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Loveridge KM, Sigala PA. Identification of a divalent metal transporter required for cellular iron metabolism in malaria parasites. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.10.587216. [PMID: 38798484 PMCID: PMC11118319 DOI: 10.1101/2024.05.10.587216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Plasmodium falciparum malaria parasites invade and multiply inside red blood cells (RBCs), the most iron-rich compartment in humans. Like all cells, P. falciparum requires nutritional iron to support essential metabolic pathways, but the critical mechanisms of iron acquisition and trafficking during RBC infection have remained obscure. Parasites internalize and liberate massive amounts of heme during large-scale digestion of RBC hemoglobin within an acidic food vacuole (FV) but lack a heme oxygenase to release porphyrin-bound iron. Although most FV heme is sequestered into inert hemozoin crystals, prior studies indicate that trace heme escapes biomineralization and is susceptible to non-enzymatic degradation within the oxidizing FV environment to release labile iron. Parasites retain a homolog of divalent metal transporter 1 (DMT1), a known mammalian iron transporter, but its role in P. falciparum iron acquisition has not been tested. Our phylogenetic studies indicate that P. falciparum DMT1 (PfDMT1) retains conserved molecular features critical for metal transport. We localized this protein to the FV membrane and defined its orientation in an export-competent topology. Conditional knockdown of PfDMT1 expression is lethal to parasites, which display broad cellular defects in iron-dependent functions, including impaired apicoplast biogenesis and mitochondrial polarization. Parasites are selectively rescued from partial PfDMT1 knockdown by supplementation with exogenous iron, but not other metals. These results support a cellular paradigm whereby PfDMT1 is the molecular gatekeeper to essential iron acquisition by blood-stage malaria parasites and suggest that therapeutic targeting of PfDMT1 may be a potent antimalarial strategy.
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Prabhakar PK. Bacterial Siderophores and Their Potential Applications: A Review. Curr Mol Pharmacol 2021; 13:295-305. [PMID: 32418535 DOI: 10.2174/1874467213666200518094445] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Revised: 04/15/2020] [Accepted: 04/23/2020] [Indexed: 12/16/2022]
Abstract
The bacterial infection is one of the major health issues throughout the world. To protect humans from the infection and infectious agents, it is important to understand the mechanism of interaction of pathogens along with their susceptible hosts. This will help us to develop a novel strategy for designing effective new drugs or vaccines. As iron is an essential metal ion required for all the living systems for their growth, as well, it is needed by pathogenic bacterial cells for their growth and development inside host tissues. To get iron from the host tissues, microbes developed an iron-chelating system called siderophore and also corresponding receptors. Siderophores are low molecular weight organic complex produced by different strains of bacteria for the procurement of iron from the environment or host body under the iron deficient-conditions. Mostly in the environment at physiological pH, the iron is present in the ferric ionic form (Fe3+), which is water- insoluble and thus inaccessible for them. Such a condition promotes the generation of siderophores. These siderophores have been used in different areas such as agriculture, treatment of diseases, culture the unculturable strains of bacteria, promotion of plant growth, controlling phytopathogens, detoxification of heavy metal contamination, etc. In the medical field, siderophores can be used as "Trojan Horse Strategy", which forms a complex with antibiotics and also delivers these antibiotics to the desired locations, especially in antibiotic-resistant bacteria. The promising application of siderophore-based use of antibiotics for the management of bacterial resistance can be strategies to be used.
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Affiliation(s)
- Pranav Kumar Prabhakar
- Department of Transdisciplinary Research, Lovely Professional University, Phagwara, Punjab-144411, India
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Fan D, Fang Q. Siderophores for medical applications: Imaging, sensors, and therapeutics. Int J Pharm 2021; 597:120306. [PMID: 33540031 DOI: 10.1016/j.ijpharm.2021.120306] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2020] [Revised: 01/19/2021] [Accepted: 01/20/2021] [Indexed: 01/07/2023]
Abstract
Siderophores are low-molecular-weight chelators produced by microorganisms to scavenge iron from the environment and deliver it to cells via specific receptors. Tremendous researches on the molecular basis of siderophore regulation, synthesis, secretion, and uptake have inspired their diverse applications in the medical field. Replacing iron with radionuclides in siderophores, such as the most prominent Ga-68 for positron emission tomography (PET), carves out ways for targeted imaging of infectious diseases and cancers. Additionally, the high affinity of siderophores for metal ions or microorganisms makes them a potent detecting moiety in sensors that can be used for diagnosis. As for therapeutics, the notable Trojan horse-inspired siderophore-antibiotic conjugates demonstrate enhanced toxicity against multi-drug resistant (MDR) pathogens. Besides, siderophores can tackle iron overload diseases and, when combined with moieties such as hydrogels and nanoparticles, a wide spectrum of iron-induced diseases and even cancers. In this review, we briefly outline the related mechanisms, before summarizing the siderophore-based applications in imaging, sensors, and therapeutics.
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Affiliation(s)
- Di Fan
- Laboratory of Theoretical and Computational Nanoscience, CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, PR China
| | - Qiaojun Fang
- Laboratory of Theoretical and Computational Nanoscience, CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Center for Excellence in Nanoscience, Beijing Key Laboratory of Ambient Particles Health Effects and Prevention Techniques, National Center for Nanoscience and Technology, Chinese Academy of Sciences, Beijing 100190, PR China; University of Chinese Academy of Sciences, No. 19A Yuquan Road, Beijing 100049, PR China; Sino-Danish Center for Education and Research, Beijing 101408, PR China.
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Detection and Characterization of Antibacterial Siderophores Secreted by Endophytic Fungi from Cymbidium aloifolium. Biomolecules 2020; 10:biom10101412. [PMID: 33036284 PMCID: PMC7600725 DOI: 10.3390/biom10101412] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/15/2020] [Accepted: 06/18/2020] [Indexed: 11/28/2022] Open
Abstract
Endophytic fungi from orchid plants are reported to secrete secondary metabolites which include bioactive antimicrobial siderophores. In this study endophytic fungi capable of secreting siderophores were isolated from Cymbidium aloifolium, a medicinal orchid plant. The isolated extracellular siderophores from orchidaceous fungi act as chelating agents forming soluble complexes with Fe3+. The 60% endophytic fungi of Cymbidium aloifolium produced hydroxamate siderophore on CAS agar. The highest siderophore percentage was 57% in Penicillium chrysogenum (CAL1), 49% in Aspergillus sydowii (CAR12), 46% in Aspergillus terreus (CAR14) by CAS liquid assay. The optimum culture parameters for siderophore production were 30 °C, pH 6.5, maltose and ammonium nitrate and the highest resulting siderophore content was 73% in P. chrysogenum. The total protein content of solvent-purified siderophore increased four-fold compared with crude filtrate. The percent Fe3+ scavenged was detected by atomic absorption spectra analysis and the highest scavenging value was 83% by P. chrysogenum. Thin layer chromatography of purified P. chrysogenum siderophore showed a wine-colored spot with Rf value of 0.54. HPLC peaks with Rts of 10.5 and 12.5 min were obtained for iron-free and iron-bound P. chrysogenum siderophore, respectively. The iron-free P. chrysogenum siderophore revealed an exact mass-to-charge ratio (m/z) of 400.46 and iron-bound P. chrysogenum siderophore revealed a m/z of 453.35. The solvent-extracted siderophores inhibited the virulent plant pathogens Ralstonia solanacearum, that causes bacterial wilt in groundnut and Xanthomonas oryzae pv. oryzae which causes bacterial blight disease in rice. Thus, bioactive siderophore-producing endophytic P. chrysogenum can be exploited in the form of formulations for development of resistance against other phytopathogens in crop plants.
