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Duraisamy K, Kumar M, Nawabjan A, Lo EKK, Hui Lin M, Lefranc B, Bonnafé E, Treilhou M, El-Nezami H, Leprince J, Chow BKC. MRGPRB2/X2 and the analogous effects of its agonist and antagonist in DSS-induced colitis in mice. Biomed Pharmacother 2024; 174:116471. [PMID: 38547764 DOI: 10.1016/j.biopha.2024.116471] [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: 10/23/2023] [Revised: 03/08/2024] [Accepted: 03/18/2024] [Indexed: 05/01/2024] Open
Abstract
The mast cell receptor Mrgprb2, a mouse orthologue of human Mrgprx2, is known as an inflammatory receptor and its elevated expression is associated with various diseases such as ulcerative colitis. We aimed to elucidate the role of Mrgprb2/x2 and the effect of its ligands on a chemically induced murine colitis model. We showed that in Mrgprb2-/- mice, there is a differential regulation of cytokine releases in the blood plasma and severe colonic damages after DSS treatment. Unexpectedly, we demonstrated that known Mrgprb2/x2 agonists (peptide P17, P17 analogues and CST-14) and antagonist (GE1111) similarly increased the survival rate of WT mice subjected to 4% DSS-induced colitis, ameliorated the colonic damages of 2.5% DSS-induced colitis, restored major protein mRNA expression involved in colon integrity, reduced CD68+ and F4/80+ immune cell infiltration and restored cytokine levels. Collectively, our findings highlight the eminent role of Mrpgrb2/x2 in conferring a beneficial effect in the colitis model, and this significance is demonstrated by the heightened severity of colitis with altered cytokine releases and inflammatory immune cell infiltration observed in the Mrgprb2 knockout mice. Elevated expression of Mrgprb2 in WT colitis murine models may represent the organism's adaptive protective mechanism since Mrgprb2 knockout results in severe colitis. On the other hand, both agonist and antagonist of Mrgprb2 analogously mitigated the severity of colitis in DSS-induced colitis model by altering Mrgprb2 expression, immune cell infiltration and inflammatory cytokine releases.
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Affiliation(s)
- Karthi Duraisamy
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China; INSERM U1239 NorDiC, PRIMACEN, Université Rouen Normandie, Rouen, France
| | - Mukesh Kumar
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Abdullah Nawabjan
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Emily Kwun Kwan Lo
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Ming Hui Lin
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China
| | - Benjamin Lefranc
- INSERM U1239 NorDiC, PRIMACEN, Université Rouen Normandie, Rouen, France
| | - Elsa Bonnafé
- EA7417 BTSB, Université Fédérale Toulouse Midi-Pyrénées, INU Champollion, Albi, France
| | - Michel Treilhou
- EA7417 BTSB, Université Fédérale Toulouse Midi-Pyrénées, INU Champollion, Albi, France
| | - Hani El-Nezami
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China; Institute of Public Health and Clinical Nutrition, University of Eastern Finland, Kuopio, Finland
| | - Jérôme Leprince
- INSERM U1239 NorDiC, PRIMACEN, Université Rouen Normandie, Rouen, France.
| | - Billy K C Chow
- School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
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Bodin S, Previti S, Jestin E, Vimont D, Ait-Arsa I, Lamare F, Rémond E, Hindié E, Cavelier F, Morgat C. Design, Synthesis, and Biological Evaluation of the First Radio-Metalated Neurotensin Analogue Targeting Neurotensin Receptor 2. ACS OMEGA 2023; 8:6994-7004. [PMID: 36844603 PMCID: PMC9948202 DOI: 10.1021/acsomega.2c07814] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 01/30/2023] [Indexed: 05/28/2023]
Abstract
Neurotensin receptor 2 (NTS2) is a well-known mediator of central opioid-independent analgesia. Seminal studies have highlighted NTS2 overexpression in a variety of tumors including prostate cancer, pancreas adenocarcinoma, and breast cancer. Herein, we describe the first radiometalated neurotensin analogue targeting NTS2. JMV 7488 (DOTA-(βAla)2-Lys-Lys-Pro-(D)Trp-Ile-TMSAla-OH) was prepared using solid-phase peptide synthesis, then purified, radiolabeled with 68Ga and 111In, and investigated in vitro on HT-29 cells and MCF-7 cells, respectively, and in vivo on HT-29 xenografts. [68Ga]Ga-JMV 7488 and [111In]In-JMV 7488 were quite hydrophilic (logD7.4 = -3.1 ± 0.2 and -2.7 ± 0.2, respectively, p < 0.0001). Saturation binding studies showed good affinity toward NTS2 (K D = 38 ± 17 nM for [68Ga]Ga-JMV 7488 on HT-29 and 36 ± 10 nM on MCF-7 cells; K D = 36 ± 4 nM for [111In]In-JMV 7488 on HT-29 and 46 ± 1 nM on MCF-7 cells) and good selectivity (no NTS1 binding up to 500 nM). On cell-based evaluation, [68Ga]Ga-JMV 7488 and [111In]In-JMV 7488 showed high and fast NTS2-mediated internalization of 24 ± 5 and 25 ± 11% at 1 h for [111In]In-JMV 7488, respectively, along with low NTS2-membrane binding (<8%). Efflux was as high as 66 ± 9% at 45 min for [68Ga]Ga-JMV 7488 on HT-29 and increased for [111In]In-JMV 7488 up to 73 ± 16% on HT-29 and 78 ± 9% on MCF-7 cells at 2 h. Maximum intracellular calcium mobilization of JMV 7488 was 91 ± 11% to that of levocabastine, a known NTS2 agonist on HT-29 cells demonstrating the agonist behavior of JMV 7488. In nude mice bearing HT-29 xenograft, [68Ga]Ga-JMV 7488 showed a moderate but promising significant tumor uptake in biodistribution studies that competes well with other nonmetalated radiotracers targeting NTS2. Significant uptake was also depicted in lungs. Interestingly, mice prostate also demonstrated [68Ga]Ga-JMV 7488 uptake although the mechanism was not NTS2-mediated.
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Affiliation(s)
- Sacha Bodin
- Department
of Nuclear Medicine, University Hospital
of Bordeaux, 33076 Bordeaux, France
- University
of Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux F-33000, France
| | - Santo Previti
- Institut
des Biomolécules Max Mousseron, IBMM, UMR 5247, CNRS, Université
de Montpellier, ENSCM, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Emmanuelle Jestin
- Cyclotron
Réunion Océan Indien CYROI, 2 rue Maxime Rivière, 97490 Sainte Clotilde, France
| | - Delphine Vimont
- University
of Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux F-33000, France
| | - Imade Ait-Arsa
- Cyclotron
Réunion Océan Indien CYROI, 2 rue Maxime Rivière, 97490 Sainte Clotilde, France
| | - Frédéric Lamare
- Department
of Nuclear Medicine, University Hospital
of Bordeaux, 33076 Bordeaux, France
- University
of Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux F-33000, France
| | - Emmanuelle Rémond
- Institut
des Biomolécules Max Mousseron, IBMM, UMR 5247, CNRS, Université
de Montpellier, ENSCM, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Elif Hindié
- Department
of Nuclear Medicine, University Hospital
of Bordeaux, 33076 Bordeaux, France
- University
of Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux F-33000, France
- Institut
Universitaire de France, 1 rue Descartes, 75231 Paris, France
| | - Florine Cavelier
- Institut
des Biomolécules Max Mousseron, IBMM, UMR 5247, CNRS, Université
de Montpellier, ENSCM, 1919 route de Mende, 34293 Montpellier cedex 5, France
| | - Clément Morgat
- Department
of Nuclear Medicine, University Hospital
of Bordeaux, 33076 Bordeaux, France
- University
of Bordeaux, CNRS, EPHE, INCIA, UMR 5287, Bordeaux F-33000, France
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3
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Distinct In Vitro Binding Profile of the Somatostatin Receptor Subtype 2 Antagonist [ 177Lu]Lu-OPS201 Compared to the Agonist [ 177Lu]Lu-DOTA-TATE. Pharmaceuticals (Basel) 2021; 14:ph14121265. [PMID: 34959665 PMCID: PMC8706879 DOI: 10.3390/ph14121265] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 01/14/2023] Open
Abstract
Treatment of neuroendocrine tumours with the radiolabelled somatostatin receptor subtype 2 (SST2) peptide agonist [177Lu]Lu-DOTA-TATE is effective and well-established. Recent studies suggest improved therapeutic efficacy using the SST2 peptide antagonist [177Lu]Lu-OPS201. However, little is known about the cellular mechanisms that lead to the observed differences. In the present in vitro study, we compared kinetic binding, saturation binding, competition binding, cellular uptake and release of [177Lu]Lu-OPS201 versus [177Lu]Lu-DOTA-TATE using HEK cells stably transfected with the human SST2. While [177Lu]Lu-OPS201 and [177Lu]Lu-DOTA-TATE exhibited comparable affinity (KD, 0.15 ± 0.003 and 0.08 ± 0.02 nM, respectively), [177Lu]Lu-OPS201 recognized four times more binding sites than [177Lu]Lu-DOTA-TATE. Competition assays demonstrated that a high concentration of the agonist displaced only 30% of [177Lu]Lu-OPS201 bound to HEK-SST2 cell membranes; an indication that the antagonist binds to additional sites that are not recognized by the agonist. [177Lu]Lu-OPS201 showed faster association and slower dissociation than [177Lu]Lu-DOTA-TATE. Whereas most of [177Lu]Lu-OPS201 remained at the cell surface, [177Lu]Lu-DOTA-TATE was almost completely internalised inside the cell. The present data identified distinct differences between [177Lu]Lu-OPS201 and [177Lu]Lu-DOTA-TATE regarding the recognition of receptor binding sites (higher for [177Lu]Lu-OPS201) and their kinetics (faster association and slower dissociation of [177Lu]Lu-OPS201) that explain, to a great extent, the improved therapeutic efficacy of [177Lu]Lu-OPS201 compared to [177Lu]Lu-DOTA-TATE.
