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Shantal CJN, Juan CC, Lizbeth BUS, Carlos HGJ, Estela GPB. Candida glabrata is a successful pathogen: an artist manipulating the immune response. Microbiol Res 2022; 260:127038. [DOI: 10.1016/j.micres.2022.127038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 04/02/2022] [Accepted: 04/07/2022] [Indexed: 02/07/2023]
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Van Ende M, Timmermans B, Vanreppelen G, Siscar-Lewin S, Fischer D, Wijnants S, Romero CL, Yazdani S, Rogiers O, Demuyser L, Van Zeebroeck G, Cen Y, Kuchler K, Brunke S, Van Dijck P. The involvement of the Candida glabrata trehalase enzymes in stress resistance and gut colonization. Virulence 2021; 12:329-345. [PMID: 33356857 PMCID: PMC7808424 DOI: 10.1080/21505594.2020.1868825] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2020] [Revised: 11/28/2020] [Accepted: 12/17/2020] [Indexed: 12/29/2022] Open
Abstract
Candida glabrata is an opportunistic human fungal pathogen and is frequently present in the human microbiome. It has a high relative resistance to environmental stresses and several antifungal drugs. An important component involved in microbial stress tolerance is trehalose. In this work, we characterized the three C. glabrata trehalase enzymes Ath1, Nth1 and Nth2. Single, double and triple deletion strains were constructed and characterized both in vitro and in vivo to determine the role of these enzymes in virulence. Ath1 was found to be located in the periplasm and was essential for growth on trehalose as sole carbon source, while Nth1 on the other hand was important for oxidative stress resistance, an observation which was consistent by the lower survival rate of the NTH1 deletion strain in human macrophages. No significant phenotype was observed for Nth2. The triple deletion strain was unable to establish a stable colonization of the gastrointestinal (GI) tract in mice indicating the importance of having trehalase activity for colonization in the gut.
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Affiliation(s)
- Mieke Van Ende
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Bea Timmermans
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Giel Vanreppelen
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Sofía Siscar-Lewin
- Department of Microbial Pathogenicity Mechanisms, Hans Knöll Institute, Jena, Germany
| | - Daniel Fischer
- Department of Microbial Pathogenicity Mechanisms, Hans Knöll Institute, Jena, Germany
| | - Stefanie Wijnants
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Celia Lobo Romero
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Saleh Yazdani
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Ona Rogiers
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
- Department of Internal Medicine and Pediatrics, Ghent University, Ghent, Belgium
- VIB-UGent Center for Inflammation Research, Ghent, VIB, Belgium
| | - Liesbeth Demuyser
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Griet Van Zeebroeck
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Yuke Cen
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
| | - Karl Kuchler
- Medical University of Vienna, Center for Medical Biochemistry, Max Perutz Labs Vienna, Campus Vienna Biocenter, Vienna, Austria
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knöll Institute, Jena, Germany
| | - Patrick Van Dijck
- Laboratory of Molecular Cell Biology, Department of Biology, Institute of Botany and Microbiology, Leuven, KU Leuven, Belgium
- VIB-KU Leuven Center for Microbiology, Leuven, Belgium
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3
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Survival Strategies of Pathogenic Candida Species in Human Blood Show Independent and Specific Adaptations. mBio 2020; 11:mBio.02435-20. [PMID: 33024045 PMCID: PMC7542370 DOI: 10.1128/mbio.02435-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
To ensure their survival, pathogens have to adapt immediately to new environments in their hosts, for example, during the transition from the gut to the bloodstream. Here, we investigated the basis of this adaptation in a group of fungal species which are among the most common causes of hospital-acquired infections, the Candida species. On the basis of a human whole-blood infection model, we studied which genes and processes are active over the course of an infection in both the host and four different Candida pathogens. Remarkably, we found that, while the human host response during the early phase of infection is predominantly uniform, the pathogens pursue largely individual strategies and each one regulates genes involved in largely disparate processes in the blood. Our results reveal that C. albicans, C. glabrata, C. parapsilosis, and C. tropicalis all have developed individual strategies for survival in the host. This indicates that their pathogenicity in humans has evolved several times independently and that genes which are central for survival in the host for one species may be irrelevant in another. Only four species, Candida albicans, C. glabrata, C. parapsilosis, and C. tropicalis, together account for about 90% of all Candida bloodstream infections and are among the most common causes of invasive fungal infections of humans. However, virulence potential varies among these species, and the phylogenetic tree reveals that their pathogenicity may have emerged several times independently during evolution. We therefore tested these four species in a human whole-blood infection model to determine, via comprehensive dual-species RNA-sequencing analyses, which fungal infection strategies are conserved and which are recent evolutionary developments. The ex vivo infection progressed from initial immune cell interactions to nearly complete killing of all fungal cells. During the course of infection, we characterized important parameters of pathogen-host interactions, such as fungal survival, types of interacting immune cells, and cytokine release. On the transcriptional level, we obtained a predominantly uniform and species-independent human response governed by a strong upregulation of proinflammatory processes, which was downregulated at later time points after most of the fungal cells were killed. In stark contrast, we observed that the different fungal species pursued predominantly individual strategies and showed significantly different global transcriptome patterns. Among other findings, our functional analyses revealed that the fungal species relied on different metabolic pathways and virulence factors to survive the host-imposed stress. These data show that adaptation of Candida species as a response to the host is not a phylogenetic trait, but rather has likely evolved independently as a prerequisite to cause human infections.
