1
|
Domin H, Burnat G. mGlu4R, mGlu7R, and mGlu8R allosteric modulation for treating acute and chronic neurodegenerative disorders. Pharmacol Rep 2024:10.1007/s43440-024-00657-7. [PMID: 39348087 DOI: 10.1007/s43440-024-00657-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2024] [Revised: 09/12/2024] [Accepted: 09/16/2024] [Indexed: 10/01/2024]
Abstract
Neuroprotection, defined as safeguarding neurons from damage and death by inhibiting diverse pathological mechanisms, continues to be a promising approach for managing a range of central nervous system (CNS) disorders, including acute conditions such as ischemic stroke and traumatic brain injury (TBI) and chronic neurodegenerative diseases like Parkinson's disease (PD), Alzheimer's disease (AD), and multiple sclerosis (MS). These pathophysiological conditions involve excessive glutamatergic (Glu) transmission activity, which can lead to excitotoxicity. Inhibiting this excessive Glu transmission has been proposed as a potential therapeutic strategy for treating the CNS disorders mentioned. In particular, ligands of G protein-coupled receptors (GPCRs), including metabotropic glutamatergic receptors (mGluRs), have been recognized as promising options for inhibiting excessive Glu transmission. This review discusses the complex interactions of mGlu receptors with their subtypes, including the formation of homo- and heterodimers, which may vary in function and pharmacology depending on their protomer composition. Understanding these intricate details of mGlu receptor structure and function enhances researchers' ability to develop targeted pharmacological interventions, potentially offering new therapeutic avenues for neurological and psychiatric disorders. This review also summarizes the current knowledge of the neuroprotective potential of ligands targeting group III mGluRs in preclinical cellular (in vitro) and animal (in vivo) models of ischemic stroke, TBI, PD, AD, and MS. In recent years, experiments have shown that compounds, especially those activating mGlu4 or mGlu7 receptors, exhibit protective effects in experimental ischemia models. The discovery of allosteric ligands for specific mGluR subtypes has led to reports suggesting that group III mGluRs may be promising targets for neuroprotective therapy in PD (mGlu4R), TBI (mGlu7R), and MS (mGlu8R).
Collapse
Affiliation(s)
- Helena Domin
- Maj Institute of Pharmacology, Department of Neurobiology, Polish Academy of Sciences, Smętna 12, Kraków, 31-343, Poland.
| | - Grzegorz Burnat
- Maj Institute of Pharmacology, Department of Neurobiology, Polish Academy of Sciences, Smętna 12, Kraków, 31-343, Poland
| |
Collapse
|
2
|
Sha Z, Xu J, Li N, Li O. Regulatory Molecules of Synaptic Plasticity in Anxiety Disorder. Int J Gen Med 2023; 16:2877-2886. [PMID: 37435365 PMCID: PMC10332425 DOI: 10.2147/ijgm.s413176] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 06/19/2023] [Indexed: 07/13/2023] Open
Abstract
Synaptic plasticity is the capacity of synaptic transmission between neurons to be strengthened or weakened. There are many signal molecules accumulated in the presynaptic and postsynaptic membranes that can lead to the regulation of synaptic plasticity and involvement in numerous of neurological and psychiatric diseases, including anxiety disorder. However, the regulatory mechanisms of synaptic plasticity in the development of anxiety disorder have not been well summarized. This review mainly aims to discuss the biological functions and mechanisms of synaptic plasticity-related molecules in anxiety disorder, with a particular focus on the metabotropic glutamate receptors, brain-derived neurotrophic factor, hyperpolarization-activated cyclic nucleotide-gated channels, and postsynaptic density 95. The summarized functions and mechanisms of synaptic plasticity-related molecules in anxiety will provide insight into novel neuroplasticity modifications for targeted therapy for anxiety.
Collapse
Affiliation(s)
- Zhongwei Sha
- Department of Mental Diseases, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Jian Xu
- Department of Mental Diseases, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Nana Li
- Department of Mental Diseases, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| | - Ou Li
- Department of Mental Diseases, Shanghai Municipal Hospital of Traditional Chinese Medicine, Shanghai University of Traditional Chinese Medicine, Shanghai, People’s Republic of China
| |
Collapse
|
3
|
Martín R, Suárez-Pinilla AS, García-Font N, Laguna-Luque ML, López-Ramos JC, Oset-Gasque MJ, Gruart A, Delgado-García JM, Torres M, Sánchez-Prieto J. The activation of mGluR4 rescues parallel fiber synaptic transmission and LTP, motor learning and social behavior in a mouse model of Fragile X Syndrome. Mol Autism 2023; 14:14. [PMID: 37029391 PMCID: PMC10082511 DOI: 10.1186/s13229-023-00547-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 04/03/2023] [Indexed: 04/09/2023] Open
Abstract
BACKGROUND Fragile X syndrome (FXS), the most common inherited intellectual disability, is caused by the loss of expression of the Fragile X Messenger Ribonucleoprotein (FMRP). FMRP is an RNA-binding protein that negatively regulates the expression of many postsynaptic as well as presynaptic proteins involved in action potential properties, calcium homeostasis and neurotransmitter release. FXS patients and mice lacking FMRP suffer from multiple behavioral alterations, including deficits in motor learning for which there is currently no specific treatment. METHODS We performed electron microscopy, whole-cell patch-clamp electrophysiology and behavioral experiments to characterise the synaptic mechanisms underlying the motor learning deficits observed in Fmr1KO mice and the therapeutic potential of positive allosteric modulator of mGluR4. RESULTS We found that enhanced synaptic vesicle docking of cerebellar parallel fiber to Purkinje cell Fmr1KO synapses was associated with enhanced asynchronous release, which not only prevents further potentiation, but it also compromises presynaptic parallel fiber long-term potentiation (PF-LTP) mediated by β adrenergic receptors. A reduction in extracellular Ca2+ concentration restored the readily releasable pool (RRP) size, basal synaptic transmission, β adrenergic receptor-mediated potentiation, and PF-LTP. Interestingly, VU 0155041, a selective positive allosteric modulator of mGluR4, also restored both the RRP size and PF-LTP in mice of either sex. Moreover, when injected into Fmr1KO male mice, VU 0155041 improved motor learning in skilled reaching, classical eyeblink conditioning and vestibuloocular reflex (VOR) tests, as well as the social behavior alterations of these mice. LIMITATIONS We cannot rule out that the activation of mGluR4s via systemic administration of VU0155041 can also affect other brain regions. Further studies are needed to stablish the effect of a specific activation of mGluR4 in cerebellar granule cells. CONCLUSIONS Our study shows that an increase in synaptic vesicles, SV, docking may cause the loss of PF-LTP and motor learning and social deficits of Fmr1KO mice and that the reversal of these changes by pharmacological activation of mGluR4 may offer therapeutic relief for motor learning and social deficits in FXS.
Collapse
Affiliation(s)
- Ricardo Martín
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain.
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain.
