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Ma Z, Ensley HE, Graves B, Kruppa MD, Rice PJ, Lowman DW, Williams DL. Synthesis of a unique mannose α-1-phosphate side chain moiety found in Candida auris cell wall mannan. Carbohydr Res 2024; 537:109059. [PMID: 38408423 PMCID: PMC10957239 DOI: 10.1016/j.carres.2024.109059] [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: 12/29/2023] [Revised: 02/12/2024] [Accepted: 02/13/2024] [Indexed: 02/28/2024]
Abstract
Candida auris is an emerging fungal pathogen that has become a world-wide public health threat. While there have been numerous studies into the nature, composition and structure of the cell wall of Candida albicans and other Candida species, much less is known about the C. auris cell wall. We have shown that C. auris cell wall mannan contains a unique phosphomannan structure which distinguishes C. auris mannan from the mannans found in other fungal species. Specifically, C. auris exhibits two unique acid-labile mannose α-1-phosphate (Manα1PO4) sidechains that are absent in other fungal mannans and fungal pathogens. This unique mannan structural feature presents an opportunity for the development of vaccines, therapeutics, diagnostic tools and/or research reagents that target C. auris. Herein, we describe the successful synthesis and structural characterization of a Manα1PO4-containing disaccharide moiety that mimics the phosphomannan found in C. auris. Additionally, we present evidence that the synthetic Manα1PO4 glycomimetic is specifically recognized and bound by cell surface pattern recognition receptors, i.e. rhDectin-2, rhMannose receptor and rhMincle, that are known to play important roles in the innate immune response to C. auris as well as other fungal pathogens. The synthesis of the Manα1PO4 glycomimetic may represent an important starting point in the development of vaccines, therapeutics, diagnostics and research reagents which target a number of C. auris clinical strains. In addition, these data provide new insights and understanding into the structural biology of this unique fungal pathogen.
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Affiliation(s)
- Zuchao Ma
- Departments of Surgery, East Tennessee State University, Johnson City, TN, USA; Drug Discovery and Synthesis Core, East Tennessee State University, Johnson City, TN, USA; Center for Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.
| | - Harry E Ensley
- Departments of Surgery, East Tennessee State University, Johnson City, TN, USA; Drug Discovery and Synthesis Core, East Tennessee State University, Johnson City, TN, USA; Center for Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Bridget Graves
- Departments of Surgery, East Tennessee State University, Johnson City, TN, USA; Center for Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Michael D Kruppa
- Biomedical Sciences, East Tennessee State University, Johnson City, TN, USA; Center for Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Peter J Rice
- Center for Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA; Department of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, USA
| | - Douglas W Lowman
- Departments of Surgery, East Tennessee State University, Johnson City, TN, USA; Drug Discovery and Synthesis Core, East Tennessee State University, Johnson City, TN, USA; Center for Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - David L Williams
- Departments of Surgery, East Tennessee State University, Johnson City, TN, USA; Drug Discovery and Synthesis Core, East Tennessee State University, Johnson City, TN, USA; Center for Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
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2
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Sah SK, Yadav A, Kruppa MD, Rustchenko E. Identification of 10 genes on Candida albicans chromosome 5 that control surface exposure of the immunogenic cell wall epitope β-glucan and cell wall remodeling in caspofungin-adapted mutants. Microbiol Spectr 2023; 11:e0329523. [PMID: 37966256 PMCID: PMC10714753 DOI: 10.1128/spectrum.03295-23] [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: 09/06/2023] [Accepted: 10/10/2023] [Indexed: 11/16/2023] Open
Abstract
IMPORTANCE Candida infections are often fatal in immuno-compromised individuals, resulting in many thousands of deaths per year. Caspofungin has proven to be an excellent anti-Candida drug and is now the frontline treatment for infections. However, as expected, the number of resistant cases is increasing; therefore, new treatment modalities are needed. We are determining metabolic pathways leading to decreased drug susceptibility in order to identify mechanisms facilitating evolution of clinical resistance. This study expands the understanding of genes that modulate drug susceptibility and reveals new targets for the development of novel antifungal drugs.
