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Formica V, Riondino S, Morelli C, Guerriero S, D'Amore F, Di Grazia A, Del Vecchio Blanco G, Sica G, Arkenau HT, Monteleone G, Roselli M. HIF2α, Hepcidin and their crosstalk as tumour-promoting signalling. Br J Cancer 2023; 129:222-236. [PMID: 37081189 PMCID: PMC10338631 DOI: 10.1038/s41416-023-02266-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 03/25/2023] [Accepted: 03/30/2023] [Indexed: 04/22/2023] Open
Abstract
Not all aspects of the disruption of iron homeostasis in cancer have been fully elucidated. Iron accumulation in cancer cells is frequent for many solid tumours, and this is often accompanied by the contemporary rise of two key iron regulators, HIF2α and Hepcidin. This scenario is different from what happens under physiological conditions, where Hepcidin parallels systemic iron concentrations while HIF2α levels are inversely associated to Hepcidin. The present review highlights the increasing body of evidence for the pro-tumoral effect of HIF2α and Hepcidin, discusses the possible imbalance in HIF2α, Hepcidin and iron homeostasis during cancer, and explores therapeutic options relying on these pathways as anticancer strategies.
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Affiliation(s)
- Vincenzo Formica
- Medical Oncology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Viale Oxford, 81, 00133, Rome, Italy.
| | - Silvia Riondino
- Medical Oncology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Viale Oxford, 81, 00133, Rome, Italy
| | - Cristina Morelli
- Medical Oncology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Viale Oxford, 81, 00133, Rome, Italy
- PhD Program in Systems and Experimental Medicine (XXXV cycle), University of Rome Tor Vergata, Via Montpellier 1, 00133, Rome, Italy
| | - Simona Guerriero
- Medical Oncology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Viale Oxford, 81, 00133, Rome, Italy
| | - Federica D'Amore
- Medical Oncology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Viale Oxford, 81, 00133, Rome, Italy
| | - Antonio Di Grazia
- Gastroenterology Unit, Department of Systems Medicine, University of Rome Tor Vergata, 00133, Rome, Italy
| | | | - Giuseppe Sica
- Department of Surgery, University of Rome Tor Vergata, Rome, Italy
| | | | - Giovanni Monteleone
- Gastroenterology Unit, Department of Systems Medicine, University of Rome Tor Vergata, 00133, Rome, Italy
| | - Mario Roselli
- Medical Oncology Unit, Department of Systems Medicine, University of Rome Tor Vergata, Viale Oxford, 81, 00133, Rome, Italy
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2
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Di Modica SM, Tanzi E, Olivari V, Lidonnici MR, Pettinato M, Pagani A, Tiboni F, Furiosi V, Silvestri L, Ferrari G, Rivella S, Nai A. Transferrin receptor 2 (Tfr2) genetic deletion makes transfusion-independent a murine model of transfusion-dependent β-thalassemia. Am J Hematol 2022; 97:1324-1336. [PMID: 36071579 PMCID: PMC9540808 DOI: 10.1002/ajh.26673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Revised: 07/25/2022] [Accepted: 07/27/2022] [Indexed: 01/24/2023]
Abstract
β-thalassemia is a genetic disorder caused by mutations in the β-globin gene, and characterized by anemia, ineffective erythropoiesis and iron overload. Patients affected by the most severe transfusion-dependent form of the disease (TDT) require lifelong blood transfusions and iron chelation therapy, a symptomatic treatment associated with several complications. Other therapeutic opportunities are available, but none is fully effective and/or applicable to all patients, calling for the identification of novel strategies. Transferrin receptor 2 (TFR2) balances red blood cells production according to iron availability, being an activator of the iron-regulatory hormone hepcidin in the liver and a modulator of erythropoietin signaling in erythroid cells. Selective Tfr2 deletion in the BM improves anemia and iron-overload in non-TDT mice, both as a monotherapy and, even more strikingly, in combination with iron-restricting approaches. However, whether Tfr2 targeting might represent a therapeutic option for TDT has never been investigated so far. Here, we prove that BM Tfr2 deletion improves anemia, erythrocytes morphology and ineffective erythropoiesis in the Hbbth1/th2 murine model of TDT. This effect is associated with a decrease in the expression of α-globin, which partially corrects the unbalance with β-globin chains and limits the precipitation of misfolded hemoglobin, and with a decrease in the activation of unfolded protein response. Remarkably, BM Tfr2 deletion is also sufficient to avoid long-term blood transfusions required for survival of Hbbth1/th2 animals, preventing mortality due to chronic anemia and reducing transfusion-associated complications, such as progressive iron-loading. Altogether, TFR2 targeting might represent a promising therapeutic option also for TDT.
