RESUMEN
An internal HTS effort identified a novel PDE2 inhibitor series that was subsequently optimized for improved PDE2 activity and off-target selectivity. The optimized lead, compound 4, improved cognitive performance in a rodent novel object recognition task as well as a non-human primate object retrieval task. In addition, co-crystallization studies of close analog of 4 in the PDE2 active site revealed unique binding interactions influencing the high PDE isoform selectivity.
Asunto(s)
Ácido Acético/farmacología , Disfunción Cognitiva/tratamiento farmacológico , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/antagonistas & inhibidores , Indoles/farmacología , Inhibidores de Fosfodiesterasa/farmacología , Ácido Acético/síntesis química , Ácido Acético/química , Animales , Dominio Catalítico/efectos de los fármacos , Disfunción Cognitiva/metabolismo , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/metabolismo , Relación Dosis-Respuesta a Droga , Indoles/síntesis química , Indoles/química , Estructura Molecular , Inhibidores de Fosfodiesterasa/síntesis química , Inhibidores de Fosfodiesterasa/química , Ratas , Relación Estructura-ActividadRESUMEN
We have identified a novel PDE2 inhibitor series using fragment-based screening. Pyrazolopyrimidine fragment 1, while possessing weak potency (Kiâ¯=â¯22.4⯵M), exhibited good binding efficiencies (LBEâ¯=â¯0.49, LLEâ¯=â¯4.48) to serve as a start for structure-based drug design. With the assistance of molecular modeling and X-ray crystallography, this fragment was developed into a series of potent PDE2 inhibitors with good physicochemical properties. Compound 16, a PDE2 selective inhibitor, was identified that exhibited favorable rat pharmacokinetic properties.
Asunto(s)
Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/antagonistas & inhibidores , Diseño de Fármacos , Inhibidores de Fosfodiesterasa/química , Animales , Sitios de Unión , Dominio Catalítico , Cristalografía por Rayos X , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/metabolismo , Semivida , Humanos , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , Conformación Molecular , Simulación de Dinámica Molecular , Inhibidores de Fosfodiesterasa/metabolismo , Inhibidores de Fosfodiesterasa/farmacocinética , Pirazoles/química , Pirazoles/metabolismo , Pirazoles/farmacocinética , Pirimidinas/química , Pirimidinas/metabolismo , Pirimidinas/farmacocinética , Ratas , Relación Estructura-ActividadRESUMEN
The voltage-gated sodium channel Nav1.7 is a genetically validated target for the treatment of pain with gain-of-function mutations in man eliciting a variety of painful disorders and loss-of-function mutations affording insensitivity to pain. Unfortunately, drugs thought to garner efficacy via Nav1 inhibition have undesirable side effect profiles due to their lack of selectivity over channel isoforms. Herein we report the discovery of a novel series of orally bioavailable arylsulfonamide Nav1.7 inhibitors with high levels of selectivity over Nav1.5, the Nav isoform responsible for cardiovascular side effects, through judicious use of parallel medicinal chemistry and physicochemical property optimization. This effort produced inhibitors such as compound 5 with excellent potency, selectivity, behavioral efficacy in a rodent pain model, and efficacy in a mouse itch model suggestive of target modulation.
Asunto(s)
Sulfonamidas/química , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Administración Oral , Animales , Modelos Animales de Enfermedad , Evaluación Preclínica de Medicamentos , Semivida , Concentración 50 Inhibidora , Ratones , Canal de Sodio Activado por Voltaje NAV1.7/química , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Nitrógeno/química , Dolor/tratamiento farmacológico , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Ratas , Relación Estructura-Actividad , Sulfonamidas/farmacocinética , Sulfonamidas/uso terapéutico , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacocinética , Bloqueadores del Canal de Sodio Activado por Voltaje/uso terapéuticoRESUMEN
The IC50 of a beta-secretase (BACE-1) lead compound was improved â¼200-fold from 11 µM to 55 nM through the addition of a single methyl group. Computational chemistry, small molecule NMR, and protein crystallography capabilities were used to compare the solution conformation of the ligand under varying pH conditions to its conformation when bound in the active site. Chemical modification then explored available binding pockets adjacent to the ligand. A strategically placed methyl group not only maintained the required pKa of the piperidine nitrogen and filled a small hydrophobic pocket, but more importantly, stabilized the conformation best suited for optimized binding to the receptor.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Hidantoínas/química , Hidantoínas/farmacología , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Ácido Aspártico Endopeptidasas/metabolismo , Cristalografía por Rayos X , Relación Dosis-Respuesta a Droga , Humanos , Hidantoínas/síntesis química , Metilación , Modelos Moleculares , Estructura Molecular , Relación Estructura-ActividadRESUMEN
The measurement of receptor occupancy (RO) using positron emission tomography (PET) has been instrumental in guiding discovery and development of CNS directed therapeutics. We and others have investigated muscarinic acetylcholine receptor 4 (M4) positive allosteric modulators (PAMs) for the treatment of symptoms associated with neuropsychiatric disorders. In this article, we describe the synthesis, in vitro, and in vivo characterization of a series of central pyridine-related M4 PAMs that can be conveniently radiolabeled with carbon-11 as PET tracers for the in vivo imaging of an allosteric binding site of the M4 receptor. We first demonstrated its feasibility by mapping the receptor distribution in mouse brain and confirming that a lead molecule 1 binds selectively to the receptor only in the presence of the orthosteric agonist carbachol. Through a competitive binding affinity assay and a number of physiochemical properties filters, several related compounds were identified as candidates for in vivo evaluation. These candidates were then radiolabeled with 11C and studied in vivo in rhesus monkeys. This research eventually led to the discovery of the clinical radiotracer candidate [11C]MK-6884.