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Hoffmann KM, Goncuian ES, Karimi KL, Amendola CR, Mojab Y, Wood KM, Prussia GA, Nix J, Yamamoto M, Lathan K, Orion IW. Cofactor Complexes of DesD, a Model Enzyme in the Virulence-related NIS Synthetase Family. Biochemistry 2020; 59:3427-3437. [PMID: 32885650 DOI: 10.1021/acs.biochem.9b00899] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The understudied nonribosomal-peptide-synthetase-independent siderophore (NIS) synthetase family has been increasingly associated with virulence in bacterial species due to its key role in the synthesis of hydroxamate and carboxylate "stealth" siderophores. We have identified a model family member, DesD, from Streptomyces coelicolor, to structurally characterize using a combination of a wild-type and a Arg306Gln variant in apo, cofactor product AMP-bound, and cofactor reactant ATP-bound complexes. The kinetics in the family has been limited by solubility and reporter assays, so we have developed a label-free kinetics assay utilizing a single-injection isothermal-titration-calorimetry-based method. We report second-order rate constants that are 50 times higher than the previous estimations for DesD. Our Arg306Gln DesD variant was also tested under identical buffer and substrate conditions, and its undetectable activity was confirmed. These are the first reported structures for DesD, and they describe the critical cofactor coordination. This is also the first label-free assay to unambiguously determine the kinetics for an NIS synthetase.
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Affiliation(s)
- Katherine M Hoffmann
- Department of Chemistry, California Lutheran University, 60 West Olsen Road #3700, Thousand Oaks, California 91360, United States
| | - Eliana S Goncuian
- Department of Chemistry, California Lutheran University, 60 West Olsen Road #3700, Thousand Oaks, California 91360, United States
| | - Kimya L Karimi
- Department of Chemistry, California Lutheran University, 60 West Olsen Road #3700, Thousand Oaks, California 91360, United States
| | - Caroline R Amendola
- Department of Chemistry and Biochemistry, Gonzaga University, 502 East Boone Avenue, Spokane, Washington 99258, United States
| | - Yasi Mojab
- Department of Chemistry, California Lutheran University, 60 West Olsen Road #3700, Thousand Oaks, California 91360, United States
| | - Kaitlin M Wood
- Department of Chemistry and Biochemistry, Gonzaga University, 502 East Boone Avenue, Spokane, Washington 99258, United States
| | - Gregory A Prussia
- Department of Chemistry and Biochemistry, Gonzaga University, 502 East Boone Avenue, Spokane, Washington 99258, United States
| | - Jay Nix
- Advanced Light Source, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, United States
| | - Margaret Yamamoto
- Department of Chemistry and Biochemistry, Gonzaga University, 502 East Boone Avenue, Spokane, Washington 99258, United States
| | - Kiera Lathan
- Department of Chemistry, California Lutheran University, 60 West Olsen Road #3700, Thousand Oaks, California 91360, United States
| | - Iris W Orion
- Department of Chemistry and Biochemistry, Gonzaga University, 502 East Boone Avenue, Spokane, Washington 99258, United States
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Heller LE, Goggins E, Roepe PD. Dihydroartemisinin-Ferriprotoporphyrin IX Adduct Abundance in Plasmodium falciparum Malarial Parasites and the Relationship to Emerging Artemisinin Resistance. Biochemistry 2018; 57:6935-6945. [PMID: 30512926 DOI: 10.1021/acs.biochem.8b00960] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Previously (Heller, L. E., and Roepe, P. D. Quantification of Free Ferriprotoporphyrin IX Heme and Hemozoin for Artemisinin Sensitive versus Delayed Clearance Phenotype Plasmodium falciparum Malarial Parasites. Biochemistry, DOI: 10.1021/acs.biochem.8b00959, preceding paper in this issue), we quantified free ferriprotoporphyrin IX (FPIX) heme abundance for control versus delayed clearance phenotype (DCP) intraerythrocytic Plasmodium falciparum malarial parasites. Because artemisinin drugs are activated by free FPIX, these data predict that the abundance of long-hypothesized toxic artemisinin drug-FPIX covalent adducts might differ for control versus DCP parasites. If so, this would have important repercussions for understanding the mechanism of the DCP, also known as emerging artemisinin resistance. To test these predictions, we studied in vitro formation of FPIX-dihydroartemisinin (DHA) adducts and then for the first time quantified the abundance of FPIX-DHA adducts formed within live P. falciparum versus the stage of intraerythrocytic development. Using matched isogenic parasite strains, we quantified the adduct for DCP versus control parasite strains and found that mutant PfK13 mediates lower adduct abundance for DCP parasites. The results suggest improved models for the molecular pharmacology of artemisinin-based antimalarial drugs and the molecular mechanism of the DCP.
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Affiliation(s)
- Laura E Heller
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology , Georgetown University , 37th and O Streets Northwest , Washington, D.C. 20057 , United States
| | - Eibhlin Goggins
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology , Georgetown University , 37th and O Streets Northwest , Washington, D.C. 20057 , United States
| | - Paul D Roepe
- Department of Chemistry and Department of Biochemistry and Cellular and Molecular Biology , Georgetown University , 37th and O Streets Northwest , Washington, D.C. 20057 , United States
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7
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Lewandowska H, Stępkowski TM, Męczyńska-Wielgosz S, Sikorska K, Sadło J, Dudek J, Kruszewski M. LDL dinitrosyl iron complex acts as an iron donor in mouse macrophages. J Inorg Biochem 2018; 188:29-37. [PMID: 30119015 DOI: 10.1016/j.jinorgbio.2018.08.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 07/22/2018] [Accepted: 08/02/2018] [Indexed: 12/27/2022]
Abstract
[Fe(NO)2] - modified nanoparticles of low-density protein (DNICLDL) can serve as conveyors of iron in the form of stable complexes with ApoB100 protein. As reported recently, in human hepatoma cells DNICLDL significantly increased the total iron content, while showing low toxicity. In the present work, we focused on the effects of internalization of DNIC-modified lipoproteins in macrophages, with special regards to cytotoxicity. DNICLDL was administered to a model macrophage cell line, RAW 264.7. Administration of DNICLDL considerably increased total iron content. High increase of iron was accompanied by moderate toxicity. As shown by in vitro plasmid nicking assay, chelation of iron in the form of DNIC strongly reduced the iron-related reactive oxygen species (ROS) -induced DNA damage. In addition, DNICLDL, plausibly due to its NO-donating activity, did not induce inducible nitric oxide synthase (iNOS) expression, as opposed to other forms of low-density protein (LDL).
