1
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Schaefer S, Vij R, Sprague JL, Austermeier S, Dinh H, Judzewitsch PR, Müller-Loennies S, Lopes Silva T, Seemann E, Qualmann B, Hertweck C, Scherlach K, Gutsmann T, Cain AK, Corrigan N, Gresnigt MS, Boyer C, Lenardon MD, Brunke S. A synthetic peptide mimic kills Candida albicans and synergistically prevents infection. Nat Commun 2024; 15:6818. [PMID: 39122699 PMCID: PMC11315985 DOI: 10.1038/s41467-024-50491-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 07/11/2024] [Indexed: 08/12/2024] Open
Abstract
More than two million people worldwide are affected by life-threatening, invasive fungal infections annually. Candida species are the most common cause of nosocomial, invasive fungal infections and are associated with mortality rates above 40%. Despite the increasing incidence of drug-resistance, the development of novel antifungal formulations has been limited. Here we investigate the antifungal mode of action and therapeutic potential of positively charged, synthetic peptide mimics to combat Candida albicans infections. Our data indicates that these synthetic polymers cause endoplasmic reticulum stress and affect protein glycosylation, a mode of action distinct from currently approved antifungal drugs. The most promising polymer composition damaged the mannan layer of the cell wall, with additional membrane-disrupting activity. The synergistic combination of the polymer with caspofungin prevented infection of human epithelial cells in vitro, improved fungal clearance by human macrophages, and significantly increased host survival in a Galleria mellonella model of systemic candidiasis. Additionally, prolonged exposure of C. albicans to the synergistic combination of polymer and caspofungin did not lead to the evolution of tolerant strains in vitro. Together, this work highlights the enormous potential of these synthetic peptide mimics to be used as novel antifungal formulations as well as adjunctive antifungal therapy.
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Affiliation(s)
- Sebastian Schaefer
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, Australia
- Australian Centre for NanoMedicine, UNSW, Sydney, NSW, Australia
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Raghav Vij
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Jakob L Sprague
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Sophie Austermeier
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Hue Dinh
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Peter R Judzewitsch
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, Australia
- Australian Centre for NanoMedicine, UNSW, Sydney, NSW, Australia
| | - Sven Müller-Loennies
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Taynara Lopes Silva
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Eric Seemann
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Britta Qualmann
- Institute of Biochemistry I, Jena University Hospital - Friedrich Schiller University Jena, Jena, Germany
| | - Christian Hertweck
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
- Faculty of Biological Sciences, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
| | - Kirstin Scherlach
- Department of Biomolecular Chemistry, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Thomas Gutsmann
- Division of Biophysics, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
- Centre for Structural Systems Biology (CSSB), Hamburg, Germany
| | - Amy K Cain
- ARC Centre of Excellence in Synthetic Biology, School of Natural Sciences, Macquarie University, North Ryde, NSW, Australia
| | - Nathaniel Corrigan
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, Australia
- Australian Centre for NanoMedicine, UNSW, Sydney, NSW, Australia
| | - Mark S Gresnigt
- Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany
| | - Cyrille Boyer
- School of Chemical Engineering, University of New South Wales (UNSW), Sydney, NSW, Australia.
- Australian Centre for NanoMedicine, UNSW, Sydney, NSW, Australia.
| | - Megan D Lenardon
- School of Biotechnology and Biomolecular Sciences, UNSW, Sydney, NSW, Australia.
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans Knoell Institute, Jena, Germany.
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2
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King WR, Singer J, Warman M, Wilson D, Hube B, Lager I, Patton-Vogt J. The glycerophosphocholine acyltransferase Gpc1 contributes to phosphatidylcholine biosynthesis, long-term viability, and embedded hyphal growth in Candida albicans. J Biol Chem 2024; 300:105543. [PMID: 38072057 PMCID: PMC10790099 DOI: 10.1016/j.jbc.2023.105543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/21/2023] Open
Abstract
Candida albicans is a commensal fungus, opportunistic pathogen, and the most common cause of fungal infection in humans. The biosynthesis of phosphatidylcholine (PC), a major eukaryotic glycerophospholipid, occurs through two primary pathways. In Saccharomyces cerevisiae and some plants, a third PC synthesis pathway, the PC deacylation/reacylation pathway (PC-DRP), has been characterized. PC-DRP begins with the acylation of the lipid turnover product, glycerophosphocholine (GPC), by the GPC acyltransferase, Gpc1, to form Lyso-PC. Lyso-PC is then acylated by lysolipid acyltransferase, Lpt1, to produce PC. Importantly, GPC, the substrate for Gpc1, is a ubiquitous metabolite available within the host. GPC is imported by C. albicans, and deletion of the major GPC transporter, Git3, leads to decreased virulence in a murine model. Here we report that GPC can be directly acylated in C. albicans by the protein product of orf19.988, a homolog of ScGpc1. Through lipidomic studies, we show loss of Gpc1 leads to a decrease in PC levels. This decrease occurs in the absence of exogenous GPC, indicating that the impact on PC levels may be greater in the human host where GPC is available. A gpc1Δ/Δ strain exhibits several sensitivities to antifungals that target lipid metabolism. Furthermore, loss of Gpc1 results in both a hyphal growth defect in embedded conditions and a decrease in long-term cell viability. These results demonstrate for the first time the importance of Gpc1 and this alternative PC biosynthesis route (PC-DRP) to the physiology of a pathogenic fungus.
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Affiliation(s)
- William R King
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Justin Singer
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Mitchell Warman
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA
| | - Duncan Wilson
- Department of Biosciences, University of Exeter, Exeter, England
| | - Bernard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Products and Infection Biology Hans Knöll Institute, Jena, Germany
| | - Ida Lager
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Jana Patton-Vogt
- Department of Biological Sciences, Duquesne University, Pittsburgh, Pennsylvania, USA.
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3
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Roselletti E, Pericolini E, Nore A, Takacs P, Kozma B, Sala A, De Seta F, Comar M, Usher J, Brown GD, Wilson D. Zinc prevents vaginal candidiasis by inhibiting expression of an inflammatory fungal protein. Sci Transl Med 2023; 15:eadi3363. [PMID: 38055800 PMCID: PMC7616067 DOI: 10.1126/scitranslmed.adi3363] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 11/15/2023] [Indexed: 12/08/2023]
Abstract
Candida causes an estimated half-billion cases of vulvovaginal candidiasis (VVC) every year. VVC is most commonly caused by Candida albicans, which, in this setting, triggers nonprotective neutrophil infiltration, aggressive local inflammation, and symptomatic disease. Despite its prevalence, little is known about the molecular mechanisms underpinning the immunopathology of this fungal infection. In this study, we describe the molecular determinant of VVC immunopathology and a potentially straightforward way to prevent disease. In response to zinc limitation, C. albicans releases a trace mineral binding molecule called Pra1 (pH-regulated antigen). Here, we show that the PRA1 gene is strongly up-regulated during vaginal infections and that its expression positively correlated with proinflammatory cytokine concentrations in women. Genetic deletion of PRA1 prevented vaginal inflammation in mice, and application of a zinc solution down-regulated expression of the gene and also blocked immunopathology. We also show that treatment of women suffering from recurrent VVC with a zinc gel prevented reinfections. We have therefore identified a key mediator of symptomatic VVC, giving us an opportunity to develop a range of preventative measures for combatting this disease.
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Affiliation(s)
- Elena Roselletti
- Medical Research Council Centre for Medical Mycology at The University of Exeter, University of Exeter, Geoffrey Pope Building Stocker Road, Exeter, UK, EX4 4QD
| | - Eva Pericolini
- Department of Surgical, Medical, Dental and Morphological Sciences with Interest in Transplant, Oncological and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy, 41125
| | - Alexandre Nore
- Medical Research Council Centre for Medical Mycology at The University of Exeter, University of Exeter, Geoffrey Pope Building Stocker Road, Exeter, UK, EX4 4QD
| | - Peter Takacs
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary, 4032
- Division of Female Pelvic Medicine and Reconstructive Surgery, Department of Obstetrics and Gynecology, Eastern Virginia Medical School, Norfolk, VA, USA, 23507
| | - Bence Kozma
- Department of Obstetrics and Gynecology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary, 4032
| | - Arianna Sala
- Department of Surgical, Medical, Dental and Morphological Sciences with Interest in Transplant, Oncological and Regenerative Medicine, University of Modena and Reggio Emilia, Modena, Italy, 41125
| | - Francesco De Seta
- Department of Medical Sciences, University of Trieste, Institute for Maternal and Child Health-IRCCS, Burlo Garofolo, Trieste, Italy, 34137
| | - Manola Comar
- Unit of Advanced Microbiology Diagnosis and Translational Research, Institute for Maternal and Child Health—IRCCS “Burlo Garofolo”, University of Trieste, Trieste, Italy, 34137
| | - Jane Usher
- Medical Research Council Centre for Medical Mycology at The University of Exeter, University of Exeter, Geoffrey Pope Building Stocker Road, Exeter, UK, EX4 4QD
| | - Gordon D Brown
- Medical Research Council Centre for Medical Mycology at The University of Exeter, University of Exeter, Geoffrey Pope Building Stocker Road, Exeter, UK, EX4 4QD
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology at The University of Exeter, University of Exeter, Geoffrey Pope Building Stocker Road, Exeter, UK, EX4 4QD
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4
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Loh JT, Lam KP. Fungal infections: Immune defense, immunotherapies and vaccines. Adv Drug Deliv Rev 2023; 196:114775. [PMID: 36924530 DOI: 10.1016/j.addr.2023.114775] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2023] [Revised: 03/05/2023] [Accepted: 03/07/2023] [Indexed: 03/17/2023]
Abstract
Invasive fungal infection is an under recognized and emerging global health threat. Recently, the World Health Organization (WHO) released the first ever list of health-threatening fungi to guide research and public health interventions to strengthen global response to fungi infections and antifungal resistance. Currently, antifungal drugs only demonstrate partial success in improving prognosis of infected patients, and this is compounded by the rapid evolution of drug resistance among fungi species. The increased prevalence of fungal infections in individuals with underlying immunological deficiencies reflects the importance of an intact host immune system in controlling mycoses, and further highlights immunomodulation as a potential new avenue for the treatment of disseminated fungal diseases. In this review, we will summarize how host innate immune cells sense invading fungi through their pattern recognition receptors, and subsequently initiate a series of effector mechanisms and adaptive immune responses to mediate fungal clearance. In addition, we will discuss emerging preclinical and clinical data on antifungal immunotherapies and fungal vaccines which can potentially expand our antifungal armamentarium in future.
