WorldWideScience

Sample records for high glucose inhibits

  1. High glucose promotes Aβ production by inhibiting APP degradation.

    Directory of Open Access Journals (Sweden)

    Yi Yang

    Full Text Available Abnormal deposition of neuriticplaques is the uniqueneuropathological hallmark of Alzheimer's disease (AD.Amyloid β protein (Aβ, the major component of plaques, is generated from sequential cleavage of amyloidβ precursor protein (APP by β-secretase and γ-secretase complex. Patients with diabetes mellitus (DM, characterized by chronic hyperglycemia,have increased risk of AD development.However, the role of high blood glucose in APP processing and Aβ generation remains elusive. In this study, we investigated the effect of high glucose on APP metabolism and Aβ generation in cultured human cells. We found that high glucose treatment significantly increased APP protein level in both neuronal-like and non-neuronal cells, and promoted Aβ generation. Furthermore, we found that high glucose-induced increase of APP level was not due to enhancement of APP gene transcription but resulted from inhibition of APP protein degradation. Taken together, our data indicated that hyperglycemia could promote AD pathogenesis by inhibiting APP degradation and enhancing Aβ production. More importantly, the elevation of APP level and Aβ generation by high glucose was caused by reduction of APP turnover rate.Thus,our study provides a molecular mechanism of increased risk of developing AD in patients withDMand suggests thatglycemic control might be potentially beneficial for reducing the incidence of AD in diabetic patients and delaying the AD progression.

  2. Propofol inhibits high glucose-induced PP2A expression in human umbilical vein endothelial cells.

    Science.gov (United States)

    Wu, Qichao; Zhao, Yanjun; Duan, Wenming; Liu, Yi; Chen, Xiangyuan; Zhu, Minmin

    2017-04-01

    Perioperative hyperglycemia is a common clinical metabolic disorder. Hyperglycemia could induce endothelial apoptosis, dysfunction and inflammation, resulting in endothelial injury. Propofol is a widely used anesthetic drug in clinical settings. Our previous studies indicated that propofol, via inhibiting high glucose-induced phosphatase A2 (PP2A) expression, attenuated high glucose-induced reactive oxygen species (ROS) accumulation, thus improving endothelial apoptosis, dysfunction and inflammation. However, the mechanisms by which propofol attenuated high glucose-induced PP2A expression is still obscure. In the present study, we examined how propofol attenuates high glucose-induced endothelial PP2A expression. Compared with 5mM glucose treatment, 15mM glucose up-regulated expression and activity of PP2A, increased cAMP response element binding protein (CREB), Ca(2+)-calmodulin dependent kinase II (CaMK II) phosphorylation and Ca(2+) accumulation. More importantly, propofol decreased PP2A expression and activity, attenuated CREB, CaMK II phosphorylation and Ca(2+) accumulation in a concentration-dependent manner. Moreover, we demonstrated that the effect of propofol was similar to that of MK801, an inhibitor of NMDA receptor. In contrast, rapastinel, an activator of NMDA receptor, antagonized the effect of propofol. Also, the effect of KN93, an inhibitor of CaMK II, was similar to that of propofol, except KN93 had no effect on 15mM glucose-mediated Ca(2+) accumulation. Our data indicated that propofol, via inhibiting NMDA receptor, attenuated 15mM glucose-induced Ca(2+) accumulation, CaMK II and CREB phosphorylation, thus inhibiting PP2A expression and improving 15mM glucose-induced endothelial dysfunction and inflammation. Copyright © 2017 Elsevier Inc. All rights reserved.

  3. High Glucose Represses hERG K+ Channel Expression through Trafficking Inhibition

    Directory of Open Access Journals (Sweden)

    Yuan-Qi Shi

    2015-08-01

    Full Text Available Background/Aims: Abnormal QT prolongation is the most prominent cardiac electrical disturbance in patients with diabetes mellitus (DM. It is well known that the human ether-ago-go-related gene (hERG controls the rapid delayed rectifier K+ current (IKr in cardiac cells. The expression of the hERG channel is severely down-regulated in diabetic hearts, and this down-regulation is a critical contributor to the slowing of repolarization and QT prolongation. However, the intracellular mechanisms underlying the diabetes-induced hERG deficiency remain unknown. Methods: The expression of the hERG channel was assessed via western blot analysis, and the hERG current was detected with a patch-clamp technique. Results: The results of our study revealed that the expression of the hERG protein and the hERG current were substantially decreased in high-glucose-treated hERG-HEK cells. Moreover, we demonstrated that the high-glucose-mediated damage to the hERG channel depended on the down-regulation of protein levels but not the alteration of channel kinetics. These discoveries indicated that high glucose likely disrupted hERG channel trafficking. From the western blot and immunoprecipitation analyses, we found that high glucose induced trafficking inhibition through an effect on the expression of Hsp90 and its interaction with hERG. Furthermore, the high-glucose-induced inhibition of hERG channel trafficking could activate the unfolded protein response (UPR by up-regulating the expression levels of activating transcription factor-6 (ATF-6 and the ER chaperone protein calnexin. In addition, we demonstrated that 100 nM insulin up-regulated the expression of the hERG channel and rescued the hERG channel repression caused by high glucose. Conclusion: The results of our study provide the first evidence of a high-glucose-induced hERG channel deficiency resulting from the inhibition of channel trafficking. Furthermore, insulin promotes the expression of the hERG channel

  4. ALDH2 Inhibition Potentiates High Glucose Stress-Induced Injury in Cultured Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Guodong Pan

    2016-01-01

    Full Text Available Aldehyde dehydrogenase (ALDH gene superfamily consists of 19 isozymes. They are present in various organs and involved in metabolizing aldehydes that are biologically generated. For instance, ALDH2, a cardiac mitochondrial ALDH isozyme, is known to detoxify 4-hydroxy-2-nonenal, a reactive aldehyde produced upon lipid peroxidation in diabetic conditions. We hypothesized that inhibition of ALDH leads to the accumulation of unmetabolized 4HNE and consequently exacerbates injury in cells subjected to high glucose stress. H9C2 cardiomyocyte cell lines were pretreated with 10 μM disulfiram (DSF, an inhibitor of ALDH2 or vehicle (DMSO for 2 hours, and then subjected to high glucose stress {33 mM D-glucose (HG or 33 mM D-mannitol as an osmotic control (Ctrl} for 24 hrs. The decrease in ALDH2 activity with DSF pretreatment was higher in HG group when compared to Ctrl group. Increased 4HNE adduct formation with DSF pretreatment was higher in HG group compared to Ctrl group. Pretreatment with DSF leads to potentiated HG-induced cell death in cultured H9C2 cardiomyocytes by lowering mitochondrial membrane potential. Our results indicate that ALDH2 activity is important in preventing high glucose induced cellular dysfunction.

  5. High glucose disrupts oligosaccharide recognition function via competitive inhibition: a potential mechanism for immune dysregulation in diabetes mellitus.

    Science.gov (United States)

    Ilyas, Rebecca; Wallis, Russell; Soilleux, Elizabeth J; Townsend, Paul; Zehnder, Daniel; Tan, Bee K; Sim, Robert B; Lehnert, Hendrik; Randeva, Harpal S; Mitchell, Daniel A

    2011-01-01

    Diabetic complications include infection and cardiovascular disease. Within the immune system, host-pathogen and regulatory host-host interactions operate through binding of oligosaccharides by C-type lectin. A number of C-type lectins recognise oligosaccharides rich in mannose and fucose - sugars with similar structures to glucose. This raises the possibility that high glucose conditions in diabetes affect protein-oligosaccharide interactions via competitive inhibition. Mannose-binding lectin, soluble DC-SIGN and DC-SIGNR, and surfactant protein D, were tested for carbohydrate binding in the presence of glucose concentrations typical of diabetes, via surface plasmon resonance and affinity chromatography. Complement activation assays were performed in high glucose. DC-SIGN and DC-SIGNR expression in adipose tissues was examined via immunohistochemistry. High glucose inhibited C-type lectin binding to high-mannose glycoprotein and binding of DC-SIGN to fucosylated ligand (blood group B) was abrogated in high glucose. Complement activation via the lectin pathway was inhibited in high glucose and also in high trehalose - a nonreducing sugar with glucoside stereochemistry. DC-SIGN staining was seen on cells with DC morphology within omental and subcutaneous adipose tissues. We conclude that high glucose disrupts C-type lectin function, potentially illuminating new perspectives on susceptibility to infectious and inflammatory disease in diabetes. Mechanisms involve competitive inhibition of carbohydrate binding within sets of defined proteins, in contrast to broadly indiscriminate, irreversible glycation of proteins.

  6. Conditions With High Intracellular Glucose Inhibit Sensing Through Glucose Sensor Snf3 in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Karhumaa, Kaisa; Wu, B.Q.; Kielland-Brandt, Morten

    2010-01-01

    Gene expression in micro-organisms is regulated according to extracellular conditions and nutrient concentrations. In Saccharomyces cerevisiae, non-transporting sensors with high sequence similarity to transporters, that is, transporter-like sensors, have been identified for sugars as well...

  7. Puerarin prevents high glucose-induced apoptosis of Schwann cells by inhibiting oxidative stress

    Institute of Scientific and Technical Information of China (English)

    Yingying Wu; Bing Xue; Xiaojin Li; Hongchen Liu

    2012-01-01

    Oxidative stress may be the unifying factor for the injury caused by hyperglycemia in diabeticperipheral neuropathy.Puerarin is the major isoflavonoid derived from Radix puerariae and has been shown to be effective in increasing superoxide dismutase activity.This study sought to investigate the neuroprotective effect of puerarin on high glucose-induced oxidative stress and Schwann cell apoptosis in vitro.Intracellular reactive oxygen radicals and mitochondrial transmembrane potential were detected by flow cytometry analysis.Apoptosis was confirmed by TUNEL and oxidative stress was monitored using an enzyme-linked immunosorbent assay for the DNA marker 8-hydroxy-2-deoxyguanosine.The expression levels of bax and bcl-2 were analyzed by quantitative real-time reverse transcriptase-PCR,while protein expression of cleaved caspase-3 and-9 were analyzed by means of western blotting.Results suggested that puerarin treatment inhibited high glucose-induced oxidative stress,mitochondrial depolarization and apoptosis in a dose-dependent manner.Furthermore,puerarin treatment downregulated Bax expression,upregulated bcl-2 expression and attenuated the activation of caspase-3 and-9.Overall,our results indicated that puerarin antagonized high glucose-induced oxidative stress and apoptosis in Schwann cells.

  8. Scutellarein inhibits hypoxia- and moderately-high glucose-induced proliferation and VEGF expression in human retinal endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Rong GAO; Bang-hao ZHU; Shi-bo TANG; Jiang-feng WANG; Jun REN

    2008-01-01

    Aim: This study was designed to examine the effect of scutellarein on high glu-cose- and hypoxia-stimulated proliferation of human retinal endothelial cells (HREC). Methods: HREC were cultured under normal glucose (NG), moderate, and high glucose (NG supplemented with 10 or 25 mmol/L D-glucose) and/or hypoxic (cobalt chloride treated) conditions. Cell proliferation was evaluated by a cell counting kit. The expression of vascular endothelial growth factor (VEGF) was assessed by Western blot analysis. Results: The proliferation of HREC was significantly elevated in response to moderately-high glucose and hypoxic conditions. The combination of high glucose and hypoxia did not have any additive effects on cell proliferation. Consistent with the proliferation data, the expression of VEGF was also upregulated under both moderately-high glucose and hypoxic conditions. The treatment with scutellarein (1 × 10-11-1 × 10-5 mol/L) significantly inhibited high glucose- or hypoxia-induced cell proliferation and VEGF expression. Conclusion: Both hypoxia and moderately-high glucose were potent stimuli for cell proliferation and VEGF expression in HREC without any significant additive effects. Scutellarein is capable of inhibiting the proliferation of HREC, which is possibly related to its ability to suppress the VEGF expression.

  9. Thioredoxin-mimetic peptides (TXM) inhibit inflammatory pathways associated with high-glucose and oxidative stress.

    Science.gov (United States)

    Lejnev, Katia; Khomsky, Lena; Bokvist, Krister; Mistriel-Zerbib, Shani; Naveh, Tahel; Farb, Thomas Bradley; Alsina-Fernandez, Jorge; Atlas, Daphne

    2016-10-01

    Impaired insulin signaling and the associated insulin-resistance in liver, adipose tissue, and skeletal muscle, represents a hallmark of the pathogenesis of type 2-diabetes-mellitus. Here we show that in the liver of db/db mice, a murine model of obesity, type 2 diabetes, and dyslipidemia, the elevated activities of mitogen-activated protein kinases (MAPK; ERK1/2 and p38(MAPK)), and Akt/PKB are abolished by rosiglitazone-treatment, which normalizes blood glucose in db/db mice. This is unequivocal evidence of a functional link between the activation of the MAPK specific inflammatory-pathway and high-blood sugar. A similar reduction in ERK1/2, p38(MAPK), and Akt activities but without affecting blood-glucose was observed in the liver of db/db mice treated with a molecule that mimics the action of thioredoxin, called thioredoxin-mimetic peptide (TXM). N-Acetyl-Cys-Pro-Cys-amide (TXM-CB3) is a free radical scavenger, a reducing and denitrosylating reagent that protects the cells from early death induced by inflammatory pathways. TXM-CB3 also lowered MAPK signaling activated by the disruption of the thioredoxin-reductase-thioredoxin (Trx-TrxR) redox-system and restored Akt activity in rat hepatoma FAO cells. Similarly, two other TXM-peptides, N-Acetyl-Cys-Met-Lys-Cys-amide (TXM-CB13; DY70), and N-Acetyl-Cys-γGlu-Cys-Cys-amide (TXM-CB16; DY71), lowered insulin- and oxidative stress-induced ERK1/2 activation, and rescued HepG2 cells from cell death. The potential impact of TXM-peptides on inhibiting inflammatory pathways associated with high-glucose could be effective in reversing low-grade inflammation. TXM-peptides might also have the potential to improve insulin resistance by protecting from posttranslational modifications like nitrosylation. Copyright © 2016 Elsevier Inc. All rights reserved.

  10. Cathepsin inhibition-induced lysosomal dysfunction enhances pancreatic beta-cell apoptosis in high glucose.

    Science.gov (United States)

    Jung, Minjeong; Lee, Jaemeun; Seo, Hye-Young; Lim, Ji Sun; Kim, Eun-Kyoung

    2015-01-01

    Autophagy is a lysosomal degradative pathway that plays an important role in maintaining cellular homeostasis. We previously showed that the inhibition of autophagy causes pancreatic β-cell apoptosis, suggesting that autophagy is a protective mechanism for the survival of pancreatic β-cells. The current study demonstrates that treatment with inhibitors and knockdown of the lysosomal cysteine proteases such as cathepsins B and L impair autophagy, enhancing the caspase-dependent apoptosis of INS-1 cells and islets upon exposure to high concentration of glucose. Interestingly, treatment with cathepsin B and L inhibitors prevented the proteolytic processing of cathepsins B, D and L, as evidenced by gradual accumulation of the respective pro-forms. Of note, inhibition of aspartic cathepsins had no effect on autophagy and cell viability, suggesting the selective role of cathepsins B and L in the regulation of β-cell autophagy and apoptosis. Lysosomal localization of accumulated pro-cathepsins in the presence of cathepsin B and L inhibitors was verified via immunocytochemistry and lysosomal fractionation. Lysotracker staining indicated that cathepsin B and L inhibitors led to the formation of severely enlarged lysosomes in a time-dependent manner. The abnormal accumulation of pro-cathepsins following treatment with inhibitors of cathepsins B and L suppressed normal lysosomal degradation and the processing of lysosomal enzymes, leading to lysosomal dysfunction. Collectively, our findings suggest that cathepsin defects following the inhibition of cathepsin B and L result in lysosomal dysfunction and consequent cell death in pancreatic β-cells.

  11. High glucose inhibits ClC-2 chloride channels and attenuates cell migration of rat keratinocytes.

    Science.gov (United States)

    Pan, Fuqiang; Guo, Rui; Cheng, Wenguang; Chai, Linlin; Wang, Wenping; Cao, Chuan; Li, Shirong

    2015-01-01

    Accumulating evidence has demonstrated that migration of keratinocytes is critical to wound epithelialization, and defects of this function result in chronic delayed-healing wounds in diabetes mellitus patients, and the migration has been proved to be associated with volume-activated chloride channels. The aim of the study is to investigate the effects of high glucose (HG, 25 mM) on ClC-2 chloride channels and cell migration of keratinocytes. Newborn Sprague Dawley rats were used to isolate and culture the keratinocyte in this study. Immunofluorescence assay, real-time polymerase chain reaction, and Western blot assay were used to examine the expression of ClC-2 protein or mRNA. Scratch wound assay was used to measure the migratory ability of keratinocytes. Transwell cell migration assay was used to measure the invasion and migration of keratinocytes. Recombinant lentivirus vectors were established and transducted to keratinocytes. Whole-cell patch clamp was used to perform the electrophysiological studies. We found that the expression of ClC-2 was significantly inhibited when keratinocytes were exposed to a HG (25 mM) medium, accompanied by the decline of volume-activated Cl(-) current (I Cl,vol), migration potential, and phosphorylated PI3K as compared to control group. When knockdown of ClC-2 by RNAi or pretreatment with wortmannin, similar results were observed, including I Cl,vol and migration keratinocytes were inhibited. Our study proved that HG inhibited ClC-2 chloride channels and attenuated cell migration of rat keratinocytes via inhibiting PI3K signaling.

  12. Erythropoietin inhibits gluconeogenesis and inflammation in the liver and improves glucose intolerance in high-fat diet-fed mice.

    Directory of Open Access Journals (Sweden)

    Ran Meng

    Full Text Available Erythropoietin (EPO has multiple biological functions, including the modulation of glucose metabolism. However, the mechanisms underlying the action of EPO are still obscure. This study is aimed at investigating the potential mechanisms by which EPO improves glucose tolerance in an animal model of type 2 diabetes. Male C57BL/6 mice were fed with high-fat diet (HFD for 12 weeks and then treated with EPO (HFD-EPO or vehicle saline (HFD-Con for two week. The levels of fasting blood glucose, serum insulin and glucose tolerance were measured and the relative levels of insulin-related phosphatidylinositol 3-kinase (PI3K/Akt, insulin receptor (IR and IR substrate 1 (IRS1 phosphorylation were determined. The levels of phosphoenolpyruvate carboxykinase (PEPCK, glucose-6- phosphatase (G6Pase, toll like receptor 4 (TLR4, tumor necrosis factor (TNF-α and IL-6 expression and nuclear factor-κB (NF-κB and c-Jun N-terminal kinase (JNK, extracellular-signal-regulated kinase (ERK and p38 MAPK activation in the liver were examined. EPO treatment significantly reduced the body weights and the levels of fasting blood glucose and serum insulin and improved the HFD-induced glucose intolerance in mice. EPO treatment significantly enhanced the levels of Akt, but not IR and IRS1, phosphorylation, accompanied by inhibiting the PEPCK and G6Pase expression in the liver. Furthermore, EPO treatment mitigated the HFD-induced inflammatory TNF-α and IL-6 production, TLR4 expression, NF-κB and JNK, but not ERK and p38 MAPK, phosphorylation in the liver. Therefore, our data indicated that EPO treatment improved glucose intolerance by inhibiting gluconeogenesis and inflammation in the livers of HFD-fed mice.

  13. Chronic high glucose inhibits albumin reabsorption by lysosomal alkalinization in cultured porcine proximal tubular epithelial cells (LLC-PK1).

    Science.gov (United States)

    Ishibashi, Fukashi

    2006-06-01

    Lysosomal acidification is a key step of albumin reabsorption in proximal tubular epithelial cells (PTECs). This study was performed to examine the influence of chronic high glucose on lysosomal acidification in cultured PTECs. Porcine PTECs (LLC-PK(1) cells) were cultured in 16.7 mM (300 mg/dl) glucose (HG) alone or with 0.5 mM phlorizin for 24 weeks and subsequently for 12 weeks in 5.5 mM (100 mg/dl) glucose (NG). Chronic HG inhibited the fluorescein isothiocyanate (FITC)-albumin (A) uptake progressively, while phlorizin reversed the inhibition. NG for 12 weeks after HG normalized the uptake. The time-dependent uptake of FITC-A was inhibited by HG and bafilomycin A(1) (BafA(1)) after 15 min and by 4,4'-diisothiocyanato-2,2'-disulfonic acid (DIDS) and N-ethyl-N-isopropyl-amiloride (EIPA) after 3 min. Cellular ATP was depleted by HG and restored by NG. Lysosomal pH, assessed by an acidotropic fluorescent probe, was alkalinized (pH 4.5-7.8) with 5.5-27.8 mM glucose and normalized by subsequent NG. BafA(1) alkalinized lysosomes, and the concentration required to 50% change for the pH and 50% inhibition of FITC-A uptake was similar. EIPA inhibited FITC-A uptake, but did not influence lysosomal pH. DIDS inhibited FITC-A uptake, and unexpectedly lowered lysosomal pH. Real time PCR showed that HG reduced the mRNA level for vacuolar H(+)-ATPase, but did not alter those of chloride channel-5 and Na(+)-H(+)-exchanger-3. In conclusion, the chronic HG inhibits albumin reabsorption by lysosomal alkalinization in PTECs, probably due to ATP depletion and down-regulation of vacuolar H(+)-ATPase.

  14. Crocin Protects Podocytes Against Oxidative Stress and Inflammation Induced by High Glucose Through Inhibition of NF-κB

    Directory of Open Access Journals (Sweden)

    Sutong Li

    2017-07-01

    Full Text Available Background/Aims: Diabetic nephropathy (DN is a microangiopathic disease characterized by excessive urinary albumin excretion, which occurs in 30% of patients with diabetes mellitus. It is the second leading cause of end-stage renal diseases in China. Nuclear factor-kappa B (NF-κB is reported to be closely correlated with the inflammation underlying diabetes-associated renal damage. Crocin, a plant-derived compound, has antioxidant properties that may inhibit NF-κB. Methods: In the present study, we used a conditionally immortalized mouse podocyte cell line to explore whether crocin could effectively block albuminuria. Cells were incubated with 15 or 25 mM D-glucose to mimic diabetic conditions. The expression of Wilms tumor 1 (WT-1 and synaptopodin was evaluated to identify differentiated podocytes, and the expression of nephrin, podocin, and CD2ap was measured as markers of slit diaphragms, the main structures within the glomerular filtration barrier. Results: The high-glucose conditions led to reduced nephrin, podocin, and CD2ap expression, which was prevented by pretreatment with crocin. The oxidative stress and pro-inflammatory response of podocytes associated with DN induced by high glucose were also reduced by crocin pretreatment. Phosphorylated IκBα (p-IκBα expression induced by high glucose was also significantly decreased by crocin pretreatment. Moreover, pyrrolidine dithiocarbamate, a NF-κB inhibitor, pyrrolidine dithio carbamate, augmented the protective effects of crocin. Conclusion: Our results demonstrate a protective role of crocin against damage to podocytes and slit diaphragms under high-glucose conditions via inhibition of NF-κB. This study presents a potential therapy for DN and contributes to the understanding of the mechanism underlying DN.

  15. High Glucose-Mediated STAT3 Activation in Endometrial Cancer Is Inhibited by Metformin: Therapeutic Implications for Endometrial Cancer

    Science.gov (United States)

    Wallbillich, John J.; Josyula, Srirama; Saini, Uksha; Zingarelli, Roman A.; Dorayappan, Kalpana Deepa Priya; Riley, Maria K.; Wanner, Ross A.; Cohn, David E.; Selvendiran, Karuppaiyah

    2017-01-01

    Objectives STAT3 is over-expressed in endometrial cancer, and diabetes is a risk factor for the development of type 1 endometrial cancer. We therefore investigated whether glucose concentrations influence STAT3 expression in type 1 endometrial cancer, and whether such STAT3 expression might be inhibited by metformin. Methods In Ishikawa (grade 1) endometrial cancer cells subjected to media with low, normal, or high concentrations of glucose, expression of STAT3 and its target proteins was evaluated by real-time quantitative PCR (qPCR). Ishikawa cells were treated with metformin and assessed with cell proliferation, survival, migration, and ubiquitin assays, as well as Western blot and qPCR. Expression of apoptosis proteins was evaluated with Western blot in Ishikawa cells transfected with a STAT3 overexpression plasmid and treated with metformin. A xenograft tumor model was used for studying the in vivo efficacy of metformin. Results Expression of STAT3 and its target proteins was increased in Ishikawa cells cultured in high glucose media. In vitro, metformin inhibited cell proliferation, survival and migration but induced apoptosis. Metformin reduced expression levels of pSTAT3 ser727, total STAT3, and its associated cell survival and anti-apoptotic proteins. Additionally, metformin treatment was associated with increased degradation of pSTAT3 ser727. No change in apoptotic protein expression was noticed with STAT3 overexpression in Ishikawa cells. In vivo, metformin treatment led to a decrease in tumor weight as well as reductions of STAT3, pSTAT3 ser727, its target proteins. Conclusions These results suggest that STAT3 expression in type 1 endometrial cancer is stimulated by a high glucose environment and inhibited by metformin. PMID:28114390

  16. Hyperoside inhibits high-glucose-induced vascular inflammation in vitro and in vivo.

    Science.gov (United States)

    Ku, Sae-Kwang; Kwak, Soyoung; Kwon, O-Jun; Bae, Jong-Sup

    2014-10-01

    Hyperoside, an active compound from the genera of Hypericum and Crataegus, was reported to have antioxidant, antihyperglycemic, anticancer, anti-inflammatory, and anticoagulant activities. Vascular inflammatory process has been suggested to play a key role in initiation and progression of atherosclerosis, a major complication of diabetes mellitus. Thus, in this study, we attempted to determine whether hyperoside can suppress vascular inflammatory processes induced by high glucose (HG) in human umbilical vein endothelial cells (HUVECs) and mice. Data showed that HG induced markedly increased vascular permeability, monocyte adhesion, expressions of cell adhesion molecules (CAMs), formation of reactive oxygen species (ROS), and activation of nuclear factor (NF)-κB. Remarkably, all of the above-mentioned vascular inflammatory effects of HG were attenuated by pretreatment with hyperoside. Vascular inflammatory responses induced by HG are critical events underlying development of various diabetic complications; therefore, our results suggest that hyperoside may have significant therapeutic benefits against diabetic complications and atherosclerosis.

  17. Orientin inhibits high glucose-induced vascular inflammation in vitro and in vivo.

    Science.gov (United States)

    Ku, Sae-Kwang; Kwak, Soyoung; Bae, Jong-Sup

    2014-12-01

    Vascular inflammation plays a key role in the initiation and progression of atherosclerosis, a major complication of diabetes mellitus. Orientin, a C-glycosyl flavonoid, is known to have anxiolytic and antioxidative activity. In this study, we assessed whether orientin can suppress vascular inflammation induced by high glucose (HG) in human umbilical vein endothelial cells (HUVECs) and mice. Our data indicate that HG markedly increased vascular permeability, monocyte adhesion, the expression of cell adhesion molecules (CAMs), the formation of reactive oxygen species (ROS), and the activation of nuclear factor kappa B (NF-κB). Remarkably, the vascular inflammatory effects of HG were attenuated by pretreatment with orientin. Since vascular inflammation induced by HG is critical in the development of diabetic complications, our results suggest that orientin may have significant benefits in the treatment of diabetic complications and atherosclerosis.

  18. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical term for high blood glucose (blood sugar). High blood glucose happens when the body has too little insulin or when the body can't use insulin properly. What Causes Hyperglycemia? A number of things can cause hyperglycemia: ...

  19. High glucose inhibits ClC-2 chloride channels and attenuates cell migration of rat keratinocytes

    Directory of Open Access Journals (Sweden)

    Pan F

    2015-08-01

    Full Text Available Fuqiang Pan, Rui Guo, Wenguang Cheng, Linlin Chai, Wenping Wang, Chuan Cao, Shirong LiDepartment of Plastic and Reconstructive Surgery, Southwestern Hospital, Third Military Medical University, Chongqing, People’s Republic of China Background: Accumulating evidence has demonstrated that migration of keratinocytes is critical to wound epithelialization, and defects of this function result in chronic delayed-healing wounds in diabetes mellitus patients, and the migration has been proved to be associated with volume-activated chloride channels. The aim of the study is to investigate the effects of high glucose (HG, 25 mM on ClC-2 chloride channels and cell migration of keratinocytes.Methods: Newborn Sprague Dawley rats were used to isolate and culture the keratinocyte in this study. Immunofluorescence assay, real-time polymerase chain reaction, and Western blot assay were used to examine the expression of ClC-2 protein or mRNA. Scratch wound assay was used to measure the migratory ability of keratinocytes. Transwell cell migration assay was used to measure the invasion and migration of keratinocytes. Recombinant lentivirus vectors were established and transducted to keratinocytes. Whole-cell patch clamp was used to perform the electrophysiological studies.Results: We found that the expression of ClC-2 was significantly inhibited when keratinocytes were exposed to a HG (25 mM medium, accompanied by the decline of volume-activated Cl- current (ICl,vol, migration potential, and phosphorylated PI3K as compared to control group. When knockdown of ClC-2 by RNAi or pretreatment with wortmannin, similar results were observed, including ICl,vol and migration keratinocytes were inhibited.Conclusion: Our study proved that HG inhibited ClC-2 chloride channels and attenuated cell migration of rat keratinocytes via inhibiting PI3K signaling.Keywords: high glucose, keratinocytes, ClC-2, cell migration, PI3K

  20. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day ... DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing ...

  1. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day ... DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing ...

  2. Brazilin Ameliorates High Glucose-Induced Vascular Inflammation via Inhibiting ROS and CAMs Production in Human Umbilical Vein Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Thanasekaran Jayakumar

    2014-01-01

    Full Text Available Vascular inflammatory process has been suggested to play a key role in the initiation and progression of atherosclerosis, a major complication of diabetes mellitus. Recent studies have shown that brazilin exhibits antihepatotoxic, antiplatelet, cancer preventive, or anti-inflammatory properties. Thus, we investigated whether brazilin suppresses vascular inflammatory process induced by high glucose (HG in cultured human umbilical vein endothelial cells (HUVEC. HG induced nitrite production, lipid peroxidation, and intracellular reactive oxygen species formation in HUVEC cells, which was reversed by brazilin. Western blot analysis revealed that brazilin markedly inhibited HG-induced phosphorylation of endothelial nitric oxide synthase. Besides, we investigated the effects of brazilin on the MAPK signal transduction pathway because MAPK families are associated with vascular inflammation under stress. Brazilin blocked HG-induced phosphorylation of extracellular signal-regulated kinase and transcription factor NF-κB. Furthermore, brazilin concentration-dependently attenuated cell adhesion molecules (ICAM-1 and VCAM-1 expression induced by various concentrations of HG in HUVEC. Taken together, the present data suggested that brazilin could suppress high glucose-induced vascular inflammatory process, which may be closely related with the inhibition of oxidative stress, CAMs expression, and NF-κB activation in HUVEC. Our findings may highlight a new therapeutic intervention for the prevention of vascular diseases.

  3. Emodin attenuates high glucose-induced TGF-β1 and fibronectin expression in mesangial cells through inhibition of NF-κB pathway

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Jie [Department of Pharmacology, School of Pharmacy, Guangxi Medical University, Nanning, Guangxi (China); Zeng, Zhi [Department of Physiology, School of Basic Courses, Guangdong Pharmaceutical University, Guangzhou, Guangdong (China); Wu, Teng [Vascular Biology Research Institute, Guangdong Pharmaceutical University, Guangzhou (China); Yang, Zhicheng [Department of Pharmacology, School of Pharmaceutical Science, Guangdong Pharmaceutical University, Guangzhou, Guangdong (China); Liu, Bing, E-mail: liubing52000@163.com [Department of Pharmacology, School of Pharmaceutical Science, Guangdong Pharmaceutical University, Guangzhou, Guangdong (China); Lan, Tian, E-mail: lantiansci@yahoo.com [Vascular Biology Research Institute, Guangdong Pharmaceutical University, Guangzhou (China)

    2013-12-10

    The activation of nuclear factor-κB (NF-κB) and the subsequent overexpression of its downstream targets transforming growth factor-β1 (TGF-β1) and fibronectin (FN) are among the hallmarks for the progressive diabetic nephropathy. Our previous studies demonstrated that emodin ameliorated renal injury and inhibited extracellular matrix accumulation in kidney and mesangial cells under diabetic condition. However, the molecular mechanism has not been fully elucidated. Here, we showed that emodin significantly attenuated high glucose-induced NF-κB nuclear translocation in mesangial cells. Interestingly, emodin also inhibited the DNA-binding activity and transcriptional activity of NF-κB. Furthermore, NF-κB-mediated TGF-β1 and FN expression was significantly decreased by emodin. These results demonstrated that emodin suppressed TGF-β1 and FN overexpression through inhibition of NF-κB activation, suggesting that emodin-mediated inhibition of the NF-κB pathway could protect against diabetic nephropathy. - Highlights: • Emodin decreased high glucose-induced p65 phosphorylation in MCs. • Emodin decreased high glucose-induced IκB-α degradation in MCs. • Emodin decreased high glucose-induced p65 translocation in MCs. • Emodin blocked high glucose-induced NF-κB activity. • Emodin blocked high glucose-induced the expression of TGF-β1 and FN.

  4. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor ... Islanders American Indian/Alaska Native Programs Older Adults Family Link Diabetes EXPO Upcoming Diabetes EXPOs EXPO Volunteer ...

  5. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day Diabetes Basics Home Symptoms Diagnosis America's Diabetes Challenge Type ...

  6. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor ... Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & Type 1 Diabetes Get Started Safely Get And ...

  7. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To ... Complications Neuropathy Foot Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & ...

  8. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor ... Options for the Uninsured Medicare Medicaid & CHIP For Parents & Kids Safe at School Everyday Life Children and ...

  9. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose ... Clinical Practice Guidelines Patient Education Materials Scientific Sessions Journals for Professionals Professional Books Patient Access to Research ...

  10. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To ... Index Low-Calorie Sweeteners Sugar and Desserts Fitness Exercise & Type 1 Diabetes Get Started Safely Get And ...

  11. Hydrogen sulfide inhibits high glucose-induced matrix protein synthesis by activating AMP-activated protein kinase in renal epithelial cells.

    Science.gov (United States)

    Lee, Hak Joo; Mariappan, Meenalakshmi M; Feliers, Denis; Cavaglieri, Rita C; Sataranatarajan, Kavithalakshmi; Abboud, Hanna E; Choudhury, Goutam Ghosh; Kasinath, Balakuntalam S

    2012-02-10

    Hydrogen sulfide, a signaling gas, affects several cell functions. We hypothesized that hydrogen sulfide modulates high glucose (30 mm) stimulation of matrix protein synthesis in glomerular epithelial cells. High glucose stimulation of global protein synthesis, cellular hypertrophy, and matrix laminin and type IV collagen content was inhibited by sodium hydrosulfide (NaHS), an H(2)S donor. High glucose activation of mammalian target of rapamycin (mTOR) complex 1 (mTORC1), shown by phosphorylation of p70S6 kinase and 4E-BP1, was inhibited by NaHS. High glucose stimulated mTORC1 to promote key events in the initiation and elongation phases of mRNA translation: binding of eIF4A to eIF4G, reduction in PDCD4 expression and inhibition of its binding to eIF4A, eEF2 kinase phosphorylation, and dephosphorylation of eEF2; these events were inhibited by NaHS. The role of AMP-activated protein kinase (AMPK), an inhibitor of protein synthesis, was examined. NaHS dose-dependently stimulated AMPK phosphorylation and restored AMPK phosphorylation reduced by high glucose. Compound C, an AMPK inhibitor, abolished NaHS modulation of high glucose effect on events in mRNA translation as well as global and matrix protein synthesis. NaHS induction of AMPK phosphorylation was inhibited by siRNA for calmodulin kinase kinase β, but not LKB1, upstream kinases for AMPK; STO-609, a calmodulin kinase kinase β inhibitor, had the same effect. Renal cortical content of cystathionine β-synthase and cystathionine γ-lyase, hydrogen sulfide-generating enzymes, was significantly reduced in mice with type 1 diabetes or type 2 diabetes, coinciding with renal hypertrophy and matrix accumulation. Hydrogen sulfide is a newly identified modulator of protein synthesis in the kidney, and reduction in its generation may contribute to kidney injury in diabetes.

  12. MiR-17 Downregulation by High Glucose Stabilizes Thioredoxin-Interacting Protein and Removes Thioredoxin Inhibition on ASK1 Leading to Apoptosis.

    Science.gov (United States)

    Dong, Daoyin; Fu, Noah; Yang, Peixin

    2016-03-01

    Pregestational diabetes significantly increases the risk of neural tube defects (NTDs). Maternal diabetes activates an Apoptosis Signal-regulating Kinase 1 (ASK1)-initiated pathway, which triggers neural stem cell apoptosis of the developing neuroepithelium leading to NTD formation. How high glucose of diabetes activates ASK1 is still unclear. In this study, we investigated the mechanism underlying high glucose-induced ASK1 activation. High glucose suppressed miR-17 expression, which led to an increase in its target gene Txnip (Thioredoxin-interacting protein). High glucose-increased Txnip enhanced its binding to the ASK1 inhibitor, thioredoxin (Trx), and thereby sequestered Trx from the Trx-ASK1 complex. High glucose-induced ASK1 activation and consequent apoptosis were abrogated by either the miR-17 mimic or Txnip siRNA knockdown. In contrast, the miR-17 inhibitor or Txnip ectopic overexpression mimicked the stimulative effect of high glucose on ASK1 and apoptosis. Thus, our study demonstrated that miR-17 repression mediates the pro-apoptotic effect of high glucose, and revealed a new mechanism underlying ASK1 activation, in which decreased miR-17 removes Trx inhibition on ASK1 through Txnip. © The Author 2015. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

  13. Ginkgolide B Suppresses TLR4-Mediated Inflammatory Response by Inhibiting the Phosphorylation of JAK2/STAT3 and p38 MAPK in High Glucose-Treated HUVECs

    Directory of Open Access Journals (Sweden)

    Kun Chen

    2017-01-01

    Full Text Available Aim. Ginkgolide B is a Ginkgo biloba leaf extract that has been identified as a natural platelet-activating factor receptor (PAFR antagonist. We investigated the effect of ginkgolide B on high glucose-induced TLR4 activation in human umbilical vein endothelial cells (HUVECs. Methods. Protein expression was analyzed by immunoblotting. Small-interfering RNA (siRNA was used to knock down PAFR and TLR4 expression. Results. Ginkgolide B suppressed the expression of TLR4 and MyD88 that was induced by high glucose. Ginkgolide B also reduced the levels of platelet endothelial cell adhesion molecule-1, interleukin-6, and monocyte chemotactic protein 1. Further, we examined the association between PAFR and TLR4 by coimmunoprecipitation. The result showed that high glucose treatment caused the binding of PAFR and TLR4, whereas ginkgolide B abolished this binding. The functional analysis indicated that PAFR siRNA treatment reduced TLR4 expression, and TLR4 siRNA treatment decreased PAFR expression in high glucose-treated HUVECs, further supporting the coimmunoprecipitation data. Ginkgolide B inhibited the phosphorylation of Janus kinase 2 (JAK2/signal transducer and activator of transcription 3 (STAT3 and p38 mitogen-activated protein kinase (MAPK. Conclusion. Ginkgolide B exerted protective effects by inhibiting the TLR4-mediated inflammatory response in high glucose-treated endothelial cells. The mechanism of action of ginkgolide B might be associated with inhibition of the JAK2/STAT3 and p38 MAPK phosphorylation.

  14. 1,25(OH)2D3 inhibits the deleterious effects induced by high glucose on osteoblasts through undercarboxylated osteocalcin and insulin signaling.

    Science.gov (United States)

    Wu, Ying-ying; Yu, Tao; Zhang, Xiao-hui; Liu, Yan-shan; Li, Feng; Wang, Yan-ying; Wang, Yong-yue; Gong, Ping

    2012-10-01

    Diabetes mellitus (DM) is associated with multiple skeletal disorders, and vitamin D may play a functional role in the preservation of glucose tolerance. However, the relationship between vitamin D deficiency and DM is not well known. The aim of this study was to investigate the potential molecular link between 1,25(OH)(2)D(3) regulation and glucose homeostasis. Rat primary osteoblasts were cultured in different conditioned medium: normal glucose, high glucose, high glucose and insulin, high glucose and 1,25(OH)(2)D(3), high glucose and insulin and 1,25(OH)(2)D(3). The activity of osteoblasts was measured by cell viability, alkaline phosphatase and osteocalcin assay. The potential mechanism of how 1,25(OH)(2)D(3) affect insulin sensitivity was investigated by the assay of insulin receptor (IR) and vitamin D receptor (VDR) expression, and undercarboxylated osteocalcin (ucOC) level. The combined treatment has the strongest effect of inhibiting the deleterious effects induced by high glucose on osteoblasts, and it promoted the %ucOC value to approximately 40%, which is much higher than that in high glucose without treatment. Levels of IR and VDR of osteoblasts in combined treatment culture increased significantly compared with that in high glucose without treatment. So maybe 1,25(OH)(2)D(3) promotes insulin sensitivity of osteoblasts by activating insulin signaling and simultaneously stimulating ucOC secretion, which in turn regulate insulin production and sensitivity. 1,25(OH)(2)D(3) might be beneficial not only for diabetes, but also, for osteoporosis by promoting bone formation.

  15. Pyridoxine and pyridoxamine inhibits superoxide radicals and prevents lipid peroxidation, protein glycosylation, and (Na+ + K+)-ATPase activity reduction in high glucose-treated human erythrocytes.

    Science.gov (United States)

    Jain, S K; Lim, G

    2001-02-01

    Vitamin B(6) (pyridoxine) supplementation has been found beneficial in preventing diabetic neuropathy and retinopathy, and the glycosylation of proteins. Oxygen radicals and oxidative damage have been implicated in the cellular dysfunction and complications of diabetes. This study was undertaken to test the hypothesis that pyridoxine (P) and pyridoxamine (PM) inhibit superoxide radical production, reduce lipid peroxidation and glycosylation, and increase the (Na+ + K+)-ATPase activity in high glucose-exposed red blood cells (RBC). Superoxide radical production was assessed by the reduction of cytochrome C by glucose in the presence and absence of P or PM in a cell-free buffered solution. To examine cellular effects, washed normal human RBC were treated with control and high glucose concentrations with and without P or PM. Both P and PM significantly lowered lipid peroxidation and glycated hemoglobin (HbA(1)) formation in high glucose-exposed RBC. P and PM significantly prevented the reduction in (Na+ + K+)-ATPase activity in high glucose-treated RBC. Thus, P or PM can inhibit oxygen radical production, which in turn prevents the lipid peroxidation, protein glycosylation, and (Na+ + K+)-ATPase activity reduction induced by the hyperglycemia. This study describes a new biochemical mechanism by which P or PM supplementation may delay or inhibit the development of complications in diabetes.

  16. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... an Employer Options for the Uninsured Medicare Medicaid & CHIP For Parents & Kids Safe at School Everyday Life ... blood sugar). High blood glucose happens when the body has too little insulin or when the body ...

  17. Aspalathin and Nothofagin from Rooibos (Aspalathus linearis) inhibits high glucose-induced inflammation in vitro and in vivo.

    Science.gov (United States)

    Ku, Sae-Kwang; Kwak, Soyoung; Kim, Yaesol; Bae, Jong-Sup

    2015-02-01

    Vascular inflammation plays a key role in the initiation and progression of atherosclerosis, a major complication of diabetes mellitus. Aspalathin (Asp) and nothofagin (Not) are two major active dihydrochalcones found in green rooibos, which have been reported for their antioxidant activity. In this study, we assessed whether Asp or Not can suppress vascular inflammation induced by high glucose (HG) in human umbilical vein endothelial cells (HUVECs) and mice. We monitored the effects of Asp or Not on HG-induced vascular hyperpermeability, expression of cell adhesion molecules (CAMs), formation of reactive oxygen species (ROS), and activation of nuclear factor (NF)-κB in vitro and in vivo. Our data indicate that HG markedly increased vascular permeability, monocyte adhesion, expression of CAMs, formation of ROS, and activation of NF-κB. Remarkably, treatment of Asp or Not inhibited HG-mediated vascular hyperpermeability, adhesion of monocytes toward HUVECs, and expression of CAMs. In addition, Asp or Not suppressed the formation of ROS and the activation of NF-κB. Since vascular inflammation induced by HG is critical in the development of diabetic complications, our results suggest that Asp or Not may have significant benefits in the treatment of diabetic complications.

  18. Propolis, a Constituent of Honey, Inhibits the Development of Sugar Cataracts and High-Glucose-Induced Reactive Oxygen Species in Rat Lenses

    Directory of Open Access Journals (Sweden)

    Teppei Shibata

    2016-01-01

    Full Text Available Purpose. This study investigated the effects of oral propolis on the progression of galactose-induced sugar cataracts in rats and the in vitro effects of propolis on high-glucose-induced reactive oxygen species (ROS and cell death in cultured rat lens cells (RLECs. Methods. Galactose-fed rats and RLECs cultured in high glucose (55 mM medium were treated with propolis or vehicle control. Relative lens opacity was assessed by densitometry and changes in lens morphology by histochemical analysis. Intracellular ROS levels and cell viability were measured. Results. Oral administration of propolis significantly inhibited the onset and progression of cataract in 15% and 25% of galactose-fed rats, respectively. RLECs cultured with high glucose showed a significant increase in ROS expression with reduced cell viability. Treatment of these RLECs with 5 and 50 μg/mL propolis cultured significantly reduced ROS levels and increased cell viability, indicating that the antioxidant activity of propolis protected cells against ROS-induced damage. Conclusion. Propolis significantly inhibited the onset and progression of sugar cataract in rats and mitigated high-glucose-induced ROS production and cell death. These effects may be associated with the ability of propolis to inhibit hyperglycemia-evoked oxidative or osmotic stress-induced cellular insults.

  19. Propolis, a Constituent of Honey, Inhibits the Development of Sugar Cataracts and High-Glucose-Induced Reactive Oxygen Species in Rat Lenses

    Science.gov (United States)

    Shibata, Teppei; Shibata, Shinsuke; Shibata, Naoko; Kiyokawa, Etsuko; Singh, Dhirendra P.

    2016-01-01

    Purpose. This study investigated the effects of oral propolis on the progression of galactose-induced sugar cataracts in rats and the in vitro effects of propolis on high-glucose-induced reactive oxygen species (ROS) and cell death in cultured rat lens cells (RLECs). Methods. Galactose-fed rats and RLECs cultured in high glucose (55 mM) medium were treated with propolis or vehicle control. Relative lens opacity was assessed by densitometry and changes in lens morphology by histochemical analysis. Intracellular ROS levels and cell viability were measured. Results. Oral administration of propolis significantly inhibited the onset and progression of cataract in 15% and 25% of galactose-fed rats, respectively. RLECs cultured with high glucose showed a significant increase in ROS expression with reduced cell viability. Treatment of these RLECs with 5 and 50 μg/mL propolis cultured significantly reduced ROS levels and increased cell viability, indicating that the antioxidant activity of propolis protected cells against ROS-induced damage. Conclusion. Propolis significantly inhibited the onset and progression of sugar cataract in rats and mitigated high-glucose-induced ROS production and cell death. These effects may be associated with the ability of propolis to inhibit hyperglycemia-evoked oxidative or osmotic stress-induced cellular insults. PMID:27242920

  20. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Eating Overweight Smoking High Blood Pressure Physical Activity High Blood Glucose My Health Advisor Tools To Know Your Risk Alert Day Diabetes Basics Home Symptoms Diagnosis America's Diabetes Challenge Type 1 Type 2 Facts About Type 2 Enroll in ...

  1. Agmatine protects Müller cells from high-concentration glucose-induced cell damage via N-methyl-D-aspartic acid receptor inhibition.

    Science.gov (United States)

    Han, Ning; Yu, Li; Song, Zhidu; Luo, Lifu; Wu, Yazhen

    2015-07-01

    Neural injury is associated with the development of diabetic retinopathy. Müller cells provide structural and metabolic support for retinal neurons. High glucose concentrations are known to induce Müller cell activity. Agmatine is an endogenous polyamine, which is enzymatically formed in the mammalian brain and has exhibited neuroprotective effects in a number of experimental models. The aims of the present study were to investigate whether agmatine protects Müller cells from glucose-induced damage and to explore the mechanisms underlying this process. Lactate dehydrogenase activity and tumor necrosis factor-α mRNA expression were significantly reduced in Müller cells exposed to a high glucose concentration, following agmatine treatment, compared with cells not treated with agmatine. In addition, agmatine treatment inhibited glucose-induced Müller cell apoptosis, which was associated with the regulation of Bax and Bcl-2 expression. Agmatine treatment suppressed glucose-induced phosphorylation of mitogen-activated protein kinase (MAPK) protein in Müller cells. The present study demonstrated that the protective effects of agmatine on Müller cells were inhibited by N-methyl-D-aspartic acid (NMDA). The results of the present study suggested that agmatine treatment protects Müller cells from high-concentration glucose-induced cell damage. The underlying mechanisms may relate to the anti-inflammatory and antiapoptotic effects of agmatine, as well as to the inhibition of the MAPK pathway, via NMDA receptor suppression. Agmatine may be of use in the development of novel therapeutic approaches for patients with diabetic retinopathy.

  2. Sodium tanshinone IIA silate inhibits high glucose-induced vascular smooth muscle cell proliferation and migration through activation of AMP-activated protein kinase.

    Directory of Open Access Journals (Sweden)

    Wen-yu Wu

    Full Text Available The proliferation of vascular smooth muscle cells may perform a crucial role in the pathogenesis of diabetic vascular disease. AMPK additionally exerts several salutary effects on vascular function and improves vascular abnormalities. The current study sought to determine whether sodium tanshinone IIA silate (STS has an inhibitory effect on vascular smooth muscle cell (VSMC proliferation and migration under high glucose conditions mimicking diabetes without dyslipidemia, and establish the underlying mechanism. In this study, STS promoted the phosphorylation of AMP-activated protein kinase (AMPK at T172 in VSMCs. VSMC proliferation was enhanced under high glucose (25 mM glucose, HG versus normal glucose conditions (5.5 mM glucose, NG, and this increase was inhibited significantly by STS treatment. We utilized western blotting analysis to evaluate the effects of STS on cell-cycle regulatory proteins and found that STS increased the expression of p53 and the Cdk inhibitor, p21, subsequent decreased the expression of cell cycle-associated protein, cyclin D1. We further observed that STS arrested cell cycle progression at the G0/G1 phase. Additionally, expression and enzymatic activity of MMP-2, translocation of NF-κB, as well as VSMC migration were suppressed in the presence of STS. Notably, Compound C (CC, a specific inhibitor of AMPK, as well as AMPK siRNA blocked STS-mediated inhibition of VSMC proliferation and migration. We further evaluated its potential for activating AMPK in aortas in animal models of type 2 diabetes and found that Oral administration of STS for 10 days resulted in activation of AMPK in aortas from ob/ob or db/db mice. In conclusion, STS inhibits high glucose-induced VSMC proliferation and migration, possibly through AMPK activation. The growth suppression effect may be attributable to activation of AMPK-p53-p21 signaling, and the inhibitory effect on migration to the AMPK/NF-κB signaling axis.

  3. High-glucose inhibits human fibroblast cell migration in wound healing via repression of bFGF-regulating JNK phosphorylation.

    Directory of Open Access Journals (Sweden)

    Yuan Hu Xuan

    Full Text Available One of the major symptoms of diabetes mellitus (DM is delayed wound healing, which affects large populations of patients worldwide. However, the underlying mechanism behind this illness remains elusive. Skin wound healing requires a series of coordinated processes, including fibroblast cell proliferation and migration. Here, we simulate DM by application of high glucose (HG in human foreskin primary fibroblast cells to analyze the molecular mechanism of DM effects on wound healing. The results indicate that HG, at a concentration of 30 mM, delay cell migration, but not cell proliferation. bFGF is known to promote cell migration that partially rescues HG effects on cell migration. Molecular and cell biology studies demonstrated that HG enhanced ROS production and repressed JNK phosphorylation, but did not affect Rac1 activity. JNK and Rac1 activation were known to be important for bFGF regulated cell migration. To further confirm DM effects on skin repair, a type 1 diabetic rat model was established, and we observed the efficacy of bFGF on both normal and diabetic rat skin repair. Furthermore, proteomic studies identified an increase of Annexin A2 protein nitration in HG-stressed fibroblasts and the nitration was protected by activation of bFGF signaling. Treatment with FGFR1 and JNK inhibitors delayed cell migration and increased Annexin A2 nitration levels, indicating that Annexin A2 nitration is modulated by bFGF signaling via activation of JNK. Together with these results, our data suggests that the HG-mediated delay of cell migration is linked to the inhibition of bFGF signaling, specifically through JNK suppression.

  4. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... In Memory In Honor Become a Member En Español Type 1 Type 2 About Us Online Community ... Page Text Size: A A A Listen En Español Hyperglycemia (High Blood Glucose) Hyperglycemia is the technical ...

  5. Aldose reductase inhibition counteracts nitrosative stress and poly(ADP-ribose) polymerase activation in diabetic rat kidney and high-glucose-exposed human mesangial cells

    OpenAIRE

    Drel, Viktor R.; Pacher, Pal; Stevens, Martin J; Obrosova, Irina G.

    2006-01-01

    Both increased aldose reductase (AR) activity and oxidative/nitrosative stress have been implicated in the pathogenesis of diabetic nephropathy, but the relation between the two factors remains a subject of debate. This study evaluated the effects of AR inhibition on nitrosative stress and poly(ADP-ribose) polymerase (PARP) activation in diabetic rat kidney and high-glucose-exposed human mesangial cells. In animal experiments, control (C) and streptozotocin-diabetic (D) rats were treated with...

  6. Fluvastatin inhibits activation of JAK and STAT proteins in diabetic rat glomeruli and mesangial cells under high glucose conditions

    Institute of Scientific and Technical Information of China (English)

    Yong-hong SHI; Song ZHAO; Chen WANG; Ying LI; Hui-jun DUAN

    2007-01-01

    Aim: The aim of the present study was to further elucidate the mechanism of the protective role of fluvastatin on diabetic nephropathy. Methods: Streptozotocin- induced diabetic rats were treated daily with fluvastatin (4 mg/kg body weight) by gavage. The animals were killed 4 weeks later and urine and blood samples were collected. The kidney tissues were removed and subjected to the following experiments. Rat glomerular mesangial cells (GMC) were cultured under normal glucose (5.5 mmol/L), high glucose (HG, 30 mmol/L), HG+AG490 (10 μmol/L), or HG with fluvastatin (1 pmol/L). Glomeruli or the GMC lysate was immunoprecipi- tated and/or immunoblotted with antibodies against Janus kinase 2 (JAK2), SH2- domain containing tyrosine phosphatase-1 (SHP-1), phosphospecific SHP-2, and signal transducer and activators of transcription (STAT), respectively. Trans- forming growth factor-β (TGF-β) mRNA was measured by RT-PCR. The protein synthesis of TGF-β1 and fibronectin in the culture medium of GMC was detected by ELISA. Results: The phosphorylation levels of JAK2, STAT1, STAT3, and SHP-2 increased significantly, and SHP-1 phosphorylation was reduced in glom- eruli of diabetic rats. Treatment with fluvastatin reduced phosphorylation levels of JAK2, STAT1, STAT3, and SHP-2 in glomeruli of diabetic rats, but it had no effect on the dephosphorylation of SHP-1. The exposure of GMC to 30 mmol/L glucose caused the activation of JAK2, STAT1, STAT3, and SHP-2. It upregulated TGF-β1 expression and increased protein synthesis of fibronectin. These high glucose-induced changes were suppressed by fluvastatin, as well as AG490, a JAK2 inhibitor. Conclusion: The regulation of the phosphorylation of JAK/STAT by fluvastatin may be responsible for its renal protective effects on diabetic nephropathy.

  7. Aldose reductase inhibition counteracts nitrosative stress and poly(ADP-ribose) polymerase activation in diabetic rat kidney and high-glucose-exposed human mesangial cells.

    Science.gov (United States)

    Drel, Viktor R; Pacher, Pal; Stevens, Martin J; Obrosova, Irina G

    2006-04-15

    Both increased aldose reductase (AR) activity and oxidative/nitrosative stress have been implicated in the pathogenesis of diabetic nephropathy, but the relation between the two factors remains a subject of debate. This study evaluated the effects of AR inhibition on nitrosative stress and poly(ADP-ribose) polymerase (PARP) activation in diabetic rat kidney and high-glucose-exposed human mesangial cells. In animal experiments, control (C) and streptozotocin-diabetic (D) rats were treated with/without the AR inhibitor fidarestat (F, 16 mg kg(-1) day(-1)) for 6 weeks starting from induction of diabetes. Glucose, sorbitol, and fructose concentrations were significantly increased in the renal cortex of D vs C (p diabetes-induced increase in kidney weight as well as nitrotyrosine (NT, a marker of peroxynitrite-induced injury and nitrosative stress), and poly(ADP-ribose) (a marker of PARP activation) accumulation, assessed by both immunohistochemistry and Western blot analysis, in glomerular and tubular compartments of the renal cortex. In vitro studies revealed the presence of both AR and PARP-1 in human mesangial cells, and none of these two variables were affected by high glucose or F treatment. Nitrosylated and poly(ADP-ribosyl)ated proteins (Western blot analysis) accumulated in cells cultured in 30 mM D-glucose (vs 5.55 mM glucose, p diabetic renal cortex and high-glucose-exposed human mesangial cells. These findings reveal new beneficial properties of the AR inhibitor F and provide the rationale for detailed studies of F on diabetic nephropathy.

  8. AMP-activated protein kinase inhibits TGF-β-, angiotensin II-, aldosterone-, high glucose-, and albumin-induced epithelial-mesenchymal transition.

    Science.gov (United States)

    Lee, Jang Han; Kim, Ji Hyun; Kim, Ja Seon; Chang, Jai Won; Kim, Soon Bae; Park, Jung Sik; Lee, Sang Koo

    2013-03-15

    The epithelial-mesenchymal transition (EMT) is a novel mechanism that promotes renal fibrosis. Transforming growth factor-β (TGF-β), angiotensin II, aldosterone, high glucose, and urinary albumin are well-known causes of EMT and renal fibrosis. We examined whether and how activation of AMP-activated protein kinase (AMPK) suppressed EMT induced by the above agents in tubular epithelial cells. All experiments were performed using HK-2 cells. Protein expression was measured by Western blot analysis. Intracellular reactive oxygen species (ROS) were analyzed by flow cytometry. Exposure of tubular cells to TGF-β (10 ng/ml), angiotensin II (1 μM), aldosterone (100 nM), high glucose (30 mM), and albumin (5 mg/ml) for 5 days induced EMT, as shown by upregulation of α-smooth muscle actin and downregulation of E-cadherin. ROS and NADPH oxidase 4 (Nox4) expression were increased, and antioxidants such as tiron and N-acetylcysteine inhibited EMT induction. Metformin (the best known clinical activator of AMPK) suppressed EMT induction through inhibition of ROS via induction of heme oxygenase-1 and endogenous antioxidant thioredoxin. An AMPK inhibitor (compound C) and AMPK small interfering RNA blocked the effect of metformin, and another AMPK activator [5-aminoimidazole-4-carboxamide-1β riboside (AICAR)] exerted the same effects as metformin. In conclusion, AMPK activation might be beneficial in attenuating the tubulointerstitial fibrosis induced by TGF-β, angiotensin II, aldosterone, high glucose, and urinary albumin.

  9. Paeonol Inhibits Proliferation of Vascular Smooth Muscle Cells Stimulated by High Glucose via Ras-Raf-ERK1/2 Signaling Pathway in Coculture Model

    Directory of Open Access Journals (Sweden)

    Junjun Chen

    2014-01-01

    Full Text Available Paeonol (Pae has been previously reported to protect against atherosclerosis (AS by inhibiting vascular smooth muscle cell (VSMC proliferation or vascular endothelial cell (VEC injury. But studies lack how VSMCs and VECs interact when Pae plays a role. The current study was based on a coculture model of VSMCs and VECs to investigate the protective mechanisms of Pae on atherosclerosis (AS by determining the secretory function of VECs and proliferation of VSMCs focusing on the Ras-Raf-ERK1/2 signaling pathway. VECs were stimulated by high glucose. Our data showed that high concentration (35.5 mM of glucose induced damage in VECs. Injury of VECs stimulated VSMC proliferation in the coculture model. Pae (120 μM decreased vascular endothelial growth factor (VEGF and platelet derivative growth factor B (PDGF-B release from VECs and inhibited overexpression of Ras, P-Raf, and P-ERK proteins in VSMCs. The results indicate that diabetes modulates the inflammatory response in VECs to stimulate VSMC proliferation and promote the development of AS. Pae was beneficial by inhibiting the inflammatory effects of VECs on VSMC proliferation. This study suggests the inhibitory mechanism of Pae due to the inhibition of VEGF and PDGF-B secretion in VECs and Ras-Raf-ERK1/2 signaling pathway in VSMCs.

  10. DANGER is involved in high glucose-induced radioresistance through inhibiting DAPK-mediated anoikis in non-small cell lung cancer.

    Science.gov (United States)

    Kwon, TaeWoo; Youn, HyeSook; Son, Beomseok; Kim, Daehoon; Seong, Ki Moon; Park, Sungkyun; Kim, Wanyeon; Youn, BuHyun

    2016-02-09

    18F-labeled fluorodeoxyglucose (FDG) uptake during FDG positron emission tomography seems to reflect increased radioresistance. However, the exact molecular mechanism underlying high glucose (HG)-induced radioresistance is unclear. In the current study, we showed that ionizing radiation-induced activation of the MEK-ERK-DAPK-p53 signaling axis is required for anoikis (anchorage-dependent apoptosis) of non-small cell lung cancer (NSCLC) cells in normal glucose media. Phosphorylation of DAPK at Ser734 by ERK was essential for p53 transcriptional activity and radiosensitization. In HG media, overexpressed DANGER directly bound to the death domain of DAPK, thus inhibiting the catalytic activity of DAPK. In addition, inhibition of the DAPK-p53 signaling axis by DANGER promoted anoikis-resistance and epithelial-mesenchymal transition (EMT), resulting in radioresistance of HG-treated NSCLC cells. Notably, knockdown of DANGER enhanced anoikis, EMT inhibition, and radiosensitization in a mouse xenograft model of lung cancer. Taken together, our findings offered evidence that overexpression of DANGER and the subsequent inhibitory effect on DAPK kinase activity are critical responses that account for HG-induced radioresistance of NSCLC.

  11. Hydrogen Sulfide Inhibits High Glucose-Induced sFlt-1 Production via Decreasing ADAM17 Expression in 3T3-L1 Adipocytes

    Directory of Open Access Journals (Sweden)

    Tian-xiao Hu

    2017-01-01

    Full Text Available Hydrogen sulfide (H2S has recently been identified as an endogenous gaseous signaling molecule. The aim of the present study was to investigate the effect of H2S on high glucose- (HG- induced ADAM17 expression and sFlt-1 production in 3T3-L1 adipocytes. Firstly, we found that HG DMEM upregulated the expression of ADAM17 and production of sFlt-1 in 3T3-L1 adipocytes. Knocking down ADAM17 attenuated the effect of high glucose on sFlt-1 production in adipocytes. HG decreased the expression of CSE and 3-MST, as well as the endogenous H2S production. Furthermore, knocking down CSE and 3-MST significantly increased ADAM17 expression and sFlt-1 production. The addition of exogenous H2S through the administration of sodium hydrosulfide (NaHS inhibited HG-induced upregulation of ADAM17 expression and sFlt-1 production. In conclusion, decreased expression of CSE and 3-MST and the subsequent decrease in H2S production contribute to high glucose-induced sFlt-1 production via activating ADAM17 in adipocytes. Exogenous H2S donor NaHS has a potential therapeutic value for diabetic vascular complications.

  12. Resveratrol inhibits high glucose induced collagen upregulation in cardiac fibroblasts through regulating TGF-β1-Smad3 signaling pathway.

    Science.gov (United States)

    Liu, Junhui; Zhuo, Xiaozhen; Liu, Weimin; Wan, Zhaofei; Liang, Xiao; Gao, Shanshan; Yuan, Zuyi; Wu, Yue

    2015-02-05

    Cardiac fibrosis is a common pathological process presented in a variety of diseases, including hypertension and diabetes. Cardiac fibroblasts (CFs) have been identified as the most important participants in the development of cardiac fibrosis. Exposure of cultured CFs to high glucose (HG) or angiotensin II (Ang II) resulted in increased collagen synthesis. Resveratrol (Res) is a natural polyphenol exhibiting anti-fibrosis effects in a number of different organs fibrosis process, whether Res can prevent HG and Ang II induced fibrosis response in CFs remains unclear. The aim of this work was to evaluate the effects of Res in HG and Ang II induced fibrosis response in CFs. We cultured rat CFs in either normal glucose (5.6 mM) or HG (25 mM) media in the presence of Res or not and the changes in collagens synthesis and TGF-β1 production were assessed by Real-time PCR, Western blotting, and enzyme linked immunosorbent assay (ELISA). Furthermore, normal and diabetic mice (induced by single dose of streptozotocin (100 mg/kg) via tail vein) receiving Res (10 mg/kg) were used to explore the effects of Res on cardiac fibrosis in vivo. Masson staining and immunohistochemistry were performed to visualize cardiac collagen deposition. Results indicate that CFs exposed to HG condition shows enhanced proliferation rate. Furthermore, in the presence of HG or Ang II, CFs exhibited increased collagens synthesis and TGF-β1 production. And these effects were abolished by Res intervention. In vivo results show that diabetic mice exhibit increased collagen deposition in the cardiac compared with the normal mice. And this change was prevented by the treatment of Res. These results suggest that Res possesses a potential antifibrogenic effect in hypertension and diabetes-related cardiac fibrosis. Moreover, the action mechanism is probably associated with its ability to reduce TGF-β1 content in CFs.

  13. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... events, such as eating breakfast, take on exaggerated importance. It's a world where a person needs a ... Living With Diabetes Treatment and Care Blood Glucose Testing Checking Your Blood Glucose A1C and eAG Hypoglycemia ( ...

  14. A novel chalcone derivative attenuates the diabetes-induced renal injury via inhibition of high glucose-mediated inflammatory response and macrophage infiltration

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Qilu [Chemical Biology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Zhao, Leping [Department of Pharmacy, the Affiliated Yueqing Hospital, Wenzhou Medical University, Wenzhou, Zhejiang (China); Wang, Yi; Zhang, Yali [Chemical Biology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Li, Zhaoyu [Department of International High School, Shanghai Jiaotong University Nanyang Affiliated (Kunshan) School, Minhang District, Shanghai (China); Pan, Yong; Kanchana, Karvannan; Wang, Jingying; Tong, Chao [Chemical Biology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China); Li, Dan, E-mail: yqyyld@163.com [Department of Nephrology, the Affiliated Yueqing Hospital, Wenzhou Medical University, Wenzhou, Zhejiang (China); Liang, Guang, E-mail: wzmcliangguang@163.com [Chemical Biology Research Center, School of Pharmaceutical Sciences, Wenzhou Medical University, Wenzhou, Zhejiang (China)

    2015-01-15

    Inflammation plays a central role in the development and progression of diabetic nephropathy (DN). Researches on novel anti-inflammatory agents may offer new opportunities for the treatment of DN. We previously found a chalcone derivative L6H21 could inhibit LPS-induced cytokine release from macrophages. The aim of this study was to investigate whether L6H21 could ameliorate the high glucose-mediated inflammation in NRK-52E cells and attenuate the inflammation-mediated renal injury. According to the results, L6H21 showed a great inhibitory effect on the expression of pro-inflammatory cytokines, cell adhesion molecules, chemokines, and macrophage adhesion via down-regulation of NF-κB/MAPKs activity in high glucose-stimulated renal NRK-52E cells. Further, in vivo oral administration with L6H21 at a dosage of 20 mg/kg/2 days showed a decreased expression of pro-inflammatory cytokines, cell adhesion molecules, which subsequently contributed to the inhibition on renal macrophage infiltration, the reduction of serum creatinine and BUN levels, and the improvement on the fibrosis and pathological changes in the renal tissues of diabetic mice. These findings provided that chalcone derived L6H21 may be a promising anti-inflammatory agent and have the potential in the therapy of diabetic nephropathy, and importantly, MAPK/NF-κB signaling system may be a novel therapeutic target for human DN in the future. - Highlights: • Inflammation plays a central role in the development of diabetic nephropathy. • Compound L6H21 reduced the high glucose-mediated inflammation in NRK-52E cells. • Compound L6H21 attenuated the inflammation-mediated renal injury. • L6H21 exhibited anti-inflammatory effects via inactivation of NF-κB/MAPKs. • MAPKs/NF-κB may be a novel therapeutic target in diabetic nephropathy treatment.

  15. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... the urine Frequent urination Increased thirst Part of managing your diabetes is checking your blood glucose often. ... how to handle this condition. Medical IDs Many people with diabetes, particularly those who use insulin, should ...

  16. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... the urine Frequent urination Increased thirst Part of managing your diabetes is checking your blood glucose often. ... Type 2 Diabetes Program Food & Fitness Food Recipes Planning Meals What Can I Eat Weight Loss Fitness ...

  17. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Us in the Fight for a Cure Your tax-deductible gift today can fund critical diabetes research ... glucose for fuel, so your body breaks down fats to use for energy. When your body breaks ...

  18. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy 8 Tips for Caregivers ... updated, this is the "take-you-by-the-hand" guide that will become a trusted friend and ...

  19. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... the urine Frequent urination Increased thirst Part of managing your diabetes is checking your blood glucose often. ... also help. Work with your dietitian to make changes in your meal plan. If exercise and changes ...

  20. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... the urine Frequent urination Increased thirst Part of managing your diabetes is checking your blood glucose often. ... Sleeve Custom jerseys for your Tour de Cure team benefits the cause. Ask the Experts: Learn to ...

  1. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin ... Diabetes Pro: Professional Resources Online We Support Your Doctor Clinical Practice Guidelines Patient Education Materials Scientific Sessions ...

  2. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy ...

  3. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More ... us get closer to curing diabetes and better treatments for those living with diabetes. Other Ways to ...

  4. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More ... us get closer to curing diabetes and better treatments for those living with diabetes. Other Ways to ...

  5. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy 8 Tips for Caregivers Health Insurance Health ... glucose happens when the body has too little insulin or when the body can't use insulin ...

  6. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Step On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C ... your doctor may change the amount of your medication or insulin or possibly the timing of when ...

  7. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... blood glucose early will help you avoid problems associated with hyperglycemia. How Do I Treat Hyperglycemia? You ... Advocacy Take Action Advocacy Priorities News & Events The Cost of Diabetes Advocate Toolkit Call to Congress Research & ...

  8. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... work with your doctor to find the safest way for you to lower your blood glucose level. Cutting down on the amount of food you eat might also help. Work with your dietitian to make changes in your meal plan. If exercise and changes ...

  9. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... glucose) Dawn Phenomenon Checking for Ketones Tight Diabetes Control donate en -- Support a Cure - 2017-05-donation- ... well with diabetes. Shopdiabetes.org: Your Stress-Free System for Family Dinners! - 2017-03-book-oclock-scramble. ...

  10. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Neuropathy Foot Complications DKA (Ketoacidosis) & Ketones Kidney Disease (Nephropathy) Gastroparesis Mental Health Step On Up Treatment & Care Blood Glucose Testing Medication Doctors, Nurses & More Oral Health & Hygiene Women A1C Insulin Pregnancy 8 Tips for Caregivers Health Insurance Health Insurance ...

  11. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... and Care > Blood Glucose Testing Share: Print Page Text Size: A A A Listen En Español Hyperglycemia ( ... Advocacy Take Action Advocacy Priorities News & Events The Cost of Diabetes Advocate ... Resources Shop Diabetes » Close nonprofit software

  12. 1,25(OH)2D3 inhibits high glucose-induced apoptosis and ROS production in human peritoneal mesothelial cells via the MAPK/P38 pathway.

    Science.gov (United States)

    Yang, Lina; Wu, Lan; Du, Shuyan; Hu, Ye; Fan, Yi; Ma, Jianfei

    2016-07-01

    The regulation of cell proliferation, differentiation and immunomodulation are affected by 1,25(OH)2D3. However, its function during apoptosis and oxidative stress in human peritoneal mesothelial cells (HPMCs) remains unknown. The aim of the present study was to investigate whether the regulation of apoptosis and oxidative stress have therapeutic relevance in peritoneal dialysis (PD) therapy. The present study investigated the effects of 1,25(OH)2D3 on high glucose (HG)-induced apoptosis and reactive oxygen species (ROS) production in HPMCs, and examined the underlying molecular mechanisms. Flow cytometry and western blotting were performed to detect cell apoptosis, 2,7-dichlorofluorescein diacetate was used to measure reactive oxygen species production and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide was used to measure cell viability. The results of the present study demonstrated that exposure to HG increased apoptosis and ROS production in HPMCs, whereas pretreatment with 1,25(OH)2D3 significantly inhibited HG‑induced apoptosis and ROS production. Further analysis revealed that 1,25(OH)2D3 facilitated cell survival via the MAPK/P38 pathway. The results of the present study indicate that 1,25(OH)2D3 inhibits apoptosis and ROS production in HG‑induced HPMCs via inhibition of the MAPK/P38 pathway.

  13. Inhibition of SGLT2 alleviates diabetic nephropathy by suppressing high glucose-induced oxidative stress in type 1 diabetic mice.

    Science.gov (United States)

    Hatanaka, Takashi; Ogawa, Daisuke; Tachibana, Hiromi; Eguchi, Jun; Inoue, Tatsuyuki; Yamada, Hiroshi; Takei, Kohji; Makino, Hirofumi; Wada, Jun

    2016-08-01

    It is unclear whether the improvement in diabetic nephropathy by sodium glucose cotransporter 2 (SGLT2) inhibitors is caused by a direct effect on SGLT2 or by the improvement in hyperglycemia. Here, we investigated the effect of dapagliflozin on early-stage diabetic nephropathy using a mouse model of type 1 diabetes and murine proximal tubular epithelial cells. Eight-week-old Akita mice were treated with dapagliflozin or insulin for 12 weeks. Body weight, urinary albumin excretion, blood pressure, as well as levels of blood glucose and hemoglobin A1c were measured. Expansion of the mesangial matrix, interstitial fibrosis, and macrophage infiltration in kidneys were evaluated by histology. Oxidative stress and apoptosis were evaluated in kidneys and cultured proximal tubular epithelial cells. Compared with nontreated mice, dapagliflozin and insulin decreased blood glucose and hemoglobin A1c levels equally. Urine volume and water intake increased significantly in the dapagliflozin-treated group compared with those in the insulin-treated group, but there were no differences in body weight or blood pressure between the two groups. Macrophage infiltration and fibrosis in renal interstitium improved significantly in the dapagliflozin group compared with the insulin group. Oxidative stress was attenuated by dapagliflozin, and suppression occurred in a dose-dependent manner. RNAi knockdown of SGLT2 resulted in reduced oxidative stress. Dapagliflozin ameliorates diabetic nephropathy by suppressing hyperglycemia-induced oxidative stress in a manner independent of hyperglycemia improvement in Akita mice. Our findings suggest that dapagliflozin may be a novel therapeutic approach for the treatment of diabetic nephropathy.

  14. Inhibition of the canonical Wnt pathway by high glucose can be reversed by parathyroid hormone-related protein in osteoblastic cells.

    Science.gov (United States)

    López-Herradón, Ana; Portal-Núñez, Sergio; García-Martín, Adela; Lozano, Daniel; Pérez-Martínez, Francisco C; Ceña, Valentín; Esbrit, Pedro

    2013-08-01

    Recent in vivo findings suggest that the bone sparing effect of parathyroid hormone-related protein (PTHrP) in diabetic mice might occur at least in part through targeting a suppressed Wnt/β-catenin pathway in osteoblasts. We here aimed to examine the inhibitory action of a high glucose environment on specific components of the canonical Wnt pathway, and the putative compensatory effects of PTHrP, in osteoblastic cell cultures. Mouse osteoblastic MC3T3-E1 cells and primary cultures of fetal mouse calvaria were exposed to normal (5.5 mM) or high (25 mM) D-glucose (HG), with or without PTHrP (1-36) or PTHrP (107-139) for different times. In some experiments, MC3T3-E1 cells were incubated with the Wnt pathway activators Wnt3a and LiCl, or were transfected with plasmids encoding either a mutated β-catenin that cannot be targeted for degradation or a human PTHrP (-36/+139) cDNA, or the corresponding empty plasmid, in the presence or absence of HG. The gene expression of Wnt3a and low density receptor-like proteins (LRP)-5 and 6, as well as β-catenin protein stabilization and β-catenin-dependent transcription activity were evaluated. Oxidative stress status under HG condition was also assessed. The present data demonstrate that HG can target different components of the canonical Wnt pathway, while β-catenin degradation appears to be a key event leading to inhibition of Wnt/β-catenin signaling in mouse osteoblastic cells. Both PTHrP peptides tested were able to counteract this deleterious action of HG. These in vitro findings also provide new clues to understand the underlying mechanisms whereby PTHrP can increase bone formation. Copyright © 2013 Wiley Periodicals, Inc.

  15. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... 2 Diabetes Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High ... What Can I Drink? Fruit Dairy Food Tips Eating Out Quick Meal Ideas Snacks Nutrient Content Claims ...

