1
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Stewart GW, Gibson JS, Rees DC. The cation-leaky hereditary stomatocytosis syndromes: A tale of six proteins. Br J Haematol 2023; 203:509-522. [PMID: 37679660 DOI: 10.1111/bjh.19093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 08/13/2023] [Accepted: 08/22/2023] [Indexed: 09/09/2023]
Abstract
This review concerns a series of dominantly inherited haemolytic anaemias in which the membrane of the erythrocyte 'leaks' the univalent cations, compromising the osmotic stability of the cell. The majority of the conditions are explained by mutations in one of six genes, coding for multispanning membrane proteins of different structure and function. These are: RhAG, coding for an ammonium carrier; SLC4A1, coding for the band 3 anion exchanger; PIEZO1, coding for a mechanosensitive cation channel; GLUT1, coding for a glucose transporter; KCNN4, coding for an internal-calcium-activated potassium channel; and ABCB6, coding for a porphyrin transporter. This review describes the five clinical syndromes associated with genetic defects in these genes and their variable genotype/phenotype relationships.
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Affiliation(s)
- Gordon W Stewart
- Division of Medicine, Faculty of Medical Sciences, University College London, London, UK
| | - John S Gibson
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - David C Rees
- Haematological Medicine, Kings College London, London, UK
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2
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Gibson JS, Stewart GW. A critical role for altered red cell cation permeability in pathogenesis of sickle cell disease and other haemolytic anaemias. Br J Haematol 2023; 202:462-464. [PMID: 37096935 DOI: 10.1111/bjh.18832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 04/13/2023] [Accepted: 04/14/2023] [Indexed: 04/26/2023]
Abstract
The aetiology of sickle cell disease is well known, but pathogenesis is complicated and details remain uncertain. A thorough understanding may suggest novel ways for designing more effective therapies. One area of importance, covered here in Nader et al., is the altered cation permeability of sickle cells and how the co-ordinated operation of a number of membrane transport proteins contributes to disease progression, all driven by the initial event of HbS polymerisation. There are echoes here of the cation leaks of hereditary stomatocytosis. Nader et al. propose a central role for PIEZO1, a novel mechanosensitive channel found in red cells, which may be aberrantly activated in sickle cells following HbS polymerisation and which may have potential as a novel target for future chemotherapies. Commentary on: Nader et al. Piezo1 activation augments sickling propensity and the adhesive properties of sickle red blood cells in a calcium-dependent manner. Br J Haematol 2023;202:657-668.
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Affiliation(s)
- John S Gibson
- Department of Veterinary Medicine, University of Cambridge, Cambridge, UK
| | - Gordon W Stewart
- Division of Medicine, Faculty of Medical Sciences, University College London, London, UK
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3
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Meli A, Linger R, Stevens-Hernandez CJ, Gyongyver G, Marks DC, Aung HH, Tan JCG, Cardigan R, Bruce LJ, New HV. The compound effect of irradiation and familial pseudohyperkalemia on potassium leak from red blood cells. Transfusion 2022; 62:2587-2595. [PMID: 36285891 DOI: 10.1111/trf.17159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 09/28/2022] [Accepted: 09/29/2022] [Indexed: 12/13/2022]
Abstract
BACKGROUND Familial pseudohyperkalemia (FP) is a rare asymptomatic condition characterized by an increased rate of potassium leak from red blood cells (RBC) on refrigeration. Gamma irradiation compromises RBC membrane integrity and accelerates potassium leakage. Here, we compared the effect of irradiation, applied early or late in storage, on FP versus non-FP RBC. STUDY DESIGN Five FP and 10 non-FP individuals from the National Institute for Health Research Cambridge BioResource, UK, and three FP and six non-FP individuals identified by Australian Red Cross Lifeblood consented to the study. Blood was collected according to standard practice in each center, held overnight at 18-24°C, leucocyte-depleted, and processed into red cell concentrates (RCC) in Saline Adenine Glucose Mannitol. On Day 1, RCC were split equally into six Red Cell Splits (RCS). Two RCS remained non-irradiated, two were irradiated on Day 1 and two were irradiated on Day 14. RBCs were tested over cold storage for quality parameters. RESULTS As expected, non-irradiated FP RCS had significantly higher supernatant potassium levels than controls throughout 28 days of storage (p < .001). When irradiated early, FP RCS released potassium at similar rates to control. When irradiated late, FP RCS supernatants had higher initial post-irradiation potassium concentration than controls but were similar to controls by the end of storage (14 days post-irradiation). No other parameters studied showed a significant difference between FP and control. DISCUSSION FP does not increase the rate of potassium leak from irradiated RBCs. Irradiation may cause a membrane defect similar to that in FP RBCs.
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Affiliation(s)
- Athinoula Meli
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK
| | - Rachel Linger
- National Institute for Health Research BioResource-Rare Diseases, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Christian J Stevens-Hernandez
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK.,Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Gyorffy Gyongyver
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK.,Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK
| | - Denese C Marks
- Research and Development, Australian Red Cross Lifeblood, Alexandria, Australia
| | - Htet Htet Aung
- Research and Development, Australian Red Cross Lifeblood, Alexandria, Australia
| | - Joanne C G Tan
- Research and Development, Australian Red Cross Lifeblood, Alexandria, Australia
| | - Rebecca Cardigan
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK.,Department of Haematology, University of Cambridge, Cambridge, UK
| | - Lesley J Bruce
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK.,Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK
| | - Helen V New
- Clinical Directorate, NHS Blood and Transplant, London, UK
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4
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Yang Y, Li G, Wang Y, Sun Y, Xu C, Wei Z, Zhang S, Gao L, Liu S, Zhao J. Facile discovery of red blood cell deformation and compromised membrane/skeleton assembly in Prader-Willi syndrome. Front Med 2022; 16:946-956. [PMID: 36385596 DOI: 10.1007/s11684-022-0962-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/06/2022] [Indexed: 11/18/2022]
Abstract
Prader-Willi syndrome (PWS) is a rare congenital disease with genetic alterations in chromosome 15. Although genetic disorders and DNA methylation abnormalities involved in PWS have been investigated to a significant degree, other anomalies such as those in erythrocytes may occur and these have not been clearly elucidated. In the present study, we uncovered slight anemia in children with PWS that was associated with increased red blood cell (RBC) distribution width (RDW) and contrarily reduced hematocrit (HCT) values. Intriguingly, the increased ratio in RDW to HCT allowed sufficient differentiation between the PWS patients from the healthy controls and, importantly, with individuals exhibiting conventional obesity. Further morphologic examinations revealed a significant deformity in erythrocytes and mild hemolysis in PWS patients. Comprehensive mechanistic investigations unveiled compromised membrane skeletal assembly and membrane lipid composition, and revealed a reduced F-actin/G-actin ratio in PWS patients. We ascribed these phenotypic changes in erythrocytes to the observed genetic defects, including DNA methylation abnormalities. Our collective data allowed us to uncover RBC deformation in children with PWS, and this may constitute an auxiliary indicator of PWS in early childhood.
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Affiliation(s)
- Yashuang Yang
- Department of Endocrinology, Shandong Provincial Hospital, Shandong University, Jinan, 250021, China.,Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China.,Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, 250021, China
| | - Guimei Li
- Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Yanzhou Wang
- Department of Pediatric Orthopedics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Yan Sun
- Department of Pediatrics, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Chao Xu
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China.,Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, 250021, China
| | - Zhen Wei
- Medical Social Work Office, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China
| | - Shuping Zhang
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 250117, China.
| | - Ling Gao
- Department of Endocrinology, Shandong Provincial Hospital, Shandong University, Jinan, 250021, China.,Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China.,Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, 250021, China
| | - Sijin Liu
- Medical Science and Technology Innovation Center, Shandong First Medical University & Shandong Academy of Medical Sciences, Jinan, 250117, China
| | - Jiajun Zhao
- Department of Endocrinology, Shandong Provincial Hospital, Shandong University, Jinan, 250021, China. .,Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan, 250021, China. .,Shandong Key Laboratory of Endocrinology and Lipid Metabolism, Jinan, 250021, China.
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5
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Xiong W, Song J, Yue Z, Pei L, Liu Y, Chen J, Chen H. Case Report: Familial Pseudohyperkalemia Due to Red Blood Cell Membrane Leak in a Chinese Patient. Front Med (Lausanne) 2022; 9:825174. [PMID: 35372423 PMCID: PMC8969824 DOI: 10.3389/fmed.2022.825174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 02/22/2022] [Indexed: 12/02/2022] Open
Abstract
Hyperkalemia is a critical condition requiring careful evaluation and timely intervention. Many conditions could manifest as pseudohyperkalemia and it's important to differentiate them as inappropriate potassium-lowering therapy might lead to detrimental outcomes. A 56-year-old female was admitted for hyperkalemia (5.62–8.55 mmol/L). She had no symptoms or signs of hyperkalemia. A comprehensive work-up of hyperkalemia retrieved no valuable findings. Her blood samples underwent incubation tests at different temperatures and revealed temperature-dependent potassium leaks from red blood cells. Based on all test results, a diagnosis of hyperkalemia caused by red blood cell membrane defects was suspected. Whole-genome sequencing revealed a heterozygous c.1123C>T (p. R375W) mutation in the ABCB6 gene and confirmed the diagnosis of familial pseudohyperkalemia (FP). FP is an inherited benign condition in which red blood cells have increased cold-induced permeability to potassium. The patient was discharged with no additional treatment and she was suggested avoiding blood donation.
