1
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Ganz T, Nemeth E. Hypoferremia of inflammation: Innate host defense against infections. Blood Cells Mol Dis 2024; 104:102777. [PMID: 37391347 DOI: 10.1016/j.bcmd.2023.102777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/18/2023] [Accepted: 06/19/2023] [Indexed: 07/02/2023]
Abstract
Iron is an essential nutrient for microbes, plants and animals. Multicellular organisms have evolved multiple strategies to control invading microbes by restricting microbial access to iron. Hypoferremia of inflammation is a rapidly-acting organismal response that prevents the formation of iron species that would be readily accessible to microbes. This review takes an evolutionary perspective to explore the mechanisms and host defense function of hypoferremia of inflammation and its clinical implications.
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Affiliation(s)
- Tomas Ganz
- Department of Medicine, David Geffen School of Medicine at UCLA, 10833 Le Conte Ave., Los Angeles, CA 90095-1690, USA; Department of Pathology, David Geffen School of Medicine at UCLA, 10833 Le Conte Ave., Los Angeles, CA 90095-1690, USA.
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine at UCLA, 10833 Le Conte Ave., Los Angeles, CA 90095-1690, USA
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2
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Potenciano da Silva KL, Moraes D, Lechner B, Lindner H, Haas H, Almeida Soares CM, Silva-Bailão MG, Bailão AM. Fonsecaea pedrosoi produces ferricrocin and can utilize different host iron sources. Fungal Biol 2023; 127:1512-1523. [PMID: 38097325 DOI: 10.1016/j.funbio.2023.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 07/08/2023] [Accepted: 07/10/2023] [Indexed: 12/18/2023]
Abstract
The survival of living organisms depends on iron, one of the most abundant metals in the Earth's crust. Nevertheless, this micronutrient is poorly available in our aerobic atmosphere as well as inside the mammalian host. This problem is circumvented by the expression of high affinity iron uptake machineries, including the production of siderophores, in pathogenic fungi. Here we demonstrated that F. pedrosoi, the causative agent of the neglected tropical disease chromoblastomycosis, presents gene clusters for siderophore production. In addition, ten putative siderophore transporters were identified. Those genes are upregulated under iron starvation, a condition that induces the secretion of hydroxamates, as revealed by chrome azurol S assays. RP-HPLC and mass spectrometry analysis allowed the identification of ferricrocin as an intra- and extracellular siderophore. F. pedrosoi can grow in different iron sources, including the bacterial ferrioxamine B and the host proteins ferritin, hemoglobin and holotransferrin. Of note, addition of hemoglobin, lactoferrin and holotransferrin to the growth medium of macrophages infected with F. pedrosoi enhanced significantly fungal survival. The ability to produce siderophores in iron limited conditions added to the versatility to utilize different sources of iron are strategies that certainly may contribute to fungal survival inside the host.
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Affiliation(s)
| | - Dayane Moraes
- Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
| | - Beatrix Lechner
- Institute of Molecular Biology/ Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
| | - Herbert Lindner
- Institute of Medical Biochemistry/Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
| | - Hubertus Haas
- Institute of Molecular Biology/ Biocenter, Medical University of Innsbruck, Innsbruck, Austria.
| | | | | | - Alexandre Melo Bailão
- Instituto de Ciências Biológicas, Universidade Federal de Goiás, Goiânia, Goiás, Brazil.
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3
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Alselami A, Drummond RA. How metals fuel fungal virulence, yet promote anti-fungal immunity. Dis Model Mech 2023; 16:dmm050393. [PMID: 37905492 PMCID: PMC10629672 DOI: 10.1242/dmm.050393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2023] Open
Abstract
Invasive fungal infections represent a significant global health problem, and present several clinical challenges, including limited treatment options, increasing rates of antifungal drug resistance and compounding comorbidities in affected patients. Metals, such as copper, iron and zinc, are critical for various biological and cellular processes across phyla. In mammals, these metals are important determinants of immune responses, but pathogenic microbes, including fungi, also require access to these metals to fuel their own growth and drive expression of major virulence traits. Therefore, host immune cells have developed strategies to either restrict access to metals to induce starvation of invading pathogens or deploy toxic concentrations within phagosomes to cause metal poisoning. In this Review, we describe the mechanisms regulating fungal scavenging and detoxification of copper, iron and zinc and the importance of these mechanisms for virulence and infection. We also outline how these metals are involved in host immune responses and the consequences of metal deficiencies or overloads on how the host controls invasive fungal infections.
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Affiliation(s)
- Alanoud Alselami
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
| | - Rebecca A. Drummond
- Institute of Immunology and Immunotherapy, University of Birmingham, Birmingham, B15 2TT, UK
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4
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Downes SG, Doyle S, Jones GW, Owens RA. Gliotoxin and related metabolites as zinc chelators: implications and exploitation to overcome antimicrobial resistance. Essays Biochem 2023; 67:769-780. [PMID: 36876884 PMCID: PMC10500201 DOI: 10.1042/ebc20220222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/03/2023] [Accepted: 02/06/2023] [Indexed: 03/07/2023]
Abstract
Antimicrobial resistance (AMR) is a major global problem and threat to humanity. The search for new antibiotics is directed towards targeting of novel microbial systems and enzymes, as well as augmenting the activity of pre-existing antimicrobials. Sulphur-containing metabolites (e.g., auranofin and bacterial dithiolopyrrolones [e.g., holomycin]) and Zn2+-chelating ionophores (PBT2) have emerged as important antimicrobial classes. The sulphur-containing, non-ribosomal peptide gliotoxin, biosynthesised by Aspergillus fumigatus and other fungi exhibits potent antimicrobial activity, especially in the dithiol form (dithiol gliotoxin; DTG). Specifically, it has been revealed that deletion of the enzymes gliotoxin oxidoreductase GliT, bis-thiomethyltransferase GtmA or the transporter GliA dramatically sensitise A. fumigatus to gliotoxin presence. Indeed, the double deletion strain A. fumigatus ΔgliTΔgtmA is especially sensitive to gliotoxin-mediated growth inhibition, which can be reversed by Zn2+ presence. Moreover, DTG is a Zn2+ chelator which can eject zinc from enzymes and inhibit activity. Although multiple studies have demonstrated the potent antibacterial effect of gliotoxin, no mechanistic details are available. Interestingly, reduced holomycin can inhibit metallo-β-lactamases. Since holomycin and gliotoxin can chelate Zn2+, resulting in metalloenzyme inhibition, we propose that this metal-chelating characteristic of these metabolites requires immediate investigation to identify new antibacterial drug targets or to augment the activity of existing antimicrobials. Given that (i) gliotoxin has been shown in vitro to significantly enhance vancomycin activity against Staphylococcus aureus, and (ii) that it has been independently proposed as an ideal probe to dissect the central 'Integrator' role of Zn2+ in bacteria - we contend such studies are immediately undertaken to help address AMR.
