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Ma Y, Liu Z, Jiang L, Wang L, Li Y, Liu Y, Wang Y, Yang GY, Ding J, Zhang Z. Endothelial progenitor cell transplantation attenuates synaptic loss associated with enhancing complement receptor 3-dependent microglial/macrophage phagocytosis in ischemic mice. J Cereb Blood Flow Metab 2023; 43:379-392. [PMID: 36457150 PMCID: PMC9941864 DOI: 10.1177/0271678x221135841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 09/01/2022] [Accepted: 09/26/2022] [Indexed: 12/04/2022]
Abstract
Endothelial progenitor cell (EPC) transplantation has therapeutic effects in cerebral ischemia. However, how EPCs modulate microglial activity remains unclear. In the study, we explored whether EPCs modulated microglial/macrophage activity and facilitated injured brain repair. Adult male mice (n = 184) underwent transient middle cerebral artery occlusion, and EPCs were transplanted into the brain immediately after ischemia. Microglial/macrophage activity and complement receptor 3 (CR3) expression were evaluated in ischemic brains and cultured microglia. CR3 agonist leukadherin-1 was administrated into mice immediately after ischemia to imitate the effects of EPCs. Synaptophysin and postsynaptic density protein 95 (PSD-95) expressions were detected in EPC- and leukadherin-1 treated mice. We found that EPC transplantation increased the number of M2 microglia/macrophage-phagocytizing apoptotic cells and CR3 expression in ischemic brains at 3 days after ischemia (p < 0.05). EPC-conditional medium or cultured EPCs increased microglial migration and phagocytosis and upregulated CR3 expression in cultured microglia under oxygen-glucose deprivation condition (p < 0.05). Leukadherin-1 reduced brain atrophy volume and neurological deficits at 14 days after ischemia (p < 0.05). Both EPC transplantation and leukadherin-1 increased synaptophysin and PSD-95 expression at 14 days after ischemia (p < 0.05). EPC transplantation promoted CR3-mediated microglial/macrophage phagocytosis and subsequently attenuated synaptic loss. Our study provided a novel therapeutic mechanism for EPCs.
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Affiliation(s)
- Yuanyuan Ma
- Department of Neurology, Zhongshan Hospital, Fudan University,
Shanghai, China
- Department of Neurology, Ruijin Hospital, School of Medicine and
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai,
China
| | - Ze Liu
- Department of Neurology, Ruijin Hospital, School of Medicine and
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai,
China
| | - Lu Jiang
- Department of Neurology, Ruijin Hospital, School of Medicine and
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai,
China
| | - Liping Wang
- Department of Neurology, Renji Hospital, School of Medicine,
Shanghai Jiao Tong University, Shanghai, China
| | - Yongfang Li
- Department of Neurology, Ruijin Hospital, School of Medicine and
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai,
China
| | - Yanqun Liu
- Department of Neurology, Changhai Hospital, Second Military
Medical University, Shanghai, China
| | - Yongting Wang
- Department of Neurology, Ruijin Hospital, School of Medicine and
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai,
China
| | - Guo-Yuan Yang
- Department of Neurology, Ruijin Hospital, School of Medicine and
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai,
China
| | - Jing Ding
- Department of Neurology, Zhongshan Hospital, Fudan University,
Shanghai, China
| | - Zhijun Zhang
- Department of Neurology, Ruijin Hospital, School of Medicine and
School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai,
China
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Caseiro C, Dias JNR, de Andrade Fontes CMG, Bule P. From Cancer Therapy to Winemaking: The Molecular Structure and Applications of β-Glucans and β-1, 3-Glucanases. Int J Mol Sci 2022; 23:ijms23063156. [PMID: 35328577 PMCID: PMC8949617 DOI: 10.3390/ijms23063156] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/11/2022] [Accepted: 03/11/2022] [Indexed: 02/04/2023] Open
Abstract
β-glucans are a diverse group of polysaccharides composed of β-1,3 or β-(1,3-1,4) linked glucose monomers. They are mainly synthesized by fungi, plants, seaweed and bacteria, where they carry out structural, protective and energy storage roles. Because of their unique physicochemical properties, they have important applications in several industrial, biomedical and biotechnological processes. β-glucans are also major bioactive molecules with marked immunomodulatory and metabolic properties. As such, they have been the focus of many studies attesting to their ability to, among other roles, fight cancer, reduce the risk of cardiovascular diseases and control diabetes. The physicochemical and functional profiles of β-glucans are deeply influenced by their molecular structure. This structure governs β-glucan interaction with multiple β-glucan binding proteins, triggering myriad biological responses. It is then imperative to understand the structural properties of β-glucans to fully reveal their biological roles and potential applications. The deconstruction of β-glucans is a result of β-glucanase activity. In addition to being invaluable tools for the study of β-glucans, these enzymes have applications in numerous biotechnological and industrial processes, both alone and in conjunction with their natural substrates. Here, we review potential applications for β-glucans and β-glucanases, and explore how their functionalities are dictated by their structure.
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Affiliation(s)
- Catarina Caseiro
- CIISA—Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal; (C.C.); (J.N.R.D.)
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisbon, Portugal
| | - Joana Nunes Ribeiro Dias
- CIISA—Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal; (C.C.); (J.N.R.D.)
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisbon, Portugal
| | | | - Pedro Bule
- CIISA—Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, 1300-477 Lisbon, Portugal; (C.C.); (J.N.R.D.)
