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Zhang C, Gu L, Xie H, Liu Y, Huang P, Zhang J, Luo D, Zhang J. Glucose transport, transporters and metabolism in diabetic retinopathy. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166995. [PMID: 38142757 DOI: 10.1016/j.bbadis.2023.166995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 12/02/2023] [Accepted: 12/18/2023] [Indexed: 12/26/2023]
Abstract
Diabetic retinopathy (DR) is the most common reason for blindness in working-age individuals globally. Prolonged high blood glucose is a main causative factor for DR development, and glucose transport is prerequisite for the disturbances in DR caused by hyperglycemia. Glucose transport is mediated by its transporters, including the facilitated transporters (glucose transporter, GLUTs), the "active" glucose transporters (sodium-dependent glucose transporters, SGLTs), and the SLC50 family of uniporters (sugars will eventually be exported transporters, SWEETs). Glucose transport across the blood-retinal barrier (BRB) is crucial for nourishing the neuronal retina in the context of retinal physiology. This physiological process primarily relies on GLUTs and SGLTs, which mediate the glucose transportation across both the cell membrane of retinal capillary endothelial cells and the retinal pigment epithelium (RPE). Under diabetic conditions, increased accumulation of extracellular glucose enhances the retinal cellular glucose uptake and metabolism via both glycolysis and glycolytic side branches, which activates several biochemical pathways, including the protein kinase C (PKC), advanced glycation end-products (AGEs), polyol pathway and hexosamine biosynthetic pathway (HBP). These activated biochemical pathways further increase the production of reactive oxygen species (ROS), leading to oxidative stress and activation of Poly (ADP-ribose) polymerase (PARP). The activated PARP further affects all the cellular components in the retina, and finally resulting in microangiopathy, neurodegeneration and low-to-moderate grade inflammation in DR. This review aims to discuss the changes of glucose transport, glucose transporters, as well as its metabolism in DR, which influences the retinal neurovascular unit (NVU) and implies the possible therapeutic strategies for treating DR.
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Affiliation(s)
- Chaoyang Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Clinical Research Center for Eye Diseases; Shanghai Clinical Research Center for Eye Diseases; Shanghai Key Clinical Specialty; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai Eye Research Institute, Shanghai, China.
| | - Limin Gu
- Department of Ophthalmology, Shanghai Aier Eye Hospital, Shanghai, China.
| | - Hai Xie
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Clinical Research Center for Eye Diseases; Shanghai Clinical Research Center for Eye Diseases; Shanghai Key Clinical Specialty; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai Eye Research Institute, Shanghai, China.
| | - Yan Liu
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Clinical Research Center for Eye Diseases; Shanghai Clinical Research Center for Eye Diseases; Shanghai Key Clinical Specialty; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai Eye Research Institute, Shanghai, China.
| | - Peirong Huang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Clinical Research Center for Eye Diseases; Shanghai Clinical Research Center for Eye Diseases; Shanghai Key Clinical Specialty; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai Eye Research Institute, Shanghai, China.
| | - Jingting Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Clinical Research Center for Eye Diseases; Shanghai Clinical Research Center for Eye Diseases; Shanghai Key Clinical Specialty; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai Eye Research Institute, Shanghai, China.
| | - Dawei Luo
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Clinical Research Center for Eye Diseases; Shanghai Clinical Research Center for Eye Diseases; Shanghai Key Clinical Specialty; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai Eye Research Institute, Shanghai, China.
| | - Jingfa Zhang
- Department of Ophthalmology, Shanghai General Hospital (Shanghai First People's Hospital), Shanghai Jiao Tong University School of Medicine, Shanghai, China; National Clinical Research Center for Eye Diseases; Shanghai Clinical Research Center for Eye Diseases; Shanghai Key Clinical Specialty; Shanghai Key Laboratory of Ocular Fundus Diseases; Shanghai Engineering Center for Visual Science and Photomedicine; Shanghai Engineering Center for Precise Diagnosis and Treatment of Eye Diseases, Shanghai Eye Research Institute, Shanghai, China.
