ABSTRACT
Voiding dysfunctions, including increased voiding frequency, urgency, or incontinence, are prevalent in the postmenopausal population. Beta(3)-adrenergic receptor (beta(3)AR) agonists, which relax bladder smooth muscle, are being developed to treat these conditions. We utilized the rat ovariectomy (OVX) model to investigate the effect of ovarian hormone depletion on bladder function and the potential for beta(3)AR agonists to treat bladder hyperactivity in this setting. OVX increased voiding frequency and decreased bladder capacity by approximately 25% in awake rats and induced irregular cystometrograms in urethane-anesthetized rats. Reverse transcription-polymerase chain reaction revealed three betaARs subtypes (beta(1,2,3)) in bladder tissue, and immunostaining indicated beta(3)AR localization in urothelium and detrusor. Receptor expression was not different in OVX and SHAM rats. The beta(3)AR agonist selectivity of BRL37344 [(+/-)-(R(*),R(*))-[4-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]phenoxy]acetic acid sodium hydrate], TAK-677 [(3-((2R)-(((2R)-(3-chlorophenyl)-2-hydroxyethyl)amino)propyl)-1H-indol-7-yloxy)acetic acid], and FK175 [acetic acid, 2-[[(8S)-8-[[(2R)-2-(3-chlorophenyl)-2-hydroxyethyl]amino]-6,7,8,9-tetrahydro-5H-benzocyclohepten-2-yl]oxy], ethyl ester, hydrochloride] was confirmed by examining the relative potency for elevation of cAMP in CHOK1 cells overexpressing the various rat betaARs. Intravenous injection of each of the beta(3)AR agonists (0.1-500 microg/kg) in anesthetized rats decreased voiding frequency, bladder pressure, and amplitude of bladder contractions. In bladder strips, beta(3)AR agonists (10(-12)-10(-4) M) decreased baseline tone and reduced spontaneous contractions. BRL37344 (5 mg/kg) and TAK-677 (5 mg/kg) injected intraperitoneally in awake rats decreased voiding frequency by 40 to 70%. These effects were not altered by OVX. The results indicate that OVX-induced bladder dysfunction, including decreased bladder capacity and increased voiding frequency, is not associated with changes in beta(3)AR expression or the bladder inhibitory effects of beta(3)AR agonists. This suggests that beta(3)AR agonists should prove effective for the treatment of overactive bladder symptoms in the postmenopausal population.
Subject(s)
Adrenergic beta-3 Receptor Agonists , Adrenergic beta-Agonists/pharmacology , Ovariectomy , Urinary Bladder, Neurogenic/drug therapy , Adrenergic beta-Agonists/chemical synthesis , Anesthesia , Animals , CHO Cells , Cricetinae , Cricetulus , Cyclic AMP/metabolism , Female , Humans , Immunohistochemistry , In Vitro Techniques , Muscle, Smooth/drug effects , Muscle, Smooth/physiology , Rats , Rats, Sprague-Dawley , Receptors, Adrenergic, beta-3/biosynthesis , Urinary Bladder, Neurogenic/physiopathology , Urination/drug effectsABSTRACT
A study that was designed to identify plausible replacements for highly basic guanidine moiety contained in potent MC4R agonists, as exemplified by 1, led to the discovery of initial nonguanidine lead 5. Propyl analog 23 was subsequently found to be equipotent to 5, whereas analogs bearing smaller and branched alkyl groups at the 3 position of the oxopiperazine template demonstrated reduced binding affinity and agonist potency for MC4R. Acylation of the NH2 group of the 4F-D-Phe residue of 3-propyl analog 23 significantly increased the binding affinity and the functional activity for MC4R. Analogs with neutral and weakly basic capping groups of the D-Phe residue exhibited excellent MC4R selectivity against MC1R whereas those with an amino acid had moderate MC4R/MC1R selectivity. We have also demonstrated that compound 35 showed promising oral bioavailability and a moderate oral half life and induced significant weight loss in a 28-day rat obesity model.
