RESUMO
In an ongoing effort to explore the use of orexin receptor antagonists for the treatment of insomnia, dual orexin receptor antagonists (DORAs) were structurally modified, resulting in compounds selective for the OX2R subtype and culminating in the discovery of 23, a highly potent, OX2R-selective molecule that exhibited a promising in vivo profile. Further structural modification led to an unexpected restoration of OX1R antagonism. Herein, these changes are discussed and a rationale for selectivity based on computational modeling is proposed.
Assuntos
Antagonistas dos Receptores de Orexina/farmacologia , Orexinas/antagonistas & inibidores , Animais , Eletroencefalografia , Eletromiografia , Estrutura Molecular , Antagonistas dos Receptores de Orexina/química , RatosRESUMO
While a correlation between blockade of the orexin 2 receptor (OX2R) with either a dual orexin receptor antagonist (DORA) or a selective orexin 2 receptor antagonist (2-SORA) and a decrease of wakefulness is well established, less is known about selective blockade of the orexin 1 receptor (OX1R). Therefore, a highly selective orexin 1 antagonist (1-SORA) with suitable properties to allow in vivo interrogation of OX1R specific pharmacology in preclinical species remains an attractive target. Herein, we describe the discovery of an optimized 1-SORA series in the piperidine ether class. Notably, a 4,4-difluoropiperidine core coupled with a 2-quinoline ether linkage provides OX1R selective compounds. The combination with an azabenzimidazole or imidazopyridine amide substituent leads to analogs 47 and 51 with >625-fold functional selectivity for OX1R over OX2R in rat. Compounds 47 and 51 possess clean off-target profiles and the required pharmacokinetic and physical properties to be useful as 1-SORA tool compounds.
Assuntos
Antagonistas dos Receptores de Orexina/química , Antagonistas dos Receptores de Orexina/farmacologia , Receptores de Orexina/metabolismo , Piperidinas/química , Piperidinas/farmacologia , Animais , Descoberta de Drogas , Humanos , Piperidinas/farmacocinética , Ratos , Ratos Transgênicos , Relação Estrutura-AtividadeRESUMO
Antagonism of orexin receptors has shown clinical efficacy as a novel paradigm for the treatment of insomnia and related disorders. Herein, molecules related to the dual orexin receptor antagonist filorexant were transformed into compounds that were selective for the OX2R subtype. Judicious selection of the substituents on the pyridine ring and benzamide groups led to 6b; which was highly potent, OX2R selective, and exhibited excellent development properties.
Assuntos
Antagonistas dos Receptores de Orexina/química , Receptores de Orexina/química , Piperidinas/química , Triazóis/química , Animais , Cães , Meia-Vida , Camundongos , Antagonistas dos Receptores de Orexina/farmacocinética , Antagonistas dos Receptores de Orexina/uso terapêutico , Receptores de Orexina/metabolismo , Piperidinas/farmacocinética , Piperidinas/uso terapêutico , Ligação Proteica , Pirimidinas/química , Ratos , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Distúrbios do Início e da Manutenção do Sono/veterinária , Relação Estrutura-Atividade , Triazóis/farmacocinética , Triazóis/uso terapêuticoRESUMO
Highly selective orexin receptor antagonists (SORAs) of the orexin 2 receptor (OX2R) have become attractive targets both as potential therapeutics for insomnia as well as biological tools to help further elucidate the underlying pharmacology of the orexin signaling pathway. Herein, we describe the discovery of a novel piperidine ether 2-SORA class identified by systematic lead optimization beginning with filorexant, a dual orexin receptor antagonist (DORA) that recently completed Phase 2 clinical trials. Changes to the ether linkage and pendant heterocycle of filorexant were found to impart significant selectivity for OX2R, culminating in lead compound PE-6. PE-6 displays sub-nanomolar binding affinity and functional potency on OX2R while maintaining >1600-fold binding selectivity and >200-fold functional selectivity versus the orexin 1 receptor (OX1R). PE-6 bears a clean off-target profile, a good overall preclinical pharmacokinetic (PK) profile, and reduces wakefulness with increased NREM and REM sleep when evaluated in vivo in a rat sleep study. Importantly, subtle structural changes to the piperidine ether class impart dramatic changes in receptor selectivity. To this end, our laboratories have identified multiple piperidine ether 2-SORAs, 1-SORAs, and DORAs, providing access to a number of important biological tool compounds from a single structural class.
