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Holder A, Kolakowski J, Rosentreter C, Knuepfer E, Jégouzo SAF, Rosenwasser O, Harris H, Baumgaertel L, Gibson A, Werling D. Characterisation of the bovine C-type lectin receptor Mincle and potential evidence for an endogenous ligand. Front Immunol 2023; 14:1189587. [PMID: 37275870 PMCID: PMC10235688 DOI: 10.3389/fimmu.2023.1189587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Accepted: 05/09/2023] [Indexed: 06/07/2023] Open
Abstract
Innate immune receptors that form complexes with secondary receptors, activating multiple signalling pathways, modulate cellular activation and play essential roles in regulating homeostasis and immunity. We have previously identified a variety of bovine C-type lectin-like receptors that possess similar functionality than their human orthologues. Mincle (CLEC4E), a heavily glycosylated monomer, is involved in the recognition of the mycobacterial component Cord factor (trehalose 6,6'-dimycolate). Here we characterise the bovine homologue of Mincle (boMincle), and demonstrate that the receptor is structurally and functionally similar to the human orthologue (huMincle), although there are some notable differences. In the absence of cross-reacting antibodies, boMincle-specific antibodies were created and used to demonstrate that, like the human receptor, boMincle is predominantly expressed by myeloid cells. BoMincle surface expression increases during the maturation of monocytes to macrophages. However, boMincle mRNA transcripts were also detected in granulocytes, B cells, and T cells. Finally, we show that boMincle binds to isolated bovine CD4+ T cells in a specific manner, indicating the potential to recognise endogenous ligands. This suggests that the receptor might also play a role in homeostasis in cattle.
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Affiliation(s)
- Angela Holder
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Jeannine Kolakowski
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Chloe Rosentreter
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Ellen Knuepfer
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | | | | | - Heather Harris
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Lotta Baumgaertel
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
| | - Amanda Gibson
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
- Department of Life Sciences, Aberystwyth University, Aberystwyth, Ceredigion, United Kingdom
| | - Dirk Werling
- Centre for Vaccinology and Regenerative Medicine, Department of Pathobiology and Population Sciences, Royal Veterinary College, North Mymms, United Kingdom
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Korkmaz FT, Traber KE. Innate immune responses in pneumonia. Pneumonia (Nathan) 2023; 15:4. [PMID: 36829255 PMCID: PMC9957695 DOI: 10.1186/s41479-023-00106-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Accepted: 01/05/2023] [Indexed: 02/26/2023] Open
Abstract
The lungs are an immunologically unique environment; they are exposed to innumerable pathogens and particulate matter daily. Appropriate clearance of pathogens and response to pollutants is required to prevent overwhelming infection, while preventing tissue damage and maintaining efficient gas exchange. Broadly, the innate immune system is the collection of immediate, intrinsic immune responses to pathogen or tissue injury. In this review, we will examine the innate immune responses of the lung, with a particular focus on their role in pneumonia. We will discuss the anatomic barriers and antimicrobial proteins of the lung, pathogen and injury recognition, and the role of leukocytes (macrophages, neutrophils, and innate lymphocytes) and lung stromal cells in innate immunity. Throughout the review, we will focus on new findings in innate immunity as well as features that are unique to the lung.
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Affiliation(s)
- Filiz T Korkmaz
- Department of Medicine, Division of Immunology & Infectious Disease, University of Massachusetts, Worcester, MA, USA
- Pulmonary Center, Boston University School of Medicine, Boston, MA, USA
| | - Katrina E Traber
- Pulmonary Center, Boston University School of Medicine, Boston, MA, USA.
- Department of Medicine, Boston University School of Medicine, Boston, MA, USA.
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Wang M, Zhang Z, Dong X, Zhu B. Targeting β-glucans, vital components of the Pneumocystis cell wall. Front Immunol 2023; 14:1094464. [PMID: 36845149 PMCID: PMC9947646 DOI: 10.3389/fimmu.2023.1094464] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 01/16/2023] [Indexed: 02/11/2023] Open
Abstract
β-glucan is the most abundant polysaccharide in the cell wall of Pneumocystis jirovecii, which has attracted extensive attention because of its unique immunobiological characteristics. β-glucan binds to various cell surface receptors, which produces an inflammatory response and accounts for its immune effects. A deeper comprehension of the processes by Pneumocystis β-glucan recognizes its receptors, activates related signaling pathways, and regulates immunity as required. Such understanding will provide a basis for developing new therapies against Pneumocystis. Herein, we briefly review the structural composition of β-glucans as a vital component of the Pneumocystis cell wall, the host immunity mediated by β-glucans after their recognition, and discuss opportunities for the development of new strategies to combat Pneumocystis.
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Affiliation(s)
- Mengyan Wang
- Department II of Infectious Diseases, Xixi Hospital of Hangzhou, Hangzhou, China,Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhongdong Zhang
- Department II of Infectious Diseases, Xixi Hospital of Hangzhou, Hangzhou, China
| | - Xiaotian Dong
- Department of Clinical Laboratory, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Biao Zhu
- Department of Infectious Diseases, State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang, China,*Correspondence: Biao Zhu,
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Research progress on Mincle as a multifunctional receptor. Int Immunopharmacol 2023; 114:109467. [PMID: 36436471 DOI: 10.1016/j.intimp.2022.109467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/25/2022] [Accepted: 11/13/2022] [Indexed: 11/25/2022]
Abstract
Macrophage-induced C-type lectin (Mincle), a lipopolysaccharide-induced protein, is widely expressed on antigen-presenting cells. Mincle acts as a pattern recognition receptor that recognizes pathogen-associated molecular patterns of pathogens such as bacteria and fungi, mainly glycolipids, which induces an acquired immune response against microbial infection. Interestingly, Mincle can also identify patterns of lipid damage-associated molecule patterns released by injured cells, such as Sin3-associated protein 130 and β-glucosylceramides, which induces sterile inflammation and ultimately accelerates the progression of stroke, obesity, hepatitis, kidney injury, autoimmune diseases and tumors by promoting tissue inflammation. This article will review the various functions of Mincle, such as mediating sterile inflammation of tissues to accelerate disease progression, initiating immune responses to fight infection and promoting tumor progression.
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Tobola F, Wiltschi B. One, two, many: Strategies to alter the number of carbohydrate binding sites of lectins. Biotechnol Adv 2022; 60:108020. [PMID: 35868512 DOI: 10.1016/j.biotechadv.2022.108020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 06/23/2022] [Accepted: 07/15/2022] [Indexed: 11/29/2022]
Abstract
Carbohydrates are more than an energy-storage. They are ubiquitously found on cells and most proteins, where they encode biological information. Lectins bind these carbohydrates and are essential for translating the encoded information into biological functions and processes. Hundreds of lectins are known, and they are found in all domains of life. For half a century, researchers have been preparing variants of lectins in which the binding sites are varied. In this way, the traits of the lectins such as the affinity, avidity and specificity towards their ligands as well as their biological efficacy were changed. These efforts helped to unravel the biological importance of lectins and resulted in improved variants for biotechnological exploitation and potential medical applications. This review gives an overview on the methods for the preparation of artificial lectins and complexes thereof and how reducing or increasing the number of binding sites affects their function.
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Affiliation(s)
- Felix Tobola
- acib - Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria; Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria.
| | - Birgit Wiltschi
- acib - Austrian Centre of Industrial Biotechnology, Petersgasse 14, 8010 Graz, Austria; Institute of Molecular Biotechnology, Graz University of Technology, Petersgasse 14, 8010 Graz, Austria; Institute of Bioprocess Science and Engineering, Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Muthgasse 18, 1190 Vienna, Austria.