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Determination of neuropeptide Y Y1 receptor antagonist BIBP 3226 and evaluation of receptor expression based on liquid chromatography coupled with tandem mass spectrometry. Anal Bioanal Chem 2020; 412:6625-6632. [PMID: 32728863 DOI: 10.1007/s00216-020-02825-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 07/16/2020] [Indexed: 10/23/2022]
Abstract
Neuropeptide Y (NPY) is a peptide widely distributed throughout the body that is involved in various physiological processes, including the regulation of feeding behavior and energy homeostasis. 5-Carbamimidamido-2-(2,2-diphenylacetamido)-N-[(4-hydroxyphenyl)methyl]pentanamide (BIBP 3226) is a selective NPY Y1 receptor antagonist with recognized application in bone regeneration studies, requiring quantification at picogram levels. Hence, BIBP 3226 determination is proposed here by a validated HPLC-MS/MS method, based on a reversed-phase Kinetex® core-shell C8 column (2.6 μm, 150 × 2.1 mm) at 30 °C, elution in isocratic mode using a mixture of acetonitrile and water (30:70, v/v), containing 0.1% (v/v) formic acid, at 0.25 mL min-1, detection in positive ionization mode, and data acquisition in selected reaction monitoring mode. Calibration curves were linear for concentrations ranging from 0.25 to 30 ng mL-1 with LOD and LOQ values as low as 0.1 and 0.3 pg in cell extracts and 16 and 48 pg in supernatant culture media, respectively. BIBP 3226 was successfully determined in cell extracts and supernatants obtained from internalization assays. Using similar exposure conditions, the amount of BIBP 3226 found in breast cancer cells (MCF7) was 72 to 657 times higher than that found in bone marrow cells (Wt C57BL/6 mice), providing an indirect indicator of NPY Y1 receptor expression.
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Manoukian R, Sun H, Miller S, Shi D, Chan B, Xu C. Effects of monoclonal antagonist antibodies on calcitonin gene-related peptide receptor function and trafficking. J Headache Pain 2019; 20:44. [PMID: 31039731 PMCID: PMC6734291 DOI: 10.1186/s10194-019-0992-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 04/04/2019] [Indexed: 12/29/2022] Open
Abstract
Background Monoclonal antibodies against calcitonin gene-related peptide (CGRP) or its receptor are efficacious for the prevention of migraine headaches. The downstream molecular mechanisms following ligand-receptor blockade by which these antibodies prevent CGRP signaling through CGRP receptors have not been demonstrated. Methods Here we produced tool monoclonal functional antagonist antibodies against CGRP and its canonical receptor and developed a novel cellular model using fluorogen-activated protein technology that allows detection of CGRP receptor internalization by flow cytometry and, for an extended time course, visualization by confocal microscopy. Results Using this cell model we showed that these antagonist antibodies block both CGRP-induced cAMP signaling and CGRP receptor internalization. At least 10-fold higher concentrations of either antibody are necessary to block CGRP receptor internalization compared with cAMP accumulation in our cell model. Conclusion These data reinforce our understanding of how monoclonal functional antagonist antibodies interfere with CGRP signaling.
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Affiliation(s)
- Raffi Manoukian
- Department of Cytometry Sciences, Amgen Research, 360 Binney Street, Cambridge, MA, 02142, USA
| | - Hong Sun
- Department of Neuroscience, Amgen Research, 360 Binney Street, Cambridge, MA, 02142, USA
| | - Silke Miller
- Department of Neuroscience, Amgen Research, 360 Binney Street, Cambridge, MA, 02142, USA
| | - Di Shi
- Department of Neuroscience, Amgen Research, 360 Binney Street, Cambridge, MA, 02142, USA
| | - Brian Chan
- Department of Biologic Discovery, Amgen Research, 7990 Enterprise Street, Burnaby, BC, V5A1V7, Canada
| | - Cen Xu
- Department of Neuroscience, Amgen Research, One Amgen Center Dr., MS 29-2-B, Thousand Oaks, CA, 91320-1799, USA.
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Visualization of ligand-induced dopamine D 2S and D 2L receptor internalization by TIRF microscopy. Sci Rep 2017; 7:10894. [PMID: 28883522 PMCID: PMC5589927 DOI: 10.1038/s41598-017-11436-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 08/23/2017] [Indexed: 01/11/2023] Open
Abstract
G protein-coupled receptors (GPCRs), including the dopamine receptors, represent a group of important pharmacological targets. Upon agonist binding, GPCRs frequently undergo internalization, a process that is known to attenuate functional responses upon prolonged exposure to agonists. In this study, internalization was visualized by means of total internal reflection fluorescence (TIRF) microscopy at a level of discrete single events near the plasma membrane with high spatial resolution. A novel method has been developed to determine the relative extent of internalized fluorescent receptor-ligand complexes by comparative fluorescence quantification in living CHO cells. The procedure entails treatment with the reducing agent sodium borohydride, which converts cyanine-based fluorescent ligands on the membrane surface to a long-lived reduced form. Because the highly polar reducing agent is not able to pass the cell membrane, the fluorescent receptor-ligand complexes located in internalized compartments remain fluorescent under TIRF illumination. We applied the method to investigate differences of the short (D2S) and the long (D2L) isoforms of dopamine D2 receptors in their ability to undergo agonist-induced internalization.
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7
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Nederpelt I, Bunnik J, IJzerman AP, Heitman LH. Kinetic Profile of Neuropeptide–Receptor Interactions. Trends Neurosci 2016; 39:830-839. [DOI: 10.1016/j.tins.2016.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 09/26/2016] [Accepted: 09/27/2016] [Indexed: 01/18/2023]
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St-Jacques B, Ma W. Preferred recycling pathway by internalized PGE2 EP4 receptor following agonist stimulation in cultured dorsal root ganglion neurons contributes to enhanced EP4 receptor sensitivity. Neuroscience 2016; 326:56-68. [PMID: 27060485 DOI: 10.1016/j.neuroscience.2016.04.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 04/01/2016] [Accepted: 04/02/2016] [Indexed: 10/22/2022]
Abstract
Prostaglandin E2 (PGE2), a well-known pain mediator abundantly produced in injured tissues, sensitizes nociceptive dorsal root ganglion (DRG) neurons (nociceptors) through its four EP receptors (EP1-4). Our prior study showed that PGE2 or EP4 agonist stimulates EP4 externalization and this event was not only suppressed by the inhibitor of anterograde export, but also by the recycling inhibitor (St-Jacques and Ma, 2013). These data suggest that EP4 recycling also contributes to agonist-enhanced EP4 surface abundance. In the current study, we tested this hypothesis using antibody-feeding-based internalization assay, recycling assay and FITC-PGE2 binding assay. We observed that selective EP4 agonist 1-hydroxy-PGE1 (1-OH-PGE1) or CAY10850 time- and concentration-dependently increased EP4 internalization in cultured DRG neuron. Internalized EP4 was predominantly localized in the early endosomes and recycling endosomes, but rarely in the late endosomes and lysosomes. These observations were confirmed by FITC-PGE2 binding assay. We further revealed that 1-OH-PGE1 or CAY10850 time- and concentration-dependently increased EP4 recycling. Double exposures to 1-OH-PGE1 induced a greater increase in calcitonin gene-related peptide (CGRP) release than a single exposure or vehicle exposure, an event blocked by pre-treatment with the recycling inhibitor monensin. Our data suggest that EP4 recycling contributes to agonist-induced cell surface abundance and consequently enhanced receptor sensitivity. Facilitating EP4 externalization and recycling is a novel mechanism underlying PGE2-induced nociceptor sensitization.
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Affiliation(s)
- Bruno St-Jacques
- Douglas Mental Health University Institute, McGill University, Montréal, Québec H4H 1R3, Canada
| | - Weiya Ma
- Douglas Mental Health University Institute, McGill University, Montréal, Québec H4H 1R3, Canada; Department of Psychiatry, McGill University, Montréal, Québec H4H 1R3, Canada.
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Huynh AS, Estrella V, Stark VE, Cohen AS, Chen T, Casagni TJ, Josan JS, Lloyd MC, Johnson J, Hruby VJ, Vagner J, Morse DL. Tumor Targeting and Pharmacokinetics of a Near-Infrared Fluorescent-Labeled δ-Opioid Receptor Antagonist Agent, Dmt-Tic-Cy5. Mol Pharm 2016; 13:534-44. [PMID: 26713599 PMCID: PMC4936951 DOI: 10.1021/acs.molpharmaceut.5b00760] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Fluorescence molecular imaging can be employed for the development of novel cancer targeting agents. Herein, we investigated the pharmacokinetics (PK) and cellular uptake of Dmt-Tic-Cy5, a delta-opioid receptor (δOR) antagonist-fluorescent dye conjugate, as a tumor-targeting molecular imaging agent. δOR expression is observed normally in the CNS, and pathologically in some tumors, including lung liver and breast cancers. In vitro, in vivo, and ex vivo experiments were conducted to image and quantify the fluorescence signal associated with Dmt-Tic-Cy5 over time using in vitro and intravital fluorescence microscopy and small animal fluorescence imaging of tumor-bearing mice. We observed specific retention of Dmt-Tic-Cy5 in tumors with maximum uptake in δOR-expressing positive tumors at 3 h and observable persistence for >96 h; clearance from δOR nonexpressing negative tumors by 6 h; and systemic clearance from normal organs by 24 h. Live-cell and intravital fluorescence microscopy demonstrated that Dmt-Tic-Cy5 had sustained cell-surface binding lasting at least 24 h with gradual internalization over the initial 6 h following administration. Dmt-Tic-Cy5 is a δOR-targeted agent that exhibits long-lasting and specific signal in δOR-expressing tumors, is rapidly cleared from systemic circulation, and is not retained in non-δOR-expressing tissues. Hence, Dmt-Tic-Cy5 has potential as a fluorescent tumor imaging agent.
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Affiliation(s)
- Amanda Shanks Huynh
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Veronica Estrella
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Valerie E. Stark
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Allison S. Cohen
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Tingan Chen
- Analytic Microscopy Core, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Todd J. Casagni
- Department of Comparative Medicine, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive Tampa, FL 33612
| | - Jatinder S. Josan
- Department of Chemistry, The University of Arizona, 1306 E University Blvd., Tucson, AZ 85719
| | - Mark C. Lloyd
- Analytic Microscopy Core, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Joseph Johnson
- Analytic Microscopy Core, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
| | - Victor J. Hruby
- Department of Chemistry, The University of Arizona, 1306 E University Blvd., Tucson, AZ 85719
| | - Josef Vagner
- The BIO5 Research Institute, University of Arizona, 1657 E Helen Street, Tucson, Arizona 85721
| | - David L. Morse
- Department of Cancer Imaging & Metabolism, H. Lee Moffitt Cancer Center & Research Institute, 12902 Magnolia Drive, Tampa, FL 33612
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Li J, Tian Y, Wu A. Neuropeptide Y receptors: a promising target for cancer imaging and therapy. Regen Biomater 2015; 2:215-9. [PMID: 26816643 PMCID: PMC4669009 DOI: 10.1093/rb/rbv013] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 07/01/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022] Open
Abstract
Neuropeptide Y (NPY) was first identified from porcine brain in 1982, and plays its biological functions in humans through NPY receptors (Y1, Y2, Y4 and Y5). NPY receptors are known to mediate various physiological functions and involve in a majority of human diseases, such as obesity, hypertension, epilepsy and metabolic disorders. Recently, NPY receptors have been found to be overexpressed in many cancers, so they emerged as promising target in cancer diagnosis and therapy. This review focuses on the latest research about NPY and NPY receptors, and summarizes the current knowledge on NPY receptors expression in cancers, selective ligands for NPY receptors and their application in cancer imaging and therapy.