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Affiliation(s)
- Shane G Downes
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Sean Doyle
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
| | - Gary W Jones
- Centre for Biomedical Science Research, School of Health, Leeds Beckett University, Leeds LS1 3HE, U.K
| | - Rebecca A Owens
- Department of Biology, Maynooth University, Maynooth, Co. Kildare, Ireland
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5
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Enriquez KT, Plummer WD, Neufer PD, Chazin WJ, Dupont WD, Skaar EP. Temporal modelling of the biofilm lifecycle (TMBL) establishes kinetic analysis of plate-based bacterial biofilm dynamics. J Microbiol Methods 2023; 212:106808. [PMID: 37595876 PMCID: PMC10528067 DOI: 10.1016/j.mimet.2023.106808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 08/12/2023] [Accepted: 08/12/2023] [Indexed: 08/20/2023]
Abstract
Bacterial biofilms are critical to pathogenesis and infection. They are associated with rising rates of antimicrobial resistance. Biofilms are correlated with worse clinical outcomes, making them important to infectious diseases research. There is a gap in knowledge surrounding biofilm kinetics and dynamics which makes biofilm research difficult to translate from bench to bedside. To address this gap, this work employs a well-characterized crystal violet biomass accrual and planktonic cell density assay across a clinically relevant time course and expands statistical analysis to include kinetic information in a protocol termed the TMBL (Temporal Mapping of the Biofilm Lifecycle) assay. TMBL's statistical framework quantitatively compares biofilm communities across time, species, and media conditions in a 96-well format. Measurements from TMBL can reliably be condensed into response features that inform the time-dependent behavior of adherent biomass and planktonic cell populations. Staphylococcus aureus and Pseudomonas aeruginosa biofilms were grown in conditions of metal starvation in nutrient-variable media to demonstrate the rigor and translational potential of this strategy. Significant differences in single-species biofilm formation are seen in metal-deplete conditions as compared to their controls which is consistent with the consensus literature on nutritional immunity that metal availability drives transcriptomic and metabolomic changes in numerous pathogens. Taken together, these results suggest that kinetic analysis of biofilm by TMBL represents a statistically and biologically rigorous approach to studying the biofilm lifecycle as a time-dependent process. In addition to current methods to study the impact of microbe and environmental factors on the biofilm lifecycle, this kinetic assay can inform biological discovery in biofilm formation and maintenance.
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Affiliation(s)
- Kyle T Enriquez
- Vanderbilt University Medical Scientist Training Program, Vanderbilt University School of Medicine, Nashville, TN, United States of America; Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN, United States of America; Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - W Dale Plummer
- Department of Biostatistics, Vanderbilt University, Nashville, TN, United States of America
| | - Preston D Neufer
- Department of Chemistry, Vanderbilt University, Nashville, TN, United States of America; Department of Biochemistry, Vanderbilt University, Nashville, TN, United States of America
| | - Walter J Chazin
- Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, United States of America; Department of Chemistry, Vanderbilt University, Nashville, TN, United States of America; Department of Biochemistry, Vanderbilt University, Nashville, TN, United States of America
| | - William D Dupont
- Department of Biostatistics, Vanderbilt University, Nashville, TN, United States of America
| | - Eric P Skaar
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University, Nashville, TN, United States of America; Vanderbilt Institute for Infection, Immunology, and Inflammation, Vanderbilt University Medical Center, Nashville, TN, United States of America.
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6
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Djoko KY. Control of nutrient metal availability during host-microbe interactions: beyond nutritional immunity. J Biol Inorg Chem 2023:10.1007/s00775-023-02007-z. [PMID: 37464157 PMCID: PMC10368554 DOI: 10.1007/s00775-023-02007-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/28/2023] [Indexed: 07/20/2023]
Abstract
The control of nutrient availability is an essential ecological function of the host organism in host-microbe systems. Although often overshadowed by macronutrients such as carbohydrates, micronutrient metals are known as key drivers of host-microbe interactions. The ways in which host organisms control nutrient metal availability are dictated by principles in bioinorganic chemistry. Here I ponder about the actions of metal-binding molecules from the host organism in controlling nutrient metal availability to the host microbiota. I hope that these musings will encourage new explorations into the fundamental roles of metals in the ecology of diverse host-microbe systems.
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Affiliation(s)
- Karrera Y Djoko
- Department of Biosciences, Durham University, Durham, DH1 3LE, UK.
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7
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Abbondante S, Leal SM, Clark HL, Ratitong B, Sun Y, Ma LJ, Pearlman E. Immunity to pathogenic fungi in the eye. Semin Immunol 2023; 67:101753. [PMID: 37060806 PMCID: PMC10508057 DOI: 10.1016/j.smim.2023.101753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Indexed: 04/17/2023]
Abstract
Fusarium, Aspergillus and Candida are important fungal pathogens that cause visual impairment and blindness in the USA and worldwide. This review will summarize the epidemiology and clinical features of corneal infections and discuss the immune and inflammatory responses that play an important role in clinical disease. In addition, we describe fungal virulence factors that are required for survival in infected corneas, and the activities of neutrophils in fungal killing, tissue damage and cytokine production.
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Affiliation(s)
- Serena Abbondante
- Department of Ophthalmology, and Department of Physiology and Biophysics, University of California, Irvine, CA, USA
| | - Sixto M Leal
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA
| | | | - Bridget Ratitong
- Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Yan Sun
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA
| | - Li-Jun Ma
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA, USA
| | - Eric Pearlman
- Department of Ophthalmology, and Department of Physiology and Biophysics, University of California, Irvine, CA, USA.
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8
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XUE P, SÁNCHEZ-LEÓN E, DAMOO D, HU G, JUNG WH, KRONSTAD JW. Heme sensing and trafficking in fungi. FUNGAL BIOL REV 2023; 43:100286. [PMID: 37781717 PMCID: PMC10540271 DOI: 10.1016/j.fbr.2022.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Fungal pathogens cause life-threatening diseases in humans, and the increasing prevalence of these diseases emphasizes the need for new targets for therapeutic intervention. Nutrient acquisition during infection is a promising target, and recent studies highlight the contributions of endomembrane trafficking, mitochondria, and vacuoles in the sensing and acquisition of heme by fungi. These studies have been facilitated by genetically encoded biosensors and other tools to quantitate heme in subcellular compartments and to investigate the dynamics of trafficking in living cells. In particular, the applications of biosensors in fungi have been extended beyond the detection of metabolites, cofactors, pH, and redox status to include the detection of heme. Here, we focus on studies that make use of biosensors to examine mechanisms of heme uptake and degradation, with guidance from the model fungus Saccharomyces cerevisiae and an emphasis on the pathogenic fungi Candida albicans and Cryptococcus neoformans that threaten human health. These studies emphasize a role for endocytosis in heme uptake, and highlight membrane contact sites involving mitochondria, the endoplasmic reticulum and vacuoles as mediators of intracellular iron and heme trafficking.
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Affiliation(s)
- Peng XUE
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eddy SÁNCHEZ-LEÓN
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Djihane DAMOO
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Guanggan HU
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Won Hee JUNG
- Department of Systems Biotechnology, Chung-Ang University, Anseong 17546, Korea
| | - James W. KRONSTAD
- Michael Smith Laboratories, Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia, Canada
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9
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Abstract
Human calprotectin (CP, S100A8/S100A9 oligomer) is an abundant neutrophil protein that contributes to innate immunity by sequestering nutrient metal ions in the extracellular space. This process starves invading microbial pathogens of essential metal nutrients, which can inhibit growth and colonization. Over the past decade, fundamental and clinical studies have revealed that the S100A8 and S100A9 subunits of CP exhibit a variety of post-translational modifications (PTMs). This review summarizes PTMs on the CP subunits that have been detected and highlights two recent studies that evaluated the structural and functional consequences of methionine and cysteine oxidation on CP. Collectively, these investigations indicate that the molecular speciation of extracellular CP is complex and composed of multiple proteoforms. Moreover, PTMs may impact biological function and the lifetime of the protein. It is therefore important that post-translationally modified CP species receive consideration and integration into the current working model for how CP functions in nutritional immunity.
