51
|
Thalhammer A, Jaudon F, Cingolani LA. Emerging Roles of Activity-Dependent Alternative Splicing in Homeostatic Plasticity. Front Cell Neurosci 2020; 14:104. [PMID: 32477067 PMCID: PMC7235277 DOI: 10.3389/fncel.2020.00104] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Accepted: 04/06/2020] [Indexed: 12/25/2022] Open
Abstract
Homeostatic plasticity refers to the ability of neuronal networks to stabilize their activity in the face of external perturbations. Most forms of homeostatic plasticity ultimately depend on changes in the expression or activity of ion channels and synaptic proteins, which may occur at the gene, transcript, or protein level. The most extensively investigated homeostatic mechanisms entail adaptations in protein function or localization following activity-dependent posttranslational modifications. Numerous studies have also highlighted how homeostatic plasticity can be achieved by adjusting local protein translation at synapses or transcription of specific genes in the nucleus. In comparison, little attention has been devoted to whether and how alternative splicing (AS) of pre-mRNAs underlies some forms of homeostatic plasticity. AS not only expands proteome diversity but also contributes to the spatiotemporal dynamics of mRNA transcripts. Prominent in the brain where it can be regulated by neuronal activity, it is a flexible process, tightly controlled by a multitude of factors. Given its extensive use and versatility in optimizing the function of ion channels and synaptic proteins, we argue that AS is ideally suited to achieve homeostatic control of neuronal output. We support this thesis by reviewing emerging evidence linking AS to various forms of homeostatic plasticity: homeostatic intrinsic plasticity, synaptic scaling, and presynaptic homeostatic plasticity. Further, we highlight the relevance of this connection for brain pathologies.
Collapse
Affiliation(s)
- Agnes Thalhammer
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Fanny Jaudon
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| | - Lorenzo A Cingolani
- Center for Synaptic Neuroscience and Technology, Istituto Italiano di Tecnologia (IIT), Genoa, Italy.,Department of Life Sciences, University of Trieste, Trieste, Italy
| |
Collapse
|
52
|
Sanderson TM, Georgiou J, Collingridge GL. Illuminating Relationships Between the Pre- and Post-synapse. Front Neural Circuits 2020; 14:9. [PMID: 32308573 PMCID: PMC7146027 DOI: 10.3389/fncir.2020.00009] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 03/06/2020] [Indexed: 12/11/2022] Open
Abstract
Excitatory synapses in the mammalian cortex are highly diverse, both in terms of their structure and function. However, relationships between synaptic features indicate they are highly coordinated entities. Imaging techniques, that enable physiology at the resolution of individual synapses to be investigated, have allowed the presynaptic activity level of the synapse to be related to postsynaptic function. This approach has revealed that neuronal activity induces the pre- and post-synapse to be functionally correlated and that subsets of synapses are more susceptible to certain forms of synaptic plasticity. As presynaptic function is often examined in isolation from postsynaptic properties, the effect it has on the post-synapse is not fully understood. However, since postsynaptic receptors at excitatory synapses respond to release of glutamate, it follows that they may be differentially regulated depending on the frequency of its release. Therefore, examining postsynaptic properties in the context of presynaptic function may be a useful way to approach a broad range of questions on synaptic physiology. In this review, we focus on how optophysiology tools have been utilized to study relationships between the pre- and the post-synapse. Multiple imaging techniques have revealed correlations in synaptic properties from the submicron to the dendritic level. Optical tools together with advanced imaging techniques are ideally suited to illuminate this area further, due to the spatial resolution and control they allow.
Collapse
Affiliation(s)
| | - John Georgiou
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada
| | - Graham L Collingridge
- Lunenfeld-Tanenbaum Research Institute, Toronto, ON, Canada.,Tanz Centre for Research in Neurodegenerative Diseases, Department of Physiology, University of Toronto, Toronto, ON, Canada.,Glutamate Research Group, School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| |
Collapse
|
53
|
Pujol CN, Dupuy V, Séveno M, Runtz L, Bockaert J, Marin P, Chaumont-Dubel S. Dynamic interactions of the 5-HT 6 receptor with protein partners control dendritic tree morphogenesis. Sci Signal 2020; 13:13/618/eaax9520. [PMID: 32047117 DOI: 10.1126/scisignal.aax9520] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The serotonin (5-hydroxytrypatmine) receptor 5-HT6 (5-HT6R) has emerged as a promising target to alleviate the cognitive symptoms of neurodevelopmental diseases. We previously demonstrated that 5-HT6R finely controls key neurodevelopmental steps, including neuronal migration and the initiation of neurite growth, through its interaction with cyclin-dependent kinase 5 (Cdk5). Here, we showed that 5-HT6R recruited G protein-regulated inducer of neurite outgrowth 1 (GPRIN1) through a Gs-dependent mechanism. Interactions between the receptor and either Cdk5 or GPRIN1 occurred sequentially during neuronal differentiation. The 5-HT6R-GPRIN1 interaction enhanced agonist-independent, receptor-stimulated cAMP production without altering the agonist-dependent response in NG108-15 neuroblastoma cells. This interaction also promoted neurite extension and branching in NG108-15 cells and primary mouse striatal neurons through a cAMP-dependent protein kinase A (PKA)-dependent mechanism. This study highlights the complex allosteric modulation of GPCRs by protein partners and demonstrates how dynamic interactions between GPCRs and their protein partners can control the different steps of highly coordinated cellular processes, such as dendritic tree morphogenesis.
Collapse
Affiliation(s)
- Camille N Pujol
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Vincent Dupuy
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Martial Séveno
- BioCampus Montpellier, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Leonie Runtz
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.,Department of Psychiatry, McGill University, Douglas Hospital Research Center, Montreal, Canada
| | - Joël Bockaert
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France
| | - Philippe Marin
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.
| | - Séverine Chaumont-Dubel
- Institut de Génomique Fonctionnelle, Université de Montpellier, CNRS, INSERM, Montpellier, France.
| |
Collapse
|
54
|
Glutamatergic postsynaptic density in early life stress programming: Topographic gene expression of mGlu5 receptors and Homer proteins. Prog Neuropsychopharmacol Biol Psychiatry 2020; 96:109725. [PMID: 31404590 DOI: 10.1016/j.pnpbp.2019.109725] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 07/24/2019] [Accepted: 07/28/2019] [Indexed: 11/24/2022]
Abstract
Type-5 metabotropic glutamate receptors (mGlu5) have been implicated in the mechanism of resilience to stress. They form part of the postsynaptic density (PSD), a thickening of the glutamatergic synapse that acts as a multimodal hub for multiple cellular signaling. Perinatal stress in rats triggers alterations that make adult offspring less resilient to stress. In the present study, we examined the expression of gene encoding the mGlu5 (Grm5), as well as those encoding the short and long isoforms of Homer proteins in different brain regions of the offspring of dams exposed to repeated episodes of restraint stress during pregnancy ("perinatally stressed" or PRS offspring). To this end, we investigated unconditioned behavioral response using the light/dark box test, as well as the expression of PSD genes (Homer1a, Homer1b, and Grm5), in the medial prefrontal cortex, cortex, caudate-putamen, amygdala, and dorsal hippocampus. PRS rats spent significantly less time in the light area than the control group. In the amygdala, Homer1a mRNA levels were significantly increased in PRS rats, whereas Homer1b and Grm5 mRNA levels were reduced. In contrast, the transcript encoding for Homer1a was significantly reduced in the medial prefrontal cortex, caudate-putamen, and dorsal hippocampus of PRS rats. We also evaluated the relative ratio between Homer1a and Homer1b/Grm5 expression, finding a significant shift toward the expression of Homer1a in the amygdala and toward Homer1b/Grm5 in the other brain regions. These topographic patterns of Homer1a, Homer1b, and mGlu5 gene expression were significantly correlated with risk-taking behavior measured in the light/dark box test. Remarkably, in the amygdala and in other brain regions, Homer1b and Grm5 expression showed positive correlation with time spent in the light box, whereas Homer1a in the amygdala showed a negative correlation with risk-taking behavior, in contrast with all other brain regions analyzed, wherein these correlations were positive. These results suggest that perinatal stress programs the developmental expression of PSD molecules involved in mGlu5 signaling in discrete brain regions, with a predominant role for the amygdala.
Collapse
|
55
|
Bell OH, Copland DA, Ward A, Nicholson LB, Lange CAK, Chu CJ, Dick AD. Single Eye mRNA-Seq Reveals Normalisation of the Retinal Microglial Transcriptome Following Acute Inflammation. Front Immunol 2020; 10:3033. [PMID: 31993055 PMCID: PMC6964706 DOI: 10.3389/fimmu.2019.03033] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/10/2019] [Indexed: 01/07/2023] Open
Abstract
Background: Whether retinal microglia can maintain or restore immune homeostasis during and after inflammation is unclear. We performed single-eye mRNA-sequencing on microglia at different timepoints following a single inflammatory stimulus to characterise their transcriptome during and after resolution of endotoxin-induced uveitis (EIU). Experimental Approach: Cx3cr1 CreER :R26-tdTomato (C57BL/6) male heterozygotes were administered tamoxifen via different regimes at 4-5 weeks of age. Four weeks post-tamoxifen, mice were injected intravitreally with 10 ng lipopolysaccharide (endotoxin induced uveitis, EIU). Six-hundred retinal microglia were obtained by FACS from individual naïve retinas and at 4 h, 18 h, and 2 weeks following EIU induction. Samples were sequenced to a depth of up to 16.7 million reads using the SMART-Seq v4 Ultra Low Input RNA kit. The data was analysed using Partek software and Ingenuity Pathway Analysis. Genes were considered differentially-expressed (DEG) if the FDR step-up p-value was ≤0.05 and the fold-change was ≥±2. Results: Flow cytometric analysis indicates that the Cx3cr1 CreER :R26-tdTomato strain is both sensitive (>95% tagging) and specific (>95% specificity) for microglia when tamoxifen is administered topically to the eye for 3 days. During "early" activation, 613 DEGs were identified. In contrast, 537 DEGs were observed during peak cellular infiltrate and none at 2 weeks, compared to baseline controls (1,069 total unique DEGs). Key marker changes were validated by qPCR, flow cytometry, and fluorescence microscopy. C5AR1 was identified and validated as a robust marker of differentiating microglial subsets during an LPS response. Conclusion: Using EIU to provide a single defined inflammatory stimulus, mRNA-Seq identified acute transcriptional changes in retinal microglia which returned to their original transcriptome after 2 weeks. Yolk-sac derived microglia are capable of restoring their homeostatic state after acute inflammation.
Collapse
Affiliation(s)
- Oliver H Bell
- Academic Unit of Ophthalmology, Translational Health Sciences, University of Bristol, Bristol, United Kingdom
| | - David A Copland
- Academic Unit of Ophthalmology, Translational Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Amy Ward
- Academic Unit of Ophthalmology, Translational Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Lindsay B Nicholson
- Academic Unit of Ophthalmology, Translational Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Clemens A K Lange
- Eye Clinic, Medical Centre, University of Freiburg, Freiburg, Germany.,Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Colin J Chu
- Academic Unit of Ophthalmology, Translational Health Sciences, University of Bristol, Bristol, United Kingdom
| | - Andrew D Dick
- Academic Unit of Ophthalmology, Translational Health Sciences, University of Bristol, Bristol, United Kingdom.,Institute of Ophthalmology and the National Institute for Health Research Biomedical Research Centre, Moorfields Eye Hospital and University College London, London, United Kingdom
| |
Collapse
|
56
|
Translating preclinical findings in clinically relevant new antipsychotic targets: focus on the glutamatergic postsynaptic density. Implications for treatment resistant schizophrenia. Neurosci Biobehav Rev 2019; 107:795-827. [DOI: 10.1016/j.neubiorev.2019.08.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2019] [Revised: 07/20/2019] [Accepted: 08/22/2019] [Indexed: 02/07/2023]
|
57
|
Cingolani LA, Vitale C, Dityatev A. Intra- and Extracellular Pillars of a Unifying Framework for Homeostatic Plasticity: A Crosstalk Between Metabotropic Receptors and Extracellular Matrix. Front Cell Neurosci 2019; 13:513. [PMID: 31803023 PMCID: PMC6877475 DOI: 10.3389/fncel.2019.00513] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 10/29/2019] [Indexed: 11/18/2022] Open
Abstract
In the face of chronic changes in incoming sensory inputs, neuronal networks are capable of maintaining stable conditions of electrical activity over prolonged periods of time by adjusting synaptic strength, to amplify or dampen incoming inputs [homeostatic synaptic plasticity (HSP)], or by altering the intrinsic excitability of individual neurons [homeostatic intrinsic plasticity (HIP)]. Emerging evidence suggests a synergistic interplay between extracellular matrix (ECM) and metabotropic receptors in both forms of homeostatic plasticity. Activation of dopaminergic, serotonergic, or glutamate metabotropic receptors stimulates intracellular signaling through calmodulin-dependent protein kinase II, protein kinase A, protein kinase C, and inositol trisphosphate receptors, and induces changes in expression of ECM molecules and proteolysis of both ECM molecules (lecticans) and ECM receptors (NPR, CD44). The resulting remodeling of perisynaptic and synaptic ECM provides permissive conditions for HSP and plays an instructive role by recruiting additional signaling cascades, such as those through metabotropic glutamate receptors and integrins. The superimposition of all these signaling events determines intracellular and diffusional trafficking of ionotropic glutamate receptors, resulting in HSP and modulation of conditions for inducing Hebbian synaptic plasticity (i.e., metaplasticity). It also controls cell-surface delivery and activity of voltage- and Ca2+-gated ion channels, resulting in HIP. These mechanisms may modify epileptogenesis and become a target for therapeutic interventions.
