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Gandhi P, Hebert B, Yun A, Bradley J, Moldoveanu B. Histoplasmosis around the world: A global perspective on the presentation, virulence factors, and treatment of histoplasmosis. Am J Med Sci 2024; 368:287-299. [PMID: 38885929 DOI: 10.1016/j.amjms.2024.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 04/29/2024] [Accepted: 06/12/2024] [Indexed: 06/20/2024]
Abstract
Histoplasmosis is a systemic infection caused by an endemic dimorphic fungus, Histoplasma capsulatum. Though prevalent in the eastern United States of America, near the Ohio and Mississippi River Valleys, the evidence underlying the global prevalence of histoplasmosis, especially in immunocompromised populations, is underappreciated. This article highlights the global epidemiology, risk factors, microbiology and pathophysiological characteristics, pulmonary and extrapulmonary manifestations, prevention measures, radiographic patterns, diagnostic techniques, and antifungal treatment approaches for Histoplasma capsulatum.
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Affiliation(s)
- Pooja Gandhi
- Division of General Internal Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Brandon Hebert
- Division of General Internal Medicine, University of Louisville, Louisville, Kentucky, USA
| | - Angelica Yun
- Division of General Internal Medicine, University of Louisville, Louisville, Kentucky, USA
| | - James Bradley
- Division of Pulmonary, Critical Care Medicine, and Sleep Disorders, University of Louisville, Louisville, Kentucky, USA.
| | - Bogdan Moldoveanu
- Division of Pulmonary, Critical Care Medicine, and Sleep Disorders, University of Louisville, Louisville, Kentucky, USA
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2
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Santos LA, Castro Dutra J, Malaquias LCC, Andrade ND, Gomes BN, Burger E. Paracoccidioides spp.: Escape mechanisms and their implications for the development of this mycosis. Microb Pathog 2024; 196:106951. [PMID: 39299555 DOI: 10.1016/j.micpath.2024.106951] [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: 05/28/2024] [Revised: 09/13/2024] [Accepted: 09/15/2024] [Indexed: 09/22/2024]
Abstract
Paracoccidioidomycosis (PCM) is a systemic granulomatous mycosis prevalent in individuals who carry out rural activities. Its etiological agent is a thermodimorphic fungus belonging to the genus; Paracoccidioides spp. Seven species of this fungus are known: Paracoccidioides brasiliensis, Paracoccidioides lutzii, Paracoccidioides americana, Paracoccidioides restrepiensis, Paracoccidioides venezuelensis, Paracoccidioides loboi and Paracoccidioides ceti. For a long time, Paracoccidioides brasiliensis was attributed as the only causal agent of this mycosis. What is known about adhesins, virulence, escape mechanisms and fungal involvement with the host's immune system is correlated with the species Paracoccidioides brasiliensis. Interactions between Paracoccidioides spp. and the host are complex and dynamic. The fungus needs nutrients for its needs and must adapt to a hostile environment, evading the host's immune system, thus enabling the development of the infectious process. On the other hand, the host's immune system recognizes Paracoccidioides spp. and employs all protective mechanisms to prevent fungal growth and consequently tissue invasion. Knowing this, understanding how Paracoccidioides spp. escapes the host's immune system, can help to understand the pathogenic mechanisms related to the development of the disease and, therefore, in the design of new specific treatment strategies. In this review we discuss these mechanisms and what are the adhesion molecules of Paracoccidioides spp. uses to escape the hostile environment imposed by the host's defense mechanisms; finally, we suggest how to neutralize them with new antifungal therapies.
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Affiliation(s)
- Lauana Aparecida Santos
- Department of Microbiology and Immunology at Federal University of Alfenas - UNIFAL, Alfenas, MG, CEP 37130-001, Brazil
| | - Julia Castro Dutra
- Department of Microbiology and Immunology at Federal University of Alfenas - UNIFAL, Alfenas, MG, CEP 37130-001, Brazil
| | - Luiz Cosme Cotta Malaquias
- Department of Microbiology and Immunology at Federal University of Alfenas - UNIFAL, Alfenas, MG, CEP 37130-001, Brazil
| | - Nayara Dias Andrade
- Department of Microbiology and Immunology at Federal University of Alfenas - UNIFAL, Alfenas, MG, CEP 37130-001, Brazil
| | - Bruno Nascimento Gomes
- Department of Microbiology and Immunology at Federal University of Alfenas - UNIFAL, Alfenas, MG, CEP 37130-001, Brazil
| | - Eva Burger
- Department of Microbiology and Immunology at Federal University of Alfenas - UNIFAL, Alfenas, MG, CEP 37130-001, Brazil.
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3
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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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Puerta-Arias JD, Isaza Agudelo JP, Naranjo Preciado TW. Identification and production of novel potential pathogen-specific biomarkers for diagnosis of histoplasmosis. Microbiol Spectr 2023; 11:e0093923. [PMID: 37882565 PMCID: PMC10714873 DOI: 10.1128/spectrum.00939-23] [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: 03/03/2023] [Accepted: 09/08/2023] [Indexed: 10/27/2023] Open
Abstract
IMPORTANCE Histoplasmosis is considered one of the most important mycoses due to the increasing number of individuals susceptible to develop severe clinical forms, particularly those with HIV/AIDS or receiving immunosuppressive biological therapies, the high mortality rates reported when antifungal treatment is not initiated in a timely manner, and the limitations of conventional diagnostic methods. In this context, there is a clear need to improve the capacity of diagnostic tools to specifically detect the fungal pathogen, regardless of the patient's clinical condition or the presence of other co-infections. The proposed novel pathogen-specific biomarkers have the potential to be used in immunodiagnostic platforms and antifungal treatment monitoring in histoplasmosis. In addition, the bioinformatics strategy used in this study could be applied to identify potential diagnostic biomarkers in other models of fungal infection of public health importance.
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Affiliation(s)
- Juan David Puerta-Arias
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB-UdeA-UPB-UDES), Medellín, Colombia
- School of Health Sciences, Universidad Pontificia Bolivariana, Medellín, Colombia
- Universidad de Santander (UDES), Facultad de Ciencias Médicas y de la Salud, Bucaramanga, Colombia
| | | | - Tonny Williams Naranjo Preciado
- Medical and Experimental Mycology Group, Corporación para Investigaciones Biológicas (CIB-UdeA-UPB-UDES), Medellín, Colombia
- School of Health Sciences, Universidad Pontificia Bolivariana, Medellín, Colombia
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5
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Miramón P, Pountain AW, Lorenz MC. Candida auris-macrophage cellular interactions and transcriptional response. Infect Immun 2023; 91:e0027423. [PMID: 37815367 PMCID: PMC10652981 DOI: 10.1128/iai.00274-23] [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: 07/14/2023] [Accepted: 08/29/2023] [Indexed: 10/11/2023] Open
Abstract
The pathogenic yeast Candida auris represents a global threat of the utmost clinical relevance. This emerging fungal species is remarkable in its resistance to commonly used antifungal agents and its persistence in the nosocomial settings. The innate immune system is one the first lines of defense preventing the dissemination of pathogens in the host. C. auris is susceptible to circulating phagocytes, and understanding the molecular details of these interactions may suggest routes to improved therapies. In this work, we examined the interactions of this yeast with macrophages. We found that macrophages avidly phagocytose C. auris; however, intracellular replication is not inhibited, indicating that C. auris resists the killing mechanisms imposed by the phagocyte. Unlike Candida albicans, phagocytosis of C. auris does not induce macrophage lysis. The transcriptional response of C. auris to macrophage phagocytosis is very similar to other members of the CUG clade (C. albicans, C. tropicalis, C. parapsilosis, C. lusitaniae), i.e., downregulation of transcription/translation and upregulation of alternative carbon metabolism pathways, transporters, and induction of oxidative stress response and proteolysis. Gene family expansions are common in this yeast, and we found that many of these genes are induced in response to macrophage co-incubation. Among these, amino acid and oligopeptide transporters, as well as lipases and proteases, are upregulated. Thus, C. auris shares key transcriptional signatures shared with other fungal pathogens and capitalizes on the expansion of gene families coding for potential virulence attributes that allow its survival, persistence, and evasion of the innate immune system.
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Affiliation(s)
- Pedro Miramón
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, USA
| | | | - Michael C. Lorenz
- Department of Microbiology and Molecular Genetics, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, USA
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Lange T, Kasper L, Gresnigt MS, Brunke S, Hube B. "Under Pressure" - How fungi evade, exploit, and modulate cells of the innate immune system. Semin Immunol 2023; 66:101738. [PMID: 36878023 PMCID: PMC10109127 DOI: 10.1016/j.smim.2023.101738] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Indexed: 03/06/2023]
Abstract
The human immune system uses an arsenal of effector mechanisms to prevent and counteract infections. Yet, some fungal species are extremely successful as human pathogens, which can be attributed to a wide variety of strategies by which these fungi evade, exploit, and modulate the immune system. These fungal pathogens normally are either harmless commensals or environmental fungi. In this review we discuss how commensalism, but also life in an environmental niche without human contact, can drive the evolution of diverse and specialized immune evasion mechanisms. Correspondingly, we discuss the mechanisms contributing to the ability of these fungi to cause superficial to life-threatening infections.
