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O'Connor EC, Kambara K, Bertrand D. Advancements in the use of xenopus oocytes for modelling neurological disease for novel drug discovery. Expert Opin Drug Discov 2024; 19:173-187. [PMID: 37850233 DOI: 10.1080/17460441.2023.2270902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 10/11/2023] [Indexed: 10/19/2023]
Abstract
INTRODUCTION Introduced about 50 years ago, the model of Xenopus oocytes for the expression of recombinant proteins has gained a broad spectrum of applications. The authors herein review the benefits brought from using this model system, with a focus on modeling neurological disease mechanisms and application to drug discovery. AREAS COVERED Using multiple examples spanning from ligand gated ion channels to transporters, this review presents, in the light of the latest publications, the benefits offered from using Xenopus oocytes. Studies range from the characterization of gene mutations to the discovery of novel treatments for disorders of the central nervous system (CNS). EXPERT OPINION Development of new drugs targeting CNS disorders has been marked by failures in the translation from preclinical to clinical studies. As progress in genetics and molecular biology highlights large functional differences arising from a single to a few amino acid exchanges, the need for drug screening and functional testing against human proteins is increasing. The use of Xenopus oocytes to enable precise modeling and characterization of clinically relevant genetic variants constitutes a powerful model system that can be used to inform various aspects of CNS drug discovery and development.
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Affiliation(s)
- Eoin C O'Connor
- Roche Pharma Research and Early Development, Neuroscience & Rare Diseases, Roche Innovation Center Basel, Basel, Switzerland
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2
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GPR37 Receptors and Megalencephalic Leukoencephalopathy with Subcortical Cysts. Int J Mol Sci 2022; 23:ijms23105528. [PMID: 35628339 PMCID: PMC9144339 DOI: 10.3390/ijms23105528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 11/30/2022] Open
Abstract
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is a rare type of vacuolating leukodystrophy (white matter disorder), which is mainly caused by defects in MLC1 or glial cell adhesion molecule (GlialCAM) proteins. In addition, autoantibodies to GlialCAM are involved in the pathology of multiple sclerosis. MLC1 and GLIALCAM genes encode for membrane proteins of unknown function, which has been linked to the regulation of different ion channels and transporters, such as the chloride channel VRAC (volume regulated anion channel), ClC-2 (chloride channel 2), and connexin 43 or the Na+/K+-ATPase pump. However, the mechanisms by which MLC proteins regulate these ion channels and transporters, as well as the exact function of MLC proteins remain obscure. It has been suggested that MLC proteins might regulate signalling pathways, but the mechanisms involved are, at present, unknown. With the aim of answering these questions, we have recently described the brain GlialCAM interactome. Within the identified proteins, we could validate the interaction with several G protein-coupled receptors (GPCRs), including the orphan GPRC5B and the proposed prosaposin receptors GPR37L1 and GPR37. In this review, we summarize new aspects of the pathophysiology of MLC disease and key aspects of the interaction between GPR37 receptors and MLC proteins.
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Hertz E, Saarinen M, Svenningsson P. GM1 Is Cytoprotective in GPR37-Expressing Cells and Downregulates Signaling. Int J Mol Sci 2021; 22:ijms222312859. [PMID: 34884663 PMCID: PMC8657933 DOI: 10.3390/ijms222312859] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/15/2021] [Accepted: 11/17/2021] [Indexed: 01/02/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) are commonly pharmacologically modulated due to their ability to translate extracellular events to intracellular changes. Previously, studies have mostly focused on protein–protein interactions, but the focus has now expanded also to protein–lipid connections. GM1, a brain-expressed ganglioside known for neuroprotective effects, and GPR37, an orphan GPCR often reported as a potential drug target for diseases in the central nervous system, have been shown to form a complex. In this study, we looked into the functional effects. Endogenous GM1 was downregulated when stably overexpressing GPR37 in N2a cells (N2aGPR37-eGFP). However, exogenous GM1 specifically rescued N2aGPR37-eGFP from toxicity induced by the neurotoxin MPP+. The treatment did not alter transcription levels of GPR37 or the enzyme responsible for GM1 production, both potential mechanisms for the effect. However, GM1 treatment inhibited cAMP-dependent signaling from GPR37, here reported as potentially consecutively active, possibly contributing to the protective effects. We propose an interplay between GPR37 and GM1 as one of the many cytoprotective effects reported for GM1.
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Affiliation(s)
- Ellen Hertz
- Correspondence: (E.H.); (P.S.); Tel.: +46-8517-74-614 (E.H.)
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4
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Roy N, Parhar I. Habenula orphan G-protein coupled receptors in the pathophysiology of fear and anxiety. Neurosci Biobehav Rev 2021; 132:870-883. [PMID: 34801259 DOI: 10.1016/j.neubiorev.2021.11.008] [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: 08/30/2021] [Revised: 11/02/2021] [Accepted: 11/08/2021] [Indexed: 10/19/2022]
Abstract
The phasic emotion, fear, and the tonic emotion, anxiety, have been conventionally inspected in clinical frameworks to epitomize memory acquisition, storage, and retrieval. However, inappropriate expression of learned fear in a safe environment and its resistance to suppression is a cardinal feature of various fear-related disorders. A significant body of literature suggests the involvement of extra-amygdala circuitry in fear disorders. Consistent with this view, the present review underlies incentives for the association between the habenula and fear memory. G protein-coupled receptors (GPCRs) are important to understand the molecular mechanisms central to fear learning due to their neuromodulatory role. The efficacy of a pharmacological strategy aimed at exploiting habenular-GPCR desensitization machinery can serve as a therapeutic target combating the pathophysiology of fear disorders. Originating from this milieu, the conserved nature of orphan GPCRs in the brain, with some having the highest expression in the habenula can lead to recent endeavors in understanding its functionality in fear circuitry.
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Affiliation(s)
- Nisa Roy
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia.
| | - Ishwar Parhar
- Brain Research Institute, Jeffrey Cheah School of Medicine and Health Sciences, Monash University Malaysia, Bandar Sunway, Selangor, Malaysia.
