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Santos TADO, Soares LW, Oliveira LN, Moraes D, Mendes MS, Soares CMDA, Bailão AM, Bailão MGS. Zinc Starvation Induces Cell Wall Remodeling and Activates the Antioxidant Defense System in Fonsecaea pedrosoi. J Fungi (Basel) 2024; 10:118. [PMID: 38392790 PMCID: PMC10890210 DOI: 10.3390/jof10020118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/24/2024] Open
Abstract
The survival of pathogenic fungi in the host after invasion depends on their ability to obtain nutrients, which include the transition metal zinc. This essential micronutrient is required to maintain the structure and function of various proteins and, therefore, plays a critical role in various biological processes. The host's nutritional immunity limits the availability of zinc to pathogenic fungi mainly by the action of calprotectin, a component of neutrophil extracellular traps. Here we investigated the adaptive responses of Fonsecaea pedrosoi to zinc-limiting conditions. This black fungus is the main etiological agent of chromoblastomycosis, a chronic neglected tropical disease that affects subcutaneous tissues. Following exposure to a zinc-limited environment, F. pedrosoi induces a high-affinity zinc uptake machinery, composed of zinc transporters and the zincophore Pra1. A proteomic approach was used to define proteins regulated by zinc deprivation. Cell wall remodeling, changes in neutral lipids homeostasis, and activation of the antioxidant system were the main strategies for survival in the hostile environment. Furthermore, the downregulation of enzymes required for sulfate assimilation was evident. Together, the adaptive responses allow fungal growth and development and reveals molecules that may be related to fungal persistence in the host.
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Affiliation(s)
| | - Lucas Weba Soares
- Laboratory of Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
- Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Lucas Nojosa Oliveira
- Laboratory of Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
| | - Dayane Moraes
- Laboratory of Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
| | - Millena Silva Mendes
- Laboratory of Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
| | - Célia Maria de Almeida Soares
- Laboratory of Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
| | - Alexandre Melo Bailão
- Laboratory of Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
| | - Mirelle Garcia Silva Bailão
- Laboratory of Molecular Biology, Institute of Biological Sciences, Federal University of Goiás, Goiânia 74690-900, GO, Brazil
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2
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Azevedo MJ, Araujo R, Campos J, Campos C, Ferreira AF, Falcão-Pires I, Ramalho C, Zaura E, Pinto E, Sampaio-Maia B. Vertical Transmission and Antifungal Susceptibility Profile of Yeast Isolates from the Oral Cavity, Gut, and Breastmilk of Mother-Child Pairs in Early Life. Int J Mol Sci 2023; 24:ijms24021449. [PMID: 36674962 PMCID: PMC9867488 DOI: 10.3390/ijms24021449] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/06/2023] [Accepted: 01/07/2023] [Indexed: 01/13/2023] Open
Abstract
Yeast acquisition begins at birth; however, the contribution of the mother on yeast transmission to the offspring and associated resistance is yet to be clarified. The aim of this study was to explore the vertical transmission of yeasts and their antifungal susceptibility profile in early life. Oral, fecal, and breastmilk samples were collected from 73 mother-child pairs four to twelve weeks after delivery and cultured on Sabouraud dextrose agar with chloramphenicol. The isolates were identified by MALDI-TOF MS. The vertical transmission was studied by microsatellite genotyping. Antifungal susceptibility was determined for fluconazole, voriconazole, miconazole, anidulafungin, and nystatin by broth microdilution assay, following CLSI-M60 guidelines. A total of 129 isolates were identified from 53% mother-child pairs. We verified the vertical transmission of Candida albicans (n = three mother-child pairs) and Candida parapsilosis (n = one mother-child pair) strains, including an antifungal resistant strain transmitted from breastmilk to the gut of a child. Most isolates were susceptible to the tested antifungals, with the exception of four C. albicans isolates and one R. mucilaginosa isolate. The vertical transmission of yeasts happens in early life. This is the first work that demonstrated the role of the mother as a source of transmission of antifungal-resistant yeasts to the child.
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Affiliation(s)
- Maria João Azevedo
- INEB—Instituto Nacional de Engenharia Biomédica, 4150-177 Porto, Portugal
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- Department of Preventive Dentistry, Academic Center for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, 1081 LA Amsterdam, The Netherlands
| | - Ricardo Araujo
- INEB—Instituto Nacional de Engenharia Biomédica, 4150-177 Porto, Portugal
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Joana Campos
- INEB—Instituto Nacional de Engenharia Biomédica, 4150-177 Porto, Portugal
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Carla Campos
- Serviço de Patologia Clínica, Departamento de Patologia e Medicina Laboratorial, Instituto Português de Oncologia do Porto Francisco Gentil, 4200-072 Porto, Portugal
- Escola Superior de Saúde, Instituto Politécnico do Porto, 4200-072 Porto, Portugal
| | | | - Inês Falcão-Pires
- Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal
| | - Carla Ramalho
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- Faculdade de Medicina, Universidade do Porto, 4200-319 Porto, Portugal
- Department of Gynecology and Obstetrics, Centro Hospitalar Universitário de São João, 4200-319 Porto, Portugal
| | - Egija Zaura
- Department of Preventive Dentistry, Academic Center for Dentistry Amsterdam, University of Amsterdam and Vrije Universiteit Amsterdam, 1081 LA Amsterdam, The Netherlands
| | - Eugénia Pinto
- Faculdade de Farmácia, Universidade do Porto, 4050-313 Porto, Portugal
- Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, 4450-208 Matosinhos, Portugal
| | - Benedita Sampaio-Maia
- INEB—Instituto Nacional de Engenharia Biomédica, 4150-177 Porto, Portugal
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
- Faculdade de Medicina Dentária, Universidade do Porto, 4200-393 Porto, Portugal
- Correspondence:
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3
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Fungal Zinc Homeostasis and Its Potential as an Antifungal Target: A Focus on the Human Pathogen Aspergillus fumigatus. Microorganisms 2022; 10:microorganisms10122469. [PMID: 36557722 PMCID: PMC9785309 DOI: 10.3390/microorganisms10122469] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/09/2022] [Accepted: 12/10/2022] [Indexed: 12/15/2022] Open
Abstract
Aspergillus fumigatus is an opportunistic airborne fungus that causes severe invasive aspergillosis in immunocompromised patients. Zinc is an essential micronutrient for the growth of A. fumigatus and even for all microorganisms. An increasing number of studies have reported that fungal zinc acquisition ability plays a key role in fungal survival in hosts with an extremely zinc-limited microenvironment. The ability to fight scarcity and excess of zinc are tightly related to fungal virulence and may be used as new potential targets. Because the regulation of zinc homeostasis is important, a thorough understanding of the functional genes involved in the regulatory network for zinc homeostasis is required for fungal pathogens. The current mini-review summarized potential zinc homeostasis regulators in A. fumigatus and classified these regulators according to localization and function, which were identified or predicted based on A. fumigatus or deduced from homologs in model yeasts. Future perspectives for zinc homeostasis regulators as potential antifungal targets to treat invasive aspergillosis are also discussed.
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4
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Garstka K, Hecel A, Kozłowski H, Rowińska-Żyrek M. Specific Zn(II)-binding site in the C-terminus of Aspf2, a zincophore from Aspergillus fumigatus. Metallomics 2022; 14:6608364. [PMID: 35700143 PMCID: PMC9780748 DOI: 10.1093/mtomcs/mfac042] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 05/23/2022] [Indexed: 12/27/2022]
Abstract
Aspergillus fumigatus, one of the most widespread opportunistic human fungal pathogens, adapts to zinc limitation by secreting a 310 amino acid Aspf2 zincophore, able to specifically bind Zn(II) and deliver it to a transmembrane zinc transporter, ZrfC. In this work, we focus on the thermodynamics of Zn(II) complexes with unstructured regions of Aspf2; basing on a variety of spectrometric and potentiometric data, we show that the C-terminal part has the highest Zn(II)-binding affinity among the potential binding sites, and Ni(II) does not compete with Zn(II) binding to this region. The 14 amino acid Aspf2 C-terminus coordinates Zn(II) via two Cys thiolates and two His imidazoles and it could be considered as a promising A. fumigatus targeting molecule.
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Affiliation(s)
- Kinga Garstka
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Aleksandra Hecel
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Henryk Kozłowski
- Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland,Institute of Health Sciences, University of Opole, Katowicka 68 St, 45-060 Opole, Poland
| | - Magdalena Rowińska-Żyrek
- Correspondence: Magdalena Rowińska-Żyrek, Faculty of Chemistry, University of Wrocław, F. Joliot-Curie 14, 50-383 Wrocław, Poland. E-mail:
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5
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The putative role of zinc homeostasis in grain formation by Madurella mycetomatis during mycetoma infection. FUNGAL BIOL REV 2022. [DOI: 10.1016/j.fbr.2021.12.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Wilson D. The role of zinc in the pathogenicity of human fungal pathogens. ADVANCES IN APPLIED MICROBIOLOGY 2021; 117:35-61. [PMID: 34742366 DOI: 10.1016/bs.aambs.2021.09.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Fungal pathogens now account for an unprecedented burden on human health. Like all microorganisms, these fungi must successfully forage for essential micronutrients such as zinc in order to proliferate. However, pathogenic microbes face an additional hurdle in securing zinc from their environment: the action of host nutritional immunity which strictly manipulates microbial access to this essential, but also potentially toxic trace metal. This review introduces the relevant pathogenic species and goes on to cover the molecular mechanisms of zinc uptake by human fungal pathogens. Fungi scavenge zinc from their environment via two basic mechanisms: via a family of cellular zinc importers-the ZIP transporters; and via a unique secreted zinc binding protein-the zincophore. However the genetic requirement of these systems for fungal virulence is highly species-specific. As well as zinc scarcity, potential intoxification with this heavy metal can occur and, unlike bacteria, fungi deal with environmental insult this via intraorganellar compartmentalization. Zinc availability also modulates the morphogenic behavior of a subset of pathogenic yeast species. This chapter will cover these different aspects of zinc availability on the physiology of human fungal pathogens with emphasis on the major pathogenic species Candida albicans.
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Affiliation(s)
- Duncan Wilson
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom.
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7
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Alamir OF, Oladele RO, Ibe C. Nutritional immunity: targeting fungal zinc homeostasis. Heliyon 2021; 7:e07805. [PMID: 34466697 PMCID: PMC8384899 DOI: 10.1016/j.heliyon.2021.e07805] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 06/22/2021] [Accepted: 08/12/2021] [Indexed: 12/15/2022] Open
Abstract
Transition metals, such as Zn2+, are essential dietary constituents of all biological life, including mammalian hosts and the pathogens that infect them. Therefore, to thrive and cause infection, pathogens must successfully assimilate these elements from the host milieu. Consequently, mammalian immunity has evolved to actively restrict and/or pool metals to toxic concentrations in an effort to attenuate microbial pathogenicity - a process termed nutritional immunity. Despite host-induced Zn2+ nutritional immunity, pathogens such as Candida albicans, are still capable of causing disease and thus must be equipped with robust Zn2+ sensory, uptake and detoxification machinery. This review will discuss the strategies employed by mammalian hosts to limit Zn2+ during infection, and the subsequent fungal interventions that counteract Zn2+ nutritional immunity.
