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Paluschinski M, Kordes C, Vucur M, Buettner V, Roderburg C, Xu HC, Shinte PV, Lang PA, Luedde T, Castoldi M. Differential Modulation of miR-122 Transcription by TGFβ1/BMP6: Implications for Nonresolving Inflammation and Hepatocarcinogenesis. Cells 2023; 12:1955. [PMID: 37566034 PMCID: PMC10416984 DOI: 10.3390/cells12151955] [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: 06/30/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/12/2023] Open
Abstract
Chronic inflammation is widely recognized as a significant factor that promotes and worsens the development of malignancies, including hepatocellular carcinoma. This study aimed to explore the potential role of microRNAs in inflammation-associated nonresolving hepatocarcinogenesis. By conducting a comprehensive analysis of altered microRNAs in animal models with liver cancer of various etiologies, we identified miR-122 as the most significantly downregulated microRNA in the liver of animals with inflammation-associated liver cancer. Although previous research has indicated the importance of miR-122 in maintaining hepatocyte function, its specific role as either the trigger or the consequence of underlying diseases remains unclear. Through extensive analysis of animals and in vitro models, we have successfully demonstrated that miR-122 transcription is differentially regulated by the immunoregulatory cytokines, by the transforming growth factor-beta 1 (TGFβ1), and the bone morphogenetic protein-6 (BMP6). Furthermore, we presented convincing evidence directly linking reduced miR-122 transcription to inflammation and in chronic liver diseases. The results of this study strongly suggest that prolonged activation of pro-inflammatory signaling pathways, leading to disruption of cytokine-mediated regulation of miR-122, may significantly contribute to the onset and exacerbation of chronic liver disease.
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Affiliation(s)
- Martha Paluschinski
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany; (M.P.); (C.K.); (M.V.); (V.B.); (C.R.); (T.L.)
| | - Claus Kordes
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany; (M.P.); (C.K.); (M.V.); (V.B.); (C.R.); (T.L.)
| | - Mihael Vucur
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany; (M.P.); (C.K.); (M.V.); (V.B.); (C.R.); (T.L.)
| | - Veronika Buettner
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany; (M.P.); (C.K.); (M.V.); (V.B.); (C.R.); (T.L.)
| | - Christoph Roderburg
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany; (M.P.); (C.K.); (M.V.); (V.B.); (C.R.); (T.L.)
| | - Haifeng C. Xu
- Institute for Molecular Medicine II, Medical Faculty, Heinrich-Heine University Hospital, 40225 Dusseldorf, Germany; (H.C.X.); (P.V.S.); (P.A.L.)
| | - Prashant V. Shinte
- Institute for Molecular Medicine II, Medical Faculty, Heinrich-Heine University Hospital, 40225 Dusseldorf, Germany; (H.C.X.); (P.V.S.); (P.A.L.)
| | - Philipp A. Lang
- Institute for Molecular Medicine II, Medical Faculty, Heinrich-Heine University Hospital, 40225 Dusseldorf, Germany; (H.C.X.); (P.V.S.); (P.A.L.)
| | - Tom Luedde
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany; (M.P.); (C.K.); (M.V.); (V.B.); (C.R.); (T.L.)
| | - Mirco Castoldi
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich Heine University Dusseldorf, 40225 Dusseldorf, Germany; (M.P.); (C.K.); (M.V.); (V.B.); (C.R.); (T.L.)
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Atorvastatin Inhibits Ferroptosis of H9C2 Cells by regulatingSMAD7/Hepcidin Expression to Improve Ischemia-Reperfusion Injury. Cardiol Res Pract 2022; 2022:3972829. [PMID: 36398315 PMCID: PMC9666047 DOI: 10.1155/2022/3972829] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 10/27/2022] [Indexed: 11/09/2022] Open
Abstract
Background Ferroptosis plays a key role in cardiomyopathy. Atorvastatin (ATV) has a protective effect on ischemia-reperfusion (I/R) cardiomyopathy. The purpose of this study is to elucidate the mechanism of ATV in I/R injury. Methods H9C2 cells and cardiomyopathy rats were induced by hypoxia/reoxygenation (H/R) and I/R to construct in vitro and in vivo models. Cell viability was determined by CCK8. Cardiac histopathology was observed by HE staining. Transmission electron microscope (TEM) was used to observe the mitochondrial morphology. The reactive oxygen species (ROS) content in cells was analyzed by the biochemical method. ELISA was conducted to calculate the concentrations of total iron/Fe2+ and hepcidin. The expression of ferroptosis and SMAD pathway-related genes were detected by qPCR. Western blot was performed to detect the expression levels of ferroptosis and SMAD pathway-related proteins. Results In H9C2 cells, ATV reversed the decline in cell viability, mitochondrial shrinkage, and ROS elevation induced by erastin or H/R. The concentration of total iron and Fe2+ in H/R-induced H9C2 cells increased, and the protein expression of FPN1 decreased. After ATV treatment, the concentration of total iron and Fe2+ decreased, and the protein expression of FPN1 increased. The expression of the SMAD7 gene in H/R-induced H9C2 cells decreased, and the expression of the hepcidin gene increased, which were reversed by ATV. When SMAD7 was knocked down, ATV treatment failed to produce the above effect. ATV also improved ferroptosis in I/R rat myocardium through the SMAD7/hepcidin pathway. Conclusions ATV reversed the decline in H9C2 cell viability, mitochondrial shrinkage, and ROS elevation, and improved the myocardium ferroptosis through the SMAD7/hepcidin pathway in I/R rat.
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Erythroid overproduction of erythroferrone causes iron overload and developmental abnormalities in mice. Blood 2022; 139:439-451. [PMID: 34614145 PMCID: PMC8777203 DOI: 10.1182/blood.2021014054] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 10/04/2021] [Indexed: 02/08/2023] Open
Abstract
The hormone erythroferrone (ERFE) is produced by erythroid cells in response to hemorrhage, hypoxia, or other erythropoietic stimuli, and it suppresses the hepatic production of the iron-regulatory hormone hepcidin, thereby mobilizing iron for erythropoiesis. Suppression of hepcidin by ERFE is believed to be mediated by interference with paracrine bone morphogenetic protein (BMP) signaling that regulates hepcidin transcription in hepatocytes. In anemias with ineffective erythropoiesis, ERFE is pathologically overproduced, but its contribution to the clinical manifestations of these anemias is not well understood. We generated 3 lines of transgenic mice with graded erythroid overexpression of ERFE and found that they developed dose-dependent iron overload, impaired hepatic BMP signaling, and relative hepcidin deficiency. These findings add to the evidence that ERFE is a mediator of iron overload in conditions in which ERFE is overproduced, including anemias with ineffective erythropoiesis. At the highest levels of ERFE overexpression, the mice manifested decreased perinatal survival, impaired growth, small hypofunctional kidneys, decreased gonadal fat depots, and neurobehavioral abnormalities, all consistent with impaired organ-specific BMP signaling during development. Neutralizing excessive ERFE in congenital anemias with ineffective erythropoiesis may not only prevent iron overload but may have additional benefits for growth and development.
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Saad HKM, Abd Rahman AA, Ab Ghani AS, Taib WRW, Ismail I, Johan MF, Al-Wajeeh AS, Al-Jamal HAN. Activation of STAT and SMAD Signaling Induces Hepcidin Re-Expression as a Therapeutic Target for β-Thalassemia Patients. Biomedicines 2022; 10:biomedicines10010189. [PMID: 35052868 PMCID: PMC8773737 DOI: 10.3390/biomedicines10010189] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/11/2022] [Accepted: 01/12/2022] [Indexed: 01/27/2023] Open
Abstract
Iron homeostasis is regulated by hepcidin, a hepatic hormone that controls dietary iron absorption and plasma iron concentration. Hepcidin binds to the only known iron export protein, ferroportin (FPN), which regulates its expression. The major factors that implicate hepcidin regulation include iron stores, hypoxia, inflammation, and erythropoiesis. When erythropoietic activity is suppressed, hepcidin expression is hampered, leading to deficiency, thus causing an iron overload in iron-loading anemia, such as β-thalassemia. Iron overload is the principal cause of mortality and morbidity in β-thalassemia patients with or without blood transfusion dependence. In the case of thalassemia major, the primary cause of iron overload is blood transfusion. In contrast, iron overload is attributed to hepcidin deficiency and hyperabsorption of dietary iron in non-transfusion thalassemia. Beta-thalassemia patients showed marked hepcidin suppression, anemia, iron overload, and ineffective erythropoiesis (IE). Recent molecular research has prompted the discovery of new diagnostic markers and therapeutic targets for several diseases, including β-thalassemia. In this review, signal transducers and activators of transcription (STAT) and SMAD (structurally similar to the small mothers against decapentaplegic in Drosophila) pathways and their effects on hepcidin expression have been discussed as a therapeutic target for β-thalassemia patients. Therefore, re-expression of hepcidin could be a therapeutic target in the management of thalassemia patients. Data from 65 relevant published experimental articles on hepcidin and β-thalassemia between January 2016 and May 2021 were retrieved by using PubMed and Google Scholar search engines. Published articles in any language other than English, review articles, books, or book chapters were excluded.
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Affiliation(s)
- Hanan Kamel M. Saad
- School of Biomedicine, Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Kuala Nerus 21300, Terengganu, Malaysia; (H.K.M.S.); (W.R.W.T.); (I.I.)
| | - Alawiyah Awang Abd Rahman
- Pathology Department, Hospital Sultanah Nur Zahirah, Kuala Terengganu 20400, Terengganu, Malaysia; (A.A.A.R.); (A.S.A.G.)
| | - Azly Sumanty Ab Ghani
- Pathology Department, Hospital Sultanah Nur Zahirah, Kuala Terengganu 20400, Terengganu, Malaysia; (A.A.A.R.); (A.S.A.G.)
| | - Wan Rohani Wan Taib
- School of Biomedicine, Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Kuala Nerus 21300, Terengganu, Malaysia; (H.K.M.S.); (W.R.W.T.); (I.I.)
| | - Imilia Ismail
- School of Biomedicine, Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Kuala Nerus 21300, Terengganu, Malaysia; (H.K.M.S.); (W.R.W.T.); (I.I.)
| | - Muhammad Farid Johan
- Department of Haematology, School of Medical Sciences, Universiti Sains Malaysia, Kubang Kerian 16150, Kelatan, Malaysia;
| | | | - Hamid Ali Nagi Al-Jamal
- School of Biomedicine, Faculty of Health Sciences, Universiti Sultan Zainal Abidin, Kuala Nerus 21300, Terengganu, Malaysia; (H.K.M.S.); (W.R.W.T.); (I.I.)
- Correspondence: ; Tel.: +60-1747-29012
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Fisher AL, Babitt JL. Coordination of iron homeostasis by bone morphogenetic proteins: Current understanding and unanswered questions. Dev Dyn 2022; 251:26-46. [PMID: 33993583 PMCID: PMC8594283 DOI: 10.1002/dvdy.372] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 04/15/2021] [Accepted: 05/07/2021] [Indexed: 01/19/2023] Open
Abstract
Iron homeostasis is tightly regulated to balance the iron requirement for erythropoiesis and other vital cellular functions, while preventing cellular injury from iron excess. The liver hormone hepcidin is the master regulator of systemic iron balance by controlling the degradation and function of the sole known mammalian iron exporter ferroportin. Liver hepcidin expression is coordinately regulated by several signals that indicate the need for more or less iron, including plasma and tissue iron levels, inflammation, and erythropoietic drive. Most of these signals regulate hepcidin expression by modulating the activity of the bone morphogenetic protein (BMP)-SMAD pathway, which controls hepcidin transcription. Genetic disorders of iron overload and iron deficiency have identified several hepatocyte membrane proteins that play a critical role in mediating the BMP-SMAD and hepcidin regulatory response to iron. However, the precise molecular mechanisms by which serum and tissue iron levels are sensed to regulate BMP ligand production and promote the physical and/or functional interaction of these proteins to modulate SMAD signaling and hepcidin expression remain uncertain. This critical commentary will focus on the current understanding and key unanswered questions regarding how the liver senses iron levels to regulate BMP-SMAD signaling and thereby hepcidin expression to control systemic iron homeostasis.
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Affiliation(s)
| | - Jodie L Babitt
- Corresponding author: Jodie L Babitt, Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA. Mailing address: 185 Cambridge St., CPZN-8208, Boston, MA 02114. Telephone: +1 (617) 643-3181.
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Epigallocatechin-3-Gallate Suppresses BMP-6-Mediated SMAD1/5/8 Transactivation of Hepcidin Gene by Inducing SMILE in Hepatocytes. Antioxidants (Basel) 2021; 10:antiox10101590. [PMID: 34679725 PMCID: PMC8533173 DOI: 10.3390/antiox10101590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/27/2021] [Accepted: 10/09/2021] [Indexed: 01/01/2023] Open
Abstract
Hepcidin, a major regulator of systemic iron homeostasis, is mainly induced in hepatocytes by activating bone morphogenetic protein 6 (BMP-6) signaling in response to changes in the iron status. Small heterodimer partner-interacting leucine zipper protein (SMILE), a polyphenol-inducible transcriptional co-repressor, regulates hepatic gluconeogenesis and lipogenesis. Here, we examine the epigallocatechin-3-gallate (EGCG) effect on BMP-6-mediated SMAD1/5/8 transactivation of the hepcidin gene. EGCG treatment significantly decreased BMP-6-induced hepcidin gene expression and secretion in hepatocytes, which, in turn, abated ferroportin degradation. SMILE overexpression significantly decreased BMP receptor-induced hepcidin promoter activity. SMILE overexpression also significantly suppressed BMP-6-mediated induction of hepcidin mRNA and its secretion in HepG2 and AML12 cells. EGCG treatment inhibited BMP-6-mediated hepcidin gene expression and secretion, which were significantly reversed by SMILE knockdown in hepatocytes. Interestingly, SMILE physically interacted with SMAD1 in the nucleus and significantly blocked DNA binding of the SMAD complex to the BMP-response element on the hepcidin gene promoter. Taken together, these findings suggest that SMILE is a novel transcriptional repressor of BMP-6-mediated hepcidin gene expression, thus contributing to the control of iron homeostasis.