Asunto(s)
Regulación Alostérica/efectos de los fármacos , Agonistas Muscarínicos/farmacología , Piridinas/farmacología , Receptor Muscarínico M4/agonistas , Animales , Células CHO , Radioisótopos de Carbono/química , Radioisótopos de Carbono/farmacología , Cricetulus , Humanos , Macaca mulatta , Agonistas Muscarínicos/química , Enfermedades Neurodegenerativas/diagnóstico por imagen , Enfermedades Neurodegenerativas/tratamiento farmacológico , Enfermedades Neurodegenerativas/metabolismo , Tomografía de Emisión de Positrones , Piridinas/química , Receptor Muscarínico M4/metabolismoRESUMEN
Herein we describe the discovery and optimization of a new series of 2,3-disubstituted and 2,3,6-trisubstituted muscarinic acetylcholine receptorâ 4 (M4 ) positive allosteric modulators (PAMs). Iterative libraries enabled rapid exploration of one-dimensional structure-activity relationships (SAR) and identification of potency-enhancing heterocycle and N-alkyl pyrazole substituents. Further optimization led to identification of the potent, receptor-subtype-selective, brain-penetrant tool compound 24 (7-[3-[1-[(1-fluorocyclopentyl)methyl]pyrazol-4-yl]-6-methyl-2-pyridyl]-3-methoxycinnoline). It is efficacious in preclinical assays that are predictive of antipsychotic effects, producing dose-dependent reversal of amphetamine-induced hyperlocomotion in rats and mice, but not in M4 knockout mice. Cholinergic-related adverse effects observed in rats treated with 24 at unbound plasma concentrations more than 3-fold higher than an efficacious dose in the hyperlocomotion assay were fewer and less severe than those observed in rats treated with the nonselective M4 agonist xanomeline, suggesting a receptor-subtype-selective PAM has the potential for an improved safety profile.
Asunto(s)
Descubrimiento de Drogas , Piridinas/química , Piridinas/farmacología , Receptor Muscarínico M4/efectos de los fármacos , Regulación Alostérica , Animales , Humanos , Ratas , Receptor Muscarínico M4/metabolismo , Relación Estructura-ActividadRESUMEN
HIV-1 integrase catalyzes the insertion of viral DNA into the genome of the host cell. Integrase inhibitor N-(4-fluorobenzyl)-8-hydroxy-1,6-naphthyridine-7-carboxamide selectively inhibits the strand transfer process of integration. 4-Substituted pyrrolidinones possessing various groups on the pyrrolidinone nitrogen were introduced at the 5-position of the naphthyridine scaffold. These analogs exhibit excellent activity against viral replication in a cell-based assay. The preparation of these compounds was enabled by a three-step, two-pot reaction sequence from a common butenolide intermediate.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Fármacos Anti-VIH/farmacología , Inhibidores de Integrasa VIH/síntesis química , Inhibidores de Integrasa VIH/farmacología , Integrasa de VIH/metabolismo , VIH-1/efectos de los fármacos , Naftiridinas/síntesis química , Naftiridinas/farmacología , Administración Oral , Animales , Fármacos Anti-VIH/química , Inhibidores de Integrasa VIH/química , Estructura Molecular , Naftiridinas/química , Ratas , Relación Estructura-ActividadRESUMEN
Owing to slow rotation of a sterically constrained dimethylamide substituent, two slowly interconverting enantiomers of a preclinical candidate for pharmaceutical development, 1, (6-(3-Chloro-4-fluoro-benzyl)-4-hydroxy-2-methyl-3,5-dioxo-2,3,5,6,7,8-hexahydro-[2,6]naphthyridine-1-carboxylic acid dimethylamide) are observed by chiral chromatography. Isolation of pure enantiomer by preparative chiral chromatography followed by enantiopurity analysis over time allowed for a study of the kinetics of enantiomer interconversion under a variety of conditions. Relatively slow racemization was observed in alcohol solvents, with a half life on the order of 5-10 h. A dramatic influence of aqueous buffer pH on racemization was noted, with higher pH leading to rapid racemization within a few minutes, and lower pH leading to essentially no racemization for periods up to a week. A hypothesis explaining this unusual effect of pH on carboxamide bond rotation is offered, and some suggestions for potential utility of such a system are considered.
