OBJECTIVE: To analyze the clinical phenotype and variant of SLC2A1 gene in a Chinese pedigree affected with glucose transporter type 1 deficiency syndrome (GLUT1-DS). METHODS: Clinical data of a child who was treated due to delayed motor and language development and his family members were collected. DNA was extracted from peripheral blood samples and subjected to high-throughput medical exome sequencing. Candidate variant was verified by Sanger sequencing of his parents and sister. The genotype-phenotype correlation was explored. RESULTS: The child, his mother and sister had common manifestations such as delayed mental and motor development, poor exercise tolerance, easy fatigue and paroxysmal dystonia, but the difference was that the child and his mother had microcephaly and seizures, while his sister did not. A heterozygous missense SLC2A1 c.191T>C (p.L64P) variant was identified in all affected members, which was unreported previously. CONCLUSION The missense SLC2A1 c.191T>C (p.L64P) variant probably underlay the disease in the proband and his mother and sister. Variability of the clinical phenotypes has reflected the genetic and phenotypic diversity of GLUT1-DS. Detection of the novel variant has enriched the spectrum of GLUT1-DS mutations.
Carbohydrate Metabolism, Inborn Errors ; China ; Glucose Transporter Type 1/genetics* ; Humans ; Monosaccharide Transport Proteins/deficiency* ; Mutation ; Pedigree ; Phenotype

OBJECTIVETo investigate the clinical features, diagnosis and treatment of glucose transporter 1 deficiency syndrome (GLUT1-DS), as well as the diagnostic value of movement disorders.

METHODSThe clinical data of four children with GLUT1-DS were collected, and their clinical features, treatment, and follow-up results were analyzed.

RESULTSThere were two boys and two girls, with an age of onset of 2-15 months. Clinical manifestations included movement disorders, seizures, and developmental retardation. Seizures were the cause of the first consultation in all cases. The four children all had persistent ataxia, dystonia, and dysarthria; two had persistent tremor, two had paroxysmal limb paralysis, and two had eye movement disorders. Paroxysmal symptoms tended to occur in fatigue state. All four children had reductions in the level of cerebrospinal fluid glucose and its ratio to blood glucose, as well as SLC2A1 gene mutations. The four children were given a ketogenic diet, at a ketogenic ratio of 2:1 to 3:1, and achieved complete remission of paroxysmal symptoms within 5 weeks.

CONCLUSIONSGLUT1-DS should be considered for epileptic children with mental retardation and motor developmental delay complicated by various types of movement disorders. The ketogenic diet is effective at a ketogenic ratio of 2:1 to 3:1 for the treatment of GLUT1-DS.

Carbohydrate Metabolism, Inborn Errors ; diagnosis ; genetics ; therapy ; Child ; Child, Preschool ; Female ; Humans ; Male ; Monosaccharide Transport Proteins ; deficiency ; genetics ; Movement Disorders ; diagnosis ; genetics ; therapy

OBJECTIVETo analyze the clinical and SLC2A1 gene mutation characteristics of glucose transporter type 1 deficiency syndrome.

METHODThe detailed clinical manifestations of six cases were recorded. The laboratory tests including EEG, MRI, blood chemistry, and lumbar puncture were performed. SLC2A1 gene mutations were analyzed by PCR, DNA sequencing and multiplex ligation-dependent probe amplification (MLPA).

