RESUMEN
Impaired expression of GABA transporters (GATs) is closely related to the pathogenesis of among others Parkinson's disease and epilepsy. As such, lipophilic nipecotic acid analogs have been extensively studied as GAT1-addressing drugs and radioligands but suffer from limited brain uptake due to the zwitterionic properties of the nipecotic acid moiety. Bioisosteric replacement of the carboxylic acid group is a promising strategy to improve the brain uptake, though it requires knowledge on the binding of these isosteres to GAT1. To screen nipecotic acid isosteres for their affinity to GAT1 in a time- and cost-effective manner, this research aims to develop a molecular imprinted polymer (MIP) that mimics the natural binding site of GAT1 and can act as an alternative screening tool to the current radiometric and mass spectrometry cellular-based assays. To this end, a nipecotic acid MIP was created using the electropolymerization of ortho-phenylenediamine (oPD) by cyclic voltammetry (CV). The optimization of the generated receptor layer was achieved by varying the scan rate (50-250 mV/s) and number of CV cycles (5-12), yielding an optimized MIP with an average imprinting factor of 2.6, a linear range of 1-1000 nm, and a theoretical LOD of 0.05 nm, as analyzed by electrical impedance spectroscopy (EIS). Selectivity studies facilitated the investigation of major binding interactions between the MIP and the substrate, building an experimental model that compares characteristics of various analogs. Results from this model indicate that the substrate carboxylic acid group plays a more important role in binding than an amine group, after comparing the binding of cyclohexanecarboxylic acid (average IF of 1.7) and piperidine (average IF of 0.46). The research culminates in a discussion regarding the feasibility of the in vitro model, comparing the synthetic system against the biological performance of GAT1. Thus, evaluating if it is possible to generate a synthetic GAT1 mimic, and if so, provide directions for follow-up research.
Asunto(s)
Polímeros Impresos Molecularmente , Ácidos Nipecóticos , Polímeros Impresos Molecularmente/química , Ácidos Nipecóticos/química , Ácidos Nipecóticos/metabolismo , Humanos , Proteínas Transportadoras de GABA en la Membrana Plasmática/metabolismo , Proteínas Transportadoras de GABA en la Membrana Plasmática/química , Impresión MolecularRESUMEN
Gamma-Aminobutyric Acid (GABA) inhibitory neurotransmitter departs an energetic role in brain signalling system. Levels of GABA in the brain influence human behaviour, diminishes in the degree of GABA can cause seizures, depression, Parkinson's. To put it plainly, it plays a basic part in the significant issues of mind. It is exceptionally important to cure the issues linked to GABA. Writing overview proposed that nipecotic acid is an intense GABA reuptake inhibitor. This scaffold is likewise present in one of the promoted anticonvulsant drugs 'Tiagabine'. Tiagabine is only drug in the market which works through this mechanism however the medication is regulated with one more prescription for the synergistic impact. Nipecotic acid has several disadvantages such as it can't cross the blood-brain barrier because of its hydrophilic and zwitterionic nature. To avoid this problem nipecotic acid scaffold hybrids with the different aromatic groups can enhance the physical (lipophilicity) as well as biological properties of the resultant compound. So, there is a dire requirement for compounds that work through this mechanism. Several medicinal chemists and researchers are already working in this field and developed outstanding newer molecules. This review article compiles these developed new hybrids along with design strategies, structure-activity relationship, and biological activity as well as in silico studies. This review also demonstrates the synthesis of nipecotic acid and the core mechanism through which nipecotic acid acts as a GABA reuptake inhibitor.
Asunto(s)
Inhibidores de Recaptación de GABA , Ácidos Nipecóticos , Anticonvulsivantes/química , Humanos , Ácidos Nipecóticos/química , Ácidos Nipecóticos/farmacología , Tiagabina , Ácido gamma-AminobutíricoRESUMEN
Nipecotic acid is considered to be one of the most potent inhibitors of neuronal and glial-aminobutyric acid (GABA) uptake in vitro. Due to its hydrophilic nature, nipecotic acid does not readily cross the blood-brain barrier (BBB). Large neutral amino acids (LAT1)-knotted nipecotic acid prodrug was designed and synthesized with the aim to enhance the BBB permeation by the use of carrier-mediated transport. The synthesized prodrug was tested in animal models of Pentylenetetrazole (PTZ)-induced convulsions in mice. Further pain studies were carried out followed by neurotoxicity estimation by writhing and rota-rod test respectively. HPLC data suggests that the synthesized prodrug has improved penetration through BBB. Nipecotic acid-L-serine ester prodrug with considerable anti-epileptic activity, and the ability to permeate the BBB has been successfully synthesized. Graphical Abstract.
