RESUMEN
O-GlcNAcylation is a post-translational modification of tau understood to lower the speed and yield of its aggregation, a pathological hallmark of Alzheimer's disease (AD). O-GlcNAcase (OGA) is the only enzyme that removes O-linked N-acetyl-d-glucosamine (O-GlcNAc) from target proteins. Therefore, inhibition of OGA represents a potential approach for the treatment of AD by preserving the O-GlcNAcylated tau protein. Herein, we report the multifactorial optimization of high-throughput screening hit 8 to a potent, metabolically stable, and orally bioavailable diazaspirononane OGA inhibitor (+)-56. The human OGA X-ray crystal structure has been recently solved, but bacterial hydrolases are still widely used as structural homologues. For the first time, we reveal how a nonsaccharide series of inhibitors binds bacterial OGA and discuss the suitability of two different bacterial orthologues as surrogates for human OGA. These breakthroughs enabled structure-activity relationships to be understood and provided context and boundaries for the optimization of druglike properties.
Asunto(s)
Compuestos Aza/farmacología , Inhibidores Enzimáticos/farmacología , Enfermedades Neurodegenerativas/tratamiento farmacológico , beta-N-Acetilhexosaminidasas/antagonistas & inhibidores , beta-N-Acetilhexosaminidasas/metabolismo , Animales , Compuestos Aza/química , Catálisis , Inhibidores Enzimáticos/química , Humanos , Masculino , Ratones , Ratones Endogámicos C57BL , Modelos Moleculares , Estructura Molecular , Mutagénesis , Relación Estructura-ActividadRESUMEN
We describe the hit-to-lead exploration of a [1,2,4]triazolo[1,5-a]pyrimidine phosphodiesterase 2A (PDE2A) inhibitor arising from high-throughput screening. X-ray crystallography enabled structure-guided design, leading to the identification of preferred substructural components. Further rounds of optimization used relative binding free-energy calculations to prioritize different substituents from the large accessible chemical space. The free-energy perturbation (FEP) calculations were performed for 265 putative PDE2A inhibitors, and 100 compounds were synthesized representing a relatively large prospective application providing unexpectedly active molecules with IC50's from 2340 to 0.89 nM. Lead compound 46 originating from the FEP calculations showed PDE2A inhibition IC50 of 1.3 ± 0.39 nM, â¼100-fold selectivity versus other PDE enzymes, clean cytochrome P450 profile, in vivo target occupancy, and promise for further lead optimization.
Asunto(s)
Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/antagonistas & inhibidores , Inhibidores de Fosfodiesterasa/química , Pirimidinas/química , Triazoles/química , Animales , Sitios de Unión , Encéfalo/metabolismo , Cristalografía por Rayos X , Fosfodiesterasas de Nucleótidos Cíclicos Tipo 2/metabolismo , Diseño de Fármacos , Semivida , Humanos , Concentración 50 Inhibidora , Isoenzimas/antagonistas & inhibidores , Isoenzimas/metabolismo , Masculino , Microsomas Hepáticos/metabolismo , Simulación del Acoplamiento Molecular , Inhibidores de Fosfodiesterasa/metabolismo , Inhibidores de Fosfodiesterasa/farmacocinética , Pirimidinas/metabolismo , Pirimidinas/farmacocinética , Ratas , Ratas Wistar , Estereoisomerismo , Relación Estructura-Actividad , Termodinámica , Triazoles/metabolismo , Triazoles/farmacocinéticaRESUMEN
The metabotropic glutamate subtypeâ 2 (mGlu2 ) receptor is a presynaptic membrane receptor distributed widely in brain that provides feedback inhibitory control of glutamate release. Inhibition of the mGlu2 receptor function with a negative allosteric modulator (NAM) enhances activity-dependent glutamate release, which may be of therapeutic benefit for the treatment of neurological and psychiatric disorders. An attractive pyrazole hit was identified after a high-throughput screening (HTS) campaign. The evolution of this hit is described by structure-activity relationship (SAR) studies on specific parts of the molecule. From near micromolar potency we could obtain compounds with single-digit nanomolar activity in the mGlu2 NAM GTPγS assay. In addition to SAR on inâ vitro potency, a more detailed overview is given with a specific set of compounds on the excellent agreement between inâ vitro potency, free brain concentration, and exâ vivo mGlu2 receptor occupancy. Finally, to obtain improved drug-like compounds, plans for future research are suggested toward increasing free brain concentration while maintaining high inâ vitro potency.