RESULTPatient 1, 2 and 3 had classical clinical symptoms including infantile onset seizures, development delay. Patient 4, 5 and 6 had non-classical clinical symptoms including paroxysmal behavior disturbance, weakness, ataxia, lethargy, especially after fasting or exercise, without severe seizures. The plasma glucose levels were normal. The CSF glucose levels decreased in all the six cases, ranged from 1.10 mmol/L to 2.45 mmol/L, the mean level was 1.68 mmol/L. The CSF glucose/plasma glucose ratios decreased, ranged from 0.16 to 0.51, the mean ratio was 0.34. Four patients had normal EEG. Two patients had focal and diffuse epileptiform discharge, and one of them also had paroxysmal occipital or generalized high-amplitude slow waves during awake and sleep time. MRI abnormalities were found in three patients, patient 1 with mild brain atrophy, patient 3 with bilateral ventricle plump, and patient 4 with high signals in T2 in the frontal and occipital white matter, interpreted as hypomyelination. SLC2A1 gene mutations were found in six cases. Patient 1 has large scale deletion in exon 2. In patient 2 to 6, the mutations were c.741 G>A (E247K), 599delA, 761delA, c.1148 C>A (P383H), c.1198 C>T (R400C) respectively. Two patients were treated with ketogenic diet. The seizures disappeared and development became normal. Three patients responded to frequent meals with snacks. One patient refused any treatments, the symptoms continued to exist.

CONCLUSIONThe clinical manifestations of glucose transporter type 1 deficiency syndrome are varied. The common symptoms included infantile onset seizures and various paroxysmal events. These neurologic symptoms generally fluctuated and were influenced by factors such as fasting or fatigue. This feature could be a very important clue for the diagnosis of GLUT1-DS. Lumbar puncture is recommended in patients with episodic CNS symptoms especially after fasting. GLUT1-DS is a treatable neurometabolic disorder, early diagnosis and treatment may improve the prognosis of the patients.

Biomarkers ; analysis ; Brain ; diagnostic imaging ; pathology ; Carbohydrate Metabolism, Inborn Errors ; diagnosis ; genetics ; therapy ; Child ; Child, Preschool ; DNA Mutational Analysis ; Diet, Ketogenic ; Electroencephalography ; Epilepsy ; diagnosis ; genetics ; therapy ; Female ; Follow-Up Studies ; Glucose Transporter Type 1 ; genetics ; Humans ; Infant ; Magnetic Resonance Imaging ; Male ; Monosaccharide Transport Proteins ; deficiency ; genetics ; Movement Disorders ; diagnosis ; genetics ; therapy ; Mutation ; genetics ; Radiography

D-Mannitol has wide applications in food, pharmaceutical, and chemical industries. In this study, we constructed a genetically stable Escherichia coli strain for D-mannitol production by integrating mannitol dehydrogenase (mdh) and fructose permease (fupL) genes of Leuconostoc pseudomesenteroides ATCC 12291 into chromosome of E. coli ATCC 8739 and inactivating other fermentation pathways (including pyruvate formate-lyase, lactate dehydrogenase, fumarate reductase, alcohol dehydrogenase, methylglyoxal synthase and pyruvate oxidase). Using mineral salts medium with glucose and fructose as carbon sources, the engineered strain could produce 1.2 mmol/L D-mannitol after anaerobic fermentation for 6 days. Based on the coupling of cell growth and D-mannitol production, metabolic evolution was used to improve D-mannitol production. After evolution for 80 generations, D-mannitol titer increased 2.6-fold and mannitol dehydrogenase activity increased 2.8-fold. Genetically stable strains constructed in this work could ferment sugars to produce D-mannitol without the addition of antibiotics, inducers and formate, which was favorable for industrial production.
Escherichia coli ; genetics ; metabolism ; Fermentation ; Industrial Microbiology ; methods ; Leuconostoc ; enzymology ; Mannitol ; metabolism ; Mannitol Dehydrogenases ; genetics ; Metabolic Engineering ; methods ; Monosaccharide Transport Proteins ; genetics

