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Guo Y, Guan T, Yu Q, Sanghai N, Shafiq K, Li M, Jiao X, Na D, Zhang G, Kong J. ALS-linked SOD1 mutations impair mitochondrial-derived vesicle formation and accelerate aging. Redox Biol 2024; 69:102972. [PMID: 38056310 PMCID: PMC10746562 DOI: 10.1016/j.redox.2023.102972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 11/06/2023] [Accepted: 11/20/2023] [Indexed: 12/08/2023] Open
Abstract
Oxidative stress (OS) is regarded as the dominant theory for aging. While compelling correlative data have been generated to support the OS theory, a direct cause-and-effect relationship between the accumulation of oxidation-mediated damage and aging has not been firmly established. Superoxide dismutase 1 (SOD1) is a primary antioxidant in all cells. It is, however, susceptible to oxidation due to OS and gains toxic properties to cells. This study investigates the role of oxidized SOD1 derived from amyotrophic lateral sclerosis (ALS) linked SOD1 mutations in cell senescence and aging. Herein, we have shown that the cell line NSC34 expressing the G93A mutation of human SOD1 (hSOD1G93A) entered premature senescence as evidenced by a decreased number of the 5-ethynyl-2'-deoxyuridine (EdU)-positive cells. There was an upregulation of cellular senescence markers compared to cells expressing the wild-type human SOD1 (hSOD1WT). Transgenic mice carrying the hSOD1G93A gene showed aging phenotypes at an early age (135 days) with high levels of P53 and P16 but low levels of SIRT1 and SIRT6 compared with age-matched hSOD1WT transgenic mice. Notably, the levels of oxidized SOD1 were significantly elevated in both the senescent NSC34 cells and 135-day hSOD1G93A mice. Selective removal of oxidized SOD1 by our CT4-directed autophagy significantly decelerated aging, indicating that oxidized SOD1 is a causal factor of aging. Intriguingly, mitochondria malfunctioned in both senescent NSC34 cells and middle-aged hSODG93A transgenic mice. They exhibited increased production of mitochondrial-derived vesicles (MDVs) in response to mild OS in mutant humanSOD1 (hSOD1) transgenic mice at a younger age; however, the mitochondrial response gradually declined with aging. In conclusion, our data show that oxidized SOD1 derived from ALS-linked SOD1 mutants is a causal factor for cellular senescence and aging. Compromised mitochondrial responsiveness to OS may serve as an indicator of premature aging.
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Affiliation(s)
- Ying Guo
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Canada; Department of Forensic Medicine, Hebei North University, Zhangjiakou, China
| | - Teng Guan
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Canada
| | - Qiang Yu
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Canada
| | - Nitesh Sanghai
- College of Pharmacy, Rady Faculty of Health Science, University of Manitoba, Canada
| | - Kashfia Shafiq
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Canada
| | - Meiyu Li
- Department of Forensic Medicine, Hebei North University, Zhangjiakou, China
| | - Xin Jiao
- Department of Forensic Medicine, Hebei North University, Zhangjiakou, China
| | - Donghui Na
- Department of Forensic Medicine, Hebei North University, Zhangjiakou, China
| | - Guohui Zhang
- Department of Forensic Medicine, Hebei North University, Zhangjiakou, China.
| | - Jiming Kong
- Department of Human Anatomy and Cell Science, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Canada.
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2
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Sharma R, Gibb AA, Barnts K, Elrod JW, Puri S. Alternative oxidase promotes high iron tolerance in Candida albicans. Microbiol Spectr 2023; 11:e0215723. [PMID: 37929974 PMCID: PMC10714975 DOI: 10.1128/spectrum.02157-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Accepted: 10/10/2023] [Indexed: 11/07/2023] Open
Abstract
IMPORTANCE The yeast C. albicans exhibits metabolic flexibility for adaptability to host niches with varying availability of nutrients including essential metals like iron. For example, blood is iron deplete, while the oral cavity and the intestinal lumen are considered iron replete. We show here that C. albicans can tolerate very high levels of environmental iron, despite an increase in high iron-induced reactive oxygen species (ROS) that it mitigates with the help of a unique oxidase, known as alternative oxidase (AOX). High iron induces AOX1/2 that limits mitochondrial accumulation of ROS. Genetic elimination of AOX1/2 resulted in diminished virulence during oropharyngeal candidiasis in high iron mice. Since human mitochondria lack AOX protein, it represents a unique target for treatment of fungal infections.
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Affiliation(s)
- Rishabh Sharma
- Oral Microbiome Research Laboratory, Kornberg School of Dentistry, Temple University, Philadelphia, Pennsylvania, USA
| | - Andrew A. Gibb
- Department of Cardiovascular Sciences, Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Kelcie Barnts
- Oral and Maxillofacial Pathology, Medicine and Surgery, Kornberg School of Dentistry, Temple University, Philadelphia, Pennsylvania, USA
| | - John W. Elrod
- Department of Cardiovascular Sciences, Cardiovascular Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, Pennsylvania, USA
| | - Sumant Puri
- Oral Microbiome Research Laboratory, Kornberg School of Dentistry, Temple University, Philadelphia, Pennsylvania, USA
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3
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Liu Z, Basso P, Hossain S, Liston SD, Robbins N, Whitesell L, Noble SM, Cowen LE. Multifactor transcriptional control of alternative oxidase induction integrates diverse environmental inputs to enable fungal virulence. Nat Commun 2023; 14:4528. [PMID: 37500616 PMCID: PMC10374912 DOI: 10.1038/s41467-023-40209-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 07/17/2023] [Indexed: 07/29/2023] Open
Abstract
Metabolic flexibility enables fungi to invade challenging host environments. In Candida albicans, a common cause of life-threatening infections in humans, an important contributor to flexibility is alternative oxidase (Aox) activity. Dramatic induction of this activity occurs under respiratory-stress conditions, which impair the classical electron transport chain (ETC). Here, we show that deletion of the inducible AOX2 gene cripples C. albicans virulence in mice by increasing immune recognition. To investigate further, we examined transcriptional regulation of AOX2 in molecular detail under host-relevant, ETC-inhibitory conditions. We found that multiple transcription factors, including Rtg1/Rtg3, Cwt1/Zcf11, and Zcf2, bind and regulate the AOX2 promoter, conferring thousand-fold levels of inducibility to AOX2 in response to distinct environmental stressors. Further dissection of this complex promoter revealed how integration of stimuli ranging from reactive species of oxygen, nitrogen, and sulfur to reduced copper availability is achieved at the transcriptional level to regulate AOX2 induction and enable pathogenesis.
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Affiliation(s)
- Zhongle Liu
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Pauline Basso
- UCSF Department of Microbiology & Immunology, San Francisco, CA, USA
| | - Saif Hossain
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Sean D Liston
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Nicole Robbins
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Luke Whitesell
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada
| | - Suzanne M Noble
- UCSF Department of Microbiology & Immunology, San Francisco, CA, USA.