  16. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... Type 2 Diabetes Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity High ... Holiday Meal Planning What Can I Eat? Making Healthy Food Choices Diabetes ... Tips Eating Out Quick Meal Ideas Snacks Nutrient Content Claims ...

  17. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... to Give Close Are You at Risk? Home Prevention Diagnosing Diabetes and Learning About Prediabetes Type 2 Diabetes Risk Test Lower Your Risk Healthy Eating Overweight Smoking High Blood Pressure Physical Activity ...

  18. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... and Learning About Prediabetes Type 2 Diabetes Risk Test Lower Your Risk Healthy Eating Overweight Smoking High ... excused. 86 million Americans have prediabetes. Take the test. Know where you stand. sticky en -- Chef Ronaldo's ...

  19. Hyperglycemia (High Blood Glucose)

    Medline Plus

    Full Text Available ... and Learning About Prediabetes Type 2 Diabetes Risk Test Lower Your Risk Healthy Eating Overweight Smoking High ... You at Risk? Diagnosis Lower Your Risk Risk Test Alert Day Prediabetes My Health Advisor Tools to ...

  20. High glucose-induced mitochondrial respiration and reactive oxygen species in mouse cerebral pericytes is reversed by pharmacological inhibition of mitochondrial carbonic anhydrases: Implications for cerebral microvascular disease in diabetes.

    Science.gov (United States)

    Shah, Gul N; Morofuji, Yoichi; Banks, William A; Price, Tulin O

    2013-10-18

    Hyperglycemia-induced oxidative stress leads to diabetes-associated damage to the microvasculature of the brain. Pericytes in close proximity to endothelial cells in the brain microvessels are vital to the integrity of the blood-brain barrier and are especially susceptible to oxidative stress. According to our recently published results, streptozotocin-diabetic mouse brain exhibits oxidative stress and loose pericytes by twelve weeks of diabetes, and cerebral pericytes cultured in high glucose media suffer intracellular oxidative stress and apoptosis. Oxidative stress in diabetes is hypothesized to be caused by reactive oxygen species (ROS) produced during hyperglycemia-induced enhanced oxidative metabolism of glucose (respiration). To test this hypothesis, we investigated the effect of high glucose on respiration rate and ROS production in mouse cerebral pericytes. Previously, we showed that pharmacological inhibition of mitochondrial carbonic anhydrases protects the brain from oxidative stress and pericyte loss. The high glucose-induced intracellular oxidative stress and apoptosis of pericytes in culture were also reversed by inhibition of mitochondrial carbonic anhydrases. Therefore, we extended our current study to determine the effect of these inhibitors on high glucose-induced increases in pericyte respiration and ROS. We now report that both the respiration and ROS are significantly increased in pericytes challenged with high glucose. Furthermore, inhibition of mitochondrial carbonic anhydrases significantly slowed down both the rate of respiration and ROS production. These data provide new evidence that pharmacological inhibitors of mitochondrial carbonic anhydrases, already in clinical use, may prove beneficial in protecting the brain from oxidative stress caused by ROS produced as a consequence of hyperglycemia-induced enhanced respiration. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. AtRH57, a DEAD-box RNA helicase, is involved in feedback inhibition of glucose-mediated abscisic acid accumulation during seedling development and additively affects pre-ribosomal RNA processing with high glucose.

    Science.gov (United States)

    Hsu, Yi-Feng; Chen, Yun-Chu; Hsiao, Yu-Chun; Wang, Bing-Jyun; Lin, Shih-Yun; Cheng, Wan-Hsing; Jauh, Guang-Yuh; Harada, John J; Wang, Co-Shine

    2014-01-01

    The Arabidopsis thaliana T-DNA insertion mutant rh57-1 exhibited hypersensitivity to glucose (Glc) and abscisic acid (ABA). The other two rh57 mutants also showed Glc hypersensitivity similar to rh57-1, strongly suggesting that the Glc-hypersensitive feature of these mutants results from mutation of AtRH57. rh57-1 and rh57-3 displayed severely impaired seedling growth when grown in Glc concentrations higher than 3%. The gene, AtRH57 (At3g09720), was expressed in all Arabidopsis organs and its transcript was significantly induced by ABA, high Glc and salt. The new AtRH57 belongs to class II DEAD-box RNA helicase gene family. Transient expression of AtRH57-EGFP (enhanced green fluorescent protein) in onion cells indicated that AtRH57 was localized in the nucleus and nucleolus. Purified AtRH57-His protein was shown to unwind double-stranded RNA independent of ATP in vitro. The ABA biosynthesis inhibitor fluridone profoundly redeemed seedling growth arrest mediated by sugar. rh57-1 showed increased ABA levels when exposed to high Glc. Quantitative real time polymerase chain reaction analysis showed that AtRH57 acts in a signaling network downstream of HXK1. A feedback inhibition of ABA accumulation mediated by AtRH57 exists within the sugar-mediated ABA signaling. AtRH57 mutation and high Glc conditions additively caused a severe defect in small ribosomal subunit formation. The accumulation of abnormal pre-rRNA and resistance to protein synthesis-related antibiotics were observed in rh57 mutants and in the wild-type Col-0 under high Glc conditions. These results suggested that AtRH57 plays an important role in rRNA biogenesis in Arabidopsis and participates in response to sugar involving Glc- and ABA signaling during germination and seedling growth.

  2. High glucose impairs superoxide production from isolated blood neutrophils

    DEFF Research Database (Denmark)

    Perner, A; Nielsen, S E; Rask-Madsen, J

    2003-01-01

    Superoxide (O(2)(-)), a key antimicrobial agent in phagocytes, is produced by the activity of NADPH oxidase. High glucose concentrations may, however, impair the production of O(2)(-) through inhibition of glucose-6-phosphate dehydrogenase (G6PD), which catalyzes the formation of NADPH. This stud...... measured the acute effects of high glucose or the G6PD inhibitor dehydroepiandrosterone (DHEA) on the production of O(2)(-) from isolated human neutrophils....

  3. High glucose impairs superoxide production from isolated blood neutrophils

    DEFF Research Database (Denmark)

    Perner, A; Nielsen, S E; Rask-Madsen, J

    2003-01-01

    Superoxide (O(2)(-)), a key antimicrobial agent in phagocytes, is produced by the activity of NADPH oxidase. High glucose concentrations may, however, impair the production of O(2)(-) through inhibition of glucose-6-phosphate dehydrogenase (G6PD), which catalyzes the formation of NADPH. This study...

  4. Icariin attenuates high glucose-induced type IV collagen and fibronectin accumulation in glomerular mesangial cells by inhibiting transforming growth factor-β production and signalling through G protein-coupled oestrogen receptor 1.

    Science.gov (United States)

    Li, Yi-Chen; Ding, Xuan-Sheng; Li, Hui-Mei; Zhang, Cheng

    2013-09-01

    Icariin has been shown to attenuate diabetic nephropathy in rats by decreasing transforming growth factor-β (TGF-β) and type IV collagen expression, but its mode of action in glomerular mesangial cells is uncertain. The present study aimed to investigate the effect of icariin on excess mesangial type IV collagen and fibronectin accumulation induced by high glucose, and to determine the mechanism underlying its protective effects. Under high-glucose conditions, icariin diminished type IV collagen and fibronectin accumulation, as well as TGF-β production in human and rat mesangial cells. Mesangial cells treated with icariin after TGF-β1 exposure expressed less type IV collagen and fibronectin than those without icariin treatment, suggesting inhibition by icariin of TGF-β1 downstream pathways. On TGF-β1 stimulation, icariin inhibited TGF-β canonical Smad signalling and extracellular signal-regulated kinase (ERK)1/2 signalling by decreasing Smad2/3 and ERK1/2 phosphorylation in a dose-dependent manner. U0126, which blocked the ERK1/2 pathway, exerted an additive effect on the icariin suppression of type IV collagen and fibronectin expression, enhancing the beneficial effects of icariin. The G protein-coupled oestrogen receptor 1 (GPER) antagonist, G-15, abolished the icariin-induced inhibition of type IV collagen, and fibronectin overproduction and TGF-β signalling. Treatment of cells with fulvestrant, a downregulator of the oestrogen receptor, enhanced the action of icariin. In conclusion, icariin decreased type IV collagen and fibronectin accumulation induced by high glucose in mesangial cells by inhibiting TGF-β production, as well as Smad and ERK signalling in a GPER-dependent manner.

  5. Berberine improves glucose metabolism in diabetic rats by inhibition of hepatic gluconeogenesis.

    Directory of Open Access Journals (Sweden)

    Xuan Xia

    Full Text Available Berberine (BBR is a compound originally identified in a Chinese herbal medicine Huanglian (Coptis chinensis French. It improves glucose metabolism in type 2 diabetic patients. The mechanisms involve in activation of adenosine monophosphate activated protein kinase (AMPK and improvement of insulin sensitivity. However, it is not clear if BBR reduces blood glucose through other mechanism. In this study, we addressed this issue by examining liver response to BBR in diabetic rats, in which hyperglycemia was induced in Sprague-Dawley rats by high fat diet. We observed that BBR decreased fasting glucose significantly. Gluconeogenic genes, Phosphoenolpyruvate carboxykinase (PEPCK and Glucose-6-phosphatase (G6Pase, were decreased in liver by BBR. Hepatic steatosis was also reduced by BBR and expression of fatty acid synthase (FAS was inhibited in liver. Activities of transcription factors including Forkhead transcription factor O1 (FoxO1, sterol regulatory element-binding protein 1c (SREBP1 and carbohydrate responsive element-binding protein (ChREBP were decreased. Insulin signaling pathway was not altered in the liver. In cultured hepatocytes, BBR inhibited oxygen consumption and reduced intracellular adenosine triphosphate (ATP level. The data suggest that BBR improves fasting blood glucose by direct inhibition of gluconeogenesis in liver. This activity is not dependent on insulin action. The gluconeogenic inhibition is likely a result of mitochondria inhibition by BBR. The observation supports that BBR improves glucose metabolism through an insulin-independent pathway.

  6. Glucose feedback inhibition of amylase activity in Aspergillus sp. and release of this inhibition when cocultured with Saccharomyces cerevisiae

    Energy Technology Data Exchange (ETDEWEB)

    Reddy, C.A.; Abouzied, M.M.

    1986-11-01

    The effect of starch and glucose concentration on amylase activity by Aspergillus niger, A. foetidus and A. awamori was determined. Up to 15 U/ml of amylase activity was observed in extracellular fluid of cultures grown with 1-2% starch for 7 days; however, no amylase activity was detectable in the extracellular fluid of otherwise identical cultures grown with 3-5% starch, even though these cultures contained substantial concentrations of glucose (16-20 mg/ml) which could only have been derived from starch hydrolysis. When extracellular fluid from the 5% starch cultures was dialysed to remove soluble sugar, high level of amylase activity was observed. Addition of increasing amounts of glucose to the dialysed extracellular fluid resulted in increasing levels of inhibition of amylase activity. Coculture of the Aspergillus species with Saccharomyces cerevisiae, an efficient sugar fermenting yeast, in 5% starch medium resulted in low sugar concentration and high amylase activity (greater than 18 U/ml) in the extracellular fluid. Amylase activity in cultures grown with glucose was comparable to that observed in cultures grown with glucose plus starch or starch only. These results lead us to conclude that amylase activity in the Aspergillus species studied is subject to feed back inhibition by glucose but is not subject to catabolite repression by glucose or starch as previously believed. Furthermore, the amylase activity in these organisms appears to be inducible by starch. 22 references.

  7. High glucose-mediated oxidative stress impairs cell migration.

    Directory of Open Access Journals (Sweden)

    Marcelo L Lamers

    Full Text Available Deficient wound healing in diabetic patients is very frequent, but the cellular and molecular causes are poorly defined. In this study, we evaluate the hypothesis that high glucose concentrations inhibit cell migration. Using CHO.K1 cells, NIH-3T3 fibroblasts, mouse embryonic fibroblasts and primary skin fibroblasts from control and diabetic rats cultured in 5 mM D-glucose (low glucose, LG, 25 mM D-glucose (high glucose, HG or 25 mM L-glucose medium (osmotic control--OC, we analyzed the migration speed, protrusion stability, cell polarity, adhesion maturation and the activity of the small Rho GTPase Rac1. We also analyzed the effects of reactive oxygen species by incubating cells with the antioxidant N-Acetyl-Cysteine (NAC. We observed that HG conditions inhibited cell migration when compared to LG or OC. This inhibition resulted from impaired cell polarity, protrusion destabilization and inhibition of adhesion maturation. Conversely, Rac1 activity, which promotes protrusion and blocks adhesion maturation, was increased in HG conditions, thus providing a mechanistic basis for the HG phenotype. Most of the HG effects were partially or completely rescued by treatment with NAC. These findings demonstrate that HG impairs cell migration due to an increase in oxidative stress that causes polarity loss, deficient adhesion and protrusion. These alterations arise, in large part, from increased Rac1 activity and may contribute to the poor wound healing observed in diabetic patients.

  8. Lactobacillus sakei OK67 ameliorates high-fat diet-induced blood glucose intolerance and obesity in mice by inhibiting gut microbiota lipopolysaccharide production and inducing colon tight junction protein expression.

    Science.gov (United States)

    Lim, Su-Min; Jeong, Jin-Ju; Woo, Kyung Hee; Han, Myung Joo; Kim, Dong-Hyun

    2016-04-01

    A high-fat diet (HFD) induces obesity and the associated increases in blood glucose and inflammation through changes in gut microbiota, endotoxemia, and increased gut permeability. To counteract this, researchers have suggested that the use of probiotics that suppress production of proinflammatory lipopolysaccharide (LPS). Here, we tested whether Lactobacillus sakei OK67, which inhibits gut microbiota LPS production selected from among the lactic acid bacteria isolated from kimchi, exerted antihypoglycemic or anti-inflammatory effects in HFD-fed mice. Mice were randomly divided into 2 groups and fed an HFD or a low-fat diet for 4 weeks. These groups were further subdivided; 1 subgroup was treated with L sakei OK67 and fed the experimental diet for 4.5 weeks, whereas the other subgroup was fed the experimental diet alone. L sakei OK67 treatment lowered HFD-elevated LPS levels in blood and colonic fluid and significantly decreased HFD-elevated fasting blood glucose levels and the area under the curve in an oral glucose tolerance test. L sakei OK67 treatment inhibited HFD-induced body and epididymal fat weight gains, suppressed HFD-induced tumor necrosis factor-α and interleukin-1β expression and nuclear factor-κB activation in the colon, and significantly increased HFD-suppressed interleukin-10 and tight junction protein expression in the colon. Oral administration of L sakei OK67 significantly downregulated HFD-induced expression of peroxisome proliferator-activated receptor γ, fatty acid synthase, and tumor necrosis factor-α in adipose tissue. In addition, L sakei OK67 treatment strongly inhibited nuclear factor-κB activation in LPS-stimulated peritoneal macrophages. We report that L sakei OK67 ameliorates HFD-induced hyperglycemia and obesity by reducing inflammation and increasing the expression of colon tight junction proteins in mice.

  9. Sesquiterpene Lactones and Their Derivatives Inhibit High Glucose-Induced NF-κB Activation and MCP-1 and TGF-β1 Expression in Rat Mesangial Cells

    Directory of Open Access Journals (Sweden)

    Hai-Bo Long

    2013-10-01

    Full Text Available Diabetic nephropathy (DN is one of the most common and serious chronic complications of diabetes mellitus, however, no efficient clinical drugs exist for the treatment of DN. We selected and synthesized several sesquiterpene lactones (SLs, and then used the MTT assay to detect rat mesangial cells (MCs proliferation, ELISA to measure the expression level of monocyte chemoattractant protein-1 (MCP-1, transforming growth factor beta (TGF-β1 and fibronectin(FN, real-time fluorescent quantitative PCR analysis to measure the MCP-1 and TGF-β1 gene expression, western blot to detect the level of IκBα protein and EMSA to measure the activation of nuclear factor kappa B (NF-κB. We discovered that SLs, including parthenolide (PTL, micheliolide (MCL, arglabin, and isoalantolactone (IAL, as well as several synthetic analogs of these molecules, could effectively attenuate the high glucose-stimulated activation of NF-κB, the degradation of IκBα, and the expression of MCP-1, TGF-β1 and FN in rat mesangial cells (MCs. These findings suggest that SLs and their derivatives have potential as candidate drugs for the treatment of DN.

  10. Effect and Modeling of Glucose Inhibition and In Situ Glucose Removal During Enzymatic Hydrolysis of Pretreated Wheat Straw

    DEFF Research Database (Denmark)

    Andric, Pavle; Meyer, Anne S.; Jensen, Peter Arendt

    2010-01-01

    , during 96 h of reaction. When glucose was removed by dialysis during the enzymatic hydrolysis, the cellulose conversion rates and glucose yields increased. In fact, with dialytic in situ glucose removal, the rate of enzyme-catalyzed glucose release during 48-72 h of reaction recovered from 20......-40% to become approximate to 70% of the rate recorded during 6-24 h of reaction. Although Michaelis-Menten kinetics do not suffice to model the kinetics of the complex multi-enzymatic degradation of cellulose, the data for the glucose inhibition were surprisingly well described by simple Michaelis......-Menten inhibition models without great significance of the inhibition mechanism. Moreover, the experimental in situ removal of glucose could be simulated by a Michaelis-Menten inhibition model. The data provide an important base for design of novel reactors and operating regimes which include continuous product...

  11. Why Do SGLT2 Inhibitors Inhibit Only 30–50% of Renal Glucose Reabsorption in Humans?

    OpenAIRE

    Liu, Jiwen; Lee, TaeWeon; DeFronzo, Ralph A.

    2012-01-01

    Sodium glucose cotransporter 2 (SGLT2) inhibition is a novel and promising treatment for diabetes under late-stage clinical development. It generally is accepted that SGLT2 mediates 90% of renal glucose reabsorption. However, SGLT2 inhibitors in clinical development inhibit only 30–50% of the filtered glucose load. Why are they unable to inhibit 90% of glucose reabsorption in humans? We will try to provide an explanation to this puzzle in this perspective analysis of the unique pharmacokineti...

  12. Renal glucose handling in diabetes and sodium glucose cotransporter 2 inhibition

    Directory of Open Access Journals (Sweden)

    Resham Raj Poudel

    2013-01-01

    Full Text Available The kidneys play a major role in glucose homeostasis through its utilization, gluconeogenesis, and reabsorption via sodium glucose cotransporters (SGLTs. The defective renal glucose handling from upregulation of SGLTs, mainly the SGLT2, plays a fundamental role in the pathogenesis of type 2 diabetes mellitus. Genetic mutations in a SGLT2 isoform that results in benign renal glycosuria, as well as clinical studies with SGLT2 inhibitors in type 2 diabetes support the potential of this approach. These studies indicate that inducing glycosuria by suppressing SGLT2 can reduce plasma glucose and A1c levels, as well as decrease weight, resulting in improved β-cell function and enhanced insulin sensitivity in liver and muscle. Because the mechanism of SGLT2 inhibition is independent of insulin secretion and sensitivity, these agents can be combined with other antidiabetic agents, including exogenous insulin. This class represents a novel therapeutic approach with potential for the treatment of both type 2 and type 1 diabetes.

  13. Sodium glucose transporter 2 (SGLT2 inhibition and ketogenesis

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2015-01-01

    Full Text Available Sodium glucose transporter 2 (SGLT2 inhibitors are a recently developed class of drug that have been approved for use in type 2 diabetes. Their unique extra-pancreatic glucuretic mode of action has encouraged their usage in type 1 diabetes as well. At the same time, reports of pseudo ketoacidosis and ketoacidosis related to their use have been published. No clear mechanism for this phenomenon has been demonstrated so far. This communication delves into the biochemical effects of SGLT2 inhibition, discusses the utility of these drugs and proposes steps to maximize safe usage of the molecules.

  14. Sodium glucose transporter 2 (SGLT2) inhibition and ketogenesis.

    Science.gov (United States)

    Kalra, Sanjay; Sahay, Rakesh; Gupta, Yashdeep

    2015-01-01

    Sodium glucose transporter 2 (SGLT2) inhibitors are a recently developed class of drug that have been approved for use in type 2 diabetes. Their unique extra-pancreatic glucuretic mode of action has encouraged their usage in type 1 diabetes as well. At the same time, reports of pseudo ketoacidosis and ketoacidosis related to their use have been published. No clear mechanism for this phenomenon has been demonstrated so far. This communication delves into the biochemical effects of SGLT2 inhibition, discusses the utility of these drugs and proposes steps to maximize safe usage of the molecules.

  15. Electroacupuncture regulates glucose-inhibited neurons in treatment of simple obesity

    Institute of Scientific and Technical Information of China (English)

    Zhi Yu; Youbing Xia; Chuanhui Ju; Qinghua Shao; Zhen Mao; Yun Gu; Bin Xu

    2013-01-01

    The glucose-inhibited neurons present in the lateral hypothalamic area are regarded as glucose detectors. This structure is involved in the regulation of food intake through extracellular blood glucose concentrations, and plays a crucial role in obesity onset. In the present study, obesity models established with high fat feeding were treated with electroacupuncture at Zusanli (ST36)/ Inner Court (ST44) on the left side and Tianshu (ST25) bilaterally. We found that electroacupuncture could effectively reduce body weight and the fat-weight ratio, and decrease serum leptin, resistin, tumor necrosis factor alpha, and neuropeptide Y levels, while increase serum adiponectin and cholecystokinin-8 levels. This treatment altered the electrical activity of glucose-inhibited neurons in the lateral hypothalamic area, with electroacupuncture at Zusanli/ Inner Court exerting an inhibitory effect, while electroacupuncture at bilateral Tianshu exerting an excitatory effect. These data suggest that electroacupuncture at the lower limbs and abdominal cavity is an effective means for regulating the activity of glucose-inhibited neurons in the lateral hypothalamic area and for improving the secretory function of adipose tissue.

  16. Converting enzyme inhibitor temocaprilat prevents high glucose-mediated suppression of human aortic endothelial cell proliferation.

    Science.gov (United States)

    Yasunari, Kenichi; Maeda, Kensaku; Watanabe, Takanori; Nakamura, Munehiro; Asada, Akira; Yoshikawa, Junichi

    2003-12-01

    We examined the involvement of the oxidative stress in high glucose-induced suppression of human aortic endothelial cell proliferation. Chronic glucose treatment for 72 h concentration-dependently (5.6-22.2 mol/l) inhibited human coronary endothelial cell proliferation. Temocaprilat, an angiotensin-converting enzyme inhibitor, at 10 nmol/l to 1 micromol/l inhibited high glucose (22.2 mmol/l)-mediated suppression of human aortic endothelial cell proliferation. Temocaprilat at 1 micromol/l inhibited high glucose-induced membrane-bound protein kinase C activity in human aortic endothelial cells. The protein kinase C inhibitors calphostin C 100 nmol/l or chelerythrine 1 micromol/l inhibited high glucose-mediated suppression of human aortic endothelial cell proliferation. Chronic high glucose treatment for 72 h increased intracellular oxidative stress, directly measured by flow cytometry using carboxydichlorofluorescein diacetate bis-acetoxymethyl ester, and this increase was significantly suppressed by temocaprilat 10 nmol/l to 1 micromol/l. Bradykinin B2 receptor antagonist icatibant 100 nmol/l significantly reduced the action of temocaprilat; whereas bradykinin B1 receptor antagonist des-Arg9-Leu8-bradykinin 100 nmol/l had no effect. These findings suggest that high glucose inhibits human aortic endothelial cell proliferation and that the angiotensin-converting enzyme inhibitor temocaprilat inhibits high glucose-mediated suppression of human aortic endothelial cell proliferation, possibly through suppression of protein kinase C, bradykinin B2 receptors and oxidative stress.

  17. Ergostatrien-3β-ol from Antrodia camphorata inhibits diabetes and hyperlipidemia in high-fat-diet treated mice via regulation of hepatic related genes, glucose transporter 4, and AMP-activated protein kinase phosphorylation.

    Science.gov (United States)

    Kuo, Yueh-Hsiung; Lin, Cheng-Hsiu; Shih, Chun-Ching

    2015-03-11

    This study was designed to explore the effects and mechanism of ergostatrien-3β-ol (EK100) from the submerged whole broth of Antrodia camphorata on diabetes and dyslipidemia in high fat diet (HFD)-fed mice for 12 weeks. The C57BL/6J mouse fed with a high fat diet (HFD) could induce insulin resistance and hyperlipidemia. After 8 week of induction, mice were receiving EK100 (at three dosages) or fenofibrate (Feno) or rosiglitazone (Rosi) or vehicle by oral gavage 4 weeks afterward. HFD-fed mice display increased blood glucose, glycated hemoglobin (HbA1c), total cholesterol (TC), triglyceride (TG), insulin, and leptin levels. These blood markers were significantly lower in EK100-treated mice, and finally ameliorated insulin resistance. EK100 treatment exhibited reduced hepatic ballooning degeneration and size of visceral adipocytes. Glucose transporter 4 (GLUT4) proteins and phosphorylation of Akt in skeletal muscle were significantly increased in EK100- and Rosi-treated mice. EK100, Feno, and Rosi treatment led to significant increases in phosphorylation of AMP-activated protein kinase (phospho-AMPK) protein in both skeletal muscle and liver. Moreover, EK100 caused a decrease in hepatic expressions of phosphenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6 Pase), and decreased glucose production. EK100 lowered blood TG level by inhibition of hepatic fatty acid synthesis by dampening sterol response element binding protein-1c (SREBP-1c) but increasing expression of peroxisome proliferator activated receptor α (PPARα). Moreover, EK100-treated mice reduced blood TC levels by decreased hepatic expressions of SREBP2, which plays a major role in the regulation of cholesterol synthesis. EK100 increased high-density lipoprotein cholesterol (HDL-C) concentrations by increasing expressions of apolipoprotein A-I (apo A-I) in liver tissue. Our findings manifest that EK100 may have therapeutic potential in treating type 2 diabetes associated with hyperlipidemia

  18. The glucose metabolite methylglyoxal inhibits expression of the glucose transporter genes by inactivating the cell surface glucose sensors Rgt2 and Snf3 in yeast.

    Science.gov (United States)

    Roy, Adhiraj; Hashmi, Salman; Li, Zerui; Dement, Angela D; Cho, Kyu Hong; Kim, Jeong-Ho

    2016-03-01

    Methylglyoxal (MG) is a cytotoxic by-product of glycolysis. MG has inhibitory effect on the growth of cells ranging from microorganisms to higher eukaryotes, but its molecular targets are largely unknown. The yeast cell-surface glucose sensors Rgt2 and Snf3 function as glucose receptors that sense extracellular glucose and generate a signal for induction of expression of genes encoding glucose transporters (HXTs). Here we provide evidence that these glucose sensors are primary targets of MG in yeast. MG inhibits the growth of glucose-fermenting yeast cells by inducing endocytosis and degradation of the glucose sensors. However, the glucose sensors with mutations at their putative ubiquitin-acceptor lysine residues are resistant to MG-induced degradation. These results suggest that the glucose sensors are inactivated through ubiquitin-mediated endocytosis and degraded in the presence of MG. In addition, the inhibitory effect of MG on the glucose sensors is greatly enhanced in cells lacking Glo1, a key component of the MG detoxification system. Thus the stability of these glucose sensors seems to be critically regulated by intracellular MG levels. Taken together, these findings suggest that MG attenuates glycolysis by promoting degradation of the cell-surface glucose sensors and thus identify MG as a potential glycolytic inhibitor.

  19. High glucose suppresses embryonic stem cell differentiation into neural lineage cells

    Science.gov (United States)

    Yang, Penghua; Shen, Wei-bin; Reece, E. Albert; Chen, Xi; Yang, Peixin

    2017-01-01

    Abnormal neurogenesis occurs during embryonic development in human diabetic pregnancies and in animal models of diabetic embryopathy. Our previous studies in a mouse model of diabetic embryopathy have implicated that high glucose of maternal diabetes delays neurogenesis in the developing neuroepithelium leading to neural tube defects. However, the underlying process in high glucose-impaired neurogenesis is uncharacterized. Neurogenesis from embryonic stem (ES) cells provides a valuable model for understanding the abnormal neural lineage development under high glucose conditions. ES cells are commonly generated and maintained in high glucose (approximately 25 mM glucose). Here, the mouse ES cell line, E14, was gradually adapted to and maintained in low glucose (5 mM), and became a glucose responsive E14 (GR-E14) line. High glucose induced the endoplasmic reticulum stress marker, CHOP, in GR-E14 cells. Under low glucose conditions, the GR-E14 cells retained their pluripotency and capability to differentiate into neural lineage cells. GR-E14 cell differentiation into neural stem cells (Sox1 and nestin positive cells) was inhibited by high glucose. Neuron (Tuj1 positive cells) and glia (GFAP positive cells) differentiation from GR-E14 cells was also suppressed by high glucose. In addition, high glucose delayed GR-E14 differentiation into neural crest cells by decreasing neural crest markers, paired box 3 (Pax3) and paired box 7 (Pax7). Thus, high glucose impairs ES cell differentiation into neural lineage cells. The low glucose adapted and high glucose responsive GR-E14 cell line is a useful in vitro model for assessing the adverse effect of high glucose on the development of the central nervous system. PMID:26940741

  20. High glucose suppresses embryonic stem cell differentiation into neural lineage cells.

    Science.gov (United States)

    Yang, Penghua; Shen, Wei-bin; Reece, E Albert; Chen, Xi; Yang, Peixin

    2016-04-01

    Abnormal neurogenesis occurs during embryonic development in human diabetic pregnancies and in animal models of diabetic embryopathy. Our previous studies in a mouse model of diabetic embryopathy have implicated that high glucose of maternal diabetes delays neurogenesis in the developing neuroepithelium leading to neural tube defects. However, the underlying process in high glucose-impaired neurogenesis is uncharacterized. Neurogenesis from embryonic stem (ES) cells provides a valuable model for understanding the abnormal neural lineage development under high glucose conditions. ES cells are commonly generated and maintained in high glucose (approximately 25 mM glucose). Here, the mouse ES cell line, E14, was gradually adapted to and maintained in low glucose (5 mM), and became a glucose responsive E14 (GR-E14) line. High glucose induced the endoplasmic reticulum stress marker, CHOP, in GR-E14 cells. Under low glucose conditions, the GR-E14 cells retained their pluripotency and capability to differentiate into neural lineage cells. GR-E14 cell differentiation into neural stem cells (Sox1 and nestin positive cells) was inhibited by high glucose. Neuron (Tuj1 positive cells) and glia (GFAP positive cells) differentiation from GR-E14 cells was also suppressed by high glucose. In addition, high glucose delayed GR-E14 differentiation into neural crest cells by decreasing neural crest markers, paired box 3 (Pax3) and paired box 7 (Pax7). Thus, high glucose impairs ES cell differentiation into neural lineage cells. The low glucose adapted and high glucose responsive GR-E14 cell line is a useful in vitro model for assessing the adverse effect of high glucose on the development of the central nervous system.

  1. In-vivo and ex-vivo inhibition of intestinal glucose uptake: A scope for antihyperglycemia

    Directory of Open Access Journals (Sweden)

    S Viviyan Therasa

    2014-01-01

    Conclusions: The kinetic studies on the glucose transport inhibition across the intestinal membrane by the plant extract was a non competitive type of inhibition of the intestinal glucose transporter protein (GLUT2 and SGLT1 revealing the probable mechanism of hypoglycaemic effect of the aqueous leaf extract of P. amarus .

  2. Chrysobalanus icaco L. Leaves Normalizes Insulin Sensitivity and Blood Glucose and Inhibits Weight Gain in High-Fat Diet-Induced Obese Mice.

    Science.gov (United States)

    White, Pollyanna A S; Araújo, Jessica M D; Cercato, Luana M; Souza, Lucas A; Barbosa, Ana Paula Oliveira; Quintans-Junior, Lucindo José; Machado, Ubiratan F; Camargo, Enilton A; Brito, Luciana C; Santos, Marcio Roberto V

    2016-02-01

    Chrysobalanus icaco L. is a medicinal plant present in the Brazilian coastline and known for its hypoglicemic and antioxidant properties. Here, we assessed the beneficial metabolic effects of the aqueous extract of C. icaco (AECI) leaves in diet-induced obese mice. Swiss mice were fed standard chow (SC used as controls) or high-fat diet (HFD) to induce obesity. After 10 weeks, mice on each diet were divided into two groups with one group used as control while the other group treated with AECI for 4 weeks resulting in four groups of mice: SC; SC treated with AECI (SC + AECI); HFD; and HFD treated with AECI (HFD + AECI). AECI was administered drinking water at about 200 mg/kg. AECI was able to normalize insulin (13,682 ± 1090 vs. 9828 ± 485 AU, P fat storage in liver (72.60 ± 3.83%, P fat intake. These findings reinforce the use of AECI in hyperglycemia and highlight the potential extract's effect in preventing weight gain and fat accumulation in liver of diet-induced obese mice.

  3. High pressure HC1 conversion of cellulose to glucose

    Energy Technology Data Exchange (ETDEWEB)

    Antonoplis, Robert Alexander; Blanch, Harvey W.; Wilke, Charles R.

    1981-08-01

    The production of ethanol from glucose by means of fermentation represents a potential long-range alternative to oil for use as a transportation fuel. Today's rising oil prices and the dwindling world supply of oil have made other fuels, such as ethanol, attractive alternatives. It has been shown that automobiles can operate, with minor alterations, on a 10% ethanol-gasoline mixture popularly known as gasohol. Wood has long been known as a potential source of glucose. Glucose may be obtained from wood following acid hydrolysis. In this research, it was found that saturating wood particles with HCl gas under pressure was an effective pretreatment before subjecting the wood to dilute acid hydrolysis. The pretreatment is necessary because of the tight lattice structure of cellulose, which inhibits dilute acid hydrolysis. HCl gas makes the cellulose more susceptible to hydrolysis and the glucose yield is doubled when dilute acid hydrolysis is preceded by HCl saturation at high pressure. The saturation was most effectively performed in a fluidized bed reactor, with pure HCl gas fluidizing equal volumes of ground wood and inert particles. The fluidized bed effectively dissipated the large amount of heat released upon HCl absorption into the wood. Batch reaction times of one hour at 314.7 p.s.i.a. gave glucose yields of 80% and xylose yields of 95% after dilute acid hydrolysis. A non-catalytic gas-solid reaction model, with gas diffusing through the solid limiting the reaction rate, was found to describe the HCl-wood reaction in the fluidized bed. HCl was found to form a stable adduct with the lignin residue in the wood, in a ratio of 3.33 moles per mole of lignin monomer. This resulted in a loss of 0.1453 lb. of HCl per pound of wood. The adduct was broken upon the addition of water. A process design and economic evaluation for a plant to produce 214 tons per day of glucose from air-dried ground Populus tristi gave an estimated glucose cost of 15.14 cents per pound

  4. Aldose reductase inhibitor improves insulin-mediated glucose uptake and prevents migration of human coronary artery smooth muscle cells induced by high glucose.

    Science.gov (United States)

    Yasunari, K; Kohno, M; Kano, H; Minami, M; Yoshikawa, J

    2000-05-01

    We examined involvement of the polyol pathway in high glucose-induced human coronary artery smooth muscle cell (SMC) migration using Boyden's chamber method. Chronic glucose treatment for 72 hours potentiated, in a concentration-dependent manner (5.6 to 22.2 mol/L), platelet-derived growth factor (PDGF) BB-mediated SMC migration. This potentiation was accompanied by an increase in PDGF BB binding, because of an increased number of PDGF-beta receptors, and this potentiation was blocked by the aldose reductase inhibitor epalrestat. Epalrestat at concentrations of 10 and 100 nmol/L inhibited high glucose-potentiated (22.2 mmol/L), PDGF BB-mediated migration. Epalrestat at 100 nmol/L inhibited a high glucose-induced increase in the reduced/oxidized nicotinamide adenine dinucleotide ratio and membrane-bound protein kinase C (PKC) activity in SMCs. PKC inhibitors calphostin C (100 nmol/L) and chelerythrine (1 micromol/L) each inhibited high glucose-induced, PDGF BB-mediated SMC migration. High glucose-induced suppression of insulin-mediated [(3)H]-deoxyglucose uptake, which was blocked by both calphostin C (100 nmol/L) and chelerythrine (1 micromol/L), was decreased by epalrestat (100 nmol/L). Chronic high glucose treatment for 72 hours increased intracellular oxidative stress, which was directly measured by flow cytometry using carboxydichlorofluorescein diacetate bis-acetoxymethyl ester, and this increase was significantly suppressed by epalrestat (100 nmol/L). Antisense oligonucleotide to PKC-beta isoform inhibited high glucose-mediated changes in SMC migration, insulin-mediated [(3)H]-deoxyglucose uptake, and oxidative stress. These findings suggest that high glucose concentrations potentiate SMC migration in coronary artery and that the aldose reductase inhibitor epalrestat inhibits high glucose-potentiated, PDGF BB-induced SMC migration, possibly through suppression of PKC (PKC-beta), impaired insulin-mediated glucose uptake, and oxidative stress.

  5. Sinomenine alleviates high glucose-induced renal glomerular endothelial hyperpermeability by inhibiting the activation of RhoA/ROCK signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Qingqiao [Renal Department of Internal Medicine, The Third Hospital of Wuhan (China); Xia, Yuanyu, E-mail: xiayuanyu.wh@gmail.com [Renal Department of Internal Medicine, The Third Hospital of Wuhan (China); Wang, Guan [Department of Cardiology, The Second Affiliated Hospital of Guangzhou Medical University (China)

    2016-09-02

    As an early sign of diabetic cardiovascular disease, endothelial dysfunction may contribute to progressive diabetic nephropathy (DN). Endothelial hyperpermeability induced by hyperglycemia (HG) is a central pathogenesis for DN. Sinomenine (SIN) has strong anti-inflammatory and renal protective effects, following an unknown protective mechanism against HG-induced hyperpermeability. We herein explored the role of SIN in vitro in an HG-induced barrier dysfunction model in human renal glomerular endothelial cells (HRGECs). The cells were exposed to SIN and/or HG for 24 h, the permeability of which was significantly increased by HG. Moreover, junction protein occludin in the cell-cell junction area and its total expression in HRGECs were significantly decreased by HG. However, the dysfunction of tight junction and hyperpermeability of HRGECs were significantly reversed by SIN. Furthermore, SIN prevented HG-increased reactive oxygen species (ROS) by activating nuclear factor-E2-related factor 2 (Nrf2). Interestingly, activation of RhoA/ROCK induced by HG was reversed by SIN or ROCK inhibitor. HG-induced hyperpermeability was prevented by SIN. High ROS level, tight junction dysfunction and RhoA/ROCK activation were significantly attenuated with knockdown of Nrf2. Mediated by activation of Nrf2, SIN managed to significantly prevent HG-disrupted renal endothelial barrier function by suppressing the RhoA/ROCK signaling pathway through reducing ROS. We successfully identified a novel pathway via which SIN exerted antioxidative and renal protective functions, and provided a molecular basis for potential SIN applications in treating DN vascular disorders.

  6. Sinomenine alleviates high glucose-induced renal glomerular endothelial hyperpermeability by inhibiting the activation of RhoA/ROCK signaling pathway.

    Science.gov (United States)

    Yin, Qingqiao; Xia, Yuanyu; Wang, Guan

    2016-09-02

    As an early sign of diabetic cardiovascular disease, endothelial dysfunction may contribute to progressive diabetic nephropathy (DN). Endothelial hyperpermeability induced by hyperglycemia (HG) is a central pathogenesis for DN. Sinomenine (SIN) has strong anti-inflammatory and renal protective effects, following an unknown protective mechanism against HG-induced hyperpermeability. We herein explored the role of SIN in vitro in an HG-induced barrier dysfunction model in human renal glomerular endothelial cells (HRGECs). The cells were exposed to SIN and/or HG for 24 h, the permeability of which was significantly increased by HG. Moreover, junction protein occludin in the cell-cell junction area and its total expression in HRGECs were significantly decreased by HG. However, the dysfunction of tight junction and hyperpermeability of HRGECs were significantly reversed by SIN. Furthermore, SIN prevented HG-increased reactive oxygen species (ROS) by activating nuclear factor-E2-related factor 2 (Nrf2). Interestingly, activation of RhoA/ROCK induced by HG was reversed by SIN or ROCK inhibitor. HG-induced hyperpermeability was prevented by SIN. High ROS level, tight junction dysfunction and RhoA/ROCK activation were significantly attenuated with knockdown of Nrf2. Mediated by activation of Nrf2, SIN managed to significantly prevent HG-disrupted renal endothelial barrier function by suppressing the RhoA/ROCK signaling pathway through reducing ROS. We successfully identified a novel pathway via which SIN exerted antioxidative and renal protective functions, and provided a molecular basis for potential SIN applications in treating DN vascular disorders.

  7. Sodium-glucose cotransporter-2 inhibition and the insulin: Glucagon ratio: Unexplored dimensions

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2015-01-01

    Full Text Available The sodium-glucose cotransporter 2 (SGLT-2 inhibitors are a novel class of glucose-lowering drugs which act by inhibiting the reabsorption of filtered glucose from the kidneys. Their effect on insulin and glucagon levels has recently been studied but is not fully explained. This communication proposes various hypotheses: A direct effect of SGLT-2 inhibition on the alpha cell receptors, a paracrine or intra-islet mediated effect on alpha cell sensitivity to glucose, and a calorie restriction mimetic action, to explain the impact of these drugs on the insulin glucagon ratio.

  8. Involvement of functional groups on the surface of carboxyl group-terminated polyamidoamine dendrimers bearing arbutin in inhibition of Na⁺/glucose cotransporter 1 (SGLT1)-mediated D-glucose uptake.

    Science.gov (United States)

    Sakuma, Shinji; Kanamitsu, Shun; Teraoka, Yumi; Masaoka, Yoshie; Kataoka, Makoto; Yamashita, Shinji; Shirasaka, Yoshiyuki; Tamai, Ikumi; Muraoka, Masahiro; Nakatsuji, Yohji; Kida, Toshiyuki; Akashi, Mitsuru

    2012-04-01

    A carboxyl group-terminated polyamidoamine dendrimer (generation: 3.0) bearing arbutin, which is a substrate of Na⁺/glucose cotransporter 1 (SGLT1), via a nonbiodegradable ω-amino triethylene glycol linker (PAMAM-ARB), inhibits SGLT1-mediated D-glucose uptake, as does phloridzin, which is a typical SGLT1 inhibitor. Here, since our previous research revealed that the activity of arbutin was dramatically improved through conjugation with the dendrimer, we examined the involvement of functional groups on the dendrimer surface in inhibition of SGLT1-mediated D-glucose uptake. PAMAM-ARB, with a 6.25% arbutin content, inhibited in vitro D-glucose uptake most strongly; the inhibitory effect decreased as the arbutin content increased. In vitro experiments using arbutin-free original dendrimers indicated that dendrimer-derived carboxyl groups actively participated in SGLT1 inhibition. However, the inhibitory effect was much less than that of PAMAM-ARB and was equal to that of glucose moiety-free PAMAM-ARB. Data supported that the glucose moiety of arbutin was essential for the high activity of PAMAM-ARB in SGLT1 inhibition. Analysis of the balance of each domain further suggested that carboxyl groups anchored PAMAM-ARB to SGLT1, and the subsequent binding of arbutin-derived glucose moieties to the target sites on SGLT1 resulted in strong inhibition of SGLT1-mediated D-glucose uptake.

  9. Vasopressin activates Akt/mTOR pathway in smooth muscle cells cultured in high glucose concentration

    Energy Technology Data Exchange (ETDEWEB)

    Montes, Daniela K.; Brenet, Marianne; Muñoz, Vanessa C.; Burgos, Patricia V.; Villanueva, Carolina I. [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Figueroa, Carlos D. [Department of Anatomy, Histology and Pathology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); González, Carlos B., E-mail: cbgonzal@uach.cl [Department of Physiology, Universidad Austral de Chile, Valdivia 509-9200 (Chile); Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, TX 77555 (United States)

    2013-11-29

    Highlights: •AVP induces mTOR phosphorylation in A-10 cells cultured in high glucose concentration. •The mTOR phosphorylation is mediated by the PI3K/Akt pathway activation. •The AVP-induced mTOR phosphorylation inhibited autophagy and stimulated cell proliferation. -- Abstract: Mammalian target of rapamycin (mTOR) complex is a key regulator of autophagy, cell growth and proliferation. Here, we studied the effects of arginine vasopressin (AVP) on mTOR activation in vascular smooth muscle cells cultured in high glucose concentration. AVP induced the mTOR phosphorylation in A-10 cells grown in high glucose, in contrast to cells cultured in normal glucose; wherein, only basal phosphorylation was observed. The AVP-induced mTOR phosphorylation was inhibited by a PI3K inhibitor. Moreover, the AVP-induced mTOR activation inhibited autophagy and increased thymidine incorporation in cells grown in high glucose. This increase was abolished by rapamycin which inhibits the mTORC1 complex formation. Our results suggest that AVP stimulates mTOR phosphorylation by activating the PI3K/Akt signaling pathway and, subsequently, inhibits autophagy and raises cell proliferation in A-10 cells maintained in high glucose concentration.

  10. TGR5 suppresses high glucose-induced upregulation of fibronectin and transforming growth factor-β1 in rat glomerular mesangial cells by inhibiting RhoA/ROCK signaling.

    Science.gov (United States)

    Xiong, Fengxiao; Li, Xuejuan; Yang, Zhiying; Wang, Yu; Gong, Wenyan; Huang, Junying; Chen, Cheng; Liu, Peiqing; Huang, Heqing

    2016-12-01

    RhoA/ROCK can cause renal inflammation and fibrosis in the context of diabetes by activating nuclear factor-κB (NF-κB). TGR5 is known for its role in maintaining metabolic homeostasis and anti-inflammation, which is closely related to NF-κB inhibition. Given that TGR5 is highly enriched in kidney, we aim to investigate the regulatory role of TGR5 on fibronectin (FN) and transforming growth factor-β1 (TGF-β1) in high glucose (HG)-treated rat glomerular mesangial cells (GMCs). Both the factors are closely related to renal inflammations and mediated by NF-κB. Moreover, our study determines whether such regulation is achieved by the inhibition of RhoA/ROCK and the subsequent NF-κB suppression. Polymerase chain reaction was taken to test the mRNA level of TGR5. Western blot was used to measure the protein expressions of TGR5, FN, TGF-β1, p65, IκBα, phospho-MYPT1 (Thr853), and MYPT1. Glutathione S-transferase-pull down and immunofluorescence were conducted to test the activation of RhoA, the distribution of TGR5, and p65, respectively. Electrophoretic mobility shift assay was adopted to measure the DNA binding activity of NF-κB. In GMCs, TGR5 activation or overexpression significantly suppressed FN and TGF-β1 protein expressions, NF-κB, and RhoA/ROCK activation induced by HG or transfection of constitutively active RhoA. By contrast, TGR5 RNA interference caused enhancement of FN, TGF-β1 protein expressions, increase of RhoA/ROCK activation. However, TGR5 cannot suppress RhoA/ROCK activation when a selective Protein kinase A (PKA) inhibitor was used. This study suggests that in HG-treated GMCs, TGR5 significantly suppresses the NF-κB-mediated upregulation of FN and TGF-β1, which are hallmarks of diabetic nephropathy. These functions are closely related to the suppression of RhoA/ROCK via PKA.

  11. Fatty acyl-CoA esters inhibit glucose-6-phosphatase in rat liver microsomes.

    Science.gov (United States)

    Fulceri, R; Gamberucci, A; Scott, H M; Giunti, R; Burchell, A; Benedetti, A

    1995-01-01

    In native rat liver microsomes glucose 6-phosphatase activity is dependent not only on the activity of the glucose-6-phosphatase enzyme (which is lumenal) but also on the transport of glucose-6-phosphate, phosphate and glucose through the respective translocases T1, T2 and T3. By using enzymic assay techniques, palmitoyl-CoA or CoA was found to inhibit glucose-6-phosphatase activity in intact microsomes. The effect of CoA required ATP and fatty acids to form fatty acyl esters. Increasing concentrations (2-50 microM) of CoA (plus ATP and 20 microM added palmitic acid) or of palmitoyl-CoA progressively decreased glucose-6-phosphatase activity to 50% of the control value. The inhibition lowered the Vmax without significantly changing the Km. A non-hydrolysable analogue of palmitoyl-CoA also inhibited, demonstrating that binding of palmitoyl-CoA rather than hydrolysis produces the inhibition. Light-scattering measurements of osmotically induced changes in the size of rat liver microsomal vesicles pre-equilibrated in a low-osmolality buffer demonstrated that palmitoyl-CoA alone or CoA plus ATP and palmitic acid altered the microsomal permeability to glucose 6-phosphate, but not to glucose or phosphate, indicating that T1 is the site of palmitoyl-CoA binding and inhibition of glucose-6-phosphatase activity in native microsomes. The type of inhibition found suggests that liver microsomes may comprise vesicles heterogeneous with respect to glucose-6-phosphate translocase(s), i.e. sensitive or insensitive to fatty acid ester inhibition. PMID:7733874

  12. Permeabilization and inhibition of the germination of spores of Aspergillus niger for gluconic acid production from glucose.

    Science.gov (United States)

    Ramachandran, Sumitra; Fontanille, Pierre; Pandey, Ashok; Larroche, Christian

    2008-07-01

    In this study, the role of citral to permeabilize the spores of Aspergillus niger and replace sodium azide in the bioconversion medium was studied. Further, characterization of glucose oxidase of spores was carried out by exposing both permeabilized and unpermeabilized spores to different pressures (1, 2, 2.7 kb) and temperatures (60, 70, 80, 90 degrees C). Unpermeabilized spores after exposure to high temperatures were permeabilized by freezing before using as catalyst in the bioconversion reaction. Results showed that citral permeabilized the spores and could inhibit spore germination in the bioconversion medium. Rate of reaction was significantly increased from 1.5 to 4.35 g/Lh which was higher than the commercial glucose oxidase 2g/Lh). Glucose oxidase activity of A. niger was resistant to pressure. However, pressure treatment could not permeabilize them. Behaviour of fresh and permeabilized spores to temperature varied significantly. Glucose oxidase activity of fresh spores exposed to high temperature was unaffected at 70 degrees C till 15 min and 84% of relative activity was retained even after 1h at 70 degrees C while permeabilized spore got inactivated at 70 degrees C for 15 min, which followed the same pattern as commercial glucose oxidase. Cellular membrane integrity was lost due to permeabilization by freezing which resulted in heat-inactivation of glucose oxidase when spores were permeabilized before heat treatment. Thus, glucose oxidase of spore remains heat stable when unpermeabilized and active while permeabilized and its reaction rate is higher than the commercial glucose oxidase.

  13. Niclosamide reduces glucagon sensitivity via hepatic PKA inhibition in obese mice: Implications for glucose metabolism improvements in type 2 diabetes

    Science.gov (United States)

    Chowdhury, Md. Kamrul Hasan; Turner, Nigel; Bentley, Nicholas L.; Das, Abhirup; Wu, Lindsay E.; Richani, Dulama; Bustamante, Sonia; Gilchrist, Robert B.; Morris, Margaret J.; Shepherd, Peter R.; Smith, Greg C.

    2017-01-01

    Type 2 diabetes (T2D) is a global pandemic. Currently, the drugs used to treat T2D improve hyperglycemic symptom of the disease but the underlying mechanism causing the high blood glucose levels have not been fully resolved. Recently published data showed that salt form of niclosamide improved glucose metabolism in high fat fed mice via mitochondrial uncoupling. However, based on our previous work we hypothesised that niclosamide might also improve glucose metabolism via inhibition of the glucagon signalling in liver in vivo. In this study, mice were fed either a chow or high fat diet containing two different formulations of niclosamide (niclosamide ethanolamine salt - NENS or niclosamide - Nic) for 10 weeks. We identified both forms of niclosamide significantly improved whole body glucose metabolism without altering total body weight or body composition, energy expenditure or insulin secretion or sensitivity. Our study provides evidence that inhibition of the glucagon signalling pathway contributes to the beneficial effects of niclosamide (NENS or Nic) on whole body glucose metabolism. In conclusion, our results suggest that the niclosamide could be a useful adjunctive therapeutic strategy to treat T2D, as hepatic glucose output is elevated in people with T2D and current drugs do not redress this adequately. PMID:28054648

  14. Oral glucose intake inhibits hypothalamic neuronal activity more effectively than glucose infusion

    NARCIS (Netherlands)

    Smeets, P.A.M.; Vidarsdottir, S.; Graaf, C. de; Stafleu, A.; Osch, M.J.P. van; Viergever, M.A.; Pijl, H.; Grond, J. van der

    2007-01-01

    We previously showed that hypothalamic neuronal activity, as measured by the blood oxygen level-dependent (BOLD) functional MRI signal, declines in response to oral glucose intake. To further explore the mechanism driving changes in hypothalamic neuronal activity in response to an oral glucose load,

  15. Intracerebroventricular neuropeptide Y infusion precludes inhibition of glucose and VLDL production by insulin.

    NARCIS (Netherlands)

    Hoek, A.M. van den; Voshol, P.J.; Karnekamp, B.N.; Buijs, R.M.; Romijn, J.A.; Havekes, L.M.; Pijl, H.

    2004-01-01

    Recent evidence demonstrates that hypothalamic insulin signaling is required for inhibition of endogenous glucose production. The downstream mechanisms that are responsible for the effects of hypothalamic insulin receptor activation on hepatic fuel flux remain to be determined. To establish whether

  16. Catecholamine-induced lipolysis causes mTOR complex dissociation and inhibits glucose uptake in adipocytes.

    Science.gov (United States)

    Mullins, Garrett R; Wang, Lifu; Raje, Vidisha; Sherwood, Samantha G; Grande, Rebecca C; Boroda, Salome; Eaton, James M; Blancquaert, Sara; Roger, Pierre P; Leitinger, Norbert; Harris, Thurl E

    2014-12-09

    Anabolic and catabolic signaling oppose one another in adipose tissue to maintain cellular and organismal homeostasis, but these pathways are often dysregulated in metabolic disorders. Although it has long been established that stimulation of the β-adrenergic receptor inhibits insulin-stimulated glucose uptake in adipocytes, the mechanism has remained unclear. Here we report that β-adrenergic-mediated inhibition of glucose uptake requires lipolysis. We also show that lipolysis suppresses glucose uptake by inhibiting the mammalian target of rapamycin (mTOR) complexes 1 and 2 through complex dissociation. In addition, we show that products of lipolysis inhibit mTOR through complex dissociation in vitro. These findings reveal a previously unrecognized intracellular signaling mechanism whereby lipolysis blocks the phosphoinositide 3-kinase-Akt-mTOR pathway, resulting in decreased glucose uptake. This previously unidentified mechanism of mTOR regulation likely contributes to the development of insulin resistance.

  17. In-vivo andex-vivo inhibition of intestinal glucose uptake:A scope for antihyperglycemia

    Institute of Scientific and Technical Information of China (English)

    S Viviyan Therasa; T Thirumalai; N Tamilselvan; E David

    2014-01-01

    Objective:To study hypoglycemic effect ofPhyllanthus amarus (P. amarus) leaf extract and its glucose uptake inhibition effect in rat small intestineex-vivo andin vivo models.Methods:Hypoglycemic studies were carried out in glucose loaded and streptozotocin(STZ) induced diabeticalbino rats.Blood glucose levels were estimated atI,III andIV hour time intervals after administration of aqueous leaf extract ofP. amarus.The study on the effect of plant extract on intestinal glucose absorption in rat was carried out using everted gut sacs.Results:The blood glucose levels were significantly depleted in the animals administered with aqueous leaf extract ofP. amarus(250 mg/kg body weight).Incubation of the rat everted intestinal sacs with the aqueous leaf extract ofP. amarus resulted in the inhibition of glucose transport across the intestinal membrane.Conclusions:The kinetic studies on the glucose transport inhibition across the intestinal membrane by the plant extract was a non competitive type of inhibition of the intestinal glucose transporter protein(GLUT2 andSGLT1) revealing the probable mechanism of hypoglycaemic effect of the aqueous leaf extract ofP. amarus.

  18. Glucose inhibits root meristem growth via ABA INSENSITIVE 5, which represses PIN1 accumulation and auxin activity in Arabidopsis.

    Science.gov (United States)

    Yuan, Ting-Ting; Xu, Heng-Hao; Zhang, Kun-Xiao; Guo, Ting-Ting; Lu, Ying-Tang

    2014-06-01

    Glucose functions as a hormone-like signalling molecule that modulates plant growth and development in Arabidopsis thaliana. However, the role of glucose in root elongation remains elusive. Our study demonstrates that high concentrations of glucose reduce the size of the root meristem zone by repressing PIN1 accumulation and thereby reducing auxin levels. In addition, we verified the involvement of ABA INSENSITIVE 5 (ABI5) in this process by showing that abi5-1 is less sensitive to glucose than the wild type, whereas glucose induces ABI5 expression and the inducible overexpression of ABI5 reduces the size of the root meristem zone. Furthermore, the inducible overexpression of ABI5 in PIN1::PIN1-GFP plants reduces the level of PIN1-GFP, but glucose reduces the level of PIN1-GFP to a lesser extent in abi5-1 PIN1::PIN1-GFP plants than in the PIN1::PIN1-GFP control, suggesting that ABI5 is involved in glucose-regulated PIN1 accumulation. Taken together, our data suggest that ABI5 functions in the glucose-mediated inhibition of the root meristem zone by repressing PIN1 accumulation, thus leading to reduced auxin levels in roots. © 2013 John Wiley & Sons Ltd.

  19. Vav3, a GEF for RhoA, Plays a Critical Role under High Glucose Conditions

    Directory of Open Access Journals (Sweden)

    Jie Sha

    2014-09-01

    Full Text Available BackgroundThe role of small GTPase molecules is poorly understood under high glucose conditions.MethodsWe analyzed the expression pattern of Vav3 in skeletal muscle C2C12 cells under high glucose culture condition with reverse transcription-polymerase chain reaction and Western blot analysis. We also measured glucose uptake using isotope-labelled glucose.ResultsWe showed that expression of Vav3 (a guanine nucleotide exchange factor for RhoA increased. mRNA and protein levels in skeletal muscle C2C12 cells under high glucose conditions. The AMP-activated protein kinase (AMPK activator AMPK agonist 5-aminoimidazole-4-carboxy-amide-1-d-ribofuranoside (AICAR suppressed high glucose-induced Vav3 induction. In addition, exposure of cells to high glucose concentration increased the phosphorylation of PAK-1, a molecule downstream of RhoA. The phosphorylation of paxillin, a downstream molecule of PAK-1, was also increased by exposure to high glucose. Phosphorylation of these molecules was not observed in the presence of AICAR, indicating that AMPK is involved in the RhoA signal pathway under high glucose conditions. Knock down of Vav3 enhances metformin-mediated glucose uptake. Inhibition of AMPK blocked the increases of Vav3 knock down-induced glucose uptake. Metformin-mediated Glut4 translocation was also increased by Vav3 knock-down, suggesting that Vav3 is involved in metformin-mediated glucose uptake.ConclusionThese results demonstrate that Vav3 is involved in the process of metformin-mediated glucose regulation.

  20. The Effect of Angiotensin-Converting Enzyme Inhibition Using Captopril on Energy Balance and Glucose Homeostasis

    Science.gov (United States)

    de Kloet, Annette D.; Krause, Eric G.; Kim, Dong-Hoon; Sakai, Randall R.; Seeley, Randy J.; Woods, Stephen C.

    2009-01-01

    Increasing evidence suggests that the renin-angiotensin-system contributes to the etiology of obesity. To evaluate the role of the renin-angiotensin-system in energy and glucose homeostasis, we examined body weight and composition, food intake, and glucose tolerance in rats given the angiotensin-converting enzyme inhibitor, captopril (∼40 mg/kg · d). Rats given captopril weighed less than controls when fed a high-fat diet (369.3 ± 8.0 vs. 441.7 ± 8.5 g after 35 d; P captopril ate significantly less [3110.3 ± 57.8 vs. 3592.4 ± 88.8 kcal (cumulative 35 d high fat diet intake); P captopril caused animals to defend a lower body weight, animals in both groups were fasted for 24 h and subsequently restricted to 20% of their intake for 2 d. When free food was returned, captopril and control rats returned to their respective body weights and elicited comparable hyperphagic responses. These results suggest that angiotensin-converting enzyme inhibition protects against the development of diet-induced obesity and glucose intolerance. PMID:19497971

  1. 1,2,3,4,6 Penta-O-galloyl-β-d-glucose, a bioactivity guided isolated compound from Mangifera indica inhibits 11β-HSD-1 and ameliorates high fat diet-induced diabetes in C57BL/6 mice.

    Science.gov (United States)

    Mohan, C G; Viswanatha, G L; Savinay, G; Rajendra, C E; Halemani, Praveen D

    2013-03-15

    Methanolic leaf extract of Mangifera indica (MEMI) was subjected to bioactivity guided fractionation in order to identify the active antidiabetic constituent. 32 fractions were evaluated for possible 11β-HSD-1 inhibition activity under in vitro conditions. The EA-7/8-9/10-4 fraction was evolved as a most potent fraction among all the fractions and it was identified as well known gallotannin compound 1,2,3,4,6 penta-O-galloyl-β-d-glucose (PGG) by spectral analysis. Based on these results the PGG was further evaluated in ex vivo 11β-HSD-1 inhibition assay and high fat diet (HFD)-induced diabetes in male C57BL/6 mice. Single dose (10, 25, 50 and 100mg/kg) of PGG and carbenoxolone (CBX) have dose dependently inhibited the 11β-HSD-1 activity in liver and adipose tissue. Furthermore, HFD appraisal to male C57BL/6 mice caused severe hyperglycemia, hypertriglyceridemia, elevated levels of plasma corticosterone and insulin, increased liver and white adipose mass with increase in body weight was observed compare to normal control. Also, oral glucose tolerance was significantly impaired compare to normal control. Interestingly, post-treatment with PGG for 21 days had alleviated the HFD-induced biochemical alterations and improved oral glucose tolerance compare to HFD-control. In conclusion, the PGG isolated from MEMI inhibits 11β-HSD-1 activity and ameliorates HFD-induced diabetes in male C57BL/6 mice.

  2. Methamphetamine inhibits the glucose uptake by human neurons and astrocytes: stabilization by acetyl-L-carnitine.

    Directory of Open Access Journals (Sweden)

    P M Abdul Muneer

    Full Text Available Methamphetamine (METH, an addictive psycho-stimulant drug exerts euphoric effects on users and abusers. It is also known to cause cognitive impairment and neurotoxicity. Here, we hypothesized that METH exposure impairs the glucose uptake and metabolism in human neurons and astrocytes. Deprivation of glucose is expected to cause neurotoxicity and neuronal degeneration due to depletion of energy. We found that METH exposure inhibited the glucose uptake by neurons and astrocytes, in which neurons were more sensitive to METH than astrocytes in primary culture. Adaptability of these cells to fatty acid oxidation as an alternative source of energy during glucose limitation appeared to regulate this differential sensitivity. Decrease in neuronal glucose uptake by METH was associated with reduction of glucose transporter protein-3 (GLUT3. Surprisingly, METH exposure showed biphasic effects on astrocytic glucose uptake, in which 20 µM increased the uptake while 200 µM inhibited glucose uptake. Dual effects of METH on glucose uptake were paralleled to changes in the expression of astrocytic glucose transporter protein-1 (GLUT1. The adaptive nature of astrocyte to mitochondrial β-oxidation of fatty acid appeared to contribute the survival of astrocytes during METH-induced glucose deprivation. This differential adaptive nature of neurons and astrocytes also governed the differential sensitivity to the toxicity of METH in these brain cells. The effect of acetyl-L-carnitine for enhanced production of ATP from fatty oxidation in glucose-free culture condition validated the adaptive nature of neurons and astrocytes. These findings suggest that deprivation of glucose-derived energy may contribute to neurotoxicity of METH abusers.

  3. Polyamines regulate cell growth and cellular methylglyoxal in high-glucose medium independently of intracellular glutathione.

    Science.gov (United States)

    Kwak, Min-Kyu; Lee, Mun-Hyoung; Park, Seong-Jun; Shin, Sang-Min; Liu, Rui; Kang, Sa-Ouk

    2016-03-01

    Polyamines can presumably inhibit protein glycation, when associated with the methylglyoxal inevitably produced during glycolysis. Herein, we hypothesized a nonenzymatic interaction between putrescine and methylglyoxal in putrescine-deficient or -overexpressing Dictyostelium cells in high-glucose medium, which can control methylglyoxal production. Putrescine was essentially required for growth rescue accompanying methylglyoxal detoxification when cells underwent growth defect and cell cycle G1-arrest when supplemented with high glucose. Furthermore, methylglyoxal regulation by putrescine seemed to be a parallel pathway independent of the changes in cellular glutathione content in high-glucose medium. Consequently, we suggest that Dictyostelium cells need polyamines for normal growth and cellular methylglyoxal regulation.

  4. Inhibitory Effects of Ecklonia cava Extract on High Glucose-Induced Hepatic Stellate Cell Activation

    Directory of Open Access Journals (Sweden)

    Akiko Kojima-Yuasa

    2011-12-01

    Full Text Available Nonalcoholic steatohepatitis (NASH is a disease closely associated with obesity and diabetes. A prevalence of type 2 diabetes and a high body mass index in cryptogenic cirrhosis may imply that obesity leads to cirrhosis. Here, we examined the effects of an extract of Ecklonia cava, a brown algae, on the activation of high glucose-induced hepatic stellate cells (HSCs, key players in hepatic fibrosis. Isolated HSCs were incubated with or without a high glucose concentration. Ecklonia cava extract (ECE was added to the culture simultaneously with the high glucose. Treatment with high glucose stimulated expression of type I collagen and α-smooth muscle actin, which are markers of activation in HSCs, in a dose-dependent manner. The activation of high glucose-treated HSCs was suppressed by the ECE. An increase in the formation of intracellular reactive oxygen species (ROS and a decrease in intracellular glutathione levels were observed soon after treatment with high glucose, and these changes were suppressed by the simultaneous addition of ECE. High glucose levels stimulated the secretion of bioactive transforming growth factor-β (TGF-β from the cells, and the stimulation was also suppressed by treating the HSCs with ECE. These results suggest that the suppression of high glucose-induced HSC activation by ECE is mediated through the inhibition of ROS and/or GSH and the downregulation of TGF-β secretion. ECE is useful for preventing the development of diabetic liver fibrosis.

  5. Glucose-dependent insulinotropic polypeptide inhibits bone resorption in humans

    DEFF Research Database (Denmark)

    Nissen, Anne; Christensen, Mikkel; Knop, Filip K

    2014-01-01

    -minute glucose clamps with co-infusion of GIP (4 pmol/kg/min for 15 min, followed by 2 pmol/kg/min for 45 min) or placebo. The samples were analyzed for concentrations of degradation products of C-terminal telopeptide of type I collagen (CTX), a bone resorption marker. RESULTS regarding effects...

  6. Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect

    Science.gov (United States)

    Kalra, Sanjay; Jain, Arpit; Ved, Jignesh; Unnikrishnan, A. G.

    2016-01-01

    This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2) inhibition: Calorie restriction mimicry (CRM) and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a “good person,” who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production. PMID:27730088

  7. Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect.

    Science.gov (United States)

    Kalra, Sanjay; Jain, Arpit; Ved, Jignesh; Unnikrishnan, A G

    2016-01-01

    This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2) inhibition: Calorie restriction mimicry (CRM) and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a "good person," who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production.

  8. Sodium-glucose cotransporter 2 inhibition and health benefits: The Robin Hood effect

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2016-01-01

    Full Text Available This review discusses two distinct, yet related, mechanisms of sodium-glucose cotransporter 2 (SGLT2 inhibition: Calorie restriction mimicry (CRM and pro-ketogenic effect, which may explain their cardiovascular benefits. We term these adaptive CRM and pro-ketogenic effects of SGLT2 inhibition, the Robin Hood hypothesis. In English history, Robin Hood was a "good person," who stole from the rich and helped the poor. He supported redistribution of resources as he deemed fit for the common good. In a similar fashion, SGLT2 inhibition provides respite to the overloaded glucose metabolism while utilizing lipid stores for energy production.

  9. Designing a highly active soluble PQQ-glucose dehydrogenase for efficient glucose biosensors and biofuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Durand, Fabien [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France); Stines-Chaumeil, Claire [Universite de Bordeaux, CNRS, Institut de Biochimie et de Genetique Cellulaires, 1 rue Camille Saint Saens, 33077 Bordeaux Cedex (France); Flexer, Victoria [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France); Andre, Isabelle [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); CNRS, UMR5504, F-31400 Toulouse (France); INRA, UMR 792 Ingenierie des Systemes Biologiques et des Procedes, F-31400 Toulouse (France); Mano, Nicolas, E-mail: mano@crpp-bordeaux.cnrs.fr [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France)

    2010-11-26

    Research highlights: {yields} A new mutant of PQQ-GDH designed for glucose biosensors application. {yields} First mutant of PQQ-GDH with higher activity for D-glucose than the Wild type. {yields} Position N428 is a key point to increase the enzyme activity. {yields} Molecular modeling shows that the N428 C mutant displays a better interaction for PQQ than the WT. -- Abstract: We report for the first time a soluble PQQ-glucose dehydrogenase that is twice more active than the wild type for glucose oxidation and was obtained by combining site directed mutagenesis, modelling and steady-state kinetics. The observed enhancement is attributed to a better interaction between the cofactor and the enzyme leading to a better electron transfer. Electrochemical experiments also demonstrate the superiority of the new mutant for glucose oxidation and make it a promising enzyme for the development of high-performance glucose biosensors and biofuel cells.

  10. A kinetics modeling study on the inhibition of glucose on cellulosome of Clostridium thermocellum.

    Science.gov (United States)

    Zhang, Pengcheng; Wang, Buyun; Xiao, Qunfang; Wu, Shan

    2015-08-01

    A simplified kinetics model was built to study the inhibition of glucose on cellulosome of Clostridium thermocellum. Suitable reaction conditions were adopted to evaluate the model. The model was evaluated at different temperatures and further with various activated carbon additions as adsorbent for glucose. Investigation results revealed that the model could describe the hydrolysis kinetics of cellulose by cellulosome quite well. Glucose was found to be an inhibitor for cellulosome based on the kinetics analysis. Inhibition increased with the increase in temperature. Activated carbon as adsorbent could lower the inhibition. Parameters in the model were further discussed based on the experiment. The model might also be used to describe the strong inhibition of cellobiose on cellulosome. Saccharification of cellulose by both cellulosome and C. thermocellum could be enhanced efficiently by activated carbon addition.

  11. Metformin inhibits nuclear factor-κB activation and inflammatory cytokines expression induced by high glucose via adenosine monophosphate-activated protein kinase activation in rat glomerular mesangial cells in vitro

    Institute of Scientific and Technical Information of China (English)

    Gu Junfei; Ye Shandong; Wang Shan; Sun Wenjia; Hu Yuanyuan

    2014-01-01

    Background The renoprotective mechanisms of adenosine monophosphate (AMP)-activated protein kinase (AMPK) agonist-metformin have not been stated clearly.We hypothesized that metformin may ameliorate inflammation via AMPK interaction with critical inflammatory cytokines The aim of this study was to observe the effects of metformin on expression of nuclear factor-κB (NF-κB),monocyte chemoattractant protein-1 (MCP-1),intercellular adhesion molecule-1 (ICAM-1) and transforming growth factor-beta 1 (TGF-β1) induced by high glucose (HG) in cultured rat glomerular mesangial cells (MCs).Methods MCs were cultured in the medium with normal concentration glucose (group NG,5.6 mmol/L),high concentration glucose (group HG,25 mmol/L) and different concentrations of metformin (group M1,M2,M3).After 48-hour exposure,the supernatants and MCs were collected.The expression of NF-κB,MCP-1,ICAM-1,and TGF-β1 mRNA was analyzed by real time polymerase chain reaction.Westem blotting was used to detect the expression of AMPK,phospho-Thr-172 AMPK (p-AMPK),NF-κB p65,MCP-1,ICAM-1,and TGF-β1 protein.Results After stimulated by HG,the expression of NF-κB,MCP-1,ICAM-1,TGF-β1 mRNA and protein of MCs in group HG increased significantly compared with group NG (P <0.05).Both genes and protein expression of NF-κB,MCP-1,ICAM-1,TGF-β1 of MCs induced by high glucose were markedly reduced after metformin treatment in a dose-dependent manner (P <0.05).The expression of p-AMPK increased with the rising of metformin concentration,presenting the opposite trend,while the level of total-AMPK protein was unchanged with exposure to HG or metformin.Conlusion Metformin can suppress the expression of NF-κB,MCP-1,ICAM-1 and TGF-β1 of glomerular MCs induced by high glucose via AMPK activation,which may partlv contribute to its reno-protection.

  12. Inhibition of glucose turnover by 3-bromopyruvate counteracts pancreatic cancer stem cell features and sensitizes cells to gemcitabine.

    Science.gov (United States)

    Isayev, Orkhan; Rausch, Vanessa; Bauer, Nathalie; Liu, Li; Fan, Pei; Zhang, Yiyao; Gladkich, Jury; Nwaeburu, Clifford C; Mattern, Jürgen; Mollenhauer, Martin; Rückert, Felix; Zach, Sebastian; Haberkorn, Uwe; Gross, Wolfgang; Schönsiegel, Frank; Bazhin, Alexandr V; Herr, Ingrid

    2014-07-15

    According to the cancer stem cell (CSC) hypothesis, the aggressive growth and early metastasis of pancreatic ductal adenocarcinoma (PDA) is due to the activity of CSCs, which are not targeted by current therapies. Otto Warburg suggested that the growth of cancer cells is driven by a high glucose metabolism. Here, we investigated whether glycolysis inhibition targets CSCs and thus may enhance therapeutic efficacy. Four established and 3 primary PDA cell lines, non-malignant cells, and 3 patient-tumor-derived CSC-enriched spheroidal cultures were analyzed by glucose turnover measurements, MTT and ATP assays, flow cytometry of ALDH1 activity and annexin positivity, colony and spheroid formation, western blotting, electrophoretic mobility shift assay, xenotransplantation, and immunohistochemistry. The effect of siRNA-mediated inhibition of LDH-A and LDH-B was also investigated. The PDA cells exhibited a high glucose metabolism, and glucose withdrawal or LDH inhibition by siRNA prevented growth and colony formation. Treatment with the anti-glycolytic agent 3-bromopyruvate almost completely blocked cell viability, self-renewal potential, NF-κB binding activity, and stem cell-related signaling and reverted gemcitabine resistance. 3-bromopyruvate was less effective in weakly malignant PDA cells and did not affect non-malignant cells, predicting minimal side effects. 3-bromopyruvate inhibited in vivo tumor engraftment and growth on chicken eggs and mice and enhanced the efficacy of gemcitabine by influencing the expression of markers of proliferation, apoptosis, self-renewal, and metastasis. Most importantly, primary CSC-enriched spheroidal cultures were eliminated by 3-bromopyruvate. These findings propose that CSCs may be specifically dependent on a high glucose turnover and suggest 3-bromopyruvate for therapeutic intervention.

  13. High Glucose Enhances Isoflurane-Induced Neurotoxicity by Regulating TRPC-Dependent Calcium Influx.

    Science.gov (United States)

    Liu, ZhongJie; Ma, ChangQing; Zhao, Wei; Zhang, QingGuo; Xu, Rui; Zhang, HongFei; Lei, HongYi; Xu, ShiYuan

    2017-01-06

    Isoflurane is a commonly used inhalational anesthetic that can induce neurotoxicity via elevating cytosolic calcium (Ca(2+)). High glucose regulates the expression of a family of non-selective cation channels termed transient receptor potential canonical (TRPC) channels that may contribute to Ca(2+) influx. In the present study, we investigated whether high glucose enhances isoflurane-induced neurotoxicity by regulating TRPC-dependent Ca(2+) influx. First, we evaluated toxic damage in mice primary cultured hippocampal neurons and human neuroblastoma cells (SH-SY5Y cells) after hyperglycemia and isoflurane exposure. Next, we investigated cytosolic Ca(2+) concentrations, TRPC mRNA expression levels and tested the effect of the TRPC channel blocker SKF96365 on cytosolic Ca(2+) levels in cells treated with high glucose or/and isoflurane. Finally, we employed knocked down TRPC6 to demonstrate the role of TRPC in high glucose-mediated enhancement of isoflurane-induced neurotoxicity. The results showed that high glucose could enhance isoflurane-induecd toxic damage in primary hippocampal neurons and SH-SY5Y cells. High glucose enhanced the isoflurane-induced increase of cytosolic Ca(2+) in SH-SY5Y cells. High glucose elevated TRPC mRNA expression, especially that of TRPC6. SKF96365 and knock down of TRPC6 were able to inhibit the high glucose-induced increase of cytosolic Ca(2+) and decrease isoflurane-induced neurotoxicity in SH-SY5Y cells cultured with high glucose. Our findings indicate that high glucose could elevate TRPC expression, thus increasing Ca(2+) influx and enhancing isoflurane-induced neurotoxicity.

