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Boucher MJ, Madhani HD. Convergent evolution of innate immune-modulating effectors in invasive fungal pathogens. Trends Microbiol 2024; 32:435-447. [PMID: 37985333 DOI: 10.1016/j.tim.2023.10.011] [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] [Received: 09/29/2023] [Revised: 10/26/2023] [Accepted: 10/27/2023] [Indexed: 11/22/2023]
Abstract
Invasive fungal infections pose a major threat to human health. Bacterial and protozoan pathogens secrete protein effectors that overcome innate immune barriers to promote microbial colonization, yet few such molecules have been identified in human fungal pathogens. Recent studies have begun to reveal these long-sought effectors and have illuminated how they subvert key cellular pathways, including apoptosis, myeloid cell polarization, Toll-like receptor signaling, and phagosome action. Thus, despite lacking the specialized secretion systems of bacteria and parasites, it is increasingly clear that fungi independently evolved effectors targeting pathways often subverted by other classes of pathogens. These findings demonstrate the remarkable power of convergent evolution to enable diverse microbes to infect humans while also setting the stage for detailed dissection of fungal disease mechanisms.
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Affiliation(s)
- Michael J Boucher
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA
| | - Hiten D Madhani
- Department of Biochemistry & Biophysics, University of California, San Francisco, San Francisco, CA 94158, USA.
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2
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Gonçalves SM, Pereira I, Feys S, Cunha C, Chamilos G, Hoenigl M, Wauters J, van de Veerdonk FL, Carvalho A. Integrating genetic and immune factors to uncover pathogenetic mechanisms of viral-associated pulmonary aspergillosis. mBio 2024:e0198223. [PMID: 38651925 DOI: 10.1128/mbio.01982-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2024] Open
Abstract
Invasive pulmonary aspergillosis is a severe fungal infection primarily affecting immunocompromised patients. Individuals with severe viral infections have recently been identified as vulnerable to developing invasive fungal infections. Both influenza-associated pulmonary aspergillosis (IAPA) and COVID-19-associated pulmonary aspergillosis (CAPA) are linked to high mortality rates, emphasizing the urgent need for an improved understanding of disease pathogenesis to unveil new molecular targets with diagnostic and therapeutic potential. The recent establishment of animal models replicating the co-infection context has offered crucial insights into the mechanisms that underlie susceptibility to disease. However, the development and progression of human viral-fungal co-infections exhibit a significant degree of interindividual variability, even among patients with similar clinical conditions. This observation implies a significant role for host genetics, but information regarding the genetic basis for viral-fungal co-infections is currently limited. In this review, we discuss how genetic factors known to affect either antiviral or antifungal immunity could potentially reveal pathogenetic mechanisms that predispose to IAPA or CAPA and influence the overall disease course. These insights are anticipated to foster further research in both pre-clinical models and human patients, aiming to elucidate the complex pathophysiology of viral-associated pulmonary aspergillosis and contributing to the identification of new diagnostic and therapeutic targets to improve the management of these co-infections.
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Affiliation(s)
- Samuel M Gonçalves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - Inês Pereira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - Simon Feys
- Medical Intensive Care Unit, Department of General Internal Medicine, University Hospitals Leuven, Leuven, Belgium
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
| | - Cristina Cunha
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Guimarães/Braga, Portugal
| | - Georgios Chamilos
- Laboratory of Clinical Microbiology and Microbial Pathogenesis, School of Medicine, University of Crete, Heraklion, Crete, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology, Heraklion, Crete, Greece
| | - Martin Hoenigl
- Division of Infectious Diseases, ECMM Excellence Center for Medical Mycology, Department of Internal Medicine, Medical University of Graz, Graz, Austria
- BioTechMed, Graz, Austria
| | - Joost Wauters
- Medical Intensive Care Unit, Department of General Internal Medicine, University Hospitals Leuven, Leuven, Belgium
- Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
| | - Frank L van de Veerdonk
- Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
- Radboud Center for Infectious Diseases (RCI), Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
| | - Agostinho Carvalho
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Braga, Portugal
- ICVS/3B's-PT Government Associate Laboratory, Guimarães/Braga, Portugal
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Sonnberger J, Kasper L, Lange T, Brunke S, Hube B. "We've got to get out"-Strategies of human pathogenic fungi to escape from phagocytes. Mol Microbiol 2024; 121:341-358. [PMID: 37800630 DOI: 10.1111/mmi.15149] [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] [Received: 06/30/2023] [Revised: 08/08/2023] [Accepted: 08/16/2023] [Indexed: 10/07/2023]
Abstract
Human fungal pathogens are a deadly and underappreciated risk to global health that most severely affect immunocompromised individuals. A virulence attribute shared by some of the most clinically relevant fungal species is their ability to survive inside macrophages and escape from these immune cells. In this review, we discuss the mechanisms behind intracellular survival and elaborate how escape is mediated by lytic and non-lytic pathways as well as strategies to induce programmed host cell death. We also discuss persistence as an alternative to rapid host cell exit. In the end, we address the consequences of fungal escape for the host immune response and provide future perspectives for research and development of targeted therapies.
