Effect of oocyte vitrification on glucose transport in mouse metaphase II oocytes

Reproduction ◽  
2021 ◽  
Vol 161 (5) ◽  
pp. 549-559
Author(s):  
Yufei Wang ◽  
Haoya Chang ◽  
Qifu He ◽  
Yaxing Xue ◽  
Kang Zhang ◽  
...  

Oocyte vitrification has significantly improved the survival rate and become the mainstream method for cryopreserving oocytes. Previous studies have demonstrated that the ultrastructure, mitochondrial function, DNA methylation, and histone modification exhibit an irreversible effect after oocyte vitrification. However, little is known about the effects of oocyte vitrification on glucose transport and metabolism. This study aims to determine whether mouse oocyte vitrification causes abnormal glucose metabolism and identify a strategy to correct abnormal glucose metabolism. Furthermore, this study further investigates the effects of oocyte vitrification on glucose uptake, and glucose metabolism, and energy levels. The results indicated that vitrification significantly reduced the glucose transport activity, NADPH, glutathione, and ATP levels, and increased reactive oxygen species levels in oocytes (P  < 0.01). Vitrification also reduced the expression of glucose transporter isoform 1 (GLUT1) (P  < 0.01). Adding a GLUT1 inhibitor reduced the glucose uptake capacity of oocytes. Furthermore, the inclusion of vitamin C into thawing and culture solutions restored abnormal glucose transportation and metabolism and improved the survival, two-cell embryo, and blastocyst rates of the vitrified groups via parthenogenesis (P  < 0.05). Overall, this method may improve the quality and efficiency of oocyte vitrification.

2021 ◽  
Author(s):  
Zhenyu Jiao ◽  
Yingqun Chen ◽  
Yang Xie ◽  
Yanbing Li ◽  
Zhi Li

Abstract BackgroundHigh uric acid (HUA) is associated with insulin resistance and abnormal glucose metabolism in cardiomyocytes. Metformin is a recognized agonist of AMP-activated protein kinase (AMPK) and an antidiabetic drug widely used for type 2 diabetes. It can play a cardioprotective role in many pathways. We investigated whether metformin protects against HUA-induced insulin resistance and abnormal glucose metabolism in cardiomyocytes.MethodsWe exposed primary cardiomyocytes to HUA, and cellular glucose uptake was quantified by measuring the uptake of 2-NBDG, a fluorescent glucose analog, after insulin excitation.ResultsTreatment with metformin (10 µmol/L) protected against HUA-inhibited glucose uptake induced by insulin in primary cardiomyocytes, as shown by fluorescence microscopy and flow cytometry analysis. HUA directly inhibited the phosphorylation of Akt and the translocation of glucose transporter type 4 (GLUT4) induced by insulin, which was blocked by metformin. Metformin promoted phosphorylation of AMPK, renewed HUA-inhibited glucose uptake induced by insulin and protected against insulin resistance in cardiomyocytes. As a result of these effects, in a mouse model of acute hyperuricemia, metformin improved insulin tolerance and glucose tolerance, accompanied by increased AMPK phosphorylation, Akt phosphorylation and translocation of GLUT4 in myocardial tissues. As expected, AICAR, another AMPK activator, had equivalent effects to metformin, demonstrating the important role of AMPK activation in protecting against insulin resistance induced by HUA in cardiomyocytes. Metformin protects against insulin resistance induced by HUA in cardiomyocytes and improves insulin tolerance and glucose tolerance in an acute hyperuricemic mouse model, along with the activation of AMPK.ConclusionsConsequently, metformin may be an important potential new treatment strategy for hyperuricemia-related cardiovascular disease.


2021 ◽  
Author(s):  
Zhenyu Jiao ◽  
Yingqun Chen ◽  
Yang Xie ◽  
Yanbing Li ◽  
Zhi Li

