RESUMO
Nucleos(t)ide analog therapy blocks DNA synthesis by the hepatitis B virus (HBV) reverse transcriptase and can control the infection, but treatment is life-long and has high costs and unpredictable long-term side effects. The profound suppression of HBV by the nucleos(t)ide analogs and their ability to cure some patients indicates that they can push HBV to the brink of extinction. Consequently, more patients could be cured by suppressing HBV replication further using a new drug in combination with the nucleos(t)ide analogs. The HBV ribonuclease H (RNAseH) is a logical drug target because it is the second of only two viral enzymes that are essential for viral replication, but it has not been exploited, primarily because it is very difficult to produce active enzyme. To address this difficulty, we expressed HBV genotype D and H RNAseHs in E. coli and enriched the enzymes by nickel-affinity chromatography. HBV RNAseH activity in the enriched lysates was characterized in preparation for drug screening. Twenty-one candidate HBV RNAseH inhibitors were identified using chemical structure-activity analyses based on inhibitors of the HIV RNAseH and integrase. Twelve anti-RNAseH and anti-integrase compounds inhibited the HBV RNAseH at 10 µM, the best compounds had low micromolar IC(50) values against the RNAseH, and one compound inhibited HBV replication in tissue culture at 10 µM. Recombinant HBV genotype D RNAseH was more sensitive to inhibition than genotype H. This study demonstrates that recombinant HBV RNAseH suitable for low-throughput antiviral drug screening has been produced. The high percentage of compounds developed against the HIV RNAseH and integrase that were active against the HBV RNAseH indicates that the extensive drug design efforts against these HIV enzymes can guide anti-HBV RNAseH drug discovery. Finally, differential inhibition of HBV genotype D and H RNAseHs indicates that viral genetic variability will be a factor during drug development.
Assuntos
Antivirais/farmacologia , Desenho de Fármacos , Vírus da Hepatite B/enzimologia , Terapia de Alvo Molecular/métodos , Ribonuclease H do Vírus da Imunodeficiência Humana/antagonistas & inibidores , Avaliação Pré-Clínica de Medicamentos , Genótipo , Inibidores de Integrase de HIV/farmacologia , Vírus da Hepatite B/efeitos dos fármacos , Vírus da Hepatite B/genética , Humanos , Técnicas In Vitro , Proteínas Recombinantes , Carga Viral , Replicação Viral/efeitos dos fármacos , Replicação Viral/fisiologiaRESUMO
We describe efforts to improve the pharmacokinetic profile of the aminopyridopyrazinone class of PDE5 inhibitors. These efforts led to the discovery of 3-[(trans-4-hydroxycyclohexyl)amino]-7-(6-methoxypyridin-3-yl)-1-(2-propoxyethyl)pyrido[3,4-b]pyrazin-2(1H)-one, a potent and selective inhibitor of PDE5 with an excellent PK profile.
Assuntos
Inibidores da Fosfodiesterase 5 , Inibidores de Fosfodiesterase/química , Pirazinas/química , Piridinas/química , Animais , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/metabolismo , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/antagonistas & inibidores , Nucleotídeo Cíclico Fosfodiesterase do Tipo 6/metabolismo , Cães , Descoberta de Drogas , Humanos , Inibidores de Fosfodiesterase/síntese química , Inibidores de Fosfodiesterase/farmacocinética , Isoformas de Proteínas/antagonistas & inibidores , Isoformas de Proteínas/metabolismo , Pirazinas/síntese química , Pirazinas/farmacocinética , Piridinas/síntese química , Piridinas/farmacocinética , Ratos , Ratos Endogâmicos SHR , Relação Estrutura-AtividadeRESUMO
Efforts to improve the potency and physical properties of the aminopyridiopyrazinone class of PDE5 inhibitors through modification of the core ring system are described. Five new ring systems are evaluated and features that impart improved potency and improved solubility are delineated.
Assuntos
Aminopiridinas/síntese química , Inibidores da Fosfodiesterase 5 , Inibidores de Fosfodiesterase/síntese química , Pirazinas/síntese química , Administração Oral , Aminopiridinas/farmacologia , Animais , Química Farmacêutica/métodos , GMP Cíclico/química , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/química , Desenho de Fármacos , Humanos , Concentração de Íons de Hidrogênio , Hipertensão/tratamento farmacológico , Microssomos/efeitos dos fármacos , Modelos Químicos , Inibidores de Fosfodiesterase/farmacologia , Pirazinas/farmacologia , Ratos , Ratos Sprague-Dawley , SolubilidadeRESUMO
A novel alpha7 nAChR agonist, N-[(3R,5R)-1-azabicyclo[3.2.1]oct-3-yl]furo[2,3-c]pyridine-5-carboxamide (3a, PHA-709829), has been identified for the potential treatment of cognitive deficits in schizophrenia. The compound shows potent and selective alpha7 in vitro activity, excellent brain penetration, good rat oral bioavailability and robust in vivo efficacy in a rat auditory sensory gating model.
