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Li X, Paccoud O, Chan KH, Yuen KY, Manchon R, Lanternier F, Slavin MA, van de Veerdonk FL, Bicanic T, Lortholary O. Cryptococcosis Associated With Biologic Therapy: A Narrative Review. Open Forum Infect Dis 2024; 11:ofae316. [PMID: 38947739 PMCID: PMC11212009 DOI: 10.1093/ofid/ofae316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2024] [Accepted: 06/17/2024] [Indexed: 07/02/2024] Open
Abstract
Cryptococcus is an opportunistic fungal pathogen that can cause disseminated infection with predominant central nervous system involvement in patients with compromised immunity. Biologics are increasingly used in the treatment of neoplasms and autoimmune/inflammatory conditions and the prevention of transplant rejection, which may affect human defense mechanisms against cryptococcosis. In this review, we comprehensively investigate the association between cryptococcosis and various biologics, highlighting their risks of infection, clinical manifestations, and clinical outcomes. Clinicians should remain vigilant for the risk of cryptococcosis in patients receiving biologics that affect the Th1/macrophage activation pathways, such as tumor necrosis factor α antagonists, Bruton tyrosine kinase inhibitors, fingolimod, JAK/STAT inhibitors (Janus kinase/signal transducer and activator of transcription), and monoclonal antibody against CD52. Other risk factors-such as age, underlying condition, and concurrent immunosuppressants, especially corticosteroids-should also be taken into account during risk stratification.
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Affiliation(s)
- Xin Li
- Department of Infectious Diseases and Tropical Medicine, Université Paris Cité, Necker-Enfants Malades University Hospital, Assistance Publique–Hôpitaux de Paris, IHU Imagine, Paris, France
- Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Olivier Paccoud
- Department of Infectious Diseases and Tropical Medicine, Université Paris Cité, Necker-Enfants Malades University Hospital, Assistance Publique–Hôpitaux de Paris, IHU Imagine, Paris, France
| | - Koon-Ho Chan
- Department of Medicine, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Kwok-Yung Yuen
- Department of Microbiology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Pokfulam, Hong Kong SAR, China
| | - Romain Manchon
- Department of Infectious Diseases and Tropical Medicine, Université Paris Cité, Necker-Enfants Malades University Hospital, Assistance Publique–Hôpitaux de Paris, IHU Imagine, Paris, France
| | - Fanny Lanternier
- Department of Infectious Diseases and Tropical Medicine, Université Paris Cité, Necker-Enfants Malades University Hospital, Assistance Publique–Hôpitaux de Paris, IHU Imagine, Paris, France
- Institut Pasteur, National Reference Center for Invasive Mycoses and Antifungals, Mycology Translational Research Group, Mycology Department, Université Paris Cité, Paris, France
| | - Monica A Slavin
- Department of Infectious Diseases, Peter MacCallum Cancer Centre, Melbourne, Australia
- Sir Peter MacCallum Department of Oncology, University of Melbourne, Melbourne, Australia
- Victorian Infectious Diseases Service, Royal Melbourne Hospital, Melbourne, Australia
| | - Frank L van de Veerdonk
- Department of Internal Medicine, Radboud Center for Infectious Diseases, Radboudumc, Nijmegen, the Netherlands
| | - Tihana Bicanic
- Institute of Infection and Immunity, St George's University of London, London, UK
| | - Olivier Lortholary
- Department of Infectious Diseases and Tropical Medicine, Université Paris Cité, Necker-Enfants Malades University Hospital, Assistance Publique–Hôpitaux de Paris, IHU Imagine, Paris, France
- Institut Pasteur, National Reference Center for Invasive Mycoses and Antifungals, Mycology Translational Research Group, Mycology Department, Université Paris Cité, Paris, France
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Rossi SA, García-Barbazán I, Chamorro-Herrero I, Taborda CP, Zaragoza Ó, Zambrano A. Use of 2D minilungs from human embryonic stem cells to study the interaction of Cryptococcus neoformans with the respiratory tract. Microbes Infect 2024; 26:105260. [PMID: 37981028 DOI: 10.1016/j.micinf.2023.105260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 11/09/2023] [Accepted: 11/16/2023] [Indexed: 11/21/2023]
Abstract
Organoids can meet the needs between the use of cell culture and in vivo work, bringing together aspects of multicellular tissues, providing a more similar in vitro system for the study of various components, including host-interactions with pathogens and drug response. Organoids are structures that resemble organs in vivo, originating from pluripotent stem cells (PSCs) or adult stem cells (ASCs). There is great interest in deepening the understanding of the use of this technology to produce information about fungal infections and their treatments. This work aims the use 2D human lung organoid derived from human embryonic stem cells (hESCs), to investigate Cryptococcus neoformans-host interactions. C. neoformans is an opportunistic fungus acquired by inhalation that causes systemic mycosis mainly in immunocompromised individuals. Our work highlights the suitability of human minilungs for the study of C. neoformans infection (adhesion, invasion and replication), the interaction with the surfactant and induction of the host's alveolar pro-inflammatory response.
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Affiliation(s)
- Suélen Andreia Rossi
- Biotechnology of Stem Cells and Organoids, Chronic Disease Program, Carlos III Health Institute, Madrid, Spain; Department of Microbiology, Biomedical Sciences Institute, University of São Paulo (USP), São Paulo, Brazil; Mycology Reference Laboratory, National Centre for Microbiology, Carlos III Health Institute, Madrid, Spain
| | - Irene García-Barbazán
- Mycology Reference Laboratory, National Centre for Microbiology, Carlos III Health Institute, Madrid, Spain
| | - Irene Chamorro-Herrero
- Biotechnology of Stem Cells and Organoids, Chronic Disease Program, Carlos III Health Institute, Madrid, Spain
| | - Carlos Pelleschi Taborda
- Department of Microbiology, Biomedical Sciences Institute, University of São Paulo (USP), São Paulo, Brazil; Tropical Medicine Institute, Department of Dermatology, Faculty of Medicine, University of São Paulo, São Paulo 05403-000, Brazil.
| | - Óscar Zaragoza
- Mycology Reference Laboratory, National Centre for Microbiology, Carlos III Health Institute, Madrid, Spain; Center for Biomedical Research in Network in Infectious Diseases (CIBERINFEC, Carlos III Health Institute, CB21/13/00105), Madrid, Spain.
| | - Alberto Zambrano
- Biotechnology of Stem Cells and Organoids, Chronic Disease Program, Carlos III Health Institute, Madrid, Spain.
