RESUMO
The discovery of a novel 2-aminotetrahydropyridine class of BACE1 inhibitors is described. Their pKa and lipophilicity were modulated by a pending sulfonyl group, while good permeability and brain penetration were achieved via intramolecular hydrogen bonding. BACE1 selectivity over BACE2 was achieved in the S3 pocket by a novel bicyclic ring system. An optimization addressing reactive metabolite formation, cardiovascular safety, and CNS toxicity is described, leading to the clinical candidate JNJ-67569762 (12), which gave robust dose-dependent BACE1-mediated amyloid ß lowering without showing BACE2-dependent hair depigmentation in preclinical models. We show that 12 has a favorable projected human dose and PK and hence presented us with an opportunity to test a highly selective BACE1 inhibitor in humans. However, 12 was found to have a QT effect upon repeat dosing in dogs and its development was halted in favor of other selective leads, which will be reported in the future.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Descoberta de Drogas , Pirrolidinas/farmacologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Ácido Aspártico Endopeptidases/metabolismo , Cristalografia por Raios X , Relação Dose-Resposta a Droga , Humanos , Modelos Moleculares , Estrutura Molecular , Pirrolidinas/síntese química , Pirrolidinas/química , Relação Estrutura-AtividadeRESUMO
The blood-brain barrier (BBB) is often a limiting factor for getting drugs in the brain. Bypassing the BBB by intranasal (IN), or also called nose to brain (NTB), route is an interesting and frequently investigated concept for brain drug delivery. However, despite the body of evidence for IN drug delivery in literature over the last decades, reproducibility and interpretation of animal data remain challenging. The objective of this project was to assess the feasibility and value of a standardized IN screening model in rats for the evaluation of direct brain delivery. A chemically diverse set of commercial and internal small molecules were tested in the in vivo model with different doses and/or formulations. Data were analyzed using different ways of ratio calculations: blood concentration at time of sacrifice, total exposure in blood (area under the curve, AUC) and the brain or olfactory bulb concentrations. The IN route was compared to another parenteral route to decide if there is potential direct brain transport. The results show that blood and tissue concentrations and ratios are highly variable and not always reproducible. Potential direct brain delivery was concluded for some compounds, however, sometimes depending on the analysis: using blood levels at sacrifice or AUC could lead to different conclusions. We conclude that a screening model for the evaluation of direct brain transport of small molecules is very difficult to achieve and a conclusion based on a limited number of animals with this variability is questionable.
Assuntos
Mucosa Nasal/metabolismo , Bulbo Olfatório/efeitos dos fármacos , Bibliotecas de Moléculas Pequenas/administração & dosagem , Administração Intranasal , Animais , Transporte Biológico/fisiologia , Barreira Hematoencefálica/metabolismo , Química Farmacêutica/métodos , Sistemas de Liberação de Medicamentos/métodos , Masculino , Ratos , Ratos Sprague-Dawley , Reprodutibilidade dos TestesRESUMO
INTRODUCTION: Clinical observations are routinely used to address drug-induced behavioural changes in dogs. To deal with the limitations of this methodology, we evaluated Actiwatch-Mini® as a tool to monitor continuously locomotor activity in dogs and to provide objective parameters that could be linked to behavioural changes after compound administration. METHODS: Eight Beagles were equipped with Actiwatch-Mini®. As a reference drug, a PDE2-inhibitor was administered daily for six days at doses known to cause minor or severe behavioural changes. RESULTS: While traditional observation showed no behavioural changes - except sedation - dogs receiving 0.5 mg/kg/day, showed significant increases in % immobile time (+15.8%) and mean length of immobile phases (+1.2 min) but no change in number of immobile phases (+2.2). At 1 mg/kg/day, light to severe changes in behaviour were present. Actiwatch-Mini® recorded an increase in mean length of immobile phases (+1.9 min) and a decrease in mean number of immobile phases (-7.4) in the first four hours after each dosing while total % immobile time was not significantly increased (+4.9%). DISCUSSION: Actiwatch-Mini® was able to detect changes in immobility parameters in dogs dosed with a PDE2-inhibitor while no or only minor behavioural changes were observed. The system can be used for continuously monitoring the activity of dogs, to provide objective scores for evaluation of activity. It provides an inexpensive and low labour-intensive method for detecting changes in activity and possible early indications of drug-induced behavioural changes.
