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Gracheva M, Klencsár Z, Homonnay Z, Solti Á, Péter L, Machala L, Novak P, Kovács K. Revealing the nuclearity of iron citrate complexes at biologically relevant conditions. Biometals 2024; 37:461-475. [PMID: 38110781 PMCID: PMC11006783 DOI: 10.1007/s10534-023-00562-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 11/09/2023] [Indexed: 12/20/2023]
Abstract
Citric acid plays an ubiquitous role in the complexation of essential metals like iron and thus it has a key function making them biologically available. For this, iron(III) citrate complexes are considered among the most significant coordinated forms of ferric iron that take place in biochemical processes of all living organisms. Although these systems hold great biological relevance, their coordination chemistry has not been fully elucidated yet. The current study aimed to investigate the speciation of iron(III) citrate using Mössbauer and electron paramagnetic resonance spectroscopies. Our aim was to gain insights into the structure and nuclearity of the complexes depending on the pH and iron to citrate ratio. By applying the frozen solution technique, the results obtained directly reflect the iron speciation present in the aqueous solution. At 1:1 iron:citrate molar ratio, polynuclear species prevailed forming most probably a trinuclear structure. In the case of citrate excess, the coexistence of several monoiron species with different coordination environments was confirmed. The stability of the polynuclear complexes was checked in the presence of organic solvents.
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Affiliation(s)
- Maria Gracheva
- Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány P. s. 1/A, 1117, Budapest, Hungary
- Nuclear Analysis and Radiography Department, Centre for Energy Research, Konkoly-Thege Miklós út. 29-33, 1121, Budapest, Hungary
| | - Zoltán Klencsár
- Nuclear Analysis and Radiography Department, Centre for Energy Research, Konkoly-Thege Miklós út. 29-33, 1121, Budapest, Hungary
| | - Zoltán Homonnay
- Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány P. s. 1/A, 1117, Budapest, Hungary
| | - Ádám Solti
- Department of Plant Physiology and Molecular Plant Biology, Institute of Biology, ELTE Eötvös Loránd University, Pázmány Péter s. 1/C, 1117, Budapest, Hungary
| | - László Péter
- Department of Complex Fluids, Institute for Solid State Physics and Optics, Wigner Research Centre for Physics, Konkoly-Thege Miklós út 29-33, 1121, Budapest, Hungary
| | - Libor Machala
- Department of Experimental Physics, Faculty of Science, Palacký University Olomouc, 17. listopadu 1192/12, 771 46, Olomouc, Czech Republic
| | - Petr Novak
- Department of Experimental Physics, Faculty of Science, Palacký University Olomouc, 17. listopadu 1192/12, 771 46, Olomouc, Czech Republic
| | - Krisztina Kovács
- Department of Analytical Chemistry, Institute of Chemistry, ELTE Eötvös Loránd University, Pázmány P. s. 1/A, 1117, Budapest, Hungary.
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2
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Zhao Z. Hydroxyl radical generations form the physiologically relevant Fenton-like reactions. Free Radic Biol Med 2023; 208:510-515. [PMID: 37717792 DOI: 10.1016/j.freeradbiomed.2023.09.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/23/2023] [Accepted: 09/14/2023] [Indexed: 09/19/2023]
Abstract
Iron(II) species can participate in the Fenton and Fenton-like reactions to generate the hydroxyl radical that can oxidatively damage biomolecules and induce oxidative stress in biological systems. Many diseases, including neurodegeneration, cardiovascular disease and cancer, are associated with oxidative stress. However, it is proposed recently that hydroxyl radical would not be generated from the Fenton reaction under physiological conditions and thus would not cause oxidative stress in biological systems. This proposal may cause confusion for understanding oxidative stress and can also have impact on therapeutic strategies for the diseases associated with oxidative stress. In this Mini-review, the up-to-date convincing evidences of hydroxyl radical generation from the physiologically relevant Fenton-like reactions of the iron(II) complexes with physiological ligands in human blood plasma, including histidine, citrate and phosphate, are succinctly reviewed. The oxidative damages caused by hydroxyl radical to biomolecules and cells are briefly summarized. These findings strongly challenge the above proposal.
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Affiliation(s)
- Zhongwei Zhao
- School of Pharmaceutical Sciences, Capital Medical University, Beijing, 100069, China; College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, China.
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3
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Indurkar A, Choudhary R, Rubenis K, Nimbalkar M, Sarakovskis A, Boccaccini AR, Locs J. Amorphous Calcium Phosphate and Amorphous Calcium Phosphate Carboxylate: Synthesis and Characterization. ACS OMEGA 2023; 8:26782-26792. [PMID: 37546623 PMCID: PMC10399191 DOI: 10.1021/acsomega.3c00796] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 06/27/2023] [Indexed: 08/08/2023]
Abstract
Amorphous calcium phosphate (ACP) is the first solid phase precipitated from a supersaturated calcium phosphate solution. Naturally, ACP is formed during the initial stages of biomineralization and stabilized by an organic compound. Carboxylic groups containing organic compounds are known to regulate the nucleation and crystallization of hydroxyapatite. Therefore, from a biomimetic point of view, the synthesis of carboxylate ions containing ACP (ACPC) is valuable. Usually, ACP is synthesized with fewer steps than ACPC. The precipitation reaction of ACP is rapid and influenced by pH, temperature, precursor concentration, stirring conditions, and reaction time. Due to phosphates triprotic nature, controlling pH in a multistep approach becomes tedious. Here, we developed a new ACP and ACPC synthesis approach and thoroughly characterized the obtained materials. Results from vibration spectroscopy, nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), true density, specific surface area, and ion release studies have shown a difference in the physiochemical properties of the ACP and ACPC. Additionally, the effect of a carboxylic ion type on the physiochemical properties of ACPC was characterized. All of the ACPs and ACPCs were synthesized in sterile conditions, and in vitro analysis was performed using MC-3T3E1 cells, revealing the cytocompatibility of the synthesized ACPs and ACPCs, of which the ACPC synthesized with citrate showed the highest cell viability.
