Discovery of a subtype selective inhibitor of the human betaine/GABA transporter 1 (BGT-1) with a non-competitive pharmacological profile.
The γ-aminobutyric acid (GABA) transporters (GATs) are essential regulators of the activity in the GABAergic system through their continuous uptake of the neurotransmitter from the synaptic cleft and extrasynaptic space. Four GAT subtypes have been identified to date, each displaying different pharmacological properties and expression patterns. The present study focus on the human betaine/GABA transporter 1 (BGT-1), which has recently emerged as a new target for treatment of epilepsy. However, the lack of selective inhibitors of this transporter has impaired the exploration of this potential considerably. With the objective of identifying novel compounds displaying selectivity for BGT-1, we performed a screening of a small compound library at cells expressing BGT-1 using a [(3)H]GABA uptake assay. The screening resulted in the identification of the compound N-(1-benzyl-4-piperidinyl)-2,4-dichlorobenzamide (BPDBA), a selective inhibitor of the human BGT-1 transporter with a non-competitive profile exhibiting no significant inhibitory activity at the other three human GAT subtypes. The selectivity profile of the compound was subsequently confirmed at cells expressing the four mouse GAT subtypes. Thus, BPDBA constitutes a potential useful pharmacological tool compound for future explorations of the function of the BGT-1 subtype.
['Kragholm|Bolette|B|', 'Kvist|Trine|T|', 'Madsen|Karsten K|KK|', 'Jørgensen|Lars|L|', 'Vogensen|Stine B|SB|', 'Schousboe|Arne|A|', 'Clausen|Rasmus P|RP|', 'Jensen|Anders A|AA|', 'Bräuner-Osborne|Hans|H|']
D000818:Animals D001549:Benzamides D001622:Betaine D016466:CHO Cells D002352:Carrier Proteins D006224:Cricetinae D016208:Databases, Factual D050485:GABA Plasma Membrane Transport Proteins D057809:HEK293 Cells D057166:High-Throughput Screening Assays D006801:Humans D008564:Membrane Potentials D051379:Mice D009557:Nipecotic Acids D010880:Piperidines D054852:Small Molecule Libraries D000078308:Tiagabine
betaine/GABA transporter 1 GABA GABA transporter GABA transporter BGT-1 γ-aminobutyric acid GAT N-(1-benzyl-4-piperidinyl)-2,4-dichlorobenzamide BPDBA (R)-N-[4,4-bis(3-methyl-2-thienyl)-3-butenyl]nipecotic acid 1-[2-[tris(4-methoxyphenyl)methoxy]ethyl]-(S)-3-piperidine carboxylic acid CHO CNS Chinese hamster ovary DMEM DPBS Dulbecco's Modified Eagle Medium Dulbecco's Phosphate Buffered Saline EF-1502 FLIPR™ Membrane Potential FMP GABA transporters HBSS HEK Hanks’ Balanced Saline Solution N-[4,4-bis(3-methyl-2-thienyl)-3-butenyl]-3-hydroxy-4-(methylamino)-4,5,6,7-tetrahydrobenzo[d]isoxazol-3-ol Non-competitive inhibition profile SNAP-5114 central nervous system human embryonic kidney tiagabine