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Kottom TJ, Carmona EM, Limper AH. Gene Expression in Lung Epithelial Cells Following Interaction with Pneumocystis carinii and its Specific Life Forms Yields Insights into Host Gene Responses to Infection. Microbiol Immunol 2022; 66:238-251. [PMID: 35229348 PMCID: PMC9090966 DOI: 10.1111/1348-0421.12972] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 02/01/2022] [Accepted: 02/22/2022] [Indexed: 11/29/2022]
Abstract
Pneumocystis spp. interacts with epithelial cells in the alveolar spaces of the lung. It is thought that the binding of Pneumocystis to host cell epithelium is needed for life cycle completion and proliferation. The effect of this interaction on lung epithelial cells have previously shown that the trophic form of this organism greatly inhibits p34 cdc2 activity, a serine/threonine kinase required for transition from G2 to M phase in the cell cycle. To gain further insight into the host response during Pneumocystis pneumonia (PCP), we used microarray technology to profile epithelial cell (A549) gene expression patterns following Pneumocystis carinii interaction. Furthermore, we isolated separate populations of cyst and trophic forms of P. carinii, which were then applied to the lung epithelial cells. Differential expression of genes involved in various cellular functions dependent on the specific P. carinii life form in contact with the A549 cell were identified. The reliability of our data was further confirmed by Northern blot analysis on a number of selected up or down regulated transcripts. The transcriptional response to P. carinii was dominated by cytokines, apoptotic, and anti-apoptotic related genes. These results reveal several previously unknown effects of P. carinii on the lung epithelial cell and provide insight into the complex interactions of host and pathogen. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Theodore J Kottom
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, 55905, USA
| | - Eva M Carmona
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, 55905, USA
| | - Andrew H Limper
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, 55905, USA
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Fischer S, Stegmann F, Gnanapragassam VS, Lepenies B. From structure to function – Ligand recognition by myeloid C-type lectin receptors. Comput Struct Biotechnol J 2022; 20:5790-5812. [DOI: 10.1016/j.csbj.2022.10.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 10/14/2022] [Accepted: 10/14/2022] [Indexed: 11/29/2022] Open
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Kottom TJ, Carmona EM, Limper AH. Current State of Carbohydrate Recognition and C-Type Lectin Receptors in Pneumocystis Innate Immunity. Front Immunol 2021; 12:798214. [PMID: 34975910 PMCID: PMC8716372 DOI: 10.3389/fimmu.2021.798214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 11/30/2021] [Indexed: 11/13/2022] Open
Abstract
Pneumocystis jirovecii is one of the most common fungal pathogens in immunocompromised individuals. Pneumocystis jirovecii pneumonia (PJP) causes a significant host immune response that is driven greatly by the organism’s cell wall components including β-glucans and major surface glycoprotein (Msg). These ligands interact with a number of C-type lectin receptors (CLRs) leading to downstream activation of proinflammatory signaling pathways. This minireview provides a brief overview summarizing known CLR/Pneumocystis interactions.
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Affiliation(s)
- Theodore J. Kottom
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic, Rochester, MN, United States
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
- *Correspondence: Theodore J. Kottom,
| | - Eva M. Carmona
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic, Rochester, MN, United States
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
| | - Andrew H. Limper
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic, Rochester, MN, United States
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, United States
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Kottom TJ, Carmona EM, Schaefbauer K, Limper AH. Additional C-type lectin receptors mediate interactions with Pneumocystis organisms and major surface glycoprotein. J Med Microbiol 2021; 70:001470. [PMID: 34889727 PMCID: PMC8744274 DOI: 10.1099/jmm.0.001470] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Introduction. Pathogen-associated molecular patterns' (PAMPs) are microbial signatures that are recognized by host myeloid C-type lectin receptors (CLRs). These CLRs interact with micro-organisms via their carbohydrate recognition domains (CRDs) and engage signalling pathways within the cell resulting in pro-inflammatory and microbicidal responses.Gap statement. In this article, we extend our laboratory study of additional CLRs that recognize fungal ligands against Pneumocystis murina and Pneumocystis carinii and their purified major surface glycoproteins (Msgs).Aim. To study the potential of newly synthesized hFc-CLR fusions on binding to Pneumocystis and its Msg.Methods. A library of new synthesized hFc-CLR fusions was screened against Pneumocystis murina and Pneumocystis carinii organisms and their purified major surface glycoproteins (Msgs) found on the respective fungi via modified ELISA. Immunofluorescence assay (IFA) was implemented and quantified to verify results. mRNA expression analysis by quantitative PCR (q-PCR) was employed to detect respective CLRs found to bind fungal organisms in the ELISA and determine their expression levels in the mouse immunosuppressed Pneumocystis pneumonia (PCP) model.Results. We detected a number of the CLR hFc-fusions displayed significant binding with P. murina and P. carinii organisms, and similarly to their respective Msgs. Significant organism and Msg binding was observed for CLR members C-type lectin domain family 12 member A (CLEC12A), Langerin, macrophage galactose-type lectin-1 (MGL-1), and specific intracellular adhesion molecule-3 grabbing non-integrin homologue-related 3 (SIGNR3). Immunofluorescence assay (IFA) with the respective CLR hFc-fusions against whole P. murina life forms corroborated these findings. Lastly, we surveyed the mRNA expression profiles of the respective CLRs tested above in the mouse immunosuppressed Pneumocystis pneumonia (PCP) model and determined that macrophage galactose type C-type lectin (Mgl-1), implicated in recognizing terminal N-acetylgalactosamine (GalNAc) found in the glycoproteins of microbial pathogens was significantly up-regulated during infection.Conclusion. The data herein add to the growing list of CLRs recognizing Pneumocystis and provide insights for further study of organism/host immune cell interactions.
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Affiliation(s)
- Theodore J. Kottom
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, USA,*Correspondence: Theodore J. Kottom,
| | - Eva M. Carmona
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Kyle Schaefbauer
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Andrew H. Limper
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, USA
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10
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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] [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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Charpentier E, Ménard S, Marques C, Berry A, Iriart X. Immune Response in Pneumocystis Infections According to the Host Immune System Status. J Fungi (Basel) 2021; 7:jof7080625. [PMID: 34436164 PMCID: PMC8399367 DOI: 10.3390/jof7080625] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/12/2022] Open
Abstract
The host immune response is critical in Pneumocystis pneumonia (PCP). Immunocompetent hosts can eliminate the fungus without symptoms, while immunodeficient hosts develop PCP with an unsuitable excessive inflammatory response leading to lung damage. From studies based on rodent models or clinical studies, this review aimed to better understand the pathophysiology of Pneumocystis infection by analysing the role of immune cells, mostly lymphocytes, according to the immune status of the infected host. Hence, this review first describes the immune physiological response in infected immunocompetent hosts that are able to eliminate the fungus. The objective of the second part is to identify the immune elements required for the control of the fungus, focusing on specific immune deficiencies. Finally, the third part concentrates on the effect of the different immune elements in immunocompromised subjects during PCP, to better understand which cells are detrimental, and which, on the contrary, are beneficial once the disease has started. This work highlights that the immune response associated with a favourable outcome of the infection may differ according to the immune status of the host. In the case of immunocompetency, a close communication between B cells and TCD4 within tertiary lymphocyte structures appears critical to activate M2 macrophages without much inflammation. Conversely, in the case of immunodeficiency, a pro-inflammatory response including Th1 CD4, cytotoxic CD8, NK cells, and IFNγ release seems beneficial for M1 macrophage activation, despite the impact of inflammation on lung tissue.
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Affiliation(s)
- Eléna Charpentier
- Department of Parasitology-Mycology, Toulouse University Hospital, 31059 Toulouse, France;
- Infinity, Inserm, CNRS, University of Toulouse III, 31024 Toulouse, France; (S.M.); (C.M.)
