WorldWideScience

Sample records for inhibits high glucose-induced

  1. 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.

  2. 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.

  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. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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....

  14. 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

  15. 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.

  16. 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.

  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. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. Propofol protects against high glucose-induced endothelial adhesion molecules expression in human umbilical vein endothelial cells

    Directory of Open Access Journals (Sweden)

    Zhu Minmin

    2013-01-01

    Full Text Available Abstract Background Hyperglycemia could induce oxidative stress, activate transcription factor nuclear factor kappa B (NF-κB, up-regulate expression of endothelial adhesion molecules, and lead to endothelial injury. Studies have indicated that propofol could attenuate oxidative stress and suppress NF-κB activation in some situations. In the present study, we examined whether and how propofol improved high glucose-induced up-regulation of endothelial adhesion molecules in human umbilical vein endothelial cells (HUVECs. Methods Protein expression of endothelial adhesion molecules, NF-κB, inhibitory subunit of NF-κBα (IκBα, protein kinase Cβ2 (PKCβ2, and phosphorylation of PKCβ2 (Ser660 were measured by Western blot. NF-κB activity was measured by electrophoretic mobility shift assay. PKC activity was measured with SignaTECT PKC assay system. Superoxide anion (O2.- accumulation was measured with the reduction of ferricytochrome c assay. Human peripheral mononuclear cells were prepared with Histopaque-1077 solution. Results High glucose induced the expression of endothelial selectin (E-selectin, intercellular adhesion molecule 1 (ICAM-1, vascular cell adhesion molecule 1 (VCAM-1, and increased mononuclear-endothelial adhesion. High glucose induced O2.- accumulation, PKCβ2 phosphorylation and PKC activation. Further, high glucose decreased IκBα expression in cytoplasm, increased the translocation of NF-κB from cytoplasm to nuclear, and induced NF-κB activation. Importantly, we found these high glucose-mediated effects were attenuated by propofol pretreatment. Moreover, CGP53353, a selective PKCβ2 inhibitor, decreased high glucose-induced NF-κB activation, adhesion molecules expression, and mononuclear-endothelial adhesion. Conclusion Propofol, via decreasing O2.- accumulation, down-regulating PKCβ2 Ser660 phosphorylation and PKC as well as NF-κB activity, attenuated high glucose-induced endothelial adhesion molecules expression

  12. 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.

  13. 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.

  14. 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.

  15. Three pentacyclic triterpenes protect H9c2 cardiomyoblast cells against high-glucose-induced injury.

    Science.gov (United States)

    Chan, C Y; Mong, M C; Liu, W H; Huang, C Y; Yin, M C

    2014-04-01

    H9c2 cardiomyoblast cell line was used to examine the protection of three triterpenes, asiatic acid, boswellic acid, and oleanolic acid, at 5 or 10 μM against high-glucose-induced injury. High glucose stimulated reactive oxygen species (ROS), oxidized glutathione (GSSG), interleukin-6, tumor necrosis factor-alpha, and monocyte chemoattractant protein-1 production, as well as decreased glutathione peroxidase (GPX), glutathione reductase (GR) and catalase activities, and protein expression. However, pre-treatments of three triterpenes reserved glutathione, maintained activity and expression of GPX, GR, and catalase, as well as lowered ROS, GSSG, and inflammatory cytokines generation. High glucose reduced Na(+)-K(+)-ATPase activity, raised nuclear factor kappa (NF-κ) B and caspase-3 activities, up-regulated protein expression of NF-κB, mitogen-activated protein kinase, Bax, and cleaved caspase-3, as well as down-regulated Bcl-2 expression. Pre-treatments of three triterpenes retained Na(+)-K(+)-ATPase activity, declined NF-κB and caspase-3 activities, reserved Bcl-2 expression, as well as suppressed protein expression of NF-κB, p-p38, Bax, and cleaved caspase-3. These findings suggest that these triterpenes are potent cardiac-protective agents.

  16. 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.

  17. 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).

  18. Gallic Acid Decreases Inflammatory Cytokine Secretion Through Histone Acetyltransferase/Histone Deacetylase Regulation in High Glucose-Induced Human Monocytes.

    Science.gov (United States)

    Lee, Wooje; Lee, Sang Yeol; Son, Young-Jin; Yun, Jung-Mi

    2015-07-01

    Hyperglycemia contributes to diabetes and several diabetes-related complications. Gallic acid is a polyhydroxy phenolic compound found in various natural products. In this study, we investigated the effects and mechanism of gallic acid on proinflammatory cytokine secretion in high glucose-induced human monocytes (THP-1 cells). THP-1 cells were cultured under normoglycemic or hyperglycemic conditions, in the absence or presence of gallic acid. Hyperglycemic conditions significantly induced histone acetylation, nuclear factor-κB (NF-κB) activation, and proinflammatory cytokine release from THP-1 cells, whereas gallic acid suppressed NF-κB activity and cytokine release. It also significantly reduced CREB-binding protein/p300 (CBP/p300, a NF-κB coactivator) gene expression, acetylation levels, and CBP/p300 histone acetyltransferase (HAT) activity. In addition, histone deacetylase 2 (HDAC2) expression was significantly induced. These results suggest that gallic acid inhibits hyperglycemic-induced cytokine production in monocytes through epigenetic changes involving NF-κB. Therefore, gallic acid may have potential for the treatment and prevention of diabetes and its complications.

  19. 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.

  20. 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.

  1. 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.

  2. 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 .

  3. 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.

  4. Spleen tyrosine kinase mediates high glucose-induced transforming growth factor-{beta}1 up-regulation in proximal tubular epithelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Won Seok; Chang, Jai Won [Division of Nephrology, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, Seoul (Korea, Republic of); Han, Nam Jeong [Department of Cell Biology, Asan Institute for Life Sciences, Seoul (Korea, Republic of); Lee, Sang Koo [Division of Nephrology, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, Seoul (Korea, Republic of); Park, Su-Kil, E-mail: skpark@amc.seoul.kr [Division of Nephrology, Department of Internal Medicine, Asan Medical Center, College of Medicine, University of Ulsan, Seoul (Korea, Republic of)

    2012-09-10

    The role of spleen tyrosine kinase (Syk) in high glucose-induced intracellular signal transduction has yet to be elucidated. We investigated whether Syk is implicated in high glucose-induced transforming growth factor-{beta}1 (TGF-{beta}1) up-regulation in cultured human proximal tubular epithelial cells (HK-2 cell). High glucose increased TGF-{beta}1 gene expression through Syk, extracellular signal-regulated kinase (ERK), AP-1 and NF-{kappa}B. High glucose-induced AP-1 DNA binding activity was decreased by Syk inhibitors and U0126 (an ERK inhibitor). Syk inhibitors suppressed high glucose-induced ERK activation, whereas U0126 had no effect on Syk activation. High glucose-induced NF-{kappa}B DNA binding activity was also decreased by Syk inhibitors. High glucose increased nuclear translocation of p65 without serine phosphorylation of I{kappa}B{alpha} and without degradation of I{kappa}B{alpha}, but with an increase in tyrosine phosphorylation of I{kappa}B{alpha} that may account for the activation of NF-{kappa}B. Both Syk inhibitors and Syk-siRNA attenuated high glucose-induced I{kappa}B{alpha} tyrosine phosphorylation and p65 nuclear translocation. Depletion of p21-activated kinase 2 (Pak2) by transfection of Pak2-siRNA abolished high glucose-induced Syk activation. In summary, high glucose-induced TGF-{beta}1 gene transcription occurred through Pak2, Syk and subsequent ERK/AP-1 and NF-{kappa}B pathways. This suggests that Syk might be implicated in the diabetic kidney disease.

  5. Coenzyme Q10 Attenuates High Glucose-Induced Endothelial Progenitor Cell Dysfunction through AMP-Activated Protein Kinase Pathways

    Science.gov (United States)

    Tsai, Hsiao-Ya; Lin, Chih-Pei; Huang, Po-Hsun; Li, Szu-Yuan; Chen, Jia-Shiong; Lin, Feng-Yen; Chen, Jaw-Wen; Lin, Shing-Jong

    2016-01-01

    Coenzyme Q10 (CoQ10), an antiapoptosis enzyme, is stored in the mitochondria of cells. We investigated whether CoQ10 can attenuate high glucose-induced endothelial progenitor cell (EPC) apoptosis and clarified its mechanism. EPCs were incubated with normal glucose (5 mM) or high glucose (25 mM) enviroment for 3 days, followed by treatment with CoQ10 (10 μM) for 24 hr. Cell proliferation, nitric oxide (NO) production, and JC-1 assay were examined. The specific signal pathways of AMP-activated protein kinase (AMPK), eNOS/Akt, and heme oxygenase-1 (HO-1) were also assessed. High glucose reduced EPC functional activities, including proliferation and migration. Additionally, Akt/eNOS activity and NO production were downregulated in high glucose-stimulated EPCs. Administration of CoQ10 ameliorated high glucose-induced EPC apoptosis, including downregulation of caspase 3, upregulation of Bcl-2, and increase in mitochondrial membrane potential. Furthermore, treatment with CoQ10 reduced reactive oxygen species, enhanced eNOS/Akt activity, and increased HO-1 expression in high glucose-treated EPCs. These effects were negated by administration of AMPK inhibitor. Transplantation of CoQ10-treated EPCs under high glucose conditions into ischemic hindlimbs improved blood flow recovery. CoQ10 reduced high glucose-induced EPC apoptosis and dysfunction through upregulation of eNOS, HO-1 through the AMPK pathway. Our findings provide a potential treatment strategy targeting dysfunctional EPC in diabetic patients. PMID:26682233

  6. 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

  7. Naringin Protects Against High Glucose-Induced Human Endothelial Cell Injury Via Antioxidation and CX3CL1 Downregulation

    Directory of Open Access Journals (Sweden)

    Guilin Li

    2017-08-01

    Full Text Available Background/Aims: The induction of endothelial injury by hyperglycemia in diabetes has been widely accepted. Naringin is a bio-flavonoid. Some studies showed that naringin alleviates diabetic complications, but the exact mechanisms by which naringin improves diabetic anomalies are not yet fully understood. The aim of this research was to study the protective effect of naringin on high glucose-induced injury of human umbilical vein endothelial cells (HUVECs. Methods: HUVECs were cultured with or without high glucose in the absence or presence of naringin for 5 days. The expression of CX3CL1 was determined by quantitative real-time RT-PCR (qPCR and western blot. The cellular bioenergetic analysis oxygen consumption rate (OCR was measured with a Seahorse Bioscience XF analyzer. Results: The production of reactive oxygen species (ROS, the expression of CX3CL1 and the level of AKT phosphorylation were increased in HUVECs cultured with high glucose compared with controls. However, naringin rescued these increases in ROS production, CX3CL1 expression and AKT phosphorylation. Nitric oxide (NO production and OCR were lower in the high glucose group, and naringin restored the changes induced by high glucose. Molecular docking results suggested that Naringin might interact with the CX3CL1 protein. Conclusion: Naringin protects HUVECs from high-glucose-induced damage through its antioxidant properties by downregulating CX3CL1 and by improving mitochondrial function.

  8. Sanguis draconis, a dragon's blood resin, attenuates high glucose-induced oxidative stress and endothelial dysfunction in human umbilical vein endothelial cells.

    Science.gov (United States)

    Chang, Yi; Chang, Ting-Chen; Lee, Jie-Jen; Chang, Nen-Chung; Huang, Yung-Kai; Choy, Cheuk-Sing; Jayakumar, Thanasekaran

    2014-01-01

    Hyperglycaemia, a characteristic feature of diabetes mellitus, induces endothelial dysfunction and vascular complications by limiting the proliferative potential of these cells. Here we aimed to investigate the effect of an ethanolic extract of Sanguis draconis (SD), a kind of dragon's blood resin that is obtained from Daemonorops draco (Palmae), on human umbilical vein endothelial cells (HUVEC) under high-glucose (HG) stimulation and its underlying mechanism. Concentration-dependent (0-50 μg/mL) assessment of cell viability showed that SD does not affect cell viability with a similar trend up to 48 h. Remarkably, SD (10-50 μg/mL) significantly attenuated the high-glucose (25 and 50 mM) induced cell toxicity in a concentration-dependent manner. SD inhibited high glucose-induced nitrite (NO) and lipid peroxidation (MDA) production and reactive oxygen species (ROS) formation in HUVEC. Western blot analysis revealed that SD treatments abolished HG-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2), nuclear transcription factor, κB (NF-κB), VCAM-1, and E-selectin, and it also blocked the breakdown of PARP-116 kDa protein in a dose-dependent manner. Furthermore, we found that SD increased the expression of Bcl-2 and decreased Bax protein expression in HG-stimulated HUVEC. Thus, these results of this study demonstrate for the first time that SD inhibits glucose induced oxidative stress and vascular inflammation in HUVEC by inhibiting the ERK/NF-κB/PARP-1/Bax signaling cascade followed by suppressing the activation of VCAM-1 and E-selectin. These data suggest that SD may have a therapeutic potential in vascular inflammation due to the decreased levels of oxidative stress, apoptosis, and PARP-1 activation.

  9. Sanguis draconis, a Dragon’s Blood Resin, Attenuates High Glucose-Induced Oxidative Stress and Endothelial Dysfunction in Human Umbilical Vein Endothelial Cells

    Directory of Open Access Journals (Sweden)

    Yi Chang

    2014-01-01

    Full Text Available Hyperglycaemia, a characteristic feature of diabetes mellitus, induces endothelial dysfunction and vascular complications by limiting the proliferative potential of these cells. Here we aimed to investigate the effect of an ethanolic extract of Sanguis draconis (SD, a kind of dragon’s blood resin that is obtained from Daemonorops draco (Palmae, on human umbilical vein endothelial cells (HUVEC under high-glucose (HG stimulation and its underlying mechanism. Concentration-dependent (0–50 μg/mL assessment of cell viability showed that SD does not affect cell viability with a similar trend up to 48 h. Remarkably, SD (10–50 μg/mL significantly attenuated the high-glucose (25 and 50 mM induced cell toxicity in a concentration-dependent manner. SD inhibited high glucose-induced nitrite (NO and lipid peroxidation (MDA production and reactive oxygen species (ROS formation in HUVEC. Western blot analysis revealed that SD treatments abolished HG-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK 1/2, nuclear transcription factor, κB (NF-κB, VCAM-1, and E-selectin, and it also blocked the breakdown of PARP-116 kDa protein in a dose-dependent manner. Furthermore, we found that SD increased the expression of Bcl-2 and decreased Bax protein expression in HG-stimulated HUVEC. Thus, these results of this study demonstrate for the first time that SD inhibits glucose induced oxidative stress and vascular inflammation in HUVEC by inhibiting the ERK/NF-κB/PARP-1/Bax signaling cascade followed by suppressing the activation of VCAM-1 and E-selectin. These data suggest that SD may have a therapeutic potential in vascular inflammation due to the decreased levels of oxidative stress, apoptosis, and PARP-1 activation.

  10. MicroRNA-34a regulates high glucose-induced apoptosis in H9c2 cardiomyocytes.

    Science.gov (United States)

    Zhao, Fang; Li, Bo; Wei, Yin-zhi; Zhou, Bin; Wang, Han; Chen, Ming; Gan, Xue-dong; Wang, Zhao-hui; Xiong, Shi-xi

    2013-12-01

    Hyperglycemia is an important initiator of cardiovascular disease, contributing to the development of cardiomyocyte death and diabetic complications. The purpose of the present study was to investigate whether high glucose state could induce apoptosis of rat cardiomyocyte cell line H9c2 through microRNA-mediated Bcl-2 signaling pathway. The expression of miR-34a and Bcl-2 mRNA was detected by using real-time PCR. Western blotting was used to examine the changes in apoptosis-associated protein Bcl-2. Apoptosis of H9c2 cells was tested by using flow cytometry. The results showed that the expression of miR-34a was significantly elevated and that of Bcl-2 was strongly reduced, and apoptosis of cardiomyocytes was apparently increased in the high-glucose-treated H9c2 cells as compared with normal-glucose-treated controls. In addition, we identified Bcl-2 gene was the target of miR-34a. miR-34a mimics reduced the expression of Bcl-2 and increased glucose-induced apoptosis, but miR-34a inhibitor acted as the opposite mediator. Our data demonstrate that miR-34a contributes to high glucose-induced decreases in Bcl-2 expression and subsequent cardiomyocyte apoptosis.

  11. 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

  12. Sequential signaling cascade of IL-6 and PGC-1α is involved in high glucose-induced podocyte loss and growth arrest

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Dong Il; Park, Soo Hyun, E-mail: parksh@chonnam.ac.kr

    2013-06-14

    Highlights: •The pathophysiological role of IL-6 in high glucose-induced podocyte loss. •The novel role of PGC-1α in the development of diabetic nephropathy. •Signaling of IL-6 and PGC-1α in high glucose-induced dysfunction of podocyte. -- Abstract: Podocyte loss, which is mediated by podocyte apoptosis, is implicated in the onset of diabetic nephropathy. In this study, we investigated the involvement of interleukin (IL)-6 in high glucose-induced apoptosis of rat podocytes. We also examined the pathophysiological role of peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) in this system. High glucose treatment induced not only podocyte apoptosis but also podocyte growth arrest. High glucose treatment also increased IL-6 secretion and activated IL-6 signaling. The high glucose-induced podocyte apoptosis was blocked by IL-6 neutralizing antibody. IL-6 treatment or overexpression induced podocyte apoptosis and growth arrest, and IL-6 siRNA transfection blocked high glucose-induced podocyte apoptosis and growth arrest. Furthermore, high glucose or IL-6 treatment increased PGC-1α expression, and PGC-1α overexpression also induced podocyte apoptosis and growth arrest. PGC-1α siRNA transfection blocked high glucose-induced podocyte apoptosis and growth arrest. Collectively, these findings showed that high glucose promoted apoptosis and cell growth arrest in podocytes via IL-6 signaling. In addition, PGC-1α is involved in podocyte apoptosis and cell growth arrest. Therefore, blocking IL-6 and its downstream mediators such as IL6Rα, gp130 and PGC-1α may attenuate the progression of diabetic nephropathy.

  13. iNOS-derived peroxynitrite mediates high glucose-induced inflammatory gene expression in vascular smooth muscle cells through promoting KLF5 expression and nitration.

    Science.gov (United States)

    Zhang, Man-Li; Zheng, Bin; Tong, Fei; Yang, Zhan; Wang, Zhi-Bo; Yang, Bao-Ming; Sun, Yan; Zhang, Xin-Hua; Zhao, Yi-Lin; Wen, Jin-Kun

    2017-07-12

    Inducible NO synthase (iNOS) expression and peroxynitrite formation are significantly increased in diabetic vascular tissues. Transcription factor KLF5 activates iNOS gene transcription and is involved in vascular inflammatory injury and remodeling. However, mutual regulation between KLF5, iNOS and peroxynitrite in diabetic vascular inflammation, as well as the underlying mechanisms, remain largely unknown. In this study, we found a marked increase in KLF5 and iNOS expression in vascular smooth muscle cells (VSMC) of diabetic patients. High glucose-induced expression of KLF5 and iNOS was also observed in cultured mouse VSMCs. Further investigation showed that high glucose induced KLF5 nitration by iNOS-mediated peroxynitrite generation, and nitrated KLF5 increased its interaction with NF-κB p50 and thus cooperatively activated the expression of inflammatory cytokines TNF-α and IL-1β. Furthermore, we showed that the VSMC-specific knockout of KLF5 dramatically reduced inflammatory cytokine expression in the vascular tissues of diabetic mice. Moreover, 17β-estradiol (E2) inhibited high glucose-mediated effects in VSMCs, and in the response to E2, estrogen receptor (ER) α competed with KLF5 for binding to NF-κB p50, which in turn leads to the suppression of inflammatory gene expression in VSMCs. Together, the present findings were the first to show that KLF5 expression and nitration by iNOS-mediated peroxynitrite are necessary for the induction of TNF-α and IL-1β expression in VSMCs of diabetic vascular tissues. Copyright © 2017. Published by Elsevier B.V.

  14. 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

  15. 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.

  16. Glucose-induced thermogenesis in patients with small cell lung carcinoma. Before and after inhibition of tumour growth by chemotherapy

    DEFF Research Database (Denmark)

    Simonsen, L; Bülow, J; Sengeløv, H

    1993-01-01

    Seven weight-losing patients with histologically verified small cell lung carcinoma were given an oral glucose load of 75 g before and at least 3 weeks after the end of chemotherapy to examine the effect of glucose on whole body and skeletal muscle thermogenesis before and after reduction of tumour....... 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 skeletal muscle was calculated as the product of the forearm blood flow and the difference in a-v oxygen...... concentration. Whole body resting energy expenditure (REE) did not increase, it was 4.4 +/- 0.3 kJ min-1 (mean +/- SE) before chemotherapy and 4.4 +/- 0.2 kJ min-1 after chemotherapy. The glucose-induced thermogenesis in the 180 min following the glucose load was 93.6 +/- 9.9 kJ 180 min-1 before chemotherapy...

  17. 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.

  18. 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.

  19. 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.

  20. VDR Activation Reduces Proteinuria and High-Glucose-Induced Injury of Kidneys and Podocytes by Regulating Wnt Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Jia Guo

    2017-08-01

    Full Text Available Background: Diabetic nephropathy (DN is a major cause of end-stage renal disease and proteinuria is one of the most prominent clinical manifestations. The expression of Vitamin D receptor (VDR in patients with chronic kidney diseases was decreased, while VDR agonists could partially alleviate the proteinuria of DN in animal models. The present study was designed to determine the expression of VDR in renal tissues and its relationship with proteinuria the diabetic model db/db mice. Methods: The regulation effects of VDR on the Wnt signaling pathway were analyzed using RNA interference and VDR agonist paricalcitol. Results: With the increase in age of the db/db mice, the VDR protein and mRNA levels in renal tissues were decreased, proteinuria increased, and the protein and mRNA levels of GSK-3β of and β-catenin increased. Paricalcitol treatment resulted in the up-regulation of VDR and down-regulation of GSK-3β and β-catenin, indicating that VDR had a regulatory effect on the Wnt signaling pathway. Conclusion: VDR activation could reduce proteinuria of DN mice and alleviate high-glucose-induced injury of kidneys and podocytes by regulating the key molecules of Wnt signaling pathway.

  1. 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.

  2. 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.

  3. 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.

  4. High glucose induced oxidative stress and apoptosis in cardiac microvascular endothelial cells are regulated by FoxO3a.

    Directory of Open Access Journals (Sweden)

    Chaoming Peng

    Full Text Available AIM: Cardiac microvascular endothelial cells (CMECs dysfunction contributes to cardiovascular complications in diabetes, whereas, the underlying mechanism is not fully clarified. FoxO transcription factors are involved in apoptosis and reactive oxygen species (ROS production. Therefore, the present study was designed to elucidate the potential role of FoxO3a on the CMECs injury induced by high glucose. MATERIALS AND METHODS: CMECs were isolated from hearts of adult rats and cultured in normal or high glucose medium for 6 h, 12 h and 24 h respectively. To down-regulate FoxO3a expression, CMECs were transfected with FoxO3a siRNA. ROS accumulation and apoptosis in CMECs were assessed by dihydroethidine (DHE staining and TUNEL assay respectively. Moreover, the expressions of Akt, FoxO3a, Bim and BclxL in CMECs were assessed by Western blotting assay. RESULTS: ROS accumulation in CMECs was significantly increased after high glucose incubation for 6 to 24 h. Meanwhile, high glucose also increased apoptosis in CMECs, correlated with decreased the phosphorylation expressions of Akt and FoxO3a. Moreover, high glucose incubation increased the expression of Bim, whereas increased anti-apoptotic protein BclxL. Furthermore, siRNA target FoxO3a silencing enhanced the ROS accumulation, whereas suppressed apoptosis in CMECs. FoxO3a silencing also abolished the disturbance of Bcl-2 proteins induced by high glucose in CMECs. CONCLUSION: Our data provide evidence that high glucose induced FoxO3a activation which suppressed ROS accumulation, and in parallel, resulted in apoptosis of CMECs.

  5. 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.

  6. Zerumbone ameliorates high glucose-induced reduction in AMPK phosphorylation in tubular kidney cells.

    Science.gov (United States)

    Shrikant, Chomanahalli B; Chilkunda, Nandini D

    2017-10-03

    AMP-activated protein kinase (AMPK) plays an important role in pathophysiology of diabetes and its complications. In recent years, its role in kidney as a therapeutic target in ameliorating diabetic kidney damage is receiving renewed attention. Efforts on identifying AMPK modulators from dietary sources have gained prominence because of the tremendous potential it harbours. We therefore, examined the effect of a few bioactives on AMPK phosphorylation in kidney tubular cells. AMPK phosphorylation at Thr172 was reduced (0.42 ± 0.05 - fold change compared to control; p<0.01 vs. control) after treatment with high glucose (30 mM) for 48 h and restored by zerumbone (1.59 ± 0.20; p<0.01 vs. high glucose) but not by other tested modulators. Zerumbone also increased the phosphorylation of downstream target of AMPK, the acetyl-CoA carboxylase (ACC) without affecting the mitochondrial membrane potential and ADP/ATP ratio. Thus, zerumbone could potentially be explored as a therapeutic agent in bringing about energy homeostasis in diabetes where high glucose suppresses AMPK pathway.

  7. Mechanisms of action of troglitazone in the prevention of high glucose-induced migration and proliferation of cultured coronary smooth muscle cells.

    Science.gov (United States)

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

    1997-12-01

    Recent findings suggest that high glucose levels may promote atherosclerosis in coronary vascular smooth muscle cells (VSMCs). To explore the intracellular mechanisms of action by which troglitazone affects this process, we examined the effect of troglitazone on the migration and growth characteristics of cultured rabbit coronary VSMCs. Treatment with chronic high glucose medium (22.2 mmol/L) for 5 days increased VSMC migration by 92%, [3H]thymidine incorporation by 135%, and cell number by 32% compared with VSMCs treated with normal glucose (5.5 mmol/L glucose + 16.6 mmol/L mannose) medium. Trolitazone at 100 nmol/L and 1 mumol/L significantly suppressed high glucose-induced VSMC migration by 34% and 42%, respectively, the proliferative effect (as measured by cell number) by 17% and 27%, and [3H]thymidine incorporation by 45% and 60% (n = 6, P < .05). The high glucose-induced impairment of insulin-mediated [3H]deoxyglucose uptake was blocked by a protein kinase C (PKC) inhibitor (calphostin C, 1 mumol/L) and was also improved by troglitazone without any change in insulin receptor number and affinity. The high glucose-induced insulin-mediated increase in cell number and in [3H]thymidine incorporation was suppressed by troglitazone. Troglitazone (1 mumol/L) also suppressed high glucose-induced phospholipase D activation, elevation of the cytosolic NADH/NAD+ ratio (as measured by the cytosolic ratio of lactate/pyruvate), and membrane-bound PKC activation. Flow cytometric DNA histogram analysis of cell cycle stage showed that high glucose-induced increase in the percentage of cells in the S phase was suppressed by 1 mumol/L troglitazone. These findings suggest that PKC may be a link between impairment of insulin-mediated glucose uptake and the increase in migration and proliferation induced by high glucose levels and that troglitazone may be clinically useful for the treatment of high glucose-induced coronary atherosclerosis.