- Departamento de Fisiología, Facultad de Medicina, Universidad Complutense, 28040, Madrid, Spain.
| | - Alberto Samuel Suárez-Pinilla
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain
| | - Nuria García-Font
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain
- Centre for Discovery Brain Sciences and Simon Initiative for Developing Brain, University of Edinburgh, Edinburgh, EH89JZ, UK
| | | | - Juan C López-Ramos
- Division de Neurociencias, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | - María Jesús Oset-Gasque
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain
- Departamento de Bioquímica, Facultad de Farmacia, Universidad Complutense, Instituto Universitario Investigación en Neuroquímica, 28040, Madrid, Spain
| | - Agnes Gruart
- Division de Neurociencias, Universidad Pablo de Olavide, 41013, Sevilla, Spain
| | | | - Magdalena Torres
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain
| | - José Sánchez-Prieto
- Departamento de Bioquímica y Biología Molecular, Facultad de Veterinaria, Universidad Complutense, Instituto Universitario de Investigación en Neuroquímica, 28040, Madrid, Spain.
- Instituto de Investigación Sanitaria del Hospital Clínico San Carlos, 28040, Madrid, Spain.
| |
Collapse
|
4
|
Facilitating mGluR4 activity reverses the long-term deleterious consequences of chronic morphine exposure in male mice. Neuropsychopharmacology 2021; 46:1373-1385. [PMID: 33349673 PMCID: PMC8136479 DOI: 10.1038/s41386-020-00927-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 11/16/2020] [Accepted: 11/20/2020] [Indexed: 12/13/2022]
Abstract
Understanding the neurobiological underpinnings of abstinence from drugs of abuse is critical to allow better recovery and ensure relapse prevention in addicted subjects. By comparing the long-term transcriptional consequences of morphine and cocaine exposure, we identified the metabotropic glutamate receptor subtype 4 (mGluR4) as a promising pharmacological target in morphine abstinence. We evaluated the behavioral and molecular effects of facilitating mGluR4 activity in abstinent mice. Transcriptional regulation of marker genes of medium spiny neurons (MSNs) allowed best discriminating between 4-week morphine and cocaine abstinence in the nucleus accumbens (NAc). Among these markers, Grm4, encoding mGluR4, displayed down-regulated expression in the caudate putamen and NAc of morphine, but not cocaine, abstinent mice. Chronic administration of the mGluR4 positive allosteric modulator (PAM) VU0155041 (2.5 and 5 mg/kg) rescued social behavior, normalized stereotypies and anxiety and blunted locomotor sensitization in morphine abstinent mice. This treatment improved social preference but increased stereotypies in cocaine abstinent mice. Finally, the beneficial behavioral effects of VU0155041 treatment in morphine abstinent mice were correlated with restored expression of key MSN and neural activity marker genes in the NAc. This study reports that chronic administration of the mGluR4 PAM VU0155041 relieves long-term deleterious consequences of morphine exposure. It illustrates the neurobiological differences between opiate and psychostimulant abstinence and points to pharmacological repression of excessive activity of D2-MSNs in the NAc as a promising therapeutic lever in drug addiction.
Collapse
|
5
|
Gregory KJ, Goudet C. International Union of Basic and Clinical Pharmacology. CXI. Pharmacology, Signaling, and Physiology of Metabotropic Glutamate Receptors. Pharmacol Rev 2020; 73:521-569. [PMID: 33361406 DOI: 10.1124/pr.119.019133] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Metabotropic glutamate (mGlu) receptors respond to glutamate, the major excitatory neurotransmitter in the mammalian brain, mediating a modulatory role that is critical for higher-order brain functions such as learning and memory. Since the first mGlu receptor was cloned in 1992, eight subtypes have been identified along with many isoforms and splice variants. The mGlu receptors are transmembrane-spanning proteins belonging to the class C G protein-coupled receptor family and represent attractive targets for a multitude of central nervous system disorders. Concerted drug discovery efforts over the past three decades have yielded a wealth of pharmacological tools including subtype-selective agents that competitively block or mimic the actions of glutamate or act allosterically via distinct sites to enhance or inhibit receptor activity. Herein, we review the physiologic and pathophysiological roles for individual mGlu receptor subtypes including the pleiotropic nature of intracellular signal transduction arising from each. We provide a comprehensive analysis of the in vitro and in vivo pharmacological properties of prototypical and commercially available orthosteric agonists and antagonists as well as allosteric modulators, including ligands that have entered clinical trials. Finally, we highlight emerging areas of research that hold promise to facilitate rational design of highly selective mGlu receptor-targeting therapeutics in the future. SIGNIFICANCE STATEMENT: The metabotropic glutamate receptors are attractive therapeutic targets for a range of psychiatric and neurological disorders. Over the past three decades, intense discovery efforts have yielded diverse pharmacological tools acting either competitively or allosterically, which have enabled dissection of fundamental biological process modulated by metabotropic glutamate receptors and established proof of concept for many therapeutic indications. We review metabotropic glutamate receptor molecular pharmacology and highlight emerging areas that are offering new avenues to selectively modulate neurotransmission.
Collapse
Affiliation(s)
- Karen J Gregory
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (K.J.G.) and Institut de Génomique Fonctionnelle (IGF), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Sante et de la Recherche Medicale (INSERM), Montpellier, France (C.G.)
| | - Cyril Goudet
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences and Department of Pharmacology, Monash University, Parkville, Victoria, Australia (K.J.G.) and Institut de Génomique Fonctionnelle (IGF), University of Montpellier, Centre National de la Recherche Scientifique (CNRS), Institut National de la Sante et de la Recherche Medicale (INSERM), Montpellier, France (C.G.)
| |
Collapse
|
6
|
Glutamate receptors in domestication and modern human evolution. Neurosci Biobehav Rev 2020; 108:341-357. [DOI: 10.1016/j.neubiorev.2019.10.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 09/28/2019] [Accepted: 10/07/2019] [Indexed: 02/08/2023]
|
7
|
Zoicas I, Kornhuber J. The Role of Metabotropic Glutamate Receptors in Social Behavior in Rodents. Int J Mol Sci 2019; 20:ijms20061412. [PMID: 30897826 PMCID: PMC6470515 DOI: 10.3390/ijms20061412] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/15/2019] [Accepted: 03/20/2019] [Indexed: 01/04/2023] Open
Abstract
The appropriate display of social behavior is critical for the well-being and survival of an individual. In many psychiatric disorders, including social anxiety disorder, autism spectrum disorders, depression and schizophrenia social behavior is severely impaired. Selective targeting of metabotropic glutamate receptors (mGluRs) has emerged as a novel treatment strategy for these disorders. In this review, we describe some of the behavioral paradigms used to assess different types of social behavior, such as social interaction, social memory, aggressive behavior and sexual behavior. We then focus on the effects of pharmacological modulation of mGluR1-8 on these types of social behavior. Indeed, accumulating evidence indicates beneficial effects of selective ligands of specific mGluRs in ameliorating innate or pharmacologically-induced deficits in social interaction and social memory as well as in reducing aggression in rodents. We emphasize the importance of future studies investigating the role of selective mGluR ligands on different types of social behavior to provide a better understanding of the neural mechanisms involved which, in turn, might promote the development of selective mGluR-targeted tools for the improved treatment of psychiatric disorders associated with social deficits.