- Correspondence: (E.C.); (X.I.)
| | - Sandie Ménard
- Infinity, Inserm, CNRS, University of Toulouse III, 31024 Toulouse, France; (S.M.); (C.M.)
| | - Catherine Marques
- Infinity, Inserm, CNRS, University of Toulouse III, 31024 Toulouse, France; (S.M.); (C.M.)
| | - Antoine Berry
- Department of Parasitology-Mycology, Toulouse University Hospital, 31059 Toulouse, France;
- Infinity, Inserm, CNRS, University of Toulouse III, 31024 Toulouse, France; (S.M.); (C.M.)
| | - Xavier Iriart
- Department of Parasitology-Mycology, Toulouse University Hospital, 31059 Toulouse, France;
- Infinity, Inserm, CNRS, University of Toulouse III, 31024 Toulouse, France; (S.M.); (C.M.)
- Correspondence: (E.C.); (X.I.)
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Survey of the Transcription Factor Responses of Mouse Lung Alveolar Macrophages to Pneumocystis murina. Pathogens 2021; 10:pathogens10050569. [PMID: 34066663 PMCID: PMC8151842 DOI: 10.3390/pathogens10050569] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 05/03/2021] [Accepted: 05/07/2021] [Indexed: 11/16/2022] Open
Abstract
Pneumocystis jirovecii is a fungal pathogen that can cause life-threatening infections in individuals who are immunocompromised. Acquired via inhalation, upon entering the respiratory tract, the fungi first encounter innate immune cells such as alveolar macrophages (AMs). Relatively little is known about the AM cellular responses to the organism, and particularly transcription factor (TF) profiles leading to early host responses during infection. Utilizing the Mouse Transcription Factors RT2 Profiler™ PCR Array, we report an initial TF survey of these macrophage and Pneumocystis interactions. Expression levels of a panel of mouse TFs were compared between unstimulated and Pneumocystis murina-stimulated AMs. Interestingly, a number of TFs previously implicated in pathogen–host cell interactions were highly up- or downregulated, including hif1a and Pparg. qPCR experiments were further conducted to verify the results of these surveyed transcripts. Furthermore, with immunoblotting, we show that HIF-1A and PPAR-γ are indeed significantly upregulated and downregulated, respectively. Lastly, and importantly, we report that in the mouse model of Pneumocystis pneumonia (PCP), which mimics human Pneumocystis jirovecii pneumonia (PJP), qPCR analysis of Pneumocystis murina lungs also mimic the initial TF profile analysis, suggesting an importance for these TFs in immunocompromised hosts with Pneumocystis pneumonia. These data demonstrate the use of TF profiling in host AMs and Pneumocystis organism interactions that may lead to a better understanding of the specific inflammatory responses of the host to Pneumocystis pneumonia and may inform novel strategies for potential therapeutics.
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Nguyen T, Hosono Y, Shimizu T, Yamasaki S, Williams SJ. Candida albicans steryl 6- O-acyl-α-D-mannosides agonize signalling through Mincle. Chem Commun (Camb) 2020; 56:15060-15063. [PMID: 33196722 DOI: 10.1039/d0cc06263d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The C-type lectin receptor Mincle binds Candida albicans and has been implicated in its pathobiology, but the molecular effectors responsible have not been identified. We report the synthesis of cholesteryl and ergosteryl 6-O-acyl-α-d-mannosides, produced by C. albicans mycelium, and demonstrate their ability to signal through human and mouse Mincle.
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Affiliation(s)
- Tram Nguyen
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, 3010, Victoria, Australia.
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Targeting CARD9 with Small-Molecule Therapeutics Inhibits Innate Immune Signaling and Inflammatory Response to Pneumocystis carinii β-Glucans. Antimicrob Agents Chemother 2020; 64:AAC.01210-20. [PMID: 32839216 DOI: 10.1128/aac.01210-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 08/15/2020] [Indexed: 11/20/2022] Open
Abstract
Pneumocystis jirovecii, the opportunistic fungus that causes Pneumocystis pneumonia (PCP) in humans, is a significant contributor to morbidity and mortality in immunocompromised patients. Given the profound deleterious inflammatory effects of the major β-glucan cell wall carbohydrate constituents of Pneumocystis through Dectin-1 engagement and downstream caspase recruitment domain-containing protein 9 (CARD9) immune activation, we sought to determine whether the pharmacodynamic activity of the known CARD9 inhibitor BRD5529 might have a therapeutic effect on macrophage innate immune signaling and subsequent downstream anti-inflammatory activity. The small-molecule inhibitor BRD5529 was able to significantly reduce both phospho-p38 and phospho-pERK1 signaling and tumor necrosis factor alpha (TNF-α) release during stimulation of macrophages with Pneumocystis cell wall β-glucans.
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15
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Kottom TJ, Hebrink DM, Carmona EM, Limper AH. Pneumocystis carinii Major Surface Glycoprotein Dampens Macrophage Inflammatory Responses to Fungal β-Glucan. J Infect Dis 2020; 222:1213-1221. [PMID: 32363390 DOI: 10.1093/infdis/jiaa218] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 04/24/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Pneumocystis major surface glycoprotein (Msg) is a 120-kD surface protein complex on the organism with importance in adhesion and immune recognition. In this study, we show that Msg significantly impairs tumor necrosis factor (TNF)-α secretion by macrophages induced by Saccharomyces cerevisiae and Pneumocystis carinii (Pc) β-glucans. METHODS Major surface glycoprotein was shown to greatly reduce β-glucan-induced Dectin-1 immunoreceptor tyrosine-based activating motif (ITAM) phosphorylation. Major surface glycoprotein also down regulated Dectin-1 receptor messenger ribonucleic acid (mRNA) expression in the macrophages. It is interesting that Msg incubation with macrophages resulted in significant mRNA upregulation of both C-type lectin receptors (CLR) Mincle and MCL in Msg protein presence alone but to even greater amounts in the presence of Pc β-glucan. RESULTS The silencing of MCL and Mincle resulted in TNF-α secretions similar to that of macrophages treated with Pneumocystis β-glucan alone, which is suggestive of an inhibitory role for these 2 CLRs in Msg-suppressive effects on host cell immune response. CONCLUSIONS Taken together, these data indicate that the Pneumocystis Msg surface protein complex can act to suppress host macrophage inflammatory responses to the proinflammatory β -glucan components of the organisms.
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Affiliation(s)
- Theodore J Kottom
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Deanne M Hebrink
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Eva M Carmona
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Andrew H Limper
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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16
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Kottom TJ, Nandakumar V, Hebrink DM, Carmona EM, Limper AH. A critical role for CARD9 in pneumocystis pneumonia host defence. Cell Microbiol 2020; 22:e13235. [PMID: 32548948 DOI: 10.1111/cmi.13235] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/15/2020] [Accepted: 06/09/2020] [Indexed: 12/19/2022]
Abstract
Caspase recruitment domains-containing protein 9 (CARD9) is an adaptor molecule critical for key signalling pathways initiated through C-type lectin receptors (CLRs). Previous studies demonstrated that Pneumocystis organisms are recognised through a variety of CLRs. However, the role of the downstream CARD9 adaptor signalling protein in host defence against Pneumocystis infection remains to be elucidated. Herein, we analysed the role of CARD9 in host defence against Pneumocystis both in CD4-depleted CARD9-/- and immunocompetent hosts. Card9 gene-disrupted (CARD9-/- ) mice were more susceptible to Pneumocystis, as evidenced by reduced fungal clearance in infected lungs compared to wild-type (WT) infected mice. Our data suggests that this defect was due to impaired proinflammatory responses. Furthermore, CARD9-/- macrophages were severely compromised in their ability to differentiate and express M1 and M2 macrophage polarisation markers, to enhanced mRNA expression for Dectin-1 and Mincle, and most importantly, to kill Pneumocystis in vitro. Remarkably, compared to WT mice, and despite markedly increased organism burdens, CARD9-/- animals did not exhibit worsened survival during pneumocystis pneumonia (PCP), perhaps related to decreased lung injury due to altered influx of inflammatory cells and decreased levels of proinflammatory cytokines in response to the organism. Finally, although innate phase cytokines were impaired in the CARD9-/- animals during PCP, T-helper cell cytokines were normal in immunocompetent CARD9-/- animals infected with Pneumocystis. Taken together, our data demonstrate that CARD9 has a critical function in innate immune responses against Pneumocystis.