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5
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Morató X, Garcia-Esparcia P, Argerich J, Llorens F, Zerr I, Paslawski W, Borràs E, Sabidó E, Petäjä-Repo UE, Fernández-Dueñas V, Ferrer I, Svenningsson P, Ciruela F. Ecto-GPR37: a potential biomarker for Parkinson's disease. Transl Neurodegener 2021; 10:8. [PMID: 33637132 PMCID: PMC7908677 DOI: 10.1186/s40035-021-00232-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 02/08/2021] [Indexed: 11/15/2022] Open
Abstract
Objective α-Synuclein has been studied as a potential biomarker for Parkinson’s disease (PD) with no concluding results. Accordingly, there is an urgent need to find out reliable specific biomarkers for PD. GPR37 is an orphan G protein-coupled receptor that toxically accumulates in autosomal recessive juvenile parkinsonism. Here, we investigated whether GPR37 is upregulated in sporadic PD, and thus a suitable potential biomarker for PD. Methods GPR37 protein density and mRNA expression in postmortem substantia nigra (SN) from PD patients were analysed by immunoblot and RT-qPCR, respectively. The presence of peptides from the N-terminus-cleaved domain of GPR37 (i.e. ecto-GPR37) in human cerebrospinal fluid (CSF) was determined by liquid chromatography-mass spectrometric analysis. An engineered in-house nanoluciferase-based immunoassay was used to quantify ecto-GPR37 in CSF samples from neurological control (NC) subjects, PD patients and Alzheimer’s disease (AD) patients. Results GPR37 protein density and mRNA expression were significantly augmented in sporadic PD. Increased amounts of ecto-GPR37 peptides in the CSF samples from PD patients were identified by mass spectrometry and quantified by the in-house ELISA method. However, the CSF total α-synuclein level in PD patients did not differ from that in NC subjects. Similarly, the cortical GPR37 mRNA expression and CSF ecto-GPR37 levels in AD patients were also unaltered. Conclusion GPR37 expression is increased in SN of sporadic PD patients. The ecto-GPR37 peptides are significantly increased in the CSF of PD patients, but not in AD patients. These results open perspectives and encourage further clinical studies to confirm the validity and utility of ecto-GPR37 as a potential PD biomarker. Supplementary Information The online version contains supplementary material available at 10.1186/s40035-021-00232-7.
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Affiliation(s)
- Xavier Morató
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain.,Neuroscience Program, Bellvitge Biomedical Research Institute, IDIBELL, L'Hospitalet de Llobregat, Spain.,Section of Neurology, Department of Clinical Neuroscience, Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Paula Garcia-Esparcia
- Neuroscience Program, Bellvitge Biomedical Research Institute, IDIBELL, L'Hospitalet de Llobregat, Spain.,Neuropathology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain.,CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto Carlos III, Madrid, Spain
| | - Josep Argerich
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain.,Neuroscience Program, Bellvitge Biomedical Research Institute, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Franc Llorens
- Neuroscience Program, Bellvitge Biomedical Research Institute, IDIBELL, L'Hospitalet de Llobregat, Spain.,Neuropathology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain.,CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto Carlos III, Madrid, Spain.,Department of Neurology, Clinical Dementia Center and National Reference Center for CJD Surveillance, University Medical School, Göttingen, Germany
| | - Inga Zerr
- Department of Neurology, Clinical Dementia Center and National Reference Center for CJD Surveillance, University Medical School, Göttingen, Germany.,German Center for Neurodegenerative Diseases, Göttingen, Germany
| | - Wojciech Paslawski
- Section of Neurology, Department of Clinical Neuroscience, Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Eva Borràs
- Proteomics Unit, Center for Genomic Regulation, Barcelona, Spain.,Proteomics Unit, Universitat Pompeu Fabra, Barcelona, Spain
| | - Eduard Sabidó
- Proteomics Unit, Center for Genomic Regulation, Barcelona, Spain.,Proteomics Unit, Universitat Pompeu Fabra, Barcelona, Spain
| | - Ulla E Petäjä-Repo
- Research Unit of Biomedicine, Medical Research Center Oulu, University of Oulu, Oulu, Finland
| | - Víctor Fernández-Dueñas
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain.,Neuroscience Program, Bellvitge Biomedical Research Institute, IDIBELL, L'Hospitalet de Llobregat, Spain
| | - Isidro Ferrer
- Neuroscience Program, Bellvitge Biomedical Research Institute, IDIBELL, L'Hospitalet de Llobregat, Spain.,Neuropathology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain.,CIBERNED, Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas, Instituto Carlos III, Madrid, Spain
| | - Per Svenningsson
- Section of Neurology, Department of Clinical Neuroscience, Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Francisco Ciruela
- Pharmacology Unit, Department of Pathology and Experimental Therapeutics, Faculty of Medicine and Health Sciences, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Spain. .,Neuroscience Program, Bellvitge Biomedical Research Institute, IDIBELL, L'Hospitalet de Llobregat, Spain.
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6
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Watkins LR, Orlandi C. Orphan G Protein Coupled Receptors in Affective Disorders. Genes (Basel) 2020; 11:E694. [PMID: 32599826 PMCID: PMC7349732 DOI: 10.3390/genes11060694] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 06/20/2020] [Accepted: 06/21/2020] [Indexed: 12/12/2022] Open
Abstract
G protein coupled receptors (GPCRs) are the main mediators of signal transduction in the central nervous system. Therefore, it is not surprising that many GPCRs have long been investigated for their role in the development of anxiety and mood disorders, as well as in the mechanism of action of antidepressant therapies. Importantly, the endogenous ligands for a large group of GPCRs have not yet been identified and are therefore known as orphan GPCRs (oGPCRs). Nonetheless, growing evidence from animal studies, together with genome wide association studies (GWAS) and post-mortem transcriptomic analysis in patients, pointed at many oGPCRs as potential pharmacological targets. Among these discoveries, we summarize in this review how emotional behaviors are modulated by the following oGPCRs: ADGRB2 (BAI2), ADGRG1 (GPR56), GPR3, GPR26, GPR37, GPR50, GPR52, GPR61, GPR62, GPR88, GPR135, GPR158, and GPRC5B.
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Affiliation(s)
| | - Cesare Orlandi
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA;
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Park J, Langmead CJ, Riddy DM. New Advances in Targeting the Resolution of Inflammation: Implications for Specialized Pro-Resolving Mediator GPCR Drug Discovery. ACS Pharmacol Transl Sci 2020; 3:88-106. [PMID: 32259091 DOI: 10.1021/acsptsci.9b00075] [Citation(s) in RCA: 70] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Indexed: 12/19/2022]
Abstract
Chronic inflammation is a component of numerous diseases including autoimmune, metabolic, neurodegenerative, and cancer. The discovery and characterization of specialized pro-resolving mediators (SPMs) critical to the resolution of inflammation, and their cognate G protein-coupled receptors (GPCRs) has led to a significant increase in the understanding of this physiological process. Approximately 20 ligands, including lipoxins, resolvins, maresins, and protectins, and 6 receptors (FPR2/ALX, GPR32, GPR18, chemerin1, BLT1, and GPR37) have been identified highlighting the complex and multilayered nature of resolution. Therapeutic efforts in targeting these receptors have proved challenging, with very few ligands apparently progressing through to preclinical or clinical development. To date, some knowledge gaps remain in the understanding of how the activation of these receptors, and their downstream signaling, results in efficient resolution via apoptosis, phagocytosis, and efferocytosis of polymorphonuclear leukocytes (mainly neutrophils) and macrophages. SPMs bind and activate multiple receptors (ligand poly-pharmacology), while most receptors are activated by multiple ligands (receptor pleiotropy). In addition, allosteric binding sites have been identified signifying the capacity of more than one ligand to bind simultaneously. These fundamental characteristics of SPM receptors enable alternative targeting strategies to be considered, including biased signaling and allosteric modulation. This review describes those ligands and receptors involved in the resolution of inflammation, and highlights the most recent clinical trial results. Furthermore, we describe alternative mechanisms by which these SPM receptors could be targeted, paving the way for the identification of new therapeutics, perhaps with greater efficacy and fidelity.
