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Abadía Molina C, Goñi Ros N, González Tarancón R, Rello Varas L, Recasens Flores MDV, Izquierdo Álvarez S. Hereditary haemochromatosis: Prevalence and characterization of the disease in a tertiary hospital in Aragon. Med Clin (Barc) 2024:S0025-7753(24)00391-9. [PMID: 39003111 DOI: 10.1016/j.medcli.2024.05.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Revised: 05/09/2024] [Accepted: 05/13/2024] [Indexed: 07/15/2024]
Abstract
BACKGROUND The main genetic cause of iron overload is haemochromatosis (HC). In recent years, the study of non-HFE genes (HFE2, HJV, HAMP, TRF2, SLC40A1, and BMP6) has become relevant thanks to next-generation sequencing (NGS) and multiplex ligation-dependent probe amplification (MLPA) techniques. Our objectives were to estimate the prevalence of both HFE (C282Y/HY63D variants) and non-HFE variants attending a tertiary hospital in Aragón, to predict the effect of the variants on the protein, and to establish a genotype-phenotype correlation evaluating with the clinical context. METHODS Retrospective descriptive study from 2006 to 2020 of patients attended at genetic consultation in a reference hospital for HC in Aragon. We calculated prevalence of HFE and non-HFE variants. We analysed non-HFE genes (HFE2, HJV, HAMP, TRF2, SLC40A1, and BMP6), used bioinformatics tools, consulted different databases and measured clinical parameters (laboratory and imaging). RESULTS The prevalence of C282Y homozygous was 5.95% respect the total of cases and 0.025% respect our population. The prevalence of non-HFE HC variants was 1.94% respect the total of cases and 0.008% respect our population. We found 27 variants in non-HFE genes and 4 in HFE gene, of which 6 were classified as variant of uncertain clinical significance (VUS), or likely pathogenic or pathogenic according to the ACMG classification criteria. CONCLUSION Our prevalence results are as expected, and similar to those obtained by other studies. Although some of the genetic findings explain the clinical symptoms of some of our patients, we remain have a high number of patients without a clear molecular diagnosis.
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Affiliation(s)
- Claudia Abadía Molina
- Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain.
| | - Nuria Goñi Ros
- Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - Ricardo González Tarancón
- Genetic Section, Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - Luis Rello Varas
- Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | | | - Silvia Izquierdo Álvarez
- Genetic Section, Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
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2
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Fisher AL, Wang CY, Xu Y, Phillips S, Paulo JA, Małachowska B, Xiao X, Fendler W, Mancias JD, Babitt JL. Quantitative proteomics and RNA-sequencing of mouse liver endothelial cells identify novel regulators of BMP6 by iron. iScience 2023; 26:108555. [PMID: 38125029 PMCID: PMC10730383 DOI: 10.1016/j.isci.2023.108555] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 09/29/2023] [Accepted: 11/20/2023] [Indexed: 12/23/2023] Open
Abstract
Hepcidin is the master hormone governing systemic iron homeostasis. Iron regulates hepcidin by activating bone morphogenetic protein (BMP)6 expression in liver endothelial cells (LECs), but the mechanisms are incompletely understood. To address this, we performed proteomics and RNA-sequencing on LECs from iron-adequate and iron-loaded mice. Gene set enrichment analysis identified transcription factors activated by high iron, including Nrf-2, which was previously reported to contribute to BMP6 regulation, and c-Jun. Jun (encoding c-Jun) knockdown blocked Bmp6 but not Nrf-2 pathway induction by iron in LEC cultures. Chromatin immunoprecipitation of mouse livers showed iron-dependent c-Jun binding to predicted sites in Bmp6 regulatory regions. Finally, c-Jun inhibitor blunted induction of Bmp6 and hepcidin, but not Nrf-2 activity, in iron-loaded mice. However, Bmp6 and iron parameters were unchanged in endothelial Jun knockout mice. Our data suggest that c-Jun participates in iron-mediated BMP6 regulation independent of Nrf-2, though the mechanisms may be redundant and/or multifactorial.
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Affiliation(s)
- Allison L. Fisher
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Chia-Yu Wang
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Yang Xu
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Sydney Phillips
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Joao A. Paulo
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Beata Małachowska
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, Lodz, Poland
- Department of Radiation Oncology, Albert Einstein College of Medicine, NYC, NY, USA
| | - Xia Xiao
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Wojciech Fendler
- Department of Biostatistics and Translational Medicine, Medical University of Lodz, Lodz, Poland
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Joseph D. Mancias
- Department of Radiation Oncology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Jodie L. Babitt
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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3
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Xiao X, Xu Y, Moschetta GA, Yu Y, Fisher AL, Alfaro-Magallanes VM, McMillen S, Phillips S, Wang CY, Christian J, Babitt JL. BMP5 contributes to hepcidin regulation and systemic iron homeostasis in mice. Blood 2023; 142:1312-1322. [PMID: 37478395 PMCID: PMC10613724 DOI: 10.1182/blood.2022019195] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Revised: 06/14/2023] [Accepted: 06/22/2023] [Indexed: 07/23/2023] Open
Abstract
Hepcidin is the master regulator of systemic iron homeostasis. The bone morphogenetic protein (BMP) signaling pathway is a critical regulator of hepcidin expression in response to iron and erythropoietic drive. Although endothelial-derived BMP6 and BMP2 ligands have key functional roles as endogenous hepcidin regulators, both iron and erythropoietic drives still regulate hepcidin in mice lacking either or both ligands. Here, we used mice with an inactivating Bmp5 mutation (Bmp5se), either alone or together with a global or endothelial Bmp6 knockout, to investigate the functional role of BMP5 in hepcidin and systemic iron homeostasis regulation. We showed that Bmp5se-mutant mice exhibit hepcidin deficiency at age 10 days, blunted hepcidin induction in response to oral iron gavage, and mild liver iron loading when fed on a low- or high-iron diet. Loss of 1 or 2 functional Bmp5 alleles also leads to increased iron loading in Bmp6-heterozygous mice and more profound hemochromatosis in global or endothelial Bmp6-knockout mice. Moreover, double Bmp5- and Bmp6-mutant mice fail to induce hepcidin in response to long-term dietary iron loading. Finally, erythroferrone binds directly to BMP5 and inhibits BMP5 induction of hepcidin in vitro. Although erythropoietin suppresses hepcidin in Bmp5se-mutant mice, it fails to suppress hepcidin in double Bmp5- and Bmp6-mutant males. Together, these data demonstrate that BMP5 plays a functional role in hepcidin and iron homeostasis regulation, particularly under conditions in which BMP6 is limited.
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Affiliation(s)
- Xia Xiao
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Yang Xu
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Gillian A. Moschetta
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Yang Yu
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Allison L. Fisher
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Víctor M. Alfaro-Magallanes
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
- LFE Research Group, Department of Health and Human Performance, Faculty of Physical Activity and Sport Sciences, Universidad Politécnica de Madrid, Madrid, Spain
| | - Shasta McMillen
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Sydney Phillips
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Chia-Yu Wang
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Jan Christian
- Division of Hematology and Hematologic Malignancies, Department of Neurobiology and Internal Medicine, University of Utah, Salt Lake City, UT
| | - Jodie L. Babitt
- Nephrology Division and Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, MA
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Olynyk JK, Grainger R, Currie H, Ramm LE, Ramm GA. The ancestral haplotype markers HLA -A3 and B7 do not influence the likelihood of advanced hepatic fibrosis or cirrhosis in HFE hemochromatosis. Sci Rep 2023; 13:7775. [PMID: 37179448 PMCID: PMC10183001 DOI: 10.1038/s41598-023-35028-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 05/11/2023] [Indexed: 05/15/2023] Open
Abstract
Advanced hepatic fibrosis occurs in up to 25% of individuals with C282Y homozygous hemochromatosis. Our aim was to determine whether human leukocyte antigen (HLA)-A3 and B7 alleles act as genetic modifiers of the likelihood of advanced hepatic fibrosis. Between 1972 and 2013, 133 HFE C282Y homozygous individuals underwent clinical and biochemical evaluation, HLA typing, liver biopsy for fibrosis staging and phlebotomy treatment. Hepatic fibrosis was graded according to Scheuer as F0-2 (low grade hepatic fibrosis), F3-4 (advanced hepatic fibrosis), and F4 cirrhosis. We analysed associations between the severity of fibrosis and HLA-A3 homozygosity, heterozygosity or absence, with or without the presence of HLA-B7 using categorical analysis. The mean age of HLA-A3 homozygotes (n = 24), heterozygotes (n = 65) and HLA-A3 null individuals (n = 44) was 40 years. There were no significant differences between the groups for mean(± SEM) serum ferritin levels (1320 ± 296, 1217 ± 124, 1348 ± 188 [Formula: see text]g/L), hepatic iron concentration (178 ± 26, 213 ± 22, 199 ± 29 [Formula: see text]mol/g), mobilizable iron stores (9.9 ± 1.5, 9.5 ± 1.5, 11.5 ± 1.7 g iron removed via phlebotomy), frequency of advanced hepatic fibrosis (5/24[12%], 13/63[19%], 10/42[19%]) or cirrhosis (3/24[21%], 12/63[21%], 4/42[24%]), respectively. The presence or absence of HLA-B7 did not influence the outcome. Thus, HLA-A3 and HLA-B7 alleles are not associated with the risk of advanced hepatic fibrosis or cirrhosis in C282Y hemochromatosis.
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Affiliation(s)
- John K Olynyk
- Medical School, Curtin University, Bentley, WA, Australia.
