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Dunne K, Reece E, McClean S, Doyle S, Rogers TR, Murphy P, Renwick J. Aspergillus fumigatus Supernatants Disrupt Bronchial Epithelial Monolayers: Potential Role for Enhanced Invasion in Cystic Fibrosis. J Fungi (Basel) 2023; 9:jof9040490. [PMID: 37108944 PMCID: PMC10141846 DOI: 10.3390/jof9040490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/14/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
Aspergillus fumigatus is the most commonly isolated fungus in chronic lung diseases, with a prevalence of up to 60% in cystic fibrosis patients. Despite this, the impact of A. fumigatus colonisation on lung epithelia has not been thoroughly explored. We investigated the influence of A. fumigatus supernatants and the secondary metabolite, gliotoxin, on human bronchial epithelial cells (HBE) and CF bronchial epithelial (CFBE) cells. CFBE (F508del CFBE41o-) and HBE (16HBE14o-) trans-epithelial electrical resistance (TEER) was measured following exposure to A. fumigatus reference and clinical isolates, a gliotoxin-deficient mutant (ΔgliG) and pure gliotoxin. The impact on tight junction (TJ) proteins, zonula occludens-1 (ZO-1) and junctional adhesion molecule-A (JAM-A) were determined by western blot analysis and confocal microscopy. A. fumigatus conidia and supernatants caused significant disruption to CFBE and HBE TJs within 24 h. Supernatants from later cultures (72 h) caused the greatest disruption while ΔgliG mutant supernatants caused no disruption to TJ integrity. The ZO-1 and JAM-A distribution in epithelial monolayers were altered by A. fumigatus supernatants but not by ΔgliG supernatants, suggesting that gliotoxin is involved in this process. The fact that ΔgliG conidia were still capable of disrupting epithelial monolayers indicates that direct cell-cell contact also plays a role, independently of gliotoxin production. Gliotoxin is capable of disrupting TJ integrity which has the potential to contribute to airway damage, and enhance microbial invasion and sensitisation in CF.
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Affiliation(s)
- Katie Dunne
- Discipline of Clinical Microbiology, School of Medicine, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Emma Reece
- Discipline of Clinical Microbiology, School of Medicine, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Siobhán McClean
- School of Biomolecular and Biomedical Science, University College Dublin, Belfield, D04 V1W8 Dublin, Ireland
| | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, W23 F2K8 Kildare, Ireland
| | - Thomas R Rogers
- Discipline of Clinical Microbiology, School of Medicine, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Philip Murphy
- Discipline of Clinical Microbiology, School of Medicine, Trinity College Dublin, D02 PN40 Dublin, Ireland
| | - Julie Renwick
- Discipline of Clinical Microbiology, School of Medicine, Trinity College Dublin, D02 PN40 Dublin, Ireland
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Amoebae as Targets for Toxins or Effectors Secreted by Mammalian Pathogens. Toxins (Basel) 2021; 13:toxins13080526. [PMID: 34437397 PMCID: PMC8402458 DOI: 10.3390/toxins13080526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 07/26/2021] [Accepted: 07/26/2021] [Indexed: 11/28/2022] Open
Abstract
Numerous microorganisms, pathogenic for mammals, come from the environment where they encounter predators such as free-living amoebae (FLA). The selective pressure due to this interaction could have generated virulence traits that are deleterious for amoebae and represents a weapon against mammals. Toxins are one of these powerful tools that are essential for bacteria or fungi to survive. Which amoebae are used as a model to study the effects of toxins? What amoeba functions have been reported to be disrupted by toxins and bacterial secreted factors? Do bacteria and fungi effectors affect eukaryotic cells similarly? Here, we review some studies allowing to answer these questions, highlighting the necessity to extend investigations of microbial pathogenicity, from mammals to the environmental reservoir that are amoebae.