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Affiliation(s)
- Simona Maria Di Modica
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell BiologyOspedale San RaffaeleMilanItaly
| | - Emanuele Tanzi
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell BiologyOspedale San RaffaeleMilanItaly
| | - Violante Olivari
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell BiologyOspedale San RaffaeleMilanItaly,Vita Salute San Raffaele UniversityMilanItaly
| | - Maria Rosa Lidonnici
- San Raffaele Telethon Institute for Gene Therapy (SR‐TIGET)Ospedale San RaffaeleMilanItaly
| | - Mariateresa Pettinato
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell BiologyOspedale San RaffaeleMilanItaly,Vita Salute San Raffaele UniversityMilanItaly
| | - Alessia Pagani
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell BiologyOspedale San RaffaeleMilanItaly
| | - Francesca Tiboni
- San Raffaele Telethon Institute for Gene Therapy (SR‐TIGET)Ospedale San RaffaeleMilanItaly
| | - Valeria Furiosi
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell BiologyOspedale San RaffaeleMilanItaly
| | - Laura Silvestri
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell BiologyOspedale San RaffaeleMilanItaly,Vita Salute San Raffaele UniversityMilanItaly
| | - Giuliana Ferrari
- Vita Salute San Raffaele UniversityMilanItaly,San Raffaele Telethon Institute for Gene Therapy (SR‐TIGET)Ospedale San RaffaeleMilanItaly
| | - Stefano Rivella
- Division of Hematology, Department of PediatricsChildren's Hospital of PhiladelphiaPhiladelphiaPennsylvaniaUSA
| | - Antonella Nai
- Regulation of Iron Metabolism Unit, Division of Genetics and Cell BiologyOspedale San RaffaeleMilanItaly,Vita Salute San Raffaele UniversityMilanItaly
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3
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Hepcidin in hepatocellular carcinoma. Br J Cancer 2022; 127:185-192. [PMID: 35264787 PMCID: PMC9296449 DOI: 10.1038/s41416-022-01753-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 01/26/2022] [Accepted: 02/09/2022] [Indexed: 02/06/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is one of the most common reasons for cancer-related deaths. Excess iron increases HCC risk. Inevitably, hepcidin, the iron hormone that maintains systemic iron homoeostasis is involved in HCC pathology. Distinct from other cancers that show high hepcidin expression, HCC patients can show low hepcidin levels. Thus, it is of immense clinical benefit to address the regulation and action of hepcidin in HCC as this may help in identifying molecular targets for diagnosis, prognosis, and therapeutics. Accordingly, this review explores hepcidin in HCC. It presents the levels of tissue and serum hepcidin and explains the mechanisms that contribute to hepcidin reduction in HCC. These include downregulation of HAMP, TfR2, HJV, ALK2 and circular RNA circ_0004913, upregulation of matriptase-2 and GDF15, inactivation of RUNX3 and mutation in TP53. The enigmas around mir-122 and the functionalities of two major hepcidin inducers BMP6 and IL6 in relation to hepcidin in HCC are discussed. Effects of hepcidin downregulation are explained, specifically, increased cancer proliferation via activation of CDK1/STAT3 pathway and increased HCC risk due to reduction in a hepcidin-mediated protective effect against hepatic stellate cell activation. Hepcidin–ferroportin axis in HCC is addressed. Finally, the role of hepcidin in the diagnosis, prognosis and therapeutics of HCC is highlighted.
