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Margalit A, Kavanagh K, Carolan JC. Characterization of the Proteomic Response of A549 Cells Following Sequential Exposure to Aspergillus fumigatus and Pseudomonas aeruginosa. J Proteome Res 2020; 19:279-291. [PMID: 31693381 DOI: 10.1021/acs.jproteome.9b00520] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Aspergillus fumigatus and Pseudomonas aeruginosa are the most prevalent fungal and bacterial pathogens associated with cystic-fibrosis-related infections, respectively. P. aeruginosa eventually predominates as the primary pathogen, though it is unknown why this is the case. Label-free quantitative proteomics was employed to investigate the cellular response of the alveolar epithelial cell line, A549, to coexposure of A. fumigatus and P. aeruginosa. These studies revealed a significant increase in the rate of P. aeruginosa proliferation where A. fumigatus was present. Shotgun proteomics performed on A549 cells exposed to either A. fumigatus or P. aeruginosa or to A. fumigatus and P. aeruginosa sequentially revealed distinct changes to the host cell proteome in response to either or both pathogens. While key signatures of infection were retained among all pathogen-exposed groups, including changes in mitochondrial activity and energy output, the relative abundance of proteins associated with endocytosis, phagosomes, and lysosomes was decreased in sequentially exposed cells compared to cells exposed to either pathogen. Our findings indicate that A. fumigatus renders A549 cells unable to internalize bacteria, thus providing an environment in which P. aeruginosa can proliferate. This research provides novel insights into the whole-cell proteomic response of A549 cells to A. fumigatus and P. aeruginosa and highlights distinct differences in the proteome following sequential exposure to both pathogens, which may explain why P. aeruginosa can predominate.
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Affiliation(s)
- Anatte Margalit
- Department of Biology , Maynooth University , Maynooth, Co. Kildare W23F2H6 , Ireland
| | - Kevin Kavanagh
- Department of Biology , Maynooth University , Maynooth, Co. Kildare W23F2H6 , Ireland
| | - James C Carolan
- Department of Biology , Maynooth University , Maynooth, Co. Kildare W23F2H6 , Ireland
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Han Z, Kautto L, Meyer W, Chen SCA, Nevalainen H. Effect of peptidases secreted by the opportunistic pathogen Scedosporium aurantiacum on human epithelial cells. Can J Microbiol 2019; 65:814-822. [PMID: 31265796 DOI: 10.1139/cjm-2019-0212] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Peptidases secreted by a clinical high-virulence Scedosporium aurantiacum isolate (strain WM 06.482; CBS 136046) under normoxic and hypoxic conditions were separated via size-exclusion chromatography, and peptidase activities present in each fraction were determined using class-specific substrates. The fractions demonstrating peptidase activity were assessed for their effects on the attachment and viability of A549 human lung epithelial cells in vitro. Of the peptidases detected in the size-exclusion chromatography fractions, the elastase-like peptidase reduced cell viability, the chymotrypsin-like peptidase was associated with cell detachment, and the cysteine peptidases were able to abolish both cell attachment and viability. The loss of cell viability and attachment became more prominent with an increase in the peptidase activity and could also be specifically prevented by addition of class-specific peptidase inhibitors. Our findings indicate that peptidases secreted by S. aurantiacum can breach the human alveolar epithelial cell barrier and, thus, may have a role in the pathobiology of the organism.