- Associate Laboratory for Animal and Veterinary Sciences (AL4AnimalS), 1300-477 Lisbon, Portugal
- Correspondence:
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Han X, Su X, Li Z, Liu Y, Wang S, Zhu M, Zhang C, Yang F, Zhao J, Li X, Chen F, Han L. Complement receptor 3 mediates Aspergillus fumigatus internalization into alveolar epithelial cells with the increase of intracellular phosphatidic acid by activating FAK. Virulence 2021; 12:1980-1996. [PMID: 34338598 PMCID: PMC8331038 DOI: 10.1080/21505594.2021.1958042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Complement receptor 3 (CD11b/CD18) is an important receptor that mediates adhesion, phagocytosis and chemotaxis in various immunocytes. The conidia of the medically-important pathogenic fungus, Aspergillus fumigatus can be internalized into alveolar epithelial cells to disseminate its infection in immunocompromised host; however, the role of CR3 in this process is poorly understood. In the present study, we investigated the potential role of CR3 on A. fumigatus internalization into type II alveolar epithelial cells and its effect on host intracellular PA content induced by A. fumigatus. We found that CR3 is expressed in alveolar epithelial cells and that human serum and bronchoalveolar lavage fluid (BALF) could improve A. fumigatus conidial internalization into A549 type II alveolar epithelial cell line and mouse primary alveolar epithelial cells, which were significantly inhibited by the complement C3 quencher and CD11b-blocking antibody. Serum-opsonization of swollen conidia, but not resting conidia led to the increase of cellular phosphatidic acid (PA) in A549 cells during infection. Moreover, both conidial internalization and induced PA production were interfered by CD11b-blocking antibody and dependent on FAK activity, but not Syk in alveolar epithelial cells. Overall, our results revealed that CR3 is a critical modulator of Aspergillus fumigatus internalization into alveolar epithelial cells.
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Affiliation(s)
- Xuelin Han
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Xueting Su
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Zhiqian Li
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China.,Department of Laboratory Medicine & Blood Transfusion, the 907th Hospital, Fujian, Nanping, China
| | - Yanxi Liu
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Shuo Wang
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China.,Northwest Institute of Plateau Biology, Chinese Academy of Science, Qinghai, Xining, China
| | - Miao Zhu
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Changjian Zhang
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China.,Central Laboratory of the sixth medical center of PLA general hospital, Beijing, China
| | - Fan Yang
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Jingya Zhao
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Xianping Li
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China
| | - Fangyan Chen
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
| | - Li Han
- Department for Disinfection and Infection Control, Chinese PLA Center for Disease Control and Prevention, Beijing, China
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Dickinson CM, LeBlanc BW, Edhi MM, Heffernan DS, Faridi MH, Gupta V, Cioffi WG, O'Brien X, Reichner JS. Leukadherin-1 ameliorates endothelial barrier damage mediated by neutrophils from critically ill patients. J Intensive Care 2018; 6:19. [PMID: 29568527 PMCID: PMC5855997 DOI: 10.1186/s40560-018-0289-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Accepted: 03/06/2018] [Indexed: 12/21/2022] Open
Abstract
Background Multi-organ failure occurs during critical illness and is mediated in part by destructive neutrophil-to-endothelial interactions. The β2 integrin receptor, CR3 (complement receptor 3; Mac-1; CD11b/CD18), which binds endothelial intercellular adhesion molecule-1 (ICAM-1), plays a key role in promoting the adhesion of activated neutrophils to inflamed endothelia which, when prolonged and excessive, can cause vascular damage. Leukadherin-1 (LA-1) is a small molecule allosteric activator of CR3 and has been shown to promote adhesion of blood neutrophils to inflamed endothelium and restrict tissue infiltration. Therefore, LA-1 offers a novel mechanism of anti-inflammatory action by activation, rather than inhibition, of the neutrophil CR3 integrin. However, whether promotion of neutrophil-to-endothelial interaction by this novel therapeutic is of benefit or detriment to endothelial barrier function is not known. Methods Critically ill septic and trauma patients were prospectively enrolled from the surgical and the trauma ICU. Blood was collected from these patients and healthy volunteers. Neutrophils were isolated by dextran sedimentation and adhered to TNF-α (tumor necrosis factor-α)-activated human umbilical vein endothelial (HUVEC) monolayers in the presence or absence of fMLP (formylmethionine-leucine-phenylalanine) and/or LA-1. Electric cell-substrate impedance sensing (ECIS) and exposure of underlying collagen were used to quantify endothelial barrier function and permeability. Results Neutrophils from critically ill trauma and septic patients caused similar degrees of endothelial barrier disruption which exceeded that caused by cells obtained from healthy controls both kinetically and quantitatively. LA-1 protected barrier function in the absence and presence of fMLP which served as a secondary stimulant to cause maximal loss of barrier function. LA-1 protection was also observed by quantifying collagen exposure underlying endothelial cells challenged with fMLP-stimulated neutrophils. LA-1 treatment resulted in decreased migration dynamics of neutrophils crawling on an endothelial monolayer with reduced speed (μm/s = 0.25 ± 0.01 vs. 0.06 ± 0.01, p < 0.05), path length (μm = 199.5 ± 14.3 vs. 42.1 ± 13.0, p < 0.05), and displacement (μm = 65.2 ± 4.7 vs. 10.4 ± 1.3; p < 0.05). Conclusion Neutrophils from patients with trauma or sepsis cause endothelial barrier disruption to a similar extent relative to each other. The CR3 agonist LA-1 protects endothelial barrier function from damage caused by neutrophils obtained from both populations of critically ill patients even when exposed to secondary stimulation.
