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Barchi A, Vespa E, Passaretti S, Dell’Anna G, Fasulo E, Yacoub MR, Albarello L, Sinagra E, Massimino L, Ungaro F, Danese S, Mandarino FV. The Dual Lens of Endoscopy and Histology in the Diagnosis and Management of Eosinophilic Gastrointestinal Disorders-A Comprehensive Review. Diagnostics (Basel) 2024; 14:858. [PMID: 38667503 PMCID: PMC11049211 DOI: 10.3390/diagnostics14080858] [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: 03/12/2024] [Revised: 04/13/2024] [Accepted: 04/16/2024] [Indexed: 04/28/2024] Open
Abstract
Eosinophilic Gastrointestinal Disorders (EGIDs) are a group of conditions characterized by abnormal eosinophil accumulation in the gastrointestinal tract. Among these EGIDs, Eosinophilic Esophagitis (EoE) is the most well documented, while less is known about Eosinophilic Gastritis (EoG), Eosinophilic Enteritis (EoN), and Eosinophilic Colitis (EoC). The role of endoscopy in EGIDs is pivotal, with applications in diagnosis, disease monitoring, and therapeutic intervention. In EoE, the endoscopic reference score (EREFS) has been shown to be accurate in raising diagnostic suspicion and effective in monitoring therapeutic responses. Additionally, endoscopic dilation is the first-line treatment for esophageal strictures. For EoG and EoN, while the literature is more limited, common endoscopic findings include erythema, nodules, and ulcerations. Histology remains the gold standard for diagnosing EGIDs, as it quantifies eosinophilic infiltration. In recent years, there have been significant advancements in the histological understanding of EoE, leading to the development of diagnostic scores and the identification of specific microscopic features associated with the disease. However, for EoG, EoN, and EoC, precise eosinophil count thresholds for diagnosis have not yet been established. This review aims to elucidate the role of endoscopy and histology in the diagnosis and management of the three main EGIDs and to analyze their strengths and limitations, their interconnection, and future research directions.
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Affiliation(s)
- Alberto Barchi
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
| | - Edoardo Vespa
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
| | - Sandro Passaretti
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
| | - Giuseppe Dell’Anna
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
| | - Ernesto Fasulo
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
| | - Mona-Rita Yacoub
- Unit of Immunology, Rheumatology, Allergy and Rare Diseases, IRCCS Ospedale San Raffaele, 20132 Milan, Italy;
| | - Luca Albarello
- Pathology Unit, IRCCS Ospedale San Raffaele, 20132 Milan, Italy;
| | - Emanuele Sinagra
- Gastroenterology and Endoscopy Unit, Fondazione Istituto S. Raffaele—G. Giglio, 90015 Cefalu, Italy;
| | - Luca Massimino
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
| | - Federica Ungaro
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
| | - Silvio Danese
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
- Faculty of Medicine, Università Vita-Salute San Raffaele, 20132 Milan, Italy
| | - Francesco Vito Mandarino
- Gastroenterology and Digestive Endoscopy, IRCCS Ospedale San Raffaele, Via Olgettina 58, 20132 Milan, Italy; (A.B.); (E.V.); (S.P.); (G.D.); (E.F.); (L.M.); (F.U.); (S.D.)
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Marasco G, Visaggi P, Vassallo M, Fiocca M, Cremon C, Barbaro MR, De Bortoli N, Bellini M, Stanghellini V, Savarino EV, Barbara G. Current and Novel Therapies for Eosinophilic Gastrointestinal Diseases. Int J Mol Sci 2023; 24:15165. [PMID: 37894846 PMCID: PMC10607071 DOI: 10.3390/ijms242015165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 10/01/2023] [Accepted: 10/02/2023] [Indexed: 10/29/2023] Open
Abstract
Eosinophilic gastrointestinal diseases (EGIDs) are an emerging group of pathological entities characterized by an eosinophil-predominant infiltration of different tracts of the gut in the absence of secondary causes of eosinophilia. According to the specific tract of the gut involved, EGIDs can be classified into eosinophilic esophagitis (EoE), eosinophilic gastritis (EoG), eosinophilic enteritis (EoN), and eosinophilic colitis (EoC). The epidemiology of EGIDs is evolving rapidly. EoE, once considered a rare disease, now has an incidence and prevalence of 7.7 new cases per 100,000 inhabitants per years and 34.4 cases per 100,000 inhabitants per year, respectively. Fewer data are available regarding non-EoE EGIDs, whose prevalence are estimated to range between 2.1 and 17.6 in 100,000 individuals, depending on age, sex, and ethnicity. Diagnosis requires the presence of suggestive symptoms, endoscopic biopsies showing abnormal values of eosinophils infiltrating the gut, and exclusion of secondary causes of eosinophilia. EoE typically presents with dysphagia and episodes of food bolus impactions, while EoG, EoN, and EoC may all present with abdominal pain and diarrhea, with or without other non-specific symptoms. In addition, although different EGIDs are currently classified as different entities, there may be overlap between different diseases in the same patient. Despite EGIDs being relatively novel pathological entities, the research on possible treatments is rapidly growing. In this regard, several randomized controlled trials are currently ongoing to investigate novel molecules, including ad-hoc steroid formulations, immunosuppressants, and mostly monoclonal antibodies that target the specific molecular mediators of EGIDs. This narrative review provides an up-to-date overview of available and investigational drugs for different EGIDs.
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Affiliation(s)
- Giovanni Marasco
- IRCCS Azienda Ospedaliero, Universitaria di Bologna, Via Massarenti 9, 40138 Bologna, Italy; (G.M.); (M.V.); (M.F.); (C.C.); (M.R.B.); (V.S.)
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy
| | - Pierfrancesco Visaggi
- Gastroenterology Unit, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Risorgimento 36, 56126 Pisa, Italy; (P.V.); (N.D.B.); (M.B.)
| | - Mariagiulia Vassallo
- IRCCS Azienda Ospedaliero, Universitaria di Bologna, Via Massarenti 9, 40138 Bologna, Italy; (G.M.); (M.V.); (M.F.); (C.C.); (M.R.B.); (V.S.)
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy
| | - Miriam Fiocca
- IRCCS Azienda Ospedaliero, Universitaria di Bologna, Via Massarenti 9, 40138 Bologna, Italy; (G.M.); (M.V.); (M.F.); (C.C.); (M.R.B.); (V.S.)
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy
| | - Cesare Cremon
- IRCCS Azienda Ospedaliero, Universitaria di Bologna, Via Massarenti 9, 40138 Bologna, Italy; (G.M.); (M.V.); (M.F.); (C.C.); (M.R.B.); (V.S.)
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy
| | - Maria Raffaella Barbaro
- IRCCS Azienda Ospedaliero, Universitaria di Bologna, Via Massarenti 9, 40138 Bologna, Italy; (G.M.); (M.V.); (M.F.); (C.C.); (M.R.B.); (V.S.)
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy
| | - Nicola De Bortoli
- Gastroenterology Unit, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Risorgimento 36, 56126 Pisa, Italy; (P.V.); (N.D.B.); (M.B.)
| | - Massimo Bellini
- Gastroenterology Unit, Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Via Risorgimento 36, 56126 Pisa, Italy; (P.V.); (N.D.B.); (M.B.)
| | - Vincenzo Stanghellini
- IRCCS Azienda Ospedaliero, Universitaria di Bologna, Via Massarenti 9, 40138 Bologna, Italy; (G.M.); (M.V.); (M.F.); (C.C.); (M.R.B.); (V.S.)
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy
| | - Edoardo Vincenzo Savarino
- Gastroenterology Unit, Azienda Ospedale Università of Padua, Via Giustiniani 2, 35128 Padua, Italy;
- Department of Surgery, Oncology and Gastroenterology, University of Padua, Via Giustiniani 2, 35128 Padua, Italy
| | - Giovanni Barbara
- IRCCS Azienda Ospedaliero, Universitaria di Bologna, Via Massarenti 9, 40138 Bologna, Italy; (G.M.); (M.V.); (M.F.); (C.C.); (M.R.B.); (V.S.)
- Department of Medical and Surgical Sciences, University of Bologna, Via Massarenti, 9, 40138 Bologna, Italy
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Bochner BS, O'Sullivan JA, Chang AT, Youngblood BA. Siglecs in allergy and asthma. Mol Aspects Med 2023; 90:101104. [PMID: 35835621 PMCID: PMC10757266 DOI: 10.1016/j.mam.2022.101104] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2022] [Revised: 06/28/2022] [Accepted: 07/03/2022] [Indexed: 01/21/2023]
Abstract
The term "allergic diseases" encompasses several common, IgE-mediated conditions that range from being annoying to those that are life-threatening. Available treatments include active avoidance of the instigating allergen and the use of a variety of oral, inhaled, intranasal, intraocular and injected agents. While most individuals with allergies do well with existing therapies, there are still unmet therapeutic needs. Siglecs (sialic acid-binding, immunoglobulin-like lectins) are a family of single-pass transmembrane I-type lectins found on various subsets of cells, especially those of the immune system. All Siglecs have extracellular domains recognizing sialoside ligands, and most contain cytoplasmic domains with inhibitory signaling activity. This review focuses on Siglecs that likely play a role in regulating allergic and asthmatic responses, and how specific Siglecs, expressed on cells such as eosinophils and mast cells, are being targeted for therapeutic benefit.
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Affiliation(s)
- Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
| | - Jeremy A O'Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
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Westermann S, Dietschmann A, Doehler D, Castiglione K, Bochner BS, Voehringer D, Radtke D. Siglec-F Promotes IL-33-Induced Cytokine Release from Bone Marrow-Derived Eosinophils Independently of the ITIM and ITIM-like Motif Phosphorylation. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2022; 208:732-744. [PMID: 34996839 DOI: 10.4049/jimmunol.2100184] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 11/19/2021] [Indexed: 12/15/2022]
Abstract
Eosinophils are potent innate effector cells associated mainly with type 2 immune responses elicited by helminths and allergens. Their activity needs to be tightly controlled to prevent severe inflammation and tissue damage. Eosinophil degranulation and secretion of inflammatory effector molecules, including cytokines, chemokines, and lipid mediators, can be regulated by activating and inhibitory receptors on the cell surface. In this study, we investigated the modulation of proliferation, apoptosis, gene expression, and cytokine/chemokine secretion from IL-33-activated Mus musculus eosinophils on cross-linking of the transmembrane receptor Sialic acid-binding Ig-like lectin F (Siglec-F). Siglec-F contains an ITIM plus an ITIM-like motif in its intracellular tail and is mainly regarded as an inhibitory and apoptosis-inducing receptor. In vitro costimulation of bone marrow-derived eosinophils with anti-Siglec-F and IL-33 compared with treatment with either alone led to enhanced STAT6 phosphorylation, stronger induction of hypoxia/glycolysis-related proinflammatory genes, and elevated secretion of type 2 cytokines (IL-4, IL-13) and chemokines (CCL3, CCL4) with only minor effects on proliferation and apoptosis. Using a competitive mixed bone marrow chimera approach with wild-type and Siglec-F-deficient eosinophils, we observed no evidence for Siglec-F-regulated inhibition of Aspergillus fumigatus-elicited lung eosinophilia. Truncation of the Siglec-F cytoplasmic tail, but not mutation of the ITIM and ITIM-like motifs, ablated the effect of enhanced cytokine/chemokine secretion. This provides evidence for an ITIM phosphorylation-independent signaling pathway from the cytoplasmic tail of the Siglec-F receptor that enhances effector molecule release from activated eosinophils.
