1
|
Gil-Iturbe E, Castilla-Madrigal R, Barrenetxe J, Villaro AC, Lostao MP. GLUT12 expression and regulation in murine small intestine and human Caco-2 cells. J Cell Physiol 2018; 234:4396-4408. [PMID: 30352123 DOI: 10.1002/jcp.27231] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Accepted: 07/17/2018] [Indexed: 12/17/2022]
Abstract
GLUT12 was cloned from the mammary cancer cell line MCF-7, but its physiological role still needs to be elucidated. To gain more knowledge of GLUT12 function in the intestine, we investigated GLUT12 subcellular localization in the small intestine and its regulation by sugars, hormones, and intracellular mediators in Caco-2 cells and mice. Immunohistochemical methods were used to determine GLUT12 subcellular localization in human and murine small intestine. Brush border membrane vesicles were isolated for western blot analyses. Functional studies were performed in Caco-2 cells by measuring α-methyl-d-glucose (αMG) uptake in the absence of sodium. GLUT12 is located in the apical cytoplasm, below the brush border membrane, and in the perinuclear region of murine and human enterocytes. In Caco-2 cells, GLUT12 translocation to the apical membrane and α-methyl- d-glucose uptake by the transporter are stimulated by protons, glucose, insulin, tumor necrosis factor-α (TNF-α), protein kinase C, and AMP-activated protein kinase. In contrast, hypoxia decreases GLUT12 expression in the apical membrane. Upregulation of TNF-α and hypoxia-inducible factor-1α ( HIF-1α) genes is found in the jejunal mucosa of diet-induced obese mice. In these animals, GLUT12 expression in the brush border membrane is slightly decreased compared with lean animals. Moreover, an intraperitoneal injection of insulin does not induce GLUT12 translocation to the membrane, as it occurs in lean animals. GLUT12 rapid translocation to the enterocytes' apical membrane in response to glucose and insulin could be related to GLUT12 participation in sugar absorption during postprandial periods. In obesity, in which insulin sensitivity is reduced, the contribution of GLUT12 to sugar absorption is affected.
Collapse
Affiliation(s)
- Eva Gil-Iturbe
- Department of Nutrition, Food Science and Physiology, University of Navarra, Pamplona, Spain.,Nutrition Research Centre, University of Navarra, Pamplona, Spain
| | - Rosa Castilla-Madrigal
- Department of Nutrition, Food Science and Physiology, University of Navarra, Pamplona, Spain.,Nutrition Research Centre, University of Navarra, Pamplona, Spain
| | - Jaione Barrenetxe
- Department of Nutrition, Food Science and Physiology, University of Navarra, Pamplona, Spain
| | - Ana Cristina Villaro
- Department of Histology and Pathological Anatomy, University of Navarra, Pamplona, Spain
| | - María Pilar Lostao
- Department of Nutrition, Food Science and Physiology, University of Navarra, Pamplona, Spain.,Nutrition Research Centre, University of Navarra, Pamplona, Spain.,IdiSNA, Navarra Institute for Health Research, Pamplona, Spain
| |
Collapse
|
2
|
Serão NVL, Matika O, Kemp RA, Harding JCS, Bishop SC, Plastow GS, Dekkers JCM. Genetic analysis of reproductive traits and antibody response in a PRRS outbreak herd. J Anim Sci 2014; 92:2905-21. [PMID: 24879764 DOI: 10.2527/jas.2014-7821] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Porcine reproductive and respiratory syndrome (PRRS) is the most economically significant disease impacting pig production in North America, Europe, and Asia, causing reproductive losses such as increased rates of stillbirth and mummified piglets. The objective of this study was to explore the genetic basis of host response to the PRRS virus (PRRSV) in a commercial multiplier sow herd before and after a PRRS outbreak, using antibody response and reproductive traits. Reproductive data comprising number born alive (NBA), number alive at 24 h (NA24), number stillborn (NSB), number born mummified (NBM), proportion born dead (PBD), number born dead (NBD), number weaned (NW), and number of mortalities through weaning (MW) of 5,227 litters from 1,967 purebred Landrace sows were used along with a pedigree comprising 2,995 pigs. The PRRS outbreak date was estimated from rolling averages of farrowing traits and was