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Affiliation(s)
- Hanna Lewandowska
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland.
| | - Tomasz M Stępkowski
- Laboratory of Mitochondrial Biogenesis, Centre of New Technologies UW, Banacha 2c, 02-097 Warsaw, Poland
| | | | - Katarzyna Sikorska
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland
| | - Jarosław Sadło
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland
| | - Jakub Dudek
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland
| | - Marcin Kruszewski
- Institute of Nuclear Chemistry and Technology, 16 Dorodna Str., 03-195 Warsaw, Poland; Faculty of Medicine, University of Information Technology and Management in Rzeszów, ul. Sucharskiego 2, 35-225 Rzeszów, Poland; Department of Molecular Biology and Translational Research, Institute of Rural Health, Jaczewskiego 2, 20-090 Lublin, Poland
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Saha M, Sarkar S, Sarkar B, Sharma BK, Bhattacharjee S, Tribedi P. Microbial siderophores and their potential applications: a review. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:3984-99. [PMID: 25758420 DOI: 10.1007/s11356-015-4294-0] [Citation(s) in RCA: 298] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Accepted: 02/27/2015] [Indexed: 05/18/2023]
Abstract
Siderophores are small organic molecules produced by microorganisms under iron-limiting conditions which enhance the uptake of iron to the microorganisms. In environment, the ferric form of iron is insoluble and inaccessible at physiological pH (7.35-7.40). Under this condition, microorganisms synthesize siderophores which have high affinity for ferric iron. These ferric iron-siderophore complexes are then transported to cytosol. In cytosol, the ferric iron gets reduced into ferrous iron and becomes accessible to microorganism. In recent times, siderophores have drawn much attention due to its potential roles in different fields. Siderophores have application in microbial ecology to enhance the growth of several unculturable microorganisms and can alter the microbial communities. In the field of agriculture, different types of siderophores promote the growth of several plant species and increase their yield by enhancing the Fe uptake to plants. Siderophores acts as a potential biocontrol agent against harmful phyto-pathogens and holds the ability to substitute hazardous pesticides. Heavy-metal-contaminated samples can be detoxified by applying siderophores, which explicate its role in bioremediation. Siderophores can detect the iron content in different environments, exhibiting its role as a biosensor. In the medical field, siderophore uses the "Trojan horse strategy" to form complexes with antibiotics and helps in the selective delivery of antibiotics to the antibiotic-resistant bacteria. Certain iron overload diseases for example sickle cell anemia can be treated with the help of siderophores. Other medical applications of siderophores include antimalarial activity, removal of transuranic elements from the body, and anticancer activity. The aim of this review is to discuss the important roles and applications of siderophores in different sectors including ecology, agriculture, bioremediation, biosensor, and medicine.
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Affiliation(s)
- Maumita Saha
- Department of Molecular Biology & Bioinformatics, Tripura University (A Central University), Suryamaninagar, Tripura, 799022, India
| | - Subhasis Sarkar
- Department of Molecular Biology & Bioinformatics, Tripura University (A Central University), Suryamaninagar, Tripura, 799022, India
| | - Biplab Sarkar
- National Institute of Abiotic Stress Management, Baramati, 413115, Pune, Maharashtra, India
| | - Bipin Kumar Sharma
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Tripura, 799022, India
| | - Surajit Bhattacharjee
- Department of Molecular Biology & Bioinformatics, Tripura University (A Central University), Suryamaninagar, Tripura, 799022, India.
| | - Prosun Tribedi
- Department of Microbiology, Tripura University (A Central University), Suryamaninagar, Tripura, 799022, India.
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Slavic K, Krishna S, Lahree A, Bouyer G, Hanson KK, Vera I, Pittman JK, Staines HM, Mota MM. A vacuolar iron-transporter homologue acts as a detoxifier in Plasmodium. Nat Commun 2016; 7:10403. [PMID: 26786069 PMCID: PMC4735874 DOI: 10.1038/ncomms10403] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 12/07/2015] [Indexed: 01/03/2023] Open
Abstract
Iron is an essential micronutrient but is also highly toxic. In yeast and plant cells, a key detoxifying mechanism involves iron sequestration into intracellular storage compartments, mediated by members of the vacuolar iron-transporter (VIT) family of proteins. Here we study the VIT homologue from the malaria parasites Plasmodium falciparum (PfVIT) and Plasmodium berghei (PbVIT). PfVIT-mediated iron transport in a yeast heterologous expression system is saturable (Km ∼ 14.7 μM), and selective for Fe(2+) over other divalent cations. PbVIT-deficient P. berghei lines (Pbvit(-)) show a reduction in parasite load in both liver and blood stages of infection in mice. Moreover, Pbvit(-) parasites have higher levels of labile iron in blood stages and are more sensitive to increased iron levels in liver stages, when compared with wild-type parasites. Our data are consistent with Plasmodium VITs playing a major role in iron detoxification and, thus, normal development of malaria parasites in their mammalian host.
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Affiliation(s)
- Ksenija Slavic
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Sanjeev Krishna
- Institute for Infection & Immunity, St. George's, University of London, London SW17 0RE, UK
| | - Aparajita Lahree
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Guillaume Bouyer
- Institute for Infection & Immunity, St. George's, University of London, London SW17 0RE, UK
- Sorbonne Universités, UPMC Univ Paris 6, CNRS, UMR 8227, Comparative Physiology of Erythrocytes, Station Biologique de Roscoff, CS 90074, 29688 Roscoff, France
| | - Kirsten K. Hanson
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, 1649-028 Lisbon, Portugal
- Present address: University of Texas at San Antonio, Department of Biology and STCEID, San Antonio, Texas 78249, USA
| | - Iset Vera
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, 1649-028 Lisbon, Portugal
| | - Jon K. Pittman
- Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Henry M. Staines
- Institute for Infection & Immunity, St. George's, University of London, London SW17 0RE, UK
| | - Maria M. Mota
- Instituto de Medicina Molecular, Faculdade de Medicina Universidade de Lisboa, 1649-028 Lisbon, Portugal
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Antioxidant and antimalarial properties of butein and homobutein based on their ability to chelate iron (II and III) cations: a DFT study in vacuo and in solution. Eur Food Res Technol 2015. [DOI: 10.1007/s00217-015-2520-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Wang W, Qiu Z, Tan H, Cao L. Siderophore production by actinobacteria. Biometals 2014; 27:623-31. [PMID: 24770987 DOI: 10.1007/s10534-014-9739-2] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Accepted: 04/13/2014] [Indexed: 11/25/2022]
Abstract
Produced by bacteria, fungi and plants, siderophores are low-molecular-weight chelating agents (200-2,000 Da) to facilitate uptake of iron (Fe). They play an important role in extracellular Fe solubilization from minerals to make it available to microorganisms. Siderophores have various chemical structures and form a family of at least 500 different compounds. Some antibiotics (i.e., albomycins, ferrimycins, danomycins, salmycins, and tetracyclines) can bind Fe and some siderophores showed diverse biological activities. Functions and applications of siderophores derived from actinobacteria were reviewed to better understand the diverse metabolites.