Asunto(s)
Pirazoles/farmacología , Receptores de Glutamato Metabotrópico/química , Receptores de Glutamato Metabotrópico/metabolismo , Regulación Alostérica/efectos de los fármacos , Animales , Línea Celular , Relación Dosis-Respuesta a Droga , Células HEK293 , Humanos , Microsomas Hepáticos/química , Microsomas Hepáticos/metabolismo , Estructura Molecular , Permeabilidad/efectos de los fármacos , Pirazoles/química , Ratas , Relación Estructura-ActividadRESUMEN
Positive allosteric modulators of the metabotropic glutamate 2 receptor have generated great interest in the past decade. There is mounting evidence of their potential as therapeutic agents in the treatment of multiple central nervous system disorders. We have previously reported substantial efforts leading to potent and selective mGlu2 PAMs. However, finding compounds with the optimal combination of in vitro potency and good druglike properties has remained elusive, in part because of the hydrophobic nature of the allosteric binding site. Herein, we report on the lead optimization process to overcome the poor solubility inherent to the advanced lead 6. Initial prototypes already showed significant improvements in solubility while retaining good functional activity but displayed new liabilities associated with metabolism and hERG inhibition. Subsequent subtle modifications efficiently addressed those issues leading to the identification of compound 27 (JNJ-46356479). This new lead represents a more balanced profile that offers a significant improvement on the druglike attributes compared to previously reported leads.
Asunto(s)
Piridinas/química , Piridinas/farmacología , Receptores de Glutamato Metabotrópico/agonistas , Triazoles/química , Triazoles/farmacología , Administración Oral , Regulación Alostérica/efectos de los fármacos , Animales , Células CHO , Células CACO-2 , Cricetulus , Perros , Humanos , Masculino , Modelos Moleculares , Piridinas/administración & dosificación , Piridinas/farmacocinética , Ratas , Receptores de Glutamato Metabotrópico/metabolismo , Triazoles/administración & dosificación , Triazoles/farmacocinéticaRESUMEN
A novel series of pyrido[4,3-e][1,2,4]triazolo[4,3-a]pyrazines is reported as potent PDE2/PDE10 inhibitors with drug-like properties. Selectivity for PDE2 was obtained by introducing a linear, lipophilic moiety on the meta-position of the phenyl ring pending from the triazole. The SAR and protein flexibility were explored with free energy perturbation calculations. Rat pharmacokinetic data and in vivo receptor occupancy data are given for two representative compounds 6 and 12.
RESUMEN
We report the continuation of a focused medicinal chemistry program aimed to further optimize a series of imidazo[1,2-a]pyrazines as a novel class of potent and selective phosphodiesterase 10A (PDE10A) inhibitors. In vitro and in vivo pharmacokinetic and pharmacodynamic evaluation allowed the selection of compound 25a for its assessment in preclinical models of psychosis. The evolution of our medicinal chemistry program, structure-activity relationship (SAR) analysis, as well as a detailed pharmacological profile for optimized lead 25a are described.
