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Morimoto YV. Ion Signaling in Cell Motility and Development in Dictyostelium discoideum. Biomolecules 2024; 14:830. [PMID: 39062545 PMCID: PMC11274586 DOI: 10.3390/biom14070830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2024] [Revised: 07/08/2024] [Accepted: 07/09/2024] [Indexed: 07/28/2024] Open
Abstract
Cell-to-cell communication is fundamental to the organization and functionality of multicellular organisms. Intercellular signals orchestrate a variety of cellular responses, including gene expression and protein function changes, and contribute to the integrated functions of individual tissues. Dictyostelium discoideum is a model organism for cell-to-cell interactions mediated by chemical signals and multicellular formation mechanisms. Upon starvation, D. discoideum cells exhibit coordinated cell aggregation via cyclic adenosine 3',5'-monophosphate (cAMP) gradients and chemotaxis, which facilitates the unicellular-to-multicellular transition. During this process, the calcium signaling synchronizes with the cAMP signaling. The resulting multicellular body exhibits organized collective migration and ultimately forms a fruiting body. Various signaling molecules, such as ion signals, regulate the spatiotemporal differentiation patterns within multicellular bodies. Understanding cell-to-cell and ion signaling in Dictyostelium provides insight into general multicellular formation and differentiation processes. Exploring cell-to-cell and ion signaling enhances our understanding of the fundamental biological processes related to cell communication, coordination, and differentiation, with wide-ranging implications for developmental biology, evolutionary biology, biomedical research, and synthetic biology. In this review, I discuss the role of ion signaling in cell motility and development in D. discoideum.
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Affiliation(s)
- Yusuke V. Morimoto
- Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, 680-4 Kawazu, Iizuka 820-8502, Fukuoka, Japan;
- Japan Science and Technology Agency, PRESTO, 4-1-8 Honcho, Kawaguchi 332-0012, Saitama, Japan
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2
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Guallar-Garrido S, Soldati T. Exploring host-pathogen interactions in the Dictyostelium discoideum-Mycobacterium marinum infection model of tuberculosis. Dis Model Mech 2024; 17:dmm050698. [PMID: 39037280 DOI: 10.1242/dmm.050698] [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] [Indexed: 07/23/2024] Open
Abstract
Mycobacterium tuberculosis is a pathogenic mycobacterium that causes tuberculosis. Tuberculosis is a significant global health concern that poses numerous clinical challenges, particularly in terms of finding effective treatments for patients. Throughout evolution, host immune cells have developed cell-autonomous defence strategies to restrain and eliminate mycobacteria. Concurrently, mycobacteria have evolved an array of virulence factors to counteract these host defences, resulting in a dynamic interaction between host and pathogen. Here, we review recent findings, including those arising from the use of the amoeba Dictyostelium discoideum as a model to investigate key mycobacterial infection pathways. D. discoideum serves as a scalable and genetically tractable model for human phagocytes, providing valuable insights into the intricate mechanisms of host-pathogen interactions. We also highlight certain similarities between M. tuberculosis and Mycobacterium marinum, and the use of M. marinum to more safely investigate mycobacteria in D. discoideum.
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Affiliation(s)
- Sandra Guallar-Garrido
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
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3
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More KJ, Kaur H, Simpson AGB, Spiegel FW, Dacks JB. Contractile vacuoles: a rapidly expanding (and occasionally diminishing?) understanding. Eur J Protistol 2024; 94:126078. [PMID: 38688044 DOI: 10.1016/j.ejop.2024.126078] [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: 12/19/2023] [Revised: 03/18/2024] [Accepted: 03/20/2024] [Indexed: 05/02/2024]
Abstract
Osmoregulation is the homeostatic mechanism essential for the survival of organisms in hypoosmotic and hyperosmotic conditions. In freshwater or soil dwelling protists this is frequently achieved through the action of an osmoregulatory organelle, the contractile vacuole. This endomembrane organelle responds to the osmotic challenges and compensates by collecting and expelling the excess water to maintain the cellular osmolarity. As compared with other endomembrane organelles, this organelle is underappreciated and under-studied. Here we review the reported presence or absence of contractile vacuoles across eukaryotic diversity, as well as the observed variability in the structure, function, and molecular machinery of this organelle. Our findings highlight the challenges and opportunities for constructing cellular and evolutionary models for this intriguing organelle.
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Affiliation(s)
- Kiran J More
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Harpreet Kaur
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Alastair G B Simpson
- Centre for Comparative Genomics and Evolutionary Bioinformatics, Dalhousie University, Halifax, NS, Canada; Department of Biology, Dalhousie University, Halifax, NS, Canada
| | - Frederick W Spiegel
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Joel B Dacks
- Division of Infectious Diseases, Department of Medicine, and Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada; Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic; Centre for Life's Origins and Evolution, Department of Genetics, Evolution, & Environment, University College, London, United Kingdom.
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4
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Yu Y, Li YP, Ren K, Hao X, Fru EC, Rønn R, Rivera WL, Becker K, Feng R, Yang J, Rensing C. A brief history of metal recruitment in protozoan predation. Trends Microbiol 2024; 32:465-476. [PMID: 38103995 DOI: 10.1016/j.tim.2023.11.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Revised: 11/20/2023] [Accepted: 11/23/2023] [Indexed: 12/19/2023]
Abstract
Metals and metalloids are used as weapons for predatory feeding by unicellular eukaryotes on prokaryotes. This review emphasizes the role of metal(loid) bioavailability over the course of Earth's history, coupled with eukaryogenesis and the evolution of the mitochondrion to trace the emergence and use of the metal(loid) prey-killing phagosome as a feeding strategy. Members of the genera Acanthamoeba and Dictyostelium use metals such as zinc (Zn) and copper (Cu), and possibly metalloids, to kill their bacterial prey after phagocytosis. We provide a potential timeline on when these capacities first evolved and how they correlate with perceived changes in metal(loid) bioavailability through Earth's history. The origin of phagotrophic eukaryotes must have postdated the Great Oxidation Event (GOE) in agreement with redox-dependent modification of metal(loid) bioavailability for phagotrophic poisoning. However, this predatory mechanism is predicted to have evolved much later - closer to the origin of the multicellular metazoans and the evolutionary development of the immune systems.
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Affiliation(s)
- Yanshuang Yu
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Yuan-Ping Li
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Kexin Ren
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China
| | - Xiuli Hao
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, Huazhong Agricultural University, Wuhan 430070, China
| | - Ernest Chi Fru
- Centre for Geobiology and Geochemistry, School of Earth and Ocean Sciences, Cardiff University, CF10 3AT Cardiff, UK
| | - Regin Rønn
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Windell L Rivera
- Pathogen-Host-Environment Interactions Research Laboratory, Institute of Biology, College of Science, University of the Philippines Diliman, Quezon City 1101, Philippines
| | - Karsten Becker
- Friedrich Loeffler-Institute for Medical Microbiology, University Medicine Greifswald, D-17489 Greifswald, Germany
| | - Renwei Feng
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China
| | - Jun Yang
- Aquatic EcoHealth Group, Fujian Key Laboratory of Watershed Ecology, Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, China.
| | - Christopher Rensing
- Institute of Environmental Microbiology, College of Resources and Environment, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
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Lopez AE, Grigoryeva LS, Barajas A, Cianciotto NP. Legionella pneumophila Rhizoferrin Promotes Bacterial Biofilm Formation and Growth within Amoebae and Macrophages. Infect Immun 2023; 91:e0007223. [PMID: 37428036 PMCID: PMC10429650 DOI: 10.1128/iai.00072-23] [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: 02/15/2023] [Accepted: 06/20/2023] [Indexed: 07/11/2023] Open
Abstract
Previously, we showed that Legionella pneumophila secretes rhizoferrin, a polycarboxylate siderophore that promotes bacterial growth in iron-deplete media and the murine lung. Yet, past studies failed to identify a role for the rhizoferrin biosynthetic gene (lbtA) in L. pneumophila infection of host cells, suggesting the siderophore's importance was solely linked to extracellular survival. To test the possibility that rhizoferrin's relevance to intracellular infection was missed due to functional redundancy with the ferrous iron transport (FeoB) pathway, we characterized a new mutant lacking both lbtA and feoB. This mutant was highly impaired for growth on bacteriological media that were only modestly depleted of iron, confirming that rhizoferrin-mediated ferric iron uptake and FeoB-mediated ferrous iron uptake are critical for iron acquisition. The lbtA feoB mutant, but not its lbtA-containing complement, was also highly defective for biofilm formation on plastic surfaces, demonstrating a new role for the L. pneumophila siderophore in extracellular survival. Finally, the lbtA feoB mutant, but not its complement containing lbtA, proved to be greatly impaired for growth in Acanthamoeba castellanii, Vermamoeba vermiformis, and human U937 cell macrophages, revealing that rhizoferrin does promote intracellular infection by L. pneumophila. Moreover, the application of purified rhizoferrin triggered cytokine production from the U937 cells. Rhizoferrin-associated genes were fully conserved across the many sequenced strains of L. pneumophila examined but were variably present among strains from the other species of Legionella. Outside of Legionella, the closest match to the L. pneumophila rhizoferrin genes was in Aquicella siphonis, another facultative intracellular parasite of amoebae.