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2
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Trepiccione F, Iervolino A, D'Acierno M, Siccardi S, Costanzo V, Sardella D, De La Motte LR, D'Apolito L, Miele A, Perna AF, Capolongo G, Zacchia M, Frische S, Nielsen R, Staiano L, Sambri I, De Cegli R, Unwin R, Eladari D, Capasso G. The SGLT2 inhibitor dapagliflozin improves kidney function in glycogen storage disease XI. Sci Transl Med 2023; 15:eabn4214. [PMID: 37910600 DOI: 10.1126/scitranslmed.abn4214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 10/10/2023] [Indexed: 11/03/2023]
Abstract
Glycogen storage disease XI, also known as Fanconi-Bickel syndrome (FBS), is a rare autosomal recessive disorder caused by mutations in the SLC2A2 gene that encodes the glucose-facilitated transporter type 2 (GLUT2). Patients develop a life-threatening renal proximal tubule dysfunction for which no treatment is available apart from electrolyte replacement. To investigate the renal pathogenesis of FBS, SLC2A2 expression was ablated in mouse kidney and HK-2 proximal tubule cells. GLUT2Pax8Cre+ mice developed time-dependent glycogen accumulation in proximal tubule cells and recapitulated the renal Fanconi phenotype seen in patients. In vitro suppression of GLUT2 impaired lysosomal autophagy as shown by transcriptomic and biochemical analysis. However, this effect was reversed by exposure to a low glucose concentration, suggesting that GLUT2 facilitates the homeostasis of key cellular pathways in proximal tubule cells by preventing glucose toxicity. To investigate whether targeting proximal tubule glucose influx can limit glycogen accumulation and correct symptoms in vivo, we treated mice with the selective SGLT2 inhibitor dapagliflozin. Dapagliflozin reduced glycogen accumulation and improved metabolic acidosis and phosphaturia in the animals by normalizing the expression of Napi2a and NHE3 transporters. In addition, in a patient with FBS, dapagliflozin was safe, improved serum potassium and phosphate concentrations, and reduced glycogen content in urinary shed cells. Overall, this study provides proof of concept for dapagliflozin as a potentially suitable therapy for FBS.
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Affiliation(s)
- Francesco Trepiccione
- Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli," 80131 Naples, Italy
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Anna Iervolino
- Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli," 80131 Naples, Italy
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | | | - Sabrina Siccardi
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Vincenzo Costanzo
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Donato Sardella
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Luigi R De La Motte
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Luciano D'Apolito
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Antonio Miele
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
| | - Alessandra F Perna
- Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli," 80131 Naples, Italy
| | - Giovanna Capolongo
- Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli," 80131 Naples, Italy
| | - Miriam Zacchia
- Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli," 80131 Naples, Italy
| | | | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Leopoldo Staiano
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
- Institute for Genetic and Biomedical Research, National Research Council (CNR), 20089 Milan, Italy
| | - Irene Sambri
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
- Department of Medical and Translational Science, Federico II University, 80131 Naples, Italy
| | - Rossella De Cegli
- Telethon Institute of Genetics and Medicine (TIGEM), 80078 Pozzuoli, Italy
| | - Robert Unwin
- UCL Department of Renal Medicine, Royal Free Hospital, London NW3 2PF, UK
| | - Dominique Eladari
- Service de Médecine de Précision des maladies Métaboliques et Rénales, CHU Amiens-Picardie, Université de Picardie Jules Verne, 80054 Amiens, France
- FCRIN-INI-CRCT, 54500 Vandœuvre-lès-Nancy, France
- Paris Cardiovascular Research Center (PARCC), INSERM U970, F-75015, Paris, France
| | - Giovambattista Capasso
- Department of Medical Translational Sciences, University of Campania "Luigi Vanvitelli," 80131 Naples, Italy
- Biogem, Institute of Molecular Biology and Genetics, 83031 Ariano Irpino, Italy
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3
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Höppner J, Kornak U, Sinningen K, Rutsch F, Oheim R, Grasemann C. Autosomal recessive hypophosphatemic rickets type 2 (ARHR2) due to ENPP1-deficiency. Bone 2021; 153:116111. [PMID: 34252603 DOI: 10.1016/j.bone.2021.116111] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 07/01/2021] [Accepted: 07/06/2021] [Indexed: 12/25/2022]
Abstract
Awareness for hypophosphatemic rickets has increased in the last years, based on the availability of specific medical treatments. Autosomal recessive hypophosphatemic rickets type 2 (ARHR2) is a rare form of hypophosphatemic rickets, which is known to develop in survivors of generalized arterial calcification of infancy (GACI). Both disorders are based on a deficiency of ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1) and present with a high clinical variability and a lack of a phenotype-genotype association. ARHR2 is characterized by phosphate wasting due to elevated fibroblast growth factor 23 (FGF23) levels and might represent a response of the organism to minimize ectopic calcification in individuals with ENPP1-deficiency. This report reviews the recent clinical and preclinical data on this ultra-rare disease in childhood.
