Reactive oxygen species downregulate glucose transport system in retinal endothelial cells

2011 ◽  
Vol 300 (4) ◽  
pp. C927-C936 ◽  
Author(s):  
Rosa Fernandes ◽  
Ken-ichi Hosoya ◽  
Paulo Pereira
Keyword(s):  
Oxidative Stress ◽  
Endothelial Cells ◽  
Plasma Membrane ◽  
Endothelial Cell ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Cell Damage ◽  
Proteasome Inhibition ◽  
Glucose Transporter 1 ◽  
Retinal Endothelial Cells

Retinal endothelial cells are believed to play an important role in the pathogenesis of diabetic retinopathy. In previous studies, we and others demonstrated that glucose transporter 1 (GLUT1) is downregulated in response to hyperglycemia. Increased oxidative stress is likely to be the event whereby hyperglycemia is transduced into endothelial cell damage. However, the effects of sustained oxidative stress on GLUT1 regulation are not clearly established. The objective of this study is to evaluate the effect of increased oxidative stress on glucose transport and on GLUT1 subcellular distribution in a retinal endothelial cell line and to elucidate the signaling pathways associated with such regulation. Conditionally immortalized rat retinal endothelial cells (TR-iBRB) were incubated with glucose oxidase, which increases the intracellular hydrogen peroxide levels, and GLUT1 regulation was investigated. The data showed that oxidative stress did not alter the total levels of GLUT1 protein, although the levels of mRNA were decreased, and there was a subcellular redistribution of GLUT1, decreasing its content at the plasma membrane. Consistently, the half-life of the protein at the plasma membrane markedly decreased under oxidative stress. The proteasome appears to be involved in GLUT1 regulation in response to oxidative stress, as revealed by an increase in stabilization of the protein present at the plasma membrane and normalization of glucose transport following proteasome inhibition. Indeed, levels of ubiquitinated GLUT1 increase as revealed by immunoprecipitation assays. Furthermore, data indicate that protein kinase B activation is involved in the stabilization of GLUT1 at the plasma membrane. Thus subcellular redistribution of GLUT1 under conditions of oxidative stress is likely to contribute to the disruption of glucose homeostasis in diabetes.

Erythrocyte Dematin Regulates Glucose Transport Via Akt Phosphorylation and 14-3-3zeta Association.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1990-1990
Author(s):  
Morvarid Mohseni ◽  
Anwar Khan ◽  
Athar H. Chishti
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Glucose Transport ◽  
Cell Biology ◽  
Glucose Transporter ◽  
Conflicts Of Interest ◽  
Adaptor Protein ◽  
Degradation Pathway ◽  
Actin Binding ◽  
Glucose Transporter 1

