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Erdogan MA, Yusuf D, Christy J, Solmaz V, Erdogan A, Taskiran E, Erbas O. Highly selective SGLT2 inhibitor dapagliflozin reduces seizure activity in pentylenetetrazol-induced murine model of epilepsy. BMC Neurol 2018; 18:81. [PMID: 29879920 PMCID: PMC5991447 DOI: 10.1186/s12883-018-1086-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 05/30/2018] [Indexed: 01/03/2023] Open
Abstract
Background Worldwide, over 10 million individuals suffer from drug-resistant epilepsy. New therapeutic strategies are needed to address this debilitating disease. Inhibition of sodium-glucose linked transporters (SGLTs), which are variably expressed in the brain, has been demonstrated to reduce seizure activity in murine models of epilepsy. Here we investigated the effects of dapagliflozin, a highly competitive SGLT2 inhibitor currently used as a drug for diabetes mellitus, on seizure activity in rats with pentylenetetrazol (PTZ) induced seizures. Methods Laboratory rats (n = 48) were evenly randomized into two experiments, each with four study arms: (1) a vehicle-treated (placebo) arm infused with saline; (2) a control arm infused with PTZ; (3) a treatment arm with PTZ and dapagliflozin at 75 mg/kg, and (4) another treatment arm with PTZ and dapagliflozin at 150 mg/kg. Study subjects were assessed for seizures either via EEG as measured by spike wave percentage (SWP), or clinically via Racine’s scales scores (RSS) and time to first myoclonic jerk (TFMJ). Results Rats treated with dapagliflozin had lower mean SWP on EEG (20.4% versus 75.3% for untreated rats). Behaviorally, treatment with dapagliflozin improved means RSS (2.33 versus 5.5) and mean TFMJ (68.3 versus 196.7 s). All of these findings were statistically significant with p-values of < 0.0001. There was a trend towards even better seizure control with the higher dose of dapagliflozin at 150 mg/kg, however this was not consistently statistically significant. Conclusions Dapagliflozin decreased seizure activity in rats with PTZ–induced seizures. This may be explained by the anti-seizure effects of decreased glucose availability and a reduction in sodium transport across neuronal membranes which can confer a stabilizing effect against excitability and unwanted depolarization. The potential clinical role of dapagliflozin and other SGLT2 inhibitors as anti-seizure medications should be further explored.
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Affiliation(s)
- Mumin Alper Erdogan
- Department of Physiology, Faculty of Medicine, Izmir Katip Celebi University, Izmir, Turkey
| | - Dimas Yusuf
- Faculty of Medicine, University of Alberta, Edmonton, AB, Canada
| | | | - Volkan Solmaz
- Department of Neurology, Faculty of Medicine, Trakya University, Edirne, Turkey
| | - Arife Erdogan
- Department of Emergency Medicine, Izmir Bozyaka Training and Research Hospital, Izmir, Turkey
| | - Emin Taskiran
- Department of Internal Medicine, Tepecik Training and Research Hospital, Izmir, Turkey
| | - Oytun Erbas
- Department of Physiology, Faculty of Medicine, Bilim University, Istanbul, Turkey
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Abstract
Increased understanding of fructose metabolism, which begins with uptake via the intestine, is important because fructose now constitutes a physiologically significant portion of human diets and is associated with increased incidence of certain cancers and metabolic diseases. New insights in our knowledge of intestinal fructose absorption mediated by the facilitative glucose transporter GLUT5 in the apical membrane and by GLUT2 in the basolateral membrane are reviewed. We begin with studies related to structure as well as ligand binding, then revisit the controversial proposition that apical GLUT2 is the main mediator of intestinal fructose absorption. The review then describes how dietary fructose may be sensed by intestinal cells to affect the expression and activity of transporters and fructolytic enzymes, to interact with the transport of certain minerals and electrolytes, and to regulate portal and peripheral fructosemia and glycemia. Finally, it discusses the potential contributions of dietary fructose to gastrointestinal diseases and to the gut microbiome.
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Affiliation(s)
- Ronaldo P Ferraris
- Department of Pharmacology, Physiology and Neuroscience, New Jersey Medical School, Rutgers University, Newark, New Jersey 07946, USA;
| | - Jun-Yong Choe
- Department of Biochemistry and Molecular Biology, Rosalind Franklin University of Medicine and Science, The Chicago Medical School, North Chicago, Illinois 60064, USA;
| | - Chirag R Patel
- Independent Drug Safety Consulting, Wilmington, Delaware 19803, USA;
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53
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Begoyan VV, Weseliński ŁJ, Xia S, Fedie J, Kannan S, Ferrier A, Rao S, Tanasova M. Multicolor GLUT5-permeable fluorescent probes for fructose transport analysis. Chem Commun (Camb) 2018; 54:3855-3858. [PMID: 29594264 DOI: 10.1039/c7cc09809j] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The specificity of carbohydrate transporters towards their substrates poses a significant challenge for the development of molecular probes to monitor sugar uptake in cells for biochemical and biomedical applications. Herein we report a new set of coumarin-based fluorescent sugar conjugates applicable for the analysis of fructose uptake due to their free passage through the fructose-specific transporter GLUT5. The reported probes cover a broad range of the fluorescence spectrum providing essential tools for the evaluation of fructose transport capacity in live cells.
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Affiliation(s)
- V V Begoyan
- Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, Michigan 49331, USA.
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54
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Kannan S, Begoyan VV, Fedie JR, Xia S, Weseliński ŁJ, Tanasova M, Rao S. Metabolism-Driven High-Throughput Cancer Identification with GLUT5-Specific Molecular Probes. BIOSENSORS-BASEL 2018; 8:bios8020039. [PMID: 29642606 PMCID: PMC6022918 DOI: 10.3390/bios8020039] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/19/2018] [Accepted: 04/04/2018] [Indexed: 12/17/2022]
Abstract
Point-of-care applications rely on biomedical sensors to enable rapid detection with high sensitivity and selectivity. Despite advances in sensor development, there are challenges in cancer diagnostics. Detection of biomarkers, cell receptors, circulating tumor cells, gene identification, and fluorescent tagging are time-consuming due to the sample preparation and response time involved. Here, we present a novel approach to target the enhanced metabolism in breast cancers for rapid detection using fluorescent imaging. Fluorescent analogs of fructose target the fructose-specific transporter GLUT5 in breast cancers and have limited to no response from normal cells. These analogs demonstrate a marked difference in adenocarcinoma and premalignant cells leading to a novel detection approach. The vastly different uptake kinetics of the analogs yields two unique signatures for each cell type. We used normal breast cells MCF10A, adenocarcinoma cells MCF7, and premalignant cells MCF10AneoT, with hepatocellular carcinoma cells HepG2 as the negative control. Our data indicated that MCF10AneoT and MCF7 cells had an observable difference in response to only one of the analogs. The response, observed as fluorescence intensity, leads to a two-point assessment of the cells in any sample. Since the treatment time is 10 min, there is potential for use in rapid on-site high-throughput diagnostics.
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Affiliation(s)
- Srinivas Kannan
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, USA;
| | - Vagarshak V. Begoyan
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA; (V.V.B.); (J.R.F.); (S.X.); (Ł.J.W.)
| | - Joseph R. Fedie
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA; (V.V.B.); (J.R.F.); (S.X.); (Ł.J.W.)
| | - Shuai Xia
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA; (V.V.B.); (J.R.F.); (S.X.); (Ł.J.W.)
| | - Łukasz J. Weseliński
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA; (V.V.B.); (J.R.F.); (S.X.); (Ł.J.W.)
| | - Marina Tanasova
- Department of Chemistry, Michigan Technological University, Houghton, MI 49931, USA; (V.V.B.); (J.R.F.); (S.X.); (Ł.J.W.)
- Correspondence: (M.T.); (S.R.); Tel.: +1-906-487-1163 (M.T.); +1-906-487-3230 (S.R.)
| | - Smitha Rao
- Department of Biomedical Engineering, Michigan Technological University, Houghton, MI 49931, USA;
- Correspondence: (M.T.); (S.R.); Tel.: +1-906-487-1163 (M.T.); +1-906-487-3230 (S.R.)
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Placental Expression of Glucose Transporter Proteins in Pregnancies Complicated by Gestational and Pregestational Diabetes Mellitus. Can J Diabetes 2018; 42:209-217. [DOI: 10.1016/j.jcjd.2017.04.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 04/18/2017] [Accepted: 04/24/2017] [Indexed: 12/31/2022]
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56
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Hannou SA, Haslam DE, McKeown NM, Herman MA. Fructose metabolism and metabolic disease. J Clin Invest 2018; 128:545-555. [PMID: 29388924 DOI: 10.1172/jci96702] [Citation(s) in RCA: 307] [Impact Index Per Article: 51.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Increased sugar consumption is increasingly considered to be a contributor to the worldwide epidemics of obesity and diabetes and their associated cardiometabolic risks. As a result of its unique metabolic properties, the fructose component of sugar may be particularly harmful. Diets high in fructose can rapidly produce all of the key features of the metabolic syndrome. Here we review the biology of fructose metabolism as well as potential mechanisms by which excessive fructose consumption may contribute to cardiometabolic disease.
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Affiliation(s)
- Sarah A Hannou
- Division of Endocrinology and Metabolism and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, USA
| | - Danielle E Haslam
- Nutritional Epidemiology Program, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA
| | - Nicola M McKeown
- Nutritional Epidemiology Program, Jean Mayer US Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts, USA
| | - Mark A Herman
- Division of Endocrinology and Metabolism and Duke Molecular Physiology Institute, Duke University Medical Center, Durham, North Carolina, USA
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Abstract
Glucose is metabolized through anaerobic glycolysis and aerobic oxidative phosphorylation (OXPHOS). Perturbing glucose uptake and its subsequent metabolism can alter both glycolytic and OXPHOS pathways and consequently lactate and/or oxygen consumption. Production and secretion of lactate, as a consequence of glycolysis, leads to acidification of the extracellular medium. Molecular oxygen is the final electron acceptor in the electron transport chain, facilitating oxidative phosphorylation of ADP to ATP. The alterations in extracellular acidification and/or oxygen consumption can thus be used as indirect readouts of glucose metabolism and assessing the impact of inhibiting glucose transport through specific glucose transporters (GLUTs). The Seahorse bioenergetics analyzer can measure both the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR). The proposed methodology affords a robust, high-throughput method to screen for GLUT inhibition in cells engineered to express specific GLUTs, providing live cell read-outs upon GLUT inhibition.
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58
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Wuest M, Hamann I, Bouvet V, Glubrecht D, Marshall A, Trayner B, Soueidan OM, Krys D, Wagner M, Cheeseman C, West F, Wuest F. Molecular Imaging of GLUT1 and GLUT5 in Breast Cancer: A Multitracer Positron Emission Tomography Imaging Study in Mice. Mol Pharmacol 2017; 93:79-89. [DOI: 10.1124/mol.117.110007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2017] [Accepted: 11/13/2017] [Indexed: 01/08/2023] Open
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Shimada M, Hibino M, Takeshita A. Dietary supplementation with myo -inositol reduces hepatic triglyceride accumulation and expression of both fructolytic and lipogenic genes in rats fed a high-fructose diet. Nutr Res 2017; 47:21-27. [DOI: 10.1016/j.nutres.2017.08.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 08/18/2017] [Accepted: 08/22/2017] [Indexed: 10/19/2022]
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Szablewski L. Distribution of glucose transporters in renal diseases. J Biomed Sci 2017; 24:64. [PMID: 28854935 PMCID: PMC5577680 DOI: 10.1186/s12929-017-0371-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 08/23/2017] [Indexed: 02/06/2023] Open
Abstract
Kidneys play an important role in glucose homeostasis. Renal gluconeogenesis prevents hypoglycemia by releasing glucose into the blood stream. Glucose homeostasis is also due, in part, to reabsorption and excretion of hexose in the kidney.Lipid bilayer of plasma membrane is impermeable for glucose, which is hydrophilic and soluble in water. Therefore, transport of glucose across the plasma membrane depends on carrier proteins expressed in the plasma membrane. In humans, there are three families of glucose transporters: GLUT proteins, sodium-dependent glucose transporters (SGLTs) and SWEET. In kidney, only GLUTs and SGLTs protein are expressed. Mutations within genes that code these proteins lead to different renal disorders and diseases. However, diseases, not only renal, such as diabetes, may damage expression and function of renal glucose transporters.
