151
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Haschka D, Nairz M, Demetz E, Wienerroither S, Decker T, Weiss G. Contrasting regulation of macrophage iron homeostasis in response to infection with Listeria monocytogenes depending on localization of bacteria. Metallomics 2016; 7:1036-45. [PMID: 25869778 DOI: 10.1039/c4mt00328d] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Due to its multiple roles for the proliferation and pathogenicity of many microbes on the one hand and via modulation of immune effector functions on the other hand the control over iron homeostasis is thought to play a decisive role in the course of infections. Diversion of cellular iron traffic is considered as an important defense mechanism of macrophages to reduce metal availability for intracellular bacteria residing in the phagosome. However, evidence is lacking whether such alterations of iron homeostasis also become evident upon infection with bacteria gaining access to the cytosol like Listeria monocytogenes. Here we show that infection of macrophages with L. monocytogenes triggers the expression of the major cellular iron exporter ferroportin1 and induces cellular iron egress. As the growth of Listeria within macrophages is promoted by iron, stimulation of ferroportin1 functionality limits the availability of the metal for Listeria residing in the cytoplasm, whereas ferroportin1 degradation upon hepcidin treatment increases intracellular bacterial growth. In parallel to an increase of ferroportin1 expression, infected macrophages induce anti-microbial immune effector mechanisms such as TNFα formation or NO expression which are aggravated upon iron deficiency. These adaptive changes of iron homeostasis and immune response pathways are only found in macrophages infected with Listeria which express listeriolysin O and are therefore able to escape from the phagosome to the cytoplasm. Listeriolysin O deficient Listeria which are restricted to the phagosome are even killed by excess iron which may be based on "iron intoxification" via macrophage radical formation, because iron supplementation in that setting is paralleled by increased ROS formation. Our results indicate that ferroportin1 mediated iron export is a nutritional immune effector pathway to control infection with Listeria residing in the cytoplasm, whereas a different strategy is observed in mutant Listeria restricted to the phagosome, where iron remains in the macrophages likewise contributing to ROS mediated intoxification of bacteria.
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Affiliation(s)
- David Haschka
- Department of Internal Medicine VI, Medical University of Innsbruck, Anichstraße 35, A - 6020 Innsbruck, Austria.
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152
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Payne SM, Mey AR, Wyckoff EE. Vibrio Iron Transport: Evolutionary Adaptation to Life in Multiple Environments. Microbiol Mol Biol Rev 2016; 80:69-90. [PMID: 26658001 PMCID: PMC4711184 DOI: 10.1128/mmbr.00046-15] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Iron is an essential element for Vibrio spp., but the acquisition of iron is complicated by its tendency to form insoluble ferric complexes in nature and its association with high-affinity iron-binding proteins in the host. Vibrios occupy a variety of different niches, and each of these niches presents particular challenges for acquiring sufficient iron. Vibrio species have evolved a wide array of iron transport systems that allow the bacteria to compete for this essential element in each of its habitats. These systems include the secretion and uptake of high-affinity iron-binding compounds (siderophores) as well as transport systems for iron bound to host complexes. Transporters for ferric and ferrous iron not complexed to siderophores are also common to Vibrio species. Some of the genes encoding these systems show evidence of horizontal transmission, and the ability to acquire and incorporate additional iron transport systems may have allowed Vibrio species to more rapidly adapt to new environmental niches. While too little iron prevents growth of the bacteria, too much can be lethal. The appropriate balance is maintained in vibrios through complex regulatory networks involving transcriptional repressors and activators and small RNAs (sRNAs) that act posttranscriptionally. Examination of the number and variety of iron transport systems found in Vibrio spp. offers insights into how this group of bacteria has adapted to such a wide range of habitats.
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Affiliation(s)
- Shelley M Payne
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Alexandra R Mey
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
| | - Elizabeth E Wyckoff
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA
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153
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Pérez N, Johnson R, Sen B, Ramakrishnan G. Two parallel pathways for ferric and ferrous iron acquisition support growth and virulence of the intracellular pathogen Francisella tularensis Schu S4. Microbiologyopen 2016; 5:453-68. [PMID: 26918301 PMCID: PMC4905997 DOI: 10.1002/mbo3.342] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Revised: 01/10/2016] [Accepted: 01/14/2016] [Indexed: 12/17/2022] Open
Abstract
Iron acquisition mechanisms in Francisella tularensis, the causative agent of tularemia, include the Francisella siderophore locus (fsl) siderophore operon and a ferrous iron–transport system comprising outer‐membrane protein FupA and inner‐membrane transporter FeoB. To characterize these mechanisms and to identify any additional iron uptake systems in the virulent subspecies tularensis, single and double deletions were generated in the fsl and feo iron acquisition systems of the strain Schu S4. Deletion of the entire fsl operon caused loss of siderophore production that could be restored by complementation with the biosynthetic genes fslA and fslC and Major Facilitator Superfamily (MFS) transporter gene fslB. 55Fe‐transport assays demonstrated that siderophore‐iron uptake required the receptor FslE and MFS transporter FslD. A ΔfeoB′ mutation resulted in loss of ability to transport ferrous iron (55Fe2+). A ΔfeoB′ ΔfslA mutant that required added exogenous siderophore for growth in vitro was unable to grow within tissue culture cells and was avirulent in mice, indicating that no compensatory cryptic iron uptake systems were induced in vivo. These studies demonstrate that the fsl and feo pathways function independently and operate in parallel to effectively support virulence of F. tularensis.
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Affiliation(s)
- Natalie Pérez
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, 22908
| | - Richard Johnson
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, 22908
| | - Bhaswati Sen
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, 22908
| | - Girija Ramakrishnan
- Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, Virginia, 22908
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154
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Böser P, Mordashova Y, Maasland M, Trommer I, Lorenz H, Hafner M, Seemann D, Mueller BK, Popp A. Quantification of Hepcidin-related Iron Accumulation in the Rat Liver. Toxicol Pathol 2016; 44:259-66. [PMID: 26839325 DOI: 10.1177/0192623315623866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Hepcidin was originally detected as a liver peptide with antimicrobial activity and it functions as a central regulator in the systemic iron metabolism. Consequently suppression of hepcidin leads to iron accumulation in the liver. AbbVie developed a monoclonal antibody ([mAb]; repulsive guidance molecule [RGMa/c] mAb) that downregulates hepcidin expression by influencing the RGMc/bone morphogenetic protein (BMP)/neogenin receptor complex and causes iron deposition in the liver. In a dose range finding study with RGMa/c mAb, rats were treated with different dose levels for a total of 4 weekly doses. The results of this morphometric analysis in the liver showed that iron accumulation is not homogenous between liver lobes and the left lateral lobe was the most responsive lobe in the rat. Quantitative hepcidin messenger RNA analysis showed that the left lateral lobe was the most responsive lobe showing hepcidin downregulation with increasing antibody dose. In addition, the morphometric analysis had higher sensitivity than the chemical iron extraction and quantification using a colorimetric assay. In conclusion, the Prussian blue stain in combination with semi-quantitative and quantitative morphometric analysis is the most reliable method to demonstrate iron accumulation in the liver compared to direct measurement of iron in unfixed tissue using a colorimetric assay.
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Affiliation(s)
- Preethne Böser
- AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany Institute for Medical Technology, Heidelberg University and University of Applied Sciences Mannheim, Ludwigshafen, Germany
| | | | - Mark Maasland
- Fraunhofer Institute for Industrial Mathematics ITWM, Kaiserslautern, Ludwigshafen, Germany
| | | | - Helga Lorenz
- AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany
| | - Mathias Hafner
- Institute for Medical Technology, Heidelberg University and University of Applied Sciences Mannheim, Ludwigshafen, Germany
| | | | | | - Andreas Popp
- AbbVie Deutschland GmbH & Co. KG, Ludwigshafen, Germany
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155
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Kapetanovic R, Bokil NJ, Achard MES, Ong CLY, Peters KM, Stocks CJ, Phan MD, Monteleone M, Schroder K, Irvine KM, Saunders BM, Walker MJ, Stacey KJ, McEwan AG, Schembri MA, Sweet MJ. Salmonella employs multiple mechanisms to subvert the TLR-inducible zinc-mediated antimicrobial response of human macrophages. FASEB J 2016; 30:1901-12. [PMID: 26839376 DOI: 10.1096/fj.201500061] [Citation(s) in RCA: 65] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2015] [Accepted: 01/19/2016] [Indexed: 12/27/2022]
Abstract
We aimed to characterize antimicrobial zinc trafficking within macrophages and to determine whether the professional intramacrophage pathogen Salmonella enterica serovar Typhimurium (S Typhimurium) subverts this pathway. Using both Escherichia coli and S Typhimurium, we show that TLR signaling promotes the accumulation of vesicular zinc within primary human macrophages. Vesicular zinc is delivered to E. coli to promote microbial clearance, whereas S. Typhimurium evades this response via Salmonella pathogenicity island (SPI)-1. Even in the absence of SPI-1 and the zinc exporter ZntA, S Typhimurium resists the innate immune zinc stress response, implying the existence of additional host subversion mechanisms. We also demonstrate the combinatorial antimicrobial effects of zinc and copper, a pathway that S. Typhimurium again evades. Our use of complementary tools and approaches, including confocal microscopy, direct assessment of intramacrophage bacterial zinc stress responses, specific E. coli and S Typhimurium mutants, and inductively coupled plasma mass spectroscopy, has enabled carefully controlled characterization of this novel innate immune antimicrobial pathway. In summary, our study provides new insights at the cellular level into the well-documented effects of zinc in promoting host defense against infectious disease, as well as the complex host subversion strategies employed by S Typhimurium to combat this pathway.-Kapetanovic, R., Bokil, N. J., Achard, M. E. S., Ong, C.-L. Y., Peters, K. M., Stocks, C. J., Phan, M.-D., Monteleone, M., Schroder, K., Irvine, K. M., Saunders, B. M., Walker, M. J., Stacey, K. J., McEwan, A. G., Schembri, M. A., Sweet, M. J. Salmonella employs multiple mechanisms to subvert the TLR-inducible zinc-mediated antimicrobial response of human macrophages.
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Affiliation(s)
- Ronan Kapetanovic
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, Australia; IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Nilesh J Bokil
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, Australia; IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Maud E S Achard
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Cheryl-Lynn Y Ong
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Kate M Peters
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Claudia J Stocks
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, Australia; IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Minh-Duy Phan
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Mercedes Monteleone
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, Australia; IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Kate Schroder
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, Australia; IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Katharine M Irvine
- IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, Australia; School of Medicine, The University of Queensland, Woolloongabba, Australia; and
| | | | - Mark J Walker
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Katryn J Stacey
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Alastair G McEwan
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Mark A Schembri
- School of Chemistry and Molecular Biosciences, The University of Queensland, St. Lucia, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia
| | - Matthew J Sweet
- Institute for Molecular Bioscience (IMB), The University of Queensland, Brisbane, Australia; IMB Centre for Inflammation and Disease Research, The University of Queensland, Brisbane, Australia; Australian Infectious Diseases Research Centre, The University of Queensland, Brisbane, Australia;
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156
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Galay RL, Takechi R, Umemiya-Shirafuji R, Talactac MR, Maeda H, Kusakisako K, Mochizuki M, Fujisaki K, Tanaka T. Impaired cellular immune response to injected bacteria after knockdown of ferritin genes in the hard tick Haemaphysalis longicornis. Parasitol Int 2016; 65:251-7. [PMID: 26792075 DOI: 10.1016/j.parint.2016.01.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 12/18/2015] [Accepted: 01/10/2016] [Indexed: 11/12/2022]
Abstract
Iron is an indispensable element for most microorganisms, including many pathogenic bacteria. Iron-withholding is a known component of the innate immunity, particularly of vertebrate hosts. Ticks are vectors of multiple pathogens and reports have shown that they naturally harbor several bacterial species. Thus, tick innate immunity must be crucial in limiting bacterial population to tolerable level that will not cause adverse effects. We have previously characterized two types of the iron-binding protein ferritin (HlFER) in the hard tick Haemaphysalis longicornis, known to be a vector of some protozoan parasites and rickettsiae, and showed their antioxidant function and importance in blood feeding and reproduction. Here we examined the possible role of HlFERs in tick immunity against bacterial infection. After silencing Hlfer genes, adult ticks were injected with live enhanced green fluorescence protein-expressing Escherichia coli, and then monitored for survival rate. Hemolymph that included hemocytes was collected for microscopic examination to observe cellular immune response, and for E. coli culture to determine bacterial viability after injection in the ticks. The expression of some antimicrobial peptides in whole ticks was also analyzed by RT-PCR. Hlfer-silenced ticks had a significantly lower survival rate than control ticks after E. coli injection. Greater number of bacteria inside and outside the hemocytes and higher bacterial colony counts after culture with hemolymph were also observed in Hlfer-silenced ticks. However, no difference on the expression of antimicrobial peptides was observed. These results suggest that ferritin molecules might be important in the cellular immune response of ticks to some bacteria.
