1
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Lax C, Nicolás FE, Navarro E, Garre V. Molecular mechanisms that govern infection and antifungal resistance in Mucorales. Microbiol Mol Biol Rev 2024; 88:e0018822. [PMID: 38445820 PMCID: PMC10966947 DOI: 10.1128/mmbr.00188-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2024] Open
Abstract
SUMMARYThe World Health Organization has established a fungal priority pathogens list that includes species critical or highly important to human health. Among them is the order Mucorales, a fungal group comprising at least 39 species responsible for the life-threatening infection known as mucormycosis. Despite the continuous rise in cases and the poor prognosis due to innate resistance to most antifungal drugs used in the clinic, Mucorales has received limited attention, partly because of the difficulties in performing genetic manipulations. The COVID-19 pandemic has further escalated cases, with some patients experiencing the COVID-19-associated mucormycosis, highlighting the urgent need to increase knowledge about these fungi. This review addresses significant challenges in treating the disease, including delayed and poor diagnosis, the lack of accurate global incidence estimation, and the limited treatment options. Furthermore, it focuses on the most recent discoveries regarding the mechanisms and genes involved in the development of the disease, antifungal resistance, and the host defense response. Substantial advancements have been made in identifying key fungal genes responsible for invasion and tissue damage, host receptors exploited by the fungus to invade tissues, and mechanisms of antifungal resistance. This knowledge is expected to pave the way for the development of new antifungals to combat mucormycosis. In addition, we anticipate significant progress in characterizing Mucorales biology, particularly the mechanisms involved in pathogenesis and antifungal resistance, with the possibilities offered by CRISPR-Cas9 technology for genetic manipulation of the previously intractable Mucorales species.
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Affiliation(s)
- Carlos Lax
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Francisco E. Nicolás
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Eusebio Navarro
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
| | - Victoriano Garre
- Departamento de Genética y Microbiología, Facultad de Biología, Universidad de Murcia, Murcia, Spain
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2
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Jeican II, Horhat DI, Dumitru M, Florea A, Barbu-Tudoran L, Gheban BA, Anton V, Toader C, Aluaș M, Siserman CV, Balica N, Vrînceanu D, Albu S. COVID-19-Associated Rhino-Orbital Mucormycosis: Histological and Electron Microscopy Characteristics. Diagnostics (Basel) 2024; 14:429. [PMID: 38396469 PMCID: PMC10887990 DOI: 10.3390/diagnostics14040429] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2024] [Revised: 02/06/2024] [Accepted: 02/13/2024] [Indexed: 02/25/2024] Open
Abstract
COVID-19-associated rhino-orbital mucormycosis has become a new clinical entity. This study's aim was to evaluate the histopathological and ultramicroscopic morphological aspects of this fungal infection. This was an observational retrospective study on eight patients from three tertiary centers in Romania. The tissue samples collected during functional endoscopic sinus surgery were studied through histopathological examination, scanning electron microscopy, and transmission electron microscopy. In the histopathological examination, the morphological aspects characteristic of mucormycosis in all cases were identified: wide aseptate hyphae with right-angle ramifications, which invade blood vessels. One case presented perineural invasion into the perineural lymphatics. And in another case, mucormycosis-aspergillosis fungal coinfection was identified. Through scanning electron microscopy, long hyphae on the surface of the mucosa surrounded by cells belonging to the local immune system were identified in all samples, and bacterial biofilms were identified in half of the samples. Through transmission electron microscopy, aseptate hyphae and bacterial elements were identified in the majority of the samples. Rhino-orbital-cerebral mucormycosis associated with COVID-19 produces nasal sinus dysbiosis, which favors the appearance of bacterial biofilms. The way in which the infection develops depends on the interaction of the fungi with cells of the immune system.
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Affiliation(s)
- Ionuț Isaia Jeican
- Department of Anatomy and Embryology, Iuliu Hatieganu University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania;
| | - Delia Ioana Horhat
- Department of Ear-Nose-Throat, Victor Babes University of Medicine and Pharmacy Timisoara, 300041 Timisoara, Romania; (D.I.H.); (N.B.)
| | - Mihai Dumitru
- Department of Ear-Nose-Throat, Carol Davila University of Medicine and Pharmacy, 050472 Bucharest, Romania; (M.D.); (D.V.)
| | - Adrian Florea
- Department of Cell and Molecular Biology, Iuliu Hatieganu University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania;
| | - Lucian Barbu-Tudoran
- Electron Microscopy Laboratory Prof. C. Crăciun, Faculty of Biology and Geology, Babes-Bolyai University, 400006 Cluj-Napoca, Romania;
- Electron Microscopy Integrated Laboratory, National Institute for R&D of Isotopic and Molecular Technologies, 400293 Cluj-Napoca, Romania
| | - Bogdan-Alexandru Gheban
- Department of Histology, Iuliu Hatieganu University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania;
- Department of Pathology, Emergency Clinical County Hospital, 400347 Cluj-Napoca, Romania
| | - Vlad Anton
- Department of Medical Biochemistry, Iuliu Hatieganu University of Medicine and Pharmacy, 400349 Cluj-Napoca, Romania;
| | - Corneliu Toader
- Clinic of Neurosurgery, National Institute of Neurology and Neurovascular Diseases, 041914 Bucharest, Romania;
| | - Maria Aluaș
- Department of Oral Health, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Costel Vasile Siserman
- Institute of Legal Medicine, 400006 Cluj-Napoca, Romania;
- Department of Legal Medicine, Iuliu Hatieganu University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania
| | - Nicolae Balica
- Department of Ear-Nose-Throat, Victor Babes University of Medicine and Pharmacy Timisoara, 300041 Timisoara, Romania; (D.I.H.); (N.B.)