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Affiliation(s)
- Alberto E. Lopez
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Lubov S. Grigoryeva
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Armando Barajas
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
| | - Nicholas P. Cianciotto
- Department of Microbiology and Immunology, Northwestern University Medical School, Chicago, Illinois, USA
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Grechnikova M, Arbon D, Ženíšková K, Malych R, Mach J, Krejbichová L, Šimáčková A, Sutak R. Elucidation of iron homeostasis in Acanthamoeba castellanii. Int J Parasitol 2022; 52:497-508. [PMID: 35533729 DOI: 10.1016/j.ijpara.2022.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 03/21/2022] [Accepted: 03/27/2022] [Indexed: 11/25/2022]
Abstract
Acanthamoeba castellanii is a ubiquitously distributed amoeba that can be found in soil, dust, natural and tap water, air conditioners, hospitals, contact lenses and other environments. It is an amphizoic organism that can cause granulomatous amoebic encephalitis, an infrequent fatal disease of the central nervous system, and amoebic keratitis, a severe corneal infection that can lead to blindness. These diseases are extremely hard to treat; therefore, a more comprehensive understanding of this pathogen's metabolism is essential for revealing potential therapeutic targets. To propagate successfully in human tissues, the parasites must resist the iron depletion caused by nutritional immunity. The aim of our study is to elucidate the mechanisms underlying iron homeostasis in A. castellanii. Using a comparative whole-cell proteomic analysis of cells grown under different degrees of iron availability, we identified the primary proteins involved in Acanthamoeba iron acquisition. Our results suggest a two-step reductive mechanism of iron acquisition by a ferric reductase from the STEAP family and a divalent metal transporter from the NRAMP family. Both proteins are localized to the membranes of acidified digestive vacuoles where endocytosed medium and bacteria are trafficked. The expression levels of these proteins are significantly higher under iron-limited conditions, which allows Acanthamoeba to increase the efficiency of iron uptake despite the observed reduced pinocytosis rate. We propose that excessive iron gained while grown under iron-rich conditions is removed from the cytosol into the vacuoles by an iron transporter homologous to VIT/Ccc1 proteins. Additionally, we identified a novel protein that may participate in iron uptake regulation, the overexpression of which leads to increased iron acquisition.
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Affiliation(s)
- Maria Grechnikova
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Dominik Arbon
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Kateřina Ženíšková
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Ronald Malych
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Jan Mach
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Lucie Krejbichová
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Aneta Šimáčková
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic
| | - Robert Sutak
- Department of Parasitology, Charles University, Faculty of Science, BIOCEV, Průmyslová 595, 252 50 Vestec, Czech Republic.
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Peracino B, Monica V, Primo L, Bracco E, Bozzaro S. Iron metabolism in the social amoeba Dictyostelium discoideum: a role for Ferric Chelate Reductases. Eur J Cell Biol 2022; 101:151230. [DOI: 10.1016/j.ejcb.2022.151230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 04/07/2022] [Accepted: 04/25/2022] [Indexed: 11/17/2022] Open
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Amaro F, Martín-González A. Microbial warfare in the wild-the impact of protists on the evolution and virulence of bacterial pathogens. Int Microbiol 2021; 24:559-571. [PMID: 34365574 DOI: 10.1007/s10123-021-00192-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Revised: 06/03/2021] [Accepted: 06/28/2021] [Indexed: 01/01/2023]
Abstract
During the long history of co-evolution with protists, bacteria have evolved defense strategies to avoid grazing and survive phagocytosis. These mechanisms allow bacteria to exploit phagocytic cells as a protective niche in which to escape from environmental stress and even replicate. Importantly, these anti-grazing mechanisms can function as virulence factors when bacteria infect humans. Here, we discuss how protozoan predation exerts a selective pressure driving bacterial virulence and shaping their genomes, and how bacteria-protist interactions might contribute to the spread of antibiotic resistance as well. We provide examples to demonstrate that besides being voracious bacterial predators, protozoa can serve as melting pots where intracellular organisms exchange genetic information, or even "training grounds" where some pathogens become hypervirulent after passing through. In this special issue, we would like to emphasize the tremendous impact of bacteria-protist interactions on human health and the potential of amoebae as model systems to study biology and evolution of a variety of pathogens. Besides, a better understanding of bacteria-protist relationships will help us expand our current understanding of bacterial virulence and, likely, how pathogens emerge.
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Affiliation(s)
- Francisco Amaro
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University of Madrid, 28040, Madrid, Spain.
| | - Ana Martín-González
- Department of Genetics, Physiology and Microbiology, School of Biology, Complutense University of Madrid, 28040, Madrid, Spain
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Cinquetti R, Imperiali FG, Bozzaro S, Zanella D, Vacca F, Roseti C, Peracino B, Castagna M, Bossi E. Characterization of Transport Activity of SLC11 Transporters in Xenopus laevis Oocytes by Fluorophore Quenching. SLAS DISCOVERY 2021; 26:798-810. [PMID: 33825579 DOI: 10.1177/24725552211004123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Membrane proteins are involved in different physiological functions and are the target of pharmaceutical and abuse drugs. Xenopus laevis oocytes provide a powerful heterologous expression system for functional studies of these proteins. Typical experiments investigate transport using electrophysiology and radiolabeled uptake. A two-electrode voltage clamp is suitable only for electrogenic proteins, and uptake measurements require the existence of radiolabeled substrates and adequate laboratory facilities.Recently, Dictyostelium discoideum Nramp1 and NrampB were characterized using multidisciplinary approaches. NrampB showed no measurable electrogenic activity, and it was investigated in Xenopus oocytes by acquiring confocal images of the quenching of injected fluorophore calcein.This method is adequate to measure the variation in emitted fluorescence, and thus transporter activity indirectly, but requires long experimental procedures to collect statistically consistent data. Considering that optimal expression of heterologous proteins lasts for 48-72 h, a slow acquiring process requires the use of more than one batch of oocytes to complete the experiments. Here, a novel approach to measure substrate uptake is reported. Upon injection of a fluorophore, oocytes were incubated with the substrate and the transport activity measured, evaluating fluorescence quenching in a microplate reader. The technique permits the testing of tens of oocytes in different experimental conditions simultaneously, and thus the collection of significant statistical data for each batch, saving time and animals.The method was tested with different metal transporters (SLC11), DMT1, DdNramp1, and DdNrampB, and verified with the peptide transporter PepT1 (SLC15). Comparison with traditional methods (uptake, two-electrode voltage clamp) and with quenching images acquired by fluorescence microscopy confirmed its efficacy.
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Affiliation(s)
| | | | | | - Daniele Zanella
- University of Insubria, Varese, Lombardia, Italy.,The University of Alabama, Birmingham, AL, USA
| | - Francesca Vacca
- University of Insubria, Varese, Lombardia, Italy.,Italian Institute of Technology (IIT), Genova, Italy
| | | | | | | | - Elena Bossi
- University of Insubria, Varese, Lombardia, Italy
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Zn 2+ Intoxication of Mycobacterium marinum during Dictyostelium discoideum Infection Is Counteracted by Induction of the Pathogen Zn 2+ Exporter CtpC. mBio 2021; 12:mBio.01313-20. [PMID: 33531393 PMCID: PMC7858047 DOI: 10.1128/mbio.01313-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Microelements are essential for the function of the innate immune system. A deficiency in zinc or copper results in an increased susceptibility to bacterial infections. Macrophages use diverse strategies to restrict intracellular pathogens, including either depriving the bacteria of (micro)nutrients such as transition metals or intoxicating them via metal accumulation. Little is known about the chemical warfare between Mycobacterium marinum, a close relative of Mycobacterium tuberculosis (Mtb), and its hosts. We use the professional phagocyte Dictyostelium discoideum to investigate the role of Zn2+ during M. marinum infection. We show that M. marinum senses toxic levels of Zn2+ and responds by upregulating one of its isoforms of the Zn2+ efflux transporter CtpC. Deletion of ctpC (MMAR_1271) leads to growth inhibition in broth supplemented with Zn2+ as well as reduced intracellular growth. Both phenotypes were fully rescued by constitutive ectopic expression of the Mtb CtpC orthologue demonstrating that MMAR_1271 is the functional CtpC Zn2+ efflux transporter in M. marinum. Infection leads to the accumulation of Zn2+ inside the Mycobacterium-containing vacuole (MCV), achieved by the induction and recruitment of the D. discoideum Zn2+ efflux pumps ZntA and ZntB. In cells lacking ZntA, there is further attenuation of M. marinum growth, presumably due to a compensatory efflux of Zn2+ into the MCV, carried out by ZntB, the main Zn2+ transporter in endosomes and phagosomes. Counterintuitively, bacterial growth is also impaired in zntB KO cells, in which MCVs appear to accumulate less Zn2+ than in wild-type cells, suggesting restriction by other Zn2+-mediated mechanisms. Absence of CtpC further epistatically attenuates the intracellular proliferation of M. marinum in zntA and zntB KO cells, confirming that mycobacteria face noxious levels of Zn2+.
