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Kawamura S, Otani M, Miyamoto T, Abe J, Ihara R, Inawaka K, Fantel AG. Different effects of an N-phenylimide herbicide on heme biosynthesis between human and rat erythroid cells. Reprod Toxicol 2021; 99:27-38. [PMID: 33249232 DOI: 10.1016/j.reprotox.2020.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/28/2020] [Accepted: 11/22/2020] [Indexed: 01/10/2023]
Abstract
Rat developmental toxicity including embryolethality and teratogenicity (mainly ventricular septal defects and wavy ribs) were produced by S-53482, an N-phenylimide herbicide that inhibits protoporphyrinogen oxidase (PPO) common to chlorophyll and heme biosynthesis. The sequence of key biological events in the mode of action has been elucidated as follows: inhibition of PPO interferes with normal heme synthesis, which causes loss of blood cells leading to fetal anemia, embryolethality and the development of malformations. In this study we investigated whether the rat is a relevant model for the assessment of the human hazard of the herbicide. To study effects on heme biosynthesis, human erythroleukemia, human cord blood, and rat erythroleukemia cells were treated with the herbicide during red cell differentiation. Protoporphyrin IX, a marker of PPO inhibition, and heme were determined. We investigated whether synchronous maturation of primitive erythropoiesis, which can contribute to massive losses of embryonic blood, occurs in rats. The population of primitive erythroblasts was observed on gestational days 11 through 14. Heme production was suppressed in rat erythroid cells. In contrast, heme reduction was not seen in both human erythroid cells when PPO was inhibited. Rats underwent synchronous maturation in primitive erythropoiesis. Our results combined with epidemiological findings that patients with deficient PPO are not anemic led us to conclude that human erythroblasts are resistant to the herbicide. It is suggested that the rat would be an inappropriate model for assessing the developmental toxicity of S-53482 in humans as rats are specifically sensitive to PPO inhibition by the herbicide.
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Affiliation(s)
- Satoshi Kawamura
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 1-98, Kasugade-naka 3-chome, Konohana-ku, Osaka, 554-8558, Japan.
| | - Mitsuhiro Otani
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 1-98, Kasugade-naka 3-chome, Konohana-ku, Osaka, 554-8558, Japan
| | - Taiki Miyamoto
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 1-98, Kasugade-naka 3-chome, Konohana-ku, Osaka, 554-8558, Japan
| | - Jun Abe
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 1-98, Kasugade-naka 3-chome, Konohana-ku, Osaka, 554-8558, Japan
| | - Ryo Ihara
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 1-98, Kasugade-naka 3-chome, Konohana-ku, Osaka, 554-8558, Japan
| | - Kunifumi Inawaka
- Environmental Health Science Laboratory, Sumitomo Chemical Co., Ltd., 1-98, Kasugade-naka 3-chome, Konohana-ku, Osaka, 554-8558, Japan
| | - Alan G Fantel
- Department of Pediatrics, University of Washington, 1959 NE Pacific St. Box 366320, Seattle, WA 98195-6320, USA
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Minder AE, Barman-Aksoezen J, Schmid M, Minder EI, Zulewski H, Minder CE, Schneider-Yin X. Beyond pigmentation: signs of liver protection during afamelanotide treatment in Swiss patients with erythropoietic protoporphyria, an observational study. THERAPEUTIC ADVANCES IN RARE DISEASE 2021; 2:26330040211065453. [PMID: 37181106 PMCID: PMC10032460 DOI: 10.1177/26330040211065453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 11/18/2021] [Indexed: 05/16/2023]
Abstract
Erythropoietic protoporphyria (EPP) is an ultra-rare inherited disorder with overproduction of protoporphyrin in maturating erythroblasts. This excess protoporphyrin leads to incapacitating phototoxic burns in sunlight exposed skin. Its biliary elimination causes cholestatic liver injury in 20% and terminal liver failure in 4% of EPP patients. Thereby, the risk of liver injury increases with increasing erythrocyte protoporphyrin concentrations. Afamelanotide, an α-melanocyte-stimulating hormone (MSH) analog inducing skin pigmentation, was shown to improve sunlight tolerance in EPP. Beyond this well-known effect on pigmentation, the MSHs have liver-protective effects and improve survival of maturating erythroblasts, effects described in animal or in vitro models to date only. We investigated whether afamelanotide treatment in EPP has effects on erythropoiesis, protoporphyrin concentrations, and liver injury by analyzing retrospectively our long-term safety data. Methods From the 47 Swiss EPP-patients treated at our center since 2006, we included those 38 patients in the current analysis who received at least one afamelanotide dose between 2016 and 2018 and underwent regular laboratory testing before and during the treatment. We compared the means of pretreatment measurements with those during the treatment. Results Protoporphyrin concentrations dropped from 21.39 ± 11.12 (mean ± SD) before afamelanotide to 16.83 ± 8.24 µmol/L (p < .0001) during treatment. Aspartate aminotransferase decreased from 26.67 ± 13.16 to 22.9 ± 7.76 IU/L (p = .0146). For both entities, patients with higher values showed a more progressive decrease, indicating a risk reduction of EPP-related liver disease. The pre-existing hypochromia and broad mean red-cell distribution width were further augmented under afamelanotide. This was more likely due to an influence of afamelanotide on maturating erythroblasts than due to an exacerbated iron deficiency, as mean zinc-protoporphyrin decreased significantly and ferritin remained unchanged. No serious afamelanotide-related adverse events were observed for a total of 240 treatment years. Conclusion Our findings point to a protective effect of afamelanotide on erythroblast maturation and protoporphyrin-induced liver injury. Plain Language summary Afamelanotide, a skin tanning hormone, may protect patients with erythropoietic protoporphyria not only from skin burns, but also from liver injury associated with the disease. Patients with erythropoietic protoporphyria (EPP), an inherited metabolic disease, suffer from light-induced skin burns and liver injury elicited by the accumulated light sensitizer protoporphyrin. The excess protoporphyrin is produced in red cell precursors in the bone marrow, and it is eliminated from the body via the liver and bile. A high protoporphyrin excretion burden damages the liver cells, the risk for this increases with higher protoporphyrin concentrations. About 20% of EPP patients show some sign of liver injury and 4% develop life-threatening liver dysfunction.Afamelanotide, closely related to natural α-melanocyte stimulating hormone (MSH), induces skin tanning. This effect protects EPP patients from light-induced skin burns as shown in previous studies. We have treated Swiss EPP patients with afamelanotide since 2006, and we regularly perform safety tests of this treatment.Recent in vitro and animal studies demonstrated α-MSH effects other than skin tanning, including an improved synthesis of red blood cell precursors in the bone-marrow and protection of the liver from experimentally induced damage. Until now, it is unknown whether afamelanotide has similar effects in the human organism.To study this question, we analyzed retrospectively the safety laboratory data of 38 Swiss patients, who received at least one dose of afamelanotide from 2016 to 2019. We found that both, the average protoporphyrin concentrations and aspartate aminotransferase, a test for liver function, improved during afamelanotide treatment as compared to before.We concluded that afamelanotide applied to EPP patients to protect them from light-induced skin burns also may reduce their risk of liver injury.
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Affiliation(s)
- Anna-Elisabeth Minder
- Division of Endocrinology, Diabetology,
Porphyria, Stadtspital Zürich, Birmensdorferstrasse 497, 8063 Zurich,
Switzerland
| | | | - Mathias Schmid
- Department of Hematology and Oncology,
Stadtspital Zürich, Zurich, Switzerland
| | - Elisabeth I. Minder
- Division of Endocrinology, Diabetology,
Porphyria, Stadtspital Zürich, Zurich, Switzerland
| | - Henryk Zulewski
- Division of Endocrinology, Diabetology,
Porphyria, Stadtspital Zürich, Zurich, Switzerland
| | - Christoph E. Minder
- Department of Social and Preventive Medicine,
University of Bern, Bern, Switzerland
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53
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Lahiji AP, Anderson KE, Chan A, Simon A, Desnick RJ, Ramanujam VMS. 5-Aminolevulinate dehydratase porphyria: Update on hepatic 5-aminolevulinic acid synthase induction and long-term response to hemin. Mol Genet Metab 2020; 131:418-423. [PMID: 33199206 DOI: 10.1016/j.ymgme.2020.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/21/2020] [Accepted: 10/23/2020] [Indexed: 11/17/2022]
Abstract
BACKGROUND 5-Aminolevulinic acid dehydratase (ALAD) porphyria (ADP) is an ultrarare autosomal recessive disease, with only eight documented cases, all of whom were males. Although classified as an acute hepatic porphyria (AHP), induction of the rate limiting hepatic enzyme 5-aminolevulinic acid synthase-1 (ALAS1) has not been demonstrated, and the marrow may also contribute excess 5-aminolevulinic acid (ALA). Two patients have died and reported follow up for the others is limited, so the natural history of this disease is poorly understood and treatment experience limited. METHODS We report new molecular findings and update the clinical course and treatment of the sixth reported ADP patient, now 31 years old and the only known case in the Americas, and review published data regarding genotype-phenotype correlation and treatment. RESULTS Circulating hepatic 5-aminolevulinic acid synthase-1 (ALAS1) mRNA was elevated in this case, as in other AHPs. Gain of function mutation of erythroid specific ALAS2 - an X-linked modifying gene in some other porphyrias - was not found. Seven reported ADP cases had compound heterozygous ALAD mutations resulting in very low residual ALAD activity and symptoms early in life or adolescence. One adult with a germline ALAD mutant allele developed ADP in association with a clonal myeloproliferative disorder, polycythemia vera. CONCLUSIONS Elevation in circulating hepatic ALAS1 and response to treatment with hemin indicate that the liver is an important source of excess ALA in ADP, although the marrow may also contribute. Intravenous hemin was effective in most reported cases for treatment and prevention of acute attacks of neurological symptoms.
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MESH Headings
- 5-Aminolevulinate Synthetase/blood
- 5-Aminolevulinate Synthetase/genetics
- Adolescent
- Adult
- Child
- Child, Preschool
- Female
- Heme/genetics
- Hemin/administration & dosage
- Humans
- Infant
- Infant, Newborn
- Liver/metabolism
- Liver/pathology
- Male
- Middle Aged
- Mutation/genetics
- Porphobilinogen/metabolism
- Porphobilinogen Synthase/blood
- Porphobilinogen Synthase/deficiency
- Porphobilinogen Synthase/genetics
- Porphyria, Acute Intermittent/blood
- Porphyria, Acute Intermittent/drug therapy
- Porphyria, Acute Intermittent/genetics
- Porphyria, Acute Intermittent/pathology
- Porphyrias, Hepatic/blood
- Porphyrias, Hepatic/drug therapy
- Porphyrias, Hepatic/genetics
- Porphyrias, Hepatic/pathology
- RNA, Messenger/blood
- Young Adult
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Affiliation(s)
- Arian Pourmehdi Lahiji
- Departments of Preventive Medicine and Population Health, and Internal Medicine (Division of Gastroenterology and Hepatology), University of Texas Medical Branch, Galveston, Texas, USA
| | - Karl E Anderson
- Departments of Preventive Medicine and Population Health, and Internal Medicine (Division of Gastroenterology and Hepatology), University of Texas Medical Branch, Galveston, Texas, USA.
| | - Amy Chan
- Alnylam Pharmaceuticals, Cambridge, MA, USA
| | - Amy Simon
- Alnylam Pharmaceuticals, Cambridge, MA, USA
| | - Robert J Desnick
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - V M Sadagopa Ramanujam
- Departments of Preventive Medicine and Population Health, and Internal Medicine (Division of Gastroenterology and Hepatology), University of Texas Medical Branch, Galveston, Texas, USA
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54
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Barman-Aksözen J, Nydegger M, Schneider-Yin X, Minder AE. Increased phototoxic burn tolerance time and quality of life in patients with erythropoietic protoporphyria treated with afamelanotide - a three years observational study. Orphanet J Rare Dis 2020; 15:213. [PMID: 32811524 PMCID: PMC7437008 DOI: 10.1186/s13023-020-01505-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 08/09/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Erythropoietic protoporphyria (EPP) is an ultra-rare genetic disorder (prevalence 1:150`000) characterized by instant painful phototoxic burn reactions in skin exposed to visible light. Afamelanotide is the first clinically tested therapy effectively increasing the time EPP patients can spend in direct sunlight without developing symptoms and reducing the number and severity of phototoxic reactions. OBJECTIVES We report our data on real-world effectiveness of afamelanotide treatment in EPP and its phototoxic burn protection factor (PBPF). METHODS We analysed clinical data collected between 2016 and 2018 in the Swiss EPP cohort (n = 39) on maximum phototoxic burn tolerance time (PBTT), i.e., maximum time spent in sunlight without phototoxic reaction, severity of phototoxic reactions as assessed by an 11-point Likert-type visual analogue scale (VAS), with 0 being no pain and 10 being the worst possible pain, and Quality of Life (QoL), as assessed with an EPP-specific instrument. RESULTS Before treatment, the PBTT was median 10 min (IQR 5-20). Under treatment, PBTT increased to median 180 min (IQR 120-240). Individual PBPF increased 1.8- to 180-fold (full range, median 15). The pain severity of the worst phototoxic reaction before treatment was median 10 and under treatment median 6 (IQR 3-7). QoL at the end of the observation period in 2018 (with all the assessed patients under treatment) was 81.4% (IQR 69.4-93.4, n = 34). A 97.4% treatment adherence rate was observed. CONCLUSION Treatment of EPP patients with afamelanotide is highly effective under real-world conditions. We suggest PBTT as a clinical meaningful endpoint in further clinical trials.