Assuntos
Comportamento Animal/efeitos dos fármacos , Monitorização Fisiológica/métodos , Atividade Motora/efeitos dos fármacos , Inibidores de Fosfodiesterase/toxicidade , Animais , Nucleotídeo Cíclico Fosfodiesterase do Tipo 2/antagonistas & inibidores , Cães , Feminino , Masculino , Monitorização Fisiológica/instrumentação , Inibidores de Fosfodiesterase/administração & dosagem , Fatores de TempoRESUMO
The ß-site amyloid precursor protein cleaving enzyme 1 (BACE1, also known as ß-secretase) is a promising target for the treatment of Alzheimer's disease. A pKa lowering approach over the initial leads was adopted to mitigate hERG inhibition and P-gp efflux, leading to the design of 6-CF3 dihydrothiazine 8 (N-(3-((4S,6S)-2-amino-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-thiazin-4-yl)-4-fluorophenyl)-5-cyanopicolinamide). Optimization of 8 led to the discovery of 15 (N-(3-((4S,6S)-2-amino-4-methyl-6-(trifluoromethyl)-5,6-dihydro-4H-1,3-thiazin-4-yl)-4-fluorophenyl)-5-(fluoromethoxy)pyrazine-2-carboxamide) with an excellent balance of potency, hERG inhibition, P-gp efflux, and metabolic stability. Oral administration of 8 elicited robust Aß reduction in dog even at 0.16â mg/kg. Reflecting the reduced hERG inhibitory activity, no QTc prolongation was observed at high doses. The potential for reactive metabolite formation of 15 was realized in a nucleophile trapping assay using [14 C]-KCN in human liver microsomes. Utilizing covalent binding (CVB) in human hepatocytes and the maximum projected human dosage, the daily CVB burden of 15 was calculated to be at an acceptable value of below 1â mg/day. However, hepatotoxicity was observed when 15 was subjected to a two-week tolerance study in dog, which prevented further evaluation of this compound.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Oxazinas/farmacologia , Tiazinas/farmacologia , Secretases da Proteína Precursora do Amiloide/deficiência , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Ácido Aspártico Endopeptidases/deficiência , Ácido Aspártico Endopeptidases/metabolismo , Cães , Relação Dose-Resposta a Droga , Desenho de Fármacos , Hepatócitos/efeitos dos fármacos , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos ICR , Camundongos Knockout , Microssomos Hepáticos/química , Microssomos Hepáticos/metabolismo , Modelos Moleculares , Estrutura Molecular , Oxazinas/química , Ratos , Relação Estrutura-Atividade , Tiazinas/administração & dosagem , Tiazinas/químicaRESUMO
Genetic evidence points to deposition of amyloid-ß (Aß) as a causal factor for Alzheimer's disease. Aß generation is initiated when ß-secretase (BACE1) cleaves the amyloid precursor protein. Starting with an oxazine lead 1, we describe the discovery of a thiazine-based BACE1 inhibitor 5 with robust Aß reduction in vivo at low concentrations, leading to a low projected human dose of 14 mg/day where 5 achieved sustained Aß reduction of 80% at trough level.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Inibidores de Proteases/química , Tiazinas/química , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Citocromo P-450 CYP2C9/química , Citocromo P-450 CYP2C9/metabolismo , Cães , Avaliação Pré-Clínica de Medicamentos , Feminino , Meia-Vida , Haplorrinos , Coração/efeitos dos fármacos , Humanos , Fígado/efeitos dos fármacos , Fígado/metabolismo , Masculino , Camundongos , Inibidores de Proteases/farmacocinética , Inibidores de Proteases/farmacologia , Ratos , Ratos Sprague-Dawley , Tiazinas/metabolismo , Tiazinas/farmacologiaRESUMO
The discovery, design and synthesis of a new series of GSMs is described. The classical imidazole heterocycle has been replaced by a cyano group attached to an indole nucleus. The exploration of this series has led to compound 26-S which combined high in vitro and in vivo potency with an acceptable drug-like profile.
Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Indóis/síntese química , Desenho de Fármacos , Humanos , Relação Estrutura-AtividadeRESUMO
ß-Secretase (BACE1) has an essential role in the production of amyloid ß peptides that accumulate in patients with Alzheimer's disease (AD). Thus, inhibition of BACE1 is considered to be a disease-modifying approach for the treatment of AD. Our hit-to-lead efforts led to a cellular potent 1,3-dihydro-oxazine 6, which however inhibited hERG and showed high P-gp efflux. The close analogue of 5-fluoro-oxazine 8 reduced P-gp efflux; further introduction of electron withdrawing groups at the 6-position improved potency and also mitigated P-gp efflux and hERG inhibition. Changing to a pyrazine followed by optimization of substituents on both the oxazine and the pyrazine culminated in 24 with robust Aß reduction in vivo at low doses as well as reduced CYP2D6 inhibition. On the basis of the X-ray analysis and the QM calculation of given dihydro-oxazines, we reasoned that the substituents at the 6-position as well as the 5-fluorine on the oxazine would stabilize a bioactive conformation to increase potency.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Descoberta de Drogas , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Oxazinas/química , Oxazinas/farmacologia , Secretases da Proteína Precursora do Amiloide/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Relação Dose-Resposta a Droga , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacocinética , Humanos , Simulação de Acoplamento Molecular , Oxazinas/metabolismo , Oxazinas/farmacocinética , Conformação Proteica , Ratos , Ratos Sprague-Dawley , Relação Estrutura-Atividade , Distribuição TecidualRESUMO
In previous studies, the introduction of electron withdrawing groups to 1,4-oxazine BACE1 inhibitors reduced the p Ka of the amidine group, resulting in compound 2 that showed excellent in vivo efficacy, lowering Aß levels in brain and CSF. However, a suboptimal cardiovascular safety margin, based on QTc prolongation, prevented further progression. Further optimization resulted in the replacement of the 2-fluoro substituent by a CF3-group, which reduced hERG inhibition. This has led to compound 3, with an improved cardiovascular safety margin and sufficiently safe in GLP toxicity studies to progress into clinical trials.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores de Proteases/química , Inibidores de Proteases/farmacologia , Administração Intravenosa , Administração Oral , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais , Ácido Aspártico Endopeptidases/metabolismo , Disponibilidade Biológica , Doenças Cardiovasculares/induzido quimicamente , Doença Hepática Induzida por Substâncias e Drogas/etiologia , Cães , Avaliação Pré-Clínica de Medicamentos/métodos , Estabilidade de Medicamentos , Canal de Potássio ERG1/metabolismo , Cobaias , Humanos , Masculino , Camundongos Endogâmicos , Oxazinas/química , Fragmentos de Peptídeos/líquido cefalorraquidiano , Inibidores de Proteases/administração & dosagem , Inibidores de Proteases/efeitos adversos , Ratos Sprague-Dawley , Relação Estrutura-AtividadeRESUMO
Accumulation of Aß peptides is a hallmark of Alzheimer's disease (AD) and is considered a causal factor in the pathogenesis of AD. ß-Secretase (BACE1) is a key enzyme responsible for producing Aß peptides, and thus agents that inhibit BACE1 should be beneficial for disease-modifying treatment of AD. Here we describe the discovery and optimization of novel oxazine-based BACE1 inhibitors by lowering amidine basicity with the incorporation of a double bond to improve brain penetration. Starting from a 1,3-dihydrooxazine lead 6 identified by a hit-to-lead SAR following HTS, we adopted a p Ka lowering strategy to reduce the P-gp efflux and the high hERG potential leading to the discovery of 15 that produced significant Aß reduction with long duration in pharmacodynamic models and exhibited wide safety margins in cardiovascular safety models. This compound improved the brain-to-plasma ratio relative to 6 by reducing P-gp recognition, which was demonstrated by a P-gp knockout mouse model.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/metabolismo , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Oxazinas/química , Fragmentos de Peptídeos/metabolismo , Inibidores de Proteases/química , Inibidores de Proteases/farmacologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Secretases da Proteína Precursora do Amiloide/química , Animais , Ácido Aspártico Endopeptidases/química , Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Cristalografia por Raios X , Cães , Desenho de Fármacos , Canal de Potássio ERG1/metabolismo , Cobaias , Humanos , Células Madin Darby de Rim Canino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Oxazinas/farmacologia , Inibidores de Proteases/farmacocinética , Relação Estrutura-AtividadeRESUMO
Pyrrolo[3,2-d]pyrimidines were identified as a new series of potent and selective TLR7 agonists. Compounds were optimized for their activity and selectivity over TLR8. This presents an advantage over recently described scaffolds that have residual TLR8 activity, which may be detrimental to the tolerability of the candidate drug. Oral administration of the lead compound 54 effectively induced a transient interferon stimulated gene (ISG) response in mice and cynomolgus monkeys. We aimed for a high first pass effect, limiting cytokine induction systemically, and demonstrated the potential for the immunotherapy of viral hepatitis.