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Affiliation(s)
- Abhishek Indurkar
- Rudolfs
Cimdins Riga Biomaterials Innovations and Development Centre of RTU,
Institute of General Chemical Engineering, Faculty of Materials Science
and Applied Chemistry, Riga Technical University, Pulka Street 3, LV-1007 Riga, Latvia
- Baltic
Biomaterials Centre of Excellence, Headquarters
at Riga Technical University, Kipsalas Street 6A, LV-1048 Riga, Latvia
| | - Rajan Choudhary
- Rudolfs
Cimdins Riga Biomaterials Innovations and Development Centre of RTU,
Institute of General Chemical Engineering, Faculty of Materials Science
and Applied Chemistry, Riga Technical University, Pulka Street 3, LV-1007 Riga, Latvia
- Baltic
Biomaterials Centre of Excellence, Headquarters
at Riga Technical University, Kipsalas Street 6A, LV-1048 Riga, Latvia
| | - Kristaps Rubenis
- Rudolfs
Cimdins Riga Biomaterials Innovations and Development Centre of RTU,
Institute of General Chemical Engineering, Faculty of Materials Science
and Applied Chemistry, Riga Technical University, Pulka Street 3, LV-1007 Riga, Latvia
- Baltic
Biomaterials Centre of Excellence, Headquarters
at Riga Technical University, Kipsalas Street 6A, LV-1048 Riga, Latvia
| | | | - Anatolijs Sarakovskis
- Institute
of Solid State Physics, University of Latvia, 8 Kengaraga Str., LV-1063 Riga, Latvia
| | - Aldo R. Boccaccini
- Institute
of Biomaterials, Department of Material Science and Engineering, University of Erlangen-Nuremberg, 91085 Erlangen, Germany
| | - Janis Locs
- Rudolfs
Cimdins Riga Biomaterials Innovations and Development Centre of RTU,
Institute of General Chemical Engineering, Faculty of Materials Science
and Applied Chemistry, Riga Technical University, Pulka Street 3, LV-1007 Riga, Latvia
- Baltic
Biomaterials Centre of Excellence, Headquarters
at Riga Technical University, Kipsalas Street 6A, LV-1048 Riga, Latvia
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4
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Vali SW, Lindahl PA. Low-temperature Mössbauer spectroscopy of organs from 57Fe-enriched HFE (-/-) hemochromatosis mice: an iron-dependent threshold for generating hemosiderin. J Biol Inorg Chem 2023; 28:173-185. [PMID: 36512071 PMCID: PMC9981716 DOI: 10.1007/s00775-022-01975-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/26/2022] [Indexed: 12/15/2022]
Abstract
Hereditary hemochromatosis is an iron-overload disease most often arising from a mutation in the Homeostatic Fe regulator (HFE) gene. HFE organs become overloaded with iron which causes damage. Iron-overload is commonly detected by NMR imaging, but the spectroscopic technique is insensitive to diamagnetic iron. Here, we used Mössbauer spectroscopy to examine the iron content of liver, spleen, kidney, heart, and brain of 57Fe-enriched HFE(-/-) mice of ages 3-52 wk. Overall, the iron contents of all investigated HFE organs were similar to the same healthy organ but from an older mouse. Livers and spleens were majorly overloaded, followed by kidneys. Excess iron was generally present as ferritin. Iron-sulfur clusters and low-spin FeII hemes (combined into the central quadrupole doublet) and nonheme high-spin FeII species were also observed. Spectra of young and middle-aged HFE kidneys were dominated by the central quadrupole doublet and were largely devoid of ferritin. Collecting and comparing spectra at 5 and 60 K allowed the presence of hemosiderin, a decomposition product of ferritin, to be quantified, and it also allowed the diamagnetic central doublet to be distinguished from ferritin. Hemosiderin was observed in spleens and livers from HFE mice, and in spleens from controls, but only when iron concentrations exceeded 2-3 mM. Even in those cases, hemosiderin represented only 10-20% of the iron in the sample. NMR imaging can identify iron-overload under non-invasive room-temperature conditions, but Mössbauer spectroscopy of 57Fe-enriched mice can detect all forms of iron and perhaps allow the process of iron-overloading to be probed in greater detail.
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Affiliation(s)
- Shaik Waseem Vali
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA
| | - Paul A Lindahl
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, USA.
- Department of Chemistry, Texas A&M University, College Station, TX, 77843-3255, USA.
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5
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Garbowski MW, Cabantchik I, Hershko C, Hider R, Porter JB. The clinical relevance of detectable plasma iron species in iron overload states and subsequent to intravenous iron-carbohydrate administration. Am J Hematol 2023; 98:533-540. [PMID: 36565452 DOI: 10.1002/ajh.26819] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 10/20/2022] [Accepted: 11/26/2022] [Indexed: 12/25/2022]
Abstract
Many disorders of iron homeostasis (e.g., iron overload) are associated with the dynamic kinetic profiles of multiple non-transferrin bound iron (NTBI) species, chronic exposure to which is associated with deleterious end-organ effects. Here we discuss the chemical nature of NTBI species, challenges with measuring NTBI in plasma, and the clinical relevance of NTBI exposure based on source (iron overload disorder vs. intravenous iron-carbohydrate complex administration). NTBI is not a single entity but consists of multiple, often poorly characterized species, some of which are kinetically non-exchangeable while others are relatively exchangeable. Prolonged presence of plasma NTBI is associated with excessive tissue iron accumulation in susceptible tissues, with consequences, such as endocrinopathy and heart failure. In contrast, intravenous iron-carbohydrate nanomedicines administration leads only to transient NTBI appearance and lacks evidence for association with adverse clinical outcomes. Assays to measure plasma NTBI are typically technically complex and remain chiefly a research tool. There have been two general approaches to estimating NTBI: capture assays and redox-activity assays. Early assays could not avoid capturing some iron from transferrin, thus overestimating NTBI. By contrast, some later assays may have promoted the donation of NTBI species to transferrin during the assay procedure, potentially underestimating NTBI levels. The levels of transferrin saturation at which NTBI species have been detectable have varied between different methodologies and between patient populations studied.
