scholarly journals Glucose metabolism down-regulates the uptake of 6-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (6-NBDG) mediated by glucose transporter 1 isoform (GLUT1): theory and simulations using the symmetric four-state carrier model

2013 ◽  
Vol 125 (2) ◽  
pp. 236-246 ◽  
Author(s):  
Mauro DiNuzzo ◽  
Federico Giove ◽  
Bruno Maraviglia ◽  
Silvia Mangia
2012 ◽  
Vol 24 (2) ◽  
pp. 344 ◽  
Author(s):  
M. Garcia-Herreros ◽  
I. M. Aparicio ◽  
D. Rath ◽  
T. Fair ◽  
P. Lonergan

Previous studies have shown that developmental kinetic rates following IVF are lower in female than in male blastocysts and that this may be related to differences in glucose metabolism. In addition, an inhibition of phosphatidylinositol 3-kinase (PI3-K) inhibits glucose uptake in murine blastocysts. Therefore, the aim of this study was to identify and compare the expression of proteins involved in glucose metabolism (hexokinase-I, HK-I; phosphofructokinase-1, PFK-1; pyruvate kinase1/2, PK1/2; glyceraldehyde-3-phosphate dehydrogenase, GAPDH; glucose transporter-1, GLUT-1; and glycogen synthase kinase-3, GSK-3) in male and female bovine blastocysts to determine whether PI3-K has a role in the regulation of the expression of these proteins. Hexokinase-I, PFK-1, PK1/2, GAPDH and GLUT-1 were present in bovine embryos. Protein expression of these proteins and GSK-3 was significantly higher in male compared with female blastocysts. Inhibition of PI3-K with LY294002 significantly decreased the expression of HK-I, PFK-1, GAPDH, GSK-3 A/B and GLUT-1. Results showed that the expression of glycolytic proteins HK-I, PFK-1, GAPDH and PK1/2, and the transporters GLUT-1 and GSK-3 is regulated by PI3-K in bovine blastocysts. Moreover, the differential protein expression observed between male and female blastocysts might explain the faster developmental kinetics seen in males, as the expression of main proteins involved in glycolysis and glycogenogenesis was significantly higher in male than female bovine embryos and also could explain the sensitivity of male embryos to a high concentration of glucose, as a positive correlation between GLUT-1 expression and glucose uptake in embryos has been demonstrated.


2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Masataka YOKOYAMA ◽  
Yoshio KOBAYASHI ◽  
Tohru MINAMINO

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.


2019 ◽  
Vol 10 (12) ◽  
Author(s):  
Kuan Li ◽  
Minmin Li ◽  
Wenli Li ◽  
Hongzhi Yu ◽  
Xin Sun ◽  
...  

AbstractEfficient repair of injured epithelium by airway progenitor cells could prevent acute inflammation from progressing into chronic phase in lung. Here, we used small molecules, genetic loss-of-function, organoid cultures, and in vivo lung-injury models to show that autophagy is essential for maintaining the pool of airway stem-like vClub cells by promoting their proliferation during ovalbumin-induced acute inflammation. Mechanistically, impaired autophagy disrupted glucose uptake in vClub progenitor cells, and either reduced accessibility to glucose or partial inhibition of glycolysis promoted the proliferative capacity of vClub progenitor cells and their daughter Club cells. However, glucose deprivation or glycolysis blockade abrogated the proliferative capacity of airway vClub cells and Club cells but promoted ciliated and goblet cell differentiation. Deficiency of glucose transporter-1 suppressed the proliferative capacity of airway progenitor cells after ovalbumin challenge. These findings suggested that autophagy and glucose metabolism are essential for the maintenance of airway epithelium at steady state and during allergic inflammation.


2020 ◽  
Vol 53 (1) ◽  
Author(s):  
Yuri Okazaki ◽  
Jennifer Murray ◽  
Ali Ehsani ◽  
Jessica Clark ◽  
Robert H. Whitson ◽  
...  

