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Xu Y, Chen G, Cui Z, Wang Y, Wang W, Blank I, Zhang Y, Xu C, Yang Y, Liu Y. Novel Umami Peptides from Mushroom ( Agaricus bisporus) and Their Umami Enhancing Effect via Virtual Screening and Molecular Simulation. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2024. [PMID: 38608250 DOI: 10.1021/acs.jafc.3c04608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2024]
Abstract
This study aimed to identify novel umami peptides in Agaricus bisporus and investigate their umami enhancing effect. We virtually screened 155 potential umami peptides from the ultrasound-assisted A. bisporus hydrolysate according to Q values, iUmami-SCM, Umami_YYDS, and Tastepeptides_DM models, and molecular docking. Five peptides (AGKNTNGSQF, DEAVARGATF, REESDFQSSF, SEETTTGVHH, and WNNDAFQSSTN) were synthesized for sensory evaluation and kinetic analysis. The result showed that the umami thresholds of the five peptides were in the range of 0.21-0.40 mmol/L. Notably, REESDFQSSF, SEETTTGVHH, and WNNDAFQSSTN had low dissociation constant (KD) values and high affinity for the T1R1-VFT receptor. The enhancing effect of the three peptides with MSG or IMP was investigated by sensory evaluation, kinetic analysis, and molecular dynamics simulations. In stable complexes, ARG_277 in T1R1 played a major role in umami peptide binding to T1R1-VFT. These results provide a theoretical basis for future screening of umami peptides and improving the umami taste of food containing mushrooms.
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Affiliation(s)
- Yeling Xu
- Department of Food Science & Technology, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, PR China
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Gaole Chen
- Department of Food Science & Technology, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Zhiyong Cui
- Department of Food Science & Technology, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Yueming Wang
- Department of Food Science & Technology, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Wenli Wang
- Department of Food Science & Technology, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, PR China
| | - Imre Blank
- Zhejiang Yiming Food Co., Ltd., Jiuting Center Huting North Street No.199, Shanghai 201600, China
| | - Yin Zhang
- Key Laboratory of Meat Processing of Sichuan, Chengdu University, Chengdu 610106, China
| | - Changhua Xu
- College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China
| | - Yan Yang
- Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Shanghai 201403, China
| | - Yuan Liu
- Department of Food Science & Technology, School of Agriculture & Biology, Shanghai Jiao Tong University, Shanghai 200240, PR China
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2
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Freitas GA, Niswender CM. GRM7 gene mutations and consequences for neurodevelopment. Pharmacol Biochem Behav 2023; 225:173546. [PMID: 37003303 PMCID: PMC10192299 DOI: 10.1016/j.pbb.2023.173546] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 03/22/2023] [Accepted: 03/28/2023] [Indexed: 04/03/2023]
Abstract
The metabotropic glutamate receptor 7 (mGlu7), encoded by the GRM7 gene in humans, is a presynaptic, G protein-coupled glutamate receptor that is essential for modulating neurotransmission. Mutations in or reduced expression of GRM7 have been identified in different genetic neurodevelopmental disorders (NDDs), and rare biallelic missense variants have been proposed to underlie a subset of NDDs. Clinical GRM7 variants have been associated with a range of symptoms consistent with neurodevelopmental molecular features, including hypomyelination, brain atrophy and defects in axon outgrowth. Here, we review the newest findings regarding the cellular and molecular defects caused by GRM7 variants in NDD patients.
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Affiliation(s)
- Geanne A Freitas
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America
| | - Colleen M Niswender
- Department of Pharmacology and Warren Center for Neuroscience Drug Discovery, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Brain Institute, Vanderbilt University, Nashville, TN 37212, United States of America; Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, United States of America.
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3
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Leemann S, Kleinlogel S. Functional optimization of light-activatable Opto-GPCRs: Illuminating the importance of the proximal C-terminus in G-protein specificity. Front Cell Dev Biol 2023; 11:1053022. [PMID: 36936685 PMCID: PMC10014536 DOI: 10.3389/fcell.2023.1053022] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 02/14/2023] [Indexed: 03/05/2023] Open
Abstract
Introduction: G-protein coupled receptors (GPCRs) are the largest family of human receptors that transmit signals from natural ligands and pharmaceutical drugs into essentially every physiological process. One main characteristic of G-protein coupled receptors is their ability to specifically couple with different families of G-proteins, thereby triggering specific downstream signaling pathways. While an abundance of structural information is available on G-protein coupled receptorn interactions with G-proteins, little is known about the G-protein coupled receptor domains functionally mediating G-protein specificity, in particular the proximal C-terminus, the structure which cannot be predicted with high confidentiality due to its flexibility. Methods: In this study, we exploited OptoGPCR chimeras between lightgated G-protein coupled receptors (opsins) and ligand-gated G-protein coupled receptors to systematically investigate the involvement of the C-terminus steering G-protein specificity. We employed rhodopsin-beta2-adrenoceptor and melanopsin-mGluR6 chimeras in second messenger assays and developed structural models of the chimeras. Results: We discovered a dominant role of the proximal C-terminus, dictating G-protein selectivity in the melanopsin-mGluR6 chimera, whereas it is the intracellular loop 3, which steers G-protein tropism in the rhodopsin-beta2-adrenoceptor. From the functional results and structural predictions, melanopsin and mGluR6 use a different mechanism to bovine rhodopsin and b2AR to couple to a selective G-protein. Discussion: Collectively, this work adds knowledge to the G-protein coupled receptor domains mediating G-protein selectivity, ultimately paving the way to optogenetically elicited specific G-protein signaling on demand.
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Caniceiro AB, Bueschbell B, Schiedel AC, Moreira IS. Class A and C GPCR Dimers in Neurodegenerative Diseases. Curr Neuropharmacol 2022; 20:2081-2141. [PMID: 35339177 PMCID: PMC9886835 DOI: 10.2174/1570159x20666220327221830] [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: 09/14/2021] [Revised: 02/21/2022] [Accepted: 03/23/2022] [Indexed: 11/22/2022] Open
Abstract
Neurodegenerative diseases affect over 30 million people worldwide with an ascending trend. Most individuals suffering from these irreversible brain damages belong to the elderly population, with onset between 50 and 60 years. Although the pathophysiology of such diseases is partially known, it remains unclear upon which point a disease turns degenerative. Moreover, current therapeutics can treat some of the symptoms but often have severe side effects and become less effective in long-term treatment. For many neurodegenerative diseases, the involvement of G proteincoupled receptors (GPCRs), which are key players of neuronal transmission and plasticity, has become clearer and holds great promise in elucidating their biological mechanism. With this review, we introduce and summarize class A and class C GPCRs, known to form heterodimers or oligomers to increase their signalling repertoire. Additionally, the examples discussed here were shown to display relevant alterations in brain signalling and had already been associated with the pathophysiology of certain neurodegenerative diseases. Lastly, we classified the heterodimers into two categories of crosstalk, positive or negative, for which there is known evidence.
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Affiliation(s)
- Ana B. Caniceiro
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Beatriz Bueschbell
- PhD Programme in Experimental Biology and Biomedicine, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão, 3030-789 Coimbra, Portugal; ,These authors contributed equally to this work.
| | - Anke C. Schiedel
- Department of Pharmaceutical & Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany;
| | - Irina S. Moreira
- University of Coimbra, Department of Life Sciences, Calçada Martim de Freitas, 3000-456 Coimbra, Portugal; ,Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal,Address correspondence to this author at the Center for Neuroscience and Cell Biology, Center for Innovative Biomedicine and Biotechnology, 3004-504 Coimbra, Portugal; E-mail:
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5
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Qi L, Gao X, Pan D, Sun Y, Cai Z, Xiong Y, Dang Y. Research progress in the screening and evaluation of umami peptides. Compr Rev Food Sci Food Saf 2022; 21:1462-1490. [PMID: 35201672 DOI: 10.1111/1541-4337.12916] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 12/22/2021] [Accepted: 01/03/2022] [Indexed: 12/22/2022]
Abstract
Umami is an important element affecting food taste, and the development of umami peptides is a topic of interest in food-flavoring research. The existing technology used for traditional screening of umami peptides is time-consuming and labor-intensive, making it difficult to meet the requirements of high-throughput screening, which limits the rapid development of umami peptides. The difficulty in performing a standard measurement of umami intensity is another problem that restricts the development of umami peptides. The existing methods are not sensitive and specific, making it difficult to achieve a standard evaluation of umami taste. This review summarizes the umami receptors and umami peptides, focusing on the problems restricting the development of umami peptides, high-throughput screening, and establishment of evaluation standards. The rapid screening of umami peptides was realized based on molecular docking technology and a machine learning method, and the standard evaluation of umami could be realized with a bionic taste sensor. The progress of rapid screening and evaluation methods significantly promotes the study of umami peptides and increases its application in the seasoning industry.
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Affiliation(s)
- Lulu Qi
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of AgroProducts, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang, China
| | - Xinchang Gao
- Department of Chemistry, Tsinghua University, Beijing, China
| | - Daodong Pan
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of AgroProducts, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang, China.,National R&D Center for Freshwater Fish Processing, Jiangxi Normal University, Nanchang, Jiangxi, China
| | - Yangying Sun
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of AgroProducts, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang, China
| | - Zhendong Cai
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of AgroProducts, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang, China
| | - Yongzhao Xiong
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of AgroProducts, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang, China
| | - Yali Dang
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of AgroProducts, College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang, China
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6
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Jang J, Kim SK, Guthrie B, Goddard WA. Synergic Effects in the Activation of the Sweet Receptor GPCR Heterodimer for Various Sweeteners Predicted Using Molecular Metadynamics Simulations. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:12250-12261. [PMID: 34613740 DOI: 10.1021/acs.jafc.1c03779] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
The sweet taste is elicited by activation of the TAS1R2/1R3 heterodimer G protein-coupled receptor. This is a therapeutic target for treatment of obesity and metabolic dysfunctions. Sweetener blends provide attractive strategies to lower the sugar level while preserving the attractive taste of food. To understand the synergic effect of various sweetener blend combinations of artificial and natural sweeteners, we carried out our molecular dynamics studies using predicted structures of the TAS1R2/1R3 heterodimer and predicted structures for the sweeteners. We used as a measure of activation the intracellular ionic lock distance between transmembrane helices 3 and 6 of TAS1R3. We find that full synergic combinations [rebaudioside A (Reb-A)/acesulfame K and Reb-A/sucralose] and partial synergic combinations (sucralose/acesulfame K) show significantly more negative changes in the free energy compared to single-ligand cases, while a pair known to be suppressive (saccharin and acesulfame K) shows significantly less changes than for the single-ligand case. This study provides an atomistic understanding of the mechanism for synergy and identifies new combinations of sweeteners to reduce the caloric content for treating diseases.
