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Dickey AK, Naik H, Keel SB, Levy C, Beaven SW, Elmariah SB, Erwin AL, Goddu RJ, Hedstrom K, Leaf RK, Kazamel M, Mazepa M, Philpotts LL, Quigley J, Raef H, Rudnick SR, Saberi B, Thapar M, Ungar J, Wang B, Balwani M. Evidence-based consensus guidelines for the diagnosis and management of erythropoietic protoporphyria and X-linked protoporphyria. J Am Acad Dermatol 2023; 89:1227-1237. [PMID: 36041558 PMCID: PMC9968824 DOI: 10.1016/j.jaad.2022.08.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 07/07/2022] [Accepted: 08/15/2022] [Indexed: 11/16/2022]
Abstract
Erythropoietic protoporphyria and X-linked protoporphyria are rare genetic photodermatoses. Limited expertise with these disorders among physicians leads to diagnostic delays. Here, we present evidence-based consensus guidelines for the diagnosis, monitoring, and management of erythropoietic protoporphyria and X-linked protoporphyria. A systematic literature review was conducted, and reviewed among subcommittees of experts, divided by topic. Consensus on guidelines was reached within each subcommittee and then among all members of the committee. The appropriate biochemical and genetic testing to establish the diagnosis is reviewed in addition to the interpretation of results. Prevention of symptoms, management of acute phototoxicity, and pharmacologic and nonpharmacologic treatment options are discussed. The importance of ongoing monitoring for liver disease, iron deficiency, and vitamin D deficiency is discussed with management guidance. Finally, management of pregnancy and surgery and the safety of other therapies are summarized. We emphasize that these are multisystemic disorders that require longitudinal monitoring. These guidelines provide a structure for evidence-based diagnosis and management for practicing physicians. Early diagnosis and management of these disorders are essential, particularly given the availability of new and emerging therapies.
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Affiliation(s)
- Amy K Dickey
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts; Harvard Medical School, Boston, Massachusetts
| | - Hetanshi Naik
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Siobán B Keel
- Division of Hematology, University of Washington School of Medicine, Seattle, Washington
| | - Cynthia Levy
- Division of Digestive Health and Liver Diseases, University of Miami Miller School of Medicine, Miami, Florida
| | - Simon W Beaven
- Vatche & Tamar Manoukian Division of Digestive Diseases, David Geffen School of Medicine, University of California Los Angeles Medical Center, Los Angeles, California
| | - Sarina B Elmariah
- Harvard Medical School, Boston, Massachusetts; Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts
| | - Angelika L Erwin
- Center for Personalized Genetic Healthcare, Cleveland Clinic, Cleveland, Ohio
| | - Robert J Goddu
- Division of Continuing Education, University of Colorado Boulder, Boulder, Colorado
| | - Karli Hedstrom
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Rebecca K Leaf
- Harvard Medical School, Boston, Massachusetts; Division of Hematology and Oncology, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts
| | - Mohamed Kazamel
- Department of Neurology, University of Alabama at Birmingham, Birmingham, Alabama
| | - Marshall Mazepa
- Division of Hematology and Oncology, University of Minnesota Medical Center, Minneapolis, Minnesota
| | | | - John Quigley
- Division of Hematology/Oncology, Department of Medicine, University of Illinois Chicago, Chicago, Illinois
| | - Haya Raef
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Massachusetts General Hospital, Boston, Massachusetts; Department of Dermatology, Massachusetts General Hospital, Boston, Massachusetts
| | - Sean R Rudnick
- Department of Internal Medicine, Section on Gastroenterology and Hepatology, Atrium Health Wake Forest Baptist, Winston-Salem, North Carolina
| | - Behnam Saberi
- Harvard Medical School, Boston, Massachusetts; Division of Gastroenterology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Manish Thapar
- Division of Gastroenterology, Thomas Jefferson University Hospital, Philadelphia, Pennsylvania
| | - Jonathan Ungar
- Department of Dermatology, Mount Sinai Hospital, New York, New York
| | - Bruce Wang
- Department of Medicine, University of California San Francisco Medical Center, San Francisco, California
| | - Manisha Balwani
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, New York.
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Xue W, Jian W, Meng Y, Wang T, Cai L, Yu Y, Yu Y, Xia Z, Zhang C. Knockdown of SETD2 promotes erastin-induced ferroptosis in ccRCC. Cell Death Dis 2023; 14:539. [PMID: 37604811 PMCID: PMC10442429 DOI: 10.1038/s41419-023-06057-8] [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: 12/23/2022] [Revised: 06/15/2023] [Accepted: 08/10/2023] [Indexed: 08/23/2023]
Abstract
Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancer and is associated with poor prognosis. The histone H3 lysine 36 methyltransferase SET-domain-containing 2 (SETD2) has been reported to be expressed at low levels and frequently mutated in ccRCC. Ferroptosis, a form of death distinct from apoptosis and necrosis, has been reported in recent years in renal cancer. However, the relationship between SETD2 and ferroptosis in renal cancer is not clear. Here, we demonstrated that SETD2 was expressed at low levels in ccRCC and was associated with poor prognosis. Moreover, we found that knockdown of SETD2 increased lipid peroxidation and Fe2+ levels in tumor cells, thereby increasing the sensitivity of erastin, a ferroptosis inducer. Mechanistically, histone H3 lysine 36 trimethylation (H3K36me3) which was catalyzed by SETD2, interacted with the promoter of ferrochelatase (FECH) to regulate its transcription and ferroptosis-related signaling pathways. In conclusion, the presesnt study revealed that knockdown of the epigenetic molecule, SETD2, significantly increases the sensitivity of ferroptosis inducers which promotes tumor cell death, thereby indicating that SETD2 may be a potential therapeutic target for ccRCC.
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Affiliation(s)
- Wei Xue
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Wengang Jian
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Yuyang Meng
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Tengda Wang
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Licheng Cai
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Yongchun Yu
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Yipeng Yu
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Zhinan Xia
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China
| | - Cheng Zhang
- Department of Urology, the First Affiliated Hospital of Harbin Medical University, Harbin, 150001, Heilongjiang, China.
- Department of Urology, the Fourth Affiliated Hospital of Zhejiang University School of Medicine, Yiwu, 322000, Zhejiang, China.
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3
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Iron Metabolism in the Disorders of Heme Biosynthesis. Metabolites 2022; 12:metabo12090819. [PMID: 36144223 PMCID: PMC9505951 DOI: 10.3390/metabo12090819] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 01/19/2023] Open
Abstract
Given its remarkable property to easily switch between different oxidative states, iron is essential in countless cellular functions which involve redox reactions. At the same time, uncontrolled interactions between iron and its surrounding milieu may be damaging to cells and tissues. Heme—the iron-chelated form of protoporphyrin IX—is a macrocyclic tetrapyrrole and a coordination complex for diatomic gases, accurately engineered by evolution to exploit the catalytic, oxygen-binding, and oxidoreductive properties of iron while minimizing its damaging effects on tissues. The majority of the body production of heme is ultimately incorporated into hemoglobin within mature erythrocytes; thus, regulation of heme biosynthesis by iron is central in erythropoiesis. Additionally, heme is a cofactor in several metabolic pathways, which can be modulated by iron-dependent signals as well. Impairment in some steps of the pathway of heme biosynthesis is the main pathogenetic mechanism of two groups of diseases collectively known as porphyrias and congenital sideroblastic anemias. In porphyrias, according to the specific enzyme involved, heme precursors accumulate up to the enzyme stop in disease-specific patterns and organs. Therefore, different porphyrias manifest themselves under strikingly different clinical pictures. In congenital sideroblastic anemias, instead, an altered utilization of mitochondrial iron by erythroid precursors leads to mitochondrial iron overload and an accumulation of ring sideroblasts in the bone marrow. In line with the complexity of the processes involved, the role of iron in these conditions is then multifarious. This review aims to summarise the most important lines of evidence concerning the interplay between iron and heme metabolism, as well as the clinical and experimental aspects of the role of iron in inherited conditions of altered heme biosynthesis.
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Graziadei G, Duca L, Granata F, De Luca G, De Giovanni A, Brancaleoni V, Nava I, Di Pierro E. Microcytosis in Erythropoietic Protoporphyria. Front Physiol 2022; 13:841050. [PMID: 35309058 PMCID: PMC8928159 DOI: 10.3389/fphys.2022.841050] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/04/2022] [Indexed: 01/01/2023] Open
Abstract
Partial deficiency of the last enzyme of the heme biosynthetic pathway, namely, ferrochelatase (FECH), is responsible for erythropoietic protoporphyria (EPP) in humans. This disorder is characterized by painful skin photosensitivity, due to excessive protoporphyrin IX (PPIX) production in erythrocytes. Although several papers report the presence of iron deficiency anemia in about 50% of EPP patients, there is still no a conclusive explanation of the why this occurs. In the present work, we explored hematological indices and iron status in 20 unrelated Italian EPP patients in order to propose a new hypothesis. Our data show that microcytosis is present in EPP patients also in the absence of anemia and iron deficiency with a link between PPIX accumulation and reduced MCV, probably indicating an indirect condition of heme deficiency. Patients studied had a downward shift of iron parameters due to increased hepcidin concentrations only in a state of repleted iron stores. Interestingly, hemoglobin synthesis was not limited by iron supply except in cases with further iron loss, in which concomitantly increased soluble transferrin (Tf) receptor (sTfR) levels were detected. The mechanisms involved in the iron uptake downregulation in EPP remain unclear, and the role of PPIX accumulation in microcytosis.
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Affiliation(s)
- Giovanna Graziadei
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Lorena Duca
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Francesca Granata
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | | | - Anna De Giovanni
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Valentina Brancaleoni
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Isabella Nava
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
| | - Elena Di Pierro
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, Milan, Italy
- *Correspondence: Elena Di Pierro, ;
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5
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Iron in Porphyrias: Friend or Foe? Diagnostics (Basel) 2022; 12:diagnostics12020272. [PMID: 35204362 PMCID: PMC8870839 DOI: 10.3390/diagnostics12020272] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/10/2022] [Accepted: 01/13/2022] [Indexed: 02/04/2023] Open
Abstract
Iron is a trace element that is important for many vital processes, including oxygen transport, oxidative metabolism, cellular proliferation, and catalytic reactions. Iron supports these functions mainly as part of the heme molecule. Heme synthesis is an eight-step process which, when defective at the level of one of the eight enzymes involved, can cause the development of a group of diseases, either inherited or acquired, called porphyrias. Despite the strict link between iron and heme, the role of iron in the different types of porphyrias, particularly as a risk factor for disease development/progression or as a potential therapeutic target or molecule, is still being debated, since contrasting results have emerged from clinical observations, in vitro studies and animal models. In this review we aim to deepen such aspects by drawing attention to the current evidence on the role of iron in porphyrias and its potential implication. Testing for iron status and its metabolic pathways through blood tests, imaging techniques or genetic studies on patients affected by porphyrias can provide additional diagnostic and prognostic value to the clinical care, leading to a more tailored and effective management.
