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Sinclair M, Stein RA, Sheehan JH, Hawes EM, O’Brien RM, Tajkhorshid E, Claxton DP. Integrative analysis of pathogenic variants in glucose-6-phosphatase based on an AlphaFold2 model. PNAS NEXUS 2024; 3:pgae036. [PMID: 38328777 PMCID: PMC10849595 DOI: 10.1093/pnasnexus/pgae036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 01/09/2024] [Indexed: 02/09/2024]
Abstract
Mediating the terminal reaction of gluconeogenesis and glycogenolysis, the integral membrane protein glucose-6-phosphate catalytic subunit 1 (G6PC1) regulates hepatic glucose production by catalyzing hydrolysis of glucose-6-phosphate (G6P) within the lumen of the endoplasmic reticulum. Consistent with its vital contribution to glucose homeostasis, inactivating mutations in G6PC1 causes glycogen storage disease (GSD) type 1a characterized by hepatomegaly and severe hypoglycemia. Despite its physiological importance, the structural basis of G6P binding to G6PC1 and the molecular disruptions induced by missense mutations within the active site that give rise to GSD type 1a are unknown. In this study, we determine the atomic interactions governing G6P binding as well as explore the perturbations imposed by disease-linked missense variants by subjecting an AlphaFold2 G6PC1 structural model to molecular dynamics simulations and in silico predictions of thermodynamic stability validated with robust in vitro and in situ biochemical assays. We identify a collection of side chains, including conserved residues from the signature phosphatidic acid phosphatase motif, that contribute to a hydrogen bonding and van der Waals network stabilizing G6P in the active site. The introduction of GSD type 1a mutations modified the thermodynamic landscape, altered side chain packing and substrate-binding interactions, and induced trapping of catalytic intermediates. Our results, which corroborate the high quality of the AF2 model as a guide for experimental design and to interpret outcomes, not only confirm the active-site structural organization but also identify previously unobserved mechanistic contributions of catalytic and noncatalytic side chains.
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Affiliation(s)
- Matt Sinclair
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Richard A Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
- Center for Applied Artificial Intelligence in Protein Dynamics, Vanderbilt University, Nashville, TN 37240, USA
| | - Jonathan H Sheehan
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
- Division of Infectious Diseases, Department of Internal Medicine, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Emily M Hawes
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Richard M O’Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Emad Tajkhorshid
- Theoretical and Computational Biophysics Group, NIH Center for Macromolecular Modeling and Visualization, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Department of Biochemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
- Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Derek P Claxton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
- Center for Applied Artificial Intelligence in Protein Dynamics, Vanderbilt University, Nashville, TN 37240, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37240, USA
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Wang Z, Zhao R, Jia X, Li X, Ma L, Fu H. Three novel SLC37A4 variants in glycogen storage disease type 1b and a literature review. J Int Med Res 2023; 51:3000605231216633. [PMID: 38087503 PMCID: PMC10718061 DOI: 10.1177/03000605231216633] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 11/08/2023] [Indexed: 12/18/2023] Open
Abstract
Glycogen storage disease type 1b (GSD1b) is a rare genetic disorder, resulting from mutations in the SLC37A4 gene located on chromosome 11q23.3. Although the SLC37A4 gene has been identified as the pathogenic gene for GSD1b, the complete variant spectrum of this gene remains to be fully elucidated. In this study, we present three patients diagnosed with GSD1b through genetic testing. We detected five variants of the SLC37A4 gene in these three patients, with three of these mutations (p. L382Pfs*15, p. G117fs*28, and p. T312Sfs*13) being novel variants not previously reported in the literature. We also present a literature review and general overview of the currently reported SLC37A4 gene variants. Our study expands the mutation spectrum of SLC37A4, which may help enable genetic testing to facilitate prompt diagnosis, appropriate intervention, and genetic counseling for affected families.
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Affiliation(s)
- Zhuolin Wang
- Department of Gastroenterology, Hebei Children's Hospital, 133 Jianhua South Street, Shijiazhuang 050031, Hebei Province, China
| | - Ruiqin Zhao
- Department of Gastroenterology, Hebei Children's Hospital, 133 Jianhua South Street, Shijiazhuang 050031, Hebei Province, China
| | - Xiaoyun Jia
- Department of Gastroenterology, Hebei Children's Hospital, 133 Jianhua South Street, Shijiazhuang 050031, Hebei Province, China
| | - Xiaolei Li
- Department of Gastroenterology, Hebei Children's Hospital, 133 Jianhua South Street, Shijiazhuang 050031, Hebei Province, China
| | - Li Ma
- Department of Neonatology, Hebei Children's Hospital, 133 Jianhua South Street, Shijiazhuang 050031, Hebei Province, China
| | - Haiyan Fu
- Department of Gastroenterology, Hebei Children's Hospital, 133 Jianhua South Street, Shijiazhuang 050031, Hebei Province, China
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3
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Sinclair M, Stein RA, Sheehan JH, Hawes EM, O'Brien RM, Tajkhorshid E, Claxton DP. Molecular mechanisms of catalytic inhibition for active site mutations in glucose-6-phosphatase catalytic subunit 1 linked to glycogen storage disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.13.532485. [PMID: 36993754 PMCID: PMC10054992 DOI: 10.1101/2023.03.13.532485] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Mediating the terminal reaction of gluconeogenesis and glycogenolysis, the integral membrane protein G6PC1 regulates hepatic glucose production by catalyzing hydrolysis of glucose-6-phosphate (G6P) within the lumen of the endoplasmic reticulum. Consistent with its vital contribution to glucose homeostasis, inactivating mutations in G6PC1 cause glycogen storage disease (GSD) type 1a characterized by hepatomegaly and severe hypoglycemia. Despite its physiological importance, the structural basis of G6P binding to G6PC1 and the molecular disruptions induced by missense mutations within the active site that give rise to GSD type 1a are unknown. Exploiting a computational model of G6PC1 derived from the groundbreaking structure prediction algorithm AlphaFold2 (AF2), we combine molecular dynamics (MD) simulations and computational predictions of thermodynamic stability with a robust in vitro screening platform to define the atomic interactions governing G6P binding as well as explore the energetic perturbations imposed by disease-linked variants. We identify a collection of side chains, including conserved residues from the signature phosphatidic acid phosphatase motif, that contribute to a hydrogen bonding and van der Waals network stabilizing G6P in the active site. Introduction of GSD type 1a mutations into the G6PC1 sequence elicits changes in G6P binding energy, thermostability and structural properties, suggesting multiple pathways of catalytic impairment. Our results, which corroborate the high quality of the AF2 model as a guide for experimental design and to interpret outcomes, not only confirm active site structural organization but also suggest novel mechanistic contributions of catalytic and non-catalytic side chains.
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4
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Veiga-da-Cunha M, Wortmann SB, Grünert SC, Van Schaftingen E. Treatment of the Neutropenia Associated with GSD1b and G6PC3 Deficiency with SGLT2 Inhibitors. Diagnostics (Basel) 2023; 13:diagnostics13101803. [PMID: 37238286 DOI: 10.3390/diagnostics13101803] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Revised: 05/12/2023] [Accepted: 05/17/2023] [Indexed: 05/28/2023] Open
Abstract
Glycogen storage disease type Ib (GSD1b) is due to a defect in the glucose-6-phosphate transporter (G6PT) of the endoplasmic reticulum, which is encoded by the SLC37A4 gene. This transporter allows the glucose-6-phosphate that is made in the cytosol to cross the endoplasmic reticulum (ER) membrane and be hydrolyzed by glucose-6-phosphatase (G6PC1), a membrane enzyme whose catalytic site faces the lumen of the ER. Logically, G6PT deficiency causes the same metabolic symptoms (hepatorenal glycogenosis, lactic acidosis, hypoglycemia) as deficiency in G6PC1 (GSD1a). Unlike GSD1a, GSD1b is accompanied by low neutrophil counts and impaired neutrophil function, which is also observed, independently of any metabolic problem, in G6PC3 deficiency. Neutrophil dysfunction is, in both diseases, due to the accumulation of 1,5-anhydroglucitol-6-phosphate (1,5-AG6P), a potent inhibitor of hexokinases, which is slowly formed in the cells from 1,5-anhydroglucitol (1,5-AG), a glucose analog that is normally present in blood. Healthy neutrophils prevent the accumulation of 1,5-AG6P due to its hydrolysis by G6PC3 following transport into the ER by G6PT. An understanding of this mechanism has led to a treatment aimed at lowering the concentration of 1,5-AG in blood by treating patients with inhibitors of SGLT2, which inhibits renal glucose reabsorption. The enhanced urinary excretion of glucose inhibits the 1,5-AG transporter, SGLT5, causing a substantial decrease in the concentration of this polyol in blood, an increase in neutrophil counts and function and a remarkable improvement in neutropenia-associated clinical signs and symptoms.
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Affiliation(s)
- Maria Veiga-da-Cunha
- Metabolic Research Group, de Duve Institute and UCLouvain, B-1200 Brussels, Belgium
| | - Saskia B Wortmann
- University Children's Hospital, Paracelsus Medical University, 5020 Salzburg, Austria
- Amalia Children's Hospital, Radboudumc, 6525 Nijmegen, The Netherlands
| | - Sarah C Grünert
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Center, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
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Grünert SC, Derks TGJ, Adrian K, Al-Thihli K, Ballhausen D, Bidiuk J, Bordugo A, Boyer M, Bratkovic D, Brunner-Krainz M, Burlina A, Chakrapani A, Corpeleijn W, Cozens A, Dawson C, Dhamko H, Milosevic MD, Eiroa H, Finezilber Y, Moura de Souza CF, Garcia-Jiménez MC, Gasperini S, Haas D, Häberle J, Halligan R, Fung LH, Hörbe-Blindt A, Horka LM, Huemer M, Uçar SK, Kecman B, Kilavuz S, Kriván G, Lindner M, Lüsebrink N, Makrilkakis K, Mei-Kwun Kwok A, Maier EM, Maiorana A, McCandless SE, Mitchell JJ, Mizumoto H, Mundy H, Ochoa C, Pierce K, Fraile PQ, Regier D, Rossi A, Santer R, Schuman HC, Sobieraj P, Spenger J, Spiegel R, Stepien KM, Tal G, Tanšek MZ, Torkar AD, Tchan M, Thyagu S, Schrier Vergano SA, Vucko E, Weinhold N, Zsidegh P, Wortmann SB. Efficacy and safety of empagliflozin in glycogen storage disease type Ib: Data from an international questionnaire. Genet Med 2022; 24:1781-1788. [PMID: 35503103 DOI: 10.1016/j.gim.2022.04.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/31/2022] [Accepted: 04/01/2022] [Indexed: 01/10/2023] Open
Abstract
PURPOSE This paper aims to report collective information on safety and efficacy of empagliflozin drug repurposing in individuals with glycogen storage disease type Ib (GSD Ib). METHODS This is an international retrospective questionnaire study on the safety and efficacy of empagliflozin use for management of neutropenia/neutrophil dysfunction in patients with GSD Ib, conducted among the respective health care providers from 24 countries across the globe. RESULTS Clinical data from 112 individuals with GSD Ib were evaluated, representing a total of 94 treatment years. The median age at start of empagliflozin treatment was 10.5 years (range = 0-38 years). Empagliflozin showed positive effects on all neutrophil dysfunction-related symptoms, including oral and urogenital mucosal lesions, recurrent infections, skin abscesses, inflammatory bowel disease, and anemia. Before initiating empagliflozin, most patients with GSD Ib were on G-CSF (94/112; 84%). At the time of the survey, 49 of 89 (55%) patients previously treated with G-CSF had completely stopped G-CSF, and another 15 (17%) were able to reduce the dose. The most common adverse event during empagliflozin treatment was hypoglycemia, occurring in 18% of individuals. CONCLUSION Empagliflozin has a favorable effect on neutropenia/neutrophil dysfunction-related symptoms and safety profile in individuals with GSD Ib.
