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Hatinguais R, Kay M, Salazar F, Conn DP, Williams DL, Cook PC, Willment JA, Brown GD. Development of Negative Controls for Fc-C-Type Lectin Receptor Probes. Microbiol Spectr 2023; 11:e0113523. [PMID: 37158741 PMCID: PMC10269840 DOI: 10.1128/spectrum.01135-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2023] [Accepted: 04/14/2023] [Indexed: 05/10/2023] Open
Abstract
Fc-C-type lectin receptor (Fc-CTLRs) probes are soluble chimeric proteins constituted of the extracellular domain of a CTLR fused with the constant fraction (Fc) of the human IgG. These probes are useful tools to study the interaction of CTLRs with their ligands, with applications similar to those of antibodies, often in combination with widely available fluorescent antibodies targeting the Fc fragment (anti-hFc). In particular, Fc-Dectin-1 has been extensively used to study the accessibility of β-glucans at the surface of pathogenic fungi. However, there is no universal negative control for Fc-CTLRs, making the distinction of specific versus nonspecific binding difficult. We describe here 2 negative controls for Fc-CTLRs: a Fc-control constituting of only the Fc portion, and a Fc-Dectin-1 mutant predicted to be unable to bind β-glucans. Using these new probes, we found that while Fc-CTLRs exhibit virtually no nonspecific binding to Candida albicans yeasts, Aspergillus fumigatus resting spores strongly bind Fc-CTLRs in a nonspecific manner. Nevertheless, using the controls we describe here, we were able to demonstrate that A. fumigatus spores expose a low amount of β-glucan. Our data highlight the necessity of appropriate negative controls for experiments involving Fc-CTLRs probes. IMPORTANCE While Fc-CTLRs probes are useful tools to study the interaction of CTLRs with ligands, their use is limited by the lack of appropriate negative controls in assays involving fungi and potentially other pathogens. We have developed and characterized 2 negative controls for Fc-CTLRs assays: Fc-control and a Fc-Dectin-1 mutant. In this manuscript, we characterize the use of these negative controls with zymosan, a β-glucan containing particle, and 2 human pathogenic fungi, Candida albicans yeasts and Aspergillus fumigatus conidia. We show that A. fumigatus conidia nonspecifically bind Fc-CTLRs probes, demonstrating the need for appropriate negative controls in such assays.
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Affiliation(s)
- Rémi Hatinguais
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Madalaine Kay
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Fabián Salazar
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Daniel P. Conn
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - David L. Williams
- Department of Surgery, James H. Quillen College of Medicine, Center for Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, Tennessee, USA
| | - Peter C. Cook
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
| | - Janet A. Willment
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Gordon D. Brown
- MRC Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
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Willment JA, Brown GD. Immunity to fungi: Editorial overview. Semin Immunol 2023; 66:101734. [PMID: 36842304 DOI: 10.1016/j.smim.2023.101734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- Janet A Willment
- MRC Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, United Kingdom.
| | - Gordon D Brown
- MRC Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, United Kingdom.
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3
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Hatinguais R, Willment JA, Brown GD. C-type lectin receptors in antifungal immunity: Current knowledge and future developments. Parasite Immunol 2023; 45:e12951. [PMID: 36114607 PMCID: PMC10078331 DOI: 10.1111/pim.12951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Revised: 09/05/2022] [Accepted: 09/12/2022] [Indexed: 01/31/2023]
Abstract
C-type lectin receptors (CLRs) constitute a category of innate immune receptors that play an essential role in the antifungal immune response. For over two decades, scientists have uncovered what are the fungal ligands recognized by CLRs and how these receptors initiate the immune response. Such studies have allowed the identification of genetic polymorphisms in genes encoding for CLRs or for proteins involved in the signalisation cascade they trigger. Nevertheless, our understanding of how these receptors functions and the full extent of their function during the antifungal immune response is still at its infancy. In this review, we summarize some of the main findings about CLRs in antifungal immunity and discuss what the future might hold for the field.
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Affiliation(s)
- Remi Hatinguais
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Janet A Willment
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Gordon D Brown
- MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
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Haji S, Ito T, Guenther C, Nakano M, Shimizu T, Mori D, Chiba Y, Tanaka M, Mishra SK, Willment JA, Brown GD, Nagae M, Yamasaki S. Human Dectin-1 is O-glycosylated and serves as a ligand for C-type lectin receptor CLEC-2. eLife 2022; 11:83037. [PMID: 36479973 PMCID: PMC9788829 DOI: 10.7554/elife.83037] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 12/07/2022] [Indexed: 12/13/2022] Open
Abstract
C-type lectin receptors (CLRs) elicit immune responses upon recognition of glycoconjugates present on pathogens and self-components. While Dectin-1 is the best-characterized CLR recognizing β-glucan on pathogens, the endogenous targets of Dectin-1 are not fully understood. Herein, we report that human Dectin-1 is a ligand for CLEC-2, another CLR expressed on platelets. Biochemical analyses revealed that Dectin-1 is a mucin-like protein as its stalk region is highly O-glycosylated. A sialylated core 1 glycan attached to the EDxxT motif of human Dectin-1, which is absent in mouse Dectin-1, provides a ligand moiety for CLEC-2. Strikingly, the expression of human Dectin-1 in mice rescued the lethality and lymphatic defect resulting from a deficiency of Podoplanin, a known CLEC-2 ligand. This finding is the first example of an innate immune receptor also functioning as a physiological ligand to regulate ontogeny upon glycosylation.
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Affiliation(s)
- Shojiro Haji
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan,Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka UniversityOsakaJapan
| | - Taiki Ito
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan,Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka UniversityOsakaJapan
| | - Carla Guenther
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan,Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka UniversityOsakaJapan
| | - Miyako Nakano
- Graduate School of Integrated Sciences for Life, Hiroshima UniversityHiroshimaJapan
| | - Takashi Shimizu
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan,Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka UniversityOsakaJapan
| | - Daiki Mori
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan,Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka UniversityOsakaJapan
| | - Yasunori Chiba
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST)TsukubaJapan
| | - Masato Tanaka
- Laboratory of Immune Regulation School of Life Sciences, Tokyo University of Pharmacy and Life SciencesHachiojiJapan
| | - Sushil K Mishra
- The Glycoscience Group, National University of Ireland, GalwayGalwayIreland
| | - Janet A Willment
- Medical Research Council Centre for Medical Mycology, University of ExeterExeterUnited Kingdom
| | - Gordon D Brown
- Medical Research Council Centre for Medical Mycology, University of ExeterExeterUnited Kingdom
| | - Masamichi Nagae
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan,Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka UniversityOsakaJapan
| | - Sho Yamasaki
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka UniversityOsakaJapan,Laboratory of Molecular Immunology, Immunology Frontier Research Center (IFReC), Osaka UniversityOsakaJapan,Center for Infectious Disease Education and Research (CiDER), Osaka UniversityOsakaJapan,Division of Molecular Design, Research Center for Systems Immunology, Medical Institute of Bioregulation, Kyushu UniversityFukuokaJapan
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Neves GWP, Wong SSW, Aimanianda V, Simenel C, Guijarro JI, Walls C, Willment JA, Gow NAR, Munro CA, Brown GD, Lopes-Bezerra LM. Complement-Mediated Differential Immune Response of Human Macrophages to Sporothrix Species Through Interaction With Their Cell Wall Peptidorhamnomannans. Front Immunol 2021; 12:749074. [PMID: 34867977 PMCID: PMC8636148 DOI: 10.3389/fimmu.2021.749074] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 10/25/2021] [Indexed: 12/23/2022] Open
Abstract
In this study, the human immune response mechanisms against Sporothrix brasiliensis and Sporothrix schenckii, two causative agents of human and animal sporotrichosis, were investigated. The interaction of S. brasiliensis and S. schenckii with human monocyte-derived macrophages (hMDMs) was shown to be dependent on the thermolabile serum complement protein C3, which facilitated the phagocytosis of Sporothrix yeast cells through opsonization. The peptidorhamnomannan (PRM) component of the cell walls of these two Sporothrix yeasts was found to be one of their surfaces exposed pathogen-associated molecular pattern (PAMP), leading to activation of the complement system and deposition of C3b on the Sporothrix yeast surfaces. PRM also showed direct interaction with CD11b, the specific component of the complement receptor-3 (CR3). Furthermore, the blockade of CR3 specifically impacted the interleukin (IL)-1β secretion by hMDM in response to both S. brasiliensis and S. schenckii, suggesting that the host complement system plays an essential role in the inflammatory immune response against these Sporothrix species. Nevertheless, the structural differences in the PRMs of the two Sporothrix species, as revealed by NMR, were related to the differences observed in the host complement activation pathways. Together, this work reports a new PAMP of the cell surface of pathogenic fungi playing a role through the activation of complement system and via CR3 receptor mediating an inflammatory response to Sporothrix species.
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Affiliation(s)
- Gabriela W. P. Neves
- Cell Biology Department, Rio de Janeiro State University, Rio de Janeiro, Brazil
| | | | | | - Catherine Simenel
- Institut Pasteur, Biological NMR and HDX-MS Technological Platform, CNRS UMR3528, Paris, France
| | - J. Iñaki Guijarro
- Institut Pasteur, Biological NMR and HDX-MS Technological Platform, CNRS UMR3528, Paris, France
| | - Catriona Walls
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Janet A. Willment
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Neil A. R. Gow
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Carol A. Munro
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Gordon D. Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Leila M. Lopes-Bezerra
- Cell Biology Department, Rio de Janeiro State University, Rio de Janeiro, Brazil,Biomedical Institute and Technology and Innovation Center (CIETEC), São Paulo University, São Paulo, Brazil,*Correspondence: Leila M. Lopes-Bezerra,
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6
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Willment JA. Fc-conjugated C-type lectin receptors: Tools for understanding host-pathogen interactions. Mol Microbiol 2021; 117:632-660. [PMID: 34709692 DOI: 10.1111/mmi.14837] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Accepted: 10/25/2021] [Indexed: 12/24/2022]
Abstract
The use of soluble fusion proteins of pattern recognition receptors (PRRs) used in the detection of exogenous and endogenous ligands has helped resolve the roles of PRRs in the innate immune response to pathogens, how they shape the adaptive immune response, and function in maintaining homeostasis. Using the immunoglobulin (Ig) crystallizable fragment (Fc) domain as a fusion partner, the PRR fusion proteins are soluble, stable, easily purified, have increased affinity due to the Fc homodimerization properties, and consequently have been used in a wide range of applications such as flow cytometry, screening of protein and glycan arrays, and immunofluorescent microscopy. This review will predominantly focus on the recognition of pathogens by the cell membrane-expressed glycan-binding proteins of the C-type lectin receptor (CLR) subgroup of PRRs. PRRs bind to conserved pathogen-associated molecular patterns (PAMPs), such as glycans, usually located within or on the outer surface of the pathogen. Significantly, many glycans structures are identical on both host and pathogen (e.g. the Lewis (Le) X glycan), allowing the use of Fc CLR fusion proteins with known endogenous and/or exogenous ligands as tools to identify pathogen structures that are able to interact with the immune system. Screens of highly purified pathogen-derived cell wall components have enabled identification of many unique PAMP structures recognized by CLRs. This review highlights studies using Fc CLR fusion proteins, with emphasis on the PAMPs found in fungi, bacteria, viruses, and parasites. The structure and unique features of the different CLR families is presented using examples from a broad range of microbes whenever possible.
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Affiliation(s)
- Janet A Willment
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, UK
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7
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Stappers MH, Nikolakopoulou C, Wiesner DL, Yuecel R, Klein BS, Willment JA, Brown GD. Characterization of antifungal C-type lectin receptor expression on murine epithelial and endothelial cells in mucosal tissues. Eur J Immunol 2021; 51:2341-2344. [PMID: 34114658 PMCID: PMC8593890 DOI: 10.1002/eji.202149192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/19/2021] [Accepted: 06/10/2021] [Indexed: 11/06/2022]
Abstract
Our data reveal that selection of enzymes for generating single cell suspensions from murine tissues influences detection of surface expression of antifungal CLRs. Using a method that most preserves receptor expression, we show that non-myeloid expression of antifungal CLRs is limited to MelLec on endothelial cells in murine mucosal tissues.