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Affiliation(s)
- Theresa Lange
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, Jena, Germany
| | - Mark S Gresnigt
- Junior Research Group Adaptive Pathogenicity Strategies, 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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Valdez AF, Miranda DZ, Guimarães AJ, Nimrichter L, Nosanchuk JD. Pathogenicity & Virulence of Histoplasma capsulatum - a multifaceted organism adapted to intracellular environments. Virulence 2022; 13:1900-1919. [PMID: 36266777 DOI: 10.1080/21505594.2022.2137987] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Histoplasmosis is a systemic mycosis caused by the thermally dimorphic fungus Histoplasma capsulatum. Although healthy individuals can develop histoplasmosis, the disease is particularly life-threatening in immunocompromised patients, with a wide range of clinical manifestations depending on the inoculum and virulence of the infecting strain. In this review, we discuss the established virulence factors and pathogenesis traits that make H. capsulatum highly adapted to a wide variety of hosts, including mammals. Understanding and integrating these mechanisms is a key step towards devising new preventative and therapeutic interventions.
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Affiliation(s)
- Alessandro F Valdez
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Geral, Rio de Janeiro, Brazil
| | - Daniel Zamith Miranda
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
| | - Allan Jefferson Guimarães
- Universidade Federal Fluminense, Instituto Biomédico, Departamento de Microbiologia e Parasitologia - MIP, Niterói, Rio de Janeiro, Brazil
| | - Leonardo Nimrichter
- Universidade Federal do Rio de Janeiro, Instituto de Microbiologia Paulo de Góes, Departamento de Microbiologia Geral, Rio de Janeiro, Brazil
| | - Joshua D Nosanchuk
- Departments of Medicine (Division of Infectious Diseases) and Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York, USA
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8
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Coccidioides Species: A Review of Basic Research: 2022. J Fungi (Basel) 2022; 8:jof8080859. [PMID: 36012847 PMCID: PMC9409882 DOI: 10.3390/jof8080859] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/04/2022] [Accepted: 08/09/2022] [Indexed: 11/17/2022] Open
Abstract
Coccidioides immitis and posadasii are closely related fungal species that cause coccidioidomycosis. These dimorphic organisms cause disease in immunocompetent as well as immunocompromised individuals and as much as 40% of the population is infected in the endemic area. Although most infections resolve spontaneously, the infection can be prolonged and, in some instances, fatal. Coccidioides has been studied for more than 100 years and many aspects of the organism and the disease it causes have been investigated. There are over 500 manuscripts concerning Coccidioides (excluding clinical articles) referenced in PubMed over the past 50 years, so there is a large body of evidence to review. We reviewed the most accurate and informative basic research studies of these fungi including some seminal older studies as well as an extensive review of current research. This is an attempt to gather the most important basic research studies about this fungus into one publication. To focus this review, we will discuss the mycology of the organism exclusively rather than the studies of the host response or clinical studies. We hope that this review will be a useful resource to those interested in Coccidioides and coccidioidomycosis.
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Chen J, Han S, Li S, Wang M, Zhu H, Qiao T, Lin T, Zhu T. Comparative Transcriptomics and Gene Knockout Reveal Virulence Factors of Neofusicoccum parvum in Walnut. Front Microbiol 2022; 13:926620. [PMID: 35910616 PMCID: PMC9335079 DOI: 10.3389/fmicb.2022.926620] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Accepted: 06/17/2022] [Indexed: 12/11/2022] Open
Abstract
Neofusicoccum parvum can cause stem and branch blight of walnut (Juglans spp.), resulting in great economic losses and ecological damage. A total of two strains of N. parvum were subjected to RNA-sequencing after being fed on different substrates, sterile water (K1/K2), and walnut (T1/T2), and the function of ABC1 was verified by gene knockout. There were 1,834, 338, and 878 differentially expressed genes (DEGs) between the K1 vs. K2, T1 vs. K1, and T2 vs. K2 comparison groups, respectively. The expression changes in thirty DEGs were verified by fluorescent quantitative PCR. These thirty DEGs showed the same expression patterns under both RNA-seq and PCR. In addition, ΔNpABC1 showed weaker virulence due to gene knockout, and the complementary strain NpABC1c showed the same virulence as the wild-type strain. Compared to the wild-type and complemented strains, the relative growth of ΔNpABC1 was significantly decreased when grown with H2O2, NaCl, Congo red, chloramphenicol, MnSO4, and CuSO4. The disease index of walnuts infected by the mutants was significantly lower than those infected by the wild-type and complementary strains. This result indicates that ABC1 gene is required for the stress response and virulence of N. parvum and may be involved in heavy metal resistance.
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Affiliation(s)
- Jie Chen
- Department of Forest Protection, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Shan Han
- Department of Forest Protection, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Shujiang Li
- Department of Forest Protection, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Ming Wang
- Ecological Institute, Academy of Sichuan Forestry and Grassland Inventory and Planning, Chengdu, China
| | - Hanmingyue Zhu
- Department of Forest Protection, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Tianmin Qiao
- Department of Forest Protection, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Tiantian Lin
- Department of Forest Protection, College of Forestry, Sichuan Agricultural University, Chengdu, China
| | - Tianhui Zhu
- Department of Forest Protection, College of Forestry, Sichuan Agricultural University, Chengdu, China
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Macrophages in Microbial Pathogenesis: Commonalities of Defense Evasion Mechanisms. Infect Immun 2021; 90:e0029121. [PMID: 34780281 DOI: 10.1128/iai.00291-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Macrophages are key arsenals of the immune system against invaders. After compartmental isolation of a pathogen in phagosomes, the host immune response attempts to neutralize the pathogen. However, pathogens possess the ability to subvert these assaults and can also convert macrophages into their replicative niche. The multiple host defense evasion mechanisms employed by these pathogens like phagosome maturation arrest, molecular mimicry through secretory antigens, interference with host signaling, active radical neutralization, inhibition of phagosome acidification, alteration of programmed cell death and many other mechanisms. Macrophage biology as a part of the host-pathogen interaction has expanded rapidly in the past decade. The present review aims to shed some light upon the macrophage defense evasion strategies employed by infecting pathogens. We have also incorporated recent knowledge in the field of macrophage dynamics during infection and evolutionary perspectives of macrophage dynamics.
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11
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Rana A, Gupta N, Thakur A. Post-transcriptional and translational control of the morphology and virulence in human fungal pathogens. Mol Aspects Med 2021; 81:101017. [PMID: 34497025 DOI: 10.1016/j.mam.2021.101017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 08/13/2021] [Accepted: 08/20/2021] [Indexed: 11/17/2022]
Abstract
Host-pathogen interactions at the molecular level are the key to fungal pathogenesis. Fungal pathogens utilize several mechanisms such as adhesion, invasion, phenotype switching and metabolic adaptations, to survive in the host environment and respond. Post-transcriptional and translational regulations have emerged as key regulatory mechanisms ensuring the virulence and survival of fungal pathogens. Through these regulations, fungal pathogens effectively alter their protein pool, respond to various stress, and undergo morphogenesis, leading to efficient and comprehensive changes in fungal physiology. The regulation of virulence through post-transcriptional and translational regulatory mechanisms is mediated through mRNA elements (cis factors) or effector molecules (trans factors). The untranslated regions upstream and downstream of the mRNA, as well as various RNA-binding proteins involved in translation initiation or circularization of the mRNA, play pivotal roles in the regulation of morphology and virulence by influencing protein synthesis, protein isoforms, and mRNA stability. Therefore, post-transcriptional and translational mechanisms regulating the morphology, virulence and drug-resistance processes in fungal pathogens can be the target for new therapeutics. With improved "omics" technologies, these regulatory mechanisms are increasingly coming to the forefront of basic biology and drug discovery. This review aims to discuss various modes of post-transcriptional and translation regulations, and how these mechanisms exert influence in the virulence and morphogenesis of fungal pathogens.
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Affiliation(s)
- Aishwarya Rana
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India
| | - Nidhi Gupta
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India
| | - Anil Thakur
- Regional Centre for Biotechnology, 3rd Milestone Gurgaon-Faridabad Expressway, Faridabad 121001, India.
