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Functional Imaging Using Bioluminescent Reporter Genes in Living Subjects. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00004-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Chen Y, Xu W, Yang H, Shao M, Xu S, Deng J, Gao X, Liu H, Shuai Z, Xu S, Pan F. Serum Levels of Hepcidin in Rheumatoid Arthritis and Its Correlation with Disease Activity and Anemia: A Meta-analysis. Immunol Invest 2020; 50:243-258. [PMID: 32216485 DOI: 10.1080/08820139.2020.1742731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Present studies on serum hepcidin levels in patients with rheumatoid arthritis (RA) are inconsistent. We aimed to synthetically evaluate the relationship between hepcidin and RA, and the correlation of serum hepcidin levels and RA disease activity as well as anemia associated with RA. Multiple electronic databases were searched. Pooled standard mean difference (SMD) with 95% confidence interval (CI) and correlation coefficients between hepcidin levels and rheumatoid factor (RF), disease activity for 28 joints (DAS28), and erythrocyte sedimentation rate (ESR) were calculated. Totally, 13 articles were available for this meta-analysis. The results revealed that serum levels of hepcidin were higher in RA patients compared to healthy controls (SMD = 0.573, 95% CI = 0.317 to 0.829, p < .001); RA patients with anemia had higher serum hepcidin levels than RA patients without anemia (SMD = 0.400, 95% CI = 0.080 to 0.720, p = .014); RA patients with pure ACD had higher serum hepcidin levels than RA patients with ACD and IDA (SMD = 0.658, 95% CI = 0.018 to 1.299, p = .044). Moreover, the result of correlation coefficients identified a significant positive correlation between hepcidin levels and RF, DAS28 as well as ESR. Serum hepcidin levels may be closely associated with the development of RA.
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Affiliation(s)
- Yuting Chen
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei, Anhui, China.,The Key Laboratory of Major Autoimmune Diseases, Anhui Medical University , Hefei, Anhui, China
| | - Wei Xu
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei, Anhui, China.,The Key Laboratory of Major Autoimmune Diseases, Anhui Medical University , Hefei, Anhui, China
| | - Hui Yang
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei, Anhui, China.,The Key Laboratory of Major Autoimmune Diseases, Anhui Medical University , Hefei, Anhui, China
| | - Ming Shao
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei, Anhui, China.,The Key Laboratory of Major Autoimmune Diseases, Anhui Medical University , Hefei, Anhui, China
| | - Shanshan Xu
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei, Anhui, China.,The Key Laboratory of Major Autoimmune Diseases, Anhui Medical University , Hefei, Anhui, China
| | - Jixiang Deng
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei, Anhui, China.,The Key Laboratory of Major Autoimmune Diseases, Anhui Medical University , Hefei, Anhui, China
| | - Xing Gao
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei, Anhui, China.,The Key Laboratory of Major Autoimmune Diseases, Anhui Medical University , Hefei, Anhui, China
| | - Huanhuan Liu
- Department of Clinical Laboratory, The Second Hospital of Anhui Medical University , Hefei, Anhui Province, P.R.China
| | - Zongwen Shuai
- Department of Rheumatism and Immunity, The First Affiliated Hospital of Anhui Medical University , Hefei, Anhui, China
| | - Shengqian Xu
- Department of Rheumatism and Immunity, The First Affiliated Hospital of Anhui Medical University , Hefei, Anhui, China
| | - Faming Pan
- Department of Epidemiology and Biostatistics, School of Public Health, Anhui Medical University , Hefei, Anhui, China.,The Key Laboratory of Major Autoimmune Diseases, Anhui Medical University , Hefei, Anhui, China
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Ćurko-Cofek B, Grubić Kezele T, Barac-Latas V. Hepcidin and metallothioneins as molecular base for sex-dependent differences in clinical course of experimental autoimmune encephalomyelitis in chronic iron overload. Med Hypotheses 2017; 107:51-54. [PMID: 28915963 DOI: 10.1016/j.mehy.2017.07.022] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 07/12/2017] [Accepted: 07/15/2017] [Indexed: 12/24/2022]
