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Buckley M, Jacob WP, Bortey L, McClain M, Ritter AL, Godfrey A, Munneke AS, Ramachandran S, Kenis S, Kolnik JC, Olofsson S, Adkins R, Kutoloski T, Rademacher L, Heinecke O, Alva A, Beets I, Francis MM, Kowalski JR. Cell non-autonomous signaling through the conserved C. elegans glycopeptide hormone receptor FSHR-1 regulates cholinergic neurotransmission. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.02.10.578699. [PMID: 38405708 PMCID: PMC10888917 DOI: 10.1101/2024.02.10.578699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2024]
Abstract
Modulation of neurotransmission is key for organismal responses to varying physiological contexts such as during infection, injury, or other stresses, as well as in learning and memory and for sensory adaptation. Roles for cell autonomous neuromodulatory mechanisms in these processes have been well described. The importance of cell non-autonomous pathways for inter-tissue signaling, such as gut-to-brain or glia-to-neuron, has emerged more recently, but the cellular mechanisms mediating such regulation remain comparatively unexplored. Glycoproteins and their G protein-coupled receptors (GPCRs) are well-established orchestrators of multi-tissue signaling events that govern diverse physiological processes through both cell-autonomous and cell non-autonomous regulation. Here, we show that follicle stimulating hormone receptor, FSHR-1, the sole Caenorhabditis elegans ortholog of mammalian glycoprotein hormone GPCRs, is important for cell non-autonomous modulation of synaptic transmission. Inhibition of fshr-1 expression reduces muscle contraction and leads to synaptic vesicle accumulation in cholinergic motor neurons. The neuromuscular and locomotor defects in fshr-1 loss-of-function mutants are associated with an underlying accumulation of synaptic vesicles, build-up of the synaptic vesicle priming factor UNC-10/RIM, and decreased synaptic vesicle release from cholinergic motor neurons. Restoration of FSHR-1 to the intestine is sufficient to restore neuromuscular activity and synaptic vesicle localization to fshr-1- deficient animals. Intestine-specific knockdown of FSHR-1 reduces neuromuscular function, indicating FSHR-1 is both necessary and sufficient in the intestine for its neuromuscular effects. Re-expression of FSHR-1 in other sites of endogenous expression, including glial cells and neurons, also restored some neuromuscular deficits, indicating potential cross-tissue regulation from these tissues as well. Genetic interaction studies provide evidence that downstream effectors gsa-1 / Gα S , acy-1 /adenylyl cyclase and sphk-1/ sphingosine kinase and glycoprotein hormone subunit orthologs, GPLA-1/GPA2 and GPLB-1/GPB5, are important for FSHR-1 modulation of the NMJ. Together, our results demonstrate that FSHR-1 modulation directs inter-tissue signaling systems, which promote synaptic vesicle release at neuromuscular synapses.
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Li H, Ma T, Hao M, Guo W, Gu J, Zhang X, Wei L. Decoding functional cell-cell communication events by multi-view graph learning on spatial transcriptomics. Brief Bioinform 2023; 24:bbad359. [PMID: 37824741 DOI: 10.1093/bib/bbad359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 08/25/2023] [Accepted: 09/18/2023] [Indexed: 10/14/2023] Open
Abstract
Cell-cell communication events (CEs) are mediated by multiple ligand-receptor (LR) pairs. Usually only a particular subset of CEs directly works for a specific downstream response in a particular microenvironment. We name them as functional communication events (FCEs) of the target responses. Decoding FCE-target gene relations is: important for understanding the mechanisms of many biological processes, but has been intractable due to the mixing of multiple factors and the lack of direct observations. We developed a method HoloNet for decoding FCEs using spatial transcriptomic data by integrating LR pairs, cell-type spatial distribution and downstream gene expression into a deep learning model. We modeled CEs as a multi-view network, developed an attention-based graph learning method to train the model for generating target gene expression with the CE networks, and decoded the FCEs for specific downstream genes by interpreting trained models. We applied HoloNet on three Visium datasets of breast cancer and liver cancer. The results detangled the multiple factors of FCEs by revealing how LR signals and cell types affect specific biological processes, and specified FCE-induced effects in each single cell. We conducted simulation experiments and showed that HoloNet is more reliable on LR prioritization in comparison with existing methods. HoloNet is a powerful tool to illustrate cell-cell communication landscapes and reveal vital FCEs that shape cellular phenotypes. HoloNet is available as a Python package at https://github.com/lhc17/HoloNet.