used to split the data into a pre-PRRS phase and a PRRS phase. All 641 sows in the herd during the outbreak were blood sampled 46 d after the estimated outbreak date and were tested for anti-PRRSV IgG using ELISA (sample-to-positive [S/P] ratio). Genetic parameters of traits were estimated separately for the pre-PRRS and PRRS phase data sets. Sows were genotyped using the PorcineSNP60 BeadChip, and genome-wide association studies (GWAS) were performed using method Bayes B. Heritability estimates for reproductive traits ranged from 0.01 (NBM) to 0.12 (NSB) and from 0.01 (MW) to 0.12 (NBD) for the pre-PRRS and PRRS phases, respectively. S/P ratio had heritability (0.45) and strong genetic correlations with most traits, ranging from -0.72 (NBM) to 0.73 (NBA). In the pre-PRRS phase, regions associated with NSB and PBD explained 1.6% and 3% of the genetic variance, respectively. In the PRRS phase, regions associated with NBD, NSB, and S/P ratio explained 0.8%, 11%, and 50.6% of the genetic variance, respectively. For S/P ratio, 2 regions on SSC 7 (SSC7) separated by 100 Mb explained 40% of the genetic variation, including a region encompassing the major histocompatibility complex, which explained 25% of the genetic variance. These results indicate a significant genomic component associated with PRRSV antibody response and NSB in this data set. Also, the high heritability and genetic correlation estimates for S/P ratio during the PRRS phase suggest that S/P ratio could be used as an indicator of the impact of PRRS on reproductive traits.
Collapse
Affiliation(s)
- N V L Serão
- Department of Animal Science, Iowa State University, Ames 50011
| | - O Matika
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
| | - R A Kemp
- Genesus, Oakville, MB R0H 0Y0, Canada
| | - J C S Harding
- Department of Large Animal Clinical Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A1, Canada
| | - S C Bishop
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush, Midlothian EH25 9RG, UK
| | - G S Plastow
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB T6G 2R3, Canada
| | - J C M Dekkers
- Department of Animal Science, Iowa State University, Ames 50011
| |
Collapse
|
3
|
Kim E, Seok HH, Lee SY, Lee DR, Moon J, Yoon TK, Lee WS, Lee KA. Correlation between Expression of Glucose Transporters in Granulosa Cells and Oocyte Quality in Women with Polycystic Ovary Syndrome. Endocrinol Metab (Seoul) 2014; 29:40-7. [PMID: 24741453 PMCID: PMC3970285 DOI: 10.3803/enm.2014.29.1.40] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Accepted: 10/11/2013] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND The glucose transporters (GLUTs) exhibit different tissue-specific expression. This study aimed to investigate the types of GLUTs expressed in human granulosa cells (GCs) obtained from women with polycystic ovary syndrome (PCOS) and their relationship with insulin resistance (IR) and the outcomes of in vitro maturation (IVM) of immature oocytes. METHODS Expression of GLUTs was evaluated in GCs from women with PCOS with or without IR. Thirty-six women with PCOS undergoing an IVM program were included. Differential gene expression between the insulin sensitive (IS) and IR group was measured by reverse transcription polymerase chain reaction. RESULTS Expression of GLUTs 1, 3, 5, 8, and 13 was constitutive, whereas expression of GLUTs 2 and 7 was not observed in human GCs. The remaining GLUTs, 4, 6, 9, 10, 11, and 12, were differentially expressed among patients according to metabolic status, such as insulin sensitivity. A higher number of GCs from patients with IR (92%) expressed GLUT6 than GCs from IS PCOS patients (46.3%). Logistic regression showed that expression of GLUTs 9, 11, and 12 correlates with rates of IVM at 48 hours, fertilization, and implantation, respectively. CONCLUSION This is the first report describing the expression pattern of all 13 members of the GLUT family in human GCs. Results of the present study suggest that patients' insulin sensitivity regulates GLUT expression in GCs in PCOS patients, and this may control oocyte quality for IVM and subsequent processes such as fertilization and implantation in patients taking part in an in vitro fertilization program.
