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Sample records for glucose transporters expression

  1. Glucose transporters: expression, regulation and cancer

    Directory of Open Access Journals (Sweden)

    RODOLFO A. MEDINA

    2002-01-01

    Full Text Available Mammalian cells depend on glucose as a major substrate for energy production. Glucose is transported into the cell via facilitative glucose transporters (GLUT present in all cell types. Many GLUT isoforms have been described and their expression is cell-specific and subject to hormonal and environmental control. The kinetic properties and substrate specificities of the different isoforms are specifically suited to the energy requirements of the particular cell types. Due to the ubiquitousness of these transporters, their differential expression is involved in various disease states such as diabetes, ischemia and cancer. The majority of cancers and isolated cancer cell lines over-express the GLUT family members which are present in the respective tissue of origin under non-cancerous conditions. Moreover, due to the requirement of energy to feed uncontrolled proliferation, cancer cells often express GLUTs which under normal conditions would not be present in these tissues. This over-expression is predominantly associated with the likelihood of metastasis and hence poor patient prognosis. This article presents a review of the current literature on the regulation and expression of GLUT family members and has compiled clinical and research data on GLUT expression in human cancers and in isolated human cancer cell lines.

  2. Glucose transporter expression in the human colon.

    Science.gov (United States)

    Merigo, Flavia; Brandolese, Alessandro; Facchin, Sonia; Missaggia, Silvia; Bernardi, Paolo; Boschi, Federico; D'Incà, Renata; Savarino, Edoardo Vincenzo; Sbarbati, Andrea; Sturniolo, Giacomo Carlo

    2018-02-21

    To investigate by immunostaining glucose transporter expression in human colorectal mucosa in controls and patients with inflammatory bowel disease (IBD). Colorectal samples were obtained from patients undergoing lower endoscopic colonoscopy or recto-sigmoidoscopy. Patients diagnosed with ulcerative colitis ( n = 18) or Crohn's disease ( n = 10) and scheduled for diagnostic colonoscopy were enrolled. Patients who underwent colonoscopy for prevention screening of colorectal cancer or were followed-up after polypectomy or had a history of lower gastrointestinal symptoms were designated as the control group (CTRL, n = 16). Inflammatory status of the mucosa at the sampling site was evaluated histologically and/or endoscopically. A total of 147 biopsies of colorectal mucosa were collected and processed for immunohistochemistry analysis. The expression of GLUT2, SGLT1, and GLUT5 glucose transporters was investigated using immunoperoxidase labeling. To compare immunoreactivity of GLUT5 and LYVE-1, which is a marker for lymphatic vessel endothelium, double-labeled confocal microscopy was used. Immunohistochemical analysis revealed that GLUT2, SGLT1, and GLUT5 were expressed only in short epithelial portions of the large intestinal mucosa. No important differences were observed in glucose transporter expression between the samples obtained from the different portions of the colorectal tract and between the different patient groups. Unexpectedly, GLUT5 expression was also identified in vessels, mainly concentrated in specific areas where the vessels were clustered. Immunostaining with LYVE-1 and GLUT5 antibodies revealed that GLUT5-immunoreactive (-IR) clusters of vessels were concentrated in areas internal to those that were LYVE-1 positive. GLUT5 and LYVE-1 did not appear to be colocalized but rather showed a close topographical relationship on the endothelium. Based on their LYVE-1 expression, GLUT5-IR vessels were identified as lymphatic. Both inflamed and non

  3. Osteopontin upregulates the expression of glucose transporters in osteosarcoma cells.

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    I-Shan Hsieh

    Full Text Available Osteosarcoma is the most common primary malignancy of bone. Even after the traditional standard surgical therapy, metastasis still occurs in a high percentage of patients. Glucose is an important source of metabolic energy for tumor proliferation and survival. Tumors usually overexpress glucose transporters, especially hypoxia-responsive glucose transporter 1 and glucose transporter 3. Osteopontin, hypoxia-responsive glucose transporter 1, and glucose transporter 3 are overexpressed in many types of tumors and have been linked to tumorigenesis and metastasis. In this study, we investigated the regulation of glucose transporters by osteopontin in osteosarcoma. We observed that both glucose transporters and osteopontin were upregulated in hypoxic human osteosarcoma cells. Endogenously released osteopontin regulated the expression of glucose transporter 1 and glucose transporter 3 in osteosarcoma and enhanced glucose uptake into cells via the αvβ3 integrin. Knockdown of osteopontin induced cell death in 20% of osteosarcoma cells. Phloretin, a glucose transporter inhibitor, also caused cell death by treatment alone. The phloretin-induced cell death was significantly enhanced in osteopontin knockdown osteosarcoma cells. Combination of a low dose of phloretin and chemotherapeutic drugs, such as daunomycin, 5-Fu, etoposide, and methotrexate, exhibited synergistic cytotoxic effects in three osteosarcoma cell lines. Inhibition of glucose transporters markedly potentiated the apoptotic sensitivity of chemotherapeutic drugs in osteosarcoma. These results indicate that the combination of a low dose of a glucose transporter inhibitor with cytotoxic drugs may be beneficial for treating osteosarcoma patients.

  4. Effect of endurance training on glucose transport capacity and glucose transporter expression in rat skeletal muscle

    DEFF Research Database (Denmark)

    Ploug, T; Stallknecht, B M; Pedersen, O

    1990-01-01

    exhaustive single exercise session the day before experiment both maximum insulin- and contraction-stimulated transport rates were increased in all muscle types in trained rats. Accordingly, the increased glucose transport capacity in trained muscle was not due to a residual effect of the last training...... session. Half-times for reversal of contraction-induced glucose transport were similar in trained and untrained muscles. The concentrations of mRNA for GLUT-1 (the erythrocyte-brain-Hep G2 glucose transporter) and GLUT-4 (the adipocyte-muscle glucose transporter) were increased approximately twofold......The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers...

  5. Effect of endurance training on glucose transport capacity and glucose transporter expression in rat skeletal muscle

    International Nuclear Information System (INIS)

    Ploug, T.; Stallknecht, B.M.; Pedersen, O.; Kahn, B.B.; Ohkuwa, T.; Vinten, J.; Galbo, H.

    1990-01-01

    The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers and an increase of approximately 33% for contraction-stimulated transport in slow-twitch red fibers compared with nonexercised sedentary muscle. A fully additive effect of insulin and contractions was observed both in trained and untrained muscle. Compared with transport in control rats subjected to an almost exhaustive single exercise session the day before experiment both maximum insulin- and contraction-stimulated transport rates were increased in all muscle types in trained rats. Accordingly, the increased glucose transport capacity in trained muscle was not due to a residual effect of the last training session. Half-times for reversal of contraction-induced glucose transport were similar in trained and untrained muscles. The concentrations of mRNA for GLUT-1 (the erythrocyte-brain-Hep G2 glucose transporter) and GLUT-4 (the adipocyte-muscle glucose transporter) were increased approximately twofold by training in fast-twitch red muscle fibers. In parallel to this, Western blot demonstrated a approximately 47% increase in GLUT-1 protein and a approximately 31% increase in GLUT-4 protein. This indicates that the increases in maximum velocity for 3-MG transport in trained muscle is due to an increased number of glucose transporters

  6. Glucose transporter expression in human skeletal muscle fibers

    DEFF Research Database (Denmark)

    Gaster, M; Handberg, A; Beck-Nielsen, H

    2000-01-01

    The present study was initiated to investigate GLUT-1 through -5 expression in developing and mature human skeletal muscle. To bypass the problems inherent in techniques using tissue homogenates, we applied an immunocytochemical approach, employing the sensitive enhanced tyramide signal amplifica......The present study was initiated to investigate GLUT-1 through -5 expression in developing and mature human skeletal muscle. To bypass the problems inherent in techniques using tissue homogenates, we applied an immunocytochemical approach, employing the sensitive enhanced tyramide signal...... amplification (TSA) technique to detect the localization of glucose transporter expression in human skeletal muscle. We found expression of GLUT-1, GLUT-3, and GLUT-4 in developing human muscle fibers showing a distinct expression pattern. 1) GLUT-1 is expressed in human skeletal muscle cells during gestation...

  7. Glucose transporter expression in human skeletal muscle fibers

    DEFF Research Database (Denmark)

    Gaster, M; Handberg, A; Beck-Nielsen, H

    2000-01-01

    The present study was initiated to investigate GLUT-1 through -5 expression in developing and mature human skeletal muscle. To bypass the problems inherent in techniques using tissue homogenates, we applied an immunocytochemical approach, employing the sensitive enhanced tyramide signal amplifica......The present study was initiated to investigate GLUT-1 through -5 expression in developing and mature human skeletal muscle. To bypass the problems inherent in techniques using tissue homogenates, we applied an immunocytochemical approach, employing the sensitive enhanced tyramide signal...... amplification (TSA) technique to detect the localization of glucose transporter expression in human skeletal muscle. We found expression of GLUT-1, GLUT-3, and GLUT-4 in developing human muscle fibers showing a distinct expression pattern. 1) GLUT-1 is expressed in human skeletal muscle cells during gestation......, but its expression is markedly reduced around birth and is further reduced to undetectable levels within the first year of life; 2) GLUT-3 protein expression appears at 18 wk of gestation and disappears after birth; and 3) GLUT-4 protein is diffusely expressed in muscle cells throughout gestation, whereas...

  8. Regulation of expression of the arabinose and glucose transporter genes in the thermophilic archaeon Sulfolobus solfataricus

    NARCIS (Netherlands)

    Lubelska, Joanna M.; Jonuscheit, Melanie; Schleper, Christa; Albers, Sonja-Verena; Driessen, Arnold J. M.

    2006-01-01

    Sugar uptake in Sulfolobus solfataricus, a thermoacidophilic archaeon, occurs through high-affinity binding of protein-dependent ABC transporters. We have investigated the expression patterns of two sugar transport operons, that is, the glucose and arabinose transporters. Analysis of the araS

  9. Expression of hexokinases and glucose transporters in treated and untreated oesophageal adenocarcinoma

    NARCIS (Netherlands)

    Fonteyne, Philippe; Casneuf, Veerle; Pauwels, Patrick; Van Damme, Nancy; Peeters, Marc; Dierckx, Rudi; Van de Wiele, Christophe

    The aim of this study was to assess the expression pattern of the high glucose affinity glucose transporters GLUT 1, 2, 3, 4, 8 and 9 and of hexokinases I, II and III in newly diagnosed oesophageal adenocarcinoma by means of immunohistochemistry. Twenty patients eligible to undergo primary surgery

  10. Effect of endurance training on glucose transport capacity and glucose transporter expression in rat skeletal muscle

    DEFF Research Database (Denmark)

    Ploug, T; Stallknecht, B M; Pedersen, O

    1990-01-01

    The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers and an incre......The effect of 10 wk endurance swim training on 3-O-methylglucose (3-MG) uptake (at 40 mM 3-MG) in skeletal muscle was studied in the perfused rat hindquarter. Training resulted in an increase of approximately 33% for maximum insulin-stimulated 3-MG transport in fast-twitch red fibers...

  11. Role of vitamin D on the expression of glucose transporters in L6 myotubes

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    Bubblu Tamilselvan

    2013-01-01

    Full Text Available Altered expression of glucose transporters is a major characteristic of diabetes. Vitamin D has evolved widespread interest in the pathogenesis and prevention of diabetes. The present study was designed to investigate the effect of vitamin D in the overall regulation of muscle cell glucose transporter expression. L6 cells were exposed to type 1 and type 2 diabetic conditions and the effect of calcitriol (1,25, dihydroxy cholicalciferol on the expression of glucose transporters was studied by real time polymerase chain reaction (RT-PCR. There was a significant decrease in glucose transporter type 1 (GLUT1, GLUT4, vitamin D receptor (VDR, and IR expression in type 1 and 2 diabetic model compared to control group. Treatment of myoblasts with 10-7 M calcitriol for 24 h showed a significant increase in GLUT1, GLUT4, VDR, and insulin receptor (IR expression. The results indicate a potential antidiabetic function of vitamin D on GLUT1, GLUT4, VDR, and IR by improving receptor gene expression suggesting a role for vitamin D in regulation of expression of the glucose transporters in muscle cells.

  12. Cloning and functional expression of a human pancreatic islet glucose-transporter cDNA

    International Nuclear Information System (INIS)

    Permutt, M.A.; Koranyi, L.; Keller, K.; Lacy, P.E.; Scharp, D.W.; Mueckler, M.

    1989-01-01

    Previous studies have suggested that pancreatic islet glucose transport is mediated by a high-K m , low-affinity facilitated transporter similar to that expressed in liver. To determine the relationship between islet and liver glucose transporters, liver-type glucose-transporter cDNA clones were isolated from a human liver cDNA library. The liver-type glucose-transporter cDNA clone hybridized to mRNA transcripts of the same size in human liver and pancreatic islet RNA. A cDNA library was prepared from purified human pancreatic islet tissue and screened with human liver-type glucose-transporter cDNA. The authors isolated two overlapping cDNA clones encompassing 2600 base pairs, which encode a pancreatic islet protein identical in sequence to that of the putative liver-type glucose-transporter protein. Xenopus oocytes injected with synthetic mRNA transcribed from a full-length cDNA construct exhibited increased uptake of 2-deoxyglucose, confirming the functional identity of the clone. These cDNA clones can now be used to study regulation of expression of the gene and to assess the role of inherited defects in this gene as a candidate for inherited susceptibility to non-insulin-dependent diabetes mellitus

  13. Two glucose transporters in Saccharomyces cerevisiae are glucose sensors that generate a signal for induction of gene expression.

    OpenAIRE

    Ozcan, S; Dover, J; Rosenwald, A G; Wölfl, S; Johnston, M

    1996-01-01

    Glucose is the preferred carbon source for most eukaryotic cells and has profound effects on many cellular functions. How cells sense glucose and transduce a signal into the cell is a fundamental, unanswered question. Here we describe evidence that two unusual glucose transporters in the yeast Saccharomyces cerevisiae serve as glucose sensors that generate an intracellular glucose signal. The Snf3p high-affinity glucose transporter appears to function as a low glucose sensor, since it is requ...

  14. Insulin receptor and glucose transporter-4 expression in the skeletal ...

    African Journals Online (AJOL)

    Background: Stress defined as a disruption in the normal homeostatic functions of an organism caused by stressor (a physiological or psychological challenge) is ... Conclusion: Chronic stress evokes insulin insensitivity and impairs glucose metabolism through the down-regulation of INSR and GLUT4 in skeletal muscles.

  15. Transient Congenital Hypothyroidism Alters Gene Expression of Glucose Transporters and Impairs Glucose Sensing Apparatus in Young and Aged Offspring Rats

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    Hanieh Gholami

    2017-10-01

    Full Text Available Background/Aims: Transient congenital hypothyroidism (TCH could disturb carbohydrate metabolism in adulthood. Aging is associated with increased risk of type 2 diabetes. This study aims to address effects of TCH on mRNA expressions of glucose transporters (GLUTs and glucokinase (GcK in islets and insulin target tissues of aged offspring rats. Methods: The TCH group received water containing 0.025% 6-propyl-2-thiouracil during gestation. Offspring from control and TCH groups (n=6 in each group were followed until month 19. Gene expressions of GLUTs and GcK were measured at months 3 and 19. Results: Compared to controls, aged TCH rats had higher GLUT4 expression in heart (4.88 fold and soleus (6.91 fold, while expression was lower in epididymal fat (12%. In TCH rats, GLUT2 and GcK expressions in islets were lower in young (12% and 10%, respectively and higher in aged (10.85 and 8.42 fold, respectively rats. In addition, liver GLUT2 and GcK expressions were higher in young (13.11 and 21.15 fold, respectively and lower in aged rats (44% and 5%, respectively. Conclusion: Thyroid hormone deficiency during fetal period impaired glucose sensing apparatus and changed glucose transporter expression in insulin-sensitive tissues of aged offspring rats. These changes may contribute to impaired carbohydrate metabolism.

  16. Transient Congenital Hypothyroidism Alters Gene Expression of Glucose Transporters and Impairs Glucose Sensing Apparatus in Young and Aged Offspring Rats.

    Science.gov (United States)

    Gholami, Hanieh; Jeddi, Sajad; Zadeh-Vakili, Azita; Farrokhfall, Khadije; Rouhollah, Fatemeh; Zarkesh, Maryam; Ghanbari, Mahboubeh; Ghasemi, Asghar

    2017-01-01

    Transient congenital hypothyroidism (TCH) could disturb carbohydrate metabolism in adulthood. Aging is associated with increased risk of type 2 diabetes. This study aims to address effects of TCH on mRNA expressions of glucose transporters (GLUTs) and glucokinase (GcK) in islets and insulin target tissues of aged offspring rats. The TCH group received water containing 0.025% 6-propyl-2-thiouracil during gestation. Offspring from control and TCH groups (n=6 in each group) were followed until month 19. Gene expressions of GLUTs and GcK were measured at months 3 and 19. Compared to controls, aged TCH rats had higher GLUT4 expression in heart (4.88 fold) and soleus (6.91 fold), while expression was lower in epididymal fat (12%). In TCH rats, GLUT2 and GcK expressions in islets were lower in young (12% and 10%, respectively) and higher in aged (10.85 and 8.42 fold, respectively) rats. In addition, liver GLUT2 and GcK expressions were higher in young (13.11 and 21.15 fold, respectively) and lower in aged rats (44% and 5%, respectively). Thyroid hormone deficiency during fetal period impaired glucose sensing apparatus and changed glucose transporter expression in insulin-sensitive tissues of aged offspring rats. These changes may contribute to impaired carbohydrate metabolism. © 2017 The Author(s). Published by S. Karger AG, Basel.

  17. Expression of glucocorticoid receptor and glucose transporter-1 during placental development in the diabetic rat

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    Ramazan Demir

    2011-07-01

    Full Text Available In various tissues, glucocorticoids (GCs are known to downregulate glucose transport systems; however, their effects on glucose transporters (GLUTs in the placenta of a diabetic rat are unknown. Glucocorticoid hormone action within the cell is regulated by the glucocorticoid receptor (GR. Thus, this study was designed to investigate the relationship between GR and glucose transporter expression in the placenta of the diabetic rat. Our immunohistochemical results indicated that GR and glucose transporter protein 1 (GLUT 1 are expressed ubiquitously in the trophoblast and endothelial cells of the labyrinthine zone, where maternal fetal transport takes place in the rat placenta. Expression of GR in the junctional zone of the rat placenta was detected in giant cells, and in some spongiotrophoblast cells, but not in the glycogen cells. GLUT 1 was present, especially in glycogen cells during early pregnancy, and in the spongiotrophoblast cells of the junctional zone during late pregnancy. Amounts of GR and GLUT 1 protein were increased towards the end of gestation both in the control and the diabetic placenta. However, at days 17 and 19 of gestation, only the placental GR protein was significantly increased in the streptozotocin-induced diabetic rats compared to control rats. Diabetes led to a significant decrease in placental weight at gestation day 15. In contrast, at gestational days 17 and 21, the weights of the diabetic placenta were significantly increased as compared with the controls. Moreover, diabetes induced fetus intrauterine growth retardation at gestational days 13, 17 and 21. In conclusion, the localization pattern of GR and GLUT 1 proteins in the same cell types led us to believe that there might be a relationship between GR and GLUT 1 expressions at the cellular level. GLUT 1 does not play a pivotal role in diabetic pregnancies. However, placental growth abnormalities during diabetic pregnancy may be related to the amount of GR

  18. Glucose transporter expression in an avian nectarivore: the ruby-throated hummingbird (Archilochus colubris.

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    Kenneth C Welch

    Full Text Available Glucose transporter (GLUT proteins play a key role in the transport of monosaccharides across cellular membranes, and thus, blood sugar regulation and tissue metabolism. Patterns of GLUT expression, including the insulin-responsive GLUT4, have been well characterized in mammals. However, relatively little is known about patterns of GLUT expression in birds with existing data limited to the granivorous or herbivorous chicken, duck and sparrow. The smallest avian taxa, hummingbirds, exhibit some of the highest fasted and fed blood glucose levels and display an unusual ability to switch rapidly and completely between endogenous fat and exogenous sugar to fuel energetically expensive hovering flight. Despite this, nothing is known about the GLUT transporters that enable observed rapid rates of carbohydrate flux. We examined GLUT (GLUT1, 2, 3, & 4 expression in pectoralis, leg muscle, heart, liver, kidney, intestine and brain from both zebra finches (Taeniopygia guttata and ruby-throated hummingbirds (Archilochus colubris. mRNA expression of all four transporters was probed using reverse-transcription PCR (RT-PCR. In addition, GLUT1 and 4 protein expression were assayed by western blot and immunostaining. Patterns of RNA and protein expression of GLUT1-3 in both species agree closely with published reports from other birds and mammals. As in other birds, and unlike in mammals, we did not detect GLUT4. A lack of GLUT4 correlates with hyperglycemia and an uncoupling of exercise intensity and relative oxidation of carbohydrates in hummingbirds. The function of GLUTs present in hummingbird muscle tissue (e.g. GLUT1 and 3 remain undescribed. Thus, further work is necessary to determine if high capillary density, and thus surface area across which cellular-mediated transport of sugars into active tissues (e.g. muscle occurs, rather than taxon-specific differences in GLUT density or kinetics, can account for observed rapid rates of sugar flux into these

  19. Progressive increase of glucose transporter-3 (GLUT-3) expression in estrogen-induced breast carcinogenesis.

    Science.gov (United States)

    Kocdor, M A; Kocdor, H; Pereira, J S; Vanegas, J E; Russo, I H; Russo, J

    2013-01-01

    Increased glucose uptake and glycolysis are main metabolic characteristics of malignant cells. A family of glucose transporters (GLUTs) facilitates glucose movement across the plasma membranes in a tumor-specific manner. Glucose transporter-1 (GLUT-1), GLUT-3 and recently GLUT-12, have been previously shown in breast cancer cells and are found to be associated with poor prognosis. In addition, it has been shown that estrogen plays critical roles in GLUT regulation, however, the stage-specific GLUT regulation of mammary carcinogenesis is unclear. GLUT expression patterns were investigated in an in vitro-in vivo progressive, estrogen-induced, mammary carcinogenesis model which consisted of four cell lines, with same genetic background. In this model, different stages of tumor initiation and progression are represented, MCF-10F being the normal stage, E2 cells the transformed stage by estrogen, C5 cells, the invasive stage, and T4 cells the tumorigenic stage. In addition, loss of ductulogenesis and solid mass formation in collagen matrix and invasiveness of the cells were counted. Real time PCR showed that GLUT1 expression was downregulated in MCF10F after treatment with 17β-estradiol (E2), and in the invasive cell type (C5), but not in the tumor cells (T4), which had no changes compared to MCF10F. C5 and T4 cells showed the highest rate of GLUT-3 expression. These cells were also found to be associated with loss of ductulogenesis, solid mass formation and higher invasive capacity, whereas, GLUT-12 was downregulated in C5 and T4 cells. Estrogen-induced malignant transformation is associated with remarkable and progressive GLUT-3 expression, GLUT-1 re-expression at further stages, as well as GLUT-12 downregulation.

  20. Influence of preovulatory estradiol on conceptus survival and uterine glucose transporter expression

    Science.gov (United States)

    Glucose is an essential component of uterine secretions, and is delivered into the uterine lumen by glucose transporters. We have previously reported increased concentrations of glucose in uterine flushes of cows that exhibited estrus. Our objective in the present study was to determine the effects...

  1. Prognostic significance of glucose transporter-1 (GLUT1) gene expression in rectal cancer after preoperative chemoradiotherapy

    International Nuclear Information System (INIS)

    Saigusa, Susumu; Toiyama, Yuji; Tanaka, Koji; Okugawa, Yoshinaga; Fujikawa, Hiroyuki; Matsushita, Kohei; Uchida, Keiichi; Inoue, Yasuhiro; Kusunoki, Masato

    2012-01-01

    Most cancer cells exhibit increased glycolysis. The elevated glucose transporter 1 (GLUT1) expression has been reported to be associated with resistance to therapeutic agents and a poor prognosis. We wondered whether GLUT1 expression was associated with the clinical outcome in rectal cancer after preoperative chemoradiotherapy (CRT), and whether glycolysis inhibition could represent a novel anticancer treatment. We obtained total RNA from residual cancer cells using microdissection from a total of 52 rectal cancer specimens from patients who underwent preoperative CRT. We performed transcriptional analyzes, and studied the association of the GLUT1 gene expression levels with the clinical outcomes. In addition, we examined each proliferative response of three selected colorectal cancer cell lines to a glycolysis inhibitor, 3-bromopyruvic acid (3-BrPA), with regard to their expression of the GLUT1 gene. An elevated GLUT1 gene expression was associated with a high postoperative stage, the presence of lymph node metastasis, and distant recurrence. Moreover, elevated GLUT1 gene expression independently predicted both the recurrence-free and overall survival. In the in vitro studies, we observed that 3-BrPA significantly suppressed the proliferation of colon cancer cells with high GLUT1 gene expression, compared with those with low expression. An elevated GLUT1 expression may be a useful predictor of distant recurrence and poor prognosis in rectal cancer patients after preoperative CRT. (author)

  2. Glucose transporter expression and glucose metabolism in a model of hibernating myocardium in pigs

    International Nuclear Information System (INIS)

    Egert, S.; Praus, A.; Nimz, C.; Schwaiger, M.

    2004-01-01

    We were able to present results on GLUT expression in an exemplary hibernating heart in order to test the hypothesis of a differentially regulated GLUT profile responsible for increased FDG uptake. The herein reported animal fulfilled all following criteria characterizing hibernation: - A complete occlusion of the LAD after 28 days. - Dysfunctionality but viability of the LV LAD territory as characterized by wall motion abnormality and a metabolic mismatch situation. - No histopathological signs of infarction. (orig.)

  3. FOXM1 regulates glycolysis in hepatocellular carcinoma by transactivating glucose transporter 1 expression.

    Science.gov (United States)

    Shang, Runze; Pu, Meng; Li, Yu; Wang, Desheng

    2017-04-01

    The Forkhead box M1 (FOXM1) transcription factor plays crucial roles in the initiation and progression of various malignancies, including hepatocellular carcinoma (HCC). However, the mechanism by which FOXM1 regulates cancer metabolism remains unclear. In the present study, overexpression and RNA interference (RNAi) approaches were used to investigate the role of FOXM1 in the regulation of glycolysis in vitro. Luciferase reporter assays were used to explore the transcriptional regulation of the glucose transporter 1 (GLUT1) promoter by FOXM1. Then, immunohistochemical staining was used to examine the expression of FOXM1 and GLUT1 in 100 paired HCC and adjacent non-cancerous liver tissues. Chi-square test and logistic regression analysis were performed to evaluate the association between FOXM1 and GLUT1 expression with clinicopathological characteristics. Our data showed that FOXM1 promoted glycolysis in the HCC cells. FOXM1 knockdown significantly reduced the expression of GLUT1 among key glycolysis-related molecules in the different HCC cell lines. Glucose uptake and lactate production assay showed that FOXM1 positively regulated glycolysis based on GLUT1 expression. Moreover, FOXM1 overexpression increased and knockdown decreased GLUT1 expression. Luciferase reporter assays showed that the -206 to -199 bp region of the GLUT1 promoter is important for FOXM1 to enhance GLUT1 promoter activity. The results of the IHC analysis showed that the protein expression of FOXM1 and GLUT1 was closely related to the tumor histological grade and TNM stage. In addition, GLUT1 expression was also related to microvascular invasion. In conclusion, overexpression of FOXM1 and GLUT1 may play critical roles in HCC. FOXM1 promotes HCC glycolysis by transactivating GLUT1 expression.

  4. Effects of glucose and insulin administration on glucose transporter expression in the North Pacific spiny dogfish (Squalus suckleyi).

    Science.gov (United States)

    Deck, Courtney A; Gary Anderson, W; Walsh, Patrick J

    2017-06-01

    Elasmobranchs (sharks, skates, and rays) are a primarily carnivorous group of fish, consuming few carbohydrates. Further, they tend to exhibit delayed responses to glucose and insulin administration in vivo relative to mammals, leading to a presumption of glucose-intolerance. To investigate the glucoregulatory capabilities of the spiny dogfish (Squalus suckleyi), plasma glucose concentration, muscle and liver glycogen content, and glucose transporter (glut1 and 4) mRNA levels were measured following intra-arterial administration of bovine insulin (10ngkg -1 ) or an approximate doubling of fasting plasma glucose concentration. Within 6h, following glucose administration, approximately half of the introduced glucose load had been cleared, with control levels being restored by 24h post-injection. It was determined that plasma clearance was due in part to increased uptake by the tissues as muscle and liver glycogen content increased significantly, correlating with an upregulation of glut mRNA levels. Following administration of bovine insulin, plasma glucose steadily decreased through 18h before returning toward control levels. Observed decreases in plasma glucose following insulin injection were, however, relatively minor, and no increases in tissue glycogen content were observed. glut4 and glycogen synthase mRNA levels did significantly increase in the muscle in response to insulin, but no changes occurred in the liver. The responses observed mimic what occurs in mammals and teleosts, thus suggesting a conserved mechanism for glucose homeostasis in vertebrates and a high degree of glucose tolerance in these predominantly carnivorous fish. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Streptozotocin alters glucose transport, connexin expression and endoplasmic reticulum functions in neurons and astrocytes.

    Science.gov (United States)

    Biswas, Joyshree; Gupta, Sonam; Verma, Dinesh Kumar; Singh, Sarika

    2017-07-25

    The study was undertaken to explore the cell-specific streptozotocin (STZ)-induced mechanistic alterations. STZ-induced rodent model is a well-established experimental model of Alzheimer's disease (AD) and in our previous studies we have established it as an in vitro screening model of AD by employing N2A neuronal cells. Therefore, STZ was selected in the present study to understand the STZ-induced cell-specific alterations by utilizing neuronal N2A and astrocytes C6 cells. Both neuronal and astrocyte cells were treated with STZ at 10, 50, 100 and 1000μM concentrations for 48h. STZ exposure caused significant decline in cellular viability and augmented cytotoxicity of cells involving astrocytes activation. STZ treatment also disrupted the energy metabolism by altered glucose uptake and its transport in both cells as reflected with decreased expression of glucose transporters (GLUT) 1/3. The consequent decrease in ATP level and decreased mitochondrial membrane potential was also observed in both the cells. STZ caused increased intracellular calcium which could cause the initiation of endoplasmic reticulum (ER) stress. Significant upregulation of ER stress-related markers were observed in both cells after STZ treatment. The cellular communication of astrocytes and neurons was altered as reflected by increased expression of connexin 43 along with DNA fragmentation. STZ-induced apoptotic death was evaluated by elevated expression of caspase-3 and PI/Hoechst staining of cells. In conclusion, study showed that STZ exert alike biochemical alterations, ER stress and cellular apoptosis in both neuronal and astrocyte cells. Copyright © 2017 IBRO. Published by Elsevier Ltd. All rights reserved.

  6. Immunohistochemical expression of the glucose transporters Glut-1 and Glut-3 in human malignant melanomas and benign melanocytic lesions

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    Parente Paola

    2008-09-01

    Full Text Available Abstract Background Reported data indicate that cancer cells have increased rates of glucose metabolism, as determined by 18FDG-PET imaging in patients with malignancies. The results of many studies have demonstrated that the expression of glucose transporters, especially Glut-1, is increased in a variety of malignancies. This study was undertaken to assess the differential expression of Glut-1 and Glut-3 by benign and malignant melanocytic lesions. Methods Immunohistochemical staining for Glut-1 and Glut-3 was performed on paraffin-embedded tissue sections prepared from melanocytic nevi (12 cases, Spitz nevi (12 cases and primary cutaneous malignant melanomas (20 cases. Results We observed immunoreactivity for Glut-1 in all melanocytic nevi, 9 of the 12 Spitz nevi and in 9 of the 20 malignant melanomas, whereas Glut-3 was expressed in all the melanocytic lesions, both benign and malignant. Conclusion These findings indicate that the glucose transporters Glut-1 and Glut-3 play a role in the glucose metabolism of melanocytic cells. Glut-1 was present in the majority of benign nevi, whereas its expression was downregulated in 55% of malignant melanomas. Our results suggest that glucose transporter Glut-1 expression can significantly discriminate between human malignant melanoma and benign melanocytic nevi, and support the idea that additional mechanisms other than Glut-1 may contribute to glucose uptake in melanomas.

  7. Lactogenic hormones stimulate expression of lipogenic genes but not glucose transporters in bovine mammary gland.

    Science.gov (United States)

    Shao, Y; Wall, E H; McFadden, T B; Misra, Y; Qian, X; Blauwiekel, R; Kerr, D; Zhao, F-Q

    2013-02-01

    During the onset of lactation, there is a dramatic increase in the expression of glucose transporters (GLUT) and a group of enzymes involved in milk fat synthesis in the bovine mammary gland. The objective of this study was to investigate whether the lactogenic hormones mediate both of these increases. Bovine mammary explants were cultured for 48, 72, or 96 h with the following hormone treatments: no hormone (control), IGF-I, insulin (Ins), Ins + hydrocortisone + ovine prolactin (InsHPrl), or Ins + hydrocortisone + prolactin + 17β-estradiol (InsHPrlE). The relative expression of β-casein, α-lactalbumin, sterol regulatory element binding factor 1 (SREBF1), fatty acid synthase (FASN), acetyl-CoA carboxylase α (ACACA), stearyol-CoA desaturase (SCD), GLUT1, GLUT8, and GLUT12 were measured by real-time PCR. Exposure to the lactogenic hormone combinations InsHPrl and InsHPrlE for 96 h stimulated expression of β-casein and α-lactalbumin mRNA by several hundred-fold and also increased the expression of SREBF1, FASN, ACACA, and SCD genes in mammary explants (P hormone combinations had no effect on GLUT1 or GLUT8 expression and inhibited GLUT12 expression by 50% after 72 h of treatment (P hormone treatments. Moreover, treatment of dairy cows with bovine prolactin had no effect on GLUT expression in the mammary gland. In conclusion, lactogenic hormones clearly stimulate expression of milk protein and lipogenic genes, but they do not appear to mediate the marked up-regulation of GLUT expression in the mammary gland during the onset of lactation. Copyright © 2013 Elsevier Inc. All rights reserved.

  8. Expression of conventional and novel glucose transporters, GLUT1, -9, -10, and -12, in vascular smooth muscle cells

    OpenAIRE

    Pyla, Rajkumar; Poulose, Ninu; Jun, John Y.; Segar, Lakshman

    2013-01-01

    Intimal hyperplasia is characterized by exaggerated proliferation of vascular smooth muscle cells (VSMCs). Enhanced VSMC growth is dependent on increased glucose uptake and metabolism. Facilitative glucose transporters (GLUTs) are comprised of conventional GLUT isoforms (GLUT1–5) and novel GLUT isoforms (GLUT6–14). Previous studies demonstrate that GLUT1 overexpression or GLUT10 downregulation contribute to phenotypic changes in VSMCs. To date, the expression profile of all 14 GLUT isoforms h...

  9. Effects of ketamine on glucose uptake by glucose transporter type 3 expressed in Xenopus oocytes: The role of protein kinase C

    Energy Technology Data Exchange (ETDEWEB)

    Tomioka, Shigemasa, E-mail: tomioka@dent.tokushima-u.ac.jp [Department of Dental Anesthesiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Kuramoto-cho 18-15, Tokushima City, Tokushima 770-8504 (Japan); Kaneko, Miyuki [Department of Dental Anesthesiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Kuramoto-cho 18-15, Tokushima City, Tokushima 770-8504 (Japan); Satomura, Kazuhito [First Department of Oral and Maxillofacial Surgery, Institute of Health Biosciences, The University of Tokushima Graduate School, Kuramoto-cho 18-15, Tokushima City, Tokushima 770-8504 (Japan); Mikyu, Tomiko; Nakajo, Nobuyoshi [Department of Dental Anesthesiology, Institute of Health Biosciences, The University of Tokushima Graduate School, Kuramoto-cho 18-15, Tokushima City, Tokushima 770-8504 (Japan)

    2009-10-09

    We investigated the effects of ketamine on the type 3 facilitative glucose transporter (GLUT3), which plays a major role in glucose transport across the plasma membrane of neurons. Human-cloned GLUT3 was expressed in Xenopus oocytes by injection of GLUT3 mRNA. GLUT3-mediated glucose uptake was examined by measuring oocyte radioactivity following incubation with 2-deoxy-D-[1,2-{sup 3}H]glucose. While ketamine and S(+)-ketamine significantly increased GLUT3-mediated glucose uptake, this effect was biphasic such that higher concentrations of ketamine inhibited glucose uptake. Ketamine (10 {mu}M) significantly increased V{sub max} but not K{sub m} of GLUT3 for 2-deoxy-D-glucose. Although staurosporine (a protein kinase C inhibitor) increased glucose uptake, no additive or synergistic interactions were observed between staurosporine and racemic ketamine or S(+)-ketamine. Treatment with ketamine or S(+)-ketamine partially prevented GLUT3 inhibition by the protein kinase C activator phorbol-12-myrisate-13-acetate. Our results indicate that ketamine increases GLUT3 activity at clinically relevant doses through a mechanism involving PKC inhibition.

  10. Congenital vascular malformations - cerebral lesions differ from extracranial lesions by their immune expression of the glucose transporter protein GLUT1

    NARCIS (Netherlands)

    Meijer-Jorna, Lorine B.; Aronica, Eleonora; van der Loos, Chris M.; Troost, Dirk; van der Wal, Allard C.

    2012-01-01

    Background: Cerebral vascular malformations were investigated for the presence of the glucose transporter protein GLUT I, which is normally expressed in endothelial cells of the pre-existing microvasculature of the brain and absent in the vasculature of the choroid plexus and extracranial

  11. High-Affinity Glucose Transport in Aspergillus nidulans Is Mediated by the Products of Two Related but Differentially Expressed Genes

    Science.gov (United States)

    Ventura, Luisa; González, Ramón; Ramón, Daniel; MacCabe, Andrew P.

    2014-01-01

    Independent systems of high and low affinity effect glucose uptake in the filamentous fungus Aspergillus nidulans. Low-affinity uptake is known to be mediated by the product of the mstE gene. In the current work two genes, mstA and mstC, have been identified that encode high-affinity glucose transporter proteins. These proteins' primary structures share over 90% similarity, indicating that the corresponding genes share a common origin. Whilst the function of the paralogous proteins is little changed, they differ notably in their patterns of expression. The mstC gene is expressed during the early phases of germination and is subject to CreA-mediated carbon catabolite repression whereas mstA is expressed as a culture tends toward carbon starvation. In addition, various pieces of genetic evidence strongly support allelism of mstC and the previously described locus sorA. Overall, our data define MstC/SorA as a high-affinity glucose transporter expressed in germinating conidia, and MstA as a high-affinity glucose transporter that operates in vegetative hyphae under conditions of carbon limitation. PMID:24751997

  12. Comparative study of expression and activity of glucose transporters between stem cell-derived brain microvascular endothelial cells and hCMEC/D3 cells.

    Science.gov (United States)

    Al-Ahmad, Abraham J

    2017-10-01

    Glucose constitutes a major source of energy of mammalian brains. Glucose uptake at the blood-brain barrier (BBB) occurs through a facilitated glucose transport, through glucose transporter 1 (GLUT1), although other isoforms have been described at the BBB. Mutations in GLUT1 are associated with the GLUT1 deficiency syndrome, yet none of the current in vitro models of the human BBB maybe suited for modeling such a disorder. In this study, we investigated the expression of glucose transporters and glucose diffusion across brain microvascular endothelial cells (BMECs) derived from healthy patient-derived induced pluripotent stem cells (iPSCs). We investigated the expression of different glucose transporters at the BBB using immunocytochemistry and flow cytometry and measured glucose uptake and diffusion across BMEC monolayers obtained from two iPSC lines and from hCMEC/D3 cells. BMEC monolayers showed expression of several glucose transporters, in particular GLUT1, GLUT3, and GLUT4. Diffusion of glucose across the monolayers was mediated via a saturable transcellular mechanism and partially inhibited by pharmacological inhibitors. Taken together, our study suggests the presence of several glucose transporters isoforms at the human BBB and demonstrates the feasibility of modeling glucose across the BBB using patient-derived stem cells. Copyright © 2017 the American Physiological Society.

  13. Gene Expression of Glucose Transporter 1 (GLUT1), Hexokinase 1 and Hexokinase 2 in Gastroenteropancreatic Neuroendocrine Tumors

    DEFF Research Database (Denmark)

    Binderup, Tina; Knigge, Ulrich; Federspiel, Birgitte Hartnack

    2013-01-01

    Neoplastic tissue exhibits high glucose utilization and over-expression of glucose transporters (GLUTs) and hexokinases (HKs), which can be imaged by (18)F-Fluorodeoxyglucose-positron emission tomography (FDG-PET). The aim of the present study was to investigate the expression of glycolysis......-associated genes and to compare this with FDG-PET imaging as well as with the cellular proliferation index in two cancer entities with different malignant potential. Using real-time PCR, gene expression of GLUT1, HK1 and HK2 were studied in 34 neuroendocrine tumors (NETs) in comparison with 14 colorectal...... adenocarcinomas (CRAs). The Ki67 proliferation index and, when available, FDG-PET imaging was compared with gene expression. Overexpression of GLUT1 gene expression was less frequent in NETs (38%) compared to CRAs (86%), P = 0.004. HK1 was overexpressed in 41% and 71% of NETs and CRAs, respectively (P = 0...

  14. Significance of Glucose Transporter Type 1 (GLUT-1) Expression in the Therapeutic Strategy for Pancreatic Ductal Adenocarcinoma.

    Science.gov (United States)

    Kurahara, Hiroshi; Maemura, Kosei; Mataki, Yuko; Sakoda, Masahiko; Iino, Satoshi; Kawasaki, Yota; Arigami, Takaaki; Mori, Shinichiro; Kijima, Yuko; Ueno, Shinichi; Shinchi, Hiroyuki; Natsugoe, Shoji

    2018-02-05

    This study aimed to examine the prognostic relevance of glucose transporter type 1 (GLUT-1), which is a key regulator of the glucose metabolism. In particular, the study aimed to examine the association between GLUT-1 expression and the therapeutic effect of chemoradiotherapy (CRT) in pancreatic ductal adenocarcinoma (PDAC). Patients with PDAC were enrolled in the study. Patients with distant metastases and those who received only chemotherapy as treatment were excluded from the study. Specimens for immunohistochemical evaluations were obtained through surgical resection and endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of the primary tumor before any treatment. This study included 197 patients. Of these 197 patients, 100 underwent upfront surgery, and 97 received neoadjuvant CRT (NACRT), which was performed mainly for patients with locally advanced tumors. Of the 97 patients who received NACRT, 21 later underwent surgical resection. For the patients who underwent upfront surgery, low GLUT-1 expression was an independent factor for a better prognosis. For the patients who underwent NACRT, low GLUT-1 expression was significantly associated with greater tumor size reduction, a higher resection rate, and a better prognosis. Additionally, GLUT-1 expression was significantly increased after NACRT treatment. Among the patients with PDAC, those with low GLUT-1 expression in the primary tumor had a better prognosis those with high GLUT-1 expression. Moreover, the patients with low GLUT-1 expression displayed a better therapeutic response to NACRT.

  15. Macrophage migration inhibitory factor promotes expression of GLUT4 glucose transporter through MEF2 and Zac1 in cardiomyocytes.

    Science.gov (United States)

    Liang, Yeyou; Yuan, Weiwei; Zhu, Wensi; Zhu, Jiening; Lin, Qiuxiong; Zou, Xiao; Deng, Chunyu; Fu, Yongheng; Zheng, Xilong; Yang, Min; Wu, Shulin; Yu, Xiyong; Shan, Zhixin

    2015-12-01

    Evidence shows that both macrophage migration inhibitory factor (MIF) and GLUT4 glucose transporter are involved in diabetic cardiomyopathy (DCM), but it remains largely unknown whether and how MIF regulates GLUT4 expression in cardiomyocytes. The present study aims to investigate the mechanism underlying the modulation of GLUT4 by MIF in cardiomyocytes. Activations of AKT and AMPK signaling, and expressions of MIF, GLUT4 and the candidate GLUT4 regulation associated transcription factors in the diabetic mouse myocardium were determined. The screened transcription factors mediating MIF-promoted GLUT4 expression were verified by RNA interference (RNAi) and electrophoretic mobility shift assay (EMSA), respectively. MIF was increased, but GLUT4 was decreased in the diabetic mouse myocardium. MIF could enhance glucose uptake and up-regulate GLUT4 expression in NMVCs. Expressions of transcription factor MEF2A, -2C, -2D and Zac1 were significantly up-regulated in MIF-treated neonatal mouse ventricular cardiomyocytes (NMVCs), and markedly reduced in the diabetic myocardium. Knockdown of MEF2A, -2C, -2D and Zac1 could significantly inhibit glucose uptake and GLUT4 expression in cardiomyocytes. Moreover, EMSA results revealed that transcriptional activities of MEF2 and Zac1 were significantly increased in MIF-treated NMVCs. AMPK signaling was activated in MIF-stimulated NMVCs, and AMPK activator AICAR could enhance MEF2A, -2C, -2D, Zac1 and GLUT4 expression. Additionally, MIF effects were inhibited by an AMPK inhibitor compound C and siRNA targeting MIF receptor CD74, suggesting the involvement of CD74-dependent AMPK activation. Transcription factor MEF2 and Zac1 mediate MIF-induced GLUT4 expression through CD74-dependent AMPK activation in cardiomyocytes. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Inhibition of Glucose Transport by Tomatoside A, a Tomato Seed Steroidal Saponin, through the Suppression of GLUT2 Expression in Caco-2 Cells.

    Science.gov (United States)

    Li, Baorui; Terazono, Yusuke; Hirasaki, Naoto; Tatemichi, Yuki; Kinoshita, Emiko; Obata, Akio; Matsui, Toshiro

    2018-02-14

    We investigated whether tomatoside A (5α-furostane-3β,22,26-triol-3-[O-β-d-glucopyranosyl (1→2)-β-d-glucopyranosyl (1→4)-β-d-galactopyranoside] 26-O-β-d-glucopyranoside), a tomato seed saponin, may play a role in the regulation of intestinal glucose transport in human intestinal Caco-2 cells. Tomatoside A could not penetrate through Caco-2 cell monolayers, as observed in the transport experiments using liquid chromatography-mass spectrometry. The treatment of cells with 10 μM tomatoside A for 3 h resulted in a 46.0% reduction in glucose transport as compared to untreated cells. Western blotting analyses revealed that tomatoside A significantly (p transporter 2 (GLUT2) in Caco-2 cells, while no change in the expression of sodium-dependent glucose transporter 1 was observed. In glucose transport experiments, the reduced glucose transport by tomatoside A was ameliorated by a protein kinase C (PKC) inhibitor and a multidrug resistance-associated protein 2 (MRP2) inhibitor. The tomatoside A-induced reduction in glucose transport was restored in cells treated with apical sodium-dependent bile acid transporter (ASBT) siRNA or an ASBT antagonist. These findings demonstrated for the first time that the nontransportable tomato seed steroidal saponin, tomatoside A, suppressed GLUT2 expression via PKC signaling pathway during the ASBT-influx/MRP2-efflux process in Caco-2 cells.

  17. Inhibition of glucose-transporter 1 (GLUT-1) expression reversed Warburg effect in gastric cancer cell MKN45.

    Science.gov (United States)

    Zhang, Tian-Biao; Zhao, Ying; Tong, Zhao-Xue; Guan, Yi-Fu

    2015-01-01

    Glucose transporter-1 (GLUT-1) plays critical roles in cancer development and progression. Warburg effect (aerobic glycolysis) contributes greatly to tumorigenesis and could be targeted for tumor therapy. However, published data on the relationship between GLUT-1 and Warburg effect are scarce. In this study, gastric cancer cell, MKN45, was transfected with GLUT-1 shRNA using Lipofectamine 2000. Oxygen consumption, LDH activity, lactate production and cytoplasmic pyruvate were detected after MKN45 cells with GLUT-1 knockdown. In the last, hexokinase 1 (HK1), HK2, and pyruvate kinase M2 (PKM2) expression were detected by using western blot. In this study, we showed that inhibition of GLUT-1 expression reversed Warburg effect in MKN45 cells, and induced apoptosis.

  18. Expression of conventional and novel glucose transporters, GLUT1, -9, -10, and -12, in vascular smooth muscle cells

    Science.gov (United States)

    Pyla, Rajkumar; Poulose, Ninu; Jun, John Y.

    2013-01-01

    Intimal hyperplasia is characterized by exaggerated proliferation of vascular smooth muscle cells (VSMCs). Enhanced VSMC growth is dependent on increased glucose uptake and metabolism. Facilitative glucose transporters (GLUTs) are comprised of conventional GLUT isoforms (GLUT1–5) and novel GLUT isoforms (GLUT6–14). Previous studies demonstrate that GLUT1 overexpression or GLUT10 downregulation contribute to phenotypic changes in VSMCs. To date, the expression profile of all 14 GLUT isoforms has not been fully examined in VSMCs. Using the proliferative and differentiated phenotypes of human aortic VSMCs, the present study has determined the relative abundance of GLUT1–14 mRNAs by quantitative real-time PCR analysis. Twelve GLUT mRNAs excluding GLUT7 and GLUT14 were detectable in VSMCs. In the proliferative phenotype, the relative abundance of key GLUT mRNAs was GLUT1 (∼43%) > GLUT10 (∼26%) > GLUT9 (∼13%) > GLUT12 (∼4%), whereas in the differentiated phenotype the relative abundance was GLUT10 (∼28%) > GLUT1 (∼25%) > GLUT12 (∼20%) > GLUT9 (∼14%), together constituting 86–87% of total GLUT transcripts. To confirm the expression of key GLUT proteins, immunoblot and immunocytochemical analyses were performed using GLUT isoform-specific primary antibodies. The protein bands characteristic of GLUT1, -9, -10, and -12 were detected in VSMCs in parallel with respective positive controls. In particular, GLUT1 protein expression showed different molecular forms representative of altered glycosylation. While GLUT1 protein displayed a predominant distribution in the plasma membrane, GLUT9, -10, and -12 proteins were mostly distributed in the intracellular compartments. The present study provides the first direct evidence for GLUT9 and GLUT12 expression in VSMCs in conjunction with the previously identified GLUT1 and GLUT10. PMID:23302780

  19. Impact of pre-gestational and gestational diabetes mellitus on the expression of glucose transporters GLUT-1, GLUT-4 and GLUT-9 in human term placenta.

    Science.gov (United States)

    Stanirowski, Paweł Jan; Szukiewicz, Dariusz; Pyzlak, Michał; Abdalla, Nabil; Sawicki, Włodzimierz; Cendrowski, Krzysztof

    2017-03-01

    Various studies in placental tissue suggest that diabetes mellitus alters the expression of glucose transporter (GLUT) proteins, with insulin therapy being a possible modulatory factor. The aim of the present study was quantitative evaluation of the expression of glucose transporters (GLUT-1, GLUT-4, GLUT-9) in the placenta of women in both, uncomplicated and diabetic pregnancy. Additionally, the effect of insulin therapy on the expression of selected glucose transporter isoforms was analyzed. Term placental samples were obtained from healthy control (n = 25) and diabetic pregnancies, including diet-controlled gestational diabetes mellitus (GDMG1) (n = 16), insulin-controlled gestational diabetes mellitus (GDMG2) (n = 6), and pre-gestational diabetes mellitus (PGDM) (n = 6). Computer-assisted quantitative morphometry of stained placental sections was performed to determine the expression of selected glucose transporter proteins. Morphometric analysis revealed a significant increase in the expression of GLUT-4 and GLUT-9 in insulin-dependent diabetic women (GDMG2 + PGDM) as compared to both, control and GDMG1 groups (p diabetic pregnancies. In addition, insulin therapy may increase placental expression of GLUT-4 and GLUT-9, and partially GLUT-1, in women with GDMG2/PGDM.

  20. Expression and Regulation of Facilitative Glucose Transporters in Equine Insulin-Sensitive Tissue: From Physiology to Pathology

    Science.gov (United States)

    Lacombe, Véronique A.

    2014-01-01

    Glucose uptake is the rate-limiting step in glucose utilization in mammalians and is tightly regulated by a family of specialized proteins, called the facilitated glucose transporters (GLUTs/SLC2). GLUT4, the major isoform in insulin-responsive tissue, translocates from an intracellular pool to the cell surface and as such determines insulin-stimulated glucose uptake. However, despite intensive research over 50 years, the insulin-dependent and -independent pathways that mediate GLUT4 translocation are not fully elucidated in any species. Insulin resistance (IR) is one of the hallmarks of equine metabolic syndrome and is the most common metabolic predisposition for laminitis in horses. IR is characterized by the impaired ability of insulin to stimulate glucose disposal into insulin-sensitive tissues. Similar to other species, the functional capability of the insulin-responsive GLUTs is impaired in muscle and adipose tissue during IR in horses. However, the molecular mechanisms of altered glucose transport remain elusive in all species, and there is still much to learn about the physiological and pathophysiological functions of the GLUT family members, especially in regard to class III. Since GLUTs are key regulators of whole-body glucose homeostasis, they have received considerable attention as potential therapeutic targets to treat metabolic disorders in human and equine patients. PMID:24977043

  1. Inhibition of protein kinase CbetaII increases glucose uptake in 3T3-L1 adipocytes through elevated expression of glucose transporter 1 at the plasma membrane

    NARCIS (Netherlands)

    Bosch, Remko R.; Bazuine, Merlijn; Wake, Michelle M.; Span, Paul N.; Olthaar, André J.; Schürmann, Annette; Maassen, J. Antonie; Hermus, Ad R. M. M.; Willems, Peter H. G. M.; Sweep, C. G. J.

    2003-01-01

    The mechanism via which diacylglycerol-sensitive protein kinase Cs (PKCs) stimulate glucose transport in insulin-sensitive tissues is poorly defined. Phorbol esters, such as phorbol-12-myristate-13-acetate (PMA), are potent activators of conventional and novel PKCs. Addition of PMA increases the

  2. Chronic intermittent hypoxia from pedo-stage decreases glucose transporter 4 expression in adipose tissue and causes insulin resistance.

    Science.gov (United States)

    Chen, Lin; Cao, Zhao-long; Han, Fang; Gao, Zhan-cheng; He, Quan-ying

    2010-02-20

    The persistence of sleep disordered breathing (SDB) symptoms after tonsil and/or adenoid (T&A) surgery are common in children with obstructive sleep apnea (OSA). We tested the hypothesis that disturbances of glucose transporters (GLUTs) in intraabdominal adipose tissue caused by chronic intermittent hypoxia (CIH) from the pedo-period could facilitate the appearance of periphery insulin resistance in Sprague-Dawley (SD) rats. We tested the hypothesis that the changes of GLUTs in adipose tissue may be one of the reasons for persistent SDB among clinical OSA children after T&A surgery. Thirty 21-day-old SD rats were randomly divided into a CIH group, a chronic continuous hypoxia (CCH) group, and a normal oxygen group (control group) and exposed for 40 days. The changes of weight, fasting blood glucose and fasting blood insulin levels were measured. Hyperinsulinemic-euglycemic clamp techniques were used to measure insulin resistance in each animal. Real-time quantitative PCR and Western blotting were used to measure GLUT mRNA and proteins in intraabdominal adipose tissue. Additional intraabdomial white adipose tissue (WAT) was also processed into paraffin sections and directly observed for GLUTs1-4 expression. When compared with control group, CIH increased blood fasting insulin levels, (245.07 +/- 53.89) pg/ml vs. (168.63 +/- 38.70) pg/ml, P = 0.038, and decreased the mean glucose infusion rate (GIR), (7.25 +/- 1.29) mg x kg(-1) x min(-1) vs. (13.34 +/- 1.54) mg x kg(-1) x min(-1), P < 0.001. GLUT-4 mRNA and protein expression was significantly reduced after CIH compared with CCH or normal oxygen rats, 0.002 +/- 0.002 vs. 0.039 +/- 0.009, P < 0.001; 0.642 +/- 0.073 vs. 1.000 +/- 0.103, P = 0.035. CIH in young rats could induce insulin resistance via adverse effects on glycometabolism. These findings emphasize the importance of early detection and treatment of insulin insensitivity in obese childhood OSA.

  3. Pentobarbital inhibits glucose uptake, but not water transport by glucose transporter type 3.

    Science.gov (United States)

    Tomioka, Shigemasa; Kaneko, Miyuki; Nakajo, Nobuyoshi

    2012-08-01

    To understand the mechanisms underlying the neuroprotective efficacy of barbiturates, the effect of pentobarbital on glucose uptake and water transport was determined in Xenopus oocytes expressing glucose transporter type 3 (GLUT3). Pentobarbital induced a 50% concentration-dependent inhibition in glucose uptake, but exerted no effect on water transport by GLUT3. Eadie-Hofstee analysis showed that pentobarbital decreased Vmax significantly, but not Km of GLUT3 for 2-deoxy-D-glucose. Although the protein kinase C (PKC) activator significantly decreased glucose uptake by GLUT3, no additive or synergistic interactions were observed between the PKC activator and pentobarbital. Our results suggest that pentobarbital may play an important role in neuroprotection by inhibition of glucose uptake by GLUT3 by a mechanism involving PKC.

  4. Glucose Transporters in Cardiac Metabolism and Hypertrophy

    Science.gov (United States)

    Shao, Dan; Tian, Rong

    2016-01-01

    The heart is adapted to utilize all classes of substrates to meet the high-energy demand, and it tightly regulates its substrate utilization in response to environmental changes. Although fatty acids are known as the predominant fuel for the adult heart at resting stage, the heart switches its substrate preference toward glucose during stress conditions such as ischemia and pathological hypertrophy. Notably, increasing evidence suggests that the loss of metabolic flexibility associated with increased reliance on glucose utilization contribute to the development of cardiac dysfunction. The changes in glucose metabolism in hypertrophied hearts include altered glucose transport and increased glycolysis. Despite the role of glucose as an energy source, changes in other nonenergy producing pathways related to glucose metabolism, such as hexosamine biosynthetic pathway and pentose phosphate pathway, are also observed in the diseased hearts. This article summarizes the current knowledge regarding the regulation of glucose transporter expression and translocation in the heart during physiological and pathological conditions. It also discusses the signaling mechanisms governing glucose uptake in cardiomyocytes, as well as the changes of cardiac glucose metabolism under disease conditions. PMID:26756635

  5. Expression Changes in Lactate and Glucose Metabolism and Associated Transporters in Basal Ganglia following Hypoxic-Ischemic Reperfusion Injury in Piglets.

    Science.gov (United States)

    Zheng, Y; Wang, X-M

    2018-01-11

    The neonatal brain has active energy metabolism, and glucose oxidation is the major energy source of brain tissue. Lactate is produced by astrocytes and released to neurons. In the central nervous system, lactate is transported between neurons and astrocytes via the astrocyte-neuron lactate shuttle. The aim of this study was to investigate the regulatory mechanisms of energy metabolism in neurons and astrocytes in the basal ganglia of a neonatal hypoxic-ischemic brain injury piglet model. A total of 35 healthy piglets (3-5 days of age; 1.0-1.5 kg) were assigned to a control group ( n = 5) or a hypoxic-ischemic model group ( n = 30). The hypoxic-ischemic model group was further divided into 6 groups according to the 1 H-MR spectroscopy and PET/CT scan times after hypoxia-ischemia (0-2, 2-6, 6-12, 12-24, 24-48, and 48-72 hours; n = 5/group). 1 H-MR spectroscopy data were processed with LCModel software. Maximum standard uptake values refer to the maximum standard uptake values for glucose (or FDG). The maximum standard uptake values of the basal ganglia-to-occipital cortex ratio were analyzed. The expression levels of glucose transporters and monocarboxylate transporters were detected by immunohistochemical analysis. Lactate levels decreased after an initial increase, with the maximal level occurring around 2-6 hours following hypoxia-ischemia. After hypoxia-ischemia, the maximum standard uptake values of the basal ganglia and basal ganglia/occipital cortex initially increased then decreased, with the maximum occurring at approximately 6-12 hours. The lactate and glucose uptake (basal ganglia/occipital cortex maximum standard uptake values) levels were positively correlated. The expression levels of glucose transporter-1 and glucose transporter-3 were positively correlated with the basal ganglia/occipital cortex. The expression levels of monocarboxylic acid transporter-2 and monocarboxylic acid transporter-4 were positively correlated with lactate content. The

  6. Regulation of glucose transport and c-fos and egr-1 expression in cells with mutated or endogenous growth hormone receptors

    DEFF Research Database (Denmark)

    Gong, T W; Meyer, D J; Liao, J

    1998-01-01

    To identify mechanisms by which GH receptors (GHR) mediate downstream events representative of growth and metabolic responses to GH, stimulation by GH of c-fos and egr-1 expression and glucose transport activity were examined in Chinese hamster ovary (CHO) cells expressing mutated GHR. In CHO cells...... is not required for GH-stimulated c-fos transcription, suggesting that increased calcium is not required for GH-stimulated c-fos expression. In CHO cells lacking all but five N-terminal residues of the cytoplasmic domain (GHR(1-294)), GH did not induce c-fos or egr-1 expression or stimulate 2-deoxyglucose uptake...

  7. Diabetes Alters the Expression and Translocation of the Insulin-Sensitive Glucose Transporters 4 and 8 in the Atria

    Science.gov (United States)

    Maria, Zahra; Campolo, Allison R.; Lacombe, Veronique A.

    2015-01-01

    Although diabetes has been identified as a major risk factor for atrial fibrillation, little is known about glucose metabolism in the healthy and diabetic atria. Glucose transport into the cell, the rate-limiting step of glucose utilization, is regulated by the Glucose Transporters (GLUTs). Although GLUT4 is the major isoform in the heart, GLUT8 has recently emerged as a novel cardiac isoform. We hypothesized that GLUT-4 and -8 translocation to the atrial cell surface will be regulated by insulin and impaired during insulin-dependent diabetes. GLUT protein content was measured by Western blotting in healthy cardiac myocytes and type 1 (streptozotocin-induced, T1Dx) diabetic rodents. Active cell surface GLUT content was measured using a biotinylated photolabeled assay in the perfused heart. In the healthy atria, insulin stimulation increased both GLUT-4 and -8 translocation to the cell surface (by 100% and 240%, respectively, Pinsulin stimulation, we reported an increase in Akt (Th308 and s473 sites) and AS160 phosphorylation, which was positively (Pinsulin signaling pathway. This was confirmed by the rescued translocation of GLUT-4 and -8 to the atrial cell surface upon insulin stimulation in the atria of type 1 diabetic subjects. In conclusion, our data suggest that: 1) both GLUT-4 and -8 are insulin-sensitive in the healthy atria through an Akt/AS160 dependent pathway; 2) GLUT-4 and -8 trafficking is impaired in the diabetic atria and rescued by insulin treatment. Alterations in atrial glucose transport may induce perturbations in energy production, which may provide a metabolic substrate for atrial fibrillation during diabetes. PMID:26720696

  8. Resveratrol Improves Glycemic Control in Type 2 Diabetic Obese Mice by Regulating Glucose Transporter Expression in Skeletal Muscle and Liver.

    Science.gov (United States)

    Yonamine, Caio Y; Pinheiro-Machado, Erika; Michalani, Maria L; Alves-Wagner, Ana B; Esteves, João V; Freitas, Helayne S; Machado, Ubiratan F

    2017-07-14

    Insulin resistance participates in the glycaemic control disruption in type 2 diabetes mellitus (T2DM), by reducing muscle glucose influx and increasing liver glucose efflux. GLUT4 ( Slc2a4 gene) and GLUT2 ( Slc2a2 gene) proteins play a fundamental role in the muscle and liver glucose fluxes, respectively. Resveratrol is a polyphenol suggested to have an insulin sensitizer effect; however, this effect, and related mechanisms, have not been clearly demonstrated in T2DM. We hypothesized that resveratrol can improve glycaemic control by restoring GLUT4 and GLUT2 expression in muscle and liver. Mice were rendered obese T2DM in adult life by neonatal injection of monosodium glutamate. Then, T2DM mice were treated with resveratrol for 60 days or not. Glycaemic homeostasis, GLUT4, GLUT2, and SIRT1 (sirtuin 1) proteins (Western blotting); Slc2a4 , Slc2a2 , and Pck1 (key gluconeogenic enzyme codifier) mRNAs (RT-qPCR); and hepatic glucose efflux were analysed. T2DM mice revealed: high plasma concentration of glucose, fructosamine, and insulin; insulin resistance (insulin tolerance test); decreased Slc2a4 /GLUT4 content in gastrocnemius and increased Slc2a2 /GLUT2 content in liver; and increased Pck1 mRNA and gluconeogenic activity (pyruvate tolerance test) in liver. All alterations were restored by resveratrol treatment. Additionally, in both muscle and liver, resveratrol increased SIRT1 nuclear content, which must participate in gene expression regulations. In sum, the results indisputably reveals that resveratrol improves glycaemic control in T2DM, and that involves an increase in muscle Slc2a4 /GLUT4 and a decrease in liver Slc2a2 /GLUT2 expression. This study contributes to our understanding how resveratrol might be prescribed for T2DM according to the principles of evidence-based medicine.

  9. Expression of Na+/glucose co-transporter 1 (SGLT1) is enhanced by supplementation of the diet of weaning piglets with artificial sweeteners.

    Science.gov (United States)

    Moran, Andrew W; Al-Rammahi, Miran A; Arora, Daleep K; Batchelor, Daniel J; Coulter, Erin A; Daly, Kristian; Ionescu, Catherine; Bravo, David; Shirazi-Beechey, Soraya P

    2010-09-01

    In an intensive livestock production, a shorter suckling period allows more piglets to be born. However, this practice leads to a number of disorders including nutrient malabsorption, resulting in diarrhoea, malnutrition and dehydration. A number of strategies have been proposed to overcome weaning problems. Artificial sweeteners, routinely included in piglets' diet, were thought to enhance feed palatability. However, it is shown in rodent models that when included in the diet, they enhance the expression of Na+/glucose co-transporter (SGLT1) and the capacity of the gut to absorb glucose. Here, we show that supplementation of piglets' feed with a combination of artificial sweeteners saccharin and neohesperidin dihydrochalcone enhances the expression of SGLT1 and intestinal glucose transport function. Artificial sweeteners are known to act on the intestinal sweet taste receptor T1R2/T1R3 and its partner G-protein, gustducin, to activate pathways leading to SGLT1 up-regulation. Here, we demonstrate that T1R2, T1R3 and gustducin are expressed together in the enteroendocrine cells of piglet intestine. Furthermore, gut hormones secreted by the endocrine cells in response to dietary carbohydrates, glucagon-like peptides (GLP)-1, GLP-2 and glucose-dependent insulinotrophic peptide (GIP), are co-expressed with type 1 G-protein-coupled receptors (T1R) and gustducin, indicating that L- and K-enteroendocrine cells express these taste elements. In a fewer endocrine cells, T1R are also co-expressed with serotonin. Lactisole, an inhibitor of human T1R3, had no inhibitory effect on sweetener-induced SGLT1 up-regulation in piglet intestine. A better understanding of the mechanism(s) involved in sweetener up-regulation of SGLT1 will allow the identification of nutritional targets with implications for the prevention of weaning-related malabsorption.

  10. Adipocyte LDL receptor–related protein–1 expression modulates postprandial lipid transport and glucose homeostasis in mice

    Science.gov (United States)

    Hofmann, Susanna M.; Zhou, Li; Perez-Tilve, Diego; Greer, Todd; Grant, Erin; Wancata, Lauren; Thomas, Andrew; Pfluger, Paul T.; Basford, Joshua E.; Gilham, Dean; Herz, Joachim; Tschöp, Matthias H.; Hui, David Y.

    2007-01-01

    Diet-induced obesity and its serious consequences such as diabetes, cardiovascular disease, and cancer are rapidly becoming a major global health threat. Therefore, understanding the cellular and molecular mechanisms by which dietary fat causes obesity and diabetes is of paramount importance in order to identify preventive and therapeutic strategies. Increased dietary fat intake results in high plasma levels of triglyceride-rich lipoproteins (TGRL). Tissue uptake of TGRL has been shown to promote glucose intolerance. We generated mice with an adipocyte-specific inactivation of the multifunctional receptor LDL receptor–related protein–1 (LRP1) to determine its role in mediating the effects of TGRL on diet-induced obesity and diabetes. Knockout mice displayed delayed postprandial lipid clearance, reduced body weight, smaller fat stores, lipid-depleted brown adipocytes, improved glucose tolerance, and elevated energy expenditure due to enhanced muscle thermogenesis. We further demonstrated that inactivation of adipocyte LRP1 resulted in resistance to dietary fat–induced obesity and glucose intolerance. These findings identify LRP1 as a critical regulator of adipocyte energy homeostasis, where functional disruption leads to reduced lipid transport, increased insulin sensitivity, and muscular energy expenditure. PMID:17948131

  11. Lifelong Physical Activity Prevents Aging-Associated Insulin Resistance in Human Skeletal Muscle Myotubes via Increased Glucose Transporter Expression

    DEFF Research Database (Denmark)

    Bunprajun, Tipwadee; Henriksen, Tora Ida; Scheele, Camilla

    2013-01-01

    Both aging and physical inactivity are associated with increased development of insulin resistance whereas physical activity has been shown to promote increased insulin sensitivity. Here we investigated the effects of physical activity level on aging-associated insulin resistance in myotubes......, and significantly higher GLUT4 protein. It is likely that physical activity induces a number of stable adaptations, including increased GLUT4 expression that are retained in cells ex vivo and protect, or delay the onset of middle-aged-associated insulin resistance. Additionally, a sedentary lifestyle has an impact...... chain protein expression. Interestingly MHCIIa was increased only in myotubes from middle-aged active individuals. Middle-aged sedentary cells had intact insulin-stimulated Akt phosphorylation however, the same cell showed ablated insulin-stimulated glucose uptake and GLUT4 translocation to the plasma...

  12. Lifelong Physical Activity Prevents Aging-Associated Insulin Resistance in Human Skeletal Muscle Myotubes via Increased Glucose Transporter Expression.

    Science.gov (United States)

    Bunprajun, Tipwadee; Henriksen, Tora Ida; Scheele, Camilla; Pedersen, Bente Klarlund; Green, Charlotte Jane

    2013-01-01

    Both aging and physical inactivity are associated with increased development of insulin resistance whereas physical activity has been shown to promote increased insulin sensitivity. Here we investigated the effects of physical activity level on aging-associated insulin resistance in myotubes derived from human skeletal muscle satellite cells. Satellite cells were obtained from young (22 yrs) normally active or middle-aged (56.6 yrs) individuals who were either lifelong sedentary or lifelong active. Both middle-aged sedentary and middle-aged active myotubes had increased p21 and myosin heavy chain protein expression. Interestingly MHCIIa was increased only in myotubes from middle-aged active individuals. Middle-aged sedentary cells had intact insulin-stimulated Akt phosphorylation however, the same cell showed ablated insulin-stimulated glucose uptake and GLUT4 translocation to the plasma membrane. On the other hand, middle-aged active cells retained both insulin-stimulated increases in glucose uptake and GLUT4 translocation to the plasma membrane. Middle-aged active cells also had significantly higher mRNA expression of GLUT1 and GLUT4 compared to middle-aged sedentary cells, and significantly higher GLUT4 protein. It is likely that physical activity induces a number of stable adaptations, including increased GLUT4 expression that are retained in cells ex vivo and protect, or delay the onset of middle-aged-associated insulin resistance. Additionally, a sedentary lifestyle has an impact on the metabolism of human myotubes during aging and may contribute to aging-associated insulin resistance through impaired GLUT4 localization.

  13. Gene Expression of Glucose Transporter 1 (GLUT1), Hexokinase 1 and Hexokinase 2 in Gastroenteropancreatic Neuroendocrine Tumors: Correlation with F-18-fluorodeoxyglucose Positron Emission Tomography and Cellular Proliferation.

    Science.gov (United States)

    Binderup, Tina; Knigge, Ulrich Peter; Federspiel, Birgitte; Sommer, Peter; Hasselby, Jane Preuss; Loft, Annika; Kjaer, Andreas

    2013-10-29

    Neoplastic tissue exhibits high glucose utilization and over-expression of glucose transporters (GLUTs) and hexokinases (HKs), which can be imaged by (18)F-Fluorodeoxyglucose-positron emission tomography (FDG-PET). The aim of the present study was to investigate the expression of glycolysis-associated genes and to compare this with FDG-PET imaging as well as with the cellular proliferation index in two cancer entities with different malignant potential. Using real-time PCR, gene expression of GLUT1, HK1 and HK2 were studied in 34 neuroendocrine tumors (NETs) in comparison with 14 colorectal adenocarcinomas (CRAs). The Ki67 proliferation index and, when available, FDG-PET imaging was compared with gene expression. Overexpression of GLUT1 gene expression was less frequent in NETs (38%) compared to CRAs (86%), P = 0.004. HK1 was overexpressed in 41% and 71% of NETs and CRAs, respectively (P = 0.111) and HK2 was overexpressed in 50% and 64% of NETs and CRAs, respectively (P = 0.53). There was a significant correlation between the Ki67 proliferation index and GLUT1 gene expression for the NETs (R = 0.34, P = 0.047), but no correlation with the hexokinases. FDG-PET identified foci in significantly fewer NETs (36%) than CRAs (86%), (P = 0.04). The gene expression results, with less frequent GLUT1 and HK1 upregulation in NETs, confirmed the lower metabolic activity of NETs compared to the more aggressive CRAs. In accordance with this, fewer NETs were FDG-PET positive compared to CRA tumors and FDG uptake correlated with GLUT1 gene expression.

  14. Gene Expression of Glucose Transporter 1 (GLUT1, Hexokinase 1 and Hexokinase 2 in Gastroenteropancreatic Neuroendocrine Tumors: Correlation with F-18-fluorodeoxyglucose Positron Emission Tomography and Cellular Proliferation

    Directory of Open Access Journals (Sweden)

    Andreas Kjaer

    2013-10-01

    Full Text Available Neoplastic tissue exhibits high glucose utilization and over-expression of glucose transporters (GLUTs and hexokinases (HKs, which can be imaged by 18F-Fluorodeoxyglucose-positron emission tomography (FDG-PET. The aim of the present study was to investigate the expression of glycolysis-associated genes and to compare this with FDG-PET imaging as well as with the cellular proliferation index in two cancer entities with different malignant potential. Using real-time PCR, gene expression of GLUT1, HK1 and HK2 were studied in 34 neuroendocrine tumors (NETs in comparison with 14 colorectal adenocarcinomas (CRAs. The Ki67 proliferation index and, when available, FDG-PET imaging was compared with gene expression. Overexpression of GLUT1 gene expression was less frequent in NETs (38% compared to CRAs (86%, P = 0.004. HK1 was overexpressed in 41% and 71% of NETs and CRAs, respectively (P = 0.111 and HK2 was overexpressed in 50% and 64% of NETs and CRAs, respectively (P = 0.53. There was a significant correlation between the Ki67 proliferation index and GLUT1 gene expression for the NETs (R = 0.34, P = 0.047, but no correlation with the hexokinases. FDG-PET identified foci in significantly fewer NETs (36% than CRAs (86%, (P = 0.04. The gene expression results, with less frequent GLUT1 and HK1 upregulation in NETs, confirmed the lower metabolic activity of NETs compared to the more aggressive CRAs. In accordance with this, fewer NETs were FDG-PET positive compared to CRA tumors and FDG uptake correlated with GLUT1 gene expression.

  15. Diet Treatment Glucose Transporter Type 1 Deficiency (G1D)

    Science.gov (United States)

    2017-10-17

    GLUT1DS1; Epilepsy; Glut1 Deficiency Syndrome 1, Autosomal Recessive; Glucose Metabolism Disorders; Glucose Transport Defect; Glucose Transporter Type 1 Deficiency Syndrome; Glucose Transporter Protein Type 1 Deficiency Syndrome

  16. Serotonin (5-HT) Affects Expression of Liver Metabolic Enzymes and Mammary Gland Glucose Transporters during the Transition from Pregnancy to Lactation

    Science.gov (United States)

    Laporta, Jimena; Peters, Tonia L.; Merriman, Kathryn E.; Vezina, Chad M.; Hernandez, Laura L.

    2013-01-01

    The aim of this experiment was to demonstrate the ability of feeding serotonin (5-HT; 5-hydroxytryptamine) precursors to increase 5-HT production during the transition from pregnancy to lactation and the effects this has on maternal energy metabolism in the liver and mammary gland. Pregnant rats (n = 45) were fed one of three diets: I) control (CON), II) CON supplemented with 0.2% 5-hydroxytryptophan (5-HTP) or III) CON supplemented with 1.35% L-tryptophan (L-TRP), beginning on d13 of pregnancy through d9 of lactation (d9). Serum (pre and post-partum), milk (daily), liver and mammary gland tissue (d9) were collected. Serum 5-HT was increased in the 5-HTP fed dams beginning on d20 of gestation and remained elevated through d9, while it was only increased on d9 in the L-TRP fed dams. 5-HT levels were increased in mammary gland and liver of both groups. Additionally, 5-HTP fed dams had serum and milk glucose levels similar to the CON, while L-TRP had decreased serum (d9) and milk glucose (all dates evaluated). Feeding 5-HTP resulted in increased mRNA expression of key gluconeogenic and glycolytic enzymes in liver and glucose transporters 1 and 8 (GLUT-1, -8) in the mammary gland. We demonstrated the location of GLUT-8 in the mammary gland both in the epithelial and vascular endothelial cells. Finally, phosphorylated 5′ AMP-activated protein kinase (pAMPK), a known regulator of intracellular energy status, was elevated in mammary glands of 5-HTP fed dams. Our results suggest that increasing 5-HT production during the transition from pregnancy to lactation increases mRNA expression of enzymes involved in energy metabolism in the liver, and mRNA abundance and distribution of glucose transporters within the mammary gland. This suggests the possibility that 5-HT may be involved in regulating energy metabolism during the transition from pregnancy to lactation. PMID:23469086

  17. Serotonin (5-HT affects expression of liver metabolic enzymes and mammary gland glucose transporters during the transition from pregnancy to lactation.

