1
|
Hawker P, Zhang L, Liu L. Mas-related G protein-coupled receptors in gastrointestinal dysfunction and inflammatory bowel disease: A review. Br J Pharmacol 2023. [PMID: 36787888 DOI: 10.1111/bph.16059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [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.
Collapse
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
| |
Collapse
|
2
|
Dong X, Limjunyawong N, Sypek EI, Wang G, Ortines RV, Youn C, Alphonse MP, Dikeman D, Wang Y, Lay M, Kothari R, Vasavda C, Pundir P, Goff L, Miller LS, Lu W, Garza LA, Kim BS, Archer NK, Dong X. Keratinocyte-derived defensins activate neutrophil-specific receptors Mrgpra2a/b to prevent skin dysbiosis and bacterial infection. Immunity 2022; 55:1645-1662.e7. [PMID: 35882236 PMCID: PMC9474599 DOI: 10.1016/j.immuni.2022.06.021] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 04/19/2022] [Accepted: 06/24/2022] [Indexed: 11/20/2022]
Abstract
Healthy skin maintains a diverse microbiome and a potent immune system to fight off infections. Here, we discovered that the epithelial-cell-derived antimicrobial peptides defensins activated orphan G-protein-coupled receptors (GPCRs) Mrgpra2a/b on neutrophils. This signaling axis was required for effective neutrophil-mediated skin immunity and microbiome homeostasis. We generated mutant mouse lines lacking the entire Defensin (Def) gene cluster in keratinocytes or Mrgpra2a/b. Def and Mrgpra2 mutant animals both exhibited skin dysbiosis, with reduced microbial diversity and expansion of Staphylococcus species. Defensins and Mrgpra2 were critical for combating S. aureus infections and the formation of neutrophil abscesses, a hallmark of antibacterial immunity. Activation of Mrgpra2 by defensin triggered neutrophil release of IL-1β and CXCL2 which are vital for proper amplification and propagation of the antibacterial immune response. This study demonstrated the importance of epithelial-neutrophil signaling via the defensin-Mrgpra2 axis in maintaining healthy skin ecology and promoting antibacterial host defense.
Collapse
Affiliation(s)
- Xintong 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
| | - Nathachit Limjunyawong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Elizabeth I Sypek
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Gaofeng Wang
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Roger V Ortines
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Christine Youn
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Martin P Alphonse
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dustin Dikeman
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yu Wang
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mark Lay
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ruchita Kothari
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Chirag Vasavda
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Priyanka Pundir
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Loyal Goff
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Lloyd S Miller
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Wuyuan Lu
- Department of Biochemistry and Molecular Biology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Luis A Garza
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Brian S Kim
- Kimberly and Eric J. Waldman Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Nathan K Archer
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| | - 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; Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
| |
Collapse
|
3
|
Qi R, Kang Y, Li X, Zhang X, Han Y, Cai R, Gao Y, Qi Y. Forsythiasides-Rich Extract From Forsythiae Fructus Inhibits Mast Cell Degranulation by Enhancing Mitochondrial Ca 2+ Uptake. Front Pharmacol 2021; 12:696729. [PMID: 34194333 PMCID: PMC8237228 DOI: 10.3389/fphar.2021.696729] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2021] [Accepted: 06/02/2021] [Indexed: 11/13/2022] Open
Abstract
Mast cells (MCs) activated via IgE/FcεRI or MAS-related G protein coupled receptor (Mrgpr)-mediated pathway can release granules that play prominent roles in hypersensitivity reactions. Forsythiae Fructus, a well-known traditional Chinese medicine, has been clinically used for allergic diseases. Although previous studies indicated that Forsythiae Fructus extract inhibited compound 48/80-induced histamine release from MCs, its effect on IgE-dependent MC degranulation and possible underlying mechanisms remain to be explored. Herein, we prepared the forsythiasides-rich extract (FRE) and investigated its action on MC degranulation and explored its underlying mechanism. Our data showed that FRE could dampen IgE/FcεRI- and Mrgpr-mediated MC degranulation in vitro and in vivo. Mechanism study indicated that FRE decreased cytosolic Ca2+ (Ca2+[c]) level rapidly and reversibly. Moreover, FRE decreased Ca2+[c] of MCs independent of plasma membrane Ca2+-ATPase (PMCA), sarco/endoplasmic Ca2+-ATPase (SERCA) and Na+/Ca2+ exchanger (NCX). While, along with Ca2+[c] decrease, the increase of mitochondrial Ca2+ (Ca2+[m]) occurred simultaneously in FRE-treated RBL-2H3 cells. In the isolated mitochondria, FRE also promoted the subcellular organelle to uptake more extramitochondrial Ca2+. In conclusion, by increasing Ca2+[m] uptake, FRE decreases Ca2+[c] level to suppress MC degranulation. Our findings may provide theoretical support for the clinical application of Forsythiae Fructus on allergy and other MC-involved diseases.