Collapse
Affiliation(s)
- Lorenzo A. Cingolani
- Department of Life Sciences, University of Trieste, Trieste, Italy
- Center for Synaptic Neuroscience and Technology (NSYN), Istituto Italiano di Tecnologia, Genoa, Italy
| | - Carmela Vitale
- Center for Synaptic Neuroscience and Technology (NSYN), Istituto Italiano di Tecnologia, Genoa, Italy
- Department of Experimental Medicine, University of Genoa, Genoa, Italy
| | - Alexander Dityatev
- Molecular Neuroplasticity, German Center for Neurodegenerative Diseases (DZNE), Magdeburg, Germany
- Medical Faculty, Otto von Guericke University Magdeburg, Magdeburg, Germany
- Center for Behavioral Brain Sciences, Magdeburg, Germany
| |
Collapse
|
58
|
The 5-HT 6 receptor interactome: New insight in receptor signaling and its impact on brain physiology and pathologies. Neuropharmacology 2019; 172:107839. [PMID: 31682856 DOI: 10.1016/j.neuropharm.2019.107839] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 10/29/2019] [Accepted: 10/31/2019] [Indexed: 01/02/2023]
Abstract
The serotonin (5-HT)6 receptor is a Gs-coupled receptor exclusively expressed in the central nervous system. Highest receptor densities are found in brain regions implicated in mnemonic functions where the receptor is primarily but not exclusively located in the primary cilium of neurons. The 5-HT6 receptor continues to raise particular interest for neuropharmacologists, given the pro-cognitive effects of antagonists in a wide range of cognitive impairment paradigms in rodents and human. The 5-HT6 receptor also finely controls key neuro-developmental processes including neuron migration and differentiation. However, its influence upon neurodevelopment and cognition is not solely mediated by its coupling to the Gs-adenylyl cyclase pathway, suggesting alternative signal transduction mechanisms. This prompted studies aimed at characterizing the receptor interactome that identified 125 candidate receptor partners, making the 5-HT6 receptor one of the G protein-coupled receptors with the most extensively characterized interactome. These studies showed that the receptor localization at the plasma membrane and, consequently, its signal transduction, are finely modulated by several receptor partners. They demonstrated that prefrontal 5-HT6 receptors engage the mTOR pathway to compromise cognition in neurodevelopmental models of schizophrenia, and a role of the 5-HT6-mTOR pathway in temporal epilepsy. Finally, they revealed that the receptor activates Cdk5 signaling in an agonist-independent manner through a mechanism involving receptor phosphorylation by the associated Cdk5 and highlighted its key role in the migration of neurons and neurite growth. These new receptor-operated signaling mechanisms should be considered in the future development of drugs acting on 5-HT6 receptors. This article is part of the special issue entitled 'Serotonin Research: Crossing Scales and Boundaries'.
Collapse
|
59
|
Methylation determines the extracellular calcium sensitivity of the leak channel NALCN in hippocampal dentate granule cells. Exp Mol Med 2019; 51:1-14. [PMID: 31601786 PMCID: PMC6802672 DOI: 10.1038/s12276-019-0325-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 07/18/2019] [Accepted: 07/22/2019] [Indexed: 12/12/2022] Open
Abstract
The sodium leak channel NALCN is a key player in establishing the resting membrane potential (RMP) in neurons and transduces changes in extracellular Ca2+ concentration ([Ca2+]e) into increased neuronal excitability as the downstream effector of calcium-sensing receptor (CaSR). Gain-of-function mutations in the human NALCN gene cause encephalopathy and severe intellectual disability. Thus, understanding the regulatory mechanisms of NALCN is important for both basic and translational research. This study reveals a novel mechanism for NALCN regulation by arginine methylation. Hippocampal dentate granule cells in protein arginine methyltransferase 7 (PRMT7)-deficient mice display a depolarization of the RMP, decreased threshold currents, and increased excitability compared to wild-type neurons. Electrophysiological studies combined with molecular analysis indicate that enhanced NALCN activities contribute to hyperexcitability in PRMT7−/− neurons. PRMT7 depletion in HEK293T cells increases NALCN activity by shifting the dose-response curve of NALCN inhibition by [Ca2+]e without affecting NALCN protein levels. In vitro methylation studies show that PRMT7 methylates a highly conserved Arg1653 of the NALCN gene located in the carboxy-terminal region that is implicated in CaSR-mediated regulation. A kinase-specific phosphorylation site prediction program shows that the adjacent Ser1652 is a potential phosphorylation site. Consistently, our data from site-specific mutants and PKC inhibitors suggest that Arg1653 methylation might modulate Ser1652 phosphorylation mediated by CaSR/PKC-delta, leading to [Ca2+]e-mediated NALCN suppression. Collectively, these data suggest that PRMT7 deficiency decreases NALCN methylation at Arg1653, which, in turn, decreases CaSR/PKC-mediated Ser1652 phosphorylation, lifting NALCN inhibition, thereby enhancing neuronal excitability. Thus, PRMT7-mediated NALCN inhibition provides a potential target for the development of therapeutic tools for neurological diseases. The addition of a methyl group to an arginine residue on the ion channel NALCN contributes to suppress the activity of this membrane protein and reduces neuronal excitability. Hana Cho, Jong-Sun Kang and colleagues at Sungkyunkwan University in South Korea found that neurons in the hippocampus of mice lacking an enzyme that mediates the transfer of methyl groups to proteins have increased NALCN activity and are more likely to fire an electrical signal. Furthermore, they showed that NALCN methylation facilitates the phosphorylation of an adjacent amino acid that prevents channel activation in response to extracellular calcium concentrations. These findings suggest that NALCN methylation has a key role in regulating the channel’s sensitivity to calcium. Moreover, they reveal a new mechanism for regulating neuronal excitability that could be targeted therapeutically to ameliorate diseases characterised by neuronal hyperexcitability.
Collapse
|
60
|
Holz A, Mülsch F, Schwarz MK, Hollmann M, Döbrössy MD, Coenen VA, Bartos M, Normann C, Biber K, van Calker D, Serchov T. Enhanced mGlu5 Signaling in Excitatory Neurons Promotes Rapid Antidepressant Effects via AMPA Receptor Activation. Neuron 2019; 104:338-352.e7. [DOI: 10.1016/j.neuron.2019.07.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2018] [Revised: 05/14/2019] [Accepted: 07/12/2019] [Indexed: 12/14/2022]
|
61
|
Chokshi V, Gao M, Grier BD, Owens A, Wang H, Worley PF, Lee HK. Input-Specific Metaplasticity in the Visual Cortex Requires Homer1a-Mediated mGluR5 Signaling. Neuron 2019; 104:736-748.e6. [PMID: 31563294 DOI: 10.1016/j.neuron.2019.08.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 06/24/2019] [Accepted: 08/09/2019] [Indexed: 11/17/2022]
Abstract
Effective sensory processing depends on sensory experience-dependent metaplasticity, which allows homeostatic maintenance of neural network activity and preserves feature selectivity. Following a strong increase in sensory drive, plasticity mechanisms that decrease the strength of excitatory synapses are preferentially engaged to maintain stability in neural networks. Such adaptation has been demonstrated in various model systems, including mouse primary visual cortex (V1), where excitatory synapses on layer 2/3 (L2/3) neurons undergo rapid reduction in strength when visually deprived mice are reexposed to light. Here, we report that this form of plasticity is specific to intracortical inputs to V1 L2/3 neurons and depends on the activity of NMDA receptors (NMDARs) and group I metabotropic glutamate receptor 5 (mGluR5). Furthermore, we found that expression of the immediate early gene (IEG) Homer1a (H1a) and its subsequent interaction with mGluR5s are necessary for this input-specific metaplasticity.
Collapse
Affiliation(s)
- Varun Chokshi
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA; Cell Molecular Developmental Biology and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Ming Gao
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Bryce D Grier
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Ashley Owens
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Hui Wang
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Paul F Worley
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - Hey-Kyoung Lee
- The Zanvyl Krieger Mind/Brain Institute, Johns Hopkins University, Baltimore, MD 21218, USA; Cell Molecular Developmental Biology and Biophysics (CMDB) Graduate Program, Johns Hopkins University, Baltimore, MD 21218, USA; The Solomon H. Snyder Department of Neuroscience, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA; Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD 21218, USA.
| |
Collapse
|
62
|
León-Navarro DA, Albasanz JL, Martín M. Functional Cross-Talk between Adenosine and Metabotropic Glutamate Receptors. Curr Neuropharmacol 2019; 17:422-437. [PMID: 29663888 PMCID: PMC6520591 DOI: 10.2174/1570159x16666180416093717] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Revised: 03/19/2018] [Accepted: 04/13/2018] [Indexed: 12/14/2022] Open
Abstract
Abstract: G-protein coupled receptors are transmembrane proteins widely expressed in cells and their transduction pathways are mediated by controlling second messenger levels through different G-protein interactions. Many of these receptors have been described as involved in the physiopathology of neurodegenerative diseases and even considered as potential targets for the design of novel therapeutic strategies. Endogenous and synthetic allosteric and orthosteric selective ligands are able to modulate GPCRs at both gene and protein expression levels and can also modify their physiological function. GPCRs that coexist in the same cells can homo- and heteromerize, therefore, modulating their function. Adenosine receptors are GPCRs which stimulate or inhibit adenylyl cyclase activity through Gi/Gs protein and are involved in the control of neurotransmitter release as glutamate. In turn, metabotropic glutamate receptors are also GPCRs which inhibit adenylyl cyclase or stimulate phospholipase C activities through Gi or Gq proteins, respectively. In recent years, evidence of crosstalk mechanisms be-tween different GPCRs have been described. The aim of the present review was to summarize the described mechanisms of interaction and crosstalking between adenosine and metabotropic glutamate receptors, mainly of group I, in both in vitro and in vivo systems, and their possible use for the design of novel ligands for the treatment of neurodegenerative diseases.
Collapse
Affiliation(s)
- David Agustín León-Navarro
- Departamento de Quimica Inorganica, Organica y Bioquimica. CRIB, Universidad de Castilla-La Mancha, Spain.,Facultad de Ciencias y Tecnologías Químicas, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain
| | - José Luis Albasanz
- Departamento de Quimica Inorganica, Organica y Bioquimica. CRIB, Universidad de Castilla-La Mancha, Spain.,Facultad de Ciencias y Tecnologías Químicas, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain.,Facultad de Medicina de Ciudad Real, Camino Moledores s/n. 13071 Ciudad Real, Spain
| | - Mairena Martín
- Departamento de Quimica Inorganica, Organica y Bioquimica. CRIB, Universidad de Castilla-La Mancha, Spain.,Facultad de Ciencias y Tecnologías Químicas, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain.,Facultad de Medicina de Ciudad Real, Camino Moledores s/n. 13071 Ciudad Real, Spain
| |
Collapse
|
63
|
Reiner A, Levitz J. Glutamatergic Signaling in the Central Nervous System: Ionotropic and Metabotropic Receptors in Concert. Neuron 2019; 98:1080-1098. [PMID: 29953871 DOI: 10.1016/j.neuron.2018.05.018] [Citation(s) in RCA: 360] [Impact Index Per Article: 72.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 04/19/2018] [Accepted: 05/10/2018] [Indexed: 12/28/2022]
Abstract
Glutamate serves as both the mammalian brain's primary excitatory neurotransmitter and as a key neuromodulator to control synapse and circuit function over a wide range of spatial and temporal scales. This functional diversity is decoded by two receptor families: ionotropic glutamate receptors (iGluRs) and metabotropic glutamate receptors (mGluRs). The challenges posed by the complexity and physiological importance of each of these subtypes has limited our appreciation and understanding of how these receptors work in concert. In this review, by comparing both receptor families with a focus on their crosstalk, we argue for a more holistic understanding of neural glutamate signaling.
Collapse
Affiliation(s)
- Andreas Reiner
- Department of Biology and Biotechnology, Ruhr University Bochum, Bochum, Germany.
| | - Joshua Levitz
- Department of Biochemistry, Weill Cornell Medicine, New York, NY, USA.
| |
Collapse
|
64
|
Hajj M, De Vita T, Vol C, Renassia C, Bologna JC, Brabet I, Cazade M, Pastore M, Blahos J, Labesse G, Pin JP, Prézeau L. Nonclassical Ligand-Independent Regulation of Go Protein by an Orphan Class C G-Protein–Coupled Receptor. Mol Pharmacol 2019; 96:233-246. [DOI: 10.1124/mol.118.113019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 05/28/2019] [Indexed: 01/20/2023] Open
|
65
|
Clifton NE, Trent S, Thomas KL, Hall J. Regulation and Function of Activity-Dependent Homer in Synaptic Plasticity. MOLECULAR NEUROPSYCHIATRY 2019; 5:147-161. [PMID: 31312636 DOI: 10.1159/000500267] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2019] [Accepted: 04/09/2019] [Indexed: 12/22/2022]
Abstract
Alterations in synaptic signaling and plasticity occur during the refinement of neural circuits over the course of development and the adult processes of learning and memory. Synaptic plasticity requires the rearrangement of protein complexes in the postsynaptic density (PSD), trafficking of receptors and ion channels and the synthesis of new proteins. Activity-induced short Homer proteins, Homer1a and Ania-3, are recruited to active excitatory synapses, where they act as dominant negative regulators of constitutively expressed, longer Homer isoforms. The expression of Homer1a and Ania-3 initiates critical processes of PSD remodeling, the modulation of glutamate receptor-mediated functions, and the regulation of calcium signaling. Together, available data support the view that Homer1a and Ania-3 are responsible for the selective, transient destabilization of postsynaptic signaling complexes to facilitate plasticity of the excitatory synapse. The interruption of activity-dependent Homer proteins disrupts disease-relevant processes and leads to memory impairments, reflecting their likely contribution to neurological disorders.