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Affiliation(s)
- Catherine M Dickinson
- 1Rhode Island Hospital Division of Surgical Research, Department of Surgery, Alpert Medical School of Brown University, Providence, RI USA
| | - Brian W LeBlanc
- 1Rhode Island Hospital Division of Surgical Research, Department of Surgery, Alpert Medical School of Brown University, Providence, RI USA
| | - Muhammad M Edhi
- 1Rhode Island Hospital Division of Surgical Research, Department of Surgery, Alpert Medical School of Brown University, Providence, RI USA
| | - Daithi S Heffernan
- 1Rhode Island Hospital Division of Surgical Research, Department of Surgery, Alpert Medical School of Brown University, Providence, RI USA
| | - Mohd Hafeez Faridi
- 2College of Pharmacy, Chicago State University, Chicago, IL USA.,3Rush University Medical Center, Chicago, IL USA
| | - Vineet Gupta
- 3Rush University Medical Center, Chicago, IL USA
| | - William G Cioffi
- 1Rhode Island Hospital Division of Surgical Research, Department of Surgery, Alpert Medical School of Brown University, Providence, RI USA
| | - Xian O'Brien
- 1Rhode Island Hospital Division of Surgical Research, Department of Surgery, Alpert Medical School of Brown University, Providence, RI USA
| | - Jonathan S Reichner
- 1Rhode Island Hospital Division of Surgical Research, Department of Surgery, Alpert Medical School of Brown University, Providence, RI USA
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5
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O'Brien XM, Reichner JS. Neutrophil Integrins and Matrix Ligands and NET Release. Front Immunol 2016; 7:363. [PMID: 27698655 PMCID: PMC5027203 DOI: 10.3389/fimmu.2016.00363] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 09/02/2016] [Indexed: 12/23/2022] Open
Abstract
Neutrophils are motile and responsive to tissue injury and infection. As neutrophils emigrate from the bloodstream and migrate toward a site of affliction, they encounter the tissue extracellular matrix (ECM) and thereby engage integrins. Our laboratory studies the neutrophilic response to the fungal pathogen Candida albicans either in the filamentous state of the microbe or to the purified pathogen-associated molecular pattern, β-glucan. We have gained an appreciation for the role of integrins in regulating the neutrophil anti-Candida response and how the presence or absence of ECM can drive experimental outcome. The β2 integrin CR3 (complement receptor 3; αMβ2; Mac-1; CD11b/CD18) plays an important role in fungal recognition by its ability to bind β-glucan at a unique lectin-like domain. The presence of ECM differentially regulates essential neutrophil anti-fungal functions, including chemotaxis, respiratory burst, homotypic aggregation, and the release of neutrophil extracellular traps (NETs). We have shown that NET release to C. albicans hyphae or immobilized β-glucan occurs rapidly and without the requirement for respiratory burst on ECM. This is in contrast to the more frequently reported mechanisms of NETosis to other pathogens without the context of ECM, which occur after a prolonged lag period and require respiratory burst. As expected for an ECM-dependent phenotype, NETosis and other neutrophil functions are dependent on specific integrins. The focus of this review is the role of ECM ligation by neutrophil integrins as it pertains to host defense functions with an emphasis on lessons we have learned studying the anti-Candida response of human neutrophils.
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Affiliation(s)
- Xian M O'Brien
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, USA; Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Jonathan S Reichner
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital, Providence, RI, USA; Warren Alpert Medical School, Brown University, Providence, RI, USA
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6
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Legentil L, Paris F, Ballet C, Trouvelot S, Daire X, Vetvicka V, Ferrières V. Molecular Interactions of β-(1→3)-Glucans with Their Receptors. Molecules 2015; 20:9745-66. [PMID: 26023937 PMCID: PMC6272582 DOI: 10.3390/molecules20069745] [Citation(s) in RCA: 103] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Accepted: 05/20/2015] [Indexed: 12/01/2022] Open
Abstract
β-(1→3)-Glucans can be found as structural polysaccharides in cereals, in algae or as exo-polysaccharides secreted on the surfaces of mushrooms or fungi. Research has now established that β-(1→3)-glucans can trigger different immune responses and act as efficient immunostimulating agents. They constitute prevalent sources of carbons for microorganisms after subsequent recognition by digesting enzymes. Nevertheless, mechanisms associated with both roles are not yet clearly understood. This review focuses on the variety of elucidated molecular interactions that involve these natural or synthetic polysaccharides and their receptors, i.e., Dectin-1, CR3, glycolipids, langerin and carbohydrate-binding modules.
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MESH Headings
- Adjuvants, Immunologic/genetics
- Adjuvants, Immunologic/metabolism
- Agaricales/genetics
- Agaricales/metabolism
- Antigens, CD/genetics
- Antigens, CD/immunology
- Edible Grain/genetics
- Edible Grain/metabolism
- Gene Expression Regulation
- Glucan 1,3-beta-Glucosidase/genetics
- Glucan 1,3-beta-Glucosidase/immunology
- Glycolipids/immunology
- Glycolipids/metabolism
- Humans
- Lectins, C-Type/genetics
- Lectins, C-Type/immunology
- Macrophage-1 Antigen/genetics
- Macrophage-1 Antigen/immunology
- Mannose-Binding Lectins/genetics
- Mannose-Binding Lectins/immunology
- Receptors, Scavenger/genetics
- Receptors, Scavenger/immunology
- Signal Transduction
- Stramenopiles/genetics
- Stramenopiles/metabolism
- beta-Glucans/metabolism
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Affiliation(s)
- Laurent Legentil
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France.
