scholarly journals Tsg101 Is Involved in the Sorting and Re-Distribution of Glucose Transporter-4 to the Sarcolemma Membrane of Cardiac Myocytes

Cells ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1936
Author(s):  
Kobina Essandoh ◽  
Shan Deng ◽  
Xiaohong Wang ◽  
Yutian Li ◽  
Qianqian Li ◽  
...  
Keyword(s):  
Cardiac Myocytes ◽  
Glucose Transporter ◽  
Ischemia Reperfusion ◽  
Susceptibility Gene ◽  
Cardiac Cells ◽  
Acid Oxidation ◽  
Glucose Transporter 4 ◽  
Loss Of Function ◽  
Glut 4 ◽  
Insulin Dependent

Cardiac cells can adapt to pathological stress-induced energy crisis by shifting from fatty acid oxidation to glycolysis. However, the use of glucose-insulin-potassium (GIK) solution in patients undergoing cardiac surgery does not alleviate ischemia/reperfusion (I/R)-induced energy shortage. This indicates that insulin-mediated translocation of glucose transporter-4 (Glut-4) is impaired in ischemic hearts. Indeed, cardiac myocytes contain two intracellular populations of Glut-4: an insulin-dependent non-endosomal pool (also referred to as Glut-4 storage vesicles, GSVs) and an insulin-independent endosomal pool. Tumor susceptibility gene 101 (Tsg101) has been implicated in the endosomal recycling of membrane proteins. In this study, we aimed to examine whether Tsg101 regulated the sorting and re-distribution of Glut-4 to the sarcolemma membrane of cardiomyocytes under basal and ischemic conditions, using gain- and loss-of-function approaches. Forced overexpression of Tsg101 in mouse hearts and isolated cardiomyocytes could promote Glut-4 re-distribution to the sarcolemma, leading to enhanced glucose entry and adenosine triphosphate (ATP) generation in I/R hearts which in turn, attenuation of I/R-induced cardiac dysfunction. Conversely, knockdown of Tsg101 in cardiac myocytes exhibited opposite effects. Mechanistically, we identified that Tsg101 could interact and co-localize with Glut-4 in the sarcolemma membrane of cardiomyocytes. Our findings define Tsg101 as a novel regulator of cardiac Glut-4 trafficking, which may provide a new therapeutic strategy for the treatment of ischemic heart disease.

scholarly journals Molecular regulation of GLUT-4 targeting in 3T3-L1 adipocytes.

1995 ◽  
Vol 130 (5) ◽  
pp. 1081-1091 ◽  
Author(s):  
B J Marsh ◽  
R A Alm ◽  
S R McIntosh ◽  
D E James
Keyword(s):  
Cell Surface ◽  
Glucose Transporter ◽  
Subcellular Fractionation ◽  
Molecular Regulation ◽  
Surface Distribution ◽  
Amino Terminal ◽  
Glut 4 ◽  
Dileucine Motif ◽  
A Cell ◽  
Insulin Dependent

Insulin stimulates glucose transport in muscle and adipose tissue by triggering the movement of the glucose transporter GLUT-4 from an intracellular compartment to the cell surface. Fundamental to this process is the intracellular sequestration of GLUT-4 in nonstimulated cells. Two distinct targeting motifs in the amino and carboxy termini of GLUT-4 have been previously identified by expressing chimeras comprised of portions of GLUT-4 and GLUT-1, a transporter isoform that is constitutively targeted to the cell surface, in heterologous cells. These motifs-FQQI in the NH2 terminus and LL in the COOH terminus-resemble endocytic signals that have been described in other proteins. In the present study we have investigated the roles of these motifs in GLUT-4 targeting in insulin-sensitive cells. Epitope-tagged GLUT-4 constructs engineered to differentiate between endogenous and transfected GLUT-4 were stably expressed in 3T3-L1 adipocytes. Targeting was assessed in cells incubated in the presence or absence of insulin by subcellular fractionation. The targeting of epitope-tagged GLUT-4 was indistinguishable from endogenous GLUT-4. Mutation of the FQQI motif (F5 to A5) caused GLUT-4 to constitutively accumulate at the cell surface regardless of expression level. Mutation of the dileucine motif (L489L490 to A489A490) caused an increase in cell surface distribution only at higher levels of expression, but the overall cells surface distribution of this mutant was less than that of the amino-terminal mutants. Both NH2- and COOH-terminal mutants retained insulin-dependent movement from an intracellular to a cell surface locale, suggesting that neither of these motifs is involved in the insulin-dependent redistribution of GLUT-4. We conclude that the phenylalanine-based NH2-terminal and the dileucine-based COOH-terminal motifs play important and distinct roles in GLUT-4 targeting in 3T3-L1 adipocytes.