Collapse
Affiliation(s)
- Eunju Kim
- Department of Biomedical Science, CHA University, Seoul, Korea
| | - Hyun Ha Seok
- Fertility Center, CHA Gangnam Medical Center, CHA University, Seoul, Korea
| | - Su-Yeon Lee
- Department of Biomedical Science, CHA University, Seoul, Korea
| | - Dong Ryul Lee
- Department of Biomedical Science, CHA University, Seoul, Korea
- Fertility Center, CHA Gangnam Medical Center, CHA University, Seoul, Korea
| | - Jisook Moon
- Department of Applied Bioscience, CHA University, Seoul, Korea
| | - Tae Ki Yoon
- Fertility Center, CHA Gangnam Medical Center, CHA University, Seoul, Korea
| | - Woo Sik Lee
- Fertility Center, CHA Gangnam Medical Center, CHA University, Seoul, Korea
| | - Kyung-Ah Lee
- Department of Biomedical Science, CHA University, Seoul, Korea
- Fertility Center, CHA Gangnam Medical Center, CHA University, Seoul, Korea
| |
Collapse
|
4
|
Jung JH, Wang XD, Loeken MR. Mouse embryonic stem cells established in physiological-glucose media express the high KM Glut2 glucose transporter expressed by normal embryos. Stem Cells Transl Med 2013; 2:929-34. [PMID: 24167319 DOI: 10.5966/sctm.2013-0093] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Glut2 is one of the facilitative glucose transporters expressed by preimplantation and early postimplantation embryos. Glut2 is important for survival before embryonic day 10.5. The Glut2 KM (∼16 mmol/liter) is significantly higher than physiologic glucose concentrations (∼5.5 mmol/liter), suggesting that Glut2 normally performs some essential function other than glucose transport. Nevertheless, Glut2 efficiently transports glucose when extracellular glucose concentrations are above the Glut2 KM. Media containing 25 mmol/liter glucose are widely used to establish and propagate embryonic stem cells (ESCs). Glut2-mediated glucose uptake by embryos induces oxidative stress and can cause embryo cell death. Here we tested the hypothesis that low-glucose embryonic stem cells (LG-ESCs) isolated in physiological-glucose (5.5 mmol/liter) media express a functional Glut2 glucose transporter. LG-ESCs were compared with conventional D3 ESCs that had been cultured only in high-glucose media. LG-ESCs expressed Glut2 mRNA and protein at much higher levels than D3 ESCs, and 2-deoxyglucose transport by LG-ESCs, but not D3 ESCs, exhibited high Michaelis-Menten kinetics. Glucose at 25 mmol/liter induced oxidative stress in LG-ESCs and inhibited expression of Pax3, an embryo gene that is inhibited by hyperglycemia, in neuronal precursors derived from LG-ESCs. These effects were not observed in D3 ESCs. These findings demonstrate that ESCs isolated in physiological-glucose media retain a functional Glut2 transporter that is expressed by embryos. These cells are better suited to the study of metabolic regulation characteristic of the early embryo and may be advantageous for therapeutic applications.
Collapse
Affiliation(s)
- Jin Hyuk Jung
- Section on Islet Cell and Regenerative Biology, Joslin Diabetes Center, Department of Medicine, Harvard Medical School, Boston, Massachusetts, USA
| | | | | |
Collapse
|
5
|
Karim S, Adams DH, Lalor PF. Hepatic expression and cellular distribution of the glucose transporter family. World J Gastroenterol 2012; 18:6771-81. [PMID: 23239915 PMCID: PMC3520166 DOI: 10.3748/wjg.v18.i46.6771] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 09/10/2012] [Accepted: 09/19/2012] [Indexed: 02/06/2023] Open
Abstract
Glucose and other carbohydrates are transported into cells using members of a family of integral membrane glucose transporter (GLUT) molecules. To date 14 members of this family, also called the solute carrier 2A proteins have been identified which are divided on the basis of transport characteristics and sequence similarities into several families (Classes 1 to 3). The expression of these different receptor subtypes varies between different species, tissues and cellular subtypes and each has differential sensitivities to stimuli such as insulin. The liver is a contributor to metabolic carbohydrate homeostasis and is a major site for synthesis, storage and redistribution of carbohydrates. Situations in which the balance of glucose homeostasis is upset such as diabetes or the metabolic syndrome can lead metabolic disturbances that drive chronic organ damage and failure, confirming the importance of understanding the molecular regulation of hepatic glucose homeostasis. There is a considerable literature describing the expression and function of receptors that regulate glucose uptake and release by hepatocytes, the most import cells in glucose regulation and glycogen storage. However there is less appreciation of the roles of GLUTs expressed by non parenchymal cell types within the liver, all of which require carbohydrate to function. A better understanding of the detailed cellular distribution of GLUTs in human liver tissue may shed light on mechanisms underlying disease pathogenesis. This review summarises the available literature on hepatocellular expression of GLUTs in health and disease and highlights areas where further investigation is required.
