1
|
Gonzalez-Resines S, Quinn PJ, Naftalin RJ, Domene C. Multiple Interactions of Glucose with the Extra-Membranous Loops of GLUT1 Aid Transport. J Chem Inf Model 2021; 61:3559-3570. [PMID: 34260246 DOI: 10.1021/acs.jcim.1c00310] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Molecular dynamics simulations amounting to ≈8 μs demonstrate that the glucose transporter GLUT1 undergoes structural fluctuations mediated by the fluidity of the lipid bilayer and the proximity to glucose. The fluctuations of GLUT1 increase as the glucose concentration is raised. These fluctuations are more pronounced when the lipid bilayer is in the fluid compared to the gel phase. Glucose interactions are confined to the extra-membranous residues when the lipid is in the gel phase but diffuses into the transmembrane regions in the fluid phase. Proximity of glucose to GLUT1 causes asynchronous expansions of key bottlenecks at the internal and external openings of the central pore. This is accomplished only by small conformational changes at the single residue level that lower the resistance to glucose movements, thereby permitting unsteered glucose and water movements along the entire length of the pore. When glucose is near salt bridges located at the external and internal openings of the central pore, the distance separating the polar amino acid residues guarding these apertures tends to increase in both fluid and gel phases. It is evident that the multiplicity of glucose interactions, obtained with high concentrations, amplifies the structural fluctuations in GLUT1. The findings that most of the salt bridges and the bottlenecks appear to be operated by glucose proximity suggest that the main triggers to activation of transport are located within the solvent accessible linker regions in the extramembranous zones.
Collapse
Affiliation(s)
| | - Peter J Quinn
- Department of Biochemistry, King's College London, London WC2R 2LS, U.K
| | - Richard J Naftalin
- BHF Centre of Research Excellence, School of Medicine and Life Sciences, King's College London, London WC2R 2LS, U.K
| | - Carmen Domene
- Departments of Chemistry, University of Bath, Bath BA2 7AX, U.K.,Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, U.K
| |
Collapse
|
2
|
Naftalin RJ. A critique of the alternating access transporter model of uniport glucose transport. BIOPHYSICS REPORTS 2018; 4:287-299. [PMID: 30596138 PMCID: PMC6276071 DOI: 10.1007/s41048-018-0076-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 07/20/2018] [Indexed: 12/16/2022] Open
Affiliation(s)
- Richard J Naftalin
- Physiology and Vascular Biology Group, King's College London Medical School, Waterloo Campus, London, SE1 9HN UK
| |
Collapse
|
3
|
Lee J, Yanckello LM, Ma D, Hoffman JD, Parikh I, Thalman S, Bauer B, Hartz AMS, Hyder F, Lin AL. Neuroimaging Biomarkers of mTOR Inhibition on Vascular and Metabolic Functions in Aging Brain and Alzheimer's Disease. Front Aging Neurosci 2018; 10:225. [PMID: 30140223 PMCID: PMC6094969 DOI: 10.3389/fnagi.2018.00225] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Accepted: 07/02/2018] [Indexed: 01/14/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) is a nutrient sensor of eukaryotic cells. Inhibition of mechanistic mTOR signaling can increase life and health span in various species via interventions that include rapamycin and caloric restriction (CR). In the central nervous system, mTOR inhibition demonstrates neuroprotective patterns in aging and Alzheimer's disease (AD) by preserving mitochondrial function and reducing amyloid beta retention. However, the effects of mTOR inhibition for in vivo brain physiology remain largely unknown. Here, we review recent findings of in vivo metabolic and vascular measures using non-invasive, multimodal neuroimaging methods in rodent models for brain aging and AD. Specifically, we focus on pharmacological treatment (e.g., rapamycin) for restoring brain functions in animals modeling human AD; nutritional interventions (e.g., CR and ketogenic diet) for enhancing brain vascular and metabolic functions in rodents at young age (5-6 months of age) and preserving those functions in aging (18-20 months of age). Various magnetic resonance (MR) methods [i.e., imaging (MRI), angiography (MRA), and spectroscopy (MRS)], confocal microscopic imaging, and positron emission tomography (PET) provided in vivo metabolic and vascular measures. We also discuss the translational potential of mTOR interventions. Since PET and various MR neuroimaging methods, as well as the different interventions (e.g., rapamycin, CR, and ketogenic diet) are also available for humans, these findings may have tremendous implications in future clinical trials of neurological disorders in aging populations.
