RESUMO
Agonism of the 5-HT2C receptor represents one of the most well-studied and clinically proven mechanisms for pharmacological weight reduction. Selectivity over the closely related 5-HT2A and 5-HT2B receptors is critical as their activation has been shown to lead to undesirable side effects and major safety concerns. In this communication, we report the development of a new screening paradigm that utilizes an active site mutant D134A (D3.32) 5-HT2C receptor to identify atypical agonist structures. We additionally report the discovery and optimization of a novel class of nonbasic heterocyclic amide agonists of 5-HT2C. SAR investigations around the screening hits provided a diverse set of potent agonists at 5-HT2C with high selectivity over the related 5-HT2A and 5-HT2B receptor subtypes. Further optimization through replacement of the amide with a variety of five- and six-membered heterocycles led to the identification of 6-(1-ethyl-3-(quinolin-8-yl)-1H-pyrazol-5-yl)pyridazin-3-amine (69). Oral administration of 69 to rats reduced food intake in an ad libitum feeding model, which could be completely reversed by a selective 5-HT2C antagonist.
Assuntos
Arginina/análogos & derivados , Flavonas/química , Receptor 5-HT2C de Serotonina/metabolismo , Agonistas do Receptor 5-HT2 de Serotonina/química , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 2 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Animais , Arginina/síntese química , Arginina/química , Arginina/farmacologia , Encéfalo/metabolismo , Células CACO-2 , Permeabilidade da Membrana Celular , Comportamento Alimentar/efeitos dos fármacos , Flavonas/síntese química , Flavonas/farmacologia , Células HEK293 , Humanos , Masculino , Membranas Artificiais , Camundongos Knockout , Microssomos Hepáticos/metabolismo , Mutação , Ratos Sprague-Dawley , Receptor 5-HT2A de Serotonina/metabolismo , Receptor 5-HT2B de Serotonina/metabolismo , Receptor 5-HT2C de Serotonina/genética , Agonistas do Receptor 5-HT2 de Serotonina/síntese química , Agonistas do Receptor 5-HT2 de Serotonina/farmacocinética , Agonistas do Receptor 5-HT2 de Serotonina/farmacologia , Relação Estrutura-AtividadeRESUMO
Insulin-degrading enzyme (IDE, insulysin) is the best characterized catabolic enzyme implicated in proteolysis of insulin. Recently, a peptide inhibitor of IDE has been shown to affect levels of insulin, amylin, and glucagon in vivo. However, IDE(-/-) mice display variable phenotypes relating to fasting plasma insulin levels, glucose tolerance, and insulin sensitivity depending on the cohort and age of animals. Here, we interrogated the importance of IDE-mediated catabolism on insulin clearance in vivo. Using a structure-based design, we linked two newly identified ligands binding at unique IDE exosites together to construct a potent series of novel inhibitors. These compounds do not interact with the catalytic zinc of the protease. Because one of these inhibitors (NTE-1) was determined to have pharmacokinetic properties sufficient to sustain plasma levels >50 times its IDE IC50 value, studies in rodents were conducted. In oral glucose tolerance tests with diet-induced obese mice, NTE-1 treatment improved the glucose excursion. Yet in insulin tolerance tests and euglycemic clamp experiments, NTE-1 did not enhance insulin action or increase plasma insulin levels. Importantly, IDE inhibition with NTE-1 did result in elevated plasma amylin levels, suggesting the in vivo role of IDE action on amylin may be more significant than an effect on insulin. Furthermore, using the inhibitors described in this report, we demonstrate that in HEK cells IDE has little impact on insulin clearance. In total, evidence from our studies supports a minimal role for IDE in insulin metabolism in vivo and suggests IDE may be more important in helping regulate amylin clearance.
Assuntos
Inibidores Enzimáticos/farmacologia , Insulina/metabolismo , Insulisina/antagonistas & inibidores , Animais , Sítios de Ligação , Cristalografia por Raios X , Inibidores Enzimáticos/farmacocinética , Células HEK293 , Humanos , Insulisina/química , Modelos Moleculares , ProteóliseRESUMO
G-protein-coupled receptor 119 (GPR119) is expressed predominantly in pancreatic ß-cells and in enteroendocrine cells in the gastrointestinal tract. GPR119 agonists have been shown to stimulate glucose-dependent insulin release by direct action in the pancreas and to promote secretion of the incretin GLP-1 by action in the gastrointestinal tract. This dual mechanism of action has generated significant interest in the discovery of small molecule GPR119 agonists as a potential new treatment for type 2 diabetes. Herein, we describe the discovery and optimization of a new class of pyridone containing GPR119 agonists. The potent and selective BMS-903452 (42) was efficacious in both acute and chronic in vivo rodent models of diabetes. Dosing of 42 in a single ascending dose study in normal healthy humans showed a dose dependent increase in exposure and a trend toward increased total GLP-1 plasma levels.