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Affiliation(s)
- Haochen Li
- School of Medicine, Tsinghua University, Beijing 100084, China
| | - Tianxing Ma
- MOE Key Lab of Bioinformatics, Bioinformatics Division of BNRIST and Department of Automation, Tsinghua University, Beijing 100084, China
| | - Minsheng Hao
- MOE Key Lab of Bioinformatics, Bioinformatics Division of BNRIST and Department of Automation, Tsinghua University, Beijing 100084, China
| | - Wenbo Guo
- MOE Key Lab of Bioinformatics, Bioinformatics Division of BNRIST and Department of Automation, Tsinghua University, Beijing 100084, China
| | - Jin Gu
- MOE Key Lab of Bioinformatics, Bioinformatics Division of BNRIST and Department of Automation, Tsinghua University, Beijing 100084, China
| | - Xuegong Zhang
- School of Medicine, Tsinghua University, Beijing 100084, China
- MOE Key Lab of Bioinformatics, Bioinformatics Division of BNRIST and Department of Automation, Tsinghua University, Beijing 100084, China
| | - Lei Wei
- MOE Key Lab of Bioinformatics, Bioinformatics Division of BNRIST and Department of Automation, Tsinghua University, Beijing 100084, China
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Martyniak A, Wędrychowicz A, Tomasik PJ. Endogenous Opioids in Crohn's Disease. Biomedicines 2023; 11:2037. [PMID: 37509676 PMCID: PMC10377721 DOI: 10.3390/biomedicines11072037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/16/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
Caring for patients with Crohn's disease (CD) is a serious challenge in modern medicine. The increasing incidence of CD among adolescents and the severe course of the disease create the need for new methods of diagnosis and therapy. Endogenous opioids are a group of low molecular weight chemical compounds with analgesic and anti-inflammatory properties. Endorphins, enkephalins, and dynorphins may have potentially beneficial effects on the course of CD. Previous research data on this topic are inconsistent. Some authors have reported an increase in the concentration of leukocytes during the course of inflammatory bowel disease (IBD) while others have described a downward trend, explained by DPP-IV enzyme activity. Even fewer data are available on plasma endo-opioid level. There is also a lack of comprehensive studies that have assessed the endo-opioid system in patients with IBD. Therefore, the objective of this study was to measure the serum concentrations of human β-endorphin, human proenkephalin (A), and human big dynorphin in CD patients in the acute phase of the disease, during hospital treatment, and in the remission state. All determinations were performed using ELISA kits. The results of our study showed that the concentrations of all the tested endo-opioids, especially β-endorphin and proenkephalin (A), were reduced in adolescents with CD compared to those in the healthy control group, during the acute phase of the disease, and in the remission state. Modulation of the endogenous opioid system and the use of selective nonnarcotic agonists of opioid receptors seems to be promising goals in the future treatment of CD.
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Affiliation(s)
- Adrian Martyniak
- Department of Clinical Biochemistry, Pediatric Institute, Faculty of Medicine, Jagiellonian University Medical College, 30-663 Krakow, Poland
| | - Andrzej Wędrychowicz
- Department of Pediatrics, Gastroenterology and Nutrition, Pediatric Institute, Faculty of Medicine, Jagiellonian University Medical College, 30-663 Krakow, Poland
| | - Przemysław J Tomasik
- Department of Clinical Biochemistry, Pediatric Institute, Faculty of Medicine, Jagiellonian University Medical College, 30-663 Krakow, Poland
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Pierzchała-Koziec K, Scanes CG. Avian opioid peptides: evolutionary considerations, functional roles and a challenge to address critical questions. Front Physiol 2023; 14:1164031. [PMID: 37346481 PMCID: PMC10280075 DOI: 10.3389/fphys.2023.1164031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2023] [Accepted: 05/26/2023] [Indexed: 06/23/2023] Open
Abstract
The present review considers the putative hormonal opioid peptides in birds. In birds and all other vertebrates, there are four opioid related genes encoding a series of peptides. These genes are, respectively, proenkephalin (PENK), prodynorphin (PDYN), pronociceptin (PNOC) and proopiomelanocortin (POMC). Proenkephalin (PENK) encodes Met- and Leu-enkephalin together with peptides containing met enkephalin motifs in birds, mammals and reptiles. Proopiomelanocortin (POMC) encodes β endorphin together with adrenocorticotropic hormone (ACTH), and melanocyte stimulating hormone (MSH). Prodynorphin (PDYN) encoding dynorphins A and B with α- and β-neoendorphins together intermediate polypeptides across the vertebrates. Pronociceptin (PNOC) encodes nociceptin together with possibly putative avian nocistatin and a non-opioid peptide derived from the C terminal of pronociceptin. There is a high degree of identity in the sequences of enkephalin peptides, dynorphin-A and B and nociceptin in birds and, to a less extent, across vertebrates. The opioid peptides exert effects related to pain together with other biological actions such as growth/development acting via a series of opioid receptors. What is unclear, particularly in birds, is the biological roles and interactions (additivity, antagonistic and synergistic) for the individual opioid peptides, the processing of the prohormones in different tissues and the physiological relevance of the different peptides and, particularly, of the circulating forms.