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Affiliation(s)
- Johannes Sonnberger
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Theresa Lange
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
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Tanner CD, Rosowski EE. Macrophages inhibit extracellular hyphal growth of A. fumigatus through Rac2 GTPase signaling. Infect Immun 2024; 92:e0038023. [PMID: 38168666 PMCID: PMC10863406 DOI: 10.1128/iai.00380-23] [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] [Received: 09/19/2023] [Accepted: 11/27/2023] [Indexed: 01/05/2024] Open
Abstract
Macrophages act as a first line of defense against pathogens. Against Aspergillus fumigatus, a fungus with pathogenic potential in immunocompromised patients, macrophages can phagocytose fungal spores and inhibit spore germination to prevent the development of tissue-invasive hyphae. However, the cellular pathways that macrophages use to accomplish these tasks and any roles macrophages have later in infection against invasive forms of fungi are still not fully known. Rac-family Rho GTPases are signaling hubs for multiple cellular functions in leukocytes, including cell migration, phagocytosis, reactive oxygen species (ROS) generation, and transcriptional activation. We therefore aimed to further characterize the function of macrophages against A. fumigatus in an in vivo vertebrate infection model by live imaging of the macrophage behavior in A. fumigatus-infected rac2 mutant zebrafish larvae. While Rac2-deficient zebrafish larvae are susceptible to A. fumigatus infection, Rac2 deficiency does not impair macrophage migration to the infection site, interaction with and phagocytosis of spores, spore trafficking to acidified compartments, or spore killing. However, we reveal a role for Rac2 in macrophage-mediated inhibition of spore germination and control of invasive hyphae. Re-expression of Rac2 under a macrophage-specific promoter rescues the survival of A. fumigatus-infected rac2 mutant larvae through increased control of germination and hyphal growth. Altogether, we describe a new role for macrophages against extracellular hyphal growth of A. fumigatus and report that the function of the Rac2 Rho GTPase in macrophages is required for this function.
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Affiliation(s)
- Christopher D. Tanner
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA
| | - Emily E. Rosowski
- Department of Biological Sciences, Clemson University, Clemson, South Carolina, USA
- Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, South Carolina, USA
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Goldman G, Valero C, Pinzan C, de Castro P, van Rhijn N, Earle K, Liu H, Horta MA, Kniemeyer O, Kruger T, Pschibul A, Coemert D, Heinekamp T, Brakhage A, Steenwyk J, Mead M, Rokas A, Filler S, da Rosa-Garzon N, Delbaje E, Bromley M, Angeli C, Palmisano G, Ibrahim A, Gago S, Does Reis T. A phylogenetic approach to explore the Aspergillus fumigatus conidial surface-associated proteome and its role in pathogenesis. RESEARCH SQUARE 2023:rs.3.rs-3306535. [PMID: 37790311 PMCID: PMC10543367 DOI: 10.21203/rs.3.rs-3306535/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
Aspergillus fumigatus, an important pulmonary fungal pathogen causing several diseases collectively called aspergillosis, relies on asexual spores (conidia) for initiating host infection. Here, we used a phylogenomic approach to compare proteins in the conidial surface of A. fumigatus, two closely related non-pathogenic species, Aspergillus fischeri and Aspergillus oerlinghausenensis, and the cryptic pathogen Aspergillus lentulus. After identifying 62 proteins uniquely expressed on the A. fumigatus conidial surface, we assessed null mutants for 42 genes encoding conidial proteins. Deletion of 33 of these genes altered susceptibility to macrophage killing, penetration and damage to epithelial cells, and cytokine production. Notably, a gene that encodes glycosylasparaginase, which modulates levels of the host pro-inflammatory cytokine IL-1β, is important for infection in an immunocompetent murine model of fungal disease. These results suggest that A. fumigatus conidial surface proteins and effectors are important for evasion and modulation of the immune response at the onset of fungal infection.
