1
|
Misery L, Pierre O, Le Gall-Ianotto C, Lebonvallet N, Chernyshov PV, Le Garrec R, Talagas M. Basic mechanisms of itch. J Allergy Clin Immunol 2023; 152:11-23. [PMID: 37201903 DOI: 10.1016/j.jaci.2023.05.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/02/2023] [Accepted: 05/11/2023] [Indexed: 05/20/2023]
Abstract
Pruritus (or itch) is an unpleasant sensation leading to a desire to scratch. In the epidermis, there are selective C or Aδ epidermal nerve endings that are pruriceptors. At their other ends, peripheral neurons form synapses with spinal neurons and interneurons. Many areas in the central nervous system are involved in itch processing. Although itch does not occur solely because of parasitic, allergic, or immunologic diseases, it is usually the consequence of neuroimmune interactions. Histamine is involved in a minority of itchy conditions, and many other mediators play a role: cytokines (eg, IL-4, IL-13, IL-31, IL-33, and thymic stromal lymphopoietin), neurotransmitters (eg, substance P, calcitonin gene-related peptide, vasoactive intestinal peptide, neuropeptide Y, NBNP, endothelin 1, and gastrin-releasing peptide), and neurotrophins (eg, nerve growth factor and brain-derived neurotrophic factor). Moreover, ion channels such as voltage-gated sodium channels, transient receptor potential vanilloid 1, transient receptor ankyrin, and transient receptor potential cation channel subfamily M (melastatin) member 8 play a crucial role. The main markers of nonhistaminergic pruriceptors are PAR-2 and MrgprX2. A notable phenomenon is the sensitization to pruritus, in which regardless of the initial cause of pruritus, there is an increased responsiveness of peripheral and central pruriceptive neurons to their normal or subthreshold afferent input in the context of chronic itch.
Collapse
Affiliation(s)
- Laurent Misery
- Laboratoire Interactions Neurones-Keratinocytes (LINK), University of Brest, Brest, France; Department of Dermatology and Venereology, University Hospital of Brest, Brest, France.
| | - Ophélie Pierre
- Laboratoire Interactions Neurones-Keratinocytes (LINK), University of Brest, Brest, France
| | - Christelle Le Gall-Ianotto
- Laboratoire Interactions Neurones-Keratinocytes (LINK), University of Brest, Brest, France; Department of Dermatology and Venereology, University Hospital of Brest, Brest, France
| | - Nicolas Lebonvallet
- Laboratoire Interactions Neurones-Keratinocytes (LINK), University of Brest, Brest, France
| | - Pavel V Chernyshov
- Department of Dermatology and Venereology, National Medical University, Kiev, Ukraine
| | - Raphaële Le Garrec
- Laboratoire Interactions Neurones-Keratinocytes (LINK), University of Brest, Brest, France
| | - Matthieu Talagas
- Laboratoire Interactions Neurones-Keratinocytes (LINK), University of Brest, Brest, France; Department of Dermatology and Venereology, University Hospital of Brest, Brest, France
| |
Collapse
|
2
|
Yu J, Hou B, Huang Y, Wang X, Qian Y, Liang Y, Gu X, Ma Z, Sun Y. USP48 alleviates bone cancer pain and regulates MrgC stabilization in spinal cord neurons of male mice. Eur J Pain 2023. [PMID: 36864656 DOI: 10.1002/ejp.2102] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 02/19/2023] [Accepted: 02/21/2023] [Indexed: 03/04/2023]
Abstract
BACKGROUND Ubiquitin-mediated degradation of the Mas-related G protein-coupled receptor C (MrgC) reduces the number of receptors. However, the specific deubiquitinating enzyme antagonize this process has not been reported. In this study, we investigated the effect of ubiquitin-specific protease-48 (USP48) on bone cancer pain (BCP) and its effect on MrgC. METHODS A mouse model of BCP was established. BCP behaviours of mice were assessed after intrathecal injection of adeno-associated virus (AAV)-USP48. USP48 and MrgC interactions were studied by immunoprecipitation. Overexpression and knockdown of USP48 were conducted in N2a cells to investigate the effect of USP48 on MrgC receptor number and ubiquitination. RESULTS Spinal cord level USP48 expression was reduced in mice with BCP. Intrathecal injection of AAV-USP48 increased paw withdrawal mechanical threshold and reduced spontaneous flinching in mice. In N2a cells, there were increased number of MrgC receptors after overexpression of USP48 and decreased number of MrgC receptors after knockdown of USP48. USP48 interacted with MrgC and overexpression of USP48 altered the level of ubiquitination of MrgC. CONCLUSION USP48 antagonizes ubiquitin-mediated autophagic degradation of MrgC and alleviates BCP in a murine animal model. Our findings may provide a new perspective for the treatment of BCP. SIGNIFICANCE Our finding may provide an important theoretical basis as well as an intervention target for clinical development of drugs for BCP.
Collapse
Affiliation(s)
- Jiacheng Yu
- Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Bailing Hou
- Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Yulin Huang
- Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Xiaoyu Wang
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Yue Qian
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Ying Liang
- Department of Anesthesiology, Nanjing Drum Tower Hospital, Medical School of Nanjing University, Nanjing, China
| | - Xiaoping Gu
- Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Zhengliang Ma
- Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Yue Sun
- Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| |
Collapse
|
3
|
Guo S, Jansen-Olesen I, Olesen J, Christensen SL. Role of PACAP in migraine: An alternative to CGRP? Neurobiol Dis 2023; 176:105946. [PMID: 36481434 DOI: 10.1016/j.nbd.2022.105946] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 11/29/2022] [Accepted: 12/03/2022] [Indexed: 12/12/2022] Open
Abstract
Migraine is a widespread and debilitating neurological condition affecting more than a billion people worldwide. Thus, more effective migraine therapies are highly needed. In the last decade, two endogenous neuropeptides, calcitonin gene-related peptide (CGRP) and pituitary adenylate cyclase-activating peptide (PACAP), were identified to be implicated in migraine. Recently, introduction of monoclonal antibodies (mAbs) blocking the CGRP is the most important advance in migraine therapy for decades. However, 40% of patients are unresponsive to these new drugs. We believe that PACAP may be involved in these patients. Like CGRP, PACAP is located to sensory nerve fibers, it dilates cranial arteries, it causes migraine when infused into patients and it is a peptide that lends itself to antibody therapy. Also, recent studies suggest that the PACAP pathway is independent of the CGRP pathway. Understanding the signaling pathways of PACAP may therefore lead to identification of novel therapeutic targets of particular interest in patients unresponsive to anti-CGRP therapy. Accordingly, neutralizing mAb to PACAP is currently in clinical phase II development. The aim of the present review is, therefore, to give a thorough account of the existing data on PACAP, its receptors and its relation to migraine.
Collapse
Affiliation(s)
- Song Guo
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Inger Jansen-Olesen
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Jes Olesen
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark
| | - Sarah Louise Christensen
- Department of Neurology, Danish Headache Center, Copenhagen University Hospital - Rigshospitalet, Copenhagen, Denmark.
| |
Collapse
|
4
|
Ryu K, Heo Y, Lee Y, Jeon H, Namkung W. Berbamine Reduces Chloroquine-Induced Itch in Mice through Inhibition of MrgprX1. Int J Mol Sci 2022; 23:ijms232214321. [PMID: 36430803 PMCID: PMC9698483 DOI: 10.3390/ijms232214321] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 11/14/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Chloroquine (CQ) is an antimalaria drug that has been widely used for decades. However, CQ-induced pruritus remains one of the major obstacles in CQ treatment for uncomplicated malaria. Recent studies have revealed that MrgprX1 plays an essential role in CQ-induced itch. To date, a few MrgprX1 antagonists have been discovered, but they are clinically unavailable or lack selectivity. Here, a cell-based high-throughput screening was performed to identify novel antagonists of MrgprX1, and the screening of 2543 compounds revealed two novel MrgprX1 inhibitors, berbamine and closantel. Notably, berbamine potently inhibited CQ-mediated MrgprX1 activation (IC50 = 1.6 μM) but did not alter the activity of other pruritogenic GPCRs. In addition, berbamine suppressed the CQ-mediated phosphorylation of ERK1/2. Interestingly, CQ-induced pruritus was significantly reduced by berbamine in a dose-dependent manner, but berbamine had no effect on histamine-induced, protease-activated receptors 2-activating peptide-induced, and deoxycholic acid-induced itch in mice. These results suggest that berbamine is a novel, potent, and selective antagonist of MrgprX1 and may be a potential drug candidate for the development of therapeutic agents to treat CQ-induced pruritus.