  8. High glucose induces dysfunction of airway epithelial barrier through down-regulation of connexin 43.

    Science.gov (United States)

    Yu, Hongmei; Yang, Juan; Zhou, Xiangdong; Xiao, Qian; Lü, Yang; Xia, Li

    2016-03-01

    The airway epithelium is a barrier to the inhaled antigens and pathogens. Connexin 43 (Cx43) has been found to play critical role in maintaining the function of airway epithelial barrier and be involved in the pathogenesis of the diabetic retinal vasculature, diabetes nephropathy and diabetes skin. Hyperglycemia has been shown to be an independent risk factor for respiratory infections. We hypothesize that the down-regulation of Cx43 induced by HG alters the expression of tight junctions (zonula occludens-1 (ZO-1) and occludin) and contributes to dysfunction of airway epithelial barrier, and Cx43 plays a critical role in the process in human airway epithelial cells (16 HBE). We show that high glucose (HG) decreased the expression of ZO-1 and occludin, disassociated interaction between Cx43 and tight junctions, and then increased airway epithelial transepithelial electrical resistance (TER) and permeability by down-regulation of Cx43 in human airway epithelial cells. These observations demonstrate an important role for Cx43 in regulating HG-induced dysfunction of airway epithelial barrier. These findings may bring new insights into the molecular pathogenesis of pulmonary infection related to diabetes mellitus and lead to novel therapeutic intervention for the dysfunction of airway epithelial barrier in chronic inflammatory airway diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  9. The PI3K/Akt Signaling Pathway Mediates the High Glucose-Induced Expression of Extracellular Matrix Molecules in Human Retinal Pigment Epithelial Cells

    Directory of Open Access Journals (Sweden)

    Dong Qin

    2015-01-01

    Full Text Available Prolonged hyperglycemia is an important risk factor of the pathogenesis of diabetic retinopathy (DR. Extracellular matrix molecules, such as fibronectin, collagen IV, and laminin, are associated with fibrotic membranes. In this study, we investigated the expression of fibronectin, collagen IV, and laminin in RPE cells under high glucose conditions. Furthermore, we also detected the phosphorylation of protein kinase B (Akt under high glucose conditions in RPE cells. Our results showed that high glucose upregulated fibronectin, collagen IV, and laminin expression, and activated Akt in RPE cells. We also found that pretreatment with LY294002 (an inhibitor of phosphatidylinositol 3-kinase abolished high glucose-induced expression of fibronectin, collagen IV, and laminin in RPE cells. Thus, high glucose induced the expression of fibronectin, collagen IV, and laminin through PI3K/Akt signaling pathway in RPE cells, and the PI3K/Akt signaling pathway may contribute to the formation of fibrotic membrane during the development of DR.

  10. 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.

  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. Role of salt inducible kinase 1 in high glucose-induced lipid accumulation in HepG2 cells and metformin intervention.

    Science.gov (United States)

    Zhang, Yue; Takemori, Hiroshi; Wang, Chang; Fu, JiaHui; Xu, MingWang; Xiong, Liang; Li, NingXu; Wen, XiuYing

    2017-03-15

    To investigate the roles of salt inducible kinase (SIK1) in high glucose-induced triglyceride accumulation in human hepatoma HepG2 cells as well as in the molecular mechanism by which metformin, a drug to treat diabetes, suppresses high glucose-induced lipogenesis. A cell model for high glucose-induced hepatic steatosis was prepared by exposing HepG2 cells to high glucose (25mmol) in the absence or presence of metformin (0.5mmol). Intracellular triglycerides were visualized by Oil Red O and measured using a triglyceride assay kit. Cell viability was evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide method. SIK1 overexpression in HepG2 cells was achieved by transient transfection, and the mRNA and protein levels of SIK1 and lipogenic factors were measured using a reverse transcription-polymerase chain reaction and western blotting, respectively. Lipid accumulation in HepG2 cells was obvious after treatment with high glucose for 24h. In response to high glucose, SIK1 expression was negatively correlated with that of lipogenic factors and lipid accumulation in HepG2 cells. We observed that overexpression of SIK1, or treatment with metformin, suppressed lipogenesis, even in high glucose conditions. Furthermore, treatment with metformin upregulated SIK1 mRNA and protein levels, as well as the active form of SIK1. SIK1 plays a vital role in high glucose-induced lipid accumulation, and metformin suppresses lipogenesis via the induction and activation of SIK1. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. High glucose induced alteration of SIRTs in endothelial cells causes rapid aging in a p300 and FOXO regulated pathway.

    Directory of Open Access Journals (Sweden)

    Rokhsana Mortuza

    Full Text Available In diabetes, some of the cellular changes are similar to aging. We hypothesized that hyperglycemia accelerates aging-like changes in the endothelial cells (ECs and tissues leading to structural and functional damage. We investigated glucose-induced aging in 3 types of ECs using senescence associated β-gal (SA β-gal staining and cell morphology. Alterations of sirtuins (SIRTs and their downstream mediator FOXO and oxidative stress were investigated. Relationship of such alteration with histone acetylase (HAT p300 was examined. Similar examinations were performed in tissues of diabetic animals. ECs in high glucose (HG showed evidence of early senescence as demonstrated by increased SA β-gal positivity and reduced replicative capacities. These alterations were pronounced in microvascular ECs. They developed an irregular and hypertrophic phenotype. Such changes were associated with decreased SIRT (1-7 mRNA expressions. We also found that p300 and SIRT1 regulate each other in such process, as silencing one led to increase of the others' expression. Furthermore, HG caused reduction in FOXO1's DNA binding ability and antioxidant target gene expressions. Chemically induced increased SIRT1 activity and p300 knockdown corrected these abnormalities slowing aging-like changes. Diabetic animals showed increased cellular senescence in renal glomerulus and retinal blood vessels along with reduced SIRT1 mRNA expressions in these tissues. Data from this study demonstrated that hyperglycemia accelerates aging-like process in the vascular ECs and such process is mediated via downregulation of SIRT1, causing reduction of mitochondrial antioxidant enzyme in a p300 and FOXO1 mediated pathway.

  14. High glucose induces activation of NF-κB inflammatory signaling through IκBα sumoylation in rat mesangial cells

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Wei [Department of Endocrinology, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan 646000 (China); Department of Endocrinology, The People’s Hospital of Xindu, Xindu, Sichuang, 610500 (China); Xu, Ling [Department of Endocrinology, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan 646000 (China); Zhou, Xueqin [Department of Endocrinology, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan 646000 (China); Department of Endocrinology, The People’s Hospital of Leshan, Sichuang (China); Gao, Chenlin; Yang, Maojun; Chen, Guo; Zhu, Jianhua; Jiang, Lan [Department of Endocrinology, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan 646000 (China); Gan, Huakui [Department of Endocrinology, The First Hospital of NeiJiang, Sichuang (China); Gou, Fang; Feng, Hong; Peng, Juan [Department of Endocrinology, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan 646000 (China); Xu, Yong, E-mail: xywyll@aliyun.com [Department of Endocrinology, Affiliated Hospital of Luzhou Medical College, Luzhou, Sichuan 646000 (China)

    2013-08-30

    Highlights: •The expression of SUMO1, SUMO2/3 under high glucose was obviously enhanced. •High glucose induced degradation of IκBα and activation of NF-κB pathway. •Sumoylation of IκBα in high glucose were significantly decreased. •The proteasome inhibitor MG132 could partially revert the degradation of IκBα. -- Abstract: The posttranslational modification of proteins by small ubiquitin-like modifiers (SUMOs) has emerged as an important regulatory mechanism for the alteration of protein activity, stability, and cellular localization. The latest research demonstrates that sumoylation is extensively involved in the regulation of the nuclear factor κB (NF-κB) pathway, which plays a critical role in the regulation of inflammation and contributes to fibrosis in diabetic nephropathy (DN). However, the role of sumoylation in the regulation of NF-κB signaling in DN is still unclear. In the present study, we cultured rat glomerular mesangial cells (GMCs) stimulated by high glucose and divided GMCs into six groups: normal glucose group (5.6 mmol/L), high glucose groups (10, 20, and 30 mmol/L), mannitol group (i.e., osmotic control group), and MG132 intervention group (30 mmol/L glucose with MG132, a proteasome inhibitor). The expression of SUMO1, SUMO2/3, IκBα, NF-κBp65, and monocyte chemotactic protein 1 (MCP-1) was measured by Western blot, reverse-transcription polymerase chain reaction, and indirect immunofluorescence laser scanning confocal microscopy. The interaction between SUMO1, SUMO2/3, and IκBα was observed by co-immunoprecipitation. The results showed that the expression of SUMO1 and SUMO2/3 was dose- and time-dependently enhanced by high glucose (p < 0.05). However, the expression of IκBα sumoylation in high glucose was significantly decreased compared with the normal glucose group (p < 0.05). The expression of IκBα was dose- and time-dependently decreased, and NF-κBp65 and MCP-1 were increased under high glucose conditions, which

  15. The dual targeting of EGFR and ErbB2 with the inhibitor Lapatinib corrects high glucose-induced apoptosis and vascular dysfunction by opposing multiple diabetes-induced signaling changes.

    Science.gov (United States)

    Benter, Ibrahim F; Sarkhou, Fatima; Al-Khaldi, Abeer T; Chandrasekhar, Bindu; Attur, Sreeja; Dhaunsi, Gursev S; Yousif, Mariam H M; Akhtar, Saghir

    2015-01-01

    The epidermal growth factor receptors, EGFR and EGFR2 (ErbB2), appear important mediators of diabetes-induced vascular dysfunction. We investigated whether targeted dual inhibition of EGFR and ErbB2 with Lapatinib would be effective in treating diabetes-induced vascular dysfunction in a rat model of type 1 diabetes. In streptozotocin-induced diabetes, chronic 4-week oral or acute, ex vivo, administration of Lapatinib prevented the development of vascular dysfunction as indicated by the attenuation of the hyper-reactivity of the diabetic mesenteric vascular bed (MVB) to norephinephrine without correcting hyperglycemia. Chronic in vivo or acute ex vivo Lapatinib treatment also significantly attenuated diabetes-induced increases in phosphorylation of EGFR, ErbB2, ERK1/2, AKT, ROCK2 and IkB-alpha as well as normalized the reduced levels of phosphorylated FOXO3A, and eNOS (Ser1177) in the diabetic MVB. Similar results were observed in vascular smooth muscle cells (VSMCs) cultured in high glucose (25 mM) treated with Lapatinib or small interfering RNA (siRNA) targeting the ErbB2 receptor. Lapatinib also prevented high glucose-induced apoptosis in VSMC. Thus, Lapatinib corrects hyperglycemia-induced apoptosis and vascular dysfunction with concomitant reversal of diabetes or high glucose-induced signaling changes in EGFR/ErbB2 and downstream signaling pathways implying that targeted dual inhibition of EGFR/ErbB2 might be an effective vasculoprotective treatment strategy in diabetic patients.

  16. Linagliptin Limits High Glucose Induced Conversion of Latent to Active TGFß through Interaction with CIM6PR and Limits Renal Tubulointerstitial Fibronectin.

    Directory of Open Access Journals (Sweden)

    Muralikrishna Gangadharan Komala

    Full Text Available In addition to lowering blood glucose in patients with type 2 diabetes mellitus, dipeptidyl peptidase 4 (DPP4 inhibitors have been shown to be antifibrotic. We have previously shown that cation independent mannose-6-phosphate receptor (CIM6PR facilitates the conversion of latent to active transforming growth factor β1 (GFß1 in renal proximal tubular cells (PTCs and linagliptin (a DPP4 inhibitor reduced this conversion with downstream reduction in fibronectin transcription.We wanted to demonstrate that linagliptin reduces high glucose induced interaction between membrane bound DPP4 and CIM6PR in vitro and demonstrate reduction in active TGFß mediated downstream effects in a rodent model of type 1 diabetic nephropathy independent of high glycaemic levels.We used human kidney 2 (HK2 cells and endothelial nitric oxide synthase knock out mice to explore the mechanism and antifibrotic potential of linagliptin independent of glucose lowering. Using a proximity ligation assay, we show that CIM6PR and DPP4 interaction was increased by high glucose and reduced by linagliptin and excess mannose-6-phosphate (M6P confirming that linagliptin is operating through an M6P-dependent mechanism. In vivo studies confirmed these TGFß1 pathway related changes and showed reduced fibronectin, phosphorylated smad2 and phosphorylated smad2/3 (pSmad2/3 with an associated trend towards reduction in tubular atrophy, which was independent of glucose lowering. No reduction in albuminuria, glomerulosclerotic index or cortical collagen deposition was observed.Linagliptin inhibits activation of TGFß1 through a M6P dependent mechanism. However this in isolation is not sufficient to reverse the multifactorial nature of diabetic nephropathy.

  17. 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

  18. Glucose-induced binding of the polypyrimidine tract-binding protein (PTB) to the 3'-untranslated region of the insulin mRNA (ins-PRS) is inhibited by rapamycin.

    Science.gov (United States)

    Tillmar, Linda; Welsh, Nils

    2004-05-01

    Despite considerable knowledge on the regulation of insulin gene transcription, little is known about the post-transcriptional control mechanisms of this gene. We have recently reported glucose- and hypoxia-regulated binding of the polypyrimidine tract-binding protein (PTB) to the pyrimidine-rich sequence of the 3'-untranslated insulin mRNA (ins-PRS), an event which may control insulin mRNA stability. The present aim was to probe for the signaling pathways that control this binding activity. Rat islets were exposed to pharmacological inhibitors against several molecules, previously shown to be involved in glucose signaling. The inhibitors used were; LY 294002 (PI3 kinase), Rp-cAMP triatylamine (the cAMP-dependent protein kinase PKA), bisindolylmaleimide I hydrochloride (PKC), PD 098059 (ERK1/ERK2), SB 203580 (p38/SAPK2a), rapamycin (mTOR) and okadaic acid (PP1/2A). PTB-binding activity to the ins-PRS was then analyzed by elecrophoretic mobility shift assay (EMSA). The glucose-induced PTB-binding was only inhibited by the mTOR inhibitor rapamycin. Rapamycin also reduced glucose-induced insulin mRNA expression. Thus, our results suggest an involvement of mTOR in glucose-induced PTB/ins-PRS binding and insulin mRNA stability.

  19. 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

  20. 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.

  1. [Salidroside attenuates high glucose-induced apoptosis in human umbilical vein endothelial cells via activating the Ca(2)+/CaM/CAMKIIδ/eNOS pathway].

    Science.gov (United States)

    Chen, Ziwei; Wu, Xiang

    2014-04-01

    Endothelial oxidative stress plays an important role in the pathogenesis of cardiovascular disease. Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L, could exert potent antioxidant properties. In this study, we investigated the protective effects, and related mechanism of salidroside against high glucose (33 mmol/L)-induced cell damage in human umbilical vein endothelial cells (HUVECs). HUVECs were cultured in normal glucose (5.5 mmol/L), high glucose (33 mmol/L), high salidroside (10 µg/ml+33 mmol/L glucose), moderate salidroside (4 µg/ml+33 mmol/L glucose), low salidroside (1 µg/ml+33 mmol/L glucose) and very low salidroside (0.1 µg/ml+33 mmol/L glucose) for 48 h. Cell viability, the level of malondialdehyde (MDA) , reactive oxygen species (ROS) , nitric oxide (NO) , [Ca(2)+]i, calmodulin (CaM) , calmodulin-dependent kinase (CaMK) IIδ, endothelial nitric oxide synthase (eNOS) , active caspase-3 protein expression and eNOS ser 1177 phosphorylation of HUVECs post various treatments were measured. The cell viability was assessed with MTT assay, and the level of ROS, and [Ca(2)+]i was analyzed using flow cytometry. Nitric oxide and MDA was detected by Nitric Oxide Assay Kit and MDA Assay Kit. Western blot was performed to detect the protein expressions of eNOS, active caspase-3 and eNOS ser 1177 phosphorylation. Comparing to the normal glucose group, high glucose treatment increased the cell damage, the level of NO and [Ca(2)+]i (P Salidroside treatment significantly attenuated high glucose-induce cell damage on cultured HUVECs in a dose-dependent manner. Comparing to the high glucose group, 10 µg/ml Salidroside significantly increased cell viability (P salidroside could attenuate high glucose induced apoptosis in HUVEC, partly through activating the Ca(2)+/CaM/CAMKIIδ/eNOS pathway.

  2. The pivotal role of high glucose-induced overexpression of PKCβ in the appearance of glucagon-like peptide-1 resistance in endothelial cells.

    Science.gov (United States)

    Pujadas, Gemma; De Nigris, Valeria; La Sala, Lucia; Testa, Roberto; Genovese, Stefano; Ceriello, Antonio

    2016-11-01

    Recently, it has been demonstrated that Glucagon-like peptide-1 (GLP-1) has a protective effect on endothelial cells. Our hypothesis is that this GLP-1 protective effect is partly lost when the cells are exposed to sustained high glucose concentrations. Human umbilical vein endothelial cells (HUVECs) were cultured for 21 days in normal glucose (5 mmol/L, NG) or high glucose (25 mmol/L glucose, HG). GLP-1 (7-37) and Ruboxistaurin were added at 50 and 500 nM, respectively, alone or in combination, 1 h before cell harvesting. Analysis of GLP-1 receptor protein levels, as well as of the gene expression of different ER stress-related genes, proliferation markers, antioxidant cell response-related genes, and PKA subunits, was performed. ROS production was also measured in HUVECs exposed to mentioned treatments. GLP-1 receptor expression was reduced in HUVECs exposed to chronic high glucose concentrations but was partially restored by a chemical PKCβ-specific inhibitor. GLP-1, added as an acute treatment in endothelial cells, had the capacity to induce the expression of Nrf2-detoxifying enzyme targets, to increase transcription levels of scavenger genes, to attenuate the expression of high glucose-induced PKA subunits, ER stress and also the apoptotic phenotype of HUVECs; these effects occured only when high glucose-induced PKCβ overexpression was reduced by Ruboxistaurin. In a similar manner, ROS production induced by high glucose was reduced by GLP-1 in the presence of PKCβ inhibitor. This study suggests that an increase in PKCβ, induced by high glucose, could have a role in endothelial GLP-1 resistance, reducing GLP-1 receptor levels and disrupting the GLP-1 canonical pathway.

  3. Epigallocatechin-3-gallate combined with alpha lipoic acid attenuates high glucose-induced receptor for advanced glycation end products (RAGE expression in human embryonic kidney cells

    Directory of Open Access Journals (Sweden)

    Jyh-Gang Leu

    Full Text Available The anti-oxidant effects of epigallocatechin gallate (EGCG and alpha lipoic acid (ALA have been demonstrated in previous studies. The kidney protection effects of EGCG and ALA in patients with kidney injury are still under investigation. The purpose of this study is to investigate the anti-inflammatory and anti-oxidant effects of EGCG and ALA on high glucose-induced human kidney cell damage. EGCG inhibited high glucose(HG-induced TNF-α and IL-6 production in human embryonic kidney (HEK cells. Both EGCG and ALA decreased HG-induced receptor of advanced glycation end products (RAGE mRNA and protein expressions in HEK cells. EGCG and ALA also recovered HG-inhibited superoxide dismutase production and decreased ROS expressions in HEK cells. The synergism of EGCG and ALA was also studied. The effect of EGCG combined with ALA is greater than the effect of EGCG alone in all anti-inflammation and anti-oxidant experiments. Our studies provide a potential therapeutic application of EGCG and ALA in preventing progression of diabetic nephropathy.Os efeitos antioxidantes de galato de epigalocatequina (EGCG e ácido alfa lipóico (ALA foram demonstrados em estudos anteriores. Os efeitos renais da proteção de EGCG e ALA em pacientes com lesão renal ainda estão sob investigação. A finalidade deste estudo é investigar os efeitos anti-inflamatórios e antioxidantes de EGCG e ALA em lesão de células de rim humano induzida pela alta glicose. EGCG inibiu a produção de TNF-α e IL-6 induzida por HG em células de rim embrionário humano (HEK. Ambos EGCG e ALA diminuíram o mRNA do receptor de produtos finais de glicação avançada (RAGE induzida por HG e a expressão de proteínas em células HEK. EGCG e ALA também recuperaram a produção de superóxido dismutase inibida por HG e diminuíram a expressão de ROS em células HEK. O sinergismo de EGCG e ALA também foi estudado. O efeito de EGCG combinado com ALA é maior do que o efeito de EGCG sozinho

  4. Protective effect of hydrogen-rich medium against high glucose-induced apoptosis of Schwann cells in vitro.

    Science.gov (United States)

    Yu, Yang; Ma, Xiaoye; Yang, Tao; Li, Bo; Xie, Keliang; Liu, Daquan; Wang, Guolin; Yu, Yonghao

    2015-09-01

    Diabetic peripheral neuropathy (DPN) is considered to be one of the most prevalent and life threatening microvascular diabetic complications. DPN affects up to 50% of patients with diabetes mellitus and there are currently no efficacious therapeutic strategies available for its treatment. Previous studies have reported that oxidative stress and poly(ADP‑ribose) polymerase‑1 (PARP‑1) may be unifying factors for hyperglycemic injury. The aim of the present study was to investigate the protective effects of hydrogen‑rich medium (HM) on high glucose (HG)‑mediated oxidative stress, PARP‑1 activation and the apoptosis of Schwann cells (SCs) in vitro. The cells were divided into different groups, and were treated for 48 h. Cell viability and apoptosis were evaluated using Cell Counting kit‑8 and annexin V/propidium iodide assays, respectively. The concentrations of 8‑hydroxy‑2‑deoxyguanosine (8‑OHdG) and peroxynitrite (ONOO‑) were detected using an enzyme‑linked immunosorbent assay. The presence of intracellular oxygen free radicals was confirmed using flow cytometric analysis. Colorimetric assays were performed to determine the activity of caspase‑3, and western blotting was performed to detect the protein expression levels of PARP‑1, cleaved PARP‑1, PAR, apoptosis‑inducing factor (AIF), B‑cell lymphoma 2 (Bcl‑2) and Bcl‑2‑associated X protein. HG was found to induce severe oxidative stress and promote the caspase‑dependent and caspase‑independent apoptosis of SCs. Treatment with HM inhibited HG‑induced oxidative stress by suppressing hydroxyl and ONOO‑ production, levels of 8‑OHdG, caspase‑3 activity and apoptosis in the SCs. Furthermore, treatment with HM downregulated the HG‑induced release of PAR, the activation of PARP‑1 and nuclear translocation of AIF, and upregulated the expression of Bcl‑2 in the SCs. These results indicated that HM inhibited the HG‑induced‑oxidative stress‑associated caspase

  5. Glucose-induced Ca2 + signals in rat pancreatic β cells

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using microfluorometry to assay intracellular Ca2+ , the influences of varied factors on glucose induced Ca22+ signals, such as glucose-induced initial decline phase (GIDP), Ca2+ oscillation, and Ca2+ release from internal stores, were investigated in single rat pancreatic β cells. Glucose was able to evoke GIDP even at non-stimulus concentration (5 mol/L), which is insufficient to induce Ca2+ spikes. GIDP was dependent on neither membrane depo larization nor extraeellular Ca2+ . However, GIDP was inhibited by thapsigargin, indicating a dependence on Ca2+ up take by Ca22+ stores. The glucose-induced calcium oscillation was inhibited when external Ca2+ was removed. However, thapsigargin could not block the Ca2+ oscillation. These results suggest that maintenance of Ca22+ oscillation requires ex tracellular Ca2+ but not Ca2+ stores. Glucose was able to evoke Ca2+ signals even in the absence of external Ca2+ . The glucose-induced Ca2+ release from intracellular Ca2+ stores was blocked by TTX. However, TTX had no effect on high K--induced Ca2+ store release, suggesting that membrane depolarization can directly release Ca2+ from some internal Ca2+ stores in β cells.

  6. High glucose induces the expression of osteopontin in blood vessels in vitro and in vivo.

    Science.gov (United States)

    Li, Tianjia; Ni, Leng; Liu, Xinnong; Wang, Zhanqi; Liu, Changwei

    2016-11-11

    Osteopontin (OPN) is involved in mineral metabolism and the inflammatory response while diabetes mellitus is associated with severe and extensive vascular calcification. Therefore, we speculated that OPN could be a key factor in the calcification and dysfunction of blood vessels exposed to high glucose. To identify the relationship between high glucose and OPN, we used high glucose medium to stimulate smooth muscle cells (SMCs) and vascular endothelial cells (VECs) in vitro and diabetic rats for in vivo analyses. As assessed by flow cytometry and western blots, SMC and VEC apoptosis levels increased with high glucose. Potassium and calcium uptake by cells were also increased with high glucose. These findings demonstrated the relationship between mineral metabolism and high glucose. Western blot and quantitative real time polymerase chain reaction analyses demonstrated that OPN increased in vitro with high glucose stimulation. The inflammatory factor ICAM1 and the inhibitory phosphorylation of endothelial nitric-oxide synthase (eNOS) (Thr495) were also upregulated by high glucose. In contrast, the anti-inflammatory factor Nrf2 and the activating phosphorylation of eNOS (Ser1177) were downregulated. Similar to the change of OPN, phosphorylated P38 was increased with high glucose. SB203580, an inhibitor of P38 phosphorylation, downregulated the expression of OPN and related inflammatory factors. Additionally, OPN was increased in the aortas and plasma of diabetic rats. In conclusion, our findings demonstrate that high glucose can induce the expression of OPN, which may be a key factor in the calcification and dysfunction of the vascular wall in diabetes.

  7. High glucose-induced oxidative stress represses sirtuin deacetylase expression and increases histone acetylation leading to neural tube defects.