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Affiliation(s)
| | - Michèle Nydegger
- Institute of Anesthesia and Intensive Medicine, Stadtspital Waid und Triemli, Zurich, Switzerland
| | - Xiaoye Schneider-Yin
- Institute of Laboratory Medicine, Stadtspital Waid und Triemli, Zurich, Switzerland
| | - Anna-Elisabeth Minder
- Department for Endocrinology, Diabetology, Porphyria, Stadtspital Waid und Triemli, Zurich, Switzerland.
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55
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Bailey HJ, Bezerra GA, Marcero JR, Padhi S, Foster WR, Rembeza E, Roy A, Bishop DF, Desnick RJ, Bulusu G, Dailey HA, Yue WW. Human aminolevulinate synthase structure reveals a eukaryotic-specific autoinhibitory loop regulating substrate binding and product release. Nat Commun 2020; 11:2813. [PMID: 32499479 PMCID: PMC7272653 DOI: 10.1038/s41467-020-16586-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2019] [Accepted: 05/11/2020] [Indexed: 12/12/2022] Open
Abstract
5'-aminolevulinate synthase (ALAS) catalyzes the first step in heme biosynthesis, generating 5'-aminolevulinate from glycine and succinyl-CoA. Inherited frameshift indel mutations of human erythroid-specific isozyme ALAS2, within a C-terminal (Ct) extension of its catalytic core that is only present in higher eukaryotes, lead to gain-of-function X-linked protoporphyria (XLP). Here, we report the human ALAS2 crystal structure, revealing that its Ct-extension folds onto the catalytic core, sits atop the active site, and precludes binding of substrate succinyl-CoA. The Ct-extension is therefore an autoinhibitory element that must re-orient during catalysis, as supported by molecular dynamics simulations. Our data explain how Ct deletions in XLP alleviate autoinhibition and increase enzyme activity. Crystallography-based fragment screening reveals a binding hotspot around the Ct-extension, where fragments interfere with the Ct conformational dynamics and inhibit ALAS2 activity. These fragments represent a starting point to develop ALAS2 inhibitors as substrate reduction therapy for porphyria disorders that accumulate toxic heme intermediates.
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Affiliation(s)
- Henry J Bailey
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK
| | - Gustavo A Bezerra
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK
| | - Jason R Marcero
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Siladitya Padhi
- TCS Innovation Labs-Hyderabad (Life Sciences Division), Tata Consultancy Services Ltd, Hyderabad, 500081, India
| | - William R Foster
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK
| | - Elzbieta Rembeza
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK
| | - Arijit Roy
- TCS Innovation Labs-Hyderabad (Life Sciences Division), Tata Consultancy Services Ltd, Hyderabad, 500081, India
| | - David F Bishop
- Department of Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Robert J Desnick
- Department of Genetics and Genomics Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Gopalakrishnan Bulusu
- TCS Innovation Labs-Hyderabad (Life Sciences Division), Tata Consultancy Services Ltd, Hyderabad, 500081, India
| | - Harry A Dailey
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, 30602, USA
| | - Wyatt W Yue
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Oxford, OX3 7DQ, UK.
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56
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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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57
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Wang T, Wang Y, Dong Q, Xu C, Zhou X, Ouyang Y, Liu Y, Lee JJ, Hu N, Wang K, Zdravkovic TP, Shen J, Nie G, Lian CG, Liu Y. X-linked dominant protoporphyria in a Chinese pedigree reveals a four-based deletion of ALAS2. ANNALS OF TRANSLATIONAL MEDICINE 2020; 8:344. [PMID: 32355788 PMCID: PMC7186625 DOI: 10.21037/atm.2020.02.80] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Background X-linked dominant protoporphyria (XLDPP) is a rare, hereditary disorder that leads to hepatobiliary and hematologic abnormalities including increased erythrocyte protoporphyrin, cutaneous photosensitivity, and decreased iron stores that is caused by a pathogenic mutation of ALAS2 gene. Methods This study aimed to confirm the existence of XLDPP in a Chinese pedigree. We observed and described the dermatoscopic findings of this disorder under dermoscopy, and assessed photo damage in XLDPP patients using the Fotofinder system and very high frequency (VHF) skin ultrasonic system. We performed next generation sequencing and Sanger sequencing to detect and confirm genetic variants in DNA samples from the XLDPP family. Moreover, we monitored the hepatobiliary function as well as hematologic changes in related family members. Results As compared to unaffected control subjects, patients exhibited evidence of severe cutaneous photodamage, causing photoaging, an increase in the size of the gallbladder, increased levels of protoporphyrin in red blood cells, an increase in blood levels of uroporphyrin and hematoporphyrin, and iron deficiency. Conclusions XLDPP was validated by the identification of a four-base-pair deletion (c.1706_1709delAGTG, p.E569fs) in ALAS2 (NM_000032.4) in the proband which segregated with the disease in an X-linked dominant pattern, with hemizygous males being more severely affected than heterozygous females. We also found a missense variant in GATA Binding Protein 1 (GATA1).
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Affiliation(s)
- Tao Wang
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yongwei Wang
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
| | - Qi Dong
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Chenchen Xu
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Xiping Zhou
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yunshu Ouyang
- Department of Ultrasound Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yaping Liu
- Department of Medical Genetics and National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100005, China
| | - Jonathan J Lee
- Program in Dermatopathology, Department of Pathology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA.,Department of Dermatology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Nina Hu
- Program in Dermatopathology, Department of Pathology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Kevin Wang
- Program in Dermatopathology, Department of Pathology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA.,SUNY Upstate Medical University, Syracuse, NY, USA
| | - Tanja Prunk Zdravkovic
- Dermatovenerology Department, Celje General and Teaching Hospital, Oblakova 5, 3000 Celje, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Jun Shen
- Department of Pathology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.,Laboratory for Molecular Medicine, Partners Personalized Medicine, Cambridge, MA, USA
| | - Guangjun Nie
- CAS Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, CAS Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
| | - Christine G Lian
- Program in Dermatopathology, Department of Pathology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA, USA
| | - Yuehua Liu
- Department of Dermatology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
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58
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Swenson SA, Moore CM, Marcero JR, Medlock AE, Reddi AR, Khalimonchuk O. From Synthesis to Utilization: The Ins and Outs of Mitochondrial Heme. Cells 2020; 9:E579. [PMID: 32121449 PMCID: PMC7140478 DOI: 10.3390/cells9030579] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Revised: 02/19/2020] [Accepted: 02/23/2020] [Indexed: 12/14/2022] Open
Abstract
Heme is a ubiquitous and essential iron containing metallo-organic cofactor required for virtually all aerobic life. Heme synthesis is initiated and completed in mitochondria, followed by certain covalent modifications and/or its delivery to apo-hemoproteins residing throughout the cell. While the biochemical aspects of heme biosynthetic reactions are well understood, the trafficking of newly synthesized heme-a highly reactive and inherently toxic compound-and its subsequent delivery to target proteins remain far from clear. In this review, we summarize current knowledge about heme biosynthesis and trafficking within and outside of the mitochondria.
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Affiliation(s)
| | - Courtney M. Moore
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA;
| | - Jason R. Marcero
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA;
| | - Amy E. Medlock
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA;
- Augusta University/University of Georgia Medical Partnership, Athens, GA 30602, USA
| | - Amit R. Reddi
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA 30332, USA;
- Parker Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, Atlanta, GA 30332, USA
| | - Oleh Khalimonchuk
- Department of Biochemistry, University of Nebraska, Lincoln, NE 68588, USA;
- Nebraska Redox Biology Center, University of Nebraska, Lincoln, NE 68588, USA
- Fred and Pamela Buffett Cancer Center, Omaha, NE 68105, USA
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59
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Stojanovski BM, Hunter GA, Na I, Uversky VN, Jiang RHY, Ferreira GC. 5-Aminolevulinate synthase catalysis: The catcher in heme biosynthesis. Mol Genet Metab 2019; 128:178-189. [PMID: 31345668 PMCID: PMC6908770 DOI: 10.1016/j.ymgme.2019.06.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/27/2019] [Accepted: 06/07/2019] [Indexed: 01/26/2023]
Abstract
5-Aminolevulinate (ALA) synthase (ALAS), a homodimeric pyridoxal-5'-phosphate (PLP)-dependent enzyme, catalyzes the first step of heme biosynthesis in metazoa, fungi and α-proteobacteria. In this review, we focus on the advances made in unraveling the mechanism of the ALAS-catalyzed reaction during the past decade. The interplay between the PLP cofactor and the protein moiety determines and modulates the multi-intermediate reaction cycle of ALAS, which involves the decarboxylative condensation of two substrates, glycine and succinyl-CoA. Substrate binding and catalysis are rapid, and product (ALA) release dominates the overall ALAS kinetic mechanism. Interconversion between a catalytically incompetent, open conformation and a catalytically competent, closed conformation is linked to ALAS catalysis. Reversion to the open conformation, coincident with ALA dissociation, defines the slowest step of the reaction cycle. These findings were further substantiated by introducing seven mutations in the16-amino acid loop that gates the active site, yielding an ALAS variant with a greatly increased rate of catalytic turnover and heightened specificity constants for both substrates. Recently, molecular dynamics (MD) simulation analysis of various dimeric ALAS forms revealed that the seven active site loop mutations caused the proteins to adopt different conformations. In particular, the emergence of a β-strand in the mutated loop, which interacted with two preexisting β-strands to form an anti-parallel three-stranded β-sheet, conferred the murine heptavariant with a more stable open conformation and prompted faster product release than wild-type mALAS2. Moreover, the dynamics of the mALAS2 active site loop anti-correlated with that of the 35 amino acid C-terminal sequence. This led us to propose that this C-terminal extension, which is absent in prokaryotic ALASs, finely tunes mammalian ALAS activity. Based on the above results, we extend our previous proposal to include that discovery of a ligand inducing the mammalian C-terminal extension to fold offers a good prospect for the development of a new drug for X-linked protoporphyria and/or other porphyrias associated with enhanced ALAS activity and/or porphyrin accumulation.
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Affiliation(s)
- Bosko M Stojanovski
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Gregory A Hunter
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA
| | - Insung Na
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA.
| | - Vladimir N Uversky
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Institute for Biological Instrumentation of the Russian Academy of Sciences, Pushchino, Moscow region 142290, Russia
| | - Rays H Y Jiang
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Gloria C Ferreira
- Department of Molecular Medicine, Morsani College of Medicine, University of South Florida, Tampa, FL 33612, USA; Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA; Department of Chemistry, College of Arts and Sciences, University of South Florida, Tampa, FL 33612, USA.
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60
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Barman-Aksözen J, Halloy F, Iyer PS, Schümperli D, Minder AE, Hall J, Minder EI, Schneider-Yin X. Delta-aminolevulinic acid synthase 2 expression in combination with iron as modifiers of disease severity in erythropoietic protoporphyria. Mol Genet Metab 2019; 128:304-308. [PMID: 31076252 DOI: 10.1016/j.ymgme.2019.04.013] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 04/30/2019] [Accepted: 04/30/2019] [Indexed: 11/30/2022]
Abstract
Deficiency in ferrochelatase (FECH), the last enzyme in the heme biosynthetic pathway, leads to an accumulation of protoporphyrin IX (PPIX) that causes a severely painful phototoxic reaction of the skin in patients with erythropoietic protoporphyria (EPP). Besides phototoxicity of the skin, EPP patients often present with symptoms of iron deficiency in form of a microcytic and hypochromic anemia with low serum iron and ferritin. In addition, elevated aminolevulinic acid synthase 2 (ALAS2) both at the mRNA and protein levels have been observed among EPP patients. ALAS is the first enzyme in the pathway and exists in two isoforms, whereby the isoform 2 (ALAS2) is expressed exclusively in erythropoiesis. The mRNA of ALAS2 contains an iron response element (IRE) at its 5'UTR. When iron is limited, iron response element binding protein 2 (IRP2) binds to the IRE of ALAS2 mRNA and suppresses its translation. In this study, we demonstrated that iron deprivation increased the amount of ALAS2 mRNA as well as the ratio of ALAS2 to FECH mRNAs in cultured erythroleukemic K562 cells. At the protein level, however, iron deprivation in the cell line caused reductions in both enzymes as shown by the Western blot analysis. A comparable increase in the ratio of ALAS2 to FECH mRNAs was also found in EPP patients indicating an imbalance in heme biosynthesis. As iron cannot be completely missing from an organism, we assume that in EPP patients, a certain amount of ALAS2 mRNA is translated despite a partial deficiency of FECH. The increase in ALAS2 enzyme contributes to the accumulation in PPIX in the patients. Targeted inhibition of ALAS2 could therefore be a treatment option for EPP.