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Affiliation(s)
| | - Colin G. Scanes
- Colin G. Scanes, Department of Biological Science, University of Wisconsin Milwaukee, Milwaukee, WI, United States
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Billard E, Hébert TE, Chatenet D. EXPLORATION OF THE UROCONTRIN A SCAFFOLD YIELDS NEW UROTENSINERGIC SYSTEM ALLOSTERIC MODULATOR AND COMPETITIVE ANTAGONISTS. Biochem Pharmacol 2023; 211:115485. [PMID: 36889446 DOI: 10.1016/j.bcp.2023.115485] [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: 10/28/2022] [Revised: 02/28/2023] [Accepted: 02/28/2023] [Indexed: 03/08/2023]
Abstract
The urotensinergic system, involved in the development and/or progression of numerous pathological conditions, is composed of one G protein-coupled receptor (UT) and two endogenous ligands known as urotensin II (UII) and urotensin II-related peptide (URP). These two structurally related hormones, which exert common and divergent effects, are thought to play specific biological roles. In recent years, we have characterized an analog termed urocontrin A (UCA), i.e. [Pep4]URP, which is capable of discriminating the effects of UII from URP. Such an action could allow the delineation of the respective functions of these two endogenous ligands. In an effort to define the molecular determinants involved in this behavior and to improve the pharmacological profile of UCA, we introduced modifications from urantide, considered for some time as a lead compound for the development of UT antagonists, into UCA and assessed the binding, contractile activity and G protein signaling of these newly developed compounds. Our results show that UCA and its derivatives exert probe-dependent effects on UT antagonism, and we have further identified [Pen2, Pep4]URP as a Gq biased ligand with an insurmountable antagonism in our aortic ring contraction assay.
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Affiliation(s)
- Etienne Billard
- INRS - Centre Armand-Frappier Santé Biotechnologie, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec, Ville de Laval, Québec H7V 1B7, Canada; Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3A 1A3, Canada
| | - Terence E Hébert
- Department of Pharmacology and Therapeutics, McGill University, Montréal, Québec H3A 1A3, Canada
| | - David Chatenet
- INRS - Centre Armand-Frappier Santé Biotechnologie, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec, Ville de Laval, Québec H7V 1B7, Canada.
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Functional Characterization of Spinocerebellar Ataxia Associated Dynorphin A Mutant Peptides. Biomedicines 2021; 9:biomedicines9121882. [PMID: 34944698 PMCID: PMC8698333 DOI: 10.3390/biomedicines9121882] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 12/07/2021] [Accepted: 12/08/2021] [Indexed: 02/05/2023] Open
Abstract
Mutations in the prodynorphin gene (PDYN) are associated with the development of spinocerebellar ataxia type 23 (SCA23). Pathogenic missense mutations are localized predominantly in the PDYN region coding for the dynorphin A (DynA) neuropeptide and lead to persistently elevated mutant peptide levels with neurotoxic properties. The main DynA target in the central nervous system is the kappa opioid receptor (KOR), a member of the G-protein coupled receptor family, which can elicit signaling cascades mediated by G-protein dissociation as well as β-arrestin recruitment. To date, a thorough analysis of the functional profile for the pathogenic SCA23 DynA mutants at KOR is still missing. To elucidate the role of DynA mutants, we used a combination of assays to investigate the differential activation of G-protein subunits and β-arrestin. In addition, we applied molecular modelling techniques to provide a rationale for the underlying mechanism. Our results demonstrate that DynA mutations, associated with a severe ataxic phenotype, decrease potency of KOR activation, both for G-protein dissociation as well as β-arrestin recruitment. Molecular modelling suggests that this loss of function is due to disruption of critical interactions between DynA and the receptor. In conclusion, this study advances our understanding of KOR signal transduction upon DynA wild type or mutant peptide binding.
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Kirby D, Parmar B, Fathi S, Marwah S, Nayak CR, Cherepanov V, MacParland S, Feld JJ, Altan-Bonnet G, Zilman A. Determinants of Ligand Specificity and Functional Plasticity in Type I Interferon Signaling. Front Immunol 2021; 12:748423. [PMID: 34691060 PMCID: PMC8529159 DOI: 10.3389/fimmu.2021.748423] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/14/2021] [Indexed: 11/13/2022] Open
Abstract
The Type I Interferon family of cytokines all act through the same cell surface receptor and induce phosphorylation of the same subset of response regulators of the STAT family. Despite their shared receptor, different Type I Interferons have different functions during immune response to infection. In particular, they differ in the potency of their induced anti-viral and anti-proliferative responses in target cells. It remains not fully understood how these functional differences can arise in a ligand-specific manner both at the level of STAT phosphorylation and the downstream function. We use a minimal computational model of Type I Interferon signaling, focusing on Interferon-α and Interferon-β. We validate the model with quantitative experimental data to identify the key determinants of specificity and functional plasticity in Type I Interferon signaling. We investigate different mechanisms of signal discrimination, and how multiple system components such as binding affinity, receptor expression levels and their variability, receptor internalization, short-term negative feedback by SOCS1 protein, and differential receptor expression play together to ensure ligand specificity on the level of STAT phosphorylation. Based on these results, we propose phenomenological functional mappings from STAT activation to downstream anti-viral and anti-proliferative activity to investigate differential signal processing steps downstream of STAT phosphorylation. We find that the negative feedback by the protein USP18, which enhances differences in signaling between Interferons via ligand-dependent refractoriness, can give rise to functional plasticity in Interferon-α and Interferon-β signaling, and explore other factors that control functional plasticity. Beyond Type I Interferon signaling, our results have a broad applicability to questions of signaling specificity and functional plasticity in signaling systems with multiple ligands acting through a bottleneck of a small number of shared receptors.
