular agonists, are sought for their potential application as anti-inflammatory, anticancer, and cardioprotective agents. Structure-based molecular modeling techniques have been applied over the years to rationalize the structure-activity relationships (SARs) of newly emerged A3AR ligands, guide the subsequent lead optimization, and interpret site-directed mutagenesis (SDM) data from a molecular perspective. In this review, we showcase selected modeling-based and guided strategies that were applied to elucidate the binding of agonists to the A3AR and discuss the challenges associated with an accurate prediction of the receptor extracellular vestibule through homology modeling from the available X-ray templates. PMID:28287473

  14. Structural Probing and Molecular Modeling of the A3 Adenosine Receptor: A Focus on Agonist Binding

    Directory of Open Access Journals (Sweden)

    Antonella Ciancetta

    2017-03-01

    Full Text Available Adenosine is an endogenous modulator exerting its functions through the activation of four adenosine receptor (AR subtypes, termed A1, A2A, A2B and A3, which belong to the G protein-coupled receptor (GPCR superfamily. The human A3AR (hA3AR subtype is implicated in several cytoprotective functions. Therefore, hA3AR modulators, and in particular agonists, are sought for their potential application as anti-inflammatory, anticancer, and cardioprotective agents. Structure-based molecular modeling techniques have been applied over the years to rationalize the structure–activity relationships (SARs of newly emerged A3AR ligands, guide the subsequent lead optimization, and interpret site-directed mutagenesis (SDM data from a molecular perspective. In this review, we showcase selected modeling-based and guided strategies that were applied to elucidate the binding of agonists to the A3AR and discuss the challenges associated with an accurate prediction of the receptor extracellular vestibule through homology modeling from the available X-ray templates.

  15. Procaine rapidly inactivates acetylcholine receptors from Torpedo and competes with agonist for inhibition sites

    International Nuclear Information System (INIS)

    Forman, S.A.; Miller, K.W.

    1989-01-01

    The relationship between the high-affinity procaine channel inhibition site and the agonist self-inhibition site on acetylcholine receptors (AChRs) from Torpedo electroplaque was investigated by using rapid 86 Rb + quenched-flux assays at 4 degree C in native AChR-rich vesicles on which 50-60% of ACh activation sites were blocked with α-bungarotoxin (α-BTX). In the presence of channel-activating acetylcholine (ACh) concentrations alone, AChR undergoes one phase of inactivation in under a second. Addition of procaine produces two-phase inactivation similar to that seen with self-inhibiting ACh concentrations rapid inactivation complete in 30-75 ms is followed by fast desensitization at the same k d observed without procaine. The dependence of k r on [procaine] is consistent with a bimolecular association between procaine and its AChR site. Inhibition of AChR function by mixtures of procaine plus self-inhibiting concentrations of ACh or suberyldicholine was studied by reducing the level of α-BTX block in vesicles. The data support a mechanism where procaine binds preferentially to the open-channel AChR state, since no procaine-induced inactivation is observed without agonist and k r 's dependence on [ACh] in channel-activating range closely parallels that of 86 Rb + flux response to ACh

  16. The cardiovascular safety trials of DPP-4 inhibitors, GLP-1 agonists, and SGLT2 inhibitors.

    Science.gov (United States)

    Secrest, Matthew H; Udell, Jacob A; Filion, Kristian B

    2017-04-01

    In this paper, we review the results of large, double-blind, placebo-controlled randomized trials mandated by the US Food and Drug Administration to examine the cardiovascular safety of newly-approved antihyperglycemic agents in patients with type 2 diabetes. The cardiovascular effects of dipeptidyl peptidase-4 (DPP-4) inhibitors remain controversial: while these drugs did not reduce or increase the risk of primary, pre-specified composite cardiovascular outcomes, one DPP-4 inhibitor (saxagliptin) increased the risk of hospitalization for heart failure in the overall population; another (alogliptin) demonstrated inconsistent effects on heart failure hospitalization across subgroups of patients, and a third (sitagliptin) demonstrated no effect on heart failure. Evidence for cardiovascular benefits of glucagon-like peptide-1 (GLP-1) agonists has been similarly heterogeneous, with liraglutide and semaglutide reducing the risk of composite cardiovascular outcomes, but lixisenatide having no reduction or increase in cardiovascular risk. The effect of GLP-1 agonists on retinopathy remains a potential concern. In the only completed trial to date to assess a sodium-glucose cotransporter-2 (SGLT2) inhibitor, empagliflozin reduced the risk of composite cardiovascular endpoints, predominantly through its impact on cardiovascular mortality and heart failure hospitalization. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Peripartum Cardiomyopathy Treatment with Dopamine Agonist and Subsequent Pregnancy with a Satisfactory Outcome.

    Science.gov (United States)

    Melo, Maria Adélia Medeiros E; Carvalho, Jordão Sousa; Feitosa, Francisco Edson de Lucena; Araujo Júnior, Edward; Peixoto, Alberto Borges; Costa Carvalho, Francisco Herlânio; Carvalho, Regina Coeli Marques

    2016-06-01

    Pathophysiological mechanisms of peripartum cardiomyopathy are not yet completely defined, although there is a strong association with various factors that are already known, including pre-eclampsia. Peripartum cardiomyopathy treatment follows the same recommendations as heart failure with systolic dysfunction. Clinical and experimental studies suggest that products of prolactin degradation can induce this cardiomyopathy. The pharmacological suppression of prolactin production by D2 dopamine receptor agonists bromocriptine and cabergoline has demonstrated satisfactory results in the therapeutic response to the treatment. Here we present a case of an adolescent patient in her first gestation with peripartum cardiomyopathy that evolved to the normalized left ventricular function after cabergoline administration, which was used as an adjuvant in cardiac dysfunction treatment. Subsequently, despite a short interval between pregnancies, the patient exhibited satisfactory progress throughout the entire gestation or puerperium in a new pregnancy without any cardiac alterations. Dopamine agonists that are orally used and are affordable in most tertiary centers, particularly in developing countries, should be considered when treating peripartum cardiomyopathy cases. Thieme Publicações Ltda Rio de Janeiro, Brazil.

  18. Structural and energetic effects of A2A adenosine receptor mutations on agonist and antagonist binding.

    Directory of Open Access Journals (Sweden)

    Henrik Keränen

    Full Text Available To predict structural and energetic effects of point mutations on ligand binding is of considerable interest in biochemistry and pharmacology. This is not only useful in connection with site-directed mutagenesis experiments, but could also allow interpretation and prediction of individual responses to drug treatment. For G-protein coupled receptors systematic mutagenesis has provided the major part of functional data as structural information until recently has been very limited. For the pharmacologically important A(2A adenosine receptor, extensive site-directed mutagenesis data on agonist and antagonist binding is available and crystal structures of both types of complexes have been determined. Here, we employ a computational strategy, based on molecular dynamics free energy simulations, to rationalize and interpret available alanine-scanning experiments for both agonist and antagonist binding to this receptor. These computer simulations show excellent agreement with the experimental data and, most importantly, reveal the molecular details behind the observed effects which are often not immediately evident from the crystal structures. The work further provides a distinct validation of the computational strategy used to assess effects of point-mutations on ligand binding. It also highlights the importance of considering not only protein-ligand interactions but also those mediated by solvent water molecules, in ligand design projects.

  19. Recent Advances in GLP-1 Receptor Agonists for Use in Diabetes Mellitus.

    Science.gov (United States)

    McBrayer, Dominic N; Tal-Gan, Yftah

    2017-09-01

    Preclinical Research Mimetics of Glucagon-like peptide 1 (GLP-1) represent a useful alternative or complementary treatment choice to insulin in the treatment of diabetes mellitus. The lack of hypoglycemia as a side effect when GLP-1 receptor agonists are used along with the tendency of these therapeutic agents to prevent or even reduce weight gain makes them valuable targets in therapy development. However, native GLP-1 and many of its early analogues have very short half-lives, requiring repeated treatment to maintain therapeutic levels. As all current treatments are injected subcutaneously, a large focus has been made on trying to extend the half-lives of GLP-1 analogues while retaining bioactivity. Most success in this regard has been achieved with the use of peptide-protein fusions, which are not as well suited for oral administration. However, recent work focused on the development of non-fusion peptides with increased half-lives that may be more appropriate for oral administration. This minireview discusses the structural characteristics of past and present analogues as well as the recent work conducted toward developing novel GLP-1 receptor agonists. Drug Dev Res 78 : 292-299, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  20. Design of Glucagon-Like Peptide-1 Receptor Agonist for Diabetes Mellitus from Traditional Chinese Medicine

    Directory of Open Access Journals (Sweden)

    Hsin-Chieh Tang

    2014-01-01

    Full Text Available Glucagon-like peptide-1 (GLP-1 is a promising target for diabetes mellitus (DM therapy and reduces the occurrence of diabetes due to obesity. However, GLP-1 will be hydrolyzed soon by the enzyme dipeptidyl peptidase-4 (DPP-4. We tried to design small molecular drugs for GLP-1 receptor agonist from the world's largest traditional Chinese medicine (TCM Database@Taiwan. According to docking results of virtual screening, we selected 2 TCM compounds, wenyujinoside and 28-deglucosylchikusetsusaponin IV, for further molecular dynamics (MD simulation. GLP-1 was assigned as the control compound. Based on the results of root mean square deviation (RMSD, solvent accessible surface (SAS, mean square deviation (MSD, Gyrate, total energy, root mean square fluctuation (RMSF, matrices of smallest distance of residues, database of secondary structure assignment (DSSP, cluster analysis, and distance of H-bond, we concluded that all the 3 compounds could bind and activate GLP-1 receptor by computational simulation. Wenyujinoside and 28-deglucosylchikusetsusaponin IV were the TCM compounds that could be GLP-1 receptor agonists.

  1. Diindolylmethane Derivatives: Potent Agonists of the Immunostimulatory Orphan G Protein-Coupled Receptor GPR84.

    Science.gov (United States)

    Pillaiyar, Thanigaimalai; Köse, Meryem; Sylvester, Katharina; Weighardt, Heike; Thimm, Dominik; Borges, Gleice; Förster, Irmgard; von Kügelgen, Ivar; Müller, Christa E

    2017-05-11

    The G i protein-coupled receptor GPR84, which is activated by (hydroxy)fatty acids, is highly expressed on immune cells. Recently, 3,3'-diindolylmethane was identified as a heterocyclic, nonlipid-like GPR84 agonist. We synthesized a broad range of diindolylmethane derivatives by condensation of indoles with formaldehyde in water under microwave irradiation. The products were evaluated at the human GPR84 in cAMP and β-arrestin assays. Structure-activity relationships (SARs) were steep. 3,3'-Diindolylmethanes bearing small lipophilic residues at the 5- and/or 7-position of the indole rings displayed the highest activity in cAMP assays, the most potent agonists being di(5-fluoro-1H-indole-3-yl)methane (38, PSB-15160, EC 50 80.0 nM) and di(5,7-difluoro-1H-indole-3-yl)methane (57, PSB-16671, EC 50 41.3 nM). In β-arrestin assays, SARs were different, indicating biased agonism. The new compounds were selective versus related fatty acid receptors and the arylhydrocarbon receptor. Selected compounds were further investigated and found to display an ago-allosteric mechanism of action and increased stability in comparison to the lead structure.