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Affiliation(s)
| | - Francois Halloy
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, The Federal Institute of Technology (ETH), Zürich, Switzerland
| | - Pavithra S Iyer
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, The Federal Institute of Technology (ETH), Zürich, Switzerland
| | - Daniel Schümperli
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, The Federal Institute of Technology (ETH), Zürich, Switzerland
| | - Anna Elisabeth Minder
- Division of Endocrinology, Department of Internal Medicine, Municipal Hospital Triemli, Zurich, Switzerland
| | - Jonathan Hall
- Institute of Pharmaceutical Sciences, Department of Chemistry and Applied Biosciences, The Federal Institute of Technology (ETH), Zürich, Switzerland
| | - Elisabeth I Minder
- Division of Endocrinology, Department of Internal Medicine, Municipal Hospital Triemli, Zurich, Switzerland
| | - Xiaoye Schneider-Yin
- Institute of Laboratory Medicine, Municipal Hospital Triemli, Zürich, Switzerland.
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Phillips JD. Heme biosynthesis and the porphyrias. Mol Genet Metab 2019; 128:164-177. [PMID: 31326287 PMCID: PMC7252266 DOI: 10.1016/j.ymgme.2019.04.008] [Citation(s) in RCA: 111] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 04/10/2019] [Accepted: 04/18/2019] [Indexed: 01/08/2023]
Abstract
Porphyrias, is a general term for a group of metabolic diseases that are genetic in nature. In each specific porphyria the activity of specific enzymes in the heme biosynthetic pathway is defective and leads to accumulation of pathway intermediates. Phenotypically, each disease leads to either neurologic and/or photocutaneous symptoms based on the metabolic intermediate that accumulates. In each porphyria the distinct patterns of these substances in plasma, erythrocytes, urine and feces are the basis for diagnostically defining the metabolic defect underlying the clinical observations. Porphyrias may also be classified as either erythropoietic or hepatic, depending on the principal site of accumulation of pathway intermediates. The erythropoietic porphyrias are congenital erythropoietic porphyria (CEP), and erythropoietic protoporphyria (EPP). The acute hepatic porphyrias include ALA dehydratase deficiency porphyria, acute intermittent porphyria (AIP), hereditary coproporphyria (HCP) and variegate porphyria (VP). Porphyria cutanea tarda (PCT) is the only porphyria that has both genetic and/or environmental factors that lead to reduced activity of uroporphyrinogen decarboxylase in the liver. Each of the 8 enzymes in the heme biosynthetic pathway have been associated with a specific porphyria (Table 1). Mutations affecting the erythroid form of ALA synthase (ALAS2) are most commonly associated with X-linked sideroblastic anemia, however, gain-of-function mutations of ALAS2 have also been associated with a variant form of EPP. This overview does not describe the full clinical spectrum of the porphyrias, but is meant to be an overview of the biochemical steps that are required to make heme in both erythroid and non-erythroid cells.
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Affiliation(s)
- John D Phillips
- Division of Hematology, Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT, United States of America.
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Yasuda M, Chen B, Desnick RJ. Recent advances on porphyria genetics: Inheritance, penetrance & molecular heterogeneity, including new modifying/causative genes. Mol Genet Metab 2019; 128:320-331. [PMID: 30594473 PMCID: PMC6542720 DOI: 10.1016/j.ymgme.2018.11.012] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2018] [Revised: 11/26/2018] [Accepted: 11/26/2018] [Indexed: 12/16/2022]
Abstract
The inborn errors of heme biosynthesis, the Porphyrias, include eight major disorders resulting from loss-of-function (LOF) or gain-of-function (GOF) mutations in eight of the nine heme biosynthetic genes. The major sites of heme biosynthesis are the liver and erythron, and the underlying pathophysiology of each of these disorders depends on the unique biochemistry, cell biology, and genetic mechanisms in these tissues. The porphyrias are classified into three major categories: 1) the acute hepatic porphyrias (AHPs), including Acute Intermittent Porphyria (AIP), Hereditary Coproporphyria (HCP), Variegate Porphyria (VP), and 5-Aminolevlulinic Acid Dehydratase Deficient Porphyria (ADP); 2) a hepatic cutaneous porphyria, Porphyria Cutanea Tarda (PCT); and 3) the cutaneous erythropoietic porphyrias, Congenital Erythropoietic Porphyria (CEP), Erythropoietic Protoporphyria (EPP), and X-Linked Protoporphyria (XLP). Their modes of inheritance include autosomal dominant with markedly decreased penetrance (AIP, VP, and HCP), autosomal recessive (ADP, CEP, and EPP), or X-linked (XLP), as well as an acquired sporadic form (PCT). There are severe homozygous dominant forms of the three AHPs. For each porphyria, its phenotype, inheritance pattern, unique genetic principles, and molecular genetic heterogeneity are presented. To date, >1000 mutations in the heme biosynthetic genes causing their respective porphyrias have been reported, including low expression alleles and genotype/phenotype correlations that predict severity for certain porphyrias. The tissue-specific regulation of heme biosynthesis and the unique genetic mechanisms for each porphyria are highlighted.
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Affiliation(s)
- Makiko Yasuda
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Brenden Chen
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
| | - Robert J Desnick
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, United States.
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63
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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: 53] [Impact Index Per Article: 10.6] [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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Peoc'h K, Nicolas G, Schmitt C, Mirmiran A, Daher R, Lefebvre T, Gouya L, Karim Z, Puy H. Regulation and tissue-specific expression of δ-aminolevulinic acid synthases in non-syndromic sideroblastic anemias and porphyrias. Mol Genet Metab 2019; 128:190-197. [PMID: 30737140 DOI: 10.1016/j.ymgme.2019.01.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 01/21/2019] [Accepted: 01/21/2019] [Indexed: 02/07/2023]
Abstract
Recently, new genes and molecular mechanisms have been identified in patients with porphyrias and sideroblastic anemias (SA). They all modulate either directly or indirectly the δ-aminolevulinic acid synthase (ALAS) activity. ALAS, is encoded by two genes: the erythroid-specific (ALAS2), and the ubiquitously expressed (ALAS1). In the liver, ALAS1 controls the rate-limiting step in the production of heme and hemoproteins that are rapidly turned over in response to metabolic needs. Several heme regulatory targets have been identified as regulators of ALAS1 activity: 1) transcriptional repression via a heme-responsive element, 2) post-transcriptional destabilization of ALAS1 mRNA, 3) post-translational inhibition via a heme regulatory motif, 4) direct inhibition of the activity of the enzyme and 5) breakdown of ALAS1 protein via heme-mediated induction of the protease Lon peptidase 1. In erythroid cells, ALAS2 is a gatekeeper of production of very large amounts of heme necessary for hemoglobin synthesis. The rate of ALAS2 synthesis is transiently increased during the period of active heme synthesis. Its gene expression is determined by trans-activation of nuclear factor GATA1, CACC box and NF-E2-binding sites in the promoter areas. ALAS2 mRNA translation is also regulated by the iron-responsive element (IRE)/iron regulatory proteins (IRP) binding system. In patients, ALAS enzyme activity is affected in most of the mutations causing non-syndromic SA and in several porphyrias. Decreased ALAS2 activity results either directly from loss-of-function ALAS2 mutations as seen in X-linked sideroblastic anemia (XLSA) or from defect in the availability of one of its two mitochondrial substrates: glycine in SLC25A38 mutations and succinyl CoA in GLRX5 mutations. Moreover, ALAS2 gain of function mutations is responsible for X-linked protoporphyria and increased ALAS1 activity lead to acute attacks of hepatic porphyrias. A missense dominant mutation in the Walker A motif of the ATPase binding site in the gene coding for the mitochondrial protein unfoldase CLPX also contributes to increasing ALAS and subsequently protoporphyrinemia. Altogether, these recent data on human ALAS have informed our understanding of porphyrias and sideroblastic anemias pathogeneses and may contribute to new therapeutic strategies.
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Affiliation(s)
- Katell Peoc'h
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France.
| | - Gaël Nicolas
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France.
| | - Caroline Schmitt
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France; AP-HP, HUPNVS, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France.
| | - Arienne Mirmiran
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France.
| | - Raed Daher
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France.
| | - Thibaud Lefebvre
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France; AP-HP, HUPNVS, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France.
| | - Laurent Gouya
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France; AP-HP, HUPNVS, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France.
| | - Zoubida Karim
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France.
| | - Hervé Puy
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, site Bichat, Sorbonne Paris Cité, France, 16 rue Henri Huchard, 75018 Paris, France; Laboratory of Excellence, GR-Ex, Paris, France; AP-HP, HUPNVS, Centre Français des Porphyries, Hôpital Louis Mourier, Colombes, France.
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65
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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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66
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Parker CJ, Desnick RJ, Bissel MD, Bloomer JR, Singal A, Gouya L, Puy H, Anderson KE, Balwani M, Phillips JD. Results of a pilot study of isoniazid in patients with erythropoietic protoporphyria. Mol Genet Metab 2019; 128:309-313. [PMID: 31395332 PMCID: PMC6911826 DOI: 10.1016/j.ymgme.2019.07.017] [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: 09/18/2018] [Revised: 07/29/2019] [Accepted: 07/30/2019] [Indexed: 01/13/2023]
Abstract
Erythropoietic protoporphyria (EPP), the most common porphyria of childhood and the third most common porphyria of adulthood, is characterized clinically by painful, non-blistering cutaneous photosensitivity. Two distinct inheritance patterns involving mutations affecting genes that encode enzymes of the heme biosynthetic pathway underlie the clinical phenotype. Aminolevulinic acid synthase 2 (ALAS2), the rate limiting enzyme of the heme pathway in the erythron, is a therapeutic target in EPP because inhibiting enzyme function would reduce downstream production of protoporphyrin IX (PPIX), preventing accumulation of the toxic molecule and thereby ameliorating symptoms. Isoniazid (INH) is widely used for treatment of latent and active M. tuberculosis (TB). Sideroblastic anemia is observed in some patients taking INH, and studies have shown that this process is a consequence of inhibition of ALAS2 by INH. Based on these observations, we postulated that INH might have therapeutic activity in patients with EPP. We challenged this hypothesis in a murine model of EPP and showed that, after 4 weeks of treatment with INH, both plasma PPIX and hepatic PPIX were significantly reduced. Next, we tested the effect of INH on patients with EPP. After eight weeks, no significant difference in plasma or red cell PPIX was observed among the 15 patients enrolled in the study. These results demonstrate that while INH can lower PPIX in an animal model of EPP, the standard dose used to treat TB is insufficient to affect levels in humans.
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Affiliation(s)
- Charles J Parker
- University of Utah School of Medicine, Salt Lake City, UT, United States of America
| | - Robert J Desnick
- Icahn School of Medicine at Mt. Sinai, New York, NY, United States of America
| | | | - Joseph R Bloomer
- University of Alabama at Birmingham, AL, United States of America
| | - Ashwani Singal
- University of Alabama at Birmingham, AL, United States of America
| | - Laurent Gouya
- Hôpitaux Universitaires Paris Nord Val de Seine, INSERM U1149 CNRS ERL 8252, Université Paris Diderot, Sorbonne Paris Cité, France
| | - Herve Puy
- Hôpitaux Universitaires Paris Nord Val de Seine, INSERM U1149 CNRS ERL 8252, Université Paris Diderot, Sorbonne Paris Cité, France
| | - Karl E Anderson
- University of Texas Medical Branch, Galveston, TX, United States of America
| | - Manisha Balwani
- Icahn School of Medicine at Mt. Sinai, New York, NY, United States of America
| | - John D Phillips
- University of Utah School of Medicine, Salt Lake City, UT, United States of America.
