RESUMO
The angiotensin II receptors AT1R and AT2R serve as key components of the renin-angiotensin-aldosterone system. AT1R has a central role in the regulation of blood pressure, but the function of AT2R is unclear and it has a variety of reported effects. To identify the mechanisms that underlie the differences in function and ligand selectivity between these receptors, here we report crystal structures of human AT2R bound to an AT2R-selective ligand and to an AT1R/AT2R dual ligand, capturing the receptor in an active-like conformation. Unexpectedly, helix VIII was found in a non-canonical position, stabilizing the active-like state, but at the same time preventing the recruitment of G proteins or ß-arrestins, in agreement with the lack of signalling responses in standard cellular assays. Structure-activity relationship, docking and mutagenesis studies revealed the crucial interactions for ligand binding and selectivity. Our results thus provide insights into the structural basis of the distinct functions of the angiotensin receptors, and may guide the design of new selective ligands.
Assuntos
Modelos Moleculares , Receptor Tipo 2 de Angiotensina/química , Receptor Tipo 2 de Angiotensina/metabolismo , Bloqueadores do Receptor Tipo 2 de Angiotensina II/química , Bloqueadores do Receptor Tipo 2 de Angiotensina II/metabolismo , Sítios de Ligação/genética , Cristalografia por Raios X , Desenho de Fármacos , Proteínas Heterotriméricas de Ligação ao GTP/química , Proteínas Heterotriméricas de Ligação ao GTP/metabolismo , Humanos , Ligantes , Simulação de Acoplamento Molecular , Mutação , Ligação Proteica , Conformação Proteica , Receptor Tipo 1 de Angiotensina/química , Receptor Tipo 1 de Angiotensina/metabolismo , Receptor Tipo 2 de Angiotensina/agonistas , Receptor Tipo 2 de Angiotensina/genética , Transdução de Sinais , Relação Estrutura-Atividade , Especificidade por Substrato/genética , beta-Arrestinas/metabolismoRESUMO
Glutamate plays a key role in cognition and mood, and it has been shown that inhibiting ionotropic glutamate receptors disrupts cognition, while enhancing ionotropic receptor activity is pro-cognitive. One approach to elevating glutamatergic tone has been to antagonize presynaptic metabotropic glutamate receptor 2 (mGluR2). A desire for selectivity over the largely homologous mGluR3 motivated a strategy to achieve selectivity through the identification of mGluR2 negative allosteric modulators (NAMs). Extensive screening and optimization efforts led to the identification of a novel series of 4-arylquinoline-2-carboxamides. This series was optimized for mGluR2 NAM potency, clean off-target activity, and desirable physical properties, which resulted in the identification of improved C4 and C7 substituents. The initial lead compound from this series was Ames-positive in a single strain with metabolic activation, indicating that a reactive metabolite was likely responsible for the genetic toxicity. Metabolic profiling and Ames assessment across multiple analogs identified key structure-activity relationships associated with Ames positivity. Further optimization led to the Ames-negative mGluR2 negative allosteric modulator MK-8768.
RESUMO
HCV NS3/4a protease inhibitors are proven therapeutic agents against chronic hepatitis C virus infection, with boceprevir and telaprevir having recently received regulatory approval as add-on therapy to pegylated interferon/ribavirin for patients harboring genotype 1 infections. Overcoming antiviral resistance, broad genotype coverage, and a convenient dosing regimen are important attributes for future agents to be used in combinations without interferon. In this communication, we report the preclinical profile of MK-5172, a novel P2-P4 quinoxaline macrocyclic NS3/4a protease inhibitor currently in clinical development. The compound demonstrates subnanomolar activity against a broad enzyme panel encompassing major hepatitis C virus (HCV) genotypes as well as variants resistant to earlier protease inhibitors. In replicon selections, MK-5172 exerted high selective pressure, which yielded few resistant colonies. In both rat and dog, MK-5172 demonstrates good plasma and liver exposures, with 24-h liver levels suggestive of once-daily dosing. When administered to HCV-infected chimpanzees harboring chronic gt1a or gt1b infections, MK-5172 suppressed viral load between 4 to 5 logs at a dose of 1 mg/kg of body weight twice daily (b.i.d.) for 7 days. Based on its preclinical profile, MK-5172 is anticipated to be broadly active against multiple HCV genotypes and clinically important resistance variants and highly suited for incorporation into newer all-oral regimens.