scholarly journals Paracrine effects of hypoxic fibroblast-derived factors on the MPT-ROS threshold and viability of adult rat cardiac myocytes

2008 ◽  
Vol 294 (6) ◽  
pp. H2653-H2658 ◽  
Author(s):  
K. Shivakumar ◽  
S. J. Sollott ◽  
M. Sangeetha ◽  
S. Sapna ◽  
B. Ziman ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Conditioned Medium ◽  
Cardiac Myocytes ◽  
Cytokine Production ◽  
Mitochondrial Permeability Transition ◽  
Cardiac Fibroblasts ◽  
Ischemia Reperfusion ◽  
Oxidant Stress ◽  
Cardiac Cells ◽  
Tnf Α

Cardiac fibroblasts contribute to multiple aspects of myocardial function and pathophysiology. The pathogenetic relevance of cytokine production by these cells under hypoxia, however, remains unexplored. With the use of an in vitro cell culture model, this study evaluated cytokine production by hypoxic cardiac fibroblasts and examined two distinct effects of hypoxic fibroblast-conditioned medium (HFCM) on cardiac myocytes and fibroblasts. Hypoxia caused a marked increase in the production of tumor necrosis factor (TNF)-α by cardiac fibroblasts. HFCM significantly enhanced the susceptibility of cardiac myocytes to reactive oxygen species (ROS)-induced mitochondrial permeability transition (MPT), determined by high-precision confocal line-scan imaging following controlled, photoexcitation-induced ROS production within individual mitochondria. Furthermore, exposure of cardiac myocytes to HFCM for 5 h led to loss of viability, as evidenced by change in morphology and annexin staining. HFCM also decreased DNA synthesis in cardiac fibroblasts. Normoxic fibroblast-conditioned medium spiked with TNF-α at 200 pg/ml, a concentration comparable to that in HFCM, promoted loss of myocyte viability and decreased DNA synthesis in cardiac fibroblasts. These effects of HFCM are similar to the reported effects of hypoxia per se on these cell types, showing that hypoxic fibroblast-derived factors may amplify the distinct effects of hypoxia on cardiac cells. Importantly, because both hypoxia and oxidant stress prevail in a setting of ischemia and reperfusion, the effects of soluble factors from hypoxic fibroblasts on the MPT-ROS threshold and viability of myocytes may represent a novel paracrine mechanism that could exacerbate ischemia-reperfusion injury to cardiomyocytes.

scholarly journals Insulin-induced Recruitment of Glucose Transporter 4 (GLUT4) and GLUT1 in Isolated Rat Cardiac Myocytes

1997 ◽  
Vol 272 (11) ◽  
pp. 7085-7092 ◽  
Author(s):  
Yvan Fischer ◽  
Julia Thomas ◽  
Lidia Sevilla ◽  
Purificación Muñoz ◽  
Christoph Becker ◽  
...  
Keyword(s):  
Cardiac Myocytes ◽  
Glucose Transporter ◽  
Glucose Transporter 4 ◽  
Rat Cardiac Myocytes ◽  
Isolated Rat

scholarly journals Caveolin-1 Loss of Function Accelerates Glucose Transporter 4 and Insulin Receptor Degradation in 3T3-L1 Adipocytes