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Affiliation(s)
- Remil Linggatong Galay
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Rie Takechi
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan
| | - Rika Umemiya-Shirafuji
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
| | - Melbourne Rio Talactac
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan; Department of Clinical and Population Health, College of Veterinary Medicine and Biomedical Sciences, Cavite State University, Cavite 4122, Philippines
| | - Hiroki Maeda
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Kodai Kusakisako
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Masami Mochizuki
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Kozo Fujisaki
- Zen-noh Institute of Animal Health, 7 Ooja, Sakura, Chiba 285-0043, Japan
| | - Tetsuya Tanaka
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
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157
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Muraille E. The Unspecific Side of Acquired Immunity Against Infectious Disease: Causes and Consequences. Front Microbiol 2016; 6:1525. [PMID: 26793171 PMCID: PMC4707229 DOI: 10.3389/fmicb.2015.01525] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Accepted: 12/18/2015] [Indexed: 11/13/2022] Open
Abstract
Acquired immunity against infectious disease (AIID) has long been considered as strictly dependent on the B and T lymphocytes of the adaptive immune system. Consequently, AIID has been viewed as highly specific to the antigens expressed by pathogens. However, a growing body of data motivates revision of this central paradigm of immunology. Unrelated past infection, vaccination, and chronic infection have been found to induce cross-protection against numerous pathogens. These observations can be partially explained by the poly-specificity of antigenic T and B receptors, the Mackaness effect and trained immunity. In addition, numerous studies highlight the importance of microbiota composition on resistance to infectious disease via direct competition or modulation of the immune response. All of these data support the idea that a non-negligible part of AIID in nature can be nonspecific to the pathogens encountered and even of the antigens expressed by pathogens. As this protection may be dependent on the private T and B repertoires produced by the random rearrangement of genes, past immune history, chronic infection, and microbiota composition, it is largely unpredictable at the individual level. However, we can reasonably expect that a better understanding of the underlying mechanisms will allow us to statistically predict cross-protection at the population level. From an evolutionary perspective, selection of immune mechanisms allowing for partially nonspecific AIID would appear to be advantageous against highly polymorphic and rapidly evolving pathogens. This new emerging paradigm may have several important consequences on our understanding of individual infectious disease susceptibility and our conception of tolerance, vaccination and therapeutic strategies against infection and cancer. It also underscores the importance of viewing the microbiota and persisting infectious agents as integral parts of the immune system.
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Affiliation(s)
- Eric Muraille
- Laboratoire de Parasitologie, Faculté de Médecine, Université Libre de BruxellesBruxelles, Belgium
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158
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Kell DB, Kenny LC. A Dormant Microbial Component in the Development of Preeclampsia. Front Med (Lausanne) 2016; 3:60. [PMID: 27965958 PMCID: PMC5126693 DOI: 10.3389/fmed.2016.00060] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 11/04/2016] [Indexed: 12/12/2022] Open
Abstract
Preeclampsia (PE) is a complex, multisystem disorder that remains a leading cause of morbidity and mortality in pregnancy. Four main classes of dysregulation accompany PE and are widely considered to contribute to its severity. These are abnormal trophoblast invasion of the placenta, anti-angiogenic responses, oxidative stress, and inflammation. What is lacking, however, is an explanation of how these themselves are caused. We here develop the unifying idea, and the considerable evidence for it, that the originating cause of PE (and of the four classes of dysregulation) is, in fact, microbial infection, that most such microbes are dormant and hence resist detection by conventional (replication-dependent) microbiology, and that by occasional resuscitation and growth it is they that are responsible for all the observable sequelae, including the continuing, chronic inflammation. In particular, bacterial products such as lipopolysaccharide (LPS), also known as endotoxin, are well known as highly inflammagenic and stimulate an innate (and possibly trained) immune response that exacerbates the inflammation further. The known need of microbes for free iron can explain the iron dysregulation that accompanies PE. We describe the main routes of infection (gut, oral, and urinary tract infection) and the regularly observed presence of microbes in placental and other tissues in PE. Every known proteomic biomarker of "preeclampsia" that we assessed has, in fact, also been shown to be raised in response to infection. An infectious component to PE fulfills the Bradford Hill criteria for ascribing a disease to an environmental cause and suggests a number of treatments, some of which have, in fact, been shown to be successful. PE was classically referred to as endotoxemia or toxemia of pregnancy, and it is ironic that it seems that LPS and other microbial endotoxins really are involved. Overall, the recognition of an infectious component in the etiology of PE mirrors that for ulcers and other diseases that were previously considered to lack one.
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Affiliation(s)
- Douglas B. Kell
- School of Chemistry, The University of Manchester, Manchester, UK
- The Manchester Institute of Biotechnology, The University of Manchester, Manchester, UK
- Centre for Synthetic Biology of Fine and Speciality Chemicals, The University of Manchester, Manchester, UK
- *Correspondence: Douglas B. Kell,
| | - Louise C. Kenny
- The Irish Centre for Fetal and Neonatal Translational Research (INFANT), University College Cork, Cork, Ireland
- Department of Obstetrics and Gynecology, University College Cork, Cork, Ireland
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159
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Macdougall IC, Bircher AJ, Eckardt KU, Obrador GT, Pollock CA, Stenvinkel P, Swinkels DW, Wanner C, Weiss G, Chertow GM, Adamson JW, Akizawa T, Anker SD, Auerbach M, Bárány P, Besarab A, Bhandari S, Cabantchik I, Collins AJ, Coyne DW, de Francisco ÁL, Fishbane S, Gaillard CA, Ganz T, Goldsmith DJ, Hershko C, Jankowska EA, Johansen KL, Kalantar-Zadeh K, Kalra PA, Kasiske BL, Locatelli F, Małyszko J, Mayer G, McMahon LP, Mikhail A, Nemeth E, Pai AB, Parfrey PS, Pecoits-Filho R, Roger SD, Rostoker G, Rottembourg J, Singh AK, Slotki I, Spinowitz BS, Tarng DC, Tentori F, Toblli JE, Tsukamoto Y, Vaziri ND, Winkelmayer WC, Wheeler DC, Zakharova E. Iron management in chronic kidney disease: conclusions from a “Kidney Disease: Improving Global Outcomes” (KDIGO) Controversies Conference. Kidney Int 2016; 89:28-39. [DOI: 10.1016/j.kint.2015.10.002] [Citation(s) in RCA: 167] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 09/22/2015] [Accepted: 09/29/2015] [Indexed: 12/21/2022]
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160
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Wells M, Seyer L, Schadt K, Lynch DR. IFN-γ for Friedreich ataxia: present evidence. Neurodegener Dis Manag 2015; 5:497-504. [PMID: 26634868 DOI: 10.2217/nmt.15.52] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
IFN-γ-1b is currently US FDA approved as an orphan drug for the treatment of chronic granulomatous disease and severe malignant osteopetrosis. It is administered via subcutaneous injection and is a potential therapy for Friedreich ataxia (FRDA), a rare degenerative neurological condition. Ongoing Phase II and III trials in both adults and children with FRDA were preceded by a small Phase I, open-label trial in children that showed that IFN-γ-1b was reasonably well-tolerated and improved overall neurological function as measured by the Friedreich Ataxia Rating Scale after 12 weeks of treatment, though the primary outcome measure of frataxin level showed no improvement. Although there is an established dose of IFN-γ-1b prescribed for the current indications, the efficacy and tolerability of these dose levels in the FRDA population remains the subject of ongoing investigation.
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Affiliation(s)
- McKenzie Wells
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lauren Seyer
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Kimberly Schadt
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - David R Lynch
- Departments of Pediatrics & Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, USA.,Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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161
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Aznar A, Chen NWG, Thomine S, Dellagi A. Immunity to plant pathogens and iron homeostasis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2015; 240:90-7. [PMID: 26475190 DOI: 10.1016/j.plantsci.2015.08.022] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2015] [Revised: 08/27/2015] [Accepted: 08/28/2015] [Indexed: 05/07/2023]
Abstract
Iron is essential for metabolic processes in most living organisms. Pathogens and their hosts often compete for the acquisition of this nutrient. However, iron can catalyze the formation of deleterious reactive oxygen species. Hosts may use iron to increase local oxidative stress in defense responses against pathogens. Due to this duality, iron plays a complex role in plant-pathogen interactions. Plant defenses against pathogens and plant response to iron deficiency share several features, such as secretion of phenolic compounds, and use common hormone signaling pathways. Moreover, fine tuning of iron localization during infection involves genes coding iron transport and iron storage proteins, which have been shown to contribute to immunity. The influence of the plant iron status on the outcome of a given pathogen attack is strongly dependent on the nature of the pathogen infection strategy and on the host species. Microbial siderophores emerged as important factors as they have the ability to trigger plant defense responses. Depending on the plant species, siderophore perception can be mediated by their strong iron scavenging capacity or possibly via specific recognition as pathogen associated molecular patterns. This review highlights that iron has a key role in several plant-pathogen interactions by modulating immunity.
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Affiliation(s)
- Aude Aznar
- Institut Jean-Pierre Bourgin, UMR INRA-AgroParisTech 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France
| | - Nicolas W G Chen
- Institut de Recherche en Horticulture et Semences, UMR1345 INRA-AgroCampus-Ouest, F-49045 Angers, France
| | - Sebastien Thomine
- Institute for Integrative Biology of the Cell (I2BC), CNRS, Gif-sur-Yvette 91198, France
| | - Alia Dellagi
- Institut Jean-Pierre Bourgin, UMR INRA-AgroParisTech 1318, ERL CNRS 3559, Saclay Plant Sciences, RD10, F-78026 Versailles, France.
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Lewis JD, Chen EZ, Baldassano RN, Otley AR, Griffiths AM, Lee D, Bittinger K, Bailey A, Friedman ES, Hoffmann C, Albenberg L, Sinha R, Compher C, Gilroy E, Nessel L, Grant A, Chehoud C, Li H, Wu GD, Bushman FD. Inflammation, Antibiotics, and Diet as Environmental Stressors of the Gut Microbiome in Pediatric Crohn's Disease. Cell Host Microbe 2015; 18:489-500. [PMID: 26468751 PMCID: PMC4633303 DOI: 10.1016/j.chom.2015.09.008] [Citation(s) in RCA: 527] [Impact Index Per Article: 58.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Revised: 07/31/2015] [Accepted: 09/22/2015] [Indexed: 12/13/2022]
Abstract
Abnormal composition of intestinal bacteria--"dysbiosis"-is characteristic of Crohn's disease. Disease treatments include dietary changes and immunosuppressive anti-TNFα antibodies as well as ancillary antibiotic therapy, but their effects on microbiota composition are undetermined. Using shotgun metagenomic sequencing, we analyzed fecal samples from a prospective cohort of pediatric Crohn's disease patients starting therapy with enteral nutrition or anti-TNFα antibodies and reveal the full complement and dynamics of bacteria, fungi, archaea, and viruses during treatment. Bacterial community membership was associated independently with intestinal inflammation, antibiotic use, and therapy. Antibiotic exposure was associated with increased dysbiosis, whereas dysbiosis decreased with reduced intestinal inflammation. Fungal proportions increased with disease and antibiotic use. Dietary therapy had independent and rapid effects on microbiota composition distinct from other stressor-induced changes and effectively reduced inflammation. These findings reveal that dysbiosis results from independent effects of inflammation, diet, and antibiotics and shed light on Crohn disease treatments.