Assuntos
Compostos Azabicíclicos/farmacologia , Agonistas Nicotínicos/farmacologia , Piridinas/farmacologia , Receptores Nicotínicos/efeitos dos fármacos , Animais , Compostos Azabicíclicos/síntese química , Compostos Azabicíclicos/química , Benzamidas/farmacologia , Proteínas Sanguíneas/efeitos dos fármacos , Compostos Bicíclicos com Pontes/farmacologia , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Cães , Relação Dose-Resposta a Droga , Humanos , Camundongos , Microssomos Hepáticos/efeitos dos fármacos , Conformação Molecular , Agonistas Nicotínicos/síntese química , Agonistas Nicotínicos/química , Piridinas/síntese química , Piridinas/química , Quinuclidinas/farmacologia , Ratos , Receptores Muscarínicos/efeitos dos fármacos , Estereoisomerismo , Relação Estrutura-Atividade , Receptor Nicotínico de Acetilcolina alfa7RESUMO
p38α activation of multiple effectors may underlie the failure of global p38α inhibitors in clinical trials. A unique inhibitor (CDD-450) was developed that selectively blocked p38α activation of the proinflammatory kinase MK2 while sparing p38α activation of PRAK and ATF2. Next, the hypothesis that the p38α-MK2 complex mediates inflammasome priming cues was tested. CDD-450 had no effect on NLRP3 expression, but it decreased IL-1ß expression by promoting IL-1ß mRNA degradation. Thus, IL-1ß is regulated not only transcriptionally by NF-κB and posttranslationally by the inflammasomes but also posttranscriptionally by p38α-MK2. CDD-450 also accelerated TNF-α and IL-6 mRNA decay, inhibited inflammation in mice with cryopyrinopathy, and was as efficacious as global p38α inhibitors in attenuating arthritis in rats and cytokine expression by cells from patients with cryopyrinopathy and rheumatoid arthritis. These findings have clinical translation implications as CDD-450 offers the potential to avoid tachyphylaxis associated with global p38α inhibitors that may result from their inhibition of non-MK2 substrates involved in antiinflammatory and housekeeping responses.
Assuntos
Inflamassomos/metabolismo , Inflamação/patologia , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Proteína Quinase 14 Ativada por Mitógeno/antagonistas & inibidores , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Transdução de Sinais , Animais , Artrite/patologia , Osso e Ossos/patologia , Citocinas/biossíntese , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Articulações/patologia , Masculino , Camundongos , Proteína Quinase 14 Ativada por Mitógeno/metabolismo , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/metabolismo , Estabilidade de RNA , Ratos Endogâmicos LewRESUMO
N-[(3R)-1-Azabicyclo[2.2.2]oct-3-yl]furo[2,3-c]pyridine-5-carboxamide (14, PHA-543,613), a novel agonist of the alpha7 neuronal nicotinic acetylcholine receptor (alpha7 nAChR), has been identified as a potential treatment of cognitive deficits in schizophrenia. Compound 14 is a potent and selective alpha7 nAChR agonist with an excellent in vitro profile. The compound is characterized by rapid brain penetration and high oral bioavailability in rat and demonstrates in vivo efficacy in auditory sensory gating and, in an in vivo model to assess cognitive performance, novel object recognition.
Assuntos
Compostos Bicíclicos Heterocíclicos com Pontes/síntese química , Transtornos Cognitivos/tratamento farmacológico , Agonistas Nicotínicos/síntese química , Nootrópicos/síntese química , Quinuclidinas/síntese química , Receptores Nicotínicos/metabolismo , Esquizofrenia/tratamento farmacológico , Animais , Disponibilidade Biológica , Encéfalo/metabolismo , Compostos Bicíclicos Heterocíclicos com Pontes/química , Compostos Bicíclicos Heterocíclicos com Pontes/farmacologia , Estabilidade de Medicamentos , Canais de Potássio Éter-A-Go-Go/efeitos dos fármacos , Potenciais Evocados Auditivos/efeitos dos fármacos , Humanos , Técnicas In Vitro , Aprendizagem/efeitos dos fármacos , Masculino , Memória/efeitos dos fármacos , Microssomos Hepáticos/efeitos dos fármacos , Microssomos Hepáticos/metabolismo , Neurônios/efeitos dos fármacos , Neurônios/fisiologia , Agonistas Nicotínicos/farmacocinética , Agonistas Nicotínicos/farmacologia , Nootrópicos/farmacocinética , Nootrópicos/farmacologia , Técnicas de Patch-Clamp , Quinuclidinas/química , Quinuclidinas/farmacologia , Ensaio Radioligante , Ratos , Ratos Sprague-Dawley , Receptores Nicotínicos/fisiologia , Reconhecimento Psicológico/efeitos dos fármacos , Estereoisomerismo , Relação Estrutura-Atividade , Receptor Nicotínico de Acetilcolina alfa7RESUMO
Given the threat of drug resistance, there is an acute need for new classes of antimalarial agents that act via a unique mechanism of action relative to currently used drugs. We have identified a set of druglike compounds within the Tres Cantos Anti-Malarial Set (TCAMS) which likely act via inhibition of a Plasmodium aspartic protease. Structure-activity relationship analysis and optimization of these aminohydantoins demonstrate that these compounds are potent nanomolar inhibitors of the Plasmodium aspartic proteases PM-II and PM-IV and likely one or more other Plasmodium aspartic proteases. Incorporation of a bulky group, such as a cyclohexyl group, on the aminohydantion N-3 position gives enhanced antimalarial potency while reducing inhibition of human aspartic proteases such as BACE. We have identified compound 8p (CWHM-117) as a promising lead for optimization as an antimalarial drug with a low molecular weight, modest lipophilicity, oral bioavailability, and in vivo antimalarial activity in mice.