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Di Pierro E, Granata F, De Canio M, Rossi M, Ricci A, Marcacci M, De Luca G, Sarno L, Barbieri L, Ventura P, Graziadei G. Recognized and Emerging Features of Erythropoietic and X-Linked Protoporphyria. Diagnostics (Basel) 2022; 12:diagnostics12010151. [PMID: 35054318 PMCID: PMC8775248 DOI: 10.3390/diagnostics12010151] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/31/2021] [Accepted: 01/06/2022] [Indexed: 02/06/2023] Open
Abstract
Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are inherited disorders resulting from defects in two different enzymes of the heme biosynthetic pathway, i.e., ferrochelatase (FECH) and delta-aminolevulinic acid synthase-2 (ALAS2), respectively. The ubiquitous FECH catalyzes the insertion of iron into the protoporphyrin ring to generate the final product, heme. After hemoglobinization, FECH can utilize other metals like zinc to bind the remainder of the protoporphyrin molecules, leading to the formation of zinc protoporphyrin. Therefore, FECH deficiency in EPP limits the formation of both heme and zinc protoporphyrin molecules. The erythroid-specific ALAS2 catalyses the synthesis of delta-aminolevulinic acid (ALA), from the union of glycine and succinyl-coenzyme A, in the first step of the pathway in the erythron. In XLP, ALAS2 activity increases, resulting in the amplified formation of ALA, and iron becomes the rate-limiting factor for heme synthesis in the erythroid tissue. Both EPP and XLP lead to the systemic accumulation of protoporphyrin IX (PPIX) in blood, erythrocytes, and tissues causing the major symptom of cutaneous photosensitivity and several other less recognized signs that need to be considered. Although significant advances have been made in our understanding of EPP and XLP in recent years, a complete understanding of the factors governing the variability in clinical expression and the severity (progression) of the disease remains elusive. The present review provides an overview of both well-established facts and the latest findings regarding these rare diseases.
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Affiliation(s)
- Elena Di Pierro
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (F.G.); (G.D.L.); (G.G.)
- Correspondence: or ; Tel.: +39-0255036155
| | - Francesca Granata
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (F.G.); (G.D.L.); (G.G.)
| | - Michele De Canio
- Porphyria and Rare Diseases Centre, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (M.D.C.); (L.B.)
| | - Mariateresa Rossi
- Department of Dermatology, ASST Spedali Civili di Brescia, University of Brescia, 25123 Brescia, Italy; (M.R.); (L.S.)
| | - Andrea Ricci
- Internal Medicine Unit, Department of Medical and Surgical Science for Children and Adults, University of Modena e Reggio Emilia, 41124 Modena, Italy; (A.R.); (M.M.); (P.V.)
| | - Matteo Marcacci
- Internal Medicine Unit, Department of Medical and Surgical Science for Children and Adults, University of Modena e Reggio Emilia, 41124 Modena, Italy; (A.R.); (M.M.); (P.V.)
| | - Giacomo De Luca
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (F.G.); (G.D.L.); (G.G.)
| | - Luisa Sarno
- Department of Dermatology, ASST Spedali Civili di Brescia, University of Brescia, 25123 Brescia, Italy; (M.R.); (L.S.)
| | - Luca Barbieri
- Porphyria and Rare Diseases Centre, San Gallicano Dermatological Institute IRCCS, 00144 Rome, Italy; (M.D.C.); (L.B.)
| | - Paolo Ventura
- Internal Medicine Unit, Department of Medical and Surgical Science for Children and Adults, University of Modena e Reggio Emilia, 41124 Modena, Italy; (A.R.); (M.M.); (P.V.)
| | - Giovanna Graziadei
- Dipartimento di Medicina Interna, Fondazione IRCCS Cà Granda Ospedale Maggiore Policlinico, 20122 Milan, Italy; (F.G.); (G.D.L.); (G.G.)
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7
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Saha P, Xiao X, Li Y, Golonka RM, Abokor AA, Yeoh BS, Vijay-Kumar M. Distinct iron homeostasis in C57BL/6 and Balb/c mouse strains. Physiol Rep 2021; 8:e14441. [PMID: 32385968 PMCID: PMC7210116 DOI: 10.14814/phy2.14441] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2020] [Revised: 04/18/2020] [Accepted: 04/20/2020] [Indexed: 12/17/2022] Open
Abstract
C57BL/6 (BL6) and Balb/c mice exhibit prototypical Th1- and Th2-dominant immune predispositions, respectively. Iron is a proinflammatory metal ion; however, limited information is documented on the differences in iron homeostasis between BL6 and Balb/c strains. The objective of this study was to investigate the extent to which strain-level differences in these mice dictates the regulation of iron homeostasis during physiologic and inflammatory conditions. At basal levels, Balb/c mice displayed significantly higher levels of iron in systemic circulation and tissue compared to BL6 mice. Moreover, Balb/c mice had greater iron absorption as indicated by higher gene expressions of duodenal DcytB, DMT1, Fpn, SFT, and Heph. Similarly, hepatic Tf, TfR1, TfR2, and DMT1 expressions were augmented in Balb/c mice. Interestingly, there was no change in hepatic Hamp expression between the two strains, suggesting that the disparity in their maintenance of iron is independent of hepcidin. Additionally, the basal levels of intracellular labile iron pool in Balb/c intestinal epithelial cells, and bone marrow-derived macrophages and neutrophils, were higher compared to BL6 mice. When mice were challenged with lipopolysaccharide, the acute inflammatory response in BL6 mice was more pronounced than in Balb/c mice, as indicated by the more rapid development of hypoferremia and upregulation of serum IL-6 and TNF-α levels in BL6 mice. In conclusion, this study underscores that iron homeostasis is distinct between BL6 and Balb/c strains under both physiologic and inflammatory conditions.
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Affiliation(s)
- Piu Saha
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Xia Xiao
- Center for Systems Biology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Yaqi Li
- Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA, USA
| | - Rachel M Golonka
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Ahmed A Abokor
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Beng San Yeoh
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
| | - Matam Vijay-Kumar
- Department of Physiology & Pharmacology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA.,Department of Medical Microbiology & Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, USA
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8
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Schmidt PJ, Hollowell ML, Fitzgerald K, Butler JS, Fleming MD. Mild iron deficiency does not ameliorate the phenotype of a murine erythropoietic protoporphyria model. Am J Hematol 2020; 95:492-496. [PMID: 31990410 DOI: 10.1002/ajh.25743] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 01/19/2020] [Accepted: 01/23/2020] [Indexed: 11/11/2022]
Abstract
Reduced ferrochelatase activity in erythropoietic protoporphyria (EPP) causes the accumulation of protoporphyrin IX (PPIX) leading to acute cutaneous photosensitivity and liver injury. Many EPP patients also have a mild hypochromic, microcytic anemia and iron deficiency. Iron deficiency can lead to decreased PPIX accumulation in another erythropoietic porphyria, congenital erythropoietic porphyria (CEP). Expression of the iron regulatory peptide hepcidin is negatively regulated by the serine protease TMPRSS6. Hepcidin induction by siRNA-mediated inhibition of TMPRSS6 expression reduces iron availability and induces iron deficiency. To interrogate the therapeutic potential of iron deficiency to modify EPP, we treated an ethylnitrosourea-induced mouse model of EPP, Fech m1Pas , with a GalNAc-conjugated Tmprss6 siRNA and PPIX levels, anemia and iron parameters were monitored. The GalNAc-RNAi therapeutic reduces Tmprss6 expression and induces mild iron deficiency in Fech m1Pas animals. However, decreases in erythrocyte PPIX levels and liver PPIX accumulation were not seen. These results indicate short-term induction of iron deficiency, at least in a murine model of EPP, does not lead to decreased PPIX production.
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Affiliation(s)
- Paul J. Schmidt
- Department of PathologyBoston Children's Hospital and Harvard Medical School Boston Massachusetts
| | - Monica L. Hollowell
- Department of PathologyBoston Children's Hospital and Harvard Medical School Boston Massachusetts
| | | | | | - Mark D. Fleming
- Department of PathologyBoston Children's Hospital and Harvard Medical School Boston Massachusetts
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9
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Lefebvre T, Millot S, Richard E, Blouin JM, Lalanne M, Lamrissi-Garcia I, Costet P, Lyoumi S, Gouya L, Puy H, Moreau-Gaudry F, de Verneuil H, Karim Z, Ged C. Genetic background influences hepcidin response to iron imbalance in a mouse model of hemolytic anemia (Congenital erythropoietic porphyria). Biochem Biophys Res Commun 2019; 520:297-303. [DOI: 10.1016/j.bbrc.2019.09.141] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2019] [Revised: 09/30/2019] [Accepted: 09/30/2019] [Indexed: 01/10/2023]
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10
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Balwani M. Erythropoietic Protoporphyria and X-Linked Protoporphyria: pathophysiology, genetics, clinical manifestations, and management. Mol Genet Metab 2019; 128:298-303. [PMID: 30704898 PMCID: PMC6656624 DOI: 10.1016/j.ymgme.2019.01.020] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/23/2019] [Accepted: 01/23/2019] [Indexed: 11/18/2022]
Abstract
Erythropoietic Protoporphyria (EPP) and X-linked Protoporphyria (XLP) are rare, genetic photodermatoses resulting from defects in enzymes of the heme-biosynthetic pathway. EPP results from the partial deficiency of ferrochelatase, and XLP results from gain-of-function mutations in erythroid specific ALAS2. Both disorders result in the accumulation of erythrocyte protoporphyrin, which is released in the plasma and taken up by the liver and vascular endothelium. The accumulated protoporphyrin is activated by sunlight exposure, generating singlet oxygen radical reactions leading to tissue damage and excruciating pain. About 2-5% of patients develop clinically significant liver dysfunction due to protoporphyrin deposition in bile and/or hepatocytes which can advance to cholestatic liver failure requiring transplantation. Clinically these patients present with acute, severe, non-blistering phototoxicity within minutes of sun-exposure. Anemia is seen in about 47% of patients and about 27% of patients will develop abnormal serum aminotransferases. The diagnosis of EPP and XLP is made by detection of markedly increased erythrocyte protoporphyrin levels with a predominance of metal-free protoporphyrin. Genetic testing by sequencing the FECH or ALAS2 gene confirms the diagnosis. Treatment is limited to sun-protection and there are no currently available FDA-approved therapies for these disorders. Afamelanotide, a synthetic analogue of α-melanocyte stimulating hormone was found to increase pain-free sun exposure and improve quality of life in adults with EPP. It has been approved for use in the European Union since 2014 and is not available in the U.S. In addition to the development of effective therapeutics, future studies are needed to establish the role of iron and the risks related to the development of hepatopathy in these patients.