Abstract Abstract 1990 Poster Board I-1012 Erythrocyte dematin is a widely expressed actin-binding and bundling protein, and functions as a suppressor of RhoA signaling in fibroblasts (Mohseni and Chishti, Molecular Cell Biology 28: 4712-4718, 2008). Dematin is a substrate of multiple protein kinases, and its actin bundling activity is regulated by cAMP dependent protein kinase. Recently, we identified a novel interaction between dematin and glucose transporter-1 (GLUT1) that is critically important for erythrocyte shape and membrane mechanical properties (Khan et al., Journal of Biological Chemistry 283:14600-14609, 2008). Since homologues of dematin and GLUT1 exist in many non-erythroid cells, we proposed that a conserved mechanism might couple related sugar transporters, such as the insulin-responsive glucose transporter-4 (GLUT4), to the actin cytoskeleton via dematin. Immunocytochemistry established the presence of dematin in 3T3-L1 adipocytes, and a small pool of dematin and GLUT4-containing vesicles co-localized in 3T3-L1 cells under both basal and insulin-stimulated conditions. Plasma membrane sheet assays indicate that upon insulin stimulation, dematin translocates to the plasma membrane along with GLUT4, resulting in partial co-localization at the plasma membrane. Furthermore, dematin RNAi treated 3T3-L1 cells show reduced GLUT4 protein expression, suggesting that dematin may regulate a sub-population of GLUT4 via the lysosomal degradation pathway in adipocytes. Importantly, glucose transport was reduced by ∼28% in 3T3-L1 adipocytes depleted of dematin, and by ∼15% in the dematin headpiece knockout (HPKO) mouse primary adipocytes. Since a significant amount of dematin did not co-localize with GLUT4 in the cytosol and plasma membrane, biochemical interaction between dematin and GLUT4 could not be verified using immunoprecipitation and transfection assays. Although dematin does not bind directly to GLUT4 under these conditions, a possibility existed that this interaction may be transient and mediated through an adaptor protein. Interestingly, dematin contains seven 14-3-3 binding sites, and 14-3-3 adaptor has been shown to be functionally involved in GLUT4 trafficking. We demonstrate that phosphorylated dematin binds to 14-3-3 in 3T3-L1 adipocytes under both basal and insulin stimulated conditions. Mutagenesis studies identify serine-85 on dematin as the primary phospho-binding site for 14-3-3zeta. Furthermore, using pharmacological inhibitors, Akt is identified as the likely protein kinase that phosphorylates dematin to mediate the biochemical interactions between dematin and 14-3-3zeta. Together, our results identify erythrocyte dematin as a potential regulator of glucose transporter trafficking and degradation pathways in adipocytes with functional implications for glucose homeostasis, diabetes, and obesity. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Hypoxia induces the translocation of glucose transporter 1 to the plasma membrane in vascular endothelial cells

2020 ◽  
Vol 70 (1) ◽  
Author(s):  
Abdullah Al Mamun ◽  
Hisaki Hayashi ◽  
Aya Yamamura ◽  
Md Junayed Nayeem ◽  
Motohiko Sato
Keyword(s):  
Endothelial Cells ◽  
Plasma Membrane ◽  
Cell Surface ◽  
Glucose Uptake ◽  
Katp Channel ◽  
Glucose Transporter ◽  
Umbilical Vein ◽  
Cell Surface Expression ◽  
Glucose Transporter 1 ◽  
Intracellular Atp

Abstract Glucose uptake and adenosine triphosphate (ATP) generation are important for the survival and growth of endothelial cells. An increase of glucose uptake under hypoxia was previously shown to be associated with the increased expression of glucose transporters (GLUTs). However, the regulation of GLUT trafficking to the cell surface has not been examined in detail. Here, we report the characterization of GLUT1 translocation to the plasma membrane during hypoxia in endothelial cells. Human umbilical vein endothelial cells (HUVECs) were exposed to hypoxia (1% O2) for 12 h, which significantly induced GLUT1 expression and translocation to the plasma membrane. GLUT1 translocation was associated with a decrease of intracellular ATP by hypoxia. Decreasing ATP levels with antimycin-A and 2-deoxyglucose induced GLUT1 translocation under normoxia. The induction of hypoxia-inducible factor-1α under normoxia did not influence the cell surface expression of GLUT1 or cellular ATP concentration. Interestingly, the translocation of GLUT1 induced by hypoxia was inhibited by the ATP-sensitive potassium (KATP) channel inhibitor glibenclamide, while the mitochondrial KATP channel inhibitor 5-HD did not influence GLUT1 translocation during hypoxia. These observations indicate that a decrease of intracellular ATP triggers GLUT1 translocation to the plasma membrane and is mediated by KATP channels, which would contribute to glucose uptake in HUVECs during hypoxia.

scholarly journals Regulation of GLUT1-mediated glucose uptake by PKCλ–PKCβII interactions in 3T3-L1 adipocytes