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Affiliation(s)
- Zhiping Han
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Liisa Kautto
- Department of Molecular Sciences, Macquarie University, Sydney, Australia.,Biomolecular Discovery and Design Research Centre, Macquarie University, Sydney, Australia
| | - Wieland Meyer
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Marie Bashir Institute for Infectious Diseases and Biosecurity, Sydney Medical School - Westmead Hospital, The University of Sydney, Westmead Institute for Medical Research, Sydney, Australia
| | - Sharon C-A Chen
- Molecular Mycology Research Laboratory, Centre for Infectious Diseases and Microbiology, Marie Bashir Institute for Infectious Diseases and Biosecurity, Sydney Medical School - Westmead Hospital, The University of Sydney, Westmead Institute for Medical Research, Sydney, Australia.,Centre for Infectious Diseases and Microbiology Laboratory Services, ICPMR, New South Wales Health Pathology, Westmead Hospital, Westmead, NSW, Australia
| | - Helena Nevalainen
- Department of Molecular Sciences, Macquarie University, Sydney, Australia.,Biomolecular Discovery and Design Research Centre, Macquarie University, Sydney, Australia
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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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Sharon H, Amar D, Levdansky E, Mircus G, Shadkchan Y, Shamir R, Osherov N. PrtT-regulated proteins secreted by Aspergillus fumigatus activate MAPK signaling in exposed A549 lung cells leading to necrotic cell death. PLoS One 2011; 6:e17509. [PMID: 21412410 PMCID: PMC3055868 DOI: 10.1371/journal.pone.0017509] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 02/04/2011] [Indexed: 12/03/2022] Open
Abstract
Aspergillus fumigatus is the most commonly encountered mold pathogen of humans, predominantly infecting the respiratory system. Colonization and penetration of the lung alveolar epithelium is a key but poorly understood step in the infection process. This study focused on identifying the transcriptional and cell-signaling responses activated in A549 alveolar carcinoma cells incubated in the presence of A. fumigatus wild-type and ΔPrtT protease-deficient germinating conidia and culture filtrates (CF). Microarray analysis of exposed A549 cells identified distinct classes of genes whose expression is altered in the presence of germinating conidia and CF and suggested the involvement of both NFkB and MAPK signaling pathways in mediating the cellular response. Phosphoprotein analysis of A549 cells confirmed that JNK and ERK1/2 are phosphorylated in response to CF from wild-type A. fumigatus and not phosphorylated in response to CF from the ΔPrtT protease-deficient strain. Inhibition of JNK or ERK1/2 kinase activity substantially decreased CF-induced cell damage, including cell peeling, actin-cytoskeleton damage, and reduction in metabolic activity and necrotic death. These results suggest that inhibition of MAPK-mediated host responses to treatment with A. fumigatus CF decreases cellular damage, a finding with possible clinical implications.
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Affiliation(s)
- Haim Sharon
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel-Aviv University, Ramat-Aviv, Tel-Aviv, Israel.
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Fallon JP, Reeves EP, Kavanagh K. Inhibition of neutrophil function following exposure to the Aspergillus fumigatus toxin fumagillin. J Med Microbiol 2010; 59:625-633. [PMID: 20203215 DOI: 10.1099/jmm.0.018192-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The filamentous fungus Aspergillus fumigatus produces a variety of enzymes and toxins that may facilitate fungal colonization of tissue and evasion of the host immune response. One such toxin, fumagillin, was investigated for its ability to inhibit the action of neutrophils, which are a central component of the innate immune response to microbial infection. Neutrophils exposed to 2 microg fumagillin ml(-1) for 25 min showed a significantly reduced ability to kill yeast cells (P<0.02), to phagocytose conidia of A. fumigatus (P<0.023) and to consume oxygen (P<0.032). The ability of neutrophils to generate superoxide is dependent upon the action of a functional NADPH oxidase complex which is composed of cytosolic (p40phox, p47phox, p67phox, Rac2) and membrane (gp91phox) proteins. Exposure of neutrophils to fumagillin inhibited the formation of the NADPH oxidase complex by blocking the translocation of p47phox from the cytosolic to the membrane fraction (P=0.02). In addition to the production of superoxide, neutrophils also undergo degranulation, which leads to the release of proteolytic enzymes that contribute to the microbicidal activity of the cell. Fumagillin-treated neutrophils showed reduced degranulation as evidenced by lower myeloperoxidase activity (P<0.019). Fumagillin-treated cells demonstrated reduced levels of F-actin, thus indicating that retarding the formation of F-actin may contribute to the inhibition of the structural rearrangements required in the activated neutrophil. This work indicates that fumagillin may contribute to reducing the local immune response by altering the activity of neutrophils and thus facilitate the continued persistence and growth of A. fumigatus in the host.
