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Hawker P, Zhang L, Liu L. Mas-related G protein-coupled receptors in gastrointestinal dysfunction and inflammatory bowel disease: A review. Br J Pharmacol 2024; 181:2197-2211. [PMID: 36787888 DOI: 10.1111/bph.16059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 12/25/2022] [Accepted: 02/04/2023] [Indexed: 02/16/2023] Open
Abstract
Inflammatory bowel disease (IBD) is a chronic debilitating condition, hallmarked by persistent inflammation of the gastrointestinal tract. Despite recent advances in clinical treatments, the aetiology of IBD is unknown, and a large proportion of patients are refractory to pharmacotherapy. Understanding IBD immunopathogenesis is crucial to discern the cause of IBD and optimise treatments. Mas-related G protein-coupled receptors (Mrgprs) are a family of approximately 50 G protein-coupled receptors that were first identified over 20 years ago. Originally known for their expression in skin nociceptors and their role in transmitting the sensation of itch in the periphery, new reports have described the presence of Mrgprs in the gastrointestinal tract. In this review, we consider the impact of these findings and assess the evidence that suggests that Mrgprs may be involved in the disrupted homeostatic processes that contribute to gastrointestinal disorders and IBD. LINKED ARTICLES: This article is part of a themed issue Therapeutic Targeting of G Protein-Coupled Receptors: hot topics from the Australasian Society of Clinical and Experimental Pharmacologists and Toxicologists 2021 Virtual Annual Scientific Meeting. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v181.14/issuetoc.
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Affiliation(s)
- Patrick Hawker
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Li Zhang
- School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales, Australia
| | - Lu Liu
- School of Medical Sciences, University of New South Wales, Sydney, New South Wales, Australia
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2
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Wong TK, Choi YG, Li PH, Chow BKC, Kumar M. MRGPRX2 antagonist GE1111 attenuated DNFB-induced atopic dermatitis in mice by reducing inflammatory cytokines and restoring skin integrity. Front Immunol 2024; 15:1406438. [PMID: 38817611 PMCID: PMC11137259 DOI: 10.3389/fimmu.2024.1406438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2024] [Accepted: 04/26/2024] [Indexed: 06/01/2024] Open
Abstract
Introduction Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterised by itching, erythema, and epidermal barrier dysfunction. The pathogenesis of AD is complex and multifactorial; however,mast cell (MC) activation has been reported to be one of the crucial mechanisms in the pathogenesis of AD. The MC receptor Mas related G protein-coupled receptor-X2 (MRGPRX2) has been identified as a prominent alternative receptor to the IgE receptor in causing MC activation and the subsequent release of inflammatory mediators. The current study aimed to evaluate the therapeutic effect of a novel small molecule MRGPRX2 antagonist GE1111 in AD using in vitro and in vivo approaches. Methods We developed an in vitro cell culture disease model by using LAD-2 MC, HaCaT keratinocytes and RAW 264.7 macrophage cell lines. We challenged keratinocytes and macrophage cells with CST-14 treated MC supernatant in the presence and absence of GE1111 and measured the expression of tight junction protein claudin 1, inflammatory cytokines and macrophage phagocytosis activity through immunohistochemistry, western blotting, RT-qPCR and fluorescence imaging techniques. In addition to this, we developed a DFNB-induced AD model in mice and evaluated the protective effect and underlying mechanism of GE1111. Results and Discussion Our in vitro findings demonstrated a potential therapeutic effect of GE1111, which inhibits the expression of TSLP, IL-13, MCP-1, TNF-a, and IL-1ß in MC and keratinocytes. In addition to this, GE1111 was able to preserve the expression of claudin 1 in keratinocytes and the phagocytotic activity of macrophage cells. The in vivo results demonstrated that GE1111 treatment significantly reduced phenotypic changes associated with AD (skin thickening, scaling, erythema and epidermal thickness). Furthermore, immunohistochemical analysis demonstrated that GE1111 treatment preserved the expression of the tight junction protein Involucrin and reduced the expression of the inflammatory mediator periostin in the mouse model of AD. These findings were supported by gene and protein expression analysis, where GE1111 treatment reduced the expression of TSLP, IL-13, and IL-1ß, as well as downstream signalling pathways of MRGPRX2 in AD skin lesions. In conclusion, our findings provide compelling in vitro and in vivo evidence supporting the contribution of MRGPRX2-MC interaction with keratinocytes and macrophages in the pathogenesis of AD.
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Affiliation(s)
- Trevor K. Wong
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
- Faculty of Health Sciences, McMaster University, Hamliton, ON, Canada
| | - Ye Gi Choi
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Philip H. Li
- Division of Rheumatology and Clinical Immunology, Department of Medicine, Queen Mary Hospital, University of Hong Kong, Hong Kong SAR, China
| | - Billy K. C. Chow
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
| | - Mukesh Kumar
- School of Biological Sciences, The University of Hong Kong, Hong Kong, Hong Kong SAR, China
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3
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Chien DCC, Limjunyawong N, Cao C, Meixiong J, Peng Q, Ho CY, Fay JF, Roth BL, Dong X. MRGPRX4 mediates phospho-drug-associated pruritus in a humanized mouse model. Sci Transl Med 2024; 16:eadk8198. [PMID: 38718132 DOI: 10.1126/scitranslmed.adk8198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Accepted: 04/12/2024] [Indexed: 05/30/2024]
Abstract
The phosphate modification of drugs is a common chemical strategy to increase solubility and allow for parenteral administration. Unfortunately, phosphate modifications often elicit treatment- or dose-limiting pruritus through an unknown mechanism. Using unbiased high-throughput drug screens, we identified the Mas-related G protein-coupled receptor X4 (MRGPRX4), a primate-specific, sensory neuron receptor previously implicated in itch, as a potential target for phosphate-modified compounds. Using both Gq-mediated calcium mobilization and G protein-independent GPCR assays, we found that phosphate-modified compounds potently activate MRGPRX4. Furthermore, a humanized mouse model expressing MRGPRX4 in sensory neurons exhibited robust phosphomonoester prodrug-evoked itch. To characterize and confirm this interaction, we further determined the structure of MRGPRX4 in complex with a phosphate-modified drug through single-particle cryo-electron microscopy (cryo-EM) and identified critical amino acid residues responsible for the binding of the phosphate group. Together, these findings explain how phosphorylated drugs can elicit treatment-limiting itch and identify MRGPRX4 as a potential therapeutic target to suppress itch and to guide future drug design.
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Affiliation(s)
- Daphne Chun-Che Chien
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nathachit Limjunyawong
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Can Cao
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - James Meixiong
- Department of Dermatology, University of California San Francisco, San Francisco, CA 94115, USA
| | - Qi Peng
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Cheng-Ying Ho
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jonathan F Fay
- Department of Biochemistry and Molecular Biology, University of Maryland Baltimore, Baltimore, MD 21201, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27599, USA
| | - Xinzhong Dong
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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4
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Balzulat A, Zhu WF, Flauaus C, Hernandez‐Olmos V, Heering J, Sethumadhavan S, Dubiel M, Frank A, Menge A, Hebchen M, Metzner K, Lu R, Lukowski R, Ruth P, Knapp S, Müller S, Steinhilber D, Hänelt I, Stark H, Proschak E, Schmidtko A. Discovery of a Small Molecule Activator of Slack (Kcnt1) Potassium Channels That Significantly Reduces Scratching in Mouse Models of Histamine-Independent and Chronic Itch. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2307237. [PMID: 38350720 PMCID: PMC11022729 DOI: 10.1002/advs.202307237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/15/2024] [Indexed: 02/15/2024]
Abstract
Various disorders are accompanied by histamine-independent itching, which is often resistant to the currently available therapies. Here, it is reported that the pharmacological activation of Slack (Kcnt1, KNa1.1), a potassium channel highly expressed in itch-sensitive sensory neurons, has therapeutic potential for the treatment of itching. Based on the Slack-activating antipsychotic drug, loxapine, a series of new derivatives with improved pharmacodynamic and pharmacokinetic profiles is designed that enables to validate Slack as a pharmacological target in vivo. One of these new Slack activators, compound 6, exhibits negligible dopamine D2 and D3 receptor binding, unlike loxapine. Notably, compound 6 displays potent on-target antipruritic activity in multiple mouse models of acute histamine-independent and chronic itch without motor side effects. These properties make compound 6 a lead molecule for the development of new antipruritic therapies targeting Slack.
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Affiliation(s)
- Annika Balzulat
- Institute of Pharmacology and Clinical PharmacyGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
| | - W. Felix Zhu
- Institute of Pharmaceutical ChemistryGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
| | - Cathrin Flauaus
- Institute of Pharmacology and Clinical PharmacyGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
| | - Victor Hernandez‐Olmos
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMPTheodor‐Stern‐Kai 760596Frankfurt am MainGermany
| | - Jan Heering
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMPTheodor‐Stern‐Kai 760596Frankfurt am MainGermany
| | - Sunesh Sethumadhavan
- Institute of BiochemistryGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
| | - Mariam Dubiel
- Institute of Pharmaceutical and Medicinal ChemistryHeinrich Heine University DüsseldorfUniversitätsstr. 140225DüsseldorfGermany
| | - Annika Frank
- Institute of Pharmaceutical and Medicinal ChemistryHeinrich Heine University DüsseldorfUniversitätsstr. 140225DüsseldorfGermany
| | - Amelie Menge
- Institute of Pharmaceutical ChemistryGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
- Structural Genomics Consortium (SGC)Buchmann Institute for Molecular Life SciencesGoethe University FrankfurtMax‐von‐Laue‐Str. 1560438Frankfurt am MainGermany
| | - Maureen Hebchen
- Institute of Pharmacology and Clinical PharmacyGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
| | - Katharina Metzner
- Institute of Pharmacology and Clinical PharmacyGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
| | - Ruirui Lu
- Institute of Pharmacology and Clinical PharmacyGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
| | - Robert Lukowski
- Department of PharmacologyToxicology and Clinical PharmacyInstitute of Pharmacy University of TübingenAuf der Morgenstelle 872076TübingenGermany
| | - Peter Ruth
- Department of PharmacologyToxicology and Clinical PharmacyInstitute of Pharmacy University of TübingenAuf der Morgenstelle 872076TübingenGermany
| | - Stefan Knapp
- Institute of Pharmaceutical ChemistryGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
- Structural Genomics Consortium (SGC)Buchmann Institute for Molecular Life SciencesGoethe University FrankfurtMax‐von‐Laue‐Str. 1560438Frankfurt am MainGermany
| | - Susanne Müller
- Institute of Pharmaceutical ChemistryGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
- Structural Genomics Consortium (SGC)Buchmann Institute for Molecular Life SciencesGoethe University FrankfurtMax‐von‐Laue‐Str. 1560438Frankfurt am MainGermany
| | - Dieter Steinhilber
- Institute of Pharmaceutical ChemistryGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMPTheodor‐Stern‐Kai 760596Frankfurt am MainGermany
| | - Inga Hänelt
- Institute of BiochemistryGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
| | - Holger Stark
- Institute of Pharmaceutical and Medicinal ChemistryHeinrich Heine University DüsseldorfUniversitätsstr. 140225DüsseldorfGermany
| | - Ewgenij Proschak
- Institute of Pharmaceutical ChemistryGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
- Fraunhofer Institute for Translational Medicine and Pharmacology ITMPTheodor‐Stern‐Kai 760596Frankfurt am MainGermany
| | - Achim Schmidtko
- Institute of Pharmacology and Clinical PharmacyGoethe University FrankfurtMax‐von‐Laue‐Str. 960438Frankfurt am MainGermany
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5
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Gour N, Yong HM, Magesh A, Atakkatan A, Andrade F, Lajoie S, Dong X. A GPCR-neuropeptide axis dampens hyperactive neutrophils by promoting an alternative-like polarization during bacterial infection. Immunity 2024; 57:333-348.e6. [PMID: 38295799 PMCID: PMC10940224 DOI: 10.1016/j.immuni.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2023] [Revised: 10/10/2023] [Accepted: 01/08/2024] [Indexed: 02/16/2024]
Abstract
The notion that neutrophils exist as a homogeneous population is being replaced with the knowledge that neutrophils adopt different functional states. Neutrophils can have a pro-inflammatory phenotype or an anti-inflammatory state, but how these states are regulated remains unclear. Here, we demonstrated that the neutrophil-expressed G-protein-coupled receptor (GPCR) Mrgpra1 is a negative regulator of neutrophil bactericidal functions. Mrgpra1-mediated signaling was driven by its ligand, neuropeptide FF (NPFF), which dictated the balance between pro- and anti-inflammatory programming. Specifically, the Mrgpra1-NPFF axis counter-regulated interferon (IFN) γ-mediated neutrophil polarization during acute lung infection by favoring an alternative-like polarization, suggesting that it may act to balance overzealous neutrophilic responses. Distinct, cross-regulated populations of neutrophils were the primary source of NPFF and IFNγ during infection. As a subset of neutrophils at steady state expressed NPFF, these findings could have broad implications in various infectious and inflammatory diseases. Therefore, a neutrophil-intrinsic pathway determines their cellular fate, function, and magnitude of infection.