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67
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Daher R, Mansouri A, Martelli A, Bayart S, Manceau H, Callebaut I, Moulouel B, Gouya L, Puy H, Kannengiesser C, Karim Z. GLRX5 mutations impair heme biosynthetic enzymes ALA synthase 2 and ferrochelatase in Human congenital sideroblastic anemia. Mol Genet Metab 2019; 128:342-351. [PMID: 30660387 DOI: 10.1016/j.ymgme.2018.12.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/26/2018] [Accepted: 12/27/2018] [Indexed: 01/20/2023]
Abstract
Non-syndromic microcytic congenital sideroblastic anemia (cSA) is predominantly caused by defective genes encoding for either ALAS2, the first enzyme of heme biosynthesis pathway or SLC25A38, the mitochondrial importer of glycine, an ALAS2 substrate. Herein we explored a new case of cSA with two mutations in GLRX5, a gene for which only two patients have been reported so far. The patient was a young female with biallelic compound heterozygous mutations in GLRX5 (p.Cys67Tyr and p.Met128Lys). Three-D structure analysis confirmed the involvement of Cys67 in the coordination of the [2Fe2S] cluster and suggested a potential role of Met128 in partner interactions. The protein-level of ferrochelatase, the terminal-enzyme of heme process, was increased both in patient-derived lymphoblastoid and CD34+ cells, however, its activity was drastically decreased. The activity of ALAS2 was found altered and possibly related to a defect in the biogenesis of its co-substrate, the succinyl-CoA. Thus, the patient exhibits both a very low ferrochelatase activity without any accumulation of porphyrins precursors in contrast to what is reported in erythropoietic protoporphyria with solely impaired ferrochelatase activity. A significant oxidative stress was evidenced by decreased reduced glutathione and aconitase activity, and increased MnSOD protein expression. This oxidative stress depleted and damaged mtDNA, decreased complex I and IV activities and depleted ATP content. Collectively, our study demonstrates the key role of GLRX5 in modulating ALAS2 and ferrochelatase activities and in maintaining mitochondrial function.
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Affiliation(s)
- Raêd Daher
- INSERM U1149, Centre de Recherche sur l'inflammation (CRI), Paris, France; Université Paris Diderot, site Bichat, Sorbonne Paris cité, DHU UNITY, Paris, France; Laboratory of excellence GR-Ex, Paris, France; AP-HP, Centre Français des Porphyries (CFP), Hôpital Louis Mourier, Colombes, France; AP-HP, Département de Génétique, Hôpital Bichât, Paris, France
| | - Abdellah Mansouri
- INSERM U1149, Centre de Recherche sur l'inflammation (CRI), Paris, France; Université Paris Diderot, site Bichat, Sorbonne Paris cité, DHU UNITY, Paris, France
| | - Alain Martelli
- Department of Translational Medicine and Neurogenetics, Illkirch, France
| | - Sophie Bayart
- Department of Pediatric Hematology, Hôpital Sud, CHU, Rennes, France
| | - Hana Manceau
- INSERM U1149, Centre de Recherche sur l'inflammation (CRI), Paris, France; Université Paris Diderot, site Bichat, Sorbonne Paris cité, DHU UNITY, Paris, France; Laboratory of excellence GR-Ex, Paris, France
| | - Isabelle Callebaut
- CNRS UMR7590, Sorbonne Universités, Université Pierre et Marie Curie-Paris6-MNHN-IRD-IUC, Paris, France
| | - Boualem Moulouel
- AP-HP, Centre Français des Porphyries (CFP), Hôpital Louis Mourier, Colombes, France
| | - Laurent Gouya
- INSERM U1149, Centre de Recherche sur l'inflammation (CRI), Paris, France; Université Paris Diderot, site Bichat, Sorbonne Paris cité, DHU UNITY, Paris, France; Laboratory of excellence GR-Ex, Paris, France; AP-HP, Centre Français des Porphyries (CFP), Hôpital Louis Mourier, Colombes, France
| | - Hervé Puy
- INSERM U1149, Centre de Recherche sur l'inflammation (CRI), Paris, France; Université Paris Diderot, site Bichat, Sorbonne Paris cité, DHU UNITY, Paris, France; Laboratory of excellence GR-Ex, Paris, France; AP-HP, Centre Français des Porphyries (CFP), Hôpital Louis Mourier, Colombes, France.
| | - Caroline Kannengiesser
- INSERM U1149, Centre de Recherche sur l'inflammation (CRI), Paris, France; Université Paris Diderot, site Bichat, Sorbonne Paris cité, DHU UNITY, Paris, France; Laboratory of excellence GR-Ex, Paris, France; AP-HP, Département de Génétique, Hôpital Bichât, Paris, France
| | - Zoubida Karim
- INSERM U1149, Centre de Recherche sur l'inflammation (CRI), Paris, France; Université Paris Diderot, site Bichat, Sorbonne Paris cité, DHU UNITY, Paris, France; Laboratory of excellence GR-Ex, Paris, France.
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Erwin AL, Desnick RJ. Congenital erythropoietic porphyria: Recent advances. Mol Genet Metab 2019; 128:288-297. [PMID: 30685241 PMCID: PMC6597325 DOI: 10.1016/j.ymgme.2018.12.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [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: 12/19/2018] [Accepted: 12/20/2018] [Indexed: 12/11/2022]
Abstract
Congenital erythropoietic porphyria (CEP) is a rare autosomal recessive disorder characterized by photosensitivity and by hematologic abnormalities in affected individuals. CEP is caused by mutations in the uroporphyrinogen synthase (UROS) gene. In three reported cases, CEP has been associated with a specific X-linked GATA1 mutation. Disease-causing mutations in either gene result in absent or markedly reduced UROS enzymatic activity. This in turn leads to the accumulation of the non-physiologic and photoreactive porphyrinogens, uroporphyrinogen I and coproporphyrinogen I, which damage erythrocytes and elicit a phototoxic reaction upon light exposure. The clinical spectrum of CEP depends on the level of residual UROS activity, which is determined by the underlying pathogenic loss-of-function UROS mutations. Disease severity ranges from non-immune hydrops fetalis in utero to late-onset disease with only mild cutaneous involvement. The clinical characteristics of CEP include exquisite photosensitivity to visible light resulting in bullous vesicular lesions which, when infected lead to progressive photomutilation of sun-exposed areas such as the face and hands. In addition, patients have erythrodontia (brownish discoloration of teeth) and can develop corneal scarring. Chronic transfusion-dependent hemolytic anemia is common and leads to bone marrow hyperplasia, which further increases porphyrin production. Management of CEP consists of strict avoidance of exposure to visible light with sun-protective clothing, sunglasses, and car and home window filters. Adequate care of ruptured vesicles and use of topical antibiotics is indicated to prevent superinfections and osteolysis. In patients with symptomatic hemolytic anemia, frequent erythrocyte cell transfusions may be necessary to suppress hematopoiesis and decrease marrow production of the phototoxic porphyrins. In severe transfection-dependent cases, bone marrow or hematopoietic stem cell transplantation has been performed, which is curative. Therapeutic approaches including gene therapy, proteasome inhibition, and pharmacologic chaperones are under investigation.
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Affiliation(s)
| | - Robert J. Desnick
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY
- Address all Correspondence to: R. J. Desnick, PhD, MD, Dean for Genetic and Genomic Medicine Professor and Chairman Emeritus, Department of Genetic and Genomic Sciences Icahn School of Medicine at Mount Sinai New York, NY 10029, Phone: (212) 659-6700 Fax: (212) 360-1809
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Ardalan ZS, Chandran S, Vasudevan A, Angus PW, Grigg A, He S, Macdonald GA, Strasser SI, Tate CJ, Kennedy GA, Testro AG, Gow PJ. Management of Patients With Erythropoietic Protoporphyria-Related Progressive Liver Disease. Liver Transpl 2019; 25:1620-1633. [PMID: 31469227 DOI: 10.1002/lt.25632] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Accepted: 08/10/2019] [Indexed: 12/23/2022]
Abstract
Erythropoietic protoporphyria (EPP) is an inherited metabolic disorder of heme synthesis resulting from overproduction of protoporphyrin IX (PPIX), which can lead to progressive liver disease characterized by recurrent EPP crises and end-stage liver disease. We used the Australian Transplant Registry to identify 5 patients referred for liver transplantation between 2008 and 2017. A total of 4 patients had EPP secondary to ferrochelatase deficiency, and 1 patient had X-linked EPP. No patient had follow-up with a specialist prior to the diagnosis of progressive liver disease. There were 3 patients who underwent orthotopic liver transplantation, whereas 2 died while on the transplant waiting list. Parenteral PPIX-lowering therapy was used in 4 patients and was effective in 3 patients, although 2 of these had rebound porphyria and worsening liver function following a decrease in the intensity of therapy. Early disease recurrence in the allograft following transplantation occurred in 2 patients requiring red cell exchange (RCE) to successfully attain and maintain low PPIX levels, but RCE was associated with hemosiderosis in 1 patient. Allogeneic stem cell transplantation (AlloSCT) was performed in 2 patients. One failed engraftment twice, whereas the second rejected the first graft but achieved full donor chimerism with a second graft and increased immunosuppression. In conclusion, our observations suggest that progressive liver disease needs parenteral PPIX-lowering treatment with the intensity adjusted to achieve a target Erc-PPIX level. Because EPP liver disease is universally recurrent, AlloSCT should be considered in all patients with adequate immunosuppression to facilitate engraftment. RCE appears to be effective for recurrent EPP liver disease but is associated with an increased risk of iron overload.
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Affiliation(s)
- Zaid S Ardalan
- Department of Gastroenterology and Liver Transplant, Austin Hospital, Melbourne, Australia.,Department of Gastroenterology, Alfred Hospital, Melbourne, Australia
| | - Sujievvan Chandran
- Department of Gastroenterology and Liver Transplant, Austin Hospital, Melbourne, Australia
| | - Abhinav Vasudevan
- Department of Gastroenterology, Eastern Health, Melbourne, Australia
| | - Peter W Angus
- Department of Gastroenterology and Liver Transplant, Austin Hospital, Melbourne, Australia.,Melbourne University, Melbourne, Australia
| | - Andrew Grigg
- Department of Clinical Hematology, Austin Hospital, Melbourne, Australia
| | - Simon He
- Department of Clinical Hematology, Austin Hospital, Melbourne, Australia
| | - Graeme A Macdonald
- Department of Gastroenterology and Hepatology, Princess Alexandra Hospital, Brisbane, Australia
| | - Simone I Strasser
- AW Morrow Gastroenterology and Liver Centre, Royal Prince Alfred Hospital, Sydney, Australia.,University of Sydney, Sydney, Australia
| | - Courtney J Tate
- Department of Cancer Care Services, Royal Brisbane and Women's Hospital, Brisbane, Australia.,University of Queensland, Brisbane, Australia
| | - Glen A Kennedy
- Department of Cancer Care Services, Royal Brisbane and Women's Hospital, Brisbane, Australia.,University of Queensland, Brisbane, Australia
| | - Adam G Testro
- Department of Gastroenterology and Liver Transplant, Austin Hospital, Melbourne, Australia
| | - Paul J Gow
- Department of Gastroenterology and Liver Transplant, Austin Hospital, Melbourne, Australia
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Piel RB, Dailey HA, Medlock AE. The mitochondrial heme metabolon: Insights into the complex(ity) of heme synthesis and distribution. Mol Genet Metab 2019; 128:198-203. [PMID: 30709775 PMCID: PMC6640082 DOI: 10.1016/j.ymgme.2019.01.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 12/04/2018] [Accepted: 01/10/2019] [Indexed: 10/27/2022]
Abstract
Heme is an essential cofactor in metazoans that is also toxic in its free state. Heme is synthesized by most metazoans and must be delivered to all cellular compartments for incorporation into a variety of hemoproteins. The heme biosynthesis enzymes have been proposed to exist in a metabolon, a protein complex consisting of interacting enzymes in a metabolic pathway. Metabolons enhance the function of enzymatic pathways by creating favorable microenvironments for pathway enzymes and intermediates, facilitating substrate transport, and providing a scaffold for interactions with other pathways, signaling molecules, or organelles. Herein we detail growing evidence for a mitochondrial heme metabolon and discuss its implications for the study of heme biosynthesis and cellular heme homeostasis.
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Affiliation(s)
- Robert B Piel
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, United States
| | - Harry A Dailey
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, United States; Biomedical and Health Sciences Institute, University of Georgia, Athens, GA 30602, United States; Department of Microbiology, University of Georgia, Athens, GA, 30602, United States
| | - Amy E Medlock
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, United States; Biomedical and Health Sciences Institute, University of Georgia, Athens, GA 30602, United States; Augusta University-University of Georgia, Medical Partnership, Athens, GA 30602, United States.