Assuntos
Éteres/química , Antagonistas dos Receptores de Orexina , Piperidinas/química , Pirimidinas/química , Animais , Cães , Avaliação Pré-Clínica de Medicamentos , Éteres/síntese química , Éteres/farmacocinética , Meia-Vida , Humanos , Receptores de Orexina/metabolismo , Piperidinas/metabolismo , Ligação Proteica , Pirimidinas/metabolismo , Ratos , Sono/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
In our efforts to develop CGRP receptor antagonists as backups to MK-3207, 2, we employed a scaffold hopping approach to identify a series of novel oxazolidinone-based compounds. The development of a structurally diverse, potent (20, cAMP+HS IC50=0.67 nM), and selective compound (hERG IC50=19 µM) with favorable rodent pharmacokinetics (F=100%, t1/2=7h) is described. Key to this development was identification of a 3-substituted spirotetrahydropyran ring that afforded a substantial gain in potency (10 to 35-fold).
Assuntos
Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Transtornos de Enxaqueca/tratamento farmacológico , Oxazolidinonas/farmacologia , Oxazolidinonas/uso terapêutico , Animais , Relação Dose-Resposta a Droga , Humanos , Simulação de Acoplamento Molecular , Estrutura Molecular , Oxazolidinonas/síntese química , Oxazolidinonas/química , Ratos , Relação Estrutura-AtividadeRESUMO
Earlier, we had demonstrated that treatment with low dose of GM-CSF can prevent the development of experimental autoimmune thyroiditis (EAT), experimental autoimmune myasthenia gravis, and type 1 diabetes, and could also reverse ongoing EAT and experimental autoimmune myasthenia gravis. The protective effect was mediated through the induction of tolerogenic CD11C(+)CD8α(-) dendritic cells (DCs) and consequent expansion of Foxp3(+) regulatory T cells (Tregs). Subsequently, we showed that GM-CSF acted specifically on bone marrow precursors and facilitated their differentiation into tolerogenic dendritic cells (DCs; GM-CSF-induced bone marrow-derived DCs [GM-BMDCs]), which directed Treg expansion in a contact-dependent manner. This novel mechanism of Treg expansion was independent of TCR-mediated signaling but required exogenous IL-2 and cosignaling from DC-bound OX40L. In this study, we observed that OX40L-mediated signaling by GM-BMDCs, although necessary, was not sufficient for Treg expansion and required signaling by Jagged1. Concurrent signaling induced by OX40L and Jagged1 via OX40 and Notch3 receptors expressed on Tregs was essential for the Treg expansion with sustained FoxP3 expression. Adoptive transfer of only OX40L(+)Jagged1(+) BMDCs led to Treg expansion, increased production of IL-4 and IL-10, and suppression of EAT in the recipient mice. These results showed a critical role for OX40L- and Jagged1-induced cosignaling in GM-BMDC-induced Treg expansion.
Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Células Dendríticas/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Proteínas de Membrana/metabolismo , Ligante OX40/metabolismo , Transdução de Sinais , Linfócitos T Reguladores/citologia , Linfócitos T Reguladores/imunologia , Animais , Antígenos B7/imunologia , Antígenos B7/metabolismo , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Membrana Celular/imunologia , Membrana Celular/metabolismo , Células Dendríticas/efeitos dos fármacos , Modelos Animais de Doenças , Fatores de Transcrição Forkhead/metabolismo , Fator Estimulador de Colônias de Granulócitos e Macrófagos/farmacologia , Proteína Jagged-1 , Ligantes , Ativação Linfocitária , Camundongos , Receptores Notch/metabolismo , Proteínas Serrate-Jagged , Tireoidite Autoimune/imunologia , Tireoidite Autoimune/metabolismoRESUMO
Analogs of the dual orexin receptor antagonist filorexant were prepared. Replacement of the ether linkage proved highly sensitive toward modification with an acetylene linkage providing compounds with the best in vitro and in vivo potency profiles.
Assuntos
Acetileno/química , Antagonistas dos Receptores de Orexina , Piperidinas/farmacologia , Pirimidinas/farmacologia , Animais , Relação Dose-Resposta a Droga , Camundongos , Camundongos Knockout , Estrutura Molecular , Receptores de Orexina/deficiência , Receptores de Orexina/metabolismo , Piperidinas/síntese química , Piperidinas/química , Pirimidinas/síntese química , Pirimidinas/química , Relação Estrutura-AtividadeRESUMO
Orexin receptor antagonists have demonstrated clinical utility for the treatment of insomnia. The majority of clinical efforts to date have focused on the development of dual orexin receptor antagonists (DORAs), small molecules that antagonize both the orexin 1 and orexin 2 receptors. Our group has recently disclosed medicinal chemistry efforts to identify highly potent, orally bioavailable selective orexin 2 receptor antagonists (2-SORAs) that possess acceptable profiles for clinical development. Herein we report additional SAR studies within the 'triaryl' amide 2-SORA series focused on improvements in compound stability in acidic media and time-dependent inhibition of CYP3A4. These studies resulted in the discovery of 2,5-disubstituted isonicotinamide 2-SORAs such as compound 24 that demonstrated improved stability and TDI profiles as well as excellent sleep efficacy across species.
Assuntos
Descoberta de Drogas , Antagonistas dos Receptores de Orexina , Piridinas/farmacologia , Distúrbios do Início e da Manutenção do Sono/tratamento farmacológico , Tiazóis/farmacologia , Animais , Cães , Relação Dose-Resposta a Droga , Humanos , Camundongos , Estrutura Molecular , Piridinas/síntese química , Piridinas/química , Ratos , Relação Estrutura-Atividade , Tiazóis/síntese química , Tiazóis/químicaRESUMO
The orexin (or hypocretin) system has been identified as a novel target for the treatment of insomnia due to the wealth of biological and genetic data discovered over the past decade. Recently, clinical proof-of-concept was achieved for the treatment of primary insomnia using dual (OX1R/OX2R) orexin receptor antagonists. However, elucidation of the pharmacology associated with selective orexin-2 receptor antagonists (2-SORAs) has been hampered by the lack of orally bioavailable, highly selective small molecule probes. Herein, the discovery and optimization of a novel series of 2,5-diarylnicotinamides as potent and orally bioavailable orexin-2 receptor selective antagonists is described. A compound from this series demonstrated potent sleep promotion when dosed orally to EEG telemetrized rats.
Assuntos
Ácidos Nicotínicos/química , Ácidos Nicotínicos/farmacologia , Antagonistas dos Receptores de Orexina , Animais , Cães , Avaliação Pré-Clínica de Medicamentos , Meia-Vida , Humanos , Ácidos Nicotínicos/síntese química , Ácidos Nicotínicos/farmacocinética , Receptores de Orexina/metabolismo , Ligação Proteica/efeitos dos fármacos , Ratos , Relação Estrutura-AtividadeRESUMO
Rational modification of the clinically tested CGRP receptor antagonist MK-3207 (3) afforded an analogue with increased unbound fraction in rat plasma and enhanced aqueous solubility, 2-[(8R)-8-(3,5-difluorophenyl)-8-methyl-10-oxo-6,9-diazaspiro[4.5]dec-9-yl]-N-[(6S)-2'-oxo-1',2',5,7-tetrahydrospiro[cyclopenta[b]pyridine-6,3'-pyrrolo[2,3-b]pyridin]-3-yl]acetamide (MK-8825) (6). Compound 6 maintained similar affinity to 3 at the human and rat CGRP receptors but possessed significantly improved in vivo potency in a rat pharmacodynamic model. The overall profile of 6 indicates it should find utility as a rat tool to investigate effects of CGRP receptor blockade in vivo.