Subject(s)
Anti-Obesity Agents/pharmacology , Anti-Obesity Agents/therapeutic use , Obesity/drug therapy , Piperazines/pharmacology , Piperazines/therapeutic use , Receptor, Melanocortin, Type 4/agonists , Administration, Oral , Animals , Anti-Obesity Agents/chemistry , Biological Availability , Diet , Disease Models, Animal , Dogs , Drug Design , Drug Evaluation, Preclinical , Eating/drug effects , Male , Molecular Conformation , Piperazines/chemistry , Rats , StereoisomerismABSTRACT
The melanin-concentrating hormone-1 receptor (MCH1R) is a G-protein-coupled receptor expressed in the brain and peripheral tissues that regulates energy storage and body weight. Here, we focused on discovery of the mechanism and site of action for a small-molecule MCH1R antagonist, which yields weight loss in a mouse model of human obesity. MCH1R is expressed throughout the brain but also found in peripheral tissues known to regulate fat storage and utilization, e.g., skeletal muscle and adipose tissue. Previous studies of MCH1R antagonist studies have not delineated the site that is critical for mediating the anorexigenic and weight-reducing actions. In this study, we evaluated the role of the brain and peripheral tissue receptors. We developed a novel nonbrain-permeable MCH antagonist analog with a carboxylic acid moiety to specifically test the site of action. Based on in vitro and in vivo assays, the analog is not able to cross the blood-brain barrier and does not lead to inhibition of food intake and reduced body weight. The data clearly demonstrate that MCH1R antagonists need access to the brain to reduce body weight and fat mass. The brain-permeable MCH1R antagonist leads to significant reduction in body weight and fat mass in diet-induced obese mice. The effect is dose-dependent and appears to be partially driven by a reduction in food intake. Finally, these studies show the utility of a medicinal chemistry approach to address an important biological and pharmacological question.
Subject(s)
Anti-Obesity Agents/therapeutic use , Brain/metabolism , Obesity/drug therapy , Receptors, Somatostatin/antagonists & inhibitors , Animals , Anti-Obesity Agents/metabolism , Anti-Obesity Agents/pharmacokinetics , Avoidance Learning , Body Weight/drug effects , Caco-2 Cells , Cell Line , Dietary Fats/pharmacology , Eating/drug effects , Humans , Male , Mice , Mice, Inbred C57BL , Rats , Rats, Long-Evans , Receptors, Somatostatin/metabolism , TasteABSTRACT
Despite the high number of drug-discovery programs dedicated to finding small-molecule MCH-R1 antagonists for the treatment of obesity and/or mood disorders, a very limited number of these have progressed into the clinic. Beyond the common challenges in drug design related to ADME and safety profiles, cardiovascular risk involving hERG binding and the potential for subsequent drug-induced QTc prolongation has been a major hurdle for a significant number of MCH-R1 research programs. Many of these programs have evolved, and effectively designed MCH antagonists having decreased hERG-binding affinity have emerged. Currently, however, only a selected few candidates have progressed to clinical development. Drug-design strategies, in vivo efficacy, ADME, and cardiovascular safety profiles for a selection of MCH-R1 antagonist research programs are discussed ahead.
Subject(s)
Drug Design , Mood Disorders/drug therapy , Obesity/drug therapy , Receptors, Somatostatin/antagonists & inhibitors , Animals , Clinical Trials as Topic , Humans , Structure-Activity RelationshipABSTRACT
The increasing prevalence of type 2 diabetes has sparked interest in the development of agents that treat and prevent the disease. Mounting evidence indicates that protein tyrosine phosphatase (PTP)1B negatively regulates insulin and leptin signaling making it a prime target for enhancing insulin sensitivity and controlling body mass. Despite intense efforts, development of orally bioavailable small-molecule PTP1B inhibitors has been a challenge. This review focuses on recent advances in the validation of PTP1B and in the development of approaches to modulate its activity.
Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/therapeutic use , Insulin/physiology , Protein Tyrosine Phosphatase, Non-Receptor Type 1/antagonists & inhibitors , Animals , Diabetes Mellitus, Type 2/enzymology , Humans , Leptin/physiology , Protein Tyrosine Phosphatase, Non-Receptor Type 1/genetics , Protein Tyrosine Phosphatase, Non-Receptor Type 1/metabolism , Signal TransductionABSTRACT
The design, synthesis, and biological studies of a novel class of MCH-R1 antagonists based on an aminotetrahydronaphthalene ketopiperazine scaffold is described. Compounds within this class promoted significant body weight reduction in mouse diet induced obesity studies. The potential for hERG blockage activity and QT interval studies in anesthetized dogs are discussed.
