RESUMO
Glucagon and insulin have opposing action in governing glucose homeostasis. In type 2 diabetes mellitus (T2DM), plasma glucagon is characteristically elevated, contributing to increased gluconeogenesis and hyperglycemia. Therefore, glucagon receptor (GCGR) antagonism has been proposed as a pharmacologic approach to treat T2DM. In support of this concept, a potent small-molecule GCGR antagonist (GRA), MK-0893, demonstrated dose-dependent efficacy to reduce hyperglycemia, with an HbA1c reduction of 1.5% at the 80 mg dose for 12 weeks in T2DM. However, GRA treatment was associated with dose-dependent elevation of plasma LDL-cholesterol (LDL-c). The current studies investigated the cause for increased LDL-c. We report findings that link MK-0893 with increased glucagon-like peptide 2 and cholesterol absorption. There was not, however, a GRA-related modulation of cholesterol synthesis. These findings were replicated using structurally diverse GRAs. To examine potential pharmacologic mitigation, coadministration of ezetimibe (a potent inhibitor of cholesterol absorption) in mice abrogated the GRA-associated increase of LDL-c. Although the molecular mechanism is unknown, our results provide a novel finding by which glucagon and, hence, GCGR antagonism govern cholesterol metabolism.
Assuntos
Colesterol/sangue , Pirazóis/farmacologia , Receptores de Glucagon/antagonistas & inibidores , beta-Alanina/análogos & derivados , Animais , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/tratamento farmacológico , Avaliação Pré-Clínica de Medicamentos , Humanos , Hipercolesterolemia/induzido quimicamente , Concentração Inibidora 50 , Absorção Intestinal , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Pirazóis/efeitos adversos , beta-Alanina/efeitos adversos , beta-Alanina/farmacologiaRESUMO
Carbapenem-resistant Acinetobacter baumannii infections have limited treatment options. Synthesis, transport and placement of lipopolysaccharide or lipooligosaccharide (LOS) in the outer membrane of Gram-negative bacteria are important for bacterial virulence and survival. Here we describe the cerastecins, inhibitors of the A. baumannii transporter MsbA, an LOS flippase. These molecules are potent and bactericidal against A. baumannii, including clinical carbapenem-resistant Acinetobacter baumannii isolates. Using cryo-electron microscopy and biochemical analysis, we show that the cerastecins adopt a serpentine configuration in the central vault of the MsbA dimer, stalling the enzyme and uncoupling ATP hydrolysis from substrate flipping. A derivative with optimized potency and pharmacokinetic properties showed efficacy in murine models of bloodstream or pulmonary A. baumannii infection. While resistance development is inevitable, targeting a clinically unexploited mechanism avoids existing antibiotic resistance mechanisms. Although clinical validation of LOS transport remains undetermined, the cerastecins may open a path to narrow-spectrum treatment modalities for important nosocomial infections.
Assuntos
Infecções por Acinetobacter , Acinetobacter baumannii , Antibacterianos , Proteínas de Bactérias , Lipopolissacarídeos , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/metabolismo , Lipopolissacarídeos/metabolismo , Animais , Infecções por Acinetobacter/microbiologia , Infecções por Acinetobacter/tratamento farmacológico , Camundongos , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Transporte Biológico , Testes de Sensibilidade Microbiana , Humanos , Microscopia Crioeletrônica , Carbapenêmicos/farmacologia , Carbapenêmicos/metabolismo , Modelos Animais de Doenças , Feminino , Transportadores de Cassetes de Ligação de ATPRESUMO
The synthesis, SAR and binding affinities of cannabinoid-1 receptor (CB1R) inverse agonists based on furo[2,3-b]pyridine scaffolds are described. Food intake, mechanism specific efficacy, pharmacokinetic, and metabolic evaluation of several of these compounds indicate that they are effective orally active modulators of CB1R.