Asunto(s)
Barrera Hematoencefálica/metabolismo , Ácidos Nipecóticos/química , Ácidos Nipecóticos/síntesis química , Profármacos/química , Profármacos/síntesis química , Serina/química , Serina/síntesis química , Animales , Anticonvulsivantes/síntesis química , Anticonvulsivantes/química , Anticonvulsivantes/farmacología , Transporte Biológico/efectos de los fármacos , Ésteres/síntesis química , Ésteres/química , Ésteres/farmacología , Interacciones Hidrofóbicas e Hidrofílicas , Masculino , Ratones , Ácidos Nipecóticos/farmacología , Pentilenotetrazol/síntesis química , Pentilenotetrazol/química , Pentilenotetrazol/farmacología , Profármacos/farmacología , Convulsiones/tratamiento farmacológicoRESUMEN
Pathogenic mutations in the copper transporter ATP7B have been hypothesized to affect its protein interaction landscape contributing to loss of function and, thereby, to hepatic copper toxicosis in Wilson disease. Although targeting mutant interactomes was proposed as a therapeutic strategy, druggable interactors for rescue of ATP7B mutants remain elusive. Using proteomics, we found that the frequent H1069Q substitution promotes ATP7B interaction with HSP70, thus accelerating endoplasmic reticulum (ER) degradation of the mutant protein and consequent copper accumulation in hepatic cells. This prompted us to use an HSP70 inhibitor as bait in a bioinformatics search for structurally similar Food and Drug Administration-approved drugs. Among the hits, domperidone emerged as an effective corrector that recovered trafficking and function of ATP7B-H1069Q by impairing its exposure to the HSP70 proteostatic network. Our findings suggest that HSP70-mediated degradation can be safely targeted with domperidone to rescue ER-retained ATP7B mutants and, hence, to counter the onset of Wilson disease.
Asunto(s)
ATPasas Transportadoras de Cobre/genética , ATPasas Transportadoras de Cobre/metabolismo , Domperidona/farmacología , Proteínas HSP70 de Choque Térmico/metabolismo , Degeneración Hepatolenticular/genética , Bencimidazoles/química , Bencimidazoles/farmacología , Células Cultivadas , Cobre/metabolismo , Domperidona/química , Retículo Endoplásmico/efectos de los fármacos , Retículo Endoplásmico/metabolismo , Proteínas HSP70 de Choque Térmico/antagonistas & inhibidores , Células Hep G2 , Hepatocitos/metabolismo , Degeneración Hepatolenticular/tratamiento farmacológico , Degeneración Hepatolenticular/metabolismo , Degeneración Hepatolenticular/patología , Humanos , Mutación Missense , Ácidos Nipecóticos/química , Ácidos Nipecóticos/farmacología , Transporte de Proteínas/efectos de los fármacos , Transporte de Proteínas/genética , Proteómica/métodosRESUMEN
Potential mGAT4 inhibitors derived from the lead substance (S)-SNAP-5114 have been synthesized and characterized for their inhibitory potency. Variations from the parent compound included the substitution of one of its aromatic 4-methoxy and 4-methoxyphenyl groups, respectively, with a more polar moiety, including a carboxylic acid, alcohol, nitrile, carboxamide, sulfonamide, aldehyde or ketone function, or amino acid partial structures. Furthermore, it was investigated how the substitution of more than one of the aromatic 4-methoxy groups affects the potency and selectivity of the resulting compounds. Among the synthesized test substances (S)-1-{2-[(4-formylphenyl)bis(4-methoxyphenyl)-methoxy]ethyl}piperidine-3-carboxylic acid, that features a carbaldehyde function in place of one of the aromatic 4-methoxy moieties of (S)-SNAP-5114, was found to have a pIC50 value of 5.89±0.07, hence constituting a slightly more potent mGAT4 inhibitor than the parent substance while showing comparable subtype selectivity.