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Affiliation(s)
- Sudisht K. Sah
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York, USA
| | - Anshuman Yadav
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York, USA
| | - Michael D. Kruppa
- Department of Biomedical Sciences, Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, USA
| | - Elena Rustchenko
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, New York, USA
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3
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Borriello F, Poli V, Shrock E, Spreafico R, Liu X, Pishesha N, Carpenet C, Chou J, Di Gioia M, McGrath ME, Dillen CA, Barrett NA, Lacanfora L, Franco ME, Marongiu L, Iwakura Y, Pucci F, Kruppa MD, Ma Z, Lowman DW, Ensley HE, Nanishi E, Saito Y, O'Meara TR, Seo HS, Dhe-Paganon S, Dowling DJ, Frieman M, Elledge SJ, Levy O, Irvine DJ, Ploegh HL, Williams DL, Zanoni I. An adjuvant strategy enabled by modulation of the physical properties of microbial ligands expands antigen immunogenicity. Cell 2022; 185:614-629.e21. [PMID: 35148840 PMCID: PMC8857056 DOI: 10.1016/j.cell.2022.01.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [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: 01/07/2021] [Revised: 10/19/2021] [Accepted: 01/14/2022] [Indexed: 12/15/2022]
Abstract
Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.
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Affiliation(s)
- Francesco Borriello
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Division of Immunology, Boston, MA, USA; Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Valentina Poli
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Division of Immunology, Boston, MA, USA
| | - Ellen Shrock
- Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Division of Genetics, Brigham and Women's Hospital, Program in Virology, Boston, MA, USA
| | - Roberto Spreafico
- Institute for Quantitative and Computational Biosciences, University of California, Los Angeles, Los Angeles, CA, USA
| | - Xin Liu
- Harvard Medical School, Boston, MA, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Novalia Pishesha
- Harvard Medical School, Boston, MA, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Claire Carpenet
- Harvard Medical School, Boston, MA, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - Janet Chou
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Division of Immunology, Boston, MA, USA
| | - Marco Di Gioia
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Division of Immunology, Boston, MA, USA
| | - Marisa E McGrath
- University of Maryland School of Medicine, Department of Microbiology and Immunology, Baltimore, MD, USA
| | - Carly A Dillen
- University of Maryland School of Medicine, Department of Microbiology and Immunology, Baltimore, MD, USA
| | - Nora A Barrett
- Harvard Medical School, Boston, MA, USA; Brigham and Women's Hospital, Division of Allergy and Clinical Immunology, Boston, MA, USA
| | - Lucrezia Lacanfora
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Division of Immunology, Boston, MA, USA; Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Marcella E Franco
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Division of Immunology, Boston, MA, USA; Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Laura Marongiu
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Milan, Italy
| | - Yoichiro Iwakura
- Center for Animal Disease Models, Research Institute for Biomedical Sciences, Tokyo University of Science, Tokyo, Japan
| | - Ferdinando Pucci
- Department of Otolaryngology-Head and Neck Surgery, Department of Cell, Developmental & Cancer Biology, Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA
| | - Michael D Kruppa
- Department of Biomedical Sciences, Quillen College of Medicine, Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
| | - Zuchao Ma
- Department of Surgery, Quillen College of Medicine, Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
| | - Douglas W Lowman
- Department of Surgery, Quillen College of Medicine, Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
| | - Harry E Ensley
- Department of Surgery, Quillen College of Medicine, Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
| | - Etsuro Nanishi
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Precision Vaccines Program, Boston, MA, USA
| | - Yoshine Saito
- Boston Children's Hospital, Precision Vaccines Program, Boston, MA, USA
| | - Timothy R O'Meara
- Boston Children's Hospital, Precision Vaccines Program, Boston, MA, USA
| | - Hyuk-Soo Seo
- Harvard Medical School, Boston, MA, USA; Dana-Farber Cancer Institute, Department of Cancer Biology, Boston, MA, USA
| | - Sirano Dhe-Paganon
- Harvard Medical School, Boston, MA, USA; Dana-Farber Cancer Institute, Department of Cancer Biology, Boston, MA, USA
| | - David J Dowling
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Precision Vaccines Program, Boston, MA, USA
| | - Matthew Frieman
- University of Maryland School of Medicine, Department of Microbiology and Immunology, Baltimore, MD, USA
| | - Stephen J Elledge
- Harvard Medical School, Boston, MA, USA; Howard Hughes Medical Institute, Division of Genetics, Brigham and Women's Hospital, Program in Virology, Boston, MA, USA
| | - Ofer Levy
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Precision Vaccines Program, Boston, MA, USA; Broad Institute of MIT & Harvard, Cambridge, MA, USA
| | - Darrell J Irvine
- Massachusetts Institute of Technology, Department of Biological Engineering and Department of Materials Science and Engineering, Koch Institute for Integrative Cancer Research, Ragon Institute of MGH, MIT and Harvard, Cambridge, MA, USA; Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Hidde L Ploegh
- Harvard Medical School, Boston, MA, USA; Program in Cellular and Molecular Medicine, Boston Children's Hospital, Boston, MA, USA
| | - David L Williams
- Department of Biomedical Sciences, Quillen College of Medicine, Center of Excellence in Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
| | - Ivan Zanoni
- Harvard Medical School, Boston, MA, USA; Boston Children's Hospital, Division of Immunology, Boston, MA, USA; Boston Children's Hospital, Division of Gastroenterology, Boston, MA, USA.