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MESH Headings
- 5-Aminolevulinate Synthetase/genetics
- Anemia/etiology
- Clinical Trials as Topic
- Dermatitis, Phototoxic
- Disease Management
- Genes, X-Linked
- Heme/metabolism
- Humans
- Liver Diseases/etiology
- Liver Diseases/physiopathology
- Porphyrias, Hepatic/complications
- Porphyrias, Hepatic/genetics
- Porphyrias, Hepatic/physiopathology
- Porphyrias, Hepatic/therapy
- Protoporphyria, Erythropoietic/complications
- Protoporphyria, Erythropoietic/genetics
- Protoporphyria, Erythropoietic/physiopathology
- Protoporphyria, Erythropoietic/therapy
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Affiliation(s)
- Manisha Balwani
- Department of Genetics and Genomic Sciences and Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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Phillips J, Farrell C, Wang Y, Singal AK, Anderson K, Balwani M, Bissell M, Bonkovsky H, Seay T, Paw B, Desnick R, Bloomer J. Strong correlation of ferrochelatase enzymatic activity with Mitoferrin-1 mRNA in lymphoblasts of patients with protoporphyria. Mol Genet Metab 2019; 128:391-395. [PMID: 30391163 PMCID: PMC7328821 DOI: 10.1016/j.ymgme.2018.10.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 10/20/2018] [Accepted: 10/21/2018] [Indexed: 11/25/2022]
Abstract
Accumulation of protoporphyrin IX (PPIX) and Zn-PPIX, are the clinical hallmarks of protoporphyria. Phenotypic expression of protoporphyria is due to decreased activity of ferrochelatase (FECH) or to increased activity of aminolevulinic acid synthase (ALAS) in red blood cells. Other genetic defects have been shown to contribute to disease severity including loss of function mutations in the mitochondrial AAA-ATPase, CLPX and mutations in the Iron-responsive element binding protein 2 (IRP2), in mice. It is clear that multiple paths lead to a common phenotype of excess plasma PPIX that causes a phototoxic reaction on sun exposed areas. In this study we examined the association between mitochondrial iron acquisition and utilization with activity of FECH. Our data show that there is a metabolic link between the activity FECH and levels of MFRN1 mRNA. We examined the correlation between FECH activity and MFRN1 mRNA in cell lines established from patients with the classical protoporphyria, porphyria due to defects in ALAS2 mutations. Our data confirm MFRN1 message levels positively correlated with FECH enzymatic activity in all cell types.
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Affiliation(s)
- John Phillips
- Department of Medicine, Division of Hematology, University of Utah School of Medicine, Salt Lake City, UT, United States.
| | - Collin Farrell
- Department of Medicine, Division of Hematology, University of Utah School of Medicine, Salt Lake City, UT, United States
| | - Yongming Wang
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Ashwani K Singal
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Karl Anderson
- Department of Medicine, Division of Gastroenterology, University of Texas Medical Branch, Galveston, TX, United States
| | - Manisha Balwani
- Department of Genetics, Icahn school of Medicine, New York, NY, United States
| | - Montgomery Bissell
- Department of Medicine, Division of Gastroenterology, University of California in San Francisco, San Francisco, CA, United States
| | - Herbert Bonkovsky
- Department of Medicine, Division of Gastroenterology, Wake Forest University, United States
| | - Toni Seay
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL, United States
| | - Barry Paw
- Department of Medicine, Hematology, Brigham and Women's Hospital, Boston, MA, United States
| | - Robert Desnick
- Department of Genetics, Icahn school of Medicine, New York, NY, United States
| | - Joseph Bloomer
- Department of Medicine, Division of Gastroenterology and Hepatology, University of Alabama at Birmingham, Birmingham, AL, United States
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12
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Yasuda M, Desnick RJ. Murine models of the human porphyrias: Contributions toward understanding disease pathogenesis and the development of new therapies. Mol Genet Metab 2019; 128:332-341. [PMID: 30737139 PMCID: PMC6639143 DOI: 10.1016/j.ymgme.2019.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 02/07/2023]
Abstract
Mouse models of the human porphyrias have proven useful for investigations of disease pathogenesis and to facilitate the development of new therapeutic approaches. To date, mouse models have been generated for all major porphyrias, with the exception of X-linked protoporphyria (XLP) and the ultra rare 5-aminolevulinic acid dehydratase deficient porphyria (ADP). Mouse models have been generated for the three autosomal dominant acute hepatic porphyrias, acute intermittent porphyria (AIP), hereditary coproporphyria (HCP), and variegate porphyria (VP). The AIP mice, in particular, provide a useful investigative model as they have been shown to have acute biochemical attacks when induced with the prototypic porphyrinogenic drug, phenobarbital. In addition to providing important insights into the disease pathogenesis of the neurological impairment in AIP, these mice have been valuable for preclinical evaluation of liver-targeted gene therapy and RNAi-mediated approaches. Mice with severe HMBS deficiency, which clinically and biochemically mimic the early-onset homozygous dominant AIP (HD-AIP) patients, have been generated and were used to elucidate the striking phenotypic differences between AIP and HD-AIP. Mice modeling the hepatocutaneous porphyria, porphyria cutanea tarda (PCT), made possible the identification of the iron-dependent inhibitory mechanism of uroporphyrinogen decarboxylase (UROD) that leads to symptomatic PCT. Mouse models for the two autosomal recessive erythropoietic porphyrias, congenital erythropoietic porphyria (CEP) and erythropoeitic protoporphyria (EPP), recapitulate many of the clinical and biochemical features of the severe human diseases and have been particularly useful for evaluation of bone marrow transplantation and hematopoietic stem cell (HSC)-based gene therapy approaches. The EPP mice have also provided valuable insights into the underlying pathogenesis of EPP-induced liver damage and anemia.
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Affiliation(s)
- Makiko Yasuda
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
| | - Robert J Desnick
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA.
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13
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Yang X, Zhang H, Shang J, Liu G, Xia T, Zhao C, Sun G, Dou H. Comparative analysis of the blood transcriptomes between wolves and dogs. Anim Genet 2018; 49:291-302. [PMID: 29953636 DOI: 10.1111/age.12675] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/27/2018] [Indexed: 12/24/2022]
Abstract
Dogs were domesticated by human and originated from wolves. Their evolutionary relationships have attracted much scientific interest due to their genetic affinity but different habitats. To identify the differences between dogs and wolves associated with domestication, we analysed the blood transcriptomes of wolves and dogs by RNA-Seq. We obtained a total of 30.87 Gb of raw reads from two dogs and three wolves using RNA-Seq technology. Comparisons of the wolf and dog transcriptomes revealed 524 genes differentially expressed genes between them. We found that some genes related to immune function (DCK, ICAM4, GAPDH and BSG) and aerobic capacity (HBA1, HBA2 and HBB) were more highly expressed in the wolf. Six differentially expressed genes related to the innate immune response (CCL23, TRIM10, DUSP10, RAB27A, CLEC5A and GCH1) were found in the wolf by a Gene Ontology enrichment analysis. Immune system development was also enriched only in the wolf group. The ALAS2, HMBS and FECH genes, shown to be enriched by the Kyoto Encyclopedia of Genes and Genomes analysis, were associated with the higher aerobic capacity and hypoxia endurance of the wolf. The results suggest that the wolf might have greater resistance to pathogens, hypoxia endurance and aerobic capacity than dogs do.
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Affiliation(s)
- X Yang
- College of Life Science, Qufu Normal University, Jingxuan West Road No. 57, Qufu, Shandong, 273165, China
| | - H Zhang
- College of Life Science, Qufu Normal University, Jingxuan West Road No. 57, Qufu, Shandong, 273165, China
| | - J Shang
- College of Information Science and Engineering, Qufu Normal University, Yantai North Road No. 80, Rizhao, Shandong, 276826, China
| | - G Liu
- College of Life Science, Qufu Normal University, Jingxuan West Road No. 57, Qufu, Shandong, 273165, China
| | - T Xia
- College of Life Science, Qufu Normal University, Jingxuan West Road No. 57, Qufu, Shandong, 273165, China
| | - C Zhao
- College of Life Science, Qufu Normal University, Jingxuan West Road No. 57, Qufu, Shandong, 273165, China
| | - G Sun
- College of Life Science, Qufu Normal University, Jingxuan West Road No. 57, Qufu, Shandong, 273165, China
| | - H Dou
- Dailake National Nature Reserve, Manzhouli Road No. 16, Hulunbuir, Inner Mongolia, 021000, China
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14
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Boswell-Casteel RC, Fukuda Y, Schuetz JD. ABCB6, an ABC Transporter Impacting Drug Response and Disease. AAPS JOURNAL 2017; 20:8. [PMID: 29192381 DOI: 10.1208/s12248-017-0165-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 10/16/2017] [Indexed: 12/11/2022]
Abstract
Recent findings have discovered how insufficiency of ATP-binding cassette (ABC) transporter, ABCB6, can negatively impact human health. These advances were made possible by, first, finding that ABCB6 deficiency was the genetic basis for some severe transfusion reactions and by, second, determining that functionally impaired ABCB6 variants enhanced the severity of porphyria, i.e., diseases associated with defects in heme synthesis. ABCB6 is a broad-spectrum porphyrin transporter that is capable of both exporting and importing heme and its precursors across the plasma membrane and outer mitochondrial membrane, respectively. Biochemical studies have demonstrated that while ABCB6 influences the antioxidant system by reducing the levels of reactive oxygen species, the exact mechanism is currently unknown, though effects on heme synthesis are likely. Furthermore, it is unknown what biochemical or cellular signals determine where ABCB6 localizes in the cell. This review highlights the major recent findings on ABCB6 and focuses on details of its structure, mechanism, transport, contributions to cellular stress, and current clinical implications.
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Affiliation(s)
- Rebba C Boswell-Casteel
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, Tennessee, 38105-2794, USA
| | - Yu Fukuda
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, Tennessee, 38105-2794, USA
| | - John D Schuetz
- Department of Pharmaceutical Sciences, St. Jude Children's Research Hospital, 262 Danny Thomas Place, Memphis, Tennessee, 38105-2794, USA.