Assuntos
Hepacivirus/efeitos dos fármacos , Inibidores de Proteases/farmacologia , Quinoxalinas/farmacologia , Quinoxalinas/farmacocinética , Proteínas não Estruturais Virais/antagonistas & inibidores , Amidas , Animais , Antivirais/farmacologia , Carbamatos , Ciclopropanos , Cães , Farmacorresistência Viral , Genótipo , Hepacivirus/enzimologia , Hepacivirus/genética , Hepatite C Crônica/tratamento farmacológico , Hepatite C Crônica/virologia , Fígado/efeitos dos fármacos , Pan troglodytes , Quinoxalinas/metabolismo , Ratos , Sulfonamidas , Carga Viral/efeitos dos fármacosRESUMO
A series of macrocyclic compounds containing a cyclic constraint in the P2-P4 linker region have been discovered and shown to exhibit excellent HCV NS3/4a genotype 3a and genotype 1b R155K, A156T, A156V, and D168V mutant activity while maintaining high rat liver exposure. The effect of the constraint is most dramatic against gt 1b A156 mutants where ~20-fold improvements in potency are achieved by introduction of a variety of ring systems into the P2-P4 linker.
Assuntos
Proteínas de Transporte/antagonistas & inibidores , Hepacivirus/enzimologia , Compostos Macrocíclicos/química , Inibidores de Proteases/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Sítios de Ligação , Proteínas de Transporte/metabolismo , Domínio Catalítico , Ciclização , Genótipo , Meia-Vida , Hepacivirus/genética , Peptídeos e Proteínas de Sinalização Intracelular , Cinética , Fígado/metabolismo , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/farmacocinética , Simulação de Acoplamento Molecular , Mutação , Inibidores de Proteases/síntese química , Inibidores de Proteases/farmacocinética , Ratos , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/metabolismoRESUMO
A series of macrocyclic compounds containing 2-substituted-quinoline moieties have been discovered and shown to exhibit excellent HCV NS3/4a genotype 3a and genotype 1b R155K mutant activity while maintaining the high rat liver exposure. Cyclization of the 2-substituted quinoline substituent led to a series of tricyclic P2 compounds which also display superb gt3a potency.
Assuntos
Proteínas de Transporte/antagonistas & inibidores , Hepacivirus/enzimologia , Compostos Macrocíclicos/química , Inibidores de Proteases/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Proteínas de Transporte/metabolismo , Ciclização , Genótipo , Meia-Vida , Hepacivirus/genética , Peptídeos e Proteínas de Sinalização Intracelular , Cinética , Fígado/metabolismo , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/farmacocinética , Inibidores de Proteases/síntese química , Inibidores de Proteases/farmacocinética , Quinolinas/química , Ratos , Relação Estrutura-Atividade , Proteínas não Estruturais Virais/metabolismoRESUMO
Positron emission tomography (PET) ligands play an important role in the development of therapeutics by serving as target engagement or pharmacodynamic biomarkers. Here, we describe the discovery and translation of the PET tracer [11C]MK-6884 from rhesus monkeys to patients with Alzheimer's disease (AD). [3H]MK-6884/[11C]MK-6884 binds with high binding affinity and good selectivity to an allosteric site on M4 muscarinic cholinergic receptors (M4Rs) in vitro and shows a regional distribution in the brain consistent with M4R localization in vivo. The tracer demonstrates target engagement of positive allosteric modulators of the M4R (M4 PAMs) through competitive binding interactions. [11C]MK-6884 binding is enhanced in vitro by the orthosteric M4R agonist carbachol and indirectly in vivo by the acetylcholinesterase inhibitor donepezil in rhesus monkeys and healthy volunteers, consistent with its pharmacology as a highly cooperative M4 PAM. PET imaging of [11C]MK-6884 in patients with AD identified substantial regional differences quantified as nondisplaceable binding potential (BPND) of [11C]MK-6884. These results suggest that [11C]MK-6884 is a useful target engagement biomarker for M4 PAMs but may also act as a sensitive probe of neuropathological changes in the brains of patients with AD.