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71
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Genome-wide microhomologies enable precise template-free editing of biologically relevant deletion mutations. Nat Commun 2019; 10:4856. [PMID: 31649251 PMCID: PMC6813315 DOI: 10.1038/s41467-019-12829-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 09/30/2019] [Indexed: 02/06/2023] Open
Abstract
The functional effect of a gene edit by designer nucleases depends on the DNA repair outcome at the targeted locus. While non-homologous end joining (NHEJ) repair results in various mutations, microhomology-mediated end joining (MMEJ) creates precise deletions based on the alignment of flanking microhomologies (µHs). Recently, the sequence context surrounding nuclease-induced double strand breaks (DSBs) has been shown to predict repair outcomes, for which µH plays an important role. Here, we survey naturally occurring human deletion variants and identify that 11 million or 57% are flanked by µHs, covering 88% of protein-coding genes. These biologically relevant mutations are candidates for precise creation in a template-free manner by MMEJ repair. Using CRISPR-Cas9 in human induced pluripotent stem cells (hiPSCs), we efficiently create pathogenic deletion mutations for demonstrable disease models with both gain- and loss-of-function phenotypes. We anticipate this dataset and gene editing strategy to enable functional genetic studies and drug screening.
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72
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Wang P, Sachar M, Lu J, Shehu AI, Zhu J, Chen J, Liu K, Anderson KE, Xie W, Gonzalez FJ, Klaassen CD, Ma X. The essential role of the transporter ABCG2 in the pathophysiology of erythropoietic protoporphyria. SCIENCE ADVANCES 2019; 5:eaaw6127. [PMID: 31555729 PMCID: PMC6750912 DOI: 10.1126/sciadv.aaw6127] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Accepted: 08/23/2019] [Indexed: 06/10/2023]
Abstract
Erythropoietic protoporphyria (EPP) is an inherited disease caused by loss-of-function mutations of ferrochelatase, an enzyme in the heme biosynthesis pathway that converts protoporphyrin IX (PPIX) into heme. PPIX accumulation in patients with EPP leads to phototoxicity and hepatotoxicity, and there is no cure. Here, we demonstrated that the PPIX efflux transporter ABCG2 (also called BCRP) determines EPP-associated phototoxicity and hepatotoxicity. We found that ABCG2 deficiency decreases PPIX distribution to the skin and therefore prevents EPP-associated phototoxicity. We also found that ABCG2 deficiency protects against EPP-associated hepatotoxicity by modulating PPIX distribution, metabolism, and excretion. In summary, our work has uncovered an essential role of ABCG2 in the pathophysiology of EPP, which suggests the potential for novel strategies in the development of therapy for EPP.
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Affiliation(s)
- Pengcheng Wang
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Madhav Sachar
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jie Lu
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Amina I. Shehu
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Junjie Zhu
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Jing Chen
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Ke Liu
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Karl E. Anderson
- Porphyria Laboratory and Center, Departments of Preventive Medicine and Community Health, and Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Wen Xie
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Frank J. Gonzalez
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, MD 20892, USA
| | - Curtis D. Klaassen
- Department of Pharmacology, Toxicology and Therapeutics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Xiaochao Ma
- Center for Pharmacogenetics, Department of Pharmaceutical Sciences, School of Pharmacy, University of Pittsburgh, Pittsburgh, PA 15261, USA
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Stölzel U, Doss MO, Schuppan D. Clinical Guide and Update on Porphyrias. Gastroenterology 2019; 157:365-381.e4. [PMID: 31085196 DOI: 10.1053/j.gastro.2019.04.050] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2018] [Revised: 04/07/2019] [Accepted: 04/10/2019] [Indexed: 12/24/2022]
Abstract
Physicians should be aware of porphyrias, which could be responsible for unexplained gastrointestinal, neurologic, or skin disorders. Despite their relative rarity and complexity, most porphyrias can be easily defined and diagnosed. They are caused by well-characterized enzyme defects in the complex heme biosynthetic pathway and are divided into categories of acute vs non-acute or hepatic vs erythropoietic porphyrias. Acute hepatic porphyrias (acute intermittent porphyria, variegate porphyria, hereditary coproporphyria, and aminolevulinic acid dehydratase deficient porphyria) manifest in attacks and are characterized by overproduction of porphyrin precursors, producing often serious abdominal, psychiatric, neurologic, or cardiovascular symptoms. Patients with variegate porphyria and hereditary coproporphyria can present with skin photosensitivity. Diagnosis relies on measurement of increased urinary 5-aminolevulinic acid (in patients with aminolevulinic acid dehydratase deficient porphyria) or increased 5-aminolevulinic acid and porphobilinogen (in patients with other acute porphyrias). Management of attacks requires intensive care, strict avoidance of porphyrinogenic drugs and other precipitating factors, caloric support, and often heme therapy. The non-acute porphyrias are porphyria cutanea tarda, erythropoietic protoporphyria, X-linked protoporphyria, and the rare congenital erythropoietic porphyria. They lead to the accumulation of porphyrins that cause skin photosensitivity and occasionally severe liver damage. Secondary elevated urinary or blood porphyrins can occur in patients without porphyria, for example, in liver diseases, or iron deficiency. Increases in porphyrin precursors and porphyrins are also found in patients with lead intoxication. Patients with porphyria cutanea tarda benefit from iron depletion, hydroxychloroquine therapy, and, if applicable, elimination of the hepatitis C virus. An α-melanocyte-stimulating hormone analogue can reduce sunlight sensitivity in patients with erythropoietic protoporphyria or X-linked protoporphyria. Strategies to address dysregulated or dysfunctional steps within the heme biosynthetic pathway are in development.
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Affiliation(s)
- Ulrich Stölzel
- Saxony Porphyria Center, Department of Internal Medicine II, Klinikum Chemnitz, Chemnitz, Germany
| | - Manfred O Doss
- German Competence Center for Porphyria Diagnosis and Consultation, Marburg, Germany; Institute of Translational Immunology and Research Center for Immune Therapy, University Medical Center, Johannes Gutenberg University, Mainz, Germany
| | - Detlef Schuppan
- Institute of Translational Immunology and Research Center for Immune Therapy, University Medical Center, Johannes Gutenberg University, Mainz, Germany; Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts.
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Maitra D, Bragazzi Cunha J, Elenbaas JS, Bonkovsky HL, Shavit JA, Omary MB. Porphyrin-Induced Protein Oxidation and Aggregation as a Mechanism of Porphyria-Associated Cell Injury. Cell Mol Gastroenterol Hepatol 2019; 8:535-548. [PMID: 31233899 PMCID: PMC6820234 DOI: 10.1016/j.jcmgh.2019.06.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 06/14/2019] [Accepted: 06/14/2019] [Indexed: 12/12/2022]
Abstract
Genetic porphyrias comprise eight diseases caused by defects in the heme biosynthetic pathway that lead to accumulation of heme precursors. Consequences of porphyria include photosensitivity, liver damage and increased risk of hepatocellular carcinoma, and neurovisceral involvement, including seizures. Fluorescent porphyrins that include protoporphyrin-IX, uroporphyrin and coproporphyrin, are photo-reactive; they absorb light energy and are excited to high-energy singlet and triplet states. Decay of the porphyrin excited to ground state releases energy and generates singlet oxygen. Porphyrin-induced oxidative stress is thought to be the major mechanism of porphyrin-mediated tissue damage. Although this explains the acute photosensitivity in most porphyrias, light-induced porphyrin-mediated oxidative stress does not account for the effect of porphyrins on internal organs. Recent findings demonstrate the unique role of fluorescent porphyrins in causing subcellular compartment-selective protein aggregation. Porphyrin-mediated protein aggregation associates with nuclear deformation, cytoplasmic vacuole formation and endoplasmic reticulum dilation. Porphyrin-triggered proteotoxicity is compounded by inhibition of the proteasome due to aggregation of some of its subunits. The ensuing disruption in proteostasis also manifests in cell cycle arrest coupled with aggregation of cell proliferation-related proteins, including PCNA, cdk4 and cyclin B1. Porphyrins bind to native proteins and, in presence of light and oxygen, oxidize several amino acids, particularly methionine. Noncovalent interaction of oxidized proteins with porphyrins leads to formation of protein aggregates. In internal organs, particularly the liver, light-independent porphyrin-mediated protein aggregation occurs after secondary triggers of oxidative stress. Thus, porphyrin-induced protein aggregation provides a novel mechanism for external and internal tissue damage in porphyrias that involve fluorescent porphyrin accumulation.
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Affiliation(s)
- Dhiman Maitra
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan.
| | - Juliana Bragazzi Cunha
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Jared S Elenbaas
- Medical Scientist Training Program, Washington University in St. Louis, St. Louis, Missouri
| | - Herbert L Bonkovsky
- Gastroenterology & Hepatology, and Molecular Medicine & Translational Science, Wake Forest University School of Medicine/NC Baptist Hospital, Winston-Salem, North Carolina
| | - Jordan A Shavit
- Department of Pediatrics, Division of Pediatric Hematology and Oncology, University of Michigan Medical School, Ann Arbor, Michigan
| | - M Bishr Omary
- Department of Molecular and Integrative Physiology, University of Michigan Medical School, Ann Arbor, Michigan; Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, Michigan; Cell Biology, Faculty of Science and Technology, Åbo Akademi University, Turku, Finland
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Molecular expression, characterization and mechanism of ALAS2 gain-of-function mutants. Mol Med 2019; 25:4. [PMID: 30678654 PMCID: PMC6344999 DOI: 10.1186/s10020-019-0070-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 01/02/2019] [Indexed: 11/13/2022] Open
Abstract
Background X-linked protoporphyria (XLP) (MIM 300752) is an erythropoietic porphyria due to gain-of-function mutations in the last exon (Ducamp et al., Hum Mol Genet 22:1280-88, 2013) of the erythroid-specific aminolevulinate synthase gene (ALAS2). Five ALAS2 exon 11 variants identified by the NHBLI Exome sequencing project (p.R559H, p.E565D, p.R572C, p.S573F and p.Y586F) were expressed, purified and characterized in order to assess their possible contribution to XLP. To further characterize the XLP gain-of-function region, five novel ALAS2 truncation mutations (p.P561X, p.V562X, p.H563X, p.E569X and p.F575X) were also expressed and studied. Methods Site-directed mutagenesis was used to generate ALAS2 mutant clones and all were prokaryotically expressed, purified to near homogeneity and characterized by protein and enzyme kinetic assays. Standard deviations were calculated for 3 or more assay replicates. Results The five ALAS2 single nucleotide variants had from 1.3- to 1.9-fold increases in succinyl-CoA Vmax and 2- to 3-fold increases in thermostability suggesting that most could be gain-of-function modifiers of porphyria instead of causes. One SNP (p.R559H) had markedly low purification yield indicating enzyme instability as the likely cause for XLSA in an elderly patient with x-linked sideroblastic anemia. The five novel ALAS2 truncation mutations had increased Vmax values for both succinyl-CoA and glycine substrates (1.4 to 5.6-fold over wild-type), while the Kms for both substrates were only modestly changed. Of interest, the thermostabilities of the truncated ALAS2 mutants were significantly lower than wild-type, with an inverse relationship to Vmax fold-increase. Conclusions Patients with porphyrias should always be assessed for the presence of the ALAS2 gain-of-function modifier variants identified here. A key region of the ALAS2 carboxyterminal region is identified by the truncation mutations studied here and the correlation of increased thermolability with activity suggests that increased molecular flexibility/active site openness is the mechanism of enhanced function of mutations in this region providing further insights into the role of the carboxyl-terminal region of ALAS2 in the regulation of erythroid heme synthesis. Electronic supplementary material The online version of this article (10.1186/s10020-019-0070-9) contains supplementary material, which is available to authorized users.
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77
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Ducamp S, Fleming MD. The molecular genetics of sideroblastic anemia. Blood 2019; 133:59-69. [PMID: 30401706 PMCID: PMC6318428 DOI: 10.1182/blood-2018-08-815951] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 09/21/2018] [Indexed: 01/19/2023] Open
Abstract
The sideroblastic anemias (SAs) are a group of inherited and acquired bone marrow disorders defined by pathological iron accumulation in the mitochondria of erythroid precursors. Like most hematological diseases, the molecular genetic basis of the SAs has ridden the wave of technology advancement. Within the last 30 years, with the advent of positional cloning, the human genome project, solid-state genotyping technologies, and next-generation sequencing have evolved to the point where more than two-thirds of congenital SA cases, and an even greater proportion of cases of acquired clonal disease, can be attributed to mutations in a specific gene or genes. This review focuses on an analysis of the genetics of these diseases and how understanding these defects may contribute to the design and implementation of rational therapies.
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Affiliation(s)
- Sarah Ducamp
- Department of Pathology, Boston Children's Hospital, Boston, MA
| | - Mark D Fleming
- Department of Pathology, Boston Children's Hospital, Boston, MA
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Abstract
Mitochondria are an iconic distinguishing feature of eukaryotic cells. Mitochondria encompass an active organellar network that fuses, divides, and directs a myriad of vital biological functions, including energy metabolism, cell death regulation, and innate immune signaling in different tissues. Another crucial and often underappreciated function of these dynamic organelles is their central role in the metabolism of the most abundant and biologically versatile transition metals in mammalian cells, iron. In recent years, cellular and animal models of mitochondrial iron dysfunction have provided vital information in identifying new proteins that have elucidated the pathways involved in mitochondrial homeostasis and iron metabolism. Specific signatures of mitochondrial iron dysregulation that are associated with disease pathogenesis and/or progression are becoming increasingly important. Understanding the molecular mechanisms regulating mitochondrial iron pathways will help better define the role of this important metal in mitochondrial function and in human health and disease.