- Department of Gastroenterology, Fiona Stanley Fremantle Hospital Group, Murdoch, WA, Australia.
| | - Richard Grainger
- Department of Gastroenterology, Fiona Stanley Fremantle Hospital Group, Murdoch, WA, Australia
| | - Helen Currie
- Department of Gastroenterology, Fiona Stanley Fremantle Hospital Group, Murdoch, WA, Australia
| | - Louise E Ramm
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia
- Faculty of Medicine, The University of Queensland, Herston, QLD, Australia
| | - Grant A Ramm
- QIMR-Berghofer Medical Research Institute, Herston, QLD, Australia
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5
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Molina CA, Ros NG, Tarancón RG, Varas LR, Flores VR, Álvarez SI. Hereditary hemochromatosis: An update vision of the laboratory diagnosis. J Trace Elem Med Biol 2023; 78:127194. [PMID: 37163822 DOI: 10.1016/j.jtemb.2023.127194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 03/20/2023] [Accepted: 05/05/2023] [Indexed: 05/12/2023]
Abstract
Haemochromatosis (HC) is an inherited disorder of iron metabolism. The 85-90% of Hereditary hemochromatosis cases are caused by mutations in HFE gene (HC type 1). The remaining 10-15% of HC cases are caused by mutations in other non-HFE genes (HJV, HAMP, TRF2, SLC40A1, BMP6). The study of patients for the diagnosis of HC has an important laboratory approached: analysis of biochemical parameters and genetic studies. To confirm a case, it is necessary to carry out a genetic study of the C282Y and H63D mutations. The presence of C282Y mutation in homozygosis is compatible with the diagnosis of HC type 1. Due to the incomplete penetrance of this mutation and the variable phenotypic expression, the severe forms of the disease are relatively rare. The study of variants in non-HFE genes allows more detailed study of both non-classic HC cases and those with more severe clinical expression. The genotype characterization of a patient not always justified the phenotype expression of the symptoms in this disease. All laboratory clinicians must consider recommendation provide by the experts in the Materia.
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Affiliation(s)
- Claudia Abadía Molina
- Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain.
| | - Nuria Goñi Ros
- Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - Ricardo González Tarancón
- Genetic section, Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - Luis Rello Varas
- Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - Valle Recasens Flores
- Department of Hematology and Hemotherapy, Hospital Universitario Miguel Servet, Zaragoza, Spain
| | - Silvia Izquierdo Álvarez
- Genetic section, Department of Clinical Biochemistry, Hospital Universitario Miguel Servet, Zaragoza, Spain
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6
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Pitfalls in the management of metabolic liver diseases (debate). EGYPTIAN LIVER JOURNAL 2023. [DOI: 10.1186/s43066-023-00246-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023] Open
Abstract
Abstract
Background
The liver has an important role in the different metabolic processes. So, inborn errors of metabolism will result in several metabolic disorders, which can cause acute or chronic liver disease leading to cirrhosis and liver cancer.
Main body
In one of our Egyptian conferences, the United Conference of Hepatogastroenterology and Infectious Diseases (UCHID) 2022, our authors discussed the debates on the management of Wilson’s disease, hereditary hemochromatosis, and alpha one anti-trypsin deficiency.
Conclusion
The session summarized the pitfalls in the management of the 3 serious metabolic liver disorders with focused take-home messages to every physician.
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7
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Iron-dependent BMP6 Regulation in Liver Sinusoidal Endothelial Cells Is Instructed by Hepatocyte-derived Secretory Signals. Hemasphere 2022; 6:e773. [PMID: 36187873 PMCID: PMC9519140 DOI: 10.1097/hs9.0000000000000773] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 08/12/2022] [Indexed: 11/30/2022] Open
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8
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BMP Signaling Pathway in Dentin Development and Diseases. Cells 2022; 11:cells11142216. [PMID: 35883659 PMCID: PMC9317121 DOI: 10.3390/cells11142216] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 07/08/2022] [Accepted: 07/12/2022] [Indexed: 12/27/2022] Open
Abstract
BMP signaling plays an important role in dentin development. BMPs and antagonists regulate odontoblast differentiation and downstream gene expression via canonical Smad and non-canonical Smad signaling pathways. The interaction of BMPs with their receptors leads to the formation of complexes and the transduction of signals to the canonical Smad signaling pathway (for example, BMP ligands, receptors, and Smads) and the non-canonical Smad signaling pathway (for example, MAPKs, p38, Erk, JNK, and PI3K/Akt) to regulate dental mesenchymal stem cell/progenitor proliferation and differentiation during dentin development and homeostasis. Both the canonical Smad and non-canonical Smad signaling pathways converge at transcription factors, such as Dlx3, Osx, Runx2, and others, to promote the differentiation of dental pulp mesenchymal cells into odontoblasts and downregulated gene expressions, such as those of DSPP and DMP1. Dysregulated BMP signaling causes a number of tooth disorders in humans. Mutation or knockout of BMP signaling-associated genes in mice results in dentin defects which enable a better understanding of the BMP signaling networks underlying odontoblast differentiation and dentin formation. This review summarizes the recent advances in our understanding of BMP signaling in odontoblast differentiation and dentin formation. It includes discussion of the expression of BMPs, their receptors, and the implicated downstream genes during dentinogenesis. In addition, the structures of BMPs, BMP receptors, antagonists, and dysregulation of BMP signaling pathways associated with dentin defects are described.
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Zhang W, Li Y, Xu A, Ouyang Q, Wu L, Zhou D, Wu L, Zhang B, Zhao X, Wang Y, Wang X, Duan W, Wang Q, You H, Huang J, Ou X, Jia J. Identification of novel non-HFE mutations in Chinese patients with hereditary hemochromatosis. Orphanet J Rare Dis 2022; 17:216. [PMID: 35668470 PMCID: PMC9169345 DOI: 10.1186/s13023-022-02349-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 04/26/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUNDS Hereditary hemochromatosis (HH) is mainly caused by homozygous p.C282Y mutations in HFE in the Caucasians. We recently reported non-HFE mutations constitute the major cause of HH in Chinese. However, there is still a relatively high proportion of cases with primary iron overload from unexplained causes. We aimed to explore novel non-HFE mutations in Chinese patients with primary iron overload. METHODS Whole exome sequence was conducted to screen mutations in novel HH-related genes in the 9 cases with unexplained primary iron overload. Then the representative candidate genes were screened for mutations in another cohort of 18 HH cases. The biological function of the selected genes and variants were analyzed in vitro. RESULTS Whole exome sequencing of 9 cases with unexplained primary iron overload identified 42 missense variants in 40 genes associated with iron metabolism pathway genes such as UBE2O p.K689R and PCSK7 p.R711W. Subsequent Sanger sequencing of the UBE2O and PCSK7 genes in the 27 cases with primary iron overload identified p.K689R in UBE2O, p.R711W and p.V143F in PCSK7 at frequency of 2/27,1/27 and 2/27 respectively. In vitro siRNA interference of UBE2O and PCSK7 resulted in down-regulated HAMP mRNA expression. Adenovirus generation of UBE2O p.K689R in cell lines resulted in increased expression of SMAD6 and SMAD7 and downregulation of p-SMAD1/5 and HAMP expression, and the reduction of hepcidin level. CONCLUSIONS Our study identified a series of novel candidate non-HFE mutations in Chinese patients with HH. These may provide insights into the genetic basis of unexplained primary iron overload.
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Affiliation(s)
- Wei Zhang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Yanmeng Li
- National Clinical Research Center for Digestive Diseases, Beijing, 100050, China.,Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Anjian Xu
- National Clinical Research Center for Digestive Diseases, Beijing, 100050, China.,Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Qin Ouyang
- National Clinical Research Center for Digestive Diseases, Beijing, 100050, China.,Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Liyan Wu
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Donghu Zhou
- National Clinical Research Center for Digestive Diseases, Beijing, 100050, China.,Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Lina Wu
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Bei Zhang
- National Clinical Research Center for Digestive Diseases, Beijing, 100050, China.,Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Xinyan Zhao
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Yu Wang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Xiaoming Wang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Weijia Duan
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Qianyi Wang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Hong You
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China.,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China
| | - Jian Huang
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China. .,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China. .,Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China.
| | - Xiaojuan Ou
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China. .,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China.
| | - Jidong Jia
- Liver Research Center, Beijing Friendship Hospital, Capital Medical University; Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, 95 Yong-An Road, Beijing, 100050, China. .,National Clinical Research Center for Digestive Diseases, Beijing, 100050, China.
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10
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Girelli D, Busti F, Brissot P, Cabantchik I, Muckenthaler MU, Porto G. Hemochromatosis classification: update and recommendations by the BIOIRON Society. Blood 2022; 139:3018-3029. [PMID: 34601591 PMCID: PMC11022970 DOI: 10.1182/blood.2021011338] [Citation(s) in RCA: 53] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2021] [Accepted: 09/05/2021] [Indexed: 12/15/2022] Open
Abstract
Hemochromatosis (HC) is a genetically heterogeneous disorder in which uncontrolled intestinal iron absorption may lead to progressive iron overload (IO) responsible for disabling and life-threatening complications such as arthritis, diabetes, heart failure, hepatic cirrhosis, and hepatocellular carcinoma. The recent advances in the knowledge of pathophysiology and molecular basis of iron metabolism have highlighted that HC is caused by mutations in at least 5 genes, resulting in insufficient hepcidin production or, rarely, resistance to hepcidin action. This has led to an HC classification based on different molecular subtypes, mainly reflecting successive gene discovery. This scheme was difficult to adopt in clinical practice and therefore needs revision. Here we present recommendations for unambiguous HC classification developed by a working group of the International Society for the Study of Iron in Biology and Medicine (BIOIRON Society), including both clinicians and basic scientists during a meeting in Heidelberg, Germany. We propose to deemphasize the use of the molecular subtype criteria in favor of a classification addressing both clinical issues and molecular complexity. Ferroportin disease (former type 4a) has been excluded because of its distinct phenotype. The novel classification aims to be of practical help whenever a detailed molecular characterization of HC is not readily available.