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Affiliation(s)
- Omran F Alamir
- Department of Natural Sciences, College of Health Sciences, The Public Authority for Applied Education and Training, Al Asimah, Kuwait
| | - Rita O Oladele
- Department of Medical Microbiology & Parasitology, College of Medicine, University of Lagos, Lagos State, Nigeria
| | - C Ibe
- Department of Microbiology, Abia State University, PMB 2000, Uturu, Abia State, Nigeria
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8
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Nitrogen, Iron and Zinc Acquisition: Key Nutrients to Aspergillus fumigatus Virulence. J Fungi (Basel) 2021; 7:jof7070518. [PMID: 34203370 PMCID: PMC8303583 DOI: 10.3390/jof7070518] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 06/24/2021] [Accepted: 06/24/2021] [Indexed: 12/31/2022] Open
Abstract
Aspergillus fumigatus is a ubiquitous soil decomposer and an opportunistic pathogen that is characterized by its large metabolic machinery for acquiring nutrients from media. Lately, an ever-increasing number of genes involved in fungal nutrition has been associated with its virulence. Of these, nitrogen, iron, and zinc metabolism-related genes are particularly noteworthy, since 78% of them have a direct implication in virulence. In this review, we describe the sensing, uptake and regulation process of the acquisition of these nutrients, the connections between pathways and the virulence-implicated genes. Nevertheless, only 40% of the genes mentioned in this review have been assayed for roles in virulence, leaving a wide field of knowledge that remains uncertain and might offer new therapeutic and diagnostic targets.
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9
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Robinson JR, Isikhuemhen OS, Anike FN. Fungal-Metal Interactions: A Review of Toxicity and Homeostasis. J Fungi (Basel) 2021; 7:225. [PMID: 33803838 PMCID: PMC8003315 DOI: 10.3390/jof7030225] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 03/15/2021] [Accepted: 03/17/2021] [Indexed: 12/18/2022] Open
Abstract
Metal nanoparticles used as antifungals have increased the occurrence of fungal-metal interactions. However, there is a lack of knowledge about how these interactions cause genomic and physiological changes, which can produce fungal superbugs. Despite interest in these interactions, there is limited understanding of resistance mechanisms in most fungi studied until now. We highlight the current knowledge of fungal homeostasis of zinc, copper, iron, manganese, and silver to comprehensively examine associated mechanisms of resistance. Such mechanisms have been widely studied in Saccharomyces cerevisiae, but limited reports exist in filamentous fungi, though they are frequently the subject of nanoparticle biosynthesis and targets of antifungal metals. In most cases, microarray analyses uncovered resistance mechanisms as a response to metal exposure. In yeast, metal resistance is mainly due to the down-regulation of metal ion importers, utilization of metallothionein and metallothionein-like structures, and ion sequestration to the vacuole. In contrast, metal resistance in filamentous fungi heavily relies upon cellular ion export. However, there are instances of resistance that utilized vacuole sequestration, ion metallothionein, and chelator binding, deleting a metal ion importer, and ion storage in hyphal cell walls. In general, resistance to zinc, copper, iron, and manganese is extensively reported in yeast and partially known in filamentous fungi; and silver resistance lacks comprehensive understanding in both.
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Affiliation(s)
| | - Omoanghe S. Isikhuemhen
- Department of Natural Resources and Environmental Design, North Carolina Agricultural and Technical State University, 1601 East Market Street, Greensboro, NC 27411, USA; (J.R.R.); (F.N.A.)
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10
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Toledo H, Sánchez CI, Marín L, Amich J, Calera JA. Regulation of zinc homeostatic genes by environmental pH in the filamentous fungus Aspergillus fumigatus. Environ Microbiol 2021; 24:643-666. [PMID: 33687784 DOI: 10.1111/1462-2920.15452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 03/02/2021] [Accepted: 03/03/2021] [Indexed: 11/30/2022]
Abstract
Aspergillus fumigatus can grow over a broad range of pH values even though zinc availability is greatly conditioned by ambient pH. It has been previously shown that regulation of zinc homeostatic genes in this fungus relies on the transcription factor ZafA. In addition, their expression is further modulated by the transcription factor PacC depending on ambient pH, which allows this fungus to grow in diverse types of niches, including soils and the lungs of immunosuppressed hosts. In this work the regulation by PacC of genes zrfB and zrfC that are expressed, respectively, under acidic and alkaline zinc-limiting conditions have been analysed in detail. Thus, data that extend the current model for PacC function, including the role of the full-length PacC72 protein and the PacC processed forms (PacC53 and PacC27 ) on gene expression has been provided, and a new mechanism for the repression of acid-expressed genes in alkaline media based on interference with the start of transcription has been described. Moreover, it was proposed that the transcription of both acid-expressed and alkaline-expressed genes under zinc-limiting conditions might also rely on a third factor (putatively Pontin/Reptin), which may be required to integrate the action of PacC and ZafA into gene specific transcriptional responses.
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Affiliation(s)
- Héctor Toledo
- Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Servicio de Microbiología Clínica y Parasitología, Hospital Universitario Virgen del Rocío, Sevilla, Spain
| | - Clara Inés Sánchez
- Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Escuela de Microbiología, Universidad Industrial de Santander, Bucaramanga, Colombia
| | - Laura Marín
- Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Salamanca, Spain
| | - Jorge Amich
- Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain.,Manchester Fungal Infection Group, School of Biological Sciences, Faculty of Biology, Medicine and Health, University of Manchester, Manchester, UK
| | - José Antonio Calera
- Instituto de Biología Funcional y Genómica (IBFG-CSIC), Universidad de Salamanca, Salamanca, Spain.,Departamento de Microbiología y Genética, Universidad de Salamanca, Salamanca, Spain
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11
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Assunção LDP, Moraes D, Soares LW, Silva-Bailão MG, de Siqueira JG, Baeza LC, Báo SN, Soares CMDA, Bailão AM. Insights Into Histoplasma capsulatum Behavior on Zinc Deprivation. Front Cell Infect Microbiol 2020; 10:573097. [PMID: 33330123 PMCID: PMC7734293 DOI: 10.3389/fcimb.2020.573097] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/21/2020] [Indexed: 11/13/2022] Open
Abstract
Histoplasma capsulatum is a thermodimorphic fungus that causes histoplasmosis, a mycosis of global incidence. The disease is prevalent in temperate and tropical regions such as North America, South America, Europe, and Asia. It is known that during infection macrophages restrict Zn availability to H. capsulatum as a microbicidal mechanism. In this way the present work aimed to study the response of H. capsulatum to zinc deprivation. In silico analyses showed that H. capsulatum has eight genes related to zinc homeostasis ranging from transcription factors to CDF and ZIP family transporters. The transcriptional levels of ZAP1, ZRT1, and ZRT2 were induced under zinc-limiting conditions. The decrease in Zn availability increases fungicidal macrophage activity. Proteomics analysis during zinc deprivation at 24 and 48 h showed 265 proteins differentially expressed at 24 h and 68 at 48 h. Proteins related to energy production pathways, oxidative stress, and cell wall remodeling were regulated. The data also suggested that low metal availability increases the chitin and glycan content in fungal cell wall that results in smoother cell surface. Metal restriction also induces oxidative stress triggered, at least in part, by reduction in pyridoxin synthesis.
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Affiliation(s)
- Leandro do Prado Assunção
- Molecular Biology and Biochemistry Laboratory, Institute of Biological Sciences II, Federal University of Goias (UFG), Goiania, Brazil
| | - Dayane Moraes
- Molecular Biology and Biochemistry Laboratory, Institute of Biological Sciences II, Federal University of Goias (UFG), Goiania, Brazil
| | - Lucas Weba Soares
- Molecular Biology and Biochemistry Laboratory, Institute of Biological Sciences II, Federal University of Goias (UFG), Goiania, Brazil
| | - Mirelle Garcia Silva-Bailão
- Molecular Biology and Biochemistry Laboratory, Institute of Biological Sciences II, Federal University of Goias (UFG), Goiania, Brazil
| | - Janaina Gomes de Siqueira
- Molecular Biology and Biochemistry Laboratory, Institute of Biological Sciences II, Federal University of Goias (UFG), Goiania, Brazil
| | - Lilian Cristiane Baeza
- Laboratory of Experimental Microbiology, State University of Western Paraná (Unioeste), Cascavel, Brazil
| | - Sônia Nair Báo
- Microscopy and Microanalysis Laboratory, Institute of Biological Sciences, Brasília University (UnB), Brasilia, Brazil
| | - Célia Maria de Almeida Soares
- Molecular Biology and Biochemistry Laboratory, Institute of Biological Sciences II, Federal University of Goias (UFG), Goiania, Brazil
| | - Alexandre Melo Bailão
- Molecular Biology and Biochemistry Laboratory, Institute of Biological Sciences II, Federal University of Goias (UFG), Goiania, Brazil
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12
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Soares LW, Bailão AM, Soares CMDA, Bailão MGS. Zinc at the Host-Fungus Interface: How to Uptake the Metal? J Fungi (Basel) 2020; 6:jof6040305. [PMID: 33233335 PMCID: PMC7711662 DOI: 10.3390/jof6040305] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/11/2020] [Accepted: 11/12/2020] [Indexed: 12/31/2022] Open
Abstract
Zinc is an essential nutrient for all living organisms. However, firm regulation must be maintained since micronutrients also can be toxic in high concentrations. This notion is reinforced when we look at mechanisms deployed by our immune system, such as the use of chelators or membrane transporters that capture zinc, when threatened with pathogens, like fungi. Pathogenic fungi, on the other hand, also make use of a variety of transporters and specialized zinc captors to survive these changes. In this review, we sought to explain the mechanisms, grounded in experimental analysis and described to date, utilized by pathogenic fungi to maintain optimal zinc levels.
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13
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Kang S, Seo H, Moon HS, Kwon JH, Park YS, Yun CW. The Role of Zinc in Copper Homeostasis of Aspergillus fumigatus. Int J Mol Sci 2020; 21:ijms21207665. [PMID: 33081273 PMCID: PMC7593903 DOI: 10.3390/ijms21207665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 10/14/2020] [Accepted: 10/14/2020] [Indexed: 11/16/2022] Open
Abstract
Copper is an essential metal ion that performs many physiological functions in living organisms. Deletion of Afmac1, which is a copper-responsive transcriptional activator in A. fumigatus, results in a growth defect on aspergillus minimal medium (AMM). Interestingly, we found that zinc starvation suppressed the growth defect of the Δafmac1 strain on AMM. In addition, the growth defect of the Δafmac1 strain was recovered by copper supplementation or introduction of the CtrC gene into the Δafmac1 strain. However, chelation of copper by addition of BCS to AMM failed to recover the growth defect of the Δafmac1 strain. Through Northern blot analysis, we found that zinc starvation upregulated CtrC and CtrA2, which encode membrane copper transporters. Interestingly, we found that the conserved ZafA binding motif 5'-CAA(G)GGT-3' was present in the upstream region of CtrC and CtrA2 and that mutation of the binding motif led to failure of ZafA binding to the upstream region of CtrC and upregulation of CtrC expression under zinc starvation. Furthermore, the binding activity of ZafA to the upstream region of CtrC was inversely proportional to the zinc concentration, and copper inhibited the binding of ZafA to the upstream region of CtrC under a low zinc concentration. Taken together, these results suggest that ZafA upregulates copper metabolism by binding to the ZafA binding motif in the CtrC promoter region under low zinc concentration, thus regulating copper homeostasis. Furthermore, we found that copper and zinc interact in cells to maintain metal homeostasis.