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Kruppa MD, Lowman DW, Ensley HE, Ma Z, Graves B, Kintner J, Hall JV, Ozment TR, Williams DL. Isolation, Physicochemical Characterization, Labeling, and Biological Evaluation of Mannans and Glucans. Methods Mol Biol 2022; 2542:323-360. [PMID: 36008676 DOI: 10.1007/978-1-0716-2549-1_24] [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] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The cell wall contains mannans and glucans that are recognized by the host immune system. In this chapter, we will describe the methods to isolate mannans and glucans from the C. albicans cell wall. In addition, we describe how to determine purity, molecular size, and structure of the mannans and glucans. We also detail how to prepare the carbohydrates for in vitro, ex vivo, or in vivo use by describing endotoxin removal (depyrogenation), derivatization, and labeling and evaluation of bioactivity.
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Affiliation(s)
- Michael D Kruppa
- Department of Biomedical Sciences, Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.
| | - Douglas W Lowman
- Department of Surgery, Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Harry E Ensley
- Department of Surgery, Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Zuchao Ma
- Department of Surgery, Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Bridget Graves
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Jennifer Kintner
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Jennifer V Hall
- Department of Biomedical Sciences, Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Tammy R Ozment
- Department of Surgery, Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - David L Williams
- Department of Surgery, Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
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5
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Lowman DW, Sameer Al-Abdul-Wahid M, Ma Z, Kruppa MD, Rustchenko E, Williams DL. Glucan and glycogen exist as a covalently linked macromolecular complex in the cell wall of Candida albicans and other Candida species. ACTA ACUST UNITED AC 2021; 7:100061. [PMID: 34765834 PMCID: PMC8572957 DOI: 10.1016/j.tcsw.2021.100061] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [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: 04/01/2021] [Revised: 08/21/2021] [Accepted: 08/22/2021] [Indexed: 11/17/2022]
Abstract
The fungal cell wall serves as the interface between the organism and its environment. Complex carbohydrates are a major component of the Candida albicans cell wall, i.e., glucan, mannan and chitin. β-Glucan is a pathogen associated molecular pattern (PAMP) composed of β-(1 → 3,1 → 6)-linked glucopyranosyl repeat units. This PAMP plays a key role in fungal structural integrity and immune recognition. Glycogen is an α-(1 → 4,1 → 6)-linked glucan that is an intracellular energy storage carbohydrate. We observed that glycogen was co-extracted during the isolation of β-glucan from C. albicans SC5314. We hypothesized that glucan and glycogen may form a macromolecular species that links intracellular glycogen with cell wall β-(1 → 3,1 → 6)-glucan. To test this hypothesis, we examined glucan-glycogen extracts by multi-dimensional NMR to ascertain if glycogen and β-glucan were interconnected. 1H NMR analyses confirmed the presence of glycogen and β-glucan in the macromolecule. Diffusion Ordered SpectroscopY (DOSY) confirmed that the β-glucan and glycogen co-diffuse, which indicates a linkage between the two polymers. We determined that the linkage is not via peptides and/or small proteins. Our data indicate that glycogen is covalently linked to β-(1 → 3,1 → 6) glucan via the β -(1 → 6)-linked side chain. We also found that the glucan-glycogen complex was present in C. dublinensis, C. haemulonii and C. auris, but was not present in C. glabrata or C. albicans hyphal glucan. These data demonstrate that glucan and glycogen form a novel macromolecular complex in the cell wall of C. albicans and other Candida species. This new and unique structure expands our understanding of the cell wall in Candida species.
