1
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Debbiche R, Elbahnsi A, Uguen K, Ka C, Callebaut I, Le Gac G. Insights into the role of glycerophospholipids on the iron export function of SLC40A1 and the molecular mechanisms of ferroportin disease. FASEB J 2024; 38:e23725. [PMID: 38959016 DOI: 10.1096/fj.202400337r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 05/13/2024] [Accepted: 05/23/2024] [Indexed: 07/04/2024]
Abstract
SLC40A1 is the sole iron export protein reported in mammals. In humans, its dysfunction is responsible for ferroportin disease, an inborn error of iron metabolism transmitted as an autosomal dominant trait and observed in different ethnic groups. As a member of the major facilitator superfamily, SLC40A1 requires a series of conformational changes to enable iron translocation across the plasma membrane. The influence of lipids on protein stability and its conformational changes has been little investigated to date. Here, we combine molecular dynamics simulations of SLC40A1 embedded in membrane bilayers with experimental alanine scanning mutagenesis to analyze the specific role of glycerophospholipids. We identify four basic residues (Lys90, Arg365, Lys366, and Arg371) that are located at the membrane-cytosol interface and consistently interact with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine (POPE) molecules. These residues surround a network of salt bridges and hydrogens bonds that play a critical role in stabilizing SLC40A1 in its basal outward-facing conformation. More deeply embedded in the plasma membrane, we identify Arg179 as a charged amino acid residue also tightly interacting with lipid polar heads. This results in a local deformation of the lipid bilayer. Interestingly, Arg179 is adjacent to Arg178, which forms a functionally important salt-bridge with Asp473 and is a recurrently associated with ferroportin disease when mutated to glutamine. We demonstrate that the two p.Arg178Gln and p.Arg179Thr missense variants have similar functional behaviors. These observations provide insights into the role of phospholipids in the formation/disruption of the SLC40A1 inner gate, and give a better understanding of the diversity of molecular mechanisms of ferroportin disease.
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Affiliation(s)
- Rim Debbiche
- University of Brest, Inserm, EFS, UMR 1078, GGB, Brest, France
| | - Ahmad Elbahnsi
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Paris, France
| | - Kévin Uguen
- University of Brest, Inserm, EFS, UMR 1078, GGB, Brest, France
- CHU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Brest, France
| | - Chandran Ka
- University of Brest, Inserm, EFS, UMR 1078, GGB, Brest, France
- CHU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Brest, France
| | - Isabelle Callebaut
- Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, IMPMC, Sorbonne Université, Muséum National d'Histoire Naturelle, UMR CNRS 7590, IRD, Paris, France
| | - Gérald Le Gac
- University of Brest, Inserm, EFS, UMR 1078, GGB, Brest, France
- CHU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Brest, France
- Laboratory of Excellence GR-Ex, Paris, France
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2
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Leman R, Parfait B, Vidaud D, Girodon E, Pacot L, Le Gac G, Ka C, Ferec C, Fichou Y, Quesnelle C, Aucouturier C, Muller E, Vaur D, Castera L, Boulouard F, Ricou A, Tubeuf H, Soukarieh O, Gaildrat P, Riant F, Guillaud‐Bataille M, Caputo SM, Caux‐Moncoutier V, Boutry‐Kryza N, Bonnet‐Dorion F, Schultz I, Rossing M, Quenez O, Goldenberg L, Harter V, Parsons MT, Spurdle AB, Frébourg T, Martins A, Houdayer C, Krieger S. SPiP: Splicing Prediction Pipeline, a machine learning tool for massive detection of exonic and intronic variant effects on mRNA splicing. Hum Mutat 2022; 43:2308-2323. [PMID: 36273432 PMCID: PMC10946553 DOI: 10.1002/humu.24491] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 10/06/2022] [Accepted: 10/18/2022] [Indexed: 01/25/2023]
Abstract
Modeling splicing is essential for tackling the challenge of variant interpretation as each nucleotide variation can be pathogenic by affecting pre-mRNA splicing via disruption/creation of splicing motifs such as 5'/3' splice sites, branch sites, or splicing regulatory elements. Unfortunately, most in silico tools focus on a specific type of splicing motif, which is why we developed the Splicing Prediction Pipeline (SPiP) to perform, in one single bioinformatic analysis based on a machine learning approach, a comprehensive assessment of the variant effect on different splicing motifs. We gathered a curated set of 4616 variants scattered all along the sequence of 227 genes, with their corresponding splicing studies. The Bayesian analysis provided us with the number of control variants, that is, variants without impact on splicing, to mimic the deluge of variants from high-throughput sequencing data. Results show that SPiP can deal with the diversity of splicing alterations, with 83.13% sensitivity and 99% specificity to detect spliceogenic variants. Overall performance as measured by area under the receiving operator curve was 0.986, better than SpliceAI and SQUIRLS (0.965 and 0.766) for the same data set. SPiP lends itself to a unique suite for comprehensive prediction of spliceogenicity in the genomic medicine era. SPiP is available at: https://sourceforge.net/projects/splicing-prediction-pipeline/.
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Affiliation(s)
- Raphaël Leman
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
- UNICAENNormandie UniversitéCaenFrance
| | - Béatrice Parfait
- Service de Génétique et Biologie Moléculaires, APHP, HUPCHôpital CochinParisFrance
| | - Dominique Vidaud
- Service de Génétique et Biologie Moléculaires, APHP, HUPCHôpital CochinParisFrance
| | - Emmanuelle Girodon
- Service de Génétique et Biologie Moléculaires, APHP, HUPCHôpital CochinParisFrance
| | - Laurence Pacot
- Service de Génétique et Biologie Moléculaires, APHP, HUPCHôpital CochinParisFrance
| | - Gérald Le Gac
- Inserm UMR1078, Genetics, Functional Genomics and BiotechnologyUniversité de Bretagne OccidentaleBrestFrance
| | - Chandran Ka
- Inserm UMR1078, Genetics, Functional Genomics and BiotechnologyUniversité de Bretagne OccidentaleBrestFrance
| | - Claude Ferec
- Inserm UMR1078, Genetics, Functional Genomics and BiotechnologyUniversité de Bretagne OccidentaleBrestFrance
| | - Yann Fichou
- Inserm UMR1078, Genetics, Functional Genomics and BiotechnologyUniversité de Bretagne OccidentaleBrestFrance
| | - Céline Quesnelle
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
| | - Camille Aucouturier
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | - Etienne Muller
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
| | - Dominique Vaur
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | - Laurent Castera
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | - Flavie Boulouard
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | - Agathe Ricou
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | - Hélène Tubeuf
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
- Integrative BiosoftwareRouenFrance
| | - Omar Soukarieh
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | | | - Florence Riant
- Laboratoire de Génétique, AP‐HPGH Saint‐Louis‐Lariboisière‐Fernand WidalParisFrance
| | | | - Sandrine M. Caputo
- Department of Genetics, Institut CurieParis Sciences Lettres Research UniversityParisFrance
| | | | - Nadia Boutry‐Kryza
- Unité Mixte de Génétique Constitutionnelle des Cancers FréquentsHospices Civils de LyonLyonFrance
| | - Françoise Bonnet‐Dorion
- Departement de Biopathologie Unité de Génétique ConstitutionnelleInstitut Bergonie—INSERM U1218BordeauxFrance
| | - Ines Schultz
- Laboratoire d'OncogénétiqueCentre Paul StraussStrasbourgFrance
| | - Maria Rossing
- Centre for Genomic Medicine, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
| | - Olivier Quenez
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | - Louis Goldenberg
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | - Valentin Harter
- Department of BiostatisticsBaclesse Unicancer CenterCaenFrance
| | - Michael T. Parsons
- Department of Genetics and Computational BiologyQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Amanda B. Spurdle
- Department of Genetics and Computational BiologyQIMR Berghofer Medical Research InstituteHerstonQueenslandAustralia
| | - Thierry Frébourg
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
- Department of geneticsRouen University HospitalRouenFrance
| | - Alexandra Martins
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
| | - Claude Houdayer
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
- Department of geneticsRouen University HospitalRouenFrance
| | - Sophie Krieger
- Laboratoire de Biologie et Génétique du CancerCentre François BaclesseCaenFrance
- Inserm U1245, UNIROUEN, FHU‐G4 génomiqueNormandie UniversitéRouenFrance
- UNICAENNormandie UniversitéCaenFrance
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3
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Shahandeh A, Bui BV, Finkelstein DI, Nguyen CTO. Effects of Excess Iron on the Retina: Insights From Clinical Cases and Animal Models of Iron Disorders. Front Neurosci 2022; 15:794809. [PMID: 35185447 PMCID: PMC8851357 DOI: 10.3389/fnins.2021.794809] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 12/17/2021] [Indexed: 01/19/2023] Open
Abstract
Iron plays an important role in a wide range of metabolic pathways that are important for neuronal health. Excessive levels of iron, however, can promote toxicity and cell death. An example of an iron overload disorder is hemochromatosis (HH) which is a genetic disorder of iron metabolism in which the body’s ability to regulate iron absorption is altered, resulting in iron build-up and injury in several organs. The retina was traditionally assumed to be protected from high levels of systemic iron overload by the blood-retina barrier. However, recent data shows that expression of genes that are associated with HH can disrupt retinal iron metabolism. Thus, the effects of iron overload on the retina have become an area of research interest, as excessively high levels of iron are implicated in several retinal disorders, most notably age–related macular degeneration. This review is an effort to highlight risk factors for excessive levels of systemic iron build-up in the retina and its potential impact on the eye health. Information is integrated across clinical and preclinical animal studies to provide insights into the effects of systemic iron loading on the retina.
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Affiliation(s)
- Ali Shahandeh
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - Bang V. Bui
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
| | - David I. Finkelstein
- Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, VIC, Australia
| | - Christine T. O. Nguyen
- Department of Optometry and Vision Sciences, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Parkville, VIC, Australia
- *Correspondence: Christine T. O. Nguyen,
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4
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Restivo C, Le Bras M, Deguigne P, Le Glatin L, Guerry C, Férec C, Le Maréchal C, Beloeil R, Fichou Y. The novel c.634+
4A
>G splicing variant in
RHCE
results in weak C and e antigen expression in a pregnant woman originated from Japan. Transfusion 2022; 62:758-763. [DOI: 10.1111/trf.16811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 01/03/2022] [Accepted: 01/12/2022] [Indexed: 11/28/2022]
Affiliation(s)
- Cynthia Restivo
- Univ Brest, Inserm, EFS, UMR1078, GGB Brest France
- Laboratory of Excellence GR‐Ex Paris France
| | - Myriam Le Bras
- Laboratoire d'Immuno‐Hématologie Etablissement français du sang (EFS) Centre – Pays de la Loire Angers France
| | - Pierre‐Antoine Deguigne
- Laboratoire d'Immuno‐Hématologie Etablissement français du sang (EFS) Centre – Pays de la Loire Angers France
| | - Laurence Le Glatin
- Laboratoire de Biologie Moléculaire des Groupes Sanguins (LBMGS), EFS Bretagne Brest France
| | - Christine Guerry
- Laboratoire de Biologie Moléculaire des Groupes Sanguins (LBMGS), EFS Bretagne Brest France
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR1078, GGB Brest France
- Service de Génétique Médicale, CHRU Brest Brest France
| | - Cédric Le Maréchal
- Univ Brest, Inserm, EFS, UMR1078, GGB Brest France
- Laboratoire de Biologie Moléculaire des Groupes Sanguins (LBMGS), EFS Bretagne Brest France
- Service de Génétique Médicale, CHRU Brest Brest France
| | - Rémi Beloeil
- Laboratoire de Biologie Moléculaire des Groupes Sanguins (LBMGS), EFS Bretagne Brest France
| | - Yann Fichou
- Univ Brest, Inserm, EFS, UMR1078, GGB Brest France
- Laboratory of Excellence GR‐Ex Paris France
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5
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Insights into the Role of the Discontinuous TM7 Helix of Human Ferroportin through the Prism of the Asp325 Residue. Int J Mol Sci 2021; 22:ijms22126412. [PMID: 34203920 PMCID: PMC8232785 DOI: 10.3390/ijms22126412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 06/09/2021] [Accepted: 06/11/2021] [Indexed: 11/16/2022] Open
Abstract
The negatively charged Asp325 residue has proved to be essential for iron export by human (HsFPN1) and primate Philippine tarsier (TsFpn) ferroportin, but its exact role during the iron transport cycle is still to be elucidated. It has been posited as being functionally equivalent to the metal ion-coordinating residue His261 in the C-lobe of the bacterial homolog BbFpn, but the two residues arise in different sequence motifs of the discontinuous TM7 transmembrane helix. Furthermore, BbFpn is not subject to extracellular regulation, contrary to its mammalian orthologues which are downregulated by hepcidin. To get further insight into the molecular mechanisms related to iron export in mammals in which Asp325 is involved, we investigated the behavior of the Asp325Ala, Asp325His, and Asp325Asn mutants in transiently transfected HEK293T cells, and performed a comparative structural analysis. Our biochemical studies clearly distinguished between the Asp325Ala and Asp325His mutants, which result in a dramatic decrease in plasma membrane expression of FPN1, and the Asp325Asn mutant, which alters iron egress without affecting protein localization. Analysis of the 3D structures of HsFPN1 and TsFpn in the outward-facing (OF) state indicated that Asp325 does not interact directly with metal ions but is involved in the modulation of Cys326 metal-binding capacity. Moreover, models of the architecture of mammalian proteins in the inward-facing (IF) state suggested that Asp325 may form an inter-lobe salt-bridge with Arg40 (TM1) when not interacting with Cys326. These findings allow to suggest that Asp325 may be important for fine-tuning iron recognition in the C-lobe, as well as for local structural changes during the IF-to-OF transition at the extracellular gate level. Inability to form a salt-bridge between TM1 and TM7b during iron translocation could lead to protein instability, as shown by the Asp325Ala and Asp325His mutants.