Asunto(s)
Inhibidores de Fosfodiesterasa/síntesis química , Hidrolasas Diéster Fosfóricas , Administración Oral , Animales , Disponibilidad Biológica , Modelos Animales de Enfermedad , Inhibidores de Fosfodiesterasa/farmacología , Inhibidores de Fosfodiesterasa/uso terapéutico , Ratas , Ratas Wistar , Esquizofrenia/tratamiento farmacológico , Relación Estructura-ActividadRESUMEN
We report the discovery of a series of imidazo[1,2-a]pyrazine derivatives as novel inhibitors of phosphodiesterase 10A (PDE10A). In a high-throughput screening campaign we identified the imidazopyrazine derivative 1, a PDE10A inhibitor with limited selectivity versus the other phosphodiesterases (PDEs). Subsequent investigation of 1 and replacement of the trimethoxyphenyl group by a (methoxyethyl)pyrazole moiety maintained PDE10A inhibition but enhanced selectivity against the other PDEs. Systematic examination and analysis of structure-activity and structure-property relationships resulted in the discovery of 2, an in vitro potent and selective inhibitor of PDE10A with high striatal occupancy of PDE10A, promising in vivo efficacy in different rodent behavioral models of schizophrenia, and a good pharmacokinetic profile in rats.
Asunto(s)
Inhibidores de Fosfodiesterasa/síntesis química , Hidrolasas Diéster Fosfóricas/efectos de los fármacos , Esquizofrenia/tratamiento farmacológico , Administración Oral , Animales , Descubrimiento de Drogas , Ensayos Analíticos de Alto Rendimiento , Inhibidores de Fosfodiesterasa/farmacología , Inhibidores de Fosfodiesterasa/uso terapéutico , Ratas , Relación Estructura-ActividadRESUMEN
The new phosphodiesterase 10A inhibitor (PDE10AI) JNJ-42314415 [3-[6-(2-methoxyethyl)pyridin-3-yl]-2-methyl-8-morpholin-4-ylimidazo[1,2-a]pyrazine] was compared with three reference PDE10AIs and eight dopamine 2 (D(2)) receptor blockers. Despite displaying relatively low PDE10A activity in vitro, JNJ-42314415 was found to be a relatively potent and specific PDE10AI in vivo. The compound was devoid of effects on prolactin release and of receptor interactions associated with other commonly observed adverse effects of available antipsychotics. Similar to D(2) receptor blockers, the tested PDE10AIs antagonized stimulant-induced behavior and inhibited conditioned avoidance behavior; these effects were observed at doses close to the ED(50) for striatal PDE10A occupancy. Relative to the ED(50) for inhibition of apomorphine-induced stereotypy, PDE10AIs blocked conditioned avoidance behavior and behaviors induced by nondopaminergic stimulants (phencyclidine, scopolamine) more efficiently than did D(2) receptor blockers; however, they blocked behaviors induced by dopaminergic stimulants (apomorphine, d-amphetamine) less efficiently. PDE10AIs also induced less pronounced catalepsy than D(2) receptor blockers. The effects of PDE10A inhibition against dopaminergic stimulants and on catalepsy were potentiated by the D(1) antagonist SCH-23390 (8-chloro-3-methyl-5-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepin-7-ol), suggesting that enhancement of D(1) receptor-mediated neurotransmission contributes to the behavioral profile of PDE10AIs. By reducing dopamine D(2) and concomitantly potentiating dopamine D(1) receptor-mediated neurotransmission, PDE10AIs may show antipsychotic activity with an improved side-effect profile relative to D(2) receptor blockers. However, the clinical implications of this dual mechanism must be further explored.
Asunto(s)
Antipsicóticos/farmacología , Antagonistas de Dopamina/farmacología , Antagonistas de los Receptores de Dopamina D2 , Imidazoles/farmacología , Inhibidores de Fosfodiesterasa/farmacología , Hidrolasas Diéster Fosfóricas/metabolismo , Pirazinas/farmacología , Animales , Antipsicóticos/química , Conducta Animal/efectos de los fármacos , Encéfalo/efectos de los fármacos , Encéfalo/metabolismo , Antagonistas de Dopamina/química , Femenino , Cobayas , Humanos , Masculino , Actividad Motora/efectos de los fármacos , Inhibidores de Fosfodiesterasa/química , Hidrolasas Diéster Fosfóricas/genética , Prolactina/metabolismo , Unión Proteica , Ratas , Ratas Endogámicas Lew , Ratas Sprague-Dawley , Ratas Wistar , Células Sf9 , Spodoptera , Conducta Estereotipada/efectos de los fármacosRESUMEN
A homology model of the active site region of tripeptidyl peptidase II (TPP II) was constructed based on the crystal structures of four subtilisin-like templates. The resulting model was subsequently validated by judging expectations of the model versus observed activities for a broad set of prepared TPP II inhibitors. The structure-activity relationships observed for the prepared TPP II inhibitors correlated nicely with the structural details of the TPP II active site model, supporting the validity of this model and its usefulness for structure-based drug design and pharmacophore searching experiments.
