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Sensory neuron-expressed TRPC3 mediates acute and chronic itch. Pain 2023; 164:98-110. [PMID: 35507377 DOI: 10.1097/j.pain.0000000000002668] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/20/2022] [Indexed: 01/09/2023]
Abstract
ABSTRACT Chronic pruritus is a prominent symptom of allergic contact dermatitis (ACD) and represents a huge unmet health problem. However, its underlying cellular and molecular mechanisms remain largely unexplored. TRPC3 is highly expressed in primary sensory neurons and has been implicated in peripheral sensitization induced by proinflammatory mediators. Yet, the role of TRPC3 in acute and chronic itch is still not well defined. Here, we show that, among mouse trigeminal ganglion (TG) neurons, Trpc3 mRNA is predominantly expressed in nonpeptidergic small diameter TG neurons of mice. Moreover, Trpc3 mRNA signal was present in most presumptively itch sensing neurons. TRPC3 agonism induced TG neuronal activation and acute nonhistaminergic itch-like and pain-like behaviors in naive mice. In addition, genetic deletion of Trpc3 attenuated acute itch evoked by certain common nonhistaminergic pruritogens, including endothelin-1 and SLIGRL-NH2. In a murine model of contact hypersensitivity (CHS), the Trpc3 mRNA expression level and function were upregulated in the TG after CHS. Pharmacological inhibition and global knockout of Trpc3 significantly alleviated spontaneous scratching behaviors without affecting concurrent cutaneous inflammation in the CHS model. Furthermore, conditional deletion of Trpc3 in primary sensory neurons but not in keratinocytes produced similar antipruritic effects in this model. These findings suggest that TRPC3 expressed in primary sensory neurons may contribute to acute and chronic itch through a histamine independent mechanism and that targeting neuronal TRPC3 might benefit the treatment of chronic itch associated with ACD and other inflammatory skin disorders.
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Berhane I, Hin N, Thomas AG, Huang Q, Zhang C, Veeravalli V, Wu Y, Ng J, Alt J, Rojas C, Hihara H, Aoki M, Yoshizawa K, Nishioka T, Suzuki S, He SQ, Peng Q, Guan Y, Dong X, Raja SN, Slusher BS, Rais R, Tsukamoto T. Thieno[2,3- d]pyrimidine-Based Positive Allosteric Modulators of Human Mas-Related G Protein-Coupled Receptor X1 (MRGPRX1). J Med Chem 2022; 65:3218-3228. [PMID: 35119273 PMCID: PMC9176367 DOI: 10.1021/acs.jmedchem.1c01709] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mas-related G protein-coupled receptor X1 (MRGPRX1) is a human sensory neuron-specific receptor and potential target for the treatment of pain. Positive allosteric modulators (PAMs) of MRGPRX1 have the potential to preferentially activate the receptors at the central terminals of primary sensory neurons and minimize itch side effects caused by peripheral activation. Using a high-throughput screening (HTS) hit, a series of thieno[2,3-d]pyrimidine-based molecules were synthesized and evaluated as human MRGPRX1 PAMs in HEK293 cells stably transfected with human MrgprX1 gene. An iterative process to improve potency and metabolic stability led to the discovery of orally available 6-(tert-butyl)-5-(3,4-dichlorophenyl)-4-(2-(trifluoromethoxy)phenoxy)thieno[2,3-d]pyrimidine (1t), which can be distributed to the spinal cord, the presumed site of action, following oral administration. In a neuropathic pain model induced by sciatic nerve chronic constriction injury (CCI), compound 1t (100 mg/kg, po) reduced behavioral heat hypersensitivity in humanized MRGPRX1 mice, demonstrating the therapeutic potential of MRGPRX1 PAMs in treating neuropathic pain.