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Affiliation(s)
- Duncan Kirby
- Department of Physics, University of Toronto, Toronto, ON, Canada
| | - Baljyot Parmar
- Department of Physics, University of Toronto, Toronto, ON, Canada
| | - Sepehr Fathi
- Department of Physics, University of Toronto, Toronto, ON, Canada
| | - Sagar Marwah
- Ajmera Family Transplant Centre, Toronto General Research Institute, Departments of Laboratory Medicine and Pathobiology and Immunology, University of Toronto, Toronto, ON, Canada
| | - Chitra R Nayak
- Department of Physics, University of Toronto, Toronto, ON, Canada.,Department of Physics, Tuskegee University, Tuskegee, AL, United States
| | - Vera Cherepanov
- Sandra Rotman Centre for Global Health, Toronto General Research Institute, University of Toronto, Toronto, ON, Canada
| | - Sonya MacParland
- Ajmera Family Transplant Centre, Toronto General Research Institute, Departments of Laboratory Medicine and Pathobiology and Immunology, University of Toronto, Toronto, ON, Canada
| | - Jordan J Feld
- Toronto Centre for Liver Disease, University Health Network, Toronto, ON, Canada
| | - Grégoire Altan-Bonnet
- Immunodynamics Group, Laboratory of Integrative Cancer Immunology, Center for Cancer Research (CCR), National Cancer Institute (NCI), Bethesda, MD, United States
| | - Anton Zilman
- Department of Physics, University of Toronto, Toronto, ON, Canada.,Institute for Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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Jaszcza K, Scanes C, Capcarova M, Pierzchała-Koziec K. Effects of opioid and cholinergic receptors inhibition on the intestine hormones concentration and release in rats. JOURNAL OF ANIMAL AND FEED SCIENCES 2020. [DOI: 10.22358/jafs/126351/2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Abstract
Opioids, such as morphine and fentanyl, are widely used for the treatment of severe pain; however, prolonged treatment with these drugs leads to the development of tolerance and can lead to opioid use disorder. The "Opioid Epidemic" has generated a drive for a deeper understanding of the fundamental signaling mechanisms of opioid receptors. It is generally thought that the three types of opioid receptors (μ, δ, κ) are activated by endogenous peptides derived from three different precursors: Proopiomelanocortin, proenkephalin, and prodynorphin. Posttranslational processing of these precursors generates >20 peptides with opioid receptor activity, leading to a long-standing question of the significance of this repertoire of peptides. Here, we address some aspects of this question using a technical tour de force approach to systematically evaluate ligand binding and signaling properties ([35S]GTPγS binding and β-arrestin recruitment) of 22 peptides at each of the three opioid receptors. We show that nearly all tested peptides are able to activate the three opioid receptors, and many of them exhibit agonist-directed receptor signaling (functional selectivity). Our data also challenge the dogma that shorter forms of β-endorphin do not exhibit receptor activity; we show that they exhibit robust signaling in cultured cells and in an acute brain slice preparation. Collectively, this information lays the groundwork for improved understanding of the endogenous opioid system that will help in developing more effective treatments for pain and addiction.
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10
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Biased GPCR signaling: Possible mechanisms and inherent limitations. Pharmacol Ther 2020; 211:107540. [PMID: 32201315 DOI: 10.1016/j.pharmthera.2020.107540] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Accepted: 03/17/2020] [Indexed: 02/06/2023]
Abstract
G protein-coupled receptors (GPCRs) are targeted by about a third of clinically used drugs. Many GPCRs couple to more than one type of heterotrimeric G proteins, become phosphorylated by any of several different GRKs, and then bind one or more types of arrestin. Thus, classical therapeutically active drugs simultaneously initiate several branches of signaling, some of which are beneficial, whereas others result in unwanted on-target side effects. The development of novel compounds to selectively channel the signaling into the desired direction has the potential to become a breakthrough in health care. However, there are natural and technological hurdles that must be overcome. The fact that most GPCRs are subject to homologous desensitization, where the active receptor couples to G proteins, is phosphorylated by GRKs, and then binds arrestins, suggest that in most cases the GPCR conformations that facilitate their interactions with these three classes of binding partners significantly overlap. Thus, while partner-specific conformations might exist, they are likely low-probability states. GPCRs are inherently flexible, which suggests that complete bias is highly unlikely to be feasible: in the conformational ensemble induced by any ligand, there would be some conformations facilitating receptor coupling to unwanted partners. Things are further complicated by the fact that virtually every cell expresses numerous G proteins, several GRK subtypes, and two non-visual arrestins with distinct signaling capabilities. Finally, novel screening methods for measuring ligand bias must be devised, as the existing methods are not specific for one particular branch of signaling.