Asunto(s)
Amidas/química , Cromatografía Líquida de Alta Presión/métodos , Dimetilaminas/química , Naftiridinas/química , Rotación Óptica , Dicroismo Circular , Concentración de Iones de Hidrógeno , Espectrofotometría UltravioletaRESUMEN
Naphthyridine 7 inhibits the strand transfer of the integration process catalyzed by integrase with an IC50 of 10 nM and inhibits 95% of the spread of HIV-1 infection in cell culture at 0.39 microM. It does not exhibit cytotoxicity in cell culture at < or =12.5 microM and shows a good pharmacokinetic profile when dosed orally to rats. The antiviral activity of 7 and its effect on integration were confirmed using viruses with specific integrase mutations.
Asunto(s)
Fármacos Anti-VIH/síntesis química , Inhibidores de Integrasa VIH/síntesis química , VIH-1/efectos de los fármacos , Naftiridinas/síntesis química , Administración Oral , Animales , Fármacos Anti-VIH/química , Fármacos Anti-VIH/farmacología , Línea Celular , Inhibidores de Integrasa VIH/química , Inhibidores de Integrasa VIH/farmacología , Humanos , Inyecciones Intravenosas , Naftiridinas/química , Naftiridinas/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
We have identified several series of small molecule inhibitors of TrkA with unique binding modes. The starting leads were chosen to maximize the structural and binding mode diversity derived from a high throughput screen of our internal compound collection. These leads were optimized for potency and selectivity employing a structure based drug design approach adhering to the principles of ligand efficiency to maximize binding affinity without overly relying on lipophilic interactions. This endeavor resulted in the identification of several small molecule pan-Trk inhibitor series that exhibit high selectivity for TrkA/B/C versus a diverse panel of kinases. We have also demonstrated efficacy in both inflammatory and neuropathic pain models upon oral dosing. Herein we describe the identification process, hit-to-lead progression, and binding profiles of these selective pan-Trk kinase inhibitors.
Asunto(s)
Dolor Crónico/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/química , Receptor trkA/antagonistas & inhibidores , Animales , Evaluación Preclínica de Medicamentos , Humanos , Indoles/química , Indoles/farmacocinética , Ligandos , Modelos Moleculares , Inhibidores de Proteínas Quinasas/farmacocinética , Pirimidinas/química , Pirimidinas/farmacocinética , Ratas , Bibliotecas de Moléculas Pequeñas/uso terapéutico , Relación Estructura-Actividad , Triazoles/química , Triazoles/farmacocinética , Urea/análogos & derivados , Urea/química , Urea/farmacocinéticaRESUMEN
The cognitive deficits associated with schizophrenia are recognized as a core component of the disorder, yet there remain no available therapeutics to treat these symptoms of the disease. As a result, there is a need for establishing predictive preclinical models to identify the therapeutic potential of novel compounds. In the present study, rhesus monkeys were trained in the object retrieval-detour task, which is dependent on the prefrontal cortex, a brain region implicated in the cognitive deficits associated with schizophrenia. The NMDA receptor antagonist ketamine significantly impaired performance without affecting measures of motor or visuospatial abilities. Pre-treatment with the nicotinic α7 agonist GTS-21 (0.03 mg/kg) significantly attenuated the ketamine-induced impairment, consistent with reports from clinical trials suggesting that nicotinic α7 receptor agonism has pro-cognitive potential in clinical populations. In contrast, pretreatment with the acetylcholinesterase inhibitor donepezil failed to reverse the ketamine-induced impairment, consistent with studies showing a lack of pro-cognitive effects in patients with schizophrenia. These data suggest that the ketamine-impaired object retrieval-detour task could provide a model with improved predictive validity for drug development, and confirm the need for additional efforts in back-translation. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
Asunto(s)