  2. A selective cannabinoid CB2 agonist attenuates damage and improves memory retention following stroke in mice.

    Science.gov (United States)

    Ronca, Richard D; Myers, Alyssa M; Ganea, Doina; Tuma, Ronald F; Walker, Ellen A; Ward, Sara Jane

    2015-10-01

    We have recently demonstrated that treatment with a cannabinoid CB2 agonist was protective in a mouse middle cerebral artery occlusion model of cerebral ischemia/reperfusion injury. The present study aimed to determine whether these protective effects of CB2 agonism would extend to a mouse photoinjury model of permanent ischemia and determine associated alterations in cognition and infarct size. Mice received three injections of the CB2 selective agonist O-1966 or vehicle 1h prior to and 2 and 5days following induction of stroke. Infarct size was assessed at 1, 3, or 7days post-injury and learning and memory effects of injury and O-1966 treatment were assessed on days 6 and 7 using a novel object recognition task and an operant acquisition and retention procedure. O-1966 treated mice had significantly smaller infarct volumes compared with vehicle treated mice. Photoinjury was also associated with a significant memory impairment on day 7 post-injury, and this deficit was reversed with O-1966 treatment. Surprisingly, sham-operated mice receiving O-1966 treatment showed a significant learning deficit in both the recognition and operant tasks compared with vehicle treated sham mice. We conclude that CB2 activation is protective against cognitive deficits and tissue damage following permanent ischemia, but may dysregulate glial or neuronal function of learning and memory circuits in the absence of injury and/or inflammation. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. The electrophysiological effects of the serotonin 1A receptor agonist buspirone in emotional face processing.

    Science.gov (United States)

    Bernasconi, Fosco; Kometer, Michael; Pokorny, Thomas; Seifritz, Erich; Vollenweider, Franz X

    2015-04-01

    Emotional face processing is critically modulated by the serotonergic system, and serotonin (5-HT) receptor agonists impair emotional face processing. However, the specific contribution of the 5-HT1A receptor remains poorly understood. Here we investigated the spatiotemporal brain mechanisms underpinning the modulation of emotional face processing induced by buspirone, a partial 5-HT1A receptor agonist. In a psychophysical discrimination of emotional faces task, we observed that the discrimination fearful versus neutral faces were reduced, but not happy versus neutral faces. Electrical neuroimaging analyses were applied to visual evoked potentials elicited by emotional face images, after placebo and buspirone administration. Buspirone modulated response strength (i.e., global field power) in the interval 230-248ms after stimulus onset. Distributed source estimation over this time interval revealed that buspirone decreased the neural activity in the right dorsolateral prefrontal cortex that was evoked by fearful faces. These results indicate temporal and valence-specific effects of buspirone on the neuronal correlates of emotional face processing. Furthermore, the reduced neural activity in the dorsolateral prefrontal cortex in response to fearful faces suggests a reduced attention to fearful faces. Collectively, these findings provide new insights into the role of 5-HT1A receptors in emotional face processing and have implications for affective disorders that are characterized by an increased attention to negative stimuli. Copyright © 2015 Elsevier B.V. and ECNP. All rights reserved.

  4. Sirtuin 1 Agonist Minimizes Injury and Improves the Immune Response Following Traumatic Shock.

    Science.gov (United States)

    Luciano, Jason A; Kautza, Benjamin; Darwiche, Sophie; Martinez, Silvia; Stratimirovic, Sladjana; Waltz, Paul; Sperry, Jason; Rosengart, Matthew; Shiva, Sruti; Zuckerbraun, Brian S

    2015-08-01

    Survival from traumatic injury requires a coordinated and controlled inflammatory and immune response. Mitochondrial and metabolic responses to stress have been shown to play a role in these inflammatory and immune responses. We hypothesized that increases in mitochondrial biogenesis via a sirtuin 1 agonist would decrease tissue injury and partially ameliorate the immunosuppression seen following trauma. C57Bl/6 mice were subjected to a multiple trauma model. Mice were pretreated with either 100 mg/kg per day of the sirtuin 1 agonist, Srt1720, via oral gavage for 2 days prior to trauma and extended until the day the animals were killed, or they were pretreated with peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) siRNA via hydrodynamic tail vein injection 48 h prior to trauma. Markers for mitochondrial function and biogenesis were measured in addition to splenocyte proliferative capacity and bacterial clearance. Srt1720 was noted to improve mitochondrial biogenesis, mitochondrial function, and complex IV activity following traumatic injury (P hepatic injury with significant reductions in serum alanine aminotransferase levels seen in mice treated with srt1720. Splenocyte proliferative capacity and intraperitoneal bacterial clearance were evaluated as markers for overall immune function following trauma-hemorrhage. Treatment with Srt1720 minimized the trauma-induced decreases in splenocyte proliferation (P clearance. The PGC1α signaling pathway is an important regulator of mitochondrial function and biogenesis, which can potentially be harnessed to protect against hepatic injury and minimize the immunosuppression that is seen following trauma-hemorrhage.

  5. Synthesis and SAR study of a novel series of dopamine receptor agonists

    DEFF Research Database (Denmark)

    Risgaard, R.; Jensen, M.; Jørgensen, M.

    2014-01-01

    The synthesis of a novel series of dopamine receptor agonists are described as well as their in vitro potency and efficacy on dopamine D and D receptors. This series was designed from pergolide and (4aR,10aR)-1-propyl-1,2,3,4,4a,5,10,10a-octahydro-benzo[g]quinolin-6-ol (PHBQ) and resulted in the ...... in the synthesis of (2R,4aR,10aR)-2-methylsulfanylmethyl-4-propyl-3,4,4a,5,10,10a-hexahydro-2H-naphtho[2,3-b][1,4]oxazin-9-ol (compound 27), which has a D and D receptor profile similar to that of the most recently approved drug for Parkinson's disease, rotigotine.......The synthesis of a novel series of dopamine receptor agonists are described as well as their in vitro potency and efficacy on dopamine D and D receptors. This series was designed from pergolide and (4aR,10aR)-1-propyl-1,2,3,4,4a,5,10,10a-octahydro-benzo[g]quinolin-6-ol (PHBQ) and resulted...

  6. Antibodies against the melanocortin-4 receptor act as inverse agonists in vitro and in vivo.

    Science.gov (United States)

    Peter, Jean-Christophe; Nicholson, Janet R; Heydet, Déborah; Lecourt, Anne-Catherine; Hoebeke, Johan; Hofbauer, Karl G

    2007-06-01

    Functionally active antibodies (Abs) against central G-protein-coupled receptors have not yet been reported. We selected the hypothalamic melanocortin-4 receptor (MC4-R) as a target because of its crucial role in the regulation of energy homeostasis. A 15 amino acid sequence of the N-terminal (NT) domain was used as an antigen. This peptide showed functional activity in surface plasmon resonance experiments and in studies on HEK-293 cells overexpressing the human MC4-R (hMC4-R). Rats immunized against the NT peptide produced specific antibodies, which were purified and characterized in vitro. In HEK-293 cells, rat anti-NT Abs showed specific immunofluorescence labeling of hMC4-R. They reduced the production of cAMP under basal conditions and after stimulation with a synthetic MC4-R agonist. Rats immunized against the NT peptide developed a phenotype consistent with MC4-R blockade, that is, increased food intake and body weight, increased liver and fat pad weight, and elevated plasma triglycerides. In a separate experiment in rats, an increase in food intake could be produced after injection of purified Abs into the third ventricle. Similar results were obtained in rats injected with anti-NT Abs raised in rabbits. Our data show for the first time that active immunization of rats against the NT sequence of the MC4-R results in specific Abs, which appear to stimulate food intake by acting as inverse agonists in the hypothalamus.

  7. Small-molecule Wnt agonists correct cleft palates in Pax9 mutant mice in utero.

    Science.gov (United States)

    Jia, Shihai; Zhou, Jing; Fanelli, Christopher; Wee, Yinshen; Bonds, John; Schneider, Pascal; Mues, Gabriele; D'Souza, Rena N

    2017-10-15

    Clefts of the palate and/or lip are among the most common human craniofacial malformations and involve multiple genetic and environmental factors. Defects can only be corrected surgically and require complex life-long treatments. Our studies utilized the well-characterized Pax9 -/- mouse model with a consistent cleft palate phenotype to test small-molecule Wnt agonist therapies. We show that the absence of Pax9 alters the expression of Wnt pathway genes including Dkk1 and Dkk2 , proven antagonists of Wnt signaling. The functional interactions between Pax9 and Dkk1 are shown by the genetic rescue of secondary palate clefts in Pax9 -/- Dkk1 f/+ ;Wnt1Cre embryos. The controlled intravenous delivery of small-molecule Wnt agonists (Dkk inhibitors) into pregnant Pax9 +/- mice restored Wnt signaling and led to the growth and fusion of palatal shelves, as marked by an increase in cell proliferation and osteogenesis in utero , while other organ defects were not corrected. This work underscores the importance of Pax9-dependent Wnt signaling in palatogenesis and suggests that this functional upstream molecular relationship can be exploited for the development of therapies for human cleft palates that arise from single-gene disorders. © 2017. Published by The Company of Biologists Ltd.

  8. Dopamine agonists and delusional jealousy in Parkinson's disease: a cross-sectional prevalence study.

    Science.gov (United States)

    Poletti, Michele; Perugi, Giulio; Logi, Chiara; Romano, Anna; Del Dotto, Paolo; Ceravolo, Roberto; Rossi, Giuseppe; Pepe, Pasquale; Dell'Osso, Liliana; Bonuccelli, Ubaldo

    2012-11-01

    Delusional jealousy (DJ) has been described in patients with Parkinson's disease (PD) on dopaminergic therapy, but a role for dopaminergic therapy in DJ has not been established. The current cross-sectional study on DJ investigated its association with dopaminergic therapies compared with their associations with hallucinations and its prevalence in PD patients. Eight hundred five consecutive patients with PD were enrolled between January 2009 and June 2010. DJ was identified in 20 patients (2.48%) and hallucinations in 193 patients (23.98%). In the multivariate logistic regression analyses, dopamine agonists were significantly associated with DJ (odds ratio, 18.1; 95% CI, 3.0-infinity; P = .0002) but not with hallucinations (odds ratio, 0.73; 95% CI, 0.49-1.10; P = .133). These findings suggest that dopamine agonist treatment represents a risk factor for DJ in PD independent of the presence of a dementing disorder, and the presence of this additional nonmotor side effect should be investigated in this clinical population. Copyright © 2012 Movement Disorder Society.