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de Faria LV, do Carmo PHF, da Costa MC, Peres NTA, Rodrigues Chagas IA, Furst C, Ferreira GF, Costa AO, Santos DA. Acanthamoeba castellanii as an alternative interaction model for the dermatophyte Trichophyton rubrum. Mycoses 2020; 63:1331-1340. [PMID: 32869415 DOI: 10.1111/myc.13173] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/13/2020] [Accepted: 08/19/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Trichophyton rubrum (Tr) is the main aetiological agent of human dermatophytosis, being isolated from the environment and keratinised tissues. In the environment, Tr can interact with other organisms, such as free-living amoebas (FLA), which can act as an alternative host system to study the interaction between microbes and phagocytic cells. OBJECTIVES To characterise the Acanthamoeba castellanii (ALX)-Tr interaction. METHODS Interaction was characterised in three conditions: trophozoites (PYG), late (PYG/NES) and early (NES) encystation stimulus, evaluating encystation kinetics, phagocytosis, exocytosis and fungicidal activity dynamics. RESULTS Tr was able to induce ALX encystation and be internalised by ALX. The number of internalised conidia was high at 1 hour, and ALX presented fungicidal activity with increased intracellular ROS production and exocytosis. In PYG/NES, phagocytosis and ROS production were reduced, with decreased ALX's fungicidal activity. However, in NES there was an increased fungal engulfment, and a reduced ROS production and higher fungal burden. Furthermore, exogenous mannose decreased phagocytosis of Tr conidia, and divalent cations induced ROS production and increased ALX's fungicidal activity. Interestingly, phagocytosis was reduced in the presence of cytoskeleton inhibitor, but exocytosis was increased, suggesting that Tr conidia may have alternative pathways to escape ALX's cells. CONCLUSION A castellanii is a proper model for studying Tr-FLA interaction, since ALX can engulf, produce ROS and kill Tr, and all these parameters are influenced by an encystation stimulus and divalent cations. Moreover, this interaction is likely to occur in the environment implicating in the adaptation to environmental stressful conditions in both organisms.
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Affiliation(s)
- Lucas V de Faria
- Laboratório de Micologia, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Paulo H F do Carmo
- Laboratório de Micologia, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Marliete C da Costa
- Laboratório de Micologia, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Nalu T A Peres
- Laboratório de Micologia, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Isabela A Rodrigues Chagas
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Cinthia Furst
- Departamento de Patologia, Centro Ciências da Saúde, Universidade Federal do Espírito Santo, Vitoria, Brazil
| | - Gabriella F Ferreira
- Programa Multicêntrico de Pós Graduação em Bioquímica e Biologia Molecular, Universidade Federal de Juiz de Fora, Governador Valadares, Brazil
| | - Adriana O Costa
- Departamento de Análises Clínicas e Toxicológicas, Faculdade de Farmácia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Daniel A Santos
- Laboratório de Micologia, Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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The 'Amoeboid Predator-Fungal Animal Virulence' Hypothesis. J Fungi (Basel) 2019; 5:jof5010010. [PMID: 30669554 PMCID: PMC6463022 DOI: 10.3390/jof5010010] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 01/15/2019] [Accepted: 01/19/2019] [Indexed: 01/22/2023] Open
Abstract
The observation that some aspects of amoeba-fungal interactions resemble animal phagocytic cell-fungal interactions, together with the finding that amoeba passage can enhance the virulence of some pathogenic fungi, has stimulated interest in the amoeba as a model system for the study of fungal virulence. Amoeba provide a relatively easy and cheap model system where multiple variables can be controlled for the study of fungi-protozoal (amoeba) interactions. Consequently, there have been significant efforts to study fungal⁻amoeba interactions in the laboratory, which have already provided new insights into the origin of fungal virulence as well as suggested new avenues for experimentation. In this essay we review the available literature, which highlights the varied nature of amoeba-fungal interactions and suggests some unsolved questions that are potential areas for future investigation. Overall, results from multiple independent groups support the 'amoeboid predator⁻fungal animal virulence hypothesis', which posits that fungal cell predation by amoeba can select for traits that also function during animal infection to promote their survival and thus contribute to virulence.