Assuntos
Antivirais/síntese química , Hepatite B/tratamento farmacológico , Pirimidinas/síntese química , Pirróis/síntese química , Receptor 7 Toll-Like/agonistas , Administração Oral , Animais , Antivirais/farmacocinética , Antivirais/farmacologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Cães , Feminino , Genes Reporter , Células HEK293 , Hepatite B/imunologia , Humanos , Imunoterapia , Interferons/biossíntese , Macaca fascicularis , Células Madin Darby de Rim Canino , Camundongos Endogâmicos C57BL , Simulação de Acoplamento Molecular , Pirimidinas/farmacocinética , Pirimidinas/farmacologia , Pirróis/farmacocinética , Pirróis/farmacologia , Ratos , Relação Estrutura-Atividade , Receptor 7 Toll-Like/genética , Receptor 8 Toll-Like/agonistas , Receptor 8 Toll-Like/genéticaRESUMO
Understanding differences in Alzheimer's disease biomarkers before the pathology becomes evident can contribute to an improved understanding of disease pathogenesis and treatment. A decrease in amyloid-ß (Aß)42 in cerebrospinal fluid (CSF) is suggested to be a biomarker for Aß deposition in brain. However, the relevance of CSF Aß levels prior to deposition is not entirely known. Dogs are similar to man with respect to amyloid-ß protein precursor (AßPP)-processing, age-related amyloid plaque deposition, and cognitive dysfunction. In the current study, we evaluated the relation between CSF Aß42 levels and cognitive performance in young to middle-aged dogs (1.5-7 years old). Additionally, CSF sAßPPα and sAßPPß were measured to evaluate AßPP processing, and CSF cytokines were measured to determine the immune status of the brain. We identified two groups of dogs showing consistently low or high CSF Aß42 levels. Based on prior studies, it was assumed that at this age no cerebral amyloid plaques were likely to be present. The cognitive performance was evaluated in standard cognition tests. Low or high Aß concentrations coincided with low or high sAßPPα, sAßPPß, and CXCL-1 levels, respectively. Dogs with high Aß concentrations showed significant learning impairments on delayed non-match to position (DNMP), object discrimination, and reversal learning compared to dogs with low Aß concentrations. Our data support the hypothesis that high levels of CSF Aß in dogs coincide with lower cognitive performance prior to amyloid deposition. Further experiments are needed to investigate this link, as well as the relevance with respect to Alzheimer's disease pathology progression.
Assuntos
Envelhecimento/líquido cefalorraquidiano , Envelhecimento/psicologia , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Precursor de Proteína beta-Amiloide/líquido cefalorraquidiano , Disfunção Cognitiva/líquido cefalorraquidiano , Doenças do Cão/líquido cefalorraquidiano , Fragmentos de Peptídeos/líquido cefalorraquidiano , Animais , Biomarcadores/líquido cefalorraquidiano , Quimiocina CXCL1/líquido cefalorraquidiano , Comportamento de Escolha , Cognição , Discriminação Psicológica , Cães , Feminino , Masculino , Testes Neuropsicológicos , Reversão de Aprendizagem , RecompensaRESUMO
Toll-like receptor (TLR) 7 and 8 agonists can potentially be used in the treatment of viral infections and are particularly promising for chronic hepatitis B virus (HBV) infection. An internal screening effort identified a pyrimidine Toll-like receptor 7 and 8 dual agonist. This provided a novel alternative over the previously reported adenine and pteridone type of agonists. Structure-activity relationship, lead optimization, in silico docking, pharmacokinetics, and demonstration of ex vivo and in vivo cytokine production of the lead compound are presented.
