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Zhang P, Wei J, Zhaoshun L, Xingxuan L, Li L. Study on the Mechanism of Gut Microbiota in the Pathogenetic Interaction Between Depression and Parkinson 's Disease. Brain Res Bull 2024:111001. [PMID: 38852651 DOI: 10.1016/j.brainresbull.2024.111001] [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: 11/28/2023] [Revised: 05/27/2024] [Accepted: 06/06/2024] [Indexed: 06/11/2024]
Abstract
Depression and Parkinson's disease share pathogenetic characteristics, meaning that they can impact each other and exacerbate their respective progression. From a pathogenetic perspective, depression can develop into Parkinson's disease and is a precursor symptom of Parkinson's disease; Parkinson's disease is also often accompanied by depression. From a pharmacological perspective, the use of antidepressants increases the risk of developing Parkinson's disease, and therapeutic medications for Parkinson's disease can exacerbate symptoms of depression. Therefore, identifying how Parkinson's disease and depression impact each other in their development is key to formulating preventive measures and targeted treatment. One commonality in the pathogenesis of depression and Parkinson's disease are alterations in the gut microbiota, with mechanisms interacting in neural, immune inflammatory, and neuroendocrine pathways. This paper reviews the role of gut microbiota in the pathogenesis of depression and Parkinson's disease; conducts a study of the relationship between both conditions and medication; and suggests that dysregulated gut microbiota may be a key factor in explaining the relationship between Parkinson's disease and depression. Finally, on the basis of these findings, this article hopes to provide suggestions that new ideas for the prevention and treatment of depression and Parkinson's disease.
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Affiliation(s)
- Peiyun Zhang
- The Second Affiliated Hospital of Zhejiang Chinese Medical University, HangZhou310005, China
| | - J Wei
- The First Clinical Medical College of Zhejiang Chinese Medical University, HangZhou310053, China
| | - L Zhaoshun
- The Second Affiliated Hospital of Zhejiang Chinese Medical University, HangZhou310005, China
| | - L Xingxuan
- The Second Affiliated Hospital of Zhejiang Chinese Medical University, HangZhou310005, China
| | - Lihong Li
- The Second Affiliated Hospital of Zhejiang Chinese Medical University, HangZhou310005, China.
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2
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Design and Synthesis of New Quinazolin-4-one Derivatives with Negative mGlu 7 Receptor Modulation Activity and Antipsychotic-Like Properties. Int J Mol Sci 2023; 24:ijms24031981. [PMID: 36768302 PMCID: PMC9916658 DOI: 10.3390/ijms24031981] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 12/19/2022] [Accepted: 12/20/2022] [Indexed: 01/21/2023] Open
Abstract
Following the glutamatergic theory of schizophrenia and based on our previous study regarding the antipsychotic-like activity of mGlu7 NAMs, we synthesized a new compound library containing 103 members, which were examined for NAM mGlu7 activity in the T-REx 293 cell line expressing a recombinant human mGlu7 receptor. Out of the twenty-two scaffolds examined, active compounds were found only within the quinazolinone chemotype. 2-(2-Chlorophenyl)-6-(2,3-dimethoxyphenyl)-3-methylquinazolin-4(3H)-one (A9-7, ALX-171, mGlu7 IC50 = 6.14 µM) was selective over other group III mGlu receptors (mGlu4 and mGlu8), exhibited satisfactory drug-like properties in preliminary DMPK profiling, and was further tested in animal models of antipsychotic-like activity, assessing the positive, negative, and cognitive symptoms. ALX-171 reversed DOI-induced head twitches and MK-801-induced disruptions of social interactions or cognition in the novel object recognition test and spatial delayed alternation test. On the other hand, the efficacy of the compound was not observed in the MK-801-induced hyperactivity test or prepulse inhibition. In summary, the observed antipsychotic activity profile of ALX-171 justifies the further development of the group of quinazolin-4-one derivatives in the search for a new drug candidate for schizophrenia treatment.
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3
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Hoglund BK, Carfagno V, Olive MF, Leyrer-Jackson JM. Metabotropic glutamate receptors and cognition: From underlying plasticity and neuroprotection to cognitive disorders and therapeutic targets. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2023; 168:367-413. [PMID: 36868635 DOI: 10.1016/bs.irn.2022.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Metabotropic glutamate (mGlu) receptors are G protein-coupled receptors that play pivotal roles in mediating the activity of neurons and other cell types within the brain, communication between cell types, synaptic plasticity, and gene expression. As such, these receptors play an important role in a number of cognitive processes. In this chapter, we discuss the role of mGlu receptors in various forms of cognition and their underlying physiology, with an emphasis on cognitive dysfunction. Specifically, we highlight evidence that links mGlu physiology to cognitive dysfunction across brain disorders including Parkinson's disease, Alzheimer's disease, Fragile X syndrome, post-traumatic stress disorder, and schizophrenia. We also provide recent evidence demonstrating that mGlu receptors may elicit neuroprotective effects in particular disease states. Lastly, we discuss how mGlu receptors can be targeted utilizing positive and negative allosteric modulators as well as subtype specific agonists and antagonist to restore cognitive function across these disorders.
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Affiliation(s)
- Brandon K Hoglund
- Department of Medical Education, School of Medicine, Creighton University, Phoenix, AZ, United States
| | - Vincent Carfagno
- School of Medicine, Midwestern University, Glendale, AZ, United States
| | - M Foster Olive
- Department of Psychology, Arizona State University, Tempe, AZ, United States
| | - Jonna M Leyrer-Jackson
- Department of Medical Education, School of Medicine, Creighton University, Phoenix, AZ, United States.
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4
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Bashir Y, Khan AU. The interplay between the gut-brain axis and the microbiome: A perspective on psychiatric and neurodegenerative disorders. Front Neurosci 2022; 16:1030694. [PMID: 36389228 PMCID: PMC9650127 DOI: 10.3389/fnins.2022.1030694] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/12/2022] [Indexed: 07/26/2023] Open
Abstract
What is the effect of our gut microbial flora on brain? Does the gut microbiome have any role in the causation of psychiatric and neurodegenerative diseases? Does the effect of gut microbiota traverse the gut-brain axis? Questions like these have captured the interest and imagination of the scientific community for quite some time now. Research in the quest for answers to these questions, to unravel the potential role of the microbiota inhabiting the gut in controlling brain functions, has progressed manifold over the last two decades. Although the possibility of microbiome as a key susceptibility factor for neurological disorders viz. Parkinson's disease, Alzheimer's disease, multiple sclerosis, and autism spectrum disorder has bolstered by an increase in the clinical and preclinical evidence, the field is still in its infancy. Given the fact that the diversity of the gut microbiota is affected by various factors including the diet and exercise, the interpretation of such data becomes all the more difficult. Also, such studies have been mostly conducted on animal models, so there is a need for randomized controlled trials in human subjects, corroborated by longitudinal studies, to establish if modulating the gut microbiota can unravel novel therapeutic interventions. Exploring the genomic, metagenomic and metabolomic data from clinical subjects with psychiatric and neurological diseases can prove to be a helpful guide in individual treatment selection.
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Blocking Metabotropic Glutamate Receptor Subtype 7 via the Venus Flytrap Domain Promotes a Chronic Stress-Resilient Phenotype in Mice. Cells 2022; 11:cells11111817. [PMID: 35681512 PMCID: PMC9180111 DOI: 10.3390/cells11111817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/30/2022] [Accepted: 05/31/2022] [Indexed: 12/01/2022] Open
Abstract
Chronic psychosocial stress participates prominently in the etiology of various psychiatric conditions and comorbid somatic pathologies; however, suitable pharmacotherapy of these disorders is still of high medical need. During the last few decades, research on mGlu receptors advanced remarkably and much attention was given to the mGlu7 subtype. Here, genetic mGlu7 ablation, short-term pharmacological mGlu7 blockade, as well as siRNA-mediated knockdown of mGlu7 were shown to result in an acute anti-stress, antidepressant- and anxiolytic-like phenotype in mice. Moreover, we recently revealed a prominent stress-protective effect of genetic mGlu7 ablation also with respect to chronic psychosocial stress. In addition, we are able to demonstrate in the present study that the chronic pharmacological blockade of mGlu7 interferes with various chronic stress-induced alterations. For this, we used the chronic subordinate colony housing (CSC), a mouse model of chronic male subordination, in combination with chronic treatment with the mGlu7-selective orthosteric-like antagonist XAP044 (7-hydroxy-3-(4-iodophenoxy)-4H-chromen-4-one). Interestingly, XAP044 dose-dependently ameliorates hypothalamic–pituitary–adrenal axis dysfunctions, thymus atrophy, as well as the CSC-induced increase in innate anxiety. Taken together, our findings provide further evidence for the role of mGlu7 in chronic psychosocial stress-induced alterations and suggests the pharmacological blockade of mGlu7 as a promising therapeutic approach for the treatment of chronic stress-related pathologies in men.
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Neurogenetics of dynamic connectivity patterns associated with obsessive-compulsive symptoms in healthy children. BIOLOGICAL PSYCHIATRY GLOBAL OPEN SCIENCE 2021; 2:411-420. [DOI: 10.1016/j.bpsgos.2021.11.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/28/2021] [Accepted: 11/14/2021] [Indexed: 01/31/2023] Open
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The role of microbiota-gut-brain axis in neuropsychiatric and neurological disorders. Pharmacol Res 2021; 172:105840. [PMID: 34450312 DOI: 10.1016/j.phrs.2021.105840] [Citation(s) in RCA: 195] [Impact Index Per Article: 65.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 08/14/2021] [Accepted: 08/17/2021] [Indexed: 12/12/2022]
Abstract
Emerging evidence indicates that the gut microbiota play a crucial role in the bidirectional communication between the gut and the brain suggesting that the gut microbes may shape neural development, modulate neurotransmission and affect behavior, and thereby contribute to the pathogenesis and/or progression of many neurodevelopmental, neuropsychiatric, and neurological conditions. This review summarizes recent data on the role of microbiota-gut-brain axis in the pathophysiology of neuropsychiatric and neurological disorders including depression, anxiety, schizophrenia, autism spectrum disorders, Parkinson's disease, migraine, and epilepsy. Also, the involvement of microbiota in gut disorders co-existing with neuropsychiatric conditions is highlighted. We discuss data from both in vivo preclinical experiments and clinical reports including: (1) studies in germ-free animals, (2) studies exploring the gut microbiota composition in animal models of diseases or in humans, (3) studies evaluating the effects of probiotic, prebiotic or antibiotic treatment as well as (4) the effects of fecal microbiota transplantation.
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Gibbons AS, Hoyer D, Dean B. SMAD4 protein is decreased in the dorsolateral prefrontal and anterior cingulate cortices in schizophrenia. World J Biol Psychiatry 2021; 22:70-77. [PMID: 32081064 DOI: 10.1080/15622975.2020.1733081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
OBJECTIVES Signal transduction through the mothers against decapentaplegic (SMAD) is a family of signal transduction factors that mediate signalling of the transforming growth factor B (TGFB)-superfamily of cell regulatory proteins. A recent transcriptomic analysis of post-mortem, cortical tissue from subjects with schizophrenia found decreased mRNA expression of SMAD2 and SMAD4 in the dorsolateral prefrontal cortex (DLPFC) associated with the disorder. To expand this initial finding, we sought to determine whether SMAD2 and SMAD4 protein were also altered in the cortex from subjects with schizophrenia. METHODS Western blotting was used to measure SMAD2 and SMAD4 protein levels in DLPFC and anterior cingulate cortex (ACC) taken post-mortem from subjects with schizophrenia (n = 20) and matched control (n = 20) subjects. RESULTS Compared to controls, levels of SMAD4 were 25% lower in the DLPFC and 38% lower in the ACC from subjects with schizophrenia. By contrast, SMAD2 levels were not altered in either DLPFC or ACC. CONCLUSIONS Our finding of lower SMAD4 protein in the cortex suggests there are likely to be abnormalities in cortical TGFB-superfamily signalling in schizophrenia.