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Affiliation(s)
- Leszek Szablewski
- Medical University of Warsaw, Chair & Department of General Biology & Parasitology, Center for Biostructure Research, 5 Chalubinskiego Str., 02-004, Warsaw, Poland.
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61
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Abstract
Facilitative carbohydrate transporters-Gluts-have received wide attention over decades due to their essential role in nutrient uptake and links with various metabolic disorders, including diabetes, obesity, and cancer. Endeavors directed towards understanding the mechanisms of Glut-mediated nutrient uptake have resulted in a multidisciplinary research field spanning protein chemistry, chemical biology, organic synthesis, crystallography, and biomolecular modeling. Gluts became attractive targets for cancer research and medicinal chemistry, leading to the development of new approaches to cancer diagnostics and providing avenues for cancer-targeting therapeutics. In this review, the current state of knowledge of the molecular interactions behind Glut-mediated sugar uptake, Glut-targeting probes, therapeutics, and inhibitors are discussed.
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Affiliation(s)
- Marina Tanasova
- Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI, 49931, USA
| | - Joseph R Fedie
- Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI, 49931, USA
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62
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A Glimpse of Membrane Transport through Structures—Advances in the Structural Biology of the GLUT Glucose Transporters. J Mol Biol 2017; 429:2710-2725. [DOI: 10.1016/j.jmb.2017.07.009] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Revised: 07/13/2017] [Accepted: 07/15/2017] [Indexed: 01/17/2023]
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63
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Iglesias-Fernandez J, Quinn PJ, Naftalin RJ, Domene C. Membrane Phase-Dependent Occlusion of Intramolecular GLUT1 Cavities Demonstrated by Simulations. Biophys J 2017; 112:1176-1184. [PMID: 28355545 DOI: 10.1016/j.bpj.2017.01.030] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 12/27/2022] Open
Abstract
Experimental evidence has shown a close correlation between the composition and physical state of the membrane bilayer and glucose transport activity via the glucose transporter GLUT1. Cooling alters the membrane lipids from the fluid to gel phase, and also causes a large decrease in the net glucose transport rate. The goal of this study is to investigate how the physical phase of the membrane alters glucose transporter structural dynamics using molecular-dynamics simulations. Simulations from an initial fluid to gel phase reduce the size of the cavities and tunnels traversing the protein and connecting the external regions of the transporter and the central binding site. These effects can be ascribed solely to membrane structural changes since in silico cooling of the membrane alone, while maintaining the higher protein temperature, shows protein structural and dynamic changes very similar to those observed with uniform cooling. These results demonstrate that the protein structure is sensitive to the membrane phase, and have implications for how transmembrane protein structures respond to their physical environment.
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Affiliation(s)
| | - Peter J Quinn
- Department of Biochemistry, School of Medicine, King's College London, London, United Kingdom
| | - Richard J Naftalin
- Department of Physiology, School of Medicine, King's College London, London, United Kingdom; BHF Centre of Research Excellence, School of Medicine, King's College London, London, United Kingdom
| | - Carmen Domene
- Department of Chemistry, School of Medicine, King's College London, London, United Kingdom; Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom.
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64
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Fan J, Mei J, Zhang MZ, Yuan F, Li SZ, Yu GR, Chen LH, Tang Q, Xian CJ. Clinicopathological significance of glucose transporter protein-1 overexpression in human osteosarcoma. Oncol Lett 2017; 14:2439-2445. [PMID: 28781680 DOI: 10.3892/ol.2017.6437] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2015] [Accepted: 04/13/2017] [Indexed: 01/09/2023] Open
Abstract
Although previous studies have demonstrated that Glut-1 is the predominant glucose transporter, is significantly overexpressed in various types of tumor and is correlated with poor prognosis, the potential function and clinical value of Glut-1 expression in osteosarcoma remains largely unclear. In particular, the prospective associations between Glut-1 expression levels and clinicopathological factors remains to be elucidated. In the present study, immunohistochemistry was performed to detect Glut-1 protein expression in 51 paired osteosarcoma specimens and adjacent non-cancerous tissues, and reverse transcription-quantitative polymerase chain reaction analysis was performed to examine Glut-1 mRNA expression levels in 6 pairs of these tissues. Statistical analyses were conducted to determine the associations between Glut-1 expression and various clinicopathological parameters. Glut-1 protein was revealed to be overexpressed in 38 (74.5%) osteosarcoma tissues, but only in 6 (11.8%) adjacent non-cancerous tissues. Glut-1 mRNA levels were also upregulated in osteosarcoma tissues compared with adjacent non-cancerous tissues. While there were no clear statistical relationships between Glut-1 expression and patient sex, resection, tumor location, size, T stage and adjuvant treatment, Glut-1 expression levels were significantly associated with age, tumor-node-metastasis stage, lymph node metastasis and survival. The median survival time in patients with low Glut-1 expression levels was longer than in patients with a high expression level. Glut-1 was significantly overexpressed in osteosarcoma tissues, and Glut-1 expression was associated with clinicopathological factors which upregulate the invasion and metastasis of osteosarcoma, and may be a potential predictor of survival in patients with osteosarcoma.
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Affiliation(s)
- Jian Fan
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai 200065, P.R. China
| | - Jiong Mei
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai 200065, P.R. China
| | - Ming-Zhu Zhang
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai 200065, P.R. China
| | - Feng Yuan
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai 200065, P.R. China
| | - Shan-Zhu Li
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai 200065, P.R. China
| | - Guang-Rong Yu
- Department of Orthopedics, Tongji Hospital, Tongji University, Shanghai 200065, P.R. China
| | - Long-Hui Chen
- Pi-wei Institute, Guangzhou University of Chinese Medicine, Guangzhou 510405, P.R. China
| | - Qian Tang
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia 5001, Australia
| | - Cory J Xian
- Sansom Institute for Health Research, School of Pharmacy and Medical Sciences, University of South Australia, Adelaide, South Australia 5001, Australia
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65
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Wakisaka M, Nagao T. Sodium glucose cotransporter 2 in mesangial cells and retinal pericytes and its implications for diabetic nephropathy and retinopathy. Glycobiology 2017; 27:691-695. [PMID: 28535208 PMCID: PMC5881757 DOI: 10.1093/glycob/cwx047] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2017] [Revised: 05/12/2017] [Accepted: 05/19/2017] [Indexed: 12/29/2022] Open
Abstract
Retinopathy and nephropathy are life-threatening diabetic complications that decrease patient quality of life. Although the mechanisms underlying these conditions have been extensively studied, they remain unknown. Recent reports have demonstrated the presence of sodium glucose cotransporter 2 (SGLT2) in retinal pericytes and mesangial cells. Hyperglycemia results in functional and morphological changes in these cells, but these effects are attenuated by phlorizin, a nonselective SGLT inhibitor. Based on these findings, we hypothesized that SGLT2 plays a pivotal role in the development of diabetic nephropathy and retinopathy and that SGLT2 inhibitors may directly protect against these complications.
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Affiliation(s)
- Masarori Wakisaka
- Wakisaka Naika (Wakisaka Internal Medicine Clinic), Fujisaki 1-24-19, Fukuoka, 814-0013, Japan
| | - Tetsuhiko Nagao
- Midori no Clinic (Midori Internal Medicine Clinic), Aoba 7-26-1, Fukuoka 813-0025, Japan
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66
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Kumar Kondapi VP, Soueidan OM, Cheeseman CI, West FG. Tunable GLUT-Hexose Binding and Transport via Modulation of Hexose C-3 Hydrogen-Bonding Capabilities. Chemistry 2017; 23:8073-8081. [DOI: 10.1002/chem.201701329] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Indexed: 01/21/2023]
Affiliation(s)
- Venkata Pavan Kumar Kondapi
- Department of Chemistry; University of Alberta; 11227 Saskatchewan Dr. Edmonton AB, CA T6G 2G2 Canada
- Department of Physiology; University of Alberta; Medical Sciences Building Edmonton AB, CA T6G 2H7 Canada
| | - Olivier-Mohamad Soueidan
- Department of Chemistry; University of Alberta; 11227 Saskatchewan Dr. Edmonton AB, CA T6G 2G2 Canada
- Department of Physiology; University of Alberta; Medical Sciences Building Edmonton AB, CA T6G 2H7 Canada
| | - Christopher I. Cheeseman
- Department of Physiology; University of Alberta; Medical Sciences Building Edmonton AB, CA T6G 2H7 Canada
| | - Frederick G. West
- Department of Chemistry; University of Alberta; 11227 Saskatchewan Dr. Edmonton AB, CA T6G 2G2 Canada
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Soueidan OM, Scully TW, Kaur J, Panigrahi R, Belovodskiy A, Do V, Matier CD, Lemieux MJ, Wuest F, Cheeseman C, West FG. Fluorescent Hexose Conjugates Establish Stringent Stereochemical Requirement by GLUT5 for Recognition and Transport of Monosaccharides. ACS Chem Biol 2017; 12:1087-1094. [PMID: 28205432 DOI: 10.1021/acschembio.6b01101] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The specificity characteristics of transporters can be exploited for the development of novel diagnostic therapeutic probes. The facilitated hexose transporter family (GLUTs) has a distinct set of preferences for monosaccharide substrates, and while some are expressed ubiquitously (e.g., GLUT1), others are quite tissue specific (e.g., GLUT5, which is overexpressed in some breast cancer tissues). While these differences have enabled the development of new molecular probes based upon hexose- and tissue-selective uptake, substrate design for compounds targeting these GLUT transporters has been encumbered by a limited understanding of the molecular interactions at play in hexose binding and transport. Four new fluorescently labeled hexose derivatives have been prepared, and their transport characteristics were examined in two breast cancer cell lines expressing mainly GLUTs 1, 2, and 5. Our results demonstrate, for the first time, a stringent stereochemical requirement for recognition and transport by GLUT5. 6-NBDF, in which all substituents are in the d-fructose configuration, is taken up rapidly into both cell lines via GLUT5. On the other hand, inversion of a single stereocenter at C-3 (6-NBDP), C-4 (6-NBDT), or C-5 (6-NDBS) results in selective transport via GLUT1. An in silico docking study employing the recently published GLUT5 crystal structure confirms this stereochemical dependence. This work provides insight into hexose-GLUT interactions at the molecular level and will facilitate structure-based design of novel substrates targeting individual members of the GLUT family and forms the basis of new cancer imaging or therapeutic agents.
