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Bi M, Wang X, Wang J, Xu J, Sun W, Adediwura VA, Miao Y, Cheng Y, Ye L. Structure and function of an intermediate GPCR-Gαβγ complex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.02.587841. [PMID: 38617296 PMCID: PMC11014534 DOI: 10.1101/2024.04.02.587841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Unraveling the signaling roles of intermediate complexes is pivotal for G protein-coupled receptor (GPCR) drug development. Despite hundreds of GPCR-Gαβγ structures, these snapshots primarily capture the fully activated end-state complex. Consequently, a comprehensive understanding of the conformational transitions during GPCR activation and the roles of intermediate GPCR-G protein complexes in signaling remain elusive. Guided by a conformational landscape profiled by 19 F quantitative NMR ( 19 F-qNMR) and Molecular Dynamics (MD) simulations, we resolved the structure of an unliganded GPCR-G protein intermediate complex by blocking its transition to the fully activated end-state complex. More importantly, we presented direct evidence that the intermediate GPCR-Gαsβγ complex initiates a rate-limited nucleotide exchange without progressing to the fully activated end-state complex, thereby bridging a significant gap in our understanding the complexity of GPCR signaling. Understanding the roles of individual conformational states and their complexes in signaling efficacy and bias will help us to design drugs that discriminately target a disease-related conformation.
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2
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Arman S, Tilley RD, Gooding JJ. A review of electrochemical impedance as a tool for examining cell biology and subcellular mechanisms: merits, limits, and future prospects. Analyst 2024; 149:269-289. [PMID: 38015145 DOI: 10.1039/d3an01423a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Herein the development of cellular impedance biosensors, electrochemical impedance spectroscopy, and the general principles and terms associated with the cell-electrode interface is reviewed. This family of techniques provides quantitative and sensitive information into cell responses to stimuli in real-time with high temporal resolution. The applications of cell-based impedance biosensors as a readout in cell biology is illustrated with a diverse range of examples. The current state of the field, its limitations, the possible available solutions, and the potential benefits of developing biosensors are discussed.
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Affiliation(s)
- Seyedyousef Arman
- School of Chemistry, The University of New South Wales, Sydney, New South Wales 2052, Australia.
- Australia Centre for Nanomedicine, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Richard D Tilley
- School of Chemistry, The University of New South Wales, Sydney, New South Wales 2052, Australia.
- Electron Microscope Unit, Mark Wainwright Analytical Centre, The University of New South Wales, Sydney, New South Wales 2052, Australia
| | - J Justin Gooding
- School of Chemistry, The University of New South Wales, Sydney, New South Wales 2052, Australia.
- Australia Centre for Nanomedicine, The University of New South Wales, Sydney, New South Wales 2052, Australia
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3
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Sadee W. Ligand-Free Signaling of G-Protein-Coupled Receptors: Physiology, Pharmacology, and Genetics. Molecules 2023; 28:6375. [PMID: 37687205 PMCID: PMC10489045 DOI: 10.3390/molecules28176375] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 08/28/2023] [Accepted: 08/30/2023] [Indexed: 09/10/2023] Open
Abstract
G-protein-coupled receptors (GPCRs) are ubiquitous sensors and regulators of cellular functions. Each GPCR exists in complex aggregates with multiple resting and active conformations. Designed to detect weak stimuli, GPCRs can also activate spontaneously, resulting in basal ligand-free signaling. Agonists trigger a cascade of events leading to an activated agonist-receptor G-protein complex with high agonist affinity. However, the ensuing signaling process can further remodel the receptor complex to reduce agonist affinity, causing rapid ligand dissociation. The acutely activated ligand-free receptor can continue signaling, as proposed for rhodopsin and μ opioid receptors, resulting in robust receptor activation at low agonist occupancy with enhanced agonist potency. Continued receptor stimulation can further modify the receptor complex, regulating sustained ligand-free signaling-proposed to play a role in opioid dependence. Basal, acutely agonist-triggered, and sustained elevated ligand-free signaling could each have distinct functions, reflecting multi-state conformations of GPCRs. This review addresses basal and stimulus-activated ligand-free signaling, its regulation, genetic factors, and pharmacological implications, focusing on opioid and serotonin receptors, and the growth hormone secretagogue receptor (GHSR). The hypothesis is proposed that ligand-free signaling of 5-HT2A receptors mediate therapeutic effects of psychedelic drugs. Research avenues are suggested to close the gaps in our knowledge of ligand-free GPCR signaling.
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Affiliation(s)
- Wolfgang Sadee
- Cancer Biology and Genetics, College of Medicine, The Ohio State University, Columbus, OH 43210, USA;
- Bioengineering and Therapeutic Sciences, University of California, San Francisco, CA 94158, USA
- Aether Therapeutics Inc., Austin, TX 78756, USA
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4
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Courault P, Lancelot S, Costes N, Colom M, Le Bars D, Redoute J, Gobert F, Dailler F, Isal S, Iecker T, Newman-Tancredi A, Merida I, Zimmer L. [ 18F]F13640: a selective agonist PET radiopharmaceutical for imaging functional 5-HT 1A receptors in humans. Eur J Nucl Med Mol Imaging 2023; 50:1651-1664. [PMID: 36656363 PMCID: PMC10119077 DOI: 10.1007/s00259-022-06103-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 12/27/2022] [Indexed: 01/20/2023]
Abstract
PURPOSE F13640 (a.k.a. befiradol, NLX-112) is a highly selective 5-HT1A receptor ligand that was selected as a PET radiopharmaceutical-candidate based on animal studies. Due to its high efficacy agonist properties, [18F]F13640 binds preferentially to functional 5-HT1A receptors, which are coupled to intracellular G-proteins. Here, we characterize brain labeling of 5-HT1A receptors by [18F]F13640 in humans and describe a simplified model for its quantification. METHODS PET/CT and PET-MRI scans were conducted in a total of 13 healthy male volunteers (29 ± 9 years old), with arterial input functions (AIF) (n = 9) and test-retest protocol (n = 8). Several kinetic models were compared (one tissue compartment model, two-tissue compartment model, and Logan); two models with reference region were also evaluated: simplified reference tissue model (SRTM) and the logan reference model (LREF). RESULTS [18F]F13640 showed high uptake values in raphe nuclei and cortical regions. SRTM and LREF models showed a very high correlation with kinetic models using AIF. As concerns test-retest parameters and the prolonged binding kinetics of [18F]F13640, better reproducibility, and reliability were found with the LREF method. Cerebellum white matter and frontal lobe white matter stand out as suitable reference regions. CONCLUSION The favorable brain labeling and kinetic profile of [18F]F13640, its high receptor specificity and its high efficacy agonist properties open new perspectives for studying functionally active 5-HT1A receptors, unlike previous radiopharmaceuticals that act as antagonists. [18F]F13640's kinetic properties allow injection outside of the PET scanner with delayed acquisitions, facilitating the design of innovative longitudinal protocols in neurology and psychiatry. TRIAL REGISTRATION Trial Registration EudraCT 2017-002,722-21.
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Affiliation(s)
- Pierre Courault
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France.,Hospices Civils de Lyon (HCL), Lyon, France
| | - Sophie Lancelot
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France.,Hospices Civils de Lyon (HCL), Lyon, France.,CERMEP, Bron, France
| | - Nicolas Costes
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France.,CERMEP, Bron, France
| | | | - Didier Le Bars
- Hospices Civils de Lyon (HCL), Lyon, France.,CERMEP, Bron, France
| | | | - Florent Gobert
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France.,Hospices Civils de Lyon (HCL), Lyon, France
| | | | - Sibel Isal
- Hospices Civils de Lyon (HCL), Lyon, France
| | | | | | | | - Luc Zimmer
- Université Claude Bernard Lyon 1, CNRS, INSERM, Lyon Neuroscience Research Center, Lyon, France. .,Hospices Civils de Lyon (HCL), Lyon, France. .,CERMEP, Bron, France.
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5
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Ligand-Free Signaling of G-Protein-Coupled Receptors: Relevance to μ Opioid Receptors in Analgesia and Addiction. Molecules 2022; 27:molecules27185826. [PMID: 36144565 PMCID: PMC9503102 DOI: 10.3390/molecules27185826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/04/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
Numerous G-protein-coupled receptors (GPCRs) display ligand-free basal signaling with potential physiological functions, a target in drug development. As an example, the μ opioid receptor (MOR) signals in ligand-free form (MOR-μ*), influencing opioid responses. In addition, agonists bind to MOR but can dissociate upon MOR activation, with ligand-free MOR-μ* carrying out signaling. Opioid pain therapy is effective but incurs adverse effects (ADRs) and risk of opioid use disorder (OUD). Sustained opioid agonist exposure increases persistent basal MOR-μ* activity, which could be a driving force for OUD and ADRs. Antagonists competitively prevent resting MOR (MOR-μ) activation to MOR-μ*, while common antagonists, such as naloxone and naltrexone, also bind to and block ligand-free MOR-μ*, acting as potent inverse agonists. A neutral antagonist, 6β-naltrexol (6BN), binds to but does not block MOR-μ*, preventing MOR-μ activation only competitively with reduced potency. We hypothesize that 6BN gradually accelerates MOR-μ* reversal to resting-state MOR-μ. Thus, 6BN potently prevents opioid dependence in rodents, at doses well below those blocking antinociception or causing withdrawal. Acting as a ‘retrograde addiction modulator’, 6BN could represent a novel class of therapeutics for OUD. Further studies need to address regulation of MOR-μ* and, more broadly, the physiological and pharmacological significance of ligand-free signaling in GPCRs.