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Affiliation(s)
- Jakob Höppner
- Center for Rare Diseases Ruhr CeSER, Ruhr-University Bochum and Witten/Herdecke University, Germany; Department of Pediatrics, St.-Josef Hospital Bochum, Ruhr-University Bochum, Bochum, Germany
| | - Uwe Kornak
- Institute for Human Genetics, Universitätsmedizin Göttingen, Göttingen, Germany
| | - Kathrin Sinningen
- Department of Pediatrics, St.-Josef Hospital Bochum, Ruhr-University Bochum, Bochum, Germany
| | - Frank Rutsch
- Department of General Pediatrics, Münster University Children's Hospital, Münster, Germany
| | - Ralf Oheim
- Department of Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Corinna Grasemann
- Center for Rare Diseases Ruhr CeSER, Ruhr-University Bochum and Witten/Herdecke University, Germany; Department of Pediatrics, St.-Josef Hospital Bochum, Ruhr-University Bochum, Bochum, Germany.
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4
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Sharari S, Abou-Alloul M, Hussain K, Ahmad Khan F. Fanconi-Bickel Syndrome: A Review of the Mechanisms That Lead to Dysglycaemia. Int J Mol Sci 2020; 21:E6286. [PMID: 32877990 PMCID: PMC7504390 DOI: 10.3390/ijms21176286] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 07/30/2020] [Accepted: 08/02/2020] [Indexed: 12/13/2022] Open
Abstract
Accumulation of glycogen in the kidney and liver is the main feature of Fanconi-Bickel Syndrome (FBS), a rare disorder of carbohydrate metabolism inherited in an autosomal recessive manner due to SLC2A2 gene mutations. Missense, nonsense, frame-shift (fs), in-frame indels, splice site, and compound heterozygous variants have all been identified in SLC2A2 gene of FBS cases. Approximately 144 FBS cases with 70 different SLC2A2 gene variants have been reported so far. SLC2A2 encodes for glucose transporter 2 (GLUT2) a low affinity facilitative transporter of glucose mainly expressed in tissues playing important roles in glucose homeostasis, such as renal tubular cells, enterocytes, pancreatic β-cells, hepatocytes and discrete regions of the brain. Dysfunctional mutations and decreased GLUT2 expression leads to dysglycaemia (fasting hypoglycemia, postprandial hyperglycemia, glucose intolerance, and rarely diabetes mellitus), hepatomegaly, galactose intolerance, rickets, and poor growth. The molecular mechanisms of dysglycaemia in FBS are still not clearly understood. In this review, we discuss the physiological roles of GLUT2 and the pathophysiology of mutants, highlight all of the previously reported SLC2A2 mutations associated with dysglycaemia, and review the potential molecular mechanisms leading to dysglycaemia and diabetes mellitus in FBS patients.