Subject(s)
Piperazines/pharmacology , Receptors, Somatostatin/antagonists & inhibitors , Animals , Dogs , Drug Evaluation, Preclinical , Magnetic Resonance Spectroscopy , Male , Mass Spectrometry , Models, Molecular , Piperazines/chemistry , Structure-Activity RelationshipABSTRACT
Aminomethyl tetrahydronaphthalene biphenyl carboxamide MCH-R1 antagonists with greater selectivity over hERG were identified. SAR studies addressing two distinct alternatives for structural modifications leading to improve hERG selectivity are described.
Subject(s)
Biphenyl Compounds/pharmacology , Ether-A-Go-Go Potassium Channels/drug effects , Naphthalenes/pharmacology , Potassium Channel Blockers/pharmacology , Receptors, Somatostatin/antagonists & inhibitors , Biphenyl Compounds/chemical synthesis , ERG1 Potassium Channel , Ergolines/pharmacology , Humans , Indicators and Reagents , Mianserin/pharmacology , Naphthalenes/chemical synthesis , Receptor, Serotonin, 5-HT2C/drug effects , Serotonin Antagonists/pharmacology , Structure-Activity RelationshipABSTRACT
A direct correlation between hERG binding and QTc prolongation was established for a series of aminomethyl tetrahydronaphthalene ketopiperazine MCH-R1 antagonists. Compounds within this class with greater selectivity over hERG were developed. Compound 4h proved to have the best profile, with MCH-R1 Ki = 16 nm and hERG IC50 = 25 microM.
Subject(s)
Ether-A-Go-Go Potassium Channels/drug effects , Naphthalenes/pharmacology , Piperazines/pharmacology , Potassium Channel Blockers/pharmacology , Receptors, Somatostatin/antagonists & inhibitors , Animals , Dogs , ERG1 Potassium Channel , Heart Rate/drug effects , Humans , Indicators and Reagents , Mice , Naphthalenes/chemical synthesis , Piperazines/chemical synthesis , Weight Loss/drug effectsABSTRACT
Peptidomimetic compounds possessing a caprolactam ring constraint were prepared and evaluated as interleukin-1beta converting enzyme (ICE) inhibitors. The caprolactam ring was used to constrain the P3 region of our inhibitors. This strategy proved to be effective for the synthesis of ICE inhibitors, maintaining key hydrogen bond interactions with the enzyme and invoking a preferred conformation for binding. Several compounds exhibited IC(50) values less than 10nM in a caspase-1 enzyme assay and less than 100nM in a THP-1 whole cell assay measuring IL-1beta production. Two compounds, 13c and 13j, were found to have good oral bioavailability (>50%) in rats when administered as prodrugs.
Subject(s)
Caprolactam/chemical synthesis , Caspase Inhibitors , Enzyme Inhibitors/pharmacology , Serpins/chemical synthesis , Viral Proteins/chemical synthesis , Animals , Biological Availability , Caprolactam/chemistry , Caprolactam/pharmacology , Crystallography, X-Ray , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/chemistry , Hydrogen Bonding , Interleukin-1beta/metabolism , Male , Models, Molecular , Molecular Conformation , Molecular Structure , Rats , Rats, Sprague-Dawley , Serpins/pharmacology , Structure-Activity Relationship , Viral Proteins/pharmacologyABSTRACT
The synthesis and biological testing of novel classes of potent melanin-concentrating hormone (MCH-R1) antagonists based on pyrazolopiperazinone and pyrrolopiperazinone scaffolds are described.
Subject(s)
Piperazines/chemical synthesis , Pyrazoles/chemical synthesis , Pyrroles/chemical synthesis , Receptors, Somatostatin/antagonists & inhibitors , Caco-2 Cells , Humans , Indicators and Reagents , Models, Molecular , Molecular Conformation , Piperazines/pharmacology , Pyrazoles/pharmacology , Pyrroles/pharmacology , Radioligand Assay , Receptor, Serotonin, 5-HT2C/drug effectsABSTRACT
A substituted 4-aminopiperidine was identified as showing activity in an MCH assay from an HTS effort. Subsequent structural modification of the scaffold led to the identification of a number of active MCH antagonists. 3,5-Dimethoxy-N-(1-(naphthalen-2-ylmethyl)piperidin-4-yl)benzamide (5c) was among those with the highest binding affinity to the MCH receptor (K(i)=27nM), when variations were made at benzoyl and naphthylmethyl substitution sites from the initial HTS hit. Further optimization via piperidine ring contraction resulted in enhanced MCH activity in a 3-aminopyrrolidine series, where (R)-3,5-dimethoxy-N-(1-(naphthalen-2-ylmethyl)-pyrrolidin-3-yl)benzamide (10i) was found to be an excellent MCH antagonist (K(i)=7nM).
