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Di Candia F, Di Iorio V, Tinto N, Bonfanti R, Iovino C, Rosanio FM, Fedi L, Iafusco F, Arrigoni F, Malesci R, Simonelli F, Rigamonti A, Franzese A, Mozzillo E. An Italian case series' description of thiamine responsive megaloblastic anemia syndrome: importance of early diagnosis and treatment. Ital J Pediatr 2023; 49:158. [PMID: 38037112 PMCID: PMC10691017 DOI: 10.1186/s13052-023-01553-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 09/12/2023] [Indexed: 12/02/2023] Open
Abstract
BACKGROUND Individuals with thiamine-responsive megaloblastic anemia (TRMA) mainly manifest macrocytic anemia, sensorineural deafness, ocular complications, and nonautoimmune diabetes. Macrocytic anemia and diabetes may be responsive to high-dosage thiamine treatment, in contrast to sensorineural deafness. Little is known about the efficacy of thiamine treatment on ocular manifestations. CASES PRESENTATION Our objective is to report data from four Italian TRMA patients: in Cases 1, 2 and 3, the diagnosis of TRMA was made at 9, 14 and 27 months. In 3 out of 4 subjects, thiamine therapy allowed both normalization of hyperglycemia, with consequent insulin suspension, and macrocytic anemia. In all Cases, thiamine therapy did not resolve the clinical manifestation of deafness. In Cases 2 and 3, follow-up showed no blindness, unlike Case 4, in which treatment was started for megaloblastic anemia at age 7 but was increased to high doses only at age 25, when the genetic diagnosis of TRMA was performed. CONCLUSIONS Early institution of high-dose thiamine supplementation seems to prevent the development of retinal changes and optic atrophy in TRMA patients. The spectrum of clinical manifestations is broad, and it is important to describe known Cases to gain a better understanding of this rare disease.
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Affiliation(s)
- Francesca Di Candia
- Department of Translational Medical Science, Section of Pediatrics, Regional Centre of Pediatric Diabetes, Federico II University of Naples, Via S. Pansini 5, Naples, 80131, Italy
| | - Valentina Di Iorio
- Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Nadia Tinto
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
- CEINGE Advanced Biotechnology, Naples, Italy
| | - Riccardo Bonfanti
- Department of Pediatrics, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy
- Vita Salute San Raffaele University, Milan, Italy
| | - Claudio Iovino
- Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Francesco Maria Rosanio
- Department of Translational Medical Science, Section of Pediatrics, Regional Centre of Pediatric Diabetes, Federico II University of Naples, Via S. Pansini 5, Naples, 80131, Italy
| | - Ludovica Fedi
- Department of Translational Medical Science, Section of Pediatrics, Regional Centre of Pediatric Diabetes, Federico II University of Naples, Via S. Pansini 5, Naples, 80131, Italy
| | - Fernanda Iafusco
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy
| | - Francesca Arrigoni
- Department of Pediatrics, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Rita Malesci
- Unit of Audiology, Department of Neurosciences, Reproductives and Odontostomatologic Sciences, University of Naples ''Federico II'', Naples, Italy
| | - Francesca Simonelli
- Multidisciplinary Department of Medical, Surgical and Dental Sciences, Eye Clinic, University of Campania Luigi Vanvitelli, Naples, Italy
| | - Andrea Rigamonti
- Department of Pediatrics, Diabetes Research Institute, IRCCS Ospedale San Raffaele, Milan, Italy
| | - Adriana Franzese
- Department of Translational Medical Science, Section of Pediatrics, Regional Centre of Pediatric Diabetes, Federico II University of Naples, Via S. Pansini 5, Naples, 80131, Italy
| | - Enza Mozzillo
- Department of Translational Medical Science, Section of Pediatrics, Regional Centre of Pediatric Diabetes, Federico II University of Naples, Via S. Pansini 5, Naples, 80131, Italy.
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Kang P, Zhang W, Wen J, Zhang J, Li F, Sun W. Case Report: Genetic and Clinical Features of Maternal Uniparental Isodisomy-Induced Thiamine-Responsive Megaloblastic Anemia Syndrome. Front Pediatr 2021; 9:630329. [PMID: 33816400 PMCID: PMC8017196 DOI: 10.3389/fped.2021.630329] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Accepted: 02/16/2021] [Indexed: 01/19/2023] Open
Abstract
Background: Thiamine-responsive megaloblastic anemia syndrome (TRMA) is a rare autosomal recessive hereditary disease due to mutations in SLC19A2. Some cases show familial inheritance. Case report: A female patient (from a gravida 1, para 1 mother) of 3.5 years of age was admitted to the Pediatric Hematology Department of Xianyang Caihong Hospital in June 2019. The patient had severe anemia, acupoint-size bleeding spots, and a few ecchymoses all over her body, as well as astigmatism and hyperopia. Hearing was normal. The patient had diabetes. Bone marrow biopsy suggested a myelodysplastic syndrome. The patient had a c.515G>A (p.G172D) homozygous mutation of SLC19A2 (NM_006996), indicating TRMA. Genetic testing revealed that the two alleles were inherited from her mother alone due to maternal uniparental isodisomy (UPD). The patient was treated with thiamine and a subcutaneous injection of insulin. The patient recovered well and was discharged. She continued thiamine and insulin at the same dose and was followed once a month. The last follow-up on September 15, 2020, showed no anemia or bleeding. She had a sound hearing and normal blood routine and fasting glucose levels. Hyperopia and astigmatism did not improve. Conclusion: The patient had TRMA induced by the c.515G>A (p.G172D) homozygous mutation of SLC19A2 inherited through maternal UPD. The genetic diagnosis of TRMA is of significance for guiding clinical treatment. Early treatment with exogenous thiamine can improve some of the clinical features of TRMA.
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Affiliation(s)
| | | | | | | | - Fei Li
- Caihong Hospital, Xianyang, China
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3
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Faraji‐Goodarzi M, Tarhani F, Taee N. Dyserythropoiesis and myelodysplasia in thiamine-responsive megaloblastic anemia syndrome. Clin Case Rep 2020; 8:991-994. [PMID: 32577249 PMCID: PMC7303871 DOI: 10.1002/ccr3.2791] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 02/04/2020] [Accepted: 02/11/2020] [Indexed: 01/19/2023] Open
Abstract
The case of thiamine-responsive megaloblastic anemia (TRMA) presented here speculates the need early diagnosis, continuous monitoring, follow-up, and regulated treatment plan for the patients. Complications and systemic manifestations are likely to enhance in otherwise circumstances.
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Affiliation(s)
- Mojgan Faraji‐Goodarzi
- Department of PediatricsFaculty of MedicineLorestan University of Medical SciencesKhorramabadIran
| | - Fariba Tarhani
- Department of PediatricsFaculty of MedicineLorestan University of Medical SciencesKhorramabadIran
| | - Nadereh Taee
- Department of PediatricsFaculty of MedicineLorestan University of Medical SciencesKhorramabadIran
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4
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Fan Y, Qin Y, Chen M, Li X, Wang R, Huang Z, Xu Q, Yu M, Zhang Y, Han X, Du G, Xia Y, Wang X, Lu C. Prenatal low-dose DEHP exposure induces metabolic adaptation and obesity: Role of hepatic thiamine metabolism. JOURNAL OF HAZARDOUS MATERIALS 2020; 385:121534. [PMID: 31706747 PMCID: PMC7220048 DOI: 10.1016/j.jhazmat.2019.121534] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Revised: 10/10/2019] [Accepted: 10/23/2019] [Indexed: 05/04/2023]
Abstract
Di-(2-ethylhexyl)-phthalate (DEHP) is a ubiquitous environmental pollutant and is widely used in industrial plastics. However, the long-term health implications of prenatal exposure to DEHP remains unclear. We set out to determine whether prenatal DEHP exposure can induce metabolic syndrome in offspring and investigate the underlying mechanisms. A mouse model of prenatal DEHP exposure (0.2, 2, and 20 mg/kg/day) was established to evaluate the long-term metabolic disturbance in offspring. The mice were profiled for the hepatic metabolome, transcriptome and gut microbiota to determine the underlying mechanisms. Thiamine supplementation (50 mg/kg/day) was administered to offspring to investigate the role of thiamine in ameliorating metabolic syndrome. Prenatal exposure to low-dose DEHP (0.2 mg/kg/day) resulted in metabolic syndrome, including abnormal adipogenesis, energy expenditure and glucose metabolism, along with dysbiosis of the gut microbiome, in male offspring. Notably, hepatic thiamine metabolism was disrupted in these offspring due to the dysregulation of thiamine transport enzymes, which caused abnormal glucose metabolism. Prenatal low-dose DEHP exposure caused life-long metabolic consequences in a sex-dependent manner, and these consequences were be attenuated by thiamine supplementation in offspring. Our findings suggest low-dose DEHP exposure during early life stages is a potential risk factor for later obesity and metabolic syndrome.
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Affiliation(s)
- Yun Fan
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Yufeng Qin
- Epigenetics & Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, NC, 27709, USA
| | - Minjian Chen
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Xiuzhu Li
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Ruohan Wang
- The First Clinical Medical College of Nanjing Medical University, Nanjing 211166, China
| | - Zhenyao Huang
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Qiaoqiao Xu
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Mingming Yu
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Yan Zhang
- Kangda College of Nanjing Medical University, Lianyungang 222002, China
| | - Xiumei Han
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Guizhen Du
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Yankai Xia
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China
| | - Xinru Wang
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
| | - Chuncheng Lu
- State Key Laboratory of Reproductive Medicine, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing 211166, China.