Asunto(s)
Inhibidores Enzimáticos/farmacología , Inhibidores de Recaptación de GABA/farmacología , N-Acetilglucosaminiltransferasas/antagonistas & inhibidores , Ácidos Nipecóticos/farmacología , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/química , Inhibidores de Recaptación de GABA/síntesis química , Inhibidores de Recaptación de GABA/química , Células HEK293 , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Estructura Molecular , N-Acetilglucosaminiltransferasas/metabolismo , Ácidos Nipecóticos/síntesis química , Ácidos Nipecóticos/química , Relación Estructura-ActividadRESUMEN
PURPOSE: 4-(3S)-3-[5-(2-[18F]-fluoroethoxy)pyridin-3-yl]-3-[({(3R)-1-[3-(piperidin-4-yl)propanoyl]-piperidin-3-yl}carbonyl)amino]propanoic acid ([18F]GP1) is a radiotracer developed for targeted imaging of activated platelet glycoprotein IIb/IIIa receptors with positron emission tomography/computed tomography (PET/CT) in acute thromboembolism. We evaluated here radiation dosimetry of [18F]GP1 in humans. PROCEDURES: We studied 30 subjects (10 with deep vein thrombosis, 10 with pulmonary embolism, and 10 with arterial thromboembolism) who had signs or symptoms of acute thromboembolism, and were confirmed to have thromboembolic foci by imaging studies. Dynamic whole-body PET/CT images were acquired for up to 140â¯min after injection of 250â¯MBq of [18F]GP1. Radiation absorbed dose and effective dose were calculated using the OLINDA/EXM software. RESULTS: [18F]GP1 PET images showed high initial uptake of the tracer in the heart, spleen, kidney, and liver. [18F]GP1 activity was cleared by hepatobiliary and urinary excretion. The organ receiving the highest radiation absorbed dose (mGy/MBq) was the urinary bladder (0.0884⯱â¯0.0458), followed by upper large intestine (0.0498⯱â¯0.0189), small intestine (0.0454⯱â¯0.0166), and kidneys (0.0350⯱â¯0.0231). The effective dose (mSv/MBq) was 0.0212⯱â¯0.0027 (ICRP 103). ED was not significantly different between the three disease groups (pâ¯=â¯0.94). A 45-minute voiding reduced the urinary bladder wall radiation dose to 0.0495⯱â¯0.0140â¯mGy/MBq, and effective dose (ICRP 103) to 0.0186⯱â¯0.0030. CONCLUSIONS: [18F]GP1 has favorable radiation dosimetry profile for clinical PET/CT imaging. The ED is comparable to commonly used 18F PET tracers.
Asunto(s)
Radioisótopos de Flúor/farmacocinética , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/metabolismo , Tomografía de Emisión de Positrones/métodos , Radiofármacos/farmacocinética , Tromboembolia/metabolismo , Enfermedad Aguda , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Ácidos Nipecóticos/química , Complejo GPIIb-IIIa de Glicoproteína Plaquetaria/antagonistas & inhibidores , Estudios Prospectivos , Piridinas/química , Trazadores Radiactivos , Radiometría , Tromboembolia/diagnóstico por imagen , Tromboembolia/patología , Distribución Tisular , Adulto JovenRESUMEN
A new class of nipecotic acid and guvacine derivatives has been synthesized and characterized for their inhibitory potency at mGAT1-4 and binding affinity for mGAT1. Compounds of the described class are defined by a four-carbon-atom allenyl spacer connecting the nitrogen atom of the nipecotic acid or guvacine head with an aromatic residue. Among the compounds investigated, the mixture of nipecotic acid derivatives rac-{(Ra )-1-[4-([1,1':2',1''-terphenyl]-2-yl)buta-2,3-dien-1-yl](3R)-piperidine-3-carboxylic acid} and rac-{(Sa )-1-[4-([1,1':2',1''-terphenyl]-2-yl)buta-2,3-dien-1-yl](3R)-piperidine-3-carboxylic acid} (21 p), possessing an o-terphenyl residue, was identified as highly selective and the most potent mGAT1 inhibitor in this study. For the (R)-nipecotic acid derived form of 21 p, the inhibitory potency in [3 H]GABA uptake assays was determined as pIC50 =6.78±0.08, and the binding affinity in MS Binding Assays as pKi =7.10±0.12. The synthesis of the designed compounds was carried out by a two-step procedure, generating the allene moiety via allenylation of terminal alkynes which allows broad variation of the terminal phenyl and biphenyl subunit.