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12
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Transcription in fungal conidia before dormancy produces phenotypically variable conidia that maximize survival in different environments. Nat Microbiol 2021; 6:1066-1081. [PMID: 34183813 DOI: 10.1038/s41564-021-00922-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 05/18/2021] [Indexed: 02/05/2023]
Abstract
Fungi produce millions of clonal asexual conidia (spores) that remain dormant until favourable conditions occur. Conidia contain abundant stable messenger RNAs but the mechanisms underlying the production of these transcripts and their composition and functions are unknown. Here, we report that the conidia of three filamentous fungal species (Aspergillus nidulans, Aspergillus fumigatus, Talaromyces marneffei) are transcriptionally active and can synthesize mRNAs. We find that transcription in fully developed conidia is modulated in response to changes in the environment until conidia leave the developmental structure. Environment-specific transcriptional responses can alter conidial content (mRNAs, proteins and secondary metabolites) and change gene expression when dormancy is broken. Conidial transcription affects the fitness and capabilities of fungal cells after germination, including stress and antifungal drug (azole) resistance, mycotoxin and secondary metabolite production and virulence. The transcriptional variation that we characterize in fungal conidia explains how genetically identical conidia mature into phenotypically variable conidia. We find that fungal conidia prepare for the future by synthesizing and storing transcripts according to environmental conditions present before dormancy.
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13
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Kijpornyongpan T, Aime MC. Comparative transcriptomics reveal different mechanisms for hyphal growth across four plant-associated dimorphic fungi. Fungal Genet Biol 2021; 152:103565. [PMID: 33991665 DOI: 10.1016/j.fgb.2021.103565] [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: 09/24/2020] [Revised: 03/07/2021] [Accepted: 05/03/2021] [Indexed: 11/27/2022]
Abstract
Fungal dimorphism is a phenomenon by which a fungus can grow both as a yeast form and a hyphal form. It is frequently related to pathogenicity as different growth forms are more suitable for different functions during a life cycle. Among dimorphic plant pathogens, the corn smut fungus Ustilago maydis serves as a model organism to understand fungal dimorphism and its effect on pathogenicity. However, there is a lack of data on whether mechanisms elucidated from model species are broadly applicable to other fungi. In this study, two non-model plant-associated species in the smut fungus subphylum (Ustilaginomycotina), Tilletiopsis washingtonensis and Meira miltonrushii, were selected to compare dimorphic mechanisms in these to those in U. maydis. We sequenced transcriptomic profiles during both yeast and hyphal growth in these two species using Tween40, a lipid mimic, as a trigger for hyphal growth. We then compared our data with previously published data from U. maydis and a fourth but unrelated dimorphic phytopathogen, Ophiostoma novo-ulmi. Comparative transcriptomics was performed to identify common genes upregulated during hyphal growth in all four dimorphic species. Intriguingly, T. washingtonensis shares the least similarities of transcriptomic alteration (hyphal growth versus yeast growth) with the others, although it is closely related to M. miltonrushii and U. maydis. This suggests that phylogenetic relatedness is not correlated with transcriptomic similarity under the same biological phenomenon. Among commonly expressed genes in the four species, genes in cell energy production and conversion, amino acid transport and metabolism and cytoskeleton are significantly enriched. Considering dimorphism genes characterized in U. maydis, as well as hyphal tip-associated genes from the literature, we found only genes encoding the cell end marker Tea4/TeaC and the kinesin motor protein Kin3 concordantly expressed in all four species. This suggests a divergence in species-specific mechanisms for dimorphic transition and hyphal growth.
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Affiliation(s)
- Teeratas Kijpornyongpan
- Department of Botany and Plant Pathology, Purdue University, 915 W State St, West Lafayette, IN 47907-2054, USA
| | - M Catherine Aime
- Department of Botany and Plant Pathology, Purdue University, 915 W State St, West Lafayette, IN 47907-2054, USA.
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14
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Kawali A, Mahendradas P, Sanjay S, K M P, Yadav J, Panchagnula R, K S S. Diagnostic and Therapeutic Challenges in Ocular Histoplasmosis - A Case Report. Ocul Immunol Inflamm 2020; 30:149-152. [PMID: 32931351 DOI: 10.1080/09273948.2020.1797114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Purpose: To report a rare case of skin biopsy proven Histoplasma panuveitis.Method: Observational case report of a 76-year-old Asian Indian man presented as panuveitis. Clinical course, diagnostic and treatment difficulties and confocal microscopy findings were studied.Result: Patient presented with mild anterior uveitis, membranous vitritis and large chorio-retinal lesions in peripheral fundus with a small macular scar in the right eye. Positive quantiferon test along with chest and adrenal findings initially misled ophthalmologist and pulmonologist to commence anti-tubercular treatment with steroids which further worsened the inflammation and the fungus involved iris and scleral tissue. Skin biopsy from the lesions on thigh revealed histoplasma spores and confocal microscopy showed similar cystic lesions on endothelium. Prolonged course of anti-fungal with steroids resulted in resolution of the infection.Conclusion: Histoplasma uveitis can worsen with steroids only treatment and may invade iris and scleral tissue which may require prolonged treatment with antifungal agents.
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Affiliation(s)
- Ankush Kawali
- Department of Uveitis and Ocular Immunology, Narayana Nethralaya, Bangalore, India
| | | | - Srinivasan Sanjay
- Department of Uveitis and Ocular Immunology, Narayana Nethralaya, Bangalore, India
| | - Prathima K M
- Department of Pathology, Vikram Hospital, Bangalore, India
| | - Jaydev Yadav
- Department of Dermatology, Vikram Hospital, Bangalore, India
| | | | - Sathish K S
- Department of Pulmonology, Vikram Hospital, Bangalore, India
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15
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Abstract
Histoplasma capsulatum is a member of a group of fungal pathogens called thermally dimorphic fungi, all of which respond to mammalian body temperature by converting from an environmental mold form into a parasitic host form that causes disease. Histoplasma is a primary fungal pathogen, meaning it is able to cause disease in healthy individuals. We are beginning to understand how host temperature is utilized as a key signal to facilitate growth in the parasitic yeast form and promote production of virulence factors. In recent years, multiple regulators of morphology and virulence have been identified in Histoplasma. Mutations in these regulators render the pathogen unable to convert to the parasitic yeast form. Additionally, several virulence factors have been characterized for their importance in in vivo survival and pathogenesis. These virulence factors and regulators can serve as molecular handles for the development of effective drugs and therapeutics to counter Histoplasma infection.
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Affiliation(s)
- Sinem Beyhan
- Department of Infectious Diseases, J. Craig Venter Institute , La Jolla , CA , USA
| | - Anita Sil
- Department of Microbiology and Immunology, University of California , San Francisco , CA , USA
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16
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Elias Moreira AL, Milhomem Cruz-Leite VR, O'Hara Souza Silva L, Alves Parente AF, Bailão AM, Maria de Almeida Soares C, Parente-Rocha JA, Ruiz OH, Borges CL. Proteome characterization of Paracoccidioides lutzii conidia by using nanoUPLC-MS E. Fungal Biol 2020; 124:766-780. [PMID: 32883428 DOI: 10.1016/j.funbio.2020.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Revised: 04/27/2020] [Accepted: 05/22/2020] [Indexed: 12/30/2022]
Abstract
Fungi of the genus Paracoccidioides are the etiological agents of Paracoccidioidomycosis (PCM), the most prevalent mycosis in Latin America. Paracoccidioidomycosis infection is acquired by inhalation of Paracoccidioides conidia, which have first contact with the lungs and can subsequently spread to other organs/tissues. Until now, there have been no proteomic studies focusing on this infectious particle of Paracoccidioides. In order to identify the Paracoccidioides lutzii conidia proteome, conidia were produced and purified. Proteins were characterized by use of the nanoUPLC-MSE approach. The strategy allowed us to identify a total of 242 proteins in P. lutzii conidia. In the conidia proteome, proteins were classified in functional categories such as protein synthesis, energy production, metabolism, cellular defense/virulence processes, as well as other processes that can be important for conidia survival. Through this analysis, a pool of ribosomal proteins was identified, which may be important for the initial processes of dimorphic transition. In addition, molecules related to energetic and metabolic processes were identified, suggesting a possible basal metabolism during this form of resistance of the fungus. In addition, adhesins and virulence factors were identified in the P. lutzii conidia proteome. Our results demonstrate the potential role that these molecules can play during early cell-host interaction processes, as well as the way in which these molecules are involved in environmental survival during this form of propagation.