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Crossen AJ, Ward RA, Reedy JL, Surve MV, Klein BS, Rajagopal J, Vyas JM. Human Airway Epithelium Responses to Invasive Fungal Infections: A Critical Partner in Innate Immunity. J Fungi (Basel) 2022; 9:40. [PMID: 36675861 PMCID: PMC9862202 DOI: 10.3390/jof9010040] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/09/2022] [Accepted: 12/26/2022] [Indexed: 12/29/2022] Open
Abstract
The lung epithelial lining serves as the primary barrier to inhaled environmental toxins, allergens, and invading pathogens. Pulmonary fungal infections are devastating and carry high mortality rates, particularly in those with compromised immune systems. While opportunistic fungi infect primarily immunocompromised individuals, endemic fungi cause disease in immune competent and compromised individuals. Unfortunately, in the case of inhaled fungal pathogens, the airway epithelial host response is vastly understudied. Furthering our lack of understanding, very few studies utilize primary human models displaying pseudostratified layers of various epithelial cell types at air-liquid interface. In this review, we focus on the diversity of the human airway epithelium and discuss the advantages and disadvantages of oncological cell lines, immortalized epithelial cells, and primary epithelial cell models. Additionally, the responses by human respiratory epithelial cells to invading fungal pathogens will be explored. Future investigations leveraging current human in vitro model systems will enable identification of the critical pathways that will inform the development of novel vaccines and therapeutics for pulmonary fungal infections.
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Affiliation(s)
- Arianne J. Crossen
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Rebecca A. Ward
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Jennifer L. Reedy
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Manalee V. Surve
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
| | - Bruce S. Klein
- Department of Pediatrics, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53706, USA
- Department of Medical Microbiology and Immunology, School of Medicine and Public Health, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Jayaraj Rajagopal
- Center for Regenerative Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114, USA
- Harvard Stem Cell Institute, Cambridge, MA 02138, USA
- Klarman Cell Observatory, Broad Institute of Massachusetts Institute of Technology and Harvard, Cambridge, MA 02142, USA
| | - Jatin M. Vyas
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA 02114, USA
- Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
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Abstract
Cryptococcosis is a disease caused by the pathogenic fungi Cryptococcus neoformans and Cryptococcus gattii, both environmental fungi that cause severe pneumonia and may even lead to cryptococcal meningoencephalitis. Although C. neoformans affects more fragile individuals, such as immunocompromised hosts through opportunistic infections, C. gattii causes a serious indiscriminate primary infection in immunocompetent individuals. Typically seen in tropical and subtropical environments, C. gattii has increased its endemic area over recent years, largely due to climatic factors that favor contagion in warmer climates. It is important to point out that not only C. gattii, but the Cryptococcus species complex produces a polysaccharidic capsule with immunomodulatory properties, enabling the pathogenic species of Cryptococccus to subvert the host immune response during the establishment of cryptococcosis, facilitating its dissemination in the infected organism. C. gattii causes a more severe and difficult-to-treat infection, with few antifungals eliciting an effective response during chronic treatment. Much of the immunopathology of this cryptococcosis is still poorly understood, with most studies focusing on cryptococcosis caused by the species C. neoformans. C. gattii became more important in the epidemiological scenario with the outbreaks in the Pacific Northwest of the United States, which resulted in phylogenetic studies of the virulent variant responsible for the severe infection in the region. Since then, the study of cryptococcosis caused by C. gattii has helped researchers understand the immunopathological aspects of different variants of this pathogen.
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Last A, Maurer M, S. Mosig A, S. Gresnigt M, Hube B. In vitro infection models to study fungal-host interactions. FEMS Microbiol Rev 2021; 45:fuab005. [PMID: 33524102 PMCID: PMC8498566 DOI: 10.1093/femsre/fuab005] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2020] [Accepted: 01/14/2021] [Indexed: 12/14/2022] Open
Abstract
Fungal infections (mycoses) affect over a billion people per year. Approximately, two million of these infections are life-threatening, especially for patients with a compromised immune system. Fungi of the genera Aspergillus, Candida, Histoplasma and Cryptococcus are opportunistic pathogens that contribute to a substantial number of mycoses. To optimize the diagnosis and treatment of mycoses, we need to understand the complex fungal-host interplay during pathogenesis, the fungal attributes causing virulence and how the host resists infection via immunological defenses. In vitro models can be used to mimic fungal infections of various tissues and organs and the corresponding immune responses at near-physiological conditions. Furthermore, models can include fungal interactions with the host-microbiota to mimic the in vivo situation on skin and mucosal surfaces. This article reviews currently used in vitro models of fungal infections ranging from cell monolayers to microfluidic 3D organ-on-chip (OOC) platforms. We also discuss how OOC models can expand the toolbox for investigating interactions of fungi and their human hosts in the future.
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Affiliation(s)
- Antonia Last
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knoell Institute, Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Michelle Maurer
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Institute of Biochemistry II, Jena University Hospital, Nonnenplan 2,07743, Jena, Germany
| | - Alexander S. Mosig
- Center for Sepsis Control and Care (CSCC), Jena University Hospital, Am Klinikum 1, 07747, Jena, Germany
- Institute of Biochemistry II, Jena University Hospital, Nonnenplan 2,07743, Jena, Germany
| | - Mark S. Gresnigt
- Junior Research Group Adaptive Pathogenicity Strategies, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knoell Institute, Beutenbergstrasse 11a, 07745, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology—Hans Knoell Institute, Beutenbergstrasse 11a, 07745, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Neugasse 24, 07743, Jena, Germany
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Strickland AB, Shi M. Mechanisms of fungal dissemination. Cell Mol Life Sci 2021; 78:3219-3238. [PMID: 33449153 PMCID: PMC8044058 DOI: 10.1007/s00018-020-03736-z] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 11/23/2020] [Accepted: 12/08/2020] [Indexed: 12/13/2022]
Abstract
Fungal infections are an increasing threat to global public health. There are more than six million fungal species worldwide, but less than 1% are known to infect humans. Most of these fungal infections are superficial, affecting the hair, skin and nails, but some species are capable of causing life-threatening diseases. The most common of these include Cryptococcus neoformans, Aspergillus fumigatus and Candida albicans. These fungi are typically innocuous and even constitute a part of the human microbiome, but if these pathogens disseminate throughout the body, they can cause fatal infections which account for more than one million deaths worldwide each year. Thus, systemic dissemination of fungi is a critical step in the development of these deadly infections. In this review, we discuss our current understanding of how fungi disseminate from the initial infection sites to the bloodstream, how immune cells eliminate fungi from circulation and how fungi leave the blood and enter distant organs, highlighting some recent advances and offering some perspectives on future directions.