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Newman-Tancredi A, Depoortère RY, Kleven MS, Kołaczkowski M, Zimmer L. Translating biased agonists from molecules to medications: Serotonin 5-HT 1A receptor functional selectivity for CNS disorders. Pharmacol Ther 2021; 229:107937. [PMID: 34174274 DOI: 10.1016/j.pharmthera.2021.107937] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/01/2021] [Accepted: 06/17/2021] [Indexed: 12/18/2022]
Abstract
Biased agonism (or "functional selectivity") at G-protein-coupled receptors has attracted rapidly increasing interest as a means to improve discovery of more efficacious and safer pharmacotherapeutics. However, most studies are limited to in vitro tests of cellular signaling and few biased agonists have progressed to in vivo testing. As concerns 5-HT1A receptors, which exert a major control of serotonergic signaling in diverse CNS regions, study of biased agonism has previously been limited by the poor target selectivity and/or partial agonism of classically available ligands. However, a new generation of highly selective, efficacious and druggable agonists has advanced the study of biased agonism at this receptor and created new therapeutic opportunities. These novel agonists show differential properties for G-protein signaling, cellular signaling (particularly pERK), electrophysiological effects, neurotransmitter release, neuroimaging by PET and pharmacoMRI, and behavioral tests of mood, motor activity and side effects. Overall, NLX-101 (a.k.a. F15599) exhibits preferential activation of cortical and brain stem 5-HT1A receptors, whereas NLX-112 (a.k.a. befiradol or F13640) shows prominent activation of 5-HT1A autoreceptors in Raphe nuclei and in regions associated with motor control. Accordingly, NLX-101 is potently active in rodent models of depression and respiratory control, whereas NLX-112 shows promising activity in models of Parkinson's disease across several species - rat, marmoset and macaque. Moreover, NLX-112 has also been labeled with 18F to produce the first agonist PET radiopharmaceutical (known as [18F]-F13640) for investigation of the active state of 5-HT1A receptors in rodent, primate and human. The structure-functional activity relationships of biased agonists have been investigated by receptor modeling and novel compounds have been identified which exhibit increased affinity at 5-HT1A receptors and new profiles of cellular signaling bias, notably for β-arrestin recruitment versus pERK. Taken together, the data suggest that 5-HT1A receptor biased agonists constitute potentially superior pharmacological agents for treatment of CNS disorders involving serotonergic mechanisms.
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Affiliation(s)
| | | | | | | | - Luc Zimmer
- Université Claude Bernard Lyon1, Lyon, France; Hospices Civils de Lyon, Lyon, France; Lyon Neuroscience Research Center, CNRS-INSERM, France
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7
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Yang LK, Hou ZS, Tao YX. Biased signaling in naturally occurring mutations of G protein-coupled receptors associated with diverse human diseases. Biochim Biophys Acta Mol Basis Dis 2021; 1867:165973. [PMID: 32949766 PMCID: PMC7722056 DOI: 10.1016/j.bbadis.2020.165973] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/07/2020] [Accepted: 09/14/2020] [Indexed: 12/15/2022]
Abstract
G protein-coupled receptors (GPCRs) play critical roles in transmitting a variety of extracellular signals into the cells and regulate diverse physiological functions. Naturally occurring mutations that result in dysfunctions of GPCRs have been known as the causes of numerous diseases. Significant progresses have been made in elucidating the pathophysiology of diseases caused by mutations. The multiple intracellular signaling pathways, such as G protein-dependent and β-arrestin-dependent signaling, in conjunction with recent advances on biased agonism, have broadened the view on the molecular mechanism of disease pathogenesis. This review aims to briefly discuss biased agonism of GPCRs (biased ligands and biased receptors), summarize the naturally occurring GPCR mutations that cause biased signaling, and propose the potential pathophysiological relevance of biased mutant GPCRs associated with various endocrine diseases.
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Affiliation(s)
- Li-Kun Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Zhi-Shuai Hou
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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8
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Dynamic imine bond based chitosan smart hydrogel with magnified mechanical strength for controlled drug delivery. Int J Biol Macromol 2020; 160:489-495. [DOI: 10.1016/j.ijbiomac.2020.05.221] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 05/11/2020] [Accepted: 05/26/2020] [Indexed: 11/22/2022]
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9
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Pinteala M, Abadie MJM, Rusu RD. Smart Supra- and Macro-Molecular Tools for Biomedical Applications. MATERIALS 2020; 13:ma13153343. [PMID: 32727155 PMCID: PMC7435709 DOI: 10.3390/ma13153343] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/22/2020] [Accepted: 07/24/2020] [Indexed: 12/28/2022]
Abstract
Stimuli-responsive, “smart” polymeric materials used in the biomedical field function in a bio-mimicking manner by providing a non-linear response to triggers coming from a physiological microenvironment or other external source. They are built based on various chemical, physical, and biological tools that enable pH and/or temperature-stimulated changes in structural or physicochemical attributes, like shape, volume, solubility, supramolecular arrangement, and others. This review touches on some particular developments on the topic of stimuli-sensitive molecular tools for biomedical applications. Design and mechanistic details are provided concerning the smart synthetic instruments that are employed to prepare supra- and macro-molecular architectures with specific responses to external stimuli. Five major themes are approached: (i) temperature- and pH-responsive systems for controlled drug delivery; (ii) glycodynameric hydrogels for drug delivery; (iii) polymeric non-viral vectors for gene delivery; (iv) metallic nanoconjugates for biomedical applications; and, (v) smart organic tools for biomedical imaging.
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Affiliation(s)
- Mariana Pinteala
- “Petru Poni” Institute of Macromolecular Chemistry, Romanian Academy, Grigore Ghica Voda Alley, 41A, 700487 Iasi, Romania; (M.P.); (M.J.M.A.)
| | - Marc J. M. Abadie
- “Petru Poni” Institute of Macromolecular Chemistry, Romanian Academy, Grigore Ghica Voda Alley, 41A, 700487 Iasi, Romania; (M.P.); (M.J.M.A.)
- Institute Charles Gerhardt Montpellier, Bat 15, CC 1052, University of Montpellier, 34095 Montpellier, France
| | - Radu D. Rusu
- “Petru Poni” Institute of Macromolecular Chemistry, Romanian Academy, Grigore Ghica Voda Alley, 41A, 700487 Iasi, Romania; (M.P.); (M.J.M.A.)
- Correspondence: ; Tel.: +40-232-217454
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10
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Franco R, Aguinaga D, Jiménez J, Lillo J, Martínez-Pinilla E, Navarro G. Biased receptor functionality versus biased agonism in G-protein-coupled receptors. Biomol Concepts 2018; 9:143-154. [PMID: 30864350 DOI: 10.1515/bmc-2018-0013] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 11/02/2018] [Indexed: 02/06/2023] Open
Abstract
Functional selectivity is a property of G-protein-coupled receptors (GPCRs) by which activation by different agonists leads to different signal transduction mechanisms. This phenomenon is also known as biased agonism and has attracted the interest of drug discovery programs in both academy and industry. This relatively recent concept has raised concerns as to the validity and real translational value of the results showing bias; firstly biased agonism may vary significantly depending on the cell type and the experimental constraints, secondly the conformational landscape that leads to biased agonism has not been defined. Remarkably, GPCRs may lead to differential signaling even when a single agonist is used. Here we present a concept that constitutes a biochemical property of GPCRs that may be underscored just using one agonist, preferably the endogenous agonist. "Biased receptor functionality" is proposed to describe this effect with examples based on receptor heteromerization and alternative splicing. Examples of regulation of final agonist-induced outputs based on interaction with β-arrestins or calcium sensors are also provided. Each of the functional GPCR units (which are finite in number) has a specific conformation. Binding of agonist to a specific conformation, i.e. GPCR activation, is sensitive to the kinetics of the agonist-receptor interactions. All these players are involved in the contrasting outputs obtained when different agonists are assayed.
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Affiliation(s)
- Rafael Franco
- Molecular Neurobiology laboratory.Department of Biochemistry and Molecular Biomedicine, Biology School, University of Barcelona, Barcelona, Spain.,Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - David Aguinaga
- Molecular Neurobiology laboratory.Department of Biochemistry and Molecular Biomedicine, Biology School, University of Barcelona, Barcelona, Spain.,Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Jasmina Jiménez
- Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain
| | - Jaume Lillo
- Molecular Neurobiology laboratory.Department of Biochemistry and Molecular Biomedicine, Biology School, University of Barcelona, Barcelona, Spain
| | - Eva Martínez-Pinilla
- Departamento de Morfología y Biología Celular, Facultad de Medicina, Universidad de Oviedo, Asturias, Spain.,Instituto de Neurociencias del Principado de Asturias (INEUROPA), Asturias, Spain.,Instituto de Salud del Principado de Asturias (ISPA), Asturias, Spain
| | - Gemma Navarro
- Centro de Investigación en Red, Enfermedades Neurodegenerativas (CIBERNED), Instituto de Salud Carlos III, Madrid, Spain.,Department of Biochemistry and Physiology, Pharmacy and Food Science School, University of Barcelona, Barcelona Spain
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11
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Ho JH, Stahl EL, Schmid CL, Scarry SM, Aubé J, Bohn LM. G protein signaling-biased agonism at the κ-opioid receptor is maintained in striatal neurons. Sci Signal 2018; 11:11/542/eaar4309. [PMID: 30087177 DOI: 10.1126/scisignal.aar4309] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Biased agonists of G protein-coupled receptors may present a means to refine receptor signaling in a way that separates side effects from therapeutic properties. Several studies have shown that agonists that activate the κ-opioid receptor (KOR) in a manner that favors G protein coupling over β-arrestin2 recruitment in cell culture may represent a means to treat pain and itch while avoiding sedation and dysphoria. Although it is attractive to speculate that the bias between G protein signaling and β-arrestin2 recruitment is the reason for these divergent behaviors, little evidence has emerged to show that these signaling pathways diverge in the neuronal environment. We further explored the influence of cellular context on biased agonism at KOR ligand-directed signaling toward G protein pathways over β-arrestin-dependent pathways and found that this bias persists in striatal neurons. These findings advance our understanding of how a G protein-biased agonist signal differs between cell lines and primary neurons, demonstrate that measuring [35S]GTPγS binding and the regulation of adenylyl cyclase activity are not necessarily orthogonal assays in cell lines, and emphasize the contributions of the environment to assessing biased agonism.
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Affiliation(s)
- Jo-Hao Ho
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Edward L Stahl
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Cullen L Schmid
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA
| | - Sarah M Scarry
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Jeffrey Aubé
- UNC Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Laura M Bohn
- Departments of Molecular Medicine and Neuroscience, The Scripps Research Institute, Jupiter, FL 33458, USA.