Collapse
|
5
|
MAS-related G protein-coupled receptors X (MRGPRX): Orphan GPCRs with potential as targets for future drugs. Pharmacol Ther 2022; 238:108259. [DOI: 10.1016/j.pharmthera.2022.108259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Revised: 07/30/2022] [Accepted: 08/01/2022] [Indexed: 11/20/2022]
|
6
|
Mas-Related G Protein-Coupled Receptors (Mrgprs) as Mediators of Gut Neuro-Immune Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1383:259-269. [PMID: 36587165 DOI: 10.1007/978-3-031-05843-1_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Over the past 15 years, the research field on Mas-related G protein-coupled receptors (Mrgprs), a relatively new family of rhodopsin A-like G protein-coupled receptors, has expanded enormously, and a plethora of recent studies have provided evidence that several of these Mrgpr family members play an important role in the underlying mechanisms of itch and pain, as well as in the initiation and modulation of inflammatory/allergic responses. Initial studies mainly focused on the skin, but more recently also visceral organs such as the respiratory and gastrointestinal (GI) tracts emerged as sites for Mrgpr involvement. It has become clear that the gastrointestinal tract and its innervation in close association with the immune system represent a novel expression site for Mrgprs where they contribute to the interoceptive mechanisms maintaining homeostasis and might constitute promising targets in chronic abdominal pain disorders. In this short review, we provide an update of our current knowledge on the expression, distribution, and function of members of this Mrgpr family in intrinsic and extrinsic neuro-immune pathways related to the gastrointestinal tract, their mediatory role(s) in gut neuro-immune signaling, and their involvement in visceral afferent (nociceptive) pathways.
Collapse
|
7
|
Palmer CB, Meyrath M, Canals M, Kostenis E, Chevigné A, Szpakowska M. Atypical opioid receptors: unconventional biology and therapeutic opportunities. Pharmacol Ther 2021; 233:108014. [PMID: 34624426 DOI: 10.1016/j.pharmthera.2021.108014] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 09/13/2021] [Accepted: 09/27/2021] [Indexed: 12/13/2022]
Abstract
Endogenous opioid peptides and prescription opioid drugs modulate pain, anxiety and stress by activating four opioid receptors, namely μ (mu, MOP), δ (delta, DOP), κ (kappa, KOP) and the nociceptin/orphanin FQ receptor (NOP). Interestingly, several other receptors are also activated by endogenous opioid peptides and influence opioid-driven signaling and biology. However, they do not meet the criteria to be recognized as classical opioid receptors, as they are phylogenetically distant from them and are insensitive to classical non-selective opioid receptor antagonists (e.g. naloxone). Nevertheless, accumulating reports suggest that these receptors may be interesting alternative targets, especially for the development of safer analgesics. Five of these opioid peptide-binding receptors belong to the family of G protein-coupled receptors (GPCRs)-two are members of the Mas-related G protein-coupled receptor X family (MrgX1, MrgX2), two of the bradykinin receptor family (B1, B2), and one is an atypical chemokine receptor (ACKR3). Additionally, the ion channel N-methyl-d-aspartate receptors (NMDARs) are also activated by opioid peptides. In this review, we recapitulate the implication of these alternative receptors in opioid-related disorders and discuss their unconventional biology, with members displaying signaling to scavenging properties. We provide an overview of their established and emerging roles and pharmacology in the context of pain management, as well as their clinical relevance as alternative targets to overcome the hurdles of chronic opioid use. Given the involvement of these receptors in a wide variety of functions, including inflammation, chemotaxis, anaphylaxis or synaptic transmission and plasticity, we also discuss the challenges associated with the modulation of both their canonical and opioid-driven signaling.
Collapse
Affiliation(s)
- Christie B Palmer
- Immuno-Pharmacology and Interactomics, Department of Infection and Immunity, Luxembourg Institute of Health (LIH), Esch-sur-Alzette, Luxembourg; Faculty of Science, Technology and Medicine, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Max Meyrath
- Immuno-Pharmacology and Interactomics, Department of Infection and Immunity, Luxembourg Institute of Health (LIH), Esch-sur-Alzette, Luxembourg
| | - Meritxell Canals
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK; Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, UK
| | - Evi Kostenis
- Molecular, Cellular and Pharmacobiology Section, Institute for Pharmaceutical Biology, University of Bonn, Bonn, Germany
| | - Andy Chevigné
- Immuno-Pharmacology and Interactomics, Department of Infection and Immunity, Luxembourg Institute of Health (LIH), Esch-sur-Alzette, Luxembourg.
| | - Martyna Szpakowska
- Immuno-Pharmacology and Interactomics, Department of Infection and Immunity, Luxembourg Institute of Health (LIH), Esch-sur-Alzette, Luxembourg
| |
Collapse
|
8
|
Nagakura Y, Nagaoka S, Kurose T. Potential Molecular Targets for Treating Neuropathic Orofacial Pain Based on Current Findings in Animal Models. Int J Mol Sci 2021; 22:ijms22126406. [PMID: 34203854 PMCID: PMC8232571 DOI: 10.3390/ijms22126406] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/11/2021] [Accepted: 06/13/2021] [Indexed: 01/25/2023] Open
Abstract
This review highlights potential molecular targets for treating neuropathic orofacial pain based on current findings in animal models. Preclinical research is currently elucidating the pathophysiology of the disease and identifying the molecular targets for better therapies using animal models that mimic this category of orofacial pain, especially post-traumatic trigeminal neuropathic pain (PTNP) and primary trigeminal neuralgia (PTN). Animal models of PTNP and PTN simulate their etiologies, that is, trauma to the trigeminal nerve branch and compression of the trigeminal root entry zone, respectively. Investigations in these animal models have suggested that biological processes, including inflammation, enhanced neuropeptide-mediated pain signal transmission, axonal ectopic discharges, and enhancement of interactions between neurons and glial cells in the trigeminal pathway, are underlying orofacial pain phenotypes. The molecules associated with biological processes, whose expressions are substantially altered following trigeminal nerve damage or compression of the trigeminal nerve root, are potentially involved in the generation and/or exacerbation of neuropathic orofacial pain and can be potential molecular targets for the discovery of better therapies. Application of therapeutic candidates, which act on the molecular targets and modulate biological processes, attenuates pain-associated behaviors in animal models. Such therapeutic candidates including calcitonin gene-related peptide receptor antagonists that have a reasonable mechanism for ameliorating neuropathic orofacial pain and meet the requirements for safe administration to humans seem worth to be evaluated in clinical trials. Such prospective translation of the efficacy of therapeutic candidates from animal models to human patients would help develop better therapies for neuropathic orofacial pain.
Collapse
Affiliation(s)
- Yukinori Nagakura
- School of Pharmacy at Fukuoka, International University of Health and Welfare, 137-1 Enokizu, Okawa-city, Fukuoka 831-8501, Japan
- Correspondence:
| | - Shogo Nagaoka
- Basic Research Development Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan; (S.N.); (T.K.)
| | - Takahiro Kurose
- Basic Research Development Division, Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa, Kyoto 619-0216, Japan; (S.N.); (T.K.)
| |
Collapse
|
9
|
McMillan H, Lundy FT, Dunne OM, Al-Natour B, Jeanneau C, About I, Curtis TM, El Karim I. Endogenous Mas-related G-protein-coupled receptor X1 activates and sensitizes TRPA1 in a human model of peripheral nerves. FASEB J 2021; 35:e21492. [PMID: 33788969 DOI: 10.1096/fj.202001667rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 02/16/2021] [Accepted: 02/16/2021] [Indexed: 12/21/2022]
Abstract
Mas-related G-protein-coupled receptor X1 (MrgprX1) is a human-specific Mrgpr and its expression is restricted to primary sensory neurons. However, its role in nociception and pain signaling pathways is largely unknown. This study aims to investigate a role for MrgprX1 in nociception via interaction with the pain receptor, Transient Receptor Potential Ankyrin 1 (TRPA1), using in-vitro and in-vivo human neuronal models. MrgprX1 protein expression in human trigeminal nociceptors was investigated by the immunolabeling of the dental pulp and cultured peripheral neuronal equivalent (PNE) cells. MrgprX1 receptor signaling was monitored by Fura-2-based Ca2+ imaging using PNEs and membrane potential responses were measured using FluoVoltTM . Immunofluorescent staining revealed MrgprX1 expression in-vivo in dental afferents, which was more intense in inflamed compared to healthy dental pulps. Endogenous MrgprX1 protein expression was confirmed in the in-vitro human PNE model. MrgprX1 receptor signaling and the mechanisms through which it couples to TRPA1 were studied by Ca2+ imaging. Results showed that MrgprX1 activates TRPA1 and induces membrane depolarization in a TRPA1 dependent manner. In addition, MrgprX1 sensitizes TRPA1 to agonist stimulation via Protein Kinase C (PKC). The activation and sensitization of TRPA1 by MrgprX1 in a model of human nerves suggests an important role for this receptor in the modulation of nociception.