Asunto(s)
Alquenos/síntesis química , Alquenos/farmacología , Inhibidores Enzimáticos/síntesis química , Inhibidores Enzimáticos/farmacología , N-Acetilglucosaminiltransferasas/antagonistas & inhibidores , Ácidos Nicotínicos/farmacología , Ácidos Nipecóticos/farmacología , Alquenos/química , Animales , Relación Dosis-Respuesta a Droga , Inhibidores Enzimáticos/química , Células HEK293 , Humanos , Ratones , Estructura Molecular , N-Acetilglucosaminiltransferasas/metabolismo , Ácidos Nicotínicos/síntesis química , Ácidos Nicotínicos/química , Ácidos Nipecóticos/síntesis química , Ácidos Nipecóticos/química , Relación Estructura-ActividadRESUMEN
To discover new, potent, and selective inhibitors for the murine gamma-aminobutyric acid transporter 4 (mGAT4), the structure-activity relationship (SAR) study of a new cis-alkene analog family based on DDPM-1457 [(S)-2], which previously showed promising inhibitory potency at and subtype selectivity for mGAT4, was conducted. To uncover the importance of the differences between the trans- and the cis-alkene moiety in the spacer, the present publication describes the synthesis of the new compounds via catalytic hydrogenation with Lindlar's catalyst. The biological results collected by the SAR study revealed that analog rac-7j characterized by a four-instead of a three-carbon atom spacer with a cis double bond applying to the majority of the studied compounds displays a surprisingly high potency at mGAT1 (pIC50â¯=â¯6.00⯱â¯0.04) and at the same time a reasonable potency at mGAT4 (pIC50â¯=â¯4.82).
Asunto(s)
Alquenos/farmacología , Inhibidores de Recaptación de GABA/farmacología , Ácidos Nipecóticos/farmacología , Alquenos/síntesis química , Alquenos/química , Animales , Diseño de Fármacos , Proteínas Transportadoras de GABA en la Membrana Plasmática/metabolismo , Inhibidores de Recaptación de GABA/síntesis química , Inhibidores de Recaptación de GABA/química , Células HEK293 , Humanos , Ratones , Ácidos Nipecóticos/síntesis química , Ácidos Nipecóticos/química , Estereoisomerismo , Relación Estructura-Actividad , Tiagabina/farmacologíaRESUMEN
A screening of compound libraries based on nipecotic acid derivatives with lipophilic residues attached to the scarcely explored 5-position of the core structure was used for the search of new inhibitors of the γ-aminobutyric acid (GABA) transporterâ 1 (mGAT1). The generated compound libraries, which were based on hydrazone chemistry commonly used in dynamic combinatorial chemistry but rendered pseudostatic, were screened for their binding affinities toward mGAT1 by means of MS Binding Assays. With nipecotic acid derived hydrazone rac-16 h [rac-(3R,5S)-{5-[(E)-2-{[5-(2-phenylethynyl)thiophen-2-yl]methylidene}hydrazin-1-yl]piperidine-3-carboxylic acid}-sodium chloride (1/2)], one hit was found and evaluated displaying sub-micromolar potency (pKi =6.62±0.04) and a noncompetitive interaction mode at mGAT1. By bearing a 5-(2-phenylethynyl)thiophen-2-yl residue attached to the 5-position of nipecotic acid via a three-atom spacer, compound rac-16 h contains a structural moiety so far unprecedented for these kinds of bioactive molecules, and complements novel 5-substituted nipecotic acid derived ligands of mGAT1 revealed in a recently published screening campaign. This new class of ligands, with an inhibition mode distinct from that of benchmark mGAT1 inhibitors, could serve as research tools for investigations of mGAT1-mediated GABA transport.
Asunto(s)
Proteínas Transportadoras de GABA en la Membrana Plasmática/metabolismo , Inhibidores de Recaptación de GABA/química , Hidrazonas/química , Ácidos Nipecóticos/química , Bibliotecas de Moléculas Pequeñas/química , Espectrometría de Masa por Ionización de Electrospray/métodos , Unión Competitiva , Cromatografía Líquida de Alta Presión , Evaluación Preclínica de Medicamentos/métodos , Inhibidores de Recaptación de GABA/metabolismo , Células HEK293 , Humanos , Hidrazonas/metabolismo , Ligandos , Estructura Molecular , Bibliotecas de Moléculas Pequeñas/metabolismo , Relación Estructura-ActividadRESUMEN
The γ-aminobutyric acid (GABA) transporter mGAT4 represents a promising drug target for the treatment of epilepsy and other neurological disorders; however, the lack of highly potent and selective inhibitors for mGAT4 still retards its pharmacological elucidation. Herein, the generation and screening of pseudostatic combinatorial hydrazone libraries at the murine GABA transporter mGAT4 for the search of novel GABA uptake inhibitors is described. The hydrazone libraries contained more than 1100 compounds derived from nipecotic acid derivatives substituted at the 5-position instead, as common, at the 1-position of the core structure. Two hits were found and evaluated, which display potencies in the lower micromolar range at mGAT4 and its human equivalent hGAT3. These compounds possess a lipophilic moiety derived from a biphenyl residue attached to the 5-position of the hydrophilic nipecotic acid moiety via a three-atom spacer. Thus, the novel structures with potencies close to that of the bench mark mGAT4 inhibitor (S)-SNAP-5114 add new insights into the structure-activity relationship of mGAT4 inhibitors and could provide a promising starting point for the development of new mGAT4 inhibitors with even higher potencies.
