RESUMEN
Biased agonists, which selectively stimulate certain signaling pathways controlled by a G protein-coupled receptor (GPCR), hold great promise as drugs that maximize efficacy while minimizing dangerous side effects. Biased agonists of the µ-opioid receptor (µOR) are of particular interest as a means to achieve analgesia through G protein signaling without dose-limiting side effects such as respiratory depression and constipation. Rational structure-based design of biased agonists remains highly challenging, however, because the ligand-mediated interactions that are key to activation of each signaling pathway remain unclear. We identify several compounds for which the R- and S-enantiomers have distinct bias profiles at the µOR. These compounds serve as excellent comparative tools to study bias because the identical physicochemical properties of enantiomer pairs ensure that differences in bias profiles are due to differences in interactions with the µOR binding pocket. Atomic-level simulations of compounds at µOR indicate that R- and S-enantiomers adopt different poses that form distinct interactions with the binding pocket. A handful of specific interactions with highly conserved binding pocket residues appear to be responsible for substantial differences in arrestin recruitment between enantiomers. Our results offer guidance for rational design of biased agonists at µOR and possibly at related GPCRs.
Asunto(s)
Receptores Opioides mu , Transducción de Señal , Proteínas de Unión al GTP , Humanos , Ligandos , Dolor , Unión Proteica , Receptores Opioides mu/metabolismoRESUMEN
The design, optimization, and evaluation of a series of novel imidazopyridazine-based subtype-selective positive allosteric modulators (PAMs) for the GABAA ligand-gated ion channel are described. From a set of initial hits multiple subseries were designed and evaluated based on binding affinity and functional activity. As designing in the desired level of functional selectivity proved difficult, a probability-based assessment was performed to focus the project's efforts on a single subseries that had the greatest odds of delivering the target profile. These efforts ultimately led to the identification of two precandidates from this subseries, which were advanced to preclinical safety studies and subsequently to the identification of the clinical candidate PF-06372865.
Asunto(s)
Diseño de Fármacos , Imidazoles/farmacología , Piridazinas/farmacología , Receptores de GABA-A/metabolismo , Regulación Alostérica/efectos de los fármacos , Humanos , Imidazoles/química , Piridazinas/químicaRESUMEN
Tropomyosin receptor kinases (TrkA, TrkB, TrkC) are activated by hormones of the neurotrophin family: nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), and neurotrophin 4 (NT4). Moreover, the NGF antibody tanezumab has provided clinical proof of concept for inhibition of the TrkA kinase pathway in pain leading to significant interest in the development of small molecule inhibitors of TrkA. However, achieving TrkA subtype selectivity over TrkB and TrkC via a Type I and Type II inhibitor binding mode has proven challenging and Type III or Type IV allosteric inhibitors may present a more promising selectivity design approach. Furthermore, TrkA inhibitors with minimal brain availability are required to deliver an appropriate safety profile. Herein, we describe the discovery of a highly potent, subtype selective, peripherally restricted, efficacious, and well-tolerated series of allosteric TrkA inhibitors that culminated in the delivery of candidate quality compound 23.
Asunto(s)
Inhibidores de Proteínas Quinasas/química , Receptor trkA/antagonistas & inhibidores , Regulación Alostérica , Secuencia de Aminoácidos , Animales , Sitios de Unión , Cristalografía por Rayos X , Evaluación Preclínica de Medicamentos , Semivida , Ensayos Analíticos de Alto Rendimiento , Humanos , Ligandos , Microsomas Hepáticos/metabolismo , Simulación de Dinámica Molecular , Unión Proteica , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Inhibidores de Proteínas Quinasas/síntesis química , Inhibidores de Proteínas Quinasas/farmacocinética , Estructura Terciaria de Proteína , Pirazoles/síntesis química , Pirazoles/química , Pirazoles/farmacocinética , Ratas , Receptor trkA/metabolismo , Alineación de Secuencia , Relación Estructura-ActividadRESUMEN
The voltage gated sodium channel NaV1.8 has been postulated to play a key role in the transmission of pain signals. Core hopping from our previously reported phenylimidazole leads has allowed the identification of a novel series of benzimidazole NaV1.8 blockers. Subsequent optimization allowed the identification of compound 9, PF-06305591, as a potent, highly selective blocker with an excellent preclinical in vitro ADME and safety profile.