Collapse
Affiliation(s)
- Hayley McMillan
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, UK
| | - Fionnuala T Lundy
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, UK
| | - Orla M Dunne
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, UK
| | - Banan Al-Natour
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, UK
- Department of Oral Medicine and Oral Surgery, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan
| | | | - Imad About
- Aix Marseille Univ, CNRS, ISM, Inst Movement Sci, Marseille, France
| | - Tim M Curtis
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, UK
| | - Ikhlas El Karim
- School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, UK
| |
Collapse
|
10
|
Huang Q, Ford NC, Gao X, Chen Z, Guo R, Raja SN, Guan Y, He S. Ubiquitin-mediated receptor degradation contributes to development of tolerance to MrgC agonist-induced pain inhibition in neuropathic rats. Pain 2021; 162:1082-1094. [PMID: 33110031 PMCID: PMC7969388 DOI: 10.1097/j.pain.0000000000002119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 10/15/2020] [Indexed: 11/25/2022]
Abstract
ABSTRACT Agonists to subtype C of the Mas-related G-protein-coupled receptors (MrgC) induce pain inhibition after intrathecal (i.t.) administration in rodent models of nerve injury. Here, we investigated whether tolerance develops after repeated MrgC agonist treatments and examined the underlying mechanisms. In animal behavior studies conducted in male rats at 4 to 5 weeks after an L5 spinal nerve ligation (SNL), the ability of dipeptide MrgC agonist JHU58 (0.1 mM, 10 μL, i.t.) to inhibit mechanical and heat hypersensitivity decreased after 3 days of treatment with a tolerance-inducing dose (0.5 mM, 10 μL, i.t., twice/day). In HEK293T cells, acute treatment with JHU58 or BAM8-22 (a large peptide MrgC agonist) led to MrgC endocytosis from the cell membrane and later sorting to the membrane for reinsertion. However, chronic exposure to JHU58 increased the coupling of MrgC to β-arrestin-2 and led to the ubiquitination and degradation of MrgC. Importantly, pretreatment with TAK-243 (0.2 mM, 5 μL, i.t.), a small-molecule inhibitor of the ubiquitin-activating enzyme, during tolerance induction attenuated the development of tolerance to JHU58-induced inhibition of mechanical and heat hypersensitivity in SNL rats. Interestingly, morphine analgesia was also decreased in SNL rats that had become tolerant to JHU58, suggesting a cross-tolerance. Furthermore, i.t. pretreatment with TAK-243, which reduced JHU58 tolerance, also attenuated the cross-tolerance to morphine analgesia. These findings suggest that tolerance can develop to MrgC agonist-induced pain inhibition after repeated i.t. administrations. This tolerance development to JHU58 may involve increased coupling of MrgC to β-arrestin-2 and ubiquitin-mediated receptor degradation.
Collapse
Affiliation(s)
- Qian Huang
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Neil C. Ford
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Xinyan Gao
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Zhiyong Chen
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Ruijuan Guo
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Srinivasa N. Raja
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Department of Neurological Surgery, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Shaoqiu He
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| |
Collapse
|
11
|
Steele HR, Han L. The signaling pathway and polymorphisms of Mrgprs. Neurosci Lett 2020; 744:135562. [PMID: 33388356 DOI: 10.1016/j.neulet.2020.135562] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Revised: 12/02/2020] [Accepted: 12/08/2020] [Indexed: 12/31/2022]
Abstract
Mas-related G protein-coupled receptors (Mrgprs) are a family of receptors implicated in a diverse array of human diseases. Since their discovery in 2001, great progress has been made in determining their relation to human disease. Vital for Mrgprs therapeutic efforts across all disease disciplines is a thorough understanding of Mrgprs signal transduction pathways and polymorphisms, as these offer insights into new drug candidates, existing discrepancies in drug response, and differences in disease susceptibility. In this review, we discuss the current state of knowledge regarding Mrgprs signaling pathways and polymorphisms.
Collapse
Affiliation(s)
- Haley R Steele
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States
| | - Liang Han
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, GA, United States.
| |
Collapse
|
12
|
Tiwari V, He SQ, Huang Q, Liang L, Yang F, Chen Z, Tiwari V, Fujita W, Devi LA, Dong X, Guan Y, Raja SN. Activation of µ-δ opioid receptor heteromers inhibits neuropathic pain behavior in rodents. Pain 2020; 161:842-855. [PMID: 31815916 PMCID: PMC7085422 DOI: 10.1097/j.pain.0000000000001768] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Several reports support the idea that µ- and δ-opioid receptors (ORs) may exist as heterodimers in brain regions involved in pain signaling. The unique pharmacology of these heteromers may present a novel analgesic target. However, the role of µ-δ heteromers in sensory neurons involved in pain and opioid analgesia remains unclear, particularly during neuropathic pain. We examined the effects of spinal nerve injury on µ-δ heteromer expression in dorsal root ganglion (DRG) neurons and the effects of a µ-δ heteromer-targeting agonist, CYM51010, on neuropathic pain behavior in rats and mice. An L5 spinal nerve ligation (SNL) in rats significantly decreased µ-δ heteromer expression in L5 DRG but increased heteromer levels in uninjured L4 DRG. Importantly, in SNL rats, subcutaneous injection of CYM51010 inhibited mechanical hypersensitivity in a dose-related manner (EC50: 1.09 mg/kg) and also reversed heat hyperalgesia and attenuated ongoing pain (2 mg/kg, subcutaneously). HEK-293T cell surface-labeled with µ- and δ-ORs internalized both receptors after exposure to CYM51010. By contrast, in cells transfected with µ-OR alone, CYM51010 was significantly less effective at inducing receptor internalization. Electrophysiologic studies showed that CYM51010 inhibited the C-component and windup phenomenon in spinal wide dynamic range neurons of SNL rats. The pain inhibitory effects of CYM51010 persisted in morphine-tolerant rats but was markedly attenuated in µ-OR knockout mice. Our studies show that spinal nerve injury may increase µ-δ heterodimerization in uninjured DRG neurons, and that µ-δ heteromers may be a potential therapeutic target for relieving neuropathic pain, even under conditions of morphine tolerance.
Collapse
Affiliation(s)
- Vinod Tiwari
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Qian Huang
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Lingli Liang
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Zhiyong Chen
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Vineeta Tiwari
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Wakako Fujita
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Lakshmi A. Devi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Howard Hughes Medical Institute, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Department of Neurological Surgery, the Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Srinivasa N. Raja
- Department of Anesthesiology and Critical Care Medicine, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| |
Collapse
|
13
|
Chronic activation of Mas-related gene receptors (Mrg) reduces the potency of morphine-induced analgesia via PKC pathway in naive rats. Brain Res 2019; 1722:146363. [PMID: 31394092 DOI: 10.1016/j.brainres.2019.146363] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2018] [Revised: 07/09/2019] [Accepted: 08/03/2019] [Indexed: 01/27/2023]
Abstract
Mas oncogene-related gene receptors (Mrg) are uniquely distributed in small and medium cells of trigeminal and dorsal root ganglia (DRG). The physiological and pharmacological properties of Mrg are unknown. We have shown that intermittent activation of MrgC prevents and reverses morphine tolerance. Now we observed that intrathecal (i.t.) administration of the MrgC agonist bovine adrenal medulla 8-22 (BAM8-22, 3 nmol) for 3 and 6 days reduced the potency of morphine analgesia by 1.5 and 3.5 folds, respectively. Daily administration of BAM8-22 for 6 days also significantly decreased the tail flick latency. The administration of another MrgC agonist (Tyr6)-γ2-MSH-6-12 (MSH, 3 nmol) reduced morphine potency and the reduction was abolished following the co-administration of the protein kinase C (PKC) inhibitor chelerythrine chloride (CLT, 3 nmol). The chronic treatment with BAM8-22 or MSH increased the expression of PKC-gamma (PKCγ) in the cell membrane of spinal dorsal horn neurons and PKC-epsilon (PKCε) in the cell membrane and cytosol of DRG neurons. Moreover, the BAM8-22 treatment induced an increase in the expression of calcitonin gene-related peptide (CGRP) and neuronal nitric oxide synthase (nNOS) in small and medium cells in DRG. All of these responses were not seen when BAM8-22 or MSH was co-administered with the PKC inhibitor CLT (3 nmol) or GF-109203X (10 nmol). The present study suggested that the chronic activation of MrgC upregulated expressions of pronociceptive mediators via PKC signaling pathway leading to the suppression of antinociceptive property of morphine. These effects are opposite to those occurred when MrgC is activated acutely or moderately.
Collapse
|
14
|
The Ubiquitination of Spinal MrgC Alleviates Bone Cancer Pain and Reduces Intracellular Calcium Concentration in Spinal Neurons in Mice. Neurochem Res 2019; 44:2527-2535. [PMID: 31515677 DOI: 10.1007/s11064-019-02869-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 08/30/2019] [Accepted: 09/05/2019] [Indexed: 01/12/2023]
Abstract
Mas-related G-protein-coupled receptor subtype C (MrgC) has been shown to play an important role in the development of bone cancer pain. Ubiquitination is reported to participate in pain. However, whether MrgC ubiquitination plays a role in bone cancer pain remains unclear. To answer this question, we designed and performed this study. Osteosarcoma cells were implanted into the intramedullary space of the right femurs of C3H/HeJ mice to induce progressive bone cancer pain. MrgC agonist bovine adrenal medulla 8-22 (BAM 8-22) or MrgC antagonist anti-MrgC antibody were injected intrathecally on day 14 after bone cancer pain was successfully induced. The pain behaviors, the MrgC ubiquitination levels and intracellular calcium concentration in spinal neurons were measured before and after injection, respectively. With comparison to normal and sham group, mice in tumor group exhibited serious bone cancer pain on day 14, and the level of MrgC ubiquitination and intracellular calcium concentration in spinal neurons was significantly higher. Intrathecal injection of BAM 8-22 significantly alleviated bone cancer pain, increased the MrgC ubiquitination level and decreased intracellular calcium concentration in spinal neurons; however, these effects were reversed by administration of anti-MrgC antibody. Our study reveals that MrgC ubiquitination participates in the production and maintenance of bone cancer pain in mice, possibly through the regulation of intracellular calcium concentration in mice spinal neurons.
