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Boone CHT, Gutzmann DJ, Kramer JJ, Urbin SD, Navarathna DH, Atkin AL, Nickerson KW. Micronutrient availability alters Candida albicans growth and farnesol accumulation: implications for studies using RPMI-1640. Microbiol Spectr 2024:e0157124. [PMID: 39315785 DOI: 10.1128/spectrum.01571-24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2024] [Accepted: 08/19/2024] [Indexed: 09/25/2024] Open
Abstract
Science is challenging because we do not know what we do not know. Commercial chemicals are often marketed with >99% purity, but 0.5-1% impurity can impact results and cloud data interpretation. We recently developed an assay for farnesol and aromatic fusel alcohols from Candida albicans. During proof-of-concept experiments using RPMI-1640 growth media, the buffering compound was switched from MOPS obtained from Acros Organics to MOPS obtained from Sigma-Aldrich, both labeled 99% + purity. We observed a twofold decrease in growth, along with a three- to fivefold increase in farnesol production per cell upon the switch. ICP-MS showed that trace Mn(II) was present in Acros MOPS but absent in Sigma MOPS. Optimal growth was achieved by the addition of Mn(II), Zn(II), and Fe(II). We established upper and lower limits for Fe(II), Zn(II), Cu(II), and Mn(II) that allowed similar growth and then assessed 16 different mineral combinations in RPMI-1640 base media. The results show an increased production of farnesol and the aromatic fusel alcohols when Zn(II) is abundant, and a further increase in the aromatic fusel alcohols when both Fe(II) and Zn(II) are abundant. Finally, antifungal susceptibility testing displayed no significant difference between RPMI/MOPS with and without mineral supplementation. Supplemental Mn(II) was most needed for cell growth, while supplemental Zn(II) was most needed for the production of farnesol and the aromatic fusel alcohols. To avoid these artifacts due to metal contamination, we now use a modified RPMI supplemented with 1 mg/ L of Cu(II), Zn(II), Mn(II), and Fe(II). IMPORTANCE The dimorphic fungus Candida albicans is a major opportunistic pathogen of humans. RPMI-1640 is a chemically defined growth medium commonly used with C. albicans. We identified over 32,000 publications with keywords RPMI and C. albicans. Additionally, Antifungal Susceptibility Testing (AFST) protocols in the United States (CLSI) and Europe (EUCAST) utilize RPMI as a base media to assess drug efficacy against clinical fungal isolates. RPMI contains many nutrients but no added trace metals. We found that the growth characteristics with RPMI were dependent on which MOPS buffer was chosen and the contamination of that buffer by trace levels of Mn(II) and Zn(II). Added Mn(II) was most needed for cell growth while added Zn(II) was most needed for secretion of farnesol and other signaling molecules.
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Affiliation(s)
- Cory H T Boone
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Daniel J Gutzmann
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Jaxon J Kramer
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Shyanne D Urbin
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | | | - Audrey L Atkin
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
| | - Kenneth W Nickerson
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska, USA
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2
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Rahman MA, Bissa M, Silva de Castro I, Helmold Hait S, Stamos JD, Bhuyan F, Hunegnaw R, Sarkis S, Gutowska A, Doster MN, Moles R, Hoang T, Miller Jenkins LM, Appella E, Venzon DJ, Choo-Wosoba H, Cardozo T, Baum MM, Appella DH, Robert-Guroff M, Franchini G. Vaccine plus microbicide effective in preventing vaginal SIV transmission in macaques. Nat Microbiol 2023; 8:905-918. [PMID: 37024617 PMCID: PMC10159859 DOI: 10.1038/s41564-023-01353-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 03/02/2023] [Indexed: 04/08/2023]
Abstract
The human immunodeficiency virus epidemic continues in sub-Saharan Africa, and particularly affects adolescent girls and women who have limited access to antiretroviral therapy. Here we report that the risk of vaginal simian immunodeficiency virus (SIV)mac251 acquisition is reduced by more than 90% using a combination of a vaccine comprising V1-deleted (V2 enhanced) SIV envelope immunogens with topical treatment of the zinc-finger inhibitor SAMT-247. Following 14 weekly intravaginal exposures to the highly pathogenic SIVmac251, 80% of a cohort of 20 macaques vaccinated and treated with SAMT-247 remained uninfected. In an arm of 18 vaccinated-only animals without microbicide, 40% of macaques remained uninfected. The combined SAMT-247/vaccine regimen was significantly more effective than vaccination alone. By analysing immune correlates of protection, we show that, by increasing zinc availability, SAMT-247 increases natural killer cytotoxicity and monocyte efferocytosis, and decreases T-cell activation to augment vaccine-induced protection.
