Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
Add more filters










Database
Language
Publication year range
1.
J Med Chem ; 61(5): 1969-1989, 2018 03 08.
Article in English | MEDLINE | ID: mdl-29397723

ABSTRACT

A group III metabotropic glutamate (mGlu) receptor agonist (PCEP) was identified by virtual HTS. This orthosteric ligand is composed by an l-AP4-derived fragment that mimics glutamate and a chain that binds into a neighboring pocket, offering possibilities to improve affinity and selectivity. Herein we describe a series of derivatives where the distal chain is replaced by an aromatic or heteroaromatic group. Potent agonists were identified, including some with a mGlu4 subtype preference, e.g., 17m (LSP1-2111) and 16g (LSP4-2022). Molecular modeling suggests that aromatic functional groups may bind at either one of the two chloride regulatory sites. These agonists may thus be considered as particular bitopic/dualsteric ligands. 17m was shown to reduce GABAergic synaptic transmission at striatopallidal synapses. We now demonstrate its inhibitory effect at glutamatergic parallel fiber-Purkinje cell synapses in the cerebellar cortex. Although these ligands have physicochemical properties that are markedly different from typical CNS drugs, they hold significant therapeutic potential.


Subject(s)
Binding Sites , Receptors, Metabotropic Glutamate/agonists , Aminobutyrates/pharmacology , Animals , Glutamic Acid/chemistry , Humans , Ligands , Models, Molecular , Molecular Mimicry , Phosphinic Acids/pharmacology , Purkinje Cells/ultrastructure , Synapses/drug effects , Synaptic Transmission/drug effects
2.
Neuropharmacology ; 121: 247-260, 2017 Jul 15.
Article in English | MEDLINE | ID: mdl-28456688

ABSTRACT

In cerebellar cortex, mGlu4 receptors located on parallel fibers play an essential role in normal motor function, but the molecular mechanisms involved are not yet completely understood. Using a strategy combining biochemical and electrophysiological approaches in the rodent cerebellum, we demonstrate that presynaptic mGlu4 receptors control synaptic transmission through an atypical activation of Gαq proteins. First, the Gαq subunit, PLC and PKC signaling proteins present in cerebellar extracts are retained on affinity chromatography columns grafted with different sequences of the cytoplasmic domain of mGlu4 receptor. The i2 loop and the C terminal domain were used as baits, two domains that are known to play a pivotal role in coupling selectivity and efficacy. Second, in situ proximity ligation assays show that native mGlu4 receptors and Gαq subunits are in close physical proximity in cerebellar cortical slices. Finally, electrophysiological experiments demonstrate that the molecular mechanisms underlying mGlu4 receptor-mediated inhibition of transmitter release at cerebellar Parallel Fiber (PF) - Molecular Layer Interneuron (MLI) synapses involves the Gαq-PLC signaling pathway. Taken together, our results provide compelling evidence that, in the rodent cerebellar cortex, mGlu4 receptors act by coupling to the Gαq protein and PLC effector system to reduce glutamate synaptic transmission.


Subject(s)
Cerebellar Cortex/cytology , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Receptors, Metabotropic Glutamate/metabolism , Signal Transduction/physiology , Synaptic Transmission/physiology , Animals , Animals, Newborn , Benzopyrans/pharmacology , Cytoplasm/metabolism , Enzyme Activation/drug effects , Enzyme Inhibitors/pharmacology , Excitatory Amino Acid Agents/pharmacology , Excitatory Postsynaptic Potentials/drug effects , Excitatory Postsynaptic Potentials/genetics , Male , Mice , Mice, Inbred C57BL , Mice, Transgenic , Models, Biological , Nerve Net/drug effects , Propionates/pharmacology , Rats , Rats, Sprague-Dawley , Receptors, Metabotropic Glutamate/genetics , Signal Transduction/drug effects , Synaptic Transmission/drug effects , Synaptic Transmission/genetics
3.
J Physiol ; 590(13): 2977-94, 2012 Jul 01.
Article in English | MEDLINE | ID: mdl-22570379

ABSTRACT

In the rodent cerebellum, pharmacological activation of mGluR4 acutely depresses excitatory synaptic transmission at parallel fibre­Purkinje cell synapses. This depression involves the inhibition of presynaptic calcium (Ca2+) influx that ultimately controls glutamate release. In this study, we investigate the molecular basis of mGluR4-mediated inhibition of presynaptic Ca2+ transients. Our results demonstrate that the mGluR4 effect does not depend on selective inhibition of a specific type of presynaptic voltage-gated Ca2+ channel, but rather involves modulation of all classes of Ca2+ channels present in the presynaptic terminals. In addition, this inhibitory effect does not involve the activation of G protein-activated inwardly rectifying potassium channels, TEA-sensitive potassium channels or two-pore-domain potassium channels. Furthermore, this inhibition does not require pertussis toxin-sensitive G proteins, and is independent of any effect on adenylyl cyclases, protein kinase A, mitogen-activated protein kinases or phosphoinositol-3 kinase activity. Interestingly we found that mGluR4 inhibition of presynaptic Ca2+ influx employs a newly defined signalling pathway, notably that involving the activation of phospholipase C and ultimately protein kinase C.


Subject(s)
Cerebellar Cortex/physiology , Receptors, Metabotropic Glutamate/physiology , Animals , Calcium/physiology , Calcium Channels/physiology , In Vitro Techniques , Male , Protein Kinase C/physiology , Rats , Rats, Sprague-Dawley , Signal Transduction , Synaptic Transmission , Type C Phospholipases/physiology
4.
FASEB J ; 26(4): 1682-93, 2012 Apr.
Article in English | MEDLINE | ID: mdl-22223752

ABSTRACT

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.


Subject(s)
Excitatory Amino Acid Agonists/chemistry , Excitatory Amino Acid Agonists/pharmacology , Ligands , Phosphinic Acids/chemistry , Phosphinic Acids/pharmacology , Receptors, Metabotropic Glutamate/agonists , Animals , Antiparkinson Agents/chemistry , Antiparkinson Agents/metabolism , Antiparkinson Agents/pharmacology , Binding Sites , Dose-Response Relationship, Drug , Excitatory Amino Acid Agonists/metabolism , HEK293 Cells , Humans , Male , Mice , Mice, Knockout , Molecular Structure , Mutagenesis, Site-Directed , Patch-Clamp Techniques , Phosphinic Acids/metabolism , Rats , Rats, Wistar , Receptors, Metabotropic Glutamate/chemistry , Receptors, Metabotropic Glutamate/genetics , Recombinant Proteins/genetics , Recombinant Proteins/metabolism , Structure-Activity Relationship , Synaptic Transmission/drug effects
SELECTION OF CITATIONS
SEARCH DETAIL
...