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The role of iron homeostasis in remodeling immune function and regulating inflammatory disease. Sci Bull (Beijing) 2021; 66:1806-1816. [PMID: 36654387 DOI: 10.1016/j.scib.2021.02.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Revised: 12/31/2020] [Accepted: 01/28/2021] [Indexed: 02/03/2023]
Abstract
The essential trace element iron regulates a wide range of biological processes in virtually all living organisms. Because both iron deficiency and iron overload can lead to various pathological conditions, iron homeostasis is tightly regulated, and understanding this complex process will help pave the way to developing new therapeutic strategies for inflammatory disease. In recent years, significant progress has been made with respect to elucidating the roles of iron and iron-related genes in the development and maintenance of the immune system. Here, we review the timing and mechanisms by which systemic and cellular iron metabolism are regulated during the inflammatory response and during infectious disease, processes in which both the host and the pathogen compete for iron. We also discuss the evidence and implications that immune cells such as macrophages, T cells, and B cells require sufficient amounts of iron for their proliferation and for mediating their effector functions, in which iron serves as a co-factor in toll-like receptor 4 (TLR4) signaling, mitochondrial respiration, posttranslational regulation, and epigenetic modification. In addition, we discuss the therapeutic implications of targeting ferroptosis, iron homeostasis and/or iron metabolism with respect to conferring protection against pathogen infection, controlling inflammation, and improving the efficacy of immunotherapy.
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8
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Colucci S, Marques O, Altamura S. 20 years of Hepcidin: How far we have come. Semin Hematol 2021; 58:132-144. [PMID: 34389105 DOI: 10.1053/j.seminhematol.2021.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/12/2021] [Accepted: 05/31/2021] [Indexed: 12/20/2022]
Abstract
Twenty years ago the discovery of hepcidin deeply changed our understanding of the regulation of systemic iron homeostasis. It is now clear that hepcidin orchestrates systemic iron levels by controlling the amount of iron exported into the bloodstream through ferroportin. Hepcidin expression is increased in situations where systemic iron levels should be reduced, such as in iron overload and infection. Conversely, hepcidin is repressed during iron deficiency, hypoxia or expanded erythropoiesis, to increase systemic iron availability and sustain erythropoiesis. In this review, we will focus on molecular mechanisms of hepcidin regulation and on the pathological consequences of their disruption.
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Affiliation(s)
- Silvia Colucci
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Heidelberg, Germany.; Molecular Medicine Partnership Unit, EMBL and University of Heidelberg, Heidelberg, Germany
| | - Oriana Marques
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Heidelberg, Germany.; Molecular Medicine Partnership Unit, EMBL and University of Heidelberg, Heidelberg, Germany
| | - Sandro Altamura
- Department of Pediatric Hematology, Oncology and Immunology - University of Heidelberg, Heidelberg, Germany.; Molecular Medicine Partnership Unit, EMBL and University of Heidelberg, Heidelberg, Germany..
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Banerjee S, Katiyar P, Kumar L, Kumar V, Saini SS, Krishnan V, Sircar D, Roy P. Black pepper prevents anemia of inflammation by inhibiting hepcidin over-expression through BMP6-SMAD1/ IL6-STAT3 signaling pathway. Free Radic Biol Med 2021; 168:189-202. [PMID: 33771600 DOI: 10.1016/j.freeradbiomed.2021.03.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/14/2021] [Accepted: 03/17/2021] [Indexed: 01/03/2023]
Abstract
Hepcidin, a circulatory hepatic peptide hormone, is associated with systemic iron homeostasis. Inflammation leads to an increase in hepcidin expression, which dysregulates body iron level. The related disorder, anemia of inflammation, is the second most prevalent anemia-related disorder worldwide. In the present study, we conducted in vitro and in vivo studies to evaluate the effect of black pepper (BP) and its major bioactive alkaloid, piperine, on anemia of inflammation. The initial in vitro study using human hepatocyte cell line, HepG2, confirmed that among different black pepper extracts: methanol (BPME), ethanol (BPEE) and aqueous (BPAE), BPME to be most effective in downregulating transcription of hepcidin gene. Further, BPME and piperine significantly downregulated hepcidin protein expression at 200 μg/ml and 100 μM concentrations, respectively. In the next phase, BPME and piperine were found to significantly attenuate BMP-6 and IL-6 induced hepcidin overexpression by downregulating the increased level of pSMAD1 and pSTAT3 proteins, respectively. For in vivo study, we first subcutaneously injected male BALB/c mice with oil of turpentine, thrice within a period of two weeks, in order to enhance the expression of hepcidin. After that, the intraperitoneal administration of BPME and piperine at 70 and 25 mg/kg body weight, respectively, on alternate days for a period of another two weeks resulted in downregulation of hepcidin overexpression in diseased mice, as confirmed by RT-PCR and immunoblot analysis. The histopathology of liver tissue confirmed increased iron bioavailability in BPME and piperine treated animals. The molecular docking-based interaction studies demonstrated the binding potential of piperine with SMAD1 and STAT3 proteins. The binding patterns supported the proposed inhibition of hepcidin activating proteins. All together, these findings suggest black pepper as a therapeutic candidate for the treatment of anemia of inflammation.
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Affiliation(s)
- Somesh Banerjee
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
| | - Parul Katiyar
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
| | - Lokesh Kumar
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
| | - Vijay Kumar
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, Faridabad, 121001, Haryana, India.
| | - Shashank Sagar Saini
- Plant Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
| | - Vengadesan Krishnan
- Laboratory of Structural Microbiology, Regional Centre for Biotechnology, Faridabad, 121001, Haryana, India.
| | - Debabrata Sircar
- Plant Molecular Biology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
| | - Partha Roy
- Molecular Endocrinology Laboratory, Department of Biotechnology, Indian Institute of Technology Roorkee, Roorkee, 247667, Uttarakhand, India.
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Wang J, Xia C, Sharma A, Gaba GS, Shabaz M. Chest CT Findings and Differential Diagnosis of Mycoplasma pneumoniae Pneumonia and Mycoplasma pneumoniae Combined with Streptococcal Pneumonia in Children. JOURNAL OF HEALTHCARE ENGINEERING 2021; 2021:8085530. [PMID: 34221302 PMCID: PMC8219438 DOI: 10.1155/2021/8085530] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/22/2021] [Accepted: 06/02/2021] [Indexed: 02/07/2023]
Abstract
BACKGROUND In this day and age, 17% of children less than 5 years of age died of pneumonia; it is the common cause of children death. It is one of the main children respiratory infectious diseases, i.e., mycoplasma pneumonia (MP). The imaging examination can be adopted to quickly observe the morphology and scope of the pulmonary lesions and know the effect of disease treatment and subsequent changes in the disease in order to provide a basis for treatment. Therefore, the most commonly applied technology for detecting pneumonia in children is imaging technology, including chest X-ray and CT. OBJECTIVES The main objective of the work is to investigate the chest computed tomography (CT) findings of children patients with Mycoplasma pneumoniae pneumonia (MPP) and MP combined with streptococcal pneumonia (SP). The mixed infection of MP and SP is very common clinically, and the diagnosis of this type of mixed pneumonia is a critical research topic faced by pediatric respiratory physicians. The comparison is done on the incidence of bronchial and pulmonary interstitial lesions, the degree of lymph node enlargement, the volume and depth of pleural effusion, and the location and morphology of the pulmonary lesions in the chest CT images of children patients from the two groups. METHODS There were comparisons on the incidence of bronchial and pulmonary interstitial lesions, the degree of lymph node enlargement, the volume and depth of pleural effusion, and the location and morphology of the pulmonary lesions in the chest CT images of children patients from the two groups. All the experiments are done in the MATLAB. RESULTS The results showed that the proportions of reticular shadow, ground glass shadow, bronchial inflation phase, tube wall thickening, and vascular bundle thickening on the CT images of children patients from the MPP group were dramatically higher than those of the MP + SP group (P < 0.05). The maximum transverse diameter of enlarged lymph node in children patients from the MPP group was obviously larger than the diameter of the MP + SP group (P < 0.05). The number of children patients with pleural effusion was 22 in the MP + SP group, which was greatly higher than the MPP group (P < 0.05). CONCLUSION In conclusion, the chest CT images of children patients from the MPP group were mainly pulmonary interstitial changes. Furthermore, the alveolar inflammation could be observed on the CT images shown when children patients were combined with SP infection. The more obvious manifestations were that the flaky shadows appeared in the lungs, the pleural effusion became thicker, and the transverse diameters of enlarged lymph nodes were bigger.
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Affiliation(s)
- Jing Wang
- 1Department of Infectious Diseases, Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu 210008, China
| | - Chen Xia
- 1Department of Infectious Diseases, Children's Hospital of Nanjing Medical University, Nanjing, Jiangsu 210008, China
| | - Ashutosh Sharma
- 2Institute of Computer Technology and Information Security, Southern Federal University, Rostov-on-Don, Russia
| | - Gurjot Singh Gaba
- 3School of Electronics and Electrical Engineering, Lovely Professional University, Phagwara 144411, India
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Huang H, Zuzarte-Luis V, Fragoso G, Calvé A, Hoang TA, Oliero M, Chabot-Roy G, Mullins-Dansereau V, Lesage S, Santos MM. Acute invariant NKT cell activation triggers an immune response that drives prominent changes in iron homeostasis. Sci Rep 2020; 10:21026. [PMID: 33273556 PMCID: PMC7713400 DOI: 10.1038/s41598-020-78037-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 11/19/2020] [Indexed: 12/17/2022] Open
Abstract
Iron homeostasis is an essential biological process that ensures the tissue distribution of iron for various cellular processes. As the major producer of hepcidin, the liver is central to the regulation of iron metabolism. The liver is also home to many immune cells, which upon activation may greatly impact iron metabolism. Here, we focus on the role of invariant natural killer T (iNKT) cells, a subset of T lymphocytes that, in mice, is most abundant in the liver. Activation of iNKT cells with the prototypical glycosphingolipid antigen, α-galactosylceramide, resulted in immune cell proliferation and biphasic changes in iron metabolism. This involved an early phase characterized by hypoferremia, hepcidin induction and ferroportin suppression, and a second phase associated with strong suppression of hepcidin despite elevated levels of circulating and tissue iron. We further show that these changes in iron metabolism are fully dependent on iNKT cell activation. Finally, we demonstrate that the biphasic regulation of hepcidin is independent of NK and Kupffer cells, and is initially driven by the STAT3 inflammatory pathway, whereas the second phase is regulated by repression of the BMP/SMAD signaling pathway. These findings indicate that iNKT activation and the resulting cell proliferation influence iron homeostasis.
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Affiliation(s)
- Hua Huang
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.,Département de Médecine, Université de Montréal, Montréal, Québec, Canada
| | | | - Gabriela Fragoso
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada
| | - Annie Calvé
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada
| | - Tuan Anh Hoang
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.,Département de Médecine, Université de Montréal, Montréal, Québec, Canada.,Centre INRS-Institut Armand-Frappier, Institut National de La Recherche Scientifique, 531 Boulevard des Prairies, Laval, Québec, Canada
| | - Manon Oliero
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | | | - Victor Mullins-Dansereau
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada.,Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada
| | - Sylvie Lesage
- Département de Microbiologie, Infectiologie et Immunologie, Université de Montréal, Montréal, Québec, Canada.,Maisonneuve-Rosemont Hospital Research Centre (CRHMR), Montréal, Québec, Canada
| | - Manuela M Santos
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, Québec, Canada. .,Département de Médecine, Université de Montréal, Montréal, Québec, Canada. .,Nutrition and Microbiome Laboratory, CRCHUM-R10.426, 900 rue Saint-Denis, Montréal, Québec, H2X 0A9, Canada.
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12
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Altamura S, Marques O, Colucci S, Mertens C, Alikhanyan K, Muckenthaler MU. Regulation of iron homeostasis: Lessons from mouse models. Mol Aspects Med 2020; 75:100872. [DOI: 10.1016/j.mam.2020.100872] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 06/28/2020] [Accepted: 07/02/2020] [Indexed: 12/13/2022]
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13
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Xiao X, Alfaro-Magallanes VM, Babitt JL. Bone morphogenic proteins in iron homeostasis. Bone 2020; 138:115495. [PMID: 32585319 PMCID: PMC7453787 DOI: 10.1016/j.bone.2020.115495] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 06/12/2020] [Accepted: 06/15/2020] [Indexed: 02/07/2023]
Abstract
The bone morphogenetic protein (BMP)-SMAD signaling pathway plays a central role in regulating hepcidin, which is the master hormone governing systemic iron homeostasis. Hepcidin is produced by the liver and acts on the iron exporter ferroportin to control iron absorption from the diet and iron release from body stores, thereby providing adequate iron for red blood cell production, while limiting the toxic effects of excess iron. BMP6 and BMP2 ligands produced by liver endothelial cells bind to BMP receptors and the coreceptor hemojuvelin (HJV) on hepatocytes to activate SMAD1/5/8 signaling, which directly upregulates hepcidin transcription. Most major signals that influence hepcidin production, including iron, erythropoietic drive, and inflammation, intersect with the BMP-SMAD pathway to regulate hepcidin transcription. Mutation or inactivation of BMP ligands, BMP receptors, HJV, SMADs or other proteins that modulate the BMP-SMAD pathway result in hepcidin dysregulation, leading to iron-related disorders, such as hemochromatosis and iron refractory iron deficiency anemia. Pharmacologic modulators of the BMP-SMAD pathway have shown efficacy in pre-clinical models to regulate hepcidin expression and treat iron-related disorders. This review will discuss recent insights into the role of the BMP-SMAD pathway in regulating hepcidin to control systemic iron homeostasis.