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Affiliation(s)
- Juan Li
- Key Laboratory of Magnetic Materials and Devices & Division of Functional Materials and Nano Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Yuchen Tian
- Key Laboratory of Magnetic Materials and Devices & Division of Functional Materials and Nano Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201, China
| | - Aiguo Wu
- Key Laboratory of Magnetic Materials and Devices & Division of Functional Materials and Nano Devices, Ningbo Institute of Materials Technology & Engineering, Chinese Academy of Sciences, Ningbo 315201, China
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Andressen KW, Manfra O, Brevik CH, Ulsund AH, Vanhoenacker P, Levy FO, Krobert KA. The atypical antipsychotics clozapine and olanzapine promote down-regulation and display functional selectivity at human 5-HT7 receptors. Br J Pharmacol 2015; 172:3846-60. [PMID: 25884989 PMCID: PMC4523340 DOI: 10.1111/bph.13169] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Revised: 04/01/2015] [Accepted: 04/14/2015] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND AND PURPOSE Classically, ligands of GPCRs have been classified primarily upon their affinity and efficacy to activate a signal transduction pathway. Recent reports indicate that the efficacy of a particular ligand can vary depending on the receptor-mediated response measured (e.g. activating G proteins, other downstream responses, internalization). Previously, we reported that inverse agonists induce both homo- and heterologous desensitization, similar to agonist stimulation, at the Gs -coupled 5-HT7 receptor. The primary objective of this study was to determine whether different inverse agonists at the 5-HT7 receptor also induce internalization and/or degradation of 5-HT7 receptors. EXPERIMENTAL APPROACH HEK293 cells expressing 5-HT7(a, b or d) receptors were pre-incubated with 5-HT, clozapine, olanzapine, mesulergine or SB269970 and their effects upon receptor density, AC activity, internalization, recruitment of β-arrestins and lysosomal trafficking were measured. KEY RESULTS The agonist 5-HT and three out of four inverse agonists tested increased internalization independently of β-arrestin recruitment. Among these, only the atypical antipsychotics clozapine and olanzapine promoted lysosomal sorting and reduced 5-HT7 receptor density (∼60% reduction within 24 h). Inhibition of lysosomal degradation with chloroquine blocked the clozapine- and olanzapine-induced down-regulation of 5-HT7 receptors. Incubation with SB269970 decreased both 5-HT7(b) constitutive internalization and receptor density but increased 5-HT7(d) receptor density, indicating differential ligand regulation among the 5-HT7 splice variants. CONCLUSIONS AND IMPLICATIONS Taken together, we found that various ligands differentially activate regulatory processes governing receptor internalization and degradation in addition to signal transduction. Thus, these data extend our understanding of functional selectivity at the 5-HT7 receptor.
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Affiliation(s)
- K W Andressen
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - O Manfra
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - C H Brevik
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway
| | - A H Ulsund
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - P Vanhoenacker
- Laboratory of Eukaryotic Gene Expression and Signal Transduction, Ghent University, Ghent, Belgium.,Intrexon ActoBiotics N.V., Technologiepark 4, Zwijnaarde, Belgium
| | - F O Levy
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - K A Krobert
- Department of Pharmacology, Institute of Clinical Medicine, University of Oslo and Oslo University Hospital, Oslo, Norway.,K.G. Jebsen Cardiac Research Centre and Center for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway
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Mountford SJ, Liu M, Zhang L, Groenen M, Herzog H, Holliday ND, Thompson PE. Synthetic routes to the Neuropeptide Y Y1 receptor antagonist 1229U91 and related analogues for SAR studies and cell-based imaging. Org Biomol Chem 2014; 12:3271-81. [PMID: 24733083 DOI: 10.1039/c4ob00176a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The potent Y1 receptor antagonist, 1229U91 has an unusual cyclic dimer structure that makes syntheses of analogue series quite challenging. We have examined three new routes to the synthesis of such peptides that has given access to novel structural variants including heterodimeric compounds, ring size variants and labelled conjugates. These compounds, including a fluorescently labelled analogue VIII show potent antagonism that can be utilised in studying Y1 receptor pharmacology.
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Affiliation(s)
- Simon J Mountford
- Medicinal Chemistry, Monash Institute of Pharmaceutical Sciences, 381 Royal Parade, Parkville, VIC 3052, Australia.
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13
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Rojas C, Raje M, Tsukamoto T, Slusher BS. Molecular mechanisms of 5-HT3 and NK1 receptor antagonists in prevention of emesis. Eur J Pharmacol 2014; 722:26-37. [DOI: 10.1016/j.ejphar.2013.08.049] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 07/01/2013] [Accepted: 08/03/2013] [Indexed: 11/26/2022]
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14
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Vummidi BR, Noreen F, Alzeer J, Moelling K, Luedtke NW. Photodynamic agents with anti-metastatic activities. ACS Chem Biol 2013; 8:1737-46. [PMID: 23672401 DOI: 10.1021/cb400008t] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A new concept in multifunctional anticancer agents is demonstrated. Tetrakis-(diisopropyl-guanidino) zinc phthalocyanine (Zn-DIGP) exhibits excellent properties as a photodynamic therapy (PDT) agent, as well as potential anti-metastatic activities in vivo. Zn-DIGP exhibits good cellular uptake and low toxicity in the dark (EC50 > 80 μM) and is well tolerated upon its intravenous injection into mice at 8 mg/kg. Upon photoexcitation with red laser light (660 nm), Zn-DIGP exhibits a high quantum yield for singlet oxygen formation (Φ ≈ 0.51) that results in potent phototoxicity to cell cultures (EC50 ≈ 0.16 μM). Zn-DIGP is also capable of inhibiting the formation of tumor colonies in the lungs of C57BL/6 mice injected with B16F10 cells. Zn-DIGP therefore inhibits cancer growth by both light-dependent and light-independent pathways. The anti-metastatic activities of Zn-DIGP possibly result from its ability to interfere with the signaling between chemokine CXCL10 and the G protein-coupled receptor CXCR3. Zn-DIGP is a competitive inhibitor of CXCR3 activation (IC50 = 3.8 μM) and selectively inhibits downstream events such as CXCL10-activated cell migration. Consistent with the presence of feedback regulation between CXCR3 binding and CXCL10 expression, Zn-DIGP causes overexpression of CXCL10. Interestingly, Zn-DIGP binds to CXCR3 without activating the receptor yet is able to cause endocytosis and degradation of this GPCR. To the best of our knowledge, Zn-DIGP is the first PDT agent that can facilitate the photodynamic treatment of primary tumors while simultaneously inhibiting the formation of metastatic tumor colonies by a light-independent mode of action.
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Affiliation(s)
- Balayeshwanth R. Vummidi
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057
Zurich, Switzerland
| | - Faiza Noreen
- Institute
of Medical Virology, University of Zurich, Gloriastrasse 30, CH-8006 Zurich,
Switzerland
| | - Jawad Alzeer
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057
Zurich, Switzerland
| | - Karin Moelling
- Institute
of Medical Virology, University of Zurich, Gloriastrasse 30, CH-8006 Zurich,
Switzerland
| | - Nathan W. Luedtke
- Department of Chemistry, University of Zurich, Winterthurerstrasse 190, CH-8057
Zurich, Switzerland
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15
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Muzzachi S, Blasi A, Ciani E, Favia M, Cardone RA, Marzulli D, Reshkin SJ, Merizzi G, Casavola V, Soleti A, Guerra L. MED1101: A new dialdehydic compound regulating P2×7 receptor cell surface expression in U937 cells. Biol Cell 2013; 105:399-413. [DOI: 10.1111/boc.201200088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Accepted: 05/24/2013] [Indexed: 12/17/2022]
Affiliation(s)
- Stefania Muzzachi
- Department of Biosciences; Biotechnologies and Biopharmaceutics; University of Bari; Bari; 70126; Italy
| | | | - Elena Ciani
- Department of Biosciences; Biotechnologies and Biopharmaceutics; University of Bari; Bari; 70126; Italy
| | - Maria Favia
- Department of Biosciences; Biotechnologies and Biopharmaceutics; University of Bari; Bari; 70126; Italy
| | - Rosa A. Cardone
- Department of Biosciences; Biotechnologies and Biopharmaceutics; University of Bari; Bari; 70126; Italy
| | - Domenico Marzulli
- Institute of Biomembranes and Bioenergetics; CNR; Bari; 70126; Italy
| | - Stephan J. Reshkin
- Department of Biosciences; Biotechnologies and Biopharmaceutics; University of Bari; Bari; 70126; Italy
| | | | - Valeria Casavola
- Department of Biosciences; Biotechnologies and Biopharmaceutics; University of Bari; Bari; 70126; Italy
| | | | - Lorenzo Guerra
- Department of Biosciences; Biotechnologies and Biopharmaceutics; University of Bari; Bari; 70126; Italy
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16
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Allosteric modulation of an excitatory amino acid transporter: the subtype-selective inhibitor UCPH-101 exerts sustained inhibition of EAAT1 through an intramonomeric site in the trimerization domain. J Neurosci 2013; 33:1068-87. [PMID: 23325245 DOI: 10.1523/jneurosci.3396-12.2013] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In the present study, the mechanism of action and molecular basis for the activity of the first class of selective inhibitors of the human excitatory amino acid transporter subtype 1 (EAAT1) and its rodent ortholog GLAST are elucidated. The previously reported specificity of UCPH-101 and UCPH-102 for EAAT1 over EAAT2 and EAAT3 is demonstrated to extend to the EAAT4 and EAAT5 subtypes as well. Interestingly, brief exposure to UCPH-101 induces a long-lasting inactive state of EAAT1, whereas the inhibition exerted by closely related analogs is substantially more reversible in nature. In agreement with this, the kinetic properties of UCPH-101 unblocking of the transporter are considerably slower than those of UCPH-102. UCPH-101 exhibits noncompetitive inhibition of EAAT1, and its binding site in GLAST has been delineated in an elaborate mutagenesis study. Substitutions of several residues in TM3, TM4c, and TM7a of GLAST have detrimental effects on the inhibitory potency and/or efficacy of UCPH-101 while not affecting the pharmacological properties of (S)-glutamate or the competitive EAAT inhibitor TBOA significantly. Hence, UCPH-101 is proposed to target a predominantly hydrophobic crevice in the "trimerization domain" of the GLAST monomer, and the inhibitor is demonstrated to inhibit the uptake through the monomer that it binds to exclusively and not to affect substrate translocation through the other monomers in the GLAST trimer. The allosteric mode of UCPH-101 inhibition underlines the functional importance of the trimerization domain of the EAAT and demonstrates the feasibility of modulating transporter function through ligand binding to regions distant from its "transport domain."