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Affiliation(s)
- Wenfeng Wang
- School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou, 510275, People's Republic of China
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Walcourt A, Kurantsin-Mills J, Kwagyan J, Adenuga BB, Kalinowski DS, Lovejoy DB, Lane DJR, Richardson DR. Anti-plasmodial activity of aroylhydrazone and thiosemicarbazone iron chelators: effect on erythrocyte membrane integrity, parasite development and the intracellular labile iron pool. J Inorg Biochem 2013; 129:43-51. [PMID: 24028863 PMCID: PMC3838870 DOI: 10.1016/j.jinorgbio.2013.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 08/19/2013] [Accepted: 08/19/2013] [Indexed: 01/10/2023]
Abstract
Iron chelators inhibit the growth of the malaria parasite, Plasmodium falciparum, in culture and in animal and human studies. We previously reported the anti-plasmodial activity of the chelators, 2-hydroxy-1-naphthylaldehyde isonicotinoyl hydrazone (311), 2-hydroxy-1-naphthylaldehyde 4-methyl-3-thiosemicarbazone (N4mT), and 2-hydroxy-1-naphthylaldehyde 4-phenyl-3-thiosemicarbazone (N4pT). In fact, these ligands showed greater growth inhibition of chloroquine-sensitive (3D7) and chloroquine-resistant (7G8) strains of P. falciparum in culture compared to desferrioxamine (DFO). The present study examined the effects of 311, N4mT and N4pT on erythrocyte membrane integrity and asexual parasite development. While the characteristic biconcave disk shape of the erythrocytes was unaffected, the chelators caused very slight hemolysis at IC50 values that inhibited parasite growth. The chelators 311, N4mT and N4pT affected all stages of the intra-erythrocytic development cycle (IDC) of P. falciparum in culture. However, while these ligands primarily affected the ring-stage, DFO inhibited primarily trophozoite and schizont-stages. Ring, trophozoite and schizont-stages of the IDC were inhibited by significantly lower concentrations of 311, N4mT, and N4pT (IC50=4.45±1.70, 10.30±4.40, and 3.64±2.00μM, respectively) than DFO (IC50=23.43±3.40μM). Complexation of 311, N4mT and N4pT with iron reduced their anti-plasmodial activity. Estimation of the intracellular labile iron pool (LIP) in erythrocytes showed that the chelation efficacy of 311, N4mT and N4pT corresponded to their anti-plasmodial activities, suggesting that the LIP may be a potential source of non-heme iron for parasite metabolism within the erythrocyte. This study has implications for malaria chemotherapy that specifically disrupts parasite iron utilization.
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Affiliation(s)
- Asikiya Walcourt
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC, 20059
| | - Joseph Kurantsin-Mills
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC, 20059
- Departments of Medicine, Pharmacology and Physiology, The George Washington University Medical Center, Washington, DC, 20037
| | - John Kwagyan
- Design, Biostatistics & Population Studies, Center for Clinical & Translation Science and Department of Community and Family Medicine, Howard University College of Medicine, Washington, DC,20059
| | | | - Danuta S. Kalinowski
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, New South Wales, 2006 Australia
| | - David B. Lovejoy
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, New South Wales, 2006 Australia
| | - Darius J. R. Lane
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, New South Wales, 2006 Australia
| | - Des R. Richardson
- Molecular Pharmacology and Pathology Program, Department of Pathology and Bosch Institute, Blackburn Building (D06), University of Sydney, Sydney, New South Wales, 2006 Australia
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Esan MO, van Hensbroek MB, Nkhoma E, Musicha C, White SA, ter Kuile FO, Phiri KS. Iron Supplementation in HIV-Infected Malawian Children With Anemia: A Double-Blind, Randomized, Controlled Trial. Clin Infect Dis 2013; 57:1626-34. [DOI: 10.1093/cid/cit528] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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14
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Clark M, Fisher NC, Kasthuri R, Cerami Hand C. Parasite maturation and host serum iron influence the labile iron pool of erythrocyte stage Plasmodium falciparum. Br J Haematol 2013; 161:262-9. [PMID: 23398516 DOI: 10.1111/bjh.12234] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 12/20/2012] [Indexed: 12/30/2022]
Abstract
Iron is a critical and tightly regulated nutrient for both the malaria parasite and its human host. The importance of the relationship between host iron and the parasite has been underscored recently by studies showing that host iron supplementation may increase the risk of falciparum malaria. It is unclear what host iron sources the parasite is able to access. We developed a flow cytometry-based method for measuring the labile iron pool (LIP) of parasitized erythrocytes using the nucleic acid dye STYO 61 and the iron sensitive dye, calcein acetoxymethyl ester (CA-AM). This new approach enabled us to measure the LIP of P. falciparum through the course of its erythrocytic life cycle and in response to the addition of host serum iron sources. We found that the LIP increases as the malaria parasite develops from early ring to late schizont stage, and that the addition of either transferrin or ferric citrate to culture media increases the LIP of trophozoites. Our method for detecting the LIP within malaria parasitized RBCs provides evidence that the parasite is able to access serum iron sources as part of the host vs. parasite arms race for iron.
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Affiliation(s)
- Martha Clark
- Department of Microbiology and Immunology, University of North Carolina-Chapel Hill, Chapel Hill, USA, United States
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15
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Antibacterial activities of iron chelators against common nosocomial pathogens. Antimicrob Agents Chemother 2012; 56:5419-21. [PMID: 22850524 DOI: 10.1128/aac.01197-12] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The activities of iron chelators (deferoxamine, deferiprone, Apo6619, and VK28) were evaluated against type strains of Acinetobacter baumannii, Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, and Escherichia coli. Deferiprone, Apo6619, and VK28 each inhibited growth in standard and RPMI tissue culture medium, while deferoxamine had no effect. Additionally, time-kill assays revealed that VK28 had a bacteriostatic effect against S. aureus. Therefore, these newly developed iron chelators might provide a nontraditional approach for treatment of bacterial infections.