Assuntos
Antivirais/química , Vírus da Hepatite B/efeitos dos fármacos , Pirimidinas/química , Receptor 7 Toll-Like/agonistas , Receptor 8 Toll-Like/agonistas , Animais , Antivirais/síntese química , Antivirais/farmacocinética , Antivirais/farmacologia , Simulação por Computador , Citocinas/biossíntese , Cães , Hepatite B/tratamento farmacológico , Hepatite B/virologia , Vírus da Hepatite B/fisiologia , Ensaios de Triagem em Larga Escala , Humanos , Macaca fascicularis , Camundongos , Camundongos Endogâmicos C57BL , Simulação de Acoplamento Molecular , Pirimidinas/síntese química , Pirimidinas/farmacocinética , Pirimidinas/farmacologia , Ratos Sprague-Dawley , Estereoisomerismo , Relação Estrutura-Atividade , Replicação Viral/efeitos dos fármacosRESUMO
Nalmefene is an opioid antagonist which as a once-a-day tablet formulation has recently been approved for reducing ethanol intake in alcoholic subjects. In order to address the compliance issue in this patient population, a number of potential nalmefene prodrugs were synthesized with the aim of providing a formulation that could provide plasma drug concentrations in the region of 0.5-1.0ng/mL for a one-month period when dosed intramuscular to dogs or minipigs. In an initial series of studies, three different lipophilic nalmefene derivatives were evaluated: the palmitate (C16), the octadecyl glutarate diester (C18-C5) and the decyl carbamate (CB10). They were administered intramuscularly to dogs in a sesame oil solution at a dose of 1mg-eq. nalmefene/kg. The decyl carbamate was released relatively quickly from the oil depot and its carbamate bond was too stable to be used as a prodrug. The other two derivatives delivered a fairly constant level of 0.2-0.3ng nalmefene/mL plasma for one month and since there was no significant difference between these two, the less complex palmitate monoester was chosen to demonstrate that dog plasma nalmefene concentrations were dose-dependent at 1, 5 and 20mg-eq. nalmefene/kg. In a second set of experiments, the effect of the chain length of the fatty acid monoester promoieties was examined. The increasingly lipophilic octanoate (C8), decanoate (C10) and dodecanoate (C12) derivatives were evaluated in dogs and in minipigs, at a dose of 5mg-eq. nalmefene/kg and plasma nalmefene concentrations were measured over a four-week period. The pharmacokinetic profiles were very similar in both species with Cmax decreasing and Tmax increasing with increasing fatty acid chain length and the target plasma concentrations (0.5-1.0ng/mL over a month-long period) were achieved with the dodecanoate (C12) prodrug. These data therefore demonstrate that sustained plasma nalmefene concentrations can be achieved in both dog and minipig using nalmefene prodrugs and that the pharmacokinetic profile of nalmefene can be tuned by varying the length of the alkyl group.
Assuntos
Carbamatos , Ácidos Graxos , Glutaratos , Naltrexona/análogos & derivados , Antagonistas de Entorpecentes , Pró-Fármacos , Animais , Carbamatos/química , Carbamatos/farmacocinética , Preparações de Ação Retardada/química , Preparações de Ação Retardada/farmacocinética , Cães , Ácidos Graxos/química , Ácidos Graxos/farmacocinética , Feminino , Glutaratos/química , Glutaratos/farmacocinética , Masculino , Naltrexona/sangue , Naltrexona/química , Naltrexona/farmacocinética , Antagonistas de Entorpecentes/sangue , Antagonistas de Entorpecentes/química , Antagonistas de Entorpecentes/farmacocinética , Pró-Fármacos/química , Pró-Fármacos/farmacocinética , Suínos , Porco MiniaturaRESUMO
INTRODUCTION: Alzheimer's disease brains are characterized by extracellular plaques containing the aggregated amyloid ß42 (Aß42) peptide and intraneuronal tangles containing hyperphosphorylated tau. Aß42 is produced by sequential processing of the amyloid precursor protein (APP) by ß-secretase followed by γ-secretase. Substantial efforts have been put into developing pharmaceuticals preventing the production or increasing the clearance of Aß42. However, treatments inhibiting γ-secretase have proven disappointing due to off-target effects. To circumvent these effects, γ-secretase modulators (GSMs) have been developed, which rather than inhibiting γ-secretase shift its preference into producing less aggregation-prone shorter Aß peptides. Belonging to the same family of proteins as APP, amyloid-like protein 1 (APLP1) is also a substrate for γ-secretase. Herein we investigated whether the GSM E2012 affects APLP1 processing in the central nervous system by measuring APLP1 peptide levels in cerebrospinal fluid (CSF) before and after E2012 treatment in dogs. METHODS: An in-house monoclonal APLP1 antibody, AP1, was produced and utilized for immunopurification of APLP1 from human and dog CSF in a hybrid immuno-affinity mass spectrometric method. Seven dogs received a single dose of 20 or 80 mg/kg of E2012 in a randomized cross-over design and CSF was collected prior to and 4, 8 and 24 hours after dosing. RESULTS: We have identified 14 CSF APLP1 peptides in humans and 12 CSF APLP1 peptides in dogs. Of these, seven were reproducibly detectable in dogs who received E2012. We found a dose-dependent relative increase of the CSF peptides APLP1ß17, 1ß18 and 1ß28 accompanied with a decrease of 1ß25 and 1ß27 in response to E2012 treatment. All peptides reverted to baseline over the time of sample collection. CONCLUSION: We show an in vivo effect of the GSM E2012 on the processing of APLP1 which is measurable in CSF. These data suggest that APLP1 peptides may be used as biomarkers to monitor drug effects of GSMs on γ-secretase processing in clinical trials. However, this requires further investigation in larger cohorts, including studies in man.
