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Minder AE, Schneider-Yin X, Zulewski H, Minder CE, Minder EI. Afamelanotide Is Associated with Dose-Dependent Protective Effect from Liver Damage Related to Erythropoietic Protoporphyria. Life (Basel) 2023; 13:1066. [PMID: 37109595 PMCID: PMC10143433 DOI: 10.3390/life13041066] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 03/29/2023] [Accepted: 04/14/2023] [Indexed: 04/29/2023] Open
Abstract
In animal models, melanocyte-stimulating hormones (MSHs) protect the liver from various injuries. Erythropoietic protoporphyria (EPP), a metabolic disorder, leads to the accumulation of protoporphyrin (PPIX). In addition to the most prominent symptom of incapacitating phototoxic skin reactions, 20% of EPP patients exhibit disturbed liver functioning and 4% experience terminal liver failure caused by the hepatobiliary elimination of excess PPIX. Skin symptoms are mitigated through the application of the controlled-release implant afamelanotide, an α-MSH analog, every sixty days. Recently, we showed that liver function tests (LFTs) improved during afamelanotide treatment when compared to before treatment. The present study investigated whether this effect is dose-dependent, as the evidence of dose dependency would support a beneficial influence of afamelanotide. METHODS In this retrospective observational study, we included 2933 liver-function tests, 1186 PPIX concentrations and 1659 afamelanotide implant applications in 70 EPP patients. We investigated whether the number of days since the preceding afamelanotide dose or the number of doses during the preceding 365 days had an effect on LFTs and PPIX levels. In addition, we assessed the effect of global radiation. RESULTS Inter-patient differences exerted the most prominent effect on PPIX and LFTs. In addition, PPIX increased significantly with an increase in the number of days since the last afamelanotide implant (p < 0.0001). ALAT and bilirubin decreased significantly with an increasing number of afamelanotide doses in the preceding 365 days (p = 0.012, p = 0.0299, respectively). Global radiation only influenced PPIX (p = 0.0113). CONCLUSIONS These findings suggest that afamelanotide ameliorates both PPIX concentrations and LFTs in EPP in a dose-dependent manner.
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Affiliation(s)
- Anna-Elisabeth Minder
- Division of Endocrinology, Diabetology, Porphyria and Clinical Nutrition, Stadtspital Zürich, Triemli, 8063 Zurich, Switzerland
- Swiss Reference Centre for Porphyrias, Stadtspital Zürich, Triemli, 8063 Zurich, Switzerland
| | - Xiaoye Schneider-Yin
- Swiss Reference Centre for Porphyrias, Stadtspital Zürich, Triemli, 8063 Zurich, Switzerland
- Institute of Laboratory Medicine, Stadtspital Zürich, Triemli, 8063 Zurich, Switzerland
- Faculty of Medicine, University of Zurich, 8006 Zurich, Switzerland
| | - Henryk Zulewski
- Division of Endocrinology, Diabetology, Porphyria and Clinical Nutrition, Stadtspital Zürich, Triemli, 8063 Zurich, Switzerland
- Department of Biosystems Science and Engineering (D-BSSE), ETH, 8092 Zurich, Switzerland
- Faculty of Medicine, University of Basel, 4001 Basel, Switzerland
| | - Christoph E. Minder
- Department of Social and Preventive Medicine, University of Bern, 3012 Bern, Switzerland
| | - Elisabeth I. Minder
- Division of Endocrinology, Diabetology, Porphyria and Clinical Nutrition, Stadtspital Zürich, Triemli, 8063 Zurich, Switzerland
- Swiss Reference Centre for Porphyrias, Stadtspital Zürich, Triemli, 8063 Zurich, Switzerland
- Faculty of Medicine, University of Zurich, 8006 Zurich, Switzerland
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2
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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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3
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Complex response to physiological and drug-induced hepatic heme demand in monoallelic ALAS1 mice. Mol Genet Metab Rep 2021; 29:100818. [PMID: 34900592 PMCID: PMC8639769 DOI: 10.1016/j.ymgmr.2021.100818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 11/04/2021] [Indexed: 01/11/2023] Open