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Affiliation(s)
- John P Fallon
- Medical Mycology Unit, Department of Biology, National Institute for Cellular Biotechnology, National University of Ireland Maynooth, Co. Kildare, Ireland
| | - Emer P Reeves
- Respiratory Research Division, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland
| | - Kevin Kavanagh
- Medical Mycology Unit, Department of Biology, National Institute for Cellular Biotechnology, National University of Ireland Maynooth, Co. Kildare, Ireland
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Grovel O, Kerzaon I, Petit K, Robiou Du Pont T, Pouchus YF. A new and rapid bioassay for the detection of gliotoxin and related epipolythiodioxopiperazines produced by fungi. J Microbiol Methods 2006; 66:286-93. [PMID: 16451813 DOI: 10.1016/j.mimet.2005.12.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2005] [Revised: 12/06/2005] [Accepted: 12/13/2005] [Indexed: 11/21/2022]
Abstract
Gliotoxin is an immunosuppressive cytotoxin produced by numerous environmental or pathogenic fungal species. For this reason, it is one of the mycotoxins which must be systematically searched for in samples for biological control. In this study, a new, rapid and sensitive method for detecting gliotoxin has been developed. This bioassay is based on the induction of morphological changes in cultured cells (human KB cell line) by gliotoxin. Interpretation of the assay can be carried out after 1 h of incubation, either by direct microscopic observation, or with an automated microplate-reader at 630 nm. The limit of detection is 18-20 ng of gliotoxin in the well, depending on the used observation method. A high degree of specificity of the detection is brought about by the ability of the reducing reactant dithiothreitol to inhibit the biological activities of epipolythiodioxopiperazines (ETPs), such as gliotoxin, by reducing their polysulfide bridge. The bioassay allows a rapid primary screening of samples and a semi-quantitative evaluation of the gliotoxin concentration in extracts. The method has been used to study the gliotoxin production by different fungal strains, allowing to highlight 3 strains of Aspergillus fumigatus producing gliotoxin in various extracts.
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Affiliation(s)
- Olivier Grovel
- S.M.A.B., Université de Nantes, Pôle Mer et Littoral - Faculté de Pharmacie, BP53508- 44035 Nantes cedex 01, France.
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Gardiner DM, Waring P, Howlett BJ. The epipolythiodioxopiperazine (ETP) class of fungal toxins: distribution, mode of action, functions and biosynthesis. Microbiology (Reading) 2005; 151:1021-1032. [PMID: 15817772 DOI: 10.1099/mic.0.27847-0] [Citation(s) in RCA: 312] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Epipolythiodioxopiperazines (ETPs) are toxic secondary metabolites made only by fungi. The best-known ETP is gliotoxin, which appears to be a virulence factor associated with invasive aspergillosis of immunocompromised patients. The toxicity of ETPs is due to the presence of a disulphide bridge, which can inactivate proteins via reaction with thiol groups, and to the generation of reactive oxygen species by redox cycling. With the availability of complete fungal genome sequences and efficient gene-disruption techniques for fungi, approaches are now feasible to delineate biosynthetic pathways for ETPs and to gain insights into the evolution of such gene clusters.
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Affiliation(s)
- Donald M Gardiner
- School of Botany, The University of Melbourne, Victoria 3010, Australia
| | - Paul Waring
- School of Chemistry, Australian National University, ACT 0200, Australia
| | - Barbara J Howlett
- School of Botany, The University of Melbourne, Victoria 3010, Australia
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Fox M, Gray G, Kavanagh K, Lewis C, Doyle S. Detection of Aspergillus fumigatus mycotoxins: immunogen synthesis and immunoassay development. J Microbiol Methods 2004; 56:221-30. [PMID: 14744451 DOI: 10.1016/j.mimet.2003.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Immunological detection of secreted low molecular weight toxins represents a potentially novel means of diagnosing infection by the fungus Aspergillus fumigatus. Two such metabolites, gliotoxin and helvolic acid, were selected and conjugated to thyroglobulin for antisera generation in rabbits. Gliotoxin was initially activated using N-[p-maleimidophenyl] isocyanate (PMPI) and subsequently conjugated to S-acetyl thioglycolic acid N-hydroxysuccinimide-activated thyroglobulin, whereas helvolic acid was activated with N-(3-Dimethylaminopropyl)-N'-ethylcarbodiimide (EDC) in the presence of thyroglobulin prior to immunisation. To facilitate subsequent antisera evaluation, both toxins were similarly conjugated to bovine serum albumin (BSA). Matrix-Assisted Laser Desorption Ionisation-Time Of Flight (MALDI-TOF) mass spectrometry and SDS-PAGE analysis confirmed covalent attachment of toxins to BSA in the ratios of 15 and 2.4 mol per mol BSA for gliotoxin and helvolic acid, respectively. Resultant high titer antisera were capable of detecting both BSA-conjugated toxins (inhibitory concentration (IC)(50): 4-5 microg/ml). Free toxins were also detectable by competitive immunoassay, whereby 10 microg/ml free gliotoxin (30 microM) and helvolic acid (17 microM), respectively, inhibited antibody binding to cognate toxin-BSA previously immobilised on microwells. This work confirms that sensitive and specific antisera can be raised against fungal toxins and may have an application in diagnosing fungal infection.
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Affiliation(s)
- M Fox
- National Institute for Cellular Biotechnology, Department of Biology, National University of Ireland Maynooth, Maynooth, Co. Kildare, Ireland
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