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Affiliation(s)
- Xia Xiao
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Víctor M Alfaro-Magallanes
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; LFE Research Group, Department of Health and Human Performance, Faculty of Physical Activity and Sport Sciences, Universidad Politécnica de Madrid (UPM), Madrid, Spain
| | - Jodie L Babitt
- Division of Nephrology, Program in Membrane Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
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14
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Kim YJ, Kim KS, Lim D, Yang DJ, Park JI, Kim KW, Jeong JH, Choi HS, Kim DK. Epigallocatechin-3-Gallate (EGCG)-Inducible SMILE Inhibits STAT3-Mediated Hepcidin Gene Expression. Antioxidants (Basel) 2020; 9:antiox9060514. [PMID: 32545266 PMCID: PMC7346121 DOI: 10.3390/antiox9060514] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/27/2020] [Accepted: 06/09/2020] [Indexed: 02/07/2023] Open
Abstract
Hepatic peptide hormone hepcidin, a key regulator of iron metabolism, is induced by inflammatory cytokine interleukin-6 (IL-6) in the pathogenesis of anemia of inflammation or microbial infections. Small heterodimer partner-interacting leucine zipper protein (SMILE)/CREBZF is a transcriptional corepressor of nuclear receptors that control hepatic glucose and lipid metabolism. Here, we examined the role of SMILE in regulating iron metabolism by inflammatory signals. Overexpression of SMILE significantly decreased activation of the Janus kinase 2-signal transducer and activator of transcription 3 (STAT3)-mediated hepcidin production and secretion that is triggered by the IL-6 signal in human and mouse hepatocytes. Moreover, SMILE co-localized and physically interacted with STAT3 in the nucleus in the presence of IL-6, which significantly suppressed binding of STAT3 to the hepcidin gene promoter. Interestingly, epigallocatechin-3-gallate (EGCG), a major component of green tea, induced SMILE expression through forkhead box protein O1 (FoxO1), as demonstrated in FoxO1 knockout primary hepatocytes. In addition, EGCG inhibited IL-6-induced hepcidin expression, which was reversed by SMILE knockdown. Finally, EGCG significantly suppressed lipopolysaccharide-induced hepcidin secretion and hypoferremia through induction of SMILE expression in mice. These results reveal a previously unrecognized role of EGCG-inducible SMILE in the IL-6-dependent transcriptional regulation of iron metabolism.
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Affiliation(s)
- Yu-Ji Kim
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Korea;
| | - Ki-Sun Kim
- School of Biological Sciences and Technology, Chonnam National University, Gwangju 61186, Korea; (K.-S.K.); (H.-S.C.)
| | - Daejin Lim
- Department of Microbiology, Chonnam National University Medical School, Gwangju 61468, Korea; (D.L.); (J.-H.J.)
| | - Dong Ju Yang
- Department of Oral Biology, BK21 PLUS, Yonsei University College of Dentistry, Seoul, 03722, Korea; (D.J.Y.); (K.W.K.)
| | - Jae-Il Park
- Korea Basic Science Institute, Gwangju Center at Chonnam National University, Gwangju 61186, Korea;
| | - Ki Woo Kim
- Department of Oral Biology, BK21 PLUS, Yonsei University College of Dentistry, Seoul, 03722, Korea; (D.J.Y.); (K.W.K.)
| | - Jae-Ho Jeong
- Department of Microbiology, Chonnam National University Medical School, Gwangju 61468, Korea; (D.L.); (J.-H.J.)
| | - Hueng-Sik Choi
- School of Biological Sciences and Technology, Chonnam National University, Gwangju 61186, Korea; (K.-S.K.); (H.-S.C.)
| | - Don-Kyu Kim
- Department of Integrative Food, Bioscience and Biotechnology, Chonnam National University, Gwangju 61186, Korea;
- Correspondence: ; Tel.: +82-62-530-2166; Fax: +82-62-530-2160
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15
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Giudici F, Lombardelli L, Russo E, Cavalli T, Zambonin D, Logiodice F, Kullolli O, Giusti L, Bargellini T, Fazi M, Biancone L, Scaringi S, Clemente AM, Perissi E, Delfino G, Torcia MG, Ficari F, Tonelli F, Piccinni MP, Malentacchi C. Multiplex gene expression profile in inflamed mucosa of patients with Crohn’s disease ileal localization: A pilot study. World J Clin Cases 2019; 7:2463-2476. [PMID: 31559282 PMCID: PMC6745337 DOI: 10.12998/wjcc.v7.i17.2463] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 07/12/2019] [Accepted: 07/27/2019] [Indexed: 02/05/2023] Open
Abstract
BACKGROUND Crohn’s disease (CD) is a complex disorder resulting from the interaction of genetic, environmental, and microbial factors. The pathogenic process may potentially affect any segment of the gastrointestinal tract, but a selective location in the terminal ileum was reported in 50% of patients.
AIM To characterize clinical sub-phenotypes (colonic and/or ileal) within the same disease, in order to identify new therapeutic targets.
METHODS 14 consecutive patients undergoing surgery for ileal CD were recruited for this study. Peripheral blood samples from each patient were collected and the main polymorphisms of the gene Card15/Nod2 (R702W, G908R, and 1007fs) were analyzed in each sample. In addition, tissue samples were taken from both the tract affected by CD and from the apparently healthy and disease-free margins (internal controls). We used a multiplex gene assay in specimens obtained from patients with ileal localization of CD to evaluate the simultaneous expression of 24 genes involved in the pathogenesis of the disease. We also processed surgery gut samples with routine light microscopy (LM) and transmission electron microscopy (TEM) techniques to evaluate their structural and ultrastructural features.
RESULTS We found a significant increase of Th17 (IL17A and IL17F, IL 23R and CCR6) and Th1 (IFN-γ) gene expression in inflamed mucosa compared to non-inflamed sites of 14 CD patients. DEFB4 and HAMP, two genes coding for antimicrobial peptides, were also strongly activated in inflamed ileal mucosa, suggesting the overwhelming stimulation of epithelial cells by commensal microbiota. IFN-γ and CCR6 were more expressed in inflamed mucosa of CD patients with ileal localization compared with patients with colonic localization suggesting a more aggressive inflammation process in this site. Morphological analysis of the epithelial lining of Lieberkün crypts disclosed enhanced release activity from goblet mucocytes, whereas the lamina propria contained numerous cells pertaining to various lines.
CONCLUSION We observed that the expression of ileal genes related to Th1 and Th17 activity is strongly activated as well as the expression of genes involved in microbiota regulation.
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Affiliation(s)
- Francesco Giudici
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Letizia Lombardelli
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Edda Russo
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Tiziana Cavalli
- Dipartimento Chirurgico Ortopedico, Ospedale Carlo Poma di Mantova, Firenze 50134, Italy
| | - Daniela Zambonin
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Federica Logiodice
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Ornela Kullolli
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Lamberto Giusti
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Firenze, Firenze 50134, Italy
| | - Tatiana Bargellini
- Surgical Unit, Department of Surgery and Translational Medicine, University of Firenze, Firenze 50134, Italy
| | - Marilena Fazi
- Surgical Unit, Department of Surgery and Translational Medicine, University of Firenze, Firenze 50134, Italy
| | - Livia Biancone
- Department of Internal Medicine, University of Roma Tor Vergata, Roma 00133, Italy
| | - Stefano Scaringi
- Surgical Unit, Department of Surgery and Translational Medicine, University of Firenze, Firenze 50134, Italy
| | - Ann Maria Clemente
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Eloisa Perissi
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Giovanni Delfino
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Firenze, Firenze 50134, Italy
| | - Maria G Torcia
- Marie- Pierre Piccinni, Department of Experimental and Clinical Medicine, University of Firenze, Firenze 50134, Italy
| | - Ferdinando Ficari
- Surgical Unit, Department of Surgery and Translational Medicine, University of Firenze, Firenze 50134, Italy
| | - Francesco Tonelli
- Surgical Unit, Department of Surgery and Translational Medicine, University of Firenze, Firenze 50134, Italy
| | | | - Cecilia Malentacchi
- Department of Experimental and Clinical Biomedical Sciences “Mario Serio”, University of Firenze, Firenze 50134, Italy
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16
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Abstract
Hepcidin, the main regulator of iron metabolism, is synthesized and released by hepatocytes in response to increased body iron concentration and inflammation. Deregulation of hepcidin expression is a common feature of genetic and acquired iron disorders: in Hereditary Hemochromatosis (HH) and iron-loading anemias low hepcidin causes iron overload, while in Iron Refractory Iron Deficiency Anemia (IRIDA) and anemia of inflammation (AI), high hepcidin levels induce iron-restricted erythropoiesis. Hepcidin expression in the liver is mainly controlled by the BMP-SMAD pathway, activated in a paracrine manner by BMP2 and BMP6 produced by liver sinusoidal endothelial cells. The BMP type I receptors ALK2 and ALK3 are responsible for iron-dependent hepcidin upregulation and basal hepcidin expression, respectively. Characterization of animal models with genetic inactivation of the key components of the pathway has suggested the existence of two BMP/SMAD pathway branches: the first ALK3 and HH proteins dependent, responsive to BMP2 for basal hepcidin activation, and the second ALK2 dependent, activated by BMP6 in response to increased tissue iron. The erythroid inhibitor of hepcidin Erythroferrone also impacts on the liver BMP-SMAD pathway although its effect is blunted by pathway hyper-activation. The liver BMP-SMAD pathway is required also in inflammation to cooperate with JAK2/STAT3 signaling for full hepcidin activation. Pharmacologic targeting of BMP-SMAD pathway components or regulators may improve the outcome of both genetic and acquired disorders of iron overload and deficiency by increasing or inhibiting hepcidin expression.
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17
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Santos-Silva A, Ribeiro S, Reis F, Belo L. Hepcidin in chronic kidney disease anemia. VITAMINS AND HORMONES 2019; 110:243-264. [PMID: 30798815 DOI: 10.1016/bs.vh.2019.01.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Chronic kidney disease (CKD) is associated with several complications that worsen with progression of disease; anemia, disturbances in iron metabolism and inflammation are common features. Inflammatory response starts early, releasing pro-inflammatory cytokines, acute phase reactants and hepcidin. Hepcidin production is modulated by several factors, as hypoxia/anemia, erythropoietin and erythropoiesis products, transferrin saturation (TSAT) and liver iron levels, which are altered in CKD. Treatment of CKD anemia is based on pharmaceutical intervention, with erythropoietic stimulating agents and/or iron supplementation; however, in spite of the erythropoietic benefits, this therapy, on a regular basis, involves risks, namely iron overload. To overcome these risks, some therapeutic approaches are under study to target CKD anemia. Considering the actual alerts about risk of iron overload in dialysis patients, inhibition of hepcidin, the central key player in iron homeostasis, could be a pivotal strategy in the management of CKD anemia.
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Affiliation(s)
- Alice Santos-Silva
- UCIBIO\REQUIMTE, Laboratory of Biochemistry, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal.
| | - Sandra Ribeiro
- UCIBIO\REQUIMTE, Laboratory of Biochemistry, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
| | - Flávio Reis
- Institute of Pharmacology & Experimental Therapeutics, Coimbra Institute for Clinical and Biomedical Research (iCBR), Faculty of Medicine, CNC.IBILI Consortium & CIBB Consortium, University of Coimbra, Coimbra, Portugal
| | - Luís Belo
- UCIBIO\REQUIMTE, Laboratory of Biochemistry, Department of Biological Sciences, Faculty of Pharmacy, University of Porto, Porto, Portugal
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18
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Wu J, Yang L, Zhang X, Li Y, Wang J, Zhang S, Liu H, Huang H, Wang Y, Yuan L, Cheng X, Zhuang D, Zhang H, Chen X. MC-LR induces dysregulation of iron homeostasis by inhibiting hepcidin expression: A preliminary study. CHEMOSPHERE 2018; 212:572-584. [PMID: 30172039 DOI: 10.1016/j.chemosphere.2018.08.077] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 08/11/2018] [Accepted: 08/14/2018] [Indexed: 06/08/2023]
Abstract
The liver is an important iron storage site and a primary MC-LR target. C57BL/6 and Hfe-/- mice were used to investigate effects and mechanisms of MC-LR on systematic iron homeostasis. Body weight, tissue iron content, hematological and serological indexes, and histopathological were evaluated. Ultrastructure and iron metabolism-related genes and proteins were analyzed. MC-LR induced dose-dependent increases in red blood cells, hemoglobin, and hematocrit. In contrast MC-LR-induced dose-dependent decreases in mean corpuscular volume, hemoglobin, and hemoglobin concentration were observed both C57BL/6 and Hfe-/- mice. In both mouse species, serological indexes increased. Aggravated liver and spleen iron were observed in C57BL/6 mice, consistent with Perls' Prussian blue staining. However, an opposite trend was observed in Hfe-/- mice. C57BL/6 mice had lower Hamp1 (Hepcidn), Bmp6, Il-6, and Tmprss6. Significant increased Hjv, Hif-1α and Hif-2α were observed in both C57BL/6 and Hfe-/- mice. MC-LR-induced pathological lesions were dose-dependent increase in C57BL/6 mice. More severe pathological injuries in MC-LR groups (25 μg/kg) were observed in Hfe-/- mice than in C57BL/6 mice. In Hfe-/- mice, upon exposure to 25 μg/kg MC-LR, mitochondrial membranes were damaged and mitochondrial counts increased with significant swelling. These results indicated that MC-LR can induce the accumulation of iron in C57BL/6 mice with the occurrence of anemia, similar to thalassemia. Moreover, dysregulation of iron homeostasis may be due to MC-LR-induced Hamp1 downregulation, possibly mediated by hypoxia or the IL6-STAT3 and BMP-SMAD signaling pathways.
