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Wang C, Chen W, Shen J. CXCR7 Targeting and Its Major Disease Relevance. Front Pharmacol 2018; 9:641. [PMID: 29977203 PMCID: PMC6021539 DOI: 10.3389/fphar.2018.00641] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 05/29/2018] [Indexed: 12/25/2022] Open
Abstract
Chemokine receptors are the target of small peptide chemokines. They play various important roles in physiological and pathological processes. CXCR7, later renamed ACKR3, is a non-classical seven transmembrane-spanning receptor whose function as a signaling or non-signaling scavenger/decoy receptor is currently under debate. Even for cell signaling mechanisms, there has been inconsistency on whether CXCR7 couples to G-proteins or β-arrestins. Several reasons may contribute to this uncertainty or controversy. In one hand, it has been neglected that CXCR7 has more than five natural ligands and unfortunately, most of the prior research only studied SDF-1 (CXCL12) and/or I-TAC (CXCL11); on the other hand, there are mounting evidence supporting ligand and tissue bias for receptor signaling, but limited such information is available for CXCR7. In this review we focus on summarizing the endogenous and exogenous ligands of CXCR7, the main diseases related to CXCR7 and the biased signaling events happening on CXCR7. These three aspects of CXCR7 pharmacologic properties may explain why the contradicting opinions of whether CXCR7 is a signaling or non-signaling receptor exist. Further, potential new direction and perspective for the study of CXCR7 biology and pharmacology are highlighted.
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Affiliation(s)
- Chuan Wang
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, United States
| | - Weilin Chen
- Department of Immunology, Shenzhen University School of Medicine, Shenzhen, China
| | - Jianzhong Shen
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, United States
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Sánchez-Martín L, Sánchez-Mateos P, Cabañas C. CXCR7 impact on CXCL12 biology and disease. Trends Mol Med 2012; 19:12-22. [PMID: 23153575 DOI: 10.1016/j.molmed.2012.10.004] [Citation(s) in RCA: 164] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Revised: 09/20/2012] [Accepted: 10/11/2012] [Indexed: 12/14/2022]
Abstract
It is known that the chemokine receptor CXCR7 (RDC1) can be engaged by both chemokines CXCL12 (SDF-1) and CXCL11 (I-TAC), but the exact expression pattern and function of CXCR7 is controversial. CXCR7 expression seems to be enhanced during pathological inflammation and tumor development, and emerging data suggest this receptor is an attractive therapeutic target for autoimmune diseases and cancer. CXCR7/CXCR4 heterodimerization, β-arrestin-mediated signaling, and modulation of CXCL12 responsiveness by CXCR7 suggest that the monogamous CXCR4/CXCL12 signaling axis is an oversimplified model that needs to be revisited. Consequently, research into CXCR7 biology is of great interest and further studies are warranted. This review summarizes recent findings about the CXCR7 receptor and analyses its impact on understanding the roles of CXCL12 biology in health and disease.
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Affiliation(s)
- Lorena Sánchez-Martín
- Departamento de Biología Celular e Inmunología, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid 28049, Spain.
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Abstract
Poliomyelitis is an acute paralytic disease caused by three poliovirus (PV) serotypes. Less than 1% of PV infections result in acute flaccid paralysis. The disease was controlled using the formalin-inactivated Salk polio vaccine (IPV) and the Sabin oral polio vaccine (OPV). Global poliomyelitis eradication was proposed in 1988 by the World Health Organization to its member states. The strategic plan established the activities required for polio eradication, certification for regions, OPV cessation phase and post-OPV phase. OPV is the vaccine of choice for the poliomyelitis eradication program because it induces both a systemic and mucosal immune response. The major risks of OPV vaccination are the appearance of Vaccine-Associated Paralytic Poliomyelitis cases (VAPP) and the emergence of Vaccine Derived Polioviruses strains. The supplementary immunization with monovalent strains of OPV type 1 or type 3 or with a new bivalent oral polio vaccine bOPV (containing type 1 and type 3 PV) has been introduced in those regions where the virus has been difficult to control. Most countries have switched the schedule of vaccination by using IPV instead of OPV because it poses no risk of vaccine-related disease. Until 2008, poliomyelitis was controlled in Romania, an Eastern European country, predominantly using OPV. The alternative vaccination schedule (IPV/OPV) was implemented starting in September 2008, while beginning in 2009, the vaccination was IPV only. The risk of VAPP will disappear worldwide with the cessation of use of OPV. The immunization for polio must be maintained for at least 5 to 10 years using IPV.