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Affiliation(s)
- André Luís Elias Moreira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | | | - Lana O'Hara Souza Silva
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | | | - Alexandre Melo Bailão
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Célia Maria de Almeida Soares
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Juliana Alves Parente-Rocha
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Orville Hernandez Ruiz
- Unidad de Biología Celular y Molecular, Corporación para Investigaciones Biológicas (CIB), Medellín, Colombia; Grupo de Investigación MICROBA, Escuela de Microbiología, Universidad de Antioquia, Medellín, Colombia.
| | - Clayton Luiz Borges
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
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17
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Suárez-Álvarez RO, Sahaza JH, Berzunza-Cruz M, Becker I, Curiel-Quesada E, Pérez-Torres A, Reyes-Montes MDR, Taylor ML. Dimorphism and Dissemination of Histoplasma capsulatum in the Upper Respiratory Tract after Intranasal Infection of Bats and Mice with Mycelial Propagules. Am J Trop Med Hyg 2020; 101:716-723. [PMID: 31287042 PMCID: PMC6726946 DOI: 10.4269/ajtmh.18-0788] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
This article describes, for the first time, the role of the nasal mucosa (NM) as the initial site for the Histoplasma capsulatum mycelial-to-yeast transition. The results highlight that yeasts may arrive to the cervical lymph nodes (CLN) via phagocytes. Bats and mice were intranasally infected with H. capsulatum mycelial propagules and they were killed 10, 20, and 40 minutes and 1, 2, and 3 hours after infection. The NM and the CLN were monitored for fungal presence. Yeasts compatible with H. capsulatum were detected within the NM and the CLN dendritic cells (DCs) 2–3 hours postinfection, using immunohistochemistry. Histoplasma capsulatum was re-isolated by culturing at 28°C from the CLN of both mammalian hosts 2–3 hours postinfection. Reverse transcription-polymerase chain reaction assays were designed to identify fungal dimorphism, using mycelial-specific (MS8) and yeast-specific (YPS3) gene expression. This strategy supported fast fungal dimorphism in vivo, which began in the NM 1 hour postinfection (a time point when MS8 and YPS3 genes were expressed) and it was completed at 3 hours (a time point when only the YPS3 transcripts were detected) in both bats and mice. The presence of intracellular yeasts in the nasal-associated lymphoid tissue (NALT), in the NM nonassociated with the NALT, and within the interdigitating DCs of the CLN suggests early fungal dissemination via the lymph vessels.
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Affiliation(s)
- Roberto O Suárez-Álvarez
- Departamento de Micología, Instituto Nacional de Enfermedades Infecciosas- Administración Nacional de Laboratorios e Institutos de Salud "Dr. Carlos G. Malbrán", Buenos Aires, Argentina.,Unidad de Micología, Departamento de Microbiología-Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Jorge H Sahaza
- Unidad de Micología Médica y Experimental, Corporación para Investigaciones Biológicas, Medellín, Colombia.,Unidad de Micología, Departamento de Microbiología-Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Miriam Berzunza-Cruz
- Departamento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Ingeborg Becker
- Departamento de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Everardo Curiel-Quesada
- Departamento de Bioquímica, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad de México, Mexico
| | - Armando Pérez-Torres
- Departamento de Biología Celular y Tisular, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - María Del Rocío Reyes-Montes
- Unidad de Micología, Departamento de Microbiología-Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Maria Lucia Taylor
- Unidad de Micología, Departamento de Microbiología-Parasitología, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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18
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Wu W, Nemri A, Blackman LM, Catanzariti AM, Sperschneider J, Lawrence GJ, Dodds PN, Jones DA, Hardham AR. Flax rust infection transcriptomics reveals a transcriptional profile that may be indicative for rust Avr genes. PLoS One 2019; 14:e0226106. [PMID: 31830116 PMCID: PMC6907798 DOI: 10.1371/journal.pone.0226106] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Accepted: 11/19/2019] [Indexed: 01/04/2023] Open
Abstract
Secreted effectors of fungal pathogens are essential elements for disease development. However, lack of sequence conservation among identified effectors has long been a problem for predicting effector complements in fungi. Here we have explored the expression characteristics of avirulence (Avr) genes and candidate effectors of the flax rust fungus, Melampsora lini. We performed transcriptome sequencing and real-time quantitative PCR (qPCR) on RNA extracted from ungerminated spores, germinated spores, isolated haustoria and flax seedlings inoculated with M. lini isolate CH5 during plant infection. Genes encoding two categories of M. lini proteins, namely Avr proteins and plant cell wall degrading enzymes (CWDEs), were investigated in detail. Analysis of the expression profiles of 623 genes encoding predicted secreted proteins in the M. lini transcriptome shows that the six known Avr genes (i.e. AvrM (avrM), AvrM14, AvrL2, AvrL567, AvrP123 (AvrP) and AvrP4) fall within a group of 64 similarly expressed genes that are induced in planta and show a peak of expression early in infection with a subsequent decline towards sporulation. Other genes within this group include two paralogues of AvrL2, an AvrL567 virulence allele, and a number of genes encoding putative effector proteins. By contrast, M. lini genes encoding CWDEs fall into different expression clusters with their distribution often unrelated to their catalytic activity or substrate targets. These results suggest that synthesis of M. lini Avr proteins may be regulated in a coordinated fashion and that the expression profiling-based analysis has significant predictive power for the identification of candidate Avr genes.
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Affiliation(s)
- Wenjie Wu
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australia
- * E-mail:
| | | | - Leila M. Blackman
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australia
| | - Ann-Maree Catanzariti
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australia
| | - Jana Sperschneider
- Biological Data Science Institute, the Australian National University, Canberra, Australia
| | | | | | - David A. Jones
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australia
| | - Adrienne R. Hardham
- Division of Plant Sciences, Research School of Biology, The Australian National University, Canberra, Australia
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19
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Sil A. Molecular regulation of Histoplasma dimorphism. Curr Opin Microbiol 2019; 52:151-157. [PMID: 31739263 PMCID: PMC6910920 DOI: 10.1016/j.mib.2019.10.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 10/30/2019] [Indexed: 01/06/2023]
Abstract
Temperature serves as a fundamental signal in biological systems. In some microbial pathogens of humans, mammalian body temperature triggers establishment and maintenance of a developmental program that allows the microbe to survive and thrive in the host. Histoplasma capsulatum is one of a group of fungal pathogens called thermally dimorphic fungi, all of which respond to mammalian body temperature by converting from an environmental mold form that inhabits the soil into a parasitic form that causes disease in the host. It has been known for decades that temperature is a key signal that is sufficient to trigger the switch from the soil to host form (and vice versa) in the laboratory. Recent molecular studies have identified a number of key regulators that are required to specify each of the developmental forms in response to temperature. Here we review the regulatory circuits that govern temperature-dependent dimorphism in Histoplasma.
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Affiliation(s)
- Anita Sil
- Department of Microbiology & Immunology, University of California San Francisco, San Francisco, CA 94143, USA.
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20
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Rodriguez L, Voorhies M, Gilmore S, Beyhan S, Myint A, Sil A. Opposing signaling pathways regulate morphology in response to temperature in the fungal pathogen Histoplasma capsulatum. PLoS Biol 2019; 17:e3000168. [PMID: 31568523 PMCID: PMC6786654 DOI: 10.1371/journal.pbio.3000168] [Citation(s) in RCA: 15] [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: 02/01/2019] [Revised: 10/10/2019] [Accepted: 09/04/2019] [Indexed: 12/24/2022] Open
Abstract
Phenotypic switching between 2 opposing cellular states is a fundamental aspect of biology, and fungi provide facile systems to analyze the interactions between regulons that control this type of switch. A long-standing mystery in fungal pathogens of humans is how thermally dimorphic fungi switch their developmental form in response to temperature. These fungi, including the subject of this study, Histoplasma capsulatum, are temperature-responsive organisms that utilize unknown regulatory pathways to couple their cell shape and associated attributes to the temperature of their environment. H. capsulatum grows as a multicellular hypha in the soil that switches to a pathogenic yeast form in response to the temperature of a mammalian host. These states can be triggered in the laboratory simply by growing the fungus either at room temperature (RT; which promotes hyphal growth) or at 37 °C (which promotes yeast-phase growth). Prior worked revealed that 15% to 20% of transcripts are differentially expressed in response to temperature, but it is unclear which transcripts are linked to specific phenotypic changes, such as cell morphology or virulence. To elucidate temperature-responsive regulons, we previously identified 4 transcription factors (required for yeast-phase growth [Ryp]1-4) that are required for yeast-phase growth at 37 °C; in each ryp mutant, the fungus grows constitutively as hyphae regardless of temperature, and the cells fail to express genes that are normally induced in response to growth at 37 °C. Here, we perform the first genetic screen to identify genes required for hyphal growth of H. capsulatum at RT and find that disruption of the signaling mucin MSB2 results in a yeast-locked phenotype. RNA sequencing (RNAseq) experiments reveal that MSB2 is not required for the majority of gene expression changes that occur when cells are shifted to RT. However, a small subset of temperature-responsive genes is dependent on MSB2 for its expression, thereby implicating these genes in the process of filamentation. Disruption or knockdown of an Msb2-dependent mitogen-activated protein (MAP) kinase (HOG2) and an APSES transcription factor (STU1) prevents hyphal growth at RT, validating that the Msb2 regulon contains genes that control filamentation. Notably, the Msb2 regulon shows conserved hyphal-specific expression in other dimorphic fungi, suggesting that this work defines a small set of genes that are likely to be conserved regulators and effectors of filamentation in multiple fungi. In contrast, a few yeast-specific transcripts, including virulence factors that are normally expressed only at 37 °C, are inappropriately expressed at RT in the msb2 mutant, suggesting that expression of these genes is coupled to growth in the yeast form rather than to temperature. Finally, we find that the yeast-promoting transcription factor Ryp3 associates with the MSB2 promoter and inhibits MSB2 transcript expression at 37 °C, whereas Msb2 inhibits accumulation of Ryp transcripts and proteins at RT. These findings indicate that the Ryp and Msb2 circuits antagonize each other in a temperature-dependent manner, thereby allowing temperature to govern cell shape and gene expression in this ubiquitous fungal pathogen of humans.
