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Andrés A. Trabanco - One of the best experts on this subject based on the ideXlab platform.
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Journal of Medicinal Chemistry - Covalent Allosteric Probe for the Metabotropic Glutamate Receptor 2: Design, Synthesis, and Pharmacological Characterization
Journal of medicinal chemistry, 2018Co-Authors: Maarten L.j. Doornbos, Andrés A. Trabanco, José María Cid, Hilde Lavreysen, Luc Peeters, Laura Pérez-benito, Laura H. Heitman, Xuesong Wang, Sophie C. Vermond, Gary TresadernAbstract:Covalent labeling of G protein-coupled Receptors (GPCRs) by small molecules is a powerful approach to understand binding modes, mechanism of action, pharmacology, and even facilitate structure elucidation. We report the first covalent positive allosteric modulator (PAM) for a class C GPCR, the mGlu2 Receptor. Three putatively covalent mGlu2 PAMs were designed and synthesized. Pharmacological characterization identified 2 to bind the Receptor covalently. Computational modeling combined with Receptor mutagenesis revealed T7917.29×30 as the likely position of covalent interaction. We show how this covalent ligand can be used to characterize the PAM binding mode and that it is a valuable tool compound in studying Receptor function and binding kinetics. Our findings advance the understanding of the mGlu2 PAM interaction and suggest that 2 is a valuable probe for further structural and chemical biology approaches.
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molecular mechanism of positive allosteric modulation of the metabotropic Glutamate Receptor 2 by jnj 46281222
British Journal of Pharmacology, 2016Co-Authors: Maarten L.j. Doornbos, Andrés A. Trabanco, José María Cid, Hilde Lavreysen, Gary Tresadern, Ilse Biesmans, Laura Perezbenito, Thea Mulderkrieger, Adriaan P. IjzermanAbstract:BACKGROUND AND PURPOSE Allosteric modulation of the mGlu2 Receptor is a potential strategy for treatment of various neurological and psychiatric disorders. Here, we describe the in vitro characterization of the mGlu2 positive allosteric modulator (PAM) JNJ-46281222 and its radiolabelled counterpart [(3) H]-JNJ-46281222. Using this novel tool, we also describe the allosteric effect of orthosteric Glutamate binding and the presence of a bound G protein on PAM binding and use computational approaches to further investigate the binding mode. EXPERIMENTAL APPROACH We have used radioligand binding studies, functional assays, site-directed mutagenesis, homology modelling and molecular dynamics to study the binding of JNJ-46281222. KEY RESULTS JNJ-46281222 is an mGlu2 -selective, highly potent PAM with nanomolar affinity (KD = 1.7 nM). Binding of [(3) H]-JNJ-46281222 was increased by the presence of Glutamate and greatly reduced by the presence of GTP, indicating the preference for a G protein bound state of the Receptor for PAM binding. Its allosteric binding site was visualized and analysed by a computational docking and molecular dynamics study. The simulations revealed amino acid movements in regions expected to be important for activation. The binding mode was supported by [(3) H]-JNJ-46281222 binding experiments on mutant Receptors. CONCLUSION AND IMPLICATIONS Our results obtained with JNJ-46281222 in unlabelled and tritiated form further contribute to our understanding of mGlu2 allosteric modulation. The computational simulations and mutagenesis provide a plausible binding mode with indications of how the ligand permits allosteric activation. This study is therefore of interest for mGlu2 and class C Receptor drug discovery.
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Molecular mechanism of positive allosteric modulation of the metabotropic Glutamate Receptor 2 by JNJ‐46281222
British journal of pharmacology, 2016Co-Authors: Maarten L.j. Doornbos, Andrés A. Trabanco, José María Cid, Hilde Lavreysen, Gary Tresadern, Laura Pérez-benito, Thea Mulder-krieger, Ilse Biesmans, Adriaan P. Ijzerman, Laura H. HeitmanAbstract:BACKGROUND AND PURPOSE Allosteric modulation of the mGlu2 Receptor is a potential strategy for treatment of various neurological and psychiatric disorders. Here, we describe the in vitro characterization of the mGlu2 positive allosteric modulator (PAM) JNJ-46281222 and its radiolabelled counterpart [(3) H]-JNJ-46281222. Using this novel tool, we also describe the allosteric effect of orthosteric Glutamate binding and the presence of a bound G protein on PAM binding and use computational approaches to further investigate the binding mode. EXPERIMENTAL APPROACH We have used radioligand binding studies, functional assays, site-directed mutagenesis, homology modelling and molecular dynamics to study the binding of JNJ-46281222. KEY RESULTS JNJ-46281222 is an mGlu2 -selective, highly potent PAM with nanomolar affinity (KD = 1.7 nM). Binding of [(3) H]-JNJ-46281222 was increased by the presence of Glutamate and greatly reduced by the presence of GTP, indicating the preference for a G protein bound state of the Receptor for PAM binding. Its allosteric binding site was visualized and analysed by a computational docking and molecular dynamics study. The simulations revealed amino acid movements in regions expected to be important for activation. The binding mode was supported by [(3) H]-JNJ-46281222 binding experiments on mutant Receptors. CONCLUSION AND IMPLICATIONS Our results obtained with JNJ-46281222 in unlabelled and tritiated form further contribute to our understanding of mGlu2 allosteric modulation. The computational simulations and mutagenesis provide a plausible binding mode with indications of how the ligand permits allosteric activation. This study is therefore of interest for mGlu2 and class C Receptor drug discovery.
