Discovery of E2730, a novel selective uncompetitive GAT1 inhibitor, as a candidate for anti-seizure medication.
Epilepsia Open
; 8(3): 834-845, 2023 09.
Article
en En
| MEDLINE
| ID: mdl-37052238
ABSTRACT
OBJECTIVE:
As of 2022, 36 anti-seizure medications (ASMs) have been licensed for the treatment of epilepsy, however, adverse effects (AEs) are commonly reported. Therefore, ASMs with a wide margin between therapeutic effects and AEs are preferred over ASMs that are associated with a narrow margin between efficacy and risk of AEs. E2730 was discovered using in vivo phenotypic screening and characterized as an uncompetitive, yet selective, inhibitor of γ-aminobutyric acid (GABA) transporter 1 (GAT1). Here, we describe the preclinical characteristics of E2730.METHODS:
Anti-seizure effects of E2730 were evaluated in several animal models of epilepsy corneal kindling, 6 Hz-44 mA psychomotor seizure, amygdala kindling, Fragile X syndrome, and Dravet syndrome models. Effects of E2730 on motor coordination were assessed in accelerating rotarod tests. The mechanism of action of E2730 was explored by [3 H]E2730 binding assay. The GAT1-selectivity over other GABA transporters was examined by GABA uptake assay of GAT1, GAT2, GAT3, or betaine/GABA transporter 1 (BGT-1) stably expressing HEK293 cells. To further investigate the mechanism for E2730-mediated inhibition of GAT1, in vivo microdialysis and in vitro GABA uptake assays were conducted under conditions of different GABA concentrations.RESULTS:
E2730 showed anti-seizure effects in the assessed animal models with an approximately >20-|fold margin between efficacy and motor incoordination. [3 H]E2730 binding on brain synaptosomal membrane was abolished in GAT1-deficient mice, and E2730 selectively inhibited GAT1-mediated GABA uptake over other GABA transporters. In addition, results of GABA uptake assays showed that E2730-mediated inhibition of GAT1 positively correlated to the level of ambient GABA in vitro. E2730 also increased extracellular GABA concentration in hyperactivated conditions but not under basal levels in vivo.SIGNIFICANCE:
E2730 is a novel, selective, uncompetitive GAT1 inhibitor, which acts selectively under the condition of increasing synaptic activity, contributing to a wide margin between therapeutic effect and motor incoordination.Palabras clave
Texto completo:
1
Colección:
01-internacional
Banco de datos:
MEDLINE
Asunto principal:
Epilepsia
/
Proteínas Transportadoras de GABA en la Membrana Plasmática
/
Anticonvulsivantes
Tipo de estudio:
Prognostic_studies
Límite:
Animals
/
Humans
Idioma:
En
Revista:
Epilepsia Open
Año:
2023
Tipo del documento:
Article
País de afiliación:
Japón