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Affiliation(s)
- Lauren Rodriguez
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Mark Voorhies
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Sarah Gilmore
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Sinem Beyhan
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Anthony Myint
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
| | - Anita Sil
- Department of Microbiology and Immunology, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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21
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Westman J, Hube B, Fairn GD. Integrity under stress: Host membrane remodelling and damage by fungal pathogens. Cell Microbiol 2019; 21:e13016. [DOI: 10.1111/cmi.13016] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/30/2019] [Accepted: 02/05/2019] [Indexed: 12/28/2022]
Affiliation(s)
- Johannes Westman
- Program in Cell Biology The Hospital for Sick Children Toronto Ontario Canada
| | - Bernhard Hube
- Department Microbial Pathogenicity Mechanisms Hans Knoell Institute Jena Germany
- Institute of Microbiology Microbial Pathogenicity Friedrich Schiller University Jena Germany
| | - Gregory D. Fairn
- Keenan Research Centre for Biomedical Sciences St. Michael's Hospital Toronto Ontario Canada
- Department of Surgery University of Toronto Toronto Ontario Canada
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22
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Cissé OH, Hauser PM. Genomics and evolution of Pneumocystis species. INFECTION GENETICS AND EVOLUTION 2018; 65:308-320. [PMID: 30138710 DOI: 10.1016/j.meegid.2018.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 08/15/2018] [Accepted: 08/17/2018] [Indexed: 01/20/2023]
Abstract
The genus Pneumocystis comprises highly diversified fungal species that cause severe pneumonia in individuals with a deficient immune system. These fungi infect exclusively mammals and present a strict host species specificity. These species have co-diverged with their hosts for long periods of time (> 100 MYA). Details of their biology and evolution are fragmentary mainly because of a lack of an established long-term culture system. Recent genomic advances have unlocked new areas of research and allow new hypotheses to be tested. We review here new findings of the genomic studies in relation with the evolutionary trajectory of these fungi and discuss the impact of genomic data analysis in the context of the population genetics. The combination of slow genome decay and limited expansion of specific gene families and introns reflect intimate interactions of these species with their hosts. The evolutionary adaptation of these organisms is profoundly influenced by their population structure, which in turn is determined by intrinsic features such as their self-fertilizing mating system, high host specificity, long generation times, and transmission mode. Essential key questions concerning their adaptation and speciation remain to be answered. The next cornerstone will consist in the establishment of a long-term culture system and genetic manipulation that should allow unravelling the driving forces of Pneumocystis species evolution.
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Affiliation(s)
- Ousmane H Cissé
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Philippe M Hauser
- Institute of Microbiology, Lausanne University Hospital, Lausanne, Switzerland.
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23
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McBride JA, Gauthier GM, Klein BS. Turning on virulence: Mechanisms that underpin the morphologic transition and pathogenicity of Blastomyces. Virulence 2018. [PMID: 29532714 PMCID: PMC6779398 DOI: 10.1080/21505594.2018.1449506] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
This review article focuses on the mechanisms underlying temperature adaptation and virulence of the etiologic agents of blastomycosis, Blastomyces dermatitidis, Blastomyces gilchristii, and Blastomyces percursus. In response to temperature, Blastomyces undergoes a reversible morphologic switch between hyphae and yeast known as the phase transition. The conversion to yeast for Blastomyces and related thermally dimorphic fungi is essential for virulence. In the yeast phase, Blastomyces upregulates the essential virulence factor, BAD1, which promotes attachment to host cells, impairs activation of immune cells, and blunts cytokine release. Blastomyces yeast also secrete dipeptidyl-peptidase IVA (DPPIVA), a serine protease that blunts the action of cytokines released from host immune cells. In vivo transcriptional profiling of Blastomyces yeast has uncovered genes such as PRA1 and ZRT1 involved in zinc scavenging that contribute to virulence during murine pulmonary infection. The discovery and characterization of genes important for virulence has led to advances at the bedside regarding novel diagnostics, vaccine development, and new targets for drug discovery.
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Affiliation(s)
- Joseph A McBride
- Division of Infectious Disease, Department of Medicine, University of Wisconsin School of Medicine and Public Health , 600 Highland Avenue, Madison , WI , USA.,Division of Infectious Disease, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health , 1675 Highland Avenue, Madison , WI , USA
| | - Gregory M Gauthier
- Division of Infectious Disease, Department of Medicine, University of Wisconsin School of Medicine and Public Health , 600 Highland Avenue, Madison , WI , USA
| | - Bruce S Klein
- Division of Infectious Disease, Department of Medicine, University of Wisconsin School of Medicine and Public Health , 600 Highland Avenue, Madison , WI , USA.,Division of Infectious Disease, Department of Pediatrics, University of Wisconsin School of Medicine and Public Health , 1675 Highland Avenue, Madison , WI , USA.,Department of Medical Microbiology and Immunology, University of Wisconsin School of Medicine and Public Health , 1550 Linden Drive, Madison , WI , USA
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24
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Hernandez H, Martinez LR. Relationship of environmental disturbances and the infectious potential of fungi. MICROBIOLOGY-SGM 2018; 164:233-241. [PMID: 29458659 DOI: 10.1099/mic.0.000620] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Fungi are critical organisms for the environment and offer many benefits to modern society through their application in the pharmaceutical, beverage and food industries. In contrast, fungal pathogens are emerging threats to humans, animals, plants and insects with potential to cause devastating mortality, morbidity and economic loss. Outbreaks associated with anthropogenic alterations of the environment, including climate change-related events such as natural disasters, are responsible for human, animal and plant disease. Similarly, fungi and their metabolites also have a negative impact in agriculture, posing a serious threat to our food supplies. Here, we describe the existing knowledge and importance of understanding the relationship of fungi and the environment in the context of human, animal and plant disease. Our goal is to encourage communication between scientists and the general public to create informed awareness about the impact of fungi in their daily lives and their environment.
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Affiliation(s)
- Hazael Hernandez
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, TX, USA
| | - Luis R Martinez
- Department of Biological Sciences, The Border Biomedical Research Center, The University of Texas at El Paso, TX, USA
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25
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Abstract
Fungi must meet four criteria to infect humans: growth at human body temperatures, circumvention or penetration of surface barriers, lysis and absorption of tissue, and resistance to immune defenses, including elevated body temperatures. Morphogenesis between small round, detachable cells and long, connected cells is the mechanism by which fungi solve problems of locomotion around or through host barriers. Secretion of lytic enzymes, and uptake systems for the released nutrients, are necessary if a fungus is to nutritionally utilize human tissue. Last, the potent human immune system evolved in the interaction with potential fungal pathogens, so few fungi meet all four conditions for a healthy human host. Paradoxically, the advances of modern medicine have made millions of people newly susceptible to fungal infections by disrupting immune defenses. This article explores how different members of four fungal phyla use different strategies to fulfill the four criteria to infect humans: the Entomophthorales, the Mucorales, the Ascomycota, and the Basidiomycota. Unique traits confer human pathogenic potential on various important members of these phyla: pathogenic Onygenales comprising thermal dimorphs such as Histoplasma and Coccidioides; the Cryptococcus spp. that infect immunocompromised as well as healthy humans; and important pathogens of immunocompromised patients-Candida, Pneumocystis, and Aspergillus spp. Also discussed are agents of neglected tropical diseases important in global health such as mycetoma and paracoccidiomycosis and common pathogens rarely implicated in serious illness such as dermatophytes. Commensalism is considered, as well as parasitism, in shaping genomes and physiological systems of hosts and fungi during evolution.