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Olmos J, Pignataro MF, Benítez dos Santos AB, Bringas M, Klinke S, Kamenetzky L, Velazquez F, Santos J. A Highly Conserved Iron-Sulfur Cluster Assembly Machinery between Humans and Amoeba Dictyostelium discoideum: The Characterization of Frataxin. Int J Mol Sci 2020; 21:E6821. [PMID: 32957566 PMCID: PMC7554988 DOI: 10.3390/ijms21186821] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 09/05/2020] [Accepted: 09/14/2020] [Indexed: 12/17/2022] Open
Abstract
Several biological activities depend on iron-sulfur clusters ([Fe-S]). Even though they are well-known in several organisms their function and metabolic pathway were poorly understood in the majority of the organisms. We propose to use the amoeba Dictyostelium discoideum, as a biological model to study the biosynthesis of [Fe-S] at the molecular, cellular and organism levels. First, we have explored the D. discoideum genome looking for genes corresponding to the subunits that constitute the molecular machinery for Fe-S cluster assembly and, based on the structure of the mammalian supercomplex and amino acid conservation profiles, we inferred the full functionality of the amoeba machinery. After that, we expressed the recombinant mature form of D. discoideum frataxin protein (DdFXN), the kinetic activator of this pathway. We characterized the protein and its conformational stability. DdFXN is monomeric and compact. The analysis of the secondary structure content, calculated using the far-UV CD spectra, was compatible with the data expected for the FXN fold, and near-UV CD spectra were compatible with the data corresponding to a folded protein. In addition, Tryptophan fluorescence indicated that the emission occurs from an apolar environment. However, the conformation of DdFXN is significantly less stable than that of the human FXN, (4.0 vs. 9.0 kcal mol-1, respectively). Based on a sequence analysis and structural models of DdFXN, we investigated key residues involved in the interaction of DdFXN with the supercomplex and the effect of point mutations on the energetics of the DdFXN tertiary structure. More than 10 residues involved in Friedreich's Ataxia are conserved between the human and DdFXN forms, and a good correlation between mutational effect on the energetics of both proteins were found, suggesting the existence of similar sequence/function/stability relationships. Finally, we integrated this information in an evolutionary context which highlights particular variation patterns between amoeba and humans that may reflect a functional importance of specific protein positions. Moreover, the complete pathway obtained forms a piece of evidence in favor of the hypothesis of a shared and highly conserved [Fe-S] assembly machinery between Human and D. discoideum.
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Affiliation(s)
- Justo Olmos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - María Florencia Pignataro
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - Ana Belén Benítez dos Santos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
| | - Mauro Bringas
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Instituto de Química Física de los Materiales, Medio Ambiente y Energía (INQUIMAE CONICET), Buenos Aires C1428EGA, Argentina;
| | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA-CONICET, and Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Av. Patricias Argentinas 435, Buenos Aires C1405BWE, Argentina;
| | - Laura Kamenetzky
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- IMPaM, CONICET, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
| | - Francisco Velazquez
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN)—(UBA/CONICET), Buenos Aires C1428EGA, Argentina
| | - Javier Santos
- Instituto de Biociencias, Biotecnología y Biología Traslacional (iB3), Departamento de Fisiología y Biología Molecular y Celular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina; (J.O.); (M.F.P.); (A.B.B.d.S.); (L.K.)
- Consejo Nacional de Investigaciones Científicas y Técnicas, Rivadavia 1917, Buenos Aires C1033AAJ, Argentina
- Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires. Intendente Güiraldes 2160, Ciudad Universitaria, Buenos Aires C1428EGA, Argentina
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Singh R, Ranaivoarisoa TO, Gupta D, Bai W, Bose A. Genetic Redundancy in Iron and Manganese Transport in the Metabolically Versatile Bacterium Rhodopseudomonas palustris TIE-1. Appl Environ Microbiol 2020; 86:e01057-20. [PMID: 32503905 PMCID: PMC7414945 DOI: 10.1128/aem.01057-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 05/31/2020] [Indexed: 12/24/2022] Open
Abstract
The purple nonsulfur bacterium Rhodopseudomonas palustris TIE-1 can produce useful biochemicals such as bioplastics and biobutanol. Production of such biochemicals requires intracellular electron availability, which is governed by the availability and the transport of essential metals such as iron (Fe). Because of the distinct chemical properties of ferrous [Fe(II)] and ferric iron [Fe(III)], different systems are required for their transport and storage in bacteria. Although Fe(III) transport systems are well characterized, we know much less about Fe(II) transport systems except for the FeoAB system. Iron transporters can also import manganese (Mn). We studied Fe and Mn transport by five putative Fe transporters in TIE-1 under metal-replete, metal-depleted, oxic, and anoxic conditions. We observed that by overexpressing feoAB, efeU, and nramp1AB, the intracellular concentrations of Fe and Mn can be enhanced in TIE-1 under oxic and anoxic conditions, respectively. The deletion of a single gene/operon does not attenuate Fe or Mn uptake in TIE-1 regardless of the growth conditions used. This indicates that genetically dissimilar yet functionally redundant Fe transporters in TIE-1 can complement each other. Relative gene expression analysis shows that feoAB and efeU are expressed during Fe and Mn depletion under both oxic and anoxic conditions. The promoters of these transporter genes contain a combination of Fur and Fnr boxes, suggesting that their expression is regulated by both Fe and oxygen availability. The findings from this study will help us modulate intracellular Fe and Mn concentrations, ultimately improving TIE-1's ability to produce desirable biomolecules.IMPORTANCERhodopseudomonas palustris TIE-1 is a metabolically versatile bacterium that can use various electron donors, including Fe(II) and poised electrodes, for photoautotrophic growth. TIE-1 can produce useful biomolecules, such as biofuels and bioplastics, under various growth conditions. Production of such reduced biomolecules is controlled by intracellular electron availability, which, in turn, is mediated by various iron-containing proteins in the cell. Several putative Fe transporters exist in TIE-1's genome. Some of these transporters can also transport Mn, part of several important cellular enzymes. Therefore, understanding the ability to transport and respond to various levels of Fe and Mn under different conditions is important to improve TIE-1's ability to produce useful biomolecules. Our data suggest that by overexpressing Fe transporter genes via plasmid-based expression, we can increase the import of Fe and Mn in TIE-1. Future work will leverage these data to improve TIE-1 as an attractive microbial chassis and future biotechnological workhorse.
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Affiliation(s)
- Rajesh Singh
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | | | - Dinesh Gupta
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Wei Bai
- Department of Energy, Environmental and Chemical Engineering, Washington University in St. Louis, St. Louis, Missouri, USA
| | - Arpita Bose
- Department of Biology, Washington University in St. Louis, St. Louis, Missouri, USA
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Paraburkholderia Symbionts Display Variable Infection Patterns That Are Not Predictive of Amoeba Host Outcomes. Genes (Basel) 2020; 11:genes11060674. [PMID: 32575747 PMCID: PMC7349545 DOI: 10.3390/genes11060674] [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: 05/14/2020] [Revised: 06/07/2020] [Accepted: 06/18/2020] [Indexed: 12/17/2022] Open
Abstract
Symbiotic interactions exist within a parasitism to mutualism continuum that is influenced, among others, by genes and context. Dynamics of intracellular invasion, replication, and prevalence may underscore both host survivability and symbiont stability. More infectious symbionts might exert higher corresponding costs to hosts, which could ultimately disadvantage both partners. Here, we quantify infection patterns of diverse Paraburkholderia symbiont genotypes in their amoeba host Dictyostelium discoideum and probe the relationship between these patterns and host outcomes. We exposed D. discoideum to thirteen strains of Paraburkholderia each belonging to one of the three symbiont species found to naturally infect D. discoideum: Paraburkholderia agricolaris, Paraburkholderia hayleyella, and Paraburkholderia bonniea. We quantified the infection prevalence and intracellular density of fluorescently labeled symbionts along with the final host population size using flow cytometry and confocal microscopy. We find that infection phenotypes vary across symbiont strains. Symbionts belonging to the same species generally display similar infection patterns but are interestingly distinct when it comes to host outcomes. This results in final infection loads that do not strongly correlate to final host outcomes, suggesting other genetic factors that are not a direct cause or consequence of symbiont abundance impact host fitness.
