RESUMEN
γ-Secretase is a large enzyme complex comprising presenilin, nicastrin, presenilin enhancer 2, and anterior pharynx-defective 1 that mediates the intramembrane proteolysis of a large number of proteins including amyloid precursor protein and Notch. Recently, a novel γ-secretase activating protein (GSAP) was identified that interacts with γ-secretase and the C-terminal fragment of amyloid precursor protein to selectively increase amyloid-ß production. In this study we have further characterized the role of endogenous and exogenous GSAP in the regulation of γ-secretase activity and amyloid-ß production in vitro. Knockdown of GSAP expression in N2a cells decreased amyloid-ß levels. In contrast, overexpression of GSAP in HEK cells expressing amyloid precursor protein or in N2a cells had no overt effect on amyloid-ß generation. Likewise, purified recombinant GSAP had no effect on amyloid-ß generation in two distinct in vitro γ-secretase assays. In subsequent cellular studies with imatinib, a kinase inhibitor that reportedly prevents the interaction of GSAP with the C-terminal fragment of amyloid precursor protein, a concentration-dependent decrease in amyloid-ß levels was observed. However, no interaction between GSAP and the C-terminal fragment of amyloid precursor protein was evident in co-immunoprecipitation studies. In addition, subchronic administration of imatinib to rats had no effect on brain amyloid-ß levels. In summary, these findings suggest the roles of GSAP and imatinib in the regulation of γ-secretase activity and amyloid-ß generation are uncertain.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Péptidos beta-Amiloides/metabolismo , Regulación de la Expresión Génica , Piperazinas/farmacología , Proteínas/química , Pirimidinas/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Enfermedad de Alzheimer/metabolismo , Animales , Benzamidas , Encéfalo/metabolismo , Línea Celular Tumoral , Humanos , Mesilato de Imatinib , Masculino , Ratones , Unión Proteica , Inhibidores de Proteínas Quinasas/farmacología , ARN Interferente Pequeño/metabolismo , Ratas , Ratas Sprague-Dawley , Proteínas Recombinantes/metabolismoRESUMEN
The molecular mechanisms governing γ-secretase cleavage specificity are not fully understood. Herein, we demonstrate that extending the transmembrane domain of the amyloid precursor protein-derived C99 substrate in proximity to the cytosolic face strongly influences γ-secretase cleavage specificity. Sequential insertion of leucines or replacement of membrane-anchoring lysines by leucines elevated the production of Aß42, whilst lowering production of Aß40. A single insertion or replacement was sufficient to produce this phenotype, suggesting that the helical length distal to the ε-site is a critical determinant of γ-secretase cleavage specificity. Replacing the lysine at the luminal membrane border (K28) with glutamic acid (K28E) increased Aß37 and reduced Aß42 production. Maintaining a positive charge with an arginine replacement, however, did not alter cleavage specificity. Using two potent and structurally distinct γ-secretase modulators (GSMs), we elucidated the contribution of K28 to the modulatory mechanism. Surprisingly, whilst lowering the potency of the non-steroidal anti-inflammatory drug-type GSM, the K28E mutation converted a heteroaryl-type GSM to an inverse GSM. This result implies the proximal lysine is critical for the GSM mechanism and pharmacology. This region is likely a major determinant for substrate binding and we speculate that modulation of substrate binding is the fundamental mechanism by which GSMs exert their action.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Secretasas de la Proteína Precursora del Amiloide/química , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/química , Precursor de Proteína beta-Amiloide/metabolismo , Enfermedad de Alzheimer/genética , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Secretasas de la Proteína Precursora del Amiloide/genética , Precursor de Proteína beta-Amiloide/genética , Sitios de Unión , Activación Enzimática , Células HEK293 , Humanos , Leucina/metabolismo , Lisina/metabolismo , Proteínas de la Membrana/química , Proteínas de la Membrana/genética , Proteínas de la Membrana/metabolismo , Datos de Secuencia Molecular , Mutagénesis Sitio-Dirigida , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , Especificidad por SustratoRESUMEN