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Affiliation(s)
- Domenico Girelli
- Department of Medicine, Section of Internal Medicine, EuroBloodNet Center, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Fabiana Busti
- Department of Medicine, Section of Internal Medicine, EuroBloodNet Center, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
| | - Pierre Brissot
- INSERM, Univ-Rennes, Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1241, Institut NuMeCan, Rennes, France
| | - Ioav Cabantchik
- Alexander Silberman Institute of Life Sciences, Hebrew University, Jerusalem, Israel
| | - Martina U. Muckenthaler
- Department of Pediatric Oncology, Hematology, and Immunology and Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Translational Lung Research Center, German Center for Lung Research, Heidelberg, Germany
- German Centre for Cardiovascular Research, Partner Site Heidelberg, Mannheim, Germany
| | - Graça Porto
- Institute for Molecular and Cell Biology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Clinical Hematology, Santo António Hospital, Porto University, Porto, Portugal
| | - on behalf of the Nomenclature Committee of the International Society for the Study of Iron in Biology and Medicine (BIOIRON Society)
- Department of Medicine, Section of Internal Medicine, EuroBloodNet Center, University of Verona and Azienda Ospedaliera Universitaria Integrata Verona, Verona, Italy
- INSERM, Univ-Rennes, Institut National de la Recherche Agronomique, Unité Mixte de Recherche 1241, Institut NuMeCan, Rennes, France
- Alexander Silberman Institute of Life Sciences, Hebrew University, Jerusalem, Israel
- Department of Pediatric Oncology, Hematology, and Immunology and Molecular Medicine Partnership Unit, University of Heidelberg, Heidelberg, Germany
- Molecular Medicine Partnership Unit, European Molecular Biology Laboratory, Heidelberg, Germany
- Translational Lung Research Center, German Center for Lung Research, Heidelberg, Germany
- German Centre for Cardiovascular Research, Partner Site Heidelberg, Mannheim, Germany
- Institute for Molecular and Cell Biology, Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal
- Clinical Hematology, Santo António Hospital, Porto University, Porto, Portugal
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11
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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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Ravasi G, Pelucchi S, Bertola F, Capelletti MM, Mariani R, Piperno A. Identification of Novel Mutations by Targeted NGS Panel in Patients with Hyperferritinemia. Genes (Basel) 2021; 12:genes12111778. [PMID: 34828384 PMCID: PMC8623017 DOI: 10.3390/genes12111778] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/03/2021] [Accepted: 11/06/2021] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Several inherited diseases cause hyperferritinemia with or without iron overload. Differential diagnosis is complex and requires an extensive work-up. Currently, a clinical-guided approach to genetic tests is performed based on gene-by-gene sequencing. Although reasonable, this approach is expensive and time-consuming and Next Generation Sequencing (NGS) technology may provide cheaper and quicker large-scale DNA sequencing. METHODS We analysed 36 patients with non-HFE-related hyperferritinemia. Liver iron concentration was measured in 33 by magnetic resonance. A panel of 25 iron related genes was designed using SureDesign software. Custom libraries were generated and then sequenced using Ion Torrent PGM. RESULTS We identified six novel mutations in SLC40A1, three novel and one known mutation in TFR2, one known mutation and a de-novo deletion in HJV, and a novel mutation in HAMP in ten patients. In silico analyses supported the pathogenic role of the mutations. CONCLUSIONS Our results support the use of an NGS-based panel in selected patients with hyperferritinemia in a tertiary center for iron metabolism disorders. However, 26 out of 36 patients did not show genetic variants that can individually explain hyperferritinemia and/or iron overload suggesting the existence of other genetic defects or gene-gene and gene-environment interactions needing further studies.
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Affiliation(s)
- Giulia Ravasi
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.R.); (S.P.); (M.M.C.)
| | - Sara Pelucchi
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.R.); (S.P.); (M.M.C.)
| | - Francesca Bertola
- Medical Genetics, S. Gerardo Hospital, ASST-Monza, 20900 Monza, Italy;
| | - Martina Maria Capelletti
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.R.); (S.P.); (M.M.C.)
| | - Raffaella Mariani
- Disorders of Iron Metabolism, Centre for Rare Diseases, San Gerardo Hospital, ASST-Monza, 20900 Monza, Italy;
| | - Alberto Piperno
- Department of Medicine and Surgery, University of Milano-Bicocca, 20900 Monza, Italy; (G.R.); (S.P.); (M.M.C.)
- Medical Genetics, S. Gerardo Hospital, ASST-Monza, 20900 Monza, Italy;
- Disorders of Iron Metabolism, Centre for Rare Diseases, San Gerardo Hospital, ASST-Monza, 20900 Monza, Italy;
- Correspondence: ; Tel.: +39-03-9233-3461
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13
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Baas FS, Rishi G, Swinkels DW, Subramaniam VN. Genetic Diagnosis in Hereditary Hemochromatosis: Discovering and Understanding the Biological Relevance of Variants. Clin Chem 2021; 67:1324-1341. [PMID: 34402502 DOI: 10.1093/clinchem/hvab130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2021] [Accepted: 06/23/2021] [Indexed: 11/13/2022]
Abstract
BACKGROUND Hereditary hemochromatosis (HH) is a genetic disease, leading to iron accumulation and possible organ damage. Patients are usually homozygous for p. Cys282Tyr in the homeostatic iron regulator gene but may have mutations in other genes involved in the regulation of iron. Next-generation sequencing is increasingly being utilized for the diagnosis of patients, leading to the discovery of novel genetic variants. The clinical significance of these variants is often unknown. CONTENT Determining the pathogenicity of such variants of unknown significance is important for diagnostics and genetic counseling. Predictions can be made using in silico computational tools and population data, but additional evidence is required for a conclusive pathogenicity classification. Genetic disease models, such as in vitro models using cellular overexpression, induced pluripotent stem cells or organoids, and in vivo models using mice or zebrafish all have their own challenges and opportunities when used to model HH and other iron disorders. Recent developments in gene-editing technologies are transforming the field of genetic disease modeling. SUMMARY In summary, this review addresses methods and developments regarding the discovery and classification of genetic variants, from in silico tools to in vitro and in vivo models, and presents them in the context of HH. It also explores recent gene-editing developments and how they can be applied to the discussed models of genetic disease.
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Affiliation(s)
- Floor S Baas
- Translational Metabolic Laboratory (TML 831), Radboudumc, Nijmegen, the Netherlands.,Hepatogenomics Research Group, School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Gautam Rishi
- Hepatogenomics Research Group, School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia
| | - Dorine W Swinkels
- Translational Metabolic Laboratory (TML 831), Radboudumc, Nijmegen, the Netherlands
| | - V Nathan Subramaniam
- Hepatogenomics Research Group, School of Biomedical Sciences, Queensland University of Technology (QUT), Brisbane, QLD, Australia
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Pauk M, Kufner V, Rumenovic V, Dumic-Cule I, Farkas V, Milosevic M, Bordukalo-Niksic T, Vukicevic S. Iron overload in aging Bmp6‑/‑ mice induces exocrine pancreatic injury and fibrosis due to acinar cell loss. Int J Mol Med 2021; 47:60. [PMID: 33649802 PMCID: PMC7910010 DOI: 10.3892/ijmm.2021.4893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Accepted: 01/19/2021] [Indexed: 11/27/2022] Open
Abstract
The relationship between hemochromatosis and diabetes has been well established, as excessive iron deposition has been reported to result in impaired function of the endocrine and exocrine pancreas. Therefore, the objective of the present study was to analyze the effects of iron accumulation on the pancreata and glucose homeostasis in a bone morphogenetic protein 6-knockout (Bmp6−/−) mouse model of hemochromatosis. The sera and pancreatic tissues of wild-type (WT) and Bmp6−/− mice (age, 3 and 10 months) were subjected to biochemical and histological analyses. In addition, 18F-fluorodeoxyglucose biodistribution was evaluated in the liver, muscle, heart, kidney and adipose tissue of both animal groups. The results demonstrated that 3-month-old Bmp6−/− mice exhibited iron accumulation preferentially in the exocrine pancreas, with no signs of pancreatic injury or fibrosis. No changes were observed in the glucose metabolism, as pancreatic islet diameter, insulin and glucagon secretion, blood glucose levels and glucose uptake in the liver, muscle and adipose tissue remained comparable with those in the WT mice. Aging Bmp6−/− mice presented with progressive iron deposits in the exocrine pancreas, leading to pancreatic degeneration and injury that was characterized by acinar atrophy, fibrosis and the infiltration of inflammatory cells. However, the aging mice exhibited unaltered blood glucose levels and islet structure, normal insulin secretion and moderately increased α-cell mass compared with those in the age-matched WT mice. Additionally, iron overload and pancreatic damage were not observed in the aging WT mice. These results supported a pathogenic role of iron overload in aging Bmp6−/− mice leading to iron-induced exocrine pancreatic deficiency, whereas the endocrine pancreas retained normal function.