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Affiliation(s)
| | | | | | | | | | - Cheol-Won Yun
- Correspondence: ; Tel.: +82-2-3290-3456; Fax: +82-2-927-9028
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14
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Eide DJ. Transcription factors and transporters in zinc homeostasis: lessons learned from fungi. Crit Rev Biochem Mol Biol 2020; 55:88-110. [PMID: 32192376 DOI: 10.1080/10409238.2020.1742092] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Zinc is an essential nutrient for all organisms because this metal serves as a critical structural or catalytic cofactor for many proteins. These zinc-dependent proteins are abundant in the cytosol as well as within organelles of eukaryotic cells such as the nucleus, mitochondria, endoplasmic reticulum, Golgi, and storage compartments such as the fungal vacuole. Therefore, cells need zinc transporters so that they can efficiently take up the metal and move it around within cells. In addition, because zinc levels in the environment can vary drastically, the activity of many of these transporters and other components of zinc homeostasis is regulated at the level of transcription by zinc-responsive transcription factors. Mechanisms of post-transcriptional control are also important for zinc homeostasis. In this review, the focus will be on our current knowledge of zinc transporters and their regulation by zinc-responsive transcription factors and other mechanisms in fungi because these organisms have served as useful paradigms of zinc homeostasis in all organisms. With this foundation, extension to other organisms will be made where warranted.
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Affiliation(s)
- David J Eide
- Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, USA
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15
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López‐Berges MS. ZafA-mediated regulation of zinc homeostasis is required for virulence in the plant pathogen Fusarium oxysporum. MOLECULAR PLANT PATHOLOGY 2020; 21:244-249. [PMID: 31750619 PMCID: PMC6988419 DOI: 10.1111/mpp.12891] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
During infection, soilborne fungal pathogens face limiting conditions of different metal ions, including zinc. The role of zinc homeostasis in fungal pathogenicity on plants remains poorly understood. Here it is shown that the transcription factor ZafA, orthologous to Saccharomyces cerevisiae Zap1, functions as a key regulator of zinc homeostasis and virulence in Fusarium oxysporum, a cross-kingdom pathogen that causes vascular wilt on more than 100 plant species and opportunistic infections in humans. Expression of zafA is induced under zinc-limiting conditions and repressed by zinc. Interestingly, zafA is markedly up-regulated during early stages of plant infection, suggesting that F. oxysporum must cope with limited availability of zinc. Deletion of zafA results in deactivation of high-affinity zinc transporters, leading to impaired growth under zinc deficiency. Fusarium oxysporum strains lacking ZafA are reduced in their capability to invade and kill tomato plants and the non-vertebrate animal model Galleria mellonella. Collectively, the results indicate that ZafA-mediated adaptation to zinc deficiency is required for full virulence of F. oxysporum on plant and animal hosts.
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Affiliation(s)
- Manuel S. López‐Berges
- Departamento de GenéticaCampus de Excelencia Internacional Agroalimentario (ceiA3)Universidad de Córdoba14071CórdobaSpain
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16
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Seo H, Kang S, Park YS, Yun CW. The Role of Zinc in Gliotoxin Biosynthesis of Aspergillus fumigatus. Int J Mol Sci 2019; 20:E6192. [PMID: 31817957 PMCID: PMC6940964 DOI: 10.3390/ijms20246192] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Revised: 12/04/2019] [Accepted: 12/04/2019] [Indexed: 12/21/2022] Open
Abstract
Zinc performs diverse physiological functions, and virtually all living organisms require zinc as an essential trace element. To identify the detailed function of zinc in fungal pathogenicity, we carried out cDNA microarray analysis using the model system of Aspergillus fumigatus, a fungal pathogen. From microarray analysis, we found that the genes involved in gliotoxin biosynthesis were upregulated when zinc was depleted, and the microarray data were confirmed by northern blot analysis. In particular, zinc deficiency upregulated the expression of GliZ, which encodes a Zn2-Cys6 binuclear transcription factor that regulates the expression of the genes required for gliotoxin biosynthesis. The production of gliotoxin was decreased in a manner inversely proportional to the zinc concentration, and the same result was investigated in the absence of ZafA, which is a zinc-dependent transcription activator. Interestingly, we found two conserved ZafA-binding motifs, 5'-CAAGGT-3', in the upstream region of GliZ on the genome and discovered that deletion of the ZafA-binding motifs resulted in loss of ZafA-binding activity; gliotoxin production was decreased dramatically, as demonstrated with a GliZ deletion mutant. Furthermore, mutation of the ZafA-binding motifs resulted in an increase in the conidial killing activity of human macrophage and neutrophil cells, and virulence was decreased in a murine model. Finally, transcriptomic analysis revealed that the expression of ZafA and GliZ was upregulated during phagocytosis by macrophages. Taken together, these results suggest that zinc plays an important role in the pathogenicity of A. fumigatus by regulating gliotoxin production during the phagocytosis pathway to overcome the host defense system.
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Affiliation(s)
| | | | | | - Cheol-Won Yun
- School of Life Sciences and Biotechnology, Korea University, Anam-dong, Sungbuk-gu, Seoul 02841, Korea; (H.S.); (S.K.); (Y.-S.P.)
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17
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Identification and characterization of the ZRT, IRT-like protein (ZIP) family genes reveal their involvement in growth and kojic acid production in Aspergillus oryzae. ACTA ACUST UNITED AC 2019; 46:1769-1780. [DOI: 10.1007/s10295-019-02236-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 09/11/2019] [Indexed: 12/31/2022]
Abstract
Abstract
The ZRT, IRT-like protein (ZIP) family exists in many species and plays an important role in many biological processes, but little is known about ZIP genes in Aspergillus oryzae. Here, 10 ZIP genes in A. oryzae were identified and these were classified into four groups based on phylogenetic analysis. The structures of these AoZip genes were determined, which indicated a great divergence of AoZip members from different groups. Synteny analysis revealed that AoZip7, AoZip8, and AoZip10 are conserved among Aspergillus species. We also found that the promoter regions of AoZip2, AoZip7, AoZip8, and AoZip10 contain multiple conserved response elements. Expression analysis revealed that AoZips exhibited different expression patterns in response to different metal treatments. Moreover, overexpression and RNA-interference (RNAi) of AoZip2 led to a decrease in mycelium growth diameter and inhibited conidia formation. AoZip2 overexpression and RNAi strains showed distinct sensitivity to severely Zn/Mn-depleted stress. In addition, kojic acid production was markedly lower in AoZip2 overexpression and RNAi strains than in the control strains, and the expression of kojA, kojR, and kojT was down-regulated in AoZip2 overexpression and RNAi strains. This study provides new insights into our understanding of ZIP genes and lays a foundation for further investigation of their roles in Aspergillus oryzae.
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18
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Wilson D, Deepe GS. The intersection of host and fungus through the zinc lens. Curr Opin Microbiol 2019; 52:35-40. [PMID: 31132743 DOI: 10.1016/j.mib.2019.04.008] [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: 03/07/2019] [Revised: 04/17/2019] [Accepted: 04/22/2019] [Indexed: 12/19/2022]
Abstract
In this review, we summarize data regarding the influence of zinc on host defenses to human pathogenic fungi and how the fungus acquires zinc to sustain biological functions. Mammals have evolved several extracellular and intracellular mechanisms to withhold zinc from the fungus. Specific immune cells release zinc binding proteins such as calprotectin to capture the metal and deny it to the fungus. Intracellularly, several zinc binding proteins such as metallothioneins starve the fungus of zinc. The net result in both situations is depriving the fungus of a crucial micronutrient. To combat this struggle, fungi have developed means to capture zinc and store it. The mechanisms of transport for various fungi are discussed herein.
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Affiliation(s)
- Duncan Wilson
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - George S Deepe
- Division of Infectious Diseases, Department of Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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19
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Vicentefranqueira R, Leal F, Marín L, Sánchez CI, Calera JA. The interplay between zinc and iron homeostasis in
Aspergillus fumigatus
under zinc‐replete conditions relies on the iron‐mediated regulation of alternative transcription units of
zafA
and the basal amount of the ZafA zinc‐responsiveness transcription factor. Environ Microbiol 2019; 21:2787-2808. [DOI: 10.1111/1462-2920.14618] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 04/03/2019] [Indexed: 12/27/2022]
Affiliation(s)
- Rocío Vicentefranqueira
- Instituto de Biología Funcional y Genómica (IBFG‐CSIC)Universidad de Salamanca Salamanca Spain
| | - Fernando Leal
- Instituto de Biología Funcional y Genómica (IBFG‐CSIC)Universidad de Salamanca Salamanca Spain
- Departamento de Microbiología y GenéticaUniversidad de Salamanca Salamanca Spain
| | - Laura Marín
- Instituto de Biología Funcional y Genómica (IBFG‐CSIC)Universidad de Salamanca Salamanca Spain
| | - Clara Inés Sánchez
- Instituto de Biología Funcional y Genómica (IBFG‐CSIC)Universidad de Salamanca Salamanca Spain
| | - José Antonio Calera
- Instituto de Biología Funcional y Genómica (IBFG‐CSIC)Universidad de Salamanca Salamanca Spain
- Departamento de Microbiología y GenéticaUniversidad de Salamanca Salamanca Spain
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20
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Clark HL, Minns MS, Sun Y, de Jesus T, Ghannoum MG, Pearlman E. Atovaquone Impairs Growth of Aspergillus and Fusarium Keratitis Isolates by Modulating Mitochondrial Function and Zinc Homeostasis. Invest Ophthalmol Vis Sci 2018; 59:1589-1598. [PMID: 29625485 PMCID: PMC5863689 DOI: 10.1167/iovs.17-22585] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Purpose Aspergillus and Fusarium molds cause blinding corneal infections as a consequence of ocular trauma and in association with contact lens wear. As these fungi require zinc for fungal growth, we examined the effect of atovaquone, a ubiquinone analog that disrupts zinc homeostasis, on fungal growth in vitro and in vivo. Methods In vitro: Aspergillus and Fusarium germinating conidia were incubated overnight with atovaquone, and hyphal growth was measured by fluorimetry. In vivo: C57BL/6 mouse corneas were infected with Aspergillus or Fusarium conidia. Atovaquone was added topically and corneal opacification and fungal growth were quantified. Results Atovaquone has antifungal activity against Aspergillus and Fusarium clinical isolates, with Fusarium species being more sensitive to atovaquone than Aspergillus species. Atovaquone also reduced labile intracellular zinc levels and increased the sensitivity of Aspergillus to metal shock. Atovaquone reduced vacuolar acidification, which regulates storage of intracellular free zinc, and also acted synergistically with voriconazole and itraconazole to kill hyphae. Furthermore, mitochondrial potential and ATP production were reduced in both Aspergillus and Fusarium following atovaquone treatment. Finally, topical application of atovaquone to the ocular surface significantly inhibited fungal growth and corneal opacification in murine models of fungal keratitis. Conclusions These studies demonstrate that atovaquone has pronounced in vitro and in vivo antifungal activity against filamentous fungi by disrupting both metal homeostasis and mitochondrial function, and therefore has potential as a novel antifungal agent.
