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Płonka D, Wiśniewska MD, Peris-Díaz MD, Krężel A, Bonna AM, Bal W. An Overlooked Hepcidin-Cadmium Connection. Int J Mol Sci 2022; 23:ijms232415483. [PMID: 36555126 PMCID: PMC9779829 DOI: 10.3390/ijms232415483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 12/03/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022] Open
Abstract
Hepcidin (DTHFPICIFCCGCCHRSKCGMCCKT), an iron-regulatory hormone, is a 25-amino-acid peptide with four intramolecular disulfide bonds circulating in blood. Its hormonal activity is indirect and consists of marking ferroportin-1 (an iron exporter) for degradation. Hepcidin biosynthesis involves the N-terminally extended precursors prepro-hepcidin and pro-hepcidin, processed by peptidases to the final 25-peptide form. A sequence-specific formation of disulfide bonds and export of the oxidized peptide to the bloodstream follows. In this study we considered the fact that prior to export, reduced hepcidin may function as an octathiol ligand bearing some resemblance to the N-terminal part of the α-domain of metallothioneins. Consequently, we studied its ability to bind Zn(II) and Cd(II) ions using the original peptide and a model for prohepcidin extended N-terminally with a stretch of five arginine residues (5R-hepcidin). We found that both form equivalent mononuclear complexes with two Zn(II) or Cd(II) ions saturating all eight Cys residues. The average affinity at pH 7.4, determined from pH-metric spectroscopic titrations, is 1010.1 M-1 for Zn(II) ions; Cd(II) ions bind with affinities of 1015.2 M-1 and 1014.1 M-1. Using mass spectrometry and 5R-hepcidin we demonstrated that hepcidin can compete for Cd(II) ions with metallothionein-2, a cellular cadmium target. This study enabled us to conclude that hepcidin binds Zn(II) and Cd(II) sufficiently strongly to participate in zinc physiology and cadmium toxicity under intracellular conditions.
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Affiliation(s)
- Dawid Płonka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Marta D. Wiśniewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Manuel D. Peris-Díaz
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Artur Krężel
- Department of Chemical Biology, Faculty of Biotechnology, University of Wrocław, Joliot-Curie 14a, 50-383 Wrocław, Poland
| | - Arkadiusz M. Bonna
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
| | - Wojciech Bal
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawińskiego 5a, 02-106 Warsaw, Poland
- Correspondence:
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2
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Probst S, Fels J, Scharner B, Wolff NA, Roussa E, van Swelm RPL, Lee WK, Thévenod F. Role of hepcidin in oxidative stress and cell death of cultured mouse renal collecting duct cells: protection against iron and sensitization to cadmium. Arch Toxicol 2021; 95:2719-2735. [PMID: 34181029 PMCID: PMC8298330 DOI: 10.1007/s00204-021-03106-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 06/17/2021] [Indexed: 11/05/2022]
Abstract
The liver hormone hepcidin regulates systemic iron homeostasis. Hepcidin is also expressed by the kidney, but exclusively in distal nephron segments. Several studies suggest hepcidin protects against kidney damage involving Fe2+ overload. The nephrotoxic non-essential metal ion Cd2+ can displace Fe2+ from cellular biomolecules, causing oxidative stress and cell death. The role of hepcidin in Fe2+ and Cd2+ toxicity was assessed in mouse renal cortical [mCCD(cl.1)] and inner medullary [mIMCD3] collecting duct cell lines. Cells were exposed to equipotent Cd2+ (0.5-5 μmol/l) and/or Fe2+ (50-100 μmol/l) for 4-24 h. Hepcidin (Hamp1) was transiently silenced by RNAi or overexpressed by plasmid transfection. Hepcidin or catalase expression were evaluated by RT-PCR, qPCR, immunoblotting or immunofluorescence microscopy, and cell fate by MTT, apoptosis and necrosis assays. Reactive oxygen species (ROS) were detected using CellROX™ Green and catalase activity by fluorometry. Hepcidin upregulation protected against Fe2+-induced mIMCD3 cell death by increasing catalase activity and reducing ROS, but exacerbated Cd2+-induced catalase dysfunction, increasing ROS and cell death. Opposite effects were observed with Hamp1 siRNA. Similar to Hamp1 silencing, increased intracellular Fe2+ prevented Cd2+ damage, ROS formation and catalase disruption whereas chelation of intracellular Fe2+ with desferrioxamine augmented Cd2+ damage, corresponding to hepcidin upregulation. Comparable effects were observed in mCCD(cl.1) cells, indicating equivalent functions of renal hepcidin in different collecting duct segments. In conclusion, hepcidin likely binds Fe2+, but not Cd2+. Because Fe2+ and Cd2+ compete for functional binding sites in proteins, hepcidin affects their free metal ion pools and differentially impacts downstream processes and cell fate.
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Affiliation(s)
- Stephanie Probst
- Faculty of Health, Institute of Physiology, Pathophysiology and Toxicology and ZBAF (Centre for Biomedical Education and Research), School of Medicine, Witten/Herdecke University, Stockumer Str 12 (Thyssenhaus), 58453, Witten, Germany
| | - Johannes Fels
- Faculty of Health, Institute of Physiology, Pathophysiology and Toxicology and ZBAF (Centre for Biomedical Education and Research), School of Medicine, Witten/Herdecke University, Stockumer Str 12 (Thyssenhaus), 58453, Witten, Germany
| | - Bettina Scharner
- Faculty of Health, Institute of Physiology, Pathophysiology and Toxicology and ZBAF (Centre for Biomedical Education and Research), School of Medicine, Witten/Herdecke University, Stockumer Str 12 (Thyssenhaus), 58453, Witten, Germany
| | - Natascha A Wolff
- Faculty of Health, Institute of Physiology, Pathophysiology and Toxicology and ZBAF (Centre for Biomedical Education and Research), School of Medicine, Witten/Herdecke University, Stockumer Str 12 (Thyssenhaus), 58453, Witten, Germany
| | - Eleni Roussa
- Department of Molecular Embryology, Faculty of Medicine, Institute of Anatomy and Cell Biology, University of Freiburg, Albertstr. 17, 79104, Freiburg, Germany
| | - Rachel P L van Swelm
- Department of Laboratory Medicine, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Geert Grooteplein 10, 6525 GA, Nijmegen, The Netherlands
| | - Wing-Kee Lee
- Faculty of Health, Institute of Physiology, Pathophysiology and Toxicology and ZBAF (Centre for Biomedical Education and Research), School of Medicine, Witten/Herdecke University, Stockumer Str 12 (Thyssenhaus), 58453, Witten, Germany
- AG Physiology and Pathophysiology of Cells and Membranes, Medical School OWL, Bielefeld University, Morgenbreede 1, 33615, Bielefeld, Germany
| | - Frank Thévenod
- Faculty of Health, Institute of Physiology, Pathophysiology and Toxicology and ZBAF (Centre for Biomedical Education and Research), School of Medicine, Witten/Herdecke University, Stockumer Str 12 (Thyssenhaus), 58453, Witten, Germany.