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Affiliation(s)
- Weijue Xiong
- Department of Cardiology, Peking University People's Hospital, Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Center for Cardiovascular Translational Research, Beijing, China
| | - Junxian Song
- Department of Cardiology, Peking University People's Hospital, Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Center for Cardiovascular Translational Research, Beijing, China
| | - Zhihong Yue
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Lin Pei
- Department of Clinical Laboratory, Peking University People's Hospital, Beijing, China
| | - Yang Liu
- Department of Hematology, Peking University People's Hospital, Beijing, China
| | - Jiangtian Chen
- Department of Cardiology, Peking University People's Hospital, Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Center for Cardiovascular Translational Research, Beijing, China
| | - Hong Chen
- Department of Cardiology, Peking University People's Hospital, Beijing Key Laboratory of Early Prediction and Intervention of Acute Myocardial Infarction, Center for Cardiovascular Translational Research, Beijing, China
- *Correspondence: Hong Chen
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6
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Meli A, McAndrew M, Frary A, Rehnstrom K, Stevens-Hernandez CJ, Flatt JF, Griffiths A, Stefanucci L, Astle W, Anand R, New HV, Bruce LJ, Cardigan R. Familial pseudohyperkalemia induces significantly higher levels of extracellular potassium in early storage of red cell concentrates without affecting other standard measures of quality: A case control and allele frequency study. Transfusion 2021; 61:2439-2449. [PMID: 33960432 DOI: 10.1111/trf.16440] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 03/15/2021] [Accepted: 04/03/2021] [Indexed: 12/20/2022]
Abstract
BACKGROUND Familial pseudohyperkalemia (FP) is characterized by an increased rate of potassium leakage in refrigerated red cells and is associated with the minor allele of the single nucleotide polymorphism rs148211042 (R723Q) in the ABCB6 gene. The study aims were to obtain the minor allele frequencies of ABCB6 variants and to measure supernatant potassium accumulation, and other red cell storage parameters, in red cell concentrates (RCC) from carriers of variant rs148211042 under standard blood bank conditions. STUDY DESIGN Whole blood units were collected from 6 FP individuals and 11 controls and processed into RCC in additive solution. RCC were sampled and tested over cold storage for full blood count, extracellular potassium, glucose, lactate, microvesicle release, deformability, hemolysis, pH, adenosine triphosphate, and 2,3-diphosphoglycerate. RESULTS Screening of genotyped cohorts identified that variant rs148211042 is present in 1 in 394 British citizens of European ancestry. FP RCC had significantly higher supernatant potassium at all time points from day 3 onwards (p < .001) and higher mean cell volume (p = .032) than controls. The initial rate of potassium release was higher in FP RCC; supernatant potassium reached 46.0 (23.8-57.6) mmol/L (mean [range]) by day 5, increasing to 68.9 (58.8-73.7) mmol/L by day 35. Other quality parameters were not significantly different between FP RCC and controls. CONCLUSION These data suggest that if a blood donor has FP, reducing the RCC shelf-life to 5 days may be insufficient to reduce the risk of hyperkalemia in clinical scenarios such as neonatal large volume transfusion.
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Affiliation(s)
- Athinoula Meli
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK
| | - Margaret McAndrew
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK
| | - Amy Frary
- Department of Haematology, University of Cambridge, Cambridge, UK.,National Institute for Health Research BioResource-Rare Diseases, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Karola Rehnstrom
- Department of Haematology, University of Cambridge, Cambridge, UK.,National Institute for Health Research BioResource-Rare Diseases, Cambridge University Hospitals NHS Foundation Trust, Cambridge, UK
| | - Christian J Stevens-Hernandez
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK.,Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK.,School of Biochemistry, University of Bristol, Bristol, UK
| | - Joanna F Flatt
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK
| | | | - Luca Stefanucci
- Department of Haematology, University of Cambridge, Cambridge, UK.,British Heart Foundation Centre of Excellence, Cambridge, UK
| | - William Astle
- Medical Research Council Biostatistics Unit, Cambridge Institute of Public Health, Cambridge, UK.,MRC/BHF Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Rekha Anand
- Clinical Directorate, NHS Blood and Transplant, Birmingham, UK
| | - Helen V New
- Clinical Directorate, NHS Blood and Transplant, London, UK.,Centre for Haematology, Imperial College London, London, UK
| | - Lesley J Bruce
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK.,Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, UK
| | - Rebecca Cardigan
- Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK.,Department of Haematology, University of Cambridge, Cambridge, UK
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7
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Petkova-Kirova P, Hertz L, Danielczok J, Huisjes R, Makhro A, Bogdanova A, Mañú-Pereira MDM, Vives Corrons JL, van Wijk R, Kaestner L. Red Blood Cell Membrane Conductance in Hereditary Haemolytic Anaemias. Front Physiol 2019; 10:386. [PMID: 31040790 PMCID: PMC6477063 DOI: 10.3389/fphys.2019.00386] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 03/21/2019] [Indexed: 11/18/2022] Open
Abstract
Congenital haemolytic anaemias are inherited disorders caused by red blood cell membrane and cytoskeletal protein defects, deviant hemoglobin synthesis and metabolic enzyme deficiencies. In many cases, although the causing mutation might be known, the pathophysiology and the connection between the particular mutation and the symptoms of the disease are not completely understood. Thus effective treatment is lagging behind. As in many cases abnormal red blood cell cation content and cation leaks go along with the disease, by direct electrophysiological measurements of the general conductance of red blood cells, we aimed to assess if changes in the membrane conductance could be a possible cause. We recorded whole-cell currents from 29 patients with different types of congenital haemolytic anaemias: 14 with hereditary spherocytosis due to mutations in α-spectrin, β-spectrin, ankyrin and band 3 protein; 6 patients with hereditary xerocytosis due to mutations in Piezo1; 6 patients with enzymatic disorders (3 patients with glucose-6-phosphate dehydrogenase deficiency, 1 patient with pyruvate kinase deficiency, 1 patient with glutamate-cysteine ligase deficiency and 1 patient with glutathione reductase deficiency), 1 patient with β-thalassemia and 2 patients, carriers of several mutations and a complex genotype. While the patients with β-thalassemia and metabolic enzyme deficiencies showed no changes in their membrane conductance, the patients with hereditary spherocytosis and hereditary xerocytosis showed largely variable results depending on the underlying mutation.
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Affiliation(s)
| | - Laura Hertz
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany.,Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Jens Danielczok
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany
| | - Rick Huisjes
- Department of Clinical Chemistry & Haematology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Asya Makhro
- Red Blood Cell Research Group, Institute of Veterinary Physiology, Vetsuisse Faculty, Zurich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zurich, Switzerland
| | - Anna Bogdanova
- Red Blood Cell Research Group, Institute of Veterinary Physiology, Vetsuisse Faculty, Zurich Center for Integrative Human Physiology (ZIHP), University of Zürich, Zurich, Switzerland
| | | | - Joan-Lluis Vives Corrons
- Red Blood Cell Defects and Hematopoietic Disorders Unit, Josep Carreras Leukaemia Research Institute, Barcelona, Spain
| | - Richard van Wijk
- Department of Clinical Chemistry & Haematology, University Medical Center Utrecht, Utrecht, Netherlands
| | - Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany.,Experimental Physics, Saarland University, Saarbrücken, Germany
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8
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Flatt JF, Bruce LJ. The Molecular Basis for Altered Cation Permeability in Hereditary Stomatocytic Human Red Blood Cells. Front Physiol 2018; 9:367. [PMID: 29713289 PMCID: PMC5911802 DOI: 10.3389/fphys.2018.00367] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 03/27/2018] [Indexed: 11/20/2022] Open
Abstract
Normal human RBCs have a very low basal permeability (leak) to cations, which is continuously corrected by the Na,K-ATPase. The leak is temperature-dependent, and this temperature dependence has been evaluated in the presence of inhibitors to exclude the activity of the Na,K-ATPase and NaK2Cl transporter. The severity of the RBC cation leak is altered in various conditions, most notably the hereditary stomatocytosis group of conditions. Pedigrees within this group have been classified into distinct phenotypes according to various factors, including the severity and temperature-dependence of the cation leak. As recent breakthroughs have provided more information regarding the molecular basis of hereditary stomatocytosis, it has become clear that these phenotypes elegantly segregate with distinct genetic backgrounds. The cryohydrocytosis phenotype, including South-east Asian Ovalocytosis, results from mutations in SLC4A1, and the very rare condition, stomatin-deficient cryohydrocytosis, is caused by mutations in SLC2A1. Mutations in RHAG cause the very leaky condition over-hydrated stomatocytosis, and mutations in ABCB6 result in familial pseudohyperkalemia. All of the above are large multi-spanning membrane proteins and the mutations may either modify the structure of these proteins, resulting in formation of a cation pore, or otherwise disrupt the membrane to allow unregulated cation movement across the membrane. More recently mutations have been found in two RBC cation channels, PIEZO1 and KCNN4, which result in dehydrated stomatocytosis. These mutations alter the activation and deactivation kinetics of these channels, leading to increased opening and allowing greater cation fluxes than in wild type.
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Affiliation(s)
- Joanna F Flatt
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, United Kingdom
| | - Lesley J Bruce
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant, Bristol, United Kingdom
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9
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Badens C, Guizouarn H. Advances in understanding the pathogenesis of the red cell volume disorders. Br J Haematol 2016; 174:674-85. [PMID: 27353637 DOI: 10.1111/bjh.14197] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Genetic defects of erythrocyte transport proteins cause disorders of red blood cell volume that are characterized by abnormal permeability to the cations Na(+) and K(+) and, consequently, by changes in red cell hydration. Clinically, these disorders are associated with chronic haemolytic anaemia of variable severity and significant co-morbidities, such as iron overload. This review provides an overview of recent insights into the molecular basis of this group of rare anaemias involving cation channels and transporters dysfunction. To date, a total of 5 different membrane proteins have been reported to be responsible for volume homeostasis alteration when mutated, 3 of them leading to overhydrated cells (AE1 [also termed SLC4A1], RHAG and GLUT1 [also termed SCL2A1) and 2 others to dehydrated cells (PIEZO1 and the Gardos Channel). These findings are not only of basic scientific interest, but also of direct clinical significance for improving diagnostic procedures and identify potential approaches for novel therapeutic strategies.