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15
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Mutation in human CLPX elevates levels of δ-aminolevulinate synthase and protoporphyrin IX to promote erythropoietic protoporphyria. Proc Natl Acad Sci U S A 2017; 114:E8045-E8052. [PMID: 28874591 DOI: 10.1073/pnas.1700632114] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Loss-of-function mutations in genes for heme biosynthetic enzymes can give rise to congenital porphyrias, eight forms of which have been described. The genetic penetrance of the porphyrias is clinically variable, underscoring the role of additional causative, contributing, and modifier genes. We previously discovered that the mitochondrial AAA+ unfoldase ClpX promotes heme biosynthesis by activation of δ-aminolevulinate synthase (ALAS), which catalyzes the first step of heme synthesis. CLPX has also been reported to mediate heme-induced turnover of ALAS. Here we report a dominant mutation in the ATPase active site of human CLPX, p.Gly298Asp, that results in pathological accumulation of the heme biosynthesis intermediate protoporphyrin IX (PPIX). Amassing of PPIX in erythroid cells promotes erythropoietic protoporphyria (EPP) in the affected family. The mutation in CLPX inactivates its ATPase activity, resulting in coassembly of mutant and WT protomers to form an enzyme with reduced activity. The presence of low-activity CLPX increases the posttranslational stability of ALAS, causing increased ALAS protein and ALA levels, leading to abnormal accumulation of PPIX. Our results thus identify an additional molecular mechanism underlying the development of EPP and further our understanding of the multiple mechanisms by which CLPX controls heme metabolism.
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16
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Barman-Aksoezen J, Girelli D, Aurizi C, Schneider-Yin X, Campostrini N, Barbieri L, Minder EI, Biolcati G. Disturbed iron metabolism in erythropoietic protoporphyria and association of GDF15 and gender with disease severity. J Inherit Metab Dis 2017; 40:433-441. [PMID: 28185024 DOI: 10.1007/s10545-017-0017-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 12/31/2016] [Accepted: 01/16/2017] [Indexed: 01/01/2023]
Abstract
Patients with erythropoietic protoporphyria (EPP) have reduced activity of the enzyme ferrochelatase that catalyzes the insertion of iron into protoporphyrin IX (PPIX) to form heme. As the result of ferrochelatase deficiency, PPIX accumulates and causes severe photosensitivity. Among different patients, the concentration of PPIX varies considerably. In addition to photosensitivity, patients frequently exhibit low serum iron and a microcytic hypochromic anemia. The aims of this study were to (1) search for factors related to PPIX concentration in EPP, and (2) characterize anemia in EPP, i.e., whether it is the result of an absolute iron deficiency or the anemia of chronic disease (ACD). Blood samples from 67 EPP patients (51 Italian and 16 Swiss) and 21 healthy volunteers were analyzed. EPP patients had lower ferritin (p = 0.021) and hepcidin (p = 0.031) concentrations and higher zinc-protoporphyrin (p < 0.0001) and soluble-transferrin-receptor (p = 0.0007) concentrations compared with controls. This indicated that anemia in EPP resulted from an absolute iron deficiency. Among EPP patients, PPIX concentrations correlated with both growth differentiation factor (GDF) 15 (p = 0.012) and male gender (p = 0.015). Among a subgroup of patients who were iron replete, hemoglobin levels were normal, which suggested that iron but not ferrochelatase is the limiting factor in heme synthesis of individuals with EPP.
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Affiliation(s)
| | - Domenico Girelli
- Department of Medicine, Section of Internal Medicine, University of Verona, Verona, Italy
| | - Caterina Aurizi
- Porphyria Centre San Gallicano Dermatological Institute IRCCS, Rome, Italy
| | | | - Natascia Campostrini
- Department of Medicine, Section of Internal Medicine, University of Verona, Verona, Italy
| | - Luca Barbieri
- Porphyria Centre San Gallicano Dermatological Institute IRCCS, Rome, Italy
| | - Elisabeth I Minder
- Institute for Laboratory Medicine, Stadtspital Triemli, Zürich, Switzerland.
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17
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Millot S, Delaby C, Moulouel B, Lefebvre T, Pilard N, Ducrot N, Ged C, Lettéron P, de Franceschi L, Deybach JC, Beaumont C, Gouya L, De Verneuil H, Lyoumi S, Puy H, Karim Z. Hemolytic anemia repressed hepcidin level without hepatocyte iron overload: lesson from Günther disease model. Haematologica 2016; 102:260-270. [PMID: 28143953 DOI: 10.3324/haematol.2016.151621] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 10/28/2016] [Indexed: 01/08/2023] Open
Abstract
Hemolysis occurring in hematologic diseases is often associated with an iron loading anemia. This iron overload is the result of a massive outflow of hemoglobin into the bloodstream, but the mechanism of hemoglobin handling has not been fully elucidated. Here, in a congenital erythropoietic porphyria mouse model, we evaluate the impact of hemolysis and regenerative anemia on hepcidin synthesis and iron metabolism. Hemolysis was confirmed by a complete drop in haptoglobin, hemopexin and increased plasma lactate dehydrogenase, an increased red blood cell distribution width and osmotic fragility, a reduced half-life of red blood cells, and increased expression of heme oxygenase 1. The erythropoiesis-induced Fam132b was increased, hepcidin mRNA repressed, and transepithelial iron transport in isolated duodenal loops increased. Iron was mostly accumulated in liver and spleen macrophages but transferrin saturation remained within the normal range. The expression levels of hemoglobin-haptoglobin receptor CD163 and hemopexin receptor CD91 were drastically reduced in both liver and spleen, resulting in heme- and hemoglobin-derived iron elimination in urine. In the kidney, the megalin/cubilin endocytic complex, heme oxygenase 1 and the iron exporter ferroportin were induced, which is reminiscent of significant renal handling of hemoglobin-derived iron. Our results highlight ironbound hemoglobin urinary clearance mechanism and strongly suggest that, in addition to the sequestration of iron in macrophages, kidney may play a major role in protecting hepatocytes from iron overload in chronic hemolysis.
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Affiliation(s)
- Sarah Millot
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Service Odontologie, Hôpital Universitaire, Université de Montpellier, France.,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Constance Delaby
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France.,Institut de Médecine Régénératrice et de Biothérapie-Hôpital Saint Eloi CHU Montpellier, Université de Montpellier, France
| | - Boualem Moulouel
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Thibaud Lefebvre
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | - Nathalie Pilard
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France
| | - Nicolas Ducrot
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Cécile Ged
- INSERM, Biothérapies des Maladies Génétiques et Cancers, U1035, F-33000 Bordeaux, France
| | - Philippe Lettéron
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France
| | - Lucia de Franceschi
- Department of Clinical and Experimental Medicine, Section of Internal Medicine, University of Verona, Italy
| | - Jean Charles Deybach
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France.,Institut de Médecine Régénératrice et de Biothérapie-Hôpital Saint Eloi CHU Montpellier, Université de Montpellier, France
| | - Carole Beaumont
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
| | - Laurent Gouya
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | - Hubert De Verneuil
- Assistance Publique-Hôpitaux de Paris (AP-HP), Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | - Saïd Lyoumi
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France.,Université Versailles Saint Quentin en Yvelines, France
| | - Hervé Puy
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France .,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France.,Assistance Publique-Hôpitaux de Paris (AP-HP), Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
| | - Zoubida Karim
- INSERM U1149/ERL CNRS 8252, Centre de Recherche sur l'Inflammation Paris Montmartre, 75018 Paris, France .,Université Paris Diderot, Bichat site, Paris, France.,Laboratory of Excellence, GR-Ex, Paris, France
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18
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Peoc'h K, Martin-Schmitt C, Talbi N, Deybach JC, Gouya L, Puy H. [Porphyrias and haem related disorders]. Rev Med Interne 2016; 37:173-85. [PMID: 26774916 DOI: 10.1016/j.revmed.2015.12.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 12/05/2015] [Indexed: 10/22/2022]
Abstract
The hereditary porphyrias comprise a group of eight metabolic disorders of the haem biosynthesis pathway characterised by acute neurovisceral symptoms, skin lesions or both. Each porphyria is caused by abnormal function of a separate enzymatic step resulting in a specific accumulation of haem precursors. Seven porphyrias are the consequence of a partial enzyme deficiency while a gain of function mechanism has been recently characterised in a novel porphyria. Acute porphyrias present with severe abdominal pain, nausea, constipation, confusion and seizure, which may be life threatening. Cutaneous porphyrias can be present with either acute painful photosensitivity or skin fragility and blisters. Rare recessive porphyrias usually manifest in early childhood with either severe chronic neurological symptoms or chronic haemolysis and severe cutaneous photosensitivity. Porphyrias are still underdiagnosed, but once they are suspected, and depending on the clinical presentation, a specific and simple front line test allows the diagnosis in all symptomatic patients. Diagnosis is essential to institute as soon as possible a specific treatment. Screening families to identify presymptomatic carriers is crucial to prevent chronic complications and overt disease by counselling on avoiding potential precipitants.
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Affiliation(s)
- K Peoc'h
- Centre français des porphyries, hôpital Louis-Mourier, Assistance publique-Hôpitaux de Paris (AP-HP), 92701 Colombes, France; U1149/ERL CNRS 8252, centre de recherche sur l'inflammation Paris, Montmartre, université Paris Diderot, site Bichat, Sorbonne Paris Cité, 75004 Paris, France
| | - C Martin-Schmitt
- Centre français des porphyries, hôpital Louis-Mourier, Assistance publique-Hôpitaux de Paris (AP-HP), 92701 Colombes, France; Laboratoire d'excellence, GR-Ex, 75015 Paris, France
| | - N Talbi
- Centre français des porphyries, hôpital Louis-Mourier, Assistance publique-Hôpitaux de Paris (AP-HP), 92701 Colombes, France
| | - J-C Deybach
- Centre français des porphyries, hôpital Louis-Mourier, Assistance publique-Hôpitaux de Paris (AP-HP), 92701 Colombes, France; Laboratoire d'excellence, GR-Ex, 75015 Paris, France
| | - L Gouya
- Centre français des porphyries, hôpital Louis-Mourier, Assistance publique-Hôpitaux de Paris (AP-HP), 92701 Colombes, France; Laboratoire d'excellence, GR-Ex, 75015 Paris, France
| | - H Puy
- Centre français des porphyries, hôpital Louis-Mourier, Assistance publique-Hôpitaux de Paris (AP-HP), 92701 Colombes, France; Laboratoire d'excellence, GR-Ex, 75015 Paris, France.