- UCSF Department of Medicine, Division of Infectious Diseases, San Francisco, CA, USA.
| | - Leah E Cowen
- Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
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4
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Targeting the alternative oxidase (AOX) for human health and food security, a pharmaceutical and agrochemical target or a rescue mechanism? Biochem J 2022; 479:1337-1359. [PMID: 35748702 PMCID: PMC9246349 DOI: 10.1042/bcj20180192] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/23/2022] [Accepted: 06/07/2022] [Indexed: 11/25/2022]
Abstract
Some of the most threatening human diseases are due to a blockage of the mitochondrial electron transport chain (ETC). In a variety of plants, fungi, and prokaryotes, there is a naturally evolved mechanism for such threats to viability, namely a bypassing of the blocked portion of the ETC by alternative enzymes of the respiratory chain. One such enzyme is the alternative oxidase (AOX). When AOX is expressed, it enables its host to survive life-threatening conditions or, as in parasites, to evade host defenses. In vertebrates, this mechanism has been lost during evolution. However, we and others have shown that transfer of AOX into the genome of the fruit fly and mouse results in a catalytically engaged AOX. This implies that not only is the AOX a promising target for combating human or agricultural pathogens but also a novel approach to elucidate disease mechanisms or, in several cases, potentially a therapeutic cure for human diseases. In this review, we highlight the varying functions of AOX in their natural hosts and upon xenotopic expression, and discuss the resulting need to develop species-specific AOX inhibitors.
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5
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Interactions between copper homeostasis and the fungal cell wall affect copper stress resistance. PLoS Pathog 2022; 18:e1010195. [PMID: 35737716 PMCID: PMC9258870 DOI: 10.1371/journal.ppat.1010195] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 07/06/2022] [Accepted: 05/31/2022] [Indexed: 01/09/2023] Open
Abstract
Copper homeostasis mechanisms are essential for microbial adaption to changing copper levels within the host during infection. In the opportunistic fungal pathogen Cryptococcus neoformans (Cn), the Cn Cbi1/Bim1 protein is a newly identified copper binding and release protein that is highly induced during copper limitation. Recent studies demonstrated that Cbi1 functions in copper uptake through the Ctr1 copper transporter during copper limitation. However, the mechanism of Cbi1 action is unknown. The fungal cell wall is a dynamic structure primarily composed of carbohydrate polymers, such as chitin and chitosan, polymers known to strongly bind copper ions. We demonstrated that Cbi1 depletion affects cell wall integrity and architecture, connecting copper homeostasis with adaptive changes within the fungal cell wall. The cbi1Δ mutant strain possesses an aberrant cell wall gene transcriptional signature as well as defects in chitin / chitosan deposition and exposure. Furthermore, using Cn strains defective in chitosan biosynthesis, we demonstrated that cell wall chitosan modulates the ability of the fungal cell to withstand copper stress. Given the previously described role for Cbi1 in copper uptake, we propose that this copper-binding protein could be involved in shuttling copper from the cell wall to the copper transporter Ctr1 for regulated microbial copper uptake.
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6
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Ženíšková K, Grechnikova M, Sutak R. Copper Metabolism in Naegleria gruberi and Its Deadly Relative Naegleria fowleri. Front Cell Dev Biol 2022; 10:853463. [PMID: 35478954 PMCID: PMC9035749 DOI: 10.3389/fcell.2022.853463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 03/18/2022] [Indexed: 12/04/2022] Open
Abstract
Although copper is an essential nutrient crucial for many biological processes, an excessive concentration can be toxic and lead to cell death. The metabolism of this two-faced metal must be strictly regulated at the cell level. In this study, we investigated copper homeostasis in two related unicellular organisms: nonpathogenic Naegleria gruberi and the “brain-eating amoeba” Naegleria fowleri. We identified and confirmed the function of their specific copper transporters securing the main pathway of copper acquisition. Adjusting to different environments with varying copper levels during the life cycle of these organisms requires various metabolic adaptations. Using comparative proteomic analyses, measuring oxygen consumption, and enzymatic determination of NADH dehydrogenase, we showed that both amoebas respond to copper deprivation by upregulating the components of the branched electron transport chain: the alternative oxidase and alternative NADH dehydrogenase. Interestingly, analysis of iron acquisition indicated that this system is copper-dependent in N. gruberi but not in its pathogenic relative. Importantly, we identified a potential key protein of copper metabolism of N. gruberi, the homolog of human DJ-1 protein, which is known to be linked to Parkinson’s disease. Altogether, our study reveals the mechanisms underlying copper metabolism in the model amoeba N. gruberi and the fatal pathogen N. fowleri and highlights the differences between the two amoebas.
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7
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Fiołka MJ, Czaplewska P, Wójcik-Mieszawska S, Lewandowska A, Lewtak K, Sofińska-Chmiel W, Buchwald T. Metabolic, structural, and proteomic changes in Candida albicans cells induced by the protein-carbohydrate fraction of Dendrobaena veneta coelomic fluid. Sci Rep 2021; 11:16711. [PMID: 34408181 PMCID: PMC8373886 DOI: 10.1038/s41598-021-96093-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 08/02/2021] [Indexed: 01/14/2023] Open
Abstract
The isolated protein-polysaccharide fraction (AAF) from the coelomic fluid of Dendrobaena veneta earthworm shows effective activity against Candida albicans yeast. Fungal cells of the clinical strain after incubation with the active fraction were characterized by disturbed cell division and different morphological forms due to the inability to separate the cells from each other. Staining of the cells with acridine orange revealed a change in the pH of the AAF-treated cells. It was observed that, after the AAF treatment, the mitochondrial DNA migrated towards the nuclear DNA, whereupon both merged into a single nuclear structure, which preceded the apoptotic process. Cells with a large nucleus were imaged with the scanning electron cryomicroscopy (Cryo-SEM) technique, while enlarged mitochondria and the degeneration of cell structures were shown by transmission electron microscopy (TEM). The loss of the correct cell shape and cell wall integrity was visualized by both the TEM and SEM techniques. Mass spectrometry and relative quantitative SWATH MS analysis were used to determine the reaction of the C. albicans proteome to the components of the AAF fraction. AAF was observed to influence the expression of mitochondrial and oxidative stress proteins. The oxidative stress in C. albicans cells caused by the action of AAF was demonstrated by fluorescence microscopy, proteomic methods, and XPS spectroscopy. The secondary structure of AAF proteins was characterized by Raman spectroscopy. Analysis of the elemental composition of AAF confirmed the homogeneity of the preparation. The observed action of AAF, which targets not only the cell wall but also the mitochondria, makes the preparation a potential antifungal drug killing the cells of the C. albicans pathogen through apoptosis.