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Affiliation(s)
- Sarah C Grünert
- Department of General Pediatrics, Adolescent Medicine and Neonatology, Medical Centre-University of Freiburg, Faculty of Medicine, Freiburg, Germany.
| | - Terry G J Derks
- Section of Metabolic Diseases, Beatrix Children's Hospital, University Medical Center of Groningen, University of Groningen, Groningen, The Netherlands
| | - Katarina Adrian
- Department of Pediatrics, Queen Silvias Childrens Hospital, Sahlgrenska University Hospital, Göteborg, Sweden
| | - Khalid Al-Thihli
- Genetic and Developmental Medicine Clinic, Sultan Qaboos University Hospital, Muscat, Oman
| | - Diana Ballhausen
- Pediatric Metabolic Unit, Pediatrics, Woman-Mother-Child Department, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Joanna Bidiuk
- Department of Internal Medicine, Hypertension and Vascular Diseases, Medical University of Warsaw, Warsaw, Poland
| | - Andrea Bordugo
- Inherited Metabolic Disease Unit, Pediatric Clinic C, Woman and Child Department, Azienda Ospedaliera Università Integrata, Verona, Italy
| | - Monica Boyer
- Division of Metabolic Disorders, CHOC Children's Hospital, Orange, CA
| | - Drago Bratkovic
- Metabolic Clinic, Women's and Children's Hospital, North Adelaide, South Australia, Australia
| | | | - Alberto Burlina
- Division of Inherited Metabolic Diseases, Department of Diagnostic Services, University Hospital, Padua, Italy
| | - Anupam Chakrapani
- Department of Metabolic Medicine, Great Ormond Street Hospital, London, United Kingdom
| | - Willemijn Corpeleijn
- Department of Pediatrics, Division of Metabolic Disorders, Emma Children's Hospital, Gastroenterology, Endocrinology & Metabolism, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Alison Cozens
- Royal Hospital for Children and Young People, Edinburgh, United Kingdom
| | - Charlotte Dawson
- Department of Endocrinology, Diabetes and Metabolism, University Hospitals Birmingham, Birmingham, United Kingdom
| | - Helena Dhamko
- Division of Medical Oncology and Hematology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Maja Djordjevic Milosevic
- Metabolic and Genetic Department, Mother and Child Health Care Institute of Serbia "Dr Vukan Čupić", Belgrade, Serbia
| | - Hernan Eiroa
- Servicio de Errores Congenitos del Metabolismo, Hospital de Pediatria "J.P. Garrahan", Buenos Aires, Argentina
| | - Yael Finezilber
- Metabolic Diseases Unit and Internal Medicine Department A, Sheba Medical Center, Ramat Gan, Israel
| | | | | | - Serena Gasperini
- Metabolic Rare Diseases Unit, Paediatric Department, San Gerardo Hospital, Monza, Italy
| | - Dorothea Haas
- Center for Child and Adolescent Medicine, Division of Child Neurology and Metabolic Medicine, University Hospital Heidelberg, Heidelberg, Germany
| | - Johannes Häberle
- Division of Metabolism and Children`s Research Center, University Children's Hospital Zurich, Zürich, Switzerland
| | - Rebecca Halligan
- Department of Metabolic Medicine, The Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Law Hiu Fung
- Department of Pediatrics and Adolescent Medicine, Queen Mary Hospital, Hong Kong Island, Hong Kong
| | | | - Laura Maria Horka
- Department of Endocrinology, Diabetology and Clinical Nutrition, University Hospital Zurich and University of Zurich, Zurich, Switzerland
| | - Martina Huemer
- Division of Metabolism and Children`s Research Center, University Children's Hospital Zurich, Zürich, Switzerland; Department of Paediatrics, University Children's Hospital Basel and University of Basel, Basel, Switzerland
| | - Sema Kalkan Uçar
- Division of Metabolism and Nutrition, Department of Pediatrics, Ege University Children's Hospital, Izmir, Turkey
| | - Bozica Kecman
- Metabolic and Genetic Department, Mother and Child Health Care Institute of Serbia "Dr Vukan Čupić", Belgrade, Serbia
| | - Sebile Kilavuz
- Division of Pediatric Metabolism, Department of Pediatrics, University of Health Sciences, Van Training and Research Hospital, Van, Turkey
| | - Gergely Kriván
- Department for Pediatric Hematology and Hemopoietic Stem Cell Transplantation, Central Hospital of Southern Pest National Institute of Hematology and Infectious Diseases, Budapest, Hungary
| | - Martin Lindner
- Department of Pediatric Neurology, University Children's Hospital Frankfurt, Frankfurt, Germany
| | - Natalia Lüsebrink
- Department of Pediatric Neurology, University Children's Hospital Frankfurt, Frankfurt, Germany
| | - Konstantinos Makrilkakis
- First Department of Propaedeutic Internal Medicine, National and Kapodistrian University of Athens Medical School, Laiko General Hospital, Athens, Greece
| | - Anne Mei-Kwun Kwok
- Department of Pediatrics and Adolescent Medicine, Hong Kong Children's Hospital, Hong Kong
| | - Esther M Maier
- Section of Inborn Errors of Metabolism, Dr. von Hauner Children's Hospital, University of Munich, Munich, Germany
| | - Arianna Maiorana
- Division of Metabolism, Department of Pediatric Subspecialties, Ospedale Pediatrico Bambino Gesù, Istituti di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - Shawn E McCandless
- Department of Pediatrics, University of Colorado School of Medicine, Aurora, CO; Department of Genetics and Metabolism, Children's Hospital Colorado, Aurora, CO
| | - John James Mitchell
- Division of Pediatric Endocrinology, McGill University Health Center, Montreal, Quebec, Canada
| | - Hiroshi Mizumoto
- Department of Pediatrics, Tazuke Kofukai Medical Research Institute, Kitano Hospital, Osaka, Japan
| | - Helen Mundy
- Evelina Children's Hospital, London, United Kingdom
| | - Carlos Ochoa
- Department of Pediatrics, Complejo Asistencial de Zamora, Zamora, Spain
| | | | - Pilar Quijada Fraile
- Reference Center for Inherited Metabolic Disorders, Department of Pediatrics, Hospital Universitario 12 de Octubre, Madrid, Spain
| | - Debra Regier
- Genetics and Metabolism, Children's National Hospital, Washington DC
| | - Alessandro Rossi
- Section of Paediatrics, Department of Translational Medicine, University of Naples "Federico II", Naples, Italy
| | - René Santer
- Department of Pediatrics, University Medical Center Eppendorf, Hamburg, Germany
| | | | - Piotr Sobieraj
- Department of Internal Medicine, Hypertension and Vascular Diseases, Medical University of Warsaw, Warsaw, Poland
| | | | - Ronen Spiegel
- Pediatric Department B, Emek Medical Center, Afula, Rappaport School of Medicine, Technion, Haifa, Israel
| | - Karolina M Stepien
- Adult Inherited Metabolic Diseases, Salford Royal NHS Foundation Trust, Salford, United Kingdom
| | - Galit Tal
- Metabolic Clinic, Ruth Rappaport Children's Hospital, Rambam Health Care Campus, Haifa, Israel
| | - Mojca Zerjav Tanšek
- University Children's Hospital, Department of Endocrinology, Diabetes and Metabolism, Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Ana Drole Torkar
- University Children's Hospital, Department of Endocrinology, Diabetes and Metabolism, Ljubljana University Medical Centre, Ljubljana, Slovenia
| | - Michel Tchan
- Department of Genetic Medicine, Westmead Hospital, Sydney, New South Wales, Australia; Sydney Medical School, University of Sydney, Sydney, New South Wales, Australia
| | - Santhosh Thyagu
- Division of Medical Oncology and Hematology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | | | - Erika Vucko
- Division of Genetics, Birth Defects, and Metabolism, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL
| | - Natalie Weinhold
- Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Department of Pediatric Gastroenterology, Nephrology and Metabolic Diseases, Center of Chronically Sick Children, Berlin, Germany
| | - Petra Zsidegh
- Newborn Screening and Metabolic Centre, 1(st) Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Saskia B Wortmann
- University Children's Hospital Salzburg, Salzburg, Austria; Amalia Children's Hospital, Nijmegen, The Netherlands
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Gong YZ, Zhong XM, Zou JZ. Infliximab treatment of glycogenosis Ib with Crohn's-like enterocolitis: A case report. World J Clin Cases 2021; 9:5280-5286. [PMID: 34307579 PMCID: PMC8283598 DOI: 10.12998/wjcc.v9.i19.5280] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/11/2021] [Accepted: 04/25/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Glycogen storage disease type Ib (GSD-Ib) is a glycogen metabolism disorder that leads to the manifestations of inflammatory bowel disease (IBD), especially Crohn’s disease (CD)-like colitis. Although biological agents are effective for treating CD, their application in the treatment of GSD-Ib with CD-like colitis has been rarely reported.
CASE SUMMARY A 13-year-old Han male was diagnosed with GSD-Ib with CD. The patient was treated with granulocyte colony-stimulating factor. When he had symptoms of CD-like colitis, he was continuously pumped with enteral nutrition and administered oral mesalazine for 2 wk; however, the symptoms did not improve significantly. Hence, infliximab (IFX) was administered. Hitherto, the patient has been followed up for 1 year, and no clinical manifestations have been observed. After 6 mo of treatment (fifth IFX treatment), the disease activity index and all inflammatory indexes decreased, and a review of the colonoscopy data showed that the ulcers appeared smooth.
CONCLUSION In this study, the patient was successfully treated with IFX. In cases of GSD-Ib, IBD should be highly considered.
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Affiliation(s)
- You-Zhe Gong
- Gastroenterology Department, Capital Institute of Pediatrics, Beijing 100020, China
| | - Xue-Mei Zhong
- Gastroenterology Department, Capital Institute of Pediatrics, Beijing 100020, China
| | - Ji-Zhen Zou
- Pathology Department, Capital Institute of Pediatrics, Beijing 100020, China
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Su W, Yu Y, Xu X, Wang XQ, Huang JB, Xu CD, Xiao Y. Valuable clinical indicators for identifying infantile-onset inflammatory bowel disease patients with monogenic diseases. World J Gastroenterol 2021; 27:92-106. [PMID: 33505153 PMCID: PMC7789064 DOI: 10.3748/wjg.v27.i1.92] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/02/2020] [Accepted: 12/10/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Infantile-onset inflammatory bowel disease (IO-IBD) occurs in very young children and causes severe clinical manifestations, which has poor responses to traditional inflammatory bowel disease (IBD) treatments. At present, there are no simple and reliable laboratory indicators for early screening IO-IBD patients, especially those in whom the disease is caused by monogenic diseases.
AIM To search for valuable indicators for early identifying IO-IBD patients, especially those in whom the disease is caused by monogenic diseases.
METHODS A retrospective analysis was performed in 73 patients with IO-IBD admitted to our hospital in the past 5 years. Based on the next-generation sequencing results, they were divided into a monogenic IBD group (M-IBD) and a non-monogenic IBD group (NM-IBD). Forty age-matched patients with allergic proctocolitis (AP) were included in a control group. The clinical manifestations and the inflammatory factors in peripheral blood were evaluated. Logistic regression analysis and receiver operating characteristic (ROC) curve analysis were used to identify the screening factors and cut-off values of IO-IBD as well as monogenic IO-IBD, respectively.
RESULTS Among the 44 M-IBD patients, 35 carried IL-10RA mutations, and the most common mutations were c.301C>T (p.R101W, 30/70) and the c.537G>A (p.T179T, 17/70). Patients with higher serum tumor necrosis factor (TNF)-α value were more likely to have IBD [odds ratio (OR) = 1.25, 95% confidence interval (CI): 1.05-1.50, P = 0.013], while higher serum albumin level was associated with lower risk of IBD (OR = 0.86, 95%CI: 0.74-1.00, P = 0.048). The cut-off values of TNF-α and albumin were 17.40 pg/mL (sensitivity: 0.78; specificity: 0.88) and 36.50 g/L (sensitivity: 0.80; specificity: 0.90), respectively. The increased ferritin level was indicative of a genetic mutation in IO-IBD patients. Its cut-off value was 28.20 ng/mL (sensitivity: 0.93; specificity: 0.92). When interleukin (IL)-10 level was higher than 33.05 pg/mL (sensitivity: 1.00; specificity: 0.84), or the onset age was earlier than 0.21 mo (sensitivity: 0.82; specificity: 0.94), the presence of disease-causing mutations in IL-10RA in IO-IBD patients was strongly suggested.
CONCLUSION Serum TNF-α and albumin level could differentiate IO-IBD patients from allergic proctocolitis patients, and serum ferritin and IL-10 levels are useful indicators for early diagnosing monogenic IO-IBD.
