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Lerner L, Babina M, Zuberbier T, Stevanovic K. Beyond Allergies-Updates on The Role of Mas-Related G-Protein-Coupled Receptor X2 in Chronic Urticaria and Atopic Dermatitis. Cells 2024; 13:220. [PMID: 38334612 PMCID: PMC10854933 DOI: 10.3390/cells13030220] [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: 10/09/2023] [Revised: 12/14/2023] [Accepted: 01/19/2024] [Indexed: 02/10/2024] Open
Abstract
Mast cells (MCs) are an important part of the immune system, responding both to pathogens and toxins, but they also play an important role in allergic diseases, where recent data show that non-IgE-mediated activation is also of relevance, especially in chronic urticaria (CU) and atopic dermatitis (AD). Skin MCs express Mas-related G-protein-coupled receptor X2 (MRGPRX2), a key protein in non-IgE-dependent MC degranulation, and its overactivity is one of the triggering factors for the above-mentioned diseases, making MRGPRX2 a potential therapeutic target. Reviewing the latest literature revealed our need to focus on the discovery of MRGPRX2 activators as well as the ongoing vast research towards finding specific MRGPRX2 inhibitors for potential therapeutic approaches. Most of these studies are in their preliminary stages, with one drug currently being investigated in a clinical trial. Future studies and improved model systems are needed to verify whether any of these inhibitors may have the potential to be the next therapeutic treatment for CU, AD, and other pseudo-allergic reactions.
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Affiliation(s)
- Liron Lerner
- Institute of Allergology, Charité—Universitätsmedizin Berlin, 12203 Berlin, Germany; (L.L.); (M.B.); (T.Z.)
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Allergology and Immunology, 12203 Berlin, Germany
| | - Magda Babina
- Institute of Allergology, Charité—Universitätsmedizin Berlin, 12203 Berlin, Germany; (L.L.); (M.B.); (T.Z.)
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Allergology and Immunology, 12203 Berlin, Germany
| | - Torsten Zuberbier
- Institute of Allergology, Charité—Universitätsmedizin Berlin, 12203 Berlin, Germany; (L.L.); (M.B.); (T.Z.)
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Allergology and Immunology, 12203 Berlin, Germany
| | - Katarina Stevanovic
- Institute of Allergology, Charité—Universitätsmedizin Berlin, 12203 Berlin, Germany; (L.L.); (M.B.); (T.Z.)
- Fraunhofer Institute for Translational Medicine and Pharmacology (ITMP), Allergology and Immunology, 12203 Berlin, Germany
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Zhou Y, Chen R, Kong L, Sun Y, Deng J. Neuroimmune communication in allergic rhinitis. Front Neurol 2023; 14:1282130. [PMID: 38178883 PMCID: PMC10764552 DOI: 10.3389/fneur.2023.1282130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 12/06/2023] [Indexed: 01/06/2024] Open
Abstract
The prevalence rate of allergic rhinitis (AR) is high worldwide. The inhalation of allergens induces AR, which is an immunoglobulin E-mediated and type 2 inflammation-driven disease. Recently, the role of neuroimmune communication in AR pathogenesis has piqued the interest of the scientific community. Various neuropeptides, such as substance P (SP), vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), nerve growth factor (NGF), and neuromedin U (NMU), released via "axon reflexes" or "central sensitization" exert regulatory effects on immune cells to elicit "neurogenic inflammation," which contributes to nasal hyperresponsiveness (NHR) in AR. Additionally, neuropeptides can be produced in immune cells. The frequent colocalization of immune and neuronal cells at certain anatomical regions promotes the establishment of neuroimmune cell units, such as nerve-mast cells, nerve-type 2 innate lymphoid cells (ILC2s), nerve-eosinophils and nerve-basophils units. Receptors expressed both on immune cells and neurons, such as TRPV1, TRPA1, and Mas-related G protein-coupled receptor X2 (MRGPRX2) mediate AR pathogenesis. This review focused on elucidating the mechanisms underlying neuroimmune communication in AR.