Collapse
Affiliation(s)
- Iulia Zoicas
- Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91054, Germany.
| | - Johannes Kornhuber
- Department of Psychiatry and Psychotherapy, University Hospital, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen 91054, Germany.
| |
Collapse
|
8
|
Jantas D, Grygier B, Zatorska J, Lasoń W. Allosteric and Orthosteric Activators of mGluR8 Differentially Affect the Chemotherapeutic-Induced Human Neuroblastoma SH-SY5Y Cell Damage: The Impact of Cell Differentiation State. Basic Clin Pharmacol Toxicol 2018; 123:443-451. [PMID: 29753314 DOI: 10.1111/bcpt.13041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/29/2018] [Indexed: 12/25/2022]
Abstract
The participation of group III metabotropic glutamate receptors (mGluRs) in cancer growth and progression is still an understudied issue. Based on our recent data on high expression of mGluR8 in human neuroblastoma SH-SY5Y cells, in this study, we evaluated the effect of an mGluR8-specific positive allosteric modulator (PAM: AZ12216052) and orthosteric agonist [(S)-3,4-DCPG ((S)-3,4-dicarboxyphenylglycine)] on chemotherapeutic (doxorubicin, irinotecan or cisplatin)-evoked cell damage in undifferentiated (UN-) and retinoic acid-differentiated (RA-) SH-SY5Y cells. The data showed that AZ12216052 as well as a group III mGluR antagonist (UBP1112) but not (S)-3,4-DCPG partially inhibited the cell damage evoked by doxorubicin, irinotecan or cisplatin in UN-SH-SY5Y cells. In RA-SH-SY5Y, we observed only a modest protective effect of mGluR8 PAM. In contrast, both types of mGluR8 activators significantly enhanced toxic effects of doxorubicin and irinotecan in RA-SH-SY5Y cells. These data suggest that in undifferentiated neuroblastoma malignant cells, some mGluR8 modulators can decrease cytotoxic effects of chemotherapeutics which exclude them from the group of putative anticancer agents. On the other hand, in SH-SY5Y cells differentiated to a more mature neuron-like phenotype, that is non-malignant cells, the mGluR8 activators can aggravate the chemotherapeutic neurotoxicity which is a well-known undesired effect of these drugs. Our pharmacological data add new observations to the unexplored field of research on the role of mGluR8 in cancer, pointing to complexity of response which could be mediated by particular types of mGluR8 ligands at least in neuroblastoma cells.
Collapse
Affiliation(s)
- Danuta Jantas
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Beata Grygier
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Justyna Zatorska
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| | - Władysław Lasoń
- Department of Experimental Neuroendocrinology, Institute of Pharmacology, Polish Academy of Sciences, Kraków, Poland
| |
Collapse
|
9
|
Ferraguti F. Metabotropic glutamate receptors as targets for novel anxiolytics. Curr Opin Pharmacol 2018; 38:37-42. [PMID: 29494817 DOI: 10.1016/j.coph.2018.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 02/12/2018] [Indexed: 12/12/2022]
Abstract
Anxiety disorders are highly prevalent psychiatric illnesses posing an important social and economic burden. Their current pharmacotherapy shows short term efficacy, though nearly one third of patients do not achieve sustained remission. There is, therefore, a strong medical need for new therapeutic agents acting through novel mechanisms of action. Considerable work has focused on metabotropic glutamate (mGlu) receptors as potential targets for novel anxiolytics. Ligands acting at mGlu receptors showed promising results in preclinical studies, whereas their efficacy was dubious in clinical trials. Recent preclinical and clinical studies have opened new prospects for targeting mGlu receptors to treat anxiety disorders. This review provides an outlook on these progresses.
Collapse
Affiliation(s)
- Francesco Ferraguti
- Department of Pharmacology, Medical University of Innsbruck, Peter Mayr Strasse 1A, 6020 Innsbruck, Austria.
| |
Collapse
|
10
|
Ryan NP, Catroppa C, Godfrey C, Noble-Haeusslein LJ, Shultz SR, O'Brien TJ, Anderson V, Semple BD. Social dysfunction after pediatric traumatic brain injury: A translational perspective. Neurosci Biobehav Rev 2016; 64:196-214. [PMID: 26949224 PMCID: PMC5627971 DOI: 10.1016/j.neubiorev.2016.02.020] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Revised: 02/24/2016] [Accepted: 02/24/2016] [Indexed: 12/21/2022]
Abstract
Social dysfunction is common after traumatic brain injury (TBI), contributing to reduced quality of life for survivors. Factors which influence the development or persistence of social deficits after injury remain poorly understood, particularly in the context of ongoing brain maturation during childhood and adolescence. Aberrant social interactions have recently been modeled in adult and juvenile rodents after experimental TBI, providing an opportunity to gain new insights into the underlying neurobiology of these behaviors. Here, we review our current understanding of social dysfunction in both humans and rodent models of TBI, with a focus on brain injuries acquired during early development. Modulators of social outcomes are discussed, including injury-related and environmental risk and resilience factors. Disruption of social brain network connectivity and aberrant neuroendocrine function are identified as potential mechanisms of social impairments after pediatric TBI. Throughout, we highlight the overlap and disparities between outcome measures and findings from clinical and experimental approaches, and explore the translational potential of future research to prevent or ameliorate social dysfunction after childhood TBI.
Collapse
Affiliation(s)
- Nicholas P Ryan
- Australian Centre for Child Neuropsychological Studies, Murdoch Childrens Research Institute, Parkville, VIC, Australia; Melbourne School of Psychological Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia.
| | - Cathy Catroppa
- Australian Centre for Child Neuropsychological Studies, Murdoch Childrens Research Institute, Parkville, VIC, Australia; Melbourne School of Psychological Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia; Department of Psychology, Royal Children's Hospital, Parkville, VIC, Australia.
| | - Celia Godfrey
- Australian Centre for Child Neuropsychological Studies, Murdoch Childrens Research Institute, Parkville, VIC, Australia.
| | - Linda J Noble-Haeusslein
- Departments of Neurological Surgery and Physical Therapy and Rehabilitation Science, University of California, San Francisco, San Francisco, CA, USA.
| | - Sandy R Shultz
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia.
| | - Terence J O'Brien
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia.
| | - Vicki Anderson
- Australian Centre for Child Neuropsychological Studies, Murdoch Childrens Research Institute, Parkville, VIC, Australia; Melbourne School of Psychological Sciences, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, VIC, Australia; Department of Psychology, Royal Children's Hospital, Parkville, VIC, Australia.
| | - Bridgette D Semple
- Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Parkville, VIC, Australia.
| |
Collapse
|
11
|
Peterlik D, Flor PJ, Uschold-Schmidt N. The Emerging Role of Metabotropic Glutamate Receptors in the Pathophysiology of Chronic Stress-Related Disorders. Curr Neuropharmacol 2016; 14:514-39. [PMID: 27296643 PMCID: PMC4983752 DOI: 10.2174/1570159x13666150515234920] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2015] [Revised: 04/04/2015] [Accepted: 05/12/2015] [Indexed: 12/28/2022] Open
Abstract
Chronic stress-related psychiatric conditions such as anxiety, depression, and alcohol abuse are an enormous public health concern. The etiology of these pathologies is complex, with psychosocial stressors being among the most frequently discussed risk factors. The brain glutamatergic neurotransmitter system has often been found involved in behaviors and pathophysiologies resulting from acute stress and fear. Despite this, relatively little is known about the role of glutamatergic system components in chronic psychosocial stress, neither in rodents nor in humans. Recently, drug discovery efforts at the metabotropic receptor subtypes of the glutamatergic system (mGlu1-8 receptors) led to the identification of pharmacological tools with emerging potential in psychiatric conditions. But again, the contribution of individual mGlu subtypes to the manifestation of physiological, molecular, and behavioral consequences of chronic psychosocial stress remains still largely unaddressed. The current review will describe animal models typically used to analyze acute and particularly chronic stress conditions, including models of psychosocial stress, and there we will discuss the emerging roles for mGlu receptor subtypes. Indeed, accumulating evidence indicates relevance and potential therapeutic usefulness of mGlu2/3 ligands and mGlu5 receptor antagonists in chronic stress-related disorders. In addition, a role for further mechanisms, e.g. mGlu7-selective compounds, is beginning to emerge. These mechanisms are important to be analyzed in chronic psychosocial stress paradigms, e.g. in the chronic subordinate colony housing (CSC) model. We summarize the early results and discuss necessary future investigations, especially for mGlu5 and mGlu7 receptor blockers, which might serve to suggest improved therapeutic strategies to treat stress-related disorders.