Collapse
|
15
|
Prchalová E, Hin N, Thomas AG, Veeravalli V, Ng J, Alt J, Rais R, Rojas C, Li Z, Hihara H, Aoki M, Yoshizawa K, Nishioka T, Suzuki S, Kopajtic T, Chatrath S, Liu Q, Dong X, Slusher BS, Tsukamoto T. Discovery of Benzamidine- and 1-Aminoisoquinoline-Based Human MAS-Related G-Protein-Coupled Receptor X1 (MRGPRX1) Agonists. J Med Chem 2019; 62:8631-8641. [PMID: 31498617 PMCID: PMC10079166 DOI: 10.1021/acs.jmedchem.9b01003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mas-related G-protein-coupled receptor X1 (MRGPRX1) is a human sensory neuron-specific receptor and has been actively investigated as a therapeutic target for the treatment of pain. By use of two HTS screening hit compounds, 4-(4-(benzyloxy)-3-methoxybenzylamino)benzimidamide (5a) and 4-(2-(butylsulfonamido)-4-methylphenoxy)benzimidamide (11a), as molecular templates, a series of human MRGPRX1 agonists were synthesized and evaluated for their agonist activity using HEK293 cells stably transfected with human MrgprX1. Conversion of the benzamidine moiety into a 1-aminoisoquinoline moiety carried out in the later stage of structural optimization led to the discovery of a highly potent MRGPRX1 agonist, N-(2-(1-aminoisoquinolin-6-yloxy)-4-methylphenyl)-2-methoxybenzenesulfonamide (16), not only devoid of positively charged amidinium group but also with superior selectivity over opioid receptors. In mice, compound 16 displayed favorable distribution to the spinal cord, the presumed site of action for the MRGPRX1-mediated analgesic effects.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - Hiroe Hihara
- Tsukuba Research Laboratories , Eisai Co., Ltd. , Tsukuba , Ibaraki 300-2635 , Japan
| | - Mika Aoki
- Tsukuba Research Laboratories , Eisai Co., Ltd. , Tsukuba , Ibaraki 300-2635 , Japan
| | - Kyoko Yoshizawa
- Tsukuba Research Laboratories , Eisai Co., Ltd. , Tsukuba , Ibaraki 300-2635 , Japan
| | - Tomoki Nishioka
- Tsukuba Research Laboratories , Eisai Co., Ltd. , Tsukuba , Ibaraki 300-2635 , Japan
| | - Shuichi Suzuki
- Tsukuba Research Laboratories , Eisai Co., Ltd. , Tsukuba , Ibaraki 300-2635 , Japan
| | - Theresa Kopajtic
- Biobehavioral Imaging and Molecular Neuropsychopharmacology Unit , National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health , Baltimore , Maryland 21224 , United States
| | - Sheena Chatrath
- Department of Anesthesiology and Center for the Study of Itch , Washington University School of Medicine , St. Louis , Missouri 63110 , United States
| | - Qin Liu
- Department of Anesthesiology and Center for the Study of Itch , Washington University School of Medicine , St. Louis , Missouri 63110 , United States
| | | | | | | |
Collapse
|
16
|
Zhang Y, Wang M, Lu Q, Li Q, Lin M, Huang J, Hong Y. Inhibitory Effects of Mas-Related Gene C Receptor on Chronic Morphine-Induced Spinal Glial Activation in Rats. J Pharmacol Exp Ther 2018; 368:237-245. [DOI: 10.1124/jpet.118.252494] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Accepted: 11/20/2018] [Indexed: 12/20/2022] Open
|
17
|
He SQ, Xu Q, Tiwari V, Yang F, Anderson M, Chen Z, Grenald SA, Raja SN, Dong X, Guan Y. Oligomerization of MrgC11 and μ-opioid receptors in sensory neurons enhances morphine analgesia. Sci Signal 2018; 11:eaao3134. [PMID: 29921657 PMCID: PMC6328051 DOI: 10.1126/scisignal.aao3134] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The μ-opioid receptor (MOR) agonist morphine is commonly used for pain management, but it has severe adverse effects and produces analgesic tolerance. Thus, alternative ways of stimulating MOR activity are needed. We found that MrgC11, a sensory neuron-specific G protein-coupled receptor, may form heteromeric complexes with MOR. Peptide-mediated activation of MrgC11 enhanced MOR recycling by inducing coendocytosis and sorting of MOR for membrane reinsertion. MrgC11 activation also inhibited the coupling of MOR to β-arrestin-2 and enhanced the morphine-dependent inhibition of cAMP production. Intrathecal coadministration of a low dose of an MrgC agonist potentiated acute morphine analgesia and reduced chronic morphine tolerance in wild-type mice but not in Mrg-cluster knockout (Mrg KO) mice. BAM22, a bivalent agonist of MrgC and opioid receptors, enhanced the interaction between MrgC11 and MOR and produced stronger analgesia than did the individual monovalent agonists. Morphine-induced neuronal and pain inhibition was reduced in Mrg KO mice compared to that in wild-type mice. Our results uncover MrgC11-MOR interactions that lead to positive functional modulation of MOR. MrgC shares genetic homogeneity and functional similarity with human MrgX1. Thus, harnessing this positive modulation of MOR function by Mrg signaling may enhance morphine analgesia in a sensory neuron-specific fashion to limit central side effects.
Collapse
Affiliation(s)
- Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Qian Xu
- Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Vinod Tiwari
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael Anderson
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zhiyong Chen
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Shaness A Grenald
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Srinivasa N Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xinzhong Dong
- Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| |
Collapse
|
18
|
Tiwari V, Anderson M, Yang F, Tiwari V, Pharm M, Zheng Q, He SQ, Zhang T, Shu B, Chen X, Grenald SA, Stephens KE, Chen Z, Dong X, Raja SN, Guan Y. Peripherally Acting μ-Opioid Receptor Agonists Attenuate Ongoing Pain-associated Behavior and Spontaneous Neuronal Activity after Nerve Injury in Rats. Anesthesiology 2018; 128:1220-1236. [PMID: 29601322 PMCID: PMC5953805 DOI: 10.1097/aln.0000000000002191] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
BACKGROUND Ongoing neuropathic pain is difficult to treat. The authors examined whether dermorphin [D-Arg2, Lys4] (1-4) amide, a peripherally acting µ-opioid receptor agonist, attenuates ongoing pain-associated manifestations after nerve injury in rats and mice. METHODS Using conditioned place preference assay, the authors tested whether animals show a preference to the environment associated with drug treatment. Wide-dynamic range and dorsal root ganglion neuronal activities were measured by electrophysiology recording and calcium imaging. RESULTS Nerve-injured animals stayed longer in dermorphin [D-Arg2, Lys4] (1-4) amide-paired chamber after conditioning than during preconditioning (rats: 402.4 ± 61.3 vs. 322.1 ± 45.0 s, 10 mg/kg, n = 9, P = 0.009; mice: 437.8 ± 59.4 vs. 351.3 ± 95.9 s, 2 mg/kg, n = 8, P = 0.047). Topical ganglionic application of dermorphin [D-Arg2, Lys4] (1-4) amide (5 μM, 1 μl, n = 5) reduced the numbers of small-diameter dorsal root ganglion neurons that showed spontaneous activity (1.1 ± 0.4 vs. 1.5 ± 0.3, P = 0.044) and that were activated by test stimulation (15.5 ± 5.5 vs. 28.2 ± 8.2, P = 0.009) after injury. In neuropathic rats, dermorphin [D-Arg2, Lys4] (1-4) amide (10 mg/kg, n = 8) decreased spontaneous firing rates in wide-dynamic range neurons to 53.2 ± 46.6% of predrug level, and methylnaltrexone (5 mg/kg, n = 9) blocked dermorphin [D-Arg2, Lys4] (1-4) amide-induced place preference and inhibition of wide-dynamic range neurons. Dermorphin [D-Arg2, Lys4] (1-4) amide increased paw withdrawal threshold (17.5 ± 2.2 g) from baseline (3.5 ± 0.7 g, 10 mg/kg, n = 8, P = 0.002) in nerve-injured rats, but the effect diminished after repeated administrations. CONCLUSIONS Peripherally acting μ-opioids may attenuate ongoing pain-related behavior and its neurophysiologic correlates. Yet, repeated administrations cause antiallodynic tolerance.