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16
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Antimalarial iron chelator, FBS0701, shows asexual and gametocyte Plasmodium falciparum activity and single oral dose cure in a murine malaria model. PLoS One 2012; 7:e37171. [PMID: 22629364 PMCID: PMC3357340 DOI: 10.1371/journal.pone.0037171] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 04/16/2012] [Indexed: 01/19/2023] Open
Abstract
Iron chelators for the treatment of malaria have proven therapeutic activity in vitro and in vivo in both humans and mice, but their clinical use is limited by the unsuitable absorption and pharmacokinetic properties of the few available iron chelators. FBS0701, (S)3"-(HO)-desazadesferrithiocin-polyether [DADFT-PE], is an oral iron chelator currently in Phase 2 human studies for the treatment of transfusional iron overload. The drug has very favorable absorption and pharmacokinetic properties allowing for once-daily use to deplete circulating free iron with human plasma concentrations in the high µM range. Here we show that FBS0701 has inhibition concentration 50% (IC(50)) of 6 µM for Plasmodium falciparum in contrast to the IC(50) for deferiprone and deferoxamine at 15 and 30 µM respectively. In combination, FBS0701 interfered with artemisinin parasite inhibition and was additive with chloroquine or quinine parasite inhibition. FBS0701 killed early stage P. falciparum gametocytes. In the P. berghei Thompson suppression test, a single dose of 100 mg/kg reduced day three parasitemia and prolonged survival, but did not cure mice. Treatment with a single oral dose of 100 mg/kg one day after infection with 10 million lethal P. yoelii 17XL cured all the mice. Pretreatment of mice with a single oral dose of FBS0701 seven days or one day before resulted in the cure of some mice. Plasma exposures and other pharmacokinetics parameters in mice of the 100 mg/kg dose are similar to a 3 mg/kg dose in humans. In conclusion, FBS0701 demonstrates a single oral dose cure of the lethal P. yoelii model. Significantly, this effect persists after the chelator has cleared from plasma. FBS0701 was demonstrated to remove labile iron from erythrocytes as well as enter erythrocytes to chelate iron. FBS0701 may find clinically utility as monotherapy, a malarial prophylactic or, more likely, in combination with other antimalarials.
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17
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Nagoba B, Vedpathak D. Medical Applications of Siderophores. ELECTRONIC JOURNAL OF GENERAL MEDICINE 2011. [DOI: 10.29333/ejgm/82743] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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18
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Petersen I, Eastman R, Lanzer M. Drug-resistant malaria: molecular mechanisms and implications for public health. FEBS Lett 2011; 585:1551-62. [PMID: 21530510 DOI: 10.1016/j.febslet.2011.04.042] [Citation(s) in RCA: 173] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 04/15/2011] [Accepted: 04/18/2011] [Indexed: 10/18/2022]
Abstract
Resistance to antimalarial drugs has often threatened malaria elimination efforts and historically has led to the short-term resurgence of malaria incidences and deaths. With concentrated malaria eradication efforts currently underway, monitoring drug resistance in clinical settings complemented by in vitro drug susceptibility assays and analysis of resistance markers, becomes critical to the implementation of an effective antimalarial drug policy. Understanding of the factors, which lead to the development and spread of drug resistance, is necessary to design optimal prevention and treatment strategies. This review attempts to summarize the unique factors presented by malarial parasites that lead to the emergence and spread of drug resistance, and gives an overview of known resistance mechanisms to currently used antimalarial drugs.
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Affiliation(s)
- Ines Petersen
- Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Heidelberg, Germany.
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19
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Fakih S, Podinovskaia M, Kong X, Schaible UE, Collins HL, Hider RC. Monitoring intracellular labile iron pools: A novel fluorescent iron(III) sensor as a potential non-invasive diagnosis tool. J Pharm Sci 2009; 98:2212-26. [PMID: 18823046 DOI: 10.1002/jps.21583] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
The physiological and pathophysiological importance of intracellular redox active "labile" iron has created a significant need for improved noninvasive diagnostic tools to reliably monitor iron metabolism in living cells. In this context, fluorescent iron-sensitive chemosensors in combination with digital fluorescence spectroscopic methods have proven to be highly sensitive and indispensable tools to determine cellular iron homeostasis. Recently, application of fluorescent iron sensors has led to the identification of a complex sub-cellular iron compartmentation. Cell organelle-specific iron sensors will significantly contribute to enhance fundamental knowledge of cellular iron trafficking, representing a crucial prerequisite for the future development of therapeutic strategies in iron dysregulatory diseases. Here we present physicochemical characterization and functional investigation of a new 3-hydroxypyridin-4-one based fluorescent iron(III) sensor, exclusively monitoring labile iron pools in the endosomal/lysosomal compartments. In vitro studies of the fluorescein labeled probe were carried out in murine bone marrow derived macrophages. Endosomal/lysosomal accumulation of the probe was revealed by confocal microscopy. Flow cytometry analyses demonstrated high sensitivity of the probe towards exogenous alterations of intracellular iron concentrations as well as in response to the chelation potency of iron chelators, clinically approved for treatment of iron-overload related diseases.
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Affiliation(s)
- Sarah Fakih
- Department of Inorganic Chemistry, Georg-August-University of Göttingen, Tammannstrasse 4, 37077 Göttingen, Germany.
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20
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Abstract
Recent evidence from a large, randomized, controlled trial has suggested that the universal administration of iron to children in malaria-endemic areas is associated with an increase in adverse health outcomes. The purpose of this paper is to summarize the available ecologic and intervention trials related to iron and malaria in children, and to set these against current knowledge of the biology of host-pathogen interactions involving iron metabolism. We conclude that, although not fully consistent, the balance of evidence confirms that administration of iron (usually in combination with folic acid) increases the incidence of malaria when given without prophylaxis and in the absence of universal access to treatment. The mechanisms by which additional iron can benefit the parasite are far from clear. There is evidence to suggest that the apparent detrimental effect of iron supplementation may vary according to levels of antecedent iron status, the presence of hemoglobinopathies and glucose-6-phosphate dehydrogenase (G6PD) deficiency, and other host genetic variants, such as variants in haptoglobin. The effects of malaria on host iron metabolism are also reviewed and reveal that the key cause of malaria-induced anemia is a maldistribution of iron and suppression of erythropoiesis rather than an exacerbation of gross iron deficiency. We tentatively conclude that, if it is to be recommended, universal iron supplementation in malarious areas should only be considered in conjunction with some form of prophylaxis (e.g., intermittent preventive therapy [IPT]) or in the context of good health services with ready access to facilities for malaria diagnosis and treatment. An alternative approach would be to screen for anemia and target supplementation only to anemic children. With regard to treatment, there is good evidence that iron supplementation should be withheld until the treatment schedule is complete, both because iron may inhibit treatment and because the absorption of oral iron is blocked by the inflammatory response.