- Université européenne de Bretagne, F-35000 Rennes, France.
| | - Franck Paris
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France.
- Université européenne de Bretagne, F-35000 Rennes, France.
| | - Caroline Ballet
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France.
- Université européenne de Bretagne, F-35000 Rennes, France.
| | - Sophie Trouvelot
- INRA, UMR AgroSup/INRA/uB 1347 Agroécologie, Pôle Interactions Plantes-Microorganismes-ERL CNRS 6300, 21065 Dijon Cedex, France.
| | - Xavier Daire
- INRA, UMR AgroSup/INRA/uB 1347 Agroécologie, Pôle Interactions Plantes-Microorganismes-ERL CNRS 6300, 21065 Dijon Cedex, France.
| | - Vaclav Vetvicka
- Department of Pathology, University of Louisville, Louisville, KY 40202, USA.
| | - Vincent Ferrières
- Ecole Nationale Supérieure de Chimie de Rennes, CNRS, UMR 6226, 11 Allée de Beaulieu, CS 50837, 35708 Rennes Cedex 7, France.
- Université européenne de Bretagne, F-35000 Rennes, France.
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Serhan CN, Dalli J, Colas RA, Winkler JW, Chiang N. Protectins and maresins: New pro-resolving families of mediators in acute inflammation and resolution bioactive metabolome. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1851:397-413. [PMID: 25139562 PMCID: PMC4324013 DOI: 10.1016/j.bbalip.2014.08.006] [Citation(s) in RCA: 324] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/06/2014] [Accepted: 08/09/2014] [Indexed: 02/06/2023]
Abstract
Acute inflammatory responses are protective, yet without timely resolution can lead to chronic inflammation and organ fibrosis. A systems approach to investigate self-limited (self-resolving) inflammatory exudates in mice and structural elucidation uncovered novel resolution phase mediators in vivo that stimulate endogenous resolution mechanisms in inflammation. Resolving inflammatory exudates and human leukocytes utilize DHA and other n-3 EFA to produce three structurally distinct families of potent di- and trihydroxy-containing products, with several stereospecific potent mediators in each family. Given their potent and stereoselective picogram actions, specific members of these new families of mediators from the DHA metabolome were named D-series resolvins (Resolvin D1 to Resolvin D6), protectins (including protectin D1-neuroprotectin D1), and maresins (MaR1 and MaR2). In this review, we focus on a) biosynthesis of protectins and maresins as anti-inflammatory-pro-resolving mediators; b) their complete stereochemical assignments and actions in vivo in disease models. Each pathway involves the biosynthesis of epoxide-containing intermediates produced from hydroperoxy-containing precursors from human leukocytes and within exudates. Also, aspirin triggers an endogenous DHA metabolome that biosynthesizes potent products in inflammatory exudates and human leukocytes, namely aspirin-triggered Neuroprotectin D1/Protectin D1 [AT-(NPD1/PD1)]. Identification and structural elucidation of these new families of bioactive mediators in resolution has opened the possibility of diverse patho-physiologic actions in several processes including infection, inflammatory pain, tissue regeneration, neuroprotection-neurodegenerative disorders, wound healing, and others. This article is part of a Special Issue entitled "Oxygenated metabolism of PUFA: analysis and biological relevance".
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Affiliation(s)
- Charles N Serhan
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
| | - Jesmond Dalli
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Romain A Colas
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Jeremy W Winkler
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Nan Chiang
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA
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8
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Fox ED, Heffernan DS, Cioffi WG, Reichner JS. Neutrophils from critically ill septic patients mediate profound loss of endothelial barrier integrity. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2013; 17:R226. [PMID: 24099563 PMCID: PMC4057230 DOI: 10.1186/cc13049] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 09/06/2013] [Indexed: 12/30/2022]
Abstract
Introduction Sepsis is characterized by systemic immune activation and neutrophil-mediated endothelial barrier integrity compromise, contributing to end-organ dysfunction. Studies evaluating endothelial barrier dysfunction induced by neutrophils from septic patients are lacking, despite its clinical significance. We hypothesized that septic neutrophils would cause characteristic patterns of endothelial barrier dysfunction, distinct from experimental stimulation of normal neutrophils, and that treatment with the immunomodulatory drug β-glucan would attenuate this effect. Methods Blood was obtained from critically ill septic patients. Patients were either general surgery patients (Primary Sepsis (PS)) or those with sepsis following trauma (Secondary Sepsis (SS)). Those with acute respiratory distress syndrome (ARDS) were identified. Healthy volunteers served as controls. Neutrophils were purified and aliquots were untreated, or treated with fMLP or β-glucan. Endothelial cells were grown to confluence and activated with tissue necrosis factor (TNF)-α . Electric Cell-substrate Impedance Sensing (ECIS) was used to determine monolayer resistance after neutrophils were added. Groups were analyzed by two-way analysis of variance (ANOVA). Results Neutrophils from all septic patients, as well as fMLP-normal neutrophils, reduced endothelial barrier integrity to a greater extent than untreated normal neutrophils (normalized resistance of cells from septic patients at 30 mins = 0.90 ± 0.04; at 60 mins = 0.73 ± 0.6 and at 180 mins = 0.56 ± 0.05; p < 0.05 vs normal). Compared to untreated PS neutrophils, fMLP-treated PS neutrophils caused further loss of barrier function at all time points; no additive effect was noted in stimulation of SS neutrophils beyond 30 min. Neutrophils from ARDS patients caused greater loss of barrier integrity than those from non-ARDS patients, despite similarities in age, sex, septic source, and neutrophil count. Neutrophils obtained after resolution of sepsis caused less barrier dysfunction at all time points. β-glucan treatment of septic patients’ neutrophils attenuated barrier compromise, rendering the effect similar to that induced by neutrophils obtained once sepsis had resolved. Conclusions Neutrophils from septic patients exert dramatic compromise of endothelial barrier integrity. This pattern is mimicked by experimental activation of healthy neutrophils. The effect of septic neutrophils on the endothelium depends upon the initial inflammatory event, correlates with organ dysfunction and resolution of sepsis, and is ameliorated by β-glucan.