AbstractHigh uric acid (HUA) is associated with insulin resistance and abnormal glucose metabolism in cardiomyocytes. Metformin is a recognized agonist of AMP-activated protein kinase (AMPK) and an antidiabetic drug widely used for type 2 diabetes. It can play a cardioprotective role in many pathways. We investigated whether metformin protects against HUA-induced insulin resistance and abnormal glucose metabolism in cardiomyocytes. We exposed primary cardiomyocytes to HUA, and cellular glucose uptake was quantified by measuring the uptake of 2-NBDG, a fluorescent glucose analog, after insulin excitation. Treatment with metformin (10 μmol/L) protected against HUA-inhibited glucose uptake induced by insulin in primary cardiomyocytes, as shown by fluorescence microscopy and flow cytometry analysis. HUA directly inhibited the phosphorylation of Akt and the translocation of glucose transporter type 4 (GLUT4) induced by insulin, which was blocked by metformin. Metformin promoted phosphorylation of AMPK, renewed HUA-inhibited glucose uptake induced by insulin and protected against insulin resistance in cardiomyocytes. As a result of these effects, in a mouse model of acute hyperuricemia, metformin improved insulin tolerance and glucose tolerance, accompanied by increased AMPK phosphorylation, Akt phosphorylation and translocation of GLUT4 in myocardial tissues. As expected, AICAR, another AMPK activator, had equivalent effects to metformin, demonstrating the important role of AMPK activation in protecting against insulin resistance induced by HUA in cardiomyocytes. Metformin protects against insulin resistance induced by HUA in cardiomyocytes and improves insulin tolerance and glucose tolerance in an acute hyperuricemic mouse model, along with the activation of AMPK. Consequently, metformin may be an important potential new treatment strategy for hyperuricemia-related cardiovascular disease.


2021 ◽  
Author(s):  
Yan Peng ◽  
Li Zhang ◽  
Fanlin Zhou ◽  
Yangyang Wang ◽  
Shijie Li ◽  
...  

Abstract Dysregulated glucose metabolism in the brain is considered to be the underlying cause of Alzheimer's disease (AD). Abnormal glucose metabolism in AD is associated with decreased glucose transporter 1 (GLUT1) and GLUT3 in the brain, but the underlying mechanisms remains unclear. Here, we reported that GLUT1 expression was decreased in N2a/APP695swe cells and GLUT3 expression was not significantly changed. Flow Cytometry analysis showed a significant increase of intracellular ROS content in N2a/APP695swe cells and GLUT1 expression was upregulated after treatment with the ROS scavenger N-acetyl-L-Cysteine (NAC). Cellular glucose uptake and ATP levels were reduced following decreased GLUT1 expression and increased after upregulating GLUT1. Western blot analyses showed that phosphorylation of PI3K/Akt pathway decreased in N2a/APP695swe cells. Aβ levels decreased after upregulation of GLUT1 expression and increased after downregulation of GLUT1. After NAC treatment, PI3K/Akt pathway phosphorylation levels and GLUT1 expression were upregulated, glucose uptake and ATP contents were increased, and Aβ levels were decreased. After adding PI3K/Akt pathway inhibitor LY29004, GLUT1 expression was reduced and Aβ levels were increased. Besides, the increased glucose uptake and ATP contents by the Akt activator SC79 were hindered with the GLUT1 inhibitor WZB117. Aβ levels decreased after SC79 treatment and increased after WZB117 treatment. Overall, our data suggest that ROS reduced GLUT1 expression by inhibiting PI3K/Akt pathway activity resulting in impaired glucose metabolism and scavenging ROS prevents Aβ via activation of PI3K/Akt/GLUT1 pathway in N2a/APP695swe cells.


2021 ◽  
Author(s):  
Zhi Li ◽  
Zhenyu Jiao ◽  
Yingqun Chen ◽  
Yang Xie ◽  
Yanbing Li

Abstract High uric acid (HUA) is associated with insulin resistance and abnormal glucose metabolism in cardiomyocytes. Metformin is a recognized agonist of AMP-activated protein kinase (AMPK) and an antidiabetic drug widely used for type 2 diabetes. It can play a cardioprotective role in many pathways. We investigated whether metformin protects against HUA-induced insulin resistance and abnormal glucose metabolism in cardiomyocytes. We exposed primary cardiomyocytes to HUA, and cellular glucose uptake was quantified by measuring the uptake of 2-NBDG, a fluorescent glucose analog, after insulin excitation. Treatment with metformin (10 μmol/L) protected against HUA-inhibited glucose uptake induced by insulin in primary cardiomyocytes, as shown by fluorescence microscopy and flow cytometry analysis. HUA directly inhibited the phosphorylation of Akt and the translocation of glucose transporter type 4 (GLUT4) induced by insulin, which was blocked by metformin. Metformin promoted phosphorylation of AMPK, renewed HUA-inhibited glucose uptake induced by insulin and protected against insulin resistance in cardiomyocytes. As a result of these effects, in a mouse model of acute hyperuricemia, metformin improved insulin tolerance and glucose tolerance, accompanied by increased AMPK phosphorylation, Akt phosphorylation and translocation of GLUT4 in myocardial tissues. As expected, AICAR, another AMPK activator, had equivalent effects to metformin, demonstrating the important role of AMPK activation in protecting against insulin resistance induced by HUA in cardiomyocytes. Metformin protects against insulin resistance induced by HUA in cardiomyocytes and improves insulin tolerance and glucose tolerance in an acute hyperuricemic mouse model, along with the activation of AMPK. Consequently, metformin may be an important potential new treatment strategy for hyperuricemia-related cardiovascular disease.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Monira Obaid ◽  
S. M. Nashir Udden ◽  
Prasanna Alluri ◽  
Subhrangsu S. Mandal