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Tsui E, Tauber J, Barbazetto I, Gelman SK. LONG-TERM MULTIMODAL IMAGING OF OCULAR FINDINGS ASSOCIATED WITH THIAMINE-RESPONSIVE MEGALOBLASTIC ANEMIA. Retin Cases Brief Rep 2020; 14:247-250. [PMID: 29210962 DOI: 10.1097/icb.0000000000000686] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
PURPOSE To report on 5-year multimodal imaging of ocular findings in a patient with thiamine-responsive megaloblastic anemia. METHODS Observational case report. RESULTS A 20-year-old-man with a history of thiamine-responsive megaloblastic anemia demonstrated a symmetric bull's eye maculopathy. Spectral domain optical coherence tomography revealed disruption of the parafoveal ellipsoid zone, fundus autofluorescence demonstrated foveal hypoautofluorescence, and full-field electroretinogram testing revealed a decreased photopic and scotopic response consistent with cone-rod dystrophy. His best-corrected visual acuity remained stable over 5 years at 20/50 in the right eye and 20/40 in the left eye, and visual field testing remained stable over time. CONCLUSION Ocular manifestations in thiamine-responsive megaloblastic anemia are uncommon and variable. In this case, multimodal imaging and electroretinogram findings are consistent with cone-rod degeneration. The patient is taking daily thiamine supplementation, and visual acuity, funduscopic examination, spectral domain optical coherence tomography, and autofluorescence remained stable over a 5-year period.
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Affiliation(s)
- Edmund Tsui
- Department of Ophthalmology, New York University School of Medicine, New York, New York
| | - Jenna Tauber
- Department of Ophthalmology, New York University School of Medicine, New York, New York
| | - Irene Barbazetto
- Department of Ophthalmology, New York University School of Medicine, New York, New York
- Vitreous Retinal Macula Consultants of New York, New York, New York; and
| | - Susan K Gelman
- Department of Ophthalmology, New York University School of Medicine, New York, New York
- Retina Specialists, P.C., New York, New York
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Dalwadi P, Joshi AS, Thakur DS, Bhagwat NM. Neonatal diabetes mellitus: remission induced by novel therapy. BMJ Case Rep 2019; 12:12/6/e228806. [PMID: 31243025 DOI: 10.1136/bcr-2018-228806] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
A female child with deafness was diagnosed to have neonatal diabetes mellitus at the age of 6 months, on routine evaluation prior to cochlear implant surgery. She presented to us at 11 months of age with diabetic ketoacidosis due to an intercurrent febrile illness. Her haematological parameters showed megaloblastic anaemia and thrombocytopenia. Therefore a possibility of Thiamine Responsive Megaloblastic Anaemia (TRMA) syndrome was considered. She was empirically treated with parenteral thiamine hydrochloride (Hcl). Subsequently, due to the unavailability of pharmacological preparation of oral thiamine Hcl in a recommended dose she was treated with benfotiamine. She had a sustained improvement in all her haematological parameters on oral benfotiamine. The insulin requirement progressively reduced and she is currently in remission for last 2 years. The genetic analysis confirmed the diagnosis of TRMA syndrome. Thus benfotiamine can be considered a new treatment option in management of TRMA syndrome.
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Affiliation(s)
- Pradip Dalwadi
- Endocrinology, Topiwala National Medical College and BYL Nair Charitable Hospital, Mumbai, Maharashtra, India
| | - Ameya S Joshi
- Endocrinology, Topiwala National Medical College and BYL Nair Charitable Hospital, Mumbai, Maharashtra, India
| | - Darshana Sudip Thakur
- Endocrinology, Topiwala National Medical College and BYL Nair Charitable Hospital, Mumbai, Maharashtra, India
| | - Nikhil M Bhagwat
- Endocrinology, Topiwala National Medical College and BYL Nair Charitable Hospital, Mumbai, Maharashtra, India
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7
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Ion Transporters, Channelopathies, and Glucose Disorders. Int J Mol Sci 2019; 20:ijms20102590. [PMID: 31137773 PMCID: PMC6566632 DOI: 10.3390/ijms20102590] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 01/19/2023] Open
Abstract
Ion channels and transporters play essential roles in excitable cells including cardiac, skeletal and smooth muscle cells, neurons, and endocrine cells. In pancreatic beta-cells, for example, potassium KATP channels link the metabolic signals generated inside the cell to changes in the beta-cell membrane potential, and ultimately regulate insulin secretion. Mutations in the genes encoding some ion transporter and channel proteins lead to disorders of glucose homeostasis (hyperinsulinaemic hypoglycaemia and different forms of diabetes mellitus). Pancreatic KATP, Non-KATP, and some calcium channelopathies and MCT1 transporter defects can lead to various forms of hyperinsulinaemic hypoglycaemia (HH). Mutations in the genes encoding the pancreatic KATP channels can also lead to different types of diabetes (including neonatal diabetes mellitus (NDM) and Maturity Onset Diabetes of the Young, MODY), and defects in the solute carrier family 2 member 2 (SLC2A2) leads to diabetes mellitus as part of the Fanconi–Bickel syndrome. Variants or polymorphisms in some ion channel genes and transporters have been reported in association with type 2 diabetes mellitus.
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Habeb AM, Flanagan SE, Zulali MA, Abdullah MA, Pomahačová R, Boyadzhiev V, Colindres LE, Godoy GV, Vasanthi T, Al Saif R, Setoodeh A, Haghighi A, Haghighi A, Shaalan Y, Hattersley AT, Ellard S, De Franco E. Pharmacogenomics in diabetes: outcomes of thiamine therapy in TRMA syndrome. Diabetologia 2018; 61:1027-1036. [PMID: 29450569 PMCID: PMC6449001 DOI: 10.1007/s00125-018-4554-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Accepted: 12/07/2017] [Indexed: 02/06/2023]
Abstract
AIMS/HYPOTHESIS Diabetes is one of the cardinal features of thiamine-responsive megaloblastic anaemia (TRMA) syndrome. Current knowledge of this rare monogenic diabetes subtype is limited. We investigated the genotype, phenotype and response to thiamine (vitamin B1) in a cohort of individuals with TRMA-related diabetes. METHODS We studied 32 individuals with biallelic SLC19A2 mutations identified by Sanger or next generation sequencing. Clinical details were collected through a follow-up questionnaire. RESULTS We identified 24 different mutations, of which nine are novel. The onset of the first TRMA symptom ranged from birth to 4 years (median 6 months [interquartile range, IQR 3-24]) and median age at diabetes onset was 10 months (IQR 5-27). At presentation, three individuals had isolated diabetes and 12 had asymptomatic hyperglycaemia. Follow-up data was available for 15 individuals treated with thiamine for a median 4.7 years (IQR 3-10). Four patients were able to stop insulin and seven achieved better glycaemic control on lower insulin doses. These 11 patients were significantly younger at diabetes diagnosis (p = 0.042), at genetic testing (p = 0.01) and when starting thiamine (p = 0.007) compared with the rest of the cohort. All patients treated with thiamine became transfusion-independent and adolescents achieved normal puberty. There were no additional benefits of thiamine doses >150 mg/day and no reported side effects up to 300 mg/day. CONCLUSIONS/INTERPRETATION In TRMA syndrome, diabetes can be asymptomatic and present before the appearance of other features. Prompt recognition is essential as early treatment with thiamine can result in improved glycaemic control, with some individuals becoming insulin-independent. DATA AVAILABILITY SLC19A2 mutation details have been deposited in the Decipher database ( https://decipher.sanger.ac.uk/ ).
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Affiliation(s)
- Abdelhadi M Habeb
- Paediatric Department, Prince Mohammed bin Abdulaziz Hospital, National Guard Ministry, P.O. Box 40740, Al Madinah, 41511, Kingdom of Saudi Arabia.
| | - Sarah E Flanagan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Royal Devon and Exeter Hospital, Barrack Road, Exeter, EX2 5DW, UK
| | - Mohamed A Zulali
- Paediatric Department, College of Medicine, Taibah University, Madinah, Kingdom of Saudi Arabia
| | | | - Renata Pomahačová
- Department of Paediatrics, Charles University, Medical Faculty and University Hospital Pilsen, Pilsen, Czech Republic
| | | | | | | | | | - Ramlah Al Saif
- Paediatric Department, Maternity and Children's Hospital, Dammam, Kingdom of Saudi Arabia
| | - Aria Setoodeh
- Growth & Development Research Centre, University of Tehran, Medical Sciences, Tehran, Iran
| | - Amirreza Haghighi
- Toronto General Hospital, University of Toronto, Toronto, ON, Canada
| | - Alireza Haghighi
- Department of Genetics and Medicine, Harvard Medical School, Boston, MA, USA
- Broad Institutes of Harvard and MIT, Cambridge, MA, USA
- Partners HealthCare Laboratory for Molecular Medicine, Cambridge, MA, USA
| | | | - Andrew T Hattersley
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Royal Devon and Exeter Hospital, Barrack Road, Exeter, EX2 5DW, UK
| | - Sian Ellard
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Royal Devon and Exeter Hospital, Barrack Road, Exeter, EX2 5DW, UK
| | - Elisa De Franco
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Royal Devon and Exeter Hospital, Barrack Road, Exeter, EX2 5DW, UK.