Collapse
Affiliation(s)
| | - Peter J Flor
- Faculty of Biology and Preclinical Medicine, University of Regensburg, D-93053 Regensburg, Germany.
| | - Nicole Uschold-Schmidt
- Faculty of Biology and Preclinical Medicine, University of Regensburg, D-93053 Regensburg, Germany.
| |
Collapse
|
12
|
Bondi CO, Semple BD, Noble-Haeusslein LJ, Osier ND, Carlson SW, Dixon CE, Giza CC, Kline AE. Found in translation: Understanding the biology and behavior of experimental traumatic brain injury. Neurosci Biobehav Rev 2015; 58:123-46. [PMID: 25496906 PMCID: PMC4465064 DOI: 10.1016/j.neubiorev.2014.12.004] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 10/26/2014] [Accepted: 12/02/2014] [Indexed: 12/14/2022]
Abstract
The aim of this review is to discuss in greater detail the topics covered in the recent symposium entitled "Traumatic brain injury: laboratory and clinical perspectives," presented at the 2014 International Behavioral Neuroscience Society annual meeting. Herein, we review contemporary laboratory models of traumatic brain injury (TBI) including common assays for sensorimotor and cognitive behavior. New modalities to evaluate social behavior after injury to the developing brain, as well as the attentional set-shifting test (AST) as a measure of executive function in TBI, will be highlighted. Environmental enrichment (EE) will be discussed as a preclinical model of neurorehabilitation, and finally, an evidence-based approach to sports-related concussion will be considered. The review consists predominantly of published data, but some discussion of ongoing or future directions is provided.
Collapse
Affiliation(s)
- Corina O Bondi
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States; Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States
| | - Bridgette D Semple
- Neurological Surgery and the Graduate Program in Physical Medicine & Rehabilitation Science, University of California, San Francisco, San Francisco, CA, United States; Department of Medicine (Royal Melbourne Hospital), University of Melbourne, Parkville, VIC, Australia
| | - Linda J Noble-Haeusslein
- Neurological Surgery and the Graduate Program in Physical Medicine & Rehabilitation Science, University of California, San Francisco, San Francisco, CA, United States
| | - Nicole D Osier
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States; School of Nursing, University of Pittsburgh, Pittsburgh, PA, United States
| | - Shaun W Carlson
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States; Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, United States
| | - C Edward Dixon
- Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States; Neurological Surgery, University of Pittsburgh, Pittsburgh, PA, United States; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, PA, United States
| | - Christopher C Giza
- Pediatric Neurology and Neurosurgery, University of California, Los Angeles, Los Angeles, CA, United States; UCLA Brain Injury Research Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States
| | - Anthony E Kline
- Physical Medicine & Rehabilitation, University of Pittsburgh, Pittsburgh, PA, United States; Safar Center for Resuscitation Research, University of Pittsburgh, Pittsburgh, PA, United States; Center for Neuroscience, University of Pittsburgh, Pittsburgh, PA, United States; Center for the Neural Basis of Cognition, University of Pittsburgh, Pittsburgh, PA, United States; Psychology, University of Pittsburgh, Pittsburgh, PA, United States; Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, United States.
| |
Collapse
|
13
|
Therapeutic potential of group III metabotropic glutamate receptor ligands in pain. Curr Opin Pharmacol 2015; 20:64-72. [DOI: 10.1016/j.coph.2014.11.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Revised: 11/18/2014] [Accepted: 11/21/2014] [Indexed: 11/22/2022]
|
14
|
Raber J, Duvoisin RM. Novel metabotropic glutamate receptor 4 and glutamate receptor 8 therapeutics for the treatment of anxiety. Expert Opin Investig Drugs 2014; 24:519-28. [DOI: 10.1517/13543784.2014.986264] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Jacob Raber
- 1Departments of Behavioral Neuroscience, Neurology, and Radiation Medicine, Oregon Health and Science University, Division of Neuroscience, ONPRC, Portland, OR, USA ;
| | - Robert M Duvoisin
- 2Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, OR, USA
| |
Collapse
|
15
|
Mercier MS, Lodge D. Group III metabotropic glutamate receptors: pharmacology, physiology and therapeutic potential. Neurochem Res 2014; 39:1876-94. [PMID: 25146900 DOI: 10.1007/s11064-014-1415-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Revised: 08/08/2014] [Accepted: 08/11/2014] [Indexed: 01/14/2023]
Abstract
Glutamate, the primary excitatory neurotransmitter in the central nervous system (CNS), exerts neuromodulatory actions via the activation of metabotropic glutamate (mGlu) receptors. There are eight known mGlu receptor subtypes (mGlu1-8), which are widely expressed throughout the brain, and are divided into three groups (I-III), based on signalling pathways and pharmacological profiles. Group III mGlu receptors (mGlu4/6/7/8) are primarily, although not exclusively, localised on presynaptic terminals, where they act as both auto- and hetero-receptors, inhibiting the release of neurotransmitter. Until recently, our understanding of the role of individual group III mGlu receptor subtypes was hindered by a lack of subtype-selective pharmacological tools. Recent advances in the development of both orthosteric and allosteric group III-targeting compounds, however, have prompted detailed investigations into the possible functional role of these receptors within the CNS, and revealed their involvement in a number of pathological conditions, such as epilepsy, anxiety and Parkinson's disease. The heterogeneous expression of group III mGlu receptor subtypes throughout the brain, as well as their distinct distribution at glutamatergic and GABAergic synapses, makes them ideal targets for therapeutic intervention. This review summarises the advances in subtype-selective pharmacology, and discusses the individual roles of group III mGlu receptors in physiology, and their potential involvement in disease.