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Affiliation(s)
- Naina Gour
- Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Hwan Mee Yong
- Department of Environmental Health and Engineering, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Aishwarya Magesh
- Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, MD, USA; Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Aishwarya Atakkatan
- Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA; Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Felipe Andrade
- Division of Rheumatology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Stephane Lajoie
- Department of Otolaryngology, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Xinzhong Dong
- Solomon H. Snyder Department of Neuroscience, School of Medicine, Johns Hopkins University, Baltimore, MD, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA.
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6
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Auyeung KL, Kim BS. Emerging concepts in neuropathic and neurogenic itch. Ann Allergy Asthma Immunol 2023; 131:561-566. [PMID: 37597692 PMCID: PMC10840634 DOI: 10.1016/j.anai.2023.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 08/04/2023] [Accepted: 08/07/2023] [Indexed: 08/21/2023]
Abstract
Chronic pruritus has multiple etiologies, ranging from inflammatory to metabolic and neuropathic processes. However, recent advances in itch biology have shed light on potential mechanisms that explain the molecular and cellular basis of these pathologies. Furthermore, new understanding of neuroimmune itch circuits necessitates clarification of terminologies such as "neuropathic" and "neurogenic." This review provides an overview of ways new concepts may better explain the pathophysiology of a variety of chronic pruritic disorders and the rationale for directing emerging novel therapeutic strategies toward them.
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Affiliation(s)
- Kelsey L Auyeung
- Kimberly and Eric J. Waldman Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Brian S Kim
- Kimberly and Eric J. Waldman Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, New York; Mark Lebwohl Center for Neuroinflammation & Sensation, Icahn School of Medicine at Mount Sinai, New York, New York; Marc and Jennifer Lipschultz Precision Immunology Institute, Icahn School of Medicine at Mount Sinai, New York, New York; Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York.
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7
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Kume M, Ahmad A, DeFea KA, Vagner J, Dussor G, Boitano S, Price TJ. Protease-Activated Receptor 2 (PAR2) Expressed in Sensory Neurons Contributes to Signs of Pain and Neuropathy in Paclitaxel Treated Mice. THE JOURNAL OF PAIN 2023; 24:1980-1993. [PMID: 37315729 PMCID: PMC10615692 DOI: 10.1016/j.jpain.2023.06.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2023] [Revised: 05/26/2023] [Accepted: 06/07/2023] [Indexed: 06/16/2023]
Abstract
Chemotherapy-induced peripheral neuropathy (CIPN) is a common, dose-limiting side effect of cancer therapy. Protease-activated receptor 2 (PAR2) is implicated in a variety of pathologies, including CIPN. In this study, we demonstrate the role of PAR2 expressed in sensory neurons in a paclitaxel (PTX)-induced model of CIPN in mice. PAR2 knockout/wildtype (WT) mice and mice with PAR2 ablated in sensory neurons were treated with PTX administered via intraperitoneal injection. In vivo behavioral studies were done in mice using von Frey filaments and the Mouse Grimace Scale. We then examined immunohistochemical staining of dorsal root ganglion (DRG) and hind paw skin samples from CIPN mice to measure satellite cell gliosis and intra-epidermal nerve fiber (IENF) density. The pharmacological reversal of CIPN pain was tested with the PAR2 antagonist C781. Mechanical allodynia caused by PTX treatment was alleviated in PAR2 knockout mice of both sexes. In the PAR2 sensory neuronal conditional knockout (cKO) mice, both mechanical allodynia and facial grimacing were attenuated in mice of both sexes. In the DRG of the PTX-treated PAR2 cKO mice, satellite glial cell activation was reduced compared to control mice. IENF density analysis of the skin showed that the PTX-treated control mice had a reduction in nerve fiber density while the PAR2 cKO mice had a comparable skin innervation as the vehicle-treated animals. Similar results were seen with satellite cell gliosis in the DRG, where gliosis induced by PTX was absent in PAR cKO mice. Finally, C781 was able to transiently reverse established PTX-evoked mechanical allodynia. PERSPECTIVE: Our work demonstrates that PAR2 expressed in sensory neurons plays a key role in PTX-induced mechanical allodynia, spontaneous pain, and signs of neuropathy, suggesting PAR2 as a possible therapeutic target in multiple aspects of PTX CIPN.
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Affiliation(s)
- Moeno Kume
- University of Texas at Dallas, Department of Neuroscience and Center for Advanced Pain Studies
| | - Ayesha Ahmad
- University of Texas at Dallas, Department of Neuroscience and Center for Advanced Pain Studies
| | | | | | - Gregory Dussor
- University of Texas at Dallas, Department of Neuroscience and Center for Advanced Pain Studies
| | - Scott Boitano
- University of Arizona Bio5 Research Institute
- University of Arizona Heath Sciences, Asthma and Airway Disease Research Center
- University of Arizona Heath Sciences, Department of Physiology
| | - Theodore J. Price
- University of Texas at Dallas, Department of Neuroscience and Center for Advanced Pain Studies
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8
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Guo L, Zhang Y, Fang G, Tie L, Zhuang Y, Xue C, Liu Q, Zhang M, Zhu K, You C, Xu P, Yuan Q, Zhang C, Liu L, Rong N, Peng S, Liu Y, Wang C, Luo X, Lv Z, Kang D, Yu X, Zhang C, Jiang Y, Dong X, Zhou J, Liu Z, Yang F, Eric Xu H, Sun JP. Ligand recognition and G protein coupling of the human itch receptor MRGPRX1. Nat Commun 2023; 14:5004. [PMID: 37591889 PMCID: PMC10435460 DOI: 10.1038/s41467-023-40705-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Accepted: 08/08/2023] [Indexed: 08/19/2023] Open
Abstract
MRGPRX1, a Mas-related GPCR (MRGPR), is a key receptor for itch perception and targeting MRGPRX1 may have potential to treat both chronic itch and pain. Here we report cryo-EM structures of the MRGPRX1-Gi1 and MRGPRX1-Gq trimers in complex with two peptide ligands, BAM8-22 and CNF-Tx2. These structures reveal a shallow orthosteric pocket and its conformational plasticity for sensing multiple different peptidic itch allergens. Distinct from MRGPRX2, MRGPRX1 contains a unique pocket feature at the extracellular ends of TM3 and TM4 to accommodate the peptide C-terminal "RF/RY" motif, which could serve as key mechanisms for peptidic allergen recognition. Below the ligand binding pocket, the G6.48XP6.50F6.51G6.52X(2)F/W6.55 motif is essential for the inward tilting of the upper end of TM6 to induce receptor activation. Moreover, structural features inside the ligand pocket and on the cytoplasmic side of MRGPRX1 are identified as key elements for both Gi and Gq signaling. Collectively, our studies provide structural insights into understanding itch sensation, MRGPRX1 activation, and downstream G protein signaling.
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Affiliation(s)
- Lulu Guo
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
- Key Laboratory of Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, China
| | - Yumu Zhang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Guoxing Fang
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Lu Tie
- Department of Pharmacology, School of Basic Medical Sciences, Peking University and Beijing Key Laboratory of Tumor Systems Biology, Peking University, Beijing, China
| | - Yuming Zhuang
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Chenyang Xue
- Department of Immunology and Microbiology, Southern University of Science and Technology, Shenzhen, Guangdong, China
| | - Qi Liu
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Minghui Zhang
- Key Laboratory of Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, China
| | - Kongkai Zhu
- Key Laboratory of Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, China
| | - Chongzhao You
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Peiyu Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Qingning Yuan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China
| | - Chao Zhang
- Key Laboratory of Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, China
| | - Lei Liu
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Naikang Rong
- Key Laboratory of Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, China
| | - Shengxuan Peng
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yuan Liu
- Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Chuanzheng Wang
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xin Luo
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Zongyao Lv
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Dongwei Kang
- Department of Medicinal Chemistry, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan, China
| | - Xiao Yu
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China
| | - Cheng Zhang
- Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, China
| | - Yi Jiang
- Lingang Laboratory, Shanghai, China
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Jiuyao Zhou
- Department of Pharmacology, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, China.
| | - Zhongmin Liu
- Department of Immunology and Microbiology, Southern University of Science and Technology, Shenzhen, Guangdong, China.
| | - Fan Yang
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China.
- Key Laboratory Experimental Teratology of the Ministry of Education and Department of Physiology, School of Basic Medical Sciences, Shandong University, Jinan, Shandong, China.
| | - H Eric Xu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
| | - Jin-Peng Sun
- Advanced Medical Research Institute, Cheeloo College of Medicine, Shandong University, Jinan, China.
- Key Laboratory of Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, China.
- Department of Pharmacology, School of Basic Medical Sciences, Peking University and Beijing Key Laboratory of Tumor Systems Biology, Peking University, Beijing, China.
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9
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Gan B, Yu L, Yang H, Jiao H, Pang B, Chen Y, Wang C, Lv R, Hu H, Cao Z, Ren R. Mechanism of agonist-induced activation of the human itch receptor MRGPRX1. PLoS Biol 2023; 21:e3001975. [PMID: 37347749 DOI: 10.1371/journal.pbio.3001975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 05/31/2023] [Indexed: 06/24/2023] Open
Abstract
Mas-related G-protein-coupled receptors X1-X4 (MRGPRX1-X4) are 4 primate-specific receptors that are recently reported to be responsible for many biological processes, including itch sensation, pain transmission, and inflammatory reactions. MRGPRX1 is the first identified human MRGPR, and its expression is restricted to primary sensory neurons. Due to its dual roles in itch and pain signaling pathways, MRGPRX1 has been regarded as a promising target for itch remission and pain inhibition. Here, we reported a cryo-electron microscopy (cryo-EM) structure of Gq-coupled MRGPRX1 in complex with a synthetic agonist compound 16 in an active conformation at an overall resolution of 3.0 Å via a NanoBiT tethering strategy. Compound 16 is a new pain-relieving compound with high potency and selectivity to MRGPRX1 over other MRGPRXs and opioid receptor. MRGPRX1 was revealed to share common structural features of the Gq-mediated receptor activation mechanism of MRGPRX family members, but the variable residues in orthosteric pocket of MRGPRX1 exhibit the unique agonist recognition pattern, potentially facilitating to design MRGPRX1-specific modulators. Together with receptor activation and itch behavior evaluation assays, our study provides a structural snapshot to modify therapeutic molecules for itch relieving and analgesia targeting MRGPRX1.
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Affiliation(s)
- Bing Gan
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
- The Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Leiye Yu
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Haifeng Yang
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Shenzhen Research Institute, Wuhan University, Shenzhen, China
| | - Haizhan Jiao
- The Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Bin Pang
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Yian Chen
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
| | - Chen Wang
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Rui Lv
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Hongli Hu
- The Kobilka Institute of Innovative Drug Discovery, School of Medicine, The Chinese University of Hong Kong, Shenzhen, Guangdong, China
| | - Zhijian Cao
- State Key Laboratory of Virology, College of Life Sciences, Wuhan University, Wuhan, China
- Shenzhen Research Institute, Wuhan University, Shenzhen, China
| | - Ruobing Ren
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
- Shanghai Qi Zhi Institute, Shanghai, China
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10
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Rodrigo M, Dong X, Chien D, Karnsakul W. Cholestatic Pruritus in Children: Conventional Therapies and Beyond. BIOLOGY 2023; 12:biology12050756. [PMID: 37237568 DOI: 10.3390/biology12050756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 05/12/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023]
Abstract
Pruritus in the setting of cholestatic liver disease is difficult to treat and occurs in patients ranging in age from infancy to adulthood. Likely multifactorial in etiology, this symptom often involves multimodal therapy targeting several pathways and mechanisms proposed in the underlying etiology of cholestatic pruritus. Many patients in both the pediatric and adult populations continue to experience unrelenting pruritus despite maximal conventional therapy. Options are further limited in treating pediatric patients due to sparse data regarding medication safety and efficacy in younger patients. Conventional therapies for the treatment of cholestatic pruritus in children include ursodeoxycholic acid, cholestyramine, hydroxyzine, and rifampin. Certain therapies are more routinely used in the adult populations but with limited data available for use in child and adolescent patients, including opioid antagonists and selective serotonin reuptake inhibitors. Recently, ileal bile acid transport inhibitors have been shown to alleviate pruritus in many children with Alagille syndrome and progressive familial intrahepatic cholestasis and is an additional therapy available for consideration for these patients. Ultimately, surgical options such as biliary diversion or liver transplantation are considered in specific circumstances when medical therapies have been exhausted and pruritus remains debilitating. While further investigation regarding underlying etiologies and effective therapies are needed to better understand itch pathogenesis and treatment in pediatric cholestasis, current considerations beyond conventional management include the use of opioid antagonists, selective serotonin reuptake inhibitors, ileal bile acid transport inhibitors, and surgical intervention.