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Affiliation(s)
- Mark H.T. Stappers
- Aberdeen Fungal GroupInstitute of Medical SciencesUniversity of AberdeenAberdeenUK
- Department of BiosciencesMedical Research Council Centre for Medical Mycology at the University of ExeterExeterUK
| | - Christina Nikolakopoulou
- Aberdeen Fungal GroupInstitute of Medical SciencesUniversity of AberdeenAberdeenUK
- Department of BiosciencesMedical Research Council Centre for Medical Mycology at the University of ExeterExeterUK
| | - Darin L. Wiesner
- Department of PediatricsSchool of Medicine and Public HealthUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Raif Yuecel
- Iain Fraser Cytometry CentreInstitute of Medical SciencesUniversity of AberdeenAberdeenUK
- Exeter Centre for Cytomics (EXCC)Department of BiosciencesCollege of Life and Environmental SciencesUniversity of ExeterExeterEX4 4QDUK
| | - Bruce S. Klein
- Department of PediatricsSchool of Medicine and Public HealthUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Janet A. Willment
- Aberdeen Fungal GroupInstitute of Medical SciencesUniversity of AberdeenAberdeenUK
- Department of BiosciencesMedical Research Council Centre for Medical Mycology at the University of ExeterExeterUK
| | - Gordon D. Brown
- Aberdeen Fungal GroupInstitute of Medical SciencesUniversity of AberdeenAberdeenUK
- Department of BiosciencesMedical Research Council Centre for Medical Mycology at the University of ExeterExeterUK
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8
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Tone K, Stappers MHT, Hatinguais R, Dambuza IM, Salazar F, Wallace C, Yuecel R, Morvay PL, Kuwano K, Willment JA, Brown GD. MelLec Exacerbates the Pathogenesis of Aspergillus fumigatus-Induced Allergic Inflammation in Mice. Front Immunol 2021; 12:675702. [PMID: 34122436 PMCID: PMC8194280 DOI: 10.3389/fimmu.2021.675702] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Accepted: 05/04/2021] [Indexed: 11/30/2022] Open
Abstract
Environmental factors, particularly fungi, influence the pathogenesis of allergic airway inflammation, but the mechanisms underlying these effects are still unclear. Melanin is one fungal component which is thought to modulate pulmonary inflammation. We recently identified a novel C-type lectin receptor, MelLec (Clec1a), which recognizes fungal 1,8-dihydroxynaphthalene (DHN)-melanin and is able to regulate inflammatory responses. Here we show that MelLec promotes pulmonary allergic inflammation and drives the development of Th17 T-cells in response to spores of Aspergillus fumigatus. Unexpectedly, we found that MelLec deficiency was protective, with MelLec-/- animals showing normal weight gain and significantly reduced pulmonary inflammation in our allergic model. The lungs of treated MelLec-/- mice displayed significantly reduced inflammatory foci and reduced bronchial wall thickening, which correlated with a reduced cellular influx (particularly neutrophils and inflammatory monocytes) and levels of inflammatory cytokines and chemokines. Notably, fungal burdens were increased in MelLec-/- animals, without apparent adverse effects, and there were no alterations in the survival of these mice. Characterization of the pulmonary T-cell populations, revealed a significant reduction in Th17 cells, and no alterations in Th2, Th1 or Treg cells. Thus, our data reveal that while MelLec is required to control pulmonary fungal burden, the inflammatory responses mediated by this receptor negatively impact the animal welfare in this allergic model.
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Affiliation(s)
- Kazuya Tone
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Mark H. T. Stappers
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Remi Hatinguais
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Ivy M. Dambuza
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Fabián Salazar
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Carol Wallace
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Raif Yuecel
- Iain Fraser Cytometry Centre, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Exeter Centre for Cytomics (EXCC), Department of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Petruta L. Morvay
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Kazuyoshi Kuwano
- Division of Respiratory Diseases, Department of Internal Medicine, The Jikei University School of Medicine, Tokyo, Japan
| | - Janet A. Willment
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom
| | - Gordon D. Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Aberdeen, United Kingdom,Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, United Kingdom,*Correspondence: Gordon D. Brown,
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9
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Piras M, Patruno I, Nikolakopoulou C, Willment JA, Sloan NL, Zanato C, Brown GD, Zanda M. Synthesis of the Fungal Metabolite YWA1 and Related Constructs as Tools to Study MelLec-Mediated Immune Response to Aspergillus Infections†. J Org Chem 2021; 86:6044-6055. [PMID: 33884881 DOI: 10.1021/acs.joc.0c02324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe the chemical synthesis of the fungal naphthopyrones YWA1 and fonsecin B, as well as their functionalization with an amine-spacer arm and the conjugation of the resulting molecules to three different functional tags (i.e., biotin, Oregon green, 1-[3-(succinimidyloxycarbonyl)benzyl]-4-[5-(4-methoxyphenyl)-2-oxazolyl]pyridinium bromide (PyMPO)). The naphthopyrone-biotin and -PyMPO constructs maintained the ability to bind the C-type lectin receptor MelLec, whose interaction with immunologically active fungal metabolites (i.e., 1,8-dihydroxynaphthalene-(DHN)-melanin and YWA1) is a key step in host recognition and induction of protective immune responses against Aspergillus fumigatus. The fluorescent Fonsecin B-PyMPO construct 21 was used to selectively visualize MelLec-expressing cells, thus validating the potential of this strategy for studying the role and functions of MelLec in immunity.
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Affiliation(s)
- Monica Piras
- Kosterlitz Centre for Therapeutics, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, U.K
| | - Ilaria Patruno
- Kosterlitz Centre for Therapeutics, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, U.K
| | - Christina Nikolakopoulou
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, U.K.,Medical Research Council Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K
| | - Janet A Willment
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, U.K.,Medical Research Council Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K
| | - Nikki L Sloan
- Chemistry Department, Loughborough University, Loughborough LE113TU, U.K
| | - Chiara Zanato
- CY Cergy Paris Université, CNRS, BioCIS, 95000 Cergy Pontoise, France
| | - Gordon D Brown
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, U.K.,Medical Research Council Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, U.K
| | - Matteo Zanda
- Kosterlitz Centre for Therapeutics, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, U.K.,Chemistry Department, Loughborough University, Loughborough LE113TU, U.K.,C.N.R.-SCITEC, via Mancinelli 7, 20131 Milan, Italy
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Valsecchi I, Stephen-Victor E, Wong SSW, Karnam A, Sunde M, Guijarro JI, Rodríguez de Francisco B, Krüger T, Kniemeyer O, Brown GD, Willment JA, Latgé JP, Brakhage AA, Bayry J, Aimanianda V. The Role of RodA-Conserved Cysteine Residues in the Aspergillus fumigatus Conidial Surface Organization. J Fungi (Basel) 2020; 6:jof6030151. [PMID: 32859091 PMCID: PMC7558875 DOI: 10.3390/jof6030151] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 01/06/2023] Open
Abstract
Immune inertness of Aspergillusfumigatus conidia is attributed to its surface rodlet-layer made up of RodAp, characterized by eight conserved cysteine residues forming four disulfide bonds. Earlier, we showed that the conserved cysteine residue point (ccrp) mutations result in conidia devoid of the rodlet layer. Here, we extended our study comparing the surface organization and immunoreactivity of conidia carrying ccrp-mutations with the RODA deletion mutant (∆rodA). Western blot analysis using anti-RodAp antibodies indicated the absence of RodAp in the cytoplasm of ccrp-mutant conidia. Immunolabeling revealed differential reactivity to conidial surface glucans, the ccrp-mutant conidia preferentially binding to α-(1,3)-glucan, ∆rodA conidia selectively bound to β-(1,3)-glucan; the parental strain conidia showed negative labeling. However, permeability of ccrp-mutants and ∆rodA was similar to the parental strain conidia. Proteomic analyses of the conidial surface exposed proteins of the ccrp-mutants showed more similarities with the parental strain, but were significantly different from the ∆rodA. Ccrp-mutant conidia were less immunostimulatory compared to ∆rodA conidia. Our data suggest that (i) the conserved cysteine residues are essential for the trafficking of RodAp and the organization of the rodlet layer on the conidial surface, and (ii) targeted point mutation could be an alternative approach to study the role of fungal cell-wall genes in host–fungal interaction.
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Affiliation(s)
- Isabel Valsecchi
- Aspergillus Unit, Institut Pasteur, 75015 Paris, France; (I.V.); (J.-P.L.)
| | - Emmanuel Stephen-Victor
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherché des Cordeliers, Sorbonne Université, Université de Paris, 75006 Paris, France; (E.S.-V.); (A.K.)
| | - Sarah Sze Wah Wong
- Molecular Mycology Unit, Institut Pasteur, CNRS-UMR-2000, 10098 Paris, France;
| | - Anupama Karnam
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherché des Cordeliers, Sorbonne Université, Université de Paris, 75006 Paris, France; (E.S.-V.); (A.K.)
| | - Margaret Sunde
- School of Medical Sciences and Sydney Nano, University of Sydney, Sydney, New South Wales (NSW) 2006, Australia;
| | - J. Iñaki Guijarro
- Biological NMR Technological Platform, Institut Pasteur, CNRS-UMR-3528, 75015 Paris, France; (J.I.G.); (B.R.d.F.)
| | - Borja Rodríguez de Francisco
- Biological NMR Technological Platform, Institut Pasteur, CNRS-UMR-3528, 75015 Paris, France; (J.I.G.); (B.R.d.F.)
| | - Thomas Krüger
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany; (T.K.); (O.K.); (A.A.B.)
| | - Olaf Kniemeyer
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany; (T.K.); (O.K.); (A.A.B.)
| | - Gordon D. Brown
- Medical Research Council Centre for Medical Mycology (MRC CMM), University of Exeter, Exeter EX4 4QD, UK; (G.D.B.); (J.A.W.)
| | - Janet A. Willment
- Medical Research Council Centre for Medical Mycology (MRC CMM), University of Exeter, Exeter EX4 4QD, UK; (G.D.B.); (J.A.W.)
| | - Jean-Paul Latgé
- Aspergillus Unit, Institut Pasteur, 75015 Paris, France; (I.V.); (J.-P.L.)
| | - Axel A. Brakhage
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology, 07745 Jena, Germany; (T.K.); (O.K.); (A.A.B.)
- Institute of Microbiology, Friedrich Schiller University, 07745 Jena, Germany
| | - Jagadeesh Bayry
- Institut National de la Santé et de la Recherche Médicale, Centre de Recherché des Cordeliers, Sorbonne Université, Université de Paris, 75006 Paris, France; (E.S.-V.); (A.K.)
- Correspondence: (J.B.); (V.A.); Tel.: +33-1-44278203 (J.B.); +33-1-45688225 (V.A.)
| | - Vishukumar Aimanianda
- Molecular Mycology Unit, Institut Pasteur, CNRS-UMR-2000, 10098 Paris, France;
- Correspondence: (J.B.); (V.A.); Tel.: +33-1-44278203 (J.B.); +33-1-45688225 (V.A.)