Collapse
Affiliation(s)
- Ruijuan Qi
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yuan Kang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Ximeng Li
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Xiaoyu Zhang
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yixin Han
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Runlan Cai
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yuan Gao
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| | - Yun Qi
- Institute of Medicinal Plant Development, Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, China
| |
Collapse
|
4
|
Abstract
Owing to their functional diversity, the Mas-related G-protein-coupled receptor (Mrgpr) family has a role in both itch and pain modulation. While primarily linked to pruritis, Mrgprs were originally characterized in small-diameter nociceptive neurons of dorsal root ganglia (DRG) and trigeminal ganglia. This review will focus on the role Mrgpr's have in pain physiology, discussing recent discoveries as well as how Mrgpr's may provide a new target for the treatment of pathological pain.
Collapse
Affiliation(s)
- Dustin P Green
- Department of Neuroscience, Cell Biology, & Anatomy, University of Texas Medical Branch, Galveston, TX, USA
| |
Collapse
|
5
|
Jurcakova D, Ru F, Undem BJ. Allergen-induced histaminergic and non-histaminergic activation of itch C-fiber nerve terminals in mouse skin. Neuroscience 2019; 410:55-58. [PMID: 31047975 DOI: 10.1016/j.neuroscience.2019.04.039] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 03/29/2019] [Accepted: 04/22/2019] [Indexed: 11/16/2022]
Abstract
Acute cutaneous exposure to allergen often leads to itch, but seldom pain. The effect of mast cell activation on cutaneous C-fibers was studied using innervated isolated mouse skin preparation that allows for intra-arterial delivery of chemicals to the nerve terminals in the skin. Allergen (ovalbumin) injection into the isolated skin of actively sensitized mice strongly stimulated chloroquine (CQ)-sensitive C-fibers (also referred to as "itch" nerves); on the other hand, CQ-insensitive C-fibers were activated only modestly, if at all. The histamine H1 receptor antagonist pyrilamine abolished itch C-fibers response to histamine, but failed to significantly reduce the response to ovalbumin. Ovalbumin also strongly activated itch C-fibers in skin isolated from Mrgpr-cluster Δ-/- mice. When pyrilamine was studied in the Mrgpr-cluster Δ-/- mice thereby eliminating the influence of both histamine H1 and Mrgpr receptors (MrgprA3 and C11 are selectively expressed by itch nerves), the ovalbumin response was very nearly eliminated. The data indicate that the acute activation of itch C-fibers in mouse skin is largely secondary to the combined effect of activation of histamine H1 and Mrpgr receptors.
Collapse
Affiliation(s)
- Danica Jurcakova
- Johns Hopkins School of Medicine, Baltimore, MD, USA; Department of Pathophysiology, Jessenius Faculty of Medicine in Martin, Comenius University in Bratislava, Martin, Slovakia
| | - Fei Ru
- Johns Hopkins School of Medicine, Baltimore, MD, USA.