Abstract
Multiple sclerosis is a chronic demyelinating disease of the central nervous system characterised by inflammatory and degenerative changes. It is considered that disease arises from the influence of environmental factors on genetically susceptible individuals. Recent researches, using magnetic resonance imaging, connected iron deposits in different brain regions with demyelinating process in multiple sclerosis patients. Although iron is an essential trace element important for many biological functions it could be harmful because iron excess can induce the production of reactive oxygen species, development of oxidative stress and lipid peroxidation which leads to demyelination. In experimental autoimmune encephalomyelitis model, the most common experimental animal model for multiple sclerosis, we recently found that chronic iron overload influences the clinical course of disease in Dark Agouti rats. In female rats iron overload accelerated the onset of disease, while in male rats it accelerated the progression of disease and increased mortality rate. We hypothesize that those differences arise on molecular level in different expression of stress response proteins hepcidin and metallothioneins in male and female iron overloaded rats. They are both upregulated by metal ions in both sexes. Hepcidin is additionally upregulated by estrogen in female rats and therefore causes higher degradation of iron exporter ferroportin and sequestration of iron in the cells, lowering the possibility for the development of oxidative stress. Antioxidative effect of metallothioneins could be increased in female rats because of their ability to reversibly exchange metal ions with the estrogen receptor. In case of iron excess metallothioneins release zinc, which is normally bound to them. Zinc binds to estrogen receptor and leaves metallothioneins binding domains free for iron, causing at least provisional cytoprotective effect. To test this hypothesis, we propose to determine and compare serum levels of hepcidin and estrogen using ELISA essay as well as expression and distribution of acute stress response proteins hepcidin and metallothioneins, iron and estrogen receptor in the brain and spinal cord tissue using immunohistochemistry in control and chronic iron overloaded male and female rats in experimental autoimmune encephalomyelitis model. It would be also possible to perform the same immunohistochemistry in the brain tissue of multiple sclerosis patients post mortem. The results of experiments could contribute to better understanding of cytoprotective mechanisms in chronic iron overload that could have possible therapeutic applications in iron disturbances. In order to elucidate whether common measure of systemic iron status, like ferritin, haemoglobin concentration and transferrin saturation levels, may be used to distinguish physiologic from potentially harmful iron levels in local disease, for example multiple sclerosis and Still's disease, well-designed clinical trials would be of great interest.
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Affiliation(s)
- Božena Ćurko-Cofek
- Department of Physiology and Immunology, Medical Faculty, University of Rijeka, B. Branchetta 20, 51 000 Rijeka, Croatia.
| | - Tanja Grubić Kezele
- Department of Physiology and Immunology, Medical Faculty, University of Rijeka, B. Branchetta 20, 51 000 Rijeka, Croatia
| | - Vesna Barac-Latas
- Department of Physiology and Immunology, Medical Faculty, University of Rijeka, B. Branchetta 20, 51 000 Rijeka, Croatia
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Giorgi G, D'Anna MC, Roque ME. Iron homeostasis and its disruption in mouse lung in iron deficiency and overload. Exp Physiol 2015; 100:1199-216. [DOI: 10.1113/ep085166] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/29/2015] [Indexed: 12/20/2022]
Affiliation(s)
- Gisela Giorgi
- Laboratory of Human Physiology; Department of Biology, Biochemistry and Pharmacy, Instituto de Investigaciones Biológicas y Biomédicas del Sur (INBIOSUR-CONICET); San Juan 670, Universidad Nacional del Sur; Bahía Blanca Argentina