Collapse
Affiliation(s)
- Vinod Tiwari
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad, Gandhinagar, 382355, Gujarat, India
| | - Michael Anderson
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | | | - M. Pharm
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Qin Zheng
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Tong Zhang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Department of Neurology, Tiantan Hospital, Capital Medical University, Beijing, 100050, China
| | - Bin Shu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Wuhan, 430030, China
| | - Xueming Chen
- Department of Orthopedics, Luhe Hospital, Capital Medical University, Beijing, 100020, China
| | - Shaness A. Grenald
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Kimberly E. Stephens
- Department of Pharmacology and Molecular Sciences, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Center for Epigenetics, the Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Zhiyong Chen
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
- Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Srinivasa N. Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205, USA
| |
Collapse
|
19
|
Involvement of MrgprC in Electroacupuncture Analgesia for Attenuating CFA-Induced Thermal Hyperalgesia by Suppressing the TRPV1 Pathway. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2018; 2018:9102107. [PMID: 29619074 PMCID: PMC5829339 DOI: 10.1155/2018/9102107] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Revised: 12/22/2017] [Accepted: 01/04/2018] [Indexed: 01/20/2023]
Abstract
Mas-related G-protein-coupled receptor C (MrgprC) plays an important role in modulating chronic inflammatory pain. Electroacupuncture (EA) has a satisfactory analgesic effect on chronic pain. This study aimed to investigate the involvement of MrgprC and its transient receptor potential vanilloid 1 (TRPV1) pathway in EA analgesia in chronic inflammatory pain. Chronic inflammatory pain was induced by subcutaneously injecting complete Freund's adjuvant (CFA) into the left hind paw. EA (2/100 Hz) stimulation was administered. MrgprC siRNAs were intrathecally administered to inhibit MrgprC expression, and bovine adrenal medulla 8-22 (BAM8-22) was used to activate MrgprC. The mechanical allodynia was decreased by EA significantly since day 3. The piled analgesic effect of EA was partially blocked by 6 intrathecal administrations of MrgprC siRNA. Both EA and BAM8-22 could downregulate the expression of TRPV1 and PKC in both the DRG and the SCDH. Both EA and BAM8-22 could also decrease the TRPV1 translocation and p-TRPV1 level in both the DRG and the SCDH. The effects of EA on PKCε, TRPV1 translocation, and p-TRPV1 in both the DRG and the SCDH were reversed by MrgprC siRNA. The results indicated that MrgprC played crucial roles in chronic pain modulation and was involved in EA analgesia partially through the regulation of TRPV1 function at the DRG and SCDH levels.
Collapse
|
20
|
Fernandes V, Sharma D, Vaidya S, P A S, Guan Y, Kalia K, Tiwari V. Cellular and molecular mechanisms driving neuropathic pain: recent advancements and challenges. Expert Opin Ther Targets 2018; 22:131-142. [PMID: 29285962 DOI: 10.1080/14728222.2018.1420781] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
INTRODUCTION Current pharmacotherapeutics for neuropathic pain offer only symptomatic relief without treating the underlying pathophysiology. Additionally, they are associated with various dose-limiting side effects. Pain research in the past few decades has revolved around the role of oxidative-nitrosative stress, protein kinases, glial cell activation, and inflammatory signaling cascades but has failed to produce specific and effective therapies. Areas covered: This review focuses on recent advances in cellular and molecular mechanisms of neuropathic pain that may be translated into future therapies. We discuss emerging targets such as WNT signaling mechanisms, the tetrahydrobiopterin pathway, Mrg receptors, endogenous lipid mediators, micro-RNAs and their roles in pain regulation. Recent evidence is also presented regarding genetic and epigenetic mechanisms of pain modulation. Expert opinion: During chronic neuropathic pain, maladaptation occurs in the peripheral and central nervous systems, including a shift in microglial phenotype from a surveillance state to an activated state. Microglial activation leads to an altered expression of cell surface proteins, growth factors, and intracellular signaling molecules that contribute to development of a neuroinflammatory cascade and chronic pain sensitization. Specific targeting of these cellular and molecular mechanisms may provide the key to development of effective neuropathic pain therapies that have minimal side effects.
Collapse
Affiliation(s)
- Valencia Fernandes
- a Department of Pharmacology and Toxicology , National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad , Gandhinagar , India
| | - Dilip Sharma
- a Department of Pharmacology and Toxicology , National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad , Gandhinagar , India
| | - Shivani Vaidya
- a Department of Pharmacology and Toxicology , National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad , Gandhinagar , India
| | - Shantanu P A
- a Department of Pharmacology and Toxicology , National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad , Gandhinagar , India
| | - Yun Guan
- b Department of Anesthesiology and Critical Care Medicine , Johns Hopkins University School of Medicine , Baltimore , MD , USA
| | - Kiran Kalia
- a Department of Pharmacology and Toxicology , National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad , Gandhinagar , India
| | - Vinod Tiwari
- a Department of Pharmacology and Toxicology , National Institute of Pharmaceutical Education and Research (NIPER)-Ahmedabad , Gandhinagar , India.,b Department of Anesthesiology and Critical Care Medicine , Johns Hopkins University School of Medicine , Baltimore , MD , USA
| |
Collapse
|
21
|
Activation of cannabinoid CB1 receptor contributes to suppression of spinal nociceptive transmission and inhibition of mechanical hypersensitivity by Aβ-fiber stimulation. Pain 2017; 157:2582-2593. [PMID: 27589093 DOI: 10.1097/j.pain.0000000000000680] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Activation of Aβ-fibers is an intrinsic feature of spinal cord stimulation (SCS) pain therapy. Cannabinoid receptor type 1 (CB1) is important to neuronal plasticity and pain modulation, but its role in SCS-induced pain inhibition remains unclear. In this study, we showed that CB1 receptors are expressed in both excitatory and inhibitory interneurons in substantia gelatinosa (SG). Patch-clamp recording of the evoked excitatory postsynaptic currents (eEPSCs) in mice after spinal nerve ligation (SNL) showed that electrical stimulation of Aβ-fibers (Aβ-ES) using clinical SCS-like parameters (50 Hz, 0.2 millisecond, 10 μA) induced prolonged depression of eEPSCs to C-fiber inputs in SG neurons. Pretreatment with CB1 receptor antagonist AM251 (2 μM) reduced the inhibition of C-eEPSCs by Aβ-ES in both excitatory and inhibitory SG neurons. We further determined the net effect of Aβ-ES on spinal nociceptive transmission in vivo by recording spinal local field potential in SNL rats. Epidural SCS (50 Hz, Aβ-plateau, 5 minutes) attenuated C-fiber-evoked local field potential. This effect of SCS was partially reduced by spinal topical application of AM251 (25 μg, 50 μL), but not CB2 receptor antagonist AM630 (100 μg). Finally, intrathecal pretreatment with AM251 (50 μg, 15 μL) in SNL rats blocked the inhibition of behavioral mechanical hypersensitivity by SCS (50 Hz, 0.2 millisecond; 80% of motor threshold, 60 minutes). Our findings suggest that activation of spinal CB1 receptors may contribute to synaptic depression to high-threshold afferent inputs in SG neurons after Aβ-ES and may be involved in SCS-induced inhibition of spinal nociceptive transmission after nerve injury.
Collapse
|
22
|
Zhang Y, Wang K, Lin M, Li Q, Hong Y. Inhibition of morphine tolerance by MrgC receptor via modulation of interleukin-1β and matrix metalloproteinase 9 in dorsal root ganglia in rats. Eur J Pharmacol 2017; 815:10-17. [PMID: 28993160 DOI: 10.1016/j.ejphar.2017.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Revised: 09/30/2017] [Accepted: 10/05/2017] [Indexed: 11/27/2022]
Abstract
Opiate tolerance is a critical issue in pain management. Previous studies show that activation of Mas-related gene (Mrg) C receptor can modulate the development of morphine tolerance. This study was designed to investigate the underlying mechanism(s). Intrathecal (i.t.) administration of morphine (20µg) increased the expression of interleukin-1β (IL-1β) and matrix metalloproteinase-9 (MMP-9) in small- and medium-sized neurons in dorsal root ganglia (DRG). Co-administration of bovine adrenal medulla 8-22 (BAM8-22), a selective MrgC receptor agonist, via i.t. route inhibited the increase of IL-1β and MMP-9 in the DRG. Exposure of DRG cultures to morphine (3.3μM) for 3 or 5 days, but not for 1 day, induced an increase in MMP-9 mRNA expression. The treatment with BAM8-22 (10nM) for 20, 40 or 60min abolished chronic (5 days) morphine-induced increase of MMP-9 mRNA in the cultured DRG. The treatment with BAM8-22 for 1h inhibited chronic morphine-induced increase of MMP-9 and IL-1β mRNA in DRG but these effects were abolished by MrgC receptor antibody. The treatment with BAM8-22 for 24 and 72h respectively inhibited and enhanced morphine-induced expression of MMP-9 and IL-1β mRNA in the cultured DRG. The BAM8-22-induced inhibition and enhancement were abolished by MrgC receptor antibody. The results suggest that the inhibition of IL-1β and MMP-9 expressions in DRG underlain the modulation of morphine tolerance by the acute activation of MrgC receptors. The chronic activation of MrgC receptors can facilitate morphine-induced increase of MMP-9 and IL-1β expressions in DRG.