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Molecular determinants of positive allosteric modulation of the human metabotropic Glutamate Receptor 2.
British journal of pharmacology, 2015Co-Authors: A Farinha, Andrés A. Trabanco, José María Cid, Hilde Lavreysen, Luc Peeters, B Russo, Stefan Masure, Gary TresadernAbstract:Background and Purpose The activation of the metabotropic Glutamate Receptor 2 (mGlu2) reduces Glutamatergic transmission in brain regions where excess excitatory signalling is implicated in disorders such as anxiety and schizophrenia. Positive allosteric modulators (PAMs) can provide a fine-tuned potentiation of these Receptors' function and are being investigated as a novel therapeutic approach. An extensive set of mutant human mGlu2 Receptors were used to investigate the molecular determinants that are important for positive allosteric modulation at this Receptor. Experimental Approach Site-directed mutagenesis, binding and functional assays were employed to identify amino acids important for the activity of nine PAMs. The data from the radioligand binding and mutagenesis studies were used with computational docking to predict a binding mode at an mGlu2 Receptor model based on the recent structure of the mGlu1 Receptor. Key Results New amino acids in TM3 (R635, L639, F643), TM5 (L732) and TM6 (W773, F776) were identified for the first time as playing an important role in the activity of mGlu2 PAMs. Conclusions and Implications This extensive study furthers our understanding of positive allosteric modulation of the mGlu2 Receptor and can contribute to improved future design of mGlu2 PAMs.
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Metabotropic Glutamate Receptor 2 Activators
Small Molecule Therapeutics for Schizophrenia, 2014Co-Authors: José María Cid, Andrés A. Trabanco, Hilde LavreysenAbstract:Schizophrenia is a common and severe, often disabling psychiatric illness of unknown aetiology that affects approximately 24 million people worldwide. The illness is characterized by symptomatology comprising positive symptoms (hallucinations and delusional behaviours), negative symptoms (anhedonia, social withdrawal and apathy) and cognitive dysfunction (diminished capacity for learning, memory and executive function). Current pharmacological treatments are effective at alleviating positive symptoms but have limited impact on negative symptoms and cognitive deficits. Furthermore, the extrapyramidal symptoms, hyperprolactinemia and metabolic syndrome, including substantial weight gain, are typical side effects limiting the value of many of these drugs for patients. Thus, drugs that better serve the patient population by effectively treating all symptoms with improved safety and tolerability remain a critical unmet need. Modulation of the metabotropic Glutamate type 2 (mGlu2) Receptor has emerged as a promising mechanism for the treatment of CNS diseases, with the potential to provide a new and more effective avenue for the treatment of schizophrenia.
David M Lovinger - One of the best experts on this subject based on the ideXlab platform.
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operant self stimulation of thalamic terminals in the dorsomedial striatum is constrained by metabotropic Glutamate Receptor 2
Neuropsychopharmacology, 2020Co-Authors: Kari A Johnson, Lucas Voyvodic, Gabriel C Loewinger, Yolanda Mateo, David M LovingerAbstract:: Dorsal striatal manipulations including stimulation of dopamine release and activation of medium spiny neurons (MSNs) are sufficient to drive reinforcement-based learning. Glutamatergic innervation of the striatum by the cortex and thalamus is a critical determinant of MSN activity and local regulation of dopamine release. However, the relationship between striatal Glutamatergic afferents and behavioral reinforcement is not well understood. We evaluated the reinforcing properties of optogenetic stimulation of thalamostriatal terminals, which are associated with vesicular Glutamate transporter 2 (Vglut2) expression, in the dorsomedial striatum (DMS), a region implicated in goal-directed behaviors. In mice expressing channelrhodopsin-2 (ChR2) under control of the Vglut2 promoter, optical stimulation of the DMS reinforced operant lever-pressing behavior. Mice also acquired operant self-stimulation of thalamostriatal terminals when ChR2 expression was virally targeted to the intralaminar thalamus. Stimulation trains that supported operant responding evoked dopamine release in the DMS and excitatory postsynaptic currents in DMS MSNs. Our previous work demonstrated that the presynaptic G protein-coupled Receptor metabotropic Glutamate Receptor 2 (mGlu2) robustly inhibits Glutamate and dopamine release induced by activation of thalamostriatal afferents. Thus, we examined the regulation of thalamostriatal self-stimulation by mGlu2. Administration of an mGlu2/3 agonist or an mGlu2-selective positive allosteric modulator reduced self-stimulation. Conversely, blockade of these Receptors increased thalamostriatal self-stimulation, suggesting that endogenous activation of these Receptors negatively modulates the reinforcing properties of thalamostriatal activity. These findings demonstrate that stimulation of thalamic terminals in the DMS is sufficient to reinforce a self-initiated action, and that thalamostriatal reinforcement is constrained by mGlu2 activation.