Abstract
Regulation of 5-aminolevulinate synthase 1 (ALAS1) for nonerythroid heme is critical for respiration, cell signaling mechanisms and steroid/drug metabolism. ALAS1 is induced in some genetic disorders but unlike other genes in the heme pathway, a gene variant of ALAS1 associated with inherited disease has not been reported. BALB/c mice carrying a null ALAS1 allele caused by a βGEO insert were developed and used to determine the consequences of heme demand of a semi gene copy number. Homozygous disruption of ALAS1 (−/−) was lethal for embryo development post day 6.5 but expression in heterozygotes (+/−) was sufficient for the number of offspring and survival. In both wild type (WT +/+) and +/− mice expression of ALAS1 RNA was greatest in liver and harderian gland and much lower in kidney, lung, heart, brain and spleen. The effects of one WT ALAS1 allele in +/− mice on mRNA levels in liver and harderian gland were less marked compared to brain and other organs that were examined. Many other genes were up-regulated by heterozygosity in liver and brain but to a minimal extent. Hepatic heme oxygenase 1 (HMOX1) mRNA expression was significantly lower in +/− mice but not in brain. No elevated translation of WT allele ALAS1 mRNA was detected in +/− liver as a compensatory mechanism for the disabled allele. Fasting induced ALAS1 mRNA in both WT and +/− mice but only in +/− was this manifest as increased ALAS1 protein. The hepatic protoporphyria-inducing drug 4-ethyl-DDC caused induction of hepatic ALAS1 mRNA and protein levels in both WT and +/− mice but markedly less in the mice with only one intact allele. The findings illustrate the complex response of ALAS1 expression for heme demand but limited evidence that upregulation of a wild type allele can compensate for a null allele.
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Key Words
- 4-ethyl-DDC, 4-ethyl-3,5-diethoxycarbonyl-2,6-dimethyl-1,4-dihydropyridine
- AIP, acute intermittent porphyria
- ALAS1, aminolevulinate synthase 1
- Aminolevulinic acid synthase 1
- Compensation, complex regulation
- FECH, ferrochetalase
- HMOX1, heme oxygenase 1
- Hepatic response
- PCR, polymerase chain reaction
- Semi null mice
- WT, wild type
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ABCB6 Polymorphisms are not Overly Represented in Patients with Porphyria. Blood Adv 2021; 6:760-766. [PMID: 34724702 PMCID: PMC8945301 DOI: 10.1182/bloodadvances.2021005484] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 09/14/2021] [Indexed: 11/22/2022] Open
Abstract
ABCB6 is expressed on the cell surface and by multiple organelles, but transport specificity is incompletely understood. In all types of porphyria, ABCB6 polymorphisms are not overrepresented when compared with the overall population.
The Mendelian inheritance pattern of acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria is autosomal dominant, but the clinical phenotype is heterogeneous. Within the general population, penetrance is low, but among first-degree relatives of a symptomatic proband, penetrance is higher. These observations suggest that genetic factors, in addition to mutation of the specific enzyme of the biosynthetic pathway of heme, contribute to the clinical phenotype. Recent studies by others suggested that the genotype of the transporter protein ABCB6 contribute to the porphyria phenotype. Identifying the molecule(s) that are transported by ABCB6 has been problematic and has led to uncertainty with respect to how or if variants/mutants contribute to phenotypic heterogeneity. Knockout mouse models of Abcb6 have not provided a direction for investigation as homozygous knockout animals do not have a discrete phenotype. To address the proposed link between ABC6 genotype and porphyria phenotype, a large cohort of patients with acute hepatic porphyria and erythropoietic protoporphyria was analyzed. Our studies showed that ABCB6 genotype did not correlate with disease severity. Therefore, genotyping of ABCB6 in patients with acute hepatic porphyria and erythropoietic protoporphyria is not warranted.