Collapse
|
6
|
The facilitative glucose transporter GLUT12: what do we know and what would we like to know? J Physiol Biochem 2012; 69:325-33. [DOI: 10.1007/s13105-012-0213-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Accepted: 09/12/2012] [Indexed: 12/22/2022]
|
7
|
Dorniak P, Bazer FW, Wu G, Spencer TE. Conceptus-derived prostaglandins regulate endometrial function in sheep. Biol Reprod 2012; 87:9, 1-7. [PMID: 22517622 DOI: 10.1095/biolreprod.112.100487] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
In sheep, the trophectoderm of the elongating conceptus secretes interferon tau (IFNT) and prostaglandins (PGE2, PGF2alpha, PGI2). The PGs are derived from PG synthase 2 (PTGS2), and inhibition of PTGS2 in utero prevents conceptus elongation. IFNT increases expression of many genes in the endometrial epithelia that regulate conceptus elongation. This study tested the hypothesis that PGs secreted by the conceptus regulate endometrial functions that govern conceptus elongation. Cyclic ewes received intrauterine infusions of control vehicle or early pregnancy levels of IFNT, PGE2, PGF2alpha, or PGI2 from Days 10-14 postestrus. Expression levels of endometrial GRP, IGFBP1, and LGALS15, whose products stimulate trophectoderm cell migration and attachment, were increased by PGE2, PGI2, and IFNT. All PGs and IFNT increased expression of the HEXB protease gene, but only IFNT increased the CST6 protease inhibitor gene. Differential effects of PGs were observed for expression of the CTSL protease gene and its inhibitor, CST3. IFNT, PGF2alpha, and PGI2 increased ANGPTL3 expression, but only IFNT and PGE2 increased HIF1A expression, both of which regulate angiogenesis. For glucose transporters, IFNT and all PGs increased SLC2A1 expression, but only PGs increased SLC2A5 expression, whereas endometrial SLC2A12 and SLC5A1 expression levels were increased by IFNT, PGE2, and PGF2alpha. Infusions of all PGs and IFNT increased the amino acid transporter SLC1A5, but only IFNT increased SLC7A2 expression. In the uterine lumen, only IFNT increased glucose levels, and only PGE2 and PGF2alpha increased total amino acids. These results indicate that PGs and IFNT from the conceptus coordinately regulate endometrial functions important for growth and development of the conceptus during the peri-implantation period of pregnancy.
Collapse
Affiliation(s)
- Piotr Dorniak
- Center for Reproductive Biology, Department of Animal Sciences, Washington State University, Pullman, Washington, USA
| | | | | | | |
Collapse
|
8
|
Aerni-Flessner LB, Otu MC, Moley KH. The amino acids upstream of NH(2)-terminal dileucine motif play a role in regulating the intracellular sorting of the Class III transporters GLUT8 and GLUT12. Mol Membr Biol 2010; 28:30-41. [PMID: 21067453 DOI: 10.3109/09687688.2010.508196] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The transport of glucose across cell membranes is mediated by a family of facilitative glucose transporters (GLUTs). The class III glucose transporters GLUT8 and GLUT12 both contain a similar [DE]XXXL[LI] dileucine sorting signal in their amino terminus. This type of dileucine motif facilitates protein trafficking to various organelles or to the plasma membrane via interactions with adaptor protein (AP) complexes. The [DE]XXXL[LI] motif in GLUT8 is thought to direct it to late endosomal/lysosomal compartments via its interactions with AP1 and AP2. Unlike GLUT8, the [DE]XXXL[LI] motif does not direct GLUT12 to a lysosomal compartment. Rather, GLUT12 resides in the Golgi network and at the plasma membrane. In a previous study, we found that exchanging the XXX (TQP) residues in GLUT8 with the corresponding residues in GLUT12 (GPN) resulted in a dramatic missorting of GLUT8 to the cell surface. We postulated that the XXX amino acids upstream of the dileucine motif in GLUT8 influence the degree of interaction between the [DE]XXXL[LI] motif and adaptor proteins. To further explore its trafficking mechanisms, we created mutant constructs to identify the role that each of the individual XXX amino acids has for regulating the intracellular sorting of GLUT8. Here we find that the XXX amino acids, specifically the position of a proline -2 from the dileucine residues, influence the affinity of APs for GLUT8 and GLUT12.