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14
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Knobloch P, Koliwer-Brandl H, Arnold FM, Hanna N, Gonda I, Adenau S, Personnic N, Barisch C, Seeger MA, Soldati T, Hilbi H. Mycobacterium marinum produces distinct mycobactin and carboxymycobactin siderophores to promote growth in broth and phagocytes. Cell Microbiol 2020; 22:e13163. [PMID: 31945239 DOI: 10.1111/cmi.13163] [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: 07/26/2019] [Accepted: 12/22/2019] [Indexed: 02/06/2023]
Abstract
Mycobacterium marinum is a model organism for pathogenic Mycobacterium species, including Mycobacterium tuberculosis, the causative agent of tuberculosis. These pathogens enter phagocytes and replicate within the Mycobacterium-containing vacuole, possibly followed by vacuole exit and growth in the host cell cytosol. Mycobacteria release siderophores called mycobactins to scavenge iron, an essential yet poorly soluble and available micronutrient. To investigate the role of M. marinum mycobactins, we purified by organic solvent extraction and identified by mass spectrometry the lipid-bound mycobactin (MBT) and the water-soluble variant carboxymycobactin (cMBT). Moreover, we generated by specialised phage transduction a defined M. marinum ΔmbtB deletion mutant predicted to be defective for mycobactin production. The M. marinum ΔmbtB mutant strain showed a severe growth defect in broth and phagocytes, which was partially complemented by supplying the mbtB gene on a plasmid. Furthermore, purified Fe-MBT or Fe-cMBT improved the growth of wild type as well as ΔmbtB mutant bacteria on minimal plates, but only Fe-cMBT promoted the growth of wild-type M. marinum during phagocyte infection. Finally, the intracellular growth of M. marinum ΔmbtB in Acanthamoeba castellanii amoebae was restored by coinfection with wild-type bacteria. Our study identifies and characterises the M. marinum MBT and cMBT siderophores and reveals the requirement of mycobactins for extra- and intracellular growth of the pathogen.
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Affiliation(s)
- Paulina Knobloch
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | | | - Fabian M Arnold
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Nabil Hanna
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Imre Gonda
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Sophia Adenau
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Nicolas Personnic
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Caroline Barisch
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Markus A Seeger
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Sciences, University of Geneva, Geneva, Switzerland
| | - Hubert Hilbi
- Institute of Medical Microbiology, University of Zürich, Zürich, Switzerland
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15
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Type II Secretion Promotes Bacterial Growth within the Legionella-Containing Vacuole in Infected Amoebae. Infect Immun 2019; 87:IAI.00374-19. [PMID: 31405960 DOI: 10.1128/iai.00374-19] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 08/08/2019] [Indexed: 12/30/2022] Open
Abstract
It was previously determined that the type II secretion system (T2SS) promotes the ability of Legionella pneumophila to grow in coculture with amoebae. Here, we discerned the stage of intracellular infection that is potentiated by comparing the wild-type and T2SS mutant legionellae for their capacity to parasitize Acanthamoeba castellanii Whereas the mutant behaved normally for entry into the host cells and subsequent evasion of degradative lysosomes, it was impaired in the ability to replicate, with that defect being first evident at approximately 9 h postentry. The replication defect was initially documented in three ways: by determining the numbers of CFU recovered from the lysates of the infected monolayers, by monitoring the levels of fluorescence associated with amoebal monolayers infected with green fluorescent protein (GFP)-expressing bacteria, and by utilizing flow cytometry to quantitate the amounts of GFP-expressing bacteria in individual amoebae. By employing confocal microscopy and newer imaging techniques, we further determined the progression in volume and shape of the bacterial vacuoles and found that the T2SS mutant grows at a decreased rate and does not attain maximally sized phagosomes. Overall, the entire infection cycle (i.e., entry to egress) was considerably slower for the T2SS mutant than it was for the wild-type strain, and the mutant's defect was maintained over multiple rounds of infection. Thus, the T2SS is absolutely required for L. pneumophila to grow to larger numbers in its intravacuolar niche within amoebae. Combining these results with those of our recent analysis of macrophage infection, T2SS is clearly a major component of L. pneumophila intracellular infection.
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Molecular identification and expression analysis of natural resistance-associated macrophage protein (Nramp) gene from yellow catfish Pelteobagrus fulvidraco (Siluriformes: Bagridae). Int J Biol Macromol 2019; 141:345-350. [PMID: 31491517 DOI: 10.1016/j.ijbiomac.2019.09.008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 08/05/2019] [Accepted: 09/03/2019] [Indexed: 12/23/2022]
Abstract
Natural resistance associated macrophage protein genes (Nramp) is one of the important candidate genes responsible for regulating immune response against pathogen infection. The aim of the present was to quantify expression of Nramp gene in response to pathogen infection. Here, a Nramp was identified and molecularly characterized from Pelteobagrus fulvidraco (PfNramp). The obtained 3134 bp cDNA fragment of PfNramp comprised a 5'-untranslated region (UTR) of 81 bp, a 3'-UTR of 1403 bp and an open reading frame (ORF) of 1650 bp, encoding a polypeptide of 549 amino acids that contained a typical structural features of Nramp domain (Pfam01566). BLAST analysis exhibited that PfNramp shared sequence similarity to other organisms, in particular to Ictalurus furcatus (92%), Danio rerio (82%), and Homo sapiens (77%). Phylogenetic analysis revealed that PfNramp is close to Teleostei. Real-time quantitative reverse transcription-PCR (qRT-PCR) analysis showed that PfNramp was expressed in all examined tissues, with the highest abundance in liver. The mRNA expression of PfNramp was remarkably increased at different time points after lipopolysaccharide (LPS), and polyriboinosinic polyribocytidylic acid (poly I:C) challenge. These results suggest that PfNramp is an inducible protein in the innate immune reactions of P. fulvidraco and probably in other fish species.
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Bozzaro S, Buracco S, Peracino B, Eichinger L. Dictyostelium Host Response to Legionella Infection: Strategies and Assays. Methods Mol Biol 2019; 1921:347-370. [PMID: 30694504 DOI: 10.1007/978-1-4939-9048-1_23] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The professional phagocyte Dictyostelium discoideum is a well-established model organism to study host-pathogen interactions. Dictyostelium amoebae grow as separate, independent cells; they divide by binary fission and take up bacteria and yeast via phagocytosis. In the year 2000, D. discoideum was described by two groups as a novel system for genetic analysis of host-pathogen interactions for the intracellular pathogen Legionella pneumophila. Since then additional microbial pathogens that can be studied in D. discoideum have been reported. The organism has various advantages for the dissection of the complex cross-talk between a host and a pathogen. A fully sequenced and well-curated genome is available, there are excellent molecular genetic tools on the market, and the generation of targeted multiple gene knock-outs as well as the realization of untargeted genetic screens is generally straightforward. Dictyostelium also offers easy cultivation, and the cells are suitable for cell biological studies, which in combination with in vivo expression of fluorescence-tagged proteins allows the investigation of the dynamics of bacterial uptake and infection. Furthermore, a large mutant collection is available at the Dictyostelium stock center, favoring the identification of host resistance or susceptibility genes. Here, we briefly describe strategies to identify host cell factors important during an infection, followed by protocols for cell culture and storage, uptake and infection, and confocal microscopy of infected cells.
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Affiliation(s)
- Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Italy.
| | - Simona Buracco
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Italy
| | - Barbara Peracino
- Department of Clinical and Biological Sciences, University of Turin, Orbassano, Italy
| | - Ludwig Eichinger
- Center for Biochemistry, Medical Faculty, University of Cologne, Cologne, Germany.
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18
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Natural Resistance Associated Macrophage Protein Is Involved in Immune Response of Blunt Snout Bream, Megalobrama amblycephala. Cells 2018; 7:cells7040027. [PMID: 29596379 PMCID: PMC5946104 DOI: 10.3390/cells7040027] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 03/07/2018] [Accepted: 03/24/2018] [Indexed: 01/01/2023] Open
Abstract
The natural resistance-associated macrophage protein gene (Nramp), has been identified as one of the significant candidate genes responsible for modulating vertebrate natural resistance to intracellular pathogens. Here, we identified and characterized a new Nramp family member, named as maNramp, in the blunt snout bream. The full-length cDNA of maNramp consists of a 153 bp 5′UTR, a 1635 bp open reading frame encoding a protein with 544 amino acids, and a 1359 bp 3′UTR. The deduced protein (maNRAMP) possesses the typical structural features of NRAMP protein family, including 12 transmembrane domains, three N-linked glycosylation sites, and a conserved transport motif. Phylogenetic analysis revealed that maNRAMP shares the significant sequence consistency with other teleosts, and shows the higher sequence similarity to mammalian Nramp2 than Nramp1. It was found that maNramp expressed ubiquitously in all normal tissues tested, with the highest abundance in the spleen, followed by the head kidney and intestine, and less abundance in the muscle, gill, and kidney. After lipopolysaccharide (LPS) stimulation, the mRNA level of maNramp was rapidly up-regulated, which reached a peak level at 6 h. Altogether, these results indicated that maNramp might be related to fish innate immunity and similar to mammalian Nramp1 in function.