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Moulis JM. Cellular Dynamics of Transition Metal Exchange on Proteins: A Challenge but a Bonanza for Coordination Chemistry. Biomolecules 2020; 10:E1584. [PMID: 33233467 PMCID: PMC7700505 DOI: 10.3390/biom10111584] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 12/19/2022] Open
Abstract
Transition metals interact with a large proportion of the proteome in all forms of life, and they play mandatory and irreplaceable roles. The dynamics of ligand binding to ions of transition metals falls within the realm of Coordination Chemistry, and it provides the basic principles controlling traffic, regulation, and use of metals in cells. Yet, the cellular environment stands out against the conditions prevailing in the test tube when studying metal ions and their interactions with various ligands. Indeed, the complex and often changing cellular environment stimulates fast metal-ligand exchange that mostly escapes presently available probing methods. Reducing the complexity of the problem with purified proteins or in model organisms, although useful, is not free from pitfalls and misleading results. These problems arise mainly from the absence of the biosynthetic machinery and accessory proteins or chaperones dealing with metal / metal groups in cells. Even cells struggle with metal selectivity, as they do not have a metal-directed quality control system for metalloproteins, and serendipitous metal binding is probably not exceptional. The issue of metal exchange in biology is reviewed with particular reference to iron and illustrating examples in patho-physiology, regulation, nutrition, and toxicity.
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Affiliation(s)
- Jean-Marc Moulis
- Alternative Energies and Atomic Energy Commission—Fundamental Research Division—Interdisciplinary Research Institute of Grenoble (CEA-IRIG), University of Grenoble Alpes, F-38000 Grenoble, France;
- National Institute of Health and Medical Research, University of Grenoble Alpes, Inserm U1055, F-38000 Grenoble, France
- Laboratory of Fundamental and Applied Bioenergetics (LBFA), University of Grenoble Alpes, Inserm U1055, F-38000 Grenoble, France
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4
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Mehta KJ, Busbridge M, Patel VB, Farnaud SJ. Hepcidin secretion was not directly proportional to intracellular iron-loading in recombinant-TfR1 HepG2 cells: short communication. Mol Cell Biochem 2020; 468:121-128. [PMID: 32185675 PMCID: PMC7145775 DOI: 10.1007/s11010-020-03716-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 03/06/2020] [Indexed: 02/08/2023]
Abstract
Hepcidin is the master regulator of systemic iron homeostasis and its dysregulation is observed in several chronic liver diseases. Unlike the extracellular iron-sensing mechanisms, the intracellular iron-sensing mechanisms in the hepatocytes that lead to hepcidin induction and secretion are incompletely understood. Here, we aimed to understand the direct role of intracellular iron-loading on hepcidin mRNA and peptide secretion using our previously characterised recombinant HepG2 cells that over-express the cell-surface iron-importer protein transferrin receptor-1. Gene expression of hepcidin (HAMP) was determined by real-time PCR. Intracellular iron levels and secreted hepcidin peptide levels were measured by ferrozine assay and immunoassay, respectively. These measurements were compared in the recombinant and wild-type HepG2 cells under basal conditions at 30 min, 2 h, 4 h and 24 h. Data showed that in the recombinant cells, intracellular iron content was higher than wild-type cells at 30 min (3.1-fold, p < 0.01), 2 h (4.6-fold, p < 0.01), 4 h (4.6-fold, p < 0.01) and 24 h (1.9-fold, p < 0.01). Hepcidin (HAMP) mRNA expression was higher than wild-type cells at 30 min (5.9-fold; p = 0.05) and 24 h (6.1-fold; p < 0.03), but at 4 h, the expression was lower than that in wild-type cells (p < 0.05). However, hepcidin secretion levels in the recombinant cells were similar to those in wild-type cells at all time-points, except at 4 h, when the level was lower than wild-type cells (p < 0.01). High intracellular iron in recombinant HepG2 cells did not proportionally increase hepcidin peptide secretion. This suggests a limited role of elevated intracellular iron in hepcidin secretion.
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Affiliation(s)
- Kosha J Mehta
- Centre for Education, Faculty of Life Sciences and Medicine, King's College London, London, UK.
- School of Life Sciences, University of Westminster, London, UK.
| | - Mark Busbridge
- Department of Clinical Biochemistry, Northwest London Pathology, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Vinood B Patel
- School of Life Sciences, University of Westminster, London, UK
| | - Sebastien Je Farnaud
- Centre for Sport, Exercise and Life Sciences, Faculty of Health & Life Sciences, Coventry University, Coventry, UK
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5
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Malyszko J, Bachorzewska-Gajewska H, Malyszko JS, Koc-Zorawska E, Matuszkiewicz-Rowinska J, Dobrzycki S. Hepcidin - Potential biomarker of contrast-induced acute kidney injury in patients undergoing percutaneous coronary interventions. Adv Med Sci 2019; 64:211-215. [PMID: 30818219 DOI: 10.1016/j.advms.2018.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2018] [Revised: 10/10/2018] [Accepted: 12/18/2018] [Indexed: 11/24/2022]
Abstract
PURPOSE Contrast-induced acute kidney injury (CI-AKI) is a common and potentially serious complication of percutaneous coronary interventions (PCI). In this study, we tested the hypothesis whether serum and urinary hepcidin could represent early biomarkers of CI-AKI in patients with normal serum creatinine undergoing PCI. In addition, we assessed serum and urinary neutrophil gelatinase-associated lipocalin (NGAL), cystatin C, eGFR and serum creatinine in these patients. METHODS Serum and urinary hepcidin and NGAL, serum cystatin C, were evaluated before, and after 2, 4, 8, 24 and 48 h after PCI using commercially available kits. Serum creatinine was assessed before, 24 and 48 h after PCI. RESULTS We found a significant rise in serum hepcidin as early as after 4 and 8 h when compared to the baseline values. Serum NGAL increased after 2, 4 and 8 h, and in urinary NGAL after 4, 8 and 24 h after PCI. We found a significant fall in urinary hepcidin after 8 and 24 h after PCI. Serum cystatin C increased significantly 8 h after PCI, reaching peak 24 h after PCI and then decreased after 48 h. The prevalence of CI-AKI was 8%. Urine hepcidin was significantly lower 8 and 24 h after PCI in patients with CI-AKI, while serum and urine NGAL were significantly higher in patients with CI-AKI. CONCLUSIONS Our findings suggest that serum hepcidin might be an early predictive biomarker of ruling out CI-AKI after PCI, thereby contributing to early patient risk stratification. However, our data needs to be validated in large cohorts with various stages of CKD.