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10
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Mandal SK, Kanaujia SP. Role of an orphan substrate-binding protein MhuP in transient heme transfer in Mycobacterium tuberculosis. Int J Biol Macromol 2022; 211:342-356. [PMID: 35569676 DOI: 10.1016/j.ijbiomac.2022.05.059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/25/2022] [Accepted: 05/08/2022] [Indexed: 11/25/2022]
Abstract
The redox property of iron makes it an essential cofactor for numerous enzymes involved in various metabolic processes. In vertebrates, iron is attached to either heme molecules or with other circulatory proteins, making its accessibility restricted for bacterial pathogens residing inside the host. Due to this importance, there is always an ongoing battle between the host system and pathogens, known as nutritional immunity. To capture the bound iron from the human hosts, intracellular pathogens like Mycobacterium tuberculosis secrete siderophore molecules which are ultimately uptaken by versatile transport machinery such as ATP-binding cassette (ABC) transporters. Earlier reports have suggested the presence of a heme uptake protein MhuP (ORF id: Rv0265c) in M. tuberculosis, which transiently transfers the bound iron to the protein DppA for further heme transport by utilizing its cognate transport machinery (DppBCD). In the present study, we report the crystal structure of MhuP. The binding experiments of heme with MhuP suggest its specific nature. Molecular docking studies confirm the binding of the protein MhuP with heme as well as to the protein DppA. Thus, the results indicate the binding of heme to MhuP and its probable transient transport via the DppABCD transport system in M. tuberculosis.
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Affiliation(s)
- Suraj Kumar Mandal
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India
| | - Shankar Prasad Kanaujia
- Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781039, Assam, India.
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11
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Deng Q, Yang S, Sun L, Huang K, Dong K, Zhu Y, Cao Y, Li Y, Wu S, Huang R. A detrimental role of NLRP6 in host iron metabolism during Salmonella infection. Redox Biol 2021; 49:102217. [PMID: 34942528 DOI: 10.1016/j.redox.2021.102217] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/17/2021] [Accepted: 12/17/2021] [Indexed: 11/27/2022] Open
Abstract
Maintaining host iron homeostasis is an essential component of nutritional immunity responsible for sequestrating iron from pathogens and controlling infection. Nucleotide-oligomerization domain-like receptors (NLRs) contribute to cytoplasmic sensing and antimicrobial response orchestration. However, it remains unknown whether and how NLRs may regulate host iron metabolism, an important component of nutritional immunity. Here, we demonstrated that NLRP6, a member of the NLR family, has an unconventional role in regulating host iron metabolism that perturbs host resistance to bacterial infection. NLRP6 deficiency is advantageous for maintaining cellular iron homeostasis in both macrophages and enterocytes through increasing the unique iron exporter ferroportin-mediated iron efflux in a nuclear factor erythroid-derived 2–related factor 2 (NRF2)-dependent manner. Additional studies uncovered a novel mechanism underlying NRF2 regulation and operating through NLRP6/AKT interaction and that causes a decrease in AKT phosphorylation, which in turn reduces NRF2 nuclear translocation. In the absence of NLRP6, increased AKT activation promotes NRF2/KEAP1 dissociation via increasing mTOR-mediated p62 phosphorylation and downregulates KEAP1 transcription by promoting FOXO3A phosphorylation. Together, our observations provide new insights into the mechanism of nutritional immunity by revealing a novel function of NLRP6 in regulating iron metabolism, and suggest NLRP6 as a therapeutic target for limiting bacterial iron acquisition.
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12
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Abstract
Fungal pathogens now account for an unprecedented burden on human health. Like all microorganisms, these fungi must successfully forage for essential micronutrients such as zinc in order to proliferate. However, pathogenic microbes face an additional hurdle in securing zinc from their environment: the action of host nutritional immunity which strictly manipulates microbial access to this essential, but also potentially toxic trace metal. This review introduces the relevant pathogenic species and goes on to cover the molecular mechanisms of zinc uptake by human fungal pathogens. Fungi scavenge zinc from their environment via two basic mechanisms: via a family of cellular zinc importers-the ZIP transporters; and via a unique secreted zinc binding protein-the zincophore. However the genetic requirement of these systems for fungal virulence is highly species-specific. As well as zinc scarcity, potential intoxification with this heavy metal can occur and, unlike bacteria, fungi deal with environmental insult this via intraorganellar compartmentalization. Zinc availability also modulates the morphogenic behavior of a subset of pathogenic yeast species. This chapter will cover these different aspects of zinc availability on the physiology of human fungal pathogens with emphasis on the major pathogenic species Candida albicans.
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Affiliation(s)
- Duncan Wilson
- Medical Research Council Centre for Medical Mycology, University of Exeter, Exeter, United Kingdom.
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13
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Abstract
Transition metals, such as Zn2+, are essential dietary constituents of all biological life, including mammalian hosts and the pathogens that infect them. Therefore, to thrive and cause infection, pathogens must successfully assimilate these elements from the host milieu. Consequently, mammalian immunity has evolved to actively restrict and/or pool metals to toxic concentrations in an effort to attenuate microbial pathogenicity - a process termed nutritional immunity. Despite host-induced Zn2+ nutritional immunity, pathogens such as Candida albicans, are still capable of causing disease and thus must be equipped with robust Zn2+ sensory, uptake and detoxification machinery. This review will discuss the strategies employed by mammalian hosts to limit Zn2+ during infection, and the subsequent fungal interventions that counteract Zn2+ nutritional immunity.
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Affiliation(s)
- Omran F Alamir
- Department of Natural Sciences, College of Health Sciences, The Public Authority for Applied Education and Training, Al Asimah, Kuwait
| | - Rita O Oladele
- Department of Medical Microbiology & Parasitology, College of Medicine, University of Lagos, Lagos State, Nigeria
| | - C Ibe
- Department of Microbiology, Abia State University, PMB 2000, Uturu, Abia State, Nigeria
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Healy C, Munoz-Wolf N, Strydom J, Faherty L, Williams NC, Kenny S, Donnelly SC, Cloonan SM. Nutritional immunity: the impact of metals on lung immune cells and the airway microbiome during chronic respiratory disease. Respir Res 2021; 22:133. [PMID: 33926483 DOI: 10.1186/s12931-021-01722-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 04/15/2021] [Indexed: 12/15/2022] Open
Abstract
Nutritional immunity is the sequestration of bioavailable trace metals such as iron, zinc and copper by the host to limit pathogenicity by invading microorganisms. As one of the most conserved activities of the innate immune system, limiting the availability of free trace metals by cells of the immune system serves not only to conceal these vital nutrients from invading bacteria but also operates to tightly regulate host immune cell responses and function. In the setting of chronic lung disease, the regulation of trace metals by the host is often disrupted, leading to the altered availability of these nutrients to commensal and invading opportunistic pathogenic microbes. Similarly, alterations in the uptake, secretion, turnover and redox activity of these vitally important metals has significant repercussions for immune cell function including the response to and resolution of infection. This review will discuss the intricate role of nutritional immunity in host immune cells of the lung and how changes in this fundamental process as a result of chronic lung disease may alter the airway microbiome, disease progression and the response to infection.