Collapse
Affiliation(s)
- Nicholas E Clifton
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom.,MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom
| | - Simon Trent
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Kerrie L Thomas
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom.,School of Biosciences, Cardiff University, Cardiff, United Kingdom
| | - Jeremy Hall
- Neuroscience and Mental Health Research Institute, Cardiff University, Cardiff, United Kingdom.,MRC Centre for Neuropsychiatric Genetics and Genomics, Institute of Psychological Medicine and Clinical Neurosciences, Cardiff University, Cardiff, United Kingdom
| |
Collapse
|
66
|
Garcia C, Maurel-Ribes A, Nauze M, N'Guyen D, Martinez LO, Payrastre B, Sénard JM, Galés C, Pons V. Deciphering biased inverse agonism of cangrelor and ticagrelor at P2Y 12 receptor. Cell Mol Life Sci 2019; 76:561-576. [PMID: 30406277 PMCID: PMC11105710 DOI: 10.1007/s00018-018-2960-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 10/15/2018] [Accepted: 10/29/2018] [Indexed: 12/12/2022]
Abstract
P2Y12 receptor (P2Y12-R) is one of the major targets for drug inhibiting platelet aggregation in the treatment/prevention of arterial thrombosis. However, the clinical use of P2Y12-R antagonists faces some limitations, such as a delayed onset of action (clopidogrel) or adverse effect profile (ticagrelor, cangrelor), justifying the development of a new generation of P2Y12-R antagonists with a better clinical benefit-risk balance. Although the recent concept of biased agonism offers the possibility to alleviate undesirable adverse effects while preserving therapeutic outcomes, it has never been explored at P2Y12-R. For the first time, using highly sensitive BRET2-based probes, we accurately delineated biased ligand efficacy at P2Y12-R in living HEK293T cells on G protein activation and downstream effectors. We demonstrated that P2Y12-R displayed constitutive Gi/o-dependent signaling that is impaired by the R122C mutation, previously associated with a bleeding disorder. More importantly, we reported the biased inverse agonist efficacy of cangrelor and ticagrelor that could underlie their clinical efficacy. Our study points out that constitutive P2Y12-R signaling is a normal feature of the receptor that might be essential for platelets to respond faster to a vessel injury. From a therapeutic standpoint, our data suggest that the beneficial advantages of antiplatelet drugs might be more related to inverse agonism at P2Y12-R than to antagonism of ADP-mediated signaling. In the future, deciphering P2Y12-R constitutive activity should allow the discovery of more selective biased P2Y12-R blockers demonstrating therapeutic advantages over classical antiplatelet drugs by improving therapeutic outcomes and concomitantly relieving undesirable adverse effects.
Collapse
Affiliation(s)
- Cédric Garcia
- Laboratoire d'Hématologie, Centre Hospitalier Universitaire de Toulouse, 31000, Toulouse, France
| | - Agnès Maurel-Ribes
- Laboratoire d'Hématologie, Centre Hospitalier Universitaire de Toulouse, 31000, Toulouse, France
| | - Michel Nauze
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Du N'Guyen
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Laurent O Martinez
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Bernard Payrastre
- Laboratoire d'Hématologie, Centre Hospitalier Universitaire de Toulouse, 31000, Toulouse, France
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Jean-Michel Sénard
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
- Service de Pharmacologie Clinique, Centre Hospitalier Universitaire de Toulouse, Université de Toulouse, 31000, Toulouse, France
| | - Céline Galés
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France
| | - Véronique Pons
- INSERM U1048, Institut des Maladies Métaboliques et Cardiovasculaires, Université de Toulouse, 1 Avenue Jean Poulhès, BP 84225, 31432, Toulouse Cedex 04, France.
| |
Collapse
|
67
|
Mechanisms underlying prelimbic prefrontal cortex mGlu 3/mGlu 5-dependent plasticity and reversal learning deficits following acute stress. Neuropharmacology 2018; 144:19-28. [PMID: 30326237 DOI: 10.1016/j.neuropharm.2018.10.013] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2018] [Revised: 09/22/2018] [Accepted: 10/12/2018] [Indexed: 01/09/2023]
Abstract
Stress can precipitate or worsen symptoms of many psychiatric illnesses. Dysregulation of the prefrontal cortex (PFC) glutamate system may underlie these disruptions and restoring PFC glutamate signaling has emerged as a promising avenue for the treatment of stress disorders. Recently, we demonstrated that activation of metabotropic glutamate receptor subtype 3 (mGlu3) induces a postsynaptic form of long-term depression (LTD) that is dependent on the activity of another subtype, mGlu5. Stress exposure disrupted this plasticity, but the underlying signaling mechanisms and involvement in higher-order cognition have not yet been investigated. Acute stress was applied by 20-min restraint and early reversal learning was evaluated in an operant-based food-seeking task. We employed whole-cell patch-clamp recordings of layer 5 prelimbic (PL)-PFC pyramidal cells to examine mGlu3-LTD and several mechanistically distinct mGlu5-dependent functions. Acute stress impaired both mGlu3-LTD and early reversal learning. Interestingly, potentiating mGlu5 signaling with the mGlu5 positive allosteric modulator (PAM) VU0409551 rescued stress-induced deficits in both mGlu3-LTD and reversal learning. Other aspects of PL-PFC mGlu5 function were not disrupted following stress; however, signaling downstream of mGlu5-Homer interactions, phosphoinositide-3-kinase (PI3K), Akt, and glycogen synthase kinase 3β was implicated in these phenomena. These findings demonstrate that acute stress disrupts early reversal learning and PL-PFC-dependent synaptic plasticity and that potentiating mGlu5 function can restore these impairments. These findings provide a framework through which modulating coordinated mGlu3/mGlu5 signaling may confer benefits for the treatment of stress-related psychiatric disorders.
Collapse
|
68
|
Abstract
The trillions of synaptic connections within the human brain are shaped by experience and neuronal activity, both of which underlie synaptic plasticity and ultimately learning and memory. G protein-coupled receptors (GPCRs) play key roles in synaptic plasticity by strengthening or weakening synapses and/or shaping dendritic spines. While most studies of synaptic plasticity have focused on cell surface receptors and their downstream signaling partners, emerging data point to a critical new role for the very same receptors to signal from inside the cell. Intracellular receptors have been localized to the nucleus, endoplasmic reticulum, lysosome, and mitochondria. From these intracellular positions, such receptors may couple to different signaling systems, display unique desensitization patterns, and/or show distinct patterns of subcellular distribution. Intracellular GPCRs can be activated at the cell surface, endocytosed, and transported to an intracellular site or simply activated in situ by de novo ligand synthesis, diffusion of permeable ligands, or active transport of non-permeable ligands. Current findings reinforce the notion that intracellular GPCRs play a dynamic role in synaptic plasticity and learning and memory. As new intracellular GPCR roles are defined, the need to selectively tailor agonists and/or antagonists to both intracellular and cell surface receptors may lead to the development of more effective therapeutic tools.
Collapse
Affiliation(s)
- Yuh-Jiin I. Jong
- Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Steven K. Harmon
- Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Karen L. O’Malley
- Department of Neuroscience, Washington University School of Medicine, Saint Louis, MO 63110, USA
| |
Collapse
|
69
|
Berg KA, Clarke WP. Making Sense of Pharmacology: Inverse Agonism and Functional Selectivity. Int J Neuropsychopharmacol 2018; 21:962-977. [PMID: 30085126 PMCID: PMC6165953 DOI: 10.1093/ijnp/pyy071] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Accepted: 08/04/2018] [Indexed: 12/12/2022] Open
Abstract
Constitutive receptor activity/inverse agonism and functional selectivity/biased agonism are 2 concepts in contemporary pharmacology that have major implications for the use of drugs in medicine and research as well as for the processes of new drug development. Traditional receptor theory postulated that receptors in a population are quiescent unless activated by a ligand. Within this framework ligands could act as agonists with various degrees of intrinsic efficacy, or as antagonists with zero intrinsic efficacy. We now know that receptors can be active without an activating ligand and thus display "constitutive" activity. As a result, a new class of ligand was discovered that can reduce the constitutive activity of a receptor. These ligands produce the opposite effect of an agonist and are called inverse agonists. The second topic discussed is functional selectivity, also commonly referred to as biased agonism. Traditional receptor theory also posited that intrinsic efficacy is a single drug property independent of the system in which the drug acts. However, we now know that a drug, acting at a single receptor subtype, can have multiple intrinsic efficacies that differ depending on which of the multiple responses coupled to a receptor is measured. Thus, a drug can be simultaneously an agonist, an antagonist, and an inverse agonist acting at the same receptor. This means that drugs have an additional level of selectivity (signaling selectivity or "functional selectivity") beyond the traditional receptor selectivity. Both inverse agonism and functional selectivity need to be considered when drugs are used as medicines or as research tools.
Collapse
Affiliation(s)
- Kelly A Berg
- Department of Pharmacology, University of Texas Health, San Antonio, Texas
| | - William P Clarke
- Department of Pharmacology, University of Texas Health, San Antonio, Texas,Correspondence: William P. Clarke, PhD, Department of Pharmacology, Mail Stop 7764, UT Health at San Antonio, 7703 Floyd Curl Drive, San Antonio, TX 78229 ()
| |
Collapse
|
70
|
Shim HG, Jang SS, Kim SH, Hwang EM, Min JO, Kim HY, Kim YS, Ryu C, Chung G, Kim Y, Yoon BE, Kim SJ. TNF-α increases the intrinsic excitability of cerebellar Purkinje cells through elevating glutamate release in Bergmann Glia. Sci Rep 2018; 8:11589. [PMID: 30072733 PMCID: PMC6072779 DOI: 10.1038/s41598-018-29786-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 07/18/2018] [Indexed: 11/17/2022] Open
Abstract
For decades, the glial function has been highlighted not only as the ‘structural glue’, but also as an ‘active participant’ in neural circuits. Here, we suggest that tumor necrosis factor α (TNF-α), a key inflammatory cytokine, alters the neural activity of the cerebellar Purkinje cells (PCs) by facilitating gliotransmission in the juvenile male rat cerebellum. A bath application of TNF-α (100 ng/ml) in acute cerebellar slices elevates spiking activity of PCs with no alterations in the regularity of PC firings. Interestingly, the effect of TNF-α on the intrinsic excitability of PCs was abolished under a condition in which the type1 TNF receptor (TNFR1) in Bergmann glia (BG) was genetically suppressed by viral delivery of an adeno-associated virus (AAV) containing TNFR1-shRNA. In addition, we measured the concentration of glutamate derived from dissociated cerebellar cortical astrocyte cultures treated with TNF-α and observed a progressive increase of glutamate in a time-dependent manner. We hypothesised that TNF-α-induced elevation of glutamate from BGs enveloping the synaptic cleft may directly activate metabotropic glutamate receptor1 (mGluR1). Pharmacological inhibition of mGluR1, indeed, prevented the TNF-α-mediated elevation of the intrinsic excitability in PCs. Taken together, our study reveals that TNF-α triggers glutamate release in BG, thereby increasing the intrinsic excitability of cerebellar PCs in a mGluR1-dependent manner.
Collapse
Affiliation(s)
- Hyun Geun Shim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea
| | - Sung-Soo Jang
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Seung Ha Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology, Seoul, Korea
| | - Joo Ok Min
- Department of Molecular biology, Dankook University, Chungnam, Korea
| | - Hye Yun Kim
- Department of Pharmacy and Integrated Science and Engineering Division, Yonsei University, Incheon, Korea
| | - Yoo Sung Kim
- Department of Molecular biology, Dankook University, Chungnam, Korea
| | - Changhyeon Ryu
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea.,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Geehoon Chung
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea.,Department of Brain and Cognitive Science, College of Science, Seoul National University, Seoul, Korea
| | - YoungSoo Kim
- Department of Pharmacy and Integrated Science and Engineering Division, Yonsei University, Incheon, Korea
| | - Bo-Eun Yoon
- Department of Molecular biology, Dankook University, Chungnam, Korea
| | - Sang Jeong Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea. .,Department of Biomedical Science, Seoul National University College of Medicine, Seoul, Korea. .,Neuroscience Research Institute, Seoul National University College of Medicine, Seoul, Korea.
| |
Collapse
|
71
|
Stefanik MT, Milovanovic M, Werner CT, Spainhour JCG, Wolf ME. Withdrawal From Cocaine Self-administration Alters the Regulation of Protein Translation in the Nucleus Accumbens. Biol Psychiatry 2018; 84:223-232. [PMID: 29622268 PMCID: PMC6054574 DOI: 10.1016/j.biopsych.2018.02.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 01/26/2018] [Accepted: 02/12/2018] [Indexed: 10/18/2022]
Abstract
BACKGROUND Cue-induced cocaine craving incubates during abstinence from cocaine self-administration. Expression of incubation ultimately depends on elevation of homomeric GluA1 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors in the nucleus accumbens (NAc). This adaptation requires ongoing protein translation for its maintenance. Aberrant translation is implicated in central nervous system diseases, but nothing is known about glutamatergic regulation of translation in the drug-naïve NAc or after incubation. METHODS NAc tissue was obtained from drug-naïve rats and from rats after 1 or >40 days of abstinence from extended-access cocaine or saline self-administration. Newly translated proteins were labeled using 35S-Met/Cys or puromycin. We compared basal overall translation and its regulation by metabotropic glutamate receptor 1 (mGlu1), mGlu5, and N-methyl-D-aspartate receptors (NMDARs) in drug-naïve, saline control, and cocaine rats, and we compared GluA1 and GluA2 translation by immunoprecipitating puromycin-labeled proteins. RESULTS In all groups, overall translation was unaltered by mGlu1 blockade (LY367385) but increased by mGlu5 blockade (MTEP). NMDAR blockade (AVP) increased overall translation in drug-naïve and saline control rats but not in cocaine/late withdrawal rats. Cocaine/late withdrawal rats exhibited greater translation of GluA1 (but not GluA2), which was not further affected by NMDAR blockade. CONCLUSIONS Our results suggest that increased GluA1 translation contributes to the elevated homomeric GluA1 alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor levels in the NAc that mediate incubation. Additional contributions to incubation-related plasticity may result from loss of the braking influence on translation normally exerted by NMDARs. Apart from elucidating incubation-related adaptations, we found a suppressive effect of mGlu5 on NAc translation regardless of drug exposure, which is opposite to results obtained in the hippocampus and points to heterogeneity of translational regulation between brain regions.