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Affiliation(s)
- Anda Baicus
- Anda Baicus, National Institute of Research and Development for Microbiology and Immunology Cantacuzino, University of Medicine and Pharmacy "Carol Davila", 050096 Bucharest, Romania
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4
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Differential expression of RDC1/CXCR7 in the human placenta. J Clin Immunol 2008; 29:379-86. [PMID: 18956235 DOI: 10.1007/s10875-008-9258-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2008] [Accepted: 10/07/2008] [Indexed: 10/21/2022]
Abstract
INTRODUCTION Chemokine receptor expression by human trophoblast and other placental cells have important implications for understanding the regulation of placental growth, development, and their role in maternofetal HIV transmission. CXCR7, now a deorphanized G protein coupled receptor that has been recently shown to bind to the ligands ITAC and CXCL12 has been proposed to act as a co-receptor for HIV-1, HIV-2, and SIV strains. The differential expression of CXCR7 in the human placenta is not yet reported. METHODS The expression of CXCR7 was studied in 45 different human placental tissues, of which 20 were from early placental tissues (8-10 week old) obtained from medically terminated pregnancies and 25 were placenta from normal term deliveries. RESULTS Immunohistochemistry and RT-PCR analysis revealed a greater expression of CXCR7 in term human placenta as compared to the early stage. This was further confirmed by real-time PCR. CONCLUSION Our study reveals, for the first time, the differential expression of CXCR7 in early (8-10 weeks) and term human placenta. The precise role of CXCR7 in the human placenta needs to be determined. HIV vertical transmission is reported to occur mainly during the end stages of pregnancy. Our finding of increased CXCR7 expression in the term human placenta therefore warrants future studies to assess its role in the vertical transmission of HIV-1.
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Abstract
CXCR7, formerly called RDC1 is a recently deorphanized G-protein coupled receptor which binds with high affinity the inflammatory and homing chemokines CXCL11/ITAC and CXCL12/SDF-1. Despite its phylogenetic relation and ligand binding properties CXCR7 does not mediate typical chemokine receptor responses such as leukocyte trafficking. Recent findings in zebrafish indicate that a critical activity of the receptor is scavenging of CXCL12 thereby generating guidance cues for CXCR4-dependent migration. The observations do not exclude the possibility that the receptor is capable of inducing signal transduction which is suggestive from studies of tumor growth and survival. The pronounced expression in central and peripheral nervous tissue and the absence of a brain phenotype in CXCR7(-/-) mice suggest a subtle activity of the receptor.
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Balabanian K, Lagane B, Infantino S, Chow KYC, Harriague J, Moepps B, Arenzana-Seisdedos F, Thelen M, Bachelerie F. The chemokine SDF-1/CXCL12 binds to and signals through the orphan receptor RDC1 in T lymphocytes. J Biol Chem 2005; 280:35760-6. [PMID: 16107333 DOI: 10.1074/jbc.m508234200] [Citation(s) in RCA: 798] [Impact Index Per Article: 42.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Combined phylogenetic and chromosomal location studies suggest that the orphan receptor RDC1 is related to CXC chemokine receptors. RDC1 provides a co-receptor function for a restricted number of human immunodeficiency virus (HIV) isolates, in particular for the CXCR4-using HIV-2 ROD strain. Here we show that CXCL12, the only known natural ligand for CXCR4, binds to and signals through RDC1. We demonstrate that RDC1 is expressed in T lymphocytes and that CXCL12-promoted chemotaxis is inhibited by an anti-RDC1 monoclonal antibody. Concomitant blockade of RDC1 and CXCR4 produced additive inhibitory effects in CXCL12-induced T cell migration. Furthermore, we provide evidence that interaction of CXCL12 with RDC1 is specific, saturable, and of high affinity (apparent KD approximately 0.4 nM). In CXCR4-negative cells expressing RDC1, CXCL12 promotes internalization of the receptor and chemotactic signals through RDC1. Collectively, our data indicate that RDC1, which we propose to rename as CXCR7, is a receptor for CXCL12.