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Affiliation(s)
- Diane M Ward
- Department of Pathology, University of Utah School of Medicine, Salt Lake City, Utah 84112, USA
| | - Suzanne M Cloonan
- Division of Pulmonary and Critical Care Medicine, Weill Cornell Medicine, New York, NY 10065, USA;
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Kakoullis L, Louppides S, Papachristodoulou E, Panos G. Porphyrias and photosensitivity: pathophysiology for the clinician. Postgrad Med 2018; 130:673-686. [PMID: 30296862 DOI: 10.1080/00325481.2018.1533380] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Porphyrias are disorders caused by defects in the biosynthetic pathway of heme. Their manifestations can be divided into three distinct syndromes, each attributable to the accumulation of three distinct classes of molecules. The acute neurovisceral syndrome is caused by the accumulation of the neurotoxic porphyrin precursors, delta aminolevulinic acid, and porphobilinogen; the syndrome of immediate painful photosensitivity is caused by the lipid-soluble protoporphyrin IX and, the syndrome of delayed blistering photosensitivity, caused by the water-soluble porphyrins, uroporphyrin, and coproporphyrin. Porphyrias can manifest with one, or with a combination, of these syndromes, depending on whether one or more types of molecules are being accumulated. Iron plays a significant role in some of these conditions, as evidenced by improvements in both clinical manifestations and laboratory parameters, following iron depletion in porphyria cutanea tarda, or iron administration in some cases of X-linked erythropoietic protoporphyria. While the pathophysiology of a specific type of porphyrias, the protoporphyrias, appears to favor the administration of zinc, results so far have been conflicting, necessitating further studies in order to assess its potential benefit. The pathways involved in each disease, as well as insights into their pathobiological processes are presented, with an emphasis on the development of photosensitivity reactions.
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Affiliation(s)
- Loukas Kakoullis
- a Department of Internal Medicine , Nicosia General Hospital, University of Cyprus Medical School , Nicosia , Cyprus
| | - Stylianos Louppides
- a Department of Internal Medicine , Nicosia General Hospital, University of Cyprus Medical School , Nicosia , Cyprus
| | - Eleni Papachristodoulou
- a Department of Internal Medicine , Nicosia General Hospital, University of Cyprus Medical School , Nicosia , Cyprus
| | - George Panos
- a Department of Internal Medicine , Nicosia General Hospital, University of Cyprus Medical School , Nicosia , Cyprus.,b Department of Internal Medicine, Section of Infectious Diseases , Patras University General Hospital, University of Patras School of Medicine , Patras , Greece
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81
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Gou E, Weng C, Greene T, Anderson KE, Phillips JD. Longitudinal Analysis of Erythrocyte and Plasma Protoporphyrin Levels in Patients with Protoporphyria. J Appl Lab Med 2018; 3:213-221. [DOI: 10.1373/jalm.2017.025874] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2017] [Accepted: 03/26/2018] [Indexed: 11/06/2022]
Abstract
Abstract
Background
Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are inherited cutaneous porphyrias resulting from decreased activity of ferrochelatase and gain-of-function mutations of δ-aminolevulinic acid synthase-2, respectively. Both of these protoporphyrias cause increased protoporphyrin levels that cause photosensitivity and may lead to hepatopathy and further increases in erythrocyte and plasma porphyrin levels.
Methods
We evaluated erythrocyte protoporphyrin and plasma porphyrin levels in all subjects with EPP (83 subjects) or XLP (9 subjects) without evidence of liver disease tested repeatedly at a single laboratory over 25 years.
Results
Intersubject variation contributed more than intrasubject variation (78.86% vs 21.14%) to overall variability, and longitudinal variability, estimated by CV, averaged 26%. Erythrocyte total protoporphyrin levels were similar in males and females with EPP (ratio, 0.99; 95% CI, 0.82–1.21; P = 0.96) but were higher in males than females with XLP, although this difference was not statistically significant (ratio, 0.76; 95% CI, 0.43–1.36; P = 0.35). Analysis of 20 subjects from 9 separate families showed significant effects of family compared with effects of individual variation on total variance (50% vs 25%; P < 0.0001).
Conclusion
Variation of erythrocyte total protoporphyrin up to 25% is expected in patients with protoporphyria, whereas greater increases might raise concern for protoporphyric hepatopathy.
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Affiliation(s)
- Eric Gou
- University of Texas Medical Branch, Galveston, TX
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82
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Anti-Correlation between the Dynamics of the Active Site Loop and C-Terminal Tail in Relation to the Homodimer Asymmetry of the Mouse Erythroid 5-Aminolevulinate Synthase. Int J Mol Sci 2018; 19:ijms19071899. [PMID: 29958424 PMCID: PMC6073955 DOI: 10.3390/ijms19071899] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 06/21/2018] [Accepted: 06/22/2018] [Indexed: 11/17/2022] Open
Abstract
Biosynthesis of heme represents a complex process that involves multiple stages controlled by different enzymes. The first of these proteins is a pyridoxal 5′-phosphate (PLP)-dependent homodimeric enzyme, 5-aminolevulinate synthase (ALAS), that catalyzes the rate-limiting step in heme biosynthesis, the condensation of glycine with succinyl-CoA. Genetic mutations in human erythroid-specific ALAS (ALAS2) are associated with two inherited blood disorders, X-linked sideroblastic anemia (XLSA) and X-linked protoporphyria (XLPP). XLSA is caused by diminished ALAS2 activity leading to decreased ALA and heme syntheses and ultimately ineffective erythropoiesis, whereas XLPP results from “gain-of-function” ALAS2 mutations and consequent overproduction of protoporphyrin IX and increase in Zn2+-protoporphyrin levels. All XLPP-linked mutations affect the intrinsically disordered C-terminal tail of ALAS2. Our earlier molecular dynamics (MD) simulation-based analysis showed that the activity of ALAS2 could be regulated by the conformational flexibility of the active site loop whose structural features and dynamics could be changed due to mutations. We also revealed that the dynamic behavior of the two protomers of the ALAS2 dimer differed. However, how the structural dynamics of ALAS2 active site loop and C-terminal tail dynamics are related to each other and contribute to the homodimer asymmetry remained unanswered questions. In this study, we used bioinformatics and computational biology tools to evaluate the role(s) of the C-terminal tail dynamics in the structure and conformational dynamics of the murine ALAS2 homodimer active site loop. To assess the structural correlation between these two regions, we analyzed their structural displacements and determined their degree of correlation. Here, we report that the dynamics of ALAS2 active site loop is anti-correlated with the dynamics of the C-terminal tail and that this anti-correlation can represent a molecular basis for the functional and dynamic asymmetry of the ALAS2 homodimer.
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83
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Kafina MD, Paw BH. Intracellular iron and heme trafficking and metabolism in developing erythroblasts. Metallomics 2018; 9:1193-1203. [PMID: 28795723 DOI: 10.1039/c7mt00103g] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Vertebrate red blood cells (RBCs) arise from erythroblasts in the human bone marrow through a process known as erythropoiesis. Iron uptake is a crucial hallmark, essential for heme biosynthesis in the differentiating erythroblasts, which are dedicated to producing hemoglobin. Erythropoiesis is facilitated by a network of intracellular transport proteins, chaperones, and circulating hormones. Intracellular iron is targeted to the mitochondria for incorporation into a porphyrin ring to form heme and cytosolic iron-sulfur proteins, including Iron Regulatory Protein 1 (IRP1). These processes are tightly regulated to prevent both excess and insufficient levels of iron and heme precursors. Crosstalk between the heme and iron-sulfur synthesizing pathways has been demonstrated to serve as a regulatory feedback mechanism. The activity of δ-aminolevulinic acid synthase (ALAS), the first and rate-limiting enzyme of heme biosynthesis, is a fundamental node of this regulation. Recently, the mitochondrial unfoldase, ClpX, has received attention as a novel key player that modulates this step in heme biogenesis, implicating a role in the pathophysiology of anemic diseases. This chapter reviews the canonical pathways in intracellular iron and heme trafficking and recent findings of iron and heme metabolism in vertebrate red cells. A discussion of the molecular approaches to studying iron and heme transport is provided to highlight opportunities for revealing therapeutic targets.
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Affiliation(s)
- Martin D Kafina
- Department of Medicine, Hematology Division, Brigham & Women's Hospital, Boston, Massachusetts 02115, USA
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84
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Coffey A, Leung DH, Quintanilla NM. Erythropoietic Protoporphyria: Initial Diagnosis With Cholestatic Liver Disease. Pediatrics 2018; 141:S445-S450. [PMID: 29610169 DOI: 10.1542/peds.2016-1625] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/16/2017] [Indexed: 11/24/2022] Open
Abstract
The porphyrias are a group of rare metabolic disorders that result from defects in heme biosynthesis. Erythropoietic protoporphyria (EPP) is the most common inherited porphyria in children and is diagnosed in most individuals after the onset of cutaneous manifestations. Hepatobiliary disease affects the minority of individuals with EPP and usually manifests in patients with an established diagnosis of EPP. We report on a classic but rare case of EPP that masqueraded as cholestasis. An 8-year-old boy was referred to the Hepatology Clinic after an abrupt onset of jaundice with a longstanding history of dermatitis. The diagnosis of EPP was established with liver biopsy, which revealed dense, dark-brown pigment in hepatocytes and Kupffer cells that, on polarization, displayed bright-red birefringence and centrally located Maltese crosses. Plasma total porphyrins and erythrocyte protoporphyrin were elevated and confirmed a diagnosis of EPP. We hope to raise awareness of this diagnosis among pediatricians, hepatologists, and pathologists and increase the consideration of EPP in patients with cholestatic liver disease and chronic dermatitis.
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Affiliation(s)
- Amy Coffey
- Departments of Pathology and Immunology and.,Department of Pathology, Texas Children's Hospital, Houston, Texas
| | - Daniel H Leung
- Pediatrics, Baylor College of Medicine, Houston, Texas; and.,Division of Pediatric Gastroenterology, Hepatology, and Nutrition and
| | - Norma M Quintanilla
- Departments of Pathology and Immunology and .,Department of Pathology, Texas Children's Hospital, Houston, Texas
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85
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The role of ClpX in erythropoietic protoporphyria. Hematol Transfus Cell Ther 2018; 40:182-188. [PMID: 30057992 PMCID: PMC6001922 DOI: 10.1016/j.htct.2018.03.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 03/02/2018] [Indexed: 12/30/2022] Open
Abstract
Hemoglobin is an essential biological component of human physiology and its production in red blood cells relies upon proper biosynthesis of heme and globin protein. Disruption in the synthesis of these precursors accounts for a number of human blood disorders found in patients. Mutations in genes encoding heme biosynthesis enzymes are associated with a broad class of metabolic disorders called porphyrias. In particular, one subtype - erythropoietic protoporphyria - is caused by the accumulation of protoporphyrin IX. Erythropoietic protoporphyria patients suffer from photosensitivity and a higher risk of liver failure, which is the principle cause of morbidity and mortality. Approximately 90% of these patients carry loss-of-function mutations in the enzyme ferrochelatase (FECH), while 5% of cases are associated with activating mutations in the C-terminus of ALAS2. Recent work has begun to uncover novel mechanisms of heme regulation that may account for the remaining 5% of cases with previously unknown genetic basis. One erythropoietic protoporphyria family has been identified with inherited mutations in the AAA+ protease ClpXP that regulates ALAS activity. In this review article, recent findings on the role of ClpXP as both an activating unfoldase and degrading protease and its impact on heme synthesis will be discussed. This review will also highlight the role of ClpX dysfunction in erythropoietic protoporphyria.
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86
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Brown BL, Kardon JR, Sauer RT, Baker TA. Structure of the Mitochondrial Aminolevulinic Acid Synthase, a Key Heme Biosynthetic Enzyme. Structure 2018; 26:580-589.e4. [PMID: 29551290 DOI: 10.1016/j.str.2018.02.012] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 11/30/2017] [Accepted: 02/09/2018] [Indexed: 01/19/2023]
Abstract
5-Aminolevulinic acid synthase (ALAS) catalyzes the first step in heme biosynthesis. We present the crystal structure of a eukaryotic ALAS from Saccharomyces cerevisiae. In this homodimeric structure, one ALAS subunit contains covalently bound cofactor, pyridoxal 5'-phosphate (PLP), whereas the second is PLP free. Comparison between the subunits reveals PLP-coupled reordering of the active site and of additional regions to achieve the active conformation of the enzyme. The eukaryotic C-terminal extension, a region altered in multiple human disease alleles, wraps around the dimer and contacts active-site-proximal residues. Mutational analysis demonstrates that this C-terminal region that engages the active site is important for ALAS activity. Our discovery of structural elements that change conformation upon PLP binding and of direct contact between the C-terminal extension and the active site thus provides a structural basis for investigation of disruptions in the first step of heme biosynthesis and resulting human disorders.