Assuntos
Descoberta de Drogas , Hipoglicemiantes/farmacologia , Terapia de Alvo Molecular , Piridonas/farmacologia , Receptores Acoplados a Proteínas G/metabolismo , Sulfonas/farmacologia , Animais , Ensaios Clínicos como Assunto , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/metabolismo , Desenho de Fármacos , Hipoglicemiantes/química , Hipoglicemiantes/farmacocinética , Hipoglicemiantes/uso terapêutico , Masculino , Camundongos , Modelos Moleculares , Conformação Proteica , Piridonas/química , Piridonas/farmacocinética , Piridonas/uso terapêutico , Ratos , Ratos Sprague-Dawley , Receptores Acoplados a Proteínas G/química , Sulfonas/química , Sulfonas/farmacocinética , Sulfonas/uso terapêuticoRESUMO
The 5-HT2C receptor has been implicated as a critical regulator of appetite. Small molecule activation of the 5-HT2C receptor has been shown to affect food intake and regulate body weight gain in rodent models and more recently in human clinical trials. Therefore, 5-HT2C is a well validated target for anti-obesity therapy. The synthesis and structure-activity relationships of a series of novel tetrahydropyrazinoisoquinolinone 5-HT2C receptor agonists are presented. Several members of this series were identified as potent 5-HT2C receptor agonists with high functional selectivity against the 5-HT2A and 5-HT2B receptors and reduced food intake in an acute rat feeding model upon oral dosing.
Assuntos
Isoquinolinas/farmacologia , Pirazinas/farmacologia , Receptor 5-HT2C de Serotonina/metabolismo , Animais , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Ingestão de Alimentos/efeitos dos fármacos , Humanos , Isoquinolinas/síntese química , Isoquinolinas/química , Modelos Moleculares , Estrutura Molecular , Pirazinas/síntese química , Pirazinas/química , Ratos , Relação Estrutura-AtividadeRESUMO
A series of 2,3,3a,4-tetrahydro-1H-pyrrolo[3,4-c]isoquinolin-5(9bH)-ones is described, several examples of which exhibit potent 5-HT(2C) agonism with excellent selectivity over the closely related 5-HT(2A) and 5-HT(2B) receptors. Compounds such as 38 and 44 were shown to be effective in reducing food intake in an acute rat feeding model.
Assuntos
Compostos Heterocíclicos com 3 Anéis/síntese química , Isoquinolinas/química , Pirróis/química , Pirróis/síntese química , Receptor 5-HT2C de Serotonina/química , Agonistas do Receptor 5-HT2 de Serotonina/síntese química , Animais , Meia-Vida , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/farmacocinética , Humanos , Isoquinolinas/síntese química , Isoquinolinas/farmacocinética , Masculino , Pirróis/farmacocinética , Ratos , Ratos Sprague-Dawley , Receptor 5-HT2A de Serotonina/química , Receptor 5-HT2A de Serotonina/metabolismo , Receptor 5-HT2B de Serotonina/química , Receptor 5-HT2B de Serotonina/metabolismo , Receptor 5-HT2C de Serotonina/metabolismo , Agonistas do Receptor 5-HT2 de Serotonina/química , Agonistas do Receptor 5-HT2 de Serotonina/farmacocinética , Relação Estrutura-AtividadeRESUMO
Agonists of the 5-HT(2C) receptor have been shown to suppress appetite and reduce body weight in animal models as well as in humans. However, agonism of the related 5-HT(2B) receptor has been associated with valvular heart disease. Synthesis and biological evaluation of a series of novel and highly selective dihydroquinazolinone-derived 5-HT(2C) agonists with no detectable agonism of the 5-HT(2B) receptor is described. Among these, compounds (+)-2a and (+)-3c were identified as potent and highly selective agonists which exhibited weight loss in a rat model upon oral dosing.