Collapse
Affiliation(s)
- Yue Zhang
- Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian 350117, China
| | - Kai Wang
- Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian 350117, China
| | - Minyan Lin
- Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian 350117, China
| | - Qi Li
- Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian 350117, China
| | - Yanguo Hong
- Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University, Fuzhou, Fujian 350117, China.
| |
Collapse
|
23
|
Targeting human Mas-related G protein-coupled receptor X1 to inhibit persistent pain. Proc Natl Acad Sci U S A 2017; 114:E1996-E2005. [PMID: 28223516 DOI: 10.1073/pnas.1615255114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Human Mas-related G protein-coupled receptor X1 (MRGPRX1) is a promising target for pain inhibition, mainly because of its restricted expression in nociceptors within the peripheral nervous system. However, constrained by species differences across Mrgprs, drug candidates that activate MRGPRX1 do not activate rodent receptors, leaving no responsive animal model to test the effect on pain in vivo. Here, we generated a transgenic mouse line in which we replaced mouse Mrgprs with human MrgprX1 This humanized mouse allowed us to characterize an agonist [bovine adrenal medulla 8-22 (BAM8-22)] and a positive allosteric modulator (PAM), ML382, of MRGPRX1. Cellular studies suggested that ML382 enhances the ability of BAM8-22 to inhibit high-voltage-activated Ca2+ channels and attenuate spinal nociceptive transmission. Importantly, both BAM8-22 and ML382 effectively attenuated evoked, persistent, and spontaneous pain without causing obvious side effects. Notably, ML382 by itself attenuated both evoked pain hypersensitivity and spontaneous pain in MrgprX1 mice after nerve injury without acquiring coadministration of an exogenous agonist. Our findings suggest that humanized MrgprX1 mice provide a promising preclinical model and that activating MRGPRX1 is an effective way to treat persistent pain.
Collapse
|
24
|
Reversal of neurochemical alterations in the spinal dorsal horn and dorsal root ganglia by Mas-related gene (Mrg) receptors in a rat model of spinal nerve injury. Neurobiol Dis 2016; 91:274-83. [DOI: 10.1016/j.nbd.2016.03.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 03/12/2016] [Accepted: 03/21/2016] [Indexed: 12/17/2022] Open
|
25
|
Activation of Peripheral μ-opioid Receptors by Dermorphin [D-Arg2, Lys4] (1-4) Amide Leads to Modality-preferred Inhibition of Neuropathic Pain. Anesthesiology 2016; 124:706-20. [PMID: 26756519 DOI: 10.1097/aln.0000000000000993] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Opioids have long been regarded as the most effective drugs for the treatment of severe acute and chronic pain. Unfortunately, their therapeutic efficacy and clinical utility have been limited because of central and peripheral side effects. METHODS To determine the therapeutic value of peripheral μ-opioid receptors as a target for neuropathic pain treatment, the authors examined the effects of dermorphin [D-Arg2, Lys4] (1-4) amide (DALDA), a hydrophilic, peripherally acting μ-opioid receptor agonist, in male and female rats with spinal nerve ligation-induced neuropathic pain. The authors also utilized behavioral, pharmacologic, electrophysiologic, and molecular biologic tools to characterize DALDA's possible mechanisms of action in male rats. RESULTS DALDA, administered subcutaneously, had 70 times greater efficacy for inhibiting thermal (n = 8 to 11/group) than mechanical hypersensitivity (n = 6 to 8/group) in male rats. The pain inhibitory effects of DALDA on mechanical and heat hypersensitivity were abolished in animals pretreated with systemic methylnaltrexone (n = 7 to 9/group), a peripheral μ-opioid receptor antagonist. In the spinal wide-dynamic range neurons, systemic DALDA inhibited C-fiber-mediated, but not A-fiber-mediated, response in neuropathic male rats (n = 13). In primary sensory neurons, DALDA inhibited the capsaicin-induced [Ca2+] increase more than the β-alanine-induced [Ca] increase (n = 300); capsaicin and β-alanine activate subpopulations of neurons involved in the signaling of heat and mechanical pain, respectively. DALDA-treated rats (n = 5 to 8/group) did not exhibit motor deficits and locomotor impairment suggesting that it does not induce central side effects. CONCLUSIONS These findings suggest that DALDA may represent a potential alternative to current opioid therapy for the treatment of neuropathic pain and is likely to be associated with minimal adverse effects.
Collapse
|
26
|
Wang D, Xue Y, Chen Y, Ruan L, Hong Y. Mas-related gene (Mrg) C receptors inhibit mechanical allodynia and spinal microglia activation in the early phase of neuropathic pain in rats. Neurosci Lett 2016; 618:115-121. [PMID: 26952974 DOI: 10.1016/j.neulet.2016.03.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 03/01/2016] [Accepted: 03/02/2016] [Indexed: 02/06/2023]
Abstract
Mas-related gene (Mrg) C receptors are exclusively expressed in the trigeminal and dorsal root ganglia (DRG). However, their functional roles are poorly understood. This study was aimed to determine the effect of MrgC receptors on pain hypersensitivity in the early phase of neuropathic pain and its underlying mechanisms. Intrathecal (i.t.) administration of the selective MrgC receptor agonist bovine adrenal medulla 8-22 (BAM8-22) at 1 or 10nmol attenuated mechanical allodynia one day after L5 spinal nerve ligation (SNL) surgery. I.t. BAM8-22 (10 nmol) inhibited SNL-induced microglia activation in the spinal dorsal horn on day 2 post-SNL. The BAM8-22 treatment also abolished SNL-induced upregulation of neuronal nitric oxide synthesis (nNOS) in the dorsal root ganglia (DRG). On the other hand, SNL, but not sham, surgery reduced the expression of MrgC receptor mRNA in the injured L5 DRG without changing thier levels in the adjacent uninjured L4 or L6 DRG on day 2 following the surgery. These results suggest that the activation of MrgC receptors can relieve pain hypersensitivity by the inhibition of nNOS increase in DRG neurons and microglia activation in the spinal dorsal horn in the early time following peripheral nerve injury. This study provides evidence that MrgC receptors could be targeted as a novel therapy for neuropathic pain with limited unwanted effects.
Collapse
Affiliation(s)
- Dongmei Wang
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China
| | - Yaping Xue
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China
| | - Yajuan Chen
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China
| | - Liqin Ruan
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China
| | - Yanguo Hong
- College of Life Sciences and Provincial Key Laboratory of Developmental Biology and Neuroscience, Fujian Normal University Fuzhou, Fujian 350108, People's Republic of China.
| |
Collapse
|
27
|
Sun Y, Zhang J, Lei Y, Lu C, Hou B, Ma Z, Gu X. Activation of spinal MrgC-Gi-NR2B-nNOS signaling pathway by Mas oncogene-related gene C receptor agonist bovine adrenal medulla 8-22 attenuates bone cancer pain in mice. Am J Transl Res 2016; 8:1144-1154. [PMID: 27158400 PMCID: PMC4846957] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 01/18/2016] [Indexed: 06/05/2023]
Abstract
OBJECTIVES In the present study, we investigate the effects of Mas oncogene-related gene (Mrg) C receptors (MrgC) on the expression and activation of spinal Gi protein, N-methyl-D-aspartate receptor subunit 2B (NR2B), and neuronal nitric oxide synthase (nNOS) in mouse model of bone cancer pain. METHODS The number of spontaneous foot lift (NSF) and paw withdrawal mechanical threshold (PWMT) were measured after inoculation of tumor cells and intrathecal injection of MrgC agonist bovine adrenal medulla 8-22 (BAM8-22) or MrgC antagonist anti-MrgC for 14 days after operation. Expression of spinal MrgC, Gi protein, NR2B and nNOS and their phosphorylated forms after inoculation was examined by immunohistochemistry and Western blotting. Double labeling was used to identify the co-localization of NR2B or nNOS with MrgC in spinal cord dorsal horn (SCDH) neurons. The effects of intrathecal injection of BAM8-22 or anti-MrgC on nociceptive behaviors and the corresponding expression of spinal MrgC, Gi protein, NR2B and nNOS were also investigated. RESULTS The expression of spinal MrgC, Gi protein, NR2B, and nNOS was higher in tumor-bearing mice in comparison to sham mice or normal mice. Intrathecal injection of MrgC agonist BAM8-22 significantly alleviated bone cancer pain, up-regulated MrgC and Gi protein expression, and down-regulated the expression of spinal p-NR2B, t-nNOS and p-nNOS in SCDH on day 14 after operation, whereas administration of anti-MrgC produced the opposite effect. Meanwhile, MrgC-like immunoreactivity (IR) co-localizes with NR2B-IR or nNOS-IR in SCDH neurons. CONCLUSIONS The present study demonstrates that MrgC-activated spinal Gi-NR2B-nNOS signaling pathway plays important roles in the development of bone cancer pain. These findings may provide a novel strategy for the treatment of bone cancer pain.