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19
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Doty RT, Phelps SR, Shadle C, Sanchez-Bonilla M, Keel SB, Abkowitz JL. Coordinate expression of heme and globin is essential for effective erythropoiesis. J Clin Invest 2015; 125:4681-91. [PMID: 26551679 DOI: 10.1172/jci83054] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2015] [Accepted: 10/08/2015] [Indexed: 01/27/2023] Open
Abstract
Erythropoiesis requires rapid and extensive hemoglobin production. Heme activates globin transcription and translation; therefore, heme synthesis must precede globin synthesis. As free heme is a potent inducer of oxidative damage, its levels within cellular compartments require stringent regulation. Mice lacking the heme exporter FLVCR1 have a severe macrocytic anemia; however, the mechanisms that underlie erythropoiesis dysfunction in these animals are unclear. Here, we determined that erythropoiesis failure occurs in these animals at the CFU-E/proerythroblast stage, a point at which the transferrin receptor (CD71) is upregulated, iron is imported, and heme is synthesized--before ample globin is produced. From the CFU-E/proerythroblast (CD71(+) Ter119(-) cells) stage onward, erythroid progenitors exhibited excess heme content, increased cytoplasmic ROS, and increased apoptosis. Reducing heme synthesis in FLVCR1-defient animals via genetic and biochemical approaches improved the anemia, implying that heme excess causes, and is not just associated with, the erythroid marrow failure. Expression of the cell surface FLVCR1 isoform, but not the mitochondrial FLVCR1 isoform, restored normal rbc production, demonstrating that cellular heme export is essential. Together, these studies provide insight into how heme is regulated to allow effective erythropoiesis, show that erythropoiesis fails when heme is excessive, and emphasize the importance of evaluating Ter119(-) erythroid cells when studying erythroid marrow failure in murine models.
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20
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Bossi K, Lee J, Schmeltzer P, Holburton E, Groseclose G, Besur S, Hwang S, Bonkovsky HL. Homeostasis of iron and hepcidin in erythropoietic protoporphyria. Eur J Clin Invest 2015. [PMID: 26199063 DOI: 10.1111/eci.12503] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
BACKGROUND Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are genetic abnormalities of heme synthesis that result in excess production of protoporphyrin and that manifest as severe photosensitivity. These disorders are often associated with iron deficiency anaemia (IDA). Our aim was to determine whether hepcidin is increased in EPP/XLP patients, resulting in decreased enteral iron absorption and IDA. MATERIAL AND METHODS Eight subjects with EPP, one with XLP and nine controls had baseline blood and urine samples collected, and thereafter were given oral ferrous sulphate (660 mg). Post-iron blood and urine samples were collected at 2, 4, 6 and 8 h. Blood counts, serum cytokines, ferritin and iron studies were analysed at baseline. Serum iron studies, serum and urine hepcidin, and erythropoietin (Epo) were analysed at baseline and subsequent time points. RESULTS At baseline, EPP-XLP subjects had lower mean blood haemoglobin (13·9/15·3 g/dL) and serum ferritin (31·6/115 ng/mL) than controls. Serum iron levels increased markedly in both cohorts. Mean serum and urine hepcidin levels were significantly lower in the EPP-XLP group at 4 and 8 h post-iron (serum - 4 h, 3·79/26·6, 8 h, 5·79/34·6 nM; urine - 4 h, 0·85/2·50, 8 h, 1·44/6·63 nM/mM creatinine). Serum cytokines and Epo were normal and not different between groups. CONCLUSIONS We conclude that serum and urine hepcidin are not inappropriately increased in EPP/XLP subjects at baseline and do not increase over time as serum iron increases after oral ferrous sulphate. Levels of serum cytokines and Epo are normal in EPP/XLP. The molecular basis for the iron-deficient phenotype in EPP/XLP remains unknown.
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Affiliation(s)
- Krista Bossi
- The Liver-Biliary-Pancreatic Center, Carolinas HealthCare System, Charlotte, NC, USA
| | - Jingyun Lee
- Department of Research, Carolinas HealthCare System, Charlotte, NC, USA
| | - Paul Schmeltzer
- The Liver-Biliary-Pancreatic Center, Carolinas HealthCare System, Charlotte, NC, USA.,Department of Medicine, Carolinas HealthCare System, Charlotte, NC, USA
| | - Eric Holburton
- The Liver-Biliary-Pancreatic Center, Carolinas HealthCare System, Charlotte, NC, USA.,Department of Research, Carolinas HealthCare System, Charlotte, NC, USA
| | - Gale Groseclose
- The Liver-Biliary-Pancreatic Center, Carolinas HealthCare System, Charlotte, NC, USA
| | - Siddesh Besur
- The Liver-Biliary-Pancreatic Center, Carolinas HealthCare System, Charlotte, NC, USA.,Department of Medicine, Carolinas HealthCare System, Charlotte, NC, USA
| | - Sunil Hwang
- Department of Research, Carolinas HealthCare System, Charlotte, NC, USA
| | - Herbert L Bonkovsky
- The Liver-Biliary-Pancreatic Center, Carolinas HealthCare System, Charlotte, NC, USA.,Department of Research, Carolinas HealthCare System, Charlotte, NC, USA.,Department of Medicine, Carolinas HealthCare System, Charlotte, NC, USA
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21
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Karim Z, Lyoumi S, Nicolas G, Deybach JC, Gouya L, Puy H. Porphyrias: A 2015 update. Clin Res Hepatol Gastroenterol 2015; 39:412-25. [PMID: 26142871 DOI: 10.1016/j.clinre.2015.05.009] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 05/15/2015] [Accepted: 05/19/2015] [Indexed: 02/08/2023]
Abstract
The hereditary porphyrias comprise a group of eight metabolic disorders of the heme biosynthesis pathway. Each porphyria is caused by abnormal function at a separate enzymatic step resulting in a specific accumulation of heme precursors. Porphyrias are classified as hepatic or erythropoietic, based on the organ system in which heme precursors (δ-aminolevulinic acid [ALA], porphobilinogen and porphyrins) are overproduced. Clinically, porphyrias are characterized by acute neurovisceral symptoms, skin lesions or both. However, most if not all the porphyrias impair hepatic or gastrointestinal function. Acute hepatic porphyrias present with severe abdominal pain, nausea, constipation, confusion and seizure, which may be life threatening, and patients are at risk of hepatocellular carcinoma without cirrhosis. Porphyria Cutanea presents with skin fragility and blisters, and patients are at risk of hepatocellular carcinoma with liver iron overload. Erythropoietic protoporphyria and X-linked protoporphyria present with acute painful photosensitivity, and patients are at risk of acute liver failure. Altogether, porphyrias are still underdiagnosed, but once they are suspected, early diagnosis based on measurement of biochemical metabolites that accumulate in the blood, urine, or feces is essential so specific treatment can be started as soon as possible and long-term liver complications are prevented. Screening families to identify presymptomatic carriers is also crucial to prevent overt disease and chronic hepatic complications.
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Affiliation(s)
- Zoubida Karim
- INSERM U1149 CNRS ERL 8252, centre de recherche sur l'inflammation, 16, rue Henri-Huchard, 75018 Paris, France; Laboratory of excellence, GR-Ex, 24, Boulevard du Montparnasse, 75015 Paris, France
| | - Said Lyoumi
- INSERM U1149 CNRS ERL 8252, centre de recherche sur l'inflammation, 16, rue Henri-Huchard, 75018 Paris, France; Laboratory of excellence, GR-Ex, 24, Boulevard du Montparnasse, 75015 Paris, France; Université Versailles-Saint-Quentin, 55, Avenue de Paris, 78000 Versailles, France
| | - Gael Nicolas
- INSERM U1149 CNRS ERL 8252, centre de recherche sur l'inflammation, 16, rue Henri-Huchard, 75018 Paris, France; Laboratory of excellence, GR-Ex, 24, Boulevard du Montparnasse, 75015 Paris, France
| | - Jean-Charles Deybach
- INSERM U1149 CNRS ERL 8252, centre de recherche sur l'inflammation, 16, rue Henri-Huchard, 75018 Paris, France; Université Versailles-Saint-Quentin, 55, Avenue de Paris, 78000 Versailles, France; Université Paris Diderot, site Bichat, Sorbonne Paris Cité, 75018 Paris, France; Centre français des porphyries, hôpital Louis-Mourier, AP-HP, 92701 Colombes, France
| | - Laurent Gouya
- INSERM U1149 CNRS ERL 8252, centre de recherche sur l'inflammation, 16, rue Henri-Huchard, 75018 Paris, France; Université Versailles-Saint-Quentin, 55, Avenue de Paris, 78000 Versailles, France; Université Paris Diderot, site Bichat, Sorbonne Paris Cité, 75018 Paris, France; Centre français des porphyries, hôpital Louis-Mourier, AP-HP, 92701 Colombes, France
| | - Hervé Puy
- INSERM U1149 CNRS ERL 8252, centre de recherche sur l'inflammation, 16, rue Henri-Huchard, 75018 Paris, France; Université Versailles-Saint-Quentin, 55, Avenue de Paris, 78000 Versailles, France; Université Paris Diderot, site Bichat, Sorbonne Paris Cité, 75018 Paris, France; Centre français des porphyries, hôpital Louis-Mourier, AP-HP, 92701 Colombes, France.
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22
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Abstract
Microcytic anemia is the most common form of anemia, characterized by reduced hemoglobin (Hb) synthesis associated with decreased red blood cell volume (MCV). It is a very heterogeneous group of diseases that may be either acquired or inherited. Microcytic hypochromic anemia can result from defects in globin (hemoglobinopathies or thalassemias) or heme synthesis or in iron availability, or acquisition by the erythroid precursors. Diagnosis of microcytic anaemia appears to be important in children/adolescents, especially to set, where possible, a treatment plan on the basis of the etiology and pathogenesis. After excluding the acquired causes of microcytic anemia that represent the most frequent etiology, according to the differential diagnosis, the analysis of genetic causes, mostly hereditary, must be considered. This review will consider acquired and hereditary microcytic anemias due to heme synthesis or to iron metabolism defects and their diagnosis.
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Affiliation(s)
- Mariasole Bruno
- Department of Molecular Medicine and Medical Biotechnology, University Federico II, Naples, Italy; CEINGE, Advanced Biotechnologies, Naples, Italy; Department of Medicine, Section of Internal Medicine, University of Verona, AOUI-Policlinico GB Rossi, 37134 Verona, Italy
| | - Luigia De Falco
- Department of Molecular Medicine and Medical Biotechnology, University Federico II, Naples, Italy; CEINGE, Advanced Biotechnologies, Naples, Italy
| | - Achille Iolascon
- Department of Molecular Medicine and Medical Biotechnology, University Federico II, Naples, Italy; CEINGE, Advanced Biotechnologies, Naples, Italy.