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17
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Masuda R, Oishi S, Tanahara N, Ohno H, Hirasawa A, Tsujimoto G, Yano Y, Matsuzaki K, Navenot JM, Peiper SC, Fujii N. Paradoxical Downregulation of CXC Chemokine Receptor 4 Induced by Polyphemusin II-Derived Antagonists. Bioconjug Chem 2012; 23:1259-65. [DOI: 10.1021/bc300084h] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ryo Masuda
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
| | - Shinya Oishi
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
| | - Noriko Tanahara
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
| | - Hiroaki Ohno
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
| | - Akira Hirasawa
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
| | - Gozoh Tsujimoto
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
| | - Yoshiaki Yano
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
| | - Katsumi Matsuzaki
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
| | - Jean-Marc Navenot
- Department
of Pathology, Anatomy
and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, United States
| | - Stephen C. Peiper
- Department
of Pathology, Anatomy
and Cell Biology, Thomas Jefferson University, Philadelphia, Pennsylvania 19107, United States
| | - Nobutaka Fujii
- Graduate School of Pharmaceutical
Sciences, Kyoto University, Sakyo-ku, Kyoto
606-8501, Japan
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18
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Rojas C, Slusher BS. Pharmacological mechanisms of 5-HT₃ and tachykinin NK₁ receptor antagonism to prevent chemotherapy-induced nausea and vomiting. Eur J Pharmacol 2012; 684:1-7. [PMID: 22425650 DOI: 10.1016/j.ejphar.2012.01.046] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Revised: 01/23/2012] [Accepted: 01/28/2012] [Indexed: 10/28/2022]
Abstract
Nausea and vomiting are among the most common and distressing consequences of cytotoxic chemotherapies. Nausea and vomiting can be acute (0-24h) or delayed (24-72 h) after chemotherapy administration. The introduction of 5-HT(3) receptor antagonists in the 90s was a major advance in the prevention of acute emesis. These receptor antagonists exhibited similar control on acute emesis but had no effect on delayed emesis. These findings led to the hypothesis that serotonin plays a central role in the mechanism of acute emesis but a lesser role in the pathogenesis of delayed emesis. In contrast, delayed emesis has been largely associated with the activation of neurokinin 1 (NK(1)) receptors by substance P. However, in 2003, a new 5-HT(3) receptor antagonist was introduced into the market; unlike first generation 5-HT(3) receptor antagonists, palonosetron was found to be effective in preventing both acute and delayed chemotherapy induced nausea and vomiting. Recent mechanistic studies have shown that palonosetron, in contrast to first generation receptor antagonists, exhibits allosteric binding to the 5-HT(3) receptor, positive cooperativity, persistent inhibition of receptor function after the drug is removed and triggers 5-HT(3) receptor internalization. Further, in vitro and in vivo experiments have shown that palonosetron can inhibit substance P-mediated responses, presumably through its unique interactions with the 5-HT(3) receptor. It appears that the crossroads of acute and delayed emeses include interactions among the 5-HT(3) and NK(1) receptor neurotransmitter pathways and that inhibitions of these interactions lend the possibility of improved treatment that encompasses both acute and delayed emeses.
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Affiliation(s)
- Camilo Rojas
- Brain Science Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21224-6515, USA
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19
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Stallaert W, Christopoulos A, Bouvier M. Ligand functional selectivity and quantitative pharmacology at G protein-coupled receptors. Expert Opin Drug Discov 2011; 6:811-25. [DOI: 10.1517/17460441.2011.586691] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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20
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Walther C, Mörl K, Beck-Sickinger AG. Neuropeptide Y receptors: ligand binding and trafficking suggest novel approaches in drug development. J Pept Sci 2011; 17:233-46. [PMID: 21351324 DOI: 10.1002/psc.1357] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Revised: 12/22/2010] [Accepted: 01/07/2011] [Indexed: 12/27/2022]
Abstract
NPY, PYY and PP constitute the so-called NPY hormone family, which exert its biological functions in humans through YRs (Y₁, Y₂, Y₄ and Y₅). Systematic modulation of YR function became important as this multireceptor/multiligand system is known to mediate various essential physiological key functions and is involved in a variety of major human diseases such as epilepsy, obesity and cancer. As several YRs have been found to be overexpressed on different types of malignant tumors they emerge as promising target in modern drug development. Here, we summarize the current understanding of YRs function and the molecular mechanisms of ligand binding and trafficking. We further address recent advances in YR-based drug design, the development of promising future drug candidates and novel approaches in YR-targeted tumor diagnostics and therapy opportunities.
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Affiliation(s)
- Cornelia Walther
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, Leipzig University, Leipzig, Germany
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21
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Viso A, Fernández de la Pradilla R, Tortosa M, García A, Flores A. Update 1 of: α,β-Diamino Acids: Biological Significance and Synthetic Approaches. Chem Rev 2011; 111:PR1-42. [DOI: 10.1021/cr100127y] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Affiliation(s)
- Alma Viso
- Instituto de Química Orgánica, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | | | - Mariola Tortosa
- Instituto de Química Orgánica, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Ana García
- Instituto de Química Orgánica, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
| | - Aida Flores
- Instituto de Química Orgánica, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain
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22
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Abstract
Constitutively active mutants (CAMs) of G-protein-coupled receptors mimic the active conformation of the receptor in their ability to activate second messenger systems in the absence of agonist. They have revealed novel properties of drugs that reverse the basal levels of constitutive activity, indicating that the drugs have the inverse agonist activity. Internalization plays an important role in receptor endocytosis and signal transduction. The present chapter provides the investigation of the internalization behavior of CAM N111G of Angiotensin II type 1 (AT(1)) receptor and correlates the result with the mechanism of constitutive activity of the mutant. Both wild-type (WT) and N111G mutant receptors were transiently expressed in COS-7 cells and total inositol phosphate production was measured in presence and absence of the angiotensin II receptor blockers (ARBs). The binding affinities toward agonist and ARBs were also determined. We found that the ARBs have the inverse agonist activity in CAM N111G of AT(1) receptor. The internalization of the mutant, which was much lower than WT receptor, was significantly increased in presence of the ARBs. The results indicate that internalization of CAM N111G of AT(1) receptor is induced by the ARBs, which may be an important characteristic of inverse agonist activities of the ARBs in N111G.
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23
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Estes AM, McAllen K, Parker MS, Sah R, Sweatman T, Park EA, Balasubramaniam A, Sallee FR, Walker MW, Parker SL. Maintenance of Y receptor dimers in epithelial cells depends on interaction with G-protein heterotrimers. Amino Acids 2010; 40:371-80. [DOI: 10.1007/s00726-010-0642-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Accepted: 05/25/2010] [Indexed: 12/01/2022]
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24
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Li G, Shi Y, Huang H, Zhang Y, Wu K, Luo J, Sun Y, Lu J, Benovic JL, Zhou N. Internalization of the human nicotinic acid receptor GPR109A is regulated by G(i), GRK2, and arrestin3. J Biol Chem 2010; 285:22605-18. [PMID: 20460384 DOI: 10.1074/jbc.m109.087213] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Nicotinic acid (niacin) has been widely used as a favorable lipid-lowering drug for several decades, and the orphan G protein-coupled receptor GPR109A has been identified to be a receptor for niacin. Mechanistic investigations have shown that as a G(i)-coupled receptor, GPR109A inhibits adenylate cyclase activity upon niacin activation, thereby inhibiting free fatty acid liberation. However, the underlying molecular mechanisms that regulate signaling and internalization of GPR109A remain largely unknown. To further characterize GPR109A internalization, we made a construct to express GPR109A fused with enhanced green fluorescent protein (EGFP) at its carboxyl-terminal end. In stable GPR109A-EGFP-expressing HEK-293 cells, GPR109A-EGFP was mainly localized at the plasma membrane and was rapidly internalized in a dose- and time-dependent manner upon agonist stimulation. GPR109A internalization was completely blocked by hypertonic sucrose, indicating that GPR109A internalizes via the clathrin-coated pit pathway. Further investigation demonstrated that internalized GPR109A was recycled to the cell surface after the removal of agonist, and recycling of the internalized receptors was not blocked by treatment with acidotropic agents, NH(4)Cl and monensin. Pertussis toxin pretreatment not only inhibited forskolin-induced cAMP accumulation and intracellular Ca(2+) mobilization; it also significantly attenuated agonist-promoted GPR109A internalization. Moreover, RNA interference experiments showed that knockdown of GRK2 (G protein-coupled receptor kinase 2) and arrestin3 expression significantly impaired receptor internalization. Taken together, these results indicate that the agonist-induced internalization of GPR109A receptors is regulated by GRK2 and arrestin3 in a pertussis toxin-sensitive manner and that internalized receptor recycling is independent of endosomal acidification.
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Affiliation(s)
- Guo Li
- Institute of Biochemistry, College of Life Science, Zijingang Campus, Zhejiang University, Hangzhou, Zhejiang 310058, China
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Kilpatrick LE, Briddon SJ, Hill SJ, Holliday ND. Quantitative analysis of neuropeptide Y receptor association with beta-arrestin2 measured by bimolecular fluorescence complementation. Br J Pharmacol 2010; 160:892-906. [PMID: 20438572 PMCID: PMC2901518 DOI: 10.1111/j.1476-5381.2010.00676.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE beta-Arrestins are critical scaffold proteins that shape spatiotemporal signalling from seven transmembrane domain receptors (7TMRs). Here, we study the association between neuropeptide Y (NPY) receptors and beta-arrestin2, using bimolecular fluorescence complementation (BiFC) to directly report underlying protein-protein interactions. EXPERIMENTAL APPROACH Y1 receptors were tagged with a C-terminal fragment, Yc, of yellow fluorescent protein (YFP), and beta-arrestin2 fused with the complementary N-terminal fragment, Yn. After Y receptor-beta-arrestin association, YFP fragment refolding to regenerate fluorescence (BiFC) was examined by confocal microscopy in transfected HEK293 cells. Y receptor/beta-arrestin2 BiFC responses were also quantified by automated imaging and granularity analysis. KEY RESULTS NPY stimulation promoted association between Y1-Yc and beta-arrestin2-Yn, and the specific development of BiFC in intracellular compartments, eliminated when using non-interacting receptor and arrestin mutants. Responses developed irreversibly and were slower than for downstream Y1 receptor-YFP internalization, a consequence of delayed maturation and stability of complemented YFP. However, beta-arrestin2 BiFC measurements delivered appropriate ligand pharmacology for both Y1 and Y2 receptors, and demonstrated higher affinity of Y1 compared to Y2 receptors for beta-arrestin2. Receptor mutagenesis combined with beta-arrestin2 BiFC revealed that alternative arrangements of Ser/Thr residues in the Y1 receptor C tail could support beta-arrestin2 association, and that Y2 receptor-beta-arrestin2 interaction was enhanced by the intracellular loop mutation H155P. CONCLUSIONS AND IMPLICATIONS The BiFC approach quantifies Y receptor ligand pharmacology focused on the beta-arrestin2 pathway, and provides insight into mechanisms of beta-arrestin2 recruitment by activated and phosphorylated 7TMRs, at the level of protein-protein interaction.