Assuntos
Analgésicos/síntese química , Analgésicos/farmacologia , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Transtornos de Enxaqueca/tratamento farmacológico , Piridinas/síntese química , Piridinas/farmacologia , Compostos de Espiro/síntese química , Compostos de Espiro/farmacologia , Administração Oral , Analgésicos/sangue , Animais , Disponibilidade Biológica , Modelos Animais de Doenças , Cães , Humanos , Macaca mulatta , Camundongos , Piridinas/sangue , Ratos , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/metabolismo , Especificidade da Espécie , Compostos de Espiro/sangueRESUMO
Background: Performing colonoscopy within 24 h of presentation to the hospital is the accepted standard of care for patients with an acute lower gastrointestinal bleed (LGIB). Previous studies have failed to demonstrate the benefit of early colonoscopy (EC) on mortality. In this study, we wanted to see if there was a change in inpatient deaths (primary outcome), length of stay (LOS), and hospitalization charges (TOTCHG) (secondary outcomes) with EC compared to previous studies. Methods: Adults diagnosed with LGIB were identified using the International Classification of Disease 10th Revision codes from the National Inpatient Sample database for 2016 to 2019. EC was defined as the procedure performed within 24 h of hospitalization. Delayed colonoscopy (DC) was defined as a procedure performed after 24 h of presentation. The patient population was divided into EC and DC groups, and the effects of several covariates on outcomes were measured using binary logistic and multivariate regression analysis. Inverse probability treatment weighting (IPTW) was performed to adjust for confounding covariates. Results: There were 1,549,065 cases diagnosed with LGIB, of which 285,165 cases (18.4%) received a colonoscopy. A total of 107,045 (6.9%) patients received early colonoscopies. EC was associated with decreased inpatient deaths (0.9% in EC, and 1.4% in DC, P < 0.001). However, upon IPTW, this difference was not present. EC was associated with a decreased LOS (median 3 days vs. 5 days, P < 0.001) and TOTCHG (median $32,037 vs. $44,092, P < 0.001). Weekend admissions (WA) were associated with fewer EC (31.6% in WA, and 39.5% in non-WA, P < 0.001). WA did not affect inpatient deaths. Conclusions: EC was not associated with decreased inpatient deaths. There was no difference in endoscopic interventions in both EC and DC groups. The difference in inpatient deaths observed between the two groups was not evident upon adjusting the results for confounders. EC was associated with a decreased LOS, and TOTCHG in patients with LGIB.
RESUMO
Listeria monocytogenes secretes two chitinases and one chitin binding protein. Mutants lacking chiA, chiB, or lmo2467 exhibited normal growth in cultured cells but were defective for growth in the livers and spleens of mice. Mammals lack chitin; thus, L. monocytogenes may have adapted chitinases to recognize alternative substrates to enhance pathogenesis.
Assuntos
Quitinases/fisiologia , Listeria monocytogenes/patogenicidade , Animais , Células CACO-2/microbiologia , Quitina/metabolismo , Quitinases/genética , Quitinases/metabolismo , Genes Bacterianos/genética , Humanos , Listeria monocytogenes/enzimologia , Listeria monocytogenes/genética , Listeriose/microbiologia , Fígado/microbiologia , Camundongos , Baço/microbiologiaRESUMO
A previously utilized quinoline-for-N-phenylamide replacement strategy was employed against a central amide in a novel class of CGRP receptor antagonists. A unique and unexpected substitution pattern was ultimately required to maintain reasonable affinity for the CGRP receptor, while at the same time predicting acceptable heterocycle positioning for related analogs. Subsequently, specific quinoline and naphthyridine compounds were prepared which supported these structural predictions by displaying CGRP binding affinities in the 0.037-0.15 nM range.