In the present study, we show that the expression of type 2 glucose transporter isoform (GLUT2) could be regulated by PPAR-gamma in the liver. Rosiglitazone, PPAR-gamma agonist, activated the GLUT2 mRNA level in the primary cultured hepatocytes and Alexander cells, when these cells were transfected with PPAR-gamma/RXR-alpha. We have localized the peroxisome proliferator response element in the mouse GLUT2 promoter by serial deletion studies and site-directed mutagenesis. Chromatin immunoprecipitation assay using ob/ob mice also showed that PPAR-gamma rather than PPAR-alpha binds to the -197/-184 region of GLUT2 promoter. Taken together, liver GLUT2 may be a direct target of PPAR-gamma ligand contributing to glucose transport into liver in a condition when PAPR-gamma expression is increased as in type 2 diabetes or in severe obesity.
Animals ; Cells, Cultured ; Chromatin Immunoprecipitation ; Gene Expression Regulation ; Genes, Reporter ; Hepatocytes/*metabolism ; Liver/metabolism ; Male ; Mice ; Mice, Inbred ICR ; Mice, Transgenic ; Monosaccharide Transport Proteins/*biosynthesis/genetics ; Mutagenesis, Site-Directed ; PPAR alpha/genetics/metabolism ; PPAR gamma/agonists/genetics/*metabolism ; *Promoter Regions (Genetics) ; Protein Isoforms/biosynthesis ; Research Support, Non-U.S. Gov't ; *Response Elements ; Thiazolidinediones/pharmacology

It has been known that O-linked beta-N-acetylglucosamine (O-GlcNAc) modification of proteins plays an important role in transcription, translation, nuclear transport and signal transduction. The increased flux of glucose through the hexosamine biosynthetic pathway (HBP) and increased O-GlcNAc modification of protein have been suggested as one of the causes in the development of insulin resistance. However, it is not clear at the molecular level, how O-GlcNAc protein modification results in substantial impairment of insulin signaling. To clarify the association of O-GlcNAc protein modification and insulin resistance in rat primary adipocytes, we treated the adipocytes with O-(2-acetamido-2deoxy-D-glucopyranosylidene)amino-N-phenylcarbamate (PUGNAc), a potent inhibitor of O-GlcNAcase that catalyzes removal of O-GlcNAc from proteins. Prolonged treatment of PUGNAc (100 micrometer for 12 h) increased O-GlcNAc modification on proteins in adipocytes. PUGNAc also drastically decreased insulin-stimulated 2-deoxyglucose (2DG) uptake and GLUT4 translocation in adipocytes, indicating that PUGNAc developed impaired glucose utilization and insulin resistance in adipocytes. Interestingly, the O-GlcNAc modification of IRS-1 and Akt2 was increased by PUGNAc, accompanied by a partial reduction of insulin-stimulated phosphorylations of IRS-1 and Akt2. The PUGNAc treatment has no effect on the expression level of GLUT4, whereas O-GlcNAc modification of GLUT4 was increased. These results suggest that the increase of O-GlcNAc modification on insulin signal pathway intermediates, such as IRS-1 and Akt2, reduces the insulin-stimulated phosphorylation of IRS-1 and Akt2, subsequently leading to insulin resistance in rat primary adipocytes.
Acetylglucosamine/*analogs & derivatives/metabolism/pharmacology ; Adipocytes/*metabolism ; Animals ; Deoxyglucose/pharmacokinetics ; Glycosylation ; Immunoprecipitation ; *Insulin Resistance ; Male ; Monosaccharide Transport Proteins/metabolism ; Oximes/*pharmacology ; Phenylcarbamates/*pharmacology ; Phosphoproteins/*metabolism ; Phosphorylation ; Protein-Serine-Threonine Kinases/*metabolism ; Proto-Oncogene Proteins/*metabolism ; Rats ; Rats, Sprague-Dawley ; Research Support, Non-U.S. Gov't ; Subcellular Fractions/metabolism ; beta-N-Acetylhexosaminidase/antagonists & inhibitors