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Affiliation(s)
- Jaewan Jang
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - Soo-Kyung Kim
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
| | - Brian Guthrie
- Cargill Global Core Research, Wayzata, Minnesota 55391, United States
| | - William A Goddard
- Materials and Process Simulation Center (139-74), California Institute of Technology, Pasadena, California 91125, United States
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7
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Singh DR, Pandey K, Mishra AK, Pandey P, Vivcharuk V. Glutamate binding triggers monomerization of unliganded mGluR2 dimers. Arch Biochem Biophys 2020; 697:108632. [PMID: 33075300 DOI: 10.1016/j.abb.2020.108632] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/01/2020] [Accepted: 10/14/2020] [Indexed: 11/16/2022]
Abstract
The Metabotropic glutamate receptor 2 (mGluR2) is involved in several neurological and psychiatric disorders and is an attractive drug target. It is believed to form a strict dimer and the dimeric assembly is necessary for glutamate induced activation. Although many studies have focused on glutamate induced conformational changes, the dimerization propensity of mGluR2 with and without glutamate has never been investigated. Also, the role of the unstructured loop in dimerization of mGluR2 is not clear. Here, using Forster Resonance Energy Transfer (FRET) based assay in live cells we show that mGluR2 does not form a "strict dimer" rather it exists in a dynamic monomer-dimer equilibrium. The unstructured loop moderately destabilizes the dimers. Furthermore, binding of glutamate to mGluR2 induces conformational change that promotes monomerization of mGluR2. In the absence of an unstructured loop, mGluR2 neither undergoes conformational change nor monomerizes upon binding to glutamate.
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Affiliation(s)
- Deo R Singh
- Department of Biochemistry, Weill Cornell Medical College, NYC, NY, USA; Department of Cell and Molecular Physiology, Stritch School of Medicine, Maywood, IL, USA; Department of Oncology, University of Wisconsin, Madison, WI, USA.
| | - Kalpana Pandey
- Department of Biochemistry, Weill Cornell Medical College, NYC, NY, USA; Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati, Assam, India.
| | - Ashish K Mishra
- Cell and Developmental Biology Center, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA
| | - Pankaj Pandey
- Department of Zoology, Brahmanand College, Kanpur, UP, India
| | - Victor Vivcharuk
- Department of Biochemistry, Weill Cornell Medical College, NYC, NY, USA
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8
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Odoemelam CS, Percival B, Wallis H, Chang MW, Ahmad Z, Scholey D, Burton E, Williams IH, Kamerlin CL, Wilson PB. G-Protein coupled receptors: structure and function in drug discovery. RSC Adv 2020; 10:36337-36348. [PMID: 35517958 PMCID: PMC9057076 DOI: 10.1039/d0ra08003a] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/22/2020] [Indexed: 12/13/2022] Open
Abstract
The G-protein coupled receptors (GPCRs) superfamily comprise similar proteins arranged into families or classes thus making it one of the largest in the mammalian genome. GPCRs take part in many vital physiological functions making them targets for numerous novel drugs. GPCRs share some distinctive features, such as the seven transmembrane domains, they also differ in the number of conserved residues in their transmembrane domain. Here we provide an introductory and accessible review detailing the computational advances in GPCR pharmacology and drug discovery. An overview is provided on family A-C GPCRs; their structural differences, GPCR signalling, allosteric binding and cooperativity. The dielectric constant (relative permittivity) of proteins is also discussed in the context of site-specific environmental effects.
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Affiliation(s)
| | - Benita Percival
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Helen Wallis
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Ming-Wei Chang
- Nanotechnology and Integrated Bioengineering Centre, University of Ulster Jordanstown Campus Newtownabbey BT37 0QB Northern Ireland UK
| | - Zeeshan Ahmad
- De Montfort University The Gateway Leicester LE1 9BH UK
| | - Dawn Scholey
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Emily Burton
- Nottingham Trent University 50 Shakespeare St Nottingham NG1 4FQ UK
| | - Ian H Williams
- Department of Chemistry, University of Bath Claverton Down Bath BA1 7AY UK
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9
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Evenseth LSM, Gabrielsen M, Sylte I. The GABA B Receptor-Structure, Ligand Binding and Drug Development. Molecules 2020; 25:molecules25133093. [PMID: 32646032 PMCID: PMC7411975 DOI: 10.3390/molecules25133093] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 07/02/2020] [Accepted: 07/06/2020] [Indexed: 11/17/2022] Open
Abstract
The γ-aminobutyric acid (GABA) type B receptor (GABAB-R) belongs to class C of the G-protein coupled receptors (GPCRs). Together with the GABAA receptor, the receptor mediates the neurotransmission of GABA, the main inhibitory neurotransmitter in the central nervous system (CNS). In recent decades, the receptor has been extensively studied with the intention being to understand pathophysiological roles, structural mechanisms and develop drugs. The dysfunction of the receptor is linked to a broad variety of disorders, including anxiety, depression, alcohol addiction, memory and cancer. Despite extensive efforts, few compounds are known to target the receptor, and only the agonist baclofen is approved for clinical use. The receptor is a mandatory heterodimer of the GABAB1 and GABAB2 subunits, and each subunit is composed of an extracellular Venus Flytrap domain (VFT) and a transmembrane domain of seven α-helices (7TM domain). In this review, we briefly present the existing knowledge about the receptor structure, activation and compounds targeting the receptor, emphasizing the role of the receptor in previous and future drug design and discovery efforts.
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Affiliation(s)
- Linn Samira Mari Evenseth
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Mari Gabrielsen
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
| | - Ingebrigt Sylte
- Molecular Pharmacology and Toxicology, Department of Medical Biology, Faculty of Health Sciences, UiT The Arctic University of Norway, NO-9037 Tromsø, Norway
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10
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Saikia S, Bordoloi M, Sarmah R. Established and In-trial GPCR Families in Clinical Trials: A Review for Target Selection. Curr Drug Targets 2020; 20:522-539. [PMID: 30394207 DOI: 10.2174/1389450120666181105152439] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 08/28/2018] [Accepted: 10/22/2018] [Indexed: 12/14/2022]
Abstract
The largest family of drug targets in clinical trials constitute of GPCRs (G-protein coupled receptors) which accounts for about 34% of FDA (Food and Drug Administration) approved drugs acting on 108 unique GPCRs. Factors such as readily identifiable conserved motif in structures, 127 orphan GPCRs despite various de-orphaning techniques, directed functional antibodies for validation as drug targets, etc. has widened their therapeutic windows. The availability of 44 crystal structures of unique receptors, unexplored non-olfactory GPCRs (encoded by 50% of the human genome) and 205 ligand receptor complexes now present a strong foundation for structure-based drug discovery and design. The growing impact of polypharmacology for complex diseases like schizophrenia, cancer etc. warrants the need for novel targets and considering the undiscriminating and selectivity of GPCRs, they can fulfill this purpose. Again, natural genetic variations within the human genome sometimes delude the therapeutic expectations of some drugs, resulting in medication response differences and ADRs (adverse drug reactions). Around ~30 billion US dollars are dumped annually for poor accounting of ADRs in the US alone. To curb such undesirable reactions, the knowledge of established and currently in clinical trials GPCRs families can offer huge understanding towards the drug designing prospects including "off-target" effects reducing economical resource and time. The druggability of GPCR protein families and critical roles played by them in complex diseases are explained. Class A, class B1, class C and class F are generally established family and GPCRs in phase I (19%), phase II(29%), phase III(52%) studies are also reviewed. From the phase I studies, frizzled receptors accounted for the highest in trial targets, neuropeptides in phase II and melanocortin in phase III studies. Also, the bioapplications for nanoparticles along with future prospects for both nanomedicine and GPCR drug industry are discussed. Further, the use of computational techniques and methods employed for different target validations are also reviewed along with their future potential for the GPCR based drug discovery.
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Affiliation(s)
- Surovi Saikia
- Natural Products Chemistry Group, CSIR North East Institute of Science & Technology, Jorhat-785006, Assam, India
| | - Manobjyoti Bordoloi
- Natural Products Chemistry Group, CSIR North East Institute of Science & Technology, Jorhat-785006, Assam, India
| | - Rajeev Sarmah
- Allied Health Sciences, Assam Down Town University, Panikhaiti, Guwahati 781026, Assam, India
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11
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Zhang Y, Liu C, Zhang L, Zhou W, Yu S, Yi R, Luo D, Fu X. Effects of Propofol on Electrical Synaptic Strength in Coupling Reticular Thalamic GABAergic Parvalbumin-Expressing Neurons. Front Neurosci 2020; 14:364. [PMID: 32410945 PMCID: PMC7198707 DOI: 10.3389/fnins.2020.00364] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 03/25/2020] [Indexed: 12/17/2022] Open
Abstract
Electrical synapses between neurons exhibit a high degree of plasticity, which makes critical contributions to neuronal communication. The GABAergic parvalbumin-expressing (PV+) neurons in the thalamic reticular nucleus (TRN) interact with each other through electrical and chemical synapses. Plasticity of electrical synaptic transmission in TRN plays a key role in regulating thalamocortical and corticothalamic circuits and even the formation of consciousness. We here examined the effects of propofol, a commonly used general anesthetic agent, on the strength of electrical synapses between TRN PV+ neurons by fluorescence-guided patch-clamp recording and pharmacological methods. Results show that 100 μM propofol reduced the electrical synaptic strength between TRN PV+ neurons. Notably, the propofol-induced depression of electrical synaptic strength between TRN PV+ neurons was diminished by saclofen (10 μM, antagonist of GABAB receptors), but not blocked by gabazine (10 μM, antagonist of GABAA receptors). Application of baclofen (10 μM, agonist of GABAB receptors), similar to propofol, also reduced the electrical synaptic strength between TRN PV+ neurons. Moreover, the propofol-induced depression of electrical synaptic strength between TRN PV+ neurons was abolished by 9-CPA (100 μM, specific adenylyl cyclase inhibitor), and by KT5720 (1 μM, selective inhibitor of PKA). Our findings indicate that propofol acts on metabotropic GABAB receptors, resulting in a depression of electrical synaptic transmission of coupled TRN PV+ neurons, which is mediated by the adenylyl cyclase-cAMP-PKA signaling pathway. Our findings also imply that propofol may change the thalamocortical communication via inducing depression of electrical synaptic strength in the TRN.