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26
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Insights into the molecular basis for substrate binding and specificity of the fungal cystine transporter CgCYN1. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:2259-2268. [DOI: 10.1016/j.bbamem.2017.08.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Revised: 08/15/2017] [Accepted: 08/27/2017] [Indexed: 11/21/2022]
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27
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Shen Q, Rappleye CA. Differentiation of the fungus Histoplasma capsulatum into a pathogen of phagocytes. Curr Opin Microbiol 2017; 40:1-7. [PMID: 29096192 DOI: 10.1016/j.mib.2017.10.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 10/09/2017] [Indexed: 01/06/2023]
Abstract
Mammalian body temperature triggers differentiation of the fungal pathogen Histoplasma capsulatum into yeast cells. The Drk1 regulatory kinase and an interdependent network of Ryp transcription factors establish the yeast state. Beyond morphology, the differentiation-dependent expression program equips yeasts for invasion and survival within phagosomes. Yeast cells produce α-glucan and the Eng1 endoglucanase which hide yeasts from immune detection. Secretion of yeast phase-specific Sod3 and CatB detoxify phagocyte-derived reactive oxygen molecules. Histoplasma cells adapt to iron and zinc limitation in activated macrophages by production of siderophores and the Zrt2 transporter, respectively. Yeasts also respond to inflammation-associated hypoxia. Histoplasma pathogenicity thus relies on factors controlled by yeast differentiation as well as environment-dependent responses.
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Affiliation(s)
- Qian Shen
- Ohio State University, Columbus, OH 43210, USA
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28
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Uribe-Querol E, Rosales C. Control of Phagocytosis by Microbial Pathogens. Front Immunol 2017; 8:1368. [PMID: 29114249 PMCID: PMC5660709 DOI: 10.3389/fimmu.2017.01368] [Citation(s) in RCA: 141] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Accepted: 10/05/2017] [Indexed: 12/17/2022] Open
Abstract
Phagocytosis is a fundamental process of cells to capture and ingest foreign particles. Small unicellular organisms such as free-living amoeba use this process to acquire food. In pluricellular organisms, phagocytosis is a universal phenomenon that all cells are able to perform (including epithelial, endothelial, fibroblasts, etc.), but some specialized cells (such as neutrophils and macrophages) perform this very efficiently and were therefore named professional phagocytes by Rabinovitch. Cells use phagocytosis to capture and clear all particles larger than 0.5 µm, including pathogenic microorganisms and cellular debris. Phagocytosis involves a series of steps from recognition of the target particle, ingestion of it in a phagosome (phagocytic vacuole), maturation of this phagosome into a phagolysosome, to the final destruction of the ingested particle in the robust antimicrobial environment of the phagolysosome. For the most part, phagocytosis is an efficient process that eliminates invading pathogens and helps maintaining homeostasis. However, several pathogens have also evolved different strategies to prevent phagocytosis from proceeding in a normal way. These pathogens have a clear advantage to perpetuate the infection and continue their replication. Here, we present an overview of the phagocytic process with emphasis on the antimicrobial elements professional phagocytes use. We also summarize the current knowledge on the microbial strategies different pathogens use to prevent phagocytosis either at the level of ingestion, phagosome formation, and maturation, and even complete escape from phagosomes.
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Affiliation(s)
- Eileen Uribe-Querol
- División de Estudios de Posgrado e Investigación, Facultad de Odontología, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Carlos Rosales
- Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
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29
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Hernández-Chávez MJ, Pérez-García LA, Niño-Vega GA, Mora-Montes HM. Fungal Strategies to Evade the Host Immune Recognition. J Fungi (Basel) 2017; 3:jof3040051. [PMID: 29371567 PMCID: PMC5753153 DOI: 10.3390/jof3040051] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 12/23/2022] Open
Abstract
The recognition of fungal cells by the host immune system is key during the establishment of a protective anti-fungal response. Even though the immune system has evolved a vast number of processes to control these organisms, they have developed strategies to fight back, avoiding the proper recognition by immune components and thus interfering with the host protective mechanisms. Therefore, the strategies to evade the immune system are as important as the virulence factors and attributes that damage the host tissues and cells. Here, we performed a thorough revision of the main fungal tactics to escape from the host immunosurveillance processes. These include the composition and organization of the cell wall, the fungal capsule, the formation of titan cells, biofilms, and asteroid bodies; the ability to undergo dimorphism; and the escape from nutritional immunity, extracellular traps, phagocytosis, and the action of humoral immune effectors.
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Affiliation(s)
- Marco J Hernández-Chávez
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato Gto. 36050, México.
| | - Luis A Pérez-García
- Unidad Académica Multidisciplinaria Zona Huasteca, Universidad Autónoma de San Luis Potosí, Romualdo del Campo 501, Fracc. Rafael Curiel, C.P., Cd. Valle SLP. 79060, México.
| | - Gustavo A Niño-Vega
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato Gto. 36050, México.
| | - Héctor M Mora-Montes
- Departamento de Biología, División de Ciencias Naturales y Exactas, Campus Guanajuato, Universidad de Guanajuato, Noria Alta s/n, col. Noria Alta, C.P., Guanajuato Gto. 36050, México.
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Large-scale genomic analyses of in vitro yeast-mycelium dimorphism in human, insect and plant pathogenic fungi: From ESTs to RNAseq experiments. FUNGAL BIOL REV 2017. [DOI: 10.1016/j.fbr.2017.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Fungal Dimorphism and Virulence: Molecular Mechanisms for Temperature Adaptation, Immune Evasion, and In Vivo Survival. Mediators Inflamm 2017. [PMID: 28626345 PMCID: PMC5463121 DOI: 10.1155/2017/8491383] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The thermally dimorphic fungi are a unique group of fungi within the Ascomycota phylum that respond to shifts in temperature by converting between hyphae (22–25°C) and yeast (37°C). This morphologic switch, known as the phase transition, defines the biology and lifestyle of these fungi. The conversion to yeast within healthy and immunocompromised mammalian hosts is essential for virulence. In the yeast phase, the thermally dimorphic fungi upregulate genes involved with subverting host immune defenses. This review highlights the molecular mechanisms governing the phase transition and recent advances in how the phase transition promotes infection.
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Marcos CM, de Oliveira HC, de Melo WDCMA, da Silva JDF, Assato PA, Scorzoni L, Rossi SA, de Paula E Silva ACA, Mendes-Giannini MJS, Fusco-Almeida AM. Anti-Immune Strategies of Pathogenic Fungi. Front Cell Infect Microbiol 2016; 6:142. [PMID: 27896220 PMCID: PMC5108756 DOI: 10.3389/fcimb.2016.00142] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Accepted: 10/13/2016] [Indexed: 12/24/2022] Open
Abstract
Pathogenic fungi have developed many strategies to evade the host immune system. Multiple escape mechanisms appear to function together to inhibit attack by the various stages of both the adaptive and the innate immune response. Thus, after entering the host, such pathogens fight to overcome the immune system to allow their survival, colonization and spread to different sites of infection. Consequently, the establishment of a successful infectious process is closely related to the ability of the pathogen to modulate attack by the immune system. Most strategies employed to subvert or exploit the immune system are shared among different species of fungi. In this review, we summarize the main strategies employed for immune evasion by some of the major pathogenic fungi.
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Affiliation(s)
- Caroline M Marcos
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Haroldo C de Oliveira
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Wanessa de Cássia M Antunes de Melo
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Julhiany de Fátima da Silva
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Patrícia A Assato
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Liliana Scorzoni
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Suélen A Rossi
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Ana C A de Paula E Silva
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Maria J S Mendes-Giannini
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
| | - Ana M Fusco-Almeida
- Laboratório de Micologia Clínica, Departamento de Análises Clínicas, Faculdade de Ciências Farmacêuticas, Univ Estadual Paulista São Paulo, Brasil
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DuBois JC, Smulian AG. Sterol Regulatory Element Binding Protein (Srb1) Is Required for Hypoxic Adaptation and Virulence in the Dimorphic Fungus Histoplasma capsulatum. PLoS One 2016; 11:e0163849. [PMID: 27711233 PMCID: PMC5053422 DOI: 10.1371/journal.pone.0163849] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Accepted: 09/08/2016] [Indexed: 01/12/2023] Open
Abstract
The Histoplasma capsulatum sterol regulatory element binding protein (SREBP), Srb1 is a member of the basic helix-loop-helix (bHLH), leucine zipper DNA binding protein family of transcription factors that possess a unique tyrosine (Y) residue instead of an arginine (R) residue in the bHLH region. We have determined that Srb1 message levels increase in a time dependent manner during growth under oxygen deprivation (hypoxia). To further understand the role of Srb1 during infection and hypoxia, we silenced the gene encoding Srb1 using RNA interference (RNAi); characterized the resulting phenotype, determined its response to hypoxia, and its ability to cause disease within an infected host. Silencing of Srb1 resulted in a strain of H. capsulatum that is incapable of surviving in vitro hypoxia. We found that without complete Srb1 expression, H. capsulatum is killed by murine macrophages and avirulent in mice given a lethal dose of yeasts. Additionally, silencing Srb1 inhibited the hypoxic upregulation of other known H. capsulatum hypoxia-responsive genes (HRG), and genes that encode ergosterol biosynthetic enzymes. Consistent with these regulatory functions, Srb1 silenced H. capsulatum cells were hypersensitive to the antifungal azole drug itraconazole. These data support the theory that the H. capsulatum SREBP is critical for hypoxic adaptation and is required for H. capsulatum virulence.