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6
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Human ferroportin mediates proton-coupled active transport of iron. Blood Adv 2021; 4:4758-4768. [PMID: 33007076 DOI: 10.1182/bloodadvances.2020001864] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 08/27/2020] [Indexed: 12/14/2022] Open
Abstract
As the sole iron exporter in humans, ferroportin controls systemic iron homeostasis through exporting iron into the blood plasma. The molecular mechanism of how ferroportin exports iron under various physiological settings remains unclear. Here we found that purified ferroportin incorporated into liposomes preferentially transports Fe2+ and exhibits lower affinities of transporting other divalent metal ions. The iron transport by ferroportin is facilitated by downhill proton gradients at the same direction. Human ferroportin is also capable of transporting protons, and this activity is tightly coupled to the iron transport. Remarkably, ferroportin can conduct active transport uphill against the iron gradient, with favorable charge potential providing the driving force. Targeted mutagenesis suggests that the iron translocation site is located at the pore region of human ferroportin. Together, our studies enhance the mechanistic understanding by which human ferroportin transports iron and suggest that a combination of electrochemical gradients regulates iron export.
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7
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Kang W, Barad A, Clark AG, Wang Y, Lin X, Gu Z, O'Brien KO. Ethnic Differences in Iron Status. Adv Nutr 2021; 12:1838-1853. [PMID: 34009254 PMCID: PMC8483971 DOI: 10.1093/advances/nmab035] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/02/2021] [Accepted: 03/05/2021] [Indexed: 02/07/2023] Open
Abstract
Iron is unique among all minerals in that humans have no regulatable excretory pathway to eliminate excess iron after it is absorbed. Iron deficiency anemia occurs when absorbed iron is not sufficient to meet body iron demands, whereas iron overload and subsequent deposition of iron in key organs occur when absorbed iron exceeds body iron demands. Over time, iron accumulation in the body can increase risk of chronic diseases, including cirrhosis, diabetes, and heart failure. To date, only ∼30% of the interindividual variability in iron absorption can be captured by iron status biomarkers or iron regulatory hormones. Much of the regulation of iron absorption may be under genetic control, but these pathways have yet to be fully elucidated. Genome-wide and candidate gene association studies have identified several genetic variants that are associated with variations in iron status, but the majority of these data were generated in European populations. The purpose of this review is to summarize genetic variants that have been associated with alterations in iron status and to highlight the influence of ethnicity on the risk of iron deficiency or overload. Using extant data in the literature, linear mixed-effects models were constructed to explore ethnic differences in iron status biomarkers. This approach found that East Asians had significantly higher concentrations of iron status indicators (serum ferritin, transferrin saturation, and hemoglobin) than Europeans, African Americans, or South Asians. African Americans exhibited significantly lower hemoglobin concentrations compared with other ethnic groups. Further studies of the genetic basis for ethnic differences in iron metabolism and on how it affects disease susceptibility among different ethnic groups are needed to inform population-specific recommendations and personalized nutrition interventions for iron-related disorders.
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Affiliation(s)
- Wanhui Kang
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Alexa Barad
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Andrew G Clark
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA,Department of Computational Biology, Cornell University, Ithaca, NY, USA
| | - Yiqin Wang
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
| | - Xu Lin
- Shanghai Institute of Nutrition and Health, Chinese Academy of Sciences, Shanghai, China
| | - Zhenglong Gu
- Division of Nutritional Sciences, Cornell University, Ithaca, NY, USA
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8
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Ferdinandusse S, McWalter K, Te Brinke H, IJlst L, Mooijer PM, Ruiter JPN, van Lint AEM, Pras-Raves M, Wever E, Millan F, Guillen Sacoto MJ, Begtrup A, Tarnopolsky M, Brady L, Ladda RL, Sell SL, Nowak CB, Douglas J, Tian C, Ulm E, Perlman S, Drack AV, Chong K, Martin N, Brault J, Brokamp E, Toro C, Gahl WA, Macnamara EF, Wolfe L, Waisfisz Q, Zwijnenburg PJG, Ziegler A, Barth M, Smith R, Ellingwood S, Gaebler-Spira D, Bakhtiari S, Kruer MC, van Kampen AHC, Wanders RJA, Waterham HR, Cassiman D, Vaz FM. An autosomal dominant neurological disorder caused by de novo variants in FAR1 resulting in uncontrolled synthesis of ether lipids. Genet Med 2021; 23:740-750. [PMID: 33239752 PMCID: PMC8026396 DOI: 10.1038/s41436-020-01027-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 10/15/2020] [Accepted: 10/21/2020] [Indexed: 12/25/2022] Open
Abstract
PURPOSE In this study we investigate the disease etiology in 12 patients with de novo variants in FAR1 all resulting in an amino acid change at position 480 (p.Arg480Cys/His/Leu). METHODS Following next-generation sequencing and clinical phenotyping, functional characterization was performed in patients' fibroblasts using FAR1 enzyme analysis, FAR1 immunoblotting/immunofluorescence, and lipidomics. RESULTS All patients had spastic paraparesis and bilateral congenital/juvenile cataracts, in most combined with speech and gross motor developmental delay and truncal hypotonia. FAR1 deficiency caused by biallelic variants results in defective ether lipid synthesis and plasmalogen deficiency. In contrast, patients' fibroblasts with the de novo FAR1 variants showed elevated plasmalogen levels. Further functional studies in fibroblasts showed that these variants cause a disruption of the plasmalogen-dependent feedback regulation of FAR1 protein levels leading to uncontrolled ether lipid production. CONCLUSION Heterozygous de novo variants affecting the Arg480 residue of FAR1 lead to an autosomal dominant disorder with a different disease mechanism than that of recessive FAR1 deficiency and a diametrically opposed biochemical phenotype. Our findings show that for patients with spastic paraparesis and bilateral cataracts, FAR1 should be considered as a candidate gene and added to gene panels for hereditary spastic paraplegia, cerebral palsy, and juvenile cataracts.
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Affiliation(s)
- Sacha Ferdinandusse
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands.
| | | | - Heleen Te Brinke
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Lodewijk IJlst
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Petra M Mooijer
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Jos P N Ruiter
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Alida E M van Lint
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Mia Pras-Raves
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
- Core Facility Metabolomics, Amsterdam UMC, Amsterdam, The Netherlands
- Bioinformatics Laboratory, Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | - Eric Wever
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
- Core Facility Metabolomics, Amsterdam UMC, Amsterdam, The Netherlands
- Bioinformatics Laboratory, Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
| | | | | | | | - Mark Tarnopolsky
- Department of Pediatrics, McMaster University Children's Hospital, Hamilton, ON, Canada
| | - Lauren Brady
- Department of Pediatrics, McMaster University Children's Hospital, Hamilton, ON, Canada
| | - Roger L Ladda
- Department of Pediatrics, Penn State Children's Hospital, Hershey, PA, USA
| | - Susan L Sell
- Department of Pediatrics, Penn State Children's Hospital, Hershey, PA, USA
| | - Catherine B Nowak
- The Feingold Center for Children, Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - Jessica Douglas
- The Feingold Center for Children, Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA
| | - Cuixia Tian
- Division of Neurology, Cincinnati Children's Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Elizabeth Ulm
- Division of Human Genetics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Seth Perlman
- Department of Neurology, University of Iowa Hospitals and Clinics, Iowa City, IA, USA
| | - Arlene V Drack
- Department of Ophthalmology and Visual Sciences, University of Iowa, Iowa City, IA, USA
| | - Karen Chong
- Mount Sinai Hospital, Department of Obstetrics and Gynecology, Prenatal Diagnosis and Medical Genetics Program, Toronto, ON, Canada
| | - Nicole Martin
- Mount Sinai Hospital, Department of Obstetrics and Gynecology, Prenatal Diagnosis and Medical Genetics Program, Toronto, ON, Canada
| | - Jennifer Brault
- Vanderbilt University Medical Center, Department of Pediatrics, Nashville, TN, USA
| | - Elly Brokamp
- Vanderbilt University Medical Center, Department of Pediatrics, Nashville, TN, USA
| | - Camilo Toro
- NIH Undiagnosed Diseases Program, Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - William A Gahl
- NIH Undiagnosed Diseases Program, Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Ellen F Macnamara
- NIH Undiagnosed Diseases Program, Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Lynne Wolfe
- NIH Undiagnosed Diseases Program, Office of the Clinical Director, National Human Genome Research Institute, NIH, Bethesda, MD, USA
| | - Quinten Waisfisz
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Petra J G Zwijnenburg
- Department of Clinical Genetics, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Alban Ziegler
- Genetic department, University Hospital Angers, Angers, France
| | - Magalie Barth
- Genetic department, University Hospital Angers, Angers, France
| | - Rosemarie Smith
- Division of Genetics, Department of Pediatrics, Maine Medical Center, Portland, ME, USA
| | - Sara Ellingwood
- Division of Genetics, Department of Pediatrics, Maine Medical Center, Portland, ME, USA
| | - Deborah Gaebler-Spira
- Feinberg Northwestern University School of Medicine, Shirley Ryan Ability Lab, Chicago, IL, USA
| | - Somayeh Bakhtiari
- Barrow Neurological Institute, Phoenix Children's Hospital and University of Arizona College of Medicine, Phoenix, AZ, USA
| | - Michael C Kruer
- Barrow Neurological Institute, Phoenix Children's Hospital and University of Arizona College of Medicine, Phoenix, AZ, USA
| | - Antoine H C van Kampen
- Bioinformatics Laboratory, Department of Epidemiology and Data Science, Amsterdam Public Health Research Institute, Amsterdam UMC, University of Amsterdam, Amsterdam, The Netherlands
- Biosystems Data Analysis, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Ronald J A Wanders
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - Hans R Waterham
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands
| | - David Cassiman
- Department of Gastroenterology-Hepatology, Metabolic Center, University Hospitals Leuven, Leuven, Belgium
| | - Frédéric M Vaz
- Laboratory Genetic Metabolic Diseases, Amsterdam UMC, University of Amsterdam, Department of Clinical Chemistry, Amsterdam Gastroenterology Endocrinology Metabolism, Amsterdam, The Netherlands.