    Directory of Open Access Journals (Sweden)

    Jimena Laporta

    Full Text Available The aim of this experiment was to demonstrate the ability of feeding serotonin (5-HT; 5-hydroxytryptamine precursors to increase 5-HT production during the transition from pregnancy to lactation and the effects this has on maternal energy metabolism in the liver and mammary gland. Pregnant rats (n = 45 were fed one of three diets: I control (CON, II CON supplemented with 0.2% 5-hydroxytryptophan (5-HTP or III CON supplemented with 1.35% L-tryptophan (L-TRP, beginning on d13 of pregnancy through d9 of lactation (d9. Serum (pre and post-partum, milk (daily, liver and mammary gland tissue (d9 were collected. Serum 5-HT was increased in the 5-HTP fed dams beginning on d20 of gestation and remained elevated through d9, while it was only increased on d9 in the L-TRP fed dams. 5-HT levels were increased in mammary gland and liver of both groups. Additionally, 5-HTP fed dams had serum and milk glucose levels similar to the CON, while L-TRP had decreased serum (d9 and milk glucose (all dates evaluated. Feeding 5-HTP resulted in increased mRNA expression of key gluconeogenic and glycolytic enzymes in liver and glucose transporters 1 and 8 (GLUT-1, -8 in the mammary gland. We demonstrated the location of GLUT-8 in the mammary gland both in the epithelial and vascular endothelial cells. Finally, phosphorylated 5' AMP-activated protein kinase (pAMPK, a known regulator of intracellular energy status, was elevated in mammary glands of 5-HTP fed dams. Our results suggest that increasing 5-HT production during the transition from pregnancy to lactation increases mRNA expression of enzymes involved in energy metabolism in the liver, and mRNA abundance and distribution of glucose transporters within the mammary gland. This suggests the possibility that 5-HT may be involved in regulating energy metabolism during the transition from pregnancy to lactation.

  18. The effect of intensive insulin therapy on the insulin-regulatable glucose transporter (GLUT4) expression in skeletal muscle in type 1 diabetes

    DEFF Research Database (Denmark)

    Andersen, P H; Vestergaard, H; Lund, S

    1993-01-01

    Studies in normal man and rodents have demonstrated that the expression of the dominant glucose transporter in skeletal muscle, GLUT4, is regulated by insulin at supraphysiological circulating levels. The present study was designed to determine whether intensified insulin replacement therapy for 24...... h given to patients with Type 1 diabetes in poor metabolic control was associated with an adaptive regulation of GLUT4 mRNA and protein levels in vastus lateralis muscle. Nine Type 1 diabetic patients with a mean HbA1c of 10.3% were included in the protocol. After intensified treatment with soluble...... of the plasma glucose concentration for at least 15 h no significant alterations occurred in the amount of GLUT4 protein (0.138 +/- 0.056, poor control vs 0.113 +/- 0.026 arb. units, improved control, p = 0.16) or GLUT4 mRNA (96432 +/- 44985, poor control vs 81395 +/- 25461 arb. units, improved control, p = 0...

  19. Correlation of Glut-1 glucose transporter expression with [{sup 18}F]FDG uptake in non-small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Higashi, Kotaro; Wang, Xiao; Xu, Linfeng; Oguchi, Manabu; Taki, Suzuka; Tonami, Hisao; Yamamoto, Itaru [Department of Radiology, Kanazawa Medical University, Ishikawa (Japan); Ueda, Yoshimichi; Sakurai, Aya; Katsuda, Shogo [Department of Pathology, Kanazawa Medical University, Ishikawa (Japan); Murakami, Manabu [Medical Research Institute, Kanazawa Medical University, Ishikawa (Japan); Seki, Hiroyasu [Department of Radiology, Kanazawa Cardiovascular Hospital, Ishikawa (Japan); Nambu, Yoshihiro [Department of Internal Medicine, Division of Respiratory Disease, Kanazawa Medical University, Ishikawa (Japan)

    2000-12-01

    Positron emission tomography (PET) with [{sup 18}F]2-fluoro-2-deoxy-D-glucose (FDG) may show negative results for bronchioloalveolar lung carcinoma. We investigated the correlation of Glut-1 glucose transporter expression with [{sup 18}F]FDG uptake in non-small cell lung cancer. Thirty-two patients with 34 non-small cell lung cancers (7 bronchioloalveolar carcinomas, 23 non-bronchioloalveolar adenocarcinomas, 3 squamous cell carcinomas, and 1 adenosquamous cell carcinoma) were studied. Final diagnoses were established by histology (via thoracotomy) in all patients. [{sup 18}F]FDG PET was performed 40 min after i.v. injection of 185 MBq [{sup 18}F]FDG. For semi-quantitative analysis of [{sup 18}F]FDG uptake, standardized uptake values (SUVs) were calculated. Glut-1 expression was studied in terms of the immunohistochemistry of paraffin sections using anti-Glut-1 antibody to determine the intensity (0-3) of Glut-1 immunoreactivity and percentage of the Glut-1-positive area. Of seven bronchioloalveolar carcinomas, six (85.7%) were negative for the expression of Glut-1, while only one (4.3%) of 23 non-bronchioloalveolar adenocarcinomas was negative (P<0.0001). The percentages of Glut-1-positive area, as well as the SUVs, were significantly lower in bronchioloalveolar carcinomas (n=7) (2.86%{+-}7.56% and 1.25{+-}0.75, respectively) than in non-bronchioloalveolar adenocarcinomas (n=23) (54.83%{+-}25.64%, P<0.0001, and 3.94{+-}1.93, P=0.001, respectively). The degree of cell differentiation correlated with the percentage of Glut-1-positive area and SUVs in adenocarcinoma of the lung. Correlations between SUVs and the intensity of Glut-1 immunoreactivity were also significant (intensities 0 and 1, n=11, SUV 1.47{+-}0.63; intensities 2 and 3, n=23, SUV 4.78{+-}2.13; P<0.0001). The percentage of Glut-1-positive area correlated significantly with SUVs (n=34, r=0.658, P<0.01). Overexpression of Glut-1 correlated with high [{sup 18}F]FDG uptake. These findings suggest that Glut

  20. Brain Glucose Transporter (Glut3) Haploinsufficiency Does Not Impair Mouse Brain Glucose Uptake

    OpenAIRE

    Stuart, Charles A.; Ross, Ian R.; Howell, Mary E. A.; McCurry, Melanie P.; Wood, Thomas G.; Ceci, Jeffrey D.; Kennel, Stephen J.; Wall, Jonathan

    2011-01-01

    Mouse brain expresses three principle glucose transporters. Glut1 is an endothelial marker and is the principal glucose transporter of the blood-brain barrier. Glut3 and Glut6 are expressed in glial cells and neural cells. A mouse line with a null allele for Glut3 has been developed. The Glut3−/− genotype is intrauterine lethal by seven days post-coitis, but the heterozygous (Glut3+/−) littermate survives, exhibiting rapid post-natal weight gain, but no seizures or other behavioral aberration...

  1. Brain Glucose Transporter (Glut3) Haploinsufficiency Does Not Impair Mouse Brain Glucose Uptake

    Science.gov (United States)

    Stuart, Charles A.; Ross, Ian R.; Howell, Mary E. A.; McCurry, Melanie P.; Wood, Thomas G.; Ceci, Jeffrey D.; Kennel, Stephen J.; Wall, Jonathan

    2011-01-01

    Mouse brain expresses three principle glucose transporters. Glut1 is an endothelial marker and is the principal glucose transporter of the blood-brain barrier. Glut3 and Glut6 are expressed in glial cells and neural cells. A mouse line with a null allele for Glut3 has been developed. The Glut3−/− genotype is intrauterine lethal by seven days post-coitis, but the heterozygous (Glut3+/−) littermate survives, exhibiting rapid post-natal weight gain, but no seizures or other behavioral aberrations. At twelve weeks of age, brain uptake of tail vein-injected 3H-2-deoxy glucose in Glut3+/− mice was not different from Glut3+/+ littermates, despite 50% less Glut3 protein expression in the brain. The brain uptake of injected 18F-2-fluoro-2-deoxy glucose was similarly not different from Glut3+/− littermates in the total amount, time course, or brain imaging in the Glut3+/− mice. Glut1 and Glut6 protein expressions evaluated by immunoblots were not affected by the diminished Glut3 expression in the Glut3+/− mice. We conclude that a 50% decrease in Glut3 is not limiting for the uptake of glucose into the mouse brain, since Glut3 haploinsufficiency does not impair brain glucose uptake or utilization. PMID:21316350

  2. The effects of critical illness on intestinal glucose sensing, transporters, and absorption.

    Science.gov (United States)

    Deane, Adam M; Rayner, Chris K; Keeshan, Alex; Cvijanovic, Nada; Marino, Zelia; Nguyen, Nam Q; Chia, Bridgette; Summers, Matthew J; Sim, Jennifer A; van Beek, Theresia; Chapman, Marianne J; Horowitz, Michael; Young, Richard L

    2014-01-01

    Providing effective enteral nutrition is important during critical illness. In health, glucose is absorbed from the small intestine via sodium-dependent glucose transporter-1 and glucose transporter-2, which may both be regulated by intestinal sweet taste receptors. We evaluated the effect of critical illness on glucose absorption and expression of intestinal sodium-dependent glucose transporter-1, glucose transporter-2, and sweet taste receptors in humans and mice. Prospective observational study in humans and mice. ICU and university-affiliated research laboratory. Human subjects were 12 critically ill patients and 12 healthy controls. In the laboratory 16-week-old mice were studied. Human subjects underwent endoscopy. Glucose (30 g) and 3-O-methylglucose (3 g), used to estimate glucose absorption, were infused intraduodenally over 30 minutes. Duodenal mucosa was biopsied before and after infusion. Mice were randomized to cecal ligation and puncture to model critical illness (n = 16) or sham laparotomy (control) (n = 8). At day 5, mice received glucose (100 mg) and 3-O-methylglucose (10 mg) infused intraduodenally prior to mucosal tissue collection. Quantitative polymerase chain reaction was performed to measure absolute (human) and relative levels of sodium-dependent glucose transporter-1, glucose transporter-2, and taste receptor type 1 member 2 (T1R2) transcripts. Blood samples were assayed for 3-O-methylglucose to estimate glucose absorption. Glucose absorption was three-fold lower in critically ill humans than in controls (p = 0.002) and reduced by a similar proportion in cecal ligation and puncture mice (p = 0.004). In critically ill patients, duodenal levels of sodium-dependent glucose transporter-1, glucose transporter-2, and T1R2 transcript were reduced 49% (p absorption, associated with reduced intestinal expression of glucose transporters (sodium-dependent glucose transporter-1 and glucose transporter-2) and sweet taste receptor transcripts

  3. Disassembly of the actin network inhibits insulin-dependent stimulation of glucose transport and prevents recruitment of glucose transporters to the plasma membrane.

    Science.gov (United States)

    Tsakiridis, T; Vranic, M; Klip, A

    1994-11-25

    In muscle and fat tissues, insulin stimulates glucose transport through the translocation of glucose transporter proteins from an intracellular storage pool to the plasma membrane. The mechanism of this translocation is unknown. We have examined the possible role of the actin microfilament network in the stimulation of glucose transport by insulin and on the distribution of glucose transporters, in differentiated L6 rat skeletal muscle cells. Insulin (10(-7) M for 30 min) caused a major reorganization of the actin network of differentiated L6 myotubes. Cytochalasin D, a widely used inhibitor of actin filament formation, caused a dose- and time-dependent disassembly of the actin network, which was associated with an 80% inhibition of the insulin stimulation of glucose transport, without affecting the basal rate of glucose uptake. L6 myotubes express three glucose transporter isoforms, named GLUT1, GLUT3, and GLUT4. Disassembly of the actin network by cytochalasin D did not affect the number of basal glucose transporters in the plasma membrane but reduced the content of all three glucose transporters in intracellular membranes and prevented their appearance at the plasma membrane response to insulin. The inhibitory effect of cytochalasin D treatment on the insulin stimulation of glucose transport occurred downstream of tyrosine phosphorylation of the insulin receptor substrate-1 and of binding of phosphatidylinositol 3-kinase to the insulin receptor substrate-1. Using immunoprecipitation of intact membranes, we detected specific association of the actin-binding protein spectrin with GLUT4 glucose transporter-containing vesicles. We conclude that an intact actin network is required for the correct intracellular localization of glucose transporters, as well as for their incorporation into the plasma membrane in response to insulin. A direct interaction may exist between the actin network and the glucose transporter vesicles which may be mediated through a spectrin

  4. SREBP-1c regulates glucose-stimulated hepatic clusterin expression

    International Nuclear Information System (INIS)

    Kim, Gukhan; Kim, Geun Hyang; Oh, Gyun-Sik; Yoon, Jin; Kim, Hae Won; Kim, Min-Seon; Kim, Seung-Whan

    2011-01-01

    Highlights: → This is the first report to show nutrient-regulated clusterin expression. → Clusterin expression in hepatocytes was increased by high glucose concentration. → SREBP-1c is directly involved in the transcriptional activation of clusterin by glucose. → This glucose-stimulated activation process is mediated through tandem E-box motifs. -- Abstract: Clusterin is a stress-response protein that is involved in diverse biological processes, including cell proliferation, apoptosis, tissue differentiation, inflammation, and lipid transport. Its expression is upregulated in a broad spectrum of diverse pathological states. Clusterin was recently reported to be associated with diabetes, metabolic syndrome, and their sequelae. However, the regulation of clusterin expression by metabolic signals was not addressed. In this study we evaluated the effects of glucose on hepatic clusterin expression. Interestingly, high glucose concentrations significantly increased clusterin expression in primary hepatocytes and hepatoma cell lines, but the conventional promoter region of the clusterin gene did not respond to glucose stimulation. In contrast, the first intronic region was transcriptionally activated by high glucose concentrations. We then defined a glucose response element (GlRE) of the clusterin gene, showing that it consists of two E-box motifs separated by five nucleotides and resembles carbohydrate response element (ChoRE). Unexpectedly, however, these E-box motifs were not activated by ChoRE binding protein (ChREBP), but were activated by sterol regulatory element binding protein-1c (SREBP-1c). Furthermore, we found that glucose induced recruitment of SREBP-1c to the E-box of the clusterin gene intronic region. Taken together, these results suggest that clusterin expression is increased by glucose stimulation, and SREBP-1c plays a crucial role in the metabolic regulation of clusterin.

  5. Expression of the major insulin regulatable glucose transporter (GLUT4) in skeletal muscle of noninsulin-dependent diabetic patients and healthy subjects before and after insulin infusion

    DEFF Research Database (Denmark)

    Andersen, P H; Lund, S; Vestergaard, H

    1993-01-01

    In a cross-sectional study we have examined the regulatory effect of insulin in vivo on the major insulin regulatable glucose transporter (GLUT4) in vastus lateralis muscle from 12 noninsulin-dependent diabetes mellitus (NIDDM) patients and 8 healthy control subjects. Insulin-stimulated glucose...... uptake rate in peripheral tissue was decreased by 41% (P 2 groups in muscle biopsies obtained...... in the basal state. In healthy subjects, 4 h of insulin infusion (2 mU/kg/min) induced a 31% reduction (P

  6. Thyroid stimulating hormone stimulates the expression of glucose transporter 2 via its receptor in pancreatic β cell line, INS-1 cells.

    Science.gov (United States)

    Lyu, Jingya; Imachi, Hitomi; Yoshimoto, Takuo; Fukunaga, Kensaku; Sato, Seisuke; Ibata, Tomohiro; Kobayashi, Toshihiro; Dong, Tao; Yonezaki, Kazuko; Yamaji, Nao; Kikuchi, Fumi; Iwama, Hisakazu; Ishikawa, Ryou; Haba, Reiji; Sugiyama, Yasunori; Zhang, Huanxiang; Murao, Koji

    2018-01-31

    Thyroid stimulating hormone (TSH) stimulates the secretion of thyroid hormones by binding the TSH receptor (TSHR). TSHR is well-known to be expressed in thyroid tissue, excepting it, TSHR has also been expressed in many other tissues. In this study, we have examined the expression of TSHR in rat pancreatic islets and evaluated the role of TSH in regulating pancreas-specific gene expression. TSHR was confirmed to be expressed in rodent pancreatic islets and its cell line, INS-1 cells. TSH directly affected the glucose uptake in INS cells by up-regulating the expression of GLUT2, and furthermore this process was blocked by SB203580, the specific inhibitor of the p38 MAPK signaling pathway. Similarly, TSH stimulated GLUT2 promoter activity, while both a dominant-negative p38MAPK α isoform (p38MAPK α-DN) and the specific inhibitor for p38MAPK α abolished the stimulatory effect of TSH on GLUT2 promoter activity. Finally, INS-1 cells treated with TSH showed increased protein level of glucokinase and enhanced glucose-stimulated insulin secretion. Together, these results confirm that TSHR is expressed in INS-1 cells and rat pancreatic islets, and suggest that activation of the p38MAPK α might be required for TSH-induced GLUT2 gene transcription in pancreatic β cells.

  7. Glucose transporter 1 localisation throughout pregnancy in the carnivore placenta

    DEFF Research Database (Denmark)

    Wooding, F.B.P.; Dantzer, Vibeke; Klisch, K.

    2007-01-01

    Glucose is one of the major fetal nutrients. Maternofetal transfer requires transport across the several placental membranes. This transfer is mediated by one or more of the fourteen known isoforms of glucose transporter. So far only Glucose Transporters 1 and 3 (GT1, GT3) have been shown to be l...

  8. Analysis of correlations between the placental expression of glucose transporters GLUT-1, GLUT-4 and GLUT-9 and selected maternal and fetal parameters in pregnancies complicated by diabetes mellitus.

    Science.gov (United States)

    Stanirowski, Paweł Jan; Szukiewicz, Dariusz; Pyzlak, Michał; Abdalla, Nabil; Sawicki, Włodzimierz; Cendrowski, Krzysztof

    2017-10-16

    The aim of the study was to analyze the correlations between the expression of glucose transporters GLUT-1, GLUT-4, and GLUT-9 in human term placenta and selected maternal and fetal parameters in pregnancies complicated by diabetes mellitus (DM). Placental samples were obtained from healthy control (n = 25) and diabetic pregnancies, including diet-controlled gestational diabetes mellitus (GDMG1) (n = 16), insulin-controlled gestational diabetes mellitus (GDMG2) (n = 6), and pregestational DM (PGDM) (n = 6). Computer-assisted quantitative morphometry of stained placental sections was performed to determine the expression of selected glucose transporter proteins. For the purposes of correlation analysis, the following parameters were selected: type of diabetes, gestational age, maternal prepregnancy body mass index (BMI), gestational weight gain, third trimester glycated hemoglobin concentration, placental weight, fetal birth weight (FBW) as well as ultrasonographic indicators of fetal adiposity, including subscapular (SSFM), abdominal (AFM), and midthigh (MTFM) fat mass measurements. In the PGDM group, the analysis demonstrated positive correlations between the placental expression of GLUT-1, GLUT-4, and GLUT-9 and FBW, AFM, and SSFM measurements (p GLUT-4 expression, FBW and SSFM were observed (p GLUTs expression (p GLUT-1 expression (p GLUT-1, GLUT-4, and GLUT-9 may be involved in the intensification of the fetal growth in pregnancies complicated by GDM/PGDM.

  9. Intratumoral Heterogeneous F 18 Fluorodeoxyglucose Uptake Corresponds with Glucose Transporter 1 and Ki-67 Expression in a Case of Krukenberg Tumor: Localization of Intratumoral Hypermetabolic Focus by Fused PET/MR

    Energy Technology Data Exchange (ETDEWEB)

    Im, Hyung Jun; Kim, Youg il; Kim, Woo Ho; Kim, Seung Hyup; Kang, Keon Wook [Seoul National Univ. College of Medicine, Seoul (Korea, Republic of)

    2011-06-15

    The expression of glucose transporters (Glut 1, Glut 3), Hexokinase II, and Ki-67 has been proposed to explain intratumoral heterogeneous F-18 fluorodeoxyglucose (FDG) uptake. We report a case of Krukenberg tumor with intratumoral heterogeneous FDG uptake which corresponded well with the expression tomography (PET)/magnetic resonance (MR) imaging was helpful for localizing the metabolically active area in the tumor specimen. This report elucidates the relationship between the intratumoral heterogeneous FDG uptake and biologic heterogeneity, and shows the usefulness of PET/MR in research on intratumoral heterogeneity.

  10. Kinetics of glucose transport in rat muscle

    DEFF Research Database (Denmark)

    Ploug, Thorkil; Galbo, Henrik; Vinten, Jørgen

    1987-01-01

    -MG concentration exhibited Michaelis-Menten kinetics. Uptake by simple diffusion could not be detected. The maximum 3-O-MG transport velocity (Vmax) was increased more by maximum isometric contractions (10- to 40-fold, depending on fiber type) than by insulin (20,000 microU/ml; 3- to 20-fold) in both red and white...... transport (apparent Km) in all three muscles, in fast-twitch fibers from 70 to approximately 7 mM and in slow-twitch fibers from 12 to 7 mM. After contractions, reversal of contraction-induced glucose transport was monoexponential in red fibers, with a half-time of 7 and 15 min in slow- and fast......-twitch fibers, respectively. In white muscle, Vmax continued to increase after contractions, reached a plateau after 10 min, and had only decreased 45% after 70 min. In contrast to the prevailing opinion, in all fiber types, reversal of contraction-induced glucose transport took place in the absence of muscle...

  11. Dehydroeburicoic Acid from Antrodia camphorata Prevents the Diabetic and Dyslipidemic State via Modulation of Glucose Transporter 4, Peroxisome Proliferator-Activated Receptor α Expression and AMP-Activated Protein Kinase Phosphorylation in High-Fat-Fed Mice

    Directory of Open Access Journals (Sweden)

    Yueh-Hsiung Kuo

    2016-06-01

    Full Text Available This study investigated the potential effects of dehydroeburicoic acid (TT, a triterpenoid compound from Antrodia camphorata, in vitro and examined the effects and mechanisms of TT on glucose and lipid homeostasis in high-fat-diet (HFD-fed mice. The in vitro study examined the effects of a MeOH crude extract (CruE of A. camphorata and Antcin K (AnK; the main constituent of fruiting body of this mushroom on membrane glucose transporter 4 (GLUT4 and phospho-Akt in C2C12 myoblasts cells. The in vitro study demonstrated that treatment with CruE, AnK and TT increased the membrane levels of glucose transporter 4 (GLUT4 and phospho-Akt at different concentrations. The animal experiments were performed for 12 weeks. Diabetic mice were randomly divided into six groups after 8 weeks of HFD-induction and treated with daily oral gavage doses of TT (at three dose levels, fenofibrate (Feno (at 0.25 g/kg body weight, metformin (Metf (at 0.3 g/kg body weight or vehicle for another 4 weeks while on an HFD diet. HFD-fed mice exhibited increased blood glucose levels. TT treatment dramatically lowered blood glucose levels by 34.2%~43.4%, which was comparable to the antidiabetic agent-Metf (36.5%. TT-treated mice reduced the HFD-induced hyperglycemia, hypertriglyceridemia, hyperinsulinemia, hyperleptinemia, and hypercholesterolemia. Membrane levels of GLUT4 were significantly higher in CruE-treated groups in vitro. Skeletal muscle membrane levels of GLUT4 were significantly higher in TT-treated mice. These groups of mice also displayed lower mRNA levels of glucose-6-phosphatase (G6 Pase, an inhibitor of hepatic glucose production. The combination of these agents produced a net hypoglycemic effect in TT-treated mice. TT treatment enhanced the expressions of hepatic and skeletal muscle AMP-activated protein kinase (AMPK phosphorylation in mice. TT-treated mice exhibited enhanced expression of hepatic fatty acid oxidation enzymes, including peroxisome proliferator

  12. The glucose sensor-like protein Hxs1 is a high-affinity glucose transporter and required for virulence in Cryptococcus neoformans.

    Directory of Open Access Journals (Sweden)

    Tong-Bao Liu

    Full Text Available Cryptococcus is a major fungal pathogen that frequently causes systemic infection in patients with compromised immunity. Glucose, an important signal molecule and the preferred carbon source for Cryptococcus, plays a critical role in fungal development and virulence. Cryptococcus contains more than 50 genes sharing high sequence homology with hexose transporters in Saccharomyces cerevisiae. However, there is no report on their function in glucose sensing or transport. In this study, we investigated two hexose transporter-like proteins (Hxs1 and Hxs2 in Cryptococcus that share the highest sequence identity with the glucose sensors Snf3 and Rgt2 in S. cerevisiae. The expression of HXS1 is repressed by high glucose, while the HXS2 expression is not regulated by glucose. Functional studies showed that Hxs1 is required for fungal resistance to oxidative stress and fungal virulence. The hxs1Δ mutant exhibited a significant reduction in glucose uptake activity, indicating that Hxs1 is required for glucose uptake. Heterologous expression of Cryptococcus HXS1 rendered the S. cerevisiae mutant lacking all 20 hexose transporters a high glucose uptake activity, demonstrating that Hxs1 functions as a glucose transporter. Heterologous expression of HXS1 in the snf3Δ rgt2Δ double mutant did not complement its growth in YPD medium containing the respiration inhibitor antimycin A, suggesting that Hxs1 may not function as a glucose sensor. Taken together, our results demonstrate that Hxs1 is a high-affinity glucose transporter and required for fungal virulence.

  13. The Glucose Sensor-Like Protein Hxs1 Is a High-Affinity Glucose Transporter and Required for Virulence in Cryptococcus neoformans

    Science.gov (United States)

    Baker, Gregory M.; Fahmy, Hany; Jiang, Linghuo; Xue, Chaoyang

    2013-01-01

    Cryptococcus is a major fungal pathogen that frequently causes systemic infection in patients with compromised immunity. Glucose, an important signal molecule and the preferred carbon source for Cryptococcus, plays a critical role in fungal development and virulence. Cryptococcus contains more than 50 genes sharing high sequence homology with hexose transporters in Saccharomyces cerevisiae. However, there is no report on their function in glucose sensing or transport. In this study, we investigated two hexose transporter-like proteins (Hxs1 and Hxs2) in Cryptococcus that share the highest sequence identity with the glucose sensors Snf3 and Rgt2 in S. cerevisiae. The expression of HXS1 is repressed by high glucose, while the HXS2 expression is not regulated by glucose. Functional studies showed that Hxs1 is required for fungal resistance to oxidative stress and fungal virulence. The hxs1Δ mutant exhibited a significant reduction in glucose uptake activity, indicating that Hxs1 is required for glucose uptake. Heterologous expression of Cryptococcus HXS1 rendered the S. cerevisiae mutant lacking all 20 hexose transporters a high glucose uptake activity, demonstrating that Hxs1 functions as a glucose transporter. Heterologous expression of HXS1 in the snf3Δ rgt2Δ double mutant did not complement its growth in YPD medium containing the respiration inhibitor antimycin A, suggesting that Hxs1 may not function as a glucose sensor. Taken together, our results demonstrate that Hxs1 is a high-affinity glucose transporter and required for fungal virulence. PMID:23691177

  14. The glucose sensor-like protein Hxs1 is a high-affinity glucose transporter and required for virulence in Cryptococcus neoformans.

    Science.gov (United States)

    Liu, Tong-Bao; Wang, Yina; Baker, Gregory M; Fahmy, Hany; Jiang, Linghuo; Xue, Chaoyang

    2013-01-01

    Cryptococcus is a major fungal pathogen that frequently causes systemic infection in patients with compromised immunity. Glucose, an important signal molecule and the preferred carbon source for Cryptococcus, plays a critical role in fungal development and virulence. Cryptococcus contains more than 50 genes sharing high sequence homology with hexose transporters in Saccharomyces cerevisiae. However, there is no report on their function in glucose sensing or transport. In this study, we investigated two hexose transporter-like proteins (Hxs1 and Hxs2) in Cryptococcus that share the highest sequence identity with the glucose sensors Snf3 and Rgt2 in S. cerevisiae. The expression of HXS1 is repressed by high glucose, while the HXS2 expression is not regulated by glucose. Functional studies showed that Hxs1 is required for fungal resistance to oxidative stress and fungal virulence. The hxs1Δ mutant exhibited a significant reduction in glucose uptake activity, indicating that Hxs1 is required for glucose uptake. Heterologous expression of Cryptococcus HXS1 rendered the S. cerevisiae mutant lacking all 20 hexose transporters a high glucose uptake activity, demonstrating that Hxs1 functions as a glucose transporter. Heterologous expression of HXS1 in the snf3Δ rgt2Δ double mutant did not complement its growth in YPD medium containing the respiration inhibitor antimycin A, suggesting that Hxs1 may not function as a glucose sensor. Taken together, our results demonstrate that Hxs1 is a high-affinity glucose transporter and required for fungal virulence.

  15. Delayed access of low body weight-selected chicks to food at hatch is associated with up-regulated pancreatic glucagon and glucose transporter gene expression.

    Science.gov (United States)

    Parker, Grace A; Sumners, Lindsay H; Zhao, Xiaoling; Honaker, Christa F; Siegel, Paul B; Cline, Mark A; Gilbert, Elizabeth R

    2015-11-01

    Chickens selected for low (LWS) and high (HWS) juvenile body weight (BW) for 55 generations differ in BW by 10-fold at selection age. High (HWR) and low (LWR) body weight-relaxed lines have been random-bred since the 46th generation. Our objective was to evaluate the developmental and nutritional regulation of pancreatic mRNA abundance of pancreatic and duodenal homeobox 1 (PDX1), preproinsulin (PPI), preproglucagon (PPG), and glucose transporter 2 (GLUT2). At day of hatch (DOH) and days 1, 3, 7, and 15 (D1, 3, 7 and 15, respectively), pancreas was collected and real time PCR was performed in Experiment 1. In Experiment 2, HWS and LWS were fed or delayed access to food for 72 h post-hatch, and pancreas collected at D15. There was an interaction of line and age for GLUT2 (P=0.001), PPI (Pfood. Thus, the first two weeks is important for maturation of pancreatic endocrine function. Long-term selection for BW is associated with differences in pancreas development, and delaying access to food at hatch may have persisting effects on glucose regulatory function. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Transmissible Gastroenteritis Virus Infection Enhances SGLT1 and GLUT2 Expression to Increase Glucose Uptake.

    Science.gov (United States)

    Dai, Lei; Hu, Wei Wei; Xia, Lu; Xia, Mi; Yang, Qian

    2016-01-01

    Transmissible gastroenteritis virus (TGEV) is a coronavirus that causes villus atrophy, followed by crypt hyperplasia, reduces the activities of intestinal digestive enzymes, and disrupts the absorption of intestinal nutrients. In vivo, TGEV primarily targets and infects intestinal epithelial cells, which play an important role in glucose absorption via the apical and basolateral transporters Na+-dependent glucose transporter 1 (SGLT1) and facilitative glucose transporter 2 (GLUT2), respectively. In this study, we therefore sought to evaluate the effects of TGEV infection on glucose uptake and SGLT1 and GLUT2 expression. Our data demonstrate that infection with TGEV resulted in increased glucose uptake and augmented expression of EGFR, SGLT1 and GLUT2. Moreover, inhibition studies showed that EGFR modulated glucose uptake in control and TGEV infected cells. Finally, high glucose absorption was subsequently found to promote TGEV replication.

  17. Regulation of glucose transport by thyroid hormone in rat ovary.

    Science.gov (United States)

    Ding, Yu; Tian, Ye; Guo, Meng; Liu, Juan; Heng, Dai; Zhu, Baochang; Yang, Yanzhou; Zhang, Cheng

    2016-11-01

    Thyroid hormone (TH) plays an important role in regulating ovarian development. However, the mechanism involved remains unclear. Evidence suggests that glucose is essential for ovarian development, and its uptake is mediated by several glucose transporter proteins (Glut). We have investigated the effects of TH on Glut in rat ovary. Immature rats were treated with 6-propyl-2-thiouracil or L-thyroxine to induce hypothyroidism (hypo) or hyperthyroidism (hyper), respectively. Ovarian weights significantly decreased in both treated groups compared with the control group, although the body weights were not markedly altered. Glut1 expression significantly decreased without further changes being detected in the other Glut isforms in the hypo group and was accompanied by minimal change in mRNA content. The expression of Glut1 decreased in the hyper group. In contrast, L-thyroxine significantly increased Glut4 mRNA level and protein content but had little effect on Glut2 and Glut3 expression. Serum glucose concentrations in the hyper group were dramatically reduced compared with those in the control group. However, the serum glucose levels in the hypo group were not significantly changed. In addition, equine chorionic gonadotropin (eCG) increased ovarian weights in both the hypo and hyper groups compared with those in the rats without eCG injection. Glut2-4 protein content was significantly increased by eCG in hyper rats. Only the Glut4 mRNA content was significantly increased by eCG in the hyper group. Although the mRNA levels were not significantly changed by eCG in the hypo group, the protein level of Glut4 was markedly up-regulated. Serum glucose levels were not significantly altered by eCG in the two groups. Thus, dysfunction of the thyroid gland changes Glut expression in rat ovary and ovarian growth, both of which are also regulated by gonadotropin.

  18. The expression pattern of the glucose transporter GLUT-5 in the testis during the spermatogenic cycle of the vespertilionid bat Scotophilus heathi.

    Science.gov (United States)

    Roy, Vikas Kumar; Krishna, Amitabh

    2013-09-15

    The aims of this study were to investigate the localization and rate of expression of GLUT-5 protein during the spermatogenic cycle of Scotophilus heathi and to determine whether the expression of testicular GLUT-5 was under androgenic control. This study showed localization of GLUT-5 mainly in the spermatogonia, spermatids, spermatozoa and Leydig cells of the testis in S. heathi. Western blot analysis showed marked variation in the rate of expression of GLUT-5 protein in the testis during the reproductive cycle, in which peak expression of GLUT-5 in the testis coincided with the period of peak spermatogenesis and mating. Treatment with flutamide (an anti-androgen) caused a dose-dependent decrease in the expression of GLUT-5 protein in the testis that suggested that the expression of GLUT-5 was under androgenic control. We propose that GLUT-5 plays an important role in the transport into spermatozoa of the fuel that is required for prolonged storage in the female genital tract in S. heathi. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Photoperiodic modulation of thyroid hormone receptor (TR-α), deiodinase-2 (Dio-2) and glucose transporters (GLUT 1 and GLUT 4) expression in testis of adult golden hamster, Mesocricetus auratus.

    Science.gov (United States)

    Verma, Rakesh; Haldar, Chandana

    2016-12-01

    Phenomenon of seasonal reproduction is being regulated by changes in day length or photoperiod. The molecular mechanism underlying the event of photoperiodic regulation of testis and thyroid functions along with glucose uptake transporters has never been reported for golden hamster, M. auratus. The present study was performed to investigate the effect of photoperiod on the expression of key thyroid hormone receptor (TR-α), deiodinase-2 (Dio-2) and glucose uptake transporters (GLUT-1 & GLUT-4) in testicular germ cell and Leydig cells, and its correlation with the testicular androgen receptor (AR), germ cell proliferation factor (PCNA) and cell survival factor (Bcl-2) in testis of adult golden hamster, Mesocricetus auratus. Hamsters were exposed to different photoperiodic regimes i.e. critical photoperiod (CP), short day (SD) and long day (LD) for 10weeks. LD induces upregulation of thyroidal and gonadal activity as evident by active thyroid gland and testicular histoarchitecture, peripheral total thyroid (tT3, tT4) and testosterone hormone profiles when compared with SD exposed hamsters. Further, LD increased the expression of testicular TR-α, Dio-2, GLUT-1, GLUT-4 along with testicular AR and glucose content thereby enhancing germ cell proliferation and survival as reflected by increased PCNA and Bcl-2 expression when compared to SD exposed hamsters. Thus, it can be suggested that testicular thyroid hormone status is being regulated by photoperiod and is possibly involved in seasonal adaptation to reproductive phenomenon of golden hamster. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Glucose-induced insulin resistance of skeletal-muscle glucose transport and uptake

    DEFF Research Database (Denmark)

    Richter, Erik; Hansen, B F; Hansen, S A

    1988-01-01

    , impairment of insulin action on muscle glucose transport and uptake. Thus maximal insulin-stimulated glucose uptake at 12 mM-glucose decreased from 34.8 +/- 1.9 to 11.5 +/- 1.1 mumol/h per g (mean +/- S.E.M., n = 10) during 5 h perfusion. This decrease in glucose uptake was accompanied by a similar change...... in the presence of glucose and insulin. The data indicate that exposure to a moderately increased glucose concentration (12 mM) leads to rapidly developing resistance of skeletal-muscle glucose transport and uptake to maximal insulin stimulation. The effect of glucose is enhanced by simultaneous insulin exposure......, whereas exposure for 5 h to insulin itself does not cause measurable resistance to maximal insulin stimulation....

  1. Milder phenotypes of glucose transporter type 1 deficiency syndrome

    NARCIS (Netherlands)

    Anand, G.; Padeniya, A.; Hanrahan, D.; Scheffer, H.; Zaiwalla, Z.; Cox, D.; Mann, N.; Hewertson, J.; Price, S.; Nemeth, A.; Arsov, T.; Scheffer, I.; Jayawant, S.; Pike, M.; McShane, T.

    2011-01-01

    Glucose transporter type 1 deficiency syndrome (GLUT1DS) is a treatable condition resulting from impaired glucose transport into the brain. The classical presentation is with infantile-onset epilepsy and severe developmental delay. Non-classical phenotypes with movement disorders and early-onset

  2. Molecular cloning and characterization of glucose transporter 1 ...

    African Journals Online (AJOL)

    Glucose transporter type-1 (glut1) and citrate synthase plays crucial role in glucose transport and regulation of tricarboxylic acid cycle (TCA) cycle in mammalian energy metabolism. The present study was aimed to clone and characterize glut1 and citrate synthase cDNA in water buffalo (Bubalus bubalis). Total of 90 ...

  3. Glucose-induced insulin resistance of skeletal-muscle glucose transport and uptake

    DEFF Research Database (Denmark)

    Richter, Erik; Hansen, B F; Hansen, S A

    1988-01-01

    in the presence of glucose and insulin. The data indicate that exposure to a moderately increased glucose concentration (12 mM) leads to rapidly developing resistance of skeletal-muscle glucose transport and uptake to maximal insulin stimulation. The effect of glucose is enhanced by simultaneous insulin exposure......, whereas exposure for 5 h to insulin itself does not cause measurable resistance to maximal insulin stimulation.......The ability of glucose and insulin to modify insulin-stimulated glucose transport and uptake was investigated in perfused skeletal muscle. Here we report that perfusion of isolated rat hindlimbs for 5 h with 12 mM-glucose and 20,000 microunits of insulin/ml leads to marked, rapidly developing...

  4. Effects of taurine on plasma glucose concentration and active glucose transport in the small intestine.

    Science.gov (United States)

    Tsuchiya, Yo; Kawamata, Koichi

    2017-11-01

    Taurine lowers blood glucose levels and improves hyperglycemia. However, its effects on glucose transport in the small intestine have not been investigated. Here, we elucidated the effect of taurine on glucose absorption in the small intestine. In the oral glucose tolerance test, addition of 10 mmol/L taurine suppressed the increase in hepatic portal glucose concentrations. To investigate whether the suppressive effect of taurine occurs via down-regulation of active glucose transport in the small intestine, we performed an assay using the everted sac of the rat jejunum. Addition of taurine to the mucosal side of the jejunum suppressed active glucose transport via sodium-glucose cotransporter 1 (SGLT1). After elimination of chloride ions from the mucosal solution, taurine did not show suppressive effects on active glucose transport. These results suggest that taurine suppressed the increase in hepatic portal glucose concentrations via suppression of SGLT1 activity in the rat jejunum, depending on chloride ions. © 2017 Japanese Society of Animal Science.

  5. GLP-1 analog raises glucose transport capacity of blood-brain barrier in Alzheimer's disease

    DEFF Research Database (Denmark)

    Gejl, M.; Brock, B.; Egefjord, L.

    2017-01-01

    Objectives: Glucose enters the brain tissue from plasma by facilitated diffusion across the two membranes of the endothelium of the blood-brain barrier (BBB), mediated by the glucose transporter 1 (GLUT1). There is evidence in Alzheimer's disease (AD) of reduction of glucose transport across...... the blood-brain barrier, due to diminished GLUT1 translocation and expression at the BBB. Reduced BBB GLUT1 expression is known to aggravate AD pathology and further impair cognitive function, implying that GLUT1 may be a potential target of therapy directed towards AD neurovascular dysfunction...... and degeneration. Hypothesis: The incretin hormone GLP-1 prevents the decline of the cerebral metabolic rate of glucose that signifies cognitive impairment, synaptic dysfunction, and disease evolution in AD, and GLP-1 may directly activate GLUT1 transport in brain capillary endothelium. For this reason, we here...

  6. Intestinal glucose transport and salinity adaptation in a euryhaline teleost

    International Nuclear Information System (INIS)

    Reshkin, S.J.; Ahearn, G.A.

    1987-01-01

    Glucose transport by upper and lower intestinal brush-border membrane vesicles of the African tilapia (Oreochromis mossambicus) was characterized in fish acclimated to either freshwater of full-strength sea water. D-[ 3 H]-glucose uptake by vesicles was stimulated by a transmembrane Na gradient, was electrogenic, and was enhanced by countertransport of either D-glucose or D-galactose. Glucose transport was greater in the upper intestine than in the lower intestine and in sea water animals rather than in fish acclimated to freshwater. Glucose influx (10-s uptake) involved both saturable and nonsaturable transport components. Sea water adaptation increased apparent glucose influx K/sub t/, J/sub max/, apparent diffusional permeability (P), and the apparent Na affinity of the cotransport system in both intestinal segments, but the stoichiometry of Na-glucose transfer (1:1) was unaffected by differential saline conditions or gut region. It is suggested that increased sugar transport in sea water animals is due to the combination of enhanced Na-binding properties and an increase in number or transfer rate of the transport proteins. Freshwater animals compensate for reduced Na affinity of the coupled process by markedly increasing the protein affinity for glucose

  7. Intracellular ascorbic acid inhibits transport of glucose by neurons, but not by astrocytes.

    Science.gov (United States)

    Castro, Maite A; Pozo, Miguel; Cortés, Christian; García, María de Los Angeles; Concha, Ilona I; Nualart, Francisco

    2007-08-01

    It has been demonstrated that glutamatergic activity induces ascorbic acid (AA) depletion in astrocytes. Additionally, different data indicate that AA may inhibit glucose accumulation in primary cultures of rat hippocampal neurons. Thus, our hypothesis postulates that AA released from the astrocytes during glutamatergic synaptic activity may inhibit glucose uptake by neurons. We observed that cultured neurons express the sodium-vitamin C cotransporter 2 and the facilitative glucose transporters (GLUT) 1 and 3, however, in hippocampal brain slices GLUT3 was the main transporter detected. Functional activity of GLUTs was confirmed by means of kinetic analysis using 2-deoxy-d-glucose. Therefore, we showed that AA, once accumulated inside the cell, inhibits glucose transport in both cortical and hippocampal neurons in culture. Additionally, we showed that astrocytes are not affected by AA. Using hippocampal slices, we observed that upon blockade of monocarboxylate utilization by alpha-cyano-4-hydroxycinnamate and after glucose deprivation, glucose could rescue neuronal response to electrical stimulation only if AA uptake is prevented. Finally, using a transwell system of separated neuronal and astrocytic cultures, we observed that glutamate can reduce glucose transport in neurons only in presence of AA-loaded astrocytes, suggesting the essential role of astrocyte-released AA in this effect.

  8. Effects of Thyroidectomy and Thyroxine on Glucose Transport ...

    African Journals Online (AJOL)

    Thyroid hormone has been known to alter glucose metabolism. This study was conducted to investigate the effect of thyroidectomy and thyroxine on glucose transport in the small intestine. Forty rats were randomly selected into four groups of ten rats. Groups one and two rats were thyroidectomised to make them ...

  9. Effect of fiber type and nutritional state on AICAR- and contraction-stimulated glucose transport in rat muscle

    DEFF Research Database (Denmark)

    Ai, Hua; Ihlemann, Jacob; Hellsten, Ylva

    2002-01-01

    )- and alpha(2)-isoforms of AMPK. Expression of both isoforms varied with fiber types, and alpha(2) was highly expressed in nuclei. In conclusion, AICAR-stimulated glucose transport varies with muscle fiber type and nutritional state. AMPK is unlikely to be the sole mediator of contraction-stimulated glucose...

  10. AICAR administration affects glucose metabolism by upregulating the novel glucose transporter, GLUT8, in equine skeletal muscle.

    Science.gov (United States)

    de Laat, M A; Robinson, M A; Gruntmeir, K J; Liu, Y; Soma, L R; Lacombe, V A

    2015-09-01

    Equine metabolic syndrome is characterized by obesity and insulin resistance (IR). Currently, there is no effective pharmacological treatment for this insidious disease. Glucose uptake is mediated by a family of glucose transporters (GLUT), and is regulated by insulin-dependent and -independent pathways, including 5-AMP-activated protein kinase (AMPK). Importantly, the activation of AMPK, by 5-aminoimidazole-4-carboxamide-1-D-ribofuranoside (AICAR) stimulates glucose uptake in both healthy and diabetic humans. However, whether AICAR promotes glucose uptake in horses has not been established. It is hypothesized that AICAR administration would enhance glucose transport in equine skeletal muscle through AMPK activation. In this study, the effect of an intravenous AICAR infusion on blood glucose and insulin concentrations, as well as on GLUT expression and AMPK activation in equine skeletal muscle (quantified by Western blotting) was examined. Upon administration, plasma AICAR rapidly reached peak concentration. Treatment with AICAR resulted in a decrease (P change in lactate concentration. The ratio of phosphorylated to total AMPK was increased (P managing IR requires investigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  11. Transport equations in an enzymatic glucose fuel cell

    Science.gov (United States)

    Jariwala, Soham; Krishnamurthy, Balaji

    2018-01-01

    A mathematical model is developed to study the effects of convective flux and operating temperature on the performance of an enzymatic glucose fuel cell with a membrane. The model assumes isothermal operating conditions and constant feed rate of glucose. The glucose fuel cell domain is divided into five sections, with governing equations describing transport characteristics in each region, namely - anode diffusion layer, anode catalyst layer (enzyme layer), membrane, cathode catalyst layer and cathode diffusion layer. The mass transport is assumed to be one-dimensional and the governing equations are solved numerically. The effects flow rate of glucose feed on the performance of the fuel cell are studied as it contributes significantly to the convective flux. The effects of operating temperature on the performance of a glucose fuel cell are also modeled. The cell performances are compared using cell polarization curves, which were found compliant with experimental observations.

  12. Effect of Papaya Seed Extract (Carica papaya Linn. on Glucose Transporter 4 (GLUT 4 Expression of Skeletal Muscle Tissue in Diabetic Mice Induced by High Fructose Diet

    Directory of Open Access Journals (Sweden)

    Devyani Diah Wulansari

    2017-08-01

    Full Text Available Ethnobotany surveys show that papaya seeds are widely used as herbs for the management of some diseases such as abdominal discomfort, pain, malaria, diabetes, obesity, and infection. This research was conducted to analyze the effect of papaya seed extract on GLUT4 expression on skeletal muscle tissue of DM type II model induced by high fructose diet. This study used 24 animals, divided into 4 groups of negative control group, treated with papaya seed extract 100 mg / kgBB, 200 mg / kgBW and 300 mg / kgBW, was adapted for 14 days then induced by fructose solution 20% Orally with a dose of 1.86 grams / kgBB for 56 days. The treatment group was given papaya seed extract in accordance with the dose of each group for 14 days. GDP levels was measured using a spectrophotometer. Skeletal muscle tissue is used on the gastrocnemius part. GLUT4 expression was measured through a Immunoreactive Score (IRS method with immunohistochemical staining using GLUT4 polyclonal antibodies. Comparative test results showed that there were significant differences between groups (p <0.05 in final GDP variables and GLUT4 expression. Pearson correlation test results show that the value p = 0.001, meaning there is a significant relationship between GLUT4 expression with final GDP levels. The result of simple linear regression analysis showed that p = 0,000 (<0,05, meaning that dose of papaya seed extract had a significant influence on GLUT4 expression.

  13. Glucose Transporters in Diabetic Kidney Disease-Friends or Foes?

    Science.gov (United States)

    Wasik, Anita A; Lehtonen, Sanna

    2018-01-01

    Diabetic kidney disease (DKD) is a major microvascular complication of diabetes and a common cause of end-stage renal disease worldwide. DKD manifests as an increased urinary protein excretion (albuminuria). Multiple studies have shown that insulin resistance correlates with the development of albuminuria in non-diabetic and diabetic patients. There is also accumulating evidence that glomerular epithelial cells or podocytes are insulin sensitive and that insulin signaling in podocytes is essential for maintaining normal kidney function. At the cellular level, the mechanisms leading to the development of insulin resistance include mutations in the insulin receptor gene, impairments in the phosphoinositide 3-kinase (PI3K)/AKT signaling pathway, or perturbations in the trafficking of glucose transporters (GLUTs), which mediate the uptake of glucose into cells. Podocytes express several GLUTs, including GLUT1, GLUT2, GLUT3, GLUT4, and GLUT8. Of these, the most studied ones are GLUT1 and GLUT4, both shown to be insulin responsive in podocytes. In the basal state, GLUT4 is preferentially located in perinuclear and cytosolic vesicular structures and to a lesser extent at the plasma membrane. After insulin stimulation, GLUT4 is sorted into GLUT4-containing vesicles (GCVs) that translocate to the plasma membrane. GCV trafficking consists of several steps, including approaching of the GCVs to the plasma membrane, tethering, and docking, after which the lipid bilayers of the GCVs and the plasma membrane fuse, delivering GLUT4 to the cell surface for glucose uptake into the cell. Studies have revealed novel molecular regulators of the GLUT trafficking in podocytes and unraveled unexpected roles for GLUT1 and GLUT4 in the development of DKD, summarized in this review. These findings pave the way for better understanding of the mechanistic pathways associated with the development and progression of DKD and aid in the development of new treatments for this devastating disease.

  14. Effect of Lithium on the Mechanism of Glucose Transport in Skeletal Muscles.

    Science.gov (United States)

    Jung, Suryun; Koh, Jinho; Kim, Sanghyun; Kim, Kijin

    2017-01-01

    While lithium is known to stimulate glucose transport into skeletal muscle, the mechanisms of the increased glucose transport by lithium in skeletal muscle are not well defined yet. We excised epitrochlearis muscles from male Wistar rats and measured the transport rates of a glucose analog into lithium-, insulin-, and muscular contraction-stimulated skeletal muscle tissue and we also analyzed the levels of cell surface glucose transport 4 using a photolabeling and multicolor immunofluorescence method. In addition, we generated a cell line that stably expresses myc-tagged GLUT4 to measure the rates of GLUT4 internalization and externalization. Lithium significantly increased 2-DG glucose transport rate in skeletal muscles; however, it was significantly lower than the stimulation induced by the maximum concentration of insulin or tetanic contraction. But co-treatment of lithium with insulin or tetanic contraction increased glucose transport rate by ∼200% more than lithium alone. When skeletal muscle tissues were treated with lithium, insulin, and muscular contraction, the levels of cell surface GLUT4 protein contents were increased similarly by ∼6-fold compared with the basal levels. When insulin or lithium stimuli were maintained, the rate of GLUT4myc internalization was significantly lower, and lithium was found to suppress the internalization of GLUT4myc more strongly. The lithium-induced increase in glucose uptake of skeletal muscles appears to increase in cell surface GLUT4 levels caused by decreased internalization of GLUT4. It is concluded that co-treatment of lithium with insulin and muscular contraction had a synergistic effect on glucose transport rate in skeletal muscle.

  15. The effect of intensive insulin therapy on the insulin-regulatable glucose transporter (GLUT4) expression in skeletal muscle in type 1 diabetes

    DEFF Research Database (Denmark)

    Andersen, P H; Vestergaard, H; Lund, S

    1993-01-01

    h given to patients with Type 1 diabetes in poor metabolic control was associated with an adaptive regulation of GLUT4 mRNA and protein levels in vastus lateralis muscle. Nine Type 1 diabetic patients with a mean HbA1c of 10.3% were included in the protocol. After intensified treatment with soluble.......54). These results suggest, that in spite of evidence that high insulin levels affect GLUT4 expression in muscle, changes in serum insulin within the physiological range do not play a major role in the short-term regulation of GLUT4 expression in Type 1 diabetic patients....

  16. False positive {sup 18}F-FDG PET in an ischial chondroblastoma; an analysis of glucose transporter 1 and hexokinase II expression

    Energy Technology Data Exchange (ETDEWEB)

    Hamada, Kenichiro [Osaka University Graduate School of Medicine, Department of Nuclear Medicine and Tracer Kinetics, Osaka (Japan); Osaka University Graduate School of Medicine, Department of Orthopaedics, Osaka (Japan); Ueda, Takafumi; Tamai, Noriyuki; Myoui, Akira; Yoshikawa, Hideki [Osaka University Graduate School of Medicine, Department of Orthopaedics, Osaka (Japan); Tomita, Yasuhiko; Aozasa, Katsuyuki [Osaka University Graduate School of Medicine, Pathology, Osaka (Japan); Higuchi, Ichiro; Hatazawa, Jun [Osaka University Graduate School of Medicine, Department of Nuclear Medicine and Tracer Kinetics, Osaka (Japan); Inoue, Atsuo [Osaka University Graduate School of Medicine, Radiology, Osaka (Japan)

    2006-05-15

    We report a rare case of chondroblastoma arising from the ischium which showed an increased {sup 18}F-FDG uptake. Chondroblastoma is an uncommon lesion and usually involves the epiphysis of long bones. However, in this case, the tumor appeared as a well-defined osteolytic lesion in the ischium on radiographs. MR imaging demonstrated two components in the tumor: a solid one and a multilobular cystic component. {sup 18}F-FDG PET imaging revealed an increased uptake in the ischium. The {sup 18}F-FDG uptake resembled the results observed in malignant bone tumors. A histological diagnosis of chondroblastoma was obtained from tissue of an open biopsy. An immunohistochemical analysis demonstrated weak expression of both Glut-1 and HK-II. These findings suggest that Glut-1 and HK-II expression are not strongly related to FDG uptake in chondroblastoma. (orig.)

  17. Water transport by the Na+/glucose cotransporter under isotonic conditions

    DEFF Research Database (Denmark)

    Zeuthen, T; Meinild, A K; Klaerke, D A

    1997-01-01

    Solute cotransport in the Na+/glucose cotransporter is directly coupled to significant water fluxes. The water fluxes are energized by the downhill fluxes of the other substrates by a mechanism within the protein itself. In the present paper we investigate the Na+/glucose cotransporter expressed ...... of water molecules and the number of Na+ ions transported, equivalent to 390 water molecules per glucose molecule. Unstirred layer effects are ruled out on the basis of experiments on native oocytes incubated with the ionophores gramicidin D or nystatin....

  18. The FDG uptake and glucose transporter(GLUT-1) expression of the mediastinal nodes in the non-small cell lung cancer

    International Nuclear Information System (INIS)

    Baik, Hee Jong; Jung, Jin Haeng

    2000-12-01

    The aim of this study was to understand the mechanism of FDG uptake in the mediastinal nodes, and improve the accuracy of mediastinal staging of non-small cell lung cancer by PET. To evaluate factors determining the FDG uptake in mediastinal nodes, FDG-PET was performed preoperatively, and mediastinal dissection with pulmonary resection was done in 20 LSCLC patients. The GLUT-1 expression was studied by immunohistochemistry of paraffin-section from the mediastinal nodes(n=50, true positive 11, true negative 23, false positive 11, false negative 5) using the antiGLUT-1 antibody. The staining intensity of tumor(grade 0-4), percentage of tumor, level of follicular hyperplasia(grade 1-4), and staining intensity of follicle was also studied. The staining intensity of true positive nodes was higher than that of false negative group(Mann-Whitney test, P=0.07) in the metastased nodes. The level of follicular hyperplasia of false positive nodes was higher than that of true negative nodes in non-metastased nodes(P=0.02). This finding indicates that FN interpretation of mediastinal nodes by FDG-PET might be associated with low uptake of FDG due to low expression of GLUT-1, and that FP might be associated with high level of follicular hyperplasia as a reactive change to inflammatory and/or immune reaction

  19. The FDG uptake and glucose transporter(GLUT-1) expression of the mediastinal nodes in the non-small cell lung cancer

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Hee Jong; Jung, Jin Haeng

    2000-12-01

    The aim of this study was to understand the mechanism of FDG uptake in the mediastinal nodes, and improve the accuracy of mediastinal staging of non-small cell lung cancer by PET. To evaluate factors determining the FDG uptake in mediastinal nodes, FDG-PET was performed preoperatively, and mediastinal dissection with pulmonary resection was done in 20 LSCLC patients. The GLUT-1 expression was studied by immunohistochemistry of paraffin-section from the mediastinal nodes(n=50, true positive 11, true negative 23, false positive 11, false negative 5) using the antiGLUT-1 antibody. The staining intensity of tumor(grade 0-4), percentage of tumor, level of follicular hyperplasia(grade 1-4), and staining intensity of follicle was also studied. The staining intensity of true positive nodes was higher than that of false negative group(Mann-Whitney test, P=0.07) in the metastased nodes. The level of follicular hyperplasia of false positive nodes was higher than that of true negative nodes in non-metastased nodes(P=0.02). This finding indicates that FN interpretation of mediastinal nodes by FDG-PET might be associated with low uptake of FDG due to low expression of GLUT-1, and that FP might be associated with high level of follicular hyperplasia as a reactive change to inflammatory and/or immune reaction.

  20. Modulation of intestinal glucose transport in response to reduced nitrogen supply in young goats.

    Science.gov (United States)

    Muscher-Banse, A S; Piechotta, M; Schröder, B; Breves, G

    2012-12-01

    The reduction of dietary protein is a common approach in ruminants to decrease the excretion of N because ruminants are able to recycle N efficiently by the rumino-hepatic circulation. In nonruminant species an impact on other metabolic pathways such as glucose metabolism was observed when dietary protein intake was reduced. However, an impact of dietary N reduction in goats on glucose metabolism especially on intestinal glucose absorption is questionable because ruminants have very efficient endogenous recycling mechanisms. Therefore, the aim of the present study was to characterize the intestinal absorption of glucose in growing goats kept on different N supply under isoenergetic conditions. The different CP concentrations (20, 16, 10, 9, and 7% CP) of the experimental diets were adjusted by adding urea to the rations. Intestinal flux rates of glucose were determined by Ussing chamber experiments. For a more mechanistic approach, the Na(+)-dependent uptake of glucose into intestinal brush-border membrane vesicles (BBMV) and the expression patterns of the Na(+)-dependent glucose transporter SGLT1 and the glucose transporter 2 (GLUT2) were determined. Reduced N intake resulted in a decrease of plasma glucose (P < 0.001) and insulin (P = 0.004) concentrations whereas the intestinal flux rates of glucose were elevated (P < 0.001), which were inhibited by phlorizin. However, the uptake of glucose into intestinal BBMV was not changed whereas the expression of SGLT1 on mRNA (P < 0.05) and protein abundance (P = 0.03) was decreased in response to a reduced N intake. The mRNA expression of GLUT2 was not affected. From these data, it can be concluded that the intestinal absorption of glucose was modulated by changes in dietary N intake. It is suggested that intracellular metabolism or basolateral transport systems or both might be activated during this feeding regimen because the apical located SGLT1 might not be involved. Therefore, an impact of dietary N reduction on

  1. Glucose uptake and its effect on gene expression in prochlorococcus.

    Directory of Open Access Journals (Sweden)

    Guadalupe Gómez-Baena

    Full Text Available The marine cyanobacteria Prochlorococcus have been considered photoautotrophic microorganisms, although the utilization of exogenous sugars has never been specifically addressed in them. We studied glucose uptake in different high irradiance- and low irradiance-adapted Prochlorococcus strains, as well as the effect of glucose addition on the expression of several glucose-related genes. Glucose uptake was measured by adding radiolabelled glucose to Prochlorococcus cultures, followed by flow cytometry coupled with cell sorting in order to separate Prochlorococcus cells from bacterial contaminants. Sorted cells were recovered by filtration and their radioactivity measured. The expression, after glucose addition, of several genes (involved in glucose metabolism, and in nitrogen assimilation and its regulation was determined in the low irradiance-adapted Prochlorococcus SS120 strain by semi-quantitative real time RT-PCR, using the rnpB gene as internal control. Our results demonstrate for the first time that the Prochlorococcus strains studied in this work take up glucose at significant rates even at concentrations close to those found in the oceans, and also exclude the possibility of this uptake being carried out by eventual bacterial contaminants, since only Prochlorococcus cells were used for radioactivity measurements. Besides, we show that the expression of a number of genes involved in glucose utilization (namely zwf, gnd and dld, encoding glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and lactate dehydrogenase, respectively is strongly increased upon glucose addition to cultures of the SS120 strain. This fact, taken together with the magnitude of the glucose uptake, clearly indicates the physiological importance of the phenomenon. Given the significant contribution of Prochlorococcus to the global primary production, these findings have strong implications for the understanding of the phytoplankton role in the carbon

  2. Kinetics of glucose transport in rat muscle

    DEFF Research Database (Denmark)

    Ploug, Thorkil; Galbo, Henrik; Vinten, Jørgen

    1987-01-01

    The effects of insulin and prior muscle contractions, respectively, on 3-O-methylglucose (3-O-MG) transport in skeletal muscle were studied in the perfused rat hindquarter. Initial rates of entry of 3-O-MG in red gastrocnemius, soleus, and white gastrocnemius muscles as a function of perfusate 3-O...

  3. Impairment of brain endothelial glucose transporter by methamphetamine causes blood-brain barrier dysfunction

    Directory of Open Access Journals (Sweden)

    Murrin L Charles

    2011-03-01

    Full Text Available Abstract Background Methamphetamine (METH, an addictive psycho-stimulant drug with euphoric effect is known to cause neurotoxicity due to oxidative stress, dopamine accumulation and glial cell activation. Here we hypothesized that METH-induced interference of glucose uptake and transport at the endothelium can disrupt the energy requirement of the blood-brain barrier (BBB function and integrity. We undertake this study because there is no report of METH effects on glucose uptake and transport across the blood-brain barrier (BBB to date. Results In this study, we demonstrate that METH-induced disruption of glucose uptake by endothelium lead to BBB dysfunction. Our data indicate that a low concentration of METH (20 μM increased the expression of glucose transporter protein-1 (GLUT1 in primary human brain endothelial cell (hBEC, main component of BBB without affecting the glucose uptake. A high concentration of 200 μM of METH decreased both the glucose uptake and GLUT1 protein levels in hBEC culture. Transcription process appeared to regulate the changes in METH-induced GLUT1 expression. METH-induced decrease in GLUT1 protein level was associated with reduction in BBB tight junction protein occludin and zonula occludens-1. Functional assessment of the trans-endothelial electrical resistance of the cell monolayers and permeability of dye tracers in animal model validated the pharmacokinetics and molecular findings that inhibition of glucose uptake by GLUT1 inhibitor cytochalasin B (CB aggravated the METH-induced disruption of the BBB integrity. Application of acetyl-L-carnitine suppressed the effects of METH on glucose uptake and BBB function. Conclusion Our findings suggest that impairment of GLUT1 at the brain endothelium by METH may contribute to energy-associated disruption of tight junction assembly and loss of BBB integrity.

  4. Proposed Regulation of Gene Expression by Glucose in Rodent Heart

    Directory of Open Access Journals (Sweden)

    Martin E. Young

    2007-01-01

    Full Text Available Background: During pressure overload-induced hypertrophy, unloading-induced atrophy, and diabetes mellitus, the heart induces ‘fetal’ genes (e.g. myosin heavy chain β; mhcβ.Hypothesis: We propose that altered glucose homeostasis within the cardiomyocyte acts as a central mechanism for the regulation of gene expression in response to environmental stresses. The evidence is as follows. Methods and Results: Forced glucose uptake both ex vivo and in vivo results in mhc isoform switching. Restricting dietary glucose prevents mhc isoform switching in hearts of both GLUT1-Tg mice and rats subjected to pressure overload-induced hypertrophy. Thus, glucose availability correlates with mhc isoform switching under all conditions investigated. A potential mechanism by which glucose affects gene expression is through O-linked glycosylation of specific transcription factors. Glutamine:fructose-6-phosphate amidotransferase (GFAT catalyzes the flux generating step in UDP-N-acetylglucosamine biosynthesis, the rate determining metabolite in protein glycosylation. Ascending aortic constriction increased intracellular levels of UDP-N-acetylglucosamine, and the expression of gfat2, but not gfat1, in the rat heart.Conclusions: Collectively, the results strongly suggest glucose-regulated gene expression in the heart, and the involvement of glucose metabolites in isoform switching of sarcomeric proteins characteristic for the fetal gene program.

  5. Glucose transporter-1 (GLUT-1) immunoreactivity in benign, premalignant and malignant lesions of the gallbladder.

    Science.gov (United States)

    Legan, Mateja; Tevžič, Spela; Tolar, Ana; Luzar, Boštjan; Marolt, Vera Ferlan

    2011-03-01

    GLUT-1 is a transmembrane glucose transport protein that allows the facilitated transport of glucose into cells, normally expressed in tissues which depend mainly on glucose metabolism. Enhanced expression of GLUT-1 can also be found in a large spectrum of carcinomas. This study aimed to investigate GLUT-1 expression in gallbladder tissue: from normal tissue samples, hyperplasias, low-grade and high-grade dysplasias to gallbladder carcinomas. In all, 115 archived samples of gallbladder tissue from 68 patients, presented after cholecystectomy, were immunohistochemically stained for GLUT-1. According to the intensity of GLUT-1 immunoreactivity, samples were divided into negative (stained 0-10% of cells stained), positive with weak to moderate (10-50%) and positive with strong (>50%) GLUT-1 expression. The GLUT-1 immunoreactivity of the samples showed a characteristic increase from premalignant lesions to carcinomas. Normal gallbladder tissue samples did not express GLUT-1 (100%). Weak expression was shown only focally in hyperplasias, but to a greater extent with low-grade dysplasias (20%), high-grade dysplasias (40%) and carcinomas (51.8%). Normal gallbladder tissue is GLUT-1 negative. GLUT-1 expression in carcinoma tissue is significantly higher than in dysplastic lesions. Strong GLUT-1 expression indicates 100% specificity for detecting gallbladder carcinomas. Therefore, GLUT-1 is a candidate as a diagnostic as well as a tissue prognostic marker in gallbladder carcinoma patients.

  6. The impact of prolonged hyperinsulinaemia on glucose transport in equine skeletal muscle and digital lamellae.

    Science.gov (United States)

    de Laat, M A; Clement, C K; Sillence, M N; McGowan, C M; Pollitt, C C; Lacombe, V A

    2015-07-01

    An increased incidence of metabolic disease in horses has led to heightened recognition of the pathological consequences of insulin resistance. Laminitis, failure of the weightbearing digital lamellae, is an important consequence. Altered trafficking of specialised glucose transporters (GLUTs), responsible for glucose uptake, is central to the dysregulation of glucose metabolism and may play a role in the pathophysiology of laminitis. We hypothesised that prolonged hyperinsulinaemia alters the regulation of glucose transport in insulin-sensitive tissue and digital lamellae. Our objectives were to compare the relative protein expression of major GLUT isoforms in striated muscle and digital lamellae in healthy horses and during marked and moderate hyperinsulinaemia. Randomised, controlled study. Prolonged hyperinsulinaemia and lamellar damage were induced by a prolonged euglycaemic-hyperinsulinaemic clamp or a prolonged glucose infusion, and results were compared with those of electrolyte-treated control animals. Protein expression of GLUTs was examined with immunoblotting. Lamellar tissue contained more GLUT1 protein than skeletal muscle (P = 0.002) and less GLUT4 than the heart (P = 0.037). During marked hyperinsulinaemia and acute laminitis (induced by the prolonged euglycaemic-hyperinsulinaemic clamp), GLUT1 protein expression was decreased in skeletal muscle (P = 0.029) but unchanged in the lamellae, while novel GLUTs (8 and 12) were increased in the lamellae (P = 0.03) but not in skeletal muscle. However, moderate hyperinsulinaemia and subclinical laminitis (induced by the prolonged glucose infusion) did not cause differential GLUT protein expression in the lamellae compared with control horses. The results suggest that lamellar tissue functions independently of insulin and that insulin resistance may not be an essential component of the aetiology of laminitis. Marked differences in GLUT expression exist between insulin-sensitive and insulin-independent tissues

  7. Topography of brain glucose hypometabolism and epileptic network in glucose transporter 1 deficiency.

    Science.gov (United States)

    Akman, Cigdem Inan; Provenzano, Frank; Wang, Dong; Engelstad, Kristin; Hinton, Veronica; Yu, Julia; Tikofsky, Ronald; Ichese, Masonari; De Vivo, Darryl C

    2015-02-01

    (18)F fluorodeoxyglucose positron emission tomography ((18)F FDG-PET) facilitates examination of glucose metabolism. Previously, we described regional cerebral glucose hypometabolism using (18)F FDG-PET in patients with Glucose transporter 1 Deficiency Syndrome (Glut1 DS). We now expand this observation in Glut1 DS using quantitative image analysis to identify the epileptic network based on the regional distribution of glucose hypometabolism. (18)F FDG-PET scans of 16 Glut1 DS patients and 7 healthy participants were examined using Statistical parametric Mapping (SPM). Summed images were preprocessed for statistical analysis using MATLAB 7.1 and SPM 2 software. Region of interest (ROI) analysis was performed to validate SPM results. Visual analysis of the (18)F FDG-PET images demonstrated prominent regional glucose hypometabolism in the thalamus, neocortical regions and cerebellum bilaterally. Group comparison using SPM analysis confirmed that the regional distribution of glucose hypo-metabolism was present in thalamus, cerebellum, temporal cortex and central lobule. Two mildly affected patients without epilepsy had hypometabolism in cerebellum, inferior frontal cortex, and temporal lobe, but not thalamus. Glucose hypometabolism did not correlate with age at the time of PET imaging, head circumference, CSF glucose concentration at the time of diagnosis, RBC glucose uptake, or CNS score. Quantitative analysis of (18)F FDG-PET imaging in Glut1 DS patients confirmed that hypometabolism was present symmetrically in thalamus, cerebellum, frontal and temporal cortex. The hypometabolism in thalamus correlated with the clinical history of epilepsy. Copyright © 2014. Published by Elsevier B.V.

  8. Suppression of facilitative glucose transporter 1 mRNA can suppress tumor growth.

    Science.gov (United States)

    Noguchi, Y; Saito, A; Miyagi, Y; Yamanaka, S; Marat, D; Doi, C; Yoshikawa, T; Tsuburaya, A; Ito, T; Satoh, S

    2000-06-30

    We attempted to suppress glucose transporter 1 (GLUT1) expression by transfecting MKN45 cells with cDNA for antisense GLUT1. Glucose transport was significantly decreased in cells with antisense GLUT1 compared with wild-type cells or cells with vector alone. Suppression of GLUT1 mRNA resulted in a decreased number of cells in the S phase. This was accompanied by overexpression of p21 protein. Tumorigenicity in the nude mice injected with antisense GLUT1 expressing cells was significantly slower than in those with wild-type MKN45 cells. These results suggest that antisense GLUT1 mRNA inhibits tumor growth through a G(1) arrest and that expression of antisense GLUT1 mRNA via gene therapy can be used as a tool in the treatment of cancer.

  9. N-Methyl-D aspartate receptor-mediated effect on glucose transporter-3 levels of high glucose exposed-SH-SY5Y dopaminergic neurons.

    Science.gov (United States)

    Engin, Ayse Basak; Engin, Evren Doruk; Karakus, Resul; Aral, Arzu; Gulbahar, Ozlem; Engin, Atilla

    2017-11-01

    High glucose and insulin lead to neuronal insulin resistance. Glucose transport into the neurons is achieved by regulatory induction of surface glucose transporter-3 (GLUT3) instead of the insulin. N-methyl-D aspartate (NMDA) receptor activity increases GLUT3 expression. This study explored whether an endogenous NMDA receptor antagonist, kynurenic acid (KynA) affects the neuronal cell viability at high glucose concentrations. SH-SY5Y neuroblastoma cells were exposed to 150-250 mg/dL glucose and 40 μU/mL insulin. In KynA and N-nitro-l-arginine methyl ester (L-NAME) supplemented cultures, oxidative stress, mitochondrial metabolic activity (MTT), nitric oxide as nitrite+nitrate (NOx) and GLUT3 were determined at the end of 24 and 48-h incubation periods. Viable cells were counted by trypan blue dye. High glucose-exposed SH-SY5Y cells showed two-times more GLUT3 expression at second 24-h period. While GLUT3-stimulated glucose transport and oxidative stress was increased, total mitochondrial metabolic activity was significantly reduced. Insulin supplementation to high glucose decreased NOx synthesis and GLUT3 levels, in contrast oxidative stress increased three-fold. KynA significantly reduced oxidative stress, and increased MTT by regulating NOx production and GLUT3 expression. KynA is a noteworthy compound, as an endogenous, specific NMDA receptor antagonist; it significantly reduces oxidative stress, while increasing cell viability at high glucose and insulin concentrations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Renal and intestinal hexose transport in familial glucose-galactose malabsorption

    Science.gov (United States)

    Elsas, Louis J.; Hillman, Richard E.; Patterson, Joseph H.; Rosenberg, Leon E.

    1970-01-01

    Glucose transport by jejunal mucosa in vitro and kidney in vivo was investigated in a 3 yr old patient with congenital glucose-galactose malabsorption, her family, and 16 normal volunteers. Glucose transport by normal human jejunal mucosa was concentrative, saturable, sodium and energy dependent, and exhibited competitive inhibition. Biopsy specimens from six normal controls and an asymptomatic 5 yr old brother of the proband accumulated glucose to concentrations 16 times that in the incubation medium. The proband's mucosa was unable to concentrate glucose throughout a 60 min incubation period. Both of her parents and a half sister demonstrated impaired glucose transport. Their values fell between normal and those of the proband. Influx of glucose was impaired but efflux of glucose from the mucosa of these three heterozygotes was identical with that in three normal controls. A kinetic analysis indicated a reduced capacity (Vmax), but a normal affinity (Km) for glucose transport by their intestinal mucosa. All subjects accumulated fructose similarly. Renal glucose transport was investigated using renal glucose titration techniques. A partial defect in renal glucose reabsorption was found in the proband. Her brother's titration curve was similar to that of seven normal volunteers. We conclude that familial glucose-galactose malabsorption is inherited as an autosomal recessive trait, that heterozygotes for this disorder are detectable and demonstrate a reduced capacity for glucose transport, and that absent intestinal glucose transport is accompanied by partial impairment of renal glucose transport. Images PMID:5415683

  11. Role of the AMPKgamma3 isoform in hypoxia-stimulated glucose transport in glycolytic skeletal muscle

    DEFF Research Database (Denmark)

    Deshmukh, Atul S; Glund, Stephan; Tom, Robby Z

    2009-01-01

    in hypoxia-mediated energy status signaling and glucose transport in fast-twitch glycolytic extensor digitorum longus (EDL) muscle from AMPKgamma3-knockout (KO) mice and wild-type mice. Although hypoxia increased glucose transport (P

  12. Glucose Regulates the Expression of the Apolipoprotein A5 Gene

    Energy Technology Data Exchange (ETDEWEB)

    Fruchart, Jamila; Nowak, Maxime; Helleboid-Chapman, Audrey; Jakel, Heidelinde; Moitrot, Emmanuelle; Rommens, Corinne; Pennacchio, Len A.; Fruchart-Najib, Jamila; Fruchart, Jean-Charles

    2008-04-07

    The apolipoprotein A5 gene (APOA5) is a key player in determining triglyceride concentrations in humans and mice. Since diabetes is often associated with hypertriglyceridemia, this study explores whether APOA5 gene expression is regulated by alteration in glucose homeostasis and the related pathways. D-glucose activates APOA5 gene expression in a time- and dose-dependent manner in hepatocytes, and the glycolytic pathway involved was determined using D-glucose analogs and metabolites. Together, transient transfections, electrophoretic mobility shift assays and chromatin immunoprecipitation assays show that this regulation occurs at the transcriptional level through an increase of USF1/2 binding to an E-box in the APOA5 promoter. We show that this phenomenon is not due to an increase of mRNA or protein expression levels of USF. Using protein phosphatases 1 and 2A inhibitor, we demonstrate that D-glucose regulates APOA5 gene via a dephosphorylation mechanism, thereby resulting in an enhanced USF1/2-promoter binding. Last, subsequent suppressions of USF1/2 and phosphatases mRNA through siRNA gene silencing abolished the regulation. We demonstrate that APOA5 gene is up regulated by D-glucose and USF through phosphatase activation. These findings may provide a new cross talk between glucose and lipid metabolism.

  13. Experimental type II diabetes and related models of impaired glucose metabolism differentially regulate glucose transporters at the proximal tubule brush border membrane.

    Science.gov (United States)

    Chichger, Havovi; Cleasby, Mark E; Srai, Surjit K; Unwin, Robert J; Debnam, Edward S; Marks, Joanne

    2016-06-01

    What is the central question of this study? Although SGLT2 inhibitors represent a promising treatment for patients suffering from diabetic nephropathy, the influence of metabolic disruption on the expression and function of glucose transporters is largely unknown. What is the main finding and its importance? In vivo models of metabolic disruption (Goto-Kakizaki type II diabetic rat and junk-food diet) demonstrate increased expression of SGLT1, SGLT2 and GLUT2 in the proximal tubule brush border. In the type II diabetic model, this is accompanied by increased SGLT- and GLUT-mediated glucose uptake. A fasted model of metabolic disruption (high-fat diet) demonstrated increased GLUT2 expression only. The differential alterations of glucose transporters in response to varying metabolic stress offer insight into the therapeutic value of inhibitors. SGLT2 inhibitors are now in clinical use to reduce hyperglycaemia in type II diabetes. However, renal glucose reabsorption across the brush border membrane (BBM) is not completely understood in diabetes. Increased consumption of a Western diet is strongly linked to type II diabetes. This study aimed to investigate the adaptations that occur in renal glucose transporters in response to experimental models of diet-induced insulin resistance. The study used Goto-Kakizaki type II diabetic rats and normal rats rendered insulin resistant using junk-food or high-fat diets. Levels of protein kinase C-βI (PKC-βI), GLUT2, SGLT1 and SGLT2 were determined by Western blotting of purified renal BBM. GLUT- and SGLT-mediated d-[(3) H]glucose uptake by BBM vesicles was measured in the presence and absence of the SGLT inhibitor phlorizin. GLUT- and SGLT-mediated glucose transport was elevated in type II diabetic rats, accompanied by increased expression of GLUT2, its upstream regulator PKC-βI and SGLT1 protein. Junk-food and high-fat diet feeding also caused higher membrane expression of GLUT2 and its upstream regulator PKC

  14. [Glucose transporter protein type 1 (GLUT-1) deficiency syndrome].