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Affiliation(s)
- Karl Balabanian
- Unité d'Immunologie Virale, Institut Pasteur, 75015 Paris, France
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7
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Raggo C, Ruhl R, McAllister S, Koon H, Dezube BJ, Früh K, Moses AV. Novel cellular genes essential for transformation of endothelial cells by Kaposi's sarcoma-associated herpesvirus. Cancer Res 2005; 65:5084-95. [PMID: 15958552 DOI: 10.1158/0008-5472.can-04-2822] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Kaposi's sarcoma-associated herpesvirus (KSHV) is involved in the development of lymphoproliferative diseases and Kaposi's sarcoma. The oncogenicity of this virus is reflected in vitro by its ability to transform B cells and endothelial cells. Infection of dermal microvascular endothelial cells (DMVEC) transforms the cells from a cobblestone-like monolayer to foci-forming spindle cells. This transformation is accompanied by dramatic changes in the cellular transcriptome. Known oncogenes, such as c-Kit, are among the KSHV-induced host genes. We previously showed that c-Kit is an essential cellular component of the KSHV-mediated transformation of DMVEC. Here, we test the hypothesis that the transformation process can be used to discover novel oncogenes. When expression of a panel of KSHV-induced cellular transcripts was inhibited with antisense oligomers, we observed inhibition of DMVEC proliferation and foci formation using antisense molecules to RDC1 and Neuritin. We further showed that transformation of KSHV-infected DMVEC was inhibited by small interfering RNA directed at RDC1 or Neuritin. Ectopic expression of Neuritin in NIH 3T3 cells resulted in changes in cell morphology and anchorage-independent growth, whereas RDC1 ectopic expression significantly increased cell proliferation. In addition, both RDC1- and Neuritin-expressing cells formed tumors in nude mice. RDC1 is an orphan G protein-coupled receptor, whereas Neuritin is a growth-promoting protein known to mediate neurite outgrowth. Neither gene has been previously implicated in tumorigenesis. Our data suggest that KSHV-mediated transformation involves exploitation of the hitherto unrealized oncogenic properties of RDC1 and Neuritin.
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MESH Headings
- Adaptor Proteins, Signal Transducing
- Animals
- Cell Transformation, Viral/genetics
- DNA-Binding Proteins/biosynthesis
- DNA-Binding Proteins/genetics
- Endothelial Cells/cytology
- Endothelial Cells/virology
- GPI-Linked Proteins
- Gene Expression Profiling
- Herpesvirus 8, Human/genetics
- Herpesvirus 8, Human/physiology
- Humans
- LIM Domain Proteins
- Metalloproteins/biosynthesis
- Metalloproteins/genetics
- Mice
- Mice, Nude
- NIH 3T3 Cells
- Neuropeptides/biosynthesis
- Neuropeptides/genetics
- Oligonucleotide Array Sequence Analysis
- Oligonucleotides, Antisense/genetics
- Oncogenes/physiology
- Osteopontin
- Proto-Oncogene Proteins
- RNA, Small Interfering/genetics
- Receptors, CXCR
- Receptors, Chemokine/biosynthesis
- Receptors, Chemokine/genetics
- Receptors, G-Protein-Coupled/biosynthesis
- Receptors, G-Protein-Coupled/genetics
- Sarcoma, Kaposi/genetics
- Sarcoma, Kaposi/virology
- Sialoglycoproteins/biosynthesis
- Sialoglycoproteins/genetics
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Affiliation(s)
- Camilo Raggo
- Vaccine and Gene Therapy Institute, Oregon Health and Science University, Beaverton, Oregon, USA
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8
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Abstract
The effects of vasoactive intestinal peptide (VIP) on the proliferation of central nervous system (CNS) and cancer cells were investigated. VIP has important actions during CNS development. During neurogenesis, VIP stimulates the proliferation and differentiation of brain neurons. Addition of VIP to embryonic mouse spinal cord cultures increases neuronal survival and activity dependent neurotrophic factor (ADNF) secretion from astroglial cells. VIP is an integrative regulator of brain growth and development during neurogenesis and embryogenesis. Also, VIP causes increased proliferation of human breast and lung cancer cells in vitro. VIP binds with high affinity to cancer cells, elevates the cAMP and increases gene expression of c-fos, c-jun, c-myc and vascular endothelial cell growth factor. The effects of VIP on cancer cells are reversed by VIPhybrid, a synthetic VPAC(1) receptor antagonist. VIPhyb inhibits the basal growth of lung cancer cells in vitro and tumors in vivo and potentiates the ability of chemotherapeutic drugs to kill cancer cells. Due to the high density of VPAC(1) receptors in cancer cells, VIP has been radiolabeled with 123I, 18F and 99mTc to image tumors. It remains to be determined if radiolabeled VIP analogs will be useful agents for early detection of cancer in patients.