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Affiliation(s)
- Juwen C. DuBois
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- Cincinnati VA Medical Center, Cincinnati, Ohio, United States of America
| | - A. George Smulian
- Cincinnati VA Medical Center, Cincinnati, Ohio, United States of America
- Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- * E-mail:
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Kirkland TN. A few shared up-regulated genes may influence conidia to yeast transformation in dimorphic fungal pathogens. Med Mycol 2016; 54:648-53. [PMID: 27118798 DOI: 10.1093/mmy/myw019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Accepted: 03/10/2016] [Indexed: 01/13/2023] Open
Abstract
The small number of fungi that commonly cause disease in normal people share the capacity to grow as mycelia in the soil at 25°C and as yeast (or spherules) in mammals at 37°C. This remarkable conversion has long been a topic of interest in medical mycology. The conidia to yeast conversion has been studied by transcription profiling in several fungal species, including Histoplasma capsulatum, Paracoccidioides brasiliensis, Coccidioides spp., Blastomyces dermatitidis, and Talaromyces marneffei One limitation of transcriptional profiling is determining which genes are involved in the process of conversion to yeast as opposed to a result of conversion to yeast. If there are genes that are up-regulated in the yeast phase of more than one dimorphic, pathogenic fungus they might be required for conversion to yeast (or spherules). To address this issue, 24 up-regulated genes common to Coccidioides spp spherules and H. capsulatum yeasts were identified. Four homologs of these genes were also found in P. brasiliensis, B. dermatitidis or T. marneffei genes that were up-regulated in yeast. 4-hydroxyphenylpurvate dioxygenase, a gene involved in tyrosine metabolism and melanin synthesis that has been shown to be required for yeast conversion, is conserved and up-regulated in yeast in all five species. Another up-regulated gene that is conserved in all five species is a MFS sugar porter. These results suggest that a minority of up-regulated yeast (or spherule) genes are conserved across species and raises the possibility that conserved up-regulated genes may be of special interest for differentiation of mycelium into yeast.
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35
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Revisiting old friends: Developments in understanding Histoplasma capsulatum pathogenesis. J Microbiol 2016; 54:265-76. [DOI: 10.1007/s12275-016-6044-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 02/02/2016] [Indexed: 12/27/2022]
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36
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RNAseq Analysis Highlights Specific Transcriptome Signatures of Yeast and Mycelial Growth Phases in the Dutch Elm Disease Fungus Ophiostoma novo-ulmi. G3-GENES GENOMES GENETICS 2015; 5:2487-95. [PMID: 26384770 PMCID: PMC4632067 DOI: 10.1534/g3.115.021022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Fungal dimorphism is a complex trait and our understanding of the ability of fungi to display different growth morphologies is limited to a small number of model species. Here we study a highly aggressive dimorphic fungus, the ascomycete Ophiostoma novo-ulmi, which is a model in plant pathology and the causal agent of Dutch elm disease. The two growth phases that this fungus displays, i.e., a yeast phase and mycelial phase, are thought to be involved in key steps of disease development. We used RNAseq to investigate the genome-wide gene expression profiles that are associated with yeast and mycelial growth phases in vitro. Our results show a clear molecular distinction between yeast and mycelial phase gene expression profiles. Almost 12% of the gene content is differentially expressed between the two phases, which reveals specific functions related to each growth phase. We compared O. novo-ulmi transcriptome profiles with those of two model dimorphic fungi, Candida albicans and Histoplasma capsulatum. Few orthologs showed similar expression regulation between the two growth phases, which suggests that, globally, the genes associated with these two life forms are poorly conserved. This poor conservation underscores the importance of developing specific tools for emerging model species that are distantly related to the classical ones. Taken together, our results provide insights into transcriptome regulation and molecular specificity in O. novo-ulmi and offer a new perspective for understanding fungal dimorphism.
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Gilmore SA, Voorhies M, Gebhart D, Sil A. Genome-Wide Reprogramming of Transcript Architecture by Temperature Specifies the Developmental States of the Human Pathogen Histoplasma. PLoS Genet 2015; 11:e1005395. [PMID: 26177267 PMCID: PMC4503680 DOI: 10.1371/journal.pgen.1005395] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 06/26/2015] [Indexed: 11/28/2022] Open
Abstract
Eukaryotic cells integrate layers of gene regulation to coordinate complex cellular processes; however, mechanisms of post-transcriptional gene regulation remain poorly studied. The human fungal pathogen Histoplasma capsulatum (Hc) responds to environmental or host temperature by initiating unique transcriptional programs to specify multicellular (hyphae) or unicellular (yeast) developmental states that function in infectivity or pathogenesis, respectively. Here we used recent advances in next-generation sequencing to uncover a novel re-programming of transcript length between Hc developmental cell types. We found that ~2% percent of Hc transcripts exhibit 5’ leader sequences that differ markedly in length between morphogenetic states. Ribosome density and mRNA abundance measurements of differential leader transcripts revealed nuanced transcriptional and translational regulation. One such class of regulated longer leader transcripts exhibited tight transcriptional and translational repression. Further examination of these dually repressed genes revealed that some control Hc morphology and that their strict regulation is necessary for the pathogen to make appropriate developmental decisions in response to temperature. Eukaryotic cells alter their developmental programs in response to environmental signals. Histoplasma capsulatum (Hc), a ubiquitous fungal pathogen of humans, establishes unique transcriptional programs to specify growth in either a multicellular hyphal form or unicellular yeast form in response to temperature. Since hyphae and yeast are specialized to function in infectivity or pathogenesis, respectively, Hc provides a clinically relevant system in which to query eukaryotic regulatory processes. Here we used next-generation sequencing approaches to annotate the transcriptomes of four distinct Hc strains in response to temperature. We found that a fraction of Hc transcripts have differential transcript architecture in hyphae and yeast, exhibiting 5’ leader sequences that differ markedly in length between morphogenetic states. To begin to understand the effect of these differential leader sequences on expression, we performed the first ribosome density and mRNA abundance measurements in Hc, thereby uncovering transcriptional and translational control that contribute to cell-type regulation.
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Affiliation(s)
- Sarah A. Gilmore
- Department of Microbiology and Immunology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Mark Voorhies
- Department of Microbiology and Immunology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Dana Gebhart
- Department of Microbiology and Immunology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
| | - Anita Sil
- Department of Microbiology and Immunology, Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, California, United States of America
- * E-mail:
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38
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Affiliation(s)
- Gregory M. Gauthier
- Department of Medicine, University of Wisconsin, Madison, Wisconsin, United States of America
- * E-mail:
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39
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Muñoz JF, Gallo JE, Misas E, Priest M, Imamovic A, Young S, Zeng Q, Clay OK, McEwen JG, Cuomo CA. Genome update of the dimorphic human pathogenic fungi causing paracoccidioidomycosis. PLoS Negl Trop Dis 2014; 8:e3348. [PMID: 25474325 PMCID: PMC4256289 DOI: 10.1371/journal.pntd.0003348] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Accepted: 10/14/2014] [Indexed: 11/19/2022] Open
Abstract
Paracoccidiodomycosis (PCM) is a clinically important fungal disease that can acquire serious systemic forms and is caused by the thermodimorphic fungal Paracoccidioides spp. PCM is a tropical disease that is endemic in Latin America, where up to ten million people are infected; 80% of reported cases occur in Brazil, followed by Colombia and Venezuela. To enable genomic studies and to better characterize the pathogenesis of this dimorphic fungus, two reference strains of P. brasiliensis (Pb03, Pb18) and one strain of P. lutzii (Pb01) were sequenced [1]. While the initial draft assemblies were accurate in large scale structure and had high overall base quality, the sequences had frequent small scale defects such as poor quality stretches, unknown bases (N's), and artifactual deletions or nucleotide duplications, all of which caused larger scale errors in predicted gene structures. Since assembly consensus errors can now be addressed using next generation sequencing (NGS) in combination with recent methods allowing systematic assembly improvement, we re-sequenced the three reference strains of Paracoccidioides spp. using Illumina technology. We utilized the high sequencing depth to re-evaluate and improve the original assemblies generated from Sanger sequence reads, and obtained more complete and accurate reference assemblies. The new assemblies led to improved transcript predictions for the vast majority of genes of these reference strains, and often substantially corrected gene structures. These include several genes that are central to virulence or expressed during the pathogenic yeast stage in Paracoccidioides and other fungi, such as HSP90, RYP1-3, BAD1, catalase B, alpha-1,3-glucan synthase and the beta glucan synthase target gene FKS1. The improvement and validation of these reference sequences will now allow more accurate genome-based analyses. To our knowledge, this is one of the first reports of a fully automated and quality-assessed upgrade of a genome assembly and annotation for a non-model fungus. The fungal genus Paracoccidioides is the causal agent of paracoccidioidomycosis (PCM), a neglected tropical disease that is endemic in several countries of South America. Paracoccidioides is a pathogenic dimorphic fungus that is capable of converting to a virulent yeast form after inhalation by the host. Therefore the molecular biology of the switch to the yeast phase is of particular interest for understanding the virulence of this and other human pathogenic fungi, and ultimately for reducing the morbidity and mortality caused by such fungal infections. We here present the strategy and methods we used to update and improve accuracy of three reference genome sequences of Paracoccidioides spp. utilizing state-of-the-art Illumina re-sequencing, assembly improvement, re-annotation, and quality assessment. The resulting improved genome resource should be of wide use not solely for advancing research on the genetics and molecular biology of Paracoccidioides and the closely related pathogenic species Histoplasma and Blastomyces, but also for fungal diagnostics based on sequencing or molecular assays, characterizing rapidly changing proteins that may be involved in virulence, SNP-based population analyses and other tasks that require high sequence accuracy. The genome update and underlying strategy and methods also serve as a proof of principle that could encourage similar improvements of other draft genomes.