Asunto(s)
Bencimidazoles/farmacología , Canal de Sodio Activado por Voltaje NAV1.8/metabolismo , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacología , Bencimidazoles/síntesis química , Bencimidazoles/química , Bencimidazoles/farmacocinética , Diseño de Fármacos , Células HEK293 , Humanos , Estructura Molecular , Solubilidad , Relación Estructura-Actividad , Bloqueadores del Canal de Sodio Activado por Voltaje/síntesis química , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacocinéticaRESUMEN
Two chemotypes were examined in vitro with CYPs 3A4 and 2C19 by molecular docking, metabolic profiles, and intrinsic clearance deuterium isotope effects with specifically deuterated form to assess the potential for enhancement of pharmacokinetic parameters. The results show the complexity of deuteration as an approach for pharmacokinetic enhancement when CYP enzymes are involved in metabolic clearance. With CYP3A4 the rate limiting step was chemotype-dependent. With one chemotype no intrinsic clearance deuterium isotope effect was observed with any deuterated form, whereas with the other chemotype the rate limiting step was isotopically sensitive, and the magnitude of the intrinsic clearance isotope effect was dependent on the position(s) and extent of deuteration. Molecular docking and metabolic profiles aided in identifying sites for deuteration and predicted the possibility for metabolic switching. However, the potential for an isotope effect on the intrinsic clearance cannot be predicted and must be established by examining select deuterated versions of the chemotypes. The results show how in a deuteration strategy molecular docking, in-vitro metabolic profiles, and intrinsic clearance assessments with select deuterated versions of new chemical entities can be applied to determine the potential for pharmacokinetic enhancement in a discovery setting. They also help explain the substantial failures reported in the literature of deuterated versions of drugs to elicit a systemic enhancement on pharmacokinetic parameters.
Asunto(s)
Citocromo P-450 CYP2C19/química , Citocromo P-450 CYP3A/química , Deuterio/química , Farmacocinética , Citocromo P-450 CYP2C19/efectos de la radiación , Citocromo P-450 CYP3A/efectos de la radiación , Deuterio/farmacología , Hemo/química , Hemo/efectos de la radiación , Humanos , Inactivación Metabólica , Cinética , Microsomas/efectos de la radiación , Simulación del Acoplamiento Molecular , Oxidación-Reducción/efectos de la radiación , Especificidad por SustratoRESUMEN
The optimization of a new class of small molecule PCSK9 mRNA translation inhibitors is described. The potency, physicochemical properties, and off-target pharmacology associated with the hit compound (1) were improved by changes to two regions of the molecule. The last step in the synthesis of the congested amide center was enabled by three different routes. Subtle structural changes yielded significant changes in pharmacology and off-target margins. These efforts led to the identification of 7l and 7n with overall profiles suitable for in vivo evaluation. In a 14-day toxicology study, 7l demonstrated an improved safety profile vs lead 7f. We hypothesize that the improved safety profile is related to diminished binding of 7l to nontranslating ribosomes and an apparent improvement in transcript selectivity due to the lower strength of 7l stalling of off-target proteins.
Asunto(s)
Inhibidores de PCSK9 , Inhibidores de Proteasas/química , Inhibidores de Proteasas/farmacología , Animales , Diseño de Fármacos , Masculino , Inhibidores de Proteasas/efectos adversos , Inhibidores de Proteasas/metabolismo , Ratas , Ratas Sprague-Dawley , Seguridad , Relación Estructura-ActividadRESUMEN
Hormones of the neurotrophin family, nerve growth factor (NGF), brain derived neurotrophic factor (BDNF), neurotrophin 3 (NT3), and neurotrophin 4 (NT4), are known to activate the family of Tropomyosin receptor kinases (TrkA, TrkB, and TrkC). Moreover, inhibition of the TrkA kinase pathway in pain has been clinically validated by the NGF antibody tanezumab, leading to significant interest in the development of small molecule inhibitors of TrkA. Furthermore, Trk inhibitors having an acceptable safety profile will require minimal brain availability. Herein, we discuss the discovery of two potent, selective, peripherally restricted, efficacious, and well-tolerated series of pan-Trk inhibitors which successfully delivered three candidate quality compounds 10b, 13b, and 19. All three compounds are predicted to possess low metabolic clearance in human that does not proceed via aldehyde oxidase-catalyzed reactions, thus addressing the potential clearance prediction liability associated with our current pan-Trk development candidate PF-06273340.