Collapse
Affiliation(s)
- Michael T Stefanik
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin School of Medicine and Science, North Chicago, Illinois
| | - Mike Milovanovic
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin School of Medicine and Science, North Chicago, Illinois
| | - Craig T Werner
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin School of Medicine and Science, North Chicago, Illinois
| | - John C G Spainhour
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Tech College of Engineering and Emory School of Medicine, Atlanta, Georgia
| | - Marina E Wolf
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin School of Medicine and Science, North Chicago, Illinois.
| |
Collapse
|
72
|
Stefanik MT, Sakas C, Lee D, Wolf ME. Ionotropic and metabotropic glutamate receptors regulate protein translation in co-cultured nucleus accumbens and prefrontal cortex neurons. Neuropharmacology 2018; 140:62-75. [PMID: 30077883 DOI: 10.1016/j.neuropharm.2018.05.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Revised: 05/15/2018] [Accepted: 05/29/2018] [Indexed: 01/14/2023]
Abstract
The regulation of protein translation by glutamate receptors and its role in plasticity have been extensively studied in the hippocampus. In contrast, very little is known about glutamatergic regulation of translation in nucleus accumbens (NAc) medium spiny neurons (MSN), despite their critical role in addiction-related plasticity and recent evidence that protein translation contributes to this plasticity. We used a co-culture system, containing NAc MSNs and prefrontal cortex (PFC) neurons, and fluorescent non-canonical amino acid tagging (FUNCAT) to visualize newly synthesized proteins in neuronal processes of NAc MSNs and PFC pyramidal neurons. First, we verified that the FUNCAT signal reflects new protein translation. Next, we examined the regulation of translation by group I metabotropic glutamate receptors (mGluRs) and ionotropic glutamate receptors by incubating co-cultures with agonists or antagonists during the 2-h period of non-canonical amino acid labeling. In NAc MSNs, basal translation was modestly reduced by blocking Ca2+-permeable AMPARs whereas blocking all AMPARs or suppressing constitutive mGluR5 signaling enhanced translation. Activating group I mGluRs with dihydroxyphenylglycine increased translation in an mGluR1-dependent manner in NAc MSNs and PFC pyramidal neurons. Disinhibiting excitatory transmission with bicuculline also increased translation. In MSNs, this was reversed by antagonists of mGluR1, mGluR5, AMPARs or NMDARs. In PFC neurons, AMPAR or NMDAR antagonists blocked bicuculline-stimulated translation. Our study, the first to examine glutamatergic regulation of translation in MSNs, demonstrates regulatory mechanisms specific to MSNs that depend on the level of neuronal activation. This sets the stage for understanding how translation may be altered in addiction.
Collapse
Affiliation(s)
- Michael T Stefanik
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA
| | - Courtney Sakas
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA
| | - Dennis Lee
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA
| | - Marina E Wolf
- Department of Neuroscience, The Chicago Medical School at Rosalind Franklin University of Medicine and Science, North Chicago, IL, 60064, USA.
| |
Collapse
|
73
|
Recent insights into antidepressant therapy: Distinct pathways and potential common mechanisms in the treatment of depressive syndromes. Neurosci Biobehav Rev 2018; 88:63-72. [DOI: 10.1016/j.neubiorev.2018.03.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 02/07/2018] [Accepted: 03/13/2018] [Indexed: 12/13/2022]
|
74
|
Suh YH, Chang K, Roche KW. Metabotropic glutamate receptor trafficking. Mol Cell Neurosci 2018; 91:10-24. [PMID: 29604330 DOI: 10.1016/j.mcn.2018.03.014] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Revised: 03/07/2018] [Accepted: 03/26/2018] [Indexed: 01/14/2023] Open
Abstract
The metabotropic glutamate receptors (mGlu receptors) are G protein-coupled receptors that bind to the excitatory neurotransmitter glutamate and are important in the modulation of neuronal excitability, synaptic transmission, and plasticity in the central nervous system. Trafficking of mGlu receptors in and out of the synaptic plasma membrane is a fundamental mechanism modulating excitatory synaptic function through regulation of receptor abundance, desensitization, and signaling profiles. In this review, we cover the regulatory mechanisms determining surface expression and endocytosis of mGlu receptors, with particular focus on post-translational modifications and receptor-protein interactions. The literature we review broadens our insight into the precise events defining the expression of functional mGlu receptors at synapses, and will likely contribute to the successful development of novel therapeutic targets for a variety of developmental, neurological, and psychiatric disorders.
Collapse
Affiliation(s)
- Young Ho Suh
- Department of Biomedical Sciences, Neuroscience Research Institute, Seoul National University College of Medicine, Seoul 03080, South Korea.
| | - Kai Chang
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
| | - Katherine W Roche
- Receptor Biology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
75
|
Nieto-Alamilla G, Escamilla-Sánchez J, López-Méndez MC, Molina-Hernández A, Guerrero-Hernández A, Arias-Montaño JA. Differential expression and signaling of the human histamine H 3 receptor isoforms of 445 and 365 amino acids expressed in human neuroblastoma SH-SY5Y cells. J Recept Signal Transduct Res 2018; 38:141-150. [PMID: 29557708 DOI: 10.1080/10799893.2018.1448995] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In stably-transfected human neuroblastoma SH-SY5Y cells, we have compared the effect of activating two isoforms of 445 and 365 amino acids of the human histamine H3 receptor (hH3R445 and hH3R365) on [35S]-GTPγS binding, forskolin-induced cAMP formation, depolarization-induced increase in the intracellular concentration of Ca2+ ions ([Ca2+]i) and depolarization-evoked [3 H]-dopamine release. Maximal specific binding (Bmax) of [3 H]-N-methyl-histamine to cell membranes was 953 ± 204 and 555 ± 140 fmol/mg protein for SH-SY5Y-hH3R445 and SH-SY5Y-hH3R365 cells, respectively, with similar dissociation constants (Kd, 0.86 nM and 0.81 nM). The mRNA of the hH3R365 isoform was 40.9 ± 7.9% of the hH3R445 isoform. No differences in receptor affinity were found for the H3R ligands histamine, immepip, (R)(-)-α-methylhistamine (RAMH), A-331440, clobenpropit and ciproxifan. Both the stimulation of [35S]-GTPγS binding and the inhibition of forskolin-stimulated cAMP accumulation by the agonist RAMH were significantly larger in SH-SY5Y-hH3R445 cells ([35S]-GTPγS binding, 158.1 ± 7.5% versus 136.5 ± 3.6% for SH-SY5Y-hH3R365 cells; cAMP accumulation, -74.0 ± 4.9% versus -43.5 ± 5.3%), with no significant effect on agonist potency. In contrast, there were no differences in the efficacy and potency of RAMH to inhibit [3 H]-dopamine release evoked by 100 mM K+ (-18.9 ± 3.0% and -20.5 ± 3.3%, for SH-SY5Y-hH3R445 and SH-SY5Y-hH3R365 cells), or the inhibition of depolarization-induced increase in [Ca2+]i (S2/S1 ratios: parental cells 0.967 ± 0.069, SH-SY5Y-hH3R445 cells 0.639 ± 0.049, SH-SY5Y-hH3R365 cells 0.737 ± 0.045). These results indicate that in SH-SY5Y cells, hH3R445 and hH3R365 isoforms regulate in a differential manner the signaling pathways triggered by receptor activation.
Collapse
Affiliation(s)
- Gustavo Nieto-Alamilla
- a Departamento de Fisiología, Biofísica y Neurociencias , Centro de Investigación y de Estudios Avanzados del IPN , Ciudad de México , México
| | - Juan Escamilla-Sánchez
- a Departamento de Fisiología, Biofísica y Neurociencias , Centro de Investigación y de Estudios Avanzados del IPN , Ciudad de México , México
| | - María-Cristina López-Méndez
- b Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN , Ciudad de México , México
| | - Anayansi Molina-Hernández
- c Departamento de Biología Celular , Instituto Nacional de Perinatología Isidro Espinosa de los Reyes , Ciudad de México , México
| | - Agustín Guerrero-Hernández
- b Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN , Ciudad de México , México
| | - José-Antonio Arias-Montaño
- a Departamento de Fisiología, Biofísica y Neurociencias , Centro de Investigación y de Estudios Avanzados del IPN , Ciudad de México , México
| |
Collapse
|
76
|
Nardecchia F, Orlando R, Iacovelli L, Colamartino M, Fiori E, Leuzzi V, Piccinin S, Nistico R, Puglisi-Allegra S, Di Menna L, Battaglia G, Nicoletti F, Pascucci T. Targeting mGlu5 Metabotropic Glutamate Receptors in the Treatment of Cognitive Dysfunction in a Mouse Model of Phenylketonuria. Front Neurosci 2018; 12:154. [PMID: 29615849 PMCID: PMC5864888 DOI: 10.3389/fnins.2018.00154] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 02/26/2018] [Indexed: 11/23/2022] Open
Abstract
We studied group-I metabotropic glutamate (mGlu) receptors in Pahenu2 (ENU2) mice, which mimic the genetics and neurobiology of human phenylketonuria (PKU), a metabolic disorder characterized, if untreated, by autism, and intellectual disability (ID). Male ENU2 mice showed increased mGlu5 receptor protein levels in the hippocampus and corpus striatum (but not in the prefrontal cortex) whereas the transcript of the mGlu5 receptor was unchanged. No changes in mGlu1 receptor mRNA and protein levels were found in any of the three brain regions of ENU2 mice. We extended the analysis to Homer proteins, which act as scaffolds by linking mGlu1 and mGlu5 receptors to effector proteins. Expression of the long isoforms of Homer was significantly reduced in the hippocampus of ENU2 mice, whereas levels of the short Homer isoform (Homer 1a) were unchanged. mGlu5 receptors were less associated to immunoprecipitated Homer in the hippocampus of ENU2 mice. The lack of mGlu5 receptor-mediated long-term depression (LTD) in wild-type mice (of BTBR strain) precluded the analysis of hippocampal synaptic plasticity in ENU2 mice. We therefore performed a behavioral analysis to examine whether pharmacological blockade of mGlu5 receptors could correct behavioral abnormalities in ENU2 mice. Using the same apparatus we sequentially assessed locomotor activity, object exploration, and spatial object recognition (spatial novelty test) after displacing some of the objects from their original position in the arena. Systemic treatment with the mGlu5 receptor antagonist, MPEP (20 mg/kg, i.p.), had a striking effect in the spatial novelty test by substantially increasing the time spent in exploring the displaced objects in ENU2 mice (but not in wild-type mice). These suggest a role for mGlu5 receptors in the pathophysiology of ID in PKU and suggest that, also in adult untreated animals, cognitive dysfunction may be improved by targeting these receptors with an appropriate therapy.
Collapse
Affiliation(s)
- Francesca Nardecchia
- Department of Physiology and Pharmacology, Sapienza Università di Roma, Rome, Italy.,Department of Pediatrics and Child Neuropsychiatry, Sapienza Università di Roma, Rome, Italy
| | - Rosamaria Orlando
- Department of Physiology and Pharmacology, Sapienza Università di Roma, Rome, Italy
| | - Luisa Iacovelli
- Department of Physiology and Pharmacology, Sapienza Università di Roma, Rome, Italy
| | - Marco Colamartino
- Daniel Bovet Department of Psychology, Neurobiology Research Center, Sapienza Università di Roma, Rome, Italy
| | - Elena Fiori
- Daniel Bovet Department of Psychology, Neurobiology Research Center, Sapienza Università di Roma, Rome, Italy
| | - Vincenzo Leuzzi
- Department of Pediatrics and Child Neuropsychiatry, Sapienza Università di Roma, Rome, Italy
| | - Sonia Piccinin
- Department of Physiology and Pharmacology, Sapienza Università di Roma, Rome, Italy.,Department of Biology, Università degli Studi di Roma Tor Vergata, Rome, Italy
| | - Robert Nistico
- Department of Biology, Università degli Studi di Roma Tor Vergata, Rome, Italy
| | - Stefano Puglisi-Allegra
- Daniel Bovet Department of Psychology, Neurobiology Research Center, Sapienza Università di Roma, Rome, Italy.,IRCCS Foundation Santa Lucia, Rome, Italy
| | | | | | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, Sapienza Università di Roma, Rome, Italy.,IRCCS Neuromed, Pozzilli, Italy
| | - Tiziana Pascucci
- Daniel Bovet Department of Psychology, Neurobiology Research Center, Sapienza Università di Roma, Rome, Italy.,IRCCS Foundation Santa Lucia, Rome, Italy
| |
Collapse
|
77
|
Sustained Activity of Metabotropic Glutamate Receptor: Homer, Arrestin, and Beyond. Neural Plast 2017; 2017:5125624. [PMID: 29359050 PMCID: PMC5735635 DOI: 10.1155/2017/5125624] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 10/10/2017] [Accepted: 10/31/2017] [Indexed: 01/08/2023] Open
Abstract
When activated, metabotropic glutamate receptors (mGlus) exert long-lasting changes within the glutamatergic synapses. One mechanism is a tonic effect of downstream signal transduction pathways via sustained activation of mGlu itself. Like many other G protein-coupled receptors (GPCRs), mGlu can exist in a constitutively active state, which persists agonist independently. In this paper, we review the current knowledge of the mechanisms underlying the constitutive activity of group I mGlus. The issues concerning Homer1a mechanism in the constitutive activity of group I mGlus and recent findings regarding the significant role of β-arrestin in sustained GPCR activity are also discussed. We propose that once in a state of sustained activation, the mGlu persistently activates downstream signaling pathways, including various adaptor proteins and kinases, such as β-arrestin and mitogen-activated protein kinases. In turn, these effector molecules bind to or phosphorylate the mGlu C-terminal binding domains and consequently regulate the activation state of the mGlu.