The specific inhibition of angiotensin II action at AT(1) receptors by losartan has been shown to decrease peripheral insulin resistance in type 2 diabetic patients and animal models. We examined the effect of losartan on the expression of insulin receptor substrate 1 (IRS-1), protein kinase B (PKB) and glucose transporter 4 (GLUT4), as well as the phosphorylation status of IRS-1 and the association between IRS-1 and phosphatidylinositol (PI) 3-kinase in skeletal muscle from fat-fed and-streptozotocin (STZ)-treated rats, an animal model of type 2 diabetes mellitus. In addition, the effects of losartan on GLUT4 translocation in muscle cells and on insulin sensitivity were also evaluated. Muscle tissues were isolated from male losartan-treated and untreated normal or non-insulin-dependent diabetes mellitus (NIDDM) rats with a dose of 4 mg/kg per day for 6 weeks. Oral administration of losartan improved insulin sensitivity, which was determined by an oral glucose tolerance test (OGTT). In skeletal muscles, the protein levels of IRS-1, PKB and GLUT4 in NIDDM rats were not significantly different from those of the control rats, and they were not affected by losartan. The levels of IRS-1 tyrosine phosphorylation, PI 3-kinase activity associated with IRS-1 and PKB activation after stimulation with insulin in muscle tissue of NIDDM rats were significantly decreased (P<0.01) compared with those in the control rats, while they were not increased by losartan. Losartan had a major effect on GLUT4 translocation in myocytes, as it significantly increased (P<0.05) the insulin-induced amounts of GLUT4 in plasma membrane (PM) and T-tubules (TT) in myocytes from NIDDM rats. Consistent with these results, the plasma glucose level in losartan-treated NIDDM rats was decreased (P<0.05) compared with that in untreated NIDDM rats. Our results suggest that losartan may exert beneficial effects on insulin resistance by increasing the translocation of GLUT4 in muscle tissue, which is probably associated with a non-PI 3-kinase-dependent mechanism.
Animals ; Diabetes Mellitus, Experimental ; blood ; drug therapy ; Diabetes Mellitus, Type 2 ; blood ; drug therapy ; physiopathology ; Glucose Transporter Type 4 ; Insulin Receptor Substrate Proteins ; Insulin Resistance ; Losartan ; pharmacology ; therapeutic use ; Male ; Monosaccharide Transport Proteins ; biosynthesis ; genetics ; Muscle Proteins ; biosynthesis ; genetics ; Muscle, Skeletal ; metabolism ; Phosphoproteins ; biosynthesis ; genetics ; Protein-Serine-Threonine Kinases ; biosynthesis ; genetics ; Proto-Oncogene Proteins ; biosynthesis ; genetics ; Proto-Oncogene Proteins c-akt ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the effect of puerarin injection on the amount of GLUT4 protein at the plasma membrane in insulin-resistant rat skeletal muscle.

METHODThe rat model of insulin resistance (IR) was made by being fed with high-fat diet. The animals were divided into three groups (ten in each group): group I: controls; group II: Insulin-resistant rats; group III: Insulin-resistant rats + Puerarin treatment. Insulin-resistant rats were injected with 100 mg puerarin injection per kg body weight through abdominal cavity once a day for 4 weeks. Fasting blood glucose and fasting serum insulin levels were measured before and after Puerarin treatment, respectively. Insulin treatment was achieved by intraperitoneal injection of insulin (1 unit insulin per kg body weight.) 15 minute before killing the animals. The right hindlimb skeletal muscle was rapidly dissected. Then the expression of GLUT4 protein at the plasma membrane in all the animals was assessed with Western blot method.

RESULTThe GLUT4 content at the plasma membrane in insulin-resistant rats skeletal muscle was significantly lower (about 31%) than that of controls (P < 0.01). Puerarin Injection partly corrected fasting blood glucose (from 6.17 +/- 0.67 mmol x L(-1) to 5.54 +/- 0.35 mmol x L(-1)) and fasting serum insulin levels (from 17.09 +/- 2.02 mU x L(-1) to 11.86 +/- 1.35 mU x L(-1)) and increased the GLUT4 content at the plasma membrane by 1.18-fold in insulin-resistant rats skeletal muscle.

CONCLUSIONPuerarin Injection can ameliorate IR, and the mechanism may be involved in increasing cell-surface level of GLUT4 through decreasing fasting blood glucose and fasting serum insulin levels, improving GLUT4 trafficking and intracellular insulin signaling.