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9
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Pillay J, Kamp VM, Pennings M, Oudijk EJ, Leenen LP, Ulfman LH, Koenderman L. Acute-phase concentrations of soluble fibrinogen inhibit neutrophil adhesion under flow conditions in vitro through interactions with ICAM-1 and MAC-1 (CD11b/CD18). J Thromb Haemost 2013; 11:1172-82. [PMID: 23581432 DOI: 10.1111/jth.12250] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2012] [Indexed: 12/30/2022]
Abstract
BACKGROUND Immobilized fibrinogen and fibrin facilitate leukocyte adhesion, as they are potent ligands for leukocyte MAC-1 (CD11b/CD18). However, fibrinogen in its soluble form also binds to MAC-1, albeit with low affinity. The level of soluble fibrinogen is increased during chronic and acute inflammation, but the function of this increase is unknown. OBJECTIVES To study the effect of soluble fibrinogen in concentrations found in severe acute inflammation on leukocyte adhesion. METHODS Isolated leukocytes and soluble fibrinogen were studied in various in vitro settings under static and under flow conditions. RESULTS Soluble fibrinogen functioned as a natural antagonist of neutrophil functions that are dependent on MAC-1, such as the respiratory burst induced by unopsonized zymosan and adhesion to ICAM-1 and heparin. In addition, soluble fibrinogen inhibited lymphocyte function-associated antigen 1-dependent lymphocyte binding to ICAM-1 through a direct interaction with ICAM-1. Soluble fibrinogen reduced MAC-1-dependent binding of interleukin-8-activated neutrophils to ICAM-1-expressing cells under flow conditions. Importantly soluble fibrinogen in acute-phase concentrations (4-10 mg mL(-1) ) dose-dependently reduced neutrophil firm adhesion to tumor necrosis factor-α-activated endothelium to 40% under flow conditions. CONCLUSIONS We propose a model in which the increased circulating concentrations of soluble fibrinogen found during the acute-phase response can act as a natural antagonist of leukocyte recruitment, and therefore might contribute to the resolution of inflammation.
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Affiliation(s)
- J Pillay
- Department of Respiratory Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
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10
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Baker's yeast β-glucan supplementation increases monocytes and cytokines post-exercise: implications for infection risk? Br J Nutr 2012; 109:478-86. [DOI: 10.1017/s0007114512001407] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Strenuous aerobic exercise is known to weaken the immune system, and while many nutritional supplements have been proposed to boost post-exercise immunity, few are known to be effective. The purpose of the present study was to evaluate whether 10 d of supplementation with a defined source of baker's yeast β-glucan (BG, Wellmune WGP®) could minimise post-exercise immunosuppression. Recreationally active men and women (n 60) completed two 10 d trial conditions using a cross-over design with a 7 d washout period: placebo (rice flour) and baker's yeast BG (250 mg/d of β-1,3/1,6-glucans derived from Saccharomyces cerevisiae) before a bout of cycling (49 ± 6 min) in a hot (38 ± 2°C), humid (45 ± 2 % relative humidity) environment. Blood was collected at baseline (before supplement), pre- (PRE), post- (POST) and 2 h (2H) post-exercise. Total and subset monocyte concentration was measured by four-colour flow cytometry. Plasma cytokine levels and lipopolysaccharide (LPS)-stimulated cytokine production were measured using separate multiplex assays. Total (CD14+) and pro-inflammatory monocyte concentrations (CD14+/CD16+) were significantly greater at POST and 2H (P< 0·05) with BG supplementation. BG supplementation boosted LPS-stimulated production of IL-2, IL-4, IL-5 and interferon-γ (IFN-γ) at PRE and POST (P< 0·05). Plasma IL-4, IL-5 and IFN-γ concentrations were greater at 2H following BG supplementation. It appears that 10 d of supplementation with BG increased the potential of blood leucocytes for the production of IL-2, IL-4, IL-5 and IFN-γ. The key findings of the present study demonstrate that BG may have potential to alter immunity following a strenuous exercise session.