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Affiliation(s)
- James D Lewis
- Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA; Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Eric Z Chen
- Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Robert N Baldassano
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Anthony R Otley
- Department of Pediatrics, IWK Health Centre, Halifax, NS B3K 6R8, Canada
| | - Anne M Griffiths
- Division of Gastroenterology Hepatology and Nutrition, Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Dale Lee
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Division of Pediatric Gastroenterology Hepatology and Nutrition, Seattle Children's Hospital, University of Washington, Seattle, WA 98105, USA
| | - Kyle Bittinger
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Aubrey Bailey
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Elliot S Friedman
- Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Christian Hoffmann
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lindsey Albenberg
- Department of Pediatric Gastroenterology Hepatology and Nutrition, Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA
| | - Rohini Sinha
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Charlene Compher
- School of Nursing, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Erin Gilroy
- Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Lisa Nessel
- Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Amy Grant
- Department of Pediatrics, IWK Health Centre, Halifax, NS B3K 6R8, Canada
| | - Christel Chehoud
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Hongzhe Li
- Center for Clinical Epidemiology and Biostatistics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Gary D Wu
- Division of Gastroenterology, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Frederic D Bushman
- Department of Microbiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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163
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Buffler M, Becker C, Windisch W, Schümann K. Inflammation neither increases hepatic hepcidin nor affects intestinal (59)Fe-absorption in two murine models of bowel inflammation, hemizygous TNF(ΔARE/+) and homozygous IL-10(-/-) mice. J Trace Elem Med Biol 2015; 32:162-7. [PMID: 26302924 DOI: 10.1016/j.jtemb.2015.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 07/06/2015] [Accepted: 07/06/2015] [Indexed: 01/25/2023]
Abstract
Hepcidin-synthesis was reported to be stimulated by inflammation. In contrast, hepcidin synthesis was inhibited by TNFα and serum hepcidin was low. To elucidate these contradictions, we compare data on hepcidin expression, on iron absorption and homoeostasis and markers of inflammation between two murine models of intestinal inflammation and corresponding wild-types as determined by standard methods. In TNF(ΔARE/+) and IL-10(-/-)-mice hepatic hepcidin expression and protein content was significantly lower than in corresponding wild-types. However, (59)Fe whole-body retention showed no difference between knock-outs and corresponding wild-types 7d after gavage, in neither strain. Compared to wild-types, body weight, hepatic non-haem iron content, hemoglobin and hematocrit were significantly decreased in TNF(ΔARE/+) mice, while erythropoiesis increased. These differences were not seen in IL-10(-/-) mice. Duodenal IL-6 and TNFα content increased significantly in TNF(ΔARE/+) mice, while ferritin-H decreased along with hepatic hepcidin expression, ferritin L, and non-haem iron. In IL-10(-/-) mice, these changes were less marked or missing for non-haem iron. Duodenal ferritin-L and ferroportin increased significantly, while HFE decreased. Our results corroborate the conflicting combination of low hepcidin with inflammation and without increased intestinal iron absorption. Speculating on underlying mechanism, decreased hepcidin may result from stimulated erythropoiesis. Unaltered intestinal iron-absorption may compromise between the stimulation by increased erythropoiesis and inhibition by local and systemic inflammation. The findings suggest intense interaction between counterproductive mechanisms and ask for further research.
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Affiliation(s)
- M Buffler
- Chair of Animal Nutrition, TUM School of Life Sciences, Technische Universität München, Germany
| | - C Becker
- Chair of Animal Nutrition, TUM School of Life Sciences, Technische Universität München, Germany.
| | - W Windisch
- Chair of Animal Nutrition, TUM School of Life Sciences, Technische Universität München, Germany
| | - K Schümann
- Research Center for Nutrition and Food Science (ZIEL), TUM School of Life Sciences, Technische Universität München, Germany
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164
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Nairz M, Schroll A, Haschka D, Dichtl S, Sonnweber T, Theurl I, Theurl M, Lindner E, Demetz E, Aßhoff M, Bellmann-Weiler R, Müller R, Gerner RR, Moschen AR, Baumgartner N, Moser PL, Talasz H, Tilg H, Fang FC, Weiss G. Lipocalin-2 ensures host defense against Salmonella Typhimurium by controlling macrophage iron homeostasis and immune response. Eur J Immunol 2015; 45:3073-86. [PMID: 26332507 DOI: 10.1002/eji.201545569] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2015] [Revised: 07/28/2015] [Accepted: 08/27/2015] [Indexed: 01/01/2023]
Abstract
Lipocalin-2 (Lcn2) is an innate immune peptide with pleiotropic effects. Lcn2 binds iron-laden bacterial siderophores, chemo-attracts neutrophils and has immunomodulatory and apoptosis-regulating effects. In this study, we show that upon infection with Salmonella enterica serovar Typhimurium, Lcn2 promotes iron export from Salmonella-infected macrophages, which reduces cellular iron content and enhances the generation of pro-inflammatory cytokines. Lcn2 represses IL-10 production while augmenting Nos2, TNF-α, and IL-6 expression. Lcn2(-/-) macrophages have elevated IL-10 levels as a consequence of increased iron content. The crucial role of Lcn-2/IL-10 interactions was further demonstrated by the greater ability of Lcn2(-/-) IL-10(-/-) macrophages and mice to control intracellular Salmonella proliferation in comparison to Lcn2(-/-) counterparts. Overexpression of the iron exporter ferroportin-1 in Lcn2(-/-) macrophages represses IL-10 and restores TNF-α and IL-6 production to the levels found in wild-type macrophages, so that killing and clearance of intracellular Salmonella is promoted. Our observations suggest that Lcn2 promotes host resistance to Salmonella Typhimurium infection by binding bacterial siderophores and suppressing IL-10 production, and that both functions are linked to its ability to shuttle iron from macrophages.
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Affiliation(s)
- Manfred Nairz
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Andrea Schroll
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - David Haschka
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Stefanie Dichtl
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Thomas Sonnweber
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Igor Theurl
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Milan Theurl
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Ewald Lindner
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Egon Demetz
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Malte Aßhoff
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Rosa Bellmann-Weiler
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Raphael Müller
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Romana R Gerner
- Department of Internal Medicine I, Gastroenterology, Endocrinology and Metabolism, Medical University of Innsbruck, Austria
| | - Alexander R Moschen
- Department of Internal Medicine I, Gastroenterology, Endocrinology and Metabolism, Medical University of Innsbruck, Austria
| | - Nadja Baumgartner
- Department of Internal Medicine II, Gastroenterology and Hepatology, Medical University of Innsbruck, Austria
| | - Patrizia L Moser
- Department of Pathology, Medical University of Innsbruck, Austria
| | - Heribert Talasz
- Biocenter, Division of Clinical Biochemistry, Medical University of Innsbruck, Austria
| | - Herbert Tilg
- Department of Internal Medicine I, Gastroenterology, Endocrinology and Metabolism, Medical University of Innsbruck, Austria
| | - Ferric C Fang
- Departments of Laboratory Medicine and Microbiology, University of Washington, Seattle, USA
| | - Günter Weiss
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
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165
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Bhandari S, Kalra PA, Kothari J, Ambühl PM, Christensen JH, Essaian AM, Thomsen LL, Macdougall IC, Coyne DW. A randomized, open-label trial of iron isomaltoside 1000 (Monofer®) compared with iron sucrose (Venofer®) as maintenance therapy in haemodialysis patients. Nephrol Dial Transplant 2015; 30:1577-89. [PMID: 25925701 PMCID: PMC4550440 DOI: 10.1093/ndt/gfv096] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 03/13/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Iron deficiency anaemia is common in patients with chronic kidney disease, and intravenous iron is the preferred treatment for those on haemodialysis. The aim of this trial was to compare the efficacy and safety of iron isomaltoside 1000 (Monofer®) with iron sucrose (Venofer®) in haemodialysis patients. METHODS This was an open-label, randomized, multicentre, non-inferiority trial conducted in 351 haemodialysis subjects randomized 2:1 to either iron isomaltoside 1000 (Group A) or iron sucrose (Group B). Subjects in Group A were equally divided into A1 (500 mg single bolus injection) and A2 (500 mg split dose). Group B were also treated with 500 mg split dose. The primary end point was the proportion of subjects with haemoglobin (Hb) in the target range 9.5-12.5 g/dL at 6 weeks. Secondary outcome measures included haematology parameters and safety parameters. RESULTS A total of 351 subjects were enrolled. Both treatments showed similar efficacy with >82% of subjects with Hb in the target range (non-inferiority, P = 0.01). Similar results were found when comparing subgroups A1 and A2 with Group B. No statistical significant change in Hb concentration was found between any of the groups. There was a significant increase in ferritin from baseline to Weeks 1, 2 and 4 in Group A compared with Group B (Weeks 1 and 2: P < 0.001; Week 4: P = 0.002). There was a significant higher increase in reticulocyte count in Group A compared with Group B at Week 1 (P < 0.001). The frequency, type and severity of adverse events were similar. CONCLUSIONS Iron isomaltoside 1000 and iron sucrose have comparative efficacy in maintaining Hb concentrations in haemodialysis subjects and both preparations were well tolerated with a similar short-term safety profile.
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Affiliation(s)
| | | | - Jatin Kothari
- P. D. Hinduja National Hospital and Research Center Mumbai, Mumbai, India
| | - Patrice M. Ambühl
- Leiter Abteilung Nephrologie, Stadtspital Waid Zürich, Zürich, Switzerland
| | | | | | | | | | - Daniel W. Coyne
- Washington University School of Medicine St. Louis, St. Louis, MO, USA
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166
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Musiani F, Ciurli S. Evolution of Macromolecular Docking Techniques: The Case Study of Nickel and Iron Metabolism in Pathogenic Bacteria. Molecules 2015; 20:14265-92. [PMID: 26251891 PMCID: PMC6332059 DOI: 10.3390/molecules200814265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 07/23/2015] [Accepted: 07/28/2015] [Indexed: 11/24/2022] Open
Abstract
The interaction between macromolecules is a fundamental aspect of most biological processes. The computational techniques used to study protein-protein and protein-nucleic acid interactions have evolved in the last few years because of the development of new algorithms that allow the a priori incorporation, in the docking process, of experimentally derived information, together with the possibility of accounting for the flexibility of the interacting molecules. Here we review the results and the evolution of the techniques used to study the interaction between metallo-proteins and DNA operators, all involved in the nickel and iron metabolism of pathogenic bacteria, focusing in particular on Helicobacter pylori (Hp). In the first part of the article we discuss the methods used to calculate the structure of complexes of proteins involved in the activation of the nickel-dependent enzyme urease. In the second part of the article, we concentrate on two applications of protein-DNA docking conducted on the transcription factors HpFur (ferric uptake regulator) and HpNikR (nickel regulator). In both cases we discuss the technical expedients used to take into account the conformational variability of the multi-domain proteins involved in the calculations.
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Affiliation(s)
- Francesco Musiani
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, Bologna I-40127, Italy.
| | - Stefano Ciurli
- Laboratory of Bioinorganic Chemistry, Department of Pharmacy and Biotechnology, University of Bologna, Viale G. Fanin 40, Bologna I-40127, Italy.
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167
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Roles of the TonB1 and TonB2 proteins in haemin iron acquisition and virulence in Riemerella anatipestifer. Microbiology (Reading) 2015; 161:1592-1599. [DOI: 10.1099/mic.0.000123] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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168
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Adherent-Invasive Escherichia coli Production of Cellulose Influences Iron-Induced Bacterial Aggregation, Phagocytosis, and Induction of Colitis. Infect Immun 2015. [PMID: 26216423 DOI: 10.1128/iai.00904-15] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Adherent-invasive Escherichia coli (AIEC), a functionally distinct subset of resident intestinal E. coli associated with Crohn's disease, is characterized by enhanced epithelial adhesion and invasion, survival within macrophages, and biofilm formation. Environmental factors, such as iron, modulate E. coli production of extracellular structures, which in turn influence the formation of multicellular communities, such as biofilms, and bacterial interactions with host cells. However, the physiological and functional responses of AIEC to variable iron availability have not been thoroughly investigated. We therefore characterized the impact of iron on the physiology of AIEC strain NC101 and subsequent interactions with macrophages. Iron promoted the cellulose-dependent aggregation of NC101. Bacterial cells recovered from the aggregates were more susceptible to phagocytosis than planktonic cells, which corresponded with the decreased macrophage production of the proinflammatory cytokine interleukin-12 (IL-12) p40. Prevention of aggregate formation through the disruption of cellulose production reduced the phagocytosis of iron-exposed NC101. In contrast, under iron-limiting conditions, where NC101 aggregation is not induced, the disruption of cellulose production enhanced NC101 phagocytosis and decreased macrophage secretion of IL-12 p40. Finally, abrogation of cellulose production reduced NC101 induction of colitis when NC101 was monoassociated in inflammation-prone Il10(-/-) mice. Taken together, our results introduce cellulose as a novel physiological factor that impacts host-microbe-environment interactions and alters the proinflammatory potential of AIEC.