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Affiliation(s)
- Olivier-Mohamad Soueidan
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2
- Department
of Physiology, University of Alberta, 7-55 Medical Sciences Building, Edmonton, Alberta, Canada T6G 2H7
| | - Thomas W. Scully
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2
| | - Jatinder Kaur
- Department
of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada T6G 1Z2
| | - Rashmi Panigrahi
- Department
of Biochemistry, University of Alberta, 451 Medical Sciences Building, Edmonton, Alberta, Canada T6G 2H7
| | - Alexandr Belovodskiy
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2
| | - Victor Do
- Department
of Physiology, University of Alberta, 7-55 Medical Sciences Building, Edmonton, Alberta, Canada T6G 2H7
| | - Carson D. Matier
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2
| | - M. Joanne Lemieux
- Department
of Biochemistry, University of Alberta, 451 Medical Sciences Building, Edmonton, Alberta, Canada T6G 2H7
| | - Frank Wuest
- Department
of Oncology, University of Alberta, Cross Cancer Institute, Edmonton, Alberta, Canada T6G 1Z2
| | - Chris Cheeseman
- Department
of Physiology, University of Alberta, 7-55 Medical Sciences Building, Edmonton, Alberta, Canada T6G 2H7
| | - F. G. West
- Department
of Chemistry, University of Alberta, 11227 Saskatchewan Drive, Edmonton, Alberta, Canada T6G 2G2
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Park TJ, Reznick J, Peterson BL, Blass G, Omerbašić D, Bennett NC, Kuich PHJL, Zasada C, Browe BM, Hamann W, Applegate DT, Radke MH, Kosten T, Lutermann H, Gavaghan V, Eigenbrod O, Bégay V, Amoroso VG, Govind V, Minshall RD, Smith ESJ, Larson J, Gotthardt M, Kempa S, Lewin GR. Fructose-driven glycolysis supports anoxia resistance in the naked mole-rat. Science 2017; 356:307-311. [DOI: 10.1126/science.aab3896] [Citation(s) in RCA: 404] [Impact Index Per Article: 57.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 03/01/2017] [Indexed: 12/31/2022]
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69
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Tups A, Benzler J, Sergi D, Ladyman SR, Williams LM. Central Regulation of Glucose Homeostasis. Compr Physiol 2017; 7:741-764. [DOI: 10.1002/cphy.c160015] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Stanirowski PJ, Szukiewicz D, Pyzlak M, Abdalla N, Sawicki W, Cendrowski K. 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. Endocrine 2017; 55:799-808. [PMID: 27981520 PMCID: PMC5316392 DOI: 10.1007/s12020-016-1202-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 12/08/2016] [Indexed: 12/21/2022]
Abstract
PURPOSE 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. METHODS 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. RESULTS 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 < .05). Significantly increased GLUT-1 expression was observed only in placental specimens from patients with PGDM (p < .05). No statistically significant differences in GLUT expression were found between GDMG1 patients and healthy controls. CONCLUSIONS The results of the study confirmed the presence of GLUT-1, GLUT-4 and GLUT-9 proteins in the trophoblast from both, uncomplicated and 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.
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Affiliation(s)
- Paweł Jan Stanirowski
- Department of Obstetrics, Gynecology and Oncology, II Faculty of Medicine, Medical University of Warsaw, Mazovian Bródno Hospital, Kondratowicza 8, 03-242, Warsaw, Poland.
| | - Dariusz Szukiewicz
- Department of General and Experimental Pathology with Centre for Preclinical Research and Technology (CEPT), II Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Michał Pyzlak
- Department of General and Experimental Pathology with Centre for Preclinical Research and Technology (CEPT), II Faculty of Medicine, Medical University of Warsaw, Warsaw, Poland
| | - Nabil Abdalla
- Department of Obstetrics, Gynecology and Oncology, II Faculty of Medicine, Medical University of Warsaw, Mazovian Bródno Hospital, Kondratowicza 8, 03-242, Warsaw, Poland
| | - Włodzimierz Sawicki
- Department of Obstetrics, Gynecology and Oncology, II Faculty of Medicine, Medical University of Warsaw, Mazovian Bródno Hospital, Kondratowicza 8, 03-242, Warsaw, Poland
| | - Krzysztof Cendrowski
- Department of Obstetrics, Gynecology and Oncology, II Faculty of Medicine, Medical University of Warsaw, Mazovian Bródno Hospital, Kondratowicza 8, 03-242, Warsaw, Poland
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Functional characterization of a novel disaccharide transporter in lobster hepatopancreas. J Comp Physiol B 2017; 187:563-573. [PMID: 28180997 DOI: 10.1007/s00360-017-1058-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Revised: 12/26/2016] [Accepted: 01/11/2017] [Indexed: 01/01/2023]
Abstract
In animals, the accepted model of carbohydrate digestion and absorption involves reduction of disaccharides into the monosaccharides glucose, fructose, and galactose followed by their individual transmembrane transport into cells. In 2011, a gene for a distinct disaccharide sucrose transporter (SCRT) was found in Drosophila melanogaster and characterized in a yeast expression system. The purpose of the present investigation was to functionally identify and characterize a putative disaccharide transporter analog in the hepatopancreas of the American lobster, Homarus americanus. Purified hepatopancreatic brush-border membrane vesicles (BBMV) were used in transport experiments using 14C-sucrose and a Millipore filter isolation technique. In the absence of sodium, an external pH of 4 significantly stimulated the uptake of 14C-sucrose compared to that occurring at pH 5, 6, or 7. At pH 7, increasing external concentrations of sodium increased 14C-sucrose uptake by BBMV in a hyperbolic fashion and this stimulation was significantly reduced when the pH was changed to 4, suggesting that both protons and sodium ions were each capable of driving the uptake of the sugar. In experiments with a variety of monosaccharides, disaccharides, and trisaccharides, used as potential inhibitors of 14C-sucrose uptake, only maltose and trehalose inhibited carrier-mediated 14C-sucrose transport. An additional experiment showed that 20 mM maltose was a competitive inhibitor of 14C-sucrose uptake. The use of a putative lobster SCRT by both maltose and trehalose is nutritionally appropriate for lobsters as they commonly digest glycogen and chitin, polymers of maltose and trehalose, respectively. These findings suggest there is a brush-border proton- or sodium-dependent, hepatopancreatic carrier process, shared by sucrose, maltose, and trehalose, that may function to absorb disaccharides that are produced from digestion of naturally occurring dietary constituents.
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Au DT, Strickland DK, Muratoglu SC. The LDL Receptor-Related Protein 1: At the Crossroads of Lipoprotein Metabolism and Insulin Signaling. J Diabetes Res 2017; 2017:8356537. [PMID: 28584820 PMCID: PMC5444004 DOI: 10.1155/2017/8356537] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/11/2017] [Indexed: 12/30/2022] Open
Abstract
The metabolic syndrome is an escalating worldwide public health concern. Defined by a combination of physiological, metabolic, and biochemical factors, the metabolic syndrome is used as a clinical guideline to identify individuals with a higher risk for type 2 diabetes and cardiovascular disease. Although risk factors for type 2 diabetes and cardiovascular disease have been known for decades, the molecular mechanisms involved in the pathophysiology of these diseases and their interrelationship remain unclear. The LDL receptor-related protein 1 (LRP1) is a large endocytic and signaling receptor that is widely expressed in several tissues. As a member of the LDL receptor family, LRP1 is involved in the clearance of chylomicron remnants from the circulation and has been demonstrated to be atheroprotective. Recently, studies have shown that LRP1 is involved in insulin receptor trafficking and regulation and glucose metabolism. This review summarizes the role of tissue-specific LRP1 in insulin signaling and its potential role as a link between lipoprotein and glucose metabolism in diabetes.
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Affiliation(s)
- Dianaly T. Au
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Dudley K. Strickland
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Selen C. Muratoglu
- Center for Vascular and Inflammatory Diseases, University of Maryland School of Medicine, Baltimore, MD, USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
- *Selen C. Muratoglu:
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Szablewski L. Glucose Transporters in Brain: In Health and in Alzheimer’s Disease. J Alzheimers Dis 2016; 55:1307-1320. [DOI: 10.3233/jad-160841] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Wellberg EA, Johnson S, Finlay-Schultz J, Lewis AS, Terrell KL, Sartorius CA, Abel ED, Muller WJ, Anderson SM. The glucose transporter GLUT1 is required for ErbB2-induced mammary tumorigenesis. Breast Cancer Res 2016; 18:131. [PMID: 27998284 PMCID: PMC5168867 DOI: 10.1186/s13058-016-0795-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 11/25/2016] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Altered tumor cell metabolism is an emerging hallmark of cancer; however, the precise role for glucose in tumor initiation is not known. GLUT1 (SLC2A1) is expressed in breast cancer cells and is likely responsible for avid glucose uptake observed in established tumors. We have shown that GLUT1 was necessary for xenograft tumor formation from primary mammary cells transformed with the polyomavirus middle-T antigen but that it was not necessary for growth after tumors had formed in vivo, suggesting a differential requirement for glucose depending on the stage of tumorigenesis. METHODS To determine whether GLUT1 is required early during mammary tumorigenesis, we crossed MMTV-NIC mice, which express activated HER2/NEU/ERBB2 and Cre recombinase, to Slc2a1 Flox/Flox (GLUT1Flox/Flox) mice to generate NIC-GLUT1+/+, NIC-GLUT1Flox/+, and NIC-GLUT1Flox/Flox mice. In addition, we evaluated effects of glucose restriction or GLUT1 inhibition on transformation in MCF10A-ERBB2 breast epithelial cells in three-dimensional culture. Finally, we utilized global gene expression profiling data of primary human breast tumors to determine the relationship between SLC2A1 and stage of tumorigenesis. RESULTS All of the NIC-GLUT1+/+ mice developed tumors in less than 200 days. In contrast, only 1 NIC-GLUT1Flox/Flox mouse and 1 NIC-GLUT1Flox/+ mouse developed mammary tumors, even after 18 months. Mammary gland development was not disrupted in NIC mice lacking GLUT1; however, epithelial content of mature glands was reduced compared to NIC-GLUT1Flox/+ mice. In MCF10A-ERBB2 cells, glucose restriction or GLUT1 inhibition blocked transformation induced by activated ERBB2 through reduced cell proliferation. In human breast cancers, SLC2A1 was higher in ductal carcinoma in situ compared to the normal breast, but lower in invasive versus in situ lesions, suggesting the requirement for GLUT1 decreases as tumors progress. CONCLUSIONS This study demonstrates a strict requirement for GLUT1 in the early stages of mammary tumorigenesis in vitro and in vivo. While metabolic adaptation has emerged as a hallmark of cancer, our data indicate that early tumor cells rely heavily on glucose and highlight the potential for glucose restriction as a breast cancer preventive strategy.
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Affiliation(s)
- Elizabeth A Wellberg
- Department of Pathology, MS 8401, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Box 8104, Aurora, CO, 80045, USA.
| | - Stevi Johnson
- Department of Pathology, MS 8401, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Box 8104, Aurora, CO, 80045, USA
| | - Jessica Finlay-Schultz
- Department of Pathology, MS 8401, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Box 8104, Aurora, CO, 80045, USA
| | - Andrew S Lewis
- Department of Pathology, MS 8401, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Box 8104, Aurora, CO, 80045, USA
| | - Kristina L Terrell
- Department of Pathology, MS 8401, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Box 8104, Aurora, CO, 80045, USA
| | - Carol A Sartorius
- Department of Pathology, MS 8401, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Box 8104, Aurora, CO, 80045, USA.,Program in Cancer Biology, MS 8401, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - E Dale Abel
- Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - William J Muller
- Department of Biochemistry, McGill University, Montreal, Quebec, H3A 1A3, Canada.,Rosalind and Morris Goodman Cancer Center, McGill University, Montreal, Quebec, H3A 1A3, Canada
| | - Steven M Anderson
- Department of Pathology, MS 8401, University of Colorado Anschutz Medical Campus, 12801 East 17th Avenue, Box 8104, Aurora, CO, 80045, USA. .,Program in Cancer Biology, MS 8401, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA. .,Program in Molecular Biology, MS 8401, University of Colorado Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Kalsbeek MJT, Mulder L, Yi CX. Microglia energy metabolism in metabolic disorder. Mol Cell Endocrinol 2016; 438:27-35. [PMID: 27687525 DOI: 10.1016/j.mce.2016.09.028] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2016] [Revised: 09/23/2016] [Accepted: 09/26/2016] [Indexed: 12/22/2022]
Abstract
Microglia are the resident macrophages of the CNS, and are in charge of maintaining a healthy microenvironment to ensure neuronal survival. Microglia carry out a non-stop patrol of the CNS, make contact with neurons and look for abnormalities, all of which requires a vast amount of energy. This non-signaling energy demand increases after activation by pathogens, neuronal damage or other kinds of stimulation. Of the three major energy substrates - glucose, fatty acids and glutamine - glucose is crucial for microglia survival and several glucose transporters are expressed to supply sufficient glucose influx. Fatty acids are another source of energy for microglia and have also been shown to strongly influence microglial immune activity. Glutamine, although possibly suitable for use as an energy substrate by microglia, has been shown to have neurotoxic effects when overloaded. Microglial fuel metabolism might be associated with microglial reactivity under different pathophysiological conditions and a microglial fuel switch may thus be the underlying cause of hypothalamic dysregulation, which is associated with obesity.