Asunto(s)
Serina Endopeptidasas/química , Secuencia de Aminoácidos , Aminopeptidasas , Dominio Catalítico , Gráficos por Computador , Simulación por Computador , Dipeptidil-Peptidasas y Tripeptidil-Peptidasas , Diseño de Fármacos , Técnicas In Vitro , Modelos Moleculares , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Serina Endopeptidasas/genética , Serina Endopeptidasas/metabolismo , Inhibidores de Serina Proteinasa/química , Inhibidores de Serina Proteinasa/farmacología , Sincalida/metabolismo , Relación Estructura-Actividad , TermodinámicaRESUMEN
We examined the pharmacological profile of (3,4-dihydro-2H-pyrano[2,3]b quinolin-7-yl) (cis-4-methoxycyclohexyl) methanone (JNJ16259685). At recombinant rat and human metabotropic glutamate (mGlu) 1a receptors, JNJ16259685 non-competitively inhibited glutamate-induced Ca2+ mobilization with IC50 values of 3.24+/-1.00 and 1.21+/-0.53 nM, respectively, while showing a much lower potency at the rat and human mGlu5a receptor. JNJ16259685 inhibited [3H]1-(3,4-dihydro-2H-pyrano[2,3-b]quinolin-7-yl)-2-phenyl-1-ethanone ([3H]R214127) binding to membranes prepared from cells expressing rat mGlu1a receptors with a Ki of 0.34+/-0.20 nM. JNJ16259685 showed no agonist, antagonist or positive allosteric activity toward rat mGlu2, -3, -4 or -6 receptors at concentrations up to 10 microM and did not bind to AMPA or NMDA receptors, or to a battery of other neurotransmitter receptors, ion channels and transporters. In primary cerebellar cultures, JNJ16259685 inhibited glutamate-mediated inositol phosphate production with an IC50 of 1.73+/-0.40 nM. Subcutaneously administered JNJ16259685 exhibited high potencies in occupying central mGlu1 receptors in the rat cerebellum and thalamus ( ED50=0.040 and 0.014 mg/kg, respectively). These data show that JNJ16259685 is a selective mGlu1 receptor antagonist with excellent potencies in inhibiting mGlu1 receptor function and binding and in occupying the mGlu1 receptor after systemic administration.
Asunto(s)
Antagonistas de Aminoácidos Excitadores/farmacología , Quinolinas/farmacología , Receptores AMPA/antagonistas & inhibidores , Animales , Autorradiografía , Células CHO , Células Cultivadas , Cerebelo/citología , Cerebelo/efectos de los fármacos , Cricetinae , Relación Dosis-Respuesta a Droga , Femenino , Guanosina 5'-O-(3-Tiotrifosfato)/farmacología , Humanos , Fosfatos de Inositol/metabolismo , Masculino , Piranos/farmacología , Ratas , Ratas Wistar , Receptores AMPA/genética , Proteínas Recombinantes/efectos de los fármacos , Tetrahidrofolato Deshidrogenasa/deficiencia , TransfecciónRESUMEN
This communication describes the synthesis and in vitro PDE4 inhibitory activity of a novel series of imidazol-2-one and 2-cyanoiminoimidazole derivatives. The compounds described were also tested in in vivo models to evaluate their anti-inflammatory activity after topical administration as well as their gastro-intestinal side effects. Several compounds proved to be potent PDE4 inhibitors and some 2-cyanoiminoimidazoles showed less pronounced gastro-intestinal side effects than reference compounds but maintained anti-inflammatory activity after topical administration.