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Yang H, Chen Y, Wang L, Gan B, Yu L, Ren R, Kwok HF, Wu Y, Cao Z. The Fungal Secretory Peptide Micasin Induces Itch by Activating MRGPRX1/C11/A1 on Peripheral Neurons. J Invest Dermatol 2024:S0022-202X(24)01871-2. [PMID: 38945438 DOI: 10.1016/j.jid.2024.05.031] [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: 12/05/2023] [Revised: 05/03/2024] [Accepted: 05/07/2024] [Indexed: 07/02/2024]
Abstract
Pruritus is the leading symptom of dermatophytosis. Microsporium canis is one of the predominant dermatophytes causing dermatophytosis. However, the pruritogenic agents and the related molecular mechanisms of the dermatophyte M canis remain poorly understood. In this study, the secretion of the dermatophyte M canis was found to dose-dependently evoke itch in mice. The fungal peptide micasin secreted from M canis was then identified to elicit mouse significant scratching and itching responses. The peptide micasin was further revealed to directly activate mouse dorsal root ganglia neurons to mediate the nonhistaminergic itch. Knockout and antagonistic experiments demonstrated that MRGPRX1/C11/A1 rather than MRGPRX2/b2 activated by micasin contributed to pruritus. The chimeras and single-amino acid variants of MRGPRX1 showed that 3 domains (extracellular loop 3, transmembrane helical domain 3, and transmembrane helical domain 6) and 4 hydrophobic residues (Y99, F237, L240, and W241) of MRGPRX1 played the key role in micasin-triggered MRGPRX1 activation. Our study sheds light on the dermatophytosis-associated pruritus and may provide potential therapeutic targets and strategies against pruritus caused by dermatophytes.
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Affiliation(s)
- Haifeng Yang
- National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan, China; State Key Laboratory of Virology, Shenzhen Research Institute, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yian Chen
- State Key Laboratory of Virology, Shenzhen Research Institute, College of Life Sciences, Wuhan University, Wuhan, China
| | - Luyao Wang
- State Key Laboratory of Virology, Shenzhen Research Institute, College of Life Sciences, Wuhan University, Wuhan, China
| | - Bing Gan
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Leiye Yu
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Ruobing Ren
- Shanghai Key Laboratory of Metabolic Remodeling and Health, Institute of Metabolism and Integrative Biology, Fudan University, Shanghai, China
| | - Hang Fai Kwok
- Department of Biomedical Sciences, Faculty of Health Sciences, University of Macau, Taipa, China
| | - Yingliang Wu
- State Key Laboratory of Virology, Shenzhen Research Institute, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhijian Cao
- National "111" Center for Cellular Regulation and Molecular Pharmaceutics, Key Laboratory of Fermentation Engineering (Ministry of Education), Hubei University of Technology, Wuhan, China.
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Feng X, Zhan H, Sokol CL. Sensory neuronal control of skin barrier immunity. Trends Immunol 2024; 45:371-380. [PMID: 38653601 PMCID: PMC11102800 DOI: 10.1016/j.it.2024.03.008] [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: 03/07/2024] [Revised: 03/18/2024] [Accepted: 03/21/2024] [Indexed: 04/25/2024]
Abstract
Peripheral sensory neurons recognize diverse noxious stimuli, including microbial products and allergens traditionally thought to be targets of the mammalian immune system. Activation of sensory neurons by these stimuli leads to pain and itch responses as well as the release of neuropeptides that interact with their cognate receptors expressed on immune cells, such as dendritic cells (DCs). Neuronal control of immune cell function through neuropeptide release not only affects local inflammatory responses but can impact adaptive immune responses through downstream effects on T cell priming. Numerous neuropeptide receptors are expressed by DCs but only a few have been characterized, presenting opportunities for further investigation of the pathways by which cutaneous neuroimmune interactions modulate host immunity.