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Affiliation(s)
- Andrew S Gibbons
- The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia.,The Department of Psychiatry, Monash University, Clayton, Victoria, Australia
| | - Daniel Hoyer
- The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia.,Department of Pharmacology and Therapeutics, School of Biomedical Sciences, University of Melbourne, Parkville, Victoria, Australia.,Department of Molecular Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Brian Dean
- The Florey Institute for Neuroscience and Mental Health, Parkville, Victoria, Australia.,Brain and Psychological Sciences Research Centre, Swinburne University of Technology, Hawthorn, Victoria, Australia
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Boccella S, Marabese I, Guida F, Luongo L, Maione S, Palazzo E. The Modulation of Pain by Metabotropic Glutamate Receptors 7 and 8 in the Dorsal Striatum. Curr Neuropharmacol 2020; 18:34-50. [PMID: 31210112 PMCID: PMC7327935 DOI: 10.2174/1570159x17666190618121859] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/01/2019] [Accepted: 05/31/2019] [Indexed: 12/28/2022] Open
Abstract
The dorsal striatum, apart from controlling voluntary movement, displays a recently demonstrated pain inhibition. It is connected to the descending pain modulatory system and in particular to the rostral ventromedial medulla through the medullary dorsal reticular nucleus. Diseases of the basal ganglia, such as Parkinson's disease, in addition to being characterized by motor disorders, are associated with pain and hyperactivation of the excitatory transmission. A way to counteract glutamatergic hyperactivation is through the activation of group III metabotropic glutamate receptors (mGluRs), which are located on presynaptic terminals inhibiting neurotransmitter release. So far the mGluRs of group III have been the least investigated, owing to a lack of selective tools. More recently, selective ligands for each mGluR of group III, in particular positive and negative allosteric modulators, have been developed and the role of each subtype is starting to emerge. The neuroprotective potential of group III mGluRs in pathological conditions, such as those characterized by elevate glutamate, has been recently shown. In the dorsal striatum, mGluR7 and mGluR8 are located at glutamatergic corticostriatal terminals and their stimulation inhibits pain in pathological conditions such as neuropathic pain. The two receptors in the dorsal striatum have instead a different role in pain control in normal conditions. This review will discuss recent results focusing on the contribution of mGluR7 and mGluR8 in the dorsal striatal control of pain. The role of mGluR4, whose antiparkinsonian activity is widely reported, will also be addressed.
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Affiliation(s)
- Serena Boccella
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - Ida Marabese
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - Francesca Guida
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - Livio Luongo
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - Sabatino Maione
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - Enza Palazzo
- Department of Experimental Medicine, Pharmacology Division, University of Campania "L. Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
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10
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Impact of the metabotropic glutamate receptor7 (mGlu 7) allosteric agonist, AMN082, on fear learning and memory and anxiety-like behavior. Eur J Pharmacol 2019; 858:172512. [PMID: 31260653 DOI: 10.1016/j.ejphar.2019.172512] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/19/2019] [Accepted: 06/27/2019] [Indexed: 12/30/2022]
Abstract
The present study was conducted to evaluate the influence of AMN082, the metabotropic glutamate receptor subtype 7 (mGlu7) allosteric agonist on different stages of memory processes connected with fear conditioning in the passive avoidance (PA) learning task in mice and negative emotional state (anxiety-like) induced by ethanol- and morphine-withdrawal in the elevated plus maze (EPM) test in rats. To perform the PA test, AMN082 (1.25, 2.5 and 5 mg/kg, i. p.) was injected to interfere with (or inhibit) acquisition, consolidation, and retrieval processes. The retention latency in each group was recorded using a step-through passive avoidance task 24 h after training. In turn, in ethanol- and morphine-withdrawal rats, the influence of AMN082 on anxiety-like behavior was estimated in the EPM test 24 h- (ethanol) and 72- h (morphine) after the last dose of repeated drug administrations. In all experimental groups, AMN082 at the dose of 5 mg/kg significantly decreased the step-through latency of long-term memory in the PA task. These AMN082 effects were reversed by MMPIP (10 mg/kg), the antagonist of mGlu7 receptor. AMN082 (2.5 and 5 mg/kg) also decreased ethanol- and morphine withdrawal-induced anxiety-like behavior in the EPM test, and this AMN082 (5 mg/kg) effect was counteracted by MMPIP pretreatment. Taken together, the results show that mGlu7 is involved in fear learning to the context and anxiety-like state connected with unpleasant experiences after ethanol- and morphine withdrawal in rodents. However, it appears that functional dissociation exists between these two AMN082 effects.
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11
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Gowrishankar R, Bruchas MR. Defining circuit-specific roles for G protein-coupled receptors in aversive learning. Curr Opin Behav Sci 2019; 26:146-156. [PMID: 32855999 DOI: 10.1016/j.cobeha.2019.01.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The encoding of negative valence in response to noxious stimuli/experiences and in turn, the behavioral representation of negative affective states is essential for survival. Recent advances in neuroscience have determined multiple sites of neural plasticity and key circuits of connectivity across these regions in mediating aversive behavior. G protein-coupled receptors (GPCRs), owing to their neuromodulatory role, are especially important to refining our understanding of the molecular substrates involved in these circuits. In this review, we will focus on recent, contemporary findings that explore neural circuit-specific roles for neurotransmitter/peptide GPCRs and the importance of using novel approaches to illuminate the molecular mechanisms central to aversive learning.
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Affiliation(s)
- Raajaram Gowrishankar
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195
| | - Michael R Bruchas
- Department of Anesthesiology and Pain Medicine, University of Washington, Seattle, WA 98195.,Department of Pharmacology, Center for the Neurobiology of Addiction, University of Washington, Seattle, WA 98195.,Pain and Emotion, University of Washington, Seattle, WA 98195
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12
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Cid JM, Lavreysen H, Tresadern G, Pérez-Benito L, Tovar F, Fontana A, Trabanco AA. Computationally Guided Identification of Allosteric Agonists of the Metabotropic Glutamate 7 Receptor. ACS Chem Neurosci 2019; 10:1043-1054. [PMID: 30216043 DOI: 10.1021/acschemneuro.8b00331] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The metabotropic glutamate 7 (mGlu7) receptor belongs to the group III of mGlu receptors. Since the mGlu7 receptor can control excitatory neurotransmission in the hippocampus and cortex, modulation of the receptor may have therapeutic benefit in several CNS diseases. However, mGlu7 remains relatively unexplored among the eight known mGlu receptors partly because of the limited availability of tool compounds to interrogate its potential therapeutic utility. Here we report the discovery of a new class of mGlu7 allosteric agonists. Hits originating from virtual screening were followed up with further analogue searching and screening, leading to a novel series of mGlu7 allosteric agonists. Guided by docking into a structural model of the mGlu7 receptor the initial hit 5 was successfully optimized to analogues with comparable potencies and more attractive drug-like attributes than AMN082.
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Affiliation(s)
- Jose María Cid
- Janssen Research and Development, Calle Jarama 75A, Toledo 45007, Spain
| | - Hilde Lavreysen
- Janssen Research and Development, Turnhoutseweg 30, 2440 Beerse, Belgium
| | - Gary Tresadern
- Janssen Research and Development, Turnhoutseweg 30, 2440 Beerse, Belgium
| | - Laura Pérez-Benito
- Laboratori de Medicina Computacional Unitat de Bioestadistica, Facultat de Medicina, Universitat Autonoma de Barcelona, Bellaterra 08193, Spain
| | - Fulgencio Tovar
- Villapharma Research
S.L., Parque Tecnológico de Fuente Álamo. Ctra. El Estrecho-Lobosillo, Km. 2.5- Av. Azul, 30320 Fuente Álamo de Murcia, Murcia, Spain
| | - Alberto Fontana
- Janssen Research and Development, Calle Jarama 75A, Toledo 45007, Spain
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O’Connor RM, McCafferty CP, Bravo JA, Singewald N, Holmes A, Cryan JF. Increased amygdalar metabotropic glutamate receptor 7 mRNA in a genetic mouse model of impaired fear extinction. Psychopharmacology (Berl) 2019; 236:265-272. [PMID: 30215216 PMCID: PMC6739849 DOI: 10.1007/s00213-018-5031-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Accepted: 09/05/2018] [Indexed: 12/18/2022]
Abstract
RATIONALE Post-traumatic stress disorder (PTSD) is a devastating anxiety-related disorder which develops subsequent to a severe psychologically traumatic event. Only ~ 9% of people who experience such a trauma develop PTSD. It is clear that a number of factors, including genetics, influence whether an individual will develop PTSD subsequent to a trauma. The 129S1/SvImJ (S1) inbred mouse strain displays poor fear extinction and may be useful to model this specific aspect of PTSD. The metabotropic glutamate receptor 7 (mGlu7 receptor) has previously been shown to be involved in cognitive processes and anxiety-like behaviour placing it in a key position to regulate fear extinction processes. We sought to compare mGlu7 receptor mRNA levels in the S1 strain with those in the robustly extinguishing C57BL/6J (B6) inbred strain using in situ hybridisation (ISH) in three brain regions associated with fear extinction: the amygdala, hippocampus and prefrontal cortex (PFC). RESULTS Compared to the B6 strain, S1 mice had increased mGlu7 receptor mRNA levels in the lateral amygdala (LA) and basolateral amygdala (BLA) subdivisions. An increase was also seen in the hippocampal CA1 and CA3 subregions of S1 mice. No difference in mGlu7 receptor levels were seen in the central nucleus (CeA) of the amygdala, dentate gyrus (DG) of the hippocampus or prefrontal cortex. CONCLUSIONS These data show altered mGlu7 receptor expression in key brain regions associated with fear extinction in two different inbred mouse strains which differ markedly in their fear extinction behaviour. Altered mGlu7 receptor levels may contribute to the deficit fear extinction processes seen in fear extinction in the S1 strain.