Assuntos
Secretases da Proteína Precursora do Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/líquido cefalorraquidiano , Imidazóis/farmacologia , Piperidinas/farmacologia , Sequência de Aminoácidos , Precursor de Proteína beta-Amiloide/genética , Precursor de Proteína beta-Amiloide/imunologia , Animais , Anticorpos Monoclonais/isolamento & purificação , Biomarcadores Farmacológicos/líquido cefalorraquidiano , Estudos Cross-Over , Cães , Relação Dose-Resposta a Droga , Feminino , Humanos , Imunoprecipitação , Camundongos Endogâmicos BALB C , Distribuição Aleatória , Espectrometria de Massas em TandemRESUMO
1,4-Oxazines are presented, which show good in vitro inhibition in enzymatic and cellular BACE1 assays. We describe lead optimization focused on reducing the amidine pKa while optimizing interactions in the BACE1 active site. Our strategy permitted modulation of properties such as permeation and especially P-glycoprotein efflux. This led to compounds which were orally bioavailable, centrally active, and which demonstrated robust lowering of brain and CSF Aß levels, respectively, in mouse and dog models. The amyloid lowering potential of these molecules makes them valuable leads in the search for new BACE1 inhibitors for the treatment of Alzheimer's disease.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Encéfalo/metabolismo , Oxazinas/síntese química , Oxazinas/farmacologia , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/antagonistas & inibidores , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Animais , Disponibilidade Biológica , Proteínas Sanguíneas/metabolismo , Barreira Hematoencefálica , Linhagem Celular Tumoral , Inibidores das Enzimas do Citocromo P-450/síntese química , Inibidores das Enzimas do Citocromo P-450/farmacologia , Cães , Desenho de Fármacos , Feminino , Humanos , Masculino , Camundongos , Modelos Moleculares , Oxazinas/farmacocinética , Ligação ProteicaRESUMO
The design and synthesis of a novel series of potent gamma secretase modulators is described. Exploration of various spacer groups between the triazole ring and the aromatic appendix in 2 has led to anilinotriazole 28, which combined high in vitro and in vivo potency with an acceptable drug-like profile.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Compostos de Anilina/química , Triazóis/química , Secretases da Proteína Precursora do Amiloide/metabolismo , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/metabolismo , Compostos de Anilina/síntese química , Compostos de Anilina/metabolismo , Animais , Encéfalo/metabolismo , Desenho de Fármacos , Humanos , Camundongos , Camundongos Transgênicos , Ligação Proteica , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/metabolismoRESUMO
INTRODUCTION: Regarding evaluation of drug-induced changes in left ventricular contractility in safety pharmacology there is still a gap in knowledge between preclinically and clinically used measurements. METHODS: As a step towards translation of preclinical to clinical outcomes, this study in telemetered dogs was initiated to compare indexes of contractility, such as LV dP/dt(max) (contractility measured as the maximum raise of pressure in the left ventricle) and LV dP/dt(max)/P (contractility measured as the maximum raise of pressure in the left ventricle, corrected for pressure) (telemetry; both commonly preclinically used) and EF (ejection fraction) and FS (fractional shortening) (echocardiography; both commonly clinically used). Different inotropic states were induced by minoxidil, milrinone, isoprenaline, clonidine, atenolol and verapamil. RESULTS: Both techniques demonstrated reproducible changes in contractility which showed a clear linear association. A change in LV dP/dt(max) of 1000 mmHg/s (in the range of 2500 to 7500 mmHg/s; in healthy dogs) corresponded with a change in ejection fraction of approximately 7% and a fractional shortening of approximately 6%. A change of 10/s LV dP/dt(max)/P (in the range of 35 to 85/s; in healthy dogs) corresponded with a change in ejection fraction of approximately 7% and a fractional shortening of 7%. DISCUSSION: The correlation found in this study could potentially enable a better--translational--assessment of the clinical relevance of changes in contractility indices measured with telemetry devices in preclinical safety studies.