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12
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Opioids: Modulators of angiogenesis in wound healing and cancer. Oncotarget 2018; 8:25783-25796. [PMID: 28445930 PMCID: PMC5421968 DOI: 10.18632/oncotarget.15419] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 02/07/2017] [Indexed: 12/12/2022] Open
Abstract
Opioids are potent drugs that are widely used to control wound or cancer pain. Increasing evidence suggest that opioids mediate clinically relevant effects that go beyond their classical role as analgesics. Of note, opioids appear to modulate angiogenesis - a process that is critical in wound healing and cancer progression. In this review, we focus on pro- and anti-angiogenic facets of opioids that arise from the activation of individual opioid receptors and the usage of individual concentrations or application routes. We overview the still incompletely elucidated mechanisms of these angiogenic opioid actions. Moreover, we describe plausible opioids effects, which - although not primarily studied in the context of vessel formation - may be related to the opioid-driven processes of angiogenesis. Finally we discuss the use of opioids as an innovative therapeutic avenue for the treatment of chronic wounds and cancer.
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13
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Granja-Galeano G, Zappia CD, Fabián L, Davio C, Shayo C, Fernández N, Monczor F. Effect of mutation of Phe 243 6.44 of the histamine H 2 receptor on cimetidine and ranitidine mechanism of action. Biochem Pharmacol 2017; 146:117-126. [DOI: 10.1016/j.bcp.2017.09.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 09/25/2017] [Indexed: 12/13/2022]
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14
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Leprince J, Bagnol D, Bureau R, Fukusumi S, Granata R, Hinuma S, Larhammar D, Primeaux S, Sopkova-de Oliveiras Santos J, Tsutsui K, Ukena K, Vaudry H. The Arg-Phe-amide peptide 26RFa/glutamine RF-amide peptide and its receptor: IUPHAR Review 24. Br J Pharmacol 2017; 174:3573-3607. [PMID: 28613414 DOI: 10.1111/bph.13907] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Revised: 05/30/2017] [Accepted: 06/05/2017] [Indexed: 12/21/2022] Open
Abstract
The RFamide neuropeptide 26RFa was first isolated from the brain of the European green frog on the basis of cross-reactivity with antibodies raised against bovine neuropeptide FF (NPFF). 26RFa and its N-terminally extended form glutamine RF-amide peptide (QRFP) have been identified as cognate ligands of the former orphan receptor GPR103, now renamed glutamine RF-amide peptide receptor (QRFP receptor). The 26RFa/QRFP precursor has been characterized in various mammalian and non-mammalian species. In the brain of mammals, including humans, 26RFa/QRFP mRNA is almost exclusively expressed in hypothalamic nuclei. The 26RFa/QRFP transcript is also present in various organs especially in endocrine glands. While humans express only one QRFP receptor, two isoforms are present in rodents. The QRFP receptor genes are widely expressed in the CNS and in peripheral tissues, notably in bone, heart, kidney, pancreas and testis. Structure-activity relationship studies have led to the identification of low MW peptidergic agonists and antagonists of QRFP receptor. Concurrently, several selective non-peptidic antagonists have been designed from high-throughput screening hit optimization. Consistent with the widespread distribution of QRFP receptor mRNA and 26RFa binding sites, 26RFa/QRFP exerts a large range of biological activities, notably in the control of energy homeostasis, bone formation and nociception that are mediated by QRFP receptor or NPFF2. The present report reviews the current knowledge concerning the 26RFa/QRFP-QRFP receptor system and discusses the potential use of selective QRFP receptor ligands for therapeutic applications.
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Affiliation(s)
- Jérôme Leprince
- INSERM U1239, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Normandy University, Rouen, France
| | - Didier Bagnol
- CNS Drug Discovery, Arena Pharmaceuticals Inc., San Diego, CA, USA
| | - Ronan Bureau
- Normandy Centre for Studies and Research on Medicines (CERMN), Normandy University, Caen, France
| | - Shoji Fukusumi
- International Institute for Integrative Sleep Medicine (WPI-IIIS), University of Tsukuba, Tsukuba, Ibaraki, Japan
| | - Riccarda Granata
- Laboratory of Molecular and Cellular Endocrinology, Division of Endocrinology, Diabetes and Metabolism, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Shuji Hinuma
- Department of Food and Nutrition, Faculty of Human Life Science, Senri Kinran University, Suita-City, Osaka, Japan
| | - Dan Larhammar
- Department of Neuroscience, Unit of Pharmacology, Uppsala University, Uppsala, Sweden
| | - Stefany Primeaux
- Department of Physiology, Joint Diabetes, Endocrinology & Metabolism Center, Louisiana State University Health Sciences Center, New Orleans, LA, USA
| | | | - Kazuyoshi Tsutsui
- Laboratory of Integrative Brain Sciences, Department of Biology, Waseda University, Center for Medical Life Science, Tokyo, Japan
| | - Kazuyoshi Ukena
- Section of Behavioral Sciences, Graduate School of Integrated Arts and Sciences, Hiroshima University, Higashi-Hiroshima, Japan
| | - Hubert Vaudry
- INSERM U1239, Laboratory of Neuronal and Neuroendocrine Differentiation and Communication, Normandy University, Rouen, France
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15
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Madariaga-Mazón A, Marmolejo-Valencia AF, Li Y, Toll L, Houghten RA, Martinez-Mayorga K. Mu-Opioid receptor biased ligands: A safer and painless discovery of analgesics? Drug Discov Today 2017; 22:1719-1729. [PMID: 28743488 DOI: 10.1016/j.drudis.2017.07.002] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 06/24/2017] [Accepted: 07/07/2017] [Indexed: 12/19/2022]
Abstract
Biased activation of G-protein-coupled receptors (GPCRs) is shifting drug discovery efforts and appears promising for the development of safer drugs. The most effective analgesics to treat acute pain are agonists of the μ opioid receptor (μ-OR), a member of the GPCR superfamily. However, the analgesic use of opioid drugs, such as morphine, is hindered by adverse effects. Only a few μ-OR agonists have been reported to selectively activate the Gi over β-arrestin signaling pathway, resulting in lower gastrointestinal dysfunction and respiratory suppression. Here, we discuss the strategies that led to the development of biased μ-OR agonists, and potential areas for improvement, with an emphasis on structural aspects of the ligand-receptor recognition process.
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Affiliation(s)
- Abraham Madariaga-Mazón
- Instituto de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, Mexico City 04510, Mexico
| | - Andrés F Marmolejo-Valencia
- Instituto de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, Mexico City 04510, Mexico
| | - Yangmei Li
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA
| | - Lawrence Toll
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA
| | - Richard A Houghten
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Pkwy, Port St. Lucie, FL 34987, USA
| | - Karina Martinez-Mayorga
- Instituto de Química, Universidad Nacional Autónoma de México, Av. Universidad 3000, Mexico City 04510, Mexico.
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16
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da Silva Junior ED, Sato M, Merlin J, Broxton N, Hutchinson DS, Ventura S, Evans BA, Summers RJ. Factors influencing biased agonism in recombinant cells expressing the human α 1A -adrenoceptor. Br J Pharmacol 2017; 174:2318-2333. [PMID: 28444738 DOI: 10.1111/bph.13837] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 04/06/2017] [Accepted: 04/12/2017] [Indexed: 12/12/2022] Open
Abstract
BACKGROUND AND PURPOSE Agonists acting at GPCRs promote biased signalling via Gα or Gβγ subunits, GPCR kinases and β-arrestins. Since the demonstration of biased agonism has implications for drug discovery, it is essential to consider confounding factors contributing to bias. We have examined bias at human α1A -adrenoceptors stably expressed at low levels in CHO-K1 cells, identifying off-target effects at endogenous receptors that contribute to ERK1/2 phosphorylation in response to the agonist oxymetazoline. EXPERIMENTAL APPROACH Intracellular Ca2+ mobilization was monitored in a Flexstation® using Fluo 4-AM. The accumulation of cAMP and ERK1/2 phosphorylation were measured using AlphaScreen® proximity assays, and mRNA expression was measured by RT-qPCR. Ligand bias was determined using the operational model of agonism. KEY RESULTS Noradrenaline, phenylephrine, methoxamine and A61603 increased Ca2+ mobilization, cAMP accumulation and ERK1/2 phosphorylation. However, oxymetazoline showed low efficacy for Ca+2 mobilization, no effect on cAMP generation and high efficacy for ERK1/2 phosphorylation. The apparent functional selectivity of oxymetazoline towards ERK1/2 was related to off-target effects at 5-HT1B receptors endogenously expressed in CHO-K1 cells. Phenylephrine and methoxamine showed genuine bias towards ERK1/2 phosphorylation compared to Ca2+ and cAMP pathways, whereas A61603 displayed bias towards cAMP accumulation compared to ERK1/2 phosphorylation. CONCLUSION AND IMPLICATIONS We have shown that while adrenergic agonists display bias at human α1A -adrenoceptors, the marked bias of oxymetazoline for ERK1/2 phosphorylation originates from off-target effects. Commonly used cell lines express a repertoire of endogenous GPCRs that may confound studies on biased agonism at recombinant receptors.
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Affiliation(s)
| | - Masaaki Sato
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Jon Merlin
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Natalie Broxton
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Dana S Hutchinson
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Sabatino Ventura
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Bronwyn A Evans
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Roger J Summers
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
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17
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Iftime MM, Morariu S, Marin L. Salicyl-imine-chitosan hydrogels: Supramolecular architecturing as a crosslinking method toward multifunctional hydrogels. Carbohydr Polym 2017; 165:39-50. [DOI: 10.1016/j.carbpol.2017.02.027] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 01/23/2017] [Accepted: 02/08/2017] [Indexed: 12/01/2022]
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18
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Yang LK, Tao YX. Biased signaling at neural melanocortin receptors in regulation of energy homeostasis. Biochim Biophys Acta Mol Basis Dis 2017; 1863:2486-2495. [PMID: 28433713 DOI: 10.1016/j.bbadis.2017.04.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 04/09/2017] [Accepted: 04/10/2017] [Indexed: 12/15/2022]
Abstract
The global prevalence of obesity highlights the importance of understanding on regulation of energy homeostasis. The central melanocortin system is an important intersection connecting the neural pathways controlling satiety and energy expenditure to regulate energy homeostasis by sensing and integrating the signals of external stimuli. In this system, neural melanocortin receptors (MCRs), melanocortin-3 and -4 receptors (MC3R and MC4R), play crucial roles in the regulation of energy homeostasis. Recently, multiple intracellular signaling pathways and biased signaling at neural MCRs have been discovered, providing new insights into neural MCR signaling. This review attempts to summarize biased signaling including biased receptor mutants (both naturally occurring and lab-generated) and biased ligands at neural MCRs, and to provide a better understanding of obesity pathogenesis and new therapeutic implications for obesity treatment.