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Ortigoza-Escobar JD, Molero-Luis M, Arias A, Martí-Sánchez L, Rodriguez-Pombo P, Artuch R, Pérez-Dueñas B. Treatment of genetic defects of thiamine transport and metabolism. Expert Rev Neurother 2016; 16:755-63. [DOI: 10.1080/14737175.2016.1187562] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- Juan Darío Ortigoza-Escobar
- Department of Child Neurology, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
- Department of Child Neurology, Hospital General de Granollers, Barcelona, Spain
| | - Marta Molero-Luis
- Clinical Biochemistry, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
- Centre for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Angela Arias
- Division of Inborn Errors of Metabolism-IBC, Department of Biochemistry and Molecular Genetics, Hospital Clinic, Barcelona, Spain
- Centre for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Laura Martí-Sánchez
- Department of Child Neurology, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
- Clinical Biochemistry, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
| | - Pilar Rodriguez-Pombo
- Departamento de Biología Molecular, Centro de Diagnóstico de Enfermedades Moleculares (CEDEM), Centro de Biología Molecular Severo Ochoa CSIC-UAM, IDIPAZ, Universidad Autónoma de Madrid, Madrid, Spain
- Centre for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Rafael Artuch
- Clinical Biochemistry, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
- Centre for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Belén Pérez-Dueñas
- Department of Child Neurology, Hospital Sant Joan de Déu, University of Barcelona, Barcelona, Spain
- Centre for the Biomedical Research on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
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10
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Manimaran P, Subramanian VS, Karthi S, Gandhimathi K, Varalakshmi P, Ganesh R, Rathinavel A, Said HM, Ashokkumar B. Novel nonsense mutation (p.Ile411Metfs*12) in the SLC19A2 gene causing Thiamine Responsive Megaloblastic Anemia in an Indian patient. Clin Chim Acta 2015; 452:44-9. [PMID: 26549656 DOI: 10.1016/j.cca.2015.11.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 11/02/2015] [Accepted: 11/04/2015] [Indexed: 01/19/2023]
Abstract
Thiamine-responsive megaloblastic anemia (TRMA), an autosomal recessive disorder, is caused by mutations in SLC19A2 gene encodes a high affinity thiamine transporter (THTR-1). The occurrence of TRMA is diagnosed by megaloblastic anemia, diabetes mellitus, and sensorineural deafness. Here, we report a female TRMA patient of Indian descent born to 4th degree consanguineous parents presented with retinitis pigmentosa and vision impairment, who had a novel homozygous mutation (c.1232delT/ter422; p.Ile411Metfs*12) in 5th exon of SLC19A2 gene that causes premature termination of hTHTR-1. PROSITE analysis predicted to abrogate GPCRs family-1 signature motif in the variant by this mutation c.1232delT/ter422, suggesting uncharacteristic rhodopsin function leading to cause RP clinically. Thiamine transport activity by the clinical variant was severely inhibited than wild-type THTR-1. Confocal imaging had shown that the variant p.I411Mfs*12 is targeted to the cell membrane and showed no discrepancy in membrane expression than wild-type. Our findings are the first report, to the best of our knowledge, on this novel nonsense mutation of hTHTR-1 causing TRMA in an Indian patient through functionally impaired thiamine transporter activity.
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Affiliation(s)
| | - Veedamali S Subramanian
- Departments of Medicine, Physiology/Biophysics, University of California, Irvine, CA; Department of Veterans Affairs Medical Center, Long Beach, CA 90822, USA
| | - Sellamuthu Karthi
- School of Biotechnology, Madurai Kamaraj University, Madurai 625 021, India
| | | | | | - Ramasamy Ganesh
- Kanchi Kamakoti CHILDS Trust Hospital, Nungambakkam, Chennai 600 034, India
| | - Andiappan Rathinavel
- Department of Cardiothoracic Surgery, Madurai Medical College, Madurai 625 020, India
| | - Hamid M Said
- Departments of Medicine, Physiology/Biophysics, University of California, Irvine, CA; Department of Veterans Affairs Medical Center, Long Beach, CA 90822, USA
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A novel homozygous SLC19A2 mutation in a Portuguese patient with diabetes mellitus and thiamine-responsive megaloblastic anaemia. INTERNATIONAL JOURNAL OF PEDIATRIC ENDOCRINOLOGY 2015; 2015:6. [PMID: 25878670 PMCID: PMC4397709 DOI: 10.1186/s13633-015-0002-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/13/2014] [Accepted: 01/19/2015] [Indexed: 01/19/2023]
Abstract
Thiamine-responsive megaloblastic anaemia (TRMA) is a rare syndrome where patients present with early onset diabetes mellitus, megaloblastic anaemia and sensorineural deafness. This report describes a new case of TRMA syndrome in a female patient of Portuguese descent, born to unrelated parents. The patient was found to have a novel homozygous change R397X in exon 4 of the SLC19A2 gene, leading to a premature stop codon. The patient’s diabetes and anaemia showed a good response to daily thiamine doses, reducing the daily insulin dose requirement. The report further indicates that TRMA is not only limited to consanguineous or ethnically isolated families, and should be considered as a differential diagnosis for patients presenting with suggestive clinical symptoms.
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Mikstiene V, Songailiene J, Byckova J, Rutkauskiene G, Jasinskiene E, Verkauskiene R, Lesinskas E, Utkus A. Thiamine responsive megaloblastic anemia syndrome: A novel homozygousSLC19A2gene mutation identified. Am J Med Genet A 2015; 167:1605-9. [DOI: 10.1002/ajmg.a.37015] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 01/19/2015] [Indexed: 01/19/2023]
Affiliation(s)
- Violeta Mikstiene
- Department of Human and Medical Genetics, Faculty of Medicine; Vilnius University; Vilnius Lithuania
| | - Jurgita Songailiene
- Department of Human and Medical Genetics, Faculty of Medicine; Vilnius University; Vilnius Lithuania
| | - Jekaterina Byckova
- Centre of Ear, Nose and Throat Diseases; Vilnius University Hospital Santariškių Clinics; Vilnius Lithuania
| | - Giedre Rutkauskiene
- Pediatric Oncology and Hematology Unit; Hospital of Lithuanian university of Health Sciences, Kaunas Clinics; Kaunas Lithuania
| | - Edita Jasinskiene
- Department of Endocrinology; Hospital of Lithuanian University of Health Science, Kaunas Clinics; Kaunas Lithuania
| | - Rasa Verkauskiene
- Department of Endocrinology; Hospital of Lithuanian University of Health Science, Kaunas Clinics; Kaunas Lithuania
| | - Eugenijus Lesinskas
- Centre of Ear, Nose and Throat Diseases; Vilnius University Hospital Santariškių Clinics; Vilnius Lithuania
| | - Algirdas Utkus
- Department of Human and Medical Genetics, Faculty of Medicine; Vilnius University; Vilnius Lithuania
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Abstract
Thiamine-responsive megaloblastic anemia syndrome is a rare autosomal recessive disorder defined by the occurrence of megaloblastic anemia, diabetes mellitus, and bilateral sensorineural deafness, responding in varying degrees to thiamine treatment. We report a precedence case for the treatment of deafness associated with the typical triad of thiamine-responsive megaloblastic anemia in a 4-year-old boy who showed a poor use of preoperative hearing aids but demonstrated significant improvements in hearing ability 1 year after receiving a cochlear implant.
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Affiliation(s)
- Abdulrahman Abdullah Hagr
- Dr. Abdulrahman Abdullah Hagr, ORL, King Agbdulaziz University Hospital,, PO Box 245, Riyadh 11411,, Saudi Arabia, T: +966505216261, F: +966114775735
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Srikrupa NN, Meenakshi S, Arokiasamy T, Murali K, Soumittra N. Leber’s Congenital Amaurosis as the Retinal Degenerative Phenotype in Thiamine Responsive Megaloblastic Anemia: A Case Report. Ophthalmic Genet 2013; 35:119-24. [DOI: 10.3109/13816810.2013.793363] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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15
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Disruption of thiamine uptake and growth of cells by feline leukemia virus subgroup A. J Virol 2012; 87:2412-9. [PMID: 23269813 DOI: 10.1128/jvi.03203-12] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Feline leukemia virus (FeLV) is still a major cause of morbidity and mortality in domestic cats and some wild cats despite the availability of relatively effective vaccines against the virus. FeLV subgroup A (FeLV-A) is transmitted in natural infections, and FeLV subgroups B, C, and T can evolve directly from FeLV-A by mutation and/or recombination with endogenous retroviruses in domestic cats, resulting in a variety of pathogenic outcomes. The cell surface entry receptor for FeLV-A is a putative thiamine transporter (THTR1). Here, we have addressed whether FeLV-A infection might disrupt thiamine uptake into cells and, because thiamine is an essential nutrient, whether this disruption might have pathological consequences. First, we cloned the cat ortholog of the other of the two known thiamine transporters in mammals, THTR2, and we show that feline THTR1 (feTHTR1) and feTHTR2 both mediate thiamine uptake, but feTHTR2 does not function as a receptor for FeLV-A. We found that feTHTR1 is widely expressed in cat tissues and in cell lines, while expression of feTHTR2 is restricted. Thiamine uptake mediated by feTHTR1 was indeed blocked by FeLV-A infection, and in feline fibroblasts that naturally express feTHTR1 and not feTHTR2, this blockade resulted in a growth arrest at physiological concentrations of extracellular thiamine. The growth arrest was reversed at high extracellular concentrations of thiamine. Our results show that FeLV-A infection can indeed disrupt thiamine uptake with pathological consequences. A prediction of these experiments is that raising the plasma levels of thiamine in FeLV-infected cats may ameliorate the pathogenic effects of infection.
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Ganie MA, Ali I, Ahangar AG, Wani MM, Ahmed S, Bhat MA, Seth S, Mudasir S. Thiamine responsive megaloblastic anemia syndrome associated with patent ductus arteriosus: First case report from Kashmir Valley of the Indian subcontinent. Indian J Endocrinol Metab 2012; 16:646-650. [PMID: 22837935 PMCID: PMC3401775 DOI: 10.4103/2230-8210.98033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Thiamine responsive megaloblastic anemia syndrome, an autosomal recessive inherited disorder characterized by a triad of anemia, diabetes mellitus and sensorineural deafness is caused by a deficiency of a thiamine transporter protein. The disorder is rare and has not been reported from our community which has high background of consanguinity. We report a six years old girl who presented with diabetes mellitus which remitted after thiamine replacement. The girl in addition had sensorineural deafness, reinopathy, atrial septal defect and megaloblastic anemia which responded to high doses of thymine. This is the first case reported from Kashmir valley and third from India. The presentation and management in such cases is discussed.