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Affiliation(s)
- Yu Zhang
- Department of Anesthesiology, Affiliated Hospital of Zunyi Medical University, Guizhou, China.,Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou, China
| | - Chengxi Liu
- Guizhou Key Laboratory of Brain Science, Zunyi Medical University, Guizhou, China
| | - Lin Zhang
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou, China
| | - Wenjing Zhou
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou, China
| | - Shouyang Yu
- Guizhou Key Laboratory of Brain Science, Zunyi Medical University, Guizhou, China
| | - Rulan Yi
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou, China
| | - Dan Luo
- Guizhou Key Laboratory of Anesthesia and Organ Protection, Zunyi Medical University, Guizhou, China
| | - Xiaoyun Fu
- Department of Critical Care Medicine, Affiliated Hospital of Zunyi Medical University, Guizhou, China
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12
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Lei T, Hu Z, Ding R, Chen J, Li S, Zhang F, Pu X, Zhao N. Exploring the Activation Mechanism of a Metabotropic Glutamate Receptor Homodimer via Molecular Dynamics Simulation. ACS Chem Neurosci 2020; 11:133-145. [PMID: 31815422 DOI: 10.1021/acschemneuro.9b00425] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Metabotropic glutamate receptors of class C GPCRs exist as constitutive dimers, which play important roles in activating excitatory synapses of the central nervous system. However, the activation mechanism induced by agonists has not been clarified in experiments. To address the problem, we used microsecond all-atom molecular dynamics (MD) simulation couple with protein structure network (PSN) to explore the glutamate-induced activation for the mGluR1 homodimer. The results indicate that glutamate binding stabilizes not only the closure of Venus flytrap domains but also the polar interaction of LB2-LB2, in turn keeping the extracelluar domain in the active state. The activation of the extracelluar domain drives transmembrane domains (TMDs) of the two protomers closer and induces asymmetric activation for the TMD domains of the two protomers. One protomer with lower binding affinity to the agonist is activated, while the other protomer with higher binding energy is still in the inactive state. The PSN analysis identifies the allosteric regulation pathway from the ligand-binding pocket in the extracellular domain to the G-protein binding site in the intracellular TMD region and further reveals that the asymmetric activation is attributed to a combination of trans-pathway and cis-pathway regulations from two glumatates, rather than a single activation pathway. These observations could provide valuable molecular information for understanding of the structure and the implications in drug efficacy for the class C GPCR dimers.
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Affiliation(s)
- Ting Lei
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Zhenxin Hu
- College of Computer Science, Sichuan University, Chengdu 610064, China
| | - Ruolin Ding
- West China School of Stomatology, Sichuan University, Chengdu 610041, China
| | - Jianfang Chen
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Shiqi Li
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Fuhui Zhang
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Xuemei Pu
- College of Chemistry, Sichuan University, Chengdu 610064, China
| | - Nanrong Zhao
- College of Chemistry, Sichuan University, Chengdu 610064, China
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13
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Unstructured loop is essential for the activation of mGluR2. Biochem Biophys Res Commun 2020; 521:775-778. [DOI: 10.1016/j.bbrc.2019.10.187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Accepted: 10/28/2019] [Indexed: 11/23/2022]
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14
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Dal Prà I, Armato U, Chiarini A. Family C G-Protein-Coupled Receptors in Alzheimer's Disease and Therapeutic Implications. Front Pharmacol 2019; 10:1282. [PMID: 31719824 PMCID: PMC6826475 DOI: 10.3389/fphar.2019.01282] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 10/07/2019] [Indexed: 12/12/2022] Open
Abstract
Alzheimer’s disease (AD), particularly its sporadic or late-onset form (SAD/LOAD), is the most prevalent (96–98% of cases) neurodegenerative dementia in aged people. AD’s neuropathology hallmarks are intrabrain accumulation of amyloid-β peptides (Aβs) and of hyperphosphorylated Tau (p-Tau) proteins, diffuse neuroinflammation, and progressive death of neurons and oligodendrocytes. Mounting evidences suggest that family C G-protein-coupled receptors (GPCRs), which include γ-aminobutyric acid B receptors (GABABRs), metabotropic glutamate receptors (mGluR1-8), and the calcium-sensing receptor (CaSR), are involved in many neurotransmitter systems that dysfunction in AD. This review updates the available knowledge about the roles of GPCRs, particularly but not exclusively those expressed by brain astrocytes, in SAD/LOAD onset and progression, taking stock of their respective mechanisms of action and of their potential as anti-AD therapeutic targets. In particular, GABABRs prevent Aβs synthesis and neuronal hyperexcitability and group I mGluRs play important pathogenetic roles in transgenic AD-model animals. Moreover, the specific binding of Aβs to the CaSRs of human cortical astrocytes and neurons cultured in vitro engenders a pathological signaling that crucially promotes the surplus synthesis and release of Aβs and hyperphosphorylated Tau proteins, and also of nitric oxide, vascular endothelial growth factor-A, and proinflammatory agents. Concurrently, Aβs•CaSR signaling hinders the release of soluble (s)APP-α peptide, a neurotrophic agent and GABABR1a agonist. Altogether these effects progressively kill human cortical neurons in vitro and likely also in vivo. Several CaSR’s negative allosteric modulators suppress all the noxious effects elicited by Aβs•CaSR signaling in human cortical astrocytes and neurons thus safeguarding neurons’ viability in vitro and raising hopes about their potential therapeutic benefits in AD patients. Further basic and clinical investigations on these hot topics are needed taking always heed that activation of the several brain family C GPCRs may elicit divergent upshots according to the models studied.
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Affiliation(s)
- Ilaria Dal Prà
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Ubaldo Armato
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
| | - Anna Chiarini
- Human Histology and Embryology Unit, University of Verona Medical School, Verona, Italy
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15
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Hajj M, De Vita T, Vol C, Renassia C, Bologna JC, Brabet I, Cazade M, Pastore M, Blahos J, Labesse G, Pin JP, Prézeau L. Nonclassical Ligand-Independent Regulation of Go Protein by an Orphan Class C G-Protein–Coupled Receptor. Mol Pharmacol 2019; 96:233-246. [DOI: 10.1124/mol.118.113019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 05/28/2019] [Indexed: 01/20/2023] Open
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16
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Huang Y, Lu D, Liu H, Liu S, Jiang S, Pang GC, Liu Y. Preliminary research on the receptor–ligand recognition mechanism of umami by an hT1R1 biosensor. Food Funct 2019; 10:1280-1287. [DOI: 10.1039/c8fo02522c] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The biosensor reflecting the linkage of the umami signal during conduction and amplification, and the study on the receptor–ligand recognition mechanism.
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Affiliation(s)
- Yulin Huang
- College of Food Science and Technology
- Shanghai Ocean University
- Shanghai 201306
- PR China
| | - Dingqiang Lu
- College of Biotechnology and Food Science
- Tianjin University of Commerce
- Tianjin 300134
- PR China
| | - Hai Liu
- College of Food Science and Technology
- Shanghai Ocean University
- Shanghai 201306
- PR China
| | - Suyao Liu
- College of Food Science and Technology
- Shanghai Ocean University
- Shanghai 201306
- PR China
| | - Shui Jiang
- Department of Food Science and Technology
- School of Agriculture and Biology
- Shanghai Jiao Tong University
- Shanghai 200240
- China
| | - Guang-chang Pang
- College of Biotechnology and Food Science
- Tianjin University of Commerce
- Tianjin 300134
- PR China
| | - Yuan Liu
- Department of Food Science and Technology
- School of Agriculture and Biology
- Shanghai Jiao Tong University
- Shanghai 200240
- China
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17
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Derouiche L, Massotte D. G protein-coupled receptor heteromers are key players in substance use disorder. Neurosci Biobehav Rev 2018; 106:73-90. [PMID: 30278192 DOI: 10.1016/j.neubiorev.2018.09.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 09/25/2018] [Accepted: 09/26/2018] [Indexed: 12/19/2022]
Abstract
G protein-coupled receptors (GPCR) represent the largest family of membrane proteins in the human genome. Physical association between two different GPCRs is linked to functional interactions which generates a novel entity, called heteromer, with specific ligand binding and signaling properties. Heteromerization is increasingly recognized to take place in the mesocorticolimbic pathway and to contribute to various aspects related to substance use disorder. This review focuses on heteromers identified in brain areas relevant to drug addiction. We report changes at the molecular and cellular levels that establish specific functional impact and highlight behavioral outcome in preclinical models. Finally, we briefly discuss selective targeting of native heteromers as an innovative therapeutic option.
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Affiliation(s)
- Lyes Derouiche
- Institut des Neurosciences Cellulaires et Integratives, UPR 3212, 5 rue Blaise Pascal, F-67000 Strasbourg, France
| | - Dominique Massotte
- Institut des Neurosciences Cellulaires et Integratives, UPR 3212, 5 rue Blaise Pascal, F-67000 Strasbourg, France.