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169
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Dickson CF, Jacques DA, Clubb RT, Guss JM, Gell DA. The structure of haemoglobin bound to the haemoglobin receptor IsdH from Staphylococcus aureus shows disruption of the native α-globin haem pocket. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2015; 71:1295-306. [PMID: 26057669 PMCID: PMC8518021 DOI: 10.1107/s1399004715005817] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 03/23/2015] [Indexed: 12/13/2022]
Abstract
Staphylococcus aureus is a common and serious cause of infection in humans. The bacterium expresses a cell-surface receptor that binds to, and strips haem from, human haemoglobin (Hb). The binding interface has previously been identified; however, the structural changes that promote haem release from haemoglobin were unknown. Here, the structure of the receptor-Hb complex is reported at 2.6 Å resolution, which reveals a conformational change in the α-globin F helix that disrupts the haem-pocket structure and alters the Hb quaternary interactions. These features suggest potential mechanisms by which the S. aureus Hb receptor induces haem release from Hb.
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170
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Liao H, Cheng X, Zhu D, Wang M, Jia R, Chen S, Chen X, Biville F, Liu M, Cheng A. TonB Energy Transduction Systems of Riemerella anatipestifer Are Required for Iron and Hemin Utilization. PLoS One 2015; 10:e0127506. [PMID: 26017672 PMCID: PMC4446302 DOI: 10.1371/journal.pone.0127506] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 04/16/2015] [Indexed: 12/13/2022] Open
Abstract
Riemerella anatipestifer (R. anatipestifer) is one of the most important pathogens in ducks. The bacteria causes acute or chronic septicemia characterized by fibrinous pericarditis and meningitis. The R. anatipestifer genome encodes multiple iron/hemin-uptake systems that facilitate adaptation to iron-limited host environments. These systems include several TonB-dependent transporters and three TonB proteins responsible for energy transduction. These three tonB genes are present in all the R. anatipestifer genomes sequenced so far. Two of these genes are contained within the exbB-exbD-tonB1 and exbB-exbD-exbD-tonB2 operons. The third, tonB3, forms a monocistronic transcription unit. The inability to recover derivatives deleted for this gene suggests its product is essential for R. anatipestifer growth. Here, we show that deletion of tonB1 had no effect on hemin uptake of R. anatipestifer, though disruption of tonB2 strongly decreases hemin uptake, and disruption of both tonB1 and tonB2 abolishes the transport of exogenously added hemin. The ability of R. anatipestifer to grow on iron-depleted medium is decreased by tonB2 but not tonB1 disruption. When expressed in an E. coli model strain, the TonB1 complex, TonB2 complex, and TonB3 protein from R. anatipestifer cannot energize heterologous hemin transporters. Further, only the TonB1 complex can energize a R. anatipestifer hemin transporter when co-expressed in an E. coli model strain.
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Affiliation(s)
- HeBin Liao
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
| | - XingJun Cheng
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
| | - DeKang Zhu
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
| | - MingShu Wang
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
| | - RenYong Jia
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
| | - Shun Chen
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
| | - XiaoYue Chen
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
| | - Francis Biville
- Unité des Infections Bactériennes Invasives, Institut Pasteur, Paris, France
| | - MaFeng Liu
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- * E-mail: (ML); (AC)
| | - AnChun Cheng
- Avian Disease Research Center, College of Veterinary Medicine of Sichuan Agricultural University, Ya’an, Sichuan, People’s Republic of China
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- Key Laboratory of Animal Disease and Human Health of Sichuan Province, Sichuan Agricultural University, Chengdu, Sichuan, People’s Republic of China
- * E-mail: (ML); (AC)
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Iron Homeostasis and Trypanosoma brucei Associated Immunopathogenicity Development: A Battle/Quest for Iron. BIOMED RESEARCH INTERNATIONAL 2015; 2015:819389. [PMID: 26090446 PMCID: PMC4450282 DOI: 10.1155/2015/819389] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 02/11/2015] [Accepted: 02/15/2015] [Indexed: 12/24/2022]
Abstract
African trypanosomosis is a chronic debilitating disease affecting the health and economic well-being of developing countries. The immune response during African trypanosome infection consisting of a strong proinflammatory M1-type activation of the myeloid phagocyte system (MYPS) results in iron deprivation for these extracellular parasites. Yet, the persistence of M1-type MYPS activation causes the development of anemia (anemia of chronic disease, ACD) as a most prominent pathological parameter in the mammalian host, due to enhanced erythrophagocytosis and retention of iron within the MYPS thereby depriving iron for erythropoiesis. In this review we give an overview of how parasites acquire iron from the host and how iron modulation of the host MYPS affects trypanosomosis-associated anemia development. Finally, we also discuss different strategies at the level of both the host and the parasite that can/might be used to modulate iron availability during African trypanosome infections.
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172
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Strategies of Intracellular Pathogens for Obtaining Iron from the Environment. BIOMED RESEARCH INTERNATIONAL 2015; 2015:476534. [PMID: 26120582 PMCID: PMC4450229 DOI: 10.1155/2015/476534] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 02/09/2015] [Indexed: 12/22/2022]
Abstract
Most microorganisms are destroyed by the host tissues through processes that usually involve phagocytosis and lysosomal disruption. However, some organisms, called intracellular pathogens, are capable of avoiding destruction by growing inside macrophages or other cells. During infection with intracellular pathogenic microorganisms, the element iron is required by both the host cell and the pathogen that inhabits the host cell. This minireview focuses on how intracellular pathogens use multiple strategies to obtain nutritional iron from the intracellular environment in order to use this element for replication. Additionally, the implications of these mechanisms for iron acquisition in the pathogen-host relationship are discussed.
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173
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Singh V, Yeoh BS, Xiao X, Kumar M, Bachman M, Borregaard N, Joe B, Vijay-Kumar M. Interplay between enterobactin, myeloperoxidase and lipocalin 2 regulates E. coli survival in the inflamed gut. Nat Commun 2015; 6:7113. [PMID: 25964185 DOI: 10.1038/ncomms8113] [Citation(s) in RCA: 72] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 04/07/2015] [Indexed: 12/15/2022] Open
Abstract
During an inflammatory response in the gut, some commensal bacteria such as E. coli can thrive and contribute to disease. Here we demonstrate that enterobactin (Ent), a catecholate siderophore released by E. coli, is a potent inhibitor of myeloperoxidase (MPO), a bactericidal enzyme of the host. Glycosylated Ent (salmochelin) and non-catecholate siderophores (yersiniabactin and ferrichrome) fail to inhibit MPO activity. An E. coli mutant (ΔfepA) that overproduces Ent, but not an Ent-deficient double mutant (ΔaroB/ΔfepA), inhibits MPO activity and exhibits enhanced survival in inflamed guts. This survival advantage is counter-regulated by lipocalin 2, a siderophore-binding host protein, which rescues MPO from Ent-mediated inhibition. Spectral analysis reveals that Ent interferes with compound I [oxoiron, Fe(IV)=O] and reverts the enzyme back to its native ferric [Fe(III)] state. These findings define a fundamental mechanism by which E. coli surpasses the host innate immune responses during inflammatory gut diseases and gains a distinct survival advantage.
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Affiliation(s)
- Vishal Singh
- Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Beng San Yeoh
- Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Xia Xiao
- Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Manish Kumar
- Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Michael Bachman
- Department of Pathology, University of Michigan, Ann Arbor, Michigan 48109-5602, USA
| | - Niels Borregaard
- Department of Hematology, The Granulocyte Research Laboratory, National University Hospital, University of Copenhagen, Copenhagen 2100, Denmark
| | - Bina Joe
- Department of Physiology and Pharmacology, Center for Hypertension and Personalized Medicine, The University of Toledo College of Medicine and Life Sciences, Toledo, Ohio 43614, USA
| | - Matam Vijay-Kumar
- 1] Department of Nutritional Sciences, Pennsylvania State University, University Park, Pennsylvania 16802, USA [2] Department of Medicine, Pennsylvania State University Medical Center, Hershey, Pennsylvania 17033, USA
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174
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Lee D, Albenberg L, Compher C, Baldassano R, Piccoli D, Lewis JD, Wu GD. Diet in the pathogenesis and treatment of inflammatory bowel diseases. Gastroenterology 2015; 148:1087-106. [PMID: 25597840 PMCID: PMC4409494 DOI: 10.1053/j.gastro.2015.01.007] [Citation(s) in RCA: 265] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 01/12/2015] [Accepted: 01/13/2015] [Indexed: 12/14/2022]
Abstract
Some of the most common symptoms of the inflammatory bowel diseases (IBD, which include ulcerative colitis and Crohn's disease) are abdominal pain, diarrhea, and weight loss. It is therefore not surprising that clinicians and patients have wondered whether dietary patterns influence the onset or course of IBD. The question of what to eat is among the most commonly asked by patients, and among the most difficult to answer for clinicians. There are substantial variations in dietary behaviors of patients and recommendations for them, although clinicians do not routinely endorse specific diets for patients with IBD. Dietary clinical trials have been limited by their inability to include a placebo control, contamination of study groups, and inclusion of patients receiving medical therapies. Additional challenges include accuracy of information on dietary intake, complex interactions between foods consumed, and differences in food metabolism among individuals. We review the roles of diet in the etiology and management of IBD based on plausible mechanisms and clinical evidence. Researchers have learned much about the effects of diet on the mucosal immune system, epithelial function, and the intestinal microbiome; these findings could have significant practical implications. Controlled studies of patients receiving enteral nutrition and observations made from patients on exclusion diets have shown that components of whole foods can have deleterious effects for patients with IBD. Additionally, studies in animal models suggested that certain nutrients can reduce intestinal inflammation. In the future, engineered diets that restrict deleterious components but supplement beneficial nutrients could be used to modify the luminal intestinal environment of patients with IBD; these might be used alone or in combination with immunosuppressive agents, or as salvage therapy for patients who do not respond or lose responsiveness to medical therapies. Stricter diets might be required to induce remission, and more sustainable exclusion diets could be used to maintain long-term remission.
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Affiliation(s)
| | | | | | | | | | - James D. Lewis
- Co-Corresponding authors: James D. Lewis, Professor of Medicine and Epidemiology, Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, 720 Blockley Hall, 423 Guardian Drive, Philadelphia, PA 19104-6021, Office: (215) 573-5137, Fax: (215) 573-0813, ; Gary D. Wu, Professor of Medicine, Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Suite 915, Biomedical Research Building, 421 Curie Boulevard, Philadelphia, PA 19104, Office: (215) 898-0158, Fax: (215) 573-2024,
| | - Gary D. Wu
- Co-Corresponding authors: James D. Lewis, Professor of Medicine and Epidemiology, Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, 720 Blockley Hall, 423 Guardian Drive, Philadelphia, PA 19104-6021, Office: (215) 573-5137, Fax: (215) 573-0813, ; Gary D. Wu, Professor of Medicine, Division of Gastroenterology, Perelman School of Medicine, University of Pennsylvania, Suite 915, Biomedical Research Building, 421 Curie Boulevard, Philadelphia, PA 19104, Office: (215) 898-0158, Fax: (215) 573-2024,
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175
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Dhama K, Saminathan M, Jacob SS, Singh M, Karthik K, . A, Tiwari R, Sunkara LT, Malik YS, Singh RK. Effect of Immunomodulation and Immunomodulatory Agents on Health with some Bioactive Principles, Modes of Action and Potent Biomedical Applications. INT J PHARMACOL 2015. [DOI: 10.3923/ijp.2015.253.290] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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176
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Iron Depletion Enhances Production of Antimicrobials by Pseudomonas aeruginosa. J Bacteriol 2015; 197:2265-75. [PMID: 25917911 DOI: 10.1128/jb.00072-15] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 04/23/2015] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED Cystic fibrosis (CF) is a heritable disease characterized by chronic, polymicrobial lung infections. While Staphylococcus aureus is the dominant lung pathogen in young CF patients, Pseudomonas aeruginosa becomes predominant by adulthood. P. aeruginosa produces a variety of antimicrobials that likely contribute to this shift in microbial populations. In particular, secretion of 2-alkyl-4(1H)-quinolones (AQs) contributes to lysis of S. aureus in coculture, providing an iron source to P. aeruginosa both in vitro and in vivo. We previously showed that production of one such AQ, the Pseudomonas quinolone signal (PQS), is enhanced by iron depletion and that this induction is dependent upon the iron-responsive PrrF small RNAs (sRNAs). Here, we demonstrate that antimicrobial activity against S. aureus during coculture is also enhanced by iron depletion, and we provide evidence that multiple AQs contribute to this activity. Strikingly, a P. aeruginosa ΔprrF mutant, which produces very little PQS in monoculture, was capable of mediating iron-regulated growth suppression of S. aureus. We show that the presence of S. aureus suppresses the ΔprrF1,2 mutant's defect in iron-regulated PQS production, indicating that a PrrF-independent iron regulatory pathway mediates AQ production in coculture. We further demonstrate that iron-regulated antimicrobial production is conserved in multiple P. aeruginosa strains, including clinical isolates from CF patients. These results demonstrate that iron plays a central role in modulating interactions of P. aeruginosa with S. aureus. Moreover, our studies suggest that established iron regulatory pathways of these pathogens are significantly altered during polymicrobial infections. IMPORTANCE Chronic polymicrobial infections involving Pseudomonas aeruginosa and Staphylococcus aureus are a significant cause of morbidity and mortality, as the interplay between these two organisms exacerbates infection. This is in part due to enhanced production of antimicrobial metabolites by P. aeruginosa when these two species are cocultured. Using both established and newly developed coculture techniques, this report demonstrates that iron depletion increases P. aeruginosa's ability to suppress growth of S. aureus. These findings present a novel role for iron in modulating microbial interaction and provide the basis for understanding how essential nutrients drive polymicrobial infections.