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Malkiel S, Sayed BA, Ng V, Wall DA, Rozmus J, Schreiber RA, Faytrouni F, Siddiqui I, Chiang KY, Avitzur Y. Sequential paternal haploidentical donor liver and HSCT in EPP allow discontinuation of immunosuppression post-organ transplant. Pediatr Transplant 2021; 25:e14040. [PMID: 34076929 DOI: 10.1111/petr.14040] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2021] [Revised: 04/01/2021] [Accepted: 04/23/2021] [Indexed: 10/21/2022]
Abstract
BACKGROUND EPP is characterized by photosensitivity and by liver disease. When LT is performed in EPP, recurrence often occurs in the allograft due to ongoing protoporphyrin production in bone marrow. Therefore, curative treatment requires allogeneic HSCT after LT. Long-term immunosuppression could be spared by using the same donor for both transplants. METHODS A 2-year-old girl with EPP in liver failure underwent liver transplant from her father. Transfusion and apheresis therapy were used to lower protoporphyrin levels before and after liver transplant. Ten weeks after liver transplant, she underwent HSCT, using the same donor. Conditioning was with treosulfan, fludarabine, cyclophosphamide, and ATG. GVHD prophylaxis was with abatacept, methotrexate, MMF, and tacrolimus. We followed the patient's erythrocyte protoporphyrin and liver and skin health for 2 years after transplant. RESULTS After hematopoietic stem cell engraftment, a decline in protoporphyrin levels was observed, with clinical resolution of photosensitivity. Liver biopsies showed no evidence of EPP. Mild ACR occurred and responded to steroid pulse. Two years post-HSCT, the patient has been weaned off all immunosuppression and remains GVHD and liver rejection free. CONCLUSIONS Sequential liver and HSCT from the same haploidentical donor are feasible in EPP. This strategy can allow for discontinuation of immune suppression.
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Affiliation(s)
- Sarah Malkiel
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON, Canada
| | - Blayne A Sayed
- Division of General and Thoracic Surgery, Hospital for Sick Children Toronto, ON, Canada.,Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Vicky Ng
- Division of Gastroenterology, Hepatology and Nutrition, Department of Paediatrics, Transplant and Regenerative Medicine Centre, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
| | - Donna A Wall
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON, Canada
| | - Jacob Rozmus
- Division of Oncology, Hematology and BMT, Department of Pediatrics, BC Children's Hospital/University of British Columbia, Vancouver, BC, Canada
| | - Richard A Schreiber
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Farah Faytrouni
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Iram Siddiqui
- Department of Pathology, Hospital for Sick Children, Toronto, ON, Canada
| | - Kuang-Yueh Chiang
- Division of Hematology/Oncology, Hospital for Sick Children, Toronto, ON, Canada
| | - Yaron Avitzur
- Division of Gastroenterology, Hepatology and Nutrition, Department of Paediatrics, Transplant and Regenerative Medicine Centre, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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6
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Sardar Pasha SPB, Shetty T, Lambert-Cheatham NA, Sishtla K, Mathew D, Muniyandi A, Patwari N, Bhatwadekar AD, Corson TW. Retinal Phenotyping of Ferrochelatase Mutant Mice Reveals Protoporphyrin Accumulation and Reduced Neovascular Response. Invest Ophthalmol Vis Sci 2021; 62:36. [PMID: 33620374 PMCID: PMC7910629 DOI: 10.1167/iovs.62.2.36] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Purpose Heme depletion, through inhibition of ferrochelatase (FECH), blocks retinal and choroidal neovascularization. Both pharmacologic FECH inhibition and a partial loss-of-function Fech mutation (Fechm1Pas) are associated with decreased neovascularization. However, the ocular physiology of Fechm1Pas mice under basal conditions has not been characterized. Here, we aimed to characterize the retinal phenotype of Fechm1Pas mice. Methods We monitored retinal vasculature at postnatal day 17, 2 months, and 6 months in Fechm1Pas homozygotes, heterozygotes, and their wild-type littermates. We characterized Fech substrate protoporphyrin (PPIX) fluorescence in the eye (excitation = 403 nm, emission = 628 nm), retinal function by electroretinogram, visual acuity by optomotor reflex, and retinal morphology by optical coherence tomography and histology. We stained vasculature using isolectin B4 and fluorescein angiography. We determined endothelial sprouting of retinal and choroidal tissue ex vivo and bioenergetics of retinal punches using a Seahorse flux analyzer. Results Fundi, retinal vasculature, venous width, and arterial tortuosity showed no aberrations. However, VEGF-induced retinal and choroidal sprouting was decreased in Fechm1Pas mutants. Homozygous Fechm1Pas mice had pronounced buildup of PPIX in the posterior eye with no damage to visual function, bioenergetics, and integrity of retinal layers. Conclusions Even with a buildup of PPIX in the retinal vessels in Fechm1Pas homozygotes, the vasculature remains normal. Notably, stimulus-induced ex vivo angiogenesis was decreased in Fechm1Pas mutants, consistent with reduced pathologic angiogenesis seen previously in neovascular animal models. Our findings indicate that Fechm1Pas mice are a useful model for studying the effects of heme deficiency on neovascularization due to Fech blockade.