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Nassour H, Iddir M, Chatenet D. Towards Targeting the Urotensinergic System: Overview and Challenges. Trends Pharmacol Sci 2019; 40:725-734. [DOI: 10.1016/j.tips.2019.08.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 08/11/2019] [Accepted: 08/13/2019] [Indexed: 12/19/2022]
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12
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Carbone SE, Veldhuis NA, Gondin AB, Poole DP. G protein-coupled receptor trafficking and signaling: new insights into the enteric nervous system. Am J Physiol Gastrointest Liver Physiol 2019; 316:G446-G452. [PMID: 30702900 DOI: 10.1152/ajpgi.00406.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
G protein-coupled receptors (GPCRs) are essential for the neurogenic control of gastrointestinal (GI) function and are important and emerging therapeutic targets in the gut. Detailed knowledge of both the distribution and functional expression of GPCRs in the enteric nervous system (ENS) is critical toward advancing our understanding of how these receptors contribute to GI function during physiological and pathophysiological states. Equally important, but less well defined, is the complex relationship between receptor expression, ligand binding, signaling, and trafficking within enteric neurons. Neuronal GPCRs are internalized following exposure to agonists and under pathological conditions, such as intestinal inflammation. However, the relationship between the intracellular distribution of GPCRs and their signaling outputs in this setting remains a "black box". This review will briefly summarize current knowledge of agonist-evoked GPCR trafficking and location-specific signaling in the ENS and identifies key areas where future research could be focused. Greater understanding of the cellular and molecular mechanisms involved in regulating GPCR signaling in the ENS will provide new insights into GI function and may open novel avenues for therapeutic targeting of GPCRs for the treatment of digestive disorders.
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Affiliation(s)
- Simona E Carbone
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University , Parkville, Victoria , Australia
| | - Nicholas A Veldhuis
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University , Parkville, Victoria , Australia
| | - Arisbel B Gondin
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University , Parkville, Victoria , Australia
| | - Daniel P Poole
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences and Australian Research Council Centre of Excellence in Convergent Bio-Nano Science and Technology, Monash University , Parkville, Victoria , Australia.,Anatomy and Neuroscience, The University of Melbourne , Parkville, Victoria , Australia
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13
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Poujol de Molliens M, Létourneau M, Devost D, Hébert TE, Fournier A, Chatenet D. New insights about the peculiar role of the 28–38 C-terminal segment and some selected residues in PACAP for signaling and neuroprotection. Biochem Pharmacol 2018; 154:193-202. [DOI: 10.1016/j.bcp.2018.04.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 04/24/2018] [Indexed: 12/20/2022]
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14
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Billard É, Iddir M, Nassour H, Lee-Gosselin L, Poujol de Molliens M, Chatenet D. New directions for urotensin II receptor ligands. Pept Sci (Hoboken) 2018. [DOI: 10.1002/pep2.24056] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Étienne Billard
- INRS-Institut Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec; Ville de Laval Québec H7V 1B7 Canada
| | - Mustapha Iddir
- INRS-Institut Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec; Ville de Laval Québec H7V 1B7 Canada
| | - Hassan Nassour
- INRS-Institut Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec; Ville de Laval Québec H7V 1B7 Canada
| | - Laura Lee-Gosselin
- INRS-Institut Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec; Ville de Laval Québec H7V 1B7 Canada
| | - Mathilde Poujol de Molliens
- INRS-Institut Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec; Ville de Laval Québec H7V 1B7 Canada
| | - David Chatenet
- INRS-Institut Armand-Frappier, Groupe de Recherche en Ingénierie des Peptides et en Pharmacothérapie (GRIPP), Université du Québec; Ville de Laval Québec H7V 1B7 Canada
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Paternoster S, Falasca M. Dissecting the Physiology and Pathophysiology of Glucagon-Like Peptide-1. Front Endocrinol (Lausanne) 2018; 9:584. [PMID: 30364192 PMCID: PMC6193070 DOI: 10.3389/fendo.2018.00584] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/14/2018] [Indexed: 12/11/2022] Open
Abstract
An aging world population exposed to a sedentary life style is currently plagued by chronic metabolic diseases, such as type-2 diabetes, that are spreading worldwide at an unprecedented rate. One of the most promising pharmacological approaches for the management of type 2 diabetes takes advantage of the peptide hormone glucagon-like peptide-1 (GLP-1) under the form of protease resistant mimetics, and DPP-IV inhibitors. Despite the improved quality of life, long-term treatments with these new classes of drugs are riddled with serious and life-threatening side-effects, with no overall cure of the disease. New evidence is shedding more light over the complex physiology of GLP-1 in health and metabolic diseases. Herein, we discuss the most recent advancements in the biology of gut receptors known to induce the secretion of GLP-1, to bridge the multiple gaps into our understanding of its physiology and pathology.