Assuntos
Cardiotônicos/farmacologia , Coração/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Função Ventricular Esquerda/efeitos dos fármacos , Animais , Cães , Ecocardiografia/métodos , Feminino , Ventrículos do Coração/efeitos dos fármacos , Telemetria/métodos , Pressão Ventricular/efeitos dos fármacosRESUMO
Beta-secretase is the first cleavage enzyme of amyloid-ß protein precursor (AßPP) in the amyloidogenic pathway, leading to the formation of the plaque forming Amyloid-ß (Aß)1-42 peptide. BACE (beta-site AßPP cleaving enzyme) 1 inhibition is therefore considered to be a promising disease modifying therapy for Alzheimer's disease. An early assessment of the in vivo activity of BACE inhibitors was done in dogs since AßPP processing is the same as in humans and this species easily enables longitudinal cerebrospinal fluid (CSF) sampling. Aß changes in CSF compared to baseline are used to evaluate target engagement of the compounds. Levels of Aß1-37, Aß1-38, Aß1-40, and Aß1-42 in CSF are measured with immunoassay (Mesoscale electrochemiluminescence technology) and with an ultra high-performance liquid chromatography mass spectrometry (UPLC-MS/MS). Two experimental BACE inhibitors were evaluated. With the immunoassay, a dose dependent decrease is observed for all four Aß peptides. Measurements with the UPLC-MS/MS are in line with the immunoassay for Aß1-37, Aß1-38, and Aß1-40, however, for Aß1-42, differences are sometimes observed when comparing to changes seen in the other peptides with UPLC-MS/MS and with immunoassay results. Generally lower concentrations are measured with immunoassay. The reason for these differences is still unknown. Aß1-42 is more prone to form aggregates compared to the other peptides. One hypothesis could be that while the immunoassay only measures free Aß, bound and aggregated Aß peptides are at least partially dissolved with the UPLC-MS/MS method, since acetonitrile is added to the CSF samples. This increases variability in the concentration of Aß peptide measured with UPLC-MS/MS, especially for Aß1-42, potentially masking the compound effect on Aß1-42 levels.
Assuntos
Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Peptídeos beta-Amiloides/líquido cefalorraquidiano , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Fragmentos de Peptídeos/líquido cefalorraquidiano , Animais , Cromatografia Líquida de Alta Pressão , Cisterna Magna/metabolismo , Cães , Relação Dose-Resposta a Droga , Feminino , Imunoensaio , Imunoprecipitação , Ventrículos Laterais/metabolismo , Masculino , Modelos Animais , Espectrometria de Massas em TandemRESUMO
The design and the synthesis of several chemical subclasses of imidazole containing γ-secretase modulators (GSMs) is described. Conformational restriction of pyridone 4 into bicyclic pyridone isosteres has led to compounds with high in vitro and in vivo potency. This has resulted in the identification of benzimidazole 44a as a GSM with low nanomolar potency in vitro. In mouse, rat, and dog, this compound displayed the typical γ-secretase modulatory profile by lowering Aß42 and Aß40 levels combined with an especially pronounced increase in Aß38 and Aß37 levels while leaving the total levels of amyloid peptides unchanged.