RESUMO
A novel series of annulated tricyclic compounds was synthesized and evaluated as NMDA/NR2B antagonists. Structure-activity development was directed towards in vitro optimization of NR2B activity and selectivity over the hERG K(+) channel. Preferred compounds were subsequently evaluated for selectivity in an alpha(1)-adrenergic receptor binding counter-screen and a cell-based assay of NR2B activity.
Assuntos
Benzocicloeptenos/síntese química , Neurotransmissores/síntese química , Piridinas/síntese química , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Benzocicloeptenos/química , Benzocicloeptenos/farmacologia , Linhagem Celular , Canais de Potássio Éter-A-Go-Go/metabolismo , Humanos , Neurotransmissores/química , Neurotransmissores/farmacologia , Piridinas/química , Piridinas/farmacologia , Receptores de N-Metil-D-Aspartato/metabolismo , Relação Estrutura-AtividadeRESUMO
Peptidomimetic research is an approach to identify peptide-based drugs designed to mimic structural, conformational, and biological properties of peptides while overcoming their limitations, such as protease instability and poor cell penetration. With recent advances in ribosomal synthesis of peptides containing unnatural amino acids, this technology appears suitable for preparing large structurally diverse libraries of peptidomimetics for drug discovery screening.
RESUMO
Selective bradykinin (BK) B 1 receptor antagonists could be novel therapeutic agents for the treatment of pain and inflammation. Elucidation of the structure activity relationships of the structurally novel HTS lead compound 1 provided potent hBK B 1 receptor antagonists with excellent receptor occupancy in the CNS of hBK B 1 transgenic rats.
Assuntos
Aminas/química , Benzofenonas/química , Benzofenonas/farmacologia , Antagonistas de Receptor B1 da Bradicinina , Animais , Benzofenonas/síntese química , Linhagem Celular , Cães , Humanos , Estrutura Molecular , Ratos , Receptor B1 da Bradicinina/metabolismo , Relação Estrutura-AtividadeRESUMO
Antagonism of the bradykinin B(1) receptor represents a potential treatment for chronic pain and inflammation. Novel antagonists incorporating alpha-hydroxy amides were designed that display low-nanomolar affinity for the human bradykinin B(1) receptor and good bioavailability in the rat and dog. In addition, these functionally active compounds show high passive permeability and low susceptibility to phosphoglycoprotein mediated efflux, predictive of good CNS exposure.
Assuntos
Amidas/farmacologia , Antagonistas de Receptor B1 da Bradicinina , Amidas/química , Amidas/farmacocinética , Animais , Disponibilidade Biológica , Barreira Hematoencefálica , Inibidores das Enzimas do Citocromo P-450 , Cães , Meia-Vida , Humanos , Ratos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
Selective bradykinin (BK) B(1) receptor antagonists have been shown to be antinociceptive in animal models and could be novel therapeutic agents for the treatment of pain and inflammation. Elucidation of the structure-activity relationships of the biphenyl moiety of the lead compound 1 provided a potent new structural class of BK B(1) receptor antagonists.
Assuntos
Analgésicos/química , Anti-Inflamatórios não Esteroides/química , Antagonistas de Receptor B1 da Bradicinina , Cicloexanos/química , Hidrocarbonetos Fluorados/química , Piridinas/química , Analgésicos/síntese química , Analgésicos/farmacologia , Animais , Animais Geneticamente Modificados , Anti-Inflamatórios não Esteroides/síntese química , Anti-Inflamatórios não Esteroides/farmacologia , Cicloexanos/síntese química , Cicloexanos/farmacologia , Humanos , Hidrocarbonetos Fluorados/síntese química , Hidrocarbonetos Fluorados/farmacologia , Piridinas/síntese química , Piridinas/farmacologia , Ratos , Receptor B1 da Bradicinina/genética , Relação Estrutura-AtividadeRESUMO
Antagonism of the bradykinin B1 receptor represents a potential treatment for chronic pain and inflammation. Novel antagonists were designed that display low-nanomolar affinity for the human bradykinin B1 receptor and good bioavailability in the rat.