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Affiliation(s)
- Andrew M Prentice
- MRC International Nutrition Group, London School of Hygiene and Tropical Medicine, London 1IE 7HT, United Kingdom.
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21
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Abstract
The subtle balance between proinflammatory and antiinflammatory cytokines plays an important role in determining the severity of the inflammatory reaction and in the anomalous iron handling associated with infection. Conversely, iron deficiency per se appears to limit the severity of the inflammatory response. All of these considerations are at present highly speculative and in need of further experimental and epidemiologic support. If confirmed, the beneficial biological effects of iron depletion may have a defensive role in inflammation and may be perturbed by the nonselective administration of iron to iron-replete patients who would not benefit from such treatment in the first place. In view of the importance of non-transferrin-bound plasma iron (NTBI) in iron toxicity and its rapid cellular uptake, it may play an important role in the harmful effects of iron in infection, and this is illustrated by the infectious complications of parenteral iron therapy in tropical countries.
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Affiliation(s)
- Chaim Hershko
- Department of Hematology, Hebrew University Hadassah Medical School, Shaare Zedek Medical Center, Jerusalem, Israel.
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22
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Abstract
High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as "Trojan horse" toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.
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Affiliation(s)
- Marcus Miethke
- Philipps Universität Marburg, FB Chemie Biochemie, Hans Meerwein Strasse, D-35032 Marburg, Germany
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23
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Ma Y, Liu Z, Hider RC, Petrat F. Determination of the Labile Iron Pool of Human Lymphocytes using the Fluorescent Probe, CP655. ANALYTICAL CHEMISTRY INSIGHTS 2007. [DOI: 10.4137/117739010700200005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The present study introduces a method for determining the labile iron pool (LIP) in human lymphocytes. It is measured using the probe CP655, the fluorescence of which is stoichiometrically quenched by the addition of iron. The intracellular CP655 fluorescence in lymphocytes was quenched by increasing intracellular iron concentrations using the highly lipophilic 8-hydroxyquinoline iron complex. Intracellular fluorescence quenching, mediated by the physiological intracellular labile iron, can be recovered on the addition of excess membrane-permeable iron chelator, CP94. The intracellular probe concentration was measured using laser scanning microscopy. An ex situ calibration was performed in a “cytosolic” medium based on the determined intracellular CP655 concentration and probe fluorescence quenching in the presence of iron. The concentration of the LIP of healthy human lymphocytes was determined to be 0.57 ± 0.27 μM. The use of the fluorescent probe CP655 renders it possible to record the time course of iron uptake and iron chelation by CP94 in single intact lymphocytes.
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Affiliation(s)
- Yongmin Ma
- Department of Pharmacy, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, U.K
| | - Zudong Liu
- Department of Pharmacy, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, U.K
| | - Robert C Hider
- Department of Pharmacy, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, U.K
| | - Frank Petrat
- Institut für Physiologische Chemie, Universitätsklinikum, Hufelandstr. 55, D-45122 Essen, Germany
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24
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Stocks P, Bray P, Barton V, Al-Helal M, Jones M, Araujo N, Gibbons P, Ward S, Hughes R, Biagini G, Davies J, Amewu R, Mercer A, Ellis G, O'Neill P. Evidence for a Common Non-Heme Chelatable-Iron-Dependent Activation Mechanism for Semisynthetic and Synthetic Endoperoxide Antimalarial Drugs. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604697] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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25
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Stocks PA, Bray PG, Barton VE, Al-Helal M, Jones M, Araujo NC, Gibbons P, Ward SA, Hughes RH, Biagini GA, Davies J, Amewu R, Mercer AE, Ellis G, O'Neill PM. Evidence for a Common Non-Heme Chelatable-Iron-Dependent Activation Mechanism for Semisynthetic and Synthetic Endoperoxide Antimalarial Drugs. Angew Chem Int Ed Engl 2007; 46:6278-83. [PMID: 17640025 DOI: 10.1002/anie.200604697] [Citation(s) in RCA: 105] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Paul A Stocks
- Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, UK
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26
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Schümann K, Ettle T, Szegner B, Elsenhans B, Solomons NW. On risks and benefits of iron supplementation recommendations for iron intake revisited. J Trace Elem Med Biol 2007; 21:147-68. [PMID: 17697954 DOI: 10.1016/j.jtemb.2007.06.002] [Citation(s) in RCA: 109] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2007] [Revised: 06/04/2007] [Accepted: 06/11/2007] [Indexed: 12/24/2022]
Abstract
Iron is an essential trace element with a high prevalence of deficiency in infants and in women of reproductive age from developing countries. Iron deficiency is frequently associated with anaemia and, thus, with reduced working capacity and impaired intellectual development. Moreover, the risk for premature delivery, stillbirth and impaired host-defence is increased in iron deficiency. Iron-absorption and -distribution are homeostatically regulated to reduce the risk for deficiency and overload. These mechanisms interact, in part, with the mechanisms of oxidative stress and inflammation and with iron availability to pathogens. In the plasma, fractions of iron may not be bound to transferrin and are hypothesised to participate in atherogenesis. Repleted iron stores and preceding high iron intakes reduce intestinal iron absorption which, however, offers no reliable protection against oral iron overload. Recommendations for dietary iron intake at different life stages are given by the US Food and Nutrition Board (FNB), by FAO/WHO and by the EU Scientific Committee, among others. They are based, on estimates for iron-losses, iron-bioavailability from the diet, and iron-requirements for metabolism and growth. Differences in choice and interpretation of these estimates lead to different recommendations by the different panels which are discussed in detail. Assessment of iron-related risks is based on reports of adverse health effects which were used in the attempts to derive an upper safe level for dietary iron intake. Iron-related harm can be due to direct intestinal damage, to oxidative stress, or to stimulated growth of pathogens. Unfortunately, it is problematic to derive a reproducible cause-effect and dose-response relationship for adverse health effects that suggest a relationship to iron-intake, be they based on mechanistic or epidemiological observations. Corresponding data and interpretations are discussed for the intestinal lumen, the vascular system and for the intracellular and interstitial space, considering interference of the mechanisms of iron homoeostasis as a likely explanation for differences in epidemiological observations.
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Affiliation(s)
- Klaus Schümann
- Science Center Weihenstephan, Technical University Munich, Am Forum 5, D-85350, Freising, Germany.