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Affiliation(s)
- Marta J Fiołka
- Department of Immunobiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland.
| | - Paulina Czaplewska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Sylwia Wójcik-Mieszawska
- Department of Immunobiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19, 20-033, Lublin, Poland
| | - Aleksandra Lewandowska
- Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Gdansk, Poland
| | - Kinga Lewtak
- Department of Cell Biology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Weronika Sofińska-Chmiel
- Analytical Laboratory, Institute of Chemical Sciences, Maria Curie-Skłodowska University, Lublin, Poland
| | - Tomasz Buchwald
- Faculty of Materials Science and Technical Physics, Institute of Materials Research and Quantum Engineering, Poznan University of Technology, Poznań, Poland
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8
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Hunsaker EW, Yu CHA, Franz KJ. Copper Availability Influences the Transcriptomic Response of Candida albicans to Fluconazole Stress. G3-GENES GENOMES GENETICS 2021; 11:6162163. [PMID: 33693623 PMCID: PMC8049437 DOI: 10.1093/g3journal/jkab065] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 02/23/2021] [Indexed: 01/16/2023]
Abstract
The ability of pathogens to maintain homeostatic levels of essential biometals is known to be important for survival and virulence in a host, which itself regulates metal availability as part of its response to infection. Given this importance of metal homeostasis, we sought to address how the availability of copper in particular impacts the response of the opportunistic fungal pathogen Candida albicans to treatment with the antifungal drug fluconazole. The present study reports whole transcriptome analysis via time-course RNA-seq of C. albicans cells exposed to fluconazole with and without 10 µM supplemental CuSO4 added to the growth medium. The results show widespread impacts of small changes in Cu availability on the transcriptional response of C. albicans to fluconazole. Of the 2359 genes that were differentially expressed under conditions of cotreatment, 50% were found to be driven uniquely by exposure to both Cu and fluconazole. The breadth of metabolic processes that were affected by cotreatment illuminates a fundamental intersectionality between Cu metabolism and fungal response to drug stress. More generally, these results show that seemingly minor fluctuations in Cu availability are sufficient to shift cells’ transcriptional response to drug stress. Ultimately, the findings may inform the development of new strategies that capitalize on drug-induced vulnerabilities in metal homeostasis pathways.
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Affiliation(s)
- Elizabeth W Hunsaker
- Department of Chemistry, French Family Science Center, Duke University, Durham, NC 27708, USA
| | | | - Katherine J Franz
- Department of Chemistry, French Family Science Center, Duke University, Durham, NC 27708, USA
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9
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Ceruloplasmin as a source of Cu for a fungal pathogen. J Inorg Biochem 2021; 219:111424. [PMID: 33765639 DOI: 10.1016/j.jinorgbio.2021.111424] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 02/28/2021] [Accepted: 03/08/2021] [Indexed: 12/22/2022]
Abstract
Copper is an essential metal for virtually all organisms, yet little is known about the extracellular sources of this micronutrient. In serum, the most abundant extracellular Cu-binding molecule is the multi‑copper oxidase ceruloplasmin (Cp). Cp levels increase during infection and inflammation, and pathogens can be exposed to high Cp at sites of infection. It is not known whether Cp might serve as a Cu source for microbial pathogens and we tested this using the opportunistic fungal pathogen Candida albicans. We find that C. albicans can use whole serum as a Cu source and that this Cu is sensed by the transcription factor protein Mac1. Mac1 activates expression of Mn-SOD3 superoxide dismutase and represses Cu/Zn-SOD1 during Cu starvation and both responses are regulated by serum Cu. We also show that purified human Cp can act as a sole source of Cu for the fungus and likewise modulates the Mac1 Cu stress response. To investigate whether Cp is a Cu source in serum, we compared the ability of C. albicans to use serum from wild type versus Cp-/- mutant mice. We find that serum lacking Cp is deficient in its ability to trigger the Mac1 Cu response. C. albicans did accumulate Cu from Cp-/- serum, but this Cu was not efficiently sensed by Mac1. We conclude that Cp and non-Cp Cu sources are not equivalent and are handled differently by the fungal cell. Overall, these studies are the first to show that Cp is a preferred source of Cu for a pathogen.
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10
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Smith AD, Garcia-Santamarina S, Ralle M, Loiselle DR, Haystead TA, Thiele DJ. Transcription factor-driven alternative localization of Cryptococcus neoformans superoxide dismutase. J Biol Chem 2021; 296:100391. [PMID: 33567338 PMCID: PMC7961099 DOI: 10.1016/j.jbc.2021.100391] [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: 11/24/2020] [Revised: 01/29/2021] [Accepted: 02/04/2021] [Indexed: 12/16/2022] Open
Abstract
Cryptococcus neoformans is an opportunistic fungal pathogen whose pathogenic lifestyle is linked to its ability to cope with fluctuating levels of copper (Cu), an essential metal involved in multiple virulence mechanisms, within distinct host niches. During lethal cryptococcal meningitis in the brain, C. neoformans senses a Cu-deficient environment and is highly dependent on its ability to scavenge trace levels of Cu from its host and adapt to Cu scarcity to successfully colonize this niche. In this study, we demonstrate for this critical adaptation, the Cu-sensing transcription factor Cuf1 differentially regulates the expression of the SOD1 and SOD2 superoxide dismutases in novel ways. Genetic and transcriptional analysis reveals Cuf1 specifies 5’-truncations of the SOD1 and SOD2 mRNAs through specific binding to Cu responsive elements within their respective promoter regions. This results in Cuf1-dependent repression of the highly abundant SOD1 and simultaneously induces expression of two isoforms of SOD2, the canonical mitochondrial targeted isoform and a novel alternative cytosolic isoform, from a single alternative transcript produced specifically under Cu limitation. The generation of cytosolic Sod2 during Cu limitation is required to maintain cellular antioxidant defense against superoxide stress both in vitro and in vivo. Further, decoupling Cuf1 regulation of Sod2 localization compromises the ability of C. neoformans to colonize organs in murine models of cryptococcosis. Our results provide a link between transcription factor–mediated alteration of protein localization and cell proliferation under stress, which could impact tissue colonization by a fungal pathogen.
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Affiliation(s)
- Aaron D Smith
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | | | - Martina Ralle
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, Oregon, USA
| | - David R Loiselle
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | - Timothy A Haystead
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA
| | - Dennis J Thiele
- Department of Pharmacology and Cancer Biology, Duke University, Durham, North Carolina, USA; Department of Biochemistry, Duke University, Durham, North Carolina, USA; Department of Molecular Genetics and Microbiology, Duke University, Durham, North Carolina, USA.
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11
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Culbertson EM, Culotta VC. Copper in infectious disease: Using both sides of the penny. Semin Cell Dev Biol 2021; 115:19-26. [PMID: 33423931 DOI: 10.1016/j.semcdb.2020.12.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 11/28/2020] [Accepted: 12/08/2020] [Indexed: 12/17/2022]
Abstract
The transition metal Cu is an essential micronutrient that serves as a co-factor for numerous enzymes involved in redox and oxygen chemistry. However, Cu is also a potentially toxic metal, especially to unicellular microbes that are in direct contact with their environment. Since 400 BCE, Cu toxicity has been leveraged for its antimicrobial properties and even today, Cu based materials are being explored as effective antimicrobials against human pathogens spanning bacteria, fungi, and viruses, including the SARS-CoV-2 agent of the 2019-2020 pandemic. Given that Cu has the double-edged property of being both highly toxic and an essential micronutrient, it plays an active and complicated role at the host-pathogen interface. Humans have evolved methods of incorporating Cu into innate and adaptive immune processes and both sides of the penny (Cu toxicity and Cu as a nutrient) are employed. Here we review the evolution of Cu in biology and its multi-faceted roles in infectious disease, from the viewpoints of the microbial pathogens as well as the animal hosts they infect.