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operant self stimulation of thalamic terminals in the dorsomedial striatum is constrained by metabotropic Glutamate Receptor 2
bioRxiv, 2019Co-Authors: Kari A Johnson, Lucas Voyvodic, Yolanda Mateo, David M LovingerAbstract:ABSTRACT Dorsal striatal manipulations including stimulation of dopamine release and activation of medium spiny neurons (MSNs) are sufficient to drive reinforcement-based learning. Glutamatergic innervation of the dorsal striatum by both the cortex and thalamus is a critical determinant of both MSN activity and local regulation of dopamine release. However, the relationship between Glutamatergic inputs to the striatum and behavioral reinforcement is not well understood. We sought to evaluate the reinforcing properties of optogenetic stimulation of thalamostriatal terminals, which are associated with vesicular Glutamate transporter 2 (Vglut2) expression, in the dorsomedial striatum (DMS), a region implicated in goal-directed operant behaviors. In mice expressing channelrhodopsin-2 (ChR2) under control of the Vglut2 promoter, brief optical stimulation of the DMS reinforces operant lever-pressing behavior. Mice also acquire operant self-stimulation of thalamic terminals in the DMS when ChR2 expression is virally targeted to the intralaminar thalamus. Because the presynaptic G protein-coupled Receptor metabotropic Glutamate Receptor 2 (mGlu2) robustly inhibits Glutamate and dopamine release induced by activation of thalamostriatal afferents, we examined the regulation of thalamostriatal self-stimulation by mGlu2. We find that administration of an mGlu2/3 agonist or an mGlu2-selective positive allosteric modulator reduces self-stimulation. In contrast, blockade of these Receptors increases thalamostriatal self-stimulation, suggesting that endogenous activation of these Receptors negatively modulates the reinforcing properties of thalamostriatal activity. These findings demonstrate that stimulation of thalamic terminals in the DMS is sufficient to reinforce a self-initiated action, and that thalamostriatal reinforcement is constrained by mGlu2 activation.
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Age-dependent impairment of metabotropic Glutamate Receptor 2-dependent long-term depression in the mouse striatum by chronic ethanol exposure.
Alcohol (Fayetteville N.Y.), 2019Co-Authors: Kari A Johnson, Daniel J. Liput, Gregg E. Homanics, David M LovingerAbstract:Abstract Chronic alcohol exposure is associated with increased reliance on behavioral strategies involving the dorsolateral striatum (DLS), including habitual or stimulus-response behaviors. Presynaptic G protein-coupled Receptors (GPCRs) on cortical and thalamic inputs to the DLS inhibit Glutamate release, and alcohol-induced disruption of presynaptic GPCR function represents a mechanism by which alcohol could disinhibit DLS neurons and thus bias toward use of DLS-dependent behaviors. Metabotropic Glutamate Receptor 2 (mGlu2) is a Gi/o-coupled GPCR that robustly modulates Glutamate transmission in the DLS, inducing long-term depression (LTD) at both cortical and thalamic synapses. Loss of mGlu2 function has recently been associated with increased ethanol seeking and consumption, but the ability of alcohol to produce adaptations in mGlu2 function in the DLS has not been investigated. We exposed male C57Bl/6J mice to a 2-week chronic intermittent ethanol (CIE) paradigm followed by a brief withdrawal period, then used whole-cell patch clamp recordings of Glutamatergic transmission in the striatum to assess CIE effects on mGlu2-mediated synaptic plasticity. We report that CIE differentially disrupts mGlu2-mediated long-term depression in the DLS vs. dorsomedial striatum (DMS). Interestingly, CIE-induced impairment of mGlu2-LTD in the dorsolateral striatum is only observed when alcohol exposure occurs during adolescence. Incubation of striatal slices from CIE-exposed adolescent mice with a positive allosteric modulator of mGlu2 fully rescues mGlu2-LTD. In contrast to the 2-week CIE paradigm, acute exposure of striatal slices to ethanol concentrations that mimic ethanol levels during CIE exposure fails to disrupt mGlu2-LTD. We did not observe a reduction of mGlu2 mRNA or protein levels following CIE exposure, suggesting that alcohol effects on mGlu2 occur at the functional level. Our findings contribute to growing evidence that adolescents are uniquely vulnerable to certain alcohol-induced neuroadaptations, and identify enhancement of mGlu2 activity as a strategy to reverse the effects of adolescent alcohol exposure on DLS physiology.