  14. Fentanyl inhibits glucose-stimulated insulin release from β-cells in rat pancreatic islets

    Institute of Scientific and Technical Information of China (English)

    Tao-Lai Qian; Xin-Hua Wang; Sheng Liu; Liang Ma; Ying Lu

    2009-01-01

    AIM:To explore the effects of fentanyl on insulin release from freshly isolated rat pancreatic islets in static culture.METHODS: Islets were isolated from the pancreas of mature Sprague Dawley rats by common bile duct intraductal collagenase V digestion and were purified by discontinuous Ficoll density gradient centrifugation.The islets were divided into four groups according to the fentanyl concentration: control group (0 ng/mL),group Ⅰ (0.3 ng/mL), group Ⅱ (3.0 ng/mL), and group Ⅲ (30 ng/mL). In each group, the islets were co-cultured for 48 h with drugs under static conditions with fentanyl alone, fentanyl + 0.1 μg/mL naloxone or fentanyl + 1.0 μg/mL naloxone. Cell viability was assessed by the MTT assay. Insulin release in response to low and high concentrations (2.8 mmol/L and 16.7 mmol/L,respectively) of glucose was investigated and electron microscopy morphological assessment was performed.RESULTS: Low- and high-glucose-stimulated insulin release in the control group was significantly higher than in groups Ⅱ and Ⅲ (62.33 ±9.67 μIU vs 47.75 ±96.17 ± 14.17 μIU, 75.17 ± 13.57 μIU, respectively, P <0.01) and was lowest in group Ⅲ ( P < 0.01). After adding 1 μg/mL naloxone, insulin release in groups Ⅱ and Ⅲ was not different from the control group. Electron microscopy studies showed that the islets were damaged by 30 ng/mL fentanyl.CONCLUSION: Fentanyl inhibited glucose-stimulated insulin release from rat islets, which could be prevented by naloxone. Higher concentrations of fentanyl significantly damaged β-cells of rat islets.howed that the isl

  15. Indirect Determination of Mercury Ion by Inhibition of a Glucose Biosensor Based on ZnO Nanorods

    Directory of Open Access Journals (Sweden)

    Magnus Willander

    2012-11-01

    Full Text Available A potentiometric glucose biosensor based on immobilization of glucose oxidase (GOD on ZnO nanorods (ZnO-NRs has been developed for the indirect determination of environmental mercury ions. The ZnO-NRs were grown on a gold coated glass substrate by using the low temperature aqueous chemical growth (ACG approach. Glucose oxidase in conjunction with a chitosan membrane and a glutaraldehyde (GA were immobilized on the surface of the ZnO-NRs using a simple physical adsorption method and then used as a potentiometric working electrode. The potential response of the biosensor between the working electrode and an Ag/AgCl reference electrode was measured in a 1mM phosphate buffer solution (PBS. The detection limit of the mercury ion sensor was found to be 0.5 nM. The experimental results provide two linear ranges of the inhibition from 0.5 × 10−6 mM to 0.5 × 10−4 mM, and from 0.5 × 10−4 mM to 20 mM of mercury ion for fixed 1 mM of glucose concentration in the solution. The linear range of the inhibition from 10−3 mM to 6 mM of mercury ion was also acquired for a fixed 10 mM of glucose concentration. The working electrode can be reactivated by more than 70% after inhibition by simply dipping the used electrode in a 10 mM PBS solution for 7 min. The electrodes retained their original enzyme activity by about 90% for more than three weeks. The response to mercury ions was highly sensitive, selective, stable, reproducible, and interference resistant, and exhibits a fast response time. The developed glucose biosensor has a great potential for detection of mercury with several advantages such as being inexpensive, requiring minimum hardware and being suitable for unskilled users.

  16. High glucose, glucose fluctuation and carbonyl stress enhance brain microvascular endothelial barrier dysfunction: Implications for diabetic cerebral microvasculature

    Directory of Open Access Journals (Sweden)

    Wei Li

    2015-08-01

    Full Text Available We previously demonstrated that in normal glucose (5 mM, methylglyoxal (MG, a model of carbonyl stress induced brain microvascular endothelial cell (IHEC dysfunction that was associated with occludin glycation and prevented by N-acetylcysteine (NAC. Herein, we investigated the impact of high glucose and low GSH, conditions that mimicked the diabetic state, on MG-induced IHEC dysfunction. MG-induced loss of transendothelial electrical resistance (TEER was potentiated in IHECs cultured for 7 or 12 days in 25 mM glucose (hyperglycemia; moreover, barrier function remained disrupted 6 h after cell transfer to normal glucose media (acute glycemic fluctuation. Notably, basal occludin glycation was elevated under these glycemic states. TEER loss was exaggerated by inhibition of glutathione (GSH synthesis and abrogated by NAC, which corresponded to GSH decreases and increases, respectively. Significantly, glyoxalase II activity was attenuated in hyperglycemic cells. Moreover, hyperglycemia and GSH inhibition increased MG accumulation, consistent with a compromised capacity for MG elimination. α-Oxoaldehydes (MG plus glyoxal levels were elevated in streptozotocin-induced diabetic rat plasma. Immunohistochemistry revealed a prevalence of MG-positive, but fewer occludin-positive microvessels in the diabetic brain in vivo, and Western analysis confirmed an increase in MG–occludin adducts. These results provide the first evidence that hyperglycemia and acute glucose fluctuation promote MG–occludin formation and exacerbate brain microvascular endothelial dysfunction. Low occludin expression and high glycated-occludin contents in diabetic brain in vivo are factors that would contribute to the dysfunction of the cerebral microvasculature during diabetes.

  17. Inhibition of glucose turnover by 3-bromopyruvate counteracts pancreatic cancer stem cell features and sensitizes cells to gemcitabine

    OpenAIRE

    Isayev, Orkhan; Rausch, Vanessa; Bauer, Nathalie; Liu, Li; Fan, Pei; Zhang, Yiyao; Gladkich, Jury; Nwaeburu, Clifford C.; Mattern, Jürgen; Mollenhauer, Martin; Rückert, Felix; Zach, Sebastian; Haberkorn, Uwe; Gross, Wolfgang; Schönsiegel, Frank

    2014-01-01

    According to the cancer stem cell (CSC) hypothesis, the aggressive growth and early metastasis of pancreatic ductal adenocarcinoma (PDA) is due to the activity of CSCs, which are not targeted by current therapies. Otto Warburg suggested that the growth of cancer cells is driven by a high glucose metabolism. Here, we investigated whether glycolysis inhibition targets CSCs and thus may enhance therapeutic efficacy. Four established and 3 primary PDA cell lines, non-malignant cells, and 3 patien...

  18. Heme oxygenase-1-derived bilirubin protects endothelial cells against high glucose-induced damage.

    Science.gov (United States)

    He, Meihua; Nitti, Mariapaola; Piras, Sabrina; Furfaro, Anna Lisa; Traverso, Nicola; Pronzato, Maria Adelaide; Mann, Giovanni E

    2015-12-01

    Hyperglycemia and diabetes are associated with endothelial cell dysfunction arising from enhanced oxidative injury, leading to the progression of diabetic vascular pathologies. The redox-sensitive transcription factor nuclear factor-E2-related factor 2 (Nrf2) is a master regulator of antioxidant genes, such as heme oxygenase-1 (HO-1), involved in cellular defenses against oxidative stress. We have investigated the pathways involved in high glucose-induced activation of HO-1 in endothelial cells and examined the molecular mechanisms underlying cytoprotection. Elevated d-glucose increased intracellular generation of reactive oxygen species (ROS), leading to nuclear translocation of Nrf2 and HO-1 expression in bovine aortic endothelial cells, with no changes in cell viability. Superoxide scavenging and inhibition of endothelial nitric oxide synthase (eNOS) abrogated upregulation of HO-1 expression by elevated glucose. Inhibition of HO-1 increased the sensitivity of endothelial cells to high glucose-mediated damage, while addition of bilirubin restored cell viability. Our findings establish that exposure of endothelial cells to high glucose leads to activation of endogenous antioxidant defense genes via the Nrf2/ARE pathway. Upregulation of HO-1 provides cytoprotection against high glucose-induced oxidative stress through the antioxidant properties of bilirubin. Modulation of the Nrf2 pathway in the early stages of diabetes may thus protect against sustained damage by hyperglycemia during progression of the disease.

  19. Protective effects of marein on high glucose-induced glucose metabolic disorder in HepG2 cells.

    Science.gov (United States)

    Jiang, Baoping; Le, Liang; Zhai, Wei; Wan, Wenting; Hu, Keping; Yong, Peng; He, Chunnian; Xu, Lijia; Xiao, Peigen

    2016-08-15

    Our previous study has shown that Coreopsis tinctoria increases insulin sensitivity and regulates hepatic metabolism in high-fat diet (HFD)-induced insulin resistance rats. However, it is unclear whether or not marein, a major compound of C. tinctoria, could improve insulin resistance. Here we investigate the effect and mechanism of action of marein on improving insulin resistance in HepG2 cells. We investigated the protective effects of marein in high glucose-induced human liver carcinoma cell HepG2. In kinase inhibitor studies, genistein, LY294002, STO-609 and compound C were added to HepG2 cells 1h before the addition of marein. Transfection with siRNA was used to knock down LKB1, and 2-(N-(7-nitrobenz-2-oxa-1, 3-diazol-4-yl) amino)-2-deoxyglucose (2-NBDG), an effective tracer, was used to detect glucose uptake. The results showed for the first time that marein significantly stimulates the phosphorylation of AMP-activated protein kinase (AMPK) and the Akt substrate of 160kDa (AS160) and enhanced the translocation of glucose transporter 1 (GLUT1) to the plasma membrane. Further study indicated that genistein (an insulin receptor tyrosine kinase inhibitor) altered the effect of marein on glucose uptake, and both LY294002 (a phosphatidylinositol 3-kinase inhibitor) and compound C (an AMP-activated protein kinase inhibitor) significantly decreased marein-stimulated 2-NBDG uptake. Additionally, marein-stimulated glucose uptake was blocked in the presence of STO-609, a CaMKK inhibitor; however, marein-stimulated AMPK phosphorylation was not blocked by LKB1 siRNA in HepG2 cells. Marein also inhibited the phosphorylation of insulin receptor substrate (IRS-1) at Ser 612, but inhibited GSK-3β phosphorylation and increased glycogen synthesis. Moreover, marein significantly decreased the expression levels of FoxO1, G6Pase and PEPCK. Consequently, marein improved insulin resistance induced by high glucose in HepG2 cells through CaMKK/AMPK/GLUT1 to promote glucose uptake

  20. High glucose repatterns human podocyte energy metabolism during differentiation and diabetic nephropathy

    Science.gov (United States)

    Imasawa, Toshiyuki; Obre, Emilie; Bellance, Nadège; Lavie, Julie; Imasawa, Tomoko; Rigothier, Claire; Delmas, Yahsou; Combe, Christian; Lacombe, Didier; Benard, Giovanni; Claverol, Stéphane; Bonneu, Marc; Rossignol, Rodrigue

    2017-01-01

    Podocytes play a key role in diabetic nephropathy pathogenesis, but alteration of their metabolism remains unknown in human kidney. By using a conditionally differentiating human podocyte cell line, we addressed the functional and molecular changes in podocyte energetics during in vitro development or under high glucose conditions. In 5 mM glucose medium, we observed a stepwise activation of oxidative metabolism during cell differentiation that was characterized by peroxisome proliferator-activated receptor-γ coactivator 1α (PGC-1α)–dependent stimulation of mitochondrial biogenesis and function, with concomitant reduction of the glycolytic enzyme content. Conversely, when podocytes were cultured in high glucose (20 mM), stepwise oxidative phosphorylation biogenesis was aborted, and a glycolytic switch occurred, with consecutive lactic acidosis. Expression of the master regulators of oxidative metabolism transcription factor A mitochondrial, PGC-1α, AMPK, and serine–threonine liver kinase B1 was altered by high glucose, as well as their downstream signaling networks. Focused transcriptomics revealed that myocyte-specific enhancer factor 2C (MEF2C) and myogenic factor 5 (MYF5) expression was inhibited by high glucose levels, and endoribonuclease-prepared small interfering RNA–mediated combined inhibition of those transcription factors phenocopied the glycolytic shift that was observed in high glucose conditions. Accordingly, a reduced expression of MEF2C, MYF5, and PGC-1α was found in kidney tissue sections that were obtained from patients with diabetic nephropathy. These findings obtained in human samples demonstrate that MEF2C-MYF5–dependent bioenergetic dedifferentiation occurs in podocytes that are confronted with a high-glucose milieu.—Imasawa, T., Obre, E., Bellance, N., Lavie, J., Imasawa, T., Rigothier, C., Delmas, Y., Combe, C., Lacombe, D., Benard, G., Claverol, S., Bonneu, M., Rossignol, R. High glucose repatterns human podocyte energy

  1. Punicalagin exerts protective effect against high glucose-induced cellular stress and neural tube defects.

    Science.gov (United States)

    Zhong, Jianxiang; Reece, E Albert; Yang, Peixin

    2015-11-13

    Maternal diabetes-induced birth defects remain a significant health problem. Studying the effect of natural compounds with antioxidant properties and minimal toxicities on diabetic embryopathy may lead to the development of new and safe dietary supplements. Punicalagin is a primary polyphenol found in pomegranate juice, which possesses antioxidant, anti-inflammatory and anti-tumorigenic properties, suggesting a protective effect of punicalagin on diabetic embryopathy. Here, we examined whether punicalagin could reduce high glucose-induced neural tube defects (NTDs), and if this rescue occurs through blockage of cellular stress and caspase activation. Embryonic day 8.5 (E8.5) mouse embryos were cultured for 24 or 36 h with normal (5 mM) glucose or high glucose (16.7 mM), in presence or absence of 10 or 20 μM punicalagin. 10 μM punicalagin slightly reduced NTD formation under high glucose conditions; however, 20 μM punicalagin significantly inhibited high glucose-induced NTD formation. Punicalagin suppressed high glucose-induced lipid peroxidation marker 4-hydroxynonenal, nitrotyrosine-modified proteins, and lipid peroxides. Moreover, punicalagin abrogated endoplasmic reticulum stress by inhibiting phosphorylated protein kinase ribonucleic acid (RNA)-like ER kinase (p-PERK), phosphorylated inositol-requiring protein-1α (p-IRE1α), phosphorylated eukaryotic initiation factor 2α (p-eIF2α), C/EBP-homologous protein (CHOP), binding immunoglobulin protein (BiP) and x-box binding protein 1 (XBP1) mRNA splicing. Additionally, punicalagin suppressed high glucose-induced caspase 3 and caspase 8 cleavage. Punicalagin reduces high glucose-induced NTD formation by blocking cellular stress and caspase activation. These observations suggest punicalagin supplements could mitigate the teratogenic effects of hyperglycemia in the developing embryo, and possibly prevent diabetes-induced NTDs.

  2. Novel benzoxazine-based aglycones block glucose uptake in vivo by inhibiting glycosidases.

    Directory of Open Access Journals (Sweden)

    Hanumantharayappa Bharathkumar

    Full Text Available Glycoside hydrolases catalyze the selective hydrolysis of glycosidic bonds in oligosaccharides, polysaccharides, and their conjugates. β-glucosidases occur in all domains of living organisms and constitute a major group among glycoside hydrolases. On the other hand, the benzoxazinoids occur in living systems and act as stable β-glucosides, such as 2-(2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3(4H-one-β-D-gluco-pyranose, which hydrolyse to an aglycone DIMBOA. Here, we synthesized the library of novel 1,3-benzoxazine scaffold based aglycones by using 2-aminobenzyl alcohols and aldehydes from one-pot reaction in a chloroacetic acid catalytic system via aerobic oxidative synthesis. Among the synthesized benzoxazines, 4-(7-chloro-2,4-dihydro-1H-benzo[d][1,3]oxazin-2-ylphenol (compound 7 exhibit significant inhibition towards glucosidase compared to acarbose, with a IC50 value of 11.5 µM. Based upon results generated by in silico target prediction algorithms (Naïve Bayesian classifier, these aglycones potentially target the additional sodium/glucose cotransporter 1 (where a log likelihood score of 2.70 was observed. Furthermore, the in vitro glucosidase activity was correlated with the in silico docking results, with a high docking score for the aglycones towards the substrate binding site of glycosidase. Evidently, the in vitro and in vivo experiments clearly suggest an anti-hyperglycemic effect via glucose uptake inhibition by 4-(7-chloro-2,4-dihydro-1H-benzo[d][1,3]oxazin-2-ylphenol in the starved rat model. These synthetic aglycones could constitute a novel pharmacological approach for the treatment, or re-enforcement of existing treatments, of type 2 diabetes and associated secondary complications.

  3. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport

    Science.gov (United States)

    Naftalin, Richard J; Cunningham, Philip; Afzal-Ahmed, Iram

    2004-01-01

    Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide galanin in human erythrocytes in vitro. The potencies of nootropic drugs in opposing scopolamine-induced memory loss correlate with their potencies in antagonising pentobarbital inhibition of erythrocyte glucose transport in vitro (PPiracetam and TRH have no direct effects on net glucose transport, but competitively antagonise hypnotic drug inhibition of glucose transport. Other nootropics, like aniracetam and levetiracetam, while antagonising pentobarbital action, also inhibit glucose transport. Analeptics like bemigride and methamphetamine are more potent inhibitors of glucose transport than antagonists of hypnotic action on glucose transport. There are similarities between amino-acid sequences in human glucose transport protein isoform 1 (GLUT1) and the benzodiazepine-binding domains of GABAA (gamma amino butyric acid) receptor subunits. Mapped on a 3D template of GLUT1, these homologies suggest that the site of diazepam and piracetam interaction is a pocket outside the central hydrophilic pore region. Nootropic pyrrolidone antagonism of hypnotic drug inhibition of glucose transport in vitro may be an analogue of TRH antagonism of galanin-induced narcosis. PMID:15148255

  4. Accuracy of Handheld Blood Glucose Meters at High Altitude

    NARCIS (Netherlands)

    de Mol, Pieter; Krabbe, Hans G.; de Vries, Suzanna T.; Fokkert, Marion J.; Dikkeschei, Bert D.; Rienks, Rienk; Bilo, Karin M.; Bilo, Henk J. G.

    2010-01-01

    Background: Due to increasing numbers of people with diabetes taking part in extreme sports (e. g., high-altitude trekking), reliable handheld blood glucose meters (BGMs) are necessary. Accurate blood glucose measurement under extreme conditions is paramount for safe recreation at altitude. Prior st

  5. Inhibition of stress induced hyperglucagonemia by administration of glucose in normal and alloxan-diabetic rat.

    Science.gov (United States)

    Klimes, I; Jurcovicová, J; Németh, S; Jezová, D; Vigas, M

    1981-01-01

    The increase in plasma pancreatic glucagon which is known to occur under several stress conditions was confirmed in fed and 18 h prefasted rats subjected to a low, "stress producing" dose of the Noble-collip drum procedure (400 revolutions per 400 s). A single dose of exogenous glucose ( 1 g kg-1) injected 3 min and 20 s before stress into the jugular vein of intact fasted or fed animals anesthetized with pentobarbital 930 mg kg-1) completely abolished their hyperglucagonemic response in stress. In alloxan-diabetic hyperglycemic rats the stress-hyperglucagonemia was exaggerated, but was also suppressible by exogenous glucose. It was concluded that: 1. the stress induced hyperglucagonemic response of both intact and alloxan-diabetic rats was completely suppressible by administration of i.v. bolus of exogenous glucose; 2. the site inhibiting effect of glucose might be located either at the level of A cell or at the level of "'glucoreceptors" in hypothalamus.

  6. LP-925219 maximizes urinary glucose excretion in mice by inhibiting both renal SGLT1 and SGLT2

    OpenAIRE

    Powell, David R.; Smith, Melinda G; Doree, Deon D; Harris, Angela L; Xiong, Wendy W; Mseeh, Faika; Wilson, Alan; Gopinathan, Suma; Diaz, Damaris; Goodwin, Nicole C.; Harrison, Bryce; Strobel, Eric; Rawlins, David B.; Carson, Ken; Zambrowicz, Brian

    2015-01-01

    Sodium-glucose cotransporter 2 (SGLT2) inhibitors are a new class of oral anti-diabetic agents that improve glycemic control by inhibiting SGLT2-mediated renal glucose reabsorption. Currently available agents increase urinary glucose excretion (UGE) to 50% of filtered glucose when SGLT2 is completely inhibited. This led us to test whether LP-925219, a small molecule dual SGLT1/SGLT2 inhibitor, increases UGE to maximal values in wild-type (WT) mice. We first tested LP-925219 inhibition of gluc...

  7. Effect of heparin on high glucose induced proliferation and expression of matrix metalloproteinases in normal human mesangial cells

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qiao-ling; Arima Terukatsu; Yasumoto Yuichiro; Tsukamoto Masatoshi; Nozaki Tsuyoshi; Sogabe Atsushi; Harada Kouji; ZHANG Yi-xiang; LIN Xiao-yan; ZHANG Yang-de

    2005-01-01

    Background The pathogenesis of diabetic nephropathy (DN) is a complex pathophysiological process.Its precise mechanism is not fully known. In recent years it has been recognized that synthesis of various extracelluar matrix (ECM) components may increase, and that degradation of ECM may decrease in DN. It was reported heparin could inhibit mesangial cells proliferation in vitro. The main aim of this study is to explore whether heparin inhibits proliferation of mesangial cells grown in high glucose concentration and to measure the effect of heparin on matrix metalloproteinases (MMPs) expression in mesangial cells. Methods The medium contained either low glucose (5 mmol/L) or high glucose (25 mmol/L). The concentrations of heparin in the culture medium were 0, 25, 50,100, 200 or 400 μg/mL. A metabolic (WST-1) assay was used to measure mesangial cell proliferation and Western blot analysis was used to measure MMPs expression of mesangial cells. Results Normal human mesangial cell (NHMC) proliferation was higher in high glucose (HG) medium than in low glucose (LG) medium. They showed a 1.93 fold expansion after 72 h in high glucose in contrast to a 1.63 fold expansion in low glucose. In the presence of heparin, mesangial cells proliferation was inhibited, which was more obvious at high glucose concentrations than at low glucose concentrations. In high glucose, with heparin concentration of 50, 100, 200 and 400 μg/mL, the mesangial cells showed a 0. 61 fold, 0.52 fold, 0.52 fold and 0.41 fold reductions in cell number compared to cells grown without heparin. In low glucose, only concentrations of 200 μg/mL and 400 μg/mL showed reduction in cell number, namely 0.54 fold and 0.45 fold, when compared to cells grown without heparin. In Western blot analysis,MMP1, MMP2, MMP3 and MMP9 was expressed by mesangial cells expressed in both high and low glucose concentrations, which was more prominent in high glucose medium. Incubation of heparin further increased expression of

  8. Plin2 inhibits cellular glucose uptake through interactions with SNAP23, a SNARE complex protein.

    Directory of Open Access Journals (Sweden)

    Subramanian Senthivinayagam

    Full Text Available Although a link between excess lipid storage and aberrant glucose metabolism has been recognized for many years, little is known what role lipid storage droplets and associated proteins such as Plin2 play in managing cellular glucose levels. To address this issue, the influence of Plin2 on glucose uptake was examined using 2-NBD-Glucose and [(3H]-2-deoxyglucose to show that insulin-mediated glucose uptake was decreased 1.7- and 1.8-fold, respectively in L cell fibroblasts overexpressing Plin2. Conversely, suppression of Plin2 levels by RNAi-mediated knockdown increased 2-NBD-Glucose uptake several fold in transfected L cells and differentiated 3T3-L1 cells. The effect of Plin2 expression on proteins involved in glucose uptake and transport was also examined. Expression of the SNARE protein SNAP23 was increased 1.6-fold while levels of syntaxin-5 were decreased 1.7-fold in Plin2 overexpression cells with no significant changes observed in lipid droplet associated proteins Plin1 or FSP27 or with the insulin receptor, GLUT1, or VAMP4. FRET experiments revealed a close proximity of Plin2 to SNAP23 on lipid droplets to within an intramolecular distance of 51 Å. The extent of targeting of SNAP23 to lipid droplets was determined by co-localization and co-immunoprecipitation experiments to show increased partitioning of SNAP23 to lipid droplets when Plin2 was overexpressed. Taken together, these results suggest that Plin2 inhibits glucose uptake by interacting with, and regulating cellular targeting of SNAP23 to lipid droplets. In summary, the current study for the first time provides direct evidence for the role of Plin2 in mediating cellular glucose uptake.

  9. Intermittent High Glucose Enhances Apoptosis in INS-1 Cells

    Directory of Open Access Journals (Sweden)

    Xiao-li Shi

    2011-01-01

    Full Text Available To investigate the effect of intermittent high glucose (IHG and sustained high glucose (SHG on inducing β-cell apoptosis and the potential involved mechanisms, INS-1 beta cells were incubated for 72 h in the medium containing different glucose concentrations: control (5.5 mmol/L, SHG (33.3 mmol/L, and IHG (5.5 mmol/L and 33.3 mmol/L glucose alternating every 12 h. Cell viability, apoptosis rate, and oxidative-stress markers were determined. The results showed that the apoptosis induced by IHG was more obvious than that by SHG. Simultaneously, the intracellular level of oxidative stress was more significantly increased in INS-1 cells exposed to IHG. These findings suggest that intermittent high glucose could be more deleterious to β-cell than a constant high concentration of glucose, this may be due to the aggravation of oxidative stress triggered by intermittent high glucose.

  10. Disruption of microtubules in rat skeletal muscle does not inhibit insulin- or contraction-stimulated glucose transport

    DEFF Research Database (Denmark)

    Ai, Hua; Ralston, Evelyn; Lauritzen, Hans P M M

    2003-01-01

    or epitrochlearis muscles. In contrast, nocodazole, another microtubule-disrupting drug, rapidly and dose dependently blocked insulin- and contraction-stimulated glucose transport. A similar discrepancy between colchicine and nocodazole was also found in their ability to block glucose transport in muscle giant...... "ghost" vesicles. This suggests that the ability of insulin and contractions to stimulate glucose transport in muscle does not require an intact microtubule network and that nocodazole inhibits glucose transport independently of its microtubule-disrupting effect....

  11. Aldolase B knockdown prevents high glucose-induced methylglyoxal overproduction and cellular dysfunction in endothelial cells.

    Directory of Open Access Journals (Sweden)

    Jianghai Liu

    Full Text Available We used cultured endothelial cells as a model to examine whether up-regulation of aldolase B and enhanced methylglyoxal (MG formation play an important role in high glucose-induced overproduction of advanced glycosylation endproducts (AGEs, oxidative stress and cellular dysfunction. High glucose (25 mM incubation up-regulated mRNA levels of aldose reductase (an enzyme converting glucose to fructose and aldolase B (a key enzyme that catalyzes MG formation from fructose and enhanced MG formation in human umbilical vein endothelial cells (HUVECs and HUVEC-derived EA. hy926 cells. High glucose-increased MG production in EA. hy926 cells was completely prevented by siRNA knockdown of aldolase B, but unaffected by siRNA knockdown of aldolase A, an enzyme responsible for MG formation during glycolysis. In addition, inhibition of cytochrome P450 2E1 or semicarbazide-sensitive amine oxidase which produces MG during the metabolism of lipid and proteins, respectively, did not alter MG production. Both high glucose (25 mM and MG (30, 100 µM increased the formation of N(ε-carboxyethyl-lysine (CEL, a MG-induced AGE, oxidative stress (determined by the generation of oxidized DCF, H(2O(2, protein carbonyls and 8-oxo-dG, O-GlcNAc modification (product of the hexosamine pathway, membrane protein kinase C activity and nuclear translocation of NF-κB in EA. hy926 cells. However, the above metabolic and signaling alterations induced by high glucose were completely prevented by knockdown of aldolase B and partially by application of aminoguanidine (a MG scavenger or alagebrium (an AGEs breaker. In conclusion, efficient inhibition of aldolase B can prevent high glucose-induced overproduction of MG and related cellular dysfunction in endothelial cells.

  12. Anthrax lethal toxin suppresses high glucose induced VEGF over secretion through a post-translational mechanism

    Institute of Scientific and Technical Information of China (English)

    Wei-Wei; Zhang; Xin; Wang; Ping; Xie; Song-Tao; Yuan; Qing-Huai; Liu

    2015-01-01

    AIM: To prove anthrax lethal toxin(Le Tx) blocks the mitogen activated protein kinases(MAPKs) activation by degrading the MAPK/ERK kinases(MEKs) to suppress vascular endothelial growth factor(VEGF) secretion.METHODS: Human adult retinal pigmented epithelium(ARPE) cells were cultured and treated with normal glucose, high glucose or high glucose with Le Tx for additional 24, 48 or 72 h for viable cell count. Total RNA from the ARPE was isolated for reverse transcription polymerase chain reaction(RT-PCR). The conditioned medium of ARPE cells treated in different group for 48 h was filtered and diluted to detect the concentration of VEGF by enzyme-linked immunosorbant assays.Evaluate the role of MEK/MAPK pathway in the secretion of VEGF by immunoblotting. RESULTS: In this study, we proved high glucose induced activation of the MAPK extracellular signal-regulated kinase(ERK1/2) and p38 in the ARPE cell line was blocked by anthrax Le Tx. Le Tx also inhibited high glucose induced ARPE cell over proliferation.CONCLUSION: Le Tx suppressed high glucose induced VEGF over secretion in the ARPE cells, mainly through a post-translational mechanism.

  13. Modification of cellulose for high glucose generation.

    Science.gov (United States)

    Jiang, Xue; Gu, Jian; Tian, Xiuzhi; Li, Yali; Huang, Dan

    2012-01-01

    The influence of introduction of cyanuric chloride on glucose's yield (Y) in acid-catalyzed hydrolysis of microcrystalline cellulose (MCC) has been studied. The content of cyanuric chloride (C) in modified MCCs was determined by X-ray photoelectric spectroscopy. The chemical structures of modified MCCs were analyzed by Fourier transformation-infrared spectroscopy and cross polarization/magic angle spinning (13)C nuclear magnetic resonance. Crystal index (CI) and the ratio (R) representing the sum of content of (1 ̅10) and (110) to that of (200) were calculated based on diffraction intensity in wide angle X-ray diffraction (WAXD). Hydrolysis experiment and WAXD show that Y, CI and R vary with C. The modified MCC containing 3.9 mol% of cyanuric chloride has the highest Y, the highest R and the lowest CI. Variations of CI and R show that the chemical modification changed the proportion of crystal/amorphous and crystal planes, both of which influence glucose's generation in hydrolysis of cellulose.

  14. Oleanolic acid ameliorates high glucose-induced endothelial dysfunction via PPARδ activation

    Science.gov (United States)

    Zhang, Zihui; Jiang, Manli; Xie, Xinya; Yang, Haixia; Wang, Xinfeng; Xiao, Lei; Wang, Nanping

    2017-01-01

    Oleanolic acid (3β-hydroxyolean-12-en-28-oic acid, OA) is a pentacyclic triterpenes widely distributed in food, medicinal plants and nutritional supplements. OA exhibits various pharmacological properties, such as hepatoprotective and anti-tumor effects. In this study, we analyzed the effect of OA on endothelial dysfunction induced by high glucose in human vascular endothelial cells (ECs). Western blotting showed that OA attenuated high glucose-reduced nitric production oxide (NO) as well as Akt-Ser473 and eNOS-Ser1177 phosphorylation in cultured human umbilical vein ECs (HUVECs). Next, luciferase reporter assay showed that OA activated peroxisome proliferators-activated receptor δ (PPARδ) activity. Quantitative reverse transcriptase PCR (qRT-PCR) demonstrated that OA increased the expressions of PPARδ target genes (PDK4, ADRP and ANGPTL4) in ECs. Meanwhile, the induced expressions of PDK4, ADRP and ANGPTL4 by OA were inhibited by GSK0660, a specific antagonist of PPARδ. In addition, inhibition of PPARδ abolished OA-induced the Akt-Ser473 and eNOS-Ser1177 phosphorylation, and NO production. Finally, by using Multi Myograph System, we showed that OA prevented high glucose-impaired vasodilation. This protective effect on vasodilation was inhibited in aortic rings pretreated with GSK0660. Collectively, we demonstrated that OA improved high glucose-impaired endothelial function via a PPARδ-mediated mechanism and through eNOS/Akt/NO pathway. PMID:28067284

  15. Glucose level regulation via integral high-order sliding modes.

    Science.gov (United States)

    Dorel, Lela

    2011-04-01

    Diabetes is a condition in which the body either does not produce enough insulin, or does not properly respond to it. This causes the glucose level in blood to increase. An algorithm based on Integral High-Order Sliding Mode technique is proposed, which keeps the normal blood glucose level automatically releasing insulin into the blood. The system is highly insensitive to inevitable parametric and model uncertainties, measurement noises and small delays.

  16. Rapid amperometric detection of trace metals by inhibition of an ultrathin polypyrrole-based glucose biosensor.

    Science.gov (United States)

    Ayenimo, Joseph G; Adeloju, Samuel B

    2016-02-01

    A sensitive and reliable inhibitive amperometric glucose biosensor is described for rapid trace metal determination. The biosensor utilises a conductive ultrathin (55 nm thick) polypyrrole (PPy) film for entrapment of glucose oxidase (GOx) to permit rapid inhibition of GOx activity in the ultrathin film upon exposure to trace metals, resulting in reduced glucose amperometric response. The biosensor demonstrates a relatively fast response time of 20s and does not require incubation. Furthermore, a complete recovery of GOx activity in the ultrathin PPy-GOx biosensor is quickly achieved by washing in 2mM EDTA for only 10s. The minimum detectable concentrations achieved with the biosensor for Hg(2+), Cu(2+), Pb(2+) and Cd(2+) by inhibitive amperometric detection are 0.48, 1.5, 1.6 and 4.0 µM, respectively. Also, suitable linear concentration ranges were achieved from 0.48-3.3 µM for Hg(2+), 1.5-10 µM for Cu(2+), 1.6-7.7 µM for Pb(2+) and 4-26 µM for Cd(2+). The use of Dixon and Cornish-Bowden plots revealed that the suppressive effects observed with Hg(2+) and Cu(2+) were via non-competitive inhibition, while those of Pb(2+) and Cd(2+) were due to mixed and competitive inhibition. The stronger inhibition exhibited by the trace metals on GOx activity in the ultrathin PPy-GOx film was also confirmed by the low inhibition constant obtained from this analysis. The biosensor was successfully applied to the determination of trace metals in tap water samples.

  17. Bis-Pyrano Prenyl Isoflavone Improves Glucose Homeostasis by Inhibiting Dipeptidyl Peptidase-4 in Hyperglycemic Rats.

    Science.gov (United States)

    Altenhofen, Delsi; da Luz, Gabrielle; Frederico, Marisa Jádna Silva; Venzke, Dalila; Brich, Mayara; Vigil, Silvana; Fröde, Tania Silvia; Linares, Carlos Eduardo Blanco; Pizzolatti, Moacir Geraldo; Silva, Fátima Regina Mena Barreto

    2017-01-01

    Isoflavones widely distributed in plants prevent diabetes. This study investigated the in vivo and in vitro effect of 3',4'-dihydroxy-6″,6″,6″',6″'-tetramethylbis(pyrano[2″,3″:5,6::2″',3″':7,8]isoflavone (bis-pyrano prenyl isoflavone) on glucose homeostasis in hyperglycemic rats. The ethyl acetate fraction from aerial parts of Polygala molluginifolia that contain isoflavones was assayed on glucose tolerance, on in vitro maltase activity and on protein glycation. The isoflavone bis-pyrano prenyl isolated from this fraction was investigated on glucose homeostasis. The in vivo action of the isoflavone exhibits an anti-hyperglycemic effect by improving glucose tolerance, augmenting the liver glycogen, inhibiting maltase activity, and stimulating glucagon-like peptide-1 (GLP-1) and insulin secretion. The in vitro isoflavone inhibits dipeptidyl peptidase-4 (DPP-4) activity since the glucose tolerance was improved in the presence of the isoflavone as much as sitagliptin, an inhibitor of DPP-4. However, the co-incubation with isoflavone and sitagliptin exhibited an additive anti-hyperglycemic action. The isoflavone increased the GLP-1 faster than the positive hyperglycemic group, which shows that the intestine is a potential target. Thus, to clarify the main site of action in which isoflavone improves glucose balance, the in vitro mechanism of action of this compound was tested in intestine using calcium influx as a trigger for the signal pathways for GLP-1 secretion. The isoflavone stimulates calcium influx in intestine and its mechanism involves voltage-dependent calcium channels, phospholipase C, protein kinase C, and stored calcium contributing for GLP-1 secretion. In conclusion, the isoflavone regulates glycaemia by acting mainly in a serum target, the DPP-4 inhibitor. Furthermore, the long-term effect of isoflavone prevents protein glycation. J. Cell. Biochem. 118: 92-103, 2017. © 2016 Wiley Periodicals, Inc.

  18. High glucose augments stress-induced apoptosis in endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Wenwen Zhong; Yang Liu; Hui Tian

    2009-01-01

    Hyperglycemia has been identified as one of the important factors involved in the microvascular complications of diabetes, and has been related to increased cardiovascular mortality. Endothelial damage and dysfunction result from diabetes; therefore, the aim of this study was to determine the response of endothelial cells to stressful stimuli, modelled in normal and high glucose concentrations in vitro. Eahy 926 endothelial cells were cultured in 5 mmol/L or 30 mmol/L glucose conditions for a 24 hour period and oxidative stress was induced by exposure to hydrogen peroxide (H2O2) or tumour necrosis factor- α (TNF- α ), following which the protective effect of the glucocorticoid dexamethasone was assessed. Apoptosis, necrosis and cell viability were determined using an ELISA for DNA fragmentation, an enzymatic lactate dehydrogenase assay and an MTT assay, respectively. High glucose significantly increased the susceptibility of Eahy 926 cells to apoptosis in the presence of 500 μmol/L H2O2, above that induced in normal glucose (P<0.02). A reduction of H2O2- and TNF- α -induced apoptosis occurred in both high and low glucose after treatment with dexametha-sone (P<0.05). Conclusion high glucose is effective in significantly augmenting stress caused by H2O2, but not in causing stress alone. These findings suggest a mechanism by which short term hyperglycemia may facilitate and augment endothelial damage.

  19. Quercetin alleviates high glucose-induced Schwann cell damage by autophagy

    Institute of Scientific and Technical Information of China (English)

    Ling Qu; Xiaochun Liang; Bei Gu; Wei Liu

    2014-01-01

    Quercetin can reverse high glucose-induced inhibition of neural cell proliferation, and therefore may have a neuroprotective effect in diabetic peripheral neuropathy. It is dififcult to obtain pri-mary Schwann cells and RSC96 cells could replace primary Schwann cells in studies of the role of autophagy in the mechanism underlying diabetic peripheral neuropathy. Here, we show that under high glucose conditions, there are fewer autophagosomes in immortalized rat RSC96 cells and primary rat Schwann cells than under control conditions, the proliferative activity of both cell types is signiifcantly impaired, and the expression of Beclin-1 and LC3, the molecular mark-ers for autophagy, is signiifcantly lower. After intervention with quercetin, the autophagic and proliferative activity of both cell types is rescued. These results suggest that quercetin can allevi-ate high glucose-induced damage to Schwann cells by autophagy.

  20. Determination of trace mercury in compost extract by inhibition based glucose oxidase biosensor

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-xiao; XU Xiang-min; TANG Lin; ZENG Guang-ming

    2009-01-01

    A novel inhibition based biosensor of glucose oxidase(GOx) for environmental mercury detection was developed. An electropolymerized aniline membrane was prepared on a platinum electrode containing ferrocene as electron transfer mediator, on which GOx was cross-linked by glutaraldehyde. The response of the sensor was based on the current reduction in the electrochemical system by inhibition of mercury against GOx electrode. The detection limit of the inhibition-based sensor for mercury is 0.49 μg/L, and the linear response ranges are 0.49-783.21 μg/L and 783.21 μg/L-25.55 mg/L. The GOx membrane can be completely reactivated after inhibition, and remains 70% of the activity in more than one month. The sensor was used for mercury determination in compost extract with good results.

  1. Physicochemical studies of glucose, gellan gum, and hydroxypropyl cellulose--inhibition of cast iron corrosion.

    Science.gov (United States)

    Rajeswari, Velayutham; Kesavan, Devarayan; Gopiraman, Mayakrishnan; Viswanathamurthi, Periasamy

    2013-06-05

    Glucose, gellan gum, and hydroxypropyl cellulose were studied against the acid corrosion of cast iron by means of weight loss, potentiodynamic polarization, and AC impedance spectroscopy techniques. The inhibition efficiency was found to increase with increasing concentration of the inhibitors. The effect of immersion time and temperature were also studied. The addition of potassium iodide to the corrosion-inhibition system showed both antagonism and synergism toward inhibition efficiency. Polarization studies revealed the mixed-type inhibiting nature of the carbohydrates. The adsorption of inhibitors on the cast iron surface obeys Langmuir adsorption isotherm model, both in presence and absence of KI. Physical interaction between the inhibitor molecules and the iron surface was suggested by the thermochemical parameters, rather than chemical interaction.

  2. Inhibition of renal glucose reabsorption as a novel treatment for diabetes patients

    Directory of Open Access Journals (Sweden)

    Eugenio Cersosimo

    2014-03-01

    Full Text Available The importance of the kidney in glucose homeostasis has been recognized for many years. Recent observations indicating a greater role of renal glucose metabolism in various physiologic and pathologic conditions have rekindled the interest in renal glucose handling as a potential target for the treatment of diabetes. The enormous capacity of the proximal tubular cells to reabsorb the filtered glucose load entirely, utilizing the sodium-glucose co-transporter system (primarily SGLT-2, became the focus of attention. Original studies conducted in experimental animals with the nonspecific SGLT inhibitor phlorizin showed that hyperglycemia after pancreatectomy decreased as a result of forced glycosuria. Subsequently, several compounds with more selective SGLT-2 inhibition properties (“second-generation” were developed. Some agents made it into pre-clinical and clinical trials and a few have already been approved for commercial use in the treatment of type 2 diabetes. In general, a 6-month period of therapy with SGLT-2 inhibitors is followed by a mean urinary glucose excretion rate of ~80 g/day accompanied by a decline in fasting and postprandial glucose with average decreases in HgA1C ~1.0%. Concomitant body weight loss and a mild but consistent drop in blood pressure also have been reported. In contrast, transient polyuria, thirst with dehydration and occasional hypotension have been described early in the treatment. In addition, a significant increase in the occurrence of uro-genital infections, particularly in women has been documented with the use of SGLT-2 inhibitors. Conclusion: Although long-term cardiovascular, renal and bone/mineral effects are unknown SGLT-2 inhibitors, if used with caution and in the proper patient provide a unique insulin-independent therapeutic option in the management of obese type 2 diabetes patients.

  3. Effective Control of Postprandial Glucose Level through Inhibition of Intestinal Alpha Glucosidase by Cymbopogon martinii (Roxb.

    Directory of Open Access Journals (Sweden)

    Varsha Ghadyale

    2012-01-01

    Full Text Available Inhibition of intestinal alpha glucosidase plays a major role in preventing rise in postprandial glucose level in diabetics. Cymbopogon martinii (CM (family Poaceae is used in traditional Indian medicine in treatment of diabetes mellitus. The alpha glucosidase inhibitory action of the plant is studied. The active component was separated using hot water extraction of the whole plant powder, differential solvent extraction, and silica gel column chromatography. The 30 : 70 toluene : ethyl acetate fraction showed optimum activity. The silica gel chromatography fraction demonstrated 98, 98, and 68% inhibition for starch, maltose, and sucrose, respectively, at 5 mg/kg body weight of rats. Intestinal absorption studies using noneverted intestinal sacs, as well as in vivo studies in streptozotocin-induced diabetic rats using oral glucose tolerance with maltose and sucrose load, revealed better inhibition of alpha glucosidase as compared to acarbose. Kinetic studies using Lineweaver Burk plot showed mixed to noncompetitive type of inhibition by CM. In vivo studies with maltose load of 2 mg and 3 mg/gm body weight showed a noncompetitive pattern of inhibition at 5 mg/kg body weight of CM as against 60 mg/kg body weight of acarbose. Thus CM is more effective alpha glucosidase inhibitor and at lower concentration than acarbose.

  4. Inhibition of Rhizomucor miehei and Candida rugosa lipases by D-glucose in esterification between L-alanine and D-glucose.

    Science.gov (United States)

    Somashekar, Bhandya R; Lohith, Kenchaiah; Manohar, Balaraman; Divakar, Soundar

    2007-02-01

    A detailed kinetic study of the esterification of D-glucose with L-alanine catalyzed by lipases from Rhizomucor miehei (RML) and Candida rugosa (CRL) showed that both lipases follow the Ping-Pong Bi-Bi mechanism, in which L-alanine and D-glucose bind in subsequent steps releasing water and L-alanyl-D-glucose, with competitive substrate inhibition by D-glucose at higher concentrations leading to the formation of dead-end lipase.D-glucose complexes. An attempt to obtain the best fit of this kinetic model through curve fitting yielded good approximates of the apparent values of four important kinetic parameters: for RML-k(cat)=0.29+/-0.028x10(-3) M h(-1) mg(-1), K(m L-alanine)= 4.9+/-0.51x10(-3) M, K(m D-glucose)=0.21+/-0.018x10(-3) M, and K(i D-glucose)=1.76+/-0.19x10(-3) M; for CRL-k(cat)= 0.75+/-0.08x10(-3) M h(-1) mg(-1), K(m L-alanine)=56.2+/-5.7x10(-3) M, K(m D-glucose)=16.2+/-1.8x10(-3) M, and K(i D-glucose) =21.0+/-1.9x10(-3) M.

  5. The effect of DPP-4 inhibition with sitagliptin on incretin secretion and on fasting and postprandial glucose turnover in subjects with impaired fasting glucose

    DEFF Research Database (Denmark)

    Bock, Gerlies; Man, Chiara Dalla; Micheletto, Francesco

    2010-01-01

    Abstract Objective: Low Glucagon-like Peptide-1 (GLP-1) concentrations have been observed in impaired fasting glucose (IFG). It is uncertain if these abnormalities contribute directly to the pathogenesis of IFG and impaired glucose tolerance. Dipeptidyl peptidase-4 (DPP-4) inhibitors raise incretin...... period, the mixed meal was repeated. Results: As expected, subjects with IFG who received placebo did not experience any change in glucose concentrations. Despite raising intact GLP-1 concentrations, treatment with sitagliptin did not alter either fasting or postprandial glucose, insulin or C....... Conclusions: DPP-4 inhibition did not alter fasting or postprandial glucose turnover in people with IFG. Low incretin concentrations are unlikely to be involved in the pathogenesis of IFG....

  6. Cordyceps sinensis Oral Liquid Inhibits Damage Induced by Oxygen and Glucose Deprivation in SH-SY5Y Cells.

    Science.gov (United States)

    Zou, Ying-Xin; Liu, Yu-Xiang; Ruan, Ming-Hua; Zhou, Yi; Wang, Jia-Chun; Chu, Zhi-Yong

    2016-01-01

    Cordyceps sinensis has been used in traditional Chinese medicine for thousands of years. It has been demonstrated to have a variety of biological activities, and an extract of it has been demonstrated to possess a protective effect in occlusion-induced focal cerebral ischemia of the middle cerebral artery in rats. It could be explored as an agent for treatment of ischemic stroke, and the mechanisms need to be studied further. The study intended to investigate the protective effects of the Cordyceps sinensis oral liquid (CSOL) against damage induced by oxygen and glucose deprivation (OGD) in SH-SY5Y cells. DESIGN • The research team designed an in vitro study. The study occurred at the Naval Medical Research Institute in Shanghai, China. SH-SY5Y cells were exposed to CSOL in doses of 0.01, 0.03, 0.10, 0.30, and 1.00 mg/mL, creating 5 intervention groups. The OGD condition was induced by transfer of the cells from high-glucose Dulbecco's Modified Eagle's medium (DMEM) in a box gassed with air containing 5% CO2 to glucose-free DMEM in a box gassed with 94% N2, 5% CO2, and 1% O2. Like the cells for the interventions groups, the cells for a model group were cultured with high-glucose DMEM and were transferred to the OGD, but they received no dose of COSL. Cells in a control group were cultured with high-glucose DMEM, were not transferred to the OGD condition, and did not receive any dose of COSL. Cell viability was assayed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) method. The apoptosis and the mitochondrial membrane potential (MMP) were detected by flow cytometry, and the protein expression of caspase-3 was observed by western blot. After exposure to OGD, the cell viability of cells treated with 0.01, 0.03, 0.10, 0.30, and 1.00 mg/mL of CSOL increased in a dose-effect relationship. Compared with the cells in the model group, the treatment of CSOL at all the experimental concentrations significantly inhibited both the cell apoptosis

  7. High glucose-boosted inflammatory responses to lipopolysaccharide are suppressed by statin.

    Science.gov (United States)

    Nareika, A; Maldonado, A; He, L; Game, B A; Slate, E H; Sanders, J J; London, S D; Lopes-Virella, M F; Huang, Y

    2007-02-01

    It has been established that periodontal diseases are more prevalent and of greater severity in diabetic patients than in nondiabetic patients. Recent studies have underscored the role of monocytes and macrophages in periodontal tissue inflammation and destruction in diabetic patients. Although it has been shown that monocytes isolated from diabetic patients produce more inflammatory cytokines and that gingival crevicular fluid collected from diabetic patients contains higher levels of inflammatory cytokines than that obtained from nondiabetic patients, the underlying mechanisms are not well understood. U937 histiocytes cultured in medium containing either normal (5 mM) or high (25 mM) glucose were treated with 100 ng/ml of lipopolysaccharide for 24h. After the treatment, cytokines in the medium and cytokine mRNA in the cells were quantified using enzyme-linked immunosorbet assay and real-time polymerase chain reaction, respectively. In this study, we demonstrated that the pre-exposure of U937 histiocytes to high glucose concentrations markedly increased the lipopolysaccharide-induced secretion of pro-inflammatory cytokines and chemokines and the cellular inducible nitric oxide level compared with pre-exposure to normal glucose. Our data also showed that the increased secretion of cytokines was a result of increased mRNA expression. Furthermore, the effects of statin and peroxisome proliferators-activated receptor agonists on high glucose-enhanced secretion of cytokines were determined. The results showed that simvastatin, but not fenofibrate or pioglitazone, inhibited high glucose-enhanced cytokine release. This study has shown that high glucose concentrations and lipopolysaccharide act synergistically to stimulate the secretion of inflammatory mediators, and that statin is capable of suppressing the high glucose-boosted proinflammatory response. This study therefore delineates a novel mechanism by which hyperglycemia enhances the inflammatory responses of

  8. Metabolic regulation of lateral hypothalamic glucose-inhibited orexin neurons may influence midbrain reward neurocircuitry.

    Science.gov (United States)

    Sheng, Zhenyu; Santiago, Ammy M; Thomas, Mark P; Routh, Vanessa H

    2014-09-01

    Lateral hypothalamic area (LHA) orexin neurons modulate reward-based feeding by activating ventral tegmental area (VTA) dopamine (DA) neurons. We hypothesize that signals of peripheral energy status influence reward-based feeding by modulating the glucose sensitivity of LHA orexin glucose-inhibited (GI) neurons. This hypothesis was tested using electrophysiological recordings of LHA orexin-GI neurons in brain slices from 4 to 6week old male mice whose orexin neurons express green fluorescent protein (GFP) or putative VTA-DA neurons from C57Bl/6 mice. Low glucose directly activated ~60% of LHA orexin-GFP neurons in both whole cell and cell attached recordings. Leptin indirectly reduced and ghrelin directly enhanced the activation of LHA orexin-GI neurons by glucose decreases from 2.5 to 0.1mM by 53±12% (n=16, PFasting increased activation of LHA orexin-GI neurons by decreased glucose, as would be predicted by these hormonal effects. We also evaluated putative VTA-DA neurons in a novel horizontal slice preparation containing the LHA and VTA. Decreased glucose increased the frequency of spontaneous excitatory post-synaptic currents (sEPSCs; 125 ± 40%, n=9, P<0.05) and action potentials (n=9; P<0.05) in 45% (9/20) of VTA DA neurons. sEPSCs were completely blocked by AMPA and NMDA glutamate receptor antagonists (CNQX 20 μM, n=4; APV 20μM, n=4; respectively), demonstrating that these sEPSCs were mediated by glutamatergic transmission onto VTA DA neurons. Orexin-1 but not 2 receptor antagonism with SB334867 (10μM; n=9) and TCS-OX2-29 (2μM; n=5), respectively, blocks the effects of decreased glucose on VTA DA neurons. Thus, decreased glucose increases orexin-dependent excitatory glutamate neurotransmission onto VTA DA neurons. These data suggest that the glucose sensitivity of LHA orexin-GI neurons links metabolic state and reward-based feeding.

  9. Crude Aloe vera Gel Shows Antioxidant Propensities and Inhibits Pancreatic Lipase and Glucose Movement In Vitro

    Directory of Open Access Journals (Sweden)

    Urmeela Taukoorah

    2016-01-01

    Full Text Available Aloe vera gel (AVG is traditionally used in the management of diabetes, obesity, and infectious diseases. The present study aimed to investigate the inhibitory potential of AVG against α-amylase, α-glucosidase, and pancreatic lipase activity in vitro. Enzyme kinetic studies using Michaelis-Menten (Km and Lineweaver-Burk equations were used to establish the type of inhibition. The antioxidant capacity of AVG was evaluated for its ferric reducing power, 2-diphenyl-2-picrylhydrazyl hydrate scavenging ability, nitric oxide scavenging power, and xanthine oxidase inhibitory activity. The glucose entrapment ability, antimicrobial activity, and total phenolic, flavonoid, tannin, and anthocyanin content were also determined. AVG showed a significantly higher percentage inhibition (85.56±0.91 of pancreatic lipase compared to Orlistat. AVG was found to increase the Michaelis-Menten constant and decreased the maximal velocity (Vmax of lipase, indicating mixed inhibition. AVG considerably inhibits glucose movement across dialysis tubes and was comparable to Arabic gum. AVG was ineffective against the tested microorganisms. Total phenolic and flavonoid contents were 66.06±1.14 (GAE/mg and 60.95±0.97 (RE/mg, respectively. AVG also showed interesting antioxidant properties. The biological activity observed in this study tends to validate some of the traditional claims of AVG as a functional food.

  10. Crude Aloe vera Gel Shows Antioxidant Propensities and Inhibits Pancreatic Lipase and Glucose Movement In Vitro

    Science.gov (United States)

    Taukoorah, Urmeela; Mahomoodally, M. Fawzi

    2016-01-01

    Aloe vera gel (AVG) is traditionally used in the management of diabetes, obesity, and infectious diseases. The present study aimed to investigate the inhibitory potential of AVG against α-amylase, α-glucosidase, and pancreatic lipase activity in vitro. Enzyme kinetic studies using Michaelis-Menten (K m) and Lineweaver-Burk equations were used to establish the type of inhibition. The antioxidant capacity of AVG was evaluated for its ferric reducing power, 2-diphenyl-2-picrylhydrazyl hydrate scavenging ability, nitric oxide scavenging power, and xanthine oxidase inhibitory activity. The glucose entrapment ability, antimicrobial activity, and total phenolic, flavonoid, tannin, and anthocyanin content were also determined. AVG showed a significantly higher percentage inhibition (85.56 ± 0.91) of pancreatic lipase compared to Orlistat. AVG was found to increase the Michaelis-Menten constant and decreased the maximal velocity (V max) of lipase, indicating mixed inhibition. AVG considerably inhibits glucose movement across dialysis tubes and was comparable to Arabic gum. AVG was ineffective against the tested microorganisms. Total phenolic and flavonoid contents were 66.06 ± 1.14 (GAE)/mg and 60.95 ± 0.97 (RE)/mg, respectively. AVG also showed interesting antioxidant properties. The biological activity observed in this study tends to validate some of the traditional claims of AVG as a functional food. PMID:26880905

  11. Piracetam and TRH analogues antagonise inhibition by barbiturates, diazepam, melatonin and galanin of human erythrocyte D-glucose transport

    OpenAIRE

    2004-01-01

    Nootropic drugs increase glucose uptake into anaesthetised brain and into Alzheimer's diseased brain. Thyrotropin-releasing hormone, TRH, which has a chemical structure similar to nootropics increases cerebellar uptake of glucose in murine rolling ataxia. This paper shows that nootropic drugs like piracetam (2-oxo 1 pyrrolidine acetamide) and levetiracetam and neuropeptides like TRH antagonise the inhibition of glucose transport by barbiturates, diazepam, melatonin and endogenous neuropeptide...

  12. Dehydroepiandrosterone Inhibits Glucose Flux Through the Pentose Phosphate Pathway in Human and Mouse Endometrial Stromal Cells, Preventing Decidualization and Implantation

    OpenAIRE

    Frolova, Antonina I.; O'Neill, Kathleen; Moley, Kelle H.

    2011-01-01

    Endometrial stromal cells (ESC) must undergo a hormone-driven differentiation to form decidual cells as a requirement of proper embryo implantation. Recent studies from our laboratory have demonstrated that decidualizing cells require glucose transporter 1 expression and an increase in glucose use to complete this step. The present study focuses on the glucose-dependent molecular and metabolic pathways, which are required by ESC for decidualization. Inhibition of glycolysis had no effect on d...

  13. LXR-Mediated ABCA1 Expression and Function Are Modulated by High Glucose and PRMT2.

    Directory of Open Access Journals (Sweden)

    Maryem A Hussein

    Full Text Available High cholesterol and diabetes are major risk factors for atherosclerosis. Regression of atherosclerosis is mediated in part by the Liver X Receptor (LXR through the induction of genes involved in cholesterol transport and efflux. In the context of diabetes, regression of atherosclerosis is impaired. We proposed that changes in glucose levels modulate LXR-dependent gene expression. Using a mouse macrophage cell line (RAW 264.7 and primary bone marrow derived macrophages (BMDMs cultured in normal or diabetes relevant high glucose conditions we found that high glucose inhibits the LXR-dependent expression of ATP-binding cassette transporter A1 (ABCA1, but not ABCG1. To probe for this mechanism, we surveyed the expression of a host of chromatin-modifying enzymes and found that Protein Arginine Methyltransferase 2 (PRMT2 was reduced in high compared to normal glucose conditions. Importantly, ABCA1 expression and ABCA1-mediated cholesterol efflux were reduced in Prmt2-/- compared to wild type BMDMs. Monocytes from diabetic mice also showed decreased expression of Prmt2 compared to non-diabetic counterparts. Thus, PRMT2 represents a glucose-sensitive factor that plays a role in LXR-mediated ABCA1-dependent cholesterol efflux and lends insight to the presence of increased atherosclerosis in diabetic patients.

  14. Partial inhibition of adipose tissue lipolysis improves glucose metabolism and insulin sensitivity without alteration of fat mass.

    Directory of Open Access Journals (Sweden)

    Amandine Girousse

    Full Text Available When energy is needed, white adipose tissue (WAT provides fatty acids (FAs for use in peripheral tissues via stimulation of fat cell lipolysis. FAs have been postulated to play a critical role in the development of obesity-induced insulin resistance, a major risk factor for diabetes and cardiovascular disease. However, whether and how chronic inhibition of fat mobilization from WAT modulates insulin sensitivity remains elusive. Hormone-sensitive lipase (HSL participates in the breakdown of WAT triacylglycerol into FAs. HSL haploinsufficiency and treatment with a HSL inhibitor resulted in improvement of insulin tolerance without impact on body weight, fat mass, and WAT inflammation in high-fat-diet-fed mice. In vivo palmitate turnover analysis revealed that blunted lipolytic capacity is associated with diminution in FA uptake and storage in peripheral tissues of obese HSL haploinsufficient mice. The reduction in FA turnover was accompanied by an improvement of glucose metabolism with a shift in respiratory quotient, increase of glucose uptake in WAT and skeletal muscle, and enhancement of de novo lipogenesis and insulin signalling in liver. In human adipocytes, HSL gene silencing led to improved insulin-stimulated glucose uptake, resulting in increased de novo lipogenesis and activation of cognate gene expression. In clinical studies, WAT lipolytic rate was positively and negatively correlated with indexes of insulin resistance and WAT de novo lipogenesis gene expression, respectively. In obese individuals, chronic inhibition of lipolysis resulted in induction of WAT de novo lipogenesis gene expression. Thus, reduction in WAT lipolysis reshapes FA fluxes without increase of fat mass and improves glucose metabolism through cell-autonomous induction of fat cell de novo lipogenesis, which contributes to improved insulin sensitivity.

  15. Partial Inhibition of Adipose Tissue Lipolysis Improves Glucose Metabolism and Insulin Sensitivity Without Alteration of Fat Mass

    Science.gov (United States)

    Girousse, Amandine; Tavernier, Geneviève; Valle, Carine; Moro, Cedric; Mejhert, Niklas; Dinel, Anne-Laure; Houssier, Marianne; Roussel, Balbine; Besse-Patin, Aurèle; Combes, Marion; Mir, Lucile; Monbrun, Laurent; Bézaire, Véronic; Prunet-Marcassus, Bénédicte; Waget, Aurélie; Vila, Isabelle; Caspar-Bauguil, Sylvie; Louche, Katie; Marques, Marie-Adeline; Mairal, Aline; Renoud, Marie-Laure; Galitzky, Jean; Holm, Cecilia; Mouisel, Etienne; Thalamas, Claire; Viguerie, Nathalie; Sulpice, Thierry; Burcelin, Rémy; Arner, Peter; Langin, Dominique

    2013-01-01

    When energy is needed, white adipose tissue (WAT) provides fatty acids (FAs) for use in peripheral tissues via stimulation of fat cell lipolysis. FAs have been postulated to play a critical role in the development of obesity-induced insulin resistance, a major risk factor for diabetes and cardiovascular disease. However, whether and how chronic inhibition of fat mobilization from WAT modulates insulin sensitivity remains elusive. Hormone-sensitive lipase (HSL) participates in the breakdown of WAT triacylglycerol into FAs. HSL haploinsufficiency and treatment with a HSL inhibitor resulted in improvement of insulin tolerance without impact on body weight, fat mass, and WAT inflammation in high-fat-diet–fed mice. In vivo palmitate turnover analysis revealed that blunted lipolytic capacity is associated with diminution in FA uptake and storage in peripheral tissues of obese HSL haploinsufficient mice. The reduction in FA turnover was accompanied by an improvement of glucose metabolism with a shift in respiratory quotient, increase of glucose uptake in WAT and skeletal muscle, and enhancement of de novo lipogenesis and insulin signalling in liver. In human adipocytes, HSL gene silencing led to improved insulin-stimulated glucose uptake, resulting in increased de novo lipogenesis and activation of cognate gene expression. In clinical studies, WAT lipolytic rate was positively and negatively correlated with indexes of insulin resistance and WAT de novo lipogenesis gene expression, respectively. In obese individuals, chronic inhibition of lipolysis resulted in induction of WAT de novo lipogenesis gene expression. Thus, reduction in WAT lipolysis reshapes FA fluxes without increase of fat mass and improves glucose metabolism through cell-autonomous induction of fat cell de novo lipogenesis, which contributes to improved insulin sensitivity. PMID:23431266

  16. Partial inhibition of adipose tissue lipolysis improves glucose metabolism and insulin sensitivity without alteration of fat mass.

    Science.gov (United States)

    Girousse, Amandine; Tavernier, Geneviève; Valle, Carine; Moro, Cedric; Mejhert, Niklas; Dinel, Anne-Laure; Houssier, Marianne; Roussel, Balbine; Besse-Patin, Aurèle; Combes, Marion; Mir, Lucile; Monbrun, Laurent; Bézaire, Véronic; Prunet-Marcassus, Bénédicte; Waget, Aurélie; Vila, Isabelle; Caspar-Bauguil, Sylvie; Louche, Katie; Marques, Marie-Adeline; Mairal, Aline; Renoud, Marie-Laure; Galitzky, Jean; Holm, Cecilia; Mouisel, Etienne; Thalamas, Claire; Viguerie, Nathalie; Sulpice, Thierry; Burcelin, Rémy; Arner, Peter; Langin, Dominique

    2013-01-01

    When energy is needed, white adipose tissue (WAT) provides fatty acids (FAs) for use in peripheral tissues via stimulation of fat cell lipolysis. FAs have been postulated to play a critical role in the development of obesity-induced insulin resistance, a major risk factor for diabetes and cardiovascular disease. However, whether and how chronic inhibition of fat mobilization from WAT modulates insulin sensitivity remains elusive. Hormone-sensitive lipase (HSL) participates in the breakdown of WAT triacylglycerol into FAs. HSL haploinsufficiency and treatment with a HSL inhibitor resulted in improvement of insulin tolerance without impact on body weight, fat mass, and WAT inflammation in high-fat-diet-fed mice. In vivo palmitate turnover analysis revealed that blunted lipolytic capacity is associated with diminution in FA uptake and storage in peripheral tissues of obese HSL haploinsufficient mice. The reduction in FA turnover was accompanied by an improvement of glucose metabolism with a shift in respiratory quotient, increase of glucose uptake in WAT and skeletal muscle, and enhancement of de novo lipogenesis and insulin signalling in liver. In human adipocytes, HSL gene silencing led to improved insulin-stimulated glucose uptake, resulting in increased de novo lipogenesis and activation of cognate gene expression. In clinical studies, WAT lipolytic rate was positively and negatively correlated with indexes of insulin resistance and WAT de novo lipogenesis gene expression, respectively. In obese individuals, chronic inhibition of lipolysis resulted in induction of WAT de novo lipogenesis gene expression. Thus, reduction in WAT lipolysis reshapes FA fluxes without increase of fat mass and improves glucose metabolism through cell-autonomous induction of fat cell de novo lipogenesis, which contributes to improved insulin sensitivity.

  17. Vitamin C inhibits leptin secretion and some glucose/lipid metabolic pathways in primary rat adipocytes.

    Science.gov (United States)

    Garcia-Diaz, D F; Campion, J; Milagro, F I; Boque, N; Moreno-Aliaga, M J; Martinez, J A

    2010-07-01

    Antioxidant-based treatments are emerging as an interesting approach to possibly counteract obesity fat accumulation complications, since this is accompanied by an increased systemic oxidative stress. The aim of this study was to analyze specific metabolic effects of vitamin C (VC) on epididymal primary rat adipocytes. Cells were isolated and incubated for 72 h in culture medium, in the absence or presence of 1.6 nM insulin, within a range of VC concentrations (5-1000 microM). Glucose- and lipid-related variables as well as the secretion/expression patterns of several obesity-related genes were assessed. It was observed that VC dose dependently inhibited glucose uptake and lactate production, and also reduced glycerol release in both control and insulin-treated cells. Also, VC caused a dramatic concentration-dependent fall in leptin secretion especially in insulin-stimulated cells. In addition, VC (200 microM) induced Cdkn1a and Casp8, partially inhibited Irs3, and together with insulin drastically reduced Gpdh (listed as Gpd1 in the MGI database) gene expressions. Finally, VC and insulin down-regulatory effects were observed on extracellular and intracellular reactive oxygen species production respectively. In summary, this experimental assay describes a specific effect of VC in isolated rat adipocytes on glucose and fat metabolism, and on the secretion/expression of important obesity-related proteins.

  18. Arctigenin preferentially induces tumor cell death under glucose deprivation by inhibiting cellular energy metabolism.

    Science.gov (United States)

    Gu, Yuan; Qi, Chunting; Sun, Xiaoxiao; Ma, Xiuquan; Zhang, Haohao; Hu, Lihong; Yuan, Junying; Yu, Qiang

    2012-08-15

    Selectively eradicating cancer cells with minimum adverse effects on normal cells is a major challenge in the development of anticancer therapy. We hypothesize that nutrient-limiting conditions frequently encountered by cancer cells in poorly vascularized solid tumors might provide an opportunity for developing selective therapy. In this study, we investigated the function and molecular mechanisms of a natural compound, arctigenin, in regulating tumor cell growth. We demonstrated that arctigenin selectively promoted glucose-starved A549 tumor cells to undergo necrosis by inhibiting mitochondrial respiration. In doing so, arctigenin elevated cellular level of reactive oxygen species (ROS) and blocked cellular energy metabolism in the glucose-starved tumor cells. We also demonstrated that cellular ROS generation was caused by intracellular ATP depletion and played an essential role in the arctigenin-induced tumor cell death under the glucose-limiting condition. Furthermore, we combined arctigenin with the glucose analogue 2-deoxyglucose (2DG) and examined their effects on tumor cell growth. Interestingly, this combination displayed preferential cell-death inducing activity against tumor cells compared to normal cells. Hence, we propose that the combination of arctigenin and 2DG may represent a promising new cancer therapy with minimal normal tissue toxicity.

  19. Ghrelin Inhibition Restores Glucose Homeostasis in Hepatocyte Nuclear Factor-1α (MODY3)-Deficient Mice.

    Science.gov (United States)

    Brial, François; Lussier, Carine R; Belleville, Karine; Sarret, Philippe; Boudreau, François

    2015-09-01

    Hepatocyte nuclear factor-1α (HNF1α) is a transcription factor expressed in tissues of endoderm origin. Mutations in HNF1A are associated with maturity-onset diabetes of the young 3 (MODY3). Mice deficient for Hnf1α are hyperglycemic, with their pancreatic β-cells being defective in glucose-sensing insulin secretion. The specific mechanisms involved in this defect are unclear. Gut hormones control glucose homeostasis. Our objective was to explore whether changes in these hormones play a role in glucose homeostasis in the absence of Hnf1α. An increase in ghrelin gene transcript and a decrease in glucose-dependent insulinotropic polypeptide (GIP) gene transcripts were observed in the gut of Hnf1α-null mice. These changes correlated with an increase of ghrelin and a decrease of GIP-labeled cells. Ghrelin serological levels were significantly induced in Hnf1α-null mice. Paradoxically, GIP levels were also induced in these mice. Treatment of Hnf1α-null mice with a ghrelin antagonist led to a recovery of the diabetic symptoms. We conclude that upregulation of ghrelin in the absence of Hnf1α impairs insulin secretion and can be reversed by pharmacological inhibition of ghrelin/GHS-R interaction. These observations open up on future strategies to counteract ghrelin action in a program that could become beneficial in controlling non-insulin-dependent diabetes.

  20. Propofol attenuates high glucose-induced superoxide anion accumulation in human umbilical vein endothelial cells.

    Science.gov (United States)

    Wang, Jiaqiang; Jiang, Hui; Wang, Jing; Zhao, Yanjun; Zhu, Yun; Zhu, Minmin

    2016-12-01

    Perioperative hyperglycemia is a common clinical metabolic disorder. Hyperglycemia could induce endothelial apoptosis, dysfunction, and inflammation, resulting in endothelial injury. Propofol is a widely used anesthetic drug in clinical settings. Our previous studies indicated that propofol attenuated high glucose-induced endothelial apoptosis, dysfunction, and inflammation via inhibiting reactive oxygen species (ROS) accumulation. However, the mechanisms by which propofol reduces high glucose-induced endothelial ROS accumulation are still obscure. In this study, we examined how propofol attenuates high glucose-induced endothelial ROS accumulation. Compared with 5 mm glucose treatment, 15 mm glucose upregulated the expression of pin-1, phosphatase A2 (PP2A), p66(shc) and mitochondrial p66(shc) expression, increased p66(shc) -Ser(36) phosphorylation, and O2·- accumulation. More importantly, although propofol had no effect on 15 mm glucose-induced p66(shc) -Ser(36) phosphorylation and pin-1 expression, propofol could downregulated PP2A expression and p66(shc) expression in whole-cell and mitochondrion, resulting in the reduction of O2·- accumulation. Moreover, we demonstrated that the antioxidative effect of propofol was similar to that of calyculin A, an inhibitor of PP2A. In contrast, FTY720, an activator of PP2A, antagonized the effect of propofol. Our data indicated that the antioxidative effect of propofol was achieved by downregulating PP2A expression, resulting in the inhibition of p66(shc) -Ser(36) dephosphorylation and mitochondrial p66(shc) expression. © 2016 Société Française de Pharmacologie et de Thérapeutique.

  1. ER stress in adipocytes inhibits insulin signaling, represses lipolysis, and alters the secretion of adipokines without inhibiting glucose transport.

    Science.gov (United States)

    Xu, L; Spinas, G A; Niessen, M

    2010-08-01

    The endoplasmic reticulum (ER) is the intra-cellular site, where secreted and membrane proteins are synthesized. ER stress and activation of the unfolded protein response (UPR) contribute to insulin resistance and the development of diabetes in obesity. It was shown previously in hepatocytes that the UPR activates c-jun N-terminal kinase (JNK), which phosphorylates insulin receptor substrate (IRS) proteins on serine residues thereby inhibiting insulin signal transduction. Here we describe how ER stress affects insulin signaling and the biological function of adipocytes. In addition to inhibition of IRS we found that ER stress downregulates the expression of the insulin receptor. Concomitantly, insulin-induced activation of Akt/PKB and of ERK1/2 was strongly inhibited. Ectopic expression of IRS1 or IRS2 strongly counteracted the inhibitory effect of ER stress on insulin signaling while pharmacological inhibition of JNK with SP600125 resulted only in a mild improvement. ER stress decreased the secretion of the adipokines adiponectin and leptin, but strongly increased secretion of IL-6. ER stress inhibited expression and insulin-induced phosphorylation of AS160, reduced lipolysis but did not inhibit glucose transport. Finally, supernatants collected from 3T3-L1 adipocytes undergoing ER stress improved or impaired proliferation when used to condition the culture medium of INS-1E beta-cells dependent on the degree of ER stress. It appears that ER stress in adipocytes might initially lead to changes resembling early prediabetic stages, which at least in part support the regulation of systemic energy homeostasis. Copyright Georg Thieme Verlag KG Stuttgart New York.

  2. Glucose-induced inhibition of the appetitive brain response to visual food cues in polycystic ovary syndrome patients.

    Science.gov (United States)

    Van Vugt, Dean A; Krzemien, Alicja; Alsaadi, Hanin; Frank, Tamar C; Reid, Robert L

    2014-04-16

    We postulate that insulin regulation of food intake is compromised when insulin resistance is present. In order to investigate the effect of insulin sensitivity on appetitive brain responses, we conducted functional magnetic resonance imaging studies in a group of women diagnosed with polycystic ovary syndrome (PCOS) in which insulin sensitivity ranged from normal to resistant. Subjects (n=19) were imaged while viewing pictures of high calorie (HC) foods and low calorie (LC) foods after ingesting either 75 g glucose or an equivalent volume of water. The insulin sensitive group showed reduced blood oxygen level dependent (BOLD) signal in response to food pictures following glucose ingestion in numerous corticolimbic brain regions, whereas the insulin resistant group did not. There was a significant interaction between insulin sensitivity (sensitive vs resistant) and condition (water vs glucose). The largest clusters identified included the left insula, bilateral limbic/parahippocampal gyrus/culmen/midbrain, bilateral limbic lobe/precuneus, and left superior/mid temporal gyrus/parietal for HC and LC stimuli combined, the left parahippocampal gyrus/fusiform/pulvinar/midbrain for HC pictures, and the left superior/mid temporal gyrus/parietal and middle/inferior frontal gyrus/orbitofrontal cortex for LC pictures. Furthermore, BOLD signal in the anterior cingulate, medial frontal gyrus, posterior cingulate/precuneus, and parietal cortex during a glucose challenge correlated negatively with insulin sensitivity. We conclude the PCOS women with insulin resistance have an impaired brain response to a glucose challenge. The inability of postprandial hyperinsulinemia to inhibit brain responsiveness to food cues in insulin resistant subjects may lead to greater non-homeostatic eating.

  3. Cinnamon extract inhibits α-glucosidase activity and dampens postprandial glucose excursion in diabetic rats

    Directory of Open Access Journals (Sweden)

    Thirumurugan Kavitha

    2011-06-01

    Full Text Available Abstract Background α-glucosidase inhibitors regulate postprandial hyperglycemia (PPHG by impeding the rate of carbohydrate digestion in the small intestine and thereby hampering the diet associated acute glucose excursion. PPHG is a major risk factor for diabetic vascular complications leading to disabilities and mortality in diabetics. Cinnamomum zeylanicum, a spice, has been used in traditional medicine for treating diabetes. In this study we have evaluated the α-glucosidase inhibitory potential of cinnamon extract to control postprandial blood glucose level in maltose, sucrose loaded STZ induced diabetic rats. Methods The methanol extract of cinnamon bark was prepared by Soxhlet extraction. Phytochemical analysis was performed to find the major class of compounds present in the extract. The inhibitory effect of cinnamon extract on yeast α-glucosidase and rat-intestinal α-glucosidase was determined in vitro and the kinetics of enzyme inhibition was studied. Dialysis experiment was performed to find the nature of the inhibition. Normal male Albino wistar rats and STZ induced diabetic rats were treated with cinnamon extract to find the effect of cinnamon on postprandial hyperglycemia after carbohydrate loading. Results Phytochemical analysis of the methanol extract displayed the presence of tannins, flavonoids, glycosides, terpenoids, coumarins and anthraquinones. In vitro studies had indicated dose-dependent inhibitory activity of cinnamon extract against yeast α-glucosidase with the IC 50 value of 5.83 μg/ml and mammalian α-glucosidase with IC 50 value of 670 μg/ml. Enzyme kinetics data fit to LB plot pointed out competitive mode of inhibition and the membrane dialysis experiment revealed reversible nature of inhibition. In vivo animal experiments are indicative of ameliorated postprandial hyperglycemia as the oral intake of the cinnamon extract (300 mg/kg body wt. significantly dampened the postprandial hyperglycemia by 78.2% and 52

  4. [8-hydroxy-dihydroberberine ameliorated insulin resistance induced by high FFA and high glucose in 3T3-L1 adipocytes].