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Affiliation(s)
- Douglas W Lowman
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Center of Excellence in Inflammation, Infectious Disease and Immunity, PO Box 70442, East Tennessee State University, Johnson City, TN, USA
| | | | - Zuchao Ma
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Center of Excellence in Inflammation, Infectious Disease and Immunity, PO Box 70442, East Tennessee State University, Johnson City, TN, USA
| | - Michael D Kruppa
- Center of Excellence in Inflammation, Infectious Disease and Immunity, PO Box 70442, East Tennessee State University, Johnson City, TN, USA.,Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Elena Rustchenko
- Department of Biochemistry and Biophysics, University of Rochester Medical Center, Rochester, NY, USA
| | - David L Williams
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA.,Center of Excellence in Inflammation, Infectious Disease and Immunity, PO Box 70442, East Tennessee State University, Johnson City, TN, USA
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6
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Borriello F, Spreafico R, Poli V, Shrock E, Chou J, Barrett NA, Lacanfora L, Franco ME, Marongiu L, Iwakura Y, Pucci F, Kruppa MD, Ma Z, Lowman DW, Ensley HE, Nanishi E, Saito Y, O’Meara TR, Seo HS, McGrath ME, Logue J, Haupt RE, Dhe-Paganon S, Dowling DJ, Frieman M, Elledge SJ, Levy O, Irvine DJ, Williams DL, Zanoni I. An adjuvant strategy enabled by modulation of the physical properties of fungal mannans elicits pan-coronavirus reactive anti-SARS-CoV-2 Spike antibodies. The Journal of Immunology 2021. [DOI: 10.4049/jimmunol.206.supp.30.08] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Abstract
Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate long-lasting adaptive immunity. While it is known that PRRs detect unique chemical patterns associated with invading microorganism, if and how the physical properties of PRR ligands influence development of the immune response is largely overlooked. Through the study of fungal mannans we present data that put the physical form of PRR ligands at the center of the process that determines the outcome of the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both periphery and dLN. When combined with SARS-CoV-2 Spike, this formulation elicits neutralizing anti-SARS-CoV-2 antibodies that cross-react with pathogenic coronaviruses. Thus, the physical properties of fungal ligands can be harnessed for rational adjuvant design and vaccine development.
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7
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Bruno M, Kersten S, Bain JM, Jaeger M, Rosati D, Kruppa MD, Lowman DW, Rice PJ, Graves B, Ma Z, Jiao YN, Chowdhary A, Renieris G, van de Veerdonk FL, Kullberg BJ, Giamarellos-Bourboulis EJ, Hoischen A, Gow NAR, Brown AJP, Meis JF, Williams DL, Netea MG. Transcriptional and functional insights into the host immune response against the emerging fungal pathogen Candida auris. Nat Microbiol 2020; 5:1516-1531. [PMID: 32839538 DOI: 10.1038/s41564-020-0780-3] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 07/27/2020] [Indexed: 01/26/2023]
Abstract
Candida auris is among the most important emerging fungal pathogens, yet mechanistic insights into its immune recognition and control are lacking. Here, we integrate transcriptional and functional immune-cell profiling to uncover innate defence mechanisms against C. auris. C. auris induces a specific transcriptome in human mononuclear cells, a stronger cytokine response compared with Candida albicans, but a lower macrophage lysis capacity. C. auris-induced innate immune activation is mediated through the recognition of C-type lectin receptors, mainly elicited by structurally unique C. auris mannoproteins. In in vivo experimental models of disseminated candidiasis, C. auris was less virulent than C. albicans. Collectively, these results demonstrate that C. auris is a strong inducer of innate host defence, and identify possible targets for adjuvant immunotherapy.
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Affiliation(s)
- Mariolina Bruno
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Simone Kersten
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Judith M Bain
- Medical Research Council Centre for Medical Mycology, University of Aberdeen, Aberdeen, UK
| | - Martin Jaeger
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Diletta Rosati
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Michael D Kruppa
- Departments of Surgery, Biomedical Sciences and Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Douglas W Lowman
- Departments of Surgery, Biomedical Sciences and Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Peter J Rice
- Department of Clinical Pharmacy, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, USA
| | - Bridget Graves
- Departments of Surgery, Biomedical Sciences and Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Zuchao Ma
- Departments of Surgery, Biomedical Sciences and Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Yue Ning Jiao
- Departments of Surgery, Biomedical Sciences and Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Anuradha Chowdhary
- Department of Medical Mycology, Vallabhbhai Patel Chest Institute, University of Delhi, New Delhi, India
| | - George Renieris
- 4th Department of Internal Medicine, National and Kapodistrian University of Athens, Medical School, Athens, Greece
| | - Frank L van de Veerdonk
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.,Center of Expertise in Mycology, Radboud University Medical Center and Canisius Wilhelmina Hospital, Nijmegen, the Netherlands
| | - Bart-Jan Kullberg
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.,Center of Expertise in Mycology, Radboud University Medical Center and Canisius Wilhelmina Hospital, Nijmegen, the Netherlands
| | | | - Alexander Hoischen
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands.,Department of Human Genetics, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Neil A R Gow
- Medical Research Council Centre for Medical Mycology, University of Aberdeen, Aberdeen, UK.,MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Alistair J P Brown
- Medical Research Council Centre for Medical Mycology, University of Aberdeen, Aberdeen, UK.,MRC Centre for Medical Mycology, University of Exeter, Exeter, UK
| | - Jacques F Meis
- Center of Expertise in Mycology, Radboud University Medical Center and Canisius Wilhelmina Hospital, Nijmegen, the Netherlands.,Bioprocess Engineering and Biotechnology Graduate Program, Federal University of Paraná, Curitiba, Brazil.,Department of Medical Microbiology and Infectious Diseases, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands
| | - David L Williams
- Departments of Surgery, Biomedical Sciences and Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA
| | - Mihai G Netea
- Department of Internal Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands. .,Department for Genomics & Immunoregulation, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany.