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Shinohara M, Mirakaj V, Serhan CN. Functional Metabolomics Reveals Novel Active Products in the DHA Metabolome. Front Immunol 2012; 3:81. [PMID: 22566962 PMCID: PMC3342038 DOI: 10.3389/fimmu.2012.00081] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 03/29/2012] [Indexed: 01/01/2023] Open
Abstract
Endogenous mechanisms for successful resolution of an acute inflammatory response and the local return to homeostasis are of interest because excessive inflammation underlies many human diseases. In this review, we provide an update and overview of functional metabolomics that identified a new bioactive metabolome of docosahexaenoic acid (DHA). Systematic studies revealed that DHA was converted to DHEA-derived novel bioactive products as well as aspirin-triggered forms of protectins (AT-PD1). The new oxygenated DHEA-derived products blocked PMN chemotaxis, reduced P-selectin expression and platelet-leukocyte adhesion, and showed organ protection in ischemia/reperfusion injury. These products activated cannabinoid receptor (CB2 receptor) and not CB1 receptors. The AT-PD1 reduced neutrophil (PMN) recruitment in murine peritonitis. With human cells, AT-PD1 decreased transendothelial PMN migration as well as enhanced efferocytosis of apoptotic human PMN by macrophages. The recent findings reviewed here indicate that DHEA oxidative metabolism and aspirin-triggered conversion of DHA produce potent novel molecules with anti-inflammatory and organ-protective properties, opening the DHA metabolome functional roles.
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Affiliation(s)
- Masakazu Shinohara
- Center for Experimental Therapeutics and Reperfusion Injury, Department of Anesthesiology, Perioperative and Pain Medicine, Brigham and Women's Hospital, Harvard Medical School Boston, MA, USA
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Serhan CN, Fredman G, Yang R, Karamnov S, Belayev LS, Bazan NG, Zhu M, Winkler JW, Petasis NA. Novel proresolving aspirin-triggered DHA pathway. ACTA ACUST UNITED AC 2011; 18:976-87. [PMID: 21867913 DOI: 10.1016/j.chembiol.2011.06.008] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/07/2011] [Accepted: 06/20/2011] [Indexed: 01/07/2023]
Abstract
Endogenous mechanisms in the resolution of acute inflammation are of interest because excessive inflammation underlies many pathologic abnormalities. We report an aspirin-triggered DHA metabolome that biosynthesizes a potent product in inflammatory exudates and human leukocytes, namely aspirin-triggered Neuroprotectin D1/Protectin D1 [AT-(NPD1/PD1)]. The complete stereochemistry of AT-(NPD1/PD1) proved to be 10R,17R-dihydroxydocosa-4Z,7Z,11E,13E,15Z,19Z-hexaenoic acid. The chirality of hydroxyl groups and geometry of the conjugated triene system essential for bioactivity were established by matching biological materials with stereochemically pure isomers prepared by organic synthesis. AT-(NPD1/PD1) reduced neutrophil (PMN) recruitment in murine peritonitis in a dose-dependent fashion whereby neither a Δ(15)-trans-isomer nor DHA was effective. With human cells, AT-(NPD1/PD1) decreased transendothelial PMN migration as well as enhanced efferocytosis of apoptotic human PMN by macrophages. These results indicate that AT-(NPD1/PD1) is a potent anti-inflammatory proresolving molecule.
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Affiliation(s)
- Charles N Serhan
- Center for Experimental Therapeutics and Reperfusion Injury, Harvard Institutes of Medicine, Department of Anesthesiology, Perioperative, and Pain Medicine, Brigham and Women's Hospital, and Harvard Medical School, Boston, MA 02115, USA.
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Effect of yeast-derived beta-glucan in conjunction with bevacizumab for the treatment of human lung adenocarcinoma in subcutaneous and orthotopic xenograft models. J Immunother 2009; 32:703-12. [PMID: 19561538 DOI: 10.1097/cji.0b013e3181ad3fcf] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Human lung cancer is the leading cause of cancer death worldwide. Bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), in combination with chemotherapy showed significant therapeutic efficacy in human lung cancer patients. However, increased adverse effects limit its clinical utilization. Previous studies demonstrated that polysaccharide beta-glucan significantly augments antitumor monoclonal antibody-mediated efficacy via stimulation of the innate effector neutrophil complement receptor 3. Here, we explored combined beta-glucan with bevacizumab therapy for human lung cancer using murine xenograft models. To that end, human lung adenocarcinomas were screened for membrane-bound VEGF expression. Both subcutaneous and orthotopic lung cancer xenograft models were used to evaluate the combination therapy. We found that PC14PE6 adenocarcinoma cells express membrane-bound VEGF both in vitro and in vivo. Bevacizumab bound to surface VEGF on PC14PE6 cells and activated complement. In the subcutaneous PC14PE6 tumor model, beta-glucan plus bevacizumab showed augmented efficacy in terms of tumor progression and long-term survival compared with bevacizumab-treated alone. These effects were accompanied with massive complement deposition and neutrophil infiltration within tumors. However, this effect was not observed in surface-bound VEGF-negative human lung tumors. Therapeutic efficacy of beta-glucan with bevacizumab was further demonstrated in an orthotopic lung cancer model. Thus, our data suggest that beta-glucan enhances bevacizumab-mediated efficacy and may provide therapeutic benefits for lung cancers with membrane-bound VEGF expression.
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Kumar S, Ghosh D, Tuhin Kanti Biswas, Dutta U, Das P, Kundu S. Spermatheca Gland Extract of Snail (Telescopium telescopium) Has Wound Healing Potential: An Experimental Study in Rabbits. INT J LOW EXTR WOUND 2008; 7:204-9. [PMID: 19019846 DOI: 10.1177/1534734608326916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The effects of spermatheca gland extract of snail ( Telescopium telescopium) to promote wound healing were studied in an animal model. The spermatheca gland extract of the snail was used as a topical medicament to treat experimentally created full thickness wounds in 12 rabbits ( Oryctologous cuniculus). Wound healing was assessed on the basis of physical, histomorphological, and histochemical changes on days 0, 3, 7, and 14. Statistically significant differences were observed between the groups in all measured parameters. These exciting findings suggest that the data should be further tested in animal models to better understand the potential for wound healing in the spermatheca gland extract of the marine snail.