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Affiliation(s)
- Catherine Badens
- APHM Department of Medical Genetics, Hôpital de la Timone, Aix Marseille Univ, INSERM, GMGF, Marseille, France
| | - Hélène Guizouarn
- Univ. Nice Sophia Antipolis, CNRS, Inserm, iBV, 06100 Nice, France
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10
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King MJ, Garçon L, Hoyer JD, Iolascon A, Picard V, Stewart G, Bianchi P, Lee SH, Zanella A. ICSH guidelines for the laboratory diagnosis of nonimmune hereditary red cell membrane disorders. Int J Lab Hematol 2015; 37:304-25. [PMID: 25790109 DOI: 10.1111/ijlh.12335] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 01/22/2015] [Indexed: 01/19/2023]
Abstract
INTRODUCTION Hereditary spherocytosis (HS), hereditary elliptocytosis (HE), and hereditary stomatocytosis (HSt) are inherited red cell disorders caused by defects in various membrane proteins. The heterogeneous clinical presentation, biochemical and genetic abnormalities in HS and HE have been well documented. The need to raise the awareness of HSt, albeit its much lower prevalence than HS, is due to the undesirable outcome of splenectomy in these patients. METHODS The scope of this guideline is to identify the characteristic clinical features, the red cell parameters (including red cell morphology) for these red cell disorders associated, respectively, with defective cytoskeleton (HS and HE) and abnormal cation permeability in the lipid bilayer (HSt) of the red cell. The current screening tests for HS are described, and their limitations are highlighted. RESULTS An appropriate diagnosis can often be made when the screening test result(s) is reviewed together with the patient's clinical/family history, blood count results, reticulocyte count, red cell morphology, and chemistry results. SDS-polyacrylamide gel electrophoresis of erythrocyte membrane proteins, monovalent cation flux measurement, and molecular analysis of membrane protein genes are specialist tests for further investigation. CONCLUSION Specialist tests provide additional evidence in supporting the diagnosis and that will facilitate the management of the patient. In the case of a patient's clinical phenotype being more severe than the affected members within the immediate family, molecular testing of all family members is useful for confirming the diagnosis and allows an insight into the molecular basis of the abnormality such as a recessive mode of inheritance or a de novo mutation.
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Affiliation(s)
- M-J King
- Membrane Biochemistry, NHS Blood and Transplant, Bristol, UK
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11
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Bawazir WM, Flatt JF, Wallis JP, Rendon A, Cardigan RA, New HV, Wiltshire M, Page L, Chapman CE, Stewart GW, Bruce LJ. Familial pseudohyperkalemia in blood donors: a novel mutation with implications for transfusion practice. Transfusion 2014; 54:3043-50. [PMID: 24947683 DOI: 10.1111/trf.12757] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 04/07/2014] [Accepted: 05/13/2014] [Indexed: 11/28/2022]
Abstract
BACKGROUND Familial pseudohyperkalemia (FP) is a dominantly inherited condition in which red blood cells (RBCs) have an increased cold-induced permeability to monovalent cations. Potassium leaks into the supernatant of all stored blood with time, but FP RBCs leak potassium more rapidly. We investigated two unrelated blood donors whose RBC donations demonstrated unexpectedly high potassium after 5 and 6 days' storage. We matched the observed pattern of RBC cation leak to a previously recognized family with FP (FP-Cardiff) and investigated the likely cause with targeted DNA analysis. STUDY DESIGN AND METHODS Cation leakage from the donor RBCs and from standard donor units was measured. DNA analysis of donors and family members with FP-Cardiff was performed. Allele frequencies were obtained from human variation databases. RESULTS Both implicated donors were found to have increased cold-induced potassium leak identical in pattern to affected members of the family with FP-Cardiff. We found a heterozygous substitution Arg723Gln in the ATP-binding cassette, Subfamily B, Member 6 protein that segregated with FP in the Cardiff family and was also present in both blood donors. Arg723Gln is listed in human variation databases with an allele frequency of approximately 1:1000. CONCLUSIONS We describe a novel FP mutation that may affect 1:500 European blood donors and causes rapid loss of potassium from stored RBCs. This finding has implications for neonates and infants receiving large-volume RBC transfusions. Genomic screening of donors could be used to identify donors with this mutation and potentially improve the quality and safety of donor units.
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Affiliation(s)
- Waleed M Bawazir
- Bristol Institute for Transfusion Sciences, NHS Blood & Transplant, Bristol, UK; School of Biochemistry, University of Bristol, Bristol, UK
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12
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Flatt JF, Bawazir WM, Bruce LJ. The involvement of cation leaks in the storage lesion of red blood cells. Front Physiol 2014; 5:214. [PMID: 24987374 PMCID: PMC4060409 DOI: 10.3389/fphys.2014.00214] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 05/19/2014] [Indexed: 12/12/2022] Open
Abstract
Stored blood components are a critical life-saving tool provided to patients by health services worldwide. Red cells may be stored for up to 42 days, allowing for efficient blood bank inventory management, but with prolonged storage comes an unwanted side-effect known as the "storage lesion", which has been implicated in poorer patient outcomes. This lesion is comprised of a number of processes that are inter-dependent. Metabolic changes include a reduction in glycolysis and ATP production after the first week of storage. This leads to an accumulation of lactate and drop in pH. Longer term damage may be done by the consequent reduction in anti-oxidant enzymes, which contributes to protein and lipid oxidation via reactive oxygen species. The oxidative damage to the cytoskeleton and membrane is involved in increased vesiculation and loss of cation gradients across the membrane. The irreversible damage caused by extensive membrane loss via vesiculation alongside dehydration is likely to result in immediate splenic sequestration of these dense, spherocytic cells. Although often overlooked in the literature, the loss of the cation gradient in stored cells will be considered in more depth in this review as well as the possible effects it may have on other elements of the storage lesion. It has now become clear that blood donors can exhibit quite large variations in the properties of their red cells, including microvesicle production and the rate of cation leak. The implications for the quality of stored red cells from such donors is discussed.
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Affiliation(s)
- Joanna F Flatt
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant Bristol, UK
| | - Waleed M Bawazir
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant Bristol, UK ; School of Biochemistry, University of Bristol Bristol, UK
| | - Lesley J Bruce
- Bristol Institute for Transfusion Sciences, NHS Blood and Transplant Bristol, UK
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13
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Yabas M, Coupland LA, Cromer D, Winterberg M, Teoh NC, D'Rozario J, Kirk K, Bröer S, Parish CR, Enders A. Mice deficient in the putative phospholipid flippase ATP11C exhibit altered erythrocyte shape, anemia, and reduced erythrocyte life span. J Biol Chem 2014; 289:19531-7. [PMID: 24898253 DOI: 10.1074/jbc.c114.570267] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Transmembrane lipid transporters are believed to establish and maintain phospholipid asymmetry in biological membranes; however, little is known about the in vivo function of the specific transporters involved. Here, we report that developing erythrocytes from mice lacking the putative phosphatidylserine flippase ATP11C showed a lower rate of PS translocation in vitro compared with erythrocytes from wild-type littermates. Furthermore, the mutant mice had an elevated percentage of phosphatidylserine-exposing mature erythrocytes in the periphery. Although erythrocyte development in ATP11C-deficient mice was normal, the mature erythrocytes had an abnormal shape (stomatocytosis), and the life span of mature erythrocytes was shortened relative to that in control littermates, resulting in anemia in the mutant mice. Thus, our findings uncover an essential role for ATP11C in erythrocyte morphology and survival and provide a new candidate for the rare inherited blood disorder stomatocytosis with uncompensated anemia.
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Affiliation(s)
- Mehmet Yabas
- From the Ramaciotti Immunization Genomics Laboratory and
| | - Lucy A Coupland
- Cancer and Vascular Biology Group, Department of Immunology, The John Curtin School of Medical Research, and the Clinical Haematology Unit, The Canberra Hospital, Canberra, Australian Capital Territory 2605, Australia
| | - Deborah Cromer
- the Complex Systems in Biology Group, Centre for Vascular Research, University of New South Wales, Kensington, New South Wales 2052, Australia, and
| | - Markus Winterberg
- the Division of Biomedical Science and Biochemistry, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Narci C Teoh
- the Liver Research Group, Australian National University Medical School at the Canberra Hospital, Canberra, Australian Capital Territory 2605, Australia
| | - James D'Rozario
- the Clinical Haematology Unit, The Canberra Hospital, Canberra, Australian Capital Territory 2605, Australia
| | - Kiaran Kirk
- the Division of Biomedical Science and Biochemistry, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Stefan Bröer
- the Division of Biomedical Science and Biochemistry, Research School of Biology, Australian National University, Canberra, Australian Capital Territory 2601, Australia
| | - Christopher R Parish
- Cancer and Vascular Biology Group, Department of Immunology, The John Curtin School of Medical Research, and
| | - Anselm Enders
- From the Ramaciotti Immunization Genomics Laboratory and
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Multiple clinical forms of dehydrated hereditary stomatocytosis arise from mutations in PIEZO1. Blood 2013; 121:3925-35, S1-12. [PMID: 23479567 DOI: 10.1182/blood-2013-02-482489] [Citation(s) in RCA: 227] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Autosomal dominant dehydrated hereditary stomatocytosis (DHSt) usually presents as a compensated hemolytic anemia with macrocytosis and abnormally shaped red blood cells (RBCs). DHSt is part of a pleiotropic syndrome that may also exhibit pseudohyperkalemia and perinatal edema. We identified PIEZO1 as the disease gene for pleiotropic DHSt in a large kindred by exome sequencing analysis within the previously mapped 16q23-q24 interval. In 26 affected individuals among 7 multigenerational DHSt families with the pleiotropic syndrome, 11 heterozygous PIEZO1 missense mutations cosegregated with disease. PIEZO1 is expressed in the plasma membranes of RBCs and its messenger RNA, and protein levels increase during in vitro erythroid differentiation of CD34(+) cells. PIEZO1 is also expressed in liver and bone marrow during human and mouse development. We suggest for the first time a correlation between a PIEZO1 mutation and perinatal edema. DHSt patient red cells with the R2456H mutation exhibit increased ion-channel activity. Functional studies of PIEZO1 mutant R2488Q expressed in Xenopus oocytes demonstrated changes in ion-channel activity consistent with the altered cation content of DHSt patient red cells. Our findings provide direct evidence that R2456H and R2488Q mutations in PIEZO1 alter mechanosensitive channel regulation, leading to increased cation transport in erythroid cells.