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Affiliation(s)
- Yi Zhou
- Department of Otolaryngology, Jiaxing University Master Degree Cultivation Base, Zhejiang Chinese Medical University, Zhejiang, China
- Department of Otolaryngology, The First Hospital of Jiaxing, Jiaxing, China
| | - Ru Chen
- Department of Otolaryngology, The First Hospital of Jiaxing, Jiaxing, China
| | - Lili Kong
- Department of Otolaryngology, Jiaxing University Master Degree Cultivation Base, Zhejiang Chinese Medical University, Zhejiang, China
- Department of Otolaryngology, The First Hospital of Jiaxing, Jiaxing, China
| | - Yaoyao Sun
- Department of Otolaryngology, The First Hospital of Jiaxing, Jiaxing, China
| | - Jing Deng
- Department of Otolaryngology, Jiaxing University Master Degree Cultivation Base, Zhejiang Chinese Medical University, Zhejiang, China
- Department of Otolaryngology, The First Hospital of Jiaxing, Jiaxing, China
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Chanpong A, Alves MM, Bonora E, De Giorgio R, Thapar N. Evaluating the molecular and genetic mechanisms underlying gut motility disorders. Expert Rev Gastroenterol Hepatol 2023; 17:1301-1312. [PMID: 38117595 DOI: 10.1080/17474124.2023.2296558] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 12/14/2023] [Indexed: 12/22/2023]
Abstract
INTRODUCTION Gastrointestinal (GI) motility disorders comprise a wide range of different diseases affecting the structural or functional integrity of the GI neuromusculature. Their clinical presentation and burden of disease depends on the predominant location and extent of gut involvement as well as the component of the gut neuromusculature affected. AREAS COVERED A comprehensive literature review was conducted using the PubMed and Medline databases to identify articles related to GI motility and functional disorders, published between 2016 and 2023. In this article, we highlight the current knowledge of molecular and genetic mechanisms underlying GI dysmotility, including disorders of gut-brain interaction, which involve both GI motor and sensory disturbance. EXPERT OPINION Although the pathophysiology and molecular mechanisms underlying many such disorders remain unclear, recent advances in the assessment of intestinal tissue samples, genetic testing with the application of 'omics' technologies and the use of animal models will provide better insights into disease pathogenesis as well as opportunities to improve therapy.
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Affiliation(s)
- Atchariya Chanpong
- Division of Gastroenterology and Hepatology, Department of Pediatrics, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand
- Neurogastroenterology & Motility Unit, Gastroenterology Department, Great Ormond Street Hospital for Children, London, UK
| | - Maria M Alves
- Department of Clinical Genetics, Erasmus University Medical Center, Sophia Children's Hospital, Rotterdam, The Netherlands
| | - Elena Bonora
- Department of Medical and Surgical Sciences, DIMEC, University of Bologna, Bologna, Italy
- U.O. Genetica Medica, IRCCS Azienda Ospedaliero-Universitaria di Bologna, AOUB, Bologna, Italy
| | - Roberto De Giorgio
- Department of Translational Sciences, University of Ferrara, Ferrara, Italy
| | - Nikhil Thapar
- Stem Cells and Regenerative Medicine, UCL Great Ormond Street Institute of Child Health, London, UK
- Gastroenterology, Hepatology and Liver Transplant, Queensland Children's Hospital, Brisbane, Australia
- School of Medicine, University of Queensland, Brisbane, Australia
- Woolworths Centre for Child Nutrition Research, Queensland University of Technology, Brisbane, Australia
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Baldo BA. MRGPRX2, drug pseudoallergies, inflammatory diseases, mechanisms and distinguishing MRGPRX2- and IgE/FcεRI-mediated events. Br J Clin Pharmacol 2023; 89:3232-3246. [PMID: 37430437 DOI: 10.1111/bcp.15845] [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: 04/11/2023] [Revised: 06/22/2023] [Accepted: 06/30/2023] [Indexed: 07/12/2023] Open