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Affiliation(s)
- Richard M. O’Connor
- Department of Anatomy and Neuroscience and APC Microbiome Institute, University College Cork, Cork, Ireland,Department of Neuroscience, Icahn School of Medicine at Mount Sinai, S10-20 Hess CSM, 1470 Madison Avenue, New York, NY 10029, USA,Present address: Department of Neuroscience, Icahn School of Medicine, Mount Sinai Hospital, New York, NY, USA
| | - Cian P. McCafferty
- Department of Anatomy and Neuroscience and APC Microbiome Institute, University College Cork, Cork, Ireland,Present address: Department of Neurology, Yale University School of Medicine, New Haven, CT, USA
| | - Javier A. Bravo
- Grupo de NeuroGastroBioquímica, Laboratorio e Química Biológica & Bioquímica de Sistemas, Instituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | - Nicolas Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck, Austria
| | - Andrew Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Rockville, MD, USA
| | - John F. Cryan
- Department of Anatomy and Neuroscience and APC Microbiome Institute, University College Cork, Cork, Ireland
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14
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Fisher NM, Seto M, Lindsley CW, Niswender CM. Metabotropic Glutamate Receptor 7: A New Therapeutic Target in Neurodevelopmental Disorders. Front Mol Neurosci 2018; 11:387. [PMID: 30405350 PMCID: PMC6206046 DOI: 10.3389/fnmol.2018.00387] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 10/01/2018] [Indexed: 12/27/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) are characterized by a wide range of symptoms including delayed speech, intellectual disability, motor dysfunction, social deficits, breathing problems, structural abnormalities, and epilepsy. Unfortunately, current treatment strategies are limited and innovative new approaches are sorely needed to address these complex diseases. The metabotropic glutamate receptors are a class of G protein-coupled receptors that act to modulate neurotransmission across many brain structures. They have shown great promise as drug targets for numerous neurological and psychiatric diseases. Moreover, the development of subtype-selective allosteric modulators has allowed detailed studies of each receptor subtype. Here, we focus on the metabotropic glutamate receptor 7 (mGlu7) as a potential therapeutic target for NDDs. mGlu7 is expressed widely throughout the brain in regions that correspond to the symptom domains listed above and has established roles in synaptic physiology and behavior. Single nucleotide polymorphisms and mutations in the GRM7 gene have been associated with idiopathic autism and other NDDs in patients. In rodent models, existing literature suggests that decreased mGlu7 expression and/or function may lead to symptoms that overlap with those of NDDs. Furthermore, potentiation of mGlu7 activity has shown efficacy in a mouse model of Rett syndrome. In this review, we summarize current findings that provide rationale for the continued development of mGlu7 modulators as potential therapeutics.
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Affiliation(s)
- Nicole M Fisher
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, United States
| | - Mabel Seto
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, United States
| | - Craig W Lindsley
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, United States.,Department of Chemistry, Vanderbilt University, Nashville, TN, United States
| | - Colleen M Niswender
- Department of Pharmacology and Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN, United States.,Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN, United States
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15
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Fisher NM, Gogliotti RG, Vermudez SAD, Stansley BJ, Conn PJ, Niswender CM. Genetic Reduction or Negative Modulation of mGlu 7 Does Not Impact Anxiety and Fear Learning Phenotypes in a Mouse Model of MECP2 Duplication Syndrome. ACS Chem Neurosci 2018; 9:2210-2217. [PMID: 29227625 DOI: 10.1021/acschemneuro.7b00414] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Rett syndrome and MECP2 Duplication syndrome are neurodevelopmental disorders attributed to loss-of-function mutations in, or duplication of, the gene encoding methyl-CpG-binding protein 2 (MeCP2), respectively. We recently reported decreased expression and function of the metabotropic glutamate receptor 7 (mGlu7) in a mouse model of Rett syndrome. Positive allosteric modulation of mGlu7 activity was sufficient to improve several disease phenotypes including cognition. Here, we tested the hypothesis that mGlu7 expression would be reciprocally regulated in a mouse model of MECP2 Duplication syndrome, such that negative modulation of mGlu7 activity would exert therapeutic benefit. To the contrary, we report that mGlu7 is not functionally increased in mice overexpressing MeCP2 and that neither genetic nor pharmacological reduction of mGlu7 activity impacts phenotypes that are antiparallel to those observed in Rett syndrome model mice. These data expand our understanding of how mGlu7 expression and function is affected by changes in MeCP2 dosage and have important implications for the therapeutic development of mGlu7 modulators.
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Affiliation(s)
- Nicole M. Fisher
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Rocco G. Gogliotti
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Sheryl Anne D. Vermudez
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Branden J. Stansley
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - P. Jeffrey Conn
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Colleen M. Niswender
- Department of Pharmacology, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, Tennessee 37232, United States
- Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
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16
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Artigas F, Celada P, Bortolozzi A. Can we increase the speed and efficacy of antidepressant treatments? Part II. Glutamatergic and RNA interference strategies. Eur Neuropsychopharmacol 2018. [PMID: 29525411 DOI: 10.1016/j.euroneuro.2018.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
In the second part we focus on two treatment strategies that may overcome the main limitations of current antidepressant drugs. First, we review the experimental and clinical evidence supporting the use of glutamatergic drugs as fast-acting antidepressants. Secondly, we review the involvement of microRNAs (miRNAs) in the pathophysiology of major depressive disorder (MDD) and the use of small RNAs (e.g.., small interfering RNAs or siRNAs) to knockdown genes in monoaminergic and non-monoaminergic neurons and induce antidepressant-like responses in experimental animals. The development of glutamatergic agents is a promising venue for antidepressant drug development, given the antidepressant properties of the non-competitive NMDA receptor antagonist ketamine. Its unique properties appear to result from the activation of AMPA receptors by a metabolite [(2S,6S;2R,6R)-hydroxynorketamine (HNK)] and mTOR signaling. These effects increase synaptogenesis in prefrontal cortical pyramidal neurons and enhance serotonergic neurotransmission via descending inputs to the raphe nuclei. This view is supported by the cancellation of ketamine's antidepressant-like effects by inhibition of serotonin synthesis. We also review existing evidence supporting the involvement of miRNAs in MDD and the preclinical use of RNA interference (RNAi) strategies to target genes involved in antidepressant response. Many miRNAs have been associated to MDD, some of which e.g., miR-135 targets genes involved in antidepressant actions. Likewise, SSRI-conjugated siRNA evokes faster and/or more effective antidepressant-like responses. Intranasal application of sertraline-conjugated siRNAs directed to 5-HT1A receptors and SERT evoked much faster changes of pre- and postsynaptic antidepressant markers than those produced by fluoxetine.
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Affiliation(s)
- F Artigas
- Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Spain; CIBERSAM (Centro de Investigació Biomédica en Red de Salud Mental), Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Spain.
| | - P Celada
- Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Spain; CIBERSAM (Centro de Investigació Biomédica en Red de Salud Mental), Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Spain
| | - A Bortolozzi
- Department of Neurochemistry and Neuropharmacology, Institut d'Investigacions Biomèdiques de Barcelona, Consejo Superior de Investigaciones Científicas (CSIC), Spain; CIBERSAM (Centro de Investigació Biomédica en Red de Salud Mental), Spain; Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Spain
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17
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Hajasova Z, Canestrelli C, Acher F, Noble F, Marie N. Role of mGlu7 receptor in morphine rewarding effects is uncovered by a novel orthosteric agonist. Neuropharmacology 2018; 131:424-430. [PMID: 29307544 DOI: 10.1016/j.neuropharm.2018.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 12/26/2017] [Accepted: 01/02/2018] [Indexed: 11/26/2022]
Abstract
Opiate dependence is a major health issue and despite the existence of opioid substitution treatment, relapse frequently occurs. Group III metabotropic glutamate (mGlu) receptors has received much attention as a putative target in ethanol and cocaine addiction, but no data on opiate addiction exist. So we investigated the role of group III mGlu receptors in morphine rewarding effects through the expression and the reinstatement of conditioned place preference (CPP) using a newly synthesized mGlu4/mGlu7 receptor orthosteric agonist, LSP2-9166. We found that LSP2-9166 blocked morphine CPP expression and reinstatement after extinction. Blockade of CPP expression with LSP2-9166 was abolished when using XAP044, a mGlu7 antagonist. We also found that LSP2-9166 at the dose active for blocking morphine reward was devoid of any effect on locomotion, hedonic state, spatial memory, anxiety or depression. Altogether our data demonstrated that group III mGlu receptors, and more specifically mGlu7, might be a valuable target in opiate addiction.
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Affiliation(s)
- Zuzana Hajasova
- CNRS ERL 3649, Neuroplasticité et Thérapie des Addictions, Paris, France; INSERM UMR-S 1124, Paris, France; Université Paris Descartes, Paris, France
| | - Corinne Canestrelli
- CNRS ERL 3649, Neuroplasticité et Thérapie des Addictions, Paris, France; INSERM UMR-S 1124, Paris, France; Université Paris Descartes, Paris, France
| | - Francine Acher
- Université Paris Descartes, Paris, France; CNRS UMR8601, Laboratoire de Chimie & Biochimie Pharmacologiques et Toxicologiques, Paris, France
| | - Florence Noble
- CNRS ERL 3649, Neuroplasticité et Thérapie des Addictions, Paris, France; INSERM UMR-S 1124, Paris, France; Université Paris Descartes, Paris, France
| | - Nicolas Marie
- CNRS ERL 3649, Neuroplasticité et Thérapie des Addictions, Paris, France; INSERM UMR-S 1124, Paris, France; Université Paris Descartes, Paris, France.
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18
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Pharmacological modulation of metabotropic glutamate receptor subtype 5 and 7 impairs extinction of social fear in a time-point-dependent manner. Behav Brain Res 2017; 328:57-61. [DOI: 10.1016/j.bbr.2017.04.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 04/03/2017] [Accepted: 04/05/2017] [Indexed: 11/17/2022]
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Kahl E, Fendt M. Metabotropic Glutamate Receptors 7 within the Nucleus Accumbens are Involved in Relief Learning in Rats. Curr Neuropharmacol 2017; 14:405-12. [PMID: 27296637 PMCID: PMC4983753 DOI: 10.2174/1570159x13666150425002017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Revised: 03/03/2015] [Accepted: 04/22/2016] [Indexed: 11/26/2022] Open
Abstract
Relief learning is an appetitive association of a formally neutral cue with relief induced by the offset of an aversive stimulus. Since the nucleus accumbens mediates relief learning and accumbal metabotropic glutamate receptors 7 (mGluR7) modulate appetitive-like processes, we hypothesized that accumbal mGluR7 may be involved in the modulation of relief learning. Therefore, we injected the allosteric mGluR7 agonist AMN082 into the nucleus accumbens and tested the effects of these injections on acquisition and expression of relief memory, as well as on the reactivity to electric stimuli. AMN082 injections blocked acquisition but not expression of relief memory. In addition, accumbal AMN082 injections strongly reduced the locomotor reactivity to electric stimuli indicating antinociceptive effects. These antinociceptive effects might be causal for the blockade of relief learning after AMN082 injections. Taken together, the present study indicates that functional activation of accumbal mGluR7 has antinociceptive effects that interfere with relief learning.
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Affiliation(s)
| | - Markus Fendt
- Institute for Pharmacology and Toxicology, Leipziger Straße 44, D-39120 Magdeburg, Germany.
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20
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Palazzo E, Marabese I, de Novellis V, Rossi F, Maione S. Metabotropic Glutamate Receptor 7: From Synaptic Function to Therapeutic Implications. Curr Neuropharmacol 2017; 14:504-13. [PMID: 27306064 PMCID: PMC4983754 DOI: 10.2174/1570159x13666150716165323] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Revised: 05/20/2015] [Accepted: 07/14/2015] [Indexed: 11/22/2022] Open
Abstract
Metabotropic glutamate receptor 7 (mGluR7) is localized presynaptically at the active zone of neurotransmitter release. Unlike mGluR4 and mGluR8, which share mGluR7's presynaptic location, mGluR7 shows low affinity for glutamate and is activated only by high glutamate concentrations. Its wide distribution in the central nervous system (CNS) and evolutionary conservation across species suggest that mGluR7 plays a primary role in controlling excitatory synapse function. High mGluR7 expression has been observed in several brain regions that are critical for CNS functioning and are involved in neurological and psychiatric disorder development. Until the recent discovery of selective ligands for mGluR7, techniques to elucidate its role in neural function were limited to the use of knockout mice and gene silencing. Studies using these two techniques have revealed that mGluR7 modulates emotionality, stress and fear responses. N,N`-dibenzhydrylethane-1,2-diamine dihydrochloride (AMN082) was reported as the first selective mGluR7 allosteric agonist. Pharmacological effects of AMN082 have not completely confirmed the mGluR7-knockout mouse phenotype; this has been attributed to rapid receptor internalization after drug treatment and to the drug's apparent lack of in vivo selectivity. Therefore, the more recently developed mGluR7 negative allosteric modulators (NAMs) are crucial for understanding mGluR7 function and for exploiting its potential as a target for therapeutic interventions. This review presents the main findings regarding mGluR7's effect on modulation of synaptic function and its role in normal CNS function and in models of neurologic and psychiatric disorders.