Assuntos
Fármacos Antiobesidade/química , Obesidade/tratamento farmacológico , Quinazolinonas/química , Agonistas do Receptor 5-HT2 de Serotonina , Agonistas do Receptor de Serotonina/química , Administração Oral , Animais , Fármacos Antiobesidade/administração & dosagem , Fármacos Antiobesidade/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Ingestão de Alimentos/fisiologia , Humanos , Masculino , Obesidade/metabolismo , Ligação Proteica/fisiologia , Quinazolinonas/administração & dosagem , Ratos , Ratos Sprague-Dawley , Receptor 5-HT2C de Serotonina/metabolismo , Agonistas do Receptor de Serotonina/administração & dosagem , Agonistas do Receptor de Serotonina/metabolismoRESUMO
Successful development of 5-HT(2C) agonists requires selectivity versus the highly homologous 5-HT(2A) receptor, because agonism at this receptor can result in significant adverse events. (R)-9-Ethyl-1,3,4,10b-tetrahydro-7-trifluoromethylpyrazino[2,1-a]isoindol-6(2H)-one (compound 1) is a potent 5-HT(2C) agonist exhibiting selectivity over the human 5-HT(2A) receptor. Evaluation of the compound at the rat 5-HT(2A) receptor, however, revealed potent binding and agonist functional activity. The physiological consequence of this higher potency was the observation of a significant increase in blood pressure in conscious telemeterized rats that could be prevented by ketanserin. Docking of compound 1 in a homology model of the 5-HT(2A) receptor indicated a possible binding mode in which the ethyl group at the 9-position of the molecule was oriented toward position 5.46 of the 5-HT(2A) receptor. Within the human 5-HT(2A) receptor, position 5.46 is Ser242; however, in the rat 5-HT(2A) receptor, it is Ala242, suggesting that the potent functional activity in this species resulted from the absence of the steric bulk provided by the -OH moiety of the Ser in the human isoform. We confirmed this hypothesis using site-directed mutagenesis through the mutation of both the human receptor Ser242 to Ala and the rat receptor Ala242 to Ser, followed by radioligand binding and second messenger studies. In addition, we attempted to define the space allowed by the alanine by evaluating compounds with larger substitutions at the 9-position. The data indicate that position 5.46 contributed to the species difference in 5-HT(2A) receptor potency observed for a pyrazinoisoindolone compound, resulting in the observation of a significant cardiovascular safety signal.
Assuntos
Isoindóis/farmacologia , Pirazinas/farmacologia , Agonistas do Receptor 5-HT2 de Serotonina , Animais , Ligação Competitiva/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , Cálcio/metabolismo , Linhagem Celular , Cães , Variação Genética , Humanos , Isoindóis/metabolismo , Ketanserina/farmacologia , Macaca fascicularis , Masculino , Atividade Motora/efeitos dos fármacos , Mutagênese Sítio-Dirigida , Ligação Proteica/efeitos dos fármacos , Pirazinas/metabolismo , Ratos , Ratos Sprague-Dawley , Receptor 5-HT2A de Serotonina/efeitos dos fármacos , Receptor 5-HT2A de Serotonina/metabolismo , Receptor 5-HT2C de Serotonina/genética , Receptor 5-HT2C de Serotonina/fisiologia , Homologia de Sequência de Aminoácidos , Antagonistas da Serotonina/farmacologia , Especificidade da Espécie , Homologia Estrutural de ProteínaRESUMO
Robust pharmaceutical treatment of obesity has been limited by the undesirable side-effect profile of currently marketed therapies. This paper describes the synthesis and optimization of a new class of pyrazinoisoindolone-containing, selective 5-HT2C agonists as antiobesity agents. Key to optimization of the pyrazinoisoindolone core was the identification of the appropriate substitution pattern and functional groups which led to the discovery of (R)-9-ethyl-1,3,4,10b-tetrahydro-7-trifluoromethylpyrazino[2,1-a]isoindol-6(2H)-one (58), a 5-HT2C agonist with >300-fold functional selectivity over 5-HT2B and >70-fold functional selectivity over 5-HT2A. Oral dosing of 58 reduced food intake in an acute rat feeding model, which could be completely reversed by a selective 5-HT2C antagonist and caused a reduction in body weight gain in a 4-day rat model.