    Science.gov (United States)

    Ramm-Pettersen, Anette; Selmer, Kaja Kristine; Nakken, Karl O

    2011-05-06

    Glucose is the brain's main source of energy. To pass the blood-brain barrier, glucose transporter protein type 1 (GLUT-1) is essential. Mutations in the SLC2A1 gene which codes for GLUT-1 may therefore compromise the supply of glucose to the brain. The aim of this review is to describe the clinical consequences of such mutations, with special emphasis on GLUT-1 encephalopathy. This review is based on a non-systematic literature search in PubMed and the authors' experience within the field. Epileptic or epilepsy-like are usually the first symptom in children with the GLUT-1 deficiency syndrome. Later on these children suffer delayed psychomotor development, microcephaly, ataxia, spasticity or movement disorders. EEG abnormalities may develop. GLUT-1 deficiency syndrome should be suspected in children with epilepsy-like seizures and delayed development combined with a low content of glucose in spinal fluid. The diagnosis is confirmed by genetic testing. Treatment is a ketogenic diet, as ketone bodies pass the blood-brain barrier using other transport proteins than GLUT-1. GLUT-1-deficiency syndrome is a rare metabolic encephalopathy which is not well known and probably underdiagnosed. An early diagnosis and early start of a ketogenic diet may give these children a normal or nearly normal life.

  15. Glucose transport by epithelia prepared from harvested enterocytes

    DEFF Research Database (Denmark)

    Kimura, Yasuhiro; van der Merwe, Marie; Bering, Stine Brandt

    2015-01-01

    of epithelial function and was demonstrated by cellular accumulation of tracer (14)C D-glucose and Ussing chamber based short-circuit currents. Assessment of the epithelia by light and immunofluorescent microscopy revealed the harvested enterocytes remain differentiated and establish cell-cell connections...... transporter SGLT-1. Similarly, accumulation of (14)C D-glucose by the epithelia was inhibited by phloridzin, but not phloretin, and was stimulated by pre-exposure to AMP and adenosine, apparently by a microtubule-based mechanism that is disrupted by nocodazole, with the magnitudes of responses to adenosine......, forskolin, and health status exceeding those we have measured using intact tissues. Our findings indicate that epithelia prepared from harvested enterocytes provide an alternative approach for comparative studies of the characteristics of nutrient transport by the upper villus epithelium and the responses...

  16. Glucose transporter-1 as an independent prognostic marker for cancer: a meta-analysis

    Science.gov (United States)

    Zhao, Zheng-Xiao; Lu, Lin-Wei; Qiu, Jian; Li, Qiu-Ping; Xu, Fei; Liu, Bao-Jun; Dong, Jing-Cheng; Gong, Wei-Yi

    2018-01-01

    Objective Glucose transporter-1 (GLUT-1) as the major glucose transporter present in human cells is found overexpressed in a proportion of human malignancies. This meta-analysis is attempted to assess the prognostic significance of GLUT-1 for survival in various cancers. Materials and Methods We conducted an electronic search using the databases PubMed, Embase and Web of Science, from inception to Oct 20th, 2016. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. Results Fourty-one studies with a total of 4794 patients were included. High GLUT-1 expression was significantly associated with poorer prognosis [overall survival: HR = 1.833 (95% CI: 1.597–2.069, P GLUT-1 expression may be an independent prognostic marker to predict poor survival in various types of cancers. Further clinical trials with high quality need to be conducted to confirm our conclusion. PMID:29416806

  17. Glucose transporter 1-mediated glucose uptake is limiting for B-cell acute lymphoblastic leukemia anabolic metabolism and resistance to apoptosis.

    Science.gov (United States)

    Liu, T; Kishton, R J; Macintyre, A N; Gerriets, V A; Xiang, H; Liu, X; Abel, E D; Rizzieri, D; Locasale, J W; Rathmell, J C

    2014-10-16

    The metabolic profiles of cancer cells have long been acknowledged to be altered and to provide new therapeutic opportunities. In particular, a wide range of both solid and liquid tumors use aerobic glycolysis to supply energy and support cell growth. This metabolic program leads to high rates of glucose consumption through glycolysis with secretion of lactate even in the presence of oxygen. Identifying the limiting events in aerobic glycolysis and the response of cancer cells to metabolic inhibition is now essential to exploit this potential metabolic dependency. Here, we examine the role of glucose uptake and the glucose transporter Glut1 in the metabolism and metabolic stress response of BCR-Abl+ B-cell acute lymphoblastic leukemia cells (B-ALL). B-ALL cells were highly glycolytic and primary human B-ALL samples were dependent on glycolysis. We show B-ALL cells express multiple glucose transporters and conditional genetic deletion of Glut1 led to a partial loss of glucose uptake. This reduced glucose transport capacity, however, was sufficient to metabolically reprogram B-ALL cells to decrease anabolic and increase catabolic flux. Cell proliferation decreased and a limited degree of apoptosis was also observed. Importantly, Glut1-deficient B-ALL cells failed to accumulate in vivo and leukemic progression was suppressed by Glut1 deletion. Similarly, pharmacologic inhibition of aerobic glycolysis with moderate doses of 2-deoxyglucose (2-DG) slowed B-ALL cell proliferation, but extensive apoptosis only occurred at high doses. Nevertheless, 2-DG induced the pro-apoptotic protein Bim and sensitized B-ALL cells to the tyrosine kinase inhibitor Dasatinib in vivo. Together, these data show that despite expression of multiple glucose transporters, B-ALL cells are reliant on Glut1 to maintain aerobic glycolysis and anabolic metabolism. Further, partial inhibition of glucose metabolism is sufficient to sensitize cancer cells to specifically targeted therapies, suggesting

  18. Overexpression of glucose transporter-1 (GLUT-1) predicts poor prognosis in epithelial ovarian cancer.

    Science.gov (United States)

    Cho, Hanbyoul; Lee, You Sun; Kim, Julie; Chung, Joon-Yong; Kim, Jae-Hoon

    2013-11-01

    Illumina microarray was used to identify differentially expressed genes in three epithelial ovarian cancer (EOC) cells. To validate the microarray data, mRNA and protein level of glucose transporter-1 (GLUT-1) was examined. GLUT-1 had an EOC/normal cells ratio of 5.51 based on microarray. Real-time PCR and immunohistochemistry demonstrated that GLUT-1 expression was significantly increased in EOC (p = .029 and p GLUT-1 overexpression (HR = 4.80, p = .027) and lymph node metastases (HR = 8.35, p = .016) conferred a significantly worse overall survival. In conclusion, GLUT-1 expression is remarkably upregulated in EOC and predicts a poor overall survival.

  19. Duodenal Sodium/Glucose Cotransporter 1 Expression Under Fasting Conditions Is Associated With Postload Hyperglycemia.

    Science.gov (United States)

    Fiorentino, Teresa Vanessa; Suraci, Evelina; Arcidiacono, Gaetano Paride; Cimellaro, Antonio; Mignogna, Chiara; Presta, Ivan; Andreozzi, Francesco; Hribal, Marta Letizia; Perticone, Francesco; Donato, Giuseppe; Luzza, Francesco; Sesti, Giorgio

    2017-11-01

    Type 2 diabetes (T2DM) is associated with a higher intestinal expression of the glucose transporters sodium/glucose cotransporter 1 (SGLT-1) and glucose transporter 2 (GLUT-2). It is currently unsettled whether prediabetes conditions characterized by postprandial hyperglycemia, such as impaired glucose tolerance (IGT) and normal glucose tolerance (NGT) with 1-hour postload glucose ≥155 mg/dL (8.6 mmol/L) (NGT-1h-high) are associated with increased expression of these glucose carriers in the intestine. We evaluated whether duodenal abundance of SGLT-1 and GLUT-2 is augmented in subjects with IGT and NGT-1h-high, in comparison with subjects with NGT and 1-hour postload glucose ˂155 mg/dL (NGT-1h-low). Cross-sectional. A total of 54 individuals underwent an upper gastrointestinal endoscopy. Duodenal SGLT-1 and GLUT-2 protein and messenger RNA levels were assessed by Western blot and reverse transcription polymerase chain reaction, respectively. Of the 54 subjects examined, 18 had NGT-1h-low, 12 had NGT-1h-high, 12 had IGT, and 12 had T2DM. Duodenal SGLT-1 protein and messenger RNA levels were significantly higher in individuals with NGT-1h-high, IGT, or T2DM in comparison with NGT-1h-low subjects. GLUT-2 abundance was higher in individuals with T2DM in comparison with NGT-1h-low subjects; no substantial increase in GLUT-2 expression was observed in NGT-1h-high or IGT individuals. Univariate correlations showed that duodenal SGLT-1 abundance was positively correlated with 1-hour postload plasma glucose levels (r = 0.44; P = 0.003) but not with fasting or 2-hour postload glucose levels. Duodenal SGLT-1 expression is increased in individuals with 1-hour postload hyperglycemia or IGT, as well as in subjects with T2DM, and it positively correlates with early postload glucose excursion. Copyright © 2017 Endocrine Society

  20. Molecular Dynamics Simulations of the Human Glucose Transporter GLUT1.

    Directory of Open Access Journals (Sweden)

    Min-Sun Park

    Full Text Available Glucose transporters (GLUTs provide a pathway for glucose transport across membranes. Human GLUTs are implicated in devastating diseases such as heart disease, hyper- and hypo-glycemia, type 2 diabetes and cancer. The human GLUT1 has been recently crystalized in the inward-facing open conformation. However, there is no other structural information for other conformations. The X-ray structures of E. coli Xylose permease (XylE, a glucose transporter homolog, are available in multiple conformations with and without the substrates D-xylose and D-glucose. XylE has high sequence homology to human GLUT1 and key residues in the sugar-binding pocket are conserved. Here we construct a homology model for human GLUT1 based on the available XylE crystal structure in the partially occluded outward-facing conformation. A long unbiased all atom molecular dynamics simulation starting from the model can capture a new fully opened outward-facing conformation. Our investigation of molecular interactions at the interface between the transmembrane (TM domains and the intracellular helices (ICH domain in the outward- and inward-facing conformation supports that the ICH domain likely stabilizes the outward-facing conformation in GLUT1. Furthermore, inducing a conformational transition, our simulations manifest a global asymmetric rocker switch motion and detailed molecular interactions between the substrate and residues through the water-filled selective pore along a pathway from the extracellular to the intracellular side. The results presented here are consistent with previously published biochemical, mutagenesis and functional studies. Together, this study shed light on the structure and functional relationships of GLUT1 in multiple conformational states.

  1. Brain Transport Profiles of Ginsenoside Rb1 by Glucose Transporter 1: In Vitro and in Vivo

    Directory of Open Access Journals (Sweden)

    Yu-Zhu Wang

    2018-04-01

    Full Text Available Ginsenoside Rb1 (Rb1 has been demonstrated its protection for central nervous system and is apparently highly distributed to the brain. The objective of this study was to characterize Rb1 transport at the blood–brain barrier (BBB using primary cultured rat brain microvascular endothelial cells (rBMEC, an in vitro BBB model. The initial uptake velocity of Rb1 in rBMEC was temperature- and concentration-dependent, and was significantly reduced by phloretin, an inhibitor of GLUT1 transporter, but was independent of metabolic inhibitor. Furthermore, the transport of Rb1 into rBMEC was significantly diminished in the presence of natural substrate α-D-glucose, suggesting a facilitated transport of Rb1 via GLUT1 transporter. The impact of GLUT1 on the distribution of Rb1 between brain and plasma was studied experimentally in rats. Administration of phloretin (5 mg/kg, i.v. to normal rats for consecutive 1 week before Rb1 (10 mg/kg, i.v. at 0.5, 2, and 6 h did not alter Rb1 concentrations in plasma, but resulted in significant decreased brain concentrations of Rb1 compared to in the phloretin-untreated normal rats (489.6 ± 58.3 versus 105.1 ± 15.1 ng/g, 193.8 ± 11.1 versus 84.8 ± 4.1 ng/g, and 114.2 ± 24.0 versus 39.9 ± 4.9 ng/g, respectively. The expression of GLUT1 in the phloretin-treated group by western blotting analysis in vitro and in vivo experiments was significantly decreased, indicating that the decreased transport of Rb1 in brain was well related to the down-regulated function and level of GLUT1. Therefore, our in vitro and in vivo results indicate that the transport of Rb1 at the BBB is at least partly mediated by GLUT1 transporter.

  2. Experimental type II diabetes and related models of impaired glucose metabolism differentially regulate glucose transporters at the proximal tubule brush border membrane

    OpenAIRE

    Chichger, H.; Cleasby, M.; Srai, S.; Unwin, R.; Debnam, E.; Marks, J.

    2016-01-01

    What is the central question of this study? Although SGLT2 inhibitors represent a promising treatment for patients suffering from diabetic nephropathy, the influence of metabolic disruption on the expression and function of glucose transporters is largely unknown. What is the main finding and its importance? In vivo models of metabolic disruption (Goto-Kakizaki type II diabetic rat and junk-food diet) demonstrate increased expression of SGLT1, SGLT2 and GLUT2 in the proximal tubule brush bord...

  3. Insulin modulates hippocampally-mediated spatial working memory via glucose transporter-4.

    Science.gov (United States)

    Pearson-Leary, J; Jahagirdar, V; Sage, J; McNay, E C

    2018-02-15

    The insulin-regulated glucose transporter, GluT4, is a key molecule in peripheral insulin signaling. Although GluT4 is abundantly expressed in neurons of specific brain regions such as the hippocampus, the functional role of neuronal GluT4 is unclear. Here, we used pharmacological inhibition of GluT4-mediated glucose uptake to determine whether GluT4 mediates insulin-mediated glucose uptake in the hippocampus. Consistent with previous reports, we found that glucose utilization increased in the dorsal hippocampus of male rats during spontaneous alternation (SA), a hippocampally-mediated spatial working memory task. We previously showed that insulin signaling within the hippocampus is required for processing this task, and that administration of exogenous insulin enhances performance. At baseline levels of hippocampal insulin, inhibition of GluT4-mediated glucose uptake did not affect SA performance. However, inhibition of an upstream regulator of GluT4, Akt, did impair SA performance. Conversely, when a memory-enhancing dose of insulin was delivered to the hippocampus prior to SA-testing, inhibition of GluT4-mediated glucose transport prevented cognitive enhancement. These data suggest that baseline hippocampal cognitive processing does not require functional hippocampal GluT4, but that cognitive enhancement by supra-baseline insulin does. Consistent with these findings, we found that in neuronal cell culture, insulin increases glucose utilization in a GluT4-dependent manner. Collectively, these data demonstrate a key role for GluT4 in transducing the procognitive effects of elevated hippocampal insulin. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. MicroRNA Expression Varies according to Glucose Tolerance, Measurement Platform, and Biological Source

    Directory of Open Access Journals (Sweden)

    S. Dias

    2017-01-01

    Full Text Available Dysregulated microRNA (miRNA expression is observed during type 2 diabetes (T2D, although the consistency of miRNA expression across measurement platform and biological source is uncertain. Here we report miRNA profiling in the whole blood and serum of South African women with different levels of glucose tolerance, using next generation sequencing (NGS and quantitative real time PCR (qRT-PCR. Whole blood-derived miRNAs from women with newly diagnosed T2D (n=4, impaired glucose tolerance (IGT (n=4, and normal glucose tolerance (NGT (n=4 were subjected to NGS, whereafter transcript levels of selected miRNAs were quantified in the whole blood and serum of these women using qRT-PCR. Of the five significantly differentially expressed miRNAs identified by NGS, only the directional increase of miR-27b in women with IGT compared to NGT was confirmed in whole blood and serum, using qRT-PCR. Functional enrichment of miR-27b gene targets identified biological pathways associated with glucose transport and insulin regulation. In conclusion, this study showed poor correlation in miRNA expression profiled using NGS and qRT-PCR and in whole blood and serum. The consistent increased expression of miR-27b in women with IGT compared to NGT across measurement platform and biological source holds potential as a biomarker for risk stratification in our population.

  5. Facilitated transport of glucose from blood to brain in man and the effect of moderate hypoglycaemia on cerebral glucose utilization

    International Nuclear Information System (INIS)

    Blomqvist, G.; Widen, L.; Hellstrand, E.; Gutniak, M.; Grill, V.

    1991-01-01

    The effect of steady-state moderate hypoglycaemia on human brain homeostasis has been studied with positron emission tomography using D-glucose 11 C(ul) as tracer. To rule out any effects of insulin, the plasma insulin concentration was maintained at the same level under normo- and hypoglycaemic conditions. Reduction of blood glucose by 55% increased the glucose clearance through the blood-brain barrier by 50% and reduced brain glucose consumption by 40%. Blood flow was not affected. The results are consistent with facilitated transport of glucose from blood to brain in humans. The maximal transport rate of glucose from blood to brain was found to be 62±19 (mean±SEM) μmol hg -1 min -1 , and the half-saturation constant was found to be 4.1±3.2 mM. (orig.)

  6. Sodium glucose transporter 2 (SGLT2 inhibition and ketogenesis

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2015-01-01

    Full Text Available Sodium glucose transporter 2 (SGLT2 inhibitors are a recently developed class of drug that have been approved for use in type 2 diabetes. Their unique extra-pancreatic glucuretic mode of action has encouraged their usage in type 1 diabetes as well. At the same time, reports of pseudo ketoacidosis and ketoacidosis related to their use have been published. No clear mechanism for this phenomenon has been demonstrated so far. This communication delves into the biochemical effects of SGLT2 inhibition, discusses the utility of these drugs and proposes steps to maximize safe usage of the molecules.

  7. Sodium glucose transporter 2 (SGLT2) inhibition and ketogenesis.

    Science.gov (United States)

    Kalra, Sanjay; Sahay, Rakesh; Gupta, Yashdeep

    2015-01-01

    Sodium glucose transporter 2 (SGLT2) inhibitors are a recently developed class of drug that have been approved for use in type 2 diabetes. Their unique extra-pancreatic glucuretic mode of action has encouraged their usage in type 1 diabetes as well. At the same time, reports of pseudo ketoacidosis and ketoacidosis related to their use have been published. No clear mechanism for this phenomenon has been demonstrated so far. This communication delves into the biochemical effects of SGLT2 inhibition, discusses the utility of these drugs and proposes steps to maximize safe usage of the molecules.

  8. Steviol Glycosides Modulate Glucose Transport in Different Cell Types

    Science.gov (United States)

    Rizzo, Benedetta; Zambonin, Laura; Leoncini, Emanuela; Vieceli Dalla Sega, Francesco; Prata, Cecilia; Fiorentini, Diana; Hrelia, Silvana

    2013-01-01

    Extracts from Stevia rebaudiana Bertoni, a plant native to Central and South America, have been used as a sweetener since ancient times. Currently, Stevia extracts are largely used as a noncaloric high-potency biosweetener alternative to sugar, due to the growing incidence of type 2 diabetes mellitus, obesity, and metabolic disorders worldwide. Despite the large number of studies on Stevia and steviol glycosides in vivo, little is reported concerning the cellular and molecular mechanisms underpinning the beneficial effects on human health. The effect of four commercial Stevia extracts on glucose transport activity was evaluated in HL-60 human leukaemia and in SH-SY5Y human neuroblastoma cells. The extracts were able to enhance glucose uptake in both cellular lines, as efficiently as insulin. Our data suggest that steviol glycosides could act by modulating GLUT translocation through the PI3K/Akt pathway since treatments with both insulin and Stevia extracts increased the phosphorylation of PI3K and Akt. Furthermore, Stevia extracts were able to revert the effect of the reduction of glucose uptake caused by methylglyoxal, an inhibitor of the insulin receptor/PI3K/Akt pathway. These results corroborate the hypothesis that Stevia extracts could mimic insulin effects modulating PI3K/Akt pathway. PMID:24327825

  9. Effect of erythropoietin on the glucose transport of rat erythrocytes and bone marrow cells

    International Nuclear Information System (INIS)

    Ghosal, J.; Chakraborty, M.; Biswas, T.; Ganguly, C.K.; Datta, A.G.

    1987-01-01

    The effect of Ep on radioactive glucose and methyl-alpha-D-glucoside transport by rat erythrocytes and bone marrow cells were studied. There is initial linearity followed by saturation kinetics of [ 14 C]glucose transport by the erythrocytes of starved and starved plus Ep-treated rats at different concentrations of glucose. Starvation caused slight inhibition of glucose transport which increased markedly on Ep administration to starved rats. Normal animals failed to show any significant change in glucose transport after Ep treatment. Methyl-alpha-D-glucoside inhibited the Ep-stimulated glucose transport significantly. Ep also stimulated the transport of radioactive methyl-alpha-D-glucoside which was competitively inhibited in presence of D-glucose. Glucose transport in erythrocytes was found to be sensitive to metabolic inhibitors like azide and DNP. A sulfhydryl reagent and ouabain also inhibited the transport process. Ep stimulated glucose and methyl-alpha-D-glucoside transport in the bone marrow cells of starved rats. The sugar analog competitively inhibited the glucose transport in bone marrow cells and vice versa

  10. Stimulation of Na+/K+ ATPase activity and Na+ coupled glucose transport by β-catenin

    International Nuclear Information System (INIS)

    Sopjani, Mentor; Alesutan, Ioana; Wilmes, Jan; Dermaku-Sopjani, Miribane; Lam, Rebecca S.; Koutsouki, Evgenia; Jakupi, Muharrem; Foeller, Michael; Lang, Florian

    2010-01-01

    Research highlights: → The oncogenic transcription factor β-catenin stimulates the Na + /K + -ATPase. → β-Catenin stimulates SGLT1 dependent Na + , glucose cotransport. → The effects are independent of transcription. → β-Catenin sensitive transport may contribute to properties of proliferating cells. -- Abstract: β-Catenin is a multifunctional protein stimulating as oncogenic transcription factor several genes important for cell proliferation. β-Catenin-regulated genes include the serum- and glucocorticoid-inducible kinase SGK1, which is known to stimulate a variety of transport systems. The present study explored the possibility that β-catenin influences membrane transport. To this end, β-catenin was expressed in Xenopus oocytes with or without SGLT1 and electrogenic transport determined by dual electrode voltage clamp. As a result, expression of β-catenin significantly enhanced the ouabain-sensitive current of the endogeneous Na + /K + -ATPase. Inhibition of vesicle trafficking by brefeldin A revealed that the stimulatory effect of β-catenin on the endogenous Na + /K + -ATPase was not due to enhanced stability of the pump protein in the cell membrane. Expression of β-catenin further enhanced glucose-induced current (Ig) in SGLT1-expressing oocytes. In the absence of SGLT1 Ig was negligible irrespective of β-catenin expression. The stimulating effect of β-catenin on both Na + /K + ATPase and SGLT1 activity was observed even in the presence of actinomycin D, an inhibitor of transcription. The experiments disclose a completely novel function of β-catenin, i.e. the regulation of transport.

  11. Isotonic transport by the Na+-glucose cotransporter SGLT1 from humans and rabbit

    DEFF Research Database (Denmark)

    Zeuthen, T; Meinild, A K; Loo, D D

    2001-01-01

    1. In order to study its role in steady state water transport, the Na+-glucose cotransporter (SGLT1) was expressed in Xenopus laevis oocytes; both the human and the rabbit clones were tested. The transport activity was monitored as a clamp current and the flux of water followed optically...... as the change in oocyte volume. 2. SGLT1 has two modes of water transport. First, it acts as a molecular water pump: for each 2 Na+ and 1 sugar molecule 264 water molecules were cotransported in the human SGLT1 (hSGLT1), 424 for the rabbit SGLT1 (rSGLT1). Second, it acts as a water channel. 3. The cotransport...... of water was tightly coupled to the sugar-induced clamp current. Instantaneous changes in clamp current induced by changes in clamp voltage were accompanied by instantaneous changes in the rate of water transport. 4. The cotransported solution was predicted to be hypertonic, and an osmotic gradient built...

  12. Taste and move: glucose and peptide transporters in the gastrointestinal tract.

    Science.gov (United States)

    Daniel, Hannelore; Zietek, Tamara

    2015-12-01

    What is the topic of this review? Nutrient absorption in the gastrointestinal tract requires membrane proteins embedded in the apical membrane of epithelial cells that allow bulk quantities of nutrients, such as monosaccharides and amino acids, to be moved into epithelial cells. Very recently, a new function of the transporters as nutrient sensors mediating peptide hormone release from enteroendocrine cells has been discovered. What advances does it highlight? The review covers recent advances in membrane transporter functions for the absorption and sensing of dietary peptides and sugars and their putative interplay. Nutrient transporters are integral membrane proteins responsible for uptake into enterocytes and release of nutrients into the circulation. Absorption of food breakdown products, such as fatty acids, monosaccharides or amino acids, requires high-capacity transporters. In the case of glucose, amino acids and peptides, the transporters are electrogenic in nature, coupling substrate flux to ion movement. While glucose absorption is mediated by the Na(+)-dependent SGLT1 protein, uptake of short-chain peptides is mediated by the H(+)-coupled PEPT1 protein. Interestingly, both transporters were recently shown to fulfil an additional role as intestinal 'sensors' in enteroendocrine cells, mediating the release of gastrointestinal peptide hormones into the circulation. Sensing of D-glucose and of di- and tripeptides is particularly relevant for the secretion of the incretins glucose-dependent insulinotrophic polypeptide and glucagon-like peptide 1 that promote insulin output from β-cells and mediate β-cell protection. In addition to these sensing pathways, a variety of G-protein-coupled receptors are involved in sensing of intestinal contents. D-Glucose is sensed not only by SGLT1 but also by the sweet taste receptor T1R2/3 expressed in enteroendocrine cells. Activation of T1R2/3 increases SGLT1 levels and intestinal glucose absorption. Although T1R2

  13. Glucose uptake and growth of glucose-limited chemostat cultures of Aspergillus niger and a disruptant lacking MstA, a high-affinity glucose transporter

    NARCIS (Netherlands)

    Jorgensen, T.R.; vanKuyk, P.A.; Poulsen, B.R.; Ruijter, G.J.G.; Visser, J.; Iversen, J.J.L.

    2007-01-01

    This is a study of high-affinity glucose uptake in Aspergillus niger and the effect of disruption of a high-affinity monosaccharide-transporter gene, mstA. The substrate saturation constant (K-s) of a reference strain was about 15 mu M in glucose-limited chemostat culture. Disruption of mstA

  14.  The role of glucose transporter 1 (GLUT1 in the diagnosis and therapy of tumors

    Directory of Open Access Journals (Sweden)

    Paweł Jóźwiak

    2012-03-01

    Full Text Available  Malignant cells are known to enhance glucose metabolism, to increase glucose uptake and to inhibit the process of oxidative phosphorylation. Accelerated glycolysis is one of the biochemical characteristics of cancer cells that allow them to compensate the inefficient extraction of energy from glucose in order to continue their uncontrolled growth and proliferation. Upregulation of glucose transport across the plasma membrane is mediated by a family of facilitated glucose transporter proteins named GLUT. Overexpression of GLUTs, especially the hypoxia-responsive GLUT1, has been frequently observed in various human carcinomas. Many studies have reported a correlation between GLUT1 expression level and the grade of tumor aggressiveness, which suggests that GLUT1 expression may be of prognostic significance. Therefore, GLUT1 is a key rate-limiting factor in the transport and glucose metabolism in cancer cells. This paper presents the current state of knowledge on GLUT1 regulation as well as its utility in the diagnosis and therapy of cancers.

  15. Trefoil factor 3 (TFF3 expression is regulated by insulin and glucose

    Directory of Open Access Journals (Sweden)

    Girolamo Jose Barrera Roa

    2013-04-01

    Full Text Available Introduction: Trefoil factors are effector molecules in gastrointestinal tract physiology. They are classified into three groups: the gastric peptides (TFF1, spasmolytic peptide (TFF2 and intestinal trefoil factor (TFF3. Previous studies have shown that trefoil factors are located and expressed in human endocrine pancreas suggesting that TFF3 play a role in: a pancreatic cells migration, b β-cell mitosis, and c pancreatic cells regeneration. We speculated that the presence of TFF3 in pancreas, could be associated to a possible regulation mechanism by insulin and glucose. To date, there are not reports whether the unbalance in carbohydrate metabolism observed in diabetes could affect the production or expression of TFF3.Methods: We determined the TFF3 levels and expression by immunoassay (ELISA and semi-quantitative RT-PCR technique respectively, of intestinal epithelial cells (HT-29 treated with glucose and insulin. Also,Real Time-PCR (RTq-PCR was done.Results: Increasing concentrations of glucose improved TFF3 expression and these levels were further elevated after insulin treatment. Insulin treatment also led to the up-regulation of human sodium/glucose transporter 1 (hSGLT1, which further increases intracellular glucose levels. Finally, we investigated theTFF3 levels in serum of diabetes mellitus type 1 (T1DM and healthy patients. Here we shown that serum TFF3 levels were down-regulated in T1DM and this levels were up-regulated after insulin treatment. Also, the TFF3 levels of healthy donors were up-regulated 2 h after breakfast.Conclusion: Our fi ndings suggest for the fi rst time that insulin signaling is important for TFF3 optimal expression in serum and intestinal epithelial cells.

  16. Stretch-stimulated glucose transport in skeletal muscle is regulated by Rac1

    Science.gov (United States)

    Sylow, Lykke; Møller, Lisbeth L V; Kleinert, Maximilian; Richter, Erik A; Jensen, Thomas E

    2015-01-01

    An alternative to the canonical insulin signalling pathway for glucose transport is muscle contraction/exercise. Mechanical stress is an integrated part of the muscle contraction/relaxation cycle, and passive stretch stimulates muscle glucose transport. However, the signalling mechanism regulating stretch-stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1, was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction- and insulin-stimulated glucose transport, however, its role in stretch-stimulated glucose transport and signalling is unknown. We therefore investigated whether stretch-induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle-specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton in isolated soleus and extensor digitorum longus muscles. In addition, the role of Rac1 in contraction-stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which cross-bridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin. Knockout as well as pharmacological inhibition of Rac1 reduced stretch-stimulated glucose transport by 30–50% in soleus and extensor digitorum longus muscle. The actin depolymerizing agent latrunculin B similarly decreased glucose transport in response to stretching by 40–50%. Rac1 inhibition reduced contraction-stimulated glucose transport by 30–40% in tension developing muscle but did not affect contraction-stimulated glucose transport in muscles in which force development was prevented. Our findings suggest that Rac1 and the actin cytoskeleton regulate stretch-stimulated glucose transport and that Rac1 is a required part of the mechanical stress-component of the contraction-stimulus to glucose transport in skeletal muscle. Key

  17. Intermittent hypoxia training in prediabetes patients: Beneficial effects on glucose homeostasis, hypoxia tolerance and gene expression.

    Science.gov (United States)

    Serebrovska, Tetiana V; Portnychenko, Alla G; Drevytska, Tetiana I; Portnichenko, Vladimir I; Xi, Lei; Egorov, Egor; Gavalko, Anna V; Naskalova, Svitlana; Chizhova, Valentina; Shatylo, Valeriy B

    2017-09-01

    The present study aimed at examining beneficial effects of intermittent hypoxia training (IHT) under prediabetic conditions. We investigate the effects of three-week IHT on blood glucose level, tolerance to acute hypoxia, and leukocyte mRNA expression of hypoxia inducible factor 1α (HIF-1α) and its target genes, i.e. insulin receptor, facilitated glucose transporter-solute carrier family-2, and potassium voltage-gated channel subfamily J. Seven healthy and 11 prediabetic men and women (44-70 years of age) were examined before, next day and one month after three-week IHT (3 sessions per week, each session consisting 4 cycles of 5-min 12% O 2 and 5-min room air breathing). We found that IHT afforded beneficial effects on glucose homeostasis in patients with prediabetes reducing fasting glucose and during standard oral glucose tolerance test. The most pronounced positive effects were observed at one month after IHT termination. IHT also significantly increased the tolerance to acute hypoxia (i.e. SaO 2 level at 20th min of breathing with 12% O 2 ) and improved functional parameters of respiratory and cardiovascular systems. IHT stimulated HIF-1α mRNA expression in blood leukocytes in healthy and prediabetic subjects, but in prediabetes patients the maximum increase was lagged. The greatest changes in mRNA expression of HIF-1α target genes occurred a month after IHT and coincided with the largest decrease in blood glucose levels. The higher expression of HIF-1α was positively associated with higher tolerance to hypoxia and better glucose homeostasis. In conclusion, our results suggest that IHT may be useful for preventing the development of type 2 diabetes. Impact statement The present study investigated the beneficial effects of intermittent hypoxia training (IHT) in humans under prediabetic conditions. We found that three-week moderate IHT induced higher HIF-1α mRNA expressions as well as its target genes, which were positively correlated with higher tolerance

  18. Humanin (HN) and glucose transporter 8 (GLUT8) in pregnancies complicated by intrauterine growth restriction.

    Science.gov (United States)

    Janzen, Carla; Lei, Margarida Y Y; Jeong, Il Seok D; Ganguly, Amit; Sullivan, Peggy; Paharkova, Vladislava; Capodanno, Gina; Nakamura, Hiromi; Perry, Alix; Shin, Bo-Chul; Lee, Kuk-Wha; Devaskar, Sherin U

    2018-01-01

    Intrauterine growth restriction (IUGR) results from a lack of nutrients transferred to the developing fetus, particularly oxygen and glucose. Increased expression of the cytoprotective mitochondrial peptide, humanin (HN), and the glucose transporter 8, GLUT8, has been reported under conditions of hypoxic stress. However, the presence and cellular localization of HN and GLUT8 in IUGR-related placental pathology remain unexplored. Thus, we undertook this study to investigate placental expression of HN and GLUT8 in IUGR-affected versus normal pregnancies. We found 1) increased HN expression in human IUGR-affected pregnancies on the maternal aspect of the placenta (extravillous trophoblastic (EVT) cytoplasm) compared to control (i.e. appropriate for gestational age) pregnancies, and a concomitant increase in GLUT8 expression in the same compartment, 2) HN and GLUT8 showed a protein-protein interaction by co-immunoprecipitation, 3) elevated HN and GLUT8 levels in vitro under simulated hypoxia in human EVT cells, HTR8/SVneo, and 4) increased HN expression but attenuated GLUT8 expression in vitro under serum deprivation in HTR8/SVneo cells. There was elevated HN expression with cytoplasmic localization to EVTs on the maternal aspect of the human placenta affected by IUGR, also associated with increased GLUT8 expression. We found that while hypoxia increased both HN and GLUT8, serum deprivation increased HN expression alone. Also, a protein-protein interaction between HN and GLUT8 suggests that their interaction may fulfill a biologic role that requires interdependency. Future investigations delineating molecular interactions between these proteins are required to fully uncover their role in IUGR-affected pregnancies.

  19. Na+-independent D-glucose transport in rabbit renal basolateral membranes

    International Nuclear Information System (INIS)

    Cheung, P.T.; Hammerman, M.R.

    1988-01-01

    To define the mechanism by which glucose is transported across the basolateral membrane of the renal proximal tubular cell, we measured D-[14C]glucose uptake in basolateral membrane vesicles from rabbit kidney. Na+-dependent D-glucose transport, demonstrable in brush-border vesicles, could not be demonstrated in basolateral membrane vesicles. In the absence of Na+, the uptake of D-[14C]glucose in basolateral vesicles was more rapid than that of L-[3H]glucose over a concentration range of 1-50 mM. Subtraction of the latter from the former uptakes revealed a saturable process with apparent Km of 9.9 mM and Vmax of 0.80 nmol.mg protein-1.s-1. To characterize the transport component of D-glucose uptake in basolateral vesicles, we measured trans stimulation of 2 mM D-[14C]glucose entry in the absence of Na+. Trans stimulation could be effected by preloading basolateral vesicles with D-glucose, 2-deoxy-D-glucose, or 3-O-methyl-D-glucose, but not with L-glucose or alpha-methyl-D-glucoside. Trans-stimulated D-[14C]glucose uptake was inhibited by 0.1 mM phloretin or cytochalasin B but not phlorizin. In contrast, Na+-dependent D-[14C]glucose transport in brush-border vesicles was inhibited by phlorizin but not phloretin or cytochalasin B. Our findings are consistent with the presence of a Na+-independent D-glucose transporter in the proximal tubular basolateral membrane with characteristics similar to those of transporters present in nonepithelial cells

  20. Effect of insulin and glucocorticoids on glucose transporters in rat adipocytes

    International Nuclear Information System (INIS)

    Carter-Su, C.; Okamoto, K.

    1987-01-01

    The ability of glucocorticoids to modify the effect of insulin on glucose (L-1- 3 H(N)]glucose and D-[ 14 C-U]glucose) transport was investigated in both intact isolated rat adipocytes and in membranes isolated from hormone-treated adipocytes. In intact adipocytes, dexamethasone, a potent synthetic glucocorticoid, inhibited insulin-stimulated 3-O-methylglucose transport at all concentrations of insulin tested. Insulin sensitivity, as well as the maximal response to insulin, was decreased by dexamethasone in the absence of a change in 125 I insulin binding. The inhibition was observed regardless of which hormone acted first, was blocked by actinomycin D, and resulted from a decrease in V/sub max/ rather than an increase in K/sub t/ of transport. In plasma membranes isolated from insulin-treated adipocytes, glucose transport activity and the amount of glucose transporter covalently labeled with [ 3 H]cytochalasin B were increased in parallel in a dose-dependent fashion. The amount of labeled transporter in a low-density microsomal fraction (LDMF) was decreased in a reciprocal fashion. In contrast, addition of dexamethasone to insulin-stimulated cells caused decreases in both transport activity and amount of labeled transporter in the plasma membranes. This was accompanied by a small increase in the amount of [ 3 H]cytochalasin B incorporated into the glucose transporter in the LDMF. These results are consistent with both insulin and glucocorticoids altering the distribution of glucose transporters between the plasma membrane and LDMF, in opposite directions

  1. Contribution of glucose transport to the control of the glycolytic flux in Trypanosoma brucei.

    NARCIS (Netherlands)

    Bakker, B.M.; Walsh, M.C.; ter Kuile, B.; Mensonides, F.I.C.; Michels, P.A.M.; Opperdoes, F.R.; Westerhoff, H.V.

    1999-01-01

    The rate of glucose transport across the plasma membrane of the bloodstream form of Trypanosoma brucei was modulated by titration of the hexose transporter with the inhibitor phloretin, and the effect on the glycolytic flux was measured. A rapid glucose uptake assay was developed to measure the

  2. Glucose Transporter Type 1 Deficiency Syndrome with Carbohydrate-Responsive Symptoms but without Epilepsy

    Science.gov (United States)

    Koy, Anne; Assmann, Birgit; Klepper, Joerg; Mayatepek, Ertan

    2011-01-01

    Glucose transporter type 1 deficiency syndrome (GLUT1-DS) is caused by a defect in glucose transport across the blood-brain barrier. The main symptoms are epilepsy, developmental delay, movement disorders, and deceleration of head circumference. A ketogenic diet has been shown to be effective in controlling epilepsy in GLUT1-DS. We report a female…

  3. Cellular distribution of glucose and monocarboxylate transporters in human brain white matter and multiple sclerosis lesions

    NARCIS (Netherlands)

    Nijland, P.G.; Michailidou, I.; Witte, M.E.; Mizee, M.R.; van der Pol, SM; Hof, B.; Reijerkerk, A.; Pellerin, L.; van der Valk, P.; de Vries, H.E.; van Horssen, J.

    2014-01-01

    To ensure efficient energy supply to the high demanding brain, nutrients are transported into brain cells via specific glucose (GLUT) and monocarboxylate transporters (MCT). Mitochondrial dysfunction and altered glucose metabolism are thought to play an important role in the progression of

  4. Influence of alpha-linked glucose on jejunal sodium-glucose co-transport activity in ruminants.

    Science.gov (United States)

    Bauer, M L; Harmon, D L; McLeod, K R; Huntington, G B

    2001-06-01

    Eight steers and 12 lambs were used in a completely randomized experimental design to determine the effect of partial alpha-amylase starch hydrolysate (SH) on small intestinal sodium-dependent glucose transport activity. Starch hydrolysate was delivered ruminally or abomasally to steers (960 g/day) and sheep (144 g/day) for 7 days. On day 7, the steers were rendered unconscious, exsanguinated and eviscerated. A 1-m section of jejunum was collected starting at the duodenojejunal flexure. Sheep were anaesthetized with pentobarbital and the second meter of small intestine (jejunum) was collected. Brush-border membrane vesicles were prepared and sodium-dependent glucose uptake activity was measured using the rapid uptake/filtration technique. Alkaline phosphatase and maltase activity was enriched by 8.2+/-0.5- and 8.4+/-1.2-fold in the vesicle preparation, respectively, and was not different between treatments. Abomasal SH increased (P=0.03) the Na/glucose co-transport approximately two-fold in both cattle (47.2-114.0+/-31.5 pmol/mgxsec) and sheep (77.4-152.0+/-25.7 pmol mg(-1) s(-1)). We conclude that Na/glucose co-transport activity by enterocytes responds to luminal alpha-linked glucose (from abomasal infusion) in ruminants, compared with controls. Intestinal maltase-specific activity does not respond to alpha-linked glucose in cattle, and decreases slightly in sheep.

  5. Stretch-stimulated glucose transport in skeletal muscle is regulated by Rac1

    DEFF Research Database (Denmark)

    Sylow, Lykke; Møller, Lisbeth L V; Kleinert, Maximilian

    2015-01-01

    regulating stretch-stimulated glucose transport is not well understood. We recently reported that the actin cytoskeleton regulating GTPase, Rac1 was activated in mouse muscle in response to stretching. Rac1 is a regulator of contraction- and insulin-stimulated glucose transport but its role in stretch......-stimulated glucose transport and signaling is unknown. We therefore investigated whether stretch-induced glucose transport in skeletal muscle required Rac1 and the actin cytoskeleton. We used muscle specific inducible Rac1 knockout mice as well as pharmacological inhibitors of Rac1 and the actin cytoskeleton...... in isolated soleus and EDL muscles. In addition, Rac1's role in contraction-stimulated glucose transport during conditions without mechanical load on the muscles was evaluated in loosely hanging muscles and muscles in which crossbridge formation was blocked by the myosin ATPase inhibitors BTS and Blebbistatin...

  6. Novel Roles for the Insulin-Regulated Glucose Transporter-4 in Hippocampally Dependent Memory.

    Science.gov (United States)

    Pearson-Leary, Jiah; McNay, Ewan C

    2016-11-23

    The insulin-regulated glucose transporter-4 (GluT4) is critical for insulin- and contractile-mediated glucose uptake in skeletal muscle. GluT4 is also expressed in some hippocampal neurons, but its functional role in the brain is unclear. Several established molecular modulators of memory processing regulate hippocampal GluT4 trafficking and hippocampal memory formation is limited by both glucose metabolism and insulin signaling. Therefore, we hypothesized that hippocampal GluT4 might be involved in memory processes. Here, we show that, in male rats, hippocampal GluT4 translocates to the plasma membrane after memory training and that acute, selective intrahippocampal inhibition of GluT4-mediated glucose transport impaired memory acquisition, but not memory retrieval. Other studies have shown that prolonged systemic GluT4 blockade causes insulin resistance. Unexpectedly, we found that prolonged hippocampal blockade of glucose transport through GluT4-upregulated markers of hippocampal insulin signaling prevented task-associated depletion of hippocampal glucose and enhanced both working and short-term memory while also impairing long-term memory. These effects were accompanied by increased expression of hippocampal AMPA GluR1 subunits and the neuronal GluT3, but decreased expression of hippocampal brain-derived neurotrophic factor, consistent with impaired ability to form long-term memories. Our findings are the first to show the cognitive impact of brain GluT4 modulation. They identify GluT4 as a key regulator of hippocampal memory processing and also suggest differential regulation of GluT4 in the hippocampus from that in peripheral tissues. The role of insulin-regulated glucose transporter-4 (GluT4) in the brain is unclear. In the current study, we demonstrate that GluT4 is a critical component of hippocampal memory processes. Memory training increased hippocampal GluT4 translocation and memory acquisition was impaired by GluT4 blockade. Unexpectedly, whereas long

  7. Expression systems for cloned xenobiotic transporters

    International Nuclear Information System (INIS)

    Pritchard, John B.; Miller, David S.

    2005-01-01

    One challenge of modern biology is to be able to match genes and their encoded proteins with events at the molecular, cellular, tissue, and organism levels, and thus, provide a multi-level understanding of gene function and dysfunction. How well this can be done for xenobiotic transporters depends on a knowledge of the genes expressed in the tissue, the cellular locations of the gene products (do they function for uptake or efflux?), and our ability to match substrates with transporters using information obtained from cloned transporters functioning in heterologous expression systems. Clearly, making a rational choice of expression system to use for the characterization and study of cloned xenobiotic transporters is a critical part of study design. This choice requires well-defined goals, as well as an understanding of the strengths and weaknesses of candidate expression systems

  8. Glucose transport by radiation-induced insulinoma and clonal pancreatic beta-cells

    International Nuclear Information System (INIS)

    Meglasson, M.D.; Manning, C.D.; Najafi, H.; Matschinsky, F.M.

    1986-01-01

    Sugar uptake was measured in dispersed cells prepared from radiation-induced insulinomas transplantable in NEDH rats and in three clonal beta-cell lines maintained in continuous culture (RIN m5F, RIN 1046, HIT). Uptake of D-glucose and 3-O-methyl-D-glucose by insulinoma cells was rapid so that the intracellular concentration of D-hexoses approximated the concentration in the incubation medium by 15-30 s. L-Glucose was taken up only slowly. 3-O-methyl-D-glucose uptake by RIN m5F, RIN 1046, and HIT cells was slow; with 1 mM 3-O-methylglucose in the medium, equilibrium was attained at 20 min, but with 10 mM 3-O-methylglucose, equilibrium was not attained even at 20 min. In HIT cells incubated with D-glucose for 30 min, the intracellular concentration of glucose was less than the medium glucose concentration, indicating glucose transport is a nonequilibrium reaction in this cell line. These data indicate that radiation-induced insulinoma cells retain the capacity of normal beta-cells to transport sugar at high rates. RIN m5F, RIN 1046, and HIT cells transport sugar slowly, however, and thus differ from normal beta-cells. In RIN m5F, RIN 1046, and HIT cells, unlike in normal beta-cells, glucose transport may be the site regulating glucose metabolism

  9. Low RNA Polymerase III activity results in up regulation of HXT2 glucose transporter independently of glucose signaling and despite changing environment.

    Directory of Open Access Journals (Sweden)

    Malgorzata Adamczyk

    Full Text Available Saccharomyces cerevisiae responds to glucose availability in the environment, inducing the expression of the low-affinity transporters and high-affinity transporters in a concentration dependent manner. This cellular decision making is controlled through finely tuned communication between multiple glucose sensing pathways including the Snf1-Mig1, Snf3/Rgt2-Rgt1 (SRR and cAMP-PKA pathways.We demonstrate the first evidence that RNA Polymerase III (RNAP III activity affects the expression of the glucose transporter HXT2 (RNA Polymerase II dependent-RNAP II at the level of transcription. Down-regulation of RNAP III activity in an rpc128-1007 mutant results in a significant increase in HXT2 mRNA, which is considered to respond only to low extracellular glucose concentrations. HXT2 expression is induced in the mutant regardless of the growth conditions either at high glucose concentration or in the presence of a non-fermentable carbon source such as glycerol. Using chromatin immunoprecipitation (ChIP, we found an increased association of Rgt1 and Tup1 transcription factors with the highly activated HXT2 promoter in the rpc128-1007 strain. Furthermore, by measuring cellular abundance of Mth1 corepressor, we found that in rpc128-1007, HXT2 gene expression was independent from Snf3/Rgt2-Rgt1 (SRR signaling. The Snf1 protein kinase complex, which needs to be active for the release from glucose repression, also did not appear perturbed in the mutated strain.These findings suggest that the general activity of RNAP III can indirectly affect the RNAP II transcriptional machinery on the HXT2 promoter when cellular perception transduced via the major signaling pathways, broadly recognized as on/off switch essential to either positive or negative HXT gene regulation, remain entirely intact. Further, Rgt1/Ssn6-Tup1 complex, which has a dual function in gene transcription as a repressor-activator complex, contributes to HXT2 transcriptional activation.

  10. Saccharomyces cerevisiae and metabolic activators: HXT3 gene expression and fructose/glucose discrepancy in sluggish fermentation conditions.

    Science.gov (United States)

    Díaz-Hellín, Patricia; Naranjo, Victoria; Úbeda, Juan; Briones, Ana

    2016-12-01

    When exposed to mixtures of glucose and fructose, as occurs during the fermentation of grape juice into wine, Saccharomyces cerevisiae uses these sugars at different rates. Moreover, glucose and fructose are transported by the same hexose transporters (HXT), which present a greater affinity for glucose, so that late in fermentation, fructose becomes the predominant sugar. Only a few commercial fermentation activators are available to optimally solve the problems this entails. The aim of this study was to investigate the relation between HXT3 gene expression and fructose/glucose discrepancy in two different media inoculated with a commercial wine strain of S. cerevisiae in the presence of three metabolic activators. Fermentation kinetics, vitality and major metabolites were also measured. Rehydration with ergosterol improved the area under the curve and the growth rate (µ max ) in both studied media. Also, the fructose/glucose discrepancy values were improved with all activator treatments, highlighting rehydration in the presence of ascorbic acid. The yeast rehydration process was demonstrated to influence HXT3 expression under the studied conditions. Tetrahydrofolic acid treatment greatly influenced HXT3 gene expression, especially on the 12th day of the fermentation process. To a lesser extent, ergosterol and ascorbic acid also improved this parameter.

  11. Differentiation of the insulin-sensitive glucose transporter in 3T3-L1 adipocytes

    International Nuclear Information System (INIS)

    Frost, S.C.; Baly, D.L.; Cushman, S.W.; Lane, M.D.; Simpson, I.A.

    1986-01-01

    3T3-L1 fibroblasts differentiate in culture to resemble adipocytes both morphologically and biochemically. Insulin-sensitive glucose transport, as measured by 2-deoxy-[1- 14 C]- glucose uptake in the undifferentiated cell is small (2X). In contrast, the rate of glucose transport in fully differentiated cells is elevated 15-fold over basal in the presence of insulin. To determine if this is due to an increase in the number of transporters/cell or accessibility to the transporters, the number of transporters was measured in subcellular fractions over differentiation using a 3 H-cytochalasin B binding assay. The increase in the rate of insulin-sensitive glucose transport directly parallels an increase in the number of transporters which reside in an insulin-responsive intracellular compartment. This observation was confirmed by identifying the transporters by immunoblotting using an antibody generated against the human erythrocyte transporter. The molecular weight of this transporter increases over differentiation from a single band of 40kDa to a heterogeneous triplet of 40, 44 and 48kDa. These data suggest that the transporter undergoes differential processing and that the functional, insulin-responsive transporter may be different from the insulin-insensitive (basal) transporter

  12. The Small Protein SgrT Controls Transport Activity of the Glucose-Specific Phosphotransferase System.

    Science.gov (United States)

    Lloyd, Chelsea R; Park, Seongjin; Fei, Jingyi; Vanderpool, Carin K

    2017-06-01

    The bacterial small RNA (sRNA) SgrS has been a fruitful model for discovery of novel RNA-based regulatory mechanisms and new facets of bacterial physiology and metabolism. SgrS is one of only a few characterized dual-function sRNAs. SgrS can control gene expression posttranscriptionally via sRNA-mRNA base-pairing interactions. Its second function is coding for the small protein SgrT. Previous work demonstrated that both functions contribute to relief of growth inhibition caused by glucose-phosphate stress, a condition characterized by disrupted glycolytic flux and accumulation of sugar phosphates. The base-pairing activity of SgrS has been the subject of numerous studies, but the activity of SgrT is less well characterized. Here, we provide evidence that SgrT acts to specifically inhibit the transport activity of the major glucose permease PtsG. Superresolution microscopy demonstrated that SgrT localizes to the cell membrane in a PtsG-dependent manner. Mutational analysis determined that residues in the N-terminal domain of PtsG are important for conferring sensitivity to SgrT-mediated inhibition of transport activity. Growth assays support a model in which SgrT-mediated inhibition of PtsG transport activity reduces accumulation of nonmetabolizable sugar phosphates and promotes utilization of alternative carbon sources by modulating carbon catabolite repression. The results of this study expand our understanding of a basic and well-studied biological problem, namely, how cells coordinate carbohydrate transport and metabolism. Further, this work highlights the complex activities that can be carried out by sRNAs and small proteins in bacteria. IMPORTANCE Sequencing, annotation and investigation of hundreds of bacterial genomes have identified vast numbers of small RNAs and small proteins, the majority of which have no known function. In this study, we explore the function of a small protein that acts in tandem with a well-characterized small RNA during metabolic

  13. Measurement of glucose and 2-deoxy-2-[18F]fluoro-D-glucose transport and phosphorylation rates in myocardium using dual-tracer kinetic experiments

    International Nuclear Information System (INIS)

    Huang, S.C.; Williams, B.A.; Barrio, J.R.; Nissenson, C.; Hoffman, E.J.; Phelps, M.E.; Krivokapich, J.

    1987-01-01

    To examine the use of 2-deoxy-2-[ 18 F]fluoro-D-glucose (2-FDG) as a glucose analog for measuring glucose utilization rate in myocardium, dual-tracer kinetic experiments with 2-FDG and 2-[ 3 H]glucose were performed in the perfused, isolated rabbit interventricular septum to measure simultaneously the transport and phosphorylation rates of glucose and 2-FDG. Results of the present study indicated that, in the septum, (i) the transport rate constants of 2-FDG and glucose were similar in magnitude, (ii) the phosphorylation rate constant for 2-FDG was about 60% of that of glucose, (iii) hypoxia caused an increase in phosphorylation rates of glucose and 2-FDG without affecting transport. 9 refs.; 1 figure; 3 tabs

  14. Glucose uptake and growth of glucose-limited chemostat cultures of Aspergillus niger and a disruptant lacking MstA, a high-affinity glucose transporter

    DEFF Research Database (Denmark)

    Jørgensen, Thomas R; vanKuyk, Patricia A; Poulsen, Bjarne R

    2007-01-01

    This is a study of high-affinity glucose uptake in Aspergillus niger and the effect of disruption of a high-affinity monosaccharide-transporter gene, mstA. The substrate saturation constant (K(s)) of a reference strain was about 15 microM in glucose-limited chemostat culture. Disruption of mst......-affinity uptake system of A. niger. The mstA disruptant and a reference strain were cultivated in glucose-limited chemostat cultures at low, intermediate and high dilution rate (D=0.07 h(-1), 0.14 h(-1) and 0.20 h(-1)). Mycelium harvested from steady-state cultures was subjected to glucose uptake assays...

  15. Glucose Transport into Everted Sacs of the Small Intestine of Mice

    Science.gov (United States)

    Hamilton, Kirk L.; Butt, A. Grant

    2013-01-01

    The Na[superscript +]-glucose cotransporter is a key transport protein that is responsible for absorbing Na[superscript +] and glucose from the luminal contents of the small intestine and reabsorption by the proximal straight tubule of the nephron. Robert K. Crane originally described the cellular model of absorption of Na[superscript +] and…

  16. Effect of physical training on glucose transporter protein and mRNA levels in rat adipocytes

    DEFF Research Database (Denmark)

    Stallknecht, B; Andersen, P H; Vinten, J

    1993-01-01

    Physical training increases insulin-stimulated glucose transport and the number of glucose transporters in adipocytes measured by cytochalasin B binding. In the present study we used immunoblotting to measure the abundance of two glucose transporters (GLUT-4, GLUT-1) in white adipocytes from...... trained rats. Furthermore, the abundance of the mRNAs for these proteins and glucose transport was measured. Rats were swim-trained for 10 wk, and adipocytes were isolated from epididymal fat pads. The amount of GLUT-4/adipocyte volume unit was significantly higher in trained animals compared with both...... age- and cell size-matched animals. The amount of GLUT-4 mRNA was also increased by training and it decreased with increasing age. Furthermore, young age as well as training was accompanied by relatively low GLUT-4 protein/mRNA and relatively high overall GLUT-4 efficiency (recruitability and...

  17. Reversible white matter lesions during ketogenic diet therapy in glucose transporter 1 deficiency syndrome.

    Science.gov (United States)

    Shiohama, Tadashi; Fujii, Katsunori; Takahashi, Satoru; Nakamura, Fumito; Kohno, Yoichi

    2013-12-01

    Glucose transporter type 1 deficiency syndrome is caused by brain energy failure resulting from a disturbance in glucose transport. We describe a 4-year-old boy with classical type glucose transporter type 1 deficiency syndrome with a heterozygous splice acceptor site mutation (c.517-2A>G) in the SLCA2A1 gene. We initiated a ketogenic diet at 4 months of age. However, even though his condition was good during ketogenic diet therapy, multiple cerebral white matter and right cerebellum lesions appeared at 9 months of age. The lesions in the cerebral white matter subsequently disappeared, indicating that white matter lesions during diet therapy may be reversible and independent of the ketogenic diet. This is the first report of reversible white matter lesions during ketogenic diet therapy in glucose transporter type 1 deficiency syndrome. Copyright © 2013 Elsevier Inc. All rights reserved.

  18. Global loss of bmal1 expression alters adipose tissue hormones, gene expression and glucose metabolism.

    Directory of Open Access Journals (Sweden)

    David John Kennaway

    Full Text Available The close relationship between circadian rhythm disruption and poor metabolic status is becoming increasingly evident, but role of adipokines is poorly understood. Here we investigated adipocyte function and the metabolic status of mice with a global loss of the core clock gene Bmal1 fed either a normal or a high fat diet (22% by weight. Bmal1 null mice aged 2 months were killed across 24 hours and plasma adiponectin and leptin, and adipose tissue expression of Adipoq, Lep, Retn and Nampt mRNA measured. Glucose, insulin and pyruvate tolerance tests were conducted and the expression of liver glycolytic and gluconeogenic enzyme mRNA determined. Bmal1 null mice displayed a pattern of increased plasma adiponectin and plasma leptin concentrations on both control and high fat diets. Bmal1 null male and female mice displayed increased adiposity (1.8 fold and 2.3 fold respectively on the normal diet, but the high fat diet did not exaggerate these differences. Despite normal glucose and insulin tolerance, Bmal1 null mice had increased production of glucose from pyruvate, implying increased liver gluconeogenesis. The Bmal1 null mice had arrhythmic clock gene expression in epigonadal fat and liver, and loss of rhythmic transcription of a range of metabolic genes. Furthermore, the expression of epigonadal fat Adipoq, Retn, Nampt, AdipoR1 and AdipoR2 and liver Pfkfb3 mRNA were down-regulated. These results show for the first time that global loss of Bmal1, and the consequent arrhythmicity, results in compensatory changes in adipokines involved in the cellular control of glucose metabolism.

  19. Early alterations in soleus GLUT-4, glucose transport, and glycogen in voluntary running rats

    Science.gov (United States)

    Henriksen, Erik J.; Halseth, Amy E.

    1994-01-01

    Voluntary wheel running (WR) by juvenile female rats was used as a noninterventional model of soleus muscle functional overload to study the regulation of insulin-stimulated glucose transport activity by the glucose transporter (GLUT-4 isoform) protein level and glycogen concentration. Soleus total protein content was significantly greater (+18%;P greater than 0.05) than in age-matched controls after 1 wk of WR, and this hypertrophic response continued in weeks 2-4 (+24-32%). GLUT-4 protein was 39% greater than in controls in 1-wk WR soleus, and this adaptation was accompanied by a similar increase in in vitro insulin-stimulated glucose transport activity(+29%). After 2 and 4 wk of WR, however, insulin-stimulated glucose transport activity had returned to control levels, despite a continued elevation (+25-28%) of GLUT-4 protein. At these two time points, glycogen concentration was significantly enhanced in WR soleus (+21-42%), which coincided with significant reductions in glycogen synthase activity ratios (-23 to-41%). These results indicate that, in this model of soleus muscle functional overload, the GLUT-4 protein level may initially regulate insulin-stimulated glucose transport activity in the absence of changes in other modifying factors. However,this regulation of glucose transport activity by GLUT-4 protein may be subsequently overridden by elevated glycogen concentration.

  20. A glucose transporter can mediate ribose uptake: definition of residues that confer substrate specificity in a sugar transporter.

    Science.gov (United States)

    Naula, Christina M; Logan, Flora J; Logan, Flora M; Wong, Pui Ee; Barrett, Michael P; Burchmore, Richard J

    2010-09-24

    Sugars, the major energy source for many organisms, must be transported across biological membranes. Glucose is the most abundant sugar in human plasma and in many other biological systems and has been the primary focus of sugar transporter studies in eukaryotes. We have previously cloned and characterized a family of glucose transporter genes from the protozoan parasite Leishmania. These transporters, called LmGT1, LmGT2, and LmGT3, are homologous to the well characterized glucose transporter (GLUT) family of mammalian glucose transporters. We have demonstrated that LmGT proteins are important for parasite viability. Here we show that one of these transporters, LmGT2, is a more effective carrier of the pentose sugar d-ribose than LmGT3, which has a 6-fold lower relative specificity (V(max)/K(m)) for ribose. A pair of threonine residues, located in the putative extracellular loops joining transmembrane helices 3 to 4 and 7 to 8, define a filter that limits ribose approaching the exofacial substrate binding pocket in LmGT3. When these threonines are substituted by alanine residues, as found in LmGT2, the LmGT3 permease acquires ribose permease activity that is similar to that of LmGT2. The location of these residues in hydrophilic loops supports recent suggestions that substrate recognition is separated from substrate binding and translocation in this important group of transporters.

  1. Radiation inactivation studies on the rabbit kidney sodium-dependent glucose transporter.

    Science.gov (United States)

    Takahashi, M; Malathi, P; Preiser, H; Jung, C Y

    1985-09-05

    Rabbit kidney cortical brush-border membrane vesicles were irradiated in the frozen state with increasing doses of high energy electrons from a Van de Graaff generator. Sodium-dependent D-glucose and L-alanine transport showed a simple exponential loss of activity with increasing radiation dosage. Target size calculation based on these data gives estimates of 1.0 X 10(6) daltons for the glucose transporter and 1.2 X 10(6) daltons for the alanine transporter. A highly purified glucose transport protein extracted from rabbit kidney cortex was similarly irradiated both before and after reconstitution into liposomes. The target size of this purified glucose transporter was 343,000 daltons, based on inactivation of transport. The intensity of the major 165,000-dalton sodium dodecyl sulfate-gel electrophoresis band of this preparation was decreased by radiation. The decrease in staining intensity was dose-dependent, yielding a target size of 298,000 daltons, in situ. We propose that the purified glucose transporter reconstituted into liposomes is a tetramer comprised of 85,000-dalton subunits.

  2. Hepatic Transporter Expression in Metabolic Syndrome: Phenotype, Serum Metabolic Hormones, and Transcription Factor Expression.

    Science.gov (United States)

    Donepudi, Ajay C; Cheng, Qiuqiong; Lu, Zhenqiang James; Cherrington, Nathan J; Slitt, Angela L

    2016-04-01

    Metabolic syndrome is a multifactorial disease associated with obesity, insulin resistance, diabetes, and the alteration of multiple metabolic hormones. Obesity rates have been rising worldwide, which increases our need to understand how this population will respond to drugs and exposure to other chemicals. The purpose of this study was to determine in lean and obese mice the ontogeny of clinical biomarkers such as serum hormone and blood glucose levels as well as the physiologic markers that correlate with nuclear receptor- and transporter-related pathways. Livers from male and female wild-type (WT) (C57BL/6) and ob/ob mice littermates were collected before, during, and after the onset of obesity. Serum hormone and mRNA levels were analyzed. Physiologic changes and gene expression during maturation and progression to obesity were performed and correlation analysis was performed using canonical correlations. Significant ontogenic changes in both WT and ob/ob mice were observed and these ontogenic changes differ in ob/ob mice with the development of obesity. In males and females, the ontogenic pattern of the expression of genes such as Abcc3, 4, Abcg2, Cyp2b10, and 4a14 started to differ from week 3, and became significant at weeks 4 and 8 in ob/ob mice compared with WT mice. In obese males, serum resistin, glucagon, and glucose levels correlated with the expression of most hepatic ATP-binding cassette (Abc) transporters, whereas in obese females, serum glucagon-like peptide 1 levels were correlated with most hepatic uptake transporters and P450 enzymes. Overall, the correlation between physiologic changes and gene expression indicate that metabolism-related hormones may play a role in regulating the genes involved in drug metabolism and transport. Copyright © 2016 by The American Society for Pharmacology and Experimental Therapeutics.

  3. Wortmannin inhibits both insulin- and contraction-stimulated glucose uptake and transport in rat skeletal muscle

    DEFF Research Database (Denmark)

    Wojtaszewski, Jørgen; Hansen, B F; Ursø, Birgitte

    1996-01-01

    stimulation but was unaffected by contractions. In addition, the insulin-stimulated PI 3-kinase activity and muscle glucose uptake and transport in individual muscles were dose-dependently inhibited by wortmannin with one-half maximal inhibition values of approximately 10 nM and total inhibition at 1 micro......The role of phosphatidylinositol (PI) 3-kinase for insulin- and contraction-stimulated muscle glucose transport was investigated in rat skeletal muscle perfused with a cell-free perfusate. The insulin receptor substrate-1-associated PI 3-kinase activity was increased sixfold upon insulin......-stimulated glucose uptake but also decreased the contractility. In conclusion, inhibition of PI 3-kinase with wortmannin in skeletal muscle coincides with inhibition of insulin-stimulated glucose uptake and transport. Furthermore, in contrast to recent findings in incubated muscle, wortmannin also inhibited...

  4. Decreased muscle GLUT-4 and contraction-induced glucose transport after eccentric contractions

    DEFF Research Database (Denmark)

    Kristiansen, S; Asp, Svend; Richter, Erik

    1996-01-01

    Eccentric exercise causes muscle damage and decreased muscle glycogen and glucose transporter isoform (GLUT-4) protein content. We investigated whether the contraction-induced increase in skeletal muscle glucose transport and muscle performance is affected by prior eccentric contractions. The calf...... muscles from rats were stimulated for eccentric (EC) or concentric (CC) contractions or were passively stretched (ST). Muscles from unstimulated control (CT) rats were also studied. Two days later, all rats had their isolated hindlimbs perfused either at rest or during 15 min of isometric muscle...... than in CT rats. In the GW and GR muscle, prior eccentric exercise decreased contraction-induced stimulation of glucose transport compared with CT, ST, and CC rats despite no difference in tension development and oxygen uptake among the groups. There was no change in total GLUT-4 content and glucose...

  5. Phenolics from Whole Grain Oat Products as Modifiers of Starch Digestion and Intestinal Glucose Transport.

    Science.gov (United States)

    Li, Min; Koecher, Katie; Hansen, Laura; Ferruzzi, Mario G

    2017-08-16

    Four oat varieties and three product forms (porridge, cereal, and snack bar) were assessed to determine the impact of oat phenolics on starch digestibility and intestinal glucose transport. α-Amylase activity was enhanced by 20 GAE μM (gallic acid equivalent) of phenolics extracted from oat (96.7-118%, p transport of d-glucose-1,2,3,4,5,6,6-d 7 by Caco-2 monolayers over 60 min. Oat foods were then subjected to a coupled in vitro digestion/Caco-2 intestinal cell model to determine relevance to whole food systems. Digestive release of glucose was similar among products; however, glucose transport was significantly reduced from digesta of GMI 423 porridge and puffed cereal by 34% ± 12% and 20% ± 10% (p < 0.05) at 60 min. Results suggest phenolics might be a factor modulating glycemic response of oat products.

  6. Effect of selective blockade of oxygen consumption, glucose transport, and Ca2+ influx on thyroxine action in human mononuclear cells

    DEFF Research Database (Denmark)

    Kvetny, J; Matzen, L E

    1990-01-01

    The effect of selective blockade of cellular glucose transporters, Ca2+ influx, and mitochondrial oxygen consumption on thyroxine (T4)-stimulated oxygen consumption and glucose uptake was examined in human mononuclear blood cells. Blockade of glucose transporters by cytochalasin B (1 x 10(-5) mol...

  7. Aqueous extract of tamarind seeds selectively increases glucose transporter-2, glucose transporter-4, and islets' intracellular calcium levels and stimulates β-cell proliferation resulting in improved glucose homeostasis in rats with streptozotocin-induced diabetes mellitus.

    Science.gov (United States)

    Sole, Sushant Shivdas; Srinivasan, B P

    2012-08-01

    Tamarindus indica Linn. has been in use for a long time in Asian food and traditional medicine for different diseases including diabetes and obesity. However, the molecular mechanisms of these effects have not been fully understood. In view of the multidimensional activity of tamarind seeds due to their having high levels of polyphenols and flavonoids, we hypothesized that the insulin mimetic effect of aqueous tamarind seed extract (TSE) might increase glucose uptake through improvement in the expression of genes of the glucose transporter (GLUT) family and sterol regulatory element-binding proteins (SREBP) 1c messenger RNA (mRNA) in the liver. Daily oral administration of TSE to streptozotocin (STZ)-induced (90 mg/kg intraperitoneally) type 2 diabetic male Wistar rats at different doses (120 and 240 mg/kg body weight) for 4 weeks showed positive correlation with intracellular calcium and insulin release in isolated islets of Langerhans. Tamarind seed extract supplementation significantly improved the GLUT-2 protein and SREBP-1c mRNA expression in the liver and GLUT-4 protein and mRNA expression in the skeletal muscles of diabetic rats. The elevated levels of serum nitric oxide (NO), glycosylated hemoglobin level (hemoglobin (A1c)) and tumor necrosis factor α (TNF-α) decreased after TSE administration. Immunohistochemical findings revealed that TSE abrogated STZ-induced apoptosis and increased β-cell neogenesis, indicating its effect on islets and β-cell mass. In conclusion, it was found that the antidiabetic effect of TSE on STZ-induced diabetes resulted from complex mechanisms of β-cell neogenesis, calcium handling, GLUT-2, GLUT-4, and SREBP-1c. These findings show the scope for formulating a new herbal drug for diabetes therapy. Copyright © 2012 Elsevier Inc. All rights reserved.

  8. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport

    Science.gov (United States)

    Naftalin, Richard J; Cunningham, Philip; Afzal-Ahmed, Iram

    2004-01-01

    Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide galanin in human erythrocytes in vitro. The potencies of nootropic drugs in opposing scopolamine-induced memory loss correlate with their potencies in antagonising pentobarbital inhibition of erythrocyte glucose transport in vitro (PPiracetam and TRH have no direct effects on net glucose transport, but competitively antagonise hypnotic drug inhibition of glucose transport. Other nootropics, like aniracetam and levetiracetam, while antagonising pentobarbital action, also inhibit glucose transport. Analeptics like bemigride and methamphetamine are more potent inhibitors of glucose transport than antagonists of hypnotic action on glucose transport. There are similarities between amino-acid sequences in human glucose transport protein isoform 1 (GLUT1) and the benzodiazepine-binding domains of GABAA (gamma amino butyric acid) receptor subunits. Mapped on a 3D template of GLUT1, these homologies suggest that the site of diazepam and piracetam interaction is a pocket outside the central hydrophilic pore region. Nootropic pyrrolidone antagonism of hypnotic drug inhibition of glucose transport in vitro may be an analogue of TRH antagonism of galanin-induced narcosis. PMID:15148255

  9. Phylogenetic analysis and tissue distribution of elasmobranch glucose transporters and their response to feeding

    Directory of Open Access Journals (Sweden)

    Courtney A. Deck

    2016-03-01

    Full Text Available Elasmobranch diets consist of high quantities of protein and lipids, but very low levels of carbohydrates including glucose. Reflecting this diet, most tissues use lipids and ketone bodies as their main metabolic fuel. However, the rectal gland has been shown to be dependent on glucose as a fuel, so we hypothesized that glucose transporters (GLUTs would be present and upregulated in the gland during times of activation (e.g. following a meal. In this study, we searched for and identified putative class I GLUTs in three elasmobranchs and a holocephalan using transcriptomes, and used these to reconstruct a Bayesian phylogeny. We determined that each of the four species possessed three of the four class I GLUT sequences, but the identities of the isoforms present in each species differed between the elasmobranchs (GLUT1, 3 and 4 and the holocephalan (GLUT1, 2 and 3. We then used qPCR to measure mRNA levels of these GLUTs in the rectal gland, liver, intestine, and muscle of fed and starved spiny dogfish (Squalus suckleyi. The rectal gland data showed higher mRNA levels of GLUT4 in the starved relative to the fed fish. In the muscle, both GLUT1 and 4 were significantly elevated at 24 h post-feeding, as was the case for GLUT4 in the liver. In the intestine on the other hand, GLUT4 was significantly elevated by 6 h post-feeding, remaining elevated through 48 h. We suggest that GLUT4 has taken on the role of GLUT2 in elasmobranchs as the expression patterns observed in the liver and intestine are representative of GLUT2 in other vertebrates.

  10. Gene expression profiles of glucose toxicity-exposed islet microvascular endothelial cells.

    Science.gov (United States)

    Liu, Mingming; Lu, Wenbao; Hou, Qunxing; Wang, Bing; Sheng, Youming; Wu, Qingbin; Li, Bingwei; Liu, Xueting; Zhang, Xiaoyan; Li, Ailing; Zhang, Honggang; Xiu, Ruijuan

    2018-03-25

    Islet microcirculation is mainly composed by IMECs. The aim of the study was to investigate the differences in gene expression profiles of IMECs upon glucose toxicity exposure and insulin treatment. IMECs were treated with 5.6 mmol L -1 glucose, 35 mmol L -1 glucose, and 35 mmol L -1 glucose plus 10 -8  mol L -1 insulin, respectively. Gene expression profiles were determined by microarray and verified by qPCR. GO terms and KEGG analysis were performed to assess the potential roles of differentially expressed genes. The interaction and expression tendency of differentially expressed genes were analyzed by Path-Net algorithm. Compared with glucose toxicity-exposed IMECs, 1574 mRNAs in control group and 2870 mRNAs in insulin-treated IMECs were identified with differential expression, respectively. GO and KEGG pathway analysis revealed that these genes conferred roles in regulation of apoptosis, proliferation, migration, adhesion, and metabolic process etc. Additionally, MAPK signaling pathway and apoptosis were the dominant nodes in Path-Net. IMECs survival and function pathways were significantly changed, and the expression tendency of genes from euglycemia and glucose toxicity exposure to insulin treatment was revealed and enriched in 7 patterns. Our study provides a microcirculatory framework for gene expression profiles of glucose toxicity-exposed IMECs. © 2018 John Wiley & Sons Ltd.

  11. Comparison of glucose and lipid metabolic gene expressions between fat and lean lines of rainbow trout after a glucose load.

    Directory of Open Access Journals (Sweden)

    Junyan Jin

    Full Text Available Two experimental rainbow trout lines developed through divergent selection for low (Lean 'L' line or high (Fat 'F' line muscle fat content were used as models to study the genetic determinism of fat depots. Previous nutritional studies suggested that the F line had a better capability to use glucose than the L line during feeding trials. Based on that, we put forward the hypothesis that F line has a greater metabolic ability to clear a glucose load effectively, compared to L line. In order to test this hypothesis, 250 mg/kg glucose was intraperitoneally injected to the two rainbow trout lines fasted for 48 h. Hyperglycemia was observed after glucose treatment in both lines without affecting the phosphorylation of AMPK (cellular energy sensor and Akt-TOR (insulin signaling components. Liver glucokinase and glucose-6-phosphate dehydrogenase expression levels were increased by glucose, whereas mRNA levels of β-oxidation enzymes (CPT1a, CPT1b, HOAD and ACO were down-regulated in the white skeletal muscle of both lines. Regarding the genotype effect, concordant with normoglycemia at 12 h after glucose treatment, higher muscle glycogen was found in F line compared to L line which exhibited hyperglycemia. Moreover, mRNA levels of hepatic glycolytic enzymes (GK, 6PFK and PK, gluconeogenic enzyme PEPCK and muscle fatty acid oxidation enzymes (CPT1a, CPT1b and HOAD were concurrently higher in the F line. Overall, these findings suggest that F line may have a better ability to maintain glucose homeostasis than L line.

  12. Transport and metabolism of fumaric acid in Saccharomyces cerevisiae in aerobic glucose-limited chemostat culture.

    Science.gov (United States)

    Shah, Mihir V; van Mastrigt, Oscar; Heijnen, Joseph J; van Gulik, Walter M

    2016-04-01

    Currently, research is being focused on the industrial-scale production of fumaric acid and other relevant organic acids from renewable feedstocks via fermentation, preferably at low pH for better product recovery. However, at low pH a large fraction of the extracellular acid is present in the undissociated form, which is lipophilic and can diffuse into the cell. There have been no studies done on the impact of high extracellular concentrations of fumaric acid under aerobic conditions in S. cerevisiae, which is a relevant issue to study for industrial-scale production. In this work we studied the uptake and metabolism of fumaric acid in S. cerevisiae in glucose-limited chemostat cultures at a cultivation pH of 3.0 (pH medium. The experiments were carried out with the wild-type S. cerevisiae CEN.PK 113-7D and an engineered S. cerevisiae ADIS 244 expressing a heterologous dicarboxylic acid transporter (DCT-02) from Aspergillus niger, to examine whether it would be capable of exporting fumaric acid. We observed that fumaric acid entered the cells most likely via passive diffusion of the undissociated form. Approximately two-thirds of the fumaric acid in the feed was metabolized together with glucose. From metabolic flux analysis, an increased ATP dissipation was observed only at high intracellular concentrations of fumarate, possibly due to the export of fumarate via an ABC transporter. The implications of our results for the industrial-scale production of fumaric acid are discussed. Copyright © 2015 John Wiley & Sons, Ltd.