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Affiliation(s)
- Martina Pauk
- Laboratory for Mineralized Tissues, Center for Translational and Clinical Research, School of Medicine, University of Zagreb, HR‑10000 Zagreb, Croatia
| | - Vera Kufner
- Laboratory for Mineralized Tissues, Center for Translational and Clinical Research, School of Medicine, University of Zagreb, HR‑10000 Zagreb, Croatia
| | - Viktorija Rumenovic
- Laboratory for Mineralized Tissues, Center for Translational and Clinical Research, School of Medicine, University of Zagreb, HR‑10000 Zagreb, Croatia
| | - Ivo Dumic-Cule
- Laboratory for Mineralized Tissues, Center for Translational and Clinical Research, School of Medicine, University of Zagreb, HR‑10000 Zagreb, Croatia
| | - Vladimir Farkas
- Molecular Biology Department, Rudjer Boskovic Institute, HR‑10000 Zagreb, Croatia
| | - Milan Milosevic
- Andrija Stampar School of Public Health, School of Medicine, University of Zagreb, HR‑10000 Zagreb, Croatia
| | - Tatjana Bordukalo-Niksic
- Laboratory for Mineralized Tissues, Center for Translational and Clinical Research, School of Medicine, University of Zagreb, HR‑10000 Zagreb, Croatia
| | - Slobodan Vukicevic
- Laboratory for Mineralized Tissues, Center for Translational and Clinical Research, School of Medicine, University of Zagreb, HR‑10000 Zagreb, Croatia
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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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17
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Adams PC, Horgan-Bell C, Walsh S, Sadikovic B. Porphyria cutanea tarda associated with elevated serum ferritin, iron overload, and a bone morphogenetic protein 6 genetic variant. CANADIAN LIVER JOURNAL 2020; 3:232-234. [PMID: 35991856 PMCID: PMC9202784 DOI: 10.3138/canlivj-2019-0018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 08/04/2019] [Indexed: 08/27/2023]
Abstract
A man aged 51 years was referred to dermatology for hand dermatitis. The dorsal hands and fingers had superficial erosions with pale pink shallow scars and milia suggestive of porphyria cutanea tarda (PCT). Urine and fecal studies were typical of PCT. The patient had daily alcohol use and was found to have elevated serum ferritin, aspartate aminotransferase, and alanine transaminase. Genetic testing for common hemochromatosis genetic variants (HFE C282Y and H63D) was normal. He underwent next-generation sequencing analysis using the 16-gene hyperferritinemia gene panel for genes known to be associated with hereditary hyperferritinemia, iron overload, or both and was discovered to have a genetic variant in bone morphogenetic 6 (BMP6, c.287T> C, p.Leu96Pro). The skin lesions improved with phlebotomy therapy.
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Affiliation(s)
- Paul C Adams
- Department of Medicine, University Hospital, Western University, London, Ontario, Canada
| | | | - Scott Walsh
- Division of Dermatology, University of Toronto, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada
| | - Bekim Sadikovic
- Department of Pathology and Laboratory Medicine, Western University, London, Ontario, and Molecular Genetics Laboratory, Molecular Diagnostics Division, London Health Sciences Centre, London, Ontario, Canada
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18
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Alvarenga AM, da Silva NK, Fonseca PFS, Oliveira TGM, da Silva Monteiro JB, Cançado RD, Naoum FA, Dinardo CL, Brissot P, Santos PCJL. Novel mutations in the bone morphogenetic protein 6 gene in patients with iron overload and non-homozygous genotype for the HFE p.Cys282Tyr mutation. Blood Cells Mol Dis 2020; 84:102444. [PMID: 32464486 DOI: 10.1016/j.bcmd.2020.102444] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2020] [Revised: 05/03/2020] [Accepted: 05/04/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND Five main genes are associated with hemochromatosis; however, current studies show that, in addition to these genes, others may be associated with primary iron overload (IO). One of these is the bone morphogenetic protein 6 (BMP6), which encodes a protein that modulates hepcidin synthesis and, consequently, iron homeostasis. AIM To identify BMP6 gene pathogenic variants in patients with IO and non-homozygous genotype for the HFE p.Cys282Tyr mutation. MATERIALS AND METHODS Fifty-three patients with primary IO and non-homozygous genotype for the HFE p.Cys282Tyr were selected. Subsequent bidirectional DNA sequencing of BMP6 exons was performed. RESULTS Two novel variants were found. One at homozygous state p.Gln158Ter (c.472C>T) was pathogenic, the other one at heterozygous state p.Val394Met (c.1180G>A) was of uncertain significance (VUS); the third variant at heterozygous state p.Arg257His (c.770G>A) has already been described and associated with IO. No BMP6 pathogenic variants that would explain iron overload phenotypes were detected in 94% of the studied patients. CONCLUSION Identification of the BMP6 pathogenic variants in Brazilian patients with primary IO might contribute to the genetic understanding of this phenotype.
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Affiliation(s)
- Aline Morgan Alvarenga
- Department of Pharmacology - Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-Unifesp), São Paulo, Brazil.
| | - Nathália Kozikas da Silva
- Department of Pharmacology - Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-Unifesp), São Paulo, Brazil.
| | - Paula Fernanda Silva Fonseca
- Department of Pharmacology - Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-Unifesp), São Paulo, Brazil.
| | - Theo G M Oliveira
- Laboratory of Genetics and Molecular Cardiology, Heart Institute (InCor), University of São Paulo Medical School, São Paulo, Brazil.
| | | | | | | | - Carla Luana Dinardo
- Fundação Pró-Sangue, Hemocentro de São Paulo, São Paulo, SP, Brazil; Universidade de São Paulo (USP), São Paulo, SP, Brazil.
| | - Pierre Brissot
- Institut NuMeCan, Inserm U-1241, Univ Rennes 1, Rennes, France.
| | - Paulo Caleb Junior Lima Santos
- Department of Pharmacology - Escola Paulista de Medicina, Universidade Federal de São Paulo (EPM-Unifesp), São Paulo, Brazil.
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19
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Vila Cuenca M, Marchi G, Barqué A, Esteban-Jurado C, Marchetto A, Giorgetti A, Chelban V, Houlden H, Wood NW, Piubelli C, Dorigatti Borges M, Martins de Albuquerque D, Yotsumoto Fertrin K, Jové-Buxeda E, Sanchez-Delgado J, Baena-Díez N, Burnyte B, Utkus A, Busti F, Kaubrys G, Suku E, Kowalczyk K, Karaszewski B, Porter JB, Pollard S, Eleftheriou P, Bignell P, Girelli D, Sanchez M. Genetic and Clinical Heterogeneity in Thirteen New Cases with Aceruloplasminemia. Atypical Anemia as a Clue for an Early Diagnosis. Int J Mol Sci 2020; 21:E2374. [PMID: 32235485 PMCID: PMC7178074 DOI: 10.3390/ijms21072374] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 03/26/2020] [Indexed: 12/11/2022] Open
Abstract
Aceruloplasminemia is a rare autosomal recessive genetic disease characterized by mild microcytic anemia, diabetes, retinopathy, liver disease, and progressive neurological symptoms due to iron accumulation in pancreas, retina, liver, and brain. The disease is caused by mutations in the Ceruloplasmin (CP) gene that produce a strong reduction or absence of ceruloplasmin ferroxidase activity, leading to an impairment of iron metabolism. Most patients described so far are from Japan. Prompt diagnosis and therapy are crucial to prevent neurological complications since, once established, they are usually irreversible. Here, we describe the largest series of non-Japanese patients with aceruloplasminemia published so far, including 13 individuals from 11 families carrying 13 mutations in the CP gene (7 missense, 3 frameshifts, and 3 splicing mutations), 10 of which are novel. All missense mutations were studied by computational modeling. Clinical manifestations were heterogeneous, but anemia, often but not necessarily microcytic, was frequently the earliest one. This study confirms the clinical and genetic heterogeneity of aceruloplasminemia, a disease expected to be increasingly diagnosed in the Next-Generation Sequencing (NGS) era. Unexplained anemia with low transferrin saturation and high ferritin levels without inflammation should prompt the suspicion of aceruloplasminemia, which can be easily confirmed by low serum ceruloplasmin levels. Collaborative joint efforts are needed to better understand the pathophysiology of this potentially disabling disease.
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Affiliation(s)
- Marc Vila Cuenca
- Iron Metabolism: Regulation and Diseases Group, Josep Carreras Leukaemia Research Institute (IJC), Campus Can Ruti, Badalona, 08916 Barcelona, Spain; (M.V.C.); (A.B.); (C.E.-J.)
| | - Giacomo Marchi
- EuroBloodNet Referral Center for Iron Disorders and Gruppo Interdisciplinare Malattie del Ferro, Internal Medicine Unit, Azienda Ospedaliera Universitaria Integrata di Verona, 37134 Verona, Italy; (G.M.); (F.B.)
| | - Anna Barqué
- Iron Metabolism: Regulation and Diseases Group, Josep Carreras Leukaemia Research Institute (IJC), Campus Can Ruti, Badalona, 08916 Barcelona, Spain; (M.V.C.); (A.B.); (C.E.-J.)
| | - Clara Esteban-Jurado
- Iron Metabolism: Regulation and Diseases Group, Josep Carreras Leukaemia Research Institute (IJC), Campus Can Ruti, Badalona, 08916 Barcelona, Spain; (M.V.C.); (A.B.); (C.E.-J.)
| | - Alessandro Marchetto
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (A.M.); (A.G.); (E.S.)
| | - Alejandro Giorgetti
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (A.M.); (A.G.); (E.S.)
| | - Viorica Chelban
- National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK; (V.C.); (H.H.); (N.W.W.)