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Affiliation(s)
- Heather L Clark
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States.,Department of Ophthalmology, University of California Irvine, Irvine, California, United States.,Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States
| | - Martin S Minns
- Department of Ophthalmology, University of California Irvine, Irvine, California, United States.,Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States
| | - Yan Sun
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States
| | - Tristan de Jesus
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States
| | - Mahmoud G Ghannoum
- Department of Dermatology, Case Western Reserve University, Cleveland, Ohio, United States
| | - Eric Pearlman
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio, United States.,Department of Ophthalmology, University of California Irvine, Irvine, California, United States.,Department of Physiology and Biophysics, University of California Irvine, Irvine, California, United States
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21
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The Transcription Factor ZafA Regulates the Homeostatic and Adaptive Response to Zinc Starvation in Aspergillus fumigatus. Genes (Basel) 2018; 9:genes9070318. [PMID: 29949939 PMCID: PMC6070888 DOI: 10.3390/genes9070318] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 06/20/2018] [Accepted: 06/20/2018] [Indexed: 12/20/2022] Open
Abstract
One of the most important features that enables Aspergillus fumigatus to grow within a susceptible individual and to cause disease is its ability to obtain Zn2+ ions from the extremely zinc-limited environment provided by host tissues. Zinc uptake from this source in A. fumigatus relies on ZIP transporters encoded by the zrfA, zrfB and zrfC genes. The expression of these genes is tightly regulated by the ZafA transcription factor that regulates zinc homeostasis and is essential for A. fumigatus virulence. We combined the use of microarrays, Electrophoretic Mobility Shift Assays (EMSA) analyses, DNase I footprinting assays and in silico tools to better understand the regulation of the homeostatic and adaptive response of A. fumigatus to zinc starvation. We found that under zinc-limiting conditions, ZafA functions mainly as a transcriptional activator through binding to a zinc response sequence located in the regulatory regions of its target genes, although it could also function as a repressor of a limited number of genes. In addition to genes involved in the homeostatic response to zinc deficiency, ZafA also influenced, either directly or indirectly, the expression of many other genes. It is remarkable that the expression of many genes involved in iron uptake and ergosterol biosynthesis is strongly reduced under zinc starvation, even though only the expression of some of these genes appeared to be influenced directly or indirectly by ZafA. In addition, it appears to exist in A. fumigatus a zinc/iron cross-homeostatic network to allow the adaptation of the fungus to grow in media containing unbalanced Zn:Fe ratios. The adaptive response to oxidative stress typically linked to zinc starvation was also mediated by ZafA, as was the strong induction of genes involved in gliotoxin biosynthesis and self-protection against endogenous gliotoxin. This study has expanded our knowledge about the regulatory and metabolic changes displayed by A. fumigatus in response to zinc starvation and has helped us to pinpoint new ZafA target genes that could be important for fungal pathogens to survive and grow within host tissues and, hence, for virulence.
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22
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Cai Z, Du W, Zhang Z, Guan L, Zeng Q, Chai Y, Dai C, Lu L. TheAspergillus fumigatustranscription factor AceA is involved not only in Cu but also in Zn detoxification through regulating transporters CrpA and ZrcA. Cell Microbiol 2018; 20:e12864. [DOI: 10.1111/cmi.12864] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/03/2018] [Accepted: 05/08/2018] [Indexed: 01/03/2023]
Affiliation(s)
- Zhendong Cai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Wenlong Du
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Zheng Zhang
- Department of Dermatology, Jinling Hospital, School of Medicine; Nanjing University; Nanjing China
| | - Luyu Guan
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Qiuqiong Zeng
- Department of Dermatology, Jinling Hospital, School of Medicine; Nanjing University; Nanjing China
| | - Yanfei Chai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Chuanchao Dai
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
| | - Ling Lu
- Jiangsu Key Laboratory for Microbes and Functional Genomics, Jiangsu Engineering and Technology Research Center for Microbiology; College of Life Sciences; Nanjing Normal University; Nanjing China
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23
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Garcia Silva-Bailão M, Lobato Potenciano da Silva K, Raniere Borges dos Anjos L, de Sousa Lima P, de Melo Teixeira M, Maria de Almeida Soares C, Melo Bailão A. Mechanisms of copper and zinc homeostasis in pathogenic black fungi. Fungal Biol 2018; 122:526-537. [DOI: 10.1016/j.funbio.2017.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Revised: 12/01/2017] [Accepted: 12/04/2017] [Indexed: 02/08/2023]
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24
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A Novel Polyaminocarboxylate Compound To Treat Murine Pulmonary Aspergillosis by Interfering with Zinc Metabolism. Antimicrob Agents Chemother 2018; 62:AAC.02510-17. [PMID: 29632009 DOI: 10.1128/aac.02510-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 03/31/2018] [Indexed: 12/28/2022] Open
Abstract
Aspergillus fumigatus can cause pulmonary aspergillosis in immunocompromised patients and is associated with a high mortality rate due to a lack of reliable treatment options. This opportunistic pathogen requires zinc in order to grow and cause disease. Novel compounds that interfere with fungal zinc metabolism may therefore be of therapeutic interest. We screened chemical libraries containing 59,223 small molecules using a resazurin assay that compared their effects on an A. fumigatus wild-type strain grown under zinc-limiting conditions and on a zinc transporter knockout strain grown under zinc-replete conditions to identify compounds affecting zinc metabolism. After a first screen, 116 molecules were selected whose inhibitory effects on fungal growth were further tested by using luminescence assays and hyphal length measurements to confirm their activity, as well as by toxicity assays on HeLa cells and mice. Six compounds were selected following a rescreening, of which two were pyrazolones, two were porphyrins, and two were polyaminocarboxylates. All three groups showed good in vitro activity, but only one of the polyaminocarboxylates was able to significantly improve the survival of immunosuppressed mice suffering from pulmonary aspergillosis. This two-tier screening approach led us to the identification of a novel small molecule with in vivo fungicidal effects and low murine toxicity that may lead to the development of new treatment options for fungal infections by administration of this compound either as a monotherapy or as part of a combination therapy.
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25
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Crawford AC, Lehtovirta-Morley LE, Alamir O, Niemiec MJ, Alawfi B, Alsarraf M, Skrahina V, Costa ACBP, Anderson A, Yellagunda S, Ballou ER, Hube B, Urban CF, Wilson D. Biphasic zinc compartmentalisation in a human fungal pathogen. PLoS Pathog 2018; 14:e1007013. [PMID: 29727465 PMCID: PMC5955600 DOI: 10.1371/journal.ppat.1007013] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 05/16/2018] [Accepted: 04/09/2018] [Indexed: 12/14/2022] Open
Abstract
Nutritional immunity describes the host-driven manipulation of essential micronutrients, including iron, zinc and manganese. To withstand nutritional immunity and proliferate within their hosts, pathogenic microbes must express efficient micronutrient uptake and homeostatic systems. Here we have elucidated the pathway of cellular zinc assimilation in the major human fungal pathogen Candida albicans. Bioinformatics analysis identified nine putative zinc transporters: four cytoplasmic-import Zip proteins (Zrt1, Zrt2, Zrt3 and orf19.5428) and five cytoplasmic-export ZnT proteins (orf19.1536/Zrc1, orf19.3874, orf19.3769, orf19.3132 and orf19.52). Only Zrt1 and Zrt2 are predicted to localise to the plasma membrane and here we demonstrate that Zrt2 is essential for C. albicans zinc uptake and growth at acidic pH. In contrast, ZRT1 expression was found to be highly pH-dependent and could support growth of the ZRT2-null strain at pH 7 and above. This regulatory paradigm is analogous to the distantly related pathogenic mould, Aspergillus fumigatus, suggesting that pH-adaptation of zinc transport may be conserved in fungi and we propose that environmental pH has shaped the evolution of zinc import systems in fungi. Deletion of C. albicans ZRT2 reduced kidney fungal burden in wild type, but not in mice lacking the zinc-chelating antimicrobial protein calprotectin. Inhibition of zrt2Δ growth by neutrophil extracellular traps was calprotectin-dependent. This suggests that, within the kidney, C. albicans growth is determined by pathogen-Zrt2 and host-calprotectin. As well as serving as an essential micronutrient, zinc can also be highly toxic and we show that C. albicans deals with this potential threat by rapidly compartmentalising zinc within vesicular stores called zincosomes. In order to understand mechanistically how this process occurs, we created deletion mutants of all five ZnT-type transporters in C. albicans. Here we show that, unlike in Saccharomyces cerevisiae, C. albicans Zrc1 mediates zinc tolerance via zincosomal zinc compartmentalisation. This novel transporter was also essential for virulence and liver colonisation in vivo. In summary, we show that zinc homeostasis in a major human fungal pathogen is a multi-stage process initiated by Zrt1/Zrt2-cellular import, followed by Zrc1-dependent intracellular compartmentalisation.
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Affiliation(s)
- Aaron C. Crawford
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Laura E. Lehtovirta-Morley
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, United Kingdom
| | - Omran Alamir
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Maria J. Niemiec
- Department of Clinical Microbiology, Umeå Centre for Microbial Research and Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
- Research Group Microbial Immunology, Leibniz Institute for Natural Product Research and Infection Biology–Hans Knoell Institute, Jena, Germany
- Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
| | - Bader Alawfi
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Mohammad Alsarraf
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Volha Skrahina
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology–Hans Knoell Institute, Jena, Germany
| | - Anna C. B. P. Costa
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Andrew Anderson
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
| | - Sujan Yellagunda
- Department of Clinical Microbiology, Umeå Centre for Microbial Research and Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
| | - Elizabeth R. Ballou
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- Institute of Microbiology and Infection, and School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Bernhard Hube
- Center for Sepsis Control and Care (CSCC), University Hospital, Jena, Germany
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology–Hans Knoell Institute, Jena, Germany
- Friedrich Schiller University, Jena, Germany
| | - Constantin F. Urban
- Department of Clinical Microbiology, Umeå Centre for Microbial Research and Molecular Infection Medicine Sweden, Umeå University, Umeå, Sweden
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology at the University of Aberdeen, Aberdeen Fungal Group, Institute of Medical Sciences, Foresterhill, Aberdeen, United Kingdom
- * E-mail:
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26
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Novel Zinc-Attenuating Compounds as Potent Broad-Spectrum Antifungal Agents with In Vitro and In Vivo Efficacy. Antimicrob Agents Chemother 2018; 62:AAC.02024-17. [PMID: 29439980 PMCID: PMC5923171 DOI: 10.1128/aac.02024-17] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 02/04/2018] [Indexed: 12/23/2022] Open
Abstract
An increase in the incidence of rare but hard-to-treat invasive fungal pathogens as well as resistance to the currently available antifungal drugs calls for new broad-spectrum antifungals with a novel mechanism of action. Here we report the identification and characterization of two novel zinc-attenuating compounds, ZAC307 and ZAC989, which exhibit broad-spectrum in vitro antifungal activity and in vivo efficacy in a fungal kidney burden candidiasis model. The compounds were identified serendipitously as part of a drug discovery process aimed at finding novel inhibitors of the fungal plasma membrane proton ATPase Pma1. Based on their structure, we hypothesized that they might act as zinc chelators. Indeed, both fluorescence-based affinity determination and potentiometric assays revealed these compounds, subsequently termed zinc-attenuating compounds (ZACs), to have strong affinity for zinc, and their growth inhibitory effects on Candida albicans and Aspergillus fumigatus could be inactivated by the addition of exogenous zinc to fungal growth media. We determined the ZACs to be fungistatic, with a low propensity for resistance development. Gene expression analysis suggested that the ZACs interfere negatively with the expression of genes encoding the major components of the A. fumigatus zinc uptake system, thus supporting perturbance of zinc homeostasis as the likely mode of action. With demonstrated in vitro and in vivo antifungal activity, low propensity for resistance development, and a novel mode of action, the ZACs represent a promising new class of antifungal compounds, and their advancement in a drug development program is therefore warranted.