AbstractInflammation plays central roles in the immune response. Inflammatory response normally requires higher energy and therefore is associated with glucose metabolism. Our recent study demonstrates that lncRNA HOTAIR plays key roles in NF-kB activation, cytokine expression, and inflammation. Here, we investigated if HOTAIR plays any role in the regulation of glucose metabolism in immune cells during inflammation. Our results demonstrate that LPS-induced inflammation induces the expression of glucose transporter isoform 1 (Glut1) which controls the glucose uptake in macrophages. LPS-induced Glut1 expression is regulated via NF-kB activation. Importantly, siRNA-mediated knockdown of HOTAIR suppressed the LPS-induced expression of Glut1 suggesting key roles of HOTAIR in LPS-induced Glut1 expression in macrophage. HOTAIR induces NF-kB activation, which in turn increases Glut1 expression in response to LPS. We also found that HOTAIR regulates glucose uptake in macrophages during LPS-induced inflammation and its knockdown decreases LPS-induced increased glucose uptake. HOTAIR also regulates other upstream regulators of glucose metabolism such as PTEN and HIF1α, suggesting its multimodal functions in glucose metabolism. Overall, our study demonstrated that lncRNA HOTAIR plays key roles in LPS-induced Glut1 expression and glucose uptake by activating NF-kB and hence HOTAIR regulates metabolic programming in immune cells potentially to meet the energy needs during the immune response.


2021 ◽  
Vol 22 (13) ◽  
pp. 7228
Author(s):  
Ching-Chia Wang ◽  
Huang-Jen Chen ◽  
Ding-Cheng Chan ◽  
Chen-Yuan Chiu ◽  
Shing-Hwa Liu ◽  
...  

Urinary acrolein adduct levels have been reported to be increased in both habitual smokers and type-2 diabetic patients. The impairment of glucose transport in skeletal muscles is a major factor responsible for glucose uptake reduction in type-2 diabetic patients. The effect of acrolein on glucose metabolism in skeletal muscle remains unclear. Here, we investigated whether acrolein affects muscular glucose metabolism in vitro and glucose tolerance in vivo. Exposure of mice to acrolein (2.5 and 5 mg/kg/day) for 4 weeks substantially increased fasting blood glucose and impaired glucose tolerance. The glucose transporter-4 (GLUT4) protein expression was significantly decreased in soleus muscles of acrolein-treated mice. The glucose uptake was significantly decreased in differentiated C2C12 myotubes treated with a non-cytotoxic dose of acrolein (1 μM) for 24 and 72 h. Acrolein (0.5–2 μM) also significantly decreased the GLUT4 expression in myotubes. Acrolein suppressed the phosphorylation of glucose metabolic signals IRS1, Akt, mTOR, p70S6K, and GSK3α/β. Over-expression of constitutive activation of Akt reversed the inhibitory effects of acrolein on GLUT4 protein expression and glucose uptake in myotubes. These results suggest that acrolein at doses relevant to human exposure dysregulates glucose metabolism in skeletal muscle cells and impairs glucose tolerance in mice.


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.