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Affiliation(s)
- Ashley B Strickland
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, USA.
| | - Meiqing Shi
- Division of Immunology, Virginia-Maryland College of Veterinary Medicine and Maryland Pathogen Research Institute, University of Maryland, College Park, MD, USA.
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7
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Gu Z. An improved staining method of cell cycle analysis with Sybr Green I for fungi: Cryptococcus neoformans and Saccharomyces cerevisiae. Cell Cycle 2021; 20:271-282. [PMID: 33463377 PMCID: PMC7889188 DOI: 10.1080/15384101.2020.1870334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 12/13/2020] [Accepted: 12/28/2020] [Indexed: 10/22/2022] Open
Abstract
Cryptococcus neoformans is a pathogenic fungus which causes millions of deaths and infections, especially threatening immunocompromised individuals. During the development of new drugs, the ubiquitination has been found to play an important role in the regulation of the virulence and cell cycle of this fungus. Based on this mechanism, ubiquitination-related mutant strains exhibiting cell cycle arrest have been established for drug development for the fungus. However, flow cytometry detection of the cell cycle in fungi is generally difficult because the thick cell wall and capsule of fungi generally contribute to a nonspecific signal of cytometry. In this study, an improved method, derived from Saccharomyces cerevisiae assays, is developed to specifically stain C. neoformans, in whose cell cycle the G1 and G2 peaks are separated enough to be allowed for cell cycle analysis. As a result, the improved method facilitates the detection of the alterations in the cell cycle of C. neoformans with a mutation that results in cell cycle arrest, which distinctly delays the cell division of C. neoformans. Thus, the improved method reported here provides detailed technical information regarding assays on C. neoformans and, more importantly, offers a solution for assessing the cell cycle in other fungi in the future. Abbreviation: PI: propidium iodide.
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Affiliation(s)
- Zhongkai Gu
- Institutes of Biomedical Sciences, Fudan University, Shanghai, People’s Republic of China
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8
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Sun Z, Ji N, Jiang J, Tao Y, Zhang E, Yang X, Wang Z, Chen Z, Huang M, Zhang M. Fine Particulate Matter (PM 2. 5) Promotes CD146 Expression in Alveolar Epithelial Cells and Cryptococcus neoformans Pulmonary Infection. Front Microbiol 2021; 11:525976. [PMID: 33537006 PMCID: PMC7848894 DOI: 10.3389/fmicb.2020.525976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Accepted: 12/14/2020] [Indexed: 11/13/2022] Open
Abstract
Air pollution is a leading cause of increasing infectious lung diseases. Pulmonary cryptococcosis is a fatal fungal pneumonia in acquired immunodeficiency syndrome patients. In some cases, the pathogen Cryptococcus neoformans also develops dormant nodules in immunocompetent individuals. In the present study, we demonstrated that fine particulate matter (PM2.5) increased CD146 expression in alveolar epithelial cells and promoted C. neoformans pulmonary infection. Aryl hydrocarbon receptor (AhR) signaling was required for increased expression of CD146 in epithelial cells treated with PM2.5. In a murine model of pulmonary infection, PM2.5 promoted fungal infection, and CD146 deficiency decreased the fugal burden of C. neoformans. Our study may highlight the importance of air pollution to lung mycosis and CD146 as a target for preventing infectious lung diseases.
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Affiliation(s)
- Zhixiao Sun
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Ningfei Ji
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Jingxian Jiang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yuan Tao
- NHC Key Laboratory of Antibody Technique, Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Enrui Zhang
- NHC Key Laboratory of Antibody Technique, Department of Immunology, Nanjing Medical University, Nanjing, China
| | - Xiaofan Yang
- Laboratory Center for Basic Medical Sciences, Nanjing Medical University, Nanjing, China
| | - Zhengxia Wang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhongqi Chen
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Mao Huang
- Department of Respiratory and Critical Care Medicine, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Mingshun Zhang
- NHC Key Laboratory of Antibody Technique, Department of Immunology, Nanjing Medical University, Nanjing, China
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Freitas MS, Pessoni AM, Coelho C, Bonato VLD, Rodrigues ML, Casadevall A, Almeida F. Interactions of Extracellular Vesicles from Pathogenic Fungi with Innate Leukocytes. Curr Top Microbiol Immunol 2021; 432:89-120. [DOI: 10.1007/978-3-030-83391-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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10
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Normile TG, Bryan AM, Del Poeta M. Animal Models of Cryptococcus neoformans in Identifying Immune Parameters Associated With Primary Infection and Reactivation of Latent Infection. Front Immunol 2020; 11:581750. [PMID: 33042164 PMCID: PMC7522366 DOI: 10.3389/fimmu.2020.581750] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 08/12/2020] [Indexed: 12/13/2022] Open
Abstract
Cryptococcus species are environmental fungal pathogens and the causative agents of cryptococcosis. Infection occurs upon inhalation of infectious particles, which proliferate in the lung causing a primary infection. From this primary lung infection, fungal cells can eventually disseminate to other organs, particularly the brain, causing lethal meningoencephalitis. However, in most cases, the primary infection resolves with the formation of a lung granuloma. Upon severe immunodeficiency, dormant cryptococcal cells will start proliferating in the lung granuloma and eventually will disseminate to the brain. Many investigators have sought to study the protective host immune response to this pathogen in search of host parameters that keep the proliferation of cryptococcal cells under control. The majority of the work assimilates research carried out using the primary infection animal model, mainly because a reactivation model has been available only very recently. This review will focus on anti-cryptococcal immunity in both the primary and reactivation models. An understanding of the differences in host immunity between the primary and reactivation models will help to define the key host parameters that control the infections and are important for the research and development of new therapeutic and vaccine strategies against cryptococcosis.