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Affiliation(s)
- S P B Sardar Pasha
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Trupti Shetty
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States.,Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Nathan A Lambert-Cheatham
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Kamakshi Sishtla
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Deepa Mathew
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Anbukkarasi Muniyandi
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Neeta Patwari
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Ashay D Bhatwadekar
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States.,Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States
| | - Timothy W Corson
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, United States.,Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States.,Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States
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7
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Dynamic changes in murine erythropoiesis from birth to adulthood: implications for the study of murine models of anemia. Blood Adv 2021; 5:16-25. [PMID: 33570621 DOI: 10.1182/bloodadvances.2020003632] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 11/23/2020] [Indexed: 11/20/2022] Open
Abstract
Liver, spleen, and bone marrow are 3 key erythropoietic tissues in mammals. In the mouse, the liver is the predominant site of erythropoiesis during fetal development, the spleen responds to stress erythropoiesis, and the bone marrow is involved in maintaining homeostatic erythropoiesis in adults. However, the dynamic changes and respective contributions of the erythropoietic activity of these tissues from birth to adulthood are incompletely defined. Using C57BL/6 mice, we systematically examined the age-dependent changes in liver, spleen, and bone marrow erythropoiesis following birth. In addition to bone marrow, the liver and spleen of newborn mice sustain an active erythropoietic activity that is gradually lost during first few weeks of life. While the erythropoietic activity of the liver is lost 1 week after birth, that of the spleen is maintained for 7 weeks until the erythropoietic activity of the bone marrow is sufficient to sustain steady-state adult erythropoiesis. Measurement of the red cell parameters demonstrates that these postnatal dynamic changes are reflected by varying indices of circulating red cells. While the red cell numbers, hemoglobin concentration, and hematocrit progressively increase after birth and reach steady-state levels by week 7, reticulocyte counts decrease during this time period. Mean cell volume and mean cell hemoglobin progressively decrease and reach steady state by week 3. Our findings provide comprehensive insights into developmental changes of murine erythropoiesis postnatally and have significant implications for the appropriate interpretation of findings from the variety of murine models used in the study of normal and disordered erythropoiesis.
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8
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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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9
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Barman-Aksözen J, C Wiek P, Bansode VB, Koentgen F, Trüb J, Pelczar P, Cinelli P, Schneider-Yin X, Schümperli D, Minder EI. Modeling the ferrochelatase c.315-48C modifier mutation for erythropoietic protoporphyria (EPP) in mice. Dis Model Mech 2017; 10:225-233. [PMID: 28093505 PMCID: PMC5374324 DOI: 10.1242/dmm.027755] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 12/29/2016] [Indexed: 01/11/2023] Open
Abstract
Erythropoietic protoporphyria (EPP) is caused by deficiency of ferrochelatase (FECH), which incorporates iron into protoporphyrin IX (PPIX) to form heme. Excitation of accumulated PPIX by light generates oxygen radicals that evoke excessive pain and, after longer light exposure, cause ulcerations in exposed skin areas of individuals with EPP. Moreover, ∼5% of the patients develop a liver dysfunction as a result of PPIX accumulation. Most patients (∼97%) have a severe FECH mutation (Mut) in trans to an intronic polymorphism (c.315-48C), which reduces ferrochelatase synthesis by stimulating the use of an aberrant 3′ splice site 63 nt upstream of the normal site for exon 4. In contrast, with the predominant c.315-48T allele, the correct splice site is mostly used, and individuals with a T/Mut genotype do not develop EPP symptoms. Thus, the C allele is a potential target for therapeutic approaches that modify this splicing decision. To provide a model for pre-clinical studies of such approaches, we engineered a mouse containing a partly humanized Fech gene with the c.315-48C polymorphism. F1 hybrids obtained by crossing these mice with another inbred line carrying a severe Fech mutation (named m1Pas) show a very strong EPP phenotype that includes elevated PPIX in the blood, enlargement of liver and spleen, anemia, as well as strong pain reactions and skin lesions after a short period of light exposure. In addition to the expected use of the aberrant splice site, the mice also show a strong skipping of the partly humanized exon 3. This will limit the use of this model for certain applications and illustrates that engineering of a hybrid gene may have unforeseeable consequences on its splicing. Summary: A new mouse model reproduces the predominant genetic disposition of patients affected by erythropoietic protoporphyria, a rare disease associated with extreme pain after light exposure.