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Affiliation(s)
- Martin J T Kalsbeek
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam (UvA), Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
| | - Laurie Mulder
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam (UvA), Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Chun-Xia Yi
- Department of Endocrinology and Metabolism, Academic Medical Center (AMC), University of Amsterdam (UvA), Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
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Defries DM, Taylor CG, Zahradka P. GLUT3 is present in Clone 9 liver cells and translocates to the plasma membrane in response to insulin. Biochem Biophys Res Commun 2016; 477:433-9. [PMID: 27320866 DOI: 10.1016/j.bbrc.2016.06.081] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 06/15/2016] [Indexed: 11/29/2022]
Abstract
Clone 9 cells have been reported to express only the GLUT1 facilitative glucose transporter; however, previous studies have not examined Clone 9 cells for GLUT3 content. The current study sought to profile the presence of glucose transporters in Clone 9 cells, H4IIE hepatoma cells, and L6 myoblasts and myotubes. While the other cell types contained the expected complement of transporters, Clone 9 cells had GLUT3 which was previously not reported. Interestingly, both GLUT3 mRNA and protein were detected in Clone 9 cells, but only mRNA for GLUT1 was detected. Glucose transport in Clone 9 cells was insulin-sensitive in a concentration-dependent manner, concomitant with the presence of GLUT3 in the plasma membrane after insulin treatment. Although basal glucose uptake was unaffected, insulin-stimulated glucose uptake was abolished with siRNA-mediated GLUT3 knockdown. These results contradict previous reports that Clone 9 cells exclusively express GLUT1 and suggest GLUT3 is a key insulin-sensitive glucose transporter required for insulin-stimulated glucose uptake by Clone 9 cells.
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Affiliation(s)
- Danielle M Defries
- Department of Human Nutritional Sciences, University of Manitoba, 209 Human Ecology Building, Winnipeg, Manitoba R3T 292, Canada; Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada; Department of Kinesiology and Applied Health, University of Winnipeg, 515 Portage Avenue, Winnipeg, Manitoba R3B 2E9, Canada.
| | - Carla G Taylor
- Department of Human Nutritional Sciences, University of Manitoba, 209 Human Ecology Building, Winnipeg, Manitoba R3T 292, Canada; Department of Physiology and Pathophysiology, University of Manitoba, 432 Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, Manitoba R3E 0J9, Canada; Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada.
| | - Peter Zahradka
- Department of Human Nutritional Sciences, University of Manitoba, 209 Human Ecology Building, Winnipeg, Manitoba R3T 292, Canada; Department of Physiology and Pathophysiology, University of Manitoba, 432 Basic Medical Sciences Building, 745 Bannatyne Avenue, Winnipeg, Manitoba R3E 0J9, Canada; Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, 351 Taché Avenue, Winnipeg, Manitoba R2H 2A6, Canada.
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Huang X, Lüthi M, Ontsouka EC, Kallol S, Baumann MU, Surbek DV, Albrecht C. Establishment of a confluent monolayer model with human primary trophoblast cells: novel insights into placental glucose transport. Mol Hum Reprod 2016; 22:442-56. [PMID: 26931579 DOI: 10.1093/molehr/gaw018] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 02/24/2016] [Indexed: 11/14/2022] Open
Abstract
STUDY HYPOTHESIS Using optimized conditions, primary trophoblast cells isolated from human term placenta can develop a confluent monolayer in vitro, which morphologically and functionally resembles the microvilli structure found in vivo. STUDY FINDING We report the successful establishment of a confluent human primary trophoblast monolayer using pre-coated polycarbonate inserts, where the integrity and functionality was validated by cell morphology, biophysical features, cellular marker expression and secretion, and asymmetric glucose transport. WHAT IS KNOWN ALREADY Human trophoblast cells form the initial barrier between maternal and fetal blood to regulate materno-fetal exchange processes. Although the method for isolating pure human cytotrophoblast cells was developed almost 30 years ago, a functional in vitro model with primary trophoblasts forming a confluent monolayer is still lacking. STUDY DESIGN, SAMPLES/MATERIALS, METHODS Human term cytotrophoblasts were isolated by enzymatic digestion and density gradient separation. The purity of the primary cells was evaluated by flow cytometry using the trophoblast-specific marker cytokeratin 7, and vimentin as an indicator for potentially contaminating cells. We screened different coating matrices for high cell viability to optimize the growth conditions for primary trophoblasts on polycarbonate inserts. During culture, cell confluency and polarity were monitored daily by determining transepithelial electrical resistance (TEER) and permeability properties of florescent dyes. The time course of syncytia-related gene expression and hCG secretion during syncytialization were assessed by quantitative RT-PCR and enzyme-linked immunosorbent assay, respectively. The morphology of cultured trophoblasts after 5 days was determined by light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Membrane makers were visualized using confocal microscopy. Additionally, glucose transport studies were performed on the polarized trophoblasts in the same system. MAIN RESULTS AND THE ROLE OF CHANCE During 5-day culture, the highly pure trophoblasts were cultured on inserts coated with reconstituted basement membrane matrix . They exhibited a confluent polarized monolayer, with a modest TEER and a size-dependent apparent permeability coefficient (Papp) to fluorescently labeled compounds (MW ∼400-70 000 Da). The syncytialization progress was characterized by gradually increasing mRNA levels of fusogen genes and elevating hCG secretion. SEM analyses confirmed a confluent trophoblast layer with numerous microvilli, and TEM revealed a monolayer with tight junctions. Immunocytochemistry on the confluent trophoblasts showed positivity for the cell-cell adhesion molecule E-cadherin, the tight junction protein 1 (ZO-1) and the membrane proteins ATP-binding cassette transporter A1 (ABCA1) and glucose transporter 1 (GLUT1). Applying this model to study the bidirectional transport of a non-metabolizable glucose derivative indicated a carrier-mediated placental glucose transport mechanism with asymmetric kinetics. LIMITATIONS, REASONS FOR CAUTION The current study is only focused on primary trophoblast cells isolated from healthy placentas delivered at term. It remains to be evaluated whether this system can be extended to pathological trophoblasts isolated from diverse gestational diseases. WIDER IMPLICATIONS OF THE FINDINGS These findings confirmed the physiological properties of the newly developed human trophoblast barrier, which can be applied to study the exchange of endobiotics and xenobiotics between the maternal and fetal compartment, as well as intracellular metabolism, paracellular contributions and regulatory mechanisms influencing the vectorial transport of molecules. LARGE-SCALE DATA Not applicable. STUDY FUNDING AND COMPETING INTERESTS This study was supported by the Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Switzerland, and the Swiss National Science Foundation (grant no. 310030_149958, C.A.). All authors declare that their participation in the study did not involve factual or potential conflicts of interests.
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Affiliation(s)
- Xiao Huang
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, CH-3012 Bern, Switzerland
| | - Michael Lüthi
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, CH-3012 Bern, Switzerland
| | - Edgar C Ontsouka
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, CH-3012 Bern, Switzerland
| | - Sampada Kallol
- Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, CH-3012 Bern, Switzerland
| | - Marc U Baumann
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland Department of Obstetrics and Gynecology, University Hospital, University of Bern, Bern, Switzerland
| | - Daniel V Surbek
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland Department of Obstetrics and Gynecology, University Hospital, University of Bern, Bern, Switzerland
| | - Christiane Albrecht
- Swiss National Center of Competence in Research, NCCR TransCure, University of Bern, Bern, Switzerland Institute of Biochemistry and Molecular Medicine, Faculty of Medicine, University of Bern, Buehlstrasse 28, CH-3012 Bern, Switzerland
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Vici P, Pizzuti L, Di Lauro L, Conti L, Mandoj C, Antenucci A, Digiesi G, Sergi D, Amodio A, Marchetti P, Sperati F, Valle M, Garofalo A, Vizza E, Corrado G, Vincenzoni C, Tomao F, Kayal R, Marsella A, Carosi M, Antoniani B, Giordano A, Maugeri-Saccà M, Barba M. Metabolic Determinants and Anthropometric Indicators Impact Clinical-pathological Features in Epithelial Ovarian Cancer Patients. J Cancer 2016; 7:516-22. [PMID: 26958087 PMCID: PMC4780127 DOI: 10.7150/jca.13578] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 12/08/2015] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Over the last twenty years, the efforts of the scientific community devoted to the comprehension and treatment of ovarian cancer have remained poorly remunerative, with the case-fatality ratio of this disease remaining disappointedly high. Limited knowledge of the basic principles regulating ovarian carcinogenesis and factors impacting the course of disease may significantly impair our ability to intervene in early stages and lessen our expectations in terms of treatment outcomes. In the present study, we sought to assess whether metabolic factors and anthropometric indicators, i.e., pre-treatment fasting glucose and body mass index, are associated with renown cancer related prognostic factors such as tumour stage and grade at diagnosis. MATERIALS AND METHODS Study participants were 147 women diagnosed with epithelial ovarian cancer and treated with platinum based regimens and/or surgery at the Regina Elena National Cancer Institute of Rome, Italy. Glucose levels were assessed at the institutional laboratories on venous blood collected in overnight fasting conditions and prior to any therapeutic procedure. Stage was coded according to the FIGO staging system based on the results of the diagnostic workup, while tumour grade was locally assessed by an expert pathologist. Participants' characteristics were descriptively analyzed for the overall study population and in a subgroup of 70 patients for whom data on body mass index (BMI) were available. FIGO stage and grade were compared by categories of pre-treatment fasting glucose defined upon the median value, i.e., 89 mg/dl. The association of interest was tested in regression models including BMI. RESULTS For the overall study population, patients in the lowest category of fasting glucose were significantly more likely to exhibit a FIGO stage III-IV at diagnosis compared with their counterpart in the highest glucose category (81.3 vs 66.7%, p: 0.021). Subgroup analysis in 70 patients with BMI data confirmed this association (81.5 vs 55.8, p: 0.049), which remained significant when tested in regression models including BMI (OR: 0.28 95% CI 0.086-0.89, p: 0.031). No relevant evidence emerged when testing the association between fasting glucose and tumour grade. CONCLUSIONS In patients diagnosed with epithelial ovarian cancer, pre-treatment glucose levels appear to be inversely associated with FIGO stage. Further studies are warranted to eventually confirm and correctly interpret the implications of this novel finding.