| | - María Cecilia D'Anna
- Laboratory of Human Physiology; Department of Biology, Biochemistry and Pharmacy, Instituto de Investigaciones Biológicas y Biomédicas del Sur (INBIOSUR-CONICET); San Juan 670, Universidad Nacional del Sur; Bahía Blanca Argentina
| | - Marta Elena Roque
- Laboratory of Human Physiology; Department of Biology, Biochemistry and Pharmacy, Instituto de Investigaciones Biológicas y Biomédicas del Sur (INBIOSUR-CONICET); San Juan 670, Universidad Nacional del Sur; Bahía Blanca Argentina
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Buckley SMK, Delhove JMKM, Perocheau DP, Karda R, Rahim AA, Howe SJ, Ward NJ, Birrell MA, Belvisi MG, Arbuthnot P, Johnson MR, Waddington SN, McKay TR. In vivo bioimaging with tissue-specific transcription factor activated luciferase reporters. Sci Rep 2015; 5:11842. [PMID: 26138224 PMCID: PMC4490336 DOI: 10.1038/srep11842] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 06/08/2015] [Indexed: 11/22/2022] Open
Abstract
The application of transcription factor activated luciferase reporter cassettes in vitro is widespread but potential for in vivo application has not yet been realized. Bioluminescence imaging enables non-invasive tracking of gene expression in transfected tissues of living rodents. However the mature immune response limits luciferase expression when delivered in adulthood. We present a novel approach of tissue-targeted delivery of transcription factor activated luciferase reporter lentiviruses to neonatal rodents as an alternative to the existing technology of generating germline transgenic light producing rodents. At this age, neonates acquire immune tolerance to the conditionally responsive luciferase reporter. This simple and transferrable procedure permits surrogate quantitation of transcription factor activity over the lifetime of the animal. We show principal efficacy by temporally quantifying NFκB activity in the brain, liver and lungs of somatotransgenic reporter mice subjected to lipopolysaccharide (LPS)-induced inflammation. This response is ablated in Tlr4(-/-) mice or when co-administered with the anti-inflammatory glucocorticoid analogue dexamethasone. Furthermore, we show the malleability of this technology by quantifying NFκB-mediated luciferase expression in outbred rats. Finally, we use somatotransgenic bioimaging to longitudinally quantify LPS- and ActivinA-induced upregulation of liver specific glucocorticoid receptor and Smad2/3 reporter constructs in somatotransgenic mice, respectively.
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Affiliation(s)
- Suzanne M. K. Buckley
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, 86–96 Chenies Mews, London WC1E 6HX, UK
| | - Juliette M. K. M. Delhove
- Stem Cell Group, Cardiovascular & Cell Sciences Research Institute, St. George’s University of London, Cranmer Terrace, London SW17 0RE, UK
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Dany P. Perocheau
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, 86–96 Chenies Mews, London WC1E 6HX, UK
| | - Rajvinder Karda
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, 86–96 Chenies Mews, London WC1E 6HX, UK
- Faculty of Medicine, Department of Surgery & Cancer, Imperial College, London, UK
| | - Ahad A. Rahim
- Department of Pharmacology, School of Pharmacy, University College London, 29–39 Brunswick Square, London WC1N 1AX, UK
| | - Steven J. Howe
- Wolfson Institute for Gene Therapy, Molecular and Cellular Immunology, Institute of Child Health, University College London, London WC1N 1EH, UK
| | - Natalie J. Ward
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, 86–96 Chenies Mews, London WC1E 6HX, UK
| | - Mark A. Birrell
- Faculty of Medicine, National Heart & Lung Institute, Imperial College, London, UK
| | - Maria G. Belvisi
- Faculty of Medicine, National Heart & Lung Institute, Imperial College, London, UK
| | - Patrick Arbuthnot
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Mark R. Johnson
- Faculty of Medicine, Department of Surgery & Cancer, Imperial College, London, UK
| | - Simon N. Waddington
- Gene Transfer Technology Group, Institute for Women’s Health, University College London, 86–96 Chenies Mews, London WC1E 6HX, UK
