RESUMO
Factor XI (FXI) is an integral component of the intrinsic pathway of the coagulation cascade and plays a critical role in thrombus formation. Because its role in the pathogenesis of cerebral microembolic signals (MES) is unclear, this study used a potent and selective small molecule inhibitor of FXIa, compound 1, to assess the effect of FXI blockade in our recently established preclinical model of cerebral MES induced by FeCl3 injury of the carotid artery in male New Zealand White rabbits. Ascending doses of compound 1 were evaluated simultaneously for both carotid arterial thrombosis by a Doppler flowmeter and MES in the middle cerebral artery by a transcranial Doppler. Plasma drug exposure and pharmacodynamic responses to compound 1 treatment were also assessed. The effective dose for 50% inhibition (ED50) of thrombus formation was 0.003 mg/kg/h compound 1, i.v. for the integrated blood flow, 0.004 mg/kg/h for reduction in thrombus weight, and 0.106 mg/kg/h for prevention of MES. The highest dose, 3 mg/kg/h compound 1, achieved complete inhibition in both thrombus formation and MES. In addition, we assessed the potential bleeding liability of compound 1 (5 mg/kg/h, i.v., >1250-fold ED50 levels in arterial thrombosis) in rabbits using a cuticle bleeding model, and observed about 2-fold (not statistically significant) prolongation in bleeding time. Our study demonstrates that compound 1 produced a robust and dose-dependent inhibition of both arterial thrombosis and MES, suggesting that FXIa blockade may represent a novel therapeutic strategy for the reduction in MES in patients at risk for ischemic stroke.
Assuntos
Anticoagulantes/farmacologia , Coagulação Sanguínea/efeitos dos fármacos , Trombose das Artérias Carótidas , Fator XIa/antagonistas & inibidores , Embolia Intracraniana , Animais , Coagulação Sanguínea/fisiologia , Trombose das Artérias Carótidas/sangue , Trombose das Artérias Carótidas/complicações , Trombose das Artérias Carótidas/diagnóstico por imagem , Trombose das Artérias Carótidas/tratamento farmacológico , Modelos Animais de Doenças , Desenho de Fármacos , Injeções Intravenosas , Embolia Intracraniana/sangue , Embolia Intracraniana/diagnóstico por imagem , Embolia Intracraniana/etiologia , Embolia Intracraniana/prevenção & controle , Masculino , Coelhos , Ultrassonografia Doppler Transcraniana/métodosRESUMO
Platensimycin (PTM) is a recently discovered broad-spectrum antibiotic produced by Streptomyces platensis. It acts by selectively inhibiting the elongation-condensing enzyme FabF of the fatty acid biosynthesis pathway in bacteria. We report here that PTM is also a potent and highly selective inhibitor of mammalian fatty acid synthase. In contrast to two agents, C75 and cerulenin, that are widely used as inhibitors of mammalian fatty acid synthase, platensimycin specifically inhibits fatty acid synthesis but not sterol synthesis in rat primary hepatocytes. PTM preferentially concentrates in liver when administered orally to mice and potently inhibits hepatic de novo lipogenesis, reduces fatty acid oxidation, and increases glucose oxidation. Chronic administration of platensimycin led to a net reduction in liver triglyceride levels and improved insulin sensitivity in db/+ mice fed a high-fructose diet. PTM also reduced ambient glucose levels in db/db mice. These results provide pharmacological proof of concept of inhibiting fatty acid synthase for the treatment of diabetes and related metabolic disorders in animal models.
Assuntos
Adamantano/uso terapêutico , Aminobenzoatos/uso terapêutico , Anilidas/uso terapêutico , Diabetes Mellitus/tratamento farmacológico , Ácido Graxo Sintases/antagonistas & inibidores , Fígado Gorduroso/tratamento farmacológico , Hipoglicemiantes/uso terapêutico , Animais , Anti-Infecciosos/uso terapêutico , Modelos Animais de Doenças , Ácidos Graxos/biossíntese , Glucose/metabolismo , Humanos , Fígado/metabolismo , Camundongos , Camundongos Mutantes , Oxirredução , Esteróis/biossínteseRESUMO
A new series of thiazole-substituted 1,1,1,3,3,3-hexafluoro-2-propanols were prepared and evaluated as malonyl-CoA decarboxylase (MCD) inhibitors. Key analogs caused dose-dependent decreases in food intake and body weight in obese mice. Acute treatment with these compounds also led to a drop in elevated blood glucose in a murine model of type II diabetes.