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Affiliation(s)
- Maciej W Garbowski
- Cancer Institute Haematology Department, University College London, London, United Kingdom.,London Metallomics Consortium, London, United Kingdom
| | - Ioav Cabantchik
- Alexander Silberman Institute of Life Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Chaim Hershko
- Shaare Zedek Medical Center, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Robert Hider
- London Metallomics Consortium, London, United Kingdom.,Institute of Pharmaceutical Science, King's College London, London, United Kingdom
| | - John B Porter
- Cancer Institute Haematology Department, University College London, London, United Kingdom
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6
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Vali SW, Lindahl PA. Might nontransferrin-bound iron in blood plasma and sera be a nonproteinaceous high-molecular-mass Fe III aggregate? J Biol Chem 2022; 298:102667. [PMID: 36334631 PMCID: PMC9768373 DOI: 10.1016/j.jbc.2022.102667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Revised: 10/26/2022] [Accepted: 10/30/2022] [Indexed: 11/11/2022] Open
Abstract
The HFE (Homeostatic Fe regulator) gene is commonly mutated in hereditary hemochromatosis. Blood of (HFE)(-/-) mice and of humans with hemochromatosis contains toxic nontransferrin-bound iron (NTBI) which accumulates in organs. However, the chemical composition of NTBI is uncertain. To investigate, HFE(-/-) mice were fed iron-deficient diets supplemented with increasing amounts of iron, with the expectation that NTBI levels would increase. Blood plasma was filtered to obtain retentate and flow-through solution fractions. Liquid chromatography detected by inductively coupled plasma mass spectrometry of flow-through solutions exhibited low-molecular-mass iron peaks that did not increase intensity with increasing dietary iron. Retentates yielded peaks due to transferrin (TFN) and ferritin, but much iron in these samples adsorbed onto the column. Retentates treated with the chelator deferoxamine (DFO) yielded a peak that comigrated with the Fe-DFO complex and originated from iron that adhered to the column in the absence of DFO. Additionally, plasma from younger and older 57Fe-enriched HFE mice were separately pooled and concentrated by ultrafiltration. After removing contributions from contaminating blood and TFN, Mössbauer spectra were dominated by features due to magnetically interacting FeIII aggregates, with greater intensity in the spectrum from the older mice. Similar features were generated by adding 57FeIII to "pseudo plasma". Aggregation was unaffected by albumin or citrate at physiological concentrations, but DFO or high citrate concentrations converted aggregated FeIII into high-spin FeIII complexes. FeIII aggregates were retained by the cutoff membrane and adhered to the column, similar to the behavior of NTBI. A model is proposed in which FeII entering blood is oxidized, and if apo-TFN is unavailable, the resulting FeIII ions coalesce into FeIII aggregates, a.k.a. NTBI.
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Affiliation(s)
- Shaik Waseem Vali
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Paul A Lindahl
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA; Department of Chemistry, Texas A&M University, College Station, Texas, USA.
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7
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Angoro B, Motshakeri M, Hemmaway C, Svirskis D, Sharma M. Non-transferrin bound iron. Clin Chim Acta 2022; 531:157-167. [DOI: 10.1016/j.cca.2022.04.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 12/31/2022]
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8
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The (Bio)Chemistry of Non-Transferrin-Bound Iron. Molecules 2022; 27:molecules27061784. [PMID: 35335148 PMCID: PMC8951307 DOI: 10.3390/molecules27061784] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 12/14/2022] Open
Abstract
In healthy individuals, virtually all blood plasma iron is bound by transferrin. However, in several diseases and clinical conditions, hazardous non-transferrin-bound iron (NTBI) species occur. NTBI represents a potentially toxic iron form, being a direct cause of oxidative stress in the circulating compartment and tissue iron loading. The accumulation of these species can cause cellular damage in several organs, namely, the liver, spleen, and heart. Despite its pathophysiological relevance, the chemical nature of NTBI remains elusive. This has precluded its use as a clinical biochemical marker and the development of targeted therapies. Herein, we make a critical assessment of the current knowledge of NTBI speciation. The currently accepted hypotheses suggest that NTBI is mostly iron bound to citric acid and iron bound to serum albumin, but the chemistry of this system remains fuzzy. We explore the complex chemistry of iron complexation by citric acid and its implications towards NTBI reactivity. Further, the ability of albumin to bind iron is revised and the role of protein post-translational modifications on iron binding is discussed. The characterization of the NTBI species structure may be the starting point for the development of a standardized analytical assay, the better understanding of these species’ reactivity or the identification of NTBI uptake mechanisms by different cell types, and finally, to the development of new therapies.
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9
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Garbowski MW, Porter JB, Hider R. Response to Cabantchik and Hershko commentary "Plasma nontransferrin bound iron-nontransferrin bound iron revisited: Implications for systemic iron overload and in iv iron supplementation". Am J Hematol 2022; 97:E58-E59. [PMID: 34817863 DOI: 10.1002/ajh.26419] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Accepted: 11/16/2021] [Indexed: 11/12/2022]
Affiliation(s)
- Maciej W. Garbowski
- Haematology Department, Cancer Institute University College London London UK
| | - John B. Porter
- Haematology Department, Cancer Institute University College London London UK
| | - Robert Hider
- Institute for Pharmaceutical Science King's College London London UK
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10
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Cabantchik IZ, Hershko C. Plasma nontransferrin bound iron-nontransferrin bound iron revisited: Implications for systemic iron overload and in iv iron supplementation. Am J Hematol 2022; 97:7-9. [PMID: 34637551 DOI: 10.1002/ajh.26374] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/24/2022]
Affiliation(s)
- Ioav Z Cabantchik
- Institute of Life Sciences, Faculty of Natural Sciences, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Chaim Hershko
- Institute of Medicine, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
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11
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Leal LB, Nogueira MS, Mageski JGA, Martini TP, Barauna VG, Dos Santos L, de Carvalho LFDCES. Diagnosis of Systemic Diseases Using Infrared Spectroscopy: Detection of Iron Overload in Plasma-Preliminary Study. Biol Trace Elem Res 2021; 199:3737-3751. [PMID: 33415581 DOI: 10.1007/s12011-020-02510-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 11/23/2020] [Indexed: 02/07/2023]
Abstract
Despite the important role of iron in cellular homeostasis, iron overload (IO) is associated with systemic and tissue deposits which damage several organs. In order to reduce the impact caused by IO, invasive diagnosis exams (e.g., biopsies) and minimally invasive methods were developed including computed tomography and magnetic resonance imaging. However, current diagnostic methods are still time-consuming and expensive. A cost-effective solution is using Fourier-transform infrared spectroscopy (FTIR) for real-time and molecular-sensitive biofluid analysis during conventional laboratory exams. In this study, we performed the first evaluation of the accuracy of FTIR for IO diagnosis. The study was performed by collecting FTIR spectra of plasma samples of five rats intravenously injected with iron-dextran and five control rats. We developed a classification model based on principal component analysis and supervised methods including J48, random forest, multilayer perceptron, and radial basis function network. We achieved 100% accuracy for the classification of the IO status and provided a list of possible biomolecules related to the vibrational modes detected. In this preliminary study, we give a first step towards real-time diagnosis for acute IO or intoxication. Furthermore, we have expanded the literature knowledge regarding the pathophysiological changes induced by iron overload.