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9
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Evidence for dimerization of ferroportin in a human hepatic cell line using proximity ligation assays. Biosci Rep 2021; 40:222672. [PMID: 32301493 PMCID: PMC7201565 DOI: 10.1042/bsr20191499] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 04/08/2020] [Accepted: 04/16/2020] [Indexed: 12/30/2022] Open
Abstract
Mutations in the only known iron exporter ferroportin (FPN) in humans are associated with the autosomal dominantly inherited iron overload disorder ferroportin disease or type IV hereditary hemochromatosis (HH). While our knowledge of the central role of FPN in iron homeostasis has grown in the last 20 years, there exist some questions surrounding the structure and membrane topology of FPN with conflicting data on whether this receptor acts as a monomer or a multimer. To investigate and determine if FPN dimerization occurs in cells, we used novel tools including a variety of different FPN constructs expressing different tagged versions of the protein, a novel antibody that only detects cell surface FPN and proximity ligation assays. The results of the present study suggest that both the carboxy- and amino-termini of the FPN protein are intracellular. We also show that exogenously transfected FPN forms dimers; these dimers can be formed between the wild-type and mutant FPN proteins. This is the first study to examine the intracellular dimerization of FPN protein. Using proximity ligation assays, we show intracellular localization of FPN dimers and the interaction between FPN and hepcidin proteins as well. These results have important implications in the field of iron metabolism and add to our knowledge about FPN membrane topology and physiology of iron transport. This will be of importance in understanding the clinical implications of FPN mutations and of interest to future research aimed at targeting FPN expression to modulate iron homeostasis.
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10
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Thongbut J, Laengsri V, Raud L, Promwong C, I-Na-Ayudhya C, Férec C, Nuchnoi P, Fichou Y. Nation-wide investigation of RHD variants in Thai blood donors: Impact for molecular diagnostics. Transfusion 2020; 61:931-938. [PMID: 33377204 DOI: 10.1111/trf.16242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/23/2020] [Accepted: 12/06/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND Knowledge of the molecular determinants driving antigen expression is critical to design, optimize, and implement a genotyping approach on a population-specific basis. Although RHD gene variability has been extensively reported in Caucasians, Africans, and East-Asians, it remains to be explored in Southeast Asia. Thus the molecular basis of non-D+ blood donors was investigated in Thailand. STUDY DESIGN AND METHODS First, 1176 blood samples exhibiting an inconclusive or negative result by automated serological testing were collected in the 12 Regional Blood Centres of the Thai Red Cross located throughout Thailand. Second, the RHD gene was analyzed in all samples by 1) quantitative multiplex PCR of short fluorescent fragments, and 2) direct sequencing, when necessary, for identifying structural variants and single nucleotide variants, respectively. RESULTS Additional serological typing yielded 51 and 1125 samples with weak/partial D and D-negative (D-) phenotype, respectively. In the first subset, partial RHD*06.03 was the most common variant allele (allele frequency: 18.6%). In the second subset, the whole deletion of the gene is largely the most frequent (allele frequency: 84.9%), followed by the Asian DEL allele found in 15.6% of the samples. Eight novel alleles with various mutational mechanisms were identified. CONCLUSION We report, for the first time at the national level, the molecular basis of weak/partial D and serologically D- phenotypes in Thai blood donors. The design and implementation of a dedicated diagnostic strategy in blood donors and patients are the very next steps for optimizing the management and supply of RBC units in Thailand.
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Affiliation(s)
- Jairak Thongbut
- Center of Research and Innovation, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand.,National Blood Centre, Thai Red Cross Society, Bangkok, Thailand
| | - Vishuda Laengsri
- Center of Research and Innovation, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | | | - Charuporn Promwong
- National Blood Centre, Thai Red Cross Society, Bangkok, Thailand.,Sunpasitthiprasong Hospital, Ubon Ratchathani, Thailand
| | - Chartchalerm I-Na-Ayudhya
- Department of Clinical Microbiology and Applied Technology, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Claude Férec
- Univ Brest, Inserm, EFS, Brest, France.,Service de Génétique Médicale, CHRU Brest, Brest, France
| | - Pornlada Nuchnoi
- Center of Research and Innovation, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand.,Department of Clinical Microscopy, Faculty of Medical Technology, Mahidol University, Bangkok, Thailand
| | - Yann Fichou
- Univ Brest, Inserm, EFS, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
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11
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Womack J, Sukumaran A, Li X, Lozovatsky L, Gallagher PG, Seid JE, Finberg KE. Functional characterization of a novel SLC40A1 Arg88Ile mutation in a kindred with familial iron overload treated by phlebotomy. Blood Cells Mol Dis 2020; 87:102532. [PMID: 33385755 DOI: 10.1016/j.bcmd.2020.102532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 10/22/2022]
Affiliation(s)
- Jihad Womack
- Department of Pathology, Yale School of Medicine, 310 Cedar Street, PO Box 208023, New Haven, CT 06520-8023, USA
| | - Abitha Sukumaran
- Department of Pathology, Yale School of Medicine, 310 Cedar Street, PO Box 208023, New Haven, CT 06520-8023, USA
| | - Xiuqi Li
- Department of Pathology, Yale School of Medicine, 310 Cedar Street, PO Box 208023, New Haven, CT 06520-8023, USA
| | - Larisa Lozovatsky
- Department of Pathology, Yale School of Medicine, 310 Cedar Street, PO Box 208023, New Haven, CT 06520-8023, USA
| | - Patrick G Gallagher
- Department of Pathology, Yale School of Medicine, 310 Cedar Street, PO Box 208023, New Haven, CT 06520-8023, USA; Departments of Pediatrics and Genetics, Yale School of Medicine, 333 Cedar St., PO Box 208064, New Haven, CT 06520-8064, USA
| | - Jerome E Seid
- Great Lakes Cancer Management Specialists, 17900 23 Mile Rd Ste 402, Macomb Township, MI 48044, USA
| | - Karin E Finberg
- Department of Pathology, Yale School of Medicine, 310 Cedar Street, PO Box 208023, New Haven, CT 06520-8023, USA.
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12
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Le Tertre M, Ka C, Raud L, Berlivet I, Gourlaouen I, Richard G, Uguen K, Chen JM, Férec C, Fichou Y, Le Gac G. Splicing analysis of SLC40A1 missense variations and contribution to hemochromatosis type 4 phenotypes. Blood Cells Mol Dis 2020; 87:102527. [PMID: 33341511 DOI: 10.1016/j.bcmd.2020.102527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 02/09/2023]
Abstract
Hemochromatosis type 4, or ferroportin disease, is considered as the second leading cause of primary iron overload after HFE-related hemochromatosis. The disease, which is predominantly associated with missense variations in the SLC40A1 gene, is characterized by wide clinical heterogeneity. We tested the possibility that some of the reported missense mutations, despite their positions within exons, cause splicing defects. Fifty-eight genetic variants were selected from the literature based on two criteria: a precise description of the nucleotide change and individual evidence of iron overload. The selected variants were investigated by different in silico prediction tools and prioritized for midigene splicing assays. Of the 15 variations tested in vitro, only two were associated with splicing changes. We confirm that the c.1402G>A transition (p.Gly468Ser) disrupts the exon 7 donor site, leading to the use of an exonic cryptic splicing site and the generation of a truncated reading frame. We observed, for the first time, that the p.Gly468Ser substitution has no effect on the ferroportin iron export function. We demonstrate alternative splicing of exon 5 in different cell lines and show that the c.430A>G (p.Asn144Asp) variant promotes exon 5 inclusion. This could be part of a gain-of-function mechanism. We conclude that splicing mutations rarely contribute to hemochromatosis type 4 phenotypes. An in-depth investigation of exon 5 auxiliary splicing sequences may help to elucidate the mechanism by which splicing regulatory proteins regulate the production of the full length SLC40A1 transcript and to clarify its physiological importance.
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Affiliation(s)
- Marlène Le Tertre
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France; CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, F-29200, France
| | - Chandran Ka
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France; CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, F-29200, France; Laboratory of Excellence GR-Ex, F-75015, France
| | - Loann Raud
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France; Association Gaétan Saleün, F-29200, France
| | | | - Isabelle Gourlaouen
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France; Laboratory of Excellence GR-Ex, F-75015, France
| | | | - Kévin Uguen
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France; CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, F-29200, France
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France; CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, F-29200, France; Association Gaétan Saleün, F-29200, France
| | - Yann Fichou
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France; Laboratory of Excellence GR-Ex, F-75015, France
| | - Gérald Le Gac
- Univ Brest, Inserm, EFS, UMR1078, GGB, F-29200, France; CHRU de Brest, Service de Génétique Médicale et Biologie de la Reproduction, Laboratoire de Génétique Moléculaire et Histocompatibilité, F-29200, France; Laboratory of Excellence GR-Ex, F-75015, France.
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13
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Rodríguez-Palmero A, Schlüter A, Verdura E, Ruiz M, Martínez JJ, Gourlaouen I, Ka C, Lobato R, Casasnovas C, Le Gac G, Fourcade S, Pujol A. A novel hypomorphic splice variant in EIF2B5 gene is associated with mild ovarioleukodystrophy. Ann Clin Transl Neurol 2020; 7:1574-1579. [PMID: 33245593 PMCID: PMC7480926 DOI: 10.1002/acn3.51131] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 06/27/2020] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE To identify the genetic cause in an adult ovarioleukodystrophy patient resistant to diagnosis. METHODS We applied whole-exome sequencing (WES) to a vanishing white matter disease patient associated with premature ovarian failure at 26 years of age. We functionally tested an intronic variant by RT-PCR on patient's peripheral blood mononuclear cells (PBMC) and by minigene splicing assay. RESULTS WES analysis identified two novel variants in the EIF2B5 gene: c.725A > G (p.Tyr242Cys) and an intronic noncanonical mutation (c.1156 + 13G>A). This intronic mutation resulted into generation of various isoforms both in patient's PBMC and in the minigene splicing assay, showing that ~20% residual wild-type isoform is still expressed by the intronic-mutated allele alone, concordant with an hypomorphic effect of this variant. CONCLUSION We report two novel variants in EIF2B5, one of them a noncanonical intronic splice variant, located at a +13 intronic position. This position is mutated only in 0.05% of ClinVar intronic mutations described so far. Furthermore, we illustrate how minigene splicing assay may be advantageous when validating splice-altering variants, in this case highlighting the coexistence of wild-type and mutated forms, probably explaining this patient's milder, late-onset phenotype.
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Affiliation(s)
- Agustí Rodríguez-Palmero
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Spain.,Pediatrics Department, University Hospital Germans Trias i Pujol, Badalona, 08916, Spain
| | - Agatha Schlüter
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Edgard Verdura
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Montserrat Ruiz
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Juan José Martínez
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | | | - Chandran Ka
- INSERM U1078, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Laboratoire de Génétique Moleculaire et Histocompatibilité, CHRU de Brest, Hôpital Morvan, Brest, France
| | - Ricardo Lobato
- Neurology Department, Hospital Universitario Infanta Sofía, San Sebastián de los Reyes, 28703, Spain
| | - Carlos Casasnovas
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain.,Neuromuscular Unit, Neurology Department, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, 08908, Spain
| | - Gérald Le Gac
- INSERM U1078, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Laboratoire de Génétique Moleculaire et Histocompatibilité, CHRU de Brest, Hôpital Morvan, Brest, France.,Université Bretagne Loire, Université de Bretagne Occidentale, IBSAM, Brest, France
| | - Stéphane Fourcade
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Aurora Pujol
- Neurometabolic Diseases Laboratory, Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, 08908, Spain.,Center for Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain.,Catalan Institution of Research and Advanced Studies (ICREA), Barcelona, Spain
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14
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Billesbølle CB, Azumaya CM, Kretsch RC, Powers AS, Gonen S, Schneider S, Arvedson T, Dror RO, Cheng Y, Manglik A. Structure of hepcidin-bound ferroportin reveals iron homeostatic mechanisms. Nature 2020; 586:807-811. [PMID: 32814342 PMCID: PMC7906036 DOI: 10.1038/s41586-020-2668-z] [Citation(s) in RCA: 157] [Impact Index Per Article: 39.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 07/15/2020] [Indexed: 01/01/2023]
Abstract
The serum iron level in humans is tightly controlled by the action of the hormone hepcidin on the iron efflux transporter ferroportin. Hepcidin regulates iron absorption and recycling by inducing ferroportin internalization and degradation1. Aberrant ferroportin activity can lead to diseases of iron overload, like hemochromatosis, or iron limitation anemias2. Here, we determined cryogenic electron microscopy (cryo-EM) structures of ferroportin in lipid nanodiscs, both in the apo state and in complex with cobalt, an iron mimetic, and hepcidin. These structures and accompanying molecular dynamics simulations identify two metal binding sites within the N- and C-domains of ferroportin. Hepcidin binds ferroportin in an outward-open conformation and completely occludes the iron efflux pathway to inhibit transport. The carboxy-terminus of hepcidin directly contacts the divalent metal in the ferroportin C-domain. We further show that hepcidin binding to ferroportin is coupled to iron binding, with an 80-fold increase in hepcidin affinity in the presence of iron. These results suggest a model for hepcidin regulation of ferroportin, where only iron loaded ferroportin molecules are targeted for degradation. More broadly, our structural and functional insights are likely to enable more targeted manipulation of the hepcidin-ferroportin axis in disorders of iron homeostasis.