Assuntos
Doença de Alzheimer , Acetilcolinesterase , Doença de Alzheimer/diagnóstico por imagem , Animais , Humanos , Macaca mulatta , Tomografia por Emissão de Pósitrons/métodos , Receptores MuscarínicosRESUMO
Narcolepsy type 1 (NT1) is a chronic neurological disorder that impairs the brain's ability to control sleep-wake cycles. Current therapies are limited to the management of symptoms with modest effectiveness and substantial adverse effects. Agonists of the orexin receptor 2 (OX2R) have shown promise as novel therapeutics that directly target the pathophysiology of the disease. However, identification of drug-like OX2R agonists has proven difficult. Here we report cryo-electron microscopy structures of active-state OX2R bound to an endogenous peptide agonist and a small-molecule agonist. The extended carboxy-terminal segment of the peptide reaches into the core of OX2R to stabilize an active conformation, while the small-molecule agonist binds deep inside the orthosteric pocket, making similar key interactions. Comparison with antagonist-bound OX2R suggests a molecular mechanism that rationalizes both receptor activation and inhibition. Our results enable structure-based discovery of therapeutic orexin agonists for the treatment of NT1 and other hypersomnia disorders.
Assuntos
Aminopiridinas/química , Azepinas/química , Antagonistas dos Receptores de Orexina/química , Receptores de Orexina/química , Peptídeos/química , Medicamentos Indutores do Sono/química , Sulfonamidas/química , Triazóis/química , Aminopiridinas/metabolismo , Azepinas/metabolismo , Sítios de Ligação , Clonagem Molecular , Microscopia Crioeletrônica , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Células HEK293 , Humanos , Simulação de Dinâmica Molecular , Antagonistas dos Receptores de Orexina/metabolismo , Receptores de Orexina/agonistas , Receptores de Orexina/metabolismo , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Domínios e Motivos de Interação entre Proteínas , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Medicamentos Indutores do Sono/metabolismo , Sulfonamidas/metabolismo , Triazóis/metabolismoRESUMO
The administration of hepatitis C virus (HCV) NS3/4A protease inhibitors to patients with chronic HCV infections has demonstrated that they have dramatic antiviral effects and that compounds acting via this mechanism are likely to form a key component of future anti-HCV therapy. We report here on the preclinical profile of MK-7009, an inhibitor of genotype 1a and 1b proteases at subnanomolar concentrations with modestly shifted potency against genotype 2a and 2b proteases at low nanomolar concentrations. Potent activity was also observed in a cell-based HCV replicon assay in the presence of added human serum (50%). In multiple species evaluated in preclinical studies, the MK-7009 concentrations in the liver were maintained at a significant multiple of the cell-based replicon 50% effective concentration over 12 to 24 h following the administration of moderate oral doses (5 to 10 mg per kg of body weight). MK-7009 also had excellent selectivity against both a range of human proteases and a broad panel of pharmacologically relevant ion channels, receptors, and enzymes. On the basis of this favorable profile, MK-7009 was selected for clinical development and is currently being evaluated in controlled clinical trials with both healthy volunteers and HCV-infected patients.
Assuntos
Antivirais/farmacologia , Hepacivirus/efeitos dos fármacos , Indóis/farmacologia , Inibidores de Proteases/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/farmacocinética , Área Sob a Curva , Linhagem Celular , Ciclopropanos , Cães , Genótipo , Meia-Vida , Hepacivirus/enzimologia , Hepacivirus/genética , Humanos , Indóis/farmacocinética , Interferon alfa-2 , Interferon-alfa/farmacologia , Isoindóis , Lactamas Macrocíclicas , Leucina/análogos & derivados , Macaca mulatta , Pan troglodytes , Prolina/análogos & derivados , Inibidores de Proteases/farmacocinética , Ratos , Proteínas Recombinantes , Replicon , Especificidade por Substrato , Sulfonamidas , Proteínas não Estruturais Virais/genéticaRESUMO
A novel catalytic alkyne cross-coupling reaction is reported which connects tertiary propargyl alcohols with omega-alkynylnitriles with perfect atom economy. This remarkable process generates highly functionalized, stereodefined dienones that are formal aldol products in a single step. Moreover, the specificity of the cyano substituent for this reaction demonstrates the unique and somewhat underappreciated properties of that functional group.
RESUMO
Molecular modeling of inhibitor bound full length HCV NS3/4A protease structures proved to be a valuable tool in the design of a new series of potent NS3 protease inhibitors. Optimization of initial compounds provided 25a. The in vitro activity and selectivity as well as the rat pharmacokinetic profile of 25a compare favorably with the data for other NS3/4A protease inhibitors currently in clinical development for the treatment of HCV.