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Affiliation(s)
- Xinyi Feng
- Center for Immunology & Inflammatory Diseases, Division of Rheumatology, Allergy & Immunology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA
| | - Haoting Zhan
- Center for Immunology & Inflammatory Diseases, Division of Rheumatology, Allergy & Immunology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA; Department of Clinical Laboratory, State Key Laboratory of Complex, Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Caroline L Sokol
- Center for Immunology & Inflammatory Diseases, Division of Rheumatology, Allergy & Immunology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, 02114, USA.
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Kiełbowski K, Stańska W, Bakinowska E, Rusiński M, Pawlik A. The Role of Alarmins in the Pathogenesis of Rheumatoid Arthritis, Osteoarthritis, and Psoriasis. Curr Issues Mol Biol 2024; 46:3640-3675. [PMID: 38666958 PMCID: PMC11049642 DOI: 10.3390/cimb46040228] [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: 03/21/2024] [Revised: 04/13/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
Alarmins are immune-activating factors released after cellular injury or death. By secreting alarmins, cells can interact with immune cells and induce a variety of inflammatory responses. The broad family of alarmins involves several members, such as high-mobility group box 1, S100 proteins, interleukin-33, and heat shock proteins, among others. Studies have found that the concentrations and expression profiles of alarmins are altered in immune-mediated diseases. Furthermore, they are involved in the pathogenesis of inflammatory conditions. The aim of this narrative review is to present the current evidence on the role of alarmins in rheumatoid arthritis, osteoarthritis, and psoriasis. We discuss their potential involvement in mechanisms underlying the progression of these diseases and whether they could become therapeutic targets. Moreover, we summarize the impact of pharmacological agents used in the treatment of these diseases on the expression of alarmins.
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Affiliation(s)
- Kajetan Kiełbowski
- Department of Physiology, Pomeranian Medical University, 70-111 Szczecin, Poland; (K.K.); (E.B.); (M.R.)
| | - Wiktoria Stańska
- Department of Medical Biology, Medical University of Warsaw, 00-575 Warsaw, Poland;
| | - Estera Bakinowska
- Department of Physiology, Pomeranian Medical University, 70-111 Szczecin, Poland; (K.K.); (E.B.); (M.R.)
| | - Marcin Rusiński
- Department of Physiology, Pomeranian Medical University, 70-111 Szczecin, Poland; (K.K.); (E.B.); (M.R.)
| | - Andrzej Pawlik
- Department of Physiology, Pomeranian Medical University, 70-111 Szczecin, Poland; (K.K.); (E.B.); (M.R.)
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Pantoja CJ, Li H, Rodante J, Keel A, Sorokin AV, Svedbom A, Teague HL, Stahle M, Mehta NN, Playford MP. Serum Beta-Defensin-2 is a biomarker for psoriasis but not subclinical atherosclerosis: Role of IL17a, PI-3 kinase and Rac1. JEADV CLINICAL PRACTICE 2024; 3:150-159. [PMID: 38646149 PMCID: PMC11031204 DOI: 10.1002/jvc2.278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 09/20/2023] [Indexed: 04/23/2024]
Abstract
Background Beta-defensins (BDs) are antimicrobial peptides secreted upon epithelial injury. Both chemotactic and antimicrobial properties of BDs function as initial steps in host defense and prime the adaptive immune system in the body. Psoriasis, a chronic immune-mediated inflammatory disease, has both visible cutaneous manifestations as well as known associations with higher incidence of cardiometabolic complications and vascular inflammation. Objectives We aimed to investigate the circulating expression of beta-defensin-2 (BD2) in psoriasis at baseline compared to control subjects, along with changes in BD2 levels following biologic treatment at one-year. The contribution of BD2 to subclinical atherosclerosis is also assessed. In addition, we have sought to unravel signaling mechanisms linking inflammation with BD2 expression. Methods Multimodality imaging as well inflammatory biomarker assays were performed in biologic naïve psoriasis (n=71) and non-psoriasis (n=53) subjects. A subset of psoriasis patients were followed for one-year after biological intervention (anti-Tumor Necrosis Factor-α (TNFα), n=30; anti-Interleukin17A (IL17A), n=21). Measurements of circulating BD2 were completed by Enzyme-Linked Immunosorbent Assay (ELISA). Using HaCaT transformed keratinocytes, expression of BD2 upon cytokine treatment was assessed by quantitative polymerase chain reaction (qPCR) and ELISA. Results Herein, we confirm that human circulating BD2 levels associate with psoriasis, which attenuate upon biologic interventions (anti-TNFα, anti-IL-17A). A link between circulating BD2 and sub-clinical atherosclerosis markers was not observed. Furthermore, we demonstrate that IL-17A-driven BD2 expression occurs in a Phosphatidylinositol 3-kinase (PI3-kinase) and Rac1 GTPase-dependent manner. Conclusions Our findings expand on the potential role of BD2 as a tractable biomarker in psoriasis patients and describes the role of an IL-17A-PI3-kinase/Rac signaling axis in regulating BD2 levels in keratinocytes.