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Affiliation(s)
- Patrizia Vici
- 1. Division of Medical Oncology 2, Regina Elena National Cancer Institute, Rome, Italy
| | - Laura Pizzuti
- 1. Division of Medical Oncology 2, Regina Elena National Cancer Institute, Rome, Italy
| | - Luigi Di Lauro
- 1. Division of Medical Oncology 2, Regina Elena National Cancer Institute, Rome, Italy
| | - Laura Conti
- 2. Division of Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy
| | - Chiara Mandoj
- 2. Division of Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy
| | - Anna Antenucci
- 2. Division of Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy
| | - Giovanna Digiesi
- 2. Division of Clinical Pathology, Regina Elena National Cancer Institute, Rome, Italy
| | - Domenico Sergi
- 1. Division of Medical Oncology 2, Regina Elena National Cancer Institute, Rome, Italy
| | - Antonella Amodio
- 1. Division of Medical Oncology 2, Regina Elena National Cancer Institute, Rome, Italy
| | - Paolo Marchetti
- 3. Oncology Unit, Sant'Andrea Hospital, La Sapienza University of Rome, Italy
| | - Francesca Sperati
- 4. Biostatistics Unit-Scientific Direction, Regina Elena National Cancer Institute, Rome, Italy
| | - Mario Valle
- 5. General Surgery, Regina Elena National Institute, Rome, Italy
| | - Alfredo Garofalo
- 5. General Surgery, Regina Elena National Institute, Rome, Italy
| | - Enrico Vizza
- 6. Gynecological Oncology, Regina Elena National Cancer Institute, Rome, Italy
| | - Giacomo Corrado
- 6. Gynecological Oncology, Regina Elena National Cancer Institute, Rome, Italy
| | - Cristina Vincenzoni
- 6. Gynecological Oncology, Regina Elena National Cancer Institute, Rome, Italy
| | - Federica Tomao
- 7. Department of Gynecologic Oncology, University “Sapienza”, Viale del Policlinico 155, 00161 Rome, Italy
| | - Ramy Kayal
- 8. Department of Radiology, Regina Elena National Cancer Institute, Rome, Italy
| | - Annalise Marsella
- 8. Department of Radiology, Regina Elena National Cancer Institute, Rome, Italy
| | - Mariantonia Carosi
- 9. Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy
| | - Barbara Antoniani
- 9. Department of Pathology, Regina Elena National Cancer Institute, Rome, Italy
| | - Antonio Giordano
- 10. Sbarro Institute for Cancer Research and Molecular Medicine e del Center for Biotechnology, College of Science and Technology, Temple University, Philadelphia, PA, USA
- 11. Department of Medicine, Surgery and Neurosciences, University of Siena, Siena, Italy
| | - Marcello Maugeri-Saccà
- 1. Division of Medical Oncology 2, Regina Elena National Cancer Institute, Rome, Italy
- 12. Scientific Direction, Regina Elena National Cancer Institute, Rome, Italy
| | - Maddalena Barba
- 1. Division of Medical Oncology 2, Regina Elena National Cancer Institute, Rome, Italy
- 12. Scientific Direction, Regina Elena National Cancer Institute, Rome, Italy
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Kumar Kondapi VP, Soueidan OM, Hosseini SN, Jabari N, West FG. Efficient and Easy Access to Optically Pure Tetrasubstituted Tetrahydrofurans via Stereoselective Opening ofC2-Symmetric Epoxide and Aziridine Rings. European J Org Chem 2016. [DOI: 10.1002/ejoc.201501540] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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Glucose Transporters at the Blood-Brain Barrier: Function, Regulation and Gateways for Drug Delivery. Mol Neurobiol 2016; 54:1046-1077. [PMID: 26801191 DOI: 10.1007/s12035-015-9672-6] [Citation(s) in RCA: 204] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 12/17/2015] [Indexed: 12/31/2022]
Abstract
Glucose transporters (GLUTs) at the blood-brain barrier maintain the continuous high glucose and energy demands of the brain. They also act as therapeutic targets and provide routes of entry for drug delivery to the brain and central nervous system for treatment of neurological and neurovascular conditions and brain tumours. This article first describes the distribution, function and regulation of glucose transporters at the blood-brain barrier, the major ones being the sodium-independent facilitative transporters GLUT1 and GLUT3. Other GLUTs and sodium-dependent transporters (SGLTs) have also been identified at lower levels and under various physiological conditions. It then considers the effects on glucose transporter expression and distribution of hypoglycemia and hyperglycemia associated with diabetes and oxygen/glucose deprivation associated with cerebral ischemia. A reduction in glucose transporters at the blood-brain barrier that occurs before the onset of the main pathophysiological changes and symptoms of Alzheimer's disease is a potential causative effect in the vascular hypothesis of the disease. Mutations in glucose transporters, notably those identified in GLUT1 deficiency syndrome, and some recreational drug compounds also alter the expression and/or activity of glucose transporters at the blood-brain barrier. Approaches for drug delivery across the blood-brain barrier include the pro-drug strategy whereby drug molecules are conjugated to glucose transporter substrates or encapsulated in nano-enabled delivery systems (e.g. liposomes, micelles, nanoparticles) that are functionalised to target glucose transporters. Finally, the continuous development of blood-brain barrier in vitro models is important for studying glucose transporter function, effects of disease conditions and interactions with drugs and xenobiotics.
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81
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Stringer DM, Zahradka P, Taylor CG. Glucose transporters: cellular links to hyperglycemia in insulin resistance and diabetes. Nutr Rev 2016; 73:140-54. [PMID: 26024537 DOI: 10.1093/nutrit/nuu012] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Abnormal expression and/or function of mammalian hexose transporters contribute to the hallmark hyperglycemia of diabetes. Due to different roles in glucose handling, various organ systems possess specific transporters that may be affected during the diabetic state. Diabetes has been associated with higher rates of intestinal glucose transport, paralleled by increased expression of both active and facilitative transporters and a shift in the location of transporters within the enterocyte, events that occur independent of intestinal hyperplasia and hyperglycemia. Peripheral tissues also exhibit deregulated glucose transport in the diabetic state, most notably defective translocation of transporters to the plasma membrane and reduced capacity to clear glucose from the bloodstream. Expression of renal active and facilitative glucose transporters increases as a result of diabetes, leading to elevated rates of glucose reabsorption. However, this may be a natural response designed to combat elevated blood glucose concentrations and not necessarily a direct effect of insulin deficiency. Functional foods and nutraceuticals, by modulation of glucose transporter activity, represent a potential dietary tool to aid in the management of hyperglycemia and diabetes.
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Affiliation(s)
- Danielle M Stringer
- D.M. Stringer was with the Department of Human Nutritional Sciences, University of Manitoba, and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, MB, Canada at the time of manuscript preparation. C.G. Taylor is with the Department of Human Nutritional Sciences, University of Manitoba; the Department of Physiology, University of Manitoba; and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada. P. Zahradka is with the Department of Human Nutritional Sciences, University of Manitoba; the Department of Physiology, University of Manitoba; and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada.
| | - Peter Zahradka
- D.M. Stringer was with the Department of Human Nutritional Sciences, University of Manitoba, and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, MB, Canada at the time of manuscript preparation. C.G. Taylor is with the Department of Human Nutritional Sciences, University of Manitoba; the Department of Physiology, University of Manitoba; and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada. P. Zahradka is with the Department of Human Nutritional Sciences, University of Manitoba; the Department of Physiology, University of Manitoba; and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada
| | - Carla G Taylor
- D.M. Stringer was with the Department of Human Nutritional Sciences, University of Manitoba, and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, MB, Canada at the time of manuscript preparation. C.G. Taylor is with the Department of Human Nutritional Sciences, University of Manitoba; the Department of Physiology, University of Manitoba; and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada. P. Zahradka is with the Department of Human Nutritional Sciences, University of Manitoba; the Department of Physiology, University of Manitoba; and the Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Winnipeg, Manitoba, Canada
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82
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Sharawy MH, El-Awady MS, Megahed N, Gameil NM. The ergogenic supplement β-hydroxy-β-methylbutyrate (HMB) attenuates insulin resistance through suppressing GLUT-2 in rat liver. Can J Physiol Pharmacol 2015; 94:488-97. [PMID: 26871756 DOI: 10.1139/cjpp-2015-0385] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This study investigates the effect of the ergogenic supplement β-hydroxy-β-methylbutyrate (HMB) on insulin resistance induced by high-fructose diet (HFD) in rats. Male Sprague Dawley rats were fed 60% HFD for 12 weeks and HMB (320 mg·kg(-1)·day(-1), orally) for 4 weeks. HFD significantly increased fasting insulin, fasting glucose, glycosylated hemoglobin (HBA1C), liver glycogen content, and homeostasis model assessment of insulin resistance (HOMA-IR) index, while it decreased glucose and insulin tolerance. Furthermore, HFD significantly increased serum triglycerides (TG), low density lipoprotein cholesterol (LDL-C), and very low density lipoprotein cholesterol (VLDL-C) levels, while it significantly decreased high density lipoprotein cholesterol (HDL-C). Moreover, HFD significantly increased mRNA expression of glucose transporter type-2 (GLUT-2), the mammalian target of rapamycin (mTOR), and sterol regulatory element-binding protein-1c (SREBP-1c) but decreased peroxisome proliferator-activated receptor-alpha (PPAR-α) in liver. Aortic relaxation to acetylcholine (ACh) was impaired and histopathology showed severe hepatic steatosis. HMB significantly increased insulin tolerance and decreased fasting insulin, HOMA-IR, HBA1C, hepatic glycogen content, serum TG, LDL-C, and VLDL-C. Additionally, HMB enhanced ACh-induced relaxation, ameliorated hepatic steatosis, and decreased mRNA expression of GLUT-2. In conclusion, HMB may attenuate insulin resistance and hepatic steatosis through inhibiting GLUT-2 in liver.
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Affiliation(s)
- Maha H Sharawy
- a Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - Mohammed S El-Awady
- a Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
| | - Nirmeen Megahed
- b Department of Pathology, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Nariman M Gameil
- a Department of Pharmacology and Toxicology, Faculty of Pharmacy, Mansoura University, Mansoura 35516, Egypt
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83
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Ares GR, Ortiz PA. Direct renal effects of a fructose-enriched diet: interaction with high salt intake. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1078-81. [PMID: 26447210 DOI: 10.1152/ajpregu.00156.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Accepted: 09/30/2015] [Indexed: 01/12/2023]
Abstract
Consumption of fructose has increased during the last 50 years. Excessive fructose consumption has a detrimental effect on mammalian health but the mechanisms remain unclear. In humans, a direct relationship exists between dietary intake of added sugars and increased risk for cardiovascular disease mortality (52). While the causes for this are unclear, we recently showed that fructose provided in the drinking water induces a salt-dependent increase in blood pressure in Sprague-Dawley rats in a matter of days (6). However, little is known about the effects of fructose in renal salt handling and whether combined intake of high fructose and salt can lead to salt-sensitive hypertension before the development of metabolic abnormalities. The long-term (more than 4 wk) adverse effects of fructose intake on renal function are not just due to fructose but are also secondary to alterations in metabolism which may have an impact on renal function. This minireview focuses on the acute effect of fructose intake and its effect on salt regulation, as they affect blood pressure.