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15
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King MJ, Zanella A. Hereditary red cell membrane disorders and laboratory diagnostic testing. Int J Lab Hematol 2013; 35:237-43. [PMID: 23480868 DOI: 10.1111/ijlh.12070] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 01/16/2013] [Indexed: 01/20/2023]
Abstract
This overview describes two groups of nonimmune hereditary hemolytic anemias caused by defects in membrane proteins located in distinct layers of the red cell membrane. Hereditary spherocytosis (HS), hereditary elliptocytosis (HE), and hereditary pyropoikilocytosis (HPP) represent disorders of the red cell cytoskeleton. Hereditary stomatocytoses represents disorders of cation permeability in the red cell membrane. The current laboratory screening tests for HS are the osmotic fragility test, acid glycerol lysis time test (AGLT), cryohemolysis test, and eosin-5'-maleimide (EMA)-binding test. For atypical HS, SDS-polyacrylamide gel electrophoresis of erythrocyte membrane proteins is carried out to confirm the diagnosis. The diagnosis of HE/HPP is based on abnormal red cell morphology and the detection of protein 4.1R deficiency or spectrin variants using gel electrophoresis. None of screening tests can detect all HS cases. Some testing centers (a survey of 25 laboratories) use a combination of tests (e.g., AGLT and EMA). No specific screening test for hereditary stomatocytoses is available. The preliminary diagnosis is based on presenting a compensated hemolytic anemia, macrocytosis, and a temperature or time dependent pseudohyperkalemia in some patients. Both the EMA-binding test and the osmotic fragility test may help in differential diagnosis of HS and hereditary stomatocytosis.
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Affiliation(s)
- M-J King
- Membrane Biochemistry, NHS Blood and Transplant, Bristol, UK.
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16
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Albuisson J, Murthy SE, Bandell M, Coste B, Louis-Dit-Picard H, Mathur J, Fénéant-Thibault M, Tertian G, de Jaureguiberry JP, Syfuss PY, Cahalan S, Garçon L, Toutain F, Simon Rohrlich P, Delaunay J, Picard V, Jeunemaitre X, Patapoutian A. Dehydrated hereditary stomatocytosis linked to gain-of-function mutations in mechanically activated PIEZO1 ion channels. Nat Commun 2013; 4:1884. [PMID: 23695678 PMCID: PMC3674779 DOI: 10.1038/ncomms2899] [Citation(s) in RCA: 249] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2013] [Accepted: 04/18/2013] [Indexed: 02/06/2023] Open
Abstract
Dehydrated hereditary stomatocytosis is a genetic condition with defective red blood cell membrane properties that causes an imbalance in intracellular cation concentrations. Recently, two missense mutations in the mechanically activated PIEZO1 (FAM38A) ion channel were associated with dehydrated hereditary stomatocytosis. However, it is not known how these mutations affect PIEZO1 function. Here, by combining linkage analysis and whole-exome sequencing in a large pedigree and Sanger sequencing in two additional kindreds and 11 unrelated dehydrated hereditary stomatocytosis cases, we identify three novel missense mutations and one recurrent duplication in PIEZO1, demonstrating that it is the major gene for dehydrated hereditary stomatocytosis. All the dehydrated hereditary stomatocytosis-associated mutations locate at C-terminal half of PIEZO1. Remarkably, we find that all PIEZO1 mutations give rise to mechanically activated currents that inactivate more slowly than wild-type currents. This gain-of-function PIEZO1 phenotype provides insight that helps to explain the increased permeability of cations in red blood cells of dehydrated hereditary stomatocytosis patients. Our findings also suggest a new role for mechanotransduction in red blood cell biology and pathophysiology.
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17
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Andolfo I, Alper SL, Delaunay J, Auriemma C, Russo R, Asci R, Esposito MR, Sharma AK, Shmukler BE, Brugnara C, De Franceschi L, Iolascon A. Missense mutations in the ABCB6 transporter cause dominant familial pseudohyperkalemia. Am J Hematol 2013. [PMID: 23180570 DOI: 10.1002/ajh.23357] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Familial Pseudohyperkalemia (FP) is a dominant red cell trait characterized by increased serum [K(+)] in whole blood stored at or below room temperature, without additional hematological abnormalities. Functional gene mapping and sequencing analysis of the candidate genes within the 2q35-q36 critical interval identified-in 20 affected individuals among three multigenerational FP families-two novel heterozygous missense mutations in the ABCB6 gene that cosegregated with disease phenotype. The two genomic substitutions altered two adjacent nucleotides within codon 375 of ABCB6, a porphyrin transporter that, in erythrocyte membranes, bears the Langereis blood group antigen system. The ABCB6 R375Q mutation did not alter the levels of mRNA or protein, or protein localization in mature erythrocytes or erythroid precursor cells, but it is predicted to modestly alter protein structure. ABCB6 mRNA and protein levels increase during in vitro erythroid differentiation of CD34(+) erythroid precursors and the erythroleukemia cell lines HEL and K562. These data suggest that the two missense mutations in residue 375 of the ABCB6 polypeptide found in affected individuals of families with chromosome 2-linked FP could contribute to the red cell K(+) leak characteristic of this condition.
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18
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Bawazir WM, Gevers EF, Flatt JF, Ang AL, Jacobs B, Oren C, Grunewald S, Dattani M, Bruce LJ, Stewart GW. An infant with pseudohyperkalemia, hemolysis, and seizures: cation-leaky GLUT1-deficiency syndrome due to a SLC2A1 mutation. J Clin Endocrinol Metab 2012; 97:E987-93. [PMID: 22492876 DOI: 10.1210/jc.2012-1399] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
CONTEXT GLUT1 (glucose transporter 1) deficiency syndrome is a well-known presentation in pediatric practice. Very rare mutations not only disable carbohydrate transport but also cause the red cell membrane to be constitutively permeant to monovalent cations, namely sodium and potassium. OBJECTIVE The aim of this study was to describe the pediatric presentation of a patient with GLUT1 deficiency with such a cation-leaky state. SUBJECT AND METHODS The infant presented with erratic hyperkalemia, neonatal hyperbilirubinemia, anemia, hepatic dysfunction, and microcephaly. Later, seizures occurred and developmental milestones were delayed. Magnetic resonance imaging and computerized tomography scans of the brain showed multiple abnormalities including periventricular calcification. Visual impairment was present due to the presence of both cataracts and retinal dysfunction. RESULTS Measurements of red cell cation content showed extremely leaky red cells (causing the hemolysis) and temperature-dependent loss of potassium from red cells (explaining the hyperkalemia as pseudohyperkalemia). A trinucleotide deletion in SLC2A1, coding for the deletion of isoleucine 435 or 436 in GLUT1, was identified in the proband. CONCLUSION This is the fourth pedigree to be described with this most unusual syndrome. The multisystem pathology probably reflects a combination of glucose transport deficiency at the blood-brain barrier (as in typical GLUT1 deficiency) and the deleterious osmotic effects of a cation-leaky membrane protein in the cells where GLUT1 is expressed, notably the red cell. We hope that this detailed description will facilitate rapid diagnosis of this disease entity.
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Affiliation(s)
- Waleed M Bawazir
- Division of Medicine, University College London, Rayne Building, University Street, London WC1E 6JF, United Kingsom
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19
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Shmukler BE, Rivera A, Vandorpe DH, Alves J, Bonfanti U, Paltrinieri S, Alper SL. Cation-leak stomatocytosis in standard schnauzers does not cosegregate with coding mutations in the RhAG, SLC4A1, or GLUT1 genes associated with human disease. Blood Cells Mol Dis 2012; 48:219-25. [PMID: 22406315 DOI: 10.1016/j.bcmd.2012.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Autosomal dominant overhydrated cation-leak stomatocytosis in humans has been associated with missense mutations in the erythroid membrane transport genes AE1, RhAG, and GLUT1. Syndromic stomatocytosis has been reported in three dog breeds, but stomatocytosis in Standard Schnauzers is usually asymptomatic, and is accompanied by minimal if any anemia. We have extended the evaluation of a cohort of schnauzers. We found that low-level stomatocytosis was accompanied by increased MCV and increased red cell Na content, and minimal or no reticulocytosis. Red cells from two affected dogs exhibited increased currents in on-cell patches measured in symmetrical NaCl solutions, but Na,K-ATPase and NKCC-mediated cation flux was minimal. Three novel coding polymorphisms found in canine RhAG cDNA and three novel polymorphisms found in canine SLC4A1 cDNA did not cosegregate with MCV or Na content. The GLUT1 cDNA sequence was normal. We conclude that unlike human overhydrated cation-leak stomatocytosis, stomatocytosis in this cohort of Standard Schnauzers is not caused by mutations in the genes encoding RhAG, SLC4A1, or GLUT1.
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Affiliation(s)
- Boris E Shmukler
- Dept. of Medicine, Beth Israel Deaconess Med. Ctr, Boston, MA 02215, United States
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20
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Stewart AK, Shmukler BE, Vandorpe DH, Rivera A, Heneghan JF, Li X, Hsu A, Karpatkin M, O'Neill AF, Bauer DE, Heeney MM, John K, Kuypers FA, Gallagher PG, Lux SE, Brugnara C, Westhoff CM, Alper SL. Loss-of-function and gain-of-function phenotypes of stomatocytosis mutant RhAG F65S. Am J Physiol Cell Physiol 2011; 301:C1325-43. [PMID: 21849667 PMCID: PMC3233792 DOI: 10.1152/ajpcell.00054.2011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2011] [Accepted: 08/11/2011] [Indexed: 11/22/2022]
Abstract
Four patients with overhydrated cation leak stomatocytosis (OHSt) exhibited the heterozygous RhAG missense mutation F65S. OHSt erythrocytes were osmotically fragile, with elevated Na and decreased K contents and increased cation channel-like activity. Xenopus oocytes expressing wild-type RhAG and RhAG F65S exhibited increased ouabain and bumetanide-resistant uptake of Li(+) and (86)Rb(+), with secondarily increased (86)Rb(+) influx sensitive to ouabain and to bumetanide. Increased RhAG-associated (14)C-methylammonium (MA) influx was severely reduced in RhAG F65S-expressing oocytes. RhAG-associated influxes of Li(+), (86)Rb(+), and (14)C-MA were pharmacologically distinct, and Li(+) uptakes associated with RhAG and RhAG F65S were differentially inhibited by NH(4)(+) and Gd(3+). RhAG-expressing oocytes were acidified and depolarized by 5 mM bath NH(3)/NH(4)(+), but alkalinized and depolarized by subsequent bath exposure to 5 mM methylammonium chloride (MA/MA(+)). RhAG F65S-expressing oocytes exhibited near-wild-type responses to NH(4)Cl, but MA/MA(+) elicited attenuated alkalinization and strong hyperpolarization. Expression of RhAG or RhAG F65S increased steady-state cation currents unaltered by bath Li(+) substitution or bath addition of 5 mM NH(4)Cl or MA/MA(+). These oocyte studies suggest that 1) RhAG expression increases oocyte transport of NH(3)/NH(4)(+) and MA/MA(+); 2) RhAG F65S exhibits gain-of-function phenotypes of increased cation conductance/permeability, and loss-of-function phenotypes of decreased and modified MA/MA(+) transport, and decreased NH(3)/NH(4)(+)-associated depolarization; and 3) RhAG transports NH(3)/NH(4)(+) and MA/MA(+) by distinct mechanisms, and/or the substrates elicit distinct cellular responses. Thus, RhAG F65S is a loss-of-function mutation for amine transport. The altered oocyte intracellular pH, membrane potential, and currents associated with RhAG or RhAG F65S expression may reflect distinct transport mechanisms.
