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Diederich J, Mounkoro P, Tirado HA, Chevalier N, Van Schaftingen E, Veiga-da-Cunha M. SGLT5 is the renal transporter for 1,5-anhydroglucitol, a major player in two rare forms of neutropenia. Cell Mol Life Sci 2023; 80:259. [PMID: 37594549 PMCID: PMC10439028 DOI: 10.1007/s00018-023-04884-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 06/20/2023] [Accepted: 07/17/2023] [Indexed: 08/19/2023]
Abstract
Neutropenia and neutrophil dysfunction in glycogen storage disease type 1b (GSD1b) and severe congenital neutropenia type 4 (SCN4), associated with deficiencies of the glucose-6-phosphate transporter (G6PT/SLC37A4) and the phosphatase G6PC3, respectively, are the result of the accumulation of 1,5-anhydroglucitol-6-phosphate in neutrophils. This is an inhibitor of hexokinase made from 1,5-anhydroglucitol (1,5-AG), an abundant polyol in blood. 1,5-AG is presumed to be reabsorbed in the kidney by a sodium-dependent-transporter of uncertain identity, possibly SGLT4/SLC5A9 or SGLT5/SLC5A10. Lowering blood 1,5-AG with an SGLT2-inhibitor greatly improved neutrophil counts and function in G6PC3-deficient and GSD1b patients. Yet, this effect is most likely mediated indirectly, through the inhibition of the renal 1,5-AG transporter by glucose, when its concentration rises in the renal tubule following inhibition of SGLT2. To identify the 1,5-AG transporter, both human and mouse SGLT4 and SGLT5 were expressed in HEK293T cells and transport measurements were performed with radiolabelled compounds. We found that SGLT5 is a better carrier for 1,5-AG than for mannose, while the opposite is true for human SGLT4. Heterozygous variants in SGLT5, associated with a low level of blood 1,5-AG in humans cause a 50-100% reduction in 1,5-AG transport activity tested in model cell lines, indicating that SGLT5 is the predominant kidney 1,5-AG transporter. These and other findings led to the conclusion that (1) SGLT5 is the main renal transporter of 1,5-AG; (2) frequent heterozygous mutations (allelic frequency > 1%) in SGLT5 lower blood 1,5-AG, favourably influencing neutropenia in G6PC3 or G6PT deficiency; (3) the effect of SGLT2-inhibitors on blood 1,5-AG level is largely indirect; (4) specific SGLT5-inhibitors would be more efficient to treat these neutropenias than SGLT2-inhibitors.
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Affiliation(s)
- Jennifer Diederich
- Metabolic Research Group, de Duve Institute and UCLouvain, de Duve Institute, 75, Av. Hippocrate, 1200, Brussels, Belgium
| | - Pierre Mounkoro
- Metabolic Research Group, de Duve Institute and UCLouvain, de Duve Institute, 75, Av. Hippocrate, 1200, Brussels, Belgium
| | - Hernan A Tirado
- Metabolic Research Group, de Duve Institute and UCLouvain, de Duve Institute, 75, Av. Hippocrate, 1200, Brussels, Belgium
| | - Nathalie Chevalier
- Metabolic Research Group, de Duve Institute and UCLouvain, de Duve Institute, 75, Av. Hippocrate, 1200, Brussels, Belgium
| | - Emile Van Schaftingen
- Metabolic Research Group, de Duve Institute and UCLouvain, de Duve Institute, 75, Av. Hippocrate, 1200, Brussels, Belgium
| | - Maria Veiga-da-Cunha
- Metabolic Research Group, de Duve Institute and UCLouvain, de Duve Institute, 75, Av. Hippocrate, 1200, Brussels, Belgium.
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Murko S, Peschka M, Tsiakas K, Schulz-Jürgensen S, Herden U, Santer R. Liver transplantation in glycogen storage disease type Ib: The role of SGLT2 inhibitors. Mol Genet Metab Rep 2023; 35:100977. [PMID: 37275680 PMCID: PMC10233270 DOI: 10.1016/j.ymgmr.2023.100977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 04/27/2023] [Accepted: 04/27/2023] [Indexed: 06/07/2023] Open
Abstract
We report on liver transplantation in two patients with GSD Ib on treatment with empagliflozin. The use of this SGLT2 inhibitor resulted in a marked decrease of 1,5-anhydroglucitol which has an important role in the development of neutropenia in this condition. As intended, this caused a significant rise of neutrophil numbers. Liver transplantation alone did not produce the desired effect and our observation argues for continuing SGLT2 inhibitor treatment after transplantation.