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11
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Vendele I, Willment JA, Silva LM, Palma AS, Chai W, Liu Y, Feizi T, Spyrou M, Stappers MHT, Brown GD, Gow NAR. Mannan detecting C-type lectin receptor probes recognise immune epitopes with diverse chemical, spatial and phylogenetic heterogeneity in fungal cell walls. PLoS Pathog 2020; 16:e1007927. [PMID: 31999794 PMCID: PMC7012452 DOI: 10.1371/journal.ppat.1007927] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 02/11/2020] [Accepted: 12/22/2019] [Indexed: 01/09/2023] Open
Abstract
During the course of fungal infection, pathogen recognition by the innate immune system is critical to initiate efficient protective immune responses. The primary event that triggers immune responses is the binding of Pattern Recognition Receptors (PRRs), which are expressed at the surface of host immune cells, to Pathogen-Associated Molecular Patterns (PAMPs) located predominantly in the fungal cell wall. Most fungi have mannosylated PAMPs in their cell walls and these are recognized by a range of C-type lectin receptors (CTLs). However, the precise spatial distribution of the ligands that induce immune responses within the cell walls of fungi are not well defined. We used recombinant IgG Fc-CTLs fusions of three murine mannan detecting CTLs, including dectin-2, the mannose receptor (MR) carbohydrate recognition domains (CRDs) 4–7 (CRD4-7), and human DC-SIGN (hDC-SIGN) and of the β-1,3 glucan-binding lectin dectin-1 to map PRR ligands in the fungal cell wall of fungi grown in vitro in rich and minimal media. We show that epitopes of mannan-specific CTL receptors can be clustered or diffuse, superficial or buried in the inner cell wall. We demonstrate that PRR ligands do not correlate well with phylogenetic relationships between fungi, and that Fc-lectin binding discriminated between mannosides expressed on different cell morphologies of the same fungus. We also demonstrate CTL epitope differentiation during different phases of the growth cycle of Candida albicans and that MR and DC-SIGN labelled outer chain N-mannans whilst dectin-2 labelled core N-mannans displayed deeper in the cell wall. These immune receptor maps of fungal walls of in vitro grown cells therefore reveal remarkable spatial, temporal and chemical diversity, indicating that the triggering of immune recognition events originates from multiple physical origins at the fungal cell surface. Invasive fungal infections remain an important health problem in immunocompromised patients. Immune recognition of fungal pathogens involves binding of specific cell wall components by pathogen recognition receptors (PRRs) and subsequent activation of immune defences. Some cell wall components are conserved among fungal species while other components are species-specific and phenotypically diverse. The fungal cell wall is dynamic and capable of changing its composition and organization when adapting to different growth niches and environmental stresses. Differences in the composition of the cell wall lead to differential immune recognition by the host. Understanding how changes in the cell wall composition affect recognition by PRRs is likely to be of major diagnostic and clinical relevance. Here we address this fundamental question using four soluble immune receptor-probes which recognize mannans and β-glucan in the cell wall. We use this novel methodology to demonstrate that mannan epitopes are differentially distributed in the inner and outer layers of fungal cell wall in a clustered or diffuse manner. Immune reactivity of fungal cell surfaces was not correlated with relatedness of different fungal species, and mannan-detecting receptor-probes discriminated between cell surface mannans generated by the same fungus growing under different conditions. These studies demonstrate that mannan-epitopes on fungal cell surfaces are differentially distributed within and between the cell walls of fungal pathogens.
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Affiliation(s)
- Ingrida Vendele
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- Division of Infection and Immunity, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Janet A. Willment
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- School of Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, United Kingdom
| | - Lisete M. Silva
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Angelina S. Palma
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
- UCIBIO, Department of Chemistry, Faculty of Science and Technology, NOVA University of Lisbon, Lisbon, Portugal
| | - Wengang Chai
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Yan Liu
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Ten Feizi
- Glycosciences Laboratory, Department of Metabolism, Digestion and Reproduction, Imperial College London, London, United Kingdom
| | - Maria Spyrou
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- School of Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, United Kingdom
| | - Mark H. T. Stappers
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- School of Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, United Kingdom
| | - Gordon D. Brown
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- School of Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, United Kingdom
| | - Neil A. R. Gow
- MRC Centre for Medical Mycology, Aberdeen Fungal Group, College of Life Sciences and Medicine, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
- School of Biosciences, University of Exeter, Geoffrey Pope Building, Exeter, United Kingdom
- * E-mail:
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12
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Abstract
Fungi are opportunistic pathogens that infect immunocompromised patients and are responsible for an estimated 1.5 million deaths every year. The antifungal innate immune response is mediated through the recognition of pathogen-associated molecular patterns (PAMPs) by the host's pattern recognition receptors (PRRs). PRRs are immune receptors that ensure the internalisation and the killing of fungal pathogens. They also mount the inflammatory response, which contributes to initiate and polarise the adaptive response, controlled by lymphocytes. Both the innate and adaptive immune responses are required to control fungal infections. The immune recognition of fungal pathogen primarily occurs at the interface between the membrane of innate immune cells and the fungal cell wall, which contains a number of PAMPs. This chapter will focus on describing the main mammalian PRRs that have been shown to bind to PAMPs from the fungal cell wall of the four main fungal pathogens: Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans and Pneumocystis jirovecii. We will describe these receptors, their functions and ligands to provide the reader with an overview of how the immune system recognises fungal pathogens and responds to them.
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Affiliation(s)
- Remi Hatinguais
- MRC Centre for Medical Mycology at University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, UK
| | - Janet A Willment
- MRC Centre for Medical Mycology at University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, UK
| | - Gordon D Brown
- MRC Centre for Medical Mycology at University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, UK.
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13
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Tone K, Stappers MHT, Willment JA, Brown GD. C-type lectin receptors of the Dectin-1 cluster: Physiological roles and involvement in disease. Eur J Immunol 2019; 49:2127-2133. [PMID: 31580478 PMCID: PMC6916577 DOI: 10.1002/eji.201847536] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 08/12/2019] [Accepted: 09/27/2019] [Indexed: 12/27/2022]
Abstract
C-type lectin receptors (CLRs) are essential for multicellular existence, having diverse functions ranging from embryonic development to immune function. One subgroup of CLRs is the Dectin-1 cluster, comprising of seven receptors including MICL, CLEC-2, CLEC-12B, CLEC-9A, MelLec, Dectin-1, and LOX-1. Reflecting the larger CLR family, the Dectin-1 cluster of receptors has a broad range of ligands and functions, but importantly, is involved in numerous pathophysiological processes that regulate health and disease. Indeed, these receptors have been implicated in development, infection, regulation of inflammation, allergy, transplantation tolerance, cancer, cardiovascular disease, arthritis, and other autoimmune diseases. In this mini-review, we discuss the latest advancements in elucidating the function(s) of each of the Dectin-1 cluster CLRs, focussing on their physiological roles and involvement in disease.
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Affiliation(s)
- Kazuya Tone
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen, Scotland
| | - Mark H T Stappers
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, Devon, England
| | - Janet A Willment
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen, Scotland.,Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, Devon, England
| | - Gordon D Brown
- Aberdeen Fungal Group, University of Aberdeen, Institute of Medical Sciences, Aberdeen, Scotland.,Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, Devon, England
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14
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Brunel SF, Willment JA, Brown GD, Devereux G, Warris A. Aspergillus-induced superoxide production by cystic fibrosis phagocytes is associated with disease severity. ERJ Open Res 2018; 4:00068-2017. [PMID: 29651422 PMCID: PMC5890024 DOI: 10.1183/23120541.00068-2017] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 01/26/2018] [Indexed: 11/22/2022] Open
Abstract
Aspergillus fumigatus infects up to 50% of cystic fibrosis (CF) patients and may play a role in progressive lung disease. As cystic fibrosis transmembrane conductance regulator is expressed in cells of the innate immune system, we hypothesised that impaired antifungal immune responses play a role in CF-related Aspergillus lung disease. Peripheral blood mononuclear cells, polymorphonuclear cells (PMN) and monocytes were isolated from blood samples taken from CF patients and healthy volunteers. Live-cell imaging and colorimetric assays were used to assess antifungal activity in vitro. Production of reactive oxygen species (ROS) was measured using luminol-induced chemiluminescence and was related to clinical metrics as collected by case report forms. CF phagocytes are as effective as those from healthy controls with regards to phagocytosis, killing and restricting germination of A. fumigatus conidia. ROS production by CF phagocytes was up to four-fold greater than healthy controls (p<0.05). This effect could not be replicated in healthy phagocytes by priming with lipopolysaccharide or serum from CF donors. Increased production of ROS against A. fumigatus by CF PMN was associated with an increased number of clinical exacerbations in the previous year (p=0.007) and reduced lung function (by forced expiratory volume in 1 s) (p=0.014). CF phagocytes mount an intrinsic exaggerated release of ROS upon A. fumigatus stimulation which is associated with clinical disease severity. Excessive superoxide production by CF phagocytes against A. fumigatus is associated with clinical disease severityhttp://ow.ly/Elwy30i8mLe
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Affiliation(s)
- Shan F Brunel
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Janet A Willment
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Gordon D Brown
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Graham Devereux
- Cystic Fibrosis Clinic, Aberdeen Royal Infirmary, Aberdeen, UK
| | - Adilia Warris
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
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15
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Stappers MHT, Clark AE, Aimanianda V, Bidula S, Reid DM, Asamaphan P, Hardison SE, Dambuza IM, Valsecchi I, Kerscher B, Plato A, Wallace CA, Yuecel R, Hebecker B, da Glória Teixeira Sousa M, Cunha C, Liu Y, Feizi T, Brakhage AA, Kwon-Chung KJ, Gow NAR, Zanda M, Piras M, Zanato C, Jaeger M, Netea MG, van de Veerdonk FL, Lacerda JF, Campos A, Carvalho A, Willment JA, Latgé JP, Brown GD. Recognition of DHN-melanin by a C-type lectin receptor is required for immunity to Aspergillus. Nature 2018; 555:382-386. [PMID: 29489751 PMCID: PMC5857201 DOI: 10.1038/nature25974] [Citation(s) in RCA: 138] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Accepted: 02/06/2018] [Indexed: 01/04/2023]
Abstract
Our resistance to infection is critically dependent upon the ability of pattern recognition receptors to recognise microbial invasion and induce protective immune responses. One such family of receptors are the C-type lectins, which play central roles in antifungal immunity1. These receptors activate key effector mechanisms upon recognition of conserved fungal cell wall carbohydrates. However, several other immunologically active fungal ligands have been described, including melanin2,3, whose mechanisms of recognition remain largely undefined. Here we identify a C-type lectin receptor, Melanin sensing C-type Lectin receptor (MelLec), that plays an essential role in antifungal immunity through recognition of the naphthalene-diol unit of 1,8-dihydroxynaphthalene (DHN)-melanin. MelLec recognises melanin in conidial spores of Aspergillus fumigatus, as well as other DHN-melanised fungi and is ubiquitously expressed by CD31+ endothelial cells in mice. MelLec is also expressed by a sub-population of these cells in mice that co-express EpCAM and which were detected only in the lung and liver. In mouse models, MelLec was required for protection against disseminated infection with A. fumigatus. In humans, MelLec is also expressed by myeloid cells, and we identified a single nucleotide polymorphism of this receptor that negatively affected myeloid inflammatory responses and significantly increased susceptibility of stem-cell transplant recipients to disseminated Aspergillus infections. Thus MelLec is a receptor recognising an immunologically active component commonly found on fungi and plays an essential role in protective antifungal immunity in both mice and humans.