Collapse
Affiliation(s)
- Lauren B Aerni-Flessner
- Departments of Obstetrics and Gynecology and Cell Biology and Physiology, Washington University School of Medicine, St Louis, MO 63110 USA
| | | | | |
Collapse
|
9
|
Purcell SH, Moley KH. Glucose transporters in gametes and preimplantation embryos. Trends Endocrinol Metab 2009; 20:483-9. [PMID: 19811929 PMCID: PMC6175277 DOI: 10.1016/j.tem.2009.06.006] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Revised: 06/17/2009] [Accepted: 06/18/2009] [Indexed: 10/20/2022]
Abstract
The oocyte, sperm and preimplantation embryo have unique metabolic needs that must be met to ensure successful pregnancy. The family of facilitative glucose transporters (GLUTs) plays a major role in providing metabolic substrates to these tissues. The variety of GLUTs expressed in these tissues allows for flexibility to adapt to a changing environment. Alterations in glucose transport and metabolism at the earliest stages of development can impact fetal development. Research into the mechanisms of normal glucose transport into cells is critical for improving outcomes in the increasingly common diabetic maternal environment. Here, we review the current understanding in the distribution and role of glucose transporters in gametes and preimplantation embryos under normal and diabetic conditions.
Collapse
Affiliation(s)
- Scott H Purcell
- Department of Obstetrics and Gynecology, Washington University in St. Louis, St. Louis, MO, USA
| | | |
Collapse
|
10
|
Schmidt S, Hommel A, Gawlik V, Augustin R, Junicke N, Florian S, Richter M, Walther DJ, Montag D, Joost HG, Schürmann A. Essential role of glucose transporter GLUT3 for post-implantation embryonic development. J Endocrinol 2009; 200:23-33. [PMID: 18948350 PMCID: PMC2632781 DOI: 10.1677/joe-08-0262] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Deletion of glucose transporter gene Slc2a3 (GLUT3) has previously been reported to result in embryonic lethality. Here, we define the exact time point of growth arrest and subsequent death of the embryo. Slc2a3(-/-) morulae and blastocysts developed normally, implanted in vivo, and formed egg-cylinder-stage embryos that appeared normal until day 6.0. At day 6.5, apoptosis was detected in the ectodermal cells of Slc2a3(-/-) embryos resulting in severe disorganization and growth retardation at day 7.5 and complete loss of embryos at day 12.5. GLUT3 was detected in placental cone, in the visceral ectoderm and in the mesoderm of 7.5-day-old wild-type embryos. Our data indicate that GLUT3 is essential for the development of early post-implanted embryos.
Collapse
Affiliation(s)
- S Schmidt
- Department of PharmacologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
| | - A Hommel
- Department of PharmacologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
| | - V Gawlik
- Department of PharmacologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
| | - R Augustin
- Department of PharmacologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
| | - N Junicke
- Department of PharmacologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
| | - S Florian
- Department of ToxicologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
| | - M Richter
- Department of PharmacologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
| | - D J Walther
- Department of Human Molecular GeneticsMax Planck Institute for Molecular GeneticsD-14195, BerlinGermany
| | - D Montag
- Research Group NeurogeneticsLeibniz-Institute for NeurobiologyD-39118, MagdeburgGermany
| | - H-G Joost
- Department of PharmacologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
| | - A Schürmann
- Department of PharmacologyGerman Institute of Human NutritionPotsdam-Rehbruecke, Arthur-Scheunert-Allee 114-116, D-14558, NuthetalGermany
- Correspondence should be addressed to A Schürmann ()
| |
Collapse
|
11
|
Flessner LB, Moley KH. Similar [DE]XXXL[LI] motifs differentially target GLUT8 and GLUT12 in Chinese hamster ovary cells. Traffic 2008; 10:324-33. [PMID: 19076329 DOI: 10.1111/j.1600-0854.2008.00866.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The transport of glucose across cell membranes is mediated by facilitative glucose transporters (GLUTs). The recently identified class III GLUT12 is predominantly expressed in insulin-sensitive tissues such as heart, fat and skeletal muscle. We examined the subcellular localization of GLUT12 in Chinese hamster ovary and human embryonic kidney 293 cells stably expressing murine GLUT12. We have previously shown that another class III GLUT8 contains a [DE]XXXL[LI] motif that directs it to late endosomal/lysosomal compartments. Despite also having this highly conserved motif in its amino terminus, GLUT12 does not colocalize with GLUT8. Rather, GLUT12 resides in the Golgi network and at the plasma membrane (PM). Furthermore, GLUT8 and GLUT12 exhibit dramatic differences in trafficking from the PM. Whereas GLUT8 is internalized following its expression at the cell surface, GLUT12 remains largely associated with the PM. To further explore the trafficking mechanisms, we created mutant constructs to explore the potential role of GLUT12's NH(2)-terminal dileucine motif in regulating its intracellular sorting. We show that both the GPN and the LL residues within the [DE]XXXL[LI] motif influence the cell surface expression of GLUT12 and conclude that the mechanisms governing the intracellular sorting of GLUT12 are distinct from those regulating the sorting of GLUT8.