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8
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Graus MS, Wester MJ, Lowman DW, Williams DL, Kruppa MD, Martinez CM, Young JM, Pappas HC, Lidke KA, Neumann AK. Mannan Molecular Substructures Control Nanoscale Glucan Exposure in Candida. Cell Rep 2020; 24:2432-2442.e5. [PMID: 30157435 DOI: 10.1016/j.celrep.2018.07.088] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [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: 11/14/2017] [Revised: 07/05/2018] [Accepted: 07/27/2018] [Indexed: 12/26/2022] Open
Abstract
Cell wall mannans of Candida albicans mask β-(1,3)-glucan from recognition by Dectin-1, contributing to innate immune evasion. Glucan exposures are predominantly single receptor-ligand interaction sites of nanoscale dimensions. Candida species vary in basal glucan exposure and molecular complexity of mannans. We used super-resolution fluorescence imaging and a series of protein mannosylation mutants in C. albicans and C. glabrata to investigate the role of specific N-mannan features in regulating the nanoscale geometry of glucan exposure. Decreasing acid labile mannan abundance and α-(1,6)-mannan backbone length correlated most strongly with increased density and nanoscopic size of glucan exposures in C. albicans and C. glabrata, respectively. Additionally, a C. albicans clinical isolate with high glucan exposure produced similarly perturbed N-mannan structures and elevated glucan exposure geometry. Thus, acid labile mannan structure influences the nanoscale features of glucan exposure, impacting the nature of the pathogenic surface that triggers immunoreceptor engagement, aggregation, and signaling.
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Affiliation(s)
- Matthew S Graus
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Michael J Wester
- Department of Mathematics and Statistics, University of New Mexico, Albuquerque, NM 87131, USA
| | - Douglas W Lowman
- Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37684, USA; AppRidge International, LLC, Telford, TN 37690, USA
| | - David L Williams
- Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37684, USA; Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37684, USA
| | - Michael D Kruppa
- Center of Excellence in Inflammation, Infectious Disease and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37684, USA; Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN 37684, USA
| | - Carmen M Martinez
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Jesse M Young
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Harry C Pappas
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131, USA
| | - Keith A Lidke
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131, USA
| | - Aaron K Neumann
- Department of Pathology, University of New Mexico, Albuquerque, NM 87131, USA.
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9
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Kruppa MD, Jacobs J, King-Hook K, Galloway K, Berry A, Kintner J, Whittimore JD, Fritz R, Schoborg RV, Hall JV. Binding of Elementary Bodies by the Opportunistic Fungal Pathogen Candida albicans or Soluble β-Glucan, Laminarin, Inhibits Chlamydia trachomatis Infectivity. Front Microbiol 2019; 9:3270. [PMID: 30692972 PMCID: PMC6339894 DOI: 10.3389/fmicb.2018.03270] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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: 09/28/2018] [Accepted: 12/17/2018] [Indexed: 01/10/2023] Open
Abstract
Microbial interactions represent an understudied facet of human health and disease. In this study, the interactions that occur between Chlamydia trachomatis and the opportunistic fungal pathogen, Candida albicans were investigated. Candida albicans is a common component of the oral and vaginal microbiota responsible for thrush and vaginal yeast infections. Normally, Candida exist in the body as yeast. However, disruptions to the microbiota create conditions that allow expanded growth of Candida, conversion to the hyphal form, and tissue invasion. Previous studies have shown that a myriad of outcomes can occur when Candida albicans interacts with pathogenic bacteria. To determine if C. trachomatis physically interacts with C. albicans, we incubated chlamydial elementary bodies (EB) in medium alone or with C. albicans yeast or hyphal forms for 1 h. Following incubation, the samples were formaldehyde-fixed and processed for immunofluorescence assays using anti-chlamydial MOMP or anti- chlamydial LPS antibodies. Replicate samples were replenished with culture medium and incubated at 35°C for 0–120 h prior to fixation for immunofluorescence analysis or collection for EB infectivity assays. Data from this study indicates that both C. trachomatis serovar E and C. muridarum EB bind to C. albicans yeast and hyphal forms. This interaction was not blocked by pre-incubation of EB with the Candida cell wall components, mannan or β-glucans, suggesting that EB interact with a Candida cell wall protein or other structure. Bound EB remained attached to C. albicans for a minimum of 5 days (120 h). Infectivity assays demonstrated that EB bound to C. albicans are infectious immediately following binding (0h). However, once bound to C. albicans, EB infectivity decreased at a faster rate than EB in medium alone. At 6h post binding, 40% of EB incubated in medium alone remained infectious compared to only 16% of EB bound to C. albicans. Likewise, pre-incubation of EB with laminarin, a soluble preparation of β-glucan, alone or in combination with other fungal cell wall components significantly decreases chlamydial infectivity in HeLa cells. These data indicate that interactions between EB and C. albicans inhibit chlamydial infectivity, possibly by physically blocking EB interactions with host cell receptors.