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Alder-Rangel A, Idnurm A, Brand AC, Brown AJP, Gorbushina A, Kelliher CM, Campos CB, Levin DE, Bell-Pedersen D, Dadachova E, Bauer FF, Gadd GM, Braus GH, Braga GUL, Brancini GTP, Walker GM, Druzhinina I, Pócsi I, Dijksterhuis J, Aguirre J, Hallsworth JE, Schumacher J, Wong KH, Selbmann L, Corrochano LM, Kupiec M, Momany M, Molin M, Requena N, Yarden O, Cordero RJB, Fischer R, Pascon RC, Mancinelli RL, Emri T, Basso TO, Rangel DEN. The Third International Symposium on Fungal Stress - ISFUS. Fungal Biol 2020; 124:235-252. [PMID: 32389286 DOI: 10.1016/j.funbio.2020.02.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Accepted: 02/11/2020] [Indexed: 12/19/2022]
Abstract
Stress is a normal part of life for fungi, which can survive in environments considered inhospitable or hostile for other organisms. Due to the ability of fungi to respond to, survive in, and transform the environment, even under severe stresses, many researchers are exploring the mechanisms that enable fungi to adapt to stress. The International Symposium on Fungal Stress (ISFUS) brings together leading scientists from around the world who research fungal stress. This article discusses presentations given at the third ISFUS, held in São José dos Campos, São Paulo, Brazil in 2019, thereby summarizing the state-of-the-art knowledge on fungal stress, a field that includes microbiology, agriculture, ecology, biotechnology, medicine, and astrobiology.
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Affiliation(s)
| | - Alexander Idnurm
- School of BioSciences, The University of Melbourne, VIC, Australia
| | - Alexandra C Brand
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, England, UK
| | - Alistair J P Brown
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Exeter, England, UK
| | - Anna Gorbushina
- Bundesanstalt für Materialforschung und -prüfung, Materials and the Environment, Berlin, Germany
| | - Christina M Kelliher
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Claudia B Campos
- Departamento de Ciência e Tecnologia, Universidade Federal de São Paulo, São José dos Campos, SP, Brazil
| | - David E Levin
- Boston University Goldman School of Dental Medicine, Boston, MA, USA
| | - Deborah Bell-Pedersen
- Center for Biological Clocks Research, Department of Biology, Texas A&M University, College Station, TX, USA
| | - Ekaterina Dadachova
- College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
| | - Florian F Bauer
- Institute for Wine Biotechnology, Department of Viticulture and Oenology, Stellenbosch University, Matieland, South Africa
| | - Geoffrey M Gadd
- Geomicrobiology Group, School of Life Sciences, University of Dundee, Dundee, Scotland, UK
| | - Gerhard H Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics and Goettingen Center for Molecular Biosciences, Georg-August-Universität Göttingen, Göttingen, Germany
| | - Gilberto U L Braga
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Guilherme T P Brancini
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, SP, Brazil
| | - Graeme M Walker
- School of Applied Sciences, Abertay University, Dundee, Scotland, UK
| | | | - István Pócsi
- Department of Molecular Biotechnology and Microbiology, University of Debrecen, Debrecen, Hungary
| | - Jan Dijksterhuis
- Westerdijk Fungal Biodiversity Institute, Utrecht, the Netherlands
| | - Jesús Aguirre
- Departamento de Biología Celular y del Desarrollo, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - John E Hallsworth
- Institute for Global Food Security, School of Biological Sciences, Queen's University Belfast, Belfast, Northern Ireland, UK
| | - Julia Schumacher
- Bundesanstalt für Materialforschung und -prüfung, Materials and the Environment, Berlin, Germany
| | - Koon Ho Wong
- Faculty of Health Sciences, University of Macau, Avenida da Universidade, Taipa, Macau SAR, China
| | - Laura Selbmann
- Department of Ecological and Biological Sciences, University of Tuscia, Viterbo, Italy; Italian National Antarctic Museum (MNA), Mycological Section, Genoa, Italy
| | | | - Martin Kupiec
- School of Molecular Cell Biology and Biotechnology, Tel Aviv University, Tel Aviv, Israel
| | - Michelle Momany
- Fungal Biology Group & Plant Biology Department, University of Georgia, Athens, GA, USA
| | - Mikael Molin
- Department of Biology and Biological Engineering, Chalmers University of Technology, Gothenburg, Sweden
| | - Natalia Requena
- Molecular Phytopathology Department, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Oded Yarden
- Department of Plant Pathology and Microbiology, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jeruslaem, Rehovot 7610001, Israel
| | - Radamés J B Cordero
- Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, 21205, USA
| | - Reinhard Fischer
- Department of Microbiology, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany
| | - Renata C Pascon
- Biological Sciences Department, Universidade Federal de São Paulo, Diadema, SP, Brazil
| | | | - Tamas Emri
- Department of Molecular Biotechnology and Microbiology, University of Debrecen, Debrecen, Hungary
| | - Thiago O Basso
- Department of Chemical Engineering, Escola Politécnica, Universidade de São Paulo, São Paulo, SP, Brazil
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Bouklas T, Alonso-Crisóstomo L, Székely T, Diago-Navarro E, Orner EP, Smith K, Munshi MA, Del Poeta M, Balázsi G, Fries BC. Generational distribution of a Candida glabrata population: Resilient old cells prevail, while younger cells dominate in the vulnerable host. PLoS Pathog 2017; 13:e1006355. [PMID: 28489916 PMCID: PMC5440053 DOI: 10.1371/journal.ppat.1006355] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 05/22/2017] [Accepted: 04/15/2017] [Indexed: 12/15/2022] Open