Collapse
Affiliation(s)
- Jennifer Lee
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Lucille M. Yanckello
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Pharmacology and Nutritional Science, University of Kentucky, Lexington, KY, United States
| | - David Ma
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Jared D. Hoffman
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Pharmacology and Nutritional Science, University of Kentucky, Lexington, KY, United States
| | - Ishita Parikh
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
| | - Scott Thalman
- F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY, United States
| | - Bjoern Bauer
- Department of Pharmaceutical Sciences, University of Kentucky, Lexington, KY, United States
| | - Anika M. S. Hartz
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Pharmacology and Nutritional Science, University of Kentucky, Lexington, KY, United States
| | - Fahmeed Hyder
- Departments of Radiology and Biomedical Engineering, Magnetic Resonance Research Center, Yale University, New Haven, CT, United States
| | - Ai-Ling Lin
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, United States
- Department of Pharmacology and Nutritional Science, University of Kentucky, Lexington, KY, United States
- F. Joseph Halcomb III, M.D. Department of Biomedical Engineering, University of Kentucky, Lexington, KY, United States
| |
Collapse
|
4
|
Abstract
OPINION STATEMENT In the absence of a culprit epileptogenic lesion, pharmacoresistant seizures should prompt the physician to consider potentially treatable metabolic epilepsies, especially in the presence of developmental delays. Even though the anti-seizure treatment of the epilepsies remains symptomatic and usually tailored to an electroclinical phenotype rather than to an underlying etiology, a thorough metabolic workup might reveal a disease with an etiology-specific treatment. Early diagnosis is essential in the case of treatable metabolic epilepsies allowing timely intervention. Despite the advances in genetic testing, biochemical testing including cerebrospinal fluid studies are still needed to expedite the diagnostic workup and potential therapeutic trials. The diagnostician should have a high index of suspicion despite potential clinical digressions from seminal publications describing the initial cases, as these index patients may represent the most severe form of the condition rather than its most common presenting form. The often gratifying developmental outcome and seizure control with early treatment calls for a prompt diagnostic consideration of treatable metabolic diseases; even though relatively rare or potentially only seemingly so.
Collapse
|
5
|
Nakamura S, Osaka H, Muramatsu S, Aoki S, Jimbo EF, Yamagata T. Mutational and functional analysis of Glucose transporter I deficiency syndrome. Mol Genet Metab 2015; 116:157-62. [PMID: 26304067 DOI: 10.1016/j.ymgme.2015.08.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Revised: 08/09/2015] [Accepted: 08/09/2015] [Indexed: 01/11/2023]
Abstract
OBJECTIVE We investigated a correlation between a mutation in the SLC2A1 gene and functional disorders in Glucose transporter I deficiency syndrome (GLUT1DS). METHODS We performed direct sequence analysis of SLC2A1 in a severe GLUT1DS patient and identified a novel frame shift mutation, c.906_907insG, p.V303fs. We created a plasmid vector carrying the c.906_907insG mutation, as well as A405D or R333W in the SLC2A1, which are found in patients with mild and moderate GLUT1DS severity, respectively. We transiently expressed these mutants and wild type SLC2A1 plasmids in a human embryonic kidney cell line (HEK293), and performed immunoblotting, immunofluorescence, and enzymatic photometric 2-deoxyglucose (2DG) uptake assays. RESULTS GLUT1 was not detected after transient expression of the SLC2A1 plasmid carrying c.906_907insG by either immunoblotting or immunofluorescence. The degree of glucose transport reduction as determined by enzymatic photometric 2DG assay uptake correlated with disease severity. CONCLUSIONS Enzymatic photometric 2DG uptake study appears to be a suitable functional assay to predict the effect of SLC2A1 mutations on GLUT1 transport.