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15
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Zong X, Fu J, Xu B, Wang Y, Jin M. Interplay between gut microbiota and antimicrobial peptides. Anim Nutr 2020; 6:389-396. [PMID: 33364454 PMCID: PMC7750803 DOI: 10.1016/j.aninu.2020.09.002] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/09/2020] [Accepted: 09/14/2020] [Indexed: 12/19/2022]
Abstract
The gut microbiota is comprised of a diverse array of microorganisms that interact with immune system and exert crucial roles for the health. Changes in the gut microbiota composition and functionality are associated with multiple diseases. As such, mobilizing a rapid and appropriate antimicrobial response depending on the nature of each stimulus is crucial for maintaining the balance between homeostasis and inflammation in the gut. Major players in this scenario are antimicrobial peptides (AMP), which belong to an ancient defense system found in all organisms and participate in a preservative co-evolution with a complex microbiome. Particularly increasing interactions between AMP and microbiota have been found in the gut. Here, we focus on the mechanisms by which AMP help to maintain a balanced microbiota and advancing our understanding of the circumstances of such balanced interactions between gut microbiota and host AMP. This review aims to provide a comprehensive overview on the interplay of diverse antimicrobial responses with enteric pathogens and the gut microbiota, which should have therapeutic implications for different intestinal disorders.
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Affiliation(s)
- Xin Zong
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Animal Nutrition and Feed Science in Eastern China, Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Jie Fu
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Animal Nutrition and Feed Science in Eastern China, Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Bocheng Xu
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Animal Nutrition and Feed Science in Eastern China, Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Yizhen Wang
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Animal Nutrition and Feed Science in Eastern China, Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
| | - Mingliang Jin
- Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
- Key Laboratory of Animal Nutrition and Feed Science in Eastern China, Ministry of Agriculture, College of Animal Sciences, Zhejiang University, Hangzhou 310058, China
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16
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Abstract
Iron is an essential micronutrient for virtually all living cells. In infectious diseases, both invading pathogens and mammalian cells including those of the immune system require iron to sustain their function, metabolism and proliferation. On the one hand, microbial iron uptake is linked to the virulence of most human pathogens. On the other hand, the sequestration of iron from bacteria and other microorganisms is an efficient strategy of host defense in line with the principles of 'nutritional immunity'. In an acute infection, host-driven iron withdrawal inhibits the growth of pathogens. Chronic immune activation due to persistent infection, autoimmune disease or malignancy however, sequesters iron not only from infectious agents, autoreactive lymphocytes and neoplastic cells but also from erythroid progenitors. This is one of the key mechanisms which collectively result in the anemia of chronic inflammation. In this review, we highlight the most important interconnections between iron metabolism and immunity, focusing on host defense against relevant infections and on the clinical consequences of anemia of inflammation.
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Affiliation(s)
- Manfred Nairz
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine II, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria; Christian Doppler Laboratory for Iron Metabolism and Anemia Research, Medical University of Innsbruck, Austria.
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Cross JH, Jarjou O, Mohammed NI, Rayment Gomez S, Touray BJB, Prentice AM, Cerami C. Early postnatal hypoferremia in low birthweight and preterm babies: A prospective cohort study in hospital-delivered Gambian neonates. EBioMedicine 2020; 52:102613. [PMID: 31981986 PMCID: PMC6992934 DOI: 10.1016/j.ebiom.2019.102613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 11/29/2019] [Accepted: 12/17/2019] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Neonates, particularly those born preterm (PTB) and with low birthweight (LBW), are especially susceptible to bacterial and fungal infections that cause an estimated 225,000 deaths annually. Iron is a vital nutrient for the most common organisms causing septicaemia. Full-term babies elicit an immediate postnatal hypoferremia assumed to have evolved as an innate defence. We tested whether PTB and LBW babies are capable of the same response. METHODS We conducted an observational study of 152 babies who were either PTB (born ≥32 to <37 weeks gestational age) and/or LBW (<2500 g) (PTB/LBW) and 278 term, normal-weight babies (FTB/NBW). Blood was sampled from the umbilical cord vein and artery, and matched venous blood samples were taken from all neonates between 6-24 h after delivery. We measured haematological, iron and inflammatory markers. FINDINGS In both PTB/LBW and FTB/NBW babies, serum iron decreased 3-fold within 12 h of delivery compared to umbilical blood (7·5 ± 4·5 vs 23·3 ± 7·1 ng/ml, P < 0·001, n = 425). Transferrin saturation showed a similar decline with a consequent increase in unsaturated iron-binding capacity. C-reactive protein levels increased over 10-fold (P < 0·001) and hepcidin levels doubled (P < 0·001). There was no difference in any of these responses between PTB/LBW and FTB/NBW babies. INTERPRETATION Premature or low birthweight babies are able to mount a very rapid hypoferremia that is indistinguishable from that in normal term babies. The data suggest that this is a hepcidin-mediated response triggered by acute inflammation at birth, and likely to have evolved as an innate immune response against bacterial and fungal septicaemia. TRIAL REGISTRATION clinicaltrials.gov (NCT03353051). Registration date: November 27, 2017. FUNDING Bill & Melinda Gates Foundation (OPP1152353).
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Affiliation(s)
- James H Cross
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, P.O. Box 273, Banjul, The Gambia
| | - Ousman Jarjou
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, P.O. Box 273, Banjul, The Gambia
| | - Nuredin Ibrahim Mohammed
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, P.O. Box 273, Banjul, The Gambia
| | | | - Bubacarr J B Touray
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, P.O. Box 273, Banjul, The Gambia
| | - Andrew M Prentice
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, P.O. Box 273, Banjul, The Gambia
| | - Carla Cerami
- Medical Research Council Unit The Gambia at the London School of Hygiene & Tropical Medicine, Atlantic Boulevard, Fajara, P.O. Box 273, Banjul, The Gambia.
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18
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Cui K, Li Q, Xu D, Zhang J, Gao S, Xu W, Mai K, Ai Q. Establishment and characterization of two head kidney macrophage cell lines from large yellow croaker (Larimichthys crocea). Dev Comp Immunol 2020; 102:103477. [PMID: 31470020 DOI: 10.1016/j.dci.2019.103477] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 08/22/2019] [Accepted: 08/22/2019] [Indexed: 06/10/2023]
Abstract
Two continuous macrophage cell lines (LCM07 and LCM10) were established for the first time from the head kidney of the marine fish large yellow croaker (Larimichthys crocea). To date, both cell lines have been subcultured for more than 100 passages in 12 months. Notably, the LCM07 and LCM10 cells have distinct morphology and immune function. LCM07 cells showed strong contact inhibition in crowded conditions, while this was not observed in the LCM10 cells because they could grow in an overlapping manner. Correspondingly, LCM10 cells were slenderer than LCM07 cells. LCM07 cells had stronger phagocytic ability than LCM10 cells, while LCM10 cells had stronger respiratory burst activity after incubation with lipopolysaccharide (LPS) and phorbol ester (PMA). LCM07 cells had stronger Escherichia coli killing ability than LCM10 cells. The mRNA of macrophage markers, namely that of CD11b, CD114, CD68, CD86, CD209, and CD163, were all expressed in primary macrophages as well as the two cell lines. The mRNA expression levels of selected inflammatory cytokines, namely interleukin (IL)-1β, IL-8, and tumor necrosis factor (TNF)α, were all upregulated after incubation with LPS. LPS also regulated key components of the mitogen-activated protein kinase (MAPK) signaling pathway, i.e., p38, ERK (extracellular signal-regulated kinase), and JNK (Jun N-terminal kinase) and their phosphorylated forms. Arachidonic acid (ARA) downregulated the LPS-induced upregulation of IL-1β, IL-8, and TNFα, revealing that LCM07 and LCM10 cells are useful for studying nutritional immunity. In conclusion, two distinct macrophage cell lines have been established for the first time from the head kidney of marine fish, which could be useful for studying immunity and nutritional immunity.