Subject(s)
Obesity/drug therapy , Piperidines/pharmacology , Piperidines/therapeutic use , Pyrrolidines/pharmacology , Pyrrolidines/therapeutic use , Receptors, Somatostatin/antagonists & inhibitors , Binding, Competitive/drug effects , Drug Evaluation, Preclinical , Humans , Molecular Structure , Piperidines/chemistry , Pyrrolidines/chemistry , Stereoisomerism , Structure-Activity RelationshipABSTRACT
An 8,5-fused bicyclic peptidomimetic ring system generated by a stereoselective ring metathesis reaction was elaborated into potent inhibitors of interleukin-1beta converting enzyme (ICE, caspase-1). Multiple compounds were found that exhibited ICE IC50 values < 10 nM and were selective over caspase-3 and caspase-8. These active analogs generally possessed good activity (IC50 values < 100 nM) in a whole cell assay measuring IL-1beta production. Pharmacokinetic analysis of the ethyl acetal prodrug form of a selected active lead revealed a compound with a reasonable plasma half-life (1.1 h) and good oral bioavailability (30%).
Subject(s)
Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Caspase Inhibitors , Peptides, Cyclic/pharmacology , Animals , Biological Availability , Bridged Bicyclo Compounds, Heterocyclic/chemical synthesis , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacokinetics , Enzyme Inhibitors/pharmacology , Half-Life , Inhibitory Concentration 50 , Molecular Mimicry , Peptides, Cyclic/chemical synthesis , Prodrugs/pharmacokinetics , Structure-Activity Relationship , Substrate SpecificityABSTRACT
A novel series of substituted quinoline analogs were designed and synthesized as potent and selective melanin concentrating hormone (MCH) antagonists. These analogs show potent (nM) activity (12a-k) with a moderate selectivity. Conversely, the conformationally constrained thienopyrimidinone analogs (18a-g) showed improved activity in MCH-1R and selectivity over 5HT2C.
Subject(s)
Anti-Obesity Agents/chemical synthesis , Hypothalamic Hormones/antagonists & inhibitors , Melanins/antagonists & inhibitors , Pituitary Hormones/antagonists & inhibitors , Quinolines/chemical synthesis , Quinolines/pharmacology , Anti-Obesity Agents/pharmacology , Drug Design , Humans , Inhibitory Concentration 50 , Ligands , Pyrimidinones , Structure-Activity Relationship , Substrate SpecificityABSTRACT
A series of monocyclic thiazepine inhibitors of interleukin-1beta converting enzyme (ICE) were synthesized in eight steps from commercially available intermediates. In vitro biological evaluation showed the thiazepines to be moderately potent ICE inhibitors, with the most active compound exhibiting an IC50 value of 30 nM in an enzyme inhibition assay. Compounds of this class possessed good selectivity against the related enzymes caspase-3 and caspase-8.
Subject(s)
Caspase Inhibitors , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/pharmacology , Thiazepines/chemical synthesis , Thiazepines/pharmacology , Caspase 1/metabolism , Crystallography, X-Ray , Enzyme Inhibitors/chemistry , Inhibitory Concentration 50 , Models, Molecular , Molecular Structure , Structure-Activity Relationship , Thiazepines/chemistryABSTRACT
The design, synthesis, and structure-activity relationships (SAR) of a series of novel proline and pyrrolidine based melanocortin receptor (MCR) agonists are described. To validate a conformationally constrained Arg-Nal dipeptide analogue strategy, we first synthesized and evaluated a test set of cis-(2R,4R)-proline analogues (21a-g). All of these compounds showed significant binding and agonist potency at the hMC1R, hMC3R, and hMC4R. Potent cis-(2S,4R)-pyrrolidine based MCR agonists (35a-g) were subsequently developed by means of this design approach. A SAR study directed toward probing the effect of the two chiral centers in the pyrrolidine ring on biological activity revealed the importance of the (S) absolute configuration at the 2-position for binding affinity, agonist potency, and receptor selectivity. Among the four sets of the pyrrolidine diastereomers investigated, analogues with the (2S,4R) configuration were the most potent agonists across the three receptors, followed by those possessing the (2S,4S) configuration.