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Affiliation(s)
- Edward M Culbertson
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA
| | - Valeria C Culotta
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD 21205, USA.
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12
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Culbertson EM, Bruno VM, Cormack BP, Culotta VC. Expanded role of the Cu-sensing transcription factor Mac1p in Candida albicans. Mol Microbiol 2020; 114:1006-1018. [PMID: 32808698 DOI: 10.1111/mmi.14591] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 08/13/2020] [Accepted: 08/13/2020] [Indexed: 12/11/2022]
Abstract
As part of the innate immune response, the host withholds metal micronutrients such as Cu from invading pathogens, and microbes respond through metal starvation stress responses. With the opportunistic fungal pathogen Candida albicans, the Cu-sensing transcription factor Mac1p governs the cellular response to Cu starvation by controlling Cu import. Mac1p additionally controls reactive oxygen species (ROS) homeostasis by repressing a Cu-containing superoxide dismutase (SOD1) and inducing Mn-containing SOD3 as a non-Cu alternative. We show here that C. albicans Mac1p is essential for virulence in a mouse model for disseminated candidiasis and that the cellular functions of Mac1p extend beyond Cu uptake and ROS homeostasis. Specifically, mac1∆/∆ mutants are profoundly deficient in mitochondrial respiration and Fe accumulation, both Cu-dependent processes. Surprisingly, these deficiencies are not simply the product of impaired Cu uptake; rather mac1∆/∆ mutants appear defective in Cu allocation. The respiratory defect of mac1∆/∆ mutants was greatly improved by a sod1∆/∆ mutation, demonstrating a role for SOD1 repression by Mac1p in preserving respiration. Mac1p downregulates the major Cu consumer SOD1 to spare Cu for respiration that is essential for virulence of this fungal pathogen. The implications for such Cu homeostasis control in other pathogenic fungi are discussed.
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Affiliation(s)
- Edward M Culbertson
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Vincent M Bruno
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Brendan P Cormack
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Valeria C Culotta
- The Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
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13
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From economy to luxury: Copper homeostasis in Chlamydomonas and other algae. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2020; 1867:118822. [PMID: 32800924 DOI: 10.1016/j.bbamcr.2020.118822] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/03/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022]
Abstract
Plastocyanin and cytochrome c6, abundant proteins in photosynthesis, are readouts for cellular copper status in Chlamydomonas and other algae. Their accumulation is controlled by a transcription factor copper response regulator (CRR1). The replacement of copper-containing plastocyanin with heme-containing cytochrome c6 spares copper and permits preferential copper (re)-allocation to cytochrome oxidase. Under copper-replete situations, the quota depends on abundance of various cuproproteins and is tightly regulated, except under zinc-deficiency where acidocalcisomes over-accumulate Cu(I). CRR1 has a transcriptional activation domain, a Zn-dependent DNA binding SBP-domain with a nuclear localization signal, and a C-terminal Cys-rich region that represses the zinc regulon. CRR1 activates >60 genes in Chlamydomonas through GTAC-containing CuREs; transcriptome differences are recapitulated in the proteome. The differentially-expressed genes encode assimilatory copper transporters of the CTR/SLC31 family including a novel soluble molecule, redox enzymes in the tetrapyrrole pathway that promote chlorophyll biosynthesis and photosystem 1 accumulation, and other oxygen-dependent enzymes, which may influence thylakoid membrane lipids, specifically polyunsaturated galactolipids and γ-tocopherol. CRR1 also down-regulates 2 proteins in Chlamydomonas: for plastocyanin, by activation of proteolysis, while for the di‑iron subunit of the cyclase in chlorophyll biosynthesis, through activation of an upstream promoter that generates a poorly-translated 5' extended transcript containing multiple short ORFs that inhibit translation. The functions of many CRR1-target genes are unknown, and the copper protein inventory in Chlamydomonas includes several whose functions are unexplored. The comprehensive picture of cuproproteins and copper homeostasis in this system is well-suited for reverse genetic analyses of these under-investigated components in copper biology.
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14
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Petito G, de Curcio JS, Pereira M, Bailão AM, Paccez JD, Tristão GB, de Morais COB, de Souza MV, de Castro Moreira Santos A, Fontes W, Ricart CAO, de Almeida Soares CM. Metabolic Adaptation of Paracoccidioides brasiliensis in Response to in vitro Copper Deprivation. Front Microbiol 2020; 11:1834. [PMID: 32849434 PMCID: PMC7430155 DOI: 10.3389/fmicb.2020.01834] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Accepted: 07/13/2020] [Indexed: 02/06/2023] Open
Abstract
Copper is an essential micronutrient for the performance of important biochemical processes such as respiration detoxification, and uptake of metals like iron. Studies have shown that copper deprivation is a strategy used by the host against pathogenic fungi such as Cryptoccocus neoformans and Candida albicans during growth and development of infections in the lungs and kidneys. Although there are some studies, little is known about the impact of copper deprivation in members of the Paracoccidioides genus. Therefore, using isobaric tag labeling (iTRAQ)-Based proteomic approach and LC-MS/MS, we analyzed the impact of in vitro copper deprivation in the metabolism of Paracoccidioides brasiliensis. One hundred and sixty-four (164) differentially abundant proteins were identified when yeast cells were deprived of copper, which affected cellular respiration and detoxification processes. Changes in cellular metabolism such as increased beta oxidation and cell wall remodeling were described.
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Affiliation(s)
- Guilherme Petito
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
- Programa de Pós-graduação em Genética e Biologia Molecular, Universidade Federal de Goiás, Goiânia, Brazil
| | - Juliana Santana de Curcio
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Maristela Pereira
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Alexandre Melo Bailão
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Juliano Domiraci Paccez
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | - Gabriel Brum Tristão
- Laboratório de Biologia Molecular, Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Brazil
| | | | - Marcelo Valle de Souza
- Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, Brasília, Brazil
| | | | - Wagner Fontes
- Departamento de Biologia Celular, Instituto de Biologia, Universidade de Brasília, Brasília, Brazil
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15
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Hunsaker EW, Franz KJ. Candida albicans reprioritizes metal handling during fluconazole stress. Metallomics 2020; 11:2020-2032. [PMID: 31709426 DOI: 10.1039/c9mt00228f] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Maintenance of metal homeostasis is critical to cell survival due to the multitude of cellular processes that depend on one or more metal cofactors. Here, we show that the opportunistic fungal pathogen Candida albicans extensively remodels its metal homeostasis networks to respond to treatment with the antifungal drug fluconazole. Disruption of the ergosterol biosynthetic pathway by fluconazole requires C. albicans adaptation, including increased Cu import and storage, increased retention of Fe, Mn, and Zn, altered utilization of Cu- and Mn-dependent enzymes, mobilization of Fe stores, and increased production of the heme prosthetic group utilized by the enzyme target of fluconazole. The findings offer a new perspective for thinking about fungal response to drug stress that pushes cells out of their metal homeostatic zones, leading them to enact metal-associated adaptation mechanisms to restore homeostasis to survive.