| | | |
Collapse
|
6
|
Meixiong J, Anderson M, Limjunyawong N, Sabbagh MF, Hu E, Mack MR, Oetjen LK, Wang F, Kim BS, Dong X. Activation of Mast-Cell-Expressed Mas-Related G-Protein-Coupled Receptors Drives Non-histaminergic Itch. Immunity 2019; 50:1163-1171.e5. [PMID: 31027996 DOI: 10.1016/j.immuni.2019.03.013] [Citation(s) in RCA: 196] [Impact Index Per Article: 39.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/24/2018] [Accepted: 03/14/2019] [Indexed: 11/28/2022]
Abstract
Classical itch studies have focused on immunoglobulin E (IgE)-mediated mast cell activation and histamine release. Recently, members of the Mas-related G-protein-coupled receptor (Mrgpr) family have been identified as mast cell receptors, but their role in itch is unclear. Here, we report that mast cell activation via Mrgprb2 evoked non-histaminergic itch in mice independently of the IgE-Fc epsilon RI (FcεRI)-histamine axis. Compared with IgE-FcεRI stimulation, Mrgprb2 activation of mast cells was distinct in both released substances (histamine, serotonin, and tryptase) and the pattern of activated itch-sensory neurons. Mrgprb2 deficiency decreased itch in multiple preclinical models of allergic contact dermatitis (ACD), a pruritic inflammatory skin disorder, and both mast cell number and PAMP1-20 concentrations (agonist of the human Mrgprb2 homolog, MRGPRX2) were increased in human ACD skin. These findings suggest that this pathway may represent a therapeutic target for treating ACD and mast-cell-associated itch disorders in which antihistamines are ineffective.
Collapse
Affiliation(s)
- James Meixiong
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michael Anderson
- 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
| | - Mark F Sabbagh
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Eric Hu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Madison R Mack
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Landon K Oetjen
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Fang Wang
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA
| | - Brian S Kim
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO 63110, USA; Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Anesthesiology, Washington University School of Medicine, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, MO 63110, 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.
| |
Collapse
|
7
|
Yamada K, Sato H, Sakamaki K, Kamada M, Okuno Y, Fukuishi N, Furuta K, Tanaka S. Suppression of IgE-Independent Degranulation of Murine Connective Tissue-Type Mast Cells by Dexamethasone. Cells 2019; 8:cells8020112. [PMID: 30717296 PMCID: PMC6406397 DOI: 10.3390/cells8020112] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 01/28/2019] [Accepted: 01/31/2019] [Indexed: 12/16/2022] Open
Abstract
Steroidal anti-inflammatory drugs are widely used for the treatment of chronic cutaneous inflammation, such as atopic dermatitis, although it remains unknown how they modulate cutaneous mast cell functions. We investigated the effects of prolonged treatment with a synthetic glucocorticoid, dexamethasone, on murine connective tissue-type mast cells using in vitro and in vivo models. Our connective tissue-type bone marrow-derived cultured mast cell model was found to be sensitive to mast cell secretagogues, such as compound 48/80 and substance P, and higher expression levels of α subunit of a trimeric G protein, Gi1, and several Mas-related G protein-coupled receptor (Mrgpr) subtypes were observed in comparison with immature cultured mast cells. Secretagogue-induced degranulation and up-regulation of these genes was suppressed when cultured in the presence of dexamethasone. The profiles of granule constituents were drastically altered by dexamethasone. Topical application of dexamethasone down-modulated secretagogue-induced degranulation and the expression levels of several Mrgpr subtypes in cutaneous tissue. These results suggest that mast cell-mediated IgE-independent cutaneous inflammation could be suppressed by steroidal anti-inflammatory drugs through the down-regulation of G αi1 and several Mrgpr subtypes in mast cells.
Collapse
Affiliation(s)
- Keiko Yamada
- Department of Immunobiology, Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530, Japan.
| | - Hitomi Sato
- Department of Immunobiology, Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530, Japan.
| | - Kazuma Sakamaki
- Department of Immunobiology, Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530, Japan.
| | - Mayumi Kamada
- Department of Biomedical Data Intelligence, Graduate School of Medicine, Kyoto University, Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Yasushi Okuno
- Department of Biomedical Data Intelligence, Graduate School of Medicine, Kyoto University, Shogoin-Kawaharacho, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Nobuyuki Fukuishi
- Department of Pharmacology, College of Pharmacy, Kinjo Gakuin University, 2-1723 Omori, Moriyama-ku, Nagoya, Aichi, 463-8521, Japan.