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177
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Becker C, Orozco M, Solomons NW, Schümann K. Iron metabolism in obesity: how interaction between homoeostatic mechanisms can interfere with their original purpose. Part I: underlying homoeostatic mechanisms of energy storage and iron metabolisms and their interaction. J Trace Elem Med Biol 2015; 30:195-201. [PMID: 25467855 DOI: 10.1016/j.jtemb.2014.10.011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Revised: 10/29/2014] [Accepted: 10/29/2014] [Indexed: 02/07/2023]
Abstract
Adipose tissue plasticity mediated by inflammation is an important evolutionary achievement to survive seasonal climate changes. It permits to store excessive calories and to release them if required, using inflammatory cells to remove the debris. This process is regulated by a complex interaction of cytokines (TNF-α, IL-6), adipokines (adiponectin, apelin, liptin), adhesion molecules (ICAM-1, VCAM-1, E-selectin) and transcription factors (NF-κB, HIF-1α). Iron mediates electron transfer as an essential component of e.g. myeloperoxidase, hemoglobin, cytochrome C and ribonucleotide reductase. Conversely, unbound iron can catalyze oxidation of lipids, proteins, and DNA. To balance the essential with the potentially toxic function requires an efficient iron homoeostasis. This is mediated by hepcidin's interaction with the iron-exporter ferroportin, to adapt intestinal iron absorption and body iron-sequestration to changes in demand. In addition, the interaction of iron-responsive elements (IRE) and iron-responsive proteins (IRP), the IRE/IRP-mechanism, regulates cellular iron homoeostasis. Obesity-induced inflammation interacts with both these mechanisms and disturbs iron availability by impairing its absorption, and by sequestering it in the reticuloendothelial system. Both mechanisms lead to anemia and reduce physical fitness which, in a vicious cycle, can support the development of pathological obesity. Thus, interaction between these two sets of beneficial regulatory mechanisms can become detrimental in situations of ample calorie supply.
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Affiliation(s)
- Christiane Becker
- Institut für Tierernährung der TUM, Freising-Weihenstephan, Germany.
| | - Mónica Orozco
- Center for Studies of Sensory Impairment, Aging and Metabolism (CeSSIAM), Guatemala, Guatemala; Universidad de Valles, Solola, Guatemala
| | - Noel W Solomons
- Center for Studies of Sensory Impairment, Aging and Metabolism (CeSSIAM), Guatemala, Guatemala
| | - Klaus Schümann
- Research Center for Nutrition and Food Science (ZIEL) der TUM, Freising-Weihenstephan, Germany
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178
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Abstract
UNLABELLED Grapevine is a well-studied, economically relevant crop, whose associated bacteria could influence its organoleptic properties. In this study, the spatial and temporal dynamics of the bacterial communities associated with grapevine organs (leaves, flowers, grapes, and roots) and soils were characterized over two growing seasons to determine the influence of vine cultivar, edaphic parameters, vine developmental stage (dormancy, flowering, preharvest), and vineyard. Belowground bacterial communities differed significantly from those aboveground, and yet the communities associated with leaves, flowers, and grapes shared a greater proportion of taxa with soil communities than with each other, suggesting that soil may serve as a bacterial reservoir. A subset of soil microorganisms, including root colonizers significantly enriched in plant growth-promoting bacteria and related functional genes, were selected by the grapevine. In addition to plant selective pressure, the structure of soil and root microbiota was significantly influenced by soil pH and C:N ratio, and changes in leaf- and grape-associated microbiota were correlated with soil carbon and showed interannual variation even at small spatial scales. Diazotrophic bacteria, e.g., Rhizobiaceae and Bradyrhizobium spp., were significantly more abundant in soil samples and root samples of specific vineyards. Vine-associated microbial assemblages were influenced by myriad factors that shape their composition and structure, but the majority of organ-associated taxa originated in the soil, and their distribution reflected the influence of highly localized biogeographic factors and vineyard management. IMPORTANCE Vine-associated bacterial communities may play specific roles in the productivity and disease resistance of their host plant. Also, the bacterial communities on grapes have the potential to influence the organoleptic properties of the wine, contributing to a regional terroir. Understanding that factors that influence these bacteria may provide insights into management practices to shape and craft individual wine properties. We show that soil serves as a key source of vine-associated bacteria and that edaphic factors and vineyard-specific properties can influence the native grapevine microbiome preharvest.
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179
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Zarraonaindia I, Owens SM, Weisenhorn P, West K, Hampton-Marcell J, Lax S, Bokulich NA, Mills DA, Martin G, Taghavi S, van der Lelie D, Gilbert JA. The soil microbiome influences grapevine-associated microbiota. mBio 2015; 6:mBio.02527-14. [PMID: 25805735 DOI: 10.1128/mbio.02527-14.editor] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2023] Open
Abstract
UNLABELLED Grapevine is a well-studied, economically relevant crop, whose associated bacteria could influence its organoleptic properties. In this study, the spatial and temporal dynamics of the bacterial communities associated with grapevine organs (leaves, flowers, grapes, and roots) and soils were characterized over two growing seasons to determine the influence of vine cultivar, edaphic parameters, vine developmental stage (dormancy, flowering, preharvest), and vineyard. Belowground bacterial communities differed significantly from those aboveground, and yet the communities associated with leaves, flowers, and grapes shared a greater proportion of taxa with soil communities than with each other, suggesting that soil may serve as a bacterial reservoir. A subset of soil microorganisms, including root colonizers significantly enriched in plant growth-promoting bacteria and related functional genes, were selected by the grapevine. In addition to plant selective pressure, the structure of soil and root microbiota was significantly influenced by soil pH and C:N ratio, and changes in leaf- and grape-associated microbiota were correlated with soil carbon and showed interannual variation even at small spatial scales. Diazotrophic bacteria, e.g., Rhizobiaceae and Bradyrhizobium spp., were significantly more abundant in soil samples and root samples of specific vineyards. Vine-associated microbial assemblages were influenced by myriad factors that shape their composition and structure, but the majority of organ-associated taxa originated in the soil, and their distribution reflected the influence of highly localized biogeographic factors and vineyard management. IMPORTANCE Vine-associated bacterial communities may play specific roles in the productivity and disease resistance of their host plant. Also, the bacterial communities on grapes have the potential to influence the organoleptic properties of the wine, contributing to a regional terroir. Understanding that factors that influence these bacteria may provide insights into management practices to shape and craft individual wine properties. We show that soil serves as a key source of vine-associated bacteria and that edaphic factors and vineyard-specific properties can influence the native grapevine microbiome preharvest.
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Affiliation(s)
| | | | - Pamela Weisenhorn
- Computation Institute, University of Chicago, Chicago, Illinois, USA
| | - Kristin West
- Center of Excellence for Agricultural Biosolutions, FMC Corporation, Research Triangle Park, North Carolina, USA
| | | | - Simon Lax
- Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, USA
| | - Nicholas A Bokulich
- Departments of Viticulture and Enology; Food Science and Technology; Foods for Health Institute, University of California, Davis, California, USA
| | - David A Mills
- Departments of Viticulture and Enology; Food Science and Technology; Foods for Health Institute, University of California, Davis, California, USA
| | | | - Safiyh Taghavi
- Center of Excellence for Agricultural Biosolutions, FMC Corporation, Research Triangle Park, North Carolina, USA
| | - Daniel van der Lelie
- Center of Excellence for Agricultural Biosolutions, FMC Corporation, Research Triangle Park, North Carolina, USA
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180
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Spoils of war: iron at the crux of clinical and ecological fitness of Pseudomonas aeruginosa. Biometals 2015; 28:433-43. [DOI: 10.1007/s10534-015-9848-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 03/13/2015] [Indexed: 01/07/2023]
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181
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Abstract
Macrophages and neutrophils play a decisive role in host responses to intracellular bacteria including the agent of tuberculosis (TB), Mycobacterium tuberculosis as they represent the forefront of innate immune defense against bacterial invaders. At the same time, these phagocytes are also primary targets of intracellular bacteria to be abused as host cells. Their efficacy to contain and eliminate intracellular M. tuberculosis decides whether a patient initially becomes infected or not. However, when the infection becomes chronic or even latent (as in the case of TB) despite development of specific immune activation, phagocytes have also important effector functions. Macrophages have evolved a myriad of defense strategies to combat infection with intracellular bacteria such as M. tuberculosis. These include induction of toxic anti-microbial effectors such as nitric oxide and reactive oxygen intermediates, the stimulation of microbe intoxication mechanisms via acidification or metal accumulation in the phagolysosome, the restriction of the microbe's access to essential nutrients such as iron, fatty acids, or amino acids, the production of anti-microbial peptides and cytokines, along with induction of autophagy and efferocytosis to eliminate the pathogen. On the other hand, M. tuberculosis, as a prime example of a well-adapted facultative intracellular bacterium, has learned during evolution to counter-balance the host's immune defense strategies to secure survival or multiplication within this otherwise hostile environment. This review provides an overview of innate immune defense of macrophages directed against intracellular bacteria with a focus on M. tuberculosis. Gaining more insights and knowledge into this complex network of host-pathogen interaction will identify novel target sites of intervention to successfully clear infection at a time of rapidly emerging multi-resistance of M. tuberculosis against conventional antibiotics.
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Affiliation(s)
- Günter Weiss
- Department of Internal Medicine VI, Infectious Disease, Immunology, Rheumatology, Pneumology, Medical University of InnsbruckInnsbruck, Austria
| | - Ulrich E Schaible
- Cellular Microbiology, Priority Area Infections, Research Center BorstelBorstel, Germany
- Department of Immunology, London School of Hygiene and Tropical MedicineLondon, UK
- German Centre of Infection Research, TTU-TBBorstel, Germany
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182
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What a difference a cluster makes: The multifaceted roles of IscR in gene regulation and DNA recognition. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2015; 1854:1101-12. [PMID: 25641558 DOI: 10.1016/j.bbapap.2015.01.010] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2014] [Accepted: 01/21/2015] [Indexed: 11/22/2022]
Abstract
Iron-sulfur clusters are essential cofactors in a myriad of metabolic pathways. Therefore, their biogenesis is tightly regulated across a variety of organisms and environmental conditions. In Gram-negative bacteria, two pathways - ISC and SUF - concur for maintaining intracellular iron-sulfur cluster balance. Recently, the mechanism of iron-sulfur cluster biosynthesis regulation by IscR, an iron-sulfur cluster-containing regulator encoded by the isc operon, was found to be conserved in some Gram-positive bacteria. Belonging to the Rrf2 family of transcriptional regulators, IscR displays a single helix-turn-helix DNA-binding domain but is able to recognize two distinct DNA sequence motifs, switching its specificity upon cluster ligation. This review provides an overview of gene regulation by iron-sulfur cluster-containing sensors, in the light of the recent structural characterization of cluster-less free and DNA-bound IscR, which provided insights into the molecular mechanism of nucleotide sequence recognition and discrimination of this unique transcription factor. This article is part of a Special Issue entitled: Cofactor-dependent proteins: evolution, chemical diversity and bio-applications.