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Affiliation(s)
- L E Kilpatrick
- Institute of Cell Signalling, School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK
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26
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Böhme I, Beck-Sickinger AG. Illuminating the life of GPCRs. Cell Commun Signal 2009; 7:16. [PMID: 19602276 PMCID: PMC2726148 DOI: 10.1186/1478-811x-7-16] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2009] [Accepted: 07/14/2009] [Indexed: 01/19/2023] Open
Abstract
The investigation of biological systems highly depends on the possibilities that allow scientists to visualize and quantify biomolecules and their related activities in real-time and non-invasively. G-protein coupled receptors represent a family of very dynamic and highly regulated transmembrane proteins that are involved in various important physiological processes. Since their localization is not confined to the cell surface they have been a very attractive "moving target" and the understanding of their intracellular pathways as well as the identified protein-protein-interactions has had implications for therapeutic interventions. Recent and ongoing advances in both the establishment of a variety of labeling methods and the improvement of measuring and analyzing instrumentation, have made fluorescence techniques to an indispensable tool for GPCR imaging. The illumination of their complex life cycle, which includes receptor biosynthesis, membrane targeting, ligand binding, signaling, internalization, recycling and degradation, will provide new insights into the relationship between spatial receptor distribution and function. This review covers the existing technologies to track GPCRs in living cells. Fluorescent ligands, antibodies, auto-fluorescent proteins as well as the evolving technologies for chemical labeling with peptide- and protein-tags are described and their major applications concerning the GPCR life cycle are presented.
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Affiliation(s)
- Ilka Böhme
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, Leipzig University, Brüderstr, 34, 04103 Leipzig, Germany.
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27
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Functional characterization of human variants of the mu-opioid receptor gene. Proc Natl Acad Sci U S A 2009; 106:10811-6. [PMID: 19528663 DOI: 10.1073/pnas.0904509106] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Opioids and their receptors have an important role in analgesia and alcohol and substance use disorders (ASUD). We have identified several naturally occurring amino acid changing variants of the human mu-opioid receptor (MOR), and assessed the functional consequences of these previously undescribed variants in stably expressing cell lines. Several of these variants had altered trafficking and signaling properties. We found that an L85I variant showed significant internalization in response to morphine, in contrast to the WT MOR, which did not internalize in response to morphine. Also, when L85I and WT receptor were coexpressed, WT MOR internalized with the L85I MOR, suggesting that, in the heterozygous condition, the L85I phenotype would be dominant. This finding is potentially important, because receptor internalization has been associated with development of tolerance to opiate analgesics. In contrast, an R181C variant abolished both signaling and internalization in response to saturating doses of the hydrolysis-resistant enkephalin [D-Ala2,N-MePhe4,Gly5-ol]enkephalin (DAMGO). Coexpression of the R181C and WT receptor led to independent trafficking of the 2 receptors. S42T and C192F variants showed a rightward shift in potency of both morphine and DAMGO, whereas the S147C variant displayed a subtle leftward shift in morphine potency. These data suggest that these and other such variants may have clinical relevance to opioid responsiveness to both endogenous ligands and exogenous drugs, and could influence a broad range of phenotypes, including ASUD, pain responses, and the development of tolerance to morphine.
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28
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Noé F, Frasca A, Balducci C, Carli M, Sperk G, Ferraguti F, Pitkänen A, Bland R, Fitzsimons H, During M, Vezzani A. Neuropeptide Y overexpression using recombinant adeno-associated viral vectors. Neurotherapeutics 2009; 6:300-6. [PMID: 19332323 PMCID: PMC5084207 DOI: 10.1016/j.nurt.2009.01.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 01/20/2009] [Accepted: 01/22/2009] [Indexed: 10/21/2022] Open
Abstract
Gene therapy may represent a promising alternative treatment of epileptic patients who are resistant to conventional anti-epileptic drugs. Among the various approaches for the application of gene therapy in the treatment of CNS disorders, recombinant adeno-associated viral (AAV) vectors have been most widely used. Preclinical studies using a selection of "therapeutic" genes injected into the rodent brain to correct the compromised balance between inhibitory and excitatory transmission in epilepsy, showed significant reduction of seizures and inhibition of epileptogenesis. In particular, transduction of neuropeptide genes, such as galanin and neuropeptide Y (NPY) in specific brain areas in experimental models of seizures resulted in significant anticonvulsant effects. Recent findings showed a long-lasting NPY over-expression in the rat hippocampus by local application of recombinant AAV vectors associated with reduced generalization of seizures, delayed kindling epileptogenesis, and strong reduction of chronic spontaneous seizures. These results establish a proof-of-principle evidence of the efficacy of gene therapy as anticonvulsant treatment. Additional investigations are required to address safety concerns and possible side effects in more detail.
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Affiliation(s)
- Francesco Noé
- grid.4527.40000000106678902Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via G. La Masa 19, 20156 Milano, Italy
| | - Angelisa Frasca
- grid.4527.40000000106678902Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via G. La Masa 19, 20156 Milano, Italy
| | - Claudia Balducci
- grid.4527.40000000106678902Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via G. La Masa 19, 20156 Milano, Italy
| | - Mirjana Carli
- grid.4527.40000000106678902Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via G. La Masa 19, 20156 Milano, Italy
| | - Gunther Sperk
- grid.5361.10000000088532677Department of Pharmacology, Medical University, A-6020 Innsbruck, Austria
| | - Francesco Ferraguti
- grid.5361.10000000088532677Department of Pharmacology, Medical University, A-6020 Innsbruck, Austria
| | - Asla Pitkänen
- grid.9668.10000000107262490Epilepsy Research Lab, A.I. Virtanen Institute for Molecular Science, University of Kuopio, FI-70211 Kuopio, Finland
- grid.410705.7000000040628207XDepartment of Neurology, Kuopio University Hospital, FI-70211 Kuopio, Finland
| | - Ross Bland
- Neurologix, Inc., 07024 Fort Lee, New Jersey
- grid.261331.40000000122857943Human Cancer Genetics Programme, The Ohio State University, 43210 Columbus, Ohio
| | - Helen Fitzsimons
- Neurologix, Inc., 07024 Fort Lee, New Jersey
- grid.261331.40000000122857943Human Cancer Genetics Programme, The Ohio State University, 43210 Columbus, Ohio
| | - Matthew During
- grid.261331.40000000122857943Human Cancer Genetics Programme, The Ohio State University, 43210 Columbus, Ohio
| | - Annamaria Vezzani
- grid.4527.40000000106678902Department of Neuroscience, Mario Negri Institute for Pharmacological Research, Via G. La Masa 19, 20156 Milano, Italy
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Bhuiyan MA, Hossain M, Miura SI, Nakamura T, Ozaki M, Nagatomo T. Constitutively Active Mutant N111G of Angiotensin II Type 1 (AT1) Receptor Induces Homologous Internalization Through Mediation of AT1-Receptor Antagonist. J Pharmacol Sci 2009; 111:227-34. [DOI: 10.1254/jphs.09202fp] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Lederman MM, Jump R, Pilch-Cooper HA, Root M, Sieg SF. Topical application of entry inhibitors as "virustats" to prevent sexual transmission of HIV infection. Retrovirology 2008; 5:116. [PMID: 19094217 PMCID: PMC2637900 DOI: 10.1186/1742-4690-5-116] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2008] [Accepted: 12/18/2008] [Indexed: 11/10/2022] Open
Abstract
With the continuing march of the AIDS epidemic and little hope for an effective vaccine in the near future, work to develop a topical strategy to prevent HIV infection is increasingly important. This stated, the track record of large scale "microbicide" trials has been disappointing with nonspecific inhibitors either failing to protect women from infection or even increasing HIV acquisition. Newer strategies that target directly the elements needed for viral entry into cells have shown promise in non-human primate models of HIV transmission and as these agents have not yet been broadly introduced in regions of highest HIV prevalence, they are particularly attractive for prophylaxis. We review here the agents that can block HIV cellular entry and that show promise as topical strategies or "virustats" to prevent mucosal transmission of HIV infection.
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Affiliation(s)
- Michael M Lederman
- Department of Medicine, Case Western Reserve University, 1100 Euclid Ave, Cleveland, OH 44118, USA
| | - Robin Jump
- Department of Medicine, Case Western Reserve University, 1100 Euclid Ave, Cleveland, OH 44118, USA
| | - Heather A Pilch-Cooper
- Department of Medicine, Case Western Reserve University, 1100 Euclid Ave, Cleveland, OH 44118, USA
| | - Michael Root
- Kimmel Cancer Center, Thomas Jefferson University, 233 South 10th Street, Philadelphia PA, 19107, USA
| | - Scott F Sieg
- Department of Medicine, Case Western Reserve University, 1100 Euclid Ave, Cleveland, OH 44118, USA
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Böhme I, Stichel J, Walther C, Mörl K, Beck-Sickinger AG. Agonist induced receptor internalization of neuropeptide Y receptor subtypes depends on third intracellular loop and C-terminus. Cell Signal 2008; 20:1740-9. [DOI: 10.1016/j.cellsig.2008.05.017] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 05/26/2008] [Indexed: 10/22/2022]
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Noè F, Pool AH, Nissinen J, Gobbi M, Bland R, Rizzi M, Balducci C, Ferraguti F, Sperk G, During MJ, Pitkänen A, Vezzani A. Neuropeptide Y gene therapy decreases chronic spontaneous seizures in a rat model of temporal lobe epilepsy. Brain 2008; 131:1506-15. [DOI: 10.1093/brain/awn079] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Vercauteren FGG, Flores G, Ma W, Chabot JG, Geenen L, Clerens S, Fazel A, Bergeron JJM, Srivastava LK, Arckens L, Quirion R. An organelle proteomic method to study neurotransmission-related proteins, applied to a neurodevelopmental model of schizophrenia. Proteomics 2008; 7:3569-79. [PMID: 17907268 DOI: 10.1002/pmic.200700379] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Limited information is currently available on molecular events that underlie schizophrenia-like behaviors in animal models. Accordingly, we developed an organelle proteomic approach enabling the study of neurotransmission-related proteins in the prefrontal cortex (PFC) of postpubertal (postnatal day 60 (PD60)) neonatally ventral hippocampal (nVH) lesioned rats, an extensively used neurodevelopmental model of schizophrenia-like behaviors. The PFC was chosen because of its purported role in the etiology of the disease. Statistical analysis of 392 reproducible spots on 2-D organelle proteomic patterns revealed significant changes in intensity of 18 proteinous spots in plasma membrane-enriched fractions obtained from postpubertal nVH lesioned rats compared to controls. Mass spectrometric analysis and database searching allowed the identification of a single protein in each of the nine differential spots, including proteins of low abundance, such as neurocalcin delta. Most of the identified dysregulated proteins, including clathrin light chain B, syntaxin binding protein 1b and visinin-like protein 1 are known to be linked to various neurotransmitter systems and to play key roles in plasma membrane receptor expression and recycling as well as synaptic vesicle exocytosis/recycling. Organelle proteomic approaches have hence proved to be most useful to identify key proteins linked to a given behavior in animal models of brain diseases.