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Affiliation(s)
- Gustavo R Ares
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
| | - Pablo A Ortiz
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and Department of Physiology, Wayne State University, Detroit, Michigan
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84
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Patel C, Douard V, Yu S, Gao N, Ferraris RP. Transport, metabolism, and endosomal trafficking-dependent regulation of intestinal fructose absorption. FASEB J 2015; 29:4046-58. [PMID: 26071406 PMCID: PMC4550372 DOI: 10.1096/fj.15-272195] [Citation(s) in RCA: 66] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 06/02/2015] [Indexed: 01/03/2023]
Abstract
Dietary fructose that is linked to metabolic abnormalities can up-regulate its own absorption, but the underlying regulatory mechanisms are not known. We hypothesized that glucose transporter (GLUT) protein, member 5 (GLUT5) is the primary fructose transporter and that fructose absorption via GLUT5, metabolism via ketohexokinase (KHK), as well as GLUT5 trafficking to the apical membrane via the Ras-related protein-in-brain 11 (Rab11)a-dependent endosomes are each required for regulation. Introducing fructose but not lysine and glucose solutions into the lumen increased by 2- to 10-fold the heterogeneous nuclear RNA, mRNA, protein, and activity levels of GLUT5 in adult wild-type mice consuming chow. Levels of GLUT5 were >100-fold that of candidate apical fructose transporters GLUTs 7, 8, and 12 whose expression, and that of GLUT 2 and the sodium-dependent glucose transporter protein 1 (SGLT1), was not regulated by luminal fructose. GLUT5-knockout (KO) mice exhibited no facilitative fructose transport and no compensatory increases in activity and expression of SGLT1 and other GLUTs. Fructose could not up-regulate GLUT5 in GLUT5-KO, KHK-KO, and intestinal epithelial cell-specific Rab11a-KO mice. The fructose-specific metabolite glyceraldehyde did not increase GLUT5 expression. GLUT5 is the primary transporter responsible for facilitative absorption of fructose, and its regulation specifically requires fructose uptake and metabolism and normal GLUT5 trafficking to the apical membrane.
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Affiliation(s)
- Chirag Patel
- *Department of Pharmacology and Physiology, New Jersey Medical School, and Department of Biological Sciences, School of Arts and Sciences, Rutgers University, Newark, New Jersey, USA
| | - Veronique Douard
- *Department of Pharmacology and Physiology, New Jersey Medical School, and Department of Biological Sciences, School of Arts and Sciences, Rutgers University, Newark, New Jersey, USA
| | - Shiyan Yu
- *Department of Pharmacology and Physiology, New Jersey Medical School, and Department of Biological Sciences, School of Arts and Sciences, Rutgers University, Newark, New Jersey, USA
| | - Nan Gao
- *Department of Pharmacology and Physiology, New Jersey Medical School, and Department of Biological Sciences, School of Arts and Sciences, Rutgers University, Newark, New Jersey, USA
| | - Ronaldo P Ferraris
- *Department of Pharmacology and Physiology, New Jersey Medical School, and Department of Biological Sciences, School of Arts and Sciences, Rutgers University, Newark, New Jersey, USA
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85
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Deng D, Sun P, Yan C, Ke M, Jiang X, Xiong L, Ren W, Hirata K, Yamamoto M, Fan S, Yan N. Molecular basis of ligand recognition and transport by glucose transporters. Nature 2015; 526:391-6. [DOI: 10.1038/nature14655] [Citation(s) in RCA: 255] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2015] [Accepted: 06/12/2015] [Indexed: 01/20/2023]
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86
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Rosendale AJ, Lee RE, Costanzo JP. Seasonal variation and freezing response of glucose transporter 2 in liver of the wood frog: implications for geographic variation in freeze tolerance. J Zool (1987) 2015. [DOI: 10.1111/jzo.12255] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
| | - R. E. Lee
- Department of Zoology; Miami University; Oxford OH USA
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87
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Pujol-Giménez J, Pérez A, Reyes AM, Loo DDF, Lostao MP. Functional characterization of the human facilitative glucose transporter 12 (GLUT12) by electrophysiological methods. Am J Physiol Cell Physiol 2015; 308:C1008-22. [PMID: 25855082 DOI: 10.1152/ajpcell.00343.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 04/06/2015] [Indexed: 12/11/2022]
Abstract
GLUT12 is a member of the facilitative family of glucose transporters. The goal of this study was to characterize the functional properties of GLUT12, expressed in Xenopus laevis oocytes, using radiotracer and electrophysiological methods. Our results showed that GLUT12 is a facilitative sugar transporter with substrate selectivity: d-glucose ≥ α-methyl-d-glucopyranoside (α-MG) > 2-deoxy-d-glucose(2-DOG) > d-fructose = d-galactose. α-MG is a characteristic substrate of the Na(+)/glucose (SGLT) family and has not been shown to be a substrate of any of the GLUTs. In the absence of sugar, (22)Na(+) was transported through GLUT12 at a higher rate (40%) than noninjected oocytes, indicating that there is a Na(+) leak through GLUT12. Genistein, an inhibitor of GLUT1, also inhibited sugar uptake by GLUT12. Glucose uptake was increased by the PKA activator 8-bromoadenosine 3',5'-cyclic monophosphate (8-Br-cAMP) but not by the PKC activator phorbol-12-myristate-13-acetate (PMA). In high K(+) concentrations, glucose uptake was blocked. Addition of glucose to the external solution induced an inward current with a reversal potential of approximately -15 mV and was blocked by Cl(-) channel blockers, indicating the current was carried by Cl(-) ions. The sugar-activated Cl(-) currents were unaffected by genistein. In high external K(+) concentrations, sugar-activated Cl(-) currents were also blocked, indicating that GLUT12 activity is voltage dependent. Furthermore, glucose-induced current was increased by the PKA activator 8-Br-cAMP but not by the PKC activator PMA. These new features of GLUT12 are very different from those described for other GLUTs, indicating that GLUT12 must have a specific physiological role within glucose homeostasis, still to be discovered.
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Affiliation(s)
- Jonai Pujol-Giménez
- Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, Pamplona, Spain
| | - Alejandra Pérez
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile; and
| | - Alejandro M Reyes
- Instituto de Bioquímica y Microbiología, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile; and
| | - Donald D F Loo
- Department of Physiology, David Geffen School of Medicine at University of California, Los Angeles, California
| | - Maria Pilar Lostao
- Department of Nutrition, Food Science and Physiology, School of Pharmacy, University of Navarra, Pamplona, Spain;
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88
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Mishra RK, Wei C, Hresko RC, Bajpai R, Heitmeier M, Matulis SM, Nooka AK, Rosen ST, Hruz PW, Schiltz GE, Shanmugam M. In Silico Modeling-based Identification of Glucose Transporter 4 (GLUT4)-selective Inhibitors for Cancer Therapy. J Biol Chem 2015; 290:14441-53. [PMID: 25847249 DOI: 10.1074/jbc.m114.628826] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2014] [Indexed: 12/14/2022] Open
Abstract
Tumor cells rely on elevated glucose consumption and metabolism for survival and proliferation. Glucose transporters mediating glucose entry are key proximal rate-limiting checkpoints. Unlike GLUT1 that is highly expressed in cancer and more ubiquitously expressed in normal tissues, GLUT4 exhibits more limited normal expression profiles. We have previously determined that insulin-responsive GLUT4 is constitutively localized on the plasma membrane of myeloma cells. Consequently, suppression of GLUT4 or inhibition of glucose transport with the HIV protease inhibitor ritonavir elicited growth arrest and/or apoptosis in multiple myeloma. GLUT4 inhibition also caused sensitization to metformin in multiple myeloma and chronic lymphocytic leukemia and a number of solid tumors suggesting the broader therapeutic utility of targeting GLUT4. This study sought to identify selective inhibitors of GLUT4 to develop a more potent cancer chemotherapeutic with fewer potential off-target effects. Recently, the crystal structure of GLUT1 in an inward open conformation was reported. Although this is an important achievement, a full understanding of the structural biology of facilitative glucose transport remains elusive. To date, there is no three-dimensional structure for GLUT4. We have generated a homology model for GLUT4 that we utilized to screen for drug-like compounds from a library of 18 million compounds. Despite 68% homology between GLUT1 and GLUT4, our virtual screen identified two potent compounds that were shown to target GLUT4 preferentially over GLUT1 and block glucose transport. Our results strongly bolster the utility of developing GLUT4-selective inhibitors as anti-cancer therapeutics.
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Affiliation(s)
- Rama K Mishra
- From the Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208
| | - Changyong Wei
- the Department of Hematology and Medical Oncology, School of Medicine, Emory University, Atlanta, Georgia 30322
| | - Richard C Hresko
- the Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Richa Bajpai
- the Department of Hematology and Medical Oncology, School of Medicine, Emory University, Atlanta, Georgia 30322
| | - Monique Heitmeier
- the Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Shannon M Matulis
- the Department of Hematology and Medical Oncology, School of Medicine, Emory University, Atlanta, Georgia 30322
| | - Ajay K Nooka
- the Department of Hematology and Medical Oncology, School of Medicine, Emory University, Atlanta, Georgia 30322
| | | | - Paul W Hruz
- the Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Gary E Schiltz
- From the Center for Molecular Innovation and Drug Discovery, Northwestern University, Evanston, Illinois 60208
| | - Mala Shanmugam
- the Department of Hematology and Medical Oncology, School of Medicine, Emory University, Atlanta, Georgia 30322
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89
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Muhič M, Vardjan N, Chowdhury HH, Zorec R, Kreft M. Insulin and Insulin-like Growth Factor 1 (IGF-1) Modulate Cytoplasmic Glucose and Glycogen Levels but Not Glucose Transport across the Membrane in Astrocytes. J Biol Chem 2015; 290:11167-76. [PMID: 25792745 DOI: 10.1074/jbc.m114.629063] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 01/21/2023] Open
Abstract
Astrocytes contain glycogen, an energy buffer, which can bridge local short term energy requirements in the brain. Glycogen levels reflect a dynamic equilibrium between glycogen synthesis and glycogenolysis. Many factors that include hormones and neuropeptides, such as insulin and insulin-like growth factor 1 (IGF-1) likely modulate glycogen stores in astrocytes, but detailed mechanisms at the cellular level are sparse. We used a glucose nanosensor based on Förster resonance energy transfer to monitor cytosolic glucose concentration with high temporal resolution and a cytochemical approach to determine glycogen stores in single cells. The results show that after glucose depletion, glycogen stores are replenished. Insulin and IGF-1 boost the process of glycogen formation. Although astrocytes appear to express glucose transporter GLUT4, glucose entry across the astrocyte plasma membrane is not affected by insulin. Stimulation of cells with insulin and IGF-1 decreased cytosolic glucose concentration, likely because of elevated glucose utilization for glycogen synthesis.
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Affiliation(s)
- Marko Muhič
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia
| | - Nina Vardjan
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia, Celica Biomedical, 1000 Ljubljana, Slovenia, and
| | - Helena H Chowdhury
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia, Celica Biomedical, 1000 Ljubljana, Slovenia, and
| | - Robert Zorec
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia, Celica Biomedical, 1000 Ljubljana, Slovenia, and
| | - Marko Kreft
- From the Laboratory of Neuroendocrinology-Molecular Cell Physiology, Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, Zaloška 4, 1000 Ljubljana, Slovenia, Celica Biomedical, 1000 Ljubljana, Slovenia, and the Department of Biology, Biotechnical Faculty, University of Ljubljana, Večna pot 111, 1000 Ljubljana, Slovenia
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90
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Gray CW, Coster ACF. A receptor state space model of the insulin signalling system in glucose transport. MATHEMATICAL MEDICINE AND BIOLOGY-A JOURNAL OF THE IMA 2015; 32:457-73. [PMID: 25673317 DOI: 10.1093/imammb/dqv003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 01/10/2015] [Indexed: 11/13/2022]
Abstract
Insulin is a potent peptide hormone that regulates glucose levels in the blood. Insulin-sensitive cells respond to insulin stimulation with the translocation of glucose transporter 4 (GLUT4) to the plasma membrane (PM), enabling the clearance of glucose from the blood. Defects in this process can give rise to insulin resistance and ultimately diabetes. One widely cited model of insulin signalling leading to glucose transport is that of Sedaghat et al. (2002) Am. J. Physiol. Endocrinol. Metab. 283, E1084-E1101. Consisting of 20 deterministic ordinary differential equations (ODEs), it is the most comprehensive model of insulin signalling to date. However, the model possesses some major limitations, including the non-conservation of key components. In the current work, we detail mathematical and sensitivity analyses of the Sedaghat model. Based on the results of these analyses, we propose a reduced state space model of the insulin receptor subsystem. This reduced model maintains the input-output relation of the original model but is computationally more efficient, analytically tractable and resolves some of the limitations of the Sedaghat model.