Abstract
Similar to other yeasts, the human pathogen Candida glabrata ages when it undergoes asymmetric, finite cell divisions, which determines its replicative lifespan. We sought to investigate if and how aging changes resilience of C. glabrata populations in the host environment. Our data demonstrate that old C. glabrata are more resistant to hydrogen peroxide and neutrophil killing, whereas young cells adhere better to epithelial cell layers. Consequently, virulence of old compared to younger C. glabrata cells is enhanced in the Galleria mellonella infection model. Electron microscopy images of old C. glabrata cells indicate a marked increase in cell wall thickness. Comparison of transcriptomes of old and young C. glabrata cells reveals differential regulation of ergosterol and Hog pathway associated genes as well as adhesion proteins, and suggests that aging is accompanied by remodeling of the fungal cell wall. Biochemical analysis supports this conclusion as older cells exhibit a qualitatively different lipid composition, leading to the observed increased emergence of fluconazole resistance when grown in the presence of fluconazole selection pressure. Older C. glabrata cells accumulate during murine and human infection, which is statistically unlikely without very strong selection. Therefore, we tested the hypothesis that neutrophils constitute the predominant selection pressure in vivo. When we altered experimentally the selection pressure by antibody-mediated removal of neutrophils, we observed a significantly younger pathogen population in mice. Mathematical modeling confirmed that differential selection of older cells is sufficient to cause the observed demographic shift in the fungal population. Hence our data support the concept that pathogenesis is affected by the generational age distribution of the infecting C. glabrata population in a host. We conclude that replicative aging constitutes an emerging trait, which is selected by the host and may even play an unanticipated role in the transition from a commensal to a pathogen state.
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Affiliation(s)
- Tejas Bouklas
- Department of Medicine, Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, United States of America
- Department of Biomedical Sciences, Long Island University-Post, Brookville, New York, United States of America
| | | | - Tamás Székely
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York, United States of America
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Elizabeth Diago-Navarro
- Department of Medicine, Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, United States of America
| | - Erika P. Orner
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Kalie Smith
- Department of Medicine, Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, United States of America
| | - Mansa A. Munshi
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
| | - Maurizio Del Poeta
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
- Veterans Administration Medical Center, Northport, New York, United States of America
| | - Gábor Balázsi
- The Louis and Beatrice Laufer Center for Physical and Quantitative Biology, Stony Brook University, Stony Brook, New York, United States of America
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America
| | - Bettina C. Fries
- Department of Medicine, Division of Infectious Diseases, Stony Brook University, Stony Brook, New York, United States of America
- Department of Molecular Genetics and Microbiology, Stony Brook University, Stony Brook, New York, United States of America
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Glass KA, Longley SJ, Bliss JM, Shaw SK. Protection of Candida parapsilosis from neutrophil killing through internalization by human endothelial cells. Virulence 2016; 6:504-14. [PMID: 26039751 DOI: 10.1080/21505594.2015.1042643] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Candida parapsilosis is a fungal pathogen that is associated with hematogenously disseminated disease in premature neonates, acutely ill or immunocompromised patients. In cell culture, C. parapsilosis cells are actively and avidly endocytosed by endothelial cells via actin polymerization mediated by N-WASP. Here we present evidence that C. parapsilosis that were internalized by endothelial cells remained alive, and avoided being acidified or otherwise damaged via the host cell. Internalized fungal cells reproduced intracellularly and eventually burst out of the host endothelial cell. When neutrophils were added to endothelium and C. parapsilosis, they patrolled the endothelial surface and efficiently killed most adherent fungal cells prior to endocytosis. But after endocytosis by endothelial cells, internalized fungal cells evaded neutrophil killing. Silencing endothelial N-WASP blocked endocytosis of C. parapsilosis and left fungal cells stranded on the cell surface, where they were susceptible to neutrophil killing. These observations suggest that for C. parapsilosis to escape from the bloodstream, fungi may adhere to and be internalized by endothelial cells before being confronted and phagocytosed by a patrolling leukocyte. Once internalized by endothelial cells, C. parapsilosis may safely replicate to cause further rounds of infection. Immunosurveillance of the intravascular lumen by leukocytes crawling on the endothelial surface and rapid killing of adherent yeast may play a major role in controlling C. parapsilosis dissemination and infected endothelial cells may be a significant reservoir for fungal persistence.
