RESUMO
Direct inhibition of smooth muscle myosin (SMM) is a potential means to treat hypercontractile smooth muscle diseases. The selective inhibitor CK-2018571 prevents strong binding to actin and promotes muscle relaxation in vitro and in vivo. The crystal structure of the SMM/drug complex reveals that CK-2018571 binds to a novel allosteric pocket that opens up during the "recovery stroke" transition necessary to reprime the motor. Trapped in an intermediate of this fast transition, SMM is inhibited with high selectivity compared with skeletal muscle myosin (IC50 = 9 nM and 11,300 nM, respectively), although all of the binding site residues are identical in these motors. This structure provides a starting point from which to design highly specific myosin modulators to treat several human diseases. It further illustrates the potential of targeting transition intermediates of molecular machines to develop exquisitely selective pharmacological agents.
Assuntos
Bibliotecas de Moléculas Pequenas/farmacologia , Miosinas de Músculo Liso/antagonistas & inibidores , Miosinas de Músculo Liso/química , Actinas/metabolismo , Sítio Alostérico , Animais , Cristalografia por Raios X , Cães , Avaliação Pré-Clínica de Medicamentos , Humanos , Modelos Moleculares , Relaxamento Muscular , Músculo Liso/efeitos dos fármacos , Músculo Liso/fisiologia , Ligação Proteica/efeitos dos fármacos , RatosRESUMO
A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKß. In this Letter we document our efforts at further optimization of this series, culminating in 2 with submicromolar potency in a HWB assay and efficacy in a CIA mouse model.
Assuntos
Quinase I-kappa B/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Quinolinas/química , Semicarbazidas/química , Tioureia/análogos & derivados , Animais , Cães , Feminino , Hepatócitos/metabolismo , Ensaios de Triagem em Larga Escala , Humanos , Quinase I-kappa B/metabolismo , Macaca mulatta , Masculino , Camundongos , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Quinolinas/síntese química , Quinolinas/farmacocinética , Ratos , Semicarbazidas/síntese química , Semicarbazidas/farmacocinética , Relação Estrutura-Atividade , Tioureia/síntese química , Tioureia/química , Tioureia/farmacocinéticaRESUMO
A novel series of (E)-1-((2-(1-methyl-1H-imidazol-5-yl) quinolin-4-yl) methylene) thiosemicarbazides was discovered as potent inhibitors of IKKß. In this Letter we document our early efforts at optimization of the quinoline core, the imidazole and the semithiocarbazone moiety. Most potency gains came from substitution around the 6- and 7-positions of the quinoline ring. Replacement of the semithiocarbazone with a semicarbazone decreased potency but led to some measurable exposure.
Assuntos
Quinase I-kappa B/antagonistas & inibidores , Inibidores de Proteínas Quinases/química , Semicarbazidas/química , Animais , Cães , Feminino , Ensaios de Triagem em Larga Escala , Quinase I-kappa B/metabolismo , Masculino , Microssomos/metabolismo , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacocinética , Quinolinas/química , Ratos , Semicarbazidas/síntese química , Semicarbazidas/farmacocinética , Relação Estrutura-AtividadeRESUMO
The discovery of reldesemtiv, a second-generation fast skeletal muscle troponin activator (FSTA) that increases force production at submaximal stimulation frequencies, is reported. Property-based optimization of high throughput screening hit 1 led to compounds with improved free exposure and in vivo muscle activation potency compared to the first-generation FSTA, tirasemtiv. Reldesemtiv demonstrated increased muscle force generation in a phase 1 clinical trial and is currently being evaluated in clinical trials for the treatment of amyotrophic lateral sclerosis.
Assuntos
Descoberta de Drogas , Músculo Esquelético/efeitos dos fármacos , Troponina/metabolismo , Relação Dose-Resposta a Droga , Humanos , Estrutura Molecular , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Relação Estrutura-AtividadeRESUMO
The identification and optimization of the first activators of fast skeletal muscle are reported. Compound 1 was identified from high-throughput screening (HTS) and subsequently found to improve muscle function via interaction with the troponin complex. Optimization of 1 for potency, metabolic stability, and physical properties led to the discovery of tirasemtiv (25), which has been extensively characterized in clinical trials for the treatment of amyotrophic lateral sclerosis.