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Affiliation(s)
- Michael D Kruppa
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States.,Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Jeremy Jacobs
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Kelsey King-Hook
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Keleigh Galloway
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Amy Berry
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States.,Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Jennifer Kintner
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States.,Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Judy D Whittimore
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States.,Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Rolf Fritz
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States.,Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Robert V Schoborg
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States.,Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
| | - Jennifer V Hall
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States.,Center for Infectious Disease, Inflammation and Immunity, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, United States
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10
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Abstract
Over the last 40 yr, the majority of research on glucans has focused on β-(1→3)-glucans. Recent studies indicate that β-(1→6)-glucans may be even more potent immune modulators than β-(1→3)-glucans. Mechanisms by which β-(1→6)-glucans are recognized and modulate immunity are unknown. In this study, we examined the interaction of purified water-soluble β-(1→6)-glucans with macrophage cell lines and primary peritoneal macrophages and the cellular and molecular consequences of this interaction. Our results indicate the existence of a specific β-(1→6)-glucan receptor that internalizes the glucan ligand via a clathrin-dependent mechanism. We show that the known β-(1→3)-glucans receptors are not responsible for β-(1→6)-glucan recognition and interaction. The receptor-ligand uptake/interaction has an apparent dissociation constant (KD) of ∼ 4 µM, and was associated with phosphorylation of ERK and JNK but not IκB-α or p38. Our results indicate that macrophage interaction with β-(1→6)-glucans may lead to modulation of genes associated with anti-fungal immunity and recruitment/activation of neutrophils. In summary, we show that macrophages specifically bind and internalize β-(1→6)-glucans followed by activation of intracellular signaling and modulation of anti-fungal immune response-related gene regulation. Thus, we conclude that the interaction between innate immunity and β-(1→6)-glucans may play an important role in shaping the anti-fungal immune response.
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Affiliation(s)
- Ilka Noss
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA Department of Pediatric Pneumology, Allergology and Neonatology, Hannover Medical School, Hannover, Germany
| | - Tammy R Ozment
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA Center for Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
| | - Bridget M Graves
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA Center for Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
| | - Michael D Kruppa
- Center for Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
| | - Peter J Rice
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of Colorado, Aurora, CO, USA
| | - David L Williams
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, TN, USA Center for Inflammation, Infectious Disease and Immunity, East Tennessee State University, Johnson City, TN, USA
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11
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Lowman DW, Greene RR, Bearden DW, Kruppa MD, Pottier M, Monteiro MA, Soldatov DV, Ensley HE, Cheng SC, Netea MG, Williams DL. Novel structural features in Candida albicans hyphal glucan provide a basis for differential innate immune recognition of hyphae versus yeast. J Biol Chem 2013; 289:3432-43. [PMID: 24344127 DOI: 10.1074/jbc.m113.529131] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The innate immune system differentially recognizes Candida albicans yeast and hyphae. It is not clear how the innate immune system effectively discriminates between yeast and hyphal forms of C. albicans. Glucans are major components of the fungal cell wall and key fungal pathogen-associated molecular patterns. C. albicans yeast glucan has been characterized; however, little is known about glucan structure in C. albicans hyphae. Using an extraction procedure that minimizes degradation of the native structure, we extracted glucans from C. albicans hyphal cell walls. (1)H NMR data analysis revealed that, when compared with reference (1→3,1→6) β-linked glucans and C. albicans yeast glucan, hyphal glucan has a unique cyclical or "closed chain" structure that is not found in yeast glucan. GC/MS analyses showed a high abundance of 3- and 6-linked glucose units when compared with yeast β-glucan. In addition to the expected (1→3), (1→6), and 3,6 linkages, we also identified a 2,3 linkage that has not been reported previously in C. albicans. Hyphal glucan induced robust immune responses in human peripheral blood mononuclear cells and macrophages via a Dectin-1-dependent mechanism. In contrast, C. albicans yeast glucan was a much less potent stimulus. We also demonstrated the capacity of C. albicans hyphal glucan, but not yeast glucan, to induce IL-1β processing and secretion. This finding provides important evidence for understanding the immune discrimination between colonization and invasion at the mucosal level. When taken together, these data provide a structural basis for differential innate immune recognition of C. albicans yeast versus hyphae.