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Affiliation(s)
- Mark H T Stappers
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Alexandra E Clark
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | | | - Stefan Bidula
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Delyth M Reid
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Patawee Asamaphan
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Sarah E Hardison
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Ivy M Dambuza
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | | | - Bernhard Kerscher
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Anthony Plato
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Carol A Wallace
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Raif Yuecel
- Iain Fraser Cytometry Centre, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Betty Hebecker
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Maria da Glória Teixeira Sousa
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Cristina Cunha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Yan Liu
- Glycosciences Laboratory, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Ten Feizi
- Glycosciences Laboratory, Department of Medicine, Imperial College London, London W12 0NN, UK
| | - Axel A Brakhage
- Department of Microbiology and Molecular Biology, Leibniz Institute for Natural Product Research and Infection Biology (HKI), Friedrich Schiller University, D-07745 Jena, Germany
| | - Kyung J Kwon-Chung
- Molecular Microbiology Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Neil A R Gow
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Matteo Zanda
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Monica Piras
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Chiara Zanato
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Martin Jaeger
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Mihai G Netea
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Frank L van de Veerdonk
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen, The Netherlands
| | - João F Lacerda
- Instituto de Medicina Molecular, Faculdade de Medicina de Lisboa, Universidade de Lisboa, Lisboa, Portugal.,Serviço de Hematologia e Transplantação de Medula, Hospital de Santa Maria, Lisboa, Portugal
| | - António Campos
- Serviço de Transplantação de Medula Óssea (STMO), Instituto Português de Oncologia do Porto, Porto, Portugal
| | - Agostinho Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Janet A Willment
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
| | | | - Gordon D Brown
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen AB25 2ZD, UK
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16
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Kerscher B, Dambuza IM, Christofi M, Reid DM, Yamasaki S, Willment JA, Brown GD. Signalling through MyD88 drives surface expression of the mycobacterial receptors MCL (Clecsf8, Clec4d) and Mincle (Clec4e) following microbial stimulation. Microbes Infect 2016; 18:505-9. [PMID: 27005451 PMCID: PMC4936759 DOI: 10.1016/j.micinf.2016.03.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 02/29/2016] [Accepted: 03/13/2016] [Indexed: 02/06/2023]
Abstract
The heterodimeric mycobacterial receptors, macrophage C-type lectin (MCL) and macrophage inducible C-type lectin (Mincle), are upregulated at the cell surface following microbial challenge, but the mechanisms underlying this response are unclear. Here we report that microbial stimulation triggers Mincle expression through the myeloid differentiation primary response gene 88 (MyD88) pathway; a process that does not require MCL. Conversely, we show that MCL is constitutively expressed but retained intracellularly until Mincle is induced, whereupon the receptors form heterodimers which are translocated to the cell surface. Thus this "two-step" model for induction of these key receptors provides new insights into the underlying mechanisms of anti-mycobacterial immunity.
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Affiliation(s)
- Bernhard Kerscher
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Ivy M Dambuza
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Maria Christofi
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Delyth M Reid
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Sho Yamasaki
- Division of Molecular Immunology, Medical Institute of Bioregulation, Kyushu University, Japan
| | - Janet A Willment
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
| | - Gordon D Brown
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK.
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17
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Kerscher B, Wilson GJ, Reid DM, Mori D, Taylor JA, Besra GS, Yamasaki S, Willment JA, Brown GD. Mycobacterial receptor, Clec4d (CLECSF8, MCL), is coregulated with Mincle and upregulated on mouse myeloid cells following microbial challenge. Eur J Immunol 2015; 46:381-9. [PMID: 26558717 PMCID: PMC4833188 DOI: 10.1002/eji.201545858] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 09/15/2015] [Accepted: 11/06/2015] [Indexed: 11/25/2022]
Abstract
The C‐type lectin receptor (CTLR), Clec4d (MCL, CLECSF8), is a member of the Dectin‐2 cluster of CTLRs, which also includes the related receptors Mincle and Dectin‐2. Like Mincle, Clec4d recognizes mycobacterial cord factor, trehalose dimycolate, and we recently demonstrated its key role in anti‐mycobacterial immunity in mouse and man. Here, we characterized receptor expression in naïve mice, under inflammatory conditions, and during Mycobacterium bovis BCG infection using newly generated monoclonal antibodies. In naïve mice, Clec4d was predominantly expressed on myeloid cells within the peritoneal cavity, blood, and bone marrow. Unexpectedly, basal expression of Clec4d was very low on leukocytes in the lung. However, receptor expression was significantly upregulated on pulmonary myeloid cells during M. bovis BCG infection. Moreover, Clec4d expression could be strongly induced in vitro and in vivo by various microbial stimuli, including TLR agonists, but not exogenous cytokines. Notably, we show that Clec4d requires association with the signaling adaptor FcRγ and Mincle, but not Dectin‐2, for surface expression. In addition, we provide evidence that Clec4d and Mincle, but not Dectin‐2, are interdependently coregulated during inflammation and infection. These data show that Clec4d is an inducible myeloid‐expressed CTLR in mice, whose expression is tightly linked to that of Mincle.
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Affiliation(s)
- Bernhard Kerscher
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Gillian J Wilson
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Delyth M Reid
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Daiki Mori
- Division of Molecular Immunology, Medical Institute of Bioregulation, Kyushu University, Kyushu, Japan
| | - Julie A Taylor
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Birmingham, UK
| | - Sho Yamasaki
- Division of Molecular Immunology, Medical Institute of Bioregulation, Kyushu University, Kyushu, Japan
| | - Janet A Willment
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
| | - Gordon D Brown
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, UK
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18
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Wilson GJ, Marakalala MJ, Hoving JC, van Laarhoven A, Drummond RA, Kerscher B, Keeton R, van de Vosse E, Ottenhoff THM, Plantinga TS, Alisjahbana B, Govender D, Besra GS, Netea MG, Reid DM, Willment JA, Jacobs M, Yamasaki S, van Crevel R, Brown GD. The C-type lectin receptor CLECSF8/CLEC4D is a key component of anti-mycobacterial immunity. Cell Host Microbe 2015; 17:252-9. [PMID: 25674984 PMCID: PMC4334100 DOI: 10.1016/j.chom.2015.01.004] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2014] [Revised: 06/06/2014] [Accepted: 12/30/2014] [Indexed: 12/19/2022]
Abstract
The interaction of microbes with pattern recognition receptors (PRRs) is essential for protective immunity. While many PRRs that recognize mycobacteria have been identified, none is essentially required for host defense in vivo. Here, we have identified the C-type lectin receptor CLECSF8 (CLEC4D, MCL) as a key molecule in anti-mycobacterial host defense. Clecsf8−/− mice exhibit higher bacterial burdens and increased mortality upon M. tuberculosis infection. Additionally, Clecsf8 deficiency is associated with exacerbated pulmonary inflammation, characterized by enhanced neutrophil recruitment. Clecsf8−/− mice show reduced mycobacterial uptake by pulmonary leukocytes, but infection with opsonized bacteria can restore this phagocytic defect as well as decrease bacterial burdens. Notably, a CLECSF8 polymorphism identified in humans is associated with an increased susceptibility to pulmonary tuberculosis. We conclude that CLECSF8 plays a non-redundant role in anti-mycobacterial immunity in mouse and in man. Clecsf8 is required for anti-mycobacterial immunity Clecsf8 mediates non-opsonic mycobacterial recognition by pulmonary leukocytes Loss of Clecsf8 results in increased inflammation, bacterial burdens, and mortality A human CLECSF8 polymorphism is associated with increased susceptibility to TB
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Affiliation(s)
- Gillian J Wilson
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Mohlopheni J Marakalala
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, 792 Cape Town, South Africa
| | - Jennifer C Hoving
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, 792 Cape Town, South Africa
| | - Arjan van Laarhoven
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen 6525 GA, the Netherlands
| | - Rebecca A Drummond
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Bernhard Kerscher
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Roanne Keeton
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, 792 Cape Town, South Africa
| | - Esther van de Vosse
- Department of Infectious Diseases, Leiden University Medical Center, Leiden 2333 ZA, the Netherlands
| | - Tom H M Ottenhoff
- Department of Infectious Diseases, Leiden University Medical Center, Leiden 2333 ZA, the Netherlands
| | - Theo S Plantinga
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen 6525 GA, the Netherlands
| | | | - Dhirendra Govender
- Division of Anatomical Pathology, University of Cape Town, 7925 Cape Town, South Africa
| | - Gurdyal S Besra
- School of Biosciences, University of Birmingham, Birmingham B15 2TT, UK
| | - Mihai G Netea
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen 6525 GA, the Netherlands
| | - Delyth M Reid
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Janet A Willment
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Muazzam Jacobs
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, 792 Cape Town, South Africa
| | - Sho Yamasaki
- Division of Molecular Immunology, Medical Institute of Bioregulation, Kyushu University, Fukuoka 108-8639, Japan
| | - Reinout van Crevel
- Department of Internal Medicine, Radboud University Medical Center, Nijmegen 6525 GA, the Netherlands
| | - Gordon D Brown
- Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, UK; Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, 792 Cape Town, South Africa.
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19
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Redelinghuys P, Whitehead L, Augello A, Drummond RA, Levesque JM, Vautier S, Reid DM, Kerscher B, Taylor JA, Nigrovic PA, Wright J, Murray GI, Willment JA, Hocking LJ, Fernandes MJG, De Bari C, Mcinnes IB, Brown GD. MICL controls inflammation in rheumatoid arthritis. Ann Rheum Dis 2015; 75:1386-91. [PMID: 26275430 PMCID: PMC4941174 DOI: 10.1136/annrheumdis-2014-206644] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 07/24/2015] [Indexed: 12/29/2022]
Abstract
BACKGROUND Myeloid inhibitory C-type lectin-like receptor (MICL, Clec12A) is a C-type lectin receptor (CLR) expressed predominantly by myeloid cells. Previous studies have suggested that MICL is involved in controlling inflammation. OBJECTIVE To determine the role of this CLR in inflammatory pathology using Clec12A(-/-) mice. METHODS Clec12A(-/-) mice were generated commercially and primarily characterised using the collagen antibody-induced arthritis (CAIA) model. Mechanisms and progress of disease were characterised by clinical scoring, histology, flow cytometry, irradiation bone-marrow chimera generation, administration of blocking antibodies and in vivo imaging. Characterisation of MICL in patients with rheumatoid arthritis (RA) was determined by immunohistochemistry and single nucleotide polymorphism analysis. Anti-MICL antibodies were detected in patient serum by ELISA and dot-blot analysis. RESULTS MICL-deficient animals did not present with pan-immune dysfunction, but exhibited markedly exacerbated inflammation during CAIA, owing to the inappropriate activation of myeloid cells. Polymorphisms of MICL were not associated with disease in patients with RA, but this CLR was the target of autoantibodies in a subset of patients with RA. In wild-type mice the administration of such antibodies recapitulated the Clec12A(-/-) phenotype. CONCLUSIONS MICL plays an essential role in regulating inflammation during arthritis and is an autoantigen in a subset of patients with RA. These data suggest an entirely new mechanism underlying RA pathogenesis, whereby the threshold of myeloid cell activation can be modulated by autoantibodies that bind to cell membrane-expressed inhibitory receptors.
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Affiliation(s)
| | - Lauren Whitehead
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Andrea Augello
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | | | - Jean-Michel Levesque
- Faculty of Medicine, Department of Microbiology, Infectious Diseases, and Immunology, Laval University, Quebec, Canada
| | - Simon Vautier
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Delyth M Reid
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | | | - Julie A Taylor
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Peter A Nigrovic
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - John Wright
- Department of Orthopedic Surgery, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Graeme I Murray
- Division of Applied Medicine, Department of Pathology, University of Aberdeen, Aberdeen, UK
| | - Janet A Willment
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Lynne J Hocking
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Maria J G Fernandes
- Faculty of Medicine, Department of Microbiology, Infectious Diseases, and Immunology, Laval University, Quebec, Canada
| | - Cosimo De Bari
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
| | - Iain B Mcinnes
- Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, UK
| | - Gordon D Brown
- Institute of Medical Sciences, University of Aberdeen, Aberdeen, UK
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20
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Abstract
New discoveries reveal crucial roles for the Dectin-2 family in many aspects of the immune response. Myeloid and non-myeloid cells express members of the C-type lectin-like receptor (CTLR) family, which mediate crucial cellular functions during immunity and homeostasis. Of relevance here is the dendritic cell-associated C-type lectin-2 (Dectin-2) family of CTLRs, which includes blood dendritic cell antigen 2 (BDCA-2), dendritic cell immunoactivating receptor (DCAR), dendritic cell immunoreceptor (DCIR), Dectin-2, C-type lectin superfamily 8 (CLECSF8) and macrophage-inducible C-type lectin (Mincle). These CTLRs possess a single extracellular conserved C-type lectin-like domain and are capable of mediating intracellular signalling either directly, through integral signalling domains, or indirectly, by associating with signalling adaptor molecules. These receptors recognize a diverse range of endogenous and exogenous ligands, and can function as pattern recognition receptors for several classes of pathogens including fungi, bacteria and parasites, driving both innate and adaptive immunity. In this review, we summarize our knowledge of each of these receptors, highlighting the exciting discoveries that have been made in recent years.