Collapse
Affiliation(s)
- Marion S Mercier
- Centre for Synaptic Plasticity, School of Physiology and Pharmacology, Dorothy Hodgkin Building, University of Bristol, Bristol, BS1 3NY, UK,
| | | |
Collapse
|
16
|
Semple BD, Noble-Haeusslein LJ, Jun Kwon Y, Sam PN, Gibson AM, Grissom S, Brown S, Adahman Z, Hollingsworth CA, Kwakye A, Gimlin K, Wilde EA, Hanten G, Levin HS, Schenk AK. Sociosexual and communication deficits after traumatic injury to the developing murine brain. PLoS One 2014; 9:e103386. [PMID: 25106033 PMCID: PMC4126664 DOI: 10.1371/journal.pone.0103386] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2014] [Accepted: 06/10/2014] [Indexed: 12/19/2022] Open
Abstract
Despite the life-long implications of social and communication dysfunction after pediatric traumatic brain injury, there is a poor understanding of these deficits in terms of their developmental trajectory and underlying mechanisms. In a well-characterized murine model of pediatric brain injury, we recently demonstrated that pronounced deficits in social interactions emerge across maturation to adulthood after injury at postnatal day (p) 21, approximating a toddler-aged child. Extending these findings, we here hypothesized that these social deficits are dependent upon brain maturation at the time of injury, and coincide with abnormal sociosexual behaviors and communication. Age-dependent vulnerability of the developing brain to social deficits was addressed by comparing behavioral and neuroanatomical outcomes in mice injured at either a pediatric age (p21) or during adolescence (p35). Sociosexual behaviors including social investigation and mounting were evaluated in a resident-intruder paradigm at adulthood. These outcomes were complemented by assays of urine scent marking and ultrasonic vocalizations as indices of social communication. We provide evidence of sociosexual deficits after brain injury at p21, which manifest as reduced mounting behavior and scent marking towards an unfamiliar female at adulthood. In contrast, with the exception of the loss of social recognition in a three-chamber social approach task, mice that received TBI at adolescence were remarkably resilient to social deficits at adulthood. Increased emission of ultrasonic vocalizations (USVs) as well as preferential emission of high frequency USVs after injury was dependent upon both the stimulus and prior social experience. Contrary to the hypothesis that changes in white matter volume may underlie social dysfunction, injury at both p21 and p35 resulted in a similar degree of atrophy of the corpus callosum by adulthood. However, loss of hippocampal tissue was greater after p21 compared to p35 injury, suggesting that a longer period of lesion progression or differences in the kinetics of secondary pathogenesis after p21 injury may contribute to observed behavioral differences. Together, these findings indicate vulnerability of the developing brain to social dysfunction, and suggest that a younger age-at-insult results in poorer social and sociosexual outcomes.
Collapse
Affiliation(s)
- Bridgette D. Semple
- Department of Neurological Surgery, University of California San Francisco, San Francisco, California, United States of America
- Department of Medicine (Royal Melbourne Hospital), Melbourne Brain Centre, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
| | - Linda J. Noble-Haeusslein
- Department of Neurological Surgery, University of California San Francisco, San Francisco, California, United States of America
- Department of Physical Therapy and Rehabilitation, University of California San Francisco, San Francisco, California, United States of America
| | - Yong Jun Kwon
- Department of Physics, Randolph College, Lynchburg, Virginia, United States of America
| | - Pingdewinde N. Sam
- Department of Neurological Surgery, University of California San Francisco, San Francisco, California, United States of America
- San Francisco State University, San Francisco, California, United States of America
| | - A. Matt Gibson
- Department of Physics, Randolph College, Lynchburg, Virginia, United States of America
| | - Sarah Grissom
- Department of Physics, Randolph College, Lynchburg, Virginia, United States of America
| | - Sienna Brown
- Department of Physics, Randolph College, Lynchburg, Virginia, United States of America
| | - Zahra Adahman
- Department of Physics, Randolph College, Lynchburg, Virginia, United States of America
| | | | - Alexander Kwakye
- Department of Physics, Randolph College, Lynchburg, Virginia, United States of America
| | - Kayleen Gimlin
- Department of Neurological Surgery, University of California San Francisco, San Francisco, California, United States of America
| | - Elisabeth A. Wilde
- Physical Medicine and Rehabilitation Alliance of Baylor College of Medicine and the University of Texas-Houston Medical School, Houston, Texas, United States of America
- Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas, United States of America
| | - Gerri Hanten
- Physical Medicine and Rehabilitation Alliance of Baylor College of Medicine and the University of Texas-Houston Medical School, Houston, Texas, United States of America
| | - Harvey S. Levin
- Physical Medicine and Rehabilitation Alliance of Baylor College of Medicine and the University of Texas-Houston Medical School, Houston, Texas, United States of America
- Michael E. DeBakey Veterans Affairs Medical Center, Houston, Texas, United States of America
| | - A. Katrin Schenk
- Department of Physics, Randolph College, Lynchburg, Virginia, United States of America
| |
Collapse
|
17
|
Autistic-like syndrome in mu opioid receptor null mice is relieved by facilitated mGluR4 activity. Neuropsychopharmacology 2014; 39:2049-60. [PMID: 24619243 PMCID: PMC4104328 DOI: 10.1038/npp.2014.59] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 02/28/2014] [Accepted: 02/28/2014] [Indexed: 02/03/2023]
Abstract
The etiology of Autism Spectrum Disorders (ASDs) remains largely unknown. Identifying vulnerability genes for autism represents a major challenge in the field and allows the development of animal models for translational research. Mice lacking the mu opioid receptor gene (Oprm1(-/-)) were recently proposed as a monogenic mouse model of autism, based on severe deficits in social behavior and communication skills. We confirm this hypothesis by showing that adult Oprm1(-/-) animals recapitulate core and multiple comorbid behavioral symptoms of autism and also display anatomical, neurochemical, and genetic landmarks of the disease. Chronic facilitation of mGluR4 signaling, which we identified as a novel pharmacological target in ASDs in these mice, was more efficient in alleviating behavioral deficits than the reference molecule risperidone. Altogether, our data provide first evidence that disrupted mu opioid receptor signaling is sufficient to trigger a comprehensive autistic syndrome, maybe through blunted social reward processes, and this mouse model opens promising avenues for therapeutic innovation.
Collapse
|
18
|
Kalinichev M, Le Poul E, Boléa C, Girard F, Campo B, Fonsi M, Royer-Urios I, Browne SE, Uslaner JM, Davis MJ, Raber J, Duvoisin R, Bate ST, Reynolds IJ, Poli S, Celanire S. Characterization of the novel positive allosteric modulator of the metabotropic glutamate receptor 4 ADX88178 in rodent models of neuropsychiatric disorders. J Pharmacol Exp Ther 2014; 350:495-505. [PMID: 24947466 DOI: 10.1124/jpet.114.214437] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
There is growing evidence that activation of metabotropic glutamate receptor 4 (mGlu4) leads to anxiolytic- and antipsychotic-like efficacy in rodent models, yet its relevance to depression-like reactivity remains unclear. Here, we present the pharmacological evaluation of ADX88178 [5-methyl-N-(4-methylpyrimidin-2-yl)-4-(1H-pyrazol-4-yl)thiazol-2-amine], a novel potent, selective, and brain-penetrant positive allosteric modulator of the mGlu4 receptor in rodent models of anxiety, obsessive compulsive disorder (OCD), fear, depression, and psychosis. ADX88178 dose-dependently reduced the number of buried marbles in the marble burying test and increased open-arm exploration in the elevated plus maze (EPM) test, indicative of anxiolytic-like efficacy. Target specificity of the effect in the EPM test was confirmed using male and female mGlu4 receptor knockout mice. In mice, ADX88178 reduced the likelihood of conditioned freezing in the acquisition phase of the fear conditioning test, yet had no carryover effect in the expression phase. Also, ADX88178 dose-dependently reduced duration of immobility in the forced swim test, indicative of antidepressant-like efficacy. ADX88178 reduced DOI (2,5-dimethoxy-4-iodoamphetamine)-mediated head twitches (albeit with no dose-dependency), and MK-801 [(5S,10R)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine]-induced locomotor hyperactivity in mice, but was inactive in the conditioned avoidance response test in rats. The compound showed good specificity as it had no effect on locomotor activity in mice and rats at efficacious doses. Thus, allosteric activation of mGlu4 receptors can be a promising new therapeutic approach for treatment of anxiety, OCD, fear-related disorders, and psychosis.