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Affiliation(s)
- Minna Rodrigo
- Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xinzhong Dong
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Daphne Chien
- Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Wikrom Karnsakul
- Division of Pediatric Gastroenterology, Hepatology, and Nutrition, Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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11
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Ding Y, Dang B, Zhang Y, Hu S, Wang Y, Zhao C, Zhang T, Gao Z. Paeonol attenuates Substance P-induced urticaria by inhibiting Src kinase phosphorylation in mast cells. Cell Immunol 2023; 388-389:104728. [PMID: 37224634 DOI: 10.1016/j.cellimm.2023.104728] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Revised: 05/08/2023] [Accepted: 05/09/2023] [Indexed: 05/26/2023]
Abstract
BACKGROUND Treatment of chronic urticaria is challenging, the discovery of effective therapeutic drugs is urgently in demand. PURPOSE To study the effect and mechanism of Paeonol targeting mast cells and its therapeutic effect on chronic urticaria. STUDY DESIGN We developed a chronic urticaria model in vivo and mast cell model in vitro examined the effect of Paeonol in the treatment of chronic urticaria and its mechanism of action in mast cells. METHOD The anti-anaphylactoid effect of Paeonol was evaluated in PCA and systemic anaphylaxis models. The treatment role of Paeonol was studied in urticaria model. The release of cytokines and chemokines was measured using enzyme immunoassay kits. Western blot analysis was conducted to investigate phosphorylation of Src, PI3K, and PLC. In vitro kinase assays were conducted to investigate the kinase activity of Lyn, PLC, PI3K and Src. RESULTS In our study, Paeonol was able to attenuate evans blue leakage, serum histamine and chemokine release in a passive skin allergic reaction model. Simultaneously, Paeonol inhibited vasodilation and mast cell degranulation in C57BL/6 mice. Further research found that Paeonol alleviated symptoms such as erythema and rash in the Substance P-induced urticaria model, this is accompanied by inhibiting the release of related inflammatory factors. Validation experiments on mast cells in vitro found that Paeonol inhibited the activation of Src-PI3K/Lyn-PLC-NF-κB signaling pathway by crosslinking with Src kinase. Moreover, calcium influx, mast cell degranulation, cytokines generation and chemotaxis were reduced in LAD2 cells. Molecular docking experiments revealed that Paeonol is a specific antagonist targeting Src kinase in the treatment of skin diseases such as urticaria. CONCLUSION Paeonol, a herb-derived phenolic compound, can provide drug candidate for developing new drug in treatment of skin disease such as urticaria. SIGNIFICANCE STATEMENT In this study, we primarily examined the effect of Paeonol in the treatment of chronic urticaria and its mechanism of action in mast cells. Interestingly, Paeonol was found to regulate Src kinase activity downstream of MRGPRX2 triggered signaling cascade in mast cells. Therefore, this plant-derived phenolic compound may provide a therapeutic option for the treatment of chronic urticaria.
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Affiliation(s)
- Yuanyuan Ding
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Baowen Dang
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yonghui Zhang
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Shiting Hu
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Yuejin Wang
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Chenrui Zhao
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Tao Zhang
- College of Pharmacy, Xi'an Jiaotong University, Xi'an 710061, China
| | - Zijun Gao
- Department of Anesthesiology, Xi'an Honghui Hospital, Xi'an Jiaotong University, Xi'an 710054, China.
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12
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Liu Y, Cao C, Huang XP, Gumpper RH, Rachman MM, Shih SL, Krumm BE, Zhang S, Shoichet BK, Fay JF, Roth BL. Ligand recognition and allosteric modulation of the human MRGPRX1 receptor. Nat Chem Biol 2023; 19:416-422. [PMID: 36302898 DOI: 10.1038/s41589-022-01173-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 09/13/2022] [Indexed: 11/09/2022]
Abstract
The human MAS-related G protein-coupled receptor X1 (MRGPRX1) is preferentially expressed in the small-diameter primary sensory neurons and involved in the mediation of nociception and pruritus. Central activation of MRGPRX1 by the endogenous opioid peptide fragment BAM8-22 and its positive allosteric modulator ML382 has been shown to effectively inhibit persistent pain, making MRGPRX1 a promising target for non-opioid pain treatment. However, the activation mechanism of MRGPRX1 is still largely unknown. Here we report three high-resolution cryogenic electron microscopy structures of MRGPRX1-Gαq in complex with BAM8-22 alone, with BAM8-22 and ML382 simultaneously as well as with a synthetic agonist compound-16. These structures reveal the agonist binding mode for MRGPRX1 and illuminate the structural requirements for positive allosteric modulation. Collectively, our findings provide a molecular understanding of the activation and allosteric modulation of the MRGPRX1 receptor, which could facilitate the structure-based design of non-opioid pain-relieving drugs.
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Affiliation(s)
- Yongfeng Liu
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Can Cao
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Xi-Ping Huang
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Ryan H Gumpper
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Moira M Rachman
- Department of Pharmaceutical Sciences, University of California, San Francisco School of Medicine, San Francisco, CA, USA
| | - Sheng-Luen Shih
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Brian E Krumm
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Shicheng Zhang
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA
| | - Brian K Shoichet
- Department of Pharmaceutical Sciences, University of California, San Francisco School of Medicine, San Francisco, CA, USA
| | - Jonathan F Fay
- Department of Biochemistry and Biophysics, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- National Institute of Mental Health Psychoactive Drug Screening Program, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
- Division of Chemical Biology and Medicinal Chemistry, University of North Carolina School of Medicine, Chapel Hill, NC, USA.
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13
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Cao C, Roth BL. The structure, function, and pharmacology of MRGPRs. Trends Pharmacol Sci 2023; 44:237-251. [PMID: 36870785 PMCID: PMC10066734 DOI: 10.1016/j.tips.2023.02.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/01/2023] [Accepted: 02/09/2023] [Indexed: 03/06/2023]
Abstract
Mas-related G protein-coupled receptor (MRGPR) family members play important roles in the sensation of noxious stimuli and represent novel targets for the treatment of itch and pain. MRGPRs recognize a diversity of agonists and display complicated downstream signaling profiles, high sequence diversity across species, and many polymorphisms in humans. The recent structural advances on MRGPRs reveal unique structural features and diverse agonist recognition modes of this receptor family, which should facilitate the structure-based drug discovery at MRGPRs. In addition, the newly discovered ligands also provide valuable tools to explore the function and the therapeutic potential of MRGPRs. In this review, we discuss these progresses in our understanding of MRGPRs and highlight the challenges and potential opportunities for the future drug discovery at these receptors.
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Affiliation(s)
- Can Cao
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA
| | - Bryan L Roth
- Department of Pharmacology, University of North Carolina School of Medicine, Chapel Hill, NC 27599, USA; Division of Chemical Biology and Medicinal Chemistry, Eschelman School of Pharmacy and NIMH Psychoactive Drug Screening Program, University of North Carolina, Chapel Hill, NC 27599, USA.
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14
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Zhu Z, Bhatia M. Inflammation and Organ Injury the Role of Substance P and Its Receptors. Int J Mol Sci 2023; 24:ijms24076140. [PMID: 37047113 PMCID: PMC10094202 DOI: 10.3390/ijms24076140] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 03/17/2023] [Accepted: 03/22/2023] [Indexed: 04/14/2023] Open
Abstract
Tightly controlled inflammation is an indispensable mechanism in the maintenance of cellular and organismal homeostasis in living organisms. However, aberrant inflammation is detrimental and has been suggested as a key contributor to organ injury with different etiologies. Substance P (SP) is a neuropeptide with a robust effect on inflammation. The proinflammatory effects of SP are achieved by activating its functional receptors, namely the neurokinin 1 receptor (NK1R) receptor and mas-related G protein-coupled receptors X member 2 (MRGPRX2) and its murine homolog MRGPRB2. Upon activation, the receptors further signal to several cellular signaling pathways involved in the onset, development, and progression of inflammation. Therefore, excessive SP-NK1R or SP-MRGPRX2/B2 signals have been implicated in the pathogenesis of inflammation-associated organ injury. In this review, we summarize our current knowledge of SP and its receptors and the emerging roles of the SP-NK1R system and the SP-MRGPRX2/B2 system in inflammation and injury in multiple organs resulting from different pathologies. We also briefly discuss the prospect of developing a therapeutic strategy for inflammatory organ injury by disrupting the proinflammatory actions of SP via pharmacological intervention.
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Affiliation(s)
- Zhixing Zhu
- Department of Pathology and Biomedical Science, University of Otago, Christchurch 8140, New Zealand
| | - Madhav Bhatia
- Department of Pathology and Biomedical Science, University of Otago, Christchurch 8140, New Zealand
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15
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Koumaki D, Gregoriou S, Evangelou G, Krasagakis K. Pruritogenic Mediators and New Antipruritic Drugs in Atopic Dermatitis. J Clin Med 2023; 12:2091. [PMID: 36983094 PMCID: PMC10054239 DOI: 10.3390/jcm12062091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 02/27/2023] [Accepted: 03/01/2023] [Indexed: 03/30/2023] Open
Abstract
Atopic dermatitis (AD) is a common highly pruritic chronic inflammatory skin disorder affecting 5-20% of children worldwide, while the prevalence in adults varies from 7 to 10%. Patients with AD experience intense pruritus that could lead to sleep disturbance and impaired quality of life. Here, we analyze the pathophysiology of itchiness in AD. We extensively review the histamine-dependent and histamine-independent pruritogens. Several receptors, substance P, secreted molecules, chemokines, and cytokines are involved as mediators in chronic itch. We also, summarize the new emerging antipruritic drugs in atopic dermatitis.
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Affiliation(s)
- Dimitra Koumaki
- Dermatology Department, University Hospital of Heraklion, 71110 Heraklion, Greece
| | - Stamatios Gregoriou
- Department of Dermatology and Venereology, Andreas Sygros Hospital, Medical School of Athens, National and Kapodistrian University of Athens, 16121 Athens, Greece
| | - George Evangelou
- Dermatology Department, University Hospital of Heraklion, 71110 Heraklion, Greece
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16
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Chen O, He Q, Han Q, Furutani K, Gu Y, Olexa M, Ji RR. Mechanisms and treatments of neuropathic itch in a mouse model of lymphoma. J Clin Invest 2023; 133:160807. [PMID: 36520531 PMCID: PMC9927942 DOI: 10.1172/jci160807] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 12/13/2022] [Indexed: 12/23/2022] Open
Abstract
Our understanding of neuropathic itch is limited due to a lack of relevant animal models. Patients with cutaneous T cell lymphoma (CTCL) experience severe itching. Here, we characterize a mouse model of chronic itch with remarkable lymphoma growth, immune cell accumulation, and persistent pruritus. Intradermal CTCL inoculation produced time-dependent changes in nerve innervations in lymphoma-bearing skin. In the early phase (20 days), CTCL caused hyperinnervations in the epidermis. However, chronic itch was associated with loss of epidermal nerve fibers in the late phases (40 and 60 days). CTCL was also characterized by marked nerve innervations in mouse lymphoma. Blockade of C-fibers reduced pruritus at early and late phases, whereas blockade of A-fibers only suppressed late-phase itch. Intrathecal (i.t.) gabapentin injection reduced late-phase, but not early-phase, pruritus. IL-31 was upregulated in mouse lymphoma, whereas its receptor Il31ra was persistently upregulated in Trpv1-expressing sensory neurons in mice with CTCL. Intratumoral anti-IL-31 treatment effectively suppressed CTCL-induced scratching and alloknesis (mechanical itch). Finally, i.t. administration of a TLR4 antagonist attenuated pruritus in early and late phases and in both sexes. Collectively, we have established a mouse model of neuropathic and cancer itch with relevance to human disease. Our findings also suggest distinct mechanisms underlying acute, chronic, and neuropathic itch.