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Affiliation(s)
- Stefanie Westermann
- Department of Infection Biology, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany; and
| | - Axel Dietschmann
- Department of Infection Biology, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany; and
| | - Daniela Doehler
- Department of Infection Biology, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany; and
| | - Kirstin Castiglione
- Department of Infection Biology, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany; and
| | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - David Voehringer
- Department of Infection Biology, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany; and
| | - Daniel Radtke
- Department of Infection Biology, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany; and
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Pagovich OE, Stiles KM, Camilleri AE, Russo AR, Nag S, Crystal RG. Gene therapy in a murine model of chronic eosinophilic leukemia-not otherwise specified (CEL-NOS). Leukemia 2022; 36:525-531. [PMID: 34545183 DOI: 10.1038/s41375-021-01400-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 05/15/2021] [Accepted: 08/23/2021] [Indexed: 02/08/2023]
Abstract
Chronic eosinophilic leukemia-not otherwise specified (CEL-NOS) is a rare, aggressive, fatal disease characterized by blood eosinophilia and dysfunction of organs infiltrated with eosinophils. Clinically, the disease manifests with weight loss, cough, weakness, diarrhea, and multi-organ dysfunction that is unresponsive to therapy. We developed a one-time gene therapy for CEL-NOS using an adeno-associated virus (AAV) expressing an anti-eosinophil monoclonal antibody (AAVrh.10mAnti-Eos) to provide sustained suppression of eosinophil numbers in blood, thus reducing eosinophil tissue invasion and organ dysfunction. A novel CEL-NOS model was developed in NOD-scid IL2rγnull (NSG) mice by administration of AAV expressing the cytokine IL5 (AAVrh.10mIL5), resulting in marked peripheral and tissue eosinophilia of the heart, lung, liver, and spleen, and eventually death. Mice were administered AAVrh.10mAnti-Eos (1011 genome copies) 4 wk after administration of AAVrh.10mIL5 and evaluated for anti-eosinophil antibody expression, blood eosinophil counts, organ eosinophil invasion, and survival. AAVrh.10mAnti-Eos expressed persistent levels of the anti-eosinophil antibody for >24 wk. Strikingly, CEL-NOS treated mice had markedly lower blood eosinophil levels and reduced mortality when compared with control treated mice. These results suggest that a single treatment with AAVrh.10mAnti-Eos has the potential to provide substantial therapeutic benefit to patients with CEL-NOS, a fatal malignant disorder.
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Affiliation(s)
- Odelya E Pagovich
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Katie M Stiles
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Anna E Camilleri
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Anthony R Russo
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Saparja Nag
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA
| | - Ronald G Crystal
- Department of Genetic Medicine, Weill Cornell Medical College, New York, NY, USA.
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Camilleri AE, Nag S, Russo AR, Stiles KM, Crystal RG, Pagovich OE. Gene therapy for a murine model of eosinophilic esophagitis. Allergy 2021; 76:2740-2752. [PMID: 33748982 DOI: 10.1111/all.14822] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/05/2021] [Accepted: 01/15/2021] [Indexed: 01/07/2023]
Abstract
BACKGROUND Eosinophils are specialized granulocytic effector cells that store and release highly active mediators used in immune defense. Eosinophils are also implicated in the pathogenesis of allergic disorders, including eosinophilic esophagitis (EoE), a chronic disorder characterized by infiltration of eosinophils into the esophagus and release of mediators that damage tissue, resulting in gastrointestinal morbidity, food impaction, and dysphagia. Treatment with elimination diets and/or topical corticosteroid therapy slow disease progression, but are complicated by adverse effects, limited compliance, and loss of response to therapy. We hypothesized that a single administration of an adeno-associated virus (AAV) coding for an anti-eosinophil monoclonal antibody that induces eosinophil clearance (anti-Siglec-F) would treat on a persistent basis a murine model of EoE. METHODS A mouse model of peanut-induced EoE that mimics the human disease was established by sensitization and challenge with peanut extract. After challenge, these mice exhibited an EoE phenotype demonstrated by elevated levels of blood eosinophils, infiltration of eosinophils in the esophagus with associated esophageal remodeling and food impaction. RESULTS The mice were treated with a single intravenous administration (1011 genome copies) of AAVrh.10mAnti-Eos, a serotype rh.10 AAV vector coding for an anti-Siglec-F monoclonal antibody. Vector administration resulted in persistent, high levels of anti-Siglec-F antibody expression. Administration of AAVrh.10mAnti-Eos to the mouse model of EoE reduced blood (P < 0.02) and esophageal eosinophil numbers (P < 0.002) protected from esophageal tissue remodeling and minimized food impaction. CONCLUSION These results suggest that a single treatment with AAVrh.10mAnti-Eos has the potential to provide persistent therapeutic benefit to patients with EoE.
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Affiliation(s)
- Anna E. Camilleri
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Saparja Nag
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Anthony R. Russo
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Katie M. Stiles
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Ronald G. Crystal
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
| | - Odelya E. Pagovich
- Department of Genetic Medicine Weill Cornell Medical College New York NY USA
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Strategies for Mast Cell Inhibition in Food Allergy. THE YALE JOURNAL OF BIOLOGY AND MEDICINE 2020; 93:719-731. [PMID: 33380934 PMCID: PMC7757070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Mast cells are tissue resident allergic effector cells that drive IgE-mediated food allergies. There are several steps leading to mast cell activation in the context of allergic disease that can be targeted to prevent mast cell activation and degranulation. These include blocking IgE-FcεRI crosslinking and type 2 cytokine receptor activation; modulating cell-surface neural chemical receptors; stabilizing mast cell membranes to prevent co-localization of activating receptors; impeding intracellular signaling; and engaging cell surface inhibitory receptors. This review highlights several ITIM-containing inhibitory mast cell surface receptors that could serve as pharmaceutical targets to prevent mast cell activation and degranulation in the context of food allergy. When activated, these ITIM-containing inhibitory receptors recruit the phosphatases SHP-1, SHP-2, and/or SHIP to dephosphorylate the tyrosine kinases responsible for activation signals downstream of the IgE-FcεRI complex. We describe several members of the Ig and Ig-like inhibitory receptor and C-type lectin inhibitory receptor superfamilies. Fundamental studies exploring the behavior of these receptors within the context of experimental food allergy models are needed. A deeper understanding of how these receptors modulate mast cell-driven food allergic responses will shape future strategies to harness these inhibitory receptors to treat food allergy.
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Discovery, Function, and Therapeutic Targeting of Siglec-8. Cells 2020; 10:cells10010019. [PMID: 33374255 PMCID: PMC7823959 DOI: 10.3390/cells10010019] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/18/2020] [Accepted: 12/20/2020] [Indexed: 12/11/2022] Open
Abstract
Siglecs (sialic acid-binding immunoglobulin-like lectins) are single-pass cell surface receptors that have inhibitory activities on immune cells. Among these, Siglec-8 is a CD33-related family member selectively expressed on human mast cells and eosinophils, and at low levels on basophils. These cells can participate in inflammatory responses by releasing mediators that attract or activate other cells, contributing to the pathogenesis of allergic and non-allergic diseases. Since its discovery in 2000, initial in vitro studies have found that the engagement of Siglec-8 with a monoclonal antibody or with selective polyvalent sialoglycan ligands induced the cell death of eosinophils and inhibited mast cell degranulation. Anti-Siglec-8 antibody administration in vivo to humanized and transgenic mice selectively expressing Siglec-8 on mouse eosinophils and mast cells confirmed the in vitro findings, and identified additional anti-inflammatory effects. AK002 (lirentelimab) is a humanized non-fucosylated IgG1 antibody against Siglec-8 in clinical development for mast cell- and eosinophil-mediated diseases. AK002 administration has safely demonstrated the inhibition of mast cell activity and the depletion of eosinophils in several phase 1 and phase 2 trials. This article reviews the discovery and functions of Siglec-8, and strategies for its therapeutic targeting for the treatment of eosinophil- and mast cell-associated diseases.
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Knuplez E, Krier-Burris R, Cao Y, Marsche G, O’Sullivan J, Bochner BS. Frontline Science: Superior mouse eosinophil depletion in vivo targeting transgenic Siglec-8 instead of endogenous Siglec-F: Mechanisms and pitfalls. J Leukoc Biol 2020; 108:43-58. [PMID: 32134149 PMCID: PMC7585130 DOI: 10.1002/jlb.3hi0120-381r] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 01/30/2020] [Accepted: 02/05/2020] [Indexed: 01/02/2023] Open
Abstract
Eosinophils are important multifunctional granulocytes. When studying eosinophil function and its contribution to diseases, mouse models are often used. Mouse eosinophils selectively express sialic acid-binding immunoglobulin-like lectin (Siglec)-F. Its closest functional paralog on human eosinophils is Siglec-8. These Siglecs are being used to target eosinophils when exploring their mechanistic roles in disease and for potential therapeutic benefit. In order to facilitate preclinical studies of human Siglec-8, we developed transgenic mouse strains expressing human Siglec-8 only on the surface of eosinophils with or without endogenous Siglec-F and have begun characterizing various cellular functions in vitro and in vivo. Eosinophils from Siglec-8+ mice, with or without Siglec-F, responded to Siglec-8 antibody engagement in vitro by up-regulating surface CD11b, whereas Siglec-F antibody had no such effect. Engagement of Siglec-F or Siglec-8 with respective antibodies in vitro resulted in only modest increases in cell death. Administration of rat Siglec-F antibodies to mice led to a significant decrease in Siglec-F surface expression on eosinophils due to internalization, and thus appeared to decrease eosinophil numbers based on Siglec-F+ cells, but with proper gaiting strategies did not in fact result in significant eosinophil depletion. In marked contrast, administration of mouse Siglec-8 antibodies rapidly and effectively depleted eosinophils from blood and spleens of mice, but an F(ab')2 version did not, indicating an Fc-mediated mechanism for eosinophil depletion in vivo. Siglec-8 expressing mice with or without endogenous Siglec-F will be useful to study Siglec-8-based therapeutics, and may be a preferred approach when acute or chronic eosinophil depletion is needed.
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Affiliation(s)
- Eva Knuplez
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Austria
| | - Rebecca Krier-Burris
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yun Cao
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Gunther Marsche
- Division of Pharmacology, Otto Loewi Research Center, Medical University of Graz, Austria
| | - Jeremy O’Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Bruce S. Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Läubli H, Varki A. Sialic acid-binding immunoglobulin-like lectins (Siglecs) detect self-associated molecular patterns to regulate immune responses. Cell Mol Life Sci 2020; 77:593-605. [PMID: 31485715 PMCID: PMC7942692 DOI: 10.1007/s00018-019-03288-x] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 08/11/2019] [Accepted: 08/28/2019] [Indexed: 12/12/2022]
Abstract
The mammalian immune system evolved to tightly regulate the elimination of pathogenic microbes and neoplastic transformed cells while tolerating our own healthy cells. Here, we summarize experimental evidence for the role of Siglecs-in particular CD33-related Siglecs-as self-receptors and their sialoglycan ligands in regulating this balance between recognition of self and non-self. Sialoglycans are found in the glycocalyx and extracellular fluids and matrices of all mammalian cells and can be considered as self-associated molecular patterns (SAMPs). We also provide an overview of the known interactions of Siglec receptors and sialoglycan-SAMPs. Manipulation of the Siglec-SAMP axis offers new therapeutic opportunities for the treatment of inflammatory conditions, autoimmune diseases and also cancer immunotherapy.
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Affiliation(s)
- Heinz Läubli
- Laboratory for Cancer Immunotherapy, University Hospital Basel, Petersgraben 4, 4031, Basel, Switzerland.
| | - Ajit Varki
- Department of Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, 92093-0687, USA.
- Department of Cellular and Molecular Medicine, Glycobiology Research and Training Center, University of California, San Diego, La Jolla, CA, 92093-0687, USA.
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11
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Future therapies for eosinophilic gastrointestinal disorders. Ann Allergy Asthma Immunol 2019; 124:219-226. [PMID: 31778820 DOI: 10.1016/j.anai.2019.11.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Revised: 11/13/2019] [Accepted: 11/14/2019] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To review novel therapeutics in development for treatment of eosinophilic gastrointestinal disorders (EGIDs). DATA SOURCES Clinical trial data (clinicaltrials.gov) and literature search on PubMed. STUDY SELECTIONS Studies on treatment and clinical trials in EGIDs were included in this review. RESULTS During the past decade, significant progress has been made in understanding disease mechanisms in EGIDs. As a result, a variety of novel therapeutics have been developed for treatment of these disorders. Several monoclonal antibodies against targets, including interleukin (IL) 4, IL-5, IL-13, integrins, and siglec-8, have shown promise in early trials. Novel formulations of corticosteroids are also in development. CONCLUSION The field of EGID research has advanced rapidly, and disease-modifying therapeutics are closer to clinical application.