Insulin resistance and impaired glucose homoeostasis are important indicators of Type 2 diabetes and are early risk factors of AD (Alzheimer's disease). An essential feature of AD pathology is the presence of BACE1 (ß-site amyloid precursor protein-cleaving enzyme 1), which regulates production of toxic amyloid peptides. However, whether BACE1 also plays a role in glucose homoeostasis is presently unknown. We have used transgenic mice to analyse the effects of loss of BACE1 on body weight, and lipid and glucose homoeostasis. BACE1-/- mice are lean, with decreased adiposity, higher energy expenditure, and improved glucose disposal and peripheral insulin sensitivity than wild-type littermates. BACE1-/- mice are also protected from diet-induced obesity. BACE1-deficient skeletal muscle and liver exhibit improved insulin sensitivity. In a skeletal muscle cell line, BACE1 inhibition increased glucose uptake and enhanced insulin sensitivity. The loss of BACE1 is associated with increased levels of UCP1 (uncoupling protein 1) in BAT (brown adipose tissue) and UCP2 and UCP3 mRNA in skeletal muscle, indicative of increased uncoupled respiration and metabolic inefficiency. Thus BACE1 levels may play a critical role in glucose and lipid homoeostasis in conditions of chronic nutrient excess. Therefore strategies that ameliorate BACE1 activity may be important novel approaches for the treatment of diabetes.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Ácido Aspártico Endopeptidasas/metabolismo , Dieta , Grasas de la Dieta/administración & dosificación , Regulación de la Expresión Génica/fisiología , Obesidad/metabolismo , Adiposidad , Secretasas de la Proteína Precursora del Amiloide/genética , Animales , Ácido Aspártico Endopeptidasas/genética , Glucemia , Línea Celular , Grasas de la Dieta/efectos adversos , Glucosa/genética , Glucosa/metabolismo , Resistencia a la Insulina , Canales Iónicos , Ratones , Ratones Noqueados , Proteínas Mitocondriales , Mioblastos/metabolismo , Obesidad/inducido químicamente , Obesidad/genética , Proteína Desacopladora 1RESUMEN
γ-secretase inhibitors (GSIs) have been developed to reduce amyloid-ß (Aß) production for the treatment of Alzheimer's disease by inhibiting the cleavage of amyloid precursor protein (APP). However, cross-inhibitory activity on the processing of Notch can cause adverse reactions. To avoid these undesirable effects, γ-secretase modulators (GSMs) are being developed to selectively reduce toxic Aß production without perturbing Notch signaling. As it is also known that GSIs can cause a paradoxical increase of plasma Aß over the baseline after a transient reduction (known as Aß-rebound), we asked if GSMs would cause a similar rebound and what the potential mechanism might be. Our studies were performed with one GSI (LY-450139) and two chemically distinct GSMs. Although LY-450139 caused Aß-rebound as expected in rat plasma, the two GSMs did not. Inhibition of APP processing by LY-450139 induced an accumulation of γ-secretase substrates, α- and ß-C-terminal fragments of APP, but neither GSM caused such an accumulation. In conclusion, we discover that GSMs, unlike GSIs, do not cause Aß-rebound, possibly because of the lack of accumulation of ß-C-terminal fragments. GSMs may be superior to GSIs in the treatment of Alzheimer's disease not only by sparing Notch signaling but also by avoiding Aß-rebound.