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27
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Leonhardt T, Sácký J, Kotrba P. Functional analysis RaZIP1 transporter of the ZIP family from the ectomycorrhizal Zn-accumulating Russula atropurpurea. Biometals 2018; 31:255-266. [DOI: 10.1007/s10534-018-0085-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2017] [Accepted: 02/10/2018] [Indexed: 11/28/2022]
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28
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López-Díaz C, Rahjoo V, Sulyok M, Ghionna V, Martín-Vicente A, Capilla J, Di Pietro A, López-Berges MS. Fusaric acid contributes to virulence of Fusarium oxysporum on plant and mammalian hosts. MOLECULAR PLANT PATHOLOGY 2018; 19:440-453. [PMID: 28093838 PMCID: PMC6638071 DOI: 10.1111/mpp.12536] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 12/30/2016] [Accepted: 01/10/2017] [Indexed: 05/03/2023]
Abstract
Fusaric acid (FA) is amongst the oldest identified secondary metabolites produced by Fusarium species, known for a long time to display strong phytotoxicity and moderate toxicity to animal cells; however, the cellular targets of FA and its function in fungal pathogenicity remain unknown. Here, we investigated the role of FA in Fusarium oxysporum, a soil-borne cross-kingdom pathogen that causes vascular wilt on more than 100 plant species and opportunistic infections in humans. Targeted deletion of fub1, encoding a predicted orthologue of the polyketide synthase involved in FA biosynthesis in F. verticillioides and F. fujikuroi, abolished the production of FA and its derivatives in F. oxysporum. We further showed that the expression of fub1 was positively controlled by the master regulator of secondary metabolism LaeA and the alkaline pH regulator PacC through the modulation of chromatin accessibility at the fub1 locus. FA exhibited strong phytotoxicity on tomato plants, which was rescued by the exogenous supply of copper, iron or zinc, suggesting a possible function of FA as a chelating agent of these metal ions. Importantly, the severity of vascular wilt symptoms on tomato plants and the mortality of immunosuppressed mice were significantly reduced in fub1Δ mutants and fully restored in the complemented strains. Collectively, these results provide new insights into the regulation and mode of action of FA, as well as on the function of this phytotoxin during the infection process of F. oxysporum.
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Affiliation(s)
- Cristina López-Díaz
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, Campus de Excelencia Agroalimentario (ceiA3), Córdoba, E-14071, Spain
| | - Vahid Rahjoo
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, Campus de Excelencia Agroalimentario (ceiA3), Córdoba, E-14071, Spain
| | - Michael Sulyok
- Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life Sciences, Vienna (BOKU), Konrad Lorenz Str. 20, Tulln, 3430, Austria
| | - Veronica Ghionna
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, Campus de Excelencia Agroalimentario (ceiA3), Córdoba, E-14071, Spain
| | - Adela Martín-Vicente
- Mycology Unit, Medical School, Universitat Rovira i Virgili, IISPV, Reus, 43204, Spain
| | - Javier Capilla
- Mycology Unit, Medical School, Universitat Rovira i Virgili, IISPV, Reus, 43204, Spain
| | - Antonio Di Pietro
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, Campus de Excelencia Agroalimentario (ceiA3), Córdoba, E-14071, Spain
| | - Manuel S López-Berges
- Departamento de Genética, Facultad de Ciencias, Universidad de Córdoba, Campus de Excelencia Agroalimentario (ceiA3), Córdoba, E-14071, Spain
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Gerwien F, Skrahina V, Kasper L, Hube B, Brunke S. Metals in fungal virulence. FEMS Microbiol Rev 2018; 42:4562650. [PMID: 29069482 PMCID: PMC5812535 DOI: 10.1093/femsre/fux050] [Citation(s) in RCA: 142] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 10/19/2017] [Indexed: 12/25/2022] Open
Abstract
Metals are essential for life, and they play a central role in the struggle between infecting microbes and their hosts. In fact, an important aspect of microbial pathogenesis is the 'nutritional immunity', in which metals are actively restricted (or, in an extended definition of the term, locally enriched) by the host to hinder microbial growth and virulence. Consequently, fungi have evolved often complex regulatory networks, uptake and detoxification systems for essential metals such as iron, zinc, copper, nickel and manganese. These systems often differ fundamentally from their bacterial counterparts, but even within the fungal pathogens we can find common and unique solutions to maintain metal homeostasis. Thus, we here compare the common and species-specific mechanisms used for different metals among different fungal species-focusing on important human pathogens such as Candida albicans, Aspergillus fumigatus or Cryptococcus neoformans, but also looking at model fungi such as Saccharomyces cerevisiae or A. nidulans as well-studied examples for the underlying principles. These direct comparisons of our current knowledge reveal that we have a good understanding how model fungal pathogens take up iron or zinc, but that much is still to learn about other metals and specific adaptations of individual species-not the least to exploit this knowledge for new antifungal strategies.
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Affiliation(s)
- Franziska Gerwien
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Volha Skrahina
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Lydia Kasper
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Bernhard Hube
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
| | - Sascha Brunke
- Department Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology– Hans Knoell Institute, 07745 Jena, Germany
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Liu H, Xu W, Solis NV, Woolford C, Mitchell AP, Filler SG. Functional convergence of gliP and aspf1 in Aspergillus fumigatus pathogenicity. Virulence 2018; 9:1062-1073. [PMID: 30052103 PMCID: PMC6086310 DOI: 10.1080/21505594.2018.1482182] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 05/25/2018] [Indexed: 10/28/2022] Open
Abstract
Gliotoxin contributes to the virulence of the fungus Aspergillus fumigatus in non-neutropenic mice that are immunosuppressed with corticosteroids. To investigate how the absence of gliotoxin affects both the fungus and the host, we used a nanoString nCounter to analyze their transcriptional responses during pulmonary infection of a non-neutropenic host with a gliotoxin-deficient ΔgliP mutant. We found that the ΔgliP mutation led to increased expression of aspf1, which specifies a secreted ribotoxin. Prior studies have shown that aspf1, like gliP, is not required for virulence in a neutropenic infection model, but its role in a non-neutropenic infection model has not been fully investigated. To investigate the functional significance of this up-regulation of aspf1, a Δaspf1 single mutant and a Δaspf1 ΔgliP double mutant were constructed. Both Δaspf1 and ΔgliP single mutants had reduced lethality in non-neutropenic mice, and a Δaspf1 ΔgliP double mutant had a greater reduction in lethality than either single mutant. Analysis of mice infected with these mutants indicated that the presence of gliP is associated with massive apoptosis of leukocytes at the foci of infection and inhibition of chemokine production. Also, the combination of gliP and aspf1 is associated with suppression of CXCL1 chemokine expression. Thus, aspf1 contributes to A. fumigatus pathogenicity in non-neutropenic mice and its up-regulation in the ΔgliP mutant may partially compensate for the absence of gliotoxin. ABBREVIATIONS PAS: periodic acid-Schiff; PBS: phosphate buffered saline; ROS: reactive oxygen species; TUNEL: terminal deoxynucleotidyl transferase dUTP nick-end labeling.
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Affiliation(s)
- Hong Liu
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Wenjie Xu
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Norma V. Solis
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
| | - Carol Woolford
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Aaron P. Mitchell
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA
| | - Scott G. Filler
- Division of Infectious Diseases, Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Torrance, CA, USA
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Sherrington SL, Kumwenda P, Kousser C, Hall RA. Host Sensing by Pathogenic Fungi. ADVANCES IN APPLIED MICROBIOLOGY 2017; 102:159-221. [PMID: 29680125 DOI: 10.1016/bs.aambs.2017.10.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The ability to cause disease extends from the ability to grow within the host environment. The human host provides a dynamic environment to which fungal pathogens must adapt to in order to survive. The ability to grow under a particular condition (i.e., the ability to grow at mammalian body temperature) is considered a fitness attribute and is essential for growth within the human host. On the other hand, some environmental conditions activate signaling mechanisms resulting in the expression of virulence factors, which aid pathogenicity. Therefore, pathogenic fungi have evolved fitness and virulence attributes to enable them to colonize and infect humans. This review highlights how some of the major pathogenic fungi respond and adapt to key environmental signals within the human host.
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Affiliation(s)
- Sarah L Sherrington
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Pizga Kumwenda
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Courtney Kousser
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Rebecca A Hall
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom.
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Lehtovirta-Morley LE, Alsarraf M, Wilson D. Pan-Domain Analysis of ZIP Zinc Transporters. Int J Mol Sci 2017; 18:E2631. [PMID: 29211002 PMCID: PMC5751234 DOI: 10.3390/ijms18122631] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Revised: 12/01/2017] [Accepted: 12/01/2017] [Indexed: 12/13/2022] Open
Abstract
The ZIP (Zrt/Irt-like protein) family of zinc transporters is found in all three domains of life. However, little is known about the phylogenetic relationship amongst ZIP transporters, their distribution, or their origin. Here we employed phylogenetic analysis to explore the evolution of ZIP transporters, with a focus on the major human fungal pathogen, Candida albicans. Pan-domain analysis of bacterial, archaeal, fungal, and human proteins revealed a complex relationship amongst the ZIP family members. Here we report (i) a eukaryote-wide group of cellular zinc importers, (ii) a fungal-specific group of zinc importers having genetic association with the fungal zincophore, and, (iii) a pan-kingdom supercluster made up of two distinct subgroups with orthologues in bacterial, archaeal, and eukaryotic phyla.
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Affiliation(s)
- Laura E Lehtovirta-Morley
- Aberdeen Fungal Group, Medical Research Council Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK.