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Metabotropic Glutamate Receptor 2 inhibits thalamically-driven Glutamate and dopamine release in the dorsal striatum.
Neuropharmacology, 2017Co-Authors: Kari A Johnson, Yolanda Mateo, David M LovingerAbstract:The striatum plays critical roles in action control and cognition, and activity of striatal neurons is driven by Glutamatergic input. Inhibition of Glutamatergic inputs to projection neurons and interneurons of the striatum by presynaptic G protein-coupled Receptors (GPCRs) stands to modulate striatal output and striatum-dependent behaviors. Despite knowledge that a substantial number of Glutamatergic inputs to striatal neurons originate in the thalamus, most electrophysiological studies assessing GPCR modulation do not differentiate between effects on corticostriatal and thalamostriatal transmission, and synaptic inhibition is frequently assumed to be mediated by activation of GPCRs on corticostriatal terminals. We used optogenetic techniques and recently-discovered pharmacological tools to dissect the effects of a prominent presynaptic GPCR, metabotropic Glutamate Receptor 2 (mGlu2), on corticostriatal vs. thalamostriatal transmission. We found that an agonist of mGlu2 and mGlu3 induces long-term depression (LTD) at synapses onto MSNs from both the cortex and the thalamus. Thalamostriatal LTD is selectively blocked by an mGlu2-selective negative allosteric modulator and reversed by application of an antagonist following LTD induction. Activation of mGlu2/3 also induces LTD of thalamostriatal transmission in striatal cholinergic interneurons (CINs), and pharmacological activation of mGlu2/3 or selective activation of mGlu2 inhibits CIN-mediated dopamine release evoked by selective stimulation of thalamostriatal inputs. Thus, mGlu2 activation exerts effects on striatal physiology that extend beyond modulation of corticostriatal synapses, and has the potential to influence cognition and striatum-related disorders via inhibition of thalamus-derived Glutamate and dopamine release.
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Metabotropic Glutamate Receptor 2 Positive Allosteric Modulators: Closing the Gate on Drug Abuse?
Biological psychiatry, 2015Co-Authors: Kari A Johnson, David M LovingerAbstract:Abnormally high levels of extracellular Glutamate, the principal excitatory neurotransmitter in the central nervous system, have been implicated in elevated drug seeking and taking as well as drug addiction (1). Presynaptic metabotropic Glutamate Receptors (mGluRs) can limit Glutamate release by acting as autoReceptors on Glutamatergic terminals (2). Among the eight subtypes of mGluRs, group II (mGluR2 and mGluR3) and group III (mGluR4, mGluR7, and mGluR8) are known to act as autoReceptors at excitatory synapses in the mammalian brain. Group II mGluRs have received considerable attention in recent years as contributing factors and therapeutic targets for drug abuse disorders (2). For example, several studies demonstrated that agonists of group II mGluRs decrease operant self-administration of drugs, including cocaine, alcohol, nicotine, and methamphetamine. In addition, activation of group II mGluRs attenuates cue-induced reinstatement of cocaine, heroin, alcohol, and methamphetamine self-administration as well as drug priming–induced reinstatement of nicotine, methamphetamine, and cocaine seeking. Conversely, an antagonist of group II mGluRs increases alcohol drinking (3). There is an evolving idea that presynaptic group II mGluRs may provide a “gatekeeper” function, limiting Glutamate release at key synapses in addiction circuitry.
Kari A Johnson - One of the best experts on this subject based on the ideXlab platform.
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operant self stimulation of thalamic terminals in the dorsomedial striatum is constrained by metabotropic Glutamate Receptor 2
Neuropsychopharmacology, 2020Co-Authors: Kari A Johnson, Lucas Voyvodic, Gabriel C Loewinger, Yolanda Mateo, David M LovingerAbstract:: Dorsal striatal manipulations including stimulation of dopamine release and activation of medium spiny neurons (MSNs) are sufficient to drive reinforcement-based learning. Glutamatergic innervation of the striatum by the cortex and thalamus is a critical determinant of MSN activity and local regulation of dopamine release. However, the relationship between striatal Glutamatergic afferents and behavioral reinforcement is not well understood. We evaluated the reinforcing properties of optogenetic stimulation of thalamostriatal terminals, which are associated with vesicular Glutamate transporter 2 (Vglut2) expression, in the dorsomedial striatum (DMS), a region implicated in goal-directed behaviors. In mice expressing channelrhodopsin-2 (ChR2) under control of the Vglut2 promoter, optical stimulation of the DMS reinforced operant lever-pressing behavior. Mice also acquired operant self-stimulation of thalamostriatal terminals when ChR2 expression was virally targeted to the intralaminar thalamus. Stimulation trains that supported operant responding evoked dopamine release in the DMS and excitatory postsynaptic currents in DMS MSNs. Our previous work demonstrated that the presynaptic G protein-coupled Receptor metabotropic Glutamate Receptor 2 (mGlu2) robustly inhibits Glutamate and dopamine release induced by activation of thalamostriatal afferents. Thus, we examined the regulation of thalamostriatal self-stimulation by mGlu2. Administration of an mGlu2/3 agonist or an mGlu2-selective positive allosteric modulator reduced self-stimulation. Conversely, blockade of these Receptors increased thalamostriatal self-stimulation, suggesting that endogenous activation of these Receptors negatively modulates the reinforcing properties of thalamostriatal activity. These findings demonstrate that stimulation of thalamic terminals in the DMS is sufficient to reinforce a self-initiated action, and that thalamostriatal reinforcement is constrained by mGlu2 activation.