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Affiliation(s)
- Wen Su
- Department of Pediatrics, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Yi Yu
- Department of Pediatrics, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Xu Xu
- Department of Pediatrics, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Xin-Qiong Wang
- Department of Pediatrics, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jie-Bin Huang
- Department of Pediatrics, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Chun-Di Xu
- Department of Pediatrics, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Yuan Xiao
- Department of Pediatrics, Ruijin Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
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8
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Xu Q, Tang H, Duan L, Zuo X, Shi X, Li Y, Zhao H, Zhang H. A novel SLC37A4 missense mutation in GSD-Ib without hepatomegaly causes enhanced leukocytes endoplasmic reticulum stress and apoptosis. Mol Genet Genomic Med 2020; 9:e1568. [PMID: 33280276 PMCID: PMC7963412 DOI: 10.1002/mgg3.1568] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 11/08/2020] [Accepted: 11/16/2020] [Indexed: 11/19/2022] Open
Abstract
Background Glycogen storage disease (GSD) type Ib is an autosomal recessive disease caused by defects of glucose‐6‐phosphate transporter (G6PT), encoded by the SLC37A4 gene. To date, over 100 mutations have been revealed in the SLC37A4 gene. GSD‐Ib patients manifest a metabolic phenotype of impaired blood glucose homeostasis and also carry the additional complications of neutropenia and myeloid dysfunction. Methods Here, we present two daughters with an initial diagnosis of gout in a Chinese consanguineous family. Whole‐exome sequencing was performed to identify the mutations. The mechanism of leukocytopenia was investigated. Results Whole‐exome sequencing analysis of the proband identified a novel homozygous p.P119L mutation in SLC37A4, leading to a diagnosis of GSD‐Ib. We found that the potential pathogenic p.P119L mutation leads to an unusual phenotype characterized by gout at onset, and GSD‐Ib arising from this variant also manifests multiple metabolic abnormalities, leukocytopenia, and anemia, but no hepatomegaly. The leukocytes from the proband showed increased mRNA levels of sXBP‐1, BIP, and CHOP genes in the unfolded protein response pathway, and enhanced Bax mRNA and caspase‐3 activity, which might contribute to leukocytopenia. Conclusion Our findings broaden the variation spectrum of SLC37A4 and suggest no strict genotype–phenotype correlations in GSD‐Ib patients.
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Affiliation(s)
- Qianyun Xu
- Department of Rheumatology, Xiangya Hospital, Central South University, Changsha, China
| | - Haiyan Tang
- Department of Medical Genetics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Liping Duan
- Department of Rheumatology, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaoxia Zuo
- Department of Rheumatology, Xiangya Hospital, Central South University, Changsha, China
| | - Xiaoliu Shi
- Department of Medical Genetics, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Yisha Li
- Department of Rheumatology, Xiangya Hospital, Central South University, Changsha, China.,Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, China
| | - Hongjun Zhao
- Department of Rheumatology, Xiangya Hospital, Central South University, Changsha, China
| | - Huali Zhang
- Department of Rheumatology, Xiangya Hospital, Central South University, Changsha, China.,Department of Pathophysiology, Xiangya School of Medicine, Central South University, Changsha, China.,Sepsis Translational Medicine Key Laboratory of Hunan, Central South University, Changsha, China
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9
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Grünert SC, Elling R, Maag B, Wortmann SB, Derks TGJ, Hannibal L, Schumann A, Rosenbaum-Fabian S, Spiekerkoetter U. Improved inflammatory bowel disease, wound healing and normal oxidative burst under treatment with empagliflozin in glycogen storage disease type Ib. Orphanet J Rare Dis 2020; 15:218. [PMID: 32838757 PMCID: PMC7446198 DOI: 10.1186/s13023-020-01503-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 08/09/2020] [Indexed: 01/05/2023] Open
Abstract
Background Glycogen storage disease type Ib (GSD Ib) is a rare inborn error of glycogen metabolism due to mutations in SLC37A4. Besides a severe form of fasting intolerance, the disorder is usually associated with neutropenia and neutrophil dysfunction causing serious infections, inflammatory bowel disease, oral, urogenital and perianal lesions as well as impaired wound healing. Recently, SGLT2 inhibitors such as empagliflozin that reduce the plasma levels of 1,5-anhydroglucitol have been described as a new treatment option for the neutropenia and neutrophil dysfunction in patients with GSD Ib. Results We report on a 35-year-old female patient with GSD Ib who had been treated with G-CSF for neutropenia since the age of 9. She had a large chronic abdominal wound as a consequence of recurrent operations due to complications of her inflammatory bowel disease. Treatment with 20 mg empagliflozin per day resulted in normalisation of the neutrophil count and neutrophil function even after termination of G-CSF. The chronic abdominal wound that had been unchanged for 2 years before the start of empagliflozin nearly closed within 12 weeks. No side effects of empagliflozin were observed. Conclusion SGLT2 inhibitors are a new and probably safe treatment option for GSD Ib-associated neutropenia and neutrophil dysfunction. We hypothesize that restoration of neutrophil function and normalisation of neutrophil apoptosis leads to improvement of wound healing and ameliorates symptoms of inflammatory bowel disease.
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Affiliation(s)
- Sarah C Grünert
- Department of General Paediatrics, Adolescent Medicine and Neonatology, Medical Centre- University of Freiburg, Faculty of Medicine, Mathildenstraße 1, 79106, Freiburg, Germany.
| | - Roland Elling
- Department of General Paediatrics, Adolescent Medicine and Neonatology, Medical Centre- University of Freiburg, Faculty of Medicine, Mathildenstraße 1, 79106, Freiburg, Germany
| | - Bärbel Maag
- Department of General Paediatrics, Adolescent Medicine and Neonatology, Medical Centre- University of Freiburg, Faculty of Medicine, Mathildenstraße 1, 79106, Freiburg, Germany
| | - Saskia B Wortmann
- University Children's Hospital, Paracelsus Medical University (PMU), Salzburg, Austria.,Radboud Center for Mitochondrial Medicine, Department of Pediatrics, Amalia Children's Hospital, Radboudumc, Nijmegen, The Netherlands
| | - Terry G J Derks
- Section of Metabolic Diseases, Beatrix Children's Hospital, University Medical Centre Groningen, University of Groningen, Groningen, The Netherlands
| | - Luciana Hannibal
- Department of General Paediatrics, Adolescent Medicine and Neonatology, Laboratory of Clinical Biochemistry and Metabolism, Medical Centre-University of Freiburg, Faculty of Medicine, Freiburg, Germany
| | - Anke Schumann
- Department of General Paediatrics, Adolescent Medicine and Neonatology, Medical Centre- University of Freiburg, Faculty of Medicine, Mathildenstraße 1, 79106, Freiburg, Germany
| | - Stefanie Rosenbaum-Fabian
- Department of General Paediatrics, Adolescent Medicine and Neonatology, Medical Centre- University of Freiburg, Faculty of Medicine, Mathildenstraße 1, 79106, Freiburg, Germany
| | - Ute Spiekerkoetter
- Department of General Paediatrics, Adolescent Medicine and Neonatology, Medical Centre- University of Freiburg, Faculty of Medicine, Mathildenstraße 1, 79106, Freiburg, Germany
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10
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Bosma KJ, Rahim M, Singh K, Goleva SB, Wall ML, Xia J, Syring KE, Oeser JK, Poffenberger G, McGuinness OP, Means AL, Powers AC, Li WH, Davis LK, Young JD, O’Brien RM. Pancreatic islet beta cell-specific deletion of G6pc2 reduces fasting blood glucose. J Mol Endocrinol 2020; 64:235-248. [PMID: 32213654 PMCID: PMC7331801 DOI: 10.1530/jme-20-0031] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/13/2020] [Indexed: 12/25/2022]
Abstract
The G6PC1, G6PC2 and G6PC3 genes encode distinct glucose-6-phosphatase catalytic subunit (G6PC) isoforms. In mice, germline deletion of G6pc2 lowers fasting blood glucose (FBG) without affecting fasting plasma insulin (FPI) while, in isolated islets, glucose-6-phosphatase activity and glucose cycling are abolished and glucose-stimulated insulin secretion (GSIS) is enhanced at submaximal but not high glucose. These observations are all consistent with a model in which G6PC2 regulates the sensitivity of GSIS to glucose by opposing the action of glucokinase. G6PC2 is highly expressed in human and mouse islet beta cells however, various studies have shown trace G6PC2 expression in multiple tissues raising the possibility that G6PC2 also affects FBG through non-islet cell actions. Using real-time PCR we show here that expression of G6pc1 and/or G6pc3 are much greater than G6pc2 in peripheral tissues, whereas G6pc2 expression is much higher than G6pc3 in both pancreas and islets with G6pc1 expression not detected. In adult mice, beta cell-specific deletion of G6pc2 was sufficient to reduce FBG without changing FPI. In addition, electronic health record-derived phenotype analyses showed no association between G6PC2 expression and phenotypes clearly unrelated to islet function in humans. Finally, we show that germline G6pc2 deletion enhances glycolysis in mouse islets and that glucose cycling can also be detected in human islets. These observations are all consistent with a mechanism by which G6PC2 action in islets is sufficient to regulate the sensitivity of GSIS to glucose and hence influence FBG without affecting FPI.
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Affiliation(s)
- Karin J. Bosma
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Mohsin Rahim
- Department of Chemical and Biomolecular Engineering, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Kritika Singh
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Slavina B. Goleva
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Martha L. Wall
- Department of Chemical and Biomolecular Engineering, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Jing Xia
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
| | - Kristen E. Syring
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - James K. Oeser
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Greg Poffenberger
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Owen P. McGuinness
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Anna L. Means
- Department of Surgery, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Alvin C. Powers
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
- VA Tennessee Valley Healthcare System, Nashville, TN 37232
| | - Wen-hong Li
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
| | - Lea K. Davis
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Jamey D. Young
- Department of Chemical and Biomolecular Engineering, Vanderbilt University School of Medicine, Nashville, TN 37232
| | - Richard M. O’Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232
- To whom correspondence should be addressed: Department of Molecular Physiology and Biophysics, 8415 MRB IV, 2213 Garland Ave, Vanderbilt University Medical School, Nashville, TN 37232-0615,
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11
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Pascoal C, Francisco R, Ferro T, Dos Reis Ferreira V, Jaeken J, Videira PA. CDG and immune response: From bedside to bench and back. J Inherit Metab Dis 2020; 43:90-124. [PMID: 31095764 DOI: 10.1002/jimd.12126] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/13/2019] [Accepted: 05/15/2019] [Indexed: 12/20/2022]
Abstract
Glycosylation is an essential biological process that adds structural and functional diversity to cells and molecules, participating in physiological processes such as immunity. The immune response is driven and modulated by protein-attached glycans that mediate cell-cell interactions, pathogen recognition and cell activation. Therefore, abnormal glycosylation can be associated with deranged immune responses. Within human diseases presenting immunological defects are congenital disorders of glycosylation (CDG), a family of around 130 rare and complex genetic diseases. In this review, we have identified 23 CDG with immunological involvement, characterized by an increased propensity to-often life-threatening-infection. Inflammatory and autoimmune complications were found in 7 CDG types. CDG natural history(ies) and the mechanisms behind the immunological anomalies are still poorly understood. However, in some cases, alterations in pathogen recognition and intracellular signaling (eg, TGF-β1, NFAT, and NF-κB) have been suggested. Targeted therapies to restore immune defects are only available for PGM3-CDG and SLC35C1-CDG. Fostering research on glycoimmunology may elucidate the involved pathophysiological mechanisms and open new therapeutic avenues, thus improving CDG patients' quality of life.