Asunto(s)
Alanina/análogos & derivados , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Secretasas de la Proteína Precursora del Amiloide/efectos de los fármacos , Péptidos beta-Amiloides/biosíntesis , Azepinas/farmacología , Alanina/farmacocinética , Alanina/farmacología , Péptidos beta-Amiloides/genética , Animales , Área Bajo la Curva , Azepinas/farmacocinética , Línea Celular , Células Cultivadas , Cromatografía Líquida de Alta Presión , Inhibidores Enzimáticos/farmacocinética , Inhibidores Enzimáticos/farmacología , Humanos , Masculino , Ratones , Ratones Transgénicos , Neuronas/patología , Fragmentos de Péptidos/metabolismo , Placa Amiloide/patología , Ratas , Ratas Sprague-Dawley , Receptores Notch/efectos de los fármacos , Transducción de Señal/efectos de los fármacosRESUMEN
SAR of a novel series of pyridazine-derived γ-secretase modulators is described. Compound 25 was found to be a potent modulator in vitro, which on further profiling, was found to decrease Aß42 and Aß40, and maintain the levels of total Aß. Furthermore, 25 demonstrated excellent pharmacokinetic parameters as well as good CNS penetration in the rat.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Piridazinas/síntesis química , Péptidos beta-Amiloides/metabolismo , Animales , Supervivencia Celular , Células Cultivadas , Activación Enzimática/efectos de los fármacos , Humanos , Concentración 50 Inhibidora , Piridazinas/química , Piridazinas/farmacología , Ratas , Relación Estructura-ActividadRESUMEN
SAR of a novel series of pyridine-derived γ-secretase modulators is described. Compound 5 was found to be a potent modulator in vitro, which on further profiling, was found to decrease Aß42 and Aß40, and maintain (or increase) the levels of total Aß. Furthermore, representative compounds 1 and 5 demonstrated in vivo efficacy to lower Aß42 in the brain without altering Notch processing in the peripheral.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Inhibidores Enzimáticos/farmacología , Piridinas/farmacología , Animales , Disponibilidad Biológica , Inhibidores Enzimáticos del Citocromo P-450 , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Humanos , Estructura Molecular , Piridinas/síntesis química , Piridinas/química , Ratas , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
BACKGROUND: Allosteric modulation of γ-secretase is an attractive therapeutic approach for the treatment of Alzheimer's disease. We recently identified a novel γ-secretase modulator, GSM-10h, which effectively lowers Aß42 production in cells and in amyloid precursor protein transgenic mice. OBJECTIVE: Here, we describe the in vivo characterization of GSM-10h in a model of endogenous Aß production. METHODS: Rats were administered orally with GSM-10h, and the effect on Aß levels in peripheral and central compartments was determined. In addition, the effect of GSM-10h on Notch processing was assessed. RESULTS: Acute administration of GSM-10h to rats causes a dose-dependent decrease in the level of Aß42 in plasma, CSF and brain, with little effect on the level of Aß40 in these compartments. The magnitude of Aß42 lowering in the CSF and brain was further enhanced upon sub-chronic administration of GSM-10h. No deleterious effect on Notch processing was evident in either of these studies. To further explore the dynamics of Aß42 reduction in peripheral and CNS compartments, a time course study was conducted. In all compartments, the decrease in Aß42 was greatest at 6 h after administration of GSM-10h. This decrease in Aß42 was maintained for 9-15 h, after which time Aß42 levels returned to baseline levels. Encouragingly, no rebound in Aß42 levels beyond baseline levels was observed. CONCLUSIONS: These findings support the γ-secretase modulator profile of GSM-10h, and highlight the utility of the rat for assessing the pre-clinical efficacy of γ-secretase modulators.