Collapse
Affiliation(s)
- Lauren B Flessner
- Department of Obsetrics and Gynecology, Washington University School of Medicine, 660 South Euclid Ave, St Louis, MO 63110, USA
| | | |
Collapse
|
12
|
Ganguly A, McKnight RA, Raychaudhuri S, Shin BC, Ma Z, Moley K, Devaskar SU. Glucose transporter isoform-3 mutations cause early pregnancy loss and fetal growth restriction. Am J Physiol Endocrinol Metab 2007; 292:E1241-55. [PMID: 17213475 DOI: 10.1152/ajpendo.00344.2006] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucose transporter isoform-3 (GLUT3) is the trophoblastic facilitative glucose transporter. To investigate the role of this isoform in embryonic development, we created a novel GLUT3-null mouse and observed arrested early embryonic development and loss at neurulation stage when both alleles were mutated. This loss occurred despite the presence of other related isoforms, particularly GLUT1. In contrast, when a single allele was mutated, despite increased embryonic cell apoptosis, adaptive changes in the subcellular localization of GLUT3 and GLUT1 in the preimplantation embryo led to postimplantation survival. This survival was compromised by decreased GLUT3-mediated transplacental glucose transport, causing late-gestation fetal growth restriction. This yielded young male and female adults demonstrating catch-up growth, with normal basal glucose, insulin, insulin-like growth factor-I and IGF-binding protein-3 concentrations, fat and lean mass, and glucose and insulin tolerance. We conclude that GLUT3 mutations cause a gene dose-dependent early pregnancy loss or late-gestation fetal growth restriction despite the presence of embryonic and placental GLUT1 and a compensatory increase in system A amino acid placental transport. This critical life-sustaining functional role for GLUT3 in embryonic development provides the basis for investigating the existence of human GLUT3 mutations with similar consequences during early pregnancy.
Collapse
Affiliation(s)
- Amit Ganguly
- Division of Neonatology and Developmental Biology, Department of Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California 90095, USA.
| | | | | | | | | | | | | |
Collapse
|
13
|
Li R, Thorens B, Loeken MR. Expression of the gene encoding the high-Km glucose transporter 2 by the early postimplantation mouse embryo is essential for neural tube defects associated with diabetic embryopathy. Diabetologia 2007; 50:682-9. [PMID: 17235524 DOI: 10.1007/s00125-006-0579-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Accepted: 11/21/2006] [Indexed: 01/01/2023]
Abstract
AIMS/HYPOTHESIS Excess glucose transport to embryos during diabetic pregnancy causes congenital malformations. The early postimplantation embryo expresses the gene encoding the high-Km GLUT2 (also known as SLC2A2) glucose transporter. The hypothesis tested here is that high-Km glucose transport by GLUT2 causes malformations resulting from maternal hyperglycaemia during diabetic pregnancy. MATERIALS AND METHODS Glut2 mRNA was assayed by RT-PCR. The Km of embryo glucose transport was determined by measuring 0.5-20 mmol/l 2-deoxy[3H]glucose transport. To test whether the GLUT2 transporter is required for neural tube defects resulting from maternal hyperglycaemia, Glut2+/- mice were crossed and transient hyperglycaemia was induced by glucose injection on day 7.5 of pregnancy. Embryos were recovered on day 10.5, and the incidence of neural tube defects in wild-type, Glut2+/- and Glut2-/- embryos was scored. RESULTS Early postimplantation embryos expressed Glut2, and expression was unaffected by maternal diabetes. Moreover, glucose transport by these embryos showed Michaelis-Menten kinetics of 16.19 mmol/l, consistent with transport mediated by GLUT2. In pregnancies made hyperglycaemic on day 7.5, neural tube defects were significantly increased in wild-type embryos, but Glut2+/- embryos were partially protected from neural tube defects, and Glut2-/- embryos were completely protected from these defects. The frequency of occurrence of wild-type, Glut2+/- and Glut2-/- embryos suggests that the presence of Glut2 alleles confers a survival advantage in embryos before day 10.5. CONCLUSIONS/INTERPRETATIONS High-Km glucose transport by the GLUT2 glucose transporter during organogenesis is responsible for the embryopathic effects of maternal diabetes.