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Affiliation(s)
- Kun Cui
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong, 266237, PR China
| | - Qingfei Li
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong, 266237, PR China
| | - Dan Xu
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong, 266237, PR China
| | - Junzhi Zhang
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong, 266237, PR China
| | - Shengnan Gao
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong, 266237, PR China
| | - Wei Xu
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong, 266237, PR China
| | - Kangsen Mai
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong, 266237, PR China
| | - Qinghui Ai
- Key Laboratory of Aquaculture Nutrition and Feed, Ministry of Agriculture, The Key Laboratory of Mariculture, Ministry of Education, Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China; Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, 1 Wenhai Road, Qingdao, Shandong, 266237, PR China.
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Chung LK, Raffatellu M. G.I. pros: Antimicrobial defense in the gastrointestinal tract. Semin Cell Dev Biol 2019; 88:129-137. [PMID: 29432952 PMCID: PMC6087682 DOI: 10.1016/j.semcdb.2018.02.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 02/06/2018] [Accepted: 02/06/2018] [Indexed: 01/11/2023]
Abstract
The gastrointestinal tract is a complex environment in which the host immune system interacts with a diverse array of microorganisms, both symbiotic and pathogenic. As such, mobilizing a rapid and appropriate antimicrobial response depending on the nature of each stimulus is crucial for maintaining the balance between homeostasis and inflammation in the gut. Here we focus on the mechanisms by which intestinal antimicrobial peptides regulate microbial communities during dysbiosis and infection. We also discuss classes of bacterial peptides that contribute to reducing enteric pathogen outgrowth. This review aims to provide a comprehensive overview on the interplay of diverse antimicrobial responses with enteric pathogens and the gut microbiota.
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Affiliation(s)
- Lawton K Chung
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California, San Diego, La Jolla, CA, 92093-0704, United States
| | - Manuela Raffatellu
- Department of Pediatrics, Division of Host-Microbe Systems and Therapeutics, University of California, San Diego, La Jolla, CA, 92093-0704, United States; Chiba University-UC San Diego Center for Mucosal Immunology, Allergy, and Vaccines (CU-UCSD cMAV), La Jolla CA, United States.
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20
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Abstract
S100 proteins are distinct dimeric EF-hand Ca2+-binding proteins that can bind Zn2+, Mn2+, and other transition metals with high affinity at two sites in the dimer interface. Certain S100 proteins, including S100A7, S100A12, S100A8, and S100A9, play key roles in the innate immune response to pathogens. These proteins function via a "nutritional immunity" mechanism by depleting essential transition metals in the infection that are required for the invading organism to grow and thrive. They also act as damage-associated molecular pattern ligands, which activate pattern recognition receptors (e.g., Toll-like receptor 4, RAGE) that mediate inflammation. Here we present protocols for these S100 proteins for high-level production of recombinant protein, measurement of binding affinities using isothermal titration calorimetry, and an assay of antimicrobial activity.
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Abstract
Nutritional immunity describes mechanisms for withholding essential transition metals as well as directing the toxicity of these metals against infectious agents. Zinc is one of these transition elements that are essential for both humans and microbial pathogens. At the same time, Zn can be toxic both for man and microbes if its concentration is higher than the tolerance limit. Therefore a "delicate" balance of Zn must be maintained to keep the immune cells surveilling while making the level of Zn either to starve or to intoxicate the pathogens. On the other hand, the invading pathogens will exploit the host Zn pool for its survival and replication. Apparently, different sets of protein in human and bacteria are involved to maintain their Zn need. Metallothionein (MT)-a group of low molecular weight proteins, is well known for its Zn-binding ability and is expected to play an important role in that Zn balance at the time of active infection. However, the differences in structural, functional, and molecular control of biosynthesis between human and bacterial MT might play an important role to determine the proper use of Zn and the winning side. The current review explains the possible involvement of human and bacterial MT at the time of infection to control and exploit Zn for their need.
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Abstract
The ability to cause disease extends from the ability to grow within the host environment. The human host provides a dynamic environment to which fungal pathogens must adapt to in order to survive. The ability to grow under a particular condition (i.e., the ability to grow at mammalian body temperature) is considered a fitness attribute and is essential for growth within the human host. On the other hand, some environmental conditions activate signaling mechanisms resulting in the expression of virulence factors, which aid pathogenicity. Therefore, pathogenic fungi have evolved fitness and virulence attributes to enable them to colonize and infect humans. This review highlights how some of the major pathogenic fungi respond and adapt to key environmental signals within the human host.
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Affiliation(s)
- Sarah L Sherrington
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Pizga Kumwenda
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Courtney Kousser
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom
| | - Rebecca A Hall
- Institute for Microbiology and Infection, School of Biosciences, University of Birmingham, Birmingham, United Kingdom.
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23
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Sprenger M, Kasper L, Hensel M, Hube B. Metabolic adaptation of intracellular bacteria and fungi to macrophages. Int J Med Microbiol 2017; 308:215-227. [PMID: 29150190 DOI: 10.1016/j.ijmm.2017.11.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Revised: 09/21/2017] [Accepted: 11/05/2017] [Indexed: 02/07/2023] Open
Abstract
The mature phagosome of macrophages is a hostile environment for the vast majority of phagocytosed microbes. In addition to active destruction of the engulfed microbes by antimicrobial compounds, restriction of essential nutrients in the phagosomal compartment contributes to microbial growth inhibition and killing. However, some pathogenic microorganisms have not only developed various strategies to efficiently withstand or counteract antimicrobial activities, but also to acquire nutrients within macrophages for intracellular replication. Successful intracellular pathogens are able to utilize host-derived amino acids, carbohydrates and lipids as well as trace metals and vitamins during intracellular growth. This requires sophisticated strategies such as phagosome modification or escape, efficient nutrient transporters and metabolic adaptation. In this review, we discuss the metabolic adaptation of facultative intracellular bacteria and fungi to the intracellular lifestyle inside macrophages.
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Affiliation(s)
- Marcel Sprenger
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Lydia Kasper
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany
| | - Michael Hensel
- Division of Microbiology, University Osnabrück, Osnabrück, Germany
| | - Bernhard Hube
- Department of Microbial Pathogenicity Mechanisms, Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knoell-Institute, Jena, Germany; Friedrich Schiller University, Jena, Germany; Center for Sepsis Control and Care, University Hospital, Jena, Germany.