Asunto(s)
Acetatos/farmacología , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Péptidos beta-Amiloides/metabolismo , Química Encefálica/efectos de los fármacos , Inhibidores Enzimáticos/farmacología , Fragmentos de Péptidos/metabolismo , Piperidinas/farmacología , Péptidos beta-Amiloides/sangre , Péptidos beta-Amiloides/líquido cefalorraquídeo , Animales , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/biosíntesis , Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/genética , Recuento de Células , Corteza Cerebral/citología , Corteza Cerebral/metabolismo , Relación Dosis-Respuesta a Droga , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Proteínas de Homeodominio/biosíntesis , Proteínas de Homeodominio/genética , Masculino , Neuronas/metabolismo , Fragmentos de Péptidos/sangre , Fragmentos de Péptidos/líquido cefalorraquídeo , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Ratas , Ratas Sprague-Dawley , Receptores Notch/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Timo/citología , Timo/efectos de los fármacos , Factor de Transcripción HES-1RESUMEN
BACKGROUND: Cleavage of the amyloid precursor protein (APP) by ß-site APP-cleaving enzyme and γ-secretase results in the generation of amyloid-ß (Aß) peptides that aggregate and deposit as senile plaques in brains of Alzheimer disease patients. Due to the fundamental role γ-secretase plays in the proteolysis of a number of proteins including Notch, pharmacological inhibition of γ-secretase has been associated with mechanism-based toxicities. Therefore, efforts have focussed on the modulation of γ-secretase activity to selectively decrease levels of Aß42 peptide while avoiding deleterious activity on Notch processing. OBJECTIVE: Here, we describe the in vitro and in vivo characterisation of a novel γ-secretase modulator, GSM-10h, and investigate the potential for shorter Aß peptides to induce neurotoxicity in rat primary cortical neurons. METHODS: The effect of GSM-10h on Aß levels was investigated in SH-SY5Y cells expressing mutant APP and in TASTPM mice expressing APP and presenilin-1 mutant transgenes. The effect of GSM-10h on Notch processing was also determined. RESULTS: In cells, GSM-10h decreased levels of Aß42 while concomitantly increasing levels of Aß38 in the absence of effects on Aß40 levels. In TASTPM mice, GSM-10h effectively lowered brain Aß42 and increased brain Aß38, with no effect on Notch signalling. Unlike Aß42, which causes neuronal cell death, neither Aß37 nor Aß38 were neurotoxic. CONCLUSIONS: These findings confirm GSM-10h exhibits the profile of a γ-secretase modulator. In addition, TASTPM mice are shown to be responsive to treatment with a γ-secretase modulator, thereby highlighting the utility of this bitransgenic mouse model in drug discovery efforts focussed on the development of γ-secretase modulators.
Asunto(s)
Acetatos/farmacología , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Secretasas de la Proteína Precursora del Amiloide/genética , Péptidos beta-Amiloides/antagonistas & inhibidores , Precursor de Proteína beta-Amiloide/biosíntesis , Fragmentos de Péptidos/antagonistas & inhibidores , Piperidinas/farmacología , Presenilina-1/biosíntesis , Precursor de Proteína beta-Amiloide/genética , Animales , Muerte Celular/efectos de los fármacos , Corteza Cerebral/citología , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/metabolismo , Ensayo de Inmunoadsorción Enzimática , Citometría de Flujo , Humanos , Ratones , Ratones Transgénicos , Neuronas/efectos de los fármacos , Neuronas/patología , Presenilina-1/genética , ARN Mensajero/biosíntesis , ARN Mensajero/genética , Transgenes/genéticaRESUMEN
This Letter details the SAR of a novel series of piperidine-derived gamma-secretase modulators. Compound 10h was found to be a potent modulator in vitro, which on further profiling, was found to decrease Abeta42, increase Abeta38 and have no effect on Abeta40 levels. Furthermore, 10h demonstrated excellent pharmacokinetic parameters in the mouse, rat and dog in addition to good CNS penetration in the mouse.