| | - Daniela Vrînceanu
- Department of Ear-Nose-Throat, Carol Davila University of Medicine and Pharmacy, 050472 Bucharest, Romania; (M.D.); (D.V.)
| | - Silviu Albu
- Department of Head and Neck Surgery and Otorhinolaryngology, University Clinical Hospital of Railway Company, Iuliu Hatieganu University of Medicine and Pharmacy, 400015 Cluj-Napoca, Romania;
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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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Matthaiou EI, Chiu W, Conrad C, Hsu J. Macrophage Lysosomal Alkalinization Drives Invasive Aspergillosis in a Mouse Cystic Fibrosis Model of Airway Transplantation. J Fungi (Basel) 2022; 8:751. [PMID: 35887506 PMCID: PMC9321820 DOI: 10.3390/jof8070751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 07/05/2022] [Accepted: 07/08/2022] [Indexed: 01/25/2023] Open
Abstract
Cystic fibrosis (CF) lung transplant recipients (LTRs) exhibit a disproportionately high rate of life-threatening invasive aspergillosis (IA). Loss of the cystic fibrosis transmembrane conductance regulator (CFTR-/-) in macrophages (mφs) has been associated with lyosomal alkalinization. We hypothesize that this alkalinization would persist in the iron-laden post-transplant microenvironment increasing the risk of IA. To investigate our hypothesis, we developed a murine CF orthotopic tracheal transplant (OTT) model. Iron levels were detected by immunofluorescence staining and colorimetric assays. Aspergillus fumigatus (Af) invasion was evaluated by Grocott methenamine silver staining. Phagocytosis and killing of Af conidia were examined by flow cytometry and confocal microscopy. pH and lysosomal acidification were measured by LysoSensorTM and LysotrackerTM, respectively. Af was more invasive in the CF airway transplant recipient compared to the WT recipient (p < 0.05). CFTR-/- mφs were alkaline at baseline, a characteristic that was increased with iron-overload. These CFTR-/- mφs were unable to phagocytose and kill Af conidia (p < 0.001). Poly(lactic-co-glycolic acid) (PLGA) nanoparticles acidified lysosomes, restoring the CFTR-/- mφs’ ability to clear conidia. Our results suggest that CFTR-/- mφs’ alkalinization interacts with the iron-loaded transplant microenvironment, decreasing the CF-mφs’ ability to kill Af conidia, which may explain the increased risk of IA. Therapeutic pH modulation after transplantation could decrease the risk of IA.
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Affiliation(s)
- Efthymia Iliana Matthaiou
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA 94304, USA; (E.I.M.); (W.C.)
| | - Wayland Chiu
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA 94304, USA; (E.I.M.); (W.C.)
- Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Carol Conrad
- Department of Pediatrics, Pulmonary Medicine, Stanford University School of Medicine, Stanford, CA 94304, USA;
| | - Joe Hsu
- Department of Medicine, Division of Pulmonary, Allergy and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA 94304, USA; (E.I.M.); (W.C.)
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Haist M, Ries F, Gunzer M, Bednarczyk M, Siegel E, Kuske M, Grabbe S, Radsak M, Bros M, Teschner D. Neutrophil-Specific Knockdown of β2 Integrins Impairs Antifungal Effector Functions and Aggravates the Course of Invasive Pulmonal Aspergillosis. Front Immunol 2022; 13:823121. [PMID: 35734179 PMCID: PMC9207500 DOI: 10.3389/fimmu.2022.823121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 04/28/2022] [Indexed: 12/12/2022] Open
Abstract
β2-integrins are heterodimeric surface receptors that are expressed specifically by leukocytes and consist of a variable α (CD11a-d) and a common β-subunit (CD18). Functional impairment of CD18, which causes leukocyte adhesion deficiency type-1 results in an immunocompromised state characterized by severe infections, such as invasive pulmonary aspergillosis (IPA). The underlying immune defects have largely been attributed to an impaired migratory and phagocytic activity of polymorphonuclear granulocytes (PMN). However, the exact contribution of β2-integrins for PMN functions in-vivo has not been elucidated yet, since the mouse models available so far display a constitutive CD18 knockout (CD18-/- or CD18hypo). To determine the PMN-specific role of β2-integrins for innate effector functions and pathogen control, we generated a mouse line with a Ly6G-specific knockdown of the common β-subunit (CD18Ly6G cKO). We characterized CD18Ly6G cKO mice in-vitro to confirm the PMN-specific knockdown of β2-integrins. Next, we investigated the clinical course of IPA in A. fumigatus infected CD18Ly6G cKO mice with regard to the fungal burden, pulmonary inflammation and PMN response towards A. fumigatus. Our results revealed that the β2-integrin knockdown was restricted to PMN and that CD18Ly6G cKO mice showed an aggravated course of IPA. In accordance, we observed a higher fungal burden and lower levels of proinflammatory innate cytokines, such as TNF-α, in lungs of IPA-infected CD18Ly6G cKO mice. Bronchoalveolar lavage revealed higher levels of CXCL1, a stronger PMN-infiltration, but concomitantly elevated apoptosis of PMN in lungs of CD18Ly6G cKO mice. Ex-vivo analysis further unveiled a strong impairment of PMN effector function, as reflected by an attenuated phagocytic activity, and a diminished generation of reactive oxygen species (ROS) and neutrophil-extracellular traps (NET) in CD18-deficient PMN. Overall, our study demonstrates that β2-integrins are required specifically for PMN effector functions and contribute to the clearance of A. fumigatus by infiltrating PMN, and the establishment of an inflammatory microenvironment in infected lungs.