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Affiliation(s)
- Jinxia Wu
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Lei Yang
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China; School of Nursing, Xinxiang Medical University, Xinxiang, Henan, 453003, PR China
| | - Xiaofeng Zhang
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Yang Li
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Jianyao Wang
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Shenshen Zhang
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Haohao Liu
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Hui Huang
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Yueqin Wang
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Le Yuan
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Xuemin Cheng
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Donggang Zhuang
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China
| | - Huizhen Zhang
- College of Public Health, Zhengzhou University, Zhengzhou, Henan, 450001, PR China.
| | - Xinghai Chen
- Department of Chemistry and Biochemistry, St Mary's University, San Antonio, TX, USA
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19
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Samba-Mondonga M, Calvé A, Mallette FA, Santos MM. MyD88 Regulates the Expression of SMAD4 and the Iron Regulatory Hormone Hepcidin. Front Cell Dev Biol 2018; 6:105. [PMID: 30234111 PMCID: PMC6127602 DOI: 10.3389/fcell.2018.00105] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 08/14/2018] [Indexed: 12/26/2022] Open
Abstract
The myeloid differentiation primary response gene 88 (MyD88) is an adaptive protein that is essential for the induction of inflammatory cytokines through almost all the Toll-like receptors (TLRs). TLRs recognize molecular patterns present in microorganisms called pathogen-associated molecular patterns. Therefore, MyD88 plays an important role in innate immunity since its activation triggers the first line of defense against microorganisms. Herein, we describe the first reported role of MyD88 in an interconnection between innate immunity and the iron-sensing pathway (BMP/SMAD4). We found that direct interaction of MyD88 with SMAD4 protein activated hepcidin expression. The iron regulatory hormone hepcidin is indispensable for the intestinal regulation of iron absorption and iron recycling by macrophages. We show that MyD88 induces hepcidin expression in a manner dependent on the proximal BMP responsive element on the hepcidin gene (HAMP) promoter. We identified the Toll/interleukin-1 receptor (TIR) domain of MyD88 as the domain of interaction with SMAD4. Furthermore, we show that BMP6 stimulation, which activates SMAD6 expression, also induces MyD88 proteosomal degradation as a negative feedback mechanism to limit hepcidin induction. Finally, we report that the MyD88 gain-of-function L265P mutation, frequently encountered in B-cell lymphomas such as Waldenström’s macroglobulinemia, enhances hepcidin expression and iron accumulation in B cell lines. Our results reveal a new potential role for MyD88 in the SMAD signaling pathway and iron homeostasis regulation.
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Affiliation(s)
- Macha Samba-Mondonga
- Nutrition and Microbiome Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Annie Calvé
- Nutrition and Microbiome Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada
| | - Frédérick A Mallette
- Département de Médecine, Université de Montréal, Montréal, QC, Canada.,Centre de Recherche de l'Hôpital Maisonneuve-Rosemont, Université de Montréal, Montréal, QC, Canada
| | - Manuela M Santos
- Nutrition and Microbiome Laboratory, Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada
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20
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An P, Wang H, Wu Q, Wang J, Xia Z, He X, Wang X, Chen Y, Min J, Wang F. Smad7 deficiency decreases iron and haemoglobin through hepcidin up-regulation by multilayer compensatory mechanisms. J Cell Mol Med 2018; 22:3035-3044. [PMID: 29575577 PMCID: PMC5980186 DOI: 10.1111/jcmm.13546] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Accepted: 01/02/2018] [Indexed: 01/06/2023] Open
Abstract
To maintain iron homoeostasis, the iron regulatory hormone hepcidin is tightly controlled by BMP-Smad signalling pathway, but the physiological role of Smad7 in hepcidin regulation remains elusive. We generated and characterized hepatocyte-specific Smad7 knockout mice (Smad7Alb/Alb ), which showed decreased serum iron, tissue iron, haemoglobin concentration, up-regulated hepcidin and increased phosphor-Smad1/5/8 levels in both isolated primary hepatocytes and liver tissues. Increased levels of hepcidin lead to reduced expression of intestinal ferroportin and mild iron deficiency anaemia. Interestingly, we found no difference in hepcidin expression or phosphor-Smad1/5/8 levels between iron-challenged Smad7Alb/Alb and Smad7flox/flox , suggesting other factors assume the role of iron-induced hepcidin regulation in Smad7 deletion. We performed RNA-seq to identify differentially expressed genes in the liver. Significantly up-regulated genes were then mapped to pathways, revealing TGF-β signalling as one of the most relevant pathways, including the up-regulated genes Smad6, Bambi and Fst (Follistatin). We found that Smad6 and Bambi-but not Follistatin-are controlled by the iron-BMP-Smad pathway. Overexpressing Smad6, Bambi or Follistatin in cells significantly reduced hepcidin expression. Smad7 functions as a key regulator of iron homoeostasis by negatively controlling hepcidin expression, and Smad6 and Smad7 have non-redundant roles. Smad6, Bambi and Follistatin serve as additional inhibitors of hepcidin in the liver.
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Affiliation(s)
- Peng An
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Hao Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China.,Precision Nutrition Innovation Center, School of Public Health, Zhengzhou University, Zhengzhou, China
| | - Qian Wu
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Jiaming Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Zhidan Xia
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xuyan He
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xinhui Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yan Chen
- Key Laboratory of Nutrition and Metabolism, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai, China
| | - Junxia Min
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China
| | - Fudi Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, China Agricultural University, Beijing, China.,School of Public Health, The First Affiliated Hospital, Institute of Translational Medicine, Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, School of Medicine, Zhejiang University, Hangzhou, China.,Precision Nutrition Innovation Center, School of Public Health, Zhengzhou University, Zhengzhou, China
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21
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Hepatic Smad7 overexpression causes severe iron overload in mice. Blood 2017; 131:581-585. [PMID: 29237592 DOI: 10.1182/blood-2017-07-796797] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 12/02/2017] [Indexed: 02/07/2023] Open
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22
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McLachlan S, Page KE, Lee SM, Loguinov A, Valore E, Hui ST, Jung G, Zhou J, Lusis AJ, Fuqua B, Ganz T, Nemeth E, Vulpe CD. Hamp1 mRNA and plasma hepcidin levels are influenced by sex and strain but do not predict tissue iron levels in inbred mice. Am J Physiol Gastrointest Liver Physiol 2017; 313:G511-G523. [PMID: 28798083 PMCID: PMC5792216 DOI: 10.1152/ajpgi.00307.2016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Revised: 07/17/2017] [Accepted: 07/24/2017] [Indexed: 01/31/2023]
Abstract
Iron homeostasis is tightly regulated, and the peptide hormone hepcidin is considered to be a principal regulator of iron metabolism. Previous studies in a limited number of mouse strains found equivocal sex- and strain-dependent differences in mRNA and serum levels of hepcidin and reported conflicting data on the relationship between hepcidin (Hamp1) mRNA levels and iron status. Our aim was to clarify the relationships between strain, sex, and hepcidin expression by examining multiple tissues and the effects of different dietary conditions in multiple inbred strains. Two studies were done: first, Hamp1 mRNA, liver iron, and plasma diferric transferrin levels were measured in 14 inbred strains on a control diet; and second, Hamp1 mRNA and plasma hepcidin levels in both sexes and iron levels in the heart, kidneys, liver, pancreas, and spleen in males were measured in nine inbred/recombinant inbred strains raised on an iron-sufficient or high-iron diet. Both sex and strain have a significant effect on both hepcidin mRNA (primarily a sex effect) and plasma hepcidin levels (primarily a strain effect). However, liver iron and diferric transferrin levels are not predictors of Hamp1 mRNA levels in mice fed iron-sufficient or high-iron diets, nor are the Hamp1 mRNA and plasma hepcidin levels good predictors of tissue iron levels, at least in males. We also measured plasma erythroferrone, performed RNA-sequencing analysis of liver samples from six inbred strains fed the iron-sufficient, low-iron, or high-iron diets, and explored differences in gene expression between the strains with the highest and lowest hepcidin levels.NEW & NOTEWORTHY Both sex and strain have a significant effect on both hepcidin mRNA (primarily a sex effect) and plasma hepcidin levels (primarily a strain effect). Liver iron and diferric transferrin levels are not predictors of Hamp1 mRNA levels in mice, nor are the Hamp1 mRNA and plasma hepcidin levels good predictors of tissue iron levels, at least in males.
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Affiliation(s)
- Stela McLachlan
- Centre for Population Health Sciences, Usher Institute of Population Health Sciences and Informatics, University of Edinburgh, Edinburgh, United Kingdom;
| | - Kathryn E. Page
- 2Department of Nutritional Science & Toxicology, University of California, Berkeley, California;
| | - Seung-Min Lee
- 3Department of Food and Nutrition, College of Human Ecology, Yonsei University, Seoul, Korea;
| | - Alex Loguinov
- 5Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Erika Valore
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Simon T. Hui
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Grace Jung
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Jie Zhou
- 5Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
| | - Aldons J. Lusis
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Brie Fuqua
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Tomas Ganz
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Elizabeta Nemeth
- 4Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California; and
| | - Chris D. Vulpe
- 2Department of Nutritional Science & Toxicology, University of California, Berkeley, California; ,5Department of Physiological Sciences, College of Veterinary Medicine, University of Florida, Gainesville, Florida
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Zehra A, Saleh Abdullah SM, Saboor M, Moinuddin. Effect of Intravenous Iron Supplementation on Hepcidin Levels in Iron Deficient Pregnant Females in Second and Third Trimester. Indian J Hematol Blood Transfus 2017; 33:396-401. [PMID: 28824243 PMCID: PMC5544634 DOI: 10.1007/s12288-016-0736-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 10/07/2016] [Indexed: 10/20/2022] Open
Abstract
Objective of the study was to assess effect of iron therapy on serum hepcidin levels in iron deficient pregnant women and its correlation with hemoglobin, serum iron profile and C-reactive protein (CRP). A total of 100 pregnant women were enrolled in the study; 25 were included in the "control group" having normal hematological and biochemical parameters while 75 iron deficient pregnant women were enrolled in the "patient group" with low hematological and biochemical parameters. CRP was done to rule out inflammation and to observe its association with hepcidin. Intravenous iron was administered to the patient group. Post treatment CBC, serum iron, serum ferritin and serum hepcidin were determined. Difference between pre and post treatment hemoglobin, serum iron, serum ferritin and serum hepcidin levels were determined and correlation among them was calculated. Post treatment serum hepcidin levels were significantly higher than pretreatment level (p = 0.001). However, no correlation was seen between serum hepcidin, serum iron, serum ferritin and hemoglobin. Hepcidin levels remain low during pregnancy as there is increased demand for iron in pregnancy. Iron supplementation results in increased hepcidin levels; however no mathematical correlation was found between serum hepcidin level and serum iron profile.
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Affiliation(s)
- Amtuz Zehra
- Department of Pathology, Baqai Medical University, Karachi, Pakistan
| | | | - Muhammad Saboor
- Department of Medical Laboratory Technology, College of Applied Medical Sciences, Jazan University, Jazan, Saudi Arabia
| | - Moinuddin
- Baqai Institute of Hematology, Baqai Medical University, Karachi, Pakistan
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24
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Muckenthaler MU, Rivella S, Hentze MW, Galy B. A Red Carpet for Iron Metabolism. Cell 2017; 168:344-361. [PMID: 28129536 DOI: 10.1016/j.cell.2016.12.034] [Citation(s) in RCA: 760] [Impact Index Per Article: 108.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Revised: 10/17/2016] [Accepted: 12/21/2016] [Indexed: 02/06/2023]
Abstract
200 billion red blood cells (RBCs) are produced every day, requiring more than 2 × 1015 iron atoms every second to maintain adequate erythropoiesis. These numbers translate into 20 mL of blood being produced each day, containing 6 g of hemoglobin and 20 mg of iron. These impressive numbers illustrate why the making and breaking of RBCs is at the heart of iron physiology, providing an ideal context to discuss recent progress in understanding the systemic and cellular mechanisms that underlie the regulation of iron homeostasis and its disorders.