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12
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Youngblood BA, Brock EC, Leung J, Falahati R, Bochner BS, Rasmussen HS, Peterson K, Bebbington C, Tomasevic N. Siglec-8 antibody reduces eosinophils and mast cells in a transgenic mouse model of eosinophilic gastroenteritis. JCI Insight 2019; 4:126219. [PMID: 31465299 DOI: 10.1172/jci.insight.126219] [Citation(s) in RCA: 78] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 08/23/2019] [Indexed: 01/18/2023] Open
Abstract
Aberrant accumulation and activation of eosinophils and potentially mast cells (MCs) contribute to the pathogenesis of eosinophilic gastrointestinal diseases (EGIDs), including eosinophilic esophagitis (EoE), gastritis (EG), and gastroenteritis (EGE). Current treatment options, such as diet restriction and corticosteroids, have limited efficacy and are often inappropriate for chronic use. One promising new approach is to deplete eosinophils and inhibit MCs with a monoclonal antibody (mAb) against sialic acid-binding immunoglobulin-like lectin 8 (Siglec-8), an inhibitory receptor selectively expressed on MCs and eosinophils. Here, we characterize MCs and eosinophils from human EG and EoE biopsies using flow cytometry and evaluate the effects of an anti-Siglec-8 mAb using a potentially novel Siglec-8-transgenic mouse model in which EG/EGE was induced by ovalbumin sensitization and intragastric challenge. MCs and eosinophils were significantly increased and activated in human EG and EoE biopsies compared with healthy controls. Similar observations were made in EG/EGE mice. In Siglec-8-transgenic mice, anti-Siglec-8 mAb administration significantly reduced eosinophils and MCs in the stomach, small intestine, and mesenteric lymph nodes and decreased levels of inflammatory mediators. In summary, these findings suggest a role for both MCs and eosinophils in EGID pathogenesis and support the evaluation of anti-Siglec-8 as a therapeutic approach that targets both eosinophils and MCs.
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Affiliation(s)
| | | | - John Leung
- Allakos, Inc., Redwood City, California, USA
| | | | - Bruce S Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | | | - Kathryn Peterson
- Division of Gastroenterology, Department of Medicine, University of Utah Health Sciences Center, Salt Lake City, Utah, USA
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13
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O’Sullivan JA, Wei Y, Carroll DJ, Moreno-Vinasco L, Cao Y, Zhang F, Lee JJ, Zhu Z, Bochner BS. Frontline Science: Characterization of a novel mouse strain expressing human Siglec-8 only on eosinophils. J Leukoc Biol 2018; 104:11-19. [PMID: 29601103 PMCID: PMC6013361 DOI: 10.1002/jlb.2hi0917-391r] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 02/08/2018] [Accepted: 02/12/2018] [Indexed: 01/01/2023] Open
Abstract
Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is a human cell surface protein expressed exclusively on eosinophils, mast cells, and basophils that, when engaged, induces eosinophil apoptosis and inhibits mast cell mediator release. This makes Siglec-8 a promising therapeutic target to treat diseases involving these cell types. However, preclinical studies of Siglec-8 targeting in vivo are lacking because this protein is only found in humans, apes, and some monkeys. Therefore, we have developed a mouse strain in which SIGLEC8 transcription is activated by Cre recombinase and have crossed this mouse with the eoCre mouse to achieve eosinophil-specific expression. We confirmed that Siglec-8 is expressed exclusively on the surface of mature eosinophils in multiple tissues at levels comparable to those on human blood eosinophils. Following ovalbumin sensitization and airway challenge, Siglec-8 knock-in mice generated a pattern of allergic lung inflammation indistinguishable from that of littermate controls, suggesting that Siglec-8 expression within the eosinophil compartment does not alter allergic eosinophilic inflammation. Using bone marrow from these mice, we demonstrated that, during maturation, Siglec-8 expression occurs well before the late eosinophil developmental marker C-C motif chemokine receptor 3, consistent with eoCre expression. Antibody ligation of the receptor induces Siglec-8 endocytosis and alters the phosphotyrosine profile of these cells, indicative of productive signaling. Finally, we demonstrated that mouse eosinophils expressing Siglec-8 undergo cell death when the receptor is engaged, further evidence that Siglec-8 is functional on these cells. These mice should prove useful to investigate Siglec-8 biology and targeting in vivo in a variety of eosinophilic disease models.
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Affiliation(s)
- Jeremy A. O’Sullivan
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yadong Wei
- Section of Allergy and Clinical Immunology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Daniela J. Carroll
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Liliana Moreno-Vinasco
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Yun Cao
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Fengrui Zhang
- Section of Allergy and Clinical Immunology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - James. J. Lee
- Division of Pulmonary Medicine, Department of Biochemistry and Molecular Biology, Mayo Clinic Arizona, Scottsdale, Arizona, USA
| | - Zhou Zhu
- Section of Allergy and Clinical Immunology, Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut, USA
| | - Bruce S. Bochner
- Division of Allergy and Immunology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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14
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Wu J, Zhong Y, Shen X, Yang K, Cai W. Maternal and early-life vitamin D deficiency enhances allergic reaction in an ovalbumin-sensitized BALB/c mouse model. Food Nutr Res 2018; 62:1401. [PMID: 29881333 PMCID: PMC5985744 DOI: 10.29219/fnr.v62.1401] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 12/11/2022] Open
Abstract
Background Recent studies have shown that vitamin D deficiency may contribute to the high prevalence of food allergy but the underlying mechanisms are far from clear. Objective The present study was designed to investigate the effect of maternal and early-life vitamin D deficiency in the development of food allergy. Design BALB/c mice were treated with ovalbumin (OVA) to trigger allergic reactions, under vitamin D-deficient (by maternal and early-life feeding of vitamin D deprived chow diet) or vitamin D-sufficient conditions. Results Increased occurrence and severity of allergic diarrhea as well as decreased rectal temperature were observed after OVA sensitization. For vitamin D deficiency groups, OVA-specific IgE and IL-4 levels were significantly increased, while IFN-γ levels were unchanged. Vitamin D deficiency also attenuated the structure of small intestinal villi and decreased the expression of the tight junction protein between adjacent epithelial cells and the percentages of CD4+CD25+Foxp3+Treg cell in spleen and mesenteric lymph nodes. Conclusions Maternal and early-life vitamin D deficiency have notable influence on the susceptibility to food allergy, which may relate with the reduced population of Treg cell and the dysfunction of intestinal epithelial barrier.
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Affiliation(s)
- Jiang Wu
- Department of Clinical Nutrition, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China, 200092
| | - Yan Zhong
- Department of Clinical Nutrition, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Nutrition, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xiuhua Shen
- Department of Clinical Nutrition, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Nutrition, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Kefeng Yang
- Department of Clinical Nutrition, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Nutrition, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China, 200092
| | - Wei Cai
- Department of Clinical Nutrition, Xin Hua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Department of Nutrition, Shanghai Jiao Tong University School of Medicine, Shanghai, China.,Shanghai Key Laboratory of Pediatric Gastroenterology and Nutrition, Shanghai, China, 200092
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15
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Bastan I, Ge XN, Dileepan M, Greenberg YG, Guedes AG, Hwang SH, Hammock BD, Washabau RJ, Rao SP, Sriramarao P. Inhibition of soluble epoxide hydrolase attenuates eosinophil recruitment and food allergen-induced gastrointestinal inflammation. J Leukoc Biol 2018; 104:109-122. [PMID: 29345370 DOI: 10.1002/jlb.3ma1017-423r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Revised: 12/20/2017] [Accepted: 12/21/2017] [Indexed: 12/11/2022] Open
Abstract
Prevalence of food allergies in the United States is on the rise. Eosinophils are recruited to the intestinal mucosa in substantial numbers in food allergen-driven gastrointestinal (GI) inflammation. Soluble epoxide hydrolase (sEH) is known to play a pro-inflammatory role during inflammation by metabolizing anti-inflammatory epoxyeicosatrienoic acids (EETs) to pro-inflammatory diols. We investigated the role of sEH in a murine model of food allergy and evaluated the potential therapeutic effect of a highly selective sEH inhibitor (trans-4-{4-[3-(4-trifluoromethoxyphenyl)-ureido]-cyclohexyloxy}-benzoic acid [t-TUCB]). Oral exposure of mice on a soy-free diet to soy protein isolate (SPI) induced expression of intestinal sEH, increased circulating total and antigen-specific IgE levels, and caused significant weight loss. Administration of t-TUCB to SPI-challenged mice inhibited IgE levels and prevented SPI-induced weight loss. Additionally, SPI-induced GI inflammation characterized by increased recruitment of eosinophils and mast cells, elevated eotaxin 1 levels, mucus hypersecretion, and decreased epithelial junction protein expression. In t-TUCB-treated mice, eosinophilia, mast cell recruitment, and mucus secretion were significantly lower than in untreated mice and SPI-induced loss of junction protein expression was prevented to variable levels. sEH expression in eosinophils was induced by inflammatory mediators TNF-α and eotaxin-1. Treatment of eosinophils with t-TUCB significantly inhibited eosinophil migration, an effect that was mirrored by treatment with 11,12-EET, by inhibiting intracellular signaling events such as ERK (1/2) activation and eotaxin-1-induced calcium flux. These studies suggest that sEH induced by soy proteins promotes allergic responses and GI inflammation including eosinophilia and that inhibition of sEH can attenuate these responses.
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Affiliation(s)
- Idil Bastan
- Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, Minnesota, USA
| | - Xiao Na Ge
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, USA
| | - Mythili Dileepan
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, USA
| | - Yana G Greenberg
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, USA
| | - Alonso G Guedes
- Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, Minnesota, USA
| | - Sung Hee Hwang
- Department of Entomology, Nematology and Comprehensive Cancer Center, University of California, Davis, California, USA
| | - Bruce D Hammock
- Department of Entomology, Nematology and Comprehensive Cancer Center, University of California, Davis, California, USA
| | - Robert J Washabau
- Department of Veterinary Clinical Sciences, University of Minnesota, St. Paul, Minnesota, USA
| | - Savita P Rao
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, USA
| | - P Sriramarao
- Department of Veterinary and Biomedical Sciences, University of Minnesota, St. Paul, Minnesota, USA
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16
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Abstract
PURPOSE OF REVIEW Eosinophils are a subset of granulocytes generally associated with type 2 immune responses. They can contribute to protection against helminths but also mediate pro-inflammatory functions during allergic immune responses. Only recently, eosinophils were also found to exert many other functions such as regulation of glucose and fat metabolism, thermogenesis, survival of plasma cells, and antitumor activity. The mechanisms that control eosinophil development and survival are only partially understood. RECENT FINDINGS Here we review new findings regarding the role of cell-extrinsic and cell-intrinsic factors for eosinophilopoiesis and eosinophil homeostasis. Several reports provide new insights in the regulation of eosinophil development by transcription factors, miRNAs and epigenetic modifications. Danger signals like lipopolysaccharide or alarmins can activate eosinophils but also prolong their lifespan. We further reflect on the observations that eosinophil development is tightly controlled by the unfolded protein stress response and formation of cytoplasmic granules. SUMMARY Eosinophils emerge as important regulators of diverse biological processes. Their differentiation and survival is tightly regulated by factors that are still poorly understood. Newly identified pathways involved in eosinophilopoiesis and eosinophil homeostasis may lead to development of new therapeutic options for treatment of eosinophil-associated diseases.
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17
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Zhao Y, Liu D, Zhang S, Pan L, Qin G. Different Damage to the Mechanical Barrier Function of IPEC-J2 Induced by Soybean Allergen β-conglycinin Hydrolyzed Peptides. INTERNATIONAL JOURNAL OF FOOD ENGINEERING 2017. [DOI: 10.1515/ijfe-2016-0370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
AbstractThree major enzyme-hydrolyzed peptides have been produced after simulative digestionin vitroof soybean β-conglycinin. The intestinal barrier of IPEC-J2 induced by β-conglycinin enzyme-hydrolyzed peptides was evaluated in this study. The increased alkaline phosphatase (AP) activity was actually linearly correlated with the incubation time by the hydrolysate, the purified 52 kD peptide, or the mixture of 25 and 30 kD peptides. The MTT and TEER values declined in dose-dependence (0–2 mg/mL,p\lt 0.05) or in time-dependence (2–24 h,p \lt0.05). After treatment with different hydrolyzed peptides, the tight junction expression of claudin-3, claudin-4, occludin, and ZO-1 were reduced (p\lt 0.05). Finally, it is found out that the maximum damage to the epithelial barrier function was induced by the mixture of 25 and 30 kD peptide, whereas the minimum damage was caused by the 52 kD peptide.