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Affiliation(s)
- Jia Tong Loh
- Singapore Immunology Network, Agency for Science, Technology and Research, 8A Biomedical Grove, S138648, Republic of Singapore.
| | - Kong-Peng Lam
- Singapore Immunology Network, Agency for Science, Technology and Research, 8A Biomedical Grove, S138648, Republic of Singapore; Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, 5, Science Drive 2, S117545, Republic of Singapore; School of Biological Sciences, College of Science, Nanyang Technological University, 60, Nanyang Drive, S637551, Republic of Singapore.
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5
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Begum N, Lee S, Portlock TJ, Pellon A, Nasab SDS, Nielsen J, Uhlen M, Moyes DL, Shoaie S. Integrative functional analysis uncovers metabolic differences between Candida species. Commun Biol 2022; 5:1013. [PMID: 36163459 PMCID: PMC9512779 DOI: 10.1038/s42003-022-03955-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Accepted: 09/07/2022] [Indexed: 12/02/2022] Open
Abstract
Candida species are a dominant constituent of the human mycobiome and associated with the development of several diseases. Understanding the Candida species metabolism could provide key insights into their ability to cause pathogenesis. Here, we have developed the BioFung database, providing an efficient annotation of protein-encoding genes. Along, with BioFung, using carbohydrate-active enzyme (CAZymes) analysis, we have uncovered core and accessory features across Candida species demonstrating plasticity, adaption to the environment and acquired features. We show a greater importance of amino acid metabolism, as functional analysis revealed that all Candida species can employ amino acid metabolism. However, metabolomics revealed that only a specific cluster of species (AGAu species—C. albicans, C. glabrata and C. auris) utilised amino acid metabolism including arginine, cysteine, and methionine metabolism potentially improving their competitive fitness in pathogenesis. We further identified critical metabolic pathways in the AGAu cluster with biomarkers and anti-fungal target potential in the CAZyme profile, polyamine, choline and fatty acid biosynthesis pathways. This study, combining genomic analysis, and validation with gene expression and metabolomics, highlights the metabolic diversity with AGAu species that underlies their remarkable ability to dominate they mycobiome and cause disease. Metabolic differences between Candida species are uncovered using the BioFung database alongside genomic and metabolic analysis.
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Affiliation(s)
- Neelu Begum
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, SE1 9RT, London, UK
| | - Sunjae Lee
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, SE1 9RT, London, UK
| | - Theo John Portlock
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, SE-171 21, Sweden
| | - Aize Pellon
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, SE1 9RT, London, UK
| | - Shervin Dokht Sadeghi Nasab
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, SE1 9RT, London, UK
| | - Jens Nielsen
- Department of Biology and Biological Engineering, Kemivägen 10, Chalmers University of Technology, SE-412 96, Gothenburg, Sweden.,BioInnovation Institute, Ole Maaløes Vej 3, DK2200, Copenhagen N, Denmark
| | - Mathias Uhlen
- Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, SE-171 21, Sweden
| | - David L Moyes
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, SE1 9RT, London, UK.
| | - Saeed Shoaie
- Centre for Host-Microbiome Interactions, Faculty of Dentistry, Oral & Craniofacial Sciences, King's College London, SE1 9RT, London, UK. .,Science for Life Laboratory, KTH - Royal Institute of Technology, Stockholm, SE-171 21, Sweden.
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6
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Ruiz-Castilla FJ, Ruiz Pérez FS, Ramos-Moreno L, Ramos J. Candida albicans Potassium Transporters. Int J Mol Sci 2022; 23:ijms23094884. [PMID: 35563275 PMCID: PMC9105532 DOI: 10.3390/ijms23094884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 04/26/2022] [Accepted: 04/26/2022] [Indexed: 12/10/2022] Open
Abstract
Potassium is basic for life. All living organisms require high amounts of intracellular potassium, which fulfils multiple functions. To reach efficient potassium homeostasis, eukaryotic cells have developed a complex and tightly regulated system of transporters present both in the plasma membrane and in the membranes of internal organelles that allow correct intracellular potassium content and distribution. We review the information available on the pathogenic yeast Candida albicans. While some of the plasma membrane potassium transporters are relatively well known and experimental data about their nature, function or regulation have been published, in the case of most of the transporters present in intracellular membranes, their existence and even function have just been deduced because of their homology with those present in other yeasts, such as Saccharomyces cerevisiae. Finally, we analyse the possible links between pathogenicity and potassium homeostasis. We comment on the possibility of using some of these transporters as tentative targets in the search for new antifungal drugs.
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7
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Fischer J, Gresnigt MS, Werz O, Hube B, Garscha U. Candida albicans-induced leukotriene biosynthesis in neutrophils is restricted to the hyphal morphology. FASEB J 2021; 35:e21820. [PMID: 34569657 DOI: 10.1096/fj.202100516rr] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2021] [Revised: 07/09/2021] [Accepted: 07/12/2021] [Indexed: 12/31/2022]
Abstract
Neutrophils are the most abundant leukocytes in circulation playing a key role in acute inflammation during microbial infections. Phagocytosis, one of the crucial defence mechanisms of neutrophils against pathogens, is amplified by chemotactic leukotriene (LT)B4 , which is biosynthesized via 5-lipoxygenase (5-LOX). However, extensive liberation of LTB4 can be destructive by over-intensifying the inflammatory process. While enzymatic biosynthesis of LTB4 is well characterized, less is known about molecular mechanisms that activate 5-LOX and lead to LTB4 formation during host-pathogen interactions. Here, we investigated the ability of the common opportunistic fungal pathogen Candida albicans to induce LTB4 formation in neutrophils, and elucidated pathogen-mediated drivers and cellular processes that activate this pathway. We revealed that C. albicans-induced LTB4 biosynthesis requires both the morphological transition from yeast cells to hyphae and the expression of hyphae-associated genes, as exclusively viable hyphae or yeast-locked mutant cells expressing hyphae-associated genes stimulated 5-LOX by [Ca2+ ]i mobilization and p38 MAPK activation. LTB4 biosynthesis was orchestrated by synergistic activation of dectin-1 and Toll-like receptor 2, and corresponding signaling via SYK and MYD88, respectively. Conclusively, we report hyphae-specific induction of LTB4 biosynthesis in human neutrophils. This highlights an expanding role of neutrophils during inflammatory processes in the response to C. albicans infections.
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Affiliation(s)
- Jana Fischer
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Greifswald University, Greifswald, Germany.,Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich Schiller University Jena, Jena, Germany
| | - Mark S Gresnigt
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, Jena, Germany
| | - Oliver Werz
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich Schiller University Jena, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, Jena, Germany.,Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Ulrike Garscha
- Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Greifswald University, Greifswald, Germany.,Department of Pharmaceutical/Medicinal Chemistry, Institute of Pharmacy, Friedrich Schiller University Jena, Jena, Germany
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8
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d'Enfert C, Kaune AK, Alaban LR, Chakraborty S, Cole N, Delavy M, Kosmala D, Marsaux B, Fróis-Martins R, Morelli M, Rosati D, Valentine M, Xie Z, Emritloll Y, Warn PA, Bequet F, Bougnoux ME, Bornes S, Gresnigt MS, Hube B, Jacobsen ID, Legrand M, Leibundgut-Landmann S, Manichanh C, Munro CA, Netea MG, Queiroz K, Roget K, Thomas V, Thoral C, Van den Abbeele P, Walker AW, Brown AJP. The impact of the Fungus-Host-Microbiota interplay upon Candida albicans infections: current knowledge and new perspectives. FEMS Microbiol Rev 2021; 45:fuaa060. [PMID: 33232448 PMCID: PMC8100220 DOI: 10.1093/femsre/fuaa060] [Citation(s) in RCA: 137] [Impact Index Per Article: 45.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Accepted: 11/18/2020] [Indexed: 12/11/2022] Open
Abstract
Candida albicans is a major fungal pathogen of humans. It exists as a commensal in the oral cavity, gut or genital tract of most individuals, constrained by the local microbiota, epithelial barriers and immune defences. Their perturbation can lead to fungal outgrowth and the development of mucosal infections such as oropharyngeal or vulvovaginal candidiasis, and patients with compromised immunity are susceptible to life-threatening systemic infections. The importance of the interplay between fungus, host and microbiota in driving the transition from C. albicans commensalism to pathogenicity is widely appreciated. However, the complexity of these interactions, and the significant impact of fungal, host and microbiota variability upon disease severity and outcome, are less well understood. Therefore, we summarise the features of the fungus that promote infection, and how genetic variation between clinical isolates influences pathogenicity. We discuss antifungal immunity, how this differs between mucosae, and how individual variation influences a person's susceptibility to infection. Also, we describe factors that influence the composition of gut, oral and vaginal microbiotas, and how these affect fungal colonisation and antifungal immunity. We argue that a detailed understanding of these variables, which underlie fungal-host-microbiota interactions, will present opportunities for directed antifungal therapies that benefit vulnerable patients.