Collapse
Affiliation(s)
- R Li
- Developmental and Stem Cell Biology, Joslin Diabetes Center, 1 Joslin Place, Boston, MA 02215, USA
| | | | | |
Collapse
|
14
|
Seki Y, Berggren JR, Houmard JA, Charron MJ. Glucose Transporter Expression in Skeletal Muscle of Endurance-Trained Individuals. Med Sci Sports Exerc 2006; 38:1088-92. [PMID: 16775550 DOI: 10.1249/01.mss.0000222837.74015.f1] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
UNLABELLED Two recently identified glucose transporters, GLUT8 and GLUT12, are expressed in human skeletal muscle and may be involved in insulin-mediated sugar transport. PURPOSE The purpose of this study was to measure GLUT8 and GLUT12 mRNA levels in endurance-trained versus sedentary individuals in an effort to determine the effect of repeated days of contractile activity on gene expression. METHODS GLUT 4, 8, and 12 mRNA were measured in biopsies from the vastus lateralis using quantitative real-time PCR in endurance-trained (N=16, age=22.0+/-0.9 yr, VO(2 max) (L.min(-1))=4.13+/-0.25) and sedentary (N=15, age=21.3+/-0.8 yr, VO(2 max) (L.min(-1))=3.21+/-0.24) subjects. RESULTS GLUT12 mRNA was lower (40+/-14%, P<0.05) in the exercise-trained compared with the sedentary subjects. There was no difference between groups in GLUT8 mRNA content. mRNA of the insulin-sensitive glucose transporter (GLUT4) was 78+/-27% (P<0.05) higher in skeletal muscle from endurance-trained compared with sedentary individuals. CONCLUSION These findings suggest an isoform-specific effect on the mRNA of the glucose transporters in human skeletal muscle with repeated days of contractile activity.
Collapse
Affiliation(s)
- Yoshinori Seki
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | | | | |
Collapse
|
15
|
Riley JK, Moley KH. Glucose utilization and the PI3-K pathway: mechanisms for cell survival in preimplantation embryos. Reproduction 2006; 131:823-35. [PMID: 16672348 DOI: 10.1530/rep.1.00645] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The maintenance of optimal glucose utilization during the preimplantation period is critical for embryo survival. A decrease in glucose transport during preimplantation development has been linked to the early steps of programmed cell death in these embryos. Decreased glucose transport is not thought to be simply a consequence of cell death, rather it is thought to be a trigger that can initiate the apoptotic cascade. Extensive apoptosis during the preimplantation period may manifest later in pregnancy as a malformation – or miscarriage, if cell loss is excessive. Phosphatidylinositol 3-kinase (PI3-K) is a known regulator of a number of physiologic responses including cellular proliferation, growth, and survival as well as glucose metabolism. Studies performed in other cell systems have demonstrated that the PI3-K pathway plays a critical role in maintaining glucose transport and metabolism. This review will present the current evidence that suggests that PI3-K is vital for preimplantation embryo survival and development. In addition, data demonstrating that PI3-K activity is important for glucose metabolism during this early developmental period will be discussed.
Collapse
Affiliation(s)
- Joan K Riley
- Department of Obstetrics and Gynecology, Washington University School of Medicine, 4911 Barnes-Jewish Hospital Plaza, St Louis, Missouri 63110, USA
| | | |
Collapse
|