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18
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Song DJ, Shim MH, Lee N, Yoo Y, Choung JT. CCR3 Monoclonal Antibody Inhibits Eosinophilic Inflammation and Mucosal Injury in a Mouse Model of Eosinophilic Gastroenteritis. ALLERGY, ASTHMA & IMMUNOLOGY RESEARCH 2017; 9:360-367. [PMID: 28497923 PMCID: PMC5446951 DOI: 10.4168/aair.2017.9.4.360] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/11/2016] [Revised: 01/31/2017] [Accepted: 01/31/2017] [Indexed: 11/28/2022]
Abstract
Purpose Although the role of eosinophils in eosinophilic gastroenteritis (EGE) is not fully understood, they are believed to be a principal effector cell. Previous studies have demonstrated that eotaxin and its specific receptor, cysteine-cysteine chemokine receptor-3 (CCR3), play a central role in eosinophil trafficking into the gastrointestinal (GI) tract. Thus, we examined the targeting of CCR3 as a potential therapeutic intervention for EGE in a mouse model. Methods Eight- to 10-week-old BALB/c mice were intraperitoneally sensitized and intragastrically challenged with ovalbumin (OVA). Different groups of mice were administered either an anti-CCR3 antibody or a control IgG by intraperitoneal injection 1 hour before each OVA challenge. Eosinophilic inflammation in the intestinal mucosa, mucosal injury, and severity of diarrhea were compared between different groups at 1 hour after final OVA challenge. Results Anti-CCR3 antibody reduced the number of eosinophils in peripheral blood and intestinal mucosa, but not in bone marrow. This reduction was associated with restoration of reduced villous crypt ratio, increased intestinal epithelial cell proliferation, and weight loss induced by OVA challenge. However, Anti-CCR3 antibody had no effect on the level of OVA specific immunoglobulin E (IgE) and the expression of critical chemokines or cytokines in eosinophil trafficking into the GI tract, such as eotaxin-1, interleukin (IL)-5, and IL-13. Conclusions Anti-CCR3 antibody significantly reduced the severity of eosinophilic inflammation, mucosal injury, and diarrhea in a mouse model of food allergen-induced GI eosinophilic inflammation. CCR3 may be a novel therapeutic target for treatment of EGE and other GI eosinophil-mediated diseases.
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Affiliation(s)
- Dae Jin Song
- Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.,Environmental Health Center for Childhood Asthma, Korea University Anam Hospital, Seoul, Korea.
| | - Mun Hee Shim
- Department of Pediatrics, Korea University College of Medicine, Seoul, Korea
| | - Nahyun Lee
- Department of Pediatrics, Korea University College of Medicine, Seoul, Korea
| | - Young Yoo
- Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.,Environmental Health Center for Childhood Asthma, Korea University Anam Hospital, Seoul, Korea
| | - Ji Tae Choung
- Department of Pediatrics, Korea University College of Medicine, Seoul, Korea.,Environmental Health Center for Childhood Asthma, Korea University Anam Hospital, Seoul, Korea
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19
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Zhu X, Hogan SP, Molkentin JD, Zimmermann N. Cyclophilin D regulates necrosis, but not apoptosis, of murine eosinophils. Am J Physiol Gastrointest Liver Physiol 2016; 310:G609-17. [PMID: 26893161 PMCID: PMC4836130 DOI: 10.1152/ajpgi.00389.2015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 02/08/2016] [Indexed: 01/31/2023]
Abstract
Eosinophil degranulation and clusters of free extracellular granules are frequently observed in diverse diseases, including atopic dermatitis, nasal polyposis, and eosinophilic esophagitis. Whether these intact granules are released by necrosis or a biochemically mediated cytolysis remains unknown. Recently, a peptidyl-prolyl isomerase located within the mitochondrial matrix, cyclophilin D (PPIF), was shown to regulate necrotic, but not apoptotic, cell death in vitro in fibroblasts, hepatocytes, and cardiomyocytes. Whether cyclophilin D regulates necrosis in hematopoietic cells such as eosinophils remains unknown. We used PPIF-deficient (Ppif(-/-)) mice to test whether cyclophilin D is required for regulating eosinophil necrosis. PPIF deficiency did not affect eosinophil development or maturation at baseline. After in vitro ionomycin or H2O2 treatment, Ppif(-/-) eosinophils were significantly protected from Ca(2+) overload- or oxidative stress-induced necrosis. Additionally, Ppif(-/-) eosinophils demonstrated significantly decreased necrosis, but not apoptosis, in response to Siglec-F cross-linking, a stimulus associated with eosinophil-mediated processes in vitro and in vivo. When treated with apoptosis inducers, Ppif(+/+) and Ppif(-/-) eosinophils exhibited no significant difference in apoptosis or secondary necrosis. Finally, in a dextran sodium sulfate-induced colitis model, although levels of colitogenic cytokines and eosinophil-selective chemokines were comparable between Ppif(+/+) and Ppif(-/-) mice, the latter exhibited decreased clinical outcomes. This correlated with significantly reduced eosinophil cytolysis in the colon. Collectively, our present studies demonstrate that murine eosinophil necrosis is regulated in vitro and in vivo by cyclophilin D, at least in part, thus providing new insight into the mechanism of eosinophil necrosis and release of free extracellular granules in eosinophil-associated diseases.
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Affiliation(s)
- Xiang Zhu
- Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Simon P Hogan
- Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
| | - Jeffery D Molkentin
- Division of Molecular Cardiovascular Biology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio
| | - Nives Zimmermann
- Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, Ohio; and
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20
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Bochner BS. "Siglec"ting the allergic response for therapeutic targeting. Glycobiology 2016; 26:546-52. [PMID: 26911285 DOI: 10.1093/glycob/cww024] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 02/20/2016] [Indexed: 01/09/2023] Open
Abstract
As a physician-scientist, I have pursued research related to translational immunology with the goal of improving our ability to diagnose and treat allergic, immunologic and other diseases involving eosinophils, basophils and mast cells. We have tried to delineate novel mechanisms of human disease, working whenever possible with primary human cells and tissues, attempting to identify targets that might be amenable to the development of new therapies. As a general strategy, we have compared eosinophils, basophils, mast cells and neutrophils to look for pathways in inflammation that were unique to distinct subsets of these cells. In doing so, the concepts of glycobiology did not enter my mind until we began noticing some intriguing functional differences involving selectins and their ligands among these cell types. One simple observation, that neutrophils were coated with a glycan that allowed them to interact with an endothelial adhesion molecule while eosinophils lacked this structure, pried open the glyco-door for me. Fruitful collaborations with card-carrying glycobiologists soon followed that have forever positively influenced our science, and have enhanced our hypotheses, experimental design, research opportunities and discoveries. Within a few years, we helped to discover Siglec-8, an I-type lectin expressed only on human eosinophils, basophils, mast cells. This receptor, together with its closest mouse counterpart Siglec-F, has been the primary focus of our work now for over a decade. If not for those in the fields of glycobiology and glycoimmunology, my lab would not have made much progress toward the goal of leveraging Siglec-8 for therapeutic purposes.
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Affiliation(s)
- Bruce S Bochner
- Department of Medicine, Division of Allergy-Immunology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA
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21
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Nakamura R, Takanezawa Y, Sone Y, Uraguchi S, Sakabe K, Kiyono M. Immunotoxic Effect of Low-Dose Methylmercury Is Negligible in Mouse Models of Ovalbumin or Mite-Induced Th2 Allergy. Biol Pharm Bull 2016; 39:1353-8. [DOI: 10.1248/bpb.b16-00306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Ryosuke Nakamura
- Department of Public Health, School of Pharmacy, Kitasato University
| | | | - Yuka Sone
- Department of Public Health, School of Pharmacy, Kitasato University
| | - Shimpei Uraguchi
- Department of Public Health, School of Pharmacy, Kitasato University
| | - Kou Sakabe
- Department of Human Structure and Function, Tokai University School of Medicine
| | - Masako Kiyono
- Department of Public Health, School of Pharmacy, Kitasato University
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22
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Feeding probiotic Lactobacillus rhamnosus (MTCC 5897) fermented milk to suckling mothers alleviates ovalbumin-induced allergic sensitisation in mice offspring. Br J Nutr 2015; 114:1168-79. [PMID: 26330132 DOI: 10.1017/s000711451500286x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The neonatal period is often polarised to T helper (Th2) response at the time of birth, predisposing offspring to allergic disorders. Passive immunity through the mother's milk is critical for immune system development of newborns. Probiotics have been proposed to harmonise Th1/Th2 imbalance in allergic conditions in adults. In the present study, the anti-allergic effects of feeding probiotic Lactobacillus rhamnosus-fermented milk (PFM) either to dams during the suckling period or to their offspring after weaning individually or else in successive periods against ovalbumin (OVA)-induced allergy in newborns was analysed. After allergen sensitisation, physical symptoms of allergy, gut immune response, humoral immune response and cell-mediated response through interleukins were detected. Consumption of PFM by mothers and offspring showed a reduction (P<0·01) in physical allergic symptoms in newborns with an increase (P<0·01) in the numbers of goblet and IgA+ cells in the small intestine. Similarly, considerable (P<0·001) decreases in OVA-specific antibodies (IgE, IgG, IgG1) and ratios of IgE/IgG2a and IgG1/IgG2a in the sera of newborn mice were recorded. A decrease in IL-4 and an increase in interferon-γ levels further confirmed the shift from Th2 to Th1 pathway in PFM-fed mice. It is logical to conclude that the timing of PFM intervention in alleviating allergic symptoms is critical, which was found to be most effective when mothers were fed during the suckling period.
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In Vitro and In Vivo Cytogenotoxic Effects of Hot Aqueous Extract of Achyrocline satureioides (Lam.) DC. BIOMED RESEARCH INTERNATIONAL 2015; 2015:270973. [PMID: 26078941 PMCID: PMC4442415 DOI: 10.1155/2015/270973] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/26/2014] [Revised: 02/01/2015] [Accepted: 02/01/2015] [Indexed: 11/17/2022]
Abstract
In this work we extend the toxicological studies of hot aqueous extract of A. satureioides (As-HAE) evaluating cytotoxic and apoptotic effects on human peripheral blood mononuclear cells (PBMCs). We also determine genotoxic action of this extract in vivo. In addition, the extract was chemically characterized. Finally, we established a comparison with previous data of cold aqueous extract. The As-HAE induced cytotoxicity on PBMCs determined by trypan blue dye exclusion (CC50 = 653 μg/mL) and MTT (CC50 = 588 μg/mL) assays being more toxic than cold extract. However, As-HAE as well as cold extract did not induce apoptosis measured by Hoechst 33258 staining, TUNEL assay, and DNA fragmentation analysis. The in vivo micronucleus test showed that As-HAE exerted cytogenotoxic effects on bone marrow of mice, contrary to what was observed with cold extract. The chemical study of As-HAE allowed identifying the flavonoids found in cold extract: luteolin, quercetin, and 3-O-methylquercetin, but at higher concentrations. We suggest that toxic effects induced by As-HAE could be due to high concentrations of these flavonoids. Given that As-HAE is the most used in folkloric medicine, its administration should be controlled in order to prevent potential cell damage.
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Zhao Y, Liu D, Han R, Zhang X, Zhang S, Qin G. Soybean allergen glycinin induced the destruction of the mechanical barrier function in IPEC-J2. FOOD AGR IMMUNOL 2015. [DOI: 10.1080/09540105.2014.998638] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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Bochner BS, Zimmermann N. Role of siglecs and related glycan-binding proteins in immune responses and immunoregulation. J Allergy Clin Immunol 2015; 135:598-608. [PMID: 25592986 DOI: 10.1016/j.jaci.2014.11.031] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/14/2014] [Accepted: 11/25/2014] [Indexed: 12/16/2022]
Abstract
Virtually all cells and extracellular material are heavily decorated by various glycans, yet our understanding of the structure and function of these moieties lags behind the understanding of nucleic acids, lipids, and proteins. Recent years have seen a tremendous acceleration of knowledge in the field of glycobiology, revealing many intricacies and functional contributions that were previously poorly appreciated or even unrecognized. This review highlights several topics relevant to glycoimmunology in which mammalian and pathogen-derived glycans displayed on glycoproteins and other scaffolds are recognized by specific glycan-binding proteins (GBPs), leading to a variety of proinflammatory and anti-inflammatory cellular responses. The focus for this review is mainly on 2 families of GBPs, sialic acid-binding immunoglobulin-like lectins (siglecs) and selectins, that are involved in multiple steps of the immune response, including distinguishing pathogens from self, cell trafficking to sites of inflammation, fine-tuning of immune responses leading to activation or tolerance, and regulation of cell survival. Importantly for the clinician, accelerated rates of discovery in the field of glycoimmunology are being translated into innovative medical approaches that harness the interaction of glycans and GBPs to the benefit of the host and might soon lead to novel diagnostics and therapeutics.