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Affiliation(s)
- Leonardo Barbosa Leal
- Department of Physiological Sciences, Federal University of Espírito Santo (UFES), Marechal Campos Ave, 1468, Maruípe, Vitória, Espírito Santo, 29040-090, Brazil.
| | - Marcelo Saito Nogueira
- Tyndall National Institute/University College Cork - Lee Maltings Complex, Dyke Parade, Cork, T12R5CP, Ireland
| | - Jandinay Gonzaga Alexandre Mageski
- Department of Physiological Sciences, Federal University of Espírito Santo (UFES), Marechal Campos Ave, 1468, Maruípe, Vitória, Espírito Santo, 29040-090, Brazil
| | - Thiago Pereira Martini
- Institute of Science and Technology, Federal University of Sao Paulo, São José dos Campos, Brazil
| | - Valério Garrone Barauna
- Department of Physiological Sciences, Federal University of Espírito Santo (UFES), Marechal Campos Ave, 1468, Maruípe, Vitória, Espírito Santo, 29040-090, Brazil
| | - Leonardo Dos Santos
- Department of Physiological Sciences, Federal University of Espírito Santo (UFES), Marechal Campos Ave, 1468, Maruípe, Vitória, Espírito Santo, 29040-090, Brazil
| | - Luis Felipe das Chagas E Silva de Carvalho
- Universidade de Taubaté. R. dos Operários, 09 - Centro, Taubaté, São Paulo, 12020-340, Brazil
- Centro Universitário Braz Cubas, Av. Francisco Rodrigues Filho, 1233 - Vila Mogilar, Mogi das Cruzes, São Paulo, Brazil
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12
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Soma S, Morgada MN, Naik MT, Boulet A, Roesler AA, Dziuba N, Ghosh A, Yu Q, Lindahl PA, Ames JB, Leary SC, Vila AJ, Gohil VM. COA6 Is Structurally Tuned to Function as a Thiol-Disulfide Oxidoreductase in Copper Delivery to Mitochondrial Cytochrome c Oxidase. Cell Rep 2020; 29:4114-4126.e5. [PMID: 31851937 PMCID: PMC6946597 DOI: 10.1016/j.celrep.2019.11.054] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/07/2019] [Accepted: 11/13/2019] [Indexed: 12/31/2022] Open
Abstract
In eukaryotes, cellular respiration is driven by mitochondrial cytochrome c oxidase (CcO), an enzyme complex that requires copper cofactors for its catalytic activity. Insertion of copper into its catalytically active subunits, including COX2, is a complex process that requires metallochaperones and redox proteins including SCO1, SCO2, and COA6, a recently discovered protein whose molecular function is unknown. To uncover the molecular mechanism by which COA6 and SCO proteins mediate copper delivery to COX2, we have solved the solution structure of COA6, which reveals a coiled-coil-helix-coiled-coil-helix domain typical of redox-active proteins found in the mitochondrial inter-membrane space. Accordingly, we demonstrate that COA6 can reduce the copper-coordinating disulfides of its client proteins, SCO1 and COX2, allowing for copper binding. Finally, our determination of the interaction surfaces and reduction potentials of COA6 and its client proteins provides a mechanism of how metallochaperone and disulfide reductase activities are coordinated to deliver copper to CcO. Soma et al. reports the solution structure of cytochrome c oxidase assembly factor COA6 and establishes that it functions as a thiol-disulfide oxidoreductase in a relay system that delivers copper to COX2, a copper-containing subunit of the mitochondrial cytochrome c oxidase.
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Affiliation(s)
- Shivatheja Soma
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Marcos N Morgada
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Área Biofísica, Departamento de Química Biológica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario (2000), Argentina
| | - Mandar T Naik
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Aren Boulet
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Anna A Roesler
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Nathaniel Dziuba
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Alok Ghosh
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA
| | - Qinhong Yu
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Paul A Lindahl
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA; Department of Chemistry, Texas A&M University, College Station, TX 77843, USA
| | - James B Ames
- Department of Chemistry, University of California, Davis, Davis, CA 95616, USA
| | - Scot C Leary
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada
| | - Alejandro J Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Área Biofísica, Departamento de Química Biológica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Rosario (2000), Argentina
| | - Vishal M Gohil
- Department of Biochemistry and Biophysics, MS 3474, Texas A&M University, College Station, TX 77843, USA.