  9. Role and development of GLP-1 receptor agonists in the management of diabetes

    Directory of Open Access Journals (Sweden)

    Chee W Chia

    2009-05-01

    Full Text Available Chee W Chia, Josephine M EganNational Institutes of Health, National Institute on Aging, Intramural Research Program, Baltimore, Maryland, USAAbstract: Glucagon-like peptide-1 (GLP-1 is a hormone secreted from enteroendocrine L cells of the intestine in response to food. Exogenous GLP-1 administration at pharmacological doses results in many effects that are beneficial for treating type 2 diabetes, these include: (1 an increase in insulin secretion from β cells; (2 a suppression of glucagon secretion from α cells in the presence of hyperglycemia but not hypoglycemia; (3 a delay in gastric emptying and gut motility which in turns delays absorption of ingested nutrients and dampens post-prandial glucose excursion; and (4 an increase in the duration of postprandial satiety therefore suppressing appetite and decreasing food intake which eventually leads to weight loss. However, GLP-1 is subject to rapid enzymatic degradation, and therefore, not suitable for long-term treatment. A synthetic enzyme-resistant GLP-1 receptor agonist that reproduces the biological effects of GLP-1 is in use and more are under development. This review aims at providing a summary of the properties of GLP-1 and the development of GLP-1-based therapies for treatment of diabetes.Keywords: incretin, GLP-1, GLP-1R agonist, diabetes

  10. Examining the safety of PPAR agonists - current trends and future prospects.

    Science.gov (United States)

    Bortolini, Michele; Wright, Matthew B; Bopst, Martin; Balas, Bogdana

    2013-01-01

    The peroxisome proliferator-activated receptor (PPAR)-α and -γ agonists, fibrates and glitazones, are effective treatments for dyslipidemia and type 2 diabetes mellitus, respectively, but exhibit class-related, as well as compound-specific safety characteristics. This article reviews the profiles of PPAR-α, PPAR-γ, and dual PPAR-α/γ agonists with regard to class-related and compound-specific efficacy and adverse effects. We explore how learnings from first-generation drugs are being applied to develop safer PPAR-targeted therapies. The finding that rosiglitazone may increase risk for cardiovascular events has led to regulatory guidelines requiring demonstration of cardiovascular safety in appropriate outcome trials for new type 2 diabetes mellitus drugs. The emerging data on the possibly increased risk of bladder cancer with pioglitazone may prompt the need for post-approval safety studies for new drugs. Since PPAR-α and -γ affect key cardiometabolic risk factors (diabetic dyslipidemia, insulin resistance, hyperglycemia, and inflammation) in a complementary fashion, combining their benefits has emerged as a particularly attractive option. New PPAR-targeted therapies that balance the relative potency and/or activity toward PPAR-α and -γ have shown promise in retaining efficacy while reducing potential side effects.

  11. Proton pump inhibitor Lansoprazole is a nuclear Liver X Receptor agonist

    Science.gov (United States)

    Cronican, Andrea A.; Fitz, Nicholas F.; Pham, Tam; Fogg, Allison; Kifer, Brionna; Koldamova, Radosveta; Lefterov, Iliya

    2010-01-01

    The liver X receptors (LXRα and LXRβ) are transcription factors that control the expression of genes primarily involved in cholesterol metabolism. In brain, in addition to normal neuronal function, cholesterol metabolism is important for APP proteolytic cleavage, secretase activities, Aβ aggregation and clearance. Particularly significant in this respect is the LXR mediated transcriptional control of APOE, which is the only proven risk factor for late onset Alzheimer’s disease. Using a transactivation reporter assay for screening pharmacologically active compounds and off patent drugs we identified the Proton Pump Inhibitor Lansoprazole as an LXR agonist. In secondary screens and counter-screening assays, it was confirmed that Lansoprazole directly activates LXR, increases the expression of LXR target genes in brain-derived human cell lines, and increases Abca1 and Apo-E protein levels in primary astrocytes derived from wild type but not LXRα/β double knockout mice. Other PPIs activate LXR as well, but the efficiency of activation depends on their structural similarities to Lansoprazole. The identification of widely used, drug with LXR agonist-like activity opens the possibility for systematic preclinical testing in at least two diseases – Alzheimer’s disease and atherosclerosis. PMID:20060385

  12. Novel retinoic acid receptor alpha agonists for treatment of kidney disease.

    Directory of Open Access Journals (Sweden)

    Yifei Zhong

    Full Text Available Development of pharmacologic agents that protect podocytes from injury is a critical strategy for the treatment of kidney glomerular diseases. Retinoic acid reduces proteinuria and glomerulosclerosis in multiple animal models of kidney diseases. However, clinical studies are limited because of significant side effects of retinoic acid. Animal studies suggest that all trans retinoic acid (ATRA attenuates proteinuria by protecting podocytes from injury. The physiological actions of ATRA are mediated by binding to all three isoforms of the nuclear retinoic acid receptors (RARs: RARα, RARβ, and RARγ. We have previously shown that ATRA exerts its renal protective effects mainly through the agonism of RARα. Here, we designed and synthesized a novel boron-containing derivative of the RARα-specific agonist Am580. This new derivative, BD4, binds to RARα receptor specifically and is predicted to have less toxicity based on its structure. We confirmed experimentally that BD4 binds to RARα with a higher affinity and exhibits less cellular toxicity than Am580 and ATRA. BD4 induces the expression of podocyte differentiation markers (synaptopodin, nephrin, and WT-1 in cultured podocytes. Finally, we confirmed that BD4 reduces proteinuria and improves kidney injury in HIV-1 transgenic mice, a model for HIV-associated nephropathy (HIVAN. Mice treated with BD4 did not develop any obvious toxicity or side effect. Our data suggest that BD4 is a novel RARα agonist, which could be used as a potential therapy for patients with kidney disease such as HIVAN.

  13. Functional human antibody CDR fusions as long-acting therapeutic endocrine agonists.

    Science.gov (United States)

    Liu, Tao; Zhang, Yong; Liu, Yan; Wang, Ying; Jia, Haiqun; Kang, Mingchao; Luo, Xiaozhou; Caballero, Dawna; Gonzalez, Jose; Sherwood, Lance; Nunez, Vanessa; Wang, Danling; Woods, Ashley; Schultz, Peter G; Wang, Feng

    2015-02-03

    On the basis of the 3D structure of a bovine antibody with a well-folded, ultralong complementarity-determining region (CDR), we have developed a versatile approach for generating human or humanized antibody agonists with excellent pharmacological properties. Using human growth hormone (hGH) and human leptin (hLeptin) as model proteins, we have demonstrated that functional human antibody CDR fusions can be efficiently engineered by grafting the native hormones into different CDRs of the humanized antibody Herceptin. The resulting Herceptin CDR fusion proteins were expressed in good yields in mammalian cells and retain comparable in vitro biological activity to the native hormones. Pharmacological studies in rodents indicated a 20- to 100-fold increase in plasma circulating half-life for these antibody agonists and significantly extended in vivo activities in the GH-deficient rat model and leptin-deficient obese mouse model for the hGH and hLeptin antibody fusions, respectively. These results illustrate the utility of antibody CDR fusions as a general and versatile strategy for generating long-acting protein therapeutics.

  14. Profound and Rapid Reduction in Body Temperature Induced by the Melanocortin Receptor Agonists

    Science.gov (United States)

    Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

    2014-01-01

    The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5′AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII’s effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature. PMID:25065745

  15. Agonistic activity of tamoxifen, a selective estrogen-receptor modulator (SERM), on arthritic ovariectomized mice

    Science.gov (United States)

    Silva, L.A.S.; Felix, F.B.; Araujo, J.M.D.; Souza, E.V.; Camargo, E.A.; Grespan, R.

    2017-01-01

    Arthritis is positively associated with the decline of sex hormones, especially estrogen. Tamoxifen (TMX) is a selective estrogen receptor modulator, possessing agonist or antagonistic activity in different tissues. Thus, the objective of this study was to investigate the effect of TMX on the zymosan-induced arthritis model. Female Swiss normal and ovariectomized (OVX) mice were divided into groups and treated for five days with TMX (0.3, 0.9 or 2.7 mg/kg) or 17-β-estradiol (E2, 50 µg/kg). On the fifth day, arthritis was induced and 4 h later, leukocyte migration into joint cavities was evaluated. The neutrophil migration in OVX animals, but not in normal mice, treated with TMX (all tested doses) was significantly decreased compared with mice that received the vehicle (P≤0.05). Similarly, this effect was also demonstrated in the E2-treated group. Therefore, the present study demonstrates that TMX presented agonist effects in inhibiting neutrophil migration and preventing arthritis progression in OVX mice. PMID:29160416

  16. Agonist of inward rectifier K+ channels enhances the protection of ischemic postconditioning in isolated rat hearts.

    Science.gov (United States)

    Liao, Z; Feng, Z; Long, C

    2014-07-01

    Selective inhibition of inward rectifier K + channels could abolish the protection mediated by ischemic preconditioning, but the roles of these channels in ischemic postconditioning have not been well characterized. Our study aims to evaluate the effect of inward rectifier K + channels on the protection induced by ischemic postconditioning. Langendorff-perfused rat hearts (n=8 per group) were split into four groups: postconditioning hearts (IPO group); ischemic postconditioning with BaCl 2 hearts (PB group); ischemic postconditioning with zacopride hearts (PZ group); and without ischemic postconditioning (CON group). After suffering 30 minutes of global ischemia, groups IPO, PB and PZ went through 10 seconds of ischemic postconditioning with three different perfusates: respectively, Krebs-Henseleit buffer (IPO group); 20 μmol/L BaCl 2 (antagonist of the channel, PB group); 1 μmol/L zacopride (agonist of the channel, PZ group). At the end of reperfusion, the myocardial performance was better preserved in the PZ group than the other three groups. The PB group showed no significant differences from the CON group. Our study has shown that the I K1 channel agonist zacopride is associated with the enhancement of ischemic postconditioning. © The Author(s) 2014.

  17. Agonistic behaviour in juvenile southern rock lobster, Jasus edwardsii (Decapoda, Palinuridae: implications for developing aquaculture

    Directory of Open Access Journals (Sweden)

    Chris Carter

    2014-11-01

    Full Text Available The Southern rock lobster, Jasus edwardsii, is a temperate species of spiny lobster with established well managed fisheries in Australia and New Zealand. It has also been under consideration as a species with aquaculture potential. Agonistic behaviour has important consequences under aquaculture conditions that encompass direct effects, such as damage or death of protagonists, and indirect effects on growth that relate to resource access, principally food and refuge. This study aimed to identify and characterize behaviours and to make a preliminary investigation of their occurrence under tank culture. Juvenile Jasus edwardsii were examined in a flow-through seawater system using a remote video camera system. Twenty-nine behaviours were divided into three sub-groups: aggressive (11, avoidance (6 and others (12. Aggressive behaviours included attacks, pushing, lifting, clasping and carrying an opponent. Avoidance behaviours included moving away in a backwards-, forwards- or side-stepping motion as well as with more vigorous tail flips. These behaviours were components of twelve behavioural groups that described contact, attack and displacement between individuals. Activity was crepuscular with two clear peaks, one in the morning and the other in the evening. The occurrence of behavioural groups was not different between the morning and evening. The frequency of aggressive behaviours was not affected by changes made to stocking density or access to food. The implications of agonistic behaviours are discussed further in relation to developing aquaculture.