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Novohradská S, Ferling I, Hillmann F. Exploring Virulence Determinants of Filamentous Fungal Pathogens through Interactions with Soil Amoebae. Front Cell Infect Microbiol 2017; 7:497. [PMID: 29259922 PMCID: PMC5723301 DOI: 10.3389/fcimb.2017.00497] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 11/20/2017] [Indexed: 01/15/2023] Open
Abstract
Infections with filamentous fungi are common to all animals, but attention is rising especially due to the increasing incidence and high mortality rates observed in immunocompromised human individuals. Here, Aspergillus fumigatus and other members of its genus are the leading causative agents. Attributes like their saprophytic life-style in various ecological niches coupled with nutritional flexibility and a broad host range have fostered the hypothesis that environmental predators could have been the actual target for some of their virulence determinants. In this mini review, we have merged the recent findings focused on the potential dual-use of fungal defense strategies against innate immune cells and soil amoebae as natural phagocytes. Well-established virulence attributes like the melanized surface of fungal conidia or their capacity to produce toxic secondary metabolites have also been found to be protective against the model amoeba Dictyostelium discoideum. Some of the recent advances during interaction studies with human cells have further promoted the adaptation of other amoeba infection models, including the wide-spread generalist Acanthamoeba castellanii, or less prominent representatives like Vermamoeba vermiformis. We further highlight prospects and limits of these natural phagocyte models with regard to the infection biology of filamentous fungi and in comparison to the phagocytes of the innate immune system.
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Affiliation(s)
- Silvia Novohradská
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Iuliia Ferling
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University Jena, Jena, Germany
| | - Falk Hillmann
- Evolution of Microbial Interactions, Leibniz Institute for Natural Product Research and Infection Biology-Hans Knöll Institute, Jena, Germany
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Vermamoeba vermiformis-Aspergillus fumigatus relationships and comparison with other phagocytic cells. Parasitol Res 2016; 115:4097-4105. [PMID: 27381330 DOI: 10.1007/s00436-016-5182-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 06/23/2016] [Indexed: 10/21/2022]
Abstract
Free living amoebae (FLA) are protists ubiquitously present in the environment. Aspergillus fumigatus is a mould responsible for severe deep-seated infections, and that can be recovered in the same habitats as the FLA. By conducting coculture experiments and fungal incubation with amoebal supernatants, we report herein that Vermamoeba vermiformis, a FLA present in hospital water systems, promotes filamentation and growth of A. fumigatus. This finding is of particular importance to institutions whose water systems might harbor FLA and could potentially be used by immunocompromised patients. Also, the relationships between V. vermiformis and A. fumigatus were compared to those between this fungus and two other phagocytic cells: Acanthamoeba castellanii, another FLA, and macrophage-like THP-1 cells. After 4 h of coincubation, the percentages of the three phagocytic cell types with adhered conidia were similar, even though the types of receptors between FLA and macrophagic cell seemed different. However, the percentage of THP-1 with internalized conidia was considerably lower (40 %) in comparison with the two other cell types (100 %). Thus, this study revealed that interactions between A. fumigatus and these three phagocytic cell types show similarities, even though it is premature to extrapolate these results to interpret relationships between A. fumigatus and macrophages.
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Dogi C, Alonso V, Fochesato A, Poloni V, Cavaglieri L. Comparison of toxicogenic and immunosuppressive capacity of Aspergillus fumigatus
strains isolated from clinical and corn silage samples. J Appl Microbiol 2014; 118:175-81. [DOI: 10.1111/jam.12673] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/15/2014] [Accepted: 10/19/2014] [Indexed: 11/29/2022]
Affiliation(s)
- C. Dogi
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires Argentina
| | - V. Alonso
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires Argentina
| | - A. Fochesato
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET); Buenos Aires; Argentina
| | - V. Poloni
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Tecnológicas (CONICET); Buenos Aires; Argentina
| | - L. Cavaglieri
- Departamento de Microbiología e Inmunología; Universidad Nacional de Río Cuarto; Río Cuarto Córdoba Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET); Buenos Aires Argentina
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Van Waeyenberghe L, Baré J, Pasmans F, Claeys M, Bert W, Haesebrouck F, Houf K, Martel A. Interaction of Aspergillus fumigatus conidia with Acanthamoeba castellanii parallels macrophage-fungus interactions. ENVIRONMENTAL MICROBIOLOGY REPORTS 2013; 5:819-824. [PMID: 24249290 DOI: 10.1111/1758-2229.12082] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 06/22/2013] [Indexed: 06/02/2023]
Abstract
Aspergillus fumigatus and free-living amoebae are common inhabitants of soil. Mechanisms of A. fumigatus to circumvent the amoeba's digestion may facilitate overcoming the vertebrate macrophage defence mechanisms. We performed co-culture experiments using A. fumigatus conidia and the amoeba Acanthamoeba castellanii. Approximately 25% of the amoebae ingested A. fumigatus conidia after 1 h of contact. During intra-amoebal passage, part of the ingested conidia was able to escape the food vacuole and to germinate inside the cytoplasm of A. castellanii. Fungal release into the extra-protozoan environment by exocytosis of conidia or by germination was observed with light and transmission electron microscopy. These processes resulted in structural changes in A. castellanii, leading to amoebal permeabilization without cell lysis. In conclusion, A. castellanii internalizes A. fumigatus conidia, resulting in fungal intracellular germination and subsequent amoebal death. As such, this interaction highly resembles that of A. fumigatus with mammalian and avian macrophages. This suggests that A. fumigatus virulence mechanisms to evade macrophage killing may be acquired by co-evolutionary interactions among A. fumigatus and environmental amoebae.