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Affiliation(s)
- Martina U Muckenthaler
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and University of Heidelberg, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany; Department of Pediatric Oncology, Hematology and Immunology, Im Neuenheimer Feld 153, 69120 Heidelberg, Germany
| | - Stefano Rivella
- Children's Hospital of Philadelphia, 3615 Civic Center Blvd, Philadelphia, PA 19104, USA
| | - Matthias W Hentze
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory and University of Heidelberg, Im Neuenheimer Feld 350, 69120 Heidelberg, Germany; European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.
| | - Bruno Galy
- Division of Virus-Associated Carcinogenesis (F170), German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120 Heidelberg, Germany
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25
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Reichert CO, da Cunha J, Levy D, Maselli LMF, Bydlowski SP, Spada C. Hepcidin: Homeostasis and Diseases Related to Iron Metabolism. Acta Haematol 2017; 137:220-236. [PMID: 28514781 DOI: 10.1159/000471838] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 03/20/2017] [Indexed: 12/14/2022]
Abstract
Iron is an essential metal for cell survival that is regulated by the peptide hormone hepcidin. However, its influence on certain diseases is directly related to iron metabolism or secondary to underlying diseases. Genetic alterations influence the serum hepcidin concentration, which can lead to an iron overload in tissues, as observed in haemochromatosis, in which serum hepcidin or defective hepcidin synthesis is observed. Another genetic imbalance of iron is iron-refractory anaemia, in which serum concentrations of hepcidin are increased, precluding the flow and efflux of extra- and intracellular iron. During the pathogenesis of certain diseases, the resulting oxidative stress, as well as the increase in inflammatory cytokines, influences the transcription of the HAMP gene to generate a secondary anaemia due to the increase in the serum concentration of hepcidin. To date, there is no available drug to inhibit or enhance hepcidin transcription, mostly due to the cytotoxicity described in the in vitro models. The proposed therapeutic targets are still in the early stages of clinical trials. Some candidates are promising, such as heparin derivatives and minihepcidins. This review describes the main pathways of systemic and genetic regulation of hepcidin, as well as its influence on the disorders related to iron metabolism.
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Affiliation(s)
- Cadiele Oliana Reichert
- Clinical Analysis Department, Health Sciences Center, Federal University of Santa Catarina (UFSC), Florianópolis, Brazil
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26
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Mleczko-Sanecka K, da Silva AR, Call D, Neves J, Schmeer N, Damm G, Seehofer D, Muckenthaler MU. Imatinib and spironolactone suppress hepcidin expression. Haematologica 2017; 102:1173-1184. [PMID: 28385785 PMCID: PMC5566021 DOI: 10.3324/haematol.2016.162917] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Accepted: 04/05/2017] [Indexed: 12/21/2022] Open
Abstract
Disorders of iron metabolism are largely attributed to an excessive or insufficient expression of hepcidin, the master regulator of systemic iron homeostasis. Here, we investigated whether drugs targeting genetic regulators of hepcidin can affect iron homeostasis. We focused our efforts on drugs approved for clinical use to enable repositioning strategies and/or to reveal iron-related side effects of widely prescribed therapeutics. To identify hepcidin-modulating therapeutics, we re-evaluated data generated by a genome-wide RNAi screen for hepcidin regulators. We identified ‘druggable’ screening hits and validated those by applying RNAi of potential drug targets and small-molecule testing in a hepatocytic cell line, in primary murine and human hepatocytes and in mice. We initially identified spironolactone, diclofenac, imatinib and Suberoylanilide hydroxamic acid (SAHA) as hepcidin modulating drugs in cellular assays. Among these, imatinib and spironolactone further suppressed liver hepcidin expression in mice. Our results demonstrate that a commonly used anti-hypertensive drug, spironolactone, which is prescribed for the treatment of heart failure, acne and female hirsutism, as well as imatinib, a first-line, lifelong therapeutic option for some frequent cancer types suppress hepcidin expression in cultured cells and in mice. We expect these results to be of relevance for patient management, which needs to be addressed in prospective clinical studies.
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Affiliation(s)
- Katarzyna Mleczko-Sanecka
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg and Molecular Medicine Partnership Unit, Heidelberg, Germany .,International Institute of Molecular and Cell Biology, Warsaw, Poland
| | - Ana Rita da Silva
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg and Molecular Medicine Partnership Unit, Heidelberg, Germany
| | - Debora Call
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg and Molecular Medicine Partnership Unit, Heidelberg, Germany
| | - Joana Neves
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg and Molecular Medicine Partnership Unit, Heidelberg, Germany
| | - Nikolai Schmeer
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg and Molecular Medicine Partnership Unit, Heidelberg, Germany
| | - Georg Damm
- Department of Hepatobiliary Surgery and Visceral Transplantation, University of Berlin, Germany.,Department of Hepatobiliary Surgery and Visceral Transplantation, University of Leipzig, Germany
| | - Daniel Seehofer
- Department of Hepatobiliary Surgery and Visceral Transplantation, University of Berlin, Germany.,Department of Hepatobiliary Surgery and Visceral Transplantation, University of Leipzig, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg and Molecular Medicine Partnership Unit, Heidelberg, Germany
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27
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Enculescu M, Metzendorf C, Sparla R, Hahnel M, Bode J, Muckenthaler MU, Legewie S. Modelling Systemic Iron Regulation during Dietary Iron Overload and Acute Inflammation: Role of Hepcidin-Independent Mechanisms. PLoS Comput Biol 2017; 13:e1005322. [PMID: 28068331 PMCID: PMC5261815 DOI: 10.1371/journal.pcbi.1005322] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Revised: 01/24/2017] [Accepted: 12/19/2016] [Indexed: 01/01/2023] Open
Abstract
Systemic iron levels must be maintained in physiological concentrations to prevent diseases associated with iron deficiency or iron overload. A key role in this process plays ferroportin, the only known mammalian transmembrane iron exporter, which releases iron from duodenal enterocytes, hepatocytes, or iron-recycling macrophages into the blood stream. Ferroportin expression is tightly controlled by transcriptional and post-transcriptional mechanisms in response to hypoxia, iron deficiency, heme iron and inflammatory cues by cell-autonomous and systemic mechanisms. At the systemic level, the iron-regulatory hormone hepcidin is released from the liver in response to these cues, binds to ferroportin and triggers its degradation. The relative importance of individual ferroportin control mechanisms and their interplay at the systemic level is incompletely understood. Here, we built a mathematical model of systemic iron regulation. It incorporates the dynamics of organ iron pools as well as regulation by the hepcidin/ferroportin system. We calibrated and validated the model with time-resolved measurements of iron responses in mice challenged with dietary iron overload and/or inflammation. The model demonstrates that inflammation mainly reduces the amount of iron in the blood stream by reducing intracellular ferroportin transcription, and not by hepcidin-dependent ferroportin protein destabilization. In contrast, ferroportin regulation by hepcidin is the predominant mechanism of iron homeostasis in response to changing iron diets for a big range of dietary iron contents. The model further reveals that additional homeostasis mechanisms must be taken into account at very high dietary iron levels, including the saturation of intestinal uptake of nutritional iron and the uptake of circulating, non-transferrin-bound iron, into liver. Taken together, our model quantitatively describes systemic iron metabolism and generated experimentally testable predictions for additional ferroportin-independent homeostasis mechanisms. The importance of iron in many physiological processes relies on its ability to participate in reduction-oxidation reactions. This property also leads to potential toxicity if concentrations of free iron are not properly managed by cells and tissues. Multicellular organisms therefore evolved intricate regulatory mechanisms to control systemic iron levels. A central regulatory mechanism is the binding of the hormone hepcidin to the iron exporter ferroportin, which controls the major fluxes of iron into blood plasma. Here, we present a mathematical model that is fitted and validated against experimental data to simulate the iron content in different organs following dietary changes and/or inflammatory states, or genetic perturbation of the hepcidin/ferroportin regulatory system. We find that hepcidin mediated ferroportin control is essential, but not sufficient to quantitatively explain several of our experimental findings. Thus, further regulatory mechanisms had to be included in the model to reproduce reduced serum iron levels in response to inflammation, the preferential accumulation of iron in the liver in the case of iron overload, or the maintenance of physiological serum iron concentrations if dietary iron levels are very high. We conclude that hepcidin-independent mechanisms play an important role in maintaining systemic iron homeostasis.
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Affiliation(s)
| | - Christoph Metzendorf
- Pediatric Oncology, Hematology & Immunology, University Hospital Heidelberg, Heidelberg, Germany.,Molecular Medicine Partnership Unit, Heidelberg University, Heidelberg, Germany
| | - Richard Sparla
- Molecular Medicine Partnership Unit, Heidelberg University, Heidelberg, Germany
| | - Maximilian Hahnel
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Johannes Bode
- Department of Gastroenterology, Hepatology and Infectious Diseases, Medical Faculty, University Hospital, Heinrich-Heine-University Düsseldorf, Düsseldorf, Germany
| | - Martina U Muckenthaler
- Pediatric Oncology, Hematology & Immunology, University Hospital Heidelberg, Heidelberg, Germany.,Molecular Medicine Partnership Unit, Heidelberg University, Heidelberg, Germany
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28
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Kim DK, Kim YH, Jung YS, Kim KS, Jeong JH, Lee YS, Yuk JM, Oh BC, Choy HE, Dooley S, Muckenthaler MU, Lee CH, Choi HS. Orphan nuclear receptor SHP regulates iron metabolism through inhibition of BMP6-mediated hepcidin expression. Sci Rep 2016; 6:34630. [PMID: 27688041 PMCID: PMC5043349 DOI: 10.1038/srep34630] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/12/2016] [Indexed: 02/08/2023] Open
Abstract
Small heterodimer partner (SHP) is a transcriptional corepressor regulating diverse metabolic processes. Here, we show that SHP acts as an intrinsic negative regulator of iron homeostasis. SHP-deficient mice maintained on a high-iron diet showed increased serum hepcidin levels, decreased expression of the iron exporter ferroportin as well as iron accumulation compared to WT mice. Conversely, overexpression of either SHP or AMP-activated protein kinase (AMPK), a metabolic sensor inducing SHP expression, suppressed BMP6-induced hepcidin expression. In addition, an inhibitory effect of AMPK activators metformin and AICAR on BMP6-mediated hepcidin gene expression was significantly attenuated by ablation of SHP expression. Interestingly, SHP physically interacted with SMAD1 and suppressed BMP6-mediated recruitment of the SMAD complex to the hepcidin gene promoter by inhibiting the formation of SMAD1 and SMAD4 complex. Finally, overexpression of SHP and metformin treatment of BMP6 stimulated mice substantially restored hepcidin expression and serum iron to baseline levels. These results reveal a previously unrecognized role for SHP in the transcriptional control of iron homeostasis.
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Affiliation(s)
- Don-Kyu Kim
- National Creative Research Initiatives Center for Nuclear Receptor Signals and Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea
| | - Yong-Hoon Kim
- Korea Research Institute of Bioscience and Biotechnology, University of Science and Technology (UST), Yuseong-gu, Daejeon, Republic of Korea
| | - Yoon Seok Jung
- National Creative Research Initiatives Center for Nuclear Receptor Signals and Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea
| | - Ki-Sun Kim
- National Creative Research Initiatives Center for Nuclear Receptor Signals and Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea
| | - Jae-Ho Jeong
- Department of Microbiology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Yong-Soo Lee
- National Creative Research Initiatives Center for Nuclear Receptor Signals and Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea
| | - Jae-Min Yuk
- Department of Medical Science and Infection Biology, Chungnam National University School of Medicine, Daegeon, Republic of Korea
| | - Byung-Chul Oh
- Lee Gil Ya Cancer and Diabetes Institute, Gachon University Graduate School of Medicine, Incheon, Republic of Korea
| | - Hyon E Choy
- Department of Microbiology, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Steven Dooley
- Department of Medicine II, Section Molecular Hepatology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Martina U Muckenthaler
- Department of Pediatric Oncology, Hematology and Immunology, University of Heidelberg, Heidelberg, Germany.,Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany
| | - Chul-Ho Lee
- Korea Research Institute of Bioscience and Biotechnology, University of Science and Technology (UST), Yuseong-gu, Daejeon, Republic of Korea
| | - Hueng-Sik Choi
- National Creative Research Initiatives Center for Nuclear Receptor Signals and Hormone Research Center, School of Biological Sciences and Technology, Chonnam National University, Gwangju, Republic of Korea
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29
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Mendes JFR, Siqueira EMDA, de Brito E Silva JGM, Arruda SF. Vitamin A deficiency modulates iron metabolism independent of hemojuvelin (Hfe2) and bone morphogenetic protein 6 (Bmp6) transcript levels. GENES AND NUTRITION 2016; 11:1. [PMID: 27551308 PMCID: PMC4968453 DOI: 10.1186/s12263-016-0519-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 01/18/2016] [Indexed: 11/10/2022]
Abstract
BACKGROUND Considering that vitamin A deficiency modulates hepcidin expression and consequently affects iron metabolism, we evaluated the effect of vitamin A deficiency in the expression of genes involved in the hemojuvelin (HJV)-bone morphogenetic protein 6 (BMP6)-small mothers against decapentaplegic protein (SMAD) signaling pathway. METHODS Male Wistar rats were treated: control AIN-93G diet (CT), vitamin A-deficient diet (VAD), iron-deficient diet (FeD), vitamin A- and iron-deficient diet (VAFeD), or 12 mg all-trans retinoic acid (atRA)/kg diet. RESULTS Vitamin A deficiency (VAD) increased hepatic Bmp6 and Hfe2 mRNA levels and down-regulated hepatic Hamp, Smad7, Rarα, and intestinal Fpn1 mRNA levels compared with the control. The FeD rats showed lower hepatic Hamp, Bmp6, and Smad7 mRNA levels compared with those of the control, while in the VAFeD rats only Hamp and Smad7 mRNA levels were lower than those of the control. The VAFeD diet up-regulated intestinal Dmt1 mRNA levels in relation to those of the control. The replacement of retinyl ester by atRA did not restore hepatic Hamp mRNA levels; however, the hepatic Hfe2, Bmp6, and Smad7 mRNA levels were similar to the control. The atRA rats showed an increase of hepatic Rarα mRNA levels and a reduction of intestinal Dmt1 mRNA and Fpn1 levels compared with those of the control. CONCLUSIONS The HJV-BMP6-SMAD signaling pathway that normally activates the expression of hepcidin in iron deficiency is impaired by vitamin A deficiency despite increased expression of liver Bmp6 and Hfe2 mRNA levels and decreased expression of Smad7 mRNA. This response may be associated to the systemic iron deficiency and spleen iron retention promoted by vitamin A deficiency.