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18
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Obri A, Khrimian L, Karsenty G, Oury F. Osteocalcin in the brain: from embryonic development to age-related decline in cognition. Nat Rev Endocrinol 2018; 14:174-182. [PMID: 29376523 PMCID: PMC5958904 DOI: 10.1038/nrendo.2017.181] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
A remarkable, unexpected aspect of the bone-derived hormone osteocalcin is that it is necessary for both brain development and brain function in the mouse, as its absence results in a profound deficit in spatial learning and memory and an exacerbation of anxiety-like behaviour. The regulation of cognitive function by osteocalcin, together with the fact that its circulating levels decrease in midlife compared with adolescence in all species tested, raised the prospect that osteocalcin might be an anti-geronic hormone that could prevent age-related cognitive decline. As presented in this Review, recent data indicate that this is indeed the case and that osteocalcin is necessary for the anti-geronic activity recently ascribed to the plasma of young wild-type mice. The diversity and amplitude of the functions of osteocalcin in the brain, during development and postnatally, had long called for the identification of its receptor in the brain, which was also recently achieved. This Review presents our current understanding of the biology of osteocalcin in the brain, highlighting the bony vertebrate specificity of the regulation of cognitive function and pointing toward where therapeutic opportunities might exist.
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Affiliation(s)
- Arnaud Obri
- Department of Genetics and Development, Columbia University Medical Center, 701 W 168th St. Rm 1602, New York City, New York 10032, USA
| | - Lori Khrimian
- Department of Genetics and Development, Columbia University Medical Center, 701 W 168th St. Rm 1602, New York City, New York 10032, USA
| | - Gerard Karsenty
- Department of Genetics and Development, Columbia University Medical Center, 701 W 168th St. Rm 1602, New York City, New York 10032, USA
| | - Franck Oury
- Institut Necker-Enfants Malades, CS 61431, Paris, France Institut National de la Santé et de la Recherche Médicale, U1151, F-75014 Paris, France Université Paris Descartes, Sorbonne Paris Cité, 75006 Paris, France
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19
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Scholler P, Nevoltris D, de Bundel D, Bossi S, Moreno-Delgado D, Rovira X, Møller TC, El Moustaine D, Mathieu M, Blanc E, McLean H, Dupuis E, Mathis G, Trinquet E, Daniel H, Valjent E, Baty D, Chames P, Rondard P, Pin JP. Allosteric nanobodies uncover a role of hippocampal mGlu2 receptor homodimers in contextual fear consolidation. Nat Commun 2017; 8:1967. [PMID: 29213077 PMCID: PMC5719040 DOI: 10.1038/s41467-017-01489-1] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 09/15/2017] [Indexed: 11/09/2022] Open
Abstract
Antibodies have enormous therapeutic and biotechnology potential. G protein-coupled receptors (GPCRs), the main targets in drug development, are of major interest in antibody development programs. Metabotropic glutamate receptors are dimeric GPCRs that can control synaptic activity in a multitude of ways. Here we identify llama nanobodies that specifically recognize mGlu2 receptors, among the eight subtypes of mGluR subunits. Among these nanobodies, DN10 and 13 are positive allosteric modulators (PAM) on homodimeric mGlu2, while DN10 displays also a significant partial agonist activity. DN10 and DN13 have no effect on mGlu2-3 and mGlu2-4 heterodimers. These PAMs enhance the inhibitory action of the orthosteric mGlu2/mGlu3 agonist, DCG-IV, at mossy fiber terminals in the CA3 region of hippocampal slices. DN13 also impairs contextual fear memory when injected in the CA3 region of hippocampal region. These data highlight the potential of developing antibodies with allosteric actions on GPCRs to better define their roles in vivo.
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Affiliation(s)
- Pauline Scholler
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
- Cisbio Bioassays, F-30200, Codolet, France
| | - Damien Nevoltris
- Cisbio Bioassays, F-30200, Codolet, France
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, F-13009, Marseille, France
| | - Dimitri de Bundel
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Simon Bossi
- CNRS UMR9197, Université Paris-Sud, Institut des Neurosciences Paris-Saclay, F-91405, Orsay, France
| | - David Moreno-Delgado
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Thor C Møller
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Driss El Moustaine
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Michaël Mathieu
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Emilie Blanc
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Heather McLean
- CNRS UMR9197, Université Paris-Sud, Institut des Neurosciences Paris-Saclay, F-91405, Orsay, France
| | | | | | | | - Hervé Daniel
- CNRS UMR9197, Université Paris-Sud, Institut des Neurosciences Paris-Saclay, F-91405, Orsay, France
| | - Emmanuel Valjent
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France
| | - Daniel Baty
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, F-13009, Marseille, France
| | - Patrick Chames
- Aix Marseille Univ, CNRS, INSERM, Institut Paoli-Calmettes, CRCM, F-13009, Marseille, France.
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France.
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle, CNRS, INSERM, Univ. Montpellier, F-34094, Montpellier, France.
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20
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Yiannakas A, Rosenblum K. The Insula and Taste Learning. Front Mol Neurosci 2017; 10:335. [PMID: 29163022 PMCID: PMC5676397 DOI: 10.3389/fnmol.2017.00335] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2017] [Accepted: 10/03/2017] [Indexed: 12/29/2022] Open
Abstract
The sense of taste is a key component of the sensory machinery, enabling the evaluation of both the safety as well as forming associations regarding the nutritional value of ingestible substances. Indicative of the salience of the modality, taste conditioning can be achieved in rodents upon a single pairing of a tastant with a chemical stimulus inducing malaise. This robust associative learning paradigm has been heavily linked with activity within the insular cortex (IC), among other regions, such as the amygdala and medial prefrontal cortex. A number of studies have demonstrated taste memory formation to be dependent on protein synthesis at the IC and to correlate with the induction of signaling cascades involved in synaptic plasticity. Taste learning has been shown to require the differential involvement of dopaminergic GABAergic, glutamatergic, muscarinic neurotransmission across an extended taste learning circuit. The subsequent activation of downstream protein kinases (ERK, CaMKII), transcription factors (CREB, Elk-1) and immediate early genes (c-fos, Arc), has been implicated in the regulation of the different phases of taste learning. This review discusses the relevant neurotransmission, molecular signaling pathways and genetic markers involved in novel and aversive taste learning, with a particular focus on the IC. Imaging and other studies in humans have implicated the IC in the pathophysiology of a number of cognitive disorders. We conclude that the IC participates in circuit-wide computations that modulate the interception and encoding of sensory information, as well as the formation of subjective internal representations that control the expression of motivated behaviors.
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Affiliation(s)
- Adonis Yiannakas
- Sagol Department of Neuroscience, University of Haifa, Haifa, Israel
| | - Kobi Rosenblum
- Sagol Department of Neuroscience, University of Haifa, Haifa, Israel
- Center for Gene Manipulation in the Brain, University of Haifa, Haifa, Israel
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21
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Lecat-Guillet N, Monnier C, Rovira X, Kniazeff J, Lamarque L, Zwier JM, Trinquet E, Pin JP, Rondard P. FRET-Based Sensors Unravel Activation and Allosteric Modulation of the GABA B Receptor. Cell Chem Biol 2017; 24:360-370. [PMID: 28286129 DOI: 10.1016/j.chembiol.2017.02.011] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 11/21/2016] [Accepted: 02/10/2017] [Indexed: 01/11/2023]
Abstract
The main inhibitory neurotransmitter, γ-aminobutyric acid (GABA), modulates many synapses by activating the G protein-coupled receptor GABAB, which is a target for various therapeutic applications. It is an obligatory heterodimer made of GB1 and GB2 that can be regulated by positive allosteric modulators (PAMs). The molecular mechanism of activation of the GABAB receptor remains poorly understood. Here, we have developed FRET-based conformational GABAB sensors compatible with high-throughput screening. We identified conformational changes occurring within the extracellular and transmembrane domains upon receptor activation, which are smaller than those observed in the related metabotropic glutamate receptors. These sensors also allow discrimination between agonists of different efficacies and between PAMs that have different modes of action, which has not always been possible using conventional functional assays. Our study brings important new information on the activation mechanism of the GABAB receptor and should facilitate the screening and identification of new chemicals targeting this receptor.
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Affiliation(s)
- Nathalie Lecat-Guillet
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Carine Monnier
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Xavier Rovira
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Julie Kniazeff
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | | | | | | | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), CNRS, INSERM, University of Montpellier, 141 rue de la Cardonille, 34094 Montpellier, France.
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22
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Gaitonde SA, González-Maeso J. Contribution of heteromerization to G protein-coupled receptor function. Curr Opin Pharmacol 2016; 32:23-31. [PMID: 27835800 DOI: 10.1016/j.coph.2016.10.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 10/22/2016] [Accepted: 10/24/2016] [Indexed: 12/22/2022]
Abstract
G protein-coupled receptors (GPCRs) are a remarkably multifaceted family of transmembrane proteins that exert a variety of physiological effects. Although family A GPCRs are able to operate as monomers, there is increasing evidence that heteromerization represents a fundamental aspect of receptor function, trafficking and pharmacology. Most recently, it has been suggested that GPCR heteromers may play a crucial role as new molecular targets of heteromer-selective and bivalent ligands. The current review summarizes key recent developments in these topics.
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Affiliation(s)
- Supriya A Gaitonde
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States
| | - Javier González-Maeso
- Department of Physiology and Biophysics, Virginia Commonwealth University School of Medicine, Richmond, VA 23298, United States.