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Orphan Nuclear Receptor ERRγ Is a Transcriptional Regulator of CB1 Receptor-Mediated TFR2 Gene Expression in Hepatocytes. Int J Mol Sci 2021; 22:ijms22116021. [PMID: 34199599 PMCID: PMC8199698 DOI: 10.3390/ijms22116021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 05/20/2021] [Accepted: 05/27/2021] [Indexed: 11/23/2022] Open
Abstract
Orphan nuclear receptor estrogen-related receptor γ (ERRγ) is an important transcription factor modulating gene transcription involved in endocrine control of liver metabolism. Transferrin receptor 2 (TFR2), a carrier protein for transferrin, is involved in hepatic iron overload in alcoholic liver disease (ALD). However, TFR2 gene transcriptional regulation in hepatocytes remains largely unknown. In this study, we described a detailed molecular mechanism of hepatic TFR2 gene expression involving ERRγ in response to an endocannabinoid 2-arachidonoylglycerol (2-AG). Treatment with 2-AG and arachidonyl-2′-chloroethylamide, a selective cannabinoid receptor type 1 (CB1) receptor agonist, increased ERRγ and TFR2 expression in hepatocytes. Overexpression of ERRγ was sufficient to induce TFR2 expression in both human and mouse hepatocytes. In addition, ERRγ knockdown significantly decreased 2-AG or alcohol-mediated TFR2 gene expression in cultured hepatocytes and mouse livers. Finally, deletion and mutation analysis of the TFR2 gene promoter demonstrated that ERRγ directly modulated TFR2 gene transcription via binding to an ERR-response element. This was further confirmed by chromatin immunoprecipitation assay. Taken together, these results reveal a previously unrecognized role of ERRγ in the transcriptional regulation of TFR2 gene expression in response to alcohol.
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Iron elevates mesenchymal and metastatic biomarkers in HepG2 cells. Sci Rep 2020; 10:21926. [PMID: 33318518 PMCID: PMC7736862 DOI: 10.1038/s41598-020-78348-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 11/23/2020] [Indexed: 01/20/2023] Open
Abstract
Liver iron excess is observed in several chronic liver diseases and is associated with the development of hepatocellular carcinoma (HCC). However, apart from oxidative stress, other cellular mechanisms by which excess iron may mediate/increase HCC predisposition/progression are not known. HCC pathology involves epithelial to mesenchymal transition (EMT), the basis of cancer phenotype acquisition. Here, the effect of excess iron (holo-transferrin 0–2 g/L for 24 and 48 h) on EMT biomarkers in the liver-derived HepG2 cells was investigated. Holo-transferrin substantially increased intracellular iron. Unexpectedly, mRNA and protein expression of the epithelial marker E-cadherin either remained unaltered or increased. The mRNA and protein levels of metastasis marker N-cadherin and mesenchymal marker vimentin increased significantly. While the mRNA expression of EMT transcription factors SNAI1 and SNAI2 increased and decreased, respectively after 24 h, both factors increased after 48 h. The mRNA expression of TGF-β (EMT-inducer) showed no significant alterations. In conclusion, data showed direct link between iron and EMT. Iron elevated mesenchymal and metastatic biomarkers in HepG2 cells without concomitant decrement in the epithelial marker E-cadherin and altered the expression of the key EMT-mediating transcription factors. Such studies can help identify molecular targets to devise iron-related adjunctive therapies to ameliorate HCC pathophysiology.