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operant self stimulation of thalamic terminals in the dorsomedial striatum is constrained by metabotropic Glutamate Receptor 2
bioRxiv, 2019Co-Authors: Kari A Johnson, Lucas Voyvodic, Yolanda Mateo, David M LovingerAbstract:ABSTRACT Dorsal striatal manipulations including stimulation of dopamine release and activation of medium spiny neurons (MSNs) are sufficient to drive reinforcement-based learning. Glutamatergic innervation of the dorsal striatum by both the cortex and thalamus is a critical determinant of both MSN activity and local regulation of dopamine release. However, the relationship between Glutamatergic inputs to the striatum and behavioral reinforcement is not well understood. We sought to evaluate the reinforcing properties of optogenetic stimulation of thalamostriatal terminals, which are associated with vesicular Glutamate transporter 2 (Vglut2) expression, in the dorsomedial striatum (DMS), a region implicated in goal-directed operant behaviors. In mice expressing channelrhodopsin-2 (ChR2) under control of the Vglut2 promoter, brief optical stimulation of the DMS reinforces operant lever-pressing behavior. Mice also acquire operant self-stimulation of thalamic terminals in the DMS when ChR2 expression is virally targeted to the intralaminar thalamus. Because the presynaptic G protein-coupled Receptor metabotropic Glutamate Receptor 2 (mGlu2) robustly inhibits Glutamate and dopamine release induced by activation of thalamostriatal afferents, we examined the regulation of thalamostriatal self-stimulation by mGlu2. We find that administration of an mGlu2/3 agonist or an mGlu2-selective positive allosteric modulator reduces self-stimulation. In contrast, blockade of these Receptors increases thalamostriatal self-stimulation, suggesting that endogenous activation of these Receptors negatively modulates the reinforcing properties of thalamostriatal activity. These findings demonstrate that stimulation of thalamic terminals in the DMS is sufficient to reinforce a self-initiated action, and that thalamostriatal reinforcement is constrained by mGlu2 activation.
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Age-dependent impairment of metabotropic Glutamate Receptor 2-dependent long-term depression in the mouse striatum by chronic ethanol exposure.
Alcohol (Fayetteville N.Y.), 2019Co-Authors: Kari A Johnson, Daniel J. Liput, Gregg E. Homanics, David M LovingerAbstract:Abstract Chronic alcohol exposure is associated with increased reliance on behavioral strategies involving the dorsolateral striatum (DLS), including habitual or stimulus-response behaviors. Presynaptic G protein-coupled Receptors (GPCRs) on cortical and thalamic inputs to the DLS inhibit Glutamate release, and alcohol-induced disruption of presynaptic GPCR function represents a mechanism by which alcohol could disinhibit DLS neurons and thus bias toward use of DLS-dependent behaviors. Metabotropic Glutamate Receptor 2 (mGlu2) is a Gi/o-coupled GPCR that robustly modulates Glutamate transmission in the DLS, inducing long-term depression (LTD) at both cortical and thalamic synapses. Loss of mGlu2 function has recently been associated with increased ethanol seeking and consumption, but the ability of alcohol to produce adaptations in mGlu2 function in the DLS has not been investigated. We exposed male C57Bl/6J mice to a 2-week chronic intermittent ethanol (CIE) paradigm followed by a brief withdrawal period, then used whole-cell patch clamp recordings of Glutamatergic transmission in the striatum to assess CIE effects on mGlu2-mediated synaptic plasticity. We report that CIE differentially disrupts mGlu2-mediated long-term depression in the DLS vs. dorsomedial striatum (DMS). Interestingly, CIE-induced impairment of mGlu2-LTD in the dorsolateral striatum is only observed when alcohol exposure occurs during adolescence. Incubation of striatal slices from CIE-exposed adolescent mice with a positive allosteric modulator of mGlu2 fully rescues mGlu2-LTD. In contrast to the 2-week CIE paradigm, acute exposure of striatal slices to ethanol concentrations that mimic ethanol levels during CIE exposure fails to disrupt mGlu2-LTD. We did not observe a reduction of mGlu2 mRNA or protein levels following CIE exposure, suggesting that alcohol effects on mGlu2 occur at the functional level. Our findings contribute to growing evidence that adolescents are uniquely vulnerable to certain alcohol-induced neuroadaptations, and identify enhancement of mGlu2 activity as a strategy to reverse the effects of adolescent alcohol exposure on DLS physiology.