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Affiliation(s)
- Saurabh Kumar
- Department of Animal Husbandry, Thakurgangti, Jharkhand,
India
| | - Debaki Ghosh
- Departments of Veterinary Surgery and Radiology, West
Bengal University of Animal and Fishery Sciences
| | - Tuhin Kanti Biswas
- Department of Kayachikitsa, J. B. Roy State Ayurvedic
Medical College and Hospital Kolkata, India
| | - Uttam Dutta
- Department of Veterinary Gynecology and Obstetrics,
West Bengal University of Animal and Fishery Sciences
| | - Partho Das
- Department of Veterinary Anatomy and Histology, West
Bengal University of Animal and Fishery Sciences
| | - Subarna Kundu
- Departments of Veterinary Surgery and Radiology, West
Bengal University of Animal and Fishery Sciences
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Salvador C, Li B, Hansen R, Cramer DE, Kong M, Yan J. Yeast-derived beta-glucan augments the therapeutic efficacy mediated by anti-vascular endothelial growth factor monoclonal antibody in human carcinoma xenograft models. Clin Cancer Res 2008; 14:1239-47. [PMID: 18281559 DOI: 10.1158/1078-0432.ccr-07-1669] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
PURPOSE Bevacizumab is a recombinant IgG1 humanized monoclonal antibody against vascular endothelial growth factor (VEGF). Its proposed mechanism of action is independent of immune effector functions. Many human carcinomas not only secrete VEGF but also express membrane-bound VEGF. In addition, VEGF receptors are expressed on tumor cells. It is hypothesized that bevacizumab could bind membrane-bound VEGF or VEGF-VEGF receptor complexes on tumors, thereby initiating potential immunologic consequences. We previously showed that yeast-derived beta-glucan functions with antitumor antibodies that activate complement to recruit complement receptor 3-expressing leukocytes capable of mediating complement receptor 3-dependent cellular cytotoxicity of tumors opsonized with iC3b. In the current study, the therapeutic efficacy mediated by combining bevacizumab with yeast-derived beta-glucan was studied in human carcinoma xenograft models. EXPERIMENTAL DESIGN Human tumor cell lines were screened for membrane-bound VEGF expression both in vitro and in vivo. Complement activation mediated by bevacizumab was examined. Tumor cell lines positive or negative for membrane-bound VEGF expression were implanted in severe combined immunodeficient mice to establish xenograft models. Tumor-bearing mice were treated with different regimens. Tumor regression and long-term survival were recorded. RESULTS Human ovarian carcinoma SKOV-3 cells expressed membrane-bound VEGF both in vitro and in vivo. Bevacizumab was bound to membrane-bound VEGF, activated complement, and synergized with beta-glucan to elicit cellular cytotoxicity in vitro. In vivo study showed that beta-glucan could significantly augment the therapeutic efficacy mediated by bevacizumab. CONCLUSIONS Yeast-derived beta-glucan can synergize with anti-VEGF monoclonal antibody bevacizumab for the treatment of cancer with membrane-bound VEGF expression.
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Affiliation(s)
- Carolina Salvador
- Tumor Immunobiology Program of the James Graham Brown Cancer Center and Division of Hematology/Oncology, Department of Medicine, University of Louisville School of Medicine, Louisville, KY 40202, USA
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Lavigne LM, O'Brien XM, Kim M, Janowski JW, Albina JE, Reichner JS. Integrin engagement mediates the human polymorphonuclear leukocyte response to a fungal pathogen-associated molecular pattern. THE JOURNAL OF IMMUNOLOGY 2007; 178:7276-82. [PMID: 17513777 DOI: 10.4049/jimmunol.178.11.7276] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Extravasation of leukocytes from peripheral blood is required for an effective inflammatory response at sites of tissue infection. Integrins help mediate extravasation and navigate the leukocyte to the infectious source. A novel role for integrins in regulating the effector response to a cell wall component of fungal pathogens is the subject of the current study. Although phagocytosis is useful for clearance of unicellular fungi, the immune response against large, noningestible hyphae is not well-understood. Fungal beta-glucan, a pathogen-associated molecular pattern, activates production of superoxide anion in leukocytes without the need for phagocytosis. To model polymorphonuclear leukocyte (PMN) recognition of fungi under conditions in which phagocytosis cannot occur, beta-glucan was covalently immobilized onto tissue culture plastic. Plasma membrane-associated respiratory burst was measured by reduction of ferricytochrome C. Results show that the human PMN oxidative burst response to immobilized beta-glucan is suppressed by addition of beta(1) integrin ligands to the beta-glucan matrix. Suppression was dose dependent and steric hindrance was ruled out. beta(1) integrin ligands did not affect respiratory burst to ingestible beta-glucan-containing particles, phorbol esters or live yeast hyphae. Furthermore, in the absence of matrix, Ab activation of VLA3 or VLA5, but not other beta(1) integrins, also prevented beta-glucan-induced respiratory burst. beta(1)-induced suppression was blocked and burst response restored by treating neutrophils with either the cell-binding fragment of soluble human Fn, cyclic RGD peptide, or Ab specific to VLA3 or VLA5. Together these findings extend the functional role of beta(1) integrins to include modulating PMN respiratory burst to a pathogen-associated molecular pattern.