    Science.gov (United States)

    Yu, Jingwen; Wu, Yanqing; Yang, Peixin

    2016-05-01

    Aberrant epigenetic modifications are implicated in maternal diabetes-induced neural tube defects (NTDs). Because cellular stress plays a causal role in diabetic embryopathy, we investigated the possible role of the stress-resistant sirtuin (SIRT) family histone deacetylases. Among the seven sirtuins (SIRT1-7), pre-gestational maternal diabetes in vivo or high glucose in vitro significantly reduced the expression of SIRT 2 and SIRT6 in the embryo or neural stem cells, respectively. The down-regulation of SIRT2 and SIRT6 was reversed by superoxide dismutase 1 (SOD1) over-expression in the in vivo mouse model of diabetic embryopathy and the SOD mimetic, tempol and cell permeable SOD, PEGSOD in neural stem cell cultures. 2,3-dimethoxy-1,4-naphthoquinone (DMNQ), a superoxide generating agent, mimicked high glucose-suppressed SIRT2 and SIRT6 expression. The acetylation of histone 3 at lysine residues 56 (H3K56), H3K14, H3K9, and H3K27, putative substrates of SIRT2 and SIRT6, was increased by maternal diabetes in vivo or high glucose in vitro, and these increases were blocked by SOD1 over-expression or tempol treatment. SIRT2 or SIRT6 over-expression abrogated high glucose-suppressed SIRT2 or SIRT6 expression, and prevented the increase in acetylation of their histone substrates. The potent sirtuin activator (SRT1720) blocked high glucose-increased histone acetylation and NTD formation, whereas the combination of a pharmacological SIRT2 inhibitor and a pan SIRT inhibitor mimicked the effect of high glucose on increased histone acetylation and NTD induction. Thus, diabetes in vivo or high glucose in vitro suppresses SIRT2 and SIRT6 expression through oxidative stress, and sirtuin down-regulation-induced histone acetylation may be involved in diabetes-induced NTDs. The mechanism underlying pre-gestational diabetes-induced neural tube defects (NTDs) is still elusive. Our study unravels a new epigenetic mechanism in which maternal diabetes-induced oxidative stress represses

  8. AMP-activated protein kinase acts as a negative regulator of high glucose-induced RANKL expression in human periodontal ligament cells

    Institute of Scientific and Technical Information of China (English)

    FENG Yuan; LIU Jia-qiang; LIU Hong-chen

    2012-01-01

    Background It is well known that the function of periodontal ligament cells may be affected by high glucose levels.This study investigated the direct effect of high glucose on the expression of receptor activator of nuclear factor-kappa B ligand (RANKL) in human PDL (hPDL) cells.In addition,we examined whether this effect was mediated via AMPK activation.Methods We examined the expression of osteoprotegerin in hPDL cells cultured at different concentrations of glucose using real-time polymerase chain reaction (PCR),and Western blotting analysis.AMPK phosphorylation in hPDL cells was studied using immunoprecipitate kinase assay and Western blotting.The effect of AMPK activation on RANKL expression in hPDL cells was investigated by real-time PCR and Western blotting.Results High glucose levels caused an increase in RANKL mRNA and protein expression in hPDL cells.Moreover,the amount of p-AMPK and AMPK activity was lower in hPDL cells exposed to high glucose levels than in cells exposed to normal glucose levels.Suppression of AMPK by Compound C augmented RANKL expression,and AMPK activation by metformin significantly decreased RANKL expression in hPDL cells.Additionally,metformin down-regulated RANKL expression in hPDL cells exposed to high glucose via AMPK activation.Conclusion High glucose-induced up-regulation of RANKL could be due to decreased AMPK activity,and AMPK activation may be involved in regulating of RANKL expression in hPDL cells.

  9. Quercetin and sesamin protect neuronal PC12 cells from high-glucose-induced oxidation, nitrosative stress, and apoptosis.

    Science.gov (United States)

    Bournival, Julie; Francoeur, Marc-André; Renaud, Justine; Martinoli, Maria-Grazia

    2012-06-01

    Complications of diabetes are now well-known to affect sensory, motor, and autonomic nerves. Diabetes is also thought to be involved in neurodegenerative processes characteristic of several neurodegenerative diseases. Indeed, it has been acknowledged recently that hyperglycemia-induced oxidative stress contributes to numerous cellular reactions typical of central nervous system deterioration. The goal of the present study was to evaluate the effects of the polyphenol quercetin and the lignan sesamin on high-glucose (HG)-induced oxidative damage in an in vitro model of dopaminergic neurons, neuronal PC12 cells. When incubated with HG (13.5 mg/mL), neuronal PC12 cells showed a significant increase of cellular death. Our results revealed that quercetin and sesamin defend neuronal PC12 cells from HG-induced cellular demise. An elevated level of reactive oxygen and nitrogen species is a consequence of improved oxidative stress after HG administration, and we demonstrated that this production diminishes with quercetin and sesamin treatment. We also found that quercetin and sesamin elicited an increment of superoxide dismutase activity. DNA fragmentation, Bax/Bcl-2 ratio, nuclear translocation of apoptosis-inducing factor, as well as poly(adenosine diphosphate [ADP]-ribose) polymerase cleavage were significantly reduced by quercetin and sesamin administration, affirming their antiapoptotic features. Also, HG treatment impacted caspase-3 cleavage, supporting caspase-3-dependent pathways as mechanisms of apoptotic death. Our results indicate a powerful role for these natural dietary compounds and emphasize preventive or complementary nutritional strategies for diabetes control.

  10. High Glucose-Induced PC12 Cell Death by Increasing Glutamate Production and Decreasing Methyl Group Metabolism

    Directory of Open Access Journals (Sweden)

    Minjiang Chen

    2016-01-01

    Full Text Available Objective. High glucose- (HG- induced neuronal cell death is responsible for the development of diabetic neuropathy. However, the effect of HG on metabolism in neuronal cells is still unclear. Materials and Methods. The neural-crest derived PC12 cells were cultured for 72 h in the HG (75 mM or control (25 mM groups. We used NMR-based metabolomics to examine both intracellular and extracellular metabolic changes in HG-treated PC12 cells. Results. We found that the reduction in intracellular lactate may be due to excreting more lactate into the extracellular medium under HG condition. HG also induced the changes of other energy-related metabolites, such as an increased succinate and creatine phosphate. Our results also reveal that the synthesis of glutamate from the branched-chain amino acids (isoleucine and valine may be enhanced under HG. Increased levels of intracellular alanine, phenylalanine, myoinositol, and choline were observed in HG-treated PC12 cells. In addition, HG-induced decreases in intracellular dimethylamine, dimethylglycine, and 3-methylhistidine may indicate a downregulation of methyl group metabolism. Conclusions. Our metabolomic results suggest that HG-induced neuronal cell death may be attributed to a series of metabolic changes, involving energy metabolism, amino acids metabolism, osmoregulation and membrane metabolism, and methyl group metabolism.

  11. Salidroside Reduces High-Glucose-Induced Podocyte Apoptosis and Oxidative Stress via Upregulating Heme Oxygenase-1 (HO-1) Expression.

    Science.gov (United States)

    Lu, Hua; Li, Ying; Zhang, Tao; Liu, Maodong; Chi, Yanqing; Liu, Shuxia; Shi, Yonghong

    2017-08-23

    BACKGROUND Hyperglycemia is one of the most dangerous factors causing diabetic nephropathy. Salidroside is considered to have the effects of reducing oxidative stress damage and improving cell viability. This study was performed to investigate whether and how salidroside reduces high-glucose (HG)-induced apoptosis in mouse podocytes. MATERIAL AND METHODS We examined whether salidroside could decrease HG-induced podocyte oxidative stress and podocyte apoptosis in vitro. The potential signaling pathways were also investigated. Podocytes (immortalized mouse epithelial cells) were treated with normal glucose (5.5 mM) as control or HG (30 mM), and then exposed to salidroside treatment. RESULTS HG enhanced the generation of intracellular reactive oxygen species (ROS) and apoptosis in podocytes. Salidroside reduced HG-induced apoptosis-related consequences via promoting HO-1 expression. Salidroside increased the expression level of phosphorylated Akt (p-Akt) and phosphorylated ILK (p-ILK), p-JNK, and p-ERK and localization of Nrf-2. JNK inhibitor and ILK inhibitor decreased HO-1 expression to different degrees. Moreover, specific siRNAs of ILK, Nrf-2, and HO-1, and inhibitors of HO-1 and ILK significantly increased ROS generation and Caspase9/3 expression in the presence of salidroside and HG. CONCLUSIONS The results suggest that salidroside reduces HG-induced ROS generation and apoptosis and improves podocytes viability by upregulating HO-1 expression. ILK/Akt, JNK, ERK1/2, p38 MAPK, and Nrf-2 are involved in salidroside-decreased podocyte apoptosis in HG condition.

  12. Effects of the New Aldose Reductase Inhibitor Benzofuroxane Derivative BF-5m on High Glucose Induced Prolongation of Cardiac QT Interval and Increase of Coronary Perfusion Pressure

    Directory of Open Access Journals (Sweden)

    C. Di Filippo

    2016-01-01

    Full Text Available This study investigated the effects of the new aldose reductase inhibitor benzofuroxane derivative 5(6-(benzo[d]thiazol-2-ylmethoxybenzofuroxane (BF-5m on the prolongation of cardiac QT interval and increase of coronary perfusion pressure (CPP in isolated, high glucose (33.3 mM D-glucose perfused rat hearts. BF-5m was dissolved in the Krebs solution at a final concentration of 0.01 μM, 0.05 μM, and 0.1 μM. 33.3 mM D-glucose caused a prolongation of the QT interval and increase of CPP up to values of 190 ± 12 ms and 110 ± 8 mmHg with respect to the values of hearts perfused with standard Krebs solution (11.1 mM D-glucose. The QT prolongation was reduced by 10%, 32%, and 41%, respectively, for the concentration of BF-5m 0.01 μM, 0.05 μM, and 0.1 μM. Similarly, the CPP was reduced by 20% for BF-5m 0.05 μM and by 32% for BF-5m 0.1 μM. BF-5m also increased the expression levels of sirtuin 1, MnSOD, eNOS, and FOXO-1, into the heart. The beneficial actions of BF-5m were partly abolished by the pretreatment of the rats with the inhibitor of the sirtuin 1 activity EX527 (10 mg/kg/day/7 days i.p. prior to perfusion of the hearts with high glucose + BF-5m (0.1 μM. Therefore, BF-5m supplies cardioprotection from the high glucose induced QT prolongation and increase of CPP.

  13. 葛根素对抗高糖诱导的血管低反应性的作用及其机制%Effect and mechanism of puerarin on high glucose-induced hypo-responses in vascular contraction

    Institute of Scientific and Technical Information of China (English)

    朱一苗; 倪超; 朱立; 沈岳良; 陈莹莹

    2011-01-01

    Objective: To examine the effect of puerarin on high glucose-induced decrease in contraction of isolated rat aortic rings, and to elucidate its underlying mechanism. Methods: The thoracic aortic tings with or without endothelium of male Sprague-Dawley rats were mounted on a bath system. Isometric contractions of aortic rings were measured. The activity of heme oxygenase-1 ( HO- 1 ) was also measured. Results: ①After incubation with 44 mmol/L of glucose (high glucose) for 4 h, the vascular contraction responses to phenylephrine(PE) decreased in an endothelium-dependent manner, when compared with the control group (containing 11 mmol/L of glucose). ②After coincubation with puerarin ( 10-10 ~ 10-8 mol/L) and high glucose, the decrease in contraction responses to PE of arteries was partly inhibited in a dose-dependent manner. ③After incubation with puerarin for 4 h, the HO- 1 activity of thoracic aorta increased; ZnPP, an inhibitor of HO- 1, abrogated the protection effect of puerarin. Conclusion: Puerarin could prevent the high glucose-induced decrease in contraction responses to PE in intact aortic rings. The mechanism might be involved in the activation of HO-1.%目的:研究葛根素是否可对抗高糖引起的血管低反应性,并探讨其作用机制.方法:采用血管环离体灌流装置,观察SD大鼠胸主动脉环的收缩反应;测定主动脉胆红素生成量反映血红素加氧酶-1(heme oxygenase-1,HO1)的活性.结果:①与空白对照组(含11mmol/L葡萄糖)相比,经44mmol/L葡萄糖(高糖)孵育血管4 h后,主动脉环对苯肾上腺素(PE)引起的血管收缩反应下降;且该作用通过内皮依赖性途径实现.②葛根素(10-10~10-8 mol/L)与高糖联合孵育,可剂量依赖性地改善高糖诱导的血管PE收缩反应的下降.③葛根素孵育血管后可引起血管HO-1活性增高;用ZnPP抑制HO-1的活性后,葛根素抗高糖损伤的作用被取消.结论:葛根素具有对抗高糖引起的血管收缩功能

  14. Glucose induces apoptosis of cardiomyocytes via microRNA-1 and IGF-1.

    Science.gov (United States)

    Yu, Xi-Yong; Song, Yao-Hua; Geng, Yong-Jian; Lin, Qiu-Xiong; Shan, Zhi-Xin; Lin, Shu-Guang; Li, Yangxin

    2008-11-21

    Glucose toxicity is an important initiator of cardiovascular disease, contributing to the development of cardiomyocyte death and diabetic complications. The present study investigated whether high glucose state could induce apoptosis of rat cardiomyocyte cell line H9C2 through microRNA regulated insulin-like growth factor (IGF-1) signaling pathway. Our data showed that H9C2 cells exposed to high glucose have increased miR-1 expression level, decreased mitochondrial membrane potential, increased cytochrome-c release, and increased apoptosis. Glucose induced mitochondrial dysfunction, cytochrome-c release and apoptosis was blocked by IGF-1. Using prediction algorithms, we identified 3'-untranslated regions of IGF-1 gene are the target of miR-1. miR-1 mimics, but not mutant miR-1, blocked the capacity of IGF-1 to prevent glucose-induced mitochondrial dysfunction, cytochrome-c release and apoptosis. In conclusion, our data demonstrate that IGF-1 inhibits glucose-induced mitochondrial dysfunction, cytochrome-c release and apoptosis and IGF-1's effect is regulated by miR-1.

  15. Fenofibrate attenuated glucose-induced mesangial cells proliferation and extracellular matrix synthesis via PI3K/AKT and ERK1/2.

    Directory of Open Access Journals (Sweden)

    Rui Zeng

    Full Text Available Excess mesangial extracellular matrix (ECM and mesangial cell proliferation is the major pathologic feature of diabetic nephropathy (DN. Fenofibrate, a PPARα agonist, has been shown to attenuate extracellular matrix formation in diabetic nephropathy. However, the mechanisms underlying this effect remain to be elucidated. In this study, the effect of fenofibrate on high-glucose induced cell proliferation and extracellular matrix exertion and its mechanisms were investigated in cultured rat mesangial cells by the methylthiazoletetrazolium (MTT assay, flow cytometry and western blot. The results showed that treatment of mesangial cells (MCs with fenofibrate repressed high-glucose induced up-regulation of extracellular matrix Collagen-IV, and inhibited entry of cell cycle into the S phase. This G1 arrest and ECM inhibition was caused by the reduction of phosphorylation and activation of extracellular signal-regulated kinase 1/2 (ERK1/2 and AKT. On the contrary, PPARα siRNA accelerated high glucose-induced cell cycle progression by ERK1/2 and AKT activation. Taken together, fenofibrate ameliorated glucose-induced mesangial cell proliferation and matrix production via its inhibition of PI3K/AKT and ERK1/2 signaling pathways. Such mechanisms may contribute to the favorable effects of treatment using fenofibrate in diabetic nephropathy.

  16. 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.

  17. Regulation of high glucose-induced apoptosis of brain pericytes by mitochondrial CA VA: A specific target for prevention of diabetic cerebrovascular pathology.

    Science.gov (United States)

    Price, Tulin O; Sheibani, Nader; Shah, Gul N

    2017-04-01

    Events responsible for cerebrovascular disease in diabetes are not fully understood. Pericyte loss is an early event that leads to endothelial cell death, microaneurysms, and cognitive impairment. A biochemical mechanism underlying pericyte loss is rapid respiration (oxidative metabolism of glucose). This escalation in respiration results from free influx of glucose into insulin-insensitive tissues in the face of high glucose levels in the blood. Rapid respiration generates superoxide, the precursor to all reactive oxygen species (ROS), and results in pericyte death. Respiration is regulated by carbonic anhydrases (CAs) VA and VB, the two isozymes expressed in mitochondria, and their pharmacologic inhibition with topiramate reduces respiration, ROS, and pericyte death. Topiramate inhibits both isozymes; therefore, in the earlier studies, their individual roles were not discerned. In a recent genetic study, we showed that mitochondrial CA VA plays a significant role in regulation of reactive oxygen species and pericyte death. The role of CA VB was not addressed. In this report, genetic knockdown and overexpression studies confirm that mitochondrial CA VA regulates respiration in pericytes, whereas mitochondrial CA VB does not contribute significantly. Identification of mitochondrial CA VA as a sole regulator of respiration provides a specific target to develop new drugs with fewer side effects that may be better tolerated and can protect the brain from diabetic injury. Since similar events occur in the capillary beds of other insulin-insensitive tissues such as the eye and kidney, these drugs may also slow the onset and progression of diabetic disease in these tissues.

  18. Regulation of Na(+)-K(+)-ATPase effected high glucose-induced myocardial cell injury through c-Src dependent NADPH oxidase/ROS pathway.

    Science.gov (United States)

    Yan, Xiaofei; Xun, Meng; Dou, Xiaojuan; Wu, Litao; Han, Yan; Zheng, Jin

    2017-08-15

    Depressed Na(+)/K(+)-ATPase activity has long been reported to be involved in diabetic-related cardiomyocyte death and cardiac dysfunction. However, the nature of directly regulating Na(+)-K(+)-ATPase in diabetic-related myocardial diseases remains unknown. Hyperglycemia is believed as one of major factors responsible for diabetic-related myocardial apoptosis and dysfunction. In this study, whether inhibiting Na(+)-K(+)-ATPase by ouabain or activating Na(+)-K(+)-ATPase by DRm217 has functions on high glucose (HG) -induced myocardial injury was investigated. Here we found that addition of DRm217 or ouabain to HG-treated cells had opposite effects. DRm217 decreased but ouabain increased HG-induced cell injury and apoptosis. This was mediated by changing Na(+)-K(+)-ATPase activity and Na(+)-K(+)-ATPase cell surface expression. The inhibition of Na(+)-K(+)-ATPase endocytosis alleviated HG-induced ROS accumulation. Na(+)-K(+)-ATPase·c-Src dependent NADPH oxidase/ROS pathway was also involved in the effects of ouabain and DRm217 on HG-induced cell injury. These novel results may help us to understand the important role of the Na(+)-K(+)-ATPase in diabetic cardiovascular diseases. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Fagopyrum tataricum (Buckwheat Improved High-Glucose-Induced Insulin Resistance in Mouse Hepatocytes and Diabetes in Fructose-Rich Diet-Induced Mice

    Directory of Open Access Journals (Sweden)

    Chia-Chen Lee

    2012-01-01

    Full Text Available Fagopyrum tataricum (buckwheat is used for the treatment of type 2 diabetes mellitus in Taiwan. This study was to evaluate the antihyperglycemic and anti-insulin resistance effects of 75% ethanol extracts of buckwheat (EEB in FL83B hepatocytes by high-glucose (33 mM induction and in C57BL/6 mice by fructose-rich diet (FRD; 60% induction. The active compounds of EEB (100 μg/mL; 50 mg/kg bw, quercetin (6 μg/mL; 3 mg/kg bw, and rutin (23 μg/mL; 11.5 mg/kg bw were also employed to treat FL83B hepatocytes and animal. Results indicated that EEB, rutin, and quercetin + rutin significantly improved 2-NBDG uptake via promoting Akt phosphorylation and preventing PPARγ degradation caused by high-glucose induction for 48 h in FL83B hepatocytes. We also found that EEB could elevate hepatic antioxidant enzymes activities to attenuate insulin resistance as well as its antioxidation caused by rutin and quercetin. Finally, EEB also inhibited increases in blood glucose and insulin levels of C57BL/6 mice induced by FRD.

  20. Fagopyrum tataricum (buckwheat) improved high-glucose-induced insulin resistance in mouse hepatocytes and diabetes in fructose-rich diet-induced mice.

    Science.gov (United States)

    Lee, Chia-Chen; Hsu, Wei-Hsuan; Shen, Siou-Ru; Cheng, Yu-Hsiang; Wu, She-Ching

    2012-01-01

    Fagopyrum tataricum (buckwheat) is used for the treatment of type 2 diabetes mellitus in Taiwan. This study was to evaluate the antihyperglycemic and anti-insulin resistance effects of 75% ethanol extracts of buckwheat (EEB) in FL83B hepatocytes by high-glucose (33 mM) induction and in C57BL/6 mice by fructose-rich diet (FRD; 60%) induction. The active compounds of EEB (100 μg/mL; 50 mg/kg bw), quercetin (6 μg/mL; 3 mg/kg bw), and rutin (23 μg/mL; 11.5 mg/kg bw) were also employed to treat FL83B hepatocytes and animal. Results indicated that EEB, rutin, and quercetin + rutin significantly improved 2-NBDG uptake via promoting Akt phosphorylation and preventing PPARγ degradation caused by high-glucose induction for 48 h in FL83B hepatocytes. We also found that EEB could elevate hepatic antioxidant enzymes activities to attenuate insulin resistance as well as its antioxidation caused by rutin and quercetin. Finally, EEB also inhibited increases in blood glucose and insulin levels of C57BL/6 mice induced by FRD.

  1. Nrf2 and NF-κB modulation by sulforaphane counteracts multiple manifestations of diabetic neuropathy in rats and high glucose-induced changes.

    Science.gov (United States)

    Negi, Geeta; Kumar, Ashutosh; Sharma, Shyam S

    2011-11-01

    High glucose driven reactive oxygen intermediates production and inflammatory damage are recognized contributors of nerve dysfunction and subsequent damage in diabetic neuropathy. Sulforaphane, a known chemotherapeutic agent holds a promise for diabetic neuropathy because of its dual antioxidant and anti-inflammatory activities. The present study investigated the effect of sulforaphane in streptozotocin (STZ) induced diabetic neuropathy in rats. For in vitro experiments neuro2a cells were incubated with sulforaphane in the presence of normal (5.5 mM) and high glucose (30 mM). For in vivo studies, sulforaphane (0.5 and 1 mg/kg) was administered six weeks post diabetes induction for two weeks. Motor nerve conduction velocity (MNCV), nerve blood flow (NBF) and pain behavior were improved and malondialdehyde (MDA) level was reduced by sulforaphane. Antioxidant effect of sulforaphane is derived from nuclear erythroid 2-related factor 2 (Nrf2) activation as demonstrated by increased expression of Nrf2 and downstream targets hemeoxygenase-1 (HO-1) and NAD(P)H:quinone oxidoreductase 1 (NQO-1) in neuro2a cells and sciatic nerve of diabetic animals. Nuclear factor-kappa B (NF-κB) inhibition seemed to be responsible for antiinflammatory activity of sulforaphane as there was reduction in NF-κB expression and IκB kinase (IKK) phosphorylation along with abrogation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression and tumor necrosis factor-α (TNF-α) and interleukine-6 (IL-6) levels. Here in this study we provide an evidence that sulforaphane is effective in reversing the various deficits in experimental diabetic neuropathy. This study supports the defensive role of Nrf2 in neurons under conditions of oxidative stress and also suggests that the NF-κB pathway is an important modulator of inflammatory damage in diabetic neuropathy.

  2. Hydrogen sulfide releasing aspirin, ACS14, attenuates high glucose-induced increased methylglyoxal and oxidative stress in cultured vascular smooth muscle cells.

    Science.gov (United States)

    Huang, Qian; Sparatore, Anna; Del Soldato, Piero; Wu, Lingyun; Desai, Kaushik

    2014-01-01

    Hydrogen sulfide is a gasotransmitter with vasodilatory and anti-inflammatory properties. Aspirin is an irreversible cyclooxygenase inhibitor anti-inflammatory drug. ACS14 is a novel synthetic hydrogen sulfide releasing aspirin which inhibits cyclooxygenase and has antioxidant effects. Methylglyoxal is a chemically active metabolite of glucose and fructose, and a major precursor of advanced glycation end products formation. Methylglyoxal is harmful when produced in excess. Plasma methylglyoxal levels are significantly elevated in diabetic patients. Our aim was to investigate the effects of ACS14 on methylglyoxal levels in cultured rat aortic vascular smooth muscle cells. We used cultured rat aortic vascular smooth muscle cells for the study. Methylglyoxal was measured by HPLC after derivatization, and nitrite+nitrate with an assay kit. Western blotting was used to determine NADPH oxidase 4 (NOX4) and inducible nitric oxide synthase (iNOS) protein expression. Dicholorofluorescein assay was used to measure oxidative stress. ACS14 significantly attenuated elevation of intracellular methylglyoxal levels caused by incubating cultured vascular smooth muscle cells with methylglyoxal (30 µM) and high glucose (25 mM). ACS14, but not aspirin, caused a significant attenuation of increase in nitrite+nitrate levels caused by methylglyoxal or high glucose. ACS14, aspirin, and sodium hydrogen sulfide (NaHS, a hydrogen sulfide donor), all attenuated the increase in oxidative stress caused by methylglyoxal and high glucose in cultured cells. ACS14 prevented the increase in NOX4 expression caused by incubating the cultured VSMCs with MG (30 µM). ACS14, aspirin and NaHS attenuated the increase in iNOS expression caused by high glucose (25 mM). In conclusion, ACS14 has the novel ability to attenuate an increase in methylglyoxal levels which in turn can reduce oxidative stress, decrease the formation of advanced glycation end products and prevent many of the known deleterious effects

  3. Hydrogen sulfide releasing aspirin, ACS14, attenuates high glucose-induced increased methylglyoxal and oxidative stress in cultured vascular smooth muscle cells.