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Affiliation(s)
- Tyler G Normile
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States
| | - Arielle M Bryan
- Ingenious Targeting Laboratory Incorporated, Ronkonkoma, NY, United States
| | - Maurizio Del Poeta
- Department of Microbiology and Immunology, Stony Brook University, Stony Brook, NY, United States.,Division of Infectious Diseases, School of Medicine, Stony Brook University, Stony Brook, NY, United States.,Veterans Administration Medical Center, Northport, NY, United States
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11
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A glucuronoxylomannan-like glycan produced by Trichosporon mucoides. Fungal Genet Biol 2018; 121:46-55. [PMID: 30268928 DOI: 10.1016/j.fgb.2018.09.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 08/27/2018] [Accepted: 09/26/2018] [Indexed: 01/06/2023]
Abstract
Trichosporon asahii shares with Cryptococcus species the ability to produce glucuronoxylomannan (GXM), an immunomodulatory fungal polysaccharide. The ability of other opportunistic species of Trichosporon to produce GXM-like polysaccharides is unknown. In this study, we observed that T. mucoides was less pathogenic than T. asahii in an infection model of Galleria mellonella and asked whether this difference was related to the characteristics of GXM-like molecules. Compositional analysis of samples obtained from both pathogens indicated that the components of GXM (mannose, xylose and glucuronic acid) were, in fact, detected in T. mucoides and T. asahii glycans. The identification of the T. mucoides glycan as a GXM-like molecule was confirmed by its reactivity with a monoclonal antibody raised to cryptococcal GXM and incorporation of the glycan into the cell surface of an acapsular mutant of C. neoformans. T. mucoides and T. asahii glycans differed in molecular dimensions. The antibody to cryptococcal GXM recognized T. mucoides yeast forms less efficiently than T. asahii cells. Experiments with animal cells revealed that the T. mucoides glycan manifested antiphagocytic properties. Comparative phagocytosis assays revealed that T. mucoides and T. asahii were similarly recognized by macrophages. However, fungal association with the phagocytes did not depend on the typical receptors of cryptococcal GXM, as concluded from assays using macrophages obtained from Tlr2-/- and Cd14-/- knockout mice. These results add T. mucoides to the list of fungal pathogens producing GXM-like glycans, but also indicate a high functional diversity of this major fungal immunogen.
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12
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Mechanisms of Pulmonary Escape and Dissemination by Cryptococcus neoformans. J Fungi (Basel) 2018; 4:jof4010025. [PMID: 29463005 PMCID: PMC5872328 DOI: 10.3390/jof4010025] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 02/09/2018] [Accepted: 02/16/2018] [Indexed: 12/15/2022] Open
Abstract
Cryptococcus neoformans is a common environmental saprophyte and human fungal pathogen that primarily causes disease in immunocompromised individuals. Similar to many environmentally acquired human fungal pathogens, C. neoformans initiates infection in the lungs. However, the main driver of mortality is invasive cryptococcosis leading to fungal meningitis. After C. neoformans gains a foothold in the lungs, a critical early step in invasion is transversal of the respiratory epithelium. In this review, we summarize current knowledge relating to pulmonary escape. We focus on fungal factors that allow C. neoformans to disseminate from the lungs via intracellular and extracellular routes.
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13
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Taylor-Smith LM. Cryptococcus-Epithelial Interactions. J Fungi (Basel) 2017; 3:jof3040053. [PMID: 29371569 PMCID: PMC5753155 DOI: 10.3390/jof3040053] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 09/28/2017] [Accepted: 09/30/2017] [Indexed: 12/12/2022] Open
Abstract
The fungal pathogen, Cryptococcus neoformans, causes devastating levels of morbidity and mortality. Infections with this fungus tend to be predominantly in immunocompromised individuals, such as those with HIV. Infections initiate with inhalation of cryptococcal cells and entry of the pathogen into the lungs. The bronchial epithelial cells of the upper airway and the alveolar epithelial cells of the lower airway are likely to be the first host cells that Cryptococcus engage with. Thus the interaction of cryptococci and the respiratory epithelia will be the focus of this review. C. neoformans has been shown to adhere to respiratory epithelial cells, although if the role of the capsule is in aiding or hindering this adhesion is debatable. The epithelia are also able to react to cryptococci with the release of cytokines and chemokines to start the immune response to this invading pathogen. The activity of surfactant components that line this mucosal barrier towards Cryptococcus and the metabolic and transcriptional reaction of cryptococci when encountering epithelial cells will also be discussed.
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Affiliation(s)
- Leanne M Taylor-Smith
- Institute of Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, West Midlands, UK.