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Affiliation(s)
- Christophe d'Enfert
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC 2019 INRA, 25, rue du Docteur Roux, 75015 Paris, France
| | - Ann-Kristin Kaune
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Ashgrove Road West, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Leovigildo-Rey Alaban
- BIOASTER Microbiology Technology Institute, 40 avenue Tony Garnier, 69007 Lyon, France
- Université de Paris, Sorbonne Paris Cité, 25, rue du Docteur Roux, 75015 Paris, France
| | - Sayoni Chakraborty
- Microbial Immunology Research Group, Emmy Noether Junior Research Group Adaptive Pathogenicity Strategies, and the Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Beutenbergstraße 11a, 07745 Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Neugasse 25, 07743 Jena, Germany
| | - Nathaniel Cole
- Gut Microbiology Group, Rowett Institute, University of Aberdeen, Ashgrove Road West, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Margot Delavy
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC 2019 INRA, 25, rue du Docteur Roux, 75015 Paris, France
- Université de Paris, Sorbonne Paris Cité, 25, rue du Docteur Roux, 75015 Paris, France
| | - Daria Kosmala
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC 2019 INRA, 25, rue du Docteur Roux, 75015 Paris, France
- Université de Paris, Sorbonne Paris Cité, 25, rue du Docteur Roux, 75015 Paris, France
| | - Benoît Marsaux
- ProDigest BV, Technologiepark 94, B-9052 Gent, Belgium
- Center for Microbial Ecology and Technology (CMET), Department of Biotechnology, Faculty of Bioscience Engineering, Ghent University, Coupure Links, 9000 Ghent, Belgium
| | - Ricardo Fróis-Martins
- Immunology Section, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 266a, Zurich 8057, Switzerland
- Institute of Experimental Immunology, University of Zurich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Moran Morelli
- Mimetas, Biopartner Building 2, J.H. Oortweg 19, 2333 CH Leiden, The Netherlands
| | - Diletta Rosati
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Marisa Valentine
- Microbial Immunology Research Group, Emmy Noether Junior Research Group Adaptive Pathogenicity Strategies, and the Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Beutenbergstraße 11a, 07745 Jena, Germany
| | - Zixuan Xie
- Gut Microbiome Group, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119–129, 08035 Barcelona, Spain
| | - Yoan Emritloll
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC 2019 INRA, 25, rue du Docteur Roux, 75015 Paris, France
| | - Peter A Warn
- Magic Bullet Consulting, Biddlecombe House, Ugbrook, Chudleigh Devon, TQ130AD, UK
| | - Frédéric Bequet
- BIOASTER Microbiology Technology Institute, 40 avenue Tony Garnier, 69007 Lyon, France
| | - Marie-Elisabeth Bougnoux
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC 2019 INRA, 25, rue du Docteur Roux, 75015 Paris, France
| | - Stephanie Bornes
- Université Clermont Auvergne, INRAE, VetAgro Sup, UMRF0545, 20 Côte de Reyne, 15000 Aurillac, France
| | - Mark S Gresnigt
- Microbial Immunology Research Group, Emmy Noether Junior Research Group Adaptive Pathogenicity Strategies, and the Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Beutenbergstraße 11a, 07745 Jena, Germany
| | - Bernhard Hube
- Microbial Immunology Research Group, Emmy Noether Junior Research Group Adaptive Pathogenicity Strategies, and the Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Beutenbergstraße 11a, 07745 Jena, Germany
| | - Ilse D Jacobsen
- Microbial Immunology Research Group, Emmy Noether Junior Research Group Adaptive Pathogenicity Strategies, and the Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knöll Institute, Beutenbergstraße 11a, 07745 Jena, Germany
| | - Mélanie Legrand
- Unité Biologie et Pathogénicité Fongiques, Département de Mycologie, Institut Pasteur, USC 2019 INRA, 25, rue du Docteur Roux, 75015 Paris, France
| | - Salomé Leibundgut-Landmann
- Immunology Section, Vetsuisse Faculty, University of Zurich, Winterthurerstrasse 266a, Zurich 8057, Switzerland
- Institute of Experimental Immunology, University of Zurich, Winterthurerstrasse 190, Zürich 8057, Switzerland
| | - Chaysavanh Manichanh
- Gut Microbiome Group, Vall d'Hebron Institut de Recerca (VHIR), Vall d'Hebron Hospital Universitari, Vall d'Hebron Barcelona Hospital Campus, Passeig Vall d'Hebron 119–129, 08035 Barcelona, Spain
| | - Carol A Munro
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Ashgrove Road West, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Mihai G Netea
- Department of Internal Medicine and Radboud Center for Infectious Diseases, Radboud University Medical Center, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands
| | - Karla Queiroz
- Mimetas, Biopartner Building 2, J.H. Oortweg 19, 2333 CH Leiden, The Netherlands
| | - Karine Roget
- NEXBIOME Therapeutics, 22 allée Alan Turing, 63000 Clermont-Ferrand, France
| | - Vincent Thomas
- BIOASTER Microbiology Technology Institute, 40 avenue Tony Garnier, 69007 Lyon, France
| | - Claudia Thoral
- NEXBIOME Therapeutics, 22 allée Alan Turing, 63000 Clermont-Ferrand, France
| | | | - Alan W Walker
- Gut Microbiology Group, Rowett Institute, University of Aberdeen, Ashgrove Road West, Foresterhill, Aberdeen AB25 2ZD, UK
| | - Alistair J P Brown
- MRC Centre for Medical Mycology, Department of Biosciences, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK
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9
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Abstract
Opportunistic commensal and environmental fungi can cause superficial to systemic diseases in humans. But how did these pathogens adapt to infect us and how does host-pathogen co-evolution shape their virulence potential? During evolution toward pathogenicity, not only do microorganisms gain virulence genes, but they also tend to lose non-adaptive genes in the host niche. Additionally, virulence factors can become detrimental during infection when they trigger host recognition. The loss of non-adaptive genes as well as the loss of the virulence potential of genes by adaptations to the host has been investigated in pathogenic bacteria and phytopathogenic fungi, where they are known as antivirulence and avirulence genes, respectively. However, these concepts are nearly unknown in the field of pathogenic fungi of humans. We think that this unnecessarily limits our view of human-fungal interplay, and that much could be learned if we applied a similar framework to aspects of these interactions. In this review, we, therefore, define and adapt the concepts of antivirulence and avirulence genes for human pathogenic fungi. We provide examples for analogies to antivirulence genes of bacterial pathogens and to avirulence genes of phytopathogenic fungi. Introducing these terms to the field of pathogenic fungi of humans can help to better comprehend the emergence and evolution of fungal virulence and disease.
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Affiliation(s)
- Sofía Siscar-Lewin
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany.,Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
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10
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Costa ACBP, Back-Brito GN, Mayer FL, Hube B, Wilson D. Candida albicans Mrv8, is involved in epithelial damage and biofilm formation. FEMS Yeast Res 2020; 20:5862582. [PMID: 32584995 PMCID: PMC7343537 DOI: 10.1093/femsyr/foaa033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 06/24/2020] [Indexed: 12/25/2022] Open
Abstract
Candida albicans is the most common human fungal pathogen that can cause superficial and deep-seated infections in susceptible individuals. Despite its medical importance, the vast majority of C. albicans genes remain of unknown function. Here, we report a role for the lineage-specific gene, MRV8, in host pathogen interactions, mycelial microcolony maturation and biofilm formation. In silico analysis indicated that MRV8 encodes a four-pass transmembrane protein unique to the closely related pathogens C. albicans and Candida dubliniensis. Deletion of MRV8 did not affect C. albicans adherence to, or initial invasion into human oral epithelia, but inhibited mycelial development and strongly reduced epithelial damage. mrv8Δ/Δ cells exhibited a media-dependent defect in biofilm formation and mutant biofilm metabolic activity was enhanced by cyclosporin A. mrv8Δ/Δ biofilms were more tolerant to treatment with caspofungin, but not to fluconazole or amphotericin B. Co-stimulation with calcium chloride and calcofluor white rescued biofilm growth in the presence of caspofungin, and this rescue-effect was Mrv8-dependent. Together, our data demonstrate an important role for a lineage-specific gene (MRV8) in C. albicans biofilm formation, drug tolerance and host–pathogen interactions.
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Affiliation(s)
- Anna Carolina Borges Pereira Costa
- Department of Biosciences and Oral Diagnosis, São Paulo State University (Unesp), Institute of Science and Technology (ICT); São José dos Campos, Brazil.,Department of Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany.,Aberdeen Fungal Group, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Aberdeen, United Kingdom
| | - Graziella Nuernberg Back-Brito
- Department of Biosciences and Oral Diagnosis, São Paulo State University (Unesp), Institute of Science and Technology (ICT); São José dos Campos, Brazil
| | - François L Mayer
- Department of Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany.,Friedrich Schiller University, Jena, Germany
| | - Duncan Wilson
- Department of Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany.,Aberdeen Fungal Group, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Aberdeen, United Kingdom.,Medical Research Council Centre for Medical Mycology, School of Biosciences, University of Exeter, Stocker Rd, Exeter EX4 4QD, Exeter, United Kingdom
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11
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Candidalysin Is a Potent Trigger of Alarmin and Antimicrobial Peptide Release in Epithelial Cells. Cells 2020; 9:cells9030699. [PMID: 32178483 PMCID: PMC7140650 DOI: 10.3390/cells9030699] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/06/2020] [Accepted: 03/10/2020] [Indexed: 12/18/2022] Open
Abstract
Host released alarmins and antimicrobial peptides (AMPs) are highly effective as antifungal agents and inducers. Whilst some are expressed constitutively at mucosal tissues, the primary site of many infections, others are elicited in response to pathogens. In the context of Candida albicans, the fungal factors inducing the release of these innate immune molecules are poorly defined. Herein, we identify candidalysin as a potent trigger of several key alarmins and AMPs known to possess potent anti-Candida functions. We also find extracellular ATP to be an important activator of candidalysin-induced epithelial signalling responses, namely epidermal growth factor receptor (EGFR) and MAPK signalling, which mediate downstream innate immunity during oral epithelial infection. The data provide novel mechanistic insight into the induction of multiple key alarmins and AMPs, important for antifungal defences against C. albicans.
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12
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Candida albicans rvs161Δ and rvs167Δ Endocytosis Mutants Are Defective in Invasion into the Oral Cavity. mBio 2019; 10:mBio.02503-19. [PMID: 31719181 PMCID: PMC6851284 DOI: 10.1128/mbio.02503-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Oropharyngeal candidiasis (OPC) is a common fungal infection that is associated with severe morbidity. Another concern is that patients at risk for developing OPC often take long courses of antifungal drugs, which can lead to the emergence of drug-resistant C. albicans strains. We therefore identified nine mutants with defects in undergoing invasive hyphal growth in the oral cavity, increasing the number of genes known to be involved in OPC by more than 30%. The two strongest mutants, rvs161Δ and rvs167Δ, have defects in endocytosis. The rvsΔ mutants appear to have a specific defect in initiating invasive growth, as preinducing the cells to form hyphae prior to infection restored their ability to cause OPC. These results indicate that blocking endocytosis could have therapeutic value in preventing the initiation of OPC without leading to development of resistance against drugs currently used to treat fungal infections. Invasive growth in tissues by the human fungal pathogen Candida albicans is promoted by a switch from budding to hyphal morphogenesis that is stimulated by multiple environmental factors that can vary at different sites of infection. To identify genes that promote invasive growth in the oral cavity to cause oropharyngeal candidiasis (OPC), we first identified C. albicans mutants that failed to invade agar medium. Analysis of nine severely defective mutants in a mouse model of OPC revealed that the strongest defects were seen for the rvs161Δ and rvs167Δ mutants, which lack amphiphysin proteins needed for endocytosis. The rvsΔ mutants initially adhered to the tongue but failed to invade efficiently and were lost from the oral cavity. Previous studies indicated that rvsΔ mutants formed filamentous hyphae in the kidney albeit with morphological abnormalities, suggesting that the rvsΔ mutants were influenced by factors that vary at different sites of infection. Consistent with this, increasing concentrations of CO2, an inducer of hyphal growth that is more abundant in internal organs than air, partially rescued the invasive-growth defects of the rvsΔ mutants in vitro. Interestingly, preinduction of the rvsΔ mutants to form hyphae prior to introduction into the oral cavity restored their ability to cause OPC, identifying a key role for endocytosis in initiating invasive hyphal growth. These results highlight the influence of distinct environmental factors in promoting invasive hyphal growth in the oral cavity and indicate that blocking endocytosis could have therapeutic value in preventing the initiation of OPC.