Collapse
Affiliation(s)
- Sachie Nakamura
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan
| | - Hitoshi Osaka
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan.
| | - Shinichi Muramatsu
- Division of Neurology, Jichi Medical University, Tochigi, Japan; Center for Gene and Cell Therapy, The Institute of Medical Science, The University of Tokyo, Japan
| | - Shiho Aoki
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan
| | - Eriko F Jimbo
- Department of Pediatrics, Jichi Medical University, Tochigi, Japan
| | | |
Collapse
|
6
|
From splitting GLUT1 deficiency syndromes to overlapping phenotypes. Eur J Med Genet 2015; 58:443-54. [PMID: 26193382 DOI: 10.1016/j.ejmg.2015.06.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Accepted: 06/18/2015] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a rare genetic disorder due to mutations or deletions in SLC2A1, resulting in impaired glucose uptake through the blood brain barrier. The classic phenotype includes pharmacoresistant epilepsy, intellectual deficiency, microcephaly and complex movement disorders, with hypoglycorrhachia, but milder phenotypes have been described (carbohydrate-responsive phenotype, dystonia and ataxia without epilepsy, paroxysmal exertion-induced dystonia). The aim of our study was to provide a comprehensive overview of GLUT1DS in a French cohort. METHODS 265 patients were referred to the French national laboratory for molecular screening between July 2006 and January 2012. Mutations in SLC2A1 were detected in 58 patients, with detailed clinical data available in 24, including clinical features with a focus on their epileptic pattern and electroencephalographic findings, biochemical findings and neuroimaging findings. RESULTS 53 point mutations and 5 deletions in SLC2A1 were identified. Most patients (87.5%) exhibited classic phenotype with intellectual deficiency (41.7%), epilepsy (75%) or movement disorder (29%) as initial symptoms at a medium age of 7.5 months, but diagnostic was delayed in most cases (median age at diagnostic 8 years 5 months). Sensitivity to fasting or exertion in combination with those 3 main symptoms were the main differences between mutated and negative patients (p < 0.001). Patients with myoclonic seizures (52%) evolved with more severe intellectual deficiency and movement disorders compared with those with Early Onset Absence Epilepsy (38%). Three patients evolved from a classic phenotype during early childhood to a movement disorder predominant phenotype at a late childhood/adulthood. CONCLUSIONS Our data confirm that the classic phenotype is the most frequent in GLUT1DS. Myoclonic seizures are a distinctive feature of severe forms. However a great variability among patients and overlapping through life from milder classic phenotype to paroxysmal-prominent- movement-disorder phenotype are possible, thus making it difficult to identify definite genotype-phenotype correlations.
Collapse
|
7
|
Cunningham P, Naftalin RJ. Implications of aberrant temperature-sensitive glucose transport via the glucose transporter deficiency mutant (GLUT1DS) T295M for the alternate-access and fixed-site transport models. J Membr Biol 2013; 246:495-511. [PMID: 23740044 DOI: 10.1007/s00232-013-9564-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 05/15/2013] [Indexed: 12/27/2022]
Abstract
In silico glucose docking to the transporter GLUT1 templated to the crystal structure of Escherichia coli XylE, a bacterial homolog of GLUT1-4 (4GBZ.pdb), reveals multiple docking sites. One site in the external vestibule in the exofacial linker between TM7 and -8 is adjacent to a missense T295M and a 4-mer insertion mutation. Glucose docking to the adjacent site is occluded in these mutants. These mutants cause an atypical form of glucose transport deficiency syndrome (GLUT1DS), where transport into the brain is deficient, although unusually transport into erythrocytes at 4 °C appears normal. A model in which glucose traverses the transporter via a network of saturable fixed sites simulates the temperature sensitivity of normal and mutant glucose influx and the mutation-dependent alterations of influx and efflux asymmetry when expressed in Xenopus oocytes at 37 °C. The explanation for the temperature sensitivity is that at 4 °C glucose influx between the external and internal vestibules is slow and causes glucose to accumulate in the external vestibule. This retards net glucose uptake from the external solution via two parallel sites into the external vestibule, consequently masking any transport defect at either one of these sites. At 37 °C glucose transit between the external and internal vestibules is rapid, with no significant glucose buildup in the external vestibule, and thereby unmasks any transport defect at one of the parallel input sites. Monitoring glucose transport in patients' erythrocytes at higher temperatures may improve the diagnostic accuracy of the functional test of GLUT1DS.