Animals ; Cell Membrane ; metabolism ; Glucose Transporter Type 4 ; Injections ; Insulin Resistance ; Isoflavones ; administration & dosage ; isolation & purification ; pharmacology ; Male ; Monosaccharide Transport Proteins ; metabolism ; Muscle Proteins ; metabolism ; Muscle, Skeletal ; metabolism ; pathology ; Plants, Medicinal ; chemistry ; Pueraria ; chemistry ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo demonstrate the impact of hypoxia on ER-alpha in both breast cancer tissue and cell line, and its relationship with hypoxia-related parameters.

METHODSExpression of ER-alpha in 51 breast cancer patients with ER positive determined by ligand-binding assay was examined by immunohistochemistry and compared with CA-IX and Glut-1. Impact of hypoxia on breast cancer cell line MCF-7 (ER-alpha positive) was observed by Western Blot and RT-PCR.

RESULTSOf 51 breast cancer patients, 49 were ER-alpha positive. Regional decrease of ER-alpha expression was consistently observed in peri-necrotic regions as compared to distant regions in both in-situ carcinomas (n=29, P <0.0001) and invasive carcinomas (n=20, P=0.0001), which was closely associated with the induction of CA-IX and Glut-1 in hypoxia (P <0.0001). The decreased expression of ER-alpha protein and mRNA in breast cancer cell lines were attributed to hypoxia and not to other stress factors, such as reduced glucose, low pH, and products released from necrotic or hypoxic cells. Chronic intermittent hypoxia could cause persistent down-regulation of ER-alpha in the MCF-7 breast cancer cell line.

CONCLUSIONRegional hypoxia in breast cancer is associated with the reduced ER-alpha expression, and intermittent hypoxia can cause persistent down-regulation. Hypoxia may therefore contribute to the progression of ER-alpha negative status and potentially to the development of resistance to endocrine therapy.

Antigens, Neoplasm ; metabolism ; Breast ; metabolism ; pathology ; Breast Neoplasms ; metabolism ; pathology ; Carbonic Anhydrase IX ; Carbonic Anhydrases ; metabolism ; Carcinoma in Situ ; metabolism ; pathology ; Carcinoma, Ductal, Breast ; metabolism ; pathology ; Cell Hypoxia ; Cell Line, Tumor ; Down-Regulation ; Estrogen Receptor alpha ; genetics ; metabolism ; Female ; Glucose Transporter Type 1 ; Humans ; Hypoxia ; metabolism ; Monosaccharide Transport Proteins ; metabolism ; RNA, Messenger ; biosynthesis ; genetics

OBJECTIVETo investigate the effect of the escharectomy during burn shock stage on expression of glucose translator-4 (GLUT4) mRNA in skeletal muscle and adipose tissue.

METHODS30% TBSA scalded rats were employed. Escharectomy were conducted at 8 h, 24 h, 168 h after burns respectively. Insulin, glucagon, cortisol and glucose levels in serum were analyzed. RT-PCR were employed to analyze GLUT4 mRNA expression in skeletal muscle and adipose tissue.

RESULTSGlucagon, cortisol and glucose levels in serum were declined in groups which escharectomy were conducted during burn shock stage. GLUT4 mRNA expression in both skeletal muscle and adipose tissue were downregulated after burns and escharectomy conducted during burn shock stage made it restored to near normal.

CONCLUSIONGLUT4 mRNA expression will declined after major burns in skeletal muscle and adipose tissue. Escharectomy during shock stage could make it upregulated, which will be helpful to improve glucose metabolism and hypermetabolism after major burns.

Adipose Tissue ; metabolism ; Animals ; Blood Glucose ; Burns ; physiopathology ; surgery ; Gene Expression ; Glucagon ; blood ; Hydrocortisone ; blood ; Insulin ; blood ; Male ; Monosaccharide Transport Proteins ; genetics ; Muscle, Skeletal ; metabolism ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Wistar ; Reverse Transcriptase Polymerase Chain Reaction ; Shock, Traumatic ; physiopathology