    Science.gov (United States)

    Xu, Li-jun; Lu, Fu-er; Yi, Ping; Wang, Zeng-si; Wei, Shi-chao; Chen, Guang; Dong, Hui; Zou, Xin

    2009-11-01

    The purpose of the study is to investigate the effect of 8-hydroxy-dihydroberberine on insulin resistance induced by high free fatty acid (FFA) and high glucose in 3T3-L1 adipocytes and its possible molecular mechanism. Palmic acid or glucose in combination with insulin was used to induce insulin resistance in 3T3-L1 adipocytes. 8-Hydroxy-dihydroberberine and berberine were added to the cultured medium separately, which were considered as treated group and positive control group. The rate of glucose uptake was determined by 2-deoxy-[3H]-D-glucose method. The amount of glucose consumption in the medium was measured by glucose oxidase method. Cell growth and proliferation of 3T3-L1 adipocytes were detected with Cell Counting Kit-8 (CCK-8) assay. After incubated with palmic acid for 24 hours or glucose with insulin for 18 hours, the rate of glucose transport in 3T3-L1 adipocytes was inhibited by 67% and 58%, respectively. The amount of glucose consumption in 3T3-L1 adipose cells was decreased by 41% after cells were incubated with palmic acid for 24 h. However, the above changes were reversed by pretreatment with 8-hydroxy-dihydroberberine for 24 and 48 h. Significant difference existed between groups. Insulin resistance in 3T3-L1 adipocytes, which is induced by high FFA and high glucose, could be ameliorated by 8-hydroxy-dihydroberberine.

  5. Effects of macronutrient composition and cyclooxygenase-inhibition on diet-induced obesity, low grade inflammation and glucose homeostasis

    DEFF Research Database (Denmark)

    Fjære, Even

    Background: Obesity and its related metabolic complications are an increasing problem worldwide. A high fat diet in combination with sucrose has been shown to induce obesity and development of glucose intolerance and insulin resistance in rodents. C57BL/6J mice were fed high fat diets with sucrose......- or protein based background, and supplemented with either corn- or fish oil. These experiments were conducted to determine whether macronutrient composition and type of dietary fat can modulate diet-induced obesity, and associated metabolic consequences. The use of non-steroidal anti-inflammatory drugs...... is escalating, and in view of the increased consumption of obesogenic diets with high levels of dietary carbohydrates and fat, the metabolic consequences of cyclooxygenase-inhibition warrants investigation. Results: High fat/high sucrose diets increased obesity development and expression of macrophage...

  6. Cdh1 inhibits reactive astrocyte proliferation after oxygen-glucose deprivation and reperfusion.

    Science.gov (United States)

    Qiu, Jin; Zhang, Chuanhan; Lv, Youyou; Zhang, Yue; Zhu, Chang; Wang, Xueren; Yao, Wenlong

    2013-08-01

    Anaphase-promoting complex (APC) and its co-activator Cdh1 are required for cell cycle regulation in proliferating cells. Recent studies have defined diverse functions of APC-Cdh1 in nervous system development and injury. Our previous studies have demonstrated the activity of APC-Cdh1 is down-regulated in hippocampus after global cerebral ischemia. But the detailed mechanisms of APC-Cdh1 in ischemic nervous injury are unclear. It is known that astrocyte proliferation is an important pathophysiological process following cerebral ischemia. However, the role of APC-Cdh1 in reactive astrocyte proliferation is not determined yet. In the present study, we cultured primary cerebral astrocytes and set up in vitro oxygen-glucose deprivation and reperfusion model. Our results showed that the expression of Cdh1 was decreased while Skp2 (the downstream substrate of APC-Cdh1) was increased in astrocytes after 1h oxygen-glucose deprivation and reperfusion. The down-regulation of APC-Cdh1 was coupled with reactive astrocyte proliferation. By constructing Cdh1 expressing lentivirus system, we also found exogenous Cdh1 can down-regulate Skp2 and inhibit reactive astrocyte proliferation induced by oxygen-glucose deprivation and reperfusion. Moreover, Western blot showed that other downstream proteins of APC-Cdh1, PFK-1 and SnoN, were decreased in the inhibition of reactive astrocyte proliferation with Cdh1 expressing lentivirus treatment. These results suggest that Cdh1 plays an important role in the regulation of reactive astrocyte proliferation induced by oxygen-glucose deprivation and reperfusion.

  7. Effect of Sodium-Glucose Cotransport Inhibition on Polycystic Kidney Disease Progression in PCK Rats.

    Directory of Open Access Journals (Sweden)

    Sarika Kapoor

    Full Text Available The sodium-glucose-cotransporter-2 (SGLT2 inhibitor dapagliflozin (DAPA induces glucosuria and osmotic diuresis via inhibition of renal glucose reabsorption. Since increased diuresis retards the progression of polycystic kidney disease (PKD, we investigated the effect of DAPA in the PCK rat model of PKD. DAPA (10 mg/kg/d or vehicle was administered by gavage to 6 week old male PCK rats (n=9 per group. Renal function, albuminuria, kidney weight and cyst volume were assessed after 6 weeks of treatment. Treatment with DAPA markedly increased glucose excretion (23.6 ± 4.3 vs 0.3 ± 0.1 mmol/d and urine output (57.3 ± 6.8 vs 19.3 ± 0.8 ml/d. DAPA-treated PCK rats had higher clearances for creatinine (3.1 ± 0.1 vs 2.6 ± 0.2 ml/min and BUN (1.7 ± 0.1 vs 1.2 ± 0.1 ml/min after 3 weeks, and developed a 4-fold increase in albuminuria. Ultrasound imaging and histological analysis revealed a higher cyst volume and a 23% higher total kidney weight after 6 weeks of DAPA treatment. At week 6 the renal cAMP content was similar between DAPA and vehicle, and staining for Ki67 did not reveal an increase in cell proliferation. In conclusion, the inhibition of glucose reabsorption with the SGLT2-specific inhibitor DAPA caused osmotic diuresis, hyperfiltration, albuminuria and an increase in cyst volume in PCK rats. The mechanisms which link glucosuria to hyperfiltration, albuminuria and enhanced cyst volume in PCK rats remain to be elucidated.

  8. Effect of Sodium-Glucose Cotransport Inhibition on Polycystic Kidney Disease Progression in PCK Rats.

    Science.gov (United States)

    Kapoor, Sarika; Rodriguez, Daniel; Riwanto, Meliana; Edenhofer, Ilka; Segerer, Stephan; Mitchell, Katharyn; Wüthrich, Rudolf P

    2015-01-01

    The sodium-glucose-cotransporter-2 (SGLT2) inhibitor dapagliflozin (DAPA) induces glucosuria and osmotic diuresis via inhibition of renal glucose reabsorption. Since increased diuresis retards the progression of polycystic kidney disease (PKD), we investigated the effect of DAPA in the PCK rat model of PKD. DAPA (10 mg/kg/d) or vehicle was administered by gavage to 6 week old male PCK rats (n=9 per group). Renal function, albuminuria, kidney weight and cyst volume were assessed after 6 weeks of treatment. Treatment with DAPA markedly increased glucose excretion (23.6 ± 4.3 vs 0.3 ± 0.1 mmol/d) and urine output (57.3 ± 6.8 vs 19.3 ± 0.8 ml/d). DAPA-treated PCK rats had higher clearances for creatinine (3.1 ± 0.1 vs 2.6 ± 0.2 ml/min) and BUN (1.7 ± 0.1 vs 1.2 ± 0.1 ml/min) after 3 weeks, and developed a 4-fold increase in albuminuria. Ultrasound imaging and histological analysis revealed a higher cyst volume and a 23% higher total kidney weight after 6 weeks of DAPA treatment. At week 6 the renal cAMP content was similar between DAPA and vehicle, and staining for Ki67 did not reveal an increase in cell proliferation. In conclusion, the inhibition of glucose reabsorption with the SGLT2-specific inhibitor DAPA caused osmotic diuresis, hyperfiltration, albuminuria and an increase in cyst volume in PCK rats. The mechanisms which link glucosuria to hyperfiltration, albuminuria and enhanced cyst volume in PCK rats remain to be elucidated.

  9. Tumor necrosis factor-alpha inhibits insulin's stimulating effect on glucose uptake and endothelium-dependent vasodilation in humans

    DEFF Research Database (Denmark)

    Rask-Madsen, Christian; Domínguez, Helena; Ihlemann, Nikolaj

    2003-01-01

    -alpha was smaller (PTNF-alpha had no effect on the SNP response without insulin infusion. Thus, TNF-alpha inhibition of the combined response to insulin and ACh was likely mediated through inhibition of NO production. CONCLUSIONS: These results support the concept that TNF-alpha could play a role......BACKGROUND: Inflammatory mechanisms could be involved in the pathogenesis of both insulin resistance and atherosclerosis. Therefore, we aimed at examining whether the proinflammatory cytokine tumor necrosis factor (TNF)-alpha inhibits insulin-stimulated glucose uptake and insulin....../or TNF-alpha were coinfused. During infusion of insulin alone for 20 minutes, forearm glucose uptake increased by 220+/-44%. This increase was completely inhibited during coinfusion of TNF-alpha (started 10 min before insulin) with a more pronounced inhibition of glucose extraction than of blood flow...

  10. High Glucose-Induced Oxidative Stress Increases the Copy Number of Mitochondrial DNA in Human Mesangial Cells

    Directory of Open Access Journals (Sweden)

    Ghada Al-Kafaji

    2013-01-01

    Full Text Available Oxidative damage to mitochondrial DNA (mtDNA has been linked to the pathogenicity of diabetic nephropathy. We tested the hypothesis that mtDNA copy number may be increased in human mesangial cells in response to high glucose-induced reactive oxygen species (ROS to compensate for damaged mtDNA. The effect of manganese superoxide dismutase mimetic (MnTBAP on glucose-induced mtDNA copy number was also examined. The copy number of mtDNA was determined by real-time PCR in human mesangial cells cultured in 5 mM glucose, 25 mM glucose, and mannitol (osmotic control, as well as in cells cultured in 25 mM glucose in the presence and absence of 200 μM MnTBAP. Intracellular ROS was assessed by confocal microscopy and flow cytometry in human mesangial cells. The copy number of mtDNA was significantly increased when human mesangial cells were incubated with 25 mM glucose compared to 5 mM glucose and mannitol. In addition, 25 mM glucose rapidly generated ROS in the cells, which was not detected in 5 mM glucose. Furthermore, mtDNA copy number was significantly decreased and maintained to normal following treatment of cells with 25 mM glucose and MnTBAP compared to 25 mM glucose alone. Inclusion of MnTBAP during 25 mM glucose incubation inhibited mitochondrial superoxide in human mesangial cells. Increased mtDNA copy number in human mesangial cells by high glucose could contribute to increased mitochondrial superoxide, and prevention of mtDNA copy number could have potential in retarding the development of diabetic nephropathy.

  11. ReishiMax, mushroom based dietary supplement, inhibits adipocyte differentiation, stimulates glucose uptake and activates AMPK

    Directory of Open Access Journals (Sweden)

    Sliva Daniel

    2011-09-01

    Full Text Available Abstract Background Obesity is a health hazard which is closely associated with various complications including insulin resistance, hypertension, dyslipidemia, atherosclerosis, type 2 diabetes and cancer. In spite of numerous preclinical and clinical interventions, the prevalence of obesity and its related disorders are on the rise demanding an urgent need for exploring novel therapeutic agents that can regulate adipogenesis. In the present study, we evaluated whether a dietary supplement ReishiMax (RM, containing triterpenes and polysaccharides extracted from medicinal mushroom Ganoderma lucidum, affects adipocyte differentiation and glucose uptake in 3T3-L1 cells. Methods 3T3-L1 pre-adipocytes were differentiated into adipocytes and treated with RM (0-300 μg/ml. Adipocyte differentiation/lipid uptake was evaluated by oil red O staining and triglyceride and glycerol concentrations were determined. Gene expression was evaluated by semi-quantitative RT-PCR and Western blot analysis. Glucose uptake was determined with [3H]-glucose. Results RM inhibited adipocyte differentiation through the suppresion of expression of adipogenic transcription factors peroxisome proliferator-activated receptor-γ (PPAR-γ, sterol regulatory element binding element protein-1c (SREBP-1c and CCAAT/enhancer binding protein-α (C/EBP-α. RM also suppressed expression of enzymes and proteins responsible for lipid synthesis, transport and storage: fatty acid synthase (FAS, acyl-CoA synthetase-1 (ACS1, fatty acid binding protein-4 (FABP4, fatty acid transport protein-1 (FATP1 and perilipin. RM induced AMP-activated protein kinase (AMPK and increased glucose uptake by adipocytes. Conclusion Our study suggests that RM can control adipocyte differentiation and glucose uptake. The health benefits of ReishiMax warrant further clinical studies.

  12. The chemopreventive effect of the dietary compound kaempferol on the MCF-7 human breast cancer cell line is dependent on inhibition of glucose cellular uptake.

    Science.gov (United States)

    Azevedo, Cláudia; Correia-Branco, Ana; Araújo, João R; Guimarães, João T; Keating, Elisa; Martel, Fátima

    2015-01-01

    Our aim was to investigate the effect of several dietary polyphenols on glucose uptake by breast cancer cells. Uptake of (3)H-deoxy-D-glucose ((3)H-DG) by MCF-7 cells was time-dependent, saturable, and inhibited by cytochalasin B plus phloridzin. In the short-term (26 min), myricetin, chrysin, genistein, resveratrol, kaempferol, and xanthohumol (10-100 µM) inhibited (3)H-DG uptake. Kaempferol was found to be the most potent inhibitor of (3)H-DG uptake [IC50 of 4 µM (1.6-9.8)], behaving as a mixed-type inhibitor. In the long-term (24 h), kaempferol (30 µM) was also able to inhibit (3)H-DG uptake, associated with a 40% decrease in GLUT1 mRNA levels. Interestingly enough, kaempferol (100 µM) revealed antiproliferative (sulforhodamine B and (3)H-thymidine incorporation assays) and cytotoxic (extracellular lactate dehydrogenase activity determination) properties, which were mimicked by low extracellular (1 mM) glucose conditions and reversed by high extracellular (20 mM) glucose conditions. Finally, exposure of cells to kaempferol (30 µM) induced an increase in extracellular lactate levels over time (to 731 ± 32% of control after a 24 h exposure), due to inhibition of MCT1-mediated lactate cellular uptake. In conclusion, kaempferol potently inhibits glucose uptake by MCF-7 cells, apparently by decreasing GLUT1-mediated glucose uptake. The antiproliferative and cytotoxic effect of kaempferol in these cells appears to be dependent on this effect.

  13. In vitro characterization of luseogliflozin, a potent and competitive sodium glucose co-transporter 2 inhibitor: Inhibition kinetics and binding studies.

    Science.gov (United States)

    Uchida, Saeko; Mitani, Akiko; Gunji, Emi; Takahashi, Teisuke; Yamamoto, Koji

    2015-05-01

    In this study, we evaluated an inhibition model of luseogliflozin on sodium glucose co-transporter 2 (SGLT2). We also analyzed the binding kinetics of the drug to SGLT2 protein using [(3)H]-luseogliflozin. Luseogliflozin competitively inhibited human SGLT2 (hSGLT2)-mediated glucose uptake with a Ki value of 1.10 nM. In the absence of glucose, [(3)H]-luseogliflozin exhibited a high affinity for hSGLT2 with a Kd value of 1.3 nM. The dissociation half-time was 7 h, suggesting that luseogliflozin dissociates rather slowly from hSGLT2. These profiles of luseogliflozin might contribute to the long duration of action of this drug.

  14. Mitochondrial Fission Increases Apoptosis and Decreases Autophagy in Renal Proximal Tubular Epithelial Cells Treated with High Glucose.

    Science.gov (United States)

    Lee, Wen-Chin; Chiu, Chien-Hua; Chen, Jin-Bor; Chen, Chiu-Hua; Chang, Hsueh-Wei

    2016-11-01

    The aim of this study was to examine the effect of mitochondrial morphogenesis changes on apoptosis and autophagy of high-glucose-treated proximal tubular epithelial cells (HK2). Cell viability, apoptosis, and mitochondrial morphogenesis were examined using crystal violet, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL), and mitotracker staining, respectively. High glucose inhibited cell viability and induced mitochondrial fission in HK2 cells. After depleting mitofusin 1 (MFN1), the MFN1(-) HK2 cells (fission type) became more susceptible to high-glucose-induced apoptosis and mitochondrial fragmentation observed by TUNEL and mitotracker assays. In siMFN2 HK2 cells (fission type), mitochondria were highly fragmented (>80% fission rate) with or without high-glucose treatment; however, siFIS1 (mitochondrial fission protein 1) HK2 cells (fusion type) exhibited little fragmentation (High-glucose treatment induced autophagy, characterized by the formation of autophagosome and microtubule-associated protein light chain 3 (LC3) B-II, as observed by transmission electron microscopy and western blotting, respectively. LC3B-II levels decreased in both MFN1(-) and siMFN2 HK2 cells, but increased in siFIS1 HK2 cells. Moreover, autophagy displays a protective role against high-glucose-induced cell death based on cotreatment with autophagy inhibitors (3-methyladenine and chloroquine). Mitochondrial fission may increase apoptosis and decrease autophagy of high-glucose-treated HK2 cells.

  15. Nanomolar Caffeic Acid Decreases Glucose Uptake and the Effects of High Glucose in Endothelial Cells.

    Directory of Open Access Journals (Sweden)

    Lucia Natarelli

    Full Text Available Epidemiological studies suggest that moderate and prolonged consumption of coffee is associated with a reduced risk of developing type 2 diabetes but the molecular mechanisms underlying this effect are not known. In this study, we report the effects of physiological concentrations of caffeic acid, easily achievable by normal dietary habits, in endothelial cells cultured in 25 mM of glucose (high glucose, HG. In HG, the presence of 10 nM caffeic acid was associated with a decrease of glucose uptake but not to changes of GLUT-1 membrane localization or mRNA levels. Moreover, caffeic acid countered HG-induced loss of barrier integrity, reducing actin rearrangement and FITC-dextran passage. The decreased flux of glucose associated to caffeic acid affected HG induced apoptosis by down-regulating the expression of initiator (caspase 8 and 9 and effector caspases (caspase 7 and 3 and by increasing the levels of phosphorylated Bcl-2. We also observed that caffeic acid in HG condition was associated to a reduction of p65 subunit nuclear levels with respect to HG alone. NF-κB activation has been shown to lead to apoptosis in HG treated cells and the analysis of the expression of a panel of about 90 genes related to NF-κB signaling pathway revealed that caffeic acid significantly influenced gene expression changes induced by HG. In conclusion, our results suggest that caffeic acid, decreasing the metabolic stress induced by HG, allows the activation of survival mechanisms mediated by a different modulation of NF-κB-related signaling pathways and to the activation of anti-apoptotic proteins.

  16. Inhibition of murine splenic T lymphocyte proliferation by 2-deoxy-D-glucose-induced metabolic stress

    Science.gov (United States)

    Miller, E. S.; Klinger, J. C.; Akin, C.; Koebel, D. A.; Sonnenfeld, G.

    1994-01-01

    Female Swiss-Webster mice were injected with the glucose analogue 2-deoxy-D-glucose (2-DG), which when administered to rodents induces acute periods of metabolic stress. A single or multiple injections of 2-DG invoked a stress response, as evidenced by increases in serum corticosterone levels. The influence of this metabolic stressor on the blastogenic potential of splenic T lymphocytes was then examined. It was found that one, two, or three injections of 2-DG resulted in depressed T cell proliferative responses, with an attenuation of the effect occurring by the fifth injection. The 2-DG-induced inhibition of T cell proliferation was not attributable to 2-DG-induced cytolysis, as in vitro incubation of naive T cells with varying concentrations of 2-DG did not result in a reduction in cell number or viability, and flow cytometric analysis demonstrated that percentages of CD3, CD4, and CD8 splenic T cells were not altered as a result of 2-DG-induced stress. Incubating naive T cells in varying concentrations of 2-DG resulted in a dose-dependent inhibition of T cell blastogenic potential. Following in vivo exposure to 2-DG, T cell proliferation did not return to normal levels until 3 days after the cessation of 2-DG injections. Administering the beta-adrenergic receptor antagonist propranolol did not reverse the inhibited lymphoproliferation in 2-DG-treated mice. The inhibition in T cell proliferation was not observed, however, in mice that had been adrenalectomized or hypophysectomized and injected with 2-DG.(ABSTRACT TRUNCATED AT 250 WORDS).

  17. Inhibitive potentiometric detection of trace metals with ultrathin polypyrrole glucose oxidase biosensor.

    Science.gov (United States)

    Ayenimo, Joseph G; Adeloju, Samuel B

    2015-05-01

    A method, based on the inhibition of an ultrathin polypyrrole-glucose oxidase (PPy-GOx) potentiometric biosensor response, is described for the detection of Cu(2+), Hg(2+), Cd(2+) and Pb(2+) ions. Based on experimental conditions (0.2 M pyrrole, 500 U mL(-1) GOx, and an applied current density of 0.05 mA cm(-2) and a polymerization period of 500s) previously published by us, PPy-GOx films of approximately 55 nm thick were used to demonstrate the inhibitive potentiometric detection of selected trace metals down to 0.079 μM Cu(2+), 0.025 μM Hg(2+), 0.024 μM Pb(2+) and 0.044 μM Cd(2+). Furthermore, good linear concentration ranges were achieved for Cu(2+) (0.079-16 μM), Hg(2+) (0.025-5 μM), Pb(2+) (0.10-15 μM) and Cd(2+) (0.04-62 μM). The analysis of the nature of the inhibition of glucose oxidase in the PPy-GOx biosensor by these metals was achieved by Dixon and Cornish-Bowden plots. The shapes of the curves (exponential decay, parabolic and linear) obtained for the inhibitors suggest that the inhibition by the metal ions may not be exclusively directed at the essential -SH group, but involve additional binding sites of the enzyme. Dixon and Cornish-Bowden plots suggest that the inhibition is competitive for Cd(2+), while non-competitive inhibition was observed for other metal ions. The ultra-thin PPy-GOx film enabled improved permeability to the metal inhibitors than possible with conventional biosensors with thicker films and, hence, better reflects the actual inhibition effect of the trace metals on the enzyme activity. The use of the ultra-thin film also eliminated the usual need for incubation of the enzyme electrode for a long period in the presence of the inhibitors. Furthermore, a rapid recovery of the enzyme activity was achieved by simply washing the electrode with water and storing in phosphate buffer for 10-15 min. The proposed biosensing approach was successfully used for the detection of individual trace metals in tap water, achieving a 98

  18. Autophagy Protects Against Senescence and Apoptosis via the RAS-Mitochondria in High-Glucose-Induced Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Fei Chen

    2014-04-01

    Full Text Available Backgrounds: Autophagy is an important process in the pathogenesis of diabetes and plays a critical role in maintaining cellular homeostasis. However, the autophagic response and its mechanism in diabetic vascular endothelium remain unclear. Methods and Results: We studied high-glucose-induced renin-angiotensin system (RAS-mitochondrial damage and its effect on endothelial cells. With regard to therapeutics, we investigated the beneficial effect of angiotensin-converting enzyme inhibitors (ACEIs or angiotensin II type 1 receptor blockers (ARBs against high-glucose-induced endothelial responses. High glucose activated RAS, enhanced mitochondrial damage and increased senescence, apoptosis and autophagic-responses in endothelial cells, and these effects were mimicked by using angiotensin II (Ang. The use of an ACEI or ARB, however, inhibited the negative effects of high glucose. Direct mitochondrial injury caused by carbonyl cyanide 3-chlorophenylhydrazone (CCCP resulted in similar negative effects of high glucose or Ang and abrogated the protective effects of an ACEI or ARB. Additionally, by impairing autophagy, high-glucose-induced senescence and apoptosis were accelerated and the ACEI- or ARB-mediated beneficial effects were abolished. Furthermore, increases in FragEL™ DNA Fragmentation (TUNEL-positive cells, β-galactosidase activation and the expression of autophagic biomarkers were revealed in diabetic patients and rats, and the treatment with an ACEI or ARB decreased these responses. Conclusions: These data suggest that autophagy protects against senescence and apoptosis via RAS-mitochondria in high-glucose-induced endothelial cells.

  19. Liraglutide prevents high glucose level induced insulinoma cells apoptosis by targeting autophagy

    Institute of Scientific and Technical Information of China (English)

    CHEN Ze-fang; LI Yan-bo; HAN Jun-yong; YIN Jia-jing; WANG Yang; ZHU Li-bo; XIE Guang-ying

    2013-01-01

    Background The pathophysiology of type 2 diabetes is progressive pancreatic beta cell failure with consequential reduced insulin secretion.Glucotoxicity results in the reduction of beta cell mass in type 2 diabetes by inducing apoptosis.Autophagy is essential for the maintenance of normal islet architecture and plays a crucial role in maintaining the intracellular insulin content by accelerating the insulin degradation rate in beta cells.Recently more attention has been paid to the effect of autophagy in type 2 diabetes.The regulatory pathway of autophagy in controlling pancreatic beta cells is still not clear.The aim of our study was to evaluate whether liraglutide can inhibit apoptosis and modulate autophagy in vitro in insulinoma cells (INS-1 cells).Methods INS-1 cells were incubated for 24 hours in the presence or absence of high levels of glucose,liraglutide (a long-acting human glucagon-like peptide-1 analogue),or 3-methyadenine (3-MA).Cell viability was measured using the Cell Counting Kit-8 (CCK8) viability assay.Autophagy of INS-1 cells was tested by monodansylcadaverine (MDC)staining,an autophagy fluorescent compound used for the labeling of autophagic vacuoles,and by Western blotting of microtubule-associated protein I light chain 3 (LC3),a biochemical markers of autophagic initiation.Results The viability of INS-1 cells was reduced after treatment with high levels of glucose.The viability of INS-1 cells was reduced and apoptosis was increased when autophagy was inhibited.The viability of INS-1 cells was significantly increased by adding liraglutide to supplement high glucose level medium compared with the cells treated with high glucose levels alone.Conclusions Apoptosis and autophagy were increased in rat INS-1 cells when treated with high level of glucose,and the viability of INS-1 cells was significantly reduced by inhibiting autophagy.Liraglutide protected INS-1 cells from high glucose level-induced apoptosis that is accompanied by a significant

  20. GLUT1 and GLUT9 as major contributors to glucose influx in HepG2 cells identified by a high sensitivity intramolecular FRET glucose sensor.

    Science.gov (United States)

    Takanaga, Hitomi; Chaudhuri, Bhavna; Frommer, Wolf B

    2008-04-01

    Genetically encoded FRET glucose nanosensors have proven to be useful for imaging glucose flux in HepG2 cells. However, the dynamic range of the original sensor was limited and thus it did not appear optimal for high throughput screening of siRNA populations for identifying proteins involved in regulation of sugar flux. Here we describe a hybrid approach that combines linker-shortening with fluorophore-insertion to decrease the degrees of freedom for fluorophore positioning leading to improved nanosensor dynamics. We were able to develop a novel highly sensitive FRET nanosensor that shows a 10-fold higher ratio change and dynamic range (0.05-11 mM) in vivo, permitting analyses in the physiologically relevant range. As a proof of concept that this sensor can be used to screen for proteins playing a role in sugar flux and its control, we used siRNA inhibition of GLUT family members and show that GLUT1 is the major glucose transporter in HepG2 cells and that GLUT9 contributes as well, however to a lower extent. GFP fusions suggest that GLUT1 and 9 are preferentially localized to the plasma membrane and thus can account for the transport activity. The improved sensitivity of the novel glucose nanosensor increases the reliability of in vivo glucose flux analyses, and provides a new means for the screening of siRNA collections as well as drugs using high-content screens.

  1. GLUT1 and GLUT9 as the major contributors to glucose influx in HEPG2 cells identified by a high sensitivity intramolecular FRET glucose sensor

    Science.gov (United States)

    Takanaga, Hitomi; Chaudhuri, Bhavna; Frommer, Wolf B.

    2008-01-01

    Genetically encoded FRET-glucose nanosensors have proven to be useful for imaging glucose flux in HepG2 cells. However, the dynamic range of the original sensor was limited and thus it did not appear optimal for high throughput screening of siRNA populations for identifying proteins involved in regulation of sugar flux. Here we describe a hybrid approach that combines linker-shortening with fluorophore-insertion to decrease the degrees of freedom for fluorophore positioning leading to improved nanosensor dynamics. We were able to develop a novel highly sensitive FRET nanosensor that shows a 10-fold higher ratio change and dynamic range (0.05–11 mM) in vivo, permitting analyses in the physiologically relevant range. As a proof of concept that this sensor can be used to screen for proteins playing a role in sugar flux and its control, we used siRNA inhibition of GLUT family members and show that GLUT1 is the major glucose transporter in HepG2 cells and that GLUT9 contributes also, however to a lower extent. GFP fusions suggest that GLUT1 and 9 are preferentially localized to the plasma membrane and thus can account for the transport activity. The improved sensitivity of the novel glucose nanosensor increases the reliability of in vivo glucose flux analyses, and provides a new means for the screening of siRNA collections as well as drugs using high-content screens. PMID:18177733

  2. On-plate enzyme and inhibition assay of glucose-6-phosphate dehydrogenase using thin-layer chromatography.

    Science.gov (United States)

    Tian, Miaomiao; Mohamed, Amara Camara; Wang, Shengtian; Yang, Li

    2015-08-01

    We performed on-plate enzyme and inhibition assays of glucose 6-phosphate dehydrogenase using thin-layer chromatography. The assays were accomplished based on different retardation factors of the substrates, enzyme, and products. All the necessary steps were integrated on-plate in one developing process, including substrate/enzyme mixing, reaction starting, and quenching as well as product separation. In order to quantitatively measure the enzyme reaction, the developed plate was then densitometrically evaluated to determine the peak area of the product. Rapid and high-throughput assays were achieved by loading different substrate spots and/or enzyme (and inhibition) spots in different tracks on the plate. The on-plate enzyme assay could be finished in a developing time of only 4 min, with good track-to-track and plate-to-plate repeatability. Moreover, we determined the Km values of the enzyme reaction and Ki values of the inhibition (Pb(2+) Cd(2+) and Cu(2+) as inhibitors), as well as the corresponding kinetics using the on-plate assay. Taken together, our method expanded the application of thin-layer chromatography in enzyme assays, and it could be potentially used in research fields for rapid and quantitative measurement of enzyme activity and inhibition. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Inhibition of kidney proximal tubular glucose reabsorption does not prevent against diabetic nephropathy in type 1 diabetic eNOS knockout mice.

    Directory of Open Access Journals (Sweden)

    Muralikrishna Gangadharan Komala

    Full Text Available BACKGROUND AND OBJECTIVE: Sodium glucose cotransporter 2 (SGLT2 is the main luminal glucose transporter in the kidney. SGLT2 inhibition results in glycosuria and improved glycaemic control. Drugs inhibiting this transporter have recently been approved for clinical use and have been suggested to have potential renoprotective benefits by limiting glycotoxicity in the proximal tubule. We aimed to determine the renoprotective benefits of empagliflozin, an SGLT2 inhibitor, independent of its glucose lowering effect. RESEARCH DESIGN AND METHODS: We induced diabetes using a low dose streptozotocin protocol in 7-8 week old endothelial nitric oxide (eNOS synthase knockout mice. We measured fasting blood glucose on a monthly basis, terminal urinary albumin/creatinine ratio. Renal histology was assessed for inflammatory and fibrotic changes. Renal cortical mRNA transcription of inflammatory and profibrotic cytokines, glucose transporters and protein expression of SGLT2 and GLUT1 were determined. Outcomes were compared to diabetic animals receiving the angiotensin receptor blocker telmisartan (current best practice. RESULTS: Diabetic mice had high matched blood glucose levels. Empagliflozin did not attenuate diabetes-induced albuminuria, unlike telmisartan. Empagliflozin did not improve glomerulosclerosis, tubular atrophy, tubulointerstitial inflammation or fibrosis, while telmisartan attenuated these. Empagliflozin did not modify tubular toll-like receptor-2 expression in diabetic mice. Empagliflozin did not reduce the upregulation of macrophage chemoattractant protein-1 (MCP-1, transforming growth factor β1 and fibronectin mRNA observed in the diabetic animals, while telmisartan decreased transcription of MCP-1 and fibronectin. Empagliflozin increased GLUT1 mRNA expression and telmisartan increased SGLT2 mRNA expression in comparison to untreated diabetic mice. However no significant difference was found in protein expression of GLUT1 or SGLT2 among the

  4. The impact of high-dose vitamin C on blood glucose testing in ¹⁸F-FDG PET imaging.

    Science.gov (United States)

    Bahr, Rebekah L; Wilson, Don C

    2015-03-01

    Complementary and alternative therapies in addition to standard oncology protocols are commonly sought by cancer patients; however, few patients disclose their complementary treatments to their cancer care team. A lack of communication may result in unforeseen side effects and the potential for some alternative therapies to interfere with or inhibit conventional treatment. High-dose vitamin C therapy, in particular, may lead to an inability to measure a patient's blood glucose level before (18)F-FDG injection for PET/CT scanning. We report a case of a 52-y-old woman referred for (18)F-FDG PET/CT to evaluate the extent of recurrent colorectal cancer. The PET/CT scan immediately followed a single intravenous dose of 25 g of ascorbic acid from her naturopath. A glucometer that applies the glucose oxidase method for measuring fasting blood glucose was used, for which high doses of vitamin C are listed as a contraindication. The high concentration of ascorbic acid in the patient's blood sample interfered with the chemical reaction on the glucose strip, and therefore no blood glucose measurement could be attained. With more patients receiving alternative and complementary cancer therapies, it is important to know what the implications of orthomolecular therapy might be on routine blood glucose testing for (18)F-FDG PET scans. (18)F-FDG is in direct competition with glucose; therefore, elevated blood glucose levels will cause a decrease in (18)F-FDG absorption and may lead to a false-negative scan.

  5. Inhibition of GSK-3 induces differentiation and impaired glucose metabolism in renal cancer

    Science.gov (United States)

    Pal, Krishnendu; Cao, Ying; Gaisina, Irina N.; Bhattacharya, Santanu; Dutta, Shamit K.; Wang, Enfeng; Gunosewoyo, Hendra; Kozikowski, Alan P.; Billadeau, Daniel D.; Mukhopadhyay, Debabrata

    2014-01-01

    Glycogen synthase kinase-3 (GSK-3), a constitutively active serine/threonine kinase, is a key regulator of numerous cellular processes ranging from glycogen metabolism to cell cycle regulation and proliferation. Consistent with its involvement in many pathways, it has also been implicated in the pathogenesis of various human diseases including Type II diabetes, Alzheimer's disease, bipolar disorder, inflammation and cancer. Consequently it is recognized as an attractive target for the development of new drugs. In the present study, we investigated the effect of both pharmacological and genetic inhibition of GSK-3 in two different renal cancer cell lines. We have shown potent anti-proliferative activity of 9-ING-41, a maleimide-based GSK-3 inhibitor. The anti-proliferative activity is most likely caused by G0–G1 and G2-M phase arrest as evident from cell cycle analysis. We have established that inhibition of GSK-3 imparted a differentiated phenotype in renal cancer cells. We have also shown that GSK-3 inhibition induced autophagy, likely as a result of imbalanced energy homeostasis caused by impaired glucose metabolism. Additionally, we have demonstrated the antitumor activity of 9-ING-41 in two different subcutaneous xenograft RCC tumor models. To our knowledge, this is the first report describing autophagy induction due to GSK-3 inhibition in renal cancer cells. PMID:24327518

  6. Competitive inhibition of SGLT2 by tofogliflozin or phlorizin induces urinary glucose excretion through extending splay in cynomolgus monkeys.

    Science.gov (United States)

    Nagata, Takumi; Suzuki, Masayuki; Fukazawa, Masanori; Honda, Kiyofumi; Yamane, Mizuki; Yoshida, Ayae; Azabu, Hiroko; Kitamura, Hidekazu; Toyota, Naoto; Suzuki, Yoshiyuki; Kawabe, Yoshiki

    2014-06-15

    Sodium-glucose cotransporter 2 (SGLT2) inhibitors showed a glucose lowering effect in type 2 diabetes patients through inducing renal glucose excretion. Detailed analysis of the mechanism of the glucosuric effect of SGLT2 inhibition, however, has been hampered by limitations of clinical study. Here, we investigated the mechanism of urinary glucose excretion using nonhuman primates with SGLT inhibitors tofogliflozin and phlorizin, both in vitro and in vivo. In cells overexpressing cynomolgus monkey SGLT2 (cSGLT2), both tofogliflozin and phlorizin competitively inhibited uptake of the substrate (α-methyl-d-glucopyranoside; AMG). Tofogliflozin was found to be a selective cSGLT2 inhibitor, inhibiting cSGLT2 more strongly than did phlorizin, with selectivity toward cSGLT2 1,000 times that toward cSGLT1; phlorizin was found to be a nonselective cSGLT1/2 inhibitor. In a glucose titration study in cynomolgus monkeys under conditions of controlled plasma drug concentration, both tofogliflozin and phlorizin increased fractional excretion of glucose (FEG) by up to 50% under hyperglycemic conditions. By fitting the titration curve using a newly introduced method that avoids variability in estimating the threshold of renal glucose excretion, we found that tofogliflozin and phlorizin lowered the threshold and extended the splay in a dose-dependent manner without significantly affecting the tubular transport maximum for glucose (TmG). Our results demonstrate the contribution of SGLT2 to renal glucose reabsorption (RGR) in cynomolgus monkeys and demonstrate that competitive inhibition of cSGLT2 exerts a glucosuric effect by mainly extending splay and lowering threshold without affecting TmG.

  7. Zerumbone protects INS-1 rat pancreatic beta cells from high glucose-induced apoptosis through generation of reactive oxygen species.

    Science.gov (United States)

    Wang, Changyin; Zou, Shibo; Cui, Zhengjun; Guo, Pengfei; Meng, Qingnan; Shi, Xun; Gao, Ya; Yang, Gaoyuan; Han, Zhaofeng

    2015-05-01

    The aim of this study is to explore the effect of zerumbone, a natural sesquiterpene isolated from Zingiber zerumbet Smith, on high glucose-induced cytotoxicity in pancreatic β cells. INS-1 rat pancreatic β cells were treated with 33 mM glucose with or without different concentrations of zerumbone and cell viability and apoptosis were assessed. The involvement of reactive oxygen species (ROS) and mitogen-activated protein kinase (MAPK) signaling in the action of zerumbone was examined. Notably, zerumbone significantly (P in a concentration-dependent fashion up to 60 μM of zerumbone. Annexin-V/propidium iodide staining analysis showed that zerumbone impaired the apoptotic response of high glucose-treated INS-1 cells, which was coupled with a significant decline in cleaved caspase-3 and caspase-9. Pretreatment with the ROS inhibitor N-acetylcysteine abrogated the phosphorylation of p38 and JNK induced by high glucose. Zerumbone significantly (P in high glucose-treated INS-1 cells. Pharmacological activation of p38 and JNK with anisomycin reversed the anti-apoptotic effect of zerumbone. Additionally, simultaneous inhibition of p38 and JNK significantly (P in high glucose-treated INS-1 cells. In conclusion, zerumbone confers protection against high glucose-induced apoptosis of INS-1 pancreatic β cells, largely through interfering with ROS production and p38 and JNK activation. Zerumbone may have potential therapeutic effects against hyperglycemia-induced β cell damage in diabetes.

  8. Dietary Flavonoids and Acarbose Synergistically Inhibit alpha-Glucosidase and Lower Postprandial Blood Glucose.

    Science.gov (United States)

    Zhang, Bowei; Li, Xia; Sun, Wenlong; Xing, Yan; Xiu, Zhilong; Zhuang, Chunlin; Dong, Yuesheng

    2017-09-06

    The inhibition of porcine pancreatic α-amylase and mammalian α-glucosidase by sixteen individual flavonoids was determined. The IC50 values for baicalein, (+)-catechin, quercetin, and luteolin were 74.1 ± 5.6, 175.1 ± 9.1, 281.2 ± 19.2, and 339.4 ± 16.3 μM, respectively, against α-glucosidase. The IC50 values for apigenin and baicalein were 146.8 ± 7.1 and 446.4 ± 23.9 μM, respectively, against α-amylase. The combination of baicalein, quercetin or luteolin with acarbose showed synergistic inhibition, and the combination of (+)-catechin with acarbose showed antagonistic inhibition of α-glucosidase. The combination of baicalein or apigenin with acarbose showed additive inhibition of α-amylase at lower concentrations and antagonistic inhibition at a higher concentration. Kinetic studies of α-glucosidase activity revealed that baicalein alone, acarbose alone, and the combination showed non-competitive, competitive, and mixed-type inhibition, respectively. Molecular modeling revealed that baicalein had higher affinity to the non-competitive binding site of maltase, glucoamylase, and isomaltase subunits of α-glucosidase, with glide scores of -7.64, -6.98, and -6.88, respectively. (+)-Catechin had higher affinity to the active sites of maltase and glucoamylase and to the non-competitive site of isomaltase. After sucrose loading, baicalein dose-dependently reduced the postprandial blood glucose (PBG) level in mice. The combination of 80 mg/kg baicalein and 1 mg/kg acarbose synergistically lowered the level of PBG, and the hypoglycemic effect was comparable to 8 mg/kg acarbose. The results indicated that baicalein could be used as a supplemental drug or dietary supplement in dietary therapy for diabetes mellitus.

  9. Thermoanaerobacterium thermosaccharolyticum β-glucosidase: a glucose-tolerant enzyme with high specific activity for cellobiose

    Directory of Open Access Journals (Sweden)

    Pei Jianjun

    2012-07-01

    Full Text Available Abstract Background β-Glucosidase is an important component of the cellulase enzyme system. It does not only participate in cellulose degradation, it also plays an important role in hydrolyzing cellulose to fermentable glucose by relieving the inhibition of exoglucanase and endoglucanase from cellobiose. Therefore, the glucose-tolerant β-glucosidase with high specific activity for cellobiose might be a potent candidate for industrial applications. Results The β-glucosidase gene bgl that encodes a 443-amino-acid protein was cloned and over-expressed from Thermoanaerobacterium thermosaccharolyticum DSM 571 in Escherichia coli. The phylogenetic trees of β-glucosidases were constructed using Neighbor-Joining (NJ and Maximum-Parsimony (MP methods. The phylogeny and amino acid analysis indicated that the BGL was a novel β-glucosidase. By replacing the rare codons for the N-terminal amino acids of the target protein, the expression level of bgl was increased from 6.6 to 11.2 U/mg in LB medium. Recombinant BGL was purified by heat treatment followed by Ni-NTA affinity. The optimal activity was at pH 6.4 and 70°C. The purified enzyme was stable over pH range of 5.2–7.6 and had a 1 h half life at 68°C. The activity of BGL was significantly enhanced by Fe2+ and Mn2+. The Vmax of 64 U/mg and 120 U/mg were found for p-nitrophenyl-β-D-glucopyranoside (Km value of 0.62 mM and cellobiose (Km value of 7.9 mM, respectively. It displayed high tolerance to glucose and cellobiose. The Kcat for cellobiose was 67.7 s-1 at 60°C and pH 6.4, when the concentration of cellobiose was 290 mM. It was activated by glucose at concentrations lower that 200 mM. With glucose further increasing, the enzyme activity of BGL was gradually inhibited, but remained 50% of the original value in even as high as 600 mM glucose. Conclusions The article provides a useful novel β-glucosidase which displayed favorable properties: high glucose and cellobiose tolerance

  10. Protective Pleiotropic Effect of Flavonoids on NAD+ Levels in Endothelial Cells Exposed to High Glucose

    Directory of Open Access Journals (Sweden)

    Daniëlle M. P. H. J. Boesten

    2015-01-01

    Full Text Available NAD+ is important for oxidative metabolism by serving as an electron transporter. Hyperglycemia decreases NAD+ levels by activation of the polyol pathway and by overactivation of poly(ADP-ribose-polymerase (PARP. We examined the protective role of three structurally related flavonoids (rutin, quercetin, and flavone during high glucose conditions in an in vitro model using human umbilical vein endothelial cells (HUVECs. Additionally we assessed the ability of these flavonoids to inhibit aldose reductase enzyme activity. We have previously shown that flavonoids can inhibit PARP activation. Extending these studies, we here provide evidence that flavonoids are also able to protect endothelial cells against a high glucose induced decrease in NAD+. In addition, we established that flavonoids are able to inhibit aldose reductase, the key enzyme in the polyol pathway. We conclude that this protective effect of flavonoids on NAD+ levels is a combination of the flavonoids ability to inhibit both PARP activation and aldose reductase enzyme activity. This study shows that flavonoids, by a combination of effects, maintain the redox state of the cell during hyperglycemia. This mode of action enables flavonoids to ameliorate diabetic complications.

  11. The impact of dipeptidyl peptidase 4 inhibition on incretin effect, glucose tolerance, and gastrointestinal-mediated glucose disposal in healthy subjects

    DEFF Research Database (Denmark)

    Rhee, Nicolai Alexander; Østoft, Signe Harring; Holst, Jens Juul

    2014-01-01

    /mol [5.3±0.1%]) were randomised to two paired study days comprising a 4h 50 g-OGTT with paracetamol (A) and an isoglycaemic i.v. glucose infusion (IIGI) (B), with (A1+B1) and without (A2+B2) preceding administration of the DPP-4 inhibitor sitagliptin. Results Isoglycaemia was obtained in all subjects...... gastric emptying (Tmax for plasma paracetamol: 86±9 vs 80±12 min, p=0.60) changed following DPP-4 inhibition. Conclusions These results suggest that acute increases in active incretin hormone levels do not affect glucose tolerance, GIGD, incretin effect, glucagon responses or gastric emptying in healthy...

  12. Long-term inhibition of dipeptidyl peptidase IV improves glucose tolerance and preserves islet function in mice

    DEFF Research Database (Denmark)

    Reimer, M Kvist; Holst, Jens Juul; Ahrén, B

    2002-01-01

    and such mice rendered glucose-intolerant and insulin-resistant by feeding a high-fat diet. DESIGN: In mice fed a standard diet (11% fat) or a high-fat diet (58% fat), NVP DPP728 (0.12 micromol/g body weight) was administered in the drinking water for an 8 week period. RESULTS: DPPIV inhibition reduced plasma......OBJECTIVES: Inhibitors of the glucagon-like peptide-1 (GLP-1)-degrading enzyme, dipeptidyl peptidase IV (DPPIV), are being explored in the treatment of diabetes. We examined the long-term influence of a selective, orally active inhibitor of DPPIV (NVP DPP728), in normal female C57BL/6J mice...

  13. The role of cysteine residues in glucose-transporter-GLUT1-mediated transport and transport inhibition.

    Science.gov (United States)

    Wellner, M; Monden, I; Keller, K

    1994-01-01

    The role of cysteine residues in transport function of the glucose transporter GLUT1 was investigated by a mutagenesis-expression strategy. Each of the six cysteine residues was individually replaced by site-directed mutagenesis. Expression of the heterologous wild-type or mutant glucose transporters and transport measurements at two hexose concentrations (50 microM and 5 mM) were undertaken in Xenopus oocytes. The catalytic activity of GLUT1 was retained, despite substitution of each single cysteine residue, which indicated that no individual residue is essential for hexose transport. This finding questions the involvement of oligomerization or intramolecular stabilization by a single disulphide bond as a prerequisite for transporter activation under basal conditions. Application of the impermeant mercurial thiol-group-reactive reagent p-chloromercuribenzenesulphonate (pCMBS) to the external or internal surface of plasma membrane demonstrated that cysteine-429, within the sixth external loop, and cysteine-207, at the beginning of the large intracellular loop which connects transmembrane segments 6 and 7, are the residues which are involved in transport inhibition by impermeant thiol-group-reactive reagents from either side of the cell. These data support the predicted membrane topology of the transport protein by transport measurements. If residues other than the cysteines at positions 429 or 207 are exposed to either side of the plasma membrane by conformational changes, they do not contribute to the transport inhibition by pCMBS. Application of pCMBS to one side of the plasma membrane also inhibited transport from the opposite direction, most likely due to the hindrance of sugar-induced interconversion of transporter conformation. PMID:8192671

  14. Glucose-induced thermogenesis in patients with small cell lung carcinoma. The effect of acute beta-adrenergic inhibition

    DEFF Research Database (Denmark)

    Simonsen, L; Bülow, J; Tuxen, C

    1994-01-01

    Seven patients with histologically verified small cell lung carcinoma were given an oral glucose load of 75 g on two occasions to examine the effect of glucose on whole body and forearm thermogenesis with and without acute beta-adrenergic inhibition with propranolol. Whole body energy expenditure...... was measured by the open circuit ventilated hood system. Forearm blood flow was measured by venous occlusion strain-gauge plethysmography. The uptake of oxygen in the forearm was calculated as the product of the forearm blood flow and the difference in arteriovenous oxygen concentration. The glucose......-induced forearm oxygen uptake in the period 60-120 min following the glucose load was significantly reduced after beta-adrenergic inhibition from 103 +/- 28 mumol 100 g-1 60 min-1 to 29 +/- 29 mumol 100 g-1 60 min-1 (P blood was not increased...

  15. Cellulase Inhibition by High Concentrations of Monosaccharides

    DEFF Research Database (Denmark)

    Hsieh, Chia-Wen; Cannella, David; Jørgensen, Henning

    2014-01-01

    that low free water availability contributes to cellulase inhibition. Of the hydrolytic enzymes involved, those acting on the cellulose substrate, that is, exo- and endoglucanases, were the most inhibited. The β -glucosidases were shown to be less sensitive to high monosaccharide concentrations except...

  16. Apigenin inhibits the proliferation of adenoid cystic carcinoma via suppression of glucose transporter-1

    Science.gov (United States)

    FANG, JIN; BAO, YANG-YANG; ZHOU, SHUI-HONG; FAN, JUN

    2015-01-01

    Apigenin is a natural phyto-oestrogen flavonoid, which exerts various biological effects, including anti-oxidative, anti-inflammatory and anticancer activities. In addition, apigenin has recently been reported to target hypoxic markers; however, there are currently no studies regarding the association between apigenin and glucose transporter-1 (GLUT-1) in adenoid cystic carcinoma (ACC). The present study investigated whether apigenin inhibits the proliferation of ACC cells or suppresses the expression of GLUT-1 in ACC cells. The results of the present study demonstrated that apigenin inhibits ACC-2 cell growth in a dose- and time-dependent manner. Treatment with apigenin also induced apoptosis and G2/M-phase arrest in a dose- and time-dependent manner. Corresponding with the above results, the expression levels of GLUT-1 were significantly decreased following treatment in a dose- and time-dependent manner. These results suggest that the inhibition of ACC-2 cell growth by apigenin may be due to the decreased expression of GLUT-1. PMID:26300442

  17. Apigenin inhibits the proliferation of adenoid cystic carcinoma via suppression of glucose transporter-1.

    Science.gov (United States)

    Fang, Jin; Bao, Yang-Yang; Zhou, Shui-Hong; Fan, Jun

    2015-11-01

    Apigenin is a natural phyto-oestrogen flavonoid, which exerts various biological effects, including anti‑oxidative, anti‑inflammatory and anticancer activities. In addition, apigenin has recently been reported to target hypoxic markers; however, there are currently no studies regarding the association between apigenin and glucose transporter‑1 (GLUT‑1) in adenoid cystic carcinoma (ACC). The present study investigated whether apigenin inhibits the proliferation of ACC cells or suppresses the expression of GLUT‑1 in ACC cells. The results of the present study demonstrated that apigenin inhibits ACC‑2 cell growth in a dose‑ and time‑dependent manner. Treatment with apigenin also induced apoptosis and G2/M‑phase arrest in a dose‑ and time‑dependent manner. Corresponding with the above results, the expression levels of GLUT‑1 were significantly decreased following treatment in a dose- and time-dependent manner. These results suggest that the inhibition of ACC-2 cell growth by apigenin may be due to the decreased expression of GLUT-1.

  18. Fear inhibition in high trait anxiety.

    Science.gov (United States)

    Kindt, Merel; Soeter, Marieke

    2014-01-01

    Trait anxiety is recognized as an individual risk factor for the development of anxiety disorders but the neurobiological mechanisms remain unknown. Here we test whether trait anxiety is associated with impaired fear inhibition utilizing the AX+/BX- conditional discrimination procedure that allows for the independent evaluation of startle fear potentiation and inhibition of fear. Sixty undergraduate students participated in the study--High Trait Anxious: n = 28 and Low Trait Anxious: n = 32. We replicated earlier findings that a transfer of conditioned inhibition for startle responses requires contingency awareness. However, contrary to the fear inhibition hypothesis, our data suggest that high trait anxious individuals show a normal fear inhibition of conditioned startle responding. Only at the cognitive level the high trait anxious individuals showed evidence for impaired inhibitory learning of the threat cue. Together with other findings where impaired fear inhibition was only observed in those PTSD patients who were either high on hyperarousal symptoms or with current anxiety symptoms, we question whether impaired fear inhibition is a biomarker for the development of anxiety disorders.

  19. Helichrysum and grapefruit extracts inhibit carbohydrate digestion and absorption, improving postprandial glucose levels and hyperinsulinemia in rats.

    Science.gov (United States)

    de la Garza, Ana Laura; Etxeberria, Usune; Lostao, María Pilar; San Román, Belén; Barrenetxe, Jaione; Martínez, J Alfredo; Milagro, Fermín I

    2013-12-11

    Several plant extracts rich in flavonoids have been reported to improve hyperglycemia by inhibiting digestive enzyme activities and SGLT1-mediated glucose uptake. In this study, helichrysum ( Helichrysum italicum ) and grapefruit ( Citrus × paradisi ) extracts inhibited in vitro enzyme activities. The helichrysum extract showed higher inhibitory activity of α-glucosidase (IC50 = 0.19 mg/mL) than α-amylase (IC50 = 0.83 mg/mL), whereas the grapefruit extract presented similar α-amylase and α-glucosidase inhibitory activities (IC50 = 0.42 mg/mL and IC50 = 0.41 mg/mL, respectively). Both extracts reduced maltose digestion in noneverted intestinal sacs (57% with helichrysum and 46% with grapefruit). Likewise, both extracts inhibited SGLT1-mediated methylglucoside uptake in Caco-2 cells in the presence of Na(+) (56% of inhibition with helichrysum and 54% with grapefruit). In vivo studies demonstrated that helichrysum decreased blood glucose levels after an oral maltose tolerance test (OMTT), and both extracts reduced postprandial glucose levels after the oral starch tolerance test (OSTT). Finally, both extracts improved hyperinsulinemia (31% with helichrysum and 50% with grapefruit) and HOMA index (47% with helichrysum and 54% with grapefruit) in a dietary model of insulin resistance in rats. In summary, helichrysum and grapefruit extracts improve postprandial glycemic control in rats, possibly by inhibiting α-glucosidase and α-amylase enzyme activities and decreasing SGLT1-mediated glucose uptake.

  20. Glucose uptake and growth of glucose-limited chemostat cultures of Aspergillus niger and a disruptant lacking MstA, a high-affinity glucose transporter

    DEFF Research Database (Denmark)

    Jørgensen, Thomas R; vanKuyk, Patricia A; Poulsen, Bjarne R

    2007-01-01

    This is a study of high-affinity glucose uptake in Aspergillus niger and the effect of disruption of a high-affinity monosaccharide-transporter gene, mstA. The substrate saturation constant (K(s)) of a reference strain was about 15 microM in glucose-limited chemostat culture. Disruption of mst......-affinity uptake system of A. niger. The mstA disruptant and a reference strain were cultivated in glucose-limited chemostat cultures at low, intermediate and high dilution rate (D=0.07 h(-1), 0.14 h(-1) and 0.20 h(-1)). Mycelium harvested from steady-state cultures was subjected to glucose uptake assays...

  1. Involvement of AP-1 in p38MAPK signaling pathway in osteoblast apoptosis induced by high glucose.

    Science.gov (United States)

    Feng, Z P; Deng, H C; Jiang, R; Du, J; Cheng, D Y

    2015-04-10

    We investigated the effect of p38MAPK/AP-1 (activator protein-1) signaling on the apoptosis of osteoblasts induced by high glucose. A lentivirus vector of small hairpin RNA (shRNA) targeting p38MAPK was constructed in vitro. Osteoblasts MC3T3-E1 cultured in vitro were treated with vehicle, high glucose, p38MAPK-shRNA transfection, p38MAPK inhibitor, and unrelated shRNA transfection. Apoptosis, protein levels of p38MAPK, and activities of AP-1 in MC3T3-E1 osteoblasts were measured using TUNEL and flow cytometry, Western blot analysis, and an electrophoretic mobility shift assay. Compared with the vehicle group, high glucose induced apoptosis of MC3T3-E1 osteoblasts and activated p38MAPK and AP-1. p38MAPK-shRNA transfection blocked the effect of high glucose stimulation, and the p38MAPK inhibitor showed similar effects as those observed in p38MAPK transfection. Unrelated shRNA had no effect on these changes in MC3T3-E1 osteoblasts induced by high glucose. Therefore, our results suggest that p38MAPK-shRNA reduce apoptosis of MC3T3-E1 osteoblasts induced by high glucose by inhibiting the p38MAPK-AP-1 signaling pathway.

  2. Protective role of morin, a flavonoid, against high glucose induced oxidative stress mediated apoptosis in primary rat hepatocytes.

    Directory of Open Access Journals (Sweden)

    Radhika Kapoor

    Full Text Available Apoptosis is an early event of liver damage in diabetes and oxidative stress has been linked to accelerate the apoptosis in hepatocytes. Therefore, the compounds that can scavenge ROS may confer regulatory effects on high-glucose induced apoptosis. In the present study, primary rat hepatocytes were exposed to high concentration (40 mM of glucose. At this concentration decreased cell viability and enhanced ROS generation was observed. Depleted antioxidant status of hepatocytes under high glucose stress was also observed as evident from transcriptional level and activities of antioxidant enzymes. Further, mitochondrial depolarisation was accompanied by the loss of mitochondrial integrity and altered expression of Bax and Bcl-2. Increased translocation of apoptotic proteins like AIF (Apoptosis inducing factor & Endo-G (endonuclease-G from its resident place mitochondria to nucleus was also observed. Cyt-c residing in the inter-membrane space of mitochondria also translocated to cytoplasm. These apoptotic proteins initiated caspase activation, DNA fragmentation, chromatin condensation, increased apoptotic DNA content in glucose treated hepatocytes, suggesting mitochondria mediated apoptotic mode of cell death. Morin, a dietary flavonoid from Psidium guajava was effective in increasing the cell viability and decreasing the ROS level. It maintained mitochondrial integrity, inhibited release of apoptotic proteins from mitochondria, prevented DNA fragmentation, chromatin condensation and hypodiploid DNA upon exposure to high glucose. This study confirms the capacity of dietary flavonoid Morin in regulating apoptosis induced by high glucose via mitochondrial mediated pathway through intervention of oxidative stress.

  3. High Blood Glucose: What It Means and How To Treat It

    Science.gov (United States)

    ... leave this field empty High Blood Glucose: What It Means and How To Treat It What is high blood glucose? People who do ... glucose, also called 'hyperglycemia', is considered "high" when it is 160 mg/dl or above your individual ...

  4. Oxidative stress plays a role in high glucose-induced activation of pancreatic stellate cells

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Gyeong Ryul; Lee, Esder; Chun, Hyun-Ji; Yoon, Kun-Ho; Ko, Seung-Hyun; Ahn, Yu-Bae; Song, Ki-Ho, E-mail: kihos@catholic.ac.kr

    2013-09-20

    Highlights: •High glucose increased production of reactive oxygen species in cultured pancreatic stellate cells. •High glucose facilitated the activation of these cells. •Antioxidant treatment attenuated high glucose-induced activation of these cells. -- Abstract: The activation of pancreatic stellate cells (PSCs) is thought to be a potential mechanism underlying islet fibrosis, which may contribute to progressive β-cell failure in type 2 diabetes. Recently, we demonstrated that antioxidants reduced islet fibrosis in an animal model of type 2 diabetes. However, there is no in vitro study demonstrating that high glucose itself can induce oxidative stress in PSCs. Thus, PSCs were isolated and cultured from Sprague Dawley rats, and treated with high glucose for 72 h. High glucose increased the production of reactive oxygen species. When treated with high glucose, freshly isolated PSCs exhibited myofibroblastic transformation. During early culture (passage 1), PSCs treated with high glucose contained an increased number of α-smooth muscle actin-positive cells. During late culture (passages 2–5), PSCs treated with high glucose exhibited increases in cell proliferation, the expression of fibronectin and connective tissue growth factor, release of interleukin-6, transforming growth factor-β and collagen, and cell migration. Finally, the treatment of PSCs with high glucose and antioxidants attenuated these changes. In conclusion, we demonstrated that high glucose increased oxidative stress in primary rat PSCs, thereby facilitating the activation of these cells, while antioxidant treatment attenuated high glucose-induced PSC activation.

  5. High glucose induces inflammatory cytokine through protein kinase C-induced toll-like receptor 2 pathway in gingival fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Shao-Yun, E-mail: jiangshaoyun@yahoo.com [School of Dentistry, Tianjin Medical University, 12 Qi Xiang Tai Street, Heping District, Tianjin 300070 (China); Wei, Cong-Cong; Shang, Ting-Ting; Lian, Qi; Wu, Chen-Xuan [School of Dentistry, Tianjin Medical University, 12 Qi Xiang Tai Street, Heping District, Tianjin 300070 (China); Deng, Jia-Yin, E-mail: yazhou2991@126.com [School of Dentistry, Tianjin Medical University, 12 Qi Xiang Tai Street, Heping District, Tianjin 300070 (China)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer High glucose significantly induced TLR2 expression in gingival fibroblasts. Black-Right-Pointing-Pointer High glucose increased NF-{kappa}B p65 nuclear activity, IL-1{beta} and TNF-{alpha} levels. Black-Right-Pointing-Pointer PKC-{alpha}/{delta}-TLR2 pathway is involved in periodontal inflammation under high glucose. -- Abstract: Toll-like receptors (TLRs) play a key role in innate immune response and inflammation, especially in periodontitis. Meanwhile, hyperglycemia can induce inflammation in diabetes complications. However, the activity of TLRs in periodontitis complicated with hyperglycemia is still unclear. In the present study, high glucose (25 mmol/l) significantly induced TLR2 expression in gingival fibroblasts (p < 0.05). Also, high glucose increased nuclear factor kappa B (NF-{kappa}B) p65 nuclear activity, tumor necrosis factor-{alpha} (TNF-{alpha}) and interleukin-l{beta} (IL-1{beta}) levels. Protein kinase C (PKC)-{alpha} and {delta} knockdown with siRNA significantly decreased TLR2 and NF-{kappa}B p65 expression (p < 0.05), whereas inhibition of PKC-{beta} had no effect on TLR2 and NF-{kappa}B p65 under high glucose (p < 0.05). Additional studies revealed that TLR2 knockdown significantly abrogated high-glucose-induced NF-{kappa}B expression and inflammatory cytokine secretion. Collectively, these data suggest that high glucose stimulates TNF-{alpha} and IL-1{beta} secretion via inducing TLR2 through PKC-{alpha} and PKC-{delta} in human gingival fibroblasts.

  6. [High glucose dialysate enhances peritoneal fibrosis through upregulating glucose transporters GLUT1 and SGLT1].

    Science.gov (United States)

    Hong, Mengqi; Nie, Zhenyu; Chen, Zhengyue; Yu, Xiongwei; Bao, Beiyan

    2016-05-25

    Objective: To investigate the role of glucose transporter 1 (GLUT1) and sodium-glucose cotransporter 1 (SGLT1) in high glucose dialysate-induced peritoneal fibrosis. Methods: Thirty six male SD rats were randomly divided into 6 groups (6 in each):normal control group, sham operation group, peritoneal dialysis group (PD group), PD+phloretin group (PD+T group), PD+phlorizin group (PD+Z group), PD+phloretin+phlorizin group (PD+T+Z group). Rat model of uraemia was established using 5/6 nephrotomy, and 2.5% dextrose peritoneal dialysis solution was used in peritoneal dialysis. Peritoneal equilibration test was performed 24 h after dialysis to evaluate transport function of peritoneum in rats; HE staining was used to observe the morphology of peritoneal tissue; and immunohistochemistry was used to detect the expression of GLUT1, SGLT1, TGF-β1 and connective tissue growth factor (CTGF) in peritoneum. Human peritoneal microvascular endothelial cells (HPECs) were divided into 5 groups:normal control group, peritoneal dialysis group (PD group), PD+phloretin group (PD+T group), PD+phlorezin group (PD+Z group), and PD+phloretin+phlorezin group (PD+T+Z group). Real time PCR and Western blotting were used to detect mRNA and protein expressions of GLUT1, SGLT1, TGF-β1, CTGF in peritoneal membrane and HPECs. Results:In vivo, compared with sham operation group, rats in PD group had thickened peritoneum, higher ultrafiltration volume, and the mRNA and protein expressions of GLUT1, SGLT1, CTGF, TGF-β1 were significantly increased (all P<0.05); compared with PD group, thickened peritoneum was attenuated, and the mRNA and protein expressions of GLUT1, SGLT1, CTGF, TGF-β1 were significantly decreased in PD+T, PD+Z and PD+T+Z groups (all P<0.05). Pearson's correlation analysis showed that the expressions of GLUT1, SGLT1 in peritoneum were positively correlated with the expressions of TGF-β1 and CTGF (all P<0.05). In vitro, the mRNA and protein expressions of GLUT1, SGLT1, TGF-β1

  7. Intraportal infusion of ghrelin could inhibit glucose-stimulated GLP-1 secretion by enteric neural net in Wistar rat.

    Science.gov (United States)

    Zhang, Xiyao; Li, Wensong; Li, Ping; Chang, Manli; Huang, Xu; Li, Qiang; Cui, Can

    2014-01-01

    As a regulator of food intake and energy metabolism, the role of ghrelin in glucose metabolism is still not fully understood. In this study, we determined the in vivo effect of ghrelin on incretin effect. We demonstrated that ghrelin inhibited the glucose-stimulated release of glucagon-like peptide-1 (GLP-1) when infused into the portal vein of Wistar rat. Hepatic vagotomy diminished the inhibitory effect of ghrelin on glucose-stimulated GLP-1 secretion. In addition, phentolamine, a nonselective α receptor antagonist, could recover the decrease of GLP-1 release induced by ghrelin infusion. Pralmorelin (an artificial growth hormone release peptide) infusion into the portal vein could also inhibit the glucose-stimulated release of GLP-1. And growth hormone secretagogue receptor antagonist, [D-lys3]-GHRP-6, infusion showed comparable increases of glucose stimulated GLP-1 release compared to ghrelin infusion into the portal vein. The data showed that intraportal infusion of ghrelin exerted an inhibitory effect on GLP-1 secretion through growth hormone secretagogue receptor 1α (GHS1α receptor), which indicated that the downregulation of ghrelin secretion after food intake was necessary for incretin effect. Furthermore, our results suggested that the enteric neural net involved hepatic vagal nerve and sympathetic nerve mediated inhibition effect of ghrelin on incretin effect.

  8. Intraportal Infusion of Ghrelin Could Inhibit Glucose-Stimulated GLP-1 Secretion by Enteric Neural Net in Wistar Rat

    Directory of Open Access Journals (Sweden)

    Xiyao Zhang

    2014-01-01

    Full Text Available As a regulator of food intake and energy metabolism, the role of ghrelin in glucose metabolism is still not fully understood. In this study, we determined the in vivo effect of ghrelin on incretin effect. We demonstrated that ghrelin inhibited the glucose-stimulated release of glucagon-like peptide-1 (GLP-1 when infused into the portal vein of Wistar rat. Hepatic vagotomy diminished the inhibitory effect of ghrelin on glucose-stimulated GLP-1 secretion. In addition, phentolamine, a nonselective α receptor antagonist, could recover the decrease of GLP-1 release induced by ghrelin infusion. Pralmorelin (an artificial growth hormone release peptide infusion into the portal vein could also inhibit the glucose-stimulated release of GLP-1. And growth hormone secretagogue receptor antagonist, [D-lys3]-GHRP-6, infusion showed comparable increases of glucose stimulated GLP-1 release compared to ghrelin infusion into the portal vein. The data showed that intraportal infusion of ghrelin exerted an inhibitory effect on GLP-1 secretion through growth hormone secretagogue receptor 1α (GHS1α receptor, which indicated that the downregulation of ghrelin secretion after food intake was necessary for incretin effect. Furthermore, our results suggested that the enteric neural net involved hepatic vagal nerve and sympathetic nerve mediated inhibition effect of ghrelin on incretin effect.

  9. High-normal fasting glucose levels are associated with increased prevalence of impaired glucose tolerance in obese children.

    Science.gov (United States)

    Grandone, A; Amato, A; Luongo, C; Santoro, N; Perrone, L; del Giudice, E Miraglia

    2008-12-01

    The natural history of impaired glucose tolerance (IGT) and Type 2 diabetes among obese children is not clear. Although the cut-off for impaired fasting glucose (IFG) has recently been changed from 110 (6.1 mmol/l) to 100 mg/dl (5.6 mmol/l), it does not seem a reliable way to find all subjects with impaired glucose homeostasis. The aim of our study was to determine whether high-normal fasting glucose level could predict the occurrence of IGT and metabolic syndrome. Three hundred and twenty-three Italian obese children and adolescents were included in the study (176 females, mean age 11+/-2.9 yr; mean body mass index z-score: 3+/-0.6). Waist circumference, serum glucose, insulin, triglyceride, cholesterol HDL, blood pressure were evaluated and an oral glucose tolerance test (OGTT) was performed. The prevalence of IFG and IGT were respectively 1.5% (5 subjects) and 5% (18 patients); no diabetic patients were found. Metabolic syndrome was diagnosed in 20% of patients. Fasting glycemia values youths. Interestingly high-normal fasting plasma glucose levels constitute an independent risk factor for IGT among obese children and adolescents; therefore, this very easy-to-use parameter may help to identify obese patients at increased risk of diabetes or at least could suggest in which subjects to perform an OGTT.

  10. Myricitrin Attenuates High Glucose-Induced Apoptosis through Activating Akt-Nrf2 Signaling in H9c2 Cardiomyocytes

    Directory of Open Access Journals (Sweden)

    Bin Zhang

    2016-07-01

    Full Text Available Hyperglycemia, as well as diabetes mellitus, has been shown to trigger cardiac cell apoptosis. We have previously demonstrated that myricitrin prevents endothelial cell apoptosis. However, whether myricitrin can attenuate H9c2 cell apoptosis remains unknown. In this study, we established an experiment model in H9c2 cells exposed to high glucose. We tested the hypothesis that myricitrin may inhibit high glucose (HG-induced cardiac cell apoptosis as determined by TUNEL staining. Furthermore, myricitrin promoted antioxidative enzyme production, suppressed high glucose-induced reactive oxygen species (ROS production and decreased mitochondrial membrane potential (MMP in H9c2 cells. This agent significantly inhibited apoptotic protein expression, activated Akt and facilitated the transcription of NF-E2-related factor 2 (Nrf2-mediated protein (heme oxygenase-1 (HO-1 and quinone oxidoreductase 1 (NQO-1 expression as determined by Western blotting. Significantly, an Akt inhibitor (LY294002 or HO-1 inhibitor (ZnPP not only inhibited myricitrin-induced HO-1/NQO-1 upregulation but also alleviated its anti-apoptotic effects. In summary, these observations demonstrate that myricitrin activates Nrf2-mediated anti-oxidant signaling and attenuates H9c2 cell apoptosis induced by high glucose via activation of Akt signaling.

  11. Effects of Berberine on Amelioration of Hyperglycemia and Oxidative Stress in High Glucose and High Fat Diet-Induced Diabetic Hamsters In Vivo

    Directory of Open Access Journals (Sweden)

    Cong Liu

    2015-01-01

    Full Text Available This study investigated the effects of berberine on amelioration of hyperglycemia and hyperlipidemia and the mechanism involved in high glucose and high fat diet-induced diabetic hamsters. Golden hamsters fed with high glucose and high fat diet were medicated with metformin, simvastatin, and low or high dose of berberine (50 and 100 mg·kg−1 for 6 weeks. The results showed that the body weights were significantly lower in berberine-treated groups than control group. Histological analyses revealed that the treatment of berberine inhibited hepatic fat accumulation. Berberine significantly reduced plasma total cholesterol, triglyceride, free fatty acid, low density lipoprotein cholesterol, malondialdehyde, thiobarbituric acid-reactive substance, and 8-isoprostane level but significantly increased plasma superoxide dismutase activity. Glucose and insulin levels were significantly reduced in metformin and berberine-treated groups. Glucose tolerance tests documented that berberine-treated mice were more glucose tolerant. Berberine treatment increased expression of skeletal muscle glucose transporter 4 mRNA and significantly decreased liver low density lipoprotein receptor mRNA expression. The study suggested that berberine was effective in lowering blood glucose and lipids levels, reducing the body weight, and alleviating the oxidative stress in diabetic hamsters, which might be beneficial in reducing the cardiovascular risk factors in diabetes.

  12. 1, 25(OH)2D3 protects β cell against high glucose-induced apoptosis through mTOR suppressing.

    Science.gov (United States)

    Yang, Zesong; Liu, Fang; Qu, Hua; Wang, Hang; Xiao, Xiaoqiu; Deng, Huacong

    2015-10-15

    Diabetes mellitus is a leading cause of death and disability worldwide, which presents a serious public health crisis in China nowadays. It has been well recognized that excessive β-cell apoptosis is the key pathogenesis of diabetes, of which the mammalian target of rapamycin (mTOR) serves as the critical signaling pathway. Emerging evidence indicates that vitamin D deficiency acts as a potential risk factor for diabetes. The present study aims to test the hypothesis that 1 alpha, 25-dihydroxyvitamin D(3) [1, 25(OH)2D3] can inhibit β-cell apoptosis via the suppression of mTOR signaling pathway. β-cells (INS-1) were cultured in the context of normal glucose or high glucose media with or without 1, 25(OH)2D3 treatment. β-cell apoptosis was evaluated by inverted fluorescence microscope, flow cytometry and electron microscope, respectively. Quantitative RT-PCR and Western blotting were performed to assess the possible perturbations in mTOR signaling pathway. High glucose significantly increased β-cell apoptosis. Of importance, RT-PCR and Western blotting demonstrated that high glucose inhibited DNA-damage-inducible transcript 4 (DDIT4) and TSC1/TSC2, up-regulated Rheb/mTOR/p70S6K and enhanced expression of the apoptosis regulating proteins, such as phospho-Bcl-2, cytochrome C and cleaved caspase. Interestingly, 1, 25(OH)2D3 treatment reversed high glucose induced pathological changes in mTOR signaling pathway, restored expression of DDIT4 and TSC1/TSC2, blocked aberrant up-regulation of Rheb/mTOR/p70S6K and the apoptosis regulating proteins, and effectively inhibited β-cell apoptosis. Therefore, 1, 25(OH)2D3 treatment can effectively protects β cell against high glucose-induced apoptosis mainly via the suppression of mTOR signaling pathway, which may be considered as a potential therapy for patients with diabetes.

  13. Amelioration by glucose-6-phosphate and NADP of potato glycoalkaloid inhibition in cell, enzyme and liposome assays.

    Science.gov (United States)

    Roddick, J G; Leonard, A L

    1999-05-01

    Lysis of human erythrocytes by 20 microM chaconine was reduced by 0.5 mM glucose-6-phosphate (G6P) and NADP. Both compounds caused approximately 50% inhibition of haemolysis at 1 mM. Glucose, glucose-1-phosphate, rhamnose, galactose and galactose-6-phosphate were ineffective; NAD was effective, although not to the extent of NADP. Of the tested sugars, only G6P reduced solanine-induced haemolysis. G6P also reduced the synergistic haemolytic action of solanine and chaconine in combination. G6P and NADP at or above 5 mM antagonised chaconine-induced betanin loss from excised red beet root discs; NADP was more effective than G6P. Disruption of PC/cholesterol liposomes by chaconine and inhibition of acetylcholinesterase by chaconine or solanine, were unaffected by up to 10 mM NADP or 50 mM G6P.

  14. The Na+/Glucose Cotransporter Inhibitor Canagliflozin Activates AMPK by Inhibiting Mitochondrial Function and Increasing Cellular AMP Levels.

    Science.gov (United States)

    Hawley, Simon A; Ford, Rebecca J; Smith, Brennan K; Gowans, Graeme J; Mancini, Sarah J; Pitt, Ryan D; Day, Emily A; Salt, Ian P; Steinberg, Gregory R; Hardie, D Grahame

    2016-09-01

    Canagliflozin, dapagliflozin, and empagliflozin, all recently approved for treatment of type 2 diabetes, were derived from the natural product phlorizin. They reduce hyperglycemia by inhibiting glucose reuptake by sodium/glucose cotransporter (SGLT) 2 in the kidney, without affecting intestinal glucose uptake by SGLT1. We now report that canagliflozin also activates AMPK, an effect also seen with phloretin (the aglycone breakdown product of phlorizin), but not to any significant extent with dapagliflozin, empagliflozin, or phlorizin. AMPK activation occurred at canagliflozin concentrations measured in human plasma in clinical trials and was caused by inhibition of Complex I of the respiratory chain, leading to increases in cellular AMP or ADP. Although canagliflozin also inhibited cellular glucose uptake independently of SGLT2, this did not account for AMPK activation. Canagliflozin also inhibited lipid synthesis, an effect that was absent in AMPK knockout cells and that required phosphorylation of acetyl-CoA carboxylase (ACC) 1 and/or ACC2 at the AMPK sites. Oral administration of canagliflozin activated AMPK in mouse liver, although not in muscle, adipose tissue, or spleen. Because phosphorylation of ACC by AMPK is known to lower liver lipid content, these data suggest a potential additional benefit of canagliflozin therapy compared with other SGLT2 inhibitors. © 2016 by the American Diabetes Association.

  15. Intestinal Sodium Glucose Cotransporter 1 Inhibition Enhances Glucagon-Like Peptide-1 Secretion in Normal and Diabetic Rodents.