Asunto(s)
Descubrimiento de Drogas , Dolor/tratamiento farmacológico , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Tirosina Quinasas Receptoras/antagonistas & inhibidores , Animales , Humanos , Ligandos , Simulación del Acoplamiento Molecular , Conformación Proteica , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacocinética , Inhibidores de Proteínas Quinasas/uso terapéutico , Piridinas/química , Piridinas/farmacocinética , Piridinas/farmacología , Piridinas/uso terapéutico , Ratas , Proteínas Tirosina Quinasas Receptoras/química , Proteínas Tirosina Quinasas Receptoras/metabolismo , Solubilidad , Relación Estructura-Actividad , Distribución TisularRESUMEN
The discovery and selection of a highly potent and selective NaV1.7 inhibitor PF-06456384, designed specifically for intravenous infusion, is disclosed. Extensive in vitro pharmacology and ADME profiling followed by in vivo preclinical PK and efficacy model data are discussed. A proposed protein-ligand binding mode for this compound is also provided to rationalise the high levels of potency and selectivity over inhibition of related sodium channels. To further support the proposed binding mode, potent conjugates are described which illustrate the potential for development of chemical probes to enable further target evaluation.
Asunto(s)
Canal de Sodio Activado por Voltaje NAV1.7/química , Piperidinas/química , Piridinas/química , Sulfonamidas/química , Bloqueadores del Canal de Sodio Activado por Voltaje/química , Animales , Sitios de Unión , Perros , Semivida , Hepatocitos/metabolismo , Humanos , Infusiones Intravenosas , Concentración 50 Inhibidora , Ratones , Microsomas Hepáticos/metabolismo , Simulación del Acoplamiento Molecular , Canal de Sodio Activado por Voltaje NAV1.7/metabolismo , Dolor/tratamiento farmacológico , Dolor/patología , Piperidinas/farmacocinética , Piperidinas/uso terapéutico , Unión Proteica , Estructura Terciaria de Proteína , Piridinas/farmacocinética , Piridinas/uso terapéutico , Ratas , Relación Estructura-Actividad , Sulfonamidas/farmacocinética , Sulfonamidas/uso terapéutico , Tiadiazoles , Bloqueadores del Canal de Sodio Activado por Voltaje/farmacocinética , Bloqueadores del Canal de Sodio Activado por Voltaje/uso terapéuticoRESUMEN
A series of TRPA1 antagonists is described which has as its core structure an indazole moiety. The physical properties and in vitro DMPK profiles are discussed. Good in vivo exposure was obtained with several analogs, allowing efficacy to be assessed in rodent models of inflammatory pain. Two compounds showed significant activity in these models when administered either systemically or topically. Protein chimeras were constructed to indicate compounds from the series bound in the S5 region of the channel, and a computational docking model was used to propose a binding mode for example compounds.
RESUMEN
A three-component, titanium-mediated synthesis of α-branched N-acylamines from commercial or readily accessible amides, aldehydes, and organometallic reagents is reported. The transformation proceeds under mild reaction conditions and tolerates a variety of functional groups (including nitrile, carbamate, olefin, basic amine, furan, and other sensitive heteroaromatics) to generate a large umbrella of α-branched N-acylamine products in high yields. The operationally practical procedure enables the use of this method in parallel chemical synthesis, a valuable feature that can facilitate the screening of bioactive molecules by medicinal chemists.
RESUMEN
Histone deacetylases (HDACs) contribute to regulation of gene expression by mediating higher-order chromatin structures. They assemble into large multiprotein complexes that regulate activity and specificity. We report the development of small molecule probes with class IIa and pan-HDAC activity that contain photoreactive crosslinking groups and either a biotin reporter, or a terminal alkyne handle for subsequent bioorthogonal ligation. The probes retained inhibitory activity against recombinant HDAC proteins and caused an accumulation of acetylated histone and tubulin following cell treatment. The versatility of the probes has been demonstrated by their ability to photoaffinity modify HDAC targets in vitro. An affinity enrichment probe was used in conjunction with mass spectrometry proteomics to isolate HDACs and their interacting proteins in a native proteome. The performance of the probes in recombinant versus cell-based systems highlights issues for the development of chemoproteomic technologies targeting class IIa HDACs in particular.