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Affiliation(s)
- Jasmin Barman-Aksözen
- Institute of Laboratory Medicine, Municipal Hospital Triemli, Zürich 8063, Switzerland
| | - Paulina C Wiek
- Institute of Cell Biology, University of Bern, Bern 3012, Switzerland
| | - Vijay B Bansode
- Institute of Cell Biology, University of Bern, Bern 3012, Switzerland
| | | | - Judith Trüb
- Institute of Cell Biology, University of Bern, Bern 3012, Switzerland
| | - Pawel Pelczar
- Center for Transgenic Models, University of Basel, Basel 4002, Switzerland
| | - Paolo Cinelli
- Division of Trauma Surgery, University Hospital Zürich, Zürich 8091, Switzerland
| | - Xiaoye Schneider-Yin
- Institute of Laboratory Medicine, Municipal Hospital Triemli, Zürich 8063, Switzerland
| | - Daniel Schümperli
- Institute of Cell Biology, University of Bern, Bern 3012, Switzerland
| | - Elisabeth I Minder
- Institute of Laboratory Medicine, Municipal Hospital Triemli, Zürich 8063, Switzerland .,Porphyria Outpatient Clinics, Municipal Hospital Triemli, Zürich 8063, Switzerland
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10
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Fukuda Y, Cheong PL, Lynch J, Brighton C, Frase S, Kargas V, Rampersaud E, Wang Y, Sankaran VG, Yu B, Ney PA, Weiss MJ, Vogel P, Bond PJ, Ford RC, Trent RJ, Schuetz JD. The severity of hereditary porphyria is modulated by the porphyrin exporter and Lan antigen ABCB6. Nat Commun 2016; 7:12353. [PMID: 27507172 PMCID: PMC4987512 DOI: 10.1038/ncomms12353] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 06/23/2016] [Indexed: 01/10/2023] Open
Abstract
Hereditary porphyrias are caused by mutations in genes that encode haem biosynthetic enzymes with resultant buildup of cytotoxic metabolic porphyrin intermediates. A long-standing open question is why the same causal porphyria mutations exhibit widely variable penetrance and expressivity in different individuals. Here we show that severely affected porphyria patients harbour variant alleles in the ABCB6 gene, also known as Lan, which encodes an ATP-binding cassette (ABC) transporter. Plasma membrane ABCB6 exports a variety of disease-related porphyrins. Functional studies show that most of these ABCB6 variants are expressed poorly and/or have impaired function. Accordingly, homozygous disruption of the Abcb6 gene in mice exacerbates porphyria phenotypes in the Fechm1Pas mouse model, as evidenced by increased porphyrin accumulation, and marked liver injury. Collectively, these studies support ABCB6 role as a genetic modifier of porphyria and suggest that porphyrin-inducing drugs may produce excessive toxicities in individuals with the rare Lan(−) blood type. Accumulation of intermediates of haem biosynthesis, porphyrins, is harmful and usually inherited, but it is unclear how the same mutation may make some individuals more ill than others. Here, the authors show that a porphyrin transporter ABCB6 is a modulator of porphyria, and that patients with functionally defective ABCB6 show more severe symptoms.
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Affiliation(s)
- Yu Fukuda
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Pak Leng Cheong
- Department of Medical Genomics, Royal Prince Alfred Hospital, Sydney, New South Wales 2050, Australia.,Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - John Lynch
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Cheryl Brighton
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Sharon Frase
- Department of Tissue Cell Biology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Vasileios Kargas
- Department of Structural Biology, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Evadnie Rampersaud
- Department of Computational Biology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA.,Department of Hematology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Yao Wang
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Vijay G Sankaran
- Division of Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Bing Yu
- Department of Medical Genomics, Royal Prince Alfred Hospital, Sydney, New South Wales 2050, Australia.,Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Paul A Ney
- New York Blood Center, New York, New York 10065, USA
| | - Mitchell J Weiss