    Science.gov (United States)

    Oguma, Takahiro; Nakayama, Keiko; Kuriyama, Chiaki; Matsushita, Yasuaki; Yoshida, Kumiko; Hikida, Kumiko; Obokata, Naoyuki; Tsuda-Tsukimoto, Minoru; Saito, Akira; Arakawa, Kenji; Ueta, Kiichiro; Shiotani, Masaharu

    2015-09-01

    The sodium glucose cotransporter (SGLT) 1 plays a major role in glucose absorption and incretin hormone release in the gastrointestinal tract; however, the impact of SGLT1 inhibition on plasma glucagon-like peptide-1 (GLP-1) levels in vivo is controversial. We analyzed the effects of SGLT1 inhibitors on GLP-1 secretion in normoglycemic and hyperglycemic rodents using phloridzin, CGMI [3-(4-cyclopropylphenylmethyl)-1-(β-d-glucopyranosyl)-4-methylindole], and canagliflozin. These compounds are SGLT2 inhibitors with moderate SGLT1 inhibitory activity, and their IC50 values against rat SGLT1 and mouse SGLT1 were 609 and 760 nM for phloridzin, 39.4 and 41.5 nM for CGMI, and 555 and 613 nM for canagliflozin, respectively. Oral administration of these inhibitors markedly enhanced and prolonged the glucose-induced plasma active GLP-1 (aGLP-1) increase in combination treatment with sitagliptin, a dipeptidyl peptidase-4 (DPP4) inhibitor, in normoglycemic mice and rats. CGMI, the most potent SGLT1 inhibitor among them, enhanced glucose-induced, but not fat-induced, plasma aGLP-1 increase at a lower dose compared with canagliflozin. Both CGMI and canagliflozin delayed intestinal glucose absorption after oral administration in normoglycemic rats. The combined treatment of canagliflozin and a DPP4 inhibitor increased plasma aGLP-1 levels and improved glucose tolerance compared with single treatment in both 8- and 13-week-old Zucker diabetic fatty rats. These results suggest that transient inhibition of intestinal SGLT1 promotes GLP-1 secretion by delaying glucose absorption and that concomitant inhibition of intestinal SGLT1 and DPP4 is a novel therapeutic option for glycemic control in type 2 diabetes mellitus. Copyright © 2015 by The American Society for Pharmacology and Experimental Therapeutics.

  16. Quercetin and epigallocatechin gallate inhibit glucose uptake and metabolism by breast cancer cells by an estrogen receptor-independent mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Moreira, Liliana, E-mail: lilianam87@gmail.com [Department of Biochemistry (U38-FCT), Faculty of Medicine of University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto (Portugal); Araújo, Isabel, E-mail: isa.araujo013@gmail.com [Department of Biochemistry (U38-FCT), Faculty of Medicine of University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto (Portugal); Costa, Tito, E-mail: tito.fmup16@gmail.com [Department of Biochemistry (U38-FCT), Faculty of Medicine of University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto (Portugal); Correia-Branco, Ana, E-mail: ana.clmc.branco@gmail.com [Department of Biochemistry (U38-FCT), Faculty of Medicine of University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto (Portugal); Faria, Ana, E-mail: anafaria@med.up.pt [Department of Biochemistry (U38-FCT), Faculty of Medicine of University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto (Portugal); Chemistry Investigation Centre (CIQ), Faculty of Sciences of University of Porto, Rua Campo Alegre, 4169-007 Porto (Portugal); Faculty of Nutrition and Food Sciences of University of Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Martel, Fátima, E-mail: fmartel@med.up.pt [Department of Biochemistry (U38-FCT), Faculty of Medicine of University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto (Portugal); Keating, Elisa, E-mail: keating@med.up.pt [Department of Biochemistry (U38-FCT), Faculty of Medicine of University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319 Porto (Portugal)

    2013-07-15

    In this study we characterized {sup 3}H-2-deoxy-D-glucose ({sup 3}H -DG) uptake by the estrogen receptor (ER)-positive MCF7 and the ER-negative MDA-MB-231 human breast cancer cell lines and investigated the effect of quercetin (QUE) and epigallocatechin gallate (EGCG) upon {sup 3}H-DG uptake, glucose metabolism and cell viability and proliferation. In both MCF7 and MDA-MB-231 cells {sup 3}H-DG uptake was (a) time-dependent, (b) saturable with similar capacity (V{sub max}) and affinity (K{sub m}), (c) potently inhibited by cytochalasin B, an inhibitor of the facilitative glucose transporters (GLUT), (d) sodium-independent and (e) slightly insulin-stimulated. This suggests that {sup 3}H-DG uptake by both cell types is mediated by members of the GLUT family, including the insulin-responsive GLUT4 or GLUT12, while being independent of the sodium-dependent glucose transporter (SGLT1). QUE and EGCG markedly and concentration-dependently inhibited {sup 3}H-DG uptake by MCF7 and by MDA-MB-231 cells, and both compounds blocked lactate production by MCF7 cells. Additionally, a 4 h-treatment with QUE or EGCG decreased MCF7 cell viability and proliferation, an effect that was more potent when glucose was available in the extracellular medium. Our results implicate QUE and EGCG as metabolic antagonists in breast cancer cells, independently of estrogen signalling, and suggest that these flavonoids could serve as therapeutic agents/adjuvants even for ER-negative breast tumors. -- Highlights: • Glucose uptake by MCF7 and MDA-MB-231 cells is mainly mediated by GLUT1. • QUE and EGCG inhibit cellular glucose uptake thus abolishing the Warburg effect. • This process induces cytotoxicity and proliferation arrest in MCF7 cells. • The flavonoids’ effects are independent of estrogen receptor signalling.

  17. High glucose increases Cdk5 activity in podocytes via transforming growth factor-β1 signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yue [Department of Diagnostics, Hebei Medical University, Shijiazhuang 050017 (China); Li, Hongbo; Hao, Jun [Department of Pathology, Hebei Medical University, Shijiazhuang 050017 (China); Zhou, Yi [Department of Neurology, the Second Hospital of Hebei Medical University, Shijiazhuang 050000 (China); Liu, Wei, E-mail: lwei929@126.com [Department of Pathology, Hebei Medical University, Shijiazhuang 050017 (China)

    2014-08-15

    Podocytes are highly specialized and terminally differentiated glomerular cells that play a vital role in the development and progression of diabetic nephropathy (DN). Cyclin-dependent kinase 5 (Cdk5), who is an atypical but essential member of the Cdk family of proline-directed serine/threonine kinases, has been shown as a key regulator of podocyte differentiation, proliferation and morphology. Our previous studies demonstrated that the expression of Cdk5 was significantly increased in podocytes of diabetic rats, and was closely related with podocyte injury of DN. However, the mechanisms of how expression and activity of Cdk5 are regulated under the high glucose environment have not yet been fully elucidated. In this study, we showed that high glucose up-regulated the expression of Cdk5 and its co-activator p35 with a concomitant increase in Cdk5 kinase activity in conditionally immortalized mouse podocytes in vitro. When exposed to 30 mM glucose, transforming growth factor-β1 (TGF-β1) was activated. Most importantly, we found that SB431542, the Tgfbr1 inhibitor, significantly decreased the expression of Cdk5 and p35 and Cdk5 kinase activity in high glucose-treated podocytes. Moreover, high glucose increased the expression of early growth response-1 (Egr-1) via TGF-β1-ERK1/2 pathway in podocytes and inhibition of Egr-1 by siRNA decreased p35 expression and Cdk5 kinase activity. Furthermore, inhibition of Cdk5 kinase activity effectively alleviated podocyte apoptosis induced by high glucose or TGF-β1. Thus, the TGF-β1-ERK1/2-Egr-1 signaling pathway may regulate the p35 expression and Cdk5 kinase activity in high glucose-treated podocytes, which contributes to podocyte injury of DN. - Highlights: • HG up-regulated the expression of Cdk5 and p35, and Cdk5 activity in podocytes. • HG activated TGF-β1 pathway and SB431542 inhibited Cdk5 expression and activity. • HG increased the expression of Egr-1 via TGF-β1-ERK1/2 pathway. • Inhibition of Egr-1

  18. Lipopolysaccharide (LPS) and tumor necrosis factor alpha (TNFα) blunt the response of Neuropeptide Y/Agouti-related peptide (NPY/AgRP) glucose inhibited (GI) neurons to decreased glucose.

    Science.gov (United States)

    Hao, Lihong; Sheng, Zhenyu; Potian, Joseph; Deak, Adam; Rohowsky-Kochan, Christine; Routh, Vanessa H

    2016-10-01

    A population of Neuropeptide Y (NPY) neurons which co-express Agouti-related peptide (AgRP) in the arcuate nucleus of the hypothalamus (ARC) are inhibited at physiological levels of brain glucose and activated when glucose levels decline (e.g. glucose-inhibited or GI neurons). Fasting enhances the activation of NPY/AgRP-GI neurons by low glucose. In the present study we tested the hypothesis that lipopolysaccharide (LPS) inhibits the enhanced activation of NPY/AgRP-GI neurons by low glucose following a fast. Mice which express green fluorescent protein (GFP) on their NPY promoter were used to identify NPY/AgRP neurons. Fasting for 24h and LPS injection decreased blood glucose levels. As we have found previously, fasting increased c-fos expression in NPY/AgRP neurons and increased the activation of NPY/AgRP-GI neurons by decreased glucose. As we predicted, LPS blunted these effects of fasting at the 24h time point. Moreover, the inflammatory cytokine tumor necrosis factor alpha (TNFα) blocked the activation of NPY/AgRP-GI neurons by decreased glucose. These data suggest that LPS and TNFα may alter glucose and energy homeostasis, in part, due to changes in the glucose sensitivity of NPY/AgRP neurons. Interestingly, our findings also suggest that NPY/AgRP-GI neurons use a distinct mechanism to sense changes in extracellular glucose as compared to our previous studies of GI neurons in the adjacent ventromedial hypothalamic nucleus.

  19. Inhibition of oxidative stress in high glucose-induced proximal tubule epithelial cells by breviscapine%灯盏花素抑制高糖诱导大鼠近端小管上皮细胞的氧化应激

    Institute of Scientific and Technical Information of China (English)

    杜飞; 高原; 姚君; 王兴红

    2011-01-01

    ( P < 0 .01) and high dose group ( P < 0 .01) .The level of H2O2 was significantly increased in HG group of PTEC ( P < 0 .01) .The level of H2O2 in low dose group was still higher than normal control group ( P < 0 .05) ,however ,It was significantly decreased in middle ( P < 0 .05) and high dose group ( P < 0 .05) .The level of CAT was significantly decreased in HG group ( P < 0 .01) .It was decreased in low dose group( P < 0 .05) ,otherwise significantly increased in high dose group ( P < 0 .01) .The level of GSH was significantly decreased in HG group ( P < 0 .05) .It was decreased in low dose group ( P < 0 .05) ,whereas significantly increased in middle ( P < 0 .05) and high dose group ( P < 0 .01) .Conclusion  The oxidative stress may be inhibited by breviscapine in high glucose-induced primary PTEC .Renal protective mechanism of breviscapine may be ,at leastly ,correlated with inhibition oxidative stress in PTEC .

  20. The Biological Behaviors of Rat Dermal Fibroblasts Can Be Inhibited by High Levels of MMP9

    Directory of Open Access Journals (Sweden)

    Sheng-Neng Xue

    2012-01-01

    Full Text Available Aims. To explore the effects of the high expression of MMP9 on biological behaviors of fibroblasts. Methods. High glucose and hyperhomocysteine were used to induce MMP9 expression in skin fibroblasts. Cell proliferation was detected by flow cytometry and cell viability by CCK-8. ELISA assay was used to detect collagen (hydroxyproline secretion. Scratch test was employed to evaluate horizontal migration of cells and transwell method to evaluate vertical migration of cells. Results. The mRNA and protein expressions of MMP9 and its protease activity were significantly higher in cells treated with high glucose and hyperhomocysteine than those in control group. At the same time, the S-phase cell ratio, proliferation index, cell viability, collagen (hydroxyproline secretion, horizontal migration rate, and the number of vertical migration cells decreased in high-glucose and hyperhomocysteine-treated group. Tissue inhibitor of metalloproteinase 1 (TIMP1, which inhibits the activity of MMP9, recovered the above biological behaviors. Conclusions. High expression of MMP9 in skin fibroblasts could be induced by cultureing in high glucose and hyperhomocysteine medium, which inhibited cell biological behaviors. Inhibitions could be reversed by TIMP1. The findings suggested that MMP9 deters the healing of diabetic foot ulcers by inhibiting the biological behaviors of fibroblasts.

  1. Effects of endomorphins on human umbilical vein endothelial cells under high glucose.

    Science.gov (United States)

    Liu, Jing; Wei, Suhong; Tian, Limin; Yan, Liping; Guo, Qian; Ma, Xiaoqin

    2011-01-01

    The endomorphin-1 (EM1) and endomorphin-2 (EM2) are endogenous opioid peptides, which modulate extensive bioactivities such as pain, cardiovascular responses, immunological responses and so on. The present study was undertaken to investigate the effects of EM1/EM2 on the primary cultured human umbilical vein endothelial cells (HUVECs) damaged by high glucose. PI AnnexinV-FITC detection was performed to evaluate the apoptosis rate. Levels of nitric oxide (NO) and nitric oxide synthase (NOS) activity were measured by the Griess reaction and the conversion of 3H-arginine to 3H-citrulline, respectively. Endothelin-1 (ET-1) was evaluated by the enzyme-linked immunosorbent assay (ELISA). Cell proliferation was determined by the MTT viability assay. mRNA expression of endothelial nitric oxide synthase (eNOS) and ET-1 were measured by real-time PCR. Our data showed that EM1/EM2 inhibited cell apoptosis. The high glucose induced increase in expression of NO, NOS and ET-1 were significantly attenuated by pretreatment with EM1/EM2 in a dose dependent manner. In addition, EM1/EM2 suppressed the mRNA eNOS and mRNA ET-1 expression in HUVECs under high glucose conditions. Naloxone, the nonselective opioid receptor antagonist, did not influence the mRNA eNOS expression when it was administrated on its own; but it could significantly antagonize the effects induced by EM1/EM2. Furthermore, in all assay systems, EM1 was more potent than EM2. The results suggest that EM1/EM2 have a beneficial effect in protecting against the endothelial dysfunction by high glucose in vitro, and these effects were mediated by the opioid receptors in HUVECs.

  2. Increased glucose metabolism and alpha-glucosidase inhibition in Cordyceps militaris water extract-treated HepG2 cells.

    Science.gov (United States)

    Kim, Dae Jung; Kang, Yun Hwan; Kim, Kyoung Kon; Kim, Tae Woo; Park, Jae Bong; Choe, Myeon

    2017-06-01

    Recent living condition improvements, changes in dietary habits, and reductions in physical activity are contributing to an increase in metabolic syndrome symptoms including diabetes and obesity. Through such societal developments, humankind is continuously exposed to metabolic diseases such as diabetes, and the number of the victims is increasing. This study investigated Cordyceps militaris water extract (CMW)-induced glucose uptake in HepG2 cells and the effect of CMW treatment on glucose metabolism. Colorimetric assay kits were used to determine the glucokinase (GK) and pyruvate dehydrogenase (PDH) activities, glucose uptake, and glycogen content. Either RT-PCR or western blot analysis was performed for quantitation of glucose transporter 2 (GLUT2), hepatocyte nuclear factor 1 alpha (HNF-1α), phosphatidylinositol 3-kinase (PI3k), protein kinase B (Akt), phosphorylated AMP-activated protein kinase (pAMPK), phosphoenolpyruvate carboxykinase, GK, PDH, and glycogen synthase kinase 3 beta (GSK-3β) expression levels. The α-glucosidase inhibitory activities of acarbose and CMW were evaluated by absorbance measurement. CMW induced glucose uptake in HepG2 cells by increasing GLUT2 through HNF-1α expression stimulation. Glucose in the cells increased the CMW-induced phosphorylation of AMPK. In turn, glycolysis was stimulated, and glyconeogenesis was inhibited. Furthermore, by studying the mechanism of action of PI3k, Akt, and GSK-3β, and measuring glycogen content, the study confirmed that the glucose was stored in the liver as glycogen. Finally, CMW resulted in a higher level of α-glucosidase inhibitory activity than that from acarbose. CMW induced the uptake of glucose into HepG2 cells, as well, it induced metabolism of the absorbed glucose. It is concluded that CMW is a candidate or potential use in diabetes prevention and treatment.

  3. Inhibition of food intake in the rat following complete absorption of glucose delivered into the stomach, intestine or liver.

    Science.gov (United States)

    Booth, D A; Jarman, S P

    1976-07-01

    1. Solutions of glucose or other carbohydrates were administered during the dark or light period of the circadian cycle to rats which had been only briefly deprived of food. 2. food was restored to the animals at various times after administration of a glucose load by stomach tube. With delays between loading and access to food of up to 3 hr by night and 2 hr by day, subsequent food intake was less than intake after non-nutritive loads. 3. measurement of the glucose content of the gastrointestinal tract at various times after glucose loading showed that this depression of intake was still apparent even when the rat was offered food some time after complete absorption of the stomach load. 4. infusion of a glucose solution into the duodenum or the hepatic protal vein also inhibited subsequent food intake. 5. in all cases, the inhibition of food intake was expressed as a decrease in the size of the first meal after restoring access to food. 6. these results provide the first demonstration that the entry of normal amounts of carbohydrate into the body by the physiological route is followed by depression of food intake which lasts until after absorption is complete.

  4. Green tea decoction improves glucose tolerance and reduces weight gain of rats fed normal and high-fat diet.

    Science.gov (United States)

    Snoussi, Chahira; Ducroc, Robert; Hamdaoui, Mohamed Hédi; Dhaouadi, Karima; Abaidi, Houda; Cluzeaud, Francoise; Nazaret, Corinne; Le Gall, Maude; Bado, André

    2014-05-01

    Green tea containing polyphenols exerts antidiabetic and antiobesity effects, but the mechanisms involved are not fully understood. In this study, we first analyzed and compared polyphenol compounds [epigallocatechin gallate (EGCG), epigallocatechin (EGC)] in decoction of green tea leaves versus usual green tea extracts. Second, the effects of acute (30 min) or chronic (6 weeks) oral administration of green tea decoction (GTD) on intestinal glucose absorption were studied in vitro in Ussing chamber, ex vivo using isolated jejunal loops and in vivo through glucose tolerance tests. Finally, we explore in rat model fed normal or high-fat diet the effects of GTD on body weight, blood parameters and on the relative expression of glucose transporters SGLT-1, GLUT2 and GLUT4. GTD cooked for 15 min contained the highest amounts of phenolic compounds. In fasted rats, acute administration of GTD inhibited SGLT-1 activity, increased GLUT2 activity and improved glucose tolerance. Similarly to GTD, acute administration of synthetic phenolic compounds (2/3 EGCG+1/3 EGC) inhibited SGLT-1 activity. Chronic administration of GTD in rat fed high-fat diet reduced body weight gain, circulating triglycerides and cholesterol and improved glucose tolerance. GTD-treated rats for 6 weeks display significantly reduced SGLT-1 and increased GLUT2 mRNA levels in the jejunum mucosa. Moreover, adipose tissue GLUT4 mRNA levels were increased. These results indicate that GTD, a traditional beverage rich in EGCG and EGC reduces intestinal SGLT-1/GLUT2 ratio, a hallmark of regulation of glucose absorption in enterocyte, and enhances adipose GLUT4 providing new insights in its possible role in the control of glucose homeostasis. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. The Effect of Noscapine on Oxygen-Glucose Deprivation on Primary Murine Cortical Neurons in High Glucose Condition.

    Science.gov (United States)

    Vahabzadeh, Gelareh; Ebrahimi, Soltan-Ahmed; Rahbar-Roshandel, Nahid; Mahmoudian, Massoud

    2016-01-01

    In the present work we set out to investigate the neuroprotective effects of noscapine (0.5-2 µM) in presence of D-glucose on primary murine foetal cortical neurons after oxygen-glucose deprivation/24 h. recovery. Cell viability, nitric oxide production and intracellular calcium ((ca(2+))i) levels were evaluated by MTT assay, the modified Griess method and Fura-2 respectively. 25 and 100 mM D-glucose could, in a concentration dependent manner, improve cell viability and decrease NO production and (ca(2+))i level in neuronal cells after ischemic insult. Moreover, pre-incubation of cells with noscapine, noticeably enhanced protective effects of 25 and 100 mM D-glucose compared to similar conditions without noscapine pre-treatment. In fact, noscapine attenuated NO production in a dose-dependent fashion, after 30 minutes (min) OGD, during high-glucose (HG) condition in cortical neurons. Pretreatment with 2 μM noscapine and 25 or 100 mM D-glucose, was shown to decrease the rise in (ca(2+))i induced by Sodium azide/glucose deprivation (chemical OGD) model. These effects were more pronounced than that of 25 or 100 mM D-glucose alone. The present study demonstrated that the neuroprotective effects of HG before an ischemic insult were augmented by pre-treatment with noscapine. Our results also suggested that the neuroprotection offered by both HG and noscapine involve attenuation of NO production and (ca(2+))i levels stimulated by the experimental ischemia in cortical neurons.

  6. Involvement of AMPK in regulating the degradation of MAD2B under high glucose in neuronal cells.

    Science.gov (United States)

    Meng, Xianfang; Chu, Guangpin; Ye, Chen; Tang, Hui; Qiu, Ping; Hu, Yue; Li, Man; Zhang, Chun

    2016-12-13

    Although our recent study has demonstrated that mitotic spindle assembly checkpoint protein (MAD2B) mediates high glucose-induced neuronal apoptosis, the mechanisms for MAD2B degradation under hyperglycaemia have not yet been elucidated. In this study, we first found that the activation of adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) was decreased in neurons, accompanied with the increased expression of MAD2B. Mechanistically, we demonstrated that activation of AMPK with its activators such as AICAR and metformin decreased the expression of MAD2B, indicating a role of AMPK in regulating the expression of MAD2B. Moreover, activation of AMPK prevented neuronal cells from high glucose-induced injury as demonstrated by the reduced expression of cyclin B1 and percentage of apoptosis as detected by TUNEL. We further found that when total protein synthesis was suppressed by chlorhexidine, the degradation of MAD2B was slower in high glucose-treated neurons and was mainly dependent on the ubiquitin-proteasome system. Finally, it was indicated that high glucose inhibited the ubiquitination of MAD2B, which could be reversed by activation of AMPK. Collectively, this study demonstrates that AMPK acts as a key regulator of MAD2B expression, suggesting that activation of AMPK signalling might be crucial for the treatment of high glucose-induced neuronal injury.

  7. Isoflavone genistein protects high glucose-induced human aortic endothelial cell apoptosis through estrogen receptor-mediated pathway

    Institute of Scientific and Technical Information of China (English)

    Wenwen Zhong; Yang Liu; Guang Yang; Hui Tian

    2008-01-01

    Objective The aim of this study was to determine if isoflavone genistien has protective effects against high glucose-induced cell apoptosis in human aortic endlthelial cells,and investigate the possible mechanism for this protection.Methods Human aortic endothelial cells subjected to normal (5mmol/L) or high glucose (25mmol/L) were treated with genistein at 0,50,100nmol/L.Parallel experiments were performed with 100nM 17b-estradiol,and also in the presence and absence of the pure anti-estrogen ICI-182,780 (100nmol/L).The effects on cell apoptotic DNA fragmentation were determined using cell death ELISA,and the effects on cellular proliferation were determined using tritiated thymidine incorporation assay.Estrogen receptor expression was detected by Taqman quantitative PCR.Results Genistein at 100nmol/L significantly reduced high glucose-induced DNA fragmentation,and reversed cell DNA synthesis inhibition (P<0.001) after 24 hours' incubation.The effect of genistein was completely blocked by ICI-182,780administration.Estrogen receptor beta,but not alpha was found to be expressed in these cells.Conclusion Isoflavone genistein shows protection against high glucose-induced cell damage through estrogen receptor beta,reducing apoptotic DNA damage and protecting from the inhibition of cell proliferation.

  8. Effects of astragalosides from Radix Astragali on high glucose-induced proliferation and extracellular matrix accumulation in glomerular mesangial cells

    Science.gov (United States)

    CHEN, XIAO; WANG, DONG-DONG; WEI, TONG; HE, SU-MEI; ZHANG, GUAN-YING; WEI, QUN-LI

    2016-01-01

    Diabetic nephropathy (DN) exhibits a deteriorating course that may lead to end-stage renal failure. Astragalosides have been clinically tested for the treatment of DN, but the mechanism is unclear at present. In this study, the effects of astragalosides were investigated on high glucose-induced proliferation and expression of transforming growth factor-β1 (TGF-β1), connective tissue growth factor (CTGF), type IV collagen (colIV) and fibronectin (FN) in glomerular mesangial cells (MCs). Cell proliferation was determined by 5-bromo-2′-deoxyuridine assay, and the expression of TGF-β1, CTGF, colIV and FN mRNA and proteins in MCs was detected by reverse transcription-polymerase chain reaction and ELISA assay, respectively. The results showed that high glucose clearly induced the proliferation of MCs and increased the expression of TGF-β1, CTGF, colIV and FN. Treatment with 50, 100, 200 µg/ml astragalosides inhibited cell proliferation and the expression of TGF-β1, CTGF, colIV and FN induced by high glucose. Thus, it is concluded that astragalosides inhibit the increased cell proliferation and expression of major extracellular matrix proteins that are induced by high glucose, indicating their value for the prophylaxis and therapy of DN. PMID:27313676

  9. Inhibition of sweet chemosensory receptors alters insulin responses during glucose ingestion in healthy adults: a randomized crossover interventional study.

    Science.gov (United States)

    Karimian Azari, Elnaz; Smith, Kathleen R; Yi, Fanchao; Osborne, Timothy F; Bizzotto, Roberto; Mari, Andrea; Pratley, Richard E; Kyriazis, George A

    2017-04-01

    Background: Glucose is a natural ligand for sweet taste receptors (STRs) that are expressed on the tongue and in the gastrointestinal tract. Whether STRs directly contribute to the regulation of glucose homeostasis in response to glucose ingestion is unclear.Objective: We sought to determine the metabolic effects of the pharmacologic inhibition of STRs in response to an oral glucose load in healthy lean participants.Design: Ten healthy lean participants with a body mass index (in kg/m(2)) of 22.4 ± 0.8 were subjected to an oral-glucose-tolerance test (OGTT) on 4 separate days with the use of a randomized crossover design. Ten minutes before the 75-g OGTT, participants consumed a preload solution of either 300 parts per million (ppm) saccharin or water with or without the addition of 500 ppm lactisole, a human-specific inhibitor of STRs. When present, lactisole was included in both the preload and OGTT solutions. We assessed plasma responses of glucose, insulin, C-peptide, glucagon, glucagon-like peptides 1 and 2, gastric inhibitory peptide, acetaminophen, and 3-O-methylglucose. With the use of mathematical modeling, we estimated gastric emptying, glucose absorption, β-cell function, insulin sensitivity and clearance, and the portal insulin:glucagon ratio.Results: The addition of lactisole to the OGTT caused increases in the plasma responses of insulin (P = 0.012), C-peptide (P = 0.004), and the insulin secretory rate (P = 0.020) compared with the control OGTT. The addition of lactisole also caused a slight reduction in the insulin sensitivity index independent of prior saccharin consumption (P insulin responses during an oral glucose challenge in lean healthy participants. This trial was registered at clinicaltrials.gov as NCT02835859. © 2017 American Society for Nutrition.

  10. A free-choice high-fat high-sugar diet induces glucose intolerance and insulin unresponsiveness to a glucose load not explained by obesity

    NARCIS (Netherlands)

    S.E. la Fleur; M.C.M. Luijendijk; A.J. van Rozen; A. Kalsbeek; R.A.H. Adan

    2011-01-01

    Objectives: In diet-induced obesity, it is not clear whether impaired glucose metabolism is caused directly by the diet, or indirectly via obesity. This study examined the effects of different free-choice, high-caloric, obesity-inducing diets on glucose metabolism. In these free-choice diets, satura

  11. Rebaudioside A directly stimulates insulin secretion from pancreatic beta cells: a glucose-dependent action via inhibition of ATP-sensitive K-channels.

    Science.gov (United States)

    Abudula, R; Matchkov, V V; Jeppesen, P B; Nilsson, H; Aalkjaer, C; Hermansen, K

    2008-11-01

    Recently, we showed that rebaudioside A potently stimulates the insulin secretion from isolated mouse islets in a dose-, glucose- and Ca(2+)-dependent manner. Little is known about the mechanisms underlying the insulinotropic action of rebaudioside A. The aim of this study was to define the signalling system by which, rebaudioside A acts. Isolated mouse islets were used in the cAMP[(125)I] scintillation proximity assay to measure total cAMP level, and in a luminometric method to measure intracellular ATP and ADP concentrations. Conventional and permeabilized whole-cell configuration of the patch-clamp technique was used to verify the effect of rebaudioside A on ATP-sensitive K(+)-channels from dispersed single beta cells from isolated mouse islets. Insulin was measured by radioimmunoassay from insulinoma MIN6 cells. In the presence of 16.7 mM glucose, the addition of the maximally effective concentration of rebaudioside A (10(-9) M) increased the ATP/ADP ratio significantly, while it did not change the intracellular cAMP level. Rebaudioside A (10(-9) M) and stevioside (10(-6) M) reduced the ATP-sensitive potassium channel (K(ATP)) conductance in a glucose-dependent manner. Moreover, rebaudioside A stimulated the insulin secretion from MIN6 cells in a dose- and glucose-dependent manner. In conclusion, the insulinotropic effect of rebaudioside A is mediated via inhibition of ATP-sensitive K(+)-channels and requires the presence of high glucose. The inhibition of ATP-sensitive K(+)-channels is probably induced by changes in the ATP/ADP ratio. The results indicate that rebaudioside A may offer a distinct therapeutic advantage over sulphonylureas because of less risk of causing hypoglycaemia.

  12. Over-the-counter analgesics normalize blood glucose and body composition in mice fed a high fat diet.

    Science.gov (United States)

    Kendig, Eric L; Schneider, Scott N; Clegg, Deborah J; Genter, Mary Beth; Shertzer, Howard G

    2008-07-15

    Type 2 diabetes (noninsulin-dependent diabetes mellitus) develops from a pre-diabetic condition that is characterized by insulin resistance and glucose intolerance, and is exacerbated by obesity. In this study, we compared the ability of over-the-counter analgesic drugs (OTCAD) [acetaminophen (APAP); ibuprofen (IBU); naproxen (NAP); aspirin (ASA)], to protect against the development of a pre-diabetic state in mice fed a high fat diet. After 10 weeks on the high fat diet, mice had normal fasting blood glucose (FBG) levels, but exhibited impaired glucose tolerance. Treatment with 20 mg OTCADs/kg body weight improved glucose tolerance, with the order of efficacy, APAP=ASA>IBU, while NAP proved ineffective. Mice fed the high fat diet also exhibited increases in weight gain associated with an increase in body fat. OTCADs prevented in part this increase in body fat, in the order of efficacy, APAP=IBU>NAP=ASA. In isolated liver mitochondria, OTCADs inhibited succinate-dependent H2O2 production, while in white adipose tissue, APAP inhibited NADPH-oxidase mediated H2O2 production and lipid peroxidation. Thus, OTCADs diminish pro-oxidant processes that might otherwise exacerbate inflammation and a pre-diabetic state. We conclude that OTCADs, especially APAP and IBU, may be valuable tools to delay or prevent the development of type 2 diabetes from a pre-diabetic condition.

  13. Free fatty acids or high-concentration glucose enhances hepatitis A virus replication in association with a reduction in glucose-regulated protein 78 expression.

    Science.gov (United States)

    Nwe Win, Nan; Kanda, Tatsuo; Nakamura, Masato; Nakamoto, Shingo; Okamoto, Hiroaki; Yokosuka, Osamu; Shirasawa, Hiroshi

    2017-01-29

    Although the interaction between host and hepatitis A virus (HAV) factors could lead to severe hepatitis A, the exact mechanism of acute liver failure caused by HAV infection is not yet fully understood. The effects of metabolic diseases such as dyslipidemia or diabetes mellitus on HAV replication are still unknown. Here, we examined the effects of free fatty acids or high-concentration glucose on HAV replication and the effects on mitogen-activated protein kinase signaling pathway-related genes in human hepatocytes. We discovered a novel effect of free fatty acids or high-concentration glucose on HAV replication in association with a reduction in the expression of glucose-regulated protein 78 (GRP78). We also observed that thapsigargin induced GRP78 expression and inhibited HAV replication. These findings may provide a new interpretation of the relationship between metabolic diseases and severity of hepatitis A and suggest a new understanding of the mechanism of severe HAV infection. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. A novel PKB/Akt inhibitor, MK-2206, effectively inhibits insulin-stimulated glucose metabolism and protein synthesis in isolated rat skeletal muscle.

    Science.gov (United States)

    Lai, Yu-Chiang; Liu, Yang; Jacobs, Roxane; Rider, Mark H

    2012-10-01

    PKB (protein kinase B), also known as Akt, is a key component of insulin signalling. Defects in PKB activation lead to insulin resistance and metabolic disorders, whereas PKB overactivation has been linked to tumour growth. Small-molecule PKB inhibitors have thus been developed for cancer treatment, but also represent useful tools to probe the roles of PKB in insulin action. In the present study, we examined the acute effects of two allosteric PKB inhibitors, MK-2206 and Akti 1/2 (Akti) on PKB signalling in incubated rat soleus muscles. We also assessed the effects of the compounds on insulin-stimulated glucose uptake, glycogen and protein synthesis. MK-2206 dose-dependently inhibited insulin-stimulated PKB phosphorylation, PKBβ activity and phosphorylation of PKB downstream targets (including glycogen synthase kinase-3α/β, proline-rich Akt substrate of 40 kDa and Akt substrate of 160 kDa). Insulin-stimulated glucose uptake, glycogen synthesis and glycogen synthase activity were also decreased by MK-2206 in a dose-dependent manner. Incubation with high doses of MK-2206 (10 μM) inhibited insulin-induced p70 ribosomal protein S6 kinase and 4E-BP1 (eukaryotic initiation factor 4E-binding protein-1) phosphorylation associated with increased eEF2 (eukaryotic elongation factor 2) phosphorylation. In contrast, Akti only modestly inhibited insulin-induced PKB and mTOR (mammalian target of rapamycin) signalling, with little or no effect on glucose uptake and protein synthesis. MK-2206, rather than Akti, would thus be the tool of choice for studying the role of PKB in insulin action in skeletal muscle. The results point to a key role for PKB in mediating insulin-stimulated glucose uptake, glycogen synthesis and protein synthesis in skeletal muscle.

  15. Catalytic site inhibition of insulin-degrading enzyme by a small molecule induces glucose intolerance in mice.

    Science.gov (United States)

    Deprez-Poulain, Rebecca; Hennuyer, Nathalie; Bosc, Damien; Liang, Wenguang G; Enée, Emmanuelle; Marechal, Xavier; Charton, Julie; Totobenazara, Jane; Berte, Gonzague; Jahklal, Jouda; Verdelet, Tristan; Dumont, Julie; Dassonneville, Sandrine; Woitrain, Eloise; Gauriot, Marion; Paquet, Charlotte; Duplan, Isabelle; Hermant, Paul; Cantrelle, François-Xavier; Sevin, Emmanuel; Culot, Maxime; Landry, Valerie; Herledan, Adrien; Piveteau, Catherine; Lippens, Guy; Leroux, Florence; Tang, Wei-Jen; van Endert, Peter; Staels, Bart; Deprez, Benoit

    2015-09-23

    Insulin-degrading enzyme (IDE) is a protease that cleaves insulin and other bioactive peptides such as amyloid-β. Knockout and genetic studies have linked IDE to Alzheimer's disease and type-2 diabetes. As the major insulin-degrading protease, IDE is a candidate drug target in diabetes. Here we have used kinetic target-guided synthesis to design the first catalytic site inhibitor of IDE suitable for in vivo studies (BDM44768). Crystallographic and small angle X-ray scattering analyses show that it locks IDE in a closed conformation. Among a panel of metalloproteases, BDM44768 selectively inhibits IDE. Acute treatment of mice with BDM44768 increases insulin signalling and surprisingly impairs glucose tolerance in an IDE-dependent manner. These results confirm that IDE is involved in pathways that modulate short-term glucose homeostasis, but casts doubt on the general usefulness of the inhibition of IDE catalytic activity to treat diabetes.

  16. Reduction of glucose uptake through inhibition of hexose transporters and enhancement of their endocytosis by methylglyoxal in Saccharomyces cerevisiae.

    Science.gov (United States)

    Yoshida, Aya; Wei, Dandan; Nomura, Wataru; Izawa, Shingo; Inoue, Yoshiharu

    2012-01-02

    Diabetes mellitus is characterized by an impairment of glucose uptake even though blood glucose levels are increased. Methylglyoxal is derived from glycolysis and has been implicated in the development of diabetes mellitus, because methylglyoxal levels in blood and tissues are higher in diabetic patients than in healthy individuals. However, it remains to be elucidated whether such factors are a cause, or consequence, of diabetes. Here, we show that methylglyoxal inhibits the activity of mammalian glucose transporters using recombinant Saccharomyces cerevisiae cells genetically lacking all hexose transporters but carrying cDNA for human GLUT1 or rat GLUT4. We found that methylglyoxal inhibits yeast hexose transporters also. Glucose uptake was reduced in a stepwise manner following treatment with methylglyoxal, i.e. a rapid reduction within 5 min, followed by a slow and gradual reduction. The rapid reduction was due to the inhibitory effect of methylglyoxal on hexose transporters, whereas the slow and gradual reduction seemed due to endocytosis, which leads to a decrease in the amount of hexose transporters on the plasma membrane. We found that Rsp5, a HECT-type ubiquitin ligase, is responsible for the ubiquitination of hexose transporters. Intriguingly, Plc1 (phospholipase C) negatively regulated the endocytosis of hexose transporters in an Rsp5-dependent manner, although the methylglyoxal-induced endocytosis of hexose transporters occurred irrespective of Plc1. Meanwhile, the internalization of hexose transporters following treatment with methylglyoxal was delayed in a mutant defective in protein kinase C.

  17. Reduced phosphorylation of AS160 contributes to glucocorticoid-mediated inhibition of glucose uptake in human and murine adipocytes.

    Science.gov (United States)

    Ngo, Sherry; Barry, Janelle B; Nisbet, Janelle C; Prins, Johannes B; Whitehead, Jonathan P

    2009-04-10

    Excess glucocorticoids induce insulin resistance and reduce glucose uptake although the underlying mechanisms are unclear. Here we demonstrate that Dex (1 microM for 24h) inhibits basal and insulin (1 nM) stimulated glucose uptake in human and murine adipocytes by 50% with a concomitant reduction in the levels of GLUT1/4 at the plasma membrane but no change in total GLUT1/4 levels. Expression and phosphorylation of proximal insulin signalling molecules (IRS1, PI3K, AKT) was unaffected by Dex as was phosphorylation of mTOR and FOXO1. In contrast, phosphorylation of AKT substrate 160kDa (AS160) at T642, which is essential for 14-3-3 recruitment and GLUT4 translocation, was reduced by 50% in basal and insulin-stimulated cells and this was mirrored by decreased 14-3-3 association. Co-treatment with the glucocorticoid receptor antagonist RU486 (10 microM) abrogated the Dex effect on AS160-T642 phosphorylation and restored glucose uptake by 80%. These data suggest Dex inhibits glucose uptake in adipocytes, at least in part, by reducing AS160 phosphorylation and interaction with 14-3-3.

  18. Synergistic effect of high glucose and ANG II on proliferation of mouse embryonic stem cells: involvement of PKC and MAPKs as well as AT1 receptor.

    Science.gov (United States)

    Kim, Yun Hee; Han, Ho Jae

    2008-05-01

    This study examined the synergistic effect of high glucose levels and ANG II on proliferation and its related signal pathways using mouse embryonic stem (ES) cells. The combined use of a high glucose concentration (25 mM) and ANG II increased the level of [3H]thymidine/BrdU incorporation, and the number of cells compared with either treatment alone. Each treatment with high glucose or ANG II increased the cell population in the S phase compared with control, and the combined treatment of a high glucose concentration and ANG II significantly increased the number of cells in the S phase according to FACS analysis. Moreover, the high glucose-induced increase in [3H]thymidine incorporation was blocked by inhibiting the ANG II type 1 (AT1) receptor. The combined high glucose and ANG II significantly increased the STAT3 phosphorylation compared with high glucose or ANG II alone. ANG II stimulated the influx of Ca2+ in 25 mM glucose compared with 5 mM glucose. High glucose levels increase the level of PKC alpha, epsilon, and zeta translocation from the cytosol to the membrane fraction. In an examination of other signal pathways, the combined treatment significantly increased the level of p44/42, p38 MAPKs phosphorylation compared with either treatment alone. Indeed, the combined treatment increased the mRNA expression level of the protooncogenes and cell cycle regulatory proteins. In conclusion, the combined treatment of a high glucose concentration and ANG II had a synergistic effect in stimulating mouse ES cell proliferation through the Ca2+/PKC, MAPKs, and the AT1 receptor.

  19. Fisetin improves glucose homeostasis through the inhibition of gluconeogenic enzymes in hepatic tissues of streptozotocin induced diabetic rats.

    Science.gov (United States)

    Prasath, Gopalan Sriram; Pillai, Subramanian Iyyam; Subramanian, Sorimuthu Pillai

    2014-10-05

    Liver plays a vital role in blood glucose homeostasis. Recent studies have provided considerable evidence that hepatic glucose production (HGP) plays an important role in the development of fasting hyperglycemia in diabetes. From this perspective, diminution of HGP has certainly been considered for the treatment of diabetes. In the present study, we have analyzed the modulatory effects of fisetin, a flavonoid of strawberries, on the expression of key enzymes of carbohydrate metabolism in STZ induced experimental diabetic rats. The physiological criterions such as food and fluid intake were regularly monitored. The levels of blood glucose, plasma insulin, hemoglobin and glycosylated hemoglobin were analyzed. The mRNA and protein expression levels of gluconeogenic genes such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase) were determined by immunoblot as well as PCR analysis. Diabetic group of rats showed significant increase in food and water intake when compared with control group of rats. Upon oral administration of fisetin as well as gliclazide to diabetic group of rats, the levels were found to be decreased. Oral administration of fisetin (10 mg/kg body weight) to diabetic rats for 30 days established a significant decline in blood glucose and glycosylated hemoglobin levels and a significant increase in plasma insulin level. The mRNA and protein expression levels of gluconeogenic genes, such as phosphoenolpyruvate carboxykinase (PEPCK) and glucose-6-phosphatase (G6Pase), were decreased in liver tissues upon treatment with fisetin. The results of the present study suggest that fisetin improves glucose homeostasis by direct inhibition of gluconeogenesis in liver. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Inhibition of the gut enzyme intestinal alkaline phosphatase may explain how aspartame promotes glucose intolerance and obesity in mice.

    Science.gov (United States)

    Gul, Sarah S; Hamilton, A Rebecca L; Munoz, Alexander R; Phupitakphol, Tanit; Liu, Wei; Hyoju, Sanjiv K; Economopoulos, Konstantinos P; Morrison, Sara; Hu, Dong; Zhang, Weifeng; Gharedaghi, Mohammad Hadi; Huo, Haizhong; Hamarneh, Sulaiman R; Hodin, Richard A

    2017-01-01

    Diet soda consumption has not been associated with tangible weight loss. Aspartame (ASP) commonly substitutes sugar and one of its breakdown products is phenylalanine (PHE), a known inhibitor of intestinal alkaline phosphatase (IAP), a gut enzyme shown to prevent metabolic syndrome in mice. We hypothesized that ASP consumption might contribute to the development of metabolic syndrome based on PHE's inhibition of endogenous IAP. The design of the study was such that for the in vitro model, IAP was added to diet and regular soda, and IAP activity was measured. For the acute model, a closed bowel loop was created in mice. ASP or water was instilled into it and IAP activity was measured. For the chronic model, mice were fed chow or high-fat diet (HFD) with/without ASP in the drinking water for 18 weeks. The results were that for the in vitro study, IAP activity was lower (p < 0.05) in solutions containing ASP compared with controls. For the acute model, endogenous IAP activity was reduced by 50% in the ASP group compared with controls (0.2 ± 0.03 vs 0.4 ± 0.24) (p = 0.02). For the chronic model, mice in the HFD + ASP group gained more weight compared with the HFD + water group (48.1 ± 1.6 vs 42.4 ± 3.1, p = 0.0001). Significant difference in glucose intolerance between the HFD ± ASP groups (53 913 ± 4000.58 (mg·min)/dL vs 42 003.75 ± 5331.61 (mg·min)/dL, respectively, p = 0.02). Fasting glucose and serum tumor necrosis factor-alpha levels were significantly higher in the HFD + ASP group (1.23- and 0.87-fold increases, respectively, p = 0.006 and p = 0.01). In conclusion, endogenous IAP's protective effects in regard to the metabolic syndrome may be inhibited by PHE, a metabolite of ASP, perhaps explaining the lack of expected weight loss and metabolic improvements associated with diet drinks.

  1. Glucose-induced inhibition of seed germination in Lotus japonicus is alleviated by nitric oxide and spermine.

    Science.gov (United States)

    Zhao, Min-Gui; Liu, Ruo-Jing; Chen, Lei; Tian, Qiu-Ying; Zhang, Wen-Hao

    2009-01-30

    Seed germination is sensitive to glucose (Glc), nitric oxide (NO) and polyamine (PA). To elucidate whether cross-talk among Glc, NO and PAs occurs in mediation of seed germination, effects of Glc, NO and spermine on seed germination of Lotus japonicus were studied. Glc retarded seed germination in a concentration-dependent manner. NO donor sodium nitroprusside (SNP) alleviated Glc-induced inhibition of seed germination, whereas the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide (cPTIO) diminished the SNP-dependent alleviation of seed germination. These observations indicate that Glc may inhibit seed germination by interacting with NO signaling pathways. Exogenous spermine enhanced and the inhibitor of the spermine synthase, methylglyoxal-bis-guanyl hydrazone (MGBG), inhibited seed germination, respectively. Like SNP, spermine alleviated the Glc-induced inhibition of seed germination, whereas MGBG exaggerated the Glc-induced inhibition of seed germination. These results suggest that Glc may inhibit the spermine synthesis, leading to reductions in seed germination. NO scavenger and spermine synthase inhibitor diminished the SNP-induced alleviation of Glc-induced inhibition of seed germination. These findings reveal that both NO and spermine participate in the Glc-induced inhibition of seed germination in L. japonicus.

  2. Personalized metabolomics for predicting glucose tolerance changes in sedentary women after high-intensity interval training

    National Research Council Canada - National Science Library

    Kuehnbaum, Naomi L; Gillen, Jenna B; Gibala, Martin J; Britz-McKibbin, Philip

    2014-01-01

    High-intensity interval training (HIIT) offers a practical approach for enhancing cardiorespiratory fitness, however its role in improving glucose regulation among sedentary yet normoglycemic women remains unclear...

  3. Integration of a highly ordered gold nanowires array with glucose oxidase for ultra-sensitive glucose detection

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Jiewu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China); Adeloju, Samuel B., E-mail: sam.adeloju@monash.edu [NanoScience and Sensor Technology Research Group, School of Applied Sciences and Engineering, Monash University, Gippsland Campus, Churchill 3842, VIC Australia (Australia); Wu, Yucheng, E-mail: ycwu@hfut.edu.cn [Laboratory of Functional Nanomaterials and Devices, School of Materials Science and Engineering, Hefei University of Technology, Hefei 230009, Anhui (China)

    2014-01-27

    Graphical abstract: -- Highlights: •Successfully synthesised highly-ordered gold nanowires array with an AAO template. •Fabricated an ultra-sensitive glucose nanobiosensor with the gold nanowires array. •Achieved sensitivity as high as 379.0 μA cm{sup −2} mM{sup −1} and detection limit as low as 50 nM. •Achieved excellent anti-interference with aid of Nafion membrane towards UA and AA. •Enabled successful detection and quantification of glucose in human blood serum. -- Abstract: A highly sensitive amperometric nanobiosensor has been developed by integration of glucose oxidase (GO{sub x}) with a gold nanowires array (AuNWA) by cross-linking with a mixture of glutaraldehyde (GLA) and bovine serum albumin (BSA). An initial investigation of the morphology of the synthesized AuNWA by field emission scanning electron microscopy (FESEM) and field emission transmission electron microscopy (FETEM) revealed that the nanowires array was highly ordered with rough surface, and the electrochemical features of the AuNWA with/without modification were also investigated. The integrated AuNWA–BSA–GLA–GO{sub x} nanobiosensor with Nafion membrane gave a very high sensitivity of 298.2 μA cm{sup −2} mM{sup −1} for amperometric detection of glucose, while also achieving a low detection limit of 0.1 μM, and a wide linear range of 5–6000 μM. Furthermore, the nanobiosensor exhibited excellent anti-interference ability towards uric acid (UA) and ascorbic acid (AA) with the aid of Nafion membrane, and the results obtained for the analysis of human blood serum indicated that the device is capable of glucose detection in real samples.

  4. Effect of polysaccharide of dendrobium candidum on proliferation and apoptosis of human corneal epithelial cells in high glucose.

    Science.gov (United States)

    Li, Qiangxiang; Chen, Jing; Li, Yajia; Chen, Ting; Zou, Jing; Wang, Hua

    2017-08-01

    The aim of the study was to observe the effect of polysaccharide of dendrobium candidum (PDC) and high glucose on proliferation, apoptosis of human corneal epithelial cells (HCEC). The MTT method was used to screen and take the optimal high-glucose concentration, treatment time, and PDC concentration using HCEC and divide it into 4 groups: control group (C), high glucose group (HG), PDC group, and HG + PDC group. We observed and compared the effect of the 4 groups on HCEC proliferation by MTT, apoptosis by Annexin V-FITC/PI double fluorescent staining and flow cytometry (FCM), and expression of bax mRNA and bcl-2 mRNA by RT-qPCR. Compared with the control group, proliferative activity of HCEC cells was reduced; the cells apoptosis ratio was increased; the expression of bax mRNA was increased, and the expression of bcl-2 mRNA was reduced in the HG group. Proliferative activity of HCEC cells in the PDC group was increased, and the expression of bcl-2 mRNA was increased but that of bax mRNA was decreased. Proliferative activity of HCEC cells in the HG + PDC group was increased, but it could not restore to the normal level; the expression of bax mRNA was significantly decreased but the expression of bcl-2 mRNA was significantly increased. Our results demonstrate that high glucose can inhibit proliferative activity and induce apoptosis of HCEC. PDC can improve the proliferative activity of HCEC cells under the high glucose environment and reduce the apoptosis of cells by regulating the expression of bax and bcl-2. PDC play a very important role on protecting and repairing of corneal epithelial cells damage in high glucose.

  5. Myeloperoxidase amplified high glucose-induced endothelial dysfunction in vasculature: Role of NADPH oxidase and hypochlorous acid.

    Science.gov (United States)

    Tian, Rong; Ding, Yun; Peng, Yi-Yuan; Lu, Naihao

    2017-03-11

    Nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-derived reactive oxygen species (ROS) such as superoxide and hydrogen peroxide (H2O2), have emerged as important molecules in the pathogenesis of diabetic endothelial dysfunction. Additionally, neutrophils-derived myeloperoxidase (MPO) and MPO-catalyzed hypochlorous acid (HOCl) play important roles in the vascular injury. However, it is unknown whether MPO can use vascular-derived ROS to induce diabetic endothelial dysfunction. In the present study, we demonstrated that NADPH oxidase was the main source of ROS formation in high glucose-cultured human umbilical vein endothelial cells (HUVECs), and played a critical role in high glucose-induced endothelial dysfunction such as cell apoptosis, loss of cell viability and reduction of nitric oxide (NO). However, the addition of MPO could amplify the high glucose-induced endothelial dysfunction which was inhibited by the presence of apocynin (NADPH oxidase inhibitor), catalase (H2O2 scavenger), or methionine (HOCl scavenger), demonstrating the contribution of NADPH oxidase-H2O2-MPO-HOCl pathway in the MPO/high glucose-induced vascular injury. In high glucose-incubated rat aortas, MPO also exacerbated the NADPH oxidase-induced impairment of endothelium-dependent relaxation. Consistent with these in vitro data, in diabetic rat aortas, both MPO expresion and NADPH oxidase activity were increased while the endothelial function was simultaneously impaired. The results suggested that vascular-bound MPO could amplify high glucose-induced vascular injury in diabetes. MPO-NADPH oxidase-HOCl may represent an important pathogenic pathway in diabetic vascular diseases.

  6. Breviscapine ameliorates hypertrophy of cardiomyocytes induced by high glucose in diabetic rats via the PKC signaling pathway

    Institute of Scientific and Technical Information of China (English)

    Min WANG; Wen-bin ZHANG; Jun-hui ZHU; Guo-sheng FU; Bin-quan ZHOU

    2009-01-01

    Aim: To investigate the influence of breviscapine on high glucose-induced hypertrophy of cardiomyocytes and the relevant mechanism in vitro and in vivo.Methods: Cultured neonatal cardiomyocytes were divided into ⅰ) control; ⅱ) high glucose concentrations; ⅲ) high glucose+PKC inhibi-tor Ro-31-8220; ⅳ) high glucose+breviscapine; or ⅴ) high glucose+NF-κB inhibitor BAY11-7082. Cellular contraction frequency and volumes were measured; the expression of protein kinase C (PKC), NF-κB, TNF-α, and c-los were assessed by Western blot or reverse transcription-polymerase chain reaction (RT-PCR). Diabetic rats were induced by a single intraperitoneal injection of streptozotocin,and randomly divided into ⅰ) control rats; ⅱ) diabetic rats; or ⅲ) diabetic rats administered with breviscapine (10 or 25 mg·kg-1·d-1). After treatment with breviscapine for six weeks, the echocardiographic parameters were measured. All rats were then sacrificed and heart tissue was obtained for microscopy. The expression patterns of PKC, NF-κB, TNF-α, and c-los were measured by Western blot or RT-PCR.Results: Cardiomyocytes cultured in a high concentration of glucose showed an increased pulsatile frequency and cellular volume, as well as a higher expression of PKC, NF-κB, TNF-α, and c-fos compared with the control group. Breviscapine could partly prevent these changes. Diabetic rats showed relative cardiac hypertrophy and a higher expression of PKC, NF-κB, TNF-α, and c-los; treatment with breviscapine could ameliorate these changes in diabetic cardiomyopathy.Conclusion: Breviscapine prevented cardiac hypertrophy in diabetic rats by inhibiting the expression of PKC, which may have a protec-tive effect in the pathogenesis of diabetic cardiomyopathy via the PKC/NF-κB/C-fos signal transduction pathway.

  7. L-cysteine reversibly inhibits glucose-induced biphasic insulin secretion and ATP production by inactivating PKM2.

    Science.gov (United States)

    Nakatsu, Daiki; Horiuchi, Yuta; Kano, Fumi; Noguchi, Yoshiyuki; Sugawara, Taichi; Takamoto, Iseki; Kubota, Naoto; Kadowaki, Takashi; Murata, Masayuki

    2015-03-10

    Increase in the concentration of plasma L-cysteine is closely associated with defective insulin secretion from pancreatic β-cells, which results in type 2 diabetes (T2D). In this study, we investigated the effects of prolonged L-cysteine treatment on glucose-stimulated insulin secretion (GSIS) from mouse insulinoma 6 (MIN6) cells and from mouse pancreatic islets, and found that the treatment reversibly inhibited glucose-induced ATP production and resulting GSIS without affecting proinsulin and insulin synthesis. Comprehensive metabolic analyses using capillary electrophoresis time-of-flight mass spectrometry showed that prolonged L-cysteine treatment decreased the levels of pyruvate and its downstream metabolites. In addition, methyl pyruvate, a membrane-permeable form of pyruvate, rescued L-cysteine-induced inhibition of GSIS. Based on these results, we found that both in vitro and in MIN6 cells, L-cysteine specifically inhibited the activity of pyruvate kinase muscle isoform 2 (PKM2), an isoform of pyruvate kinases that catalyze the conversion of phosphoenolpyruvate to pyruvate. L-cysteine also induced PKM2 subunit dissociation (tetramers to dimers/monomers) in cells, which resulted in impaired glucose-induced ATP production for GSIS. DASA-10 (NCGC00181061, a substituted N,N'-diarylsulfonamide), a specific activator for PKM2, restored the tetramer formation and the activity of PKM2, glucose-induced ATP production, and biphasic insulin secretion in L-cysteine-treated cells. Collectively, our results demonstrate that impaired insulin secretion due to exposure to L-cysteine resulted from its direct binding and inactivation of PKM2 and suggest that PKM2 is a potential therapeutic target for T2D.

  8. Insulin sensitivity and inhibition by forskolin, dipyridamole and pentobarbital of glucose transport in three L6 muscle cell lines

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    L6 skeletal muscle myoblasts stably overexpressing glucose transporter GLUT1 or GLUT4 with exofacial myc-epitope tags were characterized for their response to insulin. In clonally selected cultures, 2-deoxyglucose uptake into L6-GLUT1myc myoblasts and myotubes was linear within the time of study. In L6-GLUT1myc and L6-GLUT4myc myoblasts, 100 nmol/L insulin treatment increased the GLUT1 content of the plasma membrane by 1.58±0.01 fold and the GLUT4 content 1.96±0.11 fold, as well as the 2-deoxyglucose uptake 1.53±0.09 and 1.86±0.17 fold respectively, all by a wortmannin-inhibitable manner. The phosphorylation of Akt in these two cell lines was increased by insulin. L6-GLUT1myc myoblasts showed a dose-dependent stimulation of glucose uptake by insulin, with unaltered sensitivity and maximal responsiveness compared with wild type cells. By contrast, the improved insulin responsiveness and sensitivity of glucose uptake were observed in L6-GLUT4myc myoblasts. Earlier studies indicated that forskolin might affect insulin-stimulated GLUT4 translocation. A 65% decrease of insulin-stimulated 2-deoxyglucose uptake in GLUT4myc cells was not due to an effect on GLUT4 mobilization to the plasma membrane, but instead on direct inhibition of GLUT4. Forskolin and dipyridamole are more potent inhibitors of GLUT4 than GLUT1. Alternatively, pentobarbital inhibits GLUT1 more than GLUT4. The use of these inhibitors confirmed that the overexpressed GLUT1 or GLUT4 are the major functional glucose transporters in unstimulated and insulin-stimulated L6 myoblasts. Therefore, L6-GLUT1myc and L6-GLUT4myc cells provide a platform to screen compounds that may have differential effects on GLUT isoform activity or may influence GLUT isoform mobilization to the cell surface of muscle cells.

  9. Frequency of diabetes, impaired fasting glucose, and glucose intolerance in high-risk groups identified by a FINDRISC survey in Puebla City, Mexico.

    Science.gov (United States)

    García-Alcalá, Hector; Genestier-Tamborero, Christelle Nathalie; Hirales-Tamez, Omara; Salinas-Palma, Jorge; Soto-Vega, Elena

    2012-01-01

    As a first step in the prevention of diabetes, the International Diabetes Federation recommends identification of persons at risk using the Finnish type 2 Diabetes Risk Assessment (FINDRISC) survey. The frequency of diabetes mellitus, impaired fasting glucose, and glucose intolerance in high-risk groups identified by FINDRISC is unknown in our country. The aim of this study was to determine the frequency of diabetes mellitus, impaired fasting glucose, and glucose intolerance in higher-risk groups using a FINDRISC survey in an urban population. We used a television program to invite interested adults to fill out a survey at a television station. An oral glucose tolerance test was performed in all persons with a FINDRISC score ≥ 15 points (high-risk and very high-risk groups). Patients were classified as normal (fasting glucose < 100 mg/dL and 2-hour glucose < 140 mg/dL), or having impaired fasting glucose (fasting glucose 100-125 mg/dL and 2-hour glucose < 140 mg/dL), glucose intolerance (fasting glucose < 126 mg/dL and 2-hour glucose 140-199 mg/dL), and diabetes mellitus (fasting glucose ≥ 126 mg/dL or 2-hour glucose ≥ 200 mg/dL). We describe the frequency of each diagnostic category in this selected population according to gender and age. A total of 186 patients had a score ≥ 15. The frequencies of diabetes mellitus, impaired fasting glucose, glucose intolerance, and normal glucose levels were 28.6%, 25.9%, 29.2%, and 16.2%, respectively. We found a higher frequency of diabetes mellitus and impaired fasting glucose in men than in women (33% versus 27% and 40% versus 21%, respectively) and more glucose intolerance in women than in men (34% versus 16%, P < 0.05). Patients with diabetes mellitus (52.55 ± 9.2 years) were older than those with impaired fasting glucose (46.19 ± 8.89 years), glucose intolerance (46.15 ± 10.9 years), and normal levels (41.9 ± 10.45 years, P < 0.05). We found a higher frequency of diabetes mellitus in those aged over 50 years

  10. High glucose potentiates L-FABP mediated fibrate induction of PPARα in mouse hepatocytes.

    Science.gov (United States)

    Petrescu, Anca D; McIntosh, Avery L; Storey, Stephen M; Huang, Huan; Martin, Gregory G; Landrock, Danilo; Kier, Ann B; Schroeder, Friedhelm

    2013-08-01

    Although liver fatty acid binding protein (L-FABP) binds fibrates and PPARα in vitro and enhances fibrate induction of PPARα in transformed cells, the functional significance of these findings is unclear, especially in normal hepatocytes. Studies with cultured primary mouse hepatocytes show that: 1) At physiological (6mM) glucose, fibrates (bezafibrate, fenofibrate) only weakly activated PPARα transcription of genes in LCFA β-oxidation; 2) High (11-20mM) glucose, but not maltose (osmotic control), significantly potentiated fibrate-induction of mRNA of these and other PPARα target genes to increase LCFA β-oxidation. These effects were associated with fibrate-mediated redistribution of L-FABP into nuclei-an effect prolonged by high glucose-but not with increased de novo fatty acid synthesis from glucose; 3) Potentiation of bezafibrate action by high glucose required an intact L-FABP/PPARα signaling pathway as shown with L-FABP null, PPARα null, PPARα inhibitor-treated WT, or PPARα-specific fenofibrate-treated WT hepatocytes. High glucose alone in the absence of fibrate was ineffective. Thus, high glucose potentiation of PPARα occurred through FABP/PPARα rather than indirectly through other PPARs or glucose induced signaling pathways. These data indicated L-FABP's importance in fibrate-induction of hepatic PPARα LCFA β-oxidative genes, especially in the context of high glucose levels.

  11. Corrosion inhibition of mild steel in 1 M HCl solution by henna extract: A comparative study of the inhibition by henna and its constituents (Lawsone, Gallic acid, {alpha}-D-Glucose and Tannic acid)

    Energy Technology Data Exchange (ETDEWEB)

    Ostovari, A. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of)], E-mail: A.Ostovari@gmail.com; Hoseinieh, S.M.; Peikari, M. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of); Shadizadeh, S.R. [Petroleum Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of); Hashemi, S.J. [Technical Inspection Engineering Department, Petroleum University of Technology, Abadan (Iran, Islamic Republic of)

    2009-09-15

    The inhibitive action of henna extract (Lawsonia inermis) and its main constituents (lawsone, gallic acid, {alpha}-D-Glucose and tannic acid) on corrosion of mild steel in 1 M HCl solution was investigated through electrochemical techniques and surface analysis (SEM/EDS). Polarization measurements indicate that all the examined compounds act as a mixed inhibitor and inhibition efficiency increases with inhibitor concentration. Maximum inhibition efficiency (92.06%) is obtained at 1.2 g/l henna extract. Inhibition efficiency increases in the order: lawsone > henna extract > gallic acid > {alpha}-D-Glucose > tannic acid. Also, inhibition mechanism and thermodynamic parameters are discussed.

  12. Adrenergic receptor stimulation attenuates insulin-stimulated glucose uptake in 3T3-L1 adipocytes by inhibiting GLUT4 translocation

    NARCIS (Netherlands)

    Mulder, A.; Tack, C.J.J.; Olthaar, A.J.; Smits, P.; Sweep, C.G.J.; Bosch, R.R.

    2005-01-01

    Activation of the sympathetic nervous system inhibits insulin-stimulated glucose uptake. However, the underlying mechanisms are incompletely understood. Therefore, we studied the effects of catecholamines on insulin-stimulated glucose uptake and insulin-stimulated translocation of GLUT4 to the plasm

  13. The ATP Receptors P2X7 and P2X4 Modulate High Glucose and Palmitate-Induced Inflammatory Responses in Endothelial Cells.

    Directory of Open Access Journals (Sweden)

    Ramasri Sathanoori

    Full Text Available Endothelial cells lining the blood vessels are principal players in vascular inflammatory responses. Dysregulation of endothelial cell function caused by hyperglycemia, dyslipidemia, and hyperinsulinemia often result in impaired vasoregulation, oxidative stress, inflammation, and altered barrier function. Various stressors including high glucose stimulate the release of nucleotides thus initiating signaling via purinergic receptors. However, purinergic modulation of inflammatory responses in endothelial cells caused by high glucose and palmitate remains unclear. In the present study, we investigated whether the effect of high glucose and palmitate is mediated by P2X7 and P2X4 and if they play a role in endothelial cell dysfunction. Transcript and protein levels of inflammatory genes as well as reactive oxygen species production, endothelial-leukocyte adhesion, and cell permeability were investigated in human umbilical vein endothelial cells exposed to high glucose and palmitate. We report high glucose and palmitate to increase levels of extracellular ATP, expression of P2X7 and P2X4, and inflammatory markers. Both P2X7 and P2X4 antagonists inhibited high glucose and palmitate-induced interleukin-6 levels with the former having a significant effect on interleukin-8 and cyclooxygenase-2. The effect of the antagonists was confirmed with siRNA knockdown of the receptors. In addition, P2X7 mediated both high glucose and palmitate-induced increase in reactive oxygen species levels and decrease in endothelial nitric oxide synthase. Blocking P2X7 inhibited high glucose and palmitate-induced expression of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 as well as leukocyte-endothelial cell adhesion. Interestingly, high glucose and palmitate enhanced endothelial cell permeability that was dependent on both P2X7 and P2X4. Furthermore, antagonizing the P2X7 inhibited high glucose and palmitate-mediated activation of p38-mitogen

  14. The Glucose Sensor-Like Protein Hxs1 Is a High-Affinity Glucose Transporter and Required for Virulence in Cryptococcus neoformans

    Science.gov (United States)

    Baker, Gregory M.; Fahmy, Hany; Jiang, Linghuo; Xue, Chaoyang

    2013-01-01

    Cryptococcus is a major fungal pathogen that frequently causes systemic infection in patients with compromised immunity. Glucose, an important signal molecule and the preferred carbon source for Cryptococcus, plays a critical role in fungal development and virulence. Cryptococcus contains more than 50 genes sharing high sequence homology with hexose transporters in Saccharomyces cerevisiae. However, there is no report on their function in glucose sensing or transport. In this study, we investigated two hexose transporter-like proteins (Hxs1 and Hxs2) in Cryptococcus that share the highest sequence identity with the glucose sensors Snf3 and Rgt2 in S. cerevisiae. The expression of HXS1 is repressed by high glucose, while the HXS2 expression is not regulated by glucose. Functional studies showed that Hxs1 is required for fungal resistance to oxidative stress and fungal virulence. The hxs1Δ mutant exhibited a significant reduction in glucose uptake activity, indicating that Hxs1 is required for glucose uptake. Heterologous expression of Cryptococcus HXS1 rendered the S. cerevisiae mutant lacking all 20 hexose transporters a high glucose uptake activity, demonstrating that Hxs1 functions as a glucose transporter. Heterologous expression of HXS1 in the snf3Δ rgt2Δ double mutant did not complement its growth in YPD medium containing the respiration inhibitor antimycin A, suggesting that Hxs1 may not function as a glucose sensor. Taken together, our results demonstrate that Hxs1 is a high-affinity glucose transporter and required for fungal virulence. PMID:23691177

  15. Adiponectin attenuates high glucose-induced apoptosis through the AMPK/p38 MAPK signaling pathway in NRK-52E cells.

    Science.gov (United States)

    Wang, Yuanyuan; Zhang, Juan; Zhang, Lian; Gao, Ping; Wu, Xiaoyan

    2017-01-01

    Excessive apoptosis of proximal tubule cell is closely related to the development of diabetes. Recent evidence suggests that adiponectin (ADPN) protects cells from high glucose induced apoptosis. However, the precise mechanisms remain poorly understood. We sought to investigate the role of p38 mitogen-activated protein kinase (p38 MAPK) and AMP activated protein kinase (AMPK) in anti-apoptotic of adiponectin under high glucose condition in rat tubular NRK-52E cells. Cells were cultured in constant and oscillating high glucose media with or without recombinant rat adiponectin for 48 h. Cell counting kit-8 (CCK-8) was used to detect cell viability, flow cytometry and Hoechst Staining were applied to investigate cell apoptosis, and western blotting was used to examine protein expression, such as phospho-AMPK and phospho-p38MAPK. Exposure to oscillating high glucose exerted lower cell viability and higher early apoptosis than constant high glucose, which were both partially prevented by adiponectin. Further studies revealed that adiponectin suppressed p38MAPK phosphorylation, but led to an increase in AMPK α phosphorylation. Compared to stable high glucose group, blockage of p38MAPK cascade with SB203580 attenuated apoptosis significantly, but failed to affect the phosphorylation level of AMPK. While AMPK inhibitor, Compound C, increased apoptosis and remarkably inhibited the p38MAPK phosphorylation. Adiponectin exert a crucial protective role against apoptosis induced by high glucose via AMPK/p38MAPK pathway.

  16. Increased oxidative stress and toxicity in ADH and CYP2E1 overexpressing human hepatoma VL-17A cells exposed to high glucose.

    Science.gov (United States)

    Chandrasekaran, Karthikeyan; Swaminathan, Kavitha; Kumar, S Mathan; Clemens, Dahn L; Dey, Aparajita

    2012-05-01

    High glucose mediated oxidative stress and cell death is a well documented phenomenon. Using VL-17A cells which are HepG2 cells over-expressing alcohol dehydrogenase (ADH) and cytochrome P450 2E1 (CYP2E1) and control HepG2 cells, the association of ADH and CYP2E1 with high glucose mediated oxidative stress and toxicity in liver cells was investigated. Cell viability was measured and apoptosis or necrosis was determined through caspase-3 activity, Annexin V-propidium iodide staining and detecting decreases in mitochondrial membrane potential. Reactive oxygen species, lipid peroxidation and the formation of advanced glycated-end products were assessed. The levels of several antioxidants which included glutathione, glutathione peroxidase, catalase and superoxide dismutase were altered in high glucose treated VL-17A cells. Greater toxicity was observed in VL-17A cells exposed to high glucose when compared to HepG2 cells. Oxidative stress parameters were greatly increased in high glucose exposed VL-17A cells and apoptotic cell death was observed. Inhibition of CYP2E1 or caspase 3 or addition of the antioxidant trolox led to significant decreases in high glucose mediated oxidative stress and toxicity. Thus, the over-expression of ADH and CYP2E1 in liver cells is associated with increased high glucose mediated oxidative stress and toxicity.

  17. Aldosterone aggravates glucose intolerance induced by high fructose.

    Science.gov (United States)

    Sherajee, Shamshad J; Rafiq, Kazi; Nakano, Daisuke; Mori, Hirohito; Kobara, Hideki; Hitomi, Hirofumi; Fujisawa, Yoshihide; Kobori, Hiroyuki; Masaki, Tsutomu; Nishiyama, Akira

    2013-11-15

    We previously reported that aldosterone impaired vascular insulin signaling in vivo and in vitro. Fructose-enriched diet induces metabolic syndrome including hypertension, insulin resistance, hyperlipidemia and diabetes in animal. In the current study, we hypothesized that aldosterone aggravated fructose feeding-induced glucose intolerance in vivo. Rats were divided into five groups for six-week treatment; uninephrectomy (Unx, n=8), Unx+aldosterone (aldo, 0.75 µg/h, s.c., n=8), Unx+fructose (fruc, 10% in drinking water, n=8), Unx+aldo+fruc, (aldo+fruc, n=8), and Unx+aldo+fruc+spironolactone, a mineralocorticoid receptor antagonist (aldo+fruc+spiro, 20mg/kg/day, p.o., n=8). Aldo+fruc rats manifested the hypertension, and induced glucose intolerance compared to fruc intake rats assessed by oral glucose tolerance test, homeostasis model assessment of insulin resistance and hyperinsulinemic-euglycemic clamp study. Spironolactone, significantly improved the aldosterone-accelerated glucose intolerance. Along with improvement in insulin resistance, spironolactone suppressed upregulated mineralocorticoid receptor (MR) target gene, serum and glucocorticoid-regulated kinases-1 mRNA expression in skeletal muscle in aldo+fruc rats. In conclusion, these data suggested that aldosterone aggravates fructose feeding-induced glucose intolerance through MR activation.

  18. Dynamin-related protein inhibitor downregulates reactive oxygen species levels to indirectly suppress high glucose-induced hyperproliferation of vascular smooth muscle cells

    Energy Technology Data Exchange (ETDEWEB)

    Maimaitijiang, Alimujiang; Zhuang, Xinyu; Jiang, Xiaofei; Li, Yong, E-mail: 11211220031@fudan.edu.cn

    2016-03-18

    Hyperproliferation of vascular smooth muscle cells is a pathogenic mechanism common in diabetic vascular complications and is a putatively important therapeutic target. This study investigated multiple levels of biology, including cellular and organellar changes, as well as perturbations in protein synthesis and morphology. Quantitative and qualitative analysis was utilized to assess the effect of mitochondrial dynamic changes and reactive oxygen species(ROS) levels on high-glucose-induced hyperproliferation of vascular smooth muscle cells. The data demonstrated that the mitochondrial fission inhibitor Mdivi-1 and downregulation of ROS levels both effectively inhibited the high-glucose-induced hyperproliferation of vascular smooth muscle cells. Downregulation of ROS levels played a more direct role and ROS levels were also regulated by mitochondrial dynamics. Increased ROS levels induced excessive mitochondrial fission through dynamin-related protein (Drp 1), while Mdivi-1 suppressed the sensitivity of Drp1 to ROS levels, thus inhibiting excessive mitochondrial fission under high-glucose conditions. This study is the first to propose that mitochondrial dynamic changes and ROS levels interact with each other and regulate high-glucose-induced hyperproliferation of vascular smooth muscle cells. This finding provides novel ideas in understanding the pathogenesis of diabetic vascular remodeling and intervention. - Highlights: • Mdivi-1 inhibits VSMC proliferation by lowering ROS level in high-glucose condition. • ROS may be able to induce mitochondrial fission through Drp1 regulation. • Mdivi-1 can suppress the sensitivity of Drp1 to ROS.

  19. Angiopoietin-1 protects myocardial endothelial cell function blunted by angiopoietin-2 and high glucose condition

    Institute of Scientific and Technical Information of China (English)

    Qin-hui TUO; Guo-zuo XIONG; Heng ZENG; Hei-di YU; Shao-wei SUN; Hong-yan LING; Bing-yang ZHU; Duan-fang LIAO; Jian-xiong CHEN

    2011-01-01

    Aim:To evaluate the effects of angiopoietin-1 (Ang-1) on myocardial endothelial cell function under high glucose (HG) condition.Methods:Mouse heart myocardial endothelial cells (MHMECs) were cultured and incubated under HG (25 mmol/L) or normal glucose (NG, 5 mmol/L) conditions for 72 h. MTT was used to determine cellular viability, and TUNEL assay and caspase-3 enzyme linked immunosorbent assays were used to assay endothelial apoptosis induced by serum starvation. Immunoprecipitation and Western blot analysis were used to analyze protein phosphorylation and expression. Endothelial tube formation was used as an in vitro assay for angiogenesis.Results:Exposure of MHMECs to HG resulted in dramatic decreases in phosphorylation of the Tie-2 receptor and its downstream signaling partners, Akt/eNOS, compared to that under NG conditions. Ang-1 (250 ng/mL) increased Tie-2 activation, inhibited cell apoptosis, and promoted angiogenesis. Ang-1-mediated protection of endothelial function was blunted by Ang-2 (25 ng/mL).Conclusion:Ang-1 activates the Tie-2 pathway and restores hyperglycemia-induced myocardial microvascular endothelial dysfunction.This suggests a protective role of Ang-1 in the ischemic myocardium, particularly in hearts affected by hyperglycemia or diabetes.

  20. In vivo inhibition of incorporation of (U-/sup 14/C)glucose into proteins in experimental focal epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Coutinho-Netto, J.; Boyar, M.M.; Abdul-Ghani, A.S.; Bradford, H.F.

    1982-08-01

    The in vivo incorporation of (/sup 14/C) from (U-/sup 14/C)-glucose into rat brain proteins from different cortical areas was examined in three different experimental focal epilepsies: cobalt, freeze-lesions, and tityustoxin. When (U-/sup 14/C)-glucose was injected intraperitoneally into awake and unrestrained animals with marked signs of epileptic hyperactivity, the inhibition of incorporation of (/sup 14/C)-amino acids into trichloracetic acid (TCA)-insoluble proteins was highest in the focal (sensorimotor) area when compared with distant regions (approx. 60%), but less when compared with the contralateral (sensorimotor) region (approx. 23%). Greatly decreased incorporation caused by both cobalt and freeze-lesion-induced epilepsies was also observed in the contralateral area when a comparison was made with distant regions (approx. 50%), but there were no significant differences in protein-specific radioactivity between the different distant areas.