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13
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Candidalysin activates innate epithelial immune responses via epidermal growth factor receptor. Nat Commun 2019; 10:2297. [PMID: 31127085 PMCID: PMC6534540 DOI: 10.1038/s41467-019-09915-2] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 04/09/2019] [Indexed: 02/07/2023] Open
Abstract
Candida albicans is a fungal pathobiont, able to cause epithelial cell damage and immune activation. These functions have been attributed to its secreted toxin, candidalysin, though the molecular mechanisms are poorly understood. Here, we identify epidermal growth factor receptor (EGFR) as a critical component of candidalysin-triggered immune responses. We find that both C. albicans and candidalysin activate human epithelial EGFR receptors and candidalysin-deficient fungal mutants poorly induce EGFR phosphorylation during murine oropharyngeal candidiasis. Furthermore, inhibition of EGFR impairs candidalysin-triggered MAPK signalling and release of neutrophil activating chemokines in vitro, and diminishes neutrophil recruitment, causing significant mortality in an EGFR-inhibited zebrafish swimbladder model of infection. Investigation into the mechanism of EGFR activation revealed the requirement of matrix metalloproteinases (MMPs), EGFR ligands and calcium. We thus identify a PAMP-independent mechanism of immune stimulation and highlight candidalysin and EGFR signalling components as potential targets for prophylactic and therapeutic intervention of mucosal candidiasis. Candida albicans is an opportunistic fungus primarily affecting immunocompromised patients. Here, the authors identify a novel mechanism of host immune stimulation and highlight candidalysin and EGFR signalling components as potential targets for prophylactic and therapeutic intervention of mucosal candidiasis.
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14
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CURVELO JOSÉA, MORAES DANIELCDE, ANJOS CAMILAADOS, PORTELA MARISTELAB, SOARES ROSANGELAM. Histatin 5 and human lactoferrin inhibit biofilm formation of a fluconazole resistant Candida albicans clinical isolate. ACTA ACUST UNITED AC 2019; 91:e20180045. [DOI: 10.1590/0001-3765201920180045] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 04/17/2018] [Indexed: 01/03/2023]
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15
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Donovan PD, Holland LM, Lombardi L, Coughlan AY, Higgins DG, Wolfe KH, Butler G. TPP riboswitch-dependent regulation of an ancient thiamin transporter in Candida. PLoS Genet 2018; 14:e1007429. [PMID: 29852014 PMCID: PMC5997356 DOI: 10.1371/journal.pgen.1007429] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 06/12/2018] [Accepted: 05/18/2018] [Indexed: 11/30/2022] Open
Abstract
Riboswitches are non-coding RNA molecules that regulate gene expression by binding to specific ligands. They are primarily found in bacteria. However, one riboswitch type, the thiamin pyrophosphate (TPP) riboswitch, has also been described in some plants, marine protists and fungi. We find that riboswitches are widespread in the budding yeasts (Saccharomycotina), and they are most common in homologs of DUR31, originally described as a spermidine transporter. We show that DUR31 (an ortholog of N. crassa gene NCU01977) encodes a thiamin transporter in Candida species. Using an RFP/riboswitch expression system, we show that the functional elements of the riboswitch are contained within the native intron of DUR31 from Candida parapsilosis, and that the riboswitch regulates splicing in a thiamin-dependent manner when RFP is constitutively expressed. The DUR31 gene has been lost from Saccharomyces, and may have been displaced by an alternative thiamin transporter. TPP riboswitches are also present in other putative transporters in yeasts and filamentous fungi. However, they are rare in thiamin biosynthesis genes THI4 and THI5 in the Saccharomycotina, and have been lost from all genes in the sequenced species in the family Saccharomycetaceae, including S. cerevisiae. Thiamin, or Vitamin B1, is an essential requirement in all living organisms because it is a co-factor for many enzymes in metabolism. Unlike animals, many yeasts can synthesize thiamin, or they can import it from the environment. Expression of thiamin biosynthesis genes and of thiamin transporters is strictly regulated in response to the presence of thiamin. In many filamentous fungi, expression of thiamin biosynthesis genes is regulated by TPP riboswitches, RNA regulatory elements that are located within messenger RNA. TPP riboswitches are rare in yeasts. However, we find that TPP riboswitches are conserved in an ancient thiamin transporter, found in filamentous fungi, yeasts and other related organisms. There appears to be a high turnover of thiamin transporters in fungi, and there has been a gradual loss of TPP riboswitches in yeasts.
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Affiliation(s)
- Paul D. Donovan
- School of Biomedical and Biomolecular Science and UCD Conway Institute of Biomolecular and Biomedical Research, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Linda M. Holland
- School of Biomedical and Biomolecular Science and UCD Conway Institute of Biomolecular and Biomedical Research, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Lisa Lombardi
- School of Biomedical and Biomolecular Science and UCD Conway Institute of Biomolecular and Biomedical Research, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
| | - Aisling Y. Coughlan
- School of Medicine and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Desmond G. Higgins
- School of Medicine and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Kenneth H. Wolfe
- School of Medicine and UCD Conway Institute of Biomolecular and Biomedical Research, University College Dublin, Belfield, Dublin 4, Ireland
| | - Geraldine Butler
- School of Biomedical and Biomolecular Science and UCD Conway Institute of Biomolecular and Biomedical Research, Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
- * E-mail:
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16
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Crawford AC, Lehtovirta-Morley LE, Alamir O, Niemiec MJ, Alawfi B, Alsarraf M, Skrahina V, Costa ACBP, Anderson A, Yellagunda S, Ballou ER, Hube B, Urban CF, Wilson D. Biphasic zinc compartmentalisation in a human fungal pathogen. PLoS Pathog 2018; 14:e1007013. [PMID: 29727465 PMCID: PMC5955600 DOI: 10.1371/journal.ppat.1007013] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 05/16/2018] [Accepted: 04/09/2018] [Indexed: 12/14/2022] Open
Abstract
Nutritional immunity describes the host-driven manipulation of essential micronutrients, including iron, zinc and manganese. To withstand nutritional immunity and proliferate within their hosts, pathogenic microbes must express efficient micronutrient uptake and homeostatic systems. Here we have elucidated the pathway of cellular zinc assimilation in the major human fungal pathogen Candida albicans. Bioinformatics analysis identified nine putative zinc transporters: four cytoplasmic-import Zip proteins (Zrt1, Zrt2, Zrt3 and orf19.5428) and five cytoplasmic-export ZnT proteins (orf19.1536/Zrc1, orf19.3874, orf19.3769, orf19.3132 and orf19.52). Only Zrt1 and Zrt2 are predicted to localise to the plasma membrane and here we demonstrate that Zrt2 is essential for C. albicans zinc uptake and growth at acidic pH. In contrast, ZRT1 expression was found to be highly pH-dependent and could support growth of the ZRT2-null strain at pH 7 and above. This regulatory paradigm is analogous to the distantly related pathogenic mould, Aspergillus fumigatus, suggesting that pH-adaptation of zinc transport may be conserved in fungi and we propose that environmental pH has shaped the evolution of zinc import systems in fungi. Deletion of C. albicans ZRT2 reduced kidney fungal burden in wild type, but not in mice lacking the zinc-chelating antimicrobial protein calprotectin. Inhibition of zrt2Δ growth by neutrophil extracellular traps was calprotectin-dependent. This suggests that, within the kidney, C. albicans growth is determined by pathogen-Zrt2 and host-calprotectin. As well as serving as an essential micronutrient, zinc can also be highly toxic and we show that C. albicans deals with this potential threat by rapidly compartmentalising zinc within vesicular stores called zincosomes. In order to understand mechanistically how this process occurs, we created deletion mutants of all five ZnT-type transporters in C. albicans. Here we show that, unlike in Saccharomyces cerevisiae, C. albicans Zrc1 mediates zinc tolerance via zincosomal zinc compartmentalisation. This novel transporter was also essential for virulence and liver colonisation in vivo. In summary, we show that zinc homeostasis in a major human fungal pathogen is a multi-stage process initiated by Zrt1/Zrt2-cellular import, followed by Zrc1-dependent intracellular compartmentalisation.
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Affiliation(s)
- Aaron C. Crawford
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Laura E. Lehtovirta-Morley
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Omran Alamir
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Maria J. Niemiec
- Department of Clinical Microbiology, Umeå Centre for Microbial Research and Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology–Hans Knoell Institute, Jena, Germany
- Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
| | - Bader Alawfi
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Mohammad Alsarraf
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Volha Skrahina
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology–Hans Knoell Institute, Jena, Germany
| | - Anna C. B. P. Costa
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Andrew Anderson
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Sujan Yellagunda
- Department of Clinical Microbiology, Umeå Centre for Microbial Research and Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
| | - Elizabeth R. Ballou
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- Institute of Microbiology and Infection, and School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Bernhard Hube
- Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology–Hans Knoell Institute, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Constantin F. Urban
- Department of Clinical Microbiology, Umeå Centre for Microbial Research and Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- * E-mail:
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17
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Kjellerup L, Winther AML, Wilson D, Fuglsang AT. Cyclic AMP Pathway Activation and Extracellular Zinc Induce Rapid Intracellular Zinc Mobilization in Candida albicans. Front Microbiol 2018; 9:502. [PMID: 29619016 PMCID: PMC5871664 DOI: 10.3389/fmicb.2018.00502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Accepted: 03/05/2018] [Indexed: 11/15/2022] Open
Abstract
Zinc is an essential micronutrient, required for a range of zinc-dependent enzymes and transcription factors. In mammalian cells, zinc serves as a second messenger molecule. However, a role for zinc in signaling has not yet been established in the fungal kingdom. Here, we used the intracellular zinc reporter, zinbo-5, which allowed visualization of zinc in the endoplasmic reticulum and other components of the internal membrane system in Candida albicans. We provide evidence for a link between cyclic AMP/PKA- and zinc-signaling in this major human fungal pathogen. Glucose stimulation, which triggers a cyclic AMP spike in this fungus resulted in rapid intracellular zinc mobilization and this “zinc flux” could be stimulated with phosphodiesterase inhibitors and blocked via inhibition of adenylate cyclase or PKA. A similar mobilization of intracellular zinc was generated by stimulation of cells with extracellular zinc and this effect could be reversed with the chelator EDTA. However, zinc-induced zinc flux was found to be cyclic AMP independent. In summary, we show that activation of the cyclic AMP/PKA pathway triggers intracellular zinc mobilization in a fungus. To our knowledge, this is the first described link between cyclic AMP signaling and zinc homeostasis in a human fungal pathogen.