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Affiliation(s)
- Mohd Ashraf Ganie
- Department of Endocrinology, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
| | - Imran Ali
- Department of Endocrinology, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
| | - A. G. Ahangar
- Department of Cardiovascular Thoracic Surgery, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
| | - Mohd Maqbool Wani
- Department of Neurology, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
| | - Sanjeed Ahmed
- Department of Cardiovascular Thoracic Surgery, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
- Department of Radio Diagnosis, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
| | - Manzoor Ahmed Bhat
- Department of Endocrinology, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
| | - Sulaiman Seth
- Department of Endocrinology, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
| | - Syed Mudasir
- Department of Clinical Biochemistry, Sher-I-Kashmir Institute of Medical Sciences, Soura, Srinagar, Jammu and Kashmir, India
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17
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Luong KVQ, Nguyen LTH. The impact of thiamine treatment in the diabetes mellitus. J Clin Med Res 2012; 4:153-60. [PMID: 22719800 PMCID: PMC3376872 DOI: 10.4021/jocmr890w] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2012] [Indexed: 01/19/2023] Open
Abstract
Thiamine acts as a coenzyme for transketolase (Tk) and for the pyruvate dehydrogenase and α-ketoglutarate dehydrogenase complexes, enzymes which play a fundamental role for intracellular glucose metabolism. The relationship between thiamine and diabetes mellitus (DM) has been reported in the literature. Thiamine levels and thiamine-dependent enzyme activities have been reduced in DM. Genetic studies provide opportunity to link the relationship between thiamine and DM (such as Tk, SLC19A2 gene, transcription factor Sp1, α-1-antitrypsin, and p53). Thiamine and its derivatives have been demonstrated to prevent the activation of the biochemical pathways (increased flux through the polyol pathway, formation of advanced glycation end-products, activation of protein kinase C, and increased flux through the hexosamine biosynthesis pathway) induced by hyperglycemia in DM.Thiamine definitively has a role in the diabetic endothelial vascular diseases (micro and macroangiopathy), lipid profile, retinopathy, nephropathy, cardiopathy, and neuropathy.
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Subramanian VS, Subramanya SB, Said HM. Relative contribution of THTR-1 and THTR-2 in thiamin uptake by pancreatic acinar cells: studies utilizing Slc19a2 and Slc19a3 knockout mouse models. Am J Physiol Gastrointest Liver Physiol 2012; 302:G572-8. [PMID: 22194418 PMCID: PMC3311432 DOI: 10.1152/ajpgi.00484.2011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Thiamin is essential for normal function of pancreatic acinar cells, and its deficiency leads to a reduction in pancreatic digestive enzymes. We have recently shown that thiamin uptake by rat pancreatic acinar cells is carrier-mediated and that both thiamin transporter (THTR)-1 and THTR-2 are expressed in these cells; little, however, is known about the relative contribution of these transporters toward total carrier-mediated thiamin uptake by these cells. We addressed this issue using a gene-specific silencing approach (siRNA) in mouse-derived pancreatic acinar 266-6 cells and Slc19a2 and Slc19a3 knockout mouse models. First we established that thiamin uptake by mouse pancreatic acinar cells is via a carrier-mediated process. We also established that these cells as well as native human pancreas express THTR-1 and THTR-2, with expression of the former (and activity of its promoter) being significantly higher than that of the latter. Using gene-specific siRNA against mouse THTR-1 and THTR-2, we observed a significant inhibition in carrier-mediated thiamin uptake by 266-6 cells in both cases. Similarly, thiamin uptake by freshly isolated primary pancreatic acinar cells of the Slc19a2 and Slc19a3 knockout mice was significantly lower than uptake by acinar cells of the respective littermates; the degree of inhibition observed in the former knockout model was greater than that of the latter. These findings demonstrate, for the first time, that both mTHTR-1 and mTHTR-2 are involved in carrier-mediated thiamin uptake by pancreatic acinar cells.
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Akın L, Kurtoğlu S, Kendirci M, Akın MA, Karakükçü M. Does early treatment prevent deafness in thiamine-responsive megaloblastic anaemia syndrome? J Clin Res Pediatr Endocrinol 2011; 3:36-9. [PMID: 21448333 PMCID: PMC3065315 DOI: 10.4274/jcrpe.v3i1.08] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Accepted: 11/25/2010] [Indexed: 01/19/2023] Open
Abstract
Thiamine-responsive megaloblastic anaemia (TRMA; OMIM 249270) syndrome is an autosomal recessive disorder characterized by diabetes mellitus, megaloblastic anaemia, and sensorineural deafness. Progressive hearing loss is one of the cardinal findings of the syndrome and is known to be irreversible. Whether the deafness in TRMA syndrome can be prevented is not yet known. Here, we report a four-month-old female infant diagnosed with TRMA syndrome at an early age. There was no hearing loss at the time of diagnosis. The patient's initial auditory evoked brainstem response measurements were normal. Although she was given thiamine supplementation regularly following the diagnosis, the patient developed moderate sensorineural hearing loss at 20 months of age, indicating that early diagnosis and treatment with oral thiamine (100 mg/day) could not prevent deafness in TRMA syndrome. It would be premature to draw general conclusions from one case, but we believe that further patient-based observations can shed light on the pathophysiology of this rare syndrome as well as prediction of its prognosis.
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Affiliation(s)
- Leyla Akın
- Erciyes University, Faculty of Medicine Department of Pediatric Endocrinology, Kayseri, Turkey.
| | - Selim Kurtoğlu
- Department of Pediatrics, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Mustafa Kendirci
- Department of Pediatrics, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Mustafa Ali Akın
- Department of Pediatrics, Erciyes University Faculty of Medicine, Kayseri, Turkey
| | - Musa Karakükçü
- Department of Pediatrics, Erciyes University Faculty of Medicine, Kayseri, Turkey
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20
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21
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Ashokkumar B, Kumar JS, Hecht GA, Said HM. Enteropathogenic Escherichia coli inhibits intestinal vitamin B1 (thiamin) uptake: studies with human-derived intestinal epithelial Caco-2 cells. Am J Physiol Gastrointest Liver Physiol 2009; 297:G825-33. [PMID: 19628653 PMCID: PMC2763801 DOI: 10.1152/ajpgi.00250.2009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2009] [Accepted: 07/20/2009] [Indexed: 01/31/2023]
Abstract
Infection with the gram-negative enteropathogenic Escherichia coli (EPEC), a food-borne pathogen, represents a significant risk to human health. Whereas diarrhea is a major consequence of this infection, malnutrition also occurs especially in severe and prolonged cases, which may aggravate the health status of the infected hosts. Here we examined the effect of EPEC infection on the intestinal uptake of the water-soluble vitamin B1 (thiamin) using an established human intestinal epithelial Caco-2 cell model. The results showed that infecting Caco-2 cells with wild-type EPEC (but not with nonpathogenic E. coli, killed EPEC, or filtered supernatant) leads to a significant (P < 0.01) inhibition in thiamin uptake. Kinetic parameters of both the nanomolar (mediated by THTR-2) and the micromolar (mediated by THTR-1) saturable thiamin uptake processes were affected by EPEC infection. Cell surface expression of hTHTR-1 and -2 proteins, (determined by the biotinylation method) showed a significantly (P < 0.01) lower expression in EPEC-treated cells compared with controls. EPEC infection also affected the steady-state mRNA levels as well as promoter activity of the SLC19A2 and SLC19A3 genes. Infecting Caco-2 cells with EPEC mutants that harbor mutations in the escN gene (which encodes a putative ATPase for the EPEC type III secretion system, TTSS) or the espA, espB, or espD genes (which encode structural components of the TTSS) did not affect thiamin uptake. On the other hand, mutations in espF and espH genes (which encode effector proteins) exhibited partial inhibition in thiamin uptake. These results demonstrate for the first time that EPEC infection of human intestinal epithelial cells leads to inhibition in thiamin uptake via effects on physiological and molecular parameters of hTHTR-1 and -2. Furthermore, the inhibition appears to be dependent on a functional TTSS of EPEC.
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Affiliation(s)
- Balasubramaniem Ashokkumar
- Department of Medical Research, Veterans Administration Medical Center, Long Beach, California 90822, USA
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22
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Mee L, Nabokina SM, Sekar VT, Subramanian VS, Maedler K, Said HM. Pancreatic beta cells and islets take up thiamin by a regulated carrier-mediated process: studies using mice and human pancreatic preparations. Am J Physiol Gastrointest Liver Physiol 2009; 297:G197-206. [PMID: 19423748 PMCID: PMC2711754 DOI: 10.1152/ajpgi.00092.2009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Thiamin is essential for the normal function of the endocrine pancreas, but very little is known about uptake mechanism(s) and regulation by beta cells. We addressed these issues using mouse-derived pancreatic beta-TC-6 cells, and freshly isolated primary mouse and human pancreatic islets. Results showed that thiamin uptake by beta-TC-6 cells involves a pH (but not Na+)-dependent carrier-mediated process that is saturable at both the nanomolar (apparent K(m) = 37.17 +/- 9.9 nM) and micromolar (apparent K(m) = 3.26 +/- 0.86 microM) ranges, cis-inhibited by thiamin structural analogs, and trans-stimulated by unlabeled thiamin. Involvement of carrier-mediated process was also confirmed in primary mouse and human pancreatic islets. Both THTR-1 and THTR-2 were found to be expressed in these mouse and human pancreatic preparations. Maintaining beta-TC-6 cells in the presence of a high level of thiamin led to a significant (P < 0.01) decrease in thiamin uptake, which was associated with a significant downregulation in level of expression of THTR-1 and THTR-2 at the protein and mRNA levels and a decrease in transcriptional (promoter) activity. Modulators of intracellular Ca2+/calmodulin- and protein-tyrosine kinase-mediated pathways also altered thiamin uptake. Finally, confocal imaging of live beta-TC-6 cells showed that clinical mutants of THTR-1 have mixed expression phenotypes and all led to impairment in thiamin uptake. These studies demonstrate for the first time that thiamin uptake by the endocrine pancreas is carrier mediated and is adaptively regulated by the prevailing vitamin level via transcriptional mechanisms. Furthermore, clinical mutants of THTR-1 impair thiamin uptake via different mechanisms.