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Affiliation(s)
- Bruce S Bochner
- Department of Medicine, Division of Allergy-Immunology, Northwestern University Feinberg School of Medicine, Chicago, Ill.
| | - Nives Zimmermann
- Department of Pediatrics, Division of Allergy and Immunology, Children's Hospital Medical Center, and Department of Pathology, University of Cincinnati College of Medicine, Cincinnati, Ohio
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Additive anti-allergic effects of anti-interleukin-33 and anti-Siglec-F treatments in a murine model of allergic asthma. Cent Eur J Immunol 2014; 39:426-33. [PMID: 26155158 PMCID: PMC4439951 DOI: 10.5114/ceji.2014.47724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Accepted: 09/24/2014] [Indexed: 12/21/2022] Open
Abstract
Background Anti-interleukin-33 (anti-IL-33) and anti-Siglec-F antibodies have potent anti-allergic effects on murine allergic asthma and rhinitis and induce eosinophil apoptosis. Objective We aimed to determine whether post-sensitization with anti-IL-33/anti-Siglec-F treatments exhibited more potent effects compared to individual treatments in a murine allergic asthma model. Material and methods Twenty-five BALB/c mice were separated into five groups (n = 5): Group A (control), Group B (ovalbumin [OVA] challenge), Group C (OVA + anti-IL-33), Group D (OVA + anti-Siglec-F), and Group E (OVA + anti-IL-33 + anti-Siglec-F). Serum total/ OVA-specific IgE, bronchoalveolar lavage (BAL) inflammatory cells and cytokines (IL-4 and IL-5), histopathological lung properties, and airway hyperreactivity were compared. Results Ovalbumin challenge induced strong immune and inflammatory responses with > 6-fold IgE level increases; 10- to 25-fold BAL eosinophil, neutrophil, and lymphocyte count increases; and > 1.5-fold IL-4 and IL-5 level increases (p < 0.05). Whereas anti-IL-33 reduced neutrophil counts, anti-Siglec-F and anti-IL-33/anti-Siglec-F reduced both eosinophil and neutrophil counts (p < 0.05). Individual treatments reduced OVA-mediated bronchiolar infiltration by 50% (p <0.05). Ovalbumin challenge increased airway hyperreactivity by 4-fold (Group B; 2000.0 ±671.8% increase in Penh) compared to controls (Group A; 445.7 ±33.5% increase in Penh) (p = 0.016). The anti-IL-33 (Group C: 1579.4 ±973.6% increase in Penh) and anti-Siglec-F (Group D: 930.4 ±236.5%) groups demonstrated significantly reduced hyperreactivity (p = 0.029). Anti-IL-33/anti-Siglec-F therapy showed synergism towards neutrophil counts, IL-5 concentrations, bronchial infiltration, and hyperreactivity (p < 0.05). Conclusions Combination treatment with anti-IL-33/anti-Siglec-F had more potent anti-allergic effects, reducing eosinophilic infiltration through their additive effects in a murine allergic asthma model.
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Zhao Y, Qin G, Han R, Wang J, Zhang X, Liu D. β-Conglycinin reduces the tight junction occludin and ZO-1 expression in IPEC-J2. Int J Mol Sci 2014; 15:1915-26. [PMID: 24473141 PMCID: PMC3958829 DOI: 10.3390/ijms15021915] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2013] [Revised: 01/12/2014] [Accepted: 01/20/2014] [Indexed: 12/21/2022] Open
Abstract
Soybean allergy presents a health threat to humans and animals. The mechanism by which food/feed allergen β-conglycinin injures the intestinal barrier has not been well understood. In this study, the changes of epithelial permeability, integrity, metabolic activity, the tight junction (TJ) distribution and expression induced by β-conglycinin were evaluated using IPEC-J2 model. The results showed a significant decrease of trans-epithelial electrical resistance (TEER) (p < 0.001) and metabolic activity (p < 0.001) and a remarkable increase of alkaline phosphatase (AP) activity (p < 0.001) in a dose-dependent manner. The expression levels of tight junction occludin and ZO-1 were decreased (p < 0.05). The reduced fluorescence of targets and change of cellular morphology were recorded. The tight junction occludin and ZO-1 mRNA expression linearly declined with increasing β-conglycinin (p < 0.001).
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Affiliation(s)
- Yuan Zhao
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Guixin Qin
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Rui Han
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Jun Wang
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
| | - Xiaodong Zhang
- Key Laboratory of Zoonosis Research, Ministry of Education, Institute of Zoonosis, College of Veterinary Medicine, Jilin University, Changchun 130062, China.
| | - Dandan Liu
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China.
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Kim YH, Park CS, Lim DH, Son BK, Kim JH, Ahn SH, Bochner BS, Na K, Jang TY. Antiallergic effect of anti-Siglec-F through reduction of eosinophilic inflammation in murine allergic rhinitis. Am J Rhinol Allergy 2013; 27:187-91. [PMID: 23710953 DOI: 10.2500/ajra.2013.27.3866] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Sialic acid-binding Ig-like lectin-F (Siglec-F) in mice and its functional paralog Siglec-8 in humans are transmembrane receptors that play a role in the apoptosis of eosinophils. We aimed to evaluate the therapeutic potential of anti-Siglec-F antibodies in a murine model of allergic rhinitis. METHODS Twenty-eight BALB/c mice were used. In group A (control group, n = 7), mice were sensitized and challenged with saline. In group B (ovalbumin [OVA] challenge group, n = 7), OVA was used for i.p. sensitization and intranasal challenge. Mice in group C (control IgG group, n = 7) or those in group D (anti-Siglec-F group, n = 7) had been given rabbit control IgG or anti-Siglec-F antibody injections, respectively. We assessed the number of nose-scratching events; serum total/OVA-specific IgE; the number of eosinophils, neutrophils, and lymphocytes in bronchoalveolar lavage (BAL) fluid; histopathological changes in nasal cavity tissues; and the levels of IL-4, IL-5, and IL-13 in BAL fluid. RESULTS Mice in group D had significantly less nose scratching. Serum total and OVA-specific IgE were not significantly changed. The number of eosinophils in BAL fluid and in the lamina propria of the nasal cavity mucosa was significantly decreased with anti-Siglec-F antibody treatment. The levels of Th2 cytokines such as IL-4, IL-5, and IL-13 were also significantly decreased with anti-Siglec-F antibody treatment. CONCLUSION Anti-Siglec-F antibody has beneficial effects in a mouse model of experimental allergic rhinitis.
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Affiliation(s)
- Young Hyo Kim
- Department of Otorhinolaryngology, Head and Neck Surgery, Inha University College of Medicine, Incheon, Korea
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Cho JY, Rosenthal P, Miller M, Pham A, Aceves S, Sakuda S, Broide DH. Targeting AMCase reduces esophageal eosinophilic inflammation and remodeling in a mouse model of egg induced eosinophilic esophagitis. Int Immunopharmacol 2013; 18:35-42. [PMID: 24239745 DOI: 10.1016/j.intimp.2013.10.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2013] [Revised: 10/25/2013] [Accepted: 10/28/2013] [Indexed: 01/07/2023]
Abstract
Studies of AMCase inhibition in mouse models of lung eosinophilic inflammation have produced conflicting results with some studies demonstrating inhibition of eosinophilic inflammation and others not. No studies have investigated the role of AMCase inhibition in eosinophilic esophagitis (EoE). We have used a mouse model of egg (OVA) induced EoE to determine whether pharmacologic inhibition of AMCase with allosamidin reduced eosinophilic inflammation and remodeling in the esophagus in EoE. Administration of intra-esophageal OVA for 6weeks to BALB/c mice induced increased levels of esophageal eosinophils, mast cells, and features of esophageal remodeling (fibrosis, basal zone hyperplasia, deposition of the extracellular matrix protein fibronectin). Administration of intraperitoneal (ip) allosamidin to BALB/c mice significantly inhibited AMCase enzymatic activity in the esophagus. Pharmacologic inhibition of AMCase with ip allosamidin inhibited both OVA induced increases in esophageal eosinophilic inflammation and OVA induced esophageal remodeling (fibrosis, epithelial basal zone hyperplasia, extracellular matrix deposition of fibronectin). This inhibition of eosinophilic inflammation in the esophagus by ip allosamidin was associated with reduced eotaxin-1 expression in the esophagus. Oral allosamidin inhibited eosinophilic inflammation in the epithelium but did not inhibit esophageal remodeling. These studies suggest that pharmacologic inhibition of AMCase results in inhibition of eosinophilic inflammation and remodeling in the esophagus in a mouse model of egg induced EoE partially through effects in the esophagus on reducing chemokines (i.e. eotaxin-1) implicated in the pathogenesis of EoE.
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Affiliation(s)
- Jae Youn Cho
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
| | - Peter Rosenthal
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
| | - Marina Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
| | - Alexa Pham
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
| | - Seema Aceves
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA; Department of Pediatrics, University of California San Diego, San Diego, CA, USA.
| | - Shohei Sakuda
- Faculty of Agriculture, The University of Tokyo, Tokyo, Japan.
| | - David H Broide
- Department of Medicine, University of California, San Diego, La Jolla, CA, USA.
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Patnode ML, Cheng CW, Chou CC, Singer MS, Elin MS, Uchimura K, Crocker PR, Khoo KH, Rosen SD. Galactose 6-O-sulfotransferases are not required for the generation of Siglec-F ligands in leukocytes or lung tissue. J Biol Chem 2013; 288:26533-45. [PMID: 23880769 PMCID: PMC3772201 DOI: 10.1074/jbc.m113.485409] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Revised: 07/21/2013] [Indexed: 12/17/2022] Open
Abstract
Eosinophil accumulation is a characteristic feature of the immune response to parasitic worms and allergens. The cell surface carbohydrate-binding receptor Siglec-F is highly expressed on eosinophils and negatively regulates their accumulation during inflammation. Although endogenous ligands for Siglec-F have yet to be biochemically defined, binding studies using glycan arrays have implicated galactose 6-O-sulfate (Gal6S) as a partial recognition determinant for this receptor. Only two sulfotransferases are known to generate Gal6S, namely keratan sulfate galactose 6-O-sulfotransferase (KSGal6ST) and chondroitin 6-O-sulfotransferase 1 (C6ST-1). Here we use mice deficient in both KSGal6ST and C6ST-1 to determine whether these sulfotransferases are required for the generation of endogenous Siglec-F ligands. First, we characterize ligand expression on leukocyte populations and find that ligands are predominantly expressed on cell types also expressing Siglec-F, namely eosinophils, neutrophils, and alveolar macrophages. We also detect Siglec-F ligand activity in bronchoalveolar lavage fluid fractions containing polymeric secreted mucins, including MUC5B. Consistent with these observations, ligands in the lung increase dramatically during infection with the parasitic nematode, Nippostrongylus brasiliensis, which is known to induce eosinophil accumulation and mucus production. Surprisingly, Gal6S is undetectable in sialylated glycans from eosinophils and BAL fluid analyzed by mass spectrometry. Furthermore, none of the ligands we describe are diminished in mice lacking KSGal6ST and C6ST-1, indicating that neither of the known galactose 6-O-sulfotransferases is required for ligand synthesis. These results establish that ligands for Siglec-F are present on several cell types that are relevant during allergic lung inflammation and argue against the widely held view that Gal6S is critical for glycan recognition by this receptor.