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Affiliation(s)
- Li-Kun Yang
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States
| | - Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, AL 36849, United States.
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19
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Kendall DA, Yudowski GA. Cannabinoid Receptors in the Central Nervous System: Their Signaling and Roles in Disease. Front Cell Neurosci 2017; 10:294. [PMID: 28101004 PMCID: PMC5209363 DOI: 10.3389/fncel.2016.00294] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 12/08/2016] [Indexed: 11/15/2022] Open
Abstract
The identification and cloning of the two major cannabinoid (CB1 and CB2) receptors together with the discovery of their endogenous ligands in the late 80s and early 90s, resulted in a major effort aimed at understanding the mechanisms and physiological roles of the endocannabinoid system (ECS). Due to its expression and localization in the central nervous system (CNS), the CB1 receptor together with its endogenous ligands (endocannabinoids (eCB)) and the enzymes involved in their synthesis and degradation, has been implicated in multiple pathophysiological events ranging from memory deficits to neurodegenerative disorders among others. In this review, we will provide a general overview of the ECS with emphasis on the CB1 receptor in health and disease. We will describe our current understanding of the complex aspects of receptor signaling and trafficking, including the non-canonical signaling pathways such as those mediated by β-arrestins within the context of functional selectivity and ligand bias. Finally, we will highlight some of the disorders in which CB1 receptors have been implicated. Significant knowledge has been achieved over the last 30 years. However, much more research is still needed to fully understand the complex roles of the ECS, particularly in vivo and to unlock its true potential as a source of therapeutic targets.
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Affiliation(s)
- Debra A Kendall
- Department of Pharmaceutical Sciences, University of Connecticut Storrs, CT, USA
| | - Guillermo A Yudowski
- Department of Anatomy and Neurobiology, University of Puerto Rico, Medical Sciences CampusSan Juan, Puerto Rico; Institute of Neurobiology, University of Puerto RicoSan Juan, Puerto Rico
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20
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Vibrational resonance, allostery, and activation in rhodopsin-like G protein-coupled receptors. Sci Rep 2016; 6:37290. [PMID: 27849063 PMCID: PMC5110974 DOI: 10.1038/srep37290] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 10/28/2016] [Indexed: 12/13/2022] Open
Abstract
G protein-coupled receptors are a large family of membrane proteins activated by a variety of structurally diverse ligands making them highly adaptable signaling molecules. Despite recent advances in the structural biology of this protein family, the mechanism by which ligands induce allosteric changes in protein structure and dynamics for its signaling function remains a mystery. Here, we propose the use of terahertz spectroscopy combined with molecular dynamics simulation and protein evolutionary network modeling to address the mechanism of activation by directly probing the concerted fluctuations of retinal ligand and transmembrane helices in rhodopsin. This approach allows us to examine the role of conformational heterogeneity in the selection and stabilization of specific signaling pathways in the photo-activation of the receptor. We demonstrate that ligand-induced shifts in the conformational equilibrium prompt vibrational resonances in the protein structure that link the dynamics of conserved interactions with fluctuations of the active-state ligand. The connection of vibrational modes creates an allosteric association of coupled fluctuations that forms a coherent signaling pathway from the receptor ligand-binding pocket to the G-protein activation region. Our evolutionary analysis of rhodopsin-like GPCRs suggest that specific allosteric sites play a pivotal role in activating structural fluctuations that allosterically modulate functional signals.
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21
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Genua M, Ingangi V, Fonteyne P, Piontini A, Yousif AM, Merlino F, Grieco P, Malesci A, Carriero MV, Danese S. Treatment with a Urokinase Receptor-derived Cyclized Peptide Improves Experimental Colitis by Preventing Monocyte Recruitment and Macrophage Polarization. Inflamm Bowel Dis 2016; 22:2390-401. [PMID: 27537052 DOI: 10.1097/mib.0000000000000896] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
BACKGROUND Leukocyte migration across the blood barrier and into tissues represents a key process in the pathogenesis of inflammatory bowel diseases. The urokinase receptor (urokinase-type plasminogen activator receptor) is a master regulator of leukocyte recruitment. We recently found that cyclization of the urokinase-type plasminogen activator receptor-derived peptide Ser-Arg-Ser-Arg-Tyr [SRSRY] inhibits transendothelial migration of monocytes. Now, we have explored the effects of [SRSRY] administration during experimental colitis. METHODS The effects of [SRSRY] on cytokine profile, cytoskeletal organization, and cell migration were investigated using phorbol-12-myristate acetate-differentiated THP-1 cells exposed to polarizing stimuli. In vivo, [SRSRY] was intraperitoneally administered during dextran sodium sulfate- or 2,4,6-trinitrobenzene sulfonic acid-induced colitis in wild-type or urokinase-type plasminogen activator receptor knockout mice. Levels of pro-inflammatory cytokines and inflammatory monocytes in mucosal infiltrates were assessed by enzyme-linked immunosorbent assay and flow cytometry, respectively. RESULTS [SRSRY] prevents M0 to M1 transition and migration of M1 polarized macrophages. In vivo, [SRSRY] reduces intestinal inflammation diminishing body weight loss and disease activity index. These beneficial effects are accompanied by a reduction of interleukin 1β, interleukin 6, and tumor necrosis factor α, an increase of interleukin 10, and an abridged recruitment of inflammatory monocytes to the inflamed tissue. CONCLUSIONS Altogether, these findings indicate that [SRSRY] may be considered as a new drug useful for the pharmacological treatment of chronic inflammatory diseases, such as inflammatory bowel diseases.
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Affiliation(s)
- Marco Genua
- *IBD Center, Humanitas Research Institute, Rozzano, Italy; †Department of Translational Medicine, Università degli Studi di Milano, Milan, Italy; ‡Neoplastic Progression Unit, Department of Experimental Oncology, IRCCS Istituto Nazionale Tumori "Fondazione G. Pascale," Naples, Italy; §SUN, Second University of Naples, Naples, Italy; ‖Department of Pharmacy, University Federico II, Naples, Italy; and ¶Hunimed-Humanitas University, Milan, Italy
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Abstract
G protein-coupled receptors (GPCRs) are often pleiotropically linked to numerous cellular signaling mechanisms in cells, and it is now known that many agonists differentially activate some signaling pathways at the expense of others. The mechanism for this effect is the stabilization of different active receptor states by different agonists, and it leads to varying qualities of efficacy for different agonists. Agonist bias is a powerful mechanism to amplify beneficial signals and diminish harmful signals, and thus improve the overall profile of agonist ligands. This unit describes a method to quantify agonist bias with a scale that enables medicinal chemists to amplify or reduce these effects in new molecules. The method is based on the Black/Leff operational model and yields a statistical estimate of the confidence for bias measurements. © 2016 by John Wiley & Sons, Inc.
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Affiliation(s)
- Terry Kenakin
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, North Carolina
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23
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Lee HS, Seok C, Im W. Potential Application of Alchemical Free Energy Simulations to Discriminate GPCR Ligand Efficacy. J Chem Theory Comput 2016; 11:1255-66. [PMID: 26579772 DOI: 10.1021/ct5008907] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
G protein-coupled receptors (GPCRs) play fundamental roles in physiological processes by modulating diverse signaling pathways and thus have been one of the most important drug targets. Based on the fact that GPCR-mediated signaling is modulated in a ligand-specific manner such as agonist, inverse agonist, and neutral antagonist (termed ligand efficacy), quantitative characterization of the ligand efficacy is essential for rational design of selective modulators for GPCR targets. As experimental approaches for this purpose are time-, cost-, and labor-intensive, computational tools that can systematically predict GPCR ligand efficacy can have a big impact on GPCR drug design. Here, we have performed free energy perturbation molecular dynamics simulations to calculate absolute binding free energy of an inverse agonist, a neutral antagonist, and an agonist to β2-adrenergic receptor (β2-AR) active and inactive states, respectively, in explicit lipid bilayers. Relatively short alchemical free energy calculations reveal that both the time-series of the total binding free energy and decomposed energy contributions can be used as relevant physical properties to discriminate β2-AR ligand efficacy. This study illustrates a merit of the current approach over simple, fast docking calculations or highly expensive millisecond-time scale simulations.
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Affiliation(s)
- Hui Sun Lee
- Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas , 2030 Becker Drive, Lawrence, Kansas 66047, United States
| | - Chaok Seok
- Department of Chemistry, Seoul National University , Seoul 151-747, Republic of Korea
| | - Wonpil Im
- Department of Molecular Biosciences and Center for Computational Biology, The University of Kansas , 2030 Becker Drive, Lawrence, Kansas 66047, United States
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24
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Retinal Conformation Changes Rhodopsin's Dynamic Ensemble. Biophys J 2016; 109:608-17. [PMID: 26244742 DOI: 10.1016/j.bpj.2015.06.046] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 06/17/2015] [Accepted: 06/19/2015] [Indexed: 11/23/2022] Open
Abstract
G protein-coupled receptors are vital membrane proteins that allosterically transduce biomolecular signals across the cell membrane. However, the process by which ligand binding induces protein conformation changes is not well understood biophysically. Rhodopsin, the mammalian dim-light receptor, is a unique test case for understanding these processes because of its switch-like activity; the ligand, retinal, is bound throughout the activation cycle, switching from inverse agonist to agonist after absorbing a photon. By contrast, the ligand-free opsin is outside the activation cycle and may behave differently. We find that retinal influences rhodopsin dynamics using an ensemble of all-atom molecular dynamics simulations that in aggregate contain 100 μs of sampling. Active retinal destabilizes the inactive state of the receptor, whereas the active ensemble was more structurally homogenous. By contrast, simulations of an active-like receptor without retinal present were much more heterogeneous than those containing retinal. These results suggest allosteric processes are more complicated than a ligand inducing protein conformational changes or simply capturing a shifted ensemble as outlined in classic models of allostery.