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Affiliation(s)
- Elizabeth W Hunsaker
- Department of Chemistry, Duke University, French Family Science Center, 124 Science Drive, Durham, North Carolina 27708, USA.
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16
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Dawson CS, Garcia-Ceron D, Rajapaksha H, Faou P, Bleackley MR, Anderson MA. Protein markers for Candida albicans EVs include claudin-like Sur7 family proteins. J Extracell Vesicles 2020; 9:1750810. [PMID: 32363014 PMCID: PMC7178836 DOI: 10.1080/20013078.2020.1750810] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 03/24/2020] [Accepted: 03/27/2020] [Indexed: 01/09/2023] Open
Abstract
Background: Fungal extracellular vesicles (EVs) have been implicated in host-pathogen and pathogen-pathogen communication in some fungal diseases. In depth research into fungal EVs has been hindered by the lack of specific protein markers such as those found in mammalian EVs that have enabled sophisticated isolation and analysis techniques. Despite their role in fungal EV biogenesis, ESCRT proteins such as Vps23 (Tsg101) and Bro1 (ALIX) are not present as fungal EV cargo. Furthermore, tetraspanin homologs are yet to be identified in many fungi including the model yeast S. cerevisiae. Objective: We performed de novo identification of EV protein markers for the major human fungal pathogen Candida albicans with adherence to MISEV2018 guidelines. Materials and methods: EVs were isolated by differential ultracentrifugation from DAY286, ATCC90028 and ATCC10231 yeast cells, as well as DAY286 biofilms. Whole cell lysates (WCL) were also obtained from the EV-releasing cells. Label-free quantitative proteomics was performed to determine the set of proteins consistently enriched in EVs compared to WCL. Results: 47 proteins were consistently enriched in C. albicans EVs. We refined these to 22 putative C. albicans EV protein markers including the claudin-like Sur7 family (Pfam: PF06687) proteins Sur7 and Evp1 (orf19.6741). A complementary set of 62 EV depleted proteins was selected as potential negative markers. Conclusions: The marker proteins for C. albicans EVs identified in this study will be useful tools for studies on EV biogenesis and cargo loading in C. albicans and potentially other fungal species and will also assist in elucidating the role of EVs in C. albicans pathogenesis. Many of the proteins identified as putative markers are fungal specific proteins indicating that the pathways of EV biogenesis and cargo loading may be specific to fungi, and that assumptions made based on studies in mammalian cells could be misleading. Abbreviations: A1 – ATCC10231; A9 – ATCC90028; DAY B – DAY286 biofilm; DAY Y – DAY286 yeast; EV – extracellular vesicle; Evp1 – extracellular vesicle protein 1 (orf19.6741); GO – gene ontology; Log2(FC) – log2(fold change); MCC – membrane compartment of Can1; MDS – multidimensional scaling; MISEV – minimal information for studies of EVs; sEVs – small EVs; SP – signal peptide; TEMs – tetraspanin enriched microdomains; TM – transmembrane; VDM – vesicle-depleted medium; WCL – whole cell lysate
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Affiliation(s)
- Charlotte S Dawson
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science. La Trobe University, Australia.,Department of Biochemistry, Cambridge Centre for Proteomics, Milner Therapeutics Institute, Jeffrey Cheah Biomedical Centre, University of Cambridge, Cambridge, UK
| | - Donovan Garcia-Ceron
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science. La Trobe University, Australia
| | - Harinda Rajapaksha
- La Trobe Comprehensive Proteomics Platform, La Trobe Institute for Molecular Science. La Trobe University, Australia
| | - Pierre Faou
- La Trobe Comprehensive Proteomics Platform, La Trobe Institute for Molecular Science. La Trobe University, Australia
| | - Mark R Bleackley
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science. La Trobe University, Australia
| | - Marilyn A Anderson
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science. La Trobe University, Australia
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17
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The antimicrobial and cytotoxic effects of a copper-loaded zinc oxide phosphate cement. Clin Oral Investig 2020; 24:3899-3909. [PMID: 32198658 PMCID: PMC7544705 DOI: 10.1007/s00784-020-03257-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 03/06/2020] [Indexed: 01/25/2023]
Abstract
Objectives Evidence about modifications of dental luting materials to minimize biological failure at the “marginal gap” between teeth and fixed prosthodontics is scarce. We compared a copper-modified (Co-ZOP) and a conventional zinc oxide phosphate cement (ZOP) in terms of antimicrobial and cytotoxic potentials in vitro and in vivo. Materials and methods Specimens of ZOP and Co-ZOP were characterized by the mean arithmetic roughness (Ra) and surface free energy (SFE). Powder components were examined using scanning electron microscopy (SEM). Energy-dispersive X-ray spectroscopy (EDX) showed elemental material compositions. In vitro microbial adhesion was shown using SEM, luminescence, and fluorescence assays. CCK-8 assays of mouse fibroblasts (L929) and human gingival fibroblasts (GF-1) were performed after 6, 24, and 48 h of specimen incubation. In vivo, ZOP and Co-ZOP specimens were applied intraorally for 12 h; biofilm accumulation was shown using SEM. Results Ra of ZOP and Co-ZOP showed no significant differences; SFE was significantly higher for Co-ZOP. EDX exhibited minor copper radiation for Co-ZOP, none for ZOP. In vitro fungal adhesion to Co-ZOP was significantly higher than to ZOP; in vitro streptococcal adhesion, cytotoxicity, and in vivo biofilm formation were not significantly different. Conclusions Co-ZOP showed low surface allocations of copper with no improved antimicrobial properties compared with conventional ZOP in vitro or in vivo. Clinical relevance Antimicrobial effects and low cytotoxicity of biomaterials are important for the clinical outcome. Based on our in vitro and in vivo results, no clinical recommendation can be given for the tested Co-ZOP.