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Affiliation(s)
- Christian B Billesbølle
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA
| | - Caleigh M Azumaya
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA
| | - Rachael C Kretsch
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Biophysics Program, Stanford University, Stanford, CA, USA
| | - Alexander S Powers
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Shane Gonen
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA.,Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA.,Department of Molecular Biology and Biochemistry, University of California, Irvine, Biological Sciences III, Irvine, CA, USA
| | - Simon Schneider
- Institute of Biochemistry, Goethe University Frankfurt, Max-von-Laue-Straße 9, Frankfurt am Main, Germany
| | - Tara Arvedson
- Department of Oncology Research, Amgen Inc., South San Francisco, CA, USA
| | - Ron O Dror
- Department of Computer Science, Stanford University, Stanford, CA, USA.,Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA, USA.,Department of Structural Biology, Stanford University School of Medicine, Stanford, CA, USA.,Institute for Computational and Mathematical Engineering, Stanford University, Stanford, CA, USA.,Biophysics Program, Stanford University, Stanford, CA, USA
| | - Yifan Cheng
- Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, CA, USA. .,Howard Hughes Medical Institute, University of California San Francisco, San Francisco, CA, USA.
| | - Aashish Manglik
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, CA, USA. .,Department of Anesthesia and Perioperative Care, University of California, San Francisco, San Francisco, CA, USA.
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15
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Barbagiovanni G, Gabriele M, Testa G. KMT2B and Neuronal Transdifferentiation: Bridging Basic Chromatin Mechanisms to Disease Actionability. Neurosci Insights 2020; 15:2633105520928068. [PMID: 32596666 PMCID: PMC7297493 DOI: 10.1177/2633105520928068] [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: 04/16/2020] [Accepted: 04/21/2020] [Indexed: 11/30/2022] Open
Abstract
The role of bona fide epigenetic regulators in the process of neuronal transdifferentiation was until recently largely uncharacterized, despite their key role in the physiological processes of neural fate acquisition and maintenance. In this commentary, we describe the main findings of our recent paper “KMT2B is selectively required for neuronal transdifferentiation, and its loss exposes dystonia candidate genes,” where we investigated the role of this histone H3K4 methyltransferase during mouse embryonic fibroblasts (MEFs) to induced neuronal cells (iNs) direct conversion. Indeed, Kmt2b–/– MEFs, transduced with three neuronal-specific transcription factors (TFs), Brn2, Ascl1, and Myt1l, show lower transdifferentiation efficiency, defective iN maturation, and augmented alternative cell fates acquisition, with respect to controls. Here, we went beyond the data, hypothesizing how KMT2B executes its fundamental role. In particular, we supposed that MYT1L, which has been proven to be fundamental for iN maturation and the switch-off of alternative cell fates, directly or indirectly needs KMT2B. Indeed, KMT2B could be important both to make MYT1L-target genes accessible, because MYT1L is not a pioneer TF and preferentially binds to open chromatin, and to activate MYT1L-downstream genes.
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Affiliation(s)
- Giulia Barbagiovanni
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy
| | - Michele Gabriele
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy.,Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Giuseppe Testa
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, Milan, Italy.,Department of Oncology and Haemato-Oncology, University of Milan, Milan, Italy.,Human Technopole, Milan, Italy
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16
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Type 4B hereditary hemochromatosis due to heterozygous p.D157A mutation in SLC40A1 complicated with hypopituitarism. Med Mol Morphol 2020; 54:60-67. [PMID: 32607777 DOI: 10.1007/s00795-020-00259-1] [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: 04/16/2020] [Accepted: 06/13/2020] [Indexed: 10/24/2022]
Abstract
Hemochromatosis is a clinical syndrome characterized by iron overload in various organs. We present here a case of type 4 hereditary hemochromatosis due to heterozygous mutation in SLC40A1 gene (p.D157A). SLC40A1 encodes ferroportin, a macromolecule only known as iron exporter from mammalian cells. He first presented symptoms correlated with hypopituitarism. Furthermore, marked hyperferritinemia and high transferrin saturation were revealed in combination with the findings of iron overload in the liver, spleen and pituitary gland by computed tomography and magnetic resonance imaging. Liver biopsy revealed iron deposition in both hepatocytes and Kupffer cells. SLC40A1 mutations are considered to cause wide heterogeneity by various ferroportin mutations. Thus, clinicopathological examinations seem to be very important for diagnosing phenotype of type 4 hemochromatosis in addition to the gene analysis. We diagnosed him as type 4B hereditary hemochromatosis (ferroportin-associated hemochromatosis) by the findings of high transferrin saturation and iron deposition in hepatocytes, and then started iron chelating treatment. We should suspect the possibility of hereditary hemochromatosis even in Japanese with severe iron overload. Although the same mutation in SLC40A1 gene (p.D157A) had been reported to cause "loss of function" phenotype, we considered that the mutation of our case caused "gain of function" phenotype.
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17
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Barbagiovanni G, Germain PL, Zech M, Atashpaz S, Lo Riso P, D'Antonio-Chronowska A, Tenderini E, Caiazzo M, Boesch S, Jech R, Haslinger B, Broccoli V, Stewart AF, Winkelmann J, Testa G. KMT2B Is Selectively Required for Neuronal Transdifferentiation, and Its Loss Exposes Dystonia Candidate Genes. Cell Rep 2019; 25:988-1001. [PMID: 30355503 PMCID: PMC6218204 DOI: 10.1016/j.celrep.2018.09.067] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2017] [Revised: 08/01/2018] [Accepted: 09/19/2018] [Indexed: 12/11/2022] Open
Abstract
Transdifferentiation of fibroblasts into induced neuronal cells (iNs) by the neuron-specific transcription factors Brn2, Myt1l, and Ascl1 is a paradigmatic example of inter-lineage conversion across epigenetically distant cells. Despite tremendous progress regarding the transcriptional hierarchy underlying transdifferentiation, the enablers of the concomitant epigenome resetting remain to be elucidated. Here, we investigated the role of KMT2A and KMT2B, two histone H3 lysine 4 methylases with cardinal roles in development, through individual and combined inactivation. We found that Kmt2b, whose human homolog's mutations cause dystonia, is selectively required for iN conversion through suppression of the alternative myocyte program and induction of neuronal maturation genes. The identification of KMT2B-vulnerable targets allowed us, in turn, to expose, in a cohort of 225 patients, 45 unique variants in 39 KMT2B targets, which represent promising candidates to dissect the molecular bases of dystonia.
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Affiliation(s)
- Giulia Barbagiovanni
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, 20139 Milan, Italy
| | - Pierre-Luc Germain
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, 20139 Milan, Italy
| | - Michael Zech
- Institut für Neurogenomik, Helmholtz Zentrum München, 85764 Munich, Germany; Klinik und Poliklinik für Neurologie, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
| | - Sina Atashpaz
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, 20139 Milan, Italy
| | - Pietro Lo Riso
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, 20139 Milan, Italy
| | | | - Erika Tenderini
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, 20139 Milan, Italy
| | | | - Sylvia Boesch
- Department of Neurology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Robert Jech
- Department of Neurology and Center of Clinical Neuroscience, First Faculty of Medicine, Charles University and General Faculty Hospital, 12821 Prague, Czech Republic
| | - Bernhard Haslinger
- Klinik und Poliklinik für Neurologie, Klinikum rechts der Isar, Technische Universität München, 81675 Munich, Germany
| | - Vania Broccoli
- San Raffaele Scientific Institute, 20132 Milan, Italy; National Research Council (CNR), Institute of Neuroscience, 20129 Milan, Italy
| | - Adrian Francis Stewart
- Genomics, Biotechnology Center, Center for Molecular and Cellular Bioengineering, Technische Universität Dresden, 01069 Dresden, Germany
| | - Juliane Winkelmann
- Institut für Neurogenomik, Helmholtz Zentrum München, 85764 Munich, Germany; Lehrstuhl für Neurogenetik und Institut für Humangenetik, Technische Universität München, 81675 Munich, Germany; Munich Cluster for Systems Neurology, SyNergy, 81829 Munich, Germany
| | - Giuseppe Testa
- Department of Experimental Oncology, IEO, European Institute of Oncology IRCCS, 20139 Milan, Italy; Department of Oncology and Hemato-Oncology, University of Milan, 20122 Milan, Italy.
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18
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Guellec J, Elbahnsi A, Le Tertre M, Uguen K, Gourlaouen I, Férec C, Ka C, Callebaut I, Le Gac G. Molecular model of the ferroportin intracellular gate and implications for the human iron transport cycle and hemochromatosis type 4A. FASEB J 2019; 33:14625-14635. [PMID: 31690120 DOI: 10.1096/fj.201901857r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Ferroportin 1 (FPN1) is a major facilitator superfamily transporter that is essential for proper maintenance of human iron homeostasis at the systemic and cellular level. FPN1 dysfunction leads to the progressive accumulation of iron in reticuloendothelial cells, causing hemochromatosis type 4A (or ferroportin disease), an autosomal dominant disorder that displays large phenotypic heterogeneity. Although crystal structures have unveiled the outward- and inward-facing conformations of the bacterial homolog Bdellovibrio bacteriovorus Fpn (or Bd2019) and calcium has recently been identified as an essential cofactor, our molecular understanding of the iron transport mechanism remains incomplete. Here, we used a combination of molecular modeling, molecular dynamics simulations, and Ala site-directed mutagenesis, followed by complementary in vitro functional analyses, to explore the structural architecture of the human FPN1 intracellular gate. We reveal an interdomain network that involves 5 key amino acids and is likely very important for stability of the iron exporter facing the extracellular milieu. We also identify inter- and intradomain interactions that rely on the 2 Asp84 and Asn174 critical residues and do not exist in the bacterial homolog. These interactions are thought to play an important role in the modulation of conformational changes during the transport cycle. We interpret these results in the context of hemochromatosis type 4A, reinforcing the idea that different categories of loss-of-function mutations exist. Our findings provide an unprecedented view of the human FPN1 outward-facing structure and the particular function of the so-called "gating residues" in the mechanism of iron export.-Guellec, J., Elbahnsi, A., Le Tertre, M., Uguen, K., Gourlaouen, I., Férec, C., Ka, C., Callebaut, I., Le Gac, G. Molecular model of the ferroportin intracellular gate and implications for the human iron transport cycle and hemochromatosis type 4A.