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Affiliation(s)
- Kyle A Glass
- a Department of Pediatrics; Women & Infants Hospital of Rhode Island ; Providence , RI , USA
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Mota S, Alves R, Carneiro C, Silva S, Brown AJ, Istel F, Kuchler K, Sampaio P, Casal M, Henriques M, Paiva S. Candida glabrata susceptibility to antifungals and phagocytosis is modulated by acetate. Front Microbiol 2015; 6:919. [PMID: 26388859 PMCID: PMC4560035 DOI: 10.3389/fmicb.2015.00919] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/21/2015] [Indexed: 11/13/2022] Open
Abstract
Candida glabrata is considered a major opportunistic fungal pathogen of humans. The capacity of this yeast species to cause infections is dependent on the ability to grow within the human host environment and to assimilate the carbon sources available. Previous studies have suggested that C. albicans can encounter glucose-poor microenvironments during infection and that the ability to use alternative non-fermentable carbon sources, such as carboxylic acids, contributes to the virulence of this fungus. Transcriptional studies on C. glabrata cells identified a similar response, upon nutrient deprivation. In this work, we aimed at analyzing biofilm formation, antifungal drug resistance, and phagocytosis of C. glabrata cells grown in the presence of acetic acid as an alternative carbon source. C. glabrata planktonic cells grown in media containing acetic acid were more susceptible to fluconazole and were better phagocytosed and killed by macrophages than when compared to media lacking acetic acid. Growth in acetic acid also affected the ability of C. glabrata to form biofilms. The genes ADY2a, ADY2b, FPS1, FPS2, and ATO3, encoding putative carboxylate transporters, were upregulated in C. glabrata planktonic and biofilm cells in the presence of acetic acid. Phagocytosis assays with fps1 and ady2a mutant strains suggested a potential role of FPS1 and ADY2a in the phagocytosis process. These results highlight how acidic pH niches, associated with the presence of acetic acid, can impact in the treatment of C. glabrata infections, in particular in vaginal candidiasis.
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Affiliation(s)
- Sandra Mota
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho Braga, Portugal ; Centre of Health and Environmental Research, School of Allied Health Sciences, Polytechnic Institute of Porto Porto, Portugal
| | - Rosana Alves
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho Braga, Portugal
| | - Catarina Carneiro
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho Braga, Portugal
| | - Sónia Silva
- Centre for Biological Engineering, University of Minho Braga, Portugal
| | - Alistair J Brown
- Institute of Medical Sciences - School of Medical Sciences, University of Aberdeen Aberdeen, UK
| | - Fabian Istel
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna Vienna, Austria
| | - Karl Kuchler
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University of Vienna Vienna, Austria
| | - Paula Sampaio
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho Braga, Portugal
| | - Margarida Casal
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho Braga, Portugal
| | - Mariana Henriques
- Centre for Biological Engineering, University of Minho Braga, Portugal
| | - Sandra Paiva
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho Braga, Portugal
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Kasper L, Seider K, Hube B. Intracellular survival of Candida glabrata in macrophages: immune evasion and persistence. FEMS Yeast Res 2015; 15:fov042. [PMID: 26066553 DOI: 10.1093/femsyr/fov042] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/05/2015] [Indexed: 12/11/2022] Open
Abstract
Candida glabrata is a successful human opportunistic pathogen which causes superficial but also life-threatening systemic infections. During infection, C. glabrata has to cope with cells of the innate immune system such as macrophages, which belong to the first line of defense against invading pathogens. Candida glabrata is able to survive and even replicate inside macrophages while causing surprisingly low damage and cytokine release. Here, we present an overview of recent studies dealing with the interaction of C. glabrata with macrophages, from phagocytosis to intracellular growth and escape. We review the strategies of C. glabrata that permit intracellular survival and replication, including poor host cell activation, modification of phagosome maturation and phagosome pH, adaptation to antimicrobial activities, and mechanisms to overcome the nutrient limitations within the phagosome. In summary, these studies suggest that survival within macrophages may be an immune evasion and persistence strategy of C. glabrata during infection.