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Affiliation(s)
- Mohammad Arif Rahman
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD, USA
| | - Massimiliano Bissa
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD, USA
| | | | - Sabrina Helmold Hait
- Section on Immune Biology of Retroviral Infection, National Cancer Institute, Bethesda, MD, USA
| | - James D Stamos
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD, USA
| | - Farzana Bhuyan
- Translational Autoinflammatory Diseases Section, Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Ruth Hunegnaw
- Section on Immune Biology of Retroviral Infection, National Cancer Institute, Bethesda, MD, USA
| | - Sarkis Sarkis
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD, USA
| | - Anna Gutowska
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD, USA
| | - Melvin N Doster
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD, USA
| | - Ramona Moles
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD, USA
| | - Tanya Hoang
- Section on Immune Biology of Retroviral Infection, National Cancer Institute, Bethesda, MD, USA
| | - Lisa M Miller Jenkins
- Collaborative Protein Technology Resource, Laboratory of Cell Biology, National Cancer Institute, Bethesda, MD, USA
| | - Ettore Appella
- Chemical Immunology Section, National Cancer Institute, Bethesda, MD, USA
| | - David J Venzon
- Biostatistics and Data Management Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Hyoyoung Choo-Wosoba
- Biostatistics and Data Management Section, Center for Cancer Research, National Cancer Institute, Bethesda, MD, USA
| | - Timothy Cardozo
- New York University School of Medicine, NYU Langone Health, New York, NY, USA
| | - Marc M Baum
- Oak Crest Institute of Science, Monrovia, CA, USA
| | - Daniel H Appella
- Synthetic Bioactive Molecules Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA
| | - Marjorie Robert-Guroff
- Section on Immune Biology of Retroviral Infection, National Cancer Institute, Bethesda, MD, USA
| | - Genoveffa Franchini
- Animal Models and Retroviral Vaccines Section, National Cancer Institute, Bethesda, MD, USA.
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3
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Wehmeier S, Morrison E, Plato A, Raab A, Feldmann J, Bedekovic T, Wilson D, Brand AC. Multi trace element profiling in pathogenic and non-pathogenic fungi. Fungal Biol 2020; 124:516-524. [PMID: 32389315 PMCID: PMC7232024 DOI: 10.1016/j.funbio.2020.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/25/2020] [Accepted: 03/03/2020] [Indexed: 12/14/2022]
Abstract
Maintaining appropriate levels of trace elements during infection of a host is essential for microbial pathogenicity. Here we compared the uptake of 10 trace elements from 3 commonly-used laboratory media by 3 pathogens, Candida albicans, Cryptococcus neoformans and Aspergillus fumigatus, and a model yeast, Saccharomyces cerevisiae. The trace element composition of the yeasts, C. albicans, C. neoformans and S. cerevisiae, grown in rich (YPD) medium, differed primarily in P, S, Fe, Zn and Co. Speciation analysis of the intracellular fraction, which indicates the size of the organic ligands with which trace elements are complexed, showed that the ligands for S were similar in the three fungi but there were significant differences in binding partners for Fe and Zn between C. neoformans and S.cerevisiae. The profile for Cu varied across the 3 yeast species. In a comparison of C. albicans and A. fumigatus hyphae, the former showed higher Fe, Cu, Zn and Mn, while A. fumigatus contained higher P, S Ca and Mo. Washing C. albicans cells with the cell-impermeable chelator, EGTA, depleted 50–90 % of cellular Ca, suggesting that a large proportion of this cation is stored in the cell wall. Treatment with the cell wall stressor, Calcofluor White (CFW), alone had little effect on the elemental profile whilst combined Ca + CFW stress resulted in high cellular Cu and very high Ca. Together our data enhance our understanding of trace element uptake by pathogenic fungi and provide evidence for the cell wall as an important storage organelle for Ca.