2004 ◽  
Vol 384 (2) ◽  
pp. 349-355 ◽  
Author(s):  
Remko R. BOSCH ◽  
Merlijn BAZUINE ◽  
Paul N. SPAN ◽  
Peter H. G. M. WILLEMS ◽  
André J. OLTHAAR ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Protein Kinase ◽  
Glucose Uptake ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Mitogen Activated Protein Kinase ◽  
Glucose Transporter 1 ◽  
Protein Levels ◽  
Mitogen Activated Protein ◽  
Pkc Protein Kinase C

Members of the PKC (protein kinase C) superfamily play key regulatory roles in glucose transport. How the different PKC isotypes are involved in the regulation of glucose transport is still poorly defined. PMA is a potent activator of conventional and novel PKCs and PMA increases the rate of glucose uptake in many different cell systems. In the present study, we show that PMA treatment increases glucose uptake in 3T3-L1 adipocytes by two mechanisms: a mitogen-activated protein kinase kinase-dependent increase in GLUT1 (glucose transporter 1) expression levels and a PKCλ-dependent translocation of GLUT1 towards the plasma membrane. Intriguingly, PKCλ co-immunoprecipitated with PKCβII and did not with PKCβI. Previously, we have described that down-regulation of PKCβII protein levels or inhibiting PKCβII by means of the myristoylated PKCβC2–4 peptide inhibitor induced GLUT1 translocation towards the plasma membrane in 3T3-L1 adipocytes. Combined with the present findings, these results suggest that the liberation of PKCλ from PKCβII is an important factor in the regulation of GLUT1 distribution in 3T3-L1 adipocytes.

scholarly journals High stretch induces endothelial dysfunction accompanied by oxidative stress and actin remodeling in human saphenous vein endothelial cells

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Girão-Silva ◽  
M. H. Fonseca-Alaniz ◽  
J. C. Ribeiro-Silva ◽  
J. Lee ◽  
N. P. Patil ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Endothelial Cells ◽  
Endothelial Cell ◽  
Endothelial Dysfunction ◽  
Saphenous Vein ◽  
Saphenous Vein Graft ◽  
Artery Bypass ◽  
Bypass Graft ◽  
Human Saphenous Vein ◽  
Actin Remodeling

AbstractThe rate of the remodeling of the arterialized saphenous vein conduit limits the outcomes of coronary artery bypass graft surgery (CABG), which may be influenced by endothelial dysfunction. We tested the hypothesis that high stretch (HS) induces human saphenous vein endothelial cell (hSVEC) dysfunction and examined candidate underlying mechanisms. Our results showed that in vitro HS reduces NO bioavailability, increases inflammatory adhesion molecule expression (E-selectin and VCAM1) and THP-1 cell adhesion. HS decreases F-actin in hSVECs, but not in human arterial endothelial cells, and is accompanied by G-actin and cofilin’s nuclear shuttling and increased reactive oxidative species (ROS). Pre-treatment with the broad-acting antioxidant N-acetylcysteine (NAC) supported this observation and diminished stretch-induced actin remodeling and inflammatory adhesive molecule expression. Altogether, we provide evidence that increased oxidative stress and actin cytoskeleton remodeling play a role in HS-induced saphenous vein endothelial cell dysfunction, which may contribute to predisposing saphenous vein graft to failure.

Abstract 112: A Pathological Role of Endothelial p53 in the Regulation of Endothelial Function and Glucose Metabolism

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Masataka YOKOYAMA ◽  
Yoshio KOBAYASHI ◽  
Tohru MINAMINO
Keyword(s):  
Skeletal Muscle ◽  
Endothelial Cell ◽  
Glucose Metabolism ◽  
Endothelial Function ◽  
Mitochondrial Biogenesis ◽  
Glucose Transporter ◽  
Diabetic Patients ◽  
Glucose Transporter 1 ◽  
P53 Activation