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25
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Allegretti M, Cesta MC, Locati M. Allosteric Modulation of Chemoattractant Receptors. Front Immunol 2016; 7:170. [PMID: 27199992 PMCID: PMC4852175 DOI: 10.3389/fimmu.2016.00170] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 04/18/2016] [Indexed: 01/05/2023] Open
Abstract
Chemoattractants control selective leukocyte homing via interactions with a dedicated family of related G protein-coupled receptor (GPCR). Emerging evidence indicates that the signaling activity of these receptors, as for other GPCR, is influenced by allosteric modulators, which interact with the receptor in a binding site distinct from the binding site of the agonist and modulate the receptor signaling activity in response to the orthosteric ligand. Allosteric modulators have a number of potential advantages over orthosteric agonists/antagonists as therapeutic agents and offer unprecedented opportunities to identify extremely selective drug leads. Here, we resume evidence of allosterism in the context of chemoattractant receptors, discussing in particular its functional impact on functional selectivity and probe/concentration dependence of orthosteric ligands activities.
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Affiliation(s)
| | | | - Massimo Locati
- Department of Medical Biotechnologies and Translational Medicine, University of Milan, Segrate, Italy; Humanitas Clinical and Research Center, Rozzano, Italy
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26
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Affiliation(s)
- Anne Tromelin
- CNRS; UMR6265 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- INRA; UMR1324 Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
- Université de Bourgogne; UMR Centre des Sciences du Goût et de l'Alimentation; F-21000 Dijon France
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27
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Kakarala KK, Jamil K. Biased signaling: potential agonist and antagonist of PAR2. J Biomol Struct Dyn 2015; 34:1363-76. [DOI: 10.1080/07391102.2015.1079556] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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28
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Pan JX, Wang ZL, Li N, Zhang N, Wang P, Tang HH, Zhang T, Yu HP, Zhang R, Zheng T, Fang Q, Wang R. Effects of neuropeptide FF and related peptides on the antinociceptive activities of VD-hemopressin(α) in naive and cannabinoid-tolerant mice. Eur J Pharmacol 2015; 767:119-25. [PMID: 26472125 DOI: 10.1016/j.ejphar.2015.10.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2015] [Revised: 09/20/2015] [Accepted: 10/08/2015] [Indexed: 01/15/2023]
Abstract
Neuropeptide FF (NPFF) system has recently been reported to modulate cannabinoid-induced antinociception. The aim of the present study was to further investigate the roles of NPFF system in the antinociceptive effects induced by intracerebroventricular (i.c.v.) administration of mouse VD-hemopressin(α), a novel endogenous agonist of cannabinoid CB1 receptor, in naive and VD-hemopressin(α)-tolerant mice. The effects of NPFF system on the antinociception induced by VD-hemopressin(α) were investigated in the radiant heat tail-flick test in naive mice and VD-hemopressin(α)-tolerant mice. The cannabinoid-tolerant mice were produced by given daily injections of VD-hemopressin(α) (20 nmol, i.c.v.) for 5 days and the antinociception was measured on day 6. In naive mice, intracerebroventricular injection of NPFF dose-dependently attenuated central analgesia of VD-hemopressin(α). In contrast, neuropeptide VF (NPVF) and D.NP(N-Me)AFLFQPQRF-NH2 (dNPA), two highly selective agonists for Neuropeptide FF1 and Neuropeptide FF2 receptors, enhanced VD-hemopressin(α)-induced antinociception in a dose-dependent manner. In addition, the VD-hemopressin(α)-modulating activities of NPFF and related peptides were antagonized by the Neuropeptide FF receptors selective antagonist 1-adamantanecarbonyl-RF-NH2 (RF9). In VD-hemopressin(α)-tolerant mice, NPFF failed to modify VD-hemopressin(α)-induced antinociception. However, both neuropeptide VF and dNPA dose-dependently potentiated the antinociception of VD-hemopressin(α) and these cannabinoid-potentiating effects were reduced by RF9. The present works support the cannabinoid-modulating character of NPFF system in naive and cannabinoid-tolerant mice. In addition, the data suggest that a chronic cannabinoid treatment modifies the pharmacological profiles of NPFF, but not the cannabinoid-potentiating effects of neuropeptide VF and dNPA.
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Affiliation(s)
- Jia-Xin Pan
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Zi-Long Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Ning Li
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Nan Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Pei Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Hong-Hai Tang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Ting Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Hong-Ping Yu
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Run Zhang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Ting Zheng
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China
| | - Quan Fang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China.
| | - Rui Wang
- Key Laboratory of Preclinical Study for New Drugs of Gansu Province, and Institute of Physiology, School of Basic Medical Sciences, Lanzhou University, 199 Donggang West Road, Lanzhou, 730000, PR China.
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29
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Sirohi S, Walker BM. Maturational alterations in constitutive activity of medial prefrontal cortex kappa-opioid receptors in Wistar rats. J Neurochem 2015; 135:659-65. [PMID: 26257334 DOI: 10.1111/jnc.13279] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Revised: 08/03/2015] [Accepted: 08/04/2015] [Indexed: 02/02/2023]
Abstract
Opioid receptors can display spontaneous agonist-independent G-protein signaling (basal signaling/constitutive activity). While constitutive κ-opioid receptor (KOR) activity has been documented in vitro, it remains unknown if KORs are constitutively active in native systems. Using [(35) S] guanosine 5'-O-[gamma-thio] triphosphate coupling assay that measures receptor functional state, we identified the presence of medial prefrontal cortex KOR constitutive activity in young rats that declined with age. Furthermore, basal signaling showed an age-related decline and was insensitive to neutral opioid antagonist challenge. Collectively, the present data are first to demonstrate age-dependent alterations in the medial prefrontal cortex KOR constitutive activity in rats and changes in the constitutive activity of KORs can differentially impact KOR ligand efficacy. These data provide novel insights into the functional properties of the KOR system and warrant further consideration of KOR constitutive activity in normal and pathophysiological behavior. Opioid receptors exhibit agonist-independent constitutive activity; however, kappa-opioid receptor (KOR) constitutive activity has not been demonstrated in native systems. Our results confirm KOR constitutive activity in the medial prefrontal cortex (mPFC) that declines with age. With the ability to presynaptically inhibit multiple neurotransmitter systems in the mPFC, maturational or patho-logical alterations in constitutive activity could disrupt corticofugal glutamatergic pyramidal projection neurons mediating executive function. Regulation of KOR constitutive activity could serve as a therapeutic target to treat compromised executive function.
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Affiliation(s)
- Sunil Sirohi
- Laboratory of Alcoholism and Addictions Neuroscience, Department of Psychology, Washington State University, Pullman, Washington, USA.,Department of Integrative Physiology & Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA
| | - Brendan M Walker
- Laboratory of Alcoholism and Addictions Neuroscience, Department of Psychology, Washington State University, Pullman, Washington, USA.,Department of Integrative Physiology & Neuroscience, College of Veterinary Medicine, Washington State University, Pullman, Washington, USA.,Graduate Program in Neuroscience, Washington State University, Pullman, Washington, USA.,Translational Addiction Research Center, Washington State University, Pullman, Washington, USA
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30
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Gandhimathi A, Sowdhamini R. Molecular modelling of human 5-hydroxytryptamine receptor (5-HT2A) and virtual screening studies towards the identification of agonist and antagonist molecules. J Biomol Struct Dyn 2015; 34:952-70. [DOI: 10.1080/07391102.2015.1062802] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- A. Gandhimathi
- National Centre for Biological Sciences (TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India
| | - R. Sowdhamini
- National Centre for Biological Sciences (TIFR), GKVK Campus, Bellary Road, Bangalore 560065, India
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31
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Staljanssens D, Rico CA, Park M, Van Camp J, Yu N, Huber T, Sakmar TP, Smagghe G. Development of a CCK1R-membrane nanoparticle as a fish-out tool for bioactive peptides. Peptides 2015; 68:219-27. [PMID: 25451329 DOI: 10.1016/j.peptides.2014.10.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2014] [Revised: 10/17/2014] [Accepted: 10/20/2014] [Indexed: 11/22/2022]
Abstract
The cholecystokinin receptor type 1 (CCK1R) is a G protein-coupled receptor (GPCR) that is involved in several biological processes including the regulation of the secretion of digestive enzymes. The peptide hormone cholecystokinin (CCK) binds to CCK1R, which is an important pharmacological target for several diseases, including obesity. Interestingly, nutritional dietary peptides also appear to activate CCK1R, and may play a role in CCK1R signaling in the gut. In this study, a novel technique to screen for CCK1R ligands based on affinity-selection is described. Functional expressed CCK1R is reconstituted into membrane nanoparticles called NABBs (nanoscale apo-lipoprotein bound bilayers). NABBs are native-like bilayer membrane systems for incorporation of GPCRs. CCK1R-NABBs were characterized using a fluorescently labeled CCK analog and can be used as a cutting-edge technology to screen for CCK1R ligands using affinity-selection mass spectrometry.
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Affiliation(s)
- Dorien Staljanssens
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium; Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Carlos A Rico
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY 10065, USA
| | - Minyoung Park
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY 10065, USA
| | - John Van Camp
- Department of Food Safety and Food Quality, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Na Yu
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Thomas Huber
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY 10065, USA
| | - Thomas P Sakmar
- Laboratory of Chemical Biology & Signal Transduction, The Rockefeller University, New York, NY 10065, USA; Center for Alzheimer Research, Division for Neurogeriatrics, Department of Neurobiology, Care Sciences and Society, Karolinska Institute, SE-141 57 Huddinge, Sweden
| | - Guy Smagghe
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.
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LeVine MV, Weinstein H. AIM for Allostery: Using the Ising Model to Understand Information Processing and Transmission in Allosteric Biomolecular Systems. ENTROPY 2015; 17:2895-2918. [PMID: 26594108 PMCID: PMC4652859 DOI: 10.3390/e17052895] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
In performing their biological functions, molecular machines must process and transmit information with high fidelity. Information transmission requires dynamic coupling between the conformations of discrete structural components within the protein positioned far from one another on the molecular scale. This type of biomolecular “action at a distance” is termed allostery. Although allostery is ubiquitous in biological regulation and signal transduction, its treatment in theoretical models has mostly eschewed quantitative descriptions involving the system's underlying structural components and their interactions. Here, we show how Ising models can be used to formulate an approach to allostery in a structural context of interactions between the constitutive components by building simple allosteric constructs we termed Allosteric Ising Models (AIMs). We introduce the use of AIMs in analytical and numerical calculations that relate thermodynamic descriptions of allostery to the structural context, and then show that many fundamental properties of allostery, such as the multiplicative property of parallel allosteric channels, are revealed from the analysis of such models. The power of exploring mechanistic structural models of allosteric function in more complex systems by using AIMs is demonstrated by building a model of allosteric signaling for an experimentally well-characterized asymmetric homodimer of the dopamine D2 receptor.