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Affiliation(s)
- Enza Palazzo
- Department of Anesthesiology, Surgery and Emergency, The Second University of Naples, Piazza Luigi Miraglia 2, 80138 Naples, Italy.
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21
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Shaban H, O’Connor R, Ovsepian SV, Dinan TG, Cryan JF, Schellekens H. Electrophysiological approaches to unravel the neurobiological basis of appetite and satiety: use of the multielectrode array as a screening strategy. Drug Discov Today 2017; 22:31-42. [DOI: 10.1016/j.drudis.2016.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 08/03/2016] [Accepted: 09/06/2016] [Indexed: 01/10/2023]
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Sukumaran P, Sun Y, Schaar A, Selvaraj S, Singh BB. TRPC Channels and Parkinson's Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 976:85-94. [PMID: 28508315 DOI: 10.1007/978-94-024-1088-4_8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Parkinson's disease (PD) is a common neurodegenerative disorder, which involves degeneration of dopaminergic neurons that are present in the substantia nigra pars compacta (SNpc) region. Many factors have been identified that could lead to Parkinson's disease; however, almost all of them are directly or indirectly dependent on Ca2+ signaling. Importantly, though disturbances in Ca2+ homeostasis have been implicated in Parkinson's disease and other neuronal diseases, the identity of the calcium channel remains elusive. Members of the transient receptor potential canonical (TRPC) channel family have been identified as a new class of Ca2+ channels, and it could be anticipated that these channels could play important roles in neurodegenerative diseases, especially in PD. Thus, in this chapter we have entirely focused on TRPC channels and elucidated its role in PD.
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Affiliation(s)
- Pramod Sukumaran
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Yuyang Sun
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Anne Schaar
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Senthil Selvaraj
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA
| | - Brij B Singh
- Department of Biomedical Sciences, School of Medicine and Health Sciences, University of North Dakota, Grand Forks, ND, 58201, USA.
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Peterlik D, Stangl C, Bludau A, Grabski D, Strasser R, Schmidt D, Flor PJ, Uschold-Schmidt N. Relief from detrimental consequences of chronic psychosocial stress in mice deficient for the metabotropic glutamate receptor subtype 7. Neuropharmacology 2016; 115:139-148. [PMID: 27188844 DOI: 10.1016/j.neuropharm.2016.04.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 04/25/2016] [Accepted: 04/26/2016] [Indexed: 10/21/2022]
Abstract
Chronic stress-related psychiatric conditions and comorbid somatic pathologies are an enormous public health concern in modern society. The etiology of these disorders is complex, with stressors holding a chronic and psychosocial component representing the most acknowledged risk factor. During the last decades, research on the metabotropic glutamate receptor (mGlu) system advanced dramatically and much attention was given to the role of the metabotropic glutamate receptor subtype 7 (mGlu7) in acute stress-related behavior and physiology. However, virtually nothing is known about the potential involvement of mGlu7 in chronic psychosocial stress-related conditions. Using the chronic subordinate colony housing (CSC, 19 days) in male mice, we addressed whether central mGlu7 is altered upon chronic psychosocial stressor exposure and whether genetic ablation of mGlu7 interferes with the multitude of chronic stress-induced alterations. CSC exposure resulted in a downregulation of mGlu7 mRNA transcript levels in the prefrontal cortex, a brain region relevant for stress-related behaviors and physiology. Interestingly, mGlu7 deficiency relieved multiple chronic stress-induced alterations including the CSC-induced anxiety-prone phenotype; mGlu7 ablation also ameliorated CSC-induced physiological and immunological consequences such as hypothalamo-pituitary-adrenal (HPA) axis dysfunctions and colonic inflammation, respectively. Together, our findings provide first evidence for the involvement of mGlu7 in a wide range of behavioral and physiological alterations in response to chronic psychosocial stressor exposure. Moreover, the stress-protective phenotype of genetic mGlu7 ablation suggests mGlu7 pharmacological blockade to be a relevant option for the treatment of chronic stress-related emotional and somatic dysfunctions. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Daniel Peterlik
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Christina Stangl
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Anna Bludau
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Dominik Grabski
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Robert Strasser
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, Regensburg, Germany
| | - Dominic Schmidt
- Institute of Immunology, University of Regensburg, Regensburg, Germany
| | - Peter J Flor
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, Regensburg, Germany.
| | - Nicole Uschold-Schmidt
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, Regensburg, Germany.
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MicroRNA’s impact on neurotransmitter and neuropeptide systems: small but mighty mediators of anxiety. Pflugers Arch 2016; 468:1061-9. [DOI: 10.1007/s00424-016-1814-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 03/16/2016] [Accepted: 03/18/2016] [Indexed: 11/26/2022]
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25
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Li X, Markou A. Metabotropic Glutamate Receptor 7 (mGluR7) as a Target for the Treatment of Psychostimulant Dependence. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2016; 14:738-44. [PMID: 26022263 DOI: 10.2174/1871527314666150529145332] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 05/18/2015] [Indexed: 11/22/2022]
Abstract
Although few medications have been approved by the U.S. Food and Drug Administration (FDA) to assist people to quit tobacco smoking, there are no FDA-approved medications to treat dependence on other psychostimulant drugs, such as cocaine. The motivation to maintain psychostimulant drug seeking and self-administration involves alterations in glutamatergic neurotransmission. Thus, medications that modulate glutamate transmission may be effective treatments for psychostimulant dependence. One presynaptic inhibitory glutamate receptor that critically regulates glutamate transmission is the metabotropic glutamate 7 receptor (mGluR7). This review summarizes nonhuman experimental animal data that indicate a critical role for mGluR7 in drug-taking and drug-seeking behaviors for the psychostimulants cocaine and nicotine. AMN082, the only commercially available allosteric receptor agonist, has been used to investigate the role of mGluR7 in psychostimulant dependence. Systemic administration or microinjection of AMN082 into brain sites within the mesocorticolimbic system decreased self-administration and reinstatement of both cocaine and nicotine seeking. In vivo microdialysis results indicated that a nucleus accumbens-ventral pallidum γ-aminobutyric acid-ergic mechanism may underlie AMN082-induced antagonism of the reinforcing effects of cocaine, whereas a glutamate mGlu2/3 receptor mechanism underlies the AMN082-induced blockade of cocaine seeking. These findings indicate an important role for mGluR7 in mesolimbic areas in modulating the reinforcing effects of psychostimulant drugs, such as nicotine and cocaine, and the conditioned behaviors associated with drugs of abuse. Thus, selective mGluR7 agonists or positive allosteric modulators may have the potential to treat psychostimulant dependence.
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Affiliation(s)
| | - Athina Markou
- Department of Psychiatry, M/C 0603, School of Medicine, University of California San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0603, USA.
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MMPIP, an mGluR7-selective negative allosteric modulator, alleviates pain and normalizes affective and cognitive behavior in neuropathic mice. Pain 2016; 156:1060-1073. [PMID: 25760470 DOI: 10.1097/j.pain.0000000000000150] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
This study investigated the effects of a single administration of 6-(4-methoxyphenyl)-5-methyl-3-pyridinyl-4-isoxazolo[4,5-c]pyridin-4(5H)-one (MMPIP), a negative allosteric modulator (NAM) of metabotropic glutamate receptor 7 (mGluR7), on pain and on affective and cognitive behavior in neuropathic mice. The activity of pyramidal neurons in the prelimbic cortex (PLC), which respond to stimulation of the basolateral amygdala (BLA) with either excitation or inhibition, was also investigated. The spared nerve injury (SNI) of the sciatic nerve induced, 14 days after surgery, thermal hyperalgesia and mechanical allodynia, reduced open-arm choice in the elevated plus-maze, increased time of immobility in the tail suspension, and increased digging and burying in the marble burying test. Cognitive performance was also significantly compromised in the SNI mice. Spared nerve injury induced phenotypic changes on pyramidal neurons of the PLC; excitatory responses increased, whereas inhibitory responses decreased after BLA stimulation. mGluR7 expression, mainly associated with vesicular glutamate transporter, increased in the hippocampus and decreased in the BLA, PLC, and dorsal raphe in SNI mice. MMPIP increased thermal and mechanical thresholds and open-arm choice. It reduced the immobility in the tail suspension test and the number of marbles buried and of digging events in the marble burying test. MMPIP also improved cognitive performance and restored the balance between excitatory and inhibitory responses of PLC neurons in SNI mice. 7-hydroxy-3-(4-iodophenoxy)-4H-chromen-4-one, XAP044, another selective mGluR7 NAM, reproduced the effects of MMPIP on thermal hyperalgesia, mechanical allodynia, tail suspension, and marble burying test. Altogether, these findings show that mGluR7 NAMs reduce pain responses and affective/cognitive impairments in neuropathic pain conditions.
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Metabotropic Glutamate Receptor Subtype 7 in the Bed Nucleus of the Stria Terminalis is Essential for Intermale Aggression. Neuropsychopharmacology 2016; 41:726-35. [PMID: 26149357 PMCID: PMC4707819 DOI: 10.1038/npp.2015.198] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Revised: 06/23/2015] [Accepted: 06/29/2015] [Indexed: 12/25/2022]
Abstract
Metabotropic glutamate receptor subtype 7 (mGluR7) is a member of group III mGluRs, which localize to the presynaptic active zones of the mammalian central nervous system. Although histological, genetic, and electrophysiological studies ensure the importance of mGluR7, its roles in behavior and physiology remain largely unknown. Using a resident-intruder paradigm, we found a severe reduction in intermale aggressive behavior in mGluR7 knockout (KO) mice. We also found alterations in other social behaviors in male mGluR7 KO mice, including sexual behavior toward male intruders. Because olfaction is critical for rodent social behavior, including aggression, we performed an olfaction test, finding that mGluR7 KO mice failed to show interest in the smell of male urine. To clarify the olfactory deficit, we then exposed mice to urine and analyzed c-Fos-immunoreactivity, discovering a remarkable reduction in neural activity in the bed nucleus of the stria terminalis (BNST) of mGluR7 KO mice. Finally, intra-BNST administration of the mGluR7-selective antagonist 6-(4-methoxyphenyl)-5-methyl-3-pyridin-4-ylisoxazolo[4,5-c]pyridin-4(5H)-one (MMPIP) also reproduced the phenotype of mGluR7 KO mice, including reduced aggression and altered social interaction. Thus mGluR7 may work as an 'enhancer of neural activity' in the BNST and is important for intermale aggression. Our findings demonstrate that mGluR7 is essential for social behavior and innate behavior. Our study on mGluR7 in the BNST will shed light on future therapies for emotional disorders in humans.