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Affiliation(s)
- Terry W Moody
- NCI Office of the Director, Center for Cancer Research, National Cancer Institute, Bldg 31, Rm 3A34, 31 Center Dr, Bethesda, MD, USA.
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9
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Molecular Pharmacology and Structure-Function Analysis of PACAP/Vip Receptors. PITUITARY ADENYLATE CYCLASE-ACTIVATING POLYPEPTIDE 2003. [DOI: 10.1007/978-1-4615-0243-2_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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10
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Laburthe M, Couvineau A. Molecular pharmacology and structure of VPAC Receptors for VIP and PACAP. REGULATORY PEPTIDES 2002; 108:165-73. [PMID: 12220741 DOI: 10.1016/s0167-0115(02)00099-x] [Citation(s) in RCA: 122] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
VIP and PACAP are two prominent neuropeptides which share two common G protein-coupled receptors VPAC1 and VPAC2 while PACAP has an additional specific receptor PAC1. This paper reviews the present knowledge regarding three aspects of VPAC receptors including: (i). receptor specificity towards natural VIP-related peptides and pharmacology of synthetic agonists or antagonists; (ii). receptor signaling; (iii). molecular basis of ligand-receptor interaction as determined by site-directed mutagenesis, construction of receptor chimeras and structural modeling.
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MESH Headings
- Amino Acid Sequence
- Animals
- Humans
- Ligands
- Models, Molecular
- Neuropeptides/physiology
- Pituitary Adenylate Cyclase-Activating Polypeptide
- Protein Conformation
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide
- Receptors, Pituitary Adenylate Cyclase-Activating Polypeptide, Type I
- Receptors, Pituitary Hormone/physiology
- Receptors, Vasoactive Intestinal Peptide/chemistry
- Receptors, Vasoactive Intestinal Peptide/physiology
- Receptors, Vasoactive Intestinal Peptide, Type II
- Receptors, Vasoactive Intestinal Polypeptide, Type I
- Substrate Specificity
- Vasoactive Intestinal Peptide/chemistry
- Vasoactive Intestinal Peptide/metabolism
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Affiliation(s)
- M Laburthe
- Neuroendocrinology and Cell Biology, INSERM U41O, Faculté de Médecine Xavier Bichat, 75018, Paris, France.