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Affiliation(s)
- Silvia Wehmeier
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Emma Morrison
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Anthony Plato
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Andrea Raab
- TESLA, School of Natural and Computing Sciences, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, UK
| | - Jörg Feldmann
- TESLA, School of Natural and Computing Sciences, University of Aberdeen, Meston Walk, Aberdeen AB24 3UE, UK
| | - Tina Bedekovic
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK; Medical Research Council Centre for Medical Mycology at the University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Duncan Wilson
- Medical Research Council Centre for Medical Mycology at the University of Exeter, Stocker Road, Exeter EX4 4QD, UK
| | - Alexandra C Brand
- School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK; Medical Research Council Centre for Medical Mycology at the University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
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4
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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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5
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Ruytinx J, Kafle A, Usman M, Coninx L, Zimmermann SD, Garcia K. Micronutrient transport in mycorrhizal symbiosis; zinc steals the show. FUNGAL BIOL REV 2020. [DOI: 10.1016/j.fbr.2019.09.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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6
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Bird AJ, Wilson S. Zinc homeostasis in the secretory pathway in yeast. Curr Opin Chem Biol 2020; 55:145-150. [PMID: 32114317 DOI: 10.1016/j.cbpa.2020.01.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 12/14/2019] [Accepted: 01/26/2020] [Indexed: 01/20/2023]
Abstract
It is estimated that up to 10% of proteins in eukaryotes require zinc for their function. Although the majority of these proteins are located in the nucleus and cytosol, a small subset is secreted from cells or is located within an intracellular compartment. As many of these compartmentalized metalloproteins fold to their native state and bind their zinc cofactor inside an organelle, cells require mechanisms to maintain supply of zinc to these compartments even under conditions of zinc deficiency. At the same time, intracellular compartments can also be the site for storing zinc ions, which then can be mobilized when needed. In this review, we highlight insight that has been obtained from yeast models about how zinc homeostasis is maintained in the secretory pathway and vacuole.
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Affiliation(s)
- Amanda J Bird
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA; Department of Human Sciences, The Ohio State University, Columbus, OH, 43210, USA; Center for RNA Biology, The Ohio State University, Columbus, OH, 43210, USA.
| | - Stevin Wilson
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, 43210, USA
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7
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Marszałek I, Goch W, Bal W. Ternary Zn(II) Complexes of Fluorescent Zinc Probes Zinpyr-1 and Zinbo-5 with the Low Molecular Weight Component of Exchangeable Cellular Zinc Pool. Inorg Chem 2019; 58:14741-14751. [PMID: 31646867 DOI: 10.1021/acs.inorgchem.9b02419] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The intracellular exchangeable Zn(II) is usually measured with synthetic fluorescent zinc sensors. 4',5'-Bis[bis(2-pyridylmethyl)aminomethyl]-2',7'-dichlorofluorescein (Zinpyr-1) is a sensor containing the fluorescein platform and a duplicated chelating unit. Its advantages include brightness and a relatively high affinity for Zn(II), Kd = 0.7 nM. 2-(4,5-Dimethoxy-2-hydroxyphenyl)-4-(2-pyridylmethyl)aminomethylbenzoxazole (Zinbo-5) is a member of a growing family of ratiometric synthetic Zn(II) probes, offering a possibility to determine Zn(II) concentration independently of the sensor concentration. Cells, however, contain high, millimolar or nearly millimolar concentrations of low molecular weight ligands (LMWLs) capable of binding Zn(II) ions. Previously, we demonstrated that such LMWLs can perturb the performance of some fluorescent zinc sensors by competition and formation of ternary Zn(sensor) (LMWL) complexes. Here we tested Zinpyr-1 and Zinbo-5 in this respect. Despite structural differences, both sensors formed such ternary complexes. We determined their stability constants CKtern and performed numerical simulations of Zn(II) distributions at physiological concentrations of selected LMWLs. Glutamic acid was found to provide the strongest ternary complexes with either of the studied sensors. Zn(Zinpyr-1)(Glu) was an absolutely dominant Zn(II)/Zinpyr-1 species (more than 96% of the exchangeable Zn(II)), and Zn(Zinbo-5)(Glu) was the most abundant one (more than 40%) in these simulations. Our results indicate that under cellular conditions these sensors are able to report Zn(II) complexed to LMWLs rather than free Zn2+ ions. On the other hand, the specific affinity of Zn(Zinpyr-1) and Zn(Zinbo-5) for Glu creates interesting opportunities for determining glutamic acid in biological samples.