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Affiliation(s)
- Lisa Mee
- Veterans Affairs Medical Center-151, 5901 E. 7th St., Long Beach, CA 90822, USA.
| | - Svetlana M. Nabokina
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
| | - V. Thillai Sekar
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
| | - Veedamali S. Subramanian
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
| | - Kathrin Maedler
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
| | - Hamid M. Said
- Veterans Affairs Medical Center, Long Beach, California and Departments of Medicine and Physiology/Biophysics, University of California College of Medicine, Irvine, California; and Center of Biomolecular Interaction, University Bremen, Bremen, Germany
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Bouyahia O, Ouderni M, Mansour FB, Matoussi N, Khaldi F. Diabetic Acido-Ketosis Revealing Thiamine Responsive Megaloblastic Anemia. Qatar Med J 2008. [DOI: 10.5339/qmj.2008.2.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Thiamine-responsive megaloblastic anemia (TRMA) is a rare autosomal recessive disorder including megaloblastic anemia, thrombocytopaenia, diabetes mellitus and progressive sensorineural deafness. We report cases of two infants, aged respectively four and five months, hospitalized for diabetic-acido-ketosis requiring insulin therapy. Laboratory tests revealed megaloblasic anemia, thrombocytopenia and normal thiamine-levels. Neurosensorial investigations showed bilateral deafness and ophthalmic involvements. Treatment with oral thiamine normalized hematological parameters and ameliorated diabetes.
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Affiliation(s)
- O. Bouyahia
- Service de Medicine Infantile A, Hospital d’ Enfants de Tunis Tunis, Tunisia
| | - M. Ouderni
- Service de Medicine Infantile A, Hospital d’ Enfants de Tunis Tunis, Tunisia
| | - F. B. Mansour
- Service de Medicine Infantile A, Hospital d’ Enfants de Tunis Tunis, Tunisia
| | - N. Matoussi
- Service de Medicine Infantile A, Hospital d’ Enfants de Tunis Tunis, Tunisia
| | - F. Khaldi
- Service de Medicine Infantile A, Hospital d’ Enfants de Tunis Tunis, Tunisia
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Kurtoglu S, Hatipoglu N, Keskin M, Kendirci M, Akcakus M. Thiamine withdrawal can lead to diabetic ketoacidosis in thiamine responsive megaloblastic anemia: report of two siblings. J Pediatr Endocrinol Metab 2008; 21:393-7. [PMID: 18556972 DOI: 10.1515/jpem.2008.21.4.393] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thiamine responsive megaloblastic anemia syndrome (TRMA), an autosomal recessive disorder caused by the deficiency of thiamine transporter protein, is the association of diabetes mellitus, anemia and deafness. Pharmacological dose thiamine normalizes hematological abnormalities and their effects on the course of diabetes mellitus. We report on 8 years follow up of two siblings with TRMA. They presented in the prepubertal period with diabetic ketoacidosis due to lack of thiamine supplementation for 2 months. Their insulin requirements fell rapidly and disappeared with thiamine therapy. Hematological parameters normalized within 30 days. The diabetic picture is responsive to thiamine treatment in patients with TRMA. Insulin dependent diabetes may occur throughout the pubertal period. If thiamine supplementation is not sufficient, ketoacidosis may develop in patients during the prepubertal period.
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Affiliation(s)
- Selim Kurtoglu
- Division of Paediatric Endocrinology and Metabolism, Department of Paediatrics, Faculty of Medicine, Erciyes University, Kayseri, Turkey.
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Kalra S, Ahuja R, Mutti E, Veber D, Seetharam S, Scalabrino G, Seetharam B. Cobalamin-mediated regulation of transcobalamin receptor levels in rat organs. Arch Biochem Biophys 2007; 463:128-32. [PMID: 17442257 DOI: 10.1016/j.abb.2007.03.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 03/06/2007] [Accepted: 03/07/2007] [Indexed: 01/19/2023]
Abstract
Total gastrectomy (TG) causes cobalamin (Cbl) deficiency followed by increases in tumor necrosis factor (TNF)-alpha levels in the spinal cord (SC) of the rat. In order to understand how Cbl deficiency may influence cell Cbl transport, we have measured by immunoblotting protein levels of the receptor for the Cbl-transcobalamin (TC) complex (TC-R) in both animal and cell models. TC-R protein levels were elevated in the total membranes of duodenal mucosa, kidneys, liver, and SC of rats made Cbl-deficient (Cbl-D) by means of TG or feeding with a Cbl-D diet. Postoperative Cbl-replacement treatment normalized the TC-R protein levels in each of the tested organs, regardless of whether this treatment was given during the first two post-TG or during the third and fourth post-TG mo. In Caco-2 cells, progressively increasing TNF-alpha concentrations supplemented to culture medium induced an up-regulation of TC-R protein levels. We provide the first evidence of the regulation of a Cbl-specific receptor by the vitamin itself in some rat organs.
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Affiliation(s)
- Seema Kalra
- Department of Medicine, Medical College of Wisconsin, 5000 West National Avenue, Milwaukee, 53295 WI, USA
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27
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Subramanian VS, Mohammed ZM, Molina A, Marchant JS, Vaziri ND, Said HM. Vitamin B1 (thiamine) uptake by human retinal pigment epithelial (ARPE-19) cells: mechanism and regulation. J Physiol 2007; 582:73-85. [PMID: 17463047 PMCID: PMC2075275 DOI: 10.1113/jphysiol.2007.128843] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Accepted: 04/23/2007] [Indexed: 01/19/2023] Open
Abstract
Retinal abnormality and visual disturbances occur in thiamine-responsive megaloblastic anaemia (TRMA), an autosomal recessive disorder caused by mutations in the human thiamine transporter-1 (hTHTR-1). Human retinal pigment epithelial cells play a pivotal role in supplying thiamine to the highly metabolically active retina but nothing is known about the mechanism, regulation or biological processes involved in thiamine transport in these cells. To address these issues, we used human-derived retinal pigment epithelial ARPE-19 cells to characterize the thiamine uptake process. Thiamine uptake is energy- and temperature-dependent, pH-sensitive, Na+-independent, saturable at both the nanomolar (apparent Km, 30 +/- 5 nM) and the micromolar (apparent Km, 1.72 +/- 0.3 microM) concentration ranges, specific for thiamine and sensitive to sulfhydryl group inhibition. The diuretic amiloride caused a concentration-dependent inhibition in thiamine uptake, whereas the anti-trypanosomal drug, melarsoprol, failed to affect the uptake process. Both hTHTR-1 and hTHTR-2 are expressed in ARPE-19 cells as well as in native human retinal tissue with expression of the former being significantly higher than that of the latter. Uptake of thiamine was adaptively regulated by extracellular substrate level via transcriptionally mediated mechanisms that involve both hTHTR-1 and hTHTR-2; it was also regulated by an intracellular Ca2+-calmodulin-mediated pathway. Confocal imaging of living ARPE-19 cells expressing TRMA-associated hTHTR-1 mutants (D93H, S143F and G172D) showed various expression phenotypes. These results demonstrate for the first time the existence of a specialized and regulated uptake process for thiamine in a cellular model of human retinal pigment epithelia that involves hTHTR-1 and hTHTR-2. Further, clinically relevant mutations in hTHTR-1 lead to impaired cell surface expression or function of the transporter in retinal epithelial ARPE-19 cells.
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Ricketts CJ, Minton JA, Samuel J, Ariyawansa I, Wales JK, Lo IF, Barrett TG. Thiamine-responsive megaloblastic anaemia syndrome: long-term follow-up and mutation analysis of seven families. Acta Paediatr 2006; 95:99-104. [PMID: 16373304 DOI: 10.1080/08035250500323715] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
AIM Thiamine-responsive megaloblastic anaemia syndrome (TRMA) is the association of diabetes mellitus, anaemia and deafness, due to mutations in SLC19A2, encoding a thiamine transporter protein. This is a unique monogenic form of vitamin-dependent diabetes for which there is limited long-term data. We aimed to study genotype-phenotype relationships and long-term follow-up in our cohort. METHODS We have studied 13 patients from seven families and have follow-up data for a median of 9 y (2-30 y). RESULTS All patients originated from Kashmir or Punjab, and presented with non-immune, insulin-deficient diabetes mellitus, sensorineural deafness and a variable anaemia in the first 5 y of life, the anaemia progressing to megaloblastic and sideroblastic changes in the bone marrow. The anaemia and diabetes mellitus responded to oral thiamine hydrochloride 25 mg/d, but during puberty thiamine supplements became ineffective, and almost all patients require insulin therapy and regular blood transfusions in adulthood. All patients are homozygous for mutations in the SLC19A2 gene. We have identified a novel missense mutation (T158R) that was excluded in 100 control alleles. CONCLUSION Diabetes in this syndrome is due to an insulin insufficiency that initially responds to thiamine supplements; however, most patients become fully insulin dependent after puberty. A mutation screening strategy is feasible and likely to identify mutations in almost all cases.
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Affiliation(s)
- Christopher J Ricketts
- Medical and Molecular Genetics, Medical School, University of Birmingham, Birmingham, UK
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Baron D, Assaraf YG, Drori S, Aronheim A. Disruption of transport activity in a D93H mutant thiamine transporter 1, from a Rogers Syndrome family. ACTA ACUST UNITED AC 2004; 270:4469-77. [PMID: 14622275 DOI: 10.1046/j.1432-1033.2003.03839.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Rogers syndrome is an autosomal recessive disorder resulting in megaloblastic anemia, diabetes mellitus, and sensorineural deafness. The gene associated with this disease encodes for thiamine transporter 1 (THTR1), a member of the SLC19 solute carrier family including THTR2 and the reduced folate carrier (RFC). Using transient transfections into NIH3T3 cells of a D93H mutant THTR1derived from a Rogers syndrome family, we determined the expression, post-translational modification, plasma membrane targeting and thiamine transport activity. We also explored the impact on methotrexate (MTX) transport activity of a homologous missense D88H mutation in the human RFC, a close homologue of THTR1. Western blot analysis revealed that the D93H mutant THTR1 was normally expressed and underwent a complete N-glycosylation. However, while this mutant THTR1 was targeted to the plasma membrane, it was completely devoid of thiamine transport activity. Consistently, introduction into MTX transport null cells of a homologous D88H mutation in the hRFC did not result in restoration of MTX transport activity, thereby suggesting that D88 is an essential residue for MTX transport activity. These results suggest that the D93H mutation does not interfere with transporter expression, glycosylation and plasma membrane targeting. However, the substitution of this negatively charged amino acid (Asp93) by a positively charged residue (His) in an extremely conserved region (the border of transmembrane domain 2/intracellular loop 2) in the SLC19 family, presumably inflicts deleterious structural alterations that abolish thiamine binding and/or translocation. Hence, this functional characterization of the D93H mutation provides a molecular basis for Rogers syndrome.