  18. Synthesis and SAR studies of benzyl ether derivatives as potent orally active S1P₁ agonists.

    Science.gov (United States)

    Tsuji, Takashi; Suzuki, Keisuke; Nakamura, Tsuyoshi; Goto, Taiji; Sekiguchi, Yukiko; Ikeda, Takuya; Fukuda, Takeshi; Takemoto, Toshiyasu; Mizuno, Yumiko; Kimura, Takako; Kawase, Yumi; Nara, Futoshi; Kagari, Takashi; Shimozato, Takaichi; Yahara, Chizuko; Inaba, Shinichi; Honda, Tomohiro; Izumi, Takashi; Tamura, Masakazu; Nishi, Takahide

    2014-08-01

    We report herein the synthesis and structure-activity relationships (SAR) of a series of benzyl ether compounds as an S1P₁ receptor modulator. From our SAR studies, the installation of substituents onto the central benzene ring of 2a was revealed to potently influence the S1P₁ and S1P₃ agonistic activities, in particular, an ethyl group on the 2-position afforded satisfactory S1P₁/S1P₃ selectivity. These changes of the S1P₁ and S1P₃ agonistic activities caused by the alteration of substituents on the 2-position were reasonably explained by a docking study using an S1P₁ X-ray crystal structure and S1P₃ homology modeling. We found that compounds 2b and 2e had a potent in vivo immunosuppressive efficacy along with acceptable S1P₁/S1P₃ selectivity, and confirmed that these compounds had less in vivo bradycardia risk through the evaluation of heart rate change after oral administration of the compounds (30 mg/kg, p.o.) in rats. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. Therapeutic potential of α7 nicotinic receptor agonists to regulate neuroinflammation in neurodegenerative diseases

    Directory of Open Access Journals (Sweden)

    Laura Foucault-Fruchard

    2017-01-01

    Full Text Available Neurodegenerative diseases, such as Alzheimer's, Parkinson's and Huntington's diseases, are all characterized by a component of innate immunity called neuroinflammation. Neuronal loss and neuroinflammation are two phenomena closely linked. Hence, the neuroinflammation is a relevant target for the management of the neurodegenerative diseases given that, to date, there is no treatment to stop neuronal loss. Several studies have investigated the potential effects of activators of alpha 7 nicotinic acetylcholine receptors in animal models of neurodegenerative diseases. These receptors are widely distributed in the central nervous system. After activation, they seem to mediate the cholinergic anti-inflammatory pathway in the brain. This anti-inflammatory pathway, first described in periphery, regulates activation of microglial cells considered as the resident macrophage population of the central nervous system. In this article, we shortly review the agonists of the alpha 7 nicotinic acetylcholine receptors that have been evaluated in vivo and we focused on the selective positive allosteric modulators of these receptors. These compounds represent a key element to enhance receptor activity only in the presence of the endogenous agonist.

  20. Effect of alpha 2-adrenoceptor agonists on gastric pepsin and acid secretion in the rat.

    Science.gov (United States)

    Tazi-Saad, K.; Chariot, J.; Del Tacca, M.; Rozé, C.

    1992-01-01

    1. The purpose of the present study was to analyze the effects of the alpha 2-adrenoceptor agonists clonidine, guanabenz, detomidine and medetomidine on pepsin secretion in conscious rats provided with gastric chronic fistula and to compare this with acid secretion. 2. Basal interdigestive gastric secretion, which is mainly neurally driven in the rat, and the secretion directly stimulated by the two main stimulants of chief cells, cholecystokinin octapeptide (CCK8) and methacholine, were studied. 3. Basal secretion of pepsin and acid was inhibited by all four drugs with comparable EC50S. 4. CCK-stimulated pepsin and acid secretion was less sensitive than basal pepsin and acid secretion to alpha 2-adrenoceptor inhibition. 5. Methacholine-stimulated pepsin and acid secretion was not changed by clonidine and guanabenz; methacholine-stimulated acid was even marginally increased by clonidine. 6. These results do not favour the presence of alpha 2-receptors on chief cells in the rat stomach. They rather suggest that pepsin inhibition by alpha 2-adrenoceptor agonists is indirect and due to central or peripheral inhibition of the discharge of nerve fibres activating pepsin secretion. PMID:1356566

  1. Inverse agonist and neutral antagonist actions of synthetic compounds at an insect 5-HT1 receptor.

    Science.gov (United States)

    Troppmann, B; Balfanz, S; Baumann, A; Blenau, W

    2010-04-01

    5-Hydroxytryptamine (5-HT) has been shown to control and modulate many physiological and behavioural functions in insects. In this study, we report the cloning and pharmacological properties of a 5-HT(1) receptor of an insect model for neurobiology, physiology and pharmacology. A cDNA encoding for the Periplaneta americana 5-HT(1) receptor was amplified from brain cDNA. The receptor was stably expressed in HEK 293 cells, and the functional and pharmacological properties were determined in cAMP assays. Receptor distribution was investigated by RT-PCR and by immunocytochemistry using an affinity-purified polyclonal antiserum. The P. americana 5-HT(1) receptor (Pea5-HT(1)) shares pronounced sequence and functional similarity with mammalian 5-HT(1) receptors. Activation with 5-HT reduced adenylyl cyclase activity in a dose-dependent manner. Pea5-HT(1) was expressed as a constitutively active receptor with methiothepin acting as a neutral antagonist, and WAY 100635 as an inverse agonist. Receptor mRNA was present in various tissues including brain, salivary glands and midgut. Receptor-specific antibodies showed that the native protein was expressed in a glycosylated form in membrane samples of brain and salivary glands. This study marks the first pharmacological identification of an inverse agonist and a neutral antagonist at an insect 5-HT(1) receptor. The results presented here should facilitate further analyses of 5-HT(1) receptors in mediating central and peripheral effects of 5-HT in insects.

  2. Effects of PPARγ Agonist Pioglitazone on Redox-Sensitive Cellular Signaling in Young Spontaneously Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Ima Dovinová

    2013-01-01

    Full Text Available PPARγ receptor plays an important role in oxidative stress response. Its agonists can influence vascular contractility in experimental hypertension. Our study was focused on the effects of a PPARγ agonist pioglitazone (PIO on blood pressure regulation, vasoactivity of vessels, and redox-sensitive signaling at the central (brainstem, BS and peripheral (left ventricle, LV levels in young prehypertensive rats. 5-week-old SHR were treated either with PIO (10 mg/kg/day, 2 weeks or with saline using gastric gavage. Administration of PIO significantly slowed down blood pressure increase and improved lipid profile and aortic relaxation after insulin stimulation. A significant increase in PPARγ expression was found only in BS, not in LV. PIO treatment did not influence NOS changes, but had tissue-dependent effect on SOD regulation and increased SOD activity, observed in LV. The treatment with PIO differentially affected also the levels of other intracellular signaling components: Akt kinase increased in the the BS, while β-catenin level was down-regulated in the BS and up-regulated in the LV. We found that the lowering of blood pressure in young SHR can be connected with insulin sensitivity of vessels and that β-catenin and SOD levels are important agents mediating PIO effects in the BS and LV.

  3. GLP-1 receptor agonists in the treatment of polycystic ovary syndrome.

    Science.gov (United States)

    Lamos, Elizabeth Mary; Malek, Rana; Davis, Stephen N

    2017-04-01

    Polycystic ovarian syndrome (PCOS) affects many women of child-bearing age and is characterized by hyperandrogenism, ovulatory and metabolic dysfunction. A primary treatment goal is weight reduction. The weight loss effects of glucagon-like peptide-1 receptor agonists (GLP-1RA), previously demonstrated in diabetic and obese non-diabetic patients, offer a unique opportunity to expand the medical options available to PCOS patients. Areas covered: Available clinical trials of glucagon-like peptide-1 receptor agonist therapy in PCOS were reviewed. Literature was searched from PubMed using appropriate search terms up to November 2016. Expert commentary: The available studies of GLP-1 RA therapy in the treatment of excess body weight in women with PCOS demonstrate that exenatide and liraglutide are effective in weight reduction either as monotherapy or in combination with metformin. A few studies showed that androgens may be modestly decreased and menstrual frequency may be increased. Eating behavior may be improved with liraglutide therapy. Glucose parameters are generally improved. GLP-1RAs were well-tolerated, with nausea being the most significant adverse side effect. Barriers to utilization may be the short duration studies, lack of familiarity of the medication, the route of administration (injection) and the variable outcomes on ovulation and hyperandrogenism.

  4. Palovarotene, a novel retinoic acid receptor gamma agonist for the treatment of emphysema.

    Science.gov (United States)

    Hind, Matthew; Stinchcombe, Sian

    2009-11-01

    Emphysema is characterized by the destruction of alveoli and alveolar ducts within the lungs. Retinoid signaling is believed to play a role in alveologenesis, with the retinoic acid receptor gamma thought to be required for alveolar formation. Based on this hypothesis, Roche Holding AG is developing palovarotene (R-667, RO-3300074), a selective retinoic acid receptor gamma agonist for the treatment of emphysema. In small animal studies, palovarotene was claimed to reverse the structural, functional and inflammatory features of cigarette smoke-induced emphysema. Phase I clinical trials of palovarotene in patients with emphysema demonstrated that the drug is well tolerated, with improvements observed in markers of emphysema progression. Unlike all-trans retinoic acid, the pharmacokinetic profile of palovarotene appears to be dose-proportional. At the time of publication, a phase II, placebo-controlled trial was ongoing, and was expected to report prospective measurements of exercise, gas transfer and lung densitometry endpoints. The development of a selective retinoic acid receptor gamma agonist for the treatment of emphysema represents the first of a new class of small-molecule regenerative therapies that may prove useful for the treatment of destructive or age-related lung disease.

  5. Agonistic reciprocity is associated with reduced male reproductive success within haremic social networks

    Science.gov (United States)

    Solomon-Lane, Tessa K.; Pradhan, Devaleena S.; Willis, Madelyne C.; Grober, Matthew S.

    2015-01-01

    While individual variation in social behaviour is ubiquitous and causes social groups to differ in structure, how these structural differences affect fitness remains largely unknown. We used social network analysis of replicate bluebanded goby (Lythrypnus dalli) harems to identify the reproductive correlates of social network structure. In stable groups, we quantified agonistic behaviour, reproduction and steroid hormones, which can both affect and respond to social/reproductive cues. We identified distinct, optimal social structures associated with different reproductive measures. Male hatching success (HS) was negatively associated with agonistic reciprocity, a network structure that describes whether subordinates ‘reciprocated’ agonism received from dominants. Egg laying was associated with the individual network positions of the male and dominant female. Thus, males face a trade-off between promoting structures that facilitate egg laying versus HS. Whether this reproductive conflict is avoidable remains to be determined. We also identified different social and/or reproductive roles for 11-ketotestosterone, 17β-oestradiol and cortisol, suggesting that specific neuroendocrine mechanisms may underlie connections between network structure and fitness. This is one of the first investigations of the reproductive and neuroendocrine correlates of social behaviour and network structure in replicate, naturalistic social groups and supports network structure as an important target for natural selection. PMID:26156769

  6. In vivo and in vitro studies on a muscarinic presynaptic antagonist and postsynaptic agonist: BM-5

    International Nuclear Information System (INIS)

    Nordstrom, O.; Bartafi, T.; Frieder, B.; Grimm, V.; Ladinsky, H.; Unden, A.