Asunto(s)
Proteínas Transportadoras de GABA en la Membrana Plasmática/metabolismo , Inhibidores de Recaptación de GABA/farmacología , Hidrazonas/farmacología , Ácidos Nipecóticos/farmacología , Bibliotecas de Moléculas Pequeñas/farmacología , Animales , Inhibidores de Recaptación de GABA/síntesis química , Inhibidores de Recaptación de GABA/química , Células HEK293 , Humanos , Hidrazonas/síntesis química , Hidrazonas/química , Ratones , Estructura Molecular , Ácidos Nipecóticos/síntesis química , Ácidos Nipecóticos/química , Bibliotecas de Moléculas Pequeñas/síntesis química , Bibliotecas de Moléculas Pequeñas/química , Relación Estructura-ActividadRESUMEN
Our study presents the synthesis and structure-activity relationship (SAR) of novel N-substituted nipecotic acid derivatives closely related to DDPM-1457 [(S)-2a], a chemically stable analog of (S)-SNAP-5114 (1), in the pursuit of finding new and potent mGAT4 selective inhibitors. Iminium ion chemistry served as key step for the preparation of the desired, new N-substituted nipecotic acid derivatives containing a variety of different heterocycles attached to the nipecotic acid moiety via a trans-alkene spacer. The target compounds were characterized with regard to their potency at and subtype selectivity for the GABA transporters mGAT1-mGAT4.
Asunto(s)
Alquenos/farmacología , Inhibidores de Recaptación de GABA/farmacología , Ácidos Nipecóticos/farmacología , Ácido gamma-Aminobutírico/metabolismo , Alquenos/química , Relación Dosis-Respuesta a Droga , Inhibidores de Recaptación de GABA/síntesis química , Inhibidores de Recaptación de GABA/química , Células HEK293 , Humanos , Estructura Molecular , Ácidos Nipecóticos/síntesis química , Ácidos Nipecóticos/química , Relación Estructura-ActividadRESUMEN
A series of nipecotic acid derivatives with new azo benzene based photoswitchable N-substituents was synthesized and characterized in their ( E)- and ( Z)-form for their functional inhibitory activity at γ-aminobutyric acid transporters subtype 1 (GAT1), the most common γ-aminobutyric acid (GABA) transporter subtype in the central nervous system (CNS). This led to the identification of the first photoswitchable ligands exhibiting a moderate uptake inhibition of GABA in their ( E)- but distinctive higher inhibitory potency in their ( Z)-form resulting from photoirradiation. For the most efficient photoactivatable nipecotic acid derivative displaying an N-but-3-yn-1-yl linker with a terminal diphenyldiazene unit, an inhibitory potency of 4.65 ± 0.05 (pIC50) was found for its ( E)-form. which increased by almost two log units up to 6.38 ± 0.04 when irradiated. The effect of this photoswitchable mGAT1 inhibitor has also been evaluated and confirmed in patch-clamp recordings in acute hippocampal slices from mice.
Asunto(s)
Compuestos Azo/química , Compuestos Azo/farmacología , Procesos Fotoquímicos , Ácido gamma-Aminobutírico/metabolismo , Transporte Biológico/efectos de los fármacos , Células HEK293 , Humanos , Simulación del Acoplamiento Molecular , N-Acetilglucosaminiltransferasas/antagonistas & inhibidores , N-Acetilglucosaminiltransferasas/química , N-Acetilglucosaminiltransferasas/metabolismo , Ácidos Nipecóticos/química , Conformación Proteica , Relación Estructura-ActividadRESUMEN
In this study, we present the synthesis and structure-activity relationships (SAR) of novel N-substituted nipecotic acid derivatives closely related to (S)-SNAP-5114 (2) in the pursuit of finding new and potent mGAT4 selective inhibitors. By the use of iminium ion chemistry, a series of new N-substituted nipecotic acid derivatives containing a variety of heterocycles, and an alkyne spacer were synthesized. Biological evaluation of the prepared compounds showed, how the inhibitory potency and subtype selectivity for the murine GABA transporters (mGATs) were influenced by the performed modifications.