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14
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Heyen L, Müller U, Siegemund S, Schulze B, Protschka M, Alber G, Piehler D. Lung epithelium is the major source of IL-33 and is regulated by IL-33-dependent and IL-33-independent mechanisms in pulmonary cryptococcosis. Pathog Dis 2016; 74:ftw086. [DOI: 10.1093/femspd/ftw086] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/01/2016] [Indexed: 01/08/2023] Open
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15
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Vargas G, Rocha JDB, Oliveira DL, Albuquerque PC, Frases S, Santos SS, Nosanchuk JD, Gomes AMO, Medeiros LCAS, Miranda K, Sobreira TJP, Nakayasu ES, Arigi EA, Casadevall A, Guimaraes AJ, Rodrigues ML, Freire-de-Lima CG, Almeida IC, Nimrichter L. Compositional and immunobiological analyses of extracellular vesicles released by Candida albicans. Cell Microbiol 2014; 17:389-407. [PMID: 25287304 DOI: 10.1111/cmi.12374] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Revised: 09/08/2014] [Accepted: 09/22/2014] [Indexed: 12/14/2022]
Abstract
The release of extracellular vesicles (EV) by fungal organisms is considered an alternative transport mechanism to trans-cell wall passage of macromolecules. Previous studies have revealed the presence of EV in culture supernatants from fungal pathogens, such as Cryptococcus neoformans, Histoplasma capsulatum, Paracoccidioides brasiliensis, Sporothrix schenckii, Malassezia sympodialis and Candida albicans. Here we investigated the size, composition, kinetics of internalization by bone marrow-derived murine macrophages (MO) and dendritic cells (DC), and the immunomodulatory activity of C. albicans EV. We also evaluated the impact of EV on fungal virulence using the Galleria mellonella larvae model. By transmission electron microscopy and dynamic light scattering, we identified two populations ranging from 50 to 100 nm and 350 to 850 nm. Two predominant seroreactive proteins (27 kDa and 37 kDa) and a group of polydispersed mannoproteins were observed in EV by immunoblotting analysis. Proteomic analysis of C. albicans EV revealed proteins related to pathogenesis, cell organization, carbohydrate and lipid metabolism, response to stress, and several other functions. The major lipids detected by thin-layer chromatography were ergosterol, lanosterol and glucosylceramide. Short exposure of MO to EV resulted in internalization of these vesicles and production of nitric oxide, interleukin (IL)-12, transforming growth factor-beta (TGF-β) and IL-10. Similarly, EV-treated DC produced IL-12p40, IL-10 and tumour necrosis factor-alpha. In addition, EV treatment induced the up-regulation of CD86 and major histocompatibility complex class-II (MHC-II). Inoculation of G. mellonella larvae with EV followed by challenge with C. albicans reduced the number of recovered viable yeasts in comparison with infected larvae control. Taken together, our results demonstrate that C. albicans EV were immunologically active and could potentially interfere with the host responses in the setting of invasive candidiasis.
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Affiliation(s)
- Gabriele Vargas
- Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil
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16
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Albuquerque PC, Fonseca FL, Dutra FF, Bozza MT, Frases S, Casadevall A, Rodrigues ML. Cryptococcus neoformans glucuronoxylomannan fractions of different molecular masses are functionally distinct. Future Microbiol 2014; 9:147-61. [PMID: 24571070 DOI: 10.2217/fmb.13.163] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
AIMS Glucuronoxylomannan (GXM) is the major polysaccharide component of Cryptococcus neoformans. We evaluated in this study whether GXM fractions of different molecular masses were functionally distinct. MATERIALS & METHODS GXM samples isolated from C. neoformans cultures were fractionated to generate polysaccharide preparations differing in molecular mass. These fractions were used in experiments focused on the association of GXM with cell wall components of C. neoformans, as well as on the interaction of the polysaccharide with host cells. RESULTS & CONCLUSION GXM fractions of variable molecular masses bound to the surface of a C. neoformans acapsular mutant in a punctate pattern that is in contrast to the usual annular pattern of surface coating observed when GXM samples containing the full molecular mass range were used. The polysaccharide samples were also significantly different in their ability to stimulate cytokine production by host cells. Our findings indicate that GXM fractions are functionally distinct depending on their mass.
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Affiliation(s)
- Priscila C Albuquerque
- Centro de Desenvolvimento Tecnológico em Saúde, CTDS-Fiocruz. Avenida Brasil 4036, Prédio da Expansão, 8o andar, Sala 814, Rio de Janeiro, RJ, 21040-361, Brazil
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17
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Abstract
To infect the host and cause disease, many medically important fungi invade normally nonphagocytic host cells, such as endothelial cells and epithelial cells. Host cell invasion is a two-step process consisting of adherence followed by invasion. There are two general mechanisms of host cell invasion, induced endocytosis and active penetration. Furthermore, fungi can traverse epithelial or endothelial cell barriers either by proteolytic degradation of intercellular tight junctions or via a Trojan horse mechanism in which they are transported by leukocytes. Although these mechanisms of host cell invasion have been best studied using Candida albicans and Cryptococcus neoformans, it is probable that other invasive fungi also use one or more of these mechanisms to invade host cells. Identification of these invasion mechanisms holds promise to facilitate the development of new approaches to inhibit fungal invasion and thereby prevent disease.
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Affiliation(s)
- Donald C Sheppard
- Departments of Microbiology and Immunology and Medicine, McGill University, Montreal, Quebec H3A 2B4, Canada
| | - Scott G Filler
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, California 90502 David Geffen School of Medicine at UCLA, Los Angeles, California 90025
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18
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Silveira CP, Piffer AC, Kmetzsch L, Fonseca FL, Soares DA, Staats CC, Rodrigues ML, Schrank A, Vainstein MH. The heat shock protein (Hsp) 70 of Cryptococcus neoformans is associated with the fungal cell surface and influences the interaction between yeast and host cells. Fungal Genet Biol 2013; 60:53-63. [PMID: 23954835 DOI: 10.1016/j.fgb.2013.08.005] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 08/01/2013] [Accepted: 08/08/2013] [Indexed: 01/03/2023]
Abstract
The pathogenic yeast Cryptococcus neoformans secretes numerous proteins, such as heat shock proteins, by unconventional mechanisms during its interaction with host cells. Hsp70 is a conserved chaperone that plays important roles in various cellular processes, including the interaction of fungi with host immune cells. Here, we report that sera from individuals with cryptococcosis infection recognize a recombinant C. neoformans Hsp70 (Cn_rHsp70). Moreover, immunofluorescence assays using antibodies against Cn_rHsp70 revealed the localization of this protein at the cell surface mainly in association with the capsular network. We found that the addition of Cn_rHsp70 positively modulated the interaction of C. neoformans with human alveolar epithelial cells and decreased fungal killing by mouse macrophages, without affecting phagocytosis rates. Immunofluorescence analysis showed that there was a competitive association among the receptor, GXM and Cn_rHsp70, indicating that the Hsp70-binding sites in host cells appear to be shared by glucuronoxylomannan (GXM), the major capsular antigen in C. neoformans. Our observations suggest additional mechanisms by which Hsp70 influences the interaction of C. neoformans with host cells.
