A novel selective metabotropic glutamate receptor 4 agonist reveals new possibilities for developing subtype selective ligands with therapeutic potential.
Metabotropic glutamate (mGlu) receptors are promising targets to treat numerous brain disorders. So far, allosteric modulators are the only subtype selective ligands, but pure agonists still have strong therapeutic potential. Here, we aimed at investigating the possibility of developing subtype-selective agonists by extending the glutamate-like structure to hit a nonconsensus binding area. We report the properties of the first mGlu4-selective orthosteric agonist, derived from a virtual screening hit, LSP4-2022 using cell-based assays with recombinant mGlu receptors [EC(50): 0.11 ± 0.02, 11.6 ± 1.9, 29.2 ± 4.2 μM (n>19) in calcium assays on mGlu4, mGlu7, and mGlu8 receptors, respectively, with no activity at the group I and -II mGlu receptors at 100 μM]. LSP4-2022 inhibits neurotransmission in cerebellar slices from wild-type but not mGlu4 receptor-knockout mice. In vivo, it possesses antiparkinsonian properties after central or systemic administration in a haloperidol-induced catalepsy test, revealing its ability to cross the blood-brain barrier. Site-directed mutagenesis and molecular modeling was used to identify the LSP4-2022 binding site, revealing interaction with both the glutamate binding site and a variable pocket responsible for selectivity. These data reveal new approaches for developing selective, hydrophilic, and brain-penetrant mGlu receptor agonists, offering new possibilities to design original bioactive compounds with therapeutic potential.
Institut de Génomique Fonctionnelle, CNRS UMR5203, INSERM U661, Universités de Montpellier, 141, Rue de la Cardonille, F34094 Montpellier cedex 5, France. cyril.goudet@igf.cnrs.fr
Cyril
C
Goudet
Bruno
B
Vilar
Tiphanie
T
Courtiol
Thierry
T
Deltheil
Thomas
T
Bessiron
Isabelle
I
Brabet
Nadia
N
Oueslati
Delphine
D
Rigault
Hugues-Olivier
HO
Bertrand
Heather
H
McLean
Hervé
H
Daniel
Marianne
M
Amalric
Francine
F
Acher
Jean-Philippe
JP
Pin
D000818:Animals; D000978:Antiparkinson Agents / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D001665:Binding Sites; D004305:Dose-Response Relationship, Drug; D018690:Excitatory Amino Acid Agonists / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D057809:HEK293 Cells; D006801:Humans; D008024:Ligands; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D018408:Patch-Clamp Techniques; D010721:Phosphinic Acids / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D018094:Receptors, Metabotropic Glutamate / Q000819:agonists* / Q000737:chemistry / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013329:Structure-Activity Relationship; D009435:Synaptic Transmission / Q000187:drug effects
D000978:Antiparkinson Agents; D018690:Excitatory Amino Acid Agonists; C572429:LSP4-2022; D008024:Ligands; D010721:Phosphinic Acids; D018094:Receptors, Metabotropic Glutamate; D011994:Recombinant Proteins; C108823:metabotropic glutamate receptor 4