Asunto(s)
Alquinos/química , Proteínas Transportadoras de GABA en la Membrana Plasmática/química , Proteínas Transportadoras de GABA en la Membrana Plasmática/metabolismo , Inhibidores de Recaptación de GABA/síntesis química , Ácidos Nipecóticos/química , Animales , Inhibidores de Recaptación de GABA/metabolismo , Células HEK293 , Humanos , Ratones , Ácidos Nipecóticos/metabolismo , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Relación Estructura-Actividad , Ácido gamma-Aminobutírico/metabolismoRESUMEN
BACKGROUND: Nipecotic acid is considered to be one of the most potent inhibitors of neuronal and glial γ-aminobutyric acid (GABA) uptake in vitro. However, nipecotic acid does not readily cross the blood-brain barrier (BBB) following peripheral administration, owing to its hydrophilic nature. OBJECTIVE: A series of substituted acetonaphthones tethered nipecotic acid derivatives were designed and synthesized with an aim to improve the lipophilicity and the blood-brain barrier (BBB) permeation. METHODS: Synthesized compounds were tested in mice models of PTZ, pilocarpine, and DMCM induced epilepsy, in vivo. The rota-rod test was performed to determine the acute neurotoxicity of the potential leads (4a, 4b, and 4i). These potential hybrids were also evaluated for their ability to cross the BBB by an in vitro parallel artificial membrane permeability BBB assay (PAMPA-BBB). The leads were subjected to in silico molecular docking and dynamics studies on homology modelled protein of human GABA (γ-amino butyric acid) transporter 1 (GAT1) and prediction of their pharmacokinetic properties. RESULT: Amongst the synthesized derivatives, compounds 3a, 3b, 3i, 4a, 4b, and 4i exhibited increased latency of seizures against subcutaneous pentylenetetrazole (scPTZ) induced seizures in mice. Derivatives 4a, 4b, 4i were more effective compared to nipecotic acid ester counterparts 3a, 3b and 3i placing the importance of the presence of free carboxyl group in the centre. The findings revealed that 4i was comparatively more permeable (Pe= 8.89) across BBB than the standard tiagabine (Pe= 7.86). In silico studies proved the consensual interactions of compound 4i with the active binding pocket. CONCLUSION: Some nipecotic acid-acetonaphthone hybrids with considerable anti-epileptic activity, drug like properties and the ability to permeate the BBB have been successfully synthesized.
Asunto(s)
Anticonvulsivantes/uso terapéutico , Epilepsia/tratamiento farmacológico , Naftalenos/uso terapéutico , Ácidos Nipecóticos/uso terapéutico , Animales , Anticonvulsivantes/síntesis química , Anticonvulsivantes/química , Barrera Hematoencefálica/metabolismo , Modelos Animales de Enfermedad , Drosophila , Diseño de Fármacos , Femenino , Proteínas Transportadoras de GABA en la Membrana Plasmática/química , Inhibidores de Recaptación de GABA/síntesis química , Inhibidores de Recaptación de GABA/química , Inhibidores de Recaptación de GABA/uso terapéutico , Humanos , Interacciones Hidrofóbicas e Hidrofílicas , Masculino , Ratones , Simulación del Acoplamiento Molecular , Simulación de Dinámica Molecular , Naftalenos/síntesis química , Naftalenos/química , Ácidos Nipecóticos/síntesis química , Ácidos Nipecóticos/química , TiagabinaRESUMEN
We recently reported the development of a novel inhibitor of Rho-mediated gene transcription (1, CCG-203971) that is efficacious in multiple animal models of acute fibrosis, including scleroderma, when given intraperitoneally. The modest in vivo potency and poor pharmacokinetics (PK) of this lead, however, make it unsuitable for long term efficacy studies. We therefore undertook a systematic medicinal chemistry effort to improve both the metabolic stability and the solubility of 1, resulting in the identification of two analogs achieving over 10-fold increases in plasma exposures in mice. We subsequently showed that one of these analogs (8f, CCG-232601) could inhibit the development of bleomycin-induced dermal fibrosis in mice when administered orally at 50mg/kg, an effect that was comparable to what we had observed earlier with 1 at a 4-fold higher IP dose.