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Affiliation(s)
- José F. Muñoz
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- Institute of Biology, Universidad de Antioquia, Medellín, Colombia
| | - Juan E. Gallo
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- Doctoral Program in Biomedical Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Elizabeth Misas
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- Institute of Biology, Universidad de Antioquia, Medellín, Colombia
| | - Margaret Priest
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Alma Imamovic
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Sarah Young
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Qiandong Zeng
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
| | - Oliver K. Clay
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá, Colombia
| | - Juan G. McEwen
- Cellular and Molecular Biology Unit, Corporación para Investigaciones Biológicas, Medellín, Colombia
- School of Medicine, Universidad de Antioquia, Medellín, Colombia
| | - Christina A. Cuomo
- Broad Institute of MIT and Harvard, Cambridge, Massachusetts, United States of America
- * E-mail:
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40
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Gilbert AS, Wheeler RT, May RC. Fungal Pathogens: Survival and Replication within Macrophages. Cold Spring Harb Perspect Med 2014; 5:a019661. [PMID: 25384769 DOI: 10.1101/cshperspect.a019661] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The innate immune system is a critical line of defense against pathogenic fungi. Macrophages act at an early stage of infection, detecting and phagocytizing infectious propagules. To avoid killing at this stage, fungal pathogens use diverse strategies ranging from evasion of uptake to intracellular parasitism. This article will discuss five of the most important human fungal pathogens (Candida albicans, Aspergillus fumigatus, Cryptococcus neoformans, Coccidiodes immitis, and Histoplasma capsulatum) and consider the strategies and virulence factors adopted by each to survive and replicate within macrophages.
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Affiliation(s)
- Andrew S Gilbert
- Institute of Microbiology and Infection & School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom
| | - Robert T Wheeler
- Department of Molecular and Biomedical Sciences, University of Maine, Orono, Maine 04469 Graduate School of Biomedical Sciences and Engineering, University Hospitals of Birmingham NHS Foundation Trust, Queen Elizabeth Hospital, Birmingham B15 2TG, United Kingdom
| | - Robin C May
- Institute of Microbiology and Infection & School of Biosciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom NIHR Surgical Reconstruction and Microbiology Research Centre, University Hospitals of Birmingham NHS Foundation Trust, Queen Elizabeth Hospital, Birmingham B15 2TG, United Kingdom
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Meijueiro ML, Santoyo F, Ramirez L, Pisabarro AG. Transcriptome characteristics of filamentous fungi deduced using high-throughput analytical technologies. Brief Funct Genomics 2014; 13:440-50. [DOI: 10.1093/bfgp/elu033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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Abstract
Fungal pathogens must assimilate local nutrients to establish an infection in their mammalian host. We focus on carbon, nitrogen, and micronutrient assimilation mechanisms, discussing how these influence host-fungus interactions during infection. We highlight several emerging trends based on the available data. First, the perturbation of carbon, nitrogen, or micronutrient assimilation attenuates fungal pathogenicity. Second, the contrasting evolutionary pressures exerted on facultative versus obligatory pathogens have led to contemporary pathogenic fungal species that display differing degrees of metabolic flexibility. The evolutionarily ancient metabolic pathways are conserved in most fungal pathogen, but interesting gaps exist in some species (e.g., Candida glabrata). Third, metabolic flexibility is generally essential for fungal pathogenicity, and in particular, for the adaptation to contrasting host microenvironments such as the gastrointestinal tract, mucosal surfaces, bloodstream, and internal organs. Fourth, this metabolic flexibility relies on complex regulatory networks, some of which are conserved across lineages, whereas others have undergone significant evolutionary rewiring. Fifth, metabolic adaptation affects fungal susceptibility to antifungal drugs and also presents exciting opportunities for the development of novel therapies.
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Affiliation(s)
- Iuliana V Ene
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Sascha Brunke
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany
| | - Alistair J P Brown
- Aberdeen Fungal Group, School of Medical Sciences, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen AB25 2ZD, United Kingdom
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Hans Knoell Institute, 07745 Jena, Germany Friedrich Schiller University, 07743 Jena, Germany Center for Sepsis Control and Care, Universitätsklinikum Jena, 07747 Jena, Germany
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Abstract
Endemic mycoses remain a significant cause of morbidity and mortality among immunocompromised patients. As the number of immunosuppressed individuals increases worldwide, the incidence of endemic mycoses is also expected to rise. In immunocompromised patients, endemic mycoses can present in atypical fashion, cause more severe and/or disseminated disease, and result in higher mortality. Despite several noteworthy advances over the past decade, significant challenges remain with regard to the prevention, diagnosis, and therapy of endemic mycoses in immunocompromised hosts. This review highlights important developments related to the epidemiology, diagnosis, treatment, and prevention of commonly encountered endemic mycoses. We also discuss emerging topics, knowledge gaps, and areas of future research.
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Edwards JA, Chen C, Kemski MM, Hu J, Mitchell TK, Rappleye CA. Histoplasma yeast and mycelial transcriptomes reveal pathogenic-phase and lineage-specific gene expression profiles. BMC Genomics 2013; 14:695. [PMID: 24112604 PMCID: PMC3852720 DOI: 10.1186/1471-2164-14-695] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 10/07/2013] [Indexed: 11/13/2022] Open
Abstract
Background The dimorphic fungus Histoplasma capsulatum causes respiratory and systemic disease in mammalian hosts by expression of factors that enable survival within phagocytic cells of the immune system. Histoplasma’s dimorphism is distinguished by growth either as avirulent mycelia or as pathogenic yeast. Geographically distinct strains of Histoplasma differ in their relative virulence in mammalian hosts and in production of and requirement for specific virulence factors. The close similarity in the genome sequences of these diverse strains suggests that phenotypic variations result from differences in gene expression rather than gene content. To provide insight into how the transcriptional program translates into morphological variation and the pathogenic lifestyle, we compared the transcriptional profile of the pathogenic yeast phase and the non-pathogenic mycelial phase of two clinical isolates of Histoplasma. Results To overcome inaccuracies in ab initio genome annotation of the Histoplasma genome, we used RNA-seq methodology to generate gene structure models based on experimental evidence. Quantitative analyses of the sequencing reads revealed 6% to 9% of genes are differentially regulated between the two phases. RNA-seq-based mRNA quantitation was strongly correlated with gene expression levels determined by quantitative RT-PCR. Comparison of the yeast-phase transcriptomes between strains showed 7.6% of all genes have lineage-specific expression differences including genes contributing, or potentially related, to pathogenesis. GFP-transcriptional fusions and their introduction into both strain backgrounds revealed that the difference in transcriptional activity of individual genes reflects both variations in the cis- and trans-acting factors between Histoplasma strains. Conclusions Comparison of the yeast and mycelial transcriptomes highlights genes encoding virulence factors as well as those involved in protein glycosylation, alternative metabolism, lipid remodeling, and cell wall glycanases that may contribute to Histoplasma pathogenesis. These studies lay an essential foundation for understanding how gene expression variations contribute to the strain- and phase-specific virulence differences of Histoplasma.
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Affiliation(s)
- Jessica A Edwards
- The Department of Microbiology, Ohio State University, 484 W, 12th Ave,, Columbus, OH 43210, USA.
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