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Affiliation(s)
- CJ. Pantoja
- Section of Inflammation and Cardiometabolic Diseases, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland
| | - H. Li
- Section of Inflammation and Cardiometabolic Diseases, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland
| | - J. Rodante
- Section of Inflammation and Cardiometabolic Diseases, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland
| | - A. Keel
- Section of Inflammation and Cardiometabolic Diseases, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland
| | - AV. Sorokin
- Section of Inflammation and Cardiometabolic Diseases, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland
| | - A. Svedbom
- Division of Dermatology and Venerology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - HL. Teague
- Section of Inflammation and Cardiometabolic Diseases, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland
| | - M. Stahle
- Division of Dermatology and Venerology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden
| | - NN. Mehta
- Section of Inflammation and Cardiometabolic Diseases, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland
| | - MP. Playford
- Section of Inflammation and Cardiometabolic Diseases, National Heart, Lung and Blood Institute, National Institute of Health, Bethesda, Maryland
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5
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Gour N, Dong X. The MRGPR family of receptors in immunity. Immunity 2024; 57:28-39. [PMID: 38198852 PMCID: PMC10825802 DOI: 10.1016/j.immuni.2023.12.012] [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: 10/13/2023] [Revised: 12/03/2023] [Accepted: 12/13/2023] [Indexed: 01/12/2024]
Abstract
The discovery of Mas-related G protein-coupled receptors (Mrgprs) has opened a compelling chapter in our understanding of immunity and sensory biology. This family of receptors, with their unique expression and diverse ligands, has emerged as key players in inflammatory states and hold the potential to alleviate human diseases. This review will focus on the members of this receptor family expressed on immune cells and how they govern immune and neuro-immune pathways underlying various physiological and pathological states. Immune cell-specific Mrgprs have been shown to control a variety of manifestations, including adverse drug reactions, inflammatory conditions, bacterial immunity, and the sensing of environmental exposures like allergens and irritants.
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Affiliation(s)
- Naina Gour
- Solomon H. Snyder Department of Neuroscience, 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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Kupari J, Ernfors P. Molecular taxonomy of nociceptors and pruriceptors. Pain 2023; 164:1245-1257. [PMID: 36718807 PMCID: PMC10184562 DOI: 10.1097/j.pain.0000000000002831] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/10/2022] [Accepted: 11/21/2022] [Indexed: 02/01/2023]
Affiliation(s)
- Jussi Kupari
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
| | - Patrik Ernfors
- Division of Molecular Neurobiology, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Stockholm, Sweden
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7
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Oleszycka E, Kwiecien K, Kwiecinska P, Morytko A, Pocalun N, Camacho M, Brzoza P, Zabel BA, Cichy J. Soluble mediators in the function of the epidermal-immune-neuro unit in the skin. Front Immunol 2022; 13:1003970. [PMID: 36330530 PMCID: PMC9623011 DOI: 10.3389/fimmu.2022.1003970] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 10/05/2022] [Indexed: 09/19/2023] Open
Abstract
Skin is the largest, environmentally exposed (barrier) organ, capable of integrating various signals into effective defensive responses. The functional significance of interactions among the epidermis and the immune and nervous systems in regulating and maintaining skin barrier function is only now becoming recognized in relation to skin pathophysiology. This review focuses on newly described pathways that involve soluble mediator-mediated crosstalk between these compartments. Dysregulation of these connections can lead to chronic inflammatory diseases and/or pathologic conditions associated with chronic pain or itch.