Asunto(s)
Ácidos Nipecóticos/farmacocinética , Ácidos Nipecóticos/uso terapéutico , Factor Rho/antagonistas & inhibidores , Esclerodermia Sistémica/tratamiento farmacológico , Piel/efectos de los fármacos , Activación Transcripcional/efectos de los fármacos , Administración Oral , Animales , Modelos Animales de Enfermedad , Fibrosis , Células HEK293 , Humanos , Ratones , Ácidos Nipecóticos/administración & dosificación , Ácidos Nipecóticos/química , Factor Rho/metabolismo , Esclerodermia Sistémica/genética , Esclerodermia Sistémica/metabolismo , Esclerodermia Sistémica/patología , Elemento de Respuesta al Suero/efectos de los fármacos , Piel/metabolismo , Piel/patología , Transactivadores/antagonistas & inhibidores , Transactivadores/metabolismoRESUMEN
A new scaffold of highly potent and mGAT1-selective inhibitors has been developed. Compounds in this class are characterized by an alkyne-type spacer connecting nipecotic acid with an aromatic moiety. Preliminary evaluations made it apparent that a nipecotic acid derivative with an N-butynyl linker and a terminal 2-biphenyl residue exhibiting a binding affinity (pKi ) of 7.61±0.03 to mGAT1 and uptake inhibition (pIC50 ) of 7.00±0.06 selective for mGAT1 could serve as a hit compound. Docking calculations for compounds based on this structure in an hGAT1 homology modeling study indicated binding affinities similar to or even higher than that of the well-known mGAT1 inhibitor tiagabine. Synthesis of the designed compounds was readily carried out by two consecutive cross-coupling reactions, giving flexible access to variously substituted biphenyl subunits. With an appropriate substitution pattern of the biphenyl moiety, the binding affinity of enantiopure (R)-nipecotic acid derivatives to mGAT1 increased to pKi =8.33±0.01, and the uptake inhibitory potency up to pIC50 =7.72±0.02.
Asunto(s)
Proteínas Transportadoras de GABA en la Membrana Plasmática/química , Inhibidores de Recaptación de GABA/química , Ácidos Nipecóticos/química , Sitios de Unión , Proteínas Transportadoras de GABA en la Membrana Plasmática/metabolismo , Inhibidores de Recaptación de GABA/síntesis química , Inhibidores de Recaptación de GABA/metabolismo , Células HEK293 , Humanos , Concentración 50 Inhibidora , Simulación del Acoplamiento Molecular , Ácidos Nipecóticos/síntesis química , Ácidos Nipecóticos/metabolismo , Isoformas de Proteínas/antagonistas & inhibidores , Isoformas de Proteínas/metabolismo , Estructura Terciaria de Proteína , Relación Estructura-ActividadRESUMEN
Despite significant recent progress in the area of translational genomics of neuroblastoma, the overall survival rates for children with high-risk NB continue to be not more than 5 years due to tumor relapse and/or drug-resistant tumors. Herein we report on the development of a neuroblastoma targeting nanometric (130-150 nm) circulation stable liposomal system prepared from a novel nipecotic acid-derived cationic amphiphile (NACA). The size ranges of liposomes (130-150 nm) were confirmed by both dynamic light scattering and transmission electron microscopy. The findings in the gel electrophoresis assay revealed that siRNAs encapsulated within the liposomes of NACA (with 90% entrapment efficiency) are protected from attack by RNase. Cellular uptake experiments using FAM-siRNA loaded liposomes of NACA showed the liposomal entry in human neuroblastoma cells (IMR-32) to be mediated via the GABAA receptor. CDC20siRNA-loaded liposomes of NACA caused significantly higher CDC20 gene silencing efficiency in IMR-32 cells compared to CDC20 gene knockdown efficiency mediated by CDC20siRNA-loaded control non-targeting liposomes (NTL). The findings in the annexin-V binding based flow cytometric apoptosis assay and MTT-based cellular cytotoxicity assay support the notion that pronounced (80%) neuroblastoma cell death upon treatment with CDC20siRNA & PTX co-loaded liposomes of NACA presumably originates from enhanced apoptosis of cells. Importantly, intravenously administered CDC20siRNA & PTX co-loaded liposomes of NACA significantly inhibited growth of xenografted human neuroblastoma in athymic nude mice. The presently disclosed strategy of co-delivering potent anticancer siRNA and small molecule chemotherapeutics using liposomes of NACA opens a new door for combating the dreaded disease of neuroblastoma.