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Affiliation(s)
- Lasse Kjellerup
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark.,Pcovery ApS, Copenhagen, Denmark
| | | | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology, University of Aberdeen, Aberdeen Fungal Group, Aberdeen, United Kingdom
| | - Anja T Fuglsang
- Department of Plant and Environmental Sciences, University of Copenhagen, Frederiksberg, Denmark
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18
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Richardson JP, Moyes DL, Ho J, Naglik JR. Candida innate immunity at the mucosa. Semin Cell Dev Biol 2018; 89:58-70. [PMID: 29501618 DOI: 10.1016/j.semcdb.2018.02.026] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 02/27/2018] [Indexed: 12/17/2022]
Abstract
The tremendous diversity in microbial species that colonise the mucosal surfaces of the human body is only now beginning to be fully appreciated. Distinguishing between the behaviour of commensal microbes and harmful pathogens that reside at mucosal sites in the body is a complex, and exquisitely fine-tuned process central to mucosal health. The fungal pathobiont Candida albicans is frequently isolated from mucosal surfaces with an asymptomatic carriage rate of approximately 60% in the human population. While normally a benign member of the microbiota, overgrowth of C. albicans often results in localised mucosal infection causing morbidity in otherwise healthy individuals, and invasive infection that often causes death in the absence of effective immune defence. C. albicans triggers numerous innate immune responses at mucosal surfaces, and detection of C. albicans hyphae in particular, stimulates the production of antimicrobial peptides, danger-associated molecular patterns and cytokines that function to reduce fungal burdens during infection. This review will summarise our current understanding of innate immune responses to C. albicans at mucosal surfaces.
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Affiliation(s)
| | - David L Moyes
- Centre for Host-Microbiome Interactions, Mucosal & Salivary Biology Division, Dental Institute, King's College London, UK.
| | - Jemima Ho
- Mucosal & Salivary Biology Division, Dental Institute, King's College London, UK.
| | - Julian R Naglik
- Mucosal & Salivary Biology Division, Dental Institute, King's College London, UK.
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19
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Schrevens S, Van Zeebroeck G, Riedelberger M, Tournu H, Kuchler K, Van Dijck P. Methionine is required for cAMP-PKA-mediated morphogenesis and virulence of Candida albicans. Mol Microbiol 2018; 108:258-275. [PMID: 29453849 DOI: 10.1111/mmi.13933] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/14/2018] [Indexed: 12/24/2022]
Abstract
Candida albicans is a major human fungal pathogen, causing superficial, as well as life-threatening invasive infections. Therefore, it has to adequately sense and respond to the host defense by expressing appropriate virulence attributes. The most important virulence factor of C. albicans is the yeast-to-hyphae morphogenetic switch, which can be induced by numerous environmental cues, including the amino acid methionine. Here, we show an essential role for methionine permease Mup1 in methionine-induced morphogenesis, biofilm formation, survival inside macrophages and virulence. Furthermore, we demonstrate that this process requires conversion of methionine into S-adenosyl methionine (SAM) and its decarboxylation by Spe2. The resulting amino-propyl group is then used for biosynthesis of polyamines, which have been shown to activate adenylate cyclase. Inhibition of the SPE2 SAM decarboxylase gene strongly impairs methionine-induced morphogenesis on specific media and significantly delays virulence in the mouse systemic infection model system. Further proof of the connection between methionine uptake and initial metabolism and the cAMP-PKA pathway was obtained by showing that both Mup1 and Spe2 are required for cAMP production in response to methionine. Our results suggest that amino acid transport and further metabolism are interesting therapeutic targets as inhibitors of this may prevent the morphogenetic switch, thereby preventing virulence.
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Affiliation(s)
- Sanne Schrevens
- VIB - KU Leuven Center for Microbiology, Leuven 3001, Belgium.,Laboratory of Molecular Cell Biology, KU Leuven, Leuven 3001, Belgium
| | - Griet Van Zeebroeck
- VIB - KU Leuven Center for Microbiology, Leuven 3001, Belgium.,Laboratory of Molecular Cell Biology, KU Leuven, Leuven 3001, Belgium
| | - Michael Riedelberger
- Medical University of Vienna, Center of Medical Biochemistry, Max F. Perutz Laboratories, Campus Vienna Biocenter, Vienna, Austria
| | - Hélène Tournu
- VIB - KU Leuven Center for Microbiology, Leuven 3001, Belgium.,Laboratory of Molecular Cell Biology, KU Leuven, Leuven 3001, Belgium
| | - Karl Kuchler
- Medical University of Vienna, Center of Medical Biochemistry, Max F. Perutz Laboratories, Campus Vienna Biocenter, Vienna, Austria
| | - Patrick Van Dijck
- VIB - KU Leuven Center for Microbiology, Leuven 3001, Belgium.,Laboratory of Molecular Cell Biology, KU Leuven, Leuven 3001, Belgium
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20
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Li SX, Song YJ, Zhang YS, Wu HT, Guo H, Zhu KJ, Li DM, Zhang H. Mitochondrial Complex V α Subunit Is Critical for Candida albicans Pathogenicity through Modulating Multiple Virulence Properties. Front Microbiol 2017; 8:285. [PMID: 28280492 PMCID: PMC5322696 DOI: 10.3389/fmicb.2017.00285] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 02/13/2017] [Indexed: 11/22/2022] Open
Abstract
The α subunit (ATP1) is a vital component of mitochondrial complex V which counts for the majority of cellular ATP production in a living organism. Nevertheless, how the α subunit influences other cellular processes such as pathogenicity in Candida albicans remains poorly understood. To address this question, ATP1 mutant (atp1Δ/Δ) and the gene-reconstituted strain (atp1Δ/ATP1) have been constructed in this study and their pathogenicity-related traits are compared to those of wild type (WT). In a murine model of disseminated candidiasis, atp1Δ/Δ infected mice have a significantly higher survival rate and experience a lower fungal burden in tissues. In in vitro studies atp1Δ/Δ lose a capability to damage or destroy macrophages and endothelial cells. Furthermore, atp1Δ/Δ is not able to grow under either glucose-denial conditions or high H2O2 conditions, both of which are associated with the potency of the macrophages to kill C. albicans. Defects in filamentation and biofilm formation may impair the ability of atp1Δ/Δ to penetrate host cells and establish robust colonies in the host tissues. In concert with these pathogenic features, intracellular ATP levels of atp1Δ/Δ can drop to 1/3 of WT level. These results indicate that the α subunit of Complex V play important roles in C. albicans pathogenicity.
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Affiliation(s)
- Shui-Xiu Li
- The First Affiliated Hospital of Jinan UniversityGuangzhou, China; Institute of Mycology, Jinan UniversityGuangzhou, China
| | - Yan-Jun Song
- The First Affiliated Hospital of Jinan UniversityGuangzhou, China; Institute of Mycology, Jinan UniversityGuangzhou, China
| | - Yi-Shan Zhang
- The First Affiliated Hospital of Jinan UniversityGuangzhou, China; Institute of Mycology, Jinan UniversityGuangzhou, China
| | - Hao-Tian Wu
- The First Affiliated Hospital of Jinan UniversityGuangzhou, China; Institute of Mycology, Jinan UniversityGuangzhou, China
| | - Hui Guo
- The First Affiliated Hospital of Jinan UniversityGuangzhou, China; Institute of Mycology, Jinan UniversityGuangzhou, China
| | - Kun-Ju Zhu
- The First Affiliated Hospital of Jinan UniversityGuangzhou, China; Institute of Mycology, Jinan UniversityGuangzhou, China
| | - Dong-Mei Li
- Department of Microbiology and Immunology, Georgetown University Medical Center Washington, DC, USA
| | - Hong Zhang
- The First Affiliated Hospital of Jinan UniversityGuangzhou, China; Institute of Mycology, Jinan UniversityGuangzhou, China
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21
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Danhof HA, Vylkova S, Vesely EM, Ford AE, Gonzalez-Garay M, Lorenz MC. Robust Extracellular pH Modulation by Candida albicans during Growth in Carboxylic Acids. mBio 2016; 7:e01646-16. [PMID: 27935835 PMCID: PMC5111404 DOI: 10.1128/mbio.01646-16] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 10/24/2016] [Indexed: 12/25/2022] Open
Abstract
The opportunistic fungal pathogen Candida albicans thrives within diverse niches in the mammalian host. Among the adaptations that underlie this fitness is an ability to utilize a wide array of nutrients, especially sources of carbon that are disfavored by many other fungi; this contributes to its ability to survive interactions with the phagocytes that serve as key barriers against disseminated infections. We have reported that C. albicans generates ammonia as a byproduct of amino acid catabolism to neutralize the acidic phagolysosome and promote hyphal morphogenesis in a manner dependent on the Stp2 transcription factor. Here, we report that this species rapidly neutralizes acidic environments when utilizing carboxylic acids like pyruvate, α-ketoglutarate (αKG), or lactate as the primary carbon source. Unlike in cells growing in amino acid-rich medium, this does not result in ammonia release, does not induce hyphal differentiation, and is genetically distinct. While transcript profiling revealed significant similarities in gene expression in cells grown on either carboxylic or amino acids, genetic screens for mutants that fail to neutralize αKG medium identified a nonoverlapping set of genes, including CWT1, encoding a transcription factor responsive to cell wall and nitrosative stresses. Strains lacking CWT1 exhibit retarded αKG-mediated neutralization in vitro, exist in a more acidic phagolysosome, and are more susceptible to macrophage killing, while double cwt1Δ stp2Δ mutants are more impaired than either single mutant. Together, our observations indicate that C. albicans has evolved multiple ways to modulate the pH of host-relevant environments to promote its fitness as a pathogen. IMPORTANCE The fungal pathogen Candida albicans is a ubiquitous and usually benign constituent of the human microbial ecosystem. In individuals with weakened immune systems, this organism can cause potentially life-threatening infections and is one of the most common causes of hospital-acquired infections. Understanding the interactions between C. albicans and immune phagocytic cells, such as macrophages and neutrophils, will define the mechanisms of pathogenesis in this species. One such adaptation is an ability to make use of nonstandard nutrients that we predict are plentiful in certain niches within the host, including within these phagocytic cells. We show here that the metabolism of certain organic acids enables C. albicans to neutralize acidic environments, such as those within macrophages. This phenomenon is distinct in several significant ways from previous reports of similar processes, indicating that C. albicans has evolved multiple mechanisms to combat the harmful acidity of phagocytic cells.