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183
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Blocking yersiniabactin import attenuates extraintestinal pathogenic Escherichia coli in cystitis and pyelonephritis and represents a novel target to prevent urinary tract infection. Infect Immun 2015; 83:1443-50. [PMID: 25624354 DOI: 10.1128/iai.02904-14] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The emergence and spread of extended-spectrum beta-lactamases and carbapenemases among common bacterial pathogens are threatening our ability to treat routine hospital- and community-acquired infections. With the pipeline for new antibiotics virtually empty, there is an urgent need to develop novel therapeutics. Bacteria require iron to establish infection, and specialized pathogen-associated iron acquisition systems like yersiniabactin, common among pathogenic species in the family Enterobacteriaceae, including multidrug-resistant Klebsiella pneumoniae and pathogenic Escherichia coli, represent potentially novel therapeutic targets. Although the yersiniabactin system was recently identified as a vaccine target for uropathogenic E. coli (UPEC)-mediated urinary tract infection (UTI), its contribution to UPEC pathogenesis is unknown. Using an E. coli mutant (strain 536ΔfyuA) unable to acquire yersiniabactin during infection, we established the yersiniabactin receptor as a UPEC virulence factor during cystitis and pyelonephritis, a fitness factor during bacteremia, and a surface-accessible target of the experimental FyuA vaccine. In addition, we determined through transcriptome sequencing (RNA-seq) analyses of RNA from E. coli causing cystitis in women that iron acquisition systems, including the yersiniabactin system, are highly expressed by bacteria during natural uncomplicated UTI. Given that yersiniabactin contributes to the virulence of several pathogenic species in the family Enterobacteriaceae, including UPEC, and is frequently associated with multidrug-resistant strains, it represents a promising novel target to combat antibiotic-resistant infections.
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184
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Vazquez-Gutierrez P, Lacroix C, Jaeggi T, Zeder C, Zimmerman MB, Chassard C. Bifidobacteria strains isolated from stools of iron deficient infants can efficiently sequester iron. BMC Microbiol 2015; 15:3. [PMID: 25591860 PMCID: PMC4320568 DOI: 10.1186/s12866-014-0334-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 12/18/2014] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Bifidobacteria is one of the major gut commensal groups found in infants. Their colonization is commonly associated with beneficial effects to the host through mechanisms like niche occupation and nutrient competition against pathogenic bacteria. Iron is an essential element necessary for most microorganisms, including bifidobacteria and efficient competition for this micronutrient is linked to proliferation and persistence. For this research we hypothesized that bifidobacteria in the gut of iron deficient infants can efficiently sequester iron. The aim of the present study was to isolate bifidobacteria in fecal samples of iron deficient Kenyan infants and to characterize siderophore production and iron internalization capacity. RESULTS Fifty-six bifidobacterial strains were isolated by streaking twenty-eight stool samples from Kenyan infants, in enrichment media. To target strains with high iron sequestration mechanisms, a strong iron chelator 2,2-dipyridyl was supplemented to the agar media. Bifidobacterial isolates were first identified to species level by 16S rRNA sequencing, yielding B. bifidum (19 isolates), B. longum (15), B. breve (11), B. kashiwanohense (7), B. pseudolongum (3) and B. pseudocatenulatum (1). While most isolated bifidobacterial species are commonly encountered in the infantile gut, B. kashiwanohense was not frequently reported in infant feces. Thirty strains from culture collections and 56 isolates were characterized for their siderophore production, tested by the CAS assay. Siderophore activity ranged from 3 to 89% siderophore units, with 35 strains (41%) exhibiting high siderophore activity, and 31 (36%) and 20 (23%) showing intermediate or low activity. The amount of internalized iron of 60 bifidobacteria strains selected for their siderophore activity, was in a broad range from 8 to118 μM Fe. Four strains, B. pseudolongum PV8-2, B. kashiwanohense PV20-2, B. bifidum PV28-2a and B. longum PV5-1 isolated from infant stool samples were selected for both high siderophore activity and iron internalization. CONCLUSIONS A broad diversity of bifidobacteria were isolated in infant stools using iron limited conditions, with some strains exhibiting high iron sequestration properties. The ability of bifidobacteria to efficiently utilize iron sequestration mechanism such as siderophore production and iron internalization may confer an ecological advantage and be the basis for enhanced competition against enteropathogens.
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Affiliation(s)
- Pamela Vazquez-Gutierrez
- Laboratory of Food Biotechnology, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, Zurich, Switzerland.
| | - Christophe Lacroix
- Laboratory of Food Biotechnology, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, Zurich, Switzerland.
| | - Tanja Jaeggi
- Laboratory of Human Nutrition, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, Zurich, Switzerland.
| | - Christophe Zeder
- Laboratory of Human Nutrition, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, Zurich, Switzerland.
| | - Michael Bruce Zimmerman
- Laboratory of Human Nutrition, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, Zurich, Switzerland.
| | - Christophe Chassard
- Laboratory of Food Biotechnology, ETH Zurich, Institute of Food, Nutrition and Health, Schmelzbergstrasse 7, Zurich, Switzerland.
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185
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Oide S, Berthiller F, Wiesenberger G, Adam G, Turgeon BG. Individual and combined roles of malonichrome, ferricrocin, and TAFC siderophores in Fusarium graminearum pathogenic and sexual development. Front Microbiol 2015; 5:759. [PMID: 25628608 PMCID: PMC4290682 DOI: 10.3389/fmicb.2014.00759] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/12/2014] [Indexed: 11/15/2022] Open
Abstract
Intra- and extracellular iron-chelating siderophores produced by fungal non-ribosomal peptide synthetases have been shown to be involved in reproductive and pathogenic developmental processes and in iron and oxidative stress management. Here we report individual and combined contributions of three of these metabolites to developmental success of the destructive cereal pathogen Fusarium graminearum. In previous work, we determined that deletion of the NPS2 gene, responsible for intracellular siderophore biosynthesis, results in inability to produce sexual spores when mutants of this homothallic ascomycete are selfed. Deletion of the NPS6 gene, required for extracellular siderophore biosynthesis, does not affect sexual reproduction but results in sensitivity to iron starvation and oxidative stress and leads to reduced virulence to the host. Building on this, we report that double mutants lacking both NPS2 and NPS6 are augmented in all collective phenotypes of single deletion strains (i.e., abnormal sexual and pathogenic development, hypersensitivity to oxidative and iron-depletion stress), which suggests overlap of function. Using comparative biochemical analysis of wild-type and mutant strains, we show that NPS1, a third gene associated with siderophore biosynthesis, is responsible for biosynthesis of a second extracellular siderophore, malonichrome. nps1 mutants fail to produce this metabolite. Phenotypic characterization reveals that, although single nps1 mutants are like wild-type with respect to sexual development, hypersensitivity to ROS and iron-depletion stress, and virulence to the host, triple nps1nps2nps6 deletion strains, lacking all three siderophores, are even more impaired in these attributes than double nps2nps6 strains. Thus, combinatorial mutants lacking key iron-associated genes uncovered malonichrome function. The intimate connection between presence/absence of siderophores and resistance/sensitivity to ROS is central to sexual and pathogenic development.
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Affiliation(s)
- Shinichi Oide
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University Ithaca, NY, USA ; The Research Institute of Innovative Technology for the Earth (RITE) Kizugawa-Shi, Japan
| | - Franz Berthiller
- Department of Agrobiotechnology (IFA-Tulln), Center for Analytical Chemistry, University of Natural Resources and Life Sciences Vienna, Austria
| | - Gerlinde Wiesenberger
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna, Austria
| | - Gerhard Adam
- Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences Vienna, Austria
| | - B Gillian Turgeon
- Plant Pathology and Plant-Microbe Biology Section, School of Integrative Plant Science, Cornell University Ithaca, NY, USA
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186
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Ascenzi P, di Masi A, Leboffe L, Frangipani E, Nardini M, Verde C, Visca P. Structural Biology of Bacterial Haemophores. Adv Microb Physiol 2015; 67:127-76. [PMID: 26616517 DOI: 10.1016/bs.ampbs.2015.09.002] [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] [Indexed: 12/13/2022]
Abstract
Iron plays a key role in a wide range of metabolic and signalling functions representing an essential nutrient for almost all forms of life. However, the ferric form is hardly soluble, whereas the ferrous form is highly toxic. Thus, in biological fluids, most of the iron is sequestered in iron- or haem-binding proteins and the level of free iron is low, making haem and iron acquisition a challenge for pathogenic bacteria during infections. Although toxic to the host, free haem is a major and readily available source of iron for several pathogenic microorganisms. Both Gram-positive and Gram-negative bacteria have developed several strategies to acquire free haem-Fe and protein-bound haem-Fe. Haemophores are a class of secreted and cell surface-exposed proteins promoting free-haem uptake, haem extraction from host haem proteins, and haem presentation to specific outer-membrane receptors that internalize the metal-porphyrins. Here, structural biology of bacterial haemophores is reviewed focusing on haem acquisition, haem internalization, and haem-degrading systems.
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Affiliation(s)
- Paolo Ascenzi
- Laboratorio Interdipartimentale di Microscopia Elettronica, Università Roma Tre, Roma, Italy; Istituto di Bioscienze e BioRisorse, Consiglio Nazionale delle Ricerche, Napoli, Italy.
| | | | - Loris Leboffe
- Dipartimento di Scienze, Università Roma Tre, Roma, Italy
| | | | - Marco Nardini
- Dipartimento di Bioscienze, Università di Milano, Milano, Italy
| | - Cinzia Verde
- Istituto di Bioscienze e BioRisorse, Consiglio Nazionale delle Ricerche, Napoli, Italy; Dipartimento di Scienze, Università Roma Tre, Roma, Italy
| | - Paolo Visca
- Dipartimento di Scienze, Università Roma Tre, Roma, Italy
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187
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Early Stages of Infection After Pathogen Entry. MIMS' PATHOGENESIS OF INFECTIOUS DISEASE 2015. [PMCID: PMC7173478 DOI: 10.1016/b978-0-12-397188-3.00003-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
In this chapter, we describe the early stages of the pathogenic cycle involving entry into the host. For example, some bacteria may enter into epithelial cells, proliferate and then spread at the epithelial surface before being transmitted to another host. Some pathogens then migrate past the epithelial layer to deeper tissues causing invasive infections. Examples of some of the major bacterial, viral and fungal pathogens affecting the epithelial surfaces in the body are provided. The body produces a strong inflammatory immune response to pathogens at the epithelial surface. An introduction to the components of the inflammatory response including the phagocytic cells and the lymphatic system is provided. In addition, the nutritional requirements for invading bacteria including the importance of iron is discussed.
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188
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Galay RL, Umemiya-Shirafuji R, Mochizuki M, Fujisaki K, Tanaka T. Iron metabolism in hard ticks (Acari: Ixodidae): the antidote to their toxic diet. Parasitol Int 2014; 64:182-9. [PMID: 25527065 DOI: 10.1016/j.parint.2014.12.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 12/01/2014] [Accepted: 12/09/2014] [Indexed: 12/21/2022]
Abstract
Ticks are notorious parasitic arthropods, known for their completely host-blood-dependent lifestyle. Hard ticks (Acari: Ixodidae) feed on their hosts for several days and can ingest blood more than a hundred times their unfed weight. Their blood-feeding habit facilitates the transmission of various pathogens. It is remarkable how hard ticks cope with the toxic nature of their blood meal, which contains several molecules that can promote oxidative stress including iron. While it is required in several physiological processes, high amounts of iron can be dangerous because iron can also participate in the formation of free radicals that may cause cellular damage and death. Here we review the current knowledge on heme and inorganic iron metabolism in hard ticks and compare it with that in vertebrates and other arthropods. We briefly discuss the studies on heme transport, storage and detoxification, and the transport and storage of inorganic iron, with emphasis on the functions of tick ferritins. This review points out other aspects of tick iron metabolism that warrant further investigation, as compared to mammals and other arthropods. Further understanding of this physiological process may help in formulating new control strategies for tick infestation and the spread of tick-borne diseases.