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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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7
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Sharp PA, Clarkson R, Hussain A, Weeks RJ, Morison IM. DNA methylation of hepatic iron sensing genes and the regulation of hepcidin expression. PLoS One 2018; 13:e0197863. [PMID: 29771984 PMCID: PMC5957407 DOI: 10.1371/journal.pone.0197863] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/09/2018] [Indexed: 12/15/2022] Open
Abstract
Production of the iron regulatory peptide hepcidin is tightly controlled by a network of proteins in hepatocytes that sense levels of iron in the circulation (as diferric-transferrin) and in tissues (in ferritin). Human studies show high variability in the normal range of serum hepcidin levels. We have postulated that this may, in part, be related to inter-individual variability in the expression of genes in the iron sensing pathway, potentially governed by epigenetic factors. Here, we have investigated whether genes encoding hepatic iron sensing proteins and hepcidin are regulated by DNA methylation. Experiments were performed on two human hepatoma cell lines, HepG2 cells and Huh7 cells. Basal expression of TFR2 and HAMP was significantly lower in Huh7 cells compared with HepG2 cells. Analysis of bisulphite-converted DNA from Huh7 cells revealed partial methylation of TFR2 (alpha transcript), which could result in gene silencing. Demethylation using 5-aza-2’-deoxycitidine (AZA) increased TFR2 mRNA expression in Huh7. PCR analysis of bisulphite-converted HAMP promoter DNA, using methylation-specific primers, revealed no differences between cell lines. However, HAMP mRNA expression in Huh7 was increased by AZA treatment, suggesting that methylation of one or more iron sensing genes may indirectly influence HAMP expression. Our study provides evidence that DNA methylation might control expression of HAMP and other hepatic iron sensing genes, and indicates that epigenetic influences on iron homeostasis warrant further investigation.
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Affiliation(s)
- Paul A. Sharp
- Department of Nutritional Sciences, School of Life Course Sciences, King’s College London, London, United Kingdom
- * E-mail:
| | - Rachel Clarkson
- Department of Nutritional Sciences, School of Life Course Sciences, King’s College London, London, United Kingdom
| | - Ahmed Hussain
- Department of Nutritional Sciences, School of Life Course Sciences, King’s College London, London, United Kingdom
| | - Robert J. Weeks
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
| | - Ian M. Morison
- Department of Pathology, Dunedin School of Medicine, University of Otago, Dunedin, New Zealand
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Mehta KJ, Farnaud S, Patel VB. HFE mRNA expression is responsive to intracellular and extracellular iron loading: short communication. Mol Biol Rep 2017; 44:399-403. [PMID: 28840425 PMCID: PMC5640751 DOI: 10.1007/s11033-017-4123-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 08/19/2017] [Indexed: 11/28/2022]
Abstract
In liver hepatocytes, the HFE gene regulates cellular and systemic iron homeostasis by modulating cellular iron-uptake and producing the iron-hormone hepcidin in response to systemic iron elevation. However, the mechanism of iron-sensing in hepatocytes remain enigmatic. Therefore, to study the effect of iron on HFE and hepcidin (HAMP) expressions under distinct extracellular and intracellular iron-loading, we examined the effect of holotransferrin treatment (1, 2, 5 and 8 g/L for 6 h) on intracellular iron levels, and mRNA expressions of HFE and HAMP in wild-type HepG2 and previously characterized iron-loaded recombinant-TfR1 HepG2 cells. Gene expression was analyzed by real-time PCR and intracellular iron was measured by ferrozine assay. Data showed that in the wild-type cells, where intracellular iron content remained unchanged, HFE expression remained unaltered at low holotransferrin treatments but was upregulated upon 5 g/L (p < 0.04) and 8 g/L (p = 0.05) treatments. HAMP expression showed alternating elevations and increased upon 1 g/L (p < 0.05) and 5 g/L (p < 0.05). However, in the recombinant cells that showed higher intracellular iron levels than wild-type cells, HFE and HAMP expressions were elevated only at low 1 g/L treatment (p < 0.03) and were repressed at 2 g/L treatment (p < 0.03). Under holotransferrin-untreated conditions, the iron-loaded recombinant cells showed higher expressions of HFE (p < 0.03) and HAMP (p = 0.05) than wild-type cells. HFE mRNA was independently elevated by extracellular and intracellular iron-excess. Thus, it may be involved in sensing both, extracellular and intracellular iron. Repression of HAMP expression under simultaneous intracellular and extracellular iron-loading resembles non-hereditary iron-excess pathologies.