2001 ◽  
Vol 226 (4) ◽  
pp. 283-295 ◽  
Author(s):  
Robert V. Farese

Insulin provokes rapid changes in phospholipid metabolism and thereby generates biologically active lipids that serve as intracellular signaling factors that regulate glucose transport and glycogen synthesis. These changes include: (i) activation of phosphatidylinositol 3-kinase (PI3K) and production of PIP3; (ii) PIP3-dependent activation of atypical protein kinase Cs (PKCs); (iii) PIP3-dependent activation of PKB; (iv) PI3K-dependent activation of phospholipase D and hydrolysis of phosphatidyicholine with subsequent increases in phosphatidic acid (PA) and diacyiglycerol (DAG); (v) PI3K-independent activation of glycerol-3-phosphate acylytansferase and increases in de novo synthesis of PA and DAG; and (vi) activation of DAG-sensitive PKCs. Recent findings suggest that atypical PKCs and PKB serve as important positive regulators of insulin-stimulated glucose metabolism, whereas mechanisms that result in the activation of DAG-sensitive PKCs serve mainly as negative regulators of insulin signaling through PI3K. Atypical PKCs and PKB are rapidly activated by insulin in adipocytes, liver, skeletal muscles, and other cell types by a mechanism requiring PI3K and its downstream effector, 3-phosphoinositide-dependent protein kinase-1 (PDK-1), which, in conjunction with PIP3, phosphorylates critical threonine residues in the activation loops of atypical PKCs and PKB. PIP3 also promotes increases in autophosphorylation and allosteric activation of atypical PKCs. Atypical PKCs and perhaps PKB appear to be required for insulin-induced translocation of the GLUT 4 glucose transporter to the plasma membrane and subsequent glucose transport. PKB also appears to be the major regulator of glycogen synthase. Together, atypical PKCs and PKB serve as a potent, integrated PI3K/PDK-1-directed signaling system that is used by insulin to regulate glucose metabolism.


1997 ◽  
Vol 273 (3) ◽  
pp. C1082-C1087 ◽  
Author(s):  
A. D. Lee ◽  
P. A. Hansen ◽  
J. Schluter ◽  
E. A. Gulve ◽  
J. Gao ◽  
...  

beta-Adrenergic stimulation has been reported to inhibit insulin-stimulated glucose transport in adipocytes. This effect has been attributed to a decrease in the intrinsic activity of the GLUT-4 isoform of the glucose transporter that is mediated by phosphorylation of GLUT-4. Early studies showed no inhibition of insulin-stimulated glucose transport by epinephrine in skeletal muscle. The purpose of this study was to determine the effect of epinephrine on GLUT-4 phosphorylation, and reevaluate the effect of beta-adrenergic stimulation on insulin-activated glucose transport, in skeletal muscle. We found that 1 microM epinephrine, which raised adenosine 3',5'-cyclic monophosphate approximately ninefold, resulted in GLUT-4 phosphorylation in rat skeletal muscle but had no inhibitory effect on insulin-stimulated 3-O-methyl-D-glucose (3-MG) transport. In contrast to 3-MG transport, the uptakes of 2-deoxyglucose and glucose were markedly inhibited by epinephrine treatment. This inhibitory effect was presumably mediated by stimulation of glycogenolysis, which resulted in an increase in glucose 6-phosphate concentration to levels known to severely inhibit hexokinase. We conclude that 1) beta-adrenergic stimulation decreases glucose uptake by raising glucose 6-phosphate concentration, thus inhibiting hexokinase, but does not inhibit insulin-stimulated glucose transport and 2) phosphorylation of GLUT-4 has no effect on glucose transport in skeletal muscle.


1995 ◽  
Vol 269 (6) ◽  
pp. E1052-E1058 ◽  
Author(s):  
R. Potashnik ◽  
N. Kozlovsky ◽  
S. Ben-Ezra ◽  
A. Rudich ◽  
N. Bashan

Possible association between the degree of iron load and glucose metabolism has been postulated by both in vivo and in vitro studies. Because skeletal muscle plays a major role in whole body glucose utilization, we evaluated the effect of iron chelators deferoxamine (DFO) and bipyridyl (Bip) on glucose metabolism and transport in cultured L6 muscle cells. Bip (0.1 mM) or DFO (0.5 mM) added for 24 h to the culture medium increased glucose consumption, lactate production, and [14C]glucose incorporation into glycogen by approximately twofold. 2-Deoxy-glucose uptake by L6 myotubes increased time dependently, reaching a 5-fold and 2.5-fold increase after 12 h for Bip and DFO, respectively. Insulin induced a 2.5-fold increase in glucose uptake in untreated cells, which was additive to the chelator's effect. Iron chelator-induced glucose transport stimulation was inhibited by cycloheximide (2.5 micrograms/ml), indicating dependence on de novo protein synthesis. Increases in GLUT-1 protein and mRNA concentration, without changes in GLUT-4, were found to be responsible for iron chelator effects. We conclude that L6 cells adapt to reduction in iron availability by increasing glucose utilization through an enhanced expression of GLUT-1, without losing their physiological response to insulin.


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