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Affiliation(s)
- Carolina P Silveira
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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19
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Filler SG. Can host receptors for fungi be targeted for treatment of fungal infections? Trends Microbiol 2013; 21:389-96. [PMID: 23796589 DOI: 10.1016/j.tim.2013.05.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Revised: 05/23/2013] [Accepted: 05/24/2013] [Indexed: 11/19/2022]
Abstract
The invasion and stimulation of normally non-phagocytic host cells, such as epithelial and endothelial cells, is a key step in the pathogenesis of many fungal infections. In most cases, host cell invasion and/or stimulation of a proinflammatory response is induced when proteins or carbohydrates on the fungal cell surface bind to receptors on the host cell. Although many of these fungal-host cell interactions have only been investigated in vitro, the therapeutic efficacy of blocking the host cell receptors for Candida albicans and Rhizopus oryzae has been demonstrated in experimental animal models of infection. We summarize recent studies of the fungal receptors on normally non-phagocytic host cells and the therapeutic implications of blocking these receptors.
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Affiliation(s)
- Scott G Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, 1124 West Carson Street, Torrance, CA 90502, USA.
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20
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Osherov N. Interaction of the pathogenic mold Aspergillus fumigatus with lung epithelial cells. Front Microbiol 2012; 3:346. [PMID: 23055997 PMCID: PMC3458433 DOI: 10.3389/fmicb.2012.00346] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2012] [Accepted: 09/08/2012] [Indexed: 02/02/2023] Open
Abstract
Aspergillus fumigatus is an opportunistic environmental mold that can cause severe allergic responses in atopic individuals and poses a life-threatening risk for severely immunocompromised patients. Infection is caused by inhalation of fungal spores (conidia) into the lungs. The initial point of contact between the fungus and the host is a monolayer of lung epithelial cells. Understanding how these cells react to fungal contact is crucial to elucidating the pathobiology of Aspergillus-related disease states. The experimental systems, both in vitro and in vivo, used to study these interactions, are described. Distinction is made between bronchial and alveolar epithelial cells. The experimental findings suggest that lung epithelial cells are more than just “innocent bystanders” or a purely physical barrier against infection. They can be better described as an active extension of our innate immune system, operating as a surveillance mechanism that can specifically identify fungal spores and activate an offensive response to block infection. This response includes the internalization of adherent conidia and the release of cytokines, antimicrobial peptides, and reactive oxygen species. In the case of allergy, lung epithelial cells can dampen an over-reactive immune response by releasing anti-inflammatory compounds such as kinurenine. This review summarizes our current knowledge regarding the interaction of A. fumigatus with lung epithelial cells. A better understanding of the interactions between A. fumigatus and lung epithelial cells has therapeutic implications, as stimulation or inhibition of the epithelial response may alter disease outcome.
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Affiliation(s)
- Nir Osherov
- Department of Clinical Microbiology and Immunology, Aspergillus and Antifungal Research Laboratory, Sackler School of Medicine, Tel-Aviv University Ramat-Aviv, Tel-Aviv, Israel
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21
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Abstract
The pathogenic fungus Cryptococcus neoformans exhibits a striking propensity to cause central nervous system (CNS) disease in people with HIV/AIDS. Given that cryptococcal infections are generally initiated by pulmonary colonization, dissemination requires that the fungus withstand phagocytic killing, cross the alveolar-capillary interface in the lung, survive in the circulatory system and breach the blood-brain barrier. We know little about the molecular mechanisms underlying dissemination, but there is a rapidly growing list of mutants that fail to cause CNS disease. These mutants reveal a remarkable diversity of functions and therefore illustrate the complexity of the cryptococcal-host interaction. The challenge now is to extend the analysis of these mutants to acquire a detailed understanding of each step in dissemination.
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22
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Vecchiarelli A, Monari C. Capsular Material of Cryptococcus neoformans: Virulence and Much More. Mycopathologia 2012; 173:375-386. [PMID: 22314939 DOI: 10.1007/s11046-011-9513-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2011] [Accepted: 11/28/2011] [Indexed: 01/08/2023]
Abstract
The capsule is generally considered one of the more powerful virulence factors of microorganisms, driving research in the field of microbial pathogenesis and in the development of vaccines. Cryptococcus neoformans is unique among the most common human fungal pathogens in that it possesses a complex polysaccharide capsule. This review focuses on the Cryptococcus neoformans capsule from the viewpoint of fungal pathogenesis, and the effective immune response target of the capsule's main component, glucuronoxylomannan.
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Affiliation(s)
- A Vecchiarelli
- Department of Experimental Medicine and Biochemical Sciences, Microbiology Section, University of Perugia, Via del Giochetto, 06126, Perugia, Italy,
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23
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Figueiredo RT, Carneiro LAM, Bozza MT. Fungal surface and innate immune recognition of filamentous fungi. Front Microbiol 2011; 2:248. [PMID: 22194732 PMCID: PMC3242297 DOI: 10.3389/fmicb.2011.00248] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2011] [Accepted: 11/23/2011] [Indexed: 01/13/2023] Open
Abstract
The innate immune system performs specific detection of molecules from infectious agents through pattern recognition receptors. This recognition triggers inflammatory responses and activation of microbicidal mechanisms by leukocytes. Infections caused by filamentous fungi have increased in incidence and represent an important cause of mortality and morbidity especially in individuals with immunosuppression. This review will discuss the innate immune recognition of filamentous fungi molecules and its importance to infection control and disease.
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Affiliation(s)
- Rodrigo T Figueiredo
- Instituto de Ciências Biomédicas/Pólo de Xerém, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil
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24
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Grechi J, Marinho-Carvalho M, Zancan P, Cinelli LP, Gomes AMO, Rodrigues ML, Nimrichter L, Sola-Penna M. Glucuronoxylomannan from Cryptococcus neoformans down-regulates the enzyme 6-phosphofructo-1-kinase of macrophages. J Biol Chem 2011; 286:14820-9. [PMID: 21388964 DOI: 10.1074/jbc.m110.177030] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The encapsulated yeast Cryptococcus neoformans is the causative agent of cryptococosis, an opportunistic life-threatening infection. C. neoformans is coated by a polysaccharide capsule mainly composed of glucuronoxylomannan (GXM). GXM is considered a key virulence factor of this pathogen. The present work aimed at evaluating the effects of GXM on the key glycolytic enzyme, 6-phosphofructo-1-kinase (PFK). GXM inhibited PFK activity in cultured murine macrophages in both dose- and time-dependent manners, which occurred in parallel to cell viability decrease. The polysaccharide also inhibited purified PFK, promoting a decrease on the enzyme affinity for its substrates. In macrophages GXM and PFK partially co-localized, suggesting that internalized polysaccharide directly may interact with this enzyme. The mechanism of PFK inhibition involved dissociation of tetramers into weakly active dimers, as revealed by fluorescence spectroscopy. Allosteric modulators of the enzyme able to stabilize its tetrameric conformation attenuated the inhibition promoted by GXM. Altogether, our results suggest that the mechanism of GXM-induced cell death involves the inhibition of the glycolytic flux.