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Affiliation(s)
- Maximilian Haist
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- *Correspondence: Maximilian Haist,
| | - Frederic Ries
- Department of Hematology, Medical Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Matthias Gunzer
- Institute for Experimental Immunology and Imaging, University Hospital, University Duisburg-Essen, Essen, Germany
- Leibniz-Institut für Analytische Wissenschaften ISAS -e.V, Dortmund, Germany
| | - Monika Bednarczyk
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Ekkehard Siegel
- Institute for Medical Microbiology and Hygiene, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Michael Kuske
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Stephan Grabbe
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Markus Radsak
- Department of Hematology, Medical Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Matthias Bros
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Daniel Teschner
- Department of Hematology, Medical Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
- Department of Internal Medicine II, University Hospital Würzburg, Würzburg, Germany
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6
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Ortiz SC, Pennington K, Thomson DD, Bertuzzi M. Novel Insights into Aspergillus fumigatus Pathogenesis and Host Response from State-of-the-Art Imaging of Host-Pathogen Interactions during Infection. J Fungi (Basel) 2022; 8:jof8030264. [PMID: 35330266 PMCID: PMC8954776 DOI: 10.3390/jof8030264] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 02/21/2022] [Accepted: 03/01/2022] [Indexed: 12/03/2022] Open
Abstract
Aspergillus fumigatus spores initiate more than 3,000,000 chronic and 300,000 invasive diseases annually, worldwide. Depending on the immune status of the host, inhalation of these spores can lead to a broad spectrum of disease, including invasive aspergillosis, which carries a 50% mortality rate overall; however, this mortality rate increases substantially if the infection is caused by azole-resistant strains or diagnosis is delayed or missed. Increasing resistance to existing antifungal treatments is becoming a major concern; for example, resistance to azoles (the first-line available oral drug against Aspergillus species) has risen by 40% since 2006. Despite high morbidity and mortality, the lack of an in-depth understanding of A. fumigatus pathogenesis and host response has hampered the development of novel therapeutic strategies for the clinical management of fungal infections. Recent advances in sample preparation, infection models and imaging techniques applied in vivo have addressed important gaps in fungal research, whilst questioning existing paradigms. This review highlights the successes and further potential of these recent technologies in understanding the host-pathogen interactions that lead to aspergillosis.
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Affiliation(s)
- Sébastien C. Ortiz
- Manchester Academic Health Science Centre, Core Technology Facility, Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Grafton Street, Manchester M13 9NT, UK; (S.C.O.); (K.P.)
| | - Katie Pennington
- Manchester Academic Health Science Centre, Core Technology Facility, Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Grafton Street, Manchester M13 9NT, UK; (S.C.O.); (K.P.)
| | - Darren D. Thomson
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter EX4 4QD, UK;
| | - Margherita Bertuzzi
- Manchester Academic Health Science Centre, Core Technology Facility, Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, The University of Manchester, Grafton Street, Manchester M13 9NT, UK; (S.C.O.); (K.P.)
- Correspondence:
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Kastelberg B, Ayubi T, Tubau-Juni N, Leber A, Hontecillas R, Bassaganya-Riera J, Kale SD. Nlrx1-Regulated Defense and Metabolic Responses to Aspergillus fumigatus Are Morphotype and Cell Type Specific. Front Immunol 2021; 12:749504. [PMID: 34790195 PMCID: PMC8591139 DOI: 10.3389/fimmu.2021.749504] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/29/2021] [Indexed: 12/20/2022] Open
Abstract
The Nlr family member X1 (Nlrx1) is an immuno-metabolic hub involved in mediating effective responses to virus, bacteria, fungi, cancer, and auto-immune diseases. We have previously shown that Nlrx1 is a critical regulator of immune signaling and mortality in several models of pulmonary fungal infection using the clinically relevant fungus Aspergillus fumigatus. In the absence of Nlrx1, hosts produce an enhanced Th2 response primarily by CD103+ dendritic cell populations resulting in enhanced mortality via immunopathogenesis as well as enhanced fungal burden. Here, we present our subsequent efforts showcasing loss of Nlrx1 resulting in a decreased ability of host cells to process A. fumigatus conidia in a cell-type-specific manner by BEAS-2B airway epithelial cells, alveolar macrophages, bone marrow-derived macrophages, but not bone marrow-derived neutrophils. Furthermore, loss of Nlrx1 results in a diminished ability to generate superoxide and/or generic reactive oxygen species during specific responses to fungal PAMPs, conidia, and hyphae. Analysis of glycolysis and mitochondrial function suggests that Nlrx1 is needed to appropriately shut down glycolysis in response to A. fumigatus conidia and increase glycolysis in response to hyphae in BEAS-2B cells. Blocking glycolysis and pentose phosphate pathway (PPP) via 2-DG and NADPH production through glucose-6-phosphate dehydrogenase inhibitor resulted in significantly diminished conidial processing in wild-type BEAS-2B cells to the levels of Nlrx1-deficient BEAS-2B cells. Our findings suggest a need for airway epithelial cells to generate NADPH for reactive oxygen species production in response to conidia via PPP. In context to fungal pulmonary infections, our results show that Nlrx1 plays significant roles in host defense via PPP modulation of several aspects of metabolism, particularly glycolysis, to facilitate conidia processing in addition to its critical role in regulating immune signaling.