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11
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Yallampalli C, Chauhan M, Thota CS, Kondapaka S, Wimalawansa SJ. Calcitonin gene-related peptide in pregnancy and its emerging receptor heterogeneity. Trends Endocrinol Metab 2002; 13:263-9. [PMID: 12128288 DOI: 10.1016/s1043-2760(02)00563-5] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Calcitonin gene-related peptide (CGRP) is the most potent vasodilator, and there is a growing body of evidence that this peptide might have multiple other functions. During pregnancy, circulating CGRP levels in rats increase up to the time of delivery, followed by a sharp decline at term and postpartum. In addition, the sensitivity of various vascular beds to CGRP in rats appears to increase with advancing pregnancy. This increased sensitivity might be involved in regulating uteroplacental blood flow, in addition to other vascular adaptations that occur during normal pregnancy. Furthermore, the uterine relaxation response to CGRP is elevated during pregnancy and decreased at term. Sex steroid hormones, estrogens and progesterone, regulate CGRP synthesis and its effects on both myometrial and uterine vascular tissues. These changes in smooth muscle relaxation sensitivity to CGRP appear to be a consequence of changes in CGRP-receptor levels in these tissues. There appear to be two receptors for CGRP: the CGRP-A receptor, a well-characterized receptor consisting of calcitonin receptor-like receptor and receptor activity modifying protein 1, and the CGRP-B receptor. The CGRP system might play a role in the maintenance of normal pregnancy, and a defect in this system might lead to complications.
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12
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Shimizu N, Soda Y, Kanbe K, Liu HY, Mukai R, Kitamura T, Hoshino H. A putative G protein-coupled receptor, RDC1, is a novel coreceptor for human and simian immunodeficiency viruses. J Virol 2000; 74:619-26. [PMID: 10623723 PMCID: PMC111581 DOI: 10.1128/jvi.74.2.619-626.2000] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
More than 10 G protein-coupled receptors (GPCRs) have been shown to act as coreceptors for infection of human immunodeficiency virus type 1 (HIV-1), HIV-2, and simian immunodeficiency virus (SIV). We have isolated HIV-1 variants infectious to primary brain-derived CD4-positive cells (BT-3 and BT-20/N) and U87/CD4 glioma cells that are resistant to T-cell line-tropic (T-tropic), macrophage-tropic (M-tropic), and T- and M-tropic (dualtropic) (X4, R5, and R5X4) HIV-1 strains. These primary brain-derived cells were also highly susceptible to HIV-2(ROD), HIV-2(SBL6669), and SIV(mndGB-1). A factor or coreceptor that determines the susceptibility of these brain-derived cells to these HIV and SIV strains has not been fully identified. To identify this coreceptor, we examined amino acid sequences of all known HIV and SIV coreceptors and noticed that tyrosine residues are well conserved in their extracellular amino-terminal domains. By this criterion, we selected 18 GPCRs as candidates of coreceptors for HIV and SIV strains infectious to these brain-derived cells. mRNA expression of an orphan GPCR, RDC1, was detected in the brain-derived cells, the C8166 T-cell line, and peripheral blood lymphocytes, all of which are susceptible to HIV-1 variants, but not in macrophages, which are resistant to them. When a CD4-expressing cell line, NP-2/CD4, which shows strict resistance to infection not only with HIV-1 but also with HIV-2 or SIV, was transduced with the RDC1 gene, the cells became highly susceptible to HIV-2 and SIV(mnd) strains but to neither M- nor T-tropic HIV-1 strains. The cells also acquired a low susceptibility to the HIV-1 variants. These findings indicate that RDC1 is a novel coreceptor for several HIV-1, HIV-2, and SIV strains which infect brain-derived cells.