Collapse
Affiliation(s)
- Mikhail Kalinichev
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Emmanuel Le Poul
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Christelle Boléa
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Françoise Girard
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Brice Campo
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Massimiliano Fonsi
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Isabelle Royer-Urios
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Susan E Browne
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Jason M Uslaner
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Matthew J Davis
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Jacob Raber
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Robert Duvoisin
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Simon T Bate
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Ian J Reynolds
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Sonia Poli
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| | - Sylvain Celanire
- Addex Therapeutics, Plan-les-Ouates, Geneva, Switzerland (M.K., E.L.P., C.B., F.G., B.C., M.F., I.R.-U., S.P., S.C.); Merck Research Laboratories, West Point, Pennsylvania (S.E.B., J.M.U., M.J.D., I.J.R.); Oregon Health & Science University, Portland, Oregon (M.J.D., J.R., R.D.); and Huntingdon Life Sciences Ltd., Huntingdon Research Centre, Huntingdon, United Kingdom (S.T.B.)
| |
Collapse
|
19
|
Pomierny-Chamioło L, Rup K, Pomierny B, Niedzielska E, Kalivas PW, Filip M. Metabotropic glutamatergic receptors and their ligands in drug addiction. Pharmacol Ther 2014; 142:281-305. [DOI: 10.1016/j.pharmthera.2013.12.012] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Accepted: 12/02/2013] [Indexed: 02/07/2023]
|
20
|
Yin S, Niswender CM. Progress toward advanced understanding of metabotropic glutamate receptors: structure, signaling and therapeutic indications. Cell Signal 2014; 26:2284-97. [PMID: 24793301 DOI: 10.1016/j.cellsig.2014.04.022] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2014] [Accepted: 04/27/2014] [Indexed: 12/24/2022]
Abstract
The metabotropic glutamate (mGlu) receptors are a group of Class C seven-transmembrane spanning/G protein-coupled receptors (7TMRs/GPCRs). These receptors are activated by glutamate, one of the standard amino acids and the major excitatory neurotransmitter. By activating G protein-dependent and non-G protein-dependent signaling pathways, mGlus modulate glutamatergic transmission both in the periphery and throughout the central nervous system. Since the discovery of the first mGlu receptor, and especially during the last decade, a great deal of progress has been made in understanding the signaling, structure, pharmacological manipulation and therapeutic indications of the 8 mGlu members.
Collapse
Affiliation(s)
- Shen Yin
- Department of Pharmacology, Vanderbilt University Medical School, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical School, Nashville, TN 37232, USA
| | - Colleen M Niswender
- Department of Pharmacology, Vanderbilt University Medical School, Nashville, TN 37232, USA; Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University Medical School, Nashville, TN 37232, USA.
| |
Collapse
|
21
|
Engers DW, Lindsley CW. Allosteric modulation of Class C GPCRs: a novel approach for the treatment of CNS disorders. DRUG DISCOVERY TODAY. TECHNOLOGIES 2014; 10:e269-76. [PMID: 24050278 DOI: 10.1016/j.ddtec.2012.10.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Allosteric modulation has emerged as an innovative pharmacological approach to selectively activate or inhibit several Class C GPCRs. Of the Class C GPCRs, metabotropic glutamate (mGlu) receptors represent the most promising candidates for clinical success, and both positive allosteric modulators (PAMs) and negative allosteric modulators (NAMs) of mGluRs have demonstrated therapeutic potential for a range of psychiatric and neurological disorders such as pain, depression, anxiety, cognition, Fragile X syndrome, Parkinson’s disease and schizophrenia.
Collapse
|
22
|
Palazzo E, de Novellis V, Rossi F, Maione S. Supraspinal metabotropic glutamate receptor subtype 8: a switch to turn off pain. Amino Acids 2014; 46:1441-8. [PMID: 24623118 DOI: 10.1007/s00726-014-1703-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Accepted: 02/18/2014] [Indexed: 12/28/2022]
Abstract
Glutamate is the main excitatory neurotransmitter in the central nervous system and as such controls the majority of synapses. Glutamatergic neurotransmission is mediated via ionotropic and metabotropic glutamate receptors (iGluRs and mGluRs). Signaling via mGluRs permits to finely tune, rather than turning on/off, the excitatory neurotransmission as the iGluRs do. Eight mGluRs (mGluR1-8) have been cloned so far, which have been divided into three groups based on sequence homology, pharmacological properties and second messenger signaling. mGluRs are widely expressed both on glia and neurons. On neurons they are located both at postsynaptic (group I) and presynaptic sites (group II and III). Group II and III mGluR stimulation reduces glutamate release, which can prove useful in pathological conditions characterized by elevated glutamatergic neurotransmission which include chronic pain. Indeed, mGluRs are widely distributed on pain neuraxis. The recent development of selective mGluR ligands has permitted investigating the individual role of each mGluR on pain control. The development of (S)-3,4-dicarboxyphenylglycine, a selective mGluR8 agonist, has revealed the mGluR8 role in inhibiting pain and its related affective consequences in chronic pain conditions. mGluR8 proved also to be overexpressed in pain controlling areas during pathological pain guaranteeing the availability of a switch for turning off abnormal pain. Thus, mGluR8 corresponds to an ideal target in designing novel analgesics. This review will focus on the novel insights into the mGluR8 role on pain control, with particular emphasis on the supraspinal descending pathway, an antinociceptive endogenous source, whose activation or disinhibition (via mGluR8) induces analgesia.
Collapse
Affiliation(s)
- Enza Palazzo
- Department of Anaesthesiology, Surgery and Emergency, The Second University of Naples, Piazza Luigi Miraglia 2, 80138, Naples, Italy,
| | | | | | | |
Collapse
|
23
|
Williams CJ, Dexter DT. Neuroprotective and symptomatic effects of targeting group III mGlu receptors in neurodegenerative disease. J Neurochem 2013; 129:4-20. [PMID: 24224472 DOI: 10.1111/jnc.12608] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2013] [Revised: 10/28/2013] [Accepted: 11/06/2013] [Indexed: 12/21/2022]
Abstract
Neurodegenerative disorders possess common pathological mechanisms, such as protein aggregation, inflammation, oxidative stress (OS) and excitotoxicity, raising the possibility of shared therapeutic targets. As a result of the selective cellular and regional expression of group III metabotropic glutamate (mGlu) receptors, drugs targeting such receptors have demonstrated both neuroprotective properties and symptomatic improvements in several models of neurodegeneration. In recent years, the discovery and development of subtype-selective ligands for the group III mGlu receptors has gained pace, allowing further research into the functions of these receptors and revealing their roles in health and disease. Activation of this class of receptors results in neuroprotection, with a variety of underlying mechanisms implicated. Group III mGlu receptor stimulation prevents excitotoxicity by inhibiting glutamate release from neurons and microglia and increasing glutamate uptake by astrocytes. It also attenuates the neuroinflammatory response by reducing glial reactivity and encourages neurotrophic phenotypes. This article will review the current literature with regard to the neuroprotective and symptomatic effects of group III mGlu receptor activation and discuss their promise as therapeutic targets in neurodegenerative disease. We review the neuroprotective and symptomatic effects of targeting group III mGlu receptors in neurodegenerative disease: Excess extracellular glutamate causes overactivation of NMDA receptors resulting in excitotoxicity. Externalization of phosphatidylserine stimulates phagocytosis of neurons by activated microglia, which contribute to damage through glutamate and pro-inflammatory factor release. Reactive astrocytes produce cytotoxic factors enhancing neuronal cell death. Activation of group III mGlu receptors by glutamate and/or mGlu receptor ligands results in inhibition of glutamate release from presynaptic terminals and microglia, reducing excitotoxicity. Astrocytic glutamate uptake is increased and microglia produce neurotrophic factors.