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13
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Nguyen TQ, Dziuba N, Lindahl PA. Isolated Saccharomyces cerevisiae vacuoles contain low-molecular-mass transition-metal polyphosphate complexes. Metallomics 2020; 11:1298-1309. [PMID: 31210222 DOI: 10.1039/c9mt00104b] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Vacuoles play major roles in the trafficking, storage, and homeostasis of metal ions in fungi and plants. In this study, 29 batches of vacuoles were isolated from Saccharomyces cerevisiae. Flow-through solutions (FTS) obtained by passing vacuolar extracts through a 10 kDa cut-off membrane were characterized for metal content using an anaerobic liquid chromatography system interfaced to an online ICP-MS. Nearly all iron, zinc, and manganese ions in these solutions were present as low-molecular-mass (LMM) complexes. Metal-detected peaks with masses between 500-1700 Da dominated; phosphorus-detected peaks generally comigrated. The distribution of metal:polyphosphate complexes was dominated by particular chain-lengths rather than a broad binomial distribution. Similarly treated synthetic FeIII polyphosphate complexes showed similar peaks. Treatment with a phosphatase disrupted the LMM metal-bound species in vacuolar FTSs. These results indicated metal:polyphosphate complexes 6-20 phosphate units in length and coordinated by 1-3 metals on average per chain. The speciation of iron in FTSs from iron-deficient cells was qualitatively similar, but intensities were lower. Under healthy conditions, nearly all copper ions in vacuolar FTSs were present as 1-2 species with masses between 4800-7800 Da. The absence of these high-mass peaks in vacuolar FTS from cup1Δ cells suggests that they were due to metallothionein, Cup1. Disrupting copper homeostasis increased the amount of LMM copper:polyphosphate complexes in vacuoles (masses between 1500-1700 Da). Potentially dangerous LMM copper species in the cytosol of metallothionein-deficient cells may traffic into vacuoles for sequestration and detoxification.
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Affiliation(s)
- Trang Q Nguyen
- Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA.
| | - Nathaniel Dziuba
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Paul A Lindahl
- Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA. and Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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14
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Nguyen TQ, Kim JE, Brawley HN, Lindahl PA. Chromatographic detection of low-molecular-mass metal complexes in the cytosol of Saccharomyces cerevisiae. Metallomics 2020; 12:1094-1105. [PMID: 32301942 PMCID: PMC7497409 DOI: 10.1039/c9mt00312f] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Fluorescence-based chelators are commonly used to probe labile low-molecular-mass (LMM) metal pools in the cytosol of eukaryotic cells, but such chelators destroy the complexes of interest during detection. The objective of this study was to use chromatography to directly detect such complexes. Towards this end, 47 batches of cytosol were isolated from fermenting S. cerevisiae yeast cells and passed through a 10 kDa cut-off membrane. The metal contents of the cytosol and resulting flow-through solution (FTS) were determined. FTSs were applied to a size-exclusion LC column located in an anaerobic refrigerated glove box. The LC system was coupled to an online inductively-coupled-plasma mass spectrometer (ICP-MS) for detection of individual metals. Iron-detected chromatograms of cytosolic FTSs from WT cells exhibited 2-4 major species with apparent masses between 500-1300 Da. Increasing the iron concentration in the growth medium 40-fold increased the overall intensity of these peaks. Approximately 3 LMM cytosolic copper complexes with apparent masses between 300-1300 Da were also detected; their LC intensities were weak, but these increased with increasing concentrations of copper in the growth medium. Observed higher-mass copper-detected peaks were tentatively assigned to copper-bound metallothioneins Cup1 and Crs5. FTSs from strains in which Cup1 or the Cox17 copper chaperone were deleted altered the distribution of LMM copper complexes. LMM zinc- and manganese-detected species were also present in cytosol, albeit at low concentrations. Supplementing the growth medium with zinc increased the intensity of the zinc peak assigned to Crs5 but the intensities of LMM zinc complexes were unaffected. Phosphorus-detected chromatograms were dominated by peaks at apparent masses 400-800 Da, with minor peaks at 1000-1500 Da in some batches. Sulfur chromatograms contained a low-intensity peak that comigrated with a glutathione standard; quantification suggested a GSH concentration in the cytosol of ca. 13 mM. A second LMM sulfur peak that migrated at an apparent mass of 100 Da was also evident.
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Affiliation(s)
- Trang Q Nguyen
- Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA.
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15
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Lago L, Thomas ORB, Roberts BR. Choice of mobile phase: Implications for size exclusion chromatography-inductively coupled plasma-mass spectrometry analyses of copper, zinc and iron metalloproteins. J Chromatogr A 2020; 1616:460806. [PMID: 31916987 DOI: 10.1016/j.chroma.2019.460806] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 11/25/2022]
Abstract
The correct identification of the metalloproteins present in human tissues and fluids is essential to our understanding of the cellular mechanisms underpinning a host of health disorders. Separation and analysis of biological samples are typically done via size exclusion chromatography hyphenated with inductively coupled plasma-mass spectrometry (SEC-ICP-MS). Although this technique can be extremely effective in identification of potential metalloproteins, the choice of mobile phase may have a marked effect on results, results by adversely affecting metal-protein bonds of the metalloproteins of interest. To assess the choice of mobile phase on SEC-ICP-MS resolution and the resulting metalloproteome pattern, we analysed several different sample types (brain homogenate; Cu/Zn-superoxide dismutase (SOD1); a molecular weight standard mix containing ferritin (Ft), ceruloplasmin (Cp), cytochrome c (CytC), vitamin B12 (B12) and thyroglobulin (Tg) using six different mobile phase conditions (200 mM, pH 7.5 solutions of ammonium salts nitrate, acetate, and sulfate; HEPES, MOPS and Tris-HCl). Our findings suggest that ammonium nitrate, ammonium acetate and Tris-HCl are optimal choices for the mobile phase, with the specific choice being dependent on both the number of samples and method of detection that is hyphenated with separation. Furthermore, we found that MOPS, HEPES and ammonium sulfate mobile phases all caused significant changes to peak resolution, retention time and overall profile shape. MOPS and HEPES, in particular, produced additional Fe peaks that were not detected with any of the other mobile phases that were investigated. As well as this, MOPS and HEPES both caused significant concentration dependent matrix suppression of the internal standard.
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Affiliation(s)
- Larissa Lago
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Victoria, 3052, Australia
| | - Oliver R B Thomas
- School of BioSciences, The University of Melbourne, BioSciences 4, Royal Parade, Parkville, Victoria, 3052, Australia
| | - Blaine R Roberts
- Department of Biochemistry, Emory University School of Medicine, Atlanta, GA, 30322 USA.