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23
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Kiyonaka S, Kubota R, Michibata Y, Sakakura M, Takahashi H, Numata T, Inoue R, Yuzaki M, Hamachi I. Allosteric activation of membrane-bound glutamate receptors using coordination chemistry within living cells. Nat Chem 2016; 8:958-67. [DOI: 10.1038/nchem.2554] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 05/20/2016] [Indexed: 12/30/2022]
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24
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Bruno V, Caraci F, Copani A, Matrisciano F, Nicoletti F, Battaglia G. The impact of metabotropic glutamate receptors into active neurodegenerative processes: A "dark side" in the development of new symptomatic treatments for neurologic and psychiatric disorders. Neuropharmacology 2016; 115:180-192. [PMID: 27140693 DOI: 10.1016/j.neuropharm.2016.04.044] [Citation(s) in RCA: 52] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Revised: 04/22/2016] [Accepted: 04/28/2016] [Indexed: 12/17/2022]
Abstract
Metabotropic glutamate (mGlu) receptor ligands are under clinical development for the treatment of CNS disorders with high social and economic burden, such as schizophrenia, major depressive disorder (MDD), and Parkinson's disease (PD), and are promising drug candidates for the treatment of Alzheimer's disease (AD). So far, clinical studies have shown symptomatic effects of mGlu receptor ligands, but it is unknown whether these drugs act as disease modifiers or, at the opposite end, they accelerate disease progression by enhancing neurodegeneration. This is a fundamental issue in the treatment of PD and AD, and is also an emerging theme in the treatment of schizophrenia and MDD, in which neurodegeneration is also present and contribute to disease progression. Moving from in vitro data and preclinical studies, we discuss the potential impact of drugs targeting mGlu2, mGlu3, mGlu4 and mGlu5 receptor ligands on active neurodegeneration associated with AD, PD, schizophrenia, and MDD. We wish to highlight that our final comments on the best drug candidates are not influenced by commercial interests or by previous or ongoing collaborations with drug companies. This article is part of the Special Issue entitled 'Metabotropic Glutamate Receptors, 5 years on'.
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Affiliation(s)
- Valeria Bruno
- Department of Physiology and Pharmacology, University Sapienza, 00185 Rome, Italy; I.R.C.C.S. Neuromed, 86077 Pozzilli, Italy.
| | - Filippo Caraci
- Department of Drug Sciences, University of Catania, 95125 Catania, Italy; I.R.C.C.S. Associazione Oasi Maria S.S., Institute for Research on Mental Retardation and Brain Aging, 94018 Troina, Italy
| | - Agata Copani
- Department of Drug Sciences, University of Catania, 95125 Catania, Italy; National Research Council, Institute of Biostructure and Bioimaging (IBB-CNR), 95126 Catania, Italy
| | - Francesco Matrisciano
- Department of Psychiatry and Behavioral Sciences, Northwestern Feinberg School of Medicine, Chicago, USA
| | - Ferdinando Nicoletti
- Department of Physiology and Pharmacology, University Sapienza, 00185 Rome, Italy; I.R.C.C.S. Neuromed, 86077 Pozzilli, Italy
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25
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Jang JW, Cho NC, Min SJ, Cho YS, Park KD, Seo SH, No KT, Pae AN. Novel Scaffold Identification of mGlu1 Receptor Negative Allosteric Modulators Using a Hierarchical Virtual Screening Approach. Chem Biol Drug Des 2015; 87:239-56. [DOI: 10.1111/cbdd.12654] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/15/2015] [Accepted: 08/18/2015] [Indexed: 11/28/2022]
Affiliation(s)
- Jae Wan Jang
- Center for Neuro-Medicine; Brain Science Institute; Korea Institute of Science and Technology (KIST); Hwarangno 14-gil 5 Seongbuk-gu, Seoul 136-791 Korea
- Department of Biological Chemistry; School of Science; Korea University of Science and Technology; 52 Eoeun dong Yuseong-gu, Daejeon 305-333 Korea
| | - Nam-Chul Cho
- Center for Neuro-Medicine; Brain Science Institute; Korea Institute of Science and Technology (KIST); Hwarangno 14-gil 5 Seongbuk-gu, Seoul 136-791 Korea
- Department of Biotechnology; Yonsei University; Seodaemun-gu, Seoul 120-749 Korea
| | - Sun-Joon Min
- Department of Applied Chemistry; Hanyang University; Ansan, Gyeonggi-do 15588 Korea
| | - Yong Seo Cho
- Center for Neuro-Medicine; Brain Science Institute; Korea Institute of Science and Technology (KIST); Hwarangno 14-gil 5 Seongbuk-gu, Seoul 136-791 Korea
- Department of Biological Chemistry; School of Science; Korea University of Science and Technology; 52 Eoeun dong Yuseong-gu, Daejeon 305-333 Korea
| | - Ki Duk Park
- Center for Neuro-Medicine; Brain Science Institute; Korea Institute of Science and Technology (KIST); Hwarangno 14-gil 5 Seongbuk-gu, Seoul 136-791 Korea
- Department of Biological Chemistry; School of Science; Korea University of Science and Technology; 52 Eoeun dong Yuseong-gu, Daejeon 305-333 Korea
| | - Seon Hee Seo
- Center for Neuro-Medicine; Brain Science Institute; Korea Institute of Science and Technology (KIST); Hwarangno 14-gil 5 Seongbuk-gu, Seoul 136-791 Korea
| | - Kyoung Tai No
- Department of Biotechnology; Yonsei University; Seodaemun-gu, Seoul 120-749 Korea
| | - Ae Nim Pae
- Center for Neuro-Medicine; Brain Science Institute; Korea Institute of Science and Technology (KIST); Hwarangno 14-gil 5 Seongbuk-gu, Seoul 136-791 Korea
- Department of Biological Chemistry; School of Science; Korea University of Science and Technology; 52 Eoeun dong Yuseong-gu, Daejeon 305-333 Korea
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26
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Role of post-translational modifications on structure, function and pharmacology of class C G protein-coupled receptors. Eur J Pharmacol 2015; 763:233-40. [PMID: 25981296 DOI: 10.1016/j.ejphar.2015.05.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 03/06/2015] [Accepted: 05/11/2015] [Indexed: 11/22/2022]
Abstract
G protein-coupled receptors are divided into three classes (A, B and C) based on homology of their seven transmembrane domains. Class C is the smallest class with 22 human receptor subtypes including eight metabotropic glutamate (mGlu1-8) receptors, two GABAB receptors (GABAB1 and GABAB2), three taste receptors (T1R1-3), one calcium-sensing (CaS) receptor, one GPCR, class C, group 6, subtype A (GPRC6) receptor, and seven orphan receptors. G protein-coupled receptors undergo a number of post-translational modifications, which regulate their structure, function and/or pharmacology. Here, we review the existence of post-translational modifications in class C G protein-coupled receptors and their regulatory roles, with particular focus on glycosylation, phosphorylation, ubiquitination, SUMOylation, disulphide bonding and lipidation.
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27
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Xue L, Rovira X, Scholler P, Zhao H, Liu J, Pin JP, Rondard P. Major ligand-induced rearrangement of the heptahelical domain interface in a GPCR dimer. Nat Chem Biol 2015; 11:134-40. [PMID: 25503927 DOI: 10.1038/nchembio.1711] [Citation(s) in RCA: 151] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 10/14/2014] [Indexed: 12/30/2022]
Abstract
G protein-coupled receptors (GPCRs) are major players in cell communication. Although they form functional monomers, increasing evidence indicates that GPCR dimerization has a critical role in cooperative phenomena that are important for cell signal integration. However, the structural bases of these phenomena remain elusive. Here, using well-characterized receptor dimers, the metabotropic glutamate receptors (mGluRs), we show that structural changes at the dimer interface are linked to receptor activation. We demonstrate that the main dimer interface is formed by transmembrane α helix 4 (TM4) and TM5 in the inactive state and by TM6 in the active state. This major change in the dimer interface is required for receptor activity because locking the TM4-TM5 interface prevents activation by agonist, whereas locking the TM6 interface leads to a constitutively active receptor. These data provide important information on the activation mechanism of mGluRs and improve our understanding of the structural basis of the negative cooperativity observed in these GPCR dimers.
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MESH Headings
- Alanine/genetics
- Animals
- COS Cells
- Chlorocebus aethiops
- Cysteine/genetics
- HEK293 Cells
- Humans
- Ligands
- Models, Molecular
- Mutagenesis, Site-Directed
- Protein Binding
- Protein Multimerization
- Protein Structure, Tertiary
- Protein Subunits
- Rats
- Receptor, Metabotropic Glutamate 5/agonists
- Receptor, Metabotropic Glutamate 5/chemistry
- Receptor, Metabotropic Glutamate 5/genetics
- Receptors, GABA-B/chemistry
- Receptors, GABA-B/genetics
- Receptors, GABA-B/metabolism
- Receptors, Metabotropic Glutamate/agonists
- Receptors, Metabotropic Glutamate/chemistry
- Receptors, Metabotropic Glutamate/genetics
- Transcriptional Activation
- Transfection
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Affiliation(s)
- Li Xue
- 1] Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China. [2] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [3] INSERM, U661, Montpellier, France. [4] Université Montpellier 1 &2, Montpellier, France
| | - Xavier Rovira
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Pauline Scholler
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Han Zhao
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jianfeng Liu
- Cellular Signaling Laboratory, Key Laboratory of Molecular Biophysics of Ministry of Education, School of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Jean-Philippe Pin
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
| | - Philippe Rondard
- 1] CNRS, UMR5203, Institut de Génomique Fonctionnelle, Montpellier, France. [2] INSERM, U661, Montpellier, France. [3] Université Montpellier 1 &2, Montpellier, France
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28
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Rondard P, Pin JP. Dynamics and modulation of metabotropic glutamate receptors. Curr Opin Pharmacol 2015; 20:95-101. [DOI: 10.1016/j.coph.2014.12.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/29/2014] [Accepted: 12/01/2014] [Indexed: 11/28/2022]
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29
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Absalom N, Yamamoto I, O'Hagan D, Hunter L, Chebib M. Probing the Mode of Neurotransmitter Binding to GABA Receptors Using Selectively Fluorinated GABA Analogues. Aust J Chem 2015. [DOI: 10.1071/ch14456] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Stereoselective fluorination is a useful technique for controlling the conformations of organic molecules. This concept has been exploited to create conformationally biased analogues of the neurotransmitter gamma-aminobutyric acid (GABA). Mono- and di-fluorinated GABA analogues are found to adopt different conformations, due to subtle stereoelectronic effects associated with the C–F bond. These conformationally biased GABA analogues exhibit different shape-dependent selectivity patterns towards GABAA, GABAB, and GABAC receptors, providing valuable information on the binding modes of the natural ligand at these medicinally important targets.