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Affiliation(s)
- Ilyas Berhane
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA,Department of Neurology, Johns Hopkins University,
Baltimore, MD 21205, USA
| | - Niyada Hin
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - Ajit G. Thomas
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - Qian Huang
- Department of Anesthesiology and Critical Care
Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Chi Zhang
- Department of Anesthesiology and Critical Care
Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Vijayabhaskar Veeravalli
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA,Department of Neurology, Johns Hopkins University,
Baltimore, MD 21205, USA
| | - Ying Wu
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - Justin Ng
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - Jesse Alt
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - Camilo Rojas
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - 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
| | - Shao-Qiu He
- Department of Anesthesiology and Critical Care
Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Qi Peng
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care
Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Xinzhong Dong
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - Srinivasa N. Raja
- Department of Anesthesiology and Critical Care
Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Barbara S. Slusher
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA,Department of Neurology, Johns Hopkins University,
Baltimore, MD 21205, USA,Solomon H. Snyder Department of Neuroscience, Johns Hopkins
University, Baltimore, MD 21205, USA
| | - Rana Rais
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA,Department of Neurology, Johns Hopkins University,
Baltimore, MD 21205, USA
| | - Takashi Tsukamoto
- Johns Hopkins Drug Discovery, Johns Hopkins
University, Baltimore, MD 21205, USA,Department of Neurology, Johns Hopkins University,
Baltimore, MD 21205, USA
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3
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Hami J, von Bohlen Und Halbach V, Tetzner A, Walther T, von Bohlen Und Halbach O. Localization and expression of the Mas-related G-protein coupled receptor member D (MrgD) in the mouse brain. Heliyon 2021; 7:e08440. [PMID: 34901497 PMCID: PMC8637488 DOI: 10.1016/j.heliyon.2021.e08440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 07/21/2021] [Accepted: 11/16/2021] [Indexed: 11/23/2022] Open
Abstract
Numerous studies in the last decades have provided evidence for the existence of a local renin-angiotensin system (RAS) in the central nervous system (CNS). Widespread distribution of the different RAS components in the brain demonstrates the pleiotropic role of this system in the structure and function of CNS. With the advent of new molecular techniques, a novel receptor has been identified within the beneficial arm of the RAS, the Mas-related G-protein coupled receptor D (MrgD), which can be stimulated by two heptapeptides, Ala1-(Ang-(1-7), also named alamandine, and Ang-(1-7). However, the biological and physiological relevance of this interaction remains obscure. Since several recent studies hinted at a role of MrgD in the CNS, we determined the distribution pattern of MrgD receptors in the adult mouse brain by using a genetic mouse model with tracers of MrgD expression. MrgD-positive cells could be identified in some forebrain areas, including cortex, hippocampus, amygdala, hypothalamus, habenular nuclei, striatum and pallidum, as well as in some mid-brain nuclei in a region-specific manner. The specific localization of MrgD in the reward- and limbic-related areas can hint at a role of MrgD in processes such as pain perception/modulation, synaptic plasticity, learning, memory and cognition.
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Affiliation(s)
- Javad Hami
- Institut für Anatomie und Zellbiologie, Universitätsmedizin Greifswald, 17489 Greifswald, Germany
| | | | - Anja Tetzner
- Department Pharmacology and Therapeutics, School of Medicine and School of Pharmacy, University College Cork (UCC), Cork, Ireland
| | - Thomas Walther
- Department Pharmacology and Therapeutics, School of Medicine and School of Pharmacy, University College Cork (UCC), Cork, Ireland.,Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
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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.
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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
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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.
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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
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6
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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.
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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.
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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.
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Yang F, Duan W, Huang Q, Chen Z, Ford N, Gao X, Sivanesan E, Sarma SV, Vera-Portocarrero LP, Linderoth B, Raja SN, Guan Y. Modulation of Spinal Nociceptive Transmission by Sub-Sensory Threshold Spinal Cord Stimulation in Rats After Nerve Injury. Neuromodulation 2019; 23:36-45. [PMID: 31162783 DOI: 10.1111/ner.12975] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/10/2019] [Accepted: 05/01/2019] [Indexed: 01/23/2023]
Abstract
OBJECTIVES High-frequency spinal cord stimulation (SCS) administered below the sensory threshold (subparesthetic) can inhibit pain, but the mechanisms remain obscure. We examined how different SCS paradigms applied at intensities below the threshold of Aβ-fiber activation (sub-sensory threshold) affect spinal nociceptive transmission in rats after an L5 spinal nerve ligation (SNL). MATERIALS AND METHODS Electrophysiology was used to record local field potential (LFP) at L4 spinal cord before, during, and 0-60 min after SCS in SNL rats. LFP was evoked by high-intensity paired-pulse test stimulation (5 mA, 0.2 msec, 400 msec interval) at the sciatic nerve. Epidural SCS was delivered through a miniature electrode placed at T13-L1 and L2-L3 spinal levels. Four patterns of SCS (200 Hz, 1 msec; 500 Hz, 0.5 msec; 1200 Hz; 0.2 msec; 10,000 Hz, 0.024 msec, 30 min, bipolar) were tested at 90% Aβ-threshold as a subthreshold intensity. As a positive control, traditional SCS (50 Hz, 0.2 msec) was tested at 100% Aβ-plateau as a suprathreshold intensity. RESULTS Traditional suprathreshold SCS at T13-L1 level significantly reduced LFP to C-fiber inputs (C-LFP). Subthreshold SCS of 200 and 500 Hz, but not 1200 or 10,000 Hz, also reduced C-LFP, albeit to a lesser extent than did traditional SCS (n = 7-10/group). When SCS was applied at the L2-L3 level, only traditional SCS and subthreshold SCS of 200 Hz inhibited C-LFP (n = 8-10/group). CONCLUSIONS Traditional suprathreshold SCS acutely inhibits spinal nociceptive transmission. Low-frequency subthreshold SCS with a long pulse width (200 Hz, 1 msec), but not higher-frequency SCS, also attenuates C-LFP.