Assuntos
Fármacos Antiobesidade/uso terapêutico , Carboxiliases/antagonistas & inibidores , Diabetes Mellitus Tipo 2/tratamento farmacológico , Desenho de Fármacos , Hipoglicemiantes/uso terapêutico , Obesidade/tratamento farmacológico , Propanóis/uso terapêutico , Animais , Fármacos Antiobesidade/síntese química , Fármacos Antiobesidade/química , Fármacos Antiobesidade/farmacologia , Glicemia/efeitos dos fármacos , Peso Corporal/efeitos dos fármacos , Carboxiliases/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Humanos , Hipoglicemiantes/síntese química , Hipoglicemiantes/química , Hipoglicemiantes/farmacologia , Camundongos , Camundongos Endogâmicos C57BL , Propanóis/síntese química , Propanóis/química , Propanóis/farmacologia , Tiazóis/síntese química , Tiazóis/química , Tiazóis/farmacologia , Tiazóis/uso terapêuticoRESUMO
A potent and selective Factor IXa (FIXa) inhibitor was subjected to a series of liver microsomal incubations, which generated a number of metabolites. Using automated ligand identification system-affinity selection (ALIS-AS) methodology, metabolites in the incubation mixture were prioritized by their binding affinities to the FIXa protein. Microgram quantities of the metabolites of interest were then isolated through microisolation analytical capabilities, and structurally characterized using MicroCryoProbe heteronuclear 2D NMR techniques. The isolated metabolites recovered from the NMR experiments were then submitted directly to an in vitro FIXa enzymatic assay. The order of the metabolites' binding affinity to the Factor IXa protein from the ALIS assay was completely consistent with the enzymatic assay results. This work showcases an innovative and efficient approach to uncover structure-activity relationships (SARs) and guide drug design via microisolation-structural characterization and ALIS capabilities.
Assuntos
Automação , Desenho de Fármacos , Fator IXa/antagonistas & inibidores , Fibrinolíticos/farmacologia , Ressonância Magnética Nuclear Biomolecular , Animais , Relação Dose-Resposta a Droga , Fator IXa/metabolismo , Fibrinolíticos/química , Fibrinolíticos/metabolismo , Humanos , Ligantes , Estrutura Molecular , Ratos , Relação Estrutura-AtividadeRESUMO
Molecular modeling has been used to assist in the development of a novel series of potent glycogen phosphorylase inhibitors based on a phenyl diacid lead, compound 1. In the absence of suitable competitive binding assays, compound 1 was predicted to bind at the AMP allosteric site based on superposition onto known inhibitors which bind at different sites in the enzyme and analyses of the surrounding protein environment associated with these distinct sites. Possible docking modes of compound 1 at the AMP allosteric site were further explored using the crystal structure of rabbit muscle glycogen phosphorylase complexed with a Bayer diacid compound W1807 (PDB entry 3AMV). Compound 1 was predicted to interact with positively charged arginines at the AMP allosteric site in the docking model. Characterization of the binding pocket by a grid-based surface calculation of the docking model revealed a large unfilled hydrophobic region near the central phenyl ring, suggesting that compounds with larger hydrophobic groups in this region would improve binding. A series of naphthyl diacid compounds were designed and synthesized to access this hydrophobic cleft, and showed significantly improved potency.
Assuntos
Desenho Assistido por Computador , Desenho de Fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Monofosfato de Adenosina/metabolismo , Sítio Alostérico , Glicogênio Fosforilase/química , Glicogênio Fosforilase/metabolismo , Glicogênio Fosforilase Hepática/antagonistas & inibidores , Glicogênio Fosforilase Hepática/química , Glicogênio Fosforilase Hepática/metabolismo , Glicogênio Fosforilase Muscular/antagonistas & inibidores , Glicogênio Fosforilase Muscular/química , Glicogênio Fosforilase Muscular/metabolismo , Humanos , Técnicas In Vitro , Chumbo/química , Chumbo/farmacologia , Modelos Químicos , Estrutura Molecular , Compostos Organometálicos/química , Compostos Organometálicos/farmacologia , Proteínas Recombinantes/antagonistas & inibidores , Proteínas Recombinantes/química , Proteínas Recombinantes/metabolismo , TermodinâmicaRESUMO
The synthesis of a series of novel dihdyropyridine diacid glycogen phosphorylase inhibitors is presented. SAR and functional assay data are discussed, along with the effect of a single inhibitor on blood glucose in a diabetic animal model.
Assuntos
Glicemia/análise , Di-Hidropiridinas/química , Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Hipoglicemiantes/farmacologia , Animais , Diabetes Mellitus Experimental/tratamento farmacológico , Modelos Animais de Doenças , Inibidores Enzimáticos/química , Inibidores Enzimáticos/uso terapêutico , Hipoglicemiantes/química , Hipoglicemiantes/uso terapêutico , CamundongosRESUMO
The preparation of a series of substituted indoles coupled to six- and seven-membered cyclic lactams is described and their role as human glycogen phosphorylase a inhibitors discussed. The SAR of the indole moiety and lactam ring are presented.
Assuntos
Inibidores Enzimáticos/farmacologia , Glicogênio Fosforilase/antagonistas & inibidores , Quinolinas/síntese química , Quinolinas/farmacologia , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/química , Humanos , Cinética , Modelos Moleculares , Conformação Molecular , Quinolinas/química , Relação Estrutura-AtividadeRESUMO
A new class of diacid analogues that binds at the AMP site not only are very potent but have approximately 10-fold selectivity in liver versus muscle glycogen phosphorylase (GP) in the in vitro assay. The synthesis, structure, and in vitro and in vivo biological evaluation of these liver selective glycogen phosphorylase inhibitors are discussed.