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24
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Niemiec MJ, Grumaz C, Ermert D, Desel C, Shankar M, Lopes JP, Mills IG, Stevens P, Sohn K, Urban CF. Dual transcriptome of the immediate neutrophil and Candida albicans interplay. BMC Genomics 2017; 18:696. [PMID: 28874114 PMCID: PMC5585943 DOI: 10.1186/s12864-017-4097-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 08/30/2017] [Indexed: 12/23/2022] Open
Abstract
Background Neutrophils are traditionally considered transcriptionally inactive. Compared to other immune cells, little is known about their transcriptional profile during interaction with pathogens. Methods We analyzed the meta-transcriptome of the neutrophil-Candida albicans interplay and the transcriptome of C. albicans challenged with neutrophil extracellular traps (NETs) by RNA-Seq, considering yeast and hypha individually in each approach. Results The neutrophil response to C. albicans yeast and hyphae was dominated by a morphotype-independent core response. However, 11 % of all differentially expressed genes were regulated in a specific manner when neutrophils encountered the hyphal form of C. albicans. While involving genes for transcriptional regulators, receptors, and cytokines, the neutrophil core response lacked typical antimicrobial effectors genes. Genes of the NOD-like receptor pathway, including NLRP3, were enriched. Neutrophil- and NET-provoked responses in C. albicans differed. At the same time, the Candida transcriptome upon neutrophil encounter and upon NET challenge included genes from various metabolic processes and indicate a mutual role of the regulators Tup1p, Efg1p, Hap43p, and Cap1p. Upon challenge with neutrophils and NETs, the overall Candida response was partially morphotype-specific. Yet again, actual oppositional regulation in yeasts and hyphae was only detected for the arginine metabolism in neutrophil-infecting C. albicans. Conclusions Taken together, our study provides a comprehensive and quantitative transcript profile of the neutrophil–C. albicans interaction. By considering the two major appearances of both, neutrophils and C. albicans, our study reveals yet undescribed insights into this medically relevant encounter. Hence, our findings will facilitate future research and potentially inspire novel therapy developments. Electronic supplementary material The online version of this article (10.1186/s12864-017-4097-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Maria J Niemiec
- Department of Clinical Microbiology, Umeå Centre for Microbial Research (UCMR) & Laboratory of Molecular Infection Medicine Sweden (MIMS), Umeå University, Umea, Sweden.,Present Address: Leibniz Institute for Natural Product Research and Infection Biology - Hans Knöll Institute (HKI), Jena, Germany & Center for Sepsis Control and Care (CSCC), Jena, Germany
| | - Christian Grumaz
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, Germany
| | - David Ermert
- Department of Clinical Microbiology, Umeå Centre for Microbial Research (UCMR) & Laboratory of Molecular Infection Medicine Sweden (MIMS), Umeå University, Umea, Sweden.,Present Address: Division of Medical Protein Chemistry, Department of Translational Medicine, Lund University, Malmö, Sweden
| | - Christiane Desel
- Institute of Clinical Microbiology, Immunology and Hygiene, University Hospital Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany.,Present Address: The Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Madhu Shankar
- Department of Clinical Microbiology, Umeå Centre for Microbial Research (UCMR) & Laboratory of Molecular Infection Medicine Sweden (MIMS), Umeå University, Umea, Sweden
| | - José Pedro Lopes
- Department of Clinical Microbiology, Umeå Centre for Microbial Research (UCMR) & Laboratory of Molecular Infection Medicine Sweden (MIMS), Umeå University, Umea, Sweden
| | - Ian G Mills
- Prostate Cancer Research Group, Center of Molecular Medicine Norway (NCMM), Oslo, Norway.,Department of Molecular Oncology, Institute of Cancer Research, Radium Hospital, Oslo, Norway.,PCUK/Movember Centre of Excellence for Prostate Cancer Research, Centre for Cancer Research and Cell Biology (CCRCB), Queen's University Belfast, Belfast, UK
| | - Philip Stevens
- University of Stuttgart IGVP, Stuttgart, Germany.,Center for Integrative Bioinformatics Vienna, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
| | - Kai Sohn
- Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB, Stuttgart, Germany
| | - Constantin F Urban
- Department of Clinical Microbiology, Umeå Centre for Microbial Research (UCMR) & Laboratory of Molecular Infection Medicine Sweden (MIMS), Umeå University, Umea, Sweden.
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25
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Makthal N, Nguyen K, Do H, Gavagan M, Chandrangsu P, Helmann JD, Olsen RJ, Kumaraswami M. A Critical Role of Zinc Importer AdcABC in Group A Streptococcus-Host Interactions During Infection and Its Implications for Vaccine Development. EBioMedicine 2017; 21:131-141. [PMID: 28596134 PMCID: PMC5514391 DOI: 10.1016/j.ebiom.2017.05.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 05/30/2017] [Accepted: 05/31/2017] [Indexed: 02/06/2023] Open
Abstract
Bacterial pathogens must overcome host immune mechanisms to acquire micronutrients for successful replication and infection. Streptococcus pyogenes, also known as group A streptococcus (GAS), is a human pathogen that causes a variety of clinical manifestations, and disease prevention is hampered by lack of a human GAS vaccine. Herein, we report that the mammalian host recruits calprotectin (CP) to GAS infection sites and retards bacterial growth by zinc limitation. However, a GAS-encoded zinc importer and a nuanced zinc sensor aid bacterial defense against CP-mediated growth inhibition and contribute to GAS virulence. Immunization of mice with the extracellular component of the zinc importer confers protection against systemic GAS challenge. Together, we identified a key early stage host-GAS interaction and translated that knowledge into a novel vaccine strategy against GAS infection. Furthermore, we provided evidence that a similar struggle for zinc may occur during other streptococcal infections, which raises the possibility of a broad-spectrum prophylactic strategy against multiple streptococcal pathogens. Host employs calprotectin to impose zinc (Zn) limitation on the human pathogen group A streptococcus (GAS) during infection. As a defense, GAS uses a sensor, AdcR, to monitor Zn availability, and a high-affinity transporter, AdcABC, to acquire Zn. Finally, we characterized the extracellular subunit of AdcA as a vaccine candidate to protect mice from GAS infections.
There is an urgent need for a human vaccine to protect against diseases caused by human pathogen, group A streptococcus (GAS). Herein, we identified the key molecular players involved in the battle between the host and invading bacteria for the critical nutrient zinc. The host recruits calprotectin at GAS infection sites to limit zinc availability to the pathogen. The pathogen senses the alterations in zinc availability using a sensor, AdcR, and outcompetes calprotectin by employing a high-affinity zinc uptake system, AdcABC. Using this knowledge, we developed a successful vaccination strategy by immunization with AdcA and demonstrated protection against GAS infections.
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Affiliation(s)
- Nishanth Makthal
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, United States
| | - Kimberly Nguyen
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, United States
| | - Hackwon Do
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, United States
| | - Maire Gavagan
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, United States
| | - Pete Chandrangsu
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, United States
| | - John D Helmann
- Department of Microbiology, Cornell University, Ithaca, NY 14853-8101, United States
| | - Randall J Olsen
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, United States
| | - Muthiah Kumaraswami
- Center for Molecular and Translational Human Infectious Diseases Research, Houston Methodist Research Institute, Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX 77030, United States.