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Affiliation(s)
- Juliana Frossard Ribeiro Mendes
- Postgraduate Program in Human Nutrition, Faculty of Health Sciences, University of Brasília, Campus Universitário Darcy Ribeiro, POBox 70910-900, Brasília, DF Brazil ; Instituto de Ciências Biológicas, Departamento de Biologia Celular, Laboratório de Bioquímica da Nutrição, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Bloco J, 1 Andar. Asa Norte, Brasília, Distrito Federal CEP: 70910-900 Brasil
| | - Egle Machado de Almeida Siqueira
- Cell Biology Department of Biological Sciences Institute, University of Brasília, Campus Universitário Darcy Ribeiro, POBox 70910-900, Brasília, DF Brazil
| | | | - Sandra Fernandes Arruda
- Postgraduate Program in Human Nutrition, Faculty of Health Sciences, University of Brasília, Campus Universitário Darcy Ribeiro, POBox 70910-900, Brasília, DF Brazil ; Instituto de Ciências Biológicas, Departamento de Biologia Celular, Laboratório de Bioquímica da Nutrição, Universidade de Brasília, Campus Universitário Darcy Ribeiro, Bloco J, 1 Andar. Asa Norte, Brasília, Distrito Federal CEP: 70910-900 Brasil
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30
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Chen H, Choesang T, Li H, Sun S, Pham P, Bao W, Feola M, Westerman M, Li G, Follenzi A, Blanc L, Rivella S, Fleming RE, Ginzburg YZ. Increased hepcidin in transferrin-treated thalassemic mice correlates with increased liver BMP2 expression and decreased hepatocyte ERK activation. Haematologica 2015; 101:297-308. [PMID: 26635037 DOI: 10.3324/haematol.2015.127902] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 12/01/2015] [Indexed: 12/13/2022] Open
Abstract
Iron overload results in significant morbidity and mortality in β-thalassemic patients. Insufficient hepcidin is implicated in parenchymal iron overload in β-thalassemia and approaches to increase hepcidin have therapeutic potential. We have previously shown that exogenous apo-transferrin markedly ameliorates ineffective erythropoiesis and increases hepcidin expression in Hbb(th1/th1) (thalassemic) mice. We utilize in vivo and in vitro systems to investigate effects of exogenous apo-transferrin on Smad and ERK1/2 signaling, pathways that participate in hepcidin regulation. Our results demonstrate that apo-transferrin increases hepcidin expression in vivo despite decreased circulating and parenchymal iron concentrations and unchanged liver Bmp6 mRNA expression in thalassemic mice. Hepatocytes from apo-transferrin-treated mice demonstrate decreased ERK1/2 pathway and increased serum BMP2 concentration and hepatocyte BMP2 expression. Furthermore, hepatocyte ERK1/2 phosphorylation is enhanced by neutralizing anti-BMP2/4 antibodies and suppressed in vitro in a dose-dependent manner by BMP2, resulting in converse effects on hepcidin expression, and hepatocytes treated with MEK/ERK1/2 inhibitor U0126 in combination with BMP2 exhibit an additive increase in hepcidin expression. Lastly, bone marrow erythroferrone expression is normalized in apo-transferrin treated thalassemic mice but increased in apo-transferrin injected wild-type mice. These findings suggest that increased hepcidin expression after exogenous apo-transferrin is in part independent of erythroferrone and support a model in which apo-transferrin treatment in thalassemic mice increases BMP2 expression in the liver and other organs, decreases hepatocellular ERK1/2 activation, and increases nuclear Smad to increase hepcidin expression in hepatocytes.
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Affiliation(s)
- Huiyong Chen
- Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA
| | - Tenzin Choesang
- Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA
| | - Huihui Li
- Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA Central South University, Changsha, PR China
| | - Shuming Sun
- Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA
| | - Petra Pham
- Flow Cytometry Core Laboratory, LFKRI, New York Blood Center, NY, USA
| | - Weili Bao
- Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA
| | - Maria Feola
- Erythropoiesis Laboratory, LFKRI, New York Blood Center, NY, USA University of Piemonte Orientale, Amedeo Avogadro, Novara, Italy
| | | | - Guiyuan Li
- Central South University, Changsha, PR China
| | - Antonia Follenzi
- University of Piemonte Orientale, Amedeo Avogadro, Novara, Italy
| | - Lionel Blanc
- The Feinstein Institute for Medical Research, Manhasset, NY, USA
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31
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Kortas J, Prusik K, Flis D, Prusik K, Ziemann E, Leaver N, Antosiewicz J. Effect of Nordic Walking training on iron metabolism in elderly women. Clin Interv Aging 2015; 10:1889-96. [PMID: 26664101 PMCID: PMC4669095 DOI: 10.2147/cia.s90413] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND Despite several, well-documented pro-healthy effects of regular physical training, its influence on body iron stores in elderly people remains unknown. At the same time, body iron accumulation is associated with high risk of different morbidities. PURPOSE We hypothesized that Nordic Walking training would result in pro-healthy changes in an elderly group of subjects by reducing body iron stores via shifts in iron metabolism-regulating proteins. METHODS Thirty-seven women aged 67.7±5.3 years participated in this study. They underwent 32 weeks of training, 1-hour sessions three times a week, between October 2012 and May 2013. Fitness level, blood morphology, CRP, vitamin D, ferritin, hepcidin, and soluble Hjv were assessed before and after the training. RESULTS The training program caused a significant decrease in ferritin, which serves as a good marker of body iron stores. Simultaneously, the physical cardiorespiratory fitness had improved. Furthermore, blood hepcidin was positively correlated with the ferritin concentration after the training. The concentration of blood CRP dropped, but the change was nonsignificant. The applied training resulted in a blood Hjv increase, which was inversely correlated with the vitamin D concentration. CONCLUSION Overall the Nordic Walking training applied in elderly people significantly reduced blood ferritin concentration, which explains the observed decrease in body iron stores.
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Affiliation(s)
- Jakub Kortas
- Department of Recreation and Tourism, Gdansk University of Physical Education and Sport, Gdansk, Poland
| | - Katarzyna Prusik
- Department of Biomedical Basis of Health, Gdansk University of Physical Education and Sport, Gdansk, Poland
| | - Damian Flis
- Department of Bioenergetics and Physiology of Exercise, Medical University of Gdansk, Gdansk, Poland
| | - Krzysztof Prusik
- Department of Recreation and Tourism, Gdansk University of Physical Education and Sport, Gdansk, Poland
| | - Ewa Ziemann
- Department of Physiology and Pharmacology, Gdansk University of Physical Education and Sport, Gdansk, Poland
| | - Neil Leaver
- The Immunosuppression monitoring service (IMS) Laboratory, Royal Brompton & Harefield NHS Foundation Trust, Heart Science Centre, Harefield Hospital, Harefield, UK
| | - Jedrzej Antosiewicz
- Department of Biochemistry, Gdansk University of Physical Education and Sport, Gdansk, Poland
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Pietrangelo A. Genetics, Genetic Testing, and Management of Hemochromatosis: 15 Years Since Hepcidin. Gastroenterology 2015; 149:1240-1251.e4. [PMID: 26164493 DOI: 10.1053/j.gastro.2015.06.045] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 06/19/2015] [Accepted: 06/30/2015] [Indexed: 12/13/2022]
Abstract
The discovery of hepcidin in 2000 and the subsequent unprecedented explosion of research and discoveries in the iron field have dramatically changed our understanding of human disorders of iron metabolism. Today, hereditary hemochromatosis, the paradigmatic iron-loading disorder, is recognized as an endocrine disease due to the genetic loss of hepcidin, the iron hormone produced by the liver. This syndrome is due to unchecked transfer of iron into the bloodstream in the absence of increased erythropoietic needs and its toxic effects in parenchymatous organs. It is caused by mutations that affect any of the proteins that help hepcidin to monitor serum iron, including HFE and, in rarer instances, transferrin-receptor 2 and hemojuvelin, or make its receptor ferroportin, resistant to the hormone. In Caucasians, C282Y HFE homozygotes are numerous, but they are only predisposed to hemochromatosis; complete organ disease develops in a minority, due to alcohol abuse or concurrent genetic modifiers that are now being identified. HFE gene testing can be used to diagnose hemochromatosis in symptomatic patients, but analyses of liver histology and full gene sequencing are required to identify patients with rare, non-HFE forms of the disease. Due to the central pathogenic role of hepcidin, it is anticipated that nongenetic causes of hepcidin loss (eg, end-stage liver disease) can cause acquired forms of hemochromatosis. The mainstay of hemochromatosis management is still removal of iron by phlebotomy, first introduced in 1950s, but identification of hepcidin has not only shed new light on the pathogenesis of the disease and the approach to diagnosis, but etiologic therapeutic applications from these advances are now foreseen.
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Affiliation(s)
- Antonello Pietrangelo
- Unit of Internal Medicine 2 and Centre for Hemochromatosis, University Hospital of Modena, Modena, Italy.
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Drasdo D, Bode J, Dahmen U, Dirsch O, Dooley S, Gebhardt R, Ghallab A, Godoy P, Häussinger D, Hammad S, Hoehme S, Holzhütter HG, Klingmüller U, Kuepfer L, Timmer J, Zerial M, Hengstler JG. The virtual liver: state of the art and future perspectives. Arch Toxicol 2015; 88:2071-5. [PMID: 25331938 DOI: 10.1007/s00204-014-1384-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Dirk Drasdo
- Institut National de Recherche en Informatique et en Automatique (INRIA), Domaine de Voluceau - Rocquencourt, Paris, France
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Song B, Bian Q, Shao CH, Liu AA, Jing W, Liu R, Zhang YJ, Zhou YQ, Li G, Jin G. Sox2 function as a negative regulator to control HAMP expression. Biol Res 2015; 48:23. [PMID: 25943891 PMCID: PMC4440282 DOI: 10.1186/s40659-015-0013-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2014] [Accepted: 04/16/2015] [Indexed: 11/24/2022] Open
Abstract
Background Hepcidin, encoding by HAMP gene, is the pivotal regulator of iron metabolism, controlling the systemic absorption and transportation of irons from intracellular stores. Abnormal levels of HAMP expression alter plasma iron parameters and lead to iron metabolism disorders. Therefore, it is an important goal to understand the mechanisms controlling HAMP gene expression. Results Overexpression of Sox2 decrease basal expression of HAMP or induced by IL-6 or BMP-2, whereas, knockdown of Sox2 can increase HAMP expression, furthermore, two potential Sox2-binding sites were identified within the human HAMP promoter. Indeed, luciferase experiments demonstrated that deletion of any Sox2-binding site impaired the negative regulation of Sox2 on HAMP promoter transcriptional activity in basal conditions. ChIP experiments showed that Sox2 could directly bind to these sites. Finally, we verified the role of Sox2 to negatively regulate HAMP expression in human primary hepatocytes. Conclusion We found that Sox2 as a novel factor to bind with HAMP promoter to negatively regulate HAMP expression, which may be further implicated as a therapeutic option for the amelioration of HAMP-overexpression-related diseases, including iron deficiency anemia. Electronic supplementary material The online version of this article (doi:10.1186/s40659-015-0013-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Bin Song
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - Qi Bian
- Department of Nephrology, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - Cheng-Hao Shao
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - An-An Liu
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - Wei Jing
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - Rui Liu
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - Yi-Jie Zhang
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - Ying-Qi Zhou
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - Gang Li
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
| | - Gang Jin
- Department of General Surgery, Changhai Hospital, Second Military Medical University, Shanghai, 200433, China.
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Abstract
As an essential element, iron plays a central role in many physiological processes, including redox balance, inflammation, energy metabolism, and environment sensing. Perturbations in iron homeostasis are associated with several conditions, including hyperglycemia and diabetes, both of which have been studied in patients and animal models. To clarify the pleiotropic role of iron homeostasis in diabetes development, the early studies on diseases with iron-overload, studies on clinical iron depletion therapies, associations between iron-related genetic polymorphisms and diabetes, and etiological mechanisms underlying iron perturbations-impaired insulin secretion and insulin sensitivity were carefully reviewed and discussed. Hereditary hemochromatosis, transfusion-dependent thalassemia, and excess heme iron intake can increase the risk of developing diabetes. Genetically modified mice and mice fed a high-iron diet present with discrepant phenotypes due to differences in tissue iron distribution. Moreover, several genetic polymorphisms related to iron homeostasis have been associated with the risk of developing diabetes. Tightly controlled iron metabolism is essential for insulin secretion and insulin sensitivity, and iron overload in pancreatic islets alters reactive oxygen species (ROS) generation, as well as hypoxia-inducible factor-1α (HIF-1α) stability and adenosine triphosphate (ATP) synthesis, thereby impairing the function and viability of β-cells. Decreased levels of adiponectin, macrophage-mediated inflammation, and ROS-mediated liver kinase B1 (LKB1)/adenosine monophosphate-activated protein kinase (AMPK) activation can contribute to iron overload-induced insulin resistance, whereas iron deficiency could also participate in obesity-related inflammation, hypoxia, and insulin resistance. Because iron homeostasis is closely correlated with many metabolic processes, future studies are needed in order to elucidate the finely tuned network among iron homeostasis, carbohydrate and lipid metabolism, inflammation, and hypoxia.