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Affiliation(s)
- Bernhard Kerscher
- Aberdeen Fungal Group, Section of Immunity and Infection, Institute of Medical Sciences, University of Aberdeen, Ashgrove Road West, Aberdeen AB25 2ZD, UK
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21
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Abstract
Innate immunity is constructed around genetically encoded receptors that survey the intracellular and extracellular environments for signs of invading microorganisms. These receptors recognise the invader and through complex intracellular networks of molecular signaling, they destroy the threat whilst instructing effective adaptive immune responses. Many of these receptors, like the Toll-like receptors in particular, are well-known for their ability to mediate downstream responses upon recognition of exogenous or endogenous ligands; however, the emerging family known as the C-type lectin-like receptors contains many members that have a huge impact on immune and homeostatic regulation. Of particular interest here are the C-type lectin-like receptors that make up the Dectin-1 cluster and their intracellular signaling motifs that mediate their functions. In this review, we aim to draw together current knowledge of ligands, motifs and signaling pathways, present downstream of Dectin-1 cluster receptors, and discuss how these dictate their role within biological systems.
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Affiliation(s)
- Anthony Plato
- Aberdeen Fungal Group, Section of Immunology and Infection, University of Aberdeen, Aberdeen, UK
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22
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Graham LM, Gupta V, Schafer G, Reid DM, Kimberg M, Dennehy KM, Hornsell WG, Guler R, Campanero-Rhodes MA, Palma AS, Feizi T, Kim SK, Sobieszczuk P, Willment JA, Brown GD. The C-type lectin receptor CLECSF8 (CLEC4D) is expressed by myeloid cells and triggers cellular activation through Syk kinase. J Biol Chem 2012; 287:25964-74. [PMID: 22689578 PMCID: PMC3406680 DOI: 10.1074/jbc.m112.384164] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
CLECSF8 is a poorly characterized member of the "Dectin-2 cluster" of C-type lectin receptors and was originally thought to be expressed exclusively by macrophages. We show here that CLECSF8 is primarily expressed by peripheral blood neutrophils and monocytes and weakly by several subsets of peripheral blood dendritic cells. However, expression of this receptor is lost upon in vitro differentiation of monocytes into dendritic cells or macrophages. Like the other members of the Dectin-2 family, which require association of their transmembrane domains with signaling adaptors for surface expression, CLECSF8 is retained intracellularly when expressed in non-myeloid cells. However, we demonstrate that CLECSF8 does not associate with any known signaling adaptor molecule, including DAP10, DAP12, or the FcRγ chain, and we found that the C-type lectin domain of CLECSF8 was responsible for its intracellular retention. Although CLECSF8 does not contain a signaling motif in its cytoplasmic domain, we show that this receptor is capable of inducing signaling via Syk kinase in myeloid cells and that it can induce phagocytosis, proinflammatory cytokine production, and the respiratory burst. These data therefore indicate that CLECSF8 functions as an activation receptor on myeloid cells and associates with a novel adaptor molecule. Characterization of the CLECSF8-deficient mice and screening for ligands using oligosaccharide microarrays did not provide further insights into the physiological function of this receptor.
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Affiliation(s)
- Lisa M Graham
- Institute of Infectious Disease and Molecular Medicine, Central Laboratory Services, Faculty of Health Sciences, University of Cape Town, Observatory, Cape Town 7925, South Africa
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23
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Faro-Trindade I, Willment JA, Kerrigan AM, Redelinghuys P, Hadebe S, Reid DM, Srinivasan N, Wainwright H, Lang DM, Steele C, Brown GD. Characterisation of innate fungal recognition in the lung. PLoS One 2012; 7:e35675. [PMID: 22536422 PMCID: PMC3334970 DOI: 10.1371/journal.pone.0035675] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2012] [Accepted: 03/19/2012] [Indexed: 11/24/2022] Open
Abstract
The innate recognition of fungi by leukocytes is mediated by pattern recognition receptors (PRR), such as Dectin-1, and is thought to occur at the cell surface triggering intracellular signalling cascades which lead to the induction of protective host responses. In the lung, this recognition is aided by surfactant which also serves to maintain the balance between inflammation and pulmonary function, although the underlying mechanisms are unknown. Here we have explored pulmonary innate recognition of a variety of fungal particles, including zymosan, Candida albicans and Aspergillus fumigatus, and demonstrate that opsonisation with surfactant components can limit inflammation by reducing host-cell fungal interactions. However, we found that this opsonisation does not contribute directly to innate fungal recognition and that this process is mediated through non-opsonic PRRs, including Dectin-1. Moreover, we found that pulmonary inflammatory responses to resting Aspergillus conidia were initiated by these PRRs in acidified phagolysosomes, following the uptake of fungal particles by leukocytes. Our data therefore provides crucial new insights into the mechanisms by which surfactant can maintain pulmonary function in the face of microbial challenge, and defines the phagolysosome as a novel intracellular compartment involved in the innate sensing of extracellular pathogens in the lung.
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Affiliation(s)
- Inês Faro-Trindade
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
| | - Janet A. Willment
- Aberdeen Fungal Group, Section of Immunology and Infection, Division of Applied Medicine, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, United Kingdom
| | - Ann M. Kerrigan
- Aberdeen Fungal Group, Section of Immunology and Infection, Division of Applied Medicine, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, United Kingdom
| | - Pierre Redelinghuys
- Aberdeen Fungal Group, Section of Immunology and Infection, Division of Applied Medicine, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, United Kingdom
| | - Sabelo Hadebe
- Aberdeen Fungal Group, Section of Immunology and Infection, Division of Applied Medicine, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, United Kingdom
| | - Delyth M. Reid
- Aberdeen Fungal Group, Section of Immunology and Infection, Division of Applied Medicine, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, United Kingdom
| | - Naren Srinivasan
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
| | - Helen Wainwright
- Division of Anatomical Pathology, University of Cape Town, Observatory, South Africa
| | - Dirk M. Lang
- Department of Human Biology, University of Cape Town, Observatory, South Africa
| | - Chad Steele
- Department of Medicine, University of Alabama, Birmingham, Alabama, United States of America
| | - Gordon D. Brown
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, South Africa
- Aberdeen Fungal Group, Section of Immunology and Infection, Division of Applied Medicine, Institute of Medical Sciences, Foresterhill, University of Aberdeen, Aberdeen, United Kingdom
- * E-mail:
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24
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Kerrigan AM, Navarro-Nuñez L, Pyz E, Finney BA, Willment JA, Watson SP, Brown GD. Podoplanin-expressing inflammatory macrophages activate murine platelets via CLEC-2. J Thromb Haemost 2012; 10:484-6. [PMID: 22212362 PMCID: PMC3433653 DOI: 10.1111/j.1538-7836.2011.04614.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 12/15/2011] [Indexed: 11/29/2022]
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25
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Ferwerda B, Ferwerda G, Plantinga TS, Willment JA, van Spriel AB, Venselaar H, Elbers CC, Johnson MD, Cambi A, Huysamen C, Jacobs L, Jansen T, Verheijen K, Masthoff L, Morré SA, Vriend G, Williams DL, Perfect JR, Joosten LAB, Wijmenga C, van der Meer JWM, Adema GJ, Kullberg BJ, Brown GD, Netea MG. Human dectin-1 deficiency and mucocutaneous fungal infections. N Engl J Med 2009; 361:1760-7. [PMID: 19864674 PMCID: PMC2773015 DOI: 10.1056/nejmoa0901053] [Citation(s) in RCA: 553] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mucocutaneous fungal infections are typically found in patients who have no known immune defects. We describe a family in which four women who were affected by either recurrent vulvovaginal candidiasis or onychomycosis had the early-stop-codon mutation Tyr238X in the beta-glucan receptor dectin-1. The mutated form of dectin-1 was poorly expressed, did not mediate beta-glucan binding, and led to defective production of cytokines (interleukin-17, tumor necrosis factor, and interleukin-6) after stimulation with beta-glucan or Candida albicans. In contrast, fungal phagocytosis and fungal killing were normal in the patients, explaining why dectin-1 deficiency was not associated with invasive fungal infections and highlighting the specific role of dectin-1 in human mucosal antifungal defense.
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Affiliation(s)
- Bart Ferwerda
- Department of Internal Medicine and the Nijmegen Institute for Infection, Inflammation, and Immunity, Radboud University Nijmegen, Nijmegen, The Netherlands
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26
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Dennehy KM, Willment JA, Williams DL, Brown GD. Reciprocal regulation of IL-23 and IL-12 following co-activation of Dectin-1 and TLR signaling pathways. Eur J Immunol 2009; 39:1379-86. [PMID: 19291703 PMCID: PMC2720084 DOI: 10.1002/eji.200838543] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Recognition of microbial products by germ-line-encoded PRR initiates immune responses, but how PRR mediate specific host responses to infectious agents is poorly understood. We and others have proposed that specificity is achieved by collaborative responses mediated between different PRR. One such example comprises the fungal beta-glucan receptor Dectin-1, which collaborates with TLR to induce TNF production. We show here that collaborative responses mediated by Dectin-1 and TLR2 are more extensive than first appreciated, and result in enhanced IL-23, IL-6 and IL-10 production in DC, while down-regulating IL-12 relative to the levels produced by TLR ligation alone. Such down-regulation occurred with multiple MyD88-coupled TLR, was dependent on signaling through Dectin-1 and also occurred in macrophages. These findings explain how fungi can induce IL-23 and IL-6, while suppressing IL-12, a combination which has previously been shown to contribute to the development of Th17 responses found during fungal infections. Furthermore, these data reveal how the collaboration of different PRR can tailor specific responses to infectious agents.
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Affiliation(s)
- Kevin M Dennehy
- Institute of Infectious Disease and Molecular Medicine, Clinical Laboratory Sciences Division of Immunology, University of Cape Town, Cape Town, South Africa
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27
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Kerrigan AM, Dennehy KM, Mourão-Sá D, Faro-Trindade I, Willment JA, Taylor PR, Eble JA, Reis e Sousa C, Brown GD. CLEC-2 is a phagocytic activation receptor expressed on murine peripheral blood neutrophils. J Immunol 2009; 182:4150-7. [PMID: 19299712 DOI: 10.4049/jimmunol.0802808] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CLEC-2 is a member of the "dectin-1 cluster" of C-type lectin-like receptors and was originally thought to be restricted to platelets. In this study, we demonstrate that murine CLEC-2 is also expressed by peripheral blood neutrophils, but only weakly by bone marrow or elicited inflammatory neutrophils. On circulating neutrophils, CLEC-2 can mediate phagocytosis of Ab-coated beads and the production of proinflammatory cytokines, including TNF-alpha, in response to the CLEC-2 ligand, rhodocytin. CLEC-2 possesses a tyrosine-based cytoplasmic motif similar to that of dectin-1, and we show using chimeric analyses that the activities of this receptor are dependent on this tyrosine. Like dectin-1, CLEC-2 can recruit the signaling kinase Syk in myeloid cells, however, stimulation of this pathway does not induce the respiratory burst. These data therefore demonstrate that CLEC-2 expression is not restricted to platelets and that it functions as an activation receptor on neutrophils.
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Affiliation(s)
- Ann M Kerrigan
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, South Africa
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28
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Huysamen C, Willment JA, Dennehy KM, Brown GD. CLEC9A is a novel activation C-type lectin-like receptor expressed on BDCA3+ dendritic cells and a subset of monocytes. J Biol Chem 2008; 283:16693-701. [PMID: 18408006 PMCID: PMC2562446 DOI: 10.1074/jbc.m709923200] [Citation(s) in RCA: 239] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
We describe here the first characterization of CLEC9A, a group V C-type lectin-like receptor located in the “Dectin-1 cluster” of related receptors, which are encoded within the natural killer (NK)-gene complex. Expression of human CLEC9A is highly restricted in peripheral blood, being detected only on BDCA3+ dendritic cells and on a small subset of CD14+CD16- monocytes. CLEC9A is expressed at the cell surface as a glycosylated dimer and can mediate endocytosis, but not phagocytosis. CLEC9A possesses a cytoplasmic immunoreceptor tyrosine-based activation-like motif that can recruit Syk kinase, and we demonstrate, using receptor chimeras, that this receptor can induce proinflammatory cytokine production. These data indicate that CLEC9A functions as an activation receptor.