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Affiliation(s)
- Juliana Grechi
- Laboratório de Enzimologia e Controle do Metabolismo, Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ 21941-590, Brazil
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25
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Figueiredo RT, Fernandez PL, Dutra FF, González Y, Lopes LC, Bittencourt VCB, Sassaki GL, Barreto-Bergter E, Bozza MT. TLR4 recognizes Pseudallescheria boydii conidia and purified rhamnomannans. J Biol Chem 2010; 285:40714-23. [PMID: 20959459 PMCID: PMC3003371 DOI: 10.1074/jbc.m110.181255] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 10/14/2010] [Indexed: 01/09/2023] Open
Abstract
Pseudallescheria boydii (Scedosporium apiospermum) is a saprophytic fungus widespread in the environment, and has recently emerged as an agent of localized as well as disseminated infections, particularly mycetoma, in immunocompromised and immunocompetent hosts. We have previously shown that highly purified α-glucan from P. boydii activates macrophages through Toll-like receptor TLR2, however, the mechanism of P. boydii recognition by macrophage is largely unknown. In this work, we investigated the role of innate immune receptors in the recognition of P. boydii. Macrophages responded to P. boydii conidia and hyphae with secretion of proinflammatory cytokines. The activation of macrophages by P. boydii conidia required functional MyD88, TLR4, and CD14, whereas stimulation by hyphae was independent of TLR4 and TLR2 signaling. Removal of peptidorhamnomannans from P. boydii conidia abolished induction of cytokines by macrophages. A fraction highly enriched in rhamnomannans was obtained and characterized by NMR, high performance TLC, and GC-MS. Preparation of rhamnomannans derived from P. boydii triggered cytokine release by macrophages, as well as MAPKs phosphorylation and IκBα degradation. Cytokine release induced by P. boydii-derived rhamnomannans was dependent on TLR4 recognition and required the presence of non-reducing end units of rhamnose of the rhamnomannan, but not O-linked oligosaccharides from the peptidorhamnomannan. These results imply that TLR4 recognizes P. boydii conidia and this recognition is at least in part due to rhamnomannans expressed on the surface of P. boydii.
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Affiliation(s)
- Rodrigo T. Figueiredo
- From the Departamento de Imunologia, Laboratório de Inflamação e Imunidade, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 941-902 Brazil
- the Pólo de Xerém, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 941-902 Brazil
| | - Patrícia L. Fernandez
- From the Departamento de Imunologia, Laboratório de Inflamação e Imunidade, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 941-902 Brazil
- INDICASAT, Institute of Scientific Investigations and High Technology Services, Ciudad de Panamá, 843-01103 Panamá
| | - Fabianno F. Dutra
- From the Departamento de Imunologia, Laboratório de Inflamação e Imunidade, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 941-902 Brazil
| | - Yissett González
- INDICASAT, Institute of Scientific Investigations and High Technology Services, Ciudad de Panamá, 843-01103 Panamá
| | - Lívia Cristina Lopes
- the Departamento de Microbiologia Geral, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 941-902 Brazil
| | - Vera Carolina B. Bittencourt
- the Departamento de Microbiologia Geral, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 941-902 Brazil
- the Universidade Federal do Estado do Rio de Janeiro, Rio de Janeiro, 20211-040 Brazil, and
| | - Guilherme L. Sassaki
- the Departamento de Bioquímica, Universidade Federal do Paraná, Curitiba, 81531-990 Brazil
| | - Eliana Barreto-Bergter
- the Departamento de Microbiologia Geral, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 941-902 Brazil
| | - Marcelo T. Bozza
- From the Departamento de Imunologia, Laboratório de Inflamação e Imunidade, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 941-902 Brazil
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26
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Rodrigues ML, Fonseca FL, Frases S, Casadevall A, Nimrichter L. The still obscure attributes of cryptococcal glucuronoxylomannan. Med Mycol 2010; 47:783-8. [PMID: 19343609 DOI: 10.3109/13693780902788621] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Glucuronoxylomannan (GXM) is the major capsular polysaccharide of Cryptococcus neoformans. It is essential for fungal virulence and causes a number of deleterious effects to host cells. During the last decades, most of the experimental models designed to study the roles of GXM during cryptococcal infection were based on the stimulation of animal cells. This most commonly involved macrophages or other effector cells, with polysaccharide fractions obtained by precipitation with cationic detergents. More recently, it has been demonstrated that GXM interferes with the physiological state of other target cells, such as the epithelium. In addition, recent studies indicate that the structure of the polysaccharide and, consequently, its functions vary according with the method used for its purification. This raises questions as to what is native GXM and the significance of prior studies. In this paper, we discuss some of the aspects of GXM that are still poorly explored in the current literature, including the relevance of the polysaccharide in the interaction of cryptococci with non-phagocytic cells and the relationship between its structure and biological activity.
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Affiliation(s)
- Marcio L Rodrigues
- Laboratório de Estudos Integrados em Bioquímica Microbiana, Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, Brazil.
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27
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Frases S, Pontes B, Nimrichter L, Rodrigues ML, Viana NB, Casadevall A. The elastic properties of the Cryptococcus neoformans capsule. Biophys J 2009; 97:937-45. [PMID: 19686640 DOI: 10.1016/j.bpj.2009.04.043] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2009] [Revised: 04/07/2009] [Accepted: 04/15/2009] [Indexed: 11/29/2022] Open
Abstract
Microbial capsules are important for virulence, but their architecture and physical properties are poorly understood. The human pathogenic fungus Cryptococcus neoformans has a large polysaccharide capsule that is necessary for virulence and is the target of protective antibody responses. To study the C. neoformans capsule we developed what we believe is a new approach whereby we probed the capsular elastic properties by applying forces using polystyrene beads manipulated with optical tweezers. This method allowed us to determine the Young's modulus for the capsule in various conditions that affect capsule growth. The results indicate that the Young's modulus of the capsule decreases with its size and increases with the Ca(2+) concentration in solution. Also, capsular polysaccharide manifests an unexpected affinity for polystyrene beads, a property that may function in attachment to host cells and environmental structures. Bead probing with optical tweezers provides a new, nondestructive method that may have wide applicability for studying the effects of growth conditions, immune components, and drugs on capsular properties.