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Affiliation(s)
- Dana Baron
- Department of Molecular Genetics, The Rappaport Institute for Research in the Medical Sciences and the B. Rappaport Faculty of Medicine, Haifa, Israel
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30
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Boros LG, Steinkamp MP, Fleming JC, Lee WNP, Cascante M, Neufeld EJ. Defective RNA ribose synthesis in fibroblasts from patients with thiamine-responsive megaloblastic anemia (TRMA). Blood 2003; 102:3556-61. [PMID: 12893755 DOI: 10.1182/blood-2003-05-1537] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Fibroblasts from patients with thiamine-responsive megaloblastic anemia (TRMA) syndrome with diabetes and deafness undergo apoptotic cell death in the absence of supplemental thiamine in their cultures. The basis of megaloblastosis in these patients has not been determined. Here we use the stable [1,2-13C2]glucose isotope-based dynamic metabolic profiling technique to demonstrate that defective high-affinity thiamine transport primarily affects the synthesis of nucleic acid ribose via the nonoxidative branch of the pentose cycle. RNA ribose isolated from TRMA fibroblasts in thiamine-depleted cultures shows a time-dependent decrease in the fraction of ribose derived via transketolase, a thiamine-dependent enzyme in the pentose cycle. The fractional rate of de novo ribose synthesis from glucose is decreased several fold 2 to 4 days after removal of thiamine from the culture medium. No such metabolic changes are observed in wild-type fibroblasts or in TRMA mutant cells in thiamine-containing medium. Fluxes through glycolysis are similar in TRMA versus control fibroblasts in the pentose and TCA cycles. We conclude that reduced nucleic acid production through impaired transketolase catalysis is the underlying biochemical disturbance that likely induces cell cycle arrest or apoptosis in bone marrow cells and leads to the TRMA syndrome in patients with defective high-affinity thiamine transport.
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Affiliation(s)
- László G Boros
- Stable Isotope Research Laboratory, Harbor-University of California, Los Angeles Research and Education Institute, UCLA School of Medicine, 1124 West Carson St, RB1, Torrance, CA 90502, USA.
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31
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Fleming JC, Tartaglini E, Kawatsuji R, Yao D, Fujiwara Y, Bednarski JJ, Fleming MD, Neufeld EJ. Male infertility and thiamine-dependent erythroid hypoplasia in mice lacking thiamine transporter Slc19a2. Mol Genet Metab 2003; 80:234-41. [PMID: 14567973 DOI: 10.1016/s1096-7192(03)00141-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thiamine-responsive megaloblastic anemia with diabetes and deafness (TRMA) is an autosomal recessive disease caused by mutations in the high-affinity thiamine transporter gene SLC19A2. To study the role of thiamine transport in the pathophysiology of TRMA syndrome and of each of the component disorders, we created a targeted disruption of the Slc19a2 gene in mice. Slc19a2 -/- mice are viable and females are fertile. Male -/- mice on a pure 129/Sv background are infertile with small testes (testis/body weight=0.13 +/- 0.04 knockout vs. 0.35 +/- 0.05 wild type, P<0.000005). The lack of developing germ cells beyond primary spermatocytes suggests an arrest in spermatogenesis prior to meiosis II. Nuclear chromatin changes indicative of apoptosis are present. No mature sperm are found in the tubules or epididymis. This phenotype suggests a previously unknown role for thiamine transport in spermatogenesis and male fertility. Slc19a2 -/- mice on a pure 129/Sv background develop reticulocytopenia after two weeks on thiamine-depleted chow with a virtual absence of reticulocytes in the peripheral blood (0.12% knockout vs. 2.58% wild type, P=0.0079). Few erythroid precursors are found in the bone marrow. Contrary to human TRMA syndrome, we see no evidence of megaloblastosis or ringed sideroblasts in the bone marrow of Slc19a2 -/- mice in thiamine-replete or thiamine-deficient dietary states. Phenotypic differences between TRMA patients and Slc19a2 -/- mice might be explained by dissimilar tissue expression patterns of the transporter, as well as by differing metabolic needs and possible different species-specific contributions of the related thiamine transporter Slc19a3.
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Affiliation(s)
- Judith C Fleming
- Division of Hematology, Children's Hospital, Dana-Farber Cancer Institute, and Harvard Medical School, Boston, MA 02115, USA
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32
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Lorber A, Gazit AZ, Khoury A, Schwartz Y, Mandel H. Cardiac manifestations in thiamine-responsive megaloblastic anemia syndrome. Pediatr Cardiol 2003; 24:476-81. [PMID: 14627317 DOI: 10.1007/s00246-002-0215-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thiamine-responsive megaloblastic anemia (TRMA) syndrome is a rare autosomal recessive disorder defined by the occurrence of megaloblastic anemia, diabetes mellitus, and sensorineural deafness, responding in varying degrees to thiamine treatment. Other features of this syndrome gradually develop. We describe three TRMA patients with heart rhythm abnormalities and structural cardiac anomalies. Eight other reported TRMA patients also had cardiac anomalies. Recently, the TRMA gene, SLC19A2, was identified, encoding a functional thiamine transporter. Characterization of the metabolic defect of TRMA may shed light on the role of thiamine in common cardiac abnormalities.
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Affiliation(s)
- A Lorber
- Department of Pediatric Cardiology, Rambam Medical Center, PO Box 9602, Haifa 31096, Israel
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33
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Ganapathy V, Smith SB, Prasad PD. SLC19: the folate/thiamine transporter family. Pflugers Arch 2003; 447:641-6. [PMID: 14770311 DOI: 10.1007/s00424-003-1068-1] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2003] [Accepted: 03/25/2003] [Indexed: 02/07/2023]
Abstract
The SLC19 gene family of solute carriers is a family of three transporter proteins with significant structural similarity, transporting, however, substrates with different structure and ionic charge. The three members of this gene family are expressed ubiquitously and mediate the transport of two important water-soluble vitamins, folate and thiamine. The concentrative transport of substrates mediated by the members of this gene family is energized by transcellular H(+)/OH(-) gradient. SLC19A1 is expressed at highest levels in absorptive cells where it is located in a polarized manner either in the apical or basal membrane, depending on the cell type. It mediates the transport of reduced folate and its analogs, such as methotrexate, which are anionic at physiological pH. SLC19A2 is expressed ubiquitously and mediates the transport of thiamine, a cation at physiological pH. SLC19A3 is also widely expressed and is capable of transporting thiamine. This review summarizes the current knowledge on the structural, functional, molecular and physiological aspects of the SLC19 gene family.
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Affiliation(s)
- Vadivel Ganapathy
- Department of Biochemistry and Molecular Biology, Medical College of Georgia, GA 30912-2100, Augusta, USA,
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34
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Kipioti A, George NDL, Hoffbrand AV, Sheridan E. Cone-rod dystrophy in thiamine-responsive megaloblastic anemia. J Pediatr Ophthalmol Strabismus 2003; 40:105-7. [PMID: 12691235 DOI: 10.3928/0191-3913-20030301-12] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Affiliation(s)
- A Kipioti
- Department of Ophthalmology, Leeds General Infirmary, Leeds, Yorkshire, United Kingdom
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35
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Ozdemir MA, Akcakus M, Kurtoglu S, Gunes T, Torun YA. TRMA syndrome (thiamine-responsive megaloblastic anemia): a case report and review of the literature. Pediatr Diabetes 2002; 3:205-9. [PMID: 15016149 DOI: 10.1034/j.1399-5448.2002.30407.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Thiamine-responsive megaloblastic anemia syndrome (TRMA) is an autosomal recessive disorder with features that include megaloblastic anemia, mild thrombocytopenia and leukopenia, sensorineural deafness and diabetes mellitus. In this disease, the active thiamine uptake into cells is disturbed. Treatment with pharmacological doses of thiamine ameliorates the megaloblastic anemia and diabetes mellitus. Previous studies have demonstrated that the disease is caused by mutations in the SLC19A2 gene encoding a high-affinity thiamine transporter. We present a 5-yr-old-boy with TRMA and, because of its rarity, we review the literature.
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Affiliation(s)
- Mehmet Akif Ozdemir
- Erciyes University School of Medicine Department of Pediatrics, Kayseri, Turkey.
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36
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Abstract
The sideroblastic anemias are a heterogeneous group of acquired and inherited bone marrow disorders defined by the presence of pathologic iron deposits in erythroblast mitochondria. While the pathogenesis of almost all cases of acquired sideroblastic anemia is unknown, the molecular genetic basis for several of the inherited forms have now been described. Initially, mutations in ALAS2 in X-linked sideroblastic anemia (XLSA) focused attention on the heme biosynthetic pathway as a primary cause of sideroblastic anemia. However, the subsequent description of the genes involved in XLSA with ataxia, thiamine-responsive megaloblastic anemia, and Pearson marrow-pancreas syndrome have implicated other pathways, including mitochondrial oxidative phosphorylation, thiamine metabolism, and iron-sulfur cluster biosynthesis, as primary defects in sideroblastic anemias that may only secondarily impact heme metabolism.