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Affiliation(s)
- Theodore J Kottom
- Department of Pulmonary and Critical Care Medicine, Division of Thoracic Diseases Research, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Vijayalakshmi Nandakumar
- Department of Pulmonary and Critical Care Medicine, Division of Thoracic Diseases Research, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Deanne M Hebrink
- Department of Pulmonary and Critical Care Medicine, Division of Thoracic Diseases Research, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Eva M Carmona
- Department of Pulmonary and Critical Care Medicine, Division of Thoracic Diseases Research, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Andrew H Limper
- Department of Pulmonary and Critical Care Medicine, Division of Thoracic Diseases Research, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Hoy Z, Wright TW, Elliott M, Malone J, Bhagwat S, Wang J, Gigliotti F. Combination Immunotherapy with Passive Antibody and Sulfasalazine Accelerates Fungal Clearance and Promotes the Resolution of Pneumocystis-Associated Immunopathogenesis. Infect Immun 2020; 88:e00640-19. [PMID: 31611280 PMCID: PMC6977122 DOI: 10.1128/iai.00640-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 10/10/2019] [Indexed: 12/31/2022] Open
Abstract
The pulmonary immune response protects healthy individuals against Pneumocystis pneumonia (PcP). However, the immune response also drives immunopathogenesis in patients who develop severe PcP, and it is generally accepted that optimal treatment requires combination strategies that promote fungal killing and also provide effective immunomodulation. The anti-inflammatory drug sulfasalazine programs macrophages for enhanced Pneumocystis phagocytosis and also suppresses PcP-related immunopathogenesis. Anti-Pneumocystis antibody opsonizes Pneumocystis organisms for greater phagocytosis and may also mask antigens that drive immunopathogenesis. Thus, we hypothesized that combining antibody and sulfasalazine would have the dual benefit of enhancing fungal clearance while dampening immunopathogenesis and allow the rescue of severe PcP. To model a clinically relevant treatment scenario in mice, therapeutic interventions were withheld until clear symptoms of pneumonia were evident. When administered individually, both passive antibody and sulfasalazine improved pulmonary function and enhanced Pneumocystis clearance to similar degrees. However, combination treatment with antibody and sulfasalazine produced a more rapid improvement, with recovery of body weight, a dramatic improvement in pulmonary function, reduced lung inflammation, and the rapid clearance of the Pneumocystis organisms. Accelerated fungal clearance in the combination treatment group was associated with a significant increase in macrophage phagocytosis of Pneumocystis Both passive antibody and sulfasalazine resulted in the suppression of Th1 cytokines and a marked increase in lung macrophages displaying an alternatively activated phenotype, which were enhanced by combination treatment. Our data support the concept that passive antibody and sulfasalazine could be an effective and specific adjunctive therapy for PcP, with the potential to accelerate fungal clearance while attenuating PcP-associated immunopathogenesis.
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Affiliation(s)
- Zachary Hoy
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
| | - Terry W Wright
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Michael Elliott
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
| | - Jane Malone
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
| | - Samir Bhagwat
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
| | - Jing Wang
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
| | - Francis Gigliotti
- Department of Pediatrics, Division of Infectious Diseases, University of Rochester Medical Center, Rochester, New York, USA
- Department of Microbiology and Immunology, University of Rochester Medical Center, Rochester, New York, USA
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18
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C-Type Lectin Receptors in Antifungal Immunity. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1204:1-30. [PMID: 32152941 DOI: 10.1007/978-981-15-1580-4_1] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Most fungal species are harmless to humans and some exist as commensals on mucocutaneous surfaces. Yet many fungi are opportunistic pathogens, causing life-threatening invasive infections when the immune system becomes compromised. The fungal cell wall contains conserved pathogen-associated molecular patterns (PAMPs), which allow the immune system to distinguish between self (endogenous molecular patterns) and foreign material. Sensing of invasive microbial pathogens is achieved through recognition of PAMPs by pattern recognition receptors (PRRs). One of the predominant fungal-sensing PRRs is the C-type lectin receptor (CLR) family. These receptors bind to structures present on the fungal cell wall, eliciting various innate immune responses as well as shaping adaptive immunity. In this chapter, we specifically focus on the four major human fungal pathogens, Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans and Pneumocystis jirovecii, reviewing our current understanding of the CLRs that are involved in their recognition and protection of the host.
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19
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Abstract
The respiratory tract is tasked with responding to a constant and vast influx of foreign agents. It acts as an important first line of defense in the innate immune system and as such plays a crucial role in preventing the entry of invading pathogens. While physical barriers like the mucociliary escalator exert their effects through the clearance of these pathogens, diverse and dynamic cellular mechanisms exist for the activation of the innate immune response through the recognition of pathogen-associated molecular patterns (PAMPs). These PAMPs are recognized by pattern recognition receptors (PRRs) that are expressed on a number of myeloid cells such as dendritic cells, macrophages, and neutrophils found in the respiratory tract. C-type lectin receptors (CLRs) are PRRs that play a pivotal role in the innate immune response and its regulation to a variety of respiratory pathogens such as viruses, bacteria, and fungi. This chapter will describe the function of both activating and inhibiting myeloid CLRs in the recognition of a number of important respiratory pathogens as well as the signaling events initiated by these receptors.
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20
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Höft MA, Hoving JC, Brown GD. Signaling C-Type Lectin Receptors in Antifungal Immunity. Curr Top Microbiol Immunol 2020; 429:63-101. [PMID: 32936383 DOI: 10.1007/82_2020_224] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
We are all exposed to fungal organisms daily, and although many of these organisms are not harmful, billions of people a year contract a fungal infection. Most of these infections are not fatal and can be cleared by the host immune response. However, due to an increase in high-risk populations, the global fungal burden has increased, with more than 1.5 million deaths per year caused by invasive fungal infections. The fungal cell wall is an important surface for interacting with the host immune system as it contains pathogen-associated molecular patterns (PAMPs) which are detected as being foreign by the host pattern recognition receptors (PRRs). C-type lectin receptors are a group of PRRs that play a central role in the protection against invasive fungal infections. Following the recognition of fungal PAMPs, CLRs trigger various innate and adaptive immune responses. In this chapter, we specifically focus on C-type lectin receptors capable of activating downstream signaling pathways, resulting in protective antifungal immune responses. The current roles that these signaling CLRs play in protection against four of the most prevalent fungal infections affecting humans are reviewed. These include Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans and Pneumocystis jirovecii.
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Affiliation(s)
- Maxine A Höft
- AFGrica Medical Mycology Research Unit, Institute of Infectious Disease and Molecular Medicine (IDM) at the University of Cape Town, Werner & Beit South Building, Anzio Road, Observatory, 7925, Cape Town, South Africa
| | - J Claire Hoving
- AFGrica Medical Mycology Research Unit, Institute of Infectious Disease and Molecular Medicine (IDM) at the University of Cape Town, Werner & Beit South Building, Anzio Road, Observatory, 7925, Cape Town, South Africa
| | - Gordon D Brown
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Geoffrey Pope Building, Stocker Road, EX4 4QD, Exeter, UK.