Assuntos
Amidas/síntese química , Analgésicos/síntese química , Anti-Inflamatórios não Esteroides/síntese química , Antagonistas de Receptor B1 da Bradicinina , Ciclopropanos/síntese química , Piridinas/síntese química , Amidas/química , Amidas/farmacologia , Analgésicos/química , Analgésicos/farmacologia , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Disponibilidade Biológica , Ciclopropanos/química , Ciclopropanos/farmacologia , Desenho de Fármacos , Humanos , Conformação Molecular , Piridinas/química , Piridinas/farmacologia , Ratos , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
SAR study of the biphenyl region of 2,3-diaminopyridine bradykinin B1 antagonists was investigated with non-aromatic carbo- and heterocyclic rings. A piperidine ring was found to be a good replacement for the proximal phenyl ring while replacement of the distal phenyl was optimal with a cyclohexyl group leading to a dramatic improvement in affinity for the B1 receptor.
Assuntos
Aminopiridinas/síntese química , Antagonistas de Receptor B1 da Bradicinina , Aminopiridinas/farmacocinética , Aminopiridinas/farmacologia , Animais , Bradicinina/antagonistas & inibidores , Humanos , Farmacocinética , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
We report the first homology model of human bradykinin receptor B1 generated from the crystal structure of bovine rhodopsin as a template. Using an automated docking procedure, two B1 receptor antagonists of the dihydroquinoxalinone structural class were docked into the receptor model. Site-directed mutagenesis data of the amino acid residues in TM1, TM3, TM6, and TM7 were incorporated to place the compounds in the binding site of the homology model of the human B1 bradykinin receptor. The best pose in agreement with the mutation data was selected for detailed study of the receptor-antagonist interaction. To test the model, the calculated antagonist-receptor binding energy was correlated with the experimentally measured binding affinity (K(i)) for nine dihydroquinoxalinone analogs. The model was used to gain insight into the molecular mechanism for receptor function and to optimize the dihydroquinoxalinone analogs.
Assuntos
Modelos Moleculares , Quinoxalinas/química , Receptor B1 da Bradicinina/química , Sequência de Aminoácidos , Sítios de Ligação , Humanos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Ligação Proteica , Estrutura Secundária de Proteína , Receptor B1 da Bradicinina/genética , Receptor B1 da Bradicinina/metabolismo , Rodopsina/química , Alinhamento de Sequência , Homologia Estrutural de ProteínaRESUMO
A novel class of 2,3-diaminopyridine bradykinin B1 receptor antagonists is disclosed. Structure-activity relationship studies (SARs) that led to compounds with significantly improved potency and pharmacokinetic properties relative to the lead compound are described.
Assuntos
Aminopiridinas/farmacologia , Antagonistas de Receptor B1 da Bradicinina , Piridinas/síntese química , Aminopiridinas/química , Desenho de Fármacos , Humanos , Cinética , Modelos Moleculares , Piridinas/farmacologia , Relação Estrutura-AtividadeRESUMO
Bradykinin B1 receptor antagonists embody a potentially novel approach for the treatment of chronic pain and inflammation. A series of 2,3-diaminopyridine B1 antagonists was optimized to have sub-nanomolar affinity and good pharmacokinetic properties. Lead compounds were shown to exhibit good efficacy in rabbit in vivo models of pain and inflammation.
Assuntos
Aminopiridinas/síntese química , Analgésicos/síntese química , Anti-Inflamatórios não Esteroides/síntese química , Antagonistas de Receptor B1 da Bradicinina , Aminopiridinas/química , Aminopiridinas/farmacologia , Analgésicos/química , Analgésicos/farmacologia , Animais , Anti-Inflamatórios não Esteroides/química , Anti-Inflamatórios não Esteroides/farmacologia , Cães , Meia-Vida , Inflamação/tratamento farmacológico , Medição da Dor , Coelhos , Ratos , Especificidade da Espécie , Relação Estrutura-AtividadeRESUMO
We have developed an efficient and selective radioligand, the [35S]-radiolabeled dihydroquinoxalinone derivative, 4, for an ex vivo receptor occupancy assay in transgenic rats over-expressing the human bradykinin B1 receptor.