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Affiliation(s)
- Kosha J Mehta
- Department of Biomedical Sciences, University of Westminster, 115 New Cavendish Street, London, W1W 6UW, UK
| | - Sebastien Farnaud
- School of Life Sciences, Coventry University, 138 James Starley Building, Coventry, CV1 5FB, UK
| | - Vinood B Patel
- Department of Biomedical Sciences, University of Westminster, 115 New Cavendish Street, London, W1W 6UW, UK.
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Metzendorf C, Zeigerer A, Seifert S, Sparla R, Najafi B, Canonne-Hergaux F, Zerial M, Muckenthaler MU. Acute loss of the hepatic endo-lysosomal system in vivo causes compensatory changes in iron homeostasis. Sci Rep 2017. [PMID: 28642463 PMCID: PMC5481338 DOI: 10.1038/s41598-017-02898-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Liver cells communicate with the extracellular environment to take up nutrients via endocytosis. Iron uptake is essential for metabolic activities and cell homeostasis. Here, we investigated the role of the endocytic system for maintaining iron homeostasis. We specifically depleted the small GTPase Rab5 in the mouse liver, causing a transient loss of the entire endo-lysosomal system. Strikingly, endosome depletion led to a fast reduction of hepatic iron levels, which was preceded by an increased abundance of the iron exporter ferroportin. Compensatory changes in livers of Rab5-depleted mice include increased expression of transferrin receptor 1 as well as reduced expression of the iron-regulatory hormone hepcidin. Serum iron indices (serum iron, free iron binding capacity and total iron binding capacity) in Rab5-KD mice were increased, consistent with an elevated splenic and hepatic iron export. Our data emphasize the critical importance of the endosomal compartments in hepatocytes to maintain hepatic and systemic iron homeostasis in vivo. The short time period (between day four and five) upon which these changes occur underscore the fast dynamics of the liver iron pool.
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Affiliation(s)
- Christoph Metzendorf
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany.,Molecular Medicine Partnership Unit, 69120, Heidelberg, Germany.,Heidelberg University Biochemistry Center (BZH), INF 327, 69120, Heidelberg, Germany
| | - Anja Zeigerer
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany.,Institute for Diabetes and Cancer, Helmholtz Center for Environmental Health, 85764, Neuherberg, Germany
| | - Sarah Seifert
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | - Richard Sparla
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany.,Molecular Medicine Partnership Unit, 69120, Heidelberg, Germany
| | - Bahar Najafi
- German Center for Diabetes Research (DZD), 85764, Neuherberg, Germany.,Institute for Diabetes and Cancer, Helmholtz Center for Environmental Health, 85764, Neuherberg, Germany
| | | | - Marino Zerial
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307, Dresden, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Hematology, Oncology and Immunology University of Heidelberg, Heidelberg University Clinic, INF 350, 69120, Heidelberg, Germany. .,Molecular Medicine Partnership Unit, 69120, Heidelberg, 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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11
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Duodenal ferroportin is up-regulated in patients with chronic hepatitis C. PLoS One 2014; 9:e110658. [PMID: 25330009 PMCID: PMC4203811 DOI: 10.1371/journal.pone.0110658] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2014] [Accepted: 09/18/2014] [Indexed: 12/13/2022] Open
Abstract
Hepatitis C virus (HCV) infection is a leading cause of liver-related mortality. Chronic hepatitis C (CHC) is frequently associated with disturbances in iron homeostasis, with serum iron and hepatic iron stores being elevated. Accumulating evidence indicates that chronic HCV infection suppresses expression of hepatic hepcidin, a key mediator of iron homeostasis, leading to iron overload conditions. Since hepcidin mediates degradation of ferroportin, a basolateral transporter involved in the release of iron from cells, diminished hepcidin expression probably leads to up-regulation of ferroportin-1 (Fpn1) in patients with CHC. In this study, we determined the protein levels of duodenal Fpn1, and found that its expression was significantly up-regulated in patients with CHC. The expression of duodenal Fpn1 is negatively correlated with mRNA levels of hepcidin, and positively correlated with serum iron parameters. Although iron is a critical factor for growth of a variety of pathogenic bacteria, our results suggest that iron overload in blood does not increase the infection rate of bacteria in patients with CHC.