RESUMO
We recently described a novel series of aminopyridopyrazinones as PDE5 inhibitors. Efforts toward optimization of this series culminated in the identification of 3-[4-(2-hydroxyethyl)piperazin-1-yl]-7-(6-methoxypyridin-3-yl)-1-(2-propoxyethyl)pyrido[3,4-b]pyrazin-2(1H)-one, which possessed an excellent potency and selectivity profile and demonstrated robust in vivo blood pressure lowering in a spontaneously hypertensive rat (SHR) model. Furthermore, this compound is brain penetrant and will be a useful agent for evaluating the therapeutic potential of central inhibition of PDE5. This compound has recently entered clinical trials.
Assuntos
Encéfalo/metabolismo , Inibidores da Fosfodiesterase 5 , Inibidores de Fosfodiesterase/síntese química , Inibidores de Fosfodiesterase/farmacologia , Pirazinas/síntese química , Pirazinas/farmacologia , Piridinas/síntese química , Piridinas/farmacologia , Administração Oral , Animais , Disponibilidade Biológica , Pressão Sanguínea/efeitos dos fármacos , Nucleotídeo Cíclico Fosfodiesterase do Tipo 5/metabolismo , Relação Dose-Resposta a Droga , Desenho de Fármacos , Humanos , Masculino , Modelos Químicos , Estrutura Molecular , Inibidores de Fosfodiesterase/farmacocinética , Pirazinas/farmacocinética , Piridinas/farmacocinética , Ratos , Ratos Endogâmicos SHR , Ratos Sprague-DawleyRESUMO
A novel set of azabicyclic aryl amides have been identified as potent and selective agonists of the alpha7 nAChR. A two-pronged approach was taken to improve the potential hERG liability of previously disclosed alpha7 nAChR agonist, PNU-282,987, while maintaining the compound's other desirable pharmacological properties. The first approach involved further exploration of the aryl carboxylic acid fragment of PNU-282,987, while the second approach focused on modification of the azabicyclic amine portion of PNU-282,987. The best compounds from each series are characterized by rapid brain penetration, good oral bioavailability in rat, and demonstrate in vivo efficacy in a rat P50 auditory sensory gating assay. At least one analog from each series (1h, 1o, 2a, 9a, and 18a) shows an improved hERG safety profile over PNU-282,987.
Assuntos
Encéfalo/metabolismo , Desenho de Fármacos , Agonistas Nicotínicos/farmacologia , Receptores Nicotínicos/química , Animais , Bungarotoxinas , Células Cultivadas , Eletrofisiologia , Potenciais Evocados Auditivos/efeitos dos fármacos , Hipocampo/efeitos dos fármacos , Ativação do Canal Iônico/efeitos dos fármacos , Estrutura Molecular , Atividade Motora/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Agonistas Nicotínicos/síntese química , Agonistas Nicotínicos/química , Técnicas de Patch-Clamp , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Sinapses/efeitos dos fármacos , Sinapses/fisiologia , Receptor Nicotínico de Acetilcolina alfa7RESUMO
In bacteria the biosynthesis of all nascent polypeptides begins with N-formylmethionine. The post-translational removal of the N-formyl group is carried out by peptide deformylase (PDF). Processing of the N-formyl group from critical bacterial proteins is required for cell survival. This formylation/deformylation cycle is unique to eubacteria and is not utilized in eucaryotic cytosolic protein biosynthesis. Thus, inhibition of PDF would halt bacterial growth, spare host cell-function, and would be a novel mechanism for a new class of antibiotic. Diffraction-quality Se-met crystals of S. aureus PDF were prepared that belong to space group C222(1) with unit cell parameters of a = 94.1 b = 121.9 c = 47.6 A. Multiple anomalous dispersion data were collected at the Advanced Photon Source 17-ID beamline and used to solve the PDF structure to 1.9 A resolution. Crystals were also prepared with three PDF inhibitors: thiorphan, actinonin and PNU-172550. The thiorphan and actinonin co-crystals belong to space group C222(1) with similar unit-cell dimensions. Repeated attempts to generate a complex structure of PDF with PNU-172550 from the orthorhombic space group were unsuccessful. Crystallization screening identified an alternate C2 crystal form with unit-cell dimensions of a = 93.4 b = 42.5 c = 104.1 A, beta = 93 degrees.