- School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, UK.
| | - Mohammad Alsarraf
- Aberdeen Fungal Group, Medical Research Council Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK.
| | - Duncan Wilson
- Aberdeen Fungal Group, Medical Research Council Centre for Medical Mycology, Institute of Medical Sciences, University of Aberdeen, Aberdeen AB25 2ZD, UK.
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Zhang X, Dai P, Gao Y, Gong X, Cui H, Jin Y, Zhang Y. Transcriptome sequencing and analysis of zinc-uptake-related genes in Trichophyton mentagrophytes. BMC Genomics 2017; 18:888. [PMID: 29157209 PMCID: PMC5697147 DOI: 10.1186/s12864-017-4284-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 11/07/2017] [Indexed: 12/19/2022] Open
Abstract
Background Trichophyton mentagrophytes is an important zoonotic dermatophytic (ringworm) pathogen; causing severe skin infection in humans and other animals worldwide. Fortunately, commonly used fungal skin disease prevention and treatment measures are relatively simple. However, T. mentagrophytes is primarily studied at the epidemiology and drug efficacy research levels, yet current study has been unable to meet the needs of clinical medicine. Zinc is a crucial trace element for the growth and reproduction of fungi and other microorganisms. The metal ions coordinate within a variety of proteins to form zinc finger proteins, which perform many vital biological functions. Zinc transport regulatory networks have not been resolved in T. mentagrophytes. The T. mentagrophytes transcriptome will allow us to discover new genes, particularly those genes involved in zinc uptake. Result We found T. mentagrophytes growth to be restricted by zinc deficiency; natural T. mentagrophytes growth requires zinc ions. T. Mentagrophytes must acquire zinc ions for growth and development. The transcriptome of T. mentagrophytes was sequenced by using Illumina HiSeq™ 2000 technology and the de novo assembly of the transcriptome was performed by using the Trinity method, and functional annotation was analyzed. We got 10,751 unigenes. The growth of T. mentagrophytes is severely inhibited and there were many genes showing significant up regulation and down regulation respectively in T. mentagrophytes when zinc deficiency. Zinc deficiency can affect the expression of multiple genes of T. mentagrophytes. The effect of the zinc deficiency could be recovered in the normal medium. And we finally found the zinc-responsive activating factor (ZafA) and speculated that 4 unigenes are zinc transporters. We knocked ZafA gene by ATMT transformation in T. mentagrophytes, the result showed that ZafA gene is very important for the growth and the generation of conidia in T. mentagrophytes. The expression of 4 zinc transporter genes is potentially regulated by the zinc-responsive activating factor. The data of this study is also sufficient to be used as a support to study T. mentagrophytes. Conclusion We reported the first large transcriptome study carried out in T. mentagrophytes where we have compared physiological and transcriptional responses to zinc deficiency, and analyzed the expression of genes involved in zinc uptake. The study also produced high-resolution digital profiles of global genes expression relating to T. mentagrophytes growth. Electronic supplementary material The online version of this article (10.1186/s12864-017-4284-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xinke Zhang
- The College of Veterinary Medicine of the Northwest Agriculture and Forestry University, No. 3 Taicheng Road, Yangling, Shaanxi, People's Republic of China
| | - Pengxiu Dai
- The College of Veterinary Medicine of the Northwest Agriculture and Forestry University, No. 3 Taicheng Road, Yangling, Shaanxi, People's Republic of China
| | - Yongping Gao
- The College of Veterinary Medicine of the Northwest Agriculture and Forestry University, No. 3 Taicheng Road, Yangling, Shaanxi, People's Republic of China
| | - Xiaowen Gong
- The College of Veterinary Medicine of the Northwest Agriculture and Forestry University, No. 3 Taicheng Road, Yangling, Shaanxi, People's Republic of China
| | - Hao Cui
- The College of Veterinary Medicine of the Northwest Agriculture and Forestry University, No. 3 Taicheng Road, Yangling, Shaanxi, People's Republic of China
| | - Yipeng Jin
- Clinical Department, College of Veterinary Medicine, China Agricultural University, Beijing, People's Republic of China
| | - Yihua Zhang
- The College of Veterinary Medicine of the Northwest Agriculture and Forestry University, No. 3 Taicheng Road, Yangling, Shaanxi, People's Republic of China.
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Li J, Sang H, Guo H, Popko JT, He L, White JC, Parkash Dhankher O, Jung G, Xing B. Antifungal mechanisms of ZnO and Ag nanoparticles to Sclerotinia homoeocarpa. NANOTECHNOLOGY 2017; 28:155101. [PMID: 28294107 DOI: 10.1088/1361-6528/aa61f3] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Fungicides have extensively been used to effectively combat fungal diseases on a range of plant species, but resistance to multiple active ingredients has developed in pathogens such as Sclerotinia homoeocarpa, the causal agent of dollar spot on cool-season turfgrasses. Recently, ZnO and Ag nanoparticles (NPs) have received increased attention due to their antimicrobial activities. In this study, the NPs' toxicity and mechanisms of action were investigated as alternative antifungal agents against S. homoeocarpa isolates that varied in their resistance to demethylation inhibitor (DMI) fungicides. S. homoeocarpa isolates were treated with ZnO NPs and ZnCl2 (25-400 μg ml-1) and Ag NPs and AgNO3 (5-100 μg ml-1) to test antifungal activity of the NPs and ions. The mycelial growth of S. homoeocarpa isolates regardless of their DMI sensitivity was significantly inhibited on ZnO NPs (≥200 μg ml-1), Ag NPs (≥25 μg ml-1), Zn2+ ions (≥200 μg ml-1), and Ag+ ions (≥10 μg ml-1) amended media. Expression of stress response genes, glutathione S-transferase (Shgst1) and superoxide dismutase 2 (ShSOD2), was significantly induced in the isolates by exposure to the NPs and ions. In addition, a significant increase in the nucleic acid contents of fungal hyphae, which may be due to stress response, was observed upon treatment with Ag NPs using Raman spectroscopy. We further observed that a zinc transporter (Shzrt1) might play an important role in accumulating ZnO and Ag NPs into the cells of S. homoeocarpa due to overexpression of Shzrt1 significantly induced by ZnO or Ag NPs within 3 h of exposure. Yeast mutants complemented with Shzrt1 became more sensitive to ZnO and Ag NPs as well as Zn2+ and Ag+ ions than the control strain and resulted in increased Zn or Ag content after exposure. This is the first report of involvement of the zinc transporter in the accumulation of Zn and Ag from NP exposure in filamentous plant pathogenic fungi. Understanding the molecular mechanisms of NPs' antifungal activities will be useful in developing effective management strategies to control important pathogenic fungal diseases.
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Affiliation(s)
- Junli Li
- Stockbridge School of Agriculture, University of Massachusetts, 161 Holdsworth Way, Amherst, MA 01003, United States of America. School of Chemistry, Chemical Engineering and Life Science, Wuhan University of Technology, Wuhan 430070, People's Republic of China
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Malavia D, Crawford A, Wilson D. Nutritional Immunity and Fungal Pathogenesis: The Struggle for Micronutrients at the Host-Pathogen Interface. Adv Microb Physiol 2017; 70:85-103. [PMID: 28528652 DOI: 10.1016/bs.ampbs.2017.01.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
All living organisms require certain micronutrients such as iron, zinc, manganese and copper for cellular function and growth. For human pathogens however, the maintenance of metal ion homeostasis is particularly challenging. This is because the mammalian host actively enforces extremes of micronutrient availability on potential microbial invaders-processes collectively termed nutritional immunity. The role of iron sequestration in controlling microbial infections is well established and, more recently, the importance of other metals including zinc, manganese and copper has been recognised. In this chapter, we explore the nutritional immune mechanisms that defend the human body against fungal infections and the strategies that these important pathogens exploit to counteract nutritional immunity and thrive in the infected host.
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Affiliation(s)
- Dhara Malavia
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, United Kingdom
| | - Aaron Crawford
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, United Kingdom
| | - Duncan Wilson
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, United Kingdom.
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36
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Krappmann S. How to invade a susceptible host: cellular aspects of aspergillosis. Curr Opin Microbiol 2016; 34:136-146. [PMID: 27816786 DOI: 10.1016/j.mib.2016.10.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/12/2016] [Accepted: 10/17/2016] [Indexed: 02/07/2023]
Abstract
Diseases caused by Aspergillus spp. and in particular A. fumigatus are manifold and affect individuals suffering from immune dysfunctions, among them immunocompromised ones. The determinants of whether the encounter of a susceptible host with infectious propagules of this filamentous saprobe results in infection have been characterized to a limited extent. Several cellular characteristics of A. fumigatus that have evolved in its natural environment contribute to its virulence, among them general traits as well as particular ones that affect interaction with the mammalian host. Among the latter, conidial constituents, cell wall components, secreted proteins as well as extrolites shape the tight interaction of A. fumigatus with the host milieu and also contribute to evasion from immune surveillance.
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Affiliation(s)
- Sven Krappmann
- Institute of Microbiology - Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen and Friedrich-Alexander University Erlangen-Nürnberg, Wasserturmstr. 3/5, D-91054 Erlangen, Germany.
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Administration of Zinc Chelators Improves Survival of Mice Infected with Aspergillus fumigatus both in Monotherapy and in Combination with Caspofungin. Antimicrob Agents Chemother 2016; 60:5631-9. [PMID: 27401578 DOI: 10.1128/aac.00324-16] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2016] [Accepted: 07/01/2016] [Indexed: 12/19/2022] Open
Abstract
Aspergillus fumigatus can infect immunocompromised patients, leading to high mortality rates due to the lack of reliable treatment options. This pathogen requires uptake of zinc from host tissues in order to successfully grow and cause virulence. Reducing the availability of that micronutrient could help treat A. fumigatus infections. In this study, we examined the in vitro effects of seven chelators using a bioluminescent strain of A. fumigatus 1,10-Phenanthroline and N,N,N',N'-tetrakis(2-pyridylmethyl)ethane-1,2-diamine (TPEN) proved to be the chelators most effective at inhibiting fungal growth. Intraperitoneal administration of either phenanthroline or TPEN resulted in a significant improvement in survival and decrease of weight loss and fungal burden for immunosuppressed mice intranasally infected with A. fumigatus In vitro both chelators had an indifferent effect when employed in combination with caspofungin. The use of TPEN in combination with caspofungin also significantly increased survival compared to that when using these drugs individually. Our results suggest that zinc chelation may be a valid strategy for dealing with A. fumigatus infections and that both phenanthroline and TPEN could potentially be used either independently or in combination with caspofungin, indicating that their use in combination with other antifungal treatments might also be applicable.