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Affiliation(s)
- Julia Park
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Christopher J Langmead
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
| | - Darren M Riddy
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria 3052, Australia
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8
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McCrary MR, Jiang MQ, Giddens MM, Zhang JY, Owino S, Wei ZZ, Zhong W, Gu X, Xin H, Hall RA, Wei L, Yu SP. Protective effects of GPR37 via regulation of inflammation and multiple cell death pathways after ischemic stroke in mice. FASEB J 2019; 33:10680-10691. [PMID: 31268736 PMCID: PMC6766648 DOI: 10.1096/fj.201900070r] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 06/04/2019] [Indexed: 12/15/2022]
Abstract
GPCR 37 (GPR37) is a GPCR expressed in the CNS; its physiological and pathophysiological functions are largely unknown. We tested the role of GPR37 in the ischemic brain of GPR37 knockout (KO) mice, exploring the idea that GPR37 might be protective against ischemic damage. In an ischemic stroke model, GPR37 KO mice exhibited increased infarction and cell death compared with wild-type (WT) mice, measured by 2,3,5-triphenyl-2H-tetrazolium chloride and TUNEL staining 24 h after stroke. Moreover, more severe functional deficits were detected in GPR37 KO mice in the adhesive-removal and corner tests. In the peri-infarct region of GPR37 KO mice, there was significantly more apoptotic and autophagic cell death accompanied by caspase-3 activation and attenuated mechanistic target of rapamycin signaling. GPR37 deletion attenuated astrocyte activation and astrogliosis compared with WT stroke controls 24-72 h after stroke. Immunohistochemical staining showed more ionized calcium-binding adapter molecule 1-positive cells in the ischemic cortex of GPR37 KO mice, and RT-PCR identified an enrichment of M1-type microglia or macrophage markers in the GPR37 KO ischemic cortex. Western blotting demonstrated higher levels of inflammatory factors IL-1β, IL-6, monocyte chemoattractant protein, and macrophage inflammatory protein-1α in GPR37-KO mice after ischemia. Thus, GPR37 plays a multifaceted role after stroke, suggesting a novel target for stroke therapy.-McCrary, M. R., Jiang, M. Q., Giddens, M. M., Zhang, J. Y., Owino, S., Wei, Z. Z., Zhong, W., Gu, X., Xin, H., Hall, R. A., Wei, L., Yu, S. P. Protective effects of GPR37 via regulation of inflammation and multiple cell death pathways after ischemic stroke in mice.
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Affiliation(s)
- Myles R. McCrary
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Michael Q. Jiang
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Michelle M. Giddens
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - James Y. Zhang
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Sharon Owino
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Zheng Z. Wei
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Weiwei Zhong
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Xiaohuan Gu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Huang Xin
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Randy A. Hall
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Ling Wei
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Shan P. Yu
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia, USA
- Center for Visual and Neurocognitive Rehabilitation, Atlanta Veterans Affairs Medical Center, Decatur, Georgia, USA
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Saadi H, Shan Y, Marazziti D, Wray S. GPR37 Signaling Modulates Migration of Olfactory Ensheathing Cells and Gonadotropin Releasing Hormone Cells in Mice. Front Cell Neurosci 2019; 13:200. [PMID: 31143101 PMCID: PMC6521704 DOI: 10.3389/fncel.2019.00200] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 04/18/2019] [Indexed: 01/15/2023] Open
Abstract
Gonadotropin releasing hormone (GnRH) neurons, part of the hypothalamic-pituitary-gonadal axis, regulate reproduction. Prenatally, GnRH neurons migrate into the brain from the nasal placode along terminal nerve fibers, intermixed with olfactory sensory axons and olfactory ensheathing cells (OECs). An expression analysis from embryonic GnRH neurons identified the G protein-coupled receptor 37 (GPR37 or PAEL-r). GPR37 has been linked to (1) juvenile Parkinson's disease in humans, (2) oligodendrocyte differentiation, and (3) Wnt/β-catenin signaling during neurogenesis. In this study, the role of GPR37 was investigated in the developing GnRH/olfactory system. PCR and immunocytochemistry confirmed expression of GPR37 in migrating GnRH neurons as well as in OECs. Inhibition of GPR37 signaling in nasal explants attenuated GnRH neuronal migration and OEC movement. Examination of GPR37 deficient mice revealed a decrease in the olfactory bulb nerve layer and attenuated/delayed maturation and migration of GnRH neurons into the brain. These data demonstrate a developmental role for GPR37 signaling in neural migration. SIGNIFICANCE STATEMENT Reproduction is controlled by gonadotrophin releasing hormone (GnRH) neurons located in the central nervous system. Embryonically, GnRH neurons originate in the nasal/olfactory placode and migrate into the brain on axonal tracks from cells in the vomeronasal organ, intermixed with olfactory sensory axons and olfactory ensheathing cells (OECs). An expression analysis from embryonic GnRH neurons identified the G protein-coupled receptor 37. Here we show that inhibition of GPR37 signaling in nasal explants and mutant mice attenuated GnRH neuronal migration. Signaling via GPR37 also perturbed OEC movement, resulting in a decrease in the olfactory bulb nerve layer in vivo. Together, these results identify a new role for GPR37 signaling during development - modulating cell migration.
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Affiliation(s)
- Hassan Saadi
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Yufei Shan
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
| | - Daniela Marazziti
- Consiglio Nazionale delle Ricerche, Emma-Infrafrontier-Impc, Istituto di Biologia Cellulare e Neurobiologia, Monterotondo Scalo, Rome, Italy
| | - Susan Wray
- Cellular and Developmental Neurobiology Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States
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10
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Zheng W, Zhou J, Luan Y, Yang J, Ge Y, Wang M, Wu B, Wu Z, Chen X, Li F, Li Z, Vakal S, Guo W, Chen JF. Spatiotemporal Control of GPR37 Signaling and Its Behavioral Effects by Optogenetics. Front Mol Neurosci 2018; 11:95. [PMID: 29643766 PMCID: PMC5882850 DOI: 10.3389/fnmol.2018.00095] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 03/12/2018] [Indexed: 12/18/2022] Open
Abstract
Despite the progress in deorphanization of G Protein-Coupled Receptors (GPCRs), ≈100 GPCRs are still classified as orphan receptors without identified endogenous ligands and with unknown physiological functions. The lack of endogenous ligands triggering GPCR signaling has hampered the study of orphan GPCR functions. Using GPR37 as an example, we provide here the first demonstration of the channelrhodopsin 2 (ChR2)-GPCR approach to bypass the endogenous ligand and selectively activate the orphan GPCR signal by optogenetics. Inspired by the opto-XR approach, we designed the ChR2-GPR37 chimera, in which the corresponding parts of GPR37 replaced the intracellular portions of ChR2. We showed that optogenetic activation of ChR2/opto-GPR37 elicited specific GPR37 signaling, as evidenced by reduced cAMP level, enhanced ERK phosphorylation and increased motor activity, confirming the specificity of opto-GPR37 signaling. Besides, optogenetic activation of opto-GPR37 uncovered novel aspects of GPR37 signaling (such as IP-3 signaling) and anxiety-related behavior. Optogenetic activation of opto-GPR37 permits the causal analysis of GPR37 activity in the defined cells and behavioral responses of freely moving animals. Importantly, given the evolutionarily conserved seven-helix transmembrane structures of ChR2 and orphan GPCRs, we propose that opto-GPR37 approach can be readily applied to other orphan GPCRs for their deorphanization in freely moving animals.