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Affiliation(s)
- Liz M Lavigne
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital and Brown University School of Medicine, Providence, RI 02903, USA
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Chen J, Seviour R. Medicinal importance of fungal beta-(1-->3), (1-->6)-glucans. ACTA ACUST UNITED AC 2007; 111:635-52. [PMID: 17590323 DOI: 10.1016/j.mycres.2007.02.011] [Citation(s) in RCA: 347] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 01/25/2007] [Accepted: 02/19/2007] [Indexed: 11/21/2022]
Abstract
Non-cellulosic beta-glucans are now recognized as potent immunological activators, and some are used clinically in China and Japan. These beta-glucans consist of a backbone of glucose residues linked by beta-(1-->3)-glycosidic bonds, often with attached side-chain glucose residues joined by beta-(1-->6) linkages. The frequency of branching varies. The literature suggests beta-glucans are effective in treating diseases like cancer, a range of microbial infections, hypercholesterolaemia, and diabetes. Their mechanisms of action involve them being recognized as non-self molecules, so the immune system is stimulated by their presence. Several receptors have been identified, which include: dectin-1, located on macrophages, which mediates beta-glucan activation of phagocytosis and production of cytokines, a response co-ordinated by the toll-like receptor-2. Activated complement receptors on natural killer cells, neutrophils, and lymphocytes, may also be associated with tumour cytotoxicity. Two other receptors, scavenger and lactosylceramide, bind beta-glucans and mediate a series of signal pathways leading to immunological activation. Structurally different beta-glucans appear to have different affinities toward these receptors and thus generate markedly different host responses. However, the published data are not always easy to interpret as many of the earlier studies used crude beta-glucan preparations with, for the most part, unknown chemical structures. Careful choice of beta-glucan products is essential if their benefits are to be optimized, and a better understanding of how beta-glucans bind to receptors should enable more efficient use of their biological activities.
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Affiliation(s)
- Jiezhong Chen
- Cancer Biology Program, Diamantia Institute for Cancer, Immunology and Metabolic Medicine, University of Queensland, Brisbane, Queensland 4102, Australia.
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Abstract
Dectin-1 is a natural killer (NK)-cell-receptor-like C-type lectin that is thought to be involved in innate immune responses to fungal pathogens. This transmembrane signalling receptor mediates various cellular functions, from fungal binding, uptake and killing, to inducing the production of cytokines and chemokines. These activities could influence the resultant immune response and can, in certain circumstances, lead to autoimmunity and disease. As I discuss here, understanding the molecular mechanisms behind these functions has revealed new concepts, including collaborative signalling with the Toll-like receptors (TLRs) and the use of spleen tyrosine kinase (SYK), that have implications for the role of other non-TLR pattern-recognition receptors in immunity.
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Affiliation(s)
- Gordon D Brown
- Institute of Infectious Disease and Molecular Medicine, CLS, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town, 7925, South Africa.
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Braun C, Hamacher J, Morel DR, Wendel A, Lucas R. Dichotomal role of TNF in experimental pulmonary edema reabsorption. THE JOURNAL OF IMMUNOLOGY 2005; 175:3402-8. [PMID: 16116234 DOI: 10.4049/jimmunol.175.5.3402] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Distinct from its receptor binding sites, TNF carries a lectin-like domain, situated at the tip of the molecule, which specifically binds oligosaccharides, such as N,N'-diacetylchitobiose. In view of the apparently conflicting data concerning TNF actions in pulmonary edema, we investigated the contribution of, on the one hand, the receptor binding sites and, in contrast, the lectin-like domain of the cytokine on pulmonary fluid reabsorption in in situ and in vivo flooded rat lungs. Receptor binding sites were blocked with the human soluble TNFR type 1 construct (sTNFR1), whereas the lectin-like domain was blunted with the oligosaccharide N,N'-diacetylchitobiose. We observed that in situ, TNF failed to stimulate alveolar liquid clearance, but did so together with the sTNFR1, and this activity was neutralized by N,N'-diacetylchitobiose. In vivo TNF inhibited liquid clearance, but activated it when complexed with the sTNFR1. A TNF-derived peptide mimic of the lectin-like domain activated fluid reabsorption in flooded lungs, and this activity was blunted by co-treatment with TNF. Our results thus indicate that in these models the receptor binding sites of TNF inhibit, whereas its lectin-like domain activates, edema reabsorption.
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Affiliation(s)
- Clemens Braun
- Department of Biochemical Pharmacology, University of Konstanz, Konstanz, Germany
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Abstract
The recognition of conserved microbial structures is a key aspect of metazoan immunity, and beta-glucans are emerging as a major target for the recognition of fungal pathogens. A number of receptors for these carbohydrates have been identified, which upon recognition, trigger a variety of immune responses. In contrast to many other systems, there is little apparent conservation in these mechanisms between vertebrates and invertebrates. In this review, we will highlight all the known receptors for beta-glucans and will discuss the various immune responses they can initiate, with reference to fungal infection, in both vertebrates and invertebrates.
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Affiliation(s)
- Gordon D Brown
- Institute of Infectious Disease and Molecular Medicine, CLS, Faculty of Health Sciences, University of Cape Town, Observatory, 7925, Cape Town, South Africa.
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