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16
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Lay J, Carbone SE, DiCello JJ, Bunnett NW, Canals M, Poole DP. Distribution and trafficking of the μ-opioid receptor in enteric neurons of the guinea pig. Am J Physiol Gastrointest Liver Physiol 2016; 311:G252-66. [PMID: 27365337 DOI: 10.1152/ajpgi.00184.2016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 06/16/2016] [Indexed: 01/31/2023]
Abstract
The μ-opioid receptor (MOR) is a major regulator of gastrointestinal motility and secretion and mediates opiate-induced bowel dysfunction. Although MOR is of physiological and therapeutic importance to gut function, the cellular and subcellular distribution and regulation of MOR within the enteric nervous system are largely undefined. Herein, we defined the neurochemical coding of MOR-expressing neurons in the guinea pig gut and examined the effects of opioids on MOR trafficking and regulation. MOR expression was restricted to subsets of enteric neurons. In the stomach MOR was mainly localized to nitrergic neurons (∼88%), with some overlap with neuropeptide Y (NPY) and no expression by cholinergic neurons. These neurons are likely to have inhibitory motor and secretomotor functions. MOR was restricted to noncholinergic secretomotor neurons (VIP-positive) of the ileum and distal colon submucosal plexus. MOR was mainly detected in nitrergic neurons of the colon (nitric oxide synthase positive, 87%), with some overlap with choline acetyltransferase (ChAT). No expression of MOR by intrinsic sensory neurons was detected. [d-Ala(2), MePhe(4), Gly(ol)(5)]enkephalin (DAMGO), morphiceptin, and loperamide induced MOR endocytosis in myenteric neurons. After stimulation with DAMGO and morphiceptin, MOR recycled, whereas MOR was retained within endosomes following loperamide treatment. Herkinorin or the δ-opioid receptor agonist [d-Ala(2), d-Leu(5)]enkephalin (DADLE) did not evoke MOR endocytosis. In summary, we have identified the neurochemical coding of MOR-positive enteric neurons and have demonstrated differential trafficking of MOR in these neurons in response to established and putative MOR agonists.
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Affiliation(s)
- Joslyn Lay
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Simona E Carbone
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Jesse J DiCello
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Nigel W Bunnett
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia; Departments of Pharmacology and Therapeutics, The University of Melbourne, Parkville, Victoria, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Parkville, Victoria, Australia; and Department of Anaesthesia and Peri-operative Medicine, Monash University, Parkville, Victoria, Australia
| | - Meritxell Canals
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Parkville, Victoria, Australia; and
| | - Daniel P Poole
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia; Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia; ARC Centre of Excellence in Convergent Bio-Nano Science and Technology, Parkville, Victoria, Australia; and
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17
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Basso L, Boué J, Mahiddine K, Blanpied C, Robiou-du-Pont S, Vergnolle N, Deraison C, Dietrich G. Endogenous analgesia mediated by CD4(+) T lymphocytes is dependent on enkephalins in mice. J Neuroinflammation 2016; 13:132. [PMID: 27245576 PMCID: PMC4888630 DOI: 10.1186/s12974-016-0591-x] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 05/20/2016] [Indexed: 12/31/2022] Open
Abstract
Background T cell-derived opioids play a key role in the control of inflammatory pain. However, the nature of opioids produced by T cells is still matter of debate in mice. Whereas β-endorphin has been found in T lymphocytes by using antibody-based methods, messenger RNA (mRNA) quantification shows mainly mRNA encoding for enkephalins. The objective of the study is to elucidate the nature of T cell-derived opioids responsible for analgesia and clarify discrepancy of the results at the protein and genetic levels. Methods CD4+ T lymphocytes were isolated from wild-type and enkephalin-deficient mice. mRNA encoding for β-endorphin and enkephalin was quantified by RT-qPCR. The binding of commercially available polyclonal anti-endorphin antibodies to lymphocytes from wild-type or enkephalin knockout mice was assessed by cytofluorometry. Opioid-mediated analgesic properties of T lymphocytes from wild-type and enkephalin-deficient mice were compared in a model of inflammation-induced somatic pain by measuring sensitivity to mechanical stimuli using calibrated von Frey filaments. Results CD4+ T lymphocytes expressed high level of mRNA encoding for enkephalins but not for β-endorphin in mice. Anti-β-endorphin polyclonal IgG antibodies are specific for β-endorphin but cross-react with enkephalins. Anti-β-endorphin polyclonal antibodies bound to wild-type but not enkephalin-deficient CD4+ T lymphocytes. Endogenous regulation of inflammatory pain by wild-type T lymphocytes was completely abolished when T lymphocytes were deficient in enkephalins. Pain behavior of immune-deficient (i.e., without B and T lymphocytes) mice was superimposable to that of mice transferred with enkephalin-deficient lymphocytes. Conclusions Rabbit polyclonal anti-β-endorphin serum IgG bind to CD4+ T lymphocytes because of their cross-reactivity towards enkephalins. Thus, staining of T lymphocytes by anti-β-endorphin polyclonal IgG reported in most of studies in mice is because of their binding to enkephalins. In mice, CD4+ T lymphocytes completely lose their analgesic opioid-mediated activity when lacking enkephalins.
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Affiliation(s)
- Lilian Basso
- IRSD, Université de Toulouse, INSERM, INRA, ENVT, UPS, Toulouse, France
| | - Jérôme Boué
- IRSD, Université de Toulouse, INSERM, INRA, ENVT, UPS, Toulouse, France
| | - Karim Mahiddine
- CPTP, Université de Toulouse, CNRS, INSERM, UPS, Toulouse, France
| | | | | | | | - Céline Deraison
- IRSD, Université de Toulouse, INSERM, INRA, ENVT, UPS, Toulouse, France
| | - Gilles Dietrich
- IRSD, Université de Toulouse, INSERM, INRA, ENVT, UPS, Toulouse, France.