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Affiliation(s)
- Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, 07745 Jena, Germany
| | - Katja Seider
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, 07745 Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, 07745 Jena, Germany Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), University Hospital, 07747 Jena, Germany Friedrich Schiller University, 07743 Jena, Germany
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Vale-Silva LA, Sanglard D. Tipping the balance both ways: drug resistance and virulence in Candida glabrata. FEMS Yeast Res 2015; 15:fov025. [PMID: 25979690 DOI: 10.1093/femsyr/fov025] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/11/2015] [Indexed: 01/20/2023] Open
Abstract
Among existing fungal pathogens, Candida glabrata is outstanding in its capacity to rapidly develop resistance to currently used antifungal agents. Resistance to the class of azoles, which are still widely used agents, varies in proportion (from 5 to 20%) depending on geographical area. Moreover, resistance to the class of echinocandins, which was introduced in the late 1990s, is rising in several institutions. The recent emergence of isolates with acquired resistance to both classes of agents is a major concern since alternative therapeutic options are scarce. Although considered less pathogenic than C. albicans, C. glabrata has still evolved specific virulence traits enabling its survival and propagation in colonized and infected hosts. Development of drug resistance is usually associated with fitness costs, and this notion is documented across several microbial species. Interestingly, azole resistance in C. glabrata has revealed the opposite. Experimental models of infection showed enhanced virulence of azole-resistant isolates. Moreover, azole resistance could be associated with specific changes in adherence properties to epithelial cells or innate immunity cells (macrophages), both of which contribute to virulence changes. Here we will summarize the current knowledge on C. glabrata drug resistance and also discuss the consequences of drug resistance acquisition on the balance between C. glabrata and its hosts.
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Affiliation(s)
- Luis A Vale-Silva
- Institute of Microbiology, University of Lausanne and University Hospital Center, CH-1011 Lausanne, Switzerland
| | - Dominique Sanglard
- Institute of Microbiology, University of Lausanne and University Hospital Center, CH-1011 Lausanne, Switzerland
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10
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Brunke S, Seider K, Fischer D, Jacobsen ID, Kasper L, Jablonowski N, Wartenberg A, Bader O, Enache-Angoulvant A, Schaller M, d'Enfert C, Hube B. One small step for a yeast--microevolution within macrophages renders Candida glabrata hypervirulent due to a single point mutation. PLoS Pathog 2014; 10:e1004478. [PMID: 25356907 PMCID: PMC4214790 DOI: 10.1371/journal.ppat.1004478] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 09/17/2014] [Indexed: 12/25/2022] Open
Abstract
Candida glabrata is one of the most common causes of candidemia, a life-threatening, systemic fungal infection, and is surpassed in frequency only by Candida albicans. Major factors contributing to the success of this opportunistic pathogen include its ability to readily acquire resistance to antifungals and to colonize and adapt to many different niches in the human body. Here we addressed the flexibility and adaptability of C. glabrata during interaction with macrophages with a serial passage approach. Continuous co-incubation of C. glabrata with a murine macrophage cell line for over six months resulted in a striking alteration in fungal morphology: The growth form changed from typical spherical yeasts to pseudohyphae-like structures – a phenotype which was stable over several generations without any selective pressure. Transmission electron microscopy and FACS analyses showed that the filamentous-like morphology was accompanied by changes in cell wall architecture. This altered growth form permitted faster escape from macrophages and increased damage of macrophages. In addition, the evolved strain (Evo) showed transiently increased virulence in a systemic mouse infection model, which correlated with increased organ-specific fungal burden and inflammatory response (TNFα and IL-6) in the brain. Similarly, the Evo mutant significantly increased TNFα production in the brain on day 2, which is mirrored in macrophages confronted with the Evo mutant, but not with the parental wild type. Whole genome sequencing of the Evo strain, genetic analyses, targeted gene disruption and a reverse microevolution experiment revealed a single nucleotide exchange in the chitin synthase-encoding CHS2 gene as the sole basis for this phenotypic alteration. A targeted CHS2 mutant with the same SNP showed similar phenotypes as the Evo strain under all experimental conditions tested. These results indicate that microevolutionary processes in host-simulative conditions can elicit adaptations of C. glabrata to distinct host niches and even lead to hypervirulent strains. Evolution is not limited to making new species emerge and others perish over the millennia. It is also a central force in shorter-term interactions between microbes and hosts. A good example can be found in fungi, which are an underestimated cause of human diseases. Some fungi exist as commensals, and have adapted well to life on human epithelia. But as facultative pathogens, they face a different, hostile environment. We tested the ability of C. glabrata, a pathogen closely related to baker's yeast, to adapt to macrophages. We found that by adaptation, it changed its growth type completely. This allowed the fungus to escape the phagocytes, and increased its virulence in a mouse model. Sequencing the complete genome revealed surprisingly few mutations. Further analyses allowed us to detect the single mutation responsible for the phenotype, and to recreate it in the parental strain. Our work shows that fungi can adapt to immune cells, and that this adaptation can lead to an increased virulence. Since commensals are continuously exposed to host cells, we suggest that this ability could lead to unexpected phenotype changes, including an increase in virulence potential.