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12
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Tang Y, Li Y, Yu H, Gao C, Liu L, Xing M, Liu L, Yao P. Quercetin attenuates chronic ethanol hepatotoxicity: implication of "free" iron uptake and release. Food Chem Toxicol 2014; 67:131-8. [PMID: 24569067 DOI: 10.1016/j.fct.2014.02.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 02/09/2014] [Accepted: 02/12/2014] [Indexed: 12/11/2022]
Abstract
Emerging evidence has displayed that oxygen free radicals especially ones promoted by "free" iron play an important role in the development of alcoholic liver disease (ALD). Naturally-occurring quercetin has been reported to prevent ALD and iron overload-induced damage aside from the "free" iron. The purpose was to explore the potential mechanisms by which quercetin arrests alcohol-induced "free" iron disorder. Chronic alcohol (30% of total calories) or iron (0.2%)-fed adult male C57BL/J mice for 15 weeks resulted in significantly elevated levels of hepatic iron, labile iron pool-Fe and serum non-transferrin bound iron, accompanied with sustained oxidative damage. The hepatotoxicity was further exacerbated by ethanol and iron. Quercetin (100 mg/kg. body weight) alleviated the detrimental effects induced by ethanol and/or iron. The expressions of divalent metal transporter 1, zinc transporter member 14, mucolipin 1, transferrin receptor 1 (TfR1) and ferritin were up-regulated by ethanol and/or iron, which were partially normalized by quercetin. Quercetin prevented ethanol-induced hepatotoxicity, which may be partially attributed to the alleviated disorder of bound iron and "free" iron. The significant suppression of ethanol-stimulated molecules for "free" iron uptake and release may contribute to the hepatoprotective effect of quercetin, although TfR1-mediated physiological pathway of iron uptake also played a role.
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Affiliation(s)
- Yuhan Tang
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, State Key Laboratory of Environment Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Yanyan Li
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, State Key Laboratory of Environment Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Haiyan Yu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, State Key Laboratory of Environment Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chao Gao
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, State Key Laboratory of Environment Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Liang Liu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, State Key Laboratory of Environment Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Mingyou Xing
- Department of Infectious Diseases, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Liegang Liu
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, State Key Laboratory of Environment Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ping Yao
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Ministry of Education Key Laboratory of Environment and Health and MOE Key Lab of Environment and Health, Key Laboratory of Environment and Health (Wuhan), Ministry of Environmental Protection, State Key Laboratory of Environment Health (Incubation), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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Gaitán D, Olivares M, Lönnerdal B, Brito A, Pizarro F. Non-heme iron as ferrous sulfate does not interact with heme iron absorption in humans. Biol Trace Elem Res 2012; 150:68-73. [PMID: 22935997 DOI: 10.1007/s12011-012-9496-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 08/10/2012] [Indexed: 10/28/2022]
Abstract
The absorption of heme iron has been described as distinctly different from that of non-heme iron. Moreover, whether heme and non-heme iron compete for absorption has not been well established. Our objective was to investigate the potential competition between heme and non-heme iron as ferrous sulfate for absorption, when both iron forms are ingested on an empty stomach. Twenty-six healthy nonpregnant women were selected to participate in two iron absorption studies using iron radioactive tracers. We obtained the dose-response curve for absorption of 0.5, 10, 20, and 50 mg heme iron doses, as concentrated red blood cells. Then, we evaluated the absorption of the same doses, but additionally we added non-heme iron, as ferrous sulfate, at constant heme/non-heme iron molar ratio (1:1). Finally, we compare the two curves by a two-way ANOVA. Iron sources were administered on an empty stomach. One factor analysis showed that heme iron absorption was diminished just by increasing total heme iron (P < 0.0001). The addition of non-heme iron as ferrous sulfate did not have any effect on heme iron absorption (P = NS). We reported evidence that heme and non-heme iron as ferrous sulfate does not compete for absorption. The mechanism behind the absorption of these iron sources is not clear.
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Affiliation(s)
- Diego Gaitán
- Research Group on Food and Human Nutrition, University of Antioquia, Medellín, Colombia.