- Department of Hematology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Peter Vogel
- Department of Pathology, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
| | - Peter J Bond
- Bioinformatics Institute, 30 Biopolis Street, Singapore 138671, Singapore.,Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore
| | - Robert C Ford
- Department of Structural Biology, Faculty of Life Sciences, University of Manchester, Manchester M13 9PT, UK
| | - Ronald J Trent
- Department of Medical Genomics, Royal Prince Alfred Hospital, Sydney, New South Wales 2050, Australia.,Sydney Medical School, University of Sydney, Sydney, New South Wales 2006, Australia
| | - John D Schuetz
- Department of Pharmaceutical Sciences, St Jude Children's Research Hospital, Memphis, Tennessee 38105, USA
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11
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Martelli A, Schmucker S, Reutenauer L, Mathieu JRR, Peyssonnaux C, Karim Z, Puy H, Galy B, Hentze MW, Puccio H. Iron regulatory protein 1 sustains mitochondrial iron loading and function in frataxin deficiency. Cell Metab 2015; 21:311-323. [PMID: 25651183 DOI: 10.1016/j.cmet.2015.01.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 12/22/2014] [Accepted: 01/16/2015] [Indexed: 12/22/2022]
Abstract
Mitochondrial iron accumulation is a hallmark of diseases associated with impaired iron-sulfur cluster (Fe-S) biogenesis, such as Friedreich ataxia linked to frataxin (FXN) deficiency. The pathophysiological relevance of the mitochondrial iron loading and the underlying mechanisms are unknown. Using a mouse model of hepatic FXN deficiency in combination with mice deficient for iron regulatory protein 1 (IRP1), a key regulator of cellular iron metabolism, we show that IRP1 activation in conditions of Fe-S deficiency increases the available cytosolic labile iron pool. Surprisingly, our data indicate that IRP1 activation sustains mitochondrial iron supply and function rather than driving detrimental iron overload. Mitochondrial iron accumulation is shown to depend on mitochondrial dysfunction and heme-dependent upregulation of the mitochondrial iron importer mitoferrin-2. Our results uncover an unexpected protective role of IRP1 in pathological conditions associated with altered Fe-S metabolism.
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Affiliation(s)
- Alain Martelli
- Translational Medecine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France; INSERM, U596, 67400 Illkirch, France; CNRS, UMR7104, 67400 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France; Collège de France, Chaire de génétique humaine, 67400 Illkirch, France.
| | - Stéphane Schmucker
- Translational Medecine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France; INSERM, U596, 67400 Illkirch, France; CNRS, UMR7104, 67400 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France; Collège de France, Chaire de génétique humaine, 67400 Illkirch, France
| | - Laurence Reutenauer
- Translational Medecine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France; INSERM, U596, 67400 Illkirch, France; CNRS, UMR7104, 67400 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France; Collège de France, Chaire de génétique humaine, 67400 Illkirch, France
| | - Jacques R R Mathieu
- Institut Cochin, INSERM, U1016, CNRS, UMR8104, Université Paris Descartes, 75014 Paris, France
| | - Carole Peyssonnaux
- Institut Cochin, INSERM, U1016, CNRS, UMR8104, Université Paris Descartes, 75014 Paris, France
| | - Zoubida Karim
- Inserm Unité 1149, Center for Research on Inflammation (CRI), Université Paris Diderot, Sorbonne Paris Cité, site Bichat, 75018 Paris, France
| | - Hervé Puy
- Inserm Unité 1149, Center for Research on Inflammation (CRI), Université Paris Diderot, Sorbonne Paris Cité, site Bichat, 75018 Paris, France; AP-HP, Centre Français des Porphyries, Hôpital Louis Mourier, 92701 Colombes, France
| | - Bruno Galy
- European Molecular Biology Laboratory, 69117 Heidelberg, Germany
| | | | - Hélène Puccio
- Translational Medecine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), 67400 Illkirch, France; INSERM, U596, 67400 Illkirch, France; CNRS, UMR7104, 67400 Illkirch, France; Université de Strasbourg, 67000 Strasbourg, France; Collège de France, Chaire de génétique humaine, 67400 Illkirch, France.
