[show abstract][hide abstract] ABSTRACT: Chronic glucocorticoid excess has been linked to increased atherosclerosis and general cardiovascular risk in humans. The enzyme 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1) increases active glucocorticoid levels within tissues by catalyzing the conversion of cortisone to cortisol. Pharmacological inhibition of 11βHSD1 has been shown to reduce atherosclerosis in murine models. However, the cellular and molecular details for this effect have not been elucidated.
To examine the role of 11βHSD1 in atherogenesis, 11βHSD1 knockout mice were created on the pro-atherogenic apoE(-/-) background. Following 14 weeks of Western diet, aortic cholesterol levels were reduced 50% in 11βHSD1(-/-)/apoE(-/-) mice vs. 11βHSD1(+/+)/apoE(-/-) mice without changes in plasma cholesterol. Aortic 7-ketocholesterol content was reduced 40% in 11βHSD1(-/-)/apoE(-/-) mice vs. control. In the aortic root, plaque size, necrotic core area and macrophage content were reduced ∼30% in 11βHSD1(-/-)/apoE(-/-) mice. Bone marrow transplantation from 11βHSD1(-/-)/apoE(-/-) mice into apoE(-/-) recipients reduced plaque area 39-46% in the thoracic aorta. In vivo foam cell formation was evaluated in thioglycollate-elicited peritoneal macrophages from 11βHSD1(+/+)/apoE(-/-) and 11βHSD1(-/-)/apoE(-/-) mice fed a Western diet for ∼5 weeks. Foam cell cholesterol levels were reduced 48% in 11βHSD1(-/-)/apoE(-/-) mice vs. control. Microarray profiling of peritoneal macrophages revealed differential expression of genes involved in inflammation, stress response and energy metabolism. Several toll-like receptors (TLRs) were downregulated in 11βHSD1(-/-)/apoE(-/-) mice including TLR 1, 3 and 4. Cytokine release from 11βHSD1(-/-)/apoE(-/-)-derived peritoneal foam cells was attenuated following challenge with oxidized LDL.
These findings suggest that 11βHSD1 inhibition may have the potential to limit plaque development at the vessel wall and regulate foam cell formation independent of changes in plasma lipids. The diminished cytokine response to oxidized LDL stimulation is consistent with the reduction in TLR expression and suggests involvement of 11βHSD1 in modulating binding of pro-atherogenic TLR ligands.
PLoS ONE 01/2013; 8(2):e53192. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Derived from the HTS hit 1, a series of hydroxyisoquinolines was discovered as potent and selective 11β-HSD1 inhibitors with good cross species activity. Optimization of substituents at the 1 and 4 positions of the isoquinoline group in addition to the core modifications, with a special focus on enhancing metabolic stability and aqueous solubility, resulted in the identification of several compounds as potent advanced leads.
[show abstract][hide abstract] ABSTRACT: Starting from high throughput screening hit 2-adamantyl acetic acid 3, a series of polycyclic acids have been designed and synthesized as novel, potent, and selective inhibitors of human 11β-HSD-1. Structure-activity relationships of two different regions of the chemotype (polycyclic ring and substituents on quaternary carbon) are discussed.
[show abstract][hide abstract] ABSTRACT: A series of pyridyl amide/sulfonamide inhibitors of 11β-HSD-1 were modified to incorporate a novel 1,2,4-triazolopyridine scaffold. Optimization of substituents at the 3 and 8 position of the TZP core, with a special focus on enhancing metabolic stability, resulted in the identification of compound 38 as a potent and metabolically stable inhibitor of the enzyme.
[show abstract][hide abstract] ABSTRACT: Identification and quantitation of drug metabolites are important for understanding and predicting drug-drug interactions and toxicities. For chiral compounds, metabolic interconversion of enantiomers may present unique challenges. If the stereoisomers are biologically distinguishable, regulatory agencies consider them distinct chemical entities and require individual characterization since enantiomers may exhibit different pharmacokinetic, pharmacologic, and toxicologic properties. Efforts to predict enantiomeric ratios in humans from animal studies are frequently hampered by a lack of understanding of the enzymes responsible and potential interspecies differences. In this study, liver microsomes from rats, dogs, and monkeys were used to investigate the kinetics of interconversion of two enantiomeric secondary alcohols (Compounds A and C) via oxidation to a ketone intermediate (Compound B) and subsequent reduction of the ketone to either regenerate the starting alcohol, or produce the enantiomer. A mechanistic model was established using in vitro microsomal data to predict the ratios of the enantiomer concentrations in plasma 24 hours after dosing and the ratios of AUC values for the enantiomers. Plasma concentrations of the enantiomers and ketone intermediate were determined after single intravenous and oral doses of Compound C. The observed concentration and AUC ratios were similar to the values predicted by the mechanistic model.