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Affiliation(s)
- Sanaa Sharari
- Division of Biological and Biomedical Sciences, College of Health & Life Sciences, Hamad Bin Khalifa University, Qatar Foundation, Education City, Doha, Qatar;
- Department of Pediatric Medicine, Division of Endocrinology, Sidra Medicine, Doha, Qatar;
| | - Mohamad Abou-Alloul
- Department of Pediatric Medicine, Saida Governmental University Hospital, Beirut Arab University, Beirut 115020, Lebanon;
| | - Khalid Hussain
- Department of Pediatric Medicine, Division of Endocrinology, Sidra Medicine, Doha, Qatar;
| | - Faiyaz Ahmad Khan
- Department of Pediatric Medicine, Division of Endocrinology, Sidra Medicine, Doha, Qatar;
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5
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Gyimesi G, Pujol-Giménez J, Kanai Y, Hediger MA. Sodium-coupled glucose transport, the SLC5 family, and therapeutically relevant inhibitors: from molecular discovery to clinical application. Pflugers Arch 2020; 472:1177-1206. [PMID: 32767111 PMCID: PMC7462921 DOI: 10.1007/s00424-020-02433-x] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/24/2020] [Accepted: 07/02/2020] [Indexed: 02/06/2023]
Abstract
Sodium glucose transporters (SGLTs) belong to the mammalian solute carrier family SLC5. This family includes 12 different members in human that mediate the transport of sugars, vitamins, amino acids, or smaller organic ions such as choline. The SLC5 family belongs to the sodium symporter family (SSS), which encompasses transporters from all kingdoms of life. It furthermore shares similarity to the structural fold of the APC (amino acid-polyamine-organocation) transporter family. Three decades after the first molecular identification of the intestinal Na+-glucose cotransporter SGLT1 by expression cloning, many new discoveries have evolved, from mechanistic analysis to molecular genetics, structural biology, drug discovery, and clinical applications. All of these advances have greatly influenced physiology and medicine. While SGLT1 is essential for fast absorption of glucose and galactose in the intestine, the expression of SGLT2 is largely confined to the early part of the kidney proximal tubules, where it reabsorbs the bulk part of filtered glucose. SGLT2 has been successfully exploited by the pharmaceutical industry to develop effective new drugs for the treatment of diabetic patients. These SGLT2 inhibitors, termed gliflozins, also exhibit favorable nephroprotective effects and likely also cardioprotective effects. In addition, given the recent finding that SGLT2 is also expressed in tumors of pancreas and prostate and in glioblastoma, this opens the door to potential new therapeutic strategies for cancer treatment by specifically targeting SGLT2. Likewise, further discoveries related to the functional association of other SGLTs of the SLC5 family to human pathologies will open the door to potential new therapeutic strategies. We furthermore hope that the herein summarized information about the physiological roles of SGLTs and the therapeutic benefits of the gliflozins will be useful for our readers to better understand the molecular basis of the beneficial effects of these inhibitors, also in the context of the tubuloglomerular feedback (TGF), and the renin-angiotensin system (RAS). The detailed mechanisms underlying the clinical benefits of SGLT2 inhibition by gliflozins still warrant further investigation that may serve as a basis for future drug development.
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Affiliation(s)
- Gergely Gyimesi
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension, and Department of Biomedical Research, Inselspital, University of Bern, Kinderklinik, Office D845, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Jonai Pujol-Giménez
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension, and Department of Biomedical Research, Inselspital, University of Bern, Kinderklinik, Office D845, Freiburgstrasse 15, CH-3010, Bern, Switzerland
| | - Yoshikatsu Kanai
- Department of Bio-system Pharmacology, Graduate School of Medicine, Osaka University, Osaka, Japan
| | - Matthias A Hediger
- Membrane Transport Discovery Lab, Department of Nephrology and Hypertension, and Department of Biomedical Research, Inselspital, University of Bern, Kinderklinik, Office D845, Freiburgstrasse 15, CH-3010, Bern, Switzerland.
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6
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Ion Transporters, Channelopathies, and Glucose Disorders. Int J Mol Sci 2019; 20:ijms20102590. [PMID: 31137773 PMCID: PMC6566632 DOI: 10.3390/ijms20102590] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Revised: 05/21/2019] [Accepted: 05/22/2019] [Indexed: 01/19/2023] Open
Abstract
Ion channels and transporters play essential roles in excitable cells including cardiac, skeletal and smooth muscle cells, neurons, and endocrine cells. In pancreatic beta-cells, for example, potassium KATP channels link the metabolic signals generated inside the cell to changes in the beta-cell membrane potential, and ultimately regulate insulin secretion. Mutations in the genes encoding some ion transporter and channel proteins lead to disorders of glucose homeostasis (hyperinsulinaemic hypoglycaemia and different forms of diabetes mellitus). Pancreatic KATP, Non-KATP, and some calcium channelopathies and MCT1 transporter defects can lead to various forms of hyperinsulinaemic hypoglycaemia (HH). Mutations in the genes encoding the pancreatic KATP channels can also lead to different types of diabetes (including neonatal diabetes mellitus (NDM) and Maturity Onset Diabetes of the Young, MODY), and defects in the solute carrier family 2 member 2 (SLC2A2) leads to diabetes mellitus as part of the Fanconi–Bickel syndrome. Variants or polymorphisms in some ion channel genes and transporters have been reported in association with type 2 diabetes mellitus.