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Van Avondt K, Nur E, Zeerleder S. Mechanisms of haemolysis-induced kidney injury. Nat Rev Nephrol 2019; 15:671-692. [PMID: 31455889 DOI: 10.1038/s41581-019-0181-0] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/10/2019] [Indexed: 12/16/2022]
Abstract
Intravascular haemolysis is a fundamental feature of chronic hereditary and acquired haemolytic anaemias, including those associated with haemoglobinopathies, complement disorders and infectious diseases such as malaria. Destabilization of red blood cells (RBCs) within the vasculature results in systemic inflammation, vasomotor dysfunction, thrombophilia and proliferative vasculopathy. The haemoprotein scavengers haptoglobin and haemopexin act to limit circulating levels of free haemoglobin, haem and iron - potentially toxic species that are released from injured RBCs. However, these adaptive defence systems can fail owing to ongoing intravascular disintegration of RBCs. Induction of the haem-degrading enzyme haem oxygenase 1 (HO1) - and potentially HO2 - represents a response to, and endogenous defence against, large amounts of cellular haem; however, this system can also become saturated. A frequent adverse consequence of massive and/or chronic haemolysis is kidney injury, which contributes to the morbidity and mortality of chronic haemolytic diseases. Intravascular destruction of RBCs and the resulting accumulation of haemoproteins can induce kidney injury via a number of mechanisms, including oxidative stress and cytotoxicity pathways, through the formation of intratubular casts and through direct as well as indirect proinflammatory effects, the latter via the activation of neutrophils and monocytes. Understanding of the detailed pathophysiology of haemolysis-induced kidney injury offers opportunities for the design and implementation of new therapeutic strategies to counteract the unfavourable and potentially fatal effects of haemolysis on the kidney.
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Affiliation(s)
- Kristof Van Avondt
- Department of Immunopathology, Sanquin Research, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands. .,Institute for Cardiovascular Prevention (IPEK), Ludwig Maximilian University of Munich, Munich, Germany.
| | - Erfan Nur
- Department of Haematology, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands
| | - Sacha Zeerleder
- Department of Immunopathology, Sanquin Research, and Landsteiner Laboratory, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands. .,Department of Haematology and Central Haematology Laboratory, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland. .,Department for BioMedical Research, University of Bern, Bern, Switzerland.
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7
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8
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Abbas IM, Vranic M, Hoffmann H, El-Khatib AH, Montes-Bayón M, Möller HM, Weller MG. Investigations of the Copper Peptide Hepcidin-25 by LC-MS/MS and NMR. Int J Mol Sci 2018; 19:E2271. [PMID: 30072660 PMCID: PMC6121404 DOI: 10.3390/ijms19082271] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2018] [Revised: 07/06/2018] [Accepted: 07/20/2018] [Indexed: 01/19/2023] Open
Abstract
Hepcidin-25 was identified as the main iron regulator in the human body, and it by binds to the sole iron-exporter ferroportin. Studies showed that the N-terminus of hepcidin is responsible for this interaction, the same N-terminus that encompasses a small copper(II)-binding site known as the ATCUN (amino-terminal Cu(II)- and Ni(II)-binding) motif. Interestingly, this copper-binding property is largely ignored in most papers dealing with hepcidin-25. In this context, detailed investigations of the complex formed between hepcidin-25 and copper could reveal insight into its biological role. The present work focuses on metal-bound hepcidin-25 that can be considered the biologically active form. The first part is devoted to the reversed-phase chromatographic separation of copper-bound and copper-free hepcidin-25 achieved by applying basic mobile phases containing 0.1% ammonia. Further, mass spectrometry (tandem mass spectrometry (MS/MS), high-resolution mass spectrometry (HRMS)) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterize the copper-peptide. Lastly, a three-dimensional (3D) model of hepcidin-25 with bound copper(II) is presented. The identification of metal complexes and potential isoforms and isomers, from which the latter usually are left undetected by mass spectrometry, led to the conclusion that complementary analytical methods are needed to characterize a peptide calibrant or reference material comprehensively. Quantitative nuclear magnetic resonance (qNMR), inductively-coupled plasma mass spectrometry (ICP-MS), ion-mobility spectrometry (IMS) and chiral amino acid analysis (AAA) should be considered among others.
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Affiliation(s)
- Ioana M Abbas
- Federal Institute for Materials Research and Testing (BAM), Division 1.5 Protein Analysis, Richard-Willstätter-Strasse 11, 12489 Berlin, Germany.
- School of Analytical Sciences Adlershof, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany.
| | - Marija Vranic
- Federal Institute for Materials Research and Testing (BAM), Division 1.5 Protein Analysis, Richard-Willstätter-Strasse 11, 12489 Berlin, Germany.
- School of Analytical Sciences Adlershof, Humboldt-Universität zu Berlin, Unter den Linden 6, 10099 Berlin, Germany.
- Institute of Chemistry/Analytical Chemistry, University of Potsdam, 14476 Potsdam, Germany.
| | - Holger Hoffmann
- Federal Institute for Materials Research and Testing (BAM), Division 1.8 Environmental Analysis, Richard-Willstätter-Strasse 11, 12489 Berlin, Germany.
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin, Germany.
| | - Ahmed H El-Khatib
- Federal Institute for Materials Research and Testing (BAM), Division 1.1 Inorganic Trace Analysis, Richard-Willstätter-Strasse 11, 12489 Berlin, Germany.
- Department of Pharmaceutical Analytical Chemistry, Faculty of Pharmacy, Ain Shams University, 11566 Cairo, Egypt.
| | - María Montes-Bayón
- Department of Physical and Analytical Chemistry, University of Oviedo, C/Julian Claveria 8, 33006 Oviedo, Spain.
| | - Heiko M Möller
- Institute of Chemistry/Analytical Chemistry, University of Potsdam, 14476 Potsdam, Germany.
| | - Michael G Weller
- Federal Institute for Materials Research and Testing (BAM), Division 1.5 Protein Analysis, Richard-Willstätter-Strasse 11, 12489 Berlin, Germany.