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21
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Miyake Y, Yamasaki S. Immune Recognition of Pathogen-Derived Glycolipids Through Mincle. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1204:31-56. [DOI: 10.1007/978-981-15-1580-4_2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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22
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Hatinguais R, Willment JA, Brown GD. PAMPs of the Fungal Cell Wall and Mammalian PRRs. Curr Top Microbiol Immunol 2020; 425:187-223. [PMID: 32180018 DOI: 10.1007/82_2020_201] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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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23
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T Cell Antifungal Immunity and the Role of C-Type Lectin Receptors. Trends Immunol 2019; 41:61-76. [PMID: 31813764 PMCID: PMC7427322 DOI: 10.1016/j.it.2019.11.007] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2019] [Revised: 10/28/2019] [Accepted: 11/11/2019] [Indexed: 02/06/2023]
Abstract
Fungi can cause disease in humans, from mucocutaneous to life-threatening systemic infections. Initiation of antifungal immunity involves fungal recognition by pattern recognition receptors such as C-type lectin receptors (CLRs). These germline-encoded receptors trigger a multitude of innate responses including phagocytosis, fungal killing, and antigen presentation which can also shape the development of adaptive immunity. Recently, studies have shed light on how CLRs directly or indirectly modulate lymphocyte function. Moreover, CLR-mediated recognition of commensal fungi maintains homeostasis and prevents invasion from opportunistic commensals. We present an overview of current knowledge of antifungal T cell immune responses, with emphasis on the role of C-type lectins, and discuss how these receptors modulate these responses at different levels. CLRs are essential pattern recognition receptors involved in fungal recognition and initiation of protective antifungal immunity. CLRs promote the differentiation of mammalian T helper cell subsets essential for the control of systemic (Th1) and mucosal (Th17) fungal infections. CLRs are involved in antigen presentation, the expression of co-stimulatory molecules, and cytokine secretion; therefore, they can regulate lymphocyte function and adaptive immune responses at different levels. Fungal morphological changes, such as the transition from yeast to hyphae in Candida albicans during tissue invasion, affects recognition by CLRs and impacts on adaptive immune responses. CLRs recognize the fungal component of the microbiome that can influence T cell responses during infection at intestinal and peripheral sites.
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24
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Kottom TJ, Hebrink DM, Monteiro JT, Lepenies B, Carmona EM, Wuethrich M, Santo Dias LD, Limper AH. Myeloid C-type lectin receptors that recognize fungal mannans interact with Pneumocystis organisms and major surface glycoprotein. J Med Microbiol 2019; 68:1649-1654. [PMID: 31609198 DOI: 10.1099/jmm.0.001062] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Myeloid C-type lectin receptors (CLRs) are innate immune recognition molecules that bind to microorganisms via their carbohydrate recognition domains. In this study, we utilized a library of CLRs that recognize fungal mannans. We used this library to screen against Pneumocystis carinii (Pc) homogenates or purified Pc major surface glycoprotein (Msg) present on Pneumocystis. The results demonstrated that all of the mammalian CLR hFc-fusions tested displayed significant interaction/binding with Pc organisms, and furthermore to isolated Msg. Highest Pc organism and Msg binding activities were with CLR members Mincle, Dectin-2, DC-SIGN and MCL. An immunofluorescence assay with the respective CLR hFc-fusions against whole Pc life forms corroborated these findings. Although some of these CLRs have been implicated previously as important for Pneumocystis pathogenesis (Dectin-1/Dectin-2/Mincle), this is the first analysis of head-to-head comparison of known fungal mannan binding CLR-hFc fusions with Pc. Lastly, heat treatment resulted in reducted CLR binding.
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Affiliation(s)
- Theodore J Kottom
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Deanne M Hebrink
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Joao T Monteiro
- Immunology Unit and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Germany, Hannover
| | - Bernd Lepenies
- Immunology Unit and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Germany, Hannover
| | - Eva M Carmona
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
| | - Marcel Wuethrich
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Lucas Dos Santo Dias
- Departments of Pediatrics, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
| | - Andrew H Limper
- Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, MN, 55905, USA
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25
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Lu X, Nagata M, Yamasaki S. Mincle: 20 years of a versatile sensor of insults. Int Immunol 2019; 30:233-239. [PMID: 29726997 DOI: 10.1093/intimm/dxy028] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 04/28/2018] [Indexed: 12/11/2022] Open
Abstract
Macrophage-inducible C-type lectin, better known as Mincle, is a member of the C-type lectin receptor family and is encoded by Clec4e. Mincle was an orphan receptor for a long time after having been discovered as a lipopolysaccharide-induced protein, yet later an adjuvant glycolipid in mycobacteria-trehalose dimycolate-was identified as a ligand. Ligands for Mincle were also found existing in bacteria, fungi and even mammals. When confronted with foreign elements, Mincle can recognize characteristic pathogen-associated molecular patterns, mostly glycolipids, from Mycobacterium tuberculosis and other pathogens, and thus induce immune responses against infection. To maintain self-homeostasis, Mincle can recognize lipid-based damage-associated molecular patterns, thereby monitoring the internal environment. The mechanism by which Mincle functions in the immune system is also becoming more clear along with the identification of its ligands. Being expressed widely on antigen-presenting cells, Mincle activation leads to the production of cytokines and chemokines, neutrophil infiltration and other inflammatory responses. Besides, Mincle can induce acquired immunity such as antigen-specific T-cell responses and antibody production as an adjuvant receptor. In this review, we will retrospectively sketch the discovery and study of Mincle, and outline some current work on this receptor.
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Affiliation(s)
- Xiuyuan Lu
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Yamadaoka, Suita, Osaka, Japan.,Laboratory of Molecular Immunology, Immunology Frontier Research Center, Osaka University, Yamadaoka, Suita, Osaka, Japan.,Division of Molecular Immunology, Medical Institute of Bioregulation, Kyushu University, Maidashi, Higashi-ku, Fukuoka, Japan
| | - Masahiro Nagata
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Yamadaoka, Suita, Osaka, Japan
| | - Sho Yamasaki
- Department of Molecular Immunology, Research Institute for Microbial Diseases, Osaka University, Yamadaoka, Suita, Osaka, Japan.,Laboratory of Molecular Immunology, Immunology Frontier Research Center, Osaka University, Yamadaoka, Suita, Osaka, Japan.,Division of Molecular Immunology, Medical Institute of Bioregulation, Kyushu University, Maidashi, Higashi-ku, Fukuoka, Japan.,Division of Molecular Immunology, Medical Mycology Research Center, Chiba University, Inohana, Chuo-ku, Chiba, Japan
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26
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Li TH, Liu L, Hou YY, Shen SN, Wang TT. C-type lectin receptor-mediated immune recognition and response of the microbiota in the gut. Gastroenterol Rep (Oxf) 2019; 7:312-321. [PMID: 31687150 PMCID: PMC6821170 DOI: 10.1093/gastro/goz028] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 06/05/2019] [Accepted: 06/12/2019] [Indexed: 02/07/2023] Open
Abstract
C-type lectin receptors (CLRs) are powerful pattern-recognition receptors that discern ‘self’ and ‘non-self’ in our body and protect us from invasive pathogens by mediating immune recognition and response. The gastrointestinal tract is very important for the maintenance of homeostasis; it is the largest shelter for the billions of microorganisms in the body and CLRs play a crucial regulatory role in this system. This study focuses on several CLRs, including Dectin-1, Dectin-2, Dectin-3 and Mincle. We summarize the roles of CLRs in maintaining gastrointestinal immune-system homeostasis, especially their functions in mediating immune recognition and responses in the gut, discuss their relationships to some diseases, highlight the significance of CLR-mediated sensing of microbial and non-microbial compounds in the gut immune system and identify new therapeutic targets.