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Affiliation(s)
- Simona Murko
- Department of Pediatrics, University Medical Center Eppendorf, Hamburg, Germany
| | - Manuela Peschka
- Department of Pediatrics, University Medical Center Eppendorf, Hamburg, Germany
| | | | | | - Uta Herden
- Department of Transplant Surgery, University Medical Center Eppendorf, Hamburg, Germany
| | - René Santer
- Department of Pediatrics, University Medical Center Eppendorf, Hamburg, Germany
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Gehlhaar A, Shouval D, Santiago EG, Ling G, McCourt B, Werner L, Yerushalmi B, Konnikova L. Immune dysregulation in Glycogen Storage Disease 1b - a CyTOF approach. Res Sq 2023:rs.3.rs-2598829. [PMID: 36865166 PMCID: PMC9980199 DOI: 10.21203/rs.3.rs-2598829/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Glycogen Storage Disease type 1b (GSD1b) is a rare disease manifesting as hypoglycemia, recurrent infections and neutropenia, resulting from deleterious mutations in the SLC37A4 gene encoding the glucose-6-phosphate transporter. The susceptibility to infections is thought to be attributed not only to the neutrophil defect, though extensive immunophenotyping characterization is currently missing. Here we apply a systems immunology approach utilizing Cytometry by Time Of Flight (CyTOF) to map the peripheral immune landscape of 6 GSD1b patients. When compared to control subjects, those with GSD1b had a significant reduction in anti-inflammatory macrophages, CD16+ macrophages, and Natural Killer cells. Additionally, there was a preference towards a central versus an effector memory phenotype in multiple T cell populations, which may suggest that these changes stem from an inability of activated immune cell populations to undergo the appropriate switch to glycolytic metabolism in the hypoglycemic conditions associated with GSD1b. Furthermore, we identified a global reduction of CD123, CD14, CCR4, CD24 and CD11b across several populations and a multi-cluster upregulation of CXCR3, hinting at a potential role of impaired immune cell trafficking in the context of GSD1b. Taken together, our data indicates that that the immune impairment observed in GSD1b patients extends far beyond neutropenia and encompasses innate and adaptive compartments, which may provide novel insights into the pathogenesis of this disorder.
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Boulanger C, Stephenne X, Diederich J, Mounkoro P, Chevalier N, Ferster A, Van Schaftingen E, Veiga‐da‐Cunha M. Successful use of empagliflozin to treat neutropenia in two G6PC3-deficient children: Impact of a mutation in SGLT5. J Inherit Metab Dis 2022; 45:759-768. [PMID: 35506446 PMCID: PMC9540799 DOI: 10.1002/jimd.12509] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 04/28/2022] [Accepted: 05/02/2022] [Indexed: 11/10/2022]
Abstract
Neutropenia and neutrophil dysfunction found in deficiencies in G6PC3 and in the glucose-6-phosphate transporter (G6PT/SLC37A4) are due to accumulation of 1,5-anhydroglucitol-6-phosphate (1,5-AG6P), an inhibitor of hexokinase made from 1,5-anhydroglucitol (1,5-AG), an abundant polyol present in blood. Lowering blood 1,5-AG with an SGLT2 inhibitor greatly improved neutrophil counts and function in G6PC3-deficient mice and in patients with G6PT-deficiency. We evaluate this treatment in two G6PC3-deficient children. While neutropenia was severe in one child (PT1), which was dependent on granulocyte cololony-stimulating factor (GCSF), it was significantly milder in the other one (PT2), which had low blood 1,5-AG levels and only required GCSF during severe infections. Treatment with the SGLT2-inhibitor empagliflozin decreased 1,5-AG in blood and 1,5-AG6P in neutrophils and improved (PT1) or normalized (PT2) neutrophil counts, allowing to stop GCSF. On empagliflozin, both children remained infection-free (>1 year - PT2; >2 years - PT1) and no side effects were reported. Remarkably, sequencing of SGLT5, the gene encoding the putative renal transporter for 1,5-AG, disclosed a rare heterozygous missense mutation in PT2, replacing the extremely conserved Arg401 by a histidine. The higher urinary clearance of 1,5-AG explains the more benign neutropenia and the outstanding response to empagliflozin treatment found in this child. Our data shows that SGLT2 inhibitors are an excellent alternative to treat the neutropenia present in G6PC3-deficiency.