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Affiliation(s)
- Cristal Huysamen
- Division of Immunology, Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, 7925, South Africa
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29
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Dennehy KM, Ferwerda G, Faro-Trindade I, Pyz E, Willment JA, Taylor PR, Kerrigan A, Tsoni SV, Gordon S, Meyer-Wentrup F, Adema GJ, Kullberg BJ, Schweighoffer E, Tybulewicz V, Mora-Montes HM, Gow NAR, Williams DL, Netea MG, Brown GD. Syk kinase is required for collaborative cytokine production induced through Dectin-1 and Toll-like receptors. Eur J Immunol 2008; 38:500-6. [PMID: 18200499 PMCID: PMC2430329 DOI: 10.1002/eji.200737741] [Citation(s) in RCA: 292] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2007] [Revised: 10/17/2007] [Accepted: 12/13/2007] [Indexed: 01/15/2023]
Abstract
Recognition of microbial components by germ-line encoded pattern recognition receptors (PRR) initiates immune responses to infectious agents. We and others have proposed that pairs or sets of PRR mediate host immunity. One such pair comprises the fungal beta-glucan receptor, Dectin-1, which collaborates through an undefined mechanism with Toll-like receptor 2 (TLR2) to induce optimal cytokine responses in macrophages. We show here that Dectin-1 signaling through the spleen tyrosine kinase (Syk) pathway is required for this collaboration, which can also occur with TLR4, 5, 7 and 9. Deficiency of either Syk or the TLR adaptor MyD88 abolished collaborative responses, which include TNF, MIP-1alpha and MIP-2 production, and which are comparable to the previously described synergy between TLR2 and TLR4. Collaboration of the Syk and TLR/MyD88 pathways results in sustained degradation of the inhibitor of kappaB (IkappaB), enhancing NFkappaB nuclear translocation. These findings establish the first example of Syk- and MyD88-coupled PRR collaboration, further supporting the concept that paired receptors collaborate to control infectious agents.
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Affiliation(s)
- Kevin M Dennehy
- Institute of Infectious Disease and Molecular Medicine, Clinical Laboratory Sciences Division of Immunology, University of Cape Town, Cape Town, South Africa
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30
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Willment JA, Martin DP, Palmer KE, Schnippenkoetter WH, Shepherd DN, Rybicki EP. Identification of long intergenic region sequences involved in maize streak virus replication. J Gen Virol 2007; 88:1831-1841. [PMID: 17485545 DOI: 10.1099/vir.0.82513-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The main cis-acting control regions for replication of the single-stranded DNA genome of maize streak virus (MSV) are believed to reside within an approximately 310 nt long intergenic region (LIR). However, neither the minimum LIR sequence required nor the sequence determinants of replication specificity have been determined experimentally. There are iterated sequences, or iterons, both within the conserved inverted-repeat sequences with the potential to form a stem-loop structure at the origin of virion-strand replication, and upstream of the rep gene TATA box (the rep-proximal iteron or RPI). Based on experimental analyses of similar iterons in viruses from other geminivirus genera and their proximity to known Rep-binding sites in the distantly related mastrevirus wheat dwarf virus, it has been hypothesized that the iterons may be Rep-binding and/or -recognition sequences. Here, a series of LIR deletion mutants was used to define the upper bounds of the LIR sequence required for replication. After identifying MSV strains and distinct mastreviruses with incompatible replication-specificity determinants (RSDs), LIR chimaeras were used to map the primary MSV RSD to a 67 nt sequence containing the RPI. Although the results generally support the prevailing hypothesis that MSV iterons are functional analogues of those found in other geminivirus genera, it is demonstrated that neither the inverted-repeat nor RPI sequences are absolute determinants of replication specificity. Moreover, widely divergent mastreviruses can trans-replicate one another. These results also suggest that sequences in the 67 nt region surrounding the RPI interact in a sequence-specific manner with those of the inverted repeat.
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Affiliation(s)
- Janet A Willment
- Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Darrin P Martin
- Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
| | - Kenneth E Palmer
- Department of Pharmacology and Toxicology, University of Louisville, 570 South Preston Street, Louisville, KY 40202, USA
- James Graham Brown Cancer Center, University of Louisville, 529 South Jackson Street, Louisville, KY 40202, USA
| | | | - Dionne N Shepherd
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa
| | - Edward P Rybicki
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Rondebosch, Cape Town 7701, South Africa
- Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Observatory 7925, South Africa
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31
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Abstract
Human polymorphonuclear leukocytes (PMN) are a first line of defense against fungal infections. PMN express numerous pattern recognition receptors (PRR) that facilitate identification of invading microorganisms and ultimately promote resolution of disease. Dectin-1 (beta-glucan receptor) is a PRR expressed on several cell types and has been studied on monocytes and macrophages. However, the role played by dectin-1 in the recognition and killing of fungi by PMN is unknown. We investigated the ability of dectin-1 to mediate human PMN phagocytosis and fungicidal activity. Dectin-1 was expressed on the surface of PMN from all subjects tested (n=29) and in an intracellular compartment that co-sedimented with azurophilic granules in Percoll density gradients. Soluble beta-glucan and mAb GE2 (anti-dectin-1) inhibited binding and phagocytosis of zymosan by human PMN (e.g., ingestion was inhibited 40.1% by 30 min, p<0.001), and blocked reactive oxygen species production. Notably, soluble beta-glucan and GE2 inhibited phagocytosis and killing of Candida albicans by PMN (inhibition of killing was 54.8% for beta-glucan and 36.2% for GE2, p<0.01). Our results reveal a mechanism whereby PMN dectin-1 plays a key role in the recognition and killing of fungal pathogens by the innate immune system.
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Affiliation(s)
- Adam D Kennedy
- Laboratory of Human Bacterial Pathogenesis, Rocky Mountain Laboratories, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Hamilton, MT 59840, USA
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32
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Taylor PR, Tsoni SV, Willment JA, Dennehy KM, Rosas M, Findon H, Haynes K, Steele C, Botto M, Gordon S, Brown GD. Dectin-1 is required for beta-glucan recognition and control of fungal infection. Nat Immunol 2006; 8:31-8. [PMID: 17159984 PMCID: PMC1888731 DOI: 10.1038/ni1408] [Citation(s) in RCA: 869] [Impact Index Per Article: 48.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2006] [Accepted: 10/11/2006] [Indexed: 12/19/2022]
Abstract
Beta-glucan is one of the most abundant polysaccharides in fungal pathogens, yet its importance in antifungal immunity is unclear. Here we show that deficiency of dectin-1, the myeloid receptor for beta-glucan, rendered mice susceptible to infection with Candida albicans. Dectin-1-deficient leukocytes demonstrated significantly impaired responses to fungi even in the presence of opsonins. Impaired leukocyte responses were manifested in vivo by reduced inflammatory cell recruitment after fungal infection, resulting in substantially increased fungal burdens and enhanced fungal dissemination. Our results establish a fundamental function for beta-glucan recognition by dectin-1 in antifungal immunity and demonstrate a signaling non-Toll-like pattern-recognition receptor required for the induction of protective immune responses.
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Affiliation(s)
- Philip R Taylor
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX13RE, UK
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33
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Marshall ASJ, Willment JA, Pyz E, Dennehy KM, Reid DM, Dri P, Gordon S, Wong SYC, Brown GD. Human MICL (CLEC12A) is differentially glycosylated and is down-regulated following cellular activation. Eur J Immunol 2006; 36:2159-69. [PMID: 16838277 DOI: 10.1002/eji.200535628] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
C-type lectins are the most diverse and prevalent lectin family in immunity. Particular interest has recently been attracted by the C-type lectin-like receptors on NK cells, which appear to regulate the activation/inhibitory balance of these cells, controlling cytotoxicity and cytokine production. We previously identified a human C-type lectin-like receptor, closely related to both the beta-glucan receptor and the lectin-like receptor for oxidized-LDL, named MICL (myeloid inhibitory C-type lectin-like receptor), which we had shown using chimeric analysis to function as an inhibitory receptor. Using a novel MICL-specific monoclonal antibody, we show here that human MICL is expressed primarily on myeloid cells, including granulocytes, monocytes, macrophages, and dendritic cells. Although MICL was highly N-glycosylated in primary cells, the level of glycosylation was found to vary between cell types. MICL surface expression was down-regulated during inflammatory/activation conditions in vitro, as well as during an in vivo model of acute inflammation, which we characterize here. This suggests that human MICL may be involved in the control of myeloid cell activation during inflammation.
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34
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Graham LM, Tsoni SV, Willment JA, Williams DL, Taylor PR, Gordon S, Dennehy K, Brown GD. Soluble Dectin-1 as a tool to detect beta-glucans. J Immunol Methods 2006; 314:164-9. [PMID: 16844139 DOI: 10.1016/j.jim.2006.05.013] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2006] [Revised: 05/15/2006] [Accepted: 05/17/2006] [Indexed: 10/24/2022]
Abstract
Beta-glucans are structural components of fungal cell walls which are involved in the immune recognition of fungal pathogens and possess beneficial immunomodulatory activities in isolated form. Here we have developed a soluble chimeric form of the major mammalian beta-glucan receptor, Dectin-1, and demonstrate its application for the detection and characterisation of soluble and insoluble beta-glucans, including fungal particles, using ELISA, flow cytometric and fluorescence-based microscopy assays.
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Affiliation(s)
- Lisa M Graham
- 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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35
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Heinsbroek SEM, Taylor PR, Rosas M, Willment JA, Williams DL, Gordon S, Brown GD. Expression of Functionally Different Dectin-1 Isoforms by Murine Macrophages. J Immunol 2006; 176:5513-8. [PMID: 16622020 DOI: 10.4049/jimmunol.176.9.5513] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dectin-1 is a specific receptor for beta-glucans and a major receptor for fungal particles on macrophages (Mphi). It is a type II membrane receptor that has a C-terminal, NK-like, C-type lectin-like domain separated from the cell membrane by a short stalk region and a cytoplasmic immunoreceptor tyrosine-based activation-like motif. We observed functional differences in dectin-1-dependent recognition of fungal particles by Mphi from different mouse strains. RT-PCR analysis revealed that mice have at least two splice forms of dectin-1, generated by differential usage of exon 3, encoding the full-length dectin-1A and a stalkless Mphi dectin-1B. Mphi from BALB/c mice and genetically related mice expressed both isoforms in similar amounts, whereas Mphi from C57BL/6 and related mice mainly expressed the smaller isoform. NIH-3T3 fibroblast and RAW264.7 macrophage cell lines stably expressing either isoform were able to bind and phagocytose zymosan at 37 degrees C. However, binding by the smaller dectin-1B isoform was significantly affected at lower temperatures. These properties were shared by the equivalent human isoforms. The relative ability of each of the isoforms to induce TNF-alpha production in RAW264.7 Mphi was also found to be different. These results are the first evidence that dectin-1 isoforms are functionally distinct and indicate that differential isoform usage may represent a mechanism of regulating cellular responses to beta-glucans.