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23
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Barman-Aksözen J, Minder EI, Schubiger C, Biolcati G, Schneider-Yin X. In ferrochelatase-deficient protoporphyria patients, ALAS2 expression is enhanced and erythrocytic protoporphyrin concentration correlates with iron availability. Blood Cells Mol Dis 2015; 54:71-7. [DOI: 10.1016/j.bcmd.2014.07.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 07/25/2014] [Indexed: 11/15/2022]
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24
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Red cells from ferrochelatase-deficient erythropoietic protoporphyria patients are resistant to growth of malarial parasites. Blood 2014; 125:534-41. [PMID: 25414439 DOI: 10.1182/blood-2014-04-567149] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Many red cell polymorphisms are a result of selective pressure by the malarial parasite. Here, we add another red cell disease to the panoply of erythrocytic changes that give rise to resistance to malaria. Erythrocytes from individuals with erythropoietic protoporphyria (EPP) have low levels of the final enzyme in the heme biosynthetic pathway, ferrochelatase. Cells from these patients are resistant to the growth of Plasmodium falciparum malarial parasites. This phenomenon is due to the absence of ferrochelatase and not an accumulation of substrate, as demonstrated by the normal growth of P falciparum parasites in the EPP phenocopy, X-linked dominant protoporphyria, which has elevated substrate, and normal ferrochelatase levels. This observation was replicated in a mouse strain with a hypomorphic mutation in the murine ferrochelatase gene. The parasite enzyme is not essential for parasite growth as Plasmodium berghei parasites carrying a complete deletion of the ferrochelatase gene grow normally in erythrocytes, which confirms previous studies. That ferrochelatase is essential to parasite growth was confirmed by showing that inhibition of ferrochelatase using the specific competitive inhibitor, N-methylprotoporphyrin, produced a potent growth inhibition effect against cultures of P falciparum. This raises the possibility of targeting human ferrochelatase in a host-directed antimalarial strategy.
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25
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Singh N, Haldar S, Tripathi AK, Horback K, Wong J, Sharma D, Beserra A, Suda S, Anbalagan C, Dev S, Mukhopadhyay CK, Singh A. Brain iron homeostasis: from molecular mechanisms to clinical significance and therapeutic opportunities. Antioxid Redox Signal 2014; 20:1324-63. [PMID: 23815406 PMCID: PMC3935772 DOI: 10.1089/ars.2012.4931] [Citation(s) in RCA: 141] [Impact Index Per Article: 14.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Iron has emerged as a significant cause of neurotoxicity in several neurodegenerative conditions, including Alzheimer's disease (AD), Parkinson's disease (PD), sporadic Creutzfeldt-Jakob disease (sCJD), and others. In some cases, the underlying cause of iron mis-metabolism is known, while in others, our understanding is, at best, incomplete. Recent evidence implicating key proteins involved in the pathogenesis of AD, PD, and sCJD in cellular iron metabolism suggests that imbalance of brain iron homeostasis associated with these disorders is a direct consequence of disease pathogenesis. A complete understanding of the molecular events leading to this phenotype is lacking partly because of the complex regulation of iron homeostasis within the brain. Since systemic organs and the brain share several iron regulatory mechanisms and iron-modulating proteins, dysfunction of a specific pathway or selective absence of iron-modulating protein(s) in systemic organs has provided important insights into the maintenance of iron homeostasis within the brain. Here, we review recent information on the regulation of iron uptake and utilization in systemic organs and within the complex environment of the brain, with particular emphasis on the underlying mechanisms leading to brain iron mis-metabolism in specific neurodegenerative conditions. Mouse models that have been instrumental in understanding systemic and brain disorders associated with iron mis-metabolism are also described, followed by current therapeutic strategies which are aimed at restoring brain iron homeostasis in different neurodegenerative conditions. We conclude by highlighting important gaps in our understanding of brain iron metabolism and mis-metabolism, particularly in the context of neurodegenerative disorders.
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Affiliation(s)
- Neena Singh
- 1 Department of Pathology, Case Western Reserve University , Cleveland, Ohio
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26
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Abstract
Iron is a redox active metal which is abundant in the Earth's crust. It has played a key role in the evolution of living systems and as such is an essential element in a wide range of biological phenomena, being critical for the function of an enormous array of enzymes, energy transduction mechanisms, and oxygen carriers. The redox nature of iron renders the metal toxic in excess and consequently all biological organisms carefully control iron levels. In this overview the mechanisms adopted by man to control body iron levels are described.Low body iron levels are related to anemia which can be treated by various forms of iron fortification and supplementation. Elevated iron levels can occur systemically or locally, each giving rise to specific symptoms. Systemic iron overload results from either the hyperabsorption of iron or regular blood transfusion and can be treated by the use of a selection of iron chelating molecules. The symptoms of many forms of neurodegeneration are associated with elevated levels of iron in certain regions of the brain and iron chelation therapy is beginning to find an application in the treatment of such diseases. Iron chelators have also been widely investigated for the treatment of cancer, tuberculosis, and malaria. In these latter studies, selective removal of iron from key enzymes or iron binding proteins is sought. Sufficient selectivity between the invading organism and the host has yet to be established for such chelators to find application in the clinic.Iron chelation for systemic iron overload and iron supplementation therapy for the treatment of various forms of anemia are now established procedures in clinical medicine. Chelation therapy may find an important role in the treatment of various neurodegenerative diseases in the near future.
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27
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Camaschella C. How I manage patients with atypical microcytic anaemia. Br J Haematol 2012; 160:12-24. [PMID: 23057559 DOI: 10.1111/bjh.12081] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2012] [Accepted: 09/07/2012] [Indexed: 01/19/2023]
Abstract
Microcytic hypochromic anaemias are a result of defective iron handling by erythroblasts that decrease the haemoglobin content per red cell. Recent advances in our knowledge of iron metabolism and its homeostasis have led to the discovery of novel inherited anaemias that need to be distinguished from common iron deficiency or other causes of microcytosis. These atypical microcytic anaemias can be classified as: (i) defects of intestinal iron absorption (ii) disorders of the transferrin receptor cycle that impair erythroblast iron uptake (iii) defects of mitochondrial iron utilization for haem or iron sulphur cluster synthesis and (iv) defects of iron recycling. A careful patient history and evaluation of laboratory tests may enable these rare conditions to be distinguished from the more common iron deficiency anaemia. Molecular studies allow distinction of the different types, a prerequisite for differentiated therapy.
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Affiliation(s)
- Clara Camaschella
- Vita-Salute University and San Raffaele Scientific Institute, Via Olgettina 60, Milan, Italy.
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28
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Bartnikas TB, Fleming MD, Schmidt PJ. Murine mutants in the study of systemic iron metabolism and its disorders: an update on recent advances. BIOCHIMICA ET BIOPHYSICA ACTA 2012; 1823:1444-50. [PMID: 22306267 PMCID: PMC3360922 DOI: 10.1016/j.bbamcr.2012.01.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 01/09/2012] [Accepted: 01/18/2012] [Indexed: 02/08/2023]
Abstract
Many past and recent advances in the field of iron metabolism have relied upon the use of mouse models of disease. These models have arisen spontaneously in breeder colonies or have been engineered for global or conditional ablation or overexpression of select genes. Full phenotypic characterization of these models typically involves maintenance on iron-loaded or -deficient diets, treatment with oxidative or hemolytic agents, breeding to other mutant lines or other stresses. In this review, we focus on systemic iron biology and the contributions that mouse model-based studies have made to the field. We have divided the field into three broad areas of research: dietary iron absorption, regulation of hepcidin expression and cellular iron metabolism. For each area, we begin with an overview of the current understanding of key molecular and cellular determinants then discuss recent advances. Finally, we conclude with brief comments on prospects for future study. This article is part of a Special Issue entitled: Cell Biology of Metals.
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29
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Petersen A, Philipsen P, Wulf H. Zinc sulphate: a new concept of treatment of erythropoietic protoporphyria. Br J Dermatol 2012; 166:1129-31. [DOI: 10.1111/j.1365-2133.2011.10715.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- A.B. Petersen
- Department of Dermatology, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
E‐mail:
| | - P.A. Philipsen
- Department of Dermatology, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
E‐mail:
| | - H.C. Wulf
- Department of Dermatology, Copenhagen University Hospital, Bispebjerg Hospital, Copenhagen, Denmark
E‐mail:
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30
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Abstract
Murine models have made valuable contributions to our understanding of iron metabolism. Investigation of mice with inherited forms of anemia has led to the discovery of novel proteins involved in iron homeostasis. A growing number of murine models are being developed to investigate mitochondrial iron metabolism. Mouse strains are available for the major forms of hereditary hemochromatosis. Findings in murine models support the concept that the pathogenesis of nearly all forms of hereditary hemochromatosis involves inappropriately low expression of hepcidin. The availability of mice with floxed iron-related genes allows the study of the in vivo consequences of cell-selective deletion of these genes.
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Affiliation(s)
- Robert E Fleming
- Departments of Pediatrics and Biochemistry & Molecular Biology, Saint Louis University School of Medicine, St. Louis, MO 63104, USA.
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31
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Lyoumi S, Abitbol M, Rainteau D, Karim Z, Bernex F, Oustric V, Millot S, Lettéron P, Heming N, Guillmot L, Montagutelli X, Berdeaux G, Gouya L, Poupon R, Deybach JC, Beaumont C, Puy H. Protoporphyrin retention in hepatocytes and Kupffer cells prevents sclerosing cholangitis in erythropoietic protoporphyria mouse model. Gastroenterology 2011; 141:1509-19, 1519.e1-3. [PMID: 21762662 DOI: 10.1053/j.gastro.2011.06.078] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2010] [Revised: 06/14/2011] [Accepted: 06/28/2011] [Indexed: 12/02/2022]
Abstract
BACKGROUND & AIMS Chronic, progressive hepatobiliary disease is the most severe complication of erythropoietic protoporphyria (EPP) and can require liver transplantation, although the mechanisms that lead to liver failure are unknown. We characterized protoporphyrin-IX (PPIX)-linked hepatobiliary disease in BALB/c and C57BL/6 (Fechm1Pas) mice with mutations in ferrochelatase as models for EPP. METHODS Fechm1Pas and wild-type (control) mice were studied at 12-14 weeks of age. PPIX was quantified; its distribution in the liver, serum levels of lipoprotein-X, liver histology, contents of bile salt and cholesterol phospholipids, and expression of genes were compared in mice of the BALB/c and C57BL/6 backgrounds. The in vitro binding affinity of PPIX for bile components was determined. RESULTS Compared with mice of the C57BL/6 background, BALB/c Fechm1Pas mice had a more severe pattern of cholestasis, fibrosis with portoportal bridging, bile acid regurgitation, sclerosing cholangitis, and hepatolithiasis. In C57BL/6 Fechm1Pas mice, PPIX was sequestrated mainly in the cytosol of hepatocytes and Kupffer cells, whereas, in BALB/c Fechm1Pas mice, PPIX was localized within enlarged bile canaliculi. Livers of C57BL/6 Fechm1Pas mice were protected through a combination of lower efflux of PPIX and reduced synthesis and export of bile acid. CONCLUSIONS PPIX binds to bile components and disrupts the physiologic equilibrium of phospholipids, bile acids, and cholesterol in bile. This process might be involved in pathogenesis of sclerosing cholangitis from EPP; a better understanding might improve diagnosis and development of reagents to treat or prevent liver failure in patients with EPP.