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12
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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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13
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Lyoumi S, Lefebvre T, Karim Z, Gouya L, Puy H. PXR-ALAS1: a key regulatory pathway in liver toxicity induced by isoniazid-rifampicin antituberculosis treatment. Clin Res Hepatol Gastroenterol 2013; 37:439-41. [PMID: 23916555 DOI: 10.1016/j.clinre.2013.06.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Accepted: 06/26/2013] [Indexed: 02/04/2023]
Affiliation(s)
- Said Lyoumi
- Université Versailles-Saint-Quentin-en-Yvelines, Guyancourt, France; Inserm U773, université Paris-Diderot, centre de recherche biomédicale Bichat-Beaujon, site Bichat, Paris, France
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14
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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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15
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Duchartre Y, Petit N, Moya C, Lalanne M, Dubus P, Verneuil HD, Moreau-Gaudry F, Richard E. Neonatal bone marrow transplantation prevents liver disease in a murine model of erythropoietic protoporphyria. J Hepatol 2011; 55:162-70. [PMID: 21145811 DOI: 10.1016/j.jhep.2010.09.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2010] [Revised: 09/02/2010] [Accepted: 09/19/2010] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS Erythropoietic protoporphyria (EPP) is an inherited disorder of heme biosynthesis caused by partial ferrochelatase deficiency, resulting in protoporphyrin IX (PPIX) accumulation in erythrocytes, responsible for skin photosensitivity. In some EPP patients, the development of cholestatic liver injury due to PPIX accumulation can lead to hepatic failure. In adult EPP mice, bone marrow transplantation (BMT) leads to skin photosensitivity correction but fails to reverse liver damages, probably because of the irreversible nature of liver fibrosis. Our aim was to determine the time course of liver disease progression in EPP mice and to evaluate the protective effect of BMT into neonates. METHODS We studied the development of liver disease from birth in EPP mice, in relation with erythroid and hepatic PPIX accumulation. To prevent the development of liver disease, BMT was performed into newborn mice using a novel busulfan-mediated preconditioning assay. RESULTS We showed that hepatic PPIX accumulates during the first 2 weeks and correlates with the onset of a progressive liver fibrosis in 12-day-old EPP mice. Transplantation of normal congenic hematopoietic stem cells into EPP neonates led to long-term donor hematopoiesis recovery. A full correction of erythroid PPIX accumulation and skin photosensitivity was obtained. Furthermore, five months after neonatal BMT, liver damage was almost completely prevented. CONCLUSIONS We demonstrated for the first time that BMT could be successfully used to prevent liver disease in EPP mice and suggested that BMT would be an attractive therapeutic option to prevent severe liver dysfunction in EPP patients.
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Affiliation(s)
- Yann Duchartre
- Univ. de Bordeaux Biothérapies des maladies génétiques et cancers, U1035, F-33000 Bordeaux, France
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16
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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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17
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La protoporphyrie érythropoïétique. Ann Dermatol Venereol 2011; 138:62-4; quiz 61, 65. [DOI: 10.1016/j.annder.2010.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 10/12/2010] [Indexed: 11/21/2022]
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18
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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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19
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Wahlin S, Harper P. Skin Ferrochelatase and Photosensitivity in Mice and Man. J Invest Dermatol 2010; 130:631-3. [DOI: 10.1038/jid.2009.246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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20
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Bone Marrow-Derived Cells Promote Liver Regeneration in Mice With Erythropoietic Protoporphyria. Transplantation 2009; 88:1332-40. [DOI: 10.1097/tp.0b013e3181bce00e] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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21
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Transgenic Leishmania model for delta-aminolevulinate-inducible monospecific uroporphyria: cytolytic phototoxicity initiated by singlet oxygen-mediated inactivation of proteins and its ablation by endosomal mobilization of cytosolic uroporphyrin. EUKARYOTIC CELL 2008; 7:1146-57. [PMID: 18487349 DOI: 10.1128/ec.00365-07] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Inherent deficiencies of Leishmania in heme biosynthesis were genetically complemented for delta-aminolevulinate-inducible biosynthesis and accumulation of light-excitable uroporphyrin. The phototoxic flagellar immobilization and cytolysis phenotypes and porphyrin mobilization noted previously were further analyzed biochemically and cytologically to delineate the mechanism of phototoxicity and detoxification in this monoporphyric model. Under optimal conditions of induction for approximately 3 days, cells remained viable but became increasingly uroporphyric, peaking at > or =90% of the population by approximately day 2; thereafter, a small population of less porphyric or aporphyric cells emerged. On exposure to light, the flagella of porphyric cells were immobilized in milliseconds, and singlet oxygen became detectable in their lysates. Both photosensitive phenotypes increased proportionally with the cellular uroporphyric levels and were susceptible to inhibition by azide, but not by D-mannitol. Brief irradiation of the uroporphyric cells produced no appreciable protein degradation but inactivated cytosolic neomycin phosphotransferase and significantly bleached cytosolic green fluorescent protein, which was azide reversible. These cells were irreparably photodamaged, as indicated by their subsequent loss of membrane permeability and viability. This is the first in situ demonstration that early inactivation of functional proteins by singlet oxygen initiates the cytolytic phototoxicity in uroporphyria. Detoxification appears to involve endocytic/exocytic mobilization of uroporphyrin from cytosol to "porphyrinosomes" for its eventual extracellular expulsion. This is proposed as the sole mechanism of detoxification, since it is attributable to the reversion of porphyric to aporphyric cells during uroporphyrinogenesis and repeated cycles of this event plus photolysis selected no resistant mutants, only aporphyric clones of the parental phenotypes. Further characterization of the transport system for uroporphyrin in this model is expected to benefit not only our understanding of the cellular mechanism for disposal of toxic soluble wastes but also potentially the effective management of human uroporphyria and the use of uroporphyric Leishmania for vaccine/drug delivery.