Collapse
Affiliation(s)
- Claire J Williams
- Parkinson's Disease Research Group, Centre for Neuroinflammation and Neurodegeneration, Division of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, London, UK
| | | |
Collapse
|
24
|
Chen CY, Noble-Haeusslein LJ, Ferriero D, Semple BD. Traumatic injury to the immature frontal lobe: a new murine model of long-term motor impairment in the absence of psychosocial or cognitive deficits. Dev Neurosci 2013; 35:474-90. [PMID: 24247103 DOI: 10.1159/000355874] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2013] [Accepted: 09/20/2013] [Indexed: 11/19/2022] Open
Abstract
Traumatic brain injury in children commonly involves the frontal lobes and is associated with distinct structural and behavioral changes. Despite the clinical significance of injuries localized to this region during brain development, the mechanisms underlying secondary damage and long-term recovery are poorly understood. Here, we have characterized the first model of unilateral focal traumatic injury to the developing frontal lobe. Male C57Bl/6J mice at postnatal day (p)21, an age approximating a toddler-aged child, received a controlled cortical impact or sham surgery to the left frontal lobe and were euthanized 1 or 7 days later. A necrotic cavity and local inflammatory response were largely confined to the unilateral frontal lobe, dorsal corpus callosum and striatum anterior to the bregma. While cell death and accumulated β-amyloid precursor protein were characteristic features of the pericontusional motor cortex, corpus callosum, cingulum and dorsal striatum, underlying structures including the hippocampus showed no overt pathology. To determine the long-term functional consequences of injury at p21, two additional cohorts were subjected to a battery of behavioral tests in adolescence (p35-45) or adulthood (p70-80). In both cohorts, brain-injured mice showed normal levels of anxiety, sociability, spatial learning and memory. The signature phenotypic features were deficits in motor function and motor learning, coincident with a reduction in ipsilateral cortical brain volumes. Together, these findings demonstrate classic morphological features of a focal traumatic injury, including early cell death and axonal injury, and long-term volumetric loss of cortical volumes. The presence of deficits in sensorimotor function and coordination in the absence of abnormal findings related to anxiety, sociability and memory likely reflects several variables, including the unique location of the injury and the emergence of favorable compensatory mechanisms during subsequent brain development.
Collapse
Affiliation(s)
- Chien-Yi Chen
- Department of Neurological Surgery,University of California, San Francisco, San Francisco, Calif., USA
| | | | | | | |
Collapse
|
25
|
Griebel G, Holmes A. 50 years of hurdles and hope in anxiolytic drug discovery. Nat Rev Drug Discov 2013; 12:667-87. [PMID: 23989795 DOI: 10.1038/nrd4075] [Citation(s) in RCA: 295] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Anxiety disorders are the most prevalent group of psychiatric diseases, and have high personal and societal costs. The search for novel pharmacological treatments for these conditions is driven by the growing medical need to improve on the effectiveness and the side effect profile of existing drugs. A huge volume of data has been generated by anxiolytic drug discovery studies, which has led to the progression of numerous new molecules into clinical trials. However, the clinical outcome of these efforts has been disappointing, as promising results with novel agents in rodent studies have very rarely translated into effectiveness in humans. Here, we analyse the major trends from preclinical studies over the past 50 years conducted in the search for new drugs beyond those that target the prototypical anxiety-associated GABA (γ-aminobutyric acid)-benzodiazepine system, which have focused most intensively on the serotonin, neuropeptide, glutamate and endocannabinoid systems. We highlight various key issues that may have hampered progress in the field, and offer recommendations for how anxiolytic drug discovery can be more effective in the future.
Collapse
Affiliation(s)
- Guy Griebel
- Sanofi, Exploratory Unit, Chilly-Mazarin 91385, France
| | | |
Collapse
|
26
|
Effects of group II and III metabotropic glutamate receptor ligands on conditioned taste aversion learning. Behav Brain Res 2013; 253:9-16. [DOI: 10.1016/j.bbr.2013.06.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2013] [Revised: 06/22/2013] [Accepted: 06/27/2013] [Indexed: 12/13/2022]
|
27
|
Davis MJ, Duvoisin RM, Raber J. Related functions of mGlu4 and mGlu8. Pharmacol Biochem Behav 2013; 111:11-6. [PMID: 23948069 DOI: 10.1016/j.pbb.2013.07.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2013] [Revised: 07/25/2013] [Accepted: 07/31/2013] [Indexed: 11/15/2022]
Abstract
Metabotropic glutamate receptors modulate glutamatergic and GABAergic neurotransmission. Our previous pharmacological data indicate that metabotropic receptor 4 (mGlu4) and metabotropic receptor 8 (mGlu8) might have related and overlapping functions. We explored this by analyzing the behavioral phenotypes of mice deficient in either (mGlu4(-/-) or mGlu8(-/-)) or both receptors (mGlu4/8(-/-)). Our analysis focused on measures of anxiety in the open field and elevated zero maze, sensorimotor function on the rotarod and fear conditioning, as mGlu4 and/or mGlu8 were shown to affect performance in these tests. mGlu8(-/-) mice weighed more than mGlu4/8(-/-) mice. In the open field, mGlu4(-/-) mice showed lower levels of anxiety than mGlu8(-/-) and mGlu4/8(-/-) mice. In the elevated zero maze, mGlu4(-/-) mice showed lower levels of anxiety than wild-type, mGlu8(-/-) and mGlu4/8(-/-) mice. In the open field, but not elevated zero maze, mGlu4(-/-) mice showed lower activity levels than wild-type, mGlu8(-/-) and mGlu4/8(-/-) mice. mGlu4/8(-/-) female mice showed less contextual freezing than wild-type and mGlu4(-/-) female mice and there was a trend toward less freezing in male mGlu4/8(-/-) than wild-type male mice. There were no genotype differences in cued fear conditioning. There were significant negative correlations between body weight and fall latency on the rotarod in wild-type, mGlu8(-/-) and mGlu4/8(-/-), but not mGlu4(-/-), mice. These data suggest related functions of mGlu4 and mGlu8 in behavioral performance.