  13. Gestational Protein Restriction Impairs Insulin-Regulated Glucose Transport Mechanisms in Gastrocnemius Muscles of Adult Male Offspring

    Science.gov (United States)

    Blesson, Chellakkan S.; Sathishkumar, Kunju; Chinnathambi, Vijayakumar

    2014-01-01

    Type II diabetes originates from various genetic and environmental factors. Recent studies showed that an adverse uterine environment such as that caused by a gestational low-protein (LP) diet can cause insulin resistance in adult offspring. The mechanism of insulin resistance induced by gestational protein restriction is not clearly understood. Our aim was to investigate the role of insulin signaling molecules in gastrocnemius muscles of gestational LP diet–exposed male offspring to understand their role in LP-induced insulin resistance. Pregnant Wistar rats were fed a control (20% protein) or isocaloric LP (6%) diet from gestational day 4 until delivery and a normal diet after weaning. Only male offspring were used in this study. Glucose and insulin responses were assessed after a glucose tolerance test. mRNA and protein levels of molecules involved in insulin signaling were assessed at 4 months in gastrocnemius muscles. Muscles were incubated ex vivo with insulin to evaluate insulin-induced phosphorylation of insulin receptor (IR), Insulin receptor substrate-1, Akt, and AS160. LP diet-fed rats gained less weight than controls during pregnancy. Male pups from LP diet–fed mothers were smaller but exhibited catch-up growth. Plasma glucose and insulin levels were elevated in LP offspring when subjected to a glucose tolerance test; however, fasting levels were comparable. LP offspring showed increased expression of IR and AS160 in gastrocnemius muscles. Ex vivo treatment of muscles with insulin showed increased phosphorylation of IR (Tyr972) in controls, but LP rats showed higher basal phosphorylation. Phosphorylation of Insulin receptor substrate-1 (Tyr608, Tyr895, Ser307, and Ser318) and AS160 (Thr642) were defective in LP offspring. Further, glucose transporter type 4 translocation in LP offspring was also impaired. A gestational LP diet leads to insulin resistance in adult offspring by a mechanism involving inefficient insulin-induced IR, Insulin receptor

  14. Gestational protein restriction impairs insulin-regulated glucose transport mechanisms in gastrocnemius muscles of adult male offspring.

    Science.gov (United States)

    Blesson, Chellakkan S; Sathishkumar, Kunju; Chinnathambi, Vijayakumar; Yallampalli, Chandrasekhar

    2014-08-01

    Type II diabetes originates from various genetic and environmental factors. Recent studies showed that an adverse uterine environment such as that caused by a gestational low-protein (LP) diet can cause insulin resistance in adult offspring. The mechanism of insulin resistance induced by gestational protein restriction is not clearly understood. Our aim was to investigate the role of insulin signaling molecules in gastrocnemius muscles of gestational LP diet-exposed male offspring to understand their role in LP-induced insulin resistance. Pregnant Wistar rats were fed a control (20% protein) or isocaloric LP (6%) diet from gestational day 4 until delivery and a normal diet after weaning. Only male offspring were used in this study. Glucose and insulin responses were assessed after a glucose tolerance test. mRNA and protein levels of molecules involved in insulin signaling were assessed at 4 months in gastrocnemius muscles. Muscles were incubated ex vivo with insulin to evaluate insulin-induced phosphorylation of insulin receptor (IR), Insulin receptor substrate-1, Akt, and AS160. LP diet-fed rats gained less weight than controls during pregnancy. Male pups from LP diet-fed mothers were smaller but exhibited catch-up growth. Plasma glucose and insulin levels were elevated in LP offspring when subjected to a glucose tolerance test; however, fasting levels were comparable. LP offspring showed increased expression of IR and AS160 in gastrocnemius muscles. Ex vivo treatment of muscles with insulin showed increased phosphorylation of IR (Tyr972) in controls, but LP rats showed higher basal phosphorylation. Phosphorylation of Insulin receptor substrate-1 (Tyr608, Tyr895, Ser307, and Ser318) and AS160 (Thr642) were defective in LP offspring. Further, glucose transporter type 4 translocation in LP offspring was also impaired. A gestational LP diet leads to insulin resistance in adult offspring by a mechanism involving inefficient insulin-induced IR, Insulin receptor

  15. Derivativation of the human erythrocyte glucose transporter using a novel forskolin photoaffinity label

    Energy Technology Data Exchange (ETDEWEB)

    Wadzinski, B.; Shanahan, M.; Ruoho, A.

    1987-05-01

    An iodinated photoaffinity label for the glucose transporter, 3-iodo-4-azidophenethylamido-7-0-succinyldeacetyl-forskolin (IAPS-Fsk), has been synthesized, purified, and characterized. The K/sub i/ for inhibition of 3-0-methylglucose transport by TAPS-Fsk in human erythrocytes was found to be 0.1 uM. The carrier-free radioiodinated label has been shown to be a highly specific photoaffinity label for the human erythrocyte glucose transporter. Photolysis of erythrocyte membranes with 1-10 nM (I-125)IAPS-Fsk and analysis by SDS-PAGE showed specific derivatization of a broad band with an apparent molecular weight of 40-70 kDa. Photoincorporation using 2 nM (I-125)IAPS-Fsk was protected with D-glucose, cytochalasin B, and forskolin. No protection was observed with L-glucose. Endo-B-galactosidase digestion and trypsinization of (I-125)IAPS-Fsk labelled erythrocytes reduced the specifically radiolabelled transporter to 40 kDa and 18 kDa respectively. (I-125)-IAPS-Fsk will be used to study the structural aspects of the glucose transporter.

  16. Glucose uptake and transport in contracting, perfused rat muscle with different pre-contraction glycogen concentrations

    DEFF Research Database (Denmark)

    Hespel, P; Richter, Erik

    1990-01-01

    on the preceding day. 4. Muscle membrane glucose transport, as measured by the rate of accumulation of 14C-3-O-methylglucose in the contracting muscles, was 25% lower in supercompensated than in glycogen-depleted muscles at the onset as well as at the end of the 15 min contraction period. 5. Intracellular......1. Glucose uptake and transport, muscle glycogen, free glucose and glucose-6-phosphate concentrations were studied in perfused resting and contracting rat skeletal muscle with different pre-contraction glycogen concentrations. Rats were pre-conditioned by a combination of swimming exercise and diet......, resulting in either low (glycogen-depleted rats), normal (control rats) or high (supercompensated rats) muscle glycogen concentrations at the time their hindlimbs were perfused. 2. Compared with control rats, pre-contraction muscle glycogen concentration was approximately 40% lower in glycogen-depleted rats...

  17. A Glimpse of Membrane Transport through Structures-Advances in the Structural Biology of the GLUT Glucose Transporters.

    Science.gov (United States)

    Yan, Nieng

    2017-08-18

    The cellular uptake of glucose is an essential physiological process, and movement of glucose across biological membranes requires specialized transporters. The major facilitator superfamily glucose transporters GLUTs, encoded by the SLC2A genes, have been a paradigm for functional, mechanistic, and structural understanding of solute transport in the past century. This review starts with a glimpse into the structural biology of membrane proteins and particularly membrane transport proteins, enumerating the landmark structures in the past 25years. The recent breakthrough in the structural elucidation of GLUTs is then elaborated following a brief overview of the research history of these archetypal transporters, their functional specificity, and physiological and pathophysiological significances. Structures of GLUT1, GLUT3, and GLUT5 in distinct transport and/or ligand-binding states reveal detailed mechanisms of the alternating access transport cycle and substrate recognition, and thus illuminate a path by which structure-based drug design may be applied to help discover novel therapeutics against several debilitating human diseases associated with GLUT malfunction and/or misregulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Early decline in glucose transport and metabolism precedes shift to ketogenic system in female aging and Alzheimer's mouse brain: implication for bioenergetic intervention.

    Science.gov (United States)

    Ding, Fan; Yao, Jia; Rettberg, Jamaica R; Chen, Shuhua; Brinton, Roberta Diaz

    2013-01-01

    We previously demonstrated that mitochondrial bioenergetic deficits in the female brain accompanied reproductive senescence and was accompanied by a shift from an aerobic glycolytic to a ketogenic phenotype. Herein, we investigated the relationship between systems of fuel supply, transport and mitochondrial metabolic enzyme expression/activity during aging (3-15 months) in the hippocampus of nontransgenic (nonTg) background and 3xTgAD female mice. Results indicate that during female brain aging, both nonTg and 3xTgAD brains undergo significant decline in glucose transport, as detected by FDG-microPET, between 6-9 months of age just prior to the transition into reproductive senescence. The deficit in brain metabolism was sustained thereafter. Decline in glucose transport coincided with significant decline in neuronal glucose transporter expression and hexokinase activity with a concomitant rise in phosphorylated/inactivated pyruvate dehydrogenase. Lactate utilization declined in parallel to the decline in glucose transport suggesting lactate did not serve as an alternative fuel. An adaptive response in the nonTg hippocampus was a shift to transport and utilization of ketone bodies as an alternative fuel. In the 3xTgAD brain, utilization of ketone bodies as an alternative fuel was evident at the earliest age investigated and declined thereafter. The 3xTgAD adaptive response was to substantially increase monocarboxylate transporters in neurons while decreasing their expression at the BBB and in astrocytes. Collectively, these data indicate that the earliest change in the metabolic system of the aging female brain is the decline in neuronal glucose transport and metabolism followed by decline in mitochondrial function. The adaptive shift to the ketogenic system as an alternative fuel coincided with decline in mitochondrial function. Translationally, these data provide insights into the earliest events in bioenergetic aging of the female brain and provide potential

  19. Development and potential role of type-2 sodium-glucose transporter inhibitors for management of type 2 diabetes.

    Science.gov (United States)

    Hardman, Timothy Colin; Dubrey, Simon William

    2011-09-01

    There is a recognized need for new treatment options for type 2 diabetes mellitus (T2DM). Recovery of glucose from the glomerular filtrate represents an important mechanism in maintaining glucose homeostasis and represents a novel target for the management of T2DM. Recovery of glucose from the glomerular filtrate is executed principally by the type 2 sodium-glucose cotransporter (SGLT2). Inhibition of SGLT2 promotes glucose excretion and normalizes glycemia in animal models. First reports of specifically designed SGLT2 inhibitors began to appear in the second half of the 1990s. Several candidate SGLT2 inhibitors are currently under development, with four in the later stages of clinical testing. The safety profile of SGLT2 inhibitors is expected to be good, as their target is a highly specific membrane transporter expressed almost exclusively within the renal tubules. One safety concern is that of glycosuria, which could predispose patients to increased urinary tract infections. So far the reported safety profile of SGLT2 inhibitors in clinical studies appears to confirm that the class is well tolerated. Where SGLT2 inhibitors will fit in the current cascade of treatments for T2DM has yet to be established. The expected favorable safety profile and insulin-independent mechanism of action appear to support their use in combination with other antidiabetic drugs. Promotion of glucose excretion introduces the opportunity to clear calories (80-90 g [300-400 calories] of glucose per day) in patients that are generally overweight, and is expected to work synergistically with weight reduction programs. Experience will most likely lead to better understanding of which patients are likely to respond best to SGLT2 inhibitors, and under what circumstances.

  20. GDM-Induced Macrosomia Is Reversed by Cav-1 via AMPK-Mediated Fatty Acid Transport and GLUT1-Mediated Glucose Transport in Placenta.

    Science.gov (United States)

    Yao, Guo; Zhang, Yafang; Wang, Di; Yang, Ruirui; Sang, Hui; Han, Linlin; Zhu, Yuexia; Lu, Yanyan; Tan, Yeke; Shang, Zhanping

    2017-01-01

    To investigate if the role of Cav-1 in GDM-induced macrosomia is through regulating AMPK signaling pathway in placenta. We used diagnostic criteria of gestational diabetes mellitus (GDM) and macrosomia to separate and compare placental protein and mRNA levels from GDM with macrosomia group (GDMM), GDM with normal birth weight group (GDMN) and normal glucose tolerance (NGT) with normal birth weight group (CON). Western blotting was performed to examine differentially expressed proteins of caveolin-1 (Cav-1) and Adenosine monophosphate-activated protein kinase (AMPK) signaling pathway related proteins, including phosphorylated-AMPKα(Thr172), AMPKα, phosphorylated-Acetyl-CoA carboxylase(Ser79) (p-ACC(Ser79)), ACC and glucose transporter 1 (GLUT1) in placenta between the three groups. The mRNA levels of Cav-1, AMPKα, ACC and GLUT1 in placenta were measured by real time-PCR. In the GDMM placenta group, both protein and mRNA levels of Cav-1 were down-regulated, while GLUT1 was up-regulated; the phosphorylation and mRNA levels of ACC and AMPKα were decreased, but total ACC protein levels were increased compared to both the GDMN (pmacrosomias have more severe inhibition of Cav-1 expression in placenta. Cav-1 is associated with placental glucose and fatty acid transport via the induction of AMPK signaling pathway and the reduction of GLUT1 signaling pathway to reverse GDM-induced macrosomia.

  1. Transport of alpha- and beta-D-glucose by the intact human red cell

    Energy Technology Data Exchange (ETDEWEB)

    Carruthers, A.; Melchior, D.L.

    1985-07-16

    The kinetics of alpha- and beta-D-glucose mutarotation and the transport of these anomers by intact human red cells were determined at 0.6 and 36.6 degrees C. The mutarotation coefficients for alpha- and beta-D-glucose in cell-free tris(hydroxymethyl)aminomethane medium (pH 7.4) at 0.6 degrees C are (2.25 +/- 0.2) and (1.73 +/- 0.42) X 10(-3) min-1, respectively, and at 36.6 degrees C are (69 +/- 12) and (75 +/- 5) X 10(-3) min-1, respectively. These values are in good agreement with previous estimates. At 0.6 degrees C, the red cell contains no detectable mutarotase activity. Initial rates of sugar uptake were measured by using radiolabeled D-glucose and time courses of uptake by turbidimetry. The time courses of alpha- and beta-D-glucose and an equilibrium mixture of alpha- and beta-D-glucose infinite-cis entry are identical at 0.66 degrees C (n = 41) where negligible mutarotation is observed. The apparent Ki values for inhibition of radiolabeled D-glucose initial uptake by unlabeled alpha- or beta-D-glucose at 0.6 degrees C are identical (1.6 mM). The calculated Vmax parameters for uptake of the radiolabeled anomers at this temperature are also indistinguishable. The time courses of infinite-cis alpha- and beta-D-glucose uptake at 36.66 degrees C are identical (n = 40). While D-glucose mutarotation is more rapid at this temperature, the anomers of D-glucose are not transported differently by the red cell hexose transfer system.

  2. Effect of diet on insulin binding and glucose transport in rat sarcolemmal vesicles

    International Nuclear Information System (INIS)

    Grimditch, G.K.; Barnard, R.J.; Sternlicht, E.; Whitson, R.H.; Kaplan, S.A.

    1987-01-01

    The purpose of this study was to compare the effects of a high-fat, high-sucrose diet (HFS) and a low-fat, high-complex carbohydrate diet (LFC) on glucose tolerance, insulin binding, and glucose transport in rat skeletal muscle. During the intravenous glucose tolerance test, peak glucose values at 5 min were significantly higher in the HFS group; 0-, 20-, and 60-min values were similar. Insulin values were significantly higher in the HFS group at all time points (except 60 min), indicating whole-body insulin resistance. Skeletal muscle was responsible, in part, for this insulin resistance, because specific D-glucose transport in isolated sarcolemmal (SL) vesicles under basal conditions was similar between LFC and HFS rats, despite the higher plasma insulin levels. Scatchard analyses of insulin binding curves to sarcolemmal vesicles revealed that the K/sub a/ of the high-affinity binding sites was significantly reduced by the HFS diet; no other binding changes were noted. Specific D-glucose transport in SL vesicles after maximum insulin stimulation (1 U/kg) was significantly depressed in the HFS group, indicating that HFS feeding also caused a postbinding defect. These results indicate that the insulin resistance in skeletal muscle associated with a HFS diet is due to both a decrease in the K/sub a/ of the high-affinity insulin receptors and a postbinding defect

  3. Decreased insulin action on muscle glucose transport after eccentric contractions in rats

    DEFF Research Database (Denmark)

    Asp, S; Richter, Erik

    1996-01-01

    We have recently shown that eccentric contractions (Ecc) of rat calf muscles cause muscle damage and decreased glycogen and glucose transporter GLUT-4 protein content in the white (WG) and red gastrocnemius (RG) but not in the soleus (S) (S. Asp, S. Kristiansen, and E. A. Richter. J. Appl. Physiol....... 79: 1338-1345, 1995). To study whether these changes affect insulin action, hindlimbs were perfused at three different insulin concentrations (0, 200, and 20,000 microU/ml) 2 days after one-legged eccentric contractions of the calf muscles. Compared with control, basal glucose transport was slightly...... velocity of glycogen synthase increased similarly with increasing insulin concentrations in Ecc- and control WG and RG. We conclude that insulin action on glucose transport but not glycogen synthase activity is impaired in perfused muscle exposed to prior eccentric contractions....

  4. Is contraction-stimulated glucose transport feedforward regulated by Ca2+?

    DEFF Research Database (Denmark)

    Jensen, Thomas Elbenhardt; Angin, Yeliz; Sylow, Lykke

    2014-01-01

    -stimulated glucose transport. A revised working model is proposed, in which muscle glucose transport during contraction is not directly regulated by SR Ca(2+) release but rather responds exclusively to feedback signals activated secondary to cross-bridge cycling and tension development.......In many cell types, Ca(2+) signals to increase the movement and surface membrane insertion of vesicles. In skeletal muscle, Ca(2+) is predominantly released from the sarcoplasmic reticulum (SR) to initiate contraction. Sarcoplasmic reticulum Ca(2+) release is widely believed to be a direct...... cell types. The literature is contrasted against our recent findings suggesting that SR Ca(2+) release is neither essential nor adequate to stimulate glucose transport in muscle. Instead, feedback signals through AMPK and mechanical stress are likely to account for most of contraction...

  5. GLUT-1 GLUCOSE TRANSPORTERS IN THE BLOOD-BRAIN BARRIER: DIFFERENTIAL PHOSPHORYLATION

    Science.gov (United States)

    Devraj, Kavi; Klinger, Marianne E.; Myers, Roland L.; Mokashi, Ashwini; Hawkins, Richard A.; Simpson, Ian A.

    2013-01-01

    Glucose is the primary metabolic fuel for the mammalian brain and a continuous supply is required to maintain normal CNS function. The transport of glucose across the blood-brain barrier (BBB) into the brain is mediated by the facilitative glucose transporter GLUT-1. Prior studies (Simpson et al. 2001) had revealed that the conformations of the GLUT-1 transporter were different in luminal (blood facing) and abluminal (brain facing) membranes of bovine cerebral endothelial cells, based on differential antibody recognition. In this study we have extended these observations and using a combination of 2D-PAGE/Western blotting and immunogold electron microscopy we determined that these different conformations are exhibited in vivo and arise from differential phosphorylation of GLUT-1 and not from alternative splicing or altered O- or N-linked glycosylation. PMID:21910135

  6. Evolutionary ancestry and novel functions of the mammalian glucose transporter (GLUT) family.

    Science.gov (United States)

    Wilson-O'Brien, Amy L; Patron, Nicola; Rogers, Suzanne

    2010-05-21

    In general, sugar porters function by proton-coupled symport or facilitative transport modes. Symporters, coupled to electrochemical energy, transport nutrients against a substrate gradient. Facilitative carriers transport sugars along a concentration gradient, thus transport is dependent upon extracellular nutrient levels. Across bacteria, fungi, unicellular non-vertebrates and plants, proton-coupled hexose symport is a crucial process supplying energy under conditions of nutrient flux. In mammals it has been assumed that evolution of whole body regulatory mechanisms would eliminate this need. To determine whether any isoforms bearing this function might be conserved in mammals, we investigated the relationship between the transporters of animals and the proton-coupled hexose symporters found in other species. We took a comparative genomic approach and have performed the first comprehensive and statistically supported phylogenetic analysis of all mammalian glucose transporter (GLUT) isoforms. Our data reveals the mammalian GLUT proteins segregate into five distinct classes. This evolutionary ancestry gives insight to structure, function and transport mechanisms within the groups. Combined with biological assays, we present novel evidence that, in response to changing nutrient availability and environmental pH, proton-coupled, active glucose symport function is maintained in mammalian cells. The analyses show the ancestry, evolutionary conservation and biological importance of the GLUT classes. These findings significantly extend our understanding of the evolution of mammalian glucose transport systems. They also reveal that mammals may have conserved an adaptive response to nutrient demand that would have important physiological implications to cell survival and growth.

  7. 4-acetoxyscirpendiol of Paecilomyces tenuipes inhibits Na(+)/D-glucose cotransporter expressed in Xenopus laevis oocytes.

    Science.gov (United States)

    Yoo, Ocki; Son, Joo-Hiuk; Lee, Dong-Hee

    2005-03-31

    Cordyceps, an entomopathogenic fungus, contains many health-promoting ingredients. Recent reports indicate that the consumption of cordyceps helps reduce blood-sugar content in diabetics. However, the mechanism underlying this reduction in circulatory sugar content is not fully understood. Methanolic extracts were prepared from the fruiting bodies of Paecilomyces tenuipes, and 4-beta acetoxyscirpendiol (4-ASD) was eventually isolated and purified. Na(+)/Glucose transporter-1 (SGLT-1) was expressed in Xenopus oocytes, and the effect of 4-ASD on SGLT-1 was analyzed utilizing a voltage clamp and by performing 2-deoxy-D-glucose (2-DOG) uptake studies. 4-ASD was shown to significantly inhibit SGLT-1 activity compared to the non-treated control in a dose-dependent manner. In the presence of the derivatives of 4-ASD (diacetoxyscirpenol or 15-acetoxyscirpendiol), SGLT-1 activity was greatly inhibited in an 4-ASD-like manner. Of these derivatives, 15-acetoxyscirepenol inhibited SGLT-1 as well as 4-ASD, whereas diacetoxyscirpenol was slightly less effective. Taken together, these results strongly indicate that 4-ASD in P. tenuipes may lower blood sugar levels in the circulatory system. We conclude that 4-ASD and its derivatives are effective SGLT-1 inhibitors.

  8. The Effect of Selenium Supplementation on Glucose Homeostasis and the Expression of Genes Related to Glucose Metabolism

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    Ewa Jablonska

    2016-12-01

    Full Text Available The aim of the study was to evaluate the effect of selenium supplementation on the expression of genes associated with glucose metabolism in humans, in order to explain the unclear relationship between selenium and the risk of diabetes. For gene expression analysis we used archival samples of cDNA from 76 non-diabetic subjects supplemented with selenium in the previous study. The supplementation period was six weeks and the daily dose of selenium was 200 µg (as selenium yeast. Blood for mRNA isolation was collected at four time points: before supplementation, after two and four weeks of supplementation, and after four weeks of washout. The analysis included 15 genes encoding selected proteins involved in insulin signaling and glucose metabolism. In addition, HbA1c and fasting plasma glucose were measured at three and four time points, respectively. Selenium supplementation was associated with a significantly decreased level of HbA1c but not fasting plasma glucose (FPG and significant down-regulation of seven genes: INSR, ADIPOR1, LDHA, PDHA, PDHB, MYC, and HIF1AN. These results suggest that selenium may affect glycemic control at different levels of regulation, linked to insulin signaling, glycolysis, and pyruvate metabolism. Further research is needed to investigate mechanisms of such transcriptional regulation and its potential implication in direct metabolic effects.

  9. Validation of 123I-6-deoxy-6-iodo-D-glucose (6-DIC) as tracer for the in-vivo glucose transport

    International Nuclear Information System (INIS)

    Perret, P.; Ghezzi, C.; Mathieu, J.P.; Morin, C.; Vidal, M.; Comet, M.; Fagret, D.

    1997-01-01

    The evaluation of the glucose transport is very important clinically because alterations of this transport were described in numerous pathologies, in neurology, oncology and endocrinology. A new analog of the 123 I-labelled has been synthesized: 123 I-6-deoxy-6-iodo-D-glucose (6-DIG). Its in-vitro biological behaviour is similar to that of 3-O-methyl-D-glucose (3-OMG), the reference tracer of glucose transport. The aim of the study was to determine if it is possible to make evident by 6-DIG a variations of in-vivo glucose transport. The studies were effected on a model of homozygote mice (db/db), genetically diabetic (NIDDM), presenting a severe insulin-resistance, characterized by deficient glucose transport in response to insulin. The studies of 6-DIG biodistribution (5 nmol/mouse) with (1.5 UI/Kg) or without exogenous insulin, were conducted in diabetic mice (db/db) and in non-diabetic (db/+) control mice. The results show that the capture of 6-DIG, as well as that of glucose, increases (by 30%) in response to insulin in most of insulin-sensitive tissues in control mice. In the insulin-resistant and hyperglycemic db/db mouse, the capture of 6-DIG is not modified, no matter whether the exogenous insulin is present. In conclusion, the 6-DIG is able to make evident a lack of glucose transport in heart, diaphragm and skeletal muscle in diabetic mouse and a physiological variation of this transport in response to insulin, in the control mouse. This result should be stressed because for the first time it is possible to evidence in-vivo variations into glucose transport with a iodated molecule

  10. Mammary alveolar cell as evaluation system for casein gene expression involved in glucose level

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    Young Tae Heo

    2017-06-01

    Full Text Available Objective Glucose is an essential fuel in the energy metabolism and synthesis pathways of all mammalian cells. In lactating animals, glucose is the major precursor for lactose and is a substrate for the synthesis of milk proteins and fat in mammary secretory (alveolar epithelial cells. However, clear utilization of glucose in mammary cells during lactogenesis is still unknown, due to the lack of in vitro analyzing models. Therefore, the objective of this study was to test the reliability of the mammary alveolar (MAC-T cell as an in vitro study model for glucose metabolism and lactating system. Methods Undifferentiated MAC-T cells were cultured in three types of Dulbecco’s modified Eagle’s medium with varying levels of glucose (no-glucose: 0 g/L, low-glucose: 1 g/L, and high-glucose: 4.5 g/L for 8 d, after which differentiation to casein secretion was induced. Cell proliferation and expression levels of apoptotic genes, Insulin like growth factor-1 (IGF1 receptor, oxytocin receptor, αS1, αS2, and β casein genes were analyzed at 1, 2, 4, and 8 d after differentiation. Results The proliferation of MAC-T cells with high-glucose treatment was seen to be significantly higher. Expression of apoptotic genes was not affected in any group. However, expression levels of the mammary development related gene (IGF1 receptor and lactation related gene (oxytocin receptor were significantly higher in the low-glucose group. Expressions of αS1-casein, αS2-casein, and β-casein were also higher in the low-glucose treated group as compared to that in the no-glucose and high-glucose groups. Conclusion The results demonstrated that although a high-glucose environment increases cell proliferation in MAC-T cells, a low-glucose treatment to MAC-T cells induces higher expression of casein genes. Our results suggest that the MAC-T cells may be used as an in vitro model to analyze mammary cell development and lactation connected with precise biological effects.

  11. Evidence for the involvement of Ala 166 in coupling Na(+) to sugar transport through the human Na(+)/glucose cotransporter

    DEFF Research Database (Denmark)

    Meinild, A K; Loo, D D; Hirayama, B A

    2001-01-01

    . The affinity for Na(+) was unchanged compared to that of hSGLT1, whereas the sugar affinity was reduced and sugar specificity was altered. There was a reduction in the turnover rate of the transporter, and in contrast to that of hSGLT1, the turnover rate depended on the sugar molecule. Exposure of A166C......We mutated residue 166, located in the putative Na(+) transport pathway between transmembrane segments 4 and 5 of human Na(+)/glucose cotransporter (hSGLT1), from alanine to cysteine (A166C). A166C was expressed in Xenopus laevis oocytes, and electrophysiological methods were used to assay function...... to MTSEA and MTSET, but not MTSES, abolished sugar transport. Accessibility of A166C to alkylating reagents was independent of protein conformation, indicating that the residue is always accessible from the extracellular surface. Sugar and phlorizin did not protect the residue from being alkylated...

  12. Ontogenic Changes of Villus Growth, Lactase Activity, and Intestinal Glucose Transporters in Preterm and Term Born Calves with or without Prolonged Colostrum Feeding.

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    Julia Steinhoff-Wagner

    Full Text Available Oral glucose supply is important for neonatal calves to stabilize postnatal plasma glucose concentration. The objective of this study was to investigate ontogenic development of small intestinal growth, lactase activity, and glucose transporter in calves (n = 7 per group that were born either preterm (PT; delivered by section 9 d before term or at term (T; spontaneous vaginal delivery or spontaneously born and fed colostrum for 4 days (TC. Tissue samples from duodenum and proximal, mid, and distal jejunum were taken to measure villus size and crypt depth, protein concentration of mucosa and brush border membrane vesicles (BBMV, total DNA and RNA concentration of mucosa, mRNA expression and activity of lactase, and mRNA expression of sodium-dependent glucose co-transporter-1 (SGLT1 and facilitative glucose transporter 2 (GLUT2 in mucosal tissue. Additionally, protein expression of SGLT1 in BBMV and GLUT2 in crude mucosal membranes and immunochemical localization of GLUT2 in the enterocytes were determined. Villus height in distal jejunum was lower in TC than in T. Crypt depth in all segments was largest and the villus height/crypt depth ratio in jejunum was smallest in TC calves. Concentration of RNA was highest in duodenal mucosa of TC calves, but neither lactase mRNA and activity nor SGLT1 and GLUT2 mRNA and protein expression differed among groups. Localization of GLUT2 in the apical membrane was greater, whereas in the basolateral membrane was lower in TC than in T and PT calves. Our study indicates maturation processes after birth for mucosal growth and trafficking of GLUT2 from the basolateral to the apical membrane. Minor differences of mucosal growth, lactase activity, and intestinal glucose transporters were seen between PT and T calves, pointing at the importance of postnatal maturation and feeding for mucosal growth and GLUT2 trafficking.

  13. Effects of glucose availability on expression of the key genes involved in synthesis of milk fat, lactose and glucose metabolism in bovine mammary epithelial cells.

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    Hongyun Liu

    Full Text Available As the main precursor for lactose synthesis, large amounts of glucose are required by lactating dairy cows. Milk yield greatly depends on mammary lactose synthesis due to its osmoregulatory property for mammary uptake of water. Thus, glucose availability to the mammary gland could be a potential regulator of milk production. In the present study, the effect of glucose availability on expression of the key genes involved in synthesis of milk fat, lactose and glucose metabolism in vitro was investigated. Bovine mammary epithelial cells (BMEC were treated for 12 h with various concentrations of glucose (2.5, 5, 10 or 20 mmol/L. The higher concentrations of glucose (10-20 mmol/L did not affect the mRNA expression of acetyl-CoA carboxylase, diacyl glycerol acyl transferase, glycerol-3 phosphate acyl transferase and α-lactalbumin, whereas fatty acid synthase, sterol regulatory element binding protein-1 and beta-1, 4-galactosyl transferase mRNA expression increased at 10 mmol/L and then decreased at 20 mmol/L. The content of lactose synthase increased with increasing concentration of glucose, with addition of highest value at 20 mmol/L of glucose. Moreover, the increased glucose concentration stimulated the activities of pyruvate kinase and glucose-6-phosphate dehydrogenase, and elevated the energy status of the BMEC. Therefore, it was deduced that after increasing glucose availability, the extra absorbed glucose was partitioned to entering the synthesis of milk fat and lactose by the regulation of the mRNA expression of key genes, promoting glucose metabolism by glycolysis and pentose phosphate pathway as well as energy status. These results indicated that the sufficient availability of glucose in BMEC may promote glucose metabolism, and affect the synthesis of milk composition.

  14. Crystal structure of a bacterial homologue of glucose transporters GLUT1-4.

    Science.gov (United States)

    Sun, Linfeng; Zeng, Xin; Yan, Chuangye; Sun, Xiuyun; Gong, Xinqi; Rao, Yu; Yan, Nieng

    2012-10-18

    Glucose transporters are essential for metabolism of glucose in cells of diverse organisms from microbes to humans, exemplified by the disease-related human proteins GLUT1, 2, 3 and 4. Despite rigorous efforts, the structural information for GLUT1-4 or their homologues remains largely unknown. Here we report three related crystal structures of XylE, an Escherichia coli homologue of GLUT1-4, in complex with d-xylose, d-glucose and 6-bromo-6-deoxy-D-glucose, at resolutions of 2.8, 2.9 and 2.6 Å, respectively. The structure consists of a typical major facilitator superfamily fold of 12 transmembrane segments and a unique intracellular four-helix domain. XylE was captured in an outward-facing, partly occluded conformation. Most of the important amino acids responsible for recognition of D-xylose or d-glucose are invariant in GLUT1-4, suggesting functional and mechanistic conservations. Structure-based modelling of GLUT1-4 allows mapping and interpretation of disease-related mutations. The structural and biochemical information reported here constitutes an important framework for mechanistic understanding of glucose transporters and sugar porters in general.

  15. Expression and knockdown analysis of glucose phosphate isomerase in chicken primordial germ cells.

    Science.gov (United States)

    Rengaraj, Deivendran; Lee, Sang In; Yoo, Min; Kim, Tae Hyun; Song, Gwonhwa; Han, Jae Yong

    2012-09-01

    Glucose is an important monosaccharide required to generate energy in all cells. After entry into cells, glucose is phosphorylated to glucose-6-phosphate and then transformed into glycogen or metabolized to produce energy. Glucose phosphate isomerase (GPI) catalyzes the reversible isomerization of glucose-6-phosphate and fructose-6-phosphate. Without GPI activity or fructose-6-phosphate, many steps of glucose metabolism would not occur. The requirement for GPI activity for normal functioning of primordial germ cells (PGCs) needs to be identified. In this study, we first examined the expression of chicken GPI during early embryonic development and germ cell development. GPI expression was strongly and ubiquitously detected in chicken early embryos and embryonic tissues at Embryonic Day 6.5 (E6.5). Continuous GPI expression was detected in PGCs and germ cells of both sexes during gonadal development. Specifically, GPI expression was stronger in male germ cells than in female germ cells during embryonic development and the majority of post-hatching development. Then, we used siRNA-1499 to knock down GPI expression in PGCs. siRNA-1499 caused an 85% knockdown in GPI, and PGC proliferation was also affected 48 h after transfection. We further examined the knockdown effects on 28 genes related to the glycolysis/gluconeogenesis pathway and the endogenous glucose level in chicken PGCs. Among genes related to glycolysis/gluconeogenesis, 20 genes showed approximately 3-fold lower expression, 4 showed approximately 10-fold lower, and 2 showed approximately 100-fold lower expression in knockdown PGCs. The endogenous glucose level was significantly reduced in knockdown PGCs. We conclude that the GPI gene is crucial for maintaining glycolysis and supplying energy to developing PGCs.

  16. Changes in hippocampal synaptic functions and protein expression in monosodium glutamate-treated obese mice during development of glucose intolerance.

    Science.gov (United States)

    Sasaki-Hamada, Sachie; Hojo, Yuki; Koyama, Hajime; Otsuka, Hayuma; Oka, Jun-Ichiro

    2015-05-01

    Glucose is the sole neural fuel for the brain and is essential for cognitive function. Abnormalities in glucose tolerance may be associated with impairments in cognitive function. Experimental obese model mice can be generated by an intraperitoneal injection of monosodium glutamate (MSG; 2 mg/g) once a day for 5 days from 1 day after birth. MSG-treated mice have been shown to develop glucose intolerance and exhibit chronic neuroendocrine dysfunction associated with marked cognitive malfunctions at 28-29  weeks old. Although hippocampal synaptic plasticity is impaired in MSG-treated mice, changes in synaptic transmission remain unknown. Here, we investigated whether glucose intolerance influenced cognitive function, synaptic properties and protein expression in the hippocampus. We demonstrated that MSG-treated mice developed glucose intolerance due to an impairment in the effectiveness of insulin actions, and showed cognitive impairments in the Y-maze test. Moreover, long-term potentiation (LTP) at Schaffer collateral-CA1 pyramidal synapses in hippocampal slices was impaired, and the relationship between the slope of extracellular field excitatory postsynaptic potential and stimulus intensity of synaptic transmission was weaker in MSG-treated mice. The protein levels of vesicular glutamate transporter 1 and GluA1 glutamate receptor subunits decreased in the CA1 region of MSG-treated mice. These results suggest that deficits in glutamatergic presynapses as well as postsynapses lead to impaired synaptic plasticity in MSG-treated mice during the development of glucose intolerance, though it remains unknown whether impaired LTP is due to altered inhibitory transmission. It may be important to examine changes in glucose tolerance in order to prevent cognitive malfunctions associated with diabetes. © 2015 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  17. Green and Chamomile Teas, but not Acarbose, Attenuate Glucose and Fructose Transport via Inhibition of GLUT2 and GLUT5.

    Science.gov (United States)

    Villa-Rodriguez, Jose A; Aydin, Ebru; Gauer, Julia S; Pyner, Alison; Williamson, Gary; Kerimi, Asimina

    2017-12-01

    High glycaemic sugars result in blood-glucose spikes, while large doses of post-prandial fructose inundate the liver, causing an imbalance in energy metabolism, both leading to increased risk of metabolic malfunction and type 2 diabetes. Acarbose, used for diabetes management, reduces post-prandial hyperglycaemia by delaying carbohydrate digestion. Chamomile and green teas both inhibited digestive enzymes (α-amylase and maltase) related to intestinal sugar release, as already established for acarbose. However, acarbose had no effect on uptake of sugars using both differentiated human Caco-2 cell monolayers and Xenopus oocytes expressing human glucose transporter-2 (GLUT2) and GLUT5. Both teas effectively inhibited transport of fructose and glucose through GLUT2 inhibition, while chamomile tea also inhibited GLUT5. Long term incubation of Caco-2/TC7 cells with chamomile tea for 16 h or 4 days did not enhance the observed effects, indicating that inhibition is acute. Sucrase activity was directly inhibited by green tea and acarbose, but not chamomile. These findings show that chamomile and green teas are potential tools to manage absorption and metabolism of sugars with efficacy against high sugar bolus stress inflicted, for example, by high fructose syrups, where the drug acarbose would be ineffective. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Expression and Location of Glucose-regulated Protein 78 in Testis and Epididymis

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    W Wang

    2014-04-01

    Full Text Available Objective: To know the role of glucose-regulated protein 78 (GRP78/BiP/HSPA5 in spermatogenesis and its expression and location in the testis and epididymis. Methods: Immunohistochemistry and Western blot were used to detect GRP78 location and expression in the testis and epididymis. Results: Glucose-regulated protein 78 was observed in spermatocytes, round spermatids and interstitial cells of the testis and in principal cells of the epididymis. Glucose-regulated protein 78 was first detected in the rat testis at postnatal day 14. Thereafter, the protein level increased gradually with age and was maintained at a high and stable state after postnatal day 28. In the rat, GRP78 was expressed in the principal cells but not in clear cells of the epididymis. Conclusion: Glucose-regulated protein 78 participates in the process of spermatogenesis.

  19. High Glucose Predisposes Gene Expression and ERK Phosphorylation to Apoptosis and Impaired Glucose-Stimulated Insulin Secretion via the Cytoskeleton

    Science.gov (United States)

    Yeo, Ronne Wee Yeh; Yang, Kaiyuan; Li, GuoDong; Lim, Sai Kiang

    2012-01-01

    Chronic high glucose (HG) inflicts glucotoxicity on vulnerable cell types such as pancreatic β cells and contributes to insulin resistance and impaired insulin secretion in diabetic patients. To identify HG-induced cellular aberrations that are candidate mediators of glucotoxicity in pancreatic β cells, we analyzed gene expression in ERoSHK6, a mouse insulin-secreting cell line after chronic HG exposure (six-day exposure to 33.3 mM glucose). Chronic HG exposure which reduced glucose-stimulated insulin secretion (GSIS) increased transcript levels of 185 genes that clustered primarily in 5 processes namely cellular growth and proliferation; cell death; cellular assembly and organization; cell morphology; and cell-to-cell signaling and interaction. The former two were validated by increased apoptosis of ERoSHK6 cells after chronic HG exposure and reaffirmed the vulnerability of β cells to glucotoxicity. The three remaining processes were partially substantiated by changes in cellular morphology and structure, and instigated an investigation of the cytoskeleton and cell-cell adhesion. These studies revealed a depolymerized actin cytoskeleton that lacked actin stress fibers anchored at vinculin-containing focal adhesion sites as well as loss of E-cadherin-mediated cell-cell adherence after exposure to chronic HG, and were concomitant with constitutive ERK1/2 phosphorylation that was refractory to serum and glucose deprivation. Although inhibition of ERK phosphorylation by PD98059 promoted actin polymerization, it increased apoptosis and GSIS impairment. These findings suggest that ERK phosphorylation is a proximate regulator of cellular processes targeted by chronic HG-induced gene expression and that dynamic actin polymerization and depolymerization is important in β cell survival and function. Therefore, chronic HG alters gene expression and signal transduction to predispose the cytoskeleton towards apoptosis and GSIS impairment. PMID:23024780

  20. Effects of insulin and epinephrine on Na+-K+ and glucose transport in soleus muscle

    International Nuclear Information System (INIS)

    Clausen, T.; Flatman, J.A.

    1987-01-01

    To identify possible cause-effect relationships between changes in active Na + -K + transport, resting membrane potential, and glucose transport, the effects of insulin and epinephrine were compared in rat soleus muscle. Epinephrine, which produced twice as large a hyperpolarization as insulin, induced only a modest increase in 14 C-labeled sugar transport. Ouabain, at a concentration (10 -3 M) sufficient to block active Na + -K + transport and the hyperpolarization induced by the two hormones, did not interfere with sugar transport stimulation. After Na + loading in K + -free buffer, the return to K + -containing standard buffer caused marked stimulation of active 22 Na + - 42 K + transport, twice the hyperpolarization produced by insulin but no change in sugar transport. The insulin-induced activation of the 22 Na + - 42 K + pump leads to decreased intracellular 22 Na + concentration and hyperpolarization, but none of these events can account for the concomitant activation of the glucose transport system. The stimulating effect of insulin on active Na + -K + transport was not suppressed by amiloride, indicating that in intact skeletal muscle it is not elicited by a primary increase in Na + influx via the Na + /H + -exchange system

  1. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport.

    Science.gov (United States)

    Naftalin, Richard J; Cunningham, Philip; Afzal-Ahmed, Iram

    2004-06-01

    1 Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide galanin in human erythrocytes in vitro. 2 The potencies of nootropic drugs in opposing scopolamine-induced memory loss correlate with their potencies in antagonising pentobarbital inhibition of erythrocyte glucose transport in vitro (Paniracetam and levetiracetam, while antagonising pentobarbital action, also inhibit glucose transport. Analeptics like bemigride and methamphetamine are more potent inhibitors of glucose transport than antagonists of hypnotic action on glucose transport. 4 There are similarities between amino-acid sequences in human glucose transport protein isoform 1 (GLUT1) and the benzodiazepine-binding domains of GABAA (gamma amino butyric acid) receptor subunits. Mapped on a 3D template of GLUT1, these homologies suggest that the site of diazepam and piracetam interaction is a pocket outside the central hydrophilic pore region. 5 Nootropic pyrrolidone antagonism of hypnotic drug inhibition of glucose transport in vitro may be an analogue of TRH antagonism of galanin-induced narcosis.

  2. Individualizing Treatment Approaches for Epileptic Patients with Glucose Transporter Type1 (GLUT-1 Deficiency

    Directory of Open Access Journals (Sweden)

    Armond Daci

    2018-01-01

    Full Text Available Monogenic and polygenic mutations are important contributors in patients suffering from epilepsy, including metabolic epilepsies which are inborn errors of metabolism with a good respond to specific dietetic treatments. Heterozygous variation in solute carrier family 2, facilitated glucose transporter member 1 (SLC2A1 and mutations of the GLUT1/SLC2A2 gene results in the failure of glucose transport, which is related with a glucose type-1 transporter (GLUT1 deficiency syndrome (GLUT1DS. GLUT1 deficiency syndrome is a treatable disorder of glucose transport into the brain caused by a variety of mutations in the SLC2A1 gene which are the cause of different neurological disorders also with different types of epilepsy and related clinical phenotypes. Since patients continue to experience seizures due to a pharmacoresistance, an early clinical diagnosis associated with specific genetic testing in SLC2A1 pathogenic variants in clinical phenotypes could predict pure drug response and might improve safety and efficacy of treatment with the initiation of an alternative energy source including ketogenic or analog diets in such patients providing individualized strategy approaches.

  3. Decreased insulin action on muscle glucose transport after eccentric contractions in rats

    DEFF Research Database (Denmark)

    Asp, S; Richter, Erik

    1996-01-01

    We have recently shown that eccentric contractions (Ecc) of rat calf muscles cause muscle damage and decreased glycogen and glucose transporter GLUT-4 protein content in the white (WG) and red gastrocnemius (RG) but not in the soleus (S) (S. Asp, S. Kristiansen, and E. A. Richter. J. Appl. Physio...

  4. Fast evolutionary rates associated with functional loss in class I glucose transporters of Schistosoma mansoni

    Czech Academy of Sciences Publication Activity Database

    Cabezas-Cruz, A.; Valdés, James J.; Lancelot, J.; Pierce, R.J.

    2015-01-01

    Roč. 16, NOV 19 2015 (2015), s. 980 ISSN 1471-2164 R&D Projects: GA MŠk(CZ) EE2.3.30.0032 Institutional support: RVO:60077344 Keywords : Schistosoma mansoni * glucose transporters * transcriptional regulation * phylogen * biophysics Subject RIV: EI - Biotechnology ; Bionics Impact factor: 3.867, year: 2015

  5. Dissociation of insulin receptor phosphorylation and stimulation of glucose transport in BC3H-1 myocytes

    International Nuclear Information System (INIS)

    Mojsilovic, L.P.; Standaert, M.L.; Rosic, N.K.; Pollet, R.J.

    1986-01-01

    The authors have investigated insulin receptor phosphorylation in differentiated cultured BC3H-1 myocytes. As for other insulin-responsive cell systems in partially purified wheat germ agglutinin receptor preparations, insulin stimulates the phosphorylation of its own receptor (95K β-subunits) in a dose dependent manner (0-400 nM), as identified by immunoprecipitation with antiinsulin receptor antibodies and SDS-PAGE. In the same preparations they show that 12-0-tetradecanyl phorbol acetate (TPA), which in many respect β-subunits in the same dose dependent manner (0-5 μM). In addition, antiinsulin receptor antibodies (B-10) also induced phosphorylation of mimics insulin action, also induced phosphorylation of the insulin receptor and HPLC tryptic maps of the 32 P-labeled β-subunit were identical to those for insulin-induced receptor phosphorylation. However, while insulin and TPA are potent stimulators of glucose transport in these muscle cells, the antireceptor antibodies alone failed to provoke glucose transport at any concentration. The specificity and activity of these antibodies were confirmed in their system by their ability to inhibit insulin binding and insulin-stimulated glucose transport in a concentration-dependent manner. Their results indicate that phosphorylation of insulin receptor is not a crucial event in mediating insulin action, at least with respect to glucose transport. While the effects of the B-10 antibody in the BC3H-1 myocyte differ from those in the adipocyte, their results provide independent confirmation of their essential conclusion that phosphorylation of the insulin receptor may not be necessary nor sufficient for its acute action in promoting glucose transport

  6. Role of Akt substrate of 160 kDa in insulin-stimulated and contraction-stimulated glucose transport

    DEFF Research Database (Denmark)

    Cartee, Gregory D; Wojtaszewski, Jørgen F P

    2007-01-01

    160 phosphorylation in skeletal muscle. Available data from skeletal muscle support the concepts developed in adipocytes with regard to the role AS160 plays in the regulation of insulin-stimulated glucose transport. In vivo exercise, in vitro contractions, or in situ contractions can also stimulate AS......Insulin and exercise, the most important physiological stimuli to increase glucose transport in skeletal muscle, trigger a redistribution of GLUT4 glucose transporter proteins from the cell interior to the cell surface, thereby increasing glucose transport capacity. The most distal insulin...... signaling protein that has been linked to GLUT4 translocation, Akt substrate of 160 kDa (AS160), becomes phosphorylated in insulin-stimulated 3T3-L1 adipocytes; this is important for insulin-stimulated GLUT4 translocation and glucose transport. Insulin also induces a rapid and dose-dependent increase in AS...

  7. UCP2 mRNA expression is dependent on glucose metabolism in pancreatic islets

    Energy Technology Data Exchange (ETDEWEB)

    Dalgaard, Louise T., E-mail: ltd@ruc.dk [Division of Endocrinology, Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA (United States); Department of Science, Systems and Models, Roskilde University (Denmark)

    2012-01-06

    Highlights: Black-Right-Pointing-Pointer UCP2 mRNA levels are decreased in islets of Langerhans from glucokinase deficient mice. Black-Right-Pointing-Pointer UCP2 mRNA up-regulation by glucose is dependent on glucokinase. Black-Right-Pointing-Pointer Absence of UCP2 increases GSIS of glucokinase heterozygous pancreatic islets. Black-Right-Pointing-Pointer This may protect glucokinase deficient mice from hyperglycemic damages. -- Abstract: Uncoupling Protein 2 (UCP2) is expressed in the pancreatic {beta}-cell, where it partially uncouples the mitochondrial proton gradient, decreasing both ATP-production and glucose-stimulated insulin secretion (GSIS). Increased glucose levels up-regulate UCP2 mRNA and protein levels, but the mechanism for UCP2 up-regulation in response to increased glucose is unknown. The aim was to examine the effects of glucokinase (GK) deficiency on UCP2 mRNA levels and to characterize the interaction between UCP2 and GK with regard to glucose-stimulated insulin secretion in pancreatic islets. UCP2 mRNA expression was reduced in GK+/- islets and GK heterozygosity prevented glucose-induced up-regulation of islet UCP2 mRNA. In contrast to UCP2 protein function UCP2 mRNA regulation was not dependent on superoxide generation, but rather on products of glucose metabolism, because MnTBAP, a superoxide dismutase mimetic, did not prevent the glucose-induced up-regulation of UCP2. Glucose-stimulated insulin secretion was increased in UCP2-/- and GK+/- islets compared with GK+/- islets and UCP2 deficiency improved glucose tolerance of GK+/- mice. Accordingly, UCP2 deficiency increased ATP-levels of GK+/- mice. Thus, the compensatory down-regulation of UCP2 is involved in preserving the insulin secretory capacity of GK mutant mice and might also be implicated in limiting disease progression in MODY2 patients.

  8. Transcriptional Modulation of Transport- and Metabolism-Associated Gene Clusters Leading to Utilization of Benzoate in Preference to Glucose in Pseudomonas putida CSV86.

    Science.gov (United States)

    Choudhary, Alpa; Modak, Arnab; Apte, Shree K; Phale, Prashant S

    2017-10-01

    The effective elimination of xenobiotic pollutants from the environment can be achieved by efficient degradation by microorganisms even in the presence of sugars or organic acids. Soil isolate Pseudomonas putida CSV86 displays a unique ability to utilize aromatic compounds prior to glucose. The draft genome and transcription analyses revealed that glucose uptake and benzoate transport and metabolism genes are clustered at the glc and ben loci, respectively, as two distinct operons. When grown on glucose plus benzoate, CSV86 displayed significantly higher expression of the ben locus in the first log phase and of the glc locus in the second log phase. Kinetics of substrate uptake and metabolism matched the transcription profiles. The inability of succinate to suppress benzoate transport and metabolism resulted in coutilization of succinate and benzoate. When challenged with succinate or benzoate, glucose-grown cells showed rapid reduction in glc locus transcription, glucose transport, and metabolic activity, with succinate being more effective at the functional level. Benzoate and succinate failed to interact with or inhibit the activities of glucose transport components or metabolic enzymes. The data suggest that succinate and benzoate suppress glucose transport and metabolism at the transcription level, enabling P. putida CSV86 to preferentially metabolize benzoate. This strain thus has the potential to be an ideal host to engineer diverse metabolic pathways for efficient bioremediation. IMPORTANCE Pseudomonas strains play an important role in carbon cycling in the environment and display a hierarchy in carbon utilization: organic acids first, followed by glucose, and aromatic substrates last. This limits their exploitation for bioremediation. This study demonstrates the substrate-dependent modulation of ben and glc operons in Pseudomonas putida CSV86, wherein benzoate suppresses glucose transport and metabolism at the transcription level, leading to preferential

  9. Evolutionary ancestry and novel functions of the mammalian glucose transporter (GLUT family

    Directory of Open Access Journals (Sweden)

    Patron Nicola

    2010-05-01

    Full Text Available Abstract Background In general, sugar porters function by proton-coupled symport or facilitative transport modes. Symporters, coupled to electrochemical energy, transport nutrients against a substrate gradient. Facilitative carriers transport sugars along a concentration gradient, thus transport is dependent upon extracellular nutrient levels. Across bacteria, fungi, unicellular non-vertebrates and plants, proton-coupled hexose symport is a crucial process supplying energy under conditions of nutrient flux. In mammals it has been assumed that evolution of whole body regulatory mechanisms would eliminate this need. To determine whether any isoforms bearing this function might be conserved in mammals, we investigated the relationship between the transporters of animals and the proton-coupled hexose symporters found in other species. Results We took a comparative genomic approach and have performed the first comprehensive and statistically supported phylogenetic analysis of all mammalian glucose transporter (GLUT isoforms. Our data reveals the mammalian GLUT proteins segregate into five distinct classes. This evolutionary ancestry gives insight to structure, function and transport mechanisms within the groups. Combined with biological assays, we present novel evidence that, in response to changing nutrient availability and environmental pH, proton-coupled, active glucose symport function is maintained in mammalian cells. Conclusions The analyses show the ancestry, evolutionary conservation and biological importance of the GLUT classes. These findings significantly extend our understanding of the evolution of mammalian glucose transport systems. They also reveal that mammals may have conserved an adaptive response to nutrient demand that would have important physiological implications to cell survival and growth.

  10. Prenatal Exposure to Sodium Arsenite Alters Placental Glucose 1, 3, and 4 Transporters in Balb/c Mice

    Science.gov (United States)

    Gutiérrez-Torres, Daniela Sarahí; González-Horta, Carmen; Del Razo, Luz María; Infante-Ramírez, Rocío; Ramos-Martínez, Ernesto; Levario-Carrillo, Margarita; Sánchez-Ramírez, Blanca

    2015-01-01

    Inorganic arsenic (iAs) exposure induces a decrease in glucose type 4 transporter (GLUT4) expression on the adipocyte membrane, which may be related to premature births and low birth weight infants in women exposed to iAs at reproductive age. The aim of this study was to analyze the effect of sodium arsenite (NaAsO2) exposure on GLUT1, GLUT3, and GLUT4 protein expression and on placental morphology. Female Balb/c mice (n = 15) were exposed to 0, 12, and 20 ppm of NaAsO2 in drinking water from 8th to 18th day of gestation. Morphological changes and GLUT1, GLUT3, and GLUT4 expression were evaluated in placentas by immunohistochemical and image analysis and correlated with iAs and arsenical species concentration, which were quantified by atomic absorption spectroscopy. NaAsO2 exposure induced a significant decrease in fetal and placental weight (P < 0.01) and increases in infarctions and vascular congestion. Whereas GLUT1 expression was unchanged in placentas from exposed group, GLUT3 expression was found increased. In contrast, GLUT4 expression was significantly lower (P < 0.05) in placentas from females exposed to 12 ppm. The decrease in placental GLUT4 expression might affect the provision of adequate fetal nutrition and explain the low fetal weight observed in the exposed groups. PMID:26339590

  11. Prenatal Exposure to Sodium Arsenite Alters Placental Glucose 1, 3, and 4 Transporters in Balb/c Mice

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    Daniela Sarahí Gutiérrez-Torres

    2015-01-01

    Full Text Available Inorganic arsenic (iAs exposure induces a decrease in glucose type 4 transporter (GLUT4 expression on the adipocyte membrane, which may be related to premature births and low birth weight infants in women exposed to iAs at reproductive age. The aim of this study was to analyze the effect of sodium arsenite (NaAsO2 exposure on GLUT1, GLUT3, and GLUT4 protein expression and on placental morphology. Female Balb/c mice (n=15 were exposed to 0, 12, and 20 ppm of NaAsO2 in drinking water from 8th to 18th day of gestation. Morphological changes and GLUT1, GLUT3, and GLUT4 expression were evaluated in placentas by immunohistochemical and image analysis and correlated with iAs and arsenical species concentration, which were quantified by atomic absorption spectroscopy. NaAsO2 exposure induced a significant decrease in fetal and placental weight (P<0.01 and increases in infarctions and vascular congestion. Whereas GLUT1 expression was unchanged in placentas from exposed group, GLUT3 expression was found increased. In contrast, GLUT4 expression was significantly lower (P<0.05 in placentas from females exposed to 12 ppm. The decrease in placental GLUT4 expression might affect the provision of adequate fetal nutrition and explain the low fetal weight observed in the exposed groups.

  12. Lack of SLC2A1 (glucose transporter 1) mutations in 30 Italian patients with alternating hemiplegia of childhood.

    Science.gov (United States)

    De Grandis, Elisa; Stagnaro, Michela; Biancheri, Roberta; Giannotta, Melania; Gobbi, Giuseppe; Traverso, Monica; Veneselli, Edvige; Zara, Federico

    2013-07-01

    Alternating hemiplegia of childhood is a rare, predominantly sporadic disorder. Diagnosis is clinical, and little is known about genetics. Glucose transporter 1 deficiency syndrome shares with alternating hemiplegia of childhood paroxysmal and nonparoxysmal symptoms. The aim of the study was to investigate glucose transporter 1 mutations in 30 Italian patients. Genetic material was analyzed by DNA amplification and glucose transporter 1 region sequencing. Mutational analysis findings of the SLC2A1 gene were negative in all patients. The pattern of movement disorders was reviewed. Interictal dystonia and multiple paroxysmal events were typical of alternating hemiplegia of childhood. In conclusion, alternating hemiplegia of childhood is a heterogeneous clinical condition, and although glucose transporter 1 deficiency can represent an undiagnosed cause of this disorder, mutational analysis is not routinely recommended. Alternatively, a careful clinical analysis and the 3-O-methyl-D-glucose uptake test can allow prompt identification of a subgroup of patients with alternating hemiplegia of childhood treatable with a ketogenic diet.

  13. Quantity of Na/K-ATPase and glucose transporters in the plasma membrane of rat adipocytes is reduced by in vivo triiodothyronine

    DEFF Research Database (Denmark)

    Voldstedlund, M.; Tranum-Jensen, Jørgen; Handberg, Aa.

    1995-01-01

    Anatomi, Na/K-ATPase, glucose transporters, adipocyt, immuno-gold labelling, electron microscopy......Anatomi, Na/K-ATPase, glucose transporters, adipocyt, immuno-gold labelling, electron microscopy...

  14. Interactions between co-expressed Arabidopsis sucrose transporters in the split-ubiquitin system

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    Lalonde Sylvie

    2003-03-01

    Full Text Available Abstract Background The Arabidopsis genome contains nine sucrose transporter paralogs falling into three clades: SUT1-like, SUT2 and SUT4. The carriers differ in their kinetic properties. Many transport proteins are known to exist as oligomers. The yeast-based split ubiquitin system can be used to analyze the ability of membrane proteins to interact. Results Promoter-GUS fusions were used to analyze the cellular expression of the three transporter genes in transgenic Arabidopsis plants. All three fusion genes are co-expressed in companion cells. Protein-protein interactions between Arabidopsis sucrose transporters were tested using the split ubiquitin system. Three paralogous sucrose transporters are capable of interacting as either homo- or heteromers. The interactions are specific, since a potassium channel and a glucose transporter did not show interaction with sucrose transporters. Also the biosynthetic and metabolizing enzymes, sucrose phosphate phosphatase and sucrose synthase, which were found to be at least in part bound to the plasma membrane, did not specifically interact with sucrose transporters. Conclusions The split-ubiquitin system provides a powerful tool to detect potential interactions between plant membrane proteins by heterologous expression in yeast, and can be used to screen for interactions with membrane proteins as baits. Like other membrane proteins, the Arabidopsis sucrose transporters are able to form oligomers. The biochemical approaches are required to confirm the in planta interaction.

  15. Accelerated alcoholic fermentation caused by defective gene expression related to glucose derepression in Saccharomyces cerevisiae.

    Science.gov (United States)

    Watanabe, Daisuke; Hashimoto, Naoya; Mizuno, Megumi; Zhou, Yan; Akao, Takeshi; Shimoi, Hitoshi

    2013-01-01

    Sake yeast strains maintain high fermentation rates, even after the stationary growth phase begins. To determine the molecular mechanisms underlying this advantageous brewing property, we compared the gene expression profiles of sake and laboratory yeast strains of Saccharomyces cerevisiae during the stationary growth phase. DNA microarray analysis revealed that the sake yeast strain examined had defects in expression of the genes related to glucose derepression mediated by transcription factors Adr1p and Cat8p. Furthermore, deletion of the ADR1 and CAT8 genes slightly but statistically significantly improved the fermentation rate of a laboratory yeast strain. We also identified two loss-of-function mutations in the ADR1 gene of existing sake yeast strains. Taken together, these results indicate that the gene expression program associated with glucose derepression for yeast acts as an impediment to effective alcoholic fermentation under glucose-rich fermentative conditions.

  16. The interaction of auraptene and other oxyprenylated phenylpropanoids with glucose transporter type 4.

    Science.gov (United States)

    Genovese, Salvatore; Ashida, Hitoshi; Yamashita, Yoko; Nakgano, Tomoya; Ikeda, Masaki; Daishi, Shirasaya; Epifano, Francesco; Taddeo, Vito Alessandro; Fiorito, Serena

    2017-08-15

    Glucose transporter 4 (GLUT4) is firmly established to play a pivotal role in glucose metabolism and in particular in modulating the insulin-stimulated glucose transport in several tissues, such as skeletal muscle and adipose tissue. Stimulation of GLUT4 by insulin results in its translocation to the plasma membrane, activation of several kinases, and finally in a large glucose influx into cells. In this study we investigated the modulating properties of four biologically active oxyprenylated ferulic acid and umbelliferone derivatives and of their unprenylated parent compounds on GLUT-4 mediated glucose uptake and translocation. Oxyprenylated phenylpropanoids have been synthesized in high yields and purity by already reported methodologies. All the synthesized chemicals were tested for their capacity to modulate GLUT4 mediated glucose uptake and GLUT4 translocation in L6 rat skeletal myoblasts in the concentration range 0.1 - 10 µM. Insulin (0.1 µM) was used as positive control. Western blot analysis was employed to assess if GLUT4 translocation occurred prior to increase of glucose uptake. Statistical analyses were carried out by the Dunnett multiple comparison test. 4'-Geranyloxyferulic acid (GOFA), 7-isopentenyloxycoumarin, and auraptene (7-geranyloxycoumarin) increased glucose uptake in a concentration-dependent manner, and significant increases were observed at 0.1 µM for GOFA, and 10 µM for 7-isopentenyloxycoumarin, and auraptene. These products also were able to significantly promote the translocation of GLUT4 to the plasma membrane of L6 myotubes. After treatment with compounds for 15 min, the incorporated amounts of GOFA, 7-isopentenyloxucoumarin, and auraptene were 0.15, 0.32, and 1.77 nmols/60-mm culture dish, respectively. A sample of raw Italian propolis, found to be rich in GOFA and auraptene, was also seen to mimic insulin-effect in the concentration range 0.01 - 1.0 mg/ml. Among the compounds assayed, auraptene showed to possess

  17. Temporal Changes in Cortical and Hippocampal Expression of Genes Important for Brain Glucose Metabolism Following Controlled Cortical Impact Injury in Mice

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    June Zhou

    2017-09-01

    Full Text Available Traumatic brain injury (TBI causes transient increases and subsequent decreases in brain glucose utilization. The underlying molecular pathways are orchestrated processes and poorly understood. In the current study, we determined temporal changes in cortical and hippocampal expression of genes important for brain glucose/lactate metabolism and the effect of a known neuroprotective drug telmisartan on the expression of these genes after experimental TBI. Adult male C57BL/6J mice (n = 6/group underwent sham or unilateral controlled cortical impact (CCI injury. Their ipsilateral and contralateral cortex and hippocampus were collected 6 h, 1, 3, 7, 14, 21, and 28 days after injury. Expressions of several genes important for brain glucose utilization were determined by qRT-PCR. In results, (1 mRNA levels of three key enzymes in glucose metabolism [hexo kinase (HK 1, pyruvate kinase, and pyruvate dehydrogenase (PDH] were all increased 6 h after injury in the contralateral cortex, followed by decreases at subsequent times in the ipsilateral cortex and hippocampus; (2 capillary glucose transporter Glut-1 mRNA increased, while neuronal glucose transporter Glut-3 mRNA decreased, at various times in the ipsilateral cortex and hippocampus; (3 astrocyte lactate transporter MCT-1 mRNA increased, whereas neuronal lactate transporter MCT-2 mRNA decreased in the ipsilateral cortex and hippocampus; (4 HK2 (an isoform of hexokinase expression increased at all time points in the ipsilateral cortex and hippocampus. GPR81 (lactate receptor mRNA increased at various time points in the ipsilateral cortex and hippocampus. These temporal alterations in gene expression corresponded closely to the patterns of impaired brain glucose utilization reported in both TBI patients and experimental TBI rodents. The observed changes in hippocampal gene expression were delayed and prolonged, when compared with those in the cortex. The patterns of alterations were specific

  18. Eugenosedin-A improves glucose metabolism and inhibits MAPKs expression in streptozotocin/nicotinamide-induced diabetic rats

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    Kuo-Ping Shen

    2018-03-01

    Full Text Available This study examined the effects of eugenosedin-A (Eu-A in a streptozotocin (STZ/nicotinamide-induced rat model of type II diabetes mellitus (T2DM. Six-week-old Sprague–Dawley rats were randomly divided into three groups: (1 RD group, normal rats fed a regular diet (RD, (2 DM group, T2DM rats fed a high-fat diet, and (3 Eu-A group, T2DM rats fed a high fat diet plus oral Eu-A (5 mg/kg/day. After 30 days, the DM group had higher body weight, higher blood glucose and lower insulin levels than the RD group. The DM group also had increased protein expression of glycogen synthase kinase (GSK in liver and skeletal muscle and decreased protein expression of insulin receptor (IR, insulin receptor substrate-1 (IRS-1, IRS-2, AMP-activated protein kinase (AMPK, glucose transporter-4 (GLUT-4, glucokinase (GCK, and peroxisome proliferator-activated receptor γ (PPAR-γ. STZ/nicotinamide-induced T2DM increased the expression of mitogen-activated protein kinases (MAPKs: p38, ERK, JNK and inflammatory p65 protein. In the Eu-A treated T2DM rats, however, blood glucose was attenuated and the insulin concentration stimulated. Changes in IR, IRS-1 and IRS-2 proteins as well as AMPK, GLUT-4, GCK, GSK, PPAR-γ, MAPKs, and inflammatory p65 proteins were ameliorated. These results suggested that Eu-A alleviates STZ/nicotinamide-induced hyperglycemia by improving insulin levels and glucose metabolism, and inhibiting the MAPKs- and p65-mediated inflammatory pathway.

  19. Role of glucose transporters in the intestinal absorption of gastrodin, a highly water-soluble drug with good oral bioavailability.

    Science.gov (United States)

    Cai, Zheng; Huang, Juan; Luo, Hui; Lei, Xiaolu; Yang, Zhaoxiang; Mai, Yang; Liu, Zhongqiu

    2013-07-01

    Gastrodin, a sedative drug, is a highly water-soluble phenolic glucoside with poor liposolubility but exhibits good oral bioavailability. The current study aims to investigate whether glucose transporters (GLTs) are involved in the intestinal absorption of gastrodin. The intestinal absorption kinetics of gastrodin was determined using the rat everted gut sac model, the Caco-2 cell culture model and the perfused rat intestinal model. In vivo pharmacokinetic studies using diabetic rats with high GLT expression were performed. Saturable intestinal absorption of gastrodin was observed in rat everted gut sacs. The apparent permeability (Papp) of gastrodin from the apical (A) to basolateral (B) side in Caco-2 cells was two-fold higher than that from B to A. Glucose or phlorizin, a sodium-dependent GLT (SGLT) inhibitor, reduced the absorption rates of gastrodin from perfused rat intestines. In vivo pharmacokinetic studies showed that the time of maximum plasma gastrodin concentration (Tmax) was prolonged from 28 to 72 min when orally co-administered with four times higher dose of glucose. However, the Tmax of gastrodin in diabetic rats was significantly lowered to 20 min because of the high intestinal SGLT1 level. In conclusion, our findings indicate that SGLT1 can facilitate the intestinal absorption of gastrodin.

  20. Radiation inactivation target size of rat adipocyte glucose transporters in the plasma membrane and intracellular pools

    International Nuclear Information System (INIS)

    Jacobs, D.B.; Berenski, C.J.; Spangler, R.A.; Jung, C.Y.

    1987-01-01

    The in situ assembly states of the glucose transport carrier protein in the plasma membrane and in the intracellular (microsomal) storage pool of rat adipocytes were assessed by studying radiation-induced inactivation of the D-glucose-sensitive cytochalasin B binding activities. High energy radiation inactivated the glucose-sensitive cytochalasin B binding of each of these membrane preparations by reducing the total number of the binding sites without affecting the dissociation constant. The reduction in total number of binding sites was analyzed as a function of radiation dose based on target theory, from which a radiation-sensitive mass (target size) was calculated. When the plasma membranes of insulin-treated adipocytes were used, a target size of approximately 58,000 daltons was obtained. For adipocyte microsomal membranes, we obtained target sizes of approximately 112,000 and 109,000 daltons prior to and after insulin treatment, respectively. In the case of microsomal membranes, however, inactivation data showed anomalously low radiation sensitivities at low radiation doses, which may be interpreted as indicating the presence of a radiation-sensitive inhibitor. These results suggest that the adipocyte glucose transporter occurs as a monomer in the plasma membrane while existing in the intracellular reserve pool either as a homodimer or as a stoichiometric complex with a protein of an approximately equal size

  1. Adenoviral-mediated placental gene transfer of IGF-1 corrects placental insufficiency via enhanced placental glucose transport mechanisms.

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    Helen N Jones

    Full Text Available Previous work in our laboratory demonstrated that over-expression of human insulin-like growth factor -1 (hIGF-1 in the placenta corrects fetal weight deficits in mouse, rat, and rabbit models of intrauterine growth restriction without changes in placental weight. The underlying mechanisms of this effect have not been elucidated. To investigate the effect of intra-placental IGF-1 over-expression on placental function we examined glucose transporter expression and localization in both a mouse model of IUGR and a model of human trophoblast, the BeWo Choriocarcinoma cell line.At gestational day 18, animals were divided into four groups; sham-operated controls, uterine artery branch ligation (UABL, UABL+Ad-hIGF-1 (10(8 PFU, UABL+Ad-LacZ (10(8 PFU. At gestational day 20, pups and placentas were harvested by C-section. For human studies, BeWo choriocarcinoma cells were grown in F12 complete medium +10%FBS. Cells were incubated in serum-free control media ± Ad-IGF-1 or Ad-LacZ for 48 hours. MOIs of 10∶1 and 100∶1 were utilized. The RNA, protein expression and localization of glucose transporters GLUT1, 3, 8, and 9 were analyzed by RT-PCR, Western blot and immunohistochemistry.In both the mouse placenta and BeWo, GLUT1 regulation was linked to altered protein localization. GLUT3, localized to the mouse fetal endothelial cells, was reduced in placental insufficiency but maintained with Ad-I GF-1 treatment. Interestingly, GLUT8 expression was reduced in the UABL placenta but up-regulated following Ad-IGF-1 in both mouse and human systems. GLUT9 expression in the mouse was increased by Ad-IGF-1 but this was not reflected in the BeWo, where Ad-IGF-1 caused moderate membrane relocalization.Enhanced GLUT isoform transporter expression and relocalization to the membrane may be an important mechanism in Ad-hIGF-1mediated correction of placental insufficiency.

  2. Empagliflozin and Kinetics of Renal Glucose Transport in Healthy Individuals and Individuals With Type 2 Diabetes.

    Science.gov (United States)

    Al-Jobori, Hussein; Daniele, Giuseppe; Cersosimo, Eugenio; Triplitt, Curtis; Mehta, Rucha; Norton, Luke; DeFronzo, Ralph A; Abdul-Ghani, Muhammad

    2017-07-01

    Renal glucose reabsorption was measured with the stepped hyperglycemic clamp in 15 subjects with type 2 diabetes mellitus (T2DM) and 15 without diabetes after 2 days and after more chronic (14 days) treatment with empagliflozin. Patients with T2DM had significantly greater maximal renal glucose transport (Tm G ) compared with subjects without diabetes at baseline (459 ± 53 vs. 337 ± 25 mg/min; P Empagliflozin treatment for 48 h reduced the Tm G in both individuals with and without diabetes by 44 ± 7 and 53 ± 6%, respectively (both P empagliflozin in both groups on day 14 (by 65 ± 5 and 75 ± 3%, respectively). Empagliflozin reduced the plasma glucose concentration threshold for glucose spillage in the urine similarly in individuals with T2DM and without diabetes to empagliflozin reduces both Tm G and threshold for glucose spillage in the urine in patients with T2DM and those without diabetes. © 2017 by the American Diabetes Association.

  3. The extent of co-metabolism of glucose and galactose by L. lactis changes with the expression of the lacSZ operon from Streptococcus thermophilus

    DEFF Research Database (Denmark)

    Solem, Christian; Købmann, Brian Jensen; Jensen, Peter Ruhdal

    2008-01-01

    The lactose transporter and β-galactosidase from Streptococcus thermophilus, encoded by the lacSZ operon, were introduced into the lactose-negative strain Lactococcus lactis MG1363 and the expression of the lacSZ operon was modulated by substitution of the native promoter with randomized synthetic...... promoters. A series of strains with various expression levels of lacSZ were examined for their fermentation of lactose. Strains with a high expression level were found to metabolize lactose in a similar manner to S. thermophilus, i.e. the galactose moiety of lactose was excreted to the growth medium...... and only glucose was metabolized in glycolysis. Interestingly, strains with low expression of the operon showed a mixed acid metabolism and co-metabolism of galactose and glucose. The lactose flux increased gradually with increasing expression of the lacSZ operon until an optimum was observed...

  4. Decreased muscle GLUT-4 and contraction-induced glucose transport after eccentric contractions

    DEFF Research Database (Denmark)

    Kristiansen, S; Asp, Svend; Richter, Erik

    1996-01-01

    Eccentric exercise causes muscle damage and decreased muscle glycogen and glucose transporter isoform (GLUT-4) protein content. We investigated whether the contraction-induced increase in skeletal muscle glucose transport and muscle performance is affected by prior eccentric contractions. The calf...... muscles from rats were stimulated for eccentric (EC) or concentric (CC) contractions or were passively stretched (ST). Muscles from unstimulated control (CT) rats were also studied. Two days later, all rats had their isolated hindlimbs perfused either at rest or during 15 min of isometric muscle...... contractions. EC rats had a significantly lower total GLUT-4 protein content in the white gastrocnemius (GW) muscle (55%) and red gastrocnemius (GR) muscle (34%) compared with muscle from the CT, ST, and CC rats. In contrast, GLUT-1 protein content was approximately twofold higher in the GW muscle in EC rats...

  5. Insulin binding and glucose transport in adipocytes of acarbose-treated Zucker lean and obese rats.

    Science.gov (United States)

    Vasselli, J R; Flory, T; Fried, S K

    1987-01-01

    The intestinal glucosidase inhibitor acarbose was administered as a dietary admix (30 mg/100 g chow diet) to male Zucker obese and lean rats. After 15 weeks, epidiymal fat pads were removed and adipocytes isolated by collagenase digestion. Equilibrium binding of A-14 tyrosine 125I-insulin, and transport of U-14C-glucose was determined was adipocytes incubated for 50 min at 37 degrees C in 0-16000 pM insulin. Insulin binding/cell was enhanced two-fold in lean (P less than 0.01) and obese (n.s.) drug groups. In drug-treated leans, increased sensitivity of glucose transport to submaximally stimulating concentrations of insulin was observed (P less than 0.02). For both genotypes, acarbose mildly decreased insulin levels and body weight gain, although adipocyte size was unaffected. Results indicate that enhanced insulin binding accompanies metabolic improvements induced by acarbose in lean Zucker rats.

  6. Euglycaemic diabetic ketoacidosis in patients using sodium-glucose co-transporter 2 inhibitors.

    Science.gov (United States)

    Isaacs, Michelle; Tonks, Katherine T; Greenfield, Jerry R

    2017-06-01

    Sodium-glucose co-transporter 2 inhibitors (SGLT2i) are an increasingly prescribed class of medication for type 2 diabetes mellitus. Euglycaemic diabetic ketoacidosis (euDKA) has been reported in association with SGLT2i use. Clinicians need to understand how to recognise and treat this complication. We describe three cases of euDKA in patients treated with SGLT2i. © 2017 Royal Australasian College of Physicians.

  7. Simultaneous fermentation of glucose and xylose at elevated temperatures co-produces ethanol and xylitol through overexpression of a xylose-specific transporter in engineered Kluyveromyces marxianus.