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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.
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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.
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29
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Krishnan B, Scott MT, Pollandt S, Schroeder B, Kurosky A, Shinnick-Gallagher P. Fear potentiated startle increases phospholipase D (PLD) expression/activity and PLD-linked metabotropic glutamate receptor mediated post-tetanic potentiation in rat amygdala. Neurobiol Learn Mem 2015; 128:65-79. [PMID: 26748024 DOI: 10.1016/j.nlm.2015.12.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 12/08/2015] [Accepted: 12/25/2015] [Indexed: 12/30/2022]
Abstract
Long-term memory (LTM) of fear stores activity dependent modifications that include changes in amygdala signaling. Previously, we identified an enhanced probability of release of glutamate mediated signaling to be important in rat fear potentiated startle (FPS), a well-established translational behavioral measure of fear. Here, we investigated short- and long-term synaptic plasticity in FPS involving metabotropic glutamate receptors (mGluRs) and associated downstream proteomic changes in the thalamic-lateral amygdala pathway (Th-LA). Aldolase A, an inhibitor of phospholipase D (PLD), expression was reduced, concurrent with significantly elevated PLD protein expression. Blocking the PLD-mGluR signaling significantly reduced PLD activity. While transmitter release probability increased in FPS, PLD-mGluR agonist and antagonist actions were occluded. In the unpaired group (UNP), blocking the PLD-mGluR increased while activating the receptor decreased transmitter release probability, consistent with decreased synaptic potentials during tetanic stimulation. FPS Post-tetanic potentiation (PTP) immediately following long-term potentiation (LTP) induction was significantly increased. Blocking PLD-mGluR signaling prevented PTP and reduced cumulative PTP probability but not LTP maintenance in both groups. These effects are similar to those mediated through mGluR7, which is co-immunoprecipitated with PLD in FPS. Lastly, blocking mGluR-PLD in the rat amygdala was sufficient to prevent behavioral expression of fear memory. Thus, our study in the Th-LA pathway provides the first evidence for PLD as an important target of mGluR signaling in amygdala fear-associated memory. Importantly, the PLD-mGluR provides a novel therapeutic target for treating maladaptive fear memories in posttraumatic stress and anxiety disorders.
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Affiliation(s)
- Balaji Krishnan
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, TX, United States; UTMB Mitchell Center for Neurodegenerative Diseases, Department of Neurology, University of Texas Medical Branch, Galveston, TX, United States.
| | - Michael T Scott
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Sebastian Pollandt
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Bradley Schroeder
- Department of Pharmacology & Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Alexander Kurosky
- UTMB NHLBI Proteomics Center, Department of Biochemistry & Molecular Biology, University of Texas Medical Branch, Galveston, TX, United States
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mGluR2/3 in the Lateral Amygdala is Required for Fear Extinction: Cortical Input Synapses onto the Lateral Amygdala as a Target Site of the mGluR2/3 Action. Neuropsychopharmacology 2015; 40:2916-28. [PMID: 26081171 PMCID: PMC4864627 DOI: 10.1038/npp.2015.145] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 05/07/2015] [Accepted: 05/20/2015] [Indexed: 01/13/2023]
Abstract
Various subtypes of metabotropic glutamate receptors (mGluRs) have been implicated in fear extinction, but mGluR2/3 subtype has not been tested. Here, we found that microinjection of an mGluR2/3 antagonist, LY341495, into the lateral amygdala (LA), but not into the adjacent central amygdala (CeA), impaired extinction retention without affecting within-session extinction. In contrast, we failed to detect any significant changes in motility and anxiety during a period when extinction training or retention was performed after LY341495 injection, suggesting that the effect of LY341495 is specific to conditioned responses. Subsequently, on the basis of a previous finding that a long-term potentiation of presynaptic efficacy at cortical input synapses onto the lateral amygdala (C-LA synapses) supports conditioned fear, we tested the hypothesis that activation of mGluR2/3 leads to fear extinction via a long-term weakening of presynaptic functions at C-LA synapses. Fear extinction produced a decrease in C-LA synaptic efficacy, whereas LY341495 infusion into the LA blocked this extinction-induced C-LA efficacy decrease without altering synaptic efficacy at other LA synapses. Furthermore, extinction enhanced paired pulse ratio (PPR) of EPSCs, which inversely correlates with presynaptic release probability, whereas LY341495 infusion into the LA attenuated the extinction-induced increase in PPR, suggesting the presence of mGluR2/3-dependent presynaptic changes after extinction. Consistently, extinction occluded a presynaptic form of depression at C-LA synapses, whereas the LY341495 infusion into the LA rescued this occlusion. Together, our findings suggest that mGluR2/3 is required for extinction retention and that the mGluR2/3 action is mediated by the long-term weakening of release probability at C-LA synapses.
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HDAC inhibitors as cognitive enhancers in fear, anxiety and trauma therapy: where do we stand? Biochem Soc Trans 2015; 42:569-81. [PMID: 24646280 PMCID: PMC3961057 DOI: 10.1042/bst20130233] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A novel strategy to treat anxiety and fear-related disorders such as phobias, panic and PTSD (post-traumatic stress disorder) is combining CBT (cognitive behavioural therapy), including extinction-based exposure therapy, with cognitive enhancers. By targeting and boosting mechanisms underlying learning, drug development in this field aims at designing CBT-augmenting compounds that help to overcome extinction learning deficits, promote long-term fear inhibition and thus support relapse prevention. Progress in revealing the role of epigenetic regulation of specific genes associated with extinction memory generation has opened new avenues in this direction. The present review examines recent evidence from pre-clinical studies showing that increasing histone acetylation, either via genetic or pharmacological inhibition of HDACs (histone deacetylases) by e.g. vorinostat/SAHA (suberoylanilide hydroxamic acid), entinostat/MS-275, sodium butyrate, TSA (trichostatin A) or VPA (valproic acid), or by targeting HATs (histone acetyltransferases), augments fear extinction and, importantly, generates a long-term extinction memory that can protect from return of fear phenomena. The molecular mechanisms and pathways involved including BDNF (brain-derived neurotrophic factor) and NMDA (N-methyl-D-aspartate) receptor signalling are just beginning to be revealed. First studies in healthy humans are in support of extinction-facilitating effects of HDAC inhibitors. Very recent evidence that HDAC inhibitors can rescue deficits in extinction-memory-impaired rodents indicates a potential clinical utility of this approach also for exposure therapy-resistant patients. Important future work includes investigation of the long-term safety aspects of HDAC inhibitor treatment, as well as design of isotype(s)-specific inhibitors. Taken together, HDAC inhibitors display promising potential as pharmacological adjuncts to augment the efficacy of exposure-based approaches in anxiety and trauma therapy.
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32
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Liu Y, Zhang Y, Zhao D, Dong R, Yang X, Tammimies K, Uddin M, Scherer SW, Gai Z. Rare de novo deletion of metabotropic glutamate receptor 7 (GRM7) gene in a patient with autism spectrum disorder. Am J Med Genet B Neuropsychiatr Genet 2015; 168B:258-64. [PMID: 25921429 DOI: 10.1002/ajmg.b.32306] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2015] [Accepted: 02/22/2015] [Indexed: 12/28/2022]
Abstract
GRM7, the gene encoding metabotropic glutamate receptor 7 (mGluR7), have been implicated in multiple neuropsychiatric disorders and shown to mediate excitatory synaptic neurotransmitter signaling and plasticity in the mammalian brain. Here we report a 303 kb de novo deletion at band 3p26.1, disrupting five coding exons of GRM7 in a proband with autism spectrum disorder, and hyperactivity. Our exon transcriptome-mutation contingency index method shows that three of the exons within the breakpoint boundaries are under purifying selection and highly expressed in prenatal brain regions. Based on our results and a thorough review of the literature, we propose that haploinsufficiency of the GRM7 product (mGluR7) contributes to autism spectrum disorders and hyperactivity phenotype as seen in the patient described here.
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Affiliation(s)
- Yi Liu
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Yanqing Zhang
- Pediatric Health Care Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Dongmei Zhao
- Pediatric Health Care Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Rui Dong
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Xiaomeng Yang
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
| | - Kristiina Tammimies
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada.,The Center of Neurodevelopmental Disorders at Karolinska Institutet (KIND), Pediatric Neuropsychiatry Unit, Department of Women's and Children's Health, Karolinska Institutet, Stockholm, Sweden
| | - Mohammed Uddin
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada
| | - Stephen W Scherer
- The Centre for Applied Genomics, The Hospital for Sick Children, Toronto, Canada.,McLaughlin Centre and Department of Molecular Genetics, University ofToronto, Toronto, Canada
| | - Zhongtao Gai
- Pediatric Research Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China.,Pediatric Health Care Institute, Qilu Children's Hospital of Shandong University, Ji'nan, China
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33
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Moloney RD, Golubeva AV, O'Connor RM, Kalinichev M, Dinan TG, Cryan JF. Negative allosteric modulation of the mGlu7 receptor reduces visceral hypersensitivity in a stress-sensitive rat strain. Neurobiol Stress 2015; 2:28-33. [PMID: 26844237 PMCID: PMC4721404 DOI: 10.1016/j.ynstr.2015.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2014] [Revised: 03/15/2015] [Accepted: 04/03/2015] [Indexed: 11/19/2022] Open
Abstract
Glutamate, the main excitatory neurotransmitter in the central nervous system, exerts its effect through ionotropic and metabotropic receptors. Of these, group III mGlu receptors (mGlu 4, 6, 7, 8) are among the least studied due to a lack of pharmacological tools. mGlu7 receptors, the most highly conserved isoform, are abundantly distributed in the brain, especially in regions, such as the amygdala, known to be crucial for the emotional processing of painful stimuli. Visceral hypersensitivity is a poorly understood phenomenon manifesting as an increased sensitivity to visceral stimuli. Glutamate has long been associated with somatic pain processing leading us to postulate that crossover may exist between these two modalities. Moreover, stress has been shown to exacerbate visceral pain. ADX71743 is a novel, centrally penetrant, negative allosteric modulator of mGlu7 receptors. Thus, we used this tool to explore the possible involvement of this receptor in the mediation of visceral pain in a stress-sensitive model of visceral hypersensitivity, namely the Wistar Kyoto (WKY) rat. ADX71743 reduced visceral hypersensitivity in the WKY rat as exhibited by increased visceral sensitivity threshold with concomitant reductions in total number of pain behaviours. Moreover, AD71743 increased total distance and distance travelled in the inner zone of the open field. These findings show, for what is to our knowledge, the first time, that mGlu7 receptor signalling plays a role in visceral pain processing. Thus, negative modulation of the mGlu7 receptor may be a plausible target for the amelioration of stress-induced visceral pain where there is a large unmet medical need.
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Affiliation(s)
- Rachel D. Moloney
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Ireland
- Department of Psychiatry, University College Cork, Ireland
| | - Anna V. Golubeva
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Ireland
| | | | | | - Timothy G. Dinan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Ireland
- Department of Psychiatry, University College Cork, Ireland
| | - John F. Cryan
- Laboratory of Neurogastroenterology, Alimentary Pharmabiotic Centre, Biosciences Institute, University College Cork, Ireland
- Department of Anatomy and Neuroscience, University College Cork, Ireland
- Corresponding author. Dept Anatomy & Neuroscience, Room 386, Western Gateway Building, University College Cork, Western Rd., Cork, Ireland.