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Affiliation(s)
- Heather A Danhof
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Slavena Vylkova
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Elisa M Vesely
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Amy E Ford
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Manuel Gonzalez-Garay
- The Brown Foundation Institute for Molecular Medicine, University of Texas Health Science Center at Houston, Houston, Texas, USA
| | - Michael C Lorenz
- Department of Microbiology and Molecular Genetics, McGovern Medical School, University of Texas Health Science Center at Houston, Houston, Texas, USA
- The Graduate School of Biomedical Sciences, University of Texas Health Science Center at Houston, Houston, Texas, USA
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22
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Candidalysin is a fungal peptide toxin critical for mucosal infection. Nature 2016; 532:64-8. [PMID: 27027296 PMCID: PMC4851236 DOI: 10.1038/nature17625] [Citation(s) in RCA: 572] [Impact Index Per Article: 71.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 02/26/2016] [Indexed: 01/23/2023]
Abstract
Cytolytic proteins and peptide toxins are classical virulence factors of several bacterial pathogens which disrupt epithelial barrier function, damage cells and activate or modulate host immune responses. Such toxins have not been identified previously in human pathogenic fungi. Here we identify the first, to our knowledge, fungal cytolytic peptide toxin in the opportunistic pathogen Candida albicans. This secreted toxin directly damages epithelial membranes, triggers a danger response signalling pathway and activates epithelial immunity. Membrane permeabilization is enhanced by a positive charge at the carboxy terminus of the peptide, which triggers an inward current concomitant with calcium influx. C. albicans strains lacking this toxin do not activate or damage epithelial cells and are avirulent in animal models of mucosal infection. We propose the name 'Candidalysin' for this cytolytic peptide toxin; a newly identified, critical molecular determinant of epithelial damage and host recognition of the clinically important fungus, C. albicans.
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23
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Pleiotropic effects of the vacuolar ABC transporter MLT1 of Candida albicans on cell function and virulence. Biochem J 2016; 473:1537-52. [PMID: 27026051 PMCID: PMC4888455 DOI: 10.1042/bcj20160024] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 03/29/2016] [Indexed: 01/14/2023]
Abstract
Among the several mechanisms that contribute to MDR (multidrug resistance), the overexpression of drug-efflux pumps belonging to the ABC (ATP-binding cassette) superfamily is the most frequent cause of resistance to antifungal agents. The multidrug transporter proteins Cdr1p and Cdr2p of the ABCG subfamily are major players in the development of MDR in Candida albicans. Because several genes coding for ABC proteins exist in the genome of C. albicans, but only Cdr1p and Cdr2p have established roles in MDR, it is implicit that the other members of the ABC family also have alternative physiological roles. The present study focuses on an ABC transporter of C. albicans, Mlt1p, which is localized in the vacuolar membrane and specifically transports PC (phosphatidylcholine) into the vacuolar lumen. Transcriptional profiling of the mlt1∆/∆ mutant revealed a down-regulation of the genes involved in endocytosis, oxidoreductase activity, virulence and hyphal development. High-throughput MS-based lipidome analysis revealed that the Mlt1p levels affect lipid homoeostasis and thus lead to a plethora of physiological perturbations. These include a delay in endocytosis, inefficient sequestering of reactive oxygen species (ROS), defects in hyphal development and attenuated virulence. The present study is an emerging example where new and unconventional roles of an ABC transporter are being identified.
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Höfs S, Mogavero S, Hube B. Interaction of Candida albicans with host cells: virulence factors, host defense, escape strategies, and the microbiota. J Microbiol 2016; 54:149-69. [DOI: 10.1007/s12275-016-5514-0] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 11/03/2015] [Accepted: 11/07/2015] [Indexed: 12/20/2022]
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Novel Aggregation Properties of Candida albicans Secreted Aspartyl Proteinase Sap6 Mediate Virulence in Oral Candidiasis. Infect Immun 2015; 83:2614-26. [PMID: 25870228 DOI: 10.1128/iai.00282-15] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Candida albicans, a commensal fungus of the oral microbiome, causes oral candidiasis in humans with localized or systemic immune deficiencies. Secreted aspartic proteinases (Saps) are a family of 10 related proteases and are virulence factors due to their proteolytic activity, as well as their roles in adherence and colonization of host tissues. We found that mice infected sublingually with C. albicans cells overexpressing Sap6 (SAP6 OE and a Δsap8 strain) had thicker fungal plaques and more severe oral infection, while infection with the Δsap6 strain was attenuated. These hypervirulent strains had highly aggregative colony structure in vitro and higher secreted proteinase activity; however, the levels of proteinase activity of C. albicans Saps did not uniformly match their abilities to damage cultured oral epithelial cells (SCC-15 cells). Hyphal induction in cells overexpressing Sap6 (SAP6 OE and Δsap8 cells) resulted in formation of large cell-cell aggregates. These aggregates could be produced in germinated wild-type cells by addition of native or heat-inactivated Sap6. Sap6 bound only to germinated cells and increased C. albicans adhesion to oral epithelial cells. The adhesion properties of Sap6 were lost upon deletion of its integrin-binding motif (RGD) and could be inhibited by addition of RGD peptide or anti-integrin antibodies. Thus, Sap6 (but not Sap5) has an alternative novel function in cell-cell aggregation, independent of its proteinase activity, to promote infection and virulence in oral candidiasis.
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26
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Abstract
Only few Candida species, e.g., Candida albicans, Candida glabrata, Candida dubliniensis, and Candida parapsilosis, are successful colonizers of a human host. Under certain circumstances these species can cause infections ranging from superficial to life-threatening disseminated candidiasis. The success of C. albicans, the most prevalent and best studied Candida species, as both commensal and human pathogen depends on its genetic, biochemical, and morphological flexibility which facilitates adaptation to a wide range of host niches. In addition, formation of biofilms provides additional protection from adverse environmental conditions. Furthermore, in many host niches Candida cells coexist with members of the human microbiome. The resulting fungal-bacterial interactions have a major influence on the success of C. albicans as commensal and also influence disease development and outcome. In this chapter, we review the current knowledge of important survival strategies of Candida spp., focusing on fundamental fitness and virulence traits of C. albicans.
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Affiliation(s)
- Melanie Polke
- Research Group Microbial Immunology, Hans-Knoell-Institute, Jena, Germany; Department Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany
| | - Bernhard Hube
- Department Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany; Friedrich-Schiller-University, Jena, Germany; Center for Sepsis Control and Care, Jena University Hospital, Jena, Germany
| | - Ilse D Jacobsen
- Research Group Microbial Immunology, Hans-Knoell-Institute, Jena, Germany; Friedrich-Schiller-University, Jena, Germany
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27
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Hube B, Hay R, Brasch J, Veraldi S, Schaller M. Dermatomycoses and inflammation: The adaptive balance between growth, damage, and survival. J Mycol Med 2015; 25:e44-58. [PMID: 25662199 DOI: 10.1016/j.mycmed.2014.11.002] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 11/14/2014] [Accepted: 11/18/2014] [Indexed: 11/26/2022]
Abstract
Dermatomycosis is characterized by both superficial and subcutaneous infections of keratinous tissues and mucous membranes caused by a variety of fungal agents, the two most common classes being dermatophytes and yeasts. Overall, the stepwise process of host infection is similar among the main dermatomycotic species; however, the species-specific ability to elicit a host reaction upon infection is distinct. Yeasts such as Candida albicans elicit a relatively low level of host tissue damage and inflammation during pathogenic infection, while dermatophytes may induce a higher level of tissue damage and inflammatory reaction. Both pathogens can, however, manipulate the host's immune response, ensuring survival and prolonging chronic infection. One common element of most dermatomycotic infections is the disease burden caused by inflammation and associated signs and symptoms, such as erythema, burning and pruritus. There is a strong clinical rationale for the addition of a topical corticosteroid agent to an effective antimycotic therapy, especially in patients who present with inflammatory dermatomycoses (e.g., tinea inguinalis). In this review, we aim to compare the pathogenesis of common dermatomycotic species, including Candida yeasts (Candida albicans), dermatophytes (Trichophyton, Epidermophyton or Microsporum species), and other pathogenic yeasts (Malassezia), with a special focus on unique species-specific aspects of the respective infection processes, the interaction between essential aspects of pathogenic infection, the different roles of the host inflammatory response, and the clinical consequences of the infection-related tissue damage and inflammation. We hope that a broader understanding of the various mechanisms of dermatomycoses may contribute to more effective management of affected patients.
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Affiliation(s)
- B Hube
- Department of Microbial Pathogenicity Mechanisms, Hans-Knöll-Institute (HKI), Leibniz Institute for Natural Product Research and Infection Biology, Jena, Germany; Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany; Friedrich Schiller University, Jena, Germany
| | - R Hay
- Skin Infection Clinic, Kings College Hospital NHS Foundation Trust, London, UK
| | - J Brasch
- Klinik für Dermatologie, Venerologie und Allergologie, Universitätsklinikum Schleswig-Holstein, Campus Kiel, Germany
| | - S Veraldi
- Department of Medical and Surgical Physiopathology and Transplantations, University of Milan, I.R.C.C.S. Foundation, Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - M Schaller
- Department of Dermatology, Eberhard Karls Universität Tübingen, 72076 Tübingen, Germany.
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28
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Wartenberg A, Linde J, Martin R, Schreiner M, Horn F, Jacobsen ID, Jenull S, Wolf T, Kuchler K, Guthke R, Kurzai O, Forche A, d'Enfert C, Brunke S, Hube B. Microevolution of Candida albicans in macrophages restores filamentation in a nonfilamentous mutant. PLoS Genet 2014; 10:e1004824. [PMID: 25474009 PMCID: PMC4256171 DOI: 10.1371/journal.pgen.1004824] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2014] [Accepted: 10/15/2014] [Indexed: 11/30/2022] Open
Abstract
Following antifungal treatment, Candida albicans, and other human pathogenic fungi can undergo microevolution, which leads to the emergence of drug resistance. However, the capacity for microevolutionary adaptation of fungi goes beyond the development of resistance against antifungals. Here we used an experimental microevolution approach to show that one of the central pathogenicity mechanisms of C. albicans, the yeast-to-hyphae transition, can be subject to experimental evolution. The C. albicans cph1Δ/efg1Δ mutant is nonfilamentous, as central signaling pathways linking environmental cues to hyphal formation are disrupted. We subjected this mutant to constant selection pressure in the hostile environment of the macrophage phagosome. In a comparatively short time-frame, the mutant evolved the ability to escape macrophages by filamentation. In addition, the evolved mutant exhibited hyper-virulence in a murine infection model and an altered cell wall composition compared to the cph1Δ/efg1Δ strain. Moreover, the transcriptional regulation of hyphae-associated, and other pathogenicity-related genes became re-responsive to environmental cues in the evolved strain. We went on to identify the causative missense mutation via whole genome- and transcriptome-sequencing: a single nucleotide exchange took place within SSN3 that encodes a component of the Cdk8 module of the Mediator complex, which links transcription factors with the general transcription machinery. This mutation was responsible for the reconnection of the hyphal growth program with environmental signals in the evolved strain and was sufficient to bypass Efg1/Cph1-dependent filamentation. These data demonstrate that even central transcriptional networks can be remodeled very quickly under appropriate selection pressure. Pathogenic microbes often evolve complex traits to adapt to their respective hosts, and this evolution is ongoing: for example, microorganisms are developing resistance to antimicrobial compounds in the clinical setting. The ability of the common human pathogenic fungus, Candida albicans, to switch from yeast to hyphal (filamentous) growth is considered a central virulence attribute. For example, hyphal formation allows C. albicans to escape from macrophages following phagocytosis. A well-investigated signaling network integrates different environmental cues to induce and maintain hyphal growth. In fact, deletion of two central transcription factors in this network results in a mutant that is both nonfilamentous and avirulent. We used experimental evolution to study the adaptation capability of this mutant by continuous co-incubation within macrophages. We found that this selection regime led to a relatively rapid re-connection of signaling between environmental cues and the hyphal growth program. Indeed, the evolved mutant regained the ability to filament and its virulence in vivo. This bypass of central transcription factors was based on a single nucleotide exchange in a gene encoding a component of the general transcription regulation machinery. Our results show that even a complex regulatory network, such as the transcriptional network which governs hyphal growth, can be remodeled via microevolution.