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Affiliation(s)
- Michael V. LeVine
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
- HRH Prince Alwaleed Bin Talal Bin Abdulaziz Alsaud Institute of Computational Biomedicine, Weill Cornell Medical College, Cornell University, New York, NY 10065, USA
- Author to whom correspondence should be addressed;
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Stahl EL, Zhou L, Ehlert FJ, Bohn LM. A novel method for analyzing extremely biased agonism at G protein-coupled receptors. Mol Pharmacol 2015; 87:866-77. [PMID: 25680753 DOI: 10.1124/mol.114.096503] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 02/13/2015] [Indexed: 01/14/2023] Open
Abstract
Seven transmembrane receptors were originally named and characterized based on their ability to couple to heterotrimeric G proteins. The assortment of coupling partners for G protein-coupled receptors has subsequently expanded to include other effectors (most notably the βarrestins). This diversity of partners available to the receptor has prompted the pursuit of ligands that selectively activate only a subset of the available partners. A biased or functionally selective ligand may be able to distinguish between different active states of the receptor, and this would result in the preferential activation of one signaling cascade more than another. Although application of the "standard" operational model for analyzing ligand bias is useful and suitable in most cases, there are limitations that arise when the biased agonist fails to induce a significant response in one of the assays being compared. In this article, we describe a quantitative method for measuring ligand bias that is particularly useful for such cases of extreme bias. Using simulations and experimental evidence from several κ opioid receptor agonists, we illustrate a "competitive" model for quantitating the degree and direction of bias. By comparing the results obtained from the competitive model with the standard model, we demonstrate that the competitive model expands the potential for evaluating the bias of very partial agonists. We conclude the competitive model provides a useful mechanism for analyzing the bias of partial agonists that exhibit extreme bias.
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Affiliation(s)
- Edward L Stahl
- Departments of Molecular Therapeutics and Neuroscience, The Scripps Research Institute, Jupiter, Florida (E.L.S., L.Z., L.M.B.); and Department of Pharmacology, School of Medicine, University of California-Irvine, Irvine, California (F.J.E.)
| | - Lei Zhou
- Departments of Molecular Therapeutics and Neuroscience, The Scripps Research Institute, Jupiter, Florida (E.L.S., L.Z., L.M.B.); and Department of Pharmacology, School of Medicine, University of California-Irvine, Irvine, California (F.J.E.)
| | - Frederick J Ehlert
- Departments of Molecular Therapeutics and Neuroscience, The Scripps Research Institute, Jupiter, Florida (E.L.S., L.Z., L.M.B.); and Department of Pharmacology, School of Medicine, University of California-Irvine, Irvine, California (F.J.E.)
| | - Laura M Bohn
- Departments of Molecular Therapeutics and Neuroscience, The Scripps Research Institute, Jupiter, Florida (E.L.S., L.Z., L.M.B.); and Department of Pharmacology, School of Medicine, University of California-Irvine, Irvine, California (F.J.E.)
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Tao YX. Constitutive activity in melanocortin-4 receptor: biased signaling of inverse agonists. ADVANCES IN PHARMACOLOGY 2015; 70:135-54. [PMID: 24931195 DOI: 10.1016/b978-0-12-417197-8.00005-5] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The melanocortin-4 receptor (MC4R) is a critical regulator of energy homeostasis, including both energy intake and energy expenditure. It mediates the actions of a number of hormones on energy balance. The endogenous ligands for MC4R include peptide agonists derived from processing of proopiomelanocortin and the antagonist Agouti-related peptide (AgRP). Wild-type MC4R has some basal (constitutive) activity. Naturally occurring and laboratory-generated mutations have been identified, which results in either increased or decreased basal activities. Impaired basal signaling has been suggested to be a cause of dysregulated energy homeostasis and early-onset obesity, although several constitutively active mutations have also been identified from obese patients. AgRP and several small-molecule antagonists have been shown to be inverse agonists in the Gs-cAMP pathway. However, in the extracellular signal-regulated kinase (ERK) 1/2 pathway, we showed that these inverse agonists are potent agonists, demonstrating convincingly that they are biased ligands. We also showed that some mutations that do not cause constitutive activation in the Gs-cAMP pathway cause constitutive activation in the ERK1/2 pathway, suggesting that they are biased receptors. The physiological and potential pathophysiological relevance of the biased constitutive signaling in MC4R and therapeutic potential remain to be investigated.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University, Auburn, Alabama, USA.
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35
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Abstract
This chapter describes a method to quantify biased signaling effects of agonists; this approach can furnish a scale for medicinal chemists to optimize biased profiles. Biased ligands have different pharmacological properties on a molecular level (stabilization of different receptor active states) and thus can have different pharmacological profiles therapeutically. The calculation of transduction ratios (ΔΔlog(τ/K A)) values (where τ is efficacy and K A a measure of affinity) allows the identification of agonists that demonstrate unique signaling either for different signaling pathways linked to the receptor, differences in cellular host, effects of receptor mutation, or receptor selectivity profiles. The procedure includes statistical methods to assess the significance of these effects.
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Affiliation(s)
- Terry Kenakin
- Department of Pharmacology, University of North Carolina School of Medicine, Room 4042 Genetic Medicine Building, CB# 7365, 120 Mason Farm Road, Chapel Hill, NC, 27599-7365, USA,
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Characterization of a prawn OA/TA receptor in Xenopus oocytes suggests functional selectivity between octopamine and tyramine. PLoS One 2014; 9:e111314. [PMID: 25350749 PMCID: PMC4211885 DOI: 10.1371/journal.pone.0111314] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/30/2014] [Indexed: 11/19/2022] Open
Abstract
Here we report the characterization of an octopamine/tyramine (OA/TA or TyrR1) receptor (OA/TAMac) cloned from the freshwater prawn, Macrobrachium rosenbergii, an animal used in the study of agonistic social behavior. The invertebrate OA/TA receptors are seven trans-membrane domain G-protein coupled receptors that are related to vertebrate adrenergic receptors. Behavioral studies in arthropods indicate that octopaminergic signaling systems modulate fight or flight behaviors with octopamine and/or tyramine functioning in a similar way to the adrenalins in vertebrate systems. Despite the importance of octopamine signaling in behavioral studies of decapod crustaceans there are no functional data available for any of their octopamine or tyramine receptors. We expressed OA/TAMac in Xenopus oocytes where agonist-evoked trans-membrane currents were used as readouts of receptor activity. The currents were most effectively evoked by tyramine but were also evoked by octopamine and dopamine. They were effectively blocked by yohimbine. The electrophysiological approach we used enabled the continuous observation of complex dynamics over time. Using voltage steps, we were able to simultaneously resolve two types of endogenous currents that are affected over different time scales. At higher concentrations we observe that octopamine and tyramine can produce different and opposing effects on both of these currents, presumably through the activity of the single expressed receptor type. The pharmacological profile and apparent functional-selectivity are consistent with properties first observed in the OA/TA receptor from the insect Drosophila melanogaster. As the first functional data reported for any crustacean OA/TA receptor, these results suggest that functional-selectivity between tyramine and octopamine is a feature of this receptor type that may be conserved among arthropods.
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Leonis G, Avramopoulos A, Salmas RE, Durdagi S, Yurtsever M, Papadopoulos MG. Elucidation of Conformational States, Dynamics, and Mechanism of Binding in Human κ-Opioid Receptor Complexes. J Chem Inf Model 2014; 54:2294-308. [DOI: 10.1021/ci5002873] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Georgios Leonis
- Institute
of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens, Attiki 11635, Greece
| | - Aggelos Avramopoulos
- Institute
of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens, Attiki 11635, Greece
| | - Ramin Ekhteiari Salmas
- Department
of Chemistry, Istanbul Technical University, Istanbul, Istanbul 34469, Turkey
| | - Serdar Durdagi
- Department
of Biophysics, School of Medicine, Bahcesehir University, Istanbul, Istanbul 34349, Turkey
| | - Mine Yurtsever
- Department
of Chemistry, Istanbul Technical University, Istanbul, Istanbul 34469, Turkey
| | - Manthos G. Papadopoulos
- Institute
of Biology, Medicinal Chemistry and Biotechnology, National Hellenic Research Foundation, 48 Vas. Constantinou Avenue, Athens, Attiki 11635, Greece
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Singh N, Yadav M, Singh AK, Kumar H, Dwivedi SKD, Mishra JS, Gurjar A, Manhas A, Chandra S, Yadav PN, Jagavelu K, Siddiqi MI, Trivedi AK, Chattopadhyay N, Sanyal S. Synthetic FXR agonist GW4064 is a modulator of multiple G protein-coupled receptors. Mol Endocrinol 2014; 28:659-73. [PMID: 24597548 DOI: 10.1210/me.2013-1353] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The synthetic nuclear bile acid receptor (farnesoid X receptor [FXR]) agonist GW4064 is extensively used as a specific pharmacological tool to illustrate FXR functions. We noticed that GW4064 activated empty luciferase reporters in FXR-deficient HEK-293T cells. We postulated that this activity of GW4064 might be routed through as yet unknown cellular targets and undertook an unbiased exploratory approach to identify these targets. Investigations revealed that GW4064 activated cAMP and nuclear factor for activated T-cell response elements (CRE and NFAT-RE, respectively) present on these empty reporters. Whereas GW4064-induced NFAT-RE activation involved rapid intracellular Ca(2+) accumulation and NFAT nuclear translocation, CRE activation involved soluble adenylyl cyclase-dependent cAMP accumulation and Ca(2+)-calcineurin-dependent nuclear translocation of transducers of regulated CRE-binding protein 2. Use of dominant negative heterotrimeric G-protein minigenes revealed that GW4064 caused activation of Gαi/o and Gq/11 G proteins. Sequential pharmacological inhibitor-based screening and radioligand-binding studies revealed that GW4064 interacted with multiple G protein-coupled receptors. Functional studies demonstrated that GW4064 robustly activated H1 and H4 and inhibited H2 histamine receptor signaling events. We also found that MCF-7 breast cancer cells, reported to undergo GW4064-induced apoptosis in an FXR-dependent manner, did not express FXR, and the GW4064-mediated apoptosis, also apparent in HEK-293T cells, could be blocked by selective histamine receptor regulators. Taken together, our results demonstrate identification of histamine receptors as alternate targets for GW4064, which not only necessitates cautious interpretation of the biological functions attributed to FXR using GW4064 as a pharmacological tool but also provides a basis for the rational designing of new pharmacophores for histamine receptor modulation.