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Affiliation(s)
- Ouyang Chen
- Center for Translational Pain Medicine, Department of Anesthesiology,,Department of Cell Biology, and
| | - Qianru He
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Qingjian Han
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Kenta Furutani
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Yun Gu
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Madelynne Olexa
- Center for Translational Pain Medicine, Department of Anesthesiology
| | - Ru-Rong Ji
- Center for Translational Pain Medicine, Department of Anesthesiology,,Department of Cell Biology, and,Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, USA
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17
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Yang N, Shao H, Deng J, Yang Y, Tang Z, Wu G, Liu Y. Dictamnine ameliorates chronic itch in DNFB-induced atopic dermatitis mice via inhibiting MrgprA3. Biochem Pharmacol 2023; 208:115368. [PMID: 36493846 DOI: 10.1016/j.bcp.2022.115368] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 11/24/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
Chronic itch is the most prominent feature of atopic dermatitis (AD), and antihistamine treatment is often less effective in reducing clinical pruritus severity in AD. Multiple studies have shown that histamine-independent itch pathway is thought to predominate in AD-induced chronic itch. Mas-related G-protein-coupled receptor (Mrgpr) A3+ sensory neurons have been identified as one of the major itch-sensing neuron populations, and transient receptor potential (TRP) channel A1 is the key downstream of MrgprA3-mediated histamine-independent itch. MrgprA3-TRPA1 signal pathway is necessary for the development of chronic itch and may be the potentially promising target of chronic itch in AD. Dictamnine is one of the main quinoline alkaloid components of Cortex Dictamni (a traditional Chinese medicine widely used in clinical treatment of skin diseases). However, the anti-inflammatory and anti-pruritic effect of dictamnine on AD have not been reported. In this study, we used the 2,4-dinitrofluorobenzene (DNFB)-induced AD mouse model to observe the scratching behavior, inflammatory manifestations, and to detect the expression of MrgprA3 and TRPA1 in skin and DRG. The data demonstrated that dictamnine effectively inhibited AD-induced chronic itch, inflammation symptoms, epidermal thickening, inflammatory cell infiltration, and downregulated the expression of MrgprA3 and TRPA1. Furthermore, dictamnine restrained the excitability of MrgprA3+ and TRPA1+ neurons. Molecular docking also indicated that dictamnine has better binding affinity with MrgprA3. These results suggest that dictamnine may inhibit chronic itch caused by AD through the MrgprA3-TRPA1 mediated histamine-independent itch pathway, and may have a potential utility in AD treatment.
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Affiliation(s)
- Niuniu Yang
- Department of Traditional Chinese and Western Medicine, Medical College, Yangzhou University, Yangzhou 225009, China; The Key Laboratory of Syndrome Differentiation and Treatment of Gastric Cancer of the State Administration of Traditional Chinese Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225002, China.
| | - Haifeng Shao
- Department of Traditional Chinese and Western Medicine, Medical College, Yangzhou University, Yangzhou 225009, China; The Key Laboratory of Syndrome Differentiation and Treatment of Gastric Cancer of the State Administration of Traditional Chinese Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225002, China
| | - Jialin Deng
- Department of Traditional Chinese and Western Medicine, Medical College, Yangzhou University, Yangzhou 225009, China; The Key Laboratory of Syndrome Differentiation and Treatment of Gastric Cancer of the State Administration of Traditional Chinese Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225002, China
| | - Yan Yang
- School of Medicine and Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China; Key Laboratory for Chinese Medicine of Prevention and Treatment in Neurological Diseases, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Zongxiang Tang
- School of Medicine and Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing 210023, China; Key Laboratory for Chinese Medicine of Prevention and Treatment in Neurological Diseases, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Guanyi Wu
- College of Basic Medicine, Guangxi University of Chinese Medicine, Nanning 530299, China
| | - Yanqing Liu
- Department of Traditional Chinese and Western Medicine, Medical College, Yangzhou University, Yangzhou 225009, China; The Key Laboratory of Syndrome Differentiation and Treatment of Gastric Cancer of the State Administration of Traditional Chinese Medicine, Yangzhou University, Yangzhou 225009, China; Jiangsu Key Laboratory of Integrated Traditional Chinese and Western Medicine for Prevention and Treatment of Senile Diseases, Yangzhou University, Yangzhou 225002, China
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18
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Shao M, Liu J, Luo H. Colitis aggravated by Mrgprb2 knockout is associated with altered immune response, intestinal barrier function and gut microbiota. Exp Physiol 2023; 108:63-75. [PMID: 36440681 PMCID: PMC10103767 DOI: 10.1113/ep090635] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 10/19/2022] [Indexed: 11/29/2022]
Abstract
NEW FINDINGS What is the central question of this study? What is the role of mas-related G protein-coupled receptor X2 (MRGPRX2/Mrgprb2) in ulcerative colitis in relation to the intestinal flora, intestinal barrier and immune response? What is the main finding and its importance? Knockout of mouse Mrgprb2 aggravates dextran sulfate sodium (DSS)-induced colitis, which is associated with altered gut microbiota and immune response and disruption of the intestinal barrier. MRGPRB2 may have a protective effect on DSS-induced colitis. ABSTRACT Ulcerative colitis (UC) is a chronic immune-related disease, and changes in the intestinal microbiota and damage to the intestinal barrier contribute to its pathogenesis. Mast cells (MCs) are widely distributed in the gastrointestinal tract and are thought to be related to the pathogenesis of UC. Human mas-related G protein-coupled receptor X2 (MRGPRX2) and its mouse homologue, Mrgprb2, are selectively expressed on MCs to recruit immune cells and modulate host defence against microbial infection. To investigate the role of Mrgprb2 in UC in mice, we compared the differences between Mrgprb2 knockout (b2KO) male mice and wild-type (WT) male mice with dextran sulfate sodium (DSS)-induced colitis in the severity of clinical symptoms, inflammatory cell infiltration, degree of intestinal barrier damage and composition of the intestinal flora. The results showed that weight loss, disease activity index score, colon shortening and colonic pathological damage were significantly increased in b2KO mice while MC activation, cytokine and chemokine secretion, and inflammatory cell infiltration were decreased. In addition, the abundance and diversity of the intestinal microbiota were reduced in b2KO mice. B2KO mice also exhibited a reduction of probiotics such as norank_f_Muribaculaceae and Lactobacillus and increase of harmful bacteria like Escherichia-Shigella. Intestinal mucosal barrier damage of b2KO mice was more severe than that of WT mice due to the attenuated expression of mucin-2 and occludin. These results demonstrated that MRGPRB2 may have a protective effect on DSS-induced colitis by altering the intestinal flora, participating in barrier repair and recruiting inflammatory cells to eliminate pathogens.
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Affiliation(s)
- Ming Shao
- Department of GastroenterologyRenmin Hospital of Wuhan UniversityWuhanChina
- Department of GastroenterologyHubei Key Laboratory of Digestive DiseasesWuhanChina
| | - Jingwen Liu
- Department of GastroenterologyRenmin Hospital of Wuhan UniversityWuhanChina
- Department of GastroenterologyHubei Key Laboratory of Digestive DiseasesWuhanChina
| | - Hesheng Luo
- Department of GastroenterologyRenmin Hospital of Wuhan UniversityWuhanChina
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19
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Zhou GK, Xu WJ, Lu Y, Zhou Y, Feng CZ, Zhang JT, Sun SY, Wang RM, Liu T, Wu B. Acid-sensing ion channel 3 is required for agmatine-induced histamine-independent itch in mice. Front Mol Neurosci 2023; 16:1086285. [PMID: 36937045 PMCID: PMC10016355 DOI: 10.3389/fnmol.2023.1086285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Accepted: 02/06/2023] [Indexed: 03/05/2023] Open
Abstract
Introduction Itch is a common symptom of many skin and systemic diseases. Identifying novel endogenous itch mediators and the downstream signaling pathways involved will contribute to the development of new strategies for the treatment of chronic itch. In the present study, we adopted behavioral testing, patch clamp recording and metabonomics analysis to investigate the role of agmatine in itch and the underlying mechanism. Methods Behavioral analysis was used to evaluate the establishing of acute and chronic itch mice model, and to test the effects of different drugs or agents on mice itch behavior. Western blotting analysis was used to test the effect of agmatine on phosphorylation of ERK (p-ERK) expression in the spinal cord. Patch clamp recording was used to determine the effect agmatine on the excitability of DRG neurons and the role of ASIC3. Finally, the metabonomics analysis was performed to detect the concentration of agmatine in the affected skin under atopic dermatitis or psoriasis conditions. Results We fused a mouse model and found that an intradermal injection of agmatine (an endogenous polyamine) into the nape of the neck or cheek induced histamine-independent scratching behavior in a dose-dependent manner. In addition, the ablation of nociceptive C-fibers by resiniferatoxin (RTX) abolished agmatine-induced scratching behavior. However, agmatine-induced itch was not affected by the pharmacological inhibition of either transient receptor potential vanilloid 1 (TRPV1) or transient receptor potential ankyrin 1 (TRPA1); similar results were obtained from TRPV1-/- or TRPA1-/- mice. Furthermore, agmatine-induced itch was significantly suppressed by the administration of acid-sensing ion channel 3 (ASIC3) inhibitors, APETx2 or amiloride. Agmatine also induced the upregulation of p-ERK in the spinal cord; this effect was inhibited by amiloride. Current clamp recording showed that the acute perfusion of agmatine reduced the rheobase and increased the number of evoked action potentials in acute dissociated dorsal root ganglion (DRG) neurons while amiloride reversed agmatine-induced neuronal hyperexcitability. Finally, we identified significantly higher levels of agmatine in the affected skin of a mouse model of atopic dermatitis (AD) when compared to controls, and the scratching behavior of AD mice was significantly attenuated by blocking ASIC3. Discussion Collectively, these results provide evidence that agmatine is a novel mediator of itch and induces itch via the activation of ASIC3. Targeting neuronal ASIC3 signaling may represent a novel strategy for the treatment of itch.
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Affiliation(s)
- Guo-Kun Zhou
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Wen-Jing Xu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Yi Lu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Yan Zhou
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Chen-Zhang Feng
- State Key Laboratory of Neuroscience, Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Institute of Neuroscience, Shanghai, China
| | - Jiang-Tao Zhang
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Shi-Yu Sun
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
| | - Ruo-Meng Wang
- Jiangsu Key Laboratory of Neuropsychiatric Diseases, Institute of Neuroscience, Soochow University, Suzhou, China
| | - Tong Liu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
- College of Life Sciences, Yanan University, Yanan, China
- Suzhou Key Laboratory of Intelligent Medicine and Equipment, Suzhou, China
- *Correspondence: Tong Liu,
| | - Bin Wu
- Institute of Pain Medicine and Special Environmental Medicine, Nantong University, Nantong, Jiangsu, China
- Bin Wu,
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20
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Upregulation of DRG protein TMEM100 facilitates dry-skin-induced pruritus by enhancing TRPA1 channel function. Acta Biochim Biophys Sin (Shanghai) 2022; 55:404-416. [PMID: 36514220 PMCID: PMC10160222 DOI: 10.3724/abbs.2022180] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The dry skin tortures numerous patients with severe itch. The transient receptor potential cation channel V member 1 (TRPV1) and A member 1 (TRPA1) are two essential receptors for peripheral neural coding of itch sensory, mediating histaminergic and nonhistaminergic itch separately. In the dorsal root ganglion, transmembrane protein 100 (TMEM100) is structurally related to both TRPV1 and TRPA1 receptors, but the exact role of TMEM100 in itch sensory coding is still unknown. Here, in this study, we find that TMEM100 + DRG neurons account for the majority of activated neurons in an acetone-ether-water (AEW)-induced dry skin itch model, and some TMEM100 + DRG neurons are colocalized with both TRPA1 and the chloroquine-related Mrgpr itch receptor family. Both the expression and function of TRPA1 channels, but not TRPV1 channels, are upregulated in the AEW model, and specific DRG Tmem100 gene knockdown alleviates AEW-induced itch and rescues the expression and functional changes of TRPA1. Our results strongly suggest that TMEM100 protein in DRG is the main facilitating factor for dry-skin-related chronic itch, and specific suppression of TMEM100 in DRG could be a novel effective treatment strategy for patients who suffer from dry skin-induced itch.
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21
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Abstract
Chronic pruritus is a classic symptom in patients with primary biliary cholangitis. It affects up to two-thirds of patients in the course of the disease. Efficient therapy consists of topical treatment combined with systemic options such as anion exchangers, rifampicin, bezafibrate, μ-opioid receptor antagonists, selective-serotonin receptor uptake inhibitors, and gabapentinoids. Future therapeutic approaches may contain the selective blockade of the enterohepatic cycle by inhibiting the ileal bile acid transporter, the agonism at κ-opioid receptors, and antagonism of the mas-related G protein-coupled receptor X4. As nondrug treatment, ultraviolet B therapy, albumin dialysis, and biliary drainage are available at specialized centers.