| | - Kazuyuki Furuta
- Department of Immunobiology, Division of Pharmaceutical Sciences, Okayama University Graduate School of Medicine, Dentistry, and Pharmaceutical Sciences, Tsushima-naka 1-1-1, Kita-ku, Okayama 700-8530, Japan.
| | - Satoshi Tanaka
- Department of Pharmacology, Division of Pathological Sciences, Kyoto Pharmaceutical University, Misasagi Nakauchi-cho 5, Yamashina-ku, Kyoto 607-8414, Japan.
| |
Collapse
|
8
|
Meixiong J, Vasavda C, Green D, Zheng Q, Qi L, Kwatra SG, Hamilton JP, Snyder SH, Dong X. Identification of a bilirubin receptor that may mediate a component of cholestatic itch. eLife 2019; 8:44116. [PMID: 30657454 PMCID: PMC6368403 DOI: 10.7554/elife.44116] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 01/17/2019] [Indexed: 12/31/2022] Open
Abstract
Various pathologic conditions result in jaundice, a yellowing of the skin due to a buildup of bilirubin. Patients with jaundice commonly report experiencing an intense non-histaminergic itch. Despite this association, the pruritogenic capacity of bilirubin itself has not been described, and no bilirubin receptor has been identified. Here, we demonstrate that pathophysiologic levels of bilirubin excite peripheral itch sensory neurons and elicit pruritus through MRGPRs, a family of G-protein coupled receptors expressed in primary sensory neurons. Bilirubin binds and activates two MRGPRs, mouse MRGPRA1 and human MRGPRX4. In two mouse models of pathologic hyperbilirubinemia, we show that genetic deletion of either Mrgpra1 or Blvra, the gene that encodes the bilirubin-producing enzyme biliverdin reductase, attenuates itch. Similarly, plasma isolated from hyperbilirubinemic patients evoked itch in wild-type animals but not Mrgpra1-/- animals. Removing bilirubin decreased the pruritogenic capacity of patient plasma. Based on these data, targeting MRGPRs is a promising strategy for alleviating jaundice-associated itch. Jaundice causes the skin to yellow as a result of a build-up of a pigment called bilirubin. Normally, bilirubin is made in the liver and removed from the body in digestive fluid called bile, but people with liver or gallbladder problems may end up with too much bilirubin that accumulates in their blood and skin. One side effect of jaundice is intense and uncontrollable itching. Researchers are not sure what causes this itching, and there are few treatments that help to relieve it. At the molecular level, itching sensations occur when compounds bind to particular receptors on the surface of nerve cells. One family of receptors that can trigger itch is called the Mas-related G-protein Coupled Receptor (MRGPR). Could one of these receptors trigger jaundice-related itching? Now, Meixiong, Vasavda et al. show that bilirubin binds to and activates MRGPRs to cause itch in mice. Whereas injecting bilirubin into normal mice causes them to scratch, mice that have been genetically engineered to lack MRGPRs do not itch when their own bilirubin levels rise, or when they are injected with bilirubin or with plasma from patients who experience jaundice-related itching. Furthermore, removing bilirubin from the plasma of patients before it was injected into normal mice reduced the amount of itching that the mice felt. Overall, the results reported by Meixiong, Vasavda et al. suggest that drugs that prevent bilirubin from attaching to MRGPRs might help to alleviate jaundice-related itching. However, researchers must first verify that bilirubin interacts with MRGPRs in people to cause itch. If bilirubin causes itch in people like in mice, scientists could then evaluate existing drugs or make new ones to prevent bilirubin from attaching to the MRGPRs.
Collapse
Affiliation(s)
- James Meixiong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Chirag Vasavda
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Dustin Green
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Qin Zheng
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Lijun Qi
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Shawn G Kwatra
- Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - James P Hamilton
- Division of Gastroenterology and Hepatology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Solomon H Snyder
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Dermatology, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, United States.,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, United States
| |
Collapse
|
9
|
Abstract
Chronic, persistent itch is a devastating symptom that causes much suffering. In recent years, there has been great progress made in understanding the molecules, cells, and circuits underlying itch sensation. Once thought to be carried by pain-sensing neurons, itch is now believed to be capable of being transmitted by dedicated sensory labeled lines. Members of the Mas-related G protein-coupled receptor (Mrgpr) family demarcate an itch-specific labeled line in the peripheral nervous system. In the spinal cord, the expression of other proteins identifies additional populations of itch-dedicated sensory neurons. However, as evidence for labeled-line coding has mounted, studies promoting alternative itch-coding strategies have emerged, complicating our understanding of the neural basis of itch. In this review, we cover the molecules, cells, and circuits related to understanding the neural basis of itch, with a focus on the role of Mrgprs in mediating itch sensation.