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36
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Willment JA, Marshall ASJ, Reid DM, Williams DL, Wong SYC, Gordon S, Brown GD. The human ?-glucan receptor is widely expressed and functionally equivalent to murine Dectin-1 on primary cells. Eur J Immunol 2005; 35:1539-47. [PMID: 15816015 DOI: 10.1002/eji.200425725] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We identified the C-type-lectin-like receptor, Dectin-1, as the major receptor for fungal beta-glucans on murine macrophages and have demonstrated that it plays a significant role in the cellular response to these carbohydrates. Using two novel, isoform-specific mAb, we show here that human Dectin-1, the beta-glucan receptor (betaGR), is widely expressed and present on all monocyte populations as well as macrophages, DC, neutrophils and eosinophils. This receptor is also expressed on B cells and a subpopulation of T cells, demonstrating that human Dectin-1 is not myeloid restricted. Both major functional betaGR isoforms - betaGR-A and betaGR-B - were expressed by these cell populations in peripheral blood; however, only betaGR-B was significantly expressed on mature monocyte-derived macrophages and immature DC, suggesting cell-specific control of isoform expression. Inflammatory cells, recruited in vivo using a new skin-window technique, demonstrated that Dectin-1 expression was not significantly modulated on macrophages during inflammation, but is decreased on recruited granulocytes. Despite previous reports detailing the involvement of other beta-glucan receptors on mature human macrophages, we have demonstrated that Dectin-1 acted as the major beta-glucan receptor on these cells and contributed to the inflammatory response to these carbohydrates.
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Affiliation(s)
- Janet A Willment
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK
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37
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Abstract
beta-Glucans are structural components of fungal cell walls, which have a stimulatory effect on the immune system. Although a number of receptors for these carbohydrates have been proposed, the recently identified C-type lectin-like receptor, Dectin-1, appears to play a central role. Dectin-1 is expressed on phagocytic cells, including macrophages and neutrophils, and mediates both the internalization and cellular responses to beta-glucan, through unique mechanisms. Dectin-1 can recognize and respond to live fungal pathogens and is being increasingly appreciated as having a key role in the innate responses to these pathogens. In addition to its exogenous ligands, Dectin-1 can recognize an unidentified endogenous ligand on T cells and may act as a co-stimulatory molecule, although its function in these responses is less clear. This review will highlight the current knowledge of Dectin-1 and its potential role in antifungal immunity, as well as deficiencies in our understanding.
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Affiliation(s)
- Jurgen Herre
- Sir William Dunn School of Pathology, University of Oxford, UK
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38
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Willment JA, Lin HH, Reid DM, Taylor PR, Williams DL, Wong SYC, Gordon S, Brown GD. Dectin-1 expression and function are enhanced on alternatively activated and GM-CSF-treated macrophages and are negatively regulated by IL-10, dexamethasone, and lipopolysaccharide. J Immunol 2004; 171:4569-73. [PMID: 14568930 DOI: 10.4049/jimmunol.171.9.4569] [Citation(s) in RCA: 194] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Dectin-1 is the major macrophage receptor for beta-glucans and generates a proinflammatory response through the recognition of these carbohydrates on fungal pathogens. We have examined the effects of cytokines and other agents on the expression and functions of dectin-1 in both resident and elicited murine peritoneal macrophages (Mphi). Dectin-1 expression was found to be highly up-regulated by GM-CSF and by the cytokines that induce alternative macrophage activation, IL-4 and IL-13. In contrast, IL-10, LPS, and dexamethasone, but not IFN-gamma, down-regulated the expression of this receptor. Modulation of dectin-1 receptor levels correlated with the ability of these macrophages to bind zymosan and significantly affected the contribution of this receptor to the resultant proinflammatory response, as measured by the production of TNF-alpha, although some Mphi-specific differences were observed. These results correlate with the known effects of these cytokines and other agents on the ability of the immune system to recognize and respond to fungal pathogens.
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Affiliation(s)
- Janet A Willment
- Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom
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39
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Marshall ASJ, Willment JA, Lin HH, Williams DL, Gordon S, Brown GD. Identification and characterization of a novel human myeloid inhibitory C-type lectin-like receptor (MICL) that is predominantly expressed on granulocytes and monocytes. J Biol Chem 2004; 279:14792-802. [PMID: 14739280 DOI: 10.1074/jbc.m313127200] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Inhibitory and activatory C-type lectin-like receptors play an important role in immunity through the regulation of leukocytes. Here, we report the identification and characterization of a novel myeloid inhibitory C-type lectin-like receptor (MICL) whose expression is primarily restricted to granulocytes and monocytes. This receptor, which contains a single C-type lectin-like domain and a cytoplasmic immunoreceptor tyrosine-based inhibitory motif, is related to LOX-1 (lectin-like receptor for oxidized low density lipoprotein-1) and the beta-glucan receptor (Dectin-1) and is variably spliced and highly N-glycosylated. We demonstrate that it preferentially associates with the signaling phosphatases SHP-1 and SHP-2, but not with SHIP. Novel chimeric analyses with a construct combining MICL and the beta-glucan receptor show that MICL can inhibit cellular activation through its cytoplasmic immunoreceptor tyrosine-based inhibitory motif. These data suggest that MICL is a negative regulator of granulocyte and monocyte function.
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MESH Headings
- Alternative Splicing
- Amino Acid Motifs
- Amino Acid Sequence
- Animals
- Base Sequence
- Blotting, Northern
- CHO Cells
- Cell Line
- Cloning, Molecular
- Cricetinae
- Cytoplasm/metabolism
- Glycosylation
- Granulocytes/metabolism
- Humans
- Lectins, C-Type
- Mice
- Models, Biological
- Molecular Sequence Data
- Monocytes/metabolism
- NIH 3T3 Cells
- Phylogeny
- Precipitin Tests
- Protein Binding
- Protein Structure, Tertiary
- RNA/chemistry
- RNA, Messenger/metabolism
- Rats
- Receptors, LDL/chemistry
- Receptors, Mitogen/chemistry
- Receptors, Mitogen/metabolism
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Homology, Amino Acid
- Signal Transduction
- Spectrometry, Fluorescence
- Tissue Distribution
- Transfection
- Tumor Necrosis Factor-alpha/metabolism
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Affiliation(s)
- Andrew S J Marshall
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
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40
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Taylor PR, Brown GD, Herre J, Williams DL, Willment JA, Gordon S. The Role of SIGNR1 and the β-Glucan Receptor (Dectin-1) in the Nonopsonic Recognition of Yeast by Specific Macrophages. J Immunol 2004; 172:1157-62. [PMID: 14707091 DOI: 10.4049/jimmunol.172.2.1157] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We recently demonstrated that the beta-glucan receptor Dectin-1 (betaGR) was the major nonopsonic beta-glucan receptor on macrophages (Mphi) for the yeast-derived particle zymosan. However, on resident peritoneal Mphi, we identified an additional mannan-inhibitable receptor for zymosan that was distinct from the Mphi mannose receptor (MR). In this study, we have studied the mannose-binding potential of murine Mphi and identified the dendritic cell-specific ICAM-3-grabbing nonintegrin homolog, SIGN-related 1 (SIGNR1), as a major MR on murine resident peritoneal Mphi. Both SIGNR1 and betaGR cooperated in the nonopsonic recognition of zymosan by these Mphi. When SIGNR1 was introduced into NIH3T3 fibroblasts or RAW 264.7 Mphi, it conferred marked zymosan-binding potential on these cells. However, in the nonprofessional phagocytes (NIH3T3), SIGNR1 was found to be poorly phagocytic, suggesting that other receptors such as betaGR may play a more dominant role in particle internalization on professional phagocytes. Binding of zymosan to RAW 264.7 Mphi expressing SIGNR1 resulted in TNF-alpha production. Treatment of RAW 264.7 Mphi expressing SIGNR1, which express low levels of betaGR, with beta-glucans had little effect on binding or TNF-alpha production, indicating that there was no absolute requirement for betaGR in this process. These studies have identified SIGNR1 as a major MR for fungal and other pathogens present on specific subsets of Mphi.
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MESH Headings
- Animals
- Binding Sites/immunology
- Candida albicans/immunology
- Candida albicans/metabolism
- Cell Adhesion Molecules/biosynthesis
- Cell Adhesion Molecules/physiology
- Cell Line
- Cells, Cultured
- Lectins, C-Type/biosynthesis
- Lectins, C-Type/metabolism
- Lectins, C-Type/physiology
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Mannose/metabolism
- Mannose Receptor
- Mannose-Binding Lectins/metabolism
- Membrane Proteins/biosynthesis
- Membrane Proteins/physiology
- Mice
- Mice, Inbred BALB C
- Mice, Inbred C57BL
- NIH 3T3 Cells
- Nerve Tissue Proteins/biosynthesis
- Nerve Tissue Proteins/physiology
- Opsonin Proteins/metabolism
- Phagocytosis/immunology
- Receptors, Cell Surface/biosynthesis
- Receptors, Cell Surface/metabolism
- Receptors, Cell Surface/physiology
- Receptors, Immunologic/biosynthesis
- Receptors, Immunologic/physiology
- Transduction, Genetic
- Tumor Necrosis Factor-alpha/biosynthesis
- Zymosan/metabolism
- Zymosan/pharmacology
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Affiliation(s)
- Philip R Taylor
- Sir William Dunn School of Pathology, Oxford University, South Parks Road, Oxford OX1 3RE, United Kingdom.
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41
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Abstract
The ability of fungal-derived beta-glucan particles to induce leukocyte activation and the production of inflammatory mediators, such as tumor necrosis factor (TNF)-alpha, is a well characterized phenomenon. Although efforts have been made to understand how these carbohydrate polymers exert their immunomodulatory effects, the receptors involved in generating these responses are unknown. Here we show that Dectin-1 mediates the production of TNF-alpha in response to zymosan and live fungal pathogens, an activity that occurs at the cell surface and requires the cytoplasmic tail and immunoreceptor tyrosine activation motif of Dectin-1 as well as Toll-like receptor (TLR)-2 and Myd88. This is the first demonstration that the inflammatory response to pathogens requires recognition by a specific receptor in addition to the TLRs. Furthermore, these studies implicate Dectin-1 in the production of TNF-alpha in response to fungi, a critical step required for the successful control of these pathogens.
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Affiliation(s)
- Gordon D Brown
- Sir William Dunn School of Pathology, South Parks Road, Oxford OX1 3RE, United Kingdom.
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42
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Taylor PR, Brown GD, Reid DM, Willment JA, Martinez-Pomares L, Gordon S, Wong SYC. The beta-glucan receptor, dectin-1, is predominantly expressed on the surface of cells of the monocyte/macrophage and neutrophil lineages. J Immunol 2002; 169:3876-82. [PMID: 12244185 DOI: 10.4049/jimmunol.169.7.3876] [Citation(s) in RCA: 476] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We recently identified dectin-1 (betaGR) as a major beta-glucan receptor on leukocytes and demonstrated that it played a significant role in the non-opsonic recognition of soluble and particulate beta-glucans. Using a novel mAb (2A11) raised against betaGR, we show here that the receptor is not dendritic cell-restricted as first reported, but is broadly expressed, with highest surface expression on populations of myeloid cells (monocyte/macrophage (Mphi) and neutrophil lineages). Dendritic cells and a subpopulation of T cells also expressed the betaGR, but at lower levels. Alveolar Mphi, like inflammatory Mphi, exhibited the highest surface expression of betaGR, indicative of a role for this receptor in immune surveillance. In contrast, resident peritoneal Mphi expressed much lower levels of betaGR on the cell surface. Characterization of the nonopsonic recognition of zymosan by resident peritoneal Mphi suggested the existence of an additional beta-glucan-independent mechanism of zymosan binding that was not observed on elicited or bone marrow-derived Mphi. Although this recognition could be inhibited by mannan, we were able to exclude involvement of the Mphi mannose receptor and complement receptor 3 in this process. These observations imply the existence of an additional mannan-dependent receptor involved in the recognition of zymosan by resident peritoneal Mphi.