  1. NFAT2 mediates high glucose-induced glomerular podocyte apoptosis through increased Bax expression

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ruizhao, E-mail: liruizhao1979@126.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Zhang, Li, E-mail: Zhanglichangde@163.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Southern Medical University, Guangzhou, Guangdong (China); Shi, Wei, E-mail: shiwei.gd@139.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Zhang, Bin, E-mail: zhangbinyes@yahoo.com.cn [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Liang, Xinling, E-mail: xinlingliang@yahoo.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Liu, Shuangxin, E-mail: mplsxi@yahoo.com.cn [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China); Wang, Wenjian, E-mail: wwjph@yahoo.com [Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, 510080 (China)

    2013-04-15

    Background: Hyperglycemia promotes podocyte apoptosis and plays a key role in the pathogenesis of diabetic nephropathy. However, the mechanisms that mediate hyperglycemia-induced podocyte apoptosis is still far from being fully understood. Recent studies reported that high glucose activate nuclear factor of activated T cells (NFAT) in vascular smooth muscle or pancreatic β-cells. Here, we sought to determine if hyperglycemia activates NFAT2 in cultured podocyte and whether this leads to podocyte apoptosis. Meanwhile, we also further explore the mechanisms of NFAT2 activation and NFAT2 mediates high glucose-induced podocyte apoptosis. Methods: Immortalized mouse podocytes were cultured in media containing normal glucose (NG), or high glucose (HG) or HG plus cyclosporine A (a pharmacological inhibitor of calcinerin) or 11R-VIVIT (a special inhibitor of NFAT2). The activation of NFAT2 in podocytes was detected by western blotting and immunofluorescence assay. The role of NFAT2 in hyperglycemia-induced podocyte apoptosis was further evaluated by observing the inhibition of NFAT2 activation by 11R-VIVIT using flow cytometer. Intracellular Ca{sup 2+} was monitored in HG-treated podcocytes using Fluo-3/AM. The mRNA and protein expression of apoptosis gene Bax were measured by real time-qPCR and western blotting. Results: HG stimulation activated NFAT2 in a time- and dose-dependent manner in cultured podocytes. Pretreatment with cyclosporine A (500 nM) or 11R-VIVIT (100 nM) completely blocked NFAT2 nuclear accumulation. Meanwhile, the apoptosis effects induced by HG were also abrogated by concomitant treatment with 11R-VIVIT in cultured podocytes. We further found that HG also increased [Ca{sup 2+}]i, leading to activation of calcineurin, and subsequent increased nuclear accumulation of NFAT2 and Bax expression in cultured podocytes. Conclusion: Our results identify a new finding that HG-induced podocyte apoptosis is mediated by calcineurin/NFAT2/Bax signaling pathway

  2. Sodium-glucose cotransporter inhibition: therapeutic potential for the treatment of type 2 diabetes mellitus.

    Science.gov (United States)

    Raskin, Philip

    2013-07-01

    Results from randomized controlled trials have demonstrated that the risk of microvascular complications can be reduced by intensive glycaemic control in patients with type 2 diabetes mellitus (T2DM). However, only about half of patients with diagnosed diabetes achieve recommended glycaemic goals. New therapies with complementary mechanisms of action that are independent of insulin secretion or action may provide additional therapeutic options to enable patients to achieve glycaemic control. The kidney plays an important role in glucose homeostasis, primarily by the reabsorption of filtered glucose. The sodium-glucose cotransporter 2 (SGLT2), located in the proximal convoluted tubule, is responsible for the majority of glucose reabsorption by the kidney. SGLT2 inhibitors offer a novel approach to treat T2DM and reduce hyperglycaemia by increasing urinary excretion of glucose. Dapagliflozin, an SGLT2 inhibitor recently approved in Europe for the treatment of T2DM, improves glycaemic control in patients with T2DM when used as monotherapy or when added to other diabetes medications, such as metformin, sulfonylureas, pioglitazone, and insulin. As a class, SGLT2 inhibitors are well tolerated and have a low propensity to cause hypoglycaemia. An increase in signs, symptoms, and other events suggestive of genital and, in some studies, urinary tract infections has been reported with SGLT2 inhibitors. Results from ongoing and future clinical trials will help define the role for this new class of investigational compounds, with its unique mechanism of action, as a treatment option for reducing hyperglycaemia in patients with T2DM.

  3. Glucagon-like peptide 1 receptor agonist protects high-glucose inducedβcells apoptosis via inhibition of NOX2-dependent ROS production%GLP-1Ra减少高糖诱导的β细胞凋亡作用机制探讨

    Institute of Scientific and Technical Information of China (English)

    丁敏; 李春君; 邢云芝; 于倩; 王鹏华; 于德民

    2015-01-01

    Objective To investigate the possible mechanisms of glucagon-like peptide 1 receptor agonists (GLP-1Ra) protection against hyperglycemic induced beta cell apoptosis through depression of NOX2-dependent ROS production. Methods The rat model of type 2 diabetes (T2DM) was established by injecting small doses of streptozotocin (STZ) fol⁃lowed by 8-week high fat diet. The experimental animals were divided into three groups:normal control (N) group, diabetes (T2DM) group and GLP-1Ra group [treated with liraglutide 200 μg/(kg · d)for 12 weeks]. The blood glucose levels were compared before and after modeling, before treatment and 12-week after treatment with GLP-1Ra. The level of glycosylated hemoglobin (HbA1c) was detected by high-pressure liquid chromatography. Automatic biochemical analyzer was used to de⁃tect levels of aspertate aminotransferase (AST), creatinine (CR) and urea nitrogen (BUN). The apoptotic rates of islets were determined by TUNEL method and cleaved caspase 3 was detected by immunohistochemistry. DCFH-DA fluorescent probe was used to detect reactive oxygen species (ROS) levels of islets. Levels of NADPH oxidase (NOX) catalytic subunit (NOX 2) in islets were measured by immunohistochemistry. Results At the end of the study, glycemic control (average blood glucose/week and HbA1c) and lipid situation were improved significantly in the GLP-1Ra group than those of N group (P0.05). After application Apocynin for inhibition, there were no significant differences between three groups (P>0.05). The level of NOX2 was significantly lower in GLP-1Ra group compared to that of T2DM group (P<0.05). Conclusion GLP-1Ra can inhibit apoptosis ofβcells in diabetes rat, and the depression of NOX2-dependent ROS may be one of the important underly⁃ing mechanisms.%目的:探讨胰高血糖素样肽-1(GLP-1)受体激动剂(GLP-1Ra)减少高糖诱导的β细胞凋亡作用的可能机制。方法正常对照(N,普通饲料喂养)组、2型糖尿病(T2

  4. Osteocalcin protects pancreatic beta cell function and survival under high glucose conditions

    Energy Technology Data Exchange (ETDEWEB)

    Kover, Karen, E-mail: kkover@cmh.edu [Division of Endocrine/Diabetes, Children' s Mercy Hospital & Clinics, Kansas City, MO 64108 (United States); University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108 (United States); Yan, Yun; Tong, Pei Ying; Watkins, Dara; Li, Xiaoyu [Division of Endocrine/Diabetes, Children' s Mercy Hospital & Clinics, Kansas City, MO 64108 (United States); University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108 (United States); Tasch, James; Hager, Melissa [Kansas City University Medical Biosciences, Kansas City, MO (United States); Clements, Mark; Moore, Wayne V. [Division of Endocrine/Diabetes, Children' s Mercy Hospital & Clinics, Kansas City, MO 64108 (United States); University of Missouri-Kansas City School of Medicine, Kansas City, MO 64108 (United States)

    2015-06-19

    Diabetes is characterized by progressive beta cell dysfunction and loss due in part to oxidative stress that occurs from gluco/lipotoxicity. Treatments that directly protect beta cell function and survival in the diabetic milieu are of particular interest. A growing body of evidence suggests that osteocalcin, an abundant non-collagenous protein of bone, supports beta cell function and proliferation. Based on previous gene expression data by microarray, we hypothesized that osteocalcin protects beta cells from glucose-induced oxidative stress. To test our hypothesis we cultured isolated rat islets and INS-1E cells in the presence of normal, high, or high glucose ± osteocalcin for up to 72 h. Oxidative stress and viability/mitochondrial function were measured by H{sub 2}O{sub 2} assay and Alamar Blue assay, respectively. Caspase 3/7 activity was also measured as a marker of apoptosis. A functional test, glucose stimulated insulin release, was conducted and expression of genes/protein was measured by qRT-PCR/western blot/ELISA. Osteocalcin treatment significantly reduced high glucose-induced H{sub 2}O{sub 2} levels while maintaining viability/mitochondrial function. Osteocalcin also significantly improved glucose stimulated insulin secretion and insulin content in rat islets after 48 h of high glucose exposure compared to untreated islets. As expected sustained high glucose down-regulated gene/protein expression of INS1 and BCL2 while increasing TXNIP expression. Interestingly, osteocalcin treatment reversed the effects of high glucose on gene/protein expression. We conclude that osteocalcin can protect beta cells from the negative effects of glucose-induced oxidative stress, in part, by reducing TXNIP expression, thereby preserving beta cell function and survival. - Highlights: • Osteocalcin reduces glucose-induced oxidative stress in beta cells. • Osteocalcin preserves beta cell function and survival under stress conditions. • Osteocalcin reduces glucose

  5. Glucose transporter-8 (GLUT8) mediates glucose intolerance and dyslipidemia in high-fructose diet-fed male mice.

    Science.gov (United States)

    DeBosch, Brian J; Chen, Zhouji; Finck, Brian N; Chi, Maggie; Moley, Kelle H

    2013-11-01

    Members of the glucose transporter (GLUT) family of membrane-spanning hexose transporters are subjects of intensive investigation for their potential as modifiable targets to treat or prevent obesity, metabolic syndrome, and type 2 diabetes mellitus. Mounting evidence suggests that the ubiquitously expressed class III dual-specificity glucose and fructose transporter, GLUT8, has important metabolic homeostatic functions. We therefore tested the hypothesis that GLUT8 mediates the deleterious metabolic effects of chronic high-fructose diet exposure. Here we demonstrate resistance to high-fructose diet-induced glucose intolerance and dyslipidemia concomitant with enhanced oxygen consumption and thermogenesis in GLUT8-deficient male mice. Independent of diet, significantly lower systolic blood pressure both at baseline and after high-fructose diet feeding was also observed by tail-cuff plethysmography in GLUT8-deficient mice vs wild-type controls. Resistance to fructose-induced metabolic dysregulation occurred in the context of enhanced hepatic peroxisome proliferator antigen receptor-γ (PPARγ) protein abundance, whereas in vivo hepatic adenoviral GLUT8 overexpression suppressed hepatic PPARγ expression. Taken together, these findings suggest that GLUT8 blockade prevents fructose-induced metabolic dysregulation, potentially by enhancing hepatic fatty acid metabolism through PPARγ and its downstream targets. We thus establish GLUT8 as a promising target in the prevention of diet-induced obesity, metabolic syndrome, and type 2 diabetes mellitus in males.

  6. Glucose inhibits the insulin-induced activation of the insulin-degrading enzyme in HepG2 cells.

    Science.gov (United States)

    Pivovarova, O; Gögebakan, O; Pfeiffer, A F H; Rudovich, N

    2009-08-01

    Hepatic insulin degradation decreases in type 2 diabetes. Insulin-degrading enzyme (IDE) plays a key role in insulin degradation and its gene is located in a diabetes-associated chromosomal region. We hypothesised that IDE may be regulated by insulin and/or glucose in a liver cell model. To validate the observed regulation of IDE in vivo, we analysed biopsies of human adipose tissue during different clamp experiments in men. Human hepatoma HepG2 cells were incubated in normal (1 g/l) or high (4.5 g/l) glucose medium and treated with insulin for 24 h. Catalytic activity, mRNA and protein levels of IDE were assessed. IDE mRNA levels were measured in biopsies of human subcutaneous adipose tissue before and at 240 min of hyperinsulinaemic, euglycaemic and hyperglycaemic clamps. In HepG2 cells, insulin increased IDE activity under normal glucose conditions with no change in IDE mRNA or protein levels. Under conditions of high glucose, insulin increased mRNA levels of IDE without changes in IDE activity. Both in normal and high glucose medium, insulin increased levels of the catalytically more active 15a IDE isoform compared with the 15b isoform. In subcutaneous adipose tissue, IDE mRNA levels were not significantly upregulated after euglycaemic or hyperglycaemic clamps. Insulin increases IDE activity in HepG2 cells in normal but not in high glucose conditions. This disturbance cannot be explained by corresponding alterations in IDE protein levels or IDE splicing. The loss of insulin-induced regulation of IDE activity under hyperglycaemia may contribute to the reduced insulin extraction and peripheral hyperinsulinaemia in type 2 diabetes.

  7. Antioxidants improve impaired insulin-mediated glucose uptake and prevent migration and proliferation of cultured rabbit coronary smooth muscle cells induced by high glucose.

    Science.gov (United States)

    Yasunari, K; Kohno, M; Kano, H; Yokokawa, K; Minami, M; Yoshikawa, J

    1999-03-16

    To explore the role of intracellular oxidative stress in high glucose-induced atherogenesis, we examined the effect of probucol and/or alpha-tocopherol on the migration and growth characteristics of cultured rabbit coronary vascular smooth muscle cells (VSMCs). Chronic high-glucose-medium (22. 2 mmol/L) treatment increased platelet-derived growth factor (PDGF)-BB-mediated VSMC migration, [3H]thymidine incorporation, and cell number compared with VSMCs treated with normal-glucose medium (5.6 mmol/L+16.6 mmol/L mannose). Probucol and alpha-tocopherol significantly suppressed high glucose-induced increase in VSMC migration, cell number, and [3H]thymidine incorporation. Probucol and alpha-tocopherol suppressed high glucose-induced elevation of the cytosolic ratio of NADH/NAD+, phospholipase D, and membrane-bound protein kinase C activation. Probucol, alpha-tocopherol, and calphostin C improved the high glucose-induced suppression of insulin-mediated [3H]deoxyglucose uptake. Chronic high-glucose treatment increased the oxidative stress, which was significantly suppressed by probucol, alpha-tocopherol, suramin, and calphostin C. These findings suggest that probucol and alpha-tocopherol may suppress high glucose-induced VSMC migration and proliferation via suppression of increases in the cytosolic ratio of free NADH/NAD+, phospholipase D, and protein kinase C activation induced by high glucose, which result in reduction in intracellular oxidative stress.

  8. Portal vein glucose entry triggers a coordinated cellular response that potentiates hepatic glucose uptake and storage in normal but not high-fat/high-fructose-fed dogs.

    Science.gov (United States)

    Coate, Katie C; Kraft, Guillaume; Irimia, Jose M; Smith, Marta S; Farmer, Ben; Neal, Doss W; Roach, Peter J; Shiota, Masakazu; Cherrington, Alan D

    2013-02-01

    The cellular events mediating the pleiotropic actions of portal vein glucose (PoG) delivery on hepatic glucose disposition have not been clearly defined. Likewise, the molecular defects associated with postprandial hyperglycemia and impaired hepatic glucose uptake (HGU) following consumption of a high-fat, high-fructose diet (HFFD) are unknown. Our goal was to identify hepatocellular changes elicited by hyperinsulinemia, hyperglycemia, and PoG signaling in normal chow-fed (CTR) and HFFD-fed dogs. In CTR dogs, we demonstrated that PoG infusion in the presence of hyperinsulinemia and hyperglycemia triggered an increase in the activity of hepatic glucokinase (GK) and glycogen synthase (GS), which occurred in association with further augmentation in HGU and glycogen synthesis (GSYN) in vivo. In contrast, 4 weeks of HFFD feeding markedly reduced GK protein content and impaired the activation of GS in association with diminished HGU and GSYN in vivo. Furthermore, the enzymatic changes associated with PoG sensing in chow-fed animals were abolished in HFFD-fed animals, consistent with loss of the stimulatory effects of PoG delivery. These data reveal new insight into the molecular physiology of the portal glucose signaling mechanism under normal conditions and to the pathophysiology of aberrant postprandial hepatic glucose disposition evident under a diet-induced glucose-intolerant condition.

  9. Negative Effects of High Glucose Exposure in Human Gonadotropin-Releasing Hormone Neurons

    Directory of Open Access Journals (Sweden)

    Annamaria Morelli

    2013-01-01

    Full Text Available Metabolic disorders are often associated with male hypogonadotropic hypogonadism, suggesting that hypothalamic defects involving GnRH neurons may impair the reproductive function. Among metabolic factors hyperglycemia has been implicated in the control of the reproductive axis at central level, both in humans and in animal models. To date, little is known about the direct effects of pathological high glucose concentrations on human GnRH neurons. In this study, we investigated the high glucose effects in the human GnRH-secreting FNC-B4 cells. Gene expression profiling by qRT-PCR, confirmed that FNC-B4 cells express GnRH and several genes relevant for GnRH neuron function (KISS1R, KISS1, sex steroid and leptin receptors, FGFR1, neuropilin 2, and semaphorins, along with glucose transporters (GLUT1, GLUT3, and GLUT4. High glucose exposure (22 mM; 40 mM significantly reduced gene and protein expression of GnRH, KISS1R, KISS1, and leptin receptor, as compared to normal glucose (5 mM. Consistent with previous studies, leptin treatment significantly induced GnRH mRNA expression at 5 mM glucose, but not in the presence of high glucose concentrations. In conclusion, our findings demonstrate a deleterious direct contribution of high glucose on human GnRH neurons, thus providing new insights into pathogenic mechanisms linking metabolic disorders to reproductive dysfunctions.

  10. Berberine attenuates high glucose-induced proliferation and extracellular matrix accumulation in mesangial cells: involvement of suppression of cell cycle progression and NF-κB/AP-1 pathways.

    Science.gov (United States)

    Lan, Tian; Wu, Teng; Chen, Cheng; Chen, Xiaolan; Hao, Jie; Huang, Junying; Wang, Lijing; Huang, Heqing

    2014-03-25

    Berberine has been shown to have renoprotective effects on diabetes through attenuating TGF-β1 and fibronectin (FN) expression. However, how berberine regulates TGF-β1 and FN is not fully clear. Here we investigated whether berberine inhibited TGF-β1 and FN expression in high glucose-cultured mesangial cells. Berberine significantly inhibited mesangial cell proliferation and hypertrophy by increasing the cell population in G1-phase and reducing that in S-phase. In addition, berberine reversed high glucose-induced down-regulation of cyclin-dependent kinase inhibitor p21(Waf1)/(Cip1) and p27(Kip1). Berberine inhibited p65 translocation to the nucleus and c-jun phosphorylation induced by high glucose. Furthermore, berberine attenuated high glucose-induced expression of TGF-β1 and FN. Using a luciferase reporter assay, we found that high glucose-induced transcription activity of NF-κB and AP-1 was blocked by berberine. Electrophoretic mobility shift assay showed that high glucose increased that NF-κB and AP-1 DNA binding activity. These data indicate that berberine inhibited mesangial cell proliferation and hypertrophy by modulating cell cycle progress. In addition, berberine suppressed high glucose-induced TGF-β1 and FN expression by blocking NF-κB/AP-1 pathways.

  11. Wortmannin inhibits both insulin- and contraction-stimulated glucose uptake and transport in rat skeletal muscle

    DEFF Research Database (Denmark)

    Wojtaszewski, Jørgen; Hansen, B F; Ursø, Birgitte

    1996-01-01

    The role of phosphatidylinositol (PI) 3-kinase for insulin- and contraction-stimulated muscle glucose transport was investigated in rat skeletal muscle perfused with a cell-free perfusate. The insulin receptor substrate-1-associated PI 3-kinase activity was increased sixfold upon insulin stimulat...

  12. High performance separation of xylose and glucose by enzyme assisted nanofiltration

    DEFF Research Database (Denmark)

    Morthensen, Sofie Thage; Luo, Jianquan; Meyer, Anne S.;

    2015-01-01

    of the integrated system. Full conversion of glucose to gluconic acid assisted by glucose oxidase (GOD) could be achieved by coupling a parallel reaction catalyzed by catalase (CAT), where H2O2 (GOD-inhibitor formed in the first reaction) was decomposed to water and oxygen. GOD has a high oxygen...

  13. Heme oxygenase-1 enhances autophagy in podocytes as a protective mechanism against high glucose-induced apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Chenglong [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Zheng, Haining [Department of Hyperbaric Oxygen, Nanjing General Hospital of Nanjing Military Command, Nanjing (China); Huang, Shanshan; You, Na; Xu, Jiarong; Ye, Xiaolong; Zhu, Qun; Feng, Yamin; You, Qiang; Miao, Heng [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Ding, Dafa, E-mail: dingdafa2004@aliyun.com [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China); Lu, Yibing, E-mail: luyibing2004@126.com [Department of Endocrinology, The Second Affiliated Hospital of Nanjing Medical University, Nanjing (China)

    2015-10-01

    Injury and loss of podocytes play vital roles in diabetic nephropathy progression. Emerging evidence suggests autophagy, which is induced by multiple stressors including hyperglycemia, plays a protective role. Meanwhile, heme oxygenase-1 (HO-1) possesses powerful anti-apoptotic properties. Therefore, we investigated the impact of autophagy on podocyte apoptosis under diabetic conditions and its association with HO-1. Mouse podocytes were cultured in vitro; apoptosis was detected by flow cytometry. Transmission electron microscopy and biochemical autophagic flux assays were used to measure the autophagy markers microtubule-associated protein 1 light chain 3-II (LC3-II) and beclin-1. LC3-II and beclin-1 expression peaked 12–24 h after exposing podocytes to high glucose. Inhibition of autophagy with 3-methyladenine or Beclin-1 siRNAs or Atg 5 siRNAs sensitized cells to apoptosis, suggesting autophagy is a survival mechanism. HO-1 inactivation inhibited autophagy, which aggravated podocyte injury in vitro. Hemin-induced autophagy also protected podocytes from hyperglycemia in vitro and was abrogated by HO-1 siRNA. Adenosine monophosphate-activated protein kinase phosphorylation was higher in hemin-treated and lower in HO-1 siRNA-treated podocytes. Suppression of AMPK activity reversed HO-1-mediated Beclin-1 upregulation and autophagy, indicating HO-1-mediated autophagy is AMPK dependent. These findings suggest HO-1 induction and regulation of autophagy are potential therapeutic targets for diabetic nephropathy. - Highlights: • High glucose leads to increased autophagy in podocytes at an early stage. • The early autophagic response protects against high glucose-induced apoptosis. • Heme oxygenase-1 enhances autophagy and decreases high glucose -mediated apoptosis. • Heme oxygenase-1 induces autophagy through the activation of AMPK.

  14. Isoferulic Acid, a New Anti-Glycation Agent, Inhibits Fructose- and Glucose-Mediated Protein Glycation in Vitro

    Directory of Open Access Journals (Sweden)

    Sirichai Adisakwattana

    2013-05-01

    Full Text Available The inhibitory activity of isoferulic acid (IFA on fructose- and glucose-mediated protein glycation and oxidation of bovine serum albumin (BSA was investigated. Our data showed that IFA (1.25–5 mM inhibited the formation of fluorescent advanced glycation end products (AGEs and non-fluorescent AGE [Nε-(carboxymethyl lysine: CML], as well as the level of fructosamine. IFA also prevented protein oxidation of BSA indicated by decreasing protein carbonyl formation and protein thiol modification. Furthermore, IFA suppressed the formation of β-cross amyloid structures of BSA. Therefore, IFA might be a new promising anti-glycation agent for the prevention of diabetic complications via inhibition of AGEs formation and oxidation-dependent protein damage.

  15. Impact of a Combined High Cholesterol Diet and High Glucose Environment on Vasculature

    Science.gov (United States)

    Cui, Taixing; Tang, Dongqi; Wang, Xing Li

    2013-01-01

    Aims Vascular complications are the leading cause of mortality and morbidity in patients with diabetes. However, proper animal models of diabetic vasculopathy that recapitulate the accelerated progression of vascular lesions in human are unavailable. In the present study, we developed a zebrafish model of diabetic vascular complications and the methodology for quantifying vascular lesion formation real-time in the living diabetic zebrafish. Methods and Results Wild type zebrafish (AB) and transgenic zebrafish lines of fli1:EGFP, lyz:EGFP, gata1:dsRed, double transgenic zebrafish of gata1:dsRed/fli1:EGFP were exposed to high cholesterol diet and 3% glucose (HCD-HG) for 10 days. The zebrafish model with HCD-HG treatment was characterized by significantly increased tissue levels of insulin, glucagon, glucose, total triglyceride and cholesterol. Confocal microscopic analysis further revealed that the diabetic larvae developed clearly thickened endothelial layers, distinct perivascular lipid depositions, substantial accumulations of inflammatory cells in the injured vasculature, and a decreased velocity of blood flow. Moreover, the vascular abnormalities were improved by the treatment of pioglitazone and metformin. Conclusion A combination of high cholesterol diet and high glucose exposure induces a rapid onset of vascular complications in zebrafish similar to the early atherosclerotic vascular injuries in mammalian diabetic models, suggesting that zebrafish may be used as a novel animal model for diabetic vasculopathy. PMID:24349075

  16. Suppression of renal fibrosis by galectin-1 in high glucose-treated renal epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Okano, Kazuhiro, E-mail: kaokano@kc.twmu.ac.jp; Tsuruta, Yuki; Yamashita, Tetsuri; Takano, Mari; Echida, Yoshihisa; Nitta, Kosaku

    2010-11-15

    Diabetic nephropathy is the most common cause of chronic kidney disease. We investigated the ability of intracellular galectin-1 (Gal-1), a prototype of endogenous lectin, to prevent renal fibrosis by regulating cell signaling under a high glucose (HG) condition. We demonstrated that overexpression of Gal-1 reduces type I collagen (COL1) expression and transcription in human renal epithelial cells under HG conditions and transforming growth factor-{beta}1 (TGF-{beta}1) stimulation. Matrix metalloproteinase 1 (MMP1) is stimulated by Gal-1. HG conditions and TGF-{beta}1 treatment augment expression and nuclear translocation of Gal-1. In contrast, targeted inhibition of Gal-1 expression reduces COL1 expression and increases MMP1 expression. The Smad3 signaling pathway is inhibited, whereas two mitogen-activated protein kinase (MAPK) pathways, p38 and extracellular signal-regulated kinase (ERK), are activated by Gal-1, indicating that Gal-1 regulates these signaling pathways in COL1 production. Using specific inhibitors of Smad3, ERK, and p38 MAPK, we showed that ERK MAPK activated by Gal-1 plays an inhibitory role in COL1 transcription and that activation of the p38 MAPK pathway by Gal-1 plays a negative role in MMP1 production. Taken together, two MAPK pathways are stimulated by increasing levels of Gal-1 in the HG condition, leading to suppression of COL1 expression and increase of MMP1 expression.

  17. The Effects of High Glucose on Adipogenic and Osteogenic Differentiation of Gestational Tissue-Derived MSCs

    Directory of Open Access Journals (Sweden)

    Weerawan Hankamolsiri

    2016-01-01

    Full Text Available Most type 2 diabetic patients are obese who have increased number of visceral adipocytes. Those visceral adipocytes release several factors that enhance insulin resistance making diabetic treatment ineffective. It is known that significant percentages of visceral adipocytes are derived from mesenchymal stem cells and high glucose enhances adipogenic differentiation of mouse bone marrow-derived MSCs (BM-MSCs. However, the effect of high glucose on adipogenic differentiation of human bone marrow and gestational tissue-derived MSCs is still poorly characterized. This study aims to investigate the effects of high glucose on proliferation as well as adipogenic and osteogenic differentiation of human MSCs derived from bone marrow and several gestational tissues including chorion, placenta, and umbilical cord. We found that high glucose reduced proliferation but enhanced adipogenic differentiation of all MSCs examined. The expression levels of some adipogenic genes were also upregulated when MSCs were cultured in high glucose. Although high glucose transiently downregulated the expression levels of some osteogenic genes examined, its effect on the osteogenic differentiation levels of the MSCs is not clearly demonstrated. The knowledge gained from this study will increase our understanding about the effect of high glucose on adipogenic differentiation of MSCs and might lead to an improvement in the diabetic treatment in the future.

  18. "The Role ofL-arginine in Control of Apoptosis in Preimplantation Mouse Embryos Cultured in High Glucose Media "

    Directory of Open Access Journals (Sweden)

    Mohammad Barbarestani

    2004-06-01

    Full Text Available Maternal hyperglycemia causes delay in early stages of embryonic growth and development, higher incidence of congenital malformations and spontaneous miscarriage compared with those of non-diabetic conditions. High glucosis tratogenicity seems to be related to reduction of Nitric Oxide production (NO in hyperglycemic condition. In order to test this hypothesis, 2-cell stage embryos of normal mice were cultured with high concentration of glucose (30mM and different concentrations of L-arginine (5,10,20 mM or L-NAME, an NO syntase (NOS inhibitor. In the end of culture, blastocysts were stained by by terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL technique and apoptotic cells were detected by using a Fluorescence microscope. Finally the amount of nitrite in the cultured media was assayed by Griess method. The results indicated that high glucose reduces Nitric Oxide production by preimplantation embryos and increases apoptosis of embryonic cells, but 5-20mM of L-arginine significantly increases Nitric Oxide production and decreases apoptosis. On the contrary L-NAME significantly inhibits the development of pre-implantation embryos. In conclusion, this study indicated that reduced nitric oxide production in high glucosis condition is a main factor for embryonic damage, and supplementation of high glucose media with L-arginine has an important role in prevention of high glucosis embryotoxicity

  19. Chronic reactive oxygen species exposure inhibits glucose uptake and causes insulin resistance in C2C12 myotubes.

    Science.gov (United States)

    Ding, Hongwen; Heng, Baoli; He, Wenfang; Shi, Liping; Lai, Caiyong; Xiao, Long; Ren, Haolin; Mo, Shijie; Su, Zexuan

    2016-09-16

    Reactive oxygen species (ROS) is an important regulator in cellular signaling transduction, and many previous studies have indicated that acute ROS stimulation improves insulin sensitivity in skeletal muscle. In the study, we found that chronic ROS treatment caused serious insulin resistance in C2C12 myotubes. Glucose uptake and consumption assay indicated that pretreatment with 80 μM H2O2 for 2 h inhibited insulin-stimulated glucose uptake in C2C12 myotubes, and the reason for it, is that chronic H2O2 treatment decreased insulin-induced glucose transporter 4 (GLUT4) translocation from cell plasma to cell membrane. Moreover, Akt2 phosphorylation depended on insulin was reduced in C2C12 myotubes of chronic H2O2 treatment. Together, this study provides further demonstration that chronic ROS stress is associated with insulin resistance of skeletal muscle in the progression of type 2 diabetes. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Heme Oxygenase-1 Protects Retinal Endothelial Cells against High Glucose- and Oxidative/Nitrosative Stress-Induced Toxicity

    Science.gov (United States)

    Castilho, Áurea F.; Aveleira, Célia A.; Leal, Ermelindo C.; Simões, Núria F.; Fernandes, Carolina R.; Meirinhos, Rita I.; Baptista, Filipa I.; Ambrósio, António F.

    2012-01-01

    Diabetic retinopathy is a leading cause of visual loss and blindness, characterized by microvascular dysfunction. Hyperglycemia is considered the major pathogenic factor for the development of diabetic retinopathy and is associated with increased oxidative/nitrosative stress in the retina. Since heme oxygenase-1 (HO-1) is an enzyme with antioxidant and protective properties, we investigated the potential protective role of HO-1 in retinal endothelial cells exposed to high glucose and oxidative/nitrosative stress conditions. Retinal endothelial cells were exposed to elevated glucose, nitric oxide (NO) and hydrogen peroxide (H2O2). Cell viability and apoptosis were assessed by MTT assay, Hoechst staining, TUNEL assay and Annexin V labeling. The production of reactive oxygen species (ROS) was detected by the oxidation of 2′,7′-dichlorodihydrofluorescein diacetate. The content of HO-1 was assessed by immunobloting and immunofluorescence. HO activity was determined by bilirubin production. Long-term exposure (7 days) of retinal endothelial cells to elevated glucose decreased cell viability and had no effect on HO-1 content. However, a short-time exposure (24 h) to elevated glucose did not alter cell viability, but increased both the levels of intracellular ROS and HO-1 content. Moreover, the inhibition of HO with SnPPIX unmasked the toxic effect of high glucose and revealed the protection conferred by HO-1. Oxidative/nitrosative stress conditions increased cell death and HO-1 protein levels. These effects of elevated glucose and HO inhibition on cell death were confirmed in primary endothelial cells (HUVECs). When cells were exposed to oxidative/nitrosative stress conditions there was also an increase in retinal endothelial cell death and HO-1 content. The inhibition of HO enhanced ROS production and the toxic effect induced by exposure to H2O2 and NOC-18 (NO donor). Overexpression of HO-1 prevented the toxic effect induced by H2O2 and NOC-18. In conclusion, HO-1

  1. Hyperuricemia Is a Risk Factor for the Onset of Impaired Fasting Glucose in Men with a High Plasma Glucose Level: A Community-Based Study

    Science.gov (United States)

    Miyake, Teruki; Kumagi, Teru; Furukawa, Shinya; Hirooka, Masashi; Kawasaki, Keitarou; Koizumi, Mitsuhito; Todo, Yasuhiko; Yamamoto, Shin; Abe, Masanori; Kitai, Kohichiro; Matsuura, Bunzo; Hiasa, Yoichi

    2014-01-01

    Background It is not clear whether elevated uric acid is a risk factor for the onset of impaired fasting glucose after stratifying by baseline fasting plasma glucose levels. We conducted a community-based retrospective longitudinal cohort study to clarify the relationship between uric acid levels and the onset of impaired fasting glucose, according to baseline fasting plasma glucose levels. Methods We enrolled 6,403 persons (3,194 men and 3,209 women), each of whom was 18–80 years old and had >2 annual check-ups during 2003–2010. After excluding persons who had fasting plasma glucose levels ≥6.11 mM and/or were currently taking anti-diabetic agents, the remaining 5,924 subjects were classified into quartiles according to baseline fasting plasma glucose levels. The onset of impaired fasting glucose was defined as fasting plasma glucose ≥6.11 mM during the observation period. Results In the quartile groups, 0.9%, 2.1%, 3.4%, and 20.2% of the men developed impaired fasting glucose, respectively, and 0.1%, 0.3%, 0.5%, and 5.6% of the women developed impaired fasting glucose, respectively (P trend fasting glucose in men with highest-quartile fasting plasma glucose levels (adjusted hazard ratio, 1.003; 95% confidence interval, 1.0001–1.005, P = 0.041). Conclusions Among men with high fasting plasma glucose, hyperuricemia may be independently associated with an elevated risk of developing impaired fasting glucose. PMID:25237894

  2. Enhancement of LPS-Induced Microglial Inflammation Response via TLR4 Under High Glucose Conditions

    Directory of Open Access Journals (Sweden)

    Xiang Zhang

    2015-03-01

    Full Text Available Background: Microglia activation mediated by toll-like receptor 4 (TLR4 plays an important role in neuroinflammation and postoperative cognitive dysfunction (POCD. Diabetes mellitus (DM has been recently suggested as an independent risk factor for POCD. In this study, we investigate the potential exacerbation of the inflammatory response in primary microglia due to high glucose conditions. Methods: Primary microglial cells were exposed to normal glucose (25 mmol/L and high glucose (35 mmol/L levels alone or with lipopolyscaccharide (LPS 0, 2, 5, 10 ng/mL. The pro-inflammatory response of the cells was assessed by measuring changes in cytokine levels and the evaluation of associated signaling pathways. Results: Neither high glucose nor low LPS (≤5ng/ml alone had an effect on TNF-a and IL-6 levels, but the combination of low LPS and high glucose stimulated the inflammatory response. Analyses of the associated signaling pathways demonstrated that high glucose enhanced the LPS-induced microglial activation via the TLR4/JAK2/STAT3 pathway. Conclusion: This study demonstrates that high glucose, one of the key abnormalities characteristic of DM, can augment LPS-induced microglial activation and inflammatory cytokine levels through the TLR4/JAK2/STAT3 pathway, offering new insight into the pathophysiological relationship between DM and POCD.

  3. Transcriptional analysis of adaptation to high glucose concentrations in Zymomonas mobilis.

    Science.gov (United States)

    Zhang, Kun; Shao, Huanhuan; Cao, Qinghua; He, Ming-Xiong; Wu, Bo; Feng, Hong

    2015-02-01

    The ethanologenic bacterium Zymomonas mobilis is usually tolerant to high concentrations of glucose. The addition of sorbitol decreases the lag phase and increases ethanol yield and productivity of the bacteria in high glucose concentrations. The molecular mechanisms of adaptation to high glucose concentrations and the effect of sorbitol are still unclear. In this study, microarray analysis was used to study the global transcriptional adaptation responses of Z. mobilis to high glucose concentrations. A total of 235 genes were differentially expressed when 220 g/L glucose was added with or without 10 mM sorbitol. These genes are involved in diverse aspects of cell metabolism and regulation, including membrane transporters, nitrogen metabolism, and plasmid-encoded genes. However, most differentially expressed genes were downregulated when sorbitol was added. Notably, the transcription of almost all genes involved in the Entner-Doudoroff and ethanol production pathways was not significantly affected. In addition, a prophage and a nitrogen-fixation cluster were significantly induced. These results revealed that Z. mobilis cells responded to high glucose concentrations by regulating the transcriptional levels of genes related to membrane channels and transporters, stress response mechanisms, and metabolic pathways. These data provide insight into the intracellular adaptation responses to high glucose concentrations and reveal strategies to engineer efficient ethanol fermentation in Z. mobilis.

  4. High glucose induces podocyte injury via enhanced (prorenin receptor-Wnt-β-catenin-snail signaling pathway.

    Directory of Open Access Journals (Sweden)

    Caixia Li

    Full Text Available (Prorenin receptor (PRR expression is upregulated in diabetes. We hypothesized that PRR contributes to podocyte injury via activation of Wnt-β-catenin-snail signaling pathway. Mouse podocytes were cultured in normal (5 mM or high (25 mM D-glucose for 3 days. Compared to normal glucose, high glucose significantly decreased mRNA and protein expressions of podocin and nephrin, and increased mRNA and protein expressions of PRR, Wnt3a, β-catenin, and snail, respectively. Confocal microscopy studies showed significant reduction in expression and reorganization of podocyte cytoskeleton protein, F-actin, in response to high glucose. Transwell functional permeability studies demonstrated significant increase in albumin flux through podocytes monolayer with high glucose. Cells treated with high glucose and PRR siRNA demonstrated significantly attenuated mRNA and protein expressions of PRR, Wnt3a, β-catenin, and snail; enhanced expressions of podocin mRNA and protein, improved expression and reorganization of F-actin, and reduced transwell albumin flux. We conclude that high glucose induces podocyte injury via PRR-Wnt-β-catenin-snail signaling pathway.

  5. Hypoxia in high glucose followed by reoxygenation in normal glucose reduces the viability of cortical astrocytes through increased permeability of connexin 43 hemichannels

    Science.gov (United States)

    Orellana, Juan A.; Hernández, Diego E.; Ezan, Pascal; Velarde, Victoria; Bennett, Michael V. L.; Giaume, Christian; Sáez, Juan C.

    2009-01-01

    Brain ischemia causes more extensive injury in hyperglycemic than normoglycemic subjects, and the increased damage is to astroglia as well as neurons. In the present work, we found that in cortical astrocytes from rat or mouse, reoxygenation after hypoxia in a medium mimicking interstitial fluid during ischemia increases hemichannel activity and decreases cell-cell communication via gap junctions as indicated by dye uptake and dye coupling, respectively. These effects were potentiated by high glucose during the hypoxia in a concentration-dependent manner (and by zero glucose) and were not observed in connexin 43−/− astrocytes. The responses were transient or persistent after short and long periods of hypoxia, respectively. The persistent responses were associated with a progressive reduction in cell viability that was prevented by La3+ or peptides that block connexin 43 (Cx43) hemichannels or by inhibition of p38 MAP kinase prior to hypoxia-reoxygenation but not by treatments that block pannexin hemichannels. Block of Cx43 hemichannels did not affect the reduction in gap junction mediated dye coupling observed during reoxygenation. Cx43 hemichannels may be a novel therapeutic target to reduce cell death following stroke, particularly in hyperglycemic conditions. PMID:19705457

  6. Effects of adiponectin on oxidative stress and apoptosis in human cardiac myocytes cultured with high glucose

    Institute of Scientific and Technical Information of China (English)

    LI Xing; LI Mei-rong; GUO Zhi-xin

    2012-01-01

    Background Diabetic cardiomyopathy is the major cause of morbidity and mortality in diabetic patients.Oxidative stress plays an important role in diabetic cardiomyopathy.This study aimed to investigate the effects of adiponectin on oxidative stress and apoptosis in human cardiac myocytes (HCM) cultured with high glucose.Methods The cells were assigned to three group: control group,high glucose group and high glucose plus adiponectin group.After culture for 24,48,72 hours,oxidative stress was evaluated by detecting levels of malondialdehyde (MDA)and superoxide dismutase (SOD) in the supernatant of culture media.The expression of p66Shc and Heme oxygenase-1 (HO-1) was detected by real-time polymerase chain reaction (PCR).Flow cytometry was designed to observe and detect cellular apoptosis.Results Our findings showed significant increase in MDA levels and decrease in SOD activity in the high glucose group compared with the control group (P <0.05).However,MDA levels were significantly decreased and SOD activity was significantly increased in the adiponectin group compared with those in the high-glucose group (P <0.05).The mRNA expression of HO-1 in the high glucose group was significantly increased in a time-dependent manner compared with that in the control group (P <0.05).Adiponectin further increased the mRNA expression of HO-1 induced by high glucose in a time-dependent manner (P <0.05).The expression of p66Shc was significantly increased in high glucose group compared with that in the control group (P <0.05).Adiponectin significantly suppressed the upregulation of p66Shc induced by high glucose (P <0.05).The apoptotic rate of cardiomyocytes was significantly increased in the high glucose group compared with that in the control group while the apoptotic rate in the adiponectin group was remarkably declined in comparison with that in the high glucose group.Conclusion Adiponectin reduces high glucose-induced oxidative stress and apoptosis and plays a

  7. Prolonged exposure to resistin inhibits glucose uptake in rat skeletal muscles

    Institute of Scientific and Technical Information of China (English)

    Hong-qi FAN; Nan GU; Feng LIU; Li FEI; Xiao-qin PAN; Mei GUO; Rong-hua CHEN; Xi-rong GUO

    2007-01-01

    Aim: To assess the effects and mechanisms of the action of resistin on basal and insulin-stimulated glucose uptake in rat skeletal muscle cells. Methods: Rat myo-blasts (L6) were cultured and differentiated into myotubes followed by stimula-tion with single commercial resistin (130 ng/mL, 0-24 h) or cultured supernatant from 293-T cells transfected with resistin-expressing vectors (130 ng/mL, 0-24 h).Liquid scintillation counting was used to quantitate [3H] 2-deoxyglucose uptake.The transiocation of insulin-sensitive glucose transporters GLUT4 and GLUT1,synaptosomal-associated protein 23 (SNAP23) and GLUT protein content, as well as the tyrosine phosphorylation status and protein content of insulin receptor substrate (IRS) -1, were assessed by Western blotting. Results: Treatment of L6 myotubes with single resistin or cultured supernatant containing recombinant resistin reduced basal and insulin-stimulated 2-deoxyglucose uptake and impaired insulin-stimulated GLUT4 translocation. While SNAP23 protein content was decreased, no effects were noted in GLUT4 or GLUT1 protein content. Resistin also diminished insulin-stimulated IRS-1 tyrosine phosphorylation levels without affecting its protein content. The effects of recombinant resistin from 293-T cells transfected with resistin-expressing vectors were greater than that of single resistin treatment. Conclusion: Resistin regulated IRS-1 function and decreased GLUT4 translocation and glucose uptake in response to insulin. The downregulated expression of SNAP23 may have been partly attributed to the decrease of glucose uptake by resistin treatment. These observations highlight the potential role of resistin in the pathophysiology of type 2 diabetes related to obesity.

  8. Euglycemic Diabetic Ketoacidosis: A Potential Complication of Treatment With Sodium–Glucose Cotransporter 2 Inhibition

    OpenAIRE

    Peters, Anne L.; Buschur, Elizabeth O.; Buse, John B.; Cohan, Pejman; Diner, Jamie C.; Hirsch, Irl B.

    2015-01-01

    OBJECTIVE Sodium–glucose cotransporter 2 (SGLT-2) inhibitors are the most recently approved antihyperglycemic medications. We sought to describe their association with euglycemic diabetic ketoacidosis (euDKA) in hopes that it will enhance recognition of this potentially life-threatening complication. RESEARCH DESIGN AND METHODS Cases identified incidentally are described. RESULTS We identified 13 episodes of SGLT-2 inhibitor–associated euDKA or ketosis in nine individuals, seven with type 1 d...

  9. Highly sensitive glucose biosensor based on Au-Ni coaxial nanorod array having high aspect ratio.

    Science.gov (United States)

    Hsu, Che-Wei; Wang, Gou-Jen

    2014-06-15

    An effective glucose biosensor requires a sufficient amount of GOx immobilizing on the electrode surface. An electrode of a 3D nanorod array, having a larger surface-to-volume ratio than a 2D nanostructure, can accommodate more GOx molecules to immobilize onto the surface of the nanorods. In this study, a highly sensitive Au-Ni coaxial nanorod array electrode fabricated through the integration of nano electroforming and immersion gold (IG) method for glucose detection was developed. The average diameter of the as-synthesized Ni nanorods and that of the Au-Ni nanorods were estimated to be 150 and 250 nm, respectively; both had a height of 30 μm. The aspect ratio was 120. Compared to that of a flat Au electrode, the effective sensing area was enhanced by 79.8 folds. Actual glucose detections demonstrated that the proposed Au-Ni coaxial nanorod array electrode could operate in a linear range of 27.5 μM-27.5mM with a detection limit of 5.5μM and a very high sensitivity of 769.6 μA mM(-1)cm(-2). Good selectivity of the proposed sensing device was verified by sequential injections of uric acid (UA) and ascorbic acid (AA). Long-term stability was examined through successive detections over a period of 30 days.

  10. Performance of Fasting Plasma Glucose and Postprandial Urine Glucose in Screening for Diabetes in Chinese High-risk Population

    Institute of Scientific and Technical Information of China (English)

    Bing-Quan Yang; Yang Lu; Jia-Jia He; Tong-Zhi Wu; Zuo-Ling Xie; Cheng-Hao Lei; Yi Zhou

    2015-01-01

    Background: The conventional approaches to diabetes screening are potentially limited by poor compliance and laboratory demand.This study aimed to evaluate the performance of fasting plasma glucose (FPG) and postprandial urine glucose (PUG) in screening for diabetes in Chinese high-risk population.Methods: Nine hundred and nine subjects with high-risk factors of diabetes underwent oral glucose tolerance test after an overnight fast.FPG, hemoglobin A 1 c, 2-h plasma glucose (2 h-PG), and 2 h-PUG were evaluated.Diabetes and prediabetes were defined by the American Diabetes Association criteria.The area under the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy of 2 h-PUG, and the optimal cut-offdetermined to provide the largest Youden index.Spearman correlation was used for relationship analysis.Results: Among 909 subjects, 33.4% (304/909) of subjects had prediabetes, and 17.2% (156/909) had diabetes.The 2 h-PUG was positively related to FPG and 2 h-PG (r =0.428 and 0.551, respectively, both P < 0.001).For estimation of 2 h-PG ≥ 7.8 mmol/L and 2 h-PG ≥ 1 1.1 mmol/L using 2 h-PUG, the area under the ROC curve were 0.772 (95% confidence interval [CI]: 0.738-0.806) and 0.885 (95% CI:0.850~.921), respectively.The corresponding optimal cut-offs for 2 h-PUG were 5.6 mmol/L and 7.5 mmol/L, respectively.Compared with FPG alone, FPG combined with 2 h-PUG had a higher sensitivity for detecting glucose abnormalities (84.1% vs.73.7%, P < 0.001) and diabetes (82.7% vs.48.1%, P < 0.001).Conclusion: FPG combined with 2 h-PUG substantially improves the sensitivity in detecting prediabetes and diabetes relative to FPG alone, and may represent an efficient layperson-oriented diabetes screening method.

  11. Interferon regulatory factor-1 together with reactive oxygen species promotes the acceleration of cell cycle progression by up-regulating the cyclin E and CDK2 genes during high glucose-induced proliferation of vascular smooth muscle cells.

    Science.gov (United States)

    Zhang, Xi; Liu, Long; Chen, Chao; Chi, Ya-Li; Yang, Xiang-Qun; Xu, Yan; Li, Xiao-Tong; Guo, Shi-Lei; Xiong, Shao-Hu; Shen, Man-Ru; Sun, Yu; Zhang, Chuan-Sen; Hu, Kai-Meng

    2013-10-14

    The high glucose-induced proliferation of vascular smooth muscle cells (VSMCs) plays an important role in the development of diabetic vascular diseases. In a previous study, we confirmed that Interferon regulatory factor-1 (Irf-1) is a positive regulator of the high glucose-induced proliferation of VSMCs. However, the mechanisms remain to be determined. The levels of cyclin/CDK expression in two cell models involving Irf-1 knockdown and overexpression were quantified to explore the relationship between Irf-1 and its downstream effectors under normal or high glucose conditions. Subsequently, cells were treated with high glucose/NAC, normal glucose/H₂O₂, high glucose/U0126 or normal glucose/H₂O₂/U0126 during an incubation period. Then proliferation, cyclin/CDK expression and cell cycle distribution assays were performed to determine whether ROS/Erk1/2 signaling pathway was involved in the Irf-1-induced regulation of VSMC growth under high glucose conditions. We found that Irf-1 overexpression led to down-regulation of cyclin D1/CDK4 and inhibited cell cycle progression in VSMCs under normal glucose conditions. In high glucose conditions, Irf-1 overexpression led to an up-regulation of cyclin E/CDK2 and an acceleration of cell cycle progression, whereas silencing of Irf-1 suppressed the expression of both proteins and inhibited the cell cycle during the high glucose-induced proliferation of VSMCs. Treatment of VSMCs with antioxidants prevented the Irf-1 overexpression-induced proliferation of VSMCs, the up-regulation of cyclin E/CDK2 and the acceleration of cell cycle progression in high glucose conditions. In contrast, under normal glucose conditions, H₂O₂ stimulation and Irf-1 overexpression induced cell proliferation, up-regulated cyclin E/CDK2 expression and promoted cell cycle acceleration. In addition, overexpression of Irf-1 promoted the activation of Erk1/2 and when VSMCs overexpressing Irf-1 were treated with U0126, the specific Erk1/2 inhibitor

  12. Rhein reverses the diabetic phenotype of mesangial cells over-expressing the glucose transporter (GLUT1) by inhibiting the hexosamine pathway

    Science.gov (United States)

    Zheng, J-M; Zhu, J-M; Li, L-S; Liu, Z-H

    2008-01-01

    Background and purpose: Rhein, an anthraquinone compound isolated from rhubarb, has been proved effective in treatment of experimental diabetic nephropathy (DN). To explore the mechanism of its therapeutic effect on DN, rhein was tested for its effect on the hexosamine pathway. Experimental approach: The influence of rhein on cellular hypertrophy, fibronectin synthesis, glucose uptake, glutamine: fructose 6-phosphate aminotransferase (GFAT) activity, UDP-N-acetylglucosamine (UDP-GlcNAc) level and TGF-β1 and p21 expression was evaluated in MCGT1 cells, a GLUT1 transgenic rat mesangial cell line. GFAT activity in normal rat mesangial cells in high glucose concentrations and in vitro was also measured. Key results: Significantly increased fibronectin synthesis, cellular hypertrophy, much higher GFAT activity and UDP-GlcNAc level and increased TGF-β1 and p21 expression were found in MCGT1 cells cultured in normal glucose concentration. Rhein treatment decreased all these features of MCGT1 cells but did not exert a direct effect on GFAT enzymatic activity. Conclusions and implications: There was over-activity of the hexosamine pathway in MCGT1 cells, which may explain the higher expression of TGF-β1 and p21, the cellular hypertrophy and the increased expression of extracellular matrix (ECM) components in the cells. By inhibiting the increased activity the hexosamine pathway, rhein decreased TGF-β1 and p21 expression and thus contributed to the decreased cellular hypertrophy and ECM synthesis. Inhibition of the hexosamine pathway may be one of the mechanism through which rhein exerts its therapeutic role in diabetic nephropathy. PMID:18264122

  13. Astroglial pentose phosphate pathway rates in response to high-glucose environments

    Directory of Open Access Journals (Sweden)

    Norihiro Suzuki

    2012-03-01

    Full Text Available ROS (reactive oxygen species play an essential role in the pathophysiology of diabetes, stroke and neurodegenerative disorders. Hyperglycaemia associated with diabetes enhances ROS production and causes oxidative stress in vascular endothelial cells, but adverse effects of either acute or chronic high-glucose environments on brain parenchymal cells remain unclear. The PPP (pentose phosphate pathway and GSH participate in a major defence mechanism against ROS in brain, and we explored the role and regulation of the astroglial PPP in response to acute and chronic high-glucose environments. PPP activity was measured in cultured neurons and astroglia by determining the difference in rate of 14CO2 production from [1-14C]glucose and [6-14C]glucose. ROS production, mainly H2O2, and GSH were also assessed. Acutely elevated glucose concentrations in the culture media increased PPP activity and GSH level in astroglia, decreasing ROS production. Chronically elevated glucose environments also induced PPP activation. Immunohistochemical analyses revealed that chronic high-glucose environments induced ER (endoplasmic reticulum stress (presumably through increased hexosamine biosynthetic pathway flux. Nuclear translocation of Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2, which regulates G6PDH (glyceraldehyde-6-phosphate dehydrogenase by enhancing transcription, was also observed in association with BiP (immunoglobulin heavy-chain-binding protein expression. Acute and chronic high-glucose environments activated the PPP in astroglia, preventing ROS elevation. Therefore a rapid decrease in glucose level seems to enhance ROS toxicity, perhaps contributing to neural damage when insulin levels given to diabetic patients are not properly calibrated and plasma glucose levels are not adequately maintained. These findings may also explain the lack of evidence for clinical benefits from strict glycaemic control during the acute phase of stroke.

  14. Astroglial Pentose Phosphate Pathway Rates in Response to High-Glucose Environments

    Directory of Open Access Journals (Sweden)

    Shinichi Takahashi

    2012-02-01

    Full Text Available ROS (reactive oxygen species play an essential role in the pathophysiology of diabetes, stroke and neurodegenerative disorders. Hyperglycaemia associated with diabetes enhances ROS production and causes oxidative stress in vascular endothelial cells, but adverse effects of either acute or chronic high-glucose environments on brain parenchymal cells remain unclear. The PPP (pentose phosphate pathway and GSH participate in a major defence mechanism against ROS in brain, and we explored the role and regulation of the astroglial PPP in response to acute and chronic high-glucose environments. PPP activity was measured in cultured neurons and astroglia by determining the difference in rate of 14CO2 production from [1-14C]glucose and [6-14C]glucose. ROS production, mainly H2O2, and GSH were also assessed. Acutely elevated glucose concentrations in the culture media increased PPP activity and GSH level in astroglia, decreasing ROS production. Chronically elevated glucose environments also induced PPP activation. Immunohistochemical analyses revealed that chronic high-glucose environments induced ER (endoplasmic reticulum stress (presumably through increased hexosamine biosynthetic pathway flux. Nuclear translocation of Nrf2 (nuclear factor-erythroid 2 p45 subunit-related factor 2, which regulates G6PDH (glyceraldehyde-6-phosphate dehydrogenase by enhancing transcription, was also observed in association with BiP (immunoglobulin heavy-chain-binding protein expression. Acute and chronic high-glucose environments activated the PPP in astroglia, preventing ROS elevation. Therefore a rapid decrease in glucose level seems to enhance ROS toxicity, perhaps contributing to neural damage when insulin levels given to diabetic patients are not properly calibrated and plasma glucose levels are not adequately maintained. These findings may also explain the lack of evidence for clinical benefits from strict glycaemic control during the acute phase of stroke.

  15. Enhanced latent inhibition in high schizotypy individuals

    OpenAIRE

    Granger, Kiri T.; Moran, Paula M.; Buckley, Matthew G.; Haselgrove, Mark

    2016-01-01

    Latent inhibition refers to a retardation in learning about a stimulus that has been rendered familiar by non-reinforced preexposure, relative to a non-preexposed stimulus. Latent inhibition has been shown to be inversely correlated with schizotypy, and abnormal in people with schizophrenia, but these findings are inconsistent. One potential contributing factor to this inconsistency is that many tasks that purport to measure latent inhibition are confounded by alternative effects that also re...

  16. Synthetic peptide, Ala-Arg-Glu-Gly-Glu-Met, abolishes pro-proliferative and anti-apoptotic effects of high glucose in vascular smooth muscle cells.

    Science.gov (United States)

    Cao, Xiaozhou; Lyu, Yi; Ning, Junyu; Tang, Xiaozhi; Shen, Xinchun

    2017-02-11

    Apoptosis plays a critical role in normal vascular development and atherosclerosis. However, high glucose has been reported to generate a certain level of ROS that can inhibit vascular smooth muscle cell (VSMC) apoptosis, with the underlying mechanism remaining unclear. In this study, a synthetic peptide AREGEM (Ala-Arg-Glu-Gly-Glu-Met) exhibited antioxidative effects and was used to investigate its function in VSMCs during hyperglycaemia. MTT assay results demonstrated that AREGEM significantly attenuated high glucose-induced VSMCs proliferation. Flow cytometry displayed that high glucose levels inhibited cell apoptosis, whereas this effect was attenuated by pre-incubation with AREGEM. In addition, the 2',7'-dichlorofluorescein diacetate (DCFH-DA) fluorescent probe assay further demonstrated that AREGEM reduced intracellular ROS accumulation in VSMCs. Furthermore, this peptide was able to prevent the decrease of caspase-3 activity and the increase of the ratio of Bcl-2/Bax protein in VSMCs exposed to high glucose. These findings demonstrated that AREGEM is able to abolish the effects of high glucose in VSMCs; therefore, this peptide can be a potential candidate to develop a novel strategy for curing diabetic related diseases.

  17. High Glucose-Induced Oxidative Stress Mediates Apoptosis and Extracellular Matrix Metabolic Imbalances Possibly via p38 MAPK Activation in Rat Nucleus Pulposus Cells

    Directory of Open Access Journals (Sweden)

    Xiaofei Cheng

    2016-01-01

    Full Text Available Objectives. To investigate whether high glucose-induced oxidative stress is implicated in apoptosis of rat nucleus pulposus cells (NPCs and abnormal expression of critical genes involved in the metabolic balance of extracellular matrix (ECM. Methods. NPCs were cultured with various concentrations of glucose to detect cell viability and apoptosis. Cells cultured with high glucose (25 mM were untreated or pretreated with N-acetylcysteine or a p38 MAPK inhibitor SB 202190. Reactive oxygen species (ROS production was evaluated. Activation of p38 MAPK was measured by Western blot. The expression of ECM metabolism-related genes, including type II collagen, aggrecan, SRY-related high-mobility-group box 9 (Sox-9, matrix metalloproteinase 3 (MMP-3, and tissue inhibitor of metalloproteinase 1 (TIMP-1, was analyzed by semiquantitative RT-PCR. Results. High glucose reduced viability of NPCs and induced apoptosis. High glucose resulted in increased ROS generation and p38 MAPK activation. In addition, it negatively regulated the expression of type II collagen, aggrecan, Sox-9, and TIMP-1 and positively regulated MMP-3 expression. These results were changed by pretreatment with N-acetylcysteine or SB 202190. Conclusions. High glucose might promote apoptosis of NPCs, trigger ECM catabolic pathways, and inhibit its anabolic activities, possibly through a p38 MAPK-dependent oxidative stress mechanism.

  18. High rates of glucose utilization in the gas gland of Atlantic cod (Gadus morhua) are supported by GLUT1 and HK1b.

    Science.gov (United States)

    Clow, Kathy A; Short, Connie E; Hall, Jennifer R; Gendron, Robert L; Paradis, Hélène; Ralhan, Ankur; Driedzic, William R

    2016-09-01

    The gas gland of physoclistous fish utilizes glucose to generate lactic acid that leads to the off-loading of oxygen from haemoglobin. This study addresses characteristics of the first two steps in glucose utilization in the gas gland of Atlantic cod (Gadus morhua). Glucose metabolism by isolated gas gland cells was 12- and 170-fold higher, respectively, than that in heart and red blood cells (RBCs) as determined by the production of (3)H2O from [2-(3)H]glucose. In the gas gland, essentially all of the glucose consumed was converted to lactate. Glucose uptake in the gas gland shows a very high dependence upon facilitated transport as evidenced by saturation of uptake of 2-deoxyglucose at a low extracellular concentration and a requirement for high levels of cytochalasin B for uptake inhibition despite the high efficacy of this treatment in heart and RBCs. Glucose transport is via glucose transporter 1 (GLUT1), which is localized to the glandular cells. GLUT1 western blot analysis from whole-tissue lysates displayed a band with a relative molecular mass of 52 kDa, consistent with the deduced amino acid sequence. Levels of 52 kDa GLUT1 in the gas gland were 2.3- and 33-fold higher, respectively, than those in heart and RBCs, respectively. Glucose phosphorylation is catalysed by hexokinase Ib (HKIb), a paralogue that cannot bind to the outer mitochondrial membrane. Transcript levels of HKIb in the gas gland were 52- and 57-fold more abundant, respectively, than those in heart and RBCs. It appears that high levels of GLUT1 protein and an unusual isoform of HKI are both critical for the high rates of glycolysis in gas gland cells. © 2016. Published by The Company of Biologists Ltd.

  19. Impaired glucose tolerance in rats fed low-carbohydrate, high-fat diets.

    Science.gov (United States)

    Bielohuby, Maximilian; Sisley, Stephanie; Sandoval, Darleen; Herbach, Nadja; Zengin, Ayse; Fischereder, Michael; Menhofer, Dominik; Stoehr, Barbara J M; Stemmer, Kerstin; Wanke, Rüdiger; Tschöp, Matthias H; Seeley, Randy J; Bidlingmaier, Martin

    2013-11-01

    Moderate low-carbohydrate/high-fat (LC-HF) diets are widely used to induce weight loss in overweight subjects, whereas extreme ketogenic LC-HF diets are used to treat neurological disorders like pediatric epilepsy. Usage of LC-HF diets for improvement of glucose metabolism is highly controversial; some studies suggest that LC-HF diets ameliorate glucose tolerance, whereas other investigations could not identify positive effects of these diets or reported impaired insulin sensitivity. Here, we investigate the effects of LC-HF diets on glucose and insulin metabolism in a well-characterized animal model. Male rats were fed isoenergetic or hypocaloric amounts of standard control diet, a high-protein "Atkins-style" LC-HF diet, or a low-protein, ketogenic, LC-HF diet. Both LC-HF diets induced lower fasting glucose and insulin levels associated with lower pancreatic β-cell volumes. However, dynamic challenge tests (oral and intraperitoneal glucose tolerance tests, insulin-tolerance tests, and hyperinsulinemic euglycemic clamps) revealed that LC-HF pair-fed rats exhibited impaired glucose tolerance and impaired hepatic and peripheral tissue insulin sensitivity, the latter potentially being mediated by elevated intramyocellular lipids. Adjusting visceral fat mass in LC-HF groups to that of controls by reducing the intake of LC-HF diets to 80% of the pair-fed groups did not prevent glucose intolerance. Taken together, these data show that lack of dietary carbohydrates leads to glucose intolerance and insulin resistance in rats despite causing a reduction in fasting glucose and insulin concentrations. Our results argue against a beneficial effect of LC-HF diets on glucose and insulin metabolism, at least under physiological conditions. Therefore, use of LC-HF diets for weight loss or other therapeutic purposes should be balanced against potentially harmful metabolic side effects.

  20. Regulation of glucose metabolism via hepatic forkhead transcription factor 1 (FoxO1) by Morinda citrifolia (noni) in high-fat diet-induced obese mice.

    Science.gov (United States)

    Nerurkar, Pratibha V; Nishioka, Adrienne; Eck, Philip O; Johns, Lisa M; Volper, Esther; Nerurkar, Vivek R

    2012-07-01

    Renewed interest in alternative medicine among diabetic individuals prompted us to investigate anti-diabetic effects of Morinda citrifolia (noni) in high-fat diet (HFD)-fed mice. Type 2 diabetes is associated with increased glucose production due to the inability of insulin to suppress hepatic gluconeogenesis and promote glycolysis. Insulin inhibits gluconeogenesis by modulating transcription factors such as forkhead box O (FoxO1). Based on microarray analysis data, we tested the hypothesis that fermented noni fruit juice (fNJ) improves glucose metabolism via FoxO1 phosphorylation. C57BL/6 male mice were fed a HFD and fNJ for 12 weeks. Body weights and food intake were monitored daily. FoxO1 expression was analysed by real-time PCR and Western blotting. Specificity of fNJ-associated FoxO1 regulation of gluconeogenesis was confirmed by small interfering RNA (siRNA) studies using human hepatoma cells, HepG2. Supplementation with fNJ inhibited weight gain and improved glucose and insulin tolerance and fasting glucose in HFD-fed mice. Hypoglycaemic properties of fNJ were associated with the inhibition of hepatic FoxO1 mRNA expression, with a concomitant increase in FoxO1 phosphorylation and nuclear expulsion of the proteins. Gluconeogenic genes, phosphoenolpyruvate C kinase (PEPCK) and glucose-6-phosphatase (G6P), were significantly inhibited in mice fed a HFD+fNJ. HepG2 cells demonstrated more than 80 % inhibition of PEPCK and G6P mRNA expression in cells treated with FoxO1 siRNA and fNJ. These data suggest that fNJ improves glucose metabolism via FoxO1 regulation in HFD-fed mice.

  1. Effects of hydrogen sulfide on high glucose-induced glomerular podocyte injury in mice.

    Science.gov (United States)

    Liu, Ye; Zhao, Huichen; Qiang, Ye; Qian, Guanfang; Lu, Shengxia; Chen, Jicui; Wang, Xiangdong; Guan, Qingbo; Liu, Yuantao; Fu, Yuqin

    2015-01-01

    The aim of this study was to assess the effects of hydrogen sulfide on high glucose-induced mouse podocyte (MPC) injury and the underlying mechanisms. Mouse podocytes were randomly divided into 4 groups, including high glucose (HG), normal glucose (NG), normal glucose + DL-propargylglycine (PPG), and high glucose + NaHS (HG + NaHS) groups for treatment. Then, ZO-2, nephrin, β-catenin, and cystathionine γ-lyase (CSE) protein expression levels were determined by western blot. We found that high glucose significantly reduced nephrin, ZO-2, and CSE expression levels (P<0.05), and overtly elevated β-catenin amounts (P<0.05), in a time-dependent manner. Likewise, PPG at different concentrations in normal glucose resulted in significantly lower CSE, ZO-2, and nephrin levels (P<0.05), and increased β-catenin amounts (P<0.05). Interestingly, significantly increased ZO-2 and nephrin levels, and overtly reduced β-catenin amounts were observed in the HG + NaHS group compared with HG treated cells (P<0.01). Compared with NG treated cells, decreased ZO-2 and nephrin levels and higher β-catenin amounts were obtained in the HG + NaHS group. In conclusion,CSE downregulation contributes to hyperglycemia induced podocyte injury, which is alleviated by exogenous H2S possibly through ZO-2 upregulation and the subsequent suppression of Wnt/β-catenin pathway.

  2. RhoA/rho kinase signaling reduces connexin43 expression in high glucose-treated glomerular mesangial cells with zonula occludens-1 involvement

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Xi [Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Department of Pharmaceutical Engineering, Ocean College, Hainan University, Haikou 570228 (China); Chen, Cheng; Huang, Kaipeng; Wang, Shaogui; Hao, Jie; Huang, Junying [Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China); Huang, Heqing, E-mail: huangheq@mail.sysu.edu.cn [Laboratory of Pharmacology and Toxicology, School of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006 (China)

    2014-10-01

    RhoA/Rho kinase (ROCK) signaling has been suggested to be involved in diabetic nephropathy (DN) pathogenesis. Altered expression of connexin43 (Cx43) has been found in kidneys of diabetic animals. Both of them have been found to regulate nuclear factor kappa-B (NF-κB) activation in high glucose-treated glomerular mesangial cells (GMCs). The aim of this study was to investigate the relationship between RhoA/ROCK signaling and Cx43 in the DN pathogenesis. We found that upregulation of Cx43 expression inhibited NF-κB p65 nuclear translocation induced by RhoA/ROCK signaling in GMCs. Inhibition of RhoA/ROCK signaling attenuated the high glucose-induced decrease in Cx43. F-actin accumulation and an enhanced interaction between zonula occludens-1 (ZO-1) and Cx43 were observed in high glucose-treated GMCs. ZO-1 depletion or disruption of F-actin formation also inhibited the reduction in Cx43 protein levels induced by high glucose. In conclusion, activated RhoA/ROCK signaling induces Cx43 degradation in GMCs cultured in high glucose, depending on F-actin regulation. Increased F-actin induced by RhoA/ROCK signaling promotes the association between ZO-1 and Cx43, which possibly triggered Cx43 endocytosis, a mechanism of NF-κB activation in high glucose-treated GMCs. - Highlights: • RhoA/ROCK signaling induces Cx43 degradation in GMCs. • F-actin and ZO-1 have functions in the regulation of Cx43 by RhoA/ROCK signaling. • We reveal the relationship between RhoA/ROCK and Cx43 in the activation of NF-κB.

  3. Progression from impaired fasting glucose and impaired glucose tolerance to diabetes in a high-risk screening programme in general practice: the ADDITION Study, Denmark

    DEFF Research Database (Denmark)

    Rasmussen, Signe Sætre; Glümer, Charlotte; Sandbæk, Annelli

    2007-01-01

    in Primary Care]). METHODS: Persons aged 40-69 years were screened for type 2 diabetes based on a high-risk, stepwise strategy. At baseline, anthropometric measurements, blood samples and questionnaire data were collected. A total of 1,160 persons had IFG or IGT at baseline: 811 (70%) accepted re......-examination after 1 year. Glucose tolerance classification was based on the 1999 WHO definition. At follow-up, diabetes was based on one diabetic glucose value of fasting blood glucose or 2-h blood glucose. RESULTS: At baseline, 308 persons had IFG and 503 had IGT. The incidence of diabetes was 17.6 and 18.8 per...

  4. Notch pathway is involved in high glucose-induced apoptosis in podocytes via Bcl-2 and p53 pathways.

    Science.gov (United States)

    Gao, Feng; Yao, Min; Shi, Yonghong; Hao, Jun; Ren, Yunzhuo; Liu, Qingjuan; Wang, Xiaomeng; Duan, Huijun

    2013-05-01

    Recent studies have shown that Notch pathway plays a key role in the pathogenesis of diabetic nephropathy (DN), however, the exact mechanisms remain elusive. Here we demonstrated that high glucose (HG) upregulated Notch pathway in podocytes accompanied with the alteration of Bcl-2 and p53 pathways, subsequently leading to podocytes apoptosis. Inhibition of Notch pathway by chemical inhibitor or specific short hairpin RNA (shRNA) vector in podocytes prevented Bcl-2- and p53-dependent cell apoptosis. These findings suggest that Notch pathway mediates HG-induced podocytes apoptosis via Bcl-2 and p53 pathways.

  5. Effect of taurine on GFAP and TauT expressions in rat retinal Müller cells in high glucose culture

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ya-jie; XU Hong-xia; ZENG Kai-hong; MI Man-tian

    2007-01-01

    Objective:To detect the expression of glial fibrillary acid protein (GFAP) and taurine transporter (TauT) in the retinal Müller cells in high glucose culture with taurine and to explore the influence of glucose on the taurine transporting, and the possible protective effects of taurine on Müller cells in early diabetic retinopathy. Methods: The Müller cells from the rat retina were cultured in high glucose, and GFAP and TauT expressions were detected in the cells treated with different doses of taurine by immuocytochemical fluorescein staining and Western blotting. Results: High glucose enhanced the expression of GFAP and decreased the expression of TauT in Müller cells. Taurine decreased the up-regulation of GFAP in the cells which was induced by high glucose; 0. 1-10 mmol/L taurine increased the expression of TauT in Müller cells. Conclusion: Taurine can inhibit the changes in Müller cell resulted from high glucose.

  6. Anti-proliferative activity of oral anti-hyperglycemic agents on human vascular smooth muscle cells: thiazolidinediones (glitazones have enhanced activity under high glucose conditions

    Directory of Open Access Journals (Sweden)

    de Dios Stephanie T

    2007-10-01

    Full Text Available Abstract Background Inhibition of vascular smooth muscle cell (vSMC proliferation by oral anti-hyperglycemic agents may have a role to play in the amelioration of vascular disease in diabetes. Thiazolidinediones (TZDs inhibit vSMC proliferation but it has been reported that they anomalously stimulate [3H]-thymidine incorporation. We investigated three TZDs, two biguanides and two sulfonylureas for their ability of inhibit vSMC proliferation. People with diabetes obviously have fluctuating blood glucose levels thus we determined the effect of media glucose concentration on the inhibitory activity of TZDs in a vSMC preparation that grew considerably more rapidly under high glucose conditions. We further explored the mechanisms by which TZDs increase [3H]-thymidine incorporation. Methods VSMC proliferation was investigated by [3H]-thymidine incorporation into DNA and cell counting. Activation and inhibition of thymidine kinase utilized short term [3H]-thymidine uptake. Cell cycle events were analyzed by FACS. Results VSMC cells grown for 3 days in DMEM with 5% fetal calf serum under low (5 mM glucose and high (25 mM glucose increased in number by 2.5 and 4.7 fold, respectively. Rosiglitazone and pioglitazone showed modest but statistically significantly greater inhibitory activity under high versus low glucose conditions (P 3H]-thymidine into DNA but did not increase cell numbers. Troglitazone inhibited serum mediated thymidine kinase induction in a concentration dependent manner. FACS analysis showed that troglitazone and rosiglitazone but not pioglitazone placed a slightly higher percentage of cells in the S phase of a growing culture. Of the biguanides, metformin had no effect on proliferation assessed as [3H]-thymidine incorporation or cell numbers whereas phenformin was inhibitory in both assays albeit at high concentrations. The sulfonylureas chlorpropamide and gliclazide had no inhibitory effect on vSMC proliferation assessed by either [3H

  7. High molecular weight plant heteropolysaccharides stimulate fibroblasts but inhibit keratinocytes.

    Science.gov (United States)

    Shahbuddin, Munira; Shahbuddin, Dahlia; Bullock, Anthony J; Ibrahim, Halijah; Rimmer, Stephen; MacNeil, Sheila

    2013-06-28

    Konjac glucomannan (KGM) is a natural polysaccharide of β(1-4)-D-glucomannopyranosyl backbone of D-mannose and D-glucose derived from the tuber of Amorphophallus konjac C. Koch. KGM has been reported to have a wide range of activities including wound healing. In this study we examined KGM extracts prepared from five plant species, (Amorphophallus konjac Koch, Amorphophallus oncophyllus, Amorphophallus prainii, Amorphophallus paeoniifolius and Amorphophallus elegans) for their effects on cultured human keratinocytes and fibroblasts. Extracts from A. konjac Koch, A. oncophyllus and A. prainii (but not from A. paeoniifolius or A. elegans) stimulated fibroblast proliferation both in the absence and presence of serum. However, these materials inhibited keratinocyte proliferation. The fibroblast stimulatory activity was associated with high molecular weight fractions of KGM and was lost following ethanol extraction or enzyme digestion with β-mannanase. It was also reduced by the addition of concanavalin A but not mannose suggesting that these heteropolysaccharides are acting on lectins but not via receptors specific to mannose. The most dramatic effect of KGM was seen in its ability to support fibroblasts for 3weeks under conditions of deliberate media starvation. This effect did not extend to supporting keratinocytes under conditions of media starvation but KGM did significantly help support adipose derived stem cells under media starvation conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

  8. Downregulation of VEGF and upregulation of TL1A expression induce HUVEC apoptosis in response to high glucose stimuli.

    Science.gov (United States)

    Yu, Miao; Lu, Guihua; Zhu, Xun; Huang, Zhibin; Feng, Chong; Fang, Rong; Wang, Yesong; Gao, Xiuren

    2016-04-01

    High glucose‑induced endothelial cell apoptosis is considered to be the initiator of diabetes‑associated vascular complications. Experiments in vivo and in vitro have demonstrated that high glucose levels contribute to the apoptosis of endothelial cells by mediating cellular dysfunction and metabolic disorder via the production of various cytokines. As the most important endogenous vascular regulators, the balance between pro‑proliferative effector vascular endothelial growth factor (VEGF) and anti‑proliferative effector tumor necrosis factor‑like cytokine 1A (TL1A) is important in the modulation of endothelial cell survival and proliferation, and neovascularization. The present study aimed to explore whether the imbalance between VEGF and TL1A affected the apoptosis of human umbilical vein endothelial cells (HUVECs) exposed to high glucose conditions and then further investigated the potential mechanism. The results showed that the downregulation of VEGF in combination with the upregulation of TL1A in response to high glucose levels led to enhanced HUVEC apoptosis. Further experiments revealed that silencing high glucose‑induced TL1A expression using TL1A small interfering (si)RNA or the overexpression of VEGF by transfection with VEGF DNA resulted in a reduced HUVEC apoptosis rate compared with the controls. The effects occurred by attenuating and activating the phosphoinositide 3‑kinase/Akt/endothelial nitric oxide synthase pathway, respectively. In addition, VEGF and TL1A inhibited each other in hyperglycemia. In conclusion, these findings provide theoretical support for the further investigation of novel therapeutic strategies designed to maintain the balance between VEGF and TL1A and, thus, to prevent the onset and progression of endothelial cell apoptosis in response to high glucose stimuli.