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Affiliation(s)
- Miriam M Düll
- Department of Medicine 1, Gastroenterology, Hepatology, Pneumology, Endocrinology, University Hospital Erlangen and Friedrich-Alexander-University Erlangen-Nürnberg, Erlangen, Ulmenweg 18, 91054 Erlangen, Germany
| | - Andreas E Kremer
- Department of Gastroenterology and Hepatology, Universitäts Spital Zürich, Rämistrasse 100, 8091 Zürich, Switzerland.
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22
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Wong LS, Yen YT. Chronic Nodular Prurigo: An Update on the Pathogenesis and Treatment. Int J Mol Sci 2022; 23:ijms232012390. [PMID: 36293248 PMCID: PMC9604302 DOI: 10.3390/ijms232012390] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 11/05/2022] Open
Abstract
Chronic nodular prurigo (CNPG) is a recalcitrant chronic itchy disorder that affects the quality of life. It can be triggered by multiple etiologies, such as atopic dermatitis, diabetes, and chronic renal diseases. The mechanisms of CNPG are complicated and involved the interaction of the cutaneous, immune, and nervous systems. Diverse immune cells, including eosinophils, neutrophils, T cells, macrophages, and mast cells infiltrated the lesional skin of CNPG, which initiated the inflammatory cytokines and pruritogens release. In addition, the interaction between the immune cells and activated peripheral sensory nerve fibers by neurotransmitters caused neuroinflammation in the skin and intractable itch. This itch-scratch vicious cycle of CNPG results in disease exacerbation. CNPG is difficult to treat with traditional therapies. Recently, great advances have been made in the pathophysiology of both inflammation and pruritus transmission in CNPG. In this review, we summarize the updated mechanisms and novel therapies for CNPG.
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Affiliation(s)
- Lai-San Wong
- Department of Dermatology, Kaohsiung Chang Gung Memorial Hospital and Chang Gung University College of Medicine, Kaohsiung 833, Taiwan
| | - Yu-Ta Yen
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan
- Department of Dermatology, Fooyin University Hospital, Pingtung 928, Taiwan
- Correspondence: ; Tel.: +886-8-832-3146
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23
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Mast cell–neuron axis in allergy. Curr Opin Immunol 2022; 77:102213. [DOI: 10.1016/j.coi.2022.102213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 04/11/2022] [Accepted: 04/20/2022] [Indexed: 11/23/2022]
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24
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Lazki-Hagenbach P, Kleeblatt E, Ali H, Sagi-Eisenberg R. Spatiotemporal Patterns of Substance P-Bound MRGPRX2 Reveal a Novel Connection Between Macropinosome Resolution and Secretory Granule Regeneration in Mast Cells. Front Immunol 2022; 13:892239. [PMID: 35837385 PMCID: PMC9273857 DOI: 10.3389/fimmu.2022.892239] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 05/30/2022] [Indexed: 12/02/2022] Open
Abstract
MRGPRX2, the human member of the MAS-related G protein coupled receptors (Mrgprs), serves as the cellular target of human mast cells (MCs) for innate ligands, including neuropeptides and antimicrobial peptides. In addition, MRGPRX2 also functions as the receptor for multiple FDA-approved drugs. As such, MRGPRX2 is a mediator of MC responses in neurogenic inflammation, host defense and pseudoallergy. We analyzed the spatiotemporal patterns of MRGPRX2 following its binding of the neuropeptide substance P (SP). Herein, we show that MRGPRX2 internalizes via both endocytosis and macropinocytosis, followed by its distribution between a perinuclear region and the secretory granules (SGs). Further, we show that MRGPRX2-containing macropinosomes undergo resolution by a mechanism that involves dynamin and LC3, giving rise to the incorporation of both LC3 and MRGPRX2 into the SGs. SP then promotes the acidification of the LC3-associated SGs, presumably by stimulating their fusion with lysosomes. Taken together, our results reveal a unique mode of MRGPRX2 trafficking that complements endocytosis and involves macropinocytosis, autophagic machinery-assisted macropinosome resolution and receptor delivery to the SGs.
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Affiliation(s)
- Pia Lazki-Hagenbach
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Elisabeth Kleeblatt
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Hydar Ali
- Department of Basic and Translational Sciences, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ronit Sagi-Eisenberg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- *Correspondence: Ronit Sagi-Eisenberg,
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25
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Tseng PY, Hoon MA. GPR15L is an epithelial inflammation-derived pruritogen. SCIENCE ADVANCES 2022; 8:eabm7342. [PMID: 35704588 PMCID: PMC9200282 DOI: 10.1126/sciadv.abm7342] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 05/02/2022] [Indexed: 05/09/2023]
Abstract
Itch is an unpleasant sensation that often accompanies chronic dermatological conditions. Although many of the itch receptors and the neural pathways underlying this sensation are known, the identity of endogenous ligands is still not fully appreciated. Using an unbiased bioinformatic approach, we identified GPR15L as a candidate pruritogen whose expression is robustly up-regulated in psoriasis and atopic dermatitis. Although GPR15L was previously shown to be a cognate ligand of the receptor GPR15, expressed in dermal T cells, here we show that it also contributes to pruritogenesis by activating Mas-related G protein-coupled receptors (MRGPRs). GPR15L can selectively stimulate mouse dorsal root ganglion neurons that express Mrgpra3 and evokes intense itch responses. GPR15L causes mast cell degranulation through stimulation of MRGPRX2 and Mrgprb2. Genetic disruption of GPR15L expression attenuates scratch responses in a mouse model of psoriasis. Our study reveals unrecognized features of GRP15L, showing that it is a potent itch-inducing agent.
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Affiliation(s)
- Pang-Yen Tseng
- Molecular Genetics Section, National Institute of Dental and Craniofacial Research/NIH, 35 Convent Drive, Bethesda, MD 20892, USA
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26
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Caldwell A, Grundy L, Harrington AM, Garcia-Caraballo S, Castro J, Bunnett NW, Brierley SM. TGR5 agonists induce peripheral and central hypersensitivity to bladder distension. Sci Rep 2022; 12:9920. [PMID: 35705684 PMCID: PMC9200837 DOI: 10.1038/s41598-022-14195-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 06/02/2022] [Indexed: 11/30/2022] Open
Abstract
The mechanisms underlying chronic bladder conditions such as interstitial cystitis/bladder pain syndrome (IC/BPS) and overactive bladder syndrome (OAB) are incompletely understood. However, targeting specific receptors mediating neuronal sensitivity to specific stimuli is an emerging treatment strategy. Recently, irritant-sensing receptors including the bile acid receptor TGR5, have been identified within the viscera and are thought to play a key role in neuronal hypersensitivity. Here, in mice, we identify mRNA expression of TGR5 (Gpbar1) in all layers of the bladder as well as in the lumbosacral dorsal root ganglia (DRG) and in isolated bladder-innervating DRG neurons. In bladder-innervating DRG neurons Gpbar1 mRNA was 100% co-expressed with Trpv1 and 30% co-expressed with Trpa1. In vitro live-cell calcium imaging of bladder-innervating DRG neurons showed direct activation of a sub-population of bladder-innervating DRG neurons with the synthetic TGR5 agonist CCDC, which was diminished in Trpv1-/- but not Trpa1-/- DRG neurons. CCDC also activated a small percentage of non-neuronal cells. Using an ex vivo mouse bladder afferent recording preparation we show intravesical application of endogenous (5α-pregnan-3β-ol-20-one sulphate, Pg5α) and synthetic (CCDC) TGR5 agonists enhanced afferent mechanosensitivity to bladder distension. Correspondingly, in vivo intravesical administration of CCDC increased the number of spinal dorsal horn neurons that were activated by bladder distension. The enhanced mechanosensitivity induced by CCDC ex vivo and in vivo was absent using Gpbar1-/- mice. Together, these results indicate a role for the TGR5 receptor in mediating bladder afferent hypersensitivity to distension and thus may be important to the symptoms associated with IC/BPS and OAB.
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Affiliation(s)
- Ashlee Caldwell
- Visceral Pain Research Group, College of Medicine and Public Health, Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, South Australia, 5042, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, Level 7, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia, 5000, Australia
- Discipline of Medicine, University of Adelaide, Level 7, SAHMRI, North Terrace, Adelaide, South Australia, 5000, Australia
| | - Luke Grundy
- Visceral Pain Research Group, College of Medicine and Public Health, Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, South Australia, 5042, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, Level 7, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia, 5000, Australia
| | - Andrea M Harrington
- Visceral Pain Research Group, College of Medicine and Public Health, Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, South Australia, 5042, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, Level 7, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia, 5000, Australia
| | - Sonia Garcia-Caraballo
- Visceral Pain Research Group, College of Medicine and Public Health, Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, South Australia, 5042, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, Level 7, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia, 5000, Australia
| | - Joel Castro
- Visceral Pain Research Group, College of Medicine and Public Health, Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, South Australia, 5042, Australia
- Hopwood Centre for Neurobiology, Lifelong Health Theme, Level 7, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia, 5000, Australia
| | - Nigel W Bunnett
- Department of Molecular Pathobiology, Department of Neuroscience and Physiology, Neuroscience Institute, New York University, New York, NY, USA
| | - Stuart M Brierley
- Visceral Pain Research Group, College of Medicine and Public Health, Flinders Health and Medical Research Institute (FHMRI), Flinders University, Bedford Park, South Australia, 5042, Australia.
- Hopwood Centre for Neurobiology, Lifelong Health Theme, Level 7, South Australian Health and Medical Research Institute (SAHMRI), North Terrace, Adelaide, South Australia, 5000, Australia.
- Discipline of Medicine, University of Adelaide, Level 7, SAHMRI, North Terrace, Adelaide, South Australia, 5000, Australia.
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27
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Van Remoortel S, Lambeets L, Timmermans JP. Neuro-immune interactions and the role of Mas-related G protein-coupled receptors in the gastrointestinal tract. Anat Rec (Hoboken) 2022; 306:1131-1139. [PMID: 35694864 DOI: 10.1002/ar.25008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 05/11/2022] [Accepted: 05/20/2022] [Indexed: 11/10/2022]
Abstract
Over the past decade, the research field dealing with the role of a new family of Rhodopsin A-like G protein-coupled receptors, that is, the family of Mas-related G protein-coupled receptors (Mrgprs) has expanded enormously. A plethora of recent studies have provided evidence that Mrgprs are key players in itch and pain, as well as in the initiation and modulation of inflammatory/allergic responses in the skin. Over the years, it has become clear that this role is not limited to the skin, but extends to other mucosal surfaces such as the respiratory tract and the gastrointestinal (GI) tract. In the GI tract, Mrgprs have emerged as novel interoceptive sensory pathways linked to health and disease, and are in close functional association with the gut's immune system. This review aims to 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 GI system.
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Affiliation(s)
- Samuel Van Remoortel
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
| | - Lana Lambeets
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
| | - Jean-Pierre Timmermans
- Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Laboratory of Cell Biology and Histology, University of Antwerp, Antwerp, Belgium
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28
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Spinal ascending pathways for somatosensory information processing. Trends Neurosci 2022; 45:594-607. [PMID: 35701247 DOI: 10.1016/j.tins.2022.05.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2022] [Revised: 04/19/2022] [Accepted: 05/14/2022] [Indexed: 12/27/2022]
Abstract
The somatosensory system processes diverse types of information including mechanical, thermal, and chemical signals. It has an essential role in sensory perception and body movement and, thus, is crucial for organism survival. The neural network for processing somatosensory information comprises multiple key nodes. Spinal projection neurons represent the key node for transmitting somatosensory information from the periphery to the brain. Although the anatomy of spinal ascending pathways has been characterized, the mechanisms underlying somatosensory information processing by spinal ascending pathways are incompletely understood. Recent studies have begun to reveal the diversity of spinal ascending pathways and their functional roles in somatosensory information processing. Here, we review the anatomic, molecular, and functional characteristics of spinal ascending pathways.