RESUMO
Limited neural input results in muscle weakness in neuromuscular disease because of a reduction in the density of muscle innervation, the rate of neuromuscular junction activation or the efficiency of synaptic transmission. We developed a small-molecule fast-skeletal-troponin activator, CK-2017357, as a means to increase muscle strength by amplifying the response of muscle when neural input is otherwise diminished secondary to neuromuscular disease. Binding selectively to the fast-skeletal-troponin complex, CK-2017357 slows the rate of calcium release from troponin C and sensitizes muscle to calcium. As a consequence, the force-calcium relationship of muscle fibers shifts leftwards, as does the force-frequency relationship of a nerve-muscle pair, so that CK-2017357 increases the production of muscle force in situ at sub-maximal nerve stimulation rates. Notably, we show that sensitization of the fast-skeletal-troponin complex to calcium improves muscle force and grip strength immediately after administration of single doses of CK-2017357 in a model of the neuromuscular disease myasthenia gravis. Troponin activation may provide a new therapeutic approach to improve physical activity in diseases where neuromuscular function is compromised.
Assuntos
Cálcio/metabolismo , Músculo Esquelético/metabolismo , Doenças Neuromusculares/metabolismo , Troponina C/agonistas , Troponina C/metabolismo , Adenosina Trifosfatases/metabolismo , Animais , Bovinos , Humanos , Imidazóis/química , Imidazóis/uso terapêutico , Terapia de Alvo Molecular , Contração Muscular/efeitos dos fármacos , Fibras Musculares Esqueléticas/citologia , Fibras Musculares Esqueléticas/metabolismo , Músculo Esquelético/patologia , Miastenia Gravis/tratamento farmacológico , Miastenia Gravis/metabolismo , Miastenia Gravis/patologia , Miosinas/isolamento & purificação , Miosinas/metabolismo , Doenças Neuromusculares/tratamento farmacológico , Doenças Neuromusculares/patologia , Pirazinas/química , Pirazinas/uso terapêutico , Coelhos , Ratos , Troponina/metabolismo , Troponina/fisiologiaRESUMO
Decreased cardiac contractility is a central feature of systolic heart failure. Existing drugs increase cardiac contractility indirectly through signaling cascades but are limited by their mechanism-related adverse effects. To avoid these limitations, we previously developed omecamtiv mecarbil, a small-molecule, direct activator of cardiac myosin. Here, we show that it binds to the myosin catalytic domain and operates by an allosteric mechanism to increase the transition rate of myosin into the strongly actin-bound force-generating state. Paradoxically, it inhibits adenosine 5'-triphosphate turnover in the absence of actin, which suggests that it stabilizes an actin-bound conformation of myosin. In animal models, omecamtiv mecarbil increases cardiac function by increasing the duration of ejection without changing the rates of contraction. Cardiac myosin activation may provide a new therapeutic approach for systolic heart failure.
Assuntos
Miosinas Cardíacas/metabolismo , Insuficiência Cardíaca Sistólica/tratamento farmacológico , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Ureia/análogos & derivados , Citoesqueleto de Actina/metabolismo , Actinas/metabolismo , Adenosina Trifosfatases/metabolismo , Trifosfato de Adenosina/metabolismo , Agonistas Adrenérgicos beta/farmacologia , Regulação Alostérica , Animais , Sítios de Ligação , Cálcio/metabolismo , Miosinas Cardíacas/química , Débito Cardíaco/efeitos dos fármacos , Cães , Feminino , Insuficiência Cardíaca Sistólica/fisiopatologia , Isoproterenol/farmacologia , Masculino , Miócitos Cardíacos/fisiologia , Fosfatos/metabolismo , Ligação Proteica , Conformação Proteica , Isoformas de Proteínas/química , Isoformas de Proteínas/metabolismo , Ratos , Ratos Sprague-Dawley , Ureia/química , Ureia/metabolismo , Ureia/farmacologia , Função Ventricular Esquerda/efeitos dos fármacosRESUMO
We report the design, synthesis, and optimization of the first, selective activators of cardiac myosin. Starting with a poorly soluble, nitro-aromatic hit compound (1), potent, selective, and soluble myosin activators were designed culminating in the discovery of omecamtiv mecarbil (24). Compound 24 is currently in clinical trials for the treatment of systolic heart failure.