Assuntos
Amidas/farmacologia , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Amidas/química , EstereoisomerismoRESUMO
Synthesis of 2-adamantyl carbamate derivatives of piperidines and pyrrolidines led to the discovery of 9a with an IC(50) of 15.2 nM against human 11ß-HSD1 in adipocytes. Optimization for increased adipocyte potency, metabolic stability and selectivity afforded 11k and 11l, both of which were >25% orally bioavailable in rat.
Assuntos
11-beta-Hidroxiesteroide Desidrogenase Tipo 1/antagonistas & inibidores , Adamantano/farmacologia , Inibidores Enzimáticos/farmacologia , Adamantano/química , Animais , Descoberta de Drogas , Inibidores Enzimáticos/química , Modelos Moleculares , RatosRESUMO
Structure-guided drug design led to the identification of a class of spirocyclic ureas which potently inhibit human 11beta-HSD1 in vitro. Lead compound 10j was shown to be orally bioavailable in three species, distributed into adipose tissue in the mouse, and its (R) isomer 10j2 was efficacious in a primate pharmacodynamic model.
Assuntos
11-beta-Hidroxiesteroide Desidrogenase Tipo 1/antagonistas & inibidores , Desenho de Fármacos , Ureia/administração & dosagem , Ureia/farmacocinética , 11-beta-Hidroxiesteroide Desidrogenase Tipo 1/metabolismo , Administração Oral , Animais , Sítios de Ligação/fisiologia , Disponibilidade Biológica , Células CHO , Cricetinae , Cricetulus , Humanos , Macaca fascicularis , Camundongos , Ratos , Relação Estrutura-Atividade , Ureia/análogos & derivadosRESUMO
A novel class of CGRP receptor antagonists was rationally designed by modifying a highly potent, but structurally complex, CGRP receptor antagonist. Initial modifications focused on simplified structures, with increased flexibility. Subsequent to the preparation of a less-potent but more flexible lead, classic medicinal chemistry methods were applied to restore high affinity (compound 22, CGRP Ki=0.035 nM) while maintaining structural diversity relative to the lead. Good selectivity against the closely related adrenomedullin-2 receptor was also achieved.
Assuntos
Acetamidas/química , Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Compostos de Espiro/química , Acetamidas/síntese química , Acetamidas/farmacologia , Animais , Linhagem Celular , Desenho de Fármacos , Humanos , Ratos , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/metabolismo , Compostos de Espiro/síntese química , Compostos de Espiro/farmacologia , Relação Estrutura-AtividadeRESUMO
Rational modification of a previously identified spirohydantoin lead structure has identified a series of potent spiroazaoxindole CGRP receptor antagonists. The azaoxindole was found to be a general replacement for the hydantoin that consistently improved in vitro potency. The combination of the indanylspiroazaoxindole and optimized benzimidazolinones led to highly potent antagonists (e.g., 25, CGRP K(i)=40pM). The closely related compound 27 demonstrated good oral bioavailability in dog and rhesus.