Journal of Pharmaceutical Sciences 07/2010; 99(7):3234-45. · 3.13 Impact Factor
[show abstract][hide abstract] ABSTRACT: The orexigenic peptide ghrelin has been shown to have prokinetic activity in the gastrointestinal (GI) system of several species, including humans. In this series of experiments, we have evaluated the prokinetic activity of novel, small-molecule ghrelin receptor (GhrR) agonists after parenteral and peroral dosing in mice and rats. Gastric emptying, small intestinal transport, and fecal output were determined after intraperitoneal and intracerebroventricular dosing of GhrR agonists, using ghrelin as a positive control. These same parameters were evaluated after oral gavage dosing of the synthetic agonists. Regardless of dose route, GhrR agonist treatment increased gastric emptying, small intestinal transit, and fecal output. However, fecal output was only increased by GhrR agonist treatment if mice were able to feed during the stimulatory period. Thus, GhrR agonists can stimulate upper GI motility, and the orexigenic action of the compounds can indirectly contribute to prokinetic activity along the entire GI tract. The orexigenic and prokinetic effects of either ghrelin or small-molecule GhrR agonists were selective for the GhrR because they were absent when evaluated in GhrR knockout mice. We next evaluated the efficacy of the synthetic GhrR agonists dosed in a model of opiate-induced bowel dysfunction induced by a single injection of morphine. Oral dosing of a GhrR agonist normalized GI motility in opiate-induced dysmotility. These data demonstrate the potential utility of GhrR agonists for treating gastrointestinal hypomotility disorders.
Journal of Pharmacology and Experimental Therapeutics 03/2009; 329(3):1178-86. · 3.89 Impact Factor
[show abstract][hide abstract] ABSTRACT: The discovery and optimization of a novel series of prolinol-derived GHSR agonists is described. This series emerged from a 11,520-member solid-phase library targeting the GPCR protein superfamily, and the rapid optimization of low micromolar hits into single-digit nanomolar leads can be attributed to the solid-phase synthesis of matrix libraries, which revealed multiple non-additive structure-activity relationships. In addition, the separation of potent diastereomers highlighted the influence of the alpha-methyl stereochemistry of the phenoxyacetamide sidechain on GHSR activity.
[show abstract][hide abstract] ABSTRACT: The first enantioselective synthesis of (D)-2-tert-butoxycarbonylamino-5,5-difluoro-5-phenyl-pentanoic acid 3 was achieved. The incorporation of the titled compound into growth hormone secretagogue (GHS) compounds resulted in new analogs 10 and 16, both of which had significantly increased in vitro potency. The compound 10 also showed improved in vivo efficacy as well as pharmacokinetic properties in rat models.
[show abstract][hide abstract] ABSTRACT: Several series of pyridine amides were identified as selective and potent 11beta-HSD1 inhibitors. The most potent inhibitors feature 2,6- or 3,5-disubstitution on the pyridine core. Various linkers (CH(2)SO(2), CH(2)S, CH(2)O, S, O, N, bond) between the distal aryl and central pyridyl groups are tolerated, and lipophilic amide groups are generally favored. On the distal aryl group, a number of substitutions are well tolerated. A crystal structure was obtained for a complex between 11beta-HSD1 and the most potent inhibitor in this series.
[show abstract][hide abstract] ABSTRACT: A novel series of N1 substituted tetrazole amides were prepared and showed to be potent growth hormone (GH) secretagogues. Among them, hydroxyl containing analog 31 displayed excellent in vivo activity by increasing plasma GH 10-fold in an anesthetized IV rat model.
[show abstract][hide abstract] ABSTRACT: The structure-activity relationship of the O-benzyl serine side chain was investigated based on the tetrazole-based growth hormone secretagogue BMS-317180 (2). The ortho position of the benzyl moiety was found to be favorable for introduction of substituents. A series of ortho-substituted compounds were synthesized with improved in-vitro and in-vivo activity. Among them, the biphenyl compound 2p shows twofold improvement in potency compared to its parent compound BMS-317180 (2).
[show abstract][hide abstract] ABSTRACT: 1H-tetrazole-1-alkanenitrile SR-9g exhibits a >10-fold in vivo potency enhancement over the lead nitrile 1 and has acceptable oral bioavailability in rats and dogs. An enantiospecific synthesis of 1H-tetrazole-1-alkanenitrile nitriles 9 has been developed.
[show abstract][hide abstract] ABSTRACT: A novel class of Growth Hormone Secretagogues (GHS), based on a tetrazole template, has been discovered. In vitro SAR and in vivo potency within this new class of GHS are described. The tetrazole 9q exhibits good oral bioavailability in rats and dogs as well as efficacy following an oral 10 mg/kg dose in dogs. Solution and solid phase protocols for the synthesis of tetrazole based GHS have been developed.
[show abstract][hide abstract] ABSTRACT: A tetrazole-based peptidomimetic 2 (BMS-317180) was discovered as a human growth hormone secretagogue (GHS). Compound 2 is a potent, novel, orally effective GHS that shows an excellent safety profile in preclinical studies. The compound was advanced into clinical development.