Assuntos
Antagonistas de Receptor B1 da Bradicinina , Quinoxalinas/síntese química , Quinoxalinas/farmacologia , Animais , Animais Geneticamente Modificados , Ligação Competitiva/efeitos dos fármacos , Humanos , Marcação por Isótopo , Ligantes , Ensaio Radioligante , Ratos , Receptor B1 da Bradicinina/química , Relação Estrutura-Atividade , Radioisótopos de EnxofreRESUMO
Compound A (N-[2-[4-(4,5-dihydro-1H-imidazol-2-yl)phenyl]ethyl]-2-[(2R)-1-(2-napthylsulfonyl)-3-oxo-1,2,3,4-tetrahydroquinoxalin-2-yl]acetamide) is a member of a new class of aryl sulfonamide dihydroquinoxalinone bradykinin B1 receptor antagonists that should be useful pharmacological tools. Here we report on some of the pharmacological properties of compound A as well as the characterization of [35S]compound A as the first nonpeptide bradykinin B1 receptor radioligand. Compound A inhibited tritiated peptide ligand binding to the cloned human, rabbit, dog, and rat bradykinin B1 receptors expressed in CHO cells with Ki values of 0.016, 0.050, 0.56, and 29 nM, respectively. It was inactive at 10 microM in binding assays with the cloned human bradykinin B2 receptor. In functional antagonist assays with the cloned bradykinin B1 receptors, compound A inhibited agonist-induced signaling with activities consistent with the competition binding results, but had no antagonist activity at the bradykinin B2 receptor. Compound A was also found to be a potent antagonist in a rabbit aorta tissue bath preparation and to effectively block des-Arg9 bradykinin depressor responses in lipopolysaccharide-treated rabbit following intravenous administration. The binding of [35S]compound A was evaluated with the cloned bradykinin B1 receptors. In assays with human, rabbit, and dog receptors, [35S]compound A labeled a single site with Kd values of 0.012, 0.064, and 0.37 nM, respectively, and with binding site densities equivalent to those obtained using the conventional tritiated peptide ligands. Binding assays with the cloned rat bradykinin B1 receptor were not successful, presumably due to the low affinity of the ligand for this species receptor. There was no specific binding of the ligand detected in CHO cells expressing the human bradykinin B2 receptor. In assays with the cloned human bradykinin B1 receptor, the pharmacologies of the binding of [35S]compound A and [3H][Leu9]des-Arg10-kallidin were the same. The high signal-to-noise ratio obtained with [35S]compound A will allow this ligand to be a very useful tool for future investigations of the bradykinin B1 receptor.
Assuntos
Antagonistas de Receptor B1 da Bradicinina , Calidina/análogos & derivados , Receptor B1 da Bradicinina/metabolismo , Animais , Aorta Torácica/efeitos dos fármacos , Aorta Torácica/fisiologia , Ligação Competitiva/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Células CHO , Cricetinae , Cricetulus , Cães , Relação Dose-Resposta a Droga , Humanos , Imidazóis/metabolismo , Imidazóis/farmacologia , Técnicas In Vitro , Calidina/metabolismo , Lipopolissacarídeos/farmacologia , Masculino , Quinoxalinas/metabolismo , Quinoxalinas/farmacologia , Coelhos , Ensaio Radioligante , Ratos , Receptor B1 da Bradicinina/genética , Transfecção , Trítio , Vasoconstrição/efeitos dos fármacosRESUMO
The HIV-1 gp41 envelope glycoprotein mediates fusion of the viral and cellular membranes. The core of the gp41 ectodomain undergoes a receptor-triggered conformational transition forming a trimeric, alpha-helical coiled-coil structure. This trimer-of-hairpins species facilitates insertion of the viral envelope protein into the host cell membrane promoting viral entry. The prefusogenic conformation of gp41 is capable of stimulating a neutralizing antibody immune response and is therefore an attractive therapeutic target. Several broadly neutralizing HIV-1 monoclonal antibodies which bind to gp41 have been characterized and include 4E10, Z13 and 2F5. A conserved segment of gp41 (residues 661-684) has been identified as the epitope for the HIV-1 neutralizing antibody 2F5 (MAb 2F5). MAb 2F5 has attracted considerable attention because of the highly conserved recognition epitope and the ability to neutralize both laboratory-adapted and primary viral isolates. Antibodies which recognize the immunodominant regions of gp41 may provide protection against HIV infection if elicited at appropriate concentrations. Here we review the rational design, structure-activity relationships and conformational features of both linear and constrained peptide immunogens incorporating variants of both the 2F5 epitope and the gp41 ectodomain. This review describes a rational design approach combining structural characterization with traditional SAR to optimize MAb 2F5 antibody affinities of gp41-based peptide immunogens. The immunogens are shown to stimulate a high titer, peptide-specific immune response; however, the resulting antisera were incapable of viral neutralization. The implication of these findings with regard to structural and immunological considerations is discussed.