Cellular senescence is a state of irreversible growth arrest induced by various stresses such as oncogenic stimuli. This response is controlled by negative regulators of the cell cycle like the p53 tumor suppressor protein. Accumulating evidence has suggested a role of p53 activation in various age-associated conditions including atherosclerosis, heart failure and diabetes. Here we show that endothelial p53 activation plays a pathological role in the regulation of endothelial function and glucose metabolism under diabetic conditions. Endothelial expression of p53 was markedly up-regulated in a streptozotocin-induced diabetes model. Endothelial function such as acetylcholine-dependent vasodilatation was markedly impaired in this model. Although hyperglycemia was not altered, impairment of endothelial function was significantly improved in mice with endothelial cell-specific p53 deficiency. In same way, p53 was markedly activated in ischemic vessels, and endothelial p53 deficiency enhanced ischemia-induced angiogenesis. Mechanistically, endothelial p53 up-regulated the expression of PTEN that negatively regulated the Akt-eNOS pathway, and therefore disruption of p53 improved endothelial dysfunction. We also found that endothelial p53 was markedly activated, and the Akt-eNOS pathway was attenuated in a diet-induced obesity model. Disruption of endothelial p53 activation improved dietary inactivation of eNOS that up-regulated the expression of PGC-1α in skeletal muscle, thereby increasing mitochondrial biogenesis and oxygen consumption. Inhibition of endothelial p53 also improved dietary impairment of glucose transport into skeletal muscle by up-regulating endothelial expression of glucose transporter 1. Consequently, mice with endothelial cell-specific p53 deficiency fed a high-calorie diet showed improvement of insulin sensitivity and less fat accumulation compared with control littermates. These results indicate that endothelial p53 negatively regulates endothelium-dependent vasodilatation, ischemia-induced angiogenesis, and mitochondrial biogenesis by inhibiting the Akt-eNOS pathway and suggest that inhibition of endothelial p53 could be a novel therapeutic target in diabetic patients.

scholarly journals The The Role Of Von Willenbrand Factors As The Early Detection Of Endotel Cell Damage In Youth Ages With Obesity In The Usu Medan Campus Environment

2021 ◽  
Vol 6 (1) ◽  
pp. 179-181
Author(s):  
Rusdiana ◽  
Muhammad Syahputra ◽  
Sry Suryani
Keyword(s):  
Oxidative Stress ◽  
Endothelial Cells ◽  
Vascular System ◽  
Cell Damage ◽  
Single Layer ◽  
Control Group ◽  
Research Subjects ◽  
Cross Sectional ◽  
Significant Difference ◽  
Obese Subjects

Preliminary : Endothelial cells are a single layer that lines the entire vascular system. Endothelial dysfunction can be triggered by several main things, namely physical stress, oxidative stress and irritant substances. Obesity triggers an inflammatory process and metabolic disorders that will lead to increased oxidative stress. Long-term oxidative stress will cause damage to cells and tissues and trigger degenerative diseases. Damage to endothelial cells is expected to be detected by examining Von Willenbrand levels so that it can prevent complications of vascular disorders early. Method: This research is descriptive with cross sectional design. Carried out from March to October 2018 on the USU Campus. The first examination was done to measure body weight and height to determine body mass index, then performed lipid profile and blood sugar levels (KGD) in the sample, then examined von Willenbrand factor levels carried out in the integrated laboratory of USU FK using the method ELISA in both the sample group and the control group. The research subjects were adolescents aged 17-25 years with BMI> 25 kg / m2Data analysis was carried out using the T-Test statistical program, comparing two groups. Result: Of the 40 obese subjects found Von Wilenbrand level values ​​The lowest factor was 1.78 IU / ml and the highest was 35.60 IU / ml. Whereas in 40 non-obese subjects Von Wilenbrand grade values ​​were the lowest factor of 2.01 IU / ml and the highest was 45.10 IU / ml. This difference was not statistically significant (p = 0.661).Conclusion: There was no significant difference between the levels of Von Wilenbrand Factors in obese subjects with non-obese subjectsKey Words: Obesity, endothelial cells, Von Wilenbrand Factors

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