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34
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Singewald N, Schmuckermair C, Whittle N, Holmes A, Ressler KJ. Pharmacology of cognitive enhancers for exposure-based therapy of fear, anxiety and trauma-related disorders. Pharmacol Ther 2014; 149:150-90. [PMID: 25550231 PMCID: PMC4380664 DOI: 10.1016/j.pharmthera.2014.12.004] [Citation(s) in RCA: 272] [Impact Index Per Article: 27.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 12/24/2014] [Indexed: 12/20/2022]
Abstract
Pathological fear and anxiety are highly debilitating and, despite considerable advances in psychotherapy and pharmacotherapy they remain insufficiently treated in many patients with PTSD, phobias, panic and other anxiety disorders. Increasing preclinical and clinical evidence indicates that pharmacological treatments including cognitive enhancers, when given as adjuncts to psychotherapeutic approaches [cognitive behavioral therapy including extinction-based exposure therapy] enhance treatment efficacy, while using anxiolytics such as benzodiazepines as adjuncts can undermine long-term treatment success. The purpose of this review is to outline the literature showing how pharmacological interventions targeting neurotransmitter systems including serotonin, dopamine, noradrenaline, histamine, glutamate, GABA, cannabinoids, neuropeptides (oxytocin, neuropeptides Y and S, opioids) and other targets (neurotrophins BDNF and FGF2, glucocorticoids, L-type-calcium channels, epigenetic modifications) as well as their downstream signaling pathways, can augment fear extinction and strengthen extinction memory persistently in preclinical models. Particularly promising approaches are discussed in regard to their effects on specific aspects of fear extinction namely, acquisition, consolidation and retrieval, including long-term protection from return of fear (relapse) phenomena like spontaneous recovery, reinstatement and renewal of fear. We also highlight the promising translational value of the preclinial research and the clinical potential of targeting certain neurochemical systems with, for example d-cycloserine, yohimbine, cortisol, and L-DOPA. The current body of research reveals important new insights into the neurobiology and neurochemistry of fear extinction and holds significant promise for pharmacologically-augmented psychotherapy as an improved approach to treat trauma and anxiety-related disorders in a more efficient and persistent way promoting enhanced symptom remission and recovery.
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Affiliation(s)
- N Singewald
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria.
| | - C Schmuckermair
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - N Whittle
- Department of Pharmacology and Toxicology, Institute of Pharmacy and CMBI, Leopold-Franzens University of Innsbruck, Innrain 80-82, A-6020 Innsbruck, Austria
| | - A Holmes
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, NIH, Bethesda, MD, USA
| | - K J Ressler
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA, USA
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35
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Jalan-Sakrikar N, Field JR, Klar R, Mattmann M, Gregory KJ, Zamorano R, Engers DW, Bollinger SR, Weaver CD, Days EL, Lewis LM, Utley TJ, Hurtado M, Rigault D, Acher F, Walker AG, Melancon BJ, Wood MR, Lindsley C, Conn PJ, Xiang Z, Hopkins CR, Niswender CM. Identification of positive allosteric modulators VU0155094 (ML397) and VU0422288 (ML396) reveals new insights into the biology of metabotropic glutamate receptor 7. ACS Chem Neurosci 2014; 5:1221-37. [PMID: 25225882 PMCID: PMC4306484 DOI: 10.1021/cn500153z] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2014] [Revised: 09/15/2014] [Indexed: 11/29/2022] Open
Abstract
Metabotropic glutamate receptor 7 (mGlu7) is a member of the group III mGlu receptors (mGlus), encompassed by mGlu4, mGlu6, mGlu7, and mGlu8. mGlu7 is highly expressed in the presynaptic active zones of both excitatory and inhibitory synapses, and activation of the receptor regulates the release of both glutamate and GABA. mGlu7 is thought to be a relevant therapeutic target for a number of neurological and psychiatric disorders, and polymorphisms in the GRM7 gene have been linked to autism, depression, ADHD, and schizophrenia. Here we report two new pan-group III mGlu positive allosteric modulators, VU0155094 and VU0422288, which show differential activity at the various group III mGlus. Additionally, both compounds show probe dependence when assessed in the presence of distinct orthosteric agonists. By pairing studies of these nonselective compounds with a synapse in the hippocampus that expresses only mGlu7, we have validated activity of these compounds in a native tissue setting. These studies provide proof-of-concept evidence that mGlu7 activity can be modulated by positive allosteric modulation, paving the way for future therapeutics development.
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Affiliation(s)
- Nidhi Jalan-Sakrikar
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Julie R. Field
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Rebecca Klar
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Margrith
E. Mattmann
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Karen J. Gregory
- Drug
Discovery Biology, Monash Institute of Pharmaceutical
Sciences, Parkville, VIC 3052, Australia
| | - Rocio Zamorano
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Darren W. Engers
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Sean R. Bollinger
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - C. David Weaver
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Emily L. Days
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - L. Michelle Lewis
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Thomas J. Utley
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Miguel Hurtado
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | | | | | - Adam G. Walker
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Bruce J. Melancon
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Michael R. Wood
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Craig
W. Lindsley
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - P. Jeffrey Conn
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Zixiu Xiang
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Corey R. Hopkins
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
| | - Colleen M. Niswender
- Department of Pharmacology and Vanderbilt Center
for Neuroscience Drug Discovery, Department of Pharmacology and
Vanderbilt Institute of Chemical Biology, and Department of Chemistry, Vanderbilt University, Nashville, Tennessee 37212, United States
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36
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Bukalo O, Pinard CR, Holmes A. Mechanisms to medicines: elucidating neural and molecular substrates of fear extinction to identify novel treatments for anxiety disorders. Br J Pharmacol 2014; 171:4690-718. [PMID: 24835117 DOI: 10.1111/bph.12779] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Revised: 04/28/2014] [Accepted: 05/04/2014] [Indexed: 12/11/2022] Open
Abstract
The burden of anxiety disorders is growing, but the efficacy of available anxiolytic treatments remains inadequate. Cognitive behavioural therapy for anxiety disorders focuses on identifying and modifying maladaptive patterns of thinking and behaving, and has a testable analogue in rodents in the form of fear extinction. A large preclinical literature has amassed in recent years describing the neural and molecular basis of fear extinction in rodents. In this review, we discuss how this work is being harnessed to foster translational research on anxiety disorders and facilitate the search for new anxiolytic treatments. We begin by summarizing the anatomical and functional connectivity of a medial prefrontal cortex (mPFC)-amygdala circuit that subserves fear extinction, including new insights from optogenetics. We then cover some of the approaches that have been taken to model impaired fear extinction and associated impairments with mPFC-amygdala dysfunction. The principal goal of the review is to evaluate evidence that various neurotransmitter and neuromodulator systems mediate fear extinction by modulating the mPFC-amygdala circuitry. To that end, we describe studies that have tested how fear extinction is impaired or facilitated by pharmacological manipulations of dopamine, noradrenaline, 5-HT, GABA, glutamate, neuropeptides, endocannabinoids and various other systems, which either directly target the mPFC-amygdala circuit, or produce behavioural effects that are coincident with functional changes in the circuit. We conclude that there are good grounds to be optimistic that the progress in defining the molecular substrates of mPFC-amygdala circuit function can be effectively leveraged to identify plausible candidates for extinction-promoting therapies for anxiety disorders.
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Affiliation(s)
- Olena Bukalo
- Laboratory of Behavioral and Genomic Neuroscience, National Institute on Alcohol Abuse and Alcoholism, Bethesda, MD, USA
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37
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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]
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38
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Vadasz C, Saito M. New glutamatergic target for alcohol and substance use disorder medications. Psychopharmacology (Berl) 2014; 231:1429-31. [PMID: 24619644 DOI: 10.1007/s00213-014-3496-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2013] [Accepted: 01/29/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Csaba Vadasz
- Nathan Kline Institute, Neurobehavioral Genetics, New York University School of Medicine, Psychiatry, New York, USA,
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39
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Gee CE, Peterlik D, Neuhäuser C, Bouhelal R, Kaupmann K, Laue G, Uschold-Schmidt N, Feuerbach D, Zimmermann K, Ofner S, Cryan JF, van der Putten H, Fendt M, Vranesic I, Glatthar R, Flor PJ. Blocking metabotropic glutamate receptor subtype 7 (mGlu7) via the Venus flytrap domain (VFTD) inhibits amygdala plasticity, stress, and anxiety-related behavior. J Biol Chem 2014; 289:10975-10987. [PMID: 24596089 DOI: 10.1074/jbc.m113.542654] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The metabotropic glutamate receptor subtype 7 (mGlu7) is an important presynaptic regulator of neurotransmission in the mammalian CNS. mGlu7 function has been linked to autism, drug abuse, anxiety, and depression. Despite this, it has been difficult to develop specific blockers of native mGlu7 signaling in relevant brain areas such as amygdala and limbic cortex. Here, we present the mGlu7-selective antagonist 7-hydroxy-3-(4-iodophenoxy)-4H-chromen-4-one (XAP044), which inhibits lateral amygdala long term potentiation (LTP) in brain slices from wild type mice with a half-maximal blockade at 88 nm. There was no effect of XAP044 on LTP of mGlu7-deficient mice, indicating that this pharmacological effect is mGlu7-dependent. Unexpectedly and in contrast to all previous mGlu7-selective drugs, XAP044 does not act via the seven-transmembrane region but rather via a binding pocket localized in mGlu7's extracellular Venus flytrap domain, a region generally known for orthosteric agonist binding. This was shown by chimeric receptor studies in recombinant cell line assays. XAP044 demonstrates good brain exposure and wide spectrum anti-stress and antidepressant- and anxiolytic-like efficacy in rodent behavioral paradigms. XAP044 reduces freezing during acquisition of Pavlovian fear and reduces innate anxiety, which is consistent with the phenotypes of mGlu7-deficient mice, the results of mGlu7 siRNA knockdown studies, and the inhibition of amygdala LTP by XAP044. Thus, we present an mGlu7 antagonist with a novel molecular mode of pharmacological action, providing significant application potential in psychiatry. Modeling the selective interaction between XAP044 and mGlu7's Venus flytrap domain, whose three-dimensional structure is already known, will facilitate future drug development supported by computer-assisted drug design.
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Affiliation(s)
- Christine E Gee
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland,; Center for Molecular Neurobiology Hamburg, University Medical Center Hamburg-Eppendorf, D-20249 Hamburg, Germany
| | - Daniel Peterlik
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Christoph Neuhäuser
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Rochdi Bouhelal
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland
| | - Klemens Kaupmann
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland
| | - Grit Laue
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland
| | - Nicole Uschold-Schmidt
- Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany
| | - Dominik Feuerbach
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland
| | - Kaspar Zimmermann
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland
| | - Silvio Ofner
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland
| | - John F Cryan
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland,; Department of Anatomy and Neuroscience, University of Cork, Cork, Ireland, and
| | - Herman van der Putten
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland
| | - Markus Fendt
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland,; Institute of Pharmacology and Toxicology and Center of Behavioral Brain Sciences, University of Magdeburg, D-39120 Magdeburg, Germany
| | - Ivo Vranesic
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland
| | - Ralf Glatthar
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland,.
| | - Peter J Flor
- Novartis Institutes for BioMedical Research, Novartis AG, CH-4057 Basel, Switzerland,; Faculty of Biology and Preclinical Medicine, Laboratory of Molecular and Cellular Neurobiology, University of Regensburg, D-93053 Regensburg, Germany,.