Compuestos de Bencilideno/uso terapéutico , Trastornos del Conocimiento/prevención & control , Modelos Animales de Enfermedad , Agonistas Nicotínicos/uso terapéutico , Nootrópicos/uso terapéutico , Piridinas/uso terapéutico , Receptores Nicotínicos/metabolismo , Esquizofrenia/tratamiento farmacológico , Animales , Conducta Animal/efectos de los fármacos , Inhibidores de la Colinesterasa/efectos adversos , Inhibidores de la Colinesterasa/uso terapéutico , Cognición/efectos de los fármacos , Trastornos del Conocimiento/etiología , Donepezilo , Evaluación Preclínica de Medicamentos/métodos , Antagonistas de Aminoácidos Excitadores , Indanos/efectos adversos , Indanos/uso terapéutico , Ketamina , Macaca mulatta , Masculino , Terapia Molecular Dirigida , Agonistas Nicotínicos/efectos adversos , Nootrópicos/efectos adversos , Piperidinas/efectos adversos , Piperidinas/uso terapéutico , Desempeño Psicomotor/efectos de los fármacos , Receptores de N-Metil-D-Aspartato/antagonistas & inhibidores , Receptores Nicotínicos/química , Esquizofrenia/fisiopatología , Receptor Nicotínico de Acetilcolina alfa 7RESUMEN
Brain penetration of drugs which are subject to P-glycoprotein (Pgp)-mediated efflux is attenuated, as manifested by the fact that the cerebrospinal fluid concentration (C(CSF)), a good surrogate of the unbound brain concentration (C(ub)), is lower than the unbound plasma concentration (C(up)) for Pgp substrates. In rodents, the attenuation magnitude of brain penetration by Pgp-mediated efflux has been estimated by correlating the ratio of CSF to plasma exposures (C(CSF)/C(p)) with the unbound fraction in plasma (f(u)) upon the incorporation of the in vivo or in vitro Pgp-mediated efflux ratios (ERs). In the present work, we investigated the impact of Pgp-mediated efflux on C(CSF) in monkeys. Following intravenous administration to cisterna magna ported rhesus monkeys, the CSF and plasma concentrations were determined for 25 compounds from three discovery programs. We also evaluated their f(u) in rhesus plasma and ER in human and African green monkey MDR-transfected LLC-PK1 cells. These compounds varied significantly in the f(u) (0.025-0.73), and 24 out of 25 are considered Pgp substrates based on their appreciable directional transport (ER>2). The C(CSF)/C(p) was significantly lower than the corresponding f(u) (>or=3-fold) for 16 compounds regardless of a significant correlation (R(2)=0.59, p=4 x 10(-5)) when the C(CSF)/C(p) was plotted against the f(u). When the f(u) was normalized to the ER (f(u)/ER) the correlation was improved (R(2)=0.75, p=8 x 10(-8)). More importantly, only one compound showed the C(CSF)/C(p) that exceeded 3-fold of the normalized f(u). The results suggest that the impact of Pgp-mediated efflux in monkeys, similar to the case in rodents, is reasonably reflected by the gradient between the free concentrations in plasma and in CSF. Therefore, f(u) and Pgp ER may serve as useful measurements in estimating in vivo C(CSF)/C(p) ratios in monkeys, and potentially in humans.
Asunto(s)
Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/farmacología , Transporte Biológico/efectos de los fármacos , Barrera Hematoencefálica/fisiología , Encéfalo/efectos de los fármacos , Plasma/efectos de los fármacos , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/genética , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Animales , Transporte Biológico/fisiología , Proteínas Sanguíneas/metabolismo , Encéfalo/metabolismo , Células Cultivadas , Humanos , Macaca mulatta , Masculino , Peso Molecular , Compuestos Orgánicos/síntesis química , Compuestos Orgánicos/metabolismo , Plasma/química , TransfecciónRESUMEN
Replication of the human immunodeficiency virus (HIV) is dependent upon the enzyme HIV integrase (IN), one of three essential enzymes encoded in the viral genome. HIV-1 IN catalyzes the insertion of the proviral DNA into the host genome (strand transfer). HIV-1 IN therefore presents an attractive chemotherapeutic target for the treatment of HIV infection and AIDS that could provide patients and physicians with an additional option for treatment. Assays were developed to identify inhibitors of IN strand transfer. Diketoacid lead compounds were explored and developed into a variety of heterocyclic templates that are potent inhibitors of integrase strand transfer with suitable medicinal chemical properties for treating HIV infection and AIDS. The 1,6-naphthyridine L-870810 (Antiviral activity in cells IC(95) NHS = 102 nM, n=237), was shown to be efficacious in reducing viral RNA by 1.7 log units after doses of 400mg BID to HIV infected patients. Optimization of physical properties led to L-900564, an inhibitor of HIV IN that has excellent cell potency in the presence of protein (Antiviral activity in cells IC(95) NHS = 16 nM, n=15), excellent activity against mutants raised to HIV integrase inhibitors, and a very good pharmacokinetic profile.