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Affiliation(s)
- Tian-Hang Li
- Immunology and Reproduction Biology Lab, Medical School of Nanjing University, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, P. R. China
| | - Ling Liu
- Immunology and Reproduction Biology Lab, Medical School of Nanjing University, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, P. R. China
| | - Ya-Yi Hou
- Immunology and Reproduction Biology Lab, Medical School of Nanjing University, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, P. R. China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu, P. R. China
| | - Su-Nan Shen
- Immunology and Reproduction Biology Lab, Medical School of Nanjing University, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, P. R. China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu, P. R. China
| | - Ting-Ting Wang
- Immunology and Reproduction Biology Lab, Medical School of Nanjing University, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, Jiangsu, P. R. China.,Jiangsu Key Laboratory of Molecular Medicine, Nanjing University, Nanjing, Jiangsu, P. R. China
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27
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van der Peet PL, Gunawan C, Watanabe M, Yamasaki S, Williams SJ. Synthetic β-1,2-Mannosyloxymannitol Glycolipid from the Fungus Malassezia pachydermatis Signals through Human Mincle. J Org Chem 2019; 84:6788-6797. [PMID: 31046282 DOI: 10.1021/acs.joc.9b00544] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Mincle is a C-type lectin receptor of the innate immune system with the ability to sense pathogens and commensals through lipidic metabolites. While a growing number of bacterial glycolipids have been discovered that can signal through human Mincle, no fungal metabolites are known that can signal through the human form of this receptor. We report the total synthesis of a complex β-1,2-mannosyloxymannitol glycolipid from Malassezia pachydermatis 44-2, which was reported to signal through the murine Mincle receptor. Assembly of 44-2 was achieved through a highly convergent route that exploits symmetry elements inherent within this molecule and delineation of conditions that maintain the delicate l-mannitol triester-triol array. We show that 44-2 is a potent agonist of human Mincle signaling and constitutes the first fungal metabolite identified that can signal through the human Mincle receptor, providing new insights into antifungal immunity.
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Affiliation(s)
- Phillip L van der Peet
- School of Chemistry and Bio21 Institute , University of Melbourne , Parkville , Australia 3010
| | - Christian Gunawan
- School of Chemistry and Bio21 Institute , University of Melbourne , Parkville , Australia 3010
| | | | | | - Spencer J Williams
- School of Chemistry and Bio21 Institute , University of Melbourne , Parkville , Australia 3010
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28
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Kottom TJ, Hebrink DM, Limper AH. Binding of Pneumocystis carinii to the lung epithelial cell receptor HSPA5 (GRP78). J Med Microbiol 2018; 67:1772-1777. [PMID: 30328808 DOI: 10.1099/jmm.0.000864] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The importance of lung macrophages in Pneumocystis-host interaction is well known, but little is known about the initial binding/colonization of the airway epithelium. Our prior studies have documented cell-signalling events that occur following binding of the organisms to lung epithelial cells; however, the receptors that mediate Pneumocystis attachment to lung surfaces have not yet been fully defined. Using affinity chromatography, we identified heat shock protein 5 (HSPA5), also known as GRP78, as a potential host receptor that may have relevance in Pneumocystis lung colonization. Pneumocystis carinii (Pc) organisms not only bound HSPA5 on a rat lung epithelial cell line, but also on primary rat airway epithelial cells (AECs). Furthermore, Pc bound CHO1 cells overexpressing HSPA5 more than the CHO1 parent line alone, supporting a role for Pc-HSPA5 protein interaction in mediating organism attachment. These results provide new insights into the interactions of Pneumocystis with host lung epithelium.
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Affiliation(s)
- Theodore J Kottom
- From the Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
| | - Deanne M Hebrink
- From the Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
| | - Andrew H Limper
- From the Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota 55905, USA
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29
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Goyal S, Castrillón-Betancur JC, Klaile E, Slevogt H. The Interaction of Human Pathogenic Fungi With C-Type Lectin Receptors. Front Immunol 2018; 9:1261. [PMID: 29915598 PMCID: PMC5994417 DOI: 10.3389/fimmu.2018.01261] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2018] [Accepted: 05/18/2018] [Indexed: 01/19/2023] Open
Abstract
Fungi, usually present as commensals, are a major cause of opportunistic infections in immunocompromised patients. Such infections, if not diagnosed or treated properly, can prove fatal. However, in most cases healthy individuals are able to avert the fungal attacks by mounting proper antifungal immune responses. Among the pattern recognition receptors (PRRs), C-type lectin receptors (CLRs) are the major players in antifungal immunity. CLRs can recognize carbohydrate ligands, such as β-glucans and mannans, which are mainly found on fungal cell surfaces. They induce proinflammatory immune reactions, including phagocytosis, oxidative burst, cytokine, and chemokine production from innate effector cells, as well as activation of adaptive immunity via Th17 responses. CLRs such as Dectin-1, Dectin-2, Mincle, mannose receptor (MR), and DC-SIGN can recognize many disease-causing fungi and also collaborate with each other as well as other PRRs in mounting a fungi-specific immune response. Mutations in these receptors affect the host response and have been linked to a higher risk in contracting fungal infections. This review focuses on how CLRs on various immune cells orchestrate the antifungal response and on the contribution of single nucleotide polymorphisms in these receptors toward the risk of developing such infections.
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Affiliation(s)
- Surabhi Goyal
- Institute for Microbiology and Hygiene, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Septomics Research Center, Jena University Hospital, Jena, Germany
| | - Juan Camilo Castrillón-Betancur
- Septomics Research Center, Jena University Hospital, Jena, Germany.,International Leibniz Research School for Microbial and Biomolecular Interactions, Leibniz Institute for Natural Product Research and Infection Biology/Hans Knöll Institute, Jena, Germany
| | - Esther Klaile
- Septomics Research Center, Jena University Hospital, Jena, Germany
| | - Hortense Slevogt
- Septomics Research Center, Jena University Hospital, Jena, Germany
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30
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Salazar F, Brown GD. Antifungal Innate Immunity: A Perspective from the Last 10 Years. J Innate Immun 2018; 10:373-397. [PMID: 29768268 DOI: 10.1159/000488539] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2018] [Accepted: 03/11/2018] [Indexed: 01/02/2023] Open
Abstract
Fungal pathogens can rarely cause diseases in immunocompetent individuals. However, commensal and normally nonpathogenic environmental fungi can cause life-threatening infections in immunocompromised individuals. Over the last few decades, there has been a huge increase in the incidence of invasive opportunistic fungal infections along with a worrying increase in antifungal drug resistance. As a consequence, research focused on understanding the molecular and cellular basis of antifungal immunity has expanded tremendously in the last few years. This review will provide an overview of the most exciting recent advances in innate antifungal immunity, discoveries that are helping to pave the way for the development of new strategies that are desperately needed to combat these devastating diseases.
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Flentje A, Kober KM, Carrico AW, Neilands TB, Flowers E, Heck NC, Aouizerat BE. Minority stress and leukocyte gene expression in sexual minority men living with treated HIV infection. Brain Behav Immun 2018; 70:335-345. [PMID: 29548994 PMCID: PMC5953835 DOI: 10.1016/j.bbi.2018.03.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/20/2018] [Accepted: 03/12/2018] [Indexed: 12/17/2022] Open
Abstract
Sexual minority (i.e., non-heterosexual) individuals experience poorer mental and physical health, accounted for in part by the additional burden of sexual minority stress occurring from being situated in a culture favoring heteronormativity. Informed by previous research, the purpose of this study was to identify the relationship between sexual minority stress and leukocyte gene expression related to inflammation, cancer, immune function, and cardiovascular function. Sexual minority men living with HIV who were on anti-retroviral medication, had viral load < 200 copies/mL, and had biologically confirmed, recent methamphetamine use completed minority stress measures and submitted blood samples for RNA sequencing on leukocytes. Differential gene expression and pathway analyses were conducted comparing those with clinically elevated minority stress (n = 18) and those who did not meet the clinical cutoff (n = 20), covarying reactive urine toxicology results for very recent stimulant use. In total, 90 differentially expressed genes and 138 gene set pathways evidencing 2-directional perturbation were observed at false discovery rate (FDR) < 0.10. Of these, 41 of the differentially expressed genes and 35 of the 2-directionally perturbed pathways were identified as functionally related to hypothesized mechanisms of inflammation, cancer, immune function, and cardiovascular function. The neuroactive-ligand receptor pathway (implicated in cancer development) was identified using signaling pathway impact analysis. Our results suggest several potential biological pathways for future work investigating the relationship between sexual minority stress and health.