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Affiliation(s)
- Carlota Pascoal
- Portuguese Association for CDG, Lisbon, Portugal
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Rita Francisco
- Portuguese Association for CDG, Lisbon, Portugal
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Tiago Ferro
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Vanessa Dos Reis Ferreira
- Portuguese Association for CDG, Lisbon, Portugal
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
| | - Jaak Jaeken
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- Center for Metabolic Diseases, Department of Development and Regeneration, UZ and KU Leuven, Leuven, Belgium
| | - Paula A Videira
- Portuguese Association for CDG, Lisbon, Portugal
- CDG & Allies - Professionals and Patient Associations International Network (CDG & Allies - PPAIN), Caparica, Portugal
- UCIBIO, Departamento Ciências da Vida, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Caparica, Portugal
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12
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Veiga‐da‐Cunha M, Van Schaftingen E, Bommer GT. Inborn errors of metabolite repair. J Inherit Metab Dis 2020; 43:14-24. [PMID: 31691304 PMCID: PMC7041631 DOI: 10.1002/jimd.12187] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Revised: 10/18/2019] [Accepted: 11/04/2019] [Indexed: 12/11/2022]
Abstract
It is traditionally assumed that enzymes of intermediary metabolism are extremely specific and that this is sufficient to prevent the production of useless and/or toxic side-products. Recent work indicates that this statement is not entirely correct. In reality, enzymes are not strictly specific, they often display weak side activities on intracellular metabolites (substrate promiscuity) that resemble their physiological substrate or slowly catalyse abnormal reactions on their physiological substrate (catalytic promiscuity). They thereby produce non-classical metabolites that are not efficiently metabolised by conventional enzymes. In an increasing number of cases, metabolite repair enzymes are being discovered that serve to eliminate these non-classical metabolites and prevent their accumulation. Metabolite repair enzymes also eliminate non-classical metabolites that are formed through spontaneous (ie, not enzyme-catalysed) reactions. Importantly, genetic deficiencies in several metabolite repair enzymes lead to 'inborn errors of metabolite repair', such as L-2-hydroxyglutaric aciduria, D-2-hydroxyglutaric aciduria, 'ubiquitous glucose-6-phosphatase' (G6PC3) deficiency, the neutropenia present in Glycogen Storage Disease type Ib or defects in the enzymes that repair the hydrated forms of NADH or NADPH. Metabolite repair defects may be difficult to identify as such, because the mutated enzymes are non-classical enzymes that act on non-classical metabolites, which in some cases accumulate only inside the cells, and at rather low, yet toxic, concentrations. It is therefore likely that many additional metabolite repair enzymes remain to be discovered and that many diseases of metabolite repair still await elucidation.
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Affiliation(s)
| | - Emile Van Schaftingen
- de Duve InstituteUniversité Catholique de Louvain (UCLouvain)BrusselsBelgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO)UCLouvainBrusselsBelgium
| | - Guido T. Bommer
- de Duve InstituteUniversité Catholique de Louvain (UCLouvain)BrusselsBelgium
- Walloon Excellence in Life Sciences and Biotechnology (WELBIO)UCLouvainBrusselsBelgium
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13
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Sim SW, Weinstein DA, Lee YM, Jun HS. Glycogen storage disease type Ib: role of glucose‐6‐phosphate transporter in cell metabolism and function. FEBS Lett 2019; 594:3-18. [DOI: 10.1002/1873-3468.13666] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 10/16/2019] [Accepted: 10/25/2019] [Indexed: 12/19/2022]
Affiliation(s)
- Sang Wan Sim
- Department of Biotechnology and Bioinformatics College of Science and Technology Korea University Sejong Korea
| | - David A. Weinstein
- Glycogen Storage Disease Program University of Connecticut School of Medicine Farmington CT USA
| | - Young Mok Lee
- Glycogen Storage Disease Program University of Connecticut School of Medicine Farmington CT USA
| | - Hyun Sik Jun
- Department of Biotechnology and Bioinformatics College of Science and Technology Korea University Sejong Korea
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14
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Failure to eliminate a phosphorylated glucose analog leads to neutropenia in patients with G6PT and G6PC3 deficiency. Proc Natl Acad Sci U S A 2019; 116:1241-1250. [PMID: 30626647 PMCID: PMC6347702 DOI: 10.1073/pnas.1816143116] [Citation(s) in RCA: 90] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Neutropenia presents an important clinical problem in patients with G6PC3 or G6PT deficiency, yet why neutropenia occurs is unclear. We discovered that G6PC3 and G6PT collaborate to dephosphorylate a noncanonical metabolite (1,5-anhydroglucitol-6-phosphate; 1,5AG6P) which is produced when glucose-phosphorylating enzymes erroneously act on 1,5-anhydroglucitol, a food-derived polyol present in blood. In patients or mice with G6PC3 or G6PT deficiency, 1,5AG6P accumulates and inhibits the first step of glycolysis. This is particularly detrimental in neutrophils, since their energy metabolism depends almost entirely on glycolysis. Consistent with our findings, we observed that treatment with a 1,5-anhydroglucitol-lowering drug treats neutropenia in G6PC3-deficient mice. Our findings highlight that the elimination of noncanonical side products by metabolite-repair enzymes makes an important contribution to mammalian physiology. Neutropenia represents an important problem in patients with genetic deficiency in either the glucose-6-phosphate transporter of the endoplasmic reticulum (G6PT/SLC37A4) or G6PC3, an endoplasmic reticulum phosphatase homologous to glucose-6-phosphatase. While affected granulocytes show reduced glucose utilization, the underlying mechanism is unknown and causal therapies are lacking. Using a combination of enzymological, cell-culture, and in vivo approaches, we demonstrate that G6PT and G6PC3 collaborate to destroy 1,5-anhydroglucitol-6-phosphate (1,5AG6P), a close structural analog of glucose-6-phosphate and an inhibitor of low-KM hexokinases, which catalyze the first step in glycolysis in most tissues. We show that 1,5AG6P is made by phosphorylation of 1,5-anhydroglucitol, a compound normally present in human plasma, by side activities of ADP-glucokinase and low-KM hexokinases. Granulocytes from patients deficient in G6PC3 or G6PT accumulate 1,5AG6P to concentrations (∼3 mM) that strongly inhibit hexokinase activity. In a model of G6PC3-deficient mouse neutrophils, physiological concentrations of 1,5-anhydroglucitol caused massive accumulation of 1,5AG6P, a decrease in glucose utilization, and cell death. Treating G6PC3-deficient mice with an inhibitor of the kidney glucose transporter SGLT2 to lower their blood level of 1,5-anhydroglucitol restored a normal neutrophil count, while administration of 1,5-anhydroglucitol had the opposite effect. In conclusion, we show that the neutropenia in patients with G6PC3 or G6PT mutations is a metabolite-repair deficiency, caused by a failure to eliminate the nonclassical metabolite 1,5AG6P.
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15
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Ponzi E, Maiorana A, Lepri FR, Mucciolo M, Semeraro M, Taurisano R, Olivieri G, Novelli A, Dionisi-Vici C. Persistent Hypoglycemia in Children: Targeted Gene Panel Improves the Diagnosis of Hypoglycemia Due to Inborn Errors of Metabolism. J Pediatr 2018; 202:272-278.e4. [PMID: 30193751 DOI: 10.1016/j.jpeds.2018.06.050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/26/2018] [Accepted: 06/14/2018] [Indexed: 12/11/2022]
Abstract
OBJECTIVES To evaluate the role of next generation sequencing in genetic diagnosis of pediatric patients with persistent hypoglycemia. STUDY DESIGN Sixty-four patients investigated through an extensive workup were divided in 3 diagnostic classes based on the likelihood of a genetic diagnosis: (1) single candidate gene (9/64); (2) multiple candidate genes (43/64); and (3) no candidate gene (12/64). Subsequently, patients were tested through a custom gene panel of 65 targeted genes, which included 5 disease categories: (1) hyperinsulinemic hypoglycemia, (2) fatty acid-oxidation defects and ketogenesis defects, (3) ketolysis defects, (4) glycogen storage diseases and other disorders of carbohydrate metabolism, and (5) mitochondrial disorders. Molecular data were compared with clinical and biochemical data. RESULTS A proven diagnosis was obtained in 78% of patients with suspicion for a single candidate gene, in 49% with multiple candidate genes, and in 33% with no candidate gene. The diagnostic yield was 48% for hyperinsulinemic hypoglycemia, 66% per fatty acid-oxidation and ketogenesis defects, 59% for glycogen storage diseases and other carbohydrate disorders, and 67% for mitochondrial disorders. CONCLUSIONS This approach provided a diagnosis in ~50% of patients in whom clinical and laboratory evaluation did not allow identification of a single candidate gene and a diagnosis was established in 33% of patients belonging to the no candidate gene class. Next generation sequencing technique is cost-effective compared with Sanger sequencing of multiple genes and represents a powerful tool for the diagnosis of inborn errors of metabolism presenting with persistent hypoglycemia.
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Affiliation(s)
- Emanuela Ponzi
- Division of Metabolic Diseases, Department of Pediatric Specialties, Bambino Gesù Children's Hospital, Rome, Italy
| | - Arianna Maiorana
- Division of Metabolic Diseases, Department of Pediatric Specialties, Bambino Gesù Children's Hospital, Rome, Italy
| | - Francesca Romana Lepri
- Medical Genetics Unit, Medical Genetics Laboratory, Bambino Gesù Children's Hospital, Rome, Italy
| | - Mafalda Mucciolo
- Medical Genetics Unit, Medical Genetics Laboratory, Bambino Gesù Children's Hospital, Rome, Italy
| | - Michela Semeraro
- Division of Metabolic Diseases, Department of Pediatric Specialties, Bambino Gesù Children's Hospital, Rome, Italy
| | - Roberta Taurisano
- Division of Metabolic Diseases, Department of Pediatric Specialties, Bambino Gesù Children's Hospital, Rome, Italy
| | - Giorgia Olivieri
- Division of Metabolic Diseases, Department of Pediatric Specialties, Bambino Gesù Children's Hospital, Rome, Italy; Unit of Child Neurology, Catholic University, Fondazione Policlinico A. Gemelli, Rome, Italy
| | - Antonio Novelli
- Medical Genetics Unit, Medical Genetics Laboratory, Bambino Gesù Children's Hospital, Rome, Italy
| | - Carlo Dionisi-Vici
- Division of Metabolic Diseases, Department of Pediatric Specialties, Bambino Gesù Children's Hospital, Rome, Italy.
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16
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Depaoli MR, Hay JC, Graier WF, Malli R. The enigmatic ATP supply of the endoplasmic reticulum. Biol Rev Camb Philos Soc 2018; 94:610-628. [PMID: 30338910 PMCID: PMC6446729 DOI: 10.1111/brv.12469] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 08/20/2018] [Accepted: 08/30/2018] [Indexed: 12/11/2022]
Abstract
The endoplasmic reticulum (ER) is a functionally and morphologically complex cellular organelle largely responsible for a variety of crucial functions, including protein folding, maturation and degradation. Furthermore, the ER plays an essential role in lipid biosynthesis, dynamic Ca2+ storage, and detoxification. Malfunctions in ER‐related processes are responsible for the genesis and progression of many diseases, such as heart failure, cancer, neurodegeneration and metabolic disorders. To fulfill many of its vital functions, the ER relies on a sufficient energy supply in the form of adenosine‐5′‐triphosphate (ATP), the main cellular energy source. Despite landmark discoveries and clarification of the functional principles of ER‐resident proteins and key ER‐related processes, the mechanism underlying ER ATP transport remains somewhat enigmatic. Here we summarize ER‐related ATP‐consuming processes and outline our knowledge about the nature and function of the ER energy supply.
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Affiliation(s)
- Maria R Depaoli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria
| | - Jesse C Hay
- Division of Biological Sciences and Center for Structural and Functional Neuroscience, The University of Montana, 32 Campus Drive, HS410, Missoula, MT 59812-4824, U.S.A
| | - Wolfgang F Graier
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria.,BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
| | - Roland Malli
- Molecular Biology and Biochemistry, Gottfried Schatz Research Center, Medical University of Graz, Neue Stiftingtalstraße 6/6, 8010 Graz, Austria.,BioTechMed Graz, Mozartgasse 12/II, 8010 Graz, Austria
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17
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Park D, Goh CJ, Kim H, Lee JS, Hahn Y. Loss of conserved ubiquitylation sites in conserved proteins during human evolution. Int J Mol Med 2018; 42:2203-2212. [PMID: 30015863 DOI: 10.3892/ijmm.2018.3772] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 07/06/2018] [Indexed: 11/06/2022] Open
Abstract
Ubiquitylation of lysine residues in proteins serves a pivotal role in the efficient removal of misfolded or unused proteins and in the control of various regulatory pathways by monitoring protein activity that may lead to protein degradation. The loss of ubiquitylated lysines may affect the ubiquitin‑mediated regulatory network and result in the emergence of novel phenotypes. The present study analyzed mouse ubiquitylation data and orthologous proteins from 62 mammals to identify 193 conserved ubiquitylation sites from 169 proteins that were lost in the Euarchonta lineage leading to humans. A total of 8 proteins, including betaine homocysteine S‑methyltransferase, clin and CBS domain divalent metal cation transport mediator 3, ribosome‑binding protein 1 and solute carrier family 37 member 4, lost 1 conserved lysine residue, which was ubiquitylated in the mouse ortholog, following the human‑chimpanzee divergence. A total of 17 of the lost ubiquitylated lysines are also known to be modified by acetylation and/or succinylation in mice. In 8 cases, a novel lysine evolved at positions flanking the lost conserved lysine residues, potentially as a method of compensation. We hypothesize that the loss of ubiquitylation sites during evolution may lead to the development of advantageous phenotypes, which are then fixed by selection. The ancestral ubiquitylation sites identified in the present study may be a useful resource for investigating the association between loss of ubiquitylation sites and the emergence of novel phenotypes during evolution towards modern humans.