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40
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Bahi A. Viral-mediated knockdown of mGluR7 in the nucleus accumbens mediates excessive alcohol drinking and increased ethanol-elicited conditioned place preference in rats. Neuropsychopharmacology 2013; 38:2109-19. [PMID: 22781839 PMCID: PMC3773660 DOI: 10.1038/npp.2012.122] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 06/13/2012] [Accepted: 06/14/2012] [Indexed: 11/09/2022]
Abstract
Whether metabotropic glutamate 7 (mGluR7) -activation enhances or diminishes the reinforcing properties of psychostimulants remains unclear. We have previously shown that systemic mGluR7 activation reduced alcohol consumption and preference as well as locomotor-stimulating and rewarding properties of ethanol. In this study, we further examined the contribution of mGluR7 on the effect of ethanol within the nucleus accumbens (NAcc), a neural target for many drugs of abuse. Using short hairpin RNA (shRNA)-expressing lentiviral vectors (LV) to alter locally the activity of mGluR7 in male rats, we have shown that blocking mGluR7 expression increased ethanol consumption and preference in a two-bottle choice drinking paradigm with no effect either on saccharin or on quinine used for taste discrimination. In addition, mGluR7 knockdown increases preference for environments previously paired with low doses of ethanol in the conditioned place preference (CPP) test, as it shifted the dose-response curve for ethanol CPP to the left, indicating alterations in the rewarding effects of alcohol. More importantly, mGluR7 blockade in the dorsal striatum (DS) neither affected ethanol consumption nor ethanol-elicited CPP. These results show that levels of mGluR7 in the NAcc regulate responsiveness to alcohol. Taken together, these findings clearly demonstrate that mGluR7 signaling within the NAcc is a key modulator of functional responses to ethanol and offer an important target for regulating the addictive effects of alcohol.
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Affiliation(s)
- Amine Bahi
- Department of Anatomy, Faculty of Medicine and Health Sciences, United Arab Emirates University, Al Ain, UAE,Department of Anatomy, Faculty of Medicine & Health Sciences, Tawam Medical Campus, United Arab Emirates University, PO Box 17666, Al Ain, UAE, Tel: +971 3 7137 516, Fax: +971 3 7672 033, E-mail:
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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]
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Fendt M, Imobersteg S, Peterlik D, Chaperon F, Mattes C, Wittmann C, Olpe HR, Mosbacher J, Vranesic I, van der Putten H, McAllister KH, Flor PJ, Gee CE. Differential roles of mGlu(7) and mGlu(8) in amygdala-dependent behavior and physiology. Neuropharmacology 2013; 72:215-23. [PMID: 23664812 DOI: 10.1016/j.neuropharm.2013.04.052] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 04/09/2013] [Accepted: 04/18/2013] [Indexed: 11/26/2022]
Abstract
Glutamate transmission and synaptic plasticity in the amygdala are essential for the learning and expression of conditioned fear. Glutamate activates both ionotropic glutamate receptors and eight subtypes of metabotropic glutamate receptors (mGlu1-8). In the present study, we investigated the roles of mGlu7 and mGlu8 in amygdala-dependent behavior and synaptic plasticity. We show that ablation of mGlu7 but not mGlu8 attenuates long-term potentiation (LTP) at thalamo-lateral amygdala (LA) synapses where a strong association between LTP and learning has been demonstrated. mGlu7-deficient mice express a general deficit in conditioned fear whereas mGlu8-deficient mice show a dramatic reduction in contextual fear. The mGlu7 agonist AMN082 reduced thalamo-LA LTP and intra-amygdala administration blocked conditioned fear learning. In contrast, the mGlu8 agonist DCPG decreased synaptic transmission but not LTP at thalamo-LA synapses. Intra-amygdala DCPG selectively reduced the expression of contextual fear but did not affect the acquisition and expression of cued fear. Taken together, these data revealed very different roles for mGlu7 and mGlu8 in amygdala synaptic transmission, fear learning and its expression. These receptors seem promising targets for treating anxiety disorders with different underlying pathologies with exaggerated fear learning (mGlu7) or contextual fear (mGlu8).
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Affiliation(s)
- Markus Fendt
- Novartis Institutes for BioMedical Research, Neuroscience DA, Forum 1, Novartis Campus, CH-4056 Basel, Switzerland.
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Hoyer D, Bartfai T. Neuropeptides and neuropeptide receptors: drug targets, and peptide and non-peptide ligands: a tribute to Prof. Dieter Seebach. Chem Biodivers 2013; 9:2367-87. [PMID: 23161624 DOI: 10.1002/cbdv.201200288] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Indexed: 11/06/2022]
Abstract
The number of neuropeptides and their corresponding receptors has increased steadily over the last fourty years: initially, peptides were isolated from gut or brain (e.g., Substance P, somatostatin), then by targeted mining in specific regions (e.g., cortistatin, orexin in the brain), or by deorphanization of G-protein-coupled receptors (GPCRs; orexin, ghrelin receptors) and through the completion the Human Genome Project. Neuropeptides (and their receptors) have regionally restricted distributions in the central and peripheral nervous system. The neuropeptide signaling is somewhat more distinct spatially than signaling with classical, low-molecular-weight neurotransmitters that are more widely expressed, and, therefore, one assumes that drugs acting at neuropeptide receptors may have more selective pharmacological actions with possibly fewer side effects than drugs acting on glutamatergic, GABAergic, monoaminergic, or cholinergic systems. Neuropeptide receptors, which may have a few or multiple subtypes and splice variants, belong almost exclusively to the GPCR family also known as seven-transmembrane receptors (7TM), a favorite class of drug targets in the pharmaceutical industry. Most neuropeptides are co-stored and co-released with classic neurotransmitters, albeit often only at higher frequencies of stimulation or at bursting activity, thus restricting the neuropeptide signaling to specific circumstances, another reason to assume that neuropeptide drug mimics may have less side effects. Neuropeptides possess a wide spectrum of functions from neurohormone, neurotransmitter to growth factor, but also as key inflammatory mediators. Neuropeptides become 'active' when the nervous system is challenged, e.g., by stress, injury, drug abuse, or neuropsychiatric disorders with genetic, epigenetic, and/or environmental components. The unsuspected number of true neuropeptides and their cognate receptors provides opportunities to identify novel targets for the treatment of both central and peripheral nervous system disorders. Both, receptor subtype-selective antagonists and agonists are being developed, as illustrated by the success of somatostatin agonists, angiotensin, and endothelin antagonists, and the expected clinical applications of NK-1/2/3 (substance P) receptor antagonists, CRF, vasopressin, NPY, neurotensin, orexin antagonists, or neuropeptide receptor modulators; such ligands have efficacy in preclinical or clinical models of pain and neuropsychiatric diseases, such as migraine, chronic/neuropathic pain, anxiety, sleep disorders, depression, and schizophrenia. In addition, both positive and negative allosteric modulators have been described with interesting in vivo activities (e.g., at galanin receptors). The field has become more complex now that an increasing number of heteromeric neuropeptide receptors are described, e.g., ghrelin receptors with 5-HT(2C) or dopamine D(1), D(2) receptors. At long last, structure-based drug discovery can now be envisaged with confidence, since crystal or solution structure of GPCRs and GPCR-ligand complexes, including peptide receptors, are published almost on a monthly basis. Finally, although most compounds acting at peptide receptors are still peptidomimetics, the last decade has seen the emergence of low-molecular-weight nonpeptide ligands (e.g., for orexin, ghrelin, or neurokinin receptors), and surprising progress has been made with β- and γ-peptides as very stable and potent mimetics of, e.g., somatostatin (SRIF), where the native SRIF has a half-life limited to 2-3 min. This last point will be illustrated more specifically, as we have had a long-standing collaboration with Prof. D. Seebach to whom this review is dedicated at the occasion of his 75th birthday.
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Affiliation(s)
- Daniel Hoyer
- Department of Pharmacology, Faculty of Medicine, Dentistry and Health Sciences, The University of Melbourne, Parkville, Victoria 3010, Australia.
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O'Connor RM, Thakker DR, Schmutz M, van der Putten H, Hoyer D, Flor PJ, Cryan JF. Adult siRNA-induced knockdown of mGlu7 receptors reduces anxiety in the mouse. Neuropharmacology 2013; 72:66-73. [PMID: 23603202 DOI: 10.1016/j.neuropharm.2013.03.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Revised: 03/07/2013] [Accepted: 03/12/2013] [Indexed: 10/26/2022]
Abstract
Our knowledge regarding the molecular pathophysiology underlying anxiety disorders remains incomplete. Increasing evidence points to a role of glutamate in anxiety. The group III metabotropic glutamate receptors (mGlu4, mGlu6, mGlu7 and mGlu8 receptors) remain the least investigated glutamate receptor subtypes partially due to a delay in the development of specific pharmacological tools. Early work using knockout animals and pharmacological tools aimed at investigating the role of mGlu7 receptor in the pathophysiology of anxiety disorders has yielded exciting yet not always consistent results. To further investigate the role this receptor plays in anxiety-like behaviour, we knocked down mGlu7 receptor mRNA levels in the adult mouse brain using siRNA delivered via an osmotic minipump. This reduced anxiety-like behaviour in the light-dark box coupled with an attenuation of stress-induced hyperthermia (SIH) and a reduction of the acoustic startle response (ASRs) in the fear-potentiated startle paradigm (FPS). These effects on anxiety-like behaviour were independent of any impairment of locomotor activity and surprisingly, no behavioural changes were observed in the forced swim test (FST), which is in contrast to mGlu7 receptor knockout animals. Furthermore, the previously reported epilepsy-prone phenotype seen in mGlu7 receptor knockout animals was not observed following siRNA-induced knockdown of the receptor. These data suggest targeting mGlu7 receptors with selective antagonist drugs may be an effective and safe strategy for the treatment of anxiety disorders.
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Affiliation(s)
- Richard M O'Connor
- Department of Anatomy & Neuroscience, University College Cork, Cork, Ireland
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Ullmer C, Zoffmann S, Bohrmann B, Matile H, Lindemann L, Flor P, Malherbe P. Functional monoclonal antibody acts as a biased agonist by inducing internalization of metabotropic glutamate receptor 7. Br J Pharmacol 2013; 167:1448-66. [PMID: 22747985 DOI: 10.1111/j.1476-5381.2012.02090.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE The mGlu(7) receptors are strategically located at the site of vesicle fusion where they modulate the release of the main excitatory and inhibitory neurotransmitters. Consequently, they are implicated in the underlying pathophysiology of CNS diseases such as epilepsy and stress-related psychiatric disorders. Here, we characterized a selective, potent and functional anti-mGlu(7) monoclonal antibody, MAB1/28, that triggers receptor internalization. EXPERIMENTAL APPROACH MAB1/28's activity was investigated using Western blot and direct immunofluorescence on live cells, in vitro pharmacology by functional cAMP and [(35) S]-GTPγ binding assays, the kinetics of IgG-induced internalization by image analysis, and the activation of the ERK1/2 by elisa. KEY RESULTS mGlu(7) /mGlu(6) chimeric studies located the MAB1/28 binding site at the extracellular amino-terminus of mGlu(7) . MAB1/28 potently antagonized both orthosteric and allosteric agonist-induced inhibition of cAMP accumulation. The potency of the antagonistic actions was similar to the potency in triggering receptor internalization. The internalization mechanism occurred via a pertussis toxin-insensitive pathway and did not require Gα(i) protein activation. MAB1/28 activated ERK1/2 with potency similar to that for receptor internalization. The requirement of a bivalent receptor binding mode for receptor internalizations suggests that MAB1/28 modulates mGlu(7) dimers. CONCLUSIONS AND IMPLICATIONS We obtained evidence for an allosteric-biased agonist activity triggered by MAB1/28, which activates a novel IgG-mediated GPCR internalization pathway that is not utilized by small molecule, orthosteric or allosteric agonists. Thus, MAB1/28 provides an invaluable biological tool for probing mGlu(7) function and selective activation of its intracellular trafficking.