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29
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Steinhoff M, Ahmad F, Pandey A, Datsi A, AlHammadi A, Al-Khawaga S, Al-Malki A, Meng J, Alam M, Buddenkotte J. Neuro-immune communication regulating pruritus in atopic dermatitis. J Allergy Clin Immunol 2022; 149:1875-1898. [PMID: 35337846 DOI: 10.1016/j.jaci.2022.03.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 02/13/2022] [Accepted: 03/10/2022] [Indexed: 11/26/2022]
Abstract
Atopic dermatitis (AD) is a common, chronic-relapsing inflammatory skin disease with significant disease burden. Genetic and environmental trigger factors contribute to AD, activating two of our largest organs, the nervous and immune system. Dysregulation of neuro-immune circuits plays a key role in the pathophysiology of AD causing inflammation, pruritus, pain, and barrier dysfunction. Sensory nerves can be activated by environmental or endogenous trigger factors transmitting itch stimuli to the brain. Upon stimulation, sensory nerve endings also release neuromediators into the skin contributing again to inflammation, barrier dysfunction and itch. Additionally, dysfunctional peripheral and central neuronal structures contribute to neuroinflammation, sensitization, nerve elongation, neuropathic itch, thus chronification and therapy-resistance. Consequently, neuro-immune circuits in skin and central nervous system may be targets to treat pruritus in AD. Cytokines, chemokines, proteases, lipids, opioids, ions excite/sensitize sensory nerve endings not only induce itch but further aggravate/perpetuate inflammation, skin barrier disruption, and pruritus. Thus, targeted therapies for neuro-immune circuits as well as pathway inhibitors (e.g., kinase inhibitors) may be beneficial to control pruritus in AD either in systemic and/or topical form. Understanding neuro-immune circuits and neuronal signaling will optimize our approach to control all pathological mechanisms in AD, inflammation, barrier dysfunction and pruritus.
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Affiliation(s)
- Martin Steinhoff
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar; Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Department of Dermatology, Weill Cornell Medicine-Qatar, Doha, Qatar; Qatar University, College of Medicine, Doha, Qatar; Department of Dermatology, Weill Cornell Medicine, New York, USA.
| | - Fareed Ahmad
- Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Atul Pandey
- Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Angeliki Datsi
- Institute for Transplantational Diagnostics and Cell Therapeutics, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Ayda AlHammadi
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar
| | - Sara Al-Khawaga
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar
| | - Aysha Al-Malki
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar
| | - Jianghui Meng
- National Institute for Cellular Biotechnology, Dublin City University, Dublin, Ireland
| | - Majid Alam
- Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
| | - Joerg Buddenkotte
- Department of Dermatology and Venereology, Hamad Medical Corporation, Doha, Qatar; Translational Research Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar; Dermatology Institute, Academic Health System, Hamad Medical Corporation, Doha, Qatar
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30
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Identification of MrgprD expression in mouse enteric neurons. Cell Tissue Res 2022; 388:479-484. [PMID: 35258714 DOI: 10.1007/s00441-022-03608-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Accepted: 02/25/2022] [Indexed: 12/14/2022]
Abstract
Mas-related G protein-coupled receptor D (MrgprD) was first identified in small-diameter sensory neurons of mouse dorsal root ganglion (DRG). The role of MrgprD has been studied in somatosensation, especially in pain and itch response. We recently showed that MrgprD also participated in the modulation of murine intestinal motility. The treatment of MrgprD receptor agonist suppressed the spontaneous contractions in the isolated intestinal rings of mice, indicating the intrinsic expression of MrgprD in the murine gastrointestinal (GI) tract. Although the expression of Mrgprd in GI tract has been previously detected by the way of quantitative real-time PCR, the cell-type-specific expression of MrgprD in GI tract is no yet determined. Herein, we employed Mrgprd-tdTomato reporter mouse line and the whole-mount immunohistochemistry to observe the localization of MrgprD in the smooth muscle layers of ileum and colon. We show that tdTomato-positive cells colocalized with NeuN-immunostaining in the myenteric plexus in the whole-mount preparations of the ileum and the colon. Further immunohistochemistry using the commercially available MrgprD antibody revealed the expression of MrgprD in NeuN-labeled enteric neurons in the myenteric plexus. Our results demonstrate the expression of MrgprD in the enteric neurons in the murine GI tract, highlighting the implications of MrgprD in the physiology and pathophysiology of the GI tract.
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Modulation of itch and pain signals processing in ventrobasal thalamus by thalamic reticular nucleus. iScience 2022; 25:103625. [PMID: 35106466 PMCID: PMC8786640 DOI: 10.1016/j.isci.2021.103625] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 11/16/2021] [Accepted: 12/10/2021] [Indexed: 01/03/2023] Open
Abstract
Thalamic reticular nucleus (TRN) is known to be crucial for dynamically modulating sensory processing. Recently, the functional role of TRN in itch and pain sensation processing has drawn much attention. We found that ventrobasal thalamus (VB) neurons exhibited scratching behavior-related and nociceptive behavior-related neuronal activity changes, and most of VB neurons responsive to pruritic stimulus were also activated by nociceptive stimulus. Inhibition of VB could relieve itch-induced scratching behaviors and pathological pain without affecting basal nociceptive thresholds, and activation of VB could facilitate scratching behaviors. Tracing and electrophysiology recording results showed that VB mainly received inhibitory inputs from ventral TRN. Furthermore, optogenetic activation of TRN-VB projections suppressed scratching behaviors, and ablation of TRN enhanced scratching behaviors. In addition, activation of TRN-VB projections relieved the pathological pain without affecting basal nociceptive thresholds. Thus, our study indicates that TRN modulates itch and pain signals processing via TRN-VB inhibitory projections. VB is involved in both itch and pain signals processing Manipulation of VB or TRN-VB inhibitory projections modulates both itch and pain Enhancing the inhibitory tone might be a strategy for treating itch and pain
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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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Guo CJ, Grabinski NS, Liu Q. Peripheral Mechanisms of Itch. J Invest Dermatol 2021; 142:31-41. [PMID: 34838258 DOI: 10.1016/j.jid.2021.10.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 10/15/2021] [Accepted: 10/26/2021] [Indexed: 12/30/2022]
Abstract
Itch is a universally experienced sensation, and chronic itch can be as diabolically debilitating as pain. Recent advances have not only identified the neuronal itch sensing circuitry, but also have uncovered the intricate interactions between skin and immune cells that work together with neurons to identify itch-inducing irritants. In this review, we will summarize the fundamental mechanisms of acute itch detection in the skin, as well as highlight the recent discoveries relating to this topic.
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Affiliation(s)
- Changxiong J Guo
- Center for the Study of Itch & Sensory Disorders, Department of Anesthesiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Nathaniel S Grabinski
- Center for the Study of Itch & Sensory Disorders, Department of Anesthesiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Qin Liu
- Center for the Study of Itch & Sensory Disorders, Department of Anesthesiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, USA.
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34
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Structure, function and pharmacology of human itch receptor complexes. Nature 2021; 600:164-169. [PMID: 34789875 DOI: 10.1038/s41586-021-04077-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 09/30/2021] [Indexed: 11/08/2022]
Abstract
In the clades of animals that diverged from the bony fish, a group of Mas-related G-protein-coupled receptors (MRGPRs) evolved that have an active role in itch and allergic signals1,2. As an MRGPR, MRGPRX2 is known to sense basic secretagogues (agents that promote secretion) and is involved in itch signals and eliciting pseudoallergic reactions3-6. MRGPRX2 has been targeted by drug development efforts to prevent the side effects induced by certain drugs or to treat allergic diseases. Here we report a set of cryo-electron microscopy structures of the MRGPRX2-Gi1 trimer in complex with polycationic compound 48/80 or with inflammatory peptides. The structures of the MRGPRX2-Gi1 complex exhibited shallow, solvent-exposed ligand-binding pockets. We identified key common structural features of MRGPRX2 and describe a consensus motif for peptidic allergens. Beneath the ligand-binding pocket, the unusual kink formation at transmembrane domain 6 (TM6) and the replacement of the general toggle switch from Trp6.48 to Gly6.48 (superscript annotations as per Ballesteros-Weinstein nomenclature) suggest a distinct activation process. We characterized the interfaces of MRGPRX2 and the Gi trimer, and mapped the residues associated with key single-nucleotide polymorphisms on both the ligand and G-protein interfaces of MRGPRX2. Collectively, our results provide a structural basis for the sensing of cationic allergens by MRGPRX2, potentially facilitating the rational design of therapies to prevent unwanted pseudoallergic reactions.
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35
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Kwiatkowska D, Reich A. Role of Mast Cells in the Pathogenesis of Pruritus in Mastocytosis. Acta Derm Venereol 2021; 101:adv00583. [PMID: 34642766 DOI: 10.2340/actadv.v101.350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Pruritus can be defined as an unpleasant sensation that evokes a desire to scratch and significantly impairs patients' quality of life. Pruritus is widely observed in many dermatoses, including mastocytosis, a rare disease characterized by abnormal accumulation of mast cells, which can involve skin, bone marrow, and other organs. Increasing evidence highlights the role of mast cells in neurogenic inflammation and itching. Mast cells release various pruritogenic mediators, initiating subsequent mutual communication with specific nociceptors on sensory nerve fibres. Among important mediators released by mast cells that induce pruritus, one can distinguish histamine, serotonin, proteases, as well as various cytokines. During neuronal-induced inflammation, mast cells may respond to numerous mediators, including neuropeptides, such as substance P, neurokinin A, calcitonin gene-related peptide, endothelin 1, and nerve growth factor. Currently, treatment of pruritus in mastocytosis is focused on alleviating the effects of mediators secreted by mast cells. However, a deeper understanding of the intricacies of the neurobiology of this disease could help to provide better treatment options for patients.
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Affiliation(s)
| | - Adam Reich
- Department of Dermatology, University of Rzeszow, Ul. Szopena 2, PL-35-055 Rzeszów, Poland.
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36
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Desensitization of TRPV1 Involved in the Antipruritic Effect of Osthole on Histamine-Induced Scratching Behavior in Mice. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:4012812. [PMID: 34691215 PMCID: PMC8528571 DOI: 10.1155/2021/4012812] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/30/2021] [Accepted: 09/23/2021] [Indexed: 11/17/2022]
Abstract
Osthole has been isolated from the fruits of Cnidium monnieri (L.) Cusson, which has been used in Chinese traditional medicine to treat pruritic disorders for a long time. However, the antipruritic mechanism of osthole is not fully understood. In the present study, using calcium imaging, molecular docking, and animal scratching behavior, we analyzed the pharmacological effects of osthole on transient receptor potential vanilloid 1 (TRPV1). The results showed that osthole significantly induced calcium influx in a dose-dependent manner in dorsal root ganglion (DRG) neurons. Osthole-induced calcium influx was inhibited by AMG9810, an antagonist of TRPV1. Osthole and the TRPV1 agonist capsaicin-induced calcium influx were desensitized by pretreatment with osthole. Furthermore, molecular docking results showed that osthole could bind to TRPV1 with a hydrogen bond by anchoring to the amino acid residue ARG557 in the binding pocket of TRPV1. In addition, TRPV1 is a downstream ion channel for the histamine H1 and H4 receptors to transmit itch signals. Osthole attenuated scratching behavior induced by histamine, HTMT (histamine H1 receptor agonist), and VUF8430 (histamine H4 receptor agonist) in mice. These results suggest that osthole inhibition of histamine-dependent itch may be due to the activation and subsequent desensitization of TRPV1 in DRG neurons.
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Xu M, Li J, Zhang Z, Liu L, Wan F, Tang Z, Lan L. Mas-related G protein-coupled receptor D is involved in modulation of murine gastrointestinal motility. Exp Physiol 2021; 106:2502-2516. [PMID: 34647371 DOI: 10.1113/ep089958] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/07/2021] [Indexed: 12/27/2022]
Abstract
NEW FINDINGS What is the central question of this study? The physiological function of Mas-related G protein-coupled receptor D (MrgprD) in gastrointestinal motility is unknown. The aim of this study was to assess the effects of MrgprD and its receptor agonists on murine gastrointestinal motility. What is the main finding and its importance? Mrgprd deficiency improved murine gastrointestinal motility in vivo but had no effects on the spontaneous contractions of murine intestinal rings ex vivo. Systemic administration of the MrgprD ligand, either β-alanine or alamandine, delayed gastrointestinal transit in vivo and attenuated the spontaneous contractions of isolated intestinal rings ex vivo. ABSTRACT Mas-related G protein-coupled receptor D (MrgprD) was first identified in sensory neurons of mouse dorsal root ganglion and has been demonstrated to be involved in sensations of pain and itch. Although expression of MrgprD has recently been found in the gastrointestinal (GI) tract, its physiological role in GI motility is unknown. To address this question, we used Mrgprd knockout (Mrgprd-/- ) mice and MrgprD agonists to examine the effects of Mrgprd gene deletion and MrgprD signalling activation, respectively, on murine intestinal motility, both in vivo and ex vivo. We observed that the deletion of Mrgprd accelerated the transmission of charcoal through the mouse GI tract. But Mrgprd deficiency did not affect the mean amplitudes and frequencies of spontaneous contractions in ileum ex vivo. Colonic motor complexes in the proximal and the distal colon were recorded from wild-type and Mrgprd-/- mice, but their control frequencies were not different. Moreover, in wild-type mice, systemic administration of an MrgprD agonist, either β-alanine or alamandine, delayed GI transit in vivo and suppressed spontaneous contractions in the ileum and colonic motor complexes in the colon ex vivo. Our results suggest that MrgprD and its agonist are involved in the modulation of GI motility in mice.