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Affiliation(s)
- Andrew K Stewart
- Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, USA
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21
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Houston B, Zelinski T, Israels S, Coghlan G, Chodirker B, Gallagher P, Houston D, Zarychanski R. Refinement of the hereditary xerocytosis locus on chromosome 16q in a large Canadian kindred. Blood Cells Mol Dis 2011; 47:226-31. [DOI: 10.1016/j.bcmd.2011.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Stomatin-deficient cryohydrocytosis results from mutations in SLC2A1: a novel form of GLUT1 deficiency syndrome. Blood 2011; 118:5267-77. [DOI: 10.1182/blood-2010-12-326645] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
The hereditary stomatocytoses are a series of dominantly inherited hemolytic anemias in which the permeability of the erythrocyte membrane to monovalent cations is pathologically increased. The causative mutations for some forms of hereditary stomatocytosis have been found in the transporter protein genes, RHAG and SLC4A1. Glucose transporter 1 (glut1) deficiency syndromes (glut1DSs) result from mutations in SLC2A1, encoding glut1. Glut1 is the main glucose transporter in the mammalian blood-brain barrier, and glut1DSs are manifested by an array of neurologic symptoms. We have previously reported 2 cases of stomatin-deficient cryohydrocytosis (sdCHC), a rare form of stomatocytosis associated with a cold-induced cation leak, hemolytic anemia, and hepatosplenomegaly but also with cataracts, seizures, mental retardation, and movement disorder. We now show that sdCHC is associated with mutations in SLC2A1 that cause both loss of glucose transport and a cation leak, as shown by expression studies in Xenopus oocytes. On the basis of a 3-dimensional model of glut1, we propose potential mechanisms underlying the phenotypes of the 2 mutations found. We investigated the loss of stomatin during erythropoiesis and find this occurs during reticulocyte maturation and involves endocytosis. The molecular basis of the glut1DS, paroxysmal exercise-induced dyskinesia, and sdCHC phenotypes are compared and discussed.
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23
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Lukens MV, de Mare A, Kerbert-Dreteler MJ, van den Bergh FA. Leaky cell syndrome: a rare cause of pseudohyperkalaemia. Ann Clin Biochem 2011; 49:97-100. [DOI: 10.1258/acb.2011.011096] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Life-threatening situations of hyperkalaemia are often caused by renal failure, hyperglycaemia or medication. However pseudohyperkalaemia, a falsely elevated potassium concentration, is usually caused by haemolysis, repeated clenching of the fist during venepuncture or abnormal cell numbers. Another rare cause of pseudohyperkalaemia is familial pseudohyperkalaemia, an autosomal dominantly inherited trait, with increased leakage of potassium from erythrocytes. Under normal in vivo conditions, this increased leakage is compensated by augmented activity of the Na+/K+ ATPase pump. However, after venepuncture the blood cools down to room temperature, reducing the activity of the Na+/K+ ATPase pump whereby the increased potassium leakage becomes more apparent. Here, we present a Dutch patient with extreme familial pseudohyperkalaemia. Interestingly, his two children also show increased potassium leakage at room temperature, albeit at a lower level. Despite the low prevalence of familial pseudohyperkalaemia, it can have important clinical implications and rapid recognition is desired.
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Affiliation(s)
| | | | - Marjo J Kerbert-Dreteler
- Department of Gastroenterology, Medisch Spectrum Twente Hospital Group, PO Box 50000, Enschede 7500 KA, The Netherlands
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Band 3 missense mutations and stomatocytosis: insight into the molecular mechanism responsible for monovalent cation leak. Int J Cell Biol 2011; 2011:136802. [PMID: 21876696 PMCID: PMC3163022 DOI: 10.1155/2011/136802] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 05/27/2011] [Accepted: 05/29/2011] [Indexed: 02/03/2023] Open
Abstract
Missense mutations in the erythroid band 3 protein (Anion Exchanger 1) have been associated with hereditary stomatocytosis. Features of cation leaky red cells combined with functional expression of the mutated protein led to the conclusion that the AE1 point mutations were responsible for Na(+) and K(+) leak through a conductive mechanism. A molecular mechanism explaining mutated AE1-linked stomatocytosis involves changes in AE1 transport properties that become leaky to Na(+) and K(+). However, another explanation suggests that point-mutated AE1 could regulate a cation leak through other transporters. This short paper intends to discuss these two alternatives.
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25
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Relle M, Cash H, Brochhausen C, Strand D, Menke J, Galle PR, Schwarting A. New perspectives on the renal slit diaphragm protein podocin. Mod Pathol 2011; 24:1101-10. [PMID: 21499232 PMCID: PMC3182839 DOI: 10.1038/modpathol.2011.58] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Podocin is a critical component of the glomerular filtration barrier, its mutations causing recessive steroid-resistant nephrotic syndrome. A GenBank analysis of the human podocin (NPHS2) gene resulted in the possible existence of a new splice variant of podocin in the kidney, missing the in-frame of exon 5, encoding the prohibitin homology domain. Using RT-polymerase chain reaction and immunoblotting followed by sequence analysis, we are for the first time able to prove the expression of a novel podocin isoform (isoform 2), exclusively and constitutively expressed in human podocytes. Furthermore, we reveal singular extrarenal podocin expression in human and murine testis. Our data show the Sertoli cells of the seminiferous tubules to be the origin of testicular podocin. Confocal laser microscopy illustrates the co-localization of podocin with filamentous actin within Sertoli cells, suggesting a role of podocin in the blood/testis barrier. These results led to the rationale to examine podocin expression in testes of men with Sertoli cell-only syndrome, a disorder characterized by azoospermia. Interestingly, we observed a complete down-regulation of podocin mRNA in Sertoli cell-only syndrome, indicating a possible role of podocin in the pathogenesis of this germinal aplasia. Men with Sertoli cell-only syndrome show normal renal podocin expression, suggesting an alternate regulation of the testicular promoter. Our findings may change the perception of podocin and give new insights into the ultrastructure of glomerular slit diaphragm and the blood/testis barrier.
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Affiliation(s)
- Manfred Relle
- Department of Medicine, Johannes Gutenberg University, Mainz, Germany.
| | - Hannes Cash
- Department of Urology, Charité-University Medicine, Berlin, Germany
| | | | - Dennis Strand
- Department of Medicine, Johannes Gutenberg University, Mainz, Germany
| | - Julia Menke
- Department of Medicine, Johannes Gutenberg University, Mainz, Germany
| | - Peter R Galle
- Department of Medicine, Johannes Gutenberg University, Mainz, Germany
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26
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Stewart AK, Kedar PS, Shmukler BE, Vandorpe DH, Hsu A, Glader B, Rivera A, Brugnara C, Alper SL. Functional characterization and modified rescue of novel AE1 mutation R730C associated with overhydrated cation leak stomatocytosis. Am J Physiol Cell Physiol 2011; 300:C1034-46. [PMID: 21209359 PMCID: PMC3093938 DOI: 10.1152/ajpcell.00447.2010] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Accepted: 12/23/2010] [Indexed: 01/20/2023]
Abstract
We report the novel, heterozygous AE1 mutation R730C associated with dominant, overhydrated, cation leak stomatocytosis and well-compensated anemia. Parallel elevations of red blood cell cation leak and ouabain-sensitive Na(+) efflux (pump activity) were apparently unaccompanied by increased erythroid cation channel-like activity, and defined ouabain-insensitive Na(+) efflux pathways of nystatin-treated cells were reduced. Epitope-tagged AE1 R730C at the Xenopus laevis oocyte surface exhibited severely reduced Cl(-) transport insensitive to rescue by glycophorin A (GPA) coexpression or by methanethiosulfonate (MTS) treatment. AE1 mutant R730K preserved Cl(-) transport activity, but R730 substitution with I, E, or H inactivated Cl(-) transport. AE1 R730C expression substantially increased endogenous oocyte Na(+)-K(+)-ATPase-mediated (86)Rb(+) influx, but ouabain-insensitive flux was minimally increased and GPA-insensitive. The reduced AE1 R730C-mediated sulfate influx did not exhibit the wild-type pattern of stimulation by acidic extracellular pH (pH(o)) and, unexpectedly, was partially rescued by exposure to sodium 2-sulfonatoethyl methanethiosulfonate (MTSES) but not to 2-aminoethyl methanethiosulfonate hydrobromide (MTSEA) or 2-(trimethylammonium)ethyl methanethiosulfonate bromide (MTSET). AE1 R730E correspondingly exhibited acid pH(o)-stimulated sulfate uptake at rates exceeding those of wild-type AE1 and AE1 R730K, whereas mutants R730I and R730H were inactive and pH(o) insensitive. MTSES-treated oocytes expressing AE1 R730C and untreated oocytes expressing AE1 R730E also exhibited unprecedented stimulation of Cl(-) influx by acid pH(o). Thus recombinant cation-leak stomatocytosis mutant AE1 R730C exhibits severely reduced anion transport unaccompanied by increased Rb(+) and Li(+) influxes. Selective rescue of acid pH(o)-stimulated sulfate uptake and conferral of acid pH(o)-stimulated Cl(-) influx, by AE1 R730E and MTSES-treated R730C, define residue R730 as critical to selectivity and regulation of anion transport by AE1.