Abstract
MRGPRX2, a novel Gaq -coupled human mast cell receptor, mediates non-immune adverse reactions without the involvement of antibody priming. Constitutively expressed by human skin mast cells, MRGPRX2 modulates cell degranulation producing pseudoallergies manifesting as itch, inflammation and pain. The term pseudoallergy is defined in relation to adverse drug reactions in general and immune/non-immune-mediated reactions in particular. A list of drugs with MRGPRX2 activity is presented, including a detailed examination of three important and widely used approved therapies: neuromuscular blockers, quinolones and opioids. For the clinician, the significance of MRGPRX2 is considered as an aid in distinguishing and ultimately identifying specific immune and non-immune inflammatory reactions. Anaphylactoid/anaphylactic reactions, neurogenic inflammation and inflammatory diseases with a clear or strongly suspected association with MRGPRX2 activation are examined. Inflammatory diseases include chronic urticaria, rosacea, atopic dermatitis, allergic contact dermatitis, mastocytosis, allergic asthma, ulcerative colitis and rheumatoid arthritis. MRGPRX2- and allergic IgE/FcεRI-mediated reactions may be clinically similar. Importantly, the usual testing procedures do not distinguish the two mechanisms. Currently, identification of MRGPRX2 activation and diagnosis of pseudoallergic reactions is generally viewed as a process of exclusion once other non-immune and immune processes, particularly IgE/FcεRI-mediated degranulation of mast cells, are ruled out. This does not take into account that MRGPRX2 signals via β-arrestin, which can be utilized to detect MRGPRX2 activation by employing MRGPRX2 transfected cells to assess MRGPRX2 activation via two pathways, the G-protein-independent β-arrestin pathway and the G-protein-dependent Ca2+ pathway. Testing procedures, interpretations for distinguishing mechanisms, patient diagnosis, agonist identification and drug safety evaluations are addressed.
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Affiliation(s)
- Brian A Baldo
- Royal North Shore Hospital of Sydney, Kolling Institute of Medical Research, Sydney, New South Wales, Australia
- Department of Medicine, University of Sydney, Sydney, New South Wales, Australia
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Vanuytsel T, Bercik P, Boeckxstaens G. Understanding neuroimmune interactions in disorders of gut-brain interaction: from functional to immune-mediated disorders. Gut 2023; 72:787-798. [PMID: 36657961 PMCID: PMC10086308 DOI: 10.1136/gutjnl-2020-320633] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 12/08/2022] [Indexed: 01/21/2023]
Abstract
Functional gastrointestinal disorders-recently renamed into disorders of gut-brain interaction-such as irritable bowel syndrome and functional dyspepsia are highly prevalent conditions with bothersome abdominal symptoms in the absence of structural abnormalities. While traditionally considered as motility disorders or even psychosomatic conditions, our understanding of the pathophysiology has evolved significantly over the last two decades. Initial observations of subtle mucosal infiltration with immune cells, especially mast cells and eosinophils, are since recently being backed up by mechanistic evidence demonstrating increased release of nociceptive mediators by immune cells and the intestinal epithelium. These mediators can activate sensitised neurons leading to visceral hypersensitivity with bothersome symptoms. The interaction between immune activation and an impaired barrier function of the gut is most likely a bidirectional one with alterations in the microbiota, psychological stress and food components as upstream players in the pathophysiology. Only few immune-targeting treatments are currently available, but an improved understanding through a multidisciplinary scientific approach will hopefully identify novel, more precise treatment targets with ultimately better outcomes.