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27
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Scholl PF, Tripathi AK, Sullivan DJ. Bioavailable iron and heme metabolism in Plasmodium falciparum. Curr Top Microbiol Immunol 2006; 295:293-324. [PMID: 16265896 DOI: 10.1007/3-540-29088-5_12] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Iron metabolism is essential for cell function and potentially toxic because iron can catalyze oxygen radical production. Malaria-attributable anemia and iron deficiency anemia coincide as being treatable diseases in the developing world. In absolute amounts, more than 95% of Plasmodium metal biochemistry occurs in the acidic digestive vacuole where heme released from hemoglobin catabolism forms heme crystals. The antimalarial quinolines interfere with crystallization. Despite the completion of the Plasmodium genome, many 'gene gaps' exist in components of the metal pathways described in mammalian or yeast cells. Present evidence suggests that parasite bioavailable iron originates from a labile erythrocyte cytosolic pool rather than from abundant heme iron. Indeed the parasite has to make its own heme within two separate organelles, the mitochondrion and the apicomplast. Paradoxically, despite the abundance of iron within the erythrocyte, iron chelators are cytocidal to the Plasmodium parasite. Hemozoin has become a sensitive biomarker for laser desorption mass spectrometry detection of Plasmodium infection in both mice and humans.
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Affiliation(s)
- P F Scholl
- Department of Environmental Health Sciences, Baltimore, MD 21205, USA
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28
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Gordeuk VR, Loyevsky M. Antimalarial effect of iron chelators. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 509:251-72. [PMID: 12572998 DOI: 10.1007/978-1-4615-0593-8_13] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Affiliation(s)
- Victor R Gordeuk
- George Washington University Medical Center, 2150 Pennsylvania Ave NW, Washington, DC 20037, USA
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29
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Darbari D, Loyevsky M, Gordeuk V, Kark JA, Castro O, Rana S, Apprey V, Kurantsin-Mills J. Fluorescence measurements of the labile iron pool of sickle erythrocytes. Blood 2003; 102:357-64. [PMID: 12623854 DOI: 10.1182/blood-2002-03-0914] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Sickle erythrocytes have increased ferritin and increased molecular iron on the inner membrane leaflet, and we postulated that cytosolic labile iron is also elevated. We used the fluorescent metallosensor, calcein, and a permeant Fe2+ chelator to estimate labile cytoslic Fe2+, and calcein plus an Fe3+ chelator to estimate total cytosolic labile iron (Fe2+ + Fe3+). We measured membrane nonheme iron by its reactivity with ferrozine. As estimated by calcein and Fe2+ chelator, the mean +/- SD labile Fe2+ concentration was significantly lower in hemoglobin (Hb) SS (n = 29) than hemoglobin AA (n = 17) erythrocytes (0.56 +/- 0.35 microM versus 1.25 +/- 0.65 microM; P <.001). In contrast, as estimated by calcein and Fe3+ chelator, total erythrocyte labile iron was similar in hemoglobin SS (n = 12) and hemoglobin AA (n = 10) participants (1.75 +/- 0.41 microM versus 2.14 +/- 0.93 microM; P =.2). Mean membrane nonheme iron levels were higher in hemoglobin SS cells than hemoglobin AA cells (0.0016 x 10-4 versus 0.0004 x 10-4 fmol/cell; P =.01), but much lower than the mean amounts of total labile iron (1.6-1.8 x 10-4 fmol/cell) or hemoglobin iron (18 000-19 000 x 10-4 fmol/cell). Both membrane iron and total labile iron were much less than the mean amount of iron potentially present in erythrocyte ferritin as calculated from results of other investigators (15 x 10-4 versus 34 x 10-4 fmol/cell in HbAA versus HbSS erythrocytes). We conclude that cytosolic labile iron is not elevated in hemoglobin SS erythrocytes and that elemental membrane iron is present in only trace amounts.
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Affiliation(s)
- Deepika Darbari
- Center for Sickle Cell Disease, Department of Biophysics and Physiology, University Hospital, Howard University College of Medicine, 2121 Georgia Avenue NW, Washington, DC 20060, USA
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30
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Abstract
Measurement of micronutrient status in the presence of inflammation is difficult for several reasons. Changes in levels of acute phase proteins are associated with increased plasma levels of some indicators of micronutrient status, such as ferritin, and decrease of others, such as retinol. Alterations in the plasma levels of acute phase proteins can occur from hemodilution, sequestration and increased or decreased rates of synthesis and breakdown. How much these relate to functional deficiency is not known. Assays that are less perturbed by inflammation, such as the transferrin receptor assay, and adjustment of plasma micronutrient levels according to different cutoff levels for acute phase proteins are helpful but they do not enable precise assessment of micronutrient status among individuals who are infected. Improving assessment of micronutrient status is important if micronutrient interventions are to be targeted to those with the greatest need.
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Affiliation(s)
- Andrew Tomkins
- Centre for International Health, Institute of Child Health, University College London, WC1N 1EH.
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31
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Espósito BP, Epsztejn S, Breuer W, Cabantchik ZI. A review of fluorescence methods for assessing labile iron in cells and biological fluids. Anal Biochem 2002; 304:1-18. [PMID: 11969183 DOI: 10.1006/abio.2002.5611] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A variety of biochemical, pharmacological, and toxicological properties have been attributed to labile forms of iron that are associated with cells or with biological fluids. Unlike the major fraction of bioiron which is protein bound, the labile bioiron is chelatable and therefore amenable for detection by metal-sensing devices that are coupled to chelation moieties. The present review deals with the detection of various labile forms of iron present in living cells and in fluids of biological interest, in health and disease. The main focus of the review is on the design and application of fluorescent probes as analytical tools for assessing labile iron and iron transport mechanisms and the efficiency of iron chelators in solution and in cellular systems.
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Affiliation(s)
- Breno P Espósito
- Department of Biological Chemistry, Hebrew University of Jerusalem, Jerusalem, 91904, Israel
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32
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Emerson LR, Nau ME, Martin RK, Kyle DE, Vahey M, Wirth DF. Relationship between chloroquine toxicity and iron acquisition in Saccharomyces cerevisiae. Antimicrob Agents Chemother 2002; 46:787-96. [PMID: 11850263 PMCID: PMC127479 DOI: 10.1128/aac.46.3.787-796.2002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Chloroquine is one of the most effective antimalarials, but resistance to it is becoming widespread. However, we do not fully understand either the drug's mode of action or the mechanism of resistance. In an effort to expand our understanding of the mechanism of action and resistance associated with chloroquine, we used Saccharomyces cerevisiae as a model eukaryotic system. To aid in the discovery of potential drug targets we applied the transcriptional profiling method to identify genes transcriptionally responsive to chloroquine treatment in S. cerevisiae. Among the genes that were differentially expressed with chloroquine treatment were a number of metal transporters involved in iron acquisition (SIT1, ARN2, ARN4, and SMF2). These genes exhibit similar expression patterns, and several are known to be regulated by AFT1, a DNA binding protein, which responds to iron levels in the cell. We investigated the role of chloroquine in iron metabolism by using a variety of approaches, including pharmacological, genetic, and biochemical techniques. For these experiments, we utilized yeast lacking the major iron uptake pathways (FET3 and FET4) and yeast deficient in SIT1, encoding the major up-regulated iron siderophore transporter. Our experiments show that yeast genetically or environmentally limited in iron availability has increased sensitivity to chloroquine in pharmacological assays and that the addition of iron rescues these cells from chloroquine killing. 55FeCl3 accumulation was inhibited in the presence of chloroquine, and kinetic analysis demonstrated that inhibition was competitive. These results are consistent with deprivation of iron as a mechanism of chloroquine killing in yeast.