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Affiliation(s)
- Wu Zheng
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Jianhong Zhou
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Yanan Luan
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Jianglan Yang
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Yuanyuan Ge
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Muran Wang
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Beibei Wu
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Zhongnan Wu
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Xingjun Chen
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Fei Li
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Zhihui Li
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Sergii Vakal
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China
| | - Wei Guo
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Optometry & Vision Science, Wenzhou, China
| | - Jiang-Fan Chen
- Molecular Neuropharmacology Laboratory, School of Optometry and Ophthalmology and Eye Hospital, Wenzhou Medical University, Wenzhou, China.,State Key Laboratory of Optometry & Vision Science, Wenzhou, China.,Department of Neurology, Boston University School of Medicine, Boston University, Boston, MA, United States
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11
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Alavi MS, Shamsizadeh A, Azhdari-Zarmehri H, Roohbakhsh A. Orphan G protein-coupled receptors: The role in CNS disorders. Biomed Pharmacother 2017; 98:222-232. [PMID: 29268243 DOI: 10.1016/j.biopha.2017.12.056] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Revised: 12/12/2017] [Accepted: 12/14/2017] [Indexed: 12/20/2022] Open
Abstract
There are various types of receptors in the central nervous system (CNS). G protein-coupled receptors (GPCRs) have the highest expression with a wide range of physiological functions. A newer sub group of these receptors namely orphan GPCRs have been discovered. GPR3, GPR6, GPR17, GPR26, GPR37, GPR39, GPR40, GPR50, GPR52, GPR54, GPR55, GPR85, GPR88, GPR103, and GPR139 are the selected orphan GPCRs for this article. Their roles in the central nervous system have not been understood well so far. However, recent studies show that they may have very important functions in the CNS. Hence, in the present study, we reviewed most recent findings regarding the physiological roles of the selected orphan GPCRs in the CNS. After a brief presentation of each receptor, considering the results from genetic and pharmacological manipulation of the receptors, their roles in the pathophysiology of different diseases and disorders including anxiety, depression, schizophrenia, epilepsy, Alzheimer's disease, Parkinson's disease, and substance abuse will be discussed. At present, our knowledge regarding the role of GPCRs in the brain is very limited. However, previous limited studies show that orphan GPCRs have an important place in psychopharmacology and these receptors are potential new targets for the treatment of major CNS diseases.
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Affiliation(s)
- Mohaddeseh Sadat Alavi
- Division of Neurocognitive Sciences, Psychiatry and Behavioral Sciences Research Center, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Ali Shamsizadeh
- Physiology-Pharmacology Research Center, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Hassan Azhdari-Zarmehri
- Department of Basic Medical Sciences and Neuroscience Research Center, Torbat Heydariyeh University of Medical Sciences, Torbat Heydariyeh, Iran
| | - Ali Roohbakhsh
- Pharmaceutical Research Center, Pharmaceutical Technology Institute, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Pharmacodynamics and Toxicology, School of Pharmacy, Mashhad University of Medical Sciences, Mashhad, Iran.
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12
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Morató X, Luján R, López-Cano M, Gandía J, Stagljar I, Watanabe M, Cunha RA, Fernández-Dueñas V, Ciruela F. The Parkinson's disease-associated GPR37 receptor interacts with striatal adenosine A 2A receptor controlling its cell surface expression and function in vivo. Sci Rep 2017; 7:9452. [PMID: 28842709 PMCID: PMC5573386 DOI: 10.1038/s41598-017-10147-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 08/04/2017] [Indexed: 11/24/2022] Open
Abstract
G protein-coupled receptor 37 (GPR37) is an orphan receptor associated to Parkinson’s disease (PD) neuropathology. Here, we identified GPR37 as an inhibitor of adenosine A2A receptor (A2AR) cell surface expression and function in vivo. In addition, we showed that GPR37 and A2AR do oligomerize in the striatum. Thus, a close proximity of GPR37 and A2AR at the postsynaptic level of striatal synapses was observed by double-labelling post-embedding immunogold detection. Indeed, the direct receptor-receptor interaction was further substantiated by proximity ligation in situ assay. Interestingly, GPR37 deletion promoted striatal A2AR cell surface expression that correlated well with an increased A2AR agonist-mediated cAMP accumulation, both in primary striatal neurons and nerve terminals. Furthermore, GPR37−/− mice showed enhanced A2AR agonist-induced catalepsy and an increased response to A2AR antagonist-mediated locomotor activity. Overall, these results revealed a key role for GPR37 controlling A2AR biology in the striatum, which may be relevant for PD management.
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Affiliation(s)
- Xavier Morató
- Unitat de Farmacologia, Departament Patologia i Terapéutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Rafael Luján
- IDINE, Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, Albacete, Spain
| | - Marc López-Cano
- Unitat de Farmacologia, Departament Patologia i Terapéutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Jorge Gandía
- Unitat de Farmacologia, Departament Patologia i Terapéutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain
| | - Igor Stagljar
- Donnelly Centre, Department of Molecular Genetics, Department of Biochemistry, University of Toronto, Toronto, M5S 3E1, Canada
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University School of Medicine, Sapporo, 060-0818, Japan
| | - Rodrigo A Cunha
- CNC-Center for Neuroscience and Cell Biology, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Víctor Fernández-Dueñas
- Unitat de Farmacologia, Departament Patologia i Terapéutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain. .,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapéutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain. .,Institut de Neurociències, Universitat de Barcelona, Barcelona, Spain.
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13
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Smith BM, Giddens MM, Neil J, Owino S, Nguyen TT, Duong D, Li F, Hall RA. Mice lacking Gpr37 exhibit decreased expression of the myelin-associated glycoprotein MAG and increased susceptibility to demyelination. Neuroscience 2017. [PMID: 28642167 DOI: 10.1016/j.neuroscience.2017.06.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
GPR37 is an orphan G protein-coupled receptor that is predominantly expressed in the brain and found at particularly high levels in oligodendrocytes. GPR37 has been shown to exert effects on oligodendrocyte differentiation and myelination during development, but the molecular basis of these actions is incompletely understood and moreover nothing is known about the potential role(s) of this receptor under demyelinating conditions. To shed light on the fundamental biology of GPR37, we performed proteomic studies comparing protein expression levels in the brains of mice lacking GPR37 and its close relative GPR37-like 1 (GPR37L1). These studies revealed that one of the proteins most sharply decreased in the brains of Gpr37/Gpr37L1 double knockout mice is the myelin-associated glycoprotein MAG. Follow-up Western blot studies confirmed this finding and demonstrated that genetic deletion of Gpr37, but not Gpr37L1, results in strikingly decreased brain expression of MAG. Further in vitro studies demonstrated that GPR37 and MAG form a complex when expressed together in cells. As loss of MAG has previously been shown to result in increased susceptibility to brain insults, we additionally assessed Gpr37-knockout (Gpr37-/-) vs. wild-type mice in the cuprizone model of demyelination. These studies revealed that Gpr37-/- mice exhibit dramatically increased loss of myelin in response to cuprizone, yet do not show any increased loss of oligodendrocyte precursor cells or mature oligodendrocytes. These findings reveal that loss of GPR37 alters oligodendrocyte physiology and increases susceptibility to demyelination, indicating that GPR37 could be a potential drug target for the treatment of demyelinating diseases such as multiple sclerosis.