Asunto(s)
Acetatos/química , Secretasas de la Proteína Precursora del Amiloide/fisiología , Piperidinas/química , Acetatos/metabolismo , Acetatos/farmacología , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Péptidos beta-Amiloides/antagonistas & inhibidores , Péptidos beta-Amiloides/biosíntesis , Péptidos beta-Amiloides/metabolismo , Animales , Línea Celular Tumoral , Perros , Humanos , Ratones , Fragmentos de Péptidos/antagonistas & inhibidores , Fragmentos de Péptidos/biosíntesis , Fragmentos de Péptidos/metabolismo , Piperidinas/metabolismo , Piperidinas/farmacología , Ratas , Relación Estructura-Actividad , Especificidad por Sustrato/efectos de los fármacosRESUMEN
Inhibition of the aspartyl protease BACE-1 has the potential to deliver a disease-modifying therapy for Alzheimer's disease. Herein, is described a series of potent inhibitors based on an hydroxyethylamine (HEA) transition state mimetic template. These inhibitors interact with the non prime side of the enzyme using a novel edge-to-face interaction with Arg-296.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Arginina/química , Etilaminas/química , Inhibidores de Proteasas/química , Enfermedad de Alzheimer/tratamiento farmacológico , Secretasas de la Proteína Precursora del Amiloide/química , Secretasas de la Proteína Precursora del Amiloide/metabolismo , Animales , Sitios de Unión , Simulación por Computador , Cristalografía por Rayos X , Etilaminas/síntesis química , Etilaminas/uso terapéutico , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/uso terapéutico , Ratas , Relación Estructura-ActividadRESUMEN
Proteolytic processing of the amyloid precursor protein (APP) by beta-secretase, beta-site APP cleaving enzyme (BACE1), is the initial step in the production of the amyloid beta (Abeta) peptide, which is involved in the pathogenesis of Alzheimer's disease. The normal cellular function of the prion protein (PrP(C)), the causative agent of the transmissible spongiform encephalopathies such as Creutzfeldt-Jakob disease in humans, remains enigmatic. Because both APP and PrP(C) are subject to proteolytic processing by the same zinc metalloproteases, we tested the involvement of PrP(C) in the proteolytic processing of APP. Cellular overexpression of PrP(C) inhibited the beta-secretase cleavage of APP and reduced Abeta formation. Conversely, depletion of PrP(C) in mouse N2a cells by siRNA led to an increase in Abeta peptides secreted into the medium. In the brains of PrP knockout mice and in the brains from two strains of scrapie-infected mice, Abeta levels were significantly increased. Two mutants of PrP, PG14 and A116V, that are associated with familial human prion diseases failed to inhibit the beta-secretase cleavage of APP. Using constructs of PrP, we show that this regulatory effect of PrP(C) on the beta-secretase cleavage of APP required the localization of PrP(C) to cholesterol-rich lipid rafts and was mediated by the N-terminal polybasic region of PrP(C) via interaction with glycosaminoglycans. In conclusion, this is a mechanism by which the cellular production of the neurotoxic Abeta is regulated by PrP(C) and may have implications for both Alzheimer's and prion diseases.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Priones/fisiología , Enfermedad de Alzheimer/etiología , Péptidos beta-Amiloides/metabolismo , Animales , Sitios de Unión , Línea Celular , Humanos , Microdominios de Membrana , Ratones , Mutación , Enfermedades por Prión/etiología , Priones/genética , Priones/metabolismoRESUMEN
Our first generation of hydroxyethylamine transition-state mimetic BACE-1 inhibitors allowed us to validate BACE-1 as a key target for Alzheimer's disease by demonstrating amyloid lowering in an animal model, albeit at rather high doses. Finding a molecule from this series which was active at lower oral doses proved elusive and demonstrated the need to find a novel series of inhibitors with improved pharmacokinetics. This Letter describes the discovery of such inhibitors.