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Affiliation(s)
- Sascha Brunke
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), Universitätsklinikum Jena, Jena, Germany
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Katja Seider
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Daniel Fischer
- Department of Microbial Pathogenicity Mechanisms, 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
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Nadja Jablonowski
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Anja Wartenberg
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
| | - Oliver Bader
- Institute for Medical Microbiology and German National Reference Centre for Systemic Mycoses, University Medical Centre Göttingen, Göttingen, Germany
| | - Adela Enache-Angoulvant
- APHP, Hôpital Bicêtre, Service de Bactériologie-Virologie-Parasitologie, Laboratoire de Parasitologie-Mycologie, Kremlin-Bicêtre, France
| | - Martin Schaller
- Department of Dermatology, Eberhard-Karls-University, Tübingen, Germany
| | - Christophe d'Enfert
- Institut Pasteur, Unité Biologie et Pathogénicité Fongiques, Département Génomes et Génétique, Paris, France
- INRA, USC2019, Paris, France
| | - Bernhard Hube
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), Universitätsklinikum Jena, Jena, Germany
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute Jena (HKI), Jena, Germany
- Friedrich Schiller University, Jena, Germany
- * E-mail:
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Bolotin-Fukuhara M, Fairhead C. Candida glabrata: a deadly companion? Yeast 2014; 31:279-88. [PMID: 24861573 DOI: 10.1002/yea.3019] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 04/16/2014] [Accepted: 05/06/2014] [Indexed: 11/08/2022] Open
Abstract
The yeast Candida glabrata has become a major fungal opportunistic pathogen of humans since the 1980s. Contrary to what its name suggests, it is much closer, phylogenetically, to the model yeast Saccharomyces cerevisiae than to the most prevalent human fungal pathogen, Candida albicans. Its similarity to S. cerevisiae fortunately extends to their amenability to molecular genetics methods. C. glabrata is now described as part of the Nakaseomyces clade, which includes two new pathogens and other environmental species. C. glabrata is likely a commensal species of the human digestive tract, but systemic infections of immunocompromised patients are often fatal. In addition to being the subject of active medical research, other studies on C. glabrata focus on fundamental aspects of evolution of yeast genomes and adaptation. For example, the genome of C. glabrata has undergone major gene and intron loss compared to S. cerevisiae. It is also an apparently asexual species, a feature that inevitably leads to questions about the species' evolutionary past, present and future. On-going research with this yeast continues to address various aspects of adaptation to the human host and mechanisms of evolution in the Saccharomycetaceae, major model organisms for biology.
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Candida glabrata intra-abdominal candidiasis is characterized by persistence within the peritoneal cavity and abscesses. Infect Immun 2014; 82:3015-22. [PMID: 24799629 DOI: 10.1128/iai.00062-14] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The pathogenesis of Candida glabrata infections is poorly understood. We studied the pathogenesis of intra-abdominal candidiasis (IAC) in mice that were infected intraperitoneally with C. glabrata and sterile feces. C. glabrata BG2 (5 × 10(8) CFU) caused a 100% mortality rate. Sublethal inocula of BG2 (1 × 10(8) or 1 × 10(7) CFU) caused peritonitis that progressed to abscesses. Three clinical C. glabrata strains (5 × 10(8) CFU) caused 80 to 100% mortality rates, while a fourth (strain 346) caused a 29% mortality rate. Following sublethal inocula (1 × 10(7) CFU), the intra-abscess burdens of virulent strain 356 were ∼1 log greater than those of strain 346. A C. glabrata Δplb1-2 mutant (phospholipase B genes disrupted) killed mice as well as BG2 did. When sublethal inocula were used, however, the Δplb1-2 mutant was associated with more rapid abscess resolution and lower intra-abscess burdens; these findings were reversed by PLB1 and PLB2 reinsertion. The Δplb1-2 mutant was also more susceptible than BG2 to killing by human neutrophils in vitro. BG2 and the Δplb1-2 mutant were indistinguishable during hematogenously disseminated candidiasis. C. albicans SC5314 was more virulent than C. glabrata BG2 during IAC, causing a 100% mortality rate following a challenge with 5 × 10(7) CFU. In contrast, a sublethal inoculum (1 × 10(7) CFU) of BG2 caused less neutrophil infiltration and greater burdens in peritoneal fluid than SC5314 did and abscesses that persisted longer and contained greater burdens. In conclusion, a mouse model of C. glabrata IAC mimics disease in humans and distinguishes the relative virulence of clinical and gene disruption strains. C. glabrata differed from C. albicans during IAC by being less lethal and eliciting dampened neutrophil responses but resulting in more persistent peritonitis and abscesses.