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Affiliation(s)
- Julie Guellec
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Association Gaetan Saleun, Brest, France
| | - Ahmad Elbahnsi
- Muséum National d'Histoire Naturelle, UMR Centre National de la Recherche Scientifique (CNRS) 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, Paris, France
| | - Marlène Le Tertre
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and
| | - Kévin Uguen
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and
| | - Isabelle Gourlaouen
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France
| | - Claude Férec
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Association Gaetan Saleun, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and
| | - Chandran Ka
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and.,Laboratory of Excellence Laboratory of Excellence (GR-Ex), Paris, France
| | - Isabelle Callebaut
- Muséum National d'Histoire Naturelle, UMR Centre National de la Recherche Scientifique (CNRS) 7590, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, Paris, France
| | - Gérald Le Gac
- INSERM Unité Mixte de Recherche (UMR) 1078, Etablissement Français du Sang-Bretagne, Institut Brestois Santé-Agro-Matière, Université Bretagne Loire-Université de Brest, Brest, France.,Service de Génétique Médicale, Centre Hospitalier Régional et Universitaire (CHRU) de Brest, Hôpital Morvan, Brest, France; and.,Laboratory of Excellence Laboratory of Excellence (GR-Ex), Paris, France
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19
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Vlasveld LT, Swinkels DW. Loss-of-function ferroportin disease: novel mechanistic insights and unanswered questions. Haematologica 2019; 103:1753-1755. [PMID: 30381414 DOI: 10.3324/haematol.2018.203315] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Affiliation(s)
- L Tom Vlasveld
- Department of Internal Medicine, Haaglanden Medical Center, Location Bronovo, The Hague
| | - Dorine W Swinkels
- Translational Metabolic Laboratory, Department of Laboratory Medicine, Radboud University Medical Center, Nijmegen, the Netherlands
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20
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Vlasveld LT, Janssen R, Bardou-Jacquet E, Venselaar H, Hamdi-Roze H, Drakesmith H, Swinkels DW. Twenty Years of Ferroportin Disease: A Review or An Update of Published Clinical, Biochemical, Molecular, and Functional Features. Pharmaceuticals (Basel) 2019; 12:ph12030132. [PMID: 31505869 PMCID: PMC6789780 DOI: 10.3390/ph12030132] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 08/14/2019] [Accepted: 08/20/2019] [Indexed: 12/14/2022] Open
Abstract
Iron overloading disorders linked to mutations in ferroportin have diverse phenotypes in vivo, and the effects of mutations on ferroportin in vitro range from loss of function (LOF) to gain of function (GOF) with hepcidin resistance. We reviewed 359 patients with 60 ferroportin variants. Overall, macrophage iron overload and low/normal transferrin saturation (TSAT) segregated with mutations that caused LOF, while GOF mutations were linked to high TSAT and parenchymal iron accumulation. However, the pathogenicity of individual variants is difficult to establish due to the lack of sufficiently reported data, large inter-assay variability of functional studies, and the uncertainty associated with the performance of available in silico prediction models. Since the phenotypes of hepcidin-resistant GOF variants are indistinguishable from the other types of hereditary hemochromatosis (HH), these variants may be categorized as ferroportin-associated HH, while the entity ferroportin disease may be confined to patients with LOF variants. To further improve the management of ferroportin disease, we advocate for a global registry, with standardized clinical analysis and validation of the functional tests preferably performed in human-derived enterocytic and macrophagic cell lines. Moreover, studies are warranted to unravel the definite structure of ferroportin and the indispensable residues that are essential for functionality.
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Affiliation(s)
- L Tom Vlasveld
- Department of Internal Medicine, Haaglanden MC-Bronovo, 2597AX The Hague, The Netherlands
| | - Roel Janssen
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands
| | - Edouard Bardou-Jacquet
- Liver Diseases Department, French Reference Centre for Rare Iron Overload Diseases of Genetic Origin, University Hospital Pontchaillou, 35033 Rennes, France
| | - Hanka Venselaar
- Centre for Molecular and Biomolecular Informatics, Radboud Institute for Molecular Life Sciences, Radboud, University Medical Center, P.O. Box 9191, 6500 HB Nijmegen, The Netherlands
| | - Houda Hamdi-Roze
- Molecular Genetics Department, French Reference Centre for Rare Iron Overload Diseases of Genetic Origin, University Hospital Pontchaillou, 35033 Rennes, France
| | - Hal Drakesmith
- MRC Human Immunology Unit, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford OX39DS, UK
| | - Dorine W Swinkels
- Department of Laboratory Medicine, Translational Metabolic Laboratory, Radboud University Medical Center, P.O. Box 9101, 6500 HB Nijmegen, The Netherlands.
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21
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Leman R, Gaildrat P, Le Gac G, Ka C, Fichou Y, Audrezet MP, Caux-Moncoutier V, Caputo SM, Boutry-Kryza N, Léone M, Mazoyer S, Bonnet-Dorion F, Sevenet N, Guillaud-Bataille M, Rouleau E, Bressac-de Paillerets B, Wappenschmidt B, Rossing M, Muller D, Bourdon V, Revillon F, Parsons MT, Rousselin A, Davy G, Castelain G, Castéra L, Sokolowska J, Coulet F, Delnatte C, Férec C, Spurdle AB, Martins A, Krieger S, Houdayer C. Novel diagnostic tool for prediction of variant spliceogenicity derived from a set of 395 combined in silico/in vitro studies: an international collaborative effort. Nucleic Acids Res 2019; 46:7913-7923. [PMID: 29750258 PMCID: PMC6125621 DOI: 10.1093/nar/gky372] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Accepted: 04/27/2018] [Indexed: 12/17/2022] Open
Abstract
Variant interpretation is the key issue in molecular diagnosis. Spliceogenic variants exemplify this issue as each nucleotide variant can be deleterious via disruption or creation of splice site consensus sequences. Consequently, reliable in silico prediction of variant spliceogenicity would be a major improvement. Thanks to an international effort, a set of 395 variants studied at the mRNA level and occurring in 5′ and 3′ consensus regions (defined as the 11 and 14 bases surrounding the exon/intron junction, respectively) was collected for 11 different genes, including BRCA1, BRCA2, CFTR and RHD, and used to train and validate a new prediction protocol named Splicing Prediction in Consensus Elements (SPiCE). SPiCE combines in silico predictions from SpliceSiteFinder-like and MaxEntScan and uses logistic regression to define optimal decision thresholds. It revealed an unprecedented sensitivity and specificity of 99.5 and 95.2%, respectively, and the impact on splicing was correctly predicted for 98.8% of variants. We therefore propose SPiCE as the new tool for predicting variant spliceogenicity. It could be easily implemented in any diagnostic laboratory as a routine decision making tool to help geneticists to face the deluge of variants in the next-generation sequencing era. SPiCE is accessible at (https://sourceforge.net/projects/spicev2-1/).
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Affiliation(s)
- Raphaël Leman
- Laboratoire de Biologie Clinique et Oncologique, Centre François Baclesse, 14000 Caen, France.,Inserm U1245 Genomics and Personalized Medecine in Cancer and Neurological Disorders, Normandie Univ, UNIROUEN, Normandy Centre for Genomic and Personalized Medicine, 76031 Rouen, France.,Normandie Univ, UNICAEN, 14000 Caen, France
| | - Pascaline Gaildrat
- Inserm U1245 Genomics and Personalized Medecine in Cancer and Neurological Disorders, Normandie Univ, UNIROUEN, Normandy Centre for Genomic and Personalized Medicine, 76031 Rouen, France
| | - Gérald Le Gac
- Inserm UMR1078, Genetics, Functional Genomics and Biotechnology, Université de Bretagne Occidentale, 29200 Brest, France
| | - Chandran Ka
- Inserm UMR1078, Genetics, Functional Genomics and Biotechnology, Université de Bretagne Occidentale, 29200 Brest, France
| | - Yann Fichou
- Inserm UMR1078, Genetics, Functional Genomics and Biotechnology, Université de Bretagne Occidentale, 29200 Brest, France
| | - Marie-Pierre Audrezet
- Inserm UMR1078, Genetics, Functional Genomics and Biotechnology, Université de Bretagne Occidentale, 29200 Brest, France
| | - Virginie Caux-Moncoutier
- Inserm U830, Institut Curie Centre de Recherches, 75005 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75005 Paris, France.,Service de Génétique, Institut Curie, 75005 Paris, France
| | | | - Nadia Boutry-Kryza
- Unité Mixte de Génétique Constitutionnelle des Cancers Fréquents, Hospices Civils de Lyon, 69000 Lyon, France
| | - Mélanie Léone
- Unité Mixte de Génétique Constitutionnelle des Cancers Fréquents, Hospices Civils de Lyon, 69000 Lyon, France
| | - Sylvie Mazoyer
- Lyon Neuroscience Research Center-CRNL, Inserm U1028, CNRS UMR 5292, University of Lyon, 69008 Lyon, France
| | - Françoise Bonnet-Dorion
- Inserm U916, Département de Pathologie, Laboratoire de Génétique Constitutionnelle, Institut Bergonié, 33000 Bordeaux, France
| | - Nicolas Sevenet
- Inserm U916, Département de Pathologie, Laboratoire de Génétique Constitutionnelle, Institut Bergonié, 33000 Bordeaux, France
| | | | - Etienne Rouleau
- Gustave Roussy, Université Paris-Saclay, Département de Biopathologie, 94805 Villejuif, France
| | | | - Barbara Wappenschmidt
- Division of Molecular Gynaeco-Oncology, Department of Gynaecology and Obstetrics, University Hospital of Cologne, 50937 Cologne, Germany
| | - Maria Rossing
- Centre for Genomic Medicine, Rigshospitalet, University of Copenhagen, 1017 Copenhagen, Denmark
| | - Danielle Muller
- Laboratoire d'Oncogénétique, Centre Paul Strauss, 67000 Strasbourg, France
| | - Violaine Bourdon
- Laboratoire d'Oncogénétique Moléculaire, Institut Paoli-Calmettes, 13009 Marseille, France
| | - Françoise Revillon
- Laboratoire d'Oncogénétique Moléculaire Humaine, Centre Oscar Lambret, 59000 Lille, France
| | - Michael T Parsons
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, 4006 Herston, Queensland, Australia
| | - Antoine Rousselin
- Laboratoire de Biologie Clinique et Oncologique, Centre François Baclesse, 14000 Caen, France.,Inserm U1245 Genomics and Personalized Medecine in Cancer and Neurological Disorders, Normandie Univ, UNIROUEN, Normandy Centre for Genomic and Personalized Medicine, 76031 Rouen, France
| | - Grégoire Davy
- Laboratoire de Biologie Clinique et Oncologique, Centre François Baclesse, 14000 Caen, France.,Inserm U1245 Genomics and Personalized Medecine in Cancer and Neurological Disorders, Normandie Univ, UNIROUEN, Normandy Centre for Genomic and Personalized Medicine, 76031 Rouen, France
| | - Gaia Castelain
- Inserm U1245 Genomics and Personalized Medecine in Cancer and Neurological Disorders, Normandie Univ, UNIROUEN, Normandy Centre for Genomic and Personalized Medicine, 76031 Rouen, France
| | - Laurent Castéra
- Laboratoire de Biologie Clinique et Oncologique, Centre François Baclesse, 14000 Caen, France.,Inserm U1245 Genomics and Personalized Medecine in Cancer and Neurological Disorders, Normandie Univ, UNIROUEN, Normandy Centre for Genomic and Personalized Medicine, 76031 Rouen, France
| | | | - Florence Coulet
- Service de génétique, Hôpital Pitié Salpétrière, AP-HP, 75013 Paris, France
| | - Capucine Delnatte
- Laboratoire de génétique moléculaire, CHU Nantes, 44000 Nantes, France
| | - Claude Férec
- Inserm UMR1078, Genetics, Functional Genomics and Biotechnology, Université de Bretagne Occidentale, 29200 Brest, France
| | - Amanda B Spurdle
- Department of Genetics and Computational Biology, QIMR Berghofer Medical Research Institute, 4006 Herston, Queensland, Australia
| | - Alexandra Martins
- Inserm U1245 Genomics and Personalized Medecine in Cancer and Neurological Disorders, Normandie Univ, UNIROUEN, Normandy Centre for Genomic and Personalized Medicine, 76031 Rouen, France
| | - Sophie Krieger
- Laboratoire de Biologie Clinique et Oncologique, Centre François Baclesse, 14000 Caen, France.,Inserm U1245 Genomics and Personalized Medecine in Cancer and Neurological Disorders, Normandie Univ, UNIROUEN, Normandy Centre for Genomic and Personalized Medicine, 76031 Rouen, France.,Normandie Univ, UNICAEN, 14000 Caen, France
| | - Claude Houdayer
- Inserm U830, Institut Curie Centre de Recherches, 75005 Paris, France.,Université Paris Descartes, Sorbonne Paris Cité, 75005 Paris, France.,Service de Génétique, Institut Curie, 75005 Paris, France
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22
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Raud L, Ka C, Gourlaouen I, Callebaut I, Férec C, Le Gac G, Fichou Y. Functional analysis of novelRHDvariants: splicing disruption is likely to be a common mechanism of variant D phenotype. Transfusion 2019; 59:1367-1375. [DOI: 10.1111/trf.15210] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 11/22/2018] [Accepted: 12/06/2018] [Indexed: 02/01/2023]
Affiliation(s)
- Loann Raud
- UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies"; INSERM, EFS, Université de Brest, IBSAM, CHU de Brest; Brest France
- Laboratory of Excellence GR-Ex; Paris France
| | - Chandran Ka
- UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies"; INSERM, EFS, Université de Brest, IBSAM, CHU de Brest; Brest France
- Laboratory of Excellence GR-Ex; Paris France
| | - Isabelle Gourlaouen
- UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies"; INSERM, EFS, Université de Brest, IBSAM, CHU de Brest; Brest France
- Laboratory of Excellence GR-Ex; Paris France
| | - Isabelle Callebaut
- IMPMC, Sorbonne Universités - UMR CNRS 7590, UPMC Univ Paris 06, Muséum d'Histoire Naturelle, IRD UMR 206; Paris France
| | - Claude Férec
- UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies"; INSERM, EFS, Université de Brest, IBSAM, CHU de Brest; Brest France
- Laboratory of Excellence GR-Ex; Paris France
| | - Gérald Le Gac
- UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies"; INSERM, EFS, Université de Brest, IBSAM, CHU de Brest; Brest France
- Laboratory of Excellence GR-Ex; Paris France
| | - Yann Fichou
- UMR1078 "Génétique, Génomique Fonctionnelle et Biotechnologies"; INSERM, EFS, Université de Brest, IBSAM, CHU de Brest; Brest France
- Laboratory of Excellence GR-Ex; Paris France
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23
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Choi EK, Nguyen TT, Iwase S, Seo YA. Ferroportin disease mutations influence manganese accumulation and cytotoxicity. FASEB J 2019; 33:2228-2240. [PMID: 30247984 PMCID: PMC6338638 DOI: 10.1096/fj.201800831r] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 08/27/2018] [Indexed: 12/12/2022]
Abstract
Hemochromatosis is a frequent genetic disorder, characterized by the accumulation of excess iron across tissues. Mutations in the FPN1 gene, encoding a cell surface iron exporter [ferroportin (Fpn)], are responsible for hemochromatosis type 4, also known as ferroportin disease. Recently, Fpn has been implicated in the regulation of manganese (Mn), another essential nutrient required for numerous cellular enzymes. However, the roles of Fpn in Mn regulation remain ill-defined, and the impact of disease mutations on cellular Mn levels is unknown. Here, we provide evidence that Fpn can export Mn from cells into extracellular space. Fpn seems to play protective roles in Mn-induced cellular toxicity and oxidative stress. Finally, disease mutations interfere with the role of Fpn in controlling Mn levels as well as the stability of Fpn. These results define the function of Fpn as an exporter of both iron and Mn and highlight the potential involvement of Mn dysregulation in ferroportin disease.-Choi, E.-K., Nguyen, T.-T., Iwase, S., Seo, Y. A. Ferroportin disease mutations influence manganese accumulation and cytotoxicity.