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Affiliation(s)
- Catheryn W Gray
- School of Mathematics and Statistics, UNSW Australia, Sydney, New South Wales, Australia
| | - Adelle C F Coster
- School of Mathematics and Statistics, UNSW Australia, Sydney, New South Wales, Australia
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91
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Garnett JP, Braun D, McCarthy AJ, Farrant MR, Baker EH, Lindsay JA, Baines DL. Fructose transport-deficient Staphylococcus aureus reveals important role of epithelial glucose transporters in limiting sugar-driven bacterial growth in airway surface liquid. Cell Mol Life Sci 2014; 71:4665-73. [PMID: 24810961 PMCID: PMC4232747 DOI: 10.1007/s00018-014-1635-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/11/2014] [Accepted: 04/28/2014] [Indexed: 02/05/2023]
Abstract
Hyperglycaemia as a result of diabetes mellitus or acute illness is associated with increased susceptibility to respiratory infection with Staphylococcus aureus. Hyperglycaemia increases the concentration of glucose in airway surface liquid (ASL) and promotes the growth of S. aureus in vitro and in vivo. Whether elevation of other sugars in the blood, such as fructose, also results in increased concentrations in ASL is unknown and whether sugars in ASL are directly utilised by S. aureus for growth has not been investigated. We obtained mutant S. aureus JE2 strains with transposon disrupted sugar transport genes. NE768(fruA) exhibited restricted growth in 10 mM fructose. In H441 airway epithelial-bacterial co-culture, elevation of basolateral sugar concentration (5-20 mM) increased the apical growth of JE2. However, sugar-induced growth of NE768(fruA) was significantly less when basolateral fructose rather than glucose was elevated. This is the first experimental evidence to show that S. aureus directly utilises sugars present in the ASL for growth. Interestingly, JE2 growth was promoted less by glucose than fructose. Net transepithelial flux of D-glucose was lower than D-fructose. However, uptake of D-glucose was higher than D-fructose across both apical and basolateral membranes consistent with the presence of GLUT1/10 in the airway epithelium. Therefore, we propose that the preferential uptake of glucose (compared to fructose) limits its accumulation in ASL. Pre-treatment with metformin increased transepithelial resistance and reduced the sugar-dependent growth of S. aureus. Thus, epithelial paracellular permeability and glucose transport mechanisms are vital to maintain low glucose concentration in ASL and limit bacterial nutrient sources as a defence against infection.
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Affiliation(s)
- James P. Garnett
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Daniela Braun
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Alex J. McCarthy
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Matthew R. Farrant
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Emma H. Baker
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Jodi A. Lindsay
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
| | - Deborah L. Baines
- Institute for Infection and Immunity, St George’s, University of London, Tooting, London, SW17 0RE UK
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92
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Saitoh S, Mori A, Uehara L, Masuda F, Soejima S, Yanagida M. Mechanisms of expression and translocation of major fission yeast glucose transporters regulated by CaMKK/phosphatases, nuclear shuttling, and TOR. Mol Biol Cell 2014; 26:373-86. [PMID: 25411338 PMCID: PMC4294683 DOI: 10.1091/mbc.e14-11-1503] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Glucose transporters play a pivotal role in glucose homeostasis. The fission yeast high-affinity glucose transporter Ght5 is regulated with regard to transcription and localization via CaMKK and TOR pathways. These results clarify the evolutionarily conserved mechanisms underlying glucose homeostasis that prevent hyperglycemia in humans. Hexose transporters are required for cellular glucose uptake; thus they play a pivotal role in glucose homeostasis in multicellular organisms. Using fission yeast, we explored hexose transporter regulation in response to extracellular glucose concentrations. The high-affinity transporter Ght5 is regulated with regard to transcription and localization, much like the human GLUT transporters, which are implicated in diabetes. When restricted to a glucose concentration equivalent to that of human blood, the fission yeast transcriptional regulator Scr1, which represses Ght5 transcription in the presence of high glucose, is displaced from the nucleus. Its displacement is dependent on Ca2+/calmodulin-dependent kinase kinase, Ssp1, and Sds23 inhibition of PP2A/PP6-like protein phosphatases. Newly synthesized Ght5 locates preferentially at the cell tips with the aid of the target of rapamycin (TOR) complex 2 signaling. These results clarify the evolutionarily conserved molecular mechanisms underlying glucose homeostasis, which are essential for preventing hyperglycemia in humans.
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Affiliation(s)
- Shigeaki Saitoh
- Institute of Life Science, Kurume University, Hyakunen-Kohen 1-1, Kurume, Fukuoka 839-0864, Japan
| | - Ayaka Mori
- Okinawa Institute Science and Technology Graduate University, Tancha 1919-1, Onna, Okinawa 904-0495, Japan
| | - Lisa Uehara
- Okinawa Institute Science and Technology Graduate University, Tancha 1919-1, Onna, Okinawa 904-0495, Japan
| | - Fumie Masuda
- Institute of Life Science, Kurume University, Hyakunen-Kohen 1-1, Kurume, Fukuoka 839-0864, Japan
| | - Saeko Soejima
- Institute of Life Science, Kurume University, Hyakunen-Kohen 1-1, Kurume, Fukuoka 839-0864, Japan
| | - Mitsuhiro Yanagida
- Okinawa Institute Science and Technology Graduate University, Tancha 1919-1, Onna, Okinawa 904-0495, Japan
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93
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Qian Y, Wang X, Chen X. Inhibitors of glucose transport and glycolysis as novel anticancer therapeutics. World J Transl Med 2014; 3:37-57. [DOI: 10.5528/wjtm.v3.i2.37] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Revised: 03/25/2014] [Accepted: 05/29/2014] [Indexed: 02/06/2023] Open
Abstract
Metabolic reprogramming and altered energetics have become an emerging hallmark of cancer and an active area of basic, translational, and clinical cancer research in the recent decade. Development of effective anticancer therapeutics may depend on improved understanding of the altered cancer metabolism compared to that of normal cells. Changes in glucose transport and glycolysis, which are drastically upregulated in most cancers and termed the Warburg effect, are one of major focuses of this new research area. By taking advantage of the new knowledge and understanding of cancer’s mechanisms, numerous therapeutic agents have been developed to target proteins and enzymes involved in glucose transport and metabolism, with promising results in cancer cells, animal tumor models and even clinical trials. It has also been hypothesized that targeting a pathway or a process, such as glucose transport or glucose metabolism, rather than a specific protein or enzyme in a signaling pathway may be more effective. This is based on the observation that cancer somehow can always bypass the inhibition of a target drug by switching to a redundant or compensatory pathway. In addition, cancer cells have higher dependence on glucose. This review will provide background information on glucose transport and metabolism in cancer, and summarize new therapeutic developments in basic and translational research in these areas, with a focus on glucose transporter inhibitors and glycolysis inhibitors. The daunting challenges facing both basic and clinical researchers of the field are also presented and discussed.
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94
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Price DRG, Gatehouse JA. Genome-wide annotation and functional identification of aphid GLUT-like sugar transporters. BMC Genomics 2014; 15:647. [PMID: 25091229 PMCID: PMC4132908 DOI: 10.1186/1471-2164-15-647] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Accepted: 06/13/2014] [Indexed: 11/10/2022] Open
Abstract
Background Phloem feeding insects, such as aphids, feed almost continuously on plant phloem sap, a liquid diet that contains high concentrations of sucrose (a disaccharide comprising of glucose and fructose). To access the available carbon, aphids hydrolyze sucrose in the gut lumen and transport its constituent monosaccharides, glucose and fructose. Although sugar transport plays a critical role in aphid nutrition, the molecular basis of sugar transport in aphids, and more generally across all insects, remains poorly characterized. Here, using the latest release of the pea aphid, Acyrthosiphon pisum, genome we provide an updated gene annotation and expression profile of putative sugar transporters. Finally, gut expressed sugar transporters are functionally expressed in yeast and screened for glucose and fructose transport activity. Results In this study, using a de novo approach, we identified 19 sugar porter (SP) family transporters in the A. pisum genome. Gene expression analysis, based on 214, 834 A. pisum expressed sequence tags, supports 17 sugar porter family transporters being actively expressed in adult female aphids. Further analysis, using quantitative PCR identifies 4 transporters, A. pisum sugar transporter 1, 3, 4 and 9 (ApST1, ApST3, ApST4 and ApST9) as highly expressed and/or enriched in gut tissue. When expressed in a Saccharomyces cerevisiae hexose transporter deletion mutant (strain EBY.VW4000), only ApST3 (previously characterized) and ApST4 (reported here) transport glucose and fructose resulting in functional rescue of the yeast mutant. Here we characterize ApST4, a 491 amino acid protein, with 12 predicted transmembrane regions, as a facilitative glucose/fructose transporter. Finally, phylogenetic reconstruction reveals that ApST4, and related, as yet uncharacterized insect transporters are phylogenetically closely related to human GLUT (SLC2A) class I facilitative glucose/fructose transporters. Conclusions The gut enhanced expression of ApST4, and the transport specificity of its product is consistent with ApST4 functioning as a gut glucose/fructose transporter. Here, we hypothesize that both ApST3 (reported previously) and ApST4 (reported here) function at the gut interface to import glucose and fructose from the gut lumen. Electronic supplementary material The online version of this article (doi:10.1186/1471-2164-15-647) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Daniel R G Price
- School of Biological and Biomedical Sciences, Durham University, South Road, Durham DH1 3LE, UK.
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95
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Lyons JA, Parker JL, Solcan N, Brinth A, Li D, Shah STA, Caffrey M, Newstead S. Structural basis for polyspecificity in the POT family of proton-coupled oligopeptide transporters. EMBO Rep 2014; 15:886-93. [PMID: 24916388 PMCID: PMC4149780 DOI: 10.15252/embr.201338403] [Citation(s) in RCA: 85] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
An enigma in the field of peptide transport is the structural basis for ligand promiscuity, as exemplified by PepT1, the mammalian plasma membrane peptide transporter. Here, we present crystal structures of di- and tripeptide-bound complexes of a bacterial homologue of PepT1, which reveal at least two mechanisms for peptide recognition that operate within a single, centrally located binding site. The dipeptide was orientated laterally in the binding site, whereas the tripeptide revealed an alternative vertical binding mode. The co-crystal structures combined with functional studies reveal that biochemically distinct peptide-binding sites likely operate within the POT/PTR family of proton-coupled symporters and suggest that transport promiscuity has arisen in part through the ability of the binding site to accommodate peptides in multiple orientations for transport.