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Affiliation(s)
- Tim Vanuytsel
- Translational Research Center for Gastrointestinal Disorders (TARGID), Department of Chronic Diseases and Metabolism (ChroMeta), KU Leuven, Leuven, Belgium.,Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium
| | - Premysl Bercik
- Faculty of Health Sciences, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada
| | - Guy Boeckxstaens
- Translational Research Center for Gastrointestinal Disorders (TARGID), Department of Chronic Diseases and Metabolism (ChroMeta), KU Leuven, Leuven, Belgium .,Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium
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Camilleri M, Boeckxstaens G. Irritable bowel syndrome: treatment based on pathophysiology and biomarkers. Gut 2023; 72:590-599. [PMID: 36307180 PMCID: PMC9990119 DOI: 10.1136/gutjnl-2022-328515] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 10/16/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVE To appraise the evidence that pathophysiological mechanisms and individualised treatment directed at those mechanisms provide an alternative approach to the treatment of patients with irritable bowel syndrome (IBS). DESIGN A PubMED-based literature review of mechanisms and treatment of IBS was conducted independently by the two authors, and any differences of perspective or interpretation of the literature were resolved following discussion. RESULTS The availability of several noninvasive clinical tests can appraise the mechanisms responsible for symptom generation in IBS, including rectal evacuation disorders, abnormal transit, visceral hypersensitivity or hypervigilance, bile acid diarrhoea, sugar intolerances, barrier dysfunction, the microbiome, immune activation and chemicals released by the latter mechanism. The basic molecular mechanisms contributing to these pathophysiologies are increasingly recognised, offering opportunities to intervene with medications directed specifically to food components, receptors and potentially the microbiome. Although the evidence supporting interventions for each mechanism is not at the same level of proof, the current state-of-the-art provides the opportunity to advance the practice from treatment based on symptoms to individualisation of treatment guided by pathophysiology and clinically identified biomarkers. CONCLUSION These advances augur well for the implementation of evidence-based individualised treatment for patients with IBS based on actionable biomarkers or psychological disturbances.
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Affiliation(s)
- Michael Camilleri
- Clinical Enteric Neuroscience Translational and Epidemiological Research (CENTER), Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, Minnesota, USA
| | - Guy Boeckxstaens
- Center of Intestinal Neuroimmune Interaction, Division of Gastroenterology, Translational Research Center for GI Disorders (TARGID), Leuven University, Leuven, Belgium
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Iribarren C, Nordlander S, Sundin J, Isaksson S, Savolainen O, Törnblom H, Magnusson MK, Simrén M, Öhman L. Fecal luminal factors from patients with irritable bowel syndrome induce distinct gene expression of colonoids. Neurogastroenterol Motil 2022; 34:e14390. [PMID: 35485994 PMCID: PMC9786662 DOI: 10.1111/nmo.14390] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Revised: 03/24/2022] [Accepted: 04/11/2022] [Indexed: 12/30/2022]
Abstract
BACKGROUND Alteration of the host-microbiota cross talk at the intestinal barrier may participate in the pathophysiology of irritable bowel syndrome (IBS). Therefore, we aimed to determine effects of fecal luminal factors from IBS patients on the colonic epithelium using colonoids. METHODS Colon-derived organoid monolayers, colonoids, generated from a healthy subject, underwent stimulation with fecal supernatants from healthy subjects and IBS patients with predominant diarrhea, phosphate-buffered saline (PBS), or lipopolysaccharide (LPS). Cytokines in cell cultures and fecal LPS were measured by ELISA and mRNA gene expression of monolayers was analyzed using Qiagen RT2 Profiler PCR Arrays. The fecal microbiota profile was determined by the GA-map™ dysbiosis test and the fecal metabolite profile was analyzed by untargeted liquid chromatography/mass spectrometry. KEY RESULTS Colonoid monolayers stimulated with fecal supernatants from healthy subjects (n = 7), PBS (n = 4) or LPS (n = 3) presented distinct gene expression profiles, with some overlap (R2 Y = 0.70, Q2 = 0.43). Addition of fecal supernatants from healthy subjects and IBS patients (n = 9) gave rise to different gene expression profiles of the colonoid monolayers (R2 Y = 0.79, Q2 = 0.64). Genes (n = 22) related to immune response (CD1D, TLR5) and barrier integrity (CLDN15, DSC2) contributed to the separation. Levels of proinflammatory cytokines in colonoid monolayer cultures were comparable when stimulated with fecal supernatants from either donor types. Fecal microbiota and metabolite profiles, but not LPS content, differed between the study groups. CONCLUSIONS Fecal luminal factors from IBS patients induce a distinct colonic epithelial gene expression, potentially reflecting the disease pathophysiology. The culture of colonoids from healthy subjects with fecal supernatants from IBS patients may facilitate the exploration of IBS related intestinal micro-environmental and barrier interactions.