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Affiliation(s)
- Freya G G Vercauteren
- Department of Psychiatry, Douglas Mental Health University Institute, McGill University, Montréal, Québec, Canada
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Abstract
Obesity is a serious public health problem throughout the world, affecting both developed societies and developing countries. The central nervous system has developed a meticulously interconnected circuitry in order to keep us fed and in an adequate nutritional state. One of these consequences is that an energy-dense environment favors the development of obesity. Neuropeptide Y (NPY) is one of the most abundant and widely distributed peptides in the central nervous system of both rodents and humans and has been implicated in a variety of physiological actions. Within the hypothalamus, NPY plays an essential role in the control of food intake and body weight. Centrally administered NPY causes robust increases in food intake and body weight and, with chronic administration, can eventually produce obesity. NPY activates a population of at least six G protein-coupled Y receptors. NPY analogs exhibit varying degrees of affinity and specificity for these Y receptors. There has been renewed speculation that ligands for Y receptors may be of benefit for the treatment of obesity. This review highlights the therapeutic potential of Y(1), Y(2), Y(4), and Y(5) receptor agonists and antagonists as additional intervention to treat human obesity.
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Affiliation(s)
- M M Kamiji
- Department of Gastroenterology, Faculty of Medicine, University of Sao Paulo, Ribeirão Preto Campus 14048-900, Ribeirão Preto-SP, Brazil
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Fishman P, Jacobson K, Ochaion A, Cohen S, Bar-Yehuda S. The Anti-Cancer Effect of A 3 Adenosine Receptor Agonists: A Novel, Targeted Therapy. IMMUNOLOGY, ENDOCRINE & METABOLIC AGENTS IN MEDICINAL CHEMISTRY 2007; 7:298-303. [PMID: 34824647 PMCID: PMC8611655 DOI: 10.2174/187152207781369878] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The A3 adenosine receptor (A3AR) is highly expressed in various human solid tumor cells whereas low expression is found in the adjacent normal tissues. Activation of the A3AR with synthetic highly selective agonists, such as IB-MECA, Cl-IB-MECA or LJ529, induces tumor growth inhibition of melanoma, lymphoma, breast, hepatoma, prostate and colon carcinoma cells both in vitro and in vivo. Two molecular events take place upon receptor activation and include: a. receptor internalization and subsequent degradation, followed by decreased receptor mRNA and protein expression level. b. modulation of down-stream signal transduction pathways, including those related to Wnt and NF-κB. Subsequently, the levels of cyclin D1 and c-Myc are decreased leading to tumor growth inhibition. IB-MECA synergizes with chemotherapeutic agents to yield an additive anti-tumor effect and protects against myelotoxicity induced by chemotherapy. Taken together, A3AR agonists may be suggested as a new family of orally bioavailable compounds to be developed as potent inhibitors of malignant diseases.
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Affiliation(s)
- P. Fishman
- Can-Fite BioPharma Ltd., Kiryat-Matalon, Petah -Tikva, 49170, Israel
| | - K.A. Jacobson
- Molecular Recognition Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - A. Ochaion
- Can-Fite BioPharma Ltd., Kiryat-Matalon, Petah -Tikva, 49170, Israel
| | - S. Cohen
- Can-Fite BioPharma Ltd., Kiryat-Matalon, Petah -Tikva, 49170, Israel
| | - S. Bar-Yehuda
- Can-Fite BioPharma Ltd., Kiryat-Matalon, Petah -Tikva, 49170, Israel
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36
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Galandrin S, Oligny-Longpré G, Bouvier M. The evasive nature of drug efficacy: implications for drug discovery. Trends Pharmacol Sci 2007; 28:423-30. [PMID: 17659355 DOI: 10.1016/j.tips.2007.06.005] [Citation(s) in RCA: 289] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 05/23/2007] [Accepted: 06/27/2007] [Indexed: 11/26/2022]
Abstract
The efficacy of a drug is generally determined by the drug's ability to promote a quantifiable biological response. In the context of the classical receptor-occupancy theory, the efficacy is considered an intrinsic property of the ligand/receptor pair, and it is often assumed to be the same for all the responses evoked by this pair. The recognition that a single receptor can engage different signalling pathways and that various drugs binding to this receptor might differentially influence each of these pathways led to the reassessment of the efficacy concept. Of particular notice is the fact that ligands that behave as agonists toward a given signalling pathway can act, through the same receptor, as antagonists or even inverse agonists on a different pathway in the same cell. These observations, variously referred to as 'ligand-directed trafficking of receptor signalling' (LDTRS), 'functional selectivity', 'biased agonism', 'ligand-biased efficacy', 'collateral efficacy' or 'pluridimensional efficacy', have important implications for the molecular definition of efficacy and the process of drug discovery.
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Affiliation(s)
- Ségolène Galandrin
- Department of Biochemistry and Groupe de Recherche Universitaire sur le Médicament, Institute for Research in Immunology and Cancer, Université de Montréal, Montréal (Québec), H3C 3J7, Canada
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Kenakin T. Collateral efficacy in drug discovery: taking advantage of the good (allosteric) nature of 7TM receptors. Trends Pharmacol Sci 2007; 28:407-15. [PMID: 17629960 DOI: 10.1016/j.tips.2007.06.009] [Citation(s) in RCA: 140] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2006] [Revised: 05/25/2007] [Accepted: 06/29/2007] [Indexed: 10/23/2022]
Abstract
Seven-transmembrane receptors are prototypic allosteric proteins with the ability to adopt numerous conformations, many of which interact with cellular partners to initiate cellular biochemical processes. Defining efficacy as the ability of ligands to stabilize some of these conformations (which, in turn, possess physiological activity) presents a wider definition of efficacy beyond simple integrated cellular response; numerous or 'pluridimensional' efficacies are required to describe ligands. Specifically, some agonists might only partially activate the library of potential signaling systems in a cell or some antagonists might actively induce receptor internalization without activation. This article reviews data to demonstrate that there is no longer support for a linear view of efficacy whereby a single receptor activation state triggers all possible receptor interactions with a cell. Instead, a view of collateral efficacy, in which ligands can produce portions of the possible behaviors of receptors, is presented. Concepts related to the molecular mechanism for this effect (discussed in the literature as 'stimulus trafficking', 'biased agonism' or 'functional selectivity') and discussion of the possible therapeutic implications of this mechanism are presented.
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Affiliation(s)
- Terry Kenakin
- Department of Biochemical Reagents and Assay Development, GlaxoSmithKline Research and Development, 5 Moore Drive, Research Triangle Park, NC 27709, USA.
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38
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Böhme I, Mörl K, Bamming D, Meyer C, Beck-Sickinger AG. Tracking of human Y receptors in living cells--a fluorescence approach. Peptides 2007; 28:226-34. [PMID: 17207557 DOI: 10.1016/j.peptides.2006.08.042] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2006] [Accepted: 08/20/2006] [Indexed: 11/25/2022]
Abstract
Non-invasive methods for studying biological processes in living cells have become very important, also in the field of GPCR biochemistry. Great advancements in the application of fluorescence techniques as well as in the development and improvement of novel fluorophores allow the visualization of dynamic processes. Using these technologies, problems concerning receptor biosynthesis, internalization, recycling and degradation can be investigated. Here we compare the application of the different fluorescent tags EYFP, Lumiotrade mark and SNAPtrade mark to track hY(1) and hY(5) receptors in living cells.
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Affiliation(s)
- Ilka Böhme
- Institute of Biochemistry, Faculty of Biosciences, Pharmacy and Psychology, University of Leipzig, Brüderstr. 34, D-04103 Leipzig, Germany
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Gehlert DR, Shaw JL. Increased brain neuropeptide Y1 and Y2 receptor binding in NPY knock out mice does not result in increased receptor function. Peptides 2007; 28:241-9. [PMID: 17208335 DOI: 10.1016/j.peptides.2006.08.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2006] [Accepted: 08/20/2006] [Indexed: 10/23/2022]
Abstract
The brain neuropeptide Neuropeptide Y (NPY) is an important modulator of a number of centrally mediated processes including feeding, anxiety-like behaviors, blood pressure and others. NPY produces its effects through at least four functional G-protein coupled receptors termed Y1, Y2, Y4 and Y5. In the brain, the Y1 and Y2 receptor subtypes are the predominant receptor population. To better understand the roles of NPY, genetically modified mice lacking NPY were produced but lacked the expected phenotypes. These mice have previously been reported to have a marked increase in Y2 receptor binding. In the present study, we found an upregulation of both Y1 and Y2 receptor binding and extended these findings to the female. These increases were as large as 10-fold or greater in many brain regions. To assess functional coupling of the receptors, we performed agonist-induced [(35)S]GTPgammaS autoradiography. In the mouse brain, the Y1/Y4/Y5 agonist Leu(31),Pro(34)-NPY increased [(35)S]GTPgammaS binding with a regional distribution consistent with that produced when labeling adjacent sections with [(125)I]-Leu(31),Pro(34)-PYY. In a few brain regions, minor increases were noted in the agonist-induced binding when comparing knock out mice to wild type. The Y2 agonist C2-NPY stimulated [(35)S]GTPgammaS binding in numerous brain areas with a regional distribution similar to the binding observed with [(125)I]-PYY3-36. Again, no major increases were noted in the functional activation of Y2 receptors between knock out and wild type mice. Therefore, the increased Y1 and Y2 binding observed in the NPY knock out mice does not represent an increase in NPY receptor mediated signaling and is likely due to an increase in spare (uncoupled) receptors.