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18
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Schatzman SS, Peterson RL, Teka M, He B, Cabelli DE, Cormack BP, Culotta VC. Copper-only superoxide dismutase enzymes and iron starvation stress in Candida fungal pathogens. J Biol Chem 2019; 295:570-583. [PMID: 31806705 DOI: 10.1074/jbc.ra119.011084] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 11/27/2019] [Indexed: 12/11/2022] Open
Abstract
Copper (Cu)-only superoxide dismutases (SOD) represent a newly characterized class of extracellular SODs important for virulence of several fungal pathogens. Previous studies of the Cu-only enzyme SOD5 from the opportunistic fungal pathogen Candida albicans have revealed that the active-site structure and Cu binding of SOD5 strongly deviate from those of Cu/Zn-SODs in its animal hosts, making Cu-only SODs a possible target for future antifungal drug design. C. albicans also expresses a Cu-only SOD4 that is highly similar in sequence to SOD5, but is poorly characterized. Here, we compared the biochemical, biophysical, and cell biological properties of C. albicans SOD4 and SOD5. Analyzing the recombinant proteins, we found that, similar to SOD5, Cu-only SOD4 can react with superoxide at rates approaching diffusion limits. Both SODs were monomeric and they exhibited similar binding affinities for their Cu cofactor. In C. albicans cultures, SOD4 and SOD5 were predominantly cell wall proteins. Despite these similarities, the SOD4 and SOD5 genes strongly differed in transcriptional regulation. SOD5 was predominantly induced during hyphal morphogenesis, together with a fungal burst in reactive oxygen species. Conversely, SOD4 expression was specifically up-regulated by iron (Fe) starvation and controlled by the Fe-responsive transcription factor SEF1. Interestingly, Candida tropicalis and the emerging fungal pathogen Candida auris contain a single SOD5-like SOD rather than a pair, and in both fungi, this SOD was induced by Fe starvation. This unexpected link between Fe homeostasis and extracellular Cu-SODs may help many fungi adapt to Fe-limited conditions of their hosts.
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Affiliation(s)
- Sabrina S Schatzman
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Ryan L Peterson
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Mieraf Teka
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Bixi He
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205
| | - Diane E Cabelli
- Chemistry Department, Brookhaven National Laboratories, Upton, New York 11973
| | - Brendan P Cormack
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Valeria C Culotta
- Department of Biochemistry and Molecular Biology, The Johns Hopkins University Bloomberg School of Public Health, Baltimore, Maryland 21205.
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19
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Folgueira I, Lamas J, de Felipe AP, Sueiro RA, Leiro JM. Identification and Molecular Characterization of Superoxide Dismutases Isolated From A Scuticociliate Parasite: Physiological Role in Oxidative Stress. Sci Rep 2019; 9:13329. [PMID: 31527617 PMCID: PMC6746850 DOI: 10.1038/s41598-019-49750-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 08/22/2019] [Indexed: 12/20/2022] Open
Abstract
Philasterides dicentrarchi is a free-living microaerophilic scuticociliate that can become a facultative parasite and cause a serious parasitic disease in farmed fish. Both the free-living and parasitic forms of this scuticociliate are exposed to oxidative stress associated with environmental factors and the host immune system. The reactive oxygen species (ROS) generated by the host are neutralized by the ciliate by means of antioxidant defences. In this study we aimed to identify metalloenzymes with superoxide dismutase (SOD) activity capable of inactivating the superoxide anion (•O2-) generated during induction of oxidative stress. P. dicentrarchi possesses the three characteristic types of SOD isoenzymes in eukaryotes: copper/zinc-SOD, manganese-SOD and iron-SOD. The Cu/Zn-SOD isoenzymes comprise three types of homodimeric proteins (CSD1-3) of molecular weight (MW) 34-44 kDa and with very different AA sequences. All Cu/Zn-SODs are sensitive to NaCN, located in the cytosol and in the alveolar sacs, and one of them (CSD2) is extracellular. Mn- and Fe-SOD transcripts encode homodimeric proteins (MSD and FSD, respectively) in their native state: a) MSD (MW 50 kDa) is insensitive to H2O2 and NaN3 and is located in the mitochondria; and b) FSD (MW 60 kDa) is sensitive to H2O2, NaN3 and the polyphenol trans-resveratrol and is located extracellularly. Expression of SOD isoenzymes increases when •O2- is induced by ultraviolet (UV) irradiation, and the increase is proportional to the dose of energy applied, indicating that these enzymes are actively involved in cellular protection against oxidative stress.
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Affiliation(s)
- Iria Folgueira
- Department of Microbiology and Parasitology, Laboratory of Parasitology, Institute of Research and Food Analysis, Campus Vida, University of Santiago de Compostela, E-15782, Santiago de Compostela, Spain
| | - Jesús Lamas
- Department of Fundamental Biology, Institute of Aquaculture, Campus Vida, University of Santiago de Compostela, E-15782, Santiago de Compostela, Spain
| | - Ana Paula de Felipe
- Department of Microbiology and Parasitology, Laboratory of Parasitology, Institute of Research and Food Analysis, Campus Vida, University of Santiago de Compostela, E-15782, Santiago de Compostela, Spain
| | - Rosa Ana Sueiro
- Department of Microbiology and Parasitology, Laboratory of Parasitology, Institute of Research and Food Analysis, Campus Vida, University of Santiago de Compostela, E-15782, Santiago de Compostela, Spain
| | - José Manuel Leiro
- Department of Fundamental Biology, Institute of Aquaculture, Campus Vida, University of Santiago de Compostela, E-15782, Santiago de Compostela, Spain.
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20
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Hunsaker EW, Franz KJ. Copper potentiates azole antifungal activity in a way that does not involve complex formation. Dalton Trans 2019; 48:9654-9662. [PMID: 30888372 PMCID: PMC6613581 DOI: 10.1039/c9dt00642g] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
To survive, fungal pathogens must acquire nutrient metals that are restricted by the host while also tolerating mechanisms of metal toxicity that are induced by the host. Given this dual vulnerability, we hypothesized that a pathogen's access to and control of essential yet potentially dangerous metal ions would affect fungal tolerance to antifungal drug stress. Here, we show that Candida albicans becomes sensitized to both Cu limitation and Cu elevation during exposure in liquid culture to the antifungal drug fluconazole, a widely prescribed antifungal agent. Spectroscopic data confirm that while fluconazole forms a complex with Cu(ii) in water, interactions of fluconazole with neither Cu(ii) nor Cu(i) are observed in the cell culture media used for the cellular assays. This result is further supported by growth assays in deletion strains that lack Cu import machinery. Overall, we establish that increases in Cu levels by as little as 40 nM over basal levels in the growth medium reduce tolerance of C. albicans to fluconazole in a way that does not require formation of a Cu-fluconazole complex. Rather, our data point to a more complex relationship between drug stress and Cu availability that gives rise to metal-mediated outcomes of drug treatment.
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Affiliation(s)
- Elizabeth W Hunsaker
- Department of Chemistry, Duke University, French Family Science Center, 124 Science Drive, 27708, Durham, NC, USA.