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16
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Jačić JK, Nikolić L, Stanković DM, Opačić M, Dimitrijević M, Savić D, Šipka SG, Spasojević I, Pristov JB. Ferrous iron binding to epinephrine promotes the oxidation of iron and impedes activation of adrenergic receptors. Free Radic Biol Med 2020; 148:123-127. [PMID: 31911148 DOI: 10.1016/j.freeradbiomed.2020.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 12/27/2019] [Accepted: 01/01/2020] [Indexed: 11/16/2022]
Abstract
Upon release in response to stress, epinephrine (Epi) may interact with labile iron pool in human plasma with potentially important (patho)physiological consequences. We have shown that Epi and Fe3+ build stable 1:1 high-spin bidentate complex at physiological pH, and that Epi does not undergo degradation in the presence of iron. However, the interactions of Epi with the more soluble Fe2+, and the impact of iron on biological activity of Epi are still not known. Herein we showed that Epi and Fe2+ build colorless complex which is stable under anaerobic conditions. In the presence of O2, Epi promoted the oxidation of Fe2+ and the formation of Epi-Fe3+ complex. Cyclic voltammetry showed that mid-point potential of Epi-Fe2+ complex is very low (-582 mV vs. standard hydrogen electrode), which explains catalyzed oxidation of Fe2+. Next, we examined the impact of iron binding on biological performance of Epi using patch clamping in cell culture with constitutive expression of adrenergic receptors. Epi alone evoked an increase of outward currents, whereas Epi in the complex with Fe3+ did not. This implies that the binding of Epi to adrenergic receptors and their activation is prevented by the formation of complex with iron. Pro-oxidative activity of Epi-Fe2+ complex may represent a link between chronic stress and cardiovascular problems. On the other hand, labile iron could serve as a modulator of biological activity of ligands. Such interactions may be important in human pathologies that are related to iron overload or deficiency.
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Affiliation(s)
- Jelena Korać Jačić
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, 11030 Belgrade, Serbia
| | - Ljiljana Nikolić
- Institute for Biological Research 'Siniša Stanković', University of Belgrade, 11000 Belgrade, Serbia
| | - Dalibor M Stanković
- Vinča Institute of Nuclear Sciences, University of Belgrade, 11000 Belgrade, Serbia
| | - Miloš Opačić
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, 11030 Belgrade, Serbia
| | - Milena Dimitrijević
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, 11030 Belgrade, Serbia
| | - Danijela Savić
- Institute for Biological Research 'Siniša Stanković', University of Belgrade, 11000 Belgrade, Serbia
| | | | - Ivan Spasojević
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, 11030 Belgrade, Serbia.
| | - Jelena Bogdanović Pristov
- Department of Life Sciences, Institute for Multidisciplinary Research, University of Belgrade, 11030 Belgrade, Serbia
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17
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Regional iron distribution and soluble ferroprotein profiles in the healthy human brain. Prog Neurobiol 2019; 186:101744. [PMID: 31870805 DOI: 10.1016/j.pneurobio.2019.101744] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 12/11/2019] [Accepted: 12/18/2019] [Indexed: 12/25/2022]
Abstract
Iron is essential for brain development and health where its redox properties are used for a number of neurological processes. However, iron is also a major driver of oxidative stress if not properly controlled. Brain iron distribution is highly compartmentalised and regulated by a number of proteins and small biomolecules. Here, we examine heterogeneity in regional iron levels in 10 anatomical structures from seven post-mortem human brains with no apparent neuropathology. Putamen contained the highest levels, and most case-to-case variability, of iron compared with the other regions examined. Partitioning of iron between cytosolic and membrane-bound iron was generally consistent in each region, with a slightly higher proportion (55 %) in the 'insoluble' phase. We expand on this using the Allen Human Brain Atlas to examine patterns between iron levels and transcriptomic expression of iron regulatory proteins and using quantitative size exclusion chromatography-inductively coupled plasma-mass spectrometry to assess regional differences in the molecular masses to which cytosolic iron predominantly binds. Approximately 60 % was associated with ferritin, equating to approximately 25 % of total tissue iron essentially in storage. This study is the first of its kind in human brain tissue, providing a valuable resource and new insight for iron biologists and neuroscientists, alike.
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18
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Dziuba N, Hardy J, Lindahl PA. Low-molecular-mass iron complexes in blood plasma of iron-deficient pigs do not originate directly from nutrient iron. Metallomics 2019; 11:1900-1911. [PMID: 31603444 PMCID: PMC6854301 DOI: 10.1039/c9mt00152b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Nutrient iron entering the blood binds transferrin (TFN)d, which delivers iron to cells in the body. In healthy individuals, ∼30% of TFN is iron-bound while the remainder is unbound (apo-TFN). TFN saturates the plasma of individuals with iron-overload diseases such as hereditary hemochromatosis, prompting release of a poorly-defined low-molecular-mass (LMM) iron species called non-transferrin-bound iron (NTBI). An experiment was devised to directly detect NTBI in plasma of iron-deficient pigs and to assess the role of the liver which is known to bind NTBI. Catheters were surgically installed in the portal vein (PV) and either the caudal vena cava or the cranial vena cava. After the animals recovered, 57Fe II ascorbate was injected into the stomach via a feeding tube. Blood was removed through the catheters before and after injection; plasma became 57Fe-enriched after injection. 57Fe-enriched plasma was passed through a 10 kDa cutoff membrane and the flow-through solution (FTS) was subjected to size-exclusion liquid chromatography (LC). The eluent flowed into an ICP-MS where 56Fe and 57Fe were detected. Low-intensity iron peaks with masses of 400-1600 Da were observed, but none became enriched in 57Fe after injection. Rather, the injected 57Fe bound to apo-TFN. Viewed naively, this implies that nutrient-derived 57Fe in healthy mammals passes from the intestines to apo-TFN without first entering the blood as a LMM intermediate. In this case, nutrient iron exported from intestinal enterocytes of healthy individuals may quickly bind apo-TFN such that LMM iron species do not accumulate in blood plasma. Some 57Fe from the FTS may have adsorbed onto the column. In any event, the LMM iron species in plasma that eluted from the column must have originated from iron stored within the body, perhaps in macrophages - not directly from nutrient iron absorption. The liver absorbed and released LMM iron species, but the effect was modest, consistent with its role as a dynamic iron buffer. Passage through the liver also altered the distribution of different forms of TFN present in the PV.