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Affiliation(s)
- Lieven Van Waeyenberghe
- Department of Pathology, Bacteriology and Avian Diseases, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, B-9820, Merelbeke, Belgium
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Utility of insects for studying human pathogens and evaluating new antimicrobial agents. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2013; 135:1-25. [PMID: 23604210 DOI: 10.1007/10_2013_194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
Abstract
Insect models, such as Galleria mellonella and Drosophila melanogaster have significant ethical, logistical, and economic advantages over mammalian models for the studies of infectious diseases. Using these models, various pathogenic microbes have been studied and many novel virulence genes have been identified. Notably, because insects are susceptible to a wide variety of human pathogens and have immune responses similar to those of mammals, they offer the opportunity to understand innate immune responses against human pathogens better. It is important to note that insect pathosystems have also offered a simple strategy to evaluate the efficacy and toxicity of many antimicrobial agents. Overall, insect models provide a rapid, inexpensive, and reliable way as complementary hosts to conventional vertebrate animal models to study pathogenesis and antimicrobial agents.
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Krappmann S. Tools to study molecular mechanisms of Aspergillus pathogenicity. Trends Microbiol 2006; 14:356-64. [PMID: 16806936 DOI: 10.1016/j.tim.2006.06.005] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2006] [Revised: 05/17/2006] [Accepted: 06/13/2006] [Indexed: 11/16/2022]
Abstract
The unique nature of Aspergillus fungi represents a challenge for scrutinizing the attributes that render these saprophytic microorganisms pathogenic or allergenic under certain environmental circumstances. Recent publication of the genomic sequence from an isolate of the major pathogen Aspergillus fumigatus denotes enormous progress in aiming at cellular features and gene products that contribute to its pathogenicity. Latest developments to study virulence-related characteristics comprise profiling techniques, conditional gene inactivation and precise manipulation of the genome by means of gene targeting. Advances in assessing the virulence potential of particular mutant strains in alternative test systems complement these approaches.
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Affiliation(s)
- Sven Krappmann
- Institute of Microbiology and Genetics, Department of Molecular Microbiology and Genetics, Georg-August University Göttingen, Grisebachstrasse 8, D-37077 Göttingen, Germany.
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Abstract
Aspergillus fumigatus is known to produce various immunosuppressive mycotoxins including gliotoxin. However, none of these mycotoxins has been confirmed as being directly related to the pathogenesis of aspergilli. Recent studies have made substantial progress in the determination of mycotoxins as virulence factors. Gliotoxin was found to be produced much faster than previously believed under certain culture conditions, such as at 37 degrees C and under high oxygen content, which is close to the environment in the host. Gliotoxin was also found to be detectable in the sera of aspergillosis mice and of aspergillosis patients. Based on these findings, it is becoming evident that gliotoxin is produced in the infected organs of patients of aspergillosis at a significant level. In addition to these known mycotoxins, A. fumigatus produces many mycotoxins apparently different from known toxins. From the aspect of gene analysis, the deletion of laeA was found to block the expression of metabolic gene clusters such as sterigmatocystin, and the gene is also expected to be related to the production of gliotoxin. The significance of mycotoxins as virulence factors will hopefully be clarified in the near future.
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Affiliation(s)
- K Kamei
- Research Center for Pathogenic Fungi and Microbial Toxicoses, Chiba University, Japan.
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