Collapse
Affiliation(s)
- James Meixiong
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205, USA; ,
| | - Xinzhong Dong
- The Solomon H. Snyder Department of Neuroscience and the Center for Sensory Biology, Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205, USA; , .,Howard Hughes Medical Institute, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| |
Collapse
|
10
|
Reddy VB, Lerner EA. Activation of mas-related G-protein-coupled receptors by the house dust mite cysteine protease Der p1 provides a new mechanism linking allergy and inflammation. J Biol Chem 2017; 292:17399-17406. [PMID: 28768771 DOI: 10.1074/jbc.m117.787887] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 07/24/2017] [Indexed: 11/06/2022] Open
Abstract
Cysteine and serine proteases function via protease-activated and mas-related G-protein-coupled receptors (Mrgprs) to contribute to allergy and inflammation. Der p1 is a cysteine protease and major allergen from the house dust mite and is associated with allergic rhinitis and allergic asthma. Der p1 activates protease-activated receptor 2 and induces the release of the pro-inflammatory cytokine IL-6 from cells. However, the possibility that Der p1 acts on Mrgprs has not been considered. We report here that ratiometric calcium imaging reveals that Der p1 activates the human receptor MRGPRX1 and the mouse homolog MrgprC11, implicated previously in itch. Der p1 cleavage of N-terminal receptor peptides followed by site-directed mutagenesis of the cleavage sites links receptor activation to specific amino acid residues. Der p1 also induced the release of IL-6 from heterologous cells expressing MRGPRX1. In summary, activation of Mrgprs by the allergen Der p1 may contribute to inflammation.
Collapse
Affiliation(s)
- Vemuri B Reddy
- From the Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129
| | - Ethan A Lerner
- From the Cutaneous Biology Research Center, Massachusetts General Hospital and Harvard Medical School, Charlestown, Massachusetts 02129
| |
Collapse
|
11
|
Tiwari V, Tiwari V, He S, Zhang T, Raja SN, Dong X, Guan Y. Mas-Related G Protein-Coupled Receptors Offer Potential New Targets for Pain Therapy. Adv Exp Med Biol 2016; 904:87-103. [PMID: 26900065 DOI: 10.1007/978-94-017-7537-3_7] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The founding member of the Mas-related G-protein-coupled receptor (Mrgpr) family was discovered in 1986. Since then, many more members of this receptor family have been identified in multiple species, and their physiologic functions have been investigated widely. Because they are expressed exclusively in small-diameter primary sensory neurons, the roles of Mrgpr proteins in pain and itch have been best studied. This review will focus specifically on the current knowledge of their roles in pathological pain and the potential development of new pharmacotherapies targeted at some Mrgprs for the treatment of chronic pain. We will also discuss the limitations and future scope of this receptor family in pain treatment.
Collapse
Affiliation(s)
- Vineeta Tiwari
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Vinod Tiwari
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Shaoqiu He
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Tong Zhang
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Srinivasa N Raja
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Xinzhong Dong
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA
| | - Yun Guan
- Division of Pain Medicine, Department of Anesthesiology and Critical Care Medicine, School of Medicine, Johns Hopkins University, Baltimore, MD, 21205, USA.