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Affiliation(s)
- Mark D Fleming
- Department of Pathology, Children's Hospital, Boston, MA 02115, USA
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37
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Baron D, Assaraf YG, Cohen N, Aronheim A. Lack of Plasma Membrane Targeting of a G172D Mutant Thiamine Transporter Derived from Rogers Syndrome Family. Mol Med 2002. [DOI: 10.1007/bf03402026] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
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38
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Balamurugan K, Said HM. Functional role of specific amino acid residues in human thiamine transporter SLC19A2: mutational analysis. Am J Physiol Gastrointest Liver Physiol 2002; 283:G37-43. [PMID: 12065289 DOI: 10.1152/ajpgi.00547.2001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
SLC19A2 is a membrane thiamine transporter expressed in a variety of human tissues, including the gastrointestinal tract. Little is currently known about the structure/function relationship of SLC19A2. We examined the effect of introducing mutations in SLC19A2 identical to those found in thiamine-responsive megaloblastic anemia syndrome (TRMA), on functional activity and membrane expression of the transporter. We also examined the effect of mutating the only conserved anionic residue (E138) in the transmembrane (TM) domains of the SLC19A2 and that of the putative glycosylation sites (N63, N314). Northern blot analysis showed SLC19A2 mRNA was expressed at the same level in HeLa cells transfected with wild-type or mutated SLC19A2. Introducing the clinically relevant mutations (D93H, S143F, G172D) or mutation at the conserved anionic residue (E138A) of SLC19A2 led to a significant (P < 0.01) inhibition of thiamine uptake. Mutations of the two potential N-linked glycosylation sites (N63Q, N314Q) of SLC19A2 did not affect functional activity; they did, however, lead to a noticeable reduction in apparent molecular weight of protein. Western blot analysis showed all proteins (except D93H) were expressed in the membrane (not the cytoplasmic) fraction of HeLa cells. These results provide direct confirmation that clinically relevant mutations in SLC19A2 observed in TRMA cause malfunctioning of the transporter and/or a defect in its translation/stability. Results also show conserved TM anionic residue of the SLC19A2 protein is critical for its function. Furthermore, native SLC19A2 is glycosylated, but this is not important for its function.
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39
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Lo PK, Wang FF. Identification of transcriptional start sites and splicing of mouse thiamine transporter gene THTR-1 (Slc19a2). BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1576:209-13. [PMID: 12031504 DOI: 10.1016/s0167-4781(02)00305-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
We have previously reported the cDNA cloning of the mouse thiamine transporter THTR-1 as a p53 transcriptional target gene (renamed THTR-1a hereinafter). The mouse THTR-1a is predicted to encode a protein of 12 hydrophobic stretches and a hydrophilic loop of 87 amino acids between transmembrane helices VI and VII. The mouse THTR-1 gene has been cloned, two major transcriptional start sites located at -175 and -183 relative to the translation start codon were identified. In addition, we have cloned a spliced variant, designated THTR-1b, from mouse liver cDNA library. This isoform is characterized by an inframe deletion of 114 nucleotides from the 3'-terminal region of exon 2, predicting the expression of a truncated protein lacking the central 38 amino acids of the loop region. THTR-1b coexpressed with THTR-1a in many of the mouse tissues and in day-7 to day-17 embryos, but in lower levels than the THTR-1a. When expressed in mammalian cells, both isoforms were able to mediate the transport of thiamine. Therefore, the transport function of the mouse THTR-1 is not determined by the central 38 amino acids of its loop region.
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Affiliation(s)
- Pang-Kuo Lo
- Institute of Biochemistry, National Yang-Ming University, 155 Li-Nong St, Sec. 2, Shih-Pai, Taipei, 112 Taiwan
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40
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Zhao R, Gao F, Goldman ID. Reduced folate carrier transports thiamine monophosphate: an alternative route for thiamine delivery into mammalian cells. Am J Physiol Cell Physiol 2002; 282:C1512-7. [PMID: 11997266 DOI: 10.1152/ajpcell.00547.2001] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Although the reduced folate carrier RFC1 and the thiamine transporters THTR-1 and THTR-2 share approximately 40% of their identity in protein sequence, RFC1 does not transport thiamine and THTR-1 and THTR-2 do not transport folates. In the present study, we demonstrate that transport of thiamine monophosphate (TMP), an important thiamine metabolite present in plasma and cerebrospinal fluid, is mediated by RFC1 in L1210 murine leukemia cells. Transport of TMP was augmented by a factor of five in cells (R16) that overexpress RFC1 and was markedly inhibited by methotrexate, an RFC1 substrate, but not by thiamine. At a near-physiological concentration (50 nM), TMP influx mediated by RFC1 in wild-type L1210 cells was approximately 50% of thiamine influx mediated by thiamine transporter(s). Within 1 min, the majority of TMP transported into R16 cells was hydrolyzed to thiamine with a component metabolized to thiamine pyrophosphate, the active enzyme cofactor. These data suggest that RFC1 may be one of the alternative transport routes available for TMP in some tissues when THTR-1 is mutated in the autosomal recessive disorder thiamine-responsive megaloblastic anemia.
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Affiliation(s)
- Rongbao Zhao
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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41
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Neufeld EJ, Fleming JC, Tartaglini E, Steinkamp MP. Thiamine-responsive megaloblastic anemia syndrome: a disorder of high-affinity thiamine transport. Blood Cells Mol Dis 2001; 27:135-8. [PMID: 11358373 DOI: 10.1006/bcmd.2000.0356] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thiamine-responsive megaloblastic anemia (TRMA) syndrome (OMIM No. 249270) comprises a distinctive triad of clinical features: megaloblastic anemia with ringed sideroblasts, diabetes mellitus, and progressive sensorineural deafness. The TRMA gene has been mapped and cloned. Designated "SLC19A2" as a member of the solute carrier gene superfamily, this gene is mutated in all TRMA kindreds studied to date. The product of the SLC19A2 gene is a membrane protein which transports thiamine (vitamin B1) with sub-micromolar affinity. Cells from TRMA patients are uniquely sensitive to thiamine depletion to the nanomolar range, while pharmacologic doses of vitamin B1 ameliorate the anemia and diabetes. Here we review the current status of studies aimed at understanding the pathophysiology of this unique transport defect.
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Affiliation(s)
- E J Neufeld
- Division of Hematology, Children's Hospital, Boston, Massachusetts 02115, USA.
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42
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Fleming JC, Steinkamp MP, Kawatsuji R, Tartaglini E, Pinkus JL, Pinkus GS, Fleming MD, Neufeld EJ. Characterization of a murine high-affinity thiamine transporter, Slc19a2. Mol Genet Metab 2001; 74:273-80. [PMID: 11592824 DOI: 10.1006/mgme.2001.3241] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thiamine-responsive megaloblastic anemia with deafness and diabetes (TRMA) is a rare autosomal recessive disorder of thiamine transport. Previous studies have demonstrated that the disease is caused by mutations in the SLC19A2 gene encoding a high-affinity thiamine transporter. We hypothesize that thiamine transport, mediated by SLC19A2, plays a role in the development and or maintenance of several organ systems, in particular the erythropoietic, auditory, and glucose homeostasis systems. To investigate the transporter further, we cloned the murine Slc19a2 locus and characterized the resulting protein. Murine Slc19a2 is a 498 amino acid protein, with 12 predicted transmembrane domains. The gene spans approximately 13kb with 6 exons, structurally identical to that of the human homolog. We localized the Slc19a2 gene to mouse chromosome 1, a region syntenic to human chromosome 1q23 that contains the TRMA locus. Transient expression of Slc19a2 in HEK293T cells resulted in specific uptake of [3H] thiamine, confirming a thiamine transporter function. Western blot analysis of mouse tissues reveals a wide distribution of Slc19a2 protein. Immunohistochemistry studies indicate that Slc19a2 is expressed on the cell surface and intracellularly, and is specifically localized to a subpopulation of cells in cochlea, small intestine, and pancreas.
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Affiliation(s)
- J C Fleming
- Division of Hematology, Children's Hospital, Boston, Massachusetts 02115, USA
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43
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Oishi K, Hirai T, Gelb BD, Diaz GA. Slc19a2: cloning and characterization of the murine thiamin transporter cDNA and genomic sequence, the orthologue of the human TRMA gene. Mol Genet Metab 2001; 73:149-59. [PMID: 11386850 DOI: 10.1006/mgme.2001.3184] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Recently, our group and others cloned the TRMA disease gene, SLC19A2, which encodes a thiamin transporter. Here, we report the cloning and characterization of the full-length cDNA and genomic sequences of mouse Slc19a2. The Slc19a2 cDNA contained a 1494-bp open-reading frame, and had 5'- and 3'-untranslated regions of 189 and 1857 bp, respectively. A putative GC-rich, TATA-less promoter was identified in genomic sequence directly upstream of the identified 5' end. The Slc19a2 gene spanned 16.3 kb and was organized into six exons, a gene structure conserved with the human orthologue. The predicted Slc19a2 protein, like SLC19A2, was predicted to have 12 transmembrane domains and shared a number of other conserved sequence motifs with the human orthologue, including one potential N-glycosylation site (N(63)) and several potential phosphorylation sites. Comparison of the Slc19a2 amino acid sequence with those of the other known SLC19A solute carriers highlighted interesting patterns of conservation and divergence in various domains, allowing insight into potential structure-function relationships. The identification of the mouse Slc19a2 cDNA and genomic sequences will facilitate the generation of an animal model of TRMA, permitting future studies of disease pathogenesis.
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MESH Headings
- Amino Acid Sequence
- Anemia, Megaloblastic/drug therapy
- Anemia, Megaloblastic/genetics
- Animals
- Base Sequence
- Blotting, Northern
- Carrier Proteins/genetics
- Cloning, Molecular
- DNA/chemistry
- DNA/genetics
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Exons
- Gene Expression
- Genes/genetics
- Introns
- Male
- Membrane Transport Proteins
- Mice
- Molecular Sequence Data
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Sequence Alignment
- Sequence Analysis, DNA
- Sequence Homology, Amino Acid
- Thiamine/therapeutic use
- Tissue Distribution
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Affiliation(s)
- K Oishi
- Department of Human Genetics, Mount Sinai School of Medicine, New York, New York 10029, USA
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44
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Gritli S, Omar S, Tartaglini E, Guannouni S, Fleming JC, Steinkamp MP, Berul CI, Hafsia R, Jilani SB, Belhani A, Hamdi M, Neufeld EJ. A novel mutation in the SLC19A2 gene in a Tunisian family with thiamine-responsive megaloblastic anaemia, diabetes and deafness syndrome. Br J Haematol 2001; 113:508-13. [PMID: 11380424 DOI: 10.1046/j.1365-2141.2001.02774.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Thiamine-responsive megaloblastic anaemia (TRMA) syndrome with diabetes and deafness was found in two patients from a Tunisian kindred. The proband was homozygous for a novel mutation, 287delG, in the high-affinity thiamine transporter gene, SLC19A2. We demonstrated that fibroblasts from this patient exhibited defective thiamine transport. These data confirm that the SLC19A2 gene is the high-affinity thiamine carrier and that this novel mutation is responsible for TRMA syndrome.