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MESH Headings
- 3T3 Cells
- Animals
- Ascitic Fluid/immunology
- Ascitic Fluid/metabolism
- Ascitic Fluid/pathology
- Bone Marrow Cells/immunology
- Bone Marrow Cells/metabolism
- Cell Line
- Cell Lineage/genetics
- Cell Lineage/immunology
- Cell Membrane/genetics
- Cell Membrane/immunology
- Cell Membrane/metabolism
- Glucans/metabolism
- Lectins, C-Type
- Leukemia P388
- Macrophages, Alveolar/immunology
- Macrophages, Alveolar/metabolism
- Macrophages, Peritoneal/immunology
- Macrophages, Peritoneal/metabolism
- Membrane Proteins/biosynthesis
- Membrane Proteins/blood
- Membrane Proteins/genetics
- Mice
- Mice, Inbred C57BL
- Monocytes/immunology
- Monocytes/metabolism
- Myeloid Cells/immunology
- Myeloid Cells/metabolism
- Nerve Tissue Proteins/biosynthesis
- Nerve Tissue Proteins/blood
- Nerve Tissue Proteins/genetics
- Neutrophils/immunology
- Neutrophils/metabolism
- Opsonin Proteins/metabolism
- Organ Specificity/genetics
- Organ Specificity/immunology
- RNA, Messenger/biosynthesis
- Receptors, Immunologic/biosynthesis
- Receptors, Immunologic/blood
- Receptors, Immunologic/genetics
- Spleen/cytology
- Spleen/immunology
- Spleen/metabolism
- Zymosan/metabolism
- beta-Glucans
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Affiliation(s)
- Philip R Taylor
- Sir William Dunn School of Pathology, Oxford University, Oxford, United Kingdom
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43
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Abstract
Zymosan is a beta-glucan- and mannan-rich particle that is widely used as a cellular activator for examining the numerous responses effected by phagocytes. The macrophage mannose receptor (MR) and complement receptor 3 (CR3) have historically been considered the major macrophage lectins involved in the nonopsonic recognition of these yeast-derived particles. Using specific carbohydrate inhibitors, we show that a beta-glucan receptor, but not the MR, is a predominant receptor involved in this process. Furthermore, nonopsonic zymosan binding was unaffected by genetic CD11b deficiency or a blocking monoclonal antibody (mAb) against CR3, demonstrating that CR3 was not the beta-glucan receptor mediating this activity. To address the role of the recently described beta-glucan receptor, Dectin-1, we generated a novel anti-Dectin-1 mAb, 2A11. Using this mAb, we show here that Dectin-1 was almost exclusively responsible for the beta-glucan-dependent, nonopsonic recognition of zymosan by primary macro-phages. These findings define Dectin-1 as the leukocyte beta-glucan receptor, first described over 50 years ago, and resolves the long-standing controversy regarding the identity of this important molecule. Furthermore, these results identify Dectin-1 as a new target for examining the immunomodulatory properties of beta-glucans for therapeutic drug design.
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Affiliation(s)
- Gordon D Brown
- Sir William Dunn School of Pathology, University of Oxford, United Kingdom.
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44
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Willment JA, Martin DP, Van der Walt E, Rybicki EP. Biological and Genomic Sequence Characterization of Maize streak virus Isolates from Wheat. Phytopathology 2002; 92:81-86. [PMID: 18944143 DOI: 10.1094/phyto.2002.92.1.81] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT Maize streak virus (MSV) is best known as the causal agent of maize streak disease. However, only a genetically uniform subset of the viruses within this diverse species is actually capable of producing severe symptoms in maize. Whereas these "maize-type" viruses all share greater than 95% sequence identity, MSV strains isolated from grasses may share as little as 79% sequence identity with the maize-type viruses. Here, we present the complete genome sequences and biological characterization of two MSV isolates from wheat that share approximately 89% sequence identity with the maize-type viruses. Clonal populations of these two isolates, named MSV-Tas and MSV-VW, were leafhopper-transmitted to Digitaria sanguinalis and a range of maize, wheat, and barley genotypes. Whereas the two viruses showed some differences in their pathogenicity in maize, they were both equally pathogenic in D. sanguinalis and the various wheat and barley genotypes tested. Phylogenetic analyses involving the genome sequences of MSV-Tas and MSV-VW, a new maize-type virus also fully sequenced in this study (MSV-VM), and all other available African streak virus sequences, indicated that MSV-Tas and MSV-VW are close relatives that together represent a distinct MSV strain. Sequence analyses revealed that MSV-VM has a recombinant genome containing MSV-Tas/VW-like sequences within its movement protein gene.
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45
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Abstract
Recombination between divergent virus genomes is believed to be a major mechanism for generation of novel virus genotypes. We have examined the recombination process in geminiviruses by forcing recombination between two distinct isolates of Maize streak virus (MSV), MSV-Kom and MSV-Set. Heterodimeric agroinfectious constructs containing tandemly cloned mixtures of complete or partial MSV-Set and MSV-Kom genomes were used to simulate a circular dimeric form similar to that which would be expected to occur following a single intermolecular crossing-over event between MSV-Set and MSV-Kom replicative form DNAs at the long intergenic region (LIR)-movement protein gene (MP) interface. We isolated, analysed and biologically characterized many of the recombinant MSV genomes that were generated from the constructs in planta. Apart from having the same simulated breakpoint at the LIR-MP interface, all the genomes examined had a second breakpoint that had been generated through either intramolecular homologous recombination or a replicational release mechanism. The pathogenicities of six predominantly MSV-Kom-like recombinants were tested in maize. While all were capable of producing a symptomatic infection in this host, none was more virulent than MSV-Kom and only two were more virulent than MSV-Set. The two most virulent recombinants were leafhopper transmitted to a range of differentially MSV-resistant maize, wheat and barley genotypes and both were found to have unique biological properties.
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Affiliation(s)
- W H Schnippenkoetter
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Cape Town 7000, South Africa1
| | - D P Martin
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Cape Town 7000, South Africa1
| | - J A Willment
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Cape Town 7000, South Africa1
| | - E P Rybicki
- Department of Molecular and Cell Biology, University of Cape Town, Private Bag, Cape Town 7000, South Africa1
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46
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Abstract
beta-1,3-d-Glucans are biological response modifiers with potent effects on the immune system. A number of receptors are thought to play a role in mediating these responses, including murine Dectin-1, which we recently identified as a beta-glucan receptor. In this study we describe the characterization of the human homologue of this receptor and show that it is structurally and functionally similar to the mouse receptor. The human beta-glucan receptor is a type II transmembrane receptor with a single extracellular carbohydrate recognition domain and an immunoreceptor tyrosine activation motif in its cytoplasmic tail. The human beta-glucan receptor is widely expressed and functions as a pattern recognition receptor, recognizing a variety of beta-1,3- and/or beta-1,6-linked glucans as well as intact yeast. In contrast to the murine receptor, the human receptor mRNA is alternatively spliced, resulting in two major (A and B) and six minor isoforms. The two major isoforms differ by the presence of a stalk region separating the carbohydrate recognition domain from the transmembrane region and are the only isoforms that are functional for beta-glucan binding. The human receptor also binds T-lymphocytes at a site distinct from the beta-glucan binding site, indicating that this receptor can recognize both endogenous and exogenous ligands.
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Affiliation(s)
- J A Willment
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford, OX1 3RE, United Kingdom
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47
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Martin DP, Willment JA, Billharz R, Velders R, Odhiambo B, Njuguna J, James D, Rybicki EP. Sequence diversity and virulence in Zea mays of Maize streak virus isolates. Virology 2001; 288:247-55. [PMID: 11601896 DOI: 10.1006/viro.2001.1075] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Full genomic sequences were determined for 12 Maize streak virus (MSV) isolates obtained from Zea mays and wild grass species. These and 10 other publicly available full-length sequences were used to classify a total of 66 additional MSV isolates that had been characterized by PCR-restriction fragment length polymorphism and/or partial nucleotide sequence analysis. A description is given of the host and geographical distribution of the MSV strain and subtype groupings identified. The relationship between the genotypes of 21 fully sequenced virus isolates and their virulence in differentially MSV-resistant Z. mays genotypes was examined. Within the only MSV strain grouping that produced severe symptoms in maize, highly virulent and widely distributed genotypes were identified that are likely to pose the most serious threat to maize production in Africa. Evidence is presented that certain of the isolates investigated may be the products of either intra- or interspecific recombination.
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Affiliation(s)
- D P Martin
- Department of Moleculare Cell Biology, University of Cape Town, Cape Town, South Africa, 7701
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48
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Schnippenkoetter WH, Martin DP, Hughes FL, Fyvie M, Willment JA, James D, von Wechmar MB, Rybicki EP. The relative infectivities and genomic characterisation of three distinct mastreviruses from South Africa. Arch Virol 2001; 146:1075-88. [PMID: 11504417 DOI: 10.1007/s007050170107] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The genomic nucleotide sequences of the cloned agroinfectious genomes of three South African mastreviruses obtained from Zea mays, a Setaria sp., and Panicum maximum (designated MSV-Kom, MSV-Set, and PanSV-Kar respectively), were determined. Additionally, their relative infectivities and virulence were analysed in a range of differentially susceptible wheat, maize, and barley genotypes. MSV-Kom produced moderate to severe streak symptoms in all maize genotypes tested, but only moderate to very mild symptoms in the wheat and barley genotypes. MSV-Set infected only the susceptible to tolerant maize genotypes, but was generally more severe in the barley and wheat genotypes than MSV-Kom. PanSV-Kar was incapable of infecting any of the wheat and barley genotypes and only produced very mild symptoms on the three most sensitive maize genotypes. Genomic characteristics in common with related mastreviruses were identified. Phylogenetic analysis indicated that while MSV-Kom was closely related to previously sequenced MSV isolates, MSV-Set and PanSV-Kar represented distinctly novel strains of MSV and PanSV respectively. In the case of MSV-Set, this is the most distantly related MSV strain yet characterised.
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Affiliation(s)
- W H Schnippenkoetter
- Department of Microbiology, University of Cape Town, Rondebosch, Western Cape, South Africa
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Abstract
Maize streak virus (MSV) is the most economically significant member of a diverse group of African grass-infecting Mastrevirus species in the family Geminiviridae. We designed a single set of degenerate primers which enables the PCR amplification of an approximately 1300 bp DNA fragment spanning both conserved (the RepA gene) and variable (the long intergenic region and MP gene) portions of these viruses' genomes. Using restriction fragment length polymorphism (RFLP) analysis of PCR products obtained from 39 MSV, one SSV, and two PanSV isolates, it was possible to both identify the different virus species, which differ in nucleotide sequence by up to 40%, and to differentiate between MSV isolates sharing up to 99% sequence identity. The reliability of the RFLP data for typing the MSV isolates was verified by the phylogenetic analysis of the partial genomic nucleotide sequences of a representative subset of the MSV isolates. Based on both the RFLP and sequence data, the MSV isolates could be clearly differentiated into the four groups: these were a group of predominantly maize-infecting isolates, and three groups containing grass/wheat-infecting isolates. RFLP analysis also revealed a number of mixed virus infections in which, in certain instances, it was possible to identify individual population members.
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Affiliation(s)
- J A Willment
- Department of Microbiology, University of Cape Town, Private Bag, Rondebosch 7701, Western Cape, South Africa
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Martin DP, Willment JA, Rybicki EP. Evaluation of Maize Streak Virus Pathogenicity in Differentially Resistant Zea mays Genotypes. Phytopathology 1999; 89:695-700. [PMID: 18944683 DOI: 10.1094/phyto.1999.89.8.695] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
ABSTRACT We devised a rapid technique for the objective and precise assessment of both the pathogenicity of maize streak virus (MSV) isolates and the MSV resistance of maize genotypes. The technique involves the use of agroinoculation to infect maize seedlings and the objective symptom evaluation by quantification of infection rates, stunting, and chlorotic leaf areas. In assessing the MSV resistance of 19 maize genotypes, we describe how the use of differentially virulent virus isolates enables the analysis of MSV resistance phenotypes, ranging from extremely susceptible to completely immune. We further demonstrate how quantification of chlorotic leaf areas by image analysis permits differentiation between degrees of MSV resistance that are indistinguishable from one another using currently employed symptom assessment approaches. Using chlorotic area measurements, we quantify the virulence of a diverse group of 10 MSV isolates and, through agroinoculation of differentially susceptible maize genotypes, we demonstrate the use of our technique in evaluating the pathogenicity of these isolates.
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