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Affiliation(s)
- Annesa Flentje
- Community Health Systems, School of Nursing, University of California, San Francisco, United States.
| | - Kord M Kober
- Department of Physiological Nursing, School of Nursing, University of California, San Francisco, United States; Institute for Computational Health Sciences, University of California, San Francisco, United States
| | | | - Torsten B Neilands
- Center for AIDS Prevention Studies, Department of Medicine, University of California, San Francisco, United States
| | - Elena Flowers
- Department of Physiological Nursing, School of Nursing, University of California, San Francisco, United States; Institute for Human Genetics, University of California, San Francisco, United States
| | - Nicholas C Heck
- Department of Psychology, Marquette University, United States
| | - Bradley E Aouizerat
- Bluestone Center for Clinical Research, College of Dentistry, New York University, United States
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Del Fresno C, Iborra S, Saz-Leal P, Martínez-López M, Sancho D. Flexible Signaling of Myeloid C-Type Lectin Receptors in Immunity and Inflammation. Front Immunol 2018; 9:804. [PMID: 29755458 PMCID: PMC5932189 DOI: 10.3389/fimmu.2018.00804] [Citation(s) in RCA: 72] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/03/2018] [Indexed: 12/19/2022] Open
Abstract
Myeloid C-type lectin receptors (CLRs) are important sensors of self and non-self that work in concert with other pattern recognition receptors (PRRs). CLRs have been previously classified based on their signaling motifs as activating or inhibitory receptors. However, specific features of the ligand binding process may result in distinct signaling through a single motif, resulting in the triggering of non-canonical pathways. In addition, CLR ligands are frequently exposed in complex structures that simultaneously bind different CLRs and other PRRs, which lead to integration of heterologous signaling among diverse receptors. Herein, we will review how sensing by myeloid CLRs and crosstalk with heterologous receptors is modulated by many factors affecting their signaling and resulting in differential outcomes for immunity and inflammation. Finding common features among those flexible responses initiated by diverse CLR-ligand partners will help to harness CLR function in immunity and inflammation.
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Affiliation(s)
- Carlos Del Fresno
- Immunobiology Laboratory, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - Salvador Iborra
- Immunobiology Laboratory, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain.,Department of Immunology, School of Medicine, Universidad Complutense de Madrid, 12 de Octubre Health Research Institute (imas12), Madrid, Spain
| | - Paula Saz-Leal
- Immunobiology Laboratory, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - María Martínez-López
- Immunobiology Laboratory, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
| | - David Sancho
- Immunobiology Laboratory, Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain
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Abstract
Over the last decade, invasive fungal infections have emerged as a growing threat to human health worldwide and novel treatment strategies are urgently needed. In this context, investigations into host-pathogen interactions represent an important and promising field of research. Antigen presenting cells such as macrophages and dendritic cells are strategically located at the frontline of defence against potential invaders. Importantly, these cells express germline encoded pattern recognition receptors (PRRs), which sense conserved entities from pathogens and orchestrate innate immune responses. Herein, we review the latest findings regarding the biology and functions of the different classes of PRRs involved in pathogenic fungal recognition. We also discuss recent literature on PRR collaboration/crosstalk and the mechanisms involved in inhibiting/regulating PRR signalling. Finally, we discuss how the accumulated knowledge on PRR biology, especially Dectin-1, has been used for the design of new immunotherapies against fungal infections.
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Affiliation(s)
- Emmanuel C Patin
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, Wales, United Kingdom
| | - Aiysha Thompson
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, Wales, United Kingdom
| | - Selinda J Orr
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff CF14 4XN, Wales, United Kingdom.
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Kottom TJ, Hebrink DM, Jenson PE, Marsolek PL, Wüthrich M, Wang H, Klein B, Yamasaki S, Limper AH. Dectin-2 Is a C-Type Lectin Receptor that Recognizes Pneumocystis and Participates in Innate Immune Responses. Am J Respir Cell Mol Biol 2018; 58:232-240. [PMID: 28886250 DOI: 10.1165/rcmb.2016-0335oc] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Pneumocystis is an important fungal pathogen that causes life-threatening pneumonia in patients with AIDS and malignancy. Lung fungal pathogens are recognized by C-type lectin receptors (CLRs), which bind specific ligands and stimulate innate immune responses. The CLR Dectin-1 was previously shown to mediate immune responses to Pneumocystis spp. For this reason, we investigated a potential role for Dectin-2. Rats with Pneumocystis pneumonia (PCP) exhibited elevated Dectin-2 mRNA levels. Soluble Dectin-2 carbohydrate-recognition domain fusion protein showed binding to intact Pneumocystis carinii (Pc) and to native Pneumocystis major surface glycoprotein/glycoprotein A (Msg/gpA). RAW macrophage cells expressing V5-tagged Dectin-2 displayed enhanced binding to Pc and increased protein tyrosine phosphorylation. Furthermore, the binding of Pc to Dectin-2 resulted in Fc receptor-γ-mediated intracellular signaling. Alveolar macrophages from Dectin-2-deficient mice (Dectin-2-/-) showed significant decreases in phospho-Syk activation after challenge with Pc cell wall components. Stimulation of Dectin-2-/- alveolar macrophages with Pc components showed significant decreases in the proinflammatory cytokines IL-6 and TNF-α. Finally, during infection with Pneumocystis murina, Dectin-2-/- mice displayed downregulated mRNA expression profiles of other CLRs implicated in fungal immunity. Although Dectin-2-/- alveolar macrophages had reduced proinflammatory cytokine release in vitro, Dectin-2-/- deficiency did not reduce the overall resistance of these mice in the PCP model, and organism burdens were statistically similar in the long-term immunocompromised and short-term immunocompetent PCP models. These results suggest that Dectin-2 participates in the initial innate immune signaling response to Pneumocystis, but its deficiency does not impair resistance to the organism.