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Affiliation(s)
- Dongbin Park
- Department of Life Science, Chung‑Ang University, Seoul 06974, Republic of Korea
| | - Chul Jun Goh
- Department of Life Science, Chung‑Ang University, Seoul 06974, Republic of Korea
| | - Hyein Kim
- Department of Life Science, Chung‑Ang University, Seoul 06974, Republic of Korea
| | - Ji Seok Lee
- Department of Life Science, Chung‑Ang University, Seoul 06974, Republic of Korea
| | - Yoonsoo Hahn
- Department of Life Science, Chung‑Ang University, Seoul 06974, Republic of Korea
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Cappello AR, Curcio R, Lappano R, Maggiolini M, Dolce V. The Physiopathological Role of the Exchangers Belonging to the SLC37 Family. Front Chem 2018; 6:122. [PMID: 29719821 PMCID: PMC5913288 DOI: 10.3389/fchem.2018.00122] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2018] [Accepted: 03/30/2018] [Indexed: 12/14/2022] Open
Abstract
The human SLC37 gene family includes four proteins SLC37A1-4, localized in the endoplasmic reticulum (ER) membrane. They have been grouped into the SLC37 family due to their sequence homology to the bacterial organophosphate/phosphate (Pi) antiporter. SLC37A1-3 are the less characterized isoforms. SLC37A1 and SLC37A2 are Pi-linked glucose-6-phosphate (G6P) antiporters, catalyzing both homologous (Pi/Pi) and heterologous (G6P/Pi) exchanges, whereas SLC37A3 transport properties remain to be clarified. Furthermore, SLC37A1 is highly homologous to the bacterial glycerol 3-phosphate permeases, so it is supposed to transport also glycerol-3-phosphate. The physiological role of SLC37A1-3 is yet to be further investigated. SLC37A1 seems to be required for lipid biosynthesis in cancer cell lines, SLC37A2 has been proposed as a vitamin D and a phospho-progesterone receptor target gene, while mutations in the SLC37A3 gene appear to be associated with congenital hyperinsulinism of infancy. SLC37A4, also known as glucose-6-phosphate translocase (G6PT), transports G6P from the cytoplasm into the ER lumen, working in complex with either glucose-6-phosphatase-α (G6Pase-α) or G6Pase-β to hydrolyze intraluminal G6P to Pi and glucose. G6PT and G6Pase-β are ubiquitously expressed, whereas G6Pase-α is specifically expressed in the liver, kidney and intestine. G6PT/G6Pase-α complex activity regulates fasting blood glucose levels, whereas G6PT/G6Pase-β is required for neutrophil functions. G6PT deficiency is responsible for glycogen storage disease type Ib (GSD-Ib), an autosomal recessive disorder associated with both defective metabolic and myeloid phenotypes. Several kinds of mutations have been identified in the SLC37A4 gene, affecting G6PT function. An increased autoimmunity risk for GSD-Ib patients has also been reported, moreover, SLC37A4 seems to be involved in autophagy.
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Affiliation(s)
- Anna Rita Cappello
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Rosita Curcio
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Rosamaria Lappano
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Marcello Maggiolini
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
| | - Vincenza Dolce
- Department of Pharmacy, Health and Nutritional Sciences, University of Calabria, Rende, Italy
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Matched unrelated donor transplantation in glycogen storage disease type 1b patient corrects severe neutropenia and recurrent infections. Bone Marrow Transplant 2018. [DOI: 10.1038/s41409-018-0147-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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Abstract
Neutrophils are the primary cells recruited to inflamed sites during an innate immune response to tissue damage and/or infection. They are finely sensitive to inciting stimuli to reach in great numbers and within minutes areas of inflammation and tissue insult. For this effective response, they can detect extracellular chemical gradients and move towards higher concentrations, the so-called chemotaxis process or guided cell migration. This directed neutrophil recruitment is orchestrated by chemoattractants, a chemically diverse group of molecular guidance cues (e.g., lipids, N-formylated peptides, complement, anaphylotoxins and chemokines). Neutrophils respond to these guidance signals in a hierarchical manner and, based on this concept, they can be further subdivided into two groups: "end target" and "intermediary" chemoattractants, the signals of the former dominant over the latter. Neutrophil chemoattractants exert their effects through interaction with heptahelical G protein-coupled receptors (GPCRs) expressed on cell surfaces and the chemotactic response is mainly regulated by the Rho family of GTPases. Additionally, neutrophil behavior might differ and be affected in different complex scenarios such as disease conditions and type of vascular bed in specific organs. Finally, there are different mechanisms to disrupt neutrophil chemotaxis either associated to the resolution of inflammation or to bacterial escape and systemic infection. Therefore, in the present review, we will discuss the different molecular players involved in neutrophil chemotaxis, paying special attention to the different chemoattractants described and the way that they interact intra- and extravascularly for neutrophils to properly reach the target tissue.
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Affiliation(s)
- Björn Petri
- Snyder Institute for Chronic Diseases Mouse Phenomics Resource Laboratory, University of Calgary, Calgary, AB, T2N 4N1, Canada. .,Department of Microbiology, Immunology and Infectious Diseases, Cumming School of Medicine, University of Calgary, Calgary, AB, T2N 4N1, Canada.
| | - Maria-Jesús Sanz
- Institute of Health Research INCLIVA, University Clinic Hospital of Valencia, Valencia, Spain. .,Departamento de Farmacología, Facultad de Medicina, Universidad de Valencia, Valencia, Spain.
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Letkemann R, Wittkowski H, Antonopoulos A, Podskabi T, Haslam SM, Föll D, Dell A, Marquardt T. Partial correction of neutrophil dysfunction by oral galactose therapy in glycogen storage disease type Ib. Int Immunopharmacol 2017; 44:216-225. [PMID: 28126686 DOI: 10.1016/j.intimp.2017.01.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Revised: 01/06/2017] [Accepted: 01/10/2017] [Indexed: 01/30/2023]
Abstract
Glycogen storage disease type Ib (GSD-Ib) is characterized by impaired glucose homeostasis, neutropenia and neutrophil dysfunction. Mass spectrometric glycomic profiling of GSD-Ib neutrophils showed severely truncated N-glycans, lacking galactose. Experiments indicated the hypoglycosylation of the electron transporting subunit of NADPH oxidase, which is crucial for the defense against bacterial infections. In phosphoglucomutase 1 (PGM1) deficiency, an inherited disorder with an enzymatic defect just one metabolic step ahead, hypogalactosylation can be successfully treated by dietary galactose. We hypothesized the same pathomechanism in GSD-Ib and started a therapeutic trial with oral galactose and uridine. The aim was to improve neutrophil dysfunction through the correction of hypoglycosylation in neutrophils. The GSD-Ib patient was treated for 29weeks. Monitoring included glycomics analysis of the patient's neutrophils and neutrophil function tests including respiratory burst activity, phagocytosis and migration. Although no substantial restoration of neutrophil glycosylation was found, there was partial improvement of respiratory burst activity.
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Affiliation(s)
- Rudolf Letkemann
- Department of General Pediatrics, Metabolic Diseases, University Children's Hospital Muenster, Germany.
| | - Helmut Wittkowski
- Department of Pediatric Rheumatology and Imunology, University Children's Hospital Muenster, Germany.
| | | | - Teodor Podskabi
- Molecular Genetics and Metabolism Laboratory, Munich, Germany.
| | - Stuart M Haslam
- Department of Life Sciences, Imperial College London, SW7 2AZ, UK.
| | - Dirk Föll
- Department of Pediatric Rheumatology and Imunology, University Children's Hospital Muenster, Germany.
| | - Anne Dell
- Department of Life Sciences, Imperial College London, SW7 2AZ, UK.
| | - Thorsten Marquardt
- Department of General Pediatrics, Metabolic Diseases, University Children's Hospital Muenster, Germany.
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22
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Chen MA, Weinstein DA. Glycogen storage diseases: Diagnosis, treatment and outcome. ACTA ACUST UNITED AC 2016. [DOI: 10.3233/trd-160006] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
| | - David A. Weinstein
- Glycogen Storage Disease Program, University of Florida College of Medicine, Gainesville, FL, USA
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23
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Hytönen MK, Arumilli M, Lappalainen AK, Owczarek-Lipska M, Jagannathan V, Hundi S, Salmela E, Venta P, Sarkiala E, Jokinen T, Gorgas D, Kere J, Nieminen P, Drögemüller C, Lohi H. Molecular Characterization of Three Canine Models of Human Rare Bone Diseases: Caffey, van den Ende-Gupta, and Raine Syndromes. PLoS Genet 2016; 12:e1006037. [PMID: 27187611 PMCID: PMC4871343 DOI: 10.1371/journal.pgen.1006037] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 04/18/2016] [Indexed: 12/03/2022] Open
Abstract
One to two percent of all children are born with a developmental disorder requiring pediatric hospital admissions. For many such syndromes, the molecular pathogenesis remains poorly characterized. Parallel developmental disorders in other species could provide complementary models for human rare diseases by uncovering new candidate genes, improving the understanding of the molecular mechanisms and opening possibilities for therapeutic trials. We performed various experiments, e.g. combined genome-wide association and next generation sequencing, to investigate the clinico-pathological features and genetic causes of three developmental syndromes in dogs, including craniomandibular osteopathy (CMO), a previously undescribed skeletal syndrome, and dental hypomineralization, for which we identified pathogenic variants in the canine SLC37A2 (truncating splicing enhancer variant), SCARF2 (truncating 2-bp deletion) and FAM20C (missense variant) genes, respectively. CMO is a clinical equivalent to an infantile cortical hyperostosis (Caffey disease), for which SLC37A2 is a new candidate gene. SLC37A2 is a poorly characterized member of a glucose-phosphate transporter family without previous disease associations. It is expressed in many tissues, including cells of the macrophage lineage, e.g. osteoclasts, and suggests a disease mechanism, in which an impaired glucose homeostasis in osteoclasts compromises their function in the developing bone, leading to hyperostosis. Mutations in SCARF2 and FAM20C have been associated with the human van den Ende-Gupta and Raine syndromes that include numerous features similar to the affected dogs. Given the growing interest in the molecular characterization and treatment of human rare diseases, our study presents three novel physiologically relevant models for further research and therapy approaches, while providing the molecular identity for the canine conditions. Rare developmental disorders make a major contribution to pediatric hospital admissions and mortality. There is a growing interest in the development of therapeutics for these conditions, but that requires understanding of the genetic cause and pathology. Research can be facilitated by physiologically relevant models, such as dogs with corresponding disorders. We have characterized the clinical features and genetic causes of three developmental syndromes in dogs, including craniomandibular osteopathy (CMO), a previously undescribed skeletal syndrome, and dental hypomineralization, for which we identified mutations in the canine SLC37A2, SCARF2 and FAM20C genes, respectively. CMO is a clinical equivalent to an infantile cortical hyperostosis (Caffey disease) for which SLC37A2 is a new candidate gene. SLC37A2 is a glucose-phosphate transporter in osteoclasts, and its defect suggests an impaired glucose homeostasis in developing bone, leading to hyperostosis. Mutations in the SCARF2 and FAM20C genes have been associated with the human van den Ende-Gupta and Raine syndromes. Our study provides molecular identity for the canine conditions and presents three novel physiologically relevant models of human rare diseases.