Asunto(s)
Inhibidores de Histona Desacetilasas/química , Histona Desacetilasas/química , Histona Desacetilasas/metabolismo , Sondas Moleculares/química , Proteómica , Acetilación , Permeabilidad de la Membrana Celular/efectos de los fármacos , Descubrimiento de Drogas , Activación Enzimática/efectos de los fármacos , Inhibidores de Histona Desacetilasas/farmacología , Humanos , Espectrometría de Masas , Sondas Moleculares/farmacología , Estructura Molecular , Proteoma , Proteómica/métodos , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , Coloración y EtiquetadoRESUMEN
Myeloperoxidase (MPO) is a heme peroxidase that catalyzes the production of hypochlorous acid. Clinical evidence suggests a causal role for MPO in various autoimmune and inflammatory disorders including vasculitis and cardiovascular and Parkinson's diseases, implying that MPO inhibitors may represent a therapeutic treatment option. Herein, we present the design, synthesis, and preclinical evaluation of N1-substituted-6-arylthiouracils as potent and selective inhibitors of MPO. Inhibition proceeded in a time-dependent manner by a covalent, irreversible mechanism, which was dependent upon MPO catalysis, consistent with mechanism-based inactivation. N1-Substituted-6-arylthiouracils exhibited low partition ratios and high selectivity for MPO over thyroid peroxidase and cytochrome P450 isoforms. N1-Substituted-6-arylthiouracils also demonstrated inhibition of MPO activity in lipopolysaccharide-stimulated human whole blood. Robust inhibition of plasma MPO activity was demonstrated with the lead compound 2-(6-(5-chloro-2-methoxyphenyl)-4-oxo-2-thioxo-3,4-dihydropyrimidin-1(2H)-yl)acetamide (PF-06282999, 8) upon oral administration to lipopolysaccharide-treated cynomolgus monkeys. On the basis of its pharmacological and pharmacokinetic profile, PF-06282999 has been advanced to first-in-human pharmacokinetic and safety studies.
Asunto(s)
Acetamidas/farmacología , Enfermedades Cardiovasculares/tratamiento farmacológico , Enfermedades Cardiovasculares/enzimología , Inhibidores Enzimáticos/farmacología , Peroxidasa/antagonistas & inhibidores , Pirimidinonas/farmacología , Acetamidas/química , Acetamidas/farmacocinética , Animales , Descubrimiento de Drogas , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacocinética , Humanos , Peroxidasa/metabolismo , Pirimidinonas/química , Pirimidinonas/farmacocinética , Ratas WistarRESUMEN
Here, we report accessing small 3-fluoropyrrolidines and 3,3-difluoropyrrolidines through a 1,3-dipolar cycloaddition with a simple azomethine ylide and a variety of vinyl fluorides and vinyl difluorides. We demonstrate that vinyl fluorides within α,ß-unsaturated, styrenyl and even enol ether systems can participate in the cycloaddition reaction. The vinyl fluorides are relatively easy to synthesize through a variety of methods, making the 3-fluoropyrrolidines very accessible.
Asunto(s)
Compuestos Azo/química , Pirrolidinas/síntesis química , Tiosemicarbazonas/química , Reacción de Cicloadición , Estructura Molecular , Pirrolidinas/química , EstereoisomerismoRESUMEN
Optimization of a high-throughput screening hit led to the discovery of a new series of 5-phenoxy-1,3-dimethyl-1H-pyrazole-4-carboxamides as highly potent agonists of TGR5. This novel chemotype was rapidly developed through iterative combinatorial library synthesis. It was determined that in vitro agonist potency correlated with functional activity data from human peripheral blood monocytes.
Asunto(s)
Amidas/síntesis química , Amidas/farmacología , Pirazoles/síntesis química , Pirazoles/farmacología , Receptores Acoplados a Proteínas G/agonistas , Amidas/química , Técnicas Químicas Combinatorias , Humanos , Pirazoles/química , Relación Estructura-ActividadRESUMEN
The addition of the SuperQuat enolate to five- and six-membered heterocyclic tert-butyl sulfinimines led to a high syn-selectivity of up to 99:1 in good to excellent yields. The reaction is tentatively proposed to proceed through an open-chain transition state with the presence of an α-heteroatom on the sulfinimine leading to high diastereoselectivities. The adducts were derivatized to ß-amino esters and amides in a facile manner.