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Dade J, DuBois JC, Pasula R, Donnell AM, Caruso JA, Smulian AG, Deepe GS. HcZrt2, a zinc responsive gene, is indispensable for the survival of Histoplasma capsulatum in vivo. Med Mycol 2016; 54:865-75. [PMID: 27335059 DOI: 10.1093/mmy/myw045] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2016] [Accepted: 03/20/2016] [Indexed: 12/25/2022] Open
Abstract
Histoplasma capsulatum (Hc) exists in the soil and is capable of adapting to the shift in environment during infection to ensure survival. Yeast encounter a restrictive host environment low in nutrients such as zinc. In this study we functionally analyzed a putative zinc regulated transporter, HcZrt2, in zinc limiting conditions by complementation of HcZrt2 and gene knockdown through RNA interference (RNAi). Complementation analysis demonstrated HcZrt2's ability to functionally replace the characterized Saccharomyces cerevisiae zinc plasma membrane transporters Zrt1 and Zrt2 in zinc deficient medium. Gene silencing revealed that HcZrt2 is essential for growth in zinc deficient medium and plays a role in zinc accumulation. Fungal burden was reduced in mice infected with HcZrt2 silenced strains compared to a control strain. Sixty-seven percent of mice infected with a lethal dose of HcZrt2-RNAi#1 survived, and 100% of mice infected with HcZrt2-RNAi#2 withstood lethal infection. Our data suggest that HcZrt2 is a vital part of zinc homeostasis and essential for the pathogenesis of histoplasmosis.
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Affiliation(s)
- Jessica Dade
- Department of Molecular Genetics, Biochemistry and Microbiology
| | - Juwen C DuBois
- Department of Internal Medicine, Division of Infectious Diseases
| | - Rajamouli Pasula
- Department of Internal Medicine, Division of Infectious Diseases
| | - Anna M Donnell
- Department of Chemistry University of Cincinnati, Cincinnati OH 45267
| | - Joseph A Caruso
- Department of Chemistry University of Cincinnati, Cincinnati OH 45267
| | - A George Smulian
- Department of Internal Medicine, Division of Infectious Diseases Cincinnati VA Medical Center, Cincinnati Ohio
| | - George S Deepe
- Department of Internal Medicine, Division of Infectious Diseases Cincinnati VA Medical Center, Cincinnati Ohio
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Do E, Hu G, Caza M, Kronstad JW, Jung WH. The ZIP family zinc transporters support the virulence of Cryptococcus neoformans. Med Mycol 2016; 54:605-15. [PMID: 27118799 DOI: 10.1093/mmy/myw013] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 02/24/2016] [Indexed: 11/14/2022] Open
Abstract
Zinc is an essential element in living organisms and a cofactor for various metalloproteins. To disseminate and survive, a pathogenic microbe must obtain zinc from the host, which is an environment with extremely limited zinc availability. In this study, we investigated the roles of the ZIP family zinc transporters Zip1 and Zip2 in the human pathogenic fungus Cryptococcus neoformans Zip1 and Zip2 are homologous to Zrt1 and Zrt2 of the model fungus, Saccharomyces cerevisiae, respectively. We found that the expression of ZIP1 was regulated by the zinc concentration in the environment. Furthermore, the mutant lacking ZIP1 displayed a severe growth defect under zinc-limited conditions, while the mutant lacking ZIP2 displayed normal growth. Inductively coupled plasma-atomic emission spectroscopy analysis showed that the absence of Zip1 expression significantly reduced total cellular zinc levels relative to that in the wild type, while overexpression of Zip1 was associated with increased cellular zinc levels. These findings suggested that Zip1 plays roles in zinc uptake in C. neoformans We also constructed a Zip1-FLAG fusion protein and found, by immunofluorescence, not only that the protein was localized to the periphery implying it is a membrane transporter, but also that the protein was N-glycosylated. Furthermore, the mutant lacking ZIP1 showed attenuated virulence in a murine inhalation model of cryptococcosis and reduced survival within murine macrophages. Overall, our data suggest that Zip1 plays essential roles in zinc transport and the virulence of C. neoformans.
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Affiliation(s)
- Eunsoo Do
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea
| | - Guanggan Hu
- The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver BC, V6T 1Z4, Canada
| | - Mélissa Caza
- The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver BC, V6T 1Z4, Canada
| | - James W Kronstad
- The Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver BC, V6T 1Z4, Canada
| | - Won Hee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong, 456-756, Republic of Korea
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Alcazar-Fuoli L, Buitrago M, Gomez-Lopez A, Mellado E. An alternative host model of a mixed fungal infection by azole susceptible and resistant Aspergillus spp strains. Virulence 2016; 6:376-84. [PMID: 26065322 DOI: 10.1080/21505594.2015.1025192] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Aspergillus fumigatus is the most common mold involved in human infections. However, the number of non-fumigatus species able to cause disease is continuously increasing. Among them, Aspergillus lentulus is reported in hematological and cystic fibrosis patients and in those treated with corticosteroids. A. lentulus differs from A. fumigatus in some clinically relevant aspects such as virulence and antifungal susceptibility, showing high MICs to most antifungals. Previous studies proved that A. lentulus was pathogenic in immunocompromised mice, although the course of the infection was delayed compared to A. fumigatus. These differences could explain why A. lentulus is mostly found in mixed infections with A. fumigatus challenging the diagnosis and treatment. We used the alternative model host Galleria mellonella to compare virulence, host interaction, fungal burden and antifungal response when larvae were infected with A. fumigatus or A. lentulus alone, and with a mixture of both species. A. lentulus was pathogenic in G. mellonella but infected larvae did not respond to therapeutic doses of voriconazole. We were able to simultaneously detect A. fumigatus and A. lentulus by a multiplex Nested Real Time PCR (MN-PCR). Comparative analysis of larvae histological sections showed melanization of both species but presented a different pattern of immune response by haemocytes. Analysis of fungal burden and histology showed that A. lentulus survived in the G. mellonella despite the antifungal treatment in single and mixed infections. We conclude that the simultaneous presence of antifungal susceptible and resistant Aspergillus species would likely complicate the management of these infections.
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Affiliation(s)
- L Alcazar-Fuoli
- a Mycology Reference Laboratory; Centro Nacional de Microbiologia ; Instituto de Salud Carlos III ; Madrid , Spain
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41
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Clark HL, Jhingran A, Sun Y, Vareechon C, de Jesus Carrion S, Skaar EP, Chazin WJ, Calera JA, Hohl TM, Pearlman E. Zinc and Manganese Chelation by Neutrophil S100A8/A9 (Calprotectin) Limits Extracellular Aspergillus fumigatus Hyphal Growth and Corneal Infection. THE JOURNAL OF IMMUNOLOGY 2015; 196:336-44. [PMID: 26582948 DOI: 10.4049/jimmunol.1502037] [Citation(s) in RCA: 112] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 10/19/2015] [Indexed: 01/09/2023]
Abstract
Calprotectin, a heterodimer of S100A8 and S100A9, is an abundant neutrophil protein that possesses antimicrobial activity primarily because of its ability to chelate zinc and manganese. In the current study, we showed that neutrophils from calprotectin-deficient S100A9(-/-) mice have an impaired ability to inhibit Aspergillus fumigatus hyphal growth in vitro and in infected corneas in a murine model of fungal keratitis; however, the ability to inhibit hyphal growth was restored in S100A9(-/-) mice by injecting recombinant calprotectin. Furthermore, using recombinant calprotectin with mutations in either the Zn and Mn binding sites or the Mn binding site alone, we show that both zinc and manganese binding are necessary for calprotectin's antihyphal activity. In contrast to hyphae, we found no role for neutrophil calprotectin in uptake or killing of intracellular A. fumigatus conidia either in vitro or in a murine model of pulmonary aspergillosis. We also found that an A. fumigatus ∆zafA mutant, which demonstrates deficient zinc transport, exhibits impaired growth in infected corneas and following incubation with neutrophils or calprotectin in vitro as compared with wild-type. Collectively, these studies demonstrate a novel stage-specific susceptibility of A. fumigatus to zinc and manganese chelation by neutrophil-derived calprotectin.
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Affiliation(s)
- Heather L Clark
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH 44106; Department of Ophthalmology, University of California, Irvine, Irvine, CA 92697; Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697
| | - Anupam Jhingran
- Infectious Disease Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10065
| | - Yan Sun
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH 44106
| | - Chairut Vareechon
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH 44106
| | - Steven de Jesus Carrion
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH 44106
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232; Veterans Affairs Tennessee Valley Healthcare System, Nashville, TN 37212
| | - Walter J Chazin
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN 37232; Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232; and
| | - José Antonio Calera
- Instituto de Biología Funcional y Genómica, Centro Mixto del Consejo Superior de Investigaciones Científicas y Universidad de Salamanca, 37002 Salamanca, Spain
| | - Tobias M Hohl
- Infectious Disease Service, Department of Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY 10065
| | - Eric Pearlman
- Department of Ophthalmology and Visual Science, Case Western Reserve University, Cleveland, OH 44106; Department of Ophthalmology, University of California, Irvine, Irvine, CA 92697; Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA 92697;
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42
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Jung WH. The Zinc Transport Systems and Their Regulation in Pathogenic Fungi. MYCOBIOLOGY 2015; 43:179-83. [PMID: 26539032 PMCID: PMC4630422 DOI: 10.5941/myco.2015.43.3.179] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 08/13/2015] [Accepted: 08/18/2015] [Indexed: 05/15/2023]
Abstract
Zinc is an essential micronutrient required for many enzymes that play essential roles in a cell. It was estimated that approximately 3% of the total cellular proteins are required for zinc for their functions. Zinc has long been considered as one of the key players in host-pathogen interactions. The host sequesters intracellular zinc by utilizing multiple cellular zinc importers and exporters as a means of nutritional immunity. To overcome extreme zinc limitation within the host environment, pathogenic microbes have successfully evolved a number of mechanisms to secure sufficient concentrations of zinc for their survival and pathogenesis. In this review, we briefly discuss the zinc uptake systems and their regulation in the model fungus Saccharomyces cerevisiae and in major human pathogenic fungi such as Aspergillus fumigatus, Candida albicans, and Cryptococcus gattii.
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Affiliation(s)
- Won Hee Jung
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Korea
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43
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Crawford A, Wilson D. Essential metals at the host-pathogen interface: nutritional immunity and micronutrient assimilation by human fungal pathogens. FEMS Yeast Res 2015; 15:fov071. [PMID: 26242402 PMCID: PMC4629794 DOI: 10.1093/femsyr/fov071] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2015] [Indexed: 12/23/2022] Open
Abstract
The ability of pathogenic microorganisms to assimilate sufficient nutrients for growth within their hosts is a fundamental requirement for pathogenicity. However, certain trace nutrients, including iron, zinc and manganese, are actively withheld from invading pathogens in a process called nutritional immunity. Therefore, successful pathogenic species must have evolved specialized mechanisms in order to adapt to the nutritionally restrictive environment of the host and cause disease. In this review, we discuss recent advances which have been made in our understanding of fungal iron and zinc acquisition strategies and nutritional immunity against fungal infections, and explore the mechanisms of micronutrient uptake by human pathogenic fungi. The human body tightly sequesters essential micronutrients, restricting their access to invading microorganisms, and pathogenic species must counteract this action of ‘nutritional immunity’.