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30
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Laletin V, Bykov Y. General anesthetics as a factor of effective neuroprotection in ischemic stroke models. ACTA ACUST UNITED AC 2015; 61:440-8. [DOI: 10.18097/pbmc20156104440] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Stroke is the second leading cause of death in the world. Unfortunately, only a few drugs have been proved in clinical trials. Drug development of the last decade has been focused substantially on a promising and heterogeneous group of neuroprotective drugs. Hundreds of compounds were suggested as new putative neuroprotectors, which effectiveness was confirmed in preclinical trials only. At the present time discrepancy between results of preclinical studies and clinical trials requires careful analysis. One of the least evaluated and probably the most noticeable reasons is general anesthesia - an obligatory component of an overwhelming majority of existing animal stroke models. The aim of the review is to describe known mechanisms of common general anesthetics influence on ionotropic and metabotropic plasma membrane receptors, and key signal pathways involved in neuronal hypoxic-ischemic injury and survival
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Affiliation(s)
- V.S. Laletin
- Irkutsk State Medical University, Irkutsk, Russia
| | - Y.N. Bykov
- Irkutsk State Medical University, Irkutsk, Russia
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31
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Metabotropic glutamate receptors as drug targets: what's new? Curr Opin Pharmacol 2014; 20:89-94. [PMID: 25506748 DOI: 10.1016/j.coph.2014.12.002] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 11/23/2022]
Abstract
The question in the title: 'what's new?' has two facets. First, are 'clinical' expectations met with success? Second, is the number of CNS disorders targeted by mGlu drugs still increasing? The answer to the first question is 'no', because development program with promising drugs in the treatment of schizophrenia, Parkinson's disease, and Fragile X syndrome have been discontinued. Nonetheless, we continue to be optimistic because there is still the concrete hope that some of these drugs are beneficial in targeted subpopulations of patients. The answer to the second question is 'yes', because mGlu ligands are promising targets for 'new' disorders such as type-1 spinocerebellar ataxia and absence epilepsy. In addition, the increasing availability of pharmacological tools may push mGlu7 and mGlu8 receptors into the clinical scenario. After almost 30 years from their discovery, mGlu receptors are still alive.
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32
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Clemmensen C, Smajilovic S, Wellendorph P, Bräuner-Osborne H. The GPCR, class C, group 6, subtype A (GPRC6A) receptor: from cloning to physiological function. Br J Pharmacol 2014; 171:1129-41. [PMID: 24032653 DOI: 10.1111/bph.12365] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 07/25/2013] [Accepted: 08/26/2013] [Indexed: 12/16/2022] Open
Abstract
GPRC6A (GPCR, class C, group 6, subtype A) is a class C GPCR that has been cloned from human, mouse and rat. Several groups have shown that the receptor is activated by a range of basic and small aliphatic L-α-amino acids of which L-arginine, L-lysine and L-ornithine are the most potent compounds with EC50 values in the mid-micromolar range. In addition, several groups have shown that the receptor is either directly activated or positively modulated by divalent cations such as Ca(2+) albeit in concentrations above 5 mM, which is above the physiological concentration in most tissues. More recently, the peptide osteocalcin and the steroid testosterone have also been suggested to be endogenous GPRC6A agonists. The receptor is widely expressed in all three species which, along with the omnipresence of the amino acids and divalent cation ligands, suggest that the receptor could be involved in a broad range of physiological functions. So far, this has mainly been addressed by analyses of genetically modified mice where the GPRC6A receptor has been ablated. Although there has been some discrepancies among results reported from different groups, there is increasing evidence that the receptor is involved in regulation of inflammation, metabolism and endocrine functions. GPRC6A could thus be an interesting target for new drugs in these therapeutic areas.
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Affiliation(s)
- C Clemmensen
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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33
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Fine tuning of sub-millisecond conformational dynamics controls metabotropic glutamate receptors agonist efficacy. Nat Commun 2014; 5:5206. [DOI: 10.1038/ncomms6206] [Citation(s) in RCA: 76] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 09/09/2014] [Indexed: 11/08/2022] Open
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34
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Haas LT, Kostylev MA, Strittmatter SM. Therapeutic molecules and endogenous ligands regulate the interaction between brain cellular prion protein (PrPC) and metabotropic glutamate receptor 5 (mGluR5). J Biol Chem 2014; 289:28460-77. [PMID: 25148681 DOI: 10.1074/jbc.m114.584342] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Soluble Amyloid-β oligomers (Aβo) can trigger Alzheimer disease (AD) pathophysiology by binding to cell surface cellular prion protein (PrP(C)). PrP(C) interacts physically with metabotropic glutamate receptor 5 (mGluR5), and this interaction controls the transmission of neurotoxic signals to intracellular substrates. Because the interruption of the signal transduction from PrP(C) to mGluR5 has therapeutic potential for AD, we developed assays to explore the effect of endogenous ligands, agonists/antagonists, and antibodies on the interaction between PrP(C) and mGluR5 in cell lines and mouse brain. We show that the PrP(C) segment of amino acids 91-153 mediates the interaction with mGluR5. Agonists of mGluR5 increase the mGluR5-PrP(C) interaction, whereas mGluR5 antagonists suppress protein association. Synthetic Aβo promotes the protein interaction in mouse brain and transfected HEK-293 cell membrane preparations. The interaction of PrP(C) and mGluR5 is enhanced dramatically in the brains of familial AD transgenic model mice. In brain homogenates with Aβo, the interaction of PrP(C) and mGluR5 is reversed by mGluR5-directed antagonists or antibodies directed against the PrP(C) segment of amino acids 91-153. Silent allosteric modulators of mGluR5 do not alter Glu or basal mGluR5 activity, but they disrupt the Aβo-induced interaction of mGluR5 with PrP(C). The assays described here have the potential to identify and develop new compounds that inhibit the interaction of PrP(C) and mGluR5, which plays a pivotal role in the pathogenesis of Alzheimer disease by transmitting the signal from extracellular Aβo into the cytosol.
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Affiliation(s)
- Laura T Haas
- From the Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06536 and the Graduate School of Cellular and Molecular Neuroscience, University of Tübingen, D-72074 Tübingen, Germany
| | - Mikhail A Kostylev
- From the Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06536 and
| | - Stephen M Strittmatter
- From the Cellular Neuroscience, Neurodegeneration and Repair Program, Department of Neurology, Yale University School of Medicine, New Haven, Connecticut 06536 and
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35
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Zakrys L, Ward RJ, Pediani JD, Godin AG, Graham GJ, Milligan G. Roundabout 1 exists predominantly as a basal dimeric complex and this is unaffected by binding of the ligand Slit2. Biochem J 2014; 461:61-73. [PMID: 24673457 DOI: 10.1042/bj20140190] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Robo (Roundabout) receptors and their Slit polypeptide ligands are known to play key roles in neuronal development and have been implicated in both angiogenesis and cancer. Like the other family members, Robo1 is a large single transmembrane domain polypeptide containing a series of well-defined extracellular elements. However, the intracellular domain lacks structural definition and little is known about the quaternary structure of Robo receptors or how binding of a Slit might affect this. To address these questions combinations of both autofluorescent protein-based FRET imaging and time-resolved FRET were employed. Both approaches identified oligomeric organization of Robo1 that did not require the presence of the intracellular domain. SpIDA (spatial intensity distribution analysis) of eGFP-tagged forms of Robo1 indicated that for a C-terminally deleted version approximately two-thirds of the receptor was present as a dimer and one-third as a monomer. By contrast, full-length Robo1 was present almost exclusively as a dimer. In each case this was unaffected by the addition of Slit2, although parallel studies demonstrated the biological activity of Slit2 and its interaction with Robo1. Deletion of both the immunoglobulin and fibronectin type III extracellular repeats prevented dimer formation, with the immunoglobulin repeats providing the bulk of the protein-protein interaction affinity.
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Affiliation(s)
| | - Richard J Ward
- *Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
| | - John D Pediani
- *Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
| | - Antoine G Godin
- ‡Laboratoire Photonique, Numérique et Nanosciences (LP2N) Institut d'Optique Graduate School, CNRS and Université Bordeaux, 351 cours de la libération, 33405 Talence Cedex, France
| | - Gerard J Graham
- †Institute of Infection, Immunity and Inflammation, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
| | - Graeme Milligan
- *Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, U.K
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36
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Massotte D. In vivo opioid receptor heteromerization: where do we stand? Br J Pharmacol 2014; 172:420-34. [PMID: 24666391 DOI: 10.1111/bph.12702] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 03/17/2014] [Accepted: 03/19/2014] [Indexed: 12/22/2022] Open
Abstract
UNLABELLED Opioid receptors are highly homologous GPCRs that modulate brain function at all levels of neural integration, including autonomous, sensory, emotional and cognitive processing. Opioid receptors functionally interact in vivo, but the underlying mechanisms involving direct receptor-receptor interactions, affecting signalling pathways or engaging different neuronal circuits, remain unsolved. Heteromer formation through direct physical interaction between two opioid receptors or between an opioid receptor and a non-opioid one has been postulated and can be characterized by specific ligand binding, receptor signalling and trafficking properties. However, despite numerous studies in heterologous systems, evidence for physical proximity in vivo is only available for a limited number of opioid heteromers, and their physiopathological implication remains largely unknown mostly due to the lack of appropriate tools. Nonetheless, data collected so far using endogenous receptors point to a crucial role for opioid heteromers as a molecular entity that could underlie human pathologies such as alcoholism, acute or chronic pain as well as psychiatric disorders. Opioid heteromers therefore stand as new therapeutic targets for the drug discovery field. LINKED ARTICLES This article is part of a themed section on Opioids: New Pathways to Functional Selectivity. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-2.