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Affiliation(s)
- Cristina Iribarren
- Department of Microbiology and ImmunologyInstitute of BiomedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden,Department of Molecular and Clinical MedicineInstitute of MedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Sofia Nordlander
- Department of Microbiology and ImmunologyInstitute of BiomedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden,Department of Molecular and Clinical MedicineInstitute of MedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Johanna Sundin
- Department of Microbiology and ImmunologyInstitute of BiomedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Stefan Isaksson
- Department of Microbiology and ImmunologyInstitute of BiomedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Otto Savolainen
- Chalmers Mass Spectrometry InfrastructureDepartment of Biology and Biological EngineeringChalmers University of TechnologyGothenburgSweden
| | - Hans Törnblom
- Department of Molecular and Clinical MedicineInstitute of MedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Maria K. Magnusson
- Department of Microbiology and ImmunologyInstitute of BiomedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
| | - Magnus Simrén
- Department of Molecular and Clinical MedicineInstitute of MedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden,Center for Functional GI and Motility DisordersUniversity of North CarolinaChapel HillNorth CarolinaUSA
| | - Lena Öhman
- Department of Microbiology and ImmunologyInstitute of BiomedicineSahlgrenska AcademyUniversity of GothenburgGothenburgSweden
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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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Ceulemans M, Jacobs I, Wauters L, Vanuytsel T. Immune Activation in Functional Dyspepsia: Bystander Becoming the Suspect. Front Neurosci 2022; 16:831761. [PMID: 35557605 PMCID: PMC9087267 DOI: 10.3389/fnins.2022.831761] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
Disorders of gut-brain interaction (DGBI), formerly termed functional gastrointestinal disorders (FGID), are highly prevalent although exact pathophysiological mechanisms remain unclear. Intestinal immune activation has been recognized, but increasing evidence supports a pivotal role for an active inflammatory state in these disorders. In functional dyspepsia (FD), marked eosinophil and mast cell infiltration has been repeatedly demonstrated and associations with symptoms emphasize the relevance of an eosinophil-mast cell axis in FD pathophysiology. In this Review, we highlight the importance of immune activation in DGBI with a focus on FD. We summarize eosinophil biology in both homeostasis and inflammatory processes. The evidence for immune activation in FD is outlined with attention to alterations on both cellular and molecular level, and how these may contribute to FD symptomatology. As DGBI are complex and multifactorial conditions, we shed light on factors associated to, and potentially influencing immune activation, including bidirectional gut-brain interaction, allergy and the microbiota. Crucial studies reveal a therapeutic benefit of treatments targeting immune activation, suggesting that specific anti-inflammatory therapies could offer renewed hope for at least a subset of DGBI patients. Lastly, we explore the future directions for DGBI research that could advance the field. Taken together, emerging evidence supports the recognition of FD as an immune-mediated organic-based disorder, challenging the paradigm of a strictly functional nature.