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Affiliation(s)
- Nidhi Singh
- Division of Biochemistry (N.S., M.Y., A.K.S., H.K., J.S.M., A.G., S.S.), Division of Endocrinology and Center for Anabolic Skeletal Targets in Health and Illness (S.K.D.D., N.C.), Division of Pharmacology (A.M., P.N.Y., K.J.), and Division of Molecular and Structural Biology (S.C., M.I.S.), Council of Scientific and Industrial Research-Central Drug Research Institute, Lucknow 226031, Uttar Pradesh, India
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Ahmad R, Goffin K, Van den Stock J, De Winter FL, Cleeren E, Bormans G, Tournoy J, Persoons P, Van Laere K, Vandenbulcke M. In vivo type 1 cannabinoid receptor availability in Alzheimer's disease. Eur Neuropsychopharmacol 2014; 24:242-50. [PMID: 24189376 DOI: 10.1016/j.euroneuro.2013.10.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Revised: 10/04/2013] [Accepted: 10/09/2013] [Indexed: 11/16/2022]
Abstract
The endocannabinoid system (ECS) is an important modulatory and potentially neuroprotective homeostatic system in the brain. In Alzheimer's disease (AD), the role of type 1 cannabinoid receptor (CB₁R) is unclear, with contradictory findings in post-mortem studies showing upregulation, downregulation or unchanged CB₁R status. We have investigated CB₁R availability in vivo in patients with AD, in relation to amyloid deposition, cognitive functioning and apolipoprotein E (ApoE) genotype. Eleven AD patients and 7 healthy volunteers (HV) underwent combined [¹⁸F]MK-9470 PET and [¹¹C]PIB PET scans to assess CB₁R availability and amyloid deposition, respectively, and T1 volumetric MRI for partial volume correction. We found no difference in CB₁R availability between AD and HV, VOI-based fractional uptake values (FUR) were 0.043±0.01 for AD and 0.045±0.01 for controls (p=0.9). CB₁R availability did not correlate with neuropsychological test scores and was not modulated by ApoE genotype. As expected, global [¹¹C]PIB SUVR (standardized uptake value ratio) was increased in AD (SUVR 1.9±0.3) compared to HV (1.2±0.1) with p<0.001, but no correlation was found between amyloid β (Aβ) deposition and CB₁R availability. In conclusion, we found no in vivo evidence for a difference in CB₁R availability in AD compared to age-matched controls. Taken together with recently reported in vivo CB₁R changes in Parkinson's and Huntington's disease, these data suggest that the CB₁R is differentially involved in neurodegenerative disorders.
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Affiliation(s)
- Rawaha Ahmad
- Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Belgium; Department of Imaging & Pathology, KU Leuven, Belgium.
| | - Karolien Goffin
- Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Belgium; Department of Imaging & Pathology, KU Leuven, Belgium
| | - Jan Van den Stock
- Department of Old Age Psychiatry, University Hospitals Leuven, Belgium; Department of Neurosciences, KU Leuven, Belgium
| | - François-Laurent De Winter
- Department of Old Age Psychiatry, University Hospitals Leuven, Belgium; Department of Neurosciences, KU Leuven, Belgium
| | - Evy Cleeren
- Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Belgium; Department of Imaging & Pathology, KU Leuven, Belgium
| | - Guy Bormans
- Laboratory for Radiopharmacy, KU Leuven, Belgium
| | - Jos Tournoy
- Geriatric Medicine, University Hospitals Leuven, Belgium; Department of Clinical and Experimental Medicine, KU Leuven, Belgium
| | - Philippe Persoons
- Department of Old Age Psychiatry, University Hospitals Leuven, Belgium; Department of Neurosciences, KU Leuven, Belgium
| | - Koen Van Laere
- Nuclear Medicine and Molecular Imaging, University Hospitals Leuven, Belgium; Department of Imaging & Pathology, KU Leuven, Belgium
| | - Mathieu Vandenbulcke
- Department of Old Age Psychiatry, University Hospitals Leuven, Belgium; Department of Neurosciences, KU Leuven, Belgium
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Abstract
It is now established that agonists do not uniformly activate pleiotropic signaling mechanisms initiated by receptors but rather can bias signals according to the unique receptor conformations they stabilize. One of the important emerging signaling systems where this can occur is through β-arrestin. This chapter discusses biased signaling where emphasis or de-emphasis of β-arrestin signaling is postulated (or been shown) to be beneficial. The chapter specifically focuses on methods to quantify biased effects; these methods furnish scales that can be used in the process of optimizing biased agonism (and antagonism) for therapeutic benefit. Specifically, methods to derive ΔΔLog(τ/K A) or ΔΔLog(Relative Activity) values are described to do this.
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Affiliation(s)
- Terry Kenakin
- Department of Pharmacology, University of North Carolina School of Medicine, 120 Mason Farm Road, Room 4042, Genetic Medicine Building, CB# 7365, Chapel Hill, NC, 27599-7365, USA,
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41
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Roche D, Gil D, Giraldo J. Mathematical modeling of G protein-coupled receptor function: what can we learn from empirical and mechanistic models? ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 796:159-81. [PMID: 24158805 DOI: 10.1007/978-94-007-7423-0_8] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Empirical and mechanistic models differ in their approaches to the analysis of pharmacological effect. Whereas the parameters of the former are not physical constants those of the latter embody the nature, often complex, of biology. Empirical models are exclusively used for curve fitting, merely to characterize the shape of the E/[A] curves. Mechanistic models, on the contrary, enable the examination of mechanistic hypotheses by parameter simulation. Regretfully, the many parameters that mechanistic models may include can represent a great difficulty for curve fitting, representing, thus, a challenge for computational method development. In the present study some empirical and mechanistic models are shown and the connections, which may appear in a number of cases between them, are analyzed from the curves they yield. It may be concluded that systematic and careful curve shape analysis can be extremely useful for the understanding of receptor function, ligand classification and drug discovery, thus providing a common language for the communication between pharmacologists and medicinal chemists.
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Affiliation(s)
- David Roche
- Laboratory of Systems Pharmacology and Bioinformatics, Institut de Neurociències and Unitat de Bioestadística, Universitat Autònoma de Barcelona, 08193, Bellaterra, Spain
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Park PSH. Constitutively active rhodopsin and retinal disease. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2014; 70:1-36. [PMID: 24931191 DOI: 10.1016/b978-0-12-417197-8.00001-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Rhodopsin is the light receptor in rod photoreceptor cells of the retina that initiates scotopic vision. In the dark, rhodopsin is bound to the chromophore 11-cis retinal, which locks the receptor in an inactive state. The maintenance of an inactive rhodopsin in the dark is critical for rod photoreceptor cells to remain highly sensitive. Perturbations by mutation or the absence of 11-cis retinal can cause rhodopsin to become constitutively active, which leads to the desensitization of photoreceptor cells and, in some instances, retinal degeneration. Constitutive activity can arise in rhodopsin by various mechanisms and can cause a variety of inherited retinal diseases including Leber congenital amaurosis, congenital night blindness, and retinitis pigmentosa. In this review, the molecular and structural properties of different constitutively active forms of rhodopsin are overviewed, and the possibility that constitutive activity can arise from different active-state conformations is discussed.
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Affiliation(s)
- Paul Shin-Hyun Park
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, USA.
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43
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Ayoub MA, Pin JP. Interaction of Protease-Activated Receptor 2 with G Proteins and β-Arrestin 1 Studied by Bioluminescence Resonance Energy Transfer. Front Endocrinol (Lausanne) 2013; 4:196. [PMID: 24391627 PMCID: PMC3869048 DOI: 10.3389/fendo.2013.00196] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/21/2013] [Accepted: 12/08/2013] [Indexed: 11/13/2022] Open
Abstract
G protein-coupled receptors are well recognized as being able to activate several signaling pathways through the activation of different G proteins as well as other signaling proteins such as β-arrestins. Therefore, understanding how such multiple GPCR-mediated signaling can be integrated constitute an important aspect. Here, we applied bioluminescence resonance energy transfer (BRET) to shed more light on the G protein coupling profile of trypsin receptor, or protease-activated receptor 2 (PAR2), and its interaction with β-arrestin1. Using YFP and Rluc fusion constructs expressed in COS-7 cells, BRET data revealed a pre-assembly of PAR2 with both Gαi1 and Gαo and a rapid and transient activation of these G proteins upon receptor activation. In contrast, no pre-assembly of PAR2 with Gα12 could be detected and their physical association can be measured with a very slow and sustained kinetics similar to that of β-arrestin1 recruitment. These data demonstrate the coupling of PAR2 with Gαi1, Gαo, and Gα12 in COS-7 cells with differences in the kinetics of GPCR-G protein coupling, a parameter that very likely influences the cellular response. Moreover, this further illustrates that pre-assembly or agonist-induced G protein interaction depends on receptor-G protein pairs indicating another level of complexity and regulation of the signaling of GPCR-G protein complexes and its multiplicity.