- Department of Neuromuscular Diseases, Institute of Neurology, University College London, London WC1N 3BG, UK
- Department of Neurology and Neurosurgery, Institute of Emergency Medicine, Toma Ciorbă 1, Chisinau, MD-2052 Chisinau, Republic of Moldova
| | - Henry Houlden
- National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK; (V.C.); (H.H.); (N.W.W.)
- Department of Neuromuscular Diseases, Institute of Neurology, University College London, London WC1N 3BG, UK
- Neurogenetics Laboratory, The National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
| | - Nicholas W Wood
- National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK; (V.C.); (H.H.); (N.W.W.)
- Neurogenetics Laboratory, The National Hospital for Neurology and Neurosurgery, London WC1N 3BG, UK
| | - Chiara Piubelli
- Centre for Tropical Diseases, Ospedale Sacro Cuore - Don Calabria, 37024 Negrar (VR), Italy;
| | - Marina Dorigatti Borges
- Hematology and Hemotherapy Center—Hemocentro Campinas, University of Campinas—UNICAMP, Campinas 13083-878, Brazil; (M.D.B.); (D.M.d.A.); (K.Y.F.)
| | - Dulcinéia Martins de Albuquerque
- Hematology and Hemotherapy Center—Hemocentro Campinas, University of Campinas—UNICAMP, Campinas 13083-878, Brazil; (M.D.B.); (D.M.d.A.); (K.Y.F.)
| | - Kleber Yotsumoto Fertrin
- Hematology and Hemotherapy Center—Hemocentro Campinas, University of Campinas—UNICAMP, Campinas 13083-878, Brazil; (M.D.B.); (D.M.d.A.); (K.Y.F.)
- Division of Hematology, Department of Medicine, University of Washington, Seattle, WA 98195, USA
| | - Ester Jové-Buxeda
- Internal Medicine Department, Parc Tauli Hospital Universitari, Institut d’ Investigació i Innovació Parc Tauli I3PT, Universidad Autonoma de Barcelona, 08208 Sabadell, Spain;
| | - Jordi Sanchez-Delgado
- Hepatology Unit, Digestive Diseases Department, Parc Tauli Hospital Universitari. Institut d’ Investigació i Innovació Parc Tauli I3PT, Universidad Autonoma de Barcelona, 08208 Sabadell, Spain;
- Centro de Investigación Biomedica y en red Enfermedades hepáticas y digestivas (CIBERehd), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Neus Baena-Díez
- Genetic Department, Parc Tauli Hospital Universitari, Institut d’ Investigació i Innovació Parc Tauli I3PT, Universidad Autonoma de Barcelona, 08208 Sabadell, Spain;
| | - Birute Burnyte
- Department of Human and Medical Genetics, Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, LT-08661 Vilnius, Lithuania; (B.B.); (A.U.)
| | - Algirdas Utkus
- Department of Human and Medical Genetics, Institute of Biomedical Sciences, Faculty of Medicine, Vilnius University, LT-08661 Vilnius, Lithuania; (B.B.); (A.U.)
| | - Fabiana Busti
- EuroBloodNet Referral Center for Iron Disorders and Gruppo Interdisciplinare Malattie del Ferro, Internal Medicine Unit, Azienda Ospedaliera Universitaria Integrata di Verona, 37134 Verona, Italy; (G.M.); (F.B.)
| | - Gintaras Kaubrys
- Clinic of Neurology and Neurosurgery, Institute of Clinical Medicine, Faculty of Medicine, Vilnius University, 08661 Vilnius, Lithuania;
| | - Eda Suku
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (A.M.); (A.G.); (E.S.)
| | - Kamil Kowalczyk
- Department of Adult Neurology, Medical University of Gdańsk, 80-210 Gdańsk, Poland; (K.K.); (B.K.)
| | - Bartosz Karaszewski
- Department of Adult Neurology, Medical University of Gdańsk, 80-210 Gdańsk, Poland; (K.K.); (B.K.)
| | - John B. Porter
- Joint Red Cell Unit, Haematology Department, University College London NHS Foundation Trust, Cancer Services, 250 Euston Road, London NW1 2PG, UK; (J.B.P.); (P.E.)
| | - Sally Pollard
- Consultant Paediatrician, Bradford Royal Infirmary, Duckworthlane, Bradford BD9 6RJ, UK;
| | - Perla Eleftheriou
- Joint Red Cell Unit, Haematology Department, University College London NHS Foundation Trust, Cancer Services, 250 Euston Road, London NW1 2PG, UK; (J.B.P.); (P.E.)
| | - Patricia Bignell
- Oxford Regional Genetics Laboratory, Oxford University Hospitals NHS Foundation Trust, The Churchill Hospital, Oxford OX3 7LE, UK;
| | - Domenico Girelli
- EuroBloodNet Referral Center for Iron Disorders and Gruppo Interdisciplinare Malattie del Ferro, Internal Medicine Unit, Azienda Ospedaliera Universitaria Integrata di Verona, 37134 Verona, Italy; (G.M.); (F.B.)
| | - Mayka Sanchez
- Iron Metabolism: Regulation and Diseases Group, Department of Basic Sciences, Faculty of Medicine and Health Sciences, Universitat Internacional de Catalunya (UIC); Sant Cugat del Valles, 08017 Barcelona, Spain
- Program of Program of Predictive and Personalized Medicine of Cancer (PMPPC), Institut d ‘Investigació Germans Trias i Pujol (IGTP), Campus Can Ruti, Badalona, 08916 Barcelona, Spain
- BloodGenetics S.L., Esplugues de Llobregat, 08950 Barcelona, Spain
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Rametta R, Dongiovanni P, Baselli GA, Pelusi S, Meroni M, Fracanzani AL, Busti F, Castagna A, Scarlini S, Corradini E, Pietrangelo A, Girelli D, Fargion S, Valenti L. Impact of natural neuromedin-B receptor variants on iron metabolism. Am J Hematol 2020; 95:167-177. [PMID: 31724192 DOI: 10.1002/ajh.25679] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 10/18/2019] [Accepted: 11/11/2019] [Indexed: 12/27/2022]
Abstract
Iron overload heritability remains partly unexplained. By performing whole exome sequencing in three patients with a clinical phenotype of hemochromatosis not accounted by known genetic risk factors, we identified in all patients rare variants predicted to alter activity of Neuromedin-B receptor (NMBR). Coding NMBR mutations were enriched in 129 patients with hereditary hemochromatosis or iron overload phenotype, as compared to ethnically matched controls, including 100 local healthy blood donors and 1000Genomes project participants (15.5% vs 5%, P = .0038 at burden test), and were associated with higher transferrin saturation in regular blood donors (P = .04). Consistently, in 191 patients with nonalcoholic fatty liver, the most common low-frequency p.L390 M variant was independently associated with higher ferritin (P = .03). In 58 individuals, who underwent oral iron challenge, carriage of the p.L390 M variant was associated with higher transferrin saturation and lower hepcidin release. Furthermore, the circulating concentration of the natural NMBR ligand, Neuromedin-B, was reduced in response to iron challenge. It was also decreased in individuals carrying the p.L390 M variant and with hemochromatosis in parallel with increased transferrin saturation. In mice, Nmbr was induced by chronic dietary iron overload in the liver, gut, pancreas, spleen, and skeletal muscle, while Nmb was downregulated in gut, pancreas and spleen. Finally, Nmb amplified holo-transferrin dependent induction of hepcidin in primary mouse hepatocytes, which was associated with Jak2 induction and abolished by the NMBR antagonist PD168368. In conclusion, NMBR natural variants were enriched in patients with iron overload, and associated with facilitated iron absorption, possibly related to a defect of iron-induced hepcidin release.
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Affiliation(s)
- Raffaela Rametta
- General Medicine and Metabolic DiseasesFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
| | - Paola Dongiovanni
- General Medicine and Metabolic DiseasesFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
| | - Guido A. Baselli
- Department of Pathophysiology and TransplantationUniversità degli Studi di Milano Milan Italy
| | - Serena Pelusi
- Department of Pathophysiology and TransplantationUniversità degli Studi di Milano Milan Italy
- Translational Medicine – Department of Transfusion Medicine and HematologyFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
| | - Marica Meroni
- General Medicine and Metabolic DiseasesFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
| | - Anna L. Fracanzani
- General Medicine and Metabolic DiseasesFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
- Department of Pathophysiology and TransplantationUniversità degli Studi di Milano Milan Italy
| | - Fabiana Busti
- Department of MedicineSection of Internal Medicine, Azienda Ospedaliera Universitaria Integrata Verona, University of Verona Verona Italy
| | - Annalisa Castagna
- Department of MedicineSection of Internal Medicine, Azienda Ospedaliera Universitaria Integrata Verona, University of Verona Verona Italy
| | - Stefania Scarlini
- Internal Medicine and Center for Hemochromatosis and Heredometabolic Liver DiseasesAzienda Ospedaliera Universitaria di Modena, University of Modena and Reggio Emilia Modena Italy
| | - Elena Corradini
- Internal Medicine and Center for Hemochromatosis and Heredometabolic Liver DiseasesAzienda Ospedaliera Universitaria di Modena, University of Modena and Reggio Emilia Modena Italy
| | - Antonello Pietrangelo
- Internal Medicine and Center for Hemochromatosis and Heredometabolic Liver DiseasesAzienda Ospedaliera Universitaria di Modena, University of Modena and Reggio Emilia Modena Italy
| | - Domenico Girelli
- Department of MedicineSection of Internal Medicine, Azienda Ospedaliera Universitaria Integrata Verona, University of Verona Verona Italy
| | - Silvia Fargion
- General Medicine and Metabolic DiseasesFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
- Department of Pathophysiology and TransplantationUniversità degli Studi di Milano Milan Italy
| | - Luca Valenti
- Department of Pathophysiology and TransplantationUniversità degli Studi di Milano Milan Italy
- Translational Medicine – Department of Transfusion Medicine and HematologyFondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico Milan Italy
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21
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Daher R, Lefebvre T, Puy H, Karim Z. Extrahepatic hepcidin production: The intriguing outcomes of recent years. World J Clin Cases 2019; 7:1926-1936. [PMID: 31423425 PMCID: PMC6695539 DOI: 10.12998/wjcc.v7.i15.1926] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/18/2019] [Accepted: 06/27/2019] [Indexed: 02/05/2023] Open
Abstract
Hepcidin is the hyposideremic hormone regulating iron metabolism. It is a defensin-like disulfide-bonded peptide with antimicrobial activity. The main site of hepcidin production is the liver where its synthesis is modulated by iron, inflammation and erythropoietic signaling. However, hepcidin locally produced in several peripheral organs seems to be an important actor for the maintenance of iron homeostasis in these organs. This review highlights the presence of peripheral hepcidin and its potential functions. Understanding the role of extrahepatic hepcidin could be of great physiological and therapeutic importance for several specific pathologies.