    1986-01-01

    This paper reports on in vitro and in vivo studies with compound BM-5 which, at proper dosage, could have great potential since it could enhance cholinergic transmission by being a presynaptic antagonist and postsynaptic agonist. Binding studies are described in which tritium-4-NMPB, a muscarinic antagonist, was displaced by compound BM-5 in membranes from striatum, cerebral cortex, cerebellum and hippocampus. The binding data are summarized, which for each brain area involved 86-92 data points evaluated by means of nonlinear regression methods. Compound BM-5 recognized in each brain region a population of high and a population of low affinity binding sites; both of which were labelled with tritium-4-NMPB. It is shown that compound BM-5 causes muscarinic cholinergic agonist-like effects such as redness of the eye, increased motility in the gut, and impairment of locomotor behavior. It also produces muscarinic super-sensitivity upon chronic treatment, and decreases rat striatial ACh content by acute treatment

  7. PPARγ Agonists in Adaptive Immunity: What Do Immune Disorders and Their Models Have to Tell Us?

    Directory of Open Access Journals (Sweden)

    Laurindo Ferreira da Rocha Junior

    2013-01-01

    Full Text Available Adaptive immunity has evolved as a very powerful and highly specialized tool of host defense. Its classical protagonists are lymphocytes of the T- and B-cell lineage. Cytokines and chemokines play a key role as effector mechanisms of the adaptive immunity. Some autoimmune and inflammatory diseases are caused by disturbance of the adaptive immune system. Recent advances in understanding the pathogenesis of autoimmune diseases have led to research on new molecular and therapeutic targets. PPARγ are members of the nuclear receptor superfamily and are transcription factors involved in lipid metabolism as well as innate and adaptive immunity. PPARγ is activated by synthetic and endogenous ligands. Previous studies have shown that PPAR agonists regulate T-cell survival, activation and T helper cell differentiation into effector subsets: Th1, Th2, Th17, and Tregs. PPARγ has also been associated with B cells. The present review addresses these issues by placing PPARγ agonists in the context of adaptive immune responses and the relation of the activation of these receptors with the expression of cytokines involved in adaptive immunity.

  8. Profound and rapid reduction in body temperature induced by the melanocortin receptor agonists.

    Science.gov (United States)

    Xu, Yuanzhong; Kim, Eun Ran; Fan, Shengjie; Xia, Yan; Xu, Yong; Huang, Cheng; Tong, Qingchun

    2014-08-22

    The melanocortin receptor 4 (MC4R) plays a major role in body weight regulation and its agonist MTII has been widely used to study the role of MC4Rs in energy expenditure promotion and feeding reduction. Unexpectedly, we observed that intraperitoneal (i.p.) administration of MTII induced a rapid reduction in both body temperature and energy expenditure, which was independent of its effect on feeding and followed by a prolonged increase in energy expenditure. The rapid reduction was at least partly mediated by brain neurons since intracerebroventricular (icv) administration of alpha melanocyte-stimulating hormone, an endogenous melanocortin receptor agonist, produced a similar response. In addition, the body temperature-lowering effect of MTII was independent of the presence of MC4Rs, but in a similar fashion to the previously shown effect on body temperature by 5'AMP. Moreover, β-adrenergic receptors (β-ARs) were required for the recovery from low body temperature induced by MTII and further pharmacological studies showed that the MTII's effect on body temperature may be partially mediated by the vasopressin V1a receptors. Collectively, our results reveal a previously unappreciated role for the melanocortin pathway in rapidly lowering body temperature. Copyright © 2014 Elsevier Inc. All rights reserved.

  9. Blockade of alcohol's amnestic activity in humans by an alpha5 subtype benzodiazepine receptor inverse agonist.

    Science.gov (United States)

    Nutt, David J; Besson, Marie; Wilson, Susan J; Dawson, Gerard R; Lingford-Hughes, Anne R

    2007-12-01

    Alcohol produces many subjective and objective effects in man including pleasure, sedation, anxiolysis, plus impaired eye movements and memory. In human volunteers we have used a newly available GABA-A/benzodiazepine receptor inverse agonist that is selective for the alpha5 subtype (a5IA) to evaluate the role of this subtype in mediating these effects of alcohol on the brain. After pre-treatment with a5IA, we found almost complete blockade of the marked impairment caused by alcohol (mean breath concentration 150mg/100ml) of word list learning and partial but non-significant reversal of subjective sedation without effects on other measures such as intoxication, liking, and slowing of eye movements. This action was not due to alterations in alcohol kinetics and so provides the first proof of concept that selectively decreasing GABA-A receptor function at a specific receptor subtype can offset some actions of alcohol in humans. It also supports growing evidence for a key role of the alpha5 subtype in memory. Inverse agonists at other GABA-A receptor subtypes may prove able to reverse other actions of alcohol, and so offer a new approach to understanding the actions of alcohol in the human brain and in the treatment of alcohol related disorders in humans.

  10. Vitamin D Receptor Agonists Target CXCL10: New Therapeutic Tools for Resolution of Inflammation

    Directory of Open Access Journals (Sweden)

    Sabino Scolletta

    2013-01-01

    Full Text Available Understanding the many biological extraskeletal actions of vitamin D has increased in the past decades. Indeed, vitamin D and analogue molecules, besides the classical actions on bone metabolism, exert several beneficial effects on metabolic homeostasis, heart-cardiovascular, brain, and muscle physiological functions, throughout the interaction with the specific vitamin D receptor (VDR. In particular, VDR agonists powerfully control innate and adaptive immune system with favorable effects on human health. VDR ligands act as immunomodulators that are potent enough to retain anti-inflammatory effects, even though the mechanism underlying those effects is not yet fully elucidated. VDR agonists exert a significant suppression of inflammatory processes switching the immune response from T helper 1 (Th1 to T helper 2 (Th2 dominance and counteracting the self-enhancing inflammatory loop between immune and resident cells, especially by cytokine release impairment. Those molecules are able, indeed, to reduce the release of the interferon (IFN-induced 10 kDa protein IP-10/CXCL10, a powerful chemokine driving Th1-mediated inflammation. Based on their features, VDR ligands show the potentiality to be included in immunosuppressive regimens, aimed to control auto- and alloimmune Th1-driven overreactivity, occurring, for example, in autoimmune disease or graft rejection.

  11. GPR119 agonists: a promising approach for T2DM treatment? A SWOT analysis of GPR119.

    Science.gov (United States)

    Kang, Sang-Uk

    2013-12-01

    Ever since its advent as a promising therapeutic target for type 2 diabetes mellitus (T2DM), G-protein-coupled receptor 119 (GPR119) has received much interest from the pharmaceutical industry. This interest peaked in June 2010, when Sanofi-Aventis agreed to pay Metabolex (Cymabay Therapeutics) US$375 million for MBX-2982, which was a representative orally active GPR119 agonist. However, Sanofi-Aventis opted to terminate the deal in May 2011 and another leading GPR119 agonist, GSK1292263, had a loss of efficacy during its clinical trial. In this review, I discuss the pros and cons of GPR119 through a strengths, weaknesses, opportunities, and threats (SWOT) analysis and propose development strategies for the eventual success of a GPR119 agonist development program. Copyright © 2013 Elsevier Ltd. All rights reserved.

  12. Ghrelin receptor inverse agonists: identification of an active peptide core and its interaction epitopes on the receptor

    DEFF Research Database (Denmark)

    Holst, Birgitte; Lang, Manja; Brandt, Erik

    2006-01-01

    [D-Arg1,D-Phe5,D-Trp7,9,Leu11]Substance P functions as a low-potency antagonist but a high-potency full inverse agonist on the ghrelin receptor. Through a systematic deletion and substitution analysis of this peptide, the C-terminal carboxyamidated pentapeptide wFwLX was identified as the core...... structure, which itself displayed relatively low inverse agonist potency. Mutational analysis at 17 selected positions in the main ligand-binding crevice of the ghrelin receptor demonstrated that ghrelin apparently interacts only with residues in the middle part of the pocket [i.e., between transmembrane...... upon both AspII:20 and GluIII:09. The identified pharmacophore can possibly serve as the basis for targeted discovery of also nonpeptide inverse agonists for the ghrelin receptor....

  13. A DFT approach to discriminate the antagonist and partial agonist activity of ligands binding to the NMDA receptor

    Science.gov (United States)

    Haslak, Zeynep Pinar; Bozkurt, Esra; Dutagaci, Bercem; De Proft, Frank; Aviyente, Viktorya; De Vleeschouwer, Freija

    2018-02-01

    The activation of N-methyl-D-aspartate receptors is found to be intimately associated with neurodegenerative diseases which make them promising therapeutic targets. Despite the significantly increasing multidisciplinary interests centred on this ionotropic channel, design of new ligands with intended functional activity remains a great challenge. In this article, a computational study based on density functional theory is presented to understand the structural factors of ligands determining their function as antagonists and partial agonists. With this aim, the GluN1 subunit is chosen as being one of the essential components in the activation mechanism, and quantum chemical calculations are implemented for 30 antagonists and 30 partial agonists known to bind to this subunit with different binding affinities. Several quantum chemical descriptors are investigated which might unlock the difference between antagonists and partial agonists.

  14. STING agonists enable antiviral cross-talk between human cells and confer protection against genital herpes in mice

    DEFF Research Database (Denmark)

    Skouboe, Morten K; Knudsen, Alice; Reinert, Line S

    2018-01-01

    In recent years, there has been an increasing interest in immunomodulatory therapy as a means to treat various conditions, including infectious diseases. For instance, Toll-like receptor (TLR) agonists have been evaluated for treatment of genital herpes. However, although the TLR7 agonist imiquimod...... herpes simplex virus (HSV) 2 replication and improved the clinical outcome of infection. More importantly, local application of CDNs at the genital epithelial surface gave rise to local IFN activity, but only limited systemic responses, and this treatment conferred total protection against disease...... to TLRs, STING is expressed broadly, including in epithelial cells. Here we report that natural and non-natural STING agonists strongly induce type I IFNs in human cells and in mice in vivo, without stimulating significant inflammatory gene expression. Systemic treatment with 2'3'-cGAMP reduced genital...

  15. Effects of the PPARγ agonist troglitazone on endothelial cells in vivo and in vitro: Differences between human and mouse

    International Nuclear Information System (INIS)

    Kakiuchi-Kiyota, Satoko; Vetro, Joseph A.; Suzuki, Shugo; Varney, Michelle L.; Han, Huai-Yun; Nascimento, Merielen; Pennington, Karen L.; Arnold, Lora L.; Singh, Rakesh K.; Cohen, Samuel M.

    2009-01-01

    Peroxisome proliferator-activated receptor gamma (PPARγ) agonists and PPARγ/α dual agonists have been or are being developed for clinical use in the treatment of type 2 diabetes mellitus and hyperlipidemias. A common tumor finding in rodent carcinogenicity studies for these agonists is hemangioma/hemangiosarcoma in mice but not in rats. We hypothesized that increased endothelial cell proliferation may be involved in the mechanism of PPAR agonist-induced vascular tumors in mice, and we investigated the effects on endothelial cells utilizing troglitazone, the first clinically used PPARγ agonist, in vivo and in vitro. Troglitazone (400 and 800 mg/kg/day) induced hemangiosarcomas in mice in a 2-year bioassay. We showed that troglitazone increased endothelial cell proliferation in brown and white adipose tissue and liver in mice at sarcomagenic doses after 4 weeks of treatment. Troglitazone was cytotoxic both to human dermal microvascular endothelial cells (HMEC1) and mouse mammary fat pad microvascular endothelial cells (MFP MVEC) at high concentrations. However, MFP MVEC were more resistant to the cytotoxic effects of troglitazone based on the much lower LC 50 in HMEC1 (17.4 μM) compared to MFP MVEC (92.2 μM). Troglitazone increased the proliferation and survival of MFP MVEC but not HMEC1 in growth factor reduced conditions. Our data demonstrate that troglitazone may induce hemangiosarcomas in mice, at least in part, through enhancement of survival and proliferation of microvascular endothelial cells. Such an effect does not occur with human cells, suggesting that human may react differently to exposure to PPAR agonists compared with mice.