Collapse
Affiliation(s)
- Yu'e Sun
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, P. R. China
| | - Juan Zhang
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, P. R. China
| | - Yishan Lei
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, P. R. China
| | - Cui'e Lu
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, P. R. China
| | - Bailing Hou
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, P. R. China
| | - Zhengliang Ma
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, P. R. China
| | - Xiaoping Gu
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, P. R. China
| |
Collapse
|
28
|
Schröder W, Alique M, Herrero J. Effects of the mas-related gene (Mrg) C receptor agonist BAM6-22 on nociceptive reflex activity in naive, monoarthritic and mononeuropathic rats after intraplantar and intrathecal administration. Eur J Pharmacol 2016; 770:147-53. [DOI: 10.1016/j.ejphar.2015.11.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 11/19/2015] [Accepted: 11/20/2015] [Indexed: 11/25/2022]
|
29
|
Tiwari V, Tiwari V, He S, Zhang T, Raja SN, Dong X, Guan Y. Mas-Related G Protein-Coupled Receptors Offer Potential New Targets for Pain Therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 904:87-103. [PMID: 26900065 DOI: 10.1007/978-94-017-7537-3_7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The founding member of the Mas-related G-protein-coupled receptor (Mrgpr) family was discovered in 1986. Since then, many more members of this receptor family have been identified in multiple species, and their physiologic functions have been investigated widely. Because they are expressed exclusively in small-diameter primary sensory neurons, the roles of Mrgpr proteins in pain and itch have been best studied. This review will focus specifically on the current knowledge of their roles in pathological pain and the potential development of new pharmacotherapies targeted at some Mrgprs for the treatment of chronic pain. We will also discuss the limitations and future scope of this receptor family in pain treatment.
Collapse
Affiliation(s)
- Vineeta Tiwari
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Vinod Tiwari
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Shaoqiu He
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Tong Zhang
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Srinivasa N Raja
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Xinzhong Dong
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Yun Guan
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
| |
Collapse
|
30
|
Sun YE, Lu CE, Lei Y, Liu Y, Ma Z, Gu X. Mas-related G-protein-coupled receptor c agonist bovine adrenal medulla 8-22 attenuates bone cancer pain in mice. Int J Clin Exp Med 2015; 8:20178-20187. [PMID: 26884930 PMCID: PMC4723775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/21/2015] [Indexed: 06/05/2023]
Abstract
OBJECTIVES The aim of this study is to investigate the effects of Mas-related G-protein-coupled receptor C (MrgC) agonist bovine adrenal medulla 8-22 (BAM8-22) on bone cancer pain and mirror-image pain. METHODS Bone cancer pain was induced by intramedullary injection of NC2472 fibrosarcoma cells in the mice. BAM8-22 and/or anti-MrgC antibody were injected intrathecally at day 14 after bone cancer induction and their effects on pain behaviors were detected. The pain behaviours were assessed by the number of spontaneous foot lifts and paw withdrawal mechanical threshold (PWMT) tests. MrgC expression was detected using western blot analysis and immunofluorescence assay. RESULTS There were increased bone cancer pain and mirror-image pain in the tumor-bearing mice while not in the sham-treated mice. BAM8-22 attenuated bone cancer pain in mice dose dependently with the highest effects at 2 hr after BAM8-22 administration, and anti-MrgC antibody reversed the effects of BAM8-22. However, intrathecal administration of BAM8-22 did not affect the mirror-image pain. Furthermore, BAM8-22 stimulated the expression of MrgC in the spinal dorsal horn. CONCLUSIONS MrgC agonist BAM8-22 could attenuate bone cancer pain in mice. This study may provide a novel strategy for the treatment of bone cancer pain.
Collapse
Affiliation(s)
- Yu-E Sun
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, Jiangsu Province, China
| | - Cui-E Lu
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, Jiangsu Province, China
| | - Yishan Lei
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, Jiangsu Province, China
| | - Yue Liu
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, Jiangsu Province, China
| | - Zhengliang Ma
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, Jiangsu Province, China
| | - Xiaoping Gu
- Department of Anaesthesiology, Affiliated Drum-Tower Hospital of Medical College of Nanjing University Nanjing 210008, Jiangsu Province, China
| |
Collapse
|
31
|
Bader M, Alenina N, Andrade-Navarro MA, Santos RA. MAS and its related G protein-coupled receptors, Mrgprs. Pharmacol Rev 2015; 66:1080-105. [PMID: 25244929 DOI: 10.1124/pr.113.008136] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The Mas-related G protein-coupled receptors (Mrgprs or Mas-related genes) comprise a subfamily of receptors named after the first discovered member, Mas. For most Mrgprs, pruriception seems to be the major function based on the following observations: 1) they are relatively promiscuous in their ligand specificity with best affinities for itch-inducing substances; 2) they are expressed in sensory neurons and mast cells in the skin, the main cellular components of pruriception; and 3) they appear in evolution first in tetrapods, which have arms and legs necessary for scratching to remove parasites or other noxious substances from the skin before they create harm. Because parasites coevolved with hosts, each species faced different parasitic challenges, which may explain another striking observation, the multiple independent duplication and expansion events of Mrgpr genes in different species as a consequence of parallel adaptive evolution. Their predominant expression in dorsal root ganglia anticipates additional functions of Mrgprs in nociception. Some Mrgprs have endogenous ligands, such as β-alanine, alamandine, adenine, RF-amide peptides, or salusin-β. However, because the functions of these agonists are still elusive, the physiologic role of the respective Mrgprs needs to be clarified. The best studied Mrgpr is Mas itself. It was shown to be a receptor for angiotensin-1-7 and to exert mainly protective actions in cardiovascular and metabolic diseases. This review summarizes the current knowledge about Mrgprs, their evolution, their ligands, their possible physiologic functions, and their therapeutic potential.
Collapse
Affiliation(s)
- Michael Bader
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Natalia Alenina
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Miguel A Andrade-Navarro
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| | - Robson A Santos
- Max-Delbrück-Center for Molecular Medicine, Berlin, Germany (M.B., N.A., M.A.A.-N.); Charité-University Medicine, Berlin, Germany (M.B.); Institute for Biology, University of Lübeck, Lübeck, Germany (M.B.); and Department of Physiology and Biophysics, Federal University of Minas Gerais, Belo Horizonte, Brazil (M.B., N.A., R.A.S.)
| |
Collapse
|
32
|
Wang D, Wang P, Jiang J, Lv Q, Zeng X, Hong Y. Activation of Mas Oncogene-Related G Protein–Coupled Receptors Inhibits Neurochemical Alterations in the Spinal Dorsal Horn and Dorsal Root Ganglia Associated with Inflammatory Pain in Rats. J Pharmacol Exp Ther 2015; 354:431-439. [DOI: 10.1124/jpet.115.225672] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023] Open
|
33
|
Sdrulla AD, Xu Q, He SQ, Tiwari V, Yang F, Zhang C, Shu B, Shechter R, Raja SN, Wang Y, Dong X, Guan Y. Electrical stimulation of low-threshold afferent fibers induces a prolonged synaptic depression in lamina II dorsal horn neurons to high-threshold afferent inputs in mice. Pain 2015; 156:1008-1017. [PMID: 25974163 PMCID: PMC4437220 DOI: 10.1097/01.j.pain.0000460353.15460.a3] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Electrical stimulation of low-threshold Aβ-fibers (Aβ-ES) is used clinically to treat neuropathic pain conditions that are refractory to pharmacotherapy. However, it is unclear how Aβ-ES modulates synaptic responses to high-threshold afferent inputs (C-, Aδ-fibers) in superficial dorsal horn. Substantia gelatinosa (SG) (lamina II) neurons are important for relaying and modulating converging spinal nociceptive inputs. We recorded C-fiber-evoked excitatory postsynaptic currents (eEPSCs) in spinal cord slices in response to paired-pulse test stimulation (500 μA, 0.1 millisecond, 400 milliseconds apart). We showed that 50-Hz and 1000-Hz, but not 4-Hz, Aβ-ES (10 μA, 0.1 millisecond, 5 minutes) induced prolonged inhibition of C-fiber eEPSCs in SG neurons in naive mice. Furthermore, 50-Hz Aβ-ES inhibited both monosynaptic and polysynaptic forms of C-fiber eEPSC in naive mice and mice that had undergone spinal nerve ligation (SNL). The paired-pulse ratio (amplitude second eEPSC/first eEPSC) increased only in naive mice after 50-Hz Aβ-ES, suggesting that Aβ-ES may inhibit SG neurons by different mechanisms under naive and nerve-injured conditions. Finally, 50-Hz Aβ-ES inhibited both glutamatergic excitatory and GABAergic inhibitory interneurons, which were identified by fluorescence in vGlut2-Td and glutamic acid decarboxylase-green fluorescent protein transgenic mice after SNL. These findings show that activities in Aβ-fibers lead to frequency-dependent depression of synaptic transmission in SG neurons in response to peripheral noxious inputs. However, 50-Hz Aβ-ES failed to induce cell-type-selective inhibition in SG neurons. The physiologic implication of this novel form of synaptic depression for pain modulation by Aβ-ES warrants further investigation.