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Affiliation(s)
- Ilona Marszałek
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
| | - Wojciech Goch
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland.,Faculty of Pharmacy , Medical University of Warsaw , Banacha 1 , 02-091 Warsaw , Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics , Polish Academy of Sciences , Pawińskiego 5a , 02-106 Warsaw , Poland
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8
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Coninx L, Smisdom N, Kohler A, Arnauts N, Ameloot M, Rineau F, Colpaert JV, Ruytinx J. SlZRT2 Encodes a ZIP Family Zn Transporter With Dual Localization in the Ectomycorrhizal Fungus Suillus luteus. Front Microbiol 2019; 10:2251. [PMID: 31681189 PMCID: PMC6797856 DOI: 10.3389/fmicb.2019.02251] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 09/17/2019] [Indexed: 11/13/2022] Open
Abstract
Ectomycorrhizal (ECM) fungi are important root symbionts of trees, as they can have significant effects on the nutrient status of plants. In polluted environments, particular ECM fungi can protect their host tree from Zn toxicity by restricting the transfer of Zn while securing supply of essential nutrients. However, mechanisms and regulation of cellular Zn homeostasis in ECM fungi are largely unknown, and it remains unclear how ECM fungi affect the Zn status of their host plants. This study focuses on the characterization of a ZIP (Zrt/IrtT-like protein) transporter, SlZRT2, in the ECM fungus Suillus luteus, a common root symbiont of young pine trees. SlZRT2 is predicted to encode a plasma membrane-located Zn importer. Heterologous expression of SlZRT2 in yeast mutants with impaired Zn uptake resulted in a minor impact on cellular Zn accumulation and growth. The SlZRT2 gene product showed a dual localization and was detected at the plasma membrane and perinuclear region. S. luteus ZIP-family Zn uptake transporters did not show the potential to induce trehalase activity in yeast and to function as Zn sensors. In response to excess environmental Zn, gene expression analysis demonstrated a rapid but minor and transient decrease in SlZRT2 transcript level. In ECM root tips, the gene is upregulated. Whether this regulation is due to limited Zn availability at the fungal-plant interface or to developmental processes is unclear. Altogether, our results suggest a function for SlZRT2 in cellular Zn redistribution from the ER next to a putative role in Zn uptake in S. luteus.
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Affiliation(s)
- Laura Coninx
- Centre for Environmental Sciences, Environmental Biology, Hasselt University, Diepenbeek, Belgium
| | - Nick Smisdom
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - Annegret Kohler
- Laboratoire d’Excellence ARBRE, Institut National de la Recherche Agronomique, UMR 1136 INRA/Université de Lorraine Interactions Arbres/Microorganismes, Champenoux, France
| | - Natascha Arnauts
- Centre for Environmental Sciences, Environmental Biology, Hasselt University, Diepenbeek, Belgium
| | - Marcel Ameloot
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
| | - François Rineau
- Centre for Environmental Sciences, Environmental Biology, Hasselt University, Diepenbeek, Belgium
| | - Jan V. Colpaert
- Centre for Environmental Sciences, Environmental Biology, Hasselt University, Diepenbeek, Belgium
| | - Joske Ruytinx
- Centre for Environmental Sciences, Environmental Biology, Hasselt University, Diepenbeek, Belgium
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9
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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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10
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Childers DS, Avelar GM, Bain JM, Larcombe DE, Pradhan A, Budge S, Heaney H, Brown AJP. Impact of the Environment upon the Candida albicans Cell Wall and Resultant Effects upon Immune Surveillance. Curr Top Microbiol Immunol 2019; 425:297-330. [PMID: 31781866 DOI: 10.1007/82_2019_182] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The fungal cell wall is an essential organelle that maintains cellular morphology and protects the fungus from environmental insults. For fungal pathogens such as Candida albicans, it provides a degree of protection against attack by host immune defences. However, the cell wall also presents key epitopes that trigger host immunity and attractive targets for antifungal drugs. Rather than being a rigid shield, it has become clear that the fungal cell wall is an elastic organelle that permits rapid changes in cell volume and the transit of large liposomal particles such as extracellular vesicles. The fungal cell wall is also flexible in that it adapts to local environmental inputs, thereby enhancing the fitness of the fungus in these microenvironments. Recent evidence indicates that this cell wall adaptation affects host-fungus interactions by altering the exposure of major cell wall epitopes that are recognised by innate immune cells. Therefore, we discuss the impact of environmental adaptation upon fungal cell wall structure, and how this affects immune recognition, focussing on C. albicans and drawing parallels with other fungal pathogens.
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Affiliation(s)
- Delma S Childers
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Gabriela M Avelar
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Judith M Bain
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Daniel E Larcombe
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Arnab Pradhan
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK
| | - Susan Budge
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Helen Heaney
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK
| | - Alistair J P Brown
- Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, Foresterhill, Aberdeen, AB25 2ZD, UK.
- Medical Research Council Centre for Medical Mycology, University of Exeter, Geoffrey Pope Building, Stocker Road, Exeter, EX4 4QD, UK.
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11
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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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