| |
Collapse
|
12
|
Abstract
Intrathecal administration of the neurotoxin bombesin-saporin reduces or abolishes pruritogen-evoked scratching behavior. We investigated whether spinal neurons that respond to intradermal (ID) injection of pruritogens also respond to spinal superfusion of bombesin and vice versa. Single-unit recordings were made from superficial lumbar spinal dorsal horn neurons in anesthetized mice. We identified neurons with three search strategies: 1) ID injection of the nonhistaminergic itch mediator chloroquine, 2) spinal superfusion of bombesin, and 3) noxious pinch. All units were tested with an array of itch mediators (chloroquine, histamine, SLIGRL, BAM8-22), algogens [capsaicin, allyl isothiocyanate (AITC)], and physical stimuli (brush, pinch, noxious heat, cooling) applied to the hindlimb receptive field. The vast majority of chloroquine-responsive units also responded to bombesin. Of 26 chloroquine-sensitive units tested, most responded to SLIGRL, half responded to histamine and/or BAM8-22, and most responded to capsaicin and/or AITC as well as noxious thermal and mechanical stimuli. Of 29 bombesin-responsive units, a large majority also responded to other itch mediators as well as AITC, capsaicin, and noxious thermal and mechanical stimuli. Responses to successive applications of bombesin exhibited tachyphylaxis. In contrast, of 36 units responsive to noxious pinch, the majority (67%) did not respond to ID chloroquine or spinal bombesin. It is suggested that chloroquine- and bombesin-sensitive spinal neurons signal itch from the skin.
Collapse
Affiliation(s)
- Tasuku Akiyama
- Temple Itch Center, Department of Dermatology and Department of Anatomy and Cell Biology, Temple University School of Medicine, Philadelphia, Pennsylvania; and
| | - Mitsutoshi Tominaga
- Institute for Environmental and Gender Specific Medicine, Juntendo University Graduate School of Medicine, Urayasu, Chiba, Japan
| | - Kenji Takamori
- Institute for Environmental and Gender Specific Medicine, Juntendo University Graduate School of Medicine, Urayasu, Chiba, Japan
| | - Mirela Iodi Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California;
| | - E Carstens
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, California
| |
Collapse
|
13
|
Cevikbas F, Wang X, Akiyama T, Kempkes C, Savinko T, Antal A, Kukova G, Buhl T, Ikoma A, Buddenkotte J, Soumelis V, Feld M, Alenius H, Dillon SR, Carstens E, Homey B, Basbaum A, Steinhoff M. A sensory neuron-expressed IL-31 receptor mediates T helper cell-dependent itch: Involvement of TRPV1 and TRPA1. J Allergy Clin Immunol 2013; 133:448-60. [PMID: 24373353 DOI: 10.1016/j.jaci.2013.10.048] [Citation(s) in RCA: 471] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 10/18/2013] [Accepted: 10/23/2013] [Indexed: 01/16/2023]
Abstract
BACKGROUND Although the cytokine IL-31 has been implicated in inflammatory and lymphoma-associated itch, the cellular basis for its pruritic action is yet unclear. OBJECTIVE We sought to determine whether immune cell-derived IL-31 directly stimulates sensory neurons and to identify the molecular basis of IL-31-induced itch. METHODS We used immunohistochemistry and quantitative real-time PCR to determine IL-31 expression levels in mice and human subjects. Immunohistochemistry, immunofluorescence, quantitative real-time PCR, in vivo pharmacology, Western blotting, single-cell calcium imaging, and electrophysiology were used to examine the distribution, functionality, and cellular basis of the neuronal IL-31 receptor α in mice and human subjects. RESULTS Among all immune and resident skin cells examined, IL-31 was predominantly produced by TH2 and, to a significantly lesser extent, mature dendritic cells. Cutaneous and intrathecal injections of IL-31 evoked intense itch, and its concentrations increased significantly in murine atopy-like dermatitis skin. Both human and mouse dorsal root ganglia neurons express IL-31RA, largely in neurons that coexpress transient receptor potential cation channel vanilloid subtype 1 (TRPV1). IL-31-induced itch was significantly reduced in TRPV1-deficient and transient receptor channel potential cation channel ankyrin subtype 1 (TRPA1)-deficient mice but not in c-kit or proteinase-activated receptor 2 mice. In cultured primary sensory neurons IL-31 triggered Ca(2+) release and extracellular signal-regulated kinase 1/2 phosphorylation, inhibition of which blocked IL-31 signaling in vitro and reduced IL-31-induced scratching in vivo. CONCLUSION IL-31RA is a functional receptor expressed by a small subpopulation of IL-31RA(+)/TRPV1(+)/TRPA1(+) neurons and is a critical neuroimmune link between TH2 cells and sensory nerves for the generation of T cell-mediated itch. Thus targeting neuronal IL-31RA might be effective in the management of TH2-mediated itch, including atopic dermatitis and cutaneous T-cell lymphoma.