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Affiliation(s)
- Fei Yang
- Department of Neurobiology, School of Basic Medical Sciences, Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China.,Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Wanru Duan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.,Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Qian Huang
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Zhiyong Chen
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Neil Ford
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Xinyan Gao
- Institute of Acupuncture and Moxibustion, China Academy of Chinese Medical Sciences, Beijing, China
| | - Eellan Sivanesan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Sridevi V Sarma
- Department of Biomedical Engineering, Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA
| | | | - Bengt Linderoth
- Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden
| | - Srinivasa N Raja
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
| | - Yun Guan
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University, School of Medicine, Baltimore, MD, USA.,Department of Neurological Surgery, Johns Hopkins University, School of Medicine, Baltimore, MD, USA
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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.
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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.
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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.
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11
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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: 52] [Impact Index Per Article: 7.4] [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.
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12
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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.
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13
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Amen AM, Ruiz-Garzon CR, Shi J, Subramanian M, Pham DL, Meffert MK. A Rapid Induction Mechanism for Lin28a in Trophic Responses. Mol Cell 2017; 65:490-503.e7. [PMID: 28132840 DOI: 10.1016/j.molcel.2016.12.025] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 11/14/2016] [Accepted: 12/23/2016] [Indexed: 12/24/2022]
Abstract
Environmental cues provoke rapid transitions in gene expression to support growth and cellular plasticity through incompletely understood mechanisms. Lin28 RNA-binding proteins have evolutionarily conserved roles in post-transcriptional coordination of pro-growth gene expression, but signaling pathways allowing trophic stimuli to induce Lin28 have remained uncharacterized. We find that Lin28a protein exhibits rapid basal turnover in neurons and that mitogen-activated protein kinase (MAPK)-dependent phosphorylation of the RNA-silencing factor HIV TAR-RNA-binding protein (TRBP) promotes binding and stabilization of Lin28a, but not Lin28b, with an accompanying reduction in Lin28-regulated miRNAs, downstream of brain-derived neurotrophic factor (BDNF). Binding of Lin28a to TRBP in vitro is also enhanced by phospho-mimic TRBP. Further, phospho-TRBP recapitulates BDNF-induced neuronal dendritic spine growth in a Lin28a-dependent manner. Finally, we demonstrate MAPK-dependent TRBP and Lin28a induction, with physiological function in growth and survival, downstream of diverse growth factors in multiple primary cell types, supporting a broad role for this pathway in trophic responses.
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Affiliation(s)
- Alexandra M Amen
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Claudia R Ruiz-Garzon
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jay Shi
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Megha Subramanian
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daniel L Pham
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Mollie K Meffert
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA; Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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14
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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
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15
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Rohacs T. Phosphoinositide signaling in somatosensory neurons. Adv Biol Regul 2016; 61:2-16. [PMID: 26724974 PMCID: PMC4884561 DOI: 10.1016/j.jbior.2015.11.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/06/2015] [Accepted: 11/07/2015] [Indexed: 02/03/2023]
Abstract
Somatosensory neurons of the dorsal root ganglia (DRG) and trigeminal ganglia (TG) are responsible for detecting thermal and tactile stimuli. They are also the primary neurons mediating pain and itch. A large number of cell surface receptors in these neurons couple to phospholipase C (PLC) enzymes leading to the hydrolysis of phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] and the generation of downstream signaling molecules. These neurons also express many different ion channels, several of which are regulated by phosphoinositides. This review will summarize the knowledge on phosphoinositide signaling in DRG neurons, with special focus on effects on sensory and other ion channels.
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Affiliation(s)
- Tibor Rohacs
- Rutgers, New Jersey Medical School, Newark, NJ, USA.
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16
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Abstract
PURPOSE OF REVIEW To provide an overview on drug targets and emerging pharmacological treatment options for chronic pain. RECENT FINDINGS Chronic pain poses an enormous socioeconomic burden for the more than 30% of people who suffer from it, costing over $600 billion per year in the USA. In recent years, there has been a surge in preclinical and clinical research endeavors to try to stem this epidemic. Preclinical studies have identified a wide array of potential targets, with some of the most promising translational research being performed on novel opioid receptors, cannabinoid receptors, selective ion channel blockers, cytokine inhibitors, nerve growth factor inhibitors, N-methyl-D-aspartate receptor antagonists, glial cell inhibitors, and bisphosphonates. SUMMARY There are many obstacles for the development of effective medications to treat chronic pain, including the inherent challenges in identifying pathophysiological mechanisms, the overlap and multiplicity of pain pathways, and off-target adverse effects stemming from the ubiquity of drug target receptor sites and the lack of highly selective receptor ligands. Despite these barriers, the number and diversity of potential therapies have continued to grow, to include disease-modifying and individualized drug treatments.
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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]
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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.
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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.
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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.
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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
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20
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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.
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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.
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ZC88, a novel N-type calcium channel blocker from 4-amino-piperidine derivatives state-dependent inhibits Cav2.2 calcium channels. Brain Res 2015; 1605:12-21. [DOI: 10.1016/j.brainres.2015.01.054] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Revised: 01/22/2015] [Accepted: 01/23/2015] [Indexed: 11/23/2022]
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22
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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.
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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)
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