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Kasper L, Seider K, Gerwien F, Allert S, Brunke S, Schwarzmüller T, Ames L, Zubiria-Barrera C, Mansour MK, Becken U, Barz D, Vyas JM, Reiling N, Haas A, Haynes K, Kuchler K, Hube B. Identification of Candida glabrata genes involved in pH modulation and modification of the phagosomal environment in macrophages. PLoS One 2014; 9:e96015. [PMID: 24789333 PMCID: PMC4006850 DOI: 10.1371/journal.pone.0096015] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Accepted: 04/02/2014] [Indexed: 12/27/2022] Open
Abstract
Candida glabrata currently ranks as the second most frequent cause of invasive candidiasis. Our previous work has shown that C. glabrata is adapted to intracellular survival in macrophages and replicates within non-acidified late endosomal-stage phagosomes. In contrast, heat killed yeasts are found in acidified matured phagosomes. In the present study, we aimed at elucidating the processes leading to inhibition of phagosome acidification and maturation. We show that phagosomes containing viable C. glabrata cells do not fuse with pre-labeled lysosomes and possess low phagosomal hydrolase activity. Inhibition of acidification occurs independent of macrophage type (human/murine), differentiation (M1-/M2-type) or activation status (vitamin D3 stimulation). We observed no differential activation of macrophage MAPK or NFκB signaling cascades downstream of pattern recognition receptors after internalization of viable compared to heat killed yeasts, but Syk activation decayed faster in macrophages containing viable yeasts. Thus, delivery of viable yeasts to non-matured phagosomes is likely not triggered by initial recognition events via MAPK or NFκB signaling, but Syk activation may be involved. Although V-ATPase is abundant in C. glabrata phagosomes, the influence of this proton pump on intracellular survival is low since blocking V-ATPase activity with bafilomycin A1 has no influence on fungal viability. Active pH modulation is one possible fungal strategy to change phagosome pH. In fact, C. glabrata is able to alkalinize its extracellular environment, when growing on amino acids as the sole carbon source in vitro. By screening a C. glabrata mutant library we identified genes important for environmental alkalinization that were further tested for their impact on phagosome pH. We found that the lack of fungal mannosyltransferases resulted in severely reduced alkalinization in vitro and in the delivery of C. glabrata to acidified phagosomes. Therefore, protein mannosylation may play a key role in alterations of phagosomal properties caused by C. glabrata.
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Affiliation(s)
- Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Katja Seider
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Franziska Gerwien
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Stefanie Allert
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
| | - Tobias Schwarzmüller
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University, Vienna, Austria
| | - Lauren Ames
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Cristina Zubiria-Barrera
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
| | - Michael K. Mansour
- Massachusetts General Hospital, Department of Medicine, Division of Infectious Disease, Boston, Massachusetts, United States of America
| | | | - Dagmar Barz
- Institute for Transfusion Medicine, University Hospital, Jena, Germany
| | - Jatin M. Vyas
- Massachusetts General Hospital, Department of Medicine, Division of Infectious Disease, Boston, Massachusetts, United States of America
| | - Norbert Reiling
- Division of Microbial Interface Biology, Research Center Borstel, Leibniz Center for Medicine and Biosciences, Borstel, Germany
| | - Albert Haas
- Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Ken Haynes
- College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Karl Kuchler
- Department of Medical Biochemistry, Max F. Perutz Laboratories, Medical University, Vienna, Austria
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology – Hans Knoell Institute, Jena, Germany
- Integrated Research and Treatment Center, Sepsis und Sepsisfolgen, Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
- Friedrich Schiller University, Jena, Germany
- * E-mail:
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14
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Immune evasion, stress resistance, and efficient nutrient acquisition are crucial for intracellular survival of Candida glabrata within macrophages. EUKARYOTIC CELL 2013; 13:170-83. [PMID: 24363366 DOI: 10.1128/ec.00262-13] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Candida glabrata is both a human fungal commensal and an opportunistic pathogen which can withstand activities of the immune system. For example, C. glabrata can survive phagocytosis and replicates within macrophages. However, the mechanisms underlying intracellular survival remain unclear. In this work, we used a functional genomic approach to identify C. glabrata determinants necessary for survival within human monocyte-derived macrophages by screening a set of 433 deletion mutants. We identified 23 genes which are required to resist killing by macrophages. Based on homologies to Saccharomyces cerevisiae orthologs, these genes are putatively involved in cell wall biosynthesis, calcium homeostasis, nutritional and stress response, protein glycosylation, or iron homeostasis. Mutants were further characterized using a series of in vitro assays to elucidate the genes' functions in survival. We investigated different parameters of C. glabrata-phagocyte interactions: uptake by macrophages, replication within macrophages, phagosomal pH, and recognition of mutant cells by macrophages as indicated by production of reactive oxygen species and tumor necrosis factor alpha (TNF-α). We further studied the cell surface integrity of mutant cells, their ability to grow under nutrient-limited conditions, and their susceptibility to stress conditions mirroring the harsh environment inside a phagosome. Additionally, resistance to killing by neutrophils was analyzed. Our data support the view that immune evasion is a key aspect of C. glabrata virulence and that increased immune recognition causes increased antifungal activities by macrophages. Furthermore, stress resistance and efficient nutrient acquisition, in particular, iron uptake, are crucial for intraphagosomal survival of C. glabrata.