    Directory of Open Access Journals (Sweden)

    Qian Huang

    Full Text Available Hydrogen sulfide is a gasotransmitter with vasodilatory and anti-inflammatory properties. Aspirin is an irreversible cyclooxygenase inhibitor anti-inflammatory drug. ACS14 is a novel synthetic hydrogen sulfide releasing aspirin which inhibits cyclooxygenase and has antioxidant effects. Methylglyoxal is a chemically active metabolite of glucose and fructose, and a major precursor of advanced glycation end products formation. Methylglyoxal is harmful when produced in excess. Plasma methylglyoxal levels are significantly elevated in diabetic patients. Our aim was to investigate the effects of ACS14 on methylglyoxal levels in cultured rat aortic vascular smooth muscle cells. We used cultured rat aortic vascular smooth muscle cells for the study. Methylglyoxal was measured by HPLC after derivatization, and nitrite+nitrate with an assay kit. Western blotting was used to determine NADPH oxidase 4 (NOX4 and inducible nitric oxide synthase (iNOS protein expression. Dicholorofluorescein assay was used to measure oxidative stress. ACS14 significantly attenuated elevation of intracellular methylglyoxal levels caused by incubating cultured vascular smooth muscle cells with methylglyoxal (30 µM and high glucose (25 mM. ACS14, but not aspirin, caused a significant attenuation of increase in nitrite+nitrate levels caused by methylglyoxal or high glucose. ACS14, aspirin, and sodium hydrogen sulfide (NaHS, a hydrogen sulfide donor, all attenuated the increase in oxidative stress caused by methylglyoxal and high glucose in cultured cells. ACS14 prevented the increase in NOX4 expression caused by incubating the cultured VSMCs with MG (30 µM. ACS14, aspirin and NaHS attenuated the increase in iNOS expression caused by high glucose (25 mM. In conclusion, ACS14 has the novel ability to attenuate an increase in methylglyoxal levels which in turn can reduce oxidative stress, decrease the formation of advanced glycation end products and prevent many of the known

  4. The protective effects of endogenous hydrogen sulfide modulator, S-propargyl-cysteine, on high glucose-induced apoptosis in cardiomyocytes: A novel mechanism mediated by the activation of Nrf2.

    Science.gov (United States)

    Yang, Hebei; Mao, Yicheng; Tan, Bo; Luo, Shanshan; Zhu, Yizhun

    2015-08-15

    S-propargyl-cysteine (SPRC) is a novel synthetic molecule exerting antioxidant effects via elevating generation of endogenous H2S. Our study aimed to elucidate possible antioxidant mechanisms of SPRC in hyperglycemia-induced oxidative stress. H9C2 cells were treated with SPRC or NaHS at the indicated concentration before being treated with high glucose for 48h. Follow-up experiments were based on detailed description given in Section 2. SD rats were injected with Streptozocin (STZ) to induce diabetes as previously reported. Diabetic rats were administrated with SPRC, NaHS or solution respectively for one week before the rats were killed for follow-up experiments. Our work found that SPRC remarkably attenuated high glucose induced generation of reactive oxygen species and apoptosis in H9C2 cells. SPRC increased stability and nuclear translocation of Nuclear factor erythroid 2-related factor 2 (Nrf2), up-regulated expression of antioxidant enzyme superoxide dismutase (SOD) and interfered with the interaction between Kelch-like ECH-associated protein 1 (KEAP1) and Nrf2. SPRC activated Nrf2 via Cystathionase-γ-lyase (CSE) and Akt pathway. CSE inhibitor PAG and Akt inhibitor LY294002 could reverse the protective effects of SPRC. Knockdown of Nrf2 by shRNA also blocked SPRC up-regulated expression of CSE. Similar results of protein expression and hypoglycemic activity of SPRC were observed in STZ induced diabetic rats.

  5. Changes of high-energy phosphorous compounds in skeletal muscle during glucose-induced thermogenesis in man. A 31P MR spectroscopy study

    DEFF Research Database (Denmark)

    Thomsen, C; Jensen, Karl Erik; Astrup, A

    1989-01-01

    By the use of invasive techniques, skeletal muscle has been shown to contribute to thermogenesis induced by glucose in humans. In an attempt to study this phenomenon by a non-invasive method, this study investigated intracellular high-energy phosphorous compounds in calf muscle by 31P MR spectros......By the use of invasive techniques, skeletal muscle has been shown to contribute to thermogenesis induced by glucose in humans. In an attempt to study this phenomenon by a non-invasive method, this study investigated intracellular high-energy phosphorous compounds in calf muscle by 31P MR...

  6. The mitochondrial Na+/Ca2+exchanger may reduce high glucose-induced oxidative stress and nucleotide-binding oligomerization domain receptor 3 inflammasome activation in endothelial cells

    Institute of Scientific and Technical Information of China (English)

    Yuan ZU; Li-Juan WAN; Shao-Yuan CUI; Yan-Ping GONG; Chun-Lin LI

    2015-01-01

    Background The mitochondrial Na+/Ca2+exchanger, NCLX, plays an important role in the balance between Ca2+influx and efflux across the mitochondrial inner membrane in endothelial cells. Mitochondrial metabolism is likely to be affected by the activity of NCLX because Ca2+activates several enzymes of the Krebs cycle. It is currently believed that mitochondria are not only centers of energy produc-tion but are also important sites of reactive oxygen species (ROS) generation and nucleotide-binding oligomerization domain receptor 3 (NLRP3) inflammasome activation. Methods&Results This study focused on NCLX function, in rat aortic endothelial cells (RAECs), induced by glucose. First, we detected an increase in NCLX expression in the endothelia of rats with diabetes mellitus, which was induced by an injection of streptozotocin. Next, colocalization of NCLX expression and mitochondria was detected using confocal analysis. Suppression of NCLX expression, using an siRNA construct (siNCLX), enhanced mitochondrial Ca2+influx and blocked efflux induced by glucose. Un-expectedly, silencing of NCLX expression induced increased ROS generation and NLRP3 inflammasome activation. Conclusions These findings suggest that NCLX affects glucose-dependent mitochondrial Ca2+signaling, thereby regulating ROS generation and NLRP3 in-flammasome activation in high glucose conditions. In the early stages of high glucose stimulation, NCLX expression increases to compensate in order to self-protect mitochondrial maintenance, stability, and function in endothelial cells.

  7. Serum response factor accelerates the high glucose-induced Epithelial-to-Mesenchymal Transition (EMT) via snail signaling in human peritoneal mesothelial cells.

    Science.gov (United States)

    He, Lijie; Lou, Weijuan; Ji, Lihua; Liang, Wei; Zhou, Meilan; Xu, Guoshang; Zhao, Lijuan; Huang, Chen; Li, Rong; Wang, Hanmin; Chen, Xiangmei; Sun, Shiren

    2014-01-01

    Epithelial-to-Mesenchymal Transition (EMT) induced by glucose in human peritoneal mesothelial cells (HPMCs) is a major cause of peritoneal membrane (PM) fibrosis and dysfunction. To investigate serum response factor (SRF) impacts on EMT-derived fibrosis in PM, we isolated HPMCs from the effluents of patients with end-stage renal disease (ESRD) to analyze alterations during peritoneal dialysis (PD) and observe the response of PM to SRF in a rat model. Our results demonstrated the activation and translocation of SRF into the nuclei of HPMCs under extensive periods of PD. Accordingly, HPMCs lost their epithelial morphology with a decrease in E-cadherin expression and an increase in α-smooth muscle actin (α-SMA) expression, implying a transition in phenotype. PD with 4.25% glucose solution significantly induced SRF up-regulation and increased peritoneal thickness. In immortal HPMCs, high glucose (HG, 60 mmol/L) stimulated SRF overexpression in transformed fibroblastic HPMCs. SRF-siRNA preserved HPMC morphology, while transfection of SRF plasmid into HPMCs caused the opposite effects. Evidence from electrophoretic mobility shift, chromatin immunoprecipitation and reporter assays further supported that SRF transcriptionally regulated Snail, a potent inducer of EMT, by directly binding to its promoter. Our data suggested that activation of SRF/Snail pathway might contribute to the progressive PM fibrosis during PD.

  8. Astragaloside IV, a novel antioxidant, prevents glucose-induced podocyte apoptosis in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Dingkun Gui

    Full Text Available Glucose-induced reactive oxygen species (ROS production initiates podocyte apoptosis, which represents a novel early mechanism leading to diabetic nephropathy (DN. Here, we tested the hypothesis that Astragaloside IV(AS-IV exerts antioxidant and antiapoptotic effects on podocytes under diabetic conditions. Apoptosis, albuminuria, ROS generation, caspase-3 activity and cleavage, as well as Bax and Bcl-2 mRNA and protein expression were measured in vitro and in vivo. Cultured podocytes were exposed to high glucose (HG with 50, 100 and 200 µg/ml of AS-IV for 24 h. AS-IV significantly attenuated HG-induced podocyte apoptosis and ROS production. This antiapoptotic effect was associated with restoration of Bax and Bcl-2 expression, as well as inhibition of caspase-3 activation and overexpression. In streptozotocin (STZ-induced diabetic rats, severe hyperglycemia and albuminuria were developed. Increased apoptosis, Bax expression, caspase-3 activity and cleavage while decreased Bcl-2 expression were detected in diabetic rats. However, pretreatment with AS-IV (2.5, 5, 10 mg·kg(-1·d(-1 for 14 weeks ameliorated podocyte apoptosis, caspase-3 activation, renal histopathology, podocyte foot process effacement, albuminuria and oxidative stress. Expression of Bax and Bcl-2 mRNA and protein in kidney cortex was partially restored by AS-IV pretreatment. These findings suggested AS-IV, a novel antioxidant, to prevent Glucose-Induced podocyte apoptosis partly through restoring the balance of Bax and Bcl-2 expression and inhibiting caspase-3 activation.

  9. 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

  10. 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.

  11. Pyruvate dehydrogenase activator corrects high glucose-induced dysfunctions in human umbilical vein endothelial cells%丙酮酸脱氢酶激动剂对糖诱导的内皮细胞功能紊乱的改善作用

    Institute of Scientific and Technical Information of China (English)

    万沁; 钟海花; 徐勇; 何建华; 童南伟

    2008-01-01

    [Objective] The aim of this study was to determine whether diisopropylamine dichloroacetate (DADA), a pyruvate dehydrogenase activator, has protective effects on functions of human umbilical vein endothelial cells (HUVECs) and the underlying mechanisms. [Methods] HUVECs were cultured in medium containing 5.5 mM or 30 mM glucose with or without various concentrations (1×10-5 M, 1×10-4 M or 1×10-3 M) of DADA. Expression of nitric oxide (NO) and soluble intercellular adhesion molecule-1 (sICAM-1) was determined by commercially available kits. Distribution and expression of PKCα and PKCδ were determined by laser-scanning confocal microscopy and by Western blot, respectively. [Results] Glucose at 30 mM decreased NO expression but increased sICAM-1 expression. However, these cellular dysfunctions were reversed to the normal levels by co-treatment with DADA.Moreover, DADA inhibited the translocation of PKCα from the plasma to the nucleus and the translocation of PKCδ from the plasma towards the membrane induced by high glucose in HUVECs, and inhibited the high glucose-induced overexpression of PKCδ. [Conclusions] Our findings indicate that DADA corrects high glucose-induced endothelial cell dysfunctions, probably by regulating the PKCα and PKCδ signaling pathways.%目的 研究丙酮酸脱氢酶激动剂二氯醋酸二异丙胺(DADA)对人脐静脉内皮细胞(HUVECs)的功能的影响及可能机制.方法 以体外培养的人脐静脉内皮细胞(HUVECs)作为靶细胞,进行了以下研究:1.DADA对高糖诱导的血管EC功能指标一氧化氮(NO)和可溶性细胞间黏附分子-1 (sICAM-1)的影响;2.用激光共聚焦显微镜及Western blotting杂交分别观察高糖诱导的PKCα、PKC δ的位置变化及蛋白表达量的影响;实验分组:对照组:浓度为5.5 mM;高糖组:浓度为30 mM;DADA(1×10-5 M,1×10-4 M or 1×10-3 M)+高糖组.结果 1.30 mM高糖可诱导EC功能紊乱:高糖可诱导EC功能紊乱:NO浓度降低,sICAM-1水平增

  12. Protective effect of serotonin derivatives on glucose-induced damage in PC12 rat pheochromocytoma cells.

    Science.gov (United States)

    Piga, Rosaria; Naito, Yuji; Kokura, Satoshi; Handa, Osamu; Yoshikawa, Toshikazu

    2010-01-01

    Oxidative damage is believed to be associated with ageing, cancer and several degenerative diseases. Previous reports have shown that safflower-seed extract and its major antioxidant constituents, serotonin hydroxycinnamic amides, possess a powerful free radical-scavenging and antioxidative activity, paying particular attention to atherosclerotic reactive oxygen species (ROS)-related dysfunctions. In the present report, we examined a still unknown cell-based mechanism of serotonin derivatives against ROS-related neuronal damage, phenomena that represent a crucial event in neurodegenerative diseases. Serotonin derivatives N-(p-coumaroyl)serotonin and N-feruloylserotonin exerted a protective effect on high glucose-induced cell death, inhibited the activation of caspase-3 which represents the last and crucial step within the cascade of events leading to apoptosis, and inhibited the overproduction of the mitochondrial superoxide, which represents the most dangerous radical produced by hyperglycaemia, by acting as scavengers of the superoxide radical. In addition, serotonin derivative concentration inside the cells and inside the mitochondria was increased in a time-dependent manner. Since recent studies support the assertion that mitochondrial dysfunctions related to oxidative damage are the major contributors to neurodegenerative diseases, these preliminary cell-based results identify a mitochondria-targeted antioxidant property of serotonin derivatives that could represent a novel therapeutic approach against the neuronal disorders and complications related to ROS.

  13. Postoperative myocardial performance during glucose-induced hypophosphatemia

    DEFF Research Database (Denmark)

    Rasmussen, A; Buus, S; Hessov, I

    1985-01-01

    Long-lasting hypophosphatemia was previously found to diminish myocardial performance. The present study aimed to elucidate if postoperative glucose-induced hypophosphatemia is of importance for myocardial performance. Sixteen patients undergoing elective colonic or rectal surgery were given 100 g....... As the preload (central venous pressure) and the afterload (arterial pressure) similarly were unchanged by the glucose infusion, glucose-induced hypophosphatemia following elective surgery was judged to lack importance for the myocardial performance....

  14. Adenylosuccinate Is an Insulin Secretagogue Derived from Glucose-Induced Purine Metabolism

    Directory of Open Access Journals (Sweden)

    Jessica R. Gooding

    2015-10-01

    Full Text Available Pancreatic islet failure, involving loss of glucose-stimulated insulin secretion (GSIS from islet β cells, heralds the onset of type 2 diabetes (T2D. To search for mediators of GSIS, we performed metabolomics profiling of the insulinoma cell line 832/13 and uncovered significant glucose-induced changes in purine pathway intermediates, including a decrease in inosine monophosphate (IMP and an increase in adenylosuccinate (S-AMP, suggesting a regulatory role for the enzyme that links the two metabolites, adenylosuccinate synthase (ADSS. Inhibition of ADSS or a more proximal enzyme in the S-AMP biosynthesis pathway, adenylosuccinate lyase, lowers S-AMP levels and impairs GSIS. Addition of S-AMP to the interior of patch-clamped human β cells amplifies exocytosis, an effect dependent upon expression of sentrin/SUMO-specific protease 1 (SENP1. S-AMP also overcomes the defect in glucose-induced exocytosis in β cells from a human donor with T2D. S-AMP is, thus, an insulin secretagogue capable of reversing β cell dysfunction in T2D.

  15. Investigation on the effect and mechanisms of hydrogen sulfide against high glucose-induced apoptosis in human umbilical vein endothelial cells%硫化氢对高糖诱导的人脐静脉内皮细胞凋亡的影响及其机制研究

    Institute of Scientific and Technical Information of China (English)

    宋成洁; 齐洪娜; 刘磊; 崔洁; 石玥; 闫长栋

    2011-01-01

    Objective To investigate the effects of hydrogen sulfide (H2S) against high glucose - induced apoptosis in human umbilical vein endothelial cells (HUVECs) and the mechanisms involved.Methods HUVECs were pre-treated with NaHS at the concentration of 10 μmol/L for 24 hours, followed by incubation with high glucose (33mmol/L) for 48 hours.The changes of nuclear morphology and the apoptosis of HUVECs were observed by DAPI fluorescence staining.Western blot was used to determine the expression of xanthine oxidase (XOD) and superoxide dismutase (SOD) in the HUVECs.Results DAPI staining assay revealed, compared with the normal control group, in high -glucose injury group, the number of apoptotic cells with dense stained nuclei and karyopyknosis or in the form of fluorescent granules significantly increased.Pre - treatment with NaHS ( 10 μmol/L) remarkably reduced the population of high glucose - induced apoptotic cells, with most cell chromatin appearing evenly diffusive low - intensity fluorescence.By Western blotting, at the end of 48 h of incubation of HUVECs in 33 mmoL/L glucose, SOD protein expression was decreased by 37.17%, whereas XOD protein expression increased by 47.06%, as compared with the control group; Compared with the high glucose group, SOD expression in 10μmol/L NaHS pretreated group increased by 27.52% and XOD protein expression decreased by 31.20%.Conclusion H2S can exert antagonist effect against high glucose - induced apoptosis in HUVECs, which was related to the inhibitory effect of H2S on the high glucose - induced downregulation of SOD and upregulation of XOD in HUVECs.%目的 观察硫化氢(hydrogen sulfide,H2S)对内皮细胞凋亡的影响,并从抗氧化的角度初步探讨其作用机制.方法 以硫氢化钠(sodium hydrosulfide,NaHS)作H2S的供体,人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVECs)经10 μmol/L NaHS预孵育24 h后加入33 mmol/L葡萄糖(高糖)作用48 h,以正常

  16. Palmitate potentiation of glucose-induced insulin release: a study using 2-bromopalmitate.

    Science.gov (United States)

    Parker, S M; Moore, P C; Johnson, L M; Poitout, V

    2003-10-01

    The mechanisms whereby fatty acids (FA) potentiate glucose-induced insulin secretion from the pancreatic beta cell are incompletely understood. In this study, the effects of palmitate on insulin secretion were investigated in isolated rat islets. Palmitate did not initiate insulin secretion at nonstimulatory glucose concentrations, but markedly stimulated insulin release at concentrations of glucose > or = 5.6 mmol/L. At concentrations of palmitate > or =0.5 mmol/L, the important determinant of the potency of the FA was its unbound concentration. At total concentrations bromopalmitate did not affect palmitate oxidation, but significantly diminished palmitate esterification into cellular lipids. Neither methyl palmitate, which is not activated into a long-chain acyl-CoA ester, nor 2-bromopalmitate affected glucose-stimulated insulin release. Further, 2-bromopalmitate partly inhibited the potentiating effect of palmitate. These results support the concept that FA potentiation of insulin release is mediated by FA-derived signals generated in the esterification pathway.

  17. Glycated albumin suppresses glucose-induced insulin secretion by impairing glucose metabolism in rat pancreatic β-cells

    Directory of Open Access Journals (Sweden)

    Muto Takashi

    2011-04-01

    Full Text Available Abstract Background Glycated albumin (GA is an Amadori product used as a marker of hyperglycemia. In this study, we investigated the effect of GA on insulin secretion from pancreatic β cells. Methods Islets were collected from male Wistar rats by collagenase digestion. Insulin secretion in the presence of non-glycated human albumin (HA and GA was measured under three different glucose concentrations, 3 mM (G3, 7 mM (G7, and 15 mM (G15, with various stimulators. Insulin secretion was measured with antagonists of inducible nitric oxide synthetase (iNOS, and the expression of iNOS-mRNA was investigated by real-time PCR. Results Insulin secretion in the presence of HA and GA was 20.9 ± 3.9 and 21.6 ± 5.5 μU/3 islets/h for G3 (P = 0.920, and 154 ± 9.3 and 126.1 ± 7.3 μU/3 islets/h (P = 0.046, for G15, respectively. High extracellular potassium and 10 mM tolbutamide abrogated the inhibition of insulin secretion by GA. Glyceraldehyde, dihydroxyacetone, methylpyruvate, GLP-1, and forskolin, an activator of adenylate cyclase, did not abrogate the inhibition. Real-time PCR showed that GA did not induce iNOS-mRNA expression. Furthermore, an inhibitor of nitric oxide synthetase, aminoguanidine, and NG-nitro-L-arginine methyl ester did not abrogate the inhibition of insulin secretion. Conclusion GA suppresses glucose-induced insulin secretion from rat pancreatic β-cells through impairment of intracellular glucose metabolism.

  18. 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...

  19. Effect of GLP-1 on high glucose-induced human umbilical vein endothelial cell apoptosis and mechanism%胰高血糖素样肽-1对高糖诱导人脐静脉内皮细胞凋亡的影响及相关机制

    Institute of Scientific and Technical Information of China (English)

    袁小燕; 陈科; 何红晖; 赵立玲; 莫朝晖

    2013-01-01

    Objective: To investigate the effects of glucagon-like peptide-1(GLP-1)on high glucose-induced apoptosis of human umbilical vein endothelial cells (HUVECs) and the mechanism involved. Methods: HUVECs were cultured under varying conditions for 48 h, and the cell viability was spectrophotometrically measured by MTT assay. Flow cytometry detected the ratio of cell apoptosis. Western blot detected the protein levels of p-Akt and p-eNOS, while NO assay kit detected the NO concentration. Results: Treatment of high glucose (33 mmol/L) for 48 h signiifcantly decreased the HUVECs viability and induced the apoptosis of HUVECs, concomitant with decreased Akt and eNOS phosphorylation leves and subsequent NO production. Treatment with GLP-1 (3 nmol/L) for 48 h in the high glucose group increased the HUVECs viability (P Conclusion: GLP-1 can ameliorate high glucose-induced HUVECs apoptosis, which is probably related to the up-regulation of PI3K/Akt/eNOS pathway.%目的:探讨胰高血糖素样肽-1(glucagon-like peptide-1,GLP-1)对高糖诱导人脐静脉内皮细胞(human umbilical vein endothelial cells,HUVECs)凋亡的影响及相关机制。方法:HUVECs加入不同处理因素后分组,分别培养48 h后, MTT检测细胞活力;流式细胞仪检测细胞早期凋亡率;Western印迹测定细胞p-Akt,p-eNOS水平;NO试剂盒检测NO浓度。结果:高糖(33 mmol/L)培养48 h后HUVECs细胞活力下降(P<0.05),细胞凋亡率增加(P<0.01),细胞p-Akt, p-eNOS,NO水平均下降(P<0.05);高糖条件下加入GLP-1(3 nmol/L)培养48 h,与高糖组相比较,HUVECs细胞活力增加(P<0.01),细胞凋亡率减少(P<0.05),细胞p-Akt,p-eNOS,NO水平均增加(P<0.05);PI3K抑制剂wortmannine(100 nmol/L)可以阻断GLP-1的抗凋亡作用及其对p-Akt蛋白、p-eNOS蛋白及NO水平的影响;eNOS抑制剂L-NAME(100μmol/L)仅能阻断GLP-1的抗凋亡作用及对NO水平的影响,不影响p-Akt蛋白的表达。结论:GLP-1

  20. 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.

  1. Effect of lipitor on high glucose-induced HUVEC apoptosis and PI3K/AKT/eNOS signal pathway%立普妥对高糖诱导的HUVEC凋亡及PI3 K/AKT/eNOS信号通路的影响

    Institute of Scientific and Technical Information of China (English)

    刘志辉

    2016-01-01

    目的 探讨立普妥对高糖诱导的人脐静脉内皮细胞(HUVEC)的凋亡及对磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(AKT)/内皮型一氧化氮(eNOS)信号通路的影响.方法 实验分为正常组,模型组(33.3 mol/L葡萄糖),立普妥组(33.3 mol/L葡萄糖+0.1,1,10μmol/L);MTT法检测各组HUVEC活力;倒置显微镜拍照检测各组HUVEC形态;Annexin V-FITC/PI流式双染法检测各组HUVEC凋亡;Gries法检测各组HUVEC上清NO含量;Western blot分析PI3K/AKT激活状况及eNOS的表达情况.结果 与正常组比较,高糖组中HUVEC皱缩,变圆变亮,细胞活力降低,细胞早期凋亡和晚期凋亡率显著提高,NO含量及eNOS、PI3K表达量及AKT磷酸化程度降低,差异均具有显著性(P<0.05);与模型组比较,1,10μmol/L立普妥组中HUVEC形态恢复,细胞活力上升,PI3K表达量提高,差异均具有显著性(P<0.05);0.1,1,10μmol/L立普妥组HUVEC凋亡程度下降,NO含量、eNOS表达量提高,AKT磷酸化水平上升,差异均具有显著性(P<0.05).结论 立普妥可抵抗高糖诱导的HUVEC凋亡,是通过激活PI3 K/AKT/eNOS信号通路实现的.%Objectives To explore effect of lipitor on apoptosis and phosphatidyl inositol-3-kinase ( PI3K)/protein kinase B ( AKT )/endothelial nitric oxide synthase ( eNOS ) signal pathway in high glucose-induced human umbilical vein endothelial cell ( HUVEC) .Methods The cases were randomly divided into normal control group, model control group (33.3 mol/L glucose), lipitor low, medium, high-dose group (0.1,1,10 μmol/L lipitor).The viability of HUVEC was detected by MTT assay.The morphology of HUVEC was photographed by inverted microscope.The apoptosis of HUVEC was examed by Annexin V-FITC/PI flow dual-staining method.The concertration of NO in HUVEC supernatant was exmaed by Gries method.The activation of PI3K/AKT and expression of eNOS was assayed by western blot.Results HUVEC was shrinkage, rounded and brighten, the viability of HUVEC decreased, early and late

  2. Effect of low temperatures on glucose-induced insulin secretion and ionic fluxes in rat pancreatic islets.

    Science.gov (United States)

    Escolar, J C; Hoo-Paris, R; Castex, C; Sutter, B C

    1987-11-01

    The direct effect of cold on the inhibition of B cell secretion is well known in hibernating and experimentally hypothermic mammals. This temperature dependency may result from the inhibition of ion transport across the membranes. In order to verify this hypothesis, ionic effluxes and insulin secretion from rat islets loaded with 86Rb+ and 45Ca+ were measured during perifusion. At 37 degrees C, the rise in glucose concentration from zero to 16.7 mmol/l provoked a rapid decrease in 86Rb+ efflux, an early fall and subsequent rise in 45Ca2+ efflux and a typical biphasic pattern of insulin secretion. At 27 degrees C, glucose induced only a very slight increase in insulin secretion, while the fluxes of radioactive ions were not significantly modified in amplitude but were clearly delayed. At 17 degrees C, no insulin response to glucose was observed and the decrease in K+ conductance indicated by 86Rb+ flux decrease was less temperature-dependent than the movement of Ca2+. After supplementary stimulation with a high extracellular concentration of Ca2+, insulin secretion was enhanced at 27 degrees C and reached levels induced by glucose alone at 37 degrees C. An increase in hormone secretion occurred even at 17 degrees C, but only during a first phase of secretion. Regular increases in temperature potentiated insulin secretion and provoked changes in ionic fluxes which suggest that B cell depolarization (86Rb+ flux decrease) induced by glucose can occur at 15 degrees C but cannot induce the opening of voltage-dependent Ca2+ channels (increase in 45Ca2+ efflux) until temperatures higher than 27 degrees C are reached.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. 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.