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Affiliation(s)
- Raêd Daher
- Université Paris Diderot, Bichat site, Paris 75018, France
- Inflammation Research Center (CRI), INSERM U1149/ERL CNRS 8252, Paris 75018, France
- Laboratory of Excellence, GR-Ex, Paris 75018, France
| | - Thibaud Lefebvre
- Université Paris Diderot, Bichat site, Paris 75018, France
- Inflammation Research Center (CRI), INSERM U1149/ERL CNRS 8252, Paris 75018, France
- Laboratory of Excellence, GR-Ex, Paris 75018, France
| | - Hervé Puy
- Université Paris Diderot, Bichat site, Paris 75018, France
- Inflammation Research Center (CRI), INSERM U1149/ERL CNRS 8252, Paris 75018, France
- Laboratory of Excellence, GR-Ex, Paris 75018, France
| | - Zoubida Karim
- Université Paris Diderot, Bichat site, Paris 75018, France
- Inflammation Research Center (CRI), INSERM U1149/ERL CNRS 8252, Paris 75018, France
- Laboratory of Excellence, GR-Ex, Paris 75018, France
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22
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Abstract
The liver orchestrates systemic iron balance by producing and secreting hepcidin. Known as the iron hormone, hepcidin induces degradation of the iron exporter ferroportin to control iron entry into the bloodstream from dietary sources, iron recycling macrophages, and body stores. Under physiologic conditions, hepcidin production is reduced by iron deficiency and erythropoietic drive to increase the iron supply when needed to support red blood cell production and other essential functions. Conversely, hepcidin production is induced by iron loading and inflammation to prevent the toxicity of iron excess and limit its availability to pathogens. The inability to appropriately regulate hepcidin production in response to these physiologic cues underlies genetic disorders of iron overload and deficiency, including hereditary hemochromatosis and iron-refractory iron deficiency anemia. Moreover, excess hepcidin suppression in the setting of ineffective erythropoiesis contributes to iron-loading anemias such as β-thalassemia, whereas excess hepcidin induction contributes to iron-restricted erythropoiesis and anemia in chronic inflammatory diseases. These diseases have provided key insights into understanding the mechanisms by which the liver senses plasma and tissue iron levels, the iron demand of erythrocyte precursors, and the presence of potential pathogens and, importantly, how these various signals are integrated to appropriately regulate hepcidin production. This review will focus on recent insights into how the liver senses body iron levels and coordinates this with other signals to regulate hepcidin production and systemic iron homeostasis.
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23
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Abstract
Dietary iron absorption and systemic iron traffic are tightly controlled by hepcidin, a liver-derived peptide hormone. Hepcidin inhibits iron entry into plasma by binding to and inactivating the iron exporter ferroportin in target cells, such as duodenal enterocytes and tissue macrophages. Hepcidin is induced in response to increased body iron stores to inhibit further iron absorption and prevent iron overload. The mechanism involves the BMP/SMAD signaling pathway, which triggers transcriptional hepcidin induction. Inactivating mutations in components of this pathway cause hepcidin deficiency, which allows inappropriately increased iron absorption and efflux into the bloodstream. This leads to hereditary hemochromatosis (HH), a genetically heterogenous autosomal recessive disorder of iron metabolism characterized by gradual buildup of unshielded non-transferrin bound iron (NTBI) in plasma and excessive iron deposition in tissue parenchymal cells. The predominant HH form is linked to mutations in the HFE gene and constitutes the most frequent genetic disorder in Caucasians. Other, more severe and rare variants are caused by inactivating mutations in HJV (hemojuvelin), HAMP (hepcidin) or TFR2 (transferrin receptor 2). Mutations in SLC40A1 (ferroportin) that cause hepcidin resistance recapitulate the biochemical phenotype of HH. However, ferroportin-related hemochromatosis is transmitted in an autosomal dominant manner. Loss-of-function ferroportin mutations lead to ferroportin disease, characterized by iron overload in macrophages and low transferrin saturation. Aceruloplasminemia and atransferrinemia are further inherited disorders of iron overload caused by deficiency in ceruloplasmin or transferrin, the plasma ferroxidase and iron carrier, respectively.
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Affiliation(s)
- Kostas Pantopoulos
- Lady Davis Institute for Medical Research, Jewish General Hospital, Montreal, QC, Canada.,Department of Medicine, McGill University, Montreal, QC, Canada
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24
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Lv T, Zhang W, Xu A, Li Y, Zhou D, Zhang B, Li X, Zhao X, Wang Y, Wang X, Duan W, Wang Q, Xu H, Zheng J, Zhao R, Zhu L, Dong Y, Lu L, Chen Y, Long J, Zheng S, Wang W, You H, Jia J, Ou X, Huang J. Non- HFE mutations in haemochromatosis in China: combination of heterozygous mutations involving HJV signal peptide variants. J Med Genet 2018; 55:650-660. [PMID: 30166352 DOI: 10.1136/jmedgenet-2018-105348] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 06/22/2018] [Accepted: 07/08/2018] [Indexed: 11/04/2022]
Abstract
INTRODUCTION Hereditary haemochromatosis (HH) caused by a homozygous p.C282Y mutation in haemochromatosis (HFE) gene has been well documented. However, less is known about the causative non-HFE mutation. We aimed to assess mutation patterns of haemochromatosis-related genes in Chinese patients with primary iron overload. METHODS Patients were preanalysed for mutations in the classic HH-related genes: HFE, HJV, HAMP, TFR2 and SLC40A1. Whole exome sequencing was conducted for cases with variants in HJV signal peptide region. Representative variants were analysed for biological function. RESULTS None of the cases analysed harboured the HFE p.C282Y; however, 21 of 22 primary iron-overload cases harboured at least one non-synonymous variant in the non-HFE genes. Specifically, p.E3D or p.Q6H variants in the HJV signal peptide region were identified in nine cases (40.9%). In two of three probands with the HJV p.E3D, exome sequencing identified accompanying variants in BMP/SMAD pathway genes, including TMPRSS6 p.T331M and BMP4 p.R269Q, and interestingly, SUGP2 p.R639Q was identified in all the three cases. Pedigree analysis showed a similar pattern of combination of heterozygous mutations in cases with HJV p.E3D or p.Q6H, with SUGP2 p.R639Q or HJV p.C321X being common mutation. In vitro siRNA interference of SUGP2 showed a novel role of downregulating the BMP/SMAD pathway. Site-directed mutagenesis of HJV p.Q6H/p.C321X in cell lines resulted in loss of membrane localisation of mutant HJV, and downregulation of p-SMAD1/5 and HAMP. CONCLUSION Compound heterozygous mutations of HJV or combined heterozygous mutations of BMP/SMAD pathway genes, marked by HJV variants in the signal peptide region, may represent a novel aetiological factor for HH.