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9
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van Swelm RPL, Vos M, Verhoeven F, Thévenod F, Swinkels DW. Endogenous hepcidin synthesis protects the distal nephron against hemin and hemoglobin mediated necroptosis. Cell Death Dis 2018; 9:550. [PMID: 29749404 PMCID: PMC5945780 DOI: 10.1038/s41419-018-0568-z] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Revised: 03/30/2018] [Accepted: 04/06/2018] [Indexed: 12/11/2022]
Abstract
Hemoglobinuria is associated with kidney injury in various hemolytic pathologies. Currently, there is no treatment available and its pathophysiology is not completely understood. Here we studied the potential detrimental effects of hemoglobin (Hb) exposure to the distal nephron (DN). Involvement of the DN in Hb kidney injury was suggested by the induction of renal hepcidin synthesis (p < 0.001) in mice repeatedly injected with intravenous Hb. Moreover, the hepcidin induction was associated with a decline in urinary kidney injury markers 24p3/NGAL and KIM1, suggesting a role for hepcidin in protection against Hb kidney injury. We demonstrated that uptake of Hb in the mouse cortical collecting duct cells (mCCDcl1) is mediated by multi-protein ligand receptor 24p3R, as indicated by a significant 90% reduction in Hb uptake (p < 0.001) after 24p3R silencing. Moreover, incubation of mCCDcl1 cells with Hb or hemin for 4 or 24 h resulted in hepcidin synthesis and increased mRNA expression of markers for oxidative, inflammatory and ER stress, but no cell death as indicated by apoptosis staining. A protective role for cellular hepcidin against Hb-induced injury was demonstrated by aggravation of oxidative, inflammatory and ER stress after 4 h Hb or hemin incubation in hepcidin silenced mCCDcl1 cells. Hepcidin silencing potentiated hemin-mediated cell death that could be diminished by co-incubation of Nec-1, suggesting that endogenous hepcidin prevents necroptosis. Combined, these results demonstrate that renal hepcidin synthesis protects the DN against hemin and hemoglobin-mediated injury.
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Affiliation(s)
- Rachel P L van Swelm
- Department of Laboratory Medicine, Radboud university medical center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands.
| | - Madelon Vos
- Department of Laboratory Medicine, Radboud university medical center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Frank Verhoeven
- Department of Laboratory Medicine, Radboud university medical center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Frank Thévenod
- Institute of Physiology, Pathophysiology & Toxicology, Center for Biomedical Training and Research, University of Witten/Herdecke, Witten, Germany
| | - Dorine W Swinkels
- Department of Laboratory Medicine, Radboud university medical center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
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10
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Płonka D, Bal W. The N-terminus of hepcidin is a strong and potentially biologically relevant Cu(II) chelator. Inorganica Chim Acta 2018. [DOI: 10.1016/j.ica.2017.06.051] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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11
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Zhabyeyev P, Das SK, Basu R, Shen M, Patel VB, Kassiri Z, Oudit GY. TIMP3 deficiency exacerbates iron overload-mediated cardiomyopathy and liver disease. Am J Physiol Heart Circ Physiol 2018; 314:H978-H990. [PMID: 29373036 DOI: 10.1152/ajpheart.00597.2017] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chronic iron overload results in heart and liver diseases and is a common cause of morbidity and mortality in patients with genetic hemochromatosis and secondary iron overload. We investigated the role of tissue inhibitor of metalloproteinase 3 (TIMP3) in iron overload-mediated tissue injury by subjecting male mice lacking Timp3 ( Timp3-/-) and wild-type (WT) mice to 12 wk of chronic iron overload. Whereas WT mice with iron overload developed diastolic dysfunction, iron-overloaded Timp3-/- mice showed worsened cardiac dysfunction coupled with systolic dysfunction. In the heart, loss of Timp3 was associated with increased myocardial fibrosis, greater Timp1, matrix metalloproteinase ( Mmp) 2, and Mmp9 expression, increased active MMP-2 levels, and gelatinase activity. Iron overload in Timp3-/- mice showed twofold higher iron accumulation in the liver compared with WT mice because of constituently lower levels of ferroportin. Loss of Timp3 enhanced the hepatic inflammatory response to iron overload, leading to greater neutrophil and macrophage infiltration and increased hepatic fibrosis. Expression of inflammation-related MMPs (MMP-12 and MMP-13) and inflammatory cytokines (IL-1β and monocyte chemoattractant protein-1) was elevated to a greater extent in iron-overloaded Timp3-/- livers. Gelatin zymography demonstrated equivalent increases in MMP-2 and MMP-9 levels in WT and Timp3-/- iron-overloaded livers. Loss of Timp3 enhanced the susceptibility to iron overload-mediated heart and liver injury, suggesting that Timp3 is a key protective molecule against iron-mediated pathology. NEW & NOTEWORTHY In mice, loss of tissue inhibitor of metalloproteinase 3 ( Timp3) was associated with systolic and diastolic dysfunctions, twofold higher hepatic iron accumulation (attributable to constituently lower levels of ferroportin), and increased hepatic inflammation. Loss of Timp3 enhanced the susceptibility to iron overload-mediated injury, suggesting that Timp3 plays a key protective role against iron-mediated pathology.
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Affiliation(s)
- Pavel Zhabyeyev
- Division of Cardiology, Department of Medicine, University of Alberta , Edmonton, Alberta , Canada.,Mazankowski Alberta Heart Institute, University of Alberta , Edmonton, Alberta , Canada
| | - Subhash K Das
- Division of Cardiology, Department of Medicine, University of Alberta , Edmonton, Alberta , Canada.,Mazankowski Alberta Heart Institute, University of Alberta , Edmonton, Alberta , Canada
| | - Ratnadeep Basu
- Division of Cardiology, Department of Medicine, University of Alberta , Edmonton, Alberta , Canada.,Mazankowski Alberta Heart Institute, University of Alberta , Edmonton, Alberta , Canada
| | - Mengcheng Shen
- Department of Physiology, University of Alberta , Edmonton, Alberta , Canada
| | - Vaibhav B Patel
- Division of Cardiology, Department of Medicine, University of Alberta , Edmonton, Alberta , Canada.,Mazankowski Alberta Heart Institute, University of Alberta , Edmonton, Alberta , Canada
| | - Zamaneh Kassiri
- Mazankowski Alberta Heart Institute, University of Alberta , Edmonton, Alberta , Canada.,Department of Physiology, University of Alberta , Edmonton, Alberta , Canada
| | - Gavin Y Oudit
- Division of Cardiology, Department of Medicine, University of Alberta , Edmonton, Alberta , Canada.,Mazankowski Alberta Heart Institute, University of Alberta , Edmonton, Alberta , Canada
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12
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Gama S, Frontauria M, Ueberschaar N, Brancato G, Milea D, Sammartano S, Plass W. Thermodynamic study on 8-hydroxyquinoline-2-carboxylic acid as a chelating agent for iron found in the gut of Noctuid larvae. NEW J CHEM 2018. [DOI: 10.1039/c7nj04889k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
8-HQA is a good sequestering agent towards Fe2+ and Fe3+ over a wide pH range.