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Affiliation(s)
- D Massotte
- Institut des Neurosciences Cellulaires et Intégratives, INCI, Strasbourg, France
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37
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Mølck C, Harpsøe K, Gloriam DE, Mathiesen JM, Nielsen SM, Bräuner-Osborne H. mGluR5: Exploration of Orthosteric and Allosteric Ligand Binding Pockets and Their Applications to Drug Discovery. Neurochem Res 2014; 39:1862-75. [DOI: 10.1007/s11064-014-1248-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 01/14/2014] [Accepted: 01/21/2014] [Indexed: 10/25/2022]
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38
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Ghanemi A. Targeting G protein coupled receptor-related pathways as emerging molecular therapies. Saudi Pharm J 2013; 23:115-29. [PMID: 25972730 PMCID: PMC4420995 DOI: 10.1016/j.jsps.2013.07.007] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Accepted: 07/29/2013] [Indexed: 12/20/2022] Open
Abstract
G protein coupled receptors (GPCRs) represent the most important targets in modern pharmacology because of the different functions they mediate, especially within brain and peripheral nervous system, and also because of their functional and stereochemical properties. In this paper, we illustrate, via a variety of examples, novel advances about the GPCR-related molecules that have been shown to play diverse roles in GPCR pathways and in pathophysiological phenomena. We have exemplified how those GPCRs’ pathways are, or might constitute, potential targets for different drugs either to stimulate, modify, regulate or inhibit the cellular mechanisms that are hypothesized to govern some pathologic, physiologic, biologic and cellular or molecular aspects both in vivo and in vitro. Therefore, influencing such pathways will, undoubtedly, lead to different therapeutical applications based on the related pharmacological implications. Furthermore, such new properties can be applied in different fields. In addition to offering fruitful directions for future researches, we hope the reviewed data, together with the elements found within the cited references, will inspire clinicians and researchers devoted to the studies on GPCR’s properties.
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Affiliation(s)
- Abdelaziz Ghanemi
- Department of Pharmacology, China Pharmaceutical University, Nanjing 210009, China
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39
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Koole C, Savage EE, Christopoulos A, Miller LJ, Sexton PM, Wootten D. Minireview: Signal bias, allosterism, and polymorphic variation at the GLP-1R: implications for drug discovery. Mol Endocrinol 2013; 27:1234-44. [PMID: 23864649 DOI: 10.1210/me.2013-1116] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
The glucagon-like peptide-1 receptor (GLP-1R) controls the physiological responses to the incretin hormone glucagon-like peptide-1 and is a major therapeutic target for the treatment of type 2 diabetes, owing to the broad range of effects that are mediated upon its activation. These include the promotion of glucose-dependent insulin secretion, increased insulin biosynthesis, preservation of β-cell mass, improved peripheral insulin action, and promotion of weight loss. Regulation of GLP-1R function is complex, with multiple endogenous and exogenous peptides that interact with the receptor that result in the activation of numerous downstream signaling cascades. The current understanding of GLP-1R signaling and regulation is limited, with the desired spectrum of signaling required for the ideal therapeutic outcome still to be determined. In addition, there are several single-nucleotide polymorphisms (used in this review as defining a natural change of single nucleotide in the receptor sequence; clinically, this is viewed as a single-nucleotide polymorphism only if the frequency of the mutation occurs in 1% or more of the population) distributed within the coding sequence of the receptor protein that have the potential to produce differential responses for distinct ligands. In this review, we discuss the current understanding of GLP-1R function, in particular highlighting recent advances in the field on ligand-directed signal bias, allosteric modulation, and probe dependence and the implications of these behaviors for drug discovery and development.
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Affiliation(s)
- Cassandra Koole
- Department of Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville 3052, Victoria, Australia
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40
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Sensing conformational changes in metabotropic glutamate receptors. Proc Natl Acad Sci U S A 2013; 110:5742-3. [PMID: 23542381 DOI: 10.1073/pnas.1303736110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
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41
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Cárdenas MI, Vellido A, Olier I, Rovira X, Giraldo J. Kernel Generative Topographic Mapping of Protein Sequences. Bioinformatics 2013. [DOI: 10.4018/978-1-4666-3604-0.ch044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The world of pharmacology is becoming increasingly dependent on the advances in the fields of genomics and proteomics. The –omics sciences bring about the challenge of how to deal with the large amounts of complex data they generate from an intelligent data analysis perspective. In this chapter, the authors focus on the analysis of a specific type of proteins, the G protein-coupled receptors, which are the target for over 15% of current drugs. They describe a kernel method of the manifold learning family for the analysis of protein amino acid symbolic sequences. This method sheds light on the structure of protein subfamilies, while providing an intuitive visualization of such structure.
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42
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Persistent receptor activity underlies group I mGluR-mediated cellular plasticity in CA3 neuron. J Neurosci 2013; 33:2526-40. [PMID: 23392681 DOI: 10.1523/jneurosci.3338-12.2013] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Plastic changes in cortical activities induced by group I metabotropic glutamate receptor (mGluR) stimulation include epileptogenesis, expressed in vitro as the conversion of normal neuronal activity to persistent, prolonged synchronized (ictal) discharges. At present, the mechanism that maintains group I mGluR-induced plasticity is not known. We examined this issue using hippocampal slices from guinea pigs and mice. Agonist [(S)-3,5-dihydroxyphenylglycine (DHPG), 30-50 μm)] stimulation of group I mGluRs induces persistent prolonged synchronized (ictal-like) discharges in CA3 that are associated with three identified excitatory cellular responses-suppression of spike afterhyperpolarizations, activation of a voltage-dependent cationic current, and increase in neuronal input resistance. Persistent prolonged synchronized discharges and the underlying excitatory cellular responses maintained following induction were reversibly blocked by mGluR1 antagonists [(S)-+-α-amino-4-carboxy-2-methylbenzeneacetic acid (LY 367385), 50, 100 μm; CPCCOEt (hydroxyimino)cyclopropa[b]chromen-1a-carboxylate ethyl ester, 100 μm], and to a lesser extent by the mGluR5 antagonist MPEP [2-methyl-6-(phenylethynyl)pyridine hydrochloride, 50 μm]. Activation of persistent cellular responses to DHPG were unaffected by tetrodotoxin (0.5-1 μm) or perfusion with low Ca(2+)(0.2 mm)-Mn(2+)(0.5 mm) media-conditions that suppress endogenous glutamate release. The pharmacological profile of the blocking action of the group I mGluR antagonist MCPG [(RS)-α-methyl-4-carboxyphenylglycine, 50-500 μm] on persistent cellular responses was different from that on cellular responses directly activated by DHPG. These data indicate that transient stimulation of group I mGluRs alters receptor properties, rendering them persistently active in the absence of applied agonist or endogenous glutamate activation. Persistent receptor activities, primarily involving mGluR1, maintain excitatory cellular responses and emergent prolonged synchronized discharges.
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43
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Illuminating the activation mechanisms and allosteric properties of metabotropic glutamate receptors. Proc Natl Acad Sci U S A 2013; 110:E1416-25. [PMID: 23487753 DOI: 10.1073/pnas.1215615110] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In multimeric cell-surface receptors, the conformational changes of the extracellular ligand-binding domains (ECDs) associated with receptor activation remain largely unknown. This is the case for the dimeric metabotropic glutamate receptors even though a number of ECD structures have been solved. Here, using an innovative approach based on cell-surface labeling and FRET, we demonstrate that a reorientation of the ECDs is associated with receptor and G-protein activation. Our approach helps identify partial agonists and highlights allosteric interactions between the effector and binding domains. Any approach expected to stabilize the active conformation of the effector domain increased the agonist potency in stabilizing the active ECDs conformation. These data provide key information on the structural dynamics and drug action at metabotropic glutamate receptors and validate an approach for tackling such analysis on other receptors.
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44
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Zhu S, Stroebel D, Yao CA, Taly A, Paoletti P. Allosteric signaling and dynamics of the clamshell-like NMDA receptor GluN1 N-terminal domain. Nat Struct Mol Biol 2013; 20:477-85. [PMID: 23454977 DOI: 10.1038/nsmb.2522] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 01/09/2013] [Indexed: 01/14/2023]
Abstract
N-methyl-D-aspartate receptors (NMDARs), neuronal glutamate-gated ion channels, are obligatory heterotetramers composed of GluN1 and GluN2 subunits. Each subunit contains two extracellular clamshell-like domains with an agonist-binding domain and a distal N-terminal domain (NTD). The GluN2 NTDs form mobile regulatory domains. In contrast, the dynamics of GluN1 NTD and its contribution to NMDAR function remain poorly understood. Here we show that GluN1 NTD is neither static nor functionally silent. Perturbing the conformation of GluN1 NTD affects both receptor gating and pharmacological properties. GluN1 NTD undergoes structural rearrangements that involve hinge bending and large twisting and untwisting motions, allowing for new intra- and intersubunit contacts. GluN1 NTD acts in trans with GluN2 NTD to influence binding of glutamate but, notably, not of GluN1 coagonist glycine. Our work uncovers a dynamic role of GluN1 NTD in controlling NMDAR function through new interdomain allosteric interactions.
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Affiliation(s)
- Shujia Zhu
- Ecole Normale Supérieure, Institut de Biologie, Paris, France
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45
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Distinct roles of metabotropic glutamate receptor dimerization in agonist activation and G-protein coupling. Proc Natl Acad Sci U S A 2012; 109:16342-7. [PMID: 22988116 DOI: 10.1073/pnas.1205838109] [Citation(s) in RCA: 135] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The eight metabotropic glutamate receptors (mGluRs) are key modulators of synaptic transmission and are considered promising targets for the treatment of various brain disorders. Whereas glutamate acts at a large extracellular domain, allosteric modulators have been identified that bind to the seven transmembrane domain (7TM) of these dimeric G-protein-coupled receptors (GPCRs). We show here that the dimeric organization of mGluRs is required for the modulation of active and inactive states of the 7TM by agonists, but is not necessary for G-protein activation. Monomeric mGlu2, either as an isolated 7TM or in full-length, purified and reconstituted into nanodiscs, couples to G proteins upon direct activation by a positive allosteric modulator. However, only a reconstituted full-length dimeric mGlu2 activates G protein upon glutamate binding, suggesting that dimerization is required for glutamate induced activation. These data show that, even for such well characterized GPCR dimers like mGluR2, a single 7TM is sufficient for G-protein coupling. Despite this observation, the necessity of dimeric architecture for signaling induced by the endogenous ligand glutamate confirms that the central core of signaling complex is dimeric.