Assuntos
Desenho de Fármacos , Furanos/síntese química , Piridinas/síntese química , Receptor CB1 de Canabinoide/agonistas , Animais , Benzopiranos , Cães , Furanos/química , Furanos/farmacologia , Haplorrinos , Humanos , Concentração Inibidora 50 , Camundongos , Camundongos Knockout , Estrutura Molecular , Piridinas/química , Piridinas/farmacologia , Ratos , Receptor CB1 de Canabinoide/genética , Relação Estrutura-AtividadeRESUMO
Synthesis and structure-activity relationships of cannabinoid-1 receptor (CB1R) inverse agonists based on dihydro-pyrano[2,3-b] pyridine and tetrahydro-1,8-naphtyridine scaffolds are presented. Rat food intake and pharmacokinetic evaluation of 13g, 13i, 13k and 17a revealed these compounds to be highly efficacious orally active modulators of CB1R.
Assuntos
Naftiridinas/química , Piridinas/química , Receptor CB1 de Canabinoide/agonistas , Redução de Peso/efeitos dos fármacos , Administração Oral , Animais , Ingestão de Alimentos , Humanos , Naftiridinas/síntese química , Naftiridinas/farmacologia , Farmacocinética , Piridinas/síntese química , Piridinas/farmacologia , Ratos , Receptor CB1 de Canabinoide/efeitos dos fármacos , Receptor CB2 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Our hollow-fiber infection model simulated the projected steady-state pharmacokinetics of ceftolozane and tazobactam in lung epithelial lining fluid of patients with pneumonia receiving 3 g of ceftolozane/tazobactam every 8 hours. Results confirmed the previously established in vitro activity of ceftolozane/tazobactam at and above approved breakpoints against multidrug-resistant Pseudomonas aeruginosa, regardless of Pseudomonas-derived cephalosporinase allele.
RESUMO
The synthesis, SAR and binding affinities are described for cannabinoid-1 receptor (CB1R) specific inverse agonists based on pyridopyrimidine and heterotricyclic scaffolds. Food intake and pharmacokinetic evaluation of several of these compounds indicate that they are effective orally active modulators of CB1R.
Assuntos
Agonistas de Receptores de Canabinoides , Obesidade/tratamento farmacológico , Pirimidinas/química , Administração Oral , Animais , Canabinoides/química , Química Farmacêutica/métodos , Desenho de Fármacos , Humanos , Concentração Inibidora 50 , Estrutura Terciária de Proteína , Ratos , Receptor CB1 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/agonistas , Relação Estrutura-AtividadeRESUMO
X-ray crystallographic, NMR spectroscopic, and computational studies of taranabant afforded similar low-energy conformers with a significant degree of rigidity along the C11-N13-C14-C16-C17 backbone but with more flexibility around bonds C8-C11 and C8-O7. Mutagenesis and docking studies suggested that taranabant and rimonabant shared the same general binding area of CB1R but with significant differences in detailed interactions. Similar to rimonabant, taranabant interacted with a cluster of aromatic residues (F(3.36)200, W(5.43)279, W(6.48)356, and Y(5.39)275) through the two phenyl rings and with F(2.57)170 and L(7.42)387 through the CF 3-Pyr ring. The notable distinction between taranabant and rimonabant was that taranabant was hydrogen-bonded with S(7.39)383 but not with K(3.28)192, while rimonabant was hydrogen-bonded with K(3.28)192 but not with S(7.39)383. The strong hydrogen bonding between the amide NH of taranabant and hydroxyl of S(7.39)383 was key to the superior affinity of taranabant to CB1R.
Assuntos
Amidas/química , Amidas/farmacologia , Piridinas/química , Piridinas/farmacologia , Receptor CB1 de Canabinoide/agonistas , Sequência de Aminoácidos , Animais , Sítios de Ligação , Células CHO , Células Cultivadas , Simulação por Computador , Cricetinae , Cricetulus , Cristalografia por Raios X , Humanos , Ligação de Hidrogênio , Espectroscopia de Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética/normas , Modelos Moleculares , Conformação Molecular , Dados de Sequência Molecular , Estrutura Molecular , Mutagênese Sítio-Dirigida , Receptor CB1 de Canabinoide/química , Receptor CB1 de Canabinoide/genética , Padrões de Referência , Alinhamento de Sequência , Relação Estrutura-AtividadeRESUMO
The discovery of novel acyclic amide cannabinoid-1 receptor inverse agonists is described. They are potent, selective, orally bioavailable, and active in rodent models of food intake and body weight reduction. A major focus of the optimization process was to increase in vivo efficacy and to reduce the potential for formation of reactive metabolites. These efforts led to the identification of compound 48 for development as a clinical candidate for the treatment of obesity.