- Wits/SAMRC Antiviral Gene Therapy Research Unit, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Tristan R. McKay
- Stem Cell Group, Cardiovascular & Cell Sciences Research Institute, St. George’s University of London, Cranmer Terrace, London SW17 0RE, UK
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Giorgi G, Roque ME. Iron overload induces changes of pancreatic and duodenal divalent metal transporter 1 and prohepcidin expression in mice. Acta Histochem 2014; 116:354-62. [PMID: 24083991 DOI: 10.1016/j.acthis.2013.08.013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 08/21/2013] [Accepted: 08/22/2013] [Indexed: 02/06/2023]
Abstract
It is well known that the iron content of the body is tightly regulated. Iron excess induces adaptive changes that are differentially regulated in each tissue. The pancreas is particularly susceptible to iron-related disorders. We studied the expression and regulation of key iron proteins in the pancreas, duodenum and liver, using an animal model of iron overload (female CF1 mice injected i.p. with iron saccharate, colloidal iron form). Divalent metal transporter 1, prohepcidin and ferritin (pancreas, duodenum, liver) were assessed by immunohistochemistry; divalent metal transporter 1 (pancreas, duodenum) by Western blot. In the iron overloaded mice, prohepcidin expression increased in islets of Langerhans and hepatocytes, and divalent metal transporter 1 expression decreased in cells of islets and in enterocytes. In the iron overloaded mice, ferritin expression decreased in islets of Langerhans and increased in acinar cells; hemosiderin was localized in connective tissue cells. The inverse relationship between divalent metal transporter 1 and prohepcidin may indicate a negative regulation by hepcidin, and hence reduction of iron stores in islets of Langerhans. Our data showed that in iron overloaded mice model, induced by colloidal iron form, a coordinated expression of key iron proteins in the pancreas, duodenum and liver may occur. Further research will be necessary to determine the adaptive responses induced by iron in the pancreas.
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Bertinato J, Aroche C, Plouffe LJ, Lee M, Murtaza Z, Kenney L, Lavergne C, Aziz A. Diet-induced obese rats have higher iron requirements and are more vulnerable to iron deficiency. Eur J Nutr 2013; 53:885-95. [PMID: 24096586 DOI: 10.1007/s00394-013-0592-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2013] [Accepted: 09/24/2013] [Indexed: 01/27/2023]
Abstract
PURPOSE Since obesity is associated with poorer iron status, the effects of diet-induced obesity on iron status and iron-regulatory pathways were examined. METHODS Weanling male diet-induced obese sensitive (n = 12/diet group) and resistant (n = 12/diet group) rats were fed one of four high-fat, high-energy diets supplemented with 5 (5Fe, low), 15 (15Fe, marginal), 35 (35Fe, normal) or 70 (70Fe, high) mg iron/kg diet for 12 weeks. At the end of the study, rats in each diet group were categorised as obese (>19 %) or lean (<17 %) based on percentage body fat. RESULTS Obese rats gained more weight, had larger total lean mass, consumed more food and showed greater feed efficiency compared with lean rats. Obese rats fed the 5Fe and 15Fe diets had poorer iron status than lean rats fed the same diet. Obese 5Fe rats had lower serum iron and more severe iron-deficiency anaemia. Obese 15Fe rats had lower mean corpuscular haemoglobin and liver iron concentrations. Hepcidin mRNA expression in liver and adipose tissue was similar for obese and lean rats. Iron concentration and content of the iron transporters divalent metal transporter 1 and ferroportin 1 in duodenal mucosa were also similar. CONCLUSIONS Obese rats that were larger, regardless of adiposity, had higher iron requirements compared with lean rats that appeared independent of hepcidin, inflammation and intestinal iron absorption. Higher iron requirements may have resulted from larger accretion of body mass and blood volume. Greater food consumption did not compensate for the higher iron needs, indicating increased susceptibility to iron deficiency.