Collapse
Affiliation(s)
- Philip Cunningham
- Bioinformatics Division, School of Medicine, King's College London, Franklin-Wilkins Building, Waterloo Campus, London SE1 9HN, UK
| | | |
Collapse
|
8
|
Ramm-Pettersen A, Nakken KO, Skogseid IM, Randby H, Skei EB, Bindoff LA, Selmer KK. Good outcome in patients with early dietary treatment of GLUT-1 deficiency syndrome: results from a retrospective Norwegian study. Dev Med Child Neurol 2013; 55:440-7. [PMID: 23448551 DOI: 10.1111/dmcn.12096] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/23/2012] [Indexed: 01/02/2023]
Abstract
AIM The aim of this study was to characterize patients diagnosed with glucose transporter protein-1 deficiency syndrome (GLUT-1 DS) clinically and genetically, and to evaluate the effect of treatment with the classic ketogenic or modified Atkins diet. METHOD We retrospectively studied medical records of 10 patients diagnosed with GLUT-1 DS. Four females and six males with a median age of 15 years were included. RESULTS The study illustrates the genetic and clinical heterogeneity of GLUT-1 DS. Analysis of the SLC2A1 gene disclosed a variety of mutation types. The time between onset of symptoms and diagnosis was more than 11 years on average. The outcome in those with early diagnosis and intervention was surprisingly good. All but one patient with the classic phenotype became seizure free after treatment with the classic ketogenic or modified Atkins diet. Acetazolamide was effective in one patient with paroxysmal exercise-induced dyskinesia. A point prevalence of GLUT-1 DS in Norway was estimated as 2.6 per 1,000,000 inhabitants. INTERPRETATION Although the long-term prognosis in patients with GLUT-1 DS partly depends on the underlying genetics, our study supports the assumption that early initiation of treatment with a ketogenic diet may positively affect the outcome.
Collapse
|
9
|
First report of glucose transporter 1 deficiency syndrome in Korea with a novel splice site mutation. Gene 2012; 506:380-2. [DOI: 10.1016/j.gene.2012.06.095] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Revised: 06/19/2012] [Accepted: 06/25/2012] [Indexed: 11/19/2022]
|
10
|
Pong AW, Geary BR, Engelstad KM, Natarajan A, Yang H, De Vivo DC. Glucose transporter type I deficiency syndrome: Epilepsy phenotypes and outcomes. Epilepsia 2012; 53:1503-10. [DOI: 10.1111/j.1528-1167.2012.03592.x] [Citation(s) in RCA: 99] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
11
|
Verrotti A, D'Egidio C, Agostinelli S, Gobbi G. Glut1 deficiency: when to suspect and how to diagnose? Eur J Paediatr Neurol 2012; 16:3-9. [PMID: 21962875 DOI: 10.1016/j.ejpn.2011.09.005] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2011] [Accepted: 09/18/2011] [Indexed: 11/19/2022]
Abstract
Impaired glucose transport across the blood-brain barrier results in GLUT1 deficiency syndrome (GLUT1-DS), characterized by infantile seizures, developmental delay, acquired microcephaly, spasticity, ataxia, and hypoglycorrhachia. A part from this classic phenotype, clinical conditions associated with a deficiency of GLUT1 are highly variable and several atypical variants have been described; in particular, patients with movement disorders, but without seizures, with paroxysmal exertion-induced dyskinesia, have been reported. Most patients carry heterozygous de novo mutations in the GLUT1-gene but autosomal dominant and recessive transmission has been identified. Diagnosis is based on low cerebrospinal fluid glucose, in the absence of hypoglycemia, and it is confirmed by molecular analysis of the GLUT1-gene and by glucose uptake studies and immunoreactivity in human erythrocytes. Treatment with a ketogenic diet results in marked improvement of seizures and movement disorders. This review summarizes recent advances in understanding of GLUT1-DS and highlights the diagnostic and therapeutic approach to GLUT1-DS.
Collapse
Affiliation(s)
- A Verrotti
- Department of Paediatrics, University of Chieti, Ospedale policlinico SS. Annunziata, Via dei Vestini 5, 66100 Chieti, Italy.