Assuntos
Hepacivirus/enzimologia , Compostos Macrocíclicos/química , Inibidores de Serina Proteinase/química , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Compostos Macrocíclicos/síntese química , Compostos Macrocíclicos/farmacocinética , Compostos Macrocíclicos/farmacologia , Modelos Moleculares , Ratos , Inibidores de Serina Proteinase/síntese química , Inibidores de Serina Proteinase/farmacocinética , Inibidores de Serina Proteinase/farmacologia , Proteínas não Estruturais Virais/químicaRESUMO
Hepatitis C virus (HCV) infection is a major health issue around the world and HCV NS3/4a protease inhibitors have been the focus of intensive research for the past 20 years. From the first identification of substrate-derived peptide inhibitors to the complex, macrocyclic compounds, including paritaprevir and grazoprevir, that are currently available, the field has used structure-based design to confront the issues of potency, resistance and pharmacokinetics. Numerous breakthrough structures from a multitude of companies have led to compounds that are now key components of combination therapies with cure rates of >90%. Herein, we detail the compounds that have advanced to clinical trials including their design and their impact on the NS3/4a protease field.
Assuntos
Antivirais/farmacologia , Hepatite C/tratamento farmacológico , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Desenho de Fármacos , Hepacivirus/efeitos dos fármacos , Hepacivirus/enzimologia , Hepatite C/virologia , Humanos , Inibidores de Proteases/farmacologia , Relação Estrutura-AtividadeRESUMO
Herein, we describe the development of a functionally selective liver X receptor ß (LXRß) agonist series optimized for Emax selectivity, solubility, and physical properties to allow efficacy and safety studies in vivo. Compound 9 showed central pharmacodynamic effects in rodent models, evidenced by statistically significant increases in apolipoprotein E (apoE) and ATP-binding cassette transporter levels in the brain, along with a greatly improved peripheral lipid safety profile when compared to those of full dual agonists. These findings were replicated by subchronic dosing studies in non-human primates, where cerebrospinal fluid levels of apoE and amyloid-ß peptides were increased concomitantly with an improved peripheral lipid profile relative to that of nonselective compounds. These results suggest that optimization of LXR agonists for Emax selectivity may have the potential to circumvent the adverse lipid-related effects of hepatic LXR activity.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Apolipoproteínas E/líquido cefalorraquidiano , Benzamidas/química , Benzamidas/farmacologia , Receptores Nucleares Órfãos/agonistas , Piperidinas/química , Piperidinas/farmacologia , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cães , Células Hep G2 , Humanos , Lipídeos/análise , Fígado/efeitos dos fármacos , Fígado/metabolismo , Receptores X do Fígado , Locomoção/efeitos dos fármacos , Macaca mulatta , Células Madin Darby de Rim Canino , Camundongos , Camundongos TransgênicosRESUMO
The demand for new chemicals spanning the fields of health care to materials science combined with the pressure to produce these substances in an environmentally benign fashion pose great challenges to the synthetic chemical community. The maximization of synthetic efficiency by the conversion of simple building blocks into complex targets remains a fundamental goal. In this context, ruthenium complexes catalyze a number of non-metathesis conversions and allow the rapid assembly of complex molecules with high selectivity and atom economy. These complexes often exhibit unusual reactivity. Careful consideration of the mechanistic underpinnings of the transformations can lead to the design of new reactions and the discovery of new reactivity.
Assuntos
Compostos Organometálicos/química , Rutênio/química , Alcenos/química , Alcinos/química , Catálise , Ciclização , Ésteres/síntese química , Ésteres/química , Cetonas/síntese química , Cetonas/química , Estrutura Molecular , Oxirredução , EstereoisomerismoRESUMO
This article describes recent medicinal chemistry progress toward selective potentiators of the metabotropic glutamate receptor 2 (mGluR2). Groups at Lilly and Merck have identified new classes of potentiators that exhibit selectivity for mGluR2 over the seven other subtypes of mGluRs. Structure-activity relationships as well as pharmacokinetic properties and in vivo activity are reviewed.