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Metabotropic Glutamate Receptor 2 inhibits thalamically-driven Glutamate and dopamine release in the dorsal striatum.
Neuropharmacology, 2017Co-Authors: Kari A Johnson, Yolanda Mateo, David M LovingerAbstract:The striatum plays critical roles in action control and cognition, and activity of striatal neurons is driven by Glutamatergic input. Inhibition of Glutamatergic inputs to projection neurons and interneurons of the striatum by presynaptic G protein-coupled Receptors (GPCRs) stands to modulate striatal output and striatum-dependent behaviors. Despite knowledge that a substantial number of Glutamatergic inputs to striatal neurons originate in the thalamus, most electrophysiological studies assessing GPCR modulation do not differentiate between effects on corticostriatal and thalamostriatal transmission, and synaptic inhibition is frequently assumed to be mediated by activation of GPCRs on corticostriatal terminals. We used optogenetic techniques and recently-discovered pharmacological tools to dissect the effects of a prominent presynaptic GPCR, metabotropic Glutamate Receptor 2 (mGlu2), on corticostriatal vs. thalamostriatal transmission. We found that an agonist of mGlu2 and mGlu3 induces long-term depression (LTD) at synapses onto MSNs from both the cortex and the thalamus. Thalamostriatal LTD is selectively blocked by an mGlu2-selective negative allosteric modulator and reversed by application of an antagonist following LTD induction. Activation of mGlu2/3 also induces LTD of thalamostriatal transmission in striatal cholinergic interneurons (CINs), and pharmacological activation of mGlu2/3 or selective activation of mGlu2 inhibits CIN-mediated dopamine release evoked by selective stimulation of thalamostriatal inputs. Thus, mGlu2 activation exerts effects on striatal physiology that extend beyond modulation of corticostriatal synapses, and has the potential to influence cognition and striatum-related disorders via inhibition of thalamus-derived Glutamate and dopamine release.
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Metabotropic Glutamate Receptor 2 Positive Allosteric Modulators: Closing the Gate on Drug Abuse?
Biological psychiatry, 2015Co-Authors: Kari A Johnson, David M LovingerAbstract:Abnormally high levels of extracellular Glutamate, the principal excitatory neurotransmitter in the central nervous system, have been implicated in elevated drug seeking and taking as well as drug addiction (1). Presynaptic metabotropic Glutamate Receptors (mGluRs) can limit Glutamate release by acting as autoReceptors on Glutamatergic terminals (2). Among the eight subtypes of mGluRs, group II (mGluR2 and mGluR3) and group III (mGluR4, mGluR7, and mGluR8) are known to act as autoReceptors at excitatory synapses in the mammalian brain. Group II mGluRs have received considerable attention in recent years as contributing factors and therapeutic targets for drug abuse disorders (2). For example, several studies demonstrated that agonists of group II mGluRs decrease operant self-administration of drugs, including cocaine, alcohol, nicotine, and methamphetamine. In addition, activation of group II mGluRs attenuates cue-induced reinstatement of cocaine, heroin, alcohol, and methamphetamine self-administration as well as drug priming–induced reinstatement of nicotine, methamphetamine, and cocaine seeking. Conversely, an antagonist of group II mGluRs increases alcohol drinking (3). There is an evolving idea that presynaptic group II mGluRs may provide a “gatekeeper” function, limiting Glutamate release at key synapses in addiction circuitry.
Robert E. Marc - One of the best experts on this subject based on the ideXlab platform.
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Rapid Glutamate Receptor 2 trafficking during retinal degeneration
Molecular Neurodegeneration, 2012Co-Authors: Bryan W. Jones, Félix R Vazquéz-chona, J Scott Lauritzen, W Drew Ferrell, Robert E. MarcAbstract:Background Retinal degenerations, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP), are characterized by photoReceptor loss and anomalous remodeling of the surviving retina that corrupts visual processing and poses a barrier to late-stage therapeutic interventions in particular. However, the molecular events associated with retinal remodeling remain largely unknown. Given our prior evidence of ionotropic Glutamate Receptor (iGluR) reprogramming in retinal degenerations, we hypothesized that the edited Glutamate Receptor 2 (GluR2) subunit and its trafficking may be modulated in retinal degenerations. Results Adult albino Balb/C mice were exposed to intense light for 24 h to induce light-induced retinal degeneration (LIRD). We found that prior to the onset of photoReceptor loss, protein levels of GluR2 and related trafficking proteins, including Glutamate Receptor-interacting protein 1 (GRIP1) and postsynaptic density protein 95 (PSD-95), were rapidly increased. LIRD triggered neuritogenesis in photoReceptor survival regions, where GluR2 and its trafficking proteins were expressed in the anomalous dendrites. Immunoprecipitation analysis showed interaction between KIF3A and GRIP1 as well as PSD-95, suggesting that KIF3A may mediate transport of GluR2 and its trafficking proteins to the novel dendrites. However, in areas of photoReceptor loss, GluR2 along with its trafficking proteins nearly vanished in retracted retinal neurites. Conclusions All together, LIRD rapidly triggers GluR2 plasticity, which is a potential mechanism behind functionally phenotypic revisions of retinal neurons and neuritogenesis during retinal degenerations.
