TY - JOUR
T1 - Identification and Structure-Function Study of Positive Allosteric Modulators of Kainate Receptors
AU - Larsen, Anja Probst
AU - Fièvre, Sabine
AU - Frydenvang, Karla
AU - Francotte, Pierre
AU - Pirotte, Bernard
AU - Kastrup, Jette Sandholm
AU - Mulle, Christophe
N1 - Copyright © 2017 by The American Society for Pharmacology and Experimental Therapeutics.
PY - 2017/6
Y1 - 2017/6
N2 - Kainate receptors (KARs) consist of a class of ionotropic glutamate receptors, which exert diverse pre- and postsynaptic functions through complex signaling regulating the activity of neural circuits. Whereas numerous small-molecule positive allosteric modulators of the ligand-binding domain of (S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propanoic acid (AMPA) receptors have been reported, no such ligands are available for KARs. In this study, we investigated the ability of three benzothiadiazine-based modulators to potentiate glutamate-evoked currents at recombinantly expressed KARs. 4-cyclopropyl-7-fluoro-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1- dioxide (BPAM344) potentiated glutamate-evoked currents of GluK2a 21-fold at the highest concentration tested (200 mM), with an EC50 of 79 μM. BPAM344 markedly decreased desensitization kinetics (from 5.5 to 775 ms), whereas it only had a minor effect on deactivation kinetics. 4-cyclopropyl-7-hydroxy-3,4-dihydro-2H- 1,2,4-benzothiadiazine 1,1-dioxide (BPAM521) potentiated the recorded peak current amplitude of GluK2a 12-fold at a concentration of 300 μM with an EC50 value of 159 μM, whereas no potentiation of the glutamate-evoked response was observed for 7-chloro-4-(2-fluoroethyl)-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (BPAM121) at the highest concentration of modulator tested (300 μM). BPAM344 (100 μM) also potentiated the peak current amplitude of KAR subunits GluK3a (59-fold), GluK2a (15- fold), GluK1b (5-fold), as well as the AMPA receptor subunit GluA1i (5-fold). X-ray structures of the three modulators in the GluK1 ligand-binding domain were determined, locating two modulatorbinding sites at the GluK1 dimer interface. In conclusion, this study may enable the design of newpositive allostericmodulators selective for KARs, whichwill be of great interest for further investigation of the function of KARs in vivo andmay prove useful for pharmacologically controlling the activity of neuronal networks.
AB - Kainate receptors (KARs) consist of a class of ionotropic glutamate receptors, which exert diverse pre- and postsynaptic functions through complex signaling regulating the activity of neural circuits. Whereas numerous small-molecule positive allosteric modulators of the ligand-binding domain of (S)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propanoic acid (AMPA) receptors have been reported, no such ligands are available for KARs. In this study, we investigated the ability of three benzothiadiazine-based modulators to potentiate glutamate-evoked currents at recombinantly expressed KARs. 4-cyclopropyl-7-fluoro-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1- dioxide (BPAM344) potentiated glutamate-evoked currents of GluK2a 21-fold at the highest concentration tested (200 mM), with an EC50 of 79 μM. BPAM344 markedly decreased desensitization kinetics (from 5.5 to 775 ms), whereas it only had a minor effect on deactivation kinetics. 4-cyclopropyl-7-hydroxy-3,4-dihydro-2H- 1,2,4-benzothiadiazine 1,1-dioxide (BPAM521) potentiated the recorded peak current amplitude of GluK2a 12-fold at a concentration of 300 μM with an EC50 value of 159 μM, whereas no potentiation of the glutamate-evoked response was observed for 7-chloro-4-(2-fluoroethyl)-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (BPAM121) at the highest concentration of modulator tested (300 μM). BPAM344 (100 μM) also potentiated the peak current amplitude of KAR subunits GluK3a (59-fold), GluK2a (15- fold), GluK1b (5-fold), as well as the AMPA receptor subunit GluA1i (5-fold). X-ray structures of the three modulators in the GluK1 ligand-binding domain were determined, locating two modulatorbinding sites at the GluK1 dimer interface. In conclusion, this study may enable the design of newpositive allostericmodulators selective for KARs, whichwill be of great interest for further investigation of the function of KARs in vivo andmay prove useful for pharmacologically controlling the activity of neuronal networks.
KW - Allosteric Regulation
KW - Animals
KW - Dose-Response Relationship, Drug
KW - Excitatory Amino Acid Agonists
KW - HEK293 Cells
KW - Humans
KW - Protein Structure, Secondary
KW - Rats
KW - Receptors, Kainic Acid
KW - Structure-Activity Relationship
KW - X-Ray Diffraction
KW - Journal Article
U2 - 10.1124/mol.116.107599
DO - 10.1124/mol.116.107599
M3 - Journal article
C2 - 28360094
SN - 0026-895X
VL - 91
SP - 576
EP - 585
JO - Molecular Pharmacology
JF - Molecular Pharmacology
IS - 6
ER -