| | | | | | | |
Collapse
|
12
|
Fujii T, Morimoto M, Yoshioka H, Ho YY, Law PPY, Wang D, De Vivo DC. T295M-associated Glut1 deficiency syndrome with normal erythrocyte 3-OMG uptake. Brain Dev 2011; 33:316-20. [PMID: 20630673 DOI: 10.1016/j.braindev.2010.06.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/24/2009] [Revised: 06/04/2010] [Accepted: 06/17/2010] [Indexed: 12/01/2022]
Abstract
PURPOSE Glucose transporter type 1 (Glut1) is expressed in vascular endothelial cells comprising blood-brain barrier. Glut1 deficiency syndrome is characterized by low cerebrospinal fluid (CSF) concentration of glucose with normoglycemia, infantile seizure, acquired microcephaly, developmental delay and ataxia. As Glut1 is also expressed in erythrocytes, the diagnosis is confirmed by a decreased uptake of 3-O-methylglucose (3-OMG) into erythrocytes. However, patients with T295M mutation in the Glut1 gene show normal 3-OMG uptake. An in vitro study has proved that the T295M affects efflux rather than influx of glucose, explaining the discrepancy. However, the normal 3-OMG uptake in erythrocytes still indicates a possibility that the phenotype associated with this particular mutation may be milder. We compared the phenotype of three T295M-associated patients with that of other Glut1-deficient patients. PATIENTS AND METHODS Two patients are from our clinic and one is a patient reported elsewhere. The phenotype and biochemical data of patients with mutations other than T295M were obtained from a review and our previous report. RESULTS Despite the normal 3-OMG uptake into erythrocytes, all patients with T295M showed decreased glucose levels in CSF (33, 31 and 38mg/dl, respectively). The levels were comparable to those in patients with mutations other than T295M (31±4.3mg/dl (n=45)). All patients had convulsion, ataxia, speech delay, microcephaly and spasticity. CONCLUSION Despite the normal 3-OMG uptake in erythrocytes, phenotype of T295M-associated Glut1 deficiency was not significantly different from that of patients with a deficient 3-OMG uptake, indicating that T295M affects the glucose transport at the blood-brain barrier as much as other mutations.
Collapse
Affiliation(s)
- Tatsuya Fujii
- Department of Pediatrics, Shiga Medical Center for Children, 5-7-30 Moriyama, Shiga, Japan.
| | | | | | | | | | | | | |
Collapse
|
13
|
Roubergue A, Apartis E, Mesnage V, Doummar D, Trocello JM, Roze E, Taieb G, De Villemeur TB, Vuillaumier-Barrot S, Vidailhet M, Levy R. Dystonic tremor caused by mutation of the glucose transporter gene GLUT1. J Inherit Metab Dis 2011; 34:483-8. [PMID: 21229316 DOI: 10.1007/s10545-010-9264-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2010] [Revised: 12/07/2010] [Accepted: 12/09/2010] [Indexed: 11/30/2022]
Abstract
Glucose transporter 1 deficiency syndrome (GLUT1-DS) is due to heterozygous mutation of the glucose transporter type 1 gene (GLUT1/SLC2A1). GLUT1-DS is characterized by movement disorders, including paroxysmal exercise-induced dystonia (PED), as well as seizures, mental retardation and hypoglycorrhachia. Tremor was recently shown to be part of the phenotype, but its clinical and electrophysiological features have not yet been described in detail, and GLUT1 tremor reports are rare. We describe two patients, a young woman and her mother, who were referred to us for tremor. We also systematically review published cases of GLUT1-DS with tremor (14 cases, including ours), focusing on clinical features. In most cases (10/14), the tremor, which involved the limbs and voice, fulfilled clinical criteria for dystonic tremor (DT), occurring in body areas affected by dystonia. Tremor was the only permanent symptom in 2 cases. Recordings, reported here for the first time, showed an irregular 6- to 8.5-Hz tremor compatible with DT in our two patients. These findings show that tremor, and particularly DT, may be a presenting symptom of GLUT1-DS. Patients who present with dystonic tremor, with or without mental retardation, seizures, movement disorders and/or a family history, should therefore be screened for GLUT1-DS.
Collapse
Affiliation(s)
- Anne Roubergue
- AP-HP, Service de Neuropédiatrie, Hôpital Trousseau, Paris, France.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Fung ELW, Ho YY, Hui J, Wong JH, Ng TB, Fong NYF, Klepper J, Tsui KWS. First report of GLUT1 deficiency syndrome in Chinese patients with novel and hot spot mutations in SLC2A1 gene. Brain Dev 2011; 33:170-3. [PMID: 20417043 DOI: 10.1016/j.braindev.2010.03.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2010] [Revised: 03/06/2010] [Accepted: 03/23/2010] [Indexed: 11/18/2022]
Abstract
Glucose transporter type 1 deficiency syndrome (GLUT1DS) is increasingly recognized as a cause of various neurological disorders but a high index of suspicion is important to make the diagnosis. We report two Chinese patients with GLUT1DS, one of which had a novel mutation in the SLC2A1 gene.