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21
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Hypoxia Promotes Immune Evasion by Triggering β-Glucan Masking on the Candida albicans Cell Surface via Mitochondrial and cAMP-Protein Kinase A Signaling. mBio 2018; 9:mBio.01318-18. [PMID: 30401773 PMCID: PMC6222127 DOI: 10.1128/mbio.01318-18] [Citation(s) in RCA: 80] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Organisms must adapt to changes in oxygen tension if they are to exploit the energetic benefits of reducing oxygen while minimizing the potentially damaging effects of oxidation. Consequently, organisms in all eukaryotic kingdoms display robust adaptation to hypoxia (low oxygen levels). This is particularly important for fungal pathogens that colonize hypoxic niches in the host. We show that adaptation to hypoxia in the major fungal pathogen of humans Candida albicans includes changes in cell wall structure and reduced exposure, at the cell surface, of β-glucan, a key pathogen-associated molecular pattern (PAMP). This leads to reduced phagocytosis by murine bone marrow-derived macrophages and decreased production of IL-10, RANTES, and TNF-α by peripheral blood mononuclear cells, suggesting that hypoxia-induced β-glucan masking has a significant effect upon C. albicans-host interactions. We show that hypoxia-induced β-glucan masking is dependent upon both mitochondrial and cAMP-protein kinase A (PKA) signaling. The decrease in β-glucan exposure is blocked by mutations that affect mitochondrial functionality (goa1Δ and upc2Δ) or that decrease production of hydrogen peroxide in the inner membrane space (sod1Δ). Furthermore, β-glucan masking is enhanced by mutations that elevate mitochondrial reactive oxygen species (aox1Δ). The β-glucan masking defects displayed by goa1Δ and upc2Δ cells are suppressed by exogenous dibutyryl-cAMP. Also, mutations that inactivate cAMP synthesis (cyr1Δ) or PKA (tpk1Δ tpk2Δ) block the masking phenotype. Our data suggest that C. albicans responds to hypoxic niches by inducing β-glucan masking via a mitochondrial cAMP-PKA signaling pathway, thereby modulating local immune responses and promoting fungal colonization.IMPORTANCE Animal, plant, and fungal cells occupy environments that impose changes in oxygen tension. Consequently, many species have evolved mechanisms that permit robust adaptation to these changes. The fungal pathogen Candida albicans can colonize hypoxic (low oxygen) niches in its human host, such as the lower gastrointestinal tract and inflamed tissues, but to colonize its host, the fungus must also evade local immune defenses. We reveal, for the first time, a defined link between hypoxic adaptation and immune evasion in C. albicans As this pathogen adapts to hypoxia, it undergoes changes in cell wall structure that include masking of β-glucan at its cell surface, and it becomes better able to evade phagocytosis by innate immune cells. We also define the signaling mechanisms that mediate hypoxia-induced β-glucan masking, showing that they are dependent on mitochondrial signaling and the cAMP-protein kinase pathway. Therefore, hypoxia appears to trigger immune evasion in this fungal pathogen.
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22
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Schatzman SS, Culotta VC. Chemical Warfare at the Microorganismal Level: A Closer Look at the Superoxide Dismutase Enzymes of Pathogens. ACS Infect Dis 2018. [PMID: 29517910 DOI: 10.1021/acsinfecdis.8b00026] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Superoxide anion radical is generated as a natural byproduct of aerobic metabolism but is also produced as part of the oxidative burst of the innate immune response design to kill pathogens. In living systems, superoxide is largely managed through superoxide dismutases (SODs), families of metalloenzymes that use Fe, Mn, Ni, or Cu cofactors to catalyze the disproportionation of superoxide to oxygen and hydrogen peroxide. Given the bursts of superoxide faced by microbial pathogens, it comes as no surprise that SOD enzymes play important roles in microbial survival and virulence. Interestingly, microbial SOD enzymes not only detoxify host superoxide but also may participate in signaling pathways that involve reactive oxygen species derived from the microbe itself, particularly in the case of eukaryotic pathogens. In this Review, we will discuss the chemistry of superoxide radicals and the role of diverse SOD metalloenzymes in bacterial, fungal, and protozoan pathogens. We will highlight the unique features of microbial SOD enzymes that have evolved to accommodate the harsh lifestyle at the host-pathogen interface. Lastly, we will discuss key non-SOD superoxide scavengers that specific pathogens employ for defense against host superoxide.
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Affiliation(s)
- Sabrina S. Schatzman
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Pubic Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, Maryland 21205, United States
| | - Valeria C. Culotta
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Pubic Health, Johns Hopkins University, 615 N. Wolfe Street, Baltimore, Maryland 21205, United States
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23
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Garcia-Santamarina S, Festa RA, Smith AD, Yu CH, Probst C, Ding C, Homer CM, Yin J, Noonan JP, Madhani H, Perfect JR, Thiele DJ. Genome-wide analysis of the regulation of Cu metabolism in Cryptococcus neoformans. Mol Microbiol 2018; 108:473-494. [PMID: 29608794 PMCID: PMC5980777 DOI: 10.1111/mmi.13960] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2018] [Indexed: 12/13/2022]
Abstract
The ability of the human fungal pathogen Cryptococcus neoformans to adapt to variable copper (Cu) environments within the host is key for successful dissemination and colonization. During pulmonary infection, host alveolar macrophages compartmentalize Cu into the phagosome and C. neoformans Cu-detoxifying metallothioneins, MT1 and MT2, are required for survival of the pathogen. In contrast, during brain colonization the C. neoformans Cu+ importers Ctr1 and Ctr4 are required for virulence. Central for the regulation and expression of both the Cu detoxifying MT1/2 and the Cu acquisition Ctr1/4 proteins is the Cu-metalloregulatory transcription factor Cuf1, an established C. neoformans virulence factor. Due to the importance of the distinct C. neoformans Cu homeostasis mechanisms during host colonization and virulence, and to the central role of Cuf1 in regulating Cu homeostasis, we performed a combination of RNA-Seq and ChIP-Seq experiments to identify differentially transcribed genes between conditions of high and low Cu. We demonstrate that the transcriptional regulation exerted by Cuf1 is intrinsically complex and that Cuf1 also functions as a transcriptional repressor. The Cu- and Cuf1-dependent regulon in C. neoformans reveals new adaptive mechanisms for Cu homeostasis in this pathogenic fungus and identifies potential new pathogen-specific targets for therapeutic intervention in fungal infections.
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Affiliation(s)
- Sarela Garcia-Santamarina
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Richard A. Festa
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Aaron D. Smith
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Chen-Hsin Yu
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Corinna Probst
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Chen Ding
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Christina M. Homer
- Department of Biochemistry and Biophysics, UCSF, San Francisco, California, USA
| | - Jun Yin
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - James P. Noonan
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Hiten Madhani
- Department of Biochemistry and Biophysics, UCSF, San Francisco, California, USA
| | - John R. Perfect
- Division of Infectious Diseases, Department of Medicine, Duke University School of Medicine, Durham, North Carolina, USA
| | - Dennis J. Thiele
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Molecular Genetics and Microbiology, Duke University School of Medicine, Durham, North Carolina, USA
- Department of Biochemistry, Duke University School of Medicine, Durham, North Carolina, USA
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24
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Abstract
The balance between reactive oxygen species and reactive nitrogen species production by the host and stress response by fungi is a key axis of the host-pathogen interaction. This review will describe emerging themes in fungal pathogenesis underpinning this axis.