  9. Personalized Metabolomics for Predicting Glucose Tolerance Changes in Sedentary Women After High-Intensity Interval Training

    OpenAIRE

    Kuehnbaum, Naomi L.; Gillen, Jenna B.; Gibala, Martin J.; Britz-McKibbin, Philip

    2014-01-01

    High-intensity interval training (HIIT) offers a practical approach for enhancing cardiorespiratory fitness, however its role in improving glucose regulation among sedentary yet normoglycemic women remains unclear. Herein, multi-segment injection capillary electrophoresis-mass spectrometry is used as a high-throughput platform in metabolomics to assess dynamic responses of overweight/obese women (BMI > 25, n = 11) to standardized oral glucose tolerance tests (OGTTs) performed before and after...

  10. Adult male northern elephant seals maintain high rates of glucose production during extended breeding fasts.

    Science.gov (United States)

    Crocker, Daniel E; Wenzel, Brian K; Champagne, Cory D; Houser, Dorian S

    2017-04-18

    Many species undergo natural fasts as part of their life histories. Extended fasting is associated with increased β-oxidation of fatty acids and reduced oxidation of glucose to minimize commitment of body protein to gluconeogenesis. However, the metabolic strategies used to sustain extended fasts simultaneous with high rates of energy expenditure are not well understood. Studies in fasting adult female and weanling northern elephant seals (NES) have revealed high rates of endogenous glucose production (EGP) under constraints of high nutrient demand for lactation or development but relatively low rates of metabolism. These studies revealed low rates of glucose oxidation and high rates of glucose recycling through the Cori cycle. We measured rates of glucose flux in fasting adult male NES to assess how significantly longer fasting durations, higher metabolic rates, and greater rates of muscular activity affect glucose kinetics. We measured glucose turnover in 18 adult males using the clearance of [6-H(3)] glucose during breeding and molting. Adult male NES maintain high rates of EGP across extended fasts. EGP greatly exceeded estimated needs for glucose-dependent tissues, varied directly with plasma insulin and lactate concentrations, and was inversely related to plasma ketoacid concentrations. Together, these findings suggest that high rates of glucose production and recycling during breeding maintain high blood glucose levels to support glucose-dependent tissues while minimizing production of ketoacids and commitment of protein stores to glucose production.

  11. Exposure to High Glucose Concentration Decreases Cell Surface ABCA1 and HDL Biogenesis in Hepatocytes.

    Science.gov (United States)

    Tsujita, Maki; Hossain, Mohammad Anwar; Lu, Rui; Tsuboi, Tomoe; Okumura-Noji, Kuniko; Yokoyama, Shinji

    2017-04-19

    To study atherosclerosis risk in diabetes, we investigated ATP-binding cassette transporter A1 (ABCA1) expression and high-density lipoprotein (HDL) biogenesis in the liver and hepatocytes under hyperglycemic conditions. In streptozotocin-induced diabetic mice, plasma HDL decreased while ABCA1 protein increased without changing its mRNA in the liver, only in the animals that responded to the treatment to show hypoinsulinemia and fasting hyperglycemia but not in the poor responders not showing those. To study the mechanism for this finding, hepatocytes were isolated from the control and diabetic mice, and they showed no difference in expression of ABCA1 protein, its mRNA, and HDL biogenesis in 1 g/l d-glucose but showed decreased HDL biogenesis in 4.5 g/l d-glucose although ABCA1 protein increased without change in its mRNA. Similar findings were confirmed in HepG2 cells with d-glucose but not with l-glucose. Thus, these cell models reproduced the in vivo findings in hyperglycemia. Labeling of cell surface protein revealed that surface ABCA1 decreased in high concentration of d-glucose in HepG2 cells despite the increase of cellular ABCA1 while not with l-glucose. Immunostaining of ABCA1 in HepG2 cells demonstrated the decrease of surface ABCA1 but increase of intracellular ABCA1 with high d-glucose. Clearance of ABCA1 was retarded both in primary hepatocytes and HepG2 cells exposed to high d-glucose but not to l-glucose, being consistent with the decrease of surface ABCA1. It is suggested that localization of ABCA1 to the cell surface is decreased in hepatocytes in hyperglycemic condition to cause decrease of HDL biogenesis.

  12. Oxygen glucose deprivation post-conditioning protects cortical neurons against oxygen-glucose deprivation injury: role of HSP70 and inhibition of apoptosis.

    Science.gov (United States)

    Zhao, Jian-hua; Meng, Xian-li; Zhang, Jian; Li, Yong-li; Li, Yue-juan; Fan, Zhe-ming

    2014-02-01

    In the present study, we examined the effect of oxygen glucose deprivation (OGD) post-conditioning (PostC) on neural cell apoptosis in OGD-PostC model and the protective effect on primary cortical neurons against OGD injury in vitro. Four-h OGD was induced by OGD by using a specialized and humidified chamber. To initiate OGD, culture medium was replaced with de-oxygenated and glucose-free extracellular solution-Locke's medium. After OGD treatment for 4 h, cells were then allowed to recover for 6 h or 20 h. Then lactate dehydrogenase (LDH) release assay, Western blotting and flow cytometry were used to detect cell death, protein levels and apoptotic cells, respectively. For the PostC treatment, three cycles of 15-min OGD, followed by 15 min normal cultivation, were applied immediately after injurious 4-h OGD. Cells were then allowed to recover for 6 h or 20 h, and cell death was assessed by LDH release assay. Apoptotic cells were flow cytometrically evaluated after 4-h OGD, followed by re-oxygenation for 20 h (O4/R20). In addition, Western blotting was used to examine the expression of heat-shock protein 70 (HSP70), Bcl-2 and Bax. The ratio of Bcl-2 expression was (0.44±0.08)% and (0.76±0.10)%, and that of Bax expression was (0.51±0.05)% and (0.39±0.04)%, and that of HSP70 was (0.42±0.031)% and (0.72±0.045)% respectively in OGD group and PostC group. After O4/R6, the rate of neuron death in PostC group and OGD groups was (28.96±3.03)% and (37.02±4.47)%, respectively. Therefore, the PostC treatment could up-regulate the expression of HSP70 and Bcl-2, but down-regulate Bax expression. As compared with OGD group, OGD-induced neuron death and apoptosis were significantly decreased in PostC group (P<0.05). These findings suggest that PostC inhibited OGD-induced neuron death. This neuro-protective effect is likely achieved by anti-apoptotic mechanisms and is associated with over-expression of HSP70.

  13. Glucose starvation-mediated inhibition of salinomycin induced autophagy amplifies cancer cell specific cell death.

    Science.gov (United States)

    Jangamreddy, Jaganmohan R; Jain, Mayur V; Hallbeck, Anna-Lotta; Roberg, Karin; Lotfi, Kourosh; Łos, Marek J

    2015-04-30

    Salinomycin has been used as treatment for malignant tumors in a small number of humans, causing far less side effects than standard chemotherapy. Several studies show that Salinomycin targets cancer-initiating cells (cancer stem cells, or CSC) resistant to conventional therapies. Numerous studies show that Salinomycin not only reduces tumor volume, but also decreases tumor recurrence when used as an adjuvant to standard treatments. In this study we show that starvation triggered different stress responses in cancer cells and primary normal cells, which further improved the preferential targeting of cancer cells by Salinomycin. Our in vitro studies further demonstrate that the combined use of 2-Fluoro 2-deoxy D-glucose, or 2-deoxy D-glucose with Salinomycin is lethal in cancer cells while the use of Oxamate does not improve cell death-inducing properties of Salinomycin. Furthermore, we show that treatment of cancer cells with Salinomycin under starvation conditions not only increases the apoptotic caspase activity, but also diminishes the protective autophagy normally triggered by the treatment with Salinomycin alone. Thus, this study underlines the potential use of Salinomycin as a cancer treatment, possibly in combination with short-term starvation or starvation-mimicking pharmacologic intervention.

  14. Euglycemic Diabetic Ketoacidosis: A Potential Complication of Treatment With Sodium–Glucose Cotransporter 2 Inhibition

    Science.gov (United States)

    Buschur, Elizabeth O.; Buse, John B.; Cohan, Pejman; Diner, Jamie C.; Hirsch, Irl B.

    2015-01-01

    OBJECTIVE Sodium–glucose cotransporter 2 (SGLT-2) inhibitors are the most recently approved antihyperglycemic medications. We sought to describe their association with euglycemic diabetic ketoacidosis (euDKA) in hopes that it will enhance recognition of this potentially life-threatening complication. RESEARCH DESIGN AND METHODS Cases identified incidentally are described. RESULTS We identified 13 episodes of SGLT-2 inhibitor–associated euDKA or ketosis in nine individuals, seven with type 1 diabetes and two with type 2 diabetes, from various practices across the U.S. The absence of significant hyperglycemia in these patients delayed recognition of the emergent nature of the problem by patients and providers. CONCLUSIONS SGLT-2 inhibitors seem to be associated with euglycemic DKA and ketosis, perhaps as a consequence of their noninsulin-dependent glucose clearance, hyperglucagonemia, and volume depletion. Patients with type 1 or type 2 diabetes who experience nausea, vomiting, or malaise or develop a metabolic acidosis in the setting of SGLT-2 inhibitor therapy should be promptly evaluated for the presence of urine and/or serum ketones. SGLT-2 inhibitors should only be used with great caution, extensive counseling, and close monitoring in the setting of type 1 diabetes. PMID:26078479

  15. The Na+ glucose co-transporter inhibitor canagliflozin activates AMP-activated protein kinase by inhibiting mitochondrial function and increasing cellular AMP levels

    OpenAIRE

    Hawley, Simon A.; Ford, Rebecca J.; Smith, Brennan K.; Gowans, Graeme J.; Mancini, Sarah; Pitt, Ryan D.; Day, Emily A.; Salt, Ian P.; Steinberg, Gregory R.; Hardie, D. Grahame

    2016-01-01

    Canagliflozin, dapagliflozin and empagliflozin, all recently approved for treatment of Type 2 diabetes, were derived from the natural product phlorizin. They reduce hyperglycemia by inhibiting glucose re-uptake by SGLT2 in the kidney, without affecting intestinal glucose uptake by SGLT1. We now report that canagliflozin also activates AMP-activated protein kinase (AMPK), an effect also seen with phloretin (the aglycone breakdown product of phlorizin), but not to any significant extent with da...

  16. High glucose alters retinal astrocytes phenotype through increased production of inflammatory cytokines and oxidative stress.

    Directory of Open Access Journals (Sweden)

    Eui Seok Shin

    Full Text Available Astrocytes are macroglial cells that have a crucial role in development of the retinal vasculature and maintenance of the blood-retina-barrier (BRB. Diabetes affects the physiology and function of retinal vascular cells including astrocytes (AC leading to breakdown of BRB. However, the detailed cellular mechanisms leading to retinal AC dysfunction under high glucose conditions remain unclear. Here we show that high glucose conditions did not induce the apoptosis of retinal AC, but instead increased their rate of DNA synthesis and adhesion to extracellular matrix proteins. These alterations were associated with changes in intracellular signaling pathways involved in cell survival, migration and proliferation. High glucose conditions also affected the expression of inflammatory cytokines in retinal AC, activated NF-κB, and prevented their network formation on Matrigel. In addition, we showed that the attenuation of retinal AC migration under high glucose conditions, and capillary morphogenesis of retinal endothelial cells on Matrigel, was mediated through increased oxidative stress. Antioxidant proteins including heme oxygenase-1 and peroxiredoxin-2 levels were also increased in retinal AC under high glucose conditions through nuclear localization of transcription factor nuclear factor-erythroid 2-related factor-2. Together our results demonstrated that high glucose conditions alter the function of retinal AC by increased production of inflammatory cytokines and oxidative stress with significant impact on their proliferation, adhesion, and migration.

  17. Fyn Mediates High Glucose-Induced Actin Cytoskeleton Reorganization of Podocytes via Promoting ROCK Activation In Vitro

    Directory of Open Access Journals (Sweden)

    Zhimei Lv

    2016-01-01

    Full Text Available Fyn, a member of the Src family of tyrosine kinases, is a key regulator in cytoskeletal remodeling in a variety of cell types. Recent studies have demonstrated that Fyn is responsible for nephrin tyrosine phosphorylation, which will result in polymerization of actin filaments and podocyte damage. Thus detailed involvement of Fyn in podocytes is to be elucidated. In this study, we investigated the potential role of Fyn/ROCK signaling and its interactions with paxillin. Our results presented that high glucose led to filamentous actin (F-actin rearrangement in podocytes, accompanied by paxillin phosphorylation and increased cell motility, during which Fyn and ROCK were markedly activated. Gene knockdown of Fyn by siRNA showed a reversal effect on high glucose-induced podocyte damage and ROCK activation; however, inhibition of ROCK had no significant effects on Fyn phosphorylation. These observations demonstrate that in vitro Fyn mediates high glucose-induced actin cytoskeleton remodeling of podocytes via promoting ROCK activation and paxillin phosphorylation.

  18. Diacylglycerol kinase δ phosphorylates phosphatidylcholine-specific phospholipase C-dependent, palmitic acid-containing diacylglycerol species in response to high glucose levels.

    Science.gov (United States)

    Sakai, Hiromichi; Kado, Sayaka; Taketomi, Akinobu; Sakane, Fumio

    2014-09-19

    Decreased expression of diacylglycerol (DG) kinase (DGK) δ in skeletal muscles is closely related to the pathogenesis of type 2 diabetes. To identify DG species that are phosphorylated by DGKδ in response to high glucose stimulation, we investigated high glucose-dependent changes in phosphatidic acid (PA) molecular species in mouse C2C12 myoblasts using a newly established liquid chromatography/MS method. We found that the suppression of DGKδ2 expression by DGKδ-specific siRNAs significantly inhibited glucose-dependent increases in 30:0-, 32:0-, and 34:0-PA and moderately attenuated 30:1-, 32:1-, and 34:1-PA. Moreover, overexpression of DGKδ2 also enhanced the production of these PA species. MS/MS analysis revealed that these PA species commonly contain palmitic acid (16:0). D609, an inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), significantly inhibited the glucose-stimulated production of the palmitic acid-containing PA species. Moreover, PC-PLC was co-immunoprecipitated with DGKδ2. These results strongly suggest that DGKδ preferably metabolizes palmitic acid-containing DG species supplied from the PC-PLC pathway, but not arachidonic acid (20:4)-containing DG species derived from the phosphatidylinositol turnover, in response to high glucose levels.

  19. Inhibiting notch activity in breast cancer stem cells by glucose functionalized nanoparticles carrying γ-secretase inhibitors

    OpenAIRE

    2016-01-01

    Cancer stem cells (CSCs) are a challenge in cancer treatment due to their therapy resistance. We demonstrated that enhanced Notch signaling in breast cancer promotes self-renewal of CSCs that display high glycolytic activity and aggressive hormone-independent tumor growth in vivo. We took advantage of the glycolytic phenotype and the dependence on Notch activity of the CSCs and designed nanoparticles to target the CSCs. Mesoporous silica nanoparticles were functionalized with glucose moieties...

  20. MiR-3202 – Promoted H5V Cell Apoptosis by Directly Targeting Fas Apoptotic Inhibitory Molecule 2 (FAIM2) in High Glucose Condition

    Science.gov (United States)

    Huang, Xiaozhong; Xie, Hui; Xue, Guanhua; Ye, Meng; Zhang, Lan

    2017-01-01

    Background Vascular complications are a major concern for patients with diabetes. Endothelial cells (ECs) play a key role in vascular function. MicroRNAs (miRNAs) have been shown to play an important role in mediating EC function; miRNAs are vulnerable to hyperglycemic conditions. Previous reports verified that Fas apoptotic inhibitory molecule 2 (FAIM2) can inhibit cell apoptosis through repressing the FAS-associated death domain protein (FADD) pathway. This current study was designed to explore the potential involvement of miR-3202 in the pathogenesis of ECs in high-glucose conditions. Material/Methods The aim of this study was to investigate the role of miR-3202 in regulating hyperglycemia-induced ECs by targeting FAIM2. The endothelial cell line H5V was cultured in a high-glucose condition to induce damage to FAIM2 expression in ECs; mimic and inhibition of miR-3202 were used to enhance and depress miR-3202’s function to explore its function on FAIM2. Results Our study showed that FAIM2 was inhibited by high-glucose conditions, and miRNA-3202 was induced by high-glucose conditions. FAIM2 was identified as the target gene of miRNA-3202; luciferase reporter assays confirmed that FAIM2 was downregulated by miR-3202 directly, that is, miR-3202 can upregulate Fas/FADD through inhibiting FAIM2. Conclusions MiR-3202 can promote EC apoptosis in hyperglycemic conditions, which demonstrated that EC apoptosis induced by high-glucose conditions partly depends on miR-3202 targeting FAIM2. PMID:28228635

  1. Hydrophobic motif site-phosphorylated protein kinase CβII between mTORC2 and Akt regulates high glucose-induced mesangial cell hypertrophy.

    Science.gov (United States)

    Das, Falguni; Ghosh-Choudhury, Nandini; Mariappan, Meenalakshmi M; Kasinath, Balakuntalam S; Choudhury, Goutam Ghosh

    2016-04-01

    PKCβII controls the pathologic features of diabetic nephropathy, including glomerular mesangial cell hypertrophy. PKCβII contains the COOH-terminal hydrophobic motif site Ser-660. Whether this hydrophobic motif phosphorylation contributes to high glucose-induced mesangial cell hypertrophy has not been determined. Here we show that, in mesangial cells, high glucose increased phosphorylation of PKCβII at Ser-660 in a phosphatidylinositol 3-kinase (PI3-kinase)-dependent manner. Using siRNAs to downregulate PKCβII, dominant negative PKCβII, and PKCβII hydrophobic motif phosphorylation-deficient mutant, we found that PKCβII regulates activation of mechanistic target of rapamycin complex 1 (mTORC1) and mesangial cell hypertrophy by high glucose. PKCβII via its phosphorylation at Ser-660 regulated phosphorylation of Akt at both catalytic loop and hydrophobic motif sites, resulting in phosphorylation and inactivation of its substrate PRAS40. Specific inhibition of mTORC2 increased mTORC1 activity and induced mesangial cell hypertrophy. In contrast, inhibition of mTORC2 decreased the phosphorylation of PKCβII and Akt, leading to inhibition of PRAS40 phosphorylation and mTORC1 activity and prevented mesangial cell hypertrophy in response to high glucose; expression of constitutively active Akt or mTORC1 restored mesangial cell hypertrophy. Moreover, constitutively active PKCβII reversed the inhibition of high glucose-stimulated Akt phosphorylation and mesangial cell hypertrophy induced by suppression of mTORC2. Finally, using renal cortexes from type 1 diabetic mice, we found that increased phosphorylation of PKCβII at Ser-660 was associated with enhanced Akt phosphorylation and mTORC1 activation. Collectively, our findings identify a signaling route connecting PI3-kinase to mTORC2 to phosphorylate PKCβII at the hydrophobic motif site necessary for Akt phosphorylation and mTORC1 activation, leading to mesangial cell hypertrophy.

  2. Glibenclamide Induces Collagen IV Catabolism in High Glucose-Stimulated Mesangial Cells

    Directory of Open Access Journals (Sweden)

    Liping Zhu

    2012-01-01

    Full Text Available We have shown the full prevention of mesangial expansion in insulin-deficient diabetic rats by treatment with clinically-relevant dosages of glibenclamide (Glib. Studies in mesangial cells (MCs also demonstrated reduction in the high glucose (HG-induced accumulation of collagens, proposing that this was due to increased catabolism. In the present study, we investigated the signaling pathways that may be implicated in Glib action. Rat primary MCs were exposed to HG for 8 weeks with or without Glib in therapeutic (0.01 μM or supratherapeutic (1.0 μM concentrations. We found that HG increased collagen IV protein accumulation and PAI-1 mRNA and protein expression, in association with decreased cAMP generating capacity and decreased PKA activity. Low Glib increased collagen IV mRNA but fully prevented collagen IV protein accumulation and PAI-1 overexpression while enhancing cAMP formation and PKA activity. MMP2 mRNA, protein expression and gelatinolytic activity were also enhanced. High Glib was, overall, ineffective. In conclusion, low dosage/concentration Glib prevents HG-induced collagen accumulation in MC by enhancing collagen catabolism in a cAMP-PKA-mediated PAI-1 inhibition.

  3. Temporal metabolomic responses of cultured HepG2 liver cells to high fructose and high glucose exposures

    Science.gov (United States)

    Meissen, John K.; Hirahatake, Kristin M.; Adams, Sean H.; Fiehn, Oliver

    2014-01-01

    High fructose consumption has been implicated with deleterious effects on human health, including hyperlipidemia elicited through de novo lipogenesis. However, more global effects of fructose on cellular metabolism have not been elucidated. In order to explore the metabolic impact of fructose-containing nutrients, we applied both GC-TOF and HILIC-QTOF mass spectrometry metabolomic strategies using extracts from cultured HepG2 cells exposed to fructose, glucose, or fructose + glucose. Cellular responses were analyzed in a time-dependent manner, incubated in media containing 5.5 mM glucose + 5.0 mM fructose in comparison to controls incubated in media containing either 5.5 mM glucose or 10.5 mM glucose. Mass spectrometry identified 156 unique known metabolites and a large number of unknown compounds, which revealed metabolite changes due to both utilization of fructose and high-carbohydrate loads independent of hexose structure. Fructose was shown to be partially converted to sorbitol, and generated higher levels of fructose-1-phosphate as a precursor for glycolytic intermediates. Differentially regulated ratios of 3-phosphoglycerate to serine pathway intermediates in high fructose media indicated a diversion of carbon backbones away from energy metabolism. Additionally, high fructose conditions changed levels of complex lipids toward phosphatidylethanolamines. Patterns of acylcarnitines in response to high hexose exposure (10.5 mM glucose or glucose/fructose combination) suggested a reduction in mitochondrial beta-oxidation. PMID:26190955

  4. Glucose administration inhibits the hepatic activation of gluconeogenesis promoted by insulin-induced hypoglycemia

    Directory of Open Access Journals (Sweden)

    Sharize Betoni Galende

    2009-08-01

    Full Text Available The activation of hepatic gluconeogenesis in male Wistar adult 6 h fasted rats during insulin-induced hypoglycemia (IIH was previously demonstrated. In this study, the effects of intraperitoneal (ip glucose (100 mg/kg on the activation of liver gluconeogenesis during IIH was investigated. Thus, 6 h fasted rats that received ip regular insulin (1 U/kg and 30 min later ip saline (Control group or glucose (Experimental group were compared. All the experiments were executed 60 min after insulin injection. The glycemia of Control and Experimental groups were not different (P > 0.05. To investigate gluconeogenesis, liver perfusion experiments were performed. The results demonstrated that excepting glycerol, livers from rats which received ip glucose showed lower (P Em estudo recente empregando ratos Wistar com 6 h de privação alimentar demonstramos que ocorre ativação da neoglicogênese hepática durante a hipoglicemia induzida por insulina (HII. Neste estudo, os efeitos da administração intraperitoneal (ip de glicose (100 mg/kg sobre a ativação da neoglicogênese hepática durante a HII foi investigada. Assim, ratos com 6 h de privação alimentar que receberam insulina regular ip (1 U/kg e 30 min depois salina (Grupo Controle ou glicose ip (Grupo Experimental foram comparados. Os experimentos foram executados 60 min após a injeção de insulina. A glicemia dos grupos Controle e Experimental não foi diferente (P > 0.05. Para investigar a neoglicogênese, realizouse experimentos de perfusão de fígado. Os resultados demonstraram, exceto para o glicerol, que fígados de ratos que receberam glicose ip (Grupo Experimental, apresentaram menor taxa (P < 0.05 de neoglicogênese a partir de L-alanina, Lglutamina, L-lactato ou L-alanina + L-glutamina + L-lactato + glicerol. Portanto, a ausência de recuperação da glicemia após administração de glicose foi mediada por inibição da neoglicogênese hepática.

  5. Frequency of diabetes, impaired fasting glucose, and glucose intolerance in high-risk groups identified by a FINDRISC survey in Puebla City, Mexico

    Directory of Open Access Journals (Sweden)

    Hirales-Tamez O

    2012-11-01

    Full Text Available Hector García-Alcalá, Christelle Nathalie Genestier-Tamborero, Omara Hirales-Tamez, Jorge Salinas-Palma, Elena Soto-VegaFaculty of Medicine, Universidad Popular Autónoma del Estado de Puebla, Puebla Pue, MexicoBackground: As a first step in the prevention of diabetes, the International Diabetes Federation recommends identification of persons at risk using the Finnish type 2 Diabetes Risk Assessment (FINDRISC survey. The frequency of diabetes mellitus, impaired fasting glucose, and glucose intolerance in high-risk groups identified by FINDRISC is unknown in our country. The aim of this study was to determine the frequency of diabetes mellitus, impaired fasting glucose, and glucose intolerance in higher-risk groups using a FINDRISC survey in an urban population.Methods: We used a television program to invite interested adults to fill out a survey at a television station. An oral glucose tolerance test was performed in all persons with a FINDRISC score ≥ 15 points (high-risk and very high-risk groups. Patients were classified as normal (fasting glucose < 100 mg/dL and 2-hour glucose < 140 mg/dL, or having impaired fasting glucose (fasting glucose 100–125 mg/dL and 2-hour glucose < 140 mg/dL, glucose intolerance (fasting glucose < 126 mg/dL and 2-hour glucose 140–199 mg/dL, and diabetes mellitus (fasting glucose ≥ 126 mg/dL or 2-hour glucose ≥ 200 mg/dL. We describe the frequency of each diagnostic category in this selected population according to gender and age.Results: A total of 186 patients had a score ≥ 15. The frequencies of diabetes mellitus, impaired fasting glucose, glucose intolerance, and normal glucose levels were 28.6%, 25.9%, 29.2%, and 16.2%, respectively. We found a higher frequency of diabetes mellitus and impaired fasting glucose in men than in women (33% versus 27% and 40% versus 21%, respectively and more glucose intolerance in women than in men (34% versus 16%, P < 0.05. Patients with diabetes mellitus (52.55 ± 9

  6. Transmutation of Personal Glucose Meters into Portable and Highly Sensitive Microbial Pathogen Detection Platform.

    Science.gov (United States)

    Wang, Zhenzhen; Chen, Zhaowei; Gao, Nan; Ren, Jinsong; Qu, Xiaogang

    2015-10-07

    Herein, for the first time, we presented a simple and general approach by using personal glucose meters (PGM) for portable and ultrasensitive detection of microbial pathogens. Upon addition of pathogenic bacteria, glucoamylase-quaternized magnetic nanoparticles (GA-QMNPS) conjugates were disrupted by the competitive multivalent interactions between bacteria and QMNPS, resulting in the release of GA. After magnetic separation, the free GA could catalyze the hydrolysis of amylose into glucose for quantitative readout by PGM. In such way, PGM was transmuted into a bacterial detection device and extremely low detection limits down to 20 cells mL(-1) was achieved. More importantly, QMNPS could inhibit the growth of the bacteria and destroy its cellular structure, which enabled bacteria detection and inhibition simultaneously. The simplicity, portability, sensitivity and low cost of presented work make it attractive for clinical applications. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Hydrothermal synthesis of NiWO4 crystals for high performance non-enzymatic glucose biosensors

    Science.gov (United States)

    Mani, Sivakumar; Vediyappan, Veeramani; Chen, Shen-Ming; Madhu, Rajesh; Pitchaimani, Veerakumar; Chang, Jia-Yaw; Liu, Shang-Bin

    2016-01-01

    A facile hydrothermal route for the synthesis of ordered NiWO4 nanocrystals, which show promising applications as high performance non-enzymatic glucose sensor is reported. The NiWO4-modified electrodes showed excellent sensitivity (269.6 μA mM−1 cm−2) and low detection limit (0.18 μM) for detection of glucose with desirable selectivity, stability, and tolerance to interference, rendering their prospective applications as cost-effective, enzyme-free glucose sensors. PMID:27087561

  8. A quantitative proteomic analysis of cellular responses to high glucose media in Chinese hamster ovary cells.

    Science.gov (United States)

    Liu, Zhenke; Dai, Shujia; Bones, Jonathan; Ray, Somak; Cha, Sangwon; Karger, Barry L; Li, Jingyi Jessica; Wilson, Lee; Hinckle, Greg; Rossomando, Anthony

    2015-01-01

    A goal in recombinant protein production using Chinese hamster ovary (CHO) cells is to achieve both high specific productivity and high cell density. Addition of glucose to the culture media is necessary to maintain both cell growth and viability. We varied the glucose concentration in the media from 5 to 16 g/L and found that although specific productivity of CHO-DG44 cells increased with the glucose level, the integrated viable cell density decreased. To examine the biological basis of these results, we conducted a discovery proteomic study of CHO-DG44 cells grown under batch conditions in normal (5 g/L) or high (15 g/L) glucose over 3, 6, and 9 days. Approximately 5,000 proteins were confidently identified against an mRNA-based CHO-DG44 specific proteome database, with 2,800 proteins quantified with at least two peptides. A self-organizing map algorithm was used to deconvolute temporal expression profiles of quantitated proteins. Functional analysis of altered proteins suggested that differences in growth between the two glucose levels resulted from changes in crosstalk between glucose metabolism, recombinant protein expression, and cell death, providing an overall picture of the responses to high glucose environment. The high glucose environment may enhance recombinant dihydrofolate reductase in CHO cells by up-regulating NCK1 and down-regulating PRKRA, and may lower integrated viable cell density by activating mitochondrial- and endoplasmic reticulum-mediated cell death pathways by up-regulating HtrA2 and calpains. These proteins are suggested as potential targets for bioengineering to enhance recombinant protein production.

  9. Inhibition of glucose-transporter 1 (GLUT-1) expression reversed Warburg effect in gastric cancer cell MKN45.

    Science.gov (United States)

    Zhang, Tian-Biao; Zhao, Ying; Tong, Zhao-Xue; Guan, Yi-Fu

    2015-01-01

    Glucose transporter-1 (GLUT-1) plays critical roles in cancer development and progression. Warburg effect (aerobic glycolysis) contributes greatly to tumorigenesis and could be targeted for tumor therapy. However, published data on the relationship between GLUT-1 and Warburg effect are scarce. In this study, gastric cancer cell, MKN45, was transfected with GLUT-1 shRNA using Lipofectamine 2000. Oxygen consumption, LDH activity, lactate production and cytoplasmic pyruvate were detected after MKN45 cells with GLUT-1 knockdown. In the last, hexokinase 1 (HK1), HK2, and pyruvate kinase M2 (PKM2) expression were detected by using western blot. In this study, we showed that inhibition of GLUT-1 expression reversed Warburg effect in MKN45 cells, and induced apoptosis.

  10. Inhibition of glucose- and fructose-mediated protein glycation by infusions and ethanolic extracts of ten culinary herbs and spices

    Institute of Scientific and Technical Information of China (English)

    Jugjeet Singh Ramkissoon; Mohamad Fawzi Mahomoodally; Anwar Hussein Subratty; Nessar Ahmed

    2016-01-01

    Objective: To investigate the inhibitory activity of ten culinary herbs and spices namely on glucose-mediated glycation (GMG) and fructose-mediated glycation (FMG) of bovine serum albumin. Methods: Fluorescence was used as an index of albumin glycation using glucose and fructose as substrates in the presence of infusions and ethanolic extracts of ten culinary herbs and spices. Antioxidant activity of the extracts was evaluated using reducing power, metal ion chelating and superoxide radical scavenging assays. Phytochemicals profile was analysed using 13 standard methods. Results: FMG was found to be significantly higher than GMG (95 and 84 AU, respectively; P 0.05) was found in the percentage glycation inhibitory activity of infusions compared to ethanolic extracts. The mean percentage inhibitory activity of the extracts for GMG (45.9%) and for FMG (45.1%) was not significantly different (P > 0.05). Qualitative phytochemical analysis showed the presence of alkaloids, fla-vonoids, tannins, terpenoids, anthraquinones, steroids, reducing sugars, proteins, phenols, saponins, phlobatannins, and cardiac glycosides. Conclusions: The higher rate of fluorescence generation by fructation suggests that glycation by fructose deserves much attention as a glycating agent. Data herein showed that the extracts inhibited GMG and FMG. Thus, these edible plants could be a natural source of antioxidants and anti-glycation agent for preventing advanced glycation end-products-mediated complications.

  11. Regulation of MDA-MB-231 cell proliferation by GSK-3β involves epigenetic modifications under high glucose conditions

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Chanchal; Kaur, Jasmine; Tikoo, Kulbhushan, E-mail: tikoo.k@gmail.com

    2014-05-15

    Hyperglycemia is a critical risk factor for development and progression of breast cancer. We have recently reported that high glucose induces phosphorylation of histone H3 at Ser 10 as well as de-phosphorylation of GSK-3β at Ser 9 in MDA-MB-231 cells. Here, we elucidate the mechanism underlying hyperglycemia-induced proliferation in MDA-MB-231 breast cancer cells. We provide evidence that hyperglycemia led to increased DNA methylation and DNMT1 expression in MDA-MB-231 cells. High glucose condition led to significant increase in the expression of PCNA, cyclin D1 and decrease in the expression of PTPN 12, p21 and PTEN. It also induced hypermethylation of DNA at the promoter region of PTPN 12, whereas hypomethylation at Vimentin and Snail. Silencing of GSK-3β by siRNA prevented histone H3 phosphorylation and reduced DNMT1 expression. We show that chromatin obtained after immunoprecipitation with phospho-histone H3 was hypermethylated under high glucose condition, which indicates a cross-talk between DNA methylation and histone H3 phosphorylation. ChIP-qPCR analysis revealed up-regulation of DNMT1 and metastatic genes viz. Vimentin, Snail and MMP-7 by phospho-histone H3, which were down-regulated upon GSK-3β silencing. To the best of our knowledge, this is the first report which shows that interplay between GSK-3β activation, histone H3 phosphorylation and DNA methylation directs proliferation of breast cancer cells. - Highlights: • High glucose induces phosphorylation of histone H3 and dephosphorylation of GSK-3β. • Moreover, hyperglycemia also leads to increased DNA methylation in MDA-MB-231 cells. • Inhibition of GSK-3β prevented histone H3 phosphorylation and reduced DNMT1 levels. • Interplay exists between GSK-3β, histone H3 phosphorylation and DNA methylation.

  12. Trace glucose and lipid metabolism in high androgen and high-fat diet induced polycystic ovary syndrome rats

    Directory of Open Access Journals (Sweden)

    Zhai Hua-Ling

    2012-01-01

    Full Text Available Abstract Background There is a high prevalence of diabetes mellitus (DM and dyslipidemia in women with polycystic ovary syndrome (PCOS. The purpose of this study was to investigate the role of different metabolic pathways in the development of diabetes mellitus in high-androgen female mice fed with a high-fat diet. Methods Female Sprague-Dawley rats were divided into 3 groups: the control group(C, n = 10; the andronate-treated group (Andronate, n = 10 (treated with andronate, 1 mg/100 g body weight/day for 8 weeks; and the andronate-treated and high-fat diet group (Andronate+HFD, n = 10. The rate of glucose appearance (Ra of glucose, gluconeogenesis (GNG, and the rate of glycerol appearance (Ra of glycerol were assessed with a stable isotope tracer. The serum sex hormone levels, insulin levels, glucose concentration, and the lipid profile were also measured. Results Compared with control group, both andronate-treated groups exhibited obesity with higher insulin concentrations (P P Conclusions Andronate with HFD rat model showed ovarian and metabolic features of PCOS, significant increase in glucose Ra, GNG, and lipid profiles, as well as normal blood glucose levels. Therefore, aberrant IR, increased glucose Ra, GNG, and lipid metabolism may represent the early-stage of glucose and lipid kinetics disorder, thereby might be used as potential early-stage treatment targets for PCOS.

  13. High activity enables life on a high-sugar diet: blood glucose regulation in nectar-feeding bats.

    Science.gov (United States)

    Kelm, Detlev H; Simon, Ralph; Kuhlow, Doreen; Voigt, Christian C; Ristow, Michael

    2011-12-01

    High blood glucose levels caused by excessive sugar consumption are detrimental to mammalian health and life expectancy. Despite consuming vast quantities of sugar-rich floral nectar, nectar-feeding bats are long-lived, provoking the question of how they regulate blood glucose. We investigated blood glucose levels in nectar-feeding bats (Glossophaga soricina) in experiments in which we varied the amount of dietary sugar or flight time. Blood glucose levels increased with the quantity of glucose ingested and exceeded 25 mmol l(-1) blood in resting bats, which is among the highest values ever recorded in mammals fed sugar quantities similar to their natural diet. During normal feeding, blood glucose values decreased with increasing flight time, but only fell to expected values when bats spent 75 per cent of their time airborne. Either nectar-feeding bats have evolved mechanisms to avoid negative health effects of hyperglycaemia, or high activity is key to balancing blood glucose levels during foraging. We suggest that the coevolutionary specialization of bats towards a nectar diet was supported by the high activity and elevated metabolic rates of these bats. High activity may have conferred benefits to the bats in terms of behavioural interactions and foraging success, and is simultaneously likely to have increased their efficiency as plant pollinators.

  14. Curcumin improves high glucose-induced INS-1 cell insulin resistance via activation of insulin signaling.

    Science.gov (United States)

    Song, Zhenfeng; Wang, Huan; Zhu, Lin; Han, Mingbao; Gao, Yuan; Du, Yu; Wen, Ying

    2015-02-01

    Curcumin is a yellow pigment isolated from Corcuma longan. This research investigates the improvement of curcumin on INS-1 cells with insulin resistance induced by high glucose. INS-1 cells were treated with high glucose (30 mmol L(-1)) for 48 h. Subsequently, the medium was replaced with curcumin for 24 h. Curcumin effectively increased insulin gene expression and glucose stimulated insulin secretion (GSIS) in a dose-dependent manner. Furthermore, the molecular mechanism of curcumin-induced insulin expression and secretion in high glucose-induced INS-1 cells was investigated in this study. Curcumin increased the expression of glucose transporter 2 (GLUT2) and phosphorylation of insulin receptor (IR), insulin receptor substrate-1 (IRS1), phosphatidylinositol-3-kinase (PI3K) and AKT in the INS-1 cells. Moreover, curcumin stimulation increased the expression of PDX-1 and GCK. This investigation suggests that curcumin prevented high glucose-reduced insulin expression and secretion through activation of the PI3K/Akt/GLUT2 pathway in INS-1 cells.

  15. Changes and significance of SIRT3 expression in cellular senescence induced by high glucose

    Directory of Open Access Journals (Sweden)

    Bin ZHANG

    2011-09-01

    Full Text Available Objective To investigate the role of the silent information regulator 3(SIRT3 in the decrepitude process of human diploid fibroblasts(WI-38 induced by high glucose.Methods The WI-38 cells [population doublings(PDs,20-32] were cultured in media containing different concentrations of glucose as follows: low glucose(3.34mmol/L,LG,normal glucose(5.56mmol/L,NG,and high glucose(25mmol/L,HG.The protein expression levels of p21,p27,catalase,MnSOD,and SIRT3 were evaluated through Western blot.The double-label immunofluorescence assay was used to detect the location and expression of SIRT3,MnSOD,and senescence-associated heterochromatin foci(SAHF in the WI-38 cells.The ROS level was determined with fluorescent probe.Results The results from the Western blot showed that the protein expression of SIRT3,catalase,and MnSOD decreased significantly in the HG group compared with the LG and NG groups(P 0.05.SIRT3 and MnSOD were highly expressed in the cytoplasm.The ROS levels in the HG group were elevated compared with those in the LG and NG groups.Conclusion SIRT3 may play an important role in cellular senescence induced by high glucose in human diploid fibroblasts.

  16. Morroniside protects cultured human umbilical vein endothelial cells from damage by high ambient glucose

    Institute of Scientific and Technical Information of China (English)

    Hui-qin XU; Hai-ping HAO; Xu ZHANG; Yang PAN

    2004-01-01

    AIM: To determine whether morroniside, a compound in Comus officinalis Sieb et Zucc can prevent cultured human umbilical vein endothelial cells (HUVEC) from damage by high ambient glucose. METHODS: HUVEC was incubated in glucose, 5 or 30 mmol/L, either alone or in the presence of morroniside (final concentration 100, 10,and 1 μmol/L, respectively) for 48 h. The proliferation of HUVEC was quantified by MTT method; its cycle was analyzed by flow cytometry; morphological change was observed with fluorescence microscopy. RESULTS:Survival of HUVEC cultured in high ambient glucose was significantly decreased when compared to that in normal concentration of glucose (P<0.01). High ambient glucose also lowered the rate of cells entering into S-phase, along with severe morphological damage. With the intervention of morroniside (final concentration 100 and 10 μmol/L),the cell survival was significantly recovered (P<0.01, P<0.05, respectively), accompanied with increased S-phase rate and less extent of morphological damage. CONCLUSION: Morroniside protected HUVEC against high ambient glucose induced injury, which suggested that morroniside could exert a beneficial effect on preventing diabetic angiopathies.

  17. Inhibition of Small Maf Function in Pancreatic β-Cells Improves Glucose Tolerance Through the Enhancement of Insulin Gene Transcription and Insulin Secretion

    Science.gov (United States)

    Nomoto, Hiroshi; Miyoshi, Hideaki; Nakamura, Akinobu; Hida, Yoko; Yamashita, Ken-ichiro; Sharma, Arun J.; Atsumi, Tatsuya

    2015-01-01

    The large-Maf transcription factor v-maf musculoaponeurotic fibrosarcoma oncogene homolog A (MafA) has been found to be crucial for insulin transcription and synthesis and for pancreatic β-cell function and maturation. However, insights about the effects of small Maf factors on β-cells are limited. Our goal was to elucidate the function of small-Maf factors on β-cells using an animal model of endogenous small-Maf dysfunction. Transgenic (Tg) mice with β-cell-specific expression of dominant-negative MafK (DN-MafK) experiments, which can suppress the function of all endogenous small-Mafs, were fed a high-fat diet, and their in vivo phenotypes were evaluated. Phenotypic analysis, glucose tolerance tests, morphologic examination of β-cells, and islet experiments were performed. DN-MafK-expressed MIN6 cells were also used for in vitro analysis. The results showed that DN-MafK expression inhibited endogenous small-Maf binding to insulin promoter while increasing MafA binding. DN-MafK Tg mice under high-fat diet conditions showed improved glucose metabolism compared with control mice via incremental insulin secretion, without causing changes in insulin sensitivity or MafA expression. Moreover, up-regulation of insulin and glucokinase gene expression was observed both in vivo and in vitro under DN-MafK expression. We concluded that endogenous small-Maf factors negatively regulates β-cell function by competing for MafA binding, and thus, the inhibition of small-Maf activity can improve β-cell function. PMID:25763640

  18. Continuous glucose monitoring system and new era of early diagnosis of diabetes in high risk groups

    Directory of Open Access Journals (Sweden)

    Ashraf Soliman

    2014-01-01

    Full Text Available Continuous glucose monitoring (CGM systems are an emerging technology that allows frequent glucose measurements to monitor glucose trends in real time. Their use as a diagnostic tool is still developing and appears to be promising. Combining intermittent glucose self-monitoring (SGM and CGM combines the benefits of both. Significant improvement in the treatment modalities that may prevent the progress of prediabetes to diabetes have been achieved recently and dictates screening of high risk patients for early diagnosis and management of glycemic abnormalities. The use of CGMS in the diagnosis of early dysglycemia (prediabetes especially in high risk patients appears to be an attractive approach. In this review we searched the literature to investigate the value of using CGMS as a diagnostic tool compared to other known tools, namely oral glucose tolerance test (OGTT and measurement of glycated hemoglobin (HbA1C in high risk groups. Those categories of patients include adolescents and adults with obesity especially those with family history of type 2 diabetes mellitus, polycystic ovary syndrome (PCO, gestational diabetes, cystic fibrosis, thalassemia major, acute coronary syndrome (ACS, and after renal transplantation. It appears that the ability of the CGMS for frequently monitoring (every 5 min glucose changes during real-life settings for 3 to 5 days stretches the chance to detect more glycemic abnormalities during basal and postprandial conditions compared to other short-timed methods.

  19. Doped graphene/Cu nanocomposite: A high sensitivity non-enzymatic glucose sensor for food.

    Science.gov (United States)

    Shabnam, Luba; Faisal, Shaikh Nayeem; Roy, Anup Kumar; Haque, Enamul; Minett, Andrew I; Gomes, Vincent G

    2017-04-15

    An amperometric non-enzymatic glucose sensor was developed based on nitrogen-doped graphene with dispersed copper nanoparticles (Cu-NGr). The sensing element was tested in conjunction with a modified glassy carbon electrode for glucose detection. The Cu-NGr composite was prepared by one pot synthesis from a mixture of graphene oxide, copper nitrate and uric acid, followed by thermal annealing at 900°C for 1h. Detailed characterizations showed homogeneous copper nanoparticle dispersion and the presence of significant proportion of graphitic nitrogen. The developed electrode presented high electrocatalytic activity towards glucose through synergetic effect of copper nanoparticles and nitrogen-doped graphene. Amperometric analysis confirmed high glucose sensitivity and ultra-low detection of 10nM glucose over a linear range. The sensor was tested for direct application to detect glucose in food samples for which the sensor displayed high selectivity with excellent reproducibility and recovery in complex food materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Protective effect of telmisartan against oxidative damage induced by high glucose in neuronal PC12 cell.

    Science.gov (United States)

    Eslami, Habib; Sharifi, Ali M; Rahimi, Hamzeh; Rahati, Maryam

    2014-01-13

    Telmisartan is an angiotensin II type 1 receptor blocker and partial agonist of peroxisome proliferator-activated receptor gamma (PPAR-γ). Here, we investigated the protective capacity of telmisartan against high glucose (HG)-elicited oxidative damage in PC12 cells. The activity of lactate dehydrogenase (LDH), NADPH oxidase (NOX), superoxide dismutase (SOD), catalase (CAT) as well as the levels of malondialdehyde (MDA), glutathione (GSH), intracellular reactive oxygen species (ROS), cell viability and DNA fragmentation were measured in HG-treated PC12 cells with and without telmisartan co-treatment. Moreover, the direct antioxidant effect of telmisartan was determined by 2,2-azinobis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) assay and protein expression of Bax, Bcl-2, cleaved caspase-3 and NOX subunit p47phox by western blotting. Telmisartan exhibited antioxidant activity in the ABTS assay with the IC50 value of 37.5 μM. Pretreatment of PC12 cells with telmisartan, prior to HG exposure, was associated with a marked diminution in cleaved caspase-3 expression, DNA fragmentation, Bax/Bcl-2 ratio, intracellular ROS and MDA levels. Additionally, the cell viability, GSH level, SOD and CAT activity were notably elevated by telmisartan, whereas the activity and the protein expression of NADPH oxidase subunit p47phox were attenuated. Interestingly, co-treatment with GW9662, a PPAR-γ antagonist, partially inhibited the beneficial effects of telmisartan. These findings suggest that telmisartan has protective effects on HG-induced neurotoxicity in PC12 cells, which may be related to its antioxidant action and inhibition of NADPH oxidase. Furthermore, the results show that PPAR-γ activation is involved in the neuroprotective effects of telmisartan. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  1. USF-1 inhibition protects against oxygen-and-glucose-deprivation-induced apoptosis via the downregulation of miR-132 in HepG2 cells.

    Science.gov (United States)

    Wang, Renjie; Liang, Haiqian; Li, Hui; Dou, Herong; Zhang, Minghua; Baobuhe; Du, Zhenhua; Gao, Mojie; Wang, Ruimin

    2014-04-18

    Upstream stimulatory factor 1 (USF-1) is an important transcription factor that participates in glucose metabolism and tumorigenesis. The aim of the current study was to explore the regulatory mechanism of USF-1 in HepG2 cells exposed to oxygen and glucose deprivation (OGD). After the establishment of the OGD model in HepG2 cells, we determined that the cells treated with OGD exhibited a high apoptotic rate and that the introduction of siRNA against USF-1 protected the cells from OGD-induced apoptosis. The miRNA microarray results demonstrated that a set of miRNAs were deregulated in the cells transfected with USF-1 siRNA, and the set of downregulated miRNAs included a novel miRNA, miR-132. Further analyses indicated that miR-132 overexpression inhibits the protective roles of USF-1 siRNA in OGD-induced apoptosis. We also identified several binding sites for USF-1 in the miR-132 promoter. The silencing of USF-1 resulted in a reduction in miR-132 expression, and USF-1 overexpression increased the expression of this miRNA. Our study indicated that the silencing of USF-1 plays protective roles in OGD-induced apoptosis through the downregulation of miR-132, which indicates that the silencing of USF-1 may be a therapeutic strategy for the promotion of cancer cell survival under OGD conditions.

  2. Fear inhibition in high trait anxiety

    NARCIS (Netherlands)

    Kindt, M.; Soeter, M.

    2014-01-01

    Trait anxiety is recognized as an individual risk factor for the development of anxiety disorders but the neurobiological mechanisms remain unknown. Here we test whether trait anxiety is associated with impaired fear inhibition utilizing the AX+/BX- conditional discrimination procedure that allows f

  3. Metformin inhibition of mTORC1 activation, DNA synthesis and proliferation in pancreatic cancer cells: Dependence on glucose concentration and role of AMPK

    Energy Technology Data Exchange (ETDEWEB)

    Sinnett-Smith, James; Kisfalvi, Krisztina; Kui, Robert [Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA (United States); Rozengurt, Enrique, E-mail: erozengurt@mednet.ucla.edu [Division of Digestive Diseases, Department of Medicine, CURE: Digestive Diseases Research Center, David Geffen School of Medicine and Molecular Biology Institute, University of California at Los Angeles, CA (United States)

    2013-01-04

    Highlights: Black-Right-Pointing-Pointer Metformin inhibits cancer cell growth but the mechanism(s) are not understood. Black-Right-Pointing-Pointer We show that the potency of metformin is sharply dependent on glucose in the medium. Black-Right-Pointing-Pointer AMPK activation was enhanced in cancer cells incubated in physiological glucose. Black-Right-Pointing-Pointer Reciprocally, metformin potently inhibited mTORC1, DNA synthesis and proliferation. Black-Right-Pointing-Pointer Metformin, at low concentrations, inhibited DNA synthesis through AMPK. -- Abstract: Metformin, a widely used anti-diabetic drug, is emerging as a potential anticancer agent but the mechanisms involved remain incompletely understood. Here, we demonstrate that the potency of metformin induced AMPK activation, as shown by the phosphorylation of its substrates acetyl-CoA carboxylase (ACC) at Ser{sup 79} and Raptor at Ser{sup 792}, was dramatically enhanced in human pancreatic ductal adenocarcinoma (PDAC) cells PANC-1 and MiaPaCa-2 cultured in medium containing physiological concentrations of glucose (5 mM), as compared with parallel cultures in medium with glucose at 25 mM. In physiological glucose, metformin inhibited mTORC1 activation, DNA synthesis and proliferation of PDAC cells stimulated by crosstalk between G protein-coupled receptors and insulin/IGF signaling systems, at concentrations (0.05-0.1 mM) that were 10-100-fold lower than those used in most previous reports. Using siRNA-mediated knockdown of the {alpha}{sub 1} and {alpha}{sub 2} catalytic subunits of AMPK, we demonstrated that metformin, at low concentrations, inhibited DNA synthesis through an AMPK-dependent mechanism. Our results emphasize the importance of using medium containing physiological concentrations of glucose to elucidate the anticancer mechanism of action of metformin in pancreatic cancer cells and other cancer cell types.

  4. Release Profile and Inhibition Test of The Nanoparticles A. Paniculata Extract as Inhibitor of α-Glucosidase in The Process of Carbohydrates Breakdown Into Glucose Diabetes Mellitus

    Science.gov (United States)

    Imansari, Farisa; Sahlan, Muhammad; Arbianti, Rita

    2017-07-01

    Andrographis paniculata (A.paniculata) contain the main active substances Andrographolide which helps lower glucose levels in diabetics by inhibiting the enzyme α-glucosidase. The ability of the extract A.paniculata in lowering glucose levels will increase with the technique encapsulation with a coating of composition Chitosan-STPP as a drug delivery to the target organ. This study aimed to get an overview of A.paniculata release profile of nanoparticles in a synthetic fluid media with various concentrations of coating and inhibition testing nasty shard extract in inhibiting the enzyme α-glucosidase. This research resulted in nanoparticles by coating efficiency and loading capacity of chitosan greatest variation of 2% and 1% STPP 60% and 46.29%. chitosan greatest variation of 2% and 1% STPP 60% and 46.29%. The ability of A.paniculata extracts as α-glucosidase enzyme inhibitors has been demonstrated in this study, the percent inhibition of 33.17%.

  5. Phenotypic and gene expression changes between low (glucose-responsive) and High (glucose non-responsive) MIN-6 beta cells

    DEFF Research Database (Denmark)

    O´Driscoll, L.; Gammell, p.; McKierman, E.

    2006-01-01

    that the glucose-stimulated insulin secretion (GSIS) phenotype is relatively unstable, in long-term culture. This study aimed to investigate phenotypic and gene expression changes associated with this loss of GSIS, using the MIN-6 cell line as model. Phenotypic differences between MIN-6(L, low passage) and MIN-6(H......, high passage) were determined by ELISA (assessing GSIS and cellular (pro)insulin content), proliferation assays, phase contrast light microscopy and analysis of alkaline phosphatase expression. Differential mRNA expression was investigated using microarray, bioinformatics and real-time PCR technologies....... Long-term culture was found to be associated with many phenotypic changes, including changes in growth rate and cellular morphology, as well as loss of GSIS. Microarray analyses indicate expression of many mRNAs, including many involved in regulated secretion, adhesion and proliferation...

  6. Heritable transmission of stress resistance by high dietary glucose in Caenorhabditis elegans.

    Science.gov (United States)

    Tauffenberger, Arnaud; Parker, J Alex

    2014-05-01

    Glucose is a major energy source and is a key regulator of metabolism but excessive dietary glucose is linked to several disorders including type 2 diabetes, obesity and cardiac dysfunction. Dietary intake greatly influences organismal survival but whether the effects of nutritional status are transmitted to the offspring is an unresolved question. Here we show that exposing Caenorhabditis elegans to high glucose concentrations in the parental generation leads to opposing negative effects on fecundity, while having protective effects against cellular stress in the descendent progeny. The transgenerational inheritance of glucose-mediated phenotypes is dependent on the insulin/IGF-like signalling pathway and components of the histone H3 lysine 4 trimethylase complex are essential for transmission of inherited phenotypes. Thus dietary over-consumption phenotypes are heritable with profound effects on the health and survival of descendants.

  7. High reproducibility and sensitivity of bifacial copper nanowire array for detection of glucose

    Directory of Open Access Journals (Sweden)

    Hanqing Zhang

    2017-06-01

    Full Text Available The ordered bifacial copper nanowire array (Cu BNWA was synthesized by a template assisted electrochemical deposition method. The morphology and structure of the as-prepared samples were investigated by field emission scanning electron microscope (FESEM and X-ray diffraction (XRD. The results show that the ordered Cu nanowire array with uniform geometrical dimensions covered both side of the Cu substrate. When used as the electrode for glucose detection, the minimum detectable concentration of glucose can be reached as low as 0.2 mM. Impressively, the sample still showed high sensitivity and stability for glucose detection after two months placement in ambient environment. These excellent performances of the Cu BNWA make it a promising non-enzyme glucose detection sensor for various applications.

  8. Inhibition of biofilms by glucose oxidase, lactoperoxidase and guaiacol: the active antibacterial component in an enzyme alginogel.

    Science.gov (United States)

    Cooper, Rose A

    2013-12-01

    The association of biofilms with wound chronicity has prompted a search for antimicrobial interventions that are effective against biofilms. A patented preparation of glucose oxidase, lactoperoxidase and guaiacol (GLG), which is the antibacterial component of Flaminal, has been shown to inhibit a wide range of bacteria, but it has not yet been tested on biofilms. This study aims to determine the effect of GLG on biofilms of Staphylococcus aureus, methicillin-resistant S. aureus and Pseudomonas aeruginosa. Static biofilms were grown in microtitre plates and on coverslips and treated with a range of concentrations of GLG. Effects were monitored by estimating biofilm biomass by staining with crystal violet, biofilm activity by staining with either resazurin or fluorescein diacetate and biofilm viability by staining with LIVE/DEAD BacLight Bacterial Viability Kit. GLG was able to prevent the formation of biofilms at concentration ≤0.5% (w/v) and higher concentrations were required to inhibit established biofilms. GLG did not disrupt biofilm biomass. Staphylococci were more susceptible to GLG than P. aeruginosa. These in vitro findings must be verified by in vivo studies.

  9. Cofilin Inhibition Restores Neuronal Cell Death in Oxygen-Glucose Deprivation Model of Ischemia.

    Science.gov (United States)

    Madineni, Anusha; Alhadidi, Qasim; Shah, Zahoor A

    2016-03-01

    Ischemia is a condition associated with decreased blood supply to the brain, eventually leading to death of neurons. It is associated with a diverse cascade of responses involving both degenerative and regenerative mechanisms. At the cellular level, the changes are initiated prominently in the neuronal cytoskeleton. Cofilin, a cytoskeletal actin severing protein, is known to be involved in the early stages of apoptotic cell death. Evidence supports its intervention in the progression of disease states like Alzheimer's and ischemic kidney disease. In the present study, we have hypothesized the possible involvement of cofilin in ischemia. Using PC12 cells and mouse primary cultures of cortical neurons, we investigated the potential role of cofilin in ischemia in two different in vitro ischemic models: chemical induced oxidative stress and oxygen-glucose deprivation/reperfusion (OGD/R). The expression profile studies demonstrated a decrease in phosphocofilin levels in all models of ischemia, implying stress-induced cofilin activation. Furthermore, calcineurin and slingshot 1L (SSH) phosphatases were found to be the signaling mediators of the cofilin activation. In primary cultures of cortical neurons, cofilin was found to be significantly activated after 1 h of OGD. To delineate the role of activated cofilin in ischemia, we knocked down cofilin by small interfering RNA (siRNA) technique and tested the impact of cofilin silencing on neuronal viability. Cofilin siRNA-treated neurons showed a significant reduction of cofilin levels in all treatment groups (control, OGD, and OGD/R). Additionally, cofilin siRNA-reduced cofilin mitochondrial translocation and caspase 3 cleavage, with a concomitant increase in neuronal viability. These results strongly support the active role of cofilin in ischemia-induced neuronal degeneration and apoptosis. We believe that targeting this protein mediator has a potential for therapeutic intervention in ischemic brain injury and stroke.

  10. Protective effects of antioxidants on high Glucose-induced malfunctions in human glomerular mesangial cells

    Directory of Open Access Journals (Sweden)

    Hosseini R

    2000-08-01

    Full Text Available Altered functions of mesangial cells induced by high glucose concentrations are thought to play an important role in the pathogenesis of diabetic nephropathy. We therefore investigated the effect of high glucose (39.2 mM alone and in combination with taurine (500 µM or vitamin E (100 µM in serum free medium (RPMI 1640 on the proliferative growth response and turnover of type IV collagen by human glomerular mesangial cells (GMC. The results showed that the high glucose level decreases the proliferation of the GMC which is reversed by taurine and vitamin E. In order to control the osmotic effects of high glucose, the GMC were also cultured in the presence of manitol. Manitol had no effect on the proliferation of GMC. Furthermore, the results showed that addition of vitamin E or taurine to media containing high glucose could reverse and normalize the collagen turn-over by the cultured mesangial cells. These results suggest that taurie and vitamin E may function as endogenous agents in the kidney to limit the development of glomerulosclerosis in diabetic renal disease.

  11. NLRP3 Inflammasome Expression and Signaling in Human Diabetic Wounds and in High Glucose Induced Macrophages

    Directory of Open Access Journals (Sweden)

    Xiaotian Zhang

    2017-01-01

    Full Text Available Introduction. To investigate the contribution and mechanism of NLRP3 inflammasome expression in human wounds in diabetes mellitus and in high glucose induced macrophages. Methods. In the present study, we compared the expression of NLRP3 inflammasome in debridement wound tissue from diabetic and nondiabetic patients. We also examined whether high glucose induces NLRP3 inflammasome expression in cultures THP-1-derived macrophages and the influence on IL-1β expression. Results. The expressions of NLRP3, caspase1, and IL-1β, at both the mRNA and protein level, were significantly higher in wounds of diabetic patients compared with nondiabetic wounds (P<0.05. High glucose induced a significant increase in NLRP3 inflammasome and IL-1β expression in THP-1-derived macrophages. M1 macrophage surface marker with CCR7 was significantly upregulated after high glucose stimulation. SiRNA-mediated silencing of NLRP3 expression downregulates the expression of IL-1β. Conclusion. The higher expression of NLRP3, caspase1, and secretion of IL-1β, signaling, and activation might contribute to the hyperinflammation in the human diabetic wound and in high glucose induced macrophages. It may be a novel target to treat the DM patients with chronic wound.

  12. Regulation of Autophagy by High Glucose in Human Retinal Pigment Epithelium

    Directory of Open Access Journals (Sweden)

    Jin Yao

    2014-01-01

    Full Text Available Background: Autophagy is a self-degradative process that is important for balancing sources of energy at critical times in development and in response to nutrient stress. Retinal pigment epithelium (RPE works as the outer blood retina barrier and is vulnerable to energy stress-induced injury. However, the effect of high glucose treatment on autophagy is still unclear in RPE. Methods: Transmission electron microscopy was used to detect the generation of autophagosome. Small interfering RNA (siRNA and MTT was used to determine the effect of autophagy on cell viability. Western blots and immunohistochemistry were used to detect the expression pattern of autophagic markers, including LC3 and p62. Results: High glucose treatment results in a significant increase in the generation of autophagosome and altered expression of LC3 and p62. High glucose-induced autophagy is independent of mTOR signaling, but is mainly regulated via ROS-mediated ER stress signaling. Conclusion: In the scenario of high glucose-induced oxidative stress, autophagy may be required for the removal of damaged proteins, and provide a default mechanism to prevent high glucose-induced injury in RPE.

  13. High Glucose Induces Sumoylation of Smad4 via SUMO2/3 in Mesangial Cells

    Directory of Open Access Journals (Sweden)

    Xueqin Zhou

    2014-01-01

    Full Text Available Recent studies have shown that sumoylation is a posttranslational modification involved in regulation of the transforming growth factor-β (TGF-β signaling pathway, which plays a critical role in renal fibrosis in diabetic nephropathy (DN. However, the role of sumoylation in the regulation of TGF-β signaling in DN is still unclear. In the present study, we investigated the expression of SUMO (SUMO1 and SUMO2/3 and Smad4 and the interaction between SUMO and Smad4 in cultured rat mesangial cells induced by high glucose. We found that SUMO1 and SUMO2/3 expression was significantly increased in the high glucose groups compared to the normal group P<0.05. Smad4 and fibronectin (FN levels were also increased in the high glucose groups in a dose-dependent manner. Coimmunoprecipitation and confocal laser scanning revealed that Smad4 interacted and colocalized with SUMO2/3, but not with SUMO1 in mesangial cells. Sumoylation (SUMO2/3 of Smad4 under high glucose condition was strongly enhanced compared to normal control P<0.05. These results suggest that high glucose may activate TGF-β/Smad signaling through sumoylation of Samd4 by SUMO2/3 in mesangial cells.

  14. Effects of Danggui Buxue Tang, a traditional Chinese herbal decoction, on high glucose-induced proliferation and expression of extracellular matrix proteins in glomerular mesangial cells.

    Science.gov (United States)

    Ke, Hao-Liang; Zhang, Ying-Wen; Zhou, Bi-Fa; Zhen, Rui-Tang

    2012-01-01

    Diabetic nephropathy (DN) is the leading cause of end-stage failure of the kidney, but the efficacy of currently available strategies for the prevention of DN remains unsatisfactory. In this study, we investigated the effects of Danggui Buxue Tang (DBT), a Chinese herbal decoction prepared from Radix Astragali (RA) and Radix Angelicae sinensis (RAS), on high glucose-induced proliferation and expression of laminin, type IV collagen (collagen IV) and fibronectin in glomerular mesangial cells (GMCs). The cell proliferation was determined by MTT assay, and the expression of collagen IV, laminin and fibronectin in GMCs was detected by ELISA assay. It was shown that high glucose clearly induced the proliferation of GMCs and increased the release of collagen IV, laminin and fibronectin. Treatment with RA, RAS and DBT inhibited cell proliferation and the expression of collagen IV, laminin and fibronectin induced by high glucose, with DBT, especially at the highest concentration (DBT20), exhibiting a stronger effect than RA and RAS alone. Thus, it is concluded that DBT inhibits increased cell proliferation and the expression of major extracellular matrix proteins that are induced by high glucose, indicating its value for prophylaxis and therapy of DN at the early stages.

  15. Canagliflozin Lowers Postprandial Glucose and Insulin by Delaying Intestinal Glucose Absorption in Addition to Increasing Urinary Glucose Excretion

    Science.gov (United States)

    Polidori, David; Sha, Sue; Mudaliar, Sunder; Ciaraldi, Theodore P.; Ghosh, Atalanta; Vaccaro, Nicole; Farrell, Kristin; Rothenberg, Paul; Henry, Robert R.

    2013-01-01

    OBJECTIVE Canagliflozin, a sodium glucose cotransporter (SGLT) 2 inhibitor, is also a low-potency SGLT1 inhibitor. This study tested the hypothesis that intestinal canagliflozin levels postdose are sufficiently high to transiently inhibit intestinal SGLT1, thereby delaying intestinal glucose absorption. RESEARCH DESIGN AND METHODS This two-period, crossover study evaluated effects of canagliflozin on intestinal glucose absorption in 20 healthy subjects using a dual-tracer method. Placebo or canagliflozin 300 mg was given 20 min before a 600-kcal mixed-meal tolerance test. Plasma glucose, 3H-glucose, 14C-glucose, and insulin were measured frequently for 6 h to calculate rates of appearance of oral glucose (RaO) in plasma, endogenous glucose production, and glucose disposal. RESULTS Compared with placebo, canagliflozin treatment reduced postprandial plasma glucose and insulin excursions (incremental 0- to 2-h area under the curve [AUC0–2h] reductions of 35% and 43%, respectively; P Canagliflozin reduced AUC RaO by 31% over 0 to 1 h (geometric means, 264 vs. 381 mg/kg; P canagliflozin increased RaO such that total AUC RaO over 0 to 6 h was Canagliflozin reduces postprandial plasma glucose and insulin by increasing UGE (via renal SGLT2 inhibition) and delaying RaO, likely due to intestinal SGLT1 inhibition. PMID:23412078

  16. Proanthocyanidins Prevent High Glucose-Induced Eye Malformation by Restoring Pax6 Expression in Chick Embryo

    Directory of Open Access Journals (Sweden)

    Rui-Rong Tan

    2015-08-01

    Full Text Available Gestational diabetes mellitus (GDM is one of the leading causes of offspring malformations, in which eye malformation is an important disease. It has raised demand for therapy to improve fetal outcomes. In this study, we used chick embryo to establish a GDM model to study the protective effects of proanthocyanidins on eye development. Chick embryos were exposed to high glucose (0.2 mmol/egg on embryo development day (EDD 1. Proanthocyanidins (1 and 10 nmol/egg were injected into the air sac on EDD 0. Results showed that both dosages of proanthocyanidins could prevent the eye malformation and rescue the high glucose-induced oxidative stress significantly, which the similar effects were showed in edaravone. However, proanthocyanidins could not decrease the glucose concentration of embryo eye. Moreover, the key genes regulating eye development, Pax6, was down-regulated by high glucose. Proanthocyanidins could restore the suppressed expression of Pax6. These results indicated proanthocyanidins might be a promising natural agent to prevent high glucose-induced eye malformation by restoring Pax6 expression.

  17. Fabrication of CuO nanoplatelets for highly sensitive enzyme-free determination of glucose

    Energy Technology Data Exchange (ETDEWEB)

    Wang Juan [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China); Zhang Weide, E-mail: zhangwd@scut.edu.cn [School of Chemistry and Chemical Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510640 (China)

    2011-09-01

    Highlights: > Adhered growth of CuO nanoplatelets on Cu foils. > Enzyme-free glucose sensor with very high sensitivity. > Excellent stability and good anti-interference ability. - Abstract: CuO nanoplatelets were grown on Cu foils by a one step, template free process. The structure and morphology of the CuO nanoplatelets were characterized by X-ray diffraction, scanning and transmission electron microscopy. The CuO nanoplatelets grown on Cu foil were integrated to be an electrode for glucose sensing. The electrocatalytic activity of the CuO nanoplatelets electrode for glucose in alkaline media was investigated by cyclic voltammetry and chronoamperometry. The electrode exhibits a sensitivity of 3490.7 {mu}A mM{sup -1} cm{sup -2} to glucose which is much higher than that of most reported enzyme-free glucose sensors and the linear range was obtained over a concentration up to 0.80 mM with a detection limit of 0.50 {mu}M (signal/noise = 3). Exhilaratingly, the electrode based on the CuO nanoplatelets is resistant against poisoning by chloride ion, and the interference from the oxidation of common interfering species, such as uric acid, ascorbic acid, dopamine and carbonhydrate compounds, can also be effectively avoided. Finally, the electrode was applied to analyze glucose concentration in human serum samples.

  18. High density lipoprotein (HDL promotes glucose uptake in adipocytes and glycogen synthesis in muscle cells.

    Directory of Open Access Journals (Sweden)

    Qichun Zhang

    Full Text Available BACKGROUND: High density lipoprotein (HDL was reported to decrease plasma glucose and promote insulin secretion in type 2 diabetes patients. This investigation was designed to determine the effects and mechanisms of HDL on glucose uptake in adipocytes and glycogen synthesis in muscle cells. METHODS AND RESULTS: Actions of HDL on glucose uptake and GLUT4 translocation were assessed with 1-[(3H]-2-deoxyglucose and plasma membrane lawn, respectively, in 3T3-L1 adipocytes. Glycogen analysis was performed with amyloglucosidase and glucose oxidase-peroxidase methods in normal and palmitate-treated L6 cells. Small interfering RNA was used to observe role of scavenger receptor type I (SR-BI in glucose uptake of HDL. Corresponding signaling molecules were detected by immunoblotting. HDL stimulated glucose uptake in a time- and concentration-dependent manner in 3T3-L1 adipocytes. GLUT4 translocation was significantly increased by HDL. Glycogen deposition got enhanced in L6 muscle cells paralleling with elevated glycogen synthase kinase3 (GSK3 phosphorylation. Meanwhile, increased phosphorylations of Akt-Ser473 and AMP activated protein kinase (AMPK α were detected in 3T3-L1 adipocytes. Glucose uptake and Akt-Ser473 activation but not AMPK-α were diminished in SR-BI knock-down 3T3-L1 cells. CONCLUSIONS: HDL stimulates glucose uptake in 3T3-L1 adipocytes through enhancing GLUT4 translocation by mechanisms involving PI3K/Akt via SR-BI and AMPK signaling pathways, and increases glycogen deposition in L6 muscle cells through promoting GSK3 phosphorylation.

  19. Tin-containing zeolites are highly active catalysts for the isomerization of glucose in water

    Energy Technology Data Exchange (ETDEWEB)

    Moliner, Manuel [California Inst. of Technology (CalTech), Pasadena, CA (United States); Roman-Leshkov, Yuriy [California Inst. of Technology (CalTech), Pasadena, CA (United States); Davis, Mark E. [California Inst. of Technology (CalTech), Pasadena, CA (United States)

    2010-04-06

    The isomerization of glucose into fructose is a large-scale reaction for the production of high-fructose corn syrup (HFCS; reaction performed by enzyme catalysts) and recently is being considered as an intermediate step in the possible route of biomass to fuels and chemicals. Here, it is shown that a large-pore zeolite that contains tin (Sn-Beta) is able to isomerize glucose to fructose in aqueous media with high activity and selectivity. Specifically, a 10% (wt/wt) glucose solution containing a catalytic amount of Sn-Beta (1:50 Sn:glucose molar ratio) gives product yields of approximately 46% (wt/wt) glucose, 31% (wt/wt) fructose, and 9% (wt/wt) mannose after 30 min and 12 min of reaction at 383 K and 413 K, respectively. This reactivity is achieved also when a 45 wt% glucose solution is used. The properties of the large-pore zeolite greatly influence the reaction behavior because the reaction does not proceed with a medium-pore zeolite, and the isomerization activity is considerably lower when the metal centers are incorporated in ordered mesoporous silica (MCM-41). The Sn-Beta catalyst can be used for multiple cycles, and the reaction stops when the solid is removed, clearly indicating that the catalysis is occurring heterogeneously. Most importantly, the Sn-Beta catalyst is able to perform the isomerization reaction in highly acidic, aqueous environments with equivalent activity and product distribution as in media without added acid. This enables Sn-Beta to couple isomerizations with other acid-catalyzed reactions, including hydrolysis/isomerization or isomerization/dehydration reaction sequences [starch to fructose and glucose to 5-hydroxymethylfurfural (HMF) demonstrated here].

  20. Marked hyperleptinemia after high-fat diet associated with severe glucose intolerance in mice

    NARCIS (Netherlands)

    Ahren, B.; Scheurink, A.J.W.

    1998-01-01

    We asked whether the likelihood for mice of the C57BL/6J strain to develop glucose intolerance when fed a high-fat diet is related to the increase in circulating levels of leptin or free fatty acids (FFA). We therefore administered a high-fat diet (58% fat) or a control diet (11% fat) for 1.5 years.

  1. Protective effect of trans-δ-viniferin against high glucose-induced oxidative stress in human umbilical vein endothelial cells through the SIRT1 pathway.

    Science.gov (United States)

    Zhao, Huijun; Ma, Ting; Fan, Boyi; Yang, Lei; Han, Chao; Luo, Jianguang; Kong, Lingyi

    2016-01-01

    Oxidative stress plays a critical role in the pathogenesis of diabetic vascular complications. Trans-δ-viniferin (TVN), a polyphenolic compound, has recently attracted much attention as an antioxidant exhibiting a hypoglycemic potential. In the present study, we aimed at investigating the protective effect of TVN against high glucose-induced oxidative stress in human umbilical vein endothelial cells (HUVECs) and the potential mechanism involved. We found that TVN attenuated reactive oxygen species (ROS) production, increased catalase (CAT) activity and decreased malondialdehyde (MDA) levels to ameliorate cell survival induced by 35 mM glucose. Meanwhile, it inhibited high glucose-induced apoptosis by maintaining Ca(2+) and preserving mitochondrial membrane potential (MMP) levels. The immunoblot analysis indicated that TVN efficiently regulated the cleavage of caspase family, p53, Bax and Bcl-2, all mediated by SIRT1. Furthermore, the increased level of SIRT1 induced by TVN was inhibited by nicotinamide and siRNA-medicated SIRT1 silencing (si-SIRT1), thereby confirming the significant role of SIRT1 in these events. In conclusion, our results indicated that TVN efficiently reduced oxidative stress and maintained mitochondrial function related with activating SIRT1 in high glucose-treated HUVECs. It suggested that TVN is pharmacologically promising for treating diabetic cardiovascular complications.

  2. High environmental temperature increases glucose requirement in the developing chicken embryo.

    Directory of Open Access Journals (Sweden)

    Roos Molenaar

    Full Text Available Environmental conditions during the perinatal period influence metabolic and developmental processes in mammals and avian species, which could impact pre- and postnatal survival and development. The current study investigated the effect of eggshell temperature (EST on glucose metabolism in broiler chicken embryos. Broiler eggs were incubated at a high (38.9°C or normal (37.8°C EST from day 10.5 of incubation onward and were injected with a bolus of [U-(13C]glucose in the chorio-allantoic fluid at day 17.5 of incubation. After [U-(13C]glucose administration, (13C enrichment was determined in intermediate pools and end-products of glucose metabolism. Oxidation of labeled glucose occurred for approximately 3 days after injection. Glucose oxidation was higher in the high than in the normal EST treatment from day 17.6 until 17.8 of incubation. The overall recovery of (13CO2 tended to be 4.7% higher in the high than in the normal EST treatment. An increase in EST (38.9°C vs 37.8°C increased (13C enrichment in plasma lactate at day 17.8 of incubation and (13C in hepatic glycogen at day 18.8 of incubation. Furthermore, high compared to normal EST resulted in a lower yolk-free body mass at day 20.9 (-2.74 g and 21.7 (-3.81 g of incubation, a lower hepatic glycogen concentration at day 18.2 (-4.37 mg/g and 18.8 (-4.59 mg/g of incubation, and a higher plasma uric acid concentration (+2.8 mg/mL/+43% at day 21.6 of incubation. These results indicate that the glucose oxidation pattern is relatively slow, but the intensity increased consistently with an increase in developmental stage of the embryo. High environmental temperatures in the perinatal period of chicken embryos increased glucose oxidation and decreased hepatic glycogen prior to the hatching process. This may limit glucose availability for successful hatching and could impact body development, probably by increased gluconeogenesis from glucogenic amino acids to allow anaerobic glycolysis.

  3. Diets high and low in glycemic index versus high monounsaturated fat diets: effects on glucose and lipid metabolism in NIDDM.