Collapse
Affiliation(s)
- Ferda Cevikbas
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif; Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Xidao Wang
- Department of Anatomy and the W.M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, Calif
| | - Tasuku Akiyama
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Calif
| | - Cordula Kempkes
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif
| | - Terhi Savinko
- Unit of Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland
| | - Attila Antal
- Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Gabriela Kukova
- Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Timo Buhl
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif
| | - Akihiko Ikoma
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif
| | - Joerg Buddenkotte
- Department of Dermatology, University Hospital Münster, Muenster, Germany
| | | | - Micha Feld
- Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany
| | - Harri Alenius
- Unit of Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland
| | - Stacey R Dillon
- ZymoGenetics (a Bristol-Myers Squibb Company), Seattle, Wash
| | - Earl Carstens
- Department of Neurobiology, Physiology and Behavior, University of California, Davis, Calif
| | - Bernhard Homey
- Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany.
| | - Allan Basbaum
- Department of Anatomy and the W.M. Keck Foundation Center for Integrative Neuroscience, University of California, San Francisco, San Francisco, Calif.
| | - Martin Steinhoff
- Departments of Dermatology and Surgery, University of California, San Francisco, San Francisco, Calif; Department of Dermatology, University Hospital Düsseldorf, Düsseldorf, Germany.
| |
Collapse
|
14
|
Abstract
While considerable effort has been made to investigate the neural mechanisms of pain, much less effort has been devoted to itch, at least until recently. However, itch is now gaining increasing recognition as a widespread and costly medical and socioeconomic issue. This is accompanied by increasing interest in the underlying neural mechanisms of itch, which has become a vibrant and rapidly-advancing field of research. The goal of the present forefront review is to describe the recent progress that has been made in our understanding of itch mechanisms.
Collapse
Affiliation(s)
- Tasuku Akiyama
- University of California, Davis, Department of Neurobiology, Physiology & Behavior, 1 Shields Avenue, Davis, CA 95616, United States
| | | |
Collapse
|
15
|
Nishida K, Takechi K, Akiyama T, Carstens MI, Carstens E. Scratching inhibits serotonin-evoked responses of rat dorsal horn neurons in a site- and state-dependent manner. Neuroscience 2013; 250:275-81. [PMID: 23867770 DOI: 10.1016/j.neuroscience.2013.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 06/30/2013] [Accepted: 07/04/2013] [Indexed: 10/26/2022]
Abstract
Scratching inhibits pruritogen-evoked responses of neurons in the superficial dorsal horn, implicating a spinal site for scratch inhibition of itch. We investigated if scratching differentially affects neurons depending on whether they are activated by itchy vs. painful stimuli, and if the degree of inhibition depends on the relative location of scratching. We recorded from rat lumbar dorsal horn neurons responsive to intradermal (id) microinjection of serotonin (5-hydroxytryptamine, 5-HT). During the response to 5-HT, scratch stimuli (3mm, 300 mN, 2 Hz, 20s) were delivered at the injection site within the mechanosensitive receptive field (on-site), or 4-30 mm away, outside of the receptive field (off-site). During off-site scratching, 5-HT-evoked firing was significantly attenuated followed by recovery. On-site scratching excited neurons, followed by a significant post-scratch decrease in 5-HT-evoked firing. Most neurons additionally responded to mustard oil (allyl isothiocyanate). Off-site scratching had no effect, while on-site scratching excited the neurons. These results indicate that scratching exerts a state-dependent inhibitory effect on responses of spinal neurons to pruritic but not algesic stimuli. Moreover, on-site scratching first excited neurons followed by inhibition, while off-site scratching immediately evoked the inhibition of pruritogen-evoked activity. This accounts for the suppression of itch by scratching at a distance from the site of the itchy stimulus.
Collapse
Affiliation(s)
- K Nishida
- Department of Anesthesiology and Resuscitology, Ehime University School of Medicine, Matsuyama, Japan
| | | | | | | | | |
Collapse
|