Collapse
|
78
|
Datko MC, Hu JH, Williams M, Reyes CM, Lominac KD, von Jonquieres G, Klugmann M, Worley PF, Szumlinski KK. Behavioral and Neurochemical Phenotyping of Mice Incapable of Homer1a Induction. Front Behav Neurosci 2017; 11:208. [PMID: 29163080 PMCID: PMC5672496 DOI: 10.3389/fnbeh.2017.00208] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 10/12/2017] [Indexed: 11/18/2022] Open
Abstract
Immediate early and constitutively expressed products of the Homer1 gene regulate the functional assembly of post-synaptic density proteins at glutamatergic synapses to influence excitatory neurotransmission and synaptic plasticity. Earlier studies of Homer1 gene knock-out (KO) mice indicated active, but distinct, roles for IEG and constitutively expressed Homer1 gene products in regulating cognitive, emotional, motivational and sensorimotor processing, as well as behavioral and neurochemical sensitivity to cocaine. More recent characterization of transgenic mice engineered to prevent generation of the IEG form (a.k.a Homer1a KO) pose a critical role for Homer1a in cocaine-induced behavioral and neurochemical sensitization of relevance to drug addiction and related neuropsychiatric disorders. Here, we extend our characterization of the Homer1a KO mouse and report a modest pro-depressant phenotype, but no deleterious effects of the KO upon spatial learning/memory, prepulse inhibition, or cocaine-induced place-conditioning. As we reported previously, Homer1a KO mice did not develop cocaine-induced behavioral or neurochemical sensitization within the nucleus accumbens; however, virus-mediated Homer1a over-expression within the nucleus accumbens reversed the sensitization phenotype of KO mice. We also report several neurochemical abnormalities within the nucleus accumbens of Homer1a KO mice that include: elevated basal dopamine and reduced basal glutamate content, Group1 mGluR agonist-induced glutamate release and high K+-stimulated release of dopamine and glutamate within this region. Many of the neurochemical anomalies exhibited by Homer1a KO mice are recapitulated upon deletion of the entire Homer1 gene; however, Homer1 deletion did not affect NAC dopamine or alter K+-stimulated neurotransmitter release within this region. These data show that the selective deletion of Homer1a produces a behavioral and neurochemical phenotype that is distinguishable from that produced by deletion of the entire Homer1 gene. Moreover, the data indicate a specific role for Homer1a in regulating cocaine-induced behavioral and neurochemical sensitization of potential relevance to the psychotogenic properties of this drug.
Collapse
Affiliation(s)
- Michael C Datko
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Jia-Hua Hu
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Melanie Williams
- Department of Molecular, Developmental and Cell Biology, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Cindy M Reyes
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Kevin D Lominac
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States
| | - Georg von Jonquieres
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Matthias Klugmann
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Paul F Worley
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Karen K Szumlinski
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, Santa Barbara, CA, United States.,Department of Molecular, Developmental and Cell Biology, University of California, Santa Barbara, Santa Barbara, CA, United States.,Neuroscience Research Institute, University of California, Santa Barbara, Santa Barbara, CA, United States
| |
Collapse
|
79
|
Jong YJI, Harmon SK, O'Malley KL. GPCR signalling from within the cell. Br J Pharmacol 2017; 175:4026-4035. [PMID: 28872669 DOI: 10.1111/bph.14023] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Revised: 08/08/2017] [Accepted: 08/17/2017] [Indexed: 12/22/2022] Open
Abstract
Traditionally, signal transduction from GPCRs is thought to emanate from the cell surface where receptor interactions with external stimuli can be transformed into a broad range of cellular responses. However, emergent data show that numerous GPCRs are also associated with various intracellular membranes where they may couple to different signalling systems, display unique desensitization patterns and/or exhibit distinct patterns of subcellular distribution. Although many GPCRs can be activated at the cell surface and subsequently endocytosed and transported to a unique intracellular site, other intracellular GPCRs can be activated in situ either via de novo ligand synthesis, diffusion of permeable ligands or active transport of nonpermeable ligands. Current findings reinforce the notion that intracellular GPCRs play a dynamic role in various biological functions including learning and memory, contractility and angiogenesis. As new intracellular GPCR roles are defined, the need to selectively tailor agonists and/or antagonists to both intracellular and cell surface receptors may lead to the development of more effective therapeutic tools. LINKED ARTICLES This article is part of a themed section on Molecular Pharmacology of GPCRs. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v175.21/issuetoc.
Collapse
Affiliation(s)
- Yuh-Jiin I Jong
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| | - Steven K Harmon
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| | - Karen L O'Malley
- Department of Neuroscience, Washington University School of Medicine, St. Louis, MO, USA
| |
Collapse
|
80
|
mGluR1 and mGluR5 Synergistically Control Cholinergic Synaptic Transmission in the Thalamic Reticular Nucleus. J Neurosci 2017; 36:7886-96. [PMID: 27466334 DOI: 10.1523/jneurosci.0409-16.2016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Accepted: 06/08/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Acetylcholine (ACh) signaling is involved in a wide range of processes, including arousal, attention, and learning. An increasing number of studies indicate that cholinergic control of these functions is highly deterministic, mediated by synaptic afferents that generate reliable and precise responses in postsynaptic neurons. However, mechanisms that govern plastic changes of cholinergic synaptic strength are poorly understood, even though they are likely critical in shaping the impact of cholinergic inputs on neuronal networks. We have recently shown that in the thalamic reticular nucleus (TRN), synaptic release of ACh generates excitatory-inhibitory biphasic postsynaptic responses, mediated by the activation of α4β2 nicotinic (nAChRs) and M2 muscarinic receptors (mAChRs), respectively. Here, using voltage-clamp recordings from TRN neurons in thalamocortical slices of mice, we demonstrate that the activation of Group I metabotropic glutamate receptors (mGluRs) by ambient or synaptically released glutamate evokes transient increases of nicotinic EPSCs. Additionally, we find that the selective Group I mGluR agonist DHPG [(S)-3,5-dihydroxyphenylglycine] evokes long-term potentiation of nicotinic EPSCs (mGluR-nLTP), dependent on increases in postsynaptic Ca(2+) concentration and the activation of phospholipase C. Both the induction and the maintenance of mGluR-nLTP require synergistic activation of mGluR1 and mGluR5. Together, our results show that postsynaptic Group I mGluRs are critically involved in the regulation of cholinergic synaptic strength on different time scales, suggesting that cholinergic control of local thalamic circuits is highly context-dependent and regulated by the overall levels of glutamatergic afferent activity. SIGNIFICANCE STATEMENT Cholinergic signaling controls information processing and plasticity in neuronal circuits, but the mechanisms underlying the regulation of cholinergic synaptic strength on different time scales are unknown. Here we identify mGluR1 and mGluR5 as key elements in the dynamic regulation of cholinergic synaptic inputs onto neurons of the TRN. Our findings highlight potential mechanisms that regulate cholinergic signaling in the mammalian brain.
Collapse
|
81
|
Buonaguro EF, Iasevoli F, Marmo F, Eramo A, Latte G, Avagliano C, Tomasetti C, de Bartolomeis A. Re-arrangements of gene transcripts at glutamatergic synapses after prolonged treatments with antipsychotics: A putative link with synaptic remodeling. Prog Neuropsychopharmacol Biol Psychiatry 2017; 76:29-41. [PMID: 28235555 DOI: 10.1016/j.pnpbp.2017.02.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Revised: 02/13/2017] [Accepted: 02/16/2017] [Indexed: 10/20/2022]
Abstract
OBJECTIVES The postsynaptic density (PSD) represents a site of dopamine-glutamate integration. Despite multiple evidence of PSD involvement in antipsychotic-induced synaptic changes, there are no direct head-to-head comparisons of the effects at the PSD of antipsychotics with different receptor profile and at different doses after chronic administration. METHODS Molecular imaging of gene expression was used to investigate whether chronic treatment with first and second generation antipsychotics (haloperidol, asenapine and olanzapine) may induce changes in the expression levels of PSD transcripts involved in schizophrenia pathophysiology, i.e. Homers, Shank1, PSD-95 and Arc. RESULTS Genes' expression patterns were differentially modulated after chronic administration of typical and atypical antipsychotics as well as by the same compound administered at different doses. Antipsychotic treatment reduced gene expression in cortical regions, while Homer1a was still induced in striatum by haloperidol even after prolonged treatment. Moreover, chronic treatments appeared to cause a "de-recruitment" of brain regions demonstrated to be activated in acute treatments, with a prominent effect in the cortex rather than in striatum. CONCLUSIONS These results let hypothesize that prolonged antipsychotic treatment may trigger a set of plastic changes involving scaffolding and effector molecules causing a possible re-arrangement of PSD transcripts in brain regions relevant to schizophrenia pathophysiology.
Collapse
Affiliation(s)
- Elisabetta Filomena Buonaguro
- Laboratory of Molecular and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, University of Naples Federico II, Italy
| | - Felice Iasevoli
- Laboratory of Molecular and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, University of Naples Federico II, Italy
| | - Federica Marmo
- Laboratory of Molecular and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, University of Naples Federico II, Italy
| | | | - Gianmarco Latte
- Laboratory of Molecular and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, University of Naples Federico II, Italy
| | - Camilla Avagliano
- Laboratory of Molecular and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, University of Naples Federico II, Italy
| | - Carmine Tomasetti
- Laboratory of Molecular and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, University of Naples Federico II, Italy
| | - Andrea de Bartolomeis
- Laboratory of Molecular and Translational Psychiatry, Unit of Treatment Resistant Psychosis, Section of Psychiatry, University of Naples Federico II, Italy.
| |
Collapse
|
82
|
Luo X, Shui Y, Wang F, Yamamoto R, Kato N. Impaired retention of depression-like behavior in a mouse model of Alzheimer's disease. IBRO Rep 2017; 2:81-86. [PMID: 30135936 PMCID: PMC6084821 DOI: 10.1016/j.ibror.2017.05.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/01/2017] [Accepted: 05/01/2017] [Indexed: 01/07/2023] Open
Abstract
By using a 5-day forced swimming test (FS) that we previously developed, swim immobility was induced in 3xTg Alzheimer's model mice and wild-type (WT) mice. After the initial 5-day FS, the next and last swimming session was performed at a 4-week interval, during which the immobility was reduced in 3xTg mice, but was maintained fully in WT mice. After FS, context-dependent fear learning was normally induced in WT mice, but was impaired in 3xTg mice, suggesting that FS may exaggerate cognitive deficits typical to 3xTg mice. Hippocampal long-term potentiation (LTP) at Schaffer collateral-CA1 synapses was suppressed by FS in WT mice, but not in 3xTg mice, indicating that FS modifies LTP in the WT mouse hippocampus, but not in 3xTg tissue. FS increased excitability of cingulate cortex pyramidal cells similarly in WT and 3xTg mice. Agreeing with our previous finding that expression of Homer1a protein is decreased in the cingulate cortex in harmony with FS-induced immobility, western blot showed that Homer1a expression is reduced by FS in the WT mice. In 3xTg mice, by contrast, FS failed to reduce Homer1a expression. The disrupted endurance of FS-induced immobility in 3xTg mice appears to be attributable to impaired cognition typical to this genotype. Failure of FS to alter LTP magnitude might be related to unaltered Homer1a expression after FS in 3xTg mice.
Collapse
Affiliation(s)
- Xianwen Luo
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan.,Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yuan Shui
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan
| | - Furong Wang
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan.,Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ryo Yamamoto
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan
| | - Nobuo Kato
- Department of Physiology, Kanazawa Medical University, Ishikawa 920-0293, Japan
| |
Collapse
|
83
|
Buscemi L, Ginet V, Lopatar J, Montana V, Pucci L, Spagnuolo P, Zehnder T, Grubišić V, Truttman A, Sala C, Hirt L, Parpura V, Puyal J, Bezzi P. Homer1 Scaffold Proteins Govern Ca2+ Dynamics in Normal and Reactive Astrocytes. Cereb Cortex 2017; 27:2365-2384. [PMID: 27075036 PMCID: PMC5963825 DOI: 10.1093/cercor/bhw078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In astrocytes, the intracellular calcium (Ca2+) signaling mediated by activation of metabotropic glutamate receptor 5 (mGlu5) is crucially involved in the modulation of many aspects of brain physiology, including gliotransmission. Here, we find that the mGlu5-mediated Ca2+ signaling leading to release of glutamate is governed by mGlu5 interaction with Homer1 scaffolding proteins. We show that the long splice variants Homer1b/c are expressed in astrocytic processes, where they cluster with mGlu5 at sites displaying intense local Ca2+ activity. We show that the structural and functional significance of the Homer1b/c-mGlu5 interaction is to relocate endoplasmic reticulum (ER) to the proximity of the plasma membrane and to optimize Ca2+ signaling and glutamate release. We also show that in reactive astrocytes the short dominant-negative splice variant Homer1a is upregulated. Homer1a, by precluding the mGlu5-ER interaction decreases the intensity of Ca2+ signaling thus limiting the intensity and the duration of glutamate release by astrocytes. Hindering upregulation of Homer1a with a local injection of short interfering RNA in vivo restores mGlu5-mediated Ca2+ signaling and glutamate release and sensitizes astrocytes to apoptosis. We propose that Homer1a may represent one of the cellular mechanisms by which inflammatory astrocytic reactions are beneficial for limiting brain injury.
Collapse
Affiliation(s)
- Lara Buscemi
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Vanessa Ginet
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Jan Lopatar
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Vedrana Montana
- Department of Biotechnology, University of Rijeka, 51000 Rijeka, Croatia
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Luca Pucci
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Paola Spagnuolo
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Tamara Zehnder
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| | - Vladimir Grubišić
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Anita Truttman
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Carlo Sala
- CNR Institute of Neuroscience and Department of Biotechnology and Translational Medicine, University of Milan, Milan, Italy
| | - Lorenz Hirt
- Stroke Laboratory, Neurology Service, Department of Clinical Neurosciences, University Hospital Centre and University of Lausanne, CH-1011 Lausanne, Switzerland
| | - Vladimir Parpura
- Department of Neurobiology, Center for Glial Biology in Medicine, Civitan International Research Center, Atomic Force Microscopy and Nanotechnology Laboratories, and Evelyn F. McKnight Brain Institute, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Julien Puyal
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
- Division of Neonatology, Department of Paediatrics and Paediatric Surgery, University Hospital Centre and University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Paola Bezzi
- Department of Fundamental Neurosciences, University of Lausanne, CH1005Lausanne, Switzerland
| |
Collapse
|
84
|
Diering GH, Nirujogi RS, Roth RH, Worley PF, Pandey A, Huganir RL. Homer1a drives homeostatic scaling-down of excitatory synapses during sleep. Science 2017; 355:511-515. [PMID: 28154077 DOI: 10.1126/science.aai8355] [Citation(s) in RCA: 323] [Impact Index Per Article: 46.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 12/08/2016] [Indexed: 12/30/2022]
Abstract
Sleep is an essential process that supports learning and memory by acting on synapses through poorly understood molecular mechanisms. Using biochemistry, proteomics, and imaging in mice, we find that during sleep, synapses undergo widespread alterations in composition and signaling, including weakening of synapses through removal and dephosphorylation of synaptic AMPA-type glutamate receptors. These changes are driven by the immediate early gene Homer1a and signaling from group I metabotropic glutamate receptors mGluR1/5. Homer1a serves as a molecular integrator of arousal and sleep need via the wake- and sleep-promoting neuromodulators, noradrenaline and adenosine, respectively. Our data suggest that homeostatic scaling-down, a global form of synaptic plasticity, is active during sleep to remodel synapses and participates in the consolidation of contextual memory.