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Affiliation(s)
- Matthias Ceulemans
- Department of Chronic Diseases and Metabolism, Translational Research Center for Gastrointestinal Disorders (TARGID), Katholieke Universiteit Leuven, Leuven, Belgium
| | - Inge Jacobs
- Allergy and Clinical Immunology Research Group, Department of Microbiology, Immunology and Transplantation, Katholieke Universiteit Leuven, Leuven, Belgium
| | - Lucas Wauters
- Department of Chronic Diseases and Metabolism, Translational Research Center for Gastrointestinal Disorders (TARGID), Katholieke Universiteit Leuven, Leuven, Belgium
- Department of Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium
| | - Tim Vanuytsel
- Department of Chronic Diseases and Metabolism, Translational Research Center for Gastrointestinal Disorders (TARGID), Katholieke Universiteit Leuven, Leuven, Belgium
- Department of Gastroenterology and Hepatology, University Hospitals Leuven, Leuven, Belgium
- *Correspondence: Tim Vanuytsel,
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Aguilera-Lizarraga J, Hussein H, Boeckxstaens GE. Immune activation in irritable bowel syndrome: what is the evidence? Nat Rev Immunol 2022; 22:674-686. [PMID: 35296814 DOI: 10.1038/s41577-022-00700-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/18/2022] [Indexed: 12/15/2022]
Abstract
Irritable bowel syndrome (IBS) is a chronic functional gastrointestinal disorder that is characterized by abdominal pain and an altered defecation pattern. It affects between 5 and 20% of the general population and can seriously impact quality of life. The pathophysiology of IBS is rather complex and multifactorial including, for example, altered signalling by the gut-brain axis, dysbiosis, abnormal visceral pain signalling and intestinal immune activation. The latter has gained particular interest in recent years, with growing insight into the bidirectional communication between the nervous system and the immune system. In this Review, we detail the current evidence suggesting that immune activation contributes to the pathology seen in patients with IBS and discuss the potential mechanisms involved. Moreover, we describe how immune mediators, particularly those released by mast cells, can directly activate or sensitize pain-transmitting nerves, leading to increased pain signalling and abdominal pain. Finally, we discuss the potential of interventions targeting immune activation as a new therapeutic strategy for patients suffering from IBS.
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Affiliation(s)
- Javier Aguilera-Lizarraga
- Laboratory for Intestinal Neuroimmune Interactions, Translational Research Centre for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Hind Hussein
- Laboratory for Intestinal Neuroimmune Interactions, Translational Research Centre for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium
| | - Guy E Boeckxstaens
- Laboratory for Intestinal Neuroimmune Interactions, Translational Research Centre for Gastrointestinal Disorders, Department of Chronic Diseases, Metabolism and Ageing, KU Leuven, Leuven, Belgium.
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Mas-Related G Protein-Coupled Receptors (Mrgprs) as Mediators of Gut Neuro-Immune Signaling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1383:259-269. [PMID: 36587165 DOI: 10.1007/978-3-031-05843-1_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Over the past 15 years, the research field on Mas-related G protein-coupled receptors (Mrgprs), a relatively new family of rhodopsin A-like G protein-coupled receptors, has expanded enormously, and a plethora of recent studies have provided evidence that several of these Mrgpr family members play an important role in the underlying mechanisms of itch and pain, as well as in the initiation and modulation of inflammatory/allergic responses. Initial studies mainly focused on the skin, but more recently also visceral organs such as the respiratory and gastrointestinal (GI) tracts emerged as sites for Mrgpr involvement. It has become clear that the gastrointestinal tract and its innervation in close association with the immune system represent a novel expression site for Mrgprs where they contribute to the interoceptive mechanisms maintaining homeostasis and might constitute promising targets in chronic abdominal pain disorders. In this short review, we provide an update of our current knowledge on the expression, distribution, and function of members of this Mrgpr family in intrinsic and extrinsic neuro-immune pathways related to the gastrointestinal tract, their mediatory role(s) in gut neuro-immune signaling, and their involvement in visceral afferent (nociceptive) pathways.