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Affiliation(s)
- Marjo K. Hytönen
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Meharji Arumilli
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Anu K. Lappalainen
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | | | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Sruthi Hundi
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Elina Salmela
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
| | - Patrick Venta
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, United States of America
| | - Eva Sarkiala
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - Tarja Jokinen
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
- Department of Equine and Small Animal Medicine, University of Helsinki, Helsinki, Finland
| | - Daniela Gorgas
- Division of Clinical Radiology, Department of Clinical Veterinary Medicine, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Juha Kere
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Pekka Nieminen
- Department of Oral and Maxillofacial Diseases, University of Helsinki, Helsinki, Finland
| | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, Bern, Switzerland
| | - Hannes Lohi
- Department of Veterinary Biosciences, University of Helsinki, Helsinki, Finland
- Research Programs Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland
- The Folkhälsan Institute of Genetics, Helsinki, Finland
- * E-mail:
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Chou JY, Jun HS, Mansfield BC. Type I glycogen storage diseases: disorders of the glucose-6-phosphatase/glucose-6-phosphate transporter complexes. J Inherit Metab Dis 2015; 38:511-9. [PMID: 25288127 DOI: 10.1007/s10545-014-9772-x] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Revised: 08/12/2014] [Accepted: 09/12/2014] [Indexed: 12/15/2022]
Abstract
Disorders of the glucose-6-phosphatase (G6Pase)/glucose-6-phosphate transporter (G6PT) complexes consist of three subtypes: glycogen storage disease type Ia (GSD-Ia), deficient in the liver/kidney/intestine-restricted G6Pase-α (or G6PC); GSD-Ib, deficient in a ubiquitously expressed G6PT (or SLC37A4); and G6Pase-β deficiency or severe congenital neutropenia syndrome type 4 (SCN4), deficient in the ubiquitously expressed G6Pase-β (or G6PC3). G6Pase-α and G6Pase-β are glucose-6-phosphate (G6P) hydrolases with active sites lying inside the endoplasmic reticulum (ER) lumen and as such are dependent upon the G6PT to translocate G6P from the cytoplasm into the lumen. The tissue expression profiles of the G6Pase enzymes dictate the disease's phenotype. A functional G6Pase-α/G6PT complex maintains interprandial glucose homeostasis, while a functional G6Pase-β/G6PT complex maintains neutrophil/macrophage energy homeostasis and functionality. G6Pase-β deficiency is not a glycogen storage disease but biochemically it is a GSD-I related syndrome (GSD-Irs). GSD-Ia and GSD-Ib patients manifest a common metabolic phenotype of impaired blood glucose homeostasis not shared by GSD-Irs. GSD-Ib and GSD-Irs patients manifest a common myeloid phenotype of neutropenia and neutrophil/macrophage dysfunction not shared by GSD-Ia. While a disruption of the activity of the G6Pase-α/G6PT complex readily explains why GSD-Ia and GSD-Ib patients exhibit impaired glucose homeostasis, the basis for neutropenia and myeloid dysfunction in GSD-Ib and GSD-Irs are only now starting to be understood. Animal models of all three disorders are now available and are being exploited to both delineate the disease more precisely and develop new treatment approaches, including gene therapy.
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Affiliation(s)
- Janice Y Chou
- Section on Cellular Differentiation, Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, 20892, USA,
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25
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Abstract
Neutrophil granulocytes are key effector cells of the vertebrate immune system. They represent 50-70% of the leukocytes in the human blood and their loss by disease or drug side effect causes devastating bacterial infections. Their high turnover rate, their fine-tuned killing machinery, and their arsenal of toxic vesicles leave them particularly vulnerable to various genetic deficiencies. The aim of this review is to highlight those congenital immunodeficiencies which impede the dynamics of neutrophils, such as migration, cytoskeletal rearrangements, vesicular trafficking, and secretion.
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26
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Affiliation(s)
- Philippe Labrune
- Service de Pédiatrie et Consultation de Génétique, Hôpital Antoine Béclère (AP-HP), BP 405, 92141 Clamart cedex, France.
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27
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Oosterveer MH, Schoonjans K. Hepatic glucose sensing and integrative pathways in the liver. Cell Mol Life Sci 2014; 71:1453-67. [PMID: 24196749 PMCID: PMC11114046 DOI: 10.1007/s00018-013-1505-z] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 10/17/2013] [Accepted: 10/18/2013] [Indexed: 12/21/2022]
Abstract
The hepatic glucose-sensing system is a functional network of enzymes and transcription factors that is critical for the maintenance of energy homeostasis and systemic glycemia. Here we review the recent literature on its components and metabolic actions. Glucokinase (GCK) is generally considered as the initial postprandial glucose-sensing component, which acts as the gatekeeper for hepatic glucose metabolism and provides metabolites that activate the transcription factor carbohydrate response element binding protein (ChREBP). Recently, liver receptor homolog 1 (LRH-1) has emerged as an upstream regulator of the central GCK-ChREBP axis, with a critical role in the integration of hepatic intermediary metabolism in response to glucose. Evidence is also accumulating that O-linked β-N-acetylglucosaminylation (O-GlcNAcylation) and acetylation can act as glucose-sensitive modifications that may contribute to hepatic glucose sensing by targeting regulatory proteins and the epigenome. Further elucidation of the components and functional roles of the hepatic glucose-sensing system may contribute to the future treatment of liver diseases associated with deregulated glucose sensors.
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Affiliation(s)
- Maaike H. Oosterveer
- Department of Pediatrics and Laboratory Medicine, University of Groningen, University Medical Center Groningen, 9713 GZ Groningen, The Netherlands
| | - Kristina Schoonjans
- Institute of Bioengineering, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
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28
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Wlcek K, Hofstetter L, Stieger B. Transport of estradiol-17β-glucuronide, estrone-3-sulfate and taurocholate across the endoplasmic reticulum membrane: evidence for different transport systems. Biochem Pharmacol 2014; 88:106-18. [PMID: 24406246 PMCID: PMC3969151 DOI: 10.1016/j.bcp.2013.12.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2013] [Revised: 12/23/2013] [Accepted: 12/23/2013] [Indexed: 11/06/2022]
Abstract
Important reactions of drug metabolism, including UGT mediated glucuronidation and steroidsulfatase mediated hydrolysis of sulfates, take place in the endoplasmic reticulum (ER) of hepatocytes. Consequently, UGT generated glucuronides, like estradiol-17β-glucuronide, have to be translocated back into the cytoplasm to reach their site of excretion. Also steroidsulfatase substrates, including estrone-3-sulfate, have to cross the ER membrane to reach their site of hydrolysis. Based on their physicochemical properties such compounds are not favored for passive diffusion and therefore likely necessitate transport system(s) to cross the ER membrane in either direction. The current study aims to investigate the transport of taurocholate, estradiol-17β-glucuronide, and estrone-3-sulfate in smooth (SER) and rough (RER) endoplasmic reticulum membrane vesicles isolated from Wistar and TR− rat liver. Time-dependent and bidirectional transport was demonstrated for taurocholate, showing higher uptake rates in SER than RER vesicles. For estradiol-17β-glucuronide a fast time-dependent efflux with similar efficiencies from SER and RER but no clear protein-mediated uptake was shown, indicating an asymmetric transport system for this substrate. Estrone-3-sulfate uptake was time-dependent and higher in SER than in RER vesicles. Inhibition of steroidsulfatase mediated estrone-3-sulfate hydrolysis decreased estrone-3-sulfate uptake but had no effect on taurocholate or estradiol-17β-glucuronide transport. Based on inhibition studies and transport characteristics, three different transport mechanisms are suggested to be involved in the transport of taurocholate, estrone-3-sulfate and estradiol-17β-glucuronide across the ER membrane.
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Affiliation(s)
- Katrin Wlcek
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland.
| | - Lia Hofstetter
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland.
| | - Bruno Stieger
- Department of Clinical Pharmacology and Toxicology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland.
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Abstract
The SLC37 family members are endoplasmic reticulum (ER)-associated sugar-phosphate/phosphate (P(i)) exchangers. Three of the four members, SLC37A1, SLC37A2, and SLC37A4, function as Pi-linked glucose-6-phosphate (G6P) antiporters catalyzing G6P:P(i) and P(i):P(i) exchanges. The activity of SLC37A3 is unknown. SLC37A4, better known as the G6P transporter (G6PT), has been extensively characterized, functionally and structurally, and is the best characterized family member. G6PT contains 10 transmembrane helices with both N and C termini facing the cytoplasm. The primary in vivo function of the G6PT protein is to translocate G6P from the cytoplasm into the ER lumen where it couples with either the liver/kidney/intestine-restricted glucose-6-phosphatase-α (G6Pase-α or G6PC) or the ubiquitously expressed G6Pase-β (or G6PC3) to hydrolyze G6P to glucose and P(i). The G6PT/G6Pase-α complex maintains interprandial glucose homeostasis, and the G6PT/G6Pase-β complex maintains neutrophil energy homeostasis and functionality. G6PT is highly selective for G6P and is competitively inhibited by cholorogenic acid and its derivatives. Neither SLC37A1 nor SLC37A2 can couple functionally with G6Pase-α or G6Pase-β, and the antiporter activities of SLC37A1 or SLC37A2 are not inhibited by cholorogenic acid. Deficiencies in G6PT cause glycogen storage disease type Ib (GSD-Ib), a metabolic and immune disorder. To date, 91 separate SLC37A4 mutations, including 39 missense mutations, have been identified in GSD-Ib patients. Characterization of missense mutations has yielded valuable information on functionally important residues in the G6PT protein. The biological roles of the other SLC37 proteins remain to be determined and deficiencies have not yet been correlated to diseases.
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Affiliation(s)
- Janice Y Chou
- Section on Cellular Differentiation, Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA.
| | - Brian C Mansfield
- Section on Cellular Differentiation, Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA; Foundation Fighting Blindness, Columbia, Maryland, USA
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30
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Pathogenic mechanisms and clinical implications of congenital neutropenia syndromes. Curr Opin Allergy Clin Immunol 2013; 13:596-606. [DOI: 10.1097/aci.0000000000000014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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Carlin MP, Scherrer DZ, De Tommaso AMA, Bertuzzo CS, Steiner CE. Determining mutations in G6PC and SLC37A4 genes in a sample of Brazilian patients with glycogen storage disease types Ia and Ib. Genet Mol Biol 2013; 36:502-6. [PMID: 24385852 PMCID: PMC3873180 DOI: 10.1590/s1415-47572013000400007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2013] [Accepted: 10/11/2013] [Indexed: 01/01/2023] Open
Abstract
Glycogen storage disease (GSD) comprises a group of autosomal recessive disorders characterized by deficiency of the enzymes that regulate the synthesis or degradation of glycogen. Types Ia and Ib are the most prevalent; while the former is caused by deficiency of glucose-6-phosphatase (G6Pase), the latter is associated with impaired glucose-6-phosphate transporter, where the catalytic unit of G6Pase is located. Over 85 mutations have been reported since the cloning of G6PC and SLC37A4 genes. In this study, twelve unrelated patients with clinical symptoms suggestive of GSDIa and Ib were investigated by using genetic sequencing of G6PC and SLC37A4 genes, being three confirmed as having GSD Ia, and two with GSD Ib. In seven of these patients no mutations were detected in any of the genes. Five changes were detected in G6PC, including three known point mutations (p.G68R, p.R83C and p.Q347X) and two neutral mutations (c.432G > A and c.1176T > C). Four changes were found in SLC37A4: a known point mutation (p.G149E), a novel frameshift insertion (c.1338_1339insT), and two neutral mutations (c.1287G > A and c.1076-28C > T). The frequency of mutations in our population was similar to that observed in the literature, in which the mutation p.R83C is also the most frequent one. Analysis of both genes should be considered in the investigation of this condition. An alternative explanation to the negative results in this molecular study is the possibility of a misdiagnosis. Even with a careful evaluation based on laboratory and clinical findings, overlap with other types of GSD is possible, and further molecular studies should be indicated.
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Affiliation(s)
- Marcelo Paschoalete Carlin
- Departamento de Genética Médica, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Daniel Zanetti Scherrer
- Departamento de Genética Médica, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | | | - Carmen Silvia Bertuzzo
- Departamento de Genética Médica, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
| | - Carlos Eduardo Steiner
- Departamento de Genética Médica, Faculdade de Ciências Médicas, Universidade de Campinas, Campinas, SP, Brazil
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Chou JY, Sik Jun H, Mansfield BC. The SLC37 family of phosphate-linked sugar phosphate antiporters. Mol Aspects Med 2013; 34:601-11. [PMID: 23506893 DOI: 10.1016/j.mam.2012.05.010] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2011] [Accepted: 03/08/2012] [Indexed: 12/28/2022]
Abstract
The SLC37 family consists of four sugar-phosphate exchangers, A1, A2, A3, and A4, which are anchored in the endoplasmic reticulum (ER) membrane. The best characterized family member is SLC37A4, better known as the glucose-6-phosphate (G6P) transporter (G6PT). SLC37A1, SLC37A2, and G6PT function as phosphate (Pi)-linked G6P antiporters catalyzing G6P:Pi and Pi:Pi exchanges. The activity of SLC37A3 is unknown. G6PT translocates G6P from the cytoplasm into the lumen of the ER where it couples with either glucose-6-phosphatase-α (G6Pase-α) or G6Pase-β to hydrolyze intraluminal G6P to glucose and Pi. The functional coupling of G6PT with G6Pase-α maintains interprandial glucose homeostasis and the functional coupling of G6PT with G6Pase-β maintains neutrophil energy homeostasis and functionality. A deficiency in G6PT causes glycogen storage disease type Ib, an autosomal recessive disorder characterized by impaired glucose homeostasis, neutropenia, and neutrophil dysfunction. Neither SLC37A1 nor SLC37A2 can functionally couple with G6Pase-α or G6Pase-β, and there are no known disease associations for them or SLC37A3. Since only G6PT matches the characteristics of the physiological ER G6P transporter involved in blood glucose homeostasis and neutrophil energy metabolism, the biological roles for the other SLC37 proteins remain to be determined.