  4. Glutamine enhances glucose-induced mesangial cell proliferation.

    Science.gov (United States)

    Lagranha, Claudia J; Doi, Sonia Q; Pithon-Curi, Tania C; Curi, Rui; Sellitti, Donald F

    2008-05-01

    The proliferation of mesangial cells (MC) in the presence of glutamine (0-20 mM) was determined in both low (5 mM) and high (25 mM) glucose-containing medium. Glutamine in a high glucose (HG) environment increased cell proliferation in a dose-dependent manner. Inhibition of glutamine:fructose 6-phosphate amidotransferase (GFAT) and of phosphodiesterase significantly reduced glutamine-induced proliferation. Supraphysiologic levels of glutamine increase MC proliferation in a HG milieu via GFAT and cAMP-dependent pathways, suggesting that glutamine could pose a risk for diabetic nephropathy.

  5. 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.

  6. Glucose-induced β cell production of IL-1β contributes to glucotoxicity in human pancreatic islets

    Science.gov (United States)

    Maedler, Kathrin; Sergeev, Pavel; Ris, Frédéric; Oberholzer, José; Joller-Jemelka, Helen I.; Spinas, Giatgen A.; Kaiser, Nurit; Halban, Philippe A.; Donath, Marc Y.

    2002-01-01

    In type 2 diabetes, chronic hyperglycemia is suggested to be detrimental to pancreatic β cells, causing impaired insulin secretion. IL-1β is a proinflammatory cytokine acting during the autoimmune process of type 1 diabetes. IL-1β inhibits β cell function and promotes Fas-triggered apoptosis in part by activating the transcription factor NF-κB. Recently, we have shown that increased glucose concentrations also induce Fas expression and β cell apoptosis in human islets. The aim of the present study was to test the hypothesis that IL-1β may mediate the deleterious effects of high glucose on human β cells. In vitro exposure of islets from nondiabetic organ donors to high glucose levels resulted in increased production and release of IL-1β, followed by NF-κB activation, Fas upregulation, DNA fragmentation, and impaired β cell function. The IL-1 receptor antagonist protected cultured human islets from these deleterious effects. β cells themselves were identified as the islet cellular source of glucose-induced IL-1β. In vivo, IL-1β–producing β cells were observed in pancreatic sections of type 2 diabetic patients but not in nondiabetic control subjects. Similarly, IL-1β was induced in β cells of the gerbil Psammomys obesus during development of diabetes. Treatment of the animals with phlorizin normalized plasma glucose and prevented β cell expression of IL-1β. These findings implicate an inflammatory process in the pathogenesis of glucotoxicity in type 2 diabetes and identify the IL-1β/NF-κB pathway as a target to preserve β cell mass and function in this condition. PMID:12235117

  7. Cysteine analogues potentiate glucose-induced insulin release in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Ammon, H.P.; Hehl, K.H.; Enz, G.; Setiadi-Ranti, A.; Verspohl, E.J.

    1986-12-01

    In rat pancreatic islets, cysteine analogues, including glutathione, acetylcysteine, cysteamine, D-penicillamine, L-cysteine ethyl ester, and cysteine-potentiated glucose (11.1 mM) induced insulin secretion in a concentration-dependent manner. Their maximal effects were similar and occurred at approximately 0.05, 0.05, 0.1, 0.5, 1.0, 1.0 mM, respectively. At substimulatory glucose levels (2.8 mM), insulin release was not affected by these compounds. In contrast, thiol compounds, structurally different from cysteine and its analogues, such as mesna, tiopronin, meso-2,3-dimercaptosuccinic acid (DMSA), dimercaprol (BAL), beta-thio-D-glucose, as well as those cysteine analogues that lack a free-thiol group, including L-cystine, cystamine, D-penicillamine disulfide, S-carbocysteine, and S-carbamoyl-L-cysteine, did not enhance insulin release at stimulatory glucose levels (11.1 mM); cystine (5 mM) was inhibitory. These in vitro data indicate that among the thiols tested here, only cysteine and its analogues potentiate glucose-induced insulin secretion, whereas thiols that are structurally not related to cysteine do not. This suggests that a cysteine moiety in the molecule is necessary for the insulinotropic effect. For their synergistic action to glucose, the availability of a sulfhydryl group is also a prerequisite. The maximal synergistic action is similar for all cysteine analogues tested, whereas the potency of action is different, suggesting similarity in the mechanism of action but differences in the affinity to the secretory system.

  8. The protective effects of beta-casomorphin-7 against glucose -induced renal oxidative stress in vivo and vitro.

    Directory of Open Access Journals (Sweden)

    Wei Zhang

    Full Text Available Oxidative stress is implicated in the pathogenesis of diabetic nephropathy. The present study aimed to investigate the effect of β-casomorphin-7 (BCM7 on the oxidative stress occurring in kidney tissue in streptozotocin (STZ-induced diabetic rats and proximal tubular epithelial cells (NRK-52E exposure to high glucose (HG by using biochemical methods. There is a significant decrease in plasma insulin and a significant increase in plasma glucagon in the rats of diabetic group. Oral administration of BCM7 for 30 days to rats with STZ-induced diabetes resulted in a significant increase in serum level of insulin, and a decrease in the level of glucagon. Moreover, rats with STZ-induced diabetes had lower levels of superoxide dismutase (SOD, glutathione peroxidase (GPx and total antioxidative capacity (T-AOC, higher levels of malondialdehyde (MDA and hydrogen peroxide (H2O2 in the kidney than that in the control rats. The administration of BCM7 altered the changes of SOD, GPx, T-AOC, MDA and H2O2 in the kidney of diabetic rats. Furthermore, BCM7 alleviated high glucose-induced decreasement in SOD and GPx activity, increasement in MDA contents in the NRK-52E cells. BCM7 ameliorated the changes of angiotensin converting enzyme (ACE and ACE2 levels in the kidney of diabetic rats and BCM7 lowered the levels of angiotensin (AngII in the kidney of diabetic rats and culture medium for cells. Moreover losartan (antagonist of angiotensin II type I receptor lowered the high glucose-induced oxidative stress in the NRK-52E cells. Our results suggest that administration of BCM7 would alleviate high glucose-induced renal oxidative stress in vivo and in vitro, which may be associated with down regulation of the concentration of Ang II partly.

  9. The protective effect of magnesium lithospermate B against glucose-induced intracellular oxidative damage

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jian [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Xiangya School of Medicine, Changsha 410078 (China); Ren, Xian [Shanghai Green Valley Pharmaceutical Co., Ltd., Shanghai 201304 (China); Hou, Rui-ying; Dai, Xing-ping [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Xiangya School of Medicine, Changsha 410078 (China); Zhao, Ying-chun [Laboratories of Functional Genomics and Proteomics, Creighton University Medical Center, Omaha, NE 68131 (United States); Xu, Xiao-jing; Zhang, Wei; Zhou, Gan; Zhou, Hong-hao [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Xiangya School of Medicine, Changsha 410078 (China); Liu, Zhao-qian, E-mail: liuzhaoqian63@126.com [Institute of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics, Central South University, Xiangya School of Medicine, Changsha 410078 (China)

    2011-07-22

    Highlights: {yields} LAB reduced the ROS production in HEK293T cells cultured under oxidative stress. High dose of glucose enhanced the expression of HO-1 mRNA and HO-1 protein in a time-dependent manner. {yields} LAB enhanced the expression of HO-1 mRNA and HO-1 protein in a dose-dependent manner treated with high dose of glucose. {yields} LAB plays an important role against glucose-induced intracellular oxidative damage. {yields} The enhanced expression of HO-1 mRNA and HO-1 protein caused by LAB is regulated via Nrf2 signal pathway. -- Abstract: Objectives: To investigate the effects of magnesium lithospermate B (LAB) on intracellular reactive oxygen species (ROS) production induced by high dose of glucose or H{sub 2}O{sub 2}, we explored the influences of LAB on the expression of heme oxygenase-1 (HO-1) and nuclear factor E2-related factor-2 (Nrf2) in HEK293T cells after treatment with high dose of glucose. Materials and methods: The total nuclear proteins in HEK293T cells were extracted with Cytoplasmic Protein Extraction Kit. The ROS level was determined by flow cytometry. The mRNA and protein expression of HO-1 and Nrf2 were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot. Results: LAB reduced the ROS production in HEK293T cells cultured under oxidative stress. High dose of glucose enhanced the expression of HO-1 mRNA and HO-1 protein in a time-dependent manner. LAB enhanced the expression of HO-1 mRNA and HO-1 protein in a dose-dependent manner treated with high dose of glucose. The amount of Nrf2 translocation was enhanced after cells were pretreated with 50 {mu}mol/L or 100 {mu}mol/L LAB. Silencing of Nrf2 gene eliminated the enhanced expression of HO-1 protein induced by high dose of glucose plus LAB. Conclusions: LAB plays an important role against glucose-induced intracellular oxidative damage. The enhanced expression of HO-1 mRNA and HO-1 protein caused by LAB is regulated via Nrf2 signal pathway.

  10. Effect of essential fatty acids on glucose-induced cytotoxicity to retinal vascular endothelial cells

    Directory of Open Access Journals (Sweden)

    Shen Junhui

    2012-07-01

    high-glucose-induced VEGF secretion by RF/6A cells. Conclusions These results suggest that EFAs such as ALA and LA may have beneficial action in the prevention of high glucose-induced cellular damage.

  11. Statins suppress glucose-induced plasminogen activator inhibitor-1 expression by regulating RhoA and nuclear factor-κB activities in cardiac microvascular endothelial cells.

    Science.gov (United States)

    Ni, Xiao-Qing; Zhu, Jian-Hua; Yao, Ning-Hua; Qian, Juan; Yang, Xiang-Jun

    2013-01-01

    The aim of this study was to investigate the possible proinflammatory signaling pathways involved in statin inhibition of glucose-induced plasminogen activator inhibitor-1 (PAI-1) expression in cardiac microvascular endothelial cells (CMECs). Primary rat CMECs were grown in the presence of 5.7 or 23 mmol/L glucose. PAI-1 mRNA and protein expression levels were measured by realtime polymerase chain reaction, Western blotting and enzyme-linked immunosorbent assay, respectively. A pull-down assay was performed to determine RhoA activity. IκBα protein expression was measured by Western blotting, nuclear factor (NF)-κB activation was detected by electrophoretic mobility shift assay and its transcription activity was determined by a dual luciferase reporter gene assay. PAI-1 mRNA and protein expression levels were both increased with high glucose concentrations, but they were significantly suppressed by simvastatin and atorvastatin treatment (P statins (P statins may occur partly by regulating the RhoA/ROCK-NF-κB pathway. The multifunctional roles of statins may be particularly beneficial for patients with metabolic syndrome.

  12. Ethanol extract of Moringa oliefera prevents in vitro glucose induced cataract on isolated goat eye lens

    Directory of Open Access Journals (Sweden)

    Raghvendra Kurmi

    2014-01-01

    Full Text Available Aim of Study: The aim of current work was to evaluate in vitro anticataract potential of Moringa oliefera extract. Materials and Methods: Goat eye lenses were divided into 4 groups; Group served as control, Group II as toxic control, Group III and Group IV were incubated in extract (250 μg/ml and 500 μg/ml of extract of M. oliefera Group II, III and IV were incubated in 55 mM glucose in artificial aqueous humor to induce lens opacification. Estimation of total, water soluble protein, catalase, glutathione and malondialdehyde along with photographic evaluation of lens was done. Results: Group II (toxic control lenses showed high amount of MDA (Malondialdehyde, soluble, insoluble protein, decreased catalase and glutathione levels, while lenses treated with Moringa oliefera extract (Group III and Group IV showed significant (FNx01 P < 0.05 reduction in MDA and increased level of catalase, glutathione, total and soluble protein. Conclusion: Results of present findings suggest protective effect of Moringa oliefera in prevention of in vitro glucose induced cataract.

  13. Glucose-induced lipogenesis in pancreatic beta-cells is dependent on SREBP-1

    DEFF Research Database (Denmark)

    Sandberg, Maria B; Fridriksson, Jakob; Madsen, Lise

    2005-01-01

    binding proteins in glucose-induced lipogenesis in the pancreatic beta-cell line INS-1E. We show that glucose induces SREBP-1c expression and SREBP-1 activity independent of insulin secretion and signaling. Using adenoviral expression of SREBP-1c and a SREBP-mutant we show that lipogenic gene expression......, de novo fatty acid synthesis and lipid accumulation are induced primarily through sterol-regulatory elements (SREs) and not E-Boxes. Adenoviral expression of a dominant negative SREBP compromises glucose induction of some lipogenic genes and significantly reduces glucose-induction of de novo fatty...

  14. 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...

  15. Role of Peroxisome Proliferator-Activated Receptor Gamma in Glucose-induced Insulin Secretion

    Institute of Scientific and Technical Information of China (English)

    Ze-Kuan XU; Neng-Guin CHEN; Chang-Yan MA; Zhuo-Xian MENG; Yu-Jie SUN; Xiao HAN

    2006-01-01

    Peroxisome proliferator-activated receptor (PPAR) isoforms (α and γ) are known to be expressed in pancreatic islets as well as in insulin-producing cell lines. Ligands of PPAR have been shown to enhance glucose-induced insulin secretion in rat pancreatic islets. However, their effect on insulin secretion is still unclear. To understand the molecular mechanism by which PPARγ exerts its effect on glucoseinduced insulin secretion, we examined the endogenous activity of PPAR isoforms, and studied the PPARγfunction and its target gene expression in INS-1 cells. We found that: (1) endogenous PPARγ was activated in a ligand-dependent manner in INS-1 cells; (2) overexpression of PPARγ in the absence of PPARγ ligands enhanced glucose-induced insulin secretion, which indicates that the increased glucose-induced insulin secretion is a PPARγ-mediated event; (3) the addition of both PPARγ and retinoid X receptor (RXR) ligands showed a synergistic effect on the augmentation of reporter activity, suggesting that the hetero-dimerization of PPARγand RXR is required for the regulation of the target genes; (4) PPARs upregulated both the glucose transporter 2 (GLUT2) and Cbl-associated protein (CAP) genes in INS-1 cells. Our findings suggest an important mechanistic pathway in which PPARγ enhances glucose-induced insulin secretion by activating the expression of GLUT2 and CAP genes in a ligand-dependent manner.

  16. 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.

  17. 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.

  18. Nerve growth factor blocks the glucose-induced down-regulation of caveolin-1 expression in Schwann cells via p75 neurotrophin receptor signaling.

    Science.gov (United States)

    Tan, Wenbin; Rouen, Shefali; Barkus, Kristin M; Dremina, Yelena S; Hui, Dongwei; Christianson, Julie A; Wright, Douglas E; Yoon, Sung Ok; Dobrowsky, Rick T

    2003-06-20

    Altered neurotrophism in diabetic peripheral neuropathy (DPN) is associated in part with substantial degenerative changes in Schwann cells (SCs) and an increased expression of the p75 neurotrophin receptor (p75NTR). Caveolin-1 (Cav-1) is highly expressed in adult SCs, and changes in its expression can regulate signaling through Erb B2, a co-receptor that mediates the effects of neuregulins in promoting SC growth and differentiation. We examined the hypothesis that hyperglycemia-induced changes in Cav-1 expression and p75NTR signaling may contribute to altered neurotrophism in DPN by modulating SC responses to neuregulins. In an animal model of type 1 diabetes, hyperglycemia induced a progressive decrease of Cav-1 in SCs of sciatic nerve that was reversed by insulin therapy. Treatment of primary neonatal SCs with 20-30 mm d-glucose, but not l-glucose, was sufficient to inhibit transcription from the Cav-1 promoter and decrease Cav-1 mRNA and protein expression. Hyperglycemia prolonged the kinetics of Erb B2 phosphorylation and significantly enhanced the mitogenic response of SCs to neuregulin1-beta1, and this effect was mimicked by the forced down-regulation of Cav-1. Intriguingly, nerve growth factor antagonized the enhanced mitogenic response of SCs to neuregulin1-beta1 and inhibited the glucose-induced down-regulation of Cav-1 transcription, mRNA, and protein expression through p75NTR-dependent activation of JNK. Our data suggest that Cav-1 down-regulation may contribute to altered neurotrophism in DPN by enhancing the response of SCs to neuregulins and that p75NTR-mediated JNK activation may provide a mechanism for the neurotrophic modulation of hyperglycemic stress.

  19. Fructose impairs glucose-induced hepatic triglyceride synthesis

    OpenAIRE

    Boros Laszlo G; Yong William H; Young Stephen; Dhawan Tania; Huang Danshan; Heaney Anthony P

    2011-01-01

    Abstract Obesity, type 2 diabetes and hyperlipidemia frequently coexist and are associated with significantly increased morbidity and mortality. Consumption of refined carbohydrate and particularly fructose has increased significantly in recent years and has paralled the increased incidence of obesity and diabetes. Human and animal studies have demonstrated that high dietary fructose intake positively correlates with increased dyslipidemia, insulin resistance, and hypertension. Metabolism of ...

  20. 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

  1. Carnitine protects the nematode Caenorhabditis elegans from glucose-induced reduction of survival depending on the nuclear hormone receptor DAF-12

    Energy Technology Data Exchange (ETDEWEB)

    Deusing, Dorothé Jenni, E-mail: Dorothe.J.Deusing@ernaehrung.uni-giessen.de; Beyrer, Melanie, E-mail: m.beyrer@web.de; Fitzenberger, Elena, E-mail: Elena.Fitzenberger@ernaehrung.uni-giessen.de; Wenzel, Uwe, E-mail: uwe.wenzel@ernaehrung.uni-giessen.de

    2015-05-08

    Besides its function in transport of fatty acids into mitochondria in order to provide substrates for β-oxidation, carnitine has been shown to affect also glucose metabolism and to inhibit several mechanisms associated with diabetic complications. In the present study we used the mev-1 mutant of the nematode Caenorhabditis elegans fed on a high glucose concentration in liquid media as a diabetes model and tested the effects of carnitine supplementation on their survival under heat-stress. Carnitine at 100 μM completely prevented the survival reduction that was caused by the application of 10 mM glucose. RNA-interference for sir-2.1, a candidate genes mediating the effects of carnitine revealed no contribution of the sirtuin for the rescue of survival. Under daf-12 RNAi rescue of survival by carnitine was abolished. RNA-interference for γ-butyrobetaine hydroxylase 2, encoding the key enzyme for carnitine biosynthesis did neither increase glucose toxicity nor prevent the rescue of survival by carnitine, suggesting that the effects of carnitine supplementation on carnitine levels were significant. Finally, it was demonstrated that neither the amount of lysosomes nor the proteasomal activity were increased by carnitine, excluding that protein degradation pathways, such as autophagy or proteasomal degradation, are involved in the protective carnitine effects. In conclusion, carnitine supplementation prevents the reduction of survival caused by glucose in C. elegans in dependence on a nuclear hormone receptor which displays high homologies to the vertebrate peroxisomal proliferator activated receptors. - Highlights: • Carnitine protects from glucose-induced reduction of stress-resistance. • Carnitine acts via the PPAR homolog DAF-12 on glucose toxicity. • Carnitine protects from glucose toxicity independent of protein degradation.

  2. 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.

  3. 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.

  4. 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...

  5. Transcriptional coactivator p300 regulates glucose-induced gene expression in endothelial cells.

    Science.gov (United States)

    Chen, Shali; Feng, Biao; George, Biju; Chakrabarti, Rana; Chen, Megan; Chakrabarti, Subrata

    2010-01-01

    Sustained hyperglycemia in diabetes causes alteration of a large number of transcription factors and mRNA transcripts, leading to tissue damage. We investigated whether p300, a transcriptional coactivator with histone acetyl transferase activity, regulates glucose-induced activation of transcription factors and subsequent upregulation of vasoactive factors and extracellular matrix (ECM) proteins in human umbilical vein endothelial cells (HUVECs). HUVECs were incubated in varied glucose concentrations and were studied after p300 small interfering RNA (siRNA) transfection, p300 overexpression, or incubation with the p300 inhibitor curcumin. Histone H2AX phosphorylation and lysine acetylation were examined for oxidative DNA damage and p300 activation. Screening for transcription factors was performed with the Luminex system. Alterations of selected transcription factors were validated. mRNA expression of p300, endothelin-1 (ET-1), vascular endothelial growth factor (VEGF), and fibronectin (FN) and its splice variant EDB(+)FN and FN protein production were analyzed. HUVECs in 25 mmol/l glucose showed increased p300 production accompanied by increased binding of p300 to ET-1 and FN promoters, augmented histone acetylation, H2AX phosphorylation, activation of multiple transcription factors, and increased mRNA expression of vasoactive factors and ECM proteins. p300 overexpression showed a glucose-like effect on the mRNA expression of ET-1, VEGF, and FN. Furthermore, siRNA-mediated p300 blockade or chemical inhibitor of p300 prevented such glucose-induced changes. Similar mRNA upregulation was also seen in the organ culture of vascular tissues, which was prevented by p300 siRNA transfection. Data from these studies suggest that glucose-induced p300 upregulation is an important upstream epigenetic mechanism regulating gene expression of vasoactive factors and ECM proteins in endothelial cells and is a potential therapeutic target for diabetic complications.

  6. Adiponectin increases glucose-induced insulin secretion through the activation of lipid oxidation.

    Science.gov (United States)

    Patané, G; Caporarello, N; Marchetti, P; Parrino, C; Sudano, D; Marselli, L; Vigneri, R; Frittitta, L

    2013-12-01

    The expression of adiponectin receptors has been demonstrated in human and rat pancreatic beta cells, where globular (g) adiponectin rescues rat beta cells from cytokine and fatty acid-induced apoptosis. The aim of our study was to evaluate whether adiponectin has a direct effect on insulin secretion and the metabolic pathways involved. Purified human pancreatic islets and rat beta cells (INS-1E) were exposed (1 h) to g-adiponectin, and glucose-induced insulin secretion was measured. A significant increase in glucose-induced insulin secretion was observed in the presence of g-adiponectin (1 nmol/l) with respect to control cells in both human pancreatic islets (n = 5, p < 0.05) and INS-1E cells (n = 5, p < 0.001). The effect of globular adiponectin on insulin secretion was independent of AMP-dependent protein kinase (AMPK) activation or glucose oxidation. In contrast, g-adiponectin significantly increased oleate oxidation (n = 5, p < 0.05), and the effect of g-adiponectin (p < 0.001) on insulin secretion by INS-1E was significantly reduced in the presence of etomoxir (1 μmol/l), an inhibitor of fatty acid beta oxidation. g-Adiponectin potentiates glucose-induced insulin secretion in both human pancreatic islets and rat beta cells via an AMPK independent pathway. Increased fatty acid oxidation rather than augmented glucose oxidation is the mechanism responsible. Overall, our data indicate that, in addition to its anti-apoptotic action, g-adiponectin has another direct effect on beta cells by potentiating insulin secretion. Adiponectin, therefore, in addition to its well-known effect on insulin sensitivity, has important effects at the pancreatic level.

  7. Highly reflective reasoners show no signs of belief inhibition.

    Science.gov (United States)

    Svedholm-Häkkinen, Annika M

    2015-01-01

    The processes underlying individual differences in reasoning performance are not entirely understood. What do people who do well on reasoning tasks where beliefs and logic conflict do differently from other people? Because abundant evidence shows that even poorer reasoners detect these conflicts, it has been suggested that individual differences in reasoning performance arise from inhibition failures later in the reasoning process. The present paper argues that a minority of highly skilled reasoners may deviate from this general reasoning process from an early stage. Two studies investigated signs of belief inhibition using a lexical access paradigm (Study 1) and a negative priming paradigm (Study 2). Study 1 showed that while other people exhibited signs of belief inhibition following a belief-logic conflict, people with the highest disposition for cognitive reflection did not. In Study 2, this finding was replicated and similar results were also obtained when comparing groups with higher and lower general cognitive ability. Two possible explanations are discussed. The reasoners with a highly reflective cognitive style or high general cognitive ability may have engaged and inhibited belief processing but if so, they may have been exceptionally efficient at recovering from it, wherefore no belief inhibition effects were found. An alternative account is that these reasoners started Type 2 processing directly, without first engaging in and then inhibiting belief-based processing. Under either explanation, the results indicate that individual differences in reasoning may partly arise from differences that occur early in the reasoning process.

  8. 促红细胞生成素对高糖诱导人肾小球系膜细胞纤维化的影响及其机制研究%Effect of Erythropoietin on High Glucose -induced Fibrosis of Human Kidney Mesangial Cells and Its Possible Mechanism

    Institute of Scientific and Technical Information of China (English)

    柯本; 吴险峰; 陈艳霞; 房向东

    2015-01-01

    of CTGF and Collagen Ⅳat 24 h and the levels of IL-6 and TNF-αat 24 h and 48 h;20 U/ml EPO intervention group and Rho kinase inhibitor group were lower ( P<0.05) than 10 U/ml EPO intervention group in the levels of CTGF and Collagen Ⅳat 24 h and the levels of IL-6 and TNF-αat 24 h and 48 h.At 24 h, 48 h and 72 h, high glucose induction group , EPO control group , 5 U/ml EPO intervention group , 10 U/ml EPO intervention group and 20 U/ml EPO intervention group were higher (P<0.05) than blank control group in the OD value of MCs proliferation , and Rho kinase inhibitor group was lower ( P<0.05 ) than high glucose induction group in the OD value of MCs proliferation;the pairwise comparison among 5 U/ml EPO intervention group , 10 U/ml EPO intervention group and 20 U/ml EPO intervention group showed significant differences in the OD value of MCs proliferation ( P<0.05);in each of the three groups, the pairwise comparison of OD value of MCs proliferation among 24 h, 48 h and 72 h showed significant differences ( P<0.05) .Conclusion High glucose can inhibit the proliferation of MCs;high glucose can increase the expression of CTGF , Collagen Ⅳ, IL-6 and TNF-α, and EPO can inhibit the expression of CTGF , Collagen Ⅳ, IL-6 and TNF-αin MCs cultured by high glucose in certain concentration range and time range , facilitate proliferation and protect kidney.The mechanism may be related with the signal transduction pathway of RhoA /ROCK.