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Affiliation(s)
- S Gritli
- Division of Hematology and Oncology, Children's Hospital and Dana Farber Cancer Institute, Boston 02115, USA
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45
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Thameem F, Wolford JK, Bogardus C, Prochazka M. Analysis of slc19a2, on 1q23.3 encoding a thiamine transporter as a candidate gene for type 2 diabetes mellitus in pima indians. Mol Genet Metab 2001; 72:360-3. [PMID: 11286512 DOI: 10.1006/mgme.2001.3154] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Mutations in the SLC19A2 gene cause thiamine-responsive megaloblastic anemia (TRMA) frequently combined with diabetes mellitus and deafness. Type 2 diabetes mellitus is heritable and a region on 1q21-q23 encompassing SLC19A2 was linked with the disease in Pima Indians and Caucasians. We therefore investigated this candidate gene in selected diabetic and nondiabetic Pimas and found no variants. We conclude that mutations in SLC19A2 do not contribute to type 2 diabetes in this population.
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Affiliation(s)
- F Thameem
- Clinical Diabetes and Nutrition Section, Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, NIH, 4212 North 16th Street, Phoenix, Arizona 85016, USA.
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46
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Cascante M, Centelles JJ, Veech RL, Lee WN, Boros LG. Role of thiamin (vitamin B-1) and transketolase in tumor cell proliferation. Nutr Cancer 2001; 36:150-4. [PMID: 10890024 DOI: 10.1207/s15327914nc3602_2] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Metabolic control analysis predicts that stimulators of transketolase enzyme synthesis such as thiamin (vitamin B-1) support a high rate of nucleic acid ribose synthesis necessary for tumor cell survival, chemotherapy resistance, and proliferation. Metabolic control analysis also predicts that transketolase inhibitor drugs will have the opposite effect on tumor cells. This may have important implications in the nutrition and future treatment of patients with cancer.
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Affiliation(s)
- M Cascante
- Department of Biochemistry and Molecular Biology, Institut d'Investigacions Biomediques August Pi i Sunyer, University of Barcelona, Catalonia, Spain
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47
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Nosaka K, Onozuka M, Kakazu N, Hibi S, Nishimura H, Nishino H, Abe T. Isolation and characterization of a human thiamine pyrophosphokinase cDNA. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1517:293-7. [PMID: 11342111 DOI: 10.1016/s0167-4781(00)00247-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A human thiamine pyrophosphokinase cDNA clone (hTPK1) was isolated and sequenced. When the intact hTPK1 open reading frame was expressed as a histidine-tag fusion protein in Escherichia coli, marked enzyme activity was detected in the bacterial cells. The hTPK1 mRNA was widely expressed in various human tissues at a very low level, and the mRNA content in cultured fibroblasts was unaffected by the thiamine concentration of the medium. The chromosome localization of the hTPK1 gene was assigned to 7q34.
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MESH Headings
- Amino Acid Sequence
- Anemia, Megaloblastic/enzymology
- Anemia, Megaloblastic/genetics
- Blotting, Northern
- Chromosomes, Human, Pair 7
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- DNA, Complementary/isolation & purification
- Escherichia coli/genetics
- Escherichia coli/metabolism
- Fibroblasts/enzymology
- Humans
- In Situ Hybridization, Fluorescence
- Kidney/enzymology
- Leukocytes/enzymology
- Molecular Sequence Data
- Myocardium/enzymology
- RNA, Messenger/analysis
- RNA, Messenger/metabolism
- Sequence Alignment
- Thiamin Pyrophosphokinase/biosynthesis
- Thiamin Pyrophosphokinase/chemistry
- Thiamin Pyrophosphokinase/genetics
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Affiliation(s)
- K Nosaka
- Department of Chemistry, Kyoto Prefectural University of Medicine, Kita-ku, Kyoto 603-8334, Japan.
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Zhao R, Gao F, Wang Y, Diaz GA, Gelb BD, Goldman ID. Impact of the reduced folate carrier on the accumulation of active thiamin metabolites in murine leukemia cells. J Biol Chem 2001; 276:1114-8. [PMID: 11038362 DOI: 10.1074/jbc.m007919200] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The thiamin transporter encoded by SLC19A2 and the reduced folate carrier (RFC1) share 40% homology at the protein level, but the thiamin transporter does not mediate transport of folates. By using murine leukemia cell lines that express no, normal, or high levels of RFC1, we demonstrate that RFC1 does not mediate thiamin influx. However, high level RFC1 expression substantially reduced accumulation of the active thiamin coenzyme, thiamin pyrophosphate (TPP). This decreased level of TPP, synthesized intracellularly from imported thiamin, resulted from RFC1-mediated efflux of TPP. This conclusion was supported by the following observations. (i) Efflux of intracellular TPP was increased in cells with high expression of RFC1. (ii) Methotrexate inhibits TPP influx. (iii) TPP competitively inhibits methotrexate influx. (iv) Loading cells, which overexpress RFC1 to high levels of methotrexate to inhibit competitively RFC1-mediated TPP efflux, augment TPP accumulation. (v) There was an inverse correlation between thiamin accumulation and RFC1 activity in cells grown at a physiological concentration of thiamin. The modulation of thiamin accumulation by RFC1 in murine leukemia cells suggests that this carrier may play a role in thiamin homeostasis and could serve as a modifying factor in thiamin nutritional deficiency as well as when the high affinity thiamin transporter is mutated.
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Affiliation(s)
- R Zhao
- Department of Medicine and Molecular Pharmacology, and the Albert Einstein Comprehensive Cancer Center, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Scharfe C, Hauschild M, Klopstock T, Janssen AJ, Heidemann PH, Meitinger T, Jaksch M. A novel mutation in the thiamine responsive megaloblastic anaemia gene SLC19A2 in a patient with deficiency of respiratory chain complex I. J Med Genet 2000; 37:669-73. [PMID: 10978358 PMCID: PMC1734685 DOI: 10.1136/jmg.37.9.669] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The thiamine transporter gene SLC19A2 was recently found to be mutated in thiamine responsive megaloblastic anaemia with diabetes and deafness (TRMA, Rogers syndrome), an early onset autosomal recessive disorder. We now report a novel G1074A transition mutation in exon 4 of the SLC19A2 gene, predicting a Trp358 to ter change, in a girl with consanguineous parents. In addition to the typical triad of Rogers syndrome, the girl presented with short stature, hepatosplenomegaly, retinal degeneration, and a brain MRI lesion. Both muscle and skin biopsies were obtained before high dose thiamine supplementation. While no mitochondrial abnormalities were seen on morphological examination of muscle, biochemical analysis showed a severe deficiency of pyruvate dehydrogenase and complex I of the respiratory chain. In the patient's fibroblasts, the supplementation with high doses of thiamine resulted in restoration of complex I activity. In conclusion, we provide evidence that thiamine deficiency affects complex I activity. The clinical features of TRMA, resembling in part those found in typical mitochondrial disorders with complex I deficiency, may be caused by a secondary defect in mitochondrial energy production.
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Affiliation(s)
- C Scharfe
- Department of Medical Genetics, Klinikum Innenstadt, Ludwig-Maximilians- University, Munich, Germany
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Rindi G, Laforenza U. Thiamine intestinal transport and related issues: recent aspects. PROCEEDINGS OF THE SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE. SOCIETY FOR EXPERIMENTAL BIOLOGY AND MEDICINE (NEW YORK, N.Y.) 2000; 224:246-55. [PMID: 10964259 DOI: 10.1046/j.1525-1373.2000.22428.x] [Citation(s) in RCA: 116] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
In the intestinal lumen thiamine is in free form and very low concentrations. Absorption takes place primarily in the proximal part of the small intestine by means of a dual mechanism, which is saturable at low (physiological) concentrations and diffusive at higher. Thiamine undergoes intracellular phosphorylation mainly to thiamine pyrophosphate, while at the serosal side only free thiamine is present. Thiamine uptake is enhanced by thiamine deficiency, and reduced by thyroid hormone and diabetes. The entry of thiamine into the enterocyte, as evaluated in brush border membrane vesicles of rat small intestine in the absence of H+ gradient, is Na+- and biotransformation-independent, completely inhibited by thiamine analogs and reduced by ethanol administration and aging. The transport involves a saturable mechanism at low concentrations of vitamin and simple diffusion at higher. Outwardly oriented H+ gradients enhance thiamine transport, whose saturable component is a Na+-independent electroneutral uphill process utilizing energy supplied by the H+ gradient, and involving a thiamine/ H+ 1:1 stoichiometric exchange. The exit of thiamine from the enterocyte, as evaluated in basolateral membrane vesicles, is Na+-dependent, directly coupled to ATP hydrolysis by Na+-K+-ATPase, and inhibited by thiamine analogs. Transport of thiamine by renal brush border membrane vesicles is similar to the intestinal as far as both H+ gradient influence and specificity are concerned. In the erythrocyte thiamine transport is a Na+-independent, electroneutral process yet with two components: saturable, prevailing at low thiamine concentrations, and diffusive at higher. The saturable (specific) component is missing in patients of the rare disease known as thiamine-responsive megaloblastic anaemia (TRMA), producing a general disturbance of thiamine transport up to thiamine deficiency. The TRMA gene is located in chromosome 1q23.3. Recently, the thiamine transporter has been cloned: it is a protein of 497 amino acid residues with high homology with the reduced-folate transporter.
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Affiliation(s)
- G Rindi
- Institute of Human Physiology, University of Pavia, Pavia, Italy
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