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Affiliation(s)
- Mohammed Akli Ayoub
- Département de Pharmacologie Moléculaire, Institut de Génomique Fonctionnelle, Montpellier, France
- UMR5203, Centre national de la recherche scientifique, Universités Montpellier 1 & 2, Montpellier, France
- U661, Institut national de la santé et de la recherche médicale, Universités Montpellier 1 & 2, Montpellier, France
| | - Jean-Philippe Pin
- Département de Pharmacologie Moléculaire, Institut de Génomique Fonctionnelle, Montpellier, France
- UMR5203, Centre national de la recherche scientifique, Universités Montpellier 1 & 2, Montpellier, France
- U661, Institut national de la santé et de la recherche médicale, Universités Montpellier 1 & 2, Montpellier, France
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Clarke WP, Chavera TA, Silva M, Sullivan LC, Berg KA. Signalling profile differences: paliperidone versus risperidone. Br J Pharmacol 2013; 170:532-45. [PMID: 23826915 PMCID: PMC3791992 DOI: 10.1111/bph.12295] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2013] [Revised: 06/20/2013] [Accepted: 06/25/2013] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND AND PURPOSE Paliperidone is an active metabolite of the second-generation atypical antipsychotic, risperidone recently approved for the treatment of schizophrenia and schizoaffective disorder. Because paliperidone differs from risperidone by only a single hydroxyl group, questions have been raised as to whether there are significant differences in the effects elicited between these two drugs. EXPERIMENTAL APPROACH We compared the relative efficacies of paliperidone versus risperidone to regulate several cellular signalling pathways coupled to four selected GPCR targets that are important for either therapeutic or adverse effects: human dopamine D2 , human serotonin 2A receptor subtype (5-HT2A ), human serotonin 2C receptor subtype and human histamine H1 receptors. KEY RESULTS Whereas the relative efficacies of paliperidone and risperidone were the same for some responses, significant differences were found for several receptor-signalling systems, with paliperidone having greater or less relative efficacy than risperidone depending upon the receptor-response pair. Interestingly, for 5-HT2A -mediated recruitment of β-arrestin, 5-HT2A -mediated sensitization of ERK, and dopamine D2 -mediated sensitization of adenylyl cyclase signalling, both paliperidone and risperidone behaved as agonists. CONCLUSIONS AND IMPLICATIONS These results suggest that the single hydroxyl group of paliperidone promotes receptor conformations that can differ from those of risperidone leading to differences in the spectrum of regulation of cellular signal transduction cascades. Such differences in signalling at the cellular level could lead to differences between paliperidone and risperidone in therapeutic efficacy or in the generation of adverse effects.
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MESH Headings
- Adenylyl Cyclases/metabolism
- Animals
- Antipsychotic Agents/chemistry
- Antipsychotic Agents/pharmacology
- Arrestins/metabolism
- CHO Cells
- Cricetinae
- Cricetulus
- Dopamine Agonists/pharmacology
- Dose-Response Relationship, Drug
- Drug Inverse Agonism
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Histamine Agonists/pharmacology
- Humans
- Isoxazoles/chemistry
- Isoxazoles/pharmacology
- Molecular Structure
- Paliperidone Palmitate
- Pyrimidines/chemistry
- Pyrimidines/pharmacology
- Receptor, Serotonin, 5-HT2A/drug effects
- Receptor, Serotonin, 5-HT2A/genetics
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptor, Serotonin, 5-HT2C/drug effects
- Receptor, Serotonin, 5-HT2C/genetics
- Receptor, Serotonin, 5-HT2C/metabolism
- Receptors, Dopamine D2/drug effects
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, Histamine H1/drug effects
- Receptors, Histamine H1/genetics
- Receptors, Histamine H1/metabolism
- Risperidone/chemistry
- Risperidone/pharmacology
- Serotonin Receptor Agonists/pharmacology
- Signal Transduction/drug effects
- Structure-Activity Relationship
- Transfection
- beta-Arrestins
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Affiliation(s)
- W P Clarke
- Department of Pharmacology, University of Texas Health Science Center, San Antonio, TX, USA
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Kleinau G, Neumann S, Grüters A, Krude H, Biebermann H. Novel insights on thyroid-stimulating hormone receptor signal transduction. Endocr Rev 2013; 34:691-724. [PMID: 23645907 PMCID: PMC3785642 DOI: 10.1210/er.2012-1072] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The TSH receptor (TSHR) is a member of the glycoprotein hormone receptors, a subfamily of family A G protein-coupled receptors. The TSHR is of great importance for the growth and function of the thyroid gland. The TSHR and its endogenous ligand TSH are pivotal proteins with respect to a variety of physiological functions and malfunctions. The molecular events of TSHR regulation can be summarized as a process of signal transduction, including signal reception, conversion, and amplification. The steps during signal transduction from the extra- to the intracellular sites of the cell are not yet comprehensively understood. However, essential new insights have been achieved in recent years on the interrelated mechanisms at the extracellular region, the transmembrane domain, and intracellular components. This review contains a critical summary of available knowledge of the molecular mechanisms of signal transduction at the TSHR, for example, the key amino acids involved in hormone binding or in the structural conformational changes that lead to G protein activation or signaling regulation. Aspects of TSHR oligomerization, signaling promiscuity, signaling selectivity, phenotypes of genetic variations, and potential extrathyroidal receptor activity are also considered, because these are relevant to an understanding of the overall function of the TSHR, including physiological, pathophysiological, and pharmacological perspectives. Directions for future research are discussed.
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Affiliation(s)
- Gunnar Kleinau
- Institute of Experimental Pediatric Endocrinology, Charité-Universitätsmedizin Berlin, Ostring 3, Augustenburger Platz 1, 13353 Berlin, Germany.
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Seifert R. Functional selectivity of G-protein-coupled receptors: from recombinant systems to native human cells. Biochem Pharmacol 2013; 86:853-61. [PMID: 23933388 DOI: 10.1016/j.bcp.2013.07.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Revised: 07/25/2013] [Accepted: 07/25/2013] [Indexed: 10/26/2022]
Abstract
In the mid 1990s, it was assumed that a two-state model, postulating an inactive (R) state and an active (R*) state provides the molecular basis for GPCR activation. However, it became clear that this model could not accommodate many experimental observations. Accordingly, the two-state model was superseded by a multi-state model according to which any given ligand stabilizes a unique receptor conformation with distinct capabilities of activating down-stream G-proteins and β-arrestin. Much of this research was conducted with the β2-adrenoceptor in recombinant systems. At the molecular level, there is now no doubt anymore that ligand-specific receptor conformations, also referred to as functional selectivity, exist. This concept holds great potential for drug discovery in terms of developing drugs with higher selectivity for specific cells and/or cell functions and fewer side effects. A major challenge is the analysis for functional selectivity in native cells. Here, I discuss our current knowledge on functional selectivity of three representative GPCRs, the β2-adrenoceptor and the histamine H2- and H4-receptors, in recombinant systems and native human cells. Studies with human neutrophils and eosinophils support the concept of functional selectivity. A major strategy for the analysis of functional selectivity in native cells is to generate complete concentration/response curves with a large set of structurally diverse ligands for multiple parameters. Next, correlations of potencies and efficacies are analyzed, and deviations of the correlations from linearity are indicative for functional selectivity. Additionally, pharmacological inhibitors are used to dissect cell functions from each other.
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Affiliation(s)
- Roland Seifert
- Institute of Pharmacology, Medical School of Hannover, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
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47
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Affiliation(s)
- Alexander Thiele
- Institute of Neuroscience, Henry Wellcome Building, Newcastle University, Newcastle upon Tyne, NE2 4HH, United Kingdom;
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48
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Labrecque P, Roy SJ, Fréchette L, Iorio-Morin C, Gallant MA, Parent JL. Inverse agonist and pharmacochaperone properties of MK-0524 on the prostanoid DP1 receptor. PLoS One 2013; 8:e65767. [PMID: 23762421 PMCID: PMC3677937 DOI: 10.1371/journal.pone.0065767] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 05/01/2013] [Indexed: 01/09/2023] Open
Abstract
Prostaglandin D₂ (PGD₂) acts through two G protein-coupled receptors (GPCRs), the prostanoid DP receptor and CRTH2 also known as DP1 and DP2, respectively. Several previously characterized GPCR antagonists are now classified as inverse agonists and a number of GPCR ligands are known to display pharmacochaperone activity towards a given receptor. Here, we demonstrate that a DP1 specific antagonist, MK-0524 (also known as laropiprant), decreased basal levels of intracellular cAMP produced by DP1, a Gα(s)-coupled receptor, in HEK293 cells. This reduction in cAMP levels was not altered by pertussis toxin treatment, indicating that MK-0524 did not induce coupling of DP1 to Gα(i/o) proteins and that this ligand is a DP1 inverse agonist. Basal ERK1/2 activation by DP1 was not modulated by MK-0524. Interestingly, treatment of HEK293 cells expressing Flag-tagged DP1 with MK-0524 promoted DP1 cell surface expression time-dependently to reach a maximum increase of 50% compared to control after 24 h. In contrast, PGD₂ induced the internalization of 75% of cell surface DP1 after the same time of stimulation. The increase in DP1 cell surface targeting by MK-0524 was inhibited by Brefeldin A, an inhibitor of transport from the endoplasmic reticulum-Golgi to the plasma membrane. Confocal microscopy confirmed that a large population of DP1 remained trapped intracellularly and co-localized with calnexin, an endoplasmic reticulum marker. Redistribution of DP1 from intracellular compartments to the plasma membrane was observed following treatment with MK-0524 for 24 h. Furthermore, MK-0524 promoted the interaction between DP1 and the ANKRD13C protein, which we showed previously to display chaperone-like effects towards the receptor. We thus report that MK-0524 is an inverse agonist and a pharmacochaperone of DP1. Our findings may have important implications during therapeutic treatments with MK-0524 and for the development of new molecules targeting DP1.
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Affiliation(s)
- Pascale Labrecque
- Département de Médecine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Quebec, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Sébastien J. Roy
- Département de Médecine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Quebec, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Louis Fréchette
- Département de Médecine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Quebec, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Christian Iorio-Morin
- Département de Médecine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Quebec, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Maxime A. Gallant
- Département de Médecine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Quebec, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada
| | - Jean-Luc Parent
- Département de Médecine, Université de Sherbrooke, Sherbrooke, Quebec, Canada
- Centre de Recherche Clinique Étienne-Le Bel, Sherbrooke, Quebec, Canada
- Institut de Pharmacologie de Sherbrooke, Sherbrooke, Quebec, Canada
- * E-mail:
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49
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A3 adenosine receptor: Homology modeling and 3D-QSAR studies. J Mol Graph Model 2013; 42:60-72. [DOI: 10.1016/j.jmgm.2013.03.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Revised: 02/01/2013] [Accepted: 03/07/2013] [Indexed: 11/21/2022]
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50
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