Asunto(s)
Química Farmacéutica/métodos , Inhibidores de Integrasa VIH/química , Compuestos Heterocíclicos/uso terapéutico , Cetoácidos/uso terapéutico , Química Farmacéutica/historia , Inhibidores de Integrasa VIH/historia , Historia del Siglo XX , Historia del Siglo XXI , Humanos , Estructura Molecular , Relación Estructura-ActividadRESUMEN
A 1,6-naphthyridine inhibitor of HIV-1 integrase has been discovered with excellent inhibitory activity in cells, good pharmacokinetics, and an excellent ability to inhibit virus with mutant enzyme.
Asunto(s)
Inhibidores de Integrasa VIH/síntesis química , Inhibidores de Integrasa VIH/farmacocinética , Naftiridinas/síntesis química , Administración Oral , Animales , Células Cultivadas , Integrasa de VIH/efectos de los fármacos , Integrasa de VIH/genética , Inhibidores de Integrasa VIH/farmacología , Humanos , Concentración 50 Inhibidora , Mutación , Naftiridinas/farmacocinética , Naftiridinas/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
The process of integrating the reverse-transcribed HIV-1 DNA into the host chromosomal DNA is catalyzed by the virally encoded enzyme integrase (IN). Integration requires two metal-dependent reactions, 3' end processing and strand transfer. Compounds that contain a diketo acid moiety have been shown to selectively inhibit the strand transfer reaction of IN in vitro and in infected cells and are effective as inhibitors of HIV-1 replication. To characterize the molecular basis of inhibition, we used functional assays and binding assays to evaluate a series of structurally related analogs. These studies focused on investigating the role of the conserved carboxylate and metal binding. We demonstrate that an acidic moiety such as a carboxylate or isosteric heterocycle is not required for binding to the enzyme complex but is essential for inhibition and confers distinct metal-dependent properties on the inhibitor. Binding requires divalent metal and resistance is metal dependent with active site mutants displaying resistance only when the enzymes are evaluated in the context of Mg(2+). The mechanism of action of these inhibitors is therefore likely a consequence of the interaction between the acid moiety and metal ion(s) in the IN active site, resulting in a functional sequestration of the critical metal cofactor(s). These studies thus have implications for modeling active site inhibitors of IN, designing and evaluating analogs with improved efficacy, and identifying inhibitors of other metal-dependent phosphotransferases.
Asunto(s)
Fármacos Anti-VIH/química , Inhibidores de Integrasa VIH/química , Integrasa de VIH/química , VIH-1/enzimología , Fármacos Anti-VIH/farmacología , Unión Competitiva , Integrasa de VIH/efectos de los fármacos , Inhibidores de Integrasa VIH/farmacología , Duplicado del Terminal Largo de VIH , Humanos , Ligandos , Magnesio , Manganeso , Modelos Químicos , Estructura Molecular , Fosfotransferasas/química , Estreptavidina , EstirenosRESUMEN
The increasing incidence of resistance to current HIV-1 therapy underscores the need to develop antiretroviral agents with new mechanisms of action. Integrase, one of three viral enzymes essential for HIV-1 replication, presents an important yet unexploited opportunity for drug development. We describe here the identification and characterization of L-870,810, a small-molecule inhibitor of HIV-1 integrase with potent antiviral activity in cell culture and good pharmacokinetic properties. L-870,810 is an inhibitor with an 8-hydroxy-(1,6)-naphthyridine-7-carboxamide pharmacophore. The compound inhibits HIV-1 integrase-mediated strand transfer, and its antiviral activity in vitro is a direct consequence of this ascribed effect on integration. L-870,810 is mechanistically identical to previously described inhibitors from the diketo acid series; however, viruses selected for resistance to L-870,810 contain mutations (integrase residues 72, 121, and 125) that uniquely confer resistance to the naphthyridine. Conversely, mutations associated with resistance to the diketo acid do not engender naphthyridine resistance. Importantly, the mutations associated with resistance to each of these inhibitors map to distinct regions within the integrase active site. Therefore, we propose a model of the two inhibitors that is consistent with this observation and suggests specific interactions with discrete binding sites for each ligand. These studies provide a structural basis and rationale for developing integrase inhibitors with the potential for unique and nonoverlapping resistance profiles.