  9. Corrosion Inhibition of High Speed Steel by Biopolymer HPMC Derivatives

    Directory of Open Access Journals (Sweden)

    Shih-Chen Shi

    2016-07-01

    Full Text Available 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 promising anti-corrosion performance of HPMC and HPMCP. With increasing film thickness, both materials reveal improvement in corrosion inhibition. Moreover, because of a hydrophobic surface and lower moisture content, HPMCP shows better anti-corrosion performance than HPMCAS. The study is of certain importance for designing green corrosion inhibitors of high speed steel surfaces by the use of biopolymer derivatives.

  10. Cognitive Inhibition in Elderly High-Lethality Suicide Attempters

    Science.gov (United States)

    Richard-Devantoy, Stéphane; Szanto, Katalin; Butters, Meryl A.; Kalkus, Jan; Dombrovski, Alexandre Y.

    2014-01-01

    Background People who attempt suicide often display cognitive impairments, particularly poor cognitive control. Could poor cognitive control contribute to high suicide rates in old age? A component of cognitive control, cognitive inhibition – active suppression of task-irrelevant processing – is very sensitive to aging and has been linked to attempted suicide. We investigated cognitive inhibition in older high-lethality suicide attempters, closely resembling suicide victims, as well as low-lethality attempters, and control groups with and without depression and suicidal ideation. Methods 102 participants aged 60+ (17 psychiatrically healthy control subjects, 38 depressed control subjects, 16 suicide ideators, 14 low-lethality suicide attempters, and 17 high-lethality suicide attempters) underwent comprehensive clinical and cognitive assessments. They completed the Delis–Kaplan Executive Function System Color-Word Interference Test, a validated modification of the Stroop test. Results High-lethality suicide attempters demonstrated a distinct pattern of cognitive inhibition deficits. Compared to psychiatrically healthy control subjects and suicide ideators, high-lethality attempters took longer to complete inhibition trials, even after accounting for potential confounding factors (age, education, MMSE score, information processing speed, and accuracy). Compared to non-suicidal depressed and healthy control subjects, low-lethality suicide attempters committed more uncorrected errors; however, this difference was not specific to the inhibition condition. Conclusions Older suicide attempters are a cognitively heterogeneous group. Poor cognitive control in high-lethality attempters may undermine their ability to solve real-life problems, precipitating a catastrophic accumulation of stressors. Meanwhile, low-lethality attempters' poor performance may reflect a careless approach to the task or faulty monitoring. PMID:24816626

  11. GLUT2 and the incretin receptors are involved in glucose-induced incretin secretion

    DEFF Research Database (Denmark)

    Cani, Patrice D; Holst, Jens Juul; Drucker, Daniel J;

    2007-01-01

    content was reduced only in GIP and GLUT2 receptors knockout mice suggesting that this impairment could contribute to the phenotype. Intestinal GIP content was similar in all mice studied. Furthermore, the impaired incretins secretion was associated with a reduced glucose-stimulated insulin secretion...... to those described for beta-cells, brain and hepatoportal sensors. We determined the role of GLUT2, GLP-1 or GIP receptors in glucose-induced incretins secretion, in the corresponding knockout mice. GLP-1 secretion was reduced in all mutant mice, while GIP secretion did not require GLUT2. Intestinal GLP-1...... and an impaired glucose tolerance in all mice. In conclusion, both incretins secretion depends on mechanisms involving their own receptors and GLP-1 further requires GLUT2....

  12. Impaired glucose-induced thermogenesis and arterial norepinephrine response persist after weight reduction in obese humans

    DEFF Research Database (Denmark)

    Astrup, A; Andersen, T; Christensen, N J;

    1990-01-01

    A reduced thermic response and an impaired activation of the sympathetic nervous system (SNS) has been reported after oral glucose in human obesity. It is, however, not known whether the reduced SNS activity returns to normal along with weight reduction. The thermic effect of glucose was lower...... in eight obese patients than in matched control subjects (1.7% vs 9.2%, p less than 0.002). The increase in arterial norepinephrine after glucose was also blunted in the obese patients. After a 30-kg weight loss their glucose and lipid profiles were markedly improved but the thermic effect of glucose...... was still lower than that of the control subjects (4.2%, p less than 0.001). The glucose-induced arterial norepinephrine response remained diminished in the reduced obese patients whereas the changes in plasma epinephrine were similar in all three groups. The results suggest that a defective SNS may...

  13. 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.

  14. 基于微流控芯片的高糖对模式生物线虫寿命影响及白藜芦醇苷保护性作用考察%Microdevice for the investigation of high-glucose induced lifespan and the protective effect of polydatin in C. elegans

    Institute of Scientific and Technical Information of China (English)

    朱国丽; 尹方超; 王丽; 张敏; 姜雷; 秦建华

    2016-01-01

    Caenorhabditis elegans( C. elegans)has been widely used as a model organism for biomedical research due to its sufficient homology with human at molecular or genomic level. In this work,we describe a microfluidic device not only to investigate the response of C. elegans including lifespan and oxidative stress,but also to evaluate the protective effect of polydatin induced by high-glucose condition. It was found that the mean lifespan of worms was signifi-cantly reduced and the oxidative stress protein GST-4 was increased in worms that are subjec-ted to high glucose. However,a certain dose of polydatin could weaken the increased oxidative stress induced by high-glucose and extend the lifespan,indicating the protective effect of poly-datin against the toxic of high-glucose. The established approach is simple to operate,easy for realtime imaging and multiparatemer evaluations in parallel,providing a potential platform for drug evaluation/screening in a high throughput format at single animal resolution.%线虫是一种经典的模式生物,在分子和基因水平上与人类具有高度同源性,目前已被广泛应用于生命科学领域.本文以微流控芯片为平台,以模式生物秀丽隐杆线虫为研究对象,在单个线虫操作的水平上探讨高糖对线虫寿命和氧化应激的影响,同时考察了白藜芦醇苷对高糖引起的线虫寿命及应激响应变化的保护性作用.结果表明,高糖会缩短线虫寿命并增强线虫的氧化应激蛋白 GST-4表达;而白藜芦醇苷会显著减弱高糖诱导的线虫应激反应并延长线虫寿命,表明白藜芦醇苷对高糖诱发的线虫应激反应具有保护性作用.本文所建立的单个线虫操控的微流控芯片可以为动物水平上治疗糖尿病的相关药物评价提供一种新的潜在平台.

  15. Leucine regulation of glucokinase and ATP synthase sensitizes glucose-induced insulin secretion in pancreatic beta-cells.

    Science.gov (United States)

    Yang, Jichun; Wong, Ryan K; Park, MieJung; Wu, Jianmei; Cook, Joshua R; York, David A; Deng, Shaoping; Markmann, James; Naji, Ali; Wolf, Bryan A; Gao, Zhiyong

    2006-01-01

    We have recently shown that leucine culture upregulates ATP synthase beta-subunit (ATPSbeta) and increases ATP level, cytosolic Ca(2+), and glucose-induced insulin secretion in rat islets. The aim is to test whether glucokinase expression is also affected in rat islets and its role in glucose sensitization during leucine culture. Leucine culture increased glucose-induced NAD(P)H level at 1 and 2 days but not at 1 week. The half-maximal effective concentration of the glucose response curve for NAD(P)H was left-shifted from 5-7 to 2-3 mmol/l. The effect was dose dependent and rapamycin insensitive. Leucine culture did not affect glyceraldehyde effects on NAD(P)H. Leucine pretreatment for 30 min had no effects on NAD(P)H levels. Leucine culture for 2 days also increased glucose-induced cytosolic Ca(2+) elevation, ATP level, and insulin secretion. Leucine increase of glucokinase mRNA levels occurred as early as day 1 and lasted through 1 week. That of ATPSbeta did not occur until day 2 and lasted through 1 week. Leucine effects on both mRNAs were dose dependent. The upregulation of both genes was confirmed by Western blotting. Leucine culture also increased glucose-induced insulin secretion, ATP level, glucokinase, and ATPSbeta levels of type 2 diabetic human islets. In conclusion, leucine culture upregulates glucokinase, which increases NAD(P)H level, and ATPSbeta, which increases oxidation of NADH and production of ATP. The combined upregulation of both genes increases glucose-induced cytosolic Ca(2+) and insulin secretion.

  16. Ghrelin enhances glucose-induced insulin secretion in scheduled meal-fed sheep.

    Science.gov (United States)

    Takahashi, H; Kurose, Y; Kobayashi, S; Sugino, T; Kojima, M; Kangawa, K; Hasegawa, Y; Terashima, Y

    2006-04-01

    The purpose of this study was to investigate the effects of physiologic levels of ghrelin on insulin secretion and insulin sensitivity (glucose disposal) in scheduled fed-sheep, using the hyperglycemic clamp and hyperinsulinemic euglycemic clamp respectively. Twelve castrated Suffolk rams (69.8 +/- 0.6 kg) were conditioned to be fed alfalfa hay cubes (2% of body weight) once a day. Three hours after the feeding, synthetic ovine ghrelin was intravenously administered to the animals at a rate of 0.025 and 0.05 mug/kg body weight (BW) per min for 3 h. Concomitantly, the hyperglycemic clamp or the hyperinsulinemic euglycemic clamp was carried out. In the hyperglycemic clamp, a target glucose concentration was clamped at 100 mg/100 ml above the initial level. In the hyperinsulinemic euglycemic clamp, insulin was intravenously administered to the animals for 3 h at a rate of 2 mU/kg BW per min. Basal glucose concentrations (44+/- 1 mg/dl) were maintained by variably infusing 100 mg/dl glucose solution. In both clamps, plasma ghrelin concentrations were dose-dependently elevated and maintained at a constant level within the physiologic range. Ghrelin infusions induced a significant (ANOVA; P ghrelin-infused animals. In the hyperinsulinemic euglycemic clamp, glucose infusion rate, an index of insulin sensitivity, was not affected by ghrelin infusion. In conclusion, the present study has demonstrated for the first time that ghrelin enhances glucose-induced insulin secretion in the ruminant animal.

  17. Glucose induces intestinal human UDP-glucuronosyltransferase (UGT) 1A1 to prevent neonatal hyperbilirubinemia.

    Science.gov (United States)

    Aoshima, Naoya; Fujie, Yoshiko; Itoh, Tomoo; Tukey, Robert H; Fujiwara, Ryoichi

    2014-09-11

    Inadequate calorie intake or starvation has been suggested as a cause of neonatal jaundice, which can further cause permanent brain damage, kernicterus. This study experimentally investigated whether additional glucose treatments induce the bilirubin-metabolizing enzyme--UDP-glucuronosyltransferase (UGT) 1A1--to prevent the onset of neonatal hyperbilirubinemia. Neonatal humanized UGT1 (hUGT1) mice physiologically develop jaundice. In this study, UGT1A1 expression levels were determined in the liver and small intestine of neonatal hUGT1 mice that were orally treated with glucose. In the hUGT1 mice, glucose induced UGT1A1 in the small intestine, while it did not affect the expression of UGT1A1 in the liver. UGT1A1 was also induced in the human intestinal Caco-2 cells when the cells were cultured in the presence of glucose. Luciferase assays demonstrated that not only the proximal region (-1300/-7) of the UGT1A1 promoter, but also distal region (-6500/-4050) were responsible for the induction of UGT1A1 in the intestinal cells. Adequate calorie intake would lead to the sufficient expression of UGT1A1 in the small intestine to reduce serum bilirubin levels. Supplemental treatment of newborns with glucose solution can be a convenient and efficient method to treat neonatal jaundice while allowing continuous breastfeeding.

  18. High resolution spectroscopy reveals fibrillation inhibition pathways of insulin

    Science.gov (United States)

    Deckert-Gaudig, Tanja; Deckert, Volker

    2016-12-01

    Fibril formation implies the conversion of a protein’s native secondary structure and is associated with several neurodegenerative diseases. A better understanding of fibrillation inhibition and fibril dissection requires nanoscale molecular characterization of amyloid structures involved. Tip-enhanced Raman scattering (TERS) has already been used to chemically analyze amyloid fibrils on a sub-protein unit basis. Here, TERS in combination with atomic force microscopy (AFM), and conventional Raman spectroscopy characterizes insulin assemblies generated during inhibition and dissection experiments in the presence of benzonitrile, dimethylsulfoxide, quercetin, and β-carotene. The AFM topography indicates formation of filamentous or bead-like insulin self-assemblies. Information on the secondary structure of bulk samples and of single aggregates is obtained from standard Raman and TERS measurements. In particular the high spatial resolution of TERS reveals the surface conformations associated with the specific agents. The insulin aggregates formed under different inhibition and dissection conditions can show a similar morphology but differ in their β-sheet structure content. This suggests different aggregation pathways where the prevention of the β-sheet stacking of the peptide chains plays a major role. The presented approach is not limited to amyloid-related reasearch but can be readily applied to systems requiring extremely surface-sensitive characterization without the need of labels.

  19. A catechin-enriched green tea extract prevents glucose-induced survival reduction in Caenorhabditis elegans through sir-2.1 and uba-1 dependent hormesis.

    Science.gov (United States)

    Deusing, Dorothé Jenni; Winter, Sarah; Kler, Adolf; Kriesl, Erwin; Bonnländer, Bernd; Wenzel, Uwe; Fitzenberger, Elena

    2015-04-01

    Hyperglycemia is a hallmark of diabetes mellitus which leads to the onset of complications in the long term. Green tea through its high content of polyphenolic catechins, on the other hand, is suggested to prevent or at least delay such detrimental complications. In the present study we fed the nematode Caenorhabditis elegans on a liquid medium supplemented with 10mM glucose in the absence or presence of a catechin-enriched green tea extract (CEGTE). After exposure of young adults for 48h survival was subsequently measured under heat stress at 37°C. Whereas CEGTE at 0.01% did not affect the survival of wild type nematodes, it completely reversed the glucose-induced survival reduction. Those effects were not achieved through the monomeric catechins included in CEGTE. RNA interference (RNAi) for sir-2.1 not only prevented the survival extension by CEGTE under simultaneous glucose exposure but also caused a further reduction of survival. Likewise, the knockdown of uba-1, encoding the only E1-ubiquitin-activating enzyme in C. elegans, proved that UBA-1 is essential for the survival extension by CEGTE and that its loss of function changes CEGTE from a survival extending into a survival reducing extract. Stimulation of the proteasome by CEGTE was finally proven through measurements of the proteolytic cleavage of a fluorogenic peptide substrate. To conclude, our studies provide evidence that CEGTE reverses glucose-induced damage in C. elegans through activation of adaptive responses mediated by SIR-2.1 and proteasomal degradation. The hormetic mode of action is revealed by a reduction of survival once the adaptive processes were blocked.

  20. Effect of (-)-epigallocatechin-3-gallate on glucose-induced human serum albumin glycation.

    Science.gov (United States)

    Li, M; Hagerman, A E

    2015-01-01

    (-)-Epigallocatechin-3-gallate (EGCg) is a naturally occurring polyphenol found in plant-based foods and beverages such as green tea. Although EGCg can eliminate carbonyl species produced by glucose autoxidation and thus can inhibit protein glycation, it is also reported to be a pro-oxidant that stimulates protein glycation in vitro. To better understand the balance between antioxidant and pro-oxidant features of EGCg, we evaluated EGCg-mediated bioactivities in a human serum albumin (HSA)/glucose model by varying three different parameters (glucose level, EGCg concentration, and time of exposure to EGCg). Measurements of glycation-induced fluorescence, protein carbonyls, and electrophoretic mobility showed that the level of HSA glycation was positively related to the glucose level over the range 10-100 mM during a 21-day incubation at 37°C and pH: 7.4. Under mild glycemic pressure (10 mM), long exposure to EGCg enhanced HSA glycation, while brief exposure to low concentrations of EGCg did not. Under high glycemic pressure (100 mM glucose), long exposure to EGCg inhibited glycation. For the first time we showed that brief exposure to EGCg reversed glycation-induced fluorescence, indicating a restorative effect. In conclusion, our research identified glucose level, EGCg concentration, and time of exposure as critical factors dictating EGCg bioactivities in HSA glycation. EGCg did not affect HSA glycation under normal physiological conditions but had a potential therapeutic effect on HSA severely damaged by glycation.

  1. 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.

  2. High-throughput mass spectrometric cytochrome P450 inhibition screening.

    Science.gov (United States)

    Lim, Kheng B; Ozbal, Can C; Kassel, Daniel B

    2013-01-01

    We describe here a high-throughput assay to support rapid evaluation of drug discovery compounds for possible drug-drug interaction (DDI). Each compound is evaluated for its DDI potential by incubating over a range of eight concentrations and against a panel of six cytochrome P450 (CYP) enzymes: 1A2, 2C8, 2C9, 2C19, 2D6, and 3A4. The method utilizes automated liquid handling for sample preparation, and online solid-phase extraction/tandem mass spectrometry (SPE/MS/MS) for sample analyses. The system is capable of generating two 96-well assay plates in 30 min, and completes the data acquisition and analysis of both plates in about 30 min. Many laboratories that perform the CYP inhibition screening automate only part of the processes leaving a throughput bottleneck within the workflow. The protocols described in this chapter are aimed to streamline the entire process from assay to data acquisition and processing by incorporating automation and utilizing high-precision instrument to maximize throughput and minimize bottleneck.

  3. Glucose-induced glucagon-like Peptide 1 secretion is deficient in patients with non-alcoholic fatty liver disease.

    Directory of Open Access Journals (Sweden)

    Christine Bernsmeier

    Full Text Available BACKGROUND & AIMS: The incretins glucagon-like peptide-1 (GLP-1 and glucose-dependent insulinotropic polypeptide (GIP are gastrointestinal peptide hormones regulating postprandial insulin release from pancreatic β-cells. GLP-1 agonism is a treatment strategy in Type 2 diabetes and is evaluated in Non-alcoholic fatty liver disease (NAFLD. However, the role of incretins in its pathophysiology is insufficiently understood. Studies in mice suggest improvement of hepatic steatosis by GLP-1 agonism. We determined the secretion of incretins after oral glucose administration in non-diabetic NAFLD patients. METHODS: N=52 patients (n=16 NAFLD and n=36 Non-alcoholic steatohepatitis (NASH patients and n=50 matched healthy controls were included. Standardized oral glucose tolerance test was performed. Glucose, insulin, glucagon, GLP-1 and GIP plasma levels were measured sequentially for 120 minutes after glucose administration. RESULTS: Glucose induced GLP-1 secretion was significantly decreased in patients compared to controls (p<0.001. In contrast, GIP secretion was unchanged. There was no difference in GLP-1 and GIP secretion between NAFLD and NASH subgroups. All patients were insulin resistant, however HOMA2-IR was highest in the NASH subgroup. Fasting and glucose-induced insulin secretion was higher in NAFLD and NASH compared to controls, while the glucose lowering effect was diminished. Concomitantly, fasting glucagon secretion was significantly elevated in NAFLD and NASH. CONCLUSIONS: Glucose-induced GLP-1 secretion is deficient in patients with NAFLD and NASH. GIP secretion is contrarily preserved. Insulin resistance, with hyperinsulinemia and hyperglucagonemia, is present in all patients, and is more severe in NASH compared to NAFLD. These pathophysiologic findings endorse the current evaluation of GLP-1 agonism for the treatment of NAFLD.

  4. Potentiation of glucose-induced insulin release in islets by desHis1[Glu9]glucagon amide

    DEFF Research Database (Denmark)

    Kofod, Hans; Unson, C G; Merrifield, R B

    1988-01-01

    Glucagon and secretin and some of their hybrid analogs potentiate glucose-induced release of insulin from isolated mouse pancreatic islets. It was recently shown that the synthetic glucagon analog, desHis1[Glu9]glucagon amide, does not stimulate the formation of cyclic adenosine monophosphate...... in the rat hepatocyte membrane, but binds well to the glucagon receptor and is a good competitive antagonist of glucagon. In the present study the effect of this analog on isolated islets was examined. desHis1-[Glu9]glucagon amide at 3 x 10(-7) M, in the presence of 0.01 M D-glucose, increased the release...

  5. 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.

  6. Effects of the LIPE C-60G Polymorphism on Changes of Plasma Lipids and Glucose Induced by a High-carbohydrate Diet in Healthy Youth%激素敏感性脂肪酶基因C-60G多态性对高糖膳食诱导的健康青年血浆糖脂代谢指标变化的影响

    Institute of Scientific and Technical Information of China (English)

    李元昊; 龚仁蓉; 山本真衣; 姜喆; 樊梅; 方定志

    2011-01-01

    energy restriction.Plasma lipid profiles, glucose, insulin, homeostasis model assessment for insulin resistance (HOMA-IR) and body mass index (BMI) at baseline, before and after the highCHO diets as well as the LIPE C-60G polymorphism were analyzed.Results The females with the CC genotype had significantly higher levels of high-density lipoprotein cholesterol (HDL-C) ( P < 0.01, P < 0.05 ) and apolipoprotein A-Ⅰ(apo A- Ⅰ ) (P<0.01, P<0.01) than the males with the same genotype both before and after the high-CHO diet.After the high-CHO diet, only the females with the CC genotype had significantly higher levels of total cholesterol (TC) (P<0.01) and low-density lipoprotein cholesterol (LDL-C) (P<0.05) than their male counterparts.Compared with those before the high-CHO diet, the males with the CC genotype had significantly lower levels of BMI (P<0.05), TC (P<0.01) and LDL-C (P<0.01), but significantly higher levels of HDL-C (P<0.01) and apo A-Ⅰ (P<0.05) after the high-CHO diet.The males with the CG genotype experienced significant decreases of BMI (P<0.05) and TC (P<0.01).The females with the CC genotype experienced significant decreases of TC (P<0.01) and LDL-C (P<0.01) but significant increases of triglyceride (TG) (P<0.01) and insulin (P<0.05).The females with the CG genotype experienced a significant decrease of TC (P<0.05) but a significant increase of TG (P<0.05).Conclusion LIPE C-60G variation can inhibit the decrease of LDL-C and the increases of HDL-C and apo A- Ⅰ in young healthy males induced by the high-CHO diet, and can inhibit the decrease of LDL-C and the increase of insulin in young healthy females induced by the same diet.

  7. Disruption of overshadowing and latent inhibition in high schizotypy individuals.

    Science.gov (United States)

    Granger, K T; Prados, J; Young, A M J

    2012-07-15

    Deficits in selective attention are seen in positively symptomatic schizophrenia sufferers, and in normal people displaying schizotypal traits. We investigated the relationship between selective attention and schizotypy in undergraduate students, by comparing participants' performance in two models of selective attention, overshadowing and latent inhibition, with psychoticism scores derived from the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE). Using a novel within-subject overshadowing task, we showed that the unusual experiences dimension of schizotypy, but not the other three O-LIFE dimensions, was negatively related to overshadowing score. We also replicated findings that the unusual experiences dimension of schizotypy was negatively related to latent inhibition score. These experiments provide evidence that selective attention is disrupted in normal individuals showing traits relating to positive-like schizophrenic symptoms, and has implications for interpreting selective attention deficits measured in schizophrenia patients.

  8. 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.

  9. The mitochondrial Ca2+ uniporter MCU is essential for glucose-induced ATP increases in pancreatic β-cells.

    Directory of Open Access Journals (Sweden)

    Andrei I Tarasov

    Full Text Available Glucose induces insulin release from pancreatic β-cells by stimulating ATP synthesis, membrane depolarisation and Ca(2+ influx. As well as activating ATP-consuming processes, cytosolic Ca(2+ increases may also potentiate mitochondrial ATP synthesis. Until recently, the ability to study the role of mitochondrial Ca(2+ transport in glucose-stimulated insulin secretion has been hindered by the absence of suitable approaches either to suppress Ca(2+ uptake into these organelles, or to examine the impact on β-cell excitability. Here, we have combined patch-clamp electrophysiology with simultaneous real-time imaging of compartmentalised changes in Ca(2+ and ATP/ADP ratio in single primary mouse β-cells, using recombinant targeted (Pericam or Perceval, respectively as well as entrapped intracellular (Fura-Red, probes. Through shRNA-mediated silencing we show that the recently-identified mitochondrial Ca(2+ uniporter, MCU, is required for depolarisation-induced mitochondrial Ca(2+ increases, and for a sustained increase in cytosolic ATP/ADP ratio. By contrast, silencing of the mitochondrial Na(+-Ca(2+ exchanger NCLX affected the kinetics of glucose-induced changes in, but not steady state values of, cytosolic ATP/ADP. Exposure to gluco-lipotoxic conditions delayed both mitochondrial Ca(2+ uptake and cytosolic ATP/ADP ratio increases without affecting the expression of either gene. Mitochondrial Ca(2+ accumulation, mediated by MCU and modulated by NCLX, is thus required for normal glucose sensing by pancreatic β-cells, and becomes defective in conditions mimicking the diabetic milieu.

  10. The mitochondrial Ca2+ uniporter MCU is essential for glucose-induced ATP increases in pancreatic β-cells.

    Science.gov (United States)

    Tarasov, Andrei I; Semplici, Francesca; Ravier, Magalie A; Bellomo, Elisa A; Pullen, Timothy J; Gilon, Patrick; Sekler, Israel; Rizzuto, Rosario; Rutter, Guy A

    2012-01-01

    Glucose induces insulin release from pancreatic β-cells by stimulating ATP synthesis, membrane depolarisation and Ca(2+) influx. As well as activating ATP-consuming processes, cytosolic Ca(2+) increases may also potentiate mitochondrial ATP synthesis. Until recently, the ability to study the role of mitochondrial Ca(2+) transport in glucose-stimulated insulin secretion has been hindered by the absence of suitable approaches either to suppress Ca(2+) uptake into these organelles, or to examine the impact on β-cell excitability. Here, we have combined patch-clamp electrophysiology with simultaneous real-time imaging of compartmentalised changes in Ca(2+) and ATP/ADP ratio in single primary mouse β-cells, using recombinant targeted (Pericam or Perceval, respectively) as well as entrapped intracellular (Fura-Red), probes. Through shRNA-mediated silencing we show that the recently-identified mitochondrial Ca(2+) uniporter, MCU, is required for depolarisation-induced mitochondrial Ca(2+) increases, and for a sustained increase in cytosolic ATP/ADP ratio. By contrast, silencing of the mitochondrial Na(+)-Ca(2+) exchanger NCLX affected the kinetics of glucose-induced changes in, but not steady state values of, cytosolic ATP/ADP. Exposure to gluco-lipotoxic conditions delayed both mitochondrial Ca(2+) uptake and cytosolic ATP/ADP ratio increases without affecting the expression of either gene. Mitochondrial Ca(2+) accumulation, mediated by MCU and modulated by NCLX, is thus required for normal glucose sensing by pancreatic β-cells, and becomes defective in conditions mimicking the diabetic milieu.