Collapse
Affiliation(s)
- Matthew J Davis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
| | | | | |
Collapse
|
28
|
Semple BD, Canchola SA, Noble-Haeusslein LJ. Deficits in social behavior emerge during development after pediatric traumatic brain injury in mice. J Neurotrauma 2012; 29:2672-83. [PMID: 22888909 PMCID: PMC3510450 DOI: 10.1089/neu.2012.2595] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The pediatric brain may be particularly vulnerable to social deficits after traumatic brain injury (TBI) due to the protracted nature of psychosocial development through adolescence. However, the majority of pre-clinical studies fail to assess social outcomes in experimental pediatric TBI. The current study evaluated social behavior in mice subjected to TBI at post-natal day (p)21. Social behaviors were assessed by a partition test, resident-intruder, three-chamber, and tube dominance tasks during adolescence (p35-42) and again during early adulthood (p60-70), during encounters with unfamiliar, naïve stimulus mice. Despite normal olfactory function and normal social behaviors during adolescence, brain-injured mice showed impaired social investigation by adulthood, evidenced by reduced ano-genital sniffing and reduced following of stimulus mice in the resident-intruder task, as well as a loss of preference for sociability in the three-chamber task. TBI mice also lacked a preference for social novelty, suggestive of a deficit in social recognition or memory. By adulthood, brain-injured mice exerted more frequent dominance in the tube task compared to sham-operated controls, a finding suggestive of aggressive tendencies. Together these findings reveal reduced social interaction and a tendency towards increased aggression, which evolves across development to adulthood. This emergence of aberrant social behavior, which parallels the development of other cognitive deficits in this model and behaviors seen in brain-injured children, is consistent with the hypothesis that the full extent of deficits is not realized until the associated skills reach maturity. Thus, efficacy of therapeutics for pediatric TBI should take into account the time-dependent emergence of abnormal behavioral patterns.
Collapse
Affiliation(s)
- Bridgette D Semple
- Department of Neurological Surgery, University of California San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143-0112, USA.
| | | | | |
Collapse
|
29
|
Sławińska A, Wierońska JM, Stachowicz K, Pałucha-Poniewiera A, Uberti MA, Bacolod MA, Doller D, Pilc A. Anxiolytic- but not antidepressant-like activity of Lu AF21934, a novel, selective positive allosteric modulator of the mGlu₄ receptor. Neuropharmacology 2012; 66:225-35. [PMID: 22634361 DOI: 10.1016/j.neuropharm.2012.05.001] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 04/19/2012] [Accepted: 05/02/2012] [Indexed: 11/18/2022]
Abstract
Previous studies demonstrated that the Group III mGlu receptor-selective orthosteric agonist, LSP1-2111 produced anxiolytic- but not antidepressant-like effects upon peripheral administration. Herein, we report the pharmacological actions of Lu AF21934, a novel, selective, and brain-penetrant positive allosteric modulator (PAM) of the mGlu(4) receptor in the stress-induced hyperthermia (SIH), four-plate, marble-burying and Vogel's conflict tests. In all models, except Vogel's conflict test, a dose-dependent anxiolytic-like effect was seen. The anti-hyperthermic effect of Lu AF21934 (5 mg/kg) in the SIH test was inhibited by the benzodiazepine receptor antagonist flumazenil (10 mg/kg) and was not serotonin-dependent, as it persisted in serotonin-deficient mice and upon blockade of either 5-HT(1A) receptors by WAY100635, or 5-HT(2A/2C) receptors by ritanserin. These results suggest that the GABAergic system, but not the serotonergic system, is involved in the mechanism of the anxiolytic-like phenotype of Lu AF21934 in rodents. Lu AF21934 did not produce antidepressant-like effects in the tail suspension test (TST) in mice; however, it decreased the basal locomotor activity of mice that were not habituated to activity cages. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
Collapse
Affiliation(s)
- Anna Sławińska
- Institute of Pharmacology, Polish Academy of Sciences, 31-343 Kraków, Poland
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Flor PJ, Acher FC. Orthosteric versus allosteric GPCR activation: the great challenge of group-III mGluRs. Biochem Pharmacol 2012; 84:414-24. [PMID: 22554564 DOI: 10.1016/j.bcp.2012.04.013] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Revised: 04/17/2012] [Accepted: 04/17/2012] [Indexed: 10/28/2022]
Abstract
Group-III metabotropic glutamate receptors (mGluRs) comprise four structurally related brain and retinal G protein-coupled receptors (GPCRs), mGluR4, mGluR6, mGluR7 and mGluR8, which receive much attention as promising targets for nervous system drugs. In particular, activation of mGluR4 is a major focus for the development of new therapeutics in Parkinson's disease, while mGluR7 activation is considered a potential approach for future treatments of specific psychiatric conditions. The first generation group-III mGluR agonists, e.g.l-AP4 and l-SOP, are characterized by an essential phosphonate functional group, which became a major limitation for the development of systemically active, potent and receptor subtype-selective drugs. Recently however, two approaches emerged in parallel providing resolution to this constraint: in silico high-throughput screening of chemical libraries against a 3D-model of the mGluR4 extracellular domain identified a hit that was optimized into a series of potent and subtype-selective orthosteric agonists with drug-like properties and novel chemotype structures; secondly, high-throughput random screening of chemical libraries against recombinantly expressed group-III receptors identified diverse chemical sets of allosteric agonists and positive modulators, which are drug-like, display selectivity for mGluR4, mGluR7, or mGluR8 and act via novel pharmacological sites. Here, we illustrate new scientific insights obtained via the use of those strategies. Also, we compare advantages and disadvantages of both approaches to identify the desired group-III mGluR activators and we conclude with suggestions how to employ those discovery strategies with success for the identification, optimization, and development of clinical drug candidates; this may have important implications for the entire field of GPCR research.
Collapse
Affiliation(s)
- Peter J Flor
- Faculty of Biology and Preclinical Medicine, University of Regensburg, Regensburg, Germany.
| | | |
Collapse
|
31
|
Davis MJ, Haley T, Duvoisin RM, Raber J. Measures of anxiety, sensorimotor function, and memory in male and female mGluR4⁻/⁻ mice. Behav Brain Res 2012; 229:21-8. [PMID: 22227508 DOI: 10.1016/j.bbr.2011.12.037] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Revised: 12/21/2011] [Accepted: 12/22/2011] [Indexed: 11/15/2022]
Abstract
Metabotropic glutamate receptors (mGluRs) are coupled to second messenger pathways via G proteins and modulate synaptic transmission. Of the eight different types of mGluRs (mGluR1-mGluR8), mGluR4, mGluR6, mGluR7, and mGluR8 are members of group III. Group III receptors are generally located presynaptically, where they regulate neurotransmitter release. Because of their role in modulating neurotransmission, mGluRs are attractive targets for therapies aimed at treating anxiety disorders. Previously we showed that the mGluR4-selective allosteric agonist VU 0155041 reduces anxiety-like behavior in wild-type male mice. Here, we explore the role of mGluR4 in adult (6-month old) and middle-aged (12-month old) male and female mice lacking this receptor. Compared to age- and sex-matched wild-type mice, middle-aged mGluR4(-/-) male mice showed increased measures of anxiety in the open field and elevated zero maze and impaired sensorimotor function on the rotarod. These changes were not seen in adult 6-month-old male mice. In contrast to the male mice, mGluR4(-/-) female mice showed reduced measures of anxiety in the open field and elevated zero maze and enhanced rotarod performance. During the hidden platform training sessions of the water maze, mGluR4(-/-) mice swam farther away from the platform than wild-type mice at 6, but not at 12, months of age. mGluR4(-/-) mice also showed enhanced amygdala-dependent cued fear conditioning. No genotype differences were seen in hippocampus-dependent contextual fear conditioning. These data indicate that effects of mGluR4 on sensorimotor function and measures of anxiety, but not cued fear conditioning, are critically modulated by sex and age.
Collapse
Affiliation(s)
- Matthew J Davis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR 97239, USA
| | | | | | | |
Collapse
|