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Rapid Glutamate Receptor 2 trafficking during retinal degeneration.
Molecular neurodegeneration, 2012Co-Authors: Yanhua Lin, Félix R Vazquéz-chona, J Scott Lauritzen, W Drew Ferrell, Bryan W. Jones, Aihua Liu, Robert E. MarcAbstract:Background Retinal degenerations, such as age-related macular degeneration (AMD) and retinitis pigmentosa (RP), are characterized by photoReceptor loss and anomalous remodeling of the surviving retina that corrupts visual processing and poses a barrier to late-stage therapeutic interventions in particular. However, the molecular events associated with retinal remodeling remain largely unknown. Given our prior evidence of ionotropic Glutamate Receptor (iGluR) reprogramming in retinal degenerations, we hypothesized that the edited Glutamate Receptor 2 (GluR2) subunit and its trafficking may be modulated in retinal degenerations.
José María Cid - One of the best experts on this subject based on the ideXlab platform.
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Journal of Medicinal Chemistry - Covalent Allosteric Probe for the Metabotropic Glutamate Receptor 2: Design, Synthesis, and Pharmacological Characterization
Journal of medicinal chemistry, 2018Co-Authors: Maarten L.j. Doornbos, Andrés A. Trabanco, José María Cid, Hilde Lavreysen, Luc Peeters, Laura Pérez-benito, Laura H. Heitman, Xuesong Wang, Sophie C. Vermond, Gary TresadernAbstract:Covalent labeling of G protein-coupled Receptors (GPCRs) by small molecules is a powerful approach to understand binding modes, mechanism of action, pharmacology, and even facilitate structure elucidation. We report the first covalent positive allosteric modulator (PAM) for a class C GPCR, the mGlu2 Receptor. Three putatively covalent mGlu2 PAMs were designed and synthesized. Pharmacological characterization identified 2 to bind the Receptor covalently. Computational modeling combined with Receptor mutagenesis revealed T7917.29×30 as the likely position of covalent interaction. We show how this covalent ligand can be used to characterize the PAM binding mode and that it is a valuable tool compound in studying Receptor function and binding kinetics. Our findings advance the understanding of the mGlu2 PAM interaction and suggest that 2 is a valuable probe for further structural and chemical biology approaches.
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molecular mechanism of positive allosteric modulation of the metabotropic Glutamate Receptor 2 by jnj 46281222
British Journal of Pharmacology, 2016Co-Authors: Maarten L.j. Doornbos, Andrés A. Trabanco, José María Cid, Hilde Lavreysen, Gary Tresadern, Ilse Biesmans, Laura Perezbenito, Thea Mulderkrieger, Adriaan P. IjzermanAbstract:BACKGROUND AND PURPOSE Allosteric modulation of the mGlu2 Receptor is a potential strategy for treatment of various neurological and psychiatric disorders. Here, we describe the in vitro characterization of the mGlu2 positive allosteric modulator (PAM) JNJ-46281222 and its radiolabelled counterpart [(3) H]-JNJ-46281222. Using this novel tool, we also describe the allosteric effect of orthosteric Glutamate binding and the presence of a bound G protein on PAM binding and use computational approaches to further investigate the binding mode. EXPERIMENTAL APPROACH We have used radioligand binding studies, functional assays, site-directed mutagenesis, homology modelling and molecular dynamics to study the binding of JNJ-46281222. KEY RESULTS JNJ-46281222 is an mGlu2 -selective, highly potent PAM with nanomolar affinity (KD = 1.7 nM). Binding of [(3) H]-JNJ-46281222 was increased by the presence of Glutamate and greatly reduced by the presence of GTP, indicating the preference for a G protein bound state of the Receptor for PAM binding. Its allosteric binding site was visualized and analysed by a computational docking and molecular dynamics study. The simulations revealed amino acid movements in regions expected to be important for activation. The binding mode was supported by [(3) H]-JNJ-46281222 binding experiments on mutant Receptors. CONCLUSION AND IMPLICATIONS Our results obtained with JNJ-46281222 in unlabelled and tritiated form further contribute to our understanding of mGlu2 allosteric modulation. The computational simulations and mutagenesis provide a plausible binding mode with indications of how the ligand permits allosteric activation. This study is therefore of interest for mGlu2 and class C Receptor drug discovery.