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Affiliation(s)
- Brilee M Smith
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Michelle M Giddens
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | - Jessica Neil
- Neurorepair Therapeutics, Inc., Research Triangle Park, NC, USA
| | - Sharon Owino
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA
| | | | - Duc Duong
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, USA
| | - Fengqiao Li
- Neurorepair Therapeutics, Inc., Research Triangle Park, NC, USA
| | - Randy A Hall
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA, USA.
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14
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Leinartaité L, Svenningsson P. Folding Underlies Bidirectional Role of GPR37/Pael-R in Parkinson Disease. Trends Pharmacol Sci 2017. [PMID: 28629580 DOI: 10.1016/j.tips.2017.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Since conformational flexibility, which is required for the function of a protein, comes at the expense of structural stability, many proteins, including G-protein-coupled receptors (GPCRs), are under constant risk of misfolding and aggregation. In this regard GPR37 (also named PAEL-R and ETBR-LP-1) takes a prominent role, particularly in relation to Parkinson disease (PD). GPR37 is a substrate for parkin and accumulates abnormally in autosomal recessive juvenile parkinsonism, contributing to endoplasmic reticulum stress and death of dopaminergic neurons. GPR37 also constitutes a core structure of Lewy bodies, demonstrating a more general involvement in PD pathology. However, if folded and matured properly, GPR37 seems to be neuroprotective. Moreover, GPR37 modulates functionality of the dopamine transporter and the dopamine D2 receptor and stimulates dopamine neurotransmission. Here we review the multiple roles of GPR37 with relevance to potential disease modification and symptomatic therapies of PD and highlight unsolved issues in this field.
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Affiliation(s)
- Lina Leinartaité
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, SE-171 76, Stockholm, Sweden.
| | - Per Svenningsson
- Department of Clinical Neuroscience, Center for Molecular Medicine, Karolinska Institutet, SE-171 76, Stockholm, Sweden.
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15
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The interaction between host genetics and the microbiome in the pathogenesis of spondyloarthropathies. Curr Opin Rheumatol 2017; 28:405-12. [PMID: 27152700 DOI: 10.1097/bor.0000000000000299] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW The intestinal microbiome is increasingly implicated in the pathogenesis of ankylosing spondylitis, reactive arthritis, and other diseases collectively known as the spondyloarthropathies (SpAs). In common with other complex inflammatory diseases, SpAs have both a strong genetic and environmental component. Recent genetic studies have highlighted host pathways that may intersect the host-microbiota interaction and offer novel paradigms to understand the pathophysiology of these diseases. RECENT FINDINGS Genetic association studies have identified genes such as RUNX3, PTPEN2, and IL-33 as susceptibility loci for SpAs. Functional studies in humans have extended knowledge of established genetic risk factors for ankylosing spondylitis that include ERAP1, ERAP2, and interleukin-23R. Recent basic research has identified new mechanisms that regulate host immune responses to the microbiota that conceivably may be dysregulated in SpA. SUMMARY Intestinal barrier function, deletional tolerance, Th17 signature response, and endoplasmic reticulum stress pathways have been recently linked to SpA. Dysregulated immune responses to the gut microbiota and an altered microbial community structure are shared features of SpA. Although the cause-effect dynamic of this relationship remains equivocal, it nonetheless has major implications for both intestinal and extra-intestinal pathology observed in SpA.
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16
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Rial D, Morató X, Real JI, Gonçalves FQ, Stagljar I, Pereira FC, Fernández-Dueñas V, Cunha RA, Ciruela F. Parkinson's disease-associated GPR37 receptor regulates cocaine-mediated synaptic depression in corticostriatal synapses. Neurosci Lett 2016; 638:162-166. [PMID: 28007645 DOI: 10.1016/j.neulet.2016.12.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 12/11/2016] [Accepted: 12/13/2016] [Indexed: 11/15/2022]
Abstract
GPR37 is an orphan G protein-coupled receptor highly expressed in the brain. The precise function of GPR37 is still unknown, but a number of evidences indicate it modulates the dopaminergic system. Here, we aimed to determine the role of GPR37 on the control of cocaine-mediated electrophysiological effects (synaptic transmission and short-term plasticity) in corticostriatal synapses. Accordingly, we evaluated basal synaptic transmission and paired-pulse stimulation (PPS) in wild-type and GPR37KO mice slices. Regardless of the genotype, a low concentration of cocaine (2μM) did not modify basal synaptic transmission. Conversely, a higher dose of cocaine (30μM) decreased synaptic transmission in both genotypes, although with different intensities: approximately 30% in slices from wild-type mice and 45% in slices from GPR37-KO mice. On the other hand, no differences in PPS ratio were observed between wild-type and GPR37-KO cocaine-treated mice. Overall, our data suggest that GPR37 is involved in cocaine-induced modification of basal synaptic transmission without modifying cocaine effects in short-term plasticity.
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Affiliation(s)
- Daniel Rial
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Xavier Morató
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain; Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
| | - Joana I Real
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Francisco Q Gonçalves
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Igor Stagljar
- Department of Biochemistry and Department of Molecular Genetics, Donnelly Centre, University of Toronto, Toronto, Ontario, M5S 3E1, Canada, Canada
| | | | - Víctor Fernández-Dueñas
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain; Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain
| | - Rodrigo A Cunha
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal; Faculty of Medicine, University of Coimbra, Portugal
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain; Institut de Neurosciències, Universitat de Barcelona, Barcelona, Spain.
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17
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Mattila SO, Tuusa JT, Petäjä-Repo UE. The Parkinson's-disease-associated receptor GPR37 undergoes metalloproteinase-mediated N-terminal cleavage and ectodomain shedding. J Cell Sci 2016; 129:1366-77. [PMID: 26869225 DOI: 10.1242/jcs.176115] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 02/08/2016] [Indexed: 12/20/2022] Open
Abstract
The G-protein-coupled receptor 37 ( GPR37) has been implicated in the juvenile form of Parkinson's disease, in dopamine signalling and in the survival of dopaminergic cells in animal models. The structure and function of the receptor, however, have remained enigmatic. Here, we demonstrate that although GPR37 matures and is exported from the endoplasmic reticulum in a normal manner upon heterologous expression in HEK293 and SH-SY5Y cells, its long extracellular N-terminus is subject to metalloproteinase-mediated limited proteolysis between E167 and Q168. The proteolytic processing is a rapid and efficient process that occurs constitutively. Moreover, the GPR37 ectodomain is released from cells by shedding, a phenomenon rarely described for GPCRs. Immunofluorescence microscopy further established that although full-length receptors are present in the secretory pathway until the trans-Golgi network, GPR37 is expressed at the cell surface predominantly in the N-terminally truncated form. This notion was verified by flow cytometry and cell surface biotinylation assays. These new findings on the GPR37 N-terminal limited proteolysis may help us to understand the role of this GPCR in the pathophysiology of Parkinson's disease and in neuronal function in general.