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Affiliation(s)
- Xinhui Wang
- Department of Nutrition, Research Center for Nutrition and Health, Institute of Nutrition and Food Safety, School of Public Health, School of Medicine, Zhejiang University, 866 Yuhangtang Road, Hangzhou, Zhejiang, 310058, China
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Zhang Y, Cheng Y, Wang N, Zhang Q, Wang K. The action of JAK, SMAD and ERK signal pathways on hepcidin suppression by polysaccharides from Angelica sinensis in rats with iron deficiency anemia. Food Funct 2015; 5:1381-8. [PMID: 24752529 DOI: 10.1039/c4fo00006d] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A crude polysaccharide was obtained by water extraction and ethanol precipitation from the root of Angelica sinensis (AS) to investigate its suppressive effect on hepcidin expression in rats with iron deficiency anemia (IDA). In this study, we showed that the Angelica sinensis polysaccharide (ASP) was mainly composed of arabinose, glucose and galactose in a molar ratio of 1 : 2.5 : 7.5, with the molecular weight of 72 900 Da and the sugar content of 95.1%. ASP markedly decreased hepcidin expression by suppressing the expression of JAK1/2, phospho-JAK1/2, phospho-SMAD1/5/8, phospho-ERK1/2, and promoting the expression of SMAD7 in the liver. These findings suggest that ASP can prevent the janus-kinase (JAK), son of mother against decapentaplegic (SMAD) and extracellular signal-regulated kinase (ERK) pathways to down-regulate hepcidin expression in IDA rats, and may be useful for the treatments of diseases induced by hepcidin over-expression.
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Affiliation(s)
- Yu Zhang
- Union Hospital of Huazhong University of Science and Technology, Department of Pharmacy, No. 1227, Jiefang Road, 430030 Wuhan, China
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Foka P, Dimitriadis A, Kyratzopoulou E, Giannimaras DA, Sarno S, Simos G, Georgopoulou U, Mamalaki A. A complex signaling network involving protein kinase CK2 is required for hepatitis C virus core protein-mediated modulation of the iron-regulatory hepcidin gene expression. Cell Mol Life Sci 2014; 71:4243-58. [PMID: 24718935 PMCID: PMC11114079 DOI: 10.1007/s00018-014-1621-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 02/25/2014] [Accepted: 03/24/2014] [Indexed: 12/18/2022]
Abstract
Hepatitis C virus (HCV) infection is associated with hepatic iron overload and elevated serum iron that correlate to poor antiviral responses. Hepcidin (HAMP), a 25-aa cysteine-rich liver-specific peptide, controls iron homeostasis. Its expression is up-regulated in inflammation and iron excess. HCV-mediated hepcidin regulation remains controversial. Chronic HCV patients possess relatively low hepcidin levels; however, elevated HAMP mRNA has been reported in HCV core transgenic mice and HCV replicon-expressing cells. We investigated the effect of HCV core protein on HAMP gene expression and delineated the complex interplay of molecular mechanisms involved. HCV core protein up-regulated HAMP promoter activity, mRNA, and secreted protein levels. Enhanced promoter activity was abolished by co-transfections of core with HAMP promoter constructs containing mutated/deleted BMP and STAT binding sites. Dominant negative constructs, pharmacological inhibitors, and silencing experiments against STAT3 and SMAD4 confirmed the participation of both pathways in HAMP gene regulation by core protein. STAT3 and SMAD4 expression levels were found increased in the presence of HCV core, which orchestrated SMAD4 translocation into the nucleus and STAT3 phosphorylation. To further understand the mechanisms governing the core effect, the role of the JAK/STAT-activating kinase CK2 was investigated. A CK2-dominant negative construct, a CK2-specific inhibitor, and RNAi interference abrogated the core-induced increase on HAMP promoter activity, mRNA, and protein levels, while CK2 acted in synergy with core to significantly enhance HAMP gene expression. Therefore, HCV core up-regulates HAMP gene transcription via a complex signaling network that requires both SMAD/BMP and STAT3 pathways and CK2 involvement.
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Affiliation(s)
- Pelagia Foka
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
- Laboratory of Molecular Virology, Hellenic Pasteur Institute, Athens, Greece
| | - Alexios Dimitriadis
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Eleni Kyratzopoulou
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Dionysios A. Giannimaras
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
| | - Stefania Sarno
- Department of Biomedical Sciences, University of Padova, Padua, Italy
| | - George Simos
- Laboratory of Biochemistry, Faculty of Medicine, University of Thessaly, Larissa, Greece
| | - Urania Georgopoulou
- Laboratory of Molecular Virology, Hellenic Pasteur Institute, Athens, Greece
| | - Avgi Mamalaki
- Laboratory of Molecular Biology and Immunobiotechnology, Department of Biochemistry, Hellenic Pasteur Institute, Athens, Greece
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Kanamori Y, Murakami M, Matsui T, Funaba M. Hepcidin expression in liver cells: evaluation of mRNA levels and transcriptional regulation. Gene 2014; 546:50-5. [DOI: 10.1016/j.gene.2014.05.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2014] [Revised: 05/07/2014] [Accepted: 05/19/2014] [Indexed: 12/11/2022]
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Ravasi G, Pelucchi S, Greni F, Mariani R, Giuliano A, Parati G, Silvestri L, Piperno A. Circulating factors are involved in hypoxia-induced hepcidin suppression. Blood Cells Mol Dis 2014; 53:204-10. [PMID: 25065484 DOI: 10.1016/j.bcmd.2014.06.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2014] [Accepted: 06/30/2014] [Indexed: 12/21/2022]
Abstract
Hepcidin transcription is strongly down-regulated under hypoxic conditions, however whether hypoxia inhibits hepcidin directly or indirectly is still unknown. We investigated the time course of hypoxia-mediated hepcidin down-regulation in vivo in healthy volunteers exposed to hypobaric hypoxia at high altitude and, based on the hypothesis that circulating factors are implicated in hepcidin inhibition, we analyzed the effect of sera of these volunteers exposed to normoxia and hypoxia on hepcidin expression in Huh-7 cell lines. Hypoxia led to a significant hepcidin down-regulation in vivo that was almost complete within 72h of exposure and followed erythropoietin induction. This delay in hepcidin down-regulation suggests the existence of soluble factor/s regulating hepcidin production. We then stimulated HuH-7 cells with normoxic and hypoxic sera to analyze the effects of sera on hepcidin regulation. Hypoxic sera had a significant inhibitory effect on hepcidin promoter activity assessed by a luciferase assay, although the amount of such decrease was not as relevant as that observed in vivo. Cellular mRNA analysis showed that a number of volunteers' sera inhibited hepcidin expression, concurrently with ID1 inhibition, suggesting that inhibitory factor(s) may act through the SMAD-pathway.
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Affiliation(s)
- Giulia Ravasi
- Department of Health Science, University Milano-Bicocca, Monza, Italy
| | - Sara Pelucchi
- Department of Health Science, University Milano-Bicocca, Monza, Italy
| | - Federico Greni
- Department of Health Science, University Milano-Bicocca, Monza, Italy
| | | | - Andrea Giuliano
- Department of Health Science, University Milano-Bicocca, Monza, Italy; Department of Cardiology, Italian Institute for Auxology, Milan, Italy
| | - Gianfranco Parati
- Department of Health Science, University Milano-Bicocca, Monza, Italy; San Gerardo Hospital, Monza, Italy; Department of Cardiology, Italian Institute for Auxology, Milan, Italy
| | - Laura Silvestri
- Division of Genetics and Cell Biology, San Raffaele Scientific Institute and Vita Salute University, Milan, Italy
| | - Alberto Piperno
- Department of Health Science, University Milano-Bicocca, Monza, Italy; San Gerardo Hospital, Monza, Italy; Consortium of Human Molecular Genetics, Monza, Italy.
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40
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Gebhardt R, Matz-Soja M. Liver zonation: Novel aspects of its regulation and its impact on homeostasis. World J Gastroenterol 2014; 20:8491-8504. [PMID: 25024605 PMCID: PMC4093700 DOI: 10.3748/wjg.v20.i26.8491] [Citation(s) in RCA: 179] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/20/2014] [Accepted: 04/09/2014] [Indexed: 02/06/2023] Open
Abstract
Liver zonation, the spatial separation of the immense spectrum of different metabolic pathways along the liver sinusoids, is fundamental for proper functioning of this organ. Recent progress in elucidating localization and interactions of different metabolic pathways by using “omics” techniques and novel approaches to couple them with refined spatial resolution and in characterizing novel master regulators of zonation by using transgenic mice has created the basis for a deeper understanding of core mechanisms of zonation and their impact on liver physiology, pathology and metabolic diseases. This review summarizes the fascinating technical achievements for investigating liver zonation and the elucidation of an emerging network of master regulators of zonation that keep the plethora of interrelated and sometimes opposing functions of the liver in balance with nutritional supply and specific requirements of the entire body. In addition, a brief overview is given on newly described zonated functions and novel details on how diverse the segmentation of metabolic zonation may be. From these facts and developments a few fundamental principles are inferred which seem to rule zonation of liver parenchyma. In addition, we identify important questions that still need to be answered as well as interesting fields of research such as the connection of zonation with circadian rhythm and gender dimorphism which need to be pushed further, in order to improve our understanding of metabolic zonation. Finally, an outlook is given on how disturbance of liver zonation and its regulation may impact on liver pathology and the development of metabolic diseases.
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Abstract
Bone morphogenetic proteins (BMPs) are members of the transforming growth factor-beta (TGF-β) superfamily of signaling molecules. In addition to protean roles in embryonic development, germ-line specification, and cellular differentiation, a central role in iron homeostasis has recently been demonstrated for certain BMPs. Specifically, BMP6 serves to relate hepatic iron stores to the hepatocellular expression of the iron-regulatory hormone hepcidin. This regulation occurs via cellular SMAD-signaling molecules and is strongly modulated by the BMP coreceptor hemojuvelin (HJV). Mutations in certain genes influencing signaling to hepcidin via the BMP/SMAD pathway are associated with human disorders of iron metabolism, such as hereditary hemochromatosis and iron-refractory iron-deficiency anemia. Evidence suggests that signals in addition to iron stores influence hepcidin expression via the BMP/SMAD pathway. This review summarizes the details of BMP/SMAD signaling, with a particular focus on its role in iron homeostasis and iron-related diseases.
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Affiliation(s)
- Nermi L Parrow
- Division of Molecular and Clinical Nutrition, National Institute of Diabetes, Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
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42
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Core AB, Canali S, Babitt JL. Hemojuvelin and bone morphogenetic protein (BMP) signaling in iron homeostasis. Front Pharmacol 2014; 5:104. [PMID: 24860505 PMCID: PMC4026703 DOI: 10.3389/fphar.2014.00104] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/21/2014] [Indexed: 12/13/2022] Open
Abstract
Mutations in hemojuvelin (HJV) are the most common cause of the juvenile-onset form of the iron overload disorder hereditary hemochromatosis. The discovery that HJV functions as a co-receptor for the bone morphogenetic protein (BMP) family of signaling molecules helped to identify this signaling pathway as a central regulator of the key iron hormone hepcidin in the control of systemic iron homeostasis. This review highlights recent work uncovering the mechanism of action of HJV and the BMP-SMAD signaling pathway in regulating hepcidin expression in the liver, as well as additional studies investigating possible extra-hepatic functions of HJV. This review also explores the interaction between HJV, the BMP-SMAD signaling pathway and other regulators of hepcidin expression in systemic iron balance.
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Affiliation(s)
- Amanda B Core
- Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Program in Anemia Signaling Research Boston, MA, USA
| | - Susanna Canali
- Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Program in Anemia Signaling Research Boston, MA, USA
| | - Jodie L Babitt
- Division of Nephrology, Program in Membrane Biology, Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Program in Anemia Signaling Research Boston, MA, USA
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Poli M, Asperti M, Ruzzenenti P, Regoni M, Arosio P. Hepcidin antagonists for potential treatments of disorders with hepcidin excess. Front Pharmacol 2014; 5:86. [PMID: 24808863 PMCID: PMC4009444 DOI: 10.3389/fphar.2014.00086] [Citation(s) in RCA: 91] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/07/2014] [Indexed: 12/20/2022] Open
Abstract
The discovery of hepcidin clarified the basic mechanism of the control of systemic iron homeostasis. Hepcidin is mainly produced by the liver as a propeptide and processed by furin into the mature active peptide. Hepcidin binds ferroportin, the only cellular iron exporter, causing the internalization and degradation of both. Thus hepcidin blocks iron export from the key cells for dietary iron absorption (enterocytes), recycling of hemoglobin iron (the macrophages) and the release of storage iron from hepatocytes, resulting in the reduction of systemic iron availability. The BMP/HJV/SMAD pathway is the major regulator of hepcidin expression that responds to iron status. Also inflammation stimulates hepcidin via the IL6/STAT3 pathway with a support of an active BMP/HJV/SMAD pathway. In some pathological conditions hepcidin level is inadequately elevated and reduces iron availability in the body, resulting in anemia. These conditions occur in the genetic iron refractory iron deficiency anemia and the common anemia of chronic disease (ACD) or anemia of inflammation. Currently, there is no definite treatment for ACD. Erythropoiesis-stimulating agents and intravenous iron have been proposed in some cases but they are scarcely effective and may have adverse effects. Alternative approaches aimed to a pharmacological control of hepcidin expression have been attempted, targeting different regulatory steps. They include hepcidin sequestering agents (antibodies, anticalins, and aptamers), inhibitors of BMP/SMAD or of IL6/STAT3 pathway or of hepcidin transduction (siRNA/shRNA) or ferroportin stabilizers. In this review we summarized the biochemical interactions of the proteins involved in the BMP/HJV/SMAD pathway and its natural inhibitors, the murine and rat models with high hepcidin levels currently available and finally the progresses in the development of hepcidin antagonists, with particular attention to the role of heparins and heparin sulfate proteoglycans in hepcidin expression and modulation of the BMP6/SMAD pathway.