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14
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Abstract
Iron metabolism has been intensively examined over the last decade and there are many new players in this field which are worth to be introduced. Since its discovery many studies confirmed role of liver hormone hepcidin as key regulator of iron metabolism and pointed out liver as the central organ of system iron homeostasis. Liver cells receive multiple signals related to iron balance and respond by transcriptional regulation of hepcidin expression. This liver hormone is negative regulator of iron metabolism that represses iron efflux from macrophages, hepatocytes and enterocytes by its binding to iron export protein ferroportin. Ferroportin degradation leads to cellular iron retention and decreased iron availability. At level of a cell IRE/IRP (iron responsive elements/iron responsive proteins) system allows tight regulation of iron assimilation that prevents an excess of free intracellular iron which could lead to oxidative stress and damage of DNA, proteins and lipid membranes by ROS (reactive oxygen species). At the same time IRE/IRP system provides sufficient iron in order to meet the metabolic needs. Recently a significant progress in understanding of iron metabolism has been made and new molecular participants have been characterized. Article gives an overview of the current understanding of iron metabolism: absorption, distribution, cellular uptake, release, and storage. We also discuss mechanisms underlying systemic and cellular iron regulation with emphasis on central regulatory hormone hepcidin.
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Affiliation(s)
- Leida Tandara
- Department of Medical Laboratory Diagnosis, University Hospital Center Split, Split, Croatia.
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15
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The hypoxia-inducible factor-C/EBPα axis controls ethanol-mediated hepcidin repression. Mol Cell Biol 2012; 32:4068-77. [PMID: 22869521 DOI: 10.1128/mcb.00723-12] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Hepcidin is a liver-derived peptide hormone and the master regulator of systemic iron homeostasis. Decreased hepcidin expression is a common feature in alcoholic liver disease (ALD) and in mouse models of ethanol loading. Dysregulation of hepcidin signaling in ALD leads to liver iron deposition, which is a major contributing factor to liver injury. The mechanism by which hepcidin is regulated following ethanol treatment is unclear. An increase in liver hypoxia was observed in an acute ethanol-induced liver injury model. The hypoxic response is controlled by a family of hypoxia-inducible transcription factors (HIFs), which are composed of an oxygen-regulated alpha subunit (HIFα) and a constitutively present beta subunit, aryl hydrocarbon receptor nuclear translocator (HIFβ/Arnt). Disruption of liver HIF function reversed the repression of hepcidin following ethanol loading. Mouse models of liver HIF overexpression demonstrated that both HIF-1α and HIF-2α contribute to hepcidin repression in vivo. Ethanol treatment led to a decrease in CCAAT-enhancer-binding protein alpha (C/EBPα) protein expression in a HIF-dependent manner. Importantly, adenoviral rescue of C/EBPα in vivo ablated the hepcidin repression in response to ethanol treatment or HIF overexpression. These data provide novel insight into the regulation of hepcidin by hypoxia and indicate that targeting HIFs in the liver could be therapeutic in ALD.
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16
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Chen C, Paw BH. Cellular and mitochondrial iron homeostasis in vertebrates. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1823:1459-67. [PMID: 22285816 DOI: 10.1016/j.bbamcr.2012.01.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2011] [Revised: 01/07/2012] [Accepted: 01/07/2012] [Indexed: 02/08/2023]
Abstract
Iron plays an essential role in cellular metabolism and biological processes. However, due to its intrinsic redox activity, free iron is a potentially toxic molecule in cellular biochemistry. Thus, organisms have developed sophisticated ways to import, sequester, and utilize iron. The transferrin cycle is a well-studied iron uptake pathway that is important for most vertebrate cells. Circulating iron can also be imported into cells by mechanisms that are independent of transferrin. Once imported into erythroid cells, iron is predominantly consumed by the mitochondria for the biosynthesis of heme and iron sulfur clusters. This review focuses on canonical transferrin-mediated and the newly discovered, non-transferrin mediated iron uptake pathways, as well as, mitochondrial iron homeostasis in higher eukaryotes. This article is part of a Special Issue entitled: Cell Biology of Metals.