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Bigot J, Guillot L, Guitard J, Ruffin M, Corvol H, Balloy V, Hennequin C. Bronchial Epithelial Cells on the Front Line to Fight Lung Infection-Causing Aspergillus fumigatus. Front Immunol 2020; 11:1041. [PMID: 32528481 PMCID: PMC7257779 DOI: 10.3389/fimmu.2020.01041] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/30/2020] [Indexed: 12/18/2022] Open
Abstract
Aspergillus fumigatus is an environmental filamentous fungus that can be pathogenic for humans, wherein it is responsible for a large variety of clinical forms ranging from allergic diseases to life-threatening disseminated infections. The contamination occurs by inhalation of conidia present in the air, and the first encounter of this fungus in the human host is most likely with the bronchial epithelial cells. Although alveolar macrophages have been widely studied in the Aspergillus–lung interaction, increasing evidence suggests that bronchial epithelium plays a key role in responding to the fungus. This review focuses on the innate immune response of the bronchial epithelial cells against A. fumigatus, the predominant pathogenic species. We have also detailed the molecular interactants and the effects of the different modes of interaction between these cells and the fungus.
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Affiliation(s)
- Jeanne Bigot
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Hôpital Saint-Antoine, Service de Parasitologie-Mycologie, Paris, France
| | - Loïc Guillot
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, Paris, France
| | - Juliette Guitard
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Hôpital Saint-Antoine, Service de Parasitologie-Mycologie, Paris, France
| | - Manon Ruffin
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, Paris, France
| | - Harriet Corvol
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Hôpital Trousseau, Service de Pneumologie Pédiatrique, Paris, France
| | - Viviane Balloy
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, Paris, France
| | - Christophe Hennequin
- Sorbonne Université, Inserm, Centre de Recherche Saint-Antoine, CRSA, AP-HP, Hôpital Saint-Antoine, Service de Parasitologie-Mycologie, Paris, France
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Abstract
Aspergillus fumigatus is a saprotrophic fungus; its primary habitat is the soil. In its ecological niche, the fungus has learned how to adapt and proliferate in hostile environments. This capacity has helped the fungus to resist and survive against human host defenses and, further, to be responsible for one of the most devastating lung infections in terms of morbidity and mortality. In this review, we will provide (i) a description of the biological cycle of A. fumigatus; (ii) a historical perspective of the spectrum of aspergillus disease and the current epidemiological status of these infections; (iii) an analysis of the modes of immune response against Aspergillus in immunocompetent and immunocompromised patients; (iv) an understanding of the pathways responsible for fungal virulence and their host molecular targets, with a specific focus on the cell wall; (v) the current status of the diagnosis of different clinical syndromes; and (vi) an overview of the available antifungal armamentarium and the therapeutic strategies in the clinical context. In addition, the emergence of new concepts, such as nutritional immunity and the integration and rewiring of multiple fungal metabolic activities occurring during lung invasion, has helped us to redefine the opportunistic pathogenesis of A. fumigatus.
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Affiliation(s)
- Jean-Paul Latgé
- School of Medicine, University of Crete, Heraklion, Crete, Greece
| | - Georgios Chamilos
- School of Medicine, University of Crete, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece
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Lichtheimia corymbifera Colonization Leading to Pulmonary Infection Can Be Prevented with Liposomal Amphotericin B in a New Murine Model. Antimicrob Agents Chemother 2019; 63:AAC.02544-18. [PMID: 31138564 DOI: 10.1128/aac.02544-18] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Accepted: 05/17/2019] [Indexed: 01/26/2023] Open
Abstract
The incidence of pulmonary mucormycosis is constantly increasing, especially in hematological patients staying in high-efficiency particulate air-filtered rooms. Pulmonary inhalation of spores may occur outside the hospital, leading to invasive disease once patients received chemotherapies. We developed a new pulmonary mucormycosis mouse model mimicking the expected pathophysiology in human to study antifungal drugs. Naive mice were inoculated intratracheally with Lichtheimia corymbifera spores. After 3 days, mice received corticosteroids and cyclophosphamide and secondarily developed the disease, while only 5% of the initial inoculum was present in the lungs at day 3. Lung colonization with L. corymbifera spores in immunocompetent mice can last at least 44 days. Antifungal drug was administered the day of immunosuppression. Injection of a single 15 mg/kg of body weight dose of liposomal amphotericin B significantly improved survival and pulmonary fungal burden compared with controls, whereas 80 mg/kg oral posaconazole did not. These results show that a unique dose of liposomal amphotericin B offers a real potential decolonization treatment to prevent infection in our mouse model of L. corymbifera lung colonization followed by lung infection.