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Affiliation(s)
- Aaron Crawford
- Aberdeen Fungal Group, School of Medical Sciences, Aberdeen AB25 2ZD, UK
| | - Duncan Wilson
- Aberdeen Fungal Group, School of Medical Sciences, Aberdeen AB25 2ZD, UK
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Csr1/Zap1 Maintains Zinc Homeostasis and Influences Virulence in Candida dubliniensis but Is Not Coupled to Morphogenesis. EUKARYOTIC CELL 2015; 14:661-70. [PMID: 26002718 PMCID: PMC4486669 DOI: 10.1128/ec.00078-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 05/09/2015] [Indexed: 01/10/2023]
Abstract
The supply and intracellular homeostasis of trace metals are essential for every living organism. Therefore, the struggle for micronutrients between a pathogen and its host is an important determinant in the infection process. In this work, we focus on the acquisition of zinc by Candida dubliniensis, an emerging pathogen closely related to Candida albicans. We show that the transcription factor Csr1 is essential for C. dubliniensis to regulate zinc uptake mechanisms under zinc limitation: it governs the expression of the zinc transporter genes ZRT1, ZRT2, and ZRT3 and of the zincophore gene PRA1. Exclusively, artificial overexpression of ZRT2 partially rescued the growth defect of a csr1Δ/Δ mutant in a zinc-restricted environment. Importantly, we found that, in contrast to what is seen in C. albicans, Csr1 (also called Zap1) is not a major regulator of dimorphism in C. dubliniensis. However, although a csr1Δ/Δ strain showed normal germ tube formation, we detected a clear attenuation in virulence using an embryonated chicken egg infection model. We conclude that, unlike in C. albicans, Csr1 seems to be a virulence factor of C. dubliniensis that is not coupled to filamentation but is strongly linked to zinc acquisition during pathogenesis.
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Vicentefranqueira R, Amich J, Laskaris P, Ibrahim-Granet O, Latgé JP, Toledo H, Leal F, Calera JA. Targeting zinc homeostasis to combat Aspergillus fumigatus infections. Front Microbiol 2015; 6:160. [PMID: 25774155 PMCID: PMC4343018 DOI: 10.3389/fmicb.2015.00160] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 02/11/2015] [Indexed: 11/13/2022] Open
Abstract
Aspergillus fumigatus is able to invade and grow in the lungs of immunosuppressed individuals and causes invasive pulmonary aspergillosis. The concentration of free zinc in living tissues is much lower than that required for optimal fungal growth in vitro because most of it is tightly bound to proteins. To obtain efficiently zinc from a living host A. fumigatus uses the zinc transporters ZrfA, ZrfB, and ZrfC. The ZafA transcriptional regulator induces the expression of all these transporters and is essential for virulence. Thus, ZafA could be targeted therapeutically to inhibit fungal growth. The ZrfC transporter plays the major role in zinc acquisition from the host whereas ZrfA and ZrfB rather have a supplementary role to that of ZrfC. In addition, only ZrfC enables A. fumigatus to overcome the inhibitory effect of calprotectin, which is an antimicrobial Zn/Mn-chelating protein synthesized and released by neutrophils within the fungal abscesses of immunosuppressed non-leucopenic animals. Hence, fungal survival in these animals would be undermined upon blocking therapeutically the function of ZrfC. Therefore, both ZafA and ZrfC have emerged as promising targets for the discovery of new antifungals to treat Aspergillus infections.
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Affiliation(s)
- Rocío Vicentefranqueira
- Instituto de Biología Funcional y Genómica, Centro Mixto del Consejo Superior de Investigaciones Científicas y Universidad de Salamanca , Salamanca, Spain ; Departamento de Microbiología y Genética, Universidad de Salamanca , Salamanca, Spain
| | - Jorge Amich
- Instituto de Biología Funcional y Genómica, Centro Mixto del Consejo Superior de Investigaciones Científicas y Universidad de Salamanca , Salamanca, Spain ; Departamento de Microbiología y Genética, Universidad de Salamanca , Salamanca, Spain
| | - Paris Laskaris
- Unité de Recherche Cytokines and Inflammation, Institut Pasteur , Paris, France
| | | | - Jean P Latgé
- Unité des Aspergillus, Institut Pasteur , Paris, France
| | - Héctor Toledo
- Instituto de Biología Funcional y Genómica, Centro Mixto del Consejo Superior de Investigaciones Científicas y Universidad de Salamanca , Salamanca, Spain ; Departamento de Microbiología y Genética, Universidad de Salamanca , Salamanca, Spain
| | - Fernando Leal
- Instituto de Biología Funcional y Genómica, Centro Mixto del Consejo Superior de Investigaciones Científicas y Universidad de Salamanca , Salamanca, Spain ; Departamento de Microbiología y Genética, Universidad de Salamanca , Salamanca, Spain
| | - José A Calera
- Instituto de Biología Funcional y Genómica, Centro Mixto del Consejo Superior de Investigaciones Científicas y Universidad de Salamanca , Salamanca, Spain ; Departamento de Microbiología y Genética, Universidad de Salamanca , Salamanca, Spain
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46
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Amich J, Calera JA. Zinc acquisition: a key aspect in Aspergillus fumigatus virulence. Mycopathologia 2014; 178:379-85. [PMID: 24947168 DOI: 10.1007/s11046-014-9764-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 05/28/2014] [Indexed: 10/25/2022]
Abstract
Zinc is an essential micronutrient required for the growth of all microorganisms. To grow in the lungs of a susceptible patient Aspergillus fumigatus must obtain zinc from the surrounding tissues. The concentration of Zn(2+) ions in living tissues is much lower than that required for optimal fungal growth in vitro because most of them are tightly bound to proteins at the physiological pH. However, A. fumigatus has several zinc transporters (ZrfA, ZrfB and ZrfC) that enable it to uptake zinc efficiently under the extreme zinc-limiting conditions provided by a susceptible host. The ZafA transcriptional regulator induces the expression of these transporters and is essential for virulence. ZrfC is required for fungal growth within the host tissues, whereas ZrfA and ZrfB play an accessory role. The zinc-scavenging capacity of ZrfC relies on its unusually long N-terminus. In addition, ZrfC also enables A. fumigatus to overcome the inhibitory effect of calprotectin, which is an antimicrobial Zn/Mn-chelating protein synthesized in high amounts by neutrophils, even in immunosuppressed non-leucopenic animals. In summary, the regulation of zinc homeostasis and zinc acquisition could be promising targets for the discovery and development of a new generation of antifungals for the treatment of invasive pulmonary aspergillosis.
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Affiliation(s)
- Jorge Amich
- Instituto de Biología Funcional y Genómica (IBFG) (centro mixto CSIC-Universidad de Salamanca) y Departamento de Microbiología y Genética, Universidad de Salamanca, Edificio IBFG, Lab. P1.10. C/Zacarías González nº 2, 37007, Salamanca, Spain
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Ding C, Hu G, Jung WH, Kronstad JW. Essential Metals in Cryptococcus neoformans: Acquisition and Regulation. CURRENT FUNGAL INFECTION REPORTS 2014. [DOI: 10.1007/s12281-014-0180-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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48
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Vignesh KS, Landero Figueroa JA, Porollo A, Caruso JA, Deepe GS. Zinc sequestration: arming phagocyte defense against fungal attack. PLoS Pathog 2013; 9:e1003815. [PMID: 24385902 PMCID: PMC3873440 DOI: 10.1371/journal.ppat.1003815] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Affiliation(s)
- Kavitha Subramanian Vignesh
- Department of Molecular Genetics, Biochemistry, Microbiology and Immunology, University of Cincinnati, Cincinnati, Ohio, United States of America
- Division of Infectious Diseases, College of Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Julio A. Landero Figueroa
- University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - Aleksey Porollo
- Divisions of Rheumatology and Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio, United States of America
| | - Joseph A. Caruso
- University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, Ohio, United States of America
| | - George S. Deepe
- Division of Infectious Diseases, College of Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- Veterans Affairs Hospital, Cincinnati, Ohio, United States of America
- * E-mail:
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49
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Amich J, Vicentefranqueira R, Mellado E, Ruiz-Carmuega A, Leal F, Calera JA. The ZrfC alkaline zinc transporter is required for Aspergillus fumigatus virulence and its growth in the presence of the Zn/Mn-chelating protein calprotectin. Cell Microbiol 2013; 16:548-64. [PMID: 24245710 DOI: 10.1111/cmi.12238] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 11/05/2013] [Accepted: 11/11/2013] [Indexed: 01/08/2023]
Abstract
Aspergillus fumigatus can invade the lungs of immunocompromised individuals causing a life-threatening disease called invasive pulmonary aspergillosis (IPA). To grow in the lungs, A. fumigatus obtains from the host all nutrients, including zinc. In living tissues, however, most zinc is tightly bound to zinc-binding proteins. Moreover, during infection the bioavailability of zinc can be further decreased by calprotectin, an antimicrobial Zn/Mn-chelating protein that is released by neutrophils in abscesses. Nevertheless, A. fumigatus manages to uptake zinc from and grow within the lungs of susceptible individuals. Thus, in this study we investigated the role of the zrfA, zrfB and zrfC genes, encoding plasma membrane zinc transporters, in A. fumigatus virulence. We showed that zrfC is essential for virulence in the absence of zrfA and zrfB, which contribute to fungal pathogenesis to a lesser extent than zrfC and are dispensable for virulence in the presence of zrfC. The special ability of ZrfC to scavenge and uptake zinc efficiently from lungtissue depended on its N-terminus, which is absent in the ZrfA and ZrfB transporters. In addition, under Zn- and/or Mn-limiting conditions zrfC enables A. fumigatus to grow in the presence of calprotectin, which is detected in fungal abscesses of non-leucopenic animals. This study extends our knowledge about the pathobiology of A. fumigatus and suggests that fungal zinc uptake could be a promising target for new antifungals.
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Affiliation(s)
- Jorge Amich
- Instituto de Biología Funcional y Genómica (IBFG), centro mixto del Consejo Superior de Investigaciones Científicas y Universidad de Salamanca, Edificio IBFG, Lab. P1.10. C/Zacarías González n°2, 37007, Salamanca, Spain
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50
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Staats CC, Kmetzsch L, Schrank A, Vainstein MH. Fungal zinc metabolism and its connections to virulence. Front Cell Infect Microbiol 2013; 3:65. [PMID: 24133658 PMCID: PMC3796257 DOI: 10.3389/fcimb.2013.00065] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2013] [Accepted: 09/26/2013] [Indexed: 12/03/2022] Open
Abstract
Zinc is a ubiquitous metal in all life forms, as it is a structural component of the almost 10% of eukaryotic proteins, which are called zinc-binding proteins. In zinc-limiting conditions such as those found during infection, pathogenic fungi activate the expression of several systems to enhance the uptake of zinc. These systems include ZIP transporters (solute carrier 39 family) and secreted zincophores, which are proteins that are able to chelate zinc. The expression of some fungal zinc uptake systems are regulated by a master regulator (Zap1), first characterized in the yeast Saccharomyces cerevisiae. In this review, we highlight features of zinc uptake and metabolism in human fungal pathogens and aspects of the relationship between proper zinc metabolism and the expression of virulence factors and adaptation to the host habitat.
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Affiliation(s)
- Charley C Staats
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil ; Departamento de Biologia Molecular e Biotecnologia, Universidade Federal do Rio Grande do Sul Porto Alegre, Brazil
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