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Affiliation(s)
- Sofia Gama
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- 07743 Jena
- Germany
| | - Mariachiara Frontauria
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- 07743 Jena
- Germany
| | - Nico Ueberschaar
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- 07743 Jena
- Germany
| | - Giuseppe Brancato
- Scuola Normale Superiore
- Palazzo della Carovana
- Classe di Scienze Matematiche e Naturali
- Pisa
- Italy
| | - Demetrio Milea
- Dipartimento di Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali
- Università di Messina
- 98166 Messina
| | - Silvio Sammartano
- Dipartimento di Scienze Chimiche
- Biologiche
- Farmaceutiche ed Ambientali
- Università di Messina
- 98166 Messina
| | - Winfried Plass
- Institut für Anorganische und Analytische Chemie
- Friedrich-Schiller-Universität Jena
- 07743 Jena
- Germany
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Mehta K, Busbridge M, Renshaw D, Evans RW, Farnaud S, Patel VB. Characterization of hepcidin response to holotransferrin in novel recombinant TfR1 HepG2 cells. Blood Cells Mol Dis 2016; 61:37-45. [PMID: 27667164 DOI: 10.1016/j.bcmd.2016.06.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Revised: 06/28/2016] [Accepted: 06/28/2016] [Indexed: 12/14/2022]
Abstract
Hepcidin is the key regulator of systemic iron homeostasis. The iron-sensing mechanisms and the role of intracellular iron in modulating hepatic hepcidin secretion are unclear. Therefore, we created a novel cell line, recombinant-TfR1 HepG2, expressing iron-response-element-independent TFRC mRNA to promote cellular iron-overload and examined the effect of excess holotransferrin (5g/L) on cell-surface TfR1, iron content, hepcidin secretion and mRNA expressions of TFRC, HAMP, SLC40A1, HFE and TFR2. Results showed that the recombinant cells exceeded levels of cell-surface TfR1 in wild-type cells under basal (2.8-fold; p<0.03) and holotransferrin-supplemented conditions for 24h and 48h (4.4- and 7.5-fold, respectively; p<0.01). Also, these cells showed higher intracellular iron content than wild-type cells under basal (3-fold; p<0.03) and holotransferrin-supplemented conditions (6.6-fold at 4h; p<0.01). However, hepcidin secretion was not higher than wild-type cells. Moreover, holotransferrin treatment to recombinant cells did not elevate HAMP responses compared to untreated or wild-type cells. In conclusion, increased intracellular iron content in recombinant cells did not increase hepcidin responses compared to wild-type cells, resembling hemochromatosis. Furthermore, TFR2 expression altered within 4h of treatment, while HFE expression altered later at 24h and 48h, suggesting that TFR2 may function prior to HFE in HAMP regulation.
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Affiliation(s)
- Kosha Mehta
- Department of Biomedical Sciences, University of Westminster, London, UK
| | - Mark Busbridge
- Department of Clinical Biochemistry, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London, UK
| | - Derek Renshaw
- Faculty of Health & Life Sciences, Coventry University, Coventry, UK
| | - Robert W Evans
- School of Engineering and Design, Brunel University, London, UK
| | | | - Vinood B Patel
- Department of Biomedical Sciences, University of Westminster, London, UK.
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Structure and mode of action of cyclic lipopeptide pseudofactin II with divalent metal ions. Colloids Surf B Biointerfaces 2016; 146:498-506. [PMID: 27416562 DOI: 10.1016/j.colsurfb.2016.06.055] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2016] [Revised: 06/22/2016] [Accepted: 06/27/2016] [Indexed: 12/21/2022]
Abstract
The interaction of natural lipopeptide pseudofactin II with a series of doubly charged metal cations was examined by matrix-assisted laser-desorption ionization-time of flight (MALDI-TOF) mass spectrometry and molecular modelling. The molecular modelling for metal-pseudofactin II provides information on the metal-peptide binding sites. Overall, Mg(2+), Ca(2+) and Zn(2+) favor the association with oxygen atoms spanning the peptide backbone, whereas Cu(2+) is coordinated by three nitrogens. Circular dichroism (CD) results confirmed that Zn(2+) and Cu(2+) can disrupt the secondary structure of pseudofactin II at high concentrations, while Ca(2+) and Mg(2+) did not essentially affect the structure of the lipopeptide. Interestingly, our results showed that the addition of Zn(2+) and Cu(2+) helped smaller micelles to form larger micellar aggregates. Since pseudofactin II binds metals, we tested whether this phenomena was somehow related to its antimicrobial activity against Staphylococcus epidermidis and Proteus mirabilis. We found that the antimicrobial effect of pseudofactin II was increased by supplementation of culture media with all tested divalent metal ions. Finally, by using Gram-positive and Gram-negative bacteria we showed that the higher antimicrobial activity of metal complexes of pseudofactin II is attributed to the disruption of the cytoplasmic membrane.
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15
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van Swelm RPL, Wetzels JFM, Verweij VGM, Laarakkers CMM, Pertijs JCLM, van der Wijst J, Thévenod F, Masereeuw R, Swinkels DW. Renal Handling of Circulating and Renal-Synthesized Hepcidin and Its Protective Effects against Hemoglobin-Mediated Kidney Injury. J Am Soc Nephrol 2016; 27:2720-32. [PMID: 26825531 DOI: 10.1681/asn.2015040461] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 12/12/2015] [Indexed: 11/03/2022] Open
Abstract
Urinary hepcidin may have protective effects against AKI. However, renal handling and the potential protective mechanisms of hepcidin are not fully understood. By measuring hepcidin levels in plasma and urine using mass spectrometry and the kidney using immunohistochemistry after intraperitoneal administration of human hepcidin-25 (hhep25) in C57Bl/6N mice, we showed that circulating hepcidin is filtered by the glomerulus and degraded to smaller isoforms detected in urine but not plasma. Moreover, hepcidin colocalized with the endocytic receptor megalin in proximal tubules, and compared with wild-type mice, megalin-deficient mice showed higher urinary excretion of injected hhep25 and no hepcidin staining in proximal tubules that lack megalin. This indicates that hepcidin is reaborbed in the proximal tubules by megalin dependent endocytosis. Administration of hhep25 concomitant with or 4 hours after a single intravenous dose of hemoglobin abolished hemoglobin-induced upregulation of urinary kidney injury markers (NGAL and KIM-1) and renal Interleukin-6 and Ngal mRNA observed 24 hours after administration but did not affect renal ferroportin expression at this point. Notably, coadministration of hhep25 and hemoglobin but not administration of either alone greatly increased renal mRNA expression of hepcidin-encoding Hamp1 and hepcidin staining in distal tubules. These findings suggest a role for locally synthesized hepcidin in renal protection. Our observations did not support a role for ferroportin in hhep25-mediated protection against hemoglobin-induced early injury, but other mechanisms of cellular iron handling may be involved. In conclusion, our data suggest that both systemically delivered and locally produced hepcidin protect against hemoglobin-induced AKI.