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11
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Endocytic Markers Associated with the Internalization and Processing of Aspergillus fumigatus Conidia by BEAS-2B Cells. mSphere 2019; 4:4/1/e00663-18. [PMID: 30728282 PMCID: PMC6365614 DOI: 10.1128/msphere.00663-18] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Conidia from the fungus Aspergillus fumigatus are notorious for their ability to stay airborne. This characteristic is believed to allow conidia to penetrate into the cleanest environments. Several hundred conidia are thought to be inhaled each day by a given individual and then expelled by mucociliary clearance. Given that airway epithelial cells make up a significant portion of the pulmonary-air interface, we set out to determine the percentage of conidia that are actually internalized after initial contact with airway epithelial cells. We determined this through an in vitro assay using an immortalized bronchial airway epithelial cell line known as BEAS-2B. Our results suggest a small fraction of conidia are internalized by BEAS-2B cells, while the majority stay adherent to the surface of cells or are washed away during sample processing. Internalization of conidia was observed at 6 h postchallenge and not prior. Our data also indicate conidia are rendered metabolically inactive within 3 h of challenge, suggesting BEAS-2B cells process a large number of conidia without internalization in this early time frame. We have also identified several host endocytosis markers that localize around internalized conidia as well as contribute to the processing of conidia. Understanding how these host endocytosis markers affect the processing of internal and/or external conidia may provide a novel avenue for therapeutic development. Aspergillus fumigatus is a ubiquitous mold that produces small airborne conidia capable of traversing deep into the respiratory system. Recognition, processing, and clearance of A. fumigatus conidia by bronchial airway epithelial cells are thought to be relevant to host defense and immune signaling. Using z-stack confocal microscopy, we observed that only 10 to 20% of adherent conidia from the AF293 clinical isolate are internalized by BEAS-2B cells 6 h postchallenge and not prior. Similar percentages of internalization were observed for the CEA10 clinical isolate. A large subset of both AF293 and CEA10 conidia are rendered metabolically inactive without internalization at 3 h postchallenge by BEAS-2B cells. A significantly larger percentage of CEA10 conidia are metabolically active at 9 and 12 h postchallenge in comparison to the AF293 isolate, demonstrating heterogeneity among clinical isolates. We identified 7 host markers (caveolin, flotillin-2, RAB5C, RAB8B, RAB7A, 2xFYVE, and FAPP1) that consistently localized around internalized conidia 9 h postchallenge. Transient gene silencing of RAB5C, PIK3C3, and flotillin-2 resulted in a larger population of metabolically active conidia. Our findings emphasize the abundance of both host phosphatidylinositol 3-phosphate (PI3P) and PI4P around internalized conidia, as well as the importance of class III PI3P kinase for conidial processing. Therapeutic development focused on RAB5C-, PIK3C3-, and flotillin-2-mediated pathways may provide novel opportunities to modulate conidial processing and internalization. Determination of how contacted, external conidia are processed by airway epithelial cells may also provide a novel avenue to generate host-targeted therapeutics. IMPORTANCE Conidia from the fungus Aspergillus fumigatus are notorious for their ability to stay airborne. This characteristic is believed to allow conidia to penetrate into the cleanest environments. Several hundred conidia are thought to be inhaled each day by a given individual and then expelled by mucociliary clearance. Given that airway epithelial cells make up a significant portion of the pulmonary-air interface, we set out to determine the percentage of conidia that are actually internalized after initial contact with airway epithelial cells. We determined this through an in vitro assay using an immortalized bronchial airway epithelial cell line known as BEAS-2B. Our results suggest a small fraction of conidia are internalized by BEAS-2B cells, while the majority stay adherent to the surface of cells or are washed away during sample processing. Internalization of conidia was observed at 6 h postchallenge and not prior. Our data also indicate conidia are rendered metabolically inactive within 3 h of challenge, suggesting BEAS-2B cells process a large number of conidia without internalization in this early time frame. We have also identified several host endocytosis markers that localize around internalized conidia as well as contribute to the processing of conidia. Understanding how these host endocytosis markers affect the processing of internal and/or external conidia may provide a novel avenue for therapeutic development.