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Affiliation(s)
- Saïd Lyoumi
- INSERM U773, Centre de Recherche Biomédicale Bichat Beaujon CRB3, Université Paris Diderot, site Bichat, Centre de reference des maladies inflammatoires des voies biliaires, service d’Hépatologie-Gastroentérologie, Hôpital Saint Antoine, Paris, France
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32
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Talbot AL, Bullock GC, Delehanty LL, Sattler M, Zhao ZJ, Goldfarb AN. Aconitase regulation of erythropoiesis correlates with a novel licensing function in erythropoietin-induced ERK signaling. PLoS One 2011; 6:e23850. [PMID: 21887333 PMCID: PMC3161794 DOI: 10.1371/journal.pone.0023850] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 07/26/2011] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND Erythroid development requires the action of erythropoietin (EPO) on committed progenitors to match red cell output to demand. In this process, iron acts as a critical cofactor, with iron deficiency blunting EPO-responsiveness of erythroid progenitors. Aconitase enzymes have recently been identified as possible signal integration elements that couple erythropoiesis with iron availability. In the current study, a regulatory role for aconitase during erythropoiesis was ascertained using a direct inhibitory strategy. METHODOLOGY/PRINCIPAL FINDINGS In C57BL/6 mice, infusion of an aconitase active-site inhibitor caused a hypoplastic anemia and suppressed responsiveness to hemolytic challenge. In a murine model of polycythemia vera, aconitase inhibition rapidly normalized red cell counts, but did not perturb other lineages. In primary erythroid progenitor cultures, aconitase inhibition impaired proliferation and maturation but had no effect on viability or ATP levels. This inhibition correlated with a blockade in EPO signal transmission specifically via ERK, with preservation of JAK2-STAT5 and Akt activation. Correspondingly, a physical interaction between ERK and mitochondrial aconitase was identified and found to be sensitive to aconitase inhibition. CONCLUSIONS/SIGNIFICANCE Direct aconitase inhibition interferes with erythropoiesis in vivo and in vitro, confirming a lineage-selective regulatory role involving its enzymatic activity. This inhibition spares metabolic function but impedes EPO-induced ERK signaling and disturbs a newly identified ERK-aconitase physical interaction. We propose a model in which aconitase functions as a licensing factor in ERK-dependent proliferation and differentiation, thereby providing a regulatory input for iron in EPO-dependent erythropoiesis. Directly targeting aconitase may provide an alternative to phlebotomy in the treatment of polycythemia vera.
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Affiliation(s)
- Anne-Laure Talbot
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Grant C. Bullock
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Lorrie L. Delehanty
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
| | - Martin Sattler
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, Massachusetts, United States of America
| | - Zhizhuang Joe Zhao
- Department of Pathology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Adam N. Goldfarb
- Department of Pathology, University of Virginia School of Medicine, Charlottesville, Virginia, United States of America
- * E-mail:
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Pallure V, Dereure O. Photosensibilité et anémie : penser à la protoporphyrie érythropoïétique. Ann Dermatol Venereol 2011; 138:54-5. [DOI: 10.1016/j.annder.2010.08.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Minder EI, Haldemann AR, Schneider-Yin X. Exacerbation of erythropoietic protoporphyria by hyperthyroidism. J Inherit Metab Dis 2010; 33 Suppl 3:S465-9. [PMID: 21069463 DOI: 10.1007/s10545-010-9234-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2010] [Revised: 10/06/2010] [Accepted: 10/14/2010] [Indexed: 11/27/2022]
Abstract
Erythropoietic protoporphyria (EPP) is a hereditary disorder caused by deficiency of ferrochelatase, the last enzyme in the heme biosynthetic pathway. The majority of EPP patients present with a clinical symptom of painful phototoxicity. Liver damage, the most serious complication of EPP, occurs in <5% of the patients. This report describes a case of an EPP patient who complained of worsening cutaneous symptoms, nervousness, and insomnia. Laboratory tests showed highly increased protoporphyrin concentration in erythrocytes and elevated serum transaminases that are indicative of EPP-related liver damage. The subsequent finding of decreased serum thyroid-stimulating hormone (TSH) and increased free triiodothyronine (FT3) and free thyroxine (FT4) concentrations, as well antibodies against both thyroid peroxidase (TPO) and TSH receptors, led to the diagnosis of Graves' disease. The patient received 500 MBq of radioiodine (I(131)). Three months after the radioactive iodine therapy, the thyroid volume was reduced to 30% of pretherapeutic volume. Although the patient was slightly hypothyroidic, his liver enzymes returned to normal, his erythrocytic protoporphyrin concentration dropped fivefold, and his skin symptoms improved dramatically. The coexistence of Graves' disease and EPP is a statistically rare event as, besides our patient, there was one additional case reported in the literature. Although the exact mechanism whereby Graves' disease interacts with EPP is yet to be explored, we recommend testing thyroid function in EPP patients with liver complication to exclude hyperthyroidism as a potential cause.
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35
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Schmitt C, Ducamp S, Gouya L, Deybach JC, Puy H. [Inheritance in erythropoietic protoporphyria]. ACTA ACUST UNITED AC 2010; 58:372-80. [PMID: 20850938 DOI: 10.1016/j.patbio.2010.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Accepted: 01/29/2010] [Indexed: 01/10/2023]
Abstract
Erythropoietic protoporphyria (EPP) is an inherited disorder of heme biosynthesis that results from an accumulation of protoporphyrin IX in erythroid cells, plasma, skin and liver. EPP leads to acute photosensitivity and, in about 2% of patients, liver disease. EPP is a complex syndrome in which two genes are independently involved: FECH and ALAS2. More than 96% of unrelated EPP patients have ferrochelatase (FECH) deficiency (MIM 177000). Four percent of them present with autosomal recessive inheritance with two mutated FECH alleles. In dominant cases (95%) the inheritance of a common hypomorphic IVS3-48C FECH allele trans to a deleterious FECH mutation reduces FECH activity below a critical threshold. The frequency of the IVS3-48C allele differs widely from the Japanese (45%), to Black West Africans (<1%) populations. These differences in the frequency of this single common SNP account for the prevalence of overt EPP in different countries and for the absence of EPP in Black Africans. The phylogenic origin of the IVS3-48C haplotypes strongly suggests that the IVS3-48C allele arose from a single recent mutational event that occurred 60 Kyears ago. Acquired somatic mutation of FECH secondary to myeloid disease may also exceptionally cause EPP (<1%). Finally, about 4% of unrelated EPP patients have X-linked dominant protoporphyria (XLDPP) (MIM 300752) caused by gain-of-function mutations in the ALAS2 gene leading to an increased erythroid heme biosynthesis and subsequently an accumulation of protoporphyrin without any FECH deficiency.
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Affiliation(s)
- C Schmitt
- Centre Français des Porphyries, Service de Biochimie, Hôpital Louis-Mourier, AP-HP, 178 rue des Renouillers, 92701 Colombes cedex, France
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Protective effects of crude garlic by reducing iron-mediated oxidative stress, proliferation and autophagy in rats. J Mol Histol 2010; 41:233-45. [PMID: 20700633 DOI: 10.1007/s10735-010-9283-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Accepted: 07/19/2010] [Indexed: 01/04/2023]
Abstract
The impact of garlic, known for its antioxidant activities, on iron metabolism has been poorly investigated. The aim of this work was to study the effect of crude garlic pre-treatment on iron-mediated lipid peroxidation, proliferation and autophagy for 5 weeks. Rats were fed distilled water or garlic solution (1 g/kg body weight) by gavage for the first 3 weeks as pre-treatment and received a basal diet supplemented or not with ferrous sulfate (650 mg Fe/kg diet) for the last 2 weeks of treatment. Immunohistochemistry labeling and ultrastuctural observations were used to evaluate the iron deleterious effects in the liver. Iron supplementation induced cell proliferation predominantly in non parenchymal cells comparing to hepatocytes, but not apoptosis. In addition, iron was accumulated within the hepatic lysosomes where it triggers autophagy as evidenced by the formation of autophagic vesicles detected by LC3-II staining. It also induced morphologic alterations of the mitochondrial membranes due to increased lipid peroxidation as shown by elevated iron and malondialdehyde concentrations in serum and tissues. Garlic pre-treatment reduced iron-catalyzed lipid peroxidation by decreasing the malondialdehyde level in the liver and colon and by enhancing the status of antioxidants. In addition, garlic reduced the iron-mediated cell proliferation and autophagy by lowering iron storage in the liver and protected mitochondrial membrane. Based on these results, garlic treatment significantly prevented iron-induced oxidative stress, proliferation and autophagy at both biochemical and histological levels due to its potent free radical scavenging and antioxidant properties.
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Nahdi A, Hammami I, Brasse-Lagnel C, Pilard N, Hamdaoui MH, Beaumont C, El May M. Influence of garlic or its main active component diallyl disulfide on iron bioavailability and toxicity. Nutr Res 2010; 30:85-95. [PMID: 20226993 DOI: 10.1016/j.nutres.2010.01.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Revised: 01/15/2010] [Accepted: 01/15/2010] [Indexed: 01/01/2023]
Abstract
Garlic is regularly consumed and is known to have diverse biologic activities, particularly due to its antioxidant properties. In this study, we hypothesized that crude garlic can prevent iron-mediated oxidative stress in a rat model of nutritional iron overload, and we used an in vitro model to confirm the results. For the in vivo studies, rats received a basal diet supplemented with or without carbonyl iron (3%) and were fed distilled water or garlic solution (1g/kg body weight) by gavage for 3 weeks. The presence of both garlic and iron led to a 2-fold increase in plasma iron and a 50% increase in liver iron as compared with iron alone. However, garlic did not offer any protection against iron-induced oxidative stress. Duodenal divalent metal transporter-1 mRNA expression was fully repressed by iron and by the combined treatments but was also reduced by garlic alone. To confirm these data, we tested the effect of diallyl disulfide, one of the active components in garlic, in vitro on polarized Caco-2 cells. A 24-hour treatment decreased iron uptake at the apical side of Caco-2 cells but increased the percentage of iron transfer at the basolateral side. This probably resulted from a modest induction of ferroportin mRNA and protein expression. These results suggest that garlic, when given in the presence of iron, enhances iron absorption by increasing ferroportin expression. The presence of garlic in the diet at the dose studied does not seem to protect against iron-mediated oxidative stress.
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Affiliation(s)
- Afef Nahdi
- Unité de recherche 01/UR/08-07, Laboratoire d'histologie-embryologie et biologie cellulaire, Faculté de Médecine de Tunis, Tunis, Tunisie
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Galy B, Ferring-Appel D, Sauer SW, Kaden S, Lyoumi S, Puy H, Kölker S, Gröne HJ, Hentze MW. Iron regulatory proteins secure mitochondrial iron sufficiency and function. Cell Metab 2010; 12:194-201. [PMID: 20674864 DOI: 10.1016/j.cmet.2010.06.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2009] [Revised: 04/06/2010] [Accepted: 06/02/2010] [Indexed: 12/20/2022]
Abstract
Mitochondria supply cells with ATP, heme, and iron sulfur clusters (ISC), and mitochondrial energy metabolism involves both heme- and ISC-dependent enzymes. Here, we show that mitochondrial iron supply and function require iron regulatory proteins (IRP), cytosolic RNA-binding proteins that control mRNA translation and stability. Mice lacking both IRP1 and IRP2 in their hepatocytes suffer from mitochondrial iron deficiency and dysfunction associated with alterations of the ISC and heme biosynthetic pathways, leading to liver failure and death. These results uncover a major role of the IRPs in cell biology: to ensure adequate iron supply to the mitochondrion for proper function of this critical organelle.