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Affiliation(s)
- Min Xu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, PR China
| | - Jia Li
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, PR China
| | - Zhudi Zhang
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, PR China
| | - Lin Liu
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, PR China
| | - Fengyi Wan
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, Maryland, USA
| | - Zongxiang Tang
- Key Laboratory of Chinese Medicine for Prevention and Treatment of Neurological Diseases, School of Medicine and Life Sciences, Nanjing University of Chinese Medicine, Nanjing, Jiangsu, PR China
| | - Lei Lan
- Jiangsu Key Laboratory for Molecular and Medical Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing, Jiangsu, PR China
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38
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Wimalasena NK, Milner G, Silva R, Vuong C, Zhang Z, Bautista DM, Woolf CJ. Dissecting the precise nature of itch-evoked scratching. Neuron 2021; 109:3075-3087.e2. [PMID: 34411514 PMCID: PMC8497439 DOI: 10.1016/j.neuron.2021.07.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 06/10/2021] [Accepted: 07/26/2021] [Indexed: 01/17/2023]
Abstract
Itch is a discrete and irritating sensation tightly coupled to a drive to scratch. Acute scratching developed evolutionarily as an adaptive defense against skin irritants, pathogens, or parasites. In contrast, the itch-scratch cycle in chronic itch is harmful, inducing escalating itch and skin damage. Clinically and preclinically, scratching incidence is currently evaluated as a unidimensional motor parameter and believed to reflect itch severity. We propose that scratching, when appreciated as a complex, multidimensional motor behavior, will yield greater insight into the nature of itch and the organization of neural circuits driving repetitive motor patterns. We outline the limitations of standard measurements of scratching in rodent models and present new approaches to observe and quantify itch-evoked scratching. We argue that accurate quantitative measurements of scratching are critical for dissecting the molecular, cellular, and circuit mechanisms underlying itch and for preclinical development of therapeutic interventions for acute and chronic itch disorders.
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Affiliation(s)
- Nivanthika K Wimalasena
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - George Milner
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - Ricardo Silva
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Cliff Vuong
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Zihe Zhang
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - Diana M Bautista
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Hellen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
| | - Clifford J Woolf
- F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA.
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Gurnani P, Miloh T, Chandar J, Landau DA, Hajjar F, Yosipovitch G. Systemic causes of non-dermatologic chronic pruritus in the pediatric population and their management: An unexplored area. Pediatr Dermatol 2021; 38:1051-1060. [PMID: 34515372 DOI: 10.1111/pde.14596] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Chronic pruritus associated with systemic diseases in the pediatric population has been infrequently addressed in the literature. This review focuses on chronic pruritus presenting without cutaneous manifestations. Common systemic etiologies include diseases with hepatic, renal, and hematologic origins. This encompasses several congenital liver disorders, end-stage renal disease (ESRD), and lymphoproliferative disorders such as Hodgkin's lymphoma. In this paper, an expert panel describes the clinical characteristics, pathophysiology, and therapeutic treatment ladders for chronic pruritus associated with the aforementioned systemic etiologies. Novel therapies are also reviewed. Our aim is to shed light on this unexplored area of pediatric dermatology and instigate further research.
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Affiliation(s)
- Pooja Gurnani
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery & Miami Itch Center, University of Miami, Miller School of Medicine, Miami, FL, USA.,Florida International University, Herbert Wertheim College of Medicine, Miami, FL, USA
| | - Tamir Miloh
- Pediatric Transplant Hepatology, Miami Transplant Institute, Jackson Health System, Miami, FL, USA
| | - Jayanthi Chandar
- Pediatric Kidney Transplantation, Miami Transplant Institute, Jackson Health System, Miami, FL, USA
| | | | - Fouad Hajjar
- AdventHealth For Children Pediatric Oncology and Hematology, Orlando, FL, USA
| | - Gil Yosipovitch
- Dr. Phillip Frost Department of Dermatology and Cutaneous Surgery & Miami Itch Center, University of Miami, Miller School of Medicine, Miami, FL, USA
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Misery L, Brenaut E, Pierre O, Le Garrec R, Gouin O, Lebonvallet N, Abasq-Thomas C, Talagas M, Le Gall-Ianotto C, Besner-Morin C, Fluhr JW, Leven C. Chronic itch: emerging treatments following new research concepts. Br J Pharmacol 2021; 178:4775-4791. [PMID: 34463358 DOI: 10.1111/bph.15672] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 08/20/2021] [Accepted: 08/24/2021] [Indexed: 11/29/2022] Open
Abstract
Until recently, itch pathophysiology was poorly understood and treatments were poorly effective in relieving itch. Current progress in our knowledge of the itch processing, the numerous mediators and receptors involved has led to a large variety of possible therapeutic pathways. Currently, inhibitors of IL-31, IL-4/13, NK1 receptors, opioids and cannabinoids, JAK, PDE4 or TRP are the main compounds involved in clinical trials. However, many new targets, such as Mas-related GPCRs and unexpected new pathways need to be also explored.
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Affiliation(s)
- Laurent Misery
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | - Emilie Brenaut
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | | | | | - Olivier Gouin
- LIEN, Univ Brest, Brest, France.,INSERM UMR 1163, Laboratory of Genetic Skin Diseases, Imagine Institute, Paris, France.,University of Paris, Paris, France
| | | | - Claire Abasq-Thomas
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | - Matthieu Talagas
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France
| | | | - Catherine Besner-Morin
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France.,Division of Dermatology, McGill University Health Centre, Montreal General Hospital, Montreal, Quebec, Canada
| | - Joachim W Fluhr
- LIEN, Univ Brest, Brest, France.,Department of Dermatology, University Hospital of Brest, Brest, France.,Department of Dermatology, Charité Universitätsmedizin, Berlin, Germany
| | - Cyril Leven
- LIEN, Univ Brest, Brest, France.,EA3878, FCRIN INNOVTE, groupe d'étude thrombose Bretagne Occidentale, Brest, France.,Department of Biochemistry and Pharmaco-Toxicology, University Hospital of Brest, Brest, France
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41
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Galli SJ, Gaudenzio N, Tsai M. Mast Cells in Inflammation and Disease: Recent Progress and Ongoing Concerns. Annu Rev Immunol 2021; 38:49-77. [PMID: 32340580 DOI: 10.1146/annurev-immunol-071719-094903] [Citation(s) in RCA: 168] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Mast cells have existed long before the development of adaptive immunity, although they have been given different names. Thus, in the marine urochordate Styela plicata, they have been designated as test cells. However, based on their morphological characteristics (including prominent cytoplasmic granules) and mediator content (including heparin, histamine, and neutral proteases), test cells are thought to represent members of the lineage known in vertebrates as mast cells. So this lineage presumably had important functions that preceded the development of antibodies, including IgE. Yet mast cells are best known, in humans, as key sources of mediators responsible for acute allergic reactions, notably including anaphylaxis, a severe and potentially fatal IgE-dependent immediate hypersensitivity reaction to apparently harmless antigens, including many found in foods and medicines. In this review, we briefly describe the origins of tissue mast cells and outline evidence that these cells can have beneficial as well as detrimental functions, both innately and as participants in adaptive immune responses. We also discuss aspects of mast cell heterogeneity and comment on how the plasticity of this lineage may provide insight into its roles in health and disease. Finally, we consider some currently open questions that are yet unresolved.
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Affiliation(s)
- Stephen J Galli
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, USA; , .,Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California 94305, USA.,Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, California 94305, USA
| | - Nicolas Gaudenzio
- Unité de Différenciation Epithéliale et Autoimmunité Rhumatoïde (UDEAR), INSERM UMR 1056, Université de Toulouse, 31 059 Toulouse CEDEX 9, France;
| | - Mindy Tsai
- Department of Pathology, Stanford University School of Medicine, Stanford, California 94305, USA; , .,Sean N. Parker Center for Allergy and Asthma Research, Stanford University School of Medicine, California 94305, USA
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42
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The Implications of Pruritogens in the Pathogenesis of Atopic Dermatitis. Int J Mol Sci 2021; 22:ijms22137227. [PMID: 34281281 PMCID: PMC8269281 DOI: 10.3390/ijms22137227] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/29/2021] [Accepted: 07/01/2021] [Indexed: 01/17/2023] Open
Abstract
Atopic dermatitis (AD) is a prototypic inflammatory disease that presents with intense itching. The pathophysiology of AD is multifactorial, involving environmental factors, genetic susceptibility, skin barrier function, and immune responses. A recent understanding of pruritus transmission provides more information about the role of pruritogens in the pathogenesis of AD. There is evidence that pruritogens are not only responsible for eliciting pruritus, but also interact with immune cells and act as inflammatory mediators, which exacerbate the severity of AD. In this review, we discuss the interaction between pruritogens and inflammatory molecules and summarize the targeted therapies for AD.
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Mwirigi J, Kume M, Hassler SN, Ahmad A, Ray PR, Jiang C, Chamessian A, Mseeh N, Ludwig BP, Rivera BD, Nieman MT, Van de Ven T, Ji RR, Dussor G, Boitano S, Vagner J, Price TJ. A Role for Protease Activated Receptor Type 3 (PAR3) in Nociception Demonstrated Through Development of a Novel Peptide Agonist. THE JOURNAL OF PAIN 2021; 22:692-706. [PMID: 33429107 PMCID: PMC8197731 DOI: 10.1016/j.jpain.2020.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2020] [Revised: 12/02/2020] [Accepted: 12/20/2020] [Indexed: 02/07/2023]
Abstract
The protease activated receptor (PAR) family is a group of G-protein coupled receptors (GPCRs) activated by proteolytic cleavage of the extracellular domain. PARs are expressed in a variety of cell types with crucial roles in homeostasis, immune responses, inflammation, and pain. PAR3 is the least researched of the four PARs, with little known about its expression and function. We sought to better understand its potential function in the peripheral sensory nervous system. Mouse single-cell RNA sequencing data demonstrates that PAR3 is widely expressed in dorsal root ganglion (DRG) neurons. Co-expression of PAR3 mRNA with other PARs was identified in various DRG neuron subpopulations, consistent with its proposed role as a coreceptor of other PARs. We developed a lipid tethered PAR3 agonist, C660, that selectively activates PAR3 by eliciting a Ca2+ response in DRG and trigeminal neurons. In vivo, C660 induces mechanical hypersensitivity and facial grimacing in WT but not PAR3-/- mice. We characterized other nociceptive phenotypes in PAR3-/- mice and found a loss of hyperalgesic priming in response to IL-6, carrageenan, and a PAR2 agonist, suggesting that PAR3 contributes to long-lasting nociceptor plasticity in some contexts. To examine the potential role of PAR3 in regulating the activity of other PARs in sensory neurons, we administered PAR1, PAR2, and PAR4 agonists and assessed mechanical and affective pain behaviors in WT and PAR3-/- mice. We observed that the nociceptive effects of PAR1 agonists were potentiated in the absence of PAR3. Our findings suggest a complex role of PAR3 in the physiology and plasticity of nociceptors. PERSPECTIVE: We evaluated the role of PAR3, a G-protein coupled receptor, in nociception by developing a selective peptide agonist. Our findings suggest that PAR3 contributes to nociception in various contexts and plays a role in modulating the activity of other PARs.
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Affiliation(s)
- Juliet Mwirigi
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas
| | - Moeno Kume
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas
| | - Shayne N Hassler
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas
| | - Ayesha Ahmad
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas
| | - Pradipta R Ray
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas
| | - Changyu Jiang
- Duke University School of Medicine, Department of Anesthesiology, Pharmacology, and Cancer Biology, Durham, North Carolina
| | - Alexander Chamessian
- Duke University School of Medicine, Department of Anesthesiology, Pharmacology, and Cancer Biology, Durham, North Carolina
| | - Nakleh Mseeh
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas
| | - Breya P Ludwig
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas
| | - Benjamin D Rivera
- Department of Physiology, University of Arizona, Asthma and Airway Disease Research Center, Tucson, Arizona
| | - Marvin T Nieman
- Case Western Reserve University School of Medicine, Department of Pharmacology, Cleveland, Ohio
| | - Thomas Van de Ven
- Duke University School of Medicine, Department of Anesthesiology, Pharmacology, and Cancer Biology, Durham, North Carolina
| | - Ru-Rong Ji
- Duke University School of Medicine, Department of Anesthesiology, Pharmacology, and Cancer Biology, Durham, North Carolina
| | - Gregory Dussor
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas
| | - Scott Boitano
- Department of Physiology, University of Arizona, Asthma and Airway Disease Research Center, Tucson, Arizona
| | - Josef Vagner
- University of Arizona, Bio5 Research Institute, Tucson, Arizona
| | - Theodore J Price
- University of Texas at Dallas, School of Behavioral and Brain Sciences and Center for Advanced Pain Studies, Richardson, Texas.