Collapse
Affiliation(s)
- Eva Lai-wah Fung
- Department of Paediatrics, The Chinese University of Hong Kong, China.
| | | | | | | | | | | | | | | |
Collapse
|
15
|
Glucose transporter type 1 deficiency: ketogenic diet in three patients with atypical phenotype. Brain Dev 2010; 32:404-8. [PMID: 19515520 DOI: 10.1016/j.braindev.2009.04.013] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Revised: 04/14/2009] [Accepted: 04/24/2009] [Indexed: 01/01/2023]
Abstract
Glucose transporter type I deficiency syndrome (GLUT-1 DS) is an inborn error of glucose transport characterized by seizures, developmental delay, spasticity, acquired microcephaly and ataxia. Diagnosis is based on the finding of low cerebrospinal fluid glucose, in the absence of hypoglycemia, and identification of GLUT-1 gene mutation on chromosome 1. The classic phenotype is a severe form of early onset epileptic encephalopathy, but patient with different clinical presentation have been reported expanding the clinical spectrum. In particular, many patients show a prominent movement disorder other than epilepsy. It is known that this disease represents a treatable condition and ketogenic diet (KD) is the elective treatment in GLUT-1 DS patients. We report on KD in three unrelated Italian GLUT-1 DS female patients, diagnosed in early adulthood, all presenting with an atypical phenotype. Preliminary results seem to demonstrate efficacy of KD on paroxysmal movement disorder while positive effect on cognitive impairment result less evident.
Collapse
|
16
|
Schneider SA, Paisan-Ruiz C, Garcia-Gorostiaga I, Quinn NP, Weber YG, Lerche H, Hardy J, Bhatia KP. GLUT1 gene mutations cause sporadic paroxysmal exercise-induced dyskinesias. Mov Disord 2010; 24:1684-8. [PMID: 19630075 DOI: 10.1002/mds.22507] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Paroxysmal exercise-induced dyskinesias (PED) are involuntary intermittent movements triggered by prolonged physical exertion. Autosomal dominant inheritance may occur. Recently, mutations in the glucose transporter 1 (GLUT1) gene (chr. 1p35-p31.3) have been identified as a cause in some patients with autosomal dominant PED. Mutations in this gene have previously been associated with the GLUT1 deficiency syndrome. We performed mutational analysis in 10 patients with apparently sporadic PED. We identified two novel GLUT1 mutations, at least one likely to be de-novo, in two of our patients. Onset was in early childhood. One of our patients had a predating history of childhood absence epilepsy and a current history of hemiplegic migraine as well as a family history of migraine. The other patient had no other symptoms apart from PED. Brain MRI showed cerebellar atrophy in one case. Mutations in GLUT1 are one cause of apparently sporadic PED. The detection of this has important implications for treatment as ketogenic diet has been reported to be beneficial.
Collapse
Affiliation(s)
- Susanne A Schneider
- Sobell Department of Motor Neuroscience and Movement Disorders, Institute of Neurology, UCL, Queen Square, London, United Kingdom
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Wang D, Yang H, Shi L, Ma L, Fujii T, Engelstad K, Pascual JM, De Vivo DC. Functional studies of the T295M mutation causing Glut1 deficiency: glucose efflux preferentially affected by T295M. Pediatr Res 2008; 64:538-43. [PMID: 18614966 DOI: 10.1203/pdr.0b013e318184d2b5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Glucose transporter type 1 (Glut1) deficiency syndrome (Glut1 DS, OMIM: #606777) is characterized by infantile seizures, acquired microcephaly, developmental delay, hypoglycorrhachia (CSF glucose <40 mg/dL), and decreased erythrocyte glucose uptake (56.1 +/- 17% of control). Previously, we reported two patients with a mild Glut1 deficiency phenotype associated with a heterozygous GLUT1 T295M mutation and normal erythrocyte glucose uptake. We assessed the pathogenicity of T295M in the Xenopus laevis oocyte expression system. Under zero-trans influx conditions, the T295M Vmax (590 pmol/min/oocyte) was 79% of the WT value and the Km (14.3 mM) was increased compared with WT (9.6 mM). Under zero-trans efflux conditions, both the Vmax (1216 pmol/min/oocyte) and Km (8.8 mM) in T295M mutant Glut1 were markedly decreased in comparison to the WT values (7443 pmol/min/oocyte and 90.8 mM). Western blot analysis and confocal studies confirmed incorporation of the T295M mutant protein into the plasma membrane. The side chain of M295 is predicted to block the extracellular "gate" for glucose efflux in our Glut-1 molecular model. We conclude that the T295M mutation specifically alters Glut1 conformation and asymmetrically affects glucose flux across the cell by perturbing efflux more than influx. These findings explain the seemingly paradoxical findings of Glut1 DS with hypoglycorrhachia and "normal" erythrocyte glucose uptake.