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Affiliation(s)
- Michael L. Patnode
- From the Department of Anatomy and Program in Biomedical Sciences, University of California, San Francisco, California 94143-0452
| | - Chu-Wen Cheng
- the Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Chi-Chi Chou
- the Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Mark S. Singer
- From the Department of Anatomy and Program in Biomedical Sciences, University of California, San Francisco, California 94143-0452
| | - Matilda S. Elin
- From the Department of Anatomy and Program in Biomedical Sciences, University of California, San Francisco, California 94143-0452
| | - Kenji Uchimura
- the Department of Biochemistry, Nagoya University Graduate School of Medicine, Aichi 466-8550, Japan
| | - Paul R. Crocker
- the Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, United Kingdom, and
| | - Kay-Hooi Khoo
- the Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan
| | - Steven D. Rosen
- From the Department of Anatomy and Program in Biomedical Sciences, University of California, San Francisco, California 94143-0452
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Kano G, Almanan M, Bochner BS, Zimmermann N. Mechanism of Siglec-8-mediated cell death in IL-5-activated eosinophils: role for reactive oxygen species-enhanced MEK/ERK activation. J Allergy Clin Immunol 2013; 132:437-45. [PMID: 23684072 PMCID: PMC4042061 DOI: 10.1016/j.jaci.2013.03.024] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Revised: 03/11/2013] [Accepted: 03/19/2013] [Indexed: 01/10/2023]
Abstract
BACKGROUND Sialic acid-binding immunoglobulin-like lectin (Siglec)-8 is expressed on human eosinophils, where its ligation induces cell death. Paradoxically, Siglec-8-mediated cell death is markedly enhanced by the presence of the activation and survival factor IL-5 and becomes independent of caspase activity. OBJECTIVE In this report we investigate the mechanism of Siglec-8-mediated cell death in activated eosinophils. METHODS Human peripheral blood eosinophils were treated with agonistic anti-Siglec-8 antibody and IL-5, and cell death was determined by using flow cytometry and morphology. Phosphorylation of mitogen-activated protein kinase (MAPK) was determined by using phosphoLuminex, flow cytometry, and Western blotting. Reactive oxygen species (ROS) accumulation was determined by using dihydrorhodamine fluorescence. RESULTS Costimulation with anti-Siglec-8 and IL-5 significantly increased the rate and proportion of cell death by means of necrosis accompanied by granule release compared with that seen after stimulation with anti-Siglec-8 alone, in which apoptosis predominated. Together with the caspase-independent mode of cell death in costimulated cells, these findings suggest the activation of a specific and distinct biochemical pathway of cell death during anti-Siglec-8/IL-5 costimulation. Phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 and MAPK-ERK kinase (MEK) 1 was significantly enhanced and sustained in costimulated cells compared with that seen in cells stimulated with IL-5 alone; anti-Siglec-8 alone did not cause ERK1/2 phosphorylation. MEK1 inhibitors blocked anti-Siglec-8/IL-5-induced cell death. ROS accumulation was induced by Siglec-8 ligation in a MEK-independent manner. In contrast, an ROS inhibitor prevented the anti-Siglec-8/IL-5-induced enhancement of ERK phosphorylation and cell death. Exogenous ROS mimicked stimulation by anti-Siglec-8 and was sufficient to induce enhanced cell death in IL-5-treated cells. Collectively, these data suggest that the enhancement of ERK phosphorylation is downstream of ROS generation. CONCLUSIONS In activated eosinophils ligation of Siglec-8 leads to ROS-dependent enhancement of IL-5-induced ERK phosphorylation, which results in a novel mode of biochemically regulated eosinophil cell death.
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Affiliation(s)
- Gen Kano
- Division of Allergy & Immunology, Cincinnati Children’s Hospital, and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Maha Almanan
- Division of Allergy & Immunology, Cincinnati Children’s Hospital, and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Bruce S. Bochner
- Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nives Zimmermann
- Division of Allergy & Immunology, Cincinnati Children’s Hospital, and Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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The role of lung epithelial ligands for Siglec-8 and Siglec-F in eosinophilic inflammation. Curr Opin Allergy Clin Immunol 2013; 13:106-11. [PMID: 23160308 DOI: 10.1097/aci.0b013e32835b594a] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE OF REVIEW Siglec-8 and Siglec-F are single pass transmembrane inhibitory receptors found on the surface of human and mouse eosinophils, respectively, but very little is known about their physiologic glycan ligands. This article reviews the latest knowledge on this topic and outlines the strategies being used to further define the production and glycobiochemical nature of these molecules in the lung. RECENT FINDINGS Both Siglec-8 and Siglec-F recognize the same glycan structure, namely 6'-sulfated sialyl Lewis X, as determined using glycan array technologies. Studies have identified α2,3-linked sialylated glycoprotein structures localized to mouse airway epithelium in tissue sections, where their constitutive expression requires the specific sialyltransferase St3gal3. Expression of these ligands in lung is enhanced during allergic inflammation and by cytokines such as IL-13, and is maintained in primary air-liquid interface cultures of mouse lung epithelium. Further characterization suggests that they are high molecular weight sialylated proteins, putatively mucins. By combining analytic glycomics, glycoproteomic mapping, and further in-vitro eosinophil experimentation including the ability of candidate structures to enhance eosinophil apoptosis, a finely detailed appreciation of the structural requirements for productive Siglec-8 and Siglec-F engagement should soon emerge. SUMMARY An enhanced understanding of Siglec-F, Siglec-8, and their ligands should improve our understanding of endogenous lung pathways limiting the survival of eosinophils within the airway in diseases such as asthma. Knowledge of this biology may also result in novel opportunities for drug development involving glycans and glycomimetics that selectively bind to Siglec-8 and induce eosinophil death.
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Kiwamoto T, Brummet ME, Wu F, Motari MG, Smith DF, Schnaar RL, Zhu Z, Bochner BS. Mice deficient in the St3gal3 gene product α2,3 sialyltransferase (ST3Gal-III) exhibit enhanced allergic eosinophilic airway inflammation. J Allergy Clin Immunol 2013; 133:240-7.e1-3. [PMID: 23830412 DOI: 10.1016/j.jaci.2013.05.018] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Revised: 04/23/2013] [Accepted: 05/16/2013] [Indexed: 02/06/2023]
Abstract
BACKGROUND Sialic acid-binding immunoglobulin-like lectin (Siglec)-F is a proapoptotic receptor on mouse eosinophils, but little is known about its natural tissue ligand. OBJECTIVE We previously reported that the St3gal3 gene product α2,3 sialyltransferase (ST3Gal-III) is required for constitutive Siglec-F lung ligand synthesis. We therefore hypothesized that attenuation of ST3Gal-III will decrease Siglec-F ligand levels and enhance allergic eosinophilic airway inflammation. METHODS C57BL/6 wild-type mice and St3gal3 heterozygous or homozygous deficient (St3gal3(+/-) and St3gal3(-/-)) mice were used. Eosinophilic airway inflammation was induced through sensitization to ovalbumin (OVA) and repeated airway OVA challenge. Siglec-F human IgG1 fusion protein (Siglec-F-Fc) was used to detect Siglec-F ligands. Lung tissue and bronchoalveolar lavage fluid (BALF) were analyzed for inflammation, as well as various cytokines and chemokines. Serum was analyzed for allergen-specific immunoglobulin levels. RESULTS Western blotting with Siglec-F-Fc detected approximately 500-kDa and approximately 200-kDa candidate Siglec-F ligands that were less abundant in St3gal3(+/-) lung extracts and nearly absent in St3gal3(-/-) lung extracts. After OVA sensitization and challenge, Siglec-F ligands were increased in wild-type mouse lungs but less so in St3gal3 mutants, whereas peribronchial and BALF eosinophil numbers were greater in the mutants, with the following rank order: St3gal3(-/-) ≥ St3gal3(+/-) > wild-type mice. Levels of various cytokines and chemokines in BALF were not significantly different among these 3 types of mice, although OVA-specific serum IgG1 levels were increased in St3gal3(-/-) mice. CONCLUSIONS After OVA sensitization and challenge, St3gal3(+/-) and St3gal3(-/-) mice have more intense allergic eosinophilic airway inflammation and less sialylated Siglec-F ligands in their airways. One possible explanation for these findings is that levels of sialylated airway ligands for Siglec-F might be diminished in mice with attenuated levels of ST3Gal-III, resulting in a reduction in a natural proapoptotic pathway for controlling airway eosinophilia.
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Affiliation(s)
- Takumi Kiwamoto
- Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Mary E Brummet
- Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Fan Wu
- Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Mary G Motari
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Md
| | - David F Smith
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Ga
| | - Ronald L Schnaar
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Zhou Zhu
- Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md
| | - Bruce S Bochner
- Department of Medicine, Division of Allergy and Clinical Immunology, Johns Hopkins University School of Medicine, Baltimore, Md.
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Mao H, Kano G, Hudson SA, Brummet M, Zimmermann N, Zhu Z, Bochner BS. Mechanisms of Siglec-F-induced eosinophil apoptosis: a role for caspases but not for SHP-1, Src kinases, NADPH oxidase or reactive oxygen. PLoS One 2013; 8:e68143. [PMID: 23840825 PMCID: PMC3695997 DOI: 10.1371/journal.pone.0068143] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 05/26/2013] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Siglec-F and Siglec-8 are functional paralog proapoptotic cell surface receptors expressed on mouse and human eosinophils, respectively. Whereas Siglec-8 mediated death involves caspases and/or reactive oxygen species (ROS) generation and mitochondrial injury, very little is known about Siglec-F-mediated signaling and apoptosis. Therefore the objective of the current experiments was to better define apoptosis pathways mediated by Siglec-F and Siglec-8. Given that Siglec-F-induced apoptosis is much less robust than Siglec-8-induced apoptosis, we hypothesized that mechanisms involved in cell death via these receptors would differ. METHODS Consequences of engagement of Siglec-F on mouse eosinophils were studied by measuring ROS production, and by performing apoptosis assays using eosinophils from normal, hypereosinophilic, NADPH oxidase-deficient, src homology domain-containing protein tyrosine phosphatase (SHP)-1-deficient, and Lyn kinase-deficient mice. Inhibitors of caspase and Src family kinase activity were also used. RESULTS Engagement of Siglec-F induced mouse eosinophil apoptosis that was modest in magnitude and dependent on caspase activity. There was no detectable ROS generation, or any role for ROS, NADPH oxidase, SHP-1, or Src family kinases in this apoptotic process. CONCLUSIONS These data suggest that Siglec-F-mediated apoptosis is different in both magnitude and mechanisms when compared to published data on Siglec-8-mediated human eosinophil apoptosis. One likely implication of this work is that models targeting Siglec-F in vivo in mice may not provide identical mechanistic predictions for consequences of Siglec-8 targeting in vivo in humans.
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Affiliation(s)
- Hui Mao
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Gen Kano
- Division of Allergy and Immunology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Sherry A. Hudson
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Mary Brummet
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Nives Zimmermann
- Division of Allergy and Immunology, Cincinnati Children’s Hospital Medical Center and University of Cincinnati College of Medicine, Cincinnati, Ohio, United States of America
| | - Zhou Zhu
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Bruce S. Bochner
- Division of Allergy and Clinical Immunology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
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Suzukawa M, Miller M, Rosenthal P, Cho JY, Doherty TA, Varki A, Broide D. Sialyltransferase ST3Gal-III regulates Siglec-F ligand formation and eosinophilic lung inflammation in mice. THE JOURNAL OF IMMUNOLOGY 2013; 190:5939-48. [PMID: 23677475 DOI: 10.4049/jimmunol.1203455] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Sialic acid-binding, Ig-like lectin (Siglec)-F is highly expressed on mouse eosinophils and plays an important role in regulating levels of eosinophilic lung inflammation. In this study we investigated the mechanism of constitutive and inducible Siglec-F ligand expression by lung airway epithelial cells and inflammatory cells in wild-type (WT) and genetically altered mice (ST3Gal-III heterozygotes, Fuc-TIV/VII double null, STAT6 null). Flow cytometry demonstrated that Siglec-F ligands are constitutively expressed in vitro and in vivo in selected lung cell types (epithelial cells, eosinophils, macrophages, and mast cells, but not CD4, CD8, or B cells) and are induced in response to divergent stimuli, including innate stimuli (TLR ligands, Alternaria), Th2 cytokines (IL-4, IL-13), and adaptive immune stimuli (OVA allergen). Furthermore, studies of deficient mice demonstrated the greater importance of the sialyltransferase ST3Gal-III compared with fucosyltransferases Fuc-TIV/VII in the synthesis of the constitutive and inducible Siglec-F ligands by lung epithelial and nonepithelial cells. In keeping with this, ST3Gal-III heterozygote mice (deficient in expression of Siglec-F ligands) also had significantly enhanced OVA-induced eosinophilic airway inflammation associated with reduced eosinophil apoptosis. Reduced eosinophil apoptosis in the lung of ST3Gal-III-deficient mice is likely mediated by reduced epithelial expression of Siglec-F ligands as WT eosinophils (which highly express Siglec-F) cultured with ST3Gal-III-deficient epithelial cells (which do not express Siglec-F ligand) showed reduced eosinophil apoptosis compared with WT eosinophils cultured with WT epithelial cells. Overall, these studies demonstrate that ST3Gal-III plays an important role in Siglec-F ligand formation and eosinophil apoptosis with resultant effects on eosinophilic inflammation in the lung.