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7
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Enogieru OJ, Ung PMU, Yee SW, Schlessinger A, Giacomini KM. Functional and structural analysis of rare SLC2A2 variants associated with Fanconi-Bickel syndrome and metabolic traits. Hum Mutat 2019; 40:983-995. [PMID: 30950137 DOI: 10.1002/humu.23758] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 03/01/2019] [Accepted: 03/23/2019] [Indexed: 02/06/2023]
Abstract
Deleterious variants in SLC2A2 cause Fanconi-Bickel Syndrome (FBS), a glycogen storage disorder, whereas less common variants in SLC2A2 associate with numerous metabolic diseases. Phenotypic heterogeneity in FBS has been observed, but its causes remain unknown. Our goal was to functionally characterize rare SLC2A2 variants found in FBS and metabolic disease-associated variants to understand the impact of these variants on GLUT2 activity and expression and establish genotype-phenotype correlations. Complementary RNA-injected Xenopus laevis oocytes were used to study mutant transporter activity and membrane expression. GLUT2 homology models were constructed for mutation analysis using GLUT1, GLUT3, and XylE as templates. Seventeen FBS variants were characterized. Only c.457_462delCTTATA (p.Leu153_Ile154del) exhibited residual glucose uptake. Functional characterization revealed that only half of the variants were expressed on the plasma membrane. Most less common variants (except c.593 C>A (p.Thr198Lys) and c.1087 G>T (p.Ala363Ser)) exhibited similar GLUT2 transport activity as the wild type. Structural analysis of GLUT2 revealed that variants affect substrate-binding, steric hindrance, or overall transporter structure. The mutant transporter that is associated with a milder FBS phenotype, p.Leu153_Ile154del, retained transport activity. These results improve our overall understanding of the underlying causes of FBS and impact of GLUT2 function on various clinical phenotypes ranging from rare to common disease.
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Affiliation(s)
- Osatohanmwen J Enogieru
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California
| | - Peter M U Ung
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Sook Wah Yee
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California
| | - Avner Schlessinger
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Kathleen M Giacomini
- Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, San Francisco, California.,Institute for Human Genetics, University of California, San Francisco, San Francisco, California
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Wagner CA, Rubio-Aliaga I, Hernando N. Renal phosphate handling and inherited disorders of phosphate reabsorption: an update. Pediatr Nephrol 2019; 34:549-559. [PMID: 29275531 DOI: 10.1007/s00467-017-3873-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/08/2017] [Accepted: 12/12/2017] [Indexed: 01/12/2023]
Abstract
Renal phosphate handling critically determines plasma phosphate and whole body phosphate levels. Filtered phosphate is mostly reabsorbed by Na+-dependent phosphate transporters located in the brush border membrane of the proximal tubule: NaPi-IIa (SLC34A1), NaPi-IIc (SLC34A3), and Pit-2 (SLC20A2). Here we review new evidence for the role and relevance of these transporters in inherited disorders of renal phosphate handling. The importance of NaPi-IIa and NaPi-IIc for renal phosphate reabsorption and mineral homeostasis has been highlighted by the identification of mutations in these transporters in a subset of patients with infantile idiopathic hypercalcemia and patients with hereditary hypophosphatemic rickets with hypercalciuria. Both diseases are characterized by disturbed calcium homeostasis secondary to elevated 1,25-(OH)2 vitamin D3 as a consequence of hypophosphatemia. In vitro analysis of mutated NaPi-IIa or NaPi-IIc transporters suggests defective trafficking underlying disease in most cases. Monoallelic pathogenic mutations in both SLC34A1 and SLC34A3 appear to be very frequent in the general population and have been associated with kidney stones. Consistent with these findings, results from genome-wide association studies indicate that variants in SLC34A1 are associated with a higher risk to develop kidney stones and chronic kidney disease, but underlying mechanisms have not been addressed to date.