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Substance P Serves as a Balanced Agonist for MRGPRX2 and a Single Tyrosine Residue Is Required for β-Arrestin Recruitment and Receptor Internalization. Int J Mol Sci 2021; 22:ijms22105318. [PMID: 34070125 PMCID: PMC8158387 DOI: 10.3390/ijms22105318] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/14/2021] [Accepted: 05/15/2021] [Indexed: 12/13/2022] Open
Abstract
The neuropeptide substance P (SP) mediates neurogenic inflammation and pain and contributes to atopic dermatitis in mice through the activation of mast cells (MCs) via Mas-related G protein-coupled receptor (GPCR)-B2 (MrgprB2, human ortholog MRGPRX2). In addition to G proteins, certain MRGPRX2 agonists activate an additional signaling pathway that involves the recruitment of β-arrestins, which contributes to receptor internalization and desensitization (balanced agonists). We found that SP caused β-arrestin recruitment, MRGPRX2 internalization, and desensitization. These responses were independent of G proteins, indicating that SP serves as a balanced agonist for MRGPRX2. A tyrosine residue in the highly conserved NPxxY motif contributes to the activation and internalization of many GPCRs. We have previously shown that Tyr279 of MRGPRX2 is essential for G protein-mediated signaling and degranulation. To assess its role in β-arrestin-mediated MRGPRX2 regulation, we replaced Tyr279 in the NPxxY motif of MRGPRX2 with Ala (Y279A). Surprisingly, we found that, unlike the wild-type receptor, Y279A mutant of MRGPRX2 was resistant to SP-induced β-arrestin recruitment and internalization. This study reveals the novel findings that activation of MRGPRX2 by SP is regulated by β-arrestins and that a highly conserved tyrosine residue within MRGPRX2’s NPxxY motif contributes to both G protein- and β-arrestin-mediated responses.
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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.
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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
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Activation of MrgprA3 and MrgprC11 on Bladder-Innervating Afferents Induces Peripheral and Central Hypersensitivity to Bladder Distension. J Neurosci 2021; 41:3900-3916. [PMID: 33727332 DOI: 10.1523/jneurosci.0033-21.2021] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Revised: 02/28/2021] [Accepted: 03/06/2021] [Indexed: 12/16/2022] Open
Abstract
Understanding the sensory mechanisms innervating the bladder is paramount to developing efficacious treatments for chronic bladder hypersensitivity conditions. The contribution of Mas-gene-related G protein-coupled receptors (Mrgpr) to bladder signaling is currently unknown. Using male and female mice, we show with single-cell RT-PCR that subpopulations of DRG neurons innervating the mouse bladder express MrgprA3 (14%) and MrgprC11 (38%), either individually or in combination, with high levels of coexpression with Trpv1 (81%-89%). Calcium imaging studies demonstrated MrgprA3 and MrgprC11 agonists (chloroquine, BAM8-22, and neuropeptide FF) activated subpopulations of bladder-innervating DRG neurons, showing functional evidence of coexpression between MrgprA3, MrgprC11, and TRPV1. In ex vivo bladder-nerve preparations, chloroquine, BAM8-22, and neuropeptide FF all evoked mechanical hypersensitivity in subpopulations (20%-41%) of bladder afferents. These effects were absent in recordings from Mrgpr-clusterΔ-/- mice. In vitro whole-cell patch-clamp recordings showed that application of an MrgprA3/C11 agonist mixture induced neuronal hyperexcitability in 44% of bladder-innervating DRG neurons. Finally, in vivo instillation of an MrgprA3/C11 agonist mixture into the bladder of WT mice induced a significant activation of dorsal horn neurons within the lumbosacral spinal cord, as quantified by pERK immunoreactivity. This MrgprA3/C11 agonist-induced activation was particularly apparent within the superficial dorsal horn and the sacral parasympathetic nuclei of WT, but not Mrgpr-clusterΔ-/- mice. This study demonstrates, for the first time, functional expression of MrgprA3 and MrgprC11 in bladder afferents. Activation of these receptors triggers hypersensitivity to distension, a critically valuable factor for therapeutic target development.SIGNIFICANCE STATEMENT Determining how bladder afferents become sensitized is the first step in finding effective treatments for common urological disorders such as overactive bladder and interstitial cystitis/bladder pain syndrome. Here we show that two of the key receptors, MrgprA3 and MrgprC11, that mediate itch from the skin are also expressed on afferents innervating the bladder. Activation of these receptors results in sensitization of bladder afferents, resulting in sensory signals being sent into the spinal cord that prematurely indicate bladder fullness. Targeting bladder afferents expressing MrgprA3 or MrgprC11 and preventing their sensitization may provide a novel approach for treating overactive bladder and interstitial cystitis/bladder pain syndrome.
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Jean EE, Good O, Rico JMI, Rossi HL, Herbert DR. Neuroimmune regulatory networks of the airway mucosa in allergic inflammatory disease. J Leukoc Biol 2021; 111:209-221. [PMID: 33857344 PMCID: PMC8674821 DOI: 10.1002/jlb.3ru0121-023r] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 03/16/2021] [Accepted: 03/21/2021] [Indexed: 12/11/2022] Open
Abstract
Communication between the nervous and immune systems serves a key role in host‐protective immunity at mucosal barrier sites including the respiratory tract. In these tissues, neuroimmune interactions operate in bidirectional circuits that can sense and respond to mechanical, chemical, and biologic stimuli. Allergen‐ or helminth‐induced products can produce airway inflammation by direct action on nociceptive afferents and adjacent tissues. The activity of nociceptive afferents can regulate innate and adaptive immune responses via neuropeptides and neurotransmitter signaling. This review will summarize recent work investigating the role of neuropeptides CGRP, VIP, neuromedins, substance P, and neurotransmitters dopamine and the B2‐adrenoceptor agonists epinepherine/norepinepherine, each of which influence type 2 immunity by instructing mast cell, innate lymphoid cell type 2, dendritic cell, and T cell responses, both in the airway and the draining lymph node. Afferents in the airway also contain receptors for alarmins and cytokines, allowing their activity to be modulated by immune cell secreted products, particularly those secreted by mast cells. Taken together, we propose that further investigation of how immunoregulatory neuropeptides shape respiratory inflammation in experimental systems may reveal novel therapeutic targets for addressing the increasing prevalence of chronic airway disease in humans.
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Affiliation(s)
- E Evonne Jean
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Olivia Good
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Juan M Inclan Rico
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - Heather L Rossi
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
| | - De'Broski R Herbert
- Department of Pathobiology, University of Pennsylvania School of Veterinary Medicine, Philadelphia, Pennsylvania, USA
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Abstract
Interactions between the nervous system and immune system are central regulators of chronic itch, a key feature of pathologies like atopic dermatitis and allergic contact dermatitis. Cysteinyl leukotrienes (LTC4, LTD4, and LTE4) are eicosanoid lipids known for mediating inflammation, bronchoconstriction, and vascular leakage. We demonstrate here that CysLTs are potent itch inducers and that this effect depends on the specific coupling of LTC4 with its receptor CysLT2R, which is expressed in a population of peripheral sensory neurons in the mouse and in human. We show that the LTC4/CysLT2R pathway contributes to a model of chronic itch, suggesting that CysLT2R could be a new therapeutic target for intractable chronic itch. Acute and chronic itch are burdensome manifestations of skin pathologies including allergic skin diseases and atopic dermatitis, but the underlying molecular mechanisms are not well understood. Cysteinyl leukotrienes (CysLTs), comprising LTC4, LTD4, and LTE4, are produced by immune cells during type 2 inflammation. Here, we uncover a role for LTC4 and its signaling through the CysLT receptor 2 (CysLT2R) in itch. Cysltr2 transcript is highly expressed in dorsal root ganglia (DRG) neurons linked to itch in mice. We also detected CYSLTR2 in a broad population of human DRG neurons. Injection of leukotriene C4 (LTC4) or its nonhydrolyzable form NMLTC4, but neither LTD4 nor LTE4, induced dose-dependent itch but not pain behaviors in mice. LTC4-mediated itch differed in bout duration and kinetics from pruritogens histamine, compound 48/80, and chloroquine. NMLTC4-induced itch was abrogated in mice deficient for Cysltr2 or when deficiency was restricted to radioresistant cells. Itch was unaffected in mice deficient for Cysltr1, Trpv1, or mast cells (WSh mice). CysLT2R played a role in itch in the MC903 mouse model of chronic itch and dermatitis, but not in models of dry skin or compound 48/80- or Alternaria-induced itch. In MC903-treated mice, CysLT levels increased in skin over time, and Cysltr2−/− mice showed decreased itch in the chronic phase of inflammation. Collectively, our study reveals that LTC4 acts through CysLT2R as its physiological receptor to induce itch, and CysLT2R contributes to itch in a model of dermatitis. Therefore, targeting CysLT signaling may be a promising approach to treat inflammatory itch.
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Single cell transcriptomics of primate sensory neurons identifies cell types associated with chronic pain. Nat Commun 2021; 12:1510. [PMID: 33686078 PMCID: PMC7940623 DOI: 10.1038/s41467-021-21725-z] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 02/08/2021] [Indexed: 01/24/2023] Open
Abstract
Distinct types of dorsal root ganglion sensory neurons may have unique contributions to chronic pain. Identification of primate sensory neuron types is critical for understanding the cellular origin and heritability of chronic pain. However, molecular insights into the primate sensory neurons are missing. Here we classify non-human primate dorsal root ganglion sensory neurons based on their transcriptome and map human pain heritability to neuronal types. First, we identified cell correlates between two major datasets for mouse sensory neuron types. Machine learning exposes an overall cross-species conservation of somatosensory neurons between primate and mouse, although with differences at individual gene level, highlighting the importance of primate data for clinical translation. We map genomic loci associated with chronic pain in human onto primate sensory neuron types to identify the cellular origin of chronic pain. Genome-wide associations for chronic pain converge on two different neuronal types distributed between pain disorders that display different genetic susceptibilities, suggesting both unique and shared mechanisms between different pain conditions. The contribution of distinct types of dorsal root ganglion neurons to chronic pain is unclear. Here, the authors molecularly profile non-human primate sensory neurons and show that genome-wide associations converge on two neuronal types with different genetic susceptibilities for chronic pain.
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A group of cationic amphiphilic drugs activates MRGPRX2 and induces scratching behavior in mice. J Allergy Clin Immunol 2021; 148:506-522.e8. [PMID: 33617860 DOI: 10.1016/j.jaci.2020.12.655] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 11/10/2020] [Accepted: 12/28/2020] [Indexed: 12/14/2022]
Abstract
BACKGROUND Mas gene-related G protein-coupled receptors (MRGPRs) are a G protein-coupled receptor family responsive to various exogenous and endogenous agonists, playing a fundamental role in pain and itch sensation. The primate-specific family member MRGPRX2 and its murine orthologue MRGPRB2 are expressed by mast cells mediating IgE-independent signaling and pseudoallergic drug reactions. OBJECTIVES Our aim was to increase knowledge about the function and regulation of MRGPRX2/MRGPRB2, which is of major importance in prevention of drug hypersensitivity reactions and drug-induced pruritus. METHODS To identify novel MRGPR (ant)agonists, we screened a library of pharmacologically active compounds by utilizing a high-throughput calcium mobilization assay. The identified hit compounds were analyzed for their pseudoallergic and pruritogenic effects in mice and human. RESULTS We found a class of commonly used drugs activating MRGPRX2 that, to a large extent, consists of antidepressants, antiallergic drugs, and antipsychotics. Three-dimensional pharmacophore modeling revealed structural similarities of the identified agonists, classifying them as cationic amphiphilic drugs. Mast cell activation was investigated by using the 3 representatively selected antidepressants clomipramine, paroxetine, and desipramine. Indeed, we were able to show a concentration-dependent activation and MRGPRX2-dependent degranulation of the human mast cell line LAD2 (Laboratory of Allergic Diseases-2). Furthermore, clomipramine, paroxetine, and desipramine were able to induce degranulation of human skin and murine peritoneal mast cells. These substances elicited dose-dependent scratching behavior following intradermal injection into C57BL/6 mice but less so in MRGPRB2-mutant mice, as well as wheal-and-flare reactions following intradermal injections in humans. CONCLUSION Our results contribute to the characterization of structure-activity relationships and functionality of MRGPRX2 ligands and facilitate prediction of adverse reactions such as drug-induced pruritus to prevent severe drug hypersensitivity reactions.
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