Endocrinology ◽  
2009 ◽  
Vol 150 (8) ◽  
pp. 3493-3502 ◽  
Author(s):  
Elena González-Muñoz ◽  
Carmen López-Iglesias ◽  
Maria Calvo ◽  
Manuel Palacín ◽  
Antonio Zorzano ◽  
...  
Keyword(s):  
Insulin Receptor ◽  
Cell Lines ◽  
Glucose Transporter ◽  
Lentiviral Vectors ◽  
Receptor Activation ◽  
Receptor Protein ◽  
Membrane Microdomains ◽  
Glucose Transporter 4 ◽  
Loss Of Function ◽  
Caveolin 1

Caveolae are a specialized type of lipid rafts that are stabilized by oligomers of caveolin protein. Caveolae are particularly enriched in adipocytes. Here we analyzed the effects of caveolin-1 knockdown and caveolae ablation on adipocyte function. To this end, we obtained several multiclonal mouse 3T3-L1 cell lines with a reduced expression of caveolin-1 (95% reduction) by a small interfering RNA approach using lentiviral vectors. Control cell lines were obtained by lentiviral infection with lentiviral vectors encoding appropriate scrambled RNAs. Caveolin-1 knockdown adipocytes showed a drastic reduction in the number of caveolae (95% decrease) and cholera toxin labeling was reorganized in dynamic plasma membrane microdomains. Caveolin-1 depletion caused a specific decrease in glucose transporter 4 (GLUT4) and insulin receptor protein levels. This reduction was not the result of a generalized defect in adipocyte differentiation or altered gene expression but was explained by faster degradation of these proteins. Caveolin-1 knockdown adipocytes showed reductions in insulin-stimulated glucose transport, insulin-triggered GLUT4 recruitment to the cell surface, and insulin receptor activation. In all, our data indicate that caveolin-1 loss of function reduces maximal insulin response through lowered stability and diminished expression of insulin receptors and GLUT4. We propose that caveolin-1/caveolae control insulin action in adipose cells.

scholarly journals Role of Caveolin-3 and Glucose Transporter-4 in Isoflurane-induced Delayed Cardiac Protection

2010 ◽  
Vol 112 (5) ◽  
pp. 1136-1145 ◽  
Author(s):  
Yasuo M. Tsutsumi ◽  
Yoshitaka Kawaraguchi ◽  
Yousuke T. Horikawa ◽  
Ingrid R. Niesman ◽  
Michael W. Kidd ◽  
...  
Keyword(s):  
Infarct Size ◽  
Knockout Mice ◽  
Glucose Transporter ◽  
Ischemia Reperfusion Injury ◽  
Ischemia Reperfusion ◽  
Glucose Transporter 4 ◽  
Wild Type ◽  
Cardiac Protection ◽  
Caveolin 1 ◽  
Discontinuous Sucrose Gradient

Background Caveolae are small, flask-like invaginations of the plasma membrane. Caveolins are structural proteins found in caveolae that have scaffolding properties to allow organization of signaling. The authors tested the hypothesis that delayed cardiac protection induced by volatile anesthetics is caveolae or caveolin dependent. Methods An in vivo mouse model of ischemia-reperfusion injury with delayed anesthetic preconditioning (APC) was tested in wild-type, caveolin-1 knockout, and caveolin-3 knockout mice. Mice were exposed to 30 min of oxygen or isoflurane and allowed to recover for 24 h. After 24 h recovery, mice underwent 30-min coronary artery occlusion followed by 2 h of reperfusion at which time infarct size was determined. Biochemical assays were also performed in excised hearts. Results Infarct size as a percent of the area at risk was reduced by isoflurane in wild-type (24.0 +/- 8.8% vs. 45.1 +/- 10.1%) and caveolin-1 knockout mice (27.2 +/- 12.5%). Caveolin-3 knockout mice did not show delayed APC (41.5 +/- 5.0%). Microscopically distinct caveolae were observed in wild-type and caveolin-1 knockout mice but not in caveolin-3 knockout mice. Delayed APC increased the amount of caveolin-3 protein but not caveolin-1 protein in discontinuous sucrose-gradient buoyant fractions. In addition, glucose transporter-4 was increased in buoyant fractions, and caveolin-3/glucose transporter-4 colocalization was observed in wild-type and caveolin-1 knockout mice after APC. Conclusions These results show that delayed APC involves translocation of caveolin-3 and glucose transporter-4 to caveolae, resulting in delayed protection in the myocardium.