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18
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Griggs DW, Prinsen MJ, Oliva J, Campbell MA, Arnett SD, Tajfirouz D, Ruminski PG, Yu Y, Bond BR, Ji Y, Neckermann G, Choy RKM, de Hostos E, Meyers MJ. Pharmacologic Comparison of Clinical Neutral Endopeptidase Inhibitors in a Rat Model of Acute Secretory Diarrhea. J Pharmacol Exp Ther 2016; 357:423-31. [PMID: 26907621 PMCID: PMC4851326 DOI: 10.1124/jpet.115.231167] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 02/17/2016] [Indexed: 12/15/2022] Open
Abstract
Racecadotril (acetorphan) is a neutral endopeptidase (NEP) inhibitor with known antidiarrheal activity in animals and humans; however, in humans, it suffers from shortcomings that might be improved with newer drugs in this class that have progressed to the clinic for nonenteric disease indications. To identify potentially superior NEP inhibitors with immediate clinical utility for diarrhea treatment, we compared their efficacy and pharmacologic properties in a rat intestinal hypersecretion model. Racecadotril and seven other clinical-stage inhibitors of NEP were obtained or synthesized. Enzyme potency and specificity were compared using purified peptidases. Compounds were orally administered to rats before administration of castor oil to induce diarrhea. Stool weight was recorded over 4 hours. To assess other pharmacologic properties, select compounds were orally administered to normal or castor oil–treated rats, blood and tissue samples collected at multiple time points, and active compound concentrations determined by mass spectroscopy. NEP enzyme activity was measured in tissue homogenates. Three previously untested clinical NEP inhibitors delayed diarrhea onset and reduced total stool output, with little or no effect on intestinal motility assessed by the charcoal meal test. Each was shown to be a potent, highly specific inhibitor of NEP. Each exhibited greater suppression of NEP activity in intestinal and nonintestinal tissues than did racecadotril and sustained this inhibition longer. These results suggest that newer clinical-stage NEP inhibitors originally developed for other indications may be directly repositioned for treatment of acute secretory diarrhea and offer advantages over racecadotril, such as less frequent dosing and potentially improved efficacy.
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Affiliation(s)
- David W Griggs
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Michael J Prinsen
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Jonathan Oliva
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Mary A Campbell
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Stacy D Arnett
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Deena Tajfirouz
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Peter G Ruminski
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Ying Yu
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Brian R Bond
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Yuhua Ji
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Georg Neckermann
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Robert K M Choy
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Eugenio de Hostos
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
| | - Marvin J Meyers
- Center for World Health and Medicine, Saint Louis University, St. Louis, Missouri (D.W.G, M.J.P, J.O., M.A.C., S.D.A., D.T., P.G.R., M.J.M); Gateway Pharmacology Laboratories, St. Louis, Missouri (Y.Y, B.B); and PATH, San Francisco, California (Y.J., G.N., R.K.M.C, E.dH.)
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19
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Prihandoko R, Alvarez-Curto E, Hudson BD, Butcher AJ, Ulven T, Miller AM, Tobin AB, Milligan G. Distinct Phosphorylation Clusters Determine the Signaling Outcome of Free Fatty Acid Receptor 4/G Protein–Coupled Receptor 120. Mol Pharmacol 2016; 89:505-20. [DOI: 10.1124/mol.115.101949] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/11/2016] [Indexed: 12/27/2022] Open
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20
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Mosińska P, Zielińska M, Fichna J. Expression and physiology of opioid receptors in the gastrointestinal tract. Curr Opin Endocrinol Diabetes Obes 2016; 23:3-10. [PMID: 26702845 DOI: 10.1097/med.0000000000000219] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
PURPOSE OF REVIEW Stimulation of opioid receptors elicits analgesic effect not only in the central nervous system, but also in the gastrointestinal tract, where a high concentration of opioid receptors can be found within the enteric nervous system as well as muscular and immune cells. Along with antinociception, opioid receptors in the stomach and intestine relay signals crucial for secretory and motor gastrointestinal function. RECENT FINDINGS The review focuses on the utility of opioid receptor antagonists, which is generally contributing to the management of postoperative ileus and opioid bowel dysfunction in chronic pain patients nonetheless, opioid receptor antagonists can also be useful in the treatment of irritable bowel syndrome and chronic idiopathic constipation. The study also discusses several antidiarrheal opioid agonists, as well as opioids and opioid mimetics encompassing the concept of ligand-biased agonism and truncated opioid receptor splice variants. SUMMARY Good understanding of the localization and the role of opioid receptors is vital for regulation of various pathophysiological processes in the gastrointestinal tract and may simultaneously provide a tempting approach in eliminating adverse effects related to centrally acting opioids.