Assuntos
Fármacos Antiobesidade/farmacologia , Canabinoides/farmacologia , Obesidade/tratamento farmacológico , Receptor CB1 de Canabinoide/agonistas , Receptor CB2 de Canabinoide/agonistas , Animais , Fármacos Antiobesidade/síntese química , Fármacos Antiobesidade/química , Peso Corporal/efeitos dos fármacos , Canabinoides/síntese química , Canabinoides/química , AMP Cíclico/metabolismo , Ingestão de Alimentos/efeitos dos fármacos , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Microssomos/efeitos dos fármacos , Microssomos/metabolismo , Ratos , Receptor CB1 de Canabinoide/antagonistas & inibidores , Receptor CB1 de Canabinoide/metabolismo , Receptor CB2 de Canabinoide/antagonistas & inibidores , Receptor CB2 de Canabinoide/metabolismoRESUMO
To investigate how specific amino acid residues affect human cannabinoid CB1 receptor binding and activation, CHO cell lines stably expressing wild type and the phenylalanine 200 to alanine mutant of human cannabinoid CB1 receptor (F200A) were examined. AM2233 functions as an agonist at the wild type receptor (EC50=0.93 nM), but behaves as an inverse agonist at F200A (EC50=4.8 nM). The F200A mutant has significantly lower forskolin-stimulated basal cAMP accumulation than that of the wild type, indicating that the F200A mutant possesses higher constitutive activity. F200 doesn't contribute substantially to the high affinity binding of AM2233 at human cannabinoid CB1 receptor. CP55940, HU-210 and Win55212-2 still function as agonists at the F200A mutant, with similar efficacy, potency, and apparent binding affinity for both wild type human cannabinoid CB1 receptor and F200A mutant. These data indicate that the phenylalanine 200 residue in human cannabinoid CB1 receptor is involved in the receptor activation induced by a specific class of agonists, and supports a model of agonist-structure-dependent conformational changes.
Assuntos
Substituição de Aminoácidos , Indóis/farmacologia , Piperidinas/farmacologia , Receptor CB1 de Canabinoide/agonistas , Alanina/genética , Animais , Sítios de Ligação/genética , Ligação Competitiva/genética , Células CHO , Colforsina/farmacologia , Cricetinae , Cricetulus , AMP Cíclico/metabolismo , Cicloexanóis/química , Cicloexanóis/metabolismo , Cicloexanóis/farmacologia , Relação Dose-Resposta a Droga , Expressão Gênica , Humanos , Indóis/química , Indóis/metabolismo , Estrutura Molecular , Toxina Pertussis/farmacologia , Fenilalanina/genética , Piperidinas/química , Piperidinas/metabolismo , Pirazóis/química , Pirazóis/metabolismo , Pirazóis/farmacologia , Receptor CB1 de Canabinoide/genética , Receptor CB1 de Canabinoide/metabolismo , TrítioRESUMO
This paper describes the discovery of N-[(4R)-6-(4-chlorophenyl)-7-(2,4-dichlorophenyl)-2,2-dimethyl-3,4-dihydro-2H-pyrano[2,3-b]pyridin-4-yl]-5-methyl-1H-pyrazole-3-carboxamide (MK-5596, 12c) as a novel cannabinoid-1 receptor (CB1R) inverse agonist for the treatment of obesity. Structure-activity relationship (SAR) studies of lead compound 3, which had off-target hERG (human ether-a-go-go related gene) inhibition activity, led to the identification of several compounds that not only had attenuated hERG inhibition activity but also were subject to glucuronidation in vitro providing the potential for multiple metabolic clearance pathways. Among them, pyrazole 12c was found to be a highly selective CB1R inverse agonist that reduced body weight and food intake in a DIO (diet-induced obese) rat model through a CB1R-mediated mechanism. Although 12c was a substrate of P-glycoprotein (P-gp) transporter, its high in vivo efficacy in rodents, good pharmacokinetic properties in preclinical species, good safety margins, and its potential for a balanced metabolism profile in man allowed for the further evaluation of this compound in the clinic.