Asunto(s)
Aminoácidos/síntesis química , Iminas/química , Compuestos de Sulfonio/química , Amidas/química , Aminoácidos/química , Técnicas Químicas Combinatorias , Estructura Molecular , EstereoisomerismoRESUMEN
Takeda G-protein-coupled receptor 5 (TGR5) represents an exciting biological target for the potential treatment of diabetes and metabolic syndrome. A new class of high-throughput screening (HTS)-derived tetrahydropyrido[4,3-d]pyrimidine amide TGR5 agonists is disclosed. We describe our effort to identify an orally available agonist suitable for assessment of systemic TGR5 agonism. This effort resulted in identification of 16, which had acceptable potency and pharmacokinetic properties to allow for in vivo assessment in dog. A key aspect of this work was the calibration of human and dog in vitro assay systems that could be linked with data from a human ex vivo peripheral blood monocyte assay that expresses receptor at endogenous levels. Potency from the human in vitro assay was also found to correlate with data from an ex vivo human whole blood assay. This calibration exercise provided confidence that 16 could be used to drive plasma exposures sufficient to test the effects of systemic activation of TGR5.
RESUMEN
Lipid A is an essential component of the Gram negative outer membrane, which protects the bacterium from attack of many antibiotics. The Lipid A biosynthesis pathway is essential for Gram negative bacterial growth and is unique to these bacteria. The first committed step in Lipid A biosynthesis is catalysis by LpxC, a zinc dependent deacetylase. We show the design of an LpxC inhibitor utilizing a robust model which directed efficient design of picomolar inhibitors. Analysis of physiochemical properties drove design to focus on an optimal lipophilicity profile. Further structure based design took advantage of a conserved water network over the active site, and with the optimal lipophilicity profile, led to an improved LpxC inhibitor with in vivo activity against wild type Pseudomonas aeruginosa.
Asunto(s)
Amidohidrolasas/química , Antibacterianos/síntesis química , Inhibidores Enzimáticos/síntesis química , Ácidos Hidroxámicos/síntesis química , Pseudomonas aeruginosa/efectos de los fármacos , Amidohidrolasas/antagonistas & inhibidores , Antibacterianos/farmacología , Dominio Catalítico , Diseño de Fármacos , Inhibidores Enzimáticos/farmacología , Interacciones Hidrofóbicas e Hidrofílicas , Ácidos Hidroxámicos/farmacología , Lípido A/metabolismo , Pruebas de Sensibilidad Microbiana , Modelos Moleculares , Unión Proteica , Pseudomonas aeruginosa/enzimología , Relación Estructura-Actividad , Agua/químicaRESUMEN
In this paper, we present the synthesis and SAR as well as selectivity, pharmacokinetic, and infection model data for representative analogues of a novel series of potent antibacterial LpxC inhibitors represented by hydroxamic acid.
Asunto(s)
Amidohidrolasas/antagonistas & inhibidores , Antibacterianos/síntesis química , Compuestos de Bifenilo/síntesis química , Ácidos Hidroxámicos/síntesis química , Éteres Fenílicos/síntesis química , Infecciones por Pseudomonas/tratamiento farmacológico , Sulfuros/síntesis química , Sulfonas/síntesis química , Animales , Antibacterianos/química , Antibacterianos/farmacología , Compuestos de Bifenilo/química , Compuestos de Bifenilo/farmacología , Dominio Catalítico , Cristalografía por Rayos X , Farmacorresistencia Bacteriana , Enlace de Hidrógeno , Ácidos Hidroxámicos/química , Ácidos Hidroxámicos/farmacología , Ratones , Modelos Moleculares , Conformación Molecular , Éteres Fenílicos/química , Éteres Fenílicos/farmacología , Pseudomonas aeruginosa , Ratas , Estereoisomerismo , Relación Estructura-Actividad , Sulfuros/química , Sulfuros/farmacología , Sulfonas/química , Sulfonas/farmacologíaRESUMEN
A series of acyloxyalkyl and amidooxyalkyl ketones appended to a carbobenzyloxy aspartic acid core have been prepared. The most potent of these new inhibitors was 4i with a K(i) of 0.5 microM. These two series provide an improved understanding of the binding requirements for the hydrophobic prime side of ICE.
Asunto(s)
Inhibidores de Caspasas , Inhibidores de Cisteína Proteinasa/farmacología , Cetonas/farmacología , Humanos , Modelos Moleculares , Monocitos/efectos de los fármacosRESUMEN
A series of benzyl phenyl ethers (BPEs) is described that displays potent inhibition of bacterial phenylalanyl-tRNA synthetase. The synthesis, SAR, and select ADMET data are provided.