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Affiliation(s)
- Donald R Gehlert
- Neuroscience Research, Mail Code 0510, Lilly Research Laboratories, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN 46285, USA.
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40
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Kenakin T. Collateral efficacy as a pharmacological problem applied to new drug discovery. Expert Opin Drug Discov 2006; 1:635-52. [DOI: 10.1517/17460441.1.7.635] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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41
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Ginj M, Zhang H, Waser B, Cescato R, Wild D, Wang X, Erchegyi J, Rivier J, Mäcke HR, Reubi JC. Radiolabeled somatostatin receptor antagonists are preferable to agonists for in vivo peptide receptor targeting of tumors. Proc Natl Acad Sci U S A 2006; 103:16436-41. [PMID: 17056720 PMCID: PMC1618814 DOI: 10.1073/pnas.0607761103] [Citation(s) in RCA: 344] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Targeting neuroendocrine tumors expressing somatostatin receptor subtypes (sst) with radiolabeled somatostatin agonists is an established diagnostic and therapeutic approach in oncology. While agonists readily internalize into tumor cells, permitting accumulation of radioactivity, radiolabeled antagonists do not, and they have not been considered for tumor targeting. The macrocyclic chelator 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) was coupled to two potent somatostatin receptor-selective peptide antagonists [NH(2)-CO-c(DCys-Phe-Tyr-DAgl(8)(Me,2-naphthoyl)-Lys-Thr-Phe-Cys)-OH (sst(3)-ODN-8) and a sst(2)-selective antagonist (sst(2)-ANT)], for labeling with (111/nat)In. (111/nat)In-DOTA-sst(3)-ODN-8 and (111/nat)In-DOTA-[4-NO(2)-Phe-c(DCys-Tyr-DTrp-Lys-Thr-Cys)-DTyr-NH(2)] ((111/nat)In-DOTA-sst(2)-ANT) showed high sst(3)- and sst(2)-binding affinity, respectively. They did not trigger sst(3) or sst(2) internalization but prevented agonist-stimulated internalization. (111)In-DOTA-sst(3)-ODN-8 and (111)In-DOTA-sst(2)-ANT were injected intravenously into mice bearing sst(3)- and sst(2)-expressing tumors, and their biodistribution was monitored. In the sst(3)-expressing tumors, strong accumulation of (111)In-DOTA-sst(3)-ODN-8 was observed, peaking at 1 h with 60% injected radioactivity per gram of tissue and remaining at a high level for >72 h. Excess of sst(3)-ODN-8 blocked uptake. As a control, the potent agonist (111)In-DOTA-[1-Nal(3)]-octreotide, with strong sst(3)-binding and internalization properties showed a much lower and shorter-lasting uptake in sst(3)-expressing tumors. Similarly, (111)In-DOTA-sst(2)-ANT was injected into mice bearing sst(2)-expressing tumors. Tumor uptake was considerably higher than with the highly potent sst(2)-selective agonist (111)In-diethylenetriaminepentaacetic acid-[Tyr(3),Thr(8)]-octreotide ((111)In-DTPA-TATE). Scatchard plots showed that antagonists labeled many more sites than agonists. Somatostatin antagonist radiotracers therefore are preferable over agonists for the in vivo targeting of sst(3)- or sst(2)-expressing tumors. Antagonist radioligands for other peptide receptors need to be evaluated in nuclear oncology as a result of this paradigm shift.
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Affiliation(s)
- Mihaela Ginj
- *Division of Radiological Chemistry, Institute of Nuclear Medicine, Department of Radiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland
| | - Hanwen Zhang
- *Division of Radiological Chemistry, Institute of Nuclear Medicine, Department of Radiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland
| | - Beatrice Waser
- Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, Murtenstrasse 31, CH-3010 Berne, Switzerland; and
| | - Renzo Cescato
- Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, Murtenstrasse 31, CH-3010 Berne, Switzerland; and
| | - Damian Wild
- *Division of Radiological Chemistry, Institute of Nuclear Medicine, Department of Radiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland
| | - Xuejuan Wang
- *Division of Radiological Chemistry, Institute of Nuclear Medicine, Department of Radiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland
| | - Judit Erchegyi
- Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037
| | - Jean Rivier
- Clayton Foundation Laboratories for Peptide Biology, The Salk Institute, 10010 North Torrey Pines Road, La Jolla, CA 92037
| | - Helmut R. Mäcke
- *Division of Radiological Chemistry, Institute of Nuclear Medicine, Department of Radiology, University Hospital Basel, Petersgraben 4, CH-4031 Basel, Switzerland
| | - Jean Claude Reubi
- Division of Cell Biology and Experimental Cancer Research, Institute of Pathology, University of Berne, Murtenstrasse 31, CH-3010 Berne, Switzerland; and
- To whom correspondence should be addressed. E-mail:
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Eva C, Serra M, Mele P, Panzica G, Oberto A. Physiology and gene regulation of the brain NPY Y1 receptor. Front Neuroendocrinol 2006; 27:308-39. [PMID: 16989896 DOI: 10.1016/j.yfrne.2006.07.002] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2005] [Revised: 07/18/2006] [Accepted: 07/25/2006] [Indexed: 10/24/2022]
Abstract
Neuropeptide Y (NPY) is one of the most prominent and abundant neuropeptides in the mammalian brain where it interacts with a family of G-protein coupled receptors, including the Y(1) receptor subtype (Y(1)R). NPY-Y(1)R signalling plays a prominent role in the regulation of several behavioural and physiological functions including feeding behaviour and energy balance, sexual hormone secretion, stress response, emotional behaviour, neuronal excitability and ethanol drinking. Y(1)R expression is regulated by neuronal activity and peripheral hormones. The Y(1)R gene has been isolated from rodents and humans and it contains multiple regulatory elements that may participate in the regulation of its expression. Y(1)R expression in the hypothalamus is modulated by changes in energetic balance induced by a wide variety of conditions (fasting, pregnancy, hyperglycaemic challenge, hypophagia, diet induced obesity). Estrogens up-regulate responsiveness to NPY to stimulate preovulatory GnRH and gonadotropin surges by increasing Y(1)R gene expression both in the hypothalamus and the pituitary. Y(1)R expression is modulated by different kinds of brain insults, such as stress and seizure activity, and alteration in its expression may contribute to antidepressant action. Chronic modulation of GABA(A) receptor function by benzodiazepines or neuroactive steroids also affects Y(1)R expression in the amygdala, suggesting that a functional interaction between the GABA(A) receptor and Y(1)R mediated signalling may contribute to the regulation of emotional behaviour. In this paper, we review the state of the art concerning Y(1)R function and gene expression, including our personal contribution to many of the subjects mentioned above.
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Affiliation(s)
- Carola Eva
- Sezione di Farmacologia, Dipartimento di Anatomia, Farmacologia e Medicina Legale, Università di Torino, Italy; Centro Rita Levi Montalcini, Università di Torino, Italy.
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Feng Z, Dubyak GR, Lederman MM, Weinberg A. Cutting edge: human beta defensin 3--a novel antagonist of the HIV-1 coreceptor CXCR4. THE JOURNAL OF IMMUNOLOGY 2006; 177:782-6. [PMID: 16818731 DOI: 10.4049/jimmunol.177.2.782] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previously, we showed that human epithelial cell-derived beta-defensins (hBD)-2 and -3 block HIV-1 replication via a direct interaction with virions and through modulation of the CXCR4 coreceptor on immunocompetent cells. In the present study, we show that hBD-3 promotes directly the internalization of CXCR4 yet does not induce calcium flux, ERK (ERK-1/2) phosphorylation, or chemotaxis. hBD-3 competes with stromal-derived factor 1 (SDF-1), the natural ligand for CXCR4, for cellular binding and blocks SDF-1-induced calcium flux, ERK-1/2 phosphorylation, and chemotaxis, without effects on other G protein-coupled receptors. The novel activity of this endogenous CXCR4 antagonist may provide a new strategy for HIV therapies or immunomodulation. Moreover, since the SDF-1/CXCR4 axis plays an important role in hemopoiesis, neurogenesis, cardiogenesis, and angiogenesis, endogenous agents such as hBD-3 or its derivatives offer a new paradigm in immunoregulatory therapeutics and provide the opportunity to enhance future drug design.
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Affiliation(s)
- Zhimin Feng
- Department of Biological Sciences, Case School of Dental Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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44
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Tough IR, Holliday ND, Cox HM. Y(4) receptors mediate the inhibitory responses of pancreatic polypeptide in human and mouse colon mucosa. J Pharmacol Exp Ther 2006; 319:20-30. [PMID: 16807358 DOI: 10.1124/jpet.106.106500] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The antisecretory effects of several Y agonists, including pancreatic polypeptide (PP), indicate the presence of Y(1), Y(2), and Y(4) receptors in mouse and human (h) colon mucosae. Here, we used preparations from human and from wild-type (WT), Y(4), and Y(1) receptor knockout ((-/-)) mice, alongside Y(4) receptor-transfected cells to define the relative functional contribution of the Y(4) receptor. First, rat (r) PP antisecretory responses were lost in murine Y(4)(-/-) preparations, but hPP and Pro(34) peptide YY (PYY) costimulated Y(4) and Y(1) receptors in WT mucosa. The Y(1) antagonist/Y(4) agonist GR231118 [(Ile,Glu,Pro,Dpr,Tyr,Arg,Leu,Arg,Try-NH(2))-2-cyclic(2,4'),(2',4)-diamide] elicited small Y(4)-mediated antisecretory responses in human tissues pretreated with the Y(1) antagonist, BIBO3304 [(R)-N-[[4-(aminocarbonylaminomethyl)-phenyl]methyl]-N(2)-(diphenylacetyl)-argininamide trifluoroacetate)], and attenuated Y(4)-mediated hPP responses in mouse and human mucosa. GR231118 and rPP were also antisecretory in hY(4)-transfected epithelial monolayers but were partial agonists compared with hPP at this receptor. In Y(4)-transfected human embryonic kidney (HEK) 293 cells, Y(4) ligands displaced [(125)I]hPP binding with orders of affinity (pK(i)) at human (hPP = rPP > GR231118 > Pro(34)PYY = PYY) and mouse (rPP = hPP > GR231118 > Pro(34)PYY > PYY) Y(4) receptors. GR231118- and rPP-stimulated guanosine 5'-3-O-(thio)triphosphate binding through hY(4) receptors with significantly lower efficacy than hPP. GR231118 marginally increased basal but abolished further PP-induced hY(4) internalization to recycling (transferrin-labeled) pathways in HEK293 cells. Taken together, these findings show that Y(4) receptors play a definitive role in attenuating colonic anion transport and may be useful targets for novel antidiarrheal agents due to their limited peripheral expression.