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Affiliation(s)
| | | | | | | | | | | | - Frank Thévenod
- Institute of Physiology, Pathophysiology and Toxicology, Center for Biomedical Training and Research, University of Witten/Herdecke, Witten, Germany; and
| | - Rosalinde Masereeuw
- Pharmacology and Toxicology, Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht, The Netherlands
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Mehta K, Greenwell P, Renshaw D, Busbridge M, Garcia M, Farnaud S, Patel VB. Characterisation of hepcidin response to holotransferrin treatment in CHO TRVb-1 cells. Blood Cells Mol Dis 2015; 55:110-8. [PMID: 26142326 DOI: 10.1016/j.bcmd.2015.05.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/06/2015] [Accepted: 05/06/2015] [Indexed: 01/20/2023]
Abstract
Iron overload coupled with low hepcidin levels are characteristics of hereditary haemochromatosis. To understand the role of transferrin receptor (TFR) and intracellular iron in hepcidin secretion, Chinese hamster ovary transferrin receptor variant (CHO TRVb-1) cells were used that express iron-response-element-depleted human TFRC mRNA (TFRC∆IRE). Results showed that CHO TRVb-1 cells expressed higher basal levels of cell-surface TFR1 than HepG2 cells (2.2-fold; p < 0.01) and following 5 g/L holotransferrin treatment maintained constitutive over-expression at 24h and 48 h, contrasting the HepG2 cells where the receptor levels significantly declined. Despite this, the intracellular iron content was neither higher than HepG2 cells nor increased over time under basal or holotransferrin-treated conditions. Interestingly, hepcidin secretion in CHO TRVb-1 cells exceeded basal levels at all time-points (p < 0.02) and matched levels in HepG2 cells following treatment. While TFRC mRNA expression showed expected elevation (2h, p < 0.03; 4h; p < 0.05), slc40a1 mRNA expression was also elevated (2 h, p < 0.05; 4 h, p < 0.03), unlike the HepG2 cells. In conclusion, the CHO TRVb-1 cells prevented cellular iron-overload by elevating slc40a1 expression, thereby highlighting its significance in the absence of iron-regulated TFRC mRNA. Furthermore, hepcidin response to holotransferrin treatment was similar to HepG2 cells and resembled the human physiological response.
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Affiliation(s)
- Kosha Mehta
- Department of Biomedical Sciences, University of Westminster, London W1W 6UW, UK
| | - Pamela Greenwell
- Department of Biomedical Sciences, University of Westminster, London W1W 6UW, UK
| | - Derek Renshaw
- Faculty of Health & Life Sciences, Coventry University, Coventry, CV1 5FB, UK
| | - Mark Busbridge
- Department of Clinical Biochemistry, Charing Cross Hospital, Imperial College Healthcare NHS Trust, London W6 8RF, UK
| | - Mitla Garcia
- Randall Division of Cell and Molecular Biophysics, King's College London SE1 1UL, UK
| | - Sebastien Farnaud
- Department of Life Sciences, University of Bedfordshire, Luton, LU1 3JU, UK
| | - Vinood B Patel
- Department of Biomedical Sciences, University of Westminster, London W1W 6UW, UK.
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Liu F, Geng J, Gumpper RH, Barman A, Davis I, Ozarowski A, Hamelberg D, Liu A. An Iron Reservoir to the Catalytic Metal: THE RUBREDOXIN IRON IN AN EXTRADIOL DIOXYGENASE. J Biol Chem 2015; 290:15621-15634. [PMID: 25918158 DOI: 10.1074/jbc.m115.650259] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2015] [Indexed: 01/06/2023] Open
Abstract
The rubredoxin motif is present in over 74,000 protein sequences and 2,000 structures, but few have known functions. A secondary, non-catalytic, rubredoxin-like iron site is conserved in 3-hydroxyanthranilate 3,4-dioxygenase (HAO), from single cellular sources but not multicellular sources. Through the population of the two metal binding sites with various metals in bacterial HAO, the structural and functional relationship of the rubredoxin-like site was investigated using kinetic, spectroscopic, crystallographic, and computational approaches. It is shown that the first metal presented preferentially binds to the catalytic site rather than the rubredoxin-like site, which selectively binds iron when the catalytic site is occupied. Furthermore, an iron ion bound to the rubredoxin-like site is readily delivered to an empty catalytic site of metal-free HAO via an intermolecular transfer mechanism. Through the use of metal analysis and catalytic activity measurements, we show that a downstream metabolic intermediate can selectively remove the catalytic iron. As the prokaryotic HAO is often crucial for cell survival, there is a need for ensuring its activity. These results suggest that the rubredoxin-like site is a possible auxiliary iron source to the catalytic center when it is lost during catalysis in a pathway with metabolic intermediates of metal-chelating properties. A spare tire concept is proposed based on this biochemical study, and this concept opens up a potentially new functional paradigm for iron-sulfur centers in iron-dependent enzymes as transient iron binding and shuttling sites to ensure full metal loading of the catalytic site.
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Affiliation(s)
- Fange Liu
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303.
| | - Jiafeng Geng
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303; Molecular Basis of Disease Program, Georgia State University, Atlanta, Georgia 30303.
| | - Ryan H Gumpper
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303
| | - Arghya Barman
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303
| | - Ian Davis
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303; Molecular Basis of Disease Program, Georgia State University, Atlanta, Georgia 30303
| | - Andrew Ozarowski
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310
| | - Donald Hamelberg
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303; Molecular Basis of Disease Program, Georgia State University, Atlanta, Georgia 30303
| | - Aimin Liu
- Department of Chemistry, Georgia State University, Atlanta, Georgia 30303; Center for Diagnostics and Therapeutics, Georgia State University, Atlanta, Georgia 30303; Molecular Basis of Disease Program, Georgia State University, Atlanta, Georgia 30303.