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Affiliation(s)
- Theodore J Kottom
- 1 Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Deanne M Hebrink
- 1 Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Paige E Jenson
- 1 Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Paige L Marsolek
- 1 Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota
| | | | | | - Bruce Klein
- 2 Department of Pediatrics.,3 Department of Internal Medicine, and.,4 Department of Medical Microbiology and Immunology, University of Wisconsin Medical School, University of Wisconsin Hospital and Clinics, Madison, Wisconsin; and
| | - Sho Yamasaki
- 5 Division of Molecular Immunology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan
| | - Andrew H Limper
- 1 Thoracic Diseases Research Unit, Departments of Medicine and Biochemistry, Mayo Clinic College of Medicine, Rochester, Minnesota
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Affiliation(s)
- Jennifer Claire Hoving
- Institute of Infectious Disease and Molecular Medicine (IDM), Department of Pathology, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- * E-mail:
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Mayer S, Moeller R, Monteiro JT, Ellrott K, Josenhans C, Lepenies B. C-Type Lectin Receptor (CLR)-Fc Fusion Proteins As Tools to Screen for Novel CLR/Bacteria Interactions: An Exemplary Study on Preselected Campylobacter jejuni Isolates. Front Immunol 2018; 9:213. [PMID: 29487596 PMCID: PMC5816833 DOI: 10.3389/fimmu.2018.00213] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Accepted: 01/25/2018] [Indexed: 12/17/2022] Open
Abstract
C-type lectin receptors (CLRs) are carbohydrate-binding receptors that recognize their ligands often in a Ca2+-dependent manner. Upon ligand binding, myeloid CLRs in innate immunity trigger or inhibit a variety of signaling pathways, thus initiating or modulating effector functions such as cytokine production, phagocytosis, and antigen presentation. CLRs bind to various pathogens, including viruses, fungi, parasites, and bacteria. The bacterium Campylobacter jejuni (C. jejuni) is a very frequent Gram-negative zoonotic pathogen of humans, causing severe intestinal symptoms. Interestingly, C. jejuni expresses several glycosylated surface structures, for example, the capsular polysaccharide (CPS), lipooligosaccharide (LOS), and envelope proteins. This “Methods” paper describes applications of CLR–Fc fusion proteins to screen for yet unknown CLR/bacteria interactions using C. jejuni as an example. ELISA-based detection of CLR/bacteria interactions allows a first prescreening that is further confirmed by flow cytometry-based binding analysis and visualized using confocal microscopy. By applying these methods, we identified Dectin-1 as a novel CLR recognizing two selected C. jejuni isolates with different LOS and CPS genotypes. In conclusion, the here-described applications of CLR–Fc fusion proteins represent useful methods to screen for and identify novel CLR/bacteria interactions.
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Affiliation(s)
- Sabine Mayer
- Immunology Unit and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Hannover, Germany
| | - Rebecca Moeller
- Immunology Unit and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Hannover, Germany
| | - João T Monteiro
- Immunology Unit and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Hannover, Germany
| | - Kerstin Ellrott
- Medical School Hannover, Institute for Medical Microbiology, Hannover, Germany.,German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany
| | - Christine Josenhans
- Medical School Hannover, Institute for Medical Microbiology, Hannover, Germany.,German Center for Infection Research (DZIF), Partner Site Hannover-Braunschweig, Germany.,Max von Pettenkofer Institute, Ludwig Maximilian University Munich, Munich, Germany.,German Center for Infection Research (DZIF), Partner Site Munich, Germany
| | - Bernd Lepenies
- Immunology Unit and Research Center for Emerging Infections and Zoonoses, University of Veterinary Medicine, Hannover, Germany
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Sparber F, LeibundGut-Landmann S. Host Responses to Malassezia spp. in the Mammalian Skin. Front Immunol 2017; 8:1614. [PMID: 29213272 PMCID: PMC5702624 DOI: 10.3389/fimmu.2017.01614] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/08/2017] [Indexed: 12/11/2022] Open
Abstract
The skin of mammalian organisms is home for a myriad of microbes. Many of these commensals are thought to have beneficial effects on the host by critically contributing to immune homeostasis. Consequently, dysbiosis can have detrimental effects for the host that may manifest with inflammatory diseases at the barrier tissue. Besides bacteria, fungi make an important contribution to the microbiota and among these, the yeast Malassezia widely dominates in most areas of the skin in healthy individuals. There is accumulating evidence that Malassezia spp. are involved in a variety of skin disorders in humans ranging from non- or mildly inflammatory conditions such as dandruff and pityriasis versicolor to more severe inflammatory skin diseases like seborrheic eczema and atopic dermatitis. In addition, Malassezia is strongly linked to the development of dermatitis and otitis externa in dogs. However, the association of Malassezia spp. with such diseases remains poorly characterized. Until now, studies on the fungus–host interaction remain sparse and they are mostly limited to experiments with isolated host cells in vitro. They suggest a multifaceted crosstalk of Malassezia spp. with the skin by direct activation of the host via conserved pattern recognition receptors and indirectly via the release of fungus-derived metabolites that can modulate the function of hematopoietic and/or non-hematopoietic cells in the barrier tissue. In this review, we discuss our current understanding of the host response to Malassezia spp. in the mammalian skin.
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Affiliation(s)
- Florian Sparber
- Section of Immunology, Vetsuisse Faculty, University of Zürich, Zürich, Switzerland
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Te Velde AA. The C-Type Lectin Mincle: Clues for a Role in Crohn's Disease Adjuvant Reaction. Front Immunol 2017; 8:1304. [PMID: 29109721 PMCID: PMC5660320 DOI: 10.3389/fimmu.2017.01304] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Accepted: 09/27/2017] [Indexed: 12/17/2022] Open
Affiliation(s)
- Anje A Te Velde
- Tytgat Institute for Liver and Intestinal Research, Academic Medical Center, Amsterdam, Netherlands
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39
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Patin EC, Orr SJ, Schaible UE. Macrophage Inducible C-Type Lectin As a Multifunctional Player in Immunity. Front Immunol 2017; 8:861. [PMID: 28791019 PMCID: PMC5525440 DOI: 10.3389/fimmu.2017.00861] [Citation(s) in RCA: 60] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 07/07/2017] [Indexed: 01/08/2023] Open
Abstract
The macrophage-inducible C-type lectin (Mincle) is an innate immune receptor on myeloid cells sensing diverse entities including pathogens and damaged cells. Mincle was first described as a receptor for the mycobacterial cell wall glycolipid, trehalose-6,6′-dimycolate, or cord factor, and the mammalian necrotic cell-derived alarmin histone deacetylase complex unit Sin3-associated protein 130. Upon engagement by its ligands, Mincle induces secretion of innate cytokines and other immune mediators modulating inflammation and immunity. Since its discovery more than 25 years ago, the understanding of Mincle’s immune function has made significant advances in recent years. In addition to mediating immune responses to infectious agents, Mincle has been linked to promote tumor progression, autoimmunity, and sterile inflammation; however, further studies are required to completely unravel the complex role of Mincle in these distinct host responses. In this review, we discuss recent findings on Mincle’s biology with an emphasis on its diverse functions in immunity.
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Affiliation(s)
- Emmanuel C Patin
- Priority Area Infections, Department Cellular Microbiology, Forschungszentrum Borstel, and German Center for Infection Research, TTU-TB, Borstel, Germany.,Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Selinda Jane Orr
- Division of Infection and Immunity, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Ulrich E Schaible
- Priority Area Infections, Department Cellular Microbiology, Forschungszentrum Borstel, and German Center for Infection Research, TTU-TB, Borstel, Germany
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40
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Abstract
Pathogenic fungi cause a wide range of syndromes in immune-competent and immune-compromised individuals, with life-threatening disease primarily seen in humans with HIV/AIDS and in patients receiving immunosuppressive therapies for cancer, autoimmunity, and end-organ failure. The discovery that specific primary immune deficiencies manifest with fungal infections and the development of animal models of mucosal and invasive mycoses have facilitated insight into fungus-specific recognition, signaling, effector pathways, and adaptive immune responses. Progress in deciphering the molecular and cellular basis of immunity against fungi is guiding preclinical studies into vaccine and immune reconstitution strategies for vulnerable patient groups. Furthermore, recent work has begun to address the role of endogenous fungal communities in human health and disease. In this review, we summarize a contemporary understanding of protective immunity against fungi.
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Affiliation(s)
- Michail S Lionakis
- Fungal Pathogenesis Unit, Laboratory of Clinical Infectious Diseases, National Institute of Allergy and Infectious Diseases, NIH, Bethesda, Maryland, USA
| | - Iliyan D Iliev
- Jill Roberts Institute for Research in IBD, Department of Medicine, Weill Cornell Medical College, New York, New York, USA
| | - Tobias M Hohl
- Infectious Disease Service, Department of Medicine, and Immunology Program, Memorial Sloan Kettering Cancer Center, New York, New York, USA
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