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MESH Headings
- Animals
- CD4 Antigens/metabolism
- Cell Line
- Gene Expression
- HIV-1/metabolism
- HIV-1/physiology
- HIV-2/metabolism
- HIV-2/physiology
- Humans
- Phylogeny
- Receptors, CXCR
- Receptors, Cell Surface/classification
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, Chemokine
- Receptors, G-Protein-Coupled
- Receptors, HIV/classification
- Receptors, HIV/genetics
- Receptors, HIV/metabolism
- Receptors, Virus/classification
- Receptors, Virus/genetics
- Receptors, Virus/metabolism
- Simian Immunodeficiency Virus/metabolism
- Simian Immunodeficiency Virus/physiology
- Tumor Cells, Cultured
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Affiliation(s)
- N Shimizu
- Department of Virology and Preventive Medicine, Gunma University School of Medicine, Maebashi, Gunma 371-8511, Japan
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13
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Wilson S, Bergsma DJ, Chambers JK, Muir AI, Fantom KG, Ellis C, Murdock PR, Herrity NC, Stadel JM. Orphan G-protein-coupled receptors: the next generation of drug targets? Br J Pharmacol 1998; 125:1387-92. [PMID: 9884064 PMCID: PMC1565744 DOI: 10.1038/sj.bjp.0702238] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The pharmaceutical industry has readily embraced genomics to provide it with new targets for drug discovery. Large scale DNA sequencing has allowed the identification of a plethora of DNA sequences distantly related to known G protein-coupled receptors (GPCRs), a superfamily of receptors that have a proven history of being excellent therapeutic targets. In most cases the extent of sequence homology is insufficient to assign these 'orphan' receptors to a particular receptor subfamily. Consequently, reverse molecular pharmacological and functional genomic strategies are being employed to identify the activating ligands of the cloned receptors. Briefly, the reverse molecular pharmacological methodology includes cloning and expression of orphan GPCRs in mammalian cells and screening these cells for a functional response to cognate or surrogate agonists present in biological extract preparations, peptide libraries, and complex compound collections. The functional genomics approach involves the use of 'humanized yeast cells, where the yeast GPCR transduction system is engineered to permit functional expression and coupling of human GPCRs to the endogenous signalling machinery. Both systems provide an excellent platform for identifying novel receptor ligands. Once activating ligands are identified they can be used as pharmacological tools to explore receptor function and relationship to disease.
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Affiliation(s)
- S Wilson
- SmithKline Beecham Pharmaceuticals, Harlow, Essex
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14
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Kennedy SP, Sun D, Oleynek JJ, Hoth CF, Kong J, Hill RJ. Expression of the rat adrenomedullin receptor or a putative human adrenomedullin receptor does not correlate with adrenomedullin binding or functional response. Biochem Biophys Res Commun 1998; 244:832-7. [PMID: 9535752 DOI: 10.1006/bbrc.1998.8349] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There has been considerable difficulty in defining distinct adrenomedullin (AM) binding sites and function in vivo. However, a rat adrenomedullin receptor (rAMR) and a putative human adrenomedullin receptor (hAMR) have recently been reported. We attempted to confirm and extend the pharmacological characterization of these cloned receptors. COS-7 cells transfected with rAMR or epitope tagged rAMR display abundant rAMR mRNA expression and cell-surface receptor localization. Specific 125I-AM binding is detected in transfected cells; however, similar levels of binding are also detected in cells transfected with vector DNA alone. This AM binding site fails to mediate any changes in cAMP in response to AM. In contrast, Swiss 3T3 cells, expressing specific endogenous AM receptors, display AM binding and functional cAMP responses. Transfection studies performed with the putative hAMR yield similar results. These data suggest that the proposed rAMR and hAMR do not represent authentic adrenomedullin receptors.
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Affiliation(s)
- S P Kennedy
- Department of Molecular Sciences, Pfizer Inc., Groton, Connecticut 06340, USA.
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15
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Cell Surface Receptors and the G Protein-Coupled Receptor Superfamily. G PROTEIN-COUPLED RECEPTORS 1995. [DOI: 10.1007/978-3-662-21930-0_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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16
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Gagnon AW, Aiyar N, Elshourbagy NA. Molecular cloning and functional characterization of a human liver vasoactive intestinal peptide receptor. Cell Signal 1994; 6:321-33. [PMID: 7917790 DOI: 10.1016/0898-6568(94)90037-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We have isolated a cDNA from a human liver library which is 2349 base pairs in length and encodes a near-full length seven transmembrane receptor (432 amino acids), 85% homologous to the amino acid sequence for the rat vasoactive intestinal peptide (VIP) receptor. Northern blot analysis identifies a major species at 3.3 kb in lung, and to a lesser extent in brain, heart and liver. In order to confirm the identity of this human clone, double-stranded oligonucleotides encoding the signal peptide of the rat VIP receptor were constructed by polymerase chain reaction and attached to the 5' end of the human clone. COS cells transiently transfected with this human VIP receptor chimera, express a single binding site for 125I-VIP with a Kd of 9.2 +/- 2 nM. Related peptides displace 125I-VIP with a relative potency of VIP = PACAP > helodermin >> PHM > secretin, which is similar to the binding profile seen in human tissues. This human chimeric receptor is functionally coupled to the stimulation of adenylyl cyclase in transfected COS cells, as evidenced by a dose-dependent increase in intracellular cAMP accumulation. These studies indicate that this cDNA encodes a human liver VIP receptor which is functionally coupled to the activation of adenylyl cyclase.