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12
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Fox SJ, Shelton BT, Kruppa MD. Characterization of genetic determinants that modulate Candida albicans filamentation in the presence of bacteria. PLoS One 2013; 8:e71939. [PMID: 23951271 PMCID: PMC3737206 DOI: 10.1371/journal.pone.0071939] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/10/2013] [Indexed: 11/19/2022] Open
Abstract
In the human body, fungi and bacteria share many niches where the close contact of these organisms maintains a balance among the microbial population. However, when this microbial balance is disrupted, as with antibiotic treatment, other bacteria or fungi can grow uninhibited. C. albicans is the most common opportunistic fungal pathogen affecting humans and can uniquely control its morphogenesis between yeast, pseudohyphal, and hyphal forms. Numerous studies have shown that C. albicans interactions with bacteria can impact its ability to undergo morphogenesis; however, the genetics that govern this morphological control via these bacterial interactions are still relatively unknown. To aid in the understanding of the cross-kingdom interactions of C. albicans with bacteria and the impact on morphology we utilized a haploinsufficiency based C. albicans mutant screen to test for the ability of C. albicans to produce hyphae in the presence of three bacterial species (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus). Of the 18,144 mutant strains tested, 295 mutants produced hyphae in the presence of all three bacterial species. The 295 mutants identified 132 points of insertion, which included identified/predicted genes, major repeat sequences, and a number of non-coding/unannotated transcripts. One gene, CDR4, displayed increased expression when co-cultured with S. aureus, but not E. coli or P. aeruginosa. Our data demonstrates the ability to use a large scale library screen to identify genes involved in Candida-bacterial interactions and provides the foundation for comprehending the genetic pathways relating to bacterial control of C. albicans morphogenesis.
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Affiliation(s)
- Sean J. Fox
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
| | - Bryce T. Shelton
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
| | - Michael D. Kruppa
- Department of Biomedical Sciences, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
- * E-mail:
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13
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Hall RA, Bates S, Lenardon MD, MacCallum DM, Wagener J, Lowman DW, Kruppa MD, Williams DL, Odds FC, Brown AJP, Gow NAR. The Mnn2 mannosyltransferase family modulates mannoprotein fibril length, immune recognition and virulence of Candida albicans. PLoS Pathog 2013; 9:e1003276. [PMID: 23633946 PMCID: PMC3636026 DOI: 10.1371/journal.ppat.1003276] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.0] [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: 09/24/2012] [Accepted: 02/06/2013] [Indexed: 11/19/2022] Open
Abstract
The fungal cell wall is the first point of interaction between an invading fungal pathogen and the host immune system. The outer layer of the cell wall is comprised of GPI anchored proteins, which are post-translationally modified by both N- and O-linked glycans. These glycans are important pathogen associated molecular patterns (PAMPs) recognised by the innate immune system. Glycan synthesis is mediated by a series of glycosyl transferases, located in the endoplasmic reticulum and Golgi apparatus. Mnn2 is responsible for the addition of the initial α1,2-mannose residue onto the α1,6-mannose backbone, forming the N-mannan outer chain branches. In Candida albicans, the MNN2 gene family is comprised of six members (MNN2, MNN21, MNN22, MNN23, MNN24 and MNN26). Using a series of single, double, triple, quintuple and sextuple mutants, we show, for the first time, that addition of α1,2-mannose is required for stabilisation of the α1,6-mannose backbone and hence regulates mannan fibril length. Sequential deletion of members of the MNN2 gene family resulted in the synthesis of lower molecular weight, less complex and more uniform N-glycans, with the sextuple mutant displaying only un-substituted α1,6-mannose. TEM images confirmed that the sextuple mutant was completely devoid of the outer mannan fibril layer, while deletion of two MNN2 orthologues resulted in short mannan fibrils. These changes in cell wall architecture correlated with decreased proinflammatory cytokine induction from monocytes and a decrease in fungal virulence in two animal models. Therefore, α1,2-mannose of N-mannan is important for both immune recognition and virulence of C. albicans.