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Peters HPE, Laarakkers CMM, Pickkers P, Masereeuw R, Boerman OC, Eek A, Cornelissen EAM, Swinkels DW, Wetzels JFM. Tubular reabsorption and local production of urine hepcidin-25. BMC Nephrol 2013; 14:70. [PMID: 23531037 PMCID: PMC3623618 DOI: 10.1186/1471-2369-14-70] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Accepted: 02/19/2013] [Indexed: 12/21/2022] Open
Abstract
Background Hepcidin is a central regulator of iron metabolism. Serum hepcidin levels are increased in patients with renal insufficiency, which may contribute to anemia. Urine hepcidin was found to be increased in some patients after cardiac surgery, and these patients were less likely to develop acute kidney injury. It has been suggested that urine hepcidin may protect by attenuating heme-mediated injury, but processes involved in urine hepcidin excretion are unknown. Methods To assess the role of tubular reabsorption we compared fractional excretion (FE) of hepcidin-25 with FE of β2-microglobulin (β2m) in 30 patients with various degrees of tubular impairment due to chronic renal disease. To prove that hepcidin is reabsorbed by the tubules in a megalin-dependent manner, we measured urine hepcidin-1 in wild-type and kidney specific megalin-deficient mice. Lastly, we evaluated FE of hepcidin-25 and β2m in 19 patients who underwent cardiopulmonary bypass surgery. Hepcidin was measured by a mass spectrometry assay (MS), whereas β2m was measured by ELISA. Results In patients with chronic renal disease, FE of hepcidin-25 was strongly correlated with FE of β2m (r = 0.93, P <0.01). In megalin-deficient mice, urine hepcidin-1 was 7-fold increased compared to wild-type mice (p < 0.01) indicating that proximal tubular reabsorption occurs in a megalin- dependent manner. Following cardiac surgery, FE of hepcidin-25 increased despite a decline in FE of β2m, potentially indicating local production at 12–24 hours. Conclusions Hepcidin-25 is reabsorbed by the renal tubules and increased urine hepcidin-25 levels may reflect a reduction in tubular uptake. Uncoupling of FE of hepcidin-25 and β2m in cardiac surgery patients suggests local production.
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Affiliation(s)
- Hilde P E Peters
- Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
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Kroot JJC, Tjalsma H, Fleming RE, Swinkels DW. Hepcidin in human iron disorders: diagnostic implications. Clin Chem 2011; 57:1650-69. [PMID: 21989113 DOI: 10.1373/clinchem.2009.140053] [Citation(s) in RCA: 180] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
BACKGROUND The peptide hormone hepcidin plays a central role in regulating dietary iron absorption and body iron distribution. Many human diseases are associated with alterations in hepcidin concentrations. The measurement of hepcidin in biological fluids is therefore a promising tool in the diagnosis and management of medical conditions in which iron metabolism is affected. CONTENT We describe hepcidin structure, kinetics, function, and regulation. We moreover explore the therapeutic potential for modulating hepcidin expression and the diagnostic potential for hepcidin measurements in clinical practice. SUMMARY Cell-culture, animal, and human studies have shown that hepcidin is predominantly synthesized by hepatocytes, where its expression is regulated by body iron status, erythropoietic activity, oxygen tension, and inflammatory cytokines. Hepcidin lowers serum iron concentrations by counteracting the function of ferroportin, a major cellular iron exporter present in the membrane of macrophages, hepatocytes, and the basolateral site of enterocytes. Hepcidin is detected in biologic fluids as a 25 amino acid isoform, hepcidin-25, and 2 smaller forms, i.e., hepcidin-22 and -20; however, only hepcidin-25 has been shown to participate in the regulation of iron metabolism. Reliable assays to measure hepcidin in blood and urine by use of immunochemical and mass spectrometry methods have been developed. Results of proof-of-principle studies have highlighted hepcidin as a promising diagnostic tool and therapeutic target for iron disorders. However, before hepcidin measurements can be used in routine clinical practice, efforts will be required to assess the relevance of hepcidin isoform measurements, to harmonize the different assays, to define clinical decision limits, and to increase assay availability for clinical laboratories.
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Affiliation(s)
- Joyce J C Kroot
- Department of Laboratory Medicine, Laboratory of Genetic, Endocrine and Metabolic Disorders, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
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Desbenoît N, Galardon E, Frapart Y, Tomas A, Artaud I. Reductive metalation of cyclic and acyclic pseudopeptidic bis-disulfides and back conversion of the resulting diamidato/dithiolato complexes to bis-disulfides. Inorg Chem 2011; 49:8637-44. [PMID: 20718487 DOI: 10.1021/ic101148c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cyclic and acyclic pseudopeptidic bis-disulfides built on an o-phenylene diamine scaffold were prepared: (N(2)H(2)S(2))(2), 1a, N(2)H(2)(S-SCH(3))(2), 1b, and N(2)H(2)(S-StBu)(2), 1c. Reductive metalation of these disulfides with (PF(6))[Cu(CH(3)CN)(4)] in the presence of Et(4)NOH as a base, or with (Et(4)N)[Fe(SEt)(4)] and Et(4)NCl, yields the corresponding diamidato/dithiolato copper(III) or iron(III) complex, (Et(4)N)[Cu(N(2)S(2))], 2, or (Et(4)N)(2)[Fe(N(2)S(2))Cl], 5. These complexes display characteristics similar to those previously described in the literature. The mechanism of the metalation with copper has been investigated by X-band electron paramagnetic resonance (EPR) spectroscopy at 10 K. After metalation of the bis-disulfide 1c and deprotonation of the amide nitrogens, the reductive cleavage of the S-S bonds occurs by two one-electron transfers leading to the intermediate formation of a copper(II) complex and a thyil radical. Complexes 2 and 5 can be converted back to the cyclic bis-disulfide 1a with iodine in an 80% yield. Reaction of 5 with iodine in the presence of CH(3)S-SCH(3) affords a 1/1 mixture of the acyclic N(2)H(2)(S-SCH(3))(2) disulfide 1b and cyclic bis-disulfide 1a. From 2, the reaction was monitored by (1)H NMR and gives 1b as major product. While there is no reaction of 2 or 5 with tBuS-StBu and iodine, reaction with an excess of tBuSI affords quantitatively the di-tert-butyl disulfide 1c. To assess the role of the Cu(III) oxidation state, control experiments were carried out under strictly anaerobic conditions with the copper(II) complex, (Et(4)N)(2)[Cu(N(2)S(2))], 6. Complex 6 is oxidized to 2 by iodine, and it reacts with an excess of tBuSI, yielding 1c as final product, through the intermediate formation of complex 2.