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Affiliation(s)
- Gustavo Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Bloco Q, Universidade de São Paulo
| | | | - Camila Pinzan
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Bloco Q, Universidade de São Paulo
| | - Patrícia de Castro
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, São Paulo
| | | | - Kayleigh Earle
- Manchester Fungal Infection Group, Division of Evolution, Infection, and Genomics, Faculty of Biology, Medicine and Health, University of Manchester
| | - Hong Liu
- The Lundquist Institute for Biomedical Innovation
| | | | - Olaf Kniemeyer
- Leibniz Institute for Natural Product Research and Infection Biology (HKI)
| | | | - Annica Pschibul
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI) and Institute of Microbiology, Friedrich Schiller University
| | - Derya Coemert
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI) and Institute of Microbiology, Friedrich Schiller University
| | - Thorsten Heinekamp
- Department of Molecular and Applied Microbiology, Leibniz Institute for Natural Product Research and Infection Biology (Leibniz-HKI) and Institute of Microbiology, Friedrich Schiller University
| | | | | | | | | | - Scott Filler
- Division of Infectious Diseases, Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center
| | | | | | | | | | | | - Ashraf Ibrahim
- The Lundquist Institute at Harbor-University of California Los Angeles Medical Center
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Stuckey PV, Santiago-Tirado FH. Fungal mechanisms of intracellular survival: what can we learn from bacterial pathogens? Infect Immun 2023; 91:e0043422. [PMID: 37506189 PMCID: PMC10501222 DOI: 10.1128/iai.00434-22] [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] [Received: 11/28/2022] [Accepted: 06/23/2023] [Indexed: 07/30/2023] Open
Abstract
Fungal infections represent a major, albeit neglected, public health threat with serious medical and economic burdens globally. With unacceptably high mortality rates, invasive fungal pathogens are responsible for millions of deaths each year, with a steadily increasing incidence primarily in immunocompromised individuals. The poor therapeutic options and rise of antifungal drug resistance pose further challenges in controlling these infections. These fungal pathogens have adapted to survive within mammalian hosts and can establish intracellular niches to promote survival within host immune cells. To do that, they have developed diverse methods to circumvent the innate immune system attack. This includes strategies such as altering their morphology, counteracting macrophage antimicrobial action, and metabolic adaptation. This is reminiscent of how bacterial pathogens have adapted to survive within host cells and cause disease. However, relative to the great deal of information available concerning intracellular bacterial pathogenesis, less is known about the mechanisms fungal pathogens employ. Therefore, here we review our current knowledge and recent advances in our understanding of how fungi can evade and persist within host immune cells. This review will focus on the major fungal pathogens, including Cryptococcus neoformans, Candida albicans, and Aspergillus fumigatus, among others. As we discover and understand the strategies used by these fungi, similarities with their bacterial counterparts are becoming apparent, hence we can use the abundant information from bacteria to guide our studies in fungi. By understanding these strategies, new lines of research will open that can improve the treatments of these devastating fungal diseases.
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Affiliation(s)
- Peter V. Stuckey
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
| | - Felipe H. Santiago-Tirado
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana, USA
- Eck Institute for Global Health, University of Notre Dame, Notre Dame, Indiana, USA
- Warren Center for Drug Discovery, University of Notre Dame, Notre Dame, Indiana, USA
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Valero C, Pinzan CF, de Castro PA, van Rhijn N, Earle K, Liu H, Horta MAC, Kniemeyer O, Krüger T, Pschibul A, Coemert DN, Heinekamp T, Brakhage AA, Steenwyk JL, Mead ME, Rokas A, Filler SG, da Rosa-Garzon NG, Cabral H, Deljabe E, Bromley MJ, Angeli CB, Palmisano G, Ibrahim AS, Gago S, Dos Reis TF, Goldman GH. A phylogenetic approach to explore the Aspergillus fumigatus conidial surface-associated proteome and its role in pathogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.553365. [PMID: 37662192 PMCID: PMC10473670 DOI: 10.1101/2023.08.22.553365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Aspergillus fumigatus , an important pulmonary fungal pathogen causing several diseases collectively called aspergillosis, relies on asexual spores or conidia for initiating host infection. Here, we used a phylogenomic approach to compare proteins in the conidial surface of A. fumigatus , two closely related non-pathogenic species, Aspergillus fischeri and Aspergillus oerlinghausenensis , and the cryptic pathogen Aspergillus lentulus . After identifying 62 proteins uniquely expressed on the A. fumigatus conidial surface, we deleted 42 genes encoding conidial proteins. We found deletion of 33 of these genes altered susceptibility to macrophage killing, penetration and damage to epithelial cells, and cytokine production. Notably, a gene that encodes glycosylasparaginase, which modulates levels of the host pro-inflammatory cytokine IL-1β, is important for infection in an immunocompetent murine model of fungal disease. These results suggest that A. fumigatus conidial surface proteins and effectors are important for evasion and modulation of the immune response at the onset of fungal infection.
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Camacho E, Coelho C. Getaway car: Fungal HscA steers human phagosomal p11 into an escape route. Cell Host Microbe 2023; 31:324-327. [PMID: 36893729 DOI: 10.1016/j.chom.2023.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023]
Abstract
In this issue of Cell Host & Microbe, Jia and colleagues discover how the human p11 (s100A10)-Anxa2 heterodimer drives sorting of microbial phagosomes into recycling versus degradative pathways. In a remarkable evolutionary arms race, the Aspergillus fumigatus protein HscA latches to p11 to steer its phagosome away from fungal killing.
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Affiliation(s)
- Emma Camacho
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, The Johns Hopkins Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Carolina Coelho
- MRC Centre for Medical Mycology at University of Exeter, Exeter, EX4 4QD Devon, UK.
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