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Affiliation(s)
- S Orvokki Mattila
- Medical Research Center Oulu, and Cancer and Translational Medicine Research Unit, University of Oulu, Oulu FI-90014, Finland
| | - Jussi T Tuusa
- Medical Research Center Oulu, and Cancer and Translational Medicine Research Unit, University of Oulu, Oulu FI-90014, Finland
| | - Ulla E Petäjä-Repo
- Medical Research Center Oulu, and Cancer and Translational Medicine Research Unit, University of Oulu, Oulu FI-90014, Finland
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18
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Smith NJ. Drug Discovery Opportunities at the Endothelin B Receptor-Related Orphan G Protein-Coupled Receptors, GPR37 and GPR37L1. Front Pharmacol 2015; 6:275. [PMID: 26635605 PMCID: PMC4648071 DOI: 10.3389/fphar.2015.00275] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Accepted: 10/30/2015] [Indexed: 01/01/2023] Open
Abstract
Orphan G protein-coupled receptors (GPCRs) represent a largely untapped resource for the treatment of a variety of diseases, despite sophisticated advances in drug discovery. Two promising orphan GPCRs are the endothelin B receptor-like proteins, GPR37 [ET(B)R-LP, Pael-R] and GPR37L1 [ET(B)R-LP-2]. Originally identified through searches for homologs of endothelin and bombesin receptors, neither GPR37 nor GPR37L1 were found to bind endothelins or related peptides. Instead, GPR37 was proposed to be activated by head activator (HA) and both GPR37 and GPR37L1 have been linked to the neuropeptides prosaposin and prosaptide, although these pairings are yet to be universally acknowledged. Both orphan GPCRs are widely expressed in the brain, where GPR37 has received the most attention for its link to Parkinson’s disease and parkinsonism, while GPR37L1 deletion leads to precocious cerebellar development and hypertension. In this review, the existing pharmacology and physiology of GPR37 and GPR37L1 is discussed and the potential therapeutic benefits of targeting these receptors are explored.
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Affiliation(s)
- Nicola J Smith
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute , Darlinghurst, NSW, Australia ; St. Vincent's Clinical School, University of New South Wales , Darlinghurst, NSW, Australia
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19
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Lopes JP, Morató X, Souza C, Pinhal C, Machado NJ, Canas PM, Silva HB, Stagljar I, Gandía J, Fernández-Dueñas V, Luján R, Cunha RA, Ciruela F. The role of parkinson's disease-associated receptor GPR37 in the hippocampus: functional interplay with the adenosinergic system. J Neurochem 2015; 134:135-46. [PMID: 25824528 DOI: 10.1111/jnc.13109] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2014] [Revised: 02/19/2015] [Accepted: 03/18/2015] [Indexed: 12/22/2022]
Abstract
GPR37 is an orphan G protein-coupled receptor mostly enriched in brain areas such as the cerebellum, striatum, and hippocampus. Identified as a substrate of parkin, GPR37 has been suggested to play a role in Parkinson's disease. Distributed throughout the brain, the function of GPR37, however, remains unknown. We now provide the first mapping of GPR37 within the hippocampus, where GPR37 is widely expressed and localized at the level of the extrasynaptic plasma membrane of dendritic spines, dendritic shafts, and axon terminals. GPR37 per se does not appear to play a role in learning and memory, since knocking out GPR37 (GPR37-KO) did not alter the performance in different hippocampal-related memory tasks. This is in agreement with slice electrophysiology experiments showing no differences both in short-term plasticity paired-pulse facilitation and long-term potentiation between WT and GPR37-KO mice. However, we report a potential functional interaction between GPR37 and adenosine A2A receptors (A2 A R) in the hippocampus, with A2 A R modulating the GPR37-associated phenotype. Thus, the absence of GPR37 appeared to sensitize mice to hippocampal A2 A R-mediated signaling, as observed by the effect of the A2 A R antagonist SCH58261 increasing synaptic depotentiation, reducing novel object recognition memory and reverting the anxiolytic effect of GPR37 deletion. Collectively, these findings afford insight into the localization and role of the orphan GPR37 within the hippocampus with potential involvement in A2 A R function (i.e., A2 A R sensitization). GPR37 is an orphan G protein-coupled receptor widely expressed in the hippocampus and localized at the level of the extrasynaptic plasma membrane of dendritic spines, dendritic shafts and axon terminals. This orphan receptor per se does not appear to directly control the learning and memory processes; however knocking-out GPR37 triggers anxiolytic-like effects and sensitizes mice to hippocampal A2A R-mediated signalling.
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Affiliation(s)
- João P Lopes
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Xavier Morató
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain
| | - Carolina Souza
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Cindy Pinhal
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Nuno J Machado
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Paula M Canas
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Henrique B Silva
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Igor Stagljar
- Department of Biochemistry and Department of Molecular Genetics, Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Jorge Gandía
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain
| | - Víctor Fernández-Dueñas
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain
| | - Rafael Luján
- Departamento de Ciencias Médicas, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina, Universidad Castilla-La Mancha, Albacete, Spain
| | - Rodrigo A Cunha
- CNC-Center for Neurosciences and Cell Biology and Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, Spain.,Department of Physiology, Faculty of Sciences, University of Ghent, Gent, Belgium
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20
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Gandía J, Morató X, Stagljar I, Fernández-Dueñas V, Ciruela F. Adenosine A2A receptor-mediated control of pilocarpine-induced tremulous jaw movements is Parkinson's disease-associated GPR37 receptor-dependent. Behav Brain Res 2015; 288:103-6. [PMID: 25862943 DOI: 10.1016/j.bbr.2015.04.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Revised: 03/28/2015] [Accepted: 04/02/2015] [Indexed: 01/15/2023]
Abstract
GPR37, also known as parkin associated endothelin-like receptor (Pael-R), is an orphan GPCR that aggregates intracellularly in a juvenile form of Parkinson's disease. However, little is known about the function of this orphan receptor. Here, using a model for parkisonian tremor, the pilocarpine-induced tremulous jaw movements (TJMs), we show that the deletion of GPR37 attenuated the TJMs in response to this cholinomimetic. Interestingly, the control that adenosine A2A receptor exerted over TJMs was lost in the absence of GPR37, thus pointing to a pivotal role of this orphan receptor in the adenosinergic control of parkinsonian tremor.
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Affiliation(s)
- Jorge Gandía
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain
| | - Xavier Morató
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain
| | - Igor Stagljar
- Department of Biochemistry, Donnelly Centre, University of Toronto, Toronto, Ontario, Canada; Department of Molecular Genetics, Donnelly Centre, University of Toronto, Toronto, Ontario, Canada
| | - Víctor Fernández-Dueñas
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain.
| | - Francisco Ciruela
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, L'Hospitalet de Llobregat, 08907 Barcelona, Spain; Department of Physiology, Faculty of Sciences, University of Ghent, 9000 Gent, Belgium.