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19
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Zondervan NA, van Dam JCJ, Schaap PJ, Martins Dos Santos VAP, Suarez-Diez M. Regulation of Three Virulence Strategies of Mycobacterium tuberculosis: A Success Story. Int J Mol Sci 2018; 19:E347. [PMID: 29364195 PMCID: PMC5855569 DOI: 10.3390/ijms19020347] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2017] [Revised: 01/19/2018] [Accepted: 01/21/2018] [Indexed: 12/28/2022] Open
Abstract
Tuberculosis remains one of the deadliest diseases. Emergence of drug-resistant and multidrug-resistant M. tuberculosis strains makes treating tuberculosis increasingly challenging. In order to develop novel intervention strategies, detailed understanding of the molecular mechanisms behind the success of this pathogen is required. Here, we review recent literature to provide a systems level overview of the molecular and cellular components involved in divalent metal homeostasis and their role in regulating the three main virulence strategies of M. tuberculosis: immune modulation, dormancy and phagosomal rupture. We provide a visual and modular overview of these components and their regulation. Our analysis identified a single regulatory cascade for these three virulence strategies that respond to limited availability of divalent metals in the phagosome.
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Affiliation(s)
- Niels A Zondervan
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Jesse C J van Dam
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Peter J Schaap
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
| | - Vitor A P Martins Dos Santos
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
- LifeGlimmer GmbH, Markelstrasse 38, 12163 Berlin, Germany.
| | - Maria Suarez-Diez
- Laboratory of Systems and Synthetic Biology, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands.
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20
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Buracco S, Peracino B, Andreini C, Bracco E, Bozzaro S. Differential Effects of Iron, Zinc, and Copper on Dictyostelium discoideum Cell Growth and Resistance to Legionella pneumophila. Front Cell Infect Microbiol 2018; 7:536. [PMID: 29379774 PMCID: PMC5770829 DOI: 10.3389/fcimb.2017.00536] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Accepted: 12/26/2017] [Indexed: 12/29/2022] Open
Abstract
Iron, zinc, and copper play fundamental roles in eucaryotes and procaryotes, and their bioavailability regulates host-pathogen interactions. For intracellular pathogens, the source of metals is the cytoplasm of the host, which in turn manipulates intracellular metal traffic following pathogen recognition. It is established that iron is withheld from the pathogen-containing vacuole, whereas for copper and zinc the evidence is unclear. Most infection studies in mammals have concentrated on effects of metal deficiency/overloading at organismal level. Thus, zinc deficiency or supplementation correlate with high risk of respiratory tract infection or recovery from severe infection, respectively. Iron, zinc, and copper deficiency or overload affects lymphocyte proliferation/maturation, and thus the adaptive immune response. Whether they regulate innate immunity at macrophage level is open, except for iron. The early identification in a mouse mutant susceptible to mycobacterial infection of the iron transporter Nramp1 allowed dissecting Nramp1 role in phagocytes, from the social amoeba Dictyostelium to macrophages. Nramp1 regulates iron efflux from the phagosomes, thus starving pathogenic bacteria for iron. Similar studies for zinc or copper are scant, due to the large number of copper and zinc transporters. In Dictyostelium, zinc and copper transporters include 11 and 6 members, respectively. To assess the role of zinc or copper in Dictyostelium, cells were grown under conditions of metal depletion or excess and tested for resistance to Legionella pneumophila infection. Iron shortage or overload inhibited Dictyostelium cell growth within few generations. Surprisingly, zinc or copper depletion failed to affect growth. Zinc or copper overloading inhibited cell growth at, respectively, 50- or 500-fold the physiological concentration, suggesting very efficient control of their homeostasis, as confirmed by Inductively Coupled Plasma Mass Spectrometry quantification of cellular metals. Legionella infection was inhibited or enhanced in cells grown under iron shortage or overload, respectively, confirming a major role for iron in controlling resistance to pathogens. In contrast, zinc and copper depletion or excess during growth did not affect Legionella infection. Using Zinpyr-1 as fluorescent sensor, we show that zinc accumulates in endo-lysosomal vesicles, including phagosomes, and the contractile vacuole. Furthermore, we provide evidence for permeabilization of the Legionella-containing vacuole during bacterial proliferation.
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Affiliation(s)
- Simona Buracco
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - Barbara Peracino
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
| | - Claudia Andreini
- Magnetic Resonance Center (CERM), University of Florence, Florence, Italy
| | - Enrico Bracco
- Department of Oncology, University of Torino, Turin, Italy
| | - Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Torino, Turin, Italy
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21
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Dunn JD, Bosmani C, Barisch C, Raykov L, Lefrançois LH, Cardenal-Muñoz E, López-Jiménez AT, Soldati T. Eat Prey, Live: Dictyostelium discoideum As a Model for Cell-Autonomous Defenses. Front Immunol 2018; 8:1906. [PMID: 29354124 PMCID: PMC5758549 DOI: 10.3389/fimmu.2017.01906] [Citation(s) in RCA: 89] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 12/13/2017] [Indexed: 12/11/2022] Open
Abstract
The soil-dwelling social amoeba Dictyostelium discoideum feeds on bacteria. Each meal is a potential infection because some bacteria have evolved mechanisms to resist predation. To survive such a hostile environment, D. discoideum has in turn evolved efficient antimicrobial responses that are intertwined with phagocytosis and autophagy, its nutrient acquisition pathways. The core machinery and antimicrobial functions of these pathways are conserved in the mononuclear phagocytes of mammals, which mediate the initial, innate-immune response to infection. In this review, we discuss the advantages and relevance of D. discoideum as a model phagocyte to study cell-autonomous defenses. We cover the antimicrobial functions of phagocytosis and autophagy and describe the processes that create a microbicidal phagosome: acidification and delivery of lytic enzymes, generation of reactive oxygen species, and the regulation of Zn2+, Cu2+, and Fe2+ availability. High concentrations of metals poison microbes while metal sequestration inhibits their metabolic activity. We also describe microbial interference with these defenses and highlight observations made first in D. discoideum. Finally, we discuss galectins, TNF receptor-associated factors, tripartite motif-containing proteins, and signal transducers and activators of transcription, microbial restriction factors initially characterized in mammalian phagocytes that have either homologs or functional analogs in D. discoideum.
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Affiliation(s)
- Joe Dan Dunn
- Faculty of Sciences, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Cristina Bosmani
- Faculty of Sciences, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Caroline Barisch
- Faculty of Sciences, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Lyudmil Raykov
- Faculty of Sciences, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Louise H Lefrançois
- Faculty of Sciences, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | - Elena Cardenal-Muñoz
- Faculty of Sciences, Department of Biochemistry, University of Geneva, Geneva, Switzerland
| | | | - Thierry Soldati
- Faculty of Sciences, Department of Biochemistry, University of Geneva, Geneva, Switzerland
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22
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Barisch C, Kalinina V, Lefrançois LH, Appiah J, López-Jiménez AT, Soldati T. Localization of all four ZnT zinc transporters in Dictyostelium and impact of ZntA and B knockout on bacteria killing. J Cell Sci 2018; 131:jcs.222000. [DOI: 10.1242/jcs.222000] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Accepted: 10/17/2018] [Indexed: 01/26/2023] Open
Abstract
Professional phagocytes have developed an extensive repertoire of autonomous immunity strategies to ensure killing of bacteria. Besides phagosome acidification and the generation of reactive oxygen species, deprivation of nutrients and the lumenal accumulation of toxic metals are essential to kill ingested bacteria or inhibit growth of intracellular pathogens. We use the soil amoeba Dictyostelium discoideum, a professional phagocyte that digests bacteria for nutritional purposes, to decipher the role of zinc poisoning during phagocytosis of non-pathogenic bacteria and visualize the temporal and spatial dynamics of compartmentalized, free zinc using fluorescent probes. Immediately after particle uptake, zinc is delivered to phagosomes by fusion with “zincosomes” of endosomal origin, but also by the action of one or more zinc transporters. We localize the four Dictyostelium ZnT transporters to endosomes, the contractile vacuole and the Golgi apparatus, and study the impact of znt knockouts on zinc homeostasis. Finally, we show that zinc is delivered into the lumen of Mycobacterium smegmatis-containing vacuoles, and that Escherichia coli deficient in the zinc efflux P1B-type ATPase ZntA is killed faster than wild type bacteria.