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Affiliation(s)
- Nathaniel Dziuba
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Joanne Hardy
- Department of Veterinary Surgery, Veterinary Medicine and Biosciences, College Station, TX 77843-4475, USA
| | - Paul A Lindahl
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA and Department of Chemistry, Texas A&M University, College Station, TX 77843-3255, USA.
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19
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Guttmann S, Dewald ET, Wohlfarth C, Müller JC, Karst U, Schmidt HH, Zibert A. Compound-specific adaptation of hepatoma cell lines to toxic iron. Metallomics 2019; 11:1836-1846. [PMID: 31552988 DOI: 10.1039/c9mt00202b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cellular adaptation to excess iron (Fe) is a major determinant to protect tissues from toxicity. The adaptation of hepatoma cell lines following exposure to toxic levels of Fe compounds was studied. A dose- and time-dependent induction of toxicity was observed that was strictly compound-specific. Similar ranging orders of toxicity, i.e. iron chloride >iron sulfate >iron citrate, were observed in four human hepatoma cell lines. Long-term cultivation of HepG2 cells in 10 mM iron citrate resulted in a resistant cell line that displayed high proliferation rates for several months. Resistant cells showed increased viability at iron citrate concentrations ranging from 5-15 mM, while exposition to iron chloride or iron sulfate induced high rates of toxicity similar to parental cells. Resistance was not due to decreased Fe uptake/storage since high intracellular Fe levels were observed. A broad range of modulated gene expression was associated with short- and long-term iron citrate exposition; however, after weaning of resistant cells, re-exposition to Fe induced a similar level of toxicity as observed in parental cells suggesting that a transient adaptation of gene expression was mounted. The results indicate that, depending on the nature of the Fe compound, a specific level of toxicity is induced in hepatic cells which however can be overcome by establishment of resistance.
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Affiliation(s)
- Sarah Guttmann
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, Gebäude A14, 48149 Münster, Germany.
| | - Elisabeth Therese Dewald
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, Gebäude A14, 48149 Münster, Germany.
| | - Cathrin Wohlfarth
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, Gebäude A14, 48149 Münster, Germany.
| | | | - Uwe Karst
- Institute of Inorganic and Analytical Chemistry, University of Münster, Münster, Germany
| | - Hartmut H Schmidt
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, Gebäude A14, 48149 Münster, Germany.
| | - Andree Zibert
- Medizinische Klinik B für Gastroenterologie und Hepatologie, Universitätsklinikum Münster, Albert-Schweitzer-Campus 1, Gebäude A14, 48149 Münster, Germany.
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20
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Levina A, Lay PA. Transferrin Cycle and Clinical Roles of Citrate and Ascorbate in Improved Iron Metabolism. ACS Chem Biol 2019; 14:893-900. [PMID: 30973710 DOI: 10.1021/acschembio.8b01100] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Fe(III) delivery from blood plasma to cells via the transferrin (Tf) cycle was studied intensively due to its crucial role in Fe homeostasis. Tf-cycle disruptions are linked to anemia, infections, immunodeficiency, and neurodegeneration. Biolayer interferometry (BLI) enabled direct kinetic and thermodynamic measurements for all Tf-cycle steps in a single in vitro experiment using Tf within blood serum or released into the medium by cultured liver cells. In these media, known Tf cycle features were reproduced, and unprecedented insights were gained into conditions of rapid endosomal (pH 5.6) Fe(III) release from the Tf-Tf receptor 1 (TfR1) adduct. This release occurred via synergistic citrate and ascorbate effects, which pointed to respective roles as the likely elusive Fe chelator and reductant within the Tf cycle. These results explain enhanced cellular Fe uptake by ascorbate, the clinical efficacy of anemia treatment with Fe citrate and ascorbate, and dietary effects associated with loss of Fe homeostasis, including the large health burden of infections and neurodegeneration.
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Affiliation(s)
- Aviva Levina
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
| | - Peter A. Lay
- School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia
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21
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DeGregorio-Rocasolano N, Martí-Sistac O, Gasull T. Deciphering the Iron Side of Stroke: Neurodegeneration at the Crossroads Between Iron Dyshomeostasis, Excitotoxicity, and Ferroptosis. Front Neurosci 2019; 13:85. [PMID: 30837827 PMCID: PMC6389709 DOI: 10.3389/fnins.2019.00085] [Citation(s) in RCA: 92] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2018] [Accepted: 01/25/2019] [Indexed: 12/21/2022] Open
Abstract
In general, iron represents a double-edged sword in metabolism in most tissues, especially in the brain. Although the high metabolic demands of brain cells require iron as a redox-active metal for ATP-producing enzymes, the brain is highly vulnerable to the devastating consequences of excessive iron-induced oxidative stress and, as recently found, to ferroptosis as well. The blood-brain barrier (BBB) protects the brain from fluctuations in systemic iron. Under pathological conditions, especially in acute brain pathologies such as stroke, the BBB is disrupted, and iron pools from the blood gain sudden access to the brain parenchyma, which is crucial in mediating stroke-induced neurodegeneration. Each brain cell type reacts with changes in their expression of proteins involved in iron uptake, efflux, storage, and mobilization to preserve its internal iron homeostasis, with specific organelles such as mitochondria showing specialized responses. However, during ischemia, neurons are challenged with excess extracellular glutamate in the presence of high levels of extracellular iron; this causes glutamate receptor overactivation that boosts neuronal iron uptake and a subsequent overproduction of membrane peroxides. This glutamate-driven neuronal death can be attenuated by iron-chelating compounds or free radical scavenger molecules. Moreover, vascular wall rupture in hemorrhagic stroke results in the accumulation and lysis of iron-rich red blood cells at the brain parenchyma and the subsequent presence of hemoglobin and heme iron at the extracellular milieu, thereby contributing to iron-induced lipid peroxidation and cell death. This review summarizes recent progresses made in understanding the ferroptosis component underlying both ischemic and hemorrhagic stroke subtypes.