  16. Endogenous stem cell proliferation induced by intravenous hedgehog agonist administration after contusion in the adult rat spinal cord.

    Science.gov (United States)

    Bambakidis, Nicholas C; Horn, Eric M; Nakaji, Peter; Theodore, Nicholas; Bless, Elizabeth; Dellovade, Tammy; Ma, Chiyuan; Wang, Xukui; Preul, Mark C; Coons, Stephen W; Spetzler, Robert F; Sonntag, Volker K H

    2009-02-01

    Sonic hedgehog (Shh) is a glycoprotein molecule that upregulates the transcription factor Gli1. The Shh protein plays a critical role in the proliferation of endogenous neural precursor cells when directly injected into the spinal cord after a spinal cord injury in adult rodents. Small-molecule agonists of the hedgehog (Hh) pathway were used in an attempt to reproduce these findings through intravenous administration. The expression of Gli1 was measured in rat spinal cord after the intravenous administration of an Hh agonist. Ten adult rats received a moderate contusion and were treated with either an Hh agonist (10 mg/kg, intravenously) or vehicle (5 rodents per group) 1 hour and 4 days after injury. The rats were killed 5 days postinjury. Tissue samples were immediately placed in fixative. Samples were immunohistochemically stained for neural precursor cells, and these cells were counted. Systemic dosing with an Hh agonist significantly upregulated Gli1 expression in the spinal cord (p < 0.005). After spinal contusion, animals treated with the Hh agonist had significantly more nestin-positive neural precursor cells around the rim of the lesion cavity than in vehicle-treated controls (means +/- SDs, 46.9 +/- 12.9 vs 20.9 +/- 8.3 cells/hpf, respectively, p < 0.005). There was no significant difference in the area of white matter injury between the groups. An intravenous Hh agonist at doses that upregulate spinal cord Gli1 transcription also increases the population of neural precursor cells after spinal cord injury in adult rats. These data support previous findings based on injections of Shh protein directly into the spinal cord.

  17. Hepatocellular proliferation in response to agonists of peroxisome proliferator-activated receptor alpha: a role for kupffer cells?

    Directory of Open Access Journals (Sweden)

    Cunningham Michael

    2006-01-01

    Full Text Available Abstract Background It has been proposed that PPARα agonists stimulate Kupffer cells in rodents which in turn, release mitogenic factors leading to hepatic hyperplasia, and eventually cancer. However, Kupffer cells do not express PPARα receptors, and PPARα agonists stimulate hepatocellular proliferation in both TNFα- and TNFα receptor-null mice, casting doubt on the involvement of Kupffer cells in the mitogenic response to PPARα agonists. This study was therefore designed to investigate whether the PPARα agonist PFOA and the Kupffer cell inhibitor methylpalmitate produce opposing effects on hepatocellular proliferation and Kupffer cell activity in vivo, in a manner that would implicate these cells in the mitogenic effects of PPARα agonists. Methods Male Sprague-Dawley rats were treated intravenously via the tail vein with methylpalmitate 24 hrs prior to perfluorooctanoic acid (PFOA, and were sacrificed 24 hrs later, one hr after an intraperitoneal injection of bromodeoxyuridine (BrdU. Sera were analyzed for TNFα and IL-1β. Liver sections were stained immunohistochemically and quantified for BrdU incorporated into DNA. Results Data show that PFOA remarkably stimulated hepatocellular proliferation in the absence of significant changes in the serum levels of either TNFα or IL-1β. In addition, methylpalmitate did not alter the levels of these mitogens in PFOA-treated animals, despite the fact that it significantly blocked the hepatocellular proliferative effect of PFOA. Correlation between hepatocellular proliferation and serum levels of TNFα or IL-1β was extremely poor. Conclusion It is unlikely that mechanisms involving Kupffer cells play an eminent role in the hepatic hyperplasia, and consequently hepatocarcinogenicity attributed to PPARα agonists. This conclusion is based on the above mentioned published data and the current findings showing animals treated with PFOA alone or in combination with methylpalmitate to have similar

  18. Effects of local anesthetics on cholinergic agonist binding affinity of central nervous system. cap alpha. -bungarotoxin receptors

    Energy Technology Data Exchange (ETDEWEB)

    Lukas, R.L.; Bennett, E.L.

    1979-12-01

    In general, pharmacological effects of local anesthetics may be attributed to their ability to reversibly block the propagation of nerve and muscle action potentials. At physiologically potent concentrations, local anesthetics (LA) also act as noncompetitive antagonists of the physiological response of post-synaptic nicotinic acetylcholine receptors (nAChR) to cholinergic agonists, and increase agonist binding affinities of nAChR from electric organ. It is postulated that the primary site of LA action on nAChR function is at the receptor-coupled ionophore. Furthermore, LA-nAChR ionophore interactions are thought to accelerate physiological desensitization of nAChR, manifest biochemically as increased affinity of nAChR for agonist. Specific receptors for ..cap alpha..-bungarotoxin (..cap alpha..-Bgt), a potent competitive antagonist at nAChR sites in the periphery, have been detected in rat central nervous system membrane preparations. The affinity of these central ..cap alpha..-Bgt receptors (..cap alpha..-BgtR) for cholinergic agonists is found to increase on exposure to agonist. Nevertheless, on the basis of inconsistent pharmacological and physiological results, uncertainty remains regarding the relationship between ..cap alpha..-BgtR and authentic nAChR in the CNS, despite a wide body of biochemical and histological evidence consistent with their identity. Reasoning that if CNS ..cap alpha..-BgtR are true in nAChR, coupled to functional ion channels, LA might be expected to cause biochemically measurable increases in ..cap alpha..-BgtR affinity for cholinergic agonists, we have undertaken a study of the effects of LA on the ability of acetylcholine (ACh) to inhibit interaction of ..cap alpha..-BgtR with /sup 3/H-labeled ..cap alpha..-Bgt.

  19. Adaptability and selectivity of human peroxisome proliferator-activated receptor (PPAR) pan agonists revealed from crystal structures

    International Nuclear Information System (INIS)

    Oyama, Takuji; Toyota, Kenji; Waku, Tsuyoshi; Hirakawa, Yuko; Nagasawa, Naoko; Kasuga, Jun-ichi; Hashimoto, Yuichi; Miyachi, Hiroyuki; Morikawa, Kosuke

    2009-01-01

    The structures of the ligand-binding domains (LBDs) of human peroxisome proliferator-activated receptors (PPARα, PPARγ and PPARδ) in complexes with a pan agonist, an α/δ dual agonist and a PPARδ-specific agonist were determined. The results explain how each ligand is recognized by the PPAR LBDs at an atomic level. Peroxisome proliferator-activated receptors (PPARs) belong to the nuclear hormone receptor family, which is defined as transcriptional factors that are activated by the binding of ligands to their ligand-binding domains (LBDs). Although the three PPAR subtypes display different tissue distribution patterns and distinct pharmacological profiles, they all are essentially related to fatty-acid and glucose metabolism. Since the PPARs share similar three-dimensional structures within the LBDs, synthetic ligands which simultaneously activate two or all of the PPARs could be potent candidates in terms of drugs for the treatment of abnormal metabolic homeostasis. The structures of several PPAR LBDs were determined in complex with synthetic ligands, derivatives of 3-(4-alkoxyphenyl)propanoic acid, which exhibit unique agonistic activities. The PPARα and PPARγ LBDs were complexed with the same pan agonist, TIPP-703, which activates all three PPARs and their crystal structures were determined. The two LBD–ligand complex structures revealed how the pan agonist is adapted to the similar, but significantly different, ligand-binding pockets of the PPARs. The structures of the PPARδ LBD in complex with an α/δ-selective ligand, TIPP-401, and with a related δ-specific ligand, TIPP-204, were also determined. The comparison between the two PPARδ complexes revealed how each ligand exhibits either a ‘dual selective’ or ‘single specific’ binding mode

  20. Effects of structural modifications of N-CPM-normorphine derivatives on agonist and antagonist activities in isolated organs.

    Science.gov (United States)

    Riba, P; Tóth, Z; Hosztafi, S; Friedmann, T; Fürst, S

    2003-01-01

    The agonistic and antagonistic properties of N-cyclopropylmethyl (N-CPM) morphine derivatives were observed in mouse vas deferens (MVD), longitudinal muscle of guinea pig ileum (GPI) and rabbit vas deferens (LVD). In MVD the K(e) values of the titled compounds (N-CPM-morphine, N-CPM-isomorphine, N-CPM-dihydromorphine, N-CPM-dihydroisomorpPhine, N-CPM-dihydromorphone and naltrexone) were measured for mu-, kappa- and delta-receptors using normorphine, ethylketocyclazocine (EKC) and D-Pen2-D-Pen5-enkephaline (DPDPE) as selective agonists on the receptors, respectively. For mu-receptors of MVD the tested compounds showed similar affinity. For kappa-receptors the non-iso-6-OH derivatives possessed much less affinity than the iso-derivatives. Similar difference could be observed for delta-receptors. The agonistic activities of these compounds in MVD were observed to be between 0-20% of the inhibition of muscle contractions. In GPI the compounds except naltrexone possessed strong agonistic activities effectively antagonized by nor-binaltorphimine (nor-BNI) (K(e) of nor-BNI was 0.23 nM) suggesting that they were strong kappa-receptor agonists. We investigated these agents in LVD too, which contains kappa-receptors, but they did not produce any agonist potencies. It raises the possibility that the kappa-receptor subtypes of LVD and MVD are different from the kappa-receptor subtype of GPI or the vasa deferentia contain much fewer kappa-receptors than GPI and the intrinsic activities of these compounds are too small to reach the 50% inhibition of the contractions.

  1. Microdose gonadotropin-releasing hormone agonist in the absence of exogenous gonadotropins is not sufficient to induce multiple follicle development.

    Science.gov (United States)

    Chung, Karine; Fogle, Robin; Bendikson, Kristin; Christenson, Kamilee; Paulson, Richard

    2011-01-01

    Because the effectiveness of the "microdose flare" stimulation protocol often is attributed to the dramatic endogenous gonadotropin release induced by the GnRH agonist, the aim of this study was to determine whether use of microdose GnRH agonist alone could induce multiple ovarian follicle development in normal responders. Based on these data, the duration of gonadotropin rise is approximately 24 to 48 hours and is too brief to sustain continued multiple follicle growth. Copyright © 2011 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  2. The GPR139 reference agonists 1a and 7c, and tryptophan and phenylalanine share a common binding site

    DEFF Research Database (Denmark)

    Shehata, Mohamed A.; Jensen, Anne Cathrine Nøhr; Jespers, Willem

    2017-01-01

    for GPR139. Two series published by Shi et al. and Dvorak et al. included agonists 1a and 7c respectively, with potencies in the ten-nanomolar range. Furthermore, Isberg et al. and Liu et al. have previously shown that tryptophan (Trp) and phenylalanine (Phe) can activate GPR139 in the hundred...... important for the activation of GPR139 as predicted by the receptor model. The initial ligand-receptor complex was optimized through free energy perturbation simulations, generating a refined GPR139 model in agreement with experimental data. In summary, the GPR139 reference surrogate agonists 1a and 7c...