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Affiliation(s)
- Andrew K Stewart
- Division of Nephrology, Beth Israel Deaconess Medical Center, 330 Brookline Ave., Boston, MA 02215, USA
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Barneaud-Rocca D, Borgese F, Guizouarn H. Dual transport properties of anion exchanger 1: the same transmembrane segment is involved in anion exchange and in a cation leak. J Biol Chem 2011; 286:8909-16. [PMID: 21257764 PMCID: PMC3059035 DOI: 10.1074/jbc.m110.166819] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2010] [Revised: 01/19/2011] [Indexed: 11/06/2022] Open
Abstract
Previous results suggested that specific point mutations in human anion exchanger 1 (AE1) convert the electroneutral anion exchanger into a monovalent cation conductance. In the present study, the transport site for anion exchange and for the cation leak has been studied by cysteine scanning mutagenesis and sulfhydryl reagent chemistry. Moreover, the role of some highly conserved amino acids within members of the SLC4 family to which AE1 belongs has been assessed in AE1 transport properties. The results suggest that the same transport site within the AE1 spanning domain is involved in anion exchange or in cation transport. A functioning mechanism for this transport site is proposed according to transport properties of the different studied point mutations of AE1.
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Affiliation(s)
- Damien Barneaud-Rocca
- From the Institut de Biologie du Développement et Cancer, UMR6543 Université de Nice-Centre National de la Recherche Scientifique, 28 avenue Valrose, 06108 Nice cedex 2, France
| | - Franck Borgese
- From the Institut de Biologie du Développement et Cancer, UMR6543 Université de Nice-Centre National de la Recherche Scientifique, 28 avenue Valrose, 06108 Nice cedex 2, France
| | - Hélène Guizouarn
- From the Institut de Biologie du Développement et Cancer, UMR6543 Université de Nice-Centre National de la Recherche Scientifique, 28 avenue Valrose, 06108 Nice cedex 2, France
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Guizouarn H, Borgese F, Gabillat N, Harrison P, Goede JS, McMahon C, Stewart GW, Bruce LJ. South-east Asian ovalocytosis and the cryohydrocytosis form of hereditary stomatocytosis show virtually indistinguishable cation permeability defects. Br J Haematol 2011; 152:655-64. [DOI: 10.1111/j.1365-2141.2010.08454.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Föller M, Braun M, Qadri SM, Lang E, Mahmud H, Lang F. Temperature sensitivity of suicidal erythrocyte death. Eur J Clin Invest 2010; 40:534-40. [PMID: 20456488 DOI: 10.1111/j.1365-2362.2010.02296.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Fever and hyperthermia are frequently associated with anaemia. Under most clinical conditions, they are considered to be two mutually independent clinical consequences of a common cause. The present study explored the possibility that anaemia results from temperature-sensitive suicidal erythrocyte death or eryptosis. Eryptosis is characterised by cell shrinkage and cell membrane scrambling with phosphatidylserine (PS) exposure at the erythrocyte surface. It is triggered by increase in the cytosolic Ca(2+) activity on the one hand and by ceramide formation on the other. MATERIAL AND METHODS Annexin V-binding was utilised to disclose PS exposure, forward scatter to analyse cell volume, Fluo 3 fluorescence to estimate cytosolic Ca(2+) activity, binding of fluorescent antibodies to determine ceramide abundance and a luciferin/luciferase-based assay to measure the cytosolic ATP concentration. RESULTS Graded increases in temperature from 37 to 41 degrees C decreased the forward scatter and stimulated annexin V-binding of human erythrocytes. The effect was accompanied by increased cytosolic Ca(2+) activity, decrease of the cellular ATP content and a moderate rise in ceramide formation. The effect of hyperthermia on annexin V-binding was significantly blunted by the leukotriene receptor CysLT1 antagonist cinalukast (1 microM). CONCLUSIONS Hyperthermia stimulates Ca(2+) entry into erythrocytes leading to cell shrinkage and PS exposure. As PS-exposing erythrocytes are rapidly cleared from circulating blood, the eryptosis during hyperthermia may cause anaemia.
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Affiliation(s)
- Michael Föller
- Department of Physiology, University of Tübingen, Tübingen, Germany
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KOMATSU T, SATO K, OTSUKA Y, ARASHIKI N, TANAKA K, TAMAHARA S, ONO KI, INABA M. Parallel Reductions in Stomatin and Na,K-ATPase through the Exosomal Pathway during Reticulocyte Maturation in Dogs: Stomatin as a Genotypic and Phenotypic Marker of High K+ and Low K+ Red Cells. J Vet Med Sci 2010; 72:893-901. [DOI: 10.1292/jvms.10-0030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Affiliation(s)
- Tomohiko KOMATSU
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
| | - Kota SATO
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
| | - Yayoi OTSUKA
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
| | - Nobuto ARASHIKI
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
| | - Kohei TANAKA
- Laboratory of Clinical Pathobiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Satoshi TAMAHARA
- Laboratory of Clinical Pathobiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Ken-ichiro ONO
- Laboratory of Clinical Pathobiology, Graduate School of Agricultural and Life Sciences, The University of Tokyo
| | - Mutsumi INABA
- Laboratory of Molecular Medicine, Graduate School of Veterinary Medicine, Hokkaido University
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Iolascon A, De Falco L, Borgese F, Esposito MR, Avvisati RA, Izzo P, Piscopo C, Guizouarn H, Biondani A, Pantaleo A, De Franceschi L. A novel erythroid anion exchange variant (Gly796Arg) of hereditary stomatocytosis associated with dyserythropoiesis. Haematologica 2009; 94:1049-59. [PMID: 19644137 DOI: 10.3324/haematol.2008.002873] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND Stomatocytoses are a group of inherited autosomal dominant hemolytic anemias and include overhydrated hereditary stomatocytosis, dehydrated hereditary stomatocytosis, hereditary cryohydrocytosis and familial pseudohyperkalemia. DESIGN AND METHODS We report a novel variant of hereditary stomatocytosis due to a de novo band 3 mutation (p. G796R-band3 CEINGE) associated with a dyserythropoietic phenotype. Band 3 genomic analysis, measurement at of hematologic parameters and red cell indices and morphological analysis of bone marrow were carried out. We then evaluated the red cell membrane permeability and ion transport systems by functional studies of the patient's erythrocytes and Xenopus oocytes transfected with mutated band 3. We analyzed the red cell membrane tyrosine phosphorylation profile and the membrane association of the tyrosine kinases Syk and Lyn from the Src-family-kinase group, since the activity of the membrane cation transport pathways is related to cyclic phosphorylation-dephosphorylation events. RESULTS The patient showed mild hemolytic anemia with circulating stomatocytes together with signs of dyserythropoiesis. Her red cells displayed increased Na(+) content with decreased K(+)content and abnormal membrane cation transport activities. Functional characterization of band 3 CEINGE in Xenopus oocytes showed that the mutated band 3 is converted from being an anion exchanger (Cl(-), HCO(3)(-)) to being a cation pathway for Na(+) and K(+). Increased tyrosine phosphorylation of some red cell membrane proteins was observed in diseased erythrocytes. Syk and Lyn membrane association was increased in the patient's red cells compared to in normal controls, indicating perturbation of phospho-signaling pathways involved in cell volume regulation events. CONCLUSIONS Band 3 CEINGE alters function from that of anion exchange to cation transport, affects the membrane tyrosine phosphorylation profile, in particular of band 3 and stomatin, and its presence during red cell development likely contributes to dyserythropiesis.
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Affiliation(s)
- Achille Iolascon
- Department of Biochemistry and Medical Biotechnologies, University Federico II, Naples, Italy.
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Stewart AK, Vandorpe DH, Heneghan JF, Chebib F, Stolpe K, Akhavein A, Edelman EJ, Maksimova Y, Gallagher PG, Alper SL. The GPA-dependent, spherostomatocytosis mutant AE1 E758K induces GPA-independent, endogenous cation transport in amphibian oocytes. Am J Physiol Cell Physiol 2009; 298:C283-97. [PMID: 19907019 DOI: 10.1152/ajpcell.00444.2009] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The previously undescribed heterozygous missense mutation E758K was discovered in the human AE1/SLC4A1/band 3 gene in two unrelated patients with well-compensated hereditary spherostomatocytic anemia (HSt). Oocyte surface expression of AE1 E758K, in contrast to that of wild-type AE1, required coexpressed glycophorin A (GPA). The mutant polypeptide exhibited, in parallel, strong GPA dependence of DIDS-sensitive (36)Cl(-) influx, trans-anion-dependent (36)Cl(-) efflux, and Cl(-)/HCO(3)(-) exchange activities at near wild-type levels. AE1 E758K expression was also associated with GPA-dependent increases of DIDS-sensitive pH-independent SO(4)(2-) uptake and oxalate uptake with altered pH dependence. In marked contrast, the bumetanide- and ouabain-insensitive (86)Rb(+) influx associated with AE1 E758K expression was largely GPA-independent in Xenopus oocytes and completely GPA-independent in Ambystoma oocytes. AE1 E758K-associated currents in Xenopus oocytes also exhibited little or no GPA dependence. (86)Rb(+) influx was higher but inward cation current was lower in oocytes expressing AE1 E758K than previously reported in oocytes expressing the AE1 HSt mutants S731P and H734R. The pharmacological inhibition profile of AE1 E758K-associated (36)Cl(-) influx differed from that of AE1 E758K-associated (86)Rb(+) influx, as well as from that of wild-type AE1-mediated Cl(-) transport. Thus AE1 E758K-expressing oocytes displayed GPA-dependent surface polypeptide expression and anion transport, accompanied by substantially GPA-independent, pharmacologically distinct Rb(+) flux and by small, GPA-independent currents. The data strongly suggest that most of the increased cation transport associated with the novel HSt mutant AE1 E758K reflects activation of endogenous oocyte cation permeability pathways, rather than cation translocation through the mutant polypeptide.