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Affiliation(s)
- C Ullmer
- DTA CV and Metabolism, Discovery Research CV & Metabolic Diseases, F. Hoffmann-La Roche AG, pRED, Pharma Research & Early Development, Basel, Switzerland.
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Park S, Jung SW, Kim BN, Cho SC, Shin MS, Kim JW, Yoo HJ, Cho DY, Chung US, Son JW, Kim HW. Association between the GRM7 rs3792452 polymorphism and attention deficit hyperacitiveity disorder in a Korean sample. Behav Brain Funct 2013; 9:1. [PMID: 23295062 PMCID: PMC3680053 DOI: 10.1186/1744-9081-9-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 12/19/2012] [Indexed: 12/15/2022] Open
Abstract
Background The purpose of this study was to investigate the association between the ionotropic and glutamate receptors, N-methyl D-asparate 2A (GRIN2A) and 2B (GRIN2B), and the metabotropic glutamate receptor mGluR7 (GRM7) gene polymorphisms and attention-deficit hyperactivity disorder (ADHD) in Korean population. Methods We conducted a case–control analysis of 202 ADHD subjects and 159 controls, performed a transmission disequilibrium test (TDT) on 149 trios, and compared scores from the continuous performance test (CPT), the Children’s Depression Inventory (CDI), and the State-Trait Anxiety Inventory for Children (STAIC) according to the genotype of the glutamate receptor genes. Results There were no significant differences in the genotype or allele frequencies of the GRIN2A rs8049651, GRIN2B rs2284411, or GRM7 rs37952452 polymorphisms between the ADHD and control groups. For 148 ADHD trios, the TDT analysis also showed no preferential transmission of the GRIN2A rs8049651 or GRIN2B rs2284411 polymorphisms. However, the TDT analysis of the GRM7 rs3792452 polymorphism showed biased transmission of the G allele (χ2 = 4.67, p = 0.031). In the ADHD probands, the subjects with GG genotype in the GRM7 rs37952452 polymorphism had higher mean T-scores for omission errors on the CPT than did those with the GA or AA genotype (t = 3.38, p = 0.001). In addition, the ADHD subjects who were homozygous for the G allele in the GRM7 rs37952452 polymorphism had higher STAIC-T (t = 5.52, p < 0.001) and STAIC-S (t = 2.74, p = 0.007) scores than did those with the GA or AA genotype. Conclusions These results provide preliminary evidence of an association between the GRM7 rs37952452 polymorphism and selective attention deficit and anxiety found within the Korean ADHD population.
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Affiliation(s)
- Subin Park
- Department of Child and Adolescent Psychiatry, Seoul National University Hospital, Seoul, Korea
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Whittle N, Schmuckermair C, Gunduz Cinar O, Hauschild M, Ferraguti F, Holmes A, Singewald N. Deep brain stimulation, histone deacetylase inhibitors and glutamatergic drugs rescue resistance to fear extinction in a genetic mouse model. Neuropharmacology 2013; 64:414-23. [PMID: 22722028 PMCID: PMC3474950 DOI: 10.1016/j.neuropharm.2012.06.001] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/31/2012] [Accepted: 06/06/2012] [Indexed: 12/16/2022]
Abstract
Anxiety disorders are characterized by persistent, excessive fear. Therapeutic interventions that reverse deficits in fear extinction represent a tractable approach to treating these disorders. We previously reported that 129S1/SvImJ (S1) mice show no extinction learning following normal fear conditioning. We now demonstrate that weak fear conditioning does permit fear reduction during massed extinction training in S1 mice, but reveals specific deficiency in extinction memory consolidation/retrieval. Rescue of this impaired extinction consolidation/retrieval was achieved with d-cycloserine (N-methly-d-aspartate partial agonist) or MS-275 (histone deacetylase (HDAC) inhibitor), applied after extinction training. We next examined the ability of different drugs and non-pharmacological manipulations to rescue the extreme fear extinction deficit in S1 following normal fear conditioning with the ultimate aim to produce low fear levels in extinction retrieval tests. Results showed that deep brain stimulation (DBS) by applying high frequency stimulation to the nucleus accumbens (ventral striatum) during extinction training, indeed significantly reduced fear during extinction retrieval compared to sham stimulation controls. Rescue of both impaired extinction acquisition and deficient extinction consolidation/retrieval was achieved with prior extinction training administration of valproic acid (a GABAergic enhancer and HDAC inhibitor) or AMN082 [metabotropic glutamate receptor 7 (mGlu7) agonist], while MS-275 or PEPA (AMPA receptor potentiator) failed to affect extinction acquisition in S1 mice. Collectively, these data identify potential beneficial effects of DBS and various drug treatments, including those with HDAC inhibiting or mGlu7 agonism properties, as adjuncts to overcome treatment resistance in exposure-based therapies. This article is part of a Special Issue entitled 'Cognitive Enhancers'.
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Affiliation(s)
- Nigel Whittle
- Department of Pharmacology and Toxicology, Institute of Pharmacy and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innrain 80 - 82/III, A-6020 Innsbruck, Austria.
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Julio-Pieper M, O'Connor RM, Dinan TG, Cryan JF. Regulation of the brain-gut axis by group III metabotropic glutamate receptors. Eur J Pharmacol 2012; 698:19-30. [PMID: 23123053 DOI: 10.1016/j.ejphar.2012.10.027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 10/11/2012] [Accepted: 10/22/2012] [Indexed: 01/14/2023]
Abstract
L-glutamate is produced by a great variety of peripheral tissues in both health and disease. Like other components of the glutamatergic system, metabotropic glutamate (mGlu) receptors also have a widespread distribution outside the central nervous system (CNS). In particular, group III mGlu receptors have been recently found in human stomach and colon revealing an extraordinary potential for these receptors in the treatment of peripheral disorders, including gastrointestinal dysfunction. The significance of these findings is that pharmacological tools originally designed for mGlu receptors in the CNS may also be directed towards new disease targets in the periphery. Targeting mGlu receptors can also be beneficial in the treatment of disorders involving central components together with gastrointestinal dysfunction, such as irritable bowel syndrome, which can be co-morbid with anxiety and depression. Conversely, the development of more specific therapeutic approaches for mGlu ligands both centrally as in the gut will depend on the elucidation of tissue-specific elements in mGlu receptor signalling.
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Affiliation(s)
- Marcela Julio-Pieper
- Instituto de Química, Facultad de Ciencias, Pontificia Universidad Católica de Valparaíso, Av Universidad 330, Curauma, Valparaíso, Chile.
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O’Mahony AM, Godinho BMDC, Ogier J, Devocelle M, Darcy R, Cryan JF, O’Driscoll CM. Click-modified cyclodextrins as nonviral vectors for neuronal siRNA delivery. ACS Chem Neurosci 2012; 3:744-52. [PMID: 23077718 DOI: 10.1021/cn3000372] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 08/03/2012] [Indexed: 12/27/2022] Open
Abstract
RNA interference (RNAi) holds great promise as a strategy to further our understanding of gene function in the central nervous system (CNS) and as a therapeutic approach for neurological and neurodegenerative diseases. However, the potential for its use is hampered by the lack of siRNA delivery vectors which are both safe and highly efficient. Cyclodextrins have been shown to be efficient and low toxicity gene delivery vectors in various cell types in vitro. However, to date, they have not been exploited for delivery of oligonucleotides to neurons. To this end, a modified β-cyclodextrin (CD) vector was synthesized, which complexed siRNA to form cationic nanoparticles of less than 200 nm in size. Furthermore, it conferred stability in serum to the siRNA cargo. The in vitro performance of the CD in both immortalized hypothalamic neurons and primary hippocampal neurons was evaluated. The CD facilitated high levels of intracellular delivery of labeled siRNA, while maintaining at least 80% cell viability. Significant gene knockdown was achieved, with a reduction in luciferase expression of up to 68% and a reduction in endogenous glyceraldehyde phosphate dehydrogenase (GAPDH) expression of up to 40%. To our knowledge, this is the first time that a modified CD has been used as a safe and efficacious vector for siRNA delivery into neuronal cells.
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Affiliation(s)
- A. M. O’Mahony
- Pharmacodelivery Group, School
of Pharmacy, University College Cork, Ireland
| | - B. M. D. C. Godinho
- Pharmacodelivery Group, School
of Pharmacy, University College Cork, Ireland
| | - J. Ogier
- Centre for Synthesis and Chemical
Biology, UCD Conway Institute, University College Dublin, Ireland
| | - M. Devocelle
- Department of Pharmaceutical & Medicinal Chemistry, Royal College of Surgeons in Ireland, Dublin 2, Ireland
| | - R. Darcy
- Centre for Synthesis and Chemical
Biology, UCD Conway Institute, University College Dublin, Ireland
| | - J. F. Cryan
- Department
of Anatomy and Neuroscience, University College Cork, Ireland
| | - C. M. O’Driscoll
- Pharmacodelivery Group, School
of Pharmacy, University College Cork, Ireland
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Davis MJ, Iancu OD, Acher FC, Stewart BM, Eiwaz MA, Duvoisin RM, Raber J. Role of mGluR4 in acquisition of fear learning and memory. Neuropharmacology 2012; 66:365-72. [PMID: 22884897 DOI: 10.1016/j.neuropharm.2012.07.038] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2012] [Revised: 07/16/2012] [Accepted: 07/20/2012] [Indexed: 11/28/2022]
Abstract
Group III metabotropic glutamate receptors (mGluRs), which are generally located presynaptically, modulate synaptic transmission by regulating neurotransmitter release. Previously we showed enhanced amygdala-dependent cued fear conditioning in mGluR4(-/-) mice 24 h following training involving two tone-shock pairings. In this study, we assessed the effects of modulating mGluR4 signaling on acquisition and extinction of conditioned fear. mGluR4(-/-) and wild-type female and male mice received 10 tone-shock pairings during training. Compared to wild-type mice, mGluR4(-/-) mice showed enhanced acquisition and extinction of cued fear. Next, we assessed whether acute pharmacological stimulation of mGluR4 with the specific orthosteric mGluR4 agonist LSP1-2111 also affects acquisition and extinction of cued fear. Consistent with the enhanced acquisition of cued fear in mGluR4(-/-), LSP1-2111, at 2.5 and 5 mg/kg, inhibited acquisition of cued fear conditioning in wild-type male mice. The drug's effect on extinction was less clear and only a subtle effect was seen at 5 mg/kg. Finally, analysis of microarray data of amygdala tissues from mGluR4(-/-) versus wild-type and from wild-type mice treated with a mGluR4 agonist versus saline revealed a significant overlap in pattern of gene expression. Together, these data support a role for mGluR4 signaling in acquisition of fear learning and memory. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- Matthew J Davis
- Department of Behavioral Neuroscience, Oregon Health & Science University, Portland, OR, USA
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