  11. 柚皮苷抑制高糖诱导的脐静脉内皮细胞与单核细胞的粘附作用%Naringin inhibits monocyte adhesion to high glucose-induced human umbilical vein endothelial cells

    Institute of Scientific and Technical Information of China (English)

    熊莺; 王广发; 张俊艳; 吴少瑜; 徐伟; 张嘉杰; 吴曙光; 饶进军

    2010-01-01

    目的 研究柚皮苷对高糖诱导的脐静脉内皮细胞(HUVECs)与单核细胞的粘附的抑制作用及机制.方法 分离培养HUVECs后,采用不同剂量的柚皮苷预处理HUVECs,然后高糖诱导HUVECs;加入荧光染料标记单核细胞系THP-1细胞与HUVECs共同孵育,荧光显微镜下观察HUVECs与单核细胞的粘附作用并拍照,比较粘附密度;提取总蛋白后,Westem blotting检测处理后HUVECs粘附分子的表达;荧光染料结合法检测处理后HUVECs活性氧的产生;提取处理的脐静脉内皮细胞核蛋白后,Western blotting检测核因子-κB在核内的量.结果 高糖诱导HUVECs与单核细胞的粘附,柚皮苷可显著抑制高糖诱导的HUVECs与单核细胞的粘附.柚皮苷抑制高糖诱导的HUVECs细胞间粘附分子和血管内皮细胞粘附分子的表达,柚皮苷抑制高糖诱导的HUVECs活性氧产生,柚皮苷抑制高糖诱导的HUVECs核因子-κB p65活化.结论柚皮苷可能通过抑制高糖诱导的HUVECs活性氧产生,从而抑制核因子-κB的活化,进一步抑制细胞间粘附分子和血管内皮细胞粘附分子的表达,影响HUVECs与THP-1细胞的粘附,从而抑制高糖诱导的血管炎症.

  12. Parathyroid hormone inhibits TGF-β/Smad signaling and extracellular matrix proteins upregulation in rat mesangial cells.

    Science.gov (United States)

    Peng, Fang-Fang; Xiao, Ze-Ling; Chen, Hong-Min; Chen, Yan; Zhou, Jian; Yu, Hong; Zhang, Bai-Fang

    2016-09-23

    Accumulation of glomerular matrix is a hallmark of diabetic nephropathy. TGF-β1 is a major cytokine mediating the production of various extracellular matrix (ECM) proteins. The aim of this study is to elucidate the effect of parathyroid hormone (PTH) on TGF-β1 and high glucose-induced upregulation of ECM proteins in primary mesangial cells from Sprague-Dawley rat. The results showed that PTH pretreatment prevented TGF-β1 and high glucose-induced Smad2/3 phosphorylation and consequent upregulation of fibronectin and type IV collagen within 4 h. The inhibitory effect of PTH is due to PTH1R activation, because knocking down PTH 1 receptor (PTH1R) by RNA interference reversed the inhibitory effect of PTH on TGF-β1 and high glucose-induced Smad2/3 phosphorylation and ECM upregulation. Furthermore, it is found that PTH1R associated with TGF-β type II receptor (TβR II) and both receptors internalized into the cytoplasm when mesangial cells were stimulated with PTH alone. The internalization of TβR II might reduce the amount of membrane TβR II, attenuate the sensitivity of mesangial cells to TGF-β1, and therefore inhibit Smad activation and ECM upregulation induced by TGF-β1 and high glucose. Further studies are needed to know whether the endocytic receptors are to be degraded or recycled, and evaluate the role of PTH in TGF-β1 signaling more comprehensively.

  13. Glucose-induced posttranslational activation of protein phosphatases PP2A and PP1 in yeast

    Institute of Scientific and Technical Information of China (English)

    Dries Castermans; Ils Somers; Johan Kriel; Wendy Louwet; Stefaan Wera; Matthias Versele; Veerle Janssens; Johan M Thevelein

    2012-01-01

    The protein phosphatases PP2A and PP1 are major regulators of a variety of cellular processes in yeast and other eukaryotes.Here,we reveal that both enzymes are direct targets of glucose sensing.Addition of glucose to glucosedeprived yeast cells triggered rapid posttranslational activation of both PP2A and PP1.Glucose activation of PP2A is controlled by regulatory subunits Rts1,Cdc55,Rrd1 and Rrd2.It is associated with rapid carboxymethylation of the catalytic subnnits,which is necessary but not sufficient for activation.Glucose activation of PP1 was fully dependent on regulatory subunits Reg1 and Shp1.Absence of Gac1,GIc8,Reg2 or Red1 partially reduced activation while Pig1 and Pig2 inhibited activation.Full activation of PP2A and PP1 was also dependent on subunits classically considered to belong to the other phosphatase.PP2A activation was dependent on PP1 subunits Reg1 and Shpl while PP1 activation was dependent on PP2A subunit Rts1.Rts1 interacted with both Pph21 and Glc7 under different conditions and these interactions were Regl dependent.Regl-GIc7 interaction is responsible for PP1 involvement in the main glucose repression pathway and we show that deletion of Shpl also causes strong derepression of the invertase gene SUC2.Deletion of the PP2A subunits Pph21 and Pph22,Rrd1 and Rrd2,specifically enhanced the derepression level of SUC2,indicating that PP2A counteracts SUC2 derepression.Interestingly,the effect of the regulatory subunit Rtsl was consistent with its role as a subunit of both PP2A and PP1,affecting derepression and repression of SUC2,respectively.We also show that abolished phosphatase activation,except by reg1A,does not completely block Snf1 dephosphorylation after addition of glucose.Finally,we show that glucose activation of the cAMP-PKA (protein kinase A)pathway is required for glucose activation of both PP2A and PP1.Our results provide novel insight into the complex regulatory role of these two major protein phosphatases in glucose

  14. Impaired glucose-induced thermogenesis in skeletal muscle in obesity. The role of the sympathoadrenal system

    DEFF Research Database (Denmark)

    Astrup, A; Andersen, T; Henriksen, O

    1987-01-01

    From a 7-day food recording in 29 morbidly obese patients two groups of six patients each were selected: a high-energy-intake group (HEI) and a low-energy-intake group (LEI). The groups were otherwise comparable. Five lean subjects served as controls for some observations. Oral glucose tolerance...

  15. Role of Nodal-PITX2C signaling pathway in glucose-induced cardiomyocyte hypertrophy.

    Science.gov (United States)

    Su, Dongmei; Jing, Sun; Guan, Lina; Li, Qian; Zhang, Huiling; Gao, Xiaobo; Ma, Xu

    2014-06-01

    Pathological cardiac hypertrophy is a major cause of morbidity and mortality in cardiovascular disease. Recent studies have shown that cardiomyocytes, in response to high glucose (HG) stimuli, undergo hypertrophic growth. While much work still needs to be done to elucidate this important mechanism of hypertrophy, previous works have showed that some pathways or genes play important roles in hypertrophy. In this study, we showed that sublethal concentrations of glucose (25 mmol/L) could induce cardiomyocyte hypertrophy with an increase in the cellular surface area and the upregulation of the atrial natriuretic peptide (ANP) gene, a hypertrophic marker. High glucose (HG) treatments resulted in the upregulation of the Nodal gene, which is under-expressed in cardiomyocytes. We also determined that the knockdown of the Nodal gene resisted HG-induced cardiomyocyte hypertrophy. The overexpression of Nodal was able to induce hypertrophy in cardiomyocytes, which was associated with the upregulation of the PITX2C gene. We also showed that increases in the PITX2C expression, in response to Nodal, were mediated by the Smad4 signaling pathway. This study is highly relevant to the understanding of the effects of the Nodal-PITX2C pathway on HG-induced cardiomyocyte hypertrophy, as well as the related molecular mechanisms.

  16. Irisin prevents high glucose-induced human umbilical vein endothelial cell apoptosis via phosphatidylinositol-3-kinase-protein kinase B-endothelial nitric oxide synthase signaling pathway%鸢尾素通过激活3-磷酸磷脂酰肌醇激酶-蛋白激酶B-内皮型一氧化氮合酶信号转导途径抗高糖诱导的人脐静脉内皮细胞凋亡

    Institute of Scientific and Technical Information of China (English)

    卢俊颜; 向光大; 梅稳; 刘敏; 向林; 董靖

    2015-01-01

    Objective To explore the effects of irisin on endothelial cells cultured with high glucose and the possible mechanism-involved. Methods Human umbilical vein endothelial cells (HUVECs) were pre⁃incubated with inhibitors against phosphatidylinositol⁃3⁃kinase (PI3K) (LY294002) or endothelial nitric oxide synthase(eNOS) (L⁃NAME) for 30 min before irisin was added, then divided into 6 groups: normal glucose (NG) group, high glucose (HG) group, high glucose+irisin (Irisin) group, high glucose+LY294002+irisin (LY) group, high glucose+L⁃NAME+irisin(L⁃NAME) group, high glucose+LY294002+L⁃NAME+irisin (LY+L⁃NAME) group, cultured for 48 h. Terminal deoxynucleotidyl transferase biotin⁃dUTP nick end labeling (TUNEL) staining was applied to identify the apoptotic endothelial cells. Reactive oxygen species assay kit and reverse transcription polymerase chain reaction(RT⁃PCR) was used to determine the oxidative stress in HUVECs. The expression levels of protein kinase B(Akt), phospheralyted Akt(P-Akt), eNOS and phospheralyted eNOS(P-eNOS) were measured by Western blotting. Moreover, HUVECs were transfected with eNOS⁃siRNA, and cultured in high glucose and then divided into 4 groups:NG+Scr⁃siRNA group, HG+Scr⁃siRNA group, HG+Scr⁃siRNA+irisin group and HG+eNOS⁃siRNA+irisin group, cultured for 48 h. After treatment, the cells were double-stained with fluorescein isothiocyanate/propidium iodide (Annexin V⁃FITC/PI) and analyzed by flow cytometry. Data were compared using one⁃way analysis of variance (ANOVA). Results The apoptotic rate of HUVECs in HG group were significantly higher than that in NG group (25.6%± 3.2% vs 6.0%± 1.5%, t=-13.55, P<0.01), while it significantly decreased in Irisin group than that in HG group (19.8%± 2.3% vs 25.6%± 3.2%, t=-3.55, P<0.01). The apoptotic rate of HUVECs in LY, L⁃NAME and LY+L⁃NAME group were all significantly higher than that in Irisin group (t=-3.85,-5.19,-7.11, all P<0.01). After eNOS gene silencing in

  17. High functional load inhibits phonological contrast loss: a corpus study.

    Science.gov (United States)

    Wedel, Andrew; Kaplan, Abby; Jackson, Scott

    2013-08-01

    For nearly a century, linguists have suggested that diachronic merger is less likely between phonemes with a high functional load--that is, phonemes that distinguish many words in the language in question. However, limitations in data and computational power have made assessing this hypothesis difficult. Here we present the first larger-scale study of the functional load hypothesis, using data from sound changes in a diverse set of languages. Our results support the functional load hypothesis: phoneme pairs undergoing merger distinguish significantly fewer minimal pairs in the lexicon than unmerged phoneme pairs. Furthermore, we show that higher phoneme probability is positively correlated with merger, but that this effect is stronger for phonemes that distinguish no minimal pairs. Finally, within our dataset we find that minimal pair count and phoneme probability better predict merger than change in system entropy at the lexical or phoneme level.

  18. Effects of 5-aza-2' -deoxycytidine combined with trichostatin A on cell proliferation and PDX-1 methylation on high glucose-induced toxicity in pancreatic β cells%5-氮杂-2'-脱氧胞苷联合曲古霉素A对高糖诱导下胰岛β细胞的增殖及PDX-1甲基化的影响

    Institute of Scientific and Technical Information of China (English)

    张文静; 王利; 陈莉; 郭丽银; 赵娟; 邵菁; 王红祥

    2016-01-01

    目的:探讨高糖诱导下应用5-氮杂-2'-脱氧胞苷(5-Aza-dC)和曲古霉素A(TSA)对胰岛 β 细胞NIT-1细胞株增殖及PDX-1启动子区甲基化及其表达的影响.方法:胰岛β细胞株予33.3 mmol/L葡萄糖浓度处理后随机分为:空白对照(NC)组、高糖诱导(HG)组、5-Aza-dC干预组、TSA干预组、5-Aza-dC+TSA联合干预组,检测细胞增殖情况、胰岛素释放水平、PDX-1启动子区甲基化状态及其表达水平的变化.结果:5-Aza-dC和TSA单独或联合干预可增加NIT-1细胞增殖率和胰岛素分泌量,降低PDX-1启动子区甲基化产物,增加PDX-1 mRNA相对表达量,并且联合组比单药组效果更加明显(均P<0.05).结论:5-Aza-dC和TSA可以激活高糖诱导下失表达的PDX-1,进而恢复胰岛β细胞功能,两药联合具有协同效应.%Objective To investigate the effects of 5-aza-2'-deoxycytidine (5-Aza-dC) alone or combined with trichostatin A(TSA) on cell proliferation, promoter methylation and mRNA expression level of PDX-1 gene in pancreatic β cells induced by high glucose toxicity. Method NIT-1 cells were treated in vitro by high glucose (33.3 mmol/L), then divided into five groups, control group, HG grpup, 5-Aza-dC treatment group, TSA interfere group and 5-Aza-dC + TSA group. Proliferation of NIT-1 cells, insulin secretion, promoter methylation and mRNA expression of PDX-1 gene were detected respectively. Results 5-Aza-dC and TSA alone or in combination could promote cell proliferation and recover insulin secretion in NIT-1 cells , could also reduce PDX-1 gene methylation and enhance expression of PDX-1 mRNA. Compared with single-treatment group , combined group was significantly different (all P < 0.05). Conclusion 5-Aza-dC and TSA could activate the expression of PDX-1 and, then recover insulin secretion in NIT-1 cells induced by high glucose. Combination of them had synergistic effect.

  19. Central and peripheral contributions to dynamic changes in nucleus accumbens glucose induced by intravenous cocaine

    Directory of Open Access Journals (Sweden)

    Ken Taro Wakabayashi

    2015-02-01

    Full Text Available The pattern of neural, physiological and behavioral effects induced by cocaine is consistent with metabolic neural activation, yet direct attempts to evaluate central metabolic effects of this drug have produced controversial results. Here, we used enzyme-based glucose sensors coupled with high-speed amperometry in freely moving rats to examine how intravenous cocaine at a behaviorally active dose affects extracellular glucose levels in the nucleus accumbens (NAc, a critical structure within the motivation-reinforcement circuit. In drug-naive rats, cocaine induced a bimodal increase in glucose, with the first, ultra-fast phasic rise appearing during the injection (latency 6-8 s; ~50 µM or ~5% of baseline followed by a larger, more prolonged tonic elevation (~100 µM or 10% of baseline, peak ~15 min. While the rapid, phasic component of the glucose response remained stable following subsequent cocaine injections, the tonic component progressively decreased. Cocaine-methiodide, cocaine’s peripherally acting analog, induced an equally rapid and strong initial glucose rise, indicating cocaine’s action on peripheral neural substrates as its cause. However, this analog did not induce increases in either locomotion or tonic glucose, suggesting direct central mediation of these cocaine effects. Under systemic pharmacological blockade of dopamine transmission, both phasic and tonic components of the cocaine-induced glucose response were only slightly reduced, suggesting a significant role of non-dopamine mechanisms in cocaine-induced accumbal glucose influx. Hence, intravenous cocaine induces rapid, strong inflow of glucose into NAc extracellular space by involving both peripheral and central, non-dopamine drug actions, thus preventing a possible deficit resulting from enhanced glucose use by brain cells.

  20. Central and peripheral contributions to dynamic changes in nucleus accumbens glucose induced by intravenous cocaine

    Science.gov (United States)

    Wakabayashi, Ken T.; Kiyatkin, Eugene A.

    2015-01-01

    The pattern of neural, physiological and behavioral effects induced by cocaine is consistent with metabolic neural activation, yet direct attempts to evaluate central metabolic effects of this drug have produced controversial results. Here, we used enzyme-based glucose sensors coupled with high-speed amperometry in freely moving rats to examine how intravenous cocaine at a behaviorally active dose affects extracellular glucose levels in the nucleus accumbens (NAc), a critical structure within the motivation-reinforcement circuit. In drug-naive rats, cocaine induced a bimodal increase in glucose, with the first, ultra-fast phasic rise appearing during the injection (latency 6–8 s; ~50 μM or ~5% of baseline) followed by a larger, more prolonged tonic elevation (~100 μM or 10% of baseline, peak ~15 min). While the rapid, phasic component of the glucose response remained stable following subsequent cocaine injections, the tonic component progressively decreased. Cocaine-methiodide, cocaine's peripherally acting analog, induced an equally rapid and strong initial glucose rise, indicating cocaine's action on peripheral neural substrates as its cause. However, this analog did not induce increases in either locomotion or tonic glucose, suggesting direct central mediation of these cocaine effects. Under systemic pharmacological blockade of dopamine transmission, both phasic and tonic components of the cocaine-induced glucose response were only slightly reduced, suggesting a significant role of non-dopamine mechanisms in cocaine-induced accumbal glucose influx. Hence, intravenous cocaine induces rapid, strong inflow of glucose into NAc extracellular space by involving both peripheral and central, non-dopamine drug actions, thus preventing a possible deficit resulting from enhanced glucose use by brain cells. PMID:25729349

  1. Ginseng Extracts Restore High-Glucose Induced Vascular Dysfunctions by Altering Triglyceride Metabolism and Downregulation of Atherosclerosis-Related Genes

    Directory of Open Access Journals (Sweden)

    Gabriel Hoi-huen Chan

    2013-01-01

    Full Text Available The king of herbs, Panax ginseng, has been used widely as a therapeutic agent vis-à-vis its active pharmacological and physiological effects. Based on Chinese pharmacopeia Ben Cao Gang Mu and various pieces of literature, Panax ginseng was believed to exert active vascular protective effects through its antiobesity and anti-inflammation properties. We investigated the vascular protective effects of ginseng by administrating ginseng extracts to rats after the induction of diabetes. We found that Panax ginseng can restore diabetes-induced impaired vasorelaxation and can reduce serum triglyceride but not cholesterol level in the diabetic rats. The ginseng extracts also suppressed the expression of atherosclerosis-related genes and altered the expression of lipid-related genes. The results provide evidence that Panax ginseng improves vascular dysfunction induced by diabetes and the protective effects may possibly be due to the downregulation of atherosclerosis-related genes and altered lipid metabolism, which help to restore normal endothelium functions.

  2. The possible link between high glucose-induced PKCβ expression and the appearance of GLP-1 resistance in endothelial cells

    OpenAIRE

    De Nigris,Valeria

    2015-01-01

    [spa] INTRODUCCIÓN. Se ha demostrado que el Glucagon-like peptide-1 (GLP-1) tiene un efecto protector sobre las células endoteliales. GLP-1 mejora la función endotelial en la diabetes, sin embargo los mecanismos subyacentes a los efectos protectores de GLP-1 aún no han sido completamente aclarada. Además, se ha propuesto que el GLP-1 podría restaurar la función del retículo endoplasmático (ER), cuyo estés es inducido en condiciones de alta glucosa. Evidencias recientes afirman que existe una ...

  3. Berberine ameliorates experimental diabetes-induced renal inflammation and fibronectin by inhibiting the activation of RhoA/ROCK signaling.

    Science.gov (United States)

    Xie, Xi; Chang, Xiuting; Chen, Lei; Huang, Kaipeng; Huang, Juan; Wang, Shaogui; Shen, Xiaoyan; Liu, Peiqing; Huang, Heqing

    2013-12-05

    The accumulation of glomerular extracellular matrix proteins, especially fibronectin (FN), is a critical pathological characteristic of diabetic renal fibrosis. Inflammation mediated by nuclear factor-κB (NF-κB) plays a critical role in the pathogenesis of diabetic nephropathy (DN). RhoA/ROCK signaling is responsible for FN accumulation and NF-κB activation. Berberine (BBR) treatment significantly inhibited renal inflammation and thus improved renal damage in diabetes. Here, we study whether BBR inhibits FN accumulation and NF-κB activation by inhibiting RhoA/ROCK signaling and the underlying mechanisms involved. Results showed that BBR effectively inhibited RhoA/ROCK signaling activation in diabetic rat kidneys and high glucose-induced glomerular mesangial cells (GMCs) and simultaneously down-regulated NF-κB activity, which was accompanied by reduced intercellular adhesionmolecule-1, transforming growth factor-beta 1 and FN overproduction. Furthermore, we observed that BBR abrogated high glucose-mediated reactive oxygen species generation in GMCs. BBR and N-acetylcysteine inhibited RhoA/ROCK signaling activation in high glucose-exposed GMCs. Collectively, our data suggest that the renoprotective effect of BBR on DN partly depends on RhoA/ROCK inhibition. The anti-oxidative stress effect of BBR is responsible for RhoA/ROCK inhibition in DN.

  4. 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.

  5. Response inhibition and immediate arousal in children with high-functioning autism

    NARCIS (Netherlands)

    Raymaekers, Ruth; van der Meere, Jaap; Roeyers, Herbert

    2006-01-01

    The current study compared high-functioning children with autism (HFA) and a peer control group on an immediate arousal task measuring response inhibition. In one condition go stimuli were presented whereas in another condition a tone preceded the go stimulus. The tone caused an immediate arousal ef

  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. Mitigation of starch and glucose-induced postprandial glycemic excursion in rats by antioxidant-rich green-leafy vegetables′ juice

    Directory of Open Access Journals (Sweden)

    Ashok Kumar Tiwari

    2013-01-01

    Full Text Available Objective: Consumption of green-leafy vegetables is being advocated beneficial for type 2 diabetes mellitus individuals possibly because they are cost effective source of potent biological antioxidants. This research analyzed various phytochemicals, free radicals scavenging antioxidant potentials and starch digesting enzymes inhibitory activities in fresh juice of nine green-leafy vegetables. Furthermore, this study also investigated influence of these vegetables juice on starch and glucose induced postprandial glycemic load. Materials and Methods: Phytochemical constituents, in vitro free radicals scavenging antioxidant and enzymes inhibitory activities were evaluated applying various reported methods. Post-prandial glycemic excursion was induced in rats pretreated with vegetables juice by oral administration of starch and glucose. Results: All the leafy vegetables juice displayed potent free radicals scavenging activities. Juice of amaranthus, rumex, palak and raphanus displayed potential anti-oxidative property by reducing H 2 O 2 induced hemolysis in rats red blood cells RBCs. Ajwain and rumex juice showed pancreatic α-amylase inhibitory activity. Alternanthera, ajwain, methi, amaranthus and sowa leaves juice displayed intestinal α-glucosidase inhibitory activity. Juice of raphanus, ajwain and sowa significantly mitigated starch-induced postprandial glycemic load. Amaranthus leaves juice potently mitigated glucose-induced postprandial glycemic load and also reduced hemoglobin glycation induced by glucose in vitro. Conclusions: This investigation finds that juice of leafy vegetables is potent source of biological antioxidants. In addition, juice of raphanus, ajwain and sowa leaves possess capacity to mitigate starch induced postprandial glycemic burden and amaranthus leaves′ juice can reduce glucose induced postprandial glycemic excursion.

  8. High iron sequestrating bifidobacteria inhibit enteropathogen growth and adhesion to intestinal epithelial cells in vitro

    Directory of Open Access Journals (Sweden)

    Pamela Vazquez-Gutierrez

    2016-09-01

    Full Text Available The gut microbiota plays an important role in host health, in particular by its barrier effect and competition with exogenous pathogenic bacteria. In the present study, the competition of Bifidobacterium pseudolongum PV8-2 (Bp PV8-2 and Bifidobacterium kashiwanohense PV20-2 (Bk PV20-2, isolated from anemic infant gut microbiota and selected for their high iron sequestration properties was investigated against Salmonella Typhimurium (S. Typhi and Escherichia coli O157:H45 (EHEC by using co-culture tests and assays with intestinal cell lines. Single and co-cultures were carried out anaerobically in chemically semi-defined low iron (1.5 µM Fe medium (CSDLIM without and with added ferrous iron (30 µM Fe. Surface properties of the tested strains were measured by bacterial adhesion to solvent xylene, chloroform, ethyl acetate, and to extracellular matrix molecules, mucus II, collagen I, fibrinogen, fibronectin. HT29-MTX mucus-secreting intestinal cell cultures were used to study bifidobacteria competition, inhibition and displacement of the enteropatogens. During co-cultures in CSDLIM we observed strain-dependent inhibition of bifidobacterial strains on enteropathogens, independent of pH, organic acid production and supplemented iron. Bp PV8-2 significantly (P<0.05 inhibited S. Typhi N15 and EHEC after 24 h compared to single culture growth. In contrast Bk PV20-2 showed less inhibition on S. Typhi N15 than Bp PV8-2, and no inhibition on EHEC. Affinity for intestinal cell surface glycoproteins was strain-specific, with high affinity of Bp PV8-2 for mucin and Bk PV20-2 for fibronectin. Bk PV20-2 showed high adhesion potential (15.6 +/- 6.0 % to HT29-MTX cell layer compared to Bp PV8-2 (1.4 +/- 0.4 %. In competition, inhibition and displacement tests, Bp PV8-2 significantly (P<0.05 reduced S. Typhi N15 and EHEC adhesion, while Bk PV20-2 was only active on S. Typhi N15 adhesion. To conclude, bifidobacterial strains selected for their high iron binding

  9. A high-throughput screen for aggregation-based inhibition in a large compound library.

    Science.gov (United States)

    Feng, Brian Y; Simeonov, Anton; Jadhav, Ajit; Babaoglu, Kerim; Inglese, James; Shoichet, Brian K; Austin, Christopher P

    2007-05-17

    High-throughput screening (HTS) is the primary technique for new lead identification in drug discovery and chemical biology. Unfortunately, it is susceptible to false-positive hits. One common mechanism for such false-positives is the congregation of organic molecules into colloidal aggregates, which nonspecifically inhibit enzymes. To both evaluate the feasibility of large-scale identification of aggregate-based inhibition and quantify its prevalence among screening hits, we tested 70,563 molecules from the National Institutes of Health Chemical Genomics Center (NCGC) library for detergent-sensitive inhibition. Each molecule was screened in at least seven concentrations, such that dose-response curves were obtained for all molecules in the library. There were 1274 inhibitors identified in total, of which 1204 were unambiguously detergent-sensitive. We identified these as aggregate-based inhibitors. Thirty-one library molecules were independently purchased and retested in secondary low-throughput experiments; 29 of these were confirmed as either aggregators or nonaggregators, as appropriate. Finally, with the dose-response information collected for every compound, we could examine the correlation between aggregate-based inhibition and steep dose-response curves. Three key results emerge from this study: first, detergent-dependent identification of aggregate-based inhibition is feasible on the large scale. Second, 95% of the actives obtained in this screen are aggregate-based inhibitors. Third, aggregate-based inhibition is correlated with steep dose-response curves, although not absolutely. The results of this screen are being released publicly via the PubChem database.