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Affiliation(s)
- Jesse Bertinato
- Nutrition Research Division, Health Products and Food Branch, Health Canada, Sir Frederick G. Banting Research Centre, 251 Sir Frederick Banting Driveway, PL 2203E, Ottawa, ON, K1A 0K9, Canada,
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Ramos E, Kautz L, Rodriguez R, Hansen M, Gabayan V, Ginzburg Y, Roth MP, Nemeth E, Ganz T. Evidence for distinct pathways of hepcidin regulation by acute and chronic iron loading in mice. Hepatology 2011; 53:1333-41. [PMID: 21480335 PMCID: PMC3074982 DOI: 10.1002/hep.24178] [Citation(s) in RCA: 183] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
UNLABELLED In response to iron loading, hepcidin synthesis is homeostatically increased to limit further absorption of dietary iron and its release from stores. Mutations in HFE, transferrin receptor 2 (Tfr2), hemojuvelin (HJV), or bone morphogenetic protein 6 (BMP6) prevent appropriate hepcidin response to iron, allowing increased absorption of dietary iron, and eventually iron overload. To understand the role each of these proteins plays in hepcidin regulation by iron, we analyzed hepcidin messenger RNA (mRNA) responsiveness to short and long-term iron challenge in iron-depleted Hfe, Tfr2, Hjv, and Bmp6 mutant mice. After 1-day (acute) iron challenge, Hfe(-/-) mice showed a smaller hepcidin increase than their wild-type strain-matched controls, Bmp6(-/-) mice showed nearly no increase, and Tfr2 and Hjv mutant mice showed no increase in hepcidin expression, indicating that all four proteins participate in hepcidin regulation by acute iron changes. After a 21-day (chronic) iron challenge, Hfe and Tfr2 mutant mice increased hepcidin expression to nearly wild-type levels, but a blunted increase of hepcidin was seen in Bmp6(-/-) and Hjv(-/-) mice. BMP6, whose expression is also regulated by iron, may mediate hepcidin regulation by iron stores. None of the mutant strains (except Bmp6(-/-) mice) had impaired BMP6 mRNA response to chronic iron loading. CONCLUSION TfR2, HJV, BMP6, and, to a lesser extent, HFE are required for the hepcidin response to acute iron loading, but are partially redundant for hepcidin regulation during chronic iron loading and are not involved in the regulation of BMP6 expression. Our findings support a model in which acute increases in holotransferrin concentrations transmitted through HFE, TfR2, and HJV augment BMP receptor sensitivity to BMPs. A distinct regulatory mechanism that senses hepatic iron may modulate hepcidin response to chronic iron loading.
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Affiliation(s)
- Emilio Ramos
- Department of Chemistry and Biochemistry, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Léon Kautz
- Inserm, U563, Toulouse, Université de Toulouse, UPS, Centre de Physiopathologie de Toulouse Purpan and Institut Biomédical de Toulouse, France
| | - Richard Rodriguez
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Michael Hansen
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Victoria Gabayan
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, USA
| | | | - Marie-Paule Roth
- Inserm, U563, Toulouse, Université de Toulouse, UPS, Centre de Physiopathologie de Toulouse Purpan and Institut Biomédical de Toulouse, France
| | - Elizabeta Nemeth
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, USA
| | - Tomas Ganz
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, USA, Department of Pathology, David Geffen School of Medicine, University of California, Los Angeles, USA
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Abstract
Under evolutionary pressure to counter the toxicity of iron and to maintain adequate iron supply for hemoglobin synthesis and essential metabolic functions, humans and other vertebrates have effective mechanisms to conserve iron and to regulate its concentration, storage, and distribution in tissues. The iron-regulatory hormone hepcidin, first described 10 years ago, and its receptor and iron channel ferroportin control the dietary absorption, storage, and tissue distribution of iron. Hepcidin causes ferroportin internalization and degradation, thereby decreasing iron transfer into blood plasma from the duodenum, from macrophages involved in recycling senescent erythrocytes, and from iron-storing hepatocytes. Hepcidin is feedback regulated by iron concentrations in plasma and the liver and by erythropoietic demand for iron. Genetic malfunctions affecting the hepcidin-ferroportin axis are a main cause of iron overload disorders but can also cause iron-restricted anemias. Modulation of hepcidin and ferroportin expression during infection and inflammation couples iron metabolism to host defense and decreases iron availability to invading pathogens. This response also restricts the iron supply to erythropoietic precursors and may cause or contribute to the anemia associated with infections and inflammatory disorders.