Asunto(s)
Proteínas Cdc20/genética , Liposomas , Neuroblastoma/tratamiento farmacológico , Ácidos Nipecóticos/química , Paclitaxel/administración & dosificación , ARN Interferente Pequeño/genética , Animales , Línea Celular Tumoral , Humanos , Ratones , Ratones Desnudos , Ensayos Antitumor por Modelo de XenoinjertoRESUMEN
For the enantiopure synthesis of novel chiral GABA uptake inhibitors, nipecotic acid (1) is an important key precursor. To characterize accurately the pharmacological activity of these interesting target compounds, the determination of the correct enantiomeric purity of nipecotic acid as the starting material is indispensable. In this report, a sensitive high-performance liquid chromatography (HPLC) based method for the separation and quantitation of both enantiomers of nipecotic acid as 1-(7-nitrobenzo[c][1,2,5]oxadiazol-4-yl) derivatives (5) on a Chiralpak ID-3 column (Daicel, Illkirch, France) was established. UV/Vis-detection at 490 nm was chosen to ensure a selective determination of even highly enantioenriched samples. Reliability was demonstrated by validation of specificity, linearity, lower limit of quantification (LLOQ), accuracy, and precision. By spiking highly enantiopure samples with small amounts of racemic rac-5, it was proven that the established HPLC method is able to detect even slight changes in enantiomeric excess (ee) values. Thus, accurate determination of ee values up to 99.87% ee for (R)-5 and 99.86% ee for (S)-5 over a linear concentration range of 1-1500 µM for (R)-5 and of 1-1455 µM for (S)-5 could be demonstrated.
Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Ácidos Nipecóticos/química , Nitrocompuestos/química , Oxadiazoles/química , Reproducibilidad de los Resultados , EstereoisomerismoRESUMEN
A new series of potent and selective mGAT1 inhibitors has been identified, featuring a nipecotic acid residue and an N-butenyl linker with a 2-biphenyl residue at the ω-position. Docking, combined with MD calculations, revealed a binding mode for the new compounds similar to that of tiagabine, the only mGAT1 inhibitor currently approved as antiepileptic drug. For the synthesis, a Suzuki-Miyaura cross-coupling reaction was used as a key step by which variously substituted biaryl subunits were assembled. Biological evaluation revealed several compounds that possess binding affinities and inhibitory potencies toward mGAT1, together with subtype selectivities against mGAT2-mGAT4 that were similar to or even higher than those for tiagabine. A derivative carrying the 2',4'-dichloro-2-biphenyl moiety attached to N-but-3-enylnipecotic acid at the terminal position of the linker chain was found to be the most potent binder, with the racemic form of the compound displaying a binding affinity of 8.05±0.13 (pKi ), while the Râ enantiomer exhibited an affinity value of 8.33±0.06 (pKi ).
Asunto(s)
Proteínas Transportadoras de GABA en la Membrana Plasmática/efectos de los fármacos , Ácidos Nipecóticos/síntesis química , Animales , Proteínas Transportadoras de GABA en la Membrana Plasmática/química , Humanos , Ratones , Modelos Moleculares , Ácidos Nipecóticos/química , Ácidos Nipecóticos/farmacologíaRESUMEN
Screening a library of small-molecule compounds using a cell line expressing human GABA transporter 3 (hGAT3) in a [(3)H]GABA uptake assay identified isatin derivatives as a new class of hGAT3 inhibitors. A subsequent structure-activity relationship (SAR) study led to the identification of hGAT3-selective inhibitors (i.e., compounds 20 and 34) that were superior to the reference hGAT3 inhibitor, (S)-SNAP-5114, in terms of potency (low micromolar IC50 values) and selectivity (>30-fold selective for hGAT3 over hGAT1/hGAT2/hBGT1). Further pharmacological characterization of compound 20 (5-(thiophen-2-yl)indoline-2,3-dione) revealed a noncompetitive mode of inhibition at hGAT3. This suggests that this compound class, which has no structural resemblance to GABA, has a binding site different from the substrate, GABA. This was supported by a molecular modeling study that suggested a unique binding site that matched the observed selectivity, inhibition kinetics, and SAR of the compound series. These compounds are the most potent GAT3 inhibitors reported to date that provide selectivity for GAT3 over other GABA transporter subtypes.