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Affiliation(s)
- Adilia Warris
- Medical Research Centre for Medical Mycology, Aberdeen Fungal Group, Institute of Medical Sciences, University of Aberdeen, UK
| | - Elizabeth R Ballou
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
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25
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Wiemann P, Perevitsky A, Lim FY, Shadkchan Y, Knox BP, Landero Figueora JA, Choera T, Niu M, Steinberger AJ, Wüthrich M, Idol RA, Klein BS, Dinauer MC, Huttenlocher A, Osherov N, Keller NP. Aspergillus fumigatus Copper Export Machinery and Reactive Oxygen Intermediate Defense Counter Host Copper-Mediated Oxidative Antimicrobial Offense. Cell Rep 2018; 19:1008-1021. [PMID: 28467895 DOI: 10.1016/j.celrep.2017.04.019] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 03/13/2017] [Accepted: 04/06/2017] [Indexed: 12/23/2022] Open
Abstract
The Fenton-chemistry-generating properties of copper ions are considered a potent phagolysosome defense against pathogenic microbes, yet our understanding of underlying host/microbe dynamics remains unclear. We address this issue in invasive aspergillosis and demonstrate that host and fungal responses inextricably connect copper and reactive oxygen intermediate (ROI) mechanisms. Loss of the copper-binding transcription factor AceA yields an Aspergillus fumigatus strain displaying increased sensitivity to copper and ROI in vitro, increased intracellular copper concentrations, decreased survival in challenge with murine alveolar macrophages (AMΦs), and reduced virulence in a non-neutropenic murine model. ΔaceA survival is remediated by dampening of host ROI (chemically or genetically) or enhancement of copper-exporting activity (CrpA) in A. fumigatus. Our study exposes a complex host/microbe multifactorial interplay that highlights the importance of host immune status and reveals key targetable A. fumigatus counter-defenses.
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Affiliation(s)
- Philipp Wiemann
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
| | - Adi Perevitsky
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Fang Yun Lim
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
| | - Yana Shadkchan
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Benjamin P Knox
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
| | - Julio A Landero Figueora
- University of Cincinnati/Agilent Technologies Metallomics Center of the Americas, Department of Chemistry, University of Cincinnati, Cincinnati, OH 45221, USA
| | - Tsokyi Choera
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
| | - Mengyao Niu
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA
| | | | - Marcel Wüthrich
- Department of Pediatrics, University of Wisconsin, Madison, WI 53706, USA
| | - Rachel A Idol
- Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Bruce S Klein
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA; Department of Pediatrics, University of Wisconsin, Madison, WI 53706, USA; Department of Medicine, University of Wisconsin, Madison, WI 53706, USA
| | - Mary C Dinauer
- Department of Pediatrics, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA; Department of Pathology and Immunology, Washington University School of Medicine in St. Louis, St. Louis, MO 63110, USA
| | - Anna Huttenlocher
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA; Department of Pediatrics, University of Wisconsin, Madison, WI 53706, USA
| | - Nir Osherov
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Nancy P Keller
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, WI 53706, USA; Department of Bacteriology, University of Wisconsin, Madison, WI 53706, USA.
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Role of Calprotectin in Withholding Zinc and Copper from Candida albicans. Infect Immun 2018; 86:IAI.00779-17. [PMID: 29133349 DOI: 10.1128/iai.00779-17] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 12/16/2022] Open
Abstract
The opportunistic fungal pathogen Candida albicans acquires essential metals from the host, yet the host can sequester these micronutrients through a process known as nutritional immunity. How the host withholds metals from C. albicans has been poorly understood; here we examine the role of calprotectin (CP), a transition metal binding protein. When CP depletes bioavailable Zn from the extracellular environment, C. albicans strongly upregulates ZRT1 and PRA1 for Zn import and maintains constant intracellular Zn through numerous cell divisions. We show for the first time that CP can also sequester Cu by binding Cu(II) with subpicomolar affinity. CP blocks fungal acquisition of Cu from serum and induces a Cu starvation stress response involving SOD1 and SOD3 superoxide dismutases. These transcriptional changes are mirrored when C. albicans invades kidneys in a mouse model of disseminated candidiasis, although the responses to Cu and Zn limitations are temporally distinct. The Cu response progresses throughout 72 h, while the Zn response is short-lived. Notably, these stress responses were attenuated in CP null mice, but only at initial stages of infection. Thus, Zn and Cu pools are dynamic at the host-pathogen interface and CP acts early in infection to restrict metal nutrients from C. albicans.
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Broxton CN, He B, Bruno VM, Culotta VC. A role for Candida albicans superoxide dismutase enzymes in glucose signaling. Biochem Biophys Res Commun 2017; 495:814-820. [PMID: 29154829 DOI: 10.1016/j.bbrc.2017.11.084] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Accepted: 11/12/2017] [Indexed: 01/18/2023]
Abstract
The Saccharomyces cerevisiae and Candida albicans yeasts have evolved to differentially use glucose for fermentation versus respiration. S. cerevisiae is Crabtree positive, where glucose represses respiration and promotes fermentation, while the opportunistic fungal pathogen C. albicans is Crabtree negative and does not repress respiration with glucose. We have previously shown that glucose control in S. cerevisiae involves the antioxidant enzyme Cu/Zn superoxide dismutase (SOD1), where H2O2 generated by SOD1 stabilizes the casein kinase YCK1 for glucose sensing. We now demonstrate that C. albicans SODs also participate in glucose regulation. C. albicans expresses two cytosolic SODs, Cu/Zn SOD1 and Mn containing SOD3, and both complemented a S. cerevisiae sod1Δ mutant in stabilizing YCK1. Moreover, in C. albicans cells, both SODs functioned to repress glucose transporter genes in response to glucose. However, the action of SODs in glucose control has diverged in the two yeasts. In S. cerevisiae, SOD1 specifically functions in the glucose sensing pathway involving YCK1 and the RGT1 repressor, but the analogous YCK/RGT1 pathway in C. albicans shows no control by SOD enzymes. Instead C. albicans SODs work in the glucose repression pathway involving the MIG1 transcriptional repressor. In C. albicans, the SODs repress glucose uptake, while in S. cerevisiae, SOD1 activates glucose uptake, in accordance with the divergent modes for glucose utilization in these two distantly related yeasts.
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Affiliation(s)
- Chynna N Broxton
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Bixi He
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA
| | - Vincent M Bruno
- Department Microbiology and Immunology, Institute for Genome Sciences, University of Maryland School of Medicine, 801 W. Baltimore St, Baltimore, MD 21201, USA
| | - Valeria C Culotta
- Department of Biochemistry and Molecular Biology, Johns Hopkins University Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, MD 21205, USA.
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Urrialde V, Alburquerque B, Guirao-Abad JP, Pla J, Argüelles JC, Alonso-Monge R. Arsenic inorganic compounds cause oxidative stress mediated by the transcription factor PHO4 in Candida albicans. Microbiol Res 2017; 203:10-18. [DOI: 10.1016/j.micres.2017.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 05/08/2017] [Accepted: 06/14/2017] [Indexed: 10/19/2022]
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