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Truksa J, Gelbart T, Peng H, Beutler E, Beutler B, Lee P. Suppression of the hepcidin-encoding gene Hamp permits iron overload in mice lacking both hemojuvelin and matriptase-2/TMPRSS6. Br J Haematol 2009; 147:571-81. [PMID: 19751239 DOI: 10.1111/j.1365-2141.2009.07873.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Hepcidin, the master regulator of enteric iron absorption, is controlled by the opposing effects of pathways activated in response to iron excess or iron attenuation. Iron excess is regulated through a pathway involving the cell surface receptor hemojuvelin (HFE2) that stimulates expression of the hepcidin encoding gene (HAMP). Iron attenuation is countered through a pathway involving the hepatocyte-specific plasma membrane protease matriptase-2 encoded by TMPRSS6, leading to suppression of HAMP expression. The non-redundant function of hemojuvelin and matriptase-2 has been deduced from the phenotype imparted by mutations of HFE2 and TMPRSS6, which cause iron excess and iron deficiency respectively. Hemojuvelin is positioned to be the ideal substrate for matriptase-2. To examine the relationship between hemojuvelin and matriptase-2 in vivo, we crossed mice lacking the protease domain of matriptase-2 with mice lacking hemojuvelin. Mice lacking functional matriptase-2 and hemojuvelin exhibited low Hamp (Hamp1) expression, high serum and liver iron, and high transferrin saturation. Surprisingly, the double mutant mice also exhibited lower levels of iron in the heart compared to hemojuvelin-deficient mice, demonstrating a possible cardioprotective effect resulting from the loss of matriptase-2. This phenotype is consistent with hemojuvelin being a major substrate for matriptase-2/TMPRSS6 protease activity.
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Affiliation(s)
- Jaroslav Truksa
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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Vecchi C, Montosi G, Zhang K, Lamberti I, Duncan SA, Kaufman RJ, Pietrangelo A. ER stress controls iron metabolism through induction of hepcidin. Science 2009; 325:877-80. [PMID: 19679815 PMCID: PMC2923557 DOI: 10.1126/science.1176639] [Citation(s) in RCA: 240] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hepcidin is a peptide hormone that is secreted by the liver and controls body iron homeostasis. Hepcidin overproduction causes anemia of inflammation, whereas its deficiency leads to hemochromatosis. Inflammation and iron are known extracellular stimuli for hepcidin expression. We found that endoplasmic reticulum (ER) stress also induces hepcidin expression and causes hypoferremia and spleen iron sequestration in mice. CREBH (cyclic AMP response element-binding protein H), an ER stress-activated transcription factor, binds to and transactivates the hepcidin promoter. Hepcidin induction in response to exogenously administered toxins or accumulation of unfolded protein in the ER is defective in CREBH knockout mice, indicating a role for CREBH in ER stress-regulated hepcidin expression. The regulation of hepcidin by ER stress links the intracellular response involved in protein quality control to innate immunity and iron homeostasis.