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15
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Thriving within the host: Candida spp. interactions with phagocytic cells. Med Microbiol Immunol 2013; 202:183-95. [DOI: 10.1007/s00430-013-0288-z] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 01/10/2013] [Indexed: 01/04/2023]
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16
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Seider K, Brunke S, Schild L, Jablonowski N, Wilson D, Majer O, Barz D, Haas A, Kuchler K, Schaller M, Hube B. The facultative intracellular pathogen Candida glabrata subverts macrophage cytokine production and phagolysosome maturation. THE JOURNAL OF IMMUNOLOGY 2011; 187:3072-86. [PMID: 21849684 DOI: 10.4049/jimmunol.1003730] [Citation(s) in RCA: 160] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Although Candida glabrata is an important human pathogenic yeast, its pathogenicity mechanisms are largely unknown. Immune evasion strategies seem to play key roles during infection, since very little inflammation is observed in mouse models. Furthermore, C. glabrata multiplies intracellularly after engulfment by macrophages. In this study, we sought to identify the strategies that enable C. glabrata to survive phagosome biogenesis and antimicrobial activities within human monocyte-derived macrophages. We show that, despite significant intracellular proliferation, macrophage damage or apoptosis was not apparent, and production of reactive oxygen species was inhibited. Additionally, with the exception of GM-CSF, levels of pro- and anti-inflammatory cytokines were only marginally increased. We demonstrate that adhesion to and internalization by macrophages occur within minutes, and recruitment of endosomal early endosomal Ag 1 and lysosomal-associated membrane protein 1 indicates phagosome maturation. However, phagosomes containing viable C. glabrata, but not heat-killed yeasts, failed to recruit cathepsin D and were only weakly acidified. This inhibition of acidification did not require fungal viability, but it had a heat-sensitive surface attribute. Therefore, C. glabrata modifies the phagosome into a nonacidified environment and multiplies until the host cells finally lyse and release the fungi. Our results suggest persistence of C. glabrata within macrophages as a possible immune evasion strategy.
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Affiliation(s)
- Katja Seider
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knoell Institute, 07745 Jena, Germany
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Newman SL, Gootee L, Brunner G, Deepe GS. Chloroquine induces human macrophage killing of Histoplasma capsulatum by limiting the availability of intracellular iron and is therapeutic in a murine model of histoplasmosis. J Clin Invest 1994; 93:1422-9. [PMID: 8163646 PMCID: PMC294155 DOI: 10.1172/jci117119] [Citation(s) in RCA: 107] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
We investigated the role of intracellular iron on the capacity of Histoplasma capsulatum (Hc) yeasts to multiply within human macrophages (Mphi). Coculture of Hc-infected Mphi with the iron chelator deferoxamine suppressed the growth of yeasts in a concentration-dependent manner. The effect of deferoxamine was reversed by iron-saturated transferrin (holotransferrin) but not by iron-free transferrin (apotransferrin). Chloroquine, which prevents release of iron from transferrin by raising endocytic and lysosomal pH, induced human Mphi to kill Hc. The effect of chloroquine was reversed by iron nitriloacetate, an iron compound that is soluble at neutral to alkaline pH, but not by holotransferrin, which releases iron only in an acidic environment. Chloroquine (40-120 mg/kg) given intraperitoneally for 6 d to Hc-infected C57BL/6 mice significantly reduced the growth of Hc in a dose-dependent manner. At 120 mg/kg there was a 17- and 15-fold reduction (P < 0.01) in CFU in spleens and livers, respectively. The therapeutic effect of chloroquine also correlated with the length of treatment. As little as 2 d of chloroquine therapy (120 mg/kg), when started at day 5 after infection, reduced CFU in the spleen by 50%. Treatment with chloroquine for 10 d after a lethal inoculum of Hc protected six of nine mice; all control mice were dead by day 11 (P = 0.009). This study demonstrates that: (a) iron is of critical importance to the survival and multiplication of Hc yeasts in human Mphi; (b) in vitro, chloroquine induces Mphi killing of Hc yeasts by restricting the availability of intracellular iron; and (c) in vivo, chloroquine significantly reduces the number of organisms in the spleens and livers of Hc-infected mice and can protect mice from a lethal inoculum of Hc yeasts. Thus, chloroquine may be effective in the treatment of active histoplasmosis and also may be useful in preventing relapse of histoplasmosis in patients with acquired immunodeficiency syndromes.
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Affiliation(s)
- S L Newman
- Department of Medicine, University of Cincinnati College of Medicine, Ohio 45267
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Abstract
Rilopirox, 6-[[p-chlorophenoxy)phenoxy]methyl]-1hydroxy-4-methyl-2(1H)-pyrido ne, is a new fungicidal antimycotic with very low water solubility. It was designed to meet the demand for an intravaginal antifungal with a long skin retention time and a strong killing effect on pathogenic yeasts. In addition, it inhibits all common fungal pathogens in the range 0.98 to 15.6 micrograms/ml. Fungicidal rates vis-à-vis Trichophyton mentagrophytes and Candida albicans under proliferative and non-proliferative conditions are higher than those achieved with common azole and allylamine antifungals. Rilopirox is affected by Fe3+ ions and high concentrations of human serum owing to its chelating activity. The peptone source is of utmost importance to the inhibitory activity of rilopirox whereas the pH value seems to be unimportant so long as it is within the range 5-8.5. Rilopirox appears to meet the demand for an intravaginal antifungal as a result of its very low water solubility of 50 ng/ml and its immediate fungicidal action even under non-proliferative conditions.
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Affiliation(s)
- W Raether
- Hoechst AG, Frankfurt/Main, Germany FR
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