Assuntos
Vacinas contra a AIDS , Proteína gp41 do Envelope de HIV/imunologia , Vacinas contra a AIDS/imunologia , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Sequência Conservada , Desenho de Fármacos , Epitopos/genética , Epitopos/imunologia , Anticorpos Anti-HIV/imunologia , Proteína gp41 do Envelope de HIV/química , Humanos , Dados de Sequência Molecular , Testes de Neutralização , Conformação Proteica , Estrutura Secundária de Proteína , Vacinas de Subunidades Antigênicas/imunologiaRESUMO
Two classes of 5-substituted benzimidazoles were identified as potent antagonists of the NR2B subtype of the N-methyl-d-aspartate (NMDA) receptor. Selected compounds show very good selectivity versus the NR2A, NR2C, and NR2D subtypes of the NMDA receptor as well as versus hERG-channel activity and alpha(1)-adrenergic binding. Benzimidazole 37a shows excellent activity in the carrageenan-induced mechanical hyperalgesia assay in rats as well as good pharmacokinetic behavior in dogs.
Assuntos
Analgésicos/síntese química , Benzimidazóis/síntese química , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Analgésicos/farmacocinética , Analgésicos/farmacologia , Animais , Benzimidazóis/farmacocinética , Benzimidazóis/farmacologia , Encéfalo/metabolismo , Cálcio/metabolismo , Carragenina , Linhagem Celular , Cães , Feminino , Humanos , Hiperalgesia/sangue , Hiperalgesia/induzido quimicamente , Hiperalgesia/tratamento farmacológico , Técnicas In Vitro , Masculino , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley , Receptores de N-Metil-D-Aspartato/fisiologia , Relação Estrutura-AtividadeAssuntos
Lactamas/síntese química , Peptídeos/química , Animais , Antineoplásicos/síntese química , Antineoplásicos/química , Antineoplásicos/farmacologia , Dipeptídeos/síntese química , Dipeptídeos/química , Dipeptídeos/farmacologia , Doxorrubicina/química , Desenho de Fármacos , Humanos , Lactamas/química , Lactamas/farmacologia , Conformação Molecular , Mimetismo Molecular , Peptídeos Cíclicos/síntese química , Peptídeos Cíclicos/química , Peptídeos Cíclicos/farmacologia , Antígeno Prostático Específico/metabolismo , Somatostatina/agonistas , Vimblastina/químicaRESUMO
Bradykinin (BK) plays an important role in the pathophysiological processes accompanying pain and inflammation. Selective bradykinin B1 receptor antagonists have been shown to be anti-nociceptive in animal models and could be novel therapeutic agents for the treatment of pain and inflammation. We have explored chemical modifications in a series of dihydroquinoxalinone sulfonamides to evaluate the effects of various structural changes on biological activity. The optimization of a screening lead compound, facilitated by a homology model of the BK B1 receptor, culminated in the discovery of a potent human BK B1 receptor antagonist. Results from site-directed mutagenesis studies and experiments in an animal pain model are presented.