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Affiliation(s)
- Rebecca A. Hall
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Steven Bates
- Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Megan D. Lenardon
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Donna M. MacCallum
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Jeanette Wagener
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Douglas W. Lowman
- Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
- AppRidge International, LLC, Telford, Tennessee, United States of America
| | - Michael D. Kruppa
- Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
| | - David L. Williams
- Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
| | - Frank C. Odds
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Alistair J. P. Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
| | - Neil A. R. Gow
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, United Kingdom
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14
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Lowman DW, West LJ, Bearden DW, Wempe MF, Power TD, Ensley HE, Haynes K, Williams DL, Kruppa MD. New insights into the structure of (1→3,1→6)-β-D-glucan side chains in the Candida glabrata cell wall. PLoS One 2011; 6:e27614. [PMID: 22096604 PMCID: PMC3214063 DOI: 10.1371/journal.pone.0027614] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [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: 09/29/2010] [Accepted: 10/20/2011] [Indexed: 11/25/2022] Open
Abstract
β-Glucan is a (1→3)-β-linked glucose polymer with (1→6)-β-linked side chains and a major component of fungal cell walls. β-Glucans provide structural integrity to the fungal cell wall. The nature of the (1-6)-β-linked side chain structure of fungal (1→3,1→6)-β-D-glucans has been very difficult to elucidate. Herein, we report the first detailed structural characterization of the (1→6)-β-linked side chains of Candida glabrata using high-field NMR. The (1→6)-β-linked side chains have an average length of 4 to 5 repeat units spaced every 21 repeat units along the (1→3)-linked polymer backbone. Computer modeling suggests that the side chains have a bent curve structure that allows for a flexible interconnection with parallel (1→3)-β-D-glucan polymers, and/or as a point of attachment for proteins. Based on these observations we propose new approaches to how (1→6)-β-linked side chains interconnect with neighboring glucan polymers in a manner that maximizes fungal cell wall strength, while also allowing for flexibility, or plasticity.
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Affiliation(s)
- Douglas W. Lowman
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
- AppRidge International, LLC, Jonesborough, Tennessee, United States of America
| | - Lara J. West
- Department of Medicine, Imperial College London, London, United Kingdom
| | - Daniel W. Bearden
- Hollings Marine Laboratory, Analytical Chemistry Division, National Institutes of Standards and Technology, Charleston, South Carolina, United States of America
| | - Michael F. Wempe
- School of Pharmacy, University of Colorado Health Sciences Center, Denver, Colorado, United States of America
| | - Trevor D. Power
- Department of Biochemistry and Molecular Biology, Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, Texas, United States of America
| | - Harry E. Ensley
- Department of Chemistry, Tulane University, New Orleans, Louisiana, United States of America
| | - Ken Haynes
- Department of Medicine, Imperial College London, London, United Kingdom
| | - David L. Williams
- Department of Surgery, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
| | - Michael D. Kruppa
- Department of Microbiology, Quillen College of Medicine, East Tennessee State University, Johnson City, Tennessee, United States of America
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15
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Kruppa MD, Lowman DW, Chen YH, Selander C, Scheynius A, Monteiro MA, Williams DL. Identification of (1-->6)-beta-D-glucan as the major carbohydrate component of the Malassezia sympodialis cell wall. Carbohydr Res 2009; 344:2474-9. [PMID: 19853245 DOI: 10.1016/j.carres.2009.09.029] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2009] [Revised: 09/24/2009] [Accepted: 09/28/2009] [Indexed: 02/06/2023]
Abstract
Members of the genus Malassezia are commensal fungi found on the skin of both human and domestic animals and are associated with skin diseases including dandruff/seborrheic dermatitis, pityriasis versicolor, and atopic eczema (AE) in humans. In this study we have characterized the cell-wall carbohydrates of Malassezia sympodialis, one of the species most frequently isolated from both AE patients and healthy individuals. Cells were grown in liquid Dixon media at 32 degrees C, harvested, and processed using a standard Fehling's precipitation methodology for the isolation of mannan and a standard base/acid extraction for (1-->3)-beta-D-glucans. Using these classic extraction methods we were unable to isolate precipitable mannan or insoluble (1-->3)-beta-D-glucan. However, acidification and addition of methanol to the remaining Fehling's-treated sample resulted in a very clean precipitate. This material was characterized by GPC-MALLS, 1D and 2D NMR, and GC-MS for monomer-type and linkage-type composition. We determined that trace amounts of both mannan and branched (1-->3, 1-->6)-beta-D-glucan were present in the recovered precipitate, but not linear (1-->3)-beta-D-glucan. Surprisingly, NMR analysis indicated that (1-->6)-beta-D-glucan was the major carbohydrate component isolated from M. sympodialis cell wall. GC-MS linkage analysis confirmed the (1-->6)-beta-D-glucan structure. Based on these studies we have determined that the M. sympodialis cell wall contains (1-->6)-beta-D-glucan as the major carbohydrate component along with trace amounts of mannan and (1-->3, 1-->6)-beta-d-glucan. In addition, these data indicate that modification of the classic mannan isolation methodology may be useful in the simultaneous isolation of both mannan and (1-->6)-beta-D-glucan from other fungi.
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Affiliation(s)
- Michael D Kruppa
- Department of Microbiology, East Tennessee State University, James H Quillen College of Medicine, Johnson City, TN 37614-1708, United States.
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