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Teschner D, Cholaszczyńska A, Ries F, Beckert H, Theobald M, Grabbe S, Radsak M, Bros M. CD11b Regulates Fungal Outgrowth but Not Neutrophil Recruitment in a Mouse Model of Invasive Pulmonary Aspergillosis. Front Immunol 2019; 10:123. [PMID: 30778357 PMCID: PMC6369709 DOI: 10.3389/fimmu.2019.00123] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 01/15/2019] [Indexed: 12/28/2022] Open
Abstract
ß2 integrin receptors consist of an alpha subunit (CD11a-CD11d) and CD18 as the common beta subunit, and are differentially expressed by leukocytes. ß2 integrins are required for cell-cell interaction, transendothelial migration, uptake of opsonized pathogens, and cell signaling processes. Functional loss of CD18—termed leukocyte-adhesion deficiency type 1 (LAD1)—results in an immunocompromised state characterized by frequent occurrence of severe infections. In immunosuppressed individuals Aspergillus fumigatus is a frequent cause of invasive pulmonary fungal infection, and often occurs in patients suffering from LAD1. Here, we asked for the importance of CD11b/CD18 also termed MAC-1 which is required for phagocytosis of opsonized A. fumigatus conidia by polymorphonuclear neutrophils (PMN) for control of pulmonary A. fumigatus infection. We show that CD11b−/− mice infected with A. fumigatus were unaffected in long term survival, similar to wild type (WT) mice. However, bronchoalveolar lavage (BAL) performed 1 day after infection revealed a higher lung infiltration of PMN in case of infected CD11b−/− mice than observed for WT mice. BAL derived from infected CD11b−/− mice also contained a higher amount of leukocyte-attracting CCL5 chemokine, but lower amounts of proinflammatory innate cytokines. In accordance, lung tissue of A. fumigatus infected CD11b−/− mice was characterized by lower cellular inflammation, and a higher fungal burden. In agreement, CD11b−/−PMN exerted lower phagocytic activity on serum-opsonized A. fumigatus conidia than WT PMN in vitro. Our study shows that MAC-1 is required for effective clearance of A. fumigatus by infiltrating PMN, and the establishment of an inflammatory microenvironment in infected lung. Enhanced infiltration of CD11b−/− PMN may serve to compensate impaired PMN function.
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Affiliation(s)
- Daniel Teschner
- Department of Hematology, Medical Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Anna Cholaszczyńska
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Frederic Ries
- Department of Hematology, Medical Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Hendrik Beckert
- Department of Pulmonary Medicine, University Medical Center Essen-Ruhrlandklinik, Essen, Germany
| | - Matthias Theobald
- Department of Hematology, Medical Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Stephan Grabbe
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Markus Radsak
- Department of Hematology, Medical Oncology and Pneumology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
| | - Matthias Bros
- Department of Dermatology, University Medical Center of the Johannes Gutenberg University, Mainz, Germany
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Toor A, Culibrk L, Singhera GK, Moon KM, Prudova A, Foster LJ, Moore MM, Dorscheid DR, Tebbutt SJ. Transcriptomic and proteomic host response to Aspergillus fumigatus conidia in an air-liquid interface model of human bronchial epithelium. PLoS One 2018; 13:e0209652. [PMID: 30589860 PMCID: PMC6307744 DOI: 10.1371/journal.pone.0209652] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 12/10/2018] [Indexed: 12/31/2022] Open
Abstract
Aspergillus fumigatus (A. fumigatus) is a wide-spread fungus that is a potent allergen in hypersensitive individuals but also an opportunistic pathogen in immunocompromised patients. It reproduces asexually by releasing airborne conidiospores (conidia). Upon inhalation, fungal conidia are capable of reaching the airway epithelial cells (AECs) in bronchial and alveolar tissues. Previous studies have predominantly used submerged monolayer cultures for studying this host-pathogen interaction; however, these cultures do not recapitulate the mucocililary differentiation phenotype of the in vivo epithelium in the respiratory tract. Thus, the aim of this study was to use well-differentiated primary human bronchial epithelial cells (HBECs) grown at the air-liquid interface (ALI) to determine their transcriptomic and proteomic responses following interaction with A. fumigatus conidia. We visualized conidial interaction with HBECs using confocal laser scanning microscopy (CLSM), and applied NanoString nCounter and shotgun proteomics to assess gene expression changes in the human cells upon interaction with A. fumigatus conidia. Western blot analysis was used to assess the expression of top three differentially expressed proteins, CALR, SET and NUCB2. CLSM showed that, unlike submerged monolayer cultures, well-differentiated ALI cultures of primary HBECs were estimated to internalize less than 1% of bound conidia. Nevertheless, transcriptomic and proteomic analyses revealed numerous differentially expressed host genes; these were enriched for pathways including apoptosis/autophagy, translation, unfolded protein response and cell cycle (up-regulated); complement and coagulation pathways, iron homeostasis, nonsense mediated decay and rRNA binding (down-regulated). CALR and SET were confirmed to be up-regulated in ALI cultures of primary HBECs upon exposure to A. fumigatus via western blot analysis. Therefore, using transcriptomics and proteomics approaches, ALI models recapitulating the bronchial epithelial barrier in the conductive zone of the respiratory tract can provide novel insights to the molecular response of bronchial epithelial cells upon exposure to A. fumigatus conidia.