Glucose Transporter 4 (GLUT 4) Is Highly Expressed in Mitochondria-rich Oxyphil Cells

1998 ◽  
Vol 6 (4) ◽  
pp. 224-227 ◽  
Author(s):  
J. M??ller-H??cker ◽  
A. Sch??fer ◽  
T. Strowitzki
Keyword(s):  
Glucose Transporter ◽  
Glucose Transporter 4 ◽  
Glut 4

scholarly journals Adipocytes Exhibit Abnormal Subcellular Distribution and Translocation of Vesicles Containing Glucose Transporter 4 and Insulin-Regulated Aminopeptidase in Type 2 Diabetes Mellitus: Implications Regarding Defects in Vesicle Trafficking

2001 ◽  
Vol 86 (11) ◽  
pp. 5450-5456 ◽  
Author(s):  
Lidia Maianu ◽  
Susanna R. Keller ◽  
W. Timothy Garvey
Keyword(s):  
Insulin Resistance ◽  
Type 2 Diabetes ◽  
Body Mass Index ◽  
Body Mass ◽  
Glucose Transporter ◽  
Diabetic Patients ◽  
Low Density ◽  
Glucose Transporter 4 ◽  
Glut 4

Insulin resistance in type 2 diabetes is due to impaired stimulation of the glucose transport system in muscle and fat. Different defects are operative in these two target tissues because glucose transporter 4 (GLUT 4) expression is normal in muscle but markedly reduced in fat. In muscle, GLUT 4 is redistributed to a dense membrane compartment, and insulin-mediated translocation to plasma membrane (PM) is impaired. Whether similar trafficking defects are operative in human fat is unknown. Therefore, we studied subcellular localization of GLUT4 and insulin-regulated aminopeptidase (IRAP; also referred to as vp165 or gp160), which is a constituent of GLUT4 vesicles and also translocates to PM in response to insulin. Subcutaneous fat was obtained from eight normoglycemic control subjects (body mass index, 29 ± 2 kg/m2) and eight type 2 diabetic patients (body mass index, 30 ± 1 kg/m2; fasting glucose, 14 ± 1 mm). In adipocytes isolated from diabetics, the basal 3-O-methylglucose transport rate was decreased by 50% compared with controls (7.1 ± 2.9 vs. 14.1 ± 3.7 mmol/mm2 surface area/min), and there was no increase in response to maximal insulin (7.9 ± 2.7 vs. 44.5 ± 9.2 in controls). In membrane subfractions from controls, insulin led to a marked increase of IRAP in the PM from 0.103 ± 0.04 to 1.00± 0.33 relative units/mg protein, concomitant with an 18% decrease in low-density microsomes and no change in high-density microsomes (HDM). In type 2 diabetes, IRAP overall expression in adipocytes was similar to that in controls; however, two abnormalities were observed. First, in basal cells, IRAP was redistributed away from low-density microsomes, and more IRAP was recovered in HDM (1.2-fold) and PM (4.4-fold) from diabetics compared with controls. Second, IRAP recruitment to PM by maximal insulin was markedly impaired. GLUT4 was depleted in all membrane subfractions (43–67%) in diabetes, and there was no increase in PM GLUT4 in response to insulin. Type 2 diabetes did not affect the fractionation of marker enzymes. We conclude that in human adipocytes: 1) IRAP is expressed and translocates to PM in response to insulin; 2) GLUT4 depletion involves all membrane subfractions in type 2 diabetes, although cellular levels of IRAP are normal; and 3) in type 2 diabetes, IRAP accumulates in membrane vesicles cofractionating with HDM and PM under basal conditions, and insulin-mediated recruitment to PM is impaired. Therefore, in type 2 diabetes, adipocytes express defects in trafficking of GLUT4/IRAP-containing vesicles similar to those causing insulin resistance in skeletal muscle.