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Affiliation(s)
- Carsten A Wagner
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland. .,National Center for Competence in Research (NCCR) Kidney.CH, Zurich, Switzerland.
| | - Isabel Rubio-Aliaga
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,National Center for Competence in Research (NCCR) Kidney.CH, Zurich, Switzerland
| | - Nati Hernando
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, 8057, Zurich, Switzerland.,National Center for Competence in Research (NCCR) Kidney.CH, Zurich, Switzerland
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Bergwitz C, Miyamoto KI. Hereditary hypophosphatemic rickets with hypercalciuria: pathophysiology, clinical presentation, diagnosis and therapy. Pflugers Arch 2018; 471:149-163. [PMID: 30109410 DOI: 10.1007/s00424-018-2184-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 07/06/2018] [Accepted: 07/10/2018] [Indexed: 12/24/2022]
Abstract
Hereditary hypophosphatemic rickets with hypercalciuria (HHRH; OMIM: 241530) is a rare autosomal recessive disorder with an estimated prevalence of 1:250,000 that was originally described by Tieder et al. Individuals with HHRH carry compound-heterozygous or homozygous (comp/hom) loss-of-function mutations in the sodium-phosphate co-transporter NPT2c. These mutations result in the development of urinary phosphate (Pi) wasting and hypophosphatemic rickets, bowing, and short stature, as well as appropriately elevated 1,25(OH)2D levels, which sets this fibroblast growth factor 23 (FGF23)-independent disorder apart from the more common X-linked hypophosphatemia. The elevated 1,25(OH)2D levels in turn result in hypercalciuria due to enhanced intestinal calcium absorption and reduced parathyroid hormone (PTH)-dependent calcium-reabsorption in the distal renal tubules, leading to the development of kidney stones and/or nephrocalcinosis in approximately half of the individuals with HHRH. Even heterozygous NPT2c mutations are frequently associated with isolated hypercalciuria (IH), which increases the risk of kidney stones or nephrocalcinosis threefold in affected individuals compared with the general population. Bone disease is generally absent in individuals with IH, in contrast to those with HHRH. Treatment of HHRH and IH consists of monotherapy with oral Pi supplements, while active vitamin D analogs are contraindicated, mainly because the endogenous 1,25(OH)2D levels are already elevated but also to prevent further worsening of the hypercalciuria. Long-term studies to determine whether oral Pi supplementation alone is sufficient to prevent renal calcifications and bone loss, however, are lacking. It is also unknown how therapy should be monitored, whether secondary hyperparathyroidism can develop, and whether Pi requirements decrease with age, as observed in some FGF23-dependent hypophosphatemic disorders, or whether this can lead to osteoporosis.
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Affiliation(s)
- Clemens Bergwitz
- Section Endocrinology and Metabolism, Yale University School of Medicine, Anlyan Center, Office S117, Lab S110, 1 Gilbert Street, New Haven, CT 06519, USA.
| | - Ken-Ichi Miyamoto
- Department of Molecular Nutrition, Tokushima University Graduate School of Biomedical Sciences, Tokushima, Japan
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10
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Pogoriler J, O'Neill AF, Voss SD, Shamberger RC, Perez-Atayde AR. Hepatocellular Carcinoma in Fanconi-Bickel Syndrome. Pediatr Dev Pathol 2018; 21:84-90. [PMID: 28382841 DOI: 10.1177/1093526617693540] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Fanconi-Bickel syndrome is a rare autosomal recessive disorder due to mutations in the facilitative glucose transporter 2 ( GLUT2 or SLC2A2) gene resulting in excessive glycogen storage predominantly in the liver and kidney. Previous case reports of this condition have described liver biopsies with glycogen storage and variable steatosis and/or fibrosis. Unlike in other types of glycogen storage disease, hepatocellular adenomas and carcinomas have not been described to date in this syndrome. A 6-year-old boy with consanguineous parents had short stature, poorly controlled rickets, hepatosplenomegaly, and renal tubular dysfunction clinically consistent with Fanconi-Bickel Syndrome. Sequencing of the SLC2A2 gene showed a homozygous variant of unknown significance [c.474A > C (p.Arg158Ser)] causing a missense mutation in an evolutionarily conserved residue. An incidental single hepatic lesion was discovered on imaging, and subsequent resection showed a 2.6 cm well-differentiated hepatocellular carcinoma with moderate atypia, diffuse immunoreactivity for glypican-3, and nuclear b-catenin, and with focal complete loss of the reticulin framework. The non-neoplastic liver showed marked glycogen accumulation with mild periportal fibrosis, rare bridging fibrosis, and no regenerative or adenomatous nodules. By electron microscopy, tumor cells had pleomorphic nuclei, prominent nucleoli, and scant cytoplasm with numerous mitochondria. Well-developed canaliculi were occasionally seen. The non-neoplastic liver showed glycogenosis with abundant cytoplasmic free (non-membrane bound) glycogen. Hepatocellular carcinoma should be considered as a possible complication of Fanconi-Bickel syndrome. This well differentiated carcinoma did not appear to be associated with hepatic adenomatosis as has been described in some hepatocellular carcinomas associated with other hepatic glycogen storage disorders. The nuclear beta-catenin immunoreactivity indicates a role for the Wnt signaling pathway in the pathogenesis of this tumor.