    Science.gov (United States)

    Zhang, Biao; Zhang, Jia; Wang, Dongmei; Han, Ruixiang; Ding, Rui; Gao, Xiaolian; Sun, Lianhong; Hong, Jiong

    2016-09-01

    Engineered Kluyveromyces marxianus strains were constructed through over-expression of various transporters for simultaneous co-fermentation of glucose and xylose. The glucose was converted into ethanol, whereas xylose was converted into xylitol which has higher value than ethanol. Over-expressing xylose-specific transporter ScGAL2-N376F mutant enabled yeast to co-ferment glucose and xylose and the co-fermentation ability was obviously improved through increasing ScGAL2-N376F expression. The production of glycerol was blocked and acetate production was reduced by disrupting gene KmGPD1. The obtained K. marxianus YZJ119 utilized 120g/L glucose and 60g/L xylose simultaneously and produced 50.10g/L ethanol and 55.88g/L xylitol at 42°C. The yield of xylitol from consumed xylose was over 98% (0.99g/g). Through simultaneous saccharification and co-fermentation at 42°C, YZJ119 produced a maximal concentration of 44.58g/L ethanol and 32.03g/L xylitol or 29.82g/L ethanol and 31.72g/L xylitol, respectively, from detoxified or non-detoxified diluted acid pretreated corncob. Copyright © 2016 Elsevier Ltd. All rights reserved.

  8. Glucocorticoids inhibit glucose transport and glutamate uptake in hippocampal astrocytes: implications for glucocorticoid neurotoxicity.

    Science.gov (United States)

    Virgin, C E; Ha, T P; Packan, D R; Tombaugh, G C; Yang, S H; Horner, H C; Sapolsky, R M

    1991-10-01

    Glucocorticoids (GCs), the adrenal steroid hormones secreted during stress, can damage the hippocampus and impair its capacity to survive coincident neurological insults. This GC endangerment of the hippocampus is energetic in nature, as it can be prevented when neurons are supplemented with additional energy substrates. This energetic endangerment might arise from the ability of GCs to inhibit glucose transport into both hippocampal neurons and astrocytes. The present study explores the GC inhibition in astrocytes. (1) GCs inhibited glucose transport approximately 15-30% in both primary and secondary hippocampal astrocyte cultures. (2) The parameters of inhibition agreed with the mechanisms of GC inhibition of glucose transport in peripheral tissues: A minimum of 4 h of GC exposure were required, and the effect was steroid specific (i.e., it was not triggered by estrogen, progesterone, or testosterone) and tissue specific (i.e., it was not triggered by GCs in cerebellar or cortical cultures). (3) Similar GC treatment caused a decrease in astrocyte survival during hypoglycemia and a decrease in the affinity of glutamate uptake. This latter observation suggests that GCs might impair the ability of astrocytes to aid neurons during times of neurologic crisis (i.e., by impairing their ability to remove damaging glutamate from the synapse).

  9. Apoptosis and changes in glucose transport early after treatment of Morris hepatoma with gemcitabine

    International Nuclear Information System (INIS)

    Haberkorn, U.; Bellemann, M.E.; Brix, G.; Kamencic, H.; Traut, U.; Kinscherf, R.; Doll, J.; Blatter, J.

    2001-01-01

    Apoptosis has been described as an energy-consuming process. This combined in vivo/in vitro study investigated the effects of the antineoplastic agent gemcitabine on tumour metabolism and on the induction of apoptosis. Dynamic positron emission tomography (PET) measurements of fluorine-18 fluorodeoxyglucose (FDG) uptake were done in rats bearing Morris hepatoma prior to and after therapy with 90 mg gemcitabine/kg b.w. Furthermore, thymidine (TdR) incorporation into the DNA of these tumours was determined. In vitro measurements of FDG and TdR uptake were performed immediately and 24 h after the end of gemcitabine treatment, and the amount of apoptotic cells was determined using the TUNEL reaction. In vivo an increase in FDG transport and phosphorylation occurred early after gemcitabine treatment, although TdR incorporation into the DNA of the tumours declined. In vitro, an enhanced glucose transport, an increase in TdR uptake in the cytoplasm and a decrease in TdR incorporation in the nucleic acid fraction early after treatment occurred. Inhibition of glucose transport caused an increase in the amount of apoptotic cells. The increase in glucose uptake and TdR metabolism early after therapy is interpreted as a stress reaction of the tumour cells, protecting the cells from apoptosis during this early period after exposure to cytotoxic drugs like gemcitabine. (orig.)

  10. Apoptosis and changes in glucose transport early after treatment of Morris hepatoma with gemcitabine

    Energy Technology Data Exchange (ETDEWEB)

    Haberkorn, U. [Heidelberg Univ. (Germany). Abt. fuer Klinische Nuklearmedizin; Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg (Germany); Bellemann, M.E. [Department of Biomedical Engineering, University of Applied Sciences, Jena (Germany); Brix, G. [Department of Medical Radiation Hygiene, Federal Office for Radiation Protection, Neuherberg (Germany); Kamencic, H.; Traut, U.; Kinscherf, R. [Heidelberg Univ. (Germany). Inst. fuer Anatomie und Zellbiologie; Morr, I.; Altmann, A. [Clinical Cooperation Unit Nuclear Medicine, German Cancer Research Center, Heidelberg (Germany); Doll, J. [Dept. of Medical Physics, German Cancer Research Center, Heidelberg (Germany); Blatter, J. [Lilly GmbH Germany, Bad Homburg (Germany)

    2001-04-01

    Apoptosis has been described as an energy-consuming process. This combined in vivo/in vitro study investigated the effects of the antineoplastic agent gemcitabine on tumour metabolism and on the induction of apoptosis. Dynamic positron emission tomography (PET) measurements of fluorine-18 fluorodeoxyglucose (FDG) uptake were done in rats bearing Morris hepatoma prior to and after therapy with 90 mg gemcitabine/kg b.w. Furthermore, thymidine (TdR) incorporation into the DNA of these tumours was determined. In vitro measurements of FDG and TdR uptake were performed immediately and 24 h after the end of gemcitabine treatment, and the amount of apoptotic cells was determined using the TUNEL reaction. In vivo an increase in FDG transport and phosphorylation occurred early after gemcitabine treatment, although TdR incorporation into the DNA of the tumours declined. In vitro, an enhanced glucose transport, an increase in TdR uptake in the cytoplasm and a decrease in TdR incorporation in the nucleic acid fraction early after treatment occurred. Inhibition of glucose transport caused an increase in the amount of apoptotic cells. The increase in glucose uptake and TdR metabolism early after therapy is interpreted as a stress reaction of the tumour cells, protecting the cells from apoptosis during this early period after exposure to cytotoxic drugs like gemcitabine. (orig.)

  11. Dissociation of in vitro sensitivities of glucose transport and antilipolysis to insulin in NIDDM

    International Nuclear Information System (INIS)

    Yki-Jaervinen, H.; Kubo, K.; Zawadzki, J.; Lillioja, S.; Young, A.; Abbott, W.; Foley, J.E.

    1987-01-01

    It is unclear from previous studies whether qualitative or only quantitative differences exist in insulin action in adipocytes obtained from obese subjects with non-insulin-dependent diabetes mellitus (NIDDM) when compared with equally obese nondiabetic subjects. In addition, the role of changes in insulin binding as a cause of insulin resistance in NIDDM is still controversial. The authors compared the sensitivities of [ 14 C]-glucose transport and antilipolysis to insulin and measured [ 125 I]-insulin binding in abdominal adipocytes obtained from 45 obese nondiabetic, obese diabetic, and 15 nonobese female southwestern American Indians. Compared with the nonobese group, the sensitivities of glucose transport antilipolysis were reduced in both the obese nondiabetic and obese diabetic groups. Compared with the obese nondiabetic subjects, the ED 50 for stimulation of glucose transport was higher in the obese patients with NIDDM. In contrast, the ED 50 S for antilipolysis were similar in obese diabetic patients and obese nondiabetic subjects. No differences was found in insulin binding in patients with NIDDM when compared with the equally obese nondiabetic subjects. These data indicate 1) the mechanism of insulin resistance differs in NIDDM and obesity, and 2) the selective loss of insulin sensitivity in NIDDM precludes changes in insulin binding as a cause of insulin resistance in this disorder

  12. High Glucose Represses hERG K+ Channel Expression through Trafficking Inhibition

    Directory of Open Access Journals (Sweden)

    Yuan-Qi Shi

    2015-08-01

    Full Text Available Background/Aims: Abnormal QT prolongation is the most prominent cardiac electrical disturbance in patients with diabetes mellitus (DM. It is well known that the human ether-ago-go-related gene (hERG controls the rapid delayed rectifier K+ current (IKr in cardiac cells. The expression of the hERG channel is severely down-regulated in diabetic hearts, and this down-regulation is a critical contributor to the slowing of repolarization and QT prolongation. However, the intracellular mechanisms underlying the diabetes-induced hERG deficiency remain unknown. Methods: The expression of the hERG channel was assessed via western blot analysis, and the hERG current was detected with a patch-clamp technique. Results: The results of our study revealed that the expression of the hERG protein and the hERG current were substantially decreased in high-glucose-treated hERG-HEK cells. Moreover, we demonstrated that the high-glucose-mediated damage to the hERG channel depended on the down-regulation of protein levels but not the alteration of channel kinetics. These discoveries indicated that high glucose likely disrupted hERG channel trafficking. From the western blot and immunoprecipitation analyses, we found that high glucose induced trafficking inhibition through an effect on the expression of Hsp90 and its interaction with hERG. Furthermore, the high-glucose-induced inhibition of hERG channel trafficking could activate the unfolded protein response (UPR by up-regulating the expression levels of activating transcription factor-6 (ATF-6 and the ER chaperone protein calnexin. In addition, we demonstrated that 100 nM insulin up-regulated the expression of the hERG channel and rescued the hERG channel repression caused by high glucose. Conclusion: The results of our study provide the first evidence of a high-glucose-induced hERG channel deficiency resulting from the inhibition of channel trafficking. Furthermore, insulin promotes the expression of the hERG channel

  13. Effect of Treadmill Exercise on Interleukin-15 Expression and Glucose Tolerance in Zucker Diabetic Fatty Rats

    Directory of Open Access Journals (Sweden)

    Hee-Jae Kim

    2013-10-01

    Full Text Available BackgroundInterleukin-15 (IL-15, a well-known myokine, is highly expressed in skeletal muscle and is involved in muscle-fat crosstalk. Recently, a role of skeletal muscle-derived IL-15 in the improvement of glucose homeostasis and insulin sensitivity has been proposed. However, little is known regarding the influence of endurance training on IL-15 expression in type 2 diabetic skeletal muscles. We investigated the effect of endurance exercise training on glucose tolerance and IL-15 expression in skeletal muscles using type 2 diabetic animal models.MethodsMale Zucker diabetic fatty (ZDF and ZDF lean control (ZLC rats were randomly divided into three groups: sedentary ZLC, sedentary ZDF (ZDF-Con, and exercised ZDF (ZDF-Ex. The ZDF-Ex rats were forced to run a motor-driven treadmill for 60 minutes once a day 5 times per week for 12 weeks. Intraperitoneal glucose tolerance test (IPGTT was performed after 12 weeks. Expression of IL-15 was measured using ELISA in extracted soleus (SOL and gastrocnemius medial muscles.ResultsAfter 12 weeks of treadmill training, reduction of body weight was observed in ZDF-Ex compared to ZDF-Con rats. Glucose tolerance using IPGTT in diabetic rats was significantly improved in ZDF-Ex rats. Furthermore, the expression of IL-15 was significantly increased (P<0.01 only in the SOL of ZDF-Ex rats compared to ZDF-Con. Additionally, IL-15 expression in SOL muscles was negatively correlated with change of body weight (R=-0.424, P=0.04.ConclusionThe present study results suggest that 12 weeks of progressive endurance training significantly improved glucose tolerance with concomitant increase of IL-15 expression in SOL muscles of type 2 diabetic rats.

  14. (+-Rutamarin as a dual inducer of both GLUT4 translocation and expression efficiently ameliorates glucose homeostasis in insulin-resistant mice.

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    Yu Zhang

    Full Text Available Glucose transporter 4 (GLUT4 is a principal glucose transporter in response to insulin, and impaired translocation or decreased expression of GLUT4 is believed to be one of the major pathological features of type 2 diabetes mellitus (T2DM. Therefore, induction of GLUT4 translocation or/and expression is a promising strategy for anti-T2DM drug discovery. Here we report that the natural product (+-Rutamarin (Rut functions as an efficient dual inducer on both insulin-induced GLUT4 translocation and expression. Rut-treated 3T3-L1 adipocytes exhibit efficiently enhanced insulin-induced glucose uptake, while diet-induced obese (DIO mice based assays further confirm the Rut-induced improvement of glucose homeostasis and insulin sensitivity in vivo. Subsequent investigation of Rut acting targets indicates that as a specific protein tyrosine phosphatase 1B (PTP1B inhibitor Rut induces basal GLUT4 translocation to some extent and largely enhances insulin-induced GLUT4 translocation through PI3 kinase-AKT/PKB pathway, while as an agonist of retinoid X receptor α (RXRα, Rut potently increases GLUT4 expression. Furthermore, by using molecular modeling and crystallographic approaches, the possible binding modes of Rut to these two targets have been also determined at atomic levels. All our results have thus highlighted the potential of Rut as both a valuable lead compound for anti-T2DM drug discovery and a promising chemical probe for GLUT4 associated pathways exploration.

  15. Proteomic screening of glucose-responsive and glucose non-reponsive MIN-6 beta cells reveals differential expression of protein involved in protein folding, secretion and oxidative stress

    DEFF Research Database (Denmark)

    Dowling, P.; O´Driscoll, L.; O´Sullivan, F.

    2006-01-01

    The glucose-sensitive insulin-secretion (GSIS) phenotype is relatively unstable in long-term culture of beta cells. The purpose of this study was to investigate relative changes in the proteome between glucose-responsive (low passage) and glucose non-responsive (high passage) murine MIN-6.......8%). From the differentially expressed proteins identified in this study, groups of proteins associated with the endoplasmic reticulum (ER) and proteins involved in oxidative stress were found to be significantly decreased in the high-passage (H passage) cells. These proteins included endoplasmic reticulum...... protein 29 (ERp29); 78-kDa glucose-related protein, (GRP78); 94-kDa glucose-related protein (GRP94); protein disulphide isomerase; carbonyl reductase 3; peroxidoxin 4 and superoxide dismutase 1. These results suggest that non-GSIS MIN-6 cells do not have the same ability/capacity of glucose-responsive MIN...

  16. Resveratrol Inhibits Porcine Intestinal Glucose and Alanine Transport: Potential Roles of Na+/K+-ATPase Activity, Protein Kinase A, AMP-Activated Protein Kinase and the Association of Selected Nutrient Transport Proteins with Detergent Resistant Membranes

    Directory of Open Access Journals (Sweden)

    Stefanie Klinger

    2018-03-01

    Full Text Available Background: Beneficial effects of Resveratrol (RSV have been demonstrated, including effects on transporters and channels. However, little is known about how RSV influences intestinal transport. The aim of this study was to further characterize the effects of RSV on intestinal transport and the respective mechanisms. Methods: Porcine jejunum and ileum were incubated with RSV (300 µM, 30 min in Ussing chambers (functional studies and tissue bathes (detection of protein expression, phosphorylation, association with detergent resistant membranes (DRMs. Results: RSV reduced alanine and glucose-induced short circuit currents (ΔIsc and influenced forskolin-induced ΔIsc. The phosphorylation of sodium–glucose-linked transporter 1 (SGLT1, AMP-activated protein kinase (AMPK, protein kinase A substrates (PKA-S and liver kinase B1 (LKB1 increased but a causative relation to the inhibitory effects could not directly be established. The DRM association of SGLT1, peptide transporter 1 (PEPT1 and (phosphorylated Na+/H+-exchanger 3 (NHE3 did not change. Conclusion: RSV influences the intestinal transport of glucose, alanine and chloride and is likely to affect other transport processes. As the effects of protein kinase activation vary between the intestinal localizations, it would appear that increasing cyclic adenosine monophosphate (cAMP levels are part of the mechanism. Nonetheless, the physiological responses depend on cell type-specific structures.

  17. The extent of co-metabolism of glucose and galactose by Lactococcus lactis changes with the expression of the lacSZ operon from Streptococcus thermophilus.

    Science.gov (United States)

    Solem, Christian; Koebmann, Brian; Jensen, Peter R

    2008-05-01

    The lactose transporter and beta-galactosidase from Streptococcus thermophilus, encoded by the lacSZ operon, were introduced into the lactose-negative strain Lactococcus lactis MG1363 and the expression of the lacSZ operon was modulated by substitution of the native promoter with randomized synthetic promoters. A series of strains with various expression levels of lacSZ were examined for their fermentation of lactose. Strains with a high expression level were found to metabolize lactose in a similar manner to S. thermophilus, i.e. the galactose moiety of lactose was excreted to the growth medium and only glucose was metabolized in glycolysis. Interestingly, strains with low expression of the operon showed a mixed acid metabolism and co-metabolism of galactose and glucose. The lactose flux increased gradually with increasing expression of the lacSZ operon until an optimum was observed at intermediate beta-galactosidase activities of 2000-3000 Miller units. At higher expression levels, the flux decreased. These strains had a glycolytic flux comparable with those of reference strains with the standard lactococcal PTS(lac) (lactose phosphotransferase transport system) lactose transporter, which indicates that lactose transport is not rate-limiting for glycolysis in Lactococcus. Finally, an additional ATP drain was introduced into the fastest growing strain, CS2004, to test whether the ATP demand controlled glycolysis under these conditions, but in fact no increase in glycolytic flux was observed.

  18. Effect of in vivo injection of cholera and pertussis toxin on glucose transport in rat skeletal muscle

    DEFF Research Database (Denmark)

    Ploug, Thorkil; Han, X; Petersen, L N

    1997-01-01

    Cholera toxin (CTX) and pertussis toxin (PTX) were examined for their ability to inhibit glucose transport in perfused skeletal muscle. Twenty-five hours after an intravenous injection of CTX, basal transport was decreased approximately 30%, and insulin- and contraction-stimulated transport...

  19. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport

    OpenAIRE

    Naftalin, Richard J; Cunningham, Philip; Afzal-Ahmed, Iram

    2004-01-01

    Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide...

  20. Regulation of myocardial glucose transporters GLUT1 and GLUT4 in chronically anemic fetal lambs.

    Science.gov (United States)

    Ralphe, J Carter; Nau, Peter N; Mascio, Christopher E; Segar, Jeffrey L; Scholz, Thomas D

    2005-10-01

    Little is known about the chronic adaptations that take place in the fetal heart to allow for increased substrate delivery in response to chronic stress. Because glucose is an important fuel for the fetal cardiomyocytes, we hypothesized that myocardial glucose transporters 1 and 4 (GLUT1 and GLUT4, respectively) are up-regulated in the fetal sheep heart that is chronically stressed by anemia. Fetal sheep at 128 d gestation underwent daily isovolumic hemorrhage and determination of myocardial blood flow, oxygen consumption, and substrate utilization. At the end of 3 or 7 d of anemia, myocardial levels of GLUT1 and GLUT4 mRNA and protein were measured and subcellular localization was determined. Despite stable heart rate and blood pressure, anemia caused a nearly 4-fold increase in right and left ventricular (RV and LV) free wall blood flow. No significant change in myocardial glucose uptake was found and serum insulin levels remained stable. Both 3-d RV and LV and 7-d RV mRNA and protein levels of GLUT1 and GLUT4 were unchanged; 7-d LV GLUT1 and GLUT4 mRNA levels were also stable. However, LV GLUT1 protein levels declined significantly, whereas LV GLUT4 protein levels were increased. In the steady state, GLUT4 protein localized to the sarcolemma membrane. These findings suggest that the glucose transporters are post-transcriptionally regulated in myocardium of chronically anemic fetal sheep with changes that mimic normal postnatal development. Unlike the postnatal heart, localization of GLUT4 to the cell membrane suggests the importance of GLUT4 in basal glucose uptake in the stressed fetal heart.

  1. [Transmembrane transport behavior of in vitro HepG2 cells of ananas and its effect on lipids and glucose distribution].

    Science.gov (United States)

    Pang, Yu-Nong; Chai, Yu-Shuang; Jiang, Jing-Fei; Wang, Xin-Pei; Yu, Xuan; Lei, Fan; Xing, Dong-Ming; Du, Li-Jun

    2014-08-01

    Pineapple (Ananas comosus) leaves contain mainly phenolic components with antioxidant and hypolipidemic effects. One of the principle components is p-coumaric acid. In this study, the transport behavior of p-coumaric acid, was observed after the administration of pineapple leaf phenols in vitro. Simultaneously, the effect of the phenols on glucose, total cholesterol and triglycerides transportation and metabolism in HepG2 cells was also observed. The results showed that the phenols had good transport characteristics. 5 min after the administration, p-coumaric acid of the phenols could be detected, and the content of p-coumaric acid reached the peak concentration after 60 min of the administration. p-coumaric acid of phenols have time-and dose-dependent manner. While promoting glucose transporter (GLUT4) and low density lipoprotein receptor (LDLR) expression, the phenols decreased intracellular lipid content. This reduction of intracellular lipid content was highly correlated with the promotion of lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) expression, while the reduction of intracellular glucose levels was correlated with glycogen synthesis in the cells.

  2. Steady-state brain glucose transport kinetics re-evaluated with a four-state conformational model

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    João M N Duarte

    2009-10-01

    Full Text Available Glucose supply from blood to brain occurs through facilitative transporter proteins. A near linear relation between brain and plasma glucose has been experimentally determined and described by a reversible model of enzyme kinetics. A conformational four-state exchange model accounting for trans-acceleration and asymmetry of the carrier was included in a recently developed multi-compartmental model of glucose transport. Based on this model, we demonstrate that brain glucose (Gbrain as function of plasma glucose (Gplasma can be described by a single analytical equation namely comprising three kinetic compartments: blood, endothelial cells and brain. Transport was described by four parameters: apparent half saturation constant Kt, apparent maximum rate constant Tmax, glucose consumption rate CMRglc, and the iso-inhibition constant Kii that suggests Gbrain as inhibitor of the isomerisation of the unloaded carrier. Previous published data, where Gbrain was quantified as a function of plasma glucose by either biochemical methods or NMR spectroscopy, were used to determine the aforementioned kinetic parameters. Glucose transport was characterized by Kt ranging from 1.5 to 3.5 mM, Tmax/CMRglc from 4.6 to 5.6, and Kii from 51 to 149 mM. It was noteworthy that Kt was on the order of a few mM, as previously determined from the reversible model. The conformational four-state exchange model of glucose transport into the brain includes both efflux and transport inhibition by Gbrain, predicting that Gbrain eventually approaches a maximum concentration. However, since Kii largely exceeds Gplasma, iso-inhibition is unlikely to be of substantial importance for plasma glucose below 25 mM. As a consequence, the reversible model can account for most experimental observations under euglycaemia and moderate cases of hypo- and hyperglycaemia.

  3. Adolescents with clinical type 1 diabetes display reduced red blood cell glucose transporter isoform 1 (GLUT1).

    Science.gov (United States)

    Garg, Meena; Thamotharan, Manikkavasagar; Becker, Dorothy J; Devaskar, Sherin U

    2014-11-01

    Type 1 diabetic (T1D) adolescent children on insulin therapy suffer episodes of both hyper- and hypoglycemic episodes. Glucose transporter isoform GLUT1 expressed in blood-brain barrier (BBB) and red blood cells (RBC) compensates for perturbed circulating glucose toward protecting the supply to brain and RBCs. We hypothesized that RBC-GLUT1 concentration, as a surrogate for BBB-GLUT1, is altered in T1D children. To test this hypothesis, we measured RBC-GLUT1 by enzyme-linked immunosorbent assay (ELISA) in T1D children (n = 72; mean age 15.3 ± 0.2 yr) and control children (CON; n = 11; mean age 15.6 ± 0.9 yr) after 12 h of euglycemia and during a hyperinsulinemic-hypoglycemic clamp with a nadir blood glucose of ~3.3 mmol/L for 90 min (clamp I) or ~3 mmol/L for 45 min (clamp II). Reduced baseline RBC-GLUT1 was observed in T1D (2.4 ± 0.17 ng/ng membrane protein); vs. CON (4.2 ± 0.61 ng/ng protein) (p < 0.0001). Additionally, baseline RBC-GLUT1 in T1D negatively correlated with hemoglobin A1c (HbA1c) (R = -0.23, p < 0.05) but not in CON (R = 0.06, p < 0.9). Acute decline in serum glucose to 3.3 mmol/L (90 min) or 3 mmol/L (45 min) did not change baseline RBC-GLUT1 in T1D or CON children. We conclude that reduced RBC-GLUT1 encountered in T1D, with no ability to compensate by increasing during acute hypoglycemia over the durations examined, may demonstrate a vulnerability of impaired RBC glucose transport (serving as a surrogate for BBB), especially in those with the worst control. We speculate that this may contribute to the perturbed cognition seen in T1D adolescents. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  4. Glucose ingestion during endurance training in men attenuates expression of myokine receptor

    DEFF Research Database (Denmark)

    Åkerström, Thorbjörn; Krogh-Madsen, Rikke; Petersen, Anne Marie Winther

    2009-01-01

    -leg) while ingesting a glucose solution (Glc) and ingested a placebo (Plc) while training the other leg (Plc-leg). Endurance training increased peak power by 14% and reduced the exercise-induced gene expression of IL-6 and IL-6Ralpha in skeletal muscle and IL-6 plasma concentration. The IL-6Ralpha density...

  5. How is glucose transported through cell membrane? ¿Cómo se transporta la glucosa a través de la membrana celular?

    OpenAIRE

    Luis Carlos Burgos Herrera; Diana Patricia Díaz Hernández

    2002-01-01

    Glucose is the main energy supply for the cell and requires a transport protein to enter through cell membranes. Two monosacharid transport systems have been described: SGLT (sodium-glucose transporters) and GLUT (glucose transporters). In this article we review the main molecular, biochemical and functional characteristics of these monosacharid transporters. La glucosa es el principal sustrato energético de la célula y para su ingreso requiere una proteína transportadora en la membrana celul...

  6. Immunocytochemical analysis of glucose transporter protein-1 (GLUT-1) in typical, brain invasive, atypical and anaplastic meningioma.

    Science.gov (United States)

    van de Nes, Johannes A P; Griewank, Klaus G; Schmid, Kurt-Werner; Grabellus, Florian

    2015-02-01

    Glucose transporter-1 (GLUT-1) is one of the major isoforms of the family of glucose transporter proteins that facilitates the import of glucose in human cells to fuel anaerobic metabolism. The present study was meant to determine the extent of the anaerobic/hypoxic state of the intratumoral microenvironment by staining for GLUT-1 in intracranial non-embolized typical (WHO grade I; n = 40), brain invasive and atypical (each WHO grade II; n = 38) and anaplastic meningiomas (WHO grade III, n = 6). In addition, GLUT-1 staining levels were compared with the various histological criteria used for diagnosing WHO grade II and III meningiomas, namely, brain invasion, increased mitotic activity and atypical cytoarchitectural change, defined by the presence of at least three out of hypercellularity, sheet-like growth, prominent nucleoli, small cell change and "spontaneous" necrosis. The level of tumor hypoxia was assessed by converting the extent and intensity of the stainings by multiplication in an immunoreactive score (IRS) and statistically evaluated. The results were as follows. (1) While GLUT-1 expression was found to be mainly weak in WHO grade I meningiomas (IRS = 1-4) and to be consistently strong in WHO grade III meningiomas (IRS = 6-12), in WHO grade II meningiomas GLUT-1 expression was variable (IRS = 1-9). (2) Histologically typical, but brain invasive meningiomas (WHO grade II) showed no or similarly low levels of GLUT-1 expression as observed in WHO grade I meningiomas (IRS = 0-4). (3) GLUT-1 expression was observed in the form of a patchy, multifocal staining reaction in 76% of stained WHO grade I-III meningiomas, while diffuse staining (in 11%) and combined multifocal and areas of diffuse staining (in 13%) were only detected in WHO grades II and III meningiomas, except for uniform staining in angiomatous WHO grade I meningioma. (4) "Spontaneous" necrosis and small cell change typically occurred away from the intratumoral capillary

  7. Glycolysis Controls Plasma Membrane Glucose Sensors To Promote Glucose Signaling in Yeasts

    Science.gov (United States)

    Cairey-Remonnay, Amélie; Deffaud, Julien; Wésolowski-Louvel, Micheline; Lemaire, Marc

    2014-01-01

    Sensing of extracellular glucose is necessary for cells to adapt to glucose variation in their environment. In the respiratory yeast Kluyveromyces lactis, extracellular glucose controls the expression of major glucose permease gene RAG1 through a cascade similar to the Saccharomyces cerevisiae Snf3/Rgt2/Rgt1 glucose signaling pathway. This regulation depends also on intracellular glucose metabolism since we previously showed that glucose induction of the RAG1 gene is abolished in glycolytic mutants. Here we show that glycolysis regulates RAG1 expression through the K. lactis Rgt1 (KlRgt1) glucose signaling pathway by targeting the localization and probably the stability of Rag4, the single Snf3/Rgt2-type glucose sensor of K. lactis. Additionally, the control exerted by glycolysis on glucose signaling seems to be conserved in S. cerevisiae. This retrocontrol might prevent yeasts from unnecessary glucose transport and intracellular glucose accumulation. PMID:25512610

  8. Rewiring the Glucose Transportation and Central Metabolic Pathways for Overproduction of N-Acetylglucosamine in Bacillus subtilis.

    Science.gov (United States)

    Gu, Yang; Deng, Jieying; Liu, Yanfeng; Li, Jianghua; Shin, Hyun-Dong; Du, Guocheng; Chen, Jian; Liu, Long

    2017-10-01

    N-acetylglucosamine (GlcNAc) is an important amino sugar extensively used in the healthcare field. In a previous study, the recombinant Bacillus subtilis strain BSGN6-P xylA -glmS-pP43NMK-GNA1 (BN0-GNA1) had been constructed for microbial production of GlcNAc by pathway design and modular optimization. Here, the production of GlcNAc is further improved by rewiring both the glucose transportation and central metabolic pathways. First, the phosphotransferase system (PTS) is blocked by deletion of three genes, yyzE (encoding the PTS system transporter subunit IIA YyzE), ypqE (encoding the PTS system transporter subunit IIA YpqE), and ptsG (encoding the PTS system glucose-specific EIICBA component), resulting in 47.6% increase in the GlcNAc titer (from 6.5 ± 0.25 to 9.6 ± 0.16 g L -1 ) in shake flasks. Then, reinforcement of the expression of the glcP and glcK genes and optimization of glucose facilitator proteins are performed to promote glucose import and phosphorylation. Next, the competitive pathways for GlcNAc synthesis, namely glycolysis, peptidoglycan synthesis pathway, pentose phosphate pathway, and tricarboxylic acid cycle, are repressed by initiation codon-optimization strategies, and the GlcNAc titer in shake flasks is improved from 10.8 ± 0.25 to 13.2 ± 0.31 g L -1 . Finally, the GlcNAc titer is further increased to 42.1 ± 1.1 g L -1 in a 3-L fed-batch bioreactor, which is 1.72-fold that of the original strain, BN0-GNA1. This study shows considerably enhanced GlcNAc production, and the metabolic engineering strategy described here will be useful for engineering other prokaryotic microorganisms for the production of GlcNAc and related molecules. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Proanthocyanidins Prevent High Glucose-Induced Eye Malformation by Restoring Pax6 Expression in Chick Embryo

    Directory of Open Access Journals (Sweden)

    Rui-Rong Tan

    2015-08-01

    Full Text Available Gestational diabetes mellitus (GDM is one of the leading causes of offspring malformations, in which eye malformation is an important disease. It has raised demand for therapy to improve fetal outcomes. In this study, we used chick embryo to establish a GDM model to study the protective effects of proanthocyanidins on eye development. Chick embryos were exposed to high glucose (0.2 mmol/egg on embryo development day (EDD 1. Proanthocyanidins (1 and 10 nmol/egg were injected into the air sac on EDD 0. Results showed that both dosages of proanthocyanidins could prevent the eye malformation and rescue the high glucose-induced oxidative stress significantly, which the similar effects were showed in edaravone. However, proanthocyanidins could not decrease the glucose concentration of embryo eye. Moreover, the key genes regulating eye development, Pax6, was down-regulated by high glucose. Proanthocyanidins could restore the suppressed expression of Pax6. These results indicated proanthocyanidins might be a promising natural agent to prevent high glucose-induced eye malformation by restoring Pax6 expression.

  10. Glucose availability is a decisive factor for Nrf2-mediated gene expression

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    Elke H. Heiss

    2013-01-01

    Full Text Available Activation of the transcription factor Nrf2 (nuclear factor-erythroid 2-related factor 2 is one of the major cellular defense lines against oxidative and xenobiotic stress, but also influences genes involved in lipid and glucose metabolism. It is unresolved whether the cytoprotective and metabolic responses mediated by Nrf2 are connected or separable events in non-malignant cells. In this study we show that activation of Nrf2, either by the small molecule sulforaphane or knockout of the Nrf2 inhibitor Keap1, leads to increased cellular glucose uptake and increased glucose addiction in fibroblasts. Upon Nrf2 activation glucose is preferentially metabolized through the pentose phosphate pathway with increased production of NADPH. Interference with the supply of glucose or the pentose phosphate pathway and NADPH generation not only hampers Nrf2-mediated detoxification of reactive oxygen species on the enzyme level but also Nrf2-initiated expression of antioxidant defense proteins, such as glutathione reductase and heme-oxygenase1. We conclude that the Nrf2-dependent protection against oxidative stress relies on an intact pentose phosphate pathway and that there is crosstalk between metabolism and detoxification already at the level of gene expression in mammalian cells.

  11. Erythritol reduces small intestinal glucose absorption, increases muscle glucose uptake, improves glucose metabolic enzymes activities and increases expression of Glut-4 and IRS-1 in type 2 diabetic rats.

    Science.gov (United States)

    Chukwuma, Chika Ifeanyi; Mopuri, Ramgopal; Nagiah, Savania; Chuturgoon, Anil Amichund; Islam, Md Shahidul

    2017-08-02

    Studies have reported that erythritol, a low or non-glycemic sugar alcohol possesses anti-hyperglycemic and anti-diabetic potentials but the underlying mode of actions is not clear. This study investigated the underlying mode of actions behind the anti-hyperglycemic and anti-diabetic potentials of erythritol using different experimental models (experiment 1, 2 and 3). Experiment 1 examined the effects of increasing concentrations (2.5-20%) of erythritol on glucose absorption and uptake in isolated rat jejunum and psoas muscle, respectively. Experiments 2 and 3 examined the effects of a single oral dose of erythritol (1 g/kg bw) on intestinal glucose absorption, gastric emptying and postprandial blood glucose increase, glucose tolerance, serum insulin level, muscle/liver hexokinase and liver glucose-6 phosphatase activities, liver and muscle glycogen contents and mRNA and protein expression of muscle Glut-4 and IRS-1 in normal and type 2 diabetic animals. Experiment 1 revealed that erythritol dose dependently enhanced muscle glucose ex vivo. Experiment 2 demonstrated that erythritol feeding delayed gastric emptying and reduced small intestinal glucose absorption as well as postprandial blood glucose rise, especially in diabetic animals. Experiment 3 showed that erythritol feeding improved glucose tolerance, muscle/liver hexokinase and liver glucose-6 phosphatase activities, glycogen storage and also modulated expression of muscle Glut-4 and IRS-1 in diabetic animals. Data suggest that erythritol may exert anti-hyperglycemic effects not only via reducing small intestinal glucose absorption, but also by increasing muscle glucose uptake, improving glucose metabolic enzymes activity and modulating muscle Glut-4 and IRS-1 mRNA and protein expression. Hence, erythritol may be a useful dietary supplement for managing hyperglycemia, particularly for T2D.

  12. PTEN Regulates Glucose Transporter Recycling by Impairing SNX27 Retromer Assembly.

    Science.gov (United States)

    Shinde, Swapnil Rohidas; Maddika, Subbareddy

    2017-11-07

    The tumor suppressor PTEN executes cellular functions predominantly through its phosphatase activity. Here we identified a phosphatase-independent role for PTEN during vesicular trafficking of the glucose transporter GLUT1. PTEN physically interacts with SNX27, a component of the retromer complex that recycles transmembrane receptors such as GLUT1 from endosomes to the plasma membrane. PTEN binding with SNX27 prevents GLUT1 accumulation at the plasma membrane because of defective recycling and thus reduces cellular glucose uptake. Mechanistically, PTEN blocks the association of SNX27 with VPS26 and thereby hinders assembly of a functional retromer complex during the receptor recycling process. Importantly, we found a PTEN somatic mutation (T401I) that is defective in disrupting the association between SNX27 and VPS26, suggesting a critical role for PTEN in controlling optimal GLUT1 levels at the membrane to prevent tumor progression. Together, our results reveal a fundamental role of PTEN in the regulation of the SNX27 retromer pathway, which governs glucose transport and might contribute to PTEN tumor suppressor function. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  13. PTEN expression and its association with glucose control and calorie supplementation in critically ill patients.

    Science.gov (United States)

    Molfino, Alessio; Alessandri, Francesco; Mosillo, Paola; Dell'Utri, Donatella; Farcomeni, Alessio; Amabile, Maria Ida; Laviano, Alessandro

    2017-11-04

    Phosphatase and tensin homologue (PTEN) reduces insulin sensitivity. Since critically ill patients present insulin resistance, we aimed at assessing the role of PTEN expression on glucose homeostasis and clinical outcome in patients admitted to an intensive care unit (ICU) and receiving artificial nutrition. Observational, single-center study conducted in one ICU in Rome, Italy on adult patients hospitalized for trauma. Plasma glucose levels and its variability were recorded in patients receiving artificial nutrition. PTEN expression was measured by western blotting analysis and the associations between PTEN, plasma glucose levels and variability, and calories administered were investigated. Parametric and non-parametric tests were used, as appropriate. Twenty consecutive patients (13 men and 7 women, mean age of 37.3 ± 12.7 years) were studied. No correlation between plasma glucose and PTEN was documented (r = -0.15, P = 0.55), neither between glycemic variability and PTEN expression (r = -0.00, P = 0.99). However, total kcal/day administered and PTEN expression significantly correlated (r = 0.56, P = 0.01). Also, patients with PTEN levels below the median received less kcal/day than those with PTEN above the median (P = 0.048). This association was more pronounced when normalized per body weight (P = 0.03) and after adjusting for the average of insulin daily administered (P = 0.02). PTEN expression might significantly contribute to glucose homeostasis and disposal in critically ill patients receiving artificial nutrition. Larger samples are necessary to confirm our observation. NCT01796847 (www.clinicaltrials.gov) submitted on February 11, 2013. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  14. Genetic variation of the GLUT10 glucose transporter (SLC2A10) and relationships to type 2 diabetes and intermediary traits

    DEFF Research Database (Denmark)

    Andersen, Gitte; Rose, Christian Schack; Hamid, Yasmin Hassan

    2003-01-01

    The SLC2A10 gene encodes the GLUT10 facilitative glucose transporter, which is expressed in high amounts in liver and pancreas. The gene is mapped to chromosome 20q12-q13.1, a region that has been shown to be linked to type 2 diabetes. The gene was examined in 61 Danish type 2 diabetic patients......, and a total of six variants (-27C-->T, Ala206Thr, Ala272Ala, IVS2 + 10G-->A, IVS4 + 18T-->G, and IVS4 + 26G-->A) were identified and investigated in an association study, which included 503 type 2 diabetic patients and 510 glucose-tolerant control subjects. None of the variants were associated with type 2...... substantially to the pathogenesis of type 2 diabetes in the examined study population. However, the codon 206 polymorphism may be related to the interindividual variation in fasting and oral glucose-induced serum insulin levels....

  15. Analysis of Metabolism of 6FDG: A PET Glucose Transport Tracer

    Science.gov (United States)

    Muzic, Raymond F.; Chandramouli, Visvanathan; Huang, Hsuan-Ming; Wu, Chunying; Wang, Yanming; Ismail-Beigi, Faramarz

    2011-01-01

    Introduction We are developing 18F-labeled 6-fluoro-6-deoxy-D-glucose ([18F]6FDG) as a tracer of glucose transport. As part of this process it is important to characterize and quantify putative metabolites. In contrast to the ubiquitous PET tracer 18F-labeled 2-fluoro-2-deoxy-D-glucose ([18F]2FDG) which is phosphorylated and trapped intracellularly, the substitution of fluorine for a hydroxyl group at carbon 6 in [18F]6FDG should prevent its phosphorylation. Consequently, [18F]6FDG has the potential to trace the transport step of glucose metabolism without the confounding effects of phosphorylation and subsequent steps of metabolism. Herein the focus is to determine whether, and the degree to which, [18F]6FDG remains unchanged following intravenous injection. Methods Biodistribution studies were performed using 6FDG labeled with 18F as well as the longer-lived radionuclides 3H and 14C. Tissues were harvested at 1, 6, and 24 h following intravenous administration and radioactivity was extracted from the tissues and analyzed using a combination of ion exchange columns, high-performance liquid chromatography, and chemical reactivity. Results At the 1 h time-point, the vast majority of radioactivity in the liver, brain, heart, skeletal muscle, and blood was identified as 6FDG. At the 6- and 24-h time-points there was evidence of a minor amount of radioactive materials that appeared to be 6-fluoro-6-deoxy-D-sorbitol and possibly 6-fluoro-6-deoxy-D-gluconic acid. Conclusion On the time scale typical of PET imaging studies radioactive metabolites of [18F]6FDG are negligible. PMID:21718942

  16. Analysis of metabolism of 6FDG: a PET glucose transport tracer

    Energy Technology Data Exchange (ETDEWEB)

    Muzic, Raymond F., E-mail: raymond.muzic@case.edu [Department of Radiology, Case Western Reserve University, Cleveland, OH 44106 (United States); Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States); Chandramouli, Visvanathan [Department of Radiology, Case Western Reserve University, Cleveland, OH 44106 (United States); Huang, Hsuan-Ming [Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States); Wu Chunying; Wang Yanming [Department of Radiology, Case Western Reserve University, Cleveland, OH 44106 (United States); Ismail-Beigi, Faramarz [Department of Medicine, Case Western Reserve University, Cleveland, OH 44106 (United States)

    2011-07-15

    Introduction: We are developing {sup 18}F-labeled 6-fluoro-6-deoxy-D-glucose ([{sup 18}F]6FDG) as a tracer of glucose transport. As part of this process it is important to characterize and quantify putative metabolites. In contrast to the ubiquitous positron emission tomography (PET) tracer {sup 18}F-labeled 2-fluoro-2-deoxy-D-glucose ([{sup 18}F]2FDG) which is phosphorylated and trapped intracellularly, the substitution of fluorine for a hydroxyl group at carbon-6 in [{sup 18}F]6FDG should prevent its phosphorylation. Consequently, [{sup 18}F]6FDG has the potential to trace the transport step of glucose metabolism without the confounding effects of phosphorylation and subsequent steps of metabolism. Herein the focus is to determine whether, and the degree to which, [{sup 18}F]6FDG remains unchanged following intravenous injection. Methods: Biodistribution studies were performed using 6FDG labeled with {sup 18}F or with the longer-lived radionuclides {sup 3}H and {sup 14}C. Tissues were harvested at 1, 6, and 24 h following intravenous administration and radioactivity was extracted from the tissues and analyzed using a combination of ion exchange columns, high-performance liquid chromatography, and chemical reactivity. Results: At the 1 h time-point, the vast majority of radioactivity in the liver, brain, heart, skeletal muscle, and blood was identified as 6FDG. At the 6-h and 24-h time points, there was evidence of a minor amount of radioactive material that appeared to be 6-fluoro-6-deoxy-D-sorbitol and possibly 6-fluoro-6-deoxy-D-gluconic acid. Conclusion: On the time scale typical of PET imaging studies radioactive metabolites of [{sup 18}F]6FDG are negligible.

  17. PTEN dephosphorylates AKT to prevent the expression of GLUT1 on plasmamembrane and to limit glucose consumption in cancer cells

    Science.gov (United States)

    Ferraresi, Alessandra; Morani, Federica; Follo, Carlo; Isidoro, Ciro

    2016-01-01

    GLUT1 is the facilitative transporter playing the major role in the internalization of glucose. Basally, GLUT1 resides on vesicles located in a para-golgian area, and is translocated onto the plasmamembrane upon activation of the PI3KC1-AKT pathway. In proliferating cancer cells, which demand a high quantity of glucose for their metabolism, GLUT1 is permanently expressed on the plasmamembrane. This is associated with the abnormal activation of the PI3KC1-AKT pathway, consequent to the mutational activation of PI3KC1 and/or the loss of PTEN. The latter, in fact, could antagonize the phosphorylation of AKT by limiting the availability of Phosphatidylinositol (3,4,5)-trisphosphate. Here, we asked whether PTEN could control the plasmamembrane expression of GLUT1 also through its protein-phosphatase activity on AKT. Experiments of co-immunoprecipitation and in vitro de-phosphorylation assay with homogenates of cells transgenically expressing the wild type or knocked-down mutants (lipid-phosphatase, protein-phosphatase, or both) isoforms demonstrated that indeed PTEN physically interacts with AKT and drives its dephosphorylation, and so limiting the expression of GLUT1 at the plasmamembrane. We also show that growth factors limit the ability of PTEN to dephosphorylate AKT. Our data emphasize the fact that PTEN acts in two distinct steps of the PI3k/AKT pathway to control the expression of GLUT1 at the plasmamembrane and, further, add AKT to the list of the protein substrates of PTEN. PMID:27829222

  18. Sweet taste receptor expression in ruminant intestine and its activation by artificial sweeteners to regulate glucose absorption.

    Science.gov (United States)

    Moran, A W; Al-Rammahi, M; Zhang, C; Bravo, D; Calsamiglia, S; Shirazi-Beechey, S P

    2014-01-01

    Absorption of glucose from the lumen of the intestine into enterocytes is accomplished by sodium-glucose co-transporter 1 (SGLT1). In the majority of mammalian species, expression (this includes activity) of SGLT1 is upregulated in response to increased dietary monosaccharides. This regulatory pathway is initiated by sensing of luminal sugar by the gut-expressed sweet taste receptor. The objectives of our studies were to determine (1) if the ruminant intestine expresses the sweet taste receptor, which consists of two subunits [taste 1 receptor 2 (T1R2) and 3 (T1R3)], and other key signaling molecules required for SGLT1 upregulation in nonruminant intestines, and (2) whether T1R2-T1R3 sensing of artificial sweeteners induces release of glucagon-like peptide-2 (GLP-2) and enhances SGLT1 expression. We found that the small intestine of sheep and cattle express T1R2, T1R3, G-protein gustducin, and GLP-2 in enteroendocrine L-cells. Maintaining 110-d-old ruminating calves for 60d on a diet containing a starter concentrate and the artificial sweetener Sucram (consisting of saccharin and neohesperidin dihydrochalcone; Pancosma SA, Geneva, Switzerland) enhances (1) Na(+)-dependent d-glucose uptake by over 3-fold, (2) villus height and crypt depth by 1.4- and 1.2-fold, and (3) maltase- and alkaline phosphatase-specific activity by 1.5-fold compared to calves maintained on the same diet without Sucram. No statistically significant differences were observed for rates of intestinal glucose uptake, villus height, crypt depth, or enzyme activities between 50-d-old milk-fed calves and calves maintained on the same diet containing Sucram. When adult cows were kept on a diet containing 80:20 ryegrass hay-to-concentrate supplemented with Sucram, more than a 7-fold increase in SGLT1 protein abundance was noted. Collectively, the data indicate that inclusion of this artificial sweetener enhances SGLT1 expression and mucosal growth in ruminant animals. Exposure of ruminant sheep

  19. Partial sequencing and expression of genes involved in glucose metabolism in adipose tissues and skeletal muscle of healthy cats.

    Science.gov (United States)

    Zini, Eric; Linscheid, Philippe; Franchini, Marco; Kaufmann, Karin; Monnais, Edouard; Kutter, Annette P; Ackermann, Mathias; Lutz, Thomas A; Reusch, Claudia E

    2009-04-01

    Impaired insulin sensitivity is increasingly recognised in cats, but sequences of genes involved in insulin-signalling are largely undetermined in this species. In this study, extended feline mRNA sequences were determined for the adiponectin, glucose transporter-1 (GLUT1), GLUT4, peroxisome proliferative activated receptor-gamma1 (PPARgamma1), PPARgamma2, plasminogen activator inhibitor-1 (PAI-1), monocyte chemoattractant protein-1 (MCP-1) and insulin receptor genes. Conserved dog-specific primers identified from human-dog mRNA alignments were used to amplify feline cDNA in the polymerase chain reaction (PCR). The feline sequences determined by this method were used to design feline-specific primers suitable for real-time PCR for quantification of gene expression in insulin sensitive tissues of healthy cats. Partial sequences of feline mRNAs had 86-95% identity with dog and human genes. Expression of adiponectin, GLUT1, GLUT4, PPARgamma1, PPARgamma2, PAI-1 and insulin receptor mRNA was detected and quantified in subcutaneous and visceral fat and skeletal muscle, whereas MCP-1 mRNA was detected in adipose tissue but not in skeletal muscle. Further characterisation of genes related to glucose metabolism in cats will provide additional insights into insulin-signalling mechanisms in this species.

  20. Diagnosing Glucose Transporter 1 Deficiency at Initial Presentation Facilitates Early Treatment.

    Science.gov (United States)

    Akman, Cigdem Inan; Yu, Julia; Alter, Aliza; Engelstad, Kristin; De Vivo, Darryl C

    2016-04-01

    To profile the initial clinical events of glucose transporter 1 deficiency syndrome (Glut1 DS) in order to facilitate the earliest possible diagnosis. We retrospectively reviewed 133 patients with Glut1 DS from a single institution. Family interviews and medical record reviews identified the first clinical event(s) reported by the caregivers. Average age of the first event was 8.15 ± 11.9 months (range: 0.01-81). Ninety-one patients experienced the first symptom before age 6 months (68%). Thirty-three additional patients (25%) presented before age 2 years. Only 9 patients (7%), reported the first event after age 2 years. Seizures were the most common first event (n = 81, 61%), followed by eye movement abnormalities (n = 51, 38%) and changes in muscle strength and tone (n = 30, 22%). Eye movement abnormalities, lower cerebrospinal fluid glucose values, and lower Columbia Neurological Scores correlated with earlier onset of the first event (r: -0.17, 0.22, and 0.25 respectively, P < .05). There was no correlation with age of first event and red blood cell glucose uptake or mutation type. Glut1 DS is a treatable cause of infantile onset encephalopathy. Health care providers should recognize the wide spectrum of paroxysmal events that herald the clinical onset of Glut1 DS in early infancy to facilitate prompt diagnosis, immediate treatment, and improved long-term outcome. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Assessment of glucose homeostasis in crossbred steer progeny sired by Brahman bulls that experienced prenatal transportation stress

    Science.gov (United States)

    The objective of this experiment was to assess glucose homeostasis of crossbred male progeny whose Brahman sires experienced prenatal transportation stress (PS) in utero. Sixteen steers (PNS group) sired by 3 PS bulls gestating dams were transported for 2 h at 60, 80, 100, 120, and 140 ± 5 d of gest...

  2. Glucose Modulation Induces Lysosome Formation and Increases Lysosomotropic Drug Sequestration via the P-Glycoprotein Drug Transporter.

    Science.gov (United States)

    Seebacher, Nicole A; Lane, Darius J R; Jansson, Patric J; Richardson, Des R

    2016-02-19

    Pgp is functional on the plasma membrane and lysosomal membrane. Lysosomal-Pgp can pump substrates into the organelle, thereby trapping certain chemotherapeutics (e.g. doxorubicin; DOX). This mechanism serves as a "safe house" to protect cells against cytotoxic drugs. Interestingly, in contrast to DOX, lysosomal sequestration of the novel anti-tumor agent and P-glycoprotein (Pgp) substrate, di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT), induces lysosomal membrane permeabilization. This mechanism of lysosomal-Pgp utilization enhances cytotoxicity to multidrug-resistant cells. Consequently, Dp44mT has greater anti-tumor activity in drug-resistant relative to non-Pgp-expressing tumors. Interestingly, stressors in the tumor microenvironment trigger endocytosis for cell signaling to assist cell survival. Hence, this investigation examined how glucose variation-induced stress regulated early endosome and lysosome formation via endocytosis of the plasma membrane. Furthermore, the impact of glucose variation-induced stress on resistance to DOX was compared with Dp44mT and its structurally related analogue, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC). These studies showed that glucose variation-induced stress-stimulated formation of early endosomes and lysosomes. In fact, through the process of fluid-phase endocytosis, Pgp was redistributed from the plasma membrane to the lysosomal membrane via early endosome formation. This lysosomal-Pgp actively transported the Pgp substrate, DOX, into the lysosome where it became trapped as a result of protonation at pH 5. Due to increased lysosomal DOX trapping, Pgp-expressing cells became more resistant to DOX. In contrast, cytotoxicity of Dp44mT and DpC was potentiated due to more lysosomes containing functional Pgp under glucose-induced stress. These thiosemicarbazones increased lysosomal membrane permeabilization and cell death. This mechanism has critical implications for drug-targeting in

  3. Glucose Modulation Induces Lysosome Formation and Increases Lysosomotropic Drug Sequestration via the P-Glycoprotein Drug Transporter*

    Science.gov (United States)

    Seebacher, Nicole A.; Lane, Darius J. R.; Jansson, Patric J.; Richardson, Des R.

    2016-01-01

    Pgp is functional on the plasma membrane and lysosomal membrane. Lysosomal-Pgp can pump substrates into the organelle, thereby trapping certain chemotherapeutics (e.g. doxorubicin; DOX). This mechanism serves as a “safe house” to protect cells against cytotoxic drugs. Interestingly, in contrast to DOX, lysosomal sequestration of the novel anti-tumor agent and P-glycoprotein (Pgp) substrate, di-2-pyridylketone-4,4-dimethyl-3-thiosemicarbazone (Dp44mT), induces lysosomal membrane permeabilization. This mechanism of lysosomal-Pgp utilization enhances cytotoxicity to multidrug-resistant cells. Consequently, Dp44mT has greater anti-tumor activity in drug-resistant relative to non-Pgp-expressing tumors. Interestingly, stressors in the tumor microenvironment trigger endocytosis for cell signaling to assist cell survival. Hence, this investigation examined how glucose variation-induced stress regulated early endosome and lysosome formation via endocytosis of the plasma membrane. Furthermore, the impact of glucose variation-induced stress on resistance to DOX was compared with Dp44mT and its structurally related analogue, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC). These studies showed that glucose variation-induced stress-stimulated formation of early endosomes and lysosomes. In fact, through the process of fluid-phase endocytosis, Pgp was redistributed from the plasma membrane to the lysosomal membrane via early endosome formation. This lysosomal-Pgp actively transported the Pgp substrate, DOX, into the lysosome where it became trapped as a result of protonation at pH 5. Due to increased lysosomal DOX trapping, Pgp-expressing cells became more resistant to DOX. In contrast, cytotoxicity of Dp44mT and DpC was potentiated due to more lysosomes containing functional Pgp under glucose-induced stress. These thiosemicarbazones increased lysosomal membrane permeabilization and cell death. This mechanism has critical implications for drug-targeting in

  4. Effect of in vivo injection of cholera and pertussis toxin on glucose transport in rat skeletal muscle

    DEFF Research Database (Denmark)

    Ploug, Thorkil; Han, X; Petersen, L N

    1997-01-01

    in GLUT-1 protein content was found. In contrast, GLUT-4 mRNA was unchanged, but transcripts for GLUT-1 were increased > or = 150% in all three muscles from CTX-treated rats. The findings suggest that CTX via increased cAMP impairs basal as well as insulin- and contraction-stimulated muscle glucose......Cholera toxin (CTX) and pertussis toxin (PTX) were examined for their ability to inhibit glucose transport in perfused skeletal muscle. Twenty-five hours after an intravenous injection of CTX, basal transport was decreased approximately 30%, and insulin- and contraction-stimulated transport...

  5. Stimulation of Na{sup +}/K{sup +} ATPase activity and Na{sup +} coupled glucose transport by {beta}-catenin

    Energy Technology Data Exchange (ETDEWEB)

    Sopjani, Mentor [Department of Physiology, University of Tuebingen (Germany); Department of Chemistry, University of Prishtina, Kosovo (Country Unknown); Alesutan, Ioana; Wilmes, Jan [Department of Physiology, University of Tuebingen (Germany); Dermaku-Sopjani, Miribane [Department of Physiology, University of Tuebingen (Germany); Faculty of Medicine, University of Prishtina, Kosovo (Country Unknown); Lam, Rebecca S. [Department of Physiology, University of Tuebingen (Germany); Department of Molecular Neurogenetics, Max Planck Institute of Biophysics, Frankfurt/Main (Germany); Koutsouki, Evgenia [Department of Physiology, University of Tuebingen (Germany); Jakupi, Muharrem [Faculty of Medicine, University of Prishtina, Kosovo (Country Unknown); Foeller, Michael [Department of Physiology, University of Tuebingen (Germany); Lang, Florian, E-mail: florian.lang@uni-tuebingen.de [Department of Physiology, University of Tuebingen (Germany)

    2010-11-19

    Research highlights: {yields} The oncogenic transcription factor {beta}-catenin stimulates the Na{sup +}/K{sup +}-ATPase. {yields} {beta}-Catenin stimulates SGLT1 dependent Na{sup +}, glucose cotransport. {yields} The effects are independent of transcription. {yields} {beta}-Catenin sensitive transport may contribute to properties of proliferating cells. -- Abstract: {beta}-Catenin is a multifunctional protein stimulating as oncogenic transcription factor several genes important for cell proliferation. {beta}-Catenin-regulated genes include the serum- and glucocorticoid-inducible kinase SGK1, which is known to stimulate a variety of transport systems. The present study explored the possibility that {beta}-catenin influences membrane transport. To this end, {beta}-catenin was expressed in Xenopus oocytes with or without SGLT1 and electrogenic transport determined by dual electrode voltage clamp. As a result, expression of {beta}-catenin significantly enhanced the ouabain-sensitive current of the endogeneous Na{sup +}/K{sup +}-ATPase. Inhibition of vesicle trafficking by brefeldin A revealed that the stimulatory effect of {beta}-catenin on the endogenous Na{sup +}/K{sup +}-ATPase was not due to enhanced stability of the pump protein in the cell membrane. Expression of {beta}-catenin further enhanced glucose-induced current (Ig) in SGLT1-expressing oocytes. In the absence of SGLT1 Ig was negligible irrespective of {beta}-catenin expression. The stimulating effect of {beta}-catenin on both Na{sup +}/K{sup +} ATPase and SGLT1 activity was observed even in the presence of actinomycin D, an inhibitor of transcription. The experiments disclose a completely novel function of {beta}-catenin, i.e. the regulation of transport.

  6. Caffeine intake enhances the benefits of sodium glucose transporter 2 inhibitor.

    Science.gov (United States)

    Hashimoto, Yoshitaka; Tanaka, Muhei; Yamazaki, Masahiro; Nakano, Koji; Ushigome, Emi; Okada, Hiroshi; Oda, Yohei; Nakamura, Naoto; Fukui, Michiaki

    2016-10-01

    The effect of sodium glucose transporter 2 (SGLT-2) inhibitors is dependent on the glomerular filtration rate. It has been reported that caffeine intake increases glomerular filtration rate. However, the effect of caffeine intake on urinary glucose excretion in patients who take SGLT-2 inhibitors is unclear. Six patients with type 2 diabetes took part in a randomized, open-label, crossover pilot study. The patients took SGLT-2 inhibitors (ipragliflozin) for 9 days. On day 3, 6 and 9, the patients were assigned to one of three studies: Water 500, patients drank 500 mL of water in 3 h; Water 1500, patients drank 1500 mL of water in 3 h; and Caffeine 500, patients drank 500 mL of water with 400 mg of caffeine in 3 h. In all of the studies, the patients' urine was collected over a 6-h period. In addition, we enrolled 60 patients with type 2 diabetes who newly took SGLT-2 inhibitors in a 3-month follow-up cohort study to investigate the effect of caffeine intake on glucose control. Caffeine intake was evaluated using questionnaires. The 6-h median (interquartile range) urinary glucose excretion was 9.5 (8.5-9.7) g in Water 500, 12.2 (10.3-27.2) g in Water 1500 and 15.7 (11.4-21.4) g in Caffeine 500 (p = 0.005 vs Water 500). In the cohort study, multiple regression analysis demonstrated that log (caffeine intake) was associated with a change in HbA 1c (β = -0.299, p = 0.043) after adjusting for covariates. Caffeine intake enhanced the effect of SGLT-2 inhibitors. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Sugar regulation of SUGAR TRANSPORTER PROTEIN 1 (STP1) expression in Arabidopsis thaliana

    Science.gov (United States)

    Cordoba, Elizabeth; Aceves-Zamudio, Denise Lizeth; Hernández-Bernal, Alma Fabiola; Ramos-Vega, Maricela; León, Patricia

    2015-01-01

    Sugars regulate the expression of many genes at the transcriptional level. In Arabidopsis thaliana, sugars induce or repress the expression of >1800 genes, including the STP1 (SUGAR TRANSPORTER PROTEIN 1) gene, which encodes an H+/monosaccharide cotransporter. STP1 transcript levels decrease more rapidly after the addition of low concentrations of sugars than the levels of other repressed genes, such as DIN6 (DARK-INDUCED 6). We found that this regulation is exerted at the transcriptional level and is initiated by phosphorylatable sugars. Interestingly, the sugar signal that modulates STP1 expression is transmitted through a HEXOKINASE 1-independent signalling pathway. Finally, analysis of the STP1 5′ regulatory region allowed us to delimit a region of 309bp that contains the cis elements implicated in the glucose regulation of STP1 expression. Putative cis-acting elements involved in this response were identified. PMID:25281700

  8. The p38 mitogen-activated protein kinase inhibitor SB203580 reduces glucose turnover by the glucose transporter-4 of 3T3-L1 adipocytes in the insulin-stimulated state

    NARCIS (Netherlands)

    Bazuine, Merlijn; Carlotti, Françoise; Rabelink, Martijn J. W. E.; Vellinga, Jort; Hoeben, Rob C.; Maassen, J. Antonie

    2005-01-01

    Insulin induces a profound increase in glucose uptake in 3T3-L1 adipocytes through the activity of the glucose transporter-4 (GLUT4). Apart from GLUT4 translocation toward the plasma membrane, there is also an insulin-induced p38 MAPK-dependent step involved in the regulation of glucose uptake.

  9. MicroRNA-194 Modulates Glucose Metabolism and Its Skeletal Muscle Expression Is Reduced in Diabetes.

    Science.gov (United States)

    Latouche, Celine; Natoli, Alaina; Reddy-Luthmoodoo, Medini; Heywood, Sarah E; Armitage, James A; Kingwell, Bronwyn A

    2016-01-01

    The regulation of microRNAs (miRNAs) at different stages of the progression of type 2 diabetes mellitus (T2DM) and their role in glucose homeostasis was investigated. Microarrays were used to assess miRNA expression in skeletal muscle biopsies taken from healthy individuals and patients with pre-diabetes or T2DM, and insulin resistant offspring of rat dams fed a high fat diet during pregnancy. Twenty-three miRNAs were differentially expressed in patients with T2DM, and 7 in the insulin resistant rat offspring compared to their controls. Among these, only one miRNA was similarly regulated: miR-194 expression was significantly reduced by 25 to 50% in both the rat model and in human with pre-diabetes and established diabetes. Knockdown of miR-194 in L6 skeletal muscle cells induced an increase in basal and insulin-stimulated glucose uptake and glycogen synthesis. This occurred in conjunction with an increased glycolysis, indicated by elevated lactate production. Moreover, oxidative capacity was also increased as we found an enhanced glucose oxidation in presence of the mitochondrial uncoupler FCCP. When miR-194 was down-regulated in vitro, western blot analysis showed an increased phosphorylation of AKT and GSK3β in response to insulin, and an increase in expression of proteins controlling mitochondrial oxidative phosphorylation. Type 2 diabetes mellitus is associated with regulation of several miRNAs in skeletal muscle. Interestingly, miR-194 was a unique miRNA that appeared regulated across different stages of the disease progression, from the early stages of insulin resistance to the development of T2DM. We have shown miR-194 is involved in multiple aspects of skeletal muscle glucose metabolism from uptake, through to glycolysis, glycogenesis and glucose oxidation, potentially via mechanisms involving AKT, GSK3 and oxidative phosphorylation. MiR-194 could be down-regulated in patients with early features of diabetes as an adaptive response to facilitate tissue

  10. Sodium-glucose co-transporter type 2 inhibitors reduce evening home blood pressure in type 2 diabetes with nephropathy.

    Science.gov (United States)

    Takenaka, Tsuneo; Kishimoto, Miyako; Ohta, Mari; Tomonaga, Osamu; Suzuki, Hiromichi

    2017-05-01

    The effects of sodium-glucose co-transporter type 2 inhibitors on home blood pressure were examined in type 2 diabetes with nephropathy. The patients with diabetic nephropathy were screened from medical records in our hospitals. Among them, 52 patients who measured home blood pressure and started to take sodium-glucose co-transporter type 2 inhibitors were selected. Clinical parameters including estimated glomerular filtration rate, albuminuria and home blood pressure for 6 months were analysed. Sodium-glucose co-transporter type 2 inhibitors (luseogliflozin 5 mg/day or canagliflozin 100 mg/day) reduced body weight, HbA1c, albuminuria, estimated glomerular filtration rate and office blood pressure. Although sodium-glucose co-transporter type 2 inhibitors did not alter morning blood pressure, it reduced evening systolic blood pressure. Regression analyses revealed that decreases in evening blood pressure predicted decrements in albuminuria. The present data suggest that sodium-glucose co-transporter type 2 inhibitors suppress sodium overload during daytime to reduce evening blood pressure and albuminuria.

  11. In situ mouse carotid perfusion model: glucose and cholesterol transport in the eye and brain.

    Science.gov (United States)

    Cattelotte, Julie; André, Pascal; Ouellet, Mélissa; Bourasset, Fanchon; Scherrmann, Jean-Michel; Cisternino, Salvatore

    2008-08-01

    The in situ mouse brain perfusion method for measuring blood-brain barrier permeability was adapted to assess transport of solutes at the blood-brain and blood-eye barriers. The procedure was checked with radiolabeled markers in oxygenated bicarbonate-buffered fluid infused for 30 to 120 sec via a carotid artery. Vascular flow estimated with diazepam was 2.2-fold lower in the eye than in the brain. The vascular volume and the integrity markers sucrose and inulin indicated that a perfusion flow rate of 2.5 mL/min preserved the physical integrity of these organs. However, the brain vasculature integrity was more sensitive to acute perfusion pressure than the eye vasculature. The functional capacities of blood barriers were assessed with D-glucose; its transport followed Michaelis-Menten kinetics with an apparent K(m) of 7.6 mmol/L and a V(max) of 23 micromol/sec per g in the brain, and a K(m) of 22.9 mmol/L and a V(max) of 40 micromol/sec per g in the eye. The transport of cholesterol to the brain and eye was significantly enhanced by adding the Abca1 inhibitor probucol, suggesting an Abca1-mediated efflux at the mouse brain and eye blood barriers. Thus in situ carotid perfusion is suitable for elucidating transport processes at the blood-brain and blood-eye barriers.

  12. Assessment of insulin resistance in fructose-fed rats with 125I-6-deoxy-6-iodo-D-glucose, a new tracer of glucose transport

    International Nuclear Information System (INIS)

    Perret, Pascale; Slimani, Lotfi; Briat, Arnaud; Villemain, Daniele; Fagret, Daniel; Ghezzi, Catherine; Halimi, Serge; Demongeot, Jacques

    2007-01-01

    Insulin resistance, characterised by an insulin-stimulated glucose transport defect, is an important feature of the pre-diabetic state that has been observed in numerous pathological disorders. The purpose of this study was to assess variations in glucose transport in rats using 125 I-6-deoxy-6-iodo-D-glucose (6DIG), a new tracer of glucose transport proposed as an imaging tool to assess insulin resistance in vivo. Two protocols were performed, a hyperinsulinaemic-euglycaemic clamp and a normoinsulinaemic-normoglycaemic protocol, in awake control and insulin-resistant fructose-fed rats. The tracer was injected at steady state, and activity in 11 tissues and the blood was assessed ex vivo at several time points. A multicompartmental mathematical model was developed to obtain fractional transfer coefficients of 6DIG from the blood to the organs. Insulin sensitivity of fructose-fed rats, estimated by the glucose infusion rate, was reduced by 40% compared with control rats. At steady state, 6DIG uptake was significantly stimulated by insulin in insulin-sensitive tissues of control rats (basal versus insulin: diaphragm, p < 0.01; muscle, p < 0.05; heart, p < 0.001), whereas insulin did not stimulate 6DIG uptake in insulin-resistant fructose-fed rats. Moreover, in these tissues, the fractional transfer coefficients of entrance were significantly increased with insulin in control rats (basal vs insulin: diaphragm, p < 0.001; muscle, p < 0.001; heart, p < 0.01) whereas no significant changes were observed in fructose-fed rats. This study sets the stage for the future use of 6DIG as a non-invasive means for the evaluation of insulin resistance by nuclear imaging. (orig.)

  13. Glucose transportation in the brain and its impairment in Huntington disease: one more shade of the energetic metabolism failure?

    Science.gov (United States)

    Morea, Veronica; Bidollari, Eris; Colotti, Gianni; Fiorillo, Annarita; Rosati, Jessica; De Filippis, Lidia; Squitieri, Ferdinando; Ilari, Andrea

    2017-07-01

    Huntington's disease (HD) or Huntington's chorea is the most common inherited, dominantly transmitted, neurodegenerative disorder. It is caused by increased CAG repeats number in the gene coding for huntingtin (Htt) and characterized by motor, behaviour and psychiatric symptoms, ultimately leading to death. HD patients also exhibit alterations in glucose and energetic metabolism, which result in pronounced weight loss despite sustained calorie intake. Glucose metabolism decreases in the striatum of all the subjects with mutated Htt, but affects symptom presentation only when it drops below a specific threshold. Recent evidence points at defects in glucose uptake by the brain, and especially by neurons, as a relevant component of central glucose hypometabolism in HD patients. Here we review the main features of glucose metabolism and transport in the brain in physiological conditions and how these processes are impaired in HD, and discuss the potential ability of strategies aimed at increasing intracellular energy levels to counteract neurological and motor degeneration in HD patients.

  14. Contraction-stimulated glucose transport in muscle is controlled by AMPK and mechanical stress but not sarcoplasmatic reticulum Ca2+ release

    Directory of Open Access Journals (Sweden)

    Thomas E. Jensen

    2014-10-01

    Full Text Available Understanding how muscle contraction orchestrates insulin-independent muscle glucose transport may enable development of hyperglycemia-treating drugs. The prevailing concept implicates Ca2+ as a key feed forward regulator of glucose transport with secondary fine-tuning by metabolic feedback signals through proteins such as AMPK. Here, we demonstrate in incubated mouse muscle that Ca2+ release is neither sufficient nor strictly necessary to increase glucose transport. Rather, the glucose transport response is associated with metabolic feedback signals through AMPK, and mechanical stress-activated signals. Furthermore, artificial stimulation of AMPK combined with passive stretch of muscle is additive and sufficient to elicit the full contraction glucose transport response. These results suggest that ATP-turnover and mechanical stress feedback are sufficient to fully increase glucose transport during muscle contraction, and call for a major reconsideration of the established Ca2+ centric paradigm.

  15. A putative plastidic glucose translocator is expressed in heterotrophic tissues that do not contain starch, during olive (Olea europea L.) fruit ripening.

    Science.gov (United States)

    Butowt, Rafal; Granot, David; Rodríguez-García, María Isabel

    2003-11-01

    Metabolite-specific transporters are present in the inner membrane of the plastid envelope allowing transport between the plastid and other cellular compartments. A plastidic glucose translocator (pGlcT) in leaf mesophyll cells transports glucose from chloroplast stroma to the cytosol after amylolytic starch degradation at night. Here we report the cloning of a pGlcT expressed in olive fruits (Olea europea L.). Our results showed high expression of pGlcT in non-green heterotrophic fruit tissues. Expression of pGlcT in olive fruits was somewhat higher compared to leaves, and continued until the black, mature fruit stage. We cloned part of tomato pGlcT and found that it is also expressed throughout fruit development implying a role for pGlcT in heterotrophic tissues. Light and electron microscopic characterization of plastid structural changes during olive fruit ripening revealed the transition of chloroplast-like plastids into starchless, non-green plastids; in mature olive fruits only chromoplasts were present. Together, these findings suggest that olive pGlcT is abundant in chromoplasts during structural changes, and provide evidence that pGlcT may play different physiological roles in ripening fruits and possibly in other non-photosynthetic organs.

  16. Metabolic control of Clostridium thermocellum via inhibition of hydrogenase activity and the glucose transport rate.

    Science.gov (United States)

    Li, Hsin-Fen; Knutson, Barbara L; Nokes, Sue E; Lynn, Bert C; Flythe, Michael D

    2012-02-01

    Clostridium thermocellum has the ability to catabolize cellulosic biomass into ethanol, but acetic acid, lactic acid, carbon dioxide, and hydrogen gas (H(2)) are also produced. The effect of hydrogenase inhibitors (H(2), carbon monoxide (CO), and methyl viologen) on product selectivity was investigated. The anticipated effect of these hydrogenase inhibitors was to decrease acetate production. However, shifts to ethanol and lactate production are also observed as a function of cultivation conditions. When the sparge gas of cellobiose-limited chemostat cultures was switched from N(2) to H(2), acetate declined, and ethanol production increased 350%. In resting cell suspensions, lactate increased when H(2) or CO was the inhibitor or when the cells were held at elevated hyperbaric pressure (6.8 atm). In contrast, methyl-viologen-treated resting cells produced twice as much ethanol as the other treatments. The relationship of chemostat physiology to methyl viologen inhibition was revealed by glucose transport experiments, in which methyl viologen decreased the rate of glucose transport by 90%. C. thermocellum produces NAD(+) from NADH by H(2), lactate, and ethanol production. When the hydrogenases were inhibited, the latter two products increased. However, excess substrate availability causes fructose 1,6-diphosphate, the glycolytic intermediate that triggers lactate production, to increase. Compensatory ethanol production was observed when the chemostat fluid dilution rate or methyl viologen decreased substrate transport. This research highlights the complex effects of high concentrations of dissolved gases in fermentation, which are increasingly envisioned in microbial applications of H(2) production for the conversion of synthetic gases to chemicals.

  17. [Quercetin regulates cell cycle-related gene expression in a model of glucose-oxygen deprivation in astrocytes].

    Science.gov (United States)

    Yao, Fang; Zhang, Lanlan; Yuan, Zhaohu; Zeng, Yong; Wu, Bingyi

    2013-09-01

    To study the effect of quercetin on gene expression in astrocytes after glucose-oxygen deprivation and the underlying mechanism. The primary cultured astrocytes were randomly divided into glucose-oxygen deprivation group (only treated with glucose-oxygen deprivation for 4 hours) and glucose-oxygen deprivation combined with quercetin-treated group (glucose-oxygen deprivation for 4 hours combined with quercetin treatment for 24 hours). Their mRNA expressions were analyzed by the large-scale oligo microarray. The differential genes obtained were further confirmed by real-time quantitative PCR (qRT-PCR). Compared with the glucose-oxygen deprivation group, the glucose-oxygen deprivation combined with quercetin-treated group presented the changes in the expressions of 31 genes that were related to cell cycle, of which 5 genes were up-regulated and 26 were down-regulated. Six of those differential genes were confirmed by qRT-PCR and the result of their differential expressions was consistent with that by large-scale oligo microarray. Quercetin can regulate some of cell cycle-related genes in astrocytes after glucose-oxygen deprivation.

  18. Transcriptional expression changes of glucose metabolism genes after exercise in thoroughbred horses.

    Science.gov (United States)

    Gim, Jeong-An; Ayarpadikannan, Selvam; Eo, Jungwoo; Kwon, Yun-Jeong; Choi, Yuri; Lee, Hak-Kyo; Park, Kyung-Do; Yang, Young Mok; Cho, Byung-Wook; Kim, Heui-Soo

    2014-08-15

    Physical exercise induces gene expression changes that trigger glucose metabolism pathways in organisms. In the present study, we monitored the expression levels of LDHA (lactate dehydrogenase) and GYS1 (glycogen synthase 1) in the blood, to confirm the roles of these genes in exercise physiology. LDHA and GYS1 are related to glucose metabolism and fatigue recovery, and these processes could elicit economically important traits in racehorses. We collected blood samples from three retired thoroughbred racehorses, pre-exercise and immediately after 30 min of exercise. We extracted total RNA and small RNA (≤ 200 nucleotide-long) from the blood, and assessed the expression levels of LDHA, GYS1, and microRNAs (miRNAs), by using qRT-PCR. We showed that LDHA and GYS1 were down-regulated, whereas eca-miR-33a and miR-17 were up-regulated, after exercise. We used sequences from the 3' UTR of LDHA and GYS1, containing eca-miR-33a and miR-17 binding sites, to observe the down-regulation activity of each gene expression. We observed that the two miRNAs, namely, eca-miR-33a and miR-17, inhibited LDHA and GYS1 expression via binding to the 3' UTR sequences of each gene. Our results indicate that eca-miR-33a and miR-17 play important roles in the glucose metabolism pathway. In addition, our findings provide a basis for further investigation of the exercise metabolism of racehorses. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Reduced connexin43 expression correlates with c-Src activation, proliferation, and glucose uptake in reactive astrocytes after an excitotoxic insult.