Collapse
Affiliation(s)
- Dong Wang
- Department of Neurology, Columbia University, New York, New York 10032, USA
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Disturbance of cellular glucose transport by two prevalently used fluoroquinolone antibiotics ciprofloxacin and levofloxacin involves glucose transporter type 1. Toxicol Lett 2008; 184:81-4. [PMID: 19022360 DOI: 10.1016/j.toxlet.2008.10.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2008] [Revised: 10/20/2008] [Accepted: 10/21/2008] [Indexed: 11/21/2022]
Abstract
Dysglycemia and central nervous system (CNS) complications are the known adverse effects of fluoroquinolone antibiotics. Ciprofloxacin and levofloxacin are among the most prescribed antibiotics. In this study we demonstrate that ciprofloxacin and levofloxacin disturb glucose transport into HepG2 cells and such inhibition is associated with inhibited glucose transporter type 1 (GLUT1) function. When exposed to ciprofloxacin or levofloxacin at maximum plasma concentrations (C(max)) and 5x of C(max) concentrations, GLUT1 mRNA expression, cell surface GLUT1 protein expression and glucose uptake were significantly reduced. These findings imply that disturbed cellular glucose transport and GLUT1 function may underlie the dysglycemic and CNS effects of ciprofloxacin and levofloxacin.
Collapse
|
19
|
Ticus I, Cano A, Villeneuve N, Milh M, Mancini J, Chabrol B. Le syndrome de déficit en GLUT-1 ou maladie de De Vivo : à propos d’un cas. Arch Pediatr 2008; 15:1296-9. [DOI: 10.1016/j.arcped.2008.04.024] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 01/22/2008] [Accepted: 04/20/2008] [Indexed: 11/28/2022]
|
20
|
Takahashi S, Ohinata J, Suzuki N, Amamiya S, Kajihama A, Sugai R, Araki A, Fujieda K, Tanaka H. Molecular analysis and anticonvulsant therapy in two patients with glucose transporter 1 deficiency syndrome: A successful use of zonisamide for controlling the seizures. Epilepsy Res 2008; 80:18-22. [DOI: 10.1016/j.eplepsyres.2008.03.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2007] [Revised: 12/26/2007] [Accepted: 03/05/2008] [Indexed: 10/22/2022]
|
21
|
[Glucose transporter type 1 (GLUT-1) deficiency]. Rev Neurol (Paris) 2008; 164:896-901. [PMID: 18808765 DOI: 10.1016/j.neurol.2008.02.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 01/10/2008] [Accepted: 02/08/2008] [Indexed: 11/24/2022]
Abstract
Impaired glucose transport across the blood brain barrier results in glucose transporter type 1 (GLUT-1) deficiency syndrome, first described in 1991. It is characterized by infantile seizures refractory to anticonvulsive treatments, microcephaly, delays in mental and motor development, spasticity, ataxia, dysarthria and other paroxysmal neurologic phenomena, often occurring prior to meals. Affected infants are normal at birth following an uneventful pregnancy and delivery. Seizures usually begin between the age of one and four months and can be preceded by apneic episodes or abnormal eyes movements. Patients with atypical presentations such as mental retardation and intermittent ataxia without seizures, or movement disorders characterized by choreoathetosis and dystonia, have also been described. Glucose is the principal fuel source for the brain and GLUT-1 is the only vehicle by which glucose enters the brain. In case of GLUT-1 deficiency, the risk of clinical manifestations is increased in infancy and childhood, when the brain glucose demand is maximal. The hallmark of the disease is a low glucose concentration in the cerebrospinal fluid in a presence of normoglycemia (cerebrospinal fluid/blood glucose ratio less than 0.4). The GLUT-1 defect can be confirmed by molecular analysis of the SCL2A1 gene or in erythrocytes by glucose uptake studies and GLUT-1 immunoreactivity. Several heterozygous mutations, with a majority of de novo mutations, resulting in GLUT-1 haploinsufficiency, have been described. Cases with an autosomal dominant transmission have been established and adults can exhibit symptoms of this deficiency. Ketogenic diet is an effective treatment of epileptic manifestations as ketone bodies serve as an alternative fuel for the developing brain. However, this diet is not effective on cognitive impairment and other treatments are being evaluated. The physiopathology of this disorder is partially unclear and its understanding could explain the clinical heterogeneity of GLUT-1 deficiency patients and lead to new treatments. This probably under-diagnosed deficiency should be suspected in children with unexplained neurological disorders including epilepsy, mental retardation and movement disorders and confirmed by a lumbar puncture and the direct sequencing of GLUT-1.