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Affiliation(s)
- Eun-Kyung Choi
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA; and
| | - Trang-Tiffany Nguyen
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA; and
| | - Shigeki Iwase
- Department of Human Genetics, University of Michigan, Ann Arbor, Michigan, USA
| | - Young Ah Seo
- Department of Nutritional Sciences, University of Michigan School of Public Health, Ann Arbor, Michigan, USA; and
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24
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Ferroportin deficiency in erythroid cells causes serum iron deficiency and promotes hemolysis due to oxidative stress. Blood 2018; 132:2078-2087. [PMID: 30213870 DOI: 10.1182/blood-2018-04-842997] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 09/06/2018] [Indexed: 02/07/2023] Open
Abstract
Ferroportin (FPN), the only known vertebrate iron exporter, transports iron from intestinal, splenic, and hepatic cells into the blood to provide iron to other tissues and cells in vivo. Most of the circulating iron is consumed by erythroid cells to synthesize hemoglobin. Here we found that erythroid cells not only consumed large amounts of iron, but also returned significant amounts of iron to the blood. Erythroblast-specific Fpn knockout (Fpn KO) mice developed lower serum iron levels in conjunction with tissue iron overload and increased FPN expression in spleen and liver without changing hepcidin levels. Our results also showed that Fpn KO mice, which suffer from mild hemolytic anemia, were sensitive to phenylhydrazine-induced oxidative stress but were able to tolerate iron deficiency upon exposure to a low-iron diet and phlebotomy, supporting that the anemia of Fpn KO mice resulted from erythrocytic iron overload and resulting oxidative injury rather than a red blood cell (RBC) production defect. Moreover, we found that the mean corpuscular volume (MCV) values of gain-of-function FPN mutation patients were positively associated with serum transferrin saturations, whereas MCVs of loss-of-function FPN mutation patients were not, supporting that erythroblasts donate iron to blood through FPN in response to serum iron levels. Our results indicate that FPN of erythroid cells plays an unexpectedly essential role in maintaining systemic iron homeostasis and protecting RBCs from oxidative stress, providing insight into the pathophysiology of FPN diseases.
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25
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Ka C, Guellec J, Pepermans X, Kannengiesser C, Ged C, Wuyts W, Cassiman D, de Ledinghen V, Varet B, de Kerguenec C, Oudin C, Gourlaouen I, Lefebvre T, Férec C, Callebaut I, Le Gac G. The SLC40A1 R178Q mutation is a recurrent cause of hemochromatosis and is associated with a novel pathogenic mechanism. Haematologica 2018; 103:1796-1805. [PMID: 30002125 PMCID: PMC6278975 DOI: 10.3324/haematol.2018.189845] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2018] [Accepted: 07/06/2018] [Indexed: 12/29/2022] Open
Abstract
Hemochromatosis type 4 is one of the most common causes of primary iron overload, after HFE-related hemochromatosis. It is an autosomal dominant disorder, primarily due to missense mutations in SLC40A1. This gene encodes ferroportin 1 (FPN1), which is the sole iron export protein reported in mammals. Not all heterozygous missense mutations in SLC40A1 are disease-causing. Due to phenocopies and an increased demand for genetic testing, rare SLC40A1 variations are fortuitously observed in patients with a secondary cause of hyperferritinemia. Structure/function analysis is the most effective way of establishing causality when clinical and segregation data are lacking. It can also provide important insights into the mechanism of iron egress and FPN1 regulation by hepcidin. The present study aimed to determine the pathogenicity of the previously reported p.Arg178Gln variant. We present the biological, clinical, histological and radiological findings of 22 patients from six independent families of French, Belgian or Iraqi decent. Despite phenotypic variability, all patients with p.Arg178Gln had elevated serum ferritin concentrations and normal to low transferrin saturation levels. In vitro experiments demonstrated that the p.Arg178Gln mutant reduces the ability of FPN1 to export iron without causing protein mislocalization. Based on a comparative model of the 3D structure of human FPN1 in an outward facing conformation, we argue that p.Arg178 is part of an interaction network modulating the conformational changes required for iron transport. We conclude that p.Arg178Gln represents a new category of loss-of-function mutations and that the study of “gating residues” is necessary in order to fully understand the action mechanism of FPN1.
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Affiliation(s)
- Chandran Ka
- UMR1078, INSERM, Université Bretagne Loire - Université de Bretagne Occidentale, Etablissement Français du Sang - Bretagne, Institut Brestois Santé-Agro-Matière, Brest, France.,Laboratoire de Génétique Moléculaire et Histocompatibilité, CHRU de Brest, Hôpital Morvan, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Julie Guellec
- UMR1078, INSERM, Université Bretagne Loire - Université de Bretagne Occidentale, Etablissement Français du Sang - Bretagne, Institut Brestois Santé-Agro-Matière, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France.,Association Gaetan Saleun, Brest, France
| | - Xavier Pepermans
- Center for Human Genetics, University Hospital of St-Luc, Brussels, Belgium
| | - Caroline Kannengiesser
- Laboratory of Excellence GR-Ex, Paris, France.,UMR1149, INSERM, Centre de Recherche sur l'Inflammation, Université Paris Diderot, AP-HP, Hôpital Bichat, Département de Génétique, France.,On behalf of the French National Network for the Molecular Diagnosis of Inherited Iron Overload Disorders (J. Rochette, E. Cadet, C. Kannengiesser, H. Puy, C. Ged, H. de Verneuil, G. Le Gac, C. Férec, S. Pissard, V. Gérolami), Brest, France
| | - Cécile Ged
- On behalf of the French National Network for the Molecular Diagnosis of Inherited Iron Overload Disorders (J. Rochette, E. Cadet, C. Kannengiesser, H. Puy, C. Ged, H. de Verneuil, G. Le Gac, C. Férec, S. Pissard, V. Gérolami), Brest, France.,INSERM U1035, BMGIC, CHU de Bordeaux, Laboratoire de Biochimie et Biologie Moléculaire, France
| | - Wim Wuyts
- Department of Medical Genetics, University and University Hospital of Antwerp, Edegem, Belgium
| | - David Cassiman
- Department of Gastroenterology-Hepatology and Metabolic Center, University Hospital of Leuven, Belgium
| | - Victor de Ledinghen
- Department of Gastroenterology and Digestive Oncology, University Hospital of Bordeaux, France
| | - Bruno Varet
- Université Paris Descartes et AP-HP, Hôpital Necker, Service d'Hématologie, France
| | | | - Claire Oudin
- UMR1149, INSERM, Centre de Recherche sur l'Inflammation, Université Paris Diderot, AP-HP, Hôpital Bichat, Département de Génétique, France
| | - Isabelle Gourlaouen
- UMR1078, INSERM, Université Bretagne Loire - Université de Bretagne Occidentale, Etablissement Français du Sang - Bretagne, Institut Brestois Santé-Agro-Matière, Brest, France.,Laboratory of Excellence GR-Ex, Paris, France
| | - Thibaud Lefebvre
- UMR1149, INSERM, Centre de Recherche sur l'Inflammation, Université Paris Diderot, AP-HP, Hôpital Bichat, Département de Génétique, France
| | - Claude Férec
- UMR1078, INSERM, Université Bretagne Loire - Université de Bretagne Occidentale, Etablissement Français du Sang - Bretagne, Institut Brestois Santé-Agro-Matière, Brest, France.,Laboratoire de Génétique Moléculaire et Histocompatibilité, CHRU de Brest, Hôpital Morvan, France.,On behalf of the French National Network for the Molecular Diagnosis of Inherited Iron Overload Disorders (J. Rochette, E. Cadet, C. Kannengiesser, H. Puy, C. Ged, H. de Verneuil, G. Le Gac, C. Férec, S. Pissard, V. Gérolami), Brest, France
| | - Isabelle Callebaut
- UMR7590, CNRS, Sorbonne Universités, Université Pierre et Marie Curie-Paris, France
| | - Gérald Le Gac
- UMR1078, INSERM, Université Bretagne Loire - Université de Bretagne Occidentale, Etablissement Français du Sang - Bretagne, Institut Brestois Santé-Agro-Matière, Brest, France .,Laboratoire de Génétique Moléculaire et Histocompatibilité, CHRU de Brest, Hôpital Morvan, France.,Laboratory of Excellence GR-Ex, Paris, France.,On behalf of the French National Network for the Molecular Diagnosis of Inherited Iron Overload Disorders (J. Rochette, E. Cadet, C. Kannengiesser, H. Puy, C. Ged, H. de Verneuil, G. Le Gac, C. Férec, S. Pissard, V. Gérolami), Brest, France
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Structure-function analysis of ferroportin defines the binding site and an alternative mechanism of action of hepcidin. Blood 2017; 131:899-910. [PMID: 29237594 DOI: 10.1182/blood-2017-05-786590] [Citation(s) in RCA: 210] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 11/30/2017] [Indexed: 02/07/2023] Open
Abstract
Nonclassical ferroportin disease (FD) is a form of hereditary hemochromatosis caused by mutations in the iron transporter ferroportin (Fpn), resulting in parenchymal iron overload. Fpn is regulated by the hormone hepcidin, which induces Fpn endocytosis and cellular iron retention. We characterized 11 clinically relevant and 5 nonclinical Fpn mutations using stably transfected, inducible isogenic cell lines. All clinical mutants were functionally resistant to hepcidin as a consequence of either impaired hepcidin binding or impaired hepcidin-dependent ubiquitination despite intact hepcidin binding. Mapping the residues onto 2 computational models of the human Fpn structure indicated that (1) mutations that caused ubiquitination-resistance were positioned at helix-helix interfaces, likely preventing the hepcidin-induced conformational change, (2) hepcidin binding occurred within the central cavity of Fpn, (3) hepcidin interacted with up to 4 helices, and (4) hepcidin binding should occlude Fpn and interfere with iron export independently of endocytosis. We experimentally confirmed hepcidin-mediated occlusion of Fpn in the absence of endocytosis in multiple cellular systems: HEK293 cells expressing an endocytosis-defective Fpn mutant (K8R), Xenopus oocytes expressing wild-type or K8R Fpn, and mature human red blood cells. We conclude that nonclassical FD is caused by Fpn mutations that decrease hepcidin binding or hinder conformational changes required for ubiquitination and endocytosis of Fpn. The newly documented ability of hepcidin and its agonists to occlude iron transport may facilitate the development of broadly effective treatments for hereditary iron overload disorders.