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Neumann W, Hadley RC, Nolan EM. Transition metals at the host-pathogen interface: how Neisseria exploit human metalloproteins for acquiring iron and zinc. Essays Biochem 2017; 61:211-23. [PMID: 28487398 DOI: 10.1042/EBC20160084] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 03/06/2017] [Accepted: 03/13/2017] [Indexed: 12/17/2022]
Abstract
Transition metals are essential nutrients for all organisms and important players in the host-microbe interaction. During bacterial infection, a tug-of-war between the host and microbe for nutrient metals occurs: the host innate immune system responds to the pathogen by reducing metal availability and the pathogen tries to outmaneuver this response. The outcome of this competition, which involves metal-sequestering host-defense proteins and microbial metal acquisition machinery, is an important determinant for whether infection occurs. One strategy bacterial pathogens employ to overcome metal restriction involves hijacking abundant host metalloproteins. The obligate human pathogens Neisseria meningitidis and N. gonorrhoeae express TonB-dependent transport systems that capture human metalloproteins, extract the bound metal ions, and deliver these nutrients into the bacterial cell. This review highlights structural and mechanistic investigations that provide insights into how Neisseria acquire iron from the Fe(III)-transport protein transferrin (TF), the Fe(III)-chelating host-defense protein lactoferrin (LF), and the oxygen-transport protein hemoglobin (Hb), and obtain zinc from the metal-sequestering antimicrobial protein calprotectin (CP).
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Abstract
All living organisms require certain micronutrients such as iron, zinc, manganese and copper for cellular function and growth. For human pathogens however, the maintenance of metal ion homeostasis is particularly challenging. This is because the mammalian host actively enforces extremes of micronutrient availability on potential microbial invaders-processes collectively termed nutritional immunity. The role of iron sequestration in controlling microbial infections is well established and, more recently, the importance of other metals including zinc, manganese and copper has been recognised. In this chapter, we explore the nutritional immune mechanisms that defend the human body against fungal infections and the strategies that these important pathogens exploit to counteract nutritional immunity and thrive in the infected host.
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Affiliation(s)
- Dhara Malavia
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, United Kingdom
| | - Aaron Crawford
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, United Kingdom
| | - Duncan Wilson
- Aberdeen Fungal Group, MRC Centre for Medical Mycology, School of Medicine, Medical Sciences and Nutrition, University of Aberdeen, Institute of Medical Sciences, Foresterhill, United Kingdom.
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Hare SA. Diverse structural approaches to haem appropriation by pathogenic bacteria. Biochim Biophys Acta Proteins Proteom 2017; 1865:422-33. [PMID: 28130069 DOI: 10.1016/j.bbapap.2017.01.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Revised: 01/16/2017] [Accepted: 01/23/2017] [Indexed: 11/24/2022]
Abstract
The critical need for iron presents a challenge for pathogenic bacteria that must survive in an environment bereft of accessible iron due to a natural low bioavailability and their host's nutritional immunity. Appropriating haem, either direct from host haemoproteins or by secreting haem-scavenging haemophores, is one way pathogenic bacteria can overcome this challenge. After capturing their target, haem appropriation systems must remove haem from a high-affinity binding site (on the host haemoprotein or bacterial haemophore) and transfer it to a binding site of lower affinity on a bacterial receptor. Structural information is now available to show how, using a combination of induced structural changes and steric clashes, bacteria are able to extract haem from haemophores, haemopexin and haemoglobin. This review focuses on structural descriptions of these bacterial haem acquisition systems, summarising how they bind haem and their target haemoproteins with particularly emphasis on the mechanism of haem extraction.
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Subramanian Vignesh K, Deepe GS. Immunological orchestration of zinc homeostasis: The battle between host mechanisms and pathogen defenses. Arch Biochem Biophys 2016; 611:66-78. [PMID: 26921502 PMCID: PMC4996772 DOI: 10.1016/j.abb.2016.02.020] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 02/12/2016] [Accepted: 02/17/2016] [Indexed: 12/13/2022]
Abstract
The importance of Zn ions (Zn) in regulating development and functions of the immune system is well established. However, recent years have witnessed a surge in our knowledge of how immune cells choreograph Zn regulatory mechanisms to combat the persistence of pathogenic microbes. Myeloid and lymphoid populations manipulate intracellular and extracellular Zn metabolism via Zn binding proteins and transporters in response to immunological signals and infection. Rapid as well as delayed changes in readily exchangeable Zn, also known as free Zn and the Zn proteome are crucial in determining activation of immune cells, cytokine responses, signaling and nutritional immunity. Recent studies have unearthed distinctive Zn modulatory mechanisms employed by specialized immune cells and necessitate an understanding of the Zn handling behavior in immune responses to infection. The focus of this review, therefore, stems from novel revelations of Zn intoxication, sequestration and signaling roles deployed by different immune cells, with an emphasis on innate immunity, to challenge microbial parasitization and cope with pathogen insult.
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Affiliation(s)
| | - George S Deepe
- Division of Infectious Diseases, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA; Veterans Affairs Hospital, Cincinnati, OH 45220, USA.
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30
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Spraggins JM, Rizzo DG, Moore JL, Noto MJ, Skaar EP, Caprioli RM. Next-generation technologies for spatial proteomics: Integrating ultra-high speed MALDI-TOF and high mass resolution MALDI FTICR imaging mass spectrometry for protein analysis. Proteomics 2016; 16:1678-89. [PMID: 27060368 DOI: 10.1002/pmic.201600003] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/02/2016] [Accepted: 03/31/2016] [Indexed: 12/23/2022]
Abstract
MALDI imaging mass spectrometry is a powerful analytical tool enabling the visualization of biomolecules in tissue. However, there are unique challenges associated with protein imaging experiments including the need for higher spatial resolution capabilities, improved image acquisition rates, and better molecular specificity. Here we demonstrate the capabilities of ultra-high speed MALDI-TOF and high mass resolution MALDI FTICR IMS platforms as they relate to these challenges. High spatial resolution MALDI-TOF protein images of rat brain tissue and cystic fibrosis lung tissue were acquired at image acquisition rates >25 pixels/s. Structures as small as 50 μm were spatially resolved and proteins associated with host immune response were observed in cystic fibrosis lung tissue. Ultra-high speed MALDI-TOF enables unique applications including megapixel molecular imaging as demonstrated for lipid analysis of cystic fibrosis lung tissue. Additionally, imaging experiments using MALDI FTICR IMS were shown to produce data with high mass accuracy (<5 ppm) and resolving power (∼75 000 at m/z 5000) for proteins up to ∼20 kDa. Analysis of clear cell renal cell carcinoma using MALDI FTICR IMS identified specific proteins localized to healthy tissue regions, within the tumor, and also in areas of increased vascularization around the tumor.