Asunto(s)
Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Etilaminas/química , Inhibidores de Proteasas/química , Administración Oral , Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/metabolismo , Animales , Ácido Aspártico Endopeptidasas/metabolismo , Sitios de Unión , Simulación por Computador , Cristalografía por Rayos X , Etilaminas/síntesis química , Etilaminas/farmacología , Humanos , Ratones , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/farmacología , Ratas , Relación Estructura-Actividad , Tiazinas/química , Tiazinas/farmacologíaRESUMEN
Inhibition of the aspartyl protease BACE-1 has the potential to deliver a disease-modifying therapy for Alzheimer's disease. We have recently disclosed a series of transition-state mimetic BACE-1 inhibitors showing nanomolar potency in cell-based assays. Amongst them, GSK188909 (compound 2) had favorable pharmacokinetics and was the first orally bioavailable inhibitor reported to demonstrate brain amyloid lowering in an animal model. In this Letter, we describe the reasons that led us to favor a second generation of inhibitors for further in vivo studies.
Asunto(s)
Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Inhibidores de Proteasas/química , Tiazinas/química , Administración Oral , Enfermedad de Alzheimer/tratamiento farmacológico , Péptidos beta-Amiloides/metabolismo , Animales , Ácido Aspártico Endopeptidasas/metabolismo , Sitios de Unión , Simulación por Computador , Etilaminas/síntesis química , Etilaminas/química , Etilaminas/farmacología , Humanos , Ratones , Inhibidores de Proteasas/farmacocinética , Ratas , Relación Estructura-Actividad , Tiazinas/síntesis química , Tiazinas/farmacocinéticaRESUMEN
Our first generation of hydroxyethylamine BACE-1 inhibitors proved unlikely to provide molecules that would lower amyloid in an animal model at low oral doses. This observation led us to the discovery of a second generation of inhibitors having nanomolar activity in a cell-based assay and with the potential for improved pharmacokinetic profiles. In this Letter, we describe our successful strategy for the optimization of oral bioavailability and also give insights into the design of compounds with the potential for improved brain penetration.
Asunto(s)
Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Etilaminas/química , Inhibidores de Proteasas/química , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/genética , Miembro 1 de la Subfamilia B de Casetes de Unión a ATP/metabolismo , Péptidos beta-Amiloides/metabolismo , Animales , Ácido Aspártico Endopeptidasas/metabolismo , Disponibilidad Biológica , Perros , Etilaminas/síntesis química , Etilaminas/farmacocinética , Ratones , Ratones Noqueados , Inhibidores de Proteasas/síntesis química , Inhibidores de Proteasas/farmacocinética , Ratas , Relación Estructura-ActividadRESUMEN
BACE-1 inhibition has the potential to provide a disease-modifying therapy for the treatment of Alzheimer's disease. Optimization of a first generation of BACE-1 inhibitors led to the discovery of novel hydroxyethylamines (HEAs) bearing a tricyclic nonprime side. These derivatives have nanomolar cell potency and are orally bioavailable.
Asunto(s)
Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Benzotiadiazinas/síntesis química , Óxidos S-Cíclicos/síntesis química , Etilaminas/síntesis química , Administración Oral , Animales , Benzotiadiazinas/farmacocinética , Benzotiadiazinas/farmacología , Disponibilidad Biológica , Óxidos S-Cíclicos/farmacocinética , Óxidos S-Cíclicos/farmacología , Perros , Etilaminas/farmacocinética , Etilaminas/farmacología , Modelos Moleculares , Ratas , Relación Estructura-ActividadRESUMEN
This paper describes the discovery of non-peptidic, potent, and selective hydroxy ethylamine (HEA) inhibitors of BACE-1 by replacement of the prime side of a lead di-amide 2. Inhibitors with nanosmolar potency and high selectivity were identified. Depending on the nature of the P(1)(') and P(2)(') substituents, two different binding modes were observed in X-ray co-crystal structures.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Secretasas de la Proteína Precursora del Amiloide/antagonistas & inhibidores , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Técnicas Químicas Combinatorias , Etilaminas/síntesis química , Etilaminas/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Precursor de Proteína beta-Amiloide/antagonistas & inhibidores , Cristalografía por Rayos X , Etilaminas/química , Humanos , Estructura Molecular , Estereoisomerismo , Relación Estructura-ActividadRESUMEN
Inhibition of the aspartyl protease BACE-1 has the potential to deliver a disease-modifying therapy for Alzheimer's disease. Herein, is described the lead generation effort which resulted, with the support of X-ray crystallography, in the discovery of potent inhibitors based on a hydroxy ethylamine (HEA) transition-state mimetic. These inhibitors were capable of lowering amyloid production in a cell-based assay.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Técnicas Químicas Combinatorias , Etilaminas/síntesis química , Etilaminas/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Precursor de Proteína beta-Amiloide/antagonistas & inhibidores , Cristalografía por Rayos X , Etilaminas/química , Estructura Molecular , Relación Estructura-ActividadRESUMEN
This article is focusing on further optimization of previously described hydroxy ethylamine (HEA) BACE-1 inhibitors obtained from a focused library with the support of X-ray crystallography. Optimization of the non-prime side of our inhibitors and introduction of a 6-membered sultam substituent binding to Asn-294 as well as a fluorine in the C-2 position led to derivatives with nanomolar potency in cell-based assays.