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Affiliation(s)
- Cécile Boulanger
- Biologie HématologiqueCliniques Universitaires Saint‐Luc, UCLouvainBrusselsBelgium
| | - Xavier Stephenne
- Service de Gastro‐Entérologie et Hépatologie PédiatriqueCliniques Universitaires Saint‐Luc, UCLouvainBrusselsBelgium
| | - Jennifer Diederich
- Groupe de Recherches Metaboliquesde Duve Institute, UCLouvainBrusselsBelgium
| | - Pierre Mounkoro
- Groupe de Recherches Metaboliquesde Duve Institute, UCLouvainBrusselsBelgium
| | - Nathalie Chevalier
- Groupe de Recherches Metaboliquesde Duve Institute, UCLouvainBrusselsBelgium
| | - Alina Ferster
- Department of Hematology/OncologyHôpital Universitaire des Enfants Reine Fabiola, Université Libre de BruxellesBrusselsBelgium
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Eghbali M, Abiri M, Talebi S, Noroozi Z, Shakiba M, Rostami P, Alimadadi H, Najafi M, Yazarlou F, Rabbani A, Modarressi MH. Genotype-phenotype correlation and description of two novel mutations in Iranian patients with glycogen storage disease 1b ( GSD1b). Orphanet J Rare Dis 2020; 15:35. [PMID: 32005221 PMCID: PMC6995048 DOI: 10.1186/s13023-019-1266-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 12/02/2019] [Indexed: 11/10/2022] Open
Abstract
Background Glycogen storage disease (GSD) is a rare inborn error of the synthesis or degradation of glycogen metabolism. GSD1, the most common type of GSD, is categorized into GSD1a and GSD1b which caused by the deficiency of glucose-6-phosphatase (G6PC) and glucose-6-phosphate transporter (SLC37A4), respectively. The high rates of consanguineous marriages in Iran provide a desirable context to facilitate finding the homozygous pathogenic mutations. This study designates to evaluate the clinical and genetic characteristics of patients with GSD1b to assess the possible genotype-phenotype correlation. Results Autozygosity mapping was performed on nineteen GSD suspected families to suggest the causative loci. The mapping was done using two panels of short tandem repeat (STR) markers linked to the corresponding genes. The patients with autozygous haplotype block for the markers flanking the genes were selected for direct sequencing. Six patients showed autozygosity in the candidate markers for SLC37A4. Three causative variants were detected. The recurrent mutation of c.1042_1043delCT (p.Leu348Valfs*53) and a novel missense mutation of c.365G > A (p.G122E) in the homozygous state were identified in the SLC37A4. In silico analysis was performed to predict the pathogenicity of the variants. A novel whole SLC37A4 gene deletion using long-range PCR and sequencing was confirmed as well. Severe and moderate neutropenia was observed in patients with frameshift and missense variants, respectively. The sibling with the whole gene deletion has shown both severe neutropenia and leukopenia. Conclusions The results showed that the hematological findings may have an appropriate correlation with the genotype findings. However, for a definite genotype-phenotype correlation, specifically for the clinical and biochemical phenotype, further studies with larger sample sizes are needed.
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Affiliation(s)
- Maryam Eghbali
- Department of Medical Genetics, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Abiri
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Saeed Talebi
- Department of Medical Genetics and Molecular Biology, Faculty of Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Zahra Noroozi
- Department of Molecular Medicine, School of Advanced Technologies in Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Marjan Shakiba
- Department of Pediatric Endocrinology and Metabolism, Mofid Children's Hospital, Shahid Beheshti University of medical sciences, Tehran, Iran
| | - Parastoo Rostami
- Growth and Development Research Center, Department of Endocrinology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Hosein Alimadadi
- Department of Gastroenterology, Children's Medical Center, Tehran University of Medical Science, Tehran, Iran
| | - Mehri Najafi
- Department of Gastroenterology, Children's Medical Center, Tehran University of Medical Science, Tehran, Iran
| | - Fatemeh Yazarlou
- Department of Medical Genetics, Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Rabbani
- Growth and Development Research Center, Department of Endocrinology, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
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