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Affiliation(s)
- Jeffrey M Spraggins
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - David G Rizzo
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Jessica L Moore
- Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, USA
| | - Michael J Noto
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Eric P Skaar
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN, USA.,United States (U.S.) Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN, USA
| | - Richard M Caprioli
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, USA.,Mass Spectrometry Research Center, Vanderbilt University School of Medicine, Nashville, TN, USA.,Department of Chemistry, Vanderbilt University, Nashville, TN, USA.,Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA.,Departments of Pharmacology and Medicine, Vanderbilt University School of Medicine, Nashville, TN, USA
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Magon NJ, Turner R, Gearry RB, Hampton MB, Sly PD, Kettle AJ. Oxidation of calprotectin by hypochlorous acid prevents chelation of essential metal ions and allows bacterial growth: Relevance to infections in cystic fibrosis. Free Radic Biol Med 2015; 86:133-44. [PMID: 26006104 DOI: 10.1016/j.freeradbiomed.2015.05.022] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2015] [Revised: 05/14/2015] [Accepted: 05/15/2015] [Indexed: 11/16/2022]
Abstract
Calprotectin provides nutritional immunity by sequestering manganese and zinc ions. It is abundant in the lungs of patients with cystic fibrosis but fails to prevent their recurrent infections. Calprotectin is a major protein of neutrophils and composed of two monomers, S100A8 and S100A9. We show that the ability of calprotectin to limit growth of Staphylococcus aureus and Pseudomonas aeruginosa is exquisitely sensitive to oxidation by hypochlorous acid. The N-terminal cysteine residue on S100A9 was highly susceptible to oxidation which resulted in cross-linking of the protein monomers. The N-terminal methionine of S100A8 was also readily oxidized by hypochlorous acid, forming both the methionine sulfoxide and the unique product dehydromethionine. Isolated human neutrophils formed these modifications on calprotectin when their myeloperoxidase generated hypochlorous acid. Up to 90% of the N-terminal amine on S100A8 in bronchoalveolar lavage fluid from young children with cystic fibrosis was oxidized. Oxidized calprotectin was higher in children with cystic fibrosis compared to disease controls, and further elevated in those patients with infections. Our data suggest that oxidative stress associated with inflammation in cystic fibrosis will stop metal sequestration by calprotectin. Consequently, strategies aimed at blocking extracellular myeloperoxidase activity should enable calprotectin to provide nutritional immunity within the airways.
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Affiliation(s)
- Nicholas J Magon
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Rufus Turner
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Richard B Gearry
- Department of Medicine, University of Otago, Christchurch, New Zealand
| | - Mark B Hampton
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand
| | - Peter D Sly
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand; Department of Medicine, University of Otago, Christchurch, New Zealand
| | - Anthony J Kettle
- Centre for Free Radical Research, Department of Pathology, University of Otago, Christchurch, New Zealand.
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Nairz M, Schroll A, Demetz E, Tancevski I, Theurl I, Weiss G. 'Ride on the ferrous wheel'--the cycle of iron in macrophages in health and disease. Immunobiology 2014; 220:280-94. [PMID: 25240631 DOI: 10.1016/j.imbio.2014.09.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/20/2014] [Accepted: 09/05/2014] [Indexed: 12/16/2022]
Abstract
Iron homeostasis and macrophage biology are closely interconnected. On the one hand, iron exerts multiple effects on macrophage polarization and functionality. On the other hand, macrophages are central for mammalian iron homeostasis. The phagocytosis of senescent erythrocytes and their degradation by macrophages enable efficient recycling of iron and the maintenance of systemic iron balance. Macrophages express multiple molecules and proteins for the acquisition and utilization of iron and many of these pathways are affected by inflammatory signals. Of note, iron availability within macrophages has significant effects on immune effector functions and metabolic pathways within these cells. This review summarizes the physiological and pathophysiological aspects of macrophage iron metabolism and highlights its relevant consequences on immune function and in common diseases such as infection and atherosclerosis.
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Affiliation(s)
- Manfred Nairz
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria.
| | - Andrea Schroll
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Egon Demetz
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Ivan Tancevski
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Igor Theurl
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria.
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Bertrand RL. Lag phase-associated iron accumulation is likely a microbial counter-strategy to host iron sequestration: role of the ferric uptake regulator (fur). J Theor Biol 2014; 359:72-9. [PMID: 24929040 DOI: 10.1016/j.jtbi.2014.05.039] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 05/19/2014] [Accepted: 05/27/2014] [Indexed: 01/26/2023]
Abstract
Iron is an essential metal for almost all forms of life, but potentiates oxidative stress via Fenton catalysis. During microbial lag phase there is a rapid influx of iron with concomitant oxidative hypersensitivity. How and why iron accumulation occurs remains to be elucidated. Iron homeostasis in prokaryotes is mediated by the ferric uptake regulator (Fur), an iron-activated global regulator that controls intracellular iron levels by feedback inhibition with the metal. Herein it is postulated, based on the expression profiles of antioxidant enzymes within the Fur regulon as observed in wild type and Δfur mutants, that iron accumulation is mediated by a transitively low concentration of the Fur protein during lag phase. Vertebrate hosts sequester iron upon 'sensing' an infection in order to retard microbial proliferation through a process known as 'nutritional immunity'. It is herein argued that the purpose of iron accumulation is not principally a preparative step for the replicative phase, as suggested elsewhere, but an evolved behavior that counteracts host iron sequestration. This interpretation is supported by multiple clinical and animal studies that demonstrate that iron surplus in hosts advances progression and susceptibility to infection, and vice versa. Contextualizing iron accumulation as a counter-immune behavior adds impetus to the development of antibiotics targeting pathogenic modes of iron acquisition.
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Affiliation(s)
- Robert L Bertrand
- Department of Chemistry, University of Winnipeg, Winnipeg, MB, Canada R3B 2E9.
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Abstract
The intestinal epithelium is a single cell barrier separating a sterile mucosal tissue from a large microbial community dominated by obligate anaerobic bacteria, which inhabit the gut lumen. To maintain mucosal integrity, any breach in the epithelial barrier needs to be met with an inflammatory host response designed to repel microbial intruders from the tissue, protect the mucosal surface and repair injuries to the epithelium. In addition, inflammation induces mechanisms of nutritional immunity, which limit the availability of metals in the intestinal lumen, thereby imposing new selective forces on microbial growth. However, the inflammatory host response also has important side effects. A by-product of producing reactive oxygen and nitrogen species aimed at eradicating microbial intruders is the luminal generation of exogenous electron acceptors. The presence of these electron acceptors creates a new metabolic niche that is filled by facultative anaerobic bacteria. Here we review the changes in microbial nutrient utilization that accompany intestinal inflammation and the consequent changes in the composition of gut-associated microbial communities.
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Affiliation(s)
- Franziska Faber
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA
| | - Andreas J Bäumler
- Department of Medical Microbiology and Immunology, School of Medicine, University of California at Davis, One Shields Avenue, Davis, CA 95616, USA.
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Barel M, Charbit A. Francisella tularensis intracellular survival: to eat or to die. Microbes Infect 2013; 15:989-97. [PMID: 24513705 DOI: 10.1016/j.micinf.2013.09.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 09/23/2013] [Accepted: 09/23/2013] [Indexed: 12/15/2022]
Abstract
Francisella tularensis is a highly infectious facultative intracellular bacterium causing the zoonotic disease tularemia. Numerous attributes required for F. tularensis intracellular multiplication have been identified recently. However, the mechanisms by which the majority of them interfere with the infected host are still poorly understood. The following review summarizes our current knowledge on the different steps of Francisella intramacrophagic life cycle and expands on the importance of nutrient acquisition.
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