Collapse
Affiliation(s)
- Graham H Diering
- Solomon Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Raja S Nirujogi
- Department of Biological Chemistry, Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Richard H Roth
- Solomon Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Paul F Worley
- Solomon Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA
| | - Akhilesh Pandey
- Department of Biological Chemistry, Institute of Genetic Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Richard L Huganir
- Solomon Snyder Department of Neuroscience, Kavli Neuroscience Discovery Institute, Johns Hopkins University, Baltimore, MD, USA.
| |
Collapse
|
85
|
Niu Y, Dai Z, Liu W, Zhang C, Yang Y, Guo Z, Li X, Xu C, Huang X, Wang Y, Shi YS, Liu JJ. Ablation of SNX6 leads to defects in synaptic function of CA1 pyramidal neurons and spatial memory. eLife 2017; 6. [PMID: 28134614 PMCID: PMC5323044 DOI: 10.7554/elife.20991] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2016] [Accepted: 01/28/2017] [Indexed: 11/14/2022] Open
Abstract
SNX6 is a ubiquitously expressed PX-BAR protein that plays important roles in retromer-mediated retrograde vesicular transport from endosomes. Here we report that CNS-specific Snx6 knockout mice exhibit deficits in spatial learning and memory, accompanied with loss of spines from distal dendrites of hippocampal CA1 pyramidal cells. SNX6 interacts with Homer1b/c, a postsynaptic scaffold protein crucial for the synaptic distribution of other postsynaptic density (PSD) proteins and structural integrity of dendritic spines. We show that SNX6 functions independently of retromer to regulate distribution of Homer1b/c in the dendritic shaft. We also find that Homer1b/c translocates from shaft to spines by protein diffusion, which does not require SNX6. Ablation of SNX6 causes reduced distribution of Homer1b/c in distal dendrites, decrease in surface levels of AMPAR and impaired AMPAR-mediated synaptic transmission. These findings reveal a physiological role of SNX6 in CNS excitatory neurons. DOI:http://dx.doi.org/10.7554/eLife.20991.001 Neurons are the building blocks of the nervous system. These cells generally consist of a round portion called the cell body and a long cable-like axon. The cell body bears numerous branches called dendrites, which are in turn covered in spines. Neurons communicate with one another at junctions – or synapses – that typically form between the end of the axon of one cell and a dendritic spine on another. Specialized proteins stabilize the dendritic spines and enable the cells to exchange messages across the synapse. However, it is the cell body – rather than the dendrites – that produces most of these proteins. Structures called molecular motors transport proteins to their destinations within the cell along fixed tracks, similar to how a freight train carries cargo over the rail network. One of the key molecular motors within neurons is called dynein‒dynactin. This in turn interacts with other proteins called adaptors, enabling it to transport specific types of cargo. Niu, Dai, Liu et al. have now examined the role of SNX6, an adaptor protein for the dynein‒dynactin motor. Mice that have been genetically modified to lack SNX6 in their brains have fewer spines on their dendrites compared with normal mice. This was particularly true for dendrites that contain AMPAR, a protein that receives signals sent across synapses. Niu, Dai, Liu et al. showed that SNX6 interacts with another protein called Homer1b/c and is responsible for distributing this protein in dendrites far from the cell body. The Homer1b/c protein helps to stabilize dendritic spines and to regulate the number of AMPAR proteins within them. Mice that lack SNX6 therefore have less Homer1b/c in the dendrites furthest from the cell body, and fewer spines on these dendrites too. These mice also have fewer AMPAR proteins at their synapses than control mice. Mice that lack SNX6 show impaired learning and memory compared to control mice. This is consistent with the fact that changes in the strength of synapses that possess AMPAR proteins are thought to underlie learning and memory. Additional experiments are required to explore these relationships further, and to determine whether SNX6 helps to localize any other proteins that also contribute to changes in the strength of synapses. DOI:http://dx.doi.org/10.7554/eLife.20991.002
Collapse
Affiliation(s)
- Yang Niu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Graduate School, University of Chinese Academy of Sciences, Beijing, China
| | - Zhonghua Dai
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Wenxue Liu
- Department of Anesthesiology, Jinling Hospital, School of Medicine, Nanjing University, Nanjing, China.,State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China.,MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China.,Model Animal Research Center, Nanjing University, Nanjing, China
| | - Cheng Zhang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Yanrui Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Zhenzhen Guo
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Graduate School, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoyu Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,Graduate School, University of Chinese Academy of Sciences, Beijing, China
| | - Chenchang Xu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China.,Graduate School, University of Chinese Academy of Sciences, Beijing, China
| | - Xiahe Huang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Yun S Shi
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China.,MOE Key Laboratory of Model Animal for Disease Study, Nanjing University, Nanjing, China.,Model Animal Research Center, Nanjing University, Nanjing, China
| | - Jia-Jia Liu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China.,CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| |
Collapse
|
86
|
Kalinowska M, Francesconi A. Group I Metabotropic Glutamate Receptor Interacting Proteins: Fine-Tuning Receptor Functions in Health and Disease. Curr Neuropharmacol 2017; 14:494-503. [PMID: 27296642 PMCID: PMC4983749 DOI: 10.2174/1570159x13666150515234434] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 04/24/2015] [Accepted: 05/12/2015] [Indexed: 11/22/2022] Open
Abstract
Group I metabotropic glutamate receptors mediate slow excitatory neurotransmission in the central nervous system and are critical to activity-dependent synaptic plasticity, a cellular substrate of learning and memory. Dysregulated receptor signaling is implicated in neuropsychiatric conditions ranging from neurodevelopmental to neurodegenerative disorders. Importantly, group I metabotropic glutamate receptor signaling functions can be modulated by interacting proteins that mediate receptor trafficking, expression and coupling efficiency to signaling effectors. These interactions afford cell- or pathway-specific modulation to fine-tune receptor function, thus representing a potential target for pharmacological interventions in pathological conditions.
Collapse
Affiliation(s)
| | - Anna Francesconi
- Dominick P. Purpura Department of Neuroscience, Rose F. Kennedy Center, Room 706, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
| |
Collapse
|
87
|
Tomasetti C, Iasevoli F, Buonaguro EF, De Berardis D, Fornaro M, Fiengo ALC, Martinotti G, Orsolini L, Valchera A, Di Giannantonio M, de Bartolomeis A. Treating the Synapse in Major Psychiatric Disorders: The Role of Postsynaptic Density Network in Dopamine-Glutamate Interplay and Psychopharmacologic Drugs Molecular Actions. Int J Mol Sci 2017; 18:E135. [PMID: 28085108 PMCID: PMC5297768 DOI: 10.3390/ijms18010135] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 12/25/2016] [Accepted: 01/08/2017] [Indexed: 12/20/2022] Open
Abstract
Dopamine-glutamate interplay dysfunctions have been suggested as pathophysiological key determinants of major psychotic disorders, above all schizophrenia and mood disorders. For the most part, synaptic interactions between dopamine and glutamate signaling pathways take part in the postsynaptic density, a specialized ultrastructure localized under the membrane of glutamatergic excitatory synapses. Multiple proteins, with the role of adaptors, regulators, effectors, and scaffolds compose the postsynaptic density network. They form structural and functional crossroads where multiple signals, starting at membrane receptors, are received, elaborated, integrated, and routed to appropriate nuclear targets. Moreover, transductional pathways belonging to different receptors may be functionally interconnected through postsynaptic density molecules. Several studies have demonstrated that psychopharmacologic drugs may differentially affect the expression and function of postsynaptic genes and proteins, depending upon the peculiar receptor profile of each compound. Thus, through postsynaptic network modulation, these drugs may induce dopamine-glutamate synaptic remodeling, which is at the basis of their long-term physiologic effects. In this review, we will discuss the role of postsynaptic proteins in dopamine-glutamate signals integration, as well as the peculiar impact of different psychotropic drugs used in clinical practice on postsynaptic remodeling, thereby trying to point out the possible future molecular targets of "synapse-based" psychiatric therapeutic strategies.
Collapse
Affiliation(s)
- Carmine Tomasetti
- NHS, Department of Mental Health ASL Teramo, Psychiatric Service of Diagnosis and Treatment, Hospital "Maria SS dello Splendore", 641021 Giulianova, Italy.
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Reproductive and Odontostomatogical Sciences, University of Naples "Federico II", 80131 Napoli, Italy.
- Polyedra Research Group, 64100 Teramo, Italy.
| | - Felice Iasevoli
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Reproductive and Odontostomatogical Sciences, University of Naples "Federico II", 80131 Napoli, Italy.
- Polyedra Research Group, 64100 Teramo, Italy.
| | - Elisabetta Filomena Buonaguro
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Reproductive and Odontostomatogical Sciences, University of Naples "Federico II", 80131 Napoli, Italy.
- Polyedra Research Group, 64100 Teramo, Italy.
| | - Domenico De Berardis
- Polyedra Research Group, 64100 Teramo, Italy.
- NHS, Department of Mental Health ASL Teramo, Psychiatric Service of Diagnosis and Treatment, Hospital "G. Mazzini", 64100 Teramo, Italy.
- Department of Neuroscience and Imaging, University "G. d'Annunzio", 66100 Chieti, Italy.
| | - Michele Fornaro
- Polyedra Research Group, 64100 Teramo, Italy.
- New York State Psychiatric Institute, Columbia University, New York, NY 10027, USA.
| | | | - Giovanni Martinotti
- Polyedra Research Group, 64100 Teramo, Italy.
- Department of Neuroscience and Imaging, University "G. d'Annunzio", 66100 Chieti, Italy.
| | - Laura Orsolini
- Polyedra Research Group, 64100 Teramo, Italy.
- Casa di Cura Villa San Giuseppe, 63100 Ascoli Piceno, Italy.
| | - Alessandro Valchera
- Polyedra Research Group, 64100 Teramo, Italy.
- Casa di Cura Villa San Giuseppe, 63100 Ascoli Piceno, Italy.
| | | | - Andrea de Bartolomeis
- Laboratory of Molecular and Translational Psychiatry, Department of Neuroscience, Reproductive and Odontostomatogical Sciences, University of Naples "Federico II", 80131 Napoli, Italy.
| |
Collapse
|
88
|
Ryskamp D, Wu J, Geva M, Kusko R, Grossman I, Hayden M, Bezprozvanny I. The sigma-1 receptor mediates the beneficial effects of pridopidine in a mouse model of Huntington disease. Neurobiol Dis 2017; 97:46-59. [PMID: 27818324 PMCID: PMC5214572 DOI: 10.1016/j.nbd.2016.10.006] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 09/13/2016] [Accepted: 10/30/2016] [Indexed: 11/25/2022] Open
Abstract
The tri-nucleotide repeat expansion underlying Huntington disease (HD) results in corticostriatal synaptic dysfunction and subsequent neurodegeneration of striatal medium spiny neurons (MSNs). HD is a devastating autosomal dominant disease with no disease-modifying treatments. Pridopidine, a postulated "dopamine stabilizer", has been shown to improve motor symptoms in clinical trials of HD. However, the target(s) and mechanism of action of pridopidine remain to be fully elucidated. As binding studies identified sigma-1 receptor (S1R) as a high-affinity receptor for pridopidine, we evaluated the relevance of S1R as a therapeutic target of pridopidine in HD. S1R is an endoplasmic reticulum - (ER) resident transmembrane protein and is regulated by ER calcium homeostasis, which is perturbed in HD. Consistent with ER calcium dysregulation, we observed striatal upregulation of S1R in aged YAC128 transgenic HD mice and HD patients. We previously demonstrated that dendritic MSN spines are lost in aged corticostriatal co-cultures from YAC128 mice. We report here that pridopidine and the chemically similar S1R agonist 3-PPP prevent MSN spine loss in aging YAC128 co-cultures. Spine protection was blocked by neuronal deletion of S1R. Pridopidine treatment suppressed supranormal ER Ca2+ release, restored ER calcium levels and reduced excessive store-operated calcium (SOC) entry in spines, which may account for its synaptoprotective effects. Normalization of ER Ca2+ levels by pridopidine was prevented by S1R deletion. To evaluate long-term effects of pridopidine, we analyzed expression profiles of calcium signaling genes. Pridopidine elevated striatal expression of calbindin and homer1a, whereas their striatal expression was reduced in aged Q175KI and YAC128 HD mouse models compared to WT. Pridopidine and 3-PPP are proposed to prevent calcium dysregulation and synaptic loss in a YAC128 corticostriatal co-culture model of HD. The actions of pridopidine were mediated by S1R and led to normalization of ER Ca2+ release, ER Ca2+ levels and spine SOC entry in YAC128 MSNs. This is a new potential mechanism of action for pridopidine, highlighting S1R as a potential target for HD therapy. Upregulation of striatal proteins that regulate calcium, including calbindin and homer1a, upon chronic therapy with pridopidine, may further contribute to long-term beneficial effects of pridopidine in HD.