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21
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Meyer RC, Giddens MM, Coleman BM, Hall RA. The protective role of prosaposin and its receptors in the nervous system. Brain Res 2014; 1585:1-12. [PMID: 25130661 DOI: 10.1016/j.brainres.2014.08.022] [Citation(s) in RCA: 87] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 07/18/2014] [Accepted: 08/10/2014] [Indexed: 12/12/2022]
Abstract
Prosaposin (also known as SGP-1) is an intriguing multifunctional protein that plays roles both intracellularly, as a regulator of lysosomal enzyme function, and extracellularly, as a secreted factor with neuroprotective and glioprotective effects. Following secretion, prosaposin can undergo endocytosis via an interaction with the low-density lipoprotein-related receptor 1 (LRP1). The ability of secreted prosaposin to promote protective effects in the nervous system is known to involve activation of G proteins, and the orphan G protein-coupled receptors GPR37 and GPR37L1 have recently been shown to mediate signaling induced by both prosaposin and a fragment of prosaposin known as prosaptide. In this review, we describe recent advances in our understanding of prosaposin, its receptors and their importance in the nervous system.
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Affiliation(s)
- Rebecca C Meyer
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Michelle M Giddens
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Brilee M Coleman
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, United States
| | - Randy A Hall
- Department of Pharmacology, Emory University School of Medicine, Atlanta, GA 30322, United States.
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22
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Jain A, Migdalska- A, Jain A. Endothelin-1-Induced Endoplasmic Reticulum Stress in Parkinson's Disease. ACTA ACUST UNITED AC 2014. [DOI: 10.5567/pharmacologia.2014.84.90] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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GPR37 and GPR37L1 are receptors for the neuroprotective and glioprotective factors prosaptide and prosaposin. Proc Natl Acad Sci U S A 2013; 110:9529-34. [PMID: 23690594 DOI: 10.1073/pnas.1219004110] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
GPR37 (also known as Pael-R) and GPR37L1 are orphan G protein-coupled receptors that are almost exclusively expressed in the nervous system. We screened these receptors for potential activation by various orphan neuropeptides, and these screens yielded a single positive hit: prosaptide, which promoted the endocytosis of GPR37 and GPR37L1, bound to both receptors and activated signaling in a GPR37- and GPR37L1-dependent manner. Prosaptide stimulation of cells transfected with GPR37 or GPR37L1 induced the phosphorylation of ERK in a pertussis toxin-sensitive manner, stimulated (35)S-GTPγS binding, and promoted the inhibition of forskolin-stimulated cAMP production. Because prosaptide is the active fragment of the secreted neuroprotective and glioprotective factor prosaposin (also known as sulfated glycoprotein-1), we purified full-length prosaposin and found that it also stimulated GPR37 and GPR37L1 signaling. Moreover, both prosaptide and prosaposin were found to protect primary astrocytes against oxidative stress, with these protective effects being attenuated by siRNA-mediated knockdown of endogenous astrocytic GPR37 or GPR37L1. These data reveal that GPR37 and GPR37L1 are receptors for the neuroprotective and glioprotective factors prosaptide and prosaposin.
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Gandía J, Fernández-Dueñas V, Morató X, Caltabiano G, González-Muñiz R, Pardo L, Stagljar I, Ciruela F. The Parkinson's disease-associated GPR37 receptor-mediated cytotoxicity is controlled by its intracellular cysteine-rich domain. J Neurochem 2013; 125:362-72. [PMID: 23398388 DOI: 10.1111/jnc.12196] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 02/06/2013] [Accepted: 02/06/2013] [Indexed: 12/13/2022]
Abstract
GPR37, also known as parkin-associated endothelin-like receptor (Pael-R), is an orphan G protein-coupled receptor (GPCR) that aggregates intracellularly in a juvenile form of Parkinson's disease. However, little is known about the structure or function of this receptor. Here, in order to better understand the functioning of this receptor, we focused on the GPR37 C-terminal tail, in particular on a cystein-enriched region. Thus, we aimed to reveal the role of these residues on receptor plasma membrane expression and function, and also whether the presence of this cysteine-rich domain is linked to the previously described receptor-mediated cytotoxicity. Interestingly, while the deletion of six cysteine residues within this region did not affect receptor internalization it promoted GPR37 plasma membrane expression and signaling. Furthermore, the removal of the C-terminal cysteine-rich domain protected against GPR37-mediated apoptosis and cell death. Overall, we identified a GPR37 domain, namely the C-terminal tail cysteine-rich domain, which played a critical role in receptor cell surface expression, function and GPR37-mediated cytotoxicity. These results might contribute to better comprehend the pathophysiology (i.e. in Parkinson's disease) of this rather unknown member of the GPCR family.
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Affiliation(s)
- Jorge Gandía
- Unitat de Farmacologia, Departament de Patologia i Terapèutica Experimental, Facultat de Medicina, IDIBELL, Universitat de Barcelona, Barcelona, Spain
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Dusonchet J, Bensadoun JC, Schneider BL, Aebischer P. Targeted overexpression of the parkin substrate Pael-R in the nigrostriatal system of adult rats to model Parkinson's disease. Neurobiol Dis 2009; 35:32-41. [DOI: 10.1016/j.nbd.2009.03.013] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 03/03/2009] [Accepted: 03/25/2009] [Indexed: 10/20/2022] Open
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Imai Y, Inoue H, Kataoka A, Hua-Qin W, Masuda M, Ikeda T, Tsukita K, Soda M, Kodama T, Fuwa T, Honda Y, Kaneko S, Matsumoto S, Wakamatsu K, Ito S, Miura M, Aosaki T, Itohara S, Takahashi R. Pael receptor is involved in dopamine metabolism in the nigrostriatal system. Neurosci Res 2007; 59:413-25. [PMID: 17889953 DOI: 10.1016/j.neures.2007.08.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2007] [Revised: 08/03/2007] [Accepted: 08/10/2007] [Indexed: 02/07/2023]
Abstract
Pael receptor (Pael-R) has been identified as one of the substrates of Parkin, a ubiquitin ligase responsible for autosomal recessive juvenile Parkinsonism (AR-JP). When Parkin is inactivated, unfolded Pael-R accumulates in the endoplasmic reticulum and results in neuronal death by unfolded protein stress, suggesting that Pael-R has an important role in the pathogenesis of AR-JP. Here we report the analyses on Pael-R-deficient (KO) and Pael-R-transgenic (Tg) mice. The striatal dopamine (DA) level of Pael-R KO mice was only 60% of that in normal mice, while in Pael-R Tg mice, striatal 3,4-dihydroxyphenylacetic acid (DOPAC) as well as vesicular DA content increased. Moreover, the nigrostriatal dopaminergic neurons of Pael-R Tg mice are more vulnerable to Parkinson's disease-related neurotoxins while those of Pael-R KO mice are less. These results strongly suggest that the Pael-R signal regulates the amount of DA in the dopaminergic neurons and that excessive Pael-R expression renders dopaminergic neurons susceptible to chronic DA toxicity.
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Affiliation(s)
- Yuzuru Imai
- Laboratory for Motor System Neurodegeneration, RIKEN Brain Science Institute (BSI), Saitama, Japan.