Assuntos
Antagonistas dos Receptores da Bradicinina , Quinoxalinas/química , Quinoxalinas/farmacologia , Analgésicos/química , Analgésicos/farmacologia , Animais , Sítios de Ligação , Cães , Humanos , Cinética , Modelos Moleculares , Mutagênese Sítio-Dirigida , Medição da Dor/efeitos dos fármacos , Coelhos , Ratos , Receptor B1 da Bradicinina , Receptores da Bradicinina/química , Receptores da Bradicinina/genética , Receptores da Bradicinina/metabolismo , Relação Estrutura-AtividadeRESUMO
Antagonism of the bradykinin B(1) receptor was demonstrated to be a potential treatment for chronic pain and inflammation. Novel benzodiazepines were designed that display subnanomolar affinity for the bradykinin B(1) receptor (K(i) = 0.59 nM) and high selectivity against the bradykinin B(2) receptor (K(i) > 10 microM). In vivo efficacy, comparable to morphine, was demonstrated for lead compounds in a rodent hyperalgesia model.
Assuntos
Benzodiazepinas/síntese química , Antagonistas dos Receptores da Bradicinina , Animais , Benzodiazepinas/química , Benzodiazepinas/farmacologia , Células CHO , Cricetinae , Humanos , Hiperalgesia/induzido quimicamente , Hiperalgesia/tratamento farmacológico , Ensaio Radioligante , Ratos , Ratos Sprague-Dawley , Receptor B1 da Bradicinina , Receptor B2 da Bradicinina , Relação Estrutura-AtividadeRESUMO
The search for small-molecule drugs that act at peptide hormone receptors has resulted in the identification of a wide variety of antagonists. In contrast, the discovery of nonpeptide agonists has been far more elusive. We have used a constitutively active mutant of the cholecystokinin 2 receptor (CCK-2R) as a sensitive screen to detect ligand activity. Functional assessment of structural analogs of the prototype CCK-2R antagonist, L-365,260 [3R-N- (2,3-dihydro-1-methyl-2-oxo-5-phenyl-1H-1,4-benzodiazepin-3-yl)-N'-(3-methylphenyl)urea], resulted in the identification of a series of agonists. Each of the active molecules is an S enantiomer, whereas the corresponding R stereoisomers have little or no activity. Further in vitro and in vivo assessment at the wild-type receptor indicated that efficacy of the two most active ligands approached that of the endogenous hormone. The function of selected R and S enantiomers was differentially sensitive to a point mutation, N353L, within the putative CCK-2R ligand pocket. The results of this study highlight the potential of constitutively active receptors as drug screening tools and the interdependence of ligand stereochemistry and receptor conformation in defining drug efficacy.
Assuntos
Benzodiazepinonas/farmacologia , Compostos de Fenilureia/farmacologia , Mutação Puntual , Receptores da Colecistocinina/agonistas , Animais , Benzodiazepinonas/química , Células COS , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Compostos de Fenilureia/química , Receptor de Colecistocinina B , Receptores da Colecistocinina/antagonistas & inibidores , Proteínas Recombinantes/agonistas , Proteínas Recombinantes/antagonistas & inibidores , EstereoisomerismoRESUMO
A novel series of benzamidines was synthesized and shown to exhibit NR2B-subtype selective NMDA antagonist activity. Compound 31 is orally active in a carrageenan-induced rat hyperalgesia model of pain and shows no motor coordination side effects.
Assuntos
Benzamidinas/farmacologia , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Administração Oral , Animais , Benzamidinas/síntese química , Carragenina , Avaliação Pré-Clínica de Medicamentos , Hiperalgesia/tratamento farmacológico , Dor/tratamento farmacológico , Desempenho Psicomotor/efeitos dos fármacos , Ratos , Relação Estrutura-AtividadeRESUMO
Novel 5-cyclopropyl-1,4-benzodiazepin-2-ones having various N-l substituents were identified as potent and selective blockers of the slowly activating cardiac delayed rectifier potassium current (I(Ks)). Compound 11 is the most potent I(Ks) channel blocker reported to date.