Collapse
Affiliation(s)
- Daniel Ryskamp
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Jun Wu
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Michal Geva
- Teva Pharmaceutical Industries, 5 Basel St., Petach Tikva 49131, Israel.
| | | | - Iris Grossman
- Teva Pharmaceutical Industries, 5 Basel St., Petach Tikva 49131, Israel.
| | - Michael Hayden
- Teva Pharmaceutical Industries, 5 Basel St., Petach Tikva 49131, Israel.
| | - Ilya Bezprozvanny
- Department of Physiology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| |
Collapse
|
89
|
Duncan RS, Hwang SY, Koulen P. Effects of Vesl/Homer Proteins on Intracellular Signaling. Exp Biol Med (Maywood) 2016; 230:527-35. [PMID: 16118402 DOI: 10.1177/153537020523000803] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The clustering of signaling molecules at specialized cellular sites allows cells to effectively convert extracellular signals into intracellular signals and to produce a concerted functional output with specific temporal and spatial patterns. A prime example for these molecules and their effects on cellular signaling are the postsynaptic density proteins of the central nervous system. Recently, one group of these proteins, the Vesl/Homer protein family has received increased attention because of its unique molecular properties that allow both the clustering end functional modulation of a plethora of different binding Proteins. Within multlprotein signaling complexes, Vesl/Homer Proteins influence proteins as diverse as metabotropic glutamate receptors; transient receptor potential channels; intracellular calcium channels; the scaffolding protein, Shank; small GTPases; transcription factors; and cytoskeletal proteins. Furthermore, interaction with such functionally relevant proteins also links Vesl/Homer proteins indirectly to an even larger group of cellular effector proteins, putting the Vesl/Homer Proteins at the crossroads of several critical intracellular signaling processes. In addition to the initial reports of Vesl/Homer protein expression in the central nervous system, members of this protein family have now been identified in other excitable cells in various muscle types and in a large number of nonexcitable cells. The widespread expression of Vesl/Homer proteins in different organs and their functional importance in cellular protein signaling complexes is further evidenced by their conservation in organisms from Drosoohila to humans.
Collapse
Affiliation(s)
- R Scott Duncan
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center at Fort Worth, 3500 Camp Bowie Boulevard, Fort Worth, Texas 76107-2699, USA
| | | | | |
Collapse
|
90
|
Pin JP, Bettler B. Organization and functions of mGlu and GABAB receptor complexes. Nature 2016; 540:60-68. [DOI: 10.1038/nature20566] [Citation(s) in RCA: 155] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2016] [Accepted: 10/21/2016] [Indexed: 02/08/2023]
|
91
|
Hoffmann HM, Crouzin N, Moreno E, Raivio N, Fuentes S, McCormick PJ, Ortiz J, Vignes M. Long-Lasting Impairment of mGluR5-Activated Intracellular Pathways in the Striatum After Withdrawal of Cocaine Self-Administration. Int J Neuropsychopharmacol 2016; 20:72-82. [PMID: 27744406 PMCID: PMC5412585 DOI: 10.1093/ijnp/pyw086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 09/22/2016] [Indexed: 12/04/2022] Open
Abstract
BACKGROUND Cocaine addiction continues to be a major heath concern, and despite public health intervention there is a lack of efficient pharmacological treatment options. A newly identified potential target are the group I metabotropic glutamate receptors, with allosteric modulators showing particular promise. METHODS We evaluated the capacity of group I metabotropic glutamate receptors to induce functional responses in ex vivo striatal slices from rats with (1) acute cocaine self-administration, (2) chronic cocaine self-administration, and (3) 60 days cocaine self-administration withdrawal by Western blot and extracellular recordings of synaptic transmission. RESULTS We found that striatal group I metabotropic glutamate receptors are the principal mediator of the mGluR1/5 agonist (RS)-3,5-dihydroxyphenylglycine-induced cAMP responsive-element binding protein phosphorylation. Both acute and chronic cocaine self-administration blunted group I metabotropic glutamate receptor effects on cAMP responsive-element binding protein phosphorylation in the striatum, which correlated with the capacity to induce long-term depression, an effect that was maintained 60 days after chronic cocaine self-administration withdrawal. In the nucleus accumbens, the principal brain region mediating the rewarding effects of drugs, chronic cocaine self-administration blunted group I metabotropic glutamate receptor stimulation of extracellular signal-regulated protein kinases 1/2 and cAMP responsive-element binding protein. Interestingly, the group I metabotropic glutamate receptor antagonist/inverse-agonist, 2-methyl-6-(phenylethynyl)pyridine hydrochloride, led to a specific increase in cAMP responsive-element binding protein phosphorylation after chronic cocaine self-administration, specifically in the nucleus accumbens, but not in the striatum. CONCLUSIONS Prolonged cocaine self-administration, through withdrawal, leads to a blunting of group I metabotropic glutamate receptor responses in the striatum. In addition, specifically in the accumbens, group I metabotropic glutamate receptor signaling to cAMP responsive-element binding protein shifts from an agonist-induced to an antagonist-induced cAMP responsive-element binding protein phosphorylation.
Collapse
Affiliation(s)
- Hanne Mette Hoffmann
- Oxidative Stress and Neuroprotection, IBMM, CNRS UMR-5247, University of Montpellier II, Montpellier, France (Drs Hoffmann, Crouzin, and Vignes); Neuroscience Institute and Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autonoma de Barcelona, Bellaterra, Spain (Dr Hoffmann, Ms Raivio, Dr Fuentes, and Dr Ortiz); Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Spain (Drs Moreno and McCormick); University of East Anglia, School of Pharmacy, NR4 7TJ, Norwich, United Kingdom (Dr McCormick)
| | - Nadine Crouzin
- Oxidative Stress and Neuroprotection, IBMM, CNRS UMR-5247, University of Montpellier II, Montpellier, France (Drs Hoffmann, Crouzin, and Vignes); Neuroscience Institute and Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autonoma de Barcelona, Bellaterra, Spain (Dr Hoffmann, Ms Raivio, Dr Fuentes, and Dr Ortiz); Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Spain (Drs Moreno and McCormick); University of East Anglia, School of Pharmacy, NR4 7TJ, Norwich, United Kingdom (Dr McCormick)
| | - Estefanía Moreno
- Oxidative Stress and Neuroprotection, IBMM, CNRS UMR-5247, University of Montpellier II, Montpellier, France (Drs Hoffmann, Crouzin, and Vignes); Neuroscience Institute and Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autonoma de Barcelona, Bellaterra, Spain (Dr Hoffmann, Ms Raivio, Dr Fuentes, and Dr Ortiz); Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Spain (Drs Moreno and McCormick); University of East Anglia, School of Pharmacy, NR4 7TJ, Norwich, United Kingdom (Dr McCormick)
| | - Noora Raivio
- Oxidative Stress and Neuroprotection, IBMM, CNRS UMR-5247, University of Montpellier II, Montpellier, France (Drs Hoffmann, Crouzin, and Vignes); Neuroscience Institute and Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autonoma de Barcelona, Bellaterra, Spain (Dr Hoffmann, Ms Raivio, Dr Fuentes, and Dr Ortiz); Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Spain (Drs Moreno and McCormick); University of East Anglia, School of Pharmacy, NR4 7TJ, Norwich, United Kingdom (Dr McCormick)
| | - Silvia Fuentes
- Oxidative Stress and Neuroprotection, IBMM, CNRS UMR-5247, University of Montpellier II, Montpellier, France (Drs Hoffmann, Crouzin, and Vignes); Neuroscience Institute and Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autonoma de Barcelona, Bellaterra, Spain (Dr Hoffmann, Ms Raivio, Dr Fuentes, and Dr Ortiz); Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Spain (Drs Moreno and McCormick); University of East Anglia, School of Pharmacy, NR4 7TJ, Norwich, United Kingdom (Dr McCormick)
| | - Peter J. McCormick
- Oxidative Stress and Neuroprotection, IBMM, CNRS UMR-5247, University of Montpellier II, Montpellier, France (Drs Hoffmann, Crouzin, and Vignes); Neuroscience Institute and Department of Biochemistry and Molecular Biology, School of Medicine, Universitat Autonoma de Barcelona, Bellaterra, Spain (Dr Hoffmann, Ms Raivio, Dr Fuentes, and Dr Ortiz); Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas. Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Barcelona, Spain (Drs Moreno and McCormick); University of East Anglia, School of Pharmacy, NR4 7TJ, Norwich, United Kingdom (Dr McCormick)
| | - Jordi Ortiz
- Present address (H.M.H.): Department of Reproductive Medicine, 349 Leichtag Biomedical Research Building, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0674
| | | |
Collapse
|
92
|
Physical interaction between neurofibromin and serotonin 5-HT6 receptor promotes receptor constitutive activity. Proc Natl Acad Sci U S A 2016; 113:12310-12315. [PMID: 27791021 DOI: 10.1073/pnas.1600914113] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Active G protein-coupled receptor (GPCR) conformations not only are promoted by agonists but also occur in their absence, leading to constitutive activity. Association of GPCRs with intracellular protein partners might be one of the mechanisms underlying GPCR constitutive activity. Here, we show that serotonin 5 hydroxytryptamine 6 (5-HT6) receptor constitutively activates the Gs/adenylyl cyclase pathway in various cell types, including neurons. Constitutive activity is strongly reduced by silencing expression of the Ras-GTPase activating protein (Ras-GAP) neurofibromin, a 5-HT6 receptor partner. Neurofibromin is a multidomain protein encoded by the NF1 gene, the mutation of which causes Neurofibromatosis type 1 (NF1), a genetic disorder characterized by multiple benign and malignant nervous system tumors and cognitive deficits. Disrupting association of 5-HT6 receptor with neurofibromin Pleckstrin Homology (PH) domain also inhibits receptor constitutive activity, and PH domain expression rescues 5-HT6 receptor-operated cAMP signaling in neurofibromin-deficient cells. Furthermore, PH domains carrying mutations identified in NF1 patients that prevent interaction with the 5-HT6 receptor fail to rescue receptor constitutive activity in neurofibromin-depleted cells. Further supporting a role of neurofibromin in agonist-independent Gs signaling elicited by native receptors, the phosphorylation of cAMP-responsive element-binding protein (CREB) is strongly decreased in prefrontal cortex of Nf1+/- mice compared with WT mice. Moreover, systemic administration of a 5-HT6 receptor inverse agonist reduces CREB phosphorylation in prefrontal cortex of WT mice but not Nf1+/- mice. Collectively, these findings suggest that disrupting 5-HT6 receptor-neurofibromin interaction prevents agonist-independent 5-HT6 receptor-operated cAMP signaling in prefrontal cortex, an effect that might underlie neuronal abnormalities in NF1 patients.
Collapse
|
93
|
Ade KK, Wan Y, Hamann HC, O’Hare JK, Guo W, Quian A, Kumar S, Bhagat S, Rodriguiz RM, Wetsel WC, Conn PJ, Dzirasa K, Huber KM, Calakos N. Increased Metabotropic Glutamate Receptor 5 Signaling Underlies Obsessive-Compulsive Disorder-like Behavioral and Striatal Circuit Abnormalities in Mice. Biol Psychiatry 2016; 80:522-33. [PMID: 27436084 PMCID: PMC5536332 DOI: 10.1016/j.biopsych.2016.04.023] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 04/29/2016] [Accepted: 04/29/2016] [Indexed: 01/15/2023]
Abstract
BACKGROUND Development of treatments for obsessive-compulsive disorder (OCD) is hampered by a lack of mechanistic understanding about this prevalent neuropsychiatric condition. Although circuit changes such as elevated frontostriatal activity are linked to OCD, the underlying molecular signaling that drives OCD-related behaviors remains largely unknown. Here, we examine the significance of type 5 metabotropic glutamate receptors (mGluR5s) for behavioral and circuit abnormalities relevant to OCD. METHODS Sapap3 knockout (KO) mice treated acutely with an mGluR5 antagonist were evaluated for OCD-relevant phenotypes of self-grooming, anxiety-like behaviors, and increased striatal activity. The role of mGluR5 in the striatal circuit abnormalities of Sapap3 KO mice was further explored using two-photon calcium imaging to monitor striatal output from the direct and indirect pathways. A contribution of constitutive signaling to increased striatal mGluR5 activity in Sapap3 KO mice was investigated using pharmacologic and biochemical approaches. Finally, sufficiency of mGluR5 to drive OCD-like behavior in wild-type mice was tested by potentiating mGluR5 with a positive allosteric modulator. RESULTS Excessive mGluR5 signaling underlies OCD-like behaviors and striatal circuit abnormalities in Sapap3 KO mice. Accordingly, enhancing mGluR5 activity acutely recapitulates these behavioral phenotypes in wild-type mice. In Sapap3 KO mice, elevated mGluR5 signaling is associated with constitutively active receptors and increased and imbalanced striatal output that is acutely corrected by antagonizing striatal mGluR5. CONCLUSIONS These findings demonstrate a causal role for increased mGluR5 signaling in driving striatal output abnormalities and behaviors with relevance to OCD and show the tractability of acute mGluR5 inhibition to remedy circuit and behavioral abnormalities.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | - Nicole Calakos
- Departments of Neurology, Duke University Medical Center, Durham, North Carolina; Neurobiology, Duke University Medical Center, Durham, North Carolina.
| |
Collapse
|
94
|
Jones OD. Do group I metabotropic glutamate receptors mediate LTD? Neurobiol Learn Mem 2016; 138:85-97. [PMID: 27545442 DOI: 10.1016/j.nlm.2016.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/01/2016] [Accepted: 08/17/2016] [Indexed: 01/31/2023]
Abstract
Synapses undergo significant structural and functional reorganization in response to varying patterns of stimulation. These forms of plasticity are considered fundamental to cognition and neuronal homeostasis. An increasing number of reports highlight the importance of activity-dependent synaptic strengthening (long term potentiation: LTP) for learning. However, the functional significance of activity-dependent weakening of synapses (long term depression: LTD) remains relatively poorly understood. One form of synaptic weakening, induced by group I metabotropic glutamate receptors (mGluRs), has received significant attention from a mechanistic point of view and because of its augmentation in a murine model of Fragile X Syndrome. Yet, studies of this form of plasticity often yield confusing, contradictory results. These conflicting findings are likely attributable to the bulk stimulation and recording techniques often used to study synaptic plasticity (typically involving evoked extracellular recordings, which represent the summed activity of many synapses). Such studies inherently blur the identity of the synapses undergoing change, thus giving the illusion that synapses per se are being modified when in fact this may only be true of a specific subset of synapses. Indeed, studies employing minimal synaptic activation paint a fundamentally different picture of what is commonly called "mGluR-LTD". Here, I review the evidence in favour of group I mGluRs as mediators of various forms of synaptic downregulation and attempt to explain discrepancies in the literature. I argue that, while multiple forms of synaptic weakening may be triggered by these receptors, the canonical form of group I mGluR-mediated depression, mGluR-LTD, is in fact not a depression of basal synaptic responses. Rather, it is a reversal of established LTP and thus a form of depotentiation. Far from being arbitrary, this distinction has significant implications for the role of group I mGluRs in cognition, both in the healthy brain and in pathological conditions. Further, the differential actions of group I mGluRs at naïve and potentiated synapses suggest these receptors signal in a state-dependent manner to regulate various stages of the learning process.