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Affiliation(s)
- Amreen Toor
- Experimental Medicine, University of British Columbia, Vancouver, Canada
- Centre for Heart Lung Innovation, University of British Columbia and St. Paul’s Hospital, Vancouver, Canada
| | - Luka Culibrk
- Centre for Heart Lung Innovation, University of British Columbia and St. Paul’s Hospital, Vancouver, Canada
| | - Gurpreet K. Singhera
- Centre for Heart Lung Innovation, University of British Columbia and St. Paul’s Hospital, Vancouver, Canada
| | - Kyung-Mee Moon
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Anna Prudova
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Leonard J. Foster
- Department of Biochemistry & Molecular Biology, University of British Columbia, Vancouver, Canada
| | - Margo M. Moore
- Department of Biological Sciences, Simon Fraser University, Burnaby, Canada
| | - Delbert R. Dorscheid
- Centre for Heart Lung Innovation, University of British Columbia and St. Paul’s Hospital, Vancouver, Canada
- Department of Medicine, Division of Respiratory Medicine, University of British Columbia, Vancouver, Canada
| | - Scott J. Tebbutt
- Centre for Heart Lung Innovation, University of British Columbia and St. Paul’s Hospital, Vancouver, Canada
- Department of Medicine, Division of Respiratory Medicine, University of British Columbia, Vancouver, Canada
- Prevention of Organ Failure (PROOF) Centre of Excellence, Vancouver, Canada
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Feldman MB, Vyas JM, Mansour MK. It takes a village: Phagocytes play a central role in fungal immunity. Semin Cell Dev Biol 2018; 89:16-23. [PMID: 29727727 DOI: 10.1016/j.semcdb.2018.04.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 04/24/2018] [Indexed: 12/12/2022]
Abstract
Phagocytosis is an essential step in the innate immune response to invasive fungal infections. This process is carried out by a proverbial "village" of professional phagocytic cells, which have evolved efficient machinery to recognize and ingest pathogens, namely macrophages, neutrophils and dendritic cells. These innate immune cells drive early cytokine production, fungicidal activity, antigen presentation and activation of the adaptive immune system. Despite the development of antifungal agents with potent activity, the biological activity of professional phagocytic innate immune cells has proven indispensable in protecting a host from invasive fungal infections. Additionally, an emerging body of evidence suggests non-professional phagocytes, such as airway epithelial cells, carry out phagocytosis and may play a critical role in the elimination of fungal pathogens. Here, we review recent advances of phagocytosis by both professional and non-professional phagocytes in response to fungal pathogens, with a focus on invasive aspergillosis as a model disease.
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Affiliation(s)
- Michael B Feldman
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, MA 02114, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Jatin M Vyas
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114 USA; Harvard Medical School, Boston, MA 02115, USA
| | - Michael K Mansour
- Division of Infectious Diseases, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114 USA; Harvard Medical School, Boston, MA 02115, USA.
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15
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Fernandes J, Hamidi F, Leborgne R, Beau R, Castier Y, Mordant P, Boukkerou A, Latgé JP, Pretolani M. Penetration of the Human Pulmonary Epithelium by Aspergillus fumigatus Hyphae. J Infect Dis 2018; 218:1306-1313. [DOI: 10.1093/infdis/jiy298] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Accepted: 05/23/2018] [Indexed: 12/12/2022] Open
Affiliation(s)
- Julien Fernandes
- INSERM UMR1152, Physiopathologie et Epidémiologie des Maladies Respiratoires, Paris, France
- Université Paris Diderot, Sorbonne Paris-Cité, Faculté de Médecine, site Bichat, France
- Laboratory of Excellence INFLAMEX, Université Sorbonne Paris-Cité, France
- Département Hospitalo-Universitaire FIRE, Paris, France
| | - Fatima Hamidi
- INSERM UMR1152, Physiopathologie et Epidémiologie des Maladies Respiratoires, Paris, France
- Université Paris Diderot, Sorbonne Paris-Cité, Faculté de Médecine, site Bichat, France
- Laboratory of Excellence INFLAMEX, Université Sorbonne Paris-Cité, France
- Département Hospitalo-Universitaire FIRE, Paris, France
| | - Remi Leborgne
- ImagoSeine Electron Microscopy Facility, Institut Jacques Monod, Centre National de la Recherche Scientifique UMR 7592, Université Paris Diderot, Sorbonne Paris-Cité, France
| | - Remi Beau
- Unité des Aspergillus, Institut Pasteur, Paris, France
| | - Yves Castier
- INSERM UMR1152, Physiopathologie et Epidémiologie des Maladies Respiratoires, Paris, France
- Université Paris Diderot, Sorbonne Paris-Cité, Faculté de Médecine, site Bichat, France
- Laboratory of Excellence INFLAMEX, Université Sorbonne Paris-Cité, France
- Département Hospitalo-Universitaire FIRE, Paris, France
- Service de Chirurgie Thoracique, Groupement Hospitalier Universitaire Nord Bichat-Claude Bernard, Assistance Publique des Hopitaux de Paris, France
| | - Pierre Mordant
- INSERM UMR1152, Physiopathologie et Epidémiologie des Maladies Respiratoires, Paris, France
- Université Paris Diderot, Sorbonne Paris-Cité, Faculté de Médecine, site Bichat, France
- Laboratory of Excellence INFLAMEX, Université Sorbonne Paris-Cité, France
- Département Hospitalo-Universitaire FIRE, Paris, France