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Affiliation(s)
- Anja Wartenberg
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Jörg Linde
- Research Group Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Ronny Martin
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology –Hans Knoell Institute, Jena, Germany
| | - Maria Schreiner
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Fabian Horn
- Research Group Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Ilse D. Jacobsen
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Sabrina Jenull
- Medical University Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Vienna, Austria
| | - Thomas Wolf
- Research Group Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Karl Kuchler
- Medical University Vienna, Max F. Perutz Laboratories, Department of Medical Biochemistry, Vienna, Austria
| | - Reinhard Guthke
- Research Group Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Oliver Kurzai
- Septomics Research Center, Friedrich Schiller University and Leibniz Institute for Natural Product Research and Infection Biology –Hans Knoell Institute, Jena, Germany
| | - Anja Forche
- Department of Biology, Bowdoin College, Brunswick, Maine, United States of America
| | - Christophe d'Enfert
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), Universitätsklinikum Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), Universitätsklinikum Jena, Germany
- Friedrich Schiller University, Jena, Germany
- * E-mail:
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29
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Abstract
Fungal pathogens must assimilate local nutrients to establish an infection in their mammalian host. We focus on carbon, nitrogen, and micronutrient assimilation mechanisms, discussing how these influence host-fungus interactions during infection. We highlight several emerging trends based on the available data. First, the perturbation of carbon, nitrogen, or micronutrient assimilation attenuates fungal pathogenicity. Second, the contrasting evolutionary pressures exerted on facultative versus obligatory pathogens have led to contemporary pathogenic fungal species that display differing degrees of metabolic flexibility. The evolutionarily ancient metabolic pathways are conserved in most fungal pathogen, but interesting gaps exist in some species (e.g., Candida glabrata). Third, metabolic flexibility is generally essential for fungal pathogenicity, and in particular, for the adaptation to contrasting host microenvironments such as the gastrointestinal tract, mucosal surfaces, bloodstream, and internal organs. Fourth, this metabolic flexibility relies on complex regulatory networks, some of which are conserved across lineages, whereas others have undergone significant evolutionary rewiring. Fifth, metabolic adaptation affects fungal susceptibility to antifungal drugs and also presents exciting opportunities for the development of novel therapies.
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Affiliation(s)
- Iuliana V Ene
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany
| | - Alistair J P Brown
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany Friedrich Schiller University, 07743 Jena, Germany Center for Sepsis Control and Care, Universitätsklinikum Jena, 07747 Jena, Germany
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30
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Interplay between Candida albicans and the antimicrobial peptide armory. EUKARYOTIC CELL 2014; 13:950-7. [PMID: 24951441 DOI: 10.1128/ec.00093-14] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Antimicrobial peptides (AMPs) are key elements of innate immunity, which can directly kill multiple bacterial, viral, and fungal pathogens. The medically important fungus Candida albicans colonizes different host niches as part of the normal human microbiota. Proliferation of C. albicans is regulated through a complex balance of host immune defense mechanisms and fungal responses. Expression of AMPs against pathogenic fungi is differentially regulated and initiated by interactions of a variety of fungal pathogen-associated molecular patterns (PAMPs) with pattern recognition receptors (PRRs) on human cells. Inflammatory signaling and other environmental stimuli are also essential to control fungal proliferation and to prevent parasitism. To persist in the host, C. albicans has developed a three-phase AMP evasion strategy, including secretion of peptide effectors, AMP efflux pumps, and regulation of signaling pathways. These mechanisms prevent C. albicans from the antifungal activity of the major AMP classes, including cathelicidins, histatins, and defensins leading to a basal resistance. This minireview summarizes human AMP attack and C. albicans resistance mechanisms and current developments in the use of AMPs as antifungal agents.
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31
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Tao L, Du H, Guan G, Dai Y, Nobile CJ, Liang W, Cao C, Zhang Q, Zhong J, Huang G. Discovery of a "white-gray-opaque" tristable phenotypic switching system in candida albicans: roles of non-genetic diversity in host adaptation. PLoS Biol 2014; 12:e1001830. [PMID: 24691005 PMCID: PMC3972085 DOI: 10.1371/journal.pbio.1001830] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/21/2014] [Indexed: 11/19/2022] Open
Abstract
This study describes a novel “white-gray-opaque” tristable phenotypic switching system in the human fungal pathogen Candida albicans, revealing additional complexity in this organism's ability to adapt to changing environments. Non-genetic phenotypic variations play a critical role in the adaption to environmental changes in microbial organisms. Candida albicans, a major human fungal pathogen, can switch between several morphological phenotypes. This ability is critical for its commensal lifestyle and for its ability to cause infections. Here, we report the discovery of a novel morphological form in C. albicans, referred to as the “gray” phenotype, which forms a tristable phenotypic switching system with the previously reported white and opaque phenotypes. White, gray, and opaque cell types differ in a number of aspects including cellular and colony appearances, mating competency, secreted aspartyl proteinase (Sap) activities, and virulence. Of the three cell types, gray cells exhibit the highest Sap activity and the highest ability to cause cutaneous infections. The three phenotypes form a tristable phenotypic switching system, which is independent of the regulation of the mating type locus (MTL). Gray cells mate over 1,000 times more efficiently than do white cells, but less efficiently than do opaque cells. We further demonstrate that the master regulator of white-opaque switching, Wor1, is essential for opaque cell formation, but is not required for white-gray transitions. The Efg1 regulator is required for maintenance of the white phenotype, but is not required for gray-opaque transitions. Interestingly, the wor1/wor1 efg1/efg1 double mutant is locked in the gray phenotype, suggesting that Wor1 and Efg1 could function coordinately and play a central role in the regulation of gray cell formation. Global transcriptional analysis indicates that white, gray, and opaque cells exhibit distinct gene expression profiles, which partly explain their differences in causing infections, adaptation ability to diverse host niches, metabolic profiles, and stress responses. Therefore, the white-gray-opaque tristable phenotypic switching system in C. albicans may play a significant role in a wide range of biological aspects in this common commensal and pathogenic fungus. The capacity of the yeast Candida albicans to grow in several cellular forms—a phenomenon known as phenotypic plasticity—is critical for its survival and for its ability to thrive and cause infection in the human host. In this study, we report a novel form of C. albicans, the “gray” phenotype, which may enhance fitness and confer an adaptive advantage for this important pathogenic yeast in certain host environments. The gray cell type, together with the previously discovered “white” and “opaque” cell types, forms a tristable phenotypic switching system. The three phenotypes differ in their cellular and colony appearance, their global transcriptional profiles, their production of secreted aspartyl proteinases (enzymes that degrade host tissues and release nutrients), and their virulence in different infection models. Moreover, gray cells exhibit a level of mating competency that is intermediate between that of white and opaque cells. We further demonstrate that two key transcriptional regulators, Wor1 and Efg1, play central roles in the regulation of the “white-gray-opaque” tristable transitions. Our study reveals a multi-stable and heritable switching system, indicating that the adoption of distinct morphological forms in response to environmental change could be much more elaborate than previously thought.
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Affiliation(s)
- Li Tao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Han Du
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guobo Guan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Yu Dai
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Clarissa J. Nobile
- Department of Molecular and Cell Biology, School of Natural Sciences, University of California, Merced, Merced, California, United States of America
| | - Weihong Liang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Chengjun Cao
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiuyu Zhang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jin Zhong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Guanghua Huang
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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Ramachandra S, Linde J, Brock M, Guthke R, Hube B, Brunke S. Regulatory networks controlling nitrogen sensing and uptake in Candida albicans. PLoS One 2014; 9:e92734. [PMID: 24651113 PMCID: PMC3961412 DOI: 10.1371/journal.pone.0092734] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 02/24/2014] [Indexed: 12/22/2022] Open
Abstract
Nitrogen is one of the key nutrients for microbial growth. During infection, pathogenic fungi like C. albicans need to acquire nitrogen from a broad range of different and changing sources inside the host. Detecting the available nitrogen sources and adjusting the expression of genes for their uptake and degradation is therefore crucial for survival and growth as well as for establishing an infection. Here, we analyzed the transcriptional response of C. albicans to nitrogen starvation and feeding with the infection-relevant nitrogen sources arginine and bovine serum albumin (BSA), representing amino acids and proteins, respectively. The response to nitrogen starvation was marked by an immediate repression of protein synthesis and an up-regulation of general amino acid permeases, as well as an up-regulation of autophagal processes in its later stages. Feeding with arginine led to a fast reduction in expression of general permeases for amino acids and to resumption of protein synthesis. The response to BSA feeding was generally slower, and was additionally characterized by an up-regulation of oligopeptide transporter genes. From time-series data, we inferred network interaction models for genes relevant in nitrogen detection and uptake. Each individual network was found to be largely specific for the experimental condition (starvation or feeding with arginine or BSA). In addition, we detected several novel connections between regulator and effector genes, with putative roles in nitrogen uptake. We conclude that C. albicans adopts a particular nitrogen response network, defined by sets of specific gene-gene connections for each environmental condition. All together, they form a grid of possible gene regulatory networks, increasing the transcriptional flexibility of C. albicans.