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27
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Pietrangelo A. Ferroportin disease: pathogenesis, diagnosis and treatment. Haematologica 2017; 102:1972-1984. [PMID: 29101207 PMCID: PMC5709096 DOI: 10.3324/haematol.2017.170720] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 09/25/2017] [Indexed: 12/14/2022] Open
Abstract
Ferroportin Disease (FD) is an autosomal dominant hereditary iron loading disorder associated with heterozygote mutations of the ferroportin-1 (FPN) gene. It represents one of the commonest causes of genetic hyperferritinemia, regardless of ethnicity. FPN1 transfers iron from the intestine, macrophages and placenta into the bloodstream. In FD, loss-of-function mutations of FPN1 limit but do not impair iron export in enterocytes, but they do severely affect iron transfer in macrophages. This leads to progressive and preferential iron trapping in tissue macrophages, reduced iron release to serum transferrin (i.e. inappropriately low transferrin saturation) and a tendency towards anemia at menarche or after intense bloodletting. The hallmark of FD is marked iron accumulation in hepatic Kupffer cells. Numerous FD-associated mutations have been reported worldwide, with a few occurring in different populations and some more commonly reported (e.g. Val192del, A77D, and G80S). FPN1 polymorphisms also represent the gene variants most commonly responsible for hyperferritinemia in Africans. Differential diagnosis includes mainly hereditary hemochromatosis, the syndrome commonly due to either HFE or TfR2, HJV, HAMP, and, in rare instances, FPN1 itself. Here, unlike FD, hyperferritinemia associates with high transferrin saturation, iron-spared macrophages, and progressive parenchymal cell iron load. Abdominal magnetic resonance imaging (MRI), the key non-invasive diagnostic tool for the diagnosis of FD, shows the characteristic iron loading SSL triad (spleen, spine and liver). A non-aggressive phlebotomy regimen is recommended, with careful monitoring of transferrin saturation and hemoglobin due to the risk of anemia. Family screening is mandatory since siblings and offspring have a 50% chance of carrying the pathogenic mutation.
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Affiliation(s)
- Antonello Pietrangelo
- Center for Hemochromatosis, Department of Internal Medicine II, University of Modena and Reggio Emilia Policlinico, Modena, Italy
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Wallace DF, McDonald CJ, Ostini L, Iser D, Tuckfield A, Subramaniam VN. The dynamics of hepcidin-ferroportin internalization and consequences of a novel ferroportin disease mutation. Am J Hematol 2017; 92:1052-1061. [PMID: 28681497 DOI: 10.1002/ajh.24844] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/29/2017] [Accepted: 06/30/2017] [Indexed: 12/31/2022]
Abstract
The hepcidin-ferroportin axis underlies the pathophysiology of many iron-associated disorders and is a key target for the development of therapeutics for treating iron-associated disorders. The aims of this study were to investigate the dynamics of hepcidin-mediated ferroportin internalization and the consequences of a novel disease-causing mutation on ferroportin function. Specific reagents for ferroportin are limited; we developed and characterized antibodies against the largest extracellular loop of ferroportin and developed a novel cell-based assay for studying hepcidin-ferroportin function. We show that hepcidin-mediated ferroportin internalization is a rapid process and could be induced using low concentrations of hepcidin. Targeted next-generation sequencing utilizing an iron metabolism gene panel developed in our group identified a novel ferroportin p.D84E variant in a patient with iron overload. Wild-type and mutant ferroportin constructs were generated, transfected into HEK293 cells and analysed using an all-in-one flow-cytometry-based assay to study the effects on hepcidin-mediated internalization and iron transport. Consistent with the classical phenotype of ferroportin disease, the p.D84E mutation results in an inability to transport iron and hepcidin insensitivity. These results validate a recently proposed 3D-structural model of ferroportin and highlight the significance of this variant in the structure and function of ferroportin. Our novel ferroportin antibody and assay will be valuable tools for investigating the regulation of hepcidin/ferroportin function and the development of novel approaches for the therapeutic modulation of iron homeostasis.
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Affiliation(s)
- Daniel F. Wallace
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences. Queensland University of Technology (QUT); Brisbane Queensland Australia
- Membrane Transport Laboratory; QIMR Berghofer Medical Research Institute; Brisbane Queensland Australia
| | - Cameron J. McDonald
- Membrane Transport Laboratory; QIMR Berghofer Medical Research Institute; Brisbane Queensland Australia
| | - Lesa Ostini
- Membrane Transport Laboratory; QIMR Berghofer Medical Research Institute; Brisbane Queensland Australia
| | - David Iser
- Department of Gastroenterology; St Vincent's Hospital; Fitzroy Victoria Australia
| | | | - V. Nathan Subramaniam
- Institute of Health and Biomedical Innovation and School of Biomedical Sciences. Queensland University of Technology (QUT); Brisbane Queensland Australia
- Membrane Transport Laboratory; QIMR Berghofer Medical Research Institute; Brisbane Queensland Australia
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29
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Le Tertre M, Ka C, Guellec J, Gourlaouen I, Férec C, Callebaut I, Le Gac G. Deciphering the molecular basis of ferroportin resistance to hepcidin: Structure/function analysis of rare SLC40A1 missense mutations found in suspected hemochromatosis type 4 patients. Transfus Clin Biol 2017; 24:462-467. [PMID: 28826751 DOI: 10.1016/j.tracli.2017.07.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 07/20/2017] [Indexed: 01/25/2023]
Abstract
Genetic medicine applied to the study of hemochromatosis has identified the systemic loop controlling iron homeostasis, centered on hepcidin-ferroportin interaction. Current challenges are to dissect the molecular pathways underlying liver hepcidin synthesis in response to circulatory iron, HFE, TFR2, HJV, TMPRSS6 and BMP6 functions, and to define the major structural elements of hepcidin-ferroportin interaction. We built a first 3D model of human ferroportin structure, using the crystal structure of EmrD, a bacterial drug efflux transporter of the Major Facilitator Superfamily, as template. The model enabled study of disease-associated mutations, and guided mutagenesis experiments to determine the role of conserved residues in protein stability and iron transport. Results revealed novel amino acids that are critical for the iron export function and the hepcidin-mediated inhibition mechanism: for example, tryptophan 42, localized in the extracellular end of the ferroportin pore and involved in both biological functions. Here, we propose a strategy that is not limited to structure analysis, but integrates information from different sources, including human disease-associated mutations and functional in vitro assays. The first major hypothesis of this PhD thesis is that ferroportin resistance to hepcidin relies on different molecular mechanisms that are critical for ferroportin endocytosis, and include at least three fundamental steps: (i) hepcidin binding to ferroportin, (ii) structural reorganization of the N- and C-ter ferroportin lobes, and (iii) ferroportin ubiquitination.
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Affiliation(s)
- M Le Tertre
- Inserm UMR1078, faculté de médecine et des sciences de la santé, université Bretagne Loire-université de Bretagne Occidentale, IBSAM, IBRBS, 22, rue Camille-Desmoulins, 29200 Brest, France; Laboratory of Excellence GR-Ex, institut Imagine, 24, boulevard du Montparnasse, 75015, Paris, France; Laboratoire de génétique moléculaire et histocompatibilité, hôpital Morvan, CHRU de Brest, 2, avenue Foch, 29200 Brest, France.
| | - C Ka
- Inserm UMR1078, faculté de médecine et des sciences de la santé, université Bretagne Loire-université de Bretagne Occidentale, IBSAM, IBRBS, 22, rue Camille-Desmoulins, 29200 Brest, France; Laboratory of Excellence GR-Ex, institut Imagine, 24, boulevard du Montparnasse, 75015, Paris, France; Laboratoire de génétique moléculaire et histocompatibilité, hôpital Morvan, CHRU de Brest, 2, avenue Foch, 29200 Brest, France
| | - J Guellec
- Inserm UMR1078, faculté de médecine et des sciences de la santé, université Bretagne Loire-université de Bretagne Occidentale, IBSAM, IBRBS, 22, rue Camille-Desmoulins, 29200 Brest, France; Laboratory of Excellence GR-Ex, institut Imagine, 24, boulevard du Montparnasse, 75015, Paris, France; Association Gaetan-Saleun, 29, rue Félix-Le-Dantec, 29200 Brest, France
| | - I Gourlaouen
- Inserm UMR1078, faculté de médecine et des sciences de la santé, université Bretagne Loire-université de Bretagne Occidentale, IBSAM, IBRBS, 22, rue Camille-Desmoulins, 29200 Brest, France; Laboratory of Excellence GR-Ex, institut Imagine, 24, boulevard du Montparnasse, 75015, Paris, France; Établissement français du sang, Bretagne, site de Brest, 46 rue Félix-Le-Dantec, 29200 Brest, France
| | - C Férec
- Inserm UMR1078, faculté de médecine et des sciences de la santé, université Bretagne Loire-université de Bretagne Occidentale, IBSAM, IBRBS, 22, rue Camille-Desmoulins, 29200 Brest, France; Laboratoire de génétique moléculaire et histocompatibilité, hôpital Morvan, CHRU de Brest, 2, avenue Foch, 29200 Brest, France; Établissement français du sang, Bretagne, site de Brest, 46 rue Félix-Le-Dantec, 29200 Brest, France
| | - I Callebaut
- Muséum d'histoire naturelle, IRD UMR 206, case 115, IMPMC, Sorbonne universités-UMR CNRS 7590, UPMC université Paris 06, 4, place Jussieu, 75252 Paris cedex 05, France
| | - G Le Gac
- Inserm UMR1078, faculté de médecine et des sciences de la santé, université Bretagne Loire-université de Bretagne Occidentale, IBSAM, IBRBS, 22, rue Camille-Desmoulins, 29200 Brest, France; Laboratory of Excellence GR-Ex, institut Imagine, 24, boulevard du Montparnasse, 75015, Paris, France; Laboratoire de génétique moléculaire et histocompatibilité, hôpital Morvan, CHRU de Brest, 2, avenue Foch, 29200 Brest, France; Établissement français du sang, Bretagne, site de Brest, 46 rue Félix-Le-Dantec, 29200 Brest, France
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30
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Kulkarni SS, Vasantha K, Gogri H, Parchure D, Madkaikar M, Férec C, Fichou Y. First report of Rhnullindividuals in the Indian population and characterization of the underlying molecular mechanisms. Transfusion 2017; 57:1944-1948. [DOI: 10.1111/trf.14150] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/27/2017] [Accepted: 03/31/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Swati S. Kulkarni
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Kasiviswanathan Vasantha
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Harita Gogri
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Disha Parchure
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Manisha Madkaikar
- National Institute of Immunohaematology, Indian Council of Medical Research (NIIH-ICMR); Mumbai India
| | - Claude Férec
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078; Brest France
- Etablissement Français du Sang Bretagne; Brest France
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Centre Hospitalier Régional Universitaire (CHRU), Hôpital Morvan; Brest France
- Faculté de Médecine et des Sciences de la Santé, Université de Bretagne Occidentale (UBO); Brest France
| | - Yann Fichou
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078; Brest France
- Etablissement Français du Sang Bretagne; Brest France
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32
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Tortosa V, di Patti MCB, Musci G, Polticelli F. The human iron exporter ferroportin. Insight into the transport mechanism by molecular modeling. BIO-ALGORITHMS AND MED-SYSTEMS 2016. [DOI: 10.1515/bams-2015-0034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
AbstractFerroportin, a membrane protein belonging to the major facilitator superfamily of transporters, is the only vertebrate iron exporter known so far. Several ferroportin mutations lead to the so-called ferroportin disease or type 4 hemochromatosis, characterized by two distinct iron accumulation phenotypes depending on whether the mutation affects the activity of the protein or its degradation pathway. Through extensive molecular modeling analyses using the structure of all known major facilitator superfamily members as templates, multiple structural models of ferroportin in the three mechanistically relevant conformations (inward open, occluded, and outward open) have been obtained. The best models, selected on the ground of experimental data available on wild-type and mutant ferroportion, provide for the first time a prediction at the atomic level of the dynamics of the transporter. Based on these results, a possible mechanism for iron export is proposed.