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Affiliation(s)
- Janice Y Chou
- Section on Cellular Differentiation, Program on Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
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Banka S, Newman WG. A clinical and molecular review of ubiquitous glucose-6-phosphatase deficiency caused by G6PC3 mutations. Orphanet J Rare Dis 2013; 8:84. [PMID: 23758768 PMCID: PMC3718741 DOI: 10.1186/1750-1172-8-84] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Accepted: 05/22/2013] [Indexed: 12/14/2022] Open
Abstract
The G6PC3 gene encodes the ubiquitously expressed glucose-6-phosphatase enzyme (G-6-Pase β or G-6-Pase 3 or G6PC3). Bi-allelic G6PC3 mutations cause a multi-system autosomal recessive disorder of G6PC3 deficiency (also called severe congenital neutropenia type 4, MIM 612541). To date, at least 57 patients with G6PC3 deficiency have been described in the literature. G6PC3 deficiency is characterized by severe congenital neutropenia, recurrent bacterial infections, intermittent thrombocytopenia in many patients, a prominent superficial venous pattern and a high incidence of congenital cardiac defects and uro-genital anomalies. The phenotypic spectrum of the condition is wide and includes rare manifestations such as maturation arrest of the myeloid lineage, a normocellular bone marrow, myelokathexis, lymphopaenia, thymic hypoplasia, inflammatory bowel disease, primary pulmonary hypertension, endocrine abnormalities, growth retardation, minor facial dysmorphism, skeletal and integument anomalies amongst others. Dursun syndrome is part of this extended spectrum. G6PC3 deficiency can also result in isolated non-syndromic severe neutropenia. G6PC3 mutations in result in reduced enzyme activity, endoplasmic reticulum stress response, increased rates of apoptosis of affected cells and dysfunction of neutrophil activity. In this review we demonstrate that loss of function in missense G6PC3 mutations likely results from decreased enzyme stability. The condition can be diagnosed by sequencing the G6PC3 gene. A number of G6PC3 founder mutations are known in various populations and a possible genotype-phenotype relationship also exists. G6PC3 deficiency should be considered as part of the differential diagnoses in any patient with unexplained congenital neutropenia. Treatment with G-CSF leads to improvement in neutrophil numbers, prevents infections and improves quality of life. Mildly affected patients can be managed with prophylactic antibiotics. Untreated G6PC3 deficiency can be fatal. Echocardiogram, renal and pelvic ultrasound scans should be performed in all cases of suspected or confirmed G6PC3 deficiency. Routine assessment should include biochemical profile, growth profile and monitoring for development of varicose veins or venous ulcers.
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Affiliation(s)
- Siddharth Banka
- Manchester Centre for Genomic Medicine, Institute of Human Development, University of Manchester, Manchester, UK.
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Du H, Liu L, Wang Y, Nakagawa Y, Lyzlov A, Lutfy K, Friedman TC, Peng X, Liu Y. Specific reduction of G6PT may contribute to downregulation of hepatic 11β-HSD1 in diabetic mice. J Mol Endocrinol 2013; 50:167-78. [PMID: 23267038 PMCID: PMC3763023 DOI: 10.1530/jme-12-0223] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Pre-receptor activation of glucocorticoids via 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1 (HSD11B1)) has been identified as an important mediator of the metabolic syndrome. Hexose-6-phosphate dehydrogenase (H6PDH) mediates 11β-HSD1 amplifying tissue glucocorticoid production by driving intracellular NADPH exposure to 11β-HSD1 and requires glucose-6-phosphate transporter (G6PT (SLC37A4)) to maintain its activity. However, the potential effects of G6PT on tissue glucocorticoid production in type 2 diabetes and obesity have not yet been defined. Here, we evaluated the possible role of G6PT antisense oligonucleotides (G6PT ASO) in the pre-receptor metabolism of glucocorticoids as related to glucose homeostasis and insulin tolerance by examining the production of 11β-HSD1 and H6PDH in both male db/+ and db/db mouse liver tissue. We observed that G6PT ASO treatment of db/db mice markedly reduced hepatic G6PT mRNA and protein levels and substantially diminished the activation of hepatic 11β-HSD1 and H6PDH. Reduction of G6pt expression was correlated with the suppression of both hepatic gluconeogenic enzymes G6Pase and PEPCK and corresponded to the improvement of hyperglycemia and insulin resistance in db/db mice. Addition of G6PT ASO to mouse hepa1-6 cells led to a dose-dependent decrease in 11B-Hsd1 production. Knockdown of G6PT with RNA interference also impaired 11B-Hsd1 expression and showed comparable effects to H6pdh siRNA on silencing of H6pdh and 11B-Hsd1 expression in these intact cells. These findings suggest that G6PT plays an important role in the modulation of pre-receptor activation of glucocorticoids and provides new insights into the role of G6PT in the development of type 2 diabetes.
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Affiliation(s)
- Hanze Du
- Division of Internal Medicine, Charles R. Drew University of Medicine and Science, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, California 90095, USA
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Multiple roles of glucose-6-phosphatases in pathophysiology. Biochim Biophys Acta Gen Subj 2013; 1830:2608-18. [DOI: 10.1016/j.bbagen.2012.12.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/11/2012] [Accepted: 12/13/2012] [Indexed: 12/28/2022]
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Boztug K, Klein C. Genetics and Pathophysiology of Severe Congenital Neutropenia Syndromes Unrelated to Neutrophil Elastase. Hematol Oncol Clin North Am 2013; 27:43-60, vii. [DOI: 10.1016/j.hoc.2012.11.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Charkoudian LK, Farrell BP, Khosla C. Natural product inhibitors of glucose-6-phosphate translocase. MEDCHEMCOMM 2012. [DOI: 10.1039/c2md20008b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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Pan CJ, Chen SY, Jun HS, Lin SR, Mansfield BC, Chou JY. SLC37A1 and SLC37A2 are phosphate-linked, glucose-6-phosphate antiporters. PLoS One 2011; 6:e23157. [PMID: 21949678 PMCID: PMC3176764 DOI: 10.1371/journal.pone.0023157] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2011] [Accepted: 07/07/2011] [Indexed: 11/25/2022] Open
Abstract
Blood glucose homeostasis between meals depends upon production of glucose within the endoplasmic reticulum (ER) of the liver and kidney by hydrolysis of glucose-6-phosphate (G6P) into glucose and phosphate (Pi). This reaction depends on coupling the G6P transporter (G6PT) with glucose-6-phosphatase-α (G6Pase-α). Only one G6PT, also known as SLC37A4, has been characterized, and it acts as a Pi-linked G6P antiporter. The other three SLC37 family members, predicted to be sugar-phosphate:Pi exchangers, have not been characterized functionally. Using reconstituted proteoliposomes, we examine the antiporter activity of the other SLC37 members along with their ability to couple with G6Pase-α. G6PT- and mock-proteoliposomes are used as positive and negative controls, respectively. We show that SLC37A1 and SLC37A2 are ER-associated, Pi-linked antiporters, that can transport G6P. Unlike G6PT, neither is sensitive to chlorogenic acid, a competitive inhibitor of physiological ER G6P transport, and neither couples to G6Pase-α. We conclude that three of the four SLC37 family members are functional sugar-phosphate antiporters. However, only G6PT/SLC37A4 matches the characteristics of the physiological ER G6P transporter, suggesting the other SLC37 proteins have roles independent of blood glucose homeostasis.
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Affiliation(s)
- Chi-Jiunn Pan
- Section on Cellular Differentiation, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Shih-Yin Chen
- Section on Cellular Differentiation, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Hyun Sik Jun
- Section on Cellular Differentiation, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Su Ru Lin
- Section on Cellular Differentiation, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Brian C. Mansfield
- Section on Cellular Differentiation, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Janice Y. Chou
- Section on Cellular Differentiation, Program in Developmental Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, United States of America
- * E-mail:
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Abstract
INTRODUCTION Glycogen storage disease (GSD) type Ia and Ib are disorders of impaired glucose homeostasis affecting the liver and kidney. GSD-Ib also affects neutrophils. Current dietary therapies cannot prevent long-term complications. In animal studies, recombinant adeno-associated virus (rAAV) vector-mediated gene therapy can correct or minimize multiple aspects of the disorders, offering hope for human gene therapy. AREAS COVERED A summary of recent progress in rAAV-mediated gene therapy for GSD-I; strategies to improve rAAV-mediated gene delivery, transduction efficiency and immune avoidance; and vector refinements that improve expression. EXPERT OPINION rAAV-mediated gene delivery to the liver can restore glucose homeostasis in preclinical models of GSD-I, but some long-term complications of the liver and kidney remain. Gene therapy for GSD-Ib is less advanced than for GSD-Ia and only transient correction of myeloid dysfunction has been achieved. A question remains as to whether a single rAAV vector can meet the expression efficiency and tropism required to treat all aspects of GSD-I, or if a multi-pronged approach is needed. An understanding of the strengths and weaknesses of rAAV vectors in the context of strategies to achieve efficient transduction of the liver, kidney and hematopoietic stem cells is required for treating GSD-I.
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Affiliation(s)
- Janice Y Chou
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Section on Cellular Differentiation, Program on Developmental Endocrinology and Genetics, Bethesda, MD 20892 1830, USA.
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Fioredda F, Calvillo M, Bonanomi S, Coliva T, Tucci F, Farruggia P, Pillon M, Martire B, Ghilardi R, Ramenghi U, Renga D, Menna G, Barone A, Lanciotti M, Dufour C. Congenital and acquired neutropenia consensus guidelines on diagnosis from the Neutropenia Committee of the Marrow Failure Syndrome Group of the AIEOP (Associazione Italiana Emato-Oncologia Pediatrica). Pediatr Blood Cancer 2011; 57:10-7. [PMID: 21448998 DOI: 10.1002/pbc.23108] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2010] [Accepted: 02/07/2011] [Indexed: 12/30/2022]
Abstract
Congenital and acquired neutropenia are rare disorders whose frequency in pediatric age may be underestimated due to remarkable differences in definition or misdiagnosed because of the lack of common practice guidelines. Neutropenia Committee of the Marrow Failure Syndrome Group (MFSG) of the AIEOP (Associazione Italiana Emato-Oncologia Pediatrica) elaborated this document following design and methodology formerly approved by the AIEOP board. The panel of experts reviewed the literature on the topic and participated in a conference producing a document which includes a classification of neutropenia and a comprehensive guideline on diagnosis of neutropenia.
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Klein C. Genetic defects in severe congenital neutropenia: emerging insights into life and death of human neutrophil granulocytes. Annu Rev Immunol 2011; 29:399-413. [PMID: 21219176 DOI: 10.1146/annurev-immunol-030409-101259] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The discovery of genetic defects causing congenital neutropenia has illuminated mechanisms controlling differentiation, circulation, and decay of neutrophil granulocytes. Deficiency of the mitochondrial proteins HAX1 and AK2 cause premature apoptosis of myeloid progenitor cells associated with dissipation of the mitochondrial membrane potential, whereas mutations in ELA2/ELANE and G6PC3 are associated with signs of increased endoplasmic reticulum stress. Mutations in the transcriptional repressor GFI1 and the cytoskeletal regulator WASP also lead to defective neutrophil production. This unexpected diversity of factors suggests that multiple pathways are involved in the pathogenesis of congenital neutropenia.
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Affiliation(s)
- Christoph Klein
- Department of Pediatric Hematology/Oncology, Hannover Medical School, Germany.