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Affiliation(s)
- Nicolas Desbenoît
- Laboratoire de Chimie et Biochimie Pharmacologiques et Toxicologiques, Université Paris Descartes, UMR 8601, CNRS, 45 rue des Saints Pères, 75270 Paris Cedex 06, France
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Desbenoit N, Galardon E, Deschamps P, Roussel P, Vaulont S, Artaud I, Tomas A. Métallation réversible d’un analogue bis-disulfure du site de liaison Cys*-X-Cys* de l’hepcidine : caractérisation structurale du complexe de cuivre associé. ANNALES PHARMACEUTIQUES FRANÇAISES 2010; 68:388-96. [DOI: 10.1016/j.pharma.2010.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2010] [Revised: 06/23/2010] [Accepted: 08/03/2010] [Indexed: 11/28/2022]
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Tselepis C, Ford S, McKie A, Vogel W, Zoller H, Simpson R, Diaz Castro J, Iqbal T, Ward D. Characterization of the transition-metal-binding properties of hepcidin. Biochem J 2010; 427:289-296. [DOI: 10.1042/bj20091521] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/30/2023]
Abstract
Accumulating evidence suggests that hepcidin, a 25-residue peptide hormone, is the master regulator of iron metabolism. Further evidence suggests that the five N-terminal amino acids are crucial for mediating its biological function. With a histidine residue at position 3, this region also has the potential to bind bivalent metal ions. To characterize this hepcidin–metal interaction in detail, the present study utilizes electrospray MS to measure the binding of a range of metal ions to wild-type and mutant human and murine hepcidins. In addition, the biological effects of these point mutations were tested on Caco-2 and HEK-293T human cell lines and in mice. Our results show that hepcidin-25 can form complexes with copper, nickel and zinc; however, we failed to detect any hepcidin-25 binding to either ferric or ferrous ions. The greatest affinity observed was between hepcidin-25 and copper with a dissociation constant ≪1 μM. Substituting the histidine residue at position 3 in human hepcidin-25 and comparably the asparagine residue at position 3 in murine hepcidin-25 with an alanine residue markedly diminished the affinity for copper. The amino acid substitutions also decreased the biological activity of hepcidin-25; namely repression of ferroportin protein levels and hypoferraemia. In summary, the high affinity of hepcidin for copper suggests that hepcidin could bind copper in vivo and this may be of biological relevance.
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Affiliation(s)
- Chris Tselepis
- School of Cancer Sciences, University of Birmingham, Vincent Drive, Birmingham B15 2TT, U.K
| | - Samuel J. Ford
- School of Cancer Sciences, University of Birmingham, Vincent Drive, Birmingham B15 2TT, U.K
| | - Andrew T. McKie
- Division of Nutritional Sciences, King's College London, 150 Stamford Street, London SE1 9NH, U.K
| | - Wolfgang Vogel
- Medical University of Innsbruck, Department of Medicine II, Gastroenterology and Hepatology, Innsbruck, Austria
| | - Heinz Zoller
- Medical University of Innsbruck, Department of Medicine II, Gastroenterology and Hepatology, Innsbruck, Austria
| | - Robert J. Simpson
- Division of Nutritional Sciences, King's College London, 150 Stamford Street, London SE1 9NH, U.K
| | - Javier Diaz Castro
- School of Cancer Sciences, University of Birmingham, Vincent Drive, Birmingham B15 2TT, U.K
| | - Tariq H. Iqbal
- School of Cancer Sciences, University of Birmingham, Vincent Drive, Birmingham B15 2TT, U.K
| | - Douglas G. Ward
- School of Cancer Sciences, University of Birmingham, Vincent Drive, Birmingham B15 2TT, U.K
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Silva FD, Rezende CA, Rossi DCP, Esteves E, Dyszy FH, Schreier S, Gueiros-Filho F, Campos CB, Pires JR, Daffre S. Structure and mode of action of microplusin, a copper II-chelating antimicrobial peptide from the cattle tick Rhipicephalus (Boophilus) microplus. J Biol Chem 2009; 284:34735-46. [PMID: 19828445 DOI: 10.1074/jbc.m109.016410] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Microplusin, a Rhipicephalus (Boophilus) microplus antimicrobial peptide (AMP) is the first fully characterized member of a new family of cysteine-rich AMPs with histidine-rich regions at the N and C termini. In the tick, microplusin belongs to the arsenal of innate defense molecules active against bacteria and fungi. Here we describe the NMR solution structure of microplusin and demonstrate that the protein binds copper II and iron II. Structured as a single alpha-helical globular domain, microplusin consists of five alpha-helices: alpha1 (residues Gly-9 to Arg-21), alpha2 (residues Glu-27 to Asn-40), alpha3 (residues Arg-44 to Thr-54), alpha4 (residues Leu-57 to Tyr-64), and alpha5 (residues Asn-67 to Cys-80). The N and C termini are disordered. This structure is unlike any other AMP structures described to date. We also used NMR spectroscopy to map the copper binding region on microplusin. Finally, using the Gram-positive bacteria Micrococcus luteus as a model, we studied of mode of action of microplusin. Microplusin has a bacteriostatic effect and does not permeabilize the bacterial membrane. Because microplusin binds metals, we tested whether this was related to its antimicrobial activity. We found that the bacteriostatic effect of microplusin was fully reversed by supplementation of culture media with copper II but not iron II. We also demonstrated that microplusin affects M. luteus respiration, a copper-dependent process. Thus, we conclude that the antibacterial effect of microplusin is due to its ability to bind and sequester copper II.
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Affiliation(s)
- Fernanda D Silva
- Departamento de Parasitologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, 05508-900 São Paulo, Brazil
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Kell DB. Iron behaving badly: inappropriate iron chelation as a major contributor to the aetiology of vascular and other progressive inflammatory and degenerative diseases. BMC Med Genomics 2009; 2:2. [PMID: 19133145 PMCID: PMC2672098 DOI: 10.1186/1755-8794-2-2] [Citation(s) in RCA: 369] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2008] [Accepted: 01/08/2009] [Indexed: 01/19/2023] Open
Abstract
BACKGROUND The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular 'reactive oxygen species' (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. REVIEW We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation).The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible.This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, since in some circumstances (especially the presence of poorly liganded iron) molecules that are nominally antioxidants can actually act as pro-oxidants. The reduction of redox stress thus requires suitable levels of both antioxidants and effective iron chelators. Some polyphenolic antioxidants may serve both roles.Understanding the exact speciation and liganding of iron in all its states is thus crucial to separating its various pro- and anti-inflammatory activities. Redox stress, innate immunity and pro- (and some anti-)inflammatory cytokines are linked in particular via signalling pathways involving NF-kappaB and p38, with the oxidative roles of iron here seemingly involved upstream of the IkappaB kinase (IKK) reaction. In a number of cases it is possible to identify mechanisms by which ROSs and poorly liganded iron act synergistically and autocatalytically, leading to 'runaway' reactions that are hard to control unless one tackles multiple sites of action simultaneously. Some molecules such as statins and erythropoietin, not traditionally associated with anti-inflammatory activity, do indeed have 'pleiotropic' anti-inflammatory effects that may be of benefit here. CONCLUSION Overall we argue, by synthesising a widely dispersed literature, that the role of poorly liganded iron has been rather underappreciated in the past, and that in combination with peroxide and superoxide its activity underpins the behaviour of a great many physiological processes that degrade over time. Understanding these requires an integrative, systems-level approach that may lead to novel therapeutic targets.
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Affiliation(s)
- Douglas B Kell
- School of Chemistry and Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess St, Manchester, M1 7DN, UK.
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