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Affiliation(s)
- Iain R Tough
- Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London SE1 1UL, UK
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45
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Dumont Y, Quirion R. An overview of neuropeptide Y: pharmacology to molecular biology and receptor localization. EXS 2006:7-33. [PMID: 16382995 DOI: 10.1007/3-7643-7417-9_2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- Yvan Dumont
- Douglas Hospital Research Centre, Department of Psychiatry, McGill University, 6875 Boul. LaSalle, Montreal, QC H4H 1R3, Canada.
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Dumont Y, Gaudreau P, Mazzuferi M, Langlois D, Chabot JG, Fournier A, Simonato M, Quirion R. BODIPY-conjugated neuropeptide Y ligands: new fluorescent tools to tag Y1, Y2, Y4 and Y5 receptor subtypes. Br J Pharmacol 2005; 146:1069-81. [PMID: 16231000 PMCID: PMC1751241 DOI: 10.1038/sj.bjp.0706425] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2005] [Revised: 09/12/2005] [Accepted: 09/21/2005] [Indexed: 12/26/2022] Open
Abstract
N-terminal labelled fluorescent BODIPY-NPY peptide analogues were tested in Y1, Y2, Y4 and Y5 receptor-binding assays performed in rat brain membrane preparations and HEK293 cells expressing the rat Y1, Y2, Y4 and Y5 receptors. BODIPY TMR/FL-[Leu31, Pro34]NPY/PYY were able to compete for specific [125][Leu31, Pro34]PYY-binding sites with an affinity similar to that observed for the native peptide at the Y1 (Ki=1-6 nM), Y2 (Ki>1000 nM), Y4 (Ki=10 nM) and Y5 (Ki=1-4 nM) receptor subtypes. BODIPY FL-PYY(3-36) was able to compete for specific Y2 (Ki=10 nM) and Y5 (Ki=30 nM) binding sites, but had almost no affinity in Y1 and Y4 assays. BODIPY FL-hPP was able to compete with high affinity (Ki; 1 and 15 nM) only in Y4 and Y5 receptor-binding assays. BODIPY TMR-[cPP(1-7), NPY(19-23), Ala31, Aib32, Gln34]hPP and BODIPY TMR-[hPP(1-17), Ala31, Aib32]NPY were potent competitors only on specific Y5-binding sites (Ki=0.1-0.6 nM). As expected, these fluorescent peptides inhibited forskolin-induced cAMP accumulation, demonstrating that they retained their agonist properties. When tested in confocal microscopy imaging, fluorescent Y1 and Y5 agonists internalized in a time-dependent manner in Y1 and Y5 transfected cells, respectively. These results demonstrate that BODIPY-conjugated NPY analogues retain their selectivity, affinity and agonist properties for the Y1, Y2, Y4 and Y5 receptor subtypes, respectively. Thus, they represent novel tools to study and visualize NPY receptors in living cells.
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Affiliation(s)
- Yvan Dumont
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal (Verdun), QC, Canada H4H 1R3
| | - Pierrette Gaudreau
- Laboratory of Neuroendocrinology of Aging, Centre hospitalier de l'Université de Montréal Research Center, Notre-Dame Hospital and Department of Medicine, University of Montreal, Montreal, QC, Canada H2L 4M1
| | - Manuela Mazzuferi
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal (Verdun), QC, Canada H4H 1R3
- Department of Clinical and Experimental Medicine (Section of Pharmacology) and Neuroscience Center, University of Ferrara, 44100 Ferrara, Italy
| | - Daniel Langlois
- Laboratory of Neuroendocrinology of Aging, Centre hospitalier de l'Université de Montréal Research Center, Notre-Dame Hospital and Department of Medicine, University of Montreal, Montreal, QC, Canada H2L 4M1
| | - Jean-Guy Chabot
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal (Verdun), QC, Canada H4H 1R3
| | - Alain Fournier
- Institut national de la recherche scientifique-Institut Armand-Frappier, Université du Québec, Montréal, QC, Canada H9R 1G6
| | - Michele Simonato
- Department of Clinical and Experimental Medicine (Section of Pharmacology) and Neuroscience Center, University of Ferrara, 44100 Ferrara, Italy
| | - Rémi Quirion
- Department of Psychiatry, Douglas Hospital Research Centre, McGill University, Montreal (Verdun), QC, Canada H4H 1R3
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Parker MS, Sah R, Sheriff S, Balasubramaniam A, Parker SL. Internalization of cloned pancreatic polypeptide receptors is accelerated by all types of Y4 agonists. ACTA ACUST UNITED AC 2005; 132:91-101. [PMID: 16213038 DOI: 10.1016/j.regpep.2005.09.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2005] [Accepted: 09/08/2005] [Indexed: 11/18/2022]
Abstract
Internalization of cloned rat or human Y4 receptors expressed in Chinese hamster ovary (CHO) cells increased with concentration of all types of Y4 agonists, including human and rat pancreatic polypeptides, the Y1 receptor group co-agonists possessing C-terminal TRPRY.NH2 pentapeptide, and a C-terminally amidated dimeric nonapeptide related to neuropeptide Y, GR231118. These peptides also inhibited forskolin-stimulated adenylyl cyclase activity in Y4 receptor-expressing cells, and stimulated the binding of 35S-labeled GTP-gamma-S to pertussis toxin-sensitive G-proteins in particulates from these cells. Peptide VD-11 (differing from GR231118 only by C-terminal oxymethylation) acted as a competitive antagonist in all of the above processes. Agonist-induced stimulation of the Y4 receptor internalization persisted in the presence of allosteric inhibitors of hPP binding, N5-substituted amilorides, which also were relatively little active in G-protein stimulation and cyclase inhibition by Y4 agonists. Acceleration of Y4 receptor internalization by agonists apparently is related to relaxation of allosteric constraints to ligand attachment and sequestration of the receptor-ligand complex.
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Affiliation(s)
- M S Parker
- Department of Microbiology and Molecular Cell Sciences, University of Memphis, Memphis, TN 38152, USA
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Thankachan S, Rusak B. Juxtacellular recording/labeling analysis of physiological and anatomical characteristics of rat intergeniculate leaflet neurons. J Neurosci 2005; 25:9195-204. [PMID: 16207879 PMCID: PMC6725760 DOI: 10.1523/jneurosci.2672-05.2005] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The thalamic intergeniculate leaflet (IGL) is involved in mediating effects of both photic and nonphotic stimuli on mammalian circadian rhythms. IGL neurons containing neuropeptide Y (NPY) have been implicated in mediating nonphotic effects, but little is known about those involved in photic entrainment. We used juxtacellular recording/labeling in rats to characterize both photic responses and neurochemical phenotypes of neurons in the lateral geniculate area, focusing on the IGL and ventral lateral geniculate (VLG). Single neurons were recorded to characterize photic responsiveness and were labeled with Neurobiotin (Nb); tissue was stained for Nb, NPY, and in some cases for orexin A. Three classes of neurons were identified in the IGL/VLG. Type I neurons lacked NPY and showed sustained activations during retinal illumination and moderate firing rates in darkness. Type II neurons contained large amounts of NPY throughout the soma and showed varied responses to illumination: suppression, complex responses, or no response. Type III neurons had patches of NPY both on the external soma surface and within the soma, apparently representing internalization of NPY. Type III neurons resembled type I cells in their sustained activation by illumination but were virtually silent during the intervening dark period. These neurons appear to receive NPY input, presumably from other IGL cells, which may suppress their activity during darkness. These results demonstrate the presence of several classes of neurons in the IGL defined by their functional and anatomical features and reinforce the role of the IGL/VLG complex in integrating photic and nonphotic inputs to the circadian system.
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Affiliation(s)
- Stephen Thankachan
- Department of Psychology, Dalhousie University, Halifax, Nova Scotia, B3H 4J1, Canada
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Viso A, Fernández de la Pradilla R, García A, Flores A. α,β-Diamino Acids: Biological Significance and Synthetic Approaches. Chem Rev 2005; 105:3167-96. [PMID: 16092828 DOI: 10.1021/cr0406561] [Citation(s) in RCA: 239] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Alma Viso
- Instituto de Química Orgánica, CSIC, Juan de la Cierva 3, E-28006 Madrid, Spain.
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Liu Q, Cescato R, Dewi DA, Rivier J, Reubi JC, Schonbrunn A. Receptor Signaling and Endocytosis Are Differentially Regulated by Somatostatin Analogs. Mol Pharmacol 2005; 68:90-101. [PMID: 15855408 DOI: 10.1124/mol.105.011767] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Upon hormone stimulation, the sst2 somatostatin receptor couples to adenylyl cyclase through G(i/o) proteins and undergoes rapid endocytosis via clathrin-coated pits. In this study, we determined the relationship between the ability of ligands to induce sst2 receptor internalization and inhibit adenylyl cyclase. Immunocytochemical studies demonstrated that peptide agonists [such as somatostatin-14, cortistatin-17, octreotide, vapreotide, KE108 (Tyr0-cyclo[d-diaminobutyric acid-Arg-Phe-Phe-d-Trp-Lys-Thr-Phe]), and SOM230 (cyclo[diaminoethylcarbamoyl-hydroxyproline-phenylglycine-d-Trp-Lys-(4-O-benzyl)-l-Tyr-Phe])] and nonpeptide agonists (such as L-779,976), stimulated the rapid endocytosis of sst2 receptors in human embryonic kidney 293 and CHO-K1 cells. In contrast, two antagonists did not induce receptor endocytosis by themselves and completely blocked agonist stimulation. Using a quantitative enzyme-linked immunosorbent assay to measure sst2 receptor sequestration, we found that peptide agonists varied by more than 100-fold in their potencies but exhibited the same efficacy as somatostatin14. In contrast, L-779,976 did not induce maximal receptor internalization. It is interesting that although betaarrestin-2 was recruited to cell surface sst2 receptors after stimulation with either somatostatin14 or L-779,976, the betaarrestin-receptor complex dissociated earlier in the endocytic pathway with the nonpeptide ligand. Although all agonists, including L-779,976, produced the same maximal inhibition of cyclic AMP, the potency ratio for inhibition of cyclic AMP and stimulation of receptor endocytosis varied by 15-fold. In general, native peptides showed similar potencies for cyclic AMP inhibition and receptor endocytosis, whereas short therapeutic analogs were substantially more potent at inhibiting cyclic AMP synthesis. These results demonstrate that the activity of somatostatin analogs to regulate receptor endocytosis and signaling are not tightly linked and provide compelling evidence for the induction of agonist specific states of the sst2 receptor.
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Affiliation(s)
- Qisheng Liu
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center-Houston, TX 77225, USA
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