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Affiliation(s)
- Jennifer Pogoriler
- 1 Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Allison F O'Neill
- 2 Division of Pediatric Oncology, Dana Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Stephan D Voss
- 3 Department of Radiology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Robert C Shamberger
- 4 Department of Surgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
| | - Antonio R Perez-Atayde
- 1 Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA
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Abstract
BACKGROUND Fanconi Bickel Syndrome is a rare, autosomal recessive, disorder of carbohydrate metabolism. Presence of hypercalciuria is rare. CASE CHARACTERISTICS 4.5-years-old boy presented with growth failure, hepatomegaly, rickets, fasting hypoglycemia with postprandial hyperglycemia, fanconi syndrome and hypercalciuria. OUTCOME A rare mutation in GLUT-2 gene suggestive of Fanconi Bickel Syndrome. MESSAGE Fanconi Bickel Syndrome may present with hypercalciuria with proximal renal tubulopathy along with fasting hypoglycemia and postprandial hyperglycemia.
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12
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Oliveira B, Kleta R, Bockenhauer D, Walsh SB. Genetic, pathophysiological, and clinical aspects of nephrocalcinosis. Am J Physiol Renal Physiol 2016; 311:F1243-F1252. [DOI: 10.1152/ajprenal.00211.2016] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 09/06/2016] [Indexed: 12/25/2022] Open
Abstract
Nephrocalcinosis describes the ectopic deposition of calcium salts in the kidney parenchyma. Nephrocalcinosis can result from a number of acquired causes but also an even greater number of genetic diseases, predominantly renal but also extrarenal. Here we provide a review of the genetic causes of nephrocalcinosis, along with putative mechanisms, illustrated by human and animal data.
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Affiliation(s)
- Ben Oliveira
- University College London, Centre for Nephrology, London, United Kingdom
| | - Robert Kleta
- University College London, Centre for Nephrology, London, United Kingdom
| | - Detlef Bockenhauer
- University College London, Centre for Nephrology, London, United Kingdom
| | - Stephen B. Walsh
- University College London, Centre for Nephrology, London, United Kingdom
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Gupta N, Nambam B, Weinstein DA, Shoemaker LR. Late Diagnosis of Fanconi-Bickel Syndrome. JOURNAL OF INBORN ERRORS OF METABOLISM AND SCREENING 2016. [DOI: 10.1177/2326409816679430] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Affiliation(s)
- Nirupama Gupta
- Division of Nephrology, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Bimota Nambam
- Division of Endocrinology, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - David A. Weinstein
- Glycogen Storage Disease Program, Department of Pediatrics, University of Florida, Gainesville, FL, USA
| | - Lawrence R. Shoemaker
- Division of Nephrology, Department of Pediatrics, University of Florida, Gainesville, FL, USA
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Yang Y, Chan L. Monogenic Diabetes: What It Teaches Us on the Common Forms of Type 1 and Type 2 Diabetes. Endocr Rev 2016; 37:190-222. [PMID: 27035557 PMCID: PMC4890265 DOI: 10.1210/er.2015-1116] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
To date, more than 30 genes have been linked to monogenic diabetes. Candidate gene and genome-wide association studies have identified > 50 susceptibility loci for common type 1 diabetes (T1D) and approximately 100 susceptibility loci for type 2 diabetes (T2D). About 1-5% of all cases of diabetes result from single-gene mutations and are called monogenic diabetes. Here, we review the pathophysiological basis of the role of monogenic diabetes genes that have also been found to be associated with common T1D and/or T2D. Variants of approximately one-third of monogenic diabetes genes are associated with T2D, but not T1D. Two of the T2D-associated monogenic diabetes genes-potassium inward-rectifying channel, subfamily J, member 11 (KCNJ11), which controls glucose-stimulated insulin secretion in the β-cell; and peroxisome proliferator-activated receptor γ (PPARG), which impacts multiple tissue targets in relation to inflammation and insulin sensitivity-have been developed as major antidiabetic drug targets. Another monogenic diabetes gene, the preproinsulin gene (INS), is unique in that INS mutations can cause hyperinsulinemia, hyperproinsulinemia, neonatal diabetes mellitus, one type of maturity-onset diabetes of the young (MODY10), and autoantibody-negative T1D. Dominant heterozygous INS mutations are the second most common cause of permanent neonatal diabetes. Moreover, INS gene variants are strongly associated with common T1D (type 1a), but inconsistently with T2D. Variants of the monogenic diabetes gene Gli-similar 3 (GLIS3) are associated with both T1D and T2D. GLIS3 is a key transcription factor in insulin production and β-cell differentiation during embryonic development, which perturbation forms the basis of monogenic diabetes as well as its association with T1D. GLIS3 is also required for compensatory β-cell proliferation in adults; impairment of this function predisposes to T2D. Thus, monogenic forms of diabetes are invaluable "human models" that have contributed to our understanding of the pathophysiological basis of common T1D and T2D.