  3. Muscarinic receptor agonists stimulate matrix metalloproteinase 1-dependent invasion of human colon cancer cells

    International Nuclear Information System (INIS)

    Raufman, Jean-Pierre; Cheng, Kunrong; Saxena, Neeraj; Chahdi, Ahmed; Belo, Angelica; Khurana, Sandeep; Xie, Guofeng

    2011-01-01

    Highlights: ► Muscarinic receptor agonists stimulated robust human colon cancer cell invasion. ► Anti-matrix metalloproteinase1 antibody pre-treatment blocks cell invasion. ► Bile acids stimulate MMP1 expression, cell migration and MMP1-dependent invasion. -- Abstract: Mammalian matrix metalloproteinases (MMPs) which degrade extracellular matrix facilitate colon cancer cell invasion into the bloodstream and extra-colonic tissues; in particular, MMP1 expression correlates strongly with advanced colon cancer stage, hematogenous metastasis and poor prognosis. Likewise, muscarinic receptor signaling plays an important role in colon cancer; muscarinic receptors are over-expressed in colon cancer compared to normal colon epithelial cells. Muscarinic receptor activation stimulates proliferation, migration and invasion of human colon cancer cells. In mouse intestinal neoplasia models genetic ablation of muscarinic receptors attenuates carcinogenesis. In the present work, we sought to link these observations by showing that MMP1 expression and activation plays a mechanistic role in muscarinic receptor agonist-induced colon cancer cell invasion. We show that acetylcholine, which robustly increases MMP1 expression, stimulates invasion of HT29 and H508 human colon cancer cells into human umbilical vein endothelial cell monolayers – this was abolished by pre-incubation with atropine, a non-selective muscarinic receptor inhibitor, and by pre-incubation with anti-MMP1 neutralizing antibody. Similar results were obtained using a Matrigel chamber assay and deoxycholyltaurine (DCT), an amidated dihydroxy bile acid associated with colon neoplasia in animal models and humans, and previously shown to interact functionally with muscarinic receptors. DCT treatment of human colon cancer cells resulted in time-dependent, 10-fold increased MMP1 expression, and DCT-induced cell invasion was also blocked by pre-treatment with anti-MMP1 antibody. This study contributes to understanding

  4. Muscarinic receptor agonists stimulate matrix metalloproteinase 1-dependent invasion of human colon cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Raufman, Jean-Pierre, E-mail: jraufman@medicine.umaryland.edu [Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, MD (United States); Cheng, Kunrong; Saxena, Neeraj; Chahdi, Ahmed; Belo, Angelica; Khurana, Sandeep; Xie, Guofeng [Division of Gastroenterology and Hepatology, University of Maryland School of Medicine, Baltimore, MD (United States)

    2011-11-18

    Highlights: Black-Right-Pointing-Pointer Muscarinic receptor agonists stimulated robust human colon cancer cell invasion. Black-Right-Pointing-Pointer Anti-matrix metalloproteinase1 antibody pre-treatment blocks cell invasion. Black-Right-Pointing-Pointer Bile acids stimulate MMP1 expression, cell migration and MMP1-dependent invasion. -- Abstract: Mammalian matrix metalloproteinases (MMPs) which degrade extracellular matrix facilitate colon cancer cell invasion into the bloodstream and extra-colonic tissues; in particular, MMP1 expression correlates strongly with advanced colon cancer stage, hematogenous metastasis and poor prognosis. Likewise, muscarinic receptor signaling plays an important role in colon cancer; muscarinic receptors are over-expressed in colon cancer compared to normal colon epithelial cells. Muscarinic receptor activation stimulates proliferation, migration and invasion of human colon cancer cells. In mouse intestinal neoplasia models genetic ablation of muscarinic receptors attenuates carcinogenesis. In the present work, we sought to link these observations by showing that MMP1 expression and activation plays a mechanistic role in muscarinic receptor agonist-induced colon cancer cell invasion. We show that acetylcholine, which robustly increases MMP1 expression, stimulates invasion of HT29 and H508 human colon cancer cells into human umbilical vein endothelial cell monolayers - this was abolished by pre-incubation with atropine, a non-selective muscarinic receptor inhibitor, and by pre-incubation with anti-MMP1 neutralizing antibody. Similar results were obtained using a Matrigel chamber assay and deoxycholyltaurine (DCT), an amidated dihydroxy bile acid associated with colon neoplasia in animal models and humans, and previously shown to interact functionally with muscarinic receptors. DCT treatment of human colon cancer cells resulted in time-dependent, 10-fold increased MMP1 expression, and DCT-induced cell invasion was also blocked by pre

  5. Matrix metalloproteinase-12 gene regulation by a PPAR alpha agonist in human monocyte-derived macrophages

    International Nuclear Information System (INIS)

    Souissi, Imen Jguirim; Billiet, Ludivine; Cuaz-Perolin, Clarisse; Slimane, Mohamed-Naceur; Rouis, Mustapha

    2008-01-01

    MMP-12, a macrophage-specific matrix metalloproteinase with large substrate specificity, has been reported to be highly expressed in mice, rabbits and human atherosclerotic lesions. Increased MMP-12 from inflammatory macrophages is associated with several degenerative diseases such as atherosclerosis. In this manuscript, we show that IL-1β, a proinflammatory cytokine found in atherosclerotic plaques, increases both mRNA and protein levels of MMP-12 in human monocyte-derived macrophages (HMDM). Since peroxisome proliferator-activated receptors (PPARs), such as PPARα and PPARγ, are expressed in macrophages and because PPAR activation exerts an anti-inflammatory effect on vascular cells, we have investigated the effect of PPARα and γ isoforms on MMP-12 regulation in HMDM. Our results show that MMP-12 expression (mRNA and protein) is down regulated in IL-1β-treated macrophages only in the presence of a specific PPARα agonist, GW647, in a dose-dependent manner. In contrast, this inhibitory effect was abolished in IL-1β-stimulated peritoneal macrophages isolated from PPARα -/- mice and treated with the PPARα agonist, GW647. Moreover, reporter gene transfection experiments using different MMP-12 promoter constructs showed a reduction of the promoter activities by ∼ 50% in IL-1β-stimulated PPARα-pre-treated cells. However, MMP-12 promoter analysis did not reveal the presence of a PPRE response element. The IL-1β effect is known to be mediated through the AP-1 binding site. Mutation of the AP-1 site, located at - 81 in the MMP-12 promoter region relative to the transcription start site, followed by transfection analysis, gel shift and ChIP experiments revealed that the inhibitory effect was the consequence of the protein-protein interaction between GW 647-activated PPARα and c-Fos or c-Jun transcription factors, leading to inhibition of their binding to the AP-1 motif. These studies suggest that PPARα agonists may be used therapeutically, not only for lipid

  6. Pharmacological, neurochemical, and behavioral profile of JB-788, a new 5-HT1A agonist.

    Science.gov (United States)

    Picard, M; Morisset, S; Cloix, J F; Bizot, J C; Guerin, M; Beneteau, V; Guillaumet, G; Hevor, T K

    2010-09-01

    A novel pyridine derivative, 8-{4-[(6-methoxy-2,3-dihydro-[1,4]dioxino[2,3-b]pyridine-3-ylmethyl)-amino]-butyl}-8-aza-spiro[4.5]decane-7,9-dione hydrochloride, termed JB-788, was designed to selectively target 5-HT(1A) receptors. In the present study, the pharmacological profile of JB-788 was characterized in vitro using radioligands binding tests and in vivo using neurochemical and behavioural experiments. JB-788 bound tightly to human 5-HT(1A) receptor expressed in human embryonic kidney 293 (HEK-293) cells with a K(i) value of 0.8 nM. Its binding affinity is in the same range as that observed for the (+/-)8-OH-DPAT, a reference 5HT(1A) agonist compound. Notably, JB-788 only bound weakly to 5-HT(1B) or 5-HT(2A) receptors and moreover the drug displayed only weak or indetectable binding to muscarinic, alpha(2), beta(1) and beta(2) adrenergic receptors, or dopaminergic D(1) receptors. JB-788 was found to display substantial binding affinity for dopaminergic D(2) receptors and, to a lesser extend to alpha(1) adrenoreceptors. JB-788 dose-dependently decreased forskolin-induced cAMP accumulation in HEK cells expressing human 5-HT(1A), thus acting as a potent 5-HT(1A) receptor agonist (E(max.) 75%, EC(50) 3.5 nM). JB-788 did not exhibit any D(2) receptor agonism but progressively inhibited the effects of quinpirole, a D(2) receptor agonist, in the cAMP accumulation test with a K(i) value of 250 nM. JB-788 induced a weak change in cAMP levels in mouse brain but, like some antipsychotics, transiently increased glycogen contents in various brain regions. Behavioral effects were investigated in mice using the elevated plus-maze. JB-788 was found to increase the time duration spent by animals in anxiogenic situations. Locomotor hyperactivity induced by methamphetamine in mouse, a model of antipsychotic activity, was dose-dependently inhibited by JB-788. Altogether, these results suggest that JB-788 displays pharmacological properties, which could be of interest in the area

  7. Ursodeoxycholic Acid Suppresses Lipogenesis in Mouse Liver: Possible Role of the Decrease in β-Muricholic Acid, a Farnesoid X Receptor Antagonist.

    Science.gov (United States)

    Fujita, Kyosuke; Iguchi, Yusuke; Une, Mizuho; Watanabe, Shiro

    2017-04-01

    The farnesoid X receptor (FXR) is a major nuclear receptor of bile acids; its activation suppresses sterol regulatory element-binding protein 1c (SREBP1c)-mediated lipogenesis and decreases the lipid contents in the liver. There are many reports showing that the administration of ursodeoxycholic acid (UDCA) suppresses lipogenesis and reduces the lipid contents in the liver of experimental animals. Since UDCA is not recognized as an FXR agonist, these effects of UDCA cannot be readily explained by its direct activation of FXR. We observed that the dietary administration of UDCA in mice decreased the expression levels of SREBP1c and its target lipogenic genes. Alpha- and β-muricholic acids (MCA) and cholic acid (CA) were the major bile acids in the mouse liver but their contents decreased upon UDCA administration. The hepatic contents of chenodeoxycholic acid and deoxycholic acid (DCA) were relatively low but were not changed by UDCA. UDCA did not show FXR agonistic or antagonistic potency in in vitro FXR transactivation assay. Taking these together, we deduced that the above-mentioned change in hepatic bile acid composition induced upon UDCA administration might cause the relative increase in the FXR activity in the liver, mainly by the reduction in the content of β-MCA, a farnesoid X receptor antagonist, which suggests a mechanism by which UDCA suppresses lipogenesis and decreases the lipid contents in the mouse liver.

  8. Structural differences in the two agonist binding sites of the Torpedo nicotinic acetylcholine receptor revealed by time-resolved fluorescence spectroscopy

    DEFF Research Database (Denmark)

    Martinez, K. L.; Corringer, P. J.; Edelstein, S. J.

    2000-01-01

    The nicotinic acetylcholine receptor (nAChR) from Torpedo marmorata carries two nonequivalent agonist binding sites at the αδ and αγ subunit interfaces. These sites have been characterized by time-resolved fluorescence with the partial nicotinic agonist dansyl-C6-choline (Dnscho). When bound...