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Affiliation(s)
- Breann L Brown
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Julia R Kardon
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Robert T Sauer
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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87
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Teramura T, Mizuno M, Asano H, Naru E, Kawara S, Kamide R, Kawada A. Prevention of photosensitivity with action spectrum adjusted protection for erythropoietic protoporphyria. J Dermatol 2018; 45:145-149. [PMID: 29266358 PMCID: PMC5814858 DOI: 10.1111/1346-8138.14175] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 11/08/2017] [Indexed: 12/24/2022]
Abstract
Erythropoietic protoporphyria is a genetic disease characterized by sensitivity to sunlight caused by the accumulation of protoporphyrin IX. Photoprotection against ultraviolet A and visible light is necessary for erythropoietic porphyria patients because the absorption spectrum of protoporphyrin IX lies in both ultraviolet A and visible light region. We developed a novel index, in vitro porphyrin protection factor, based on the protoporphyrin IX absorbance spectrum. We also selected appropriate photoprotective products designed according to protoporphyrin IX absorbance. The porphyrin protection factors of a combination of make-up base with a powder as well as with a liquid foundation were significantly higher than those of a conventional sunscreen product, even at a small application dose. An in-use test carried out for 6 months showed that the efficacy of these products was 78.3%, and no adverse reactions were observed. Male subjects preferred liquid foundation, whereas all female subjects used powder foundation. The preference of the subjects could lead to the long-term use of the tested products. In conclusion, this study provided a new approach to improve photoprotection in erythropoietic protoporphyria patients.
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Affiliation(s)
| | - Makoto Mizuno
- Fundamental Research LaboratoriesKOSÉ CorporationTokyoJapan
| | - Hajime Asano
- Fundamental Research LaboratoriesKOSÉ CorporationTokyoJapan
| | - Eiji Naru
- Fundamental Research LaboratoriesKOSÉ CorporationTokyoJapan
| | - Shigeru Kawara
- Department of DermatologyJapanese Red Cross Kanazawa HospitalIshikawaJapan
| | - Ryoichi Kamide
- Hihuno Clinic NingyochoTokyoJapan
- Department of DermatologyDaisan HospitalThe Jikei University School of MedicineTokyoJapan
| | - Akira Kawada
- Department of DermatologyKindai University Faculty of MedicineOsakaJapan
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88
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89
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Biewenga M, Matawlie RHS, Friesema ECH, Koole-Lesuis H, Langeveld M, Wilson JHP, Langendonk JG. Osteoporosis in patients with erythropoietic protoporphyria. Br J Dermatol 2017; 177:1693-1698. [PMID: 28815553 DOI: 10.1111/bjd.15893] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/04/2017] [Indexed: 12/25/2022]
Abstract
BACKGROUND Erythropoietic protoporphyria (EPP) is a rare metabolic disease with painful photosensitivity due to protoporphyrin IX accumulation. OBJECTIVES To evaluate bone mineral density (BMD) and known osteoporosis risk factors in patients with EPP. METHODS Patients with EPP attending the Erasmus MC outpatient clinic who had undergone BMD measurements were included. Plasma 25 hydroxy (OH) vitamin D, alkaline phosphatase, parathyroid hormone and total protoporphyrin IX levels were measured; information on lifestyle, sunlight exposure and a bone-relevant physical exercise index [Bone Physical Activity Questionnaire (BPAQ) score] was obtained via questionnaires. BMD scores and the prevalence of osteopenia and osteoporosis in the EPP population were compared with a reference population. RESULTS Forty-four patients with EPP (23 female, 21 male; mean age 37·6 years) were included. The mean SDs of the T-scores were -1·12 for the lumbar spine and -0·82 for the femoral neck (both P < 0·001). Osteopenia was present in 36%; osteoporosis in 23%. Based on the reference population the expected prevalence was 15% and 1%, respectively. Prevalence of vitamin D deficiency was 50% (defined as a 25-OH vitamin D level < 50 nmol L-1 ). Mean self-reported BPAQ score was 19·4 units (reference interval 19-24). Multiple linear regression analysis showed a significant influence of vitamin D deficiency and bone-relevant physical exercise score on BMD in patients with EPP. CONCLUSIONS The prevalence of osteoporosis and osteopenia is greatly increased in patients with EPP. Alkaline phosphatase (related to vitamin D deficiency) and amount of weight-bearing exercise are significantly correlated with low BMD in this population.
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Affiliation(s)
- M Biewenga
- Department of Internal Medicine, Porphyria Centre, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, PO Box 2040, 3000, CA Rotterdam, the Netherlands
| | - R H S Matawlie
- Department of Internal Medicine, Porphyria Centre, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, PO Box 2040, 3000, CA Rotterdam, the Netherlands
| | - E C H Friesema
- Department of Internal Medicine, Porphyria Centre, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, PO Box 2040, 3000, CA Rotterdam, the Netherlands
| | - H Koole-Lesuis
- Department of Internal Medicine, Porphyria Centre, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, PO Box 2040, 3000, CA Rotterdam, the Netherlands
| | - M Langeveld
- Department of Internal Medicine, Porphyria Centre, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, PO Box 2040, 3000, CA Rotterdam, the Netherlands
| | - J H P Wilson
- Department of Internal Medicine, Porphyria Centre, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, PO Box 2040, 3000, CA Rotterdam, the Netherlands
| | - J G Langendonk
- Department of Internal Medicine, Porphyria Centre, Centre for Lysosomal and Metabolic Diseases, Erasmus MC, PO Box 2040, 3000, CA Rotterdam, the Netherlands
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90
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Veitia RA, Caburet S, Birchler JA. Mechanisms of Mendelian dominance. Clin Genet 2017; 93:419-428. [PMID: 28755412 DOI: 10.1111/cge.13107] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Revised: 07/24/2017] [Accepted: 07/26/2017] [Indexed: 01/12/2023]
Abstract
Genetic dominance has long been considered as a qualitative reflection of interallelic interactions. Dominance arises from many multiple sources whose unifying theme is the existence of non-linear relationships between the genotypic and phenotypic values. One of the clearest examples are dominant negative mutations (DNMs) in which a defective subunit poisons a macromolecular complex. Dominance can also be due to the presence of a heterozygous null allele, as is the case of haploinsufficiency. Dominance can also be influenced by epistatic (interloci) interactions. For instance, a pre-existing genetic variant can make possible the expression of a pathogenic variant in a seemingly "dominant" fashion. Such interactions, which can make an individual more or less sensitive to a particular pathogenic variant, will also be discussed here.
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Affiliation(s)
- R A Veitia
- Institut Jacques Monod, CNRS-UMR 7592, Paris Cedex 13, France.,Université Paris Diderot, Paris, France
| | - S Caburet
- Institut Jacques Monod, CNRS-UMR 7592, Paris Cedex 13, France.,Université Paris Diderot, Paris, France
| | - J A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, Missouri
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91
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Acute hepatic and erythropoietic porphyrias: from ALA synthases 1 and 2 to new molecular bases and treatments. Curr Opin Hematol 2017; 24:198-207. [PMID: 28118224 DOI: 10.1097/moh.0000000000000330] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
PURPOSE OF REVIEW Many studies over the past decade have together identified new genes including modifier genes and new regulation and pathophysiological mechanisms in inherited inborn diseases of the heme biosynthetic pathway. A new porphyria has been characterized: X-linked protoporphyria and the perspective to have innovative treatment at very short-term became a reality. We will summarize how recent data on both ALAS1 and ALAS2 have informed our understanding of disease pathogenesis with an emphasis on how this information may contribute to new therapeutic strategies. RECENT FINDINGS The development of clinical and biological porphyria networks improved the long-term follow up of cohorts. The ageing of patients have allowed for the identification of novel recurrently mutated genes, and highlighted long-term complications in acute hepatic porphyrias. The treatment of hepatic porphyrias by an RNAi-targeting hepatic ALAS1 is actually tested and may lead to improve the management of acute attacks.In erythropoietic porphyrias, the key role of ALAS2 as a gate keeper of the heme and subsequently hemoglobin synthesis has been demonstrated. Its implication as a modifier gene in over erythroid disorders has also been documented. SUMMARY The knowledge of both the genetic abnormalities and the regulation of heme biosynthesis has increased over the last 5 years and open new avenues in the management of erythropoietic and acute hepatic porphyrias.
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92
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Zhou ZD, Tan EK. Iron regulatory protein (IRP)-iron responsive element (IRE) signaling pathway in human neurodegenerative diseases. Mol Neurodegener 2017; 12:75. [PMID: 29061112 PMCID: PMC5654065 DOI: 10.1186/s13024-017-0218-4] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Accepted: 10/17/2017] [Indexed: 12/13/2022] Open
Abstract
The homeostasis of iron is vital to human health, and iron dyshomeostasis can lead to various disorders. Iron homeostasis is maintained by iron regulatory proteins (IRP1 and IRP2) and the iron-responsive element (IRE) signaling pathway. IRPs can bind to RNA stem-loops containing an IRE in the untranslated region (UTR) to manipulate translation of target mRNA. However, iron can bind to IRPs, leading to the dissociation of IRPs from the IRE and altered translation of target transcripts. Recently an IRE is found in the 5′-UTR of amyloid precursor protein (APP) and α-synuclein (α-Syn) transcripts. The levels of α-Syn, APP and amyloid β-peptide (Aβ) as well as protein aggregation can be down-regulated by IRPs but are up-regulated in the presence of iron accumulation. Therefore, inhibition of the IRE-modulated expression of APP and α-Syn or chelation of iron in patient’s brains has therapeutic significance to human neurodegenerative diseases. Currently, new pre-drug IRE inhibitors with therapeutic effects have been identified and are at different stages of clinical trials for human neurodegenerative diseases. Although some promising drug candidates of chemical IRE inhibitors and iron-chelating agents have been identified and are being validated in clinical trials for neurodegenerative diseases, future studies are expected to further establish the clinical efficacy and safety of IRE inhibitors and iron-chelating agents in patients with neurodegenerative diseases.
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Affiliation(s)
- Zhi Dong Zhou
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore. .,Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, 169857, Singapore.
| | - Eng-King Tan
- National Neuroscience Institute of Singapore, 11 Jalan Tan Tock Seng, Singapore, 308433, Singapore.,Department of Neurology, Singapore General Hospital, Outram Road, Singapore, 169608, Singapore.,Signature Research Program in Neuroscience and Behavioral Disorders, Duke-NUS Graduate Medical School Singapore, 8 College Road, Singapore, 169857, Singapore
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93
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Yien YY, Ducamp S, van der Vorm LN, Kardon JR, Manceau H, Kannengiesser C, Bergonia HA, Kafina MD, Karim Z, Gouya L, Baker TA, Puy H, Phillips JD, Nicolas G, Paw BH. 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 PMCID: PMC5617249 DOI: 10.1073/pnas.1700632114] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [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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Affiliation(s)
- Yvette Y Yien
- Division of Hematology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Sarah Ducamp
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, 75018 Paris, France
- Assistance Publique-Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, 92701 Colombes Cedex, France
- Laboratory of Excellence, GR-Ex, 75015 Paris, France
| | - Lisa N van der Vorm
- Division of Hematology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Julia R Kardon
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Hana Manceau
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, 75018 Paris, France
- Assistance Publique-Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, 92701 Colombes Cedex, France
- Laboratory of Excellence, GR-Ex, 75015 Paris, France
| | - Caroline Kannengiesser
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, 75018 Paris, France
- Laboratory of Excellence, GR-Ex, 75015 Paris, France
- Département de Génétique, Assistance Publique-Hôpitaux de Paris, HUPNVS, Hôpital Bichat, 75877 Paris Cedex, France
| | - Hector A Bergonia
- Division of Hematology, University of Utah School of Medicine, Salt Lake City, UT 84112
| | - Martin D Kafina
- Division of Hematology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115
| | - Zoubida Karim
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, 75018 Paris, France
- Assistance Publique-Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, 92701 Colombes Cedex, France
- Laboratory of Excellence, GR-Ex, 75015 Paris, France
| | - Laurent Gouya
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, 75018 Paris, France
- Assistance Publique-Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, 92701 Colombes Cedex, France
- Laboratory of Excellence, GR-Ex, 75015 Paris, France
| | - Tania A Baker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139;
- Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139
| | - Hervé Puy
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, 75018 Paris, France;
- Assistance Publique-Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, 92701 Colombes Cedex, France
- Laboratory of Excellence, GR-Ex, 75015 Paris, France
| | - John D Phillips
- Division of Hematology, University of Utah School of Medicine, Salt Lake City, UT 84112;
| | - Gaël Nicolas
- INSERM U1149, CNRS ERL 8252, Centre de Recherche sur l'inflammation, Université Paris Diderot, Site Bichat, Sorbonne Paris Cité, 75018 Paris, France
- Assistance Publique-Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, 92701 Colombes Cedex, France
- Laboratory of Excellence, GR-Ex, 75015 Paris, France
| | - Barry H Paw
- Division of Hematology, Brigham & Women's Hospital, Harvard Medical School, Boston, MA 02115;
- Division of Hematology-Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA 02115
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94
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Affiliation(s)
- D Montgomery Bissell
- From the Department of Medicine, Division of Gastroenterology and Porphyria Center, University of California, San Francisco, San Francisco (D.M.B.); the Departments of Preventive Medicine and Community Health and Internal Medicine, Division of Gastroenterology and Hepatology, University of Texas Medical Branch, Galveston (K.E.A.); and the Department of Gastroenterology, Wake Forest School of Medicine, Winston-Salem, NC (H.L.B.)
| | - Karl E Anderson
- From the Department of Medicine, Division of Gastroenterology and Porphyria Center, University of California, San Francisco, San Francisco (D.M.B.); the Departments of Preventive Medicine and Community Health and Internal Medicine, Division of Gastroenterology and Hepatology, University of Texas Medical Branch, Galveston (K.E.A.); and the Department of Gastroenterology, Wake Forest School of Medicine, Winston-Salem, NC (H.L.B.)
| | - Herbert L Bonkovsky
- From the Department of Medicine, Division of Gastroenterology and Porphyria Center, University of California, San Francisco, San Francisco (D.M.B.); the Departments of Preventive Medicine and Community Health and Internal Medicine, Division of Gastroenterology and Hepatology, University of Texas Medical Branch, Galveston (K.E.A.); and the Department of Gastroenterology, Wake Forest School of Medicine, Winston-Salem, NC (H.L.B.)