    Science.gov (United States)

    Gangoso, Ester; Ezan, Pascal; Valle-Casuso, José Carlos; Herrero-González, Sandra; Koulakoff, Annette; Medina, Jose M; Giaume, Christian; Tabernero, Arantxa

    2012-12-01

    In diverse brain pathologies, astrocytes become reactive and undergo profound phenotypic changes. Connexin43 (Cx43), the main gap junction channel-forming protein in astrocytes, is one of the proteins modified in reactive astrocytes. Downregulation of Cx43 in cultured astrocytes activates c-Src, promotes proliferation, and increases the rate of glucose uptake; however, so far there have been no studies examining whether this cascade of events takes place in reactive astrocytes. In this work, we analyzed this pathway after a cortical lesion induced by a kainic acid injection. As previously described, astrocytes reacted to the lesion with an increase in glial fibrillary acidic protein and a decrease in Cx43 expression. Some of these reactive astrocytes proliferated, as estimated by bromodeoxyuridine incorporation and cyclins D1 and D3 upregulation. In addition, the expression of the glucose transporter GLUT-3 and the enzyme responsible for glucose phosphorylation, Type II hexokinase (Hx-2), were induced in reactive astrocytes, suggesting an increased glucose uptake. Previous in vitro studies reported that c-Src is the link between Cx43 and glucose uptake and proliferation in astrocytes. Here, we found that c-Src activity increased in the lesioned area. c-Src activation and Cx43 downregulation preceded the peak of Hx-2 and cyclin D3 expression, suggesting that c-Src could mediate the effect of Cx43 on glucose uptake and proliferation in reactive astrocytes after an excitotoxic insult. Interestingly, we identify c-Src, GLUT-3, and Hx-2 in the signaling mechanisms involved in the reaction of astroglia to injury. Altogether these data contribute to identify new therapeutical targets to enhance astrocyte neuroprotective activities. Copyright © 2012 Wiley Periodicals, Inc.

  20. Multiple signalling pathways redundantly control glucose transporter GLUT4 gene transcription in skeletal muscle

    DEFF Research Database (Denmark)

    Murgia, Marta; Elbenhardt Jensen, Thomas; Cusinato, Marzia

    2009-01-01

    Increased GLUT4 expression in skeletal muscle is an important benefit of regular exercise, resulting in improved insulin sensitivity and glucose tolerance. The Ca2+/calmodulin-dependent-kinase II (CaMKII), calcineurin and AMPK pathways have been implicated in GLUT4 gene regulation based...... on pharmacological evidence. Here, we have used a more specific genetic approach to establish the relative role of the three pathways in fast and slow muscles. Plasmids coding for protein inhibitors of CaMKII or calcineurin were co-transfected in vivo with a GLUT4 enhancer-reporter construct either in normal mice...... or in mice expressing a dominant negative AMPK mutant. GLUT4 reporter activity was not inhibited in the slow soleus muscle by blocking either CaMKII or calcineurin alone, but was inhibited by blocking both pathways. GLUT4 reporter activity was likewise unchanged in the soleus of dnAMPK mice...

  1. Glucose increases interleukin-12 gene expression and production in stimulated peripheral blood mononuclear cells of type 2 diabetes patients

    Directory of Open Access Journals (Sweden)

    Chien-Ming Chu

    2014-10-01

    Full Text Available Background: Lipopolysaccharide (LPS-stimulated peripheral blood mononuclear cells (PBMCs of type 2 diabetes patients produce more interleukin (IL-12 under glucose treatment. The aim of this study was to determine whether increased IL-12 response in hyperglycemic LPS-stimulated PBMCs is due to increased gene expression or osmolarity. Methods: LPS-stimulated PBMCs of 13 type 2 diabetes patients and 8 healthy controls were used for culture in the presence or absence of glucose or mannitol for 24 h. The IL-12 gene expressions of PBMCs and IL-12 protein levels in supernatants were evaluated. Results: After 24 h, the stimulated PBMCs of diabetes patients expressed more IL-12 mRNA and produced more IL-12 protein following glucose treatment than those without glucose treatment and with mannitol treatment. Stimulated PBMCs of controls did not express more IL-12 mRNA and produce more IL-12 protein following glucose treatment than those without glucose treatment and with mannitol treatment. Conclusions: Glucose increases the IL-12 production in stimulated PBMCs of diabetes patients through increased IL-12 gene expression.

  2. Schisandra polysaccharide increased glucose consumption by up-regulating the expression of GLUT-4.

    Science.gov (United States)

    Jin, Dun; Zhao, Ting; Feng, Wei-Wei; Mao, Guang-Hua; Zou, Ye; Wang, Wei; Li, Qian; Chen, Yao; Wang, Xin-Tong; Yang, Liu-Qing; Wu, Xiang-Yang

    2016-06-01

    In our previous study, a polysaccharide was extracted from Schisandra Chinensis (Trucz.) Baill and found with anti-diabetic effects. The aim of this study was to investigate the anti-diabetic effects of the low weight molecular polysaccharide (SCPP11) purified from crude Schisandra polysaccharide and illustrate the underlying mechanism in buffalo rat liver cells. The insulin resistance model of BRL cells was established by incubating with insulin solution for 24h. The effects of SCPP11 on regulating related protein and mRNA expression in an insulin and AMPK signal pathway were investigated by western blot and RT-PCR analysis. SCPP11 showed no cytotoxicity to BRL cells and could improve the glucose consumption in BRL cells. SCPP11 increased the protein expression of Akt, p-AMPK and GLUT-4 in BRL cells. Moreover, SCPP11 could enhance the mRNA expression levels of IRS-1, PI3K, Akt, GLUT-4, AMPKα and PPAR-γ in BRL cells at the same time. In conclusion, SCPP11 possessed effects in improving glucose consumption by up-regulating the expression of GLUT-4 which might occur via insulin and AMPK signal pathway and could be a potential functional food to prevent and mitigate the insulin resistance condition. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Contraction-stimulated glucose transport in muscle is controlled by AMPK and mechanical stress but not sarcoplasmatic reticulum Ca2+ release

    DEFF Research Database (Denmark)

    Jensen, Thomas Elbenhardt; Sylow, Lykke; Rose, Adam John

    2014-01-01

    signals through proteins such as AMPK. Here, we demonstrate in incubated mouse muscle that Ca(2+) release is neither sufficient nor strictly necessary to increase glucose transport. Rather, the glucose transport response is associated with metabolic feedback signals through AMPK, and mechanical stress......-activated signals. Furthermore, artificial stimulation of AMPK combined with passive stretch of muscle is additive and sufficient to elicit the full contraction glucose transport response. These results suggest that ATP-turnover and mechanical stress feedback are sufficient to fully increase glucose transport...

  4. Production of d-allulose from d-glucose by Escherichia coli transformant cells co-expressing d-glucose isomerase and d-psicose 3-epimerase genes.

    Science.gov (United States)

    Zhang, Wenli; Li, Hao; Jiang, Bo; Zhang, Tao; Mu, Wanmeng

    2017-08-01

    d-Allulose is a novel and low-calorie rare monosaccharide that is a C-3 epimer of d-fructose. Because of its excellent physiological properties and commercial potential, d-allulose has attracted researchers' interests. Based on the Izumoring strategy, d-allulose is converted from d-fructose by d-psicose 3-epimerase (DPEase), while d-fructose is converted from d-glucose by d-glucose isomerase (GIase). In this study, we created a cellular system capable of converting d-glucose to d-allulose in a one-step process that co-expressed the GIase from Acidothermus cellulolyticus and the DPEase from Dorea sp. CAG. The co-expression plasmid pETDuet-Dosp-DPE/Acce-GI was generated and transformed into Escherichia coli BL21(DE3) cells. The recombinant co-expression cells exhibited maximum catalytic activity at pH 6.5 and 75 °C. These cells were thermostable at less than 60 °C. The addition of Co 2+ significantly increased the catalytic activity by 10.8-fold. When the reaction equilibrium was reached, the ratio of d-glucose, d-fructose and d-allulose was approximately 6.5:7:3, respectively. A recombinant co-expression strain that catalysed the bioconversion of d-allulose from d-glucose in a one-step process was created and characterised. When adding 500 g L -1 d-glucose as a substrate, 204.3 g L -1 d-fructose and 89.1 g L -1 d-allulose were produced. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  5. Exercise-induced increase in glucose transport, GLUT-4, and VAMP-2 in plasma membrane from human muscle

    DEFF Research Database (Denmark)

    Kristiansen, S; Hargreaves, Mark; Richter, Erik

    1996-01-01

    contractions may induce trafficking of GLUT-4-containing vesicles via a mechanism similar to neurotransmitter release. Our results demonstrate for the first time exercise-induced translocation of GLUT-4 and VAMP-2 to the plasma membrane of human muscle and increased sarcolemmal glucose transport.......A major effect of muscle contractions is an increase in sarcolemmal glucose transport. We have used a recently developed technique to produce sarcolemmal giant vesicles from human muscle biopsy samples obtained before and after exercise. Six men exercised for 10 min at 50% maximal O2 uptake (Vo2max...

  6. Sodium-glucose co-transporter-2 inhibitors and euglycemic ketoacidosis: Wisdom of hindsight

    Directory of Open Access Journals (Sweden)

    Awadhesh Kumar Singh

    2015-01-01

    Full Text Available Sodium-glucose co-transporter-2 inhibitors (SGLT-2i are newly approved class of oral anti-diabetic drugs, in the treatment of type 2 diabetes, which reduces blood glucose through glucouresis via the kidney, independent, and irrespective of available pancreatic beta-cells. Studies conducted across their clinical development program found, a modest reduction in glycated hemoglobin ranging from −0.5 to −0.8%, without any significant hypoglycemia. Moreover, head-to-head studies versus active comparators yielded comparable efficacy. Interestingly, weight and blood pressure reduction were additionally observed, which was not only consistent but significantly superior to active comparators, including metformin, sulfonylureas, and dipeptydylpeptide-4 inhibitors. Indeed, these additional properties makes this class a promising oral anti-diabetic drug. Surprisingly, a potentially fatal unwanted side effect of diabetic ketoacidosis has been noted with its widespread use, albeit rarely. Nevertheless, this has created a passé among the clinicians. This review is an attempt to pool those ketosis data emerging with SGLT-2i, and put a perspective on its implicated mechanism.

  7. Chlorogenic Acid Maintains Glucose Homeostasis through Modulating the Expression of SGLT-1, GLUT-2, and PLG in Different Intestinal Segments of Sprague-Dawley Rats Fed a High-Fat Diet.

    Science.gov (United States)

    Peng, Bing Jie; Zhu, Qi; Zhong, Ying Li; Xu, Shi Hao; Wang, Zheng

    2015-12-01

    To reveal the effects and related mechanisms of chlorogenic acid (CGA) on intestinal glucose homeostasis. Forty male Sprague-Dawley rats were randomly and equally divided into four groups: normal chow (NC), high-fat diet (HFD), HFD with low-dose CGA (20 mg/kg, HFD-LC), and HFD with high-dose CGA (90 mg/kg, HFD-HC). The oral glucose tolerance test was performed, and fast serum insulin (FSI) was detected using an enzyme-linked immunosorbent assay. The mRNA expression levels of glucose transporters (Sglt-1 and Glut-2) and proglucagon (Plg) in different intestinal segments (the duodenum, jejunum, ileum, and colon) were analyzed using quantitative real-time polymerase chain reaction. SGLT-1 protein and the morphology of epithelial cells in the duodenum and jejunum was localized by using immunofluorescence. At both doses, CGA ameliorated the HFD-induced body weight gain, maintained FSI, and increased postprandial 30-min glucagon-like peptide 1 secretion. High-dose CGA inhibited the HFD-induced elevation in Sglt-1 expression. Both CGA doses normalized the HFD-induced downregulation of Glut-2 and elevated the expression of Plg in all four intestinal segments. An HFD can cause a glucose metabolism disorder in the rat intestine and affect body glucose homeostasis. CGA can modify intestinal glucose metabolism by regulating the expression of intestinal glucose transporters and Plg, thereby controlling the levels of blood glucose and insulin to maintain glucose homeostasis. Copyright © 2015 The Editorial Board of Biomedical and Environmental Sciences. Published by China CDC. All rights reserved.

  8. β-actin shows limited mobility and is only required for supraphysiological insulin-stimulated glucose transport in young adult soleus muscle

    DEFF Research Database (Denmark)

    Madsen, Agnete Louise Bjerregaard; Knudsen, Jonas Roland; Henriquez-Olguin, Carlos

    2018-01-01

    in soleus but not in EDL of young adult mice. Contraction-stimulated glucose transport trended towards the same pattern, but the glucose transport phenotype disappeared in soleus muscles from mature adult mice. No genotype-related differences were found in body composition, glucose tolerance or by indirect...... in mature skeletal muscle. Neither dependency of glucose transport on β-actin nor actin reorganization upon glucose transport have been tested in mature muscle. To investigate the role of β-actin in fully differentiated muscle, we have performed a detailed characterization of wildtype and muscle-specific β...... calorimetry measurements. To evaluate β-actin mobility in mature muscle, we electroporated GFP-β-actin into FDB muscle fibers and measured FRAP. GFP-β-actin showed limited unstimulated mobility and no changes after insulin stimulation. In conclusion, β-actin is not required for glucose transport regulation...

  9. Characterization of the transport activity of SGLT2/MAP17, the renal low-affinity Na+-glucose cotransporter.

    Science.gov (United States)

    Coady, Michael J; Wallendorff, Bernadette; Lapointe, Jean-Yves

    2017-08-01

    The cotransporter SGLT2 is responsible for 90% of renal glucose reabsorption, and we recently showed that MAP17 appears to work as a required β-subunit. We report in the present study a detailed functional characterization of human SGLT2 in coexpression with human MAP17 in Xenopus laevis oocytes. Addition of external glucose generates a large inward current in the presence of Na, confirming an electrogenic transport mechanism. At a membrane potential of -50 mV, SGLT2 affinity constants for glucose and Na are 3.4 ± 0.4 and 18 ± 6 mM, respectively. The change in the reversal potential of the cotransport current as a function of external glucose concentration clearly confirms a 1:1 Na-to-glucose transport stoichiometry. SGLT2 is selective for glucose and α-methylglucose but also transports, to a lesser extent, galactose and 3- O -methylglucose. SGLT2 can be inhibited in a competitive manner by phlorizin ( K i = 31 ± 4 nM) and by dapagliflozin ( K i = 0.75 ± 0.3 nM). Similarly to SGLT1, SGLT2 can be activated by Na, Li, and protons. Pre-steady-state currents for SGLT2 do exist but are small in amplitude and relatively fast (a time constant of ~2 ms). The leak current defined as the phlorizin-sensitive current in the absence of substrate was extremely small in the case of SGLT2. In summary, in comparison with SGLT1, SGLT2 has a lower affinity for glucose, a transport stoichiometry of 1:1, very small pre-steady-state and leak currents, a 10-fold higher affinity for phlorizin, and an affinity for dapagliflozin in the subnanomolar range. Copyright © 2017 the American Physiological Society.

  10. Improving L-arabinose utilization of pentose fermenting Saccharomyces cerevisiae cells by heterologous expression of L-arabinose transporting sugar transporters

    Directory of Open Access Journals (Sweden)

    Boles Eckhard

    2011-10-01

    Full Text Available Abstract Background Hydrolysates of plant biomass used for the production of lignocellulosic biofuels typically contain sugar mixtures consisting mainly of D-glucose and D-xylose, and minor amounts of L-arabinose. The yeast Saccharomyces cerevisiae is the preferred microorganism for the fermentative production of ethanol but is not able to ferment pentose sugars. Although D-xylose and L-arabinose fermenting S. cerevisiae strains have been constructed recently, pentose uptake is still a limiting step in mixed sugar fermentations. Results Here we described the cloning and characterization of two sugar transporters, AraT from the yeast Scheffersomyces stipitis and Stp2 from the plant Arabidopsis thaliana, which mediate the uptake of L-arabinose but not of D-glucose into S. cerevisiae cells. A yeast strain lacking all of its endogenous hexose transporter genes and expressing a bacterial L-arabinose utilization pathway could no longer take up and grow with L-arabinose as the only carbon source. Expression of the heterologous transporters supported uptake and utilization of L-arabinose especially at low L-arabinose concentrations but did not, or only very weakly, support D-glucose uptake and utilization. In contrast, the S. cerevisiae D-galactose transporter, Gal2, mediated uptake of both L-arabinose and D-glucose, especially at high concentrations. Conclusions Using a newly developed screening system we have identified two heterologous sugar transporters from a yeast and a plant which can support uptake and utilization of L-arabinose in L-arabinose fermenting S. cerevisiae cells, especially at low L-arabinose concentrations.

  11. Construction of bioartificial renal tubule assist device in vitro and its function of transporting sodium and glucose.

    Science.gov (United States)

    Dong, Xinggang; Chen, Jianghua; He, Qiang; Yang, Yi; Zhang, Wei

    2009-08-01

    To explore a new way of constructing bioartificial renal tubule assist device (RAD) in vitro and its function of transporting sodium (Na(+)) and glucose and to evaluate the application of atomic force microscope in the RAD construction, rat renal tubular epithelial cell line NRK-52E was cultured in vitro, seeded onto the outer surfaces of hollow fibers in a bioreactor, and then cultured for two weeks to construct RAD. Bioreactor hollow fibers without NRK-52E cells were used as control. The morphologies of attached cells were observed with scanning electron microscope, and the junctions of cells and polysulfone membrane were observed with atomic force microscope. Transportation of Na(+) and glucose was measured. Oubaine and phlorizin were used to inhibit the transporting property. The results showed that NRK-52E cells and polysulfone membrane were closely linked, as observed under atomic force microscope. After exposure to oubaine and phlorizin, transporting rates of Na(+) and glucose were decreased significantly in the RAD group as compared with that in the control group (Pconstructed successfully in vitro, and it is able to selectively transport Na(+) and glucose.

  12. Transmembrane Domain Single-Nucleotide Polymorphisms Impair Expression and Transport Activity of ABC Transporter ABCG2

    NARCIS (Netherlands)

    Sjostedt, N.; Heuvel, J.J.M.W. van den; Koenderink, J.B.; Kidron, H.

    2017-01-01

    PURPOSE: To study the function and expression of nine naturally occurring single-nucleotide polymorphisms (G406R, F431L, S441N, P480L, F489L, M515R, L525R, A528T and T542A) that are predicted to reside in the transmembrane regions of the ABC transporter ABCG2. METHODS: The transport activity of the

  13. The apple polyphenol phloretin inhibits breast cancer cell migration and proliferation via inhibition of signals by type 2 glucose transporter

    Directory of Open Access Journals (Sweden)

    Kuan-Hsun Wu

    2018-01-01

    Full Text Available Human triple-negative breast cancer (TNBC is the most aggressive and poorly understood subclass of breast cancer. Glucose transporters (GLUTs are required for glucose uptake in malignant cancer cells and are ideal targets for cancer therapy. To determine whether the inhibition of GLUTs could be used in TNBC cell therapy, the apple polyphenol phloretin (Ph was used as a specific antagonist of GLUT2 protein function in human TNBC cells. Interestingly, we found that Ph (10–150 μM, for 24 h inhibited cell growth and arrested the cell cycle in MDA-MB-231 cells in a p53 mutant-dependent manner, which was confirmed by pre-treatment of the cells with a p53-specific dominant-negative expression vector. We also found that Ph treatment (10–150 μM, for 24 h significantly decreased the migratory activity of the MDA-MB-231 cells through the inhibition of paxillin/FAK, Src, and alpha smooth muscle actin (α-sMA and through the activation of E-cadherin. Furthermore, the anti-tumorigenic effect of Ph (10, 50 mg/kg or DMSO twice a week for six weeks was demonstrated in vivo using BALB/c nude mice bearing MDA-MB-231 tumor xenografts. A decrease in N-cadherin, vimentin and an increase in p53, p21 and E-cadherin were detected in the tumor tissues. In conclusion, inhibition of GLUT2 by the apple polyphenol Ph could potentially suppress TNBC tumor cell growth and metastasis.

  14. Water transport by Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS). The dependence of substrate size studied at high resolution

    DEFF Research Database (Denmark)

    Zeuthen, Thomas; Belhage, Bo; Zeuthen, Emil

    2005-01-01

    -analogue alpha-MDG (MW 194); using the larger sugar arbutin (MW 272) this number was reduced by a factor of at least 0.86+/-0.03 (15). For the human SGLT1 the respective numbers were 234+/-12 (18) and 0.85+/-0.8 (7). For NIS, 253+/-16 (12) water molecules were cotransported for each 2 Na+ and 1 thiocyanate (SCN......The relation between substrate and water transport was studied in Na+-coupled cotransporters of glucose (SGLT1) and of iodide (NIS) expressed in Xenopus oocytes. The water transport was monitored from changes in oocyte volume at a resolution of 20 pl, more than one order of magnitude better than...... of cotransport was changed by isosmotic application of substrate, by rapid changes in clamp voltage, or by poisoning. Transport of larger substrates gave rise to less water transport. For the rabbit SGLT1, 378+/-20 (n=18 oocytes) water molecules were cotransported along with the 2 Na+ ions and the glucose...

  15. Disruption of microtubules in rat skeletal muscle does not inhibit insulin- or contraction-stimulated glucose transport

    DEFF Research Database (Denmark)

    Ai, Hua; Ralston, Evelyn; Lauritzen, Hans P M M

    2003-01-01

    found in all muscle fibers. Here, we test whether microtubules are required mediators of the effect of insulin and contractions. In three different incubated rat muscles with distinct fiber type composition, depolymerization of microtubules with colchicine for ...- or contraction-stimulated 2-deoxyglucose transport or force production. On the contrary, colchicine at least partially prevented the approximately 30% decrease in insulin-stimulated transport that specifically developed during 8 h of incubation in soleus muscle but not in flexor digitorum brevis...... or epitrochlearis muscles. In contrast, nocodazole, another microtubule-disrupting drug, rapidly and dose dependently blocked insulin- and contraction-stimulated glucose transport. A similar discrepancy between colchicine and nocodazole was also found in their ability to block glucose transport in muscle giant...

  16. Heterologous expression and biochemical characterization of glucose isomerase from Thermobifida fusca.

    Science.gov (United States)

    Deng, Hui; Chen, Sheng; Wu, Dan; Chen, Jian; Wu, Jing

    2014-06-01

    Glucose isomerase (GIase) catalyzes the isomerization of D-glucose to D-fructose. The GIase from Thermobifida fusca WSH03-11 was expressed in Escherichia coli BL21(DE3), and the purified enzyme took the form of a tetramer in solution and displayed a pI value of 5.05. The temperature optimum of GIase was 80 °C and its half life was about 2 h at 80 °C or 15 h at 70 °C. The pH optimum of GIase was 10 and the enzyme retained 95 % activity over the pH range of 5-10 after incubating at 4 °C for 24 h. Kinetic studies showed that the K m and K cat values of the enzyme are 197 mM and 1,688 min(-1), respectively. The maximum conversion yield of glucose (45 %, w/v) to fructose of the enzyme was 53 % at pH 7.5 and 70 °C. The present study provides the basis for the industrial application of recombinant T. fusca GIase in the production of high fructose syrup.

  17. Molecular cloning, expression and characterization of a bovine serotonin transporter

    DEFF Research Database (Denmark)

    Mortensen, O V; Kristensen, A S; Rudnick, G

    1999-01-01

    The serotonin transporter (SERT) is a member of a highly homologous family of sodium/chloride dependent neurotransmitter transporters responsible for reuptake of biogenic amines from the extracellular fluid. SERT constitutes the pharmacological target of several clinically important antidepressan......-methylenedioxymethamphetamine (MDMA) was mainly unchanged. RT-PCR amplification of RNA from different tissues demonstrated expression of SERT in placenta, brain stem, bone marrow, kidney, lung, heart, adrenal gland, liver, parathyroid gland, thyroid gland, small intestine and pancreas....

  18. Sodium-glucose co-transporter 2 (SGLT2 inhibitors: a growing class of anti-diabetic agents

    Directory of Open Access Journals (Sweden)

    Eva M Vivian

    2014-12-01

    Full Text Available Although several treatment options are available to reduce hyperglycemia, only about half of individuals with diagnosed diabetes mellitus (DM achieve recommended glycemic targets. New agents that reduce blood glucose concentrations by novel mechanisms and have acceptable safety profiles are needed to improve glycemic control and reduce the complications associated with type 2 diabetes mellitus (T2DM. The renal sodium-glucose co-transporter 2 (SGLT2 is responsible for reabsorption of most of the glucose filtered by the kidney. Inhibitors of SGLT2 lower blood glucose independent of the secretion and action of insulin by inhibiting renal reabsorption of glucose, thereby promoting the increased urinary excretion of excess glucose. Canagliflozin, dapagliflozin, and empagliflozin are SGLT2 inhibitors approved as treatments for T2DM in the United States, Europe, and other countries. Canagliflozin, dapagliflozin, and empagliflozin increase renal excretion of glucose and improve glycemic parameters in patients with T2DM when used as monotherapy or in combination with other antihyperglycemic agents. Treatment with SGLT2 inhibitors is associated with weight reduction, lowered blood pressure, and a low intrinsic propensity to cause hypoglycemia. Overall, canagliflozin, dapagliflozin, and empagliflozin are well tolerated. Cases of genital infections and, in some studies, urinary tract infections have been more frequent in canagliflozin-, dapagliflozin-, and empagliflozin-treated patients compared with those receiving placebo. Evidence from clinical trials suggests that SGLT2 inhibitors are a promising new treatment option for T2DM.

  19. Fat gain with physical detraining is correlated with increased glucose transport and oxidation in periepididymal white adipose tissue in rats

    Energy Technology Data Exchange (ETDEWEB)

    Sertié, R.A.L.; Andreotti, S. [Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil); Proença, A.R.G. [Laboratório de Biotecnologia, Faculdade de Ciências Aplicadas, Universidade Estadual de Campinas, Limeira, SP (Brazil); Campaña, A.B.; Lima, F.B. [Departamento de Fisiologia e Biofísica, Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo, SP (Brazil)

    2015-05-26

    As it is a common observation that obesity tends to occur after discontinuation of exercise, we investigated how white adipocytes isolated from the periepididymal fat of animals with interrupted physical training transport and oxidize glucose, and whether these adaptations support the weight regain seen after 4 weeks of physical detraining. Male Wistar rats (45 days old, weighing 200 g) were divided into two groups (n=10): group D (detrained), trained for 8 weeks and detrained for 4 weeks; and group S (sedentary). The physical exercise was carried out on a treadmill for 60 min/day, 5 days/week for 8 weeks, at 50-60% of the maximum running capacity. After the training protocol, adipocytes isolated from the periepididymal adipose tissue were submitted to glucose uptake and oxidation tests. Adipocytes from detrained animals increased their glucose uptake capacity by 18.5% compared with those from sedentary animals (P<0.05). The same cells also showed a greater glucose oxidation capacity in response to insulin stimulation (34.55%) compared with those from the S group (P<0.05). We hypothesize that, owing to the more intense glucose entrance into adipose cells from detrained rats, more substrate became available for triacylglycerol synthesis. Furthermore, this increased glucose oxidation rate allowed an increase in energy supply for triacylglycerol synthesis. Thus, physical detraining might play a role as a possible obesogenic factor for increasing glucose uptake and oxidation by adipocytes.

  20. Glucose Metabolism Gene Expression Patterns and Tumor Uptake of 18F-Fluorodeoxyglucose After Radiation Treatment

    International Nuclear Information System (INIS)

    Wilson, George D.; Thibodeau, Bryan J.; Fortier, Laura E.; Pruetz, Barbara L.; Galoforo, Sandra; Baschnagel, Andrew M.; Chunta, John; Oliver Wong, Ching Yee; Yan, Di; Marples, Brian; Huang, Jiayi

    2014-01-01

    Purpose: To investigate whether radiation treatment influences the expression of glucose metabolism genes and compromises the potential use of 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) as a tool to monitor the early response of head and neck cancer xenografts to radiation therapy (RT). Methods and Materials: Low passage head and neck squamous cancer cells (UT14) were injected to the flanks of female nu/nu mice to generate xenografts. After tumors reached a size of 500 mm 3 they were treated with either sham RT or 15 Gy in 1 fraction. At different time points, days 3, 9, and 16 for controls and days 4, 7, 12, 21, 30, and 40 after irradiation, 2 to 3 mice were assessed with dynamic FDG-PET acquisition over 2 hours. Immediately after the FDG-PET the tumors were harvested for global gene expression analysis and immunohistochemical evaluation of GLUT1 and HK2. Different analytic parameters were used to process the dynamic PET data. Results: Radiation had no effect on key genes involved in FDG uptake and metabolism but did alter other genes in the HIF1α and glucose transport–related pathways. In contrast to the lack of effect on gene expression, changes in the protein expression patterns of the key genes GLUT1/SLC2A1 and HK2 were observed after radiation treatment. The changes in GLUT1 protein expression showed some correlation with dynamic FDG-PET parameters, such as the kinetic index. Conclusion: 18 F-fluorodeoxyglucose positron emission tomography changes after RT would seem to represent an altered metabolic state and not a direct effect on the key genes regulating FDG uptake and metabolism

  1. Activation of nuclear receptor NR5A2 increases Glut4 expression and glucose metabolism in muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Bolado-Carrancio, A. [Department of Molecular Biology, University of Cantabria, IDIVAL, Santander (Spain); Riancho, J.A. [Department of Internal Medicine, Hospital U.M. Valdecilla-IDIVAL, University of Cantabria, RETICEF, Santander (Spain); Sainz, J. [Institute of Biomedicine and Biotechnology of Cantabria (IBBTEC), CSIC-University of Cantabria, Santander (Spain); Rodríguez-Rey, J.C., E-mail: rodriguj@unican.es [Department of Molecular Biology, University of Cantabria, IDIVAL, Santander (Spain)

    2014-04-04

    Highlights: • NR5A2 expression in C2C12 is associated with myotube differentiation. • DLPC induces an increase in GLUT4 levels and glucose uptake in C2C12 myotubes. • In high glucose conditions the activation of NR5A2 inhibits fatty acids oxidation. - Abstract: NR5A2 is a nuclear receptor which regulates the expression of genes involved in cholesterol metabolism, pluripotency maintenance and cell differentiation. It has been recently shown that DLPC, a NR5A2 ligand, prevents liver steatosis and improves insulin sensitivity in mouse models of insulin resistance, an effect that has been associated with changes in glucose and fatty acids metabolism in liver. Because skeletal muscle is a major tissue in clearing glucose from blood, we studied the effect of the activation of NR5A2 on muscle metabolism by using cultures of C2C12, a mouse-derived cell line widely used as a model of skeletal muscle. Treatment of C2C12 with DLPC resulted in increased levels of expression of GLUT4 and also of several genes related to glycolysis and glycogen metabolism. These changes were accompanied by an increased glucose uptake. In addition, the activation of NR5A2 produced a reduction in the oxidation of fatty acids, an effect which disappeared in low-glucose conditions. Our results suggest that NR5A2, mostly by enhancing glucose uptake, switches muscle cells into a state of glucose preference. The increased use of glucose by muscle might constitute another mechanism by which NR5A2 improves blood glucose levels and restores insulin sensitivity.

  2. Xylose-induced dynamic effects on metabolism and gene expression in engineered Saccharomyces cerevisiae in anaerobic glucose-xylose cultures.

    Science.gov (United States)

    Alff-Tuomala, Susanne; Salusjärvi, Laura; Barth, Dorothee; Oja, Merja; Penttilä, Merja; Pitkänen, Juha-Pekka; Ruohonen, Laura; Jouhten, Paula

    2016-01-01

    Xylose is present with glucose in lignocellulosic streams available for valorisation to biochemicals. Saccharomyces cerevisiae has excellent characteristics as a host for the bioconversion, except that it strongly prefers glucose to xylose, and the co-consumption remains a challenge. Further, since xylose is not a natural substrate of S. cerevisiae, the regulatory response it induces in an engineered strain cannot be expected to have evolved for its utilisation. Xylose-induced effects on metabolism and gene expression during anaerobic growth of an engineered strain of S. cerevisiae on medium containing both glucose and xylose medium were quantified. The gene expression of S. cerevisiae with an XR-XDH pathway for xylose utilisation was analysed throughout the cultivation: at early cultivation times when mainly glucose was metabolised, at times when xylose was co-consumed in the presence of low glucose concentrations, and when glucose had been depleted and only xylose was being consumed. Cultivations on glucose as a sole carbon source were used as a control. Genome-scale dynamic flux balance analysis models were simulated to analyse the metabolic dynamics of S. cerevisiae. The simulations quantitatively estimated xylose-dependent flux dynamics and challenged the utilisation of the metabolic network. A relative increase in xylose utilisation was predicted to induce the bi-directionality of glycolytic flux and a redox challenge even at low glucose concentrations. Remarkably, xylose was observed to specifically delay the glucose-dependent repression of particular genes in mixed glucose-xylose cultures compared to glucose cultures. The delay occurred at a cultivation time when the metabolic flux activities were similar in the both cultures.

  3. Sucrose nonfermenting AMPK-related kinase (SNARK) mediates contraction-stimulated glucose transport in mouse skeletal muscle

    DEFF Research Database (Denmark)

    Koh, Ho-Jin; Toyoda, Taro; Fujii, Nobuharu

    2010-01-01

    The signaling mechanisms that mediate the important effects of contraction to increase glucose transport in skeletal muscle are not well understood, but are known to occur through an insulin-independent mechanism. Muscle-specific knockout of LKB1, an upstream kinase for AMPK and AMPK-related prot...

  4. An engineered cryptic Hxt11 sugar transporter facilitates glucose-xylose co-consumption in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Shin, Hyun Yong; Nijland, Jeroen G; de Waal, Paul P; de Jong, René M; Klaassen, Paul; Driessen, Arnold J M

    2015-01-01

    BACKGROUND: The yeast Saccharomyces cerevisiae is unable to ferment pentose sugars like d-xylose. Through the introduction of the respective metabolic pathway, S. cerevisiae is able to ferment xylose but first utilizes d-glucose before the d-xylose can be transported and metabolized. Low affinity

  5. Effect of vanadate on glucose transporter (GLUT4) intrinsic activity in skeletal muscle plasma membrane giant vesicles

    DEFF Research Database (Denmark)

    Kristiansen, S; Youn, J; Richter, Erik

    1996-01-01

    Maximally effective concentrations of vanadate (a phosphotyrosine phosphatase inhibitor) increase glucose transport in muscle less than maximal insulin stimulation. This might be due to vanadate-induced decreased intrinsic activity of GLUT4 accompanying GLUT4 translocation. Thus, the effect of va...

  6. Exercise-induced increase in glucose transport, GLUT-4, and VAMP-2 in plasma membrane from human muscle

    DEFF Research Database (Denmark)

    Kristiansen, S; Hargreaves, Mark; Richter, Erik

    1996-01-01

    A major effect of muscle contractions is an increase in sarcolemmal glucose transport. We have used a recently developed technique to produce sarcolemmal giant vesicles from human muscle biopsy samples obtained before and after exercise. Six men exercised for 10 min at 50% maximal O2 uptake (Vo2max...

  7. The Sodium-Glucose Co-Transporter 2 Inhibitor, Empagliflozin, Protects against Diabetic Cardiomyopathy by Inhibition of the Endoplasmic Reticulum Stress Pathway

    Directory of Open Access Journals (Sweden)

    Yang Zhou

    2017-05-01

    Full Text Available Background/Aims: This study aimed to determine whether or not the sodium-glucose co-transporter 2 inhibitor, empagliflozin (EMPA, can protect against diabetic cardiomyopathy (DCM and to elucidate the related mechanism. Methods: Rats were divided into the following four groups: a non-diabetic group; diabetic cardiomyopathy rats without EMPA treatment; and diabetic cardiomyopathy rats with EMPA treatment (low- and high-dose EMPA. Hemodynamic measurements were performed to evaluate left ventricular systolic and diastolic function. The histopathology of the heart was examined with hematoxylin-eosin staining. Expression of glucose-regulated protein (GRP78, enhancer-binding protein homologous protein (CHOP, and caspase-12 was detected by Western blot, and the mRNA levels of XBP1, ATF4, and TRAF2 were analysed by real-time PCR. Results: EMPA significantly decreased the blood glucose level when compared with vehicle. EMPA strongly improved cardiac function based on hemodynamic and histopathologic analyses. Moreover, EMPA can significantly down-regulate the expression of GRP78, CHOP, and caspase-12 (P < 0.01. Additionally, the mRNA levels of XBP1, ATF4, and TRAF2 were markedly decreased by administration of EMPA (P < 0.01. Conclusion: EMPA protects against DCM by inactivating the endoplasmic reticulum stress pathway.

  8. Enigma interacts with adaptor protein with PH and SH2 domains to control insulin-induced actin cytoskeleton remodeling and glucose transporter 4 translocation

    DEFF Research Database (Denmark)

    Barres, Romain; Grémeaux, Thierry; Gual, Philippe

    2006-01-01

    a critical role in actin cytoskeleton organization in fibroblastic cells. Because actin rearrangement is important for insulin-induced glucose transporter 4 (Glut 4) translocation, we studied the potential involvement of Enigma in insulin-induced glucose transport in 3T3-L1 adipocytes. Enigma m...

  9. Loss of arylformamidase with reduced thymidine kinase expression leads to impaired glucose tolerance

    Directory of Open Access Journals (Sweden)

    Alison J. Hugill

    2015-11-01

    Full Text Available Tryptophan metabolites have been linked in observational studies with type 2 diabetes, cognitive disorders, inflammation and immune system regulation. A rate-limiting enzyme in tryptophan conversion is arylformamidase (Afmid, and a double knockout of this gene and thymidine kinase (Tk has been reported to cause renal failure and abnormal immune system regulation. In order to further investigate possible links between abnormal tryptophan catabolism and diabetes and to examine the effect of single Afmid knockout, we have carried out metabolic phenotyping of an exon 2 Afmid gene knockout. These mice exhibit impaired glucose tolerance, although their insulin sensitivity is unchanged in comparison to wild-type animals. This phenotype results from a defect in glucose stimulated insulin secretion and these mice show reduced islet mass with age. No evidence of a renal phenotype was found, suggesting that this published phenotype resulted from loss of Tk expression in the double knockout. However, despite specifically removing only exon 2 of Afmid in our experiments we also observed some reduction of Tk expression, possibly due to a regulatory element in this region. In summary, our findings support a link between abnormal tryptophan metabolism and diabetes and highlight beta cell function for further mechanistic analysis.

  10. Family of Ricinus communis Monosaccharide Transporters and RcSTP1 in Promoting the Uptake of a Glucose-Fipronil Conjugate.

    Science.gov (United States)

    Mao, Gen-Lin; Yan, Yin; Chen, Yan; Wang, Bing-Feng; Xu, Fei-Fei; Zhang, Zhi-Xiang; Lin, Fei; Xu, Han-Hong

    2017-08-02

    Enhancing the systemic distribution of a bioactive compound by exploiting the vascular transport system of a plant presents a means of reducing both the volume and frequency of pesticide/fungicide application. The foliar uptake of the glucose-fipronil conjugate N-[3-cyano-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-[(trifluoromethyl)sulfinyl]-1H-pyrazol-5-yl]-1-(β-d-glucopyranosyl)-1H-1,2,3-triazole-4-methanamine (GTF) achieved in castor bean (Ricinus communis) and its transport via the phloem are known to be mediated by monosaccharide transporter(s) [MST(s)], although neither the identity of the key MST(s) involved nor the mechanistic basis of its movement have yet to be described. On the basis of homology with Arabidopsis thaliana sugar transporters, the castor bean genome was concluded to harbor 53 genes encoding a sugar transporter, falling into the eight previously defined subfamilies INT, PMT, VGT, STP, ERD6, pGlucT, TMT, and SUT. Transcriptional profiling identified the product of RcSTP1 as a candidate for mediating GTF uptake, because this gene was induced by exposure of the plant to GTF. When RcSTP1 was transiently expressed in onion epidermis cells, the site of RcSTP1 deposition was shown to be the plasma membrane. A functional analysis based on RcSTP1 expression in Xenopus laevis oocytes demonstrated that its product has a high affinity for GTF. The long-distance root-to-shoot transport of GTF was enhanced in a transgenic soybean chimera constitutively expressing RcSTP1.

  11. Andrographolide suppresses high glucose-induced fibronectin expression in mesangial cells via inhibiting the AP-1 pathway.

    Science.gov (United States)

    Lan, Tian; Wu, Teng; Gou, Hongju; Zhang, Qianqian; Li, Jiangchao; Qi, Cuiling; He, Xiaodong; Wu, Pingxiang; Wang, Lijing

    2013-11-01

    Mesangial cells (MCs) proliferation and accumulation of glomerular matrix proteins such as fibronectin (FN) are the early features of diabetic nephropathy, with MCs known to upregulate matrix protein synthesis in response to high glucose. Recently, it has been found that andrographolide has renoprotective effects on diabetic nephropathy. However, the molecular mechanism underlying these effects remains unclear. Cell viability and proliferation was evaluated by MTT. FN expression was examined by immunofluorescence and immunoblotting. Activator protein-1 (AP-1) activation was assessed by immunoblotting, luciferase reporter and electrophoretic mobility shift assays. Andrographolide significantly decreased high glucose-induced cell proliferation and FN expression in MCs. Exposure of MCs to high glucose markedly stimulated the expression of phosphorylated c-jun, whereas the stimulation was inhibited by andrographolide. Plasmid pAP-1-Luc luciferase reporter assay showed that andrographolide blocked high glucose-induced AP-1 transcriptional activity. EMSA assay demonstrated that increased AP-1 binding to an AP-1 binding site at -1,029 in the FN gene promoter upon high glucose stimulation, and the binding were disrupted by andrographolide treatment. These data indicate that andrographolide suppresses high glucose-induced FN expression by inhibiting AP-1-mediated pathway. © 2013 Wiley Periodicals, Inc.

  12. Glucose Transporter 1-Dependent Glycolysis Is Increased during Aging-Related Lung Fibrosis, and Phloretin Inhibits Lung Fibrosis.

    Science.gov (United States)

    Cho, Soo Jung; Moon, Jong-Seok; Lee, Chang-Min; Choi, Augustine M K; Stout-Delgado, Heather W

    2017-04-01

    Aging is associated with metabolic diseases such as type 2 diabetes mellitus, cardiovascular disease, cancer, and neurodegeneration. Aging contributes to common processes including metabolic dysfunction, DNA damage, and reactive oxygen species generation. Although glycolysis has been linked to cell growth and proliferation, the mechanisms by which the activation of glycolysis by aging regulates fibrogenesis in the lung remain unclear. The objective of this study was to determine if glucose transporter 1 (GLUT1)-induced glycolysis regulates age-dependent fibrogenesis of the lung. Mouse and human lung tissues were analyzed for GLUT1 and glycolytic markers using immunoblotting. Glycolytic function was measured using a Seahorse apparatus. To study the effect of GLUT1, genetic inhibition of GLUT1 was performed by short hairpin RNA transduction, and phloretin was used for pharmacologic inhibition of GLUT1. GLUT1-dependent glycolysis is activated in aged lung. Genetic and pharmacologic inhibition of GLUT1 suppressed the protein expression of α-smooth muscle actin, a key cytoskeletal component of activated fibroblasts, in mouse primary lung fibroblast cells. Moreover, we demonstrated that the activation of AMP-activated protein kinase, which is regulated by GLUT1-dependent glycolysis, represents a critical metabolic pathway for fibroblast activation. Furthermore, we demonstrated that phloretin, a potent inhibitor of GLUT1, significantly inhibited bleomycin-induced lung fibrosis in vivo. These results suggest that GLUT1-dependent glycolysis regulates fibrogenesis in aged lung and that inhibition of GLUT1 provides a potential target of therapy of age-related lung fibrosis.

  13. Neurotrophin and Trk expression by cells of the human lamina cribrosa following oxygen-glucose deprivation

    Directory of Open Access Journals (Sweden)

    Clark Abbot F

    2004-12-01

    Full Text Available Abstract Background Ischemia within the optic nerve head (ONH may contribute to retinal ganglion cell (RGC loss in primary open angle glaucoma (POAG. Ischemia has been reported to increase neurotrophin and high affinity Trk receptor expression by CNS neurons and glial cells. We have previously demonstrated neurotrophin and Trk expression within the lamina cribrosa (LC region of the ONH. To determine if ischemia alters neurotrophin and Trk protein expression in cells from the human LC, cultured LC cells and ONH astrocytes were exposed to 48 hours of oxygen-glucose deprivation (OGD. Also cells were exposed to 48 hours of OGD followed by 24 hours of recovery in normal growth conditions. Cell number, neurotrophin and Trk receptor protein expression, neurotrophin secretion, and Trk receptor activation were examined. Results Cell number was estimated using an assay for cell metabolism following 24, 48 and 72 hours of OGD. A statistically significant decrease in LC and ONH astrocyte cell number did not occur until 72 hours of OGD, therefore cellular protein and conditioned media were collected at 48 hours OGD. Protein expression of NGF, BDNF and NT-3 by LC cells and ONH astrocytes increased following OGD, as did NGF secretion. Recovery from OGD increased BDNF protein expression in LC cells. In ONH astrocytes, recovery from OGD increased NGF protein expression, and decreased BDNF secretion. Trk A expression and activation in LC cells was increased following OGD while expression and activation of all other Trk receptors was decreased. A similar increase in Trk A expression and activation was observed in ONH astrocytes following recovery from OGD. Conclusions In vitro conditions that mimic ischemia increase the expression and secretion of neurotrophins by cells from the ONH. Increased Trk A expression and activation in LC cells following OGD and in ONH astrocytes following recovery from OGD suggest autocrine/paracrine neurotrophin signaling could be a

  14. The metabolic trinity, glucose-glycogen-lactate, links astrocytes and neurons in brain energetics, signaling, memory, and gene expression.

    Science.gov (United States)

    Dienel, Gerald A

    2017-01-10

    Glucose, glycogen, and lactate are traditionally identified with brain energetics, ATP turnover, and pathophysiology. However, recent studies extend their roles to include involvement in astrocytic signaling, memory consolidation, and gene expression. Emerging roles for these brain fuels and a readily-diffusible by-product are linked to differential fluxes in glycolytic and oxidative pathways, astrocytic glycogen dynamics, redox shifts, neuron-astrocyte interactions, and regulation of astrocytic activities by noradrenaline released from the locus coeruleus. Disproportionate utilization of carbohydrate compared with oxygen during brain activation is influenced by catecholamines, but its physiological basis is not understood and its magnitude may be affected by technical aspects of metabolite assays. Memory consolidation and gene expression are impaired by glycogenolysis blockade, and prevention of these deficits by injection of abnormally-high concentrations of lactate was interpreted as a requirement for astrocyte-to-neuron lactate shuttling in memory and gene expression. However, lactate transport was not measured and evidence for presumed shuttling is not compelling. In fact, high levels of lactate used to preserve memory consolidation and induce gene expression are sufficient to shut down neuronal firing via the HCAR1 receptor. In contrast, low lactate levels activate a receptor in locus coeruleus that stimulates noradrenaline release that may activate astrocytes throughout brain. Physiological relevance of exogenous concentrations of lactate used to mimic and evaluate metabolic, molecular, and behavioral effects of lactate requires close correspondence with the normal lactate levels, the biochemical and cellular sources and sinks, and specificity of lactate delivery to target cells. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  15. Biological and Clinical Study of 6-Deoxy-6-Iodo-D-Glucose: a iodinated tracer of glucose transport and of insulin-resistance in human

    International Nuclear Information System (INIS)

    Barone-Rochette, Gilles

    2013-01-01

    Insulin resistance (IR), characterized by a depressed cellular sensitivity to insulin in insulin-sensitive organs, is a central feature to obesity, the metabolic syndrome, and diabetes mellitus and leads to increase cardiovascular diseases, particularly heart failure. All these events are today serious public health problems. But actually, there is no simple tool to measure insulin resistance. The gold standard technique remains the hyperinsulinemic euglycemic clamp. However, the complexity and length of this technique render it unsuitable for routine clinical use. Many methods or index have been proposed to assess insulin resistance in human, but none have shown enough relevance to be used in clinical use. The U1039 INSERM unit previously has validated a new tracer of glucose transport, radiolabelled with 123 iodine and has developed a fast and simple imaging protocol with a small animal gamma camera, which allows the obtaining of an IR index for each organ, showing more discriminating for the heart. The project of my thesis was the human transfer of this measurement technique, perfectly validated in animal. The first part of this thesis evaluated to tolerance, in vivo kinetics, distribution and dosimetry of novel tracer of glucose transport, the [ 123 I]-6DIG. The safeties of new tracer and measurement technique were adequate. There were no adverse effects with excellent tolerance of the whole protocol. 6DIG eliminating was fast, primarily in the urine and complete within 72 h. The effective whole-body absorbed dose for a complete scan with injection of 92.5 * 2 MBq was between 3 to 4 mSv. The second part of this thesis evaluated in human feasibility and reproducibility of the measurement technique validated in animal. The third part showed techniques used to allow human transfer of this method. The study protocol was applied on 12 subjects (healthy volunteers (n=6) and type 2 diabetic patients (n=6)). With a method adapted to measure in humans, we determined an

  16. NFAT2 mediates high glucose-induced glomerular podocyte apoptosis through increased Bax expression

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ruizhao, E-mail: liruizhao1979@126.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Zhang, Li, E-mail: Zhanglichangde@163.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Southern Medical University, Guangzhou, Guangdong (China); Shi, Wei, E-mail: shiwei.gd@139.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Zhang, Bin, E-mail: zhangbinyes@yahoo.com.cn [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Liang, Xinling, E-mail: xinlingliang@yahoo.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Liu, Shuangxin, E-mail: mplsxi@yahoo.com.cn [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Wang, Wenjian, E-mail: wwjph@yahoo.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China)

    2013-04-15

    Background: Hyperglycemia promotes podocyte apoptosis and plays a key role in the pathogenesis of diabetic nephropathy. However, the mechanisms that mediate hyperglycemia-induced podocyte apoptosis is still far from being fully understood. Recent studies reported that high glucose activate nuclear factor of activated T cells (NFAT) in vascular smooth muscle or pancreatic β-cells. Here, we sought to determine if hyperglycemia activates NFAT2 in cultured podocyte and whether this leads to podocyte apoptosis. Meanwhile, we also further explore the mechanisms of NFAT2 activation and NFAT2 mediates high glucose-induced podocyte apoptosis. Methods: Immortalized mouse podocytes were cultured in media containing normal glucose (NG), or high glucose (HG) or HG plus cyclosporine A (a pharmacological inhibitor of calcinerin) or 11R-VIVIT (a special inhibitor of NFAT2). The activation of NFAT2 in podocytes was detected by western blotting and immunofluorescence assay. The role of NFAT2 in hyperglycemia-induced podocyte apoptosis was further evaluated by observing the inhibition of NFAT2 activation by 11R-VIVIT using flow cytometer. Intracellular Ca{sup 2+} was monitored in HG-treated podcocytes using Fluo-3/AM. The mRNA and protein expression of apoptosis gene Bax were measured by real time-qPCR and western blotting. Results: HG stimulation activated NFAT2 in a time- and dose-dependent manner in cultured podocytes. Pretreatment with cyclosporine A (500 nM) or 11R-VIVIT (100 nM) completely blocked NFAT2 nuclear accumulation. Meanwhile, the apoptosis effects induced by HG were also abrogated by concomitant treatment with 11R-VIVIT in cultured podocytes. We further found that HG also increased [Ca{sup 2+}]i, leading to activation of calcineurin, and subsequent increased nuclear accumulation of NFAT2 and Bax expression in cultured podocytes. Conclusion: Our results identify a new finding that HG-induced podocyte apoptosis is mediated by calcineurin/NFAT2/Bax signaling pathway

  17. Riluzole increases the rate of glucose transport in L6 myotubes and NSC-34 motor neuron-like cells via AMPK pathway activation.

    Science.gov (United States)

    Daniel, Bareket; Green, Omer; Viskind, Olga; Gruzman, Arie

    2013-09-01

    Riluzole is the only approved ALS drug. Riluzole influences several cellular pathways, but its exact mechanism of action remains unclear. Our goal was to study the drug's influence on the glucose transport rate in two ALS relevant cell types, neurons and myotubes. Stably transfected wild-type or mutant G93A human SOD1 NSC-34 motor neuron-like cells and rat L6 myotubes were exposed to riluzole. The rate of glucose uptake, translocation of glucose transporters to the cell's plasma membrane and the main glucose transport regulatory proteins' phosphorylation levels were measured. We found that riluzole increases the glucose transport rate and up-regulates the translocation of glucose transporters to plasma membrane in both types of cells. Riluzole leads to AMPK phosphorylation and to the phosphorylation of its downstream target, AS-160. In conclusion, increasing the glucose transport rate in ALS affected cells might be one of the mechanisms of riluzole's therapeutic effect. These findings can be used to rationally design and synthesize novel anti-ALS drugs that modulate glucose transport in neurons and skeletal muscles.

  18. GLUCOSE DEPRIVATION AFFECTS THE EXPRESSION OF LONP1 AND CATHEPSINS IN IRE1 KNOCKDOWN U87 GLIOMA CELLS

    Directory of Open Access Journals (Sweden)

    O. H. Minchenko

    2016-12-01

    Full Text Available To study the effect of glucose deprivation on the expression of genes encoding for LONP1/PRSS15 and cathepsins in U87 glioma cells in relation to inhibition of inositol requiring enzyme-1 (IRE1 was the aim of the research. It was shown that glucose deprivation up-regulated the expression of CTSA, CTSB, CTSD, CTSK, CTSL, CTSO, and LONP1 genes and did not change the expression of CTSC, CTSF, and CTSS genes in control glioma cells (transfected by empty vector. Inhibition of ІRE1 signaling enzyme function in U87 glioma cells modified effect of glucose deprivation on the expression of most studied genes: removed the effect of glucose deprivation on CTSA and CTSO genes, introduces on CTSC and CTSS genes, reduced – on CTSK gene, and enhanced – on CTSL gene. Therefore, glucose deprivation affect the expression level of most studied genes in relation to the functional activity of IRE1 enzyme, a central mediator of endoplasmic reticulum stress, which control cell proliferation and tumor growth.

  19. Effects of IL-10 and glucose on expression of OPG and RANKL in human periodontal ligament fibroblasts

    Directory of Open Access Journals (Sweden)

    L. Zhang

    2016-01-01

    Full Text Available The effects of interleukin-10 (IL-10 and glucose on mRNA and protein expression of osteoprotegerin (OPG, and its ligand, receptor activator of nuclear factor-κB ligand (RANKL, were investigated in human periodontal ligament fibroblasts (HPDLFs. Primary HPDLFs were treated with different concentrations of IL-10 (0, 1, 10, 25, 50, and 100 ng/mL or glucose (0, 5.5, 10, 20, 30, and 40 mmol/L. Changes in mRNA and protein expression were examined using the reverse-transcription polymerase chain reaction (RT-PCR and Western blot analysis, respectively. After IL-10 treatment, mRNA and protein levels of OPG were increased, while mRNA and protein levels of RANKL were decreased (P<0.05, both in a concentration-dependent manner. Glucose stimulation had the opposite concentration-dependent effect to that of IL-10 on OPG and RANKL expression. IL-10 upregulated OPG expression and downregulated RANKL expression, whereas high glucose upregulated RANKL and downregulated OPG in HDPLFs. Abnormal levels of IL-10 and glucose may contribute to the pathogenesis of periodontal disease.

  20. Insulin Resistance in Nondiabetic Peritoneal Dialysis Patients: Associations with Body Composition, Peritoneal Transport, and Peritoneal Glucose Absorption.

    Science.gov (United States)

    Bernardo, Ana Paula; Oliveira, Jose C; Santos, Olivia; Carvalho, Maria J; Cabrita, Antonio; Rodrigues, Anabela

    2015-12-07

    Insulin resistance has been associated with cardiovascular disease in peritoneal dialysis patients. Few studies have addressed the impact of fast transport status or dialysis prescription on insulin resistance. The aim of this study was to test whether insulin resistance is associated with obesity parameters, peritoneal transport rate, and glucose absorption. Insulin resistance was evaluated with homeostasis model assessment method (HOMA-IR), additionally corrected by adiponectin (HOMA-AD). Enrolled patients were prevalent nondiabetics attending at Santo António Hospital Peritoneal Dialysis Unit, who were free of hospitalization or infectious events in the previous 3 months (51 patients aged 50.4 ± 15.9 years, 59% women). Leptin, adiponectin, insulin-like growth factor-binding protein 1 (IGFBP-1), and daily glucose absorption were also measured. Lean tissue index, fat tissue index (FTI), and relative fat mass (rel.FM) were assessed using multifrequency bioimpedance. Patients were categorized according to dialysate to plasma creatinine ratio at 4 hours, 3.86% peritoneal equilibration test, and obesity parameters. Obesity was present in 49% of patients according to rel.FM. HOMA-IR correlated better with FTI than with body mass index. Significant correlations were found in obese, but not in nonobese patients, between HOMA-IR and leptin, leptin/adiponectin ratio (LAR), and IGFBP-1. HOMA-IR correlated with HOMA-AD, but did not correlate with glucose absorption or transport rate. There were no significant differences in insulin resistance indices, glucose absorption, and body composition parameters between fast and nonfast transporters. A total of 18 patients (35.3%) who had insulin resistance presented with higher LAR and rel.FM (7.3 [12.3, interquartile range] versus 0.7 [1.4, interquartile range], Pinsulin resistance. FTI and LAR were independent correlates of HOMA-IR in multivariate analysis adjusted for glucose absorption and small-solute transport (r=0

  1. Resveratrol Prevents Retinal Dysfunction by Regulating Glutamate Transporters, Glutamine Synthetase Expression and Activity in Diabetic Retina.

    Science.gov (United States)

    Zeng, Kaihong; Yang, Na; Wang, Duozi; Li, Suping; Ming, Jian; Wang, Jing; Yu, Xuemei; Song, Yi; Zhou, Xue; Yang, Yongtao

    2016-05-01

    This study investigated the effects of resveratrol (RSV) on retinal functions, glutamate transporters (GLAST) and glutamine synthetase (GS) expression in diabetic rats retina, and on glutamate uptake, GS activity, GLAST and GS expression in high glucose-cultured Müller cells. The electroretinogram was used to evaluate retinal functions. Müller cells cultures were prepared from 5- to 7-day-old Sprague-Dawley rats. The expression of GLAST and GS was examined by qRT-PCR, ELISA and western-blotting. Glutamate uptake was measured as (3)H-glutamate contents of the lysates. GS activity was assessed by a spectrophotometric assay. 1- to 7-month RSV administrations (5 and 10 mg/kg/day) significantly alleviated hyperglycemia and weight loss in diabetic rats. RSV administrations also significantly attenuated diabetes-induced decreases in amplitude of a-wave in rod response, decreases in amplitude of a-, and b-wave in cone and rod response and decreases in amplitude of OP2 in oscillatory potentials. 1- to 7-month RSV treatments also significantly inhibited diabetes-induced delay in OP2 implicit times in scotopic 3.0 OPS test. The down-regulated mRNA and protein expression of GLAST and GS in diabetic rats retina was prevented by RSV administrations. In high glucose-treated cultures, Müller cells' glutamate uptake, GS activity, GLAST and GS expression were decreased significantly compared with normal control cultures. RSV (10, 20, and 30 mmol/l) significantly inhibited the HG-induced decreases in glutamate uptake, GS activity, GLAST and GS expression (at least P < 0.05). These beneficial results suggest that RSV may be considered as a therapeutic option to prevent from diabetic retinopathy.

  2. High glucose induces apoptosis via upregulation of Bim expression in proximal tubule epithelial cells.

    Science.gov (United States)

    Zhang, Xiao-Qian; Dong, Jian-Jun; Cai, Tian; Shen, Xue; Zhou, Xiao-Jun; Liao, Lin

    2017-04-11

    Diabetic nephropathy is the primary cause of end-stage renal disease. Apoptosis of tubule epithelial cells is a major feature of diabetic nephropathy. The mechanisms of high glucose (HG) induced apoptosis are not fully understood. Here we demonstrated that, HG induced apoptosis via upregulating the expression of proapoptotic Bcl-2 homology domain 3 (BH3)-only protein Bim protein, but not bring a significant change in the baseline level of autophagy in HK2 cells. The increase of Bim expression was caused by the ugregulation of transcription factors, FOXO1 and FOXO3a. Bim expression initiates BAX/BAK-mediated mitochondria-dependent apoptosis. Silence of Bim by siRNA in HK2 cells prevented HG-induced apoptosis and also sensitized HK2 cells to autophagy during HG treatment. The autophagy inhibitor 3-MA increased the injury in Bim knockdown HK2 cells by retriggering apoptosis. The above results suggest a Bim-independent apoptosis pathway in HK2 cells, which normally could be inhibited by autophagy. Overall, our results indicate that HG induces apoptosis via up-regulation of Bim expression in proximal tubule epithelial cells.

  3. The Role of PXR Genotype and Transporter Expression in the Placental Transport of Lopinavir in Mice

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    Sarabjit S. Gahir

    2017-10-01

    Full Text Available Lopinavir (LPV, an antiretroviral protease inhibitor frequently prescribed in HIV-positive pregnancies, is a substrate of Abcb1 and Abcc2. As differences in placental expression of these transporters were seen in Pregnane X Receptor (PXR −/− mice, we examined the impact of placental transporter expression and fetal PXR genotype on the fetal accumulation of LPV. PXR +/− dams bearing PXR +/+, PXR +/−, and PXR −/− fetuses were generated by mating PXR +/− female mice with PXR +/− males. On gestational day 17, dams were administered 10 mg/kg LPV (i.v. and sacrificed 30 min post injection. Concentrations of LPV in maternal plasma and fetal tissue were measured by LC-MS/MS, and transporter expression was determined by quantitative RT-PCR. As compared to the PXR +/+ fetal units, placental expression of Abcb1a, Abcc2, and Abcg2 mRNA were two- to three-fold higher in PXR −/− fetuses (p < 0.05. Two-fold higher fetal:maternal LPV concentration ratios were also seen in the PXR +/+ as compared to the PXR −/− fetuses (p < 0.05, and this significantly correlated to the placental expression of Abcb1a (r = 0.495; p < 0.005. Individual differences in the expression of placental transporters due to genetic or environmental factors can impact fetal exposure to their substrates.

  4. The effects of altitude training on the AMPK-related glucose transport pathway in the red skeletal muscle of both lean and obese Zucker rats.

    Science.gov (United States)

    Chen, Yu-Ching; Lee, Shin-Da; Kuo, Cha-Hua; Ho, Low-Tone

    2011-01-01

    The skeletal muscle AMP-activated protein kinase (AMPK)-related glucose transport pathway is involved in glucose homeostasis. In this study, we examined whether obese control Zucker rats had abnormal expression of proteins in the LKB1-AMPK-AS160-GLUT4 pathway in red gastrocnemius muscle compared to that in lean (normal) control Zucker rats. We also compared the chronic training effects of exercise, hypoxia, and altitude training on this pathway in lean and obese rats. At sea level, lean and obese rats were divided into 4 groups for 6 weeks training as follows: 1) control; 2) exercise (progressive daily swimming-exercise training with comparable exercise signals between the two groups); 3) hypoxia (8 hours of daily 14% O2 exposure); and 4) exercise plus hypoxia (also called altitude training). Seven animals were used for each group. The obese rats in the control group had higher body weights, elevated fasting insulin and glucose levels, and higher baseline levels of muscle AMPK and AS160 phosphorylation compared with those of lean control rats. For obese Zucker rats in the exercise or hypoxia groups, the muscle AMPK phosphorylation level was significantly decreased compared with that of the control group. For obese Zucker rats in the altitude training group, the levels of AMPK, AS160 phosphorylation, fasting insulin, and fasting glucose were decreased concomitant with an approximate 50% increase in the muscle GLUT4 protein level compared with those of the control group. In lean rats, the altitude training efficiently lowered fasting glucose and insulin levels and increased muscle AMPK and AS160 phosphorylation as well as GLUT4 protein levels. Our results provide evidence that long-term altitude training may be a potentially effective nonpharmacological strategy for treating and preventing insulin resistance based on its effects on the skeletal muscle AMPK-AS160-GLUT4 pathway.

  5. Sodium glucose transporter-2 inhibition has no renoprotective effects on non-diabetic chronic kidney disease.

    Science.gov (United States)

    Ma, Qiuyue; Steiger, Stefanie; Anders, Hans-Joachim

    2017-04-01

    Sodium glucose transporter (SGLT)-2 inhibition has renoprotective effects in diabetic kidney disease. Whether similar effects can be achieved also in non-diabetic kidney disease is speculative. Chronic kidney disease was induced in C57BL/6N mice by feeding an oxalate-rich diet for 14 days, known to induce nephrocalcinosis-related tubular atrophy and interstitial fibrosis without directly affecting the glomerular compartment. Empagliflozin treatment started from day 0 of oxalate feeding had no effect on the decline of glomerular filtration rate, crystal deposition, blood urea nitrogen or serum creatinine levels on day 7 and 14. Tissue morphometry of tubular injury and kidney mRNA levels of kidney injury molecule-1 or tissue inhibitor of metalloproteinase-2 were comparable between empagliflozin- and vehicle-treated mice with oxalate nephropathy on day 7 and 14. Similarly, empagliflozin did not affect markers of interstitial fibrosis, including silver, alpha smooth muscle actin ( α SMA) and collagen 1 staining, and mRNA levels of fibronectin-1, collagen 1 α 1, fibroblast-specific protein-1, and transforming growth factor (TGF)- β 2 on day 7 and 14. Thus, the specific renoprotective mechanisms-of-action of SGLT2 inhibition in diabetic kidney disease do not apply to chronic oxalosis, a non-diabetic form of chronic kidney disease. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

  6. Phenotypic spectrum of glucose transporter type 1 deficiency syndrome (Glut1 DS).

    Science.gov (United States)

    Pearson, Toni S; Akman, Cigdem; Hinton, Veronica J; Engelstad, Kristin; De Vivo, Darryl C

    2013-04-01

    Glut1 deficiency syndrome (Glut1 DS) was originally described in 1991 as a developmental encephalopathy characterized by infantile onset refractory epilepsy, cognitive impairment, and mixed motor abnormalities including spasticity, ataxia, and dystonia. The clinical condition is caused by impaired glucose transport across the blood brain barrier. The past 5 years have seen a dramatic expansion in the range of clinical syndromes that are recognized to occur with Glut1 DS. In particular, there has been greater recognition of milder phenotypes. Absence epilepsy and other idiopathic generalized epilepsy syndromes may occur with seizure onset in childhood or adulthood. A number of patients present predominantly with movement disorders, sometimes without any accompanying seizures. In particular, paroxysmal exertional dyskinesia is now a well-documented clinical feature that occurs in individuals with Glut1 DS. A clue to the diagnosis in patients with paroxysmal symptoms may be the triggering of episodes during fasting or exercise. Intellectual impairment may range from severe to very mild. Awareness of the broad range of potential clinical phenotypes associated with Glut1 DS will facilitate earlier diagnosis of this treatable neurologic condition. The ketogenic diet is the mainstay of treatment and nourishes the starving symptomatic brain during development.

  7. Genetic changes during a laboratory adaptive evolution process that allowed fast growth in glucose to an Escherichia coli strain lacking the major glucose transport system

    Directory of Open Access Journals (Sweden)

    Aguilar César

    2012-08-01

    Full Text Available Abstract Background Escherichia coli strains lacking the phosphoenolpyruvate: carbohydrate phosphotransferase system (PTS, which is the major bacterial component involved in glucose transport and its phosphorylation, accumulate high amounts of phosphoenolpyruvate that can be diverted to the synthesis of commercially relevant products. However, these strains grow slowly in glucose as sole carbon source due to its inefficient transport and metabolism. Strain PB12, with 400% increased growth rate, was isolated after a 120 hours adaptive laboratory evolution process for the selection of faster growing derivatives in glucose. Analysis of the genetic changes that occurred in the PB12 strain that lacks PTS will allow a better understanding of the basis of its growth adaptation and, therefore, in the design of improved metabolic engineering strategies for enhancing carbon diversion into the aromatic pathways. Results Whole genome analyses using two different sequencing methodologies: the Roche NimbleGen Inc. comparative genome sequencing technique, and high throughput sequencing with Illumina Inc. GAIIx, allowed the identification of the genetic changes that occurred in the PB12 strain. Both methods detected 23 non-synonymous and 22 synonymous point mutations. Several non-synonymous mutations mapped in regulatory genes (arcB, barA, rpoD, rna and in other putative regulatory loci (yjjU, rssA and ypdA. In addition, a chromosomal deletion of 10,328 bp was detected that removed 12 genes, among them, the rppH, mutH and galR genes. Characterization of some of these mutated and deleted genes with their functions and possible functions, are presented. Conclusions The deletion of the contiguous rppH, mutH and galR genes that occurred simultaneously, is apparently the main reason for the faster growth of the evolved PB12 strain. In support of this interpretation is the fact that inactivation of the rppH gene in the parental PB11 strain substantially increased

  8. The SLC2A14 gene, encoding the novel glucose/dehydroascorbate transporter GLUT14, is associated with inflammatory bowel disease.

    Science.gov (United States)

    Amir Shaghaghi, Mandana; Zhouyao, Haonan; Tu, Hongbin; El-Gabalawy, Hani; Crow, Gary H; Levine, Mark; Bernstein, Charles N; Eck, Peter

    2017-12-01

    Background: Variations in intestinal antioxidant membrane transporters are implicated in the initiation and progression of inflammatory bowel disease (IBD). Facilitated glucose transporter member 14 (GLUT14), encoded by the solute carrier family 2 member 14 ( SLC2A14 ) gene, is a putative transporter for dehydroascorbic acid and glucose. Although information on the gene is limited, shorter and longer GLUT14 isoforms have been identified. We hypothesized that GLUT14 mediates glucose and dehydroascorbic acid uptake. If this function could be validated, then genetic variations may associate with IBD. Objective: This study aimed to determine the substrate(s) for the GLUT14 protein and interrogated genetic associations of SLC2A14 with IBD. Design: The uptake of radiolabeled substrates into Xenopus laevis oocytes expressing the 2 GLUT14 isoforms was assessed. Examination of gene-targeted genetic association in the Manitoba Inflammatory Bowel Disease Cohort Study was conducted through the genotyping of single nucleotide polymorphisms (SNPs) representing linkage blocks of the SLC2A14 gene. Results: Both GLUT14 isoforms mediated the uptake of dehydroascorbic acid and glucose into X. laevis oocytes. Three alleles in the SLC2A14 gene associated independently with IBD. The odds of having ulcerative colitis (UC) or Crohn disease (CD) were elevated in carriers of the SLC2A14 SNP rs2889504-T allele (OR: 3.60; 95% CI: 1.95, 6.64 and OR: 4.68; 95% CI: 2.78, 8.50, respectively). Similarly, the SNP rs10846086-G allele was associated with an increased risk of both UC and CD (OR: 2.91; 95% CI: 1.49, 5.68 and OR: 3.00; 95% CI: 1.55, 5.78, respectively). Moreover, the SNP rs12815313-T allele associated with increased susceptibility to CD and UC (OR: 2.12; 95% CI: 1.33, 3.36 and OR: 1.61; 95% CI: 1.01, 2.57, respectively). Conclusion: These findings strengthen the hypothesis that genetically determined local dysregulation of dietary vitamin C or antioxidants transport contributes to IBD

  9. Do Glut1 (glucose transporter type 1) defects exist in epilepsy patients responding to a ketogenic diet?

    Science.gov (United States)

    Becker, Felicitas; Schubert, Julian; Weckhuysen, Sarah; Suls, Arvid; Grüninger, Steffen; Korn-Merker, Elisabeth; Hofmann-Peters, Anne; Sperner, Jürgen; Cross, Helen; Hallmann, Kerstin; Elger, Christian E; Kunz, Wolfram S; Madeleyen, René; Lerche, Holger; Weber, Yvonne G

    2015-08-01

    In the recent years, several neurological syndromes related to defects of the glucose transporter type 1 (Glut1) have been descried. They include the glucose transporter deficiency syndrome (Glut1-DS) as the most severe form, the paroxysmal exertion-induced dyskinesia (PED), a form of spastic paraparesis (CSE) as well as the childhood (CAE) and the early-onset absence epilepsy (EOAE). Glut1, encoded by the gene SLC2A1, is the most relevant glucose transporter in the brain. All Glut1 syndromes respond well to a ketogenic diet (KD) and most of the patients show a rapid seizure control. Ketogenic Diet developed to an established treatment for other forms of pharmaco-resistant epilepsies. Since we were interested in the question if those patients might have an underlying Glut1 defect, we sequenced SLC2A1 in a cohort of 28 patients with different forms of pharmaco-resistant epilepsies responding well to a KD. Unfortunately, we could not detect any mutations in SLC2A1. The exact action mechanisms of KD in pharmaco-resistant epilepsy are not well understood, but bypassing the Glut1 transporter seems not to play an important role. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. D-glucose transport and glycolytic enzyme activities in erythrocytes of dogs, pigs, cats, horses, cattle and sheep.

    Science.gov (United States)

    Arai, T; Washizu, T; Sagara, M; Sako, T; Nigi, H; Matsumoto, H; Sasaki, M; Tomoda, I

    1995-03-01

    The activities of D-glucose transport (D-GT) and the glycolytic enzymes hexokinase (HK) and pyruvate kinase (PK), were measured in the erythrocytes of dogs, pigs, cats, horses, cattle and sheep. The erythrocytes of dogs had the highest activities of D-GT, HK and PK, significantly higher than the activities in the erythrocytes of the herbivores. The activities of D-GT and HK in cat erythrocytes were significantly lower than in those of dogs. The differences between the activities of D-GT in the erythrocytes of the different species followed the differences in activities of HK but not those in the activities of PK or in the blood glucose concentrations. It is considered that the activity of HK provides a convenient measurement of the relative rates of glucose oxidation in erythrocytes.

  11. Inhibition of sodium glucose cotransporter-I expressed in Xenopus laevis oocytes by 4-acetoxyscirpendiol from Cordyceps takaomantana (anamorph = Paecilomyces tenuipes).

    Science.gov (United States)

    Yoo, Ocki; Lee, Dong-Hee

    2006-02-01

    Cordyceps contains many health-promoting constituents. Recent studies revealed that the fruiting body of cordyceps significantly alleviates hyperglycemia which usually accompanies diabetes mellitus. The mechanism of the anti-hyperglycemic effect by cordyceps, however, is not fully understood. In this study, methanolic extracts were prepared from fruiting bodies of Paecilomyces tenuipes, and 4-beta acetoxyscirpendiol (ASD) was eventually purified from the extracts. The Na+/ glucose transporter-1 (SGLT-1) was expressed in Xenopus oocytes, and the effect of ASD on it was analyzed using voltage clamp and 2-deoxy-D-glucose (2-DOG) uptake studies. Fluorescence microscopy was performed to monitor the effect of ASD on glucose uptake using HEK293 cells expressing recombinant SGLT-1. ASD inhibited SGLT-1 activity, and its two derivatives (2-acetoxyscirpenol and 15-acetoxyscirpendiol), were also effective; 15-acetoxyscirepenol was as inhibitory as ASD while diacetoxyscirpenol had less effect. Thus, the ASD in P. tenuipes may play an important role in lowering blood sugar in the circulatory system along with its derivatives as specific inhibitors of SGLT-1.

  12. Differential expression of tuberoinfundibular peptide 38 and glucose-6-phosphatase in tilapia.

    Science.gov (United States)

    Shoemaker, Justin M; Riley, Larry G; Hirano, Tetsuya; Grau, E Gordon; Rubin, David A

    2006-04-01

    A new parathyroid hormone (PTH)-like endocrine system has been identified in mammals and fishes consisting of the PTH type-2 receptor (PTH2R) and tuberoinfundibular peptide 39 (TIP39). Although the mammalian PTH2R-TIP39 system is involved in nociception and pituitary regulation, the function(s) of this system in fishes is undetermined. Using degenerate primers based on conserved zebrafish and fugu TIP39 nucleotide sequences, 3'-RACE reactions isolated the coding region of a putative TIP38 cDNA in the Nile tilapia (Oreochromis niloticus). Tilapia-specific primers were subsequently used in 5'-RACE reactions to isolate the remaining portion of the transcript. The cDNA encoding O. niloticus TIP (OnTIP38) was determined to yield a 38 amino acid secreted hormone. A second tilapia TIP38 cDNA was isolated from the euryhaline Mozambique tilapia (OmTIP38). Except for the 39th residue, both tilapia cDNA sequences showed significant identity to human, bovine, murine, fugu, and zebrafish TIP39. To determine the tissue-specific expression of OnTIP38 and OmTIP38, real-time quantitative RT-PCR (rQRT-PCR) was performed on skin, gill, kidney, testis, heart, and brain. In freshwater (FW)-acclimated Nile tilapia, OnTIP38 showed highest levels of expression in kidney and lowest levels in skin and gill. In Mozambique tilapia tissues, expression of OmTIP38 and G6Pase (glucose-6 phosphatase) were higher in salt water (SW)-acclimated fish than in FW-acclimated fish. G6Pase expression, and not OmTIP38, showed significant differences among various tissues in FW- and SW-acclimated fish. Results of the present study clearly indicate that the TIP38/39-PTH2R system shows considerable conservation in sequence identity and tissue-specific expression in mammals and fishes.