Collapse
Affiliation(s)
- Owen D Jones
- Department of Psychology, Brain Health Research Centre & Brain Research New Zealand, University of Otago, Dunedin, New Zealand.
| |
Collapse
|
95
|
Metabotropic glutamate receptor, mGlu5, regulates hippocampal synaptic plasticity and is required for tetanisation-triggered changes in theta and gamma oscillations. Neuropharmacology 2016; 115:20-29. [PMID: 27395786 DOI: 10.1016/j.neuropharm.2016.06.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 06/01/2016] [Accepted: 06/02/2016] [Indexed: 01/04/2023]
Abstract
Hippocampal synaptic plasticity and learning are regulated by metabotropic glutamate receptors (mGlu) and particularly by mGlu5. In the hippocampus, synaptic plasticity is tightly linked to neuronal network oscillations in theta (5-10 Hz) and gamma (∼30-100 Hz) frequency ranges, and specific changes in theta and gamma spectral power can predict for the success of patterned afferent stimulation in inducing robust long-term potentiation (LTP). In this study, we hypothesized that activation of mGlu5 mediates tetanisation-driven changes in network oscillations and thereby determines the longevity of LTP. To explore this, we applied high-frequency stimulation (HFS) to the perforant path input to the dentate gyrus (DG), in the presence of the negative allosteric modulator, 2-methyl-6-(phenylethynyl)pyridine (MPEP), or the positive allosteric modulator (S)-(4-fluorophenyl)-[3-(3-(3-(4-fluorophenyl)-[1,2,4]oxadiazol-5-yl)-piperidin-1-yl)]methanone (ADX47273). In freely behaving rats, administration of MPEP resulted in a significant impairment, whereas treatment with ADX47273 led to a significant enhancement, of LTP (>24 h) compared to vehicle-treated controls. Allosteric potentiation of mGlu5 also resulted in a significantly greater increase of the spectral power of theta and gamma oscillations within the period of 300 s after HFS, as compared to MPEP-treated animals or controls. Our findings show that the regulation of hippocampal LTP by mGlu5 is associated with modulation of network oscillatory activity in the period shortly after LTP induction. Taken together, these data demonstrate that changes in the spectral contents of local field activity that occur in response to patterned afferent stimulation require activation of mGlu5 and may be instrumental for the successful expression of persistent LTP. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
Collapse
|
96
|
Fernandes D, Carvalho AL. Mechanisms of homeostatic plasticity in the excitatory synapse. J Neurochem 2016; 139:973-996. [PMID: 27241695 DOI: 10.1111/jnc.13687] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Revised: 05/25/2016] [Accepted: 05/27/2016] [Indexed: 11/30/2022]
Abstract
Brain development, sensory information processing, and learning and memory processes depend on Hebbian forms of synaptic plasticity, and on the remodeling and pruning of synaptic connections. Neurons in networks implicated in these processes carry out their functions while facing constant perturbation; homeostatic responses are therefore required to maintain neuronal activity within functional ranges for proper brain function. Here, we will review in vitro and in vivo studies demonstrating that several mechanisms underlie homeostatic plasticity of excitatory synapses, and identifying participant molecular players. Emerging evidence suggests a link between disrupted homeostatic synaptic plasticity and neuropsychiatric and neurologic disorders. Hebbian forms of synaptic plasticity, such as long-term potentiation (LTP), induce long-lasting changes in synaptic strength, which can be destabilizing and drive activity to saturation. Conversely, homeostatic plasticity operates to compensate for prolonged activity changes, stabilizing neuronal firing within a dynamic physiological range. We review mechanisms underlying homeostatic plasticity, and address how neurons integrate distinct forms of plasticity for proper brain function. This article is part of a mini review series: "Synaptic Function and Dysfunction in Brain Diseases".
Collapse
Affiliation(s)
- Dominique Fernandes
- CNC-Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,PDBEB-Doctoral Program in Experimental Biology and Biomedicine, Interdisciplinary Research Institute (III-UC), University of Coimbra, Coimbra, Portugal
| | - Ana Luísa Carvalho
- CNC-Centre for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal.,Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| |
Collapse
|
97
|
Selective Disruption of Metabotropic Glutamate Receptor 5-Homer Interactions Mimics Phenotypes of Fragile X Syndrome in Mice. J Neurosci 2016; 36:2131-47. [PMID: 26888925 DOI: 10.1523/jneurosci.2921-15.2016] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
UNLABELLED Altered function of the Gq-coupled, Group 1 metabotropic glutamate receptors, specifically mGlu5, is implicated in multiple mouse models of autism and intellectual disability. mGlu5 dysfunction has been most well characterized in the fragile X syndrome mouse model, the Fmr1 knock-out (KO) mouse, where pharmacological and genetic reduction of mGlu5 reverses many phenotypes. mGlu5 is less associated with its scaffolding protein Homer in Fmr1 KO mice, and restoration of mGlu5-Homer interactions by genetic deletion of a short, dominant negative of Homer, H1a, rescues many phenotypes of Fmr1 KO mice. These results suggested that disruption of mGlu5-Homer leads to phenotypes of FXS. To test this idea, we examined mice with a knockin mutation of mGlu5 (F1128R; mGlu5(R/R)) that abrogates binding to Homer. Although FMRP levels were normal, mGlu5(R/R) mice mimicked multiple phenotypes of Fmr1 KO mice, including reduced mGlu5 association with the postsynaptic density, enhanced constitutive mGlu5 signaling to protein synthesis, deficits in agonist-induced translational control, protein synthesis-independent LTD, neocortical hyperexcitability, audiogenic seizures, and altered behaviors, including anxiety and sensorimotor gating. These results reveal new roles for the Homer scaffolds in regulation of mGlu5 function and implicate a specific molecular mechanism in a complex brain disease. SIGNIFICANCE STATEMENT Abnormal function of the metabotropic, or Gq-coupled, glutamate receptor 5 (mGlu5) has been implicated in neurodevelopmental disorders, including a genetic cause of intellectual disability and autism called fragile X syndrome. In brains of a mouse model of fragile X, mGlu5 is less associated with its binding partner Homer, a scaffolding protein that regulates mGlu5 localization to synapses and its ability to activate biochemical signaling pathways. Here we show that a mouse expressing a mutant mGlu5 that cannot bind to Homer is sufficient to mimic many of the biochemical, neurophysiological, and behavioral symptoms observed in the fragile X mouse. This work provides strong evidence that Homer-mGlu5 binding contributes to symptoms associated with neurodevelopmental disorders.
Collapse
|
98
|
Ric-8A gene deletion or phorbol ester suppresses tumorigenesis in a mouse model of GNAQ(Q209L)-driven melanoma. Oncogenesis 2016; 5:e236. [PMID: 27348266 PMCID: PMC4945744 DOI: 10.1038/oncsis.2016.45] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 05/06/2016] [Accepted: 05/11/2016] [Indexed: 01/19/2023] Open
Abstract
The heterotrimeric G protein α subunit oncogenes GNAQ or GNA11 carry Q209X or R183X activating mutations and are present with ~90% frequency in human uveal melanomas. Forced expression of GNAQ/11Q209L in melanocytes is sufficient to drive metastatic melanoma in immune-compromised mice. No known drugs directly target these oncogenic G proteins. Ric-8A is the molecular chaperone that selectively folds Gαq/i/13 subunits. Targeting Ric-8A serves as a rational, yet unexplored approach to reduce the functional abundance of oncogenic Gαq/11 in order to blunt cancer signaling. Here, using mouse melanocyte cell graft tumorigenesis models, we determined that Ric-8A genetic ablation attenuated the abundance and melanoma-driving potential of Gαq-Q209L. A new conditional Ric-8AFlox/Flox; Rosa-CreER+/− mouse strain was derived and used as a tissue source to culture an immortalized, tamoxifen-inducible Ric-8A knockout melanocyte cell line that required 12-O-tetradecanoylphorbol-13-acetate (TPA, phorbol ester) for growth. The cell line failed to grow tumors when grafted into immune-compromised mice regardless of Ric-8A expression. Stable expression of human GNAQQ209L, but not GNAQWT in the cell line promoted TPA-independent cell proliferation, and upon cell grafting in mice, the initiation and robust growth of darkly-pigmented melanoma tumors. Deletion of Ric-8A in GNAQQ209L cells restored TPA-dependent growth, reduced Gαq-Q209L below detectable levels and completely mitigated tumorigenesis from primary or secondary cell line grafts. Interestingly, TPA treatment of cultured GNAQQ209L cells or host animals grafted with GNAQQ209L cells also sharply reduced Gαq-Q209L abundance and tumorigenic capacity. Finally, tumorigenesis initiated from GNAQQ209L cell grafts, followed by host mouse systemic tamoxifen treatment to delete Ric-8A in the grafted cells completely abrogated GNAQQ209L-driven tumor progression unless a stable human RIC-8A transgene was used to rescue the floxed Ric-8A alleles. Our work defines two new rational targets that may be developed as potential uveal melanoma therapies through reduction of Gαq/11-Q209L oncoprotein abundance: (1) Ric-8A inhibition and (2) phorbol ester treatment.
Collapse
|
99
|
Olmo IG, Ferreira-Vieira TH, Ribeiro FM. Dissecting the Signaling Pathways Involved in the Crosstalk between Metabotropic Glutamate 5 and Cannabinoid Type 1 Receptors. Mol Pharmacol 2016; 90:609-619. [PMID: 27338080 DOI: 10.1124/mol.116.104372] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/16/2016] [Indexed: 02/06/2023] Open
Abstract
The metabotropic glutamate 5 receptor and the cannabinoid type 1 receptor are G protein-coupled receptors that are widely expressed in the central nervous system. Metabotropic glutamate 5 receptors, present at the postsynaptic site, are coupled to Gαq/11 proteins and display an excitatory response upon activation, whereas the cannabinoid type 1 receptor, mainly present at presynaptic terminals, is coupled to the Gi/o protein and triggers an inhibitory response. Recent studies suggest that the glutamatergic and endocannabinoid systems exhibit a functional interaction to modulate several neural processes. In this review, we discuss possible mechanisms involved in this crosstalk and its relationship with physiologic and pathologic conditions, including nociception, addiction, and fragile X syndrome.
Collapse
Affiliation(s)
- Isabella G Olmo
- Department of Biochemistry and Immunology, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Talita H Ferreira-Vieira
- Department of Biochemistry and Immunology, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Fabiola M Ribeiro
- Department of Biochemistry and Immunology, Instituto de Ciencias Biologicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| |
Collapse
|
100
|
Haas LT, Strittmatter SM. Oligomers of Amyloid β Prevent Physiological Activation of the Cellular Prion Protein-Metabotropic Glutamate Receptor 5 Complex by Glutamate in Alzheimer Disease. J Biol Chem 2016; 291:17112-21. [PMID: 27325698 DOI: 10.1074/jbc.m116.720664] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Indexed: 12/11/2022] Open
Abstract
The dysfunction and loss of synapses in Alzheimer disease are central to dementia symptoms. We have recently demonstrated that pathological Amyloid β oligomer (Aβo) regulates the association between intracellular protein mediators and the synaptic receptor complex composed of cellular prion protein (PrP(C)) and metabotropic glutamate receptor 5 (mGluR5). Here we sought to determine whether Aβo alters the physiological signaling of the PrP(C)-mGluR5 complex upon glutamate activation. We provide evidence that acute exposure to Aβo as well as chronic expression of familial Alzheimer disease mutant transgenes in model mice prevents protein-protein interaction changes of the complex induced by the glutamate analog 3,5-dihydroxyphenylglycine. We further show that 3,5-dihydroxyphenylglycine triggers the phosphorylation and activation of protein-tyrosine kinase 2-β (PTK2B, also referred to as Pyk2) and of calcium/calmodulin-dependent protein kinase II in wild-type brain slices but not in Alzheimer disease transgenic brain slices or wild-type slices incubated with Aβo. This study further distinguishes two separate Aβo-dependent signaling cascades, one dependent on extracellular Ca(2+) and Fyn kinase activation and the other dependent on the release of Ca(2+) from intracellular stores. Thus, Aβo triggers multiple distinct PrP(C)-mGluR5-dependent events implicated in neurodegeneration and dementia. We propose that targeting the PrP(C)-mGluR5 complex will reverse aberrant Aβo-triggered states of the complex to allow physiological fluctuations of glutamate signaling.
Collapse
Affiliation(s)
- Laura T Haas
- From the Cellular Neuroscience, Neurodegeneration, and Repair Program, Departments of Neurology and Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06536 and the Graduate School of Cellular and Molecular Neuroscience, University of Tübingen, 72074 Tübingen, Germany
| | - Stephen M Strittmatter
- From the Cellular Neuroscience, Neurodegeneration, and Repair Program, Departments of Neurology and Neuroscience, Yale University School of Medicine, New Haven, Connecticut 06536 and
| |
Collapse
|