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Affiliation(s)
- Remil Linggatong Galay
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Rika Umemiya-Shirafuji
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan
| | - Masami Mochizuki
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan
| | - Kozo Fujisaki
- National Agricultural and Food Research Organization, 3-1-5 Kannondai, Tsukuba, Ibaraki 305-0856, Japan
| | - Tetsuya Tanaka
- Department of Pathological and Preventive Veterinary Science, The United Graduate School of Veterinary Science, Yamaguchi University, Yoshida, Yamaguchi 753-8515, Japan; Laboratory of Infectious Diseases, Joint Faculty of Veterinary Medicine, Kagoshima University, 1-21-24 Korimoto, Kagoshima 890-0065, Japan.
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189
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The prrF-encoded small regulatory RNAs are required for iron homeostasis and virulence of Pseudomonas aeruginosa. Infect Immun 2014; 83:863-75. [PMID: 25510881 DOI: 10.1128/iai.02707-14] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen that requires iron to cause infection, but it also must regulate the uptake of iron to avoid iron toxicity. The iron-responsive PrrF1 and PrrF2 small regulatory RNAs (sRNAs) are part of P. aeruginosa's iron regulatory network and affect the expression of at least 50 genes encoding iron-containing proteins. The genes encoding the PrrF1 and PrrF2 sRNAs are encoded in tandem in P. aeruginosa, allowing for the expression of a distinct, heme-responsive sRNA named PrrH that appears to regulate genes involved in heme metabolism. Using a combination of growth, mass spectrometry, and gene expression analysis, we showed that the ΔprrF1,2 mutant, which lacks expression of the PrrF and PrrH sRNAs, is defective for both iron and heme homeostasis. We also identified phuS, encoding a heme binding protein involved in heme acquisition, and vreR, encoding a previously identified regulator of P. aeruginosa virulence genes, as novel targets of prrF-mediated heme regulation. Finally, we showed that the prrF locus encoding the PrrF and PrrH sRNAs is required for P. aeruginosa virulence in a murine model of acute lung infection. Moreover, we showed that inoculation with a ΔprrF1,2 deletion mutant protects against future challenge with wild-type P. aeruginosa. Combined, these data demonstrate that the prrF-encoded sRNAs are critical regulators of P. aeruginosa virulence.
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190
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Dilek N, Dilek AR, Sahin K, Kaklıkkaya N, Saral Y. Hepcidin expression in psoriasis patients. Indian J Dermatol 2014; 59:630. [PMID: 25484411 PMCID: PMC4248519 DOI: 10.4103/0019-5154.143564] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Background: Iron is an essential nutrient for mammals. Accelerated loss of nutrients through hyperproliferation and desquamation from the skin in psoriasis is known. Hepcidin is an important and recently discovered regulator of iron homeostasis. Aims and Objectives: The present study was undertaken to investigate the hepcidin expression in psoriasis patients. Materials and Methods: We examined peripheral blood cell counts, serum Fe, ferritin, interleukin-6 (IL-6) and hepcidin levels using respectively automated hematology analyzer, Iron assay on the AEROSET system, chemiluminescent microparticle immunoassay with automated analyzer, and enzyme-linked immunosorbent assay. Results: The independent comparison of Fe, ferritin, IL-6 and hepcidin levels in psoriasis patients and control group (healthy volunteers) revealed lower Fe and higher IL-6, hepcidin levels in psoriasis patients. No significant difference was seen in the ferritin level between the psoriasis and the control group. Conclusions: We think that studies on hepcidin expression in psoriatic plaques will contribute to our understanding the role of iron and hepcidin in the pathogenesis of psoriasis.
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Affiliation(s)
- Nursel Dilek
- Department of Dermatology, Recep Tayyip Erdoğan University, Medical Faculty Hospital, Rize, Turkey
| | - Aziz Ramazan Dilek
- Department of Microbiology, Recep Tayyip Erdoğan University, Medical Faculty Hospital, Rize, Turkey
| | - Kazim Sahin
- Department of Microbiology, Recep Tayyip Erdoğan University, Medical Faculty Hospital, Rize, Turkey
| | - Neşe Kaklıkkaya
- Department of Microbiology, Black Sea Technical University, Trabzon, Turkey
| | - Yunus Saral
- Department of Dermatology, Recep Tayyip Erdoğan University, Medical Faculty Hospital, Rize, Turkey
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191
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Zitt E, Sturm G, Kronenberg F, Neyer U, Knoll F, Lhotta K, Weiss G. Iron supplementation and mortality in incident dialysis patients: an observational study. PLoS One 2014; 9:e114144. [PMID: 25462819 PMCID: PMC4252084 DOI: 10.1371/journal.pone.0114144] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2014] [Accepted: 11/03/2014] [Indexed: 01/25/2023] Open
Abstract
BACKGROUND Studies on the association between iron supplementation and mortality in dialysis patients are rare and conflicting. METHODS In our observational single-center cohort study (INVOR study) we prospectively studied 235 incident dialysis patients. Time-dependent Cox proportional hazards models using all measured laboratory values for up to 7.6 years were applied to study the association between iron supplementation and all-cause mortality, cardiovascular and sepsis-related mortality. Furthermore, the time-dependent association of ferritin levels with mortality in patients with normal C-reactive protein (CRP) levels (<0.5 mg/dL) and elevated CRP levels (≧0.5 mg/dL) was evaluated by using non-linear P-splines to allow flexible modeling of the association. RESULTS One hundred and ninety-one (81.3%) patients received intravenous iron, 13 (5.5%) patients oral iron, whereas 31 (13.2%) patients were never supplemented with iron throughout the observation period. Eighty-two (35%) patients died during a median follow-up of 34 months, 38 patients due to cardiovascular events and 21 patients from sepsis. Baseline CRP levels were not different between patients with and without iron supplementation. However, baseline serum ferritin levels were lower in patients receiving iron during follow up (median 93 vs 251 ng/mL, p<0.001). Iron supplementation was associated with a significantly reduced all-cause mortality [HR (95%CI): 0.22 (0.08-0.58); p = 0.002] and a reduced cardiovascular and sepsis-related mortality [HR (95%CI): 0.31 (0.09-1.04); p = 0.06]. Increasing ferritin concentrations in patients with normal CRP were associated with a decreasing mortality, whereas in patients with elevated CRP values ferritin levels>800 ng/mL were linked with increased mortality. CONCLUSIONS Iron supplementation is associated with reduced all-cause mortality in incident dialysis patients. While serum ferritin levels up to 800 ng/mL appear to be safe, higher ferritin levels are associated with increased mortality in the setting of concomitant inflammation.
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Affiliation(s)
- Emanuel Zitt
- Department of Nephrology and Dialysis, Feldkirch Academic Teaching Hospital, Feldkirch, Austria
- Vorarlberg Institute for Vascular Investigation and Treatment (VIVIT), Feldkirch, Austria
| | - Gisela Sturm
- Department of Dermatology and Venereology, Innsbruck Medical University, Innsbruck, Austria
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Florian Kronenberg
- Division of Genetic Epidemiology, Department of Medical Genetics, Molecular and Clinical Pharmacology, Innsbruck Medical University, Innsbruck, Austria
| | - Ulrich Neyer
- Vorarlberg Institute for Vascular Investigation and Treatment (VIVIT), Feldkirch, Austria
| | - Florian Knoll
- Department of Nephrology and Dialysis, Feldkirch Academic Teaching Hospital, Feldkirch, Austria
| | - Karl Lhotta
- Department of Nephrology and Dialysis, Feldkirch Academic Teaching Hospital, Feldkirch, Austria
- Vorarlberg Institute for Vascular Investigation and Treatment (VIVIT), Feldkirch, Austria
- * E-mail: (KL); (GW)
| | - Günter Weiss
- Department of Internal Medicine VI (Infectious Diseases, Immunology, Rheumatology, Pneumology), Innsbruck Medical University, Innsbruck, Austria
- * E-mail: (KL); (GW)
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192
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Muraille E, Leo O, Moser M. TH1/TH2 paradigm extended: macrophage polarization as an unappreciated pathogen-driven escape mechanism? Front Immunol 2014; 5:603. [PMID: 25505468 PMCID: PMC4244692 DOI: 10.3389/fimmu.2014.00603] [Citation(s) in RCA: 200] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2014] [Accepted: 11/10/2014] [Indexed: 02/04/2023] Open
Abstract
The classical view of the Th1/Th2 paradigm posits that the pathogen nature, infectious cycle, and persistence represent key parameters controlling the choice of effector mechanisms operating during an immune response. Thus, efficient Th1 responses are triggered by replicating intracellular pathogens, while Th2 responses would control helminth infection and promote tissue repair during the resolution phase of an infectious event. However, this vision does not account for a growing body of data describing how pathogens exploit the polarization of the host immune response to their own benefit. Recently, the study of macrophages has illustrated a novel aspect of this arm race between pathogens and the immune system, and the central role of macrophages in homeostasis, repair and defense of all tissues is now fully appreciated. Like T lymphocytes, macrophages differentiate into distinct effectors including classically (M1) and alternatively (M2) activated macrophages. Interestingly, in addition to represent immune effectors, M1/M2 cells have been shown to represent potential reservoir cells to a wide range of intracellular pathogens. Subversion of macrophage cell metabolism by microbes appears as a recently uncovered immune escape strategy. Upon infection, several microbial agents have been shown to activate host metabolic pathways leading to the production of nutrients necessary to their long-term persistence in host. The purpose of this review is to summarize and discuss the strategies employed by pathogens to manipulate macrophage differentiation, and in particular their basic cell metabolism, to favor their own growth while avoiding immune control.
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Affiliation(s)
- Eric Muraille
- Laboratory of Parasitology, Faculty of Medicine, Université Libre de Bruxelles , Brussels , Belgium
| | - Oberdan Leo
- Laboratory of Immunobiology, Faculty of Sciences, Université Libre de Bruxelles , Gosselies , Belgium
| | - Muriel Moser
- Laboratory of Immunobiology, Faculty of Sciences, Université Libre de Bruxelles , Gosselies , Belgium
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193
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The Vibrio cholerae Cpx envelope stress response senses and mediates adaptation to low iron. J Bacteriol 2014; 197:262-76. [PMID: 25368298 DOI: 10.1128/jb.01957-14] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Cpx pathway, a two-component system that employs the sensor histidine kinase CpxA and the response regulator CpxR, regulates crucial envelope stress responses across bacterial species and affects antibiotic resistance. To characterize the CpxR regulon in Vibrio cholerae, the transcriptional profile of the pandemic V. cholerae El Tor C6706 strain was examined upon overexpression of cpxR. Our data show that the Cpx regulon of V. cholerae is enriched in genes encoding membrane-localized and transport proteins, including a large number of genes known or predicted to be iron regulated. Activation of the Cpx pathway further led to the expression of TolC, the major outer membrane pore, and of components of two RND efflux systems in V. cholerae. We show that iron chelation, toxic compounds, or deletion of specific RND efflux components leads to Cpx pathway activation. Furthermore, mutations that eliminate the Cpx response or members of its regulon result in growth phenotypes in the presence of these inducers that, together with Cpx pathway activation, are partially suppressed by iron. Cumulatively, our results suggest that a major function of the Cpx response in V. cholerae is to mediate adaptation to envelope perturbations caused by toxic compounds and the depletion of iron.