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Affiliation(s)
- Yisheng Yang
- Division of Endocrinology (Y.Y.), Department of Medicine, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio 44109; and Diabetes and Endocrinology Research Center (L.C.), Division of Diabetes, Endocrinology and Metabolism, Departments of Medicine, Molecular and Cellular Biology, Biochemistry and Molecular Biology, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
| | - Lawrence Chan
- Division of Endocrinology (Y.Y.), Department of Medicine, MetroHealth Medical Center, Case Western Reserve University, Cleveland, Ohio 44109; and Diabetes and Endocrinology Research Center (L.C.), Division of Diabetes, Endocrinology and Metabolism, Departments of Medicine, Molecular and Cellular Biology, Biochemistry and Molecular Biology, and Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas 77030
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Abstract
The glucose transporter isoform GLUT2 is expressed in liver, intestine, kidney and pancreatic islet beta cells, as well as in the central nervous system, in neurons, astrocytes and tanycytes. Physiological studies of genetically modified mice have revealed a role for GLUT2 in several regulatory mechanisms. In pancreatic beta cells, GLUT2 is required for glucose-stimulated insulin secretion. In hepatocytes, suppression of GLUT2 expression revealed the existence of an unsuspected glucose output pathway that may depend on a membrane traffic-dependent mechanism. GLUT2 expression is nevertheless required for the physiological control of glucose-sensitive genes, and its inactivation in the liver leads to impaired glucose-stimulated insulin secretion, revealing a liver-beta cell axis, which is likely to be dependent on bile acids controlling beta cell secretion capacity. In the nervous system, GLUT2-dependent glucose sensing controls feeding, thermoregulation and pancreatic islet cell mass and function, as well as sympathetic and parasympathetic activities. Electrophysiological and optogenetic techniques established that Glut2 (also known as Slc2a2)-expressing neurons of the nucleus tractus solitarius can be activated by hypoglycaemia to stimulate glucagon secretion. In humans, inactivating mutations in GLUT2 cause Fanconi-Bickel syndrome, which is characterised by hepatomegaly and kidney disease; defects in insulin secretion are rare in adult patients, but GLUT2 mutations cause transient neonatal diabetes. Genome-wide association studies have reported that GLUT2 variants increase the risks of fasting hyperglycaemia, transition to type 2 diabetes, hypercholesterolaemia and cardiovascular diseases. Individuals with a missense mutation in GLUT2 show preference for sugar-containing foods. We will discuss how studies in mice help interpret the role of GLUT2 in human physiology.
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Affiliation(s)
- Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, Genopode Building, 1015, Lausanne, Switzerland,
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Tatsumi S, Kaneko I, Segawa H, Miyamoto K. Inorganic phosphate homeostasis: crosstalk between kidney and other organs. ACTA ACUST UNITED AC 2014. [DOI: 10.2745/dds.29.408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Sawako Tatsumi
- Department of Molecular Nutrition Institute of Health Biosciences, The University of Tokushima Graduate School
| | - Ichiro Kaneko
- Department of Molecular Nutrition Institute of Health Biosciences, The University of Tokushima Graduate School
| | - Hiroko Segawa
- Department of Molecular Nutrition Institute of Health Biosciences, The University of Tokushima Graduate School
| | - Kenichi Miyamoto
- Department of Molecular Nutrition Institute of Health Biosciences, The University of Tokushima Graduate School
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