Assuntos
Antagonistas do Receptor do Peptídeo Relacionado ao Gene de Calcitonina , Indóis/síntese química , Compostos de Espiro/síntese química , Administração Oral , Animais , Disponibilidade Biológica , Cães , Descoberta de Drogas , Humanos , Indóis/farmacologia , Macaca mulatta , Oxindóis , Compostos de Espiro/farmacologia , Relação Estrutura-AtividadeRESUMO
Inhibition of renin has been shown to be successful in managing hypertension and maintaining cardiac health. Canine models have played a key role in preclinical assessment of renin inhibitors. Here we report the cloning of canine prorenin gene. The amino acid sequence of mature canine renin was approximately 70% identical to that of human renin. The full-length prorenin was expressed in HEK 293 cells, purified and converted to its active form by trypsin-mediated cleavage of the 43 residue propeptide. The mature enzyme was characterized by steady-state kinetics using a peptide corresponding to the canine angiotensinogen sequence, Ac-Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu-Leu-Val-Tyr-Ser-OH (cleavage between Leu(10)-Leu(11)). The reaction followed Michaelis-Menten kinetics with a K(M) of 120 microM and a second-order rate constant (k(cat)/K(M)) of 1.7 x 10(5) M(-)(1)s(-)(1). The enzyme was inhibited by various human renin inhibitors, but at reduced potency compared to the human renin. The basis of the species specificity was investigated by mutagenesis. Based on primary sequence and structural alignments, three mutants were prepared (G149S-S150T, V286L, G149S-S150T-V286L). Each mutant yielded catalytically active enzymes with lower specific activities than native canine renin. V286L had the greatest effect on substrate specificity, while G149S, S150T mutations produced enzymes with inhibitor profiles similar to human renin.
Assuntos
Renina/genética , Renina/metabolismo , Sequência de Aminoácidos , Animais , Linhagem Celular , Clonagem Molecular , Cães , Inibidores Enzimáticos/farmacologia , Precursores Enzimáticos/isolamento & purificação , Precursores Enzimáticos/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Cinética , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Renina/química , Homologia de Sequência de AminoácidosRESUMO
The risks of performing endoscopy become more complex when the patient is pregnant. The endoscopist has to consider all the factors that affect the health of both the patient and the fetus. Although pregnant patients are generally healthy, they may have changes in blood pressure and volume status as well as alterations in tolerance of anesthesia and luminal distention. Maternal complications will impact the health of the fetus. In addition, the fetus can be directly affected by procedural medications, mechanical factors, and therapeutic interventions. The endoscopist must be able to minimize the risks to the fetus and provide the pregnant patient with a safe and comfortable procedure. This review focuses on the risks of upper endoscopy as they relate to the health of a pregnant woman and the fetus.
Assuntos
Endoscopia Gastrointestinal , Complicações na Gravidez/terapia , Eletrocoagulação , Endoscopia do Sistema Digestório , Feminino , Gastrostomia , Humanos , Hiperêmese Gravídica/terapia , Pseudocisto Pancreático/terapia , Gravidez , Segurança , EscleroterapiaRESUMO
The field of small-molecule orexin antagonist research has evolved rapidly in the last 15 years from the discovery of the orexin peptides to clinical proof-of-concept for the treatment of insomnia. Clinical programs have focused on the development of antagonists that reversibly block the action of endogenous peptides at both the orexin 1 and orexin 2 receptors (OX1 R and OX2 R), termed dual orexin receptor antagonists (DORAs), affording late-stage development candidates including Merck's suvorexant (new drug application filed 2012). Full characterization of the pharmacology associated with antagonism of either OX1 R or OX2 R alone has been hampered by the dearth of suitable subtype-selective, orally bioavailable ligands. Herein, we report the development of a selective orexin 2 antagonist (2-SORA) series to afford a potent, orally bioavailable 2-SORA ligand. Several challenging medicinal chemistry issues were identified and overcome during the development of these 2,5-disubstituted nicotinamides, including reversible CYP inhibition, physiochemical properties, P-glycoprotein efflux and bioactivation. This article highlights structural modifications the team utilized to drive compound design, as well as in vivo characterization of our 2-SORA clinical candidate, 5''-chloro-N-[(5,6-dimethoxypyridin-2-yl)methyl]-2,2':5',3''-terpyridine-3'-carboxamide (MK-1064), in mouse, rat, dog, and rhesus sleep models.