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Affiliation(s)
- Maura Poli
- Molecular Biology Laboratory, Department of Molecular and Translational Medicine, University of Brescia Brescia, Italy
| | - Michela Asperti
- Molecular Biology Laboratory, Department of Molecular and Translational Medicine, University of Brescia Brescia, Italy
| | - Paola Ruzzenenti
- Molecular Biology Laboratory, Department of Molecular and Translational Medicine, University of Brescia Brescia, Italy
| | - Maria Regoni
- Molecular Biology Laboratory, Department of Molecular and Translational Medicine, University of Brescia Brescia, Italy
| | - Paolo Arosio
- Molecular Biology Laboratory, Department of Molecular and Translational Medicine, University of Brescia Brescia, Italy
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Worthen CA, Enns CA. The role of hepatic transferrin receptor 2 in the regulation of iron homeostasis in the body. Front Pharmacol 2014; 5:34. [PMID: 24639653 PMCID: PMC3944196 DOI: 10.3389/fphar.2014.00034] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 02/18/2014] [Indexed: 12/22/2022] Open
Abstract
Fine-tuning of body iron is required to prevent diseases such as iron-overload and anemia. The putative iron sensor, transferrin receptor 2 (TfR2), is expressed in the liver and mutations in this protein result in the iron-overload disease Type III hereditary hemochromatosis (HH). With the loss of functional TfR2, the liver produces about 2-fold less of the peptide hormone hepcidin, which is responsible for negatively regulating iron uptake from the diet. This reduction in hepcidin expression leads to the slow accumulation of iron in the liver, heart, joints, and pancreas and subsequent cirrhosis, heart disease, arthritis, and diabetes. TfR2 can bind iron-loaded transferrin (Tf) in the bloodstream, and hepatocytes treated with Tf respond with a 2-fold increase in hepcidin expression through stimulation of the bone morphogenetic protein (BMP)-signaling pathway. Loss of functional TfR2 or its binding partner, the original HH protein, results in a loss of this transferrin-sensitivity. While much is known about the trafficking and regulation of TfR2, the mechanism of its transferrin-sensitivity through the BMP-signaling pathway is still not known.
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Affiliation(s)
- Christal A Worthen
- Department of Cell and Developmental Biology, Oregon Health and Science University Portland, OR, USA
| | - Caroline A Enns
- Department of Cell and Developmental Biology, Oregon Health and Science University Portland, OR, USA
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45
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Frazer DM, Anderson GJ. The regulation of iron transport. Biofactors 2014; 40:206-14. [PMID: 24132807 DOI: 10.1002/biof.1148] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Revised: 09/02/2013] [Accepted: 09/06/2013] [Indexed: 01/01/2023]
Abstract
Iron is an essential nutrient, but its concentration and distribution in the body must be tightly controlled due to its inherent toxicity and insolubility in aqueous solution. Living systems have successfully overcome these potential limitations by evolving a range of iron binding proteins and transport systems that effectively maintain iron in a nontoxic and soluble form for much, if not all, of its time within the body. In the circulation, iron is transported to target organs bound to the serum iron binding protein transferrin. Individual cells modulate their uptake of transferrin-bound iron depending on their iron requirements, using both transferrin receptor 1-dependent and independent pathways. Once inside the cell, iron can be chaperoned to sites of need or, if in excess, stored within ferritin. Iron is released from cells by the iron export protein ferroportin1, which requires the ferroxidase activity of ceruloplasmin or hephestin to load iron safely onto transferrin. The regulation of iron export is controlled predominantly at the systemic level by the master regulator of iron homeostasis hepcidin. Hepcidin, in turn, responds to changes in body iron demand, making use of a range of regulatory mechanisms that center on the bone morphogenetic protein signaling pathway. This review provides an overview of recent advances in the field of iron metabolism and outlines the key components of the iron transport and regulation systems.
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Affiliation(s)
- David M Frazer
- Iron Metabolism Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Qld, Australia
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46
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Abstract
A classic Girl Scout song says, "Make new friends/but keep the old/One is silver/and the other gold." This review focuses on the past decade of discovery in the field of iron homeostasis, which has identified "new friends" or key modifiers of the critical systemic iron regulator, hepcidin antimicrobial peptide. The foundation for these discoveries has been the identification of mutated genes in well-characterized cohorts of patients with inherited hemochromatosis from across the globe. Transgenic mouse models of iron overload and iron-restricted anemia have also contributed to understanding molecular pathophysiology in ways that could never be accomplished in human subjects alone. The majority of these newly discovered molecules coordinate signaling through the bone morphogenetic protein pathway of ligands, receptors and coreceptors, intracellular signaling and transcription. The discovery of these proteins and their interactions with "old friends," such as the 1st known hereditary hemochromatosis gene product, HFE and transferrin receptor, has opened the field of iron homeostasis to include regulatory networks involving signal transduction pathways, in particular, the mitogen-activated protein kinase and Smad pathways. These newly discovered partnerships have also made way for opportunities to develop novel therapeutics for the treatment of iron regulatory disorders, including hemochromatosis.
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A multi-scale model of hepcidin promoter regulation reveals factors controlling systemic iron homeostasis. PLoS Comput Biol 2014; 10:e1003421. [PMID: 24391488 PMCID: PMC3879105 DOI: 10.1371/journal.pcbi.1003421] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Accepted: 11/08/2013] [Indexed: 01/24/2023] Open
Abstract
Systemic iron homeostasis involves a negative feedback circuit in which the expression level of the peptide hormone hepcidin depends on and controls the iron blood levels. Hepcidin expression is regulated by the BMP6/SMAD and IL6/STAT signaling cascades. Deregulation of either pathway causes iron-related diseases such as hemochromatosis or anemia of inflammation. We quantitatively analyzed how BMP6 and IL6 control hepcidin expression. Transcription factor (TF) phosphorylation and reporter gene expression were measured under co-stimulation conditions, and the promoter was perturbed by mutagenesis. Using mathematical modeling, we systematically analyzed potential mechanisms of cooperative and competitive promoter regulation by the transcription factors, and experimentally validated the model predictions. Our results reveal that hepcidin cross-regulation primarily occurs by combinatorial transcription factor binding to the promoter, whereas signaling crosstalk is insignificant. We find that the presence of two BMP-responsive elements enhances the steepness of the promoter response towards the iron-sensing BMP signaling axis, which promotes iron homeostasis in vivo. IL6 co-stimulation reduces the promoter sensitivity towards the BMP signal, because the SMAD and STAT transcription factors compete for recruiting RNA polymerase to the transcription start site. This may explain why inflammatory signals disturb iron homeostasis in anemia of inflammation. Taken together, our results reveal why the iron homeostasis circuit is sensitive to perturbations implicated in disease. The nutritional iron uptake is tightly regulated because the body has limited capacity of iron excretion. Mammals maintain iron homeostasis by a negative feedback loop, in which the peptide hepcidin senses the iron blood level and controls iron resorption. Molecular perturbations in the homeostasis loop lead to iron-related diseases such as hemochromatosis or anemia of inflammation. Quantitative studies are required to understand the dynamics of the iron homeostasis circuitry in health and disease. We investigated how the biological activity of hepcidin is regulated by combining experiments with mathematical modeling. We present a multi-scale model that describes the signaling network and the gene promoter controlling hepcidin expression. Possible scenarios of hepcidin regulation were systematically tested against experimental data, and interpreted using a network model of iron metabolism in vivo. The analysis showed that the presence of multiple redundant regulatory elements in the hepcidin gene promoter facilitates homeostasis, because changes in iron blood levels are sensed with high sensitivity. We further suggest that inflammatory signals establish molecular competition at the hepcidin promoter, thereby reducing its iron sensitivity and leading to a loss of homeostasis in anemia of inflammation. We conclude that quantitative insights into hepcidin expression regulation explain features of systemic iron homeostasis.
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Unbiased RNAi screen for hepcidin regulators links hepcidin suppression to proliferative Ras/RAF and nutrient-dependent mTOR signaling. Blood 2014; 123:1574-85. [PMID: 24385536 DOI: 10.1182/blood-2013-07-515957] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The hepatic hormone hepcidin is a key regulator of systemic iron metabolism. Its expression is largely regulated by 2 signaling pathways: the "iron-regulated" bone morphogenetic protein (BMP) and the inflammatory JAK-STAT pathways. To obtain broader insights into cellular processes that modulate hepcidin transcription and to provide a resource to identify novel genetic modifiers of systemic iron homeostasis, we designed an RNA interference (RNAi) screen that monitors hepcidin promoter activity after the knockdown of 19 599 genes in hepatocarcinoma cells. Interestingly, many of the putative hepcidin activators play roles in signal transduction, inflammation, or transcription, and affect hepcidin transcription through BMP-responsive elements. Furthermore, our work sheds light on new components of the transcriptional machinery that maintain steady-state levels of hepcidin expression and its responses to the BMP- and interleukin-6-triggered signals. Notably, we discover hepcidin suppression mediated via components of Ras/RAF MAPK and mTOR signaling, linking hepcidin transcriptional control to the pathways that respond to mitogen stimulation and nutrient status. Thus using a combination of RNAi screening, reverse phase protein arrays, and small molecules testing, we identify links between the control of systemic iron homeostasis and critical liver processes such as regeneration, response to injury, carcinogenesis, and nutrient metabolism.
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De Falco L, Sanchez M, Silvestri L, Kannengiesser C, Muckenthaler MU, Iolascon A, Gouya L, Camaschella C, Beaumont C. Iron refractory iron deficiency anemia. Haematologica 2013; 98:845-53. [PMID: 23729726 DOI: 10.3324/haematol.2012.075515] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Iron refractory iron deficiency anemia is a hereditary recessive anemia due to a defect in the TMPRSS6 gene encoding Matriptase-2. This protein is a transmembrane serine protease that plays an essential role in down-regulating hepcidin, the key regulator of iron homeostasis. Hallmarks of this disease are microcytic hypochromic anemia, low transferrin saturation and normal/high serum hepcidin values. The anemia appears in the post-natal period, although in some cases it is only diagnosed in adulthood. The disease is refractory to oral iron treatment but shows a slow response to intravenous iron injections and partial correction of the anemia. To date, 40 different Matriptase-2 mutations have been reported, affecting all the functional domains of the large ectodomain of the protein. In vitro experiments on transfected cells suggest that Matriptase-2 cleaves Hemojuvelin, a major regulator of hepcidin expression and that this function is altered in this genetic form of anemia. In contrast to the low/undetectable hepcidin levels observed in acquired iron deficiency, in patients with Matriptase-2 deficiency, serum hepcidin is inappropriately high for the low iron status and accounts for the absent/delayed response to oral iron treatment. A challenge for the clinicians and pediatricians is the recognition of the disorder among iron deficiency and other microcytic anemias commonly found in pediatric patients. The current treatment of iron refractory iron deficiency anemia is based on parenteral iron administration; in the future, manipulation of the hepcidin pathway with the aim of suppressing it might become an alternative therapeutic approach.
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Díaz V, Gammella E, Recalcati S, Santambrogio P, Naldi AM, Vogel J, Gassmann M, Cairo G. Liver iron modulates hepcidin expression during chronically elevated erythropoiesis in mice. Hepatology 2013; 58:2122-32. [PMID: 23744538 DOI: 10.1002/hep.26550] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/22/2013] [Indexed: 01/01/2023]
Abstract
UNLABELLED The liver-derived peptide hepcidin controls the balance between iron demand and iron supply. By inhibiting the iron export activity of ferroportin, hepcidin modulates iron absorption and delivery from the body's stores. The regulation of hepcidin, however, is not completely understood and includes a variety of different signals. We studied iron metabolism and hepcidin expression in mice constitutively overexpressing erythropoietin (Epo) (Tg6 mice), which leads to excessive erythropoiesis. We observed a very strong down-regulation of hepcidin in Tg6 mice that was accompanied by a strong increase in duodenal expression of ferroportin and divalent metal tranporter-1, as well as enhanced duodenal iron absorption. Despite these compensatory mechanisms, Tg6 mice displayed marked circulating iron deficiency and low levels of iron in liver, spleen, and muscle. To elucidate the primary signal affecting hepcidin expression during chronically elevated erythropoiesis, we increased iron availability by either providing iron (thus further increasing the hematocrit) or reducing erythropoiesis-dependent iron consumption by means of splenectomy. Both treatments increased liver iron and up-regulated hepcidin expression and the BMP6/SMAD pathway despite continuously high plasma Epo levels and sustained erythropoiesis. This suggests that hepcidin expression is not controlled by erythropoietic signals directly in this setting. Rather, these results indicate that iron consumption for erythropoiesis modulates liver iron content, and ultimately BMP6 and hepcidin. Analysis of the BMP6/SMAD pathway targets showed that inhibitor of DNA binding 1 (ID1) and SMAD7, but not transmembrane serine protease 6 (TMPRSS6), were up-regulated by increased iron availability and thus may be involved in setting the upper limit of hepcidin. CONCLUSION We provide evidence that under conditions of excessive and effective erythropoiesis, liver iron regulates hepcidin expression through the BMP6/SMAD pathway.
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Affiliation(s)
- Víctor Díaz
- Institute of Veterinary Physiology, Vetsuisse Faculty, and Zurich Center for Integrative Human Physiology (ZIHP), and University of Zurich, Switzerland; Department of Health and Human Performance, Faculty of Sports Science, INEF, Technical University of Madrid, Spain
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