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Affiliation(s)
- A W Gagnon
- Department of Molecular Genetics, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406
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17
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Eva C, Sprengel R. A novel putative G protein-coupled receptor highly expressed in lung and testis. DNA Cell Biol 1993; 12:393-9. [PMID: 8390839 DOI: 10.1089/dna.1993.12.393] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
A putative novel G protein-coupled receptor was isolated using the polymerase chain reaction (PCR) and conventional library screening. Degenerate primers corresponding to the thyroid and the sixth transmembrane regions that are conserved among the G protein-coupled receptors were used to amplify selectively gene fragments of new members of this receptor family from a neuroblastoma-glioma cell line cDNA. One of the PCR amplification products that by sequence analysis appeared to contain a partial fragment of a novel G protein-coupled receptor gene was used as a probe to screen a rat forebrain cDNA library to isolate a full-length clone. Sequence comparison indicates that the new gene belongs to the G protein-coupled receptor family and displays the highest structural similarity with the dog RDC1 orphan receptor and several hormone peptide receptors. The mRNA for this putative receptor is not expressed in any specific region of the brain but seems to be localized in a restricted number of peripheral tissues, including lung, testes, and kidney. We suggest that the 4-24 cDNA clone encodes for a novel G protein-coupled receptor that may belong to hormone peptide receptor family.
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Affiliation(s)
- C Eva
- Istituto di Farmacologia e Terapia Sperimentale, School of Medicine, University of Torino, Italy
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18
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Fabre C, el Battari A, Karamanos Y, Couvineau A, Salomon R, Laburthe M, Marvaldi J, Pichon J, Luis J. Glycosylation of VIP receptors: a molecular basis for receptor heterogeneity. Peptides 1993; 14:483-9. [PMID: 8392717 DOI: 10.1016/0196-9781(93)90136-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Apparent molecular weights of VIP-binding proteins differ greatly according to species and to tissue. In this study, we used plasma membranes from various species (human, rat, pig) and tissues (melanoma, intestine, liver), which display major 125I-VIP-labeled components with molecular weights ranging from M(r) = 51,800 to 66,800. With the exception of porcine receptor, the various VIP receptors had similar apparent molecular weights after removal of their N-linked carbohydrates. In addition to differences in the amount of asparagine-linked glycans, our results also revealed differences in the composition of the oligosaccharide chains, which can also account for the heterogeneity in the molecular weights of the VIP receptor.
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Affiliation(s)
- C Fabre
- Institut de Chimie Biologique, CNRS URA 202, Université de Provence, Marseille, France
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19
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Abstract
Recently, the primary structures of 17 different receptors for neuropeptides and small peptide hormones have been elucidated by molecular cloning. All but one belong to the superfamily of G-protein coupled receptors which share a topography consisting of seven transmembrane domains. Comparison of primary structures shows that two classes of peptide receptors exist. One referred to as the 'neurokinin-type receptors', possesses many of the typical, conserved amino acid sequence motifs of the aminergic transmitter receptors (e.g. beta-adrenoceptor). The other, referred to the 'secretin-type receptors', displays unrelated and distinctly different sequence motifs which are conserved between the three presently known members of this class. These are the secretin, calcitonin and parathyroid hormone/parathyroid hormone-like polypeptide receptors. One may speculate that many other peptides with a core of biological activity in the N-terminal or middle region may have receptors of the secretin-type.
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Affiliation(s)
- J P Burbach
- Rudolf Magnus Institute, Department of Pharmacology, Utrecht University, Netherlands
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