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Affiliation(s)
- Caiyong Chen
- Department of Medicine, Hematology Division, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115, USA
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17
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Maegdefrau U, Arndt S, Kivorski G, Hellerbrand C, Bosserhoff AK. Downregulation of hemojuvelin prevents inhibitory effects of bone morphogenetic proteins on iron metabolism in hepatocellular carcinoma. J Transl Med 2011; 91:1615-23. [PMID: 21863061 DOI: 10.1038/labinvest.2011.123] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Recently, we revealed that bone morphogenetic protein (BMP) 4 is increased in hepatocellular carcinoma (HCC). Furthermore, latest reports described BMPs, in particular BMP6, as important regulators of hepcidin expression in iron homeostasis. Therefore, we aimed to unravel why enhanced BMP expression in HCC patients does not lead to severe changes in iron metabolism. Initial analysis of the BMP4 and BMP6 expression patterns revealed enhanced expression on mRNA and protein level in HCC cell lines and tissue samples compared with primary human hepatocytes (PHHs) and normal liver tissues. However and interestingly, hepcidin expression was reduced in HCC cell lines and tissues. Analysis of BMP6 receptor expression revealed loss of BMP6-specific receptor subunit in HCC. To identify a possible regulatory mechanism causing lack of reaction to BMP4 we analyzed the expression of hemojuvelin (HJV), which is involved in iron metabolism as BMP co-receptor. HJV expression was markedly decreased in HCC cell lines and tissues. HJV promoter analysis revealed potential HNF-1α and snail-binding sites, but functional analysis ruled out that these transcriptional regulators or promoter methylation are the cause of HJV downregulation in HCC. However, we identified AU-rich elements in the HJV 3'-untranslated region and revealed significantly faster decay of HJV mRNA in HCC cells as compared with PHH indicating decreased mRNA-stability as the reason for the loss of HJV expression in HCC.
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Chen J, Enns CA. Hereditary hemochromatosis and transferrin receptor 2. Biochim Biophys Acta Gen Subj 2011; 1820:256-63. [PMID: 21864651 DOI: 10.1016/j.bbagen.2011.07.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2011] [Revised: 07/26/2011] [Accepted: 07/29/2011] [Indexed: 02/08/2023]
Abstract
BACKGROUND Multicellular organisms regulate the uptake of calories, trace elements, and other nutrients by complex feedback mechanisms. In the case of iron, the body senses internal iron stores, iron requirements for hematopoiesis, and inflammatory status, and regulates iron uptake by modulating the uptake of dietary iron from the intestine. Both the liver and the intestine participate in the coordination of iron uptake and distribution in the body. The liver senses inflammatory signals and iron status of the organism and secretes a peptide hormone, hepcidin. Under high iron or inflammatory conditions hepcidin levels increase. Hepcidin binds to the iron transport protein, ferroportin (FPN), promoting FPN internalization and degradation. Decreased FPN levels reduce iron efflux out of intestinal epithelial cells and macrophages into the circulation. Derangements in iron metabolism result in either the abnormal accumulation of iron in the body, or in anemias. The identification of the mutations that cause the iron overload disease, hereditary hemochromatosis (HH), or iron-refractory iron-deficiency anemia has revealed many of the proteins used to regulate iron uptake. SCOPE OF THE REVIEW In this review we discuss recent data concerning the regulation of iron homeostasis in the body by the liver and how transferrin receptor 2 (TfR2) affects this process. MAJOR CONCLUSIONS TfR2 plays a key role in regulating iron homeostasis in the body. GENERAL SIGNIFICANCE The regulation of iron homeostasis is important. One third of the people in the world are anemic. HH is the most common inherited disease in people of Northern European origin and can lead to severe health complications if left untreated. This article is part of a Special Issue entitled Transferrins: Molecular mechanisms of iron transport and disorders.
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Affiliation(s)
- Juxing Chen
- Department of Cell and Developmental Biology L215, Oregon Health & Science University, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, USA
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