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Molecular mechanism of positive allosteric modulation of the metabotropic Glutamate Receptor 2 by JNJ‐46281222
British journal of pharmacology, 2016Co-Authors: Maarten L.j. Doornbos, Andrés A. Trabanco, José María Cid, Hilde Lavreysen, Gary Tresadern, Laura Pérez-benito, Thea Mulder-krieger, Ilse Biesmans, Adriaan P. Ijzerman, Laura H. HeitmanAbstract:BACKGROUND AND PURPOSE Allosteric modulation of the mGlu2 Receptor is a potential strategy for treatment of various neurological and psychiatric disorders. Here, we describe the in vitro characterization of the mGlu2 positive allosteric modulator (PAM) JNJ-46281222 and its radiolabelled counterpart [(3) H]-JNJ-46281222. Using this novel tool, we also describe the allosteric effect of orthosteric Glutamate binding and the presence of a bound G protein on PAM binding and use computational approaches to further investigate the binding mode. EXPERIMENTAL APPROACH We have used radioligand binding studies, functional assays, site-directed mutagenesis, homology modelling and molecular dynamics to study the binding of JNJ-46281222. KEY RESULTS JNJ-46281222 is an mGlu2 -selective, highly potent PAM with nanomolar affinity (KD = 1.7 nM). Binding of [(3) H]-JNJ-46281222 was increased by the presence of Glutamate and greatly reduced by the presence of GTP, indicating the preference for a G protein bound state of the Receptor for PAM binding. Its allosteric binding site was visualized and analysed by a computational docking and molecular dynamics study. The simulations revealed amino acid movements in regions expected to be important for activation. The binding mode was supported by [(3) H]-JNJ-46281222 binding experiments on mutant Receptors. CONCLUSION AND IMPLICATIONS Our results obtained with JNJ-46281222 in unlabelled and tritiated form further contribute to our understanding of mGlu2 allosteric modulation. The computational simulations and mutagenesis provide a plausible binding mode with indications of how the ligand permits allosteric activation. This study is therefore of interest for mGlu2 and class C Receptor drug discovery.
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Molecular determinants of positive allosteric modulation of the human metabotropic Glutamate Receptor 2.
British journal of pharmacology, 2015Co-Authors: A Farinha, Andrés A. Trabanco, José María Cid, Hilde Lavreysen, Luc Peeters, B Russo, Stefan Masure, Gary TresadernAbstract:Background and Purpose The activation of the metabotropic Glutamate Receptor 2 (mGlu2) reduces Glutamatergic transmission in brain regions where excess excitatory signalling is implicated in disorders such as anxiety and schizophrenia. Positive allosteric modulators (PAMs) can provide a fine-tuned potentiation of these Receptors' function and are being investigated as a novel therapeutic approach. An extensive set of mutant human mGlu2 Receptors were used to investigate the molecular determinants that are important for positive allosteric modulation at this Receptor. Experimental Approach Site-directed mutagenesis, binding and functional assays were employed to identify amino acids important for the activity of nine PAMs. The data from the radioligand binding and mutagenesis studies were used with computational docking to predict a binding mode at an mGlu2 Receptor model based on the recent structure of the mGlu1 Receptor. Key Results New amino acids in TM3 (R635, L639, F643), TM5 (L732) and TM6 (W773, F776) were identified for the first time as playing an important role in the activity of mGlu2 PAMs. Conclusions and Implications This extensive study furthers our understanding of positive allosteric modulation of the mGlu2 Receptor and can contribute to improved future design of mGlu2 PAMs.
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Metabotropic Glutamate Receptor 2 Activators
Small Molecule Therapeutics for Schizophrenia, 2014Co-Authors: José María Cid, Andrés A. Trabanco, Hilde LavreysenAbstract:Schizophrenia is a common and severe, often disabling psychiatric illness of unknown aetiology that affects approximately 24 million people worldwide. The illness is characterized by symptomatology comprising positive symptoms (hallucinations and delusional behaviours), negative symptoms (anhedonia, social withdrawal and apathy) and cognitive dysfunction (diminished capacity for learning, memory and executive function). Current pharmacological treatments are effective at alleviating positive symptoms but have limited impact on negative symptoms and cognitive deficits. Furthermore, the extrapyramidal symptoms, hyperprolactinemia and metabolic syndrome, including substantial weight gain, are typical side effects limiting the value of many of these drugs for patients. Thus, drugs that better serve the patient population by effectively treating all symptoms with improved safety and tolerability remain a critical unmet need. Modulation of the metabotropic Glutamate type 2 (mGlu2) Receptor has emerged as a promising mechanism for the treatment of CNS diseases, with the potential to provide a new and more effective avenue for the treatment of schizophrenia.