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Affiliation(s)
- Lyndal R Emerson
- Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, Massachusetts 02115, USA
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33
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Petrat F, de Groot H, Sustmann R, Rauen U. The chelatable iron pool in living cells: a methodically defined quantity. Biol Chem 2002; 383:489-502. [PMID: 12033438 DOI: 10.1515/bc.2002.051] [Citation(s) in RCA: 153] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
A very small, predominantly cytosolic pool of iron ions plays the central role in the cellular iron metabolism. It links the cellular iron uptake with the insertion of the metal in iron storage proteins and other essential iron-containing molecules. Furthermore, this transit ('labile') pool is essentially involved in the pathogenesis of a number of diseases. Due to its high physiological and pathophysiological significance, numerous methods for its characterization have been developed during the last five decades. Most of these methods, however, influence the size and nature of the transit iron pool artificially, as they are not applicable to viable biological material. Recently, fluorescence spectroscopic methods for measurements within viable cells have become available. Although these methods avoid the artifacts of previous methods, studies using fluorescent iron indicators revealed that the 'intracellular transit iron pool', which is methodically assessed as 'chelatable iron', is substantially defined by the method and/or the iron-chelating indicator applied for its detection, since the iron ions are bound to a large number of different ligands in different metabolic compartments. A more comprehensive characterization of the nature and the role of the thus not uniform cellular transit iron pool therefore requires parallel employment of different indicator molecules, which clearly differ in their intracellular distribution and their physico-chemical characteristics.
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Affiliation(s)
- Frank Petrat
- Institut für Physiologische Chemie, Universitätsklinikum Essen, Germany
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34
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Loyevsky M, LaVaute T, Allerson CR, Stearman R, Kassim OO, Cooperman S, Gordeuk VR, Rouault TA. An IRP-like protein from Plasmodium falciparum binds to a mammalian iron-responsive element. Blood 2001; 98:2555-62. [PMID: 11588054 DOI: 10.1182/blood.v98.8.2555] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
This study cloned and sequenced the complementary DNA (cDNA) encoding of a putative malarial iron responsive element-binding protein (PfIRPa) and confirmed its identity to the previously identified iron-regulatory protein (IRP)-like cDNA from Plasmodium falciparum. Sequence alignment showed that the plasmodial sequence has 47% identity with human IRP1. Hemoglobin-free lysates obtained from erythrocyte-stage P falciparum contain a protein that binds a consensus mammalian iron-responsive element (IRE), indicating that a protein(s) with iron-regulatory activity was present in the lysates. IRE-binding activity was found to be iron regulated in the electrophoretic mobility shift assays. Western blot analysis showed a 2-fold increase in the level of PfIRPa in the desferrioxamine-treated cultures versus control or iron-supplemented cells. Malarial IRP was detected by anti-PfIRPa antibody in the IRE-protein complex from P falciparum lysates. Immunofluorescence studies confirmed the presence of PfIRPa in the infected red blood cells. These findings demonstrate that erythrocyte P falciparum contains an iron-regulated IRP that binds a mammalian consensus IRE sequence, raising the possibility that the malaria parasite expresses transcripts that contain IREs and are iron-dependently regulated.
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Oppenheimer SJ. Iron and its relation to immunity and infectious disease. J Nutr 2001; 131:616S-633S; discussion 633S-635S. [PMID: 11160594 DOI: 10.1093/jn/131.2.616s] [Citation(s) in RCA: 392] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The continuing unresolved debate over the interaction of iron and infection indicates a need for quantitative review of clinical morbidity outcomes. Iron deficiency is associated with reversible abnormalities of immune function, but it is difficult to demonstrate the severity and relevance of these in observational studies. Iron treatment has been associated with acute exacerbations of infection, in particular, malaria. Oral iron has been associated with increased rates of clinical malaria (5 of 9 studies) and increased morbidity from other infectious disease (4 of 8 studies). In most instances, therapeutic doses of oral iron were used. No studies in malarial regions showed benefits. Knowledge of local prevalence of causes of anemia including iron deficiency, seasonal malarial endemicity, protective hemoglobinopathies and age-specific immunity is essential in planning interventions. A balance must be struck in dose of oral iron and the timing of intervention with respect to age and malaria transmission. Antimalarial intervention is important. No studies of oral iron supplementation clearly show deleterious effects in nonmalarious areas. Milk fortification reduced morbidity due to respiratory disease in two very early studies in nonmalarious regions, but this was not confirmed in three later fortification studies, and better morbidity rates could be achieved by breast-feeding alone. One study in a nonmalarious area of Indonesia showed reduced infectious outcome after oral iron supplementation of anemic schoolchildren. No systematic studies report oral iron supplementation and infectious morbidity in breast-fed infants in nonmalarious regions.
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Schwart W, Judd D, Wysocki M, Guerrier L, Birck-Wilson E, Boschetti E. Comparison of hydrophobic charge induction chromatography with affinity chromatography on protein A for harvest and purification of antibodies. J Chromatogr A 2001; 908:251-63. [PMID: 11218128 DOI: 10.1016/s0021-9673(00)01013-x] [Citation(s) in RCA: 117] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Efficient harvest and recovery of high-purity monoclonal antibodies was achieved using hydrophobic charge induction chromatography (HCIC). Both simple and complex feedstocks were studied, including protein-free cell culture supernatant and the clarified/concentrated milk of transgenic goats. Viral clearance studies demonstrated a 4-log reduction of MVM virus (minute virus of mice), along with substantial reduction of DNA content. Sorbent characterization studies confirmed that HCIC is based on the pH-dependent behavior of a dual-mode, ionizable ligand. Binding, based on hydrophobic interaction, was achieved under near-physiological conditions, and in the absence of lyotropic salt. Desorption was accomplished under mild conditions--pH 4.0. At this pH, both ligand and antibody carry a net positive charge, and desorption occurs on the basis of electrostatic charge repulsion. pH-based control of chromatographic function was demonstrated. Chromatography on this antibody-selective HCIC sorbent was evaluated as a cost-effective, process-compatible alternative to affinity chromatography protein A sorbents.
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Affiliation(s)
- W Schwart
- BioSepra Process Chromatography, Life Technologies, A Division of Invitrogen Corporation, Rockville, MD 20850, USA.
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