Subject(s)
Dipeptides/chemistry , Proline/analogs & derivatives , Proline/chemical synthesis , Pyrrolidines/chemical synthesis , Receptors, Melanocortin/agonists , Binding, Competitive , Cell Line , Humans , Ligands , Molecular Conformation , Molecular Mimicry , Proline/pharmacology , Pyrrolidines/pharmacology , Stereoisomerism , Structure-Activity RelationshipABSTRACT
Novel 1-(2-acylhydrazinocarbonyl)cycloalkyl carboxamides were designed as peptidomimetic inhibitors of interleukin-1beta converting enzyme (ICE). A short synthesis was developed and moderately potent ICE inhibitors were identified (IC(50) values <100 nM). Most of the synthesized examples were selective for ICE versus the related cysteine proteases caspase-3 and caspase-8, although several dual-acting inhibitors of ICE and caspase-8 were identified. Several of the more potent ICE inhibitors were also shown to inhibit IL-1beta production in a whole cell assay (IC(50) < 500 nM).
Subject(s)
Amides/chemical synthesis , Amides/pharmacology , Aminoimidazole Carboxamide/chemical synthesis , Caspase Inhibitors , Hydrazines/chemical synthesis , Hydrazines/pharmacology , Aminoimidazole Carboxamide/analogs & derivatives , Caspase 8 , Chemistry, Pharmaceutical/methods , Cysteine Endopeptidases/metabolism , Drug Industry/methods , Drug Screening Assays, Antitumor , Enzyme Inhibitors/pharmacology , Humans , Inhibitory Concentration 50 , Models, ChemicalABSTRACT
The design and synthesis of a series of potent 1,3,4-trisubstituted-2-oxopiperazine based MC4 agonists are described. The tripeptidomimetic analogs (12a,b and 23) and the dipeptidomimetic 27 displayed single-nanomolar binding affinity and agonist potency for MC4R and excellent selectivity for MC4R relative to MC1R.
Subject(s)
Drug Design , Guanidines/chemistry , Guanidines/pharmacology , Piperazines/chemistry , Piperazines/pharmacology , Receptor, Melanocortin, Type 4/agonists , Guanidines/chemical synthesis , Molecular Structure , Piperazines/chemical synthesis , Receptor, Melanocortin, Type 4/metabolism , Structure-Activity RelationshipABSTRACT
The first synthesis of Tic-D-Phe Psi[CH(2)-CH(2)] isostere is described, which features diastereoselective alkylation of the tricyclic lactam 14. The use of this novel dipeptide isostere in the development of melanocortin agonists has been demonstrated by the synthesis of peptidomimetic 7 and non-peptidic ligand 27. Both compounds displayed significant binding and agonist potency at the MC4R.
Subject(s)
Dipeptides/chemical synthesis , Dipeptides/metabolism , Phenylalanine/chemistry , Receptor, Melanocortin, Type 4/agonists , Alkylation , Dipeptides/chemistry , Humans , Lactams/chemistry , Ligands , Models, Molecular , Molecular Mimicry , Molecular Structure , Receptor, Melanocortin, Type 3/agonists , Stereoisomerism , Structure-Activity RelationshipABSTRACT
Two novel 8,6-fused bicyclic peptidomimetic ring systems were synthesized utilizing olefin metathesis as the key reaction for the formation of the eight-membered ring. Both peptidomimetic scaffolds were further elaborated into potent ICE inhibitors, with numerous compounds exhibiting caspase-1 IC(50)s less than 10nM.
Subject(s)
Biomimetics , Bridged Bicyclo Compounds, Heterocyclic/pharmacology , Caspase Inhibitors , Enzyme Inhibitors/pharmacology , Bridged Bicyclo Compounds, Heterocyclic/chemical synthesis , Enzyme Inhibitors/chemical synthesis , Humans , Indicators and Reagents , Models, Molecular , Molecular ConformationABSTRACT
A novel diazocan containing dipeptide mimetic was synthesized via reductive N-N bond cleavage of a pyrazolidino-pyrazolidine using Raney-Ni and evaluated as an ICE inhibitor. This versatile 8-membered ring containing scaffold possesses an N-5 ring nitrogen that was used to explore structure-activity relationships in a cell-based assay measuring inhibition of interleukin-1beta.