    Science.gov (United States)

    Luscombe, N D; Noakes, M; Clifton, P M

    1999-06-01

    To examine the relative effects of high and low glycemic index (GI) carbohydrates, and monounsaturated fats on blood glucose and lipid metabolism in NIDDM subjects. Fourteen male and seven female variably controlled NIDDM subjects recruited by advertisement. Free living outpatients. A repeated measures, within-subject design was used such that each subject consumed three diets: (a) a high-GI diet (53% CHO -21% fat, 63 GI units (glucose= 100)); (b) a low-GI diet (51% CHO -23% fat, 43 GI units); and (c) a high-mono high-GI diet (42% CHO -35% fat, 59 GI units) in random order and cross-over fashion for four weeks. Approximately 45% energy was provided as key foods which differed in published GI values and specifically excluded legumes. Dietary fibre intake was > 30 g/d on each diet. At the end of each dietary intervention, we measured fasting plasma lipids, glucose, insulin, total glycated plasma protein, fructosamine, LDL and HDL particle size as well as 24 h urinary excretion of glucose and C-peptide. HDL-cholesterol was higher on the low-GI and high-mono high-GI diets compared to the high-GI diet (P < 0.05 for overall diet effect). There were no other significant differences in metabolic control between diets, even when adjusted for BMI, glucose control or gender. Body weight and saturated fat intake remained stable between dietary interventions. High-mono high-GI and high-CHO, low-GI diets are superior to high-CHO, high-GI diets with respect to HDL metabolism but no effect was noted on glucose metabolism in variably controlled NIDDM subjects.

  4. High molecular weight polysaccharide that binds and inhibits virus

    Science.gov (United States)

    Konowalchuk, Thomas W

    2014-01-14

    This invention provides a high molecular weight polysaccharide capable of binding to and inhibiting virus and related pharmaceutical formulations and methods on inhibiting viral infectivity and/or pathogenicity, as well as immunogenic compositions. The invention further methods of inhibiting the growth of cancer cells and of ameliorating a symptom of aging. Additionally, the invention provides methods of detecting and/or quantifying and/or isolating viruses.

  5. High molecular weight polysaccharide that binds and inhibits virus

    Energy Technology Data Exchange (ETDEWEB)

    Konowalchuk, Thomas W.; Konowalchuk, Jack

    2017-07-18

    This invention provides a high molecular weight polysaccharide capable of binding to and inhibiting virus and related pharmaceutical formulations and methods of inhibiting viral infectivity and/or pathogenicity, as well as immunogenic compositions. The invention further includes methods of inhibiting the growth of cancer cells and of ameliorating a symptom of aging. Additionally, the invention provides methods of detecting and/or quantifying and/or isolating viruses.

  6. Fed-Batch Enzymatic Saccharification of High Solids Pretreated Lignocellulose for Obtaining High Titers and High Yields of Glucose.

    Science.gov (United States)

    Jung, Young Hoon; Park, Hyun Min; Kim, Dong Hyun; Yang, Jungwoo; Kim, Kyoung Heon

    2017-01-11

    To reduce the distillation costs of cellulosic ethanol, it is necessary to produce high sugar titers in the enzymatic saccharification step. To obtain high sugar titers, high biomass loadings of lignocellulose are necessary. In this study, to overcome the low saccharification yields and the low operability of high biomass loadings, a fed-batch saccharification process was developed using an enzyme reactor that was designed and built in-house. After optimizing the cellulase and biomass feeding profiles and the agitation speed, 132.6 g/L glucose and 76.0% theoretical maximum glucose were obtained from the 60 h saccharification of maleic acid-pretreated rice straw at a 30% (w/v) solids loading with 15 filter paper units (FPU) of Cellic CTec2/g glucan. This study demonstrated that through the proper optimization of fed-batch saccharification, both high sugar titers and high saccharification yields are possible, even with using the high solids loading (i.e., ≥30%) with the moderate enzyme loading (i.e., high solids saccharification process in cellulosic fuel and chemical production.

  7. On-chip highly sensitive saliva glucose sensing using multilayer films composed of single-walled carbon nanotubes, gold nanoparticles, and glucose oxidase

    Directory of Open Access Journals (Sweden)

    Wenjun Zhang

    2015-06-01

    Full Text Available It is very important for human health to rapidly and accurately detect glucose levels in biological environments, especially for diabetes mellitus. We proposed a simple, highly sensitive, accurate, convenient, low-cost, and disposable glucose biosensor on a single chip. A working (sensor electrode, a counter electrode, and a reference electrode are integrated on a single chip through micro-fabrication. The working electrode is functionalized through a layer-by-layer (LBL assembly of single-walled carbon nanotubes (SWNTs and multilayer films composed of chitosan (CS, gold nanoparticles (GNp, and glucose oxidase (GOx to obtain high sensitivity and accuracy. The glucose sensor has following features: (1 direct electron transfer between GOx and the electrode surface; (2 on-a-chip; (3 glucose detection down to 0.1 mg/dL (5.6 μM; (4 good sensing linearity over 0.017–0.81 mM; (5 high sensitivity (61.4 μA/mM-cm2 with a small reactive area (8 mm2; (6 fast response; (7 high reproducibility and repeatability; (8 reliable and accurate saliva glucose detection. Thus, this disposable biosensor will be an alternative for real time tracking of glucose levels from body fluids, e.g. saliva, in a noninvasive, pain-free, accurate, and continuous way. In addition to being used as a disposable glucose biosensor, it also provides a suitable platform for on-chip electrochemical sensing for other chemical agents and biomolecules.

  8. Altered multiaxial mechanical properties of the porcine anterior lens capsule cultured in high glucose.

    Science.gov (United States)

    Pedrigi, R M; Staff, E; David, G; Glenn, S; Humphrey, J D

    2007-02-01

    Hyperglycemia can alter the mechanical properties of tissues through the formation of advanced glycation endproducts in matrix proteins that have long half-lives. We used a custom experimental system and subdomain finite element method to quantify alterations in the regional multiaxial mechanical properties of porcine lens capsules that were cultured for 8 or 14 weeks in high glucose versus control media. Findings revealed that high glucose significantly stiffened the capsules in both the circumferential and the meridional directions, but it did not affect the known regional variations in anisotropy. Such information could be important in the design of both improved clinical procedures and intraocular implants for diabetic patients.

  9. The salivary microbiome is altered in the presence of a high salivary glucose concentration

    Science.gov (United States)

    Hartman, Mor-Li; Shi, Ping; Hasturk, Hatice; Yaskell, Tina; Vargas, Jorel; Song, Xiaoqing; Cugini, Maryann; Barake, Roula; Alsmadi, Osama; Al-Mutawa, Sabiha; Ariga, Jitendra; Soparkar, Pramod; Behbehani, Jawad; Behbehani, Kazem

    2017-01-01

    Background Type II diabetes (T2D) has been associated with changes in oral bacterial diversity and frequency. It is not known whether these changes are part of the etiology of T2D, or one of its effects. Methods We measured the glucose concentration, bacterial counts, and relative frequencies of 42 bacterial species in whole saliva samples from 8,173 Kuwaiti adolescents (mean age 10.00 ± 0.67 years) using DNA probe analysis. In addition, clinical data related to obesity, dental caries, and gingivitis were collected. Data were compared between adolescents with high salivary glucose (HSG; glucose concentration ≥ 1.0 mg/d, n = 175) and those with low salivary glucose (LSG, glucose concentration gingivitis in the study population. The overall salivary bacterial load in saliva decreased with increasing salivary glucose concentration. Under HSG conditions, the bacterial count for 35 (83%) of 42 species was significantly reduced, and relative bacterial frequencies in 27 species (64%) were altered, as compared with LSG conditions. These alterations were stronger predictors of high salivary glucose than measures of oral disease, obesity, sleep or fitness. Conclusions HSG was associated with a reduction in overall bacterial load and alterations to many relative bacterial frequencies in saliva when compared with LSG in samples from adolescents. We propose that hyperglycemia due to obesity and/or T2D results in HSG and subsequent acidification of the oral environment, leading to a generalized perturbation in the oral microbiome. This suggests a basis for the observation that hyperglycemia is associated with an increased risk of dental erosion, dental caries, and gingivitis. We conclude that HSG in adolescents may be predicted from salivary microbial diversity or frequency, and that the changes in the oral microbial composition seen in adolescents with developing metabolic disease may the consequence of hyperglycemia. PMID:28249034

  10. Fabrication of interdigitated high-performance zinc oxide nanowire modified electrodes for glucose sensing.

    Science.gov (United States)

    Haarindraprasad, R; Hashim, Uda; Gopinath, Subash C B; Perumal, Veeradasan; Liu, Wei-Wen; Balakrishnan, S R

    2016-06-21

    Diabetes is a metabolic disease with a prolonged elevated level of glucose in the blood leads to long-term complications and increases the chances for cardiovascular diseases. The present study describes the fabrication of a ZnO nanowire (NW)-modified interdigitated electrode (IDE) to monitor the level of blood glucose. A silver IDE was generated by wet etching-assisted conventional lithography, with a gap between adjacent electrodes of 98.80 μm. The ZnO-based thin films and NWs were amended by sol-gel and hydrothermal routes. High-quality crystalline and c-axis orientated ZnO thin films were observed by XRD analyses. The ZnO thin film was annealed for 1, 3 and 5 h, yielding a good-quality crystallite with sizes of 50, 100 and 110 nm, and the band gaps were measured as 3.26, 3.20 and 3.17 eV, respectively. Furthermore, a flower-modeled NW was obtained with the lowest diameter of 21 nm. Our designed ZnO NW-modified IDE was shown to have a detection limit as low as 0.03 mg/dL (correlation coefficient = 0.98952) of glucose with a low response time of 3 s, perform better than commercial glucose meter, suitable to instantly monitor the glucose level of diabetes patients. This study demonstrated the high performance of NW-mediated IDEs for glucose sensing as alternative to current glucose sensors.

  11. Retinal proteins associated with redox regulation and protein folding play central roles in response to high glucose conditions.

    Science.gov (United States)

    Wang, Ssu-Han; Lee, Wen-Chi; Chou, Hsiu-Chuan

    2015-03-01

    Diabetic retinopathy typically causes poor vision and blindness. A previous study revealed that a high blood glucose concentration induces glycoxidation and weakens the retinal capillaries. Nevertheless, the molecular mechanisms underlying the effects of high blood glucose induced diabetic retinopathy remain to be elucidated. In the present study, we cultured the retinal pigmented epithelial cell line ARPE-19 in mannitol-balanced 5.5, 25, and 100 mM glucose media and investigated protein level alterations. Proteomic analysis revealed significant changes in 137 protein features, of which 124 demonstrated changes in a glucose concentration dependent manner. Several proteins functionally associated with redox regulation, protein folding, or the cytoskeleton are affected by increased glucose concentrations. Additional analyses also revealed that cellular oxidative stress, including endoplasmic reticulum stress, was significantly increased after treatment with high glucose concentrations. However, the mitochondrial membrane potential and cell survival remained unchanged during treatment with high glucose concentrations. To summarize, in this study, we used a comprehensive retinal pigmented epithelial cell based proteomic approach for identifying changes in protein expression associated retinal markers induced by high glucose concentrations. Our results revealed that a high glucose condition can induce cellular oxidative stress and modulate the levels of proteins with functions in redox regulation, protein folding, and cytoskeleton regulation; however, cell viability and mitochondrial integrity are not significantly disturbed under these high glucose conditions.

  12. Protective Effects of Ferulic Acid on High Glucose-Induced Protein Glycation, Lipid Peroxidation, and Membrane Ion Pump Activity in Human Erythrocytes.

    Directory of Open Access Journals (Sweden)

    Weerachat Sompong

    Full Text Available Ferulic acid (FA is the ubiquitous phytochemical phenolic derivative of cinnamic acid. Experimental studies in diabetic models demonstrate that FA possesses multiple mechanisms of action associated with anti-hyperglycemic activity. The mechanism by which FA prevents diabetes-associated vascular damages remains unknown. The aim of study was to investigate the protective effects of FA on protein glycation, lipid peroxidation, membrane ion pump activity, and phosphatidylserine exposure in high glucose-exposed human erythrocytes. Our results demonstrated that FA (10-100 μM significantly reduced the levels of glycated hemoglobin (HbA1c whereas 0.1-100 μM concentrations inhibited lipid peroxidation in erythrocytes exposed to 45 mM glucose. This was associated with increased glucose consumption. High glucose treatment also caused a significant reduction in Na+/K+-ATPase activity in the erythrocyte plasma membrane which could be reversed by FA. Furthermore, we found that FA (0.1-100 μM prevented high glucose-induced phosphatidylserine exposure. These findings provide insights into a novel mechanism of FA for the prevention of vascular dysfunction associated with diabetes.

  13. New approach to modulate retinal cellular toxic effects of high glucose using marine epa and dha

    Directory of Open Access Journals (Sweden)

    Fagon Roxane

    2011-06-01

    Full Text Available Abstract Background Protective effects of omega-3 fatty acids against cellular damages of high glucose were studied on retinal pigmented epithelial (RPE cells. Methods Retinal epithelial cells were incubated with omega-3 marine oils rich in EPA and DHA and then with high glucose (25 mM for 48 hours. Cellular responses were compared to normal glucose (5 mM: intracellular redox status, reactive oxygen species (ROS, mitochondrial succinate deshydrogenase activity, inflammatory cytokines release and caveolin-1 expression were evaluated using microplate cytometry, ELISA and flow cytometry techniques. Fatty acids incorporation in retinal cell membranes was analysed using chromatography. Results Preincubation of the cells with fish oil decreased ROS overproduction, mitochondrial alterations and TNFα release. These protective effects could be attributed to an increase in caveolin-1 expression induced by marine oil. Conclusion Marine formulations rich in omega-3 fatty acids represent a promising therapeutic approach for diabetic retinopathy.

  14. The Cytotoxic Role of Intermittent High Glucose on Apoptosis and Cell Viability in Pancreatic Beta Cells

    Directory of Open Access Journals (Sweden)

    Zhen Zhang

    2014-01-01

    Full Text Available Objectives. Glucose fluctuations are both strong predictor of diabetic complications and crucial factor for beta cell damages. Here we investigated the effect of intermittent high glucose (IHG on both cell apoptosis and proliferation activity in INS-1 cells and the potential mechanisms. Methods. Cells were treated with normal glucose (5.5 mmol/L, constant high glucose (CHG (25 mmol/L, and IHG (rotation per 24 h in 11.1 or 25 mmol/L for 7 days. Reactive oxygen species (ROS, xanthine oxidase (XOD level, apoptosis, cell viability, cell cycle, and expression of cyclinD1, p21, p27, and Skp2 were determined. Results. We found that IHG induced more significant apoptosis than CHG and normal glucose; intracellular ROS and XOD levels were more markedly increased in cells exposed to IHG. Cells treated with IHG showed significant decreased cell viability and increased cell proportion in G0/G1 phase. Cell cycle related proteins such as cyclinD1 and Skp2 were decreased significantly, but expressions of p27 and p21 were increased markedly. Conclusions. This study suggested that IHG plays a more toxic effect including both apoptosis-inducing and antiproliferative effects on INS-1 cells. Excessive activation of cellular stress and regulation of cyclins might be potential mechanism of impairment in INS-1 cells induced by IHG.

  15. Personalized metabolomics for predicting glucose tolerance changes in sedentary women after high-intensity interval training.

    Science.gov (United States)

    Kuehnbaum, Naomi L; Gillen, Jenna B; Gibala, Martin J; Britz-McKibbin, Philip

    2014-08-28

    High-intensity interval training (HIIT) offers a practical approach for enhancing cardiorespiratory fitness, however its role in improving glucose regulation among sedentary yet normoglycemic women remains unclear. Herein, multi-segment injection capillary electrophoresis-mass spectrometry is used as a high-throughput platform in metabolomics to assess dynamic responses of overweight/obese women (BMI > 25, n = 11) to standardized oral glucose tolerance tests (OGTTs) performed before and after a 6-week HIIT intervention. Various statistical methods were used to classify plasma metabolic signatures associated with post-prandial glucose and/or training status when using a repeated measures/cross-over study design. Branched-chain/aromatic amino acids and other intermediates of urea cycle and carnitine metabolism decreased over time in plasma after oral glucose loading. Adaptive exercise-induced changes to plasma thiol redox and orthinine status were measured for trained subjects while at rest in a fasting state. A multi-linear regression model was developed to predict changes in glucose tolerance based on a panel of plasma metabolites measured for naïve subjects in their untrained state. Since treatment outcomes to physical activity are variable between-subjects, prognostic markers offer a novel approach to screen for potential negative responders while designing lifestyle modifications that maximize the salutary benefits of exercise for diabetes prevention on an individual level.

  16. AMP-Activated Protein Kinase Alleviates Extracellular Matrix Accumulation in High Glucose-Induced Renal Fibroblasts through mTOR Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Xia Luo

    2015-01-01

    Full Text Available Background/Aims: Extracellular matrix accumulation contributes significantly to the pathogenesis of diabetic nephropathy. Although AMP-activated protein kinase (AMPK has been found to inhibit extracellular matrix synthesis by experiments in vivo and vitro, its role in alleviating the deposition of extracellular matrix in renal interstitial fibroblasts has not been well defined. Methods: Currently, we conducted this study to investigate the effects of AMPK on high glucose-induced extracellular matrix synthesis and involved intracellular signaling pathway by using western blot in the kidney fibroblast cell line (NRK-49f. Results: Collagen IV protein levels were significantly increased by high glucose in a time-dependent manner. This was associated with a decrease in Thr72 phosphorylation of AMPK and an increase in phosphorylation of mTOR on Ser2448. High glucose-induced extracellular matrix accumulation and mTOR activation were significantly inhibited by the co-treatment of rAAV-AMPKα1312 (encoding constitutively active AMPKα1 whereas activated by r-AAV-AMPKα1D157A (encoding dominant negative AMPKα1. In cultured renal fibroblasts, overexpression of AMPKα1D157A upregulated mTOR signaling and matrix synthesis, which were ameliorated by co-treatment with the inhibitor of mTOR, rapamycin. Conclusion: Collectively, these findings indicate that AMPK exerts renoprotective effects by inhibiting the accumulation of extracellular matrix through mTOR signaling pathway.

  17. Nrf2 deficiency improves glucose tolerance in mice fed a high-fat diet

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yu-Kun Jennifer; Wu, Kai Connie; Liu, Jie; Klaassen, Curtis D., E-mail: cklaasse@kumc.edu

    2012-11-01

    Nrf2, a master regulator of intracellular redox homeostasis, is indicated to participate in fatty acid metabolism in liver. However, its role in diet-induced obesity remains controversial. In the current study, genetically engineered Nrf2-null, wild-type (WT), and Nrf2-activated, Keap1-knockdown (K1-KD) mice were fed either a control or a high-fat Western diet (HFD) for 12 weeks. The results indicate that the absence or enhancement of Nrf2 activity did not prevent diet-induced obesity, had limited effects on lipid metabolism, but affected blood glucose homeostasis. Whereas the Nrf2-null mice were resistant to HFD-induced glucose intolerance, the Nrf2-activated K1-KD mice exhibited prolonged elevation of circulating glucose during a glucose tolerance test even on the control diet. Feeding a HFD did not activate the Nrf2 signaling pathway in mouse livers. Fibroblast growth factor 21 (Fgf21) is a liver-derived anti-diabetic hormone that exerts glucose- and lipid-lowering effects. Fgf21 mRNA and protein were both elevated in livers of Nrf2-null mice, and Fgf21 protein was lower in K1-KD mice than WT mice. The inverse correlation between Nrf2 activity and hepatic expression of Fgf21 might explain the improved glucose tolerance in Nrf2-null mice. Furthermore, a more oxidative cellular environment in Nrf2-null mice could affect insulin signaling in liver. For example, mRNA of insulin-like growth factor binding protein 1, a gene repressed by insulin in hepatocytes, was markedly elevated in livers of Nrf2-null mice. In conclusion, genetic alteration of Nrf2 does not prevent diet-induced obesity in mice, but deficiency of Nrf2 improves glucose homeostasis, possibly through its effects on Fgf21 and/or insulin signaling. -- Highlights: ► Nrf2 deficiency improves glucose tolerance in mice fed a high-fat diet. ► The anti-diabetic hormone, Fgf21, is highly expressed in livers of Nrf2-null mice. ► The absence of Nrf2 increases the insulin-regulated Igfbp-1 mRNA in liver.

  18. Canagliflozin Lowers Postprandial Glucose and Insulin by Delaying Intestinal Glucose Absorption in Addition to Increasing Urinary Glucose Excretion

    OpenAIRE

    Polidori, David; Sha, Sue; Mudaliar, Sunder; Ciaraldi, Theodore P.; Ghosh, Atalanta; Vaccaro, Nicole; Farrell, Kristin; Rothenberg, Paul; Henry, Robert R.

    2013-01-01

    OBJECTIVE Canagliflozin, a sodium glucose cotransporter (SGLT) 2 inhibitor, is also a low-potency SGLT1 inhibitor. This study tested the hypothesis that intestinal canagliflozin levels postdose are sufficiently high to transiently inhibit intestinal SGLT1, thereby delaying intestinal glucose absorption. RESEARCH DESIGN AND METHODS This two-period, crossover study evaluated effects of canagliflozin on intestinal glucose absorption in 20 healthy subjects using a dual-tracer method. Placebo or c...

  19. Canagliflozin Lowers Postprandial Glucose and Insulin by Delaying Intestinal Glucose Absorption in Addition to Increasing Urinary Glucose Excretion

    OpenAIRE

    Polidori, David; Sha, Sue; Mudaliar, Sunder; Ciaraldi, Theodore P.; Ghosh, Atalanta; Vaccaro, Nicole; Farrell, Kristin; Rothenberg, Paul; Henry, Robert R.

    2013-01-01

    OBJECTIVE Canagliflozin, a sodium glucose cotransporter (SGLT) 2 inhibitor, is also a low-potency SGLT1 inhibitor. This study tested the hypothesis that intestinal canagliflozin levels postdose are sufficiently high to transiently inhibit intestinal SGLT1, thereby delaying intestinal glucose absorption. RESEARCH DESIGN AND METHODS This two-period, crossover study evaluated effects of canagliflozin on intestinal glucose absorption in 20 healthy subjects using a dual-tracer method. Placebo or c...

  20. Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

    OpenAIRE

    Shih-Chen Shi; Chieh-Chang Su

    2016-01-01

    The corrosion inhibition characteristics of the derivatives of biopolymer hydroxypropyl methylcellulose (HPMC), hydroxypropyl methylcellulose phthalate (HPMCP), and hydroxypropyl methylcellulose acetate succinate (HPMCAS) film are investigated. Based on electrochemical impedance spectroscopic measurements and potentiodynamic polarization, the corrosion inhibition performance of high speed steel coated with HPMC derivatives is evaluated. The Nyquist plot and Tafel polarization demonstrate prom...

  1. Particulate matter exposure exacerbates high glucose-induced cardiomyocyte dysfunction through ROS generation.

    Directory of Open Access Journals (Sweden)

    Li Zuo

    Full Text Available Diabetes mellitus and fine particulate matter from diesel exhaust (DEP are both important contributors to the development of cardiovascular disease (CVD. Diabetes mellitus is a progressive disease with a high mortality rate in patients suffering from CVD, resulting in diabetic cardiomyopathy. Elevated DEP levels in the air are attributed to the development of various CVDs, presumably since fine DEP (<2.5 µm in diameter can be inhaled and gain access to the circulatory system. However, mechanisms defining how DEP affects diabetic or control cardiomyocyte function remain poorly understood. The purpose of the present study was to evaluate cardiomyocyte function and reactive oxygen species (ROS generation in isolated rat ventricular myocytes exposed overnight to fine DEP (0.1 µg/ml, and/or high glucose (HG, 25.5 mM. Our hypothesis was that DEP exposure exacerbates contractile dysfunction via ROS generation in cardiomyocytes exposed to HG. Ventricular myocytes were isolated from male adult Sprague-Dawley rats cultured overnight and sarcomeric contractile properties were evaluated, including: peak shortening normalized to baseline (PS, time-to-90% shortening (TPS(90, time-to-90% relengthening (TR(90 and maximal velocities of shortening/relengthening (±dL/dt, using an IonOptix field-stimulator system. ROS generation was determined using hydroethidine/ethidium confocal microscopy. We found that DEP exposure significantly increased TR(90, decreased PS and ±dL/dt, and enhanced intracellular ROS generation in myocytes exposed to HG. Further studies indicated that co-culture with antioxidants (0.25 mM Tiron and 0.5 mM N-Acetyl-L-cysteine completely restored contractile function in DEP, HG and HG+DEP-treated myocytes. ROS generation was blocked in HG-treated cells with mitochondrial inhibition, while ROS generation was blocked in DEP-treated cells with NADPH oxidase inhibition. Our results suggest that DEP exacerbates myocardial dysfunction in isolated

  2. Brazilein inhibits neuronal inflammation induced by cerebral ischemia and oxygen-glucose deprivation through targeting NOD2 expression.

    Science.gov (United States)

    Yan, Xiao-Jin; Chai, Yu-Shuang; Yuan, Zhi-Yi; Wang, Xin-Pei; Jiang, Jing-Fei; Lei, Fan; Xing, Dong-Ming; DU, Li-Jun

    2016-05-01

    Brazilein is reported to have immunosuppressive effect on cardiovascular and cerebral-vascular diseases. The essential roles of innate immunity in cerebral ischemia are increasingly identified, but no studies concerning the influence of brazilein on the innate immunity receptors have been reported. The present study was designed to investigate the regulation of NOD2 (Nucleotide-binding oligomerization domain-containing protein 2) by brazilein for its protection of neuron in cerebral ischemia in vivo and oxygen-glucose deprivation in vitro. The results showed that brazilein could reverse the elevated expression of NOD2 and TNFα (tumor necrosis factor alpha) elicited by cerebral ischemia and reperfusion. This reduction could also be detected in normal mice and C17.2 cells, indicating that this suppressive effect of brazilein was correlated with NOD2. The results from GFP reporter plasmid assay suggested brazilein inhibited NOD2 gene transcription. In conclusion, brazilein could attenuate NOD2 and TNFα expression in cerebral ischemia and NOD2 may be one possible target of brazilein for its immune suppressive effect in neuro-inflammation.

  3. Biological and virulence characteristics of Salmonella enterica serovar Typhimurium following deletion of glucose-inhibited division (gidA) gene.

    Science.gov (United States)

    Shippy, Daniel C; Eakley, Nicholas M; Bochsler, Philip N; Chopra, Ashok K; Fadl, Amin A

    2011-06-01

    Salmonella enterica serovar Typhimurium is a frequent cause of enteric disease due to the consumption of contaminated food. Identification and characterization of bacterial factors involved in Salmonella pathogenesis would help develop effective strategies for controlling salmonellosis. To investigate the role of glucose-inhibited division gene (gidA) in Salmonella virulence, we constructed a Salmonella mutant strain in which gidA was deleted. Deletion of gidA rendered Salmonella deficient in the invasion of intestinal epithelial cells, bacterial motility, intracellular survival, and induction of cytotoxicity in host cells. Deletion of gidA rendered the organism to display a filamentous morphology compared to the normal rod-shaped nature of Salmonella. Furthermore, a significant attenuation in the induction of inflammatory cytokines and chemokines, histopathological lesions, and systemic infection was observed in mice infected with the gidA mutant. Most importantly, a significant increase in LD(50) was observed in mice infected with the gidA mutant, and mice immunized with the gidA mutant were able to survive a lethal dose of wild-type Salmonella. Additionally, deletion of gidA significantly altered the expression of several bacterial factors associated with pathogenesis as indicated by global transcriptional and proteomic profiling. Taken together, our data indicate GidA as a potential regulator of Salmonella virulence genes.

  4. Inhibition of glucose-stimulated insulin secretion by KCNJ15, a newly identified susceptibility gene for type 2 diabetes.

    Science.gov (United States)

    Okamoto, Koji; Iwasaki, Naoko; Doi, Kent; Noiri, Eisei; Iwamoto, Yasuhiko; Uchigata, Yasuko; Fujita, Toshiro; Tokunaga, Katsushi

    2012-07-01

    Potassium inwardly rectifying channel, subfamily J, member 15 (KCNJ15) is a type 2 diabetes-associated risk gene, and Kcnj15 overexpression suppresses insulin secretion in rat insulinoma (INS1) cells. The aim of the current study was to characterize the role of Kcnj15 by knockdown of this gene in vitro and in vivo. Human islet cells were used to determine the expression of KCNJ15. Expression of KCNJ15 mRNA in islets was higher in subjects with type 2 diabetes. In INS1 cells, Kcnj15 expression was induced by high glucose-containing medium. Regulation of Kcnj15 by glucose and its effect on insulin secretion were analyzed in INS1 cells and in normal mice and diabetic mice by the inactivation of Kcnj15 using small interfering RNA. Knockdown of Kcnj15 increased the insulin secretion in vitro and in vivo. KCNJ15 and Ca(2+)-sensing receptor (CsR) interact in the kidney. Binding of Kcnj15 with CsR was also detected in INS1 cells. In conclusion, downregulation of Kcnj15 leads to increased insulin secretion in vitro and in vivo. The mechanism to regulate insulin secretion involves KCNJ15 and CsR.

  5. Inhibition of IRE1 modifies effect of glucose deprivation on the expression of TNFα-related genes in U87 glioma cells

    Directory of Open Access Journals (Sweden)

    I. V. Kryvdiuk

    2015-11-01

    Full Text Available Inhibition of IRE1 (inositol requiring enzyme-1, the major signaling pathway of endoplasmic reticulum stress, significantly decreases glioma cell proliferation and tumor growth. We have studied the expression of TNFα-related genes and effect of glucose deprivation on these gene expressions in U87 glioma cells overexpressing dominant-negative IRE1 defective in both kinase and endonuclease (dn-IRE1 activity of IRE1 with hopes of elucidating its contribution to IRE1 mediated glioma growth. We have demonstrated that glucose deprivation condition leads to down-regulation of the expression of TNFRSF11B, TNFRSF1A, TNFRSF10D/TRAILR4, and LITAF genes and up-regulation of TNFRSF10B/TRAILR2/DR5 gene at the mRNA level in control glioma cells. At the same time, the expression of TNFRSF21/DR6, TNFAIP1, TNFAIP3, TRADD, and CD70/TNFSF7 genes in control glioma cells is resistant to glucose deprivation condition. The inhibition of IRE1 modifies the effect of glucose deprivation on LITAF, TNFRSF21, TNFRSF11B, and TRADD gene expressions and induces sensitivity to glucose deprivation condition the expression of TNFRSF10B, TNFRSF1A, and CD70 genes. We have also demonstrated that the expression of all studied genes is affected in glioma cells by inhibition of IRE1, except TNFRSF1A gene, as compared to control glioma cells. Moreover, the changes in the expression of TNFRSF1A, TNFRSF10D/TRAILR4, and LITAF genes induced by glucose deprivation condition have opposite orientation to that induced by inhibition of IRE1. The present study demonstrates that fine-tuning of the expression of TNFα-induced proteins and TNF receptor superfamily genes, which related to cell death and proliferation, is regulated by IRE1, an effector of endoplasmic reticulum stress, as well as depends on glucose deprivation in gene specific manner. Thus, the inhibition of kinase and endoribonuclease activity of IRE1 correlates with deregulation of TNFα-induced protein genes and TNF receptor

  6. Glucose detection in a highly scattering medium with diffuse photon-pair density wave

    Directory of Open Access Journals (Sweden)

    Li-Ping Yu

    2017-01-01

    Full Text Available We propose a novel optical method for glucose measurement based on diffuse photon-pair density wave (DPPDW in a multiple scattering medium (MSM where the light scattering of photon-pair is induced by refractive index mismatch between scatters and phantom solution. Experimentally, the DPPDW propagates in MSM via a two-frequency laser (TFL beam wherein highly correlated pairs of linear polarized photons are generated. The reduced scattering coefficient μ2s′ and absorption coefficient μ2a of DPPDW are measured simultaneously in terms of the amplitude and phase measurements of the detected heterodyne signal under arrangement at different distances between the source and detection fibers in MSM. The results show that the sensitivity of glucose detection via glucose-induced change of reduced scattering coefficient (δμ2s′ is 0.049%mM−1 in a 1% intralipid solution. In addition, the linear range of δμ2s′ vs glucose concentration implies that this DPPDW method can be used to monitor glucose concentration continuously and noninvasively subcutaneously.

  7. Inhibition of protein kinase CbetaII increases glucose uptake in 3T3-L1 adipocytes through elevated expression of glucose transporter 1 at the plasma membrane.

    NARCIS (Netherlands)

    Bosch, R.R.; Bazuine, M.; Wake, M.M.; Span, P.N.; Olthaar, A.J.; Schurmann, A.; Maassen, J.A.; Hermus, A.R.M.M.; Willems, P.H.G.M.; Sweep, C.G.J.

    2003-01-01

    The mechanism via which diacylglycerol-sensitive protein kinase Cs (PKCs) stimulate glucose transport in insulin-sensitive tissues is poorly defined. Phorbol esters, such as phorbol-12-myristate-13-acetate (PMA), are potent activators of conventional and novel PKCs. Addition of PMA increases the rat

  8. Effects of high glucose on mesenchymal stem cell proliferation and differentiation

    DEFF Research Database (Denmark)

    Li, Yu-Ming; Schilling, Tatjana; Benisch, Peggy

    2007-01-01

    High glucose (HG) concentrations impair cellular functions and induce apoptosis. Exposition of mesenchymal stem cells (MSC) to HG was reported to reduce colony forming activity and induce premature senescence. We characterized the effects of HG on human MSC in vitro using telomerase-immortalized...

  9. NLRP3 Inflammasome Expression and Signaling in Human Diabetic Wounds and in High Glucose Induced Macrophages

    Science.gov (United States)

    Zhang, Xiaotian; Dai, Jiezhi; Li, Li

    2017-01-01

    Introduction. To investigate the contribution and mechanism of NLRP3 inflammasome expression in human wounds in diabetes mellitus and in high glucose induced macrophages. Methods. In the present study, we compared the expression of NLRP3 inflammasome in debridement wound tissue from diabetic and nondiabetic patients. We also examined whether high glucose induces NLRP3 inflammasome expression in cultures THP-1-derived macrophages and the influence on IL-1β expression. Results. The expressions of NLRP3, caspase1, and IL-1β, at both the mRNA and protein level, were significantly higher in wounds of diabetic patients compared with nondiabetic wounds (P CCR7 was significantly upregulated after high glucose stimulation. SiRNA-mediated silencing of NLRP3 expression downregulates the expression of IL-1β. Conclusion. The higher expression of NLRP3, caspase1, and secretion of IL-1β, signaling, and activation might contribute to the hyperinflammation in the human diabetic wound and in high glucose induced macrophages. It may be a novel target to treat the DM patients with chronic wound. PMID:28164132

  10. High glucose-induced oxidative stress increases transient receptor potential channel expression in human monocytes

    DEFF Research Database (Denmark)

    Wuensch, Tilo; Thilo, Florian; Krueger, Katharina;

    2010-01-01

    Transient receptor potential (TRP) channel-induced cation influx activates human monocytes, which play an important role in the pathogenesis of atherosclerosis. In the present study, we investigated the effects of high glucose-induced oxidative stress on TRP channel expression in human monocytes....

  11. High-Density Lipoprotein Modulates Glucose Metabolism in Patients With Type 2 Diabetes Mellitus

    NARCIS (Netherlands)

    Drew, Brian G.; Duffy, Stephen J.; Formosa, Melissa F.; Natoli, Alaina K.; Henstridge, Darren C.; Penfold, Sally A.; Thomas, Walter G.; Mukhamedova, Nigora; de Courten, Barbora; Forbes, Josephine M.; Yap, Felicia Y.; Kaye, David M.; van Hall, Gerrit; Febbraio, Mark A.; Kemp, Bruce E.; Sviridov, Dmitri; Steinberg, Gregory R.; Kingwell, Bronwyn A.

    2009-01-01

    Background-Low plasma high-density lipoprotein (HDL) is associated with elevated cardiovascular risk and aspects of the metabolic syndrome. We hypothesized that HDL modulates glucose metabolism via elevation of plasma insulin and through activation of the key metabolic regulatory enzyme, AMP-activat

  12. In Vitro Infection of Trypanosoma cruzi Causes Decrease in Glucose Transporter Protein-1 (GLUT1 Expression in Explants of Human Placental Villi Cultured under Normal and High Glucose Concentrations

    Directory of Open Access Journals (Sweden)

    Luciana Mezzano

    2012-01-01

    Full Text Available Trypanosoma cruzi, the etiologic Chagas' disease agent, induces changes in protein pattern of the human placenta syncytiotrophoblast. The glucose transporter protein-1 (GLUT1 is the primary isoform involved in transplacental glucose transport. We carried out in vitro assays to determine if T. cruzi infection would induce changes in placental GLUT1 protein expression under normal and high concentration of glucose. Using Western blot and immunohistological techniques, GLUT1 expression was determined in normal placental villi cultured under normal or high concentrations of glucose, with or without in vitro T. cruzi infection, for 24 and 48 hours. High glucose media or T. cruzi infection alone reduced GLUT1 expression. A yet more accentuated reduction was observed when infection and high glucose condition took place together. We inform, for the first time, that T. cruzi infection may induce reduction of GLUT1 expression under normal and high glucose concentrations, and this effect is synergic to high glucose concentrations.

  13. Green tea epigallocatechin gallate inhibits insulin stimulation of adipocyte glucose uptake via the 67-kilodalton laminin receptor and AMP-activated protein kinase pathways.

    Science.gov (United States)

    Hsieh, Chi-Fen; Tsuei, Yi-Wei; Liu, Chi-Wei; Kao, Chung-Cheng; Shih, Li-Jane; Ho, Low-Tone; Wu, Liang-Yi; Wu, Chi-Peng; Tsai, Pei-Hua; Chang, Hsin-Huei; Ku, Hui-Chen; Kao, Yung-Hsi

    2010-10-01

    Insulin and (-)-epigallocatechin gallate (EGCG) are reported to regulate obesity and fat accumulation, respectively. This study investigated the pathways involved in EGCG modulation of insulin-stimulated glucose uptake in 3T3-L1 and C3H10T1/2 adipocytes. EGCG inhibited insulin stimulation of adipocyte glucose uptake in a dose- and time-dependent manner. The concentration of EGCG that decreased insulin-stimulated glucose uptake by 50-60% was approximately 5-10 µM for a period of 2 h. At 10 µM, EGCG and gallic acid were more effective than (-)-epicatechin, (-)-epigallocatechin, and (-)-epicatechin 3-gallate. We identified the EGCG receptor [also known as the 67-kDa laminin receptor (67LR)] in fat cells and extended the findings for this study to clarify whether EGCG-induced changes in insulin-stimulated glucose uptake in adipocytes could be mediated through the 67LR. Pretreatment of adipocytes with a 67LR antibody, but not normal rabbit immunoglobulin, prevented the effects of EGCG on insulin-increased glucose uptake. This suggests that the 67LR mediates the effect of EGCG on insulin-stimulated glucose uptake in adipocytes. Moreover, pretreatment with an AMP-activated protein kinase (AMPK) inhibitor, such as compound C, but not with a glutathione (GSH) activator, such as N-acetyl-L-cysteine (NAC), blocked the antiinsulin effect of EGCG on adipocyte glucose uptake. These data suggest that EGCG exerts its anti-insulin action on adipocyte glucose uptake via the AMPK, but not the GSH, pathway. The results of this study possibly support that EGCG mediates fat content. © Georg Thieme Verlag KG Stuttgart · New York.

  14. Over-expression of NYGGF4 (PID1) inhibits glucose transport in skeletal myotubes by blocking the IRS1/PI3K/AKT insulin pathway.

    Science.gov (United States)

    Wu, W L; Gan, W H; Tong, M L; Li, X L; Dai, J Z; Zhang, C M; Guo, X R

    2011-03-01

    Defects in insulin-stimulated glucose uptake in muscle are the important early events in the pathogenesis of insulin resistance. NYGGF4 (also named PID1) is a recently discovered gene which is suggested to be associated with obesity-associated insulin resistance. In this study, we aimed to investigate the effects of NYGGF4 on glucose uptake and insulin signaling in rat skeletal muscle cells. Rat L6 myoblasts were transfected with either an empty vector or an NYGGF4-expressing vector and induced to differentiate into mature L6 skeletal myotubes. Glucose uptake was determined by measuring uptake of 2-deoxy-d-[(3)H] glucose. Immunoblotting was performed to detect the translocation of insulin-sensitive glucose transporter 4 (GLUT4). Immunoblotting was also used to measure phosphorylation and total protein levels of the insulin signaling proteins including insulin receptor (IR), insulin receptor substrate 1 (IRS1), Akt, extracellular signal-regulated kinase 1 and 2 (ERK1/2), p38, and c-Jun-N-terminal kinase (JNK). NYGGF4 over-expression in L6 skeletal myotubes reduced insulin-stimulated glucose uptake and impaired insulin-stimulated GLUT4 translocation. It also diminished insulin-stimulated tyrosine phosphorylation of IRS1 and serine phosphorylation of Akt without affecting the phosphorylation of IR, ERK1/2, p38, or JNK. Over-expression of NYGGF4 inhibits glucose transport in skeletal myotubes by blocking the IRS1/PI3K/AKT insulin pathway. These observations highlight the potential role of NYGGF4 in glucose homeostasis and the development of insulin resistance in obesity. Copyright © 2010 Elsevier Inc. All rights reserved.

  15. Fucoxanthin exerts differing effects on 3T3-L1 cells according to differentiation stage and inhibits glucose uptake in mature adipocytes

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Seong-Il [Department of Biology, Jeju National University, Jejusi, Jeju 690-756 (Korea, Republic of); Ko, Hee-Chul [Jeju Sasa Industry Development Agency, Jeju National University, Jejusi, Jeju 690-756 (Korea, Republic of); Shin, Hye-Sun; Kim, Hyo-Min; Hong, Youn-Suk [Department of Biology, Jeju National University, Jejusi, Jeju 690-756 (Korea, Republic of); Lee, Nam-Ho [Department of Chemistry, Jeju National University, Jejusi, Jeju 690-756 (Korea, Republic of); Kim, Se-Jae, E-mail: sjkim@jejunu.ac.kr [Department of Biology, Jeju National University, Jejusi, Jeju 690-756 (Korea, Republic of); Jeju Sasa Industry Development Agency, Jeju National University, Jejusi, Jeju 690-756 (Korea, Republic of)

    2011-06-17

    Highlights: {yields} Fucoxanthin enhances 3T3-L1 adipocyte differentiation at an early stage. {yields} Fucoxanthin inhibits 3T3-L1 adipocyte differentiation at intermediate and late stages. {yields} Fucoxanthin attenuates glucose uptake by inhibiting the phosphorylation of IRS in mature 3T3-L1 adipocytes. {yields} Fucoxanthin exerts its anti-obesity effect by inhibiting the differentiation of adipocytes at both intermediate and late stages, as well as glucose uptake in mature adipocytes. -- Abstract: Progression of 3T3-L1 preadipocyte differentiation is divided into early (days 0-2, D0-D2), intermediate (days 2-4, D2-D4), and late stages (day 4 onwards, D4-). In this study, we investigated the effects of fucoxanthin, isolated from the edible brown seaweed Petalonia binghamiae, on adipogenesis during the three differentiation stages of 3T3-L1 preadipocytes. When fucoxanthin was applied during the early stage of differentiation (D0-D2), it promoted 3T3-L1 adipocyte differentiation, as evidenced by increased triglyceride accumulation. At the molecular level, fucoxanthin increased protein expression of peroxisome proliferator-activated receptor {gamma} (PPAR{gamma}), CCAAT/enhancer-binding protein {alpha} (C/EBP{alpha}), sterol regulatory element-binding protein 1c (SREBP1c), and aP2, and adiponectin mRNA expression, in a dose-dependent manner. However, it reduced the expression of PPAR{gamma}, C/EBP{alpha}, and SREBP1c during the intermediate (D2-D4) and late stages (D4-D7) of differentiation. It also inhibited the uptake of glucose in mature 3T3-L1 adipocytes by reducing the phosphorylation of insulin receptor substrate 1 (IRS-1). These results suggest that fucoxanthin exerts differing effects on 3T3-L1 cells of different differentiation stages and inhibits glucose uptake in mature adipocytes.

  16. Archetypal sandwich-structured CuO for high performance non-enzymatic sensing of glucose.

    Science.gov (United States)

    Meher, Sumanta Kumar; Rao, G Ranga

    2013-03-07

    In the quest to enhance the selectivity and sensitivity of novel structured metal oxides for electrochemical non-enzymatic sensing of glucose, we report here a green synthesis of unique sandwich-structured CuO on a large scale under microwave mediated homogeneous precipitation conditions. The physicochemical studies carried out by XRD and BET methods show that the monoclinic CuO formed via thermal decomposition of Cu(2)(OH)(2)CO(3) possesses monomodal channel-type pores with largely improved surface area (~43 m(2) g(-1)) and pore volume (0.163 cm(3) g(-1)). The fascinating surface morphology and pore structure of CuO is formulated due to homogeneous crystallization and microwave induced self assembly during synthesis. The cyclic voltammetry and chronoamperometry studies show diffusion controlled glucose oxidation at ~0.6 V (vs. Ag/AgCl) with extremely high sensitivity of 5342.8 μA mM(-1) cm(-2) and respective detection limit and response time of ~1 μM and ~0.7 s, under a wide dynamic concentration range of glucose. The chronoamperometry measurements demonstrate that the sensitivity of CuO to glucose is unaffected by the absence of dissolved oxygen and presence of poisoning chloride ions in the reaction medium, which essentially implies high poison resistance activity of the sandwich-structured CuO. The sandwich-structured CuO also shows insignificant interference/significant selectivity to glucose, even in the presence of high concentrations of other sugars as well as reducing species. In addition, the sandwich-structured CuO shows excellent reproducibility (relative standard deviation of ~2.4% over ten identically fabricated electrodes) and outstanding long term stability (only ~1.3% loss in sensitivity over a period of one month) during non-enzymatic electrochemical sensing of glucose. The unique microstructure and suitable channel-type pore architecture provide structural stability and maximum accessible electroactive surface for unimpeded mobility of glucose

  17. The protective effect of alpha lipoic acid on Schwann cells exposed to constant or intermittent high glucose.

    Science.gov (United States)

    Sun, Lian-Qing; Chen, Ying-Ying; Wang, Xuan; Li, Xiao-Jin; Xue, Bing; Qu, Ling; Zhang, Ting-Ting; Mu, Yi-Ming; Lu, Ju-Ming

    2012-10-01

    Diabetic peripheral neuropathy (DPN) is one of the most common and costly microvascular complications of diabetes, and no effective therapy exists. Previous studies have demonstrated that oxidative stress may be the unifying factor for the damaging effect of hyperglycemia. The aim of this study was to examine the impact of treatment with Alpha lipoic acid (ALA) on the intermittent high glucose (IHG) or high glucose (HG)-induced oxidative stress-induced mitochondrial pathway activation and Schwann cells (SCs) apoptosis in vitro. Our results suggested that IHG and HG induced SCs apoptosis in both caspase-dependent and caspase-independent pathways related to oxidative stress. More importantly, the cytotoxic effect of IHG was significantly more potent than that of HG. Treatment with ALA inhibited the IHG and HG-induced oxidative stress and apoptosis in SCs. Furthermore, treatment with ALA down-regulated the Bax expression and the release of cytochrome c and AIF translocation, but up-regulated the Bcl-2 expression in SCs. Treatment with ALA attenuated the activation of caspase-3 and caspase-9 and minimized the cleavage of PARP in SCs. These findings suggest that variability in glycemic control could be more deleterious than a constant HG and ALA antagonized the IHG-induced oxidative stress, activation of mitochondrial pathway and apoptosis in SCs.

  18. Effects of macronutrient composition and cyclooxygenase-inhibition on diet-induced obesity, low grade inflammation and glucose homeostasis

    DEFF Research Database (Denmark)

    Fjære, Even

    - or protein based background, and supplemented with either corn- or fish oil. These experiments were conducted to determine whether macronutrient composition and type of dietary fat can modulate diet-induced obesity, and associated metabolic consequences. The use of non-steroidal anti-inflammatory drugs...... is escalating, and in view of the increased consumption of obesogenic diets with high levels of dietary carbohydrates and fat, the metabolic consequences of cyclooxygenase-inhibition warrants investigation. Results: High fat/high sucrose diets increased obesity development and expression of macrophage...

  19. Kinetics of Bacillus thuringiensis var. israelensis growth on high glucose concentrations.

    Science.gov (United States)

    Berbert-Molina, M A; Prata, A M R; Pessanha, L G; Silveira, M M

    2008-11-01

    The kinetic and general growth features of Bacillus thuringiensis var. israelensis were evaluated. Initial glucose concentration (S0) in fermentation media varied from 10 to 152 g/l. The results afforded to characterize four morphologically and physiologically well-defined culture phases, independent of S0 values: Phase I, vegetative growth; Phase II, transition to sporulation; Phase III, sporulation; and Phase IV, spores maturation and cell lysis. Important process parameters were also determined. The maximum specific growth rates (microX,m) were not affected with S0 up to 75 g/l (1.0-1.1 per hour), but higher glucose concentrations resulted in growth inhibition by substrate, revealed by a reduction in microX,m values. These higher S0 values led to longer Phases III and IV and delayed sporulation. Similar biomass concentrations (Xm=15.2-15.9 g/l) were achieved with S0 over 30.8 g/l, with increasing residual substrate, suggesting a limitation in some other nutrients and the use of glucose to form other metabolites. In this case, with S0 from 30.8 to 152 g/l, cell yield (YX/S) decreased from 0.58 to 0.41 g/g. On the other hand, with S0=10 g/l growth was limited by substrate, and YX/S has shown its maximum value (0.83 g/g).

  20. Erythropoietin (EPO) protects against high glucose-induced apoptosis in retinal ganglional cells.

    Science.gov (United States)

    Wang, Yunxiao; Zhang, Hui; Liu, Yanping; Li, Ping; Cao, Zhihong; Cao, Yu

    2015-03-01

    The aim of this study was to investigate the protective effect and mechanism of EPO on the apoptosis induced by high levels of glucose in retinal ganglial cells (RGCs). High glucose-induced apoptosis model was established in RGCs isolated from SD rats (1-3 days old) and identified with Thy1.1 mAb and MAP-2 pAb. The apoptosis was determined by Hochest assay. The levels of ROS were quantitated by staining the cells with dichloro-dihydro-fluorescein diacetate (DCFH-DA) and measure by flow cytometry. The SOD, GSH-Px, CAT activities, and levels of T-AOC and MDA were determined by ELISA. Change in mitochondrial membrane potential (Δψm) was also assessed by flow cytometry, and expressions of Bcl-2, Bax, caspase-3, caspase-9, and cytochrome C were assessed by western blotting. The RGCs treated with high glucose levels exhibited significantly increased apoptotic rate and concentrations of ROS and MDA. Pretreatment of the cells with EPO caused a significant blockade of the high glucose-induced increase in ROS and MDA levels and apoptotic rate. EPO also increased the activities of SOD, GSH-Px, and CAT, and recovered the levels of T-AOC levels. As a consequence, the mitochondrial membrane potential was improved and Cyt c release into the cytoplasm was prevented which led to significantly suppressed up-regulation of Bax reducing the Bax/Bcl-2 ratio. The expressions of caspase-3 and caspase-9 induced by high glucose exposure were also ameliorated in the RGCs treated with EPO. The protective effect of EPO against apoptosis was mediated through its antioxidant action. Thus, it blocked the generation of pro-apoptotic proteins and apoptotic degeneration of the RGCs by preventing the mitochondrial damage.

  1. Cobalt oxide acicular nanorods with high sensitivity for the non-enzymatic detection of glucose.

    Science.gov (United States)

    Kung, Chung-Wei; Lin, Chia-Yu; Lai, Yi-Hsuan; Vittal, R; Ho, Kuo-Chuan

    2011-09-15

    Acicular cobalt oxide nanorods (CoONRs) were prepared for the non-enzymatic detection of glucose, first by directly growing layered cobalt carbonate hydroxide (LCCH) on a conducting fluorine-doped tin oxide (FTO) substrate using a simple chemical bath deposition (CBD) technique and then by transforming the LCCH into CoONRs through pyrolysis. The composition and grain size of the films of LCCH and CoONRs were verified by X-ray diffraction (XRD); their morphologies were examined by scanning electron microscopic (SEM) and transmission electron microscopic (TEM) images. CoONRs showed high electrocatalytic activity for the electro-oxidation of glucose in alkaline media, and the activity was strongly influenced by NaOH concentration, annealing temperature of CoONRs, and thickness of CoONRs film. The pertinent sensor could be successfully used for the quantification of glucose by amperometric method. The sensing parameters include wide linear range up to 3.5 mM, a high sensitivity of 571.8 μA/(cm(2) mM), and a remarkable low detection limit of 0.058 μM. The CoONRs modified electrode exhibited a high selectivity for glucose in human serum, against ascorbic acid, uric acid, and acetaminophen.

  2. Influence of Acute High Glucose on Protein Abundance Changes in Murine Glomerular Mesangial Cells

    Directory of Open Access Journals (Sweden)

    Michelle T. Barati

    2016-01-01

    Full Text Available The effects of acute exposure to high glucose levels as experienced by glomerular mesangial cells in postprandial conditions and states such as in prediabetes were investigated using proteomic methods. Two-dimensional gel electrophoresis and matrix assisted laser desorption ionization time of flight mass spectrometry methods were used to identify protein expression patterns in immortalized rat mesangial cells altered by 2 h high glucose (HG growth conditions as compared to isoosmotic/normal glucose control (NG⁎ conditions. Unique protein expression changes at 2 h HG treatment were measured for 51 protein spots. These proteins could be broadly grouped into two categories: (1 proteins involved in cell survival/cell signaling and (2 proteins involved in stress response. Immunoblot experiments for a protein belonging to both categories, prohibitin (PHB, supported a trend for increased total expression as well as significant increases in an acidic PHB isoform. Additional studies confirmed the regulation of proteasomal subunit alpha-type 2 and the endoplasmic reticulum chaperone and oxidoreductase PDI (protein disulfide isomerase, suggesting altered ER protein folding capacity and proteasomal function in response to acute HG. We conclude that short term high glucose induces subtle changes in protein abundances suggesting posttranslational modifications and regulation of pathways involved in proteostasis.

  3. Chronic benzylamine administration in the drinking water improves glucose tolerance, reduces body weight gain and circulating cholesterol in high-fat diet-fed mice.

    Science.gov (United States)

    Iffiú-Soltész, Zsuzsa; Wanecq, Estelle; Lomba, Almudena; Portillo, Maria P; Pellati, Federica; Szöko, Eva; Bour, Sandy; Woodley, John; Milagro, Fermin I; Alfredo Martinez, J; Valet, Philippe; Carpéné, Christian

    2010-04-01

    Benzylamine is found in Moringa oleifera, a plant used to treat diabetes in traditional medicine. In mammals, benzylamine is metabolized by semicarbazide-sensitive amine oxidase (SSAO) to benzaldehyde and hydrogen peroxide. This latter product has insulin-mimicking action, and is involved in the effects of benzylamine on human adipocytes: stimulation of glucose transport and inhibition of lipolysis. This study examined whether chronic, oral administration of benzylamine could improve glucose tolerance and the circulating lipid profile without increasing oxidative stress in overweight and pre-diabetic mice. The benzylamine diffusion across the intestine was verified using everted gut sacs. Then, glucose handling and metabolic markers were measured in mice rendered insulin-resistant when fed a high-fat diet (HFD) and receiving or not benzylamine in their drinking water (3600micromol/(kgday)) for 17 weeks. HFD-benzylamine mice showed lower body weight gain, fasting blood glucose, total plasma cholesterol and hyperglycaemic response to glucose load when compared to HFD control. In adipocytes, insulin-induced activation of glucose transport and inhibition of lipolysis remained unchanged. In aorta, benzylamine treatment partially restored the nitrite levels that were reduced by HFD. In liver, lipid peroxidation markers were reduced. Resistin and uric acid, surrogate plasma markers of metabolic syndrome, were decreased. In spite of the putative deleterious nature of the hydrogen peroxide generated during amine oxidation, and in agreement with its in vitro insulin-like actions found on adipocytes, the SSAO-substrate benzylamine could be considered as a potential oral agent to treat metabolic syndrome.

  4. PERK silence inhibits glioma cell growth under low glucose stress by blockage of p-AKT and subsequent HK2's mitochondria translocation

    KAUST Repository

    Hou, Xu

    2015-03-12

    Glioma relies on glycolysis to obtain energy and sustain its survival under low glucose microenvironment in vivo. The mechanisms on glioma cell glycolysis regulation are still unclear. Signaling mediated by Double-stranded RNA-activated protein kinase (PKR) - like ER kinase (PERK) is one of the important pathways of unfolded protein response (UPR) which is comprehensively activated in cancer cells upon the hypoxic and low glucose stress. Here we show that PERK is significantly activated in human glioma tissues. PERK silencing results in decreased glioma cell viability and ATP/lactate production upon low glucose stress, which is mediated by partially blocked AKT activation and subsequent inhibition of Hexokinase II (HK2)\\'s mitochondria translocation. More importantly, PERK silenced glioma cells show decreased tumor formation capacity. Our results reveal that PERK activation is involved in glioma glycolysis regulation and may be a potential molecular target for glioma treatment.

  5. The edible red alga, Gracilaria verrucosa, inhibits lipid accumulation and ROS production, but improves glucose uptake in 3T3-L1 cells.

    Science.gov (United States)

    Woo, Mi-Seon; Choi, Hyeon-Son; Lee, Ok-Hwan; Lee, Boo-Yong

    2013-07-01

    Gracilaria verrucosa is a red alga that is widely distributed in seaside areas of many countries. We examined the effect of G. verrucosa extract on adipogenesis, reactive oxygen species (ROS) production, and glucose uptake in 3T3-L1 cells. Oil red O staining and a nitroblue tetrazolium assay showed that G. verrucosa extract inhibited lipid accumulation and ROS production, respectively. mRNA levels of adipogenic transcription factors, peroxisome proliferator-activated receptor gamma and CCAAT/enhancer-binding protein alpha, as well as of their target gene, adipocyte protein 2, were reduced upon treatment with G. verrucosa extract. However, G. verrucosa extract increased glucose uptake, glucose transporter-4 expression, and AMP-activated protein kinaseα (AMPKα) phosphorylation compared to the control. Our results suggest that the anti-adipogenic and insulin-sensitive effects of G. verrucosa extract can be recapitulated to activation of AMPKα.

  6. Inhibition of early AAA formation by aortic intraluminal pentagalloyl glucose (PGG) infusion in a novel porcine AAA model

    DEFF Research Database (Denmark)

    Kloster, Brian O; Lund, Lars; Lindholt, Jes S

    2016-01-01

    to prevent or delay their expansion. In this study, we investigated whether intraluminal delivered pentagalloyl glucose (PGG) can impair the early AAA development in a porcine model. METHODS: The infrarenal aorta was exposed in thirty pigs. Twenty underwent an elastase based AAA inducing procedure and ten...... of these received an additional intraluminal PGG infusion. The final 10 were sham operated and served as controls. RESULTS: All pigs who only had an elastase infusion developed macroscopically expanding AAAs. In pigs treated with an additional PGG infusion the growth rate of the AP-diameter rapidly returned...... and histology. CONCLUSION: In our model, intraluminal delivered PGG is able to penetrate the aortic wall from the inside and impair the early AAA development by stabilizing the elastic lamellae and preserving their integrity. The principle holds a high clinical potential if it can be translated to human...

  7. Inhibiting Notch Activity in Breast Cancer Stem Cells by Glucose Functionalized Nanoparticles Carrying γ-secretase Inhibitors.

    Science.gov (United States)

    Mamaeva, Veronika; Niemi, Rasmus; Beck, Michaela; Özliseli, Ezgi; Desai, Diti; Landor, Sebastian; Gronroos, Tove; Kronqvist, Pauliina; Pettersen, Ina K N; McCormack, Emmet; Rosenholm, Jessica M; Linden, Mika; Sahlgren, Cecilia

    2016-05-01

    Cancer stem cells (CSCs) are a challenge in cancer treatment due to their therapy resistance. We demonstrated that enhanced Notch signaling in breast cancer promotes self-renewal of CSCs that display high glycolytic activity and aggressive hormone-independent tumor growth in vivo. We took advantage of the glycolytic phenotype and the dependence on Notch activity of the CSCs and designed nanoparticles to target the CSCs. Mesoporous silica nanoparticles were functionalized with glucose moieties and loaded with a γ-secretase inhibitor, a potent interceptor of Notch signaling. Cancer cells and CSCs in vitro and in vivo efficiently internalized these particles, and particle uptake correlated with the glycolytic profile of the cells. Nanoparticle treatment of breast cancer transplants on chick embryo chorioallantoic membranes efficiently reduced the cancer stem cell population of the tumor. Our data reveal that specific CSC characteristics can be utilized in nanoparticle design to improve CSC-targeted drug delivery and therapy.

  8. A miniature glucose/O{sub 2} biofuel cell with a high tolerance against ascorbic acid

    Energy Technology Data Exchange (ETDEWEB)

    Li, X.; Zhang, L. [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing (China); Graduate School of CAS, Beijing (China); Su, L. [Beijing National Laboratory for Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences (CAS), Beijing (China); Ohsaka, T. [Department of Electronic Chemistry, Interdisciplinary Graduate School of Science and Engineering, Tokyo Institute of Technology, Midori-ku, Yokohama (Japan); Mao, L.

    2009-02-15

    This study demonstrates a miniature glucose/O{sub 2} biofuel cell (BFC) with a high tolerance against physiological level of ascorbic acid (AA) by immobilising ascorbate oxidase (AAox) on both the bioanode and the biocathode. Single-walled carbon nanotube (SWNT)-modified carbon fiber microelectrodes (CFMEs) are employed as the substrate electrode for the bioanode and biocathode. Glucose dehydrogenase (GDH) and bilirubin oxidase (BOD) are used as the biocatalysts for the electro-oxidation of glucose and for the electro-reduction of oxygen, respectively. SWNTs are used as the support for the both, stably confining the electrocatalyst (i.e. polymerised methylene blue, polyMB) for the oxidation of NADH co-factor for GDH and efficiently facilitating direct electrochemistry of the cathodic biocatalyst (i.e. BOD) for O{sub 2} reduction. The prepared micro-sized GDH-based bioanode and BOD-based biocathode employed for the bioelectrocatalytic oxidation of glucose and reduction of oxygen, respectively, are further over-coated with AAox to give a miniature glucose/O{sub 2} BFC with a high tolerance against AA. The maximum power density and the open circuit voltage (OCV) of the assembled glucose/O{sub 2} BFC are 52 {mu}W cm{sup -2} and 0.60 V, respectively. These values remain unchanged with the presence of AA in solution. In the human serum containing 10 mM NAD{sup +} and under ambient air, the maximum power density and the OCV of the assembled glucose/O{sub 2} BFC with AAox immobilisation on both the bioanode and the biocathode are 35 {mu}W cm{sup -2} and 0.39 V, respectively. These values are remarkably larger than those of the glucose/O{sub 2} BFC without AAox immobilisation on both the bioanode and the biocathode. This study could offer a new route to the development of enzymatic BFCs with promising application in real biological systems. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  9. High prevalence of abnormal circadian blood pressure regulation and impaired glucose tolerance in adults with hypopituitarism.

    Science.gov (United States)

    Krzyzanowska, K; Schnack, C; Mittermayer, F; Kopp, H P; Hofer, M; Kann, T; Schernthaner, G

    2005-09-01

    Patients with hypopituitarism have an increased mortality from cardiovascular events. Reduced nocturnal blood pressure decline (non-dipping) and impaired glucose tolerance are considered as cardiovascular risk factors. To evaluate the role of these risk factors in patients with hypopituitarism we determined the 24-hour blood pressure regulation and glucose tolerance status in hypopituitary patients with and without growth hormone (GH) deficiency. Sixty-one hypopituitary subjects 5 +/- 3 years after brain surgery because of macroadenoma, 61 patients with type 2 diabetes mellitus (T2DM), and 20 healthy controls were included. Forty-four hypopituitary patients were GH deficient and 28 of these on GH treatment. Non-dipping was observed in 41 % (n = 7) of hypopituitary subjects with normal GH release, in 46 % (n = 13) of patients on GH therapy, and in 69 % (n = 11) of untreated GH deficient patients. Untreated GH deficient patients had a higher systolic night/day ratio (1.00 +/- 0.03) compared to non GH deficient (0.92 +/- 0.02; p < 0.02) and GH treated hypopituitary patients (0.93 +/- 0.01; p < 0.02). The rate of non-dipping in hypopituitarism was comparable to that in T2DM. Pathologic glucose tolerance was diagnosed in 30 % of the hypopituitary patients. The prevalence of non-dipping was independent of glucose metabolism in hypopituitary patients. All controls had normal night time blood pressure fall and glucose metabolism. The high prevalence of nocturnal non-dipping and glucose intolerance detected in this cohort might contribute to the increased cardiovascular risk of hypopituitary patients.

  10. A highly sensitive and stable glucose biosensor using thymine-based polycations into laponite hydrogel films.

    Science.gov (United States)

    Paz Zanini, Veronica I; Gavilán, Maximiliano; López de Mishima, Beatriz A; Martino, Débora M; Borsarelli, Claudio D

    2016-04-01

    A series of glucose bioelectrodes were prepared by glucose oxidase (GOx) immobilization into laponite hydrogel films containing DNA bioinspired polycations made of vinylbenzyl thymine (VBT) and vinylbenzyl triethylammonium chloride (VBA) with general formulae (VBT)m(VBA)n](n+)≈25 with m=0, 1 and n=2, 4, 8, deposited onto glassy carbon electrode. The bioelectrodes were characterized by chronoamperometry, cyclic voltammetry and electrochemical impedance spectroscopy. Results indicated that the electrochemical properties of the laponite hydrogel films were largely improved by the incorporation of thymine-based polycations, being proportional to the positive charge density of the polycation molecule. After incorporation of glucose oxidase, the sensitivity of the bioelectrode to glucose increased with the positive charge density of the polycation. Additionally, the presence of the vinylbenzyl thymine moiety played a role in the long-term stability and reproducibility of the bioelectrode signal. As a consequence, the [(VBT)(VBA)8](8+)≈25 was the most appropriate polycation for bioelectrode preparation and glucose sensing, with a specific sensitivity of se=176 mA mmol(-1)Lcm(-2)U(-1), almost two-order of magnitude larger than other laponite immobilized GOx bioelectrodes reported elsewhere. These features were confirmed by testing the bioelectrode for a selective determination of glucose in powder milk and blood serum samples without interference of either ascorbic or uric acids under the experimental conditions. The present study demonstrates the suitability of DNA bioinspired water-soluble polycations [(VBT)m(VBA)n](n+)≈25 for enzyme immobilization like GOx into laponite hydrogels, and the preparation of highly sensitive and stable bioelectrodes on glassy carbon surface.

  11. Lin28a protects against hypoxia/reoxygenation induced cardiomyocytes apoptosis by alleviating mitochondrial dysfunction under high glucose/high fat conditions.

    Directory of Open Access Journals (Sweden)

    Mingming Zhang

    Full Text Available The aim of the present study was to investigate the role of Lin28a in protecting against hypoxia/reoxygenation (H/R-induced cardiomyocytes apoptosis under high glucose/high fat (HG/HF conditions.Primary cardiomyocytes which were isolated from neonatal mouse were randomized to be treated with lentivirus carrying Lin28a siRNA, Lin28acDNA 72 h before H/R (9 h/2 h. Cardiomyocytes biomarkers release (LDH and CK, cardiomyocytes apoptosis, mitochondria biogenesis and morphology, intracellular reactive oxygen species (ROS production, ATP content and inflammatory cytokines levels after H/R injury in high glucose/high fat conditions were compared between groups. The target proteins of Lin28a were examined by western blot analysis.Our results revealed that Lin28a cDNA transfection (overexpression significantly inhibited cardiomyocyte apoptotic index, improved mitochondria biogenesis, increased ATP production and reduced ROS production as compared with the H/R group in HG/HF conditions. Lin28a siRNA transfection (knockdown rendered the cardiomyocytes more susceptible to H/R injury as evidenced by increased apoptotic index, impaired mitochondrial biogenesis, decreased ATP production and increased ROS level. Interestingly, these effects of Lin28a were blocked by pretreatment with the PI3K inhibitor wortmannin. Lin28a overexpression increased, while Lin28a knockdown inhibited IGF1R, Nrf-1, Tfam, p-IRS-1, p-Akt, p-mTOR, p-p70s6k, p-AMPK expression levels after H/R injury in HG/HF conditions. Moreover, pretreatment with wortmannin abolished the effects of Lin28a on the expression levels of p-AKT, p-mTOR, p-p70s6k, p-AMPK.The present results suggest that Lin28a inhibits cardiomyocytes apoptosis by enhancing mitochondrial biogenesis and function under high glucose/high fat conditions. The mechanism responsible for the effects of Lin28a is associated with the PI3K/Akt dependent pathway.

  12. Lin28a protects against hypoxia/reoxygenation induced cardiomyocytes apoptosis by alleviating mitochondrial dysfunction under high glucose/high fat conditions.

    Science.gov (United States)

    Zhang, Mingming; Niu, Xiaolin; Hu, Jianqiang; Yuan, Yuan; Sun, Shuhong; Wang, Jiaxing; Yu, Wenjun; Wang, Chen; Sun, Dongdong; Wang, Haichang

    2014-01-01

    The aim of the present study was to investigate the role of Lin28a in protecting against hypoxia/reoxygenation (H/R)-induced cardiomyocytes apoptosis under high glucose/high fat (HG/HF) conditions. Primary cardiomyocytes which were isolated from neonatal mouse were randomized to be treated with lentivirus carrying Lin28a siRNA, Lin28acDNA 72 h before H/R (9 h/2 h). Cardiomyocytes biomarkers release (LDH and CK), cardiomyocytes apoptosis, mitochondria biogenesis and morphology, intracellular reactive oxygen species (ROS) production, ATP content and inflammatory cytokines levels after H/R injury in high glucose/high fat conditions were compared between groups. The target proteins of Lin28a were examined by western blot analysis. Our results revealed that Lin28a cDNA transfection (overexpression) significantly inhibited cardiomyocyte apoptotic index, improved mitochondria biogenesis, increased ATP production and reduced ROS production as compared with the H/R group in HG/HF conditions. Lin28a siRNA transfection (knockdown) rendered the cardiomyocytes more susceptible to H/R injury as evidenced by increased apoptotic index, impaired mitochondrial biogenesis, decreased ATP production and increased ROS level. Interestingly, these effects of Lin28a were blocked by pretreatment with the PI3K inhibitor wortmannin. Lin28a overexpression increased, while Lin28a knockdown inhibited IGF1R, Nrf-1, Tfam, p-IRS-1, p-Akt, p-mTOR, p-p70s6k, p-AMPK expression levels after H/R injury in HG/HF conditions. Moreover, pretreatment with wortmannin abolished the effects of Lin28a on the expression levels of p-AKT, p-mTOR, p-p70s6k, p-AMPK. The present results suggest that Lin28a inhibits cardiomyocytes apoptosis by enhancing mitochondrial biogenesis and function under high glucose/high fat conditions. The mechanism responsible for the effects of Lin28a is associated with the PI3K/Akt dependent pathway.

  13. Hyperosmolarity induced by high glucose promotes senescence in human glomerular mesangial cells.

    Science.gov (United States)

    del Nogal, Maria; Troyano, Nuria; Calleros, Laura; Griera, Mercedes; Rodriguez-Puyol, Manuel; Rodriguez-Puyol, Diego; Ruiz-Torres, María P

    2014-09-01

    Hyperglycemia is involved in the diabetic complication of different organs and can elevate serum osmolarity. Here, we tested whether hyperosmolarity promoted by high glucose levels induces cellular senescence in renal cells. We treated Wistar rats with streptozotocin to induce diabetes or with consecutive daily injections of mannitol to increase serum osmolarity and analyzed p53 and p16 genes in renal cortex by immunohistochemistry. Both diabetic and mannitol treated rats showed a significant increase in serum osmolarity, without significant signs of renal dysfunction, but associated with increased staining for p53 and p16 in the renal cortex. An increase in p53 and p16 expression was also found in renal cortex slices and glomeruli isolated from healthy rats, which were later treated with 30 mM glucose or mannitol. Intracellular mechanisms involved were analyzed in cultured human glomerular mesangial cells treated with 30 mM glucose or mannitol. After treatments, cells showed increased p53, p21 and p16 expression and elevated senescence-associated β-galactosidase activity. Senescence was prevented when myo-inositol was added before treatment. High glucose or mannitol induced constitutive activation of Ras and ERK pathways which, in turn, were activated by oxidative stress. In summary, hyperosmolarity induced renal senescence, particularly in glomerular mesangial cells, increasing oxidative stress, which constitutively activated Ras-ERK 1/2 pathway. Cellular senescence could contribute to the organ dysfunction associated with diabetes.

  14. High glucose enhance expression of matrix metalloproteinase—2 in smooth muscle cells

    Institute of Scientific and Technical Information of China (English)

    HAOFeng; YUJin-De

    2003-01-01

    AIM:To investigate the effects of high glucose on expression of matrix metalloproteinase-2(MMP-2) in rat aortic smooth muscle cells and the influence of matrix remodeling on atherogenesis in diabetic patients. METHODS: The smooth muscle cells were cultured from the thoracic aorta of Sprague-Dawley (SD) rat. MMP-2 mRNA was determined by reverse transcriptase-polymerase chain reaction(RT-PCR),MMP-2 protein was measured by Western blotting, and MMP-2 activity in conditioned medium was observed by zymography. RESULTS:In comparison with the control, there was no difference in the expression of MMP-2 when glucose concentration was 1g/L,whereas MMP-2 activity in smooth muscle cells was significantly increased by the glucose 5 g/L(P<0.01). CONCLUSION:High glucose enhanced the expression and activity of MMP-2 in smooth muscle cells, which may provide an explanation for the phenomenon that diabetes patients are prone to have atherosclerotic lesions.

  15. Imeglimin lowers glucose primarily by amplifying glucose-stimulated insulin secretion in high-fat-fed rodents

    DEFF Research Database (Denmark)

    Perry, Rachel J; Cardone, Rebecca L; Petersen, Max C

    2016-01-01

    insulin secretion in response to glucose during a hyperglycemic clamp after 1-wk of treatment in type 2 diabetic patients. However, whether the β-cell stimulatory effect of imeglimin is solely or partially responsible for its effects on glycemia remains to be fully confirmed. Here, we show that imeglimin......Imeglimin is a promising new oral antihyperglycemic agent that has been studied in clinical trials as a possible monotherapy or add-on therapy to lower fasting plasma glucose and improve hemoglobin A1c (1-3, 9). Imeglimin was shown to improve both fasting and postprandial glycemia and to increase...

  16. Effect of high glucose, angiotensin Ⅱ and receptor antagonist Losartan on the expression of connective tissue growth factor in cultured mesangial cells

    Institute of Scientific and Technical Information of China (English)

    黄颂敏; 刘芳; 沙朝晖; 付平; 杨一帆; 徐勇; 周海燕

    2003-01-01

    Objective To observe the effect of high glucose, angiotensin Ⅱ (AngⅡ) and Losartan on the expression of connective tissue growth factor (CTGF) mRNA in cultured mesangial cells (MCs). Methods MCs of SD rats were isolated and cultured. High glucose (30 mmol/L) and AngⅡ (10-9, 10 7, and 10-5 mol/L) were added to the medium for 72 hours to observe the influence on CTGF mRNA expression. Losartan of 10-5 mol/L and AngⅡ of 10-5 mol/L were added to the medium to observe the effects of Losartan on CTGF mRNA expression stimulated by AngⅡ. The expressions of CTGF mRNA were detected by reverse transcriptase polymerase chain reaction (RT-PCR).Results RT-PCR showed that high glucose and AngⅡ up-regulated the expression of CTGF mRNA, and AngⅡ stimulated the expression in a dose-dependent manner. Expression of CTGF mRNA induced by AngⅡwas partially suppressed by 10-5mol/L Losartan (P<0.05).Conclusions High glucose and AngⅡ can enhance the expression of CTGF mRNA and thus be involved in the process of renal fibrosis. Losartan can have a partial fibrogenesis-inhibiting effect, with implications for the treatment of renal fibrosis.

  17. Effects of sleep disruption and high fat intake on glucose metabolism in mice.

    Science.gov (United States)

    Ho, Jacqueline M; Barf, R Paulien; Opp, Mark R

    2016-06-01

    Poor sleep quality or quantity impairs glycemic control and increases risk of disease under chronic conditions. Recovery sleep may offset adverse metabolic outcomes of accumulated sleep debt, but the extent to which this occurs is unclear. We examined whether recovery sleep improves glucose metabolism in mice subjected to prolonged sleep disruption, and whether high fat intake during sleep disruption exacerbates glycemic control. Adult male C57BL/6J mice were subjected to 18-h sleep fragmentation daily for 9 days, followed by 1 day of recovery. During sleep disruption, one group of mice was fed a high-fat diet (HFD) while another group was fed standard laboratory chow. Insulin sensitivity and glucose tolerance were assessed by insulin and glucose tolerance testing at baseline, after 3 and 7 days of sleep disruption, and at the end of the protocol after 24h of undisturbed sleep opportunity (recovery). To characterize changes in sleep architecture that are associated with sleep debt and recovery, we quantified electroencephalogram (EEG) recordings during sleep fragmentation and recovery periods from an additional group of mice. We now report that 9 days of 18-h daily sleep fragmentation significantly reduces rapid eye movement sleep (REMS) and non-rapid eye movement sleep (NREMS). Mice respond with increases in REMS, but not NREMS, during the daily 6-h undisturbed sleep opportunity. However, both REMS and NREMS increase significantly during the 24-h