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Affiliation(s)
- Shruthi Ramachandra
- Department of Microbial Biochemistry and Physiology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Jörg Linde
- Department of Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Matthias Brock
- Department of Microbial Biochemistry and Physiology, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Reinhard Guthke
- Department of Systems Biology & Bioinformatics, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Jena, Germany
- * E-mail:
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Distinct roles of Candida albicans-specific genes in host-pathogen interactions. EUKARYOTIC CELL 2014; 13:977-89. [PMID: 24610660 DOI: 10.1128/ec.00051-14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Human fungal pathogens are distributed throughout their kingdom, suggesting that pathogenic potential evolved independently. Candida albicans is the most virulent member of the CUG clade of yeasts and a common cause of both superficial and invasive infections. We therefore hypothesized that C. albicans possesses distinct pathogenicity mechanisms. In silico genome subtraction and comparative transcriptional analysis identified a total of 65 C. albicans-specific genes (ASGs) expressed during infection. Phenotypic characterization of six ASG-null mutants demonstrated that these genes are dispensable for in vitro growth but play defined roles in host-pathogen interactions. Based on these analyses, we investigated two ASGs in greater detail. An orf19.6688Δ mutant was found to be fully virulent in a mouse model of disseminated candidiasis and to induce higher levels of the proinflammatory cytokine interleukin-1β (IL-1β) following incubation with murine macrophages. A pga16Δ mutant, on the other hand, exhibited attenuated virulence. Moreover, we provide evidence that secondary filamentation events (multiple hyphae emerging from a mother cell and hyphal branching) contribute to pathogenicity: PGA16 deletion did not influence primary hypha formation or extension following contact with epithelial cells; however, multiple hyphae and hyphal branching were strongly reduced. Significantly, these hyphae failed to damage host cells as effectively as the multiple hypha structures formed by wild-type C. albicans cells. Together, our data show that species-specific genes of a eukaryotic pathogen can play important roles in pathogenicity.
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Costa C, Nunes J, Henriques A, Mira NP, Nakayama H, Chibana H, Teixeira MC. Candida glabrata drug:H+ antiporter CgTpo3 (ORF CAGL0I10384g): role in azole drug resistance and polyamine homeostasis. J Antimicrob Chemother 2014; 69:1767-76. [PMID: 24576949 DOI: 10.1093/jac/dku044] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
OBJECTIVES The ability of opportunistic pathogenic Candida species to persist and invade specific niches in the human host depends on their resistance to natural growth inhibitors and antifungal therapy. This work describes the role of the Candida glabrata drug:H(+) antiporter CgTpo3 (ORF CAGL0I10384g) in this context. METHODS Deletion and cloning of CgTPO3 was achieved using molecular biology tools. C. glabrata strain susceptibility was assayed based on growth in liquid and solid media and through MIC determination. Radiolabelled compound accumulation or HPLC were used for the assessment of the role of CgTpo3 as a drug or polyamine transporter. Quantitative RT-PCR was used for expression analysis. RESULTS CgTpo3 was found to confer resistance to azole drugs in C. glabrata. This protein was found to be localized to the plasma membrane and to decrease the intracellular accumulation of [(3)H]clotrimazole, playing a direct role in its extrusion from pre-loaded C. glabrata cells. CgTPO3 was further found to confer resistance to spermine, complementing the susceptibility phenotypes exhibited by the deletion of its Saccharomyces cerevisiae homologue, TPO3. In spermine-stressed C. glabrata cells, CgTPO3 is transcriptionally activated in a CgPdr1-dependent manner, contributing to a decrease in the intracellular concentration of this polyamine. Clotrimazole exposure was found to lead to the intracellular accumulation of spermine, and pre-exposure to this polyamine was found consistently to lead to increased clotrimazole resistance. CONCLUSIONS Altogether, these results point to a significant role for CgTpo3 in azole drug resistance and in the tolerance to high polyamine concentrations, such as those found in the urogenital tract.
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Affiliation(s)
- Catarina Costa
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal IBB - Institute for Biotechnology and Bioengineering, Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisboa, Portugal
| | - Joana Nunes
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal IBB - Institute for Biotechnology and Bioengineering, Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisboa, Portugal
| | - André Henriques
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal IBB - Institute for Biotechnology and Bioengineering, Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisboa, Portugal
| | - Nuno P Mira
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal IBB - Institute for Biotechnology and Bioengineering, Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisboa, Portugal
| | - Hironobu Nakayama
- Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan
| | - Hiroji Chibana
- Medical Mycology Research Center (MMRC), Chiba University, Chiba, Japan
| | - Miguel C Teixeira
- Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, Lisboa, Portugal IBB - Institute for Biotechnology and Bioengineering, Biological Sciences Research Group, Centre for Biological and Chemical Engineering, Instituto Superior Técnico, Lisboa, Portugal
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Affiliation(s)
- Scott G Filler
- Los Angeles Biomedical Research Institute at Harbor; UCLA Medical Center; Torrance, CA USA; The David Geffen School of Medicine at UCLA; Los Angeles, CA USA
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Moyes DL, Shen C, Murciano C, Runglall M, Richardson JP, Arno M, Aldecoa-Otalora E, Naglik JR. Protection against epithelial damage during Candida albicans infection is mediated by PI3K/Akt and mammalian target of rapamycin signaling. J Infect Dis 2013; 209:1816-26. [PMID: 24357630 PMCID: PMC4017362 DOI: 10.1093/infdis/jit824] [Citation(s) in RCA: 71] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Background. The ability of epithelial cells (ECs) to discriminate between commensal and pathogenic microbes is essential for healthy living. Key to these interactions are mucosal epithelial responses to pathogen-induced damage. Methods. Using reconstituted oral epithelium, we assessed epithelial gene transcriptional responses to Candida albicans infection by microarray. Signal pathway activation was monitored by Western blotting and transcription factor enzyme-linked immunosorbent assay, and the role of these pathways in C. albicans–induced damage protection was determined using chemical inhibitors. Results. Transcript profiling demonstrated early upregulation of epithelial genes involved in immune responses. Many of these genes constituted components of signaling pathways, but only NF-κB, MAPK, and PI3K/Akt pathways were functionally activated. We demonstrate that PI3K/Akt signaling is independent of NF-κB and MAPK signaling and plays a key role in epithelial immune activation and damage protection via mammalian target of rapamycin (mTOR) activation. Conclusions. PI3K/Akt/mTOR signaling may play a critical role in protecting epithelial cells from damage during mucosal fungal infections independent of NF-κB or MAPK signaling.
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Affiliation(s)
- David L Moyes
- Department of Oral Immunology, King's College London Dental Institute
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Castelhano Santos N, Pereira MO, Lourenço A. Pathogenicity phenomena in three model systems: from network mining to emerging system-level properties. Brief Bioinform 2013; 16:169-82. [PMID: 24106130 DOI: 10.1093/bib/bbt071] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Understanding the interconnections of microbial pathogenicity phenomena, such as biofilm formation, quorum sensing and antimicrobial resistance, is a tremendous open challenge for biomedical research. Progress made by wet-lab researchers and bioinformaticians in understanding the underlying regulatory phenomena has been significant, with converging evidence from multiple high-throughput technologies. Notably, network reconstructions are already of considerable size and quality, tackling both intracellular regulation and signal mediation in microbial infection. Therefore, it stands to reason that in silico investigations would play a more active part in this research. Drug target identification and drug repurposing could take much advantage of the ability to simulate pathogen regulatory systems, host-pathogen interactions and pathogen cross-talking. Here, we review the bioinformatics resources and tools available for the study of the gram-negative bacterium Pseudomonas aeruginosa, the gram-positive bacterium Staphylococcus aureus and the fungal species Candida albicans. The choice of these three microorganisms fits the rationale of the review converging into pathogens of great clinical importance, which thrive in biofilm consortia and manifest growing antimicrobial resistance.
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Tati S, Jang WS, Li R, Kumar R, Puri S, Edgerton M. Histatin 5 resistance of Candida glabrata can be reversed by insertion of Candida albicans polyamine transporter-encoding genes DUR3 and DUR31. PLoS One 2013; 8:e61480. [PMID: 23613860 PMCID: PMC3632557 DOI: 10.1371/journal.pone.0061480] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 03/11/2013] [Indexed: 12/29/2022] Open
Abstract
Candida albicans and Candida glabrata are predominant fungi associated with oral candidiasis. Histatin 5 (Hst 5) is a small cationic human salivary peptide with high fungicidal activity against C. albicans, however many strains of C. glabrata are resistant. Since Hst 5 requires fungal binding to cell wall components prior to intracellular translocation, reduced Hst 5 binding to C. glabrata may be the reason for its insensitivity. C. glabrata has higher surface levels of β-1,3-glucans as compared with C. albicans; however these differences did not account for reduced Hst 5 uptake and killing in C. glabrata. Similarly, the biofilm matrix of C. glabrata contained significantly higher levels of β-1,3-glucans compared with C. albicans, but it did not reduce the percentage of Hst 5 positive fungal cells in the biofilm. Hst 5 enters C. albicans cell through polyamine transporters Dur3p and Dur31p that are uncharacterized in C. glabrata. C. glabrata strains expressing CaDur3 and CaDur31 had two-fold higher killing and uptake of Hst 5. Thus, neither C. glabrata cell surface or biofilm matrix β-1,3-glucan levels affected Hst 5 toxicity; rather the crucial rate limiting step is reduced uptake that can be overcome by expression of C. albicans Dur proteins in C. glabrata.
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Affiliation(s)
- Swetha Tati
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America
| | - Woong Sik Jang
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America
| | - Rui Li
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America
| | - Rohitashw Kumar
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America
| | - Sumant Puri
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America
| | - Mira Edgerton
- Department of Oral Biology, University at Buffalo, Buffalo, New York, United States of America
- * E-mail:
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Abstract
The polymorphic fungus Candida albicans is a member of the normal human microbiome. In most individuals, C. albicans resides as a lifelong, harmless commensal. Under certain circumstances, however, C. albicans can cause infections that range from superficial infections of the skin to life-threatening systemic infections. Several factors and activities have been identified which contribute to the pathogenic potential of this fungus. Among them are molecules which mediate adhesion to and invasion into host cells, the secretion of hydrolases, the yeast-to-hypha transition, contact sensing and thigmotropism, biofilm formation, phenotypic switching and a range of fitness attributes. Our understanding of when and how these mechanisms and factors contribute to infection has significantly increased during the last years. In addition, novel virulence mechanisms have recently been discovered. In this review we present an update on our current understanding of the pathogenicity mechanisms of this important human pathogen.
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Affiliation(s)
- François L Mayer
- Department of Microbial Pathogenicity Mechanisms, Hans-Knoell-Institute, Jena, Germany
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