scholarly journals Insulin responsiveness of glucose transporter 4 in 3T3-L1 cells depends on the presence of sortilin

2013 ◽  
Vol 24 (19) ◽  
pp. 3115-3122 ◽  
Author(s):  
Guanrong Huang ◽  
Dana Buckler-Pena ◽  
Tessa Nauta ◽  
Maneet Singh ◽  
Agnes Asmar ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Cell Sorting ◽  
Glucose Transporter ◽  
Glucose Transporter 4 ◽  
Insulin Stimulation ◽  
Cell Surface Biotinylation ◽  
Undifferentiated Cells ◽  
Insulin Dependent ◽  
Low Levels ◽  
Insulin Responsiveness

Insulin-dependent translocation of glucose transporter 4 (Glut4) to the plasma membrane of fat and skeletal muscle cells plays the key role in postprandial clearance of blood glucose. Glut4 represents the major cell-specific component of the insulin-responsive vesicles (IRVs). It is not clear, however, whether the presence of Glut4 in the IRVs is essential for their ability to respond to insulin stimulation. We prepared two lines of 3T3-L1 cells with low and high expression of myc7-Glut4 and studied its translocation to the plasma membrane upon insulin stimulation, using fluorescence-assisted cell sorting and cell surface biotinylation. In undifferentiated 3T3-L1 preadipocytes, translocation of myc7-Glut4 was low regardless of its expression levels. Coexpression of sortilin increased targeting of myc7-Glut4 to the IRVs, and its insulin responsiveness rose to the maximal levels observed in fully differentiated adipocytes. Sortilin ectopically expressed in undifferentiated cells was translocated to the plasma membrane regardless of the presence or absence of myc7-Glut4. AS160/TBC1D4 is expressed at low levels in preadipocytes but is induced in differentiation and provides an additional mechanism for the intracellular retention and insulin-stimulated release of Glut4.

scholarly journals Golden sea cucumber extract revives glucose transporter-4 and interleukin-6 protein level in diabetic mouse muscle

2019 ◽  
Vol 12 (5) ◽  
pp. 684-688
Author(s):  
Bambang Purwanto ◽  
Sundari Indah Wiyasihati ◽  
Putri Ayu Masyitha ◽  
Kristanti Wanito Wigati ◽  
Irfiansyah Irwadi
Keyword(s):  
Free Radical ◽  
Interleukin 6 ◽  
Protein Level ◽  
Sea Cucumber ◽  
Muscle Wasting ◽  
Glucose Transporter ◽  
Diabetic Mouse ◽  
Glucose Transporter 4 ◽  
Mouse Muscle ◽  
Glut 4

Background: Streptozotocin (STZ)-induced free radical oxidant activity resulted in muscle wasting due to protein carbonyl (PC), glucose transporter-4 (Glut-4), and interleukin-6 (IL-6) protein alteration. Antioxidant ingredient in the golden sea cucumber extract was found in promising level to inhibit free radical activity. Aim: This study was aimed to investigate the effect of golden sea cucumber extract on PC, IL-6, and Glut-4 level of STZ-induced diabetes mouse. Materials and Methods: This study was performed using mice, which were grouped into non-diabetes, diabetes, and diabetes-treated extract groups. The golden sea cucumber was extracted using 70% ethanol, which was administered by oral gavage twice a day for 5 consecutive days. Results: The extract reduced PC level and improved muscle Glut-4 and IL-6 protein level of diabetic mouse. Conclusion: The extract of golden sea cucumber revived muscle Glut-4 and IL-6 protein level in protection against muscle wasting.

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