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Affiliation(s)
- Caroline Barisch
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
| | - Vera Kalinina
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
- Present address: Institute of Cytology, Russian Academy of Sciences, Tikhoretsky ave. 4, 194064 St. Petersburg, Russia
| | - Louise H. Lefrançois
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
| | - Joddy Appiah
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
| | - Ana T. López-Jiménez
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
| | - Thierry Soldati
- Department of Biochemistry, Faculty of Science, University of Geneva, 30 quai Ernest-Ansermet, Science II, 1211 Geneva-4, Switzerland
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23
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Abstract
Specialized adaptations for killing microbes are synonymous with phagocytic cells including macrophages, monocytes, inflammatory neutrophils, and eosinophils. Recent genome sequencing of extant species, however, reveals that analogous antimicrobial machineries exist in certain non-immune cells and also within species that ostensibly lack a well-defined immune system. Here we probe the evolutionary record for clues about the ancient and diverse phylogenetic origins of macrophage killing mechanisms and how some of their properties are shared with cells outside the traditional bounds of immunity in higher vertebrates such as mammals.
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24
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Brenz Y, Ohnezeit D, Winther-Larsen HC, Hagedorn M. Nramp1 and NrampB Contribute to Resistance against Francisella in Dictyostelium. Front Cell Infect Microbiol 2017; 7:282. [PMID: 28680861 PMCID: PMC5478718 DOI: 10.3389/fcimb.2017.00282] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 06/09/2017] [Indexed: 12/16/2022] Open
Abstract
The Francisella genus comprises highly pathogenic bacteria that can cause fatal disease in their vertebrate and invertebrate hosts including humans. In general, Francisella growth depends on iron availability, hence, iron homeostasis must be tightly regulated during Francisella infection. We used the system of the professional phagocyte Dictyostelium and the fish pathogen F. noatunensis subsp. noatunensis (F.n.n.) to investigate the role of the host cell iron transporters Nramp (natural resistance associated macrophage proteins) during Francisella infection. Like its mammalian ortholog, Dictyostelium Nramp1 transports iron from the phagosome into the cytosol, whereas the paralog NrampB is located on the contractile vacuole and controls, together with Nramp1, the cellular iron homeostasis. In Dictyostelium, Nramp1 localized to the F.n.n.-phagosome but disappeared from the compartment dependent on the presence of IglC, an established Francisella virulence factor. In the absence of Nramp transporters the bacteria translocated more efficiently from the phagosome into the host cell cytosol, its replicative niche. Increased escape rates coincided with increased proteolytic activity in bead-containing phagosomes indicating a role of the Nramp transporters for phagosomal maturation. In the nramp mutants, a higher bacterial load was observed in the replicative phase compared to wild-type host cells. Upon bacterial access to the cytosol of wt cells, mRNA levels of bacterial iron uptake factors were transiently upregulated. Decreased iron levels in the nramp mutants were compensated by a prolonged upregulation of the iron scavenging system. These results show that Nramps contribute to host cell immunity against Francisella infection by influencing the translocation efficiency from the phagosome to the cytosol but not by restricting access to nutritional iron in the cytosol.
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Affiliation(s)
- Yannick Brenz
- Department of Parasitology, Bernhard Nocht Institute for Tropical MedicineHamburg, Germany
| | - Denise Ohnezeit
- Institute for Medical Microbiology, Hygiene and Virology, University Medical Center Hamburg-EppendorfHamburg, Germany
| | - Hanne C Winther-Larsen
- Centre for Integrative Microbial Evolution and Department of Pharmaceutical Biosciences, University of OsloOslo, Norway
| | - Monica Hagedorn
- Department of Life Sciences and Chemistry, Jacobs UniversityBremen, Germany
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Developmental Control of NRAMP1 (SLC11A1) Expression in Professional Phagocytes. BIOLOGY 2017; 6:biology6020028. [PMID: 28467369 PMCID: PMC5485475 DOI: 10.3390/biology6020028] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/25/2017] [Accepted: 04/25/2017] [Indexed: 12/11/2022]
Abstract
NRAMP1 (SLC11A1) is a professional phagocyte membrane importer of divalent metals that contributes to iron recycling at homeostasis and to nutritional immunity against infection. Analyses of data generated by several consortia and additional studies were integrated to hypothesize mechanisms restricting NRAMP1 expression to mature phagocytes. Results from various epigenetic and transcriptomic approaches were collected for mesodermal and hematopoietic cell types and compiled for combined analysis with results of genetic studies associating single nucleotide polymorphisms (SNPs) with variations in NRAMP1 expression (eQTLs). Analyses establish that NRAMP1 is part of an autonomous topologically associated domain delimited by ubiquitous CCCTC-binding factor (CTCF) sites. NRAMP1 locus contains five regulatory regions: a predicted super-enhancer (S-E) key to phagocyte-specific expression; the proximal promoter; two intronic areas, including 3' inhibitory elements that restrict expression during development; and a block of upstream sites possibly extending the S-E domain. Also the downstream region adjacent to the 3' CTCF locus boundary may regulate expression during hematopoiesis. Mobilization of the locus 14 predicted transcriptional regulatory elements occurs in three steps, beginning with hematopoiesis; at the onset of myelopoiesis and through myelo-monocytic differentiation. Basal expression level in mature phagocytes is further influenced by genetic variation, tissue environment, and in response to infections that induce various epigenetic memories depending on microorganism nature. Constitutively associated transcription factors (TFs) include CCAAT enhancer binding protein beta (C/EBPb), purine rich DNA binding protein (PU.1), early growth response 2 (EGR2) and signal transducer and activator of transcription 1 (STAT1) while hypoxia-inducible factors (HIFs) and interferon regulatory factor 1 (IRF1) may stimulate iron acquisition in pro-inflammatory conditions. Mouse orthologous locus is generally conserved; chromatin patterns typify a de novo myelo-monocytic gene whose expression is tightly controlled by TFs Pu.1, C/ebps and Irf8; Irf3 and nuclear factor NF-kappa-B p 65 subunit (RelA) regulate expression in inflammatory conditions. Functional differences in the determinants identified at these orthologous loci imply that species-specific mechanisms control gene expression.
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Chandrangsu P, Rensing C, Helmann JD. Metal homeostasis and resistance in bacteria. Nat Rev Microbiol 2017; 15:338-350. [PMID: 28344348 DOI: 10.1038/nrmicro.2017.15] [Citation(s) in RCA: 412] [Impact Index Per Article: 58.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Metal ions are essential for many reactions, but excess metals can be toxic. In bacteria, metal limitation activates pathways that are involved in the import and mobilization of metals, whereas excess metals induce efflux and storage. In this Review, we highlight recent insights into metal homeostasis, including protein-based and RNA-based sensors that interact directly with metals or metal-containing cofactors. The resulting transcriptional response to metal stress takes place in a stepwise manner and is reinforced by post-transcriptional regulatory systems. Metal limitation and intoxication by the host are evolutionarily ancient strategies for limiting bacterial growth. The details of the resulting growth restriction are beginning to be understood and seem to be organism-specific.
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Affiliation(s)
- Pete Chandrangsu
- Department of Microbiology, Cornell University, Wing Hall, 123 Wing Drive, Ithaca, New York 14853, USA
| | - Christopher Rensing
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China.,Department of Agricultural Resource and Environment, College of Resources and the Environment, Fujian Agriculture &Forestry University, Boxbue Building, 15 Shangxiadian Road, Cangshan District, Fuzhou, Fujian 350002, China.,J. Craig Venter Institute, 4120 Capricorn Lane, La Jolla, California 92037, USA
| | - John D Helmann
- Department of Microbiology, Cornell University, Wing Hall, 123 Wing Drive, Ithaca, New York 14853, USA
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Marik A, Naiya H, Das M, Mukherjee G, Basu S, Saha C, Chowdhury R, Bhattacharyya K, Seal A. Split-ubiquitin yeast two-hybrid interaction reveals a novel interaction between a natural resistance associated macrophage protein and a membrane bound thioredoxin in Brassica juncea. PLANT MOLECULAR BIOLOGY 2016; 92:519-537. [PMID: 27534419 DOI: 10.1007/s11103-016-0528-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 08/10/2016] [Indexed: 06/06/2023]
Abstract
Natural resistance associated macrophage proteins (NRAMPs) are evolutionarily conserved metal transporters involved in the transport of essential and nonessential metals in plants. Fifty protein interactors of a Brassica juncea NRAMP protein was identified by a Split-Ubiquitin Yeast-Two-Hybrid screen. The interactors were predicted to function as components of stress response, signaling, development, RNA binding and processing. BjNRAMP4.1 interactors were particularly enriched in proteins taking part in photosynthetic or light regulated processes, or proteins predicted to be localized in plastid/chloroplast. Further, many interactors also had a suggested role in cellular redox regulation. Among these, the interaction of a photosynthesis-related thioredoxin, homologous to Arabidopsis HCF164 (High-chlorophyll fluorescence164) was studied in detail. Homology modeling of BjNRAMP4.1 suggested that it could be redox regulated by BjHCF164. In yeast, the interaction between the two proteins was found to increase in response to metal deficiency; Mn excess and exogenous thiol. Excess Mn also increased the interaction in planta and led to greater accumulation of the complex at the root apoplast. Network analysis of Arabidopsis homologs of BjNRAMP4.1 interactors showed enrichment of many protein components, central to chloroplastic/cellular ROS signaling. BjNRAMP4.1 interacted with BjHCF164 at the root membrane and also in the chloroplast in accordance with its proposed function related to photosynthesis, indicating that this interaction occurred at different sub-cellular locations depending on the tissue. This may serve as a link between metal homeostasis and chloroplastic/cellular ROS through protein-protein interaction.