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Affiliation(s)
- Ewa Oleszycka
- Department of Immunology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Kamila Kwiecien
- Department of Immunology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Patrycja Kwiecinska
- Department of Immunology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Agnieszka Morytko
- Department of Immunology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Natalia Pocalun
- Department of Immunology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Michelle Camacho
- Department of Immunology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Piotr Brzoza
- Department of Immunology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
| | - Brian A. Zabel
- Palo Alto Veterans Institute for Research, VA Palo Alto Health Care System, Palo Alto, CA, United States
| | - Joanna Cichy
- Department of Immunology, Faculty of Biochemistry, Biophysics and Biotechnology, Jagiellonian University, Kraków, Poland
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8
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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: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [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.
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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.
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9
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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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10
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Tominaga M, Takamori K. Peripheral itch sensitization in atopic dermatitis. Allergol Int 2022; 71:265-277. [PMID: 35624035 DOI: 10.1016/j.alit.2022.04.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2022] [Accepted: 04/06/2022] [Indexed: 02/07/2023] Open
Abstract
Atopic dermatitis is a skin disorder caused by skin dryness and barrier dysfunction, resulting in skin inflammation and chronic itch (or pruritus). The pathogenesis of atopic dermatitis is thought to be initiated by a lowering of the itch threshold due to dry skin. This lowering of the itch threshold is at least partially due to the increase in intraepidermal nerve fibers and sensitization of sensory nerves by interleukin (IL)-33 produced and secreted by keratinocytes. Such skin is easily prone to itch due to mechanical stimuli, such as rubbing of clothing and chemical stimuli from itch mediators. In patients with atopic dermatitis, once itch occurs, further itch is induced by scratching, and the associated scratching breaks down the skin barrier. Disruption of the skin barrier allows entry into the epidermis of external foreign substances, such as allergens derived from house dust mites, leading to an increased induction of type 2 inflammatory responses. As a result, type 2 cytokines IL-4, IL-13, and IL-31 are mainly secreted by Th2 cells, and their action on sensory nerve fibers causes further itch sensitization. These sequences of events are thought to occur simultaneously in patients with atopic dermatitis, leading to a vicious itch-scratch cycle. This vicious cycle becomes a negative spiral that leads to disease burden. Therefore, controlling itch is essential for the treatment of atopic dermatitis. In this review, we summarize and discuss advances in the mechanisms of peripheral itch sensitization in atopic dermatitis, focusing on skin barrier-neuro-immune triadic connectivity.
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11
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Humeau M, Boniface K, Bodet C. Cytokine-Mediated Crosstalk Between Keratinocytes and T Cells in Atopic Dermatitis. Front Immunol 2022; 13:801579. [PMID: 35464457 PMCID: PMC9022745 DOI: 10.3389/fimmu.2022.801579] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 03/07/2022] [Indexed: 01/22/2023] Open
Abstract
Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by barrier dysfunction, dysregulated immune response, and dysbiosis with increased Staphylococcus aureus colonization. Infiltration of various T helper cell subsets into lesional skin and subsequent cytokine release are a hallmark of AD. Release of cytokines by both T cells and keratinocytes plays a key role in skin inflammation and drives many AD features. This review aims to discuss cytokine-mediated crosstalk between T cells and keratinocytes in AD pathogenesis and the potential impact of virulence factors produced by Staphylococcus aureus on these interactions.
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Affiliation(s)
- Mélanie Humeau
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines LITEC UR 15560, Université de Poitiers, Poitiers, France
| | - Katia Boniface
- ImmunoConcEpT, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 5164, University of Bordeaux, Bordeaux, France
| | - Charles Bodet
- Laboratoire Inflammation Tissus Epithéliaux et Cytokines LITEC UR 15560, Université de Poitiers, Poitiers, France
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