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Affiliation(s)
- Tingxia Lv
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Wei Zhang
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Anjian Xu
- Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Yanmeng Li
- Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Donghu Zhou
- Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Bei Zhang
- Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Xiaojin Li
- Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Xinyan Zhao
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Yu Wang
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Xiaoming Wang
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Weijia Duan
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Qianyi Wang
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Hexiang Xu
- Department of Infectious Diseases, The Third Affiliated Hospital of Anhui Medical University, The First People's Hospital of Hefei, Hefei, China
| | - JiShun Zheng
- Department of Infectious Diseases, The Third Affiliated Hospital of Anhui Medical University, The First People's Hospital of Hefei, Hefei, China
| | - Rongrong Zhao
- Department of Infectious Diseases, The First Hospital of Lanzhou University, Lanzhou, China
| | - Longdong Zhu
- Department of Infectious Diseases, The First Hospital of Lanzhou University, Lanzhou, China
| | - Yuwei Dong
- Department of Gastroenterology, School of Medicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Lungen Lu
- Department of Gastroenterology, School of Medicine, Shanghai General Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yongpeng Chen
- Department of Infectious Diseases, Institute of Hepatology, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jiang Long
- Department of Oncology Minimally Invasive Interventional Radiology, Beijing You-An Hospital, Capital Medical University, Shanghai, China
| | - Sujun Zheng
- Artificial Liver Center, Beijing You-An Hospital, Capital Medical University, Beijing, China
| | - Wei Wang
- Department of Clinical Laboratory, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Hong You
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Jidong Jia
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Xiaojuan Ou
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
| | - Jian Huang
- Beijing Key Laboratory of Translational Medicine on Liver Cirrhosis, Liver Research Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Experimental Center, Beijing Friendship Hospital, Capital Medical University, Beijing, China.,Clinical Research Center for Rare Liver Disease, Capital Medical University, Beijing, China.,Liver Research Center, National Clinical Research Center for Digestive Diseases, Beijing, China
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25
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Chen L, Liu M, Luan Y, Liu Y, Zhang Z, Ma B, Liu X, Liu Y. BMP‑6 protects retinal pigment epithelial cells from oxidative stress‑induced injury by inhibiting the MAPK signaling pathways. Int J Mol Med 2018; 42:1096-1105. [PMID: 29767257 DOI: 10.3892/ijmm.2018.3675] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2017] [Accepted: 05/10/2018] [Indexed: 11/06/2022] Open
Abstract
Worldwide, neovascular age‑related macular degeneration (nAMD) is one of the most common causes of blindness in the elderly. In particular, degeneration of retinal pigment epithelial (RPE) cells represents the main pathological process in the development of nAMD, and oxidative stress serves a major role. The present study aimed to investigate the association between bone morphogenetic protein 6 (BMP‑6) and nAMD. BMP‑6 concentration was significantly reduced in patients with wet nAMD compared with in the control group. Furthermore, the present study investigated the protective effects of BMP‑6 on RPE cells following oxidative stress‑induced injury. Cell Counting Kit‑8 assay and terminal deoxynucleotidyl transferase dUTP nick‑end labeling staining demonstrated that BMP‑6 increased RPE cell viability, which was decreased following treatment with hydrogen peroxide (H2O2), and reduced H2O2‑induced apoptosis. In addition, western blotting revealed that BMP‑6 reversed the decrease in pro‑caspase‑3 levels and the dysregulation of the B‑cell lymphoma 2 (Bcl‑2)/Bcl‑2‑associated X protein (Bax) balance caused by H2O2. In addition, alterations in c‑Jun N‑terminal protein kinase (JNK) and p38 mitogen‑activated protein kinase (MAPK) expression were examined, and pretreatment with BMP‑6 was demonstrated to reduce H2O2‑induced activation of JNK and p38 MAPK. Conversely, the effects of BMP‑6 were attenuated by its inhibitor noggin. In conclusion, the present study demonstrated that BMP‑6 may protect RPE cells from oxidative stress injury to a certain extent, which may be associated with alterations in the MAPK signaling pathway. However, the specific mechanism of action underlying this effect requires further investigation. Overall, the present study laid a foundation for exploring novel nAMD treatment methods.
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Affiliation(s)
- Li Chen
- Department of Ophthalmology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Ming Liu
- Department of Ophthalmology, The First Hospital of Xi'an, Xi'an, Shaanxi 710002, P.R. China
| | - Yan Luan
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - Yingfei Liu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - Zhichao Zhang
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
| | - Bo Ma
- Department of Ophthalmology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Xuan Liu
- Department of Ophthalmology, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi 710061, P.R. China
| | - Yong Liu
- Institute of Neurobiology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, P.R. China
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26
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McDonald CJ, Rishi G, Secondes ES, Ostini L, Wallace DF, Crawford DHG, Sia H, Clark P, Subramaniam VN. Evaluation of a bone morphogenetic protein 6 variant as a cause of iron loading. Hum Genomics 2018; 12:23. [PMID: 29695288 PMCID: PMC5918843 DOI: 10.1186/s40246-018-0155-5] [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: 01/18/2018] [Accepted: 04/18/2018] [Indexed: 12/13/2022] Open
Abstract
Background Atypical iron overload without variation in the five clinically associated hereditary hemochromatosis genes is now recognized; however, their etiology remains unknown. Since the identification of iron overload in the bone morphogenetic protein 6 (Bmp6) knockout mouse, the search has been on for clinically pathogenic variants in the BMP6 gene. A recent report proposes that variants in the pro-peptide region of BMP6 are the underlying cause of several cases of iron overload. We performed targeted next-generation sequencing on three cases of atypical iron overload with Asian ethnicity and identified a p.Q118dup (aka p.E112indelEQ, p.Q115dup, p.Q118_L119insQ) variant in BMP6. The purpose of this study was to characterize the molecular function of the identified BMP6 variant. Molecular characterization by immunofluorescence microscopy and Western blotting of transfected cells, bioinformatics, and population analyses was performed. Results In contrast to reports for other BMP6 pro-peptide variants in this region, our data indicates that this variant does not affect the function of the mature BMP6 protein. Conclusions Our data suggest that assignment of disease causation in clinical cases of iron overload to pro-peptide variants in BMP6 should thus be treated with caution and requires biological characterization.
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Affiliation(s)
| | - Gautam Rishi
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland, 4059, Australia
| | - Eriza S Secondes
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland, 4059, Australia
| | - Lesa Ostini
- QIMR Berghofer Medical Research Institute, Brisbane, Australia
| | - Daniel F Wallace
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland, 4059, Australia
| | - Darrell H G Crawford
- Faculty of Medicine and Biomedical Sciences, The University of Queensland, Brisbane, Australia
| | | | - Paul Clark
- Princess Alexandra and Mater Hospitals, Brisbane, Australia
| | - V Nathan Subramaniam
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences, Queensland University of Technology (QUT), 60 Musk Avenue, Kelvin Grove, Brisbane, Queensland, 4059, Australia.
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27
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Abstract
Haemochromatosis is defined as systemic iron overload of genetic origin, caused by a reduction in the concentration of the iron regulatory hormone hepcidin, or a reduction in hepcidin-ferroportin binding. Hepcidin regulates the activity of ferroportin, which is the only identified cellular iron exporter. The most common form of haemochromatosis is due to homozygous mutations (specifically, the C282Y mutation) in HFE, which encodes hereditary haemochromatosis protein. Non-HFE forms of haemochromatosis due to mutations in HAMP, HJV or TFR2 are much rarer. Mutations in SLC40A1 (also known as FPN1; encoding ferroportin) that prevent hepcidin-ferroportin binding also cause haemochromatosis. Cellular iron excess in HFE and non-HFE forms of haemochromatosis is caused by increased concentrations of plasma iron, which can lead to the accumulation of iron in parenchymal cells, particularly hepatocytes, pancreatic cells and cardiomyocytes. Diagnosis is noninvasive and includes clinical examination, assessment of plasma iron parameters, imaging and genetic testing. The mainstay therapy is phlebotomy, although iron chelation can be used in some patients. Hepcidin supplementation might be an innovative future approach.
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Affiliation(s)
- Pierre Brissot
- INSERM, Univ. Rennes, INRA, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000 Rennes, France
| | - Antonello Pietrangelo
- Division of Internal Medicine 2 and Center for Haemochromatosis, University Hospital of Modena, Modena, Italy
| | - Paul C. Adams
- Department of Medicine, University of Western Ontario, London, Ontario, Canada
| | - Barbara de Graaff
- Menzies Institute for Medical Research, University of Tasmania, Tasmania, Australia
| | | | - Olivier Loréal
- INSERM, Univ. Rennes, INRA, Institut NUMECAN (Nutrition Metabolisms and Cancer) UMR_A 1341, UMR_S 1241, F-35000 Rennes, France
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28
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Vela D. Low hepcidin in liver fibrosis and cirrhosis; a tale of progressive disorder and a case for a new biochemical marker. Mol Med 2018; 24:5. [PMID: 30134796 PMCID: PMC6016890 DOI: 10.1186/s10020-018-0008-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 02/13/2018] [Indexed: 02/06/2023] Open
Abstract
Liver fibrosis is a precursor of liver cirrhosis, which is associated with increased mortality. Though liver biopsy remains the gold standard for the diagnosis of fibrosis, noninvasive biochemical methods are cost-effective, practical and are not linked with major risks of complications. In this respect, serum hepcidin, has emerged as a new marker of fibrosis and cirrhosis. In this review the discussion uncovers molecular links between hepcidin disturbance and liver fibrosis/cirrhosis. The discussion also expands on clinical studies that suggest that hepcidin can potentially be used as a biochemical parameter of fibrosis/cirrhosis and target of therapeutic strategies to treat liver diseases. The debatable issues such as the complicated nature of hepcidin disturbance in non-alcoholic liver disease, serum levels of hepcidin in acute hepatitis C virus infection, cause of hepcidin disturbance in autoimmune hepatitis and hepatic insulin resistance are discussed, with potential solutions unveiled in order to be studied by future research.
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Affiliation(s)
- Driton Vela
- Department of Physiology, Faculty of Medicine, University of Prishtina, Martyr's Boulevard n.n, Prishtina, 10000, Kosovo.
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29
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Girelli D, Ugolini S, Busti F, Marchi G, Castagna A. Modern iron replacement therapy: clinical and pathophysiological insights. Int J Hematol 2017; 107:16-30. [PMID: 29196967 DOI: 10.1007/s12185-017-2373-3] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2017] [Accepted: 11/24/2017] [Indexed: 12/13/2022]
Abstract
Iron deficiency, with or without anemia, is extremely frequent worldwide, representing a major public health problem. Iron replacement therapy dates back to the seventeenth century, and has progressed relatively slowly until recently. Both oral and intravenous traditional iron formulations are known to be far from ideal, mainly because of tolerability and safety issues, respectively. At the beginning of this century, the discovery of hepcidin/ferroportin axis has represented a turning point in the knowledge of the pathophysiology of iron metabolism disorders, ushering a new era. In the meantime, advances in the pharmaceutical technologies are producing newer iron formulations aimed at minimizing the problems inherent with traditional approaches. The pharmacokinetic of oral and parenteral iron is substantially different, and diversities have become even clearer in light of the hepcidin master role in regulating systemic iron homeostasis. Here we review how iron therapy is changing because of such important advances in both pathophysiology and pharmacology.