Asunto(s)
Enfermedad de Alzheimer/metabolismo , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Técnicas Químicas Combinatorias , Etilaminas/síntesis química , Etilaminas/farmacología , Enfermedad de Alzheimer/tratamiento farmacológico , Precursor de Proteína beta-Amiloide/antagonistas & inhibidores , Animales , Asparagina/química , Cristalografía por Rayos X , Modelos Animales de Enfermedad , Etilaminas/química , Flúor/química , Ratones , Estructura Molecular , Nanotecnología , Relación Estructura-ActividadRESUMEN
Alzheimer's disease (AD) is a debilitating neurodegenerative disease of the elderly characterized by the loss of memory and other cognitive functions. Currently marketed drugs for the treatment of this disease only offer symptomatic relief, and, consequently, there is a large unmet clinical need for disease-modifying therapies for the treatment of AD. Substantial research efforts are focused on inhibiting the proteases involved in the generation of the amyloidogenic beta-amyloid (A beta) peptide. One of these key proteases, beta-secretase, was identified as a novel transmembrane aspartic protease and named BACE1. Due to its pivotal role in A beta production, many pharmaceutical companies are actively pursuing the challenging task of developing BACE1 inhibitors for evaluation in the clinic.
Asunto(s)
Enfermedad de Alzheimer/tratamiento farmacológico , Ácido Aspártico Endopeptidasas/antagonistas & inhibidores , Inhibidores Enzimáticos/uso terapéutico , Secretasas de la Proteína Precursora del Amiloide , Animales , Diseño de Fármacos , Endopeptidasas , HumanosRESUMEN
ß-Site amyloid precursor protein cleaving enzyme-1 (BACE-1) is a transmembrane aspartic protease that mediates the initial cleavage of the amyloid precursor protein (APP), leading to the generation of amyloid-ß (Aß) peptides that are thought to be causative of Alzheimer's disease (AD). Consequently, inhibition of BACE-1 is an attractive therapeutic approach for the treatment of AD. In general, in vitro biochemical assays to monitor BACE-1 activity have used the extracellular domain of the protein that contains the catalytic active site. This form of BACE-1 is catalytically active at acidic pH and cleaves APP-based peptide substrates at the ß-site. However, this form of BACE-1 does not mimic the natural physiology of BACE-1 and shows minimal activity at pH 6.0, which is more representative of the pH within the intracellular compartments where BACE-1 resides. Moreover, high-throughput screens with recombinant BACE-1 at pH 4.5 have failed to identify tractable leads for drug discovery, and hence, BACE-1 inhibitor development has adopted a rational drug design approach. Here we describe the development and validation of a novel membrane assay comprising full-length BACE-1 with measurable activity at pH 6.0, which could be used for the identification of novel inhibitors of BACE-1.