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Affiliation(s)
- Paula Mosińska
- Department of Biochemistry, Faculty of Medicine, Medical University of Lodz, Lodz, Poland
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21
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Amarandi RM, Hjortø GM, Rosenkilde MM, Karlshøj S. Probing Biased Signaling in Chemokine Receptors. Methods Enzymol 2015; 570:155-86. [PMID: 26921946 DOI: 10.1016/bs.mie.2015.09.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The chemokine system mediates leukocyte migration during homeostatic and inflammatory processes. Traditionally, it is described as redundant and promiscuous, with a single chemokine ligand binding to different receptors and a single receptor having several ligands. Signaling of chemokine receptors occurs via two major routes, G protein- and β-arrestin-dependent, which can be preferentially modulated depending on the ligands or receptors involved, as well as the cell types or tissues in which the signaling event occurs. The preferential activation of a certain signaling pathway to the detriment of others has been termed signaling bias and can accordingly be grouped into ligand bias, receptor bias, and tissue bias. Bias has so far been broadly overlooked in the process of drug development. The low number of currently approved drugs targeting the chemokine system, as well as the broad range of failed clinical trials, reflects the need for a better understanding of the chemokine system. Thus, understanding the character, direction, and consequence of biased signaling in the chemokine system may aid the development of new therapeutics. This review describes experiments to assess G protein-dependent and -independent signaling in order to quantify chemokine system bias.
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Affiliation(s)
- Roxana-Maria Amarandi
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark; Faculty of Chemistry, Alexandru Ioan Cuza University of Iaşi, Iaşi, Romania
| | - Gertrud Malene Hjortø
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Mette Marie Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Stefanie Karlshøj
- Laboratory for Molecular Pharmacology, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute, University of Copenhagen, Copenhagen, Denmark.
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Receptor, Ligand and Transducer Contributions to Dopamine D2 Receptor Functional Selectivity. PLoS One 2015; 10:e0141637. [PMID: 26516769 PMCID: PMC4627803 DOI: 10.1371/journal.pone.0141637] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/12/2015] [Indexed: 12/20/2022] Open
Abstract
Functional selectivity (or biased agonism) is a property exhibited by some G protein-coupled receptor (GPCR) ligands, which results in the modulation of a subset of a receptor's signaling capabilities and more precise control over complex biological processes. The dopamine D2 receptor (D2R) exhibits pleiotropic responses to the biogenic amine dopamine (DA) to mediate complex central nervous system functions through activation of G proteins and β-arrestins. D2R is a prominent therapeutic target for psychological and neurological disorders in which DA biology is dysregulated and targeting D2R with functionally selective drugs could provide a means by which pharmacotherapies could be developed. However, factors that determine GPCR functional selectivity in vivo may be multiple with receptors, ligands and transducers contributing to the process. We have recently described a mutagenesis approach to engineer biased D2R mutants in which G protein-dependent ([Gprot]D2R) and β-arrestin-dependent signaling ([βarr]D2R) were successfully separated (Peterson, et al. PNAS, 2015). Here, permutations of these mutants were used to identify critical determinants of the D2R signaling complex that impart signaling bias in response to the natural or synthetic ligands. Critical residues identified in generating [Gprot]D2R and [βarr]D2R conferred control of partial agonism at G protein and/or β-arrestin activity. Another set of mutations that result in G protein bias was identified that demonstrated that full agonists can impart unique activation patterns, and provided further credence to the concept of ligand texture. Finally, the contributions and interplay between different transducers indicated that G proteins are not aberrantly activated, and that receptor kinase and β-arrestin activities are inextricably linked. These data provide a thorough elucidation of the feasibility and malleability of D2R functional selectivity and point to means by which novel in vivo therapies could be modeled.
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23
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Massotte D. Editorial: Monitoring endogenous GPCRs: lessons for drug design. Front Pharmacol 2015; 6:146. [PMID: 26236238 PMCID: PMC4500908 DOI: 10.3389/fphar.2015.00146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 07/01/2015] [Indexed: 12/02/2022] Open
Affiliation(s)
- Dominique Massotte
- Institut des Neurosciences Cellulaires et Intégratives Strasbourg, France
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Shang Y, Filizola M. Opioid receptors: Structural and mechanistic insights into pharmacology and signaling. Eur J Pharmacol 2015; 763:206-13. [PMID: 25981301 DOI: 10.1016/j.ejphar.2015.05.012] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Revised: 03/02/2015] [Accepted: 05/11/2015] [Indexed: 01/18/2023]
Abstract
Opioid receptors are important drug targets for pain management, addiction, and mood disorders. Although substantial research on these important subtypes of G protein-coupled receptors has been conducted over the past two decades to discover ligands with higher specificity and diminished side effects, currently used opioid therapeutics remain suboptimal. Luckily, recent advances in structural biology of opioid receptors provide unprecedented insights into opioid receptor pharmacology and signaling. We review here a few recent studies that have used the crystal structures of opioid receptors as a basis for revealing mechanistic details of signal transduction mediated by these receptors, and for the purpose of drug discovery.
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Affiliation(s)
- Yi Shang
- Icahn School of Medicine at Mount Sinai, Department of Structural and Chemical Biology, One Gustave, L. Levy Place, Box 1677, New York, NY 10029, USA
| | - Marta Filizola
- Icahn School of Medicine at Mount Sinai, Department of Structural and Chemical Biology, One Gustave, L. Levy Place, Box 1677, New York, NY 10029, USA.
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