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Affiliation(s)
- Núria DeGregorio-Rocasolano
- Cellular and Molecular Neurobiology Research Group, Department of Neurosciences, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
| | - Octavi Martí-Sistac
- Cellular and Molecular Neurobiology Research Group, Department of Neurosciences, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain.,Department of Cellular Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Bellaterra, Spain
| | - Teresa Gasull
- Cellular and Molecular Neurobiology Research Group, Department of Neurosciences, Germans Trias i Pujol Research Institute (IGTP), Badalona, Spain
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22
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Neu HM, Alexishin SA, Brandis JEP, Williams AMC, Li W, Sun D, Zheng N, Jiang W, Zimrin A, Fink JC, Polli JE, Kane MA, Michel SLJ. Snapshots of Iron Speciation: Tracking the Fate of Iron Nanoparticle Drugs via a Liquid Chromatography-Inductively Coupled Plasma-Mass Spectrometric Approach. Mol Pharm 2019; 16:1272-1281. [PMID: 30676753 DOI: 10.1021/acs.molpharmaceut.8b01215] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Nanomedicines are nanoparticle-based therapeutic or diagnostic agents designed for targeted delivery or enhanced stability. Nanotechnology has been successfully employed to develop various drug formulations with improved pharmacokinetic characteristics, and current research efforts are focused on the development of new innovator and generic nanomedicines. Nanomedicines, which are often denoted as complex or nonbiological complex drugs, have inherently different physicochemical and pharmacokinetic properties than conventional small molecule drugs. The tools necessary to fully evaluate nanomedicines in clinical settings are limited, which can hamper their development. One of the most successful families of nanomedicines are iron-carbohydrate nanoparticles, which are administered intravenously (IV) to treat iron-deficiency anemia. In the U.S., the FDA has approved six distinct iron-carbohydrate nanoparticles but only one generic version (sodium ferric gluconate for Ferrlecit). There is significant interest in approving additional generic iron-carbohydrate drugs; however, the lack of a direct method to monitor the fate of the iron nanoparticles in clinical samples has impeded this approval. Herein we report a novel liquid chromatography-inductively coupled plasma-mass spectrometry (LC-ICP-MS) method that allows for the direct quantification of the iron-carbohydrate drugs in clinical samples, while simultaneously measuring the speciation of the iron released from the nanoparticles in biological samples. To our knowledge, this is the first time that iron nanoparticles have been observed in clinical samples, opening the door for direct pharmacokinetic studies of this family of drugs. This method has potential applications not only for iron-nanoparticle drugs but also for any nanomedicine with an inorganic component.
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Affiliation(s)
- Heather M Neu
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Sergei A Alexishin
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Joel E P Brandis
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Anne M C Williams
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Wenjing Li
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Dajun Sun
- Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research , U.S. Food and Drug Administration , Silver Spring , Maryland 20993 , United States
| | - Nan Zheng
- Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research , U.S. Food and Drug Administration , Silver Spring , Maryland 20993 , United States
| | - Wenlei Jiang
- Office of Research and Standards, Office of Generic Drugs, Center for Drug Evaluation and Research , U.S. Food and Drug Administration , Silver Spring , Maryland 20993 , United States
| | - Ann Zimrin
- Oncology Program , University of Maryland School of Medicine , Baltimore , Maryland 21201 , United States
| | - Jeffrey C Fink
- Department of Medicine , University of Maryland School of Medicine , Baltimore , Maryland 21201 , United States
| | - James E Polli
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Maureen A Kane
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
| | - Sarah L J Michel
- Department of Pharmaceutical Sciences , University of Maryland School of Pharmacy , Baltimore , Maryland 21201 , United States
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23
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Wofford JD, Bolaji N, Dziuba N, Outten FW, Lindahl PA. Evidence that a respiratory shield in Escherichia coli protects a low-molecular-mass Fe II pool from O 2-dependent oxidation. J Biol Chem 2018; 294:50-62. [PMID: 30337367 DOI: 10.1074/jbc.ra118.005233] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 10/16/2018] [Indexed: 11/06/2022] Open
Abstract
Iron is critical for virtually all organisms, yet major questions remain regarding the systems-level understanding of iron in whole cells. Here, we obtained Mössbauer and EPR spectra of Escherichia coli cells prepared under different nutrient iron concentrations, carbon sources, growth phases, and O2 concentrations to better understand their global iron content. We investigated WT cells and those lacking Fur, FtnA, Bfr, and Dps proteins. The coarse-grain iron content of exponentially growing cells consisted of iron-sulfur clusters, variable amounts of nonheme high-spin FeII species, and an unassigned residual quadrupole doublet. The iron in stationary-phase cells was dominated by magnetically ordered FeIII ions due to oxyhydroxide nanoparticles. Analysis of cytosolic extracts by size-exclusion chromatography detected by an online inductively coupled plasma mass spectrometer revealed a low-molecular-mass (LMM) FeII pool consisting of two iron complexes with masses of ∼500 (major) and ∼1300 (minor) Da. They appeared to be high-spin FeII species with mostly oxygen donor ligands, perhaps a few nitrogen donors, and probably no sulfur donors. Surprisingly, the iron content of E. coli and its reactivity with O2 were remarkably similar to those of mitochondria. In both cases, a "respiratory shield" composed of membrane-bound iron-rich respiratory complexes may protect the LMM FeII pool from reacting with O2 When exponentially growing cells transition to stationary phase, the shield deactivates as metabolic activity declines. Given the universality of oxidative phosphorylation in aerobic biology, the iron content and respiratory shield in other aerobic prokaryotes might be similar to those of E. coli and mitochondria.
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Affiliation(s)
- Joshua D Wofford
- Department of Chemistry, Texas A&M University, College Station, Texas 77843
| | - Naimah Bolaji
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Nathaniel Dziuba
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843
| | - F Wayne Outten
- Department of Chemistry and Biochemistry, University of South Carolina, Columbia, South Carolina 29208
| | - Paul A Lindahl
- Department of Chemistry, Texas A&M University, College Station, Texas 77843; Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77843.
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