Abstract Background Skeletal muscle has an important role in regulating whole-body energy homeostasis, and energy production depends on the efficient function of mitochondria. We demonstrated previously that AT-rich interactive domain 5b (Arid5b) knockout (Arid5b−/−) mice were lean and resistant to high-fat diet (HFD)-induced obesity. While a potential role of Arid5b in energy metabolism has been suggested in adipocytes and hepatocytes, the role of Arid5b in skeletal muscle metabolism has not been studied. Therefore, we investigated whether energy metabolism is altered in Arid5b−/− skeletal muscle. Results Arid5b−/− skeletal muscles showed increased basal glucose uptake, glycogen content, glucose oxidation and ATP content. Additionally, glucose clearance and oxygen consumption were upregulated in Arid5b−/− mice. The expression of glucose transporter 1 (GLUT1) and 4 (GLUT4) in the gastrocnemius (GC) muscle remained unchanged. Intriguingly, the expression of TBC domain family member 1 (TBC1D1), which negatively regulates GLUT4 translocation to the plasma membrane, was suppressed in Arid5b−/− skeletal muscle. Coimmunofluorescence staining of the GC muscle sections for GLUT4 and dystrophin revealed increased GLUT4 localization at the plasma membrane in Arid5b−/− muscle. Conclusions The current study showed that the knockout of Arid5b enhanced glucose metabolism through the downregulation of TBC1D1 and increased GLUT4 membrane translocation in skeletal muscle.


VASA ◽  
2013 ◽  
Vol 42 (1) ◽  
pp. 8-16 ◽  
Author(s):  
Mario Chiong ◽  
Pablo E. Morales ◽  
Gloria Torres ◽  
Tomás Gutiérrez ◽  
Lorena García ◽  
...  

Differentiation of vascular smooth muscle cells (VSMC) is an essential process of vascular development. VSMC have biosynthetic, proliferative, and contractile roles in the vessel wall. Alterations in the differentiated state of the VSMC play a critical role in the pathogenesis of atherosclerosis and intimal hyperplasia, as well as in a variety of other human diseases, including hypertension, asthma, atherosclerosis and vascular aneurysm. This review provides an overview of the current state of knowledge of molecular mechanisms involved in controlling VSMC proliferation, with particular focus on glucose metabolism and its relationship with mitochondrial bioenergetics. Increased levels of glucose transporter 1 (GLUT1) are observed in VSMC after endothelial injury, suggesting a relationship between glucose uptake and VSMC proliferation. Mitochondrial dysfunction is a common feature in VSMC during atherosclerosis. Alterations in mitochondrial function can be produced by dysregulation of mitofusin-2, a small GTPase associated with mitochondrial fusion. Moreover, exacerbated proliferation was observed in VSMC from pulmonary arteries with hyperpolarized mitochondria and enhanced glycolysis/glucose oxidation ratio. Several lines of evidence highlight the relevance of glucose metabolism in the control of VSMC proliferation, indicating a new area to be explored in the control of vascular pathogenesis.


2018 ◽  
Vol 314 (2) ◽  
pp. E115-E123 ◽  
Author(s):  
Ayumu Takeno ◽  
Ippei Kanazawa ◽  
Masakazu Notsu ◽  
Ken-ichiro Tanaka ◽  
Toshitsugu Sugimoto

Bone and glucose metabolism are closely associated with each other. Both osteoblast and osteoclast functions are important for the action of osteocalcin, which plays pivotal roles as an endocrine hormone regulating glucose metabolism. However, it is unknown whether osteocytes are involved in the interaction between bone and glucose metabolism. We used MLO-Y4-A2, a murine long bone-derived osteocytic cell line, to investigate effects of glucose uptake inhibition on expressions of osteocalcin and bone-remodeling modulators in osteocytes. We found that glucose transporter 1 (GLUT1) is expressed in MLO-Y4-A2 cells and that treatment with phloretin, a GLUT inhibitor, significantly inhibited glucose uptake. Real-time PCR and Western blot showed that phloretin significantly and dose-dependently decreased the expressions of RANKL and osteocalcin, whereas osteoprotegerin or sclerostin was not affected. Moreover, phloretin activated AMP-activated protein kinase (AMPK), an intracellular energy sensor. Coincubation of ara-A, an AMPK inhibitor, with phloretin canceled the phloretin-induced decrease in osteocalcin expression, but not RANKL. In contrast, phloretin suppressed phosphorylation of ERK1/2, JNK, and p38 MAPK, and treatments with the p38 inhibitor SB203580 and the MEK inhibitor PD98059, but not the JNK inhibitor SP600125, significantly decreased expressions of RANKL and osteocalcin. These results indicate that glucose uptake by GLUT1 is required for RANKL and osteocalcin expressions in osteocytes, and that inhibition of glucose uptake decreases their expressions through AMPK, ERK1/2, and p38 MAPK pathways. These findings suggest that lowering glucose uptake into osteocytes may contribute to maintain blood glucose levels by decreasing osteocalcin expression and RANKL-induced bone resorption.


Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 505
Author(s):  
Ying-Yi Lu ◽  
Chieh-Hsin Wu ◽  
Chien-Hui Hong ◽  
Kee-Lung Chang ◽  
Chih-Hung Lee

A keloid is a fibroproliferative skin tumor. Proliferating keloid fibroblasts (KFs) demand active metabolic utilization. The contributing roles of glycolysis and glucose metabolism in keloid fibroproliferation remain unclear. This study aims to determine the regulation of glycolysis and glucose metabolism by glucose transporter-1 (GLUT-1), an essential protein to initiate cellular glucose uptake, in keloids and in KFs. Tissues of keloids and healthy skin were explanted for KFs and normal fibroblasts (NFs), respectively. GLUT-1 expression was measured by immunofluorescence, RT-PCR, and immunoblotting. The oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were measured with or without WZB117, a GLUT-1 inhibitor. Reactive oxygen species (ROS) were assayed by MitoSOX immunostaining. The result showed that glycolysis (ECAR) was enhanced in KFs, whereas OCR was not. GLUT-1 expression was selectively increased in KFs. Consistently, GLUT-1 expression was increased in keloid tissue. Treatment with WZB117 abolished the enhanced ECAR, including glycolysis and glycolytic capacity, in KFs. ROS levels were increased in KFs compared to those in NFs. GLUT-1 inhibition suppressed not only the ROS levels but also the cell proliferation in KFs. In summary, the GLUT-1-dependent glycolysis and ROS production mediated fibroblast proliferation in keloids. GLUT1 might be a potential target for metabolic reprogramming to treat keloids.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Naoto Mukada ◽  
Masahiko Tosaka ◽  
Nozomi Matsumura ◽  
Rei Yamaguchi ◽  
Masanori Aihara ◽  
...  

AbstractPapillary craniopharyngiomas are characterized by the BRAF V600E mutation. Enhancement of glucose metabolism may be involved in the downstream of the BRAF V600E mutation in many types of tumors. Glucose metabolism was investigated in craniopharyngioma using immunohistochemical analysis. The study included 29 cases of craniopharyngioma (18 adamantinomatous type [ACP], 11 papillary type [PCP]). Immunohistochemical analysis was performed with anti-glucose transporter-1 (GLUT-1), anti-hexokinase-II (HK-II), anti-BRAF V600E, and anti-beta-catenin antibodies. Expressions of GLUT-1 and HK-II were evaluated using a semiquantitative 4-tiered scale as 0, 1+, 2+, 3+, and divided into negative (0 or 1+) or positive (2+ or 3+) group. GLUT-1 expression level was significantly higher in PCPs than ACPs (0, 1+, 2+, 3+ = 2, 12, 4, 0 cases in ACP, respectively, 0, 1+, 2+, 3+ = 0, 2, 5, 4 in PCP, p = 0.001), and most PCPs were classified into positive group (positive rate, 22.2% [4/18] in ACP, 81.8% [9/11] in PCP; p = 0.003). HK-II expression was also conspicuous in PCPs (0, 1+, 2+, 3+ = 7, 9, 2, 0 cases in ACP, 0, 3, 3, 5 in PCP; p = 0.001), and most of them divided into positive group (positive rate, 11.1% [2/18] in ACP, 72.7% [8/11] in PCP; p = 0.001). Expression patterns of BRAF V600E and beta-catenin reflected the clinicopathological subtypes. Both GLUT-1 and HK-II expressions were prominent in PCP. Glucose metabolism might be more enhanced in PCP than ACP. PCP may use the glucose metabolic system downstream of the BRAF V600E mutant protein.


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