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Affiliation(s)
- Ananya Marik
- Department of Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Haraprasad Naiya
- Department of Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Madhumanti Das
- Department of Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Gairik Mukherjee
- Department of Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Soumalee Basu
- Department of Microbiology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Chinmay Saha
- Department of Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India
| | - Rajdeep Chowdhury
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A and 2B Raja S.C Mullick Road, Jadavpur, Kolkata, 700032, India
| | - Kankan Bhattacharyya
- Department of Physical Chemistry, Indian Association for the Cultivation of Science, 2A and 2B Raja S.C Mullick Road, Jadavpur, Kolkata, 700032, India
| | - Anindita Seal
- Department of Biotechnology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India.
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28
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Hao X, Lüthje F, Rønn R, German NA, Li X, Huang F, Kisaka J, Huffman D, Alwathnani HA, Zhu YG, Rensing C. A role for copper in protozoan grazing - two billion years selecting for bacterial copper resistance. Mol Microbiol 2016; 102:628-641. [PMID: 27528008 DOI: 10.1111/mmi.13483] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/12/2016] [Indexed: 12/28/2022]
Abstract
The Great Oxidation Event resulted in integration of soft metals in a wide range of biochemical processes including, in our opinion, killing of bacteria by protozoa. Compared to pressure from anthropologic copper contamination, little is known on impacts of protozoan predation on maintenance of copper resistance determinants in bacteria. To evaluate the role of copper and other soft metals in predatory mechanisms of protozoa, we examined survival of bacteria mutated in different transition metal efflux or uptake systems in the social amoeba Dictyostelium discoideum. Our data demonstrated a strong correlation between the presence of copper/zinc efflux as well as iron/manganese uptake, and bacterial survival in amoebae. The growth of protozoa, in turn, was dependent on bacterial copper sensitivity. The phagocytosis of bacteria induced upregulation of Dictyostelium genes encoding the copper uptake transporter p80 and a triad of Cu(I)-translocating PIB -type ATPases. Accumulated Cu(I) in Dictyostelium was monitored using a copper biosensor bacterial strain. Altogether, our data demonstrate that Cu(I) is ultimately involved in protozoan predation of bacteria, supporting our hypothesis that protozoan grazing selected for the presence of copper resistance determinants for about two billion years.
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Affiliation(s)
- Xiuli Hao
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Freja Lüthje
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Regin Rønn
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Nadezhda A German
- Department of Pharmaceutical Sciences, Texas Tech University Health Sciences Center, Amarillo, TX, USA
| | - Xuanji Li
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Fuyi Huang
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Javan Kisaka
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - David Huffman
- Department of Chemistry, Western Michigan University, Kalamazoo, MI, USA
| | - Hend A Alwathnani
- Department of Botany and Microbiology, King Saud University, Riyadh, Saudi Arabia
| | - Yong-Guan Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China
| | - Christopher Rensing
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, China.,J. Craig Venter Institute, La Jolla, CA, USA
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Buracco S, Peracino B, Cinquetti R, Signoretto E, Vollero A, Imperiali F, Castagna M, Bossi E, Bozzaro S. Dictyostelium Nramp1, which is structurally and functionally similar to mammalian DMT1 transporter, mediates phagosomal iron efflux. J Cell Sci 2015; 128:3304-16. [PMID: 26208637 PMCID: PMC4582194 DOI: 10.1242/jcs.173153] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2015] [Accepted: 07/21/2015] [Indexed: 01/01/2023] Open
Abstract
The Nramp (Slc11) protein family is widespread in bacteria and eukaryotes, and mediates transport of divalent metals across cellular membranes. The social amoeba Dictyostelium discoideum has two Nramp proteins. Nramp1, like its mammalian ortholog (SLC11A1), is recruited to phagosomal and macropinosomal membranes, and confers resistance to pathogenic bacteria. Nramp2 is located exclusively in the contractile vacuole membrane and controls, synergistically with Nramp1, iron homeostasis. It has long been debated whether mammalian Nramp1 mediates iron import or export from phagosomes. By selectively loading the iron-chelating fluorochrome calcein in macropinosomes, we show that Dictyostelium Nramp1 mediates iron efflux from macropinosomes in vivo. To gain insight in ion selectivity and the transport mechanism, the proteins were expressed in Xenopus oocytes. Using a novel assay with calcein, and electrophysiological and radiochemical assays, we show that Nramp1, similar to rat DMT1 (also known as SLC11A2), transports Fe(2+) and manganese, not Fe(3+) or copper. Metal ion transport is electrogenic and proton dependent. By contrast, Nramp2 transports only Fe(2+) in a non-electrogenic and proton-independent way. These differences reflect evolutionary divergence of the prototypical Nramp2 protein sequence compared to the archetypical Nramp1 and DMT1 proteins.
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Affiliation(s)
- Simona Buracco
- Department of Clinical and Biological Sciences, University of Torino, AOU S. Luigi, Orbassano 10043, Italy
| | - Barbara Peracino
- Department of Clinical and Biological Sciences, University of Torino, AOU S. Luigi, Orbassano 10043, Italy
| | - Raffaella Cinquetti
- Department of Biotechnology and Life Sciences, University of Insubria, Via J. H. Dunant 3, Varese 21100, Italy
| | - Elena Signoretto
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Trentacoste 2, Milano 20133, Italy
| | - Alessandra Vollero
- Department of Biotechnology and Life Sciences, University of Insubria, Via J. H. Dunant 3, Varese 21100, Italy
| | - Francesca Imperiali
- Department of Biotechnology and Life Sciences, University of Insubria, Via J. H. Dunant 3, Varese 21100, Italy
| | - Michela Castagna
- Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Via Trentacoste 2, Milano 20133, Italy
| | - Elena Bossi
- Department of Biotechnology and Life Sciences, University of Insubria, Via J. H. Dunant 3, Varese 21100, Italy
| | - Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Torino, AOU S. Luigi, Orbassano 10043, Italy
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30
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Pan H, Wang Y, Zha Q, Yuan M, Yin L, Wu T, Zhang X, Xu X, Han Z. Iron deficiency stress can induce MxNRAMP1 protein endocytosis in M. xiaojinensis. Gene 2015; 567:225-34. [PMID: 25943636 DOI: 10.1016/j.gene.2015.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/23/2015] [Accepted: 05/01/2015] [Indexed: 12/21/2022]
Abstract
BACKGROUND Iron deficiency is one of the most common nutritional disorders in plants, especially in fruit trees grown in calcareous soil. Iron deficiency stress can induce a series of adaptive responses in plants, the cellular and molecular mechanisms of which remain unclear. NRAMPs (natural resistance-associated macrophage proteins) play an important role in divalent metal ion transportation. RESULTS In this study, we cloned MxNRAMP1, an NRAMP family gene from a highly iron-efficient apple genotype, Malus xiaojinensis. Further research showed that iron deficiency stress could induce MxNRAMP1 expression in roots and leaves. A protoplast transient expression system and immune electron microscopy localization techniques were used to prove that MxNRAMP1 mainly exists in the plasma membrane and vesicles. Interestingly, iron deficiency stress could induce the MxNRAMP protein to transport iron ions to specific organelles (lysosome and chloroplast) through vesicle endocytosis. Stable transgenic tobacco showed that MxNRAMP1 over-expression could promote iron absorption and accumulation in plants, and increase the plant's resistance against iron deficiency stress. CONCLUSIONS These results showed that, in M. xiaojinensis, MxNRAMP1 not only plays an important role in iron absorption and transportation, it can also produce adaptive responses against iron deficiency through endocytosis.