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33
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Wallace DF, Subramaniam VN. The global prevalence of HFE and non-HFE hemochromatosis estimated from analysis of next-generation sequencing data. Genet Med 2015; 18:618-26. [PMID: 26633544 DOI: 10.1038/gim.2015.140] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2015] [Accepted: 08/27/2015] [Indexed: 12/31/2022] Open
Abstract
PURPOSE The prevalence of HFE-related hereditary hemochromatosis (HH) among European populations has been well studied. There are no prevalence data for atypical forms of HH caused by mutations in HFE2, HAMP, TFR2, or SLC40A1. The purpose of this study was to estimate the population prevalence of these non-HFE forms of HH. METHODS A list of HH pathogenic variants in publically available next-generation sequence (NGS) databases was compiled and allele frequencies were determined. RESULTS Of 161 variants previously associated with HH, 43 were represented among the NGS data sets; an additional 40 unreported functional variants also were identified. The predicted prevalence of HFE HH and the p.Cys282Tyr mutation closely matched previous estimates from similar populations. Of the non-HFE forms of iron overload, TFR2-, HFE2-, and HAMP-related forms are predicted to be rare, with pathogenic allele frequencies in the range of 0.00007 to 0.0005. Significantly, SLC40A1 variants that have been previously associated with autosomal-dominant ferroportin disease were identified in several populations (pathogenic allele frequency 0.0004), being most prevalent among Africans. CONCLUSION We have, for the first time, estimated the population prevalence of non-HFE HH. This methodology could be applied to estimate the population prevalence of a wide variety of genetic disorders.Genet Med 18 6, 618-626.
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Affiliation(s)
- Daniel F Wallace
- Membrane Transport Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia.,Faculty of Medicine and Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - V Nathan Subramaniam
- Membrane Transport Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, Australia.,Faculty of Medicine and Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
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Abstract
Maintaining physiologic iron concentrations in tissues is critical for metabolism and host defense. Iron absorption in the duodenum, recycling of iron from senescent erythrocytes, and iron mobilization from storage in macrophages and hepatocytes constitute the major iron flows into plasma for distribution to tissues, predominantly for erythropoiesis. All iron transfer to plasma occurs through the iron exporter ferroportin. The concentration of functional membrane-associated ferroportin is controlled by its ligand, the iron-regulatory hormone hepcidin, and fine-tuned by regulatory mechanisms serving iron homeostasis, oxygen utilization, host defense, and erythropoiesis. Fundamental questions about the structure and biology of ferroportin remain to be answered.
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35
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Taniguchi R, Kato HE, Font J, Deshpande CN, Wada M, Ito K, Ishitani R, Jormakka M, Nureki O. Outward- and inward-facing structures of a putative bacterial transition-metal transporter with homology to ferroportin. Nat Commun 2015; 6:8545. [PMID: 26461048 PMCID: PMC4633820 DOI: 10.1038/ncomms9545] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 09/03/2015] [Indexed: 12/21/2022] Open
Abstract
In vertebrates, the iron exporter ferroportin releases Fe2+ from cells into plasma, thereby maintaining iron homeostasis. The transport activity of ferroportin is suppressed by the peptide hormone hepcidin, which exhibits upregulated expression in chronic inflammation, causing iron-restrictive anaemia. However, due to the lack of structural information about ferroportin, the mechanisms of its iron transport and hepcidin-mediated regulation remain largely elusive. Here we report the crystal structures of a putative bacterial homologue of ferroportin, BbFPN, in both the outward- and inward-facing states. Despite undetectable sequence similarity, BbFPN adopts the major facilitator superfamily fold. A comparison of the two structures reveals that BbFPN undergoes an intra-domain conformational rearrangement during the transport cycle. We identify a substrate metal-binding site, based on structural and mutational analyses. Furthermore, the BbFPN structures suggest that a predicted hepcidin-binding site of ferroportin is located within its central cavity. Thus, BbFPN may be a valuable structural model for iron homeostasis regulation by ferroportin. Iron export from vertebrate cells is mediated by ferroportin, which is suppressed by the peptide hormone hepcidin. Taniguchi et al. present crystal structures of a putative bacterial ferroportin homologue in both outward- and inward-facing states, providing insight into its transport mechanism.
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Affiliation(s)
- Reiya Taniguchi
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.,Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Hideaki E Kato
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.,Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Josep Font
- Structural Biology Program, Centenary Institute, Locked Bag 6, Sydney, New South Wales 2042, Australia.,Faculty of Medicine, Central Clinical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Chandrika N Deshpande
- Structural Biology Program, Centenary Institute, Locked Bag 6, Sydney, New South Wales 2042, Australia.,Faculty of Medicine, Central Clinical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Miki Wada
- Technical office, The Institute of Medical Science, The University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Koichi Ito
- Department of Medical Genome Sciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa-shi, Chiba 277-8562, Japan
| | - Ryuichiro Ishitani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.,Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
| | - Mika Jormakka
- Structural Biology Program, Centenary Institute, Locked Bag 6, Sydney, New South Wales 2042, Australia.,Faculty of Medicine, Central Clinical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Osamu Nureki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan.,Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako-shi, Saitama 351-0198, Japan
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36
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Vargas JA, Muñoz A, Samper B, Bornstein B. [Usefulness of a diagnostic algorithm hyperferritinemia: A case report of a Spanish family with hereditary hemochromatosis and mutation in SLC40A1 gene]. Med Clin (Barc) 2015; 145:42-3. [PMID: 25441019 DOI: 10.1016/j.medcli.2014.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 07/28/2014] [Accepted: 09/04/2014] [Indexed: 11/25/2022]
Affiliation(s)
- Juan Antonio Vargas
- Servicio de Medicina Interna, Hospital Universitario Puerta de Hierro, Majadahonda, Madrid, España; Instituto de Investigación Biomédica Puerta de Hierro (IDIPHIM), Majadahonda, Madrid, España
| | - Alejandro Muñoz
- Servicio de Medicina Interna, Hospital Universitario Puerta de Hierro, Majadahonda, Madrid, España
| | - Begoña Samper
- Servicio de Bioquímica, Hospital Universitario Puerta de Hierro, Majadahonda, Madrid, España
| | - Belén Bornstein
- Instituto de Investigación Biomédica Puerta de Hierro (IDIPHIM), Majadahonda, Madrid, España; Servicio de Bioquímica, Hospital Universitario Puerta de Hierro, Majadahonda, Madrid, España; Centro de Investigación Biomédica en Red en Enfermedades Raras (CIBERER), Madrid, España.
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37
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Chen SR, Yang LQ, Chong YT, Jie YS, Wu YK, Yang J, Lin GL, Li XH. Novel gain of function mutation in the SLC40A1 gene associated with hereditary haemochromatosis type 4. Intern Med J 2015; 45:672-6. [PMID: 26059880 DOI: 10.1111/imj.12764] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 02/28/2015] [Indexed: 02/05/2023]
Abstract
Here we report the case of a 69-year-old Chinese Han woman who presented with liver cirrhosis, diabetes mellitus, skin hyperpigmentation, hyperferritinaemia and high transferrin saturation. Subsequent genetic analyses identified a novel heterozygous mutation (p.Cys326Phe) in the SLC40A1 gene. This is the first report regarding a SLC40A1 mutation in the Chinese Han population and provides novel clinical evidence for the importance of p.Cys326 in SLC40A1 gene function.
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Affiliation(s)
- S-R Chen
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun-Yat-Sen University, GuangZhou, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, GuangZhou, China
| | - L-Q Yang
- Department of Infectious Diseases, The First People's Hospital of YueYang, YueYang, China
| | - Y-T Chong
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun-Yat-Sen University, GuangZhou, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, GuangZhou, China
| | - Y-S Jie
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun-Yat-Sen University, GuangZhou, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, GuangZhou, China
| | - Y-K Wu
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun-Yat-Sen University, GuangZhou, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, GuangZhou, China
| | - J Yang
- Department of Infectious Diseases, The First People's Hospital of YueYang, YueYang, China
| | - G-L Lin
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun-Yat-Sen University, GuangZhou, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, GuangZhou, China
| | - X-H Li
- Department of Infectious Diseases, The Third Affiliated Hospital of Sun-Yat-Sen University, GuangZhou, China
- Key Laboratory of Tropical Disease Control (Sun Yat-Sen University), Ministry of Education, GuangZhou, China
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Fichou Y, Gehannin P, Corre M, Le Guern A, Le Maréchal C, Le Gac G, Férec C. Extensive functional analyses ofRHDsplice site variants: Insights into the potential role of splicing in the physiology of Rh. Transfusion 2015; 55:1432-43. [DOI: 10.1111/trf.13083] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Revised: 01/08/2015] [Accepted: 02/10/2015] [Indexed: 12/18/2022]
Affiliation(s)
- Yann Fichou
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078
- Etablissement Français du Sang (EFS)-Région Bretagne
| | - Pierre Gehannin
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078
- Etablissement Français du Sang (EFS)-Région Bretagne
| | - Manon Corre
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078
- Etablissement Français du Sang (EFS)-Région Bretagne
| | - Alice Le Guern
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078
- Etablissement Français du Sang (EFS)-Région Bretagne
| | - Cédric Le Maréchal
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078
- Etablissement Français du Sang (EFS)-Région Bretagne
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Centre Hospitalier Régional Universitaire (CHRU), Hôpital Morvan
- Faculté de Médecine et des Sciences de la Santé, Université de Bretagne Occidentale; Brest France
| | - Gérald Le Gac
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078
- Etablissement Français du Sang (EFS)-Région Bretagne
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Centre Hospitalier Régional Universitaire (CHRU), Hôpital Morvan
- Faculté de Médecine et des Sciences de la Santé, Université de Bretagne Occidentale; Brest France
| | - Claude Férec
- Institut National de la Santé et de la Recherche Médicale (Inserm), UMR1078
- Etablissement Français du Sang (EFS)-Région Bretagne
- Laboratoire de Génétique Moléculaire et d'Histocompatibilité, Centre Hospitalier Régional Universitaire (CHRU), Hôpital Morvan
- Faculté de Médecine et des Sciences de la Santé, Université de Bretagne Occidentale; Brest France
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39
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Impact of D181V and A69T on the function of ferroportin as an iron export pump and hepcidin receptor. Biochim Biophys Acta Mol Basis Dis 2014; 1842:1406-12. [DOI: 10.1016/j.bbadis.2014.05.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Revised: 05/06/2014] [Accepted: 05/14/2014] [Indexed: 01/03/2023]
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