Assuntos
Fármacos Antiobesidade/síntese química , Piranos/síntese química , Piridinas/síntese química , Receptor CB1 de Canabinoide/antagonistas & inibidores , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Animais , Fármacos Antiobesidade/farmacocinética , Fármacos Antiobesidade/farmacologia , Ligação Competitiva , Peso Corporal/efeitos dos fármacos , Linhagem Celular , Cricetinae , Cricetulus , Cristalografia por Raios X , Cães , Agonismo Inverso de Drogas , Ingestão de Alimentos/efeitos dos fármacos , Canais de Potássio Éter-A-Go-Go/antagonistas & inibidores , Glucuronídeos/metabolismo , Haplorrinos , Hepatócitos/metabolismo , Humanos , Camundongos , Camundongos Knockout , Modelos Moleculares , Conformação Molecular , Piranos/farmacocinética , Piranos/farmacologia , Piridinas/farmacocinética , Piridinas/farmacologia , Ratos , Receptor CB1 de Canabinoide/genética , Estereoisomerismo , Relação Estrutura-AtividadeRESUMO
Through alternative splicing, the human cannabinoid CB(1) receptor gene encodes three variants of protein products (hCB(1), hCB(1a), and hCB(1b)) that differ in amino acid sequence at the N terminus of the receptors. By semi-quantitative PCR from human adult and fetal brain mRNA, we demonstrated that the transcript encoding hCB(1) is the major transcript, and estimated that those of hCB(1a) and hCB(1b) represent fewer than 5% of the total human cannabinoid CB(1) receptor transcripts. We characterized the three variants stably expressed in CHO cells. In the contrary to the study by Ryberg et al. (FEBS Lett 579[1], 259-64), we did not find substantial difference among the three variants according to the binding affinity, functional potency, and efficacy of meth-anandamide, 2-arachidonoyl glycerol, virodhamine, Noladin ether, docosatetraenylethanolamide, CP55940, AM251, and compound 35e (an acyclic class human CB(1) receptor inverse agonist similar to MK-0364). The functional significance of different human cannabinoid CB(1) receptor variants remains to be clarified.
Assuntos
Encéfalo/metabolismo , Receptor CB1 de Canabinoide/metabolismo , Processamento Alternativo , Animais , Células CHO , Cricetinae , Cricetulus , Humanos , Técnicas In Vitro , Reação em Cadeia da Polimerase , RNA Mensageiro/análise , Receptor CB1 de Canabinoide/genéticaRESUMO
Optimization of the biological activity for 5,6-diarylpyridines as CB1 receptor inverse agonists is described. Food intake and pharmacokinetic evaluation of 3f and 15c indicate that these compounds are effective orally active modulators of CB1.
Assuntos
Química Farmacêutica/métodos , Piridinas/química , Piridinas/síntese química , Receptor CB1 de Canabinoide/agonistas , Animais , Comportamento Animal/efeitos dos fármacos , Desenho de Fármacos , Comportamento Alimentar/efeitos dos fármacos , Concentração Inibidora 50 , Modelos Químicos , Conformação Molecular , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Temperatura , Tolueno/químicaRESUMO
Synthesis, SAR, and binding affinities are described for a new class of 1,8-naphthyridinone CB1 receptor specific inverse agonists. Food intake, knockout mouse, and pharmacokinetic evaluation of 14 indicate that this compound is an effective orally active modulator of CB1.