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Affiliation(s)
- Bruno Galy
- European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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Genome-wide identification of TAL1's functional targets: insights into its mechanisms of action in primary erythroid cells. Genome Res 2010; 20:1064-83. [PMID: 20566737 DOI: 10.1101/gr.104935.110] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Coordination of cellular processes through the establishment of tissue-specific gene expression programs is essential for lineage maturation. The basic helix-loop-helix hemopoietic transcriptional regulator TAL1 (formerly SCL) is required for terminal differentiation of red blood cells. To gain insight into TAL1 function and mechanisms of action in erythropoiesis, we performed ChIP-sequencing and gene expression analyses from primary fetal liver erythroid cells. We show that TAL1 coordinates expression of genes in most known red cell-specific processes. The majority of TAL1's genomic targets require direct DNA-binding activity. However, one-fifth of TAL1's target sequences, mainly among those showing high affinity for TAL1, can recruit the factor independently of its DNA binding activity. An unbiased DNA motif search of sequences bound by TAL1 identified CAGNTG as TAL1-preferred E-box motif in erythroid cells. Novel motifs were also characterized that may help distinguish activated from repressed genes and suggest a new mechanism by which TAL1 may be recruited to DNA. Finally, analysis of recruitment of GATA1, a protein partner of TAL1, to sequences occupied by TAL1 suggests that TAL1's binding is necessary prior or simultaneous to that of GATA1. This work provides the framework to study regulatory networks leading to erythroid terminal maturation and to model mechanisms of action of tissue-specific transcription factors.
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40
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Abstract
Human red cell differentiation requires the action of erythropoietin on committed progenitor cells. In iron deficiency, committed erythroid progenitors lose responsiveness to erythropoietin, resulting in hypoplastic anemia. To address the basis for iron regulation of erythropoiesis, we established primary hematopoietic cultures with transferrin saturation levels that restricted erythropoiesis but permitted granulopoiesis and megakaryopoiesis. Experiments in this system identified as a critical regulatory element the aconitases, multifunctional iron-sulfur cluster proteins that metabolize citrate to isocitrate. Iron restriction suppressed mitochondrial and cytosolic aconitase activity in erythroid but not granulocytic or megakaryocytic progenitors. An active site aconitase inhibitor, fluorocitrate, blocked erythroid differentiation in a manner similar to iron deprivation. Exogenous isocitrate abrogated the erythroid iron restriction response in vitro and reversed anemia progression in iron-deprived mice. The mechanism for aconitase regulation of erythropoiesis most probably involves both production of metabolic intermediates and modulation of erythropoietin signaling. One relevant signaling pathway appeared to involve protein kinase Calpha/beta, or possibly protein kinase Cdelta, whose activities were regulated by iron, isocitrate, and erythropoietin.
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Abstract
Hereditary porphyrias are a group of eight metabolic disorders of the haem biosynthesis pathway that are characterised by acute neurovisceral symptoms, skin lesions, or both. Every porphyria is caused by abnormal function of a separate enzymatic step, resulting in a specific accumulation of haem precursors. Seven porphyrias are the result of a partial enzyme deficiency, and a gain of function mechanism has been characterised in a new porphyria. Acute porphyrias present with acute attacks, typically consisting of severe abdominal pain, nausea, constipation, confusion, and seizure, and can be life-threatening. Cutaneous porphyrias present with either acute painful photosensitivity or skin fragility and blisters. Rare recessive porphyrias usually manifest in early childhood with either severe cutaneous photosensitivity and chronic haemolysis or chronic neurological symptoms with or without photosensitivity. Porphyrias are still underdiagnosed, but when they are suspected, and dependent on clinical presentation, simple first-line tests can be used to establish the diagnosis in all symptomatic patients. Diagnosis is essential to enable specific treatments to be started as soon as possible. Screening of families to identify presymptomatic carriers is crucial to decrease risk of overt disease of acute porphyrias through counselling about avoidance of potential precipitants.
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Affiliation(s)
- Hervé Puy
- Assistance Publique Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France
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Iolascon A, De Falco L, Beaumont C. Molecular basis of inherited microcytic anemia due to defects in iron acquisition or heme synthesis. Haematologica 2009; 94:395-408. [PMID: 19181781 DOI: 10.3324/haematol.13619] [Citation(s) in RCA: 113] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Microcytic anemia is the most commonly encountered anemia in general medical practice. Nutritional iron deficiency and beta thalassemia trait are the primary causes in pediatrics, whereas bleeding disorders and anemia of chronic disease are common in adulthood. Microcytic hypochromic anemia can result from a defect in globin genes, in heme synthesis, in iron availability or in iron acquisition by the erythroid precursors. These microcytic anemia can be sideroblastic or not, a trait which reflects the implications of different gene abnormalities. Iron is a trace element that may act as a redox component and therefore is integral to vital biological processes that require the transfer of electrons as in oxygen transport, oxidative phosphorylation, DNA biosynthesis and xenobiotic metabolism. However, it can also be pro-oxidant and to avoid its toxicity, iron metabolism is strictly controlled and failure of these control systems could induce iron overload or iron deficient anemia. During the past few years, several new discoveries mostly arising from human patients or mouse models have highlighted the implication of iron metabolism components in hereditary microcytic anemia, from intestinal absorption to its final inclusion into heme. In this paper we will review the new information available on the iron acquisition pathway by developing erythrocytes and its regulation, and we will consider only inherited microcytosis due to heme synthesis or to iron metabolism defects. This information could be useful in the diagnosis and classification of these microcytic anemias.
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Affiliation(s)
- Achille Iolascon
- Department of Biochemistry and Medical Biotechnologies, University Federico II, Naples, Italy.
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Kojima S, Sasaki J, Tomita M, Saka M, Ishizuka K, Kawakatsu H, Yoshida T, Kosaka T, Enomoto A, Nakashima N, Harada T. Multiple organ toxicity, including hypochromic anemia, following repeated dose oral administration of phenobarbital (PB) in rats. J Toxicol Sci 2009; 34:527-39. [DOI: 10.2131/jts.34.527] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Whatley SD, Ducamp S, Gouya L, Grandchamp B, Beaumont C, Badminton MN, Elder GH, Holme SA, Anstey AV, Parker M, Corrigall AV, Meissner PN, Hift RJ, Marsden JT, Ma Y, Mieli-Vergani G, Deybach JC, Puy H. C-terminal deletions in the ALAS2 gene lead to gain of function and cause X-linked dominant protoporphyria without anemia or iron overload. Am J Hum Genet 2008; 83:408-14. [PMID: 18760763 DOI: 10.1016/j.ajhg.2008.08.003] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2008] [Revised: 08/04/2008] [Accepted: 08/07/2008] [Indexed: 11/24/2022] Open
Abstract
All reported mutations in ALAS2, which encodes the rate-regulating enzyme of erythroid heme biosynthesis, cause X-linked sideroblastic anemia. We describe eight families with ALAS2 deletions, either c.1706-1709 delAGTG (p.E569GfsX24) or c.1699-1700 delAT (p.M567EfsX2), resulting in frameshifts that lead to replacement or deletion of the 19-20 C-terminal residues of the enzyme. Prokaryotic expression studies show that both mutations markedly increase ALAS2 activity. These gain-of-function mutations cause a previously unrecognized form of porphyria, X-linked dominant protoporphyria, characterized biochemically by a high proportion of zinc-protoporphyrin in erythrocytes, in which a mismatch between protoporphyrin production and the heme requirement of differentiating erythroid cells leads to overproduction of protoporphyrin in amounts sufficient to cause photosensitivity and liver disease.
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Abstract
Sideroblastic anaemia includes a heterogeneous group of rare conditions, characterized by decreased haem synthesis and mitochondrial iron overload, which are diagnosed by the presence of ringed sideroblasts in the bone marrow aspirate. The most frequent form is X-linked sideroblastic anaemia, caused by mutations of delta-aminolevulinic acid synthase 2 (ALAS2), the enzyme that catalyses the first and regulatory step of haem synthesis in erythroid precursors and is post-transcriptionally controlled by the iron regulatory proteins. Impaired haem production causes variable degrees of anaemia and mitochondrial iron accumulation as ringed sideroblasts. The heterogeneity and complexity of sideroblastic anaemia is explained by an increasing number of recognized molecular defects. New forms have been recognized as being linked to the deficient function of mitochondrial proteins involved in iron-sulphur cluster biogenesis, such as ABCB7 and GLRX5, which are extremely rare but represent important biological models. Local mitochondrial iron overload is present in all sideroblastic anaemias, whereas systemic iron overload occurs only in the forms because of primary or secondary deficiency of ALAS2.
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Affiliation(s)
- Clara Camaschella
- Vita-Salute San Raffaele University and San Raffaele Scientific Institute, Milan, Italy.
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Holme SA, Worwood M, Anstey AV, Elder GH, Badminton MN. Erythropoiesis and iron metabolism in dominant erythropoietic protoporphyria. Blood 2007; 110:4108-10. [PMID: 17804693 DOI: 10.1182/blood-2007-04-088120] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractErythropoietic protoporphyria (EPP) results from deficiency of ferrochelatase (FECH). Accumulation of protoporphyrin IX causes life-long acute photosensitivity. Microcytic anemia occurs in 20% to 60% of patients. We investigated 178 patients with dominant EPP confirmed by molecular analysis. Erythropoiesis was impaired in all patients; all had a downward shift in hemoglobin (Hb), and the mean decreased in males by 12 g/L (1.2 g/dL). By World Health Organization criteria, 48% of women and 33% of men were anemic. Iron stores, assessed by serum ferritin (sFn), were decreased by two-thirds, but normal serum soluble transferrin receptor-1 and iron concentrations suggested that erythropoiesis was not limited by iron supply. FECH deficiency in EPP appears to lead to a steady state in which decreased erythropoiesis is matched by reduced iron absorption and supply. This response may in part be mediated by protoporphyrin, but we found no correlation between erythrocyte protoporphyrin and Hb, sFn, total iron-binding capacity, or transferrin saturation.
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Affiliation(s)
- S Alexander Holme
- Department of Dermatology, University Hospital of Wales and School of Medicine, Cardiff University, Cardiff, United Kingdom
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