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Affiliation(s)
- Maho Suzukawa
- Department of Medicine, University of California San Diego, San Diego, CA 92093, USA
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Fulkerson PC, Rothenberg ME. Targeting eosinophils in allergy, inflammation and beyond. Nat Rev Drug Discov 2013; 12:117-29. [PMID: 23334207 DOI: 10.1038/nrd3838] [Citation(s) in RCA: 335] [Impact Index Per Article: 30.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Eosinophils can regulate local immune and inflammatory responses, and their accumulation in the blood and tissue is associated with several inflammatory and infectious diseases. Thus, therapies that target eosinophils may help control diverse diseases, including atopic disorders such as asthma and allergy, as well as diseases that are not primarily associated with eosinophils, such as autoimmunity and malignancy. Eosinophil-targeted therapeutic agents that are aimed at blocking specific steps involved in eosinophil development, migration and activation have recently entered clinical testing and have produced encouraging results and insights into the role of eosinophils. In this Review, we describe recent advances in the development of first-generation eosinophil-targeted therapies and highlight strategies for using personalized medicine to treat eosinophilic disorders.
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Affiliation(s)
- Patricia C Fulkerson
- Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, Ohio 45229, USA.
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Wan D, Liu X, Li G. The effects of montelukast on eosinophilic gastroenteritis in a mouse model. Immunopharmacol Immunotoxicol 2012; 35:292-5. [PMID: 23240855 DOI: 10.3109/08923973.2012.745871] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Gastrointestinal eosinophilic (EG) is a rare and heterogeneous condition characterized by patchy or diffuse eosinophilic infiltration of gastrointestinal tissue. Pharmacological study so far has demonstrated that montelukast, an oral leukotriene receptor antagonist, might be considered in patients with this disease. The aim of this study was to evaluate the effect of montelukast on oral ovalbumin (OVA) allergen induced EG inflammation in mice and to suggest some mechanisms underlying this effect. Twenty-four mice were divided into three experimental groups: PBS control, OVA group, and montelukast treated group. The mice were sensitized intraperitoneally and challenged intragastrically with OVA, and were treated with montelukast. Gastrointestinal symptoms were observed after challenged intragastrically with OVA. Eosinophils count in blood, serum OVA specific IgE and gastrointestinal histology were evaluated. Montelukast could significantly reduce the severity of oral allergen-induced eosinophilic inflammation, villous atrophy, and associated symptoms of weight loss associated with diarrhea. Montelukast also could ameliorate OVA-induced gastrointestinal pathological lesions, which was associated with the decrease of IgE and LTD4 levels, and this might be one of the important mechanisms of montelukast that protected gastrointestinal injury from EG. These findings indicated that montelukast therapy may be a novel therapeutic approach for EG and other eosinophil-mediated diseases.
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Affiliation(s)
- Daihong Wan
- Provincial Hospital Affiliated to Shandong University, Jinan, 250014, PR China
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Effect of anti-siglec-f antibody and reactive oxygen species blocking on histamine release in urinary bladder of ovalbumin-treated mice. Int Neurourol J 2012; 16:122-5. [PMID: 23094217 PMCID: PMC3469830 DOI: 10.5213/inj.2012.16.3.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Accepted: 09/28/2012] [Indexed: 11/11/2022] Open
Abstract
Purpose Sialic acid-binding Ig-like lectin (Siglec) is an immune inhibitory receptor that plays a role in the negative regulation of the activation of immune cells. This study aimed to evaluate the effects of anti-Siglec-F on plasma and urinary histamine levels in ovalbumin (OVA)-challenged urinary bladder in mice. Methods Thirty BALB/c mice were used. In group I (control group, n=5), mice were sensitized with OVA and challenged with saline. In group II (OVA challenge group, n=5), OVA was used for intraperitoneal sensitization and intravesical challenge. The challenged mice in group III (control immunoglobulin G [IgG] group, n=5) and those in group IV (anti-Siglec-F group, n=5) were intraperitoneally pretreated with rabbit control IgG or anti-Siglec-F antibody, respectively. In groups V (N-acetylcysteine [NAC] in OVA challenge group, n=5) and VI (control NAC only, n=5), mice were pretreated with NAC. Results Urinary histamine concentrations were significantly higher 7 days after intravesical OVA challenge (P<0.01), whereas plasma histamine levels were not. Pretreatment with anti-Siglec-F antibody significantly prevented the increase in urinary histamine release (P<0.05), whereas pretreatment with the IgG antibody control did not. Also, pretreatment of the OVA challenge group with NAC did not affect the histamine concentration in either urine or plasma. Conclusions Systemic anti-Siglec-F treatment showed anti-allergic effects at least on local histamine release, particularly in the lower urinary bladder.
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Kiwamoto T, Kawasaki N, Paulson JC, Bochner BS. Siglec-8 as a drugable target to treat eosinophil and mast cell-associated conditions. Pharmacol Ther 2012; 135:327-36. [PMID: 22749793 PMCID: PMC3587973 DOI: 10.1016/j.pharmthera.2012.06.005] [Citation(s) in RCA: 116] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 06/07/2012] [Indexed: 12/19/2022]
Abstract
Siglecs (sialic acid immunoglobulin-like lectins) are members of the immunoglobulin gene family that contain sialoside binding N-terminal domains. They are cell surface proteins found predominantly on cells of the immune system. Among them, Siglec-8 is uniquely expressed by human eosinophils and mast cells, as well as basophils. Engaging this structure with antibodies or glycan ligands results in apoptosis in human eosinophils and inhibition of release of preformed and newly generated mediators from human mast cells without affecting their survival. Pro-apoptotic effects are also seen when its closest functional paralog, Siglec-F, on mouse eosinophils is similarly engaged in vitro, and beneficial effects are observed after administration of Siglec-F antibody using models of eosinophilic pulmonary and gastrointestinal inflammation in vivo. Siglec-8 targeting may thus provide a means to specifically inhibit or deplete these cell types. Cell-directed therapies are increasingly sought after by the pharmaceutical industry for their potential to reduce side effects and increase safety. The challenge is to identify suitable targets on the cell type of interest, and selectively deliver a therapeutic agent. By targeting Siglec-8, monoclonal antibodies and glycan ligand-conjugated nanoparticles may be ideally suited for treatment of eosinophil and mast cell-related diseases, such as asthma, chronic rhinosinusitis, chronic urticaria, hypereosinophilic syndromes, mast cell and eosinophil malignancies and eosinophilic gastrointestinal disorders.
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Affiliation(s)
- Takumi Kiwamoto
- Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
| | - Norihito Kawasaki
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - James C. Paulson
- Department of Chemical Physiology, The Scripps Research Institute, La Jolla, CA 92037 USA
| | - Bruce S. Bochner
- Department of Medicine, Division of Allergy and Clinical Immunology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21224, USA
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Crocker PR, McMillan SJ, Richards HE. CD33-related siglecs as potential modulators of inflammatory responses. Ann N Y Acad Sci 2012; 1253:102-11. [DOI: 10.1111/j.1749-6632.2011.06449.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Farid SS, Mirshafiey A, Razavi A. Siglec-8 and Siglec-F, the new therapeutic targets in asthma. Immunopharmacol Immunotoxicol 2012; 34:721-6. [PMID: 22324980 DOI: 10.3109/08923973.2011.589453] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The recruitment of eosinophils from the circulation into the airway is a prominent feature of allergic asthma. Persistent inflammatory responses may arise from inefficient mechanisms for resolution of inflammation, including delayed apoptosis. Several studies suggest that eosinophil apoptosis is delayed in asthma. Sialic acid-binding immunoglobulin-like lectins are characterized by their sequence similarities and abilities to bind sialic acids in glycoproteins and glycolipids. Siglec-8 is uniquely expressed on eosinophils, mast cells, and basophils. Engagement of Siglec-8 on blood eosinophils results in caspase- and mitochondria-dependent apoptosis. Eosinophil apoptosis is an important therapeutic target for the development of novel anti-asthma treatments that specifically target the eosinophil.
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Affiliation(s)
- Sima Sh Farid
- Department of Immunology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran
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42
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von Gunten S, Simon HU. Granulocyte death regulation by naturally occurring autoantibodies. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 750:157-72. [PMID: 22903673 DOI: 10.1007/978-1-4614-3461-0_12] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Programmed cell death (PCD) plays a central role in the regulation of granulocytes that are key effector cells of the innate immune system. Granulocytes are produced in high amounts in the bone marrow. A safe elimination of granulocytes by cell death (apoptosis) is essential to maintain the numbers of these cells balanced. In many acute and chronic inflammatory diseases, delayed apoptosis is one mechanism that contributes to accumulation of neutrophil and eosinophil granulocytes at the site of inflammation. On the other hand, a safe elimination of granulocytes by cell death is required to avoid unwanted tissue damage for instance by secretion of toxic products from these cells. Recent evidence shows that humans produce an array of naturally occurring autoantibodies (NAbs) with the capacity to regulate granulocyte death, including agonistic and antagonistic NAbs that bind to the receptors Fas, Siglec-8, and Siglec-9. Together with other factors, these various NAbs exhibit different properties in terms of the form of cell death they induce, the molecular signaling pathways they engage, as well as the efficacy or potency by which they induce cell death. Moreover, several regulatory mechanisms seem to exist that control their biological activity. Novel insights support the concept of granulocyte death regulation by NAbs, which might have important implications for our understanding of the pathogenesis and treatment of inflammatory diseases, including many autoimmune and allergic disorders.
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Cariddi L, Escobar F, Sabini C, Torres C, Reinoso E, Cristofolini A, Comini L, Núñez Montoya S, Sabini L. Apoptosis and mutagenicity induction by a characterized aqueous extract of Baccharis articulata (Lam.) Pers. (Asteraceae) on normal cells. Food Chem Toxicol 2011; 50:155-61. [PMID: 22107990 DOI: 10.1016/j.fct.2011.11.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Revised: 10/21/2011] [Accepted: 11/03/2011] [Indexed: 10/15/2022]
Abstract
In a previous study we have demonstrated that cold aqueous extract of Baccharis articulata (Ba-CAE) induced the death of human peripheral blood mononuclear cells (PBMCs) and exerted low mutagenic effects on mice at 6h after administration. The aim of this work was to investigate whether the PBMCs death induced by Ba-CAE is due to apoptosis, and whether this extract exerts mutagenic effects on mice at 24 and 48h after administration. In addition, Ba-CAE was chemically characterized. PBMCs from healthy volunteers were exposed to extract (10, 20, 40, 80, 160, 320, 640 and 1280μg/mL) for 18-24h. Cell viability was determined by staining of trypan blue dye exclusion method. Apoptosis was determined by Hoechst 33258 staining, TUNEL, and DNA fragmentation analysis by agarose gel electrophoresis. BALB/c mice were injected with extract (1800, 900 and 450mg/kg) and sacrificed at 24 and 48h postinjection. Bone marrow samples were used to assess chromosome mutations by the micronucleus test. The extract induced PBMCs death by apoptosis and increased the frequency of micronuclei in bone marrow. The phytochemical study of Ba-CAE showed the presence of flavones as luteolin and acacetin, caffeoylquinic acids as chlorogenic acid, and tannins.
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Affiliation(s)
- Laura Cariddi
- Departamento de Microbiología e Inmunología, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
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Yamakawa Y, Ohtsuka Y, Ohtani K, Fujii T, Nagata S, Yamashiro Y, Shimizu T. Effects of leukotriene receptor antagonists on peripheral eosinophil counts and serum IgE levels in children with food allergy. Drugs R D 2011; 10:147-54. [PMID: 20945945 PMCID: PMC3586155 DOI: 10.2165/11586150-000000000-00000] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Although the efficacy of leukotriene receptor antagonists (LTRAs) for bronchial asthma is already established, their effect on food allergy remains unclear. OBJECTIVE To investigate the efficacy of LTRAs in children with food allergy. METHODS This retrospective study examined 65 children with food allergy who were aged between 3 and 36 months (mean 14 ± 9.6 months) from 2005 to 2008. Thirty-two children were treated as a dietary control group by avoiding any antigenic foods to which they had previously experienced adverse reactions. The remaining 33 children, designated the LTRA group, were treated with pranlukast (7 mg/kg bodyweight/day) in addition to maintaining dietary control. Clinical symptoms and laboratory data before and after 1 year of treatment were compared between the groups. RESULTS Allergic symptoms improved in both the dietary controlled and LTRA groups, and there was no significant difference observed in the clinical parameters examined between the groups after the 1-year trial. Peripheral eosinophil count, serum IgE, interleukin (IL)-4, IL-5, IL-6, and eosinophil cationic protein (ECP) levels in children with food allergy were above standardized values in both groups. Although both the dietary controlled and LTRA groups showed a decreased eosinophil count (-273 ± 232 vs -595 ± 295/μL; p < 0.05 and p < 0.001, respectively), only children treated with LTRA showed a significant decrease in serum IgE (-73.5 ± 115 IU/mL; p < 0.01); conversely, the control group exhibited a significant increase in serum IgE (+159 ± 138 IU/mL; p < 0.01). Furthermore, the LTRA group also showed a significant decrease in serum IL-4 (54.5 ± 31.0 to 27.3 ± 10.1 pg/mL), IL-5 (6.7 ± 5.2 to 5.0 ± 0.4 pg/mL), and ECP (45.4 ± 15.0 to 15.0 ± 9.8 μg/L) levels (p < 0.05 for each). CONCLUSION Early intervention with LTRAs may be effective in regulating eosinophil count and serum IgE, IL-4, IL-5, and ECP levels. These data support the potential effectiveness of LTRAs in young children with food allergy to prevent further allergic development.