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Affiliation(s)
- Andrew K Stewart
- Division of Nephrology, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02215, USA
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Mairhofer M, Steiner M, Salzer U, Prohaska R. Stomatin-like protein-1 interacts with stomatin and is targeted to late endosomes. J Biol Chem 2009; 284:29218-29. [PMID: 19696025 DOI: 10.1074/jbc.m109.014993] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The human stomatin-like protein-1 (SLP-1) is a membrane protein with a characteristic bipartite structure containing a stomatin domain and a sterol carrier protein-2 (SCP-2) domain. This structure suggests a role for SLP-1 in sterol/lipid transfer and transport. Because SLP-1 has not been investigated, we first studied the molecular and cell biological characteristics of the expressed protein. We show here that SLP-1 localizes to the late endosomal compartment, like stomatin. Unlike stomatin, SLP-1 does not localize to the plasma membrane. Overexpression of SLP-1 leads to the redistribution of stomatin from the plasma membrane to late endosomes suggesting a complex formation between these proteins. We found that the targeting of SLP-1 to late endosomes is caused by a GYXXPhi (Phi being a bulky, hydrophobic amino acid) sorting signal at the N terminus. Mutation of this signal results in plasma membrane localization. SLP-1 and stomatin co-localize in the late endosomal compartment, they co-immunoprecipitate, thus showing a direct interaction, and they associate with detergent-resistant membranes. In accordance with the proposed lipid transfer function, we show that, under conditions of blocked cholesterol efflux from late endosomes, SLP-1 induces the formation of enlarged, cholesterol-filled, weakly LAMP-2-positive, acidic vesicles in the perinuclear region. This massive cholesterol accumulation clearly depends on the SCP-2 domain of SLP-1, suggesting a role for this domain in cholesterol transfer to late endosomes.
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Affiliation(s)
- Mario Mairhofer
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Vienna A-1030, Austria
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36
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Hereditary stomatocytosis and cation leaky red cells — Recent developments. Blood Cells Mol Dis 2009; 42:216-22. [DOI: 10.1016/j.bcmd.2009.01.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2009] [Accepted: 01/20/2009] [Indexed: 12/22/2022]
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The monovalent cation leak in overhydrated stomatocytic red blood cells results from amino acid substitutions in the Rh-associated glycoprotein. Blood 2009; 113:1350-7. [DOI: 10.1182/blood-2008-07-171140] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
AbstractOverhydrated hereditary stomatocytosis (OHSt) is a rare dominantly inherited hemolytic anemia characterized by a profuse membrane leak to monovalent cations. Here, we show that OHSt red cell membranes contain slightly reduced amounts of Rh-associated glycoprotein (RhAG), a putative gas channel protein. DNA analysis revealed that the OHSt patients have 1 of 2 heterozygous mutations (t182g, t194c) in RHAG that lead to substitutions of 2 highly conserved amino acids (Ile61Arg, Phe65Ser). Unexpectedly, expression of wild-type RhAG in Xenopus laevis oocytes induced a monovalent cation leak; expression of the mutant RhAG proteins induced a leak about 6 times greater than that in wild type. RhAG belongs to the ammonium transporter family of proteins that form pore-like structures. We have modeled RhAG on the homologous Nitrosomonas europaea Rh50 protein and shown that these mutations are likely to lead to an opening of the pore. Although the function of RhAG remains controversial, this first report of functional RhAG mutations supports a role for RhAG as a cation pore.
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Walsh S, Borgese F, Gabillat N, Unwin R, Guizouarn H. Cation transport activity of anion exchanger 1 mutations found in inherited distal renal tubular acidosis. Am J Physiol Renal Physiol 2008; 295:F343-50. [PMID: 18524859 DOI: 10.1152/ajprenal.00587.2007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Anion exchanger 1 (AE1) is encoded by SLC4A1 and mediates electroneutral anion exchange across cell membranes. It is the most abundant protein in the red cell membrane, but it is also found in the basolateral membrane of renal alpha-intercalated cells, where it is required for normal urinary acidification. Recently, four point mutations in red cell AE1 have been described that convert the anion exchanger to a cation conductance. SLC4A1 mutations can also cause type 1 hypokalemic distal renal tubular acidosis (dRTA). We investigated the properties of four dRTA-associated AE1 mutations (R589H, G609R, S613F, and G701D) by heterologous expression in Xenopus laevis oocytes. Although these AE1 mutants are functional anion exchangers, unlike the red cell disease mutants, we found that they also demonstrated a cation leak. We found a large cation leak in the G701D mutant. This mutant normally requires coexpression with glycophorin A for surface membrane expression in red blood cells and oocytes. However, we found that coexpressing wild-type kidney AE1 with G701D in oocytes still caused a cation leak, consistent with heterodimerized G701D reaching the cell membrane and retaining its cation conductance property. These findings have potential structural and functional implications for AE1, and they indicate that while anion exchange and cation conductance properties are distinct, they can coexist.
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Affiliation(s)
- Stephen Walsh
- Laboratoire de Physiologie des Membranes Cellulaires, UMR6548, Centre National de la Recherche Scientifique-Université de Nice, Bâtiment de Sciences Naturelles, Nice, France.
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Guizouarn H, Martial S, Gabillat N, Borgese F. Point mutations involved in red cell stomatocytosis convert the electroneutral anion exchanger 1 to a nonselective cation conductance. Blood 2007; 110:2158-65. [PMID: 17554061 DOI: 10.1182/blood-2006-12-063420] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The anion exchanger 1 (AE1) is encoded by the SLC4A1 gene and catalyzes the electroneutral anion exchange across cell plasma membrane. It is the most abundant transmembrane protein expressed in red cell where it is involved in CO(2) transport. Recently, 4 new point mutations of SLC4A1 gene have been described leading to missense mutations in the protein sequence (L687P, D705Y, S731P, or H734R). These point mutations were associated with hemolytic anemia, and it was shown that they confer a cation transport feature to the human AE1. Facing this unexpected property for an electroneutral anion exchanger, we have studied the transport features of mutated hAE1 by expression in xenopus oocytes. Our results show that the point mutations of hAE1 convert the electroneutral anion exchanger to a cation conductance: the exchangers are no longer able to exchange Cl(-) and HCO(3)(-), whereas they transport Na(+) and K(+) through a conductive mechanism. These data shed new light on transport mechanisms showing the tiny difference, in terms of primary sequence, between an electroneutral exchange and a conductive pathway.
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Affiliation(s)
- Hélène Guizouarn
- Laboratoire de Physiologie Cellulaire et Moléculaire, Unité Mixte de Recherche 6548, Centre National de la Recherche Scientifique, Université de Nice, Bâtiment de Sciences Naturelles, Nice, France.
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41
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Huber TB, Schermer B, Müller RU, Höhne M, Bartram M, Calixto A, Hagmann H, Reinhardt C, Koos F, Kunzelmann K, Shirokova E, Krautwurst D, Harteneck C, Simons M, Pavenstädt H, Kerjaschki D, Thiele C, Walz G, Chalfie M, Benzing T. Podocin and MEC-2 bind cholesterol to regulate the activity of associated ion channels. Proc Natl Acad Sci U S A 2006; 103:17079-86. [PMID: 17079490 PMCID: PMC1859892 DOI: 10.1073/pnas.0607465103] [Citation(s) in RCA: 222] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The prohibitin (PHB)-domain proteins are membrane proteins that regulate a variety of biological activities, including mechanosensation, osmotic homeostasis, and cell signaling, although the mechanism of this regulation is unknown. We have studied two members of this large protein family, MEC-2, which is needed for touch sensitivity in Caenorhabditis elegans, and Podocin, a protein involved in the function of the filtration barrier in the mammalian kidney, and find that both proteins bind cholesterol. This binding requires the PHB domain (including palmitoylation sites within it) and part of the N-terminally adjacent hydrophobic domain that attaches the proteins to the inner leaflet of the plasma membrane. By binding to MEC-2 and Podocin, cholesterol associates with ion-channel complexes to which these proteins bind: DEG/ENaC channels for MEC-2 and TRPC channels for Podocin. Both the MEC-2-dependent activation of mechanosensation and the Podocin-dependent activation of TRPC channels require cholesterol. Thus, MEC-2, Podocin, and probably many other PHB-domain proteins by binding to themselves, cholesterol, and target proteins regulate the formation and function of large protein-cholesterol supercomplexes in the plasma membrane.
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Affiliation(s)
- Tobias B. Huber
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | - Bernhard Schermer
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | | | - Martin Höhne
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | - Malte Bartram
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | - Andrea Calixto
- Department of Biological Sciences, Columbia University, New York, NY 10027-6902
| | - Henning Hagmann
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | - Christian Reinhardt
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
- University Hospital Münster, D-48129 Münster, Germany
| | - Fabienne Koos
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, 93053 Regensburg, Germany
| | - Elena Shirokova
- Department of Molecular Genetics, German Institute of Human Nutrition, 14558 Nuthetal, Germany
| | - Dietmar Krautwurst
- Department of Molecular Genetics, German Institute of Human Nutrition, 14558 Nuthetal, Germany
| | | | - Matias Simons
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | | | - Dontscho Kerjaschki
- **Department of Pathology, University of Vienna, A-1010 Vienna, Austria; and
| | - Christoph Thiele
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Gerd Walz
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
| | - Martin Chalfie
- Department of Biological Sciences, Columbia University, New York, NY 10027-6902
- To whom correspondence may be addressed at:
Department of Biological Sciences, Columbia University, 1012 Fairchild Center, M.C. 2446 New York, NY 10027. E-mail:
| | - Thomas Benzing
- *Renal Division, University Hospital Freiburg, 79106 Freiburg, Germany
- To whom correspondence may be addressed at:
Renal Division, University Hospital Freiburg, Hugstetterstrasse 55, 79106 Freiburg, Germany. E-mail:
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Guizouarn H, Martial S, Borgese F. [Unexpected properties of red blood cell anion exchanger: The fish lesson]. Med Sci (Paris) 2006; 22:824-5. [PMID: 17026933 DOI: 10.1051/medsci/20062210824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Abstract
The red cell membrane is one of the best known membranes in terms of structure, function and genetic disorders. As any plasma membrane it mediates transport functions. It also provides the erythrocytes with their resilience and deformability. Many of the proteins and the genes performing these functions are known in great detail, although some disease-responsible genes are yet to be elucidated. Basic knowledge has shed light on important groups of genetic disorders. The latter include (i) the disorders of the red cell mechanics: hereditary spherocytosis, hereditary elliptocytosis and poikilocytosis, and (ii) the disorders of the passive flux of the monovalent cations across the membrane: the stomacytoses and allied conditions. Reciprocally, many information have come from genetics abnormalities. We will review the mutation-disease relationship. A number of points will be underscored: widespread weak alleles modulate the expression of the SPTA1 gene, encoding the alpha-chain of spectrin; mutations in the anion exchanger can give rise to an array of distinct nosological entities, including a renal condition; splenectomy is banned in the stomatocytoses; a variety of stomatocyosis is part of a pleiotropic syndrome that may includes perinatal fetal liquid effusions. The diagnosis, follow-up and treatment of the involved diseases have gradually improved.