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95
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Balwani M, Naik H, Anderson KE, Bissell DM, Bloomer J, Bonkovsky HL, Phillips JD, Overbey JR, Wang B, Singal AK, Liu LU, Desnick RJ. Clinical, Biochemical, and Genetic Characterization of North American Patients With Erythropoietic Protoporphyria and X-linked Protoporphyria. JAMA Dermatol 2017; 153:789-796. [PMID: 28614581 DOI: 10.1001/jamadermatol.2017.1557] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Importance Autosomal recessive erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) are rare photodermatoses presenting with variable degrees of painful phototoxicity that markedly affects quality of life. The clinical variability, determinants of severity, and genotype/phenotype correlations of these diseases are not well characterized. Objective To describe the baseline clinical characteristics, genotypes, and determinants of disease severity in a large patient cohort with EPP or XLP. Design, Setting, and Participants A prospective observational study was conducted among patients with confirmed diagnoses of EPP or XLP from November 1, 2010, to December 6, 2015, at 6 academic medical centers of the Porphyrias Consortium of the National Institutes of Health Rare Diseases Clinical Research Network. Detailed medical histories, including history of phototoxicity and treatment, were collected on standardized case report forms. Patients underwent baseline laboratory testing, total erythrocyte protoporphyrin (ePPIX) testing, and molecular genetic testing. Data were entered into a centralized database. Main Outcomes and Measures Results of biochemical and genetic tests were explored for association with clinical phenotype in patients with EPP or XLP. Results Of the 226 patients in the study (113 female and 113 male patients; mean [SD] age, 36.7 [17.0] years), 186 (82.3%) had EPP with a FECH (OMIM 612386) mutation and the common low-expression FECH allele IVS3-48T>C, and only 1 patient had 2 FECH mutations. Twenty-two patients had XLP (9.7%; 10 male and 12 female patients), and 9 patients (4.0%) had elevated ePPIX levels and symptoms consistent with protoporphyria but no detectable mutation in the FECH or ALAS2 (OMIM 301300) gene. Samples of DNA could not be obtained from 8 patients. Patients' mean (SD) age at symptom onset was 4.4 (4.4) years. Anemia (107 [47.3%]), history of liver dysfunction (62 [27.4%]), and gallstones (53 [23.5%]) were commonly reported. Higher ePPIX levels were associated with earlier age of symptom onset (median ePPIX levels for those who developed symptoms before vs after 1 year of age, 1744 vs 1567 µg/dL; P = .02), less sun tolerance (median ePPIX levels for those reporting symptoms before vs after 10 minutes of sun exposure, 2233 vs 1524 µg/dL; P ≤ .001), and increased risk of liver dysfunction (median ePPIX levels for those with liver dysfunction vs normal liver function, 2016 vs 1510 µg/dL; P = .003). Patients with EPP and FECH missense mutations had significantly lower ePPIX levels than those with other mutations (1462 vs 1702 µg/dL; P = .01). Male patients with XLP had significantly higher ePPIX levels, on average, than did patients with EPP (3574 vs 1669 µg/dL; P < .001). Marked clinical variability was seen in female patients with XLP owing to random X-chromosomal inactivation. Conclusions and Relevance These data suggest that higher ePPIX levels are a major determinant of disease severity and risk of liver dysfunction in patients with EPP or XLP. These findings provide a framework for clinical monitoring and management of these disorders.
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Affiliation(s)
- Manisha Balwani
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York
| | - Hetanshi Naik
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York
| | - Karl E Anderson
- Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston
| | | | - Joseph Bloomer
- Department of Medicine, University of Alabama, Birmingham
| | - Herbert L Bonkovsky
- Department of Medicine, Wake Forest Baptist Medical Center, Winston-Salem, North Carolina
| | - John D Phillips
- Department of Internal Medicine, University of Utah, Salt Lake City
| | - Jessica R Overbey
- Department of Population Health Science and Policy, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Bruce Wang
- Department of Medicine, University of California, San Francisco
| | | | - Lawrence U Liu
- Department of Liver Diseases and Recanti/Miller Transplantation Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Robert J Desnick
- Department of Genetics and Genomic Sciences, Mount Sinai School of Medicine, New York, New York
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96
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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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97
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Fratz-Berilla EJ, Breydo L, Gouya L, Puy H, Uversky VN, Ferreira GC. Isoniazid inhibits human erythroid 5-aminolevulinate synthase: Molecular mechanism and tolerance study with four X-linked protoporphyria patients. Biochim Biophys Acta Mol Basis Dis 2017; 1863:428-439. [DOI: 10.1016/j.bbadis.2016.11.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Revised: 10/19/2016] [Accepted: 11/08/2016] [Indexed: 10/20/2022]
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98
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Na I, DeForte S, Stojanovski BM, Ferreira GC, Uversky VN. Molecular dynamics analysis of the structural and dynamic properties of the functionally enhanced hepta-variant of mouse 5-aminolevulinate synthase. J Biomol Struct Dyn 2017; 36:152-165. [PMID: 27928941 DOI: 10.1080/07391102.2016.1269688] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Heme biosynthesis, a complex, multistage, and tightly controlled process, starts with 5-aminolevulinate (ALA) production, which, in metazoa and certain bacteria, is a reaction catalyzed by 5-aminolevulinate synthase (ALAS), a pyridoxal 5'-phosphate (PLP)-dependent enzyme. Functional aberrations in ALAS are associated with several human diseases. ALAS can adopt open and closed conformations, with segmental rearrangements of a C-terminal, 16-amino acid loop and an α-helix regulating accessibility to the ALAS active site. Of the murine erythroid ALAS (mALAS2) forms previously engineered to assess the role of the flexible C-terminal loop versus mALAS2 function one stood out due to its impressive gain in catalytic power. To elucidate how the simultaneously introduced seven mutations of this activity-enhanced variant affected structural and dynamic properties of mALAS2, we conducted extensive molecular dynamics simulation analysis of the dimeric forms of wild-type mALAS2, hepta-variant and Rhodobacter capsulatus ALAS (aka R. capsulatus HemA). This analysis revealed that the seven simultaneous mutations in the C-terminal loop, which extends over the active site of the enzyme, caused the bacterial and murine proteins to adopt different conformations. Specifically, a new β-strand in the mutated 'loop' led to interaction with two preexisting β-strands and formation of an anti-parallel three-stranded β-sheet, which likely endowed the murine hepta-variant a more 'stable' open conformation than that of wild-type mALAS2, consistent with a kinetic mechanism involving a faster closed-to-open conformation transition and product release for the mutated than wild-type enzyme. Further, the dynamic behavior of the mALAS2 protomers was strikingly different in the two dimeric forms.
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Affiliation(s)
- Insung Na
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Shelly DeForte
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Bosko M Stojanovski
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA
| | - Gloria C Ferreira
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA.,b Department of Chemistry , College of Arts and Sciences, University of South Florida , Tampa , FL 33612 , USA
| | - Vladimir N Uversky
- a Department of Molecular Medicine , Morsani College of Medicine, University of South Florida , Tampa , FL 33612 , USA.,c USF Health Byrd Alzheimer's Research Institute, Morsani College of Medicine , University of South Florida , Tampa , Florida 33612 , USA.,d Laboratory of Structural Dynamics, Stability and Folding of Proteins , Institute of Cytology, Russian Academy of Sciences , St. Petersburg , Russia
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99
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Kürten V, Neumann NJ, Frank J. [Diagnosis of the porphyrias : From A (as in aminolevulinic acid) to Z (as in zinc protoporphyrin)]. Hautarzt 2016; 67:201-6. [PMID: 26743052 DOI: 10.1007/s00105-015-3741-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The porphyrias comprise a clinically, biochemically, and genetically heterogeneous group of predominantly hereditary metabolic disorders resulting from a dysfunction along the heme biosynthetic pathway. Whereas most variants can manifest with different cutaneous symptoms, some types only reveal life-threatening acute neurovisceral attacks. Therefore, interdisciplinary care of these patients is advisable. In this article, we provide an overview of characteristic clinical and laboratory findings in the various forms of porphyria and a diagnostic algorithm.
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Affiliation(s)
- V Kürten
- Hautklinik und Europäisches Porphyriezentrum, Universitätsklinikum der Heinrich-Heine-Universität Düsseldorf, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - N J Neumann
- Hautklinik und Europäisches Porphyriezentrum, Universitätsklinikum der Heinrich-Heine-Universität Düsseldorf, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland
| | - J Frank
- Hautklinik und Europäisches Porphyriezentrum, Universitätsklinikum der Heinrich-Heine-Universität Düsseldorf, Universitätsklinikum Düsseldorf, Moorenstr. 5, 40225, Düsseldorf, Deutschland.
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100
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Long ZB, Wang YW, Yang C, Liu G, Du YL, Nie GJ, Chang YZ, Han B. Identification of FECH gene multiple variations in two Chinese patients with erythropoietic protoporphyria and a review. J Zhejiang Univ Sci B 2016; 17:813-820. [PMID: 27704751 DOI: 10.1631/jzus.b1600085] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Erythropoietic protoporphyria (EPP), an autosomal dominant disease, is caused by partial deficiency of ferrochelatase (FECH), which catalyzes the terminal step of heme biosynthesis because of loss-of-function mutations in the FECH gene. To date, only a few cases have been described in Asia. In this study, we describe the clinical features of two Chinese patients with EPP, with diagnosis confirmed by the increase of free protoporphyrin in erythrocytes, detection of plasma fluorescence peak at 630-634 nm, and analysis of FECH gene mutations. Using gene scanning, we identified a small deletion in the FECH gene (c.973 delA) in one proband (patient A) and a pathogenic FECH mutation (c.1232 G>T) in the other (patient B) and also observed some nucleotide variations (c.798 C>G, c.921 A>G, IVS1-23 C>T, IVS3+23 A>G, IVS9+35 C>T, and IVS3-48 T>C) in these patients. The family pedigree of patient A was then established by characterization of the genotype of the patient's relatives. We also analyzed the potential perniciousness of the missense mutation with bioinformatic software, Polyphen and Sift. In summary, Chinese EPP patients have similar manifestations to those of Caucasians, and identification of the Chinese FECH gene mutations expands the FECH genotypic spectrum and may contribute to genetic counseling.
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Affiliation(s)
- Zhang-Biao Long
- Department of Hematology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Yong-Wei Wang
- Laboratory of Molecular Iron Metabolism, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China.,Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190, China
| | - Chen Yang
- Department of Hematology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Gang Liu
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190, China
| | - Ya-Li Du
- Department of Hematology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
| | - Guang-Jun Nie
- Chinese Academy of Sciences Key Laboratory for Biomedical Effects of Nanomaterials and Nanosafety, National Center for Nanoscience and Technology, Beijing 100190, China
| | - Yan-Zhong Chang
- Laboratory of Molecular Iron Metabolism, College of Life Science, Hebei Normal University, Shijiazhuang 050024, China
| | - Bing Han
- Department of Hematology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China
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