Collapse
Affiliation(s)
- Andrei D. Sdrulla
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Qian Xu
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
- Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Vinod Tiwari
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Chen Zhang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
| | - Bin Shu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Ronen Shechter
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Srinivasa N. Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Yun Wang
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
- Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| |
Collapse
|
34
|
Li Z, He SQ, Tseng PY, Xu Q, Tiwari V, Yang F, Shu B, Zhang T, Tang Z, Raja SN, Wang Y, Dong X, Guan Y. The inhibition of high-voltage-activated calcium current by activation of MrgC11 involves phospholipase C-dependent mechanisms. Neuroscience 2015; 300:393-403. [PMID: 26022362 DOI: 10.1016/j.neuroscience.2015.05.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 05/05/2015] [Accepted: 05/18/2015] [Indexed: 01/27/2023]
Abstract
High-voltage-activated (HVA) calcium channels play an important role in synaptic transmission. Activation of Mas-related G-protein-coupled receptor subtype C (MrgC; mouse MrgC11, rat homolog rMrgC) inhibits HVA calcium current (ICa) in small-diameter dorsal root ganglion (DRG) neurons, but the intracellular signaling cascade underlying MrgC agonist-induced inhibition of HVA ICa in native DRG neurons remains unclear. To address this question, we conducted patch-clamp recordings in MrgA3-eGFP-wild-type mice, in which most MrgA3-eGFP(+) DRG neurons co-express MrgC11 and can be identified for recording. We found that the inhibition of HVA ICa by JHU58 (0.001-100nM, a dipeptide, MrgC-selective agonist) was significantly reduced by pretreatment with a phospholipase C (PLC) inhibitor (U73122, 1μM), but not by its inactive analog (U73343) or vehicle. Further, in rats that had undergone spinal nerve injury, pretreatment with intrathecal U73122 nearly abolished the inhibition of mechanical hypersensitivity by intrathecal JHU58. The inhibition of HVA ICa in MrgA3-eGFP(+) neurons by JHU58 (100nM) was partially reduced by pretreatment with a Gβγ blocker (gallein, 100μM). However, applying a depolarizing prepulse and blocking the Gαi and Gαs pathways with pertussis toxin (PTX) (0.5μg/mL) and cholera toxin (CTX) (0.5μg/mL), respectively, had no effect. These findings suggest that activation of MrgC11 may inhibit HVA ICa in mouse DRG neurons through a voltage-independent mechanism that involves activation of the PLC, but not Gαi or Gαs, pathway.
Collapse
Affiliation(s)
- Z Li
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - S-Q He
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - P-Y Tseng
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Q Xu
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - V Tiwari
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - F Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - B Shu
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Wuhan 430030, China
| | - T Zhang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing 100050, China
| | - Z Tang
- Nanjing University of Chinese Medicine, 138 Xianlin Road, Nanjing, Jiangsu 210023, China
| | - S N Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA
| | - Y Wang
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020, China
| | - X Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA; Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, MD 21287, USA.
| | - Y Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD 21205, USA.
| |
Collapse
|
35
|
Hin N, Alt J, Zimmermann SC, Delahanty G, Ferraris DV, Rojas C, Li F, Liu Q, Dong X, Slusher BS, Tsukamoto T. Peptidomimetics of Arg-Phe-NH2 as small molecule agonists of Mas-related gene C (MrgC) receptors. Bioorg Med Chem 2014; 22:5831-7. [PMID: 25288495 DOI: 10.1016/j.bmc.2014.09.025] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 09/05/2014] [Accepted: 09/11/2014] [Indexed: 10/24/2022]
Abstract
A series of Arg-Phe-NH2 peptidomimetics containing an Arg mimetic were synthesized and tested as agonists of human MrgX1, rat MrgC, and mouse MrgC11 receptors. As predicted from the previously established species specificity, these peptidomimetics were found to be devoid of MrgX1 agonist activity. In contrast, these compounds acted as agonists of MrgC and/or MrgC11 with varying degrees of potency. These new peptidomimetics should complement the existing small molecule human MrgX1 agonists and enhance our ability to assess the therapeutic utility of targeting Mrg receptors in rodent models.
Collapse
Affiliation(s)
- Niyada Hin
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Jesse Alt
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Sarah C Zimmermann
- Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Greg Delahanty
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Dana V Ferraris
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Camilo Rojas
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Fengxian Li
- Center for the Study of Itch and Departments of Anesthesiology and Anatomy & Neurobiology, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Qin Liu
- Center for the Study of Itch and Departments of Anesthesiology and Anatomy & Neurobiology, Washington University School of Medicine, St Louis, MO 63110, United States
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Barbara S Slusher
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, United States; Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, United States
| | - Takashi Tsukamoto
- Brain Science Institute, Johns Hopkins University, Baltimore, MD 21205, United States; Department of Neurology, Johns Hopkins University, Baltimore, MD 21205, United States.
| |
Collapse
|
36
|
Wen W, Wang Y, Li Z, Tseng PY, McManus OB, Wu M, Li M, Lindsley CW, Dong X, Hopkins CR. Discovery and characterization of 2-(cyclopropanesulfonamido)-N-(2-ethoxyphenyl)benzamide, ML382: a potent and selective positive allosteric modulator of MrgX1. ChemMedChem 2014; 10:57-61. [PMID: 25209672 DOI: 10.1002/cmdc.201402277] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2014] [Indexed: 11/08/2022]
Abstract
Previous studies have shown that the activation of mouse MrgC11, a G-protein-coupled receptor, by its peptide ligand BAM8-22 can inhibit chronic pain. A large-scale screen has been carried out to isolate small-molecule allosteric agonists of MrgX1, the human homologue of MrgC11. The goal of this study is to improve the efficacy and potency of positive allosteric modulators (PAMs) with therapeutic implications in combating chronic pain. Herein we report an iterative parallel synthesis effort and a structure-activity relationship study of a series of arylsulfonamides which led to the discovery of the first PAM of MrgX1, ML382.
Collapse
Affiliation(s)
- Wandong Wen
- Department of Pharmacology, Vanderbilt Center for Neuroscience Drug Discovery, Vanderbilt Specialized Chemistry Center (MLPCN), Vanderbilt University Medical Center, Nashville, TN 37232-6600 (USA)
| | | | | | | | | | | | | | | | | | | |
Collapse
|
37
|
Li Z, He SQ, Xu Q, Yang F, Tiwari V, Liu Q, Tang Z, Han L, Chu YX, Wang Y, Hin N, Tsukamoto T, Slusher B, Guan X, Wei F, Raja SN, Dong X, Guan Y. Activation of MrgC receptor inhibits N-type calcium channels in small-diameter primary sensory neurons in mice. Pain 2014; 155:1613-1621. [PMID: 24813294 PMCID: PMC4104261 DOI: 10.1016/j.pain.2014.05.008] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 04/16/2014] [Accepted: 05/02/2014] [Indexed: 01/24/2023]
Abstract
Mas-related G-protein-coupled receptor subtype C (mouse MrgC11 and rat rMrgC), expressed specifically in small-diameter primary sensory neurons, may constitute a novel pain inhibitory mechanism. We have shown previously that intrathecal administration of MrgC-selective agonists can strongly attenuate persistent pain in various animal models. However, the underlying mechanisms for MrgC agonist-induced analgesia remain elusive. Here, we conducted patch-clamp recordings to test the effect of MrgC agonists on high-voltage-activated (HVA) calcium current in small-diameter dorsal root ganglion (DRG) neurons. Using pharmacological approaches, we show for the first time that an MrgC agonist (JHU58) selectively and dose-dependently inhibits N-type, but not L- or P/Q-type, HVA calcium channels in mouse DRG neurons. Activation of HVA calcium channels is important to neurotransmitter release and synaptic transmission. Patch-clamp recordings in spinal cord slices showed that JHU58 attenuated the evoked excitatory postsynaptic currents in substantia gelatinosa (SG) neurons in wild-type mice, but not in Mrg knockout mice, after peripheral nerve injury. These findings indicate that activation of endogenously expressed MrgC receptors at central terminals of primary sensory fibers may decrease peripheral excitatory inputs onto SG neurons. Together, these results suggest potential cellular and molecular mechanisms that may contribute to intrathecal MrgC agonist-induced analgesia. Because MrgC shares substantial genetic homogeneity with human MrgX1, our findings may suggest a rationale for developing intrathecally delivered MrgX1 receptor agonists to treat pathological pain in humans and provide critical insight regarding potential mechanisms that may underlie its analgesic effects.
Collapse
Affiliation(s)
- Zhe Li
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Qian Xu
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Fei Yang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Vinod Tiwari
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Qin Liu
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Zongxiang Tang
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Liang Han
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Yu-Xia Chu
- Department of Neural and Pain Sciences, Program in Neuroscience, Dental School, University of Maryland, Baltimore, Maryland, 21201
| | - Yun Wang
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Niyada Hin
- Brain Science Institute, Johns Hopkins University, Baltimore, Maryland, 21205
| | - Takashi Tsukamoto
- Brain Science Institute, Johns Hopkins University, Baltimore, Maryland, 21205
- Department of Neurology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Barbara Slusher
- Brain Science Institute, Johns Hopkins University, Baltimore, Maryland, 21205
- Department of Neurology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Xiaowei Guan
- Department of Human Anatomy, Nanjing Medical University, Nanjing, 210029, China
| | - Feng Wei
- Department of Neural and Pain Sciences, Program in Neuroscience, Dental School, University of Maryland, Baltimore, Maryland, 21201
| | - Srinivasa N Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
- Howard Hughes Medical Institute, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21287
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, 21205
| |
Collapse
|