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194
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Inflammation-associated adherent-invasive Escherichia coli are enriched in pathways for use of propanediol and iron and M-cell translocation. Inflamm Bowel Dis 2014; 20:1919-32. [PMID: 25230163 DOI: 10.1097/mib.0000000000000183] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
BACKGROUND Perturbations of the intestinal microbiome, termed dysbiosis, are linked to intestinal inflammation. Isolation of adherent-invasive Escherichia coli (AIEC) from intestines of patients with Crohn's disease (CD), dogs with granulomatous colitis, and mice with acute ileitis suggests these bacteria share pathoadaptive virulence factors that promote inflammation. METHODS To identify genes associated with AIEC, we sequenced the genomes of phylogenetically diverse AIEC strains isolated from people with CD (4), dogs with granulomatous colitis (2), and mice with ileitis (2) and 1 non-AIEC strain from CD ileum and compared them with 38 genome sequences of E. coli and Shigella. We then determined the prevalence of AIEC-associated genes in 49 E. coli strains from patients with CD and controls and correlated genotype with invasion of intestinal epithelial cells, persistence within macrophages, AIEC pathotype, and growth in standardized conditions. RESULTS Genes encoding propanediol utilization (pdu operon) and iron acquisition (yersiniabactin, chu operon) were overrepresented in AIEC relative to nonpathogenic E. coli. PduC (propanediol dehydratase) was enriched in CD-derived AIEC, correlated with increased cellular invasion, and persistence in vitro and was increasingly expressed in fucose-containing media. Growth of AIEC required iron, and the presence of chuA (heme acquisition) correlated with persistence in macrophages. CD-associated AIEC with lpfA 154 (long polar fimbriae) demonstrated increased invasion of epithelial cells and translocation across M cells. CONCLUSIONS Our findings provide novel insights into the genetic basis of the AIEC pathotype, supporting the concept that AIEC are equipped to exploit and promote intestinal inflammation and reveal potential targets for intervention against AIEC and inflammation-associated dysbiosis.
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195
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Beck KL, Conlon CA, Kruger R, Coad J. Dietary determinants of and possible solutions to iron deficiency for young women living in industrialized countries: a review. Nutrients 2014; 6:3747-76. [PMID: 25244367 PMCID: PMC4179187 DOI: 10.3390/nu6093747] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Revised: 08/22/2014] [Accepted: 08/25/2014] [Indexed: 12/21/2022] Open
Abstract
Iron deficiency is a concern in both developing and developed (industrialized) countries; and young women are particularly vulnerable. This review investigates dietary determinants of and possible solutions to iron deficiency in young women living in industrialized countries. Dietary factors including ascorbic acid and an elusive factor in animal protein foods (meat; fish and poultry) enhance iron absorption; while phytic acid; soy protein; calcium and polyphenols inhibit iron absorption. However; the effects of these dietary factors on iron absorption do not necessarily translate into an association with iron status and iron stores (serum ferritin concentration). In cross-sectional studies; only meat intake has consistently (positively) been associated with higher serum ferritin concentrations. The enhancing effects of ascorbic acid and meat on iron absorption may be negated by the simultaneous consumption of foods and nutrients which are inhibitory. Recent cross-sectional studies have considered the combination and timing of foods consumed; with mixed results. Dietary interventions using a range of focused dietary measures to improve iron status appear to be more effective than dietary approaches that focus on single nutrients or foods. Further research is needed to determine optimal dietary recommendations for both the prevention and treatment of iron deficiency.
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Affiliation(s)
- Kathryn L Beck
- Institute of Food Nutrition and Human Health, College of Health, Massey University, Private Bag 102 904, North Shore City 0745, New Zealand.
| | - Cathryn A Conlon
- Institute of Food Nutrition and Human Health, College of Health, Massey University, Private Bag 102 904, North Shore City 0745, New Zealand.
| | - Rozanne Kruger
- Institute of Food Nutrition and Human Health, College of Health, Massey University, Private Bag 102 904, North Shore City 0745, New Zealand.
| | - Jane Coad
- Institute of Food Nutrition and Human Health, College of Health, Massey University, Private Bag 102 904, North Shore City 0745, New Zealand.
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196
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Nairz M, Schroll A, Demetz E, Tancevski I, Theurl I, Weiss G. 'Ride on the ferrous wheel'--the cycle of iron in macrophages in health and disease. Immunobiology 2014; 220:280-94. [PMID: 25240631 DOI: 10.1016/j.imbio.2014.09.010] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 08/20/2014] [Accepted: 09/05/2014] [Indexed: 12/16/2022]
Abstract
Iron homeostasis and macrophage biology are closely interconnected. On the one hand, iron exerts multiple effects on macrophage polarization and functionality. On the other hand, macrophages are central for mammalian iron homeostasis. The phagocytosis of senescent erythrocytes and their degradation by macrophages enable efficient recycling of iron and the maintenance of systemic iron balance. Macrophages express multiple molecules and proteins for the acquisition and utilization of iron and many of these pathways are affected by inflammatory signals. Of note, iron availability within macrophages has significant effects on immune effector functions and metabolic pathways within these cells. This review summarizes the physiological and pathophysiological aspects of macrophage iron metabolism and highlights its relevant consequences on immune function and in common diseases such as infection and atherosclerosis.
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Affiliation(s)
- Manfred Nairz
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria.
| | - Andrea Schroll
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Egon Demetz
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Ivan Tancevski
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Igor Theurl
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine VI, Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck, Austria.
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197
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Jung M, Mertens C, Brüne B. Macrophage iron homeostasis and polarization in the context of cancer. Immunobiology 2014; 220:295-304. [PMID: 25260218 DOI: 10.1016/j.imbio.2014.09.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2014] [Revised: 08/07/2014] [Accepted: 09/05/2014] [Indexed: 12/28/2022]
Abstract
Macrophages are central in regulating iron homeostasis, which is tightly linked to their versatile role during innate immunity. They sequester iron by phagocytosis of senescent erythrocytes and represent a major source of available iron in the body. Macrophage iron homeostasis is coupled to the functional heterogeneity and plasticity of these cells, with their extreme roles during inflammation, immune modulation, and resolution of inflammation. It is now appreciated that the macrophage polarization process dictates expression profiles of genes involved in iron metabolism. Therefore, macrophages have evolved a multitude of mechanisms to sequester, transport, store, and release iron. A new, enigmatic protein entering the iron scene and affecting the macrophage phenotype is lipocalin-2. Iron sequestration in macrophages depletes the microenvironment, thereby limiting extracellular pathogen or tumor growth, while fostering inflammation. In contrast, iron release from macrophages contributes to bystander cell proliferation, which is important for tissue regeneration and repair. This dichotomy is also reflected by the dual role of lipocalin-2 in macrophages. Unfortunately, the iron release macrophage phenotype is also a characteristic of tumor-associated macrophages and stimulates tumor cell survival and growth. Iron sequestration versus its release is now appreciated to be associated with the macrophage polarization program and can be used to explain a number of biological functions attributed to distinct macrophage phenotypes. Here we discuss macrophage iron homeostasis with a special focus on lipocalin-2 related to the formation and function of tumor-associated macrophages.
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Affiliation(s)
- Michaela Jung
- Institute of Biochemistry I/ZAFES, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany
| | - Christina Mertens
- Institute of Biochemistry I/ZAFES, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany
| | - Bernhard Brüne
- Institute of Biochemistry I/ZAFES, Faculty of Medicine, Goethe-University Frankfurt, 60590 Frankfurt, Germany.
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198
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Soares MP, Gozzelino R, Weis S. Tissue damage control in disease tolerance. Trends Immunol 2014; 35:483-94. [PMID: 25182198 DOI: 10.1016/j.it.2014.08.001] [Citation(s) in RCA: 132] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2014] [Revised: 08/09/2014] [Accepted: 08/11/2014] [Indexed: 02/07/2023]
Abstract
Immune-driven resistance mechanisms are the prevailing host defense strategy against infection. By contrast, disease tolerance mechanisms limit disease severity by preventing tissue damage or ameliorating tissue function without interfering with pathogen load. We propose here that tissue damage control underlies many of the protective effects of disease tolerance. We explore the mechanisms of cellular adaptation that underlie tissue damage control in response to infection as well as sterile inflammation, integrating both stress and damage responses. Finally, we discuss the potential impact of targeting these mechanisms in the treatment of disease.
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199
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Lee JH, Pooley NJ, Mohd-Adnan A, Martin SAM. Cloning and characterisation of multiple ferritin isoforms in the Atlantic salmon (Salmo salar). PLoS One 2014; 9:e103729. [PMID: 25078784 PMCID: PMC4117605 DOI: 10.1371/journal.pone.0103729] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 07/06/2014] [Indexed: 12/21/2022] Open
Abstract
Ferritin is a highly-conserved iron-storage protein that has also been identified as an acute phase protein within the innate immune system. The iron-storage function is mediated through complementary roles played by heavy (H)-chain subunit as well as the light (L) in mammals or middle (M)-chain in teleosts, respectively. In this study, we report the identification of five ferritin subunits (H1, H2, M1, M2, M3) in the Atlantic salmon that were supported by the presence of iron-regulatory regions, gene structure, conserved domains and phylogenetic analysis. Tissue distribution analysis across eight different tissues showed that each of these isoforms is differentially expressed. We also examined the expression of the ferritin isoforms in the liver and kidney of juvenile Atlantic salmon that was challenged with Aeromonas salmonicida as well as in muscle cell culture stimulated with interleukin-1β. We found that each isoform displayed unique expression profiles, and in certain conditions the expressions between the isoforms were completely diametrical to each other. Our study is the first report of multiple ferritin isoforms from both the H- and M-chains in a vertebrate species, as well as ferritin isoforms that showed decreased expression in response to infection. Taken together, the results of our study suggest the possibility of functional differences between the H- and M-chain isoforms in terms of tissue localisation, transcriptional response to bacterial exposure and stimulation by specific immune factors.
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Affiliation(s)
- Jun-Hoe Lee
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
- School of Biosciences and Biotechnology, Faculty of Science & Technology, University of Kebangsaan, Selangor, Malaysia
| | - Nicholas J. Pooley
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
| | - Adura Mohd-Adnan
- School of Biosciences and Biotechnology, Faculty of Science & Technology, University of Kebangsaan, Selangor, Malaysia
- Malaysia Genome Institute, Ministry of Science, Technology and Innovation, Selangor, Malaysia
| | - Samuel A. M. Martin
- Institute of Biological and Environmental Sciences, University of Aberdeen, Aberdeen, United Kingdom
- * E-mail:
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200
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Nairz M, Haschka D, Demetz E, Weiss G. Iron at the interface of immunity and infection. Front Pharmacol 2014; 5:152. [PMID: 25076907 PMCID: PMC4100575 DOI: 10.3389/fphar.2014.00152] [Citation(s) in RCA: 209] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Accepted: 06/10/2014] [Indexed: 12/18/2022] Open
Abstract
Both, mammalian cells and microbes have an essential need for iron, which is required for many metabolic processes and for microbial pathogenicity. In addition, cross-regulatory interactions between iron homeostasis and immune function are evident. Cytokines and the acute phase protein hepcidin affect iron homeostasis leading to the retention of the metal within macrophages and hypoferremia. This is considered to result from a defense mechanism of the body to limit the availability of iron for extracellular pathogens while on the other hand the reduction of circulating iron results in the development of anemia of inflammation. Opposite, iron and the erythropoiesis inducing hormone erythropoietin affect innate immune responses by influencing interferon-gamma (IFN-γ) mediated (iron) or NF-kB inducible (erythropoietin) immune effector pathways in macrophages. Thus, macrophages loaded with iron lose their ability to kill intracellular pathogens via IFN-γ mediated effector pathways such as nitric oxide (NO) formation. Accordingly, macrophages invaded by the intracellular bacterium Salmonella enterica serovar Typhimurium increase the expression of the iron export protein ferroportin thereby reducing the availability of iron for intramacrophage bacteria while on the other side strengthening anti-microbial macrophage effector pathways via increased formation of NO or TNF-α. In addition, certain innate resistance genes such as natural resistance associated macrophage protein function (Nramp1) or lipocalin-2 exert part of their antimicrobial activity by controlling host and/or microbial iron homeostasis. Consequently, pharmacological or dietary modification of cellular iron trafficking enhances host resistance to intracellular pathogens but may increase susceptibility to microbes in the extracellular compartment and vice versa. Thus, the control over iron homeostasis is a central battlefield in host–pathogen interplay influencing the course of an infectious disease in favor of either the mammalian host or the pathogenic invader.
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Affiliation(s)
- Manfred Nairz
- Department of Internal Medicine VI-Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck Innsbruck, Austria
| | - David Haschka
- Department of Internal Medicine VI-Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck Innsbruck, Austria
| | - Egon Demetz
- Department of Internal Medicine VI-Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck Innsbruck, Austria
| | - Günter Weiss
- Department of Internal Medicine VI-Infectious Diseases, Immunology, Rheumatology, Pneumology, Medical University of Innsbruck Innsbruck, Austria
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