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Affiliation(s)
- Haifa Pan
- China Agricultural University, Beijing 100193, China; Key Laboratory of Genetic improvement and Ecophysiology of Horticultural Crop, Anhui Province, Institute of Horticulture, Anhui Academy of Agricultural Sciences, Hefei 230031, Anhui, China
| | - Yi Wang
- China Agricultural University, Beijing 100193, China
| | - Qian Zha
- China Agricultural University, Beijing 100193, China
| | - Mudan Yuan
- China Agricultural University, Beijing 100193, China
| | - Lili Yin
- China Agricultural University, Beijing 100193, China
| | - Ting Wu
- China Agricultural University, Beijing 100193, China
| | | | - Xuefeng Xu
- China Agricultural University, Beijing 100193, China
| | - Zhenhai Han
- China Agricultural University, Beijing 100193, China
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31
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Weber S, Stirnimann CU, Wieser M, Frey D, Meier R, Engelhardt S, Li X, Capitani G, Kammerer RA, Hilbi H. A type IV translocated Legionella cysteine phytase counteracts intracellular growth restriction by phytate. J Biol Chem 2014; 289:34175-88. [PMID: 25339170 DOI: 10.1074/jbc.m114.592568] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The causative agent of Legionnaires' pneumonia, Legionella pneumophila, colonizes diverse environmental niches, including biofilms, plant material, and protozoa. In these habitats, myo-inositol hexakisphosphate (phytate) is prevalent and used as a phosphate storage compound or as a siderophore. L. pneumophila replicates in protozoa and mammalian phagocytes within a unique "Legionella-containing vacuole." The bacteria govern host cell interactions through the Icm/Dot type IV secretion system (T4SS) and ∼300 different "effector" proteins. Here we characterize a hitherto unrecognized Icm/Dot substrate, LppA, as a phytate phosphatase (phytase). Phytase activity of recombinant LppA required catalytically essential cysteine (Cys(231)) and arginine (Arg(237)) residues. The structure of LppA at 1.4 Å resolution revealed a mainly α-helical globular protein stabilized by four antiparallel β-sheets that binds two phosphate moieties. The phosphates localize to a P-loop active site characteristic of dual specificity phosphatases or to a non-catalytic site, respectively. Phytate reversibly abolished growth of L. pneumophila in broth, and growth inhibition was relieved by overproduction of LppA or by metal ion titration. L. pneumophila lacking lppA replicated less efficiently in phytate-loaded Acanthamoeba castellanii or Dictyostelium discoideum, and the intracellular growth defect was complemented by the phytase gene. These findings identify the chelator phytate as an intracellular bacteriostatic component of cell-autonomous host immunity and reveal a T4SS-translocated L. pneumophila phytase that counteracts intracellular bacterial growth restriction by phytate. Thus, bacterial phytases might represent therapeutic targets to combat intracellular pathogens.
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Affiliation(s)
- Stephen Weber
- From the Max von Pettenkofer Institute, Department of Medicine, Ludwig-Maximilians University Munich, 80336 Munich, Germany
| | - Christian U Stirnimann
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Mara Wieser
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Daniel Frey
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Roger Meier
- the Scientific Center for Optical and Electron Microscopy, ETH Zurich, 8093 Zurich, Switzerland
| | - Sabrina Engelhardt
- the Institute of Veterinary Physiology and Zurich Center for Integrative Human Physiology (ZIHP), Vetsuisse Faculty, University of Zurich, 8057 Zurich, Switzerland, and
| | - Xiaodan Li
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Guido Capitani
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Richard A Kammerer
- the Laboratory of Biomolecular Research, Department of Biology and Chemistry, Paul Scherrer Institute, 5232 Villigen, Switzerland
| | - Hubert Hilbi
- From the Max von Pettenkofer Institute, Department of Medicine, Ludwig-Maximilians University Munich, 80336 Munich, Germany, the Institute of Medical Microbiology, Department of Medicine, University of Zurich, 8006 Zurich, Switzerland
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32
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Hoffmann C, Harrison CF, Hilbi H. The natural alternative: protozoa as cellular models forLegionellainfection. Cell Microbiol 2013; 16:15-26. [DOI: 10.1111/cmi.12235] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 12/22/2022]
Affiliation(s)
- Christine Hoffmann
- Max von Pettenkofer Institute; Department of Medicine; Ludwig-Maximilians University Munich; 80336 Munich Germany
| | - Christopher F. Harrison
- Max von Pettenkofer Institute; Department of Medicine; Ludwig-Maximilians University Munich; 80336 Munich Germany
| | - Hubert Hilbi
- Max von Pettenkofer Institute; Department of Medicine; Ludwig-Maximilians University Munich; 80336 Munich Germany
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33
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Bozzaro S, Buracco S, Peracino B. Iron metabolism and resistance to infection by invasive bacteria in the social amoeba Dictyostelium discoideum. Front Cell Infect Microbiol 2013; 3:50. [PMID: 24066281 PMCID: PMC3777012 DOI: 10.3389/fcimb.2013.00050] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Accepted: 08/22/2013] [Indexed: 12/20/2022] Open
Abstract
Dictyostelium cells are forest soil amoebae, which feed on bacteria and proliferate as solitary cells until bacteria are consumed. Starvation triggers a change in life style, forcing cells to gather into aggregates to form multicellular organisms capable of cell differentiation and morphogenesis. As a soil amoeba and a phagocyte that grazes on bacteria as the obligate source of food, Dictyostelium could be a natural host of pathogenic bacteria. Indeed, many pathogens that occasionally infect humans are hosted for most of their time in protozoa or free-living amoebae, where evolution of their virulence traits occurs. Due to these features and its amenability to genetic manipulation, Dictyostelium has become a valuable model organism for studying strategies of both the host to resist infection and the pathogen to escape the defense mechanisms. Similarly to higher eukaryotes, iron homeostasis is crucial for Dictyostelium resistance to invasive bacteria. Iron is essential for Dictyostelium, as both iron deficiency or overload inhibit cell growth. The Dictyostelium genome shares with mammals many genes regulating iron homeostasis. Iron transporters of the Nramp (Slc11A) family are represented with two genes, encoding Nramp1 and Nramp2. Like the mammalian ortholog, Nramp1 is recruited to phagosomes and macropinosomes, whereas Nramp2 is a membrane protein of the contractile vacuole network, which regulates osmolarity. Nramp1 and Nramp2 localization in distinct compartments suggests that both proteins synergistically regulate iron homeostasis. Rather than by absorption via membrane transporters, iron is likely gained by degradation of ingested bacteria and efflux via Nramp1 from phagosomes to the cytosol. Nramp gene disruption increases Dictyostelium sensitivity to infection, enhancing intracellular growth of Legionella or Mycobacteria. Generation of mutants in other "iron genes" will help identify genes essential for iron homeostasis and resistance to pathogens.
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Affiliation(s)
- Salvatore Bozzaro
- Department of Clinical and Biological Sciences, University of Torino, Orbassano, Italy.
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34
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Cellier MFM. Cell-Type Specific Determinants of NRAMP1 Expression in Professional Phagocytes. BIOLOGY 2013; 2:233-83. [PMID: 24832660 PMCID: PMC4009858 DOI: 10.3390/biology2010233] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/25/2012] [Revised: 01/15/2013] [Accepted: 01/15/2013] [Indexed: 01/10/2023]
Abstract
The Natural resistance-associated macrophage protein 1 (Nramp1 or Solute carrier 11 member 1, Slc11a1) transports divalent metals across the membrane of late endosomes and lysosomes in professional phagocytes. Nramp1 represents an ancient eukaryotic cell-autonomous defense whereas the gene duplication that yielded Nramp1 and Nramp2 predated the origin of Sarcopterygians (lobe-finned fishes and tetrapods). SLC11A1 genetic polymorphisms associated with human resistance to tuberculosis consist of potential regulatory variants. Herein, current knowledge of the regulation of SLC11A1 gene expression is reviewed and comprehensive analysis of ENCODE data available for hematopoietic cell-types suggests a hypothesis for the regulation of SLC11A1 expression during myeloid development and phagocyte functional polarization. SLC11A1 is part of a 34.6 kb CTCF-insulated locus scattered with predicted regulatory elements: a 3' enhancer, a large 5' enhancer domain and four elements spread around the transcription start site (TSS), including several C/EBP and PU.1 sites. SLC11A1 locus ends appear mobilized by ETS-related factors early during myelopoiesis; activation of both 5' and 3' enhancers in myelo-monocytic cells correlate with transcription factor binding at the TSS. Characterizing the corresponding cis/trans determinants functionally will establish the mechanisms involved and possibly reveal genetic variation that impacts susceptibility to infectious or immune diseases.
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Affiliation(s)
- Mathieu F M Cellier
- Inrs-Institut Armand-Frappier, 531, Bd des prairies, Laval, QC H7V 1B7, Canada.
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35
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Contractile Vacuole Complex—Its Expanding Protein Inventory. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2013; 306:371-416. [DOI: 10.1016/b978-0-12-407694-5.00009-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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