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Affiliation(s)
- Domenico Girelli
- Department of Medicine, Section of Internal Medicine, Veneto Region Referral Center for Iron Metabolism Disorders, Center of Excellence for Rare Hematological Diseases "EuroBloodNet", University of Verona, Policlinico G.B. Rossi, 37134, Verona, Italy.
| | - Sara Ugolini
- Department of Medicine, Section of Internal Medicine, Veneto Region Referral Center for Iron Metabolism Disorders, Center of Excellence for Rare Hematological Diseases "EuroBloodNet", University of Verona, Policlinico G.B. Rossi, 37134, Verona, Italy
| | - Fabiana Busti
- Department of Medicine, Section of Internal Medicine, Veneto Region Referral Center for Iron Metabolism Disorders, Center of Excellence for Rare Hematological Diseases "EuroBloodNet", University of Verona, Policlinico G.B. Rossi, 37134, Verona, Italy
| | - Giacomo Marchi
- Department of Medicine, Section of Internal Medicine, Veneto Region Referral Center for Iron Metabolism Disorders, Center of Excellence for Rare Hematological Diseases "EuroBloodNet", University of Verona, Policlinico G.B. Rossi, 37134, Verona, Italy
| | - Annalisa Castagna
- Department of Medicine, Section of Internal Medicine, Veneto Region Referral Center for Iron Metabolism Disorders, Center of Excellence for Rare Hematological Diseases "EuroBloodNet", University of Verona, Policlinico G.B. Rossi, 37134, Verona, Italy
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Kawabata H. The mechanisms of systemic iron homeostasis and etiology, diagnosis, and treatment of hereditary hemochromatosis. Int J Hematol 2017; 107:31-43. [PMID: 29134618 DOI: 10.1007/s12185-017-2365-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2017] [Accepted: 11/08/2017] [Indexed: 02/06/2023]
Abstract
Hereditary hemochromatosis (HH) is a group of genetic iron overload disorders that manifest with various symptoms, including hepatic dysfunction, diabetes, and cardiomyopathy. Classic HH type 1, which is common in Caucasians, is caused by bi-allelic mutations of HFE. Severe types of HH are caused by either bi-allelic mutations of HFE2 that encodes hemojuvelin (type 2A) or HAMP that encodes hepcidin (type 2B). HH type 3, which is of intermediate severity, is caused by bi-allelic mutations of TFR2 that encodes transferrin receptor 2. Mutations of SLC40A1 that encodes ferroportin, the only cellular iron exporter, causes either HH type 4A (loss-of-function mutations) or HH type 4B (gain-of-function mutations). Studies on these gene products uncovered a part of the mechanisms of the systemic iron regulation; HFE, hemojuvelin, and TFR2 are involved in iron sensing and stimulating hepcidin expression, and hepcidin downregulates the expression of ferroportin of the target cells. Phlebotomy is the standard treatment for HH, and early initiation of the treatment is essential for preventing irreversible organ damage. However, because of the rarity and difficulty in making the genetic diagnosis, a large proportion of patients with non-HFE HH might have been undiagnosed; therefore, awareness of this disorder is important.
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Affiliation(s)
- Hiroshi Kawabata
- Department of Hematology and Immunology, Kanazawa Medical University, 1-1 Daigaku, Uchinada-machi, Ishikawa-ken, 920-0293, Japan.
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31
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Canali S, Wang CY, Zumbrennen-Bullough KB, Bayer A, Babitt JL. Bone morphogenetic protein 2 controls iron homeostasis in mice independent of Bmp6. Am J Hematol 2017; 92:1204-1213. [PMID: 28815688 DOI: 10.1002/ajh.24888] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Revised: 08/08/2017] [Accepted: 08/14/2017] [Indexed: 12/24/2022]
Abstract
Hepcidin is a key iron regulatory hormone that controls expression of the iron exporter ferroportin to increase the iron supply when needed to support erythropoiesis and other essential functions, but to prevent the toxicity of iron excess. The bone morphogenetic protein (BMP)-SMAD signaling pathway, through the ligand BMP6 and the co-receptor hemojuvelin, is a central regulator of hepcidin transcription in the liver in response to iron. Here, we show that dietary iron loading has a residual ability to induce Smad signaling and hepcidin expression in Bmp6-/- mice, effects that are blocked by a neutralizing BMP2/4 antibody. Moreover, BMP2/4 antibody inhibits hepcidin expression and induces iron loading in wildtype mice, whereas a BMP4 antibody has no effect. Bmp2 mRNA is predominantly expressed in endothelial cells of the liver, where its baseline expression is higher, but its induction by iron is less robust than Bmp6. Mice with a conditional ablation of Bmp2 in endothelial cells exhibit hepcidin deficiency, serum iron overload, and tissue iron loading in liver, pancreas and heart, with reduced spleen iron. Together, these data demonstrate that in addition to BMP6, endothelial cell BMP2 has a non-redundant role in hepcidin regulation by iron.
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Affiliation(s)
- Susanna Canali
- Program in Anemia Signaling Research, Division of Nephrology, Program in Membrane Biology, Center for Systems Biology; Massachusetts General Hospital, Harvard Medical School; Boston Massachusetts
| | - Chia-Yu Wang
- Program in Anemia Signaling Research, Division of Nephrology, Program in Membrane Biology, Center for Systems Biology; Massachusetts General Hospital, Harvard Medical School; Boston Massachusetts
| | - Kimberly B. Zumbrennen-Bullough
- Program in Anemia Signaling Research, Division of Nephrology, Program in Membrane Biology, Center for Systems Biology; Massachusetts General Hospital, Harvard Medical School; Boston Massachusetts
| | - Abraham Bayer
- Program in Anemia Signaling Research, Division of Nephrology, Program in Membrane Biology, Center for Systems Biology; Massachusetts General Hospital, Harvard Medical School; Boston Massachusetts
| | - Jodie L. Babitt
- Program in Anemia Signaling Research, Division of Nephrology, Program in Membrane Biology, Center for Systems Biology; Massachusetts General Hospital, Harvard Medical School; Boston Massachusetts
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Deletion of BMP6 worsens the phenotype of HJV-deficient mice and attenuates hepcidin levels reached after LPS challenge. Blood 2017; 130:2339-2343. [PMID: 29021231 DOI: 10.1182/blood-2017-07-795658] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/21/2017] [Indexed: 12/20/2022] Open
Abstract
Lack of either bone morphogenetic protein 6 (BMP6) or the BMP coreceptor hemojuvelin (HJV) in mice leads to a similar phenotype with hepcidin insufficiency, hepatic iron loading, and extrahepatic iron accumulation in males. This is consistent with the current views that HJV is a coreceptor for BMP6 in hepatocytes. To determine whether BMP6 and HJV may also signal to hepcidin independently of each other, we intercrossed Hjv-/- and Bmp6-/- mice and compared the phenotype of animals of the F2 progeny. Loss of Bmp6 further repressed Smad signaling and hepcidin expression in the liver of Hjv-/- mice of both sexes, and led to iron accumulation in the pancreas and the heart of females. These data suggest that, in Hjv-/- females, Bmp6 can provide a signal adequate to maintain hepcidin to a level sufficient to avoid extrahepatic iron loading. We also examined the impact of Bmp6 and/or Hjv deletion on the regulation of hepcidin by inflammation. Our data show that lack of 1 or both molecules does not prevent induction of hepcidin by lipopolysaccharide (LPS). However, BMP/Smad signaling in unchallenged animals is determinant for the level of hepcidin reached after stimulation, which is consistent with a synergy between interleukin 6/STAT3 and BMP/SMAD signaling in regulating hepcidin during inflammation.
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The interaction of iron and the genome: For better and for worse. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2017; 774:25-32. [DOI: 10.1016/j.mrrev.2017.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 07/28/2017] [Accepted: 09/12/2017] [Indexed: 12/11/2022]
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Abstract
Iron homeostasis relies on the amount of its absorption by the intestine and its release from storage sites, the macrophages. Iron homeostasis is also dependent on the amount of iron used for the erythropoiesis. Hepcidin, which is synthesized predominantly by the liver, is the main regulator of iron metabolism. Hepcidin reduces serum iron by inhibiting the iron exporter, ferroportin expressed both tissues, the intestine and the macrophages. In addition, in the enterocytes, hepcidin inhibits the iron influx by acting on the apical transporter, DMT1. A defect of hepcidin expression leading to the appearance of a parenchymal iron overload may be genetic or secondary to dyserythropoiesis. The exploration of genetic hemochromatosis has revealed the involvement of several genes, including the recently described BMP6. Non-transfusional secondary hemochromatosis is due to hepcidin repression by cytokines, in particular the erythroferone factor that is produced directly by the erythroid precursors. Iron overload is correlated with the appearance of a free form of iron called NTBI. The influx of NTBI seems to be mediated by ZIP14 transporter in the liver and by calcium channels in the cardiomyocytes. Beside the liver, hepcidin is expressed at lesser extent in several extrahepatic tissues where it plays its ancestral role of antimicrobial peptide. In the kidney, hepcidin modulates defense barriers against urinary tract infections. In the heart, hepcidin maintains tissue iron homeostasis by an autocrine regulation of ferroprotine expression on the surface of cardiomyocytes. In conclusion, hepcidin remains a promising therapeutic tool in various iron pathologies.
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