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12
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Aguilera-Lizarraga J, Florens M, Hussein H, Boeckxstaens G. Local immune response as novel disease mechanism underlying abdominal pain in patients with irritable bowel syndrome. Acta Clin Belg 2021; 77:889-896. [PMID: 34709996 DOI: 10.1080/17843286.2021.1996069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVES Irritable bowel syndrome (IBS) is the most frequently diagnosed functional gastrointestinal disorder, with a prevalence of up to 25% of the global population. IBS patients suffer from abnormal abdominal pain, or visceral hypersensitivity (VHS), associated with altered bowel habits in the absence of an organic detectable cause. The pathophysiology of the disease is incompletely understood, but the dysregulation of the brain-gut axis is well established in IBS. METHODS IBS onset is mainly triggered by infectious gastroenteritis, psychological factors, and dietary factors, but genetic predispositions and intestinal dysbiosis might also play a role. Additionally, immune activation, and particularly chronic mast cell activation, have been shown to underlie the development of abdominal pain in IBS. RESULTS By releasing increased levels of mediators, including histamine, mast cells sensitize enteric nociceptors and lead to VHS development. The mechanisms underlying aberrant mast cell activation in IBS are still under investigation, but we recently showed that a local break in oral tolerance to food antigens led to IgE-mediated mast cell activation and food-induced abdominal pain in preclinical models and in IBS patients. CONCLUSION The concept of food-mediated VHS highlights the potential of therapies targeting upstream mechanisms of mast cell sensitization to treat IBS.
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Affiliation(s)
- J. Aguilera-Lizarraga
- Center of Intestinal Neuro-immune Interaction, Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Belgium
| | - M. Florens
- Center of Intestinal Neuro-immune Interaction, Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Belgium
| | - H. Hussein
- Center of Intestinal Neuro-immune Interaction, Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Belgium
| | - G. Boeckxstaens
- Center of Intestinal Neuro-immune Interaction, Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, Belgium
- Department of Gastroenterology & Hepatology, UZ Leuven, Leuven, Belgium
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van Thiel IAM, de Jonge WJ, Chiu IM, van den Wijngaard RM. Microbiota-neuroimmune cross talk in stress-induced visceral hypersensitivity of the bowel. Am J Physiol Gastrointest Liver Physiol 2020; 318:G1034-G1041. [PMID: 32308040 PMCID: PMC7642838 DOI: 10.1152/ajpgi.00196.2019] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Visceral hypersensitivity of the lower gastrointestinal tract, defined as an increased response to colorectal distension, frequently prompts episodes of debilitating abdominal pain in irritable bowel syndrome (IBS). Although the pathophysiology of IBS is not yet fully elucidated, it is well known that stress is a major risk factor for development and acts as a trigger of pain sensation. Stress modulates both immune responses as well as the gut microbiota and vice versa. Additionally, either microbes themselves or through involvement of the immune system, activate or sensitize afferent nociceptors. In this paper, we review current knowledge on the influence of stress along the gut-brain-microbiota axis and exemplify relevant neuroimmune cross talk mechanisms in visceral hypersensitivity, working toward understanding how gut microbiota-neuroimmune cross talk contributes to visceral pain sensation in IBS patients.
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Affiliation(s)
- Isabelle A. M. van Thiel
- 1Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Centers, Amsterdam, The Netherlands,2Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Wouter J. de Jonge
- 1Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Centers, Amsterdam, The Netherlands,2Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands,3Department of Gastroenterology and Hepatology, Amsterdam University Medical Centers, Amsterdam, The Netherlands,4Department of General, Visceral, Thoracic, and Vascular Surgery, University Hospital Bonn, Bonn, Germany
| | - Isaac M. Chiu
- 5Department of Immunology, Harvard Medical School. Boston, Massachusetts
| | - Rene M. van den Wijngaard
- 1Tytgat Institute for Liver and Intestinal Research, Amsterdam University Medical Centers, Amsterdam, The Netherlands,2Department of Gastroenterology and Hepatology, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands,3Department of Gastroenterology and Hepatology, Amsterdam University Medical Centers, Amsterdam, The Netherlands
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The pseudo-allergic/neurogenic route of mast cell activation via MRGPRX2: discovery, functional programs, regulation, relevance to disease, and relation with allergic stimulation. ACTA ACUST UNITED AC 2020. [DOI: 10.1097/itx.0000000000000032] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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