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Abstract
PURPOSE OF REVIEW To review recent advances in severe congenital neutropenia (SCN) syndromes. RECENT FINDINGS The majority of patients with SCN bear monoallelic mutations in the neutrophil elastase (ELANE) gene. Biallelic mutations in the antiapoptotic gene HAX1 were identified in patients with autosomal recessive SCN. G6PC3 deficiency is a syndromic variant of SCN associating congenital neutropenia with various developmental defects including cardiac or urogenital malformations. The pathophysiology of these distinct genetic variants of SCN is complex. Increased apoptosis of neutrophil granulocytes may be caused by various molecular mechanisms including destabilization of the mitochondrial membrane potential and/or activation of the so-called 'unfolded protein response'. SUMMARY SCN represents a heterogenous group of disorders that may be caused by genetic defects in ELANE, GFI1, HAX1, G6PC3 or activating mutations in the Wiskott-Aldrich syndrome (WAS) gene. Ongoing research will uncover additional genetic defects in SCN patients.
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Abstract
Glycogen storage disease type I (GSD-I) consists of two subtypes: GSD-Ia, a deficiency in glucose-6-phosphatase-α (G6Pase-α) and GSD-Ib, which is characterized by an absence of a glucose-6-phosphate (G6P) transporter (G6PT). A third disorder, G6Pase-β deficiency, shares similarities with this group of diseases. G6Pase-α and G6Pase-β are G6P hydrolases in the membrane of the endoplasmic reticulum, which depend on G6PT to transport G6P from the cytoplasm into the lumen. A functional complex of G6PT and G6Pase-α maintains interprandial glucose homeostasis, whereas G6PT and G6Pase-β act in conjunction to maintain neutrophil function and homeostasis. Patients with GSD-Ia and those with GSD-Ib exhibit a common metabolic phenotype of disturbed glucose homeostasis that is not evident in patients with G6Pase-β deficiency. Patients with a deficiency in G6PT and those lacking G6Pase-β display a common myeloid phenotype that is not shared by patients with GSD-Ia. Previous studies have shown that neutrophils express the complex of G6PT and G6Pase-β to produce endogenous glucose. Inactivation of either G6PT or G6Pase-β increases neutrophil apoptosis, which underlies, at least in part, neutrophil loss (neutropenia) and dysfunction in GSD-Ib and G6Pase-β deficiency. Dietary and/or granulocyte colony-stimulating factor therapies are available; however, many aspects of the diseases are still poorly understood. This Review will address the etiology of GSD-Ia, GSD-Ib and G6Pase-β deficiency and highlight advances in diagnosis and new treatment approaches, including gene therapy.
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Affiliation(s)
- Janice Y Chou
- Section on Cellular Differentiation, Program on Developmental Endocrinology and Genetics, Building 10, Room 9D42, 10 Center Drive, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892-1830, USA.
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Zappu A, Lilliu F, Podda RA, Loudianos G. Molecular analysis of glycogen storage disease type Ib in Sardinian population: evidence for a founder effect. Genet Test Mol Biomarkers 2010; 14:399-403. [PMID: 20578944 DOI: 10.1089/gtmb.2010.0024] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We describe epidemiological, genetic, and clinical data of the 1124-2del mutation in the G6PT gene, detected in homozygosity in three glycogen storage disease type Ib patients of Sardinian origin. This mutation was found to be associated with four sequence variations: c.593 A>T (p.N198I), c.625+19 C>T, c.1062 C>T (N354N), and c.1224 G>A (p.T408T) in the G6PT gene. RNA studies were performed for c.1124-2del and c.625+19 C>T. The c.1124-1del2 acceptor splicing mutation showed skipping of 31 nucleotides of exon 9 due to the activation of a downstream cryptic acceptor splice site in 1154-1155 nucleotide positions, resulting in a downstream stop codon at aa position 402. RNA analysis of c.625+19 C>T variation showed a small amount of alternative splicing with skipping of exon 4, resulting in a stop codon at aa position 211. Our cases present most of features of the severe form of disease, including early onset with chronic neutropenia, frequent infections, and inflammatory bowel disease. Our results suggest a founder effect for glycogen storage disease type Ib that facilitates diagnosis using mutation analysis, sparing patients from liver biopsy. DNA-based diagnosis will enable us to make accurate determination of carrier status and prenatal diagnosis, thus improving genetic counseling.
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Affiliation(s)
- Antonietta Zappu
- Dipartimento di Scienze Biomediche e Biotecnologie, USC, Cagliari, Italy
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Senesi S, Legeza B, Balázs Z, Csala M, Marcolongo P, Kereszturi E, Szelényi P, Egger C, Fulceri R, Mandl J, Giunti R, Odermatt A, Bánhegyi G, Benedetti A. Contribution of fructose-6-phosphate to glucocorticoid activation in the endoplasmic reticulum: possible implication in the metabolic syndrome. Endocrinology 2010; 151:4830-9. [PMID: 20826560 DOI: 10.1210/en.2010-0614] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Both fructose consumption and increased intracellular glucocorticoid activation have been implicated in the pathogenesis of the metabolic syndrome. Glucocorticoid activation by 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) depends on hexose-6-phosphate dehydrogenase (H6PD), which physically interacts with 11β-HSD1 at the luminal surface of the endoplasmic reticulum (ER) membrane and generates reduced nicotinamide adenine dinucleotide phosphate for the reduction of glucocorticoids. The reducing equivalents for the reaction are provided by glucose-6-phosphate (G6P) that is transported by G6P translocase into the ER. Here, we show that fructose-6-phosphate (F6P) can substitute for G6P and is sufficient to maintain reductase activity of 11β-HSD1 in isolated microsomes. Our findings indicate that the mechanisms of F6P and G6P transport across the ER membrane are distinct and provide evidence that F6P is converted to G6P in the ER lumen, thus yielding substrate for H6PD-dependent reduced nicotinamide adenine dinucleotide phosphate generation. Using the purified enzyme, we show that F6P cannot be directly dehydrogenated by H6PD, and we also excluded H6PD as a phosphohexose isomerase. Therefore, we postulate the existence of an ER luminal hexose-phosphate isomerase different from the cytosolic enzyme. The results suggest that cytosolic F6P promotes prereceptor glucocorticoid activation in white adipose tissue, which might have a role in the pathophysiology of the metabolic syndrome.
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Affiliation(s)
- Silvia Senesi
- Department of Pathophysiology, Experimental Medicine and Public Health, University of Siena, Siena, Italy
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Abstract
The lumen of the endoplasmic reticulum constitutes a separate intracellular compartment with a special proteome and metabolome. The redox conditions of the organelle are also characteristically different from those of the other subcellular compartments. The luminal environment has been considered more oxidizing than the cytosol due to the presence of oxidative protein folding. However, recent observations suggest that redox systems in reduced and oxidized states are present simultaneously. The concerted action of membrane transporters and oxidoreductase enzymes maintains the oxidized state of the thiol-disulfide and the reduced state of the pyridine nucleotide redox systems, which are prerequisites for the normal redox reactions localized in the organelle. The powerful thiol-oxidizing machinery of oxidative protein folding continuously challenges the local antioxidant defense. Alterations of the luminal redox conditions, either in oxidizing or reducing direction, affect protein processing, are sensed by the accumulation of misfolded/unfolded proteins, and may induce endoplasmic reticulum stress and unfolded protein response. The activated signaling pathways attempt to restore the balance between protein loading and processing and induce programmed cell death if these attempts fail. Recent findings strongly support the involvement of redox-based endoplasmic reticulum stress in a plethora of human diseases, either as causative agents or as complications.
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Affiliation(s)
- Miklós Csala
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
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Scales CD, Chandrashekar AS, Robinson MR, Cantor DA, Sullivan J, Haleblian GE, Leitao VA, Sur RL, Borawski KM, Koeberl D, Kishnani PS, Preminger GM. Stone forming risk factors in patients with type Ia glycogen storage disease. J Urol 2010; 183:1022-5. [PMID: 20092831 DOI: 10.1016/j.juro.2009.11.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2009] [Indexed: 10/19/2022]
Abstract
PURPOSE Patients with type Ia glycogen storage disease have an increased recurrent nephrolithiasis rate. We identified stone forming risk factors in patients with type Ia glycogen storage disease vs those in stone formers without the disease. MATERIALS AND METHODS Patients with type Ia glycogen storage disease were prospectively enrolled from our metabolic clinic. Patient 24-hour urine parameters were compared to those in age and gender matched stone forming controls. RESULTS We collected 24-hour urine samples from 13 patients with type Ia glycogen storage disease. Average +/- SD age was 27.0 +/- 13.0 years and 6 patients (46%) were male. Compared to age and gender matched hypocitraturic, stone forming controls patients had profound hypocitraturia (urinary citrate 70 vs 344 mg daily, p = 0.009). When comparing creatinine adjusted urinary values, patients had profound hypocitraturia (0.119 vs 0.291 mg/mg creatinine, p = 0.005) and higher oxalate (0.026 vs 0.021 mg/mg creatinine, p = 0.038) vs other stone formers. CONCLUSIONS Patients with type Ia glycogen storage disease have profound hypocitraturia, as evidenced by 24-hour urine collections, even compared to other stone formers. This may be related to a recurrent nephrolithiasis rate greater than in the overall population. These findings may be used to support different treatment modalities, timing and/or doses to prevent urinary lithiasis in patients with type Ia glycogen storage disease.
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Affiliation(s)
- Charles D Scales
- Division of Medical Genetics, Duke University Medical Center, Durham, North Carolina 27710, USA
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Abstract
PURPOSE OF REVIEW Glycogen storage disease type Ib, characterized by disturbed glucose homeostasis, neutropenia, and neutrophil dysfunction, is caused by a deficiency in a ubiquitously expressed glucose-6-phosphate transporter (G6PT). G6PT translocates glucose-6-phosphate (G6P) from the cytoplasm into the lumen of the endoplasmic reticulum, in which it is hydrolyzed to glucose either by a liver/kidney/intestine-restricted glucose-6-phosphatase-alpha (G6Pase-alpha) or by a ubiquitously expressed G6Pase-beta. The role of the G6PT/G6Pase-alpha complex is well established and readily explains why G6PT disruptions disturb interprandial blood glucose homeostasis. However, the basis for neutropenia and neutrophil dysfunction in glycogen storage disease type Ib is poorly understood. Recent studies that are now starting to unveil the mechanisms are presented in this review. RECENT FINDINGS Characterization of G6Pase-beta and generation of mice lacking either G6PT or G6Pase-beta have shown that neutrophils express the G6PT/G6Pase-beta complex capable of producing endogenous glucose. Loss of G6PT activity leads to enhanced endoplasmic reticulum stress, oxidative stress, and apoptosis that underlie neutropenia and neutrophil dysfunction in glycogen storage disease type Ib. SUMMARY Neutrophil function is intimately linked to the regulation of glucose and G6P metabolism by the G6PT/G6Pase-beta complex. Understanding the molecular mechanisms that govern energy homeostasis in neutrophils has revealed a previously unrecognized pathway of intracellular G6P metabolism in neutrophils.
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Affiliation(s)
- Janice Y Chou
- aProgram on Developmental Endocrinology and Genetics, Section on Cellular Differentiation, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-1830, USA.
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Boztug K, Klein C. Novel genetic etiologies of severe congenital neutropenia. Curr Opin Immunol 2009; 21:472-80. [PMID: 19782549 DOI: 10.1016/j.coi.2009.09.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2009] [Revised: 08/24/2009] [Accepted: 09/10/2009] [Indexed: 11/19/2022]
Abstract
Severe congenital neutropenia (SCN) comprises a heterogenous group of primary immunodeficiency disorders collectively characterized by paucity of mature neutrophils. In recent years, progress has been made with respect to the elucidation of genetic causes underlying syndromic and non-syndromic variants of SCN. Most cases of autosomal dominant SCN are associated with mutations in the neutrophil elastase (ELA-2/ELANE) gene, autosomal recessive forms of this disorder can be caused by mutations in the gene encoding the mitochondrial protein HAX-1. Rarely, SCN can be caused by mutations in the gene encoding the transcription factor GFI1 or activating mutations in the Wiskott-Aldrich syndrome (WAS) gene, respectively. More recently, a complex disorder associating SCN and developmental aberrations was identified, caused by mutations in the glucose-6-phosphatase catalytic subunit 3 (G6PC3) gene. Despite our increasing knowledge of the genetic etiologies of SCN, the molecular pathophysiology underlying these disorders remains only partially understood.
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Affiliation(s)
- Kaan Boztug
- Department of Pediatric Hematology/Oncology, Hannover Medical School, Carl-Neuberg-Strasse 1, D-30625 Hannover, Germany
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