  10. Tremorgenic indole alkaloids potently inhibit smooth muscle high-conductance calcium-activated potassium channels.

    Science.gov (United States)

    Knaus, H G; McManus, O B; Lee, S H; Schmalhofer, W A; Garcia-Calvo, M; Helms, L M; Sanchez, M; Giangiacomo, K; Reuben, J P; Smith, A B

    1994-05-17

    Tremorgenic indole alkaloids produce neurological disorders (e.g., staggers syndromes) in ruminants. The mode of action of these fungal mycotoxins is not understood but may be related to their known effects on neurotransmitter release. To determine whether these effects could be due to inhibition of K+ channels, the interaction of various indole diterpenes with high-conductance Ca(2+)-activated K+ (maxi-K) channels was examined. Paspalitrem A, paspalitrem C, aflatrem, penitrem A, and paspalinine inhibit binding of [125I]charybdotoxin (ChTX) to maxi-K channels in bovine aortic smooth muscle sarcolemmal membranes. In contrast, three structurally related compounds, paxilline, verruculogen, and paspalicine, enhanced toxin binding. As predicted from the binding studies, covalent incorporation of [125I]ChTX into the 31-kDa subunit of the maxi-K channel was blocked by compounds that inhibit [125I]ChTX binding and enhanced by compounds that stimulate [125I]ChTX binding. Modulation of [125I]ChTX binding was due to allosteric mechanisms. Despite their different effects on binding of [125I]ChTX to maxi-K channels, all compounds potently inhibited maxi-K channels in electrophysiological experiments. Other types of voltage-dependent or Ca(2+)-activated K+ channels examined were not affected. Chemical modifications of paxilline indicate a defined structure-activity relationship for channel inhibition. Paspalicine, a deshydroxy analog of paspalinine lacking tremorgenic activity, also potently blocked maxi-K channels. Taken together, these data suggest that indole diterpenes are the most potent nonpeptidyl inhibitors of maxi-K channels identified to date. Some of their pharmacological properties could be explained by inhibition of maxi-K channels, although tremorgenicity may be unrelated to channel block.

  11. Effect of angiotensin Ⅱ receptor blocker on glucose-induced mRNA expressions of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 in rat mesangial cells

    Institute of Scientific and Technical Information of China (English)

    DING He-lin; GUO Ying; XU Ming-tong; LI Hai-yan; FU Zu-zhi

    2007-01-01

    Background The decreased degradation of extra-cellular matrix proteins plays an important role in the onset of diabetic nephropathy. Matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1), which are members of the matrix metalloproteinase family, are associated with this process. Angiotensin il (AII) plays an important role in the development of diabetic nephropathy also. This research aimed to investigate the effect of angiotensin Ⅱ receptor blocker on glucose-induced mRNA expressions of MMP-9 and TIMP-1 in rat mesangial cells.Methods Rat mesangial cells were cultured and divided into 5 groups: normal glucose (group NG), high glucose (group HG), group NG+AII, NG+AIl+saralasin (group NG+AII+S, saralasin is the All receptor blocker) and HG+saralasin (group HG+S). After the cells were incubated for 24 hours, All concentrations in the supernatant were measured by radioimmunoassay and the expression of MMP-9 and TIMP-1 mRNA was assayed by reverse transcription-polymerase chain reaction (RT-PCR).Results All concentrations were higher in group HG ((56.90±13.54) pg/ml) and group HG+S ((51.30±5.96) pg/ml) than in group NG ((37.89±8.62) pg/ml, P<0.05), whereas there was no significant difference between group HG and group HG+S. The expression of MMP-9 mRNA and MMP-9/TIMP-1 mRNA ratio in group NG+AII (MMP-9, 0.33±0.04;MMP-9/TIMP-1, 0.40±0.06) and group HG (MMP-9, 0.36±0.02; MMP-9/TIMP-1, 0.45±0.03) were decreased more significantly than those in group NG (MMP-9, 0.72±0.02; MMP-9/TIMP-1, 1.21±0.07). These values in group NG+AII+S(MMP-9, 0.71±0.02; MMP-9/TIMP-1, 1.18±0.05) were higher than those in group NG+AII, and the values in group HG+S(MMP-9, 0.71±0.02; MMP-9/TIMP-1, 1.16±0.05) were higher than those in group HG (all were P<0.05). TIMP-1 mRNA expression was increased more significantly in group NG+AII (0.81±0.03) and group HG (0.80±0.03) than in group NG(0.59±0.02), but it was lower in group NG+AII+S (0.60±0.01) than

  12. Performance Monitoring and Response Inhibition in a Saccadic Countermanding Task in High and Low proficient bilinguals.

    Directory of Open Access Journals (Sweden)

    Niharika eSingh

    2015-01-01

    Full Text Available We compared Hindi-English bilinguals differing in their L2 fluency on a saccadic countermanding task which taps inhibitory control as well as monitoring. We particularly explored whether response inhibition and performance monitoring within the oculomotor domain are affected by language proficiency in bilinguals. There were two different oculomotor redirect tasks: Visually Guided Redirect (VGR task (Experiment1 and Memory Guided Redirect (MGR task (Experiment 2. In this task typically a target is presented to which subject must make saccade (No step trials, unless a new target appears on the other location after some delay from the first target onset (Step trials. On such trials participants are required to inhibit and cancel the saccade to the first instead program a saccade to the new target. Using trial switch reaction time (TSRT, which is the time taken to inhibit the initiated saccade to the first target, as a measure of response inhibition, and post-stop slowing as a measure of performance monitoring, we observed two important results. It was found that high proficiency bilinguals showed more post-stop slowing on the no-step trials as compared to the low proficiency bilinguals for both VGR and MGR. Secondly, high and low proficiency bilingual exhibited comparable TSRT in both VGR and MGR, showing no altering effect of language proficiency on the response inhibition in bilinguals. These results suggest that bilingualism impacts performance monitoring which is modulated by language proficiency if not the inhibitory control system. Higher fluency may lead to superior cognitive flexibility, and ability to adjust behaviour that facilitates attainment of cognitive goal. These findings are in consonance with other current studies that suggest a top-down effect of bilingualism on action control systems.

  13. High rates of chromosome missegregation suppress tumor progression but do not inhibit tumor initiation

    Science.gov (United States)

    Zasadil, Lauren M.; Britigan, Eric M. C.; Ryan, Sean D.; Kaur, Charanjeet; Guckenberger, David J.; Beebe, David J.; Moser, Amy R.; Weaver, Beth A.

    2016-01-01

    Aneuploidy, an abnormal chromosome number that deviates from a multiple of the haploid, has been recognized as a common feature of cancers for >100 yr. Previously, we showed that the rate of chromosome missegregation/chromosomal instability (CIN) determines the effect of aneuploidy on tumors; whereas low rates of CIN are weakly tumor promoting, higher rates of CIN cause cell death and tumor suppression. However, whether high CIN inhibits tumor initiation or suppresses the growth and progression of already initiated tumors remained unclear. We tested this using the ApcMin/+ mouse intestinal tumor model, in which effects on tumor initiation versus progression can be discriminated. ApcMin/+ cells exhibit low CIN, and we generated high CIN by reducing expression of the kinesin-like mitotic motor protein CENP-E. CENP-E+/−;ApcMin/+ doubly heterozygous cells had higher rates of chromosome missegregation than singly heterozygous cells, resulting in increased cell death and a substantial reduction in tumor progression compared with ApcMin/+ animals. Intestinal organoid studies confirmed that high CIN does not inhibit tumor cell initiation but does inhibit subsequent cell growth. These findings support the conclusion that increasing the rate of chromosome missegregation could serve as a successful chemotherapeutic strategy. PMID:27146113

  14. Biomass hydrolysis inhibition at high hydrogen partial pressure in solid-state anaerobic digestion.

    Science.gov (United States)

    Cazier, E A; Trably, E; Steyer, J P; Escudie, R

    2015-08-01

    In solid-state anaerobic digestion, so-called ss-AD, biogas production is inhibited at high total solids contents. Such inhibition is likely caused by a slow diffusion of dissolved reaction intermediates that locally accumulate. In this study, we investigated the effect of H2 and CO2 partial pressure on ss-AD. Partial pressure of H2 and/or CO2 was artificially fixed, from 0 to 1 557mbars for H2 and from 0 to 427mbars for CO2. High partial pressure of H2 showed a significant effect on methanogenesis, while CO2 had no impact. At high [Formula: see text] , the overall substrate degradation decreased with no accumulation of metabolites from acidogenic bacteria, indicating that the hydrolytic activity was specifically impacted. Interestingly, such inhibition did not occur when CO2 was added with H2. This result suggests that CO2 gas transfer is probably a key factor in ss-AD from biomass.

  15. Effective Inhibition of Bone Morphogenetic Protein Function by Highly Specific Llama-Derived Antibodies.

    Science.gov (United States)

    Calpe, Silvia; Wagner, Koen; El Khattabi, Mohamed; Rutten, Lucy; Zimberlin, Cheryl; Dolk, Edward; Verrips, C Theo; Medema, Jan Paul; Spits, Hergen; Krishnadath, Kausilia K

    2015-11-01

    Bone morphogenetic proteins (BMP) have important but distinct roles in tissue homeostasis and disease, including carcinogenesis and tumor progression. A large number of BMP inhibitors are available to study BMP function; however, as most of these antagonists are promiscuous, evaluating specific effects of individual BMPs is not feasible. Because the oncogenic role of the different BMPs varies for each neoplasm, highly selective BMP inhibitors are required. Here, we describe the generation of three types of llama-derived heavy chain variable domains (VHH) that selectively bind to either BMP4, to BMP2 and 4, or to BMP2, 4, 5, and 6. These generated VHHs have high affinity to their targets and are able to inhibit BMP signaling. Epitope binning and docking modeling have shed light into the basis for their BMP specificity. As opposed to the wide structural reach of natural inhibitors, these small molecules target the grooves and pockets of BMPs involved in receptor binding. In organoid experiments, specific inhibition of BMP4 does not affect the activation of normal stem cells. Furthermore, in vitro inhibition of cancer-derived BMP4 noncanonical signals results in an increase of chemosensitivity in a colorectal cancer cell line. Therefore, because of their high specificity and low off-target effects, these VHHs could represent a therapeutic alternative for BMP4(+) malignancies.

  16. Field trial on glucose-induced insulin and metabolite responses in Estonian Holstein and Estonian Red dairy cows in two herds

    Directory of Open Access Journals (Sweden)

    Kaart Tanel

    2010-01-01

    Full Text Available Abstract Background Insulin secretion and tissue sensitivity to insulin is considered to be one of the factors controlling lipid metabolism post partum. The objective of this study was to compare glucose-induced blood insulin and metabolite responses in Estonian Holstein (EH, n = 14 and Estonian Red (ER, n = 14 cows. Methods The study was carried out using the glucose tolerance test (GTT performed at 31 ± 1.9 days post partum during negative energy balance. Blood samples were obtained at -15, -5, 5, 10, 20, 30, 40, 50 and 60 min relative to infusion of 0.15 g/kg BW glucose and analysed for glucose, insulin, triglycerides (TG, non-esterified fatty acids (NEFA, cholesterol and β-hydroxybutyrate (BHB. Applying the MIXED Procedure with the SAS System the basal concentration of cholesterol, and basal concentration and concentrations at post-infusion time points for other metabolites, area under the curve (AUC for glucose and insulin, clearance rate (CR for glucose, and maximum increase from basal concentration for glucose and insulin were compared between breeds. Results There was a breed effect on blood NEFA (P P P P P P th min nadir (P th min postinfusion (P Conclusion Our results imply that glucose-induced changes in insulin concentration and metabolite responses to insulin differ between EH and ER dairy cows.

  17. Grape seed proanthocyanidins induce apoptosis and inhibit metastasis of highly metastatic breast carcinoma cells.

    Science.gov (United States)

    Mantena, Sudheer K; Baliga, Manjeshwar S; Katiyar, Santosh K

    2006-08-01

    The strategies available for the treatment of metastatic breast cancer are limited. Dietary botanicals may have a better protective effect on this disease. We therefore investigated the effects of grape seed proanthocyanidins (GSPs) on a highly metastatic mouse mammary carcinoma cell line. In vitro treatment of breast cancer cells, 4T1, MCF-7 and MDA-MB-468, with GSPs resulted in significant inhibition of cellular proliferation and viability, and induction of apoptosis in 4T1 cells in a time- and dose-dependent manner. Further analysis indicated an alteration in the ratio of Bax/Bcl-2 proteins in favor of apoptosis, and the knockdown of Bax using Bax siRNA transfection of 4T1 cells resulted in blocking of GSPs-induced apoptosis. Induction of apoptosis was associated with the release of cytochrome c, increased expression of Apaf-1 and activation of caspase 3 and poly (ADP-ribose) polymerase. Treatment with the pan-caspase inhibitor (Z-VAD-FMK) resulted in partial but significant inhibition of apoptosis in 4T1 cells suggesting the involvement of both caspase activation-dependent and activation-independent pathways in the apoptosis of 4T1 cells induced by GSPs. The effects of dietary GSPs were then examined using an in vivo model in which 4T1 cells were implanted subcutaneously in Balb/c mice. Dietary GSPs (0.2 and 0.5%, w/w) significantly inhibited the growth of the implanted 4T1 tumor cells and increased the ratio of Bax:Bcl-2 proteins, cytochrome c release, induction of Apaf-1 and activation of caspase 3 in the tumor microenvironment. Notably, the metastasis of tumor cells to the lungs was inhibited significantly and the survival of the mice enhanced. These data suggest that GSPs possess chemotherapeutic efficacy against breast cancer including inhibition of metastasis.

  18. Growth Inhibition Occurs Independently of Cell Mortality in Tomato (Solanum lycopersicum) Exposed to High Cadmium Concentrations

    Institute of Scientific and Technical Information of China (English)

    Christine Delpérée; Stanley Lutts

    2008-01-01

    In order to analyze the adaptation potential of tomato shoots to a sudden increase in Cd concentration, tomato plants (Solanum lycopersicum L. var. Ailsa Craig) were exposed under controlled environmental conditions to a high dose of this heavy metal (250 μM CdCl2>) in nutrient solution for 7 and 14 d. Both root and shoot growth was completely inhibited but all plants remained alive until the end of the treatment. Cell viability remained unaffected but the activity of the mitochondrial alternative pathway was stimulated by Cd stress at the expense of the cytochrome pathway. Cadmium concentration was higher in roots than in shoots and a decrease In the rate of net Cd translocation was noticed during the second week of stress. Cadmium decreased both leaf conductance (g1>) and chlorophyll concentration. However, the effect on net CO2 assimilation remained limited and soluble sugars accumulated in leaves. Photochemical efficiency of PSll (FvlFm) was not affected despite a decrease in the number of reaction centers and an inhibition of electron transfer to acceptors of PSII. It is concluded that tomato shoot may sustain short term exposure to high doses of cadmium despite growth inhibition. This property implies several physiological strategies linked to both avoidance and tolerance mechanisms.

  19. Magnetic Separation-Assistant Fluorescence Resonance Energy Transfer Inhibition for Highly Sensitive Probing of Nucleolin.

    Science.gov (United States)

    Li, Yan-Ran; Liu, Qian; Hong, Zhangyong; Wang, He-Fang

    2015-12-15

    For the widely used "off-on" fluorescence (or phosphorescence) resonance energy transfer (FRET or PRET) system, the separation of donors and acceptors species was vital for enhancing the sensitivity. To date, separation of free donors from FRET/PRET inhibition systems was somewhat not convenient, whereas separation of the target-induced far-between acceptors has hardly been reported yet. We presented here a novel magnetic separation-assistant fluorescence resonance energy transfer (MS-FRET) inhibition strategy for highly sensitive detection of nucleolin using Cy5.5-AS1411 as the donor and Fe3O4-polypyrrole core-shell (Fe3O4@PPY) nanoparticles as the NIR quenching acceptor. Due to hydrophobic interaction and π-π stacking of AS1411 and PPY, Cy5.5-AS1411 was bound onto the surface of Fe3O4@PPY, resulting in 90% of fluorescence quenching of Cy5.5-AS1411. Owing to the much stronger specific interaction of AS1411 and nucleolin, the presence of nucleolin could take Cy5.5-AS1411 apart from Fe3O4@PPY and restore the fluorescence of Cy5.5-AS1411. The superparamagnetism of Fe3O4@PPY enabled all separations and fluorescence measurements complete in the same quartz cell, and thus allowed the convenient but accurate comparison of the sensitivity and fluorescence recovery in the cases of separation or nonseparation. Compared to nonseparation FRET inhibition, the separation of free Cy5.5-AS1411 from Cy5.5-AS1411-Fe3O4@PPY solution (the first magnetic separation, MS-1) had as high as 25-fold enhancement of the sensitivity, whereas further separation of the nucleolin-inducing far-between Fe3O4@PPY from the FRET inhibition solution (the second magnetic separation, MS-2) could further enhance the sensitivity to 35-fold. Finally, the MS-FRET inhibition assay displayed the linear range of 0.625-27.5 μg L(-1) (8.1-359 pM) and detection limit of 0.04 μg L(-1) (0.05 pM) of nucleolin. The fluorescence intensity recovery (the percentage ratio of the final restoring fluorescence intensity

  20. Decreased latent inhibition is associated with increased creative achievement in high-functioning individuals.

    Science.gov (United States)

    Carson, Shelley H; Peterson, Jordan B; Higgins, Daniel M

    2003-09-01

    Reductions in latent inhibition (LI), the capacity to screen from conscious awareness stimuli previously experienced as irrelevant, have been generally associated with the tendency towards psychosis. However, "failure" to screen out previously irrelevant stimuli might also hypothetically contribute to original thinking, particularly in combination with high IQ. Meta-analysis of two studies, conducted on youthful high-IQ samples. demonstrated that high lifetime creative achievers had significantly lower LI scores than low creative achievers (r(effect size) = .31, p = .0003, one-tailed). Eminent creative achievers (participants under 21 years who reported unusually high scores in a single domain of creative achievement) were 7 times more likely to have low rather than high LI scores, chi2 (1, N = 25) = 10.69, phi = .47. p = .003.

  1. Low-Temperature CO Oxidation over a Ternary Oxide Catalyst with High Resistance to Hydrocarbon Inhibition.

    Science.gov (United States)

    Binder, Andrew J; Toops, Todd J; Unocic, Raymond R; Parks, James E; Dai, Sheng

    2015-11-02

    Platinum group metal (PGM) catalysts are the current standard for control of pollutants in automotive exhaust streams. Aside from their high cost, PGM catalysts struggle with CO oxidation at low temperatures (oxide catalyst composed of copper oxide, cobalt oxide, and ceria (dubbed CCC) that outperforms synthesized and commercial PGM catalysts for CO oxidation in simulated exhaust streams while showing no signs of inhibition by propene. Diffuse reflectance IR (DRIFTS) and light-off data both indicate low interaction between propene and the CO oxidation active site on this catalyst, and a separation of adsorption sites is proposed as the cause of this inhibition resistance. This catalyst shows great potential as a low-cost component for low temperature exhaust streams that are expected to be a characteristic of future automotive systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. High pressure and anesthesia: pressure stimulates or inhibits bacterial bioluminescence depending upon temperature.

    Science.gov (United States)

    Nosaka, S; Kamaya, H; Ueda, I

    1988-10-01

    Although high pressure is often viewed as a nonspecific stimulus counteracting anesthesia, pressure can either excite or inhibit biological activity depending on the temperature at application. Temperature and pressure are two independent variables that determine equilibrium quantity, e.g., the state of organisms in terms of activity and anesthesia depth. We used the light intensity of luminous bacteria (Vibrio fischeri) as an activity parameter, and studied the effects of pressure and anesthetics on the bacteria's light intensity at various temperatures. The light intensity was greatest at about 30 degrees C at ambient pressure. When the system was pressurized up to 204 atm, the temperature for maximum light intensity was shifted to higher temperatures. Above the optimal temperature for the maximal light intensity, high pressure increased the light intensity. Below the optimal temperature, pressure decreased light intensity. Pressure only shifts the reaction equilibrium to the lower volume state (Le Chatelier's principle). When the volume of the excited state is larger than the resting state, high pressure inhibits excitation, and vice versa. Halothane 0.008 atm and isoflurane 0.021 atm inhibited the light intensity both above and below the optimal temperature. When pressurized, the light intensity increased in the high temperature range but decreased in the low temperature range, as in the control. Thus, high pressure seemingly potentiated the anesthetic action at low temperatures. When the ratio of the light intensity in bacteria exposed to anesthesia and those not exposed to anesthesia was plotted against the pressure, however, the value approached unity in proportion to the pressure increase.(ABSTRACT TRUNCATED AT 250 WORDS)

  3. Pistachio intake increases high density lipoprotein levels and inhibits low-density lipoprotein oxidation in rats.

    Science.gov (United States)

    Aksoy, Nur; Aksoy, Mehmet; Bagci, Cahit; Gergerlioglu, H Serdar; Celik, Hakim; Herken, Emine; Yaman, Abdullah; Tarakcioglu, Mehmet; Soydinc, Serdar; Sari, Ibrahim; Davutoglu, Vedat

    2007-05-01

    There is increasing evidence that nuts have protective effects against coronary artery disease by improving lipid profile and inhibiting lipid oxidation. However, data about pistachio nuts are limited, and to our knowledge, there is no study investigating the effects of pistachio intake on lipid oxidation and serum antioxidant levels. This study, therefore, sought to determine the effects of pistachio intake on serum lipids and determine whether consumption of pistachio would alter serum antioxidant levels. Rats were randomly divided into three groups (n=12 for each): control group fed basic diet for 10 weeks and treated groups fed basic diet plus pistachio which constituted 20% and 40% of daily caloric intake, respectively. Consumption of pistachio as 20% of daily caloric intake increased high-density lipoprotein (HDL) levels and decreased total cholesterol (TC)/HDL ratio, compared with those not taking pistachio. However, TC, low-density lipoprotein (LDL) cholesterol and triglyceride levels were unaffected by pistachio consumption. Consumption of pistachio as 20% of daily caloric intake increased serum paraoxonase activity by 35% and arylesterase activity by 60%, which are known to inhibit LDL cholesterol oxidation, compared with the control group. However, increased antioxidant activity was blunted when pistachio intake was increased to 40% of daily caloric intake. In conclusion, the present results show that consumption of pistachio as 20% of daily caloric intake leads to significant improvement in HDL and TC/HDL ratio and inhibits LDL cholesterol oxidation. These results suggest that pistachio may be beneficial for both prevention and treatment of coronary artery disease.

  4. A high-throughput assay for quantification of starch hydrolase inhibition based on turbidity measurement.

    Science.gov (United States)

    Liu, Tingting; Song, Lixia; Wang, Hongyu; Huang, Dejian

    2011-09-28

    A high-throughput method for rapid determination of starch hydrolase inhibition was developed using a 96-well microplate UV-vis reader to monitor the turbidity decrease over time. The area under the curve of turbidity measured over time was used to quantify the inhibitory effect of polyphenolic compounds on porcine pancreatic amylase, rat intestine α-glucosidase, and fungal amyloglucosidase. Acarbose equivalence (AE) was introduced for the first time and defined as IC50 of acarbose divided by the IC50 of the sample measured under the same 96-well plate. This way, the run-to-run variations are canceled out. Among the plant extracts tested, grape seed extracts (1,440 μmolAE/g) and cinnamon bark extracts (1600 μmolAE/g) are the most active in inhibiting rat intestine α-glucosidase. For porcine α-amylase inhibition, grape seed extracts (5710 μmol AE/g) are close to four times more active (equal weight basis) than acarbose (1550 μmolAE/g).

  5. 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.

  6. 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.

  7. 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.

  8. High-oxygen and high-carbon dioxide containing atmospheres inhibit growth of food associated moulds

    NARCIS (Netherlands)

    Hoogerwerf, S.W.; Kets, E.P.W.; Dijksterhuis, J.

    2002-01-01

    Aims: The objective of this study was to determine the relationship between the growth of three foodborne fungi and high-oxygen modified atmosphere. Methods and Results: Petri dishes were incubated in a series of connected flasks, which were placed in a climatized room and flushed continuously with

  9. High-oxygen and high-carbon dioxide containing atmospheres inhibit growth of food associated moulds

    NARCIS (Netherlands)

    Hoogerwerf, S W; Kets, E P W; Dijksterhuis, J

    2002-01-01

    AIMS: The objective of this study was to determine the relationship between the growth of three foodborne fungi and high-oxygen modified atmosphere. METHODS AND RESULTS: Petri dishes were incubated in a series of connected flasks, which were placed in a climatized room and flushed continuously with

  10. CNTF inhibits high voltage activated Ca2+ currents in fetal mouse cortical neurones

    DEFF Research Database (Denmark)

    Holm, Ninna R; Christophersen, Palle; Hounsgaard, Jørn;

    2002-01-01

    Neurotrophic factors yield neuroprotection by mechanisms that may be related to their effects as inhibitors of apoptosis as well as their effects on ion channels. The effect of ciliary neurotrophic factor (CNTF) on high-threshold voltage-activated Ca channels in cultured fetal mouse brain cortical...... neurones was investigated. Addition of CNTF into serum-free growth medium resulted in delayed reduction of the Ca2+ currents. The currents decreased to 50% after 4 h and stabilized at this level during incubation with CNTF for 48 h. Following removal of CNTF the inhibition was completely reversed after 18...

  11. Inhibition of photosynthesis and energy dissipation induced by water and high light stresses in rice.

    Science.gov (United States)

    Zhou, Yanhong; Lam, Hon Ming; Zhang, Jianhua

    2007-01-01

    Photoprotection mechanisms of rice plants were studied when its seedlings were subjected to the combined stress of water and high light. The imposition of water stress, induced