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Affiliation(s)
- Susana Frases
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, The Bronx, New York, USA.
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28
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The capsule of the fungal pathogen Cryptococcus neoformans. ADVANCES IN APPLIED MICROBIOLOGY 2009; 68:133-216. [PMID: 19426855 DOI: 10.1016/s0065-2164(09)01204-0] [Citation(s) in RCA: 321] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The capsule of the fungal pathogen Cryptococcus neoformans has been studied extensively in recent decades and a large body of information is now available to the scientific community. Well-known aspects of the capsule include its structure, antigenic properties and its function as a virulence factor. The capsule is composed primarily of two polysaccharides, glucuronoxylomannan (GXM) and galactoxylomannan (GalXM), in addition to a smaller proportion of mannoproteins (MPs). Most of the studies on the composition of the capsule have focused on GXM, which comprises more than 90% of the capsule's polysaccharide mass. It is GalXM, however, that is of particular scientific interest because of its immunological properties. The molecular structure of these polysaccharides is very complex and has not yet been fully elucidated. Both GXM and GalXM are high molecular mass polymers with the mass of GXM equaling roughly 10 times that of GalXM. Recent findings suggest, however, that the actual molecular weight might be different to what it has traditionally been thought to be. In addition to their structural roles in the polysaccharide capsule, these molecules have been associated with many deleterious effects on the immune response. Capsular components are therefore considered key virulence determinants in C. neoformans, which has motivated their use in vaccines and made them targets for monoclonal antibody treatments. In this review, we will provide an update on the current knowledge of the C. neoformans capsule, covering aspects related to its structure, synthesis and particularly, its role as a virulence factor.
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Nimrichter L, Rodrigues ML, Barreto-Bergter E, Travassos LR. Sophisticated Functions for a Simple Molecule: The Role of Glucosylceramides in Fungal Cells. Lipid Insights 2008. [DOI: 10.4137/lpi.s1014] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
It is well known that mammalian glycosphingolipids (GSL) play key roles in different physiological and pathophysiological processes. The simplest GSL, glucosylceramide (GlcCer), is formed through the enzymatic transfer of glucose to a ceramide moiety. In mammalian cells this molecule is the building block for the synthesis of lactosylceramides and many other complex GSLs. In fungal cells GlcCer is a major neutral GSL that has been considered during decades merely as a structural component of cell membranes. The recent literature, however, describes the participation of fungal GlcCer in vital processes such as secretion, cell wall assembly, recognition by the immune system and regulation of virulence. In this review we discuss the most recent information regarding fungal GlcCer, including (i) new aspects of GlcCer metabolism, (ii) the involvement of these molecules in virulence mechanisms, (iii) their role as targets of new antifungal drugs and immunotherapeutic agents and, finally, (v) their potential participation on cellular signaling in response to different stimuli.
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Affiliation(s)
- Leonardo Nimrichter
- Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-590, Brazil
| | - Marcio L. Rodrigues
- Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-590, Brazil
| | - Eliana Barreto-Bergter
- Instituto de Microbiologia Professor Paulo de Góes, Universidade Federal do Rio de Janeiro, 21941-590, Brazil
| | - Luiz R. Travassos
- Unidade de Oncologia Experimental and Disciplina de Biologia Celular, Universidade Federal de São Paulo; São Paulo, SP 04023-062, Brazil
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Guillot L, Carroll SF, Badawy M, Qureshi ST. Cryptococcus neoformans induces IL-8 secretion and CXCL1 expression by human bronchial epithelial cells. Respir Res 2008; 9:9. [PMID: 18211687 PMCID: PMC2254606 DOI: 10.1186/1465-9921-9-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2007] [Accepted: 01/22/2008] [Indexed: 11/10/2022] Open
Abstract
Background Cryptococcus neoformans (C. neoformans) is a globally distributed fungal pathogen with the potential to cause serious disease, particularly among immune compromised hosts. Exposure to this organism is believed to occur by inhalation and may result in pneumonia and/or disseminated infection of the brain as well as other organs. Little is known about the role of airway epithelial cells in cryptococcal recognition or their ability to induce an inflammatory response. Methods Immortalized BEAS-2B bronchial epithelial cells and primary normal human bronchial epithelium (NHBE) were stimulated in vitro with encapsulated or acapsular C. neoformans cultivated at room temperature or 37°C. Activation of bronchial epithelial cells was characterized by analysis of inflammatory cytokine and chemokine expression, transcription factor activation, fungal-host cell association, and host cell damage. Results Viable C. neoformans is a strong activator of BEAS-2B cells, resulting in the production of the neutrophil chemokine Interleukin (IL)-8 in a time- and dose-dependent manner. IL-8 production was observed only in response to acapsular C. neoformans that was grown at 37°C. C. neoformans was also able to induce the expression of the chemokine CXCL1 and the transcription factor CAAT/enhancer-binding protein beta (CEBP/β) in BEAS-2B cells. NHBE was highly responsive to stimulation with C. neoformans; in addition to transcriptional up regulation of CXCL1, these primary cells exhibited the greatest IL-8 secretion and cell damage in response to stimulation with an acapsular strain of C. neoformans. Conclusion This study demonstrates that human bronchial epithelial cells mediate an acute inflammatory response to C. neoformans and are susceptible to damage by this fungal pathogen. The presence of capsular polysaccharide and in vitro fungal culture conditions modulate the host inflammatory response to C. neoformans. Human bronchial epithelial cells are likely to contribute to the initial stages of pulmonary host defense in vivo.
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Affiliation(s)
- Loïc Guillot
- McGill Centre for the Study of Host Resistance, Room L11-403, 1650 Cedar Avenue, Montreal, QC, H3G 1A4, Canada.
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