- Service de Chirurgie Thoracique, Groupement Hospitalier Universitaire Nord Bichat-Claude Bernard, Assistance Publique des Hopitaux de Paris, France
| | - Amira Boukkerou
- INSERM UMR1152, Physiopathologie et Epidémiologie des Maladies Respiratoires, Paris, France
- Université Paris Diderot, Sorbonne Paris-Cité, Faculté de Médecine, site Bichat, France
- Laboratory of Excellence INFLAMEX, Université Sorbonne Paris-Cité, France
- Département Hospitalo-Universitaire FIRE, Paris, France
| | | | - Marina Pretolani
- INSERM UMR1152, Physiopathologie et Epidémiologie des Maladies Respiratoires, Paris, France
- Université Paris Diderot, Sorbonne Paris-Cité, Faculté de Médecine, site Bichat, France
- Laboratory of Excellence INFLAMEX, Université Sorbonne Paris-Cité, France
- Département Hospitalo-Universitaire FIRE, Paris, France
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16
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Bertuzzi M, Hayes GE, Icheoku UJ, van Rhijn N, Denning DW, Osherov N, Bignell EM. Anti-Aspergillus Activities of the Respiratory Epithelium in Health and Disease. J Fungi (Basel) 2018; 4:E8. [PMID: 29371501 PMCID: PMC5872311 DOI: 10.3390/jof4010008] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 01/03/2018] [Accepted: 01/05/2018] [Indexed: 02/06/2023] Open
Abstract
Respiratory epithelia fulfil multiple roles beyond that of gaseous exchange, also acting as primary custodians of lung sterility and inflammatory homeostasis. Inhaled fungal spores pose a continual antigenic, and potentially pathogenic, challenge to lung integrity against which the human respiratory mucosa has developed various tolerance and defence strategies. However, respiratory disease and immune dysfunction frequently render the human lung susceptible to fungal diseases, the most common of which are the aspergilloses, a group of syndromes caused by inhaled spores of Aspergillus fumigatus. Inhaled Aspergillus spores enter into a multiplicity of interactions with respiratory epithelia, the mechanistic bases of which are only just becoming recognized as important drivers of disease, as well as possible therapeutic targets. In this mini-review we examine current understanding of Aspergillus-epithelial interactions and, based upon the very latest developments in the field, we explore two apparently opposing schools of thought which view epithelial uptake of Aspergillus spores as either a curative or disease-exacerbating event.
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Affiliation(s)
- Margherita Bertuzzi
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK.
| | - Gemma E Hayes
- Northern Devon Healthcare NHS Trust, North Devon District Hospital, Raleigh Park, Barnstaple EX31 4JB, UK.
| | - Uju J Icheoku
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK.
| | - Norman van Rhijn
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK.
| | - David W Denning
- The National Aspergillosis Centre, Education and Research Centre, Wythenshawe Hospital, Manchester University NHS Foundation Trust, Manchester M23 9LT, UK.
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Elaine M Bignell
- Manchester Fungal Infection Group, Faculty of Biology, Medicine and Health, University of Manchester, Manchester M13 9NT, UK.
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Croft CA, Culibrk L, Moore MM, Tebbutt SJ. Interactions of Aspergillus fumigatus Conidia with Airway Epithelial Cells: A Critical Review. Front Microbiol 2016; 7:472. [PMID: 27092126 PMCID: PMC4823921 DOI: 10.3389/fmicb.2016.00472] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 03/21/2016] [Indexed: 02/05/2023] Open
Abstract
Aspergillus fumigatus is an environmental filamentous fungus that also acts as an opportunistic pathogen able to cause a variety of symptoms, from an allergic response to a life-threatening disseminated fungal infection. The infectious agents are inhaled conidia whose first point of contact is most likely to be an airway epithelial cell (AEC). The interaction between epithelial cells and conidia is multifaceted and complex, and has implications for later steps in pathogenesis. Increasing evidence has demonstrated a key role for the airway epithelium in the response to respiratory pathogens, particularly at early stages of infection; therefore, elucidating the early stages of interaction of conidia with AECs is essential to understand the establishment of infection in cohorts of at-risk patients. Here, we present a comprehensive review of the early interactions between A. fumigatus and AECs, including bronchial and alveolar epithelial cells. We describe mechanisms of adhesion, internalization of conidia by AECs, the immune response of AECs, as well as the role of fungal virulence factors, and patterns of fungal gene expression characteristic of early infection. A clear understanding of the mechanisms involved in the early establishment of infection by A. fumigatus could point to novel targets for therapy and prophylaxis.
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Affiliation(s)
- Carys A Croft
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver BC, Canada
| | - Luka Culibrk
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, Vancouver BC, Canada
| | - Margo M Moore
- Department of Biological Sciences, Simon Fraser University, Burnaby BC, Canada
| | - Scott J Tebbutt
- Centre for Heart Lung Innovation, St. Paul's Hospital, University of British Columbia, VancouverBC, Canada; Prevention of Organ Failure Centre of Excellence, VancouverBC, Canada; Department of Medicine, Division of Respiratory Medicine, University of British Columbia, VancouverBC, Canada
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