  9. An overview of once-weekly glucagon-like peptide-1 receptor agonists--available efficacy and safety data and perspectives for the future

    DEFF Research Database (Denmark)

    Madsbad, S; Kielgast, U; Asmar, M

    2011-01-01

    Incretin-based therapies, such as the injectable glucagon-like peptide-1 (GLP-1) receptor agonists and orally administered dipeptidyl peptidase-4 (DPP-4) inhibitors, have recently been introduced into clinical practice. At present, the GLP-1 receptor agonists need to be administered once or twice...

  10. Aortic valve calcification and mild tricuspid regurgitation but no clinical heart disease after 8 years of dopamine agonist therapy for prolactinoma

    NARCIS (Netherlands)

    Kars, Marleen; Delgado, Victoria; Holman, Eduard R.; Feelders, Richard A.; Smit, Johannes W. A.; Romijn, Johannes A.; Bax, Jeroen J.; Pereira, Alberto M.

    2008-01-01

    Treatment with ergot-derived dopamine agonists, pergolide, and cabergoline has been associated with an increased frequency of valvular heart disease in Parkinson's disease. The aim of the present study was to assess the prevalence of valvular heart disease in patients treated with dopamine agonists

  11. Involvement of the Retinoid X Receptor Ligand in the Anti-Inflammatory Effect Induced by Peroxisome Proliferator-Activated Receptor Agonist In Vivo

    Directory of Open Access Journals (Sweden)

    Atsuki Yamamoto

    2011-01-01

    Full Text Available Peroxisome proliferator-activated receptor γ (PPARγ forms a heterodimeric DNA-binding complex with retinoid X receptors (RXRs. It has been reported that the effect of the PPAR agonist is reduced in hepatocyte RXR-deficient mice. Therefore, it is suggested that the endogenous RXR ligand is involved in the PPARγ agonist-induced anti-inflammatory effect. However, the participation of the RXR ligand in the PPARγ-induced anti-inflammatory effect is unknown. Here, we investigated the influence of RXR antagonist on the anti-inflammatory effect of PPARγ agonist pioglitazone in carrageenan test. In addition, we also examined the influence of PPAR antagonist on the anti-inflammatory effect induced by RXR agonist NEt-3IP. The RXR antagonist suppressed the antiedema effect of PPARγ agonist. In addition, the anti-inflammatory effect of RXR agonist was suppressed by PPARγ antagonist. PPARγ agonist-induced anti-inflammatory effects were reversed by the RXR antagonist. Thus, we showed that the endogenous RXR ligand might contribute to the PPARγ agonist-induced anti-inflammatory effect.

  12. Can dopamine agonists reduce the incidence and severity of OHSS in IVF/ICSI treatment cycles? A systematic review and meta-analysis

    NARCIS (Netherlands)

    Youssef, Mohamed A. F. M.; van Wely, Madelon; Hassan, Mohamed Ahmed; Al-Inany, Hesham Gaber; Mochtar, Monique; Khattab, Sherif; van der Veen, Fulco

    2010-01-01

    Recently, dopamine agonists were proposed as a prophylactic treatment for ovarian hyperstimulation syndrome (OHSS) in women at high risk in IVF/ICSI treatment cycles. We conducted a systematic review and meta-analysis of randomized trials comparing the prophylactic effect of the dopamine agonist,

  13. Stereoselectivity at the B2-adrenoceptor on macrophages is a major determinant of the anti-inflammatory effects of B2-agonists

    NARCIS (Netherlands)

    Izeboud, C.A.; Vermeulen, R.M.; Zwart, A.; Vos, H.P.; Miert, A.S.J.P.A.M. van; Witkamp, R.F.

    2000-01-01

    Previous research has shown that β-adrenoceptor (β-AR) agonists have potent anti-inflammatory capabilities, e.g. represented by suppression of release of the proinflammatory cytokines. Aim of this research was to determine whether the effects of β-agonists on LPS-induced TNFα and IL-10 release are

  14. NOpiates: Novel Dual Action Neuronal Nitric Oxide Synthase Inhibitors with μ-Opioid Agonist Activity.

    Science.gov (United States)

    Renton, Paul; Green, Brenda; Maddaford, Shawn; Rakhit, Suman; Andrews, John S

    2012-03-08

    A novel series of benzimidazole designed multiple ligands (DMLs) with activity at the neuronal nitric oxide synthase (nNOS) enzyme and the μ-opioid receptor was developed. Targeting of the structurally dissimilar heme-containing enzyme and the μ-opioid GPCR was predicated on the modulatory role of nitric oxide on μ-opioid receptor function. Structure-activity relationship studies yielded lead compound 24 with excellent nNOS inhibitory activity (IC50 = 0.44 μM), selectivity over both endothelial nitric oxide synthase (10-fold) and inducible nitric oxide synthase (125-fold), and potent μ-opioid binding affinity, K i = 5.4 nM. The functional activity as measured in the cyclic adenosine monosphospate secondary messenger assay resulted in full agonist activity (EC50 = 0.34 μM). This work represents a novel approach in the development of new analgesics for the treatment of pain.

  15. Pulmonary Artery Occlusion and Mediastinal Fibrosis in a Patient on Dopamine Agonist Treatment for Hyperprolactinemia

    DEFF Research Database (Denmark)

    Su, Junjing; Simonsen, Ulf; Carlsen, Jørn

    2017-01-01

    Unusual forms of pulmonary hypertension include pulmonary hypertension related to mediastinal fibrosis and the use of serotonergic drugs. Here, we describe a patient with diffuse mediastinal fibrosis and pulmonary hypertension while she was on dopamine agonist therapy. A young woman, who...... showed fibrosis and chronic inflammation. Subsequent investigations revealed that diffuse mediastinal fibrosis with concurrent pulmonary hypertension, and not CTEPH, was the most likely diagnosis and cabergoline and bromocriptine may have triggered the fibrotic changes. Both drugs are ergot...... was treated with cabergoline and bromocriptine for hyperprolactinemia, presented with progressive dyspnea over several months. Based on the clinical investigation results, in particular, elevated pulmonary arterial pressures and significant perfusion defects on computed tomography (CT) pulmonary angiography...

  16. Anti-tumor Activity of Toll-Like Receptor 7 Agonists

    Directory of Open Access Journals (Sweden)

    Huju Chi

    2017-05-01

    Full Text Available Toll-like receptors (TLRs are a class of pattern recognition receptors that play a bridging role in innate immunity and adaptive immunity. The activated TLRs not only induce inflammatory responses, but also elicit the development of antigen specific immunity. TLR7, a member of TLR family, is an intracellular receptor expressed on the membrane of endosomes. TLR7 can be triggered not only by ssRNA during viral infections, but also by immune modifiers that share a similar structure to nucleosides. Its powerful immune stimulatory action can be potentially used in the anti-tumor therapy. This article reviewed the anti-tumor activity and mechanism of TLR7 agonists that are frequently applied in preclinical and clinical investigations, and mainly focused on small synthetic molecules, including imiquimod, resiquimod, gardiquimod, and 852A, etc.

  17. Historical Overview of the Effect of -Adrenergic Agonists on Beef Cattle Production

    Directory of Open Access Journals (Sweden)

    Bradley J. Johnson

    2014-05-01

    Full Text Available Postnatal muscle hypertrophy of beef cattle is the result of enhanced myofibrillar protein synthesis and reduced protein turnover. Skeletal muscle hypertrophy has been studied in cattle fed β-adrenergic agonists (β-AA, which are receptor-mediated enhancers of protein synthesis and inhibitors of protein degradation. Feeding β-AA to beef cattle increases longissimus muscle cross-sectional area 6% to 40% compared to non-treated cattle. The β-AA have been reported to improve live animal performance, including average daily gain, feed efficiency, hot carcass weight, and dressing percentage. Treatment with β-AA increased mRNA concentration of the β2 or β1-adrenergic receptor and myosin heavy chain IIX in bovine skeletal muscle tissue. This review will examine the effects of skeletal muscle and adipose development with β-AA, and will interpret how the use of β-AA affects performance, body composition, and growth in beef cattle.

  18. Treatment potential of the GLP-1 receptor agonists in type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Østergaard, L; Frandsen, Christian S.; Madsbad, S

    2016-01-01

    Over the last decade, the discovery of glucagon-like peptide 1 receptor agonists (GLP-1 RAs) has increased the treatment options for patients with type 2 diabetes mellitus (T2DM). GLP-1 RAs mimic the effects of native GLP-1, which increases insulin secretion, inhibits glucagon secretion, increases...... satiety and slows gastric emptying. This review evaluates the phase III trials for all approved GLP-1 RAs and reports that all GLP-1 RAs decrease HbA1c, fasting plasma glucose, and lead to a reduction in body weight in the majority of trials. The most common adverse events are nausea and other...... gastrointestinal discomfort, while hypoglycaemia is rarely reported when GLP-1 RAs not are combined with sulfonylurea or insulin. Treatment options in the near future will include co-formulations of basal insulin and a GLP-1 RA....

  19. Novel GLP-1 fusion chimera as potent long acting GLP-1 receptor agonist.

    Directory of Open Access Journals (Sweden)

    Qinghua Wang

    2010-09-01

    Full Text Available GLP-1 has a variety of anti-diabetic effects. However, native GLP-1 is not suitable for therapy of diabetes due to its short half-life (t1/2168 h. Intraperitoneal glucose tolerance test (IPGTT in mice showed that GLP-1/hIgG2 significantly decreased glucose excursion. Furthermore, IPGTT performed on mice one week after a single drug-injection also displayed significantly reduced glucose excursion, indicating that GLP-1/hIgG2 fusion protein has long-lasting effects on the modulation of glucose homeostasis. GLP-1/hIgG2 was found to be effective in reducing the incidence of diabetes in multiple-low-dose streptozotocin-induced type 1 diabetes in mice. Together, the long-lasting bioactive GLP-1/hIgG2 retains native GLP-1 activities and thus may serve as a potent GLP-1 receptor agonist.

  20. PPARγ agonist pioglitazone reduces matrix metalloproteinase-9 activity and neuronal damage after focal cerebral ischemia

    International Nuclear Information System (INIS)

    Lee, Seong-Ryong; Kim, Hahn-Young; Hong, Jung-Suk; Baek, Won-Ki; Park, Jong-Wook

    2009-01-01

    Pioglitazone, a peroxisome proliferator-activated receptor gamma (PPARγ) agonist, has shown protective effects against ischemic insult in various tissues. Pioglitazone is also reported to reduce matrix metalloproteinase (MMP) activity. MMPs can remodel extracellular matrix components in many pathological conditions. The current study was designed to investigate whether the neuroprotection of pioglitazone is related to its MMP inhibition in focal cerebral ischemia. Mice were subjected to 90 min focal ischemia and reperfusion. In gel zymography, pioglitazone reduced the upregulation of active form of MMP-9 after ischemia. In in situ zymograms, pioglitazone also reduced the gelatinase activity induced by ischemia. After co-incubation with pioglitazone, in situ gelatinase activity was directly reduced. Pioglitazone reduced the infarct volume significantly compared with controls. These results demonstrate that pioglitazone may reduce MMP-9 activity and neuronal damage following focal ischemia. The reduction of MMP-9 activity may have a possible therapeutic effect for the management of brain injury after focal ischemia.