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Affiliation(s)
- Jean Delaunay
- AP-HP, Hôpital de Bicêtre, Service d'Hématologie, INSERM Unité 779, Faculté de Médecine Paris-Sud, Le Kremlin-Bicêtre, France.
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Bruce L. Mutations in band 3 and cation leaky red cells. Blood Cells Mol Dis 2006; 36:331-6. [PMID: 16531080 DOI: 10.1016/j.bcmd.2006.01.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2006] [Accepted: 01/11/2006] [Indexed: 11/16/2022]
Abstract
We have recently shown that amino acid substitutions in the membrane domain of band 3 (anion exchanger 1, SLC4A1) are associated with hereditary stomatocytosis (HSt), a red cell condition in which the cells leak sodium and potassium ions. These substitutions appear to convert band 3 from an anion exchanger into a cation channel. In this review, I will first give some background on the structure and function of normal band 3 and describe our findings in red cells from HSt patients. Then I will compare the properties of the HSt band 3 to those of Southeast Asian Ovalocytosis (SAO) band 3 and discuss the implications for the structure of band 3, the quality control of protein expression in red cells and the cation permeability of normal human red cells.
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Affiliation(s)
- Lesley Bruce
- Bristol Institute for Transfusion Sciences, National Blood Service, Southmead, Bristol BS10 5ND, UK.
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Edqvist J, Blomqvist K. Fusion and fission, the evolution of sterol carrier protein-2. J Mol Evol 2006; 62:292-306. [PMID: 16501878 DOI: 10.1007/s00239-005-0086-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2005] [Accepted: 10/21/2005] [Indexed: 11/28/2022]
Abstract
Sterol carrier protein-2 (SCP-2) is an intracellular, small, basic protein domain that in vitro enhances the transfer of lipids between membranes. It is expressed in bacteria, archaea, and eukaryotes. There are five human genes, HSD17B4, SCPX, HSDL2 STOML1, and C20orf79, which encode SCP-2. HSD17B4, SCPX, HSDL2, and STOML1 encode fusion proteins with SCP-2 downstream of another protein domain, whereas C20orf79 encodes an unfused SCP-2. We have extracted SCP-2 domains from databases and analyzed the evolution of the eukaryotic SCP-2. We show that SCPX and HSDL2 are present in most animals from Cnidaria to Chordata. STOML1 are present in nematodes and more advanced animals. HSD17B4 which encodes a D-bifunctional protein (DBP) with domains for D-3-hydroxyacyl-CoA dehydrogenase, enoyl-CoA hydratase, and SCP-2 are found in animals from insects to mammals and also in fungi. Nematodes, amoebas, ciliates, apicomplexans, and oomycetes express an alternative DBP with the SCP-2 domain directly connected to the D-3-hydroxyacyl-CoA dehydrogenase. This fusion has not been retained in plant genomes, which solely express unfused SCP-2 domains. Proteins carrying unfused SCP-2 domains are also encoded in bacteria, archaea, ciliates, fungi, insects, nematodes, and vertebrates. Our results indicate that the fusion between D-3-hydroxyacyl-CoA dehydrogenase and SCP-2 was formed early during eukaryotic evolution. There have since been several gene fission events where genes encoding unfused SCP-2 domains have been formed, as well as gene fusion events placing the SCP-2 domain in novel protein domain contexts.
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Affiliation(s)
- Johan Edqvist
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences, Uppsala.
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Rubin J, Rubin C, Jacobs CR. Molecular pathways mediating mechanical signaling in bone. Gene 2006; 367:1-16. [PMID: 16361069 PMCID: PMC3687520 DOI: 10.1016/j.gene.2005.10.028] [Citation(s) in RCA: 297] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2005] [Accepted: 10/03/2005] [Indexed: 12/26/2022]
Abstract
Bone tissue has the capacity to adapt to its functional environment such that its morphology is "optimized" for the mechanical demand. The adaptive nature of the skeleton poses an interesting set of biological questions (e.g., how does bone sense mechanical signals, what cells are the sensing system, what are the mechanical signals that drive the system, what receptors are responsible for transducing the mechanical signal, what are the molecular responses to the mechanical stimuli). Studies of the characteristics of the mechanical environment at the cellular level, the forces that bone cells recognize, and the integrated cellular responses are providing new information at an accelerating speed. This review first considers the mechanical factors that are generated by loading in the skeleton, including strain, stress and pressure. Mechanosensitive cells placed to recognize these forces in the skeleton, osteoblasts, osteoclasts, osteocytes and cells of the vasculature are reviewed. The identity of the mechanoreceptor(s) is approached, with consideration of ion channels, integrins, connexins, the lipid membrane including caveolar and non-caveolar lipid rafts and the possibility that altering cell shape at the membrane or cytoskeleton alters integral signaling protein associations. The distal intracellular signaling systems on-line after the mechanoreceptor is activated are reviewed, including those emanating from G-proteins (e.g., intracellular calcium shifts), MAPKs, and nitric oxide. The ability to harness mechanical signals to improve bone health through devices and exercise is broached. Increased appreciation of the importance of the mechanical environment in regulating and determining the structural efficacy of the skeleton makes this an exciting time for further exploration of this area.
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Affiliation(s)
- Janet Rubin
- Department of Medicine, VAMC and Emory University School of Medicine, Atlanta GA, VAMC-151, 1670 Clairmont Rd, Decatur, GA 30033, USA.
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Bruce LJ, Robinson HC, Guizouarn H, Borgese F, Harrison P, King MJ, Goede JS, Coles SE, Gore DM, Lutz HU, Ficarella R, Layton DM, Iolascon A, Ellory JC, Stewart GW. Monovalent cation leaks in human red cells caused by single amino-acid substitutions in the transport domain of the band 3 chloride-bicarbonate exchanger, AE1. Nat Genet 2005; 37:1258-63. [PMID: 16227998 DOI: 10.1038/ng1656] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2005] [Accepted: 08/17/2005] [Indexed: 11/09/2022]
Abstract
We identified 11 human pedigrees with dominantly inherited hemolytic anemias in both the hereditary stomatocytosis and spherocytosis classes. Affected individuals in these families had an increase in membrane permeability to Na and K that is particularly marked at 0 degrees C. We found that disease in these pedigrees was associated with a series of single amino-acid substitutions in the intramembrane domain of the erythrocyte band 3 anion exchanger, AE1. Anion movements were reduced in the abnormal red cells. The 'leak' cation fluxes were inhibited by SITS, dipyridamole and NS1652, chemically diverse inhibitors of band 3. Expression of the mutated genes in Xenopus laevis oocytes induced abnormal Na and K fluxes in the oocytes, and the induced Cl transport was low. These data are consistent with the suggestion that the substitutions convert the protein from an anion exchanger into an unregulated cation channel.
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Affiliation(s)
- Lesley J Bruce
- Bristol Institute for Transfusion Sciences, National Blood Service, Southmead, Bristol BS10 5ND, UK
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Rees DC, Iolascon A, Carella M, O'marcaigh AS, Kendra JR, Jowitt SN, Wales JK, Vora A, Makris M, Manning N, Nicolaou A, Fisher J, Mann A, Machin SJ, Clayton PT, Gasparini P, Stewart GW. Stomatocytic haemolysis and macrothrombocytopenia (Mediterranean stomatocytosis/macrothrombocytopenia) is the haematological presentation of phytosterolaemia. Br J Haematol 2005; 130:297-309. [PMID: 16029460 DOI: 10.1111/j.1365-2141.2005.05599.x] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phytosterolaemia (sitosterolaemia) is a recessively inherited metabolic condition in which the absorption of both cholesterol and plant-derived cholesterol-like molecules at the gut is unselective and unrestricted. In haematology, Mediterranean stomatocytosis or Mediterranean macrothrombocytopenia is a poorly understood haematological condition that combines stomatocytic haemolysis with the presence of very large platelets. Five pedigrees showing this haematology were identified. Gas chromatography mass spectrometry (GC-MS) showed that all of the patients with this highly specific haematology had grossly elevated levels of phytosterols in the blood, diagnostic of phytosterolaemia. All showed mutations in the ABCG5 and ABCG8 previously linked to phytosterolaemia. Three pedigrees showed five new mutations, while two pedigrees showed the common W361X mutation in ABCG8. We draw the following four conclusions: (i) that Mediterranean stomatocytosis/macrothrombocytopenia is caused by an excess of phytosterols in the blood; (ii) that phytosterolaemia, which does not respond to standard statin treatment, can be diagnosed via the distinctive haematology described here, even when the cholesterol is normal; (iii) that phytosterolaemia should be considered in the differential diagnosis of all patients with large platelets; and (iv) that the platelet size should be noted in patients with hypercholesterolaemia.
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Affiliation(s)
- David C Rees
- Sheffield Children's Hospital, Royal Hallamshire Hospital, Sheffield, UK
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