Assuntos
Agonistas de Aminoácidos Excitatórios/farmacologia , Agonistas de Aminoácidos Excitatórios/farmacocinética , Receptores de Glutamato Metabotrópico/agonistas , Regulação Alostérica , Animais , Desenho de Fármacos , Humanos , Receptores de Glutamato Metabotrópico/metabolismo , Relação Estrutura-AtividadeRESUMO
With the goal of identifying inhibitors of hepatitis C virus (HCV) NS3/4a protease that are potent against a wide range of genotypes and clinically relevant mutant viruses, several subseries of macrocycles were investigated based on observations made during the discovery of MK-5172. Quinazolinone-containing macrocycles were identified as promising leads, and optimization for superior cross-genotype and mutant enzyme potency as well as rat liver and plasma concentrations following oral dosing, led to the development of MK-2748. Additional investigation of a series of bis-macrocycles containing a fused 18- and 15-membered ring system were also optimized for the same properties, leading to the discovery of MK-6325. Both compounds display the broad genotype and mutant potency necessary for clinical development as next-generation HCV NS3/4a protease inhibitors.
Assuntos
Antivirais/farmacologia , Hepacivirus/enzimologia , Compostos Macrocíclicos/farmacologia , Quinazolinonas/farmacologia , Sulfonas/farmacologia , Proteínas não Estruturais Virais/antagonistas & inibidores , Animais , Antivirais/química , Antivirais/farmacocinética , Cristalografia por Raios X , Descoberta de Drogas , Hepacivirus/efeitos dos fármacos , Hepacivirus/genética , Hepatite C/tratamento farmacológico , Hepatite C/virologia , Humanos , Compostos Macrocíclicos/química , Compostos Macrocíclicos/farmacocinética , Modelos Moleculares , Mutação , Quinazolinonas/química , Quinazolinonas/farmacocinética , Ratos , Sulfonas/farmacocinética , Proteínas não Estruturais Virais/genéticaRESUMO
[reaction: see text] The chemoselectivity of the ruthenium-catalyzed hydrative diyne cylization is explored in an expeditious synthesis of the tricyclic alkaloids cylindricine C, D, and E.
Assuntos
Alcaloides/química , Alcaloides/síntese química , Compostos Heterocíclicos com 3 Anéis/química , Compostos Heterocíclicos com 3 Anéis/síntese química , Quinolonas/química , Quinolonas/síntese química , Rutênio/química , Ciclização , Isomerismo , Estrutura MolecularRESUMO
A novel route to the neuroexcitatory amino acid, kainic acid, is developed. The key concept derives from a ruthenium-catalyzed cycloisomerization of a tethered alkyne-propargyl alcohol to form a cyclic 2-vinyl-1-acyl compound. A single stereocenter introduced by an asymmetric reduction of a ketone sets the stage for all the other stereocenters. A novel 1,6-addition of silyl cuprate serves to install a hydroxyl group at the diene termines. [reaction: see text]
Assuntos
Alcinos/química , Ácido Caínico/síntese química , Propanóis/química , Rutênio/química , Catálise , Agonistas de Aminoácidos Excitatórios/síntese química , Cetonas/química , Compostos Organometálicos/química , Oxirredução , EstereoisomerismoRESUMO
The ruthenium-catalyzed cycloisomerization of diynes containing one silyl alkyne and one propargyl alcohol yields 2-silyl-[6H]-pyrans instead of the expected unsaturated acylsilanes except when additional conjugation of a aromatic ring is present at the delta-position. Under certain conditions, a facile ruthenium-catalyzed isomerization of the product takes place as well. This regioselectivity of the cyclization can be controlled by the choice of solvent system. DFT calculations confirm the expected greater stability of the silyl-pyrans relative to the acylsilanes.
Assuntos
Alcinos/química , Propanóis/química , Rutênio/química , Catálise , Ciclização , IsomerismoRESUMO
We have previously reported the discovery of our P2-P4 macrocyclic HCV NS3/4a protease inhibitor MK-5172, which in combination with the NS5a inhibitor MK-8742 recently received a breakthrough therapy designation from the US FDA for treatment of chronic HCV infection. Our goal for the next generation NS3/4a inhibitor was to achieve pan-genotypic activity while retaining the pharmacokinetic profile of MK-5172. One of the areas for follow-up investigation involved replacement of the quinoxaline moiety in MK-5172 with a quinoline and studying the effect of substitution at 4-position of the quinoline. The rationale for this effort was based on molecular modeling, which indicated that such modifications would improve interactions with the S2 subsite, in particular with D79. We wish to report herein the discovery of highly potent inhibitors with pan-genotypic activity and an improved profile over MK-5172, especially against gt-3a and A156 mutants.