Collapse
|
22
|
Effects of ketogenic diet on epileptiform activity in children with therapy resistant epilepsy. Epilepsy Res 2007; 77:134-40. [DOI: 10.1016/j.eplepsyres.2007.09.008] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2007] [Revised: 08/13/2007] [Accepted: 09/23/2007] [Indexed: 11/17/2022]
|
23
|
Abstract
GLUT1 deficiency syndrome (GLUT1DS, OMIM 606777) is a treatable epileptic encephalopathy resulting from impaired glucose transport into the brain. The essential biochemical finding is a low glucose concentration in the cerebrospinal fluid (CSF; hypoglycorrhachia; mean 1.7 [SD 0.3mmol/L]) in the setting of normoglycaemia. CSF lactate is normal. Patients present with an early-onset epilepsy resistant to anticonvulsants, developmental delay, and a complex movement disorder. Hypotonic, ataxic, and dystonic features are most prominent. Speech is often severely affected. Some patients develop spasticity and secondary microcephaly. The phenotype is highly variable ranging from severe impairment to children without seizures. Electroencephalography (EEG) may show 2.5-4Hz spike-waves improving on food intake. Neuroimaging is uninformative. Most patients carry heterozygous de novo mutations in the GLUT1 gene (OMIM 138140, gene map locus 1p35-31.3). Autosomal dominant transmission and several mutational hot spots have been identified, but phenotype-genotype correlations are not yet apparent. Homozygous GLUT1 mutations presumably are lethal. The ketogenic diet is the treatment of choice as it provides an alternative fuel to the brain. It should be introduced early and maintained into puberty. Seizures are effectively controlled with the onset of ketosis, but might recur and require comedication. The effect on neurodevelopment appears less impressive. The increasing number of patients, molecular and biochemical analysis, recent research into ketogenic diet mechanisms, and the development of animal models for GLUT1DS have brought substantial insights in disease manifestations and mechanisms. This review summarizes data on 84 published cases and highlights recent advances in understanding this entity.
Collapse
|
24
|
Wong HY, Law PY, Ho YY. Disease-associated Glut1 single amino acid substitute mutations S66F, R126C, and T295M constitute Glut1-deficiency states in vitro. Mol Genet Metab 2007; 90:193-8. [PMID: 17052934 DOI: 10.1016/j.ymgme.2006.09.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/05/2006] [Accepted: 09/05/2006] [Indexed: 11/17/2022]
Abstract
Glucose transporter type 1 deficiency syndrome (Glut1DS) is the result of autosomal-dominant loss-of-function mutation of the glucose transporter type 1 gene (GLUT1) leading to brain energy failure and epileptic encephalopathy. In this study, the protein products of the Glut1DS-associated GLUT1 missense mutations, S66F, R126C, and T295M, were characterized using the Glut1-green fluorescent protein (GFP) fusion expressed in CHO cells. Glut1-GFP expression was confirmed by Western blot and confocal microscopy. The applicability of this Glut1-GFP expression model in reporting Glut1 functional deficits was validated by re-confirming the glucose transport defects of the previously reported pathogenic mutations R126H, R126L, and R333W. While S66F, R126C, and T295M mutants were expressed and targeted to the cell membrane, these Glut1 mutants have significantly diminished membrane association and glucose transport activity (p<0.05) relative to the wild-type Glut1 protein. Consistent with the reduced Glut1 membrane association, glucose transport kinetics studies showed that S66F, R126C, and T295M mutants have significantly reduced (p<0.05) Vmax but not Km. Thus, Glut1 single amino acid substitute mutants S66F, R126C, and T295M impair glucose transport function and constitute Glut1-deficiency states in vitro. These results support the pathogenicity of Glut1 S66F, R126C, and T295M in vivo.
Collapse
Affiliation(s)
- H Y Wong
- Molecular Biotechnology Program, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | | | | |
Collapse
|