Journal of Medicinal Chemistry 12/2007; 50(24):5890-3. · 5.61 Impact Factor
[show abstract][hide abstract] ABSTRACT: 11beta-hydroxysteroid dehydrogenase 1 regulates the tissue availability of cortisol by interconverting cortisone and cortisol. It is capable of functioning as both a reductase and a dehydrogenase depending upon the surrounding milieu. In this work, we have studied the reaction mechanism of a soluble form of human 11beta-hydroxysteroid dehydrogenase 1 and its mode of inhibition by potent and selective inhibitors belonging to three different structural classes. We found that catalysis follows an ordered addition with NADP(H) binding preceding the binding of the steroid. While all three inhibitors tested bound to the steroid binding pocket, they differed in their interactions with the cofactor NADP(H). Compound A, a pyridyl amide bound more efficiently to the NADPH-bound form of 11beta-hydroxysteroid dehydrogenase 1. Compound B, an adamantyl triazole, was unaffected by NADP(H) binding and the sulfonamide, Compound C, showed preferential binding to the NADP+ -bound form of 11beta-hydroxysteroid dehydrogenase 1. These differences were found to augment significant selectivity towards inhibition of the reductase reaction versus the dehydrogenase reaction. This selectivity may translate to differences in the in vivo effects of 11beta-hydroxysteroid dehydrogenase 1 inhibitors.
Biochimica et Biophysica Acta 10/2007; 1774(9):1184-91. · 4.66 Impact Factor
[show abstract][hide abstract] ABSTRACT: The motilin receptor (MR) is a member of the seven-transmembrane receptor family and is expressed throughout the gastrointestinal tract of humans and other species. Motilin, the natural MR peptide ligand, has profound stimulatory effects on gastrointestinal contractility, indicating a therapeutic potential for MR modulators. However, long-term clinical use of certain MR agonists is limited by tachyphylaxis, a reduced responsiveness to repeated compound exposure. This study was meant to characterize the ligand-induced endocytosis of MR and to test whether receptor trafficking contributes to tachyphylaxis. A cell-based assay was developed by fusing a green fluorescent protein (GFP) moiety to the motilin receptor, and high-content biology instrumentation was used to quantify time and dose dependence of MR-GFP endocytosis. Maximal internalization of MR-GFP was induced after 45 min of constant exposure to 80 nM motilin. This process was disrupted by nocodazole, suggesting an essential role for microtubules. Internalized MR-GFP vesicles disappeared within 15 to 45 min of motilin withdrawal but did not overlap with the lysosomal compartment, indicating that MR-GFP escaped degradation and was recycled back to the plasma membrane. It is noteworthy that the kinetics of MR-GFP redistribution varied substantially when stimulated with motilin, erythromycin, 6,9-hemiacetal 8,9-anhydro-4''-deoxy-3'-N-desmethyl-3'-N-ethylerythromycin B (ABT-229), or N-[(1S)-1-[[[(1S)-1-(aminocarbonyl)-3-phenylpropyl]amino]carbonyl]-3-phenylpropyl]-2'-(1,3-benzodioxol-5-ylmethyl)tetrahydro-1',3'-dioxo-spiro[piperidine-4,5'(6'H)-[1H][1,2,4]triazolo[1,2-a]pyridazine]-8'-carboxamide (BMS-591348) at equipotent doses for Ca(2+)-mobilization. Retardation of the intracellular MR-GFP sorting cycle seemed to correlate with the tachyphylaxis-inducing properties of each compound, but not its EC(50). These results indicate that MR internalization, desensitization, and resensitization are ligand-dependent and that appropriate screening strategies may enable the development of small molecule agonists with ideal combinations of these distinct properties.
[show abstract][hide abstract] ABSTRACT: Several novel series of tetrahydroisoquinoline 1-carboxamides were prepared and shown to be potent growth hormone (GH) secretagogues. Among them, carbamate 12a-E2 displays excellent in vivo activity by increasing plasma GH 10-fold in an anesthetized IV rat model.
[show abstract][hide abstract] ABSTRACT: A novel series of dihydro- and tetrahydrotriazolopyridazine-1,3-dione-based amino acid derivatives were identified as very potent motilin receptor agonists. Incorporating one additional phenylethyl glycinamide subunit to 1 (EC(50) = 660 nM) was found to improve in vitro potency approximately 3000-fold, resulting in compound 10 (EC(50) = 0.22 nM). The more potent enantiomer 11A has an EC(50) of 0.047 nM in the motilin receptor functional assay and a K(i) of 0.7 nM in the binding assay. In addition, compound 11A was shown to have a significantly reduced tendency to cause receptor desensitization as compared with the motilin receptor agonist ABT-229.
Journal of Medicinal Chemistry 04/2004; 47(7):1704-8. · 5.61 Impact Factor