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Affiliation(s)
- Joseph A Lyons
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Joanne L Parker
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Nicolae Solcan
- Department of Biochemistry, University of Oxford, Oxford, UK
| | - Alette Brinth
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Dianfan Li
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Syed T A Shah
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Martin Caffrey
- Schools of Medicine and Biochemistry & Immunology, Trinity College Dublin, Dublin, Ireland
| | - Simon Newstead
- Department of Biochemistry, University of Oxford, Oxford, UK
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96
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Zhang S, Zuo W, Guo XF, He WB, Chen NH. Cerebral glucose transporter: The possible therapeutic target for ischemic stroke. Neurochem Int 2014; 70:22-9. [DOI: 10.1016/j.neuint.2014.03.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Revised: 03/02/2014] [Accepted: 03/08/2014] [Indexed: 02/01/2023]
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97
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Nishizawa T, Kanter JE, Kramer F, Barnhart S, Shen X, Vivekanandan-Giri A, Wall VZ, Kowitz J, Devaraj S, O'Brien KD, Pennathur S, Tang J, Miyaoka RS, Raines EW, Bornfeldt KE. Testing the role of myeloid cell glucose flux in inflammation and atherosclerosis. Cell Rep 2014; 7:356-365. [PMID: 24726364 DOI: 10.1016/j.celrep.2014.03.028] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 02/26/2014] [Accepted: 03/11/2014] [Indexed: 10/25/2022] Open
Abstract
Inflammatory activation of myeloid cells is accompanied by increased glycolysis, which is required for the surge in cytokine production. Although in vitro studies suggest that increased macrophage glucose metabolism is sufficient for cytokine induction, the proinflammatory effects of increased myeloid cell glucose flux in vivo and the impact on atherosclerosis, a major complication of diabetes, are unknown. We therefore tested the hypothesis that increased glucose uptake in myeloid cells stimulates cytokine production and atherosclerosis. Overexpression of the glucose transporter GLUT1 in myeloid cells caused increased glycolysis and flux through the pentose phosphate pathway but did not induce cytokines. Moreover, myeloid-cell-specific overexpression of GLUT1 in LDL receptor-deficient mice was ineffective in promoting atherosclerosis. Thus, increased glucose flux is insufficient for inflammatory myeloid cell activation and atherogenesis. If glucose promotes atherosclerosis by increasing cellular glucose flux, myeloid cells do not appear to be the key targets.
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Affiliation(s)
- Tomohiro Nishizawa
- Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Jenny E Kanter
- Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Farah Kramer
- Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Shelley Barnhart
- Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Xia Shen
- Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | | | - Valerie Z Wall
- Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Jason Kowitz
- Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | - Sridevi Devaraj
- Baylor College of Medicine, Houston, TX 77030, USA; Texas Children's Hospital, Houston, TX 77030, USA
| | - Kevin D O'Brien
- Department of Medicine, University of Washington, Seattle, WA 98109, USA
| | | | - Jingjing Tang
- Department of Pathology, University of Washington, Seattle, WA 98109, USA
| | - Robert S Miyaoka
- Department of Radiology, University of Washington, Seattle, WA 98195, USA
| | - Elaine W Raines
- Department of Pathology, University of Washington, Seattle, WA 98109, USA
| | - Karin E Bornfeldt
- Diabetes and Obesity Center of Excellence, University of Washington, Seattle, WA 98109, USA; Department of Medicine, University of Washington, Seattle, WA 98109, USA; Department of Pathology, University of Washington, Seattle, WA 98109, USA.
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98
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Douard V, Patel C, Lee J, Tharabenjasin P, Williams E, Fritton JC, Sabbagh Y, Ferraris RP. Chronic high fructose intake reduces serum 1,25 (OH)2D3 levels in calcium-sufficient rodents. PLoS One 2014; 9:e93611. [PMID: 24718641 PMCID: PMC3981704 DOI: 10.1371/journal.pone.0093611] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Accepted: 03/05/2014] [Indexed: 12/14/2022] Open
Abstract
Excessive fructose consumption inhibits adaptive increases in intestinal Ca2+ transport in lactating and weanling rats with increased Ca2+ requirements by preventing the increase in serum levels of 1,25(OH)2D3. Here we tested the hypothesis that chronic fructose intake decreases 1,25(OH)2D3 levels independent of increases in Ca2+ requirements. Adult mice fed for five wk a high glucose-low Ca2+ diet displayed expected compensatory increases in intestinal and renal Ca2+ transporter expression and activity, in renal CYP27B1 (coding for 1α-hydroxylase) expression as well as in serum 1,25(OH)2D3 levels, compared with mice fed isocaloric glucose- or fructose-normal Ca2+ diets. Replacing glucose with fructose prevented these increases in Ca2+ transporter, CYP27B1, and 1,25(OH)2D3 levels induced by a low Ca2+ diet. In adult mice fed for three mo a normal Ca2+ diet, renal expression of CYP27B1 and of CYP24A1 (24-hydroxylase) decreased and increased, respectively, when the carbohydrate source was fructose instead of glucose or starch. Intestinal and renal Ca2+ transporter activity and expression did not vary with dietary carbohydrate. To determine the time course of fructose effects, a high fructose or glucose diet with normal Ca2+ levels was fed to adult rats for three mo. Serum levels of 1,25(OH)2D3 decreased and of FGF23 increased significantly over time. Renal expression of CYP27B1 and serum levels of 1,25(OH)2D3 still decreased in fructose- compared to those in glucose-fed rats after three mo. Serum parathyroid hormone, Ca2+ and phosphate levels were normal and independent of dietary sugar as well as time of feeding. Thus, chronically high fructose intakes can decrease serum levels of 1,25(OH)2D3 in adult rodents experiencing no Ca2+ stress and fed sufficient levels of dietary Ca2+. This finding is highly significant because fructose constitutes a substantial portion of the average diet of Americans already deficient in vitamin D.
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Affiliation(s)
- Veronique Douard
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers Biomedical and Health Sciences (RBHS), Newark, New Jersey, United States of America
- * E-mail:
| | - Chirag Patel
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers Biomedical and Health Sciences (RBHS), Newark, New Jersey, United States of America
| | - Jacklyn Lee
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers Biomedical and Health Sciences (RBHS), Newark, New Jersey, United States of America
| | - Phuntila Tharabenjasin
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers Biomedical and Health Sciences (RBHS), Newark, New Jersey, United States of America
| | - Edek Williams
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey, United States of America
| | - J. Christopher Fritton
- Department of Biomedical Engineering, Rutgers University, Piscataway, New Jersey, United States of America
- Department of Orthopaedics, New Jersey Medical School, RBHS, Newark, New Jersey, United States of America
| | - Yves Sabbagh
- Tissue Protection and Repair, Sanofi-Genzyme R&D Center, Genzyme, a Sanofi Company, Framingham, Massachusetts, United States of America
| | - Ronaldo P. Ferraris
- Department of Pharmacology and Physiology, New Jersey Medical School, Rutgers Biomedical and Health Sciences (RBHS), Newark, New Jersey, United States of America
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99
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Tharabenjasin P, Douard V, Patel C, Krishnamra N, Johnson RJ, Zuo J, Ferraris RP. Acute interactions between intestinal sugar and calcium transport in vitro. Am J Physiol Gastrointest Liver Physiol 2014; 306:G1-12. [PMID: 24177030 DOI: 10.1152/ajpgi.00263.2013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fructose consumption by Americans has increased markedly, whereas Ca(2+) intake has decreased below recommended levels. Because fructose metabolism decreases enterocyte ATP concentrations, we tested the hypothesis that luminal fructose acutely reduces active, diet-inducible Ca(2+) transport in the small intestine. We confirmed that the decrease in ATP concentrations was indeed greater in fructose- compared with glucose-incubated mucosal homogenates from wild-type and was prevented in fructose-incubated homogenates from ketohexokinase (KHK)(-/-) mice. We then induced active Ca(2+) transport by chronically feeding wild-type, fructose transporter glucose transporter 5 (GLUT5)(-/-), as well as KHK(-/-) mice a low Ca(2+) diet and measured transepithelial Ca(2+) transport in everted duodenal sacs incubated in solutions containing glucose, fructose, or their nonmetabolizable analogs. The diet-induced increase in active Ca(2+) transport was proportional to dramatic increases in expression of the Ca(2+)-selective channel transient receptor potential vanilloid family calcium channel 6 as well as of the Ca(2+)-binding protein 9k (CaBP9k) but not that of the voltage-dependent L-type channel Ca(v)1.3. Crypt-villus distribution of CaBP9k seems heterogeneous, but low Ca(2+) diets induce expression in more cells. In contrast, KHK distribution is homogeneous, suggesting that fructose metabolism can occur in all enterocytes. Diet-induced Ca(2+) transport was not enhanced by addition of the enterocyte fuel glutamine and was always greater in sacs of wild-type, GLUT5(-/-), and KHK(-/-) mice incubated with fructose or nonmetabolizable sugars than those incubated with glucose. Thus duodenal Ca(2+) transport is not affected by fructose and enterocyte ATP concentrations but instead may decrease with glucose metabolism, as Ca(2+) transport remains high with 3-O-methylglucose that is also transported by sodium-glucose cotransporter 1 but cannot be metabolized.
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Affiliation(s)
- Phuntila Tharabenjasin
- Dept. of Pharmacology & Physiology, Rutgers Biomedical and Health Sciences, New Jersey Medical School (NJMS 185 South Orange Ave., Newark, NJ 07103.
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100
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Stock M, Gretscher RR, Groth M, Eiserloh S, Boland W, Burse A. Putative sugar transporters of the mustard leaf beetle Phaedon cochleariae: their phylogeny and role for nutrient supply in larval defensive glands. PLoS One 2013; 8:e84461. [PMID: 24391959 PMCID: PMC3877287 DOI: 10.1371/journal.pone.0084461] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Accepted: 11/22/2013] [Indexed: 01/31/2023] Open
Abstract
Background Phytophagous insects have emerged successfully on the planet also because of the development of diverse and often astonishing defensive strategies against their enemies. The larvae of the mustard leaf beetle Phaedon cochleariae, for example, secrete deterrents from specialized defensive glands on their back. The secretion process involves ATP-binding cassette transporters. Therefore, sugar as one of the major energy sources to fuel the ATP synthesis for the cellular metabolism and transport processes, has to be present in the defensive glands. However, the role of sugar transporters for the production of defensive secretions was not addressed until now. Results To identify sugar transporters in P. cochleariae, a transcript catalogue was created by Illumina sequencing of cDNA libraries. A total of 68,667 transcripts were identified and 68 proteins were annotated as either members of the solute carrier 2 (SLC2) family or trehalose transporters. Phylogenetic analyses revealed an extension of the mammalian GLUT6/8 class in insects as well as one group of transporters exhibiting distinctive conserved motifs only present in the insect order Coleoptera. RNA-seq data of samples derived from the defensive glands revealed six transcripts encoding sugar transporters with more than 3,000 counts. Two of them are exclusively expressed in the glandular tissue. Reduction in secretions production was accomplished by silencing two of four selected transporters. RNA-seq experiments of transporter-silenced larvae showed the down-regulation of the silenced transporter but concurrently the up-regulation of other SLC2 transporters suggesting an adaptive system to maintain sugar homeostasis in the defensive glands. Conclusion We provide the first comprehensive phylogenetic study of the SLC2 family in a phytophagous beetle species. RNAi and RNA-seq experiments underline the importance of SLC2 transporters in defensive glands to achieve a chemical defense for successful competitive interaction in natural ecosystems.
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Affiliation(s)
- Magdalena Stock
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena, Thuringia, Germany
| | - René R Gretscher
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena, Thuringia, Germany
| | - Marco Groth
- Genome Analysis Group, Leibniz Institute for Age Research - Fritz Lipmann Institute, Jena, Thuringia, Germany
| | - Simone Eiserloh
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena, Thuringia, Germany
| | - Wilhelm Boland
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena, Thuringia, Germany
| | - Antje Burse
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Jena, Thuringia, Germany
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