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Affiliation(s)
- Yoko Yamakawa
- Department of Pediatrics and Adolescent Medicine, Juntendo University School of Medicine, Tokyo, Japan
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Siglec-F inhibition reduces esophageal eosinophilia and angiogenesis in a mouse model of eosinophilic esophagitis. J Pediatr Gastroenterol Nutr 2011; 53:409-16. [PMID: 21970996 PMCID: PMC3980963 DOI: 10.1097/mpg.0b013e3182182ff8] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
OBJECTIVES Eosinophilic esophagitis (EoE) is a disorder characterized histologically by tissue eosinophilia. Sialic acid-binding immunoglobulin-like lectin (Siglec-F) is a receptor highly expressed on mouse eosinophils and mediates eosinophilic apoptosis. We investigated whether administration of an anti-Siglec-F Ab would reduce esophageal eosinophilic inflammation and remodeling in a mouse model of egg ovalbumin (OVA)-induced EoE. SUBJECTS AND METHODS Three groups of mice were studied (no OVA, OVA + anti-Siglec-F Ab, and OVA + isotype control Ab). Mice were sensitized intraperitoneally and then challenged chronically with intraesophageal OVA. Levels of esophageal eosinophils and features of remodeling (angiogenesis, vascular endothelial growth factor expression, deposition of fibronectin, basal zone hyperplasia, and fibrosis) were quantitated by immunohistochemistry and image analysis. RESULTS Administration of an anti-Siglec-F Ab to OVA-challenged mice significantly reduced levels of esophageal eosinophils, down to levels noted in non-OVA-challenged mice. The anti-Siglec-F Ab also reduced features of OVA-induced remodeling, including angiogenesis, basal zone hyperplasia, and fibronectin deposition. The reduced angiogenesis in anti-Siglec-F Ab-treated mice was associated with reduced numbers of vascular endothelial growth factor-positive cells in the esophagus. The anti-Siglec-F antibody did not significantly reduce esophageal fibrosis as assessed by trichrome staining. CONCLUSIONS Administration of an anti-Siglec-F antibody significantly decreased the number of eosinophils in the esophagus in a mouse model of OVA-induced EoE. The reduction in eosinophilic inflammation was associated with a significant decrease in levels of angiogenesis, deposition of fibronectin, and basal zone hyperplasia. Studies in this pre-clinical model of EoE suggest that Siglec-F (and its human paralog Siglec-8) may be novel therapeutic targets to reduce eosinophilic inflammation in EoE.
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Developmental, malignancy-related, and cross-species analysis of eosinophil, mast cell, and basophil siglec-8 expression. J Clin Immunol 2011; 31:1045-53. [PMID: 21938510 DOI: 10.1007/s10875-011-9589-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 09/01/2011] [Indexed: 12/28/2022]
Abstract
OBJECTIVE The aim of this study is to determine when during hematopoiesis Siglec-8 gets expressed, whether it is expressed on hematologic malignancies, and if there are other non-human species that express Siglec-8. METHODS Siglec-8 mRNA and cell surface expression was monitored during in vitro maturation of human eosinophils and mast cells. Flow cytometry was performed on human blood and bone marrow samples, and on blood samples from dogs, baboons, and rhesus and cynomolgus monkeys. RESULTS Siglec-8 is a late maturation marker. It is detectable on eosinophils and basophils from subjects with chronic eosinophilic leukemia, chronic myelogenous leukemia, and on malignant and non-malignant bone marrow mast cells, as well as the HMC-1.2 cell line. None of the Siglec-8 monoclonal antibodies tested recognized leukocytes from dogs, baboons, and rhesus and cynomolgus monkeys. CONCLUSIONS Siglec-8-based therapies should not target immature human leukocytes but should recognize mature and malignant eosinophils, mast cells, and basophils. So far, there is no suitable species for preclinical testing of Siglec-8 monoclonal antibodies.
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Abstract
The rates of eosinophilic gastrointestinal disorders appear to be increasing. The most common of these is eosinophilic esophagitis (EoE) which is a clinicopathologic condition consisting of characteristic symptoms and endoscopic features accompanied by a pan-esophageal, acid resistant epithelial eosinophilia of greater than equal to 15 per high power field. Typical symptoms include dysphagia and abdominal pain. Typical endoscopic features include pallor, plaques, furrows, concentric rings. Complications include food impactions and strictures. EoE resolution with food elimination diets provides evidence that EoE is a food-antigen driven process. In vitro and microarray studies have identified specific immunologic factors underlying EoE pathogenesis. Other gastrointestinal manifestations of food intolerances/allergy include food protein induced enterocolitis syndrome.
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Affiliation(s)
- Jaime Liou Wolfe
- Division of Gastroenterology, Department of Surgery, Children's National Medical Center, Washington, DC, USA
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48
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Guo JP, Brummet ME, Myers AC, Na HJ, Rowland E, Schnaar RL, Zheng T, Zhu Z, Bochner BS. Characterization of expression of glycan ligands for Siglec-F in normal mouse lungs. Am J Respir Cell Mol Biol 2011; 44:238-43. [PMID: 20395633 PMCID: PMC3049235 DOI: 10.1165/rcmb.2010-0007oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Accepted: 03/06/2010] [Indexed: 11/24/2022] Open
Abstract
Sialic acid-binding immunoglobulin-like lectin (Siglec)-F, an inhibitory receptor on mouse eosinophils, preferentially recognizes the glycan ligand 6'-sulfated sialyl Lewis X, but little is known about the requirements for its lung expression. RT-PCR and immunohistochemistry were used to detect and localize the sulfotransferase keratin sulfate galactose 6-O sulfotransferase (KSGal6ST, also known as carbohydrate sulfotransferase 1; gene name, Chst1) that is putatively required for 6'-sulfated Sialyl Lewis X synthesis. RT-PCR detected the greatest constitutive expression of Chst1 in lung, liver, and spleen tissue. Immunohistochemistry localized the expression of KSGal6ST in lung tissue primarily to airway epithelium. Siglec-F-Ig fusion protein selectively bound in a similar pattern, and was unaffected in lung tissue treated with methanol or deficient in Type 2 α2,3 sialyltransferase (St3gal2), but was eliminated by proteinase K or sialidase, and was absent in tissue deficient in the Type 3 α2,3 sialyltransferase (St3gal3). Binding of the Siglec-F-Ig fusion protein was similar in pattern to, and completely blocked by, a plant lectin recognizing α2,3-linked sialic acid. Thus, α2,3-linked sialic acid-containing glycoprotein Siglec-F ligands and the enzymes required for their synthesis are constitutively expressed in murine lungs, especially by airway epithelium. St3gal3, but not St3gal2, is required for constitutive Siglec-F ligand synthesis. The survival of eosinophils entering the lung may be shortened by encountering these Siglec-F sialoside ligands.
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MESH Headings
- Animals
- Antibodies, Anti-Idiotypic
- Antibodies, Monoclonal/metabolism
- Antibodies, Monoclonal, Humanized
- Antigens, Differentiation, Myelomonocytic/metabolism
- Base Sequence
- DNA Primers/genetics
- Female
- Ligands
- Lung/immunology
- Lung/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Omalizumab
- Polysaccharides/immunology
- Polysaccharides/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Recombinant Fusion Proteins/metabolism
- Respiratory Mucosa/immunology
- Respiratory Mucosa/metabolism
- Sialic Acid Binding Immunoglobulin-like Lectins
- Sialyltransferases/deficiency
- Sialyltransferases/genetics
- Sialyltransferases/metabolism
- Sulfotransferases/genetics
- Sulfotransferases/metabolism
- beta-Galactoside alpha-2,3-Sialyltransferase
- Carbohydrate Sulfotransferases
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Affiliation(s)
- Jin P. Guo
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Mary E. Brummet
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Allen C. Myers
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ho Jeong Na
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Elizabeth Rowland
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Ronald L. Schnaar
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Tao Zheng
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Zhou Zhu
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Bruce S. Bochner
- Division of Allergy and Clinical Immunology, Department of Medicine, and Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
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Cho JY, Song DJ, Pham A, Rosenthal P, Miller M, Dayan S, Doherty TA, Varki A, Broide DH. Chronic OVA allergen challenged Siglec-F deficient mice have increased mucus, remodeling, and epithelial Siglec-F ligands which are up-regulated by IL-4 and IL-13. Respir Res 2010; 11:154. [PMID: 21040544 PMCID: PMC2988013 DOI: 10.1186/1465-9921-11-154] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2009] [Accepted: 11/01/2010] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND In this study we examined the role of Siglec-F, a receptor highly expressed on eosinophils, in contributing to mucus expression, airway remodeling, and Siglec-F ligand expression utilizing Siglec-F deficient mice exposed to chronic allergen challenge. METHODS Wild type (WT) and Siglec-F deficient mice were sensitized and challenged chronically with OVA for one month. Levels of airway inflammation (eosinophils), Siglec-F ligand expresion and remodeling (mucus, fibrosis, smooth muscle thickness, extracellular matrix protein deposition) were assessed in lung sections by image analysis and immunohistology. Airway hyperreactivity to methacholine was assessed in intubated and ventilated mice. RESULTS Siglec-F deficient mice challenged with OVA for one month had significantly increased numbers of BAL and peribronchial eosinophils compared to WT mice which was associated with a significant increase in mucus expression as assessed by the number of periodic acid Schiff positive airway epithelial cells. In addition, OVA challenged Siglec-F deficient mice had significantly increased levels of peribronchial fibrosis (total lung collagen, area of peribronchial trichrome staining), as well as increased numbers of peribronchial TGF-β1+ cells, and increased levels of expression of the extracellular matrix protein fibronectin compared to OVA challenged WT mice. Lung sections immunostained with a Siglec-Fc to detect Siglec-F ligand expression demonstrated higher levels of expression of the Siglec-F ligand in the peribronchial region in OVA challenged Siglec-F deficient mice compared to WT mice. WT and Siglec-F deficient mice challenged intranasally with IL-4 or IL-13 had significantly increased levels of airway epithelial Siglec-F ligand expression, whereas this was not observed in WT or Siglec-F deficient mice challenged with TNF-α. There was a significant increase in the thickness of the peribronchial smooth muscle layer in OVA challenged Siglec-F deficient mice, but this was not associated with significant increased airway hyperreactivity compared to WT mice. CONCLUSIONS Overall, this study demonstrates an important role for Siglec-F in modulating levels of chronic eosinophilic airway inflammation, peribronchial fibrosis, thickness of the smooth muscle layer, mucus expression, fibronectin, and levels of peribronchial Siglec-F ligands suggesting that Siglec-F may normally function to limit levels of chronic eosinophilic inflammation and remodeling. In addition, IL-4 and IL-13 are important regulators of Siglec-F ligand expression by airway epithelium.
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Affiliation(s)
- Jae Youn Cho
- Department of Medicine, University of California San Diego, USA
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50
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Abstract
An intricate network of activation and inhibitory signals tightly regulates immune responses. To date, multiple activation receptors have been described. These include receptors that mediate cellular functions such as adhesion, chemotaxis, cytokine signalling, mediator release, survival and phagocytosis. In contrast to these activation pathways, an opposing and suppressive receptor system has evolved. These receptors can override the signals elicited by the activation pathways and are broadly termed inhibitory receptors. Inhibitory receptors share unique intracellular signalling motifs and have key roles in various cellular and pathological conditions. Therefore, such receptors are potential targets for future therapeutics. In this review, we will discuss the structure and function of inhibitory receptors. In particular, we will focus on the expression and function of inhibitory receptors on mast cells and eosinophils and illustrate strategies for their inhibition in the settings of allergic inflammation.
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Affiliation(s)
- D Shik
- Department of Microbiology and Human Immunology, The Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, Israel
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