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Affiliation(s)
- Chiara Vecchi
- Center for Hemochromatosis, Department of Internal Medicine, University Hospital Policlinico di Modena, Modena, Italy
| | - Giuliana Montosi
- Center for Hemochromatosis, Department of Internal Medicine, University Hospital Policlinico di Modena, Modena, Italy
| | - Kezhong Zhang
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Igor Lamberti
- Center for Hemochromatosis, Department of Internal Medicine, University Hospital Policlinico di Modena, Modena, Italy
| | - Stephen A. Duncan
- Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Randal J. Kaufman
- Howard Hughes Medical Institute, Departments of Biological Chemistry and Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI 48109–0650, USA
| | - Antonello Pietrangelo
- Center for Hemochromatosis, Department of Internal Medicine, University Hospital Policlinico di Modena, Modena, Italy
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Weiss G. Iron metabolism in the anemia of chronic disease. Biochim Biophys Acta Gen Subj 2009; 1790:682-93. [DOI: 10.1016/j.bbagen.2008.08.006] [Citation(s) in RCA: 192] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Revised: 07/27/2008] [Accepted: 08/14/2008] [Indexed: 02/08/2023]
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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: 359] [Impact Index Per Article: 23.9] [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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Abstract
Erythrocytes require iron to perform their duty as oxygen carriers. Mammals have evolved a mechanism to maintain systemic iron within an optimal range that fosters erythroid development and function while satisfying other body iron needs. This chapter reviews erythroid iron uptake and utilization as well as systemic factors that influence iron availability. One of these factors is hepcidin, a circulating peptide hormone that maintains iron homeostasis. Elevated levels of hepcidin in the bloodstream effectively shut off iron absorption by disabling the iron exporter ferroportin. Conversely, low levels of circulating hepcidin allow ferroportin to export iron into the bloodstream. Aberrations in hepcidin expression or responsiveness to hepcidin result in disorders of iron deficiency and iron overload. It is clear that erythroid precursors communicate their iron needs to the liver to influence the production of hepcidin and thus the amount of iron available for use. However, the mechanism by which erythroid cells accomplish this remains unclear and is an area of active investigation.
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Affiliation(s)
- Diedra M Wrighting
- Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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Truksa J, Peng H, Lee P, Beutler E. Different regulatory elements are required for response of hepcidin to interleukin-6 and bone morphogenetic proteins 4 and 9. Br J Haematol 2007; 139:138-47. [PMID: 17854319 DOI: 10.1111/j.1365-2141.2007.06728.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hepcidin is a major regulator of iron homeostasis. Hepcidin expression is upregulated by inflammatory cytokines, particularly interleukin (IL)-6 and even more potently by the bone morphogenetic proteins 2, 4 and 9 (BMP-2, BMP-4 and BMP-9). This study showed that the regulation of hepcidin expression by IL-6 and BMPs occurs through distinct regulatory elements. The induction of hepcidin by BMPs requires at least two regions of the Hamp1 promoter, one between 140-260 bp and the other between 1.6-2.0 kb upstream of the start of translation. Reporter constructs including 1.6-2.0 kb of the Hamp1 promoter were induced >16-fold by BMPs whereas a 260 bp reporter Hamp1 promoter construct was induced only two- to threefold. The distal 1.6-2.0 kb region appeared to contain several different BMP-responsive elements, as incremental lengthening of the promoter construct in this region produced gradual escalation of BMP-responsiveness. In contrast, the IL-6 response required only the proximal 260 bp Hamp1 promoter region. Furthermore, there were no regulatory elements located in the non-coding or coding regions of Hamp1 and activation of the Hamp1 promoter was absent or markedly reduced in cells of non-hepatic origin.
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Affiliation(s)
- Jaroslav Truksa
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA 92037, USA
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Truksa J, Lee P, Peng H, Flanagan J, Beutler E. The distal location of the iron responsive region of the hepcidin promoter. Blood 2007; 110:3436-7. [PMID: 17644736 PMCID: PMC2200907 DOI: 10.1182/blood-2007-05-091108] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The response of hepcidin transcription to iron has been repeatedly documented in living mice, but it is difficult to demonstrate the response in ex vivo systems. We have hydrodynamically transfected mice with plasmid constructs composed of a murine hepcidin 1 promoter and fragments of the promoter fused to a firefly luciferase reporter. This method enabled us to quantitate the response of the hepcidin promoter to short-term feeding of a high-iron diet to mice that have been maintained on an iron-deficient diet. We show that the region of the promoter between 1.6 Kb and 1.8 Kb upstream from the start of translation is essential for the response to iron. The promoter region between -260 bp and -1.6 Kb is not essential for the iron responsiveness of hepcidin promoter. The iron-responsive region that we have mapped is the same region required for the in vitro response of HepG2 cells to stimulation with bone morphogenetic proteins and differs from the LPS/IL-6 responsive area.
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Affiliation(s)
- Jaroslav Truksa
- Department of Molecular and Experimental Medicine, Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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