  13. Identification of network topological units coordinating the global expression response to glucose in Bacillus subtilis and its comparison to Escherichia coli

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    Gutiérrez-Ríos Rosa

    2009-08-01

    Full Text Available Abstract Background Glucose is the preferred carbon and energy source for Bacillus subtilis and Escherichia coli. A complex regulatory network coordinates gene expression, transport and enzymatic activities, in response to the presence of this sugar. We present a comparison of the cellular response to glucose in these two model organisms, using an approach combining global transcriptome and regulatory network analyses. Results Transcriptome data from strains grown in Luria-Bertani medium (LB or LB+glucose (LB+G were analyzed, in order to identify differentially transcribed genes in B. subtilis. We detected 503 genes in B. subtilis that change their relative transcript levels in the presence of glucose. A similar previous study identified 380 genes in E. coli, which respond to glucose. Catabolic repression was detected in the case of transport and metabolic interconversion activities for both bacteria in LB+G. We detected an increased capacity for de novo synthesis of nucleotides, amino acids and proteins. A comparison between orthologous genes revealed that global regulatory functions such as transcription, translation, replication and genes relating to the central carbon metabolism, presented similar changes in their levels of expression. An analysis of the regulatory network of a subset of genes in both organisms revealed that the set of regulatory proteins responsible for similar physiological responses observed in the transcriptome analysis are not orthologous. An example of this observation is that of transcription factors mediating catabolic repression for most of the genes that displayed reduced transcript levels in the case of both organisms. In terms of topological functional units in both these bacteria, we found interconnected modules that cluster together genes relating to heat shock, respiratory functions, carbon and peroxide metabolism. Interestingly, B. subtilis functions not found in E. coli, such as sporulation and competence

  14. Norepinephrine transport-mediated gene expression in noradrenergic neurogenesis.

    Science.gov (United States)

    Hu, Yao Fei; Caron, Marc G; Sieber-Blum, Maya

    2009-04-08

    We have identified a differential gene expression profile in neural crest stem cells that is due to deletion of the norepinephrine transporter (NET) gene. NET is the target of psychotropic substances, such as tricyclic antidepressants and the drug of abuse, cocaine. NET mutations have been implicated in depression, anxiety, orthostatic intolerance and attention deficit hyperactivity disorder (ADHD). NET function in adult noradrenergic neurons of the peripheral and central nervous systems is to internalize norepinephrine from the synaptic cleft. By contrast, during embryogenesis norepinephrine (NE) transport promotes differentiation of neural crest stem cells and locus ceruleus progenitors into noradrenergic neurons, whereas NET inhibitors block noradrenergic differentiation. While the structure of NET und the regulation of NET function are well described, little is known about downstream target genes of norepinephrine (NE) transport. We have prepared gene expression profiles of in vitro differentiating wild type and norepinephrine transporter-deficient (NETKO) mouse neural crest cells using long serial analysis of gene expression (LongSAGE). Comparison analyses have identified a number of important differentially expressed genes, including genes relevant to neural crest formation, noradrenergic neuron differentiation and the phenotype of NETKO mice. Examples of differentially expressed genes that affect noradrenergic cell differentiation include genes in the bone morphogenetic protein (BMP) signaling pathway, the Phox2b binding partner Tlx2, the ubiquitin ligase Praja2, and the inhibitor of Notch signaling, Numbl. Differentially expressed genes that are likely to contribute to the NETKO phenotype include dopamine-beta-hydroxylase (Dbh), tyrosine hydroxylase (Th), the peptide transmitter 'cocaine and amphetamine regulated transcript' (Cart), and the serotonin receptor subunit Htr3a. Real-time PCR confirmed differential expression of key genes not only in neural

  15. Norepinephrine transport-mediated gene expression in noradrenergic neurogenesis

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    Sieber-Blum Maya

    2009-04-01

    Full Text Available Abstract Background We have identified a differential gene expression profile in neural crest stem cells that is due to deletion of the norepinephrine transporter (NET gene. NET is the target of psychotropic substances, such as tricyclic antidepressants and the drug of abuse, cocaine. NET mutations have been implicated in depression, anxiety, orthostatic intolerance and attention deficit hyperactivity disorder (ADHD. NET function in adult noradrenergic neurons of the peripheral and central nervous systems is to internalize norepinephrine from the synaptic cleft. By contrast, during embryogenesis norepinephrine (NE transport promotes differentiation of neural crest stem cells and locus ceruleus progenitors into noradrenergic neurons, whereas NET inhibitors block noradrenergic differentiation. While the structure of NET und the regulation of NET function are well described, little is known about downstream target genes of norepinephrine (NE transport. Results We have prepared gene expression profiles of in vitro differentiating wild type and norepinephrine transporter-deficient (NETKO mouse neural crest cells using long serial analysis of gene expression (LongSAGE. Comparison analyses have identified a number of important differentially expressed genes, including genes relevant to neural crest formation, noradrenergic neuron differentiation and the phenotype of NETKO mice. Examples of differentially expressed genes that affect noradrenergic cell differentiation include genes in the bone morphogenetic protein (BMP signaling pathway, the Phox2b binding partner Tlx2, the ubiquitin ligase Praja2, and the inhibitor of Notch signaling, Numbl. Differentially expressed genes that are likely to contribute to the NETKO phenotype include dopamine-β-hydroxylase (Dbh, tyrosine hydroxylase (Th, the peptide transmitter 'cocaine and amphetamine regulated transcript' (Cart, and the serotonin receptor subunit Htr3a. Real-time PCR confirmed differential expression

  16. Antidiabetic and Antihyperlipidemic Effects of Clitocybe nuda on Glucose Transporter 4 and AMP-Activated Protein Kinase Phosphorylation in High-Fat-Fed Mice

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    Mei-Hsing Chen

    2014-01-01

    Full Text Available The objective of this study was to evaluate the antihyperlipidemic and antihyperglycemic effects and mechanism of the extract of Clitocybe nuda (CNE, in high-fat- (HF- fed mice. C57BL/6J was randomly divided into two groups: the control (CON group was fed with a low-fat diet, whereas the experimental group was fed with a HF diet for 8 weeks. Then, the HF group was subdivided into five groups and was given orally CNE (including C1: 0.2, C2: 0.5, and C3: 1.0 g/kg/day extracts or rosiglitazone (Rosi or vehicle for 4 weeks. CNE effectively prevented HF-diet-induced increases in the levels of blood glucose, triglyceride, insulin (P<0.001, P<0.01, P<0.05, resp. and attenuated insulin resistance. By treatment with CNE, body weight gain, weights of white adipose tissue (WAT and hepatic triacylglycerol content were reduced; moreover, adipocytes in the visceral depots showed a reduction in size. By treatment with CNE, the protein contents of glucose transporter 4 (GLUT4 were significantly increased in C3-treated group in the skeletal muscle. Furthermore, CNE reduces the hepatic expression of glucose-6-phosphatase (G6Pase and glucose production. CNE significantly increases protein contents of phospho-AMP-activated protein kinase (AMPK in the skeletal muscle and adipose and liver tissues. Therefore, it is possible that the activation of AMPK by CNE leads to diminished gluconeogenesis in the liver and enhanced glucose uptake in skeletal muscle. It is shown that CNE exhibits hypolipidemic effect in HF-fed mice by increasing ATGL expression, which is known to help triglyceride to hydrolyze. Moreover, antidiabetic properties of CNE occurred as a result of decreased hepatic glucose production via G6Pase downregulation and improved insulin sensitization. Thus, amelioration of diabetic and dyslipidemic states by CNE in HF-fed mice occurred by regulation of GLUT4, G6Pase, ATGL, and AMPK phosphorylation.

  17. Studies of genetic variability of the glucose transporter 2 promoter in patients with type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Møller, A M; Jensen, N M; Pildal, J

    2001-01-01

    This study was performed to test the hypothesis that genetic variation in the promoter of the glucose transporter 2 (GLUT2) might predispose to prediabetic phenotypes or type 2 diabetes. A total of 1611 bp comprising the minimal promoter region of the GLUT2 gene were examined by combined single-s......-tolerant subjects. In conclusion, we found no evidence supporting the hypothesis that genetic variability in the minimal promoter of the GLUT2 is associated with type 2 diabetes or prediabetic phenotypes in the Danish population.......This study was performed to test the hypothesis that genetic variation in the promoter of the glucose transporter 2 (GLUT2) might predispose to prediabetic phenotypes or type 2 diabetes. A total of 1611 bp comprising the minimal promoter region of the GLUT2 gene were examined by combined single...

  18. Transmembrane Domain Single-Nucleotide Polymorphisms Impair Expression and Transport Activity of ABC Transporter ABCG2.

    Science.gov (United States)

    Sjöstedt, Noora; van den Heuvel, Jeroen J M W; Koenderink, Jan B; Kidron, Heidi

    2017-08-01

    To study the function and expression of nine naturally occurring single-nucleotide polymorphisms (G406R, F431L, S441N, P480L, F489L, M515R, L525R, A528T and T542A) that are predicted to reside in the transmembrane regions of the ABC transporter ABCG2. The transport activity of the variants was tested in inside-out membrane vesicles from Sf9 insect and human derived HEK293 cells overexpressing ABCG2. Lucifer Yellow and estrone sulfate were used as probe substrates of activity. The expression levels and cellular localization of the variants was compared to the wild-type ABCG2 by western blotting and immunofluorescence microscopy. All studied variants of ABCG2 displayed markedly decreased transport in both Sf9-ABCG2 and HEK293-ABCG2 vesicles. Impaired transport could be explained for some variants by altered expression levels and cellular localization. Moreover, the destructive effect on transport activity of variants G406R, P480L, M515R and T542A is, to our knowledge, reported for the first time. These results indicate that the transmembrane region of ABCG2 is sensitive to amino acid substitution and that patients harboring these ABCG2 variant forms could suffer from unexpected pharmacokinetic events of ABCG2 substrate drugs or have an increased risk for diseases such as gout where ABCG2 is implicated.

  19. Immune regulation of Rab proteins expression and intracellular transport.

    Science.gov (United States)

    Pei, Gang; Bronietzki, Marc; Gutierrez, Maximiliano Gabriel

    2012-07-01

    Compartmentalization in cells of the immune system, the focus of this review, facilitates the spatiotemporal organization of cellular responses essential for specialized immune functions. In this process of compartment maintenance, Rab proteins are central regulators of protein-mediated transport and fusion of intracellular structures. It is widely believed that the intracellular concentration of proteins that regulate intracellular transport, including Rab proteins, is constitutively mantained. However, there is a growing body of evidence indicating that transcriptional rates of Rab proteins can be modified. This process is especially evident during immune activation and argues that after activation, these cells require higher levels of Rab proteins. The aim of this review is to discuss evidence showing the increasing links between Rab protein expression and intracellular transport, particularly in monocytes and macrophages. We highlight here biological processes in which the expression of Rab GTPases is selectively regulated, leading to the activation of specific intracellular routes. Further, we focus on the immune regulation of intracellular transport after cytokine activation and microbial infection, with an emphasis in mycobacterial infection.

  20. Expression of Vesicular Nucleotide Transporter in Rat Odontoblasts

    International Nuclear Information System (INIS)

    Ikeda, Erina; Goto, Tetsuya; Gunjigake, Kaori; Kuroishi, Kayoko; Ueda, Masae; Kataoka, Shinji; Toyono, Takashi; Nakatomi, Mitsushiro; Seta, Yuji; Kitamura, Chiaki; Nishihara, Tatsuji; Kawamoto, Tatsuo

    2016-01-01

    Several theories have been proposed regarding pain transmission mechanisms in tooth. However, the exact signaling mechanism from odontoblasts to pulp nerves remains to be clarified. Recently, ATP-associated pain transmission has been reported, but it is unclear whether ATP is involved in tooth pain transmission. In the present study, we focused on the vesicular nucleotide transporter (VNUT), a transporter of ATP into vesicles, and examined whether VNUT was involved in ATP release from odontoblasts. We examined the expression of VNUT in rat pulp by RT-PCR and immunostaining. ATP release from cultured odontoblast-like cells with heat stimulation was evaluated using ATP luciferase methods. VNUT was expressed in pulp tissue, and the distribution of VNUT-immunopositive vesicles was confirmed in odontoblasts. In odontoblasts, some VNUT-immunopositive vesicles were colocalized with membrane fusion proteins. Additionally P2X 3 , an ATP receptor, immunopositive axons were distributed between odontoblasts. The ATP release by thermal stimulation from odontoblast-like cells was inhibited by the addition of siRNA for VNUT. These findings suggest that cytosolic ATP is transported by VNUT and that the ATP in the vesicles is then released from odontoblasts to ATP receptors on axons. ATP vesicle transport in odontoblasts seems to be a key mechanism for signal transduction from odontoblasts to axons in the pulp

  1. Synthesis of L-rhamnose derived chiral bicyclic triazoles as novel sodium-glucose transporter (SGLT) inhibitors.

    Science.gov (United States)

    Putapatri, Siddamal Reddy; Kanwal, Abhinav; Sridhar, Balasubramanian; Banerjee, Sanjay K; Kantevari, Srinivas

    2014-11-14

    Herein we describe the synthesis of a series of novel fused bicyclic 1,2,3-triazoles from commercially available, natural deoxy sugar, L-rhamnose. The key reactions involved are (i) Zn(OTf)2 catalyzed enantioselective alkynylation of L-rhamnose derived azidoaldehyde and (ii) deprotection of the acid sensitive 1,2-isopropylidene group followed by in situ intramolecular click-cycloaddition of azidoalkynols. Some compounds exhibit excellent sodium-glucose transporter (SGLT1 and SGLT2) inhibition activity.

  2. Characterization of an ADP-glucose pyrophosphorylase small subunit gene expressed in developing cotton (Gossypium hirsutum) fibers.

    Science.gov (United States)

    Taliercio, Earl

    2011-06-01

    ADP-glucose pyrophosphorylase (ADPGp, EC 2.7.7.27) is a tetrameric protein composed of two small and two large subunits that catalyzes the biosynthesis of ADP-glucose from glucose-phosphate which is used to provide the glucose subunits for starch biosynthesis. A second cotton gene encoding an ADPGp small subunit has been cloned and characterized. The gene contains eight introns similar to previously reported potato and cotton ADPGp small subunit genes. The deduced translation of the gene contained a poorly conserved transit peptide and well conserved catalytic and regulatory elements typical of other plant ADPGps. The 5' end of the mRNA was cloned and sequenced to identify the transcriptional start site (TSS). The promoter region upstream of the TSS did not contain the core promoter sequence in the typical positions indicating this gene may not use a standard core promoter. Other sequence motifs associated with tissue specific expression and phytohormone response were present. Reverse transcription (RT)-PCR with gene specific primers identified the sites of expression of this gene. Expression was most abundant in the meristem region, and immature stem and relatively lower in starch accumulating roots demonstrating that this gene has a different pattern of expression than the previously reported cotton ADPGp small subunit gene. Additionally this gene was differentially expressed in cotton fibers. The presence of starch was confirmed in developing cotton fibers suggesting that starch metabolism plays a role in cotton fiber development.

  3. Cloning and expression of the Clostridium thermosulfurogenes glucose isomerase gene in Escherichia coli and Bacillus subtilis.

    OpenAIRE

    Lee, C Y; Bhatnagar, L; Saha, B C; Lee, Y E; Takagi, M; Imanaka, T; Bagdasarian, M; Zeikus, J G

    1990-01-01

    The gene that encodes thermostable glucose isomerase in Clostridium thermosulfurogenes was cloned by complementation of glucose isomerase activity in a xylA mutant of Escherichia coli. A new assay method for thermostable glucose isomerase activity on agar plates, using a top agar mixture containing fructose, glucose oxidase, peroxidase, and benzidine, was developed. One positive clone, carrying plasmid pCGI38, was isolated from a cosmid library of C. thermosulfurogenes DNA. The plasmid was fu...

  4. High glucose-induced oxidative stress represses sirtuin deacetylase expression and increases histone acetylation leading to neural tube defects.

    Science.gov (United States)

    Yu, Jingwen; Wu, Yanqing; Yang, Peixin

    2016-05-01

    Aberrant epigenetic modifications are implicated in maternal diabetes-induced neural tube defects (NTDs). Because cellular stress plays a causal role in diabetic embryopathy, we investigated the possible role of the stress-resistant sirtuin (SIRT) family histone deacetylases. Among the seven sirtuins (SIRT1-7), pre-gestational maternal diabetes in vivo or high glucose in vitro significantly reduced the expression of SIRT 2 and SIRT6 in the embryo or neural stem cells, respectively. The down-regulation of SIRT2 and SIRT6 was reversed by superoxide dismutase 1 (SOD1) over-expression in the in vivo mouse model of diabetic embryopathy and the SOD mimetic, tempol and cell permeable SOD, PEGSOD in neural stem cell cultures. 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), a superoxide generating agent, mimicked high glucose-suppressed SIRT2 and SIRT6 expression. The acetylation of histone 3 at lysine residues 56 (H3K56), H3K14, H3K9, and H3K27, putative substrates of SIRT2 and SIRT6, was increased by maternal diabetes in vivo or high glucose in vitro, and these increases were blocked by SOD1 over-expression or tempol treatment. SIRT2 or SIRT6 over-expression abrogated high glucose-suppressed SIRT2 or SIRT6 expression, and prevented the increase in acetylation of their histone substrates. The potent sirtuin activator (SRT1720) blocked high glucose-increased histone acetylation and NTD formation, whereas the combination of a pharmacological SIRT2 inhibitor and a pan SIRT inhibitor mimicked the effect of high glucose on increased histone acetylation and NTD induction. Thus, diabetes in vivo or high glucose in vitro suppresses SIRT2 and SIRT6 expression through oxidative stress, and sirtuin down-regulation-induced histone acetylation may be involved in diabetes-induced NTDs. The mechanism underlying pre-gestational diabetes-induced neural tube defects (NTDs) is still elusive. Our study unravels a new epigenetic mechanism in which maternal diabetes-induced oxidative stress represses

  5. Involvement of KLF11 in hepatic glucose metabolism in mice via suppressing of PEPCK-C expression.

    Directory of Open Access Journals (Sweden)

    Huabing Zhang

    Full Text Available Abnormal hepatic gluconeogenesis is related to hyperglycemia in mammals with insulin resistance. Despite the strong evidences linking Krüppel-like factor 11 (KLF11 gene mutations to development of Type 2 diabetes, the precise physiological functions of KLF11 in vivo remain largely unknown.In current investigation, we showed that KLF11 is involved in modulating hepatic glucose metabolism in mice. Overexpression of KLF11 in primary mouse hepatocytes could inhibit the expression of gluconeogenic genes, including phosphoenolpyruvate carboxykinase (cytosolic isoform, PEPCK-C and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α, subsequently decreasing the cellular glucose output. Diabetic mice with overexpression of KLF11 gene in livers significantly ameliorated hyperglycemia and glucose intolerance; in contrast, the knockdown of KLF11 expression in db/m and C57BL/6J mice livers impaired glucose tolerance.Our data strongly indicated the involvement of KLF11 in hepatic glucose homeostasis via modulating the expression of PEPCK-C.

  6. Absence of Carbohydrate Response Element Binding Protein in Adipocytes Causes Systemic Insulin Resistance and Impairs Glucose Transport.

    Science.gov (United States)

    Vijayakumar, Archana; Aryal, Pratik; Wen, Jennifer; Syed, Ismail; Vazirani, Reema P; Moraes-Vieira, Pedro M; Camporez, Joao Paulo; Gallop, Molly R; Perry, Rachel J; Peroni, Odile D; Shulman, Gerald I; Saghatelian, Alan; McGraw, Timothy E; Kahn, Barbara B

    2017-10-24

    Lower adipose-ChREBP and de novo lipogenesis (DNL) are associated with insulin resistance in humans. Here, we generated adipose-specific ChREBP knockout (AdChREBP KO) mice with negligible sucrose-induced DNL in adipose tissue (AT). Chow-fed AdChREBP KO mice are insulin resistant with impaired insulin action in the liver, muscle, and AT and increased AT inflammation. HFD-fed AdChREBP KO mice are also more insulin resistant than controls. Surprisingly, adipocytes lacking ChREBP display a cell-autonomous reduction in insulin-stimulated glucose transport that is mediated by impaired Glut4 translocation and exocytosis, not lower Glut4 levels. AdChREBP KO mice have lower levels of palmitic acid esters of hydroxy stearic acids (PAHSAs) in serum, and AT. 9-PAHSA supplementation completely rescues their insulin resistance and AT inflammation. 9-PAHSA also normalizes impaired glucose transport and Glut4 exocytosis in ChREBP KO adipocytes. Thus, loss of adipose-ChREBP is sufficient to cause insulin resistance, potentially by regulating AT glucose transport and flux through specific lipogenic pathways. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. Maltose and maltodextrin utilization by Listeria monocytogenes depend on an inducible ABC transporter which is repressed by glucose.

    Directory of Open Access Journals (Sweden)

    Shubha Gopal

    2010-04-01

    Full Text Available In the environment as well as in the vertebrate intestine, Listeriae have access to complex carbohydrates like maltodextrins. Bacterial exploitation of such compounds requires specific uptake and utilization systems.We could show that Listeria monocytogenes and other Listeria species contain genes/gene products with high homology to the maltodextrin ABC transporter and utilization system of B. subtilis. Mutant construction and growth tests revealed that the L. monocytogenes gene cluster was required for the efficient utilization of maltodextrins as well as maltose. The gene for the ATP binding protein of the transporter was located distant from the cluster. Transcription analyses demonstrated that the system was induced by maltose/maltodextrins and repressed by glucose. Its induction was dependent on a LacI type transcriptional regulator. Repression by glucose was independent of the catabolite control protein CcpA, but was relieved in a mutant defective for Hpr kinase/phosphorylase.The data obtained show that in L. monocytogenes the uptake of maltodextrin and, in contrast to B. subtilis, also maltose is exclusively mediated by an ABC transporter. Furthermore, the results suggest that glucose repression of the uptake system possibly is by inducer exclusion, a mechanism not described so far in this organism.

  8. Identification of the glucose transporter in mammalian cell membranes using an /sup 125/(I)-forskolin photoaffinity label

    Energy Technology Data Exchange (ETDEWEB)

    Ruoho, A.; Wadzinski, B.; Shanahan, M.

    1987-05-01

    The glucose transporter has been identified in a variety of mammlian cell membranes using a carrier-free photoactivatable radioiodinated derivative of forskolin, 3-iodo-4-azidophenethylamido-7-0-succinyldeacetyl-forskolin, (I-125)IAPS-Fsk, at 1-10 nM. The membranes which have been photolabeled with (I-125)IAPS-Fsk are: rat cardiac sarcolemmal membranes, rat cortex and cerebellum synaptic membranes, human placental membranes, and wild type S49 lymphoma cell membranes. The glucose transporter in rat cardiac sarcolemmal membranes and rat cortex and cerebellum synaptic membranes was determined to be 45 kDa by SDS-PAGE. Photolysis of human placental membranes and S49 lymphoma membranes with (I-125)IAPS-Fsk followed by SDS-PAGE indicated specific derivatization of a broad band (45-55 kDa) in placental membranes and a narrower band (45 kDa) in the S49 lymphoma membranes. Digestion of the (I-125)IPAS-Fsk labelled placental and S49 lymphoma membranes with endo-B-galactosidase showed a reduction in the apparent molecular weight of the radiolabelled band to 40 kDa. Trypsinization of labelled placental and lymphoma membranes produced an 18 kDa radiolabelled proteolytic fragment. (I-125)IAPS-Fsk is a highly effective probe for identifying low levels of glucose transporters in mammalian tissues.

  9. Identification of the glucose transporter in mammalian cell membranes using an 125(I)-forskolin photoaffinity label

    International Nuclear Information System (INIS)

    Ruoho, A.; Wadzinski, B.; Shanahan, M.

    1987-01-01

    The glucose transporter has been identified in a variety of mammlian cell membranes using a carrier-free photoactivatable radioiodinated derivative of forskolin, 3-iodo-4-azidophenethylamido-7-0-succinyldeacetyl-forskolin, [I-125]IAPS-Fsk, at 1-10 nM. The membranes which have been photolabeled with [I-125]IAPS-Fsk are: rat cardiac sarcolemmal membranes, rat cortex and cerebellum synaptic membranes, human placental membranes, and wild type S49 lymphoma cell membranes. The glucose transporter in rat cardiac sarcolemmal membranes and rat cortex and cerebellum synaptic membranes was determined to be 45 kDa by SDS-PAGE. Photolysis of human placental membranes and S49 lymphoma membranes with [I-125]IAPS-Fsk followed by SDS-PAGE indicated specific derivatization of a broad band (45-55 kDa) in placental membranes and a narrower band (45 kDa) in the S49 lymphoma membranes. Digestion of the [I-125]IPAS-Fsk labelled placental and S49 lymphoma membranes with endo-B-galactosidase showed a reduction in the apparent molecular weight of the radiolabelled band to 40 kDa. Trypsinization of labelled placental and lymphoma membranes produced an 18 kDa radiolabelled proteolytic fragment. [I-125]IAPS-Fsk is a highly effective probe for identifying low levels of glucose transporters in mammalian tissues

  10. Absence of Carbohydrate Response Element Binding Protein in Adipocytes Causes Systemic Insulin Resistance and Impairs Glucose Transport

    Directory of Open Access Journals (Sweden)

    Archana Vijayakumar

    2017-10-01

    Full Text Available Lower adipose-ChREBP and de novo lipogenesis (DNL are associated with insulin resistance in humans. Here, we generated adipose-specific ChREBP knockout (AdChREBP KO mice with negligible sucrose-induced DNL in adipose tissue (AT. Chow-fed AdChREBP KO mice are insulin resistant with impaired insulin action in the liver, muscle, and AT and increased AT inflammation. HFD-fed AdChREBP KO mice are also more insulin resistant than controls. Surprisingly, adipocytes lacking ChREBP display a cell-autonomous reduction in insulin-stimulated glucose transport that is mediated by impaired Glut4 translocation and exocytosis, not lower Glut4 levels. AdChREBP KO mice have lower levels of palmitic acid esters of hydroxy stearic acids (PAHSAs in serum, and AT. 9-PAHSA supplementation completely rescues their insulin resistance and AT inflammation. 9-PAHSA also normalizes impaired glucose transport and Glut4 exocytosis in ChREBP KO adipocytes. Thus, loss of adipose-ChREBP is sufficient to cause insulin resistance, potentially by regulating AT glucose transport and flux through specific lipogenic pathways.

  11. Expression and putative role of mitochondrial transport proteins in cancer.

    Science.gov (United States)

    Lytovchenko, Oleksandr; Kunji, Edmund R S

    2017-08-01

    Cancer cells undergo major changes in energy and biosynthetic metabolism. One of them is the Warburg effect, in which pyruvate is used for fermentation rather for oxidative phosphorylation. Another major one is their increased reliance on glutamine, which helps to replenish the pool of Krebs cycle metabolites used for other purposes, such as amino acid or lipid biosynthesis. Mitochondria are central to these alterations, as the biochemical pathways linking these processes run through these organelles. Two membranes, an outer and inner membrane, surround mitochondria, the latter being impermeable to most organic compounds. Therefore, a large number of transport proteins are needed to link the biochemical pathways of the cytosol and mitochondrial matrix. Since the transport steps are relatively slow, it is expected that many of these transport steps are altered when cells become cancerous. In this review, changes in expression and regulation of these transport proteins are discussed as well as the role of the transported substrates. This article is part of a Special Issue entitled Mitochondria in Cancer, edited by Giuseppe Gasparre, Rodrigue Rossignol and Pierre Sonveaux. Copyright © 2017. Published by Elsevier B.V.

  12. Glucose Transporter 1–Dependent Glycolysis Is Increased during Aging-Related Lung Fibrosis, and Phloretin Inhibits Lung Fibrosis

    Science.gov (United States)

    Cho, Soo Jung; Moon, Jong-Seok; Lee, Chang-Min; Choi, Augustine M. K.

    2017-01-01

    Aging is associated with metabolic diseases such as type 2 diabetes mellitus, cardiovascular disease, cancer, and neurodegeneration. Aging contributes to common processes including metabolic dysfunction, DNA damage, and reactive oxygen species generation. Although glycolysis has been linked to cell growth and proliferation, the mechanisms by which the activation of glycolysis by aging regulates fibrogenesis in the lung remain unclear. The objective of this study was to determine if glucose transporter 1 (GLUT1)–induced glycolysis regulates age-dependent fibrogenesis of the lung. Mouse and human lung tissues were analyzed for GLUT1 and glycolytic markers using immunoblotting. Glycolytic function was measured using a Seahorse apparatus. To study the effect of GLUT1, genetic inhibition of GLUT1 was performed by short hairpin RNA transduction, and phloretin was used for pharmacologic inhibition of GLUT1. GLUT1-dependent glycolysis is activated in aged lung. Genetic and pharmacologic inhibition of GLUT1 suppressed the protein expression of α-smooth muscle actin, a key cytoskeletal component of activated fibroblasts, in mouse primary lung fibroblast cells. Moreover, we demonstrated that the activation of AMP-activated protein kinase, which is regulated by GLUT1-dependent glycolysis, represents a critical metabolic pathway for fibroblast activation. Furthermore, we demonstrated that phloretin, a potent inhibitor of GLUT1, significantly inhibited bleomycin-induced lung fibrosis in vivo. These results suggest that GLUT1-dependent glycolysis regulates fibrogenesis in aged lung and that inhibition of GLUT1 provides a potential target of therapy of age-related lung fibrosis. PMID:27997810

  13. Expression of genes involved in lipid metabolism in men with impaired glucose tolerance : impact of insulin stimulation and weight loss

    NARCIS (Netherlands)

    Konings, E.; Corpeleijn, E.; Bouwman, F.G.; Mariman, E.C.; Blaak, E.E.

    2010-01-01

    Background: The impaired glucose tolerance (IGT) state is characterized by insulin resistance. Disturbances in fatty acid (FA) metabolism may underlie this reduced insulin sensitivity. The aim of this study was to investigate whether the prediabetic state is accompanied by changes in the expression

  14. [Contents of the glucose transporters GLUT1 and GLUT4 in oxidative and glycolytic muscles of goat kids and adult goats].

    Science.gov (United States)

    Dühlmeier, R; Voigt, J; Breves, G; Sallmann, H P

    2005-11-01

    The objective of this study was to elucidate, whether the impaired insulin sensitivity with regard to glucose utilisation in ruminating goats compared with suckling goat kids may be due to a reduced expression of the glucose transporters GLUT1 and GLUT4 in skeletal muscle. Muscle samples were removed from red, oxidative muscles (M. masseter, diaphragm) and white, glycolytic muscles (M. longissimus dorsi, and M. semitendinosus) of five goat kids fed with milk exchanger and nine adult goats of different stages of life. Samples were analysed for their GLUT1 and GLUT4 contents. The muscles were characterised metabolically by measuring the activities of isocitrate dehydrogenase (ICDH) and of lactate dehydrogenase. In all four analysed muscles the GLUT4 contents of adult goats were significantly (p kids. Significant differences concerning the GLUT4 contents in skeletal muscles were not detected in adult goats of different stages of life. The GLUT1 contents differed to a lower extend between goat kids and adult goats. The results of this investigation indicate that the impaired insulin sensitivity of adult compared with suckling ruminants is accompanied by or leads to a decreased GLUT4 expression.

  15. Empagliflozin: a new sodium-glucose co-transporter 2 (SGLT2 inhibitor for the treatment of type 2 diabetes

    Directory of Open Access Journals (Sweden)

    Joshua J Neumiller

    2014-06-01

    Full Text Available Type 2 diabetes is increasing in prevalence worldwide, and hyperglycemia is often poorly controlled despite a number of therapeutic options. Unlike previously available agents, sodium-glucose co-transporter 2 (SGLT2 inhibitors offer an insulin-independent mechanism for improving blood glucose levels, since they promote urinary glucose excretion (UGE by inhibiting glucose reabsorption in the kidney. In addition to glucose control, SGLT2 inhibitors are associated with weight loss and blood pressure reductions, and do not increase the risk of hypoglycemia. Empagliflozin is a selective inhibitor of SGLT2, providing dose-dependent UGE increases in healthy volunteers, with up to 90 g of glucose excreted per day. It can be administered orally, and studies of people with renal or hepatic impairment indicated empagliflozin needed no dose adjustment based on pharmacokinetics. In Phase II trials in patients with type 2 diabetes, empagliflozin provided improvements in glycosylated hemoglobin (HbA1c and other measures of glycemic control when given as monotherapy or add-on to metformin, as well as reductions in weight and systolic blood pressure. As add-on to basal insulin, empagliflozin not only improved HbA1c levels but also reduced insulin doses. Across studies, empagliflozin was generally well tolerated with a similar rate of hypoglycemia to placebo; however, patients had a slightly increased frequency of genital infections, but not urinary tract infections, versus placebo. Phase III studies have also reported a good safety profile along with significant improvements in HbA1c, weight and blood pressure, with no increased risk of hypoglycemia versus placebo. Based on available data, it appears that empagliflozin may be a useful option in a range of patients; however, clinical decisions will be better informed by the results of ongoing studies, in particular, a large cardiovascular outcome study (EMPA-REG OUTCOME™.

  16. The Role of Hypoxia-Inducible Factor-1α, Glucose Transporter-1, (GLUT-1 and Carbon Anhydrase IX in Endometrial Cancer Patients

    Directory of Open Access Journals (Sweden)

    Pawel Sadlecki

    2014-01-01

    Full Text Available Hypoxia-inducible factor-1α (HIF-1α, glucose transporter-1 (GLUT-1, and carbon anhydrase IX (CAIX are important molecules that allow adaptation to hypoxic environments. The aim of our study was to investigate the correlation between HIF-1α, GLUT-1, and CAIX protein level with the clinicopathological features of endometrial cancer patients. Materials and Methods. 92 endometrial cancer patients, aged 37–84, were enrolled to our study. In all patients clinical stage, histologic grade, myometrial invasion, lymph node, and distant metastases were determined. Moreover, the survival time was assessed. Immunohistochemical analyses were performed on archive formalin fixed paraffin embedded tissue sections. Results. High significant differences (P=0.0115 were reported between HIF-1α expression and the histologic subtype of cancer. Higher HIF-1α expression was associated with the higher risk of recurrence (P=0.0434. The results of GLUT-1 and CAIX expression did not reveal any significant differences between the proteins expression in the primary tumor and the clinicopathological features. Conclusion. The important role of HIF-1α in the group of patients with the high risk of recurrence and the negative histologic subtype of the tumor suggest that the expression of this factor might be useful in the panel of accessory pathomorphological tests and could be helpful in establishing more accurate prognosis in endometrial cancer patients.

  17. Flozins, inhibitors of type 2 renal sodium-glucose co-transporter – not only antihyperglycemic drugs

    Directory of Open Access Journals (Sweden)

    Mizerski Grzegorz

    2015-09-01

    Full Text Available The kidneys play a crucial role in the regulation of the carbohydrate metabolism. In normal physiological conditions, the glucose that filters through the renal glomeruli is subsequently nearly totally reabsorbed in the proximal renal tubules. Two transporters are engaged in this process: sodium-glucose co-transporter type 1 (SGLT1, and sodium-glucose co-transporter type type 2 (SGLT2 - this being located in the luminal membrane of the renal tubular epithelial cells. It was found that the administration of dapagliflozin, a selective SGLT2 inhibitor, in patients with type 2 diabetes, is associated with the reduction of HbA1c concentration by 0.45-1.11%. Additional benefits from the treatment with dapagliflozin are the reduction of arterial blood pressure and a permanent reduction of body weight. This outcome is related to the effect of osmotic diuresis and to the considerable loss of the glucose load by way of urine excretion. Dapagliflozin may be successfully applied in type 2 diabetes monotherapy, as well as in combined therapy (including insulin, where it is equally effective as other oral anti-diabetic drugs. Of note: serious adverse effects of dapagliflozin administration are rarely observed. What is more, episodes of severe hypoglycaemia related with the treatment occur only sporadically, most often in the course of diabetes polytherapy. The most frequent effects of the SGLT2 inhibitors are inseparably associated with the mechanism of their action (the glucuretic effect, and cover urogenital infections with a mild clinical course. At present, clinical trials are being continued of the administration of several subsequent drugs from this group, the most advanced of these being the use of canagliflozin and empagliflozin.

  18. Pre- and postprandial electroencephalography in glucose transporter type 1 deficiency syndrome: an illustrative case to discuss the concept of carbohydrate responsiveness.

    Science.gov (United States)

    Parolin, Giulia; Drigo, Paola; Toldo, Irene; Boniver, Clementina; Gatta, Michela; Burlina, Alberto; Laverda, Anna Maria; Sartori, Stefano

    2011-01-01

    Glucose transporter type 1 deficiency syndrome is an inborn error of glucose transport across the blood-brain barrier with hypoglychorrachia. Patients usually present developmental delay, movement disorders, seizures, and acquired microcephaly, variously associated and leading to different phenotypes. We report a 3-year-old girl affected by glucose transporter type 1 deficiency syndrome with carbohydrate responsiveness. Her history was characterized by worsening of ataxia with an increasing interval to the last food intake, occurrence of seizures in the morning before breakfast, slowing of electroencephalogram (EEG) background activity with the appearance of epileptiform discharges during preprandial recordings, and improvement of the electroclinical picture after food intake. By adding a new case to the pertinent literature, we stress the role of pre- and postprandial EEG recordings for the identification of individuals potentially affected by glucose transporter type 1 deficiency syndrome. We also provide a possible physiopathological interpretation of EEG changes related to food intake.

  19. Anti-diabetic potential of Catharanthus roseus Linn. and its effect on the glucose transport gene (GLUT-2 and GLUT-4) in streptozotocin induced diabetic wistar rats.

    Science.gov (United States)

    Al-Shaqha, Waleed M; Khan, Mohsin; Salam, Nasir; Azzi, Arezki; Chaudhary, Anis Ahmad

    2015-10-21

    Catharanthus roseus is an important Ayurvedic medication in traditional medicine. It is potentially used in countries like India, South Africa, China and Malaysia for the healing of diabetes mellitus. Although, the molecular mechanisms behind this effect are yet to be exclusively explored. Due to the great antidiabetic and hyperlipidemic potential of c. roseus, we hypothesized that the insulin mimetic effect of ethanolic extract of c. roseus might add to glucose uptake through improvement in the expression of genes of the glucose transporter (GLUT) family messenger RNA (mRNA) in liver. STZ-induced diabetic rats treated by ethanolic extract of c. roseus 100 mg/kg and 200 mg/kg; and one group treated with Metformin (100 mg/kg). After final administration of treatment of 4 weeks, blood samples were collected under fasting conditions, and the body weights (BWs) were measured. Total RNA from liver was extracted with the Qiagen RNEasy Micro kit (GERMANY) as described in the manufacturer's instructions. First-strand complementary DNA (cDNA) was synthesized at 40 °C by priming with oligo-dT12-18 (Invitrogen, USA) and using Super ScriptII reverse transcriptase according to the protocol provided by the manufacturer (Invitrogen, USA). Real-time polymerase chain reaction (PCR) amplifications for GLUT-4 (gene ID: 25139) were conducted using Light-Cycler 480 (Roche, USA) with the SyBr® I nucleic acid stain (Invitrogen, USA) according to the manufacturer's instructions. Polymerase chain reaction products of β-actin primer gene were used as an internal standard. The proposed study was framed to look at the antidiabetic efficacy of ethanolic extract of c. roseus and an expression of GLUT-2 and GLUT-4 gene in streptozotocin induced diabetic wistar rats. The doses were administered orally at a rate of 100 and 200 mg/kg and detrain the glucose transport system in liver for 4 weeks. The observed results showed a good positive correlation between intracellular calcium and insulin

  20. hGH-V gene expression and promoter activity under glucose and 5-azacytidine (5azaC) effects.

    Science.gov (United States)

    de Jesús Romero-Prado, Marina Maria; Barrera-Saldaña, Hugo A; Castrillo-Diez, Jose Luis

    2010-02-15

    The metabolic conditions affecting placental development depend on nutritional state, genetic constitution and other external factors. The secretion of human placental growth hormone (hGH-V) had shown to be dependent of glucose, but the regulatory effects of this metabolite on hGH-V promoter activity and gene expression in presence of 5-azacytidine had not been studied. In this work we compared the hGH-V promoter activity and the endogenous mRNA expression in human placental choriocarcinoma cell line JAR in the presence of glucose and demethylating genome conditions. High glucose concentration in culture medium diminished hGH-V mRNA endogenous levels in JAR cells whereas the expression of hGH-V from transfected PACs was slightly higher; but in the presence of 5azaC a higher hGH-V gene expression from both the endogenous and the transfected ones was obtained. A drastic diminution of promoter analysis was shown when cells had no glucose (J0 cells) or in presence of 5azaC; the placental transcription factors that showed modified binding capacity were HES-2, PPAR-gamma, H4TF-1 and OCT-1. Our results suggest that in vitro suppressive glucose effect dictates a metabolic context to hGH-V gene expression and promoter regulation whereas a genomic methylation-dependent background is necessary to maintain placental transcription factors able to bind and regulate proximal promoter region of hGH-V in placental cells. Crown Copyright 2009. Published by Elsevier B.V. All rights reserved.

  1. Vocal fold ion transport and mucin expression following acrolein exposure.

    Science.gov (United States)

    Levendoski, Elizabeth Erickson; Sivasankar, M Preeti

    2014-05-01

    The vocal fold epithelium is exposed to inhaled particulates including pollutants during breathing in everyday environments. Yet, our understanding of the effects of pollutants on vocal fold epithelial function is extremely limited. The objective of this study was to investigate the effect of the pollutant acrolein on two vocal fold epithelial mechanisms: ion transport and mucin (MUC) synthesis. These mechanisms were chosen as each plays a critical role in vocal defense and in maintaining surface hydration which is necessary for optimal voice production. Healthy, native porcine vocal folds (N = 85) were excised and exposed to an acrolein or sham challenge. A 60-min acrolein, but not sham challenge significantly reduced ion transport and inhibited cyclic adenosine monophosphate-dependent, increases in ion transport. Decreases in ion transport were associated with reduced sodium absorption. Within the same timeline, no significant acrolein-induced changes in MUC gene or protein expression were observed. These results improve our understanding of the effects of acrolein on key vocal fold epithelial functions and inform the development of future investigations that seek to elucidate the impact of a wide range of pollutant exposures on vocal fold health.

  2. Cholesterol Transporters ABCA1 and ABCG1 Gene Expression in Peripheral Blood Mononuclear Cells in Patients with Metabolic Syndrome

    Directory of Open Access Journals (Sweden)

    Zahra Tavoosi

    2015-01-01

    Full Text Available ABCA1 and ABCG1 genes encode the cholesterol transporter proteins that play a key role in cholesterol and phospholipids homeostasis. This study was aimed at evaluating and comparing ABCA1 and ABCG1 genes expression in metabolic syndrome patients and healthy individuals. This case-control study was performed on 36 patients with metabolic syndrome and the same number of healthy individuals in Hamadan (west of Iran during 2013-2014. Total RNA was extracted from mononuclear cells and purified using RNeasy Mini Kit column. The expression of ABCA1 and ABCG1 genes was performed by qRT-PCR. Lipid profile and fasting blood glucose were measured using colorimetric procedures. ABCG1 expression in metabolic syndrome patients was significantly lower (about 75% compared to that of control group, while for ABCA1 expression, there was no significant difference between the two studied groups. Comparison of other parameters such as HDL-C, FBS, BMI, waist circumference, and systolic and diastolic blood pressure between metabolic syndrome patients and healthy individuals showed significant differences (P<0.05. Decrease in ABCG1 expression in metabolic syndrome patients compared to healthy individuals suggests that hyperglycemia, related metabolites, and hyperlipidemia over the transporter capacity resulted in decreased expression of ABCG1. Absence of a significant change in ABCA1 gene expression between two groups can indicate a different regulation mechanism for ABCA1 expression.

  3. High glucose promotes the migration of retinal pigment epithelial cells through increased oxidative stress and PEDF expression

    Science.gov (United States)

    Farnoodian, Mitra; Halbach, Caroline; Slinger, Cassidy; Pattnaik, Bikash R.; Sorenson, Christine M.

    2016-01-01

    Defects in the outer blood-retinal barrier have significant impact on the pathogenesis of diabetic retinopathy and macular edema. However, the detailed mechanisms involved remain largely unknown. This is, in part, attributed to the lack of suitable animal and cell culture models, including those of mouse origin. We recently reported a method for the culture of retinal pigment epithelial (RPE) cells from wild-type and transgenic mice. The RPE cells are responsible for maintaining the integrity of the outer blood-retinal barrier whose dysfunction during diabetes has a significant impact on vision. Here we determined the impact of high glucose on the function of RPE cells. We showed that high glucose conditions resulted in enhanced migration and increased the level of oxidative stress in RPE cells, but minimally impacted their rate of proliferation and apoptosis. High glucose also minimally affected the cell-matrix and cell-cell interactions of RPE cells. However, the expression of integrins and extracellular matrix proteins including pigment epithelium-derived factor (PEDF) were altered under high glucose conditions. Incubation of RPE cells with the antioxidant N-acetylcysteine under high glucose conditions restored normal migration and PEDF expression. These cells also exhibited increased nuclear localization of the antioxidant transcription factor Nrf2 and ZO-1, reduced levels of β-catenin and phagocytic activity, and minimal effect on production of vascular endothelial growth factor, inflammatory cytokines, and Akt, MAPK, and Src signaling pathways. Thus high glucose conditions promote RPE cell migration through increased oxidative stress and expression of PEDF without a significant effect on the rate of proliferation and apoptosis. PMID:27440660

  4. Improving xylitol production at elevated temperature with engineered Kluyveromyces marxianus through over-expressing transporters.

    Science.gov (United States)

    Zhang, Jia; Zhang, Biao; Wang, Dongmei; Gao, Xiaolian; Hong, Jiong

    2015-01-01

    Three transporter genes including Kluyveromyces marxianus aquaglyceroporin gene (KmFPS1), Candida intermedia glucose/xylose facilitator gene (CiGXF1) or glucose/xylose symporter gene (CiGXS1) were over-expressed in K. marxianus YZJ017 to improve xylitol production at elevated temperatures. The xylitol production of YZJ074 that harbored CiGXF1 was improved to 147.62g/L in Erlenmeyer flask at 42°C. In fermenter, 99.29 and 149.60g/L xylitol were produced from 99.55 and 151.91g/L xylose with productivity of 4.14 and 3.40g/L/h respectively at 42°C. Even at 45°C, YZJ074 could produce 101.30g/L xylitol from 101.41g/L xylose with productivity of 2.81g/L/h. Using fed-batch fermentation through repeatedly adding non-sterilized substrate directly, YZJ074 could produce 312.05g/L xylitol which is the highest yield reported to date. The engineered strains YZJ074 which can produce xylitol at elevated temperatures is an excellent foundation for xylitol bioconversion. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Spexin peptide is expressed in human endocrine and epithelial tissues and reduced after glucose load in type 2 diabetes.

    Science.gov (United States)

    Gu, Liping; Ma, Yuhang; Gu, Mingyu; Zhang, Ying; Yan, Shuai; Li, Na; Wang, Yufan; Ding, Xiaoying; Yin, Jiajing; Fan, Nengguang; Peng, Yongde

    2015-09-01

    Spexin mRNA and protein are widely expressed in rat tissues and associate with weight loss in rodents of diet-induced obesity. Its location in endocrine and epithelial cells has also been suggested. Spexin is a novel peptide that involves weight loss in rodents of diet-induced obesity. Therefore, we aimed to examine its expression in human tissues and test whether spexin could have a role in glucose and lipid metabolism in type 2 diabetes mellitus (T2DM). The expression of the spexin gene and immunoreactivity in the adrenal gland, skin, stomach, small intestine, liver, thyroid, pancreatic islets, visceral fat, lung, colon, and kidney was higher than that in the muscle and connective tissue. Immunoreactive serum spexin levels were reduced in T2DM patients and correlated with fasting blood glucose (FBG, r=-0.686, Pepithelial tissues, indicating that spexin may be involved in physiological functions of endocrine and in several other tissues. Circulating spexin levels are low in T2DM patients and negatively related to blood glucose and lipids suggesting that the peptide may play a role in glucose and lipid metabolism in T2DM. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

  6. 2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxy-β-D-pyranoside confers neuroprotection in cell and animal models of ischemic stroke through calpain1/PKA/CREB-mediated induction of neuronal glucose transporter 3

    International Nuclear Information System (INIS)

    Yu, Shu; Cheng, Qiong; Li, Lu; Liu, Mei; Yang, Yumin; Ding, Fei

    2014-01-01

    Salidroside is proven to be a neuroprotective agent of natural origin, and its analog, 2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxy-β-D-pyranoside (named SalA-4 g), has been synthesized in our lab. In this study, we showed that SalA-4 g promoted neuronal survival and inhibited neuronal apoptosis in primary hippocampal neurons exposed to oxygen and glucose deprivation (OGD) and in rats subjected to ischemia by transient middle cerebral artery occlusion (MCAO), respectively, and that SalA-4 g was more neuroprotective than salidroside. We further found that SalA-4 g elevated glucose uptake in OGD-injured primary hippocampal neurons and increased the expression and recruitment of glucose transporter 3 (GLUT3) in ischemic brain. Signaling analysis revealed that SalA-4 g triggered the phosphorylation of CREB, and increased the expression of PKA RII in primary hippocampal neurons exposed to OGD injury, while inhibition of PKA/CREB by H-89 alleviated the elevation in glucose uptake and GLUT3 expression, and blocked the protective effects of SalA-4 g. Moreover, SalA-4 g was noted to inhibit intracellular Ca 2+ influx and calpain1 activation in OGD-injured primary hippocampal neurons. Our results suggest that SalA-4 g neuroprotection might be mediated by increased glucose uptake and elevated GLUT3 expression through calpain1/PKA/CREB pathway. - Highlights: • A salidroside (Sal) analog (SalA-4 g) is prepared to be more neuroprotective than Sal. • SalA-4 g protected hippocampal neurons from oxygen and glucose deprivation insult. • SalA-4 g reduced ischemic injury after transient middle cerebral artery occlusion in rats. • Neuroprotection of SalA-4 g was mediated by GLUT3 level via calpain/PKA/CREB pathway

  7. Alteration of endothelial proteoglycan and heparanase gene expression by high glucose, insulin and heparin.

    Science.gov (United States)

    Han, J; Hiebert, L M

    2013-01-01

    Heparan sulfate proteoglycans (HSPGs) contain a core protein with glycosaminoglycans attached. Reduced glycosaminoglycan, in endothelial HSPGs syndecan and perlecan, is associated with diabetic cardiovascular complications but changes in core protein remain controversial. Since heparanase degrades heparan sulfate, we wished to determine if changes in endothelial heparanase mRNA, by high glucose (HG), correlate with changes in syndecan and perlecan core proteins, and to observe effects of heparin or insulin. RNA was isolated from cultured human aortic endothelial cells treated with HG (30mM), insulin (0.01 units/mL), heparin (0.5μg/mL), HG plus heparin and/or insulin for 24h. Real time PCR revealed that HG alone significantly increased heparanase, decreased syndecan with no effect on perlecan mRNA. Heparin or insulin significantly prevented the increase in heparanase but decreased perlecan mRNA while heparin, but not insulin, prevented the decrease in syndecan mRNA in HG treated cells. HG plus heparin and insulin increased heparanase and syndecan mRNA compared to all other treatments and decreased perlecan mRNA compared to control and HG alone. Heparin may protect endothelium from HG injury by reducing heparanase and increasing syndecan while insulin inhibits heparanase expression. Effects with insulin plus heparin suggest interference in transcriptional regulation of heparanase and syndecan genes. © 2013.

  8. Benefits and Harms of Sodium-Glucose Co-Transporter 2 Inhibitors in Patients with Type 2 Diabetes

    DEFF Research Database (Denmark)

    Storgaard, Heidi; Gluud, Lise L; Bennett, Cathy

    2016-01-01

    OBJECTIVE: Sodium-glucose co-transporter 2 inhibitors (SGLT2-i) are a novel drug class for the treatment of diabetes. We aimed at describing the maximal benefits and risks associated with SGLT2-i for patients with type 2 diabetes. DESIGN: Systematic review and meta-analysis. DATA SOURCES AND STUDY......, ketoacidosis and CVD. Secondary outcomes were fasting plasma glucose, body weight, blood pressure, heart rate, lipids, liver function tests, creatinine and adverse events including infections. The quality of the evidence was assessed using GRADE. RESULTS: Meta-analysis of 34 RCTs with 9,154 patients showed...... increased risk in non-serious adverse events. The analyses may overestimate the intervention benefit due bias....

  9. Improved ethanol production by engineered Saccharomyces cerevisiae expressing a mutated cellobiose transporter during simultaneous saccharification and fermentation.

    Science.gov (United States)

    Lee, Won-Heong; Jin, Yong-Su

    2017-03-10

    Although simultaneous saccharification and fermentation (SSF) of cellulosic biomass can offer efficient hydrolysis of cellulose through alleviating feed-back inhibition of cellulases by glucose, supplementation of β-glucosidase is necessary because most fermenting microorganisms cannot utilize cellobiose. Previously, we observed that SSF of cellulose by an engineered Saccharomyces cerevisiae expressing a cellobiose transporter (CDT-1) and an intracellular β-glucosidase (GH1-1) without β-glucosidase could not be performed as efficiently as the traditional SSF with extracellular β-glucosidase. However, we improved the ethanol production from SSF of cellulose by employing a further engineered S. cerevisiae expressing a mutant cellobiose transporter [CDT-1 (F213L) exhibiting higher V MAX than CDT-1] and GH1-1 in this study. Furthermore, limitation of cellobiose formation by reducing the amounts of cellulases mixture in SSF could lead the further engineered strain to produce ethanol considerably better than the parental strain with β-glucosidase. Probably, better production of ethanol by the further engineered strain seemed to be due to a higher affinity to cellobiose, which might be attributed to not only 2-times lower Monod constant (K S ) for cellobiose than K S of the parental strain for glucose but also 5-times lower K S than Michaelis-Menten constant (K M ) of the extracellular β-glucosidase for glucose. Our results suggest that modification of the cellobiose transporter in the engineered yeast to transport lower level of cellobiose enables a more efficient SSF for producing ethanol from cellulose. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Growth rate-regulated expression of the hexose transporter HXT5 in Saccharomyces cerevisiae

    NARCIS (Netherlands)

    Verwaal, René

    2003-01-01

    Glucose, which is the most preferred carbon source for the yeast Saccharomyces cerevisiae, is transported across the plasma membrane into cells by hexose transporter (Hxt) proteins. The Hxt proteins are encoded by a multigene family consisting of 20 members. It was shown previously that HXT1-4 and

  11. Glucose-induced repression of PPARalpha gene expression in pancreatic beta-cells involves PP2A activation and AMPK inactivation

    DEFF Research Database (Denmark)

    Ravnskjaer, Kim; Boergesen, Michael; Dalgaard, Louise T

    2006-01-01

    , the mechanism underlying this transcriptional repression by glucose remains unclear. Here we report that glucose-induced repression of PPARalpha gene expression in INS-1E cells is independent of beta-cell excitation and insulin secretion but requires activation of protein phosphatase 2A in a process involving...... but not AMPKalpha1 using RNAi suppressed PPARalpha expression, thereby mimicking the effect of glucose. These results indicate that activation of protein phosphatase 2A and subsequent inactivation of AMPK is necessary for glucose repression of PPARalpha expression in pancreatic beta-cells....... inactivation of the AMP-activated protein kinase (AMPK). Pharmacological activation of AMPK at high glucose concentrations interferes with glucose repression of PPARalpha and PPARalpha target genes in INS-1E cells as well as in rat islets. Specific knock-down of the catalytic AMPK-subunit AMPKalpha2...

  12. Transcription factor organic cation transporter 1 (OCT-1 affects the expression of porcine Klotho (KL gene

    Directory of Open Access Journals (Sweden)

    Yan Li

    2016-07-01

    Full Text Available Klotho (KL, originally discovered as an aging suppressor, is a membrane protein that shares sequence similarity with the β-glucosidase enzymes. Recent reports showed Klotho might play a role in adipocyte maturation and systemic glucose metabolism. However, little is known about the transcription factors involved in regulating the expression of porcine KL gene. Deletion fragment analysis identified KL-D2 (−418 bp to −3 bp as the porcine KL core promoter. MARC0022311SNP (A or G in KL intron 1 was detected in Landrace × DIV pigs using the Porcine SNP60 BeadChip. The pGL-D2-A and pGL-D2-G were constructed with KL-D2 and the intron fragment of different alleles and relative luciferase activity of pGL3-D2-G was significantly higher than that of pGL3-D2-A in the PK cells and ST cells. This was possibly the result of a change in KL binding ability with transcription factor organic cation transporter 1 (OCT-1, which was confirmed using electrophoretic mobility shift assays (EMSA and chromatin immune-precipitation (ChIP. Moreover, OCT-1 regulated endogenous KL expression by RNA interference experiments. Our study indicates SNP MARC0022311 affects porcine KL expression by regulating its promoter activity via OCT-1.

  13. Expression pattern of glucose metabolism genes in relation to development rate of buffalo (Bubalus bubalis) oocytes and in vitro-produced embryos.

    Science.gov (United States)

    Kumar, Parveen; Rajput, Sandeep; Verma, Arpana; De, Sachinandan; Datta, Tirtha Kumar

    2013-11-01

    The expression pattern of glucose metabolism genes (hexokinase, phosphofructokinase, glucose-6-phosphate dehydrogenase [G6PDH], lactate dehydrogenase [LDH], and pyruvate dehydrogenase [PDH]) were studied in buffalo in vitro-matured oocytes and in vitro-produced embryos cultured under different glucose concentrations (0 mM, 1.5 mM, 5.6 mM, and 10 mM) during in vitro maturation of oocytes and culture of IVF produced embryos. The expression of the genes varied significantly over the cleavage stages under different glucose concentrations. Developmental rate of embryos was highest under a constant glucose level (5.6 mM) throughout during maturation of oocytes and embryo culture. Expression pattern of glucose metabolism genes under optimum glucose level (5.6 mM) indicated that glycolysis is the major pathway of glucose metabolism during oocyte maturation and early embryonic stages (pre-maternal to zygotic transition [MZT]) and shifts to oxidative phosphorylation during post-MZT stages in buffalo embryos. Higher glucose level (10 mM) caused abrupt changes in gene expression and resulted in shifting toward anaerobic metabolism of glucose during post-MZT stages. This resulted in decreased development rate of embryos during post-MZT stages. High expression of LDH and PDH in the control groups (0 mM glucose) indicated that in absence of glucose, embryos try to use available pyruvate and lactate sources, but succumb to handle the post-MZT energy requirement, resulting to poor development rate. Expression pattern of G6PDH during oocyte maturation as well early embryonic development was found predictive of quality and development competence of oocytes/ embryos. Copyright © 2013 Elsevier Inc. All rights reserved.

  14. FoxO1 regulates myocardial glucose oxidation rates via transcriptional control of pyruvate dehydrogenase kinase 4 expression.

    Science.gov (United States)

    Gopal, Keshav; Saleme, Bruno; Al Batran, Rami; Aburasayn, Hanin; Eshreif, Amina; Ho, Kim L; Ma, Wayne K; Almutairi, Malak; Eaton, Farah; Gandhi, Manoj; Park, Edwards A; Sutendra, Gopinath; Ussher, John R

    2017-09-01

    Pyruvate dehydrogenase (PDH) is the rate-limiting enzyme for glucose oxidation and a critical regulator of metabolic flexibility during the fasting to feeding transition. PDH is regulated via both PDH kinases (PDHK) and PDH phosphatases, which phosphorylate/inactivate and dephosphorylate/activate PDH, respectively. Our goal was to determine whether the transcription factor forkhead box O1 (FoxO1) regulates PDH activity and glucose oxidation in the heart via increasing the expression of Pdk4 , the gene encoding PDHK4. To address this question, we differentiated H9c2 myoblasts into cardiac myocytes and modulated FoxO1 activity, after which Pdk4 /PDHK4 expression and PDH phosphorylation/activity were assessed. We assessed binding of FoxO1 to the Pdk4 promoter in cardiac myocytes in conjunction with measuring the role of FoxO1 on glucose oxidation in the isolated working heart. Both pharmacological (1 µM AS1842856) and genetic (siRNA mediated) inhibition of FoxO1 decreased Pdk4 /PDHK4 expression and subsequent PDH phosphorylation in H9c2 cardiac myocytes, whereas 10 µM dexamethasone-induced Pdk4 /PDHK4 expression was abolished via pretreatment with 1 µM AS1842856. Furthermore, transfection of H9c2 cardiac myocytes with a vector expressing FoxO1 increased luciferase activity driven by a Pdk4 promoter construct containing the FoxO1 DNA-binding element region, but not in a Pdk4 promoter construct lacking this region. Finally, AS1842856 treatment in fasted mice enhanced glucose oxidation rates during aerobic isolated working heart perfusions. Taken together, FoxO1 directly regulates Pdk4 transcription in the heart, thereby controlling PDH activity and subsequent glucose oxidation rates. NEW & NOTEWORTHY Although studies have shown an association between FoxO1 activity and pyruvate dehydrogenase kinase 4 expression, our study demonstrated that pyruvate dehydrogenase kinase 4 is a direct transcriptional target of FoxO1 (but not FoxO3/FoxO4) in the heart. Furthermore, we

  15. Oxygen-glucose deprivation regulates BACE1 expression through induction of autophagy in Neuro-2a/APP695 cells

    Directory of Open Access Journals (Sweden)

    Rong-fu Chen

    2015-01-01

    Full Text Available Our previous findings have demonstrated that autophagy regulation can alleviate the decline of learning and memory by eliminating deposition of extracellular beta-amyloid peptide (Aβ in the brain after stroke, but the exact mechanism is unclear. It is presumed that the regulation of beta-site APP-cleaving enzyme 1 (BACE1, the rate-limiting enzyme in metabolism of Aβ, would be a key site. Neuro-2a/amyloid precursor protein 695 (APP695 cell models of cerebral ischemia were established by oxygen-glucose deprivation to investigate the effects of Rapamycin (an autophagy inducer or 3-methyladenine (an autophagy inhibitor on the expression of BACE1. Either oxygen-glucose deprivation or Rapamycin down-regulated the expression of BACE1 while 3-methyladenine up-regulated BACE1 expression. These results confirm that oxygen-glucose deprivation down-regulates BACE1 expression in Neuro-2a/APP695 cells through the introduction of autophagy.

  16. TLQP-21 protects human umbilical vein endothelial cells against high-glucose-induced apoptosis by increasing G6PD expression.

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    Full Text Available Hyperglycemia causes oxidative stress that could damage vascular endothelial cells, leading to cardiovascular complications. The Vgf gene was identified as a nerve growth factor-responsive gene, and its protein product, VGF, is characterized by the presence of partially cleaved products. One of the VGF-derived peptides is TLQP-21, which is composed of 21 amino acids (residues 556-576. Past studies have reported that TLQP-21 could stimulate insulin secretion in pancreatic cells and protect these cells from apoptosis, which suggests that TLQP-21 has a potential function in diabetes therapy. Here, we explore the protective role of TLQP-21 against the high glucose-mediated injury of vascular endothelial cells. Using human umbilical vascular endothelial cells (HUVECs, we demonstrated that TLQP-21 (10 or 50 nM dose-dependently prevented apoptosis under high-glucose (30 mmol/L conditions (the normal glucose concentration is 5.6 mmol/L. TLQP-21 enhanced the expression of NAPDH, resulting in upregulation of glutathione (GSH and a reduction in the levels of reactive oxygen species (ROS. TLQP-21 also upregulated the expression of glucose-6-phosphate dehydrogenase (G6PD, which is known as the main source of NADPH. Knockdown of G6PD almost completely blocked the increase of NADPH induced by TLQP-21, indicating that TLQP-21 functions mainly through G6PD to promote NADPH generation. In conclusion, TLQP-21 could increase G6PD expression, which in turn may increase the synthesis of NADPH and GSH, thereby partially restoring the redox status of vascular endothelial cells under high glucose injury. We propose that TLQP-21 is a promising drug for diabetes therapy.

  17. Effects of dietary glucose and sodium chloride on intestinal glucose absorption of common carp (Cyprinus carpio L.).

    Science.gov (United States)

    Qin, Chaobin; Yang, Liping; Zheng, Wenjia; Yan, Xiao; Lu, Ronghua; Xie, Dizhi; Nie, Guoxing

    2018-01-08

    The co-transport of sodium and glucose is the first step for intestinal glucose absorption. Dietary glucose and sodium chloride (NaCl) may facilitate this physiological process in common carp (Cyprinus carpio L.). To test this hypothesis, we first investigated the feeding rhythm of intestinal glucose absorption. Carps were fed to satiety once a day (09:00 a.m.) for 1 month. Intestinal samples were collected at 01:00, 05:00, 09:00, 13:00, 17:00 and 21:00. Result showed that food intake greatly enhanced sodium/glucose cotransporter 1 (SGLT1) and glucose transporter type 2 (GLUT2) expressions, and improved glucose absorption, with highest levels at 09:00 a.m.. Then we designed iso-nitrogenous and iso-energetic diets with graded levels of glucose (10%, 20%, 30%, 40% and 50%) and NaCl (0%, 1%, 3% and 5%), and submitted to feeding trial for 10 weeks. The expressions of SGLT1 and GLUT2, brush border membrane vesicles (BBMVs) glucose transport and intestinal villus height were determined after the feeding trial. Increasing levels of dietary glucose and NaCl up-regulated mRNA and protein levels of SGLT1 and GLUT2, enhanced BBMVs glucose transport in the proximal, mid and distal intestine. As for histological adaptive response, however, high-glucose diet prolonged while high-NaCl diet shrank intestinal villus height. Furthermore, we also found that higher mRNA levels of SGLT1 and GLUT2, higher glucose transport capacity of BBMVs, and higher intestinal villus were detected in the proximal and mid intestine, compared to the distal part. Taken together, our study indicated that intestinal glucose absorption in carp was primarily occurred in the proximal and mid intestine, and increasing levels of dietary glucose and NaCl enhanced intestinal glucose absorption in carp. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. The PI3K/Akt Signaling Pathway Mediates the High Glucose-Induced Expression of Extracellular Matrix Molecules in Human Retinal Pigment Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Dong Qin

    2015-01-01

    Full Text Available Prolonged hyperglycemia is an important risk factor of the pathogenesis of diabetic retinopathy (DR. Extracellular matrix molecules, such as fibronectin, collagen IV, and laminin, are associated with fibrotic membranes. In this study, we investigated the expression of fibronectin, collagen IV, and laminin in RPE cells under high glucose conditions. Furthermore, we also detected the phosphorylation of protein kinase B (Akt under high glucose conditions in RPE cells. Our results showed that high glucose upregulated fibronectin, collagen IV, and laminin expression, and activated Akt in RPE cells. We also found that pretreatment with LY294002 (an inhibitor of phosphatidylinositol 3-kinase abolished high glucose-induced expression of fibronectin, collagen IV, and laminin in RPE cells. Thus, high glucose induced the expression of fibronectin, collagen IV, and laminin through PI3K/Akt signaling pathway in RPE cells, and the PI3K/Akt signaling pathway may contribute to the formation of fibrotic membrane during the development of DR.

  19. Effect of alpha interferon on glucose and alanine transport by rat renal brush border membrane vesicles

    International Nuclear Information System (INIS)

    Batuman, V.; Chadha, I.

    1990-01-01

    To investigate the pathogenetic mechanisms of interferon nephrotoxicity, we studied the effect of recombinant interferon alfa-2b on the uptake of 14 C-D-glucose and 14 C-L-alanine by rat renal brush-border-membrane vesicles. Interferon significantly inhibited 20 sec. sodium-dependent and 5 and 10 min. equilibrium uptake of both glucose and alanine. The inhibitory effect was dose dependent with maximum effect achieved at interferon concentration of 5 x 10 -8 M in the uptake media. The half-maximal inhibitory concentrations, IC 50 , of interferon on glucose uptake was 1.8 x 10 -8 M, and 5.4 x 10 -9 M on alanine uptake. Dixon plot analysis of uptake data was consistent with pure non-competitive inhibition. The inhibition constants, K i , 1.5 x 10 -8 M for glucose uptake, and 7.3 x 10 -9 M for alanine uptake, derived from Dixon plots were in close agreement with the IC 50 s calculated from the semilog dose response curves. These observations reveal that direct interactions at the proximal tubule cell membrane are involved in the pathogenesis of interferon nephrotoxicity, and that its mechanism of nephrotoxicity is similar to that of other low molecular weight proteins

  20. Dysregulation of the Glutamine Transporter Slc38a3 (SNAT3 and Ammoniagenic Enzymes in Obese, Glucose-Intolerant Mice

    Directory of Open Access Journals (Sweden)

    Stephanie M. Busque

    2014-08-01

    Full Text Available Background/Aims: Uric acid nephrolithiasis is prevalent among patients with type 2 diabetes and metabolic syndrome; it is correlated with an acidic urine and lower urinary ammonium excretion and is likely associated with insulin resistance. Insulin stimulates ammoniagenesis in renal cell lines via increased phosphate-dependent glutaminase (PDG activity and glutamine metabolism. Ammonium excretion into the proximal tubule is mediated at least in part by the Na+/H+-exchanger NHE3 and in the collecting duct involving the Rhesus protein RhCG. Here we tested, whether obesity and insulin resistance in a diet-induced mouse model could contribute to deranged ammonium excretion. Methods: Obesity was induced by diet in mice and the impact on key molecules of proximal tubular ammoniagenesis and urinary acid excretion tested. Results: Diet-induced obesity was confirmed by pathological intraperitoneal glucose tolerance tests (IPGTT. Three groups of mice were compared: control mice; obese, glucose-intolerant with abnormal IPGTT (O-GI; or moderate weight with normal IPGTT (Non-Responders, NR. Basal urinary ammonium excretion did not differ among groups. However, acid loading increased urinary ammonium excretion in all groups, but to a lesser extent in the O-GI group. SNAT3 mRNA expression was enhanced in both obese groups. PDG expression was elevated only in acid-loaded O-GI mice, whereas PEPCK was enhanced in both O-GI and NR groups given NH4CI. NHE activity in the brush border membrane of the proximal tubule was strongly reduced in the O-GI group whereas RhCG expression was similar. Conclusion: In sum, obesity and glucose intolerance impairs renal ammonium excretion in response to NH4CI feeding most likely through reduced NHE activity. The stimulation of SNAT3 and ammoniagenic enzyme expression may be compensatory but futile.

  1. ¿Cómo se transporta la glucosa a través de la membrana celular? How is glucose transported through cell membrane?

    Directory of Open Access Journals (Sweden)

    Diana Patricia Díaz Hernández

    2002-03-01

    Full Text Available La glucosa es el principal sustrato energético de la célula y para su ingreso requiere una proteína transportadora en la membrana celular. Se han descrito dos sistemas de transporte de glucosa y de otros monosacáridos: los transportadores de sodio y glucosa llamados SGLT ( sodium-glucose transporters y los transportadores de glucosa llamados GLUT ( glucosa transporters. En este artículo se presenta una revisión de las principales características moleculares, bioquímicas y funcionales de los transportadores de monosacáridos que se han descrito hasta el momento. Glucose is the main energy supply for the cell and requires a transport protein to enter through cell membranes. Two monosacharid transport systems have been described: SGLT (sodium-glucose transporters and GLUT (glucose transporters. In this article we review the main molecular, biochemical and functional characteristics of these monosacharid transporters.

  2. Chia (Salvia hispanica L.) enhances HSP, PGC-1α expressions and improves glucose tolerance in diet-induced obese rats.

    Science.gov (United States)

    Marineli, Rafaela da Silva; Moura, Carolina Soares; Moraes, Érica Aguiar; Lenquiste, Sabrina Alves; Lollo, Pablo Christiano Barboza; Morato, Priscila Neder; Amaya-Farfan, Jaime; Maróstica, Mário Roberto

    2015-05-01

    The aim of this study was to investigate the effects of chia seed and chia oil on heat shock protein (HSP) and related parameters in diet-induced obese rats. Animals were divided in six groups: control, high-fat and high-fructose diet (HFF), and HFF with chia seed or chia oil in short (6-wk) and long (12-wk) treatments. Plasma indicators of glucose tolerance and liver damage, skeletal muscle expression of antioxidant enzymes, and proteins controlling oxidative energy metabolism were determined. The limit of significance was set at P chia seed or chia oil did not reduce body weight gain or abdominal fat accumulation. However, chia seed and chia oil in both treatments improved glucose and insulin tolerance. Chia oil in both treatments induced expression of HSP70 and HSP25 in skeletal muscle. Short treatment with chia seed increased expression of HSP70, but not HSP25. Chia oil in both treatments restored superoxide dismutase and glutathione peroxidase expression. Extended treatment with chia seed and short treatment with chia oil restored peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α) expression. Chia oil restored the antioxidant system and induced the expression of a higher number of proteins than chia seed. The present study demonstrated new properties and molecular mechanisms associated with the beneficial effects of chia seed and chia oil consumption in diet-induced obese rats. Copyright © 2015 Elsevier Inc. All rights reserved.

  3. Chronic Hippocampal Expression of Notch Intracellular Domain Induces Vascular Thickening, Reduces Glucose Availability, and Exacerbates Spatial Memory Deficits in a Rat Model of Early Alzheimer.

    Science.gov (United States)

    Galeano, Pablo; Leal, María C; Ferrari, Carina C; Dalmasso, María C; Martino Adami, Pamela V; Farías, María I; Casabona, Juan C; Puntel, Mariana; Do Carmo, Sonia; Smal, Clara; Arán, Martín; Castaño, Eduardo M; Pitossi, Fernando J; Cuello, A Claudio; Morelli, Laura

    2018-03-26

    The specific roles of Notch in progressive adulthood neurodegenerative disorders have begun to be unraveled in recent years. A number of independent studies have shown significant increases of Notch expression in brains from patients at later stages of sporadic Alzheimer's disease (AD). However, the impact of Notch canonical signaling activation in the pathophysiology of AD is still elusive. To further investigate this issue, 2-month-old wild-type (WT) and hemizygous McGill-R-Thy1-APP rats (Tg(+/-)) were injected in CA1 with lentiviral particles (LVP) expressing the transcriptionally active fragment of Notch, known as Notch Intracellular Domain (NICD), (LVP-NICD), or control lentivirus particles (LVP-C). The Tg(+/-) rat model captures presymptomatic aspects of the AD pathology, including intraneuronal amyloid beta (Aβ) accumulation and early cognitive deficits. Seven months after LVP administration, Morris water maze test was performed, and brains isolated for biochemical and histological analysis. Our results showed a learning impairment and a worsening of spatial memory in LVP-NICD- as compared to LVP-C-injected Tg(+/-) rats. In addition, immuno histochemistry, ELISA multiplex, Western blot, RT-qPCR, and 1 H-NMR spectrometry of cerebrospinal fluid (CSF) indicated that chronic expression of NICD promoted hippocampal vessel thickening with accumulation of Aβ in brain microvasculature, alteration of blood-brain barrier (BBB) permeability, and a decrease of CSF glucose levels. These findings suggest that, in the presence of early Aβ pathology, expression of NICD may contribute to the development of microvascular abnormalities, altering glucose transport at the BBB with impact on early decline of spatial learning and memory.

  4. Regulation of glucose transporter protein-1 and vascular endothelial growth factor by hypoxia inducible factor 1α under hypoxic conditions in Hep-2 human cells.

    Science.gov (United States)

    Xu, Ou; Li, Xiaoming; Qu, Yongtao; Liu, Shuang; An, Jie; Wang, Maoxin; Sun, Qingjia; Zhang, Wen; Lu, Xiuying; Pi, Lihong; Zhang, Min; Shen, Yupeng

    2012-12-01

    The present study evaluated the regulation of glucose transporter protein-1 (Glut-1) and vascular endothelial growth factor (VEGF) by hypoxia inducible factor 1α (HIF-1α) under hypoxic conditions in Hep-2 human cells to explore the feasibility of these three genes as tumor markers. Hep-2 cells were cultured under hypoxic and normoxic conditions for 6, 12, 24, 36 and 48 h. The proliferation of Hep-2 cells was evaluated using an MTT assay. The protein and mRNA expression levels of HIF-1α, Glut-1 and VEGF were detected using the S-P immunocytochemical method, western blotting and reverse transcription polymerase chain reaction (RT-PCR). The results revealed that the expression levels of HIF-1α, Glut-1 and VEGF protein in Hep-2 cells were significantly elevated under hypoxic conditions compared with those under normoxic conditions over 36 h. Under hypoxic conditions, mRNA levels of HIF-1α were stable, while mRNA levels of Glut-1 and VEGF changed over time. In conclusion, Glut-1 and VEGF were upregulated by HIF-1α under hypoxic conditions in a time-dependent manner in Hep-2 cells and their co-expression serves as a tumor marker.

  5. Glucose 6P binds and activates HlyIIR to repress Bacillus cereus haemolysin hlyII gene expression.

    Directory of Open Access Journals (Sweden)

    Elisabeth Guillemet

    Full Text Available Bacillus cereus is a Gram-positive spore-forming bacterium causing food poisoning and serious opportunistic infections. These infections are characterized by bacterial accumulation despite the recruitment of phagocytic cells. We have previously shown that B. cereus Haemolysin II (HlyII induces macrophage cell death by apoptosis. In this work, we investigated the regulation of the hlyII gene. We show that HlyIIR, the negative regulator of hlyII expression in B. cereus, is especially active during the early bacterial growth phase. We demonstrate that glucose 6P directly binds to HlyIIR and enhances its activity at a post-transcriptional level. Glucose 6P activates HlyIIR, increasing its capacity to bind to its DNA-box located upstream of the hlyII gene, inhibiting its expression. Thus, hlyII expression is modulated by the availability of glucose. As HlyII induces haemocyte and macrophage death, two cell types that play a role in the sequestration of nutrients upon infection, HlyII may induce host cell death to allow the bacteria to gain access to carbon sources that are essential components for bacterial growth.

  6. Studies of gene expression and activity of hexokinase, phosphofructokinase and glycogen synthase in human skeletal muscle in states of altered insulin-stimulated glucose metabolism

    DEFF Research Database (Denmark)

    Vestergaard, H

    1999-01-01

    When whole body insulin-stimulated glucose disposal rate is measured in man applying the euglycaemic, hyperinsulinaemic clamp technique it has been shown that approximately 75% of glucose is taken up by skeletal muscle. After the initial transport step, glucose is rapidly phosphorylated to glucose...... due to an increased glycogen synthesis rate in muscle, which is paralleled by an increased total GS activity, increased GS mRNA levels and enhanced insulin-stimulated activation of GS. These changes are probably due to local contraction-dependent mechanisms. Likewise, one-legged exercise training has...

  7. Insulin signalling and glucose transport in the ovary and ovarian function during the ovarian cycle

    Science.gov (United States)

    Dupont, Joëlle; Scaramuzzi, Rex J.