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Takahashi R. [Neurodegeneration caused by ER stress?--the pathogenetic mechanisms underlying AR-JP]. Nihon Yakurigaku Zasshi 2005; 124:375-82. [PMID: 15572841 DOI: 10.1254/fpj.124.375] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Mutations of the Parkin gene are responsible for autosomal recessive juvenile parkinsonism (AR-JP), the most common cause of early-onset familial Parkinson's disease. Parkin functions as an E3 ubiquitin ligase, thereby promoting ubiquitination and subsequent proteosomal degradation of its substrate(s). AR-JP is, therefore, thought to be caused by accumulation of an unknown toxic protein(s), which would normally be degraded by a molecular machinery involving Parkin. To date, ten different proteins are reported to be substrates of Parkin. Among these, a G protein-coupled orphan receptor called the Pael receptor (Pael-R), which is highly expressed in dopaminergic neurons, attracts particular attention. When over-expressed in cells, the Pael-R protein became improperly folded and insoluble. Excessive accumulation of insoluble Pael-R led to endoplasmic reticulum (ER) stress-induced cell death. Parkin was observed to ubiquitinate the misfolded Pael-R protein, thereby promoting its degradation and suppressing misfolded Pael-R-induced cell death. Moreover, selective dopaminergic neurodegeneration was observed when human Pael-R was ectopically expressed in Drosophila brain, further supporting the idea that Pael-R accumulation plays a major role in AR-JP. In contrast, neither dopaminergic neurodegeneration nor accumulation of any known Parkin substrates was detected in Parkin knockout mice. The role of Pael-R in AR-JP will be discussed based on recent data.
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Affiliation(s)
- Ryosuke Takahashi
- Laboratory of Motor System Neurodegeneration, RIKEN Brain Science Institute, Saitama 351-0198, Japan
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29
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Abstract
Autosomal-recessive juvenile parkinsonism (AR-JP) is caused by mutations in the parkin gene. Parkin protein is characterized by a ubiquitin-like domain at its NH(2) terminus and by two RING finger motifs and one IBR (in between RING finger) motif at its COOH-terminus (RING-IBR-RING). We showed that the parkin protein is an E3 ubiquitin ligase, which binds to ubiquitin-conjugating enzymes (E2s) through its RING-IBR-RING motif. The pathogenesis of AR-JP, therefore, was hypothesized to be accumulation of unidentified neurotoxic protein (a substrate of parkin). On the basis of this hypothesis, the substrate of parkin was sought using a yeast two-hybrid system. A putative G protein-coupled transmembrane polypeptide, named Pael (parkin-associated endothelin receptor-like) receptor, was identified as a parkin binding protein. When overexpressed in cells, this receptor tends to become unfolded, insoluble, and ubiquitinated. The insoluble Pael receptor leads to endoplasmic reticulum (ER) stress-induced cell death. Parkin specifically ubiquitinates this receptor in the presence of ER-resident E2s and promotes the degradation of unfolded Pael receptor, resulting in suppression of the cell death induced by the accumulation of unfolded Pael receptor in the ER. Moreover, the insoluble form of Pael receptor accumulates in the brain of AR-JP patients. This protein is highly expressed in the dopaminergic neurons in the substantia nigra, which is specifically affected in Parkinson's disease; although it is also widely expressed in oligodendroglias in the fiber tract. In conclusion, we showed that the accumulation of unfolded Pael receptor (a substrate of parkin) may cause selective death of dopaminergic neurons in AR-JP.
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Affiliation(s)
- Ryosuke Takahashi
- Laboratory for Motor System Neurodegeneration, RIKEN Brain Science Institute, Saitama 351-0198, Japan.
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Imai Y, Soda M, Inoue H, Hattori N, Mizuno Y, Takahashi R. An unfolded putative transmembrane polypeptide, which can lead to endoplasmic reticulum stress, is a substrate of Parkin. Cell 2001; 105:891-902. [PMID: 11439185 DOI: 10.1016/s0092-8674(01)00407-x] [Citation(s) in RCA: 801] [Impact Index Per Article: 34.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
A putative G protein-coupled transmembrane polypeptide, named Pael receptor, was identified as an interacting protein with Parkin, a gene product responsible for autosomal recessive juvenile Parkinsonism (AR-JP). When overexpressed in cells, this receptor tends to become unfolded, insoluble, and ubiquitinated in vivo. The insoluble Pael receptor leads to unfolded protein-induced cell death. Parkin specifically ubiquitinates this receptor in the presence of ubiquitin-conjugating enzymes resident in the endoplasmic reticulum and promotes the degradation of insoluble Pael receptor, resulting in suppression of the cell death induced by Pael receptor overexpression. Moreover, the insoluble form of Pael receptor accumulates in the brains of AR-JP patients. Here, we show that the unfolded Pael receptor is a substrate of Parkin, the accumulation of which may cause selective neuronal death in AR-JP.
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Affiliation(s)
- Y Imai
- Laboratory for Motor System Neurodegeneration, RIKEN Brain Science Institute, Saitama 351-0198, Japan
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Leng N, Gu G, Simerly RB, Spindel ER. Molecular cloning and characterization of two putative G protein-coupled receptors which are highly expressed in the central nervous system. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 1999; 69:73-83. [PMID: 10350639 DOI: 10.1016/s0169-328x(99)00092-3] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have cloned from a rat hypothalamic cDNA library two closely related G protein-coupled receptors (GPCRs) which we have designated GPCR/CNS1 and GPCR/CNS2. The peptide sequences of these two G protein-coupled receptors shared 42% identity with each other and were next most closely related to the endothelin receptors and the bombesin-like peptide receptors (approximately 25% identity). Northern blot analysis showed that both GPCR/CNS1 and GPCR/CNS2 were very highly expressed in rat brain. In situ hybridization of rat brain demonstrated broad distribution of both receptors throughout the central nervous system. GPCR/CNS1 appeared to be expressed primarily in glial cells of the fiber tracts, while GPCR/CNS2 was expressed primarily in cells of the gray matter. The different distribution patterns of these two receptors in rat brain suggests distinct functional roles for each receptor in the central nervous system. Expression of these two receptors in Xenopus oocytes showed no response to any known endothelin and bombesin-like peptides. Therefore, the endogenous ligands and physiological significance of GPCR/CNS1 and GPCR/CNS2 remain to be elucidated, but may be related to the endothelins or bombesins. The very abundant expression in brain by these two receptors, however, suggests that they play important roles in the central nervous system.
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MESH Headings
- Animals
- Blotting, Northern
- Brain Chemistry/genetics
- Cloning, Molecular
- DNA, Complementary
- GTP-Binding Proteins/genetics
- In Situ Hybridization
- Molecular Sequence Data
- Nerve Tissue Proteins/genetics
- Oocytes/physiology
- Peptidylprolyl Isomerase/genetics
- RNA, Messenger/analysis
- RNA, Ribosomal, 18S/analysis
- RNA, Ribosomal, 28S/analysis
- Rats
- Receptor, Endothelin B
- Receptors, Bombesin/genetics
- Receptors, Cell Surface/genetics
- Receptors, Endothelin/genetics
- Receptors, G-Protein-Coupled
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Xenopus laevis
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Affiliation(s)
- N Leng
- Division of Neuroscience Oregon Regional Primate Research Center, Beaverton, OR 97006, USA
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