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22
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Bloomer J, Wang Y, Chen D. Level of Expression of the Nonmutant FerrochelataseAllele is a Determinant of Biochemical Phenotype in a Mouse Model of Erythropoietic Protoporphyria. GENE REGULATION AND SYSTEMS BIOLOGY 2008; 2:233-41. [PMID: 19787086 PMCID: PMC2733089 DOI: 10.4137/grsb.s636] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ferrochelatase (FECH) activity is decreased in erythropoietic protoporphyria (EPP), causing increased production and excretion of protoporphyrin. This study examined whether the level of expression of the nonmutant FECH allele is a determinant of phenotype in a mouse model of EPP that carries a heterozygous deletion of exon 10 in FECH. Two mice strains that had a two-fold difference in FECH mRNA levels in bone marrow and liver (low expressing C3H/HeJ and high expressing CBA/J) were used to establish congenic strains containing the mutation. Erythrocyte protoporphyrin levels in C3H/HeJ heterozygous mice were significantly higher than in their wildtype littermates, whereas levels in CBA/J heterozygous mice did not differ significantly from their wildtype littermates. Biliary excretion of protoporphyrin was also significantly higher in C3H/HeJ heterozygous mice. The levels of normal FECH mRNA in bone marrow measured by real time PCR were 138 +/− 30 copies per ug total RNA in C3H/HeJ +/− mice, 320 +/− 59 in C3H/HeJ +/+ mice and 634 +/− 38 in CBA/J +/+ mice. Levels in liver tissue of the mice differed significantly in the same pattern. Thus, the level of expression of the nonmutant FECH allele is a determinant of phenotype in a mouse model of EPP as has been demonstrated in human EPP.
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Affiliation(s)
| | | | - Dongquan Chen
- Division of Hematology/Oncology Department of Medicine, University of Alabama at Birmingham School of Medicine, Birmingham, Alabama
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23
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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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24
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Lyoumi S, Abitbol M, Andrieu V, Henin D, Robert E, Schmitt C, Gouya L, de Verneuil H, Deybach JC, Montagutelli X, Beaumont C, Puy H. Increased plasma transferrin, altered body iron distribution, and microcytic hypochromic anemia in ferrochelatase-deficient mice. Blood 2006; 109:811-8. [PMID: 17003376 DOI: 10.1182/blood-2006-04-014142] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractPatients with deficiency in ferrochelatase (FECH), the last enzyme of the heme biosynthetic pathway, experience a painful type of skin photosensitivity called erythropoietic protoporphyria (EPP), which is caused by the excessive production of protoporphyrin IX (PPIX) by erythrocytes. Controversial results have been reported regarding hematologic status and iron status of patients with EPP. We thoroughly explored these parameters in Fechm1Pas mutant mice of 3 different genetic backgrounds. FECH deficiency induced microcytic hypochromic anemia without ringed sideroblasts, little or no hemolysis, and no erythroid hyperplasia. Serum iron, ferritin, hepcidin mRNA, and Dcytb levels were normal. The homozygous Fechm1Pas mutant involved no tissue iron deficiency but showed a clear-cut redistribution of iron stores from peripheral tissues to the spleen, with a concomitant 2- to 3-fold increase in transferrin expression at the mRNA and the protein levels. Erythrocyte PPIX levels strongly correlated with serum transferrin levels. At all stages of differentiation in our study, transferrin receptor expression in bone marrow erythroid cells in Fechm1Pas was normal in mutant mice but not in patients with iron-deficiency anemia. Based on these observations, we suggest that oral iron therapy is not the therapy of choice for patients with EPP and that the PPIX–liver transferrin pathway plays a role in the orchestration of iron distribution between peripheral iron stores, the spleen, and the bone marrow.
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