    2016-01-01

    Data derived principally from peripheral tissues (fat, muscle and liver) show that insulin signals via diverse interconnecting intracellular pathways and that some of the major intersecting points (known as critical nodes) are the IRSs (insulin receptor substrates), PI3K (phosphoinositide kinase)/Akt and MAPK (mitogen-activated protein kinase). Most of these insulin pathways are probably also active in the ovary and their ability to interact with each other and also with follicle-stimulating hormone (FSH) and luteinizing hormone (LH) signalling pathways enables insulin to exert direct modulating influences on ovarian function. The present paper reviews the intracellular actions of insulin and the uptake of glucose by ovarian tissues (granulosa, theca and oocyte) during the oestrous/menstrual cycle of some rodent, primate and ruminant species. Insulin signals through diverse pathways and these are discussed with specific reference to follicular cell types (granulosa, theca and oocyte). The signalling pathways for FSH in granulosa cells and LH in granulosa and theca cells are summarized. The roles of glucose and of insulin-mediated uptake of glucose in folliculogenesis are discussed. It is suggested that glucose in addition to its well-established role of providing energy for cellular function may also have insulin-mediated signalling functions in ovarian cells, involving AMPK (AMP-dependent protein kinase) and/or hexosamine. Potential interactions of insulin signalling with FSH or LH signalling at critical nodes are identified and the available evidence for such interactions in ovarian cells is discussed. Finally the action of the insulin-sensitizing drugs metformin and the thiazolidinedione rosiglitazone on follicular cells is reviewed. PMID:27234585

  8. Increased Placental Glucose Transport Rates in Pregnant Mice Carrying Fetuses with Targeted Disruption of Their Placental-Specific Igf2 Transcripts Are Not Associated with Raised Circulating Glucose Concentrations

    Directory of Open Access Journals (Sweden)

    Clive J. Petry

    2011-01-01

    Full Text Available At the beginning of the third week of pregnancy, mouse fetuses with targeted disruption of their paternally-transmitted insulin-like growth factor 2 gene placental-specific transcripts have growth-restricted placentas but normal body weights due to upregulated placental nutrient transport. We assessed whether increased placental glucose transport rates were associated with raised maternal glucose concentrations by performing intraperitoneal glucose tolerance tests (ipGTT in pregnant mice carrying knockout pups and comparing them with mice carrying genotype-matched phenotypically wild type pups. Mean ± SD body weights of affected pups were 95 ± 8% of control values at e16 and 73 ± 7% at e18. There were no differences in areas under the maternal ipGTT curves at either e16 (mean ± SD being 99.0 ± 9.1% of control values; P=.9 or e18 (91.4 ± 13.4%; P=.3, suggesting that effects on transplacental glucose transport in these mice are not mediated through changes in maternal glucose concentrations.

  9. Difference in transient ischemia-induced neuronal damage and glucose transporter-1 immunoreactivity in the hippocampus between adult and young gerbils

    Directory of Open Access Journals (Sweden)

    Seung Min Park

    2016-05-01

    Full Text Available Objective(s: The alteration of glucose transporters is closely related with the pathogenesis of brain edema. We compared neuronal damage/death in the hippocampus between adult and young gerbils following transient cerebral ischemia/reperfusion and changes of glucose transporter-1(GLUT-1-immunoreactive microvessels in their ischemic hippocampal CA1 region. Materials and Methods: Transient cerebral ischemia was developed by 5-min occlusion of both common carotid arteries. Neuronal damage was examined by cresyl violet staining, NeuN immunohistochemistry and Fluoro-Jade B histofluorescence staining and changes in GLUT-1 expression was carried out by immunohistochemistry. Results: About 90% of pyramidal neurons only in the adult CA1 region were damaged after ischemia/reperfusion; in the young, about 53 % of pyramidal neurons were damaged from 7 days after ischemia/reperfusion. The density of GLUT-1-immunoreactive microvessels was significantly higher in the young sham-group than that in the adult sham-group. In the ischemia-operated-groups, the density of GLUT-1-immunoreactive microvessels was significantly decreased in the adult and young at 1 and 4 days post-ischemia, respectively, thereafter, the density of GLUT-1-immunoreactive microvessels was gradually increased in both groups after ischemia/reperfusion. Conclusion: CA1 pyramidal neurons of the young gerbil were damaged much later than that in the adult and that GLUT-1-immunoreactive microvessels were significantly decreased later in the young. These data indicate that GLUT-1 might differently contribute to neuronal damage according to age after ischemic insults.

  10. Blood-Brain Glucose Transfer in Alzheimer's disease

    DEFF Research Database (Denmark)

    Gejl, Michael; Brock, Birgitte; Egefjord, Lærke

    2017-01-01

    There are fewer than normal glucose transporters at the blood-brain barrier (BBB) in Alzheimer's disease (AD). When reduced expression of transporters aggravates the symptoms of AD, the transporters become a potential target of therapy. The incretin hormone GLP-1 prevents the decline of cerebral...... metabolic rate for glucose (CMRglc) in AD, and GLP-1 may serve to raise transporter numbers. We hypothesized that the GLP-1 analog liraglutide would prevent the decline of CMRglc in AD by raising blood-brain glucose transfer, depending on the duration of disease. We randomized 38 patients with AD...

  11. The expression of genes involved in glucose metabolism is affected by N-methyl-D-aspartate receptor antagonism: a putative link between metabolism and an animal model of psychosis.

    Science.gov (United States)

    Iasevoli, Felice; Latte, Gianmarco; Avvisati, Livia; Sarappa, Chiara; Aloj, Luigi; de Bartolomeis, Andrea

    2012-09-01

    Psychosis has been associated with glucose metabolism impairment. Here, we explored the gene expression of hexokinase 1 (Hk1) and glucose transporter 3 (GLUT3) after the administration of a subanesthetic or a subconvulsant dose of ketamine in rats, considered to provide an animal model of psychosis. Indeed, Hk1 and GLUT3 are crucially involved in the glucose utilization in brain tissues and have also been implicated in the pathophysiology of psychosis. Quantitative brain imaging of transcripts was used to evaluate Hk1 and GLUT3 mRNA in rat brain regions related to ketamine-induced behavioral abnormalities. Hk1 transcript was significantly increased by 50 mg/kg ketamine in cortical and subcortical areas, whereas 12 mg/kg ketamine affected Hk1 expression in the auditory cortex only. GLUT3 expression was increased by 12 mg/kg ketamine in the frontal cortex and decreased by 50 mg/kg ketamine in subcortical areas. The results show that Hk1 and GLUT3 are extensively and differentially affected by ketamine dose, supporting the view that glucose metabolism and psychosis may be causally related and suggesting that these molecules may play a role in the pathophysiology of ketamine-induced behavioral abnormalities. Copyright © 2012 Wiley Periodicals, Inc.

  12. Effects of methyl mercury on the activity and gene expression of mouse Langerhans islets and glucose metabolism.

    Science.gov (United States)

    Maqbool, Faheem; Bahadar, Haji; Niaz, Kamal; Baeeri, Maryam; Rahimifard, Mahban; Navaei-Nigjeh, Mona; Ghasemi-Niri, Seyedeh Farnaz; Abdollahi, Mohammad

    2016-07-01

    Mercury (Hg) is a well-known heavy metal and causes various toxic effects. It is abundantly present in fish in the form of methyl mercury (MeHg). Also, various other forms of mercury can enter human body either from environment like inhalation or through dental amalgams. The present study was designed to assess MeHg induced toxicity in mouse plasma and pancreatic islets with respect to insulin secretion, oxidative balance, glucose tolerance, gene expression, caspases 3 and 9 activities. MeHg was dissolved in tap water and administered at doses 2.5, 5 and 10 mg/kg/day, for 4 weeks. In mice, MeHg significantly caused increase in plasma insulin as well as C-peptides. Glucose intolerance, insulin resistance and hyperglycemia are main consequences of our study that correlate with the gene expression changes of glucose homeostasis as well. MeHg caused increase lipid peroxidation in a dose-dependent manner in plasma as well as pancreatic islets. In addition, total thiol molecules and ferrous reducing antioxidant power in MeHg treated group was decreased in plasma as well as pancreatic islets. Caspases 3 and 9 activities of pancreatic islets were upregulated in MeHg exposed animals. Reactive oxygen species were extremely high in pancreatic islets of MeHg treated groups. MeHg disrupted gluconeogenesis/glycogenolysis pathways and insulin secretory functions of islets by targeting GDH, GLUT2 and GCK genes of pancreatic islets. In conclusion, the current study revealed that insulin pathways, oxidative balance and glucose metabolism encoded genetic makeup are susceptible to MeHg toxicity and the subsequent oxidative stress and alternations in gene expression could lead toward functional abnormalities in other organs. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Suppression of glucose-6-phosphate-isomerase induced arthritis by oral administration of transgenic rice seeds expressing altered peptide ligands of glucose-6-phosphate-isomerase.

    Science.gov (United States)

    Hirota, Tomoya; Tsuboi, Hiroto; Iizuka-Koga, Mana; Takahashi, Hiroyuki; Asashima, Hiromitsu; Yokosawa, Masahiro; Kondo, Yuya; Ohta, Masaru; Wakasa, Yuhya; Matsumoto, Isao; Takaiwa, Fumio; Sumida, Takayuki

    2017-05-01

    To investigate the effects of transgenic rice seeds expressing the altered peptide ligand (APL) of human glucose-6-phosphate-isomerase (hGPI 325-339 ) in mice model of GPI-induced arthritis (GIA). We generated transgenic rice expressing T-cell epitope of hGPI 325-339 and APL12 contained in the seed endosperm. The transgenic rice seeds were orally administered prophylactically before the induction of GIA. The severity of arthritis and titers of serum anti-GPI antibodies were evaluated. We examined for IL-17 production in splenocytes and inguinal lymph node (iLN) cells, and analyzed the expression levels of functional molecules in splenocytes. Prophylactic treatment of GIA mice with APL12 transgenic (APL12-TG) rice seeds significantly reduced the severity of arthritis and titers of serum anti-GPI antibodies compared with non-transgenic (Non-TG) rice-treated mice. APL12-TG and hGPI 325-339 transgenic (hGPI 325-339 -TG) rice seeds improved the histopathological arthritis scores and decreased IL-17 production compared with non-TG rice-treated mice. APL12-TG rice-treated GIA mice showed upregulation of Foxp3 and GITR protein in CD4  +  CD25  +  Foxp3 +  cells in the spleen compared with non-TG rice- and hGPI 325-339 -TG rice-treated mice. APL12-TG rice seeds improved the severity of GIA through a decrease in production of IL-17 and anti-GPI antibodies via upregulation of Foxp3 and GITR expression on Treg cells in spleen.

  14. A crosstalk between Na⁺ channels, Na⁺/K⁺ pump and mitochondrial Na⁺ transporters controls glucose-dependent cytosolic and mitochondrial Na⁺ signals.

    Science.gov (United States)

    Nita, Iulia I; Hershfinkel, Michal; Lewis, Eli C; Sekler, Israel

    2015-02-01

    Glucose-dependent cytosolic Na(+) influx in pancreatic islet β cells is mediated by TTX-sensitive Na(+) channels and is propagated into the mitochondria through the mitochondrial Na(+)/Ca(2+) exchanger, NCLX. Mitochondrial Na(+) transients are also controlled by the mitochondrial Na(+)/H(+) exchanger, NHE, while cytosolic Na(+) changes are governed by Na(+)/K(+) ATPase pump. The functional interaction between the Na(+) channels, Na(+)/K(+) ATPase pump and mitochondrial Na(+) transporters, NCLX and NHE, in mediating Na(+) signaling is poorly understood. Here, we combine fluorescent Na(+) imaging, pharmacological inhibition by TTX, ouabain and EIPA, with molecular control of NCLX expression, so as to investigate the crosstalk between Na(+) transporters on both the plasma membrane and the mitochondria. According to our results, glucose-dependent cytosolic Na(+) response was enhanced by ouabain and was followed by a rise in mitochondrial Na(+) signal. Silencing of NCLX expression using siNCLX, did not affect the glucose- or ouabain-dependent cytosolic rise in Na(+). In contrast, the ouabain-dependent rise in mitochondrial Na(+) was strongly suppressed by siNCLX. Furthermore, mitochondrial Na(+) influx rates were accelerated in cells treated with the Na(+)/H(+) exchanger inhibitor, EIPA or by combination of EIPA and ouabain. Similarly, TTX blocked the cytosolic and mitochondrial Na(+) responses, which were enhanced by ouabain or EIPA, respectively. Our results suggest that Na(+)/K(+) ATPase pump controls cytosolic glucose-dependent Na(+) rise, in a manner that is mediated by TTX-sensitive Na(+) channels and subsequent mitochondrial Na(+) uptake via NCLX. Furthermore, these results indicate that mitochondrial Na(+) influx via NCLX is antagonized by Na(+) efflux, which is mediated by the mitochondrial NHE; thus, the duration of mitochondrial Na(+) transients is set by the interplay between these pivotal transporters. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Metformin + Sodium-glucose Co-transporter-2 Inhibitor: Salutogenic Lifestyle Mimetics in a Tablet?

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2018-01-01

    Full Text Available Salutogenesis is an accepted approach for chronic disease management. Calorie restriction and exercise are two evidence based salutogenic interventions in diabetes treatment. Calorie restriction mimetics and exercise mimetics may be used as pharmacological tools to help manage diabetes in a sulutogenic manner. This article discusses the biochemical basis and pharmacology of metformin and sodium glucose cotransporter 2 inhibitors. It describes how a combination of these drugs can be used as a calories restriction and exercise mimetic, to help improve diabetes control.

  16. A role for polyamines in glucose-stimulated insulin-gene expression.

    Science.gov (United States)

    Welsh, N

    1990-01-01

    The aim of the present study was to evaluate the possible role for polyamines in the glucose regulation of the metabolism of insulin mRNA of pancreatic islet cells. For this purpose islets were prepared from adult mice and cultured for 2 days in culture medium RPMI 1640 containing 3.3 mM- or 16.7 mM-glucose with or without the addition of the inhibitors of polyamine biosynthesis difluoromethylornithine (DFMO) and ethylglyoxal bis(guanylhydrazone) (EGBG). Culture at the high glucose concentration increased the islet contents of both insulin mRNA and polyamines. The synthesis of total RNA, total islet polyamines and polyamines associated with islet nuclei was also increased. When the combination of DFMO and EGBG was added in the presence of 16.7 mM-glucose, low contents of insulin mRNA, spermine and spermidine were observed. Total islet polyamine synthesis was also depressed by DFMO + EGBG, unlike islet biosynthesis of polyamines associated with nuclei, which was not equally decreased by the polyamine-synthesis inhibitors. Total RNA synthesis and turnover was not affected by DFMO + EGBG. Finally, actinomycin D attenuated the glucose-induced enhancement of insulin mRNA, and cycloheximide counteracted the insulin-mRNA attenuation induced by inhibition of polyamine synthesis. It is concluded that the glucose-induced increase in insulin mRNA is paralleled by increased contents and rates of polyamine biosynthesis and that an attenuation of the increase in polyamines prevents the increase in insulin mRNA. In addition, the results are compatible with the view that polyamines exert their effects on insulin mRNA mainly by increasing the stability of this messenger. PMID:2241922

  17. The Effects of Insulin and Glucose on Different Characteristics of a UPEC: Alterations in Growth Rate and Expression Levels of some Virulence Genes.

    Science.gov (United States)

    Gumus, Defne; Yoruk, Emre; Kalayci-Yuksek, Fatma; Uz, Gulsen; Topal-Sarikaya, Aysegul; Ang-Kucuker, Mine

    2017-10-01

    Host factors are known to modulate virulence, antibiotic susceptibility, and growth rate of bacteria. The effect of human insulin and glucose on growth rate and expression of virulence genes (usp, sfa/foc, cnf1) of a uropathogenic E. coli (UPEC) strain were investigated in this study. E. coli C7 was grown in tryptic soy broth (TSB-control) and TSB containing 20 µU/mL insulin, 200 µU/mL insulin, 0.1% glucose, and 200 µU/mL insulin + 0.1% glucose. Growth rates were determined via optical density measurement in a spectrophotometer. Real-time polymerase chain reaction was used to determine the gene expression levels. Statistical analyses were performed via Tukey's post hoc-test. Differences were found to be not statistically significant for bacterial growth rate in TSB and TSB with insulin and/or glucose. The expression levels of all three virulence genes were shown to be reduced significantly in the presence of insulin and/or glucose. The highest degree of repression was observed in 200 µU/mL insulin added to TSB. Also, the repression level of the gene expression was revealed to be reduced in 0.1% glucose supplemented TSB. In the present study, it was shown that insulin and glucose can modulate UPEC's gene expression while the growth rate was not affected.

  18. Blood-Brain Glucose Transfer in Alzheimer's disease

    DEFF Research Database (Denmark)

    Gejl, Michael; Brock, Birgitte; Egefjord, Lærke

    2017-01-01

    There are fewer than normal glucose transporters at the blood-brain barrier (BBB) in Alzheimer's disease (AD). When reduced expression of transporters aggravates the symptoms of AD, the transporters become a potential target of therapy. The incretin hormone GLP-1 prevents the decline of cerebral...

  19. The ontogeny of nutrient transporter and digestive enzyme gene expression in domestic pigeon (Columba livia) intestine and yolk sac membrane during pre- and posthatch development.

    Science.gov (United States)

    Dong, X Y; Wang, Y M; Yuan, C; Zou, X T

    2012-08-01

    To better understand the digestive capacity in domestic pigeons (Columba livia), this study was conducted to evaluate nutrient transporters and digestive enzymes gene expression in small intestine and yolk sac membrane (YSM) during pre- and posthatch development. We investigated the oligopeptide transporter Pept1, sodium glucose transporter SGLT1, glucose transporter GLUT2, aminopeptidase-N (APN), and sucrase-isomaltase (SI). Intestine was collected at embryo d 12, 14, and 16, day of hatch, and d 1, 3, 5, 8, and 14 posthatch. The YSM was collected at embryo d 12, 14, 16, and day of hatch. The cDNA fragments for Pept1, SGLT1, GLUT2, APN, and SI were isolated and cloned using reverse-transcription PCR. The sequences data showed that these genes were highly identical to the gene of chicken. The mRNA expression of each gene was assayed using real-time PCR. Expression of intestinal nutrient transporters increased linearly (Ppigeons and establish a foundation for future research on the nutrients requirements for young pigeons.

  20. Assessment of the antidiabetic potential of selected medicinal plants using in vitro bioassays of muscle glucose transport and liver glucose production

    DEFF Research Database (Denmark)

    Beidokhti, M N; Sanchez Villavicencio, M L; Eid, H M

    2016-01-01

    Type 2 diabetes mellitus (T2DM) is the most common type of diabetes mellitus. It is caused by decreased insulin sensitivity in target organs like liver, muscle and adipose tissue, and/or a deficiency in insulin secretion. In T2DM, increased hepatic glucose output and decreased glucose uptake by s...

  1. Induction of amino acid transporters expression by endurance exercise in rat skeletal muscle

    International Nuclear Information System (INIS)

    Murakami, Taro; Yoshinaga, Mariko

    2013-01-01

    Highlights: •Regulation of amino acid transporter expression in working muscle remains unclear. •Expression of amino acid transporters for leucine were induced by a bout of exercise. •Requirement of leucine in muscle cells might regulate expression of its transporters. •This information is beneficial for understanding the muscle remodeling by exercise. -- Abstract: We here investigated whether an acute bout of endurance exercise would induce the expression of amino acid transporters that regulate leucine transport across plasma and lysosomal membranes in rat skeletal muscle. Rats ran on a motor-driven treadmill at a speed of 28 m/min for 90 min. Immediately after the exercise, we observed that expression of mRNAs encoding L-type amino acid transporter 1 (LAT1) and CD98 was induced in the gastrocnemius, soleus, and extensor digitorum longus (EDL) muscles. Sodium-coupled neutral amino acid transporter 2 (SNAT2) mRNA was also induced by the exercise in those three muscles. Expression of proton-assisted amino acid transporter 1 (PAT1) mRNA was slightly but not significantly induced by a single bout of exercise in soleus and EDL muscles. Exercise-induced mRNA expression of these amino acid transporters appeared to be attenuated by repeated bouts of the exercise. These results suggested that the expression of amino acid transporters for leucine may be induced in response to an increase in the requirement for this amino acid in the cells of working skeletal muscles

  2. Induction of amino acid transporters expression by endurance exercise in rat skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Murakami, Taro, E-mail: tamuraka@sgk.ac.jp; Yoshinaga, Mariko

    2013-10-04

    Highlights: •Regulation of amino acid transporter expression in working muscle remains unclear. •Expression of amino acid transporters for leucine were induced by a bout of exercise. •Requirement of leucine in muscle cells might regulate expression of its transporters. •This information is beneficial for understanding the muscle remodeling by exercise. -- Abstract: We here investigated whether an acute bout of endurance exercise would induce the expression of amino acid transporters that regulate leucine transport across plasma and lysosomal membranes in rat skeletal muscle. Rats ran on a motor-driven treadmill at a speed of 28 m/min for 90 min. Immediately after the exercise, we observed that expression of mRNAs encoding L-type amino acid transporter 1 (LAT1) and CD98 was induced in the gastrocnemius, soleus, and extensor digitorum longus (EDL) muscles. Sodium-coupled neutral amino acid transporter 2 (SNAT2) mRNA was also induced by the exercise in those three muscles. Expression of proton-assisted amino acid transporter 1 (PAT1) mRNA was slightly but not significantly induced by a single bout of exercise in soleus and EDL muscles. Exercise-induced mRNA expression of these amino acid transporters appeared to be attenuated by repeated bouts of the exercise. These results suggested that the expression of amino acid transporters for leucine may be induced in response to an increase in the requirement for this amino acid in the cells of working skeletal muscles.

  3. Exposure of ELF-EMF and RF-EMF Increase the Rate of Glucose Transport and TCA Cycle in Budding Yeast.

    Science.gov (United States)

    Lin, Kang-Wei; Yang, Chuan-Jun; Lian, Hui-Yong; Cai, Peng

    2016-01-01

    In this study, we investigated the transcriptional response to 50 Hz extremely low frequency electromagnetic field (ELF-EMF) and 2.0 GHz radio frequency electromagnetic field (RF-EMF) exposure by Illumina sequencing technology using budding yeast as the model organism. The transcription levels of 28 genes were upregulated and those of four genes were downregulated under ELF-EMF exposure, while the transcription levels of 29 genes were upregulated and those of 24 genes were downregulated under RF-EMF exposure. After validation by reverse transcription quantitative polymerase chain reaction (RT-qPCR), a concordant direction of change both in differential gene expression (DGE) and RT-qPCR was demonstrated for nine genes under ELF-EMF exposure and for 10 genes under RF-EMF exposure. The RT-qPCR results revealed that ELF-EMF and RF-EMF exposure can upregulate the expression of genes involved in glucose transportation and the tricarboxylic acid (TCA) cycle, but not the glycolysis pathway. Energy metabolism is closely related with the cell response to environmental stress including EMF exposure. Our findings may throw light on the mechanism underlying the biological effects of EMF.

  4. Perinatal and early postnatal changes in the expression of monocarboxylate transporters MCT1 and MCT2 in the rat forebrain.

    Science.gov (United States)

    Baud, Olivier; Fayol, Laurence; Gressens, Pierre; Pellerin, Luc; Magistretti, Pierre; Evrard, Philippe; Verney, Catherine

    2003-10-20

    In addition to glucose, monocarboxylates including lactate represent a major source of energy for the brain, especially during development. We studied the immunocytochemical expression of the monocarboxylate transporters MCT1 and MCT2 in the rat brain between embryonic day (E) 16 and postnatal day (P) 14. At E16-18, MCT1-like immunoreactivity was found throughout the cortical anlage, being particularly marked medially in the hippocampal anlage next to the ventricle. In a complementary pattern, MCT2-like immunoreactivity was expressed along the medial and ventral border of the ventricle in the medial septum and habenula before birth. The hypothalamic area exhibited MCT2 and MCT1 positive areas from E18 on. These transient labelings revealed four main sites of monocarboxylate and/or glucose exchange: the brain parenchyma, the epithelial cells, the ependymocytes, and the glia limitans. During the first postnatal week, MCT1 immunoreactivity extended massively to the vessel walls and moderately to the developing astrocytes in the cortex. In contrast, MCT2 immunoreactivity was faint in blood vessels but massive in developing astrocytes from P3 to P7. Neither MCT2 nor MCT1 colocalized with neuronal, microglial, or oligodendrocytic markers during the first postnatal week. At P14, a part of the scattered punctate MCT2 staining could be associated with astrocytes and postsynaptic dendritic labeling. The transient pattern of expression of MCTs throughout the perinatal period suggests a potential relationship with the maturation of the blood-brain barrier. Copyright 2003 Wiley-Liss, Inc.

  5. Acute activation of GLP-1-expressing neurons promotes glucose homeostasis and insulin sensitivity

    Science.gov (United States)

    Glucagon-like peptides are co-released from enteroendocrine L cells in the gut and preproglucagon (PPG) neurons in the Brainstem. PPG-derived GLP-1/2 are probably key neuroendocrine signals for the control of energy balance and glucose Homeostasis. The objective of this study was to determine whethe...

  6. Cloning and expression trait of UDP-glucose:flavonoid 3-O ...

    African Journals Online (AJOL)

    glucose:flavonoid 3-O-glucosyltransferase (UF3GT) is a committed catalytic enzyme in the late stage of anthocyanin biosynthesis. BrUF3GT1 and BrUF3GT2 genes were cloned by reverse transcription polymerase chain reaction (RT-PCR) method ...

  7. Dynamical modeling of liver Aquaporin-9 expression and glycerol permeability in hepatic glucose metabolism.

    Science.gov (United States)

    Gena, Patrizia; Buono, Nicoletta Del; D'Abbicco, Marcello; Mastrodonato, Maria; Berardi, Marco; Svelto, Maria; Lopez, Luciano; Calamita, Giuseppe

    2017-01-01

    Liver is crucial in the homeostasis of glycerol, an important metabolic intermediate. Plasma glycerol is imported by hepatocytes mainly through Aquaporin-9 (AQP9), an aquaglyceroporin channel negatively regulated by insulin in rodents. AQP9 is of critical importance in glycerol metabolism since hepatic glycerol utilization is rate-limited at the hepatocyte membrane permeation step. Glycerol kinase catalyzes the initial step for the conversion of the imported glycerol into glycerol-3-phosphate, a major substrate for de novo synthesis of glucose (gluconeogenesis) and/or triacyglycerols (lipogenesis). A model addressing the glucose-insulin system to describe the hepatic glycerol import and metabolism and the correlation with the glucose homeostasis is lacking so far. Here we consider a system of first-order ordinary differential equations delineating the relevance of hepatocyte AQP9 in liver glycerol permeability. Assuming the hepatic glycerol permeability as depending on the protein levels of AQP9, a mathematical function is designed describing the time course of the involvement of AQP9 in mouse hepatic glycerol metabolism in different nutritional states. The resulting theoretical relationship is derived fitting experimental data obtained with murine models at the fed, fasted or re-fed condition. While providing useful insights into the dynamics of liver AQP9 involvement in male rodent glycerol homeostasis our model may be adapted to the human liver serving as an important module of a whole body-model of the glucose metabolism both in health and metabolic diseases. Copyright © 2016 Elsevier GmbH. All rights reserved.

  8. Safety of Sodium-Glucose Co-Transporter 2 Inhibitors during Ramadan Fasting: Evidence, Perceptions and Guidelines

    Directory of Open Access Journals (Sweden)

    Salem A. Beshyah

    2016-06-01

    Full Text Available Sodium-glucose co-transporter 2 (SGLT2 inhibitors are a new glucose-lowering therapy for T2DM with documented benefits on blood glucose, hypertension, weight reduction and long term cardiovascular benefit. They have an inherent osmotic diuretic effect and lead to some volume loss and possible dehydration. There is some concern about the safety of using SGLT2 inhibitors in Muslim type 2 diabetes mellitus (T2DM patients during the fast during Ramadan. Currently, there is a dearth of research data to help guide physicians and reassure patients.  One study confirmed good glycemic control with less risk of hypoglycemia and no marked volume depletion. Data in the elderly and in combination with diuretics are reassuring of their safe to use in Ramadan in general. SGLT2 inhibitor-related diabetic ketoacidosis has not been reported during Ramadan and is unlikely to be relevant. Survey of physicians revealed that the majority felt that SGLT2 inhibitors are generally safe in T2DM patients during Ramadan fasting but should be discontinued in certain high risk patients. Some professional groups with interest in diabetes and Ramadan fasting included SGLT2 inhibitors in their guidelines on management of diabetes during Ramadan. They acknowledged the lack of trial data, recommended caution in high risk groups, advised regular monitoring and emphasized pre-Ramadan patients’ education. In conclusion, currently, knowledge, data and experience with SGLT2 inhibitors in Ramadan are limited. Nonetheless, stable patients with normal kidney function and low risk of dehydration may safely use the SGLT2 inhibitors therapy. Higher risk patients should be observed carefully and managed on individual basis.

  9. Chlorogenic acid stimulates glucose transport in skeletal muscle via AMPK activation: a contributor to the beneficial effects of coffee on diabetes.

    Directory of Open Access Journals (Sweden)

    Khang Wei Ong

    Full Text Available Chlorogenic acid (CGA has been shown to delay intestinal glucose absorption and inhibit gluconeogenesis. Our aim was to investigate the role of CGA in the regulation of glucose transport in skeletal muscle isolated from db/db mice and L6 skeletal muscle cells. Oral glucose tolerance test was performed on db/db mice treated with CGA and soleus muscle was isolated for 2-deoxyglucose transport study. 2DG transport was also examined in L6 myotubes with or without inhibitors such as wortmannin or compound c. AMPK was knocked down with AMPKα1/2 siRNA to study its effect on CGA-stimulated glucose transport. GLUT 4 translocation, phosphorylation of AMPK and Akt, AMPK activity, and association of IRS-1 and PI3K were investigated in the presence of CGA. In db/db mice, a significant decrease in fasting blood sugar was observed 10 minutes after the intraperitoneal administration of 250 mg/kg CGA and the effect persisted for another 30 minutes after the glucose challenge. Besides, CGA stimulated and enhanced both basal and insulin-mediated 2DG transports in soleus muscle. In L6 myotubes, CGA caused a dose- and time-dependent increase in glucose transport. Compound c and AMPKα1/2 siRNA abrogated the CGA-stimulated glucose transport. Consistent with these results, CGA was found to phosphorylate AMPK and ACC, consistent with the result of increased AMPK activities. CGA did not appear to enhance association of IRS-1 with p85. However, we observed activation of Akt by CGA. These parallel activations in turn increased translocation of GLUT 4 to plasma membrane. At 2 mmol/l, CGA did not cause any significant changes in viability or proliferation of L6 myotubes. Our data demonstrated for the first time that CGA stimulates glucose transport in skeletal muscle via the activation of AMPK. It appears that CGA may contribute to the beneficial effects of coffee on Type 2 diabetes mellitus.

  10. Effect of Ganoderma lucidum spores intervention on glucose and lipid metabolism gene expression profiles in type 2 diabetic rats.

    Science.gov (United States)

    Wang, Fang; Zhou, Zhongkai; Ren, Xiaochong; Wang, Yuyang; Yang, Rui; Luo, Jinhua; Strappe, Padraig

    2015-05-22

    The fruiting body of Ganoderma lucidum has been used as a traditional herbal medicine for many years. However, to the date, there is no detailed study for describing the effect of G. lucidum spores on oxidative stress, blood glucose level and lipid compositions in animal models of type 2 diabetic rats, in particular the effect on the gene expression profiles associated with glucose and lipid metabolisms. G. lucidum spores powder (GLSP) with a shell-broken rate >99.9 % was used. Adult male Sprague-Dawley rats were randomly divided into three groups (n = 8/group). Group 1: Normal control, normal rats with ordinary feed; Group 2: Model control, diabetic rats with ordinary feed without intervention; Group 3: GLSP, diabetic rats with ordinary feed, an intervention group utilizing GLSP of 1 g per day by oral gavages for 4 consecutive weeks. Type 2 diabetic rats were obtained by streptozocin (STZ) injection. The changes in the levels of glucose, triglycerides, total cholesterol and HDL-cholesterol in blood samples were analyzed after GLSP intervention. Meanwhile, gene expressions associated with the possible molecular mechanism of GLSP regulation were also investigated using a quantitative RT-PCR. The reduction of blood glucose level occurred within the first 2 weeks of GLSP intervention and the lipid synthesis in the diabetic rats of GLSP group was significantly decreased at 4 weeks compared to the model control group. Furthermore, it was also found that GLSP intervention greatly attenuated the level of oxidative stress in the diabetic rats. Quantitative RT-PCR analysis showed up-regulation of lipid metabolism related genes (Acox1, ACC, Insig-1 and Insig-2) and glycogen synthesis related genes (GS2 and GYG1) in GLSP group compared to model control group. Additionally, there were no significant changes in the expression of other genes, such as SREBP-1, Acly, Fas, Fads1, Gpam, Dgat1, PEPCK and G6PC1. This study might indicate that GLSP consumption could provide a

  11. Mechanism of inhibition of human glucose transporter GLUT1 is conserved between cytochalasin B and phenylalanine amides

    Science.gov (United States)

    Kapoor, Khyati; Finer-Moore, Janet S.; Pedersen, Bjørn P.; Caboni, Laura; Waight, Andrew; Hillig, Roman C.; Bringmann, Peter; Heisler, Iring; Müller, Thomas; Siebeneicher, Holger; Stroud, Robert M.

    2016-01-01

    Cancerous cells have an acutely increased demand for energy, leading to increased levels of human glucose transporter 1 (hGLUT1). This up-regulation suggests hGLUT1 as a target for therapeutic inhibitors addressing a multitude of cancer types. Here, we present three inhibitor-bound, inward-open structures of WT-hGLUT1 crystallized with three different inhibitors: cytochalasin B, a nine-membered bicyclic ring fused to a 14-membered macrocycle, which has been described extensively in the literature of hGLUTs, and two previously undescribed Phe amide-derived inhibitors. Despite very different chemical backbones, all three compounds bind in the central cavity of the inward-open state of hGLUT1, and all binding sites overlap the glucose-binding site. The inhibitory action of the compounds was determined for hGLUT family members, hGLUT1–4, using cell-based assays, and compared with homology models for these hGLUT members. This comparison uncovered a probable basis for the observed differences in inhibition between family members. We pinpoint regions of the hGLUT proteins that can be targeted to achieve isoform selectivity, and show that these same regions are used for inhibitors with very distinct structural backbones. The inhibitor cocomplex structures of hGLUT1 provide an important structural insight for the design of more selective inhibitors for hGLUTs and hGLUT1 in particular. PMID:27078104

  12. Risk stratification of patients with diabetes and the role of sodium glucose co-transporter inhibitors 2 during Ramadan fasting.

    Science.gov (United States)

    Adnan, Zaina

    2017-09-01

    The month of Ramadan represents a golden opportunity for better management of patients with diabetes not only during Ramadan month, but also through the entire year. Pre Ramadan period is crucial for evaluating and preparing patients with diabetes intending to Fast Ramadan. The risk stratification categories should take into consideration patients with diabetes having specific conditions such as nephrotic syndrome who are predisposed to thrombosis independent to their estimated glomerular filtration rate and glycated haemoglobin. Furthermore, population-specific conditions such as nomadic Bedouins living in remote areas should be considered as part of the very high risk category for fasting Ramadan. Published data regarding the use of sodium glucose co-transporter 2 inhibitors during Ramadan is very limited. Dapagliflozin was the only agent studied during Ramadan. Therefore, it is suggested to categorize this group of agents differently from other agents such as metformin and incretin based therapy studied vastly during Ramadan. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Orexin-A stimulates the expression of GLUT4 in a glucose dependent manner in the liver of orange-spotted grouper (Epinephelus coioides).

    Science.gov (United States)

    Zhang, Cong; Sun, Caiyun; Wang, Bin; Yan, Peipei; Wu, Amin; Yang, Guokun; Li, Wensheng

    2016-09-01

    Orexins are hypothalamic neuropeptides involved in the central regulation of feeding behavior, sleep-wake cycle and other physiological functions. Orexin-A can regulate energy metabolism and increase glucose uptake, suggesting a role in glucose metabolism. In this study, we investigated the effects of orexin-A on GLUT4 mRNA and protein levels and the intracellular signaling mechanisms mediating orexin-A activity in the hepatocytes of grouper. Our results demonstrate that intraperitoneal injection of orexin-A increased the expression of GLUT4 in the liver, and this effect was significantly enhanced by co-injection of glucose. Treatment of primary cultured hepatocytes with either orexin-A or glucose alone had no effect on the expression of GLUT4, while co-treatment with orexin-A and glucose significantly increased the expression of GLUT4. This stimulatory effect was partially blocked by inhibitors to ERK1/2, JNK or p38 MAPK and was further blocked by an orexin receptor antagonist, which indicates that orexin-A could stimulate the expression of GLUT4 in a glucose dependent manner in primary hepatocytes via ERK1/2, JNK and p38 signaling. Our results suggest that orexin-A could play a pivotal role in stimulating glucose utilization in grouper, for a long-term goal, which might be useful in reducing costs in the aquaculture industry. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. Glucose and insulin modify thrombospondin 1 expression and secretion in primary adipocytes from diet-induced obese rats.

    Science.gov (United States)

    Garcia-Diaz, Diego F; Arellano, Arianna V; Milagro, Fermin I; Moreno-Aliaga, Maria Jesus; Portillo, Maria Puy; Martinez, J Alfredo; Campion, Javier

    2011-09-01

    Thrombospondin 1 (TSP-1), an antiangiogenic factor and transforming growth factor (TGF)-β activity regulator, has been recently recognized as an adipokine that correlates with obesity, inflammation and insulin resistance processes. In the present study, epididymal adipocytes of rats that were fed a chow or a high-fat diet (HFD) for 50 days were isolated and incubated (24-72 h) in low (5.6 mM) or high (HG; 25 mM) glucose, in the presence or absence of 1.6 nM insulin. Rats fed the HF diet showed an established obesity state. Serum TSP-1 levels and TSP-1 mRNA basal expression of adipocytes from HFD rats were higher than those from controls. Adipocytes from HFD animals presented an insulin resistance state, as suggested by the lower insulin-stimulated glucose uptake as compared to controls. TSP-1 expression in culture was higher in adipocytes from obese animals at 24 h, but when the adipocytes were treated with HG, these expression levels dropped dramatically. Later at 72 h, TSP-1 expression was lower in adipocytes from HFD rats, and no effects of the other treatments were observed. Surprisingly, the secretion levels of this protein at 72 h were increased significantly by the HG treatment in both types of adipocytes, although they were even higher in adipocytes from obese animals. Finally, cell viability was significantly reduced by HG treatment in both types of adipocytes. In summary, TSP-1 expression/secretion was modulated in an in vitro model of insulin-resistant adipocytes. The difference between expression and secretion patterns suggests a posttranscriptional regulation. The present study confirms that TPS-1 is closely associated with obesity-related mechanisms.

  15. Immuno-localization of glucose transporter 4 in healthy human gingiva

    Directory of Open Access Journals (Sweden)

    Suresh Ranga Rao

    2012-01-01

    Conclusion: This may be the first study to demonstrate the expression of GLUT 4 in the healthy human gingiva. The results of this study raise the possibility that gingiva may serve as a target tissue for insulin action.

  16. Unaltered lactate and glucose transporter levels in the MPTP mouse model of Parkinson's disease

    DEFF Research Database (Denmark)

    Puchades, Maja; Sogn, Carl Johan; Maehlen, Jan

    2013-01-01

    been found. OBJECTIVES: We raise the question of whether changes in the amount transporters of energy substrates are involved in the pathogenesis of PD. METHODS: We have used confocal immunofluorescence and immunogold postembedding electron microscopic techniques to study whether there are altered...

  17. Glucose Transport in Cultured Animal Cells: An Exercise for the Undergraduate Cell Biology Laboratory

    Science.gov (United States)

    Ledbetter, Mary Lee S.; Lippert, Malcolm J.

    2002-01-01

    Membrane transport is a fundamental concept that undergraduate students of cell biology understand better with laboratory experience. Formal teaching exercises commonly used to illustrate this concept are unbiological, qualitative, or intricate and time consuming to prepare. We have developed an exercise that uses uptake of radiolabeled nutrient…

  18. Regulation of Glucose Transport in Quiescent, Lactating, and Neoplastic Mammary Epithelia.

    Science.gov (United States)

    1997-10-01

    transport into tumor cells might offer new therapeutic possibilities. In order to test these hypotheses, the following specific aims were chosen: 1...will also be studied in cells isolated from human milk(Lindquist, et al., 1994), and in cells isolated from reduction mammoplasty specimens. Dr

  19. Functional expression of Burkholderia cenocepacia xylose isomerase in yeast increases ethanol production from a glucose-xylose blend.

    Science.gov (United States)

    de Figueiredo Vilela, Leonardo; de Mello, Vinicius Mattos; Reis, Viviane Castelo Branco; Bon, Elba Pinto da Silva; Gonçalves Torres, Fernando Araripe; Neves, Bianca Cruz; Eleutherio, Elis Cristina Araújo

    2013-01-01

    This study presents results regarding the successful cloning of the bacterial xylose isomerase gene (xylA) of Burkholderia cenocepacia and its functional expression in Saccharomyces cerevisiae. The recombinant yeast showed to be competent to efficiently produce ethanol from both glucose and xylose, which are the main sugars in lignocellulosic hydrolysates. The heterologous expression of the gene xylA enabled a laboratorial yeast strain to ferment xylose anaerobically, improving ethanol production from a fermentation medium containing a glucose-xylose blend similar to that found in sugar cane bagasse hydrolysates. The insertion of xylA caused a 5-fold increase in xylose consumption, and over a 1.5-fold increase in ethanol production and yield, in comparison to that showed by the WT strain, in 24h fermentations, where it was not detected accumulation of xylitol. These findings are encouraging for further studies concerning the expression of B. cenocepacia xylA in an industrial yeast strain. Copyright © 2012 Elsevier Ltd. All rights reserved.

  20. Chia (salvia Hispanica L.) Enhances Hsp, Pgc-1 Alpha Expressions And Improves Glucose Tolerance In Diet-induced Obese Rats

    OpenAIRE

    Marineli; Rafaela da Silva; Moura; Carolina Soares; Moraes; Erica Aguiar; Lenquiste; Sabrina Alves; Barboza Lollo; Pablo Christiano; Morato; Priscila Neder; Amaya-Farfan; Jaime; Marostica; Mario Roberto; Jr.

    2016-01-01

    Objective: The aim of this study was to investigate the effects of chia seed and chia oil on heat shock protein (HSP) and related parameters in diet-induced obese rats. Methods: Animals were divided in six groups: control, high-fat and high-fructose diet (HFF), and HFF with chia seed or chia oil in short (6-wk) and long (12-wk) treatments. Plasma indicators of glucose tolerance and liver damage, skeletal muscle expression of antioxidant enzymes, and proteins controlling oxidative energy metab...

  1. Genome-Wide Function, Evolutionary Characterization and Expression Analysis of Sugar Transporter Family Genes in Pear (Pyrus bretschneideri Rehd).

    Science.gov (United States)

    Li, Jia-Ming; Zheng, Dan-man; Li, Lei-ting; Qiao, Xin; Wei, Shu-wei; Bai, Bin; Zhang, Shao-ling; Wu, Jun

    2015-09-01

    The sugar transporter (ST) plays an important role in plant growth, development and fruit quality. In this study, a total of 75 ST genes were identified in the pear (Pyrus bretschneideri Rehd) genome based on systematic analysis. Furthermore, all ST genes identified were grouped into eight subfamilies according to conserved domains and phylogenetic analysis. Analysis of cis-regulatory element sequences of all ST genes identified the MYBCOREATCYCB1 promoter in sucrose transporter (SUT) and monosaccharide transporter (MST) genes of pear, while in grape it is exclusively found in SUT subfamily members, indicating divergent transcriptional regulation in different species. Gene duplication event analysis indicated that whole-genome duplication (WGD) and segmental duplication play key roles in ST gene amplification, followed by tandem duplication. Estimation of positive selection at codon sites of ST paralog pairs indicated that all plastidic glucose translocator (pGlcT) subfamily members have evolved under positive selection. In addition, the evolutionary history of ST gene duplications indicated that the ST genes have experienced significant expansion in the whole ST gene family after the second WGD, especially after apple and pear divergence. According to the global RNA sequencing results of pear fruit development, gene expression profiling showed the expression of 53 STs. Combined with quantitative real-time PCR (qRT-PCR) analysis, two polyol/monosaccharide transporter (PLT) and three tonoplast monosaccharide transporter (tMT) members were identified as candidate genes, which may play important roles in sugar accumulation during pear fruit development and ripening. Identification of highly expressed STs in fruit is important for finding novel genes contributing to enhanced levels of sugar content in pear fruit. © The Author 2015. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For permissions, please

  2. Quantitative metabolomics of a xylose-utilizing Saccharomyces cerevisiae strain expressing the Bacteroides thetaiotaomicron xylose isomerase on glucose and xylose.

    Science.gov (United States)

    Mert, M J; Rose, S H; la Grange, D C; Bamba, T; Hasunuma, T; Kondo, A; van Zyl, W H

    2017-10-01

    The yeast Saccharomyces cerevisiae cannot utilize xylose, but the introduction of a xylose isomerase that functions well in yeast will help overcome the limitations of the fungal oxido-reductive pathway. In this study, a diploid S. cerevisiae S288c[2n YMX12] strain was constructed expressing the Bacteroides thetaiotaomicron xylA (XI) and the Scheffersomyces stipitis xyl3 (XK) and the changes in the metabolite pools monitored over time. Cultivation on xylose generally resulted in gradual changes in metabolite pool size over time, whereas more dramatic fluctuations were observed with cultivation on glucose due to the diauxic growth pattern. The low G6P and F1,6P levels observed with cultivation on xylose resulted in the incomplete activation of the Crabtree effect, whereas the high PEP levels is indicative of carbon starvation. The high UDP-D-glucose levels with cultivation on xylose indicated that the carbon was channeled toward biomass production. The adenylate and guanylate energy charges were tightly regulated by the cultures, while the catabolic and anabolic reduction charges fluctuated between metabolic states. This study helped elucidate the metabolite distribution that takes place under Crabtree-positive and Crabtree-negative conditions when cultivating S. cerevisiae on glucose and xylose, respectively.

  3. Cooperative roles of glucose and asparagine-linked glycosylation in T-type calcium channel expression

    Czech Academy of Sciences Publication Activity Database

    Lazniewska, Joanna; Rzhepetskyy, Yuriy; Zhang, F. X.; Zamponi, G. W.; Weiss, Norbert

    2016-01-01

    Roč. 468, 11/12 (2016), s. 1837-1851 ISSN 0031-6768 R&D Projects: GA ČR GA15-13556S; GA MŠk 7AMB15FR015 Institutional support: RVO:61388963 Keywords : calcium channel * T-type channel * Ca(v)3.2 * glucose * N-glycosylation * trafficking Subject RIV: CE - Biochemistry Impact factor: 3.156, year: 2016

  4. Psidium guajava Linn. leaf extract affects hepatic glucose transporter-2 to attenuate early onset of insulin resistance consequent to high fructose intake: An experimental study

    Science.gov (United States)

    Mathur, R.; Dutta, Shagun; Velpandian, T.; Mathur, S.R.

    2015-01-01

    Background: Insulin resistance (IR) is amalgam of pathologies like altered glucos metabolism, dyslipidemia, impaired glucose tolerance, non-alcoholic fatty liver disease, and associated with type-II diabetes and cardiometabolic diseases. One of the reasons leading to its increased and early incidence is understood to be a high intake of processed fructose containing foods and beverages by individuals, especially, during critical developmental years. Objective: To investigate the preventive potential of aqueous extract of Psidium guajava leaves (PG) against metabolic pathologies, vis-à-vis, IR, dyslipidemia, hyperleptinemia and hypertension, due to excess fructose intake initiated during developmental years. Materials and Methods: Post-weaning (4 weeks old) male rats were provided fructose (15%) as drinking solution, ad libitum, for 8 weeks and assessed for food and water/fructose intake, body weight, fasting blood sugar, mean arterial pressure, lipid biochemistry, endocrinal (insulin, leptin), histopathological (fatty liver) and immunohistochemical (hepatic glucose transporter [GLUT2]) parameters. Parallel treatment groups were administered PG in doses of 250 and 500 mg/kg/d, po × 8 weeks and assessed for same parameters. Using extensive liquid chromatography-mass spectrometry protocols, PG was analyzed for the presence of phytoconstituents like Myrecetin, Luteolin, Kaempferol and Guavanoic acid and validated to contain Quercetin up to 9.9%w/w. Results: High fructose intake raised circulating levels of insulin and leptin and hepatic GLUT2 expression to promote IR, dyslipidemia, and hypertension that were favorably re-set with PG. Although PG is known for its beneficial role in diabetes mellitus, for the first time we report its potential in the management of lifelong pathologies arising from high fructose intake initiated during developmental years. PMID:25829790

  5. Glucose Metabolism Gene Expression Patterns and Tumor Uptake of {sup 18}F-Fluorodeoxyglucose After Radiation Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, George D., E-mail: george.wilson@beaumont.edu [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan (United States); Beaumont BioBank, William Beaumont Hospital, Royal Oak, Michigan (United States); Thibodeau, Bryan J.; Fortier, Laura E.; Pruetz, Barbara L. [Beaumont BioBank, William Beaumont Hospital, Royal Oak, Michigan (United States); Galoforo, Sandra; Baschnagel, Andrew M.; Chunta, John [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan (United States); Oliver Wong, Ching Yee [Department of Diagnostic Radiology and Molecular Imaging Medicine, William Beaumont Hospital, Royal Oak, Michigan (United States); Yan, Di; Marples, Brian [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan (United States); Huang, Jiayi [Department of Radiation Oncology, William Beaumont Hospital, Royal Oak, Michigan (United States); Department of Radiation Oncology, Washington University School of Medicine, St. Louis, Missouri (United States)

    2014-11-01

    Purpose: To investigate whether radiation treatment influences the expression of glucose metabolism genes and compromises the potential use of {sup 18}F-fluorodeoxyglucose positron emission tomography (FDG-PET) as a tool to monitor the early response of head and neck cancer xenografts to radiation therapy (RT). Methods and Materials: Low passage head and neck squamous cancer cells (UT14) were injected to the flanks of female nu/nu mice to generate xenografts. After tumors reached a size of 500 mm{sup 3} they were treated with either sham RT or 15 Gy in 1 fraction. At different time points, days 3, 9, and 16 for controls and days 4, 7, 12, 21, 30, and 40 after irradiation, 2 to 3 mice were assessed with dynamic FDG-PET acquisition over 2 hours. Immediately after the FDG-PET the tumors were harvested for global gene expression analysis and immunohistochemical evaluation of GLUT1 and HK2. Different analytic parameters were used to process the dynamic PET data. Results: Radiation had no effect on key genes involved in FDG uptake and metabolism but did alter other genes in the HIF1α and glucose transport–related pathways. In contrast to the lack of effect on gene expression, changes in the protein expression patterns of the key genes GLUT1/SLC2A1 and HK2 were observed after radiation treatment. The changes in GLUT1 protein expression showed some correlation with dynamic FDG-PET parameters, such as the kinetic index. Conclusion: {sup 18}F-fluorodeoxyglucose positron emission tomography changes after RT would seem to represent an altered metabolic state and not a direct effect on the key genes regulating FDG uptake and metabolism.

  6. Molecular dynamics simulation studies of GLUT4: substrate-free and substrate-induced dynamics and ATP-mediated glucose transport inhibition.

    Directory of Open Access Journals (Sweden)

    Suma Mohan

    Full Text Available BACKGROUND: Glucose transporter 4 (GLUT4 is an insulin facilitated glucose transporter that plays an important role in maintaining blood glucose homeostasis. GLUT4 is sequestered into intracellular vesicles in unstimulated cells and translocated to the plasma membrane by various stimuli. Understanding the structural details of GLUT4 will provide insights into the mechanism of glucose transport and its regulation. To date, a crystal structure for GLUT4 is not available. However, earlier work from our laboratory proposed a well validated homology model for GLUT4 based on the experimental data available on GLUT1 and the crystal structure data obtained from the glycerol 3-phosphate transporter. METHODOLOGY/PRINCIPAL FINDINGS: In the present study, the dynamic behavior of GLUT4 in a membrane environment was analyzed using three forms of GLUT4 (apo, substrate and ATP-substrate bound states. Apo form simulation analysis revealed an extracellular open conformation of GLUT4 in the membrane favoring easy exofacial binding of substrate. Simulation studies with the substrate bound form proposed a stable state of GLUT4 with glucose, which can be a substrate-occluded state of the transporter. Principal component analysis suggested a clockwise movement for the domains in the apo form, whereas ATP substrate-bound form induced an anti-clockwise rotation. Simulation studies suggested distinct conformational changes for the GLUT4 domains in the ATP substrate-bound form and favor a constricted behavior for the transport channel. Various inter-domain hydrogen bonds and switching of a salt-bridge network from E345-R350-E409 to E345-R169-E409 contributed to this ATP-mediated channel constriction favoring substrate occlusion and prevention of its release into cytoplasm. These data are consistent with the biochemical studies, suggesting an inhibitory role for ATP in GLUT-mediated glucose transport. CONCLUSIONS/SIGNIFICANCE: In the absence of a crystal structure for any

  7. The zinc transporter ZNT3 co-localizes with insulin in INS-1E pancreatic beta cells and influences cell survival, insulin secretion capacity, and ZNT8 expression

    DEFF Research Database (Denmark)

    Smidt, Kamille; Larsen, Agnete; Brønden, Andreas

    2016-01-01

    Zinc trafficking in pancreatic beta cells is tightly regulated by zinc transporting (ZNTs) proteins. The role of different ZNTs in the beta cells is currently being clarified. ZNT8 transports zinc into insulin granules and is critical for a correct insulin crystallization and storage...... in the granules whereas ZNT3 knockout negatively affects beta cell function and survival. Here, we describe for the first time the sub-cellular localization of ZNT3 by immuno-gold electron microscopy and supplement previous data from knockout experiments with investigations of the effect of ZNT3 in a pancreatic...... beta cell line, INS-1E overexpressing ZNT3. In INS-1E cells, we found that ZNT3 was abundant in insulin containing granules located close to the plasma membrane. The level of ZNT8 mRNA was significantly decreased upon over-expression of ZNT3 at different glucose concentrations (5, 11 and 21 mM glucose...

  8. GLUT1 expression in malignant tumors and its use as an immunodiagnostic marker

    Directory of Open Access Journals (Sweden)

    Kátia C. Carvalho

    2011-01-01

    Full Text Available OBJECTIVE: To analyze glucose transporter 1 expression patterns in malignant tumors of various cell types and evaluate their diagnostic value by immunohistochemistry. INTRODUCTION: Glucose is the major source of energy for cells, and glucose transporter 1 is the most common glucose transporter in humans. Glucose transporter 1 is aberrantly expressed in several tumor types. Studies have implicated glucose transporter 1 expression as a prognostic and diagnostic marker in tumors, primarily in conjunction with positron emission tomography scan data. METHODS: Immunohistochemistry for glucose transporter 1 was performed in tissue microarray slides, comprising 1955 samples of malignant neoplasm from different cell types. RESULTS: Sarcomas, lymphomas, melanomas and hepatoblastomas did not express glucose transporter 1. Fortyseven per cent of prostate adenocarcinomas were positive, as were 29% of thyroid, 10% of gastric and 5% of breast adenocarcinomas. Thirty-six per cent of squamous cell carcinomas of the head and neck were positive, as were 42% of uterine cervix squamous cell carcinomas. Glioblastomas and retinoblastomas showed membranous glucose transporter 1 staining in 18.6% and 9.4% of all cases, respectively. Squamous cell carcinomas displayed membranous expression, whereas adenocarcinomas showed cytoplasmic glucose transporter 1 expression. CONCLUSION: Glucose transporter 1 showed variable expression in various tumor types. Its absence in sarcomas, melanomas, hepatoblastomas and lymphomas suggests that other glucose transporters mediate the glycolytic pathway in these tumors. The data suggest that glucose transporter 1 is a valuable immunohistochemical marker that can be used to identify patients for evaluation by positron emission tomography scan. The function of cytoplasmic glucose transporter 1 in adenocarcinomas must be further examined.

  9. L-Theanine Administration Modulates the Absorption of Dietary Nutrients and Expression of Transporters and Receptors in the Intestinal Mucosa of Rats

    Directory of Open Access Journals (Sweden)

    Qiongxian Yan

    2017-01-01

    Full Text Available L-theanine has various advantageous functions for human health; whether or not it could mediate the nutrients absorption is unknown yet. The effects of L-theanine on intestinal nutrients absorption were investigated using rats ingesting L-theanine solution (0, 50, 200, and 400 mg/kg body weight per day for two weeks. The decline of insulin secretion and glucose concentration in the serum was observed by L-theanine. Urea and high-density lipoprotein were also reduced by 50 mg/kg L-theanine. Jejunal and ileac basic amino acids transporters SLC7a1 and SLC7a9, neutral SLC1a5 and SLC16a10, and acidic SLC1a1 expression were upregulated. The expression of intestinal SGLT3 and GLUT5 responsible for carbohydrates uptake and GPR120 and FABP2 associated with fatty acids transport were inhibited. These results indicated that L-theanine could inhibit the glucose uptake by downregulating the related gene expression in the small intestine of rats. Intestinal gene expression of transporters responding to amino acids absorption was stimulated by L-theanine administration.

  10. Nitric oxide increases cyclic GMP levels, AMP-activated protein kinase (AMPK)alpha1-specific activity and glucose transport in human skeletal muscle

    DEFF Research Database (Denmark)

    Deshmukh, A S; Long, Y C; de Castro Barbosa, T

    2010-01-01

    an insulin-independent signalling mechanism. Consistent with this, spermine NONOate increased AMP-activated protein kinase (AMPK)-alpha1-associated activity (1.7-fold, p .... CONCLUSIONS/INTERPRETATION: Pharmacological treatment of skeletal muscle with spermine NONOate increases glucose transport via insulin-independent signalling pathways involving increased intracellular cGMP levels and AMPK-alpha1-associated activity....

  11. Disease resistance conferred by expression of a gene encoding H2O2-generating glucose oxidase in transgenic potato plants.

    Science.gov (United States)

    Wu, G; Shortt, B J; Lawrence, E B; Levine, E B; Fitzsimmons, K C; Shah, D M

    1995-09-01

    Plant defense responses to pathogen infection involve the production of active oxygen species, including hydrogen peroxide (H2O2). We obtained transgenic potato plants expressing a fungal gene encoding glucose oxidase, which generates H2O2 when glucose is oxidized. H2O2 levels were elevated in both leaf and tuber tissues of these plants. Transgenic potato tubers exhibited strong resistance to a bacterial soft rot disease caused by Erwinia carotovora subsp carotovora, and disease resistance was sustained under both aerobic and anaerobic conditions of bacterial infection. This resistance to soft rot was apparently mediated by elevated levels of H2O2, because the resistance could be counteracted by exogenously added H2O2-degrading catalase. The transgenic plants with increased levels of H2O2 also exhibited enhanced resistance to potato late blight caused by Phytophthora infestans. The development of lesions resulting from infection by P. infestans was significantly delayed in leaves of these plants. Thus, the expression of an active oxygen species-generating enzyme in transgenic plants represents a novel approach for engineering broad-spectrum disease resistance in plants.

  12. [Cloning of Escherichia coli K12 xylose isomerase (glucose isomerase) and studying the enzymatic properties of its expression product].

    Science.gov (United States)

    Rozanov, A S; Zagrebel'nyĭ, S N; Beklemishchev, A B

    2009-01-01

    The coding region of Escherichia coli K12 xylose (glucose) isomerase gene was inserted into the pRAC expression vector and cloned in E. coli BL21 (DE3) cells. After induction of expression of the cloned gene, the proportion of recombinant xylose isomerase accounted for 40% of the total protein content. As a result of one-stage purification by affinity chromatography, a protein preparation of 90% purity was obtained. The recombinant enzyme catalyzed the isomerization of glucose to fructose and exhibited maximum activity (0.8 U/mg) at 45 degrees C and pH 6.8. The enzyme required Mg2+ ions as a cofactor. When Mg2+ and Co2+ ions were simultaneously present in the reaction medium, the enzyme activity increased by 15-20%. Complete replacement of Mg2+ with Co2+ decreased the enzyme activity. In the presence of Ca2+ at concentrations comparable to the concentration of Mg2+, the enzyme was not inhibited, although published data reported inhibition of similar enzymes by Ca2+. The recombinant enzyme exhibited a very low thermostability: it underwent a slow inactivation when incubated at 45 degrees C and was completely inactivated after incubation at 65 degrees C for 1 h.

  13. Effect of lycium barbarum polysaccharides on high glucose-induced retinal ganglion cell apoptosis, gene expression and delayed rectifier potassium current

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    Xiao-Fei Ma

    2017-05-01

    Full Text Available Objective: To study the effect of lycium barbarum polysaccharides (LBP on high glucoseinduced retinal ganglion cell apoptosis, gene expression and delayed rectifier potassium current. Methods: RGC-5 retinal ganglion cell lines were cultured and divided into control group, high glucose group and LBP group that were treated with normal DMEM, highglucose DMEM as well as high-glucose DMEM containing 500 ng/mL LBP respectively. After treatment, the Annexin V-FITC/PI kits were used to measure the number of apoptotic cells, fluorescence quantitative PCR kits were used to determine the expression of apoptosis genes and antioxidant genes, and patch clamp was used to test delayed rectifier potassium current. Results: 12, 24, 36 and 48 h after intervention, the number of apoptotic cells of high glucose group was significantly higher than that of control group, and the number of apoptotic cells of LBP group was significantly lower than that of high glucose group (P<0.05; 24 and 48 h after intervention, c-fos, c-jun, caspase-3, caspase-9, Nrf-2, NQO1 and HO-1 mRNA expression as well as potassium current amplitude (IK and maximum conductance (Gmax of high glucose group were significantly higher than those of control group while half maximum activation voltage (V1/2 was significantly lower than that of control group (P<0.05; c-fos, c-jun, caspase-3 and caspase-9 mRNA expression as well as IK and Gmax of LBP group were significantly lower than those of high glucose group, while Nrf-2, NQO1 and HO-1 mRNA expression as well as V1/2 of LBP group were significantly higher than those of high glucose group (P<0.05. Conclusions: LBP can reduce the high glucose-induced retinal ganglion cell apoptosis and inhibit the delayed rectifier potassium current amplitude.

  14. Hepatic mRNA expression for genes related to somatotropic axis, glucose and lipid metabolisms, and inflammatory response of periparturient dairy cows treated with recombinant bovine somatotropin.

    Science.gov (United States)

    Silva, P R B; Weber, W J; Crooker, B A; Collier, R J; Thatcher, W W; Chebel, R C

    2017-05-01

    Objectives of this experiment were to evaluate the effects of recombinant bovine somatotropin (rbST) treatment of periparturient dairy cows on hepatic mRNA expression for genes related to the somatotropic axis, insulin, glucose, and lipid metabolism, inflammation, and oxidative stress. Holstein cows were enrolled in the experiment at 253 ± 3 d of gestation and assigned to 1 of 3 treatments: untreated control (n = 53), 87.5 mg of rbST (n = 56; rbST87.5), and 125 mg of rbST (n = 57; rbST125). Cows in the rbST87.5 and rbST125 treatments received weekly injections of rbST from -21 to 28 d relative to calving. A subsample of cows (control = 20, rbST87.5 = 20, rbST125 = 20) was randomly selected for collection of liver samples according to expected calving date, BCS, and previous lactation 305-d mature equivalent milk yield. Only cows that had liver sampled at -21 ± 3, -7 ± 3, and 7 ± 3 d relative to calving were used in the current experiment. Blood, sampled weekly from -28 to 21 d relative to calving, was used to determine the concentrations of growth hormone, insulin-like growth factor 1, insulin, cortisol, fatty acids, β-hydroxybutyrate, glucose, haptoglobin, and tumor necrosis factor-α. Liver samples were used to determine hepatic mRNA expression of 50 genes. Treatment with rbST increased growth hormone concentrations during the postpartum period (control = 9.0 ± 0.7, rbST87.5 = 15.3 ± 1.0, rbST125 = 18.5 ± 1.3 ng/mL) and increased insulin-like growth factor 1 concentrations during the prepartum period (control = 107.4 ± 7.2, rbST87.5 = 126.9 ± 6.6, rbST125 = 139.4 ± 6.9 ng/mL). Control cows had greater postpartum concentrations of β-hydroxybutyrate (control = 776.4 ± 64.0, rbST87.5 = 628.4 ± 59.7, rbST125 = 595.4 ± 60.9 µmol/L) than rbST cows. The rbST87.5 and rbST125 treatments upregulated the hepatic mRNA expression for somatotropic axis genes (GHR, GHR1A, IGF1, IGFBP3, and SOCS2) on d -7 relative to calving and upregulated the mRNA expression

  15. Molecular and biochemical analysis of the plastidic ADP-glucose transporter (ZmBT1) from Zea mays.

    Science.gov (United States)

    Kirchberger, Simon; Leroch, Michaela; Huynen, Martijn A; Wahl, Markus; Neuhaus, H Ekkehard; Tjaden, Joachim

    2007-08-03

    Physiological studies on the Brittle1 maize mutant have provided circumstantial evidence that ZmBT1 (Zea mays Brittle1 protein) is involved in the ADP-Glc transport into maize endosperm plastids, but up to now, no direct ADP-Glc transport mediated by ZmBT1 has ever been shown. The heterologous synthesis of ZmBT1 in Escherichia coli cells leads to the functional integration of ZmBT1 into the bacterial cytoplasmic membrane. ZmBT1 transports ADP-Glc in counterexchange with ADP with apparent affinities of about 850 and 465 mum, respectively. Recently, a complete ferredoxin/thioredoxin system has been identified in cereal amyloplasts and BT1 has been proposed as a potential Trx target protein (Balmer, Y., Vensel, W. H., Cai, N., Manieri, W., Schurmann, P., Hurkman, W. J., and Buchanan, B. B. (2006) Proc. Natl. Acad. Sci. U. S. A. 103, 2988-2993). Interestingly, we revealed that the transport activity of ZmBT1 is reversibly regulated by redox reagents such as diamide and dithiothreitol. The expression of ZmBT1 is restricted to endosperm tissues during starch synthesis, whereas a recently identified BT1 maize homologue, the ZmBT1-2, exhibits a ubiquitous expression pattern in hetero- and autotrophic tissues indicating different physiological roles for both maize BT1 isoforms. BT1 homologues are present in both mono- and dicotyledonous plants. Phylogenetic analyses classify the BT1 family into two phylogenetically and biochemically distinct groups. The first group comprises BT1 orthologues restricted to cereals where they mediate the ADP-Glc transport into cereal endosperm storage plastids during starch synthesis. The second group occurs in mono- and dicotyledonous plants and is most probably involved in the export of adenine nucleotides synthesized inside plastids.

  16. In vivo assessment of cardiac insulin resistance by nuclear probes using an iodinated tracer of glucose transport

    International Nuclear Information System (INIS)

    Briat, Arnaud; Slimani, Lotfi; Perret, Pascale; Villemain, Daniele; Fagret, Daniel; Ghezzi, Catherine; Halimi, Serge; Demongeot, Jacques

    2007-01-01

    Insulin resistance, implying depressed cellular sensitivity to insulin, is a risk factor for type 2 diabetes and cardiovascular disease. This study is the first step towards the development of a technique of insulin resistance measurement in humans with a new tracer of glucose transport, [ 123 I]6-deoxy-6-iodo-D-glucose (6DIG). We investigated 6DIG kinetics in anaesthetised control rats and in three models of insulin-resistant rats: fructose fed, Zucker and ZDF. The study of myocardial 6DIG activity was performed under two conditions: first, 6DIG was injected under the baseline condition and then it was injected after a bolus injection of insulin. After each injection, radioactivity was measured over 45 min by external detection via NaI probes, in the heart and blood. A tri-compartment model was developed to obtain fractional transfer coefficients of 6DIG from the blood to the heart. These coefficients were significantly increased with insulin in control rats and did not change significantly in insulin-resistant rats. The ratio of the coefficient obtained under insulin to that obtained under basal conditions gave an index of cardiac insulin resistance for each animal. The mean values of these ratios were significantly lower in insulin-resistant than in control rats: 1.16 ± 0.06 vs 2.28 ± 0.18 (p < 0.001) for the fructose-fed group, 0.92 ± 0.05 vs 1.62 ± 0.25 (p < 0.01) for the Zucker group and 1.34 ± 0.06 vs 2.01 ± 0.26 (p < 0.05) for the ZDF group. These results show that 6DIG could be a useful tracer to image cardiac insulin resistance. (orig.)

  17. In vivo assessment of cardiac insulin resistance by nuclear probes using an iodinated tracer of glucose transport

    Energy Technology Data Exchange (ETDEWEB)

    Briat, Arnaud; Slimani, Lotfi; Perret, Pascale; Villemain, Daniele; Fagret, Daniel; Ghezzi, Catherine [INSERM, E0340, Radiopharmaceutiques Biocliniques, Grenoble (France); Univ Grenoble, Grenoble (France); Halimi, Serge [Univ Grenoble, Grenoble (France); Hopital Michallon, Service de Diabetologie, CHRU Grenoble, Grenoble (France); Demongeot, Jacques [Univ Grenoble, Grenoble (France); CNRS, UMR 5525, Grenoble (France)

    2007-11-15

    Insulin resistance, implying depressed cellular sensitivity to insulin, is a risk factor for type 2 diabetes and cardiovascular disease. This study is the first step towards the development of a technique of insulin resistance measurement in humans with a new tracer of glucose transport, [{sup 123}I]6-deoxy-6-iodo-D-glucose (6DIG). We investigated 6DIG kinetics in anaesthetised control rats and in three models of insulin-resistant rats: fructose fed, Zucker and ZDF. The study of myocardial 6DIG activity was performed under two conditions: first, 6DIG was injected under the baseline condition and then it was injected after a bolus injection of insulin. After each injection, radioactivity was measured over 45 min by external detection via NaI probes, in the heart and blood. A tri-compartment model was developed to obtain fractional transfer coefficients of 6DIG from the blood to the heart. These coefficients were significantly increased with insulin in control rats and did not change significantly in insulin-resistant rats. The ratio of the coefficient obtained under insulin to that obtained under basal conditions gave an index of cardiac insulin resistance for each animal. The mean values of these ratios were significantly lower in insulin-resistant than in control rats: 1.16 {+-} 0.06 vs 2.28 {+-} 0.18 (p < 0.001) for the fructose-fed group, 0.92 {+-} 0.05 vs 1.62 {+-} 0.25 (p < 0.01) for the Zucker group and 1.34 {+-} 0.06 vs 2.01 {+-} 0.26 (p < 0.05) for the ZDF group. These results show that 6DIG could be a useful tracer to image cardiac insulin resistance. (orig.)

  18. IRE1 KNOCKDOWN MODIFIES THE GLUTAMINE AND GLUCOSE DEPRIVATION EFFECT ON THE EXPRESSION OF NUCLEAR GENES ENCODING MITOCHONDRIAL PROTEINS IN U87 GLIOMA CELLS

    Directory of Open Access Journals (Sweden)

    O. O.

    2016-04-01

    Full Text Available We have studied the glucose and glutamine deprivation effect on the expression of nuclear genes encoding mitochondrial proteins in U87 glioma cells in relation to inhibition of inositol requiring enzyme-1 (IRE1. It was shown that glutamine deprivation down-regulated the expression of mitochondrial (NADP+-dependent isocitrate dehydrogenase 2 (IDH2, malic enzyme 2 (ME2, mitochondrial aspartate aminotransferase (GOT2, and subunit B of succinate dehydrogenase (SDHB genes in control glioma cells in gene specific manner. At the same time, the expression level of malate dehydrogenase 2 (MDH2 and subunit D of succinate dehydrogenase (SDHD genes in these cells was not changed upon glutamine deprivation. It was also shown that inhibition of ІRE1 signaling enzyme function in U87 glioma cells modified the glutamine deprivation effect on the expression of all studied genes. Furthermore, the expression of the majority of studied genes was resistant to glucose deprivation, except IDH2 and SDHB genes, which expression levels were slightly down-regulated. Inhibition of IRE1 modified the effect of glucose deprivation on ME2, SDHB, SDHD, and GOT2 genes expression. Therefore, glucose and glutamine deprivation affected the expression level of the majority of nuclear genes encoding mitochondrial proteins in relation to the functional activity of IRE1 enzyme, which is a central mediator of endoplasmic reticulum stress and controls cell proliferation and tumor growth.

  19. Effect of prolonged intravenous glucose and essential amino acid infusion on nitrogen balance, muscle protein degradation and ubiquitin-conjugating enzyme gene expression in calves

    Directory of Open Access Journals (Sweden)

    Scaife Jes R

    2008-02-01

    Full Text Available Abstract Background Intravenous infusions of glucose and amino acids increase both nitrogen balance and muscle accretion. We hypothesised that co-infusion of glucose (to stimulate insulin and essential amino acids (EAA would act additively to improve nitrogen balance by decreasing muscle protein degradation in association with alterations in muscle expression of components of the ubiquitin-proteasome proteolytic pathway. Methods We examined the effect of a 5 day intravenous infusions of saline, glucose, EAA and glucose + EAA, on urinary nitrogen excretion and muscle protein degradation. We carried out the study in 6 restrained calves since ruminants offer the advantage that muscle protein degradation can be assessed by excretion of 3 methyl-histidine and multiple muscle biopsies can be taken from the same animal. On the final day of infusion blood samples were taken for hormone and metabolite measurement and muscle biopsies for expression of ubiquitin, the 14-kDa E2 ubiquitin conjugating enzyme, and proteasome sub-units C2 and C8. Results On day 5 of glucose infusion, plasma glucose, insulin and IGF-1 concentrations were increased while urea nitrogen excretion and myofibrillar protein degradation was decreased. Co-infusion of glucose + EAA prevented the loss of urinary nitrogen observed with EAA infusions alone and enhanced the increase in plasma IGF-1 concentration but there was no synergistic effect of glucose + EAA on the decrease in myofibrillar protein degradation. Muscle mRNA expression of the ubiquitin conjugating enzyme, 14-kDa E2 and proteasome sub-unit C2 were significantly decreased, after glucose but not amino acid infusions, and there was no further response to the combined infusions of glucose + EAA. Conclusion Prolonged glucose infusion decreases myofibrillar protein degradation, prevents the excretion of infused EAA, and acts additively with EAA to increase plasma IGF-1 and improve net nitrogen balance. There was no evidence of

  20. Effect of prolonged intravenous glucose and essential amino acid infusion on nitrogen balance, muscle protein degradation and ubiquitin-conjugating enzyme gene expression in calves

    Science.gov (United States)

    Sadiq, Fouzia; Crompton, Leslie A; Scaife, Jes R; Lomax, Michael A

    2008-01-01

    Background Intravenous infusions of glucose and amino acids increase both nitrogen balance and muscle accretion. We hypothesised that co-infusion of glucose (to stimulate insulin) and essential amino acids (EAA) would act additively to improve nitrogen balance by decreasing muscle protein degradation in association with alterations in muscle expression of components of the ubiquitin-proteasome proteolytic pathway. Methods We examined the effect of a 5 day intravenous infusions of saline, glucose, EAA and glucose + EAA, on urinary nitrogen excretion and muscle protein degradation. We carried out the study in 6 restrained calves since ruminants offer the advantage that muscle protein degradation can be assessed by excretion of 3 methyl-histidine and multiple muscle biopsies can be taken from the same animal. On the final day of infusion blood samples were taken for hormone and metabolite measurement and muscle biopsies for expression of ubiquitin, the 14-kDa E2 ubiquitin conjugating enzyme, and proteasome sub-units C2 and C8. Results On day 5 of glucose infusion, plasma glucose, insulin and IGF-1 concentrations were increased while urea nitrogen excretion and myofibrillar protein degradation was decreased. Co-infusion of glucose + EAA prevented the loss of urinary nitrogen observed with EAA infusions alone and enhanced the increase in plasma IGF-1 concentration but there was no synergistic effect of glucose + EAA on the decrease in myofibrillar protein degradation. Muscle mRNA expression of the ubiquitin conjugating enzyme, 14-kDa E2 and proteasome sub-unit C2 were significantly decreased, after glucose but not amino acid infusions, and there was no further response to the combined infusions of glucose + EAA. Conclusion Prolonged glucose infusion decreases myofibrillar protein degradation, prevents the excretion of infused EAA, and acts additively with EAA to increase plasma IGF-1 and improve net nitrogen balance. There was no evidence of synergistic effects between

  1. ¿Cómo se transporta la glucosa a través de la membrana celular? How is glucose transported through cell membrane?

    OpenAIRE

    Diana Patricia Díaz Hernández; Luis Carlos Burgos Herrera

    2002-01-01

    La glucosa es el principal sustrato energético de la célula y para su ingreso requiere una proteína transportadora en la membrana celular. Se han descrito dos sistemas de transporte de glucosa y de otros monosacáridos: los transportadores de sodio y glucosa llamados SGLT ( sodium-glucose transporters) y los transportadores de glucosa llamados GLUT ( glucosa transporters). En este artículo se presenta una revisión de las principales características moleculares, bioquímicas y funcionales de los...

  2. Phenobarbital reduces blood glucose and gluconeogenesis through down-regulation of phosphoenolpyruvate carboxykinase (GTP) gene expression in rats.

    Science.gov (United States)

    Oda, Hiroaki; Okuda, Yuji; Yoshida, Yukiko; Kimura, Noriko; Kakinuma, Atsushi

    2015-10-23

    The regulatory mechanism of phosphoenolpyruvate carboykinase (GTP) (EC 4.1.1.32) (PEPCK) gene expression and gluconeogenesis by phenobarbital (PB), which is known to induce drug-metabolizing enzymes, was investigated. Higher level of PEPCK mRNA was observed in spherical rat primary hepatocytes on EHS-gel than monolayer hepatocytes on TIC (type I collagen). We found that PB directly suppressed PEPCK gene expression in spherical hepatocytes on EHS-gel, but not in those on TIC. PB strongly suppressed cAMP-dependent induction of PEPCK gene expression. Tyrosine aminotransferase (TAT), another gluconeogenic enzyme, was induced by cAMP, but not suppressed by PB. Chronic administration of PB reduced hepatic PEPCK mRNA in streptozotocin-induced diabetic and nondiabetic rats, and PB