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46
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Wynn EH, Sánchez-Andrade G, Carss KJ, Logan DW. Genomic variation in the vomeronasal receptor gene repertoires of inbred mice. BMC Genomics 2012; 13:415. [PMID: 22908939 PMCID: PMC3460788 DOI: 10.1186/1471-2164-13-415] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2012] [Accepted: 07/18/2012] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND Vomeronasal receptors (VRs), expressed in sensory neurons of the vomeronasal organ, are thought to bind pheromones and mediate innate behaviours. The mouse reference genome has over 360 functional VRs arranged in highly homologous clusters, but the vast majority are of unknown function. Differences in these receptors within and between closely related species of mice are likely to underpin a range of behavioural responses. To investigate these differences, we interrogated the VR gene repertoire from 17 inbred strains of mice using massively parallel sequencing. RESULTS Approximately half of the 6222 VR genes that we investigated could be successfully resolved, and those that were unambiguously mapped resulted in an extremely accurate dataset. Collectively VRs have over twice the coding sequence variation of the genome average; but we identify striking non-random distribution of these variants within and between genes, clusters, clades and functional classes of VRs. We show that functional VR gene repertoires differ considerably between different Mus subspecies and species, suggesting these receptors may play a role in mediating behavioural adaptations. Finally, we provide evidence that widely-used, highly inbred laboratory-derived strains have a greatly reduced, but not entirely redundant capacity for differential pheromone-mediated behaviours. CONCLUSIONS Together our results suggest that the unusually variable VR repertoires of mice have a significant role in encoding differences in olfactory-mediated responses and behaviours. Our dataset has expanded over nine fold the known number of mouse VR alleles, and will enable mechanistic analyses into the genetics of innate behavioural differences in mice.
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Affiliation(s)
| | | | - Keren J Carss
- Wellcome Trust Sanger Institute, Hinxton, Cambridge, UK
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Membrane-sensitive conformational states of helix 8 in the metabotropic Glu2 receptor, a class C GPCR. PLoS One 2012; 7:e42023. [PMID: 22870276 PMCID: PMC3411606 DOI: 10.1371/journal.pone.0042023] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 06/29/2012] [Indexed: 11/19/2022] Open
Abstract
The recent elucidation of the X-ray structure of several class A GPCRs clearly indicates that the amphipathic helix 8 (H8) is a conserved structural domain in most crystallized GPCRs. Very little is known about the presence and the possible role of an analogous H8 domain in the distantly related class C GPCRs. In this study, we investigated the structural properties for the H8 domain of the mGluR2 receptor, a class C GPCR, by applying extended molecular dynamics simulations. Our study indicates that the amphipathic H8 adopts membrane-sensitive conformational states, which depend on the membrane composition. Cholesterol-rich membranes stabilize the helical structure of H8 whereas cholesterol-depleted membranes induce a disruption of H8. The observed link between membrane cholesterol levels and H8 conformational states suggests that H8 behaves as a sensor of cholesterol concentration.
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48
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Taneera J, Jin Z, Jin Y, Muhammed SJ, Zhang E, Lang S, Salehi A, Korsgren O, Renström E, Groop L, Birnir B. γ-Aminobutyric acid (GABA) signalling in human pancreatic islets is altered in type 2 diabetes. Diabetologia 2012; 55:1985-94. [PMID: 22538358 PMCID: PMC3369140 DOI: 10.1007/s00125-012-2548-7] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 03/07/2012] [Indexed: 12/31/2022]
Abstract
AIMS/HYPOTHESIS γ-Aminobutyric acid (GABA) is a signalling molecule in the interstitial space in pancreatic islets. We examined the expression and function of the GABA signalling system components in human pancreatic islets from normoglycaemic and type 2 diabetic individuals. METHODS Expression of GABA signalling system components was studied by microarray, quantitative PCR analysis, immunohistochemistry and patch-clamp experiments on cells in intact islets. Hormone release was measured from intact islets. RESULTS The GABA signalling system was compromised in islets from type 2 diabetic individuals, where the expression of the genes encoding the α1, α2, β2 and β3 GABA(A) channel subunits was downregulated. GABA originating within the islets evoked tonic currents in the cells. The currents were enhanced by pentobarbital and inhibited by the GABA(A) receptor antagonist, SR95531. The effects of SR95531 on hormone release revealed that activation of GABA(A) channels (GABA(A) receptors) decreased both insulin and glucagon secretion. The GABA(B) receptor antagonist, CPG55845, increased insulin release in islets (16.7 mmol/l glucose) from normoglycaemic and type 2 diabetic individuals. CONCLUSIONS/INTERPRETATION Interstitial GABA activates GABA(A) channels and GABA(B) receptors and effectively modulates hormone release in islets from type 2 diabetic and normoglycaemic individuals.
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Affiliation(s)
- J. Taneera
- Lund University Diabetes Center, Department of Clinical Sciences, Diabetes & Endocrinology, University Hospital Malmö, Lund University, Malmö, Sweden
| | - Z. Jin
- Department of Neuroscience, Uppsala University, Box 593, 75124 Uppsala, Sweden
| | - Y. Jin
- Department of Neuroscience, Uppsala University, Box 593, 75124 Uppsala, Sweden
| | - S. J. Muhammed
- Department of Clinical Sciences, Islet Cell physiology, University Hospital Malmö, Lund University, Malmö, Sweden
| | - E. Zhang
- Department of Clinical Sciences, Islet Pathophysiology, University Hospital Malmö, Lund University, Malmö, 20502 Sweden
| | - S. Lang
- Department of Neuroscience, Uppsala University, Box 593, 75124 Uppsala, Sweden
- Lund University Diabetes Center, Department of Clinical Sciences, Diabetes & Endocrinology, University Hospital Malmö, Lund University, Malmö, Sweden
| | - A. Salehi
- Department of Clinical Sciences, Islet Cell physiology, University Hospital Malmö, Lund University, Malmö, Sweden
| | - O. Korsgren
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, 75185 Sweden
| | - E. Renström
- Department of Clinical Sciences, Islet Pathophysiology, University Hospital Malmö, Lund University, Malmö, 20502 Sweden
| | - L. Groop
- Lund University Diabetes Center, Department of Clinical Sciences, Diabetes & Endocrinology, University Hospital Malmö, Lund University, Malmö, Sweden
| | - B. Birnir
- Department of Neuroscience, Uppsala University, Box 593, 75124 Uppsala, Sweden
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Amalric M, Lopez S, Goudet C, Fisone G, Battaglia G, Nicoletti F, Pin JP, Acher FC. Group III and subtype 4 metabotropic glutamate receptor agonists: discovery and pathophysiological applications in Parkinson's disease. Neuropharmacology 2012; 66:53-64. [PMID: 22664304 DOI: 10.1016/j.neuropharm.2012.05.026] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 04/28/2012] [Accepted: 05/21/2012] [Indexed: 12/22/2022]
Abstract
Restoring the balance between excitatory and inhibitory circuits in the basal ganglia, following the loss of dopaminergic (DA) neurons of the substantia nigra pars compacta, represents a major challenge to treat patients affected by Parkinson's disease (PD). The imbalanced situation in favor of excitation in the disease state may also accelerate excitotoxic processes, thereby representing a potential target for neuroprotective therapies. Reducing the excitatory action of glutamate, the major excitatory neurotransmitter in the basal ganglia, should lead to symptomatic improvement for PD patients and may promote the survival of DA neurons. Recent studies have focused on the modulatory action of metabotropic glutamate (mGlu) receptors on neurodegenerative diseases including PD. Group III mGlu receptors, including subtypes 4, 7 and 8, are largely expressed in the basal ganglia. Recent studies highlight the use of selective mGlu4 receptor positive allosteric modulators (PAMs) for the treatment of PD. Here we review the effects of newly-designed group-III orthosteric agonists on neuroprotection, neurorestoration and reduction of l-DOPA induced dyskinesia in animal models of PD. The combination of orthosteric mGlu4 receptor selective agonists with PAMs may open new avenues for the symptomatic treatment of PD. This article is part of a Special Issue entitled 'Metabotropic Glutamate Receptors'.
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Affiliation(s)
- M Amalric
- Aix-Marseille University, CNRS UMR 7291, Laboratoire de Neurosciences Fonctionnelles, Case C, 3 Place Victor Hugo, 13331 Marseille Cedex 3, France.
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Gassmann M, Bettler B. Regulation of neuronal GABA(B) receptor functions by subunit composition. Nat Rev Neurosci 2012; 13:380-94. [PMID: 22595784 DOI: 10.1038/nrn3249] [Citation(s) in RCA: 245] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
GABA(B) receptors (GABA(B)Rs) are G protein-coupled receptors for GABA, the main inhibitory neurotransmitter in the CNS. In the past 5 years, notable advances have been made in our understanding of the molecular composition of these receptors. GABA(B)Rs are now known to comprise principal and auxiliary subunits that influence receptor properties in distinct ways. The principal subunits regulate the surface expression and the axonal versus dendritic distribution of these receptors, whereas the auxiliary subunits determine agonist potency and the kinetics of the receptor response. This Review summarizes current knowledge on how the subunit composition of GABA(B)Rs affects the distribution of these receptors, neuronal processes and higher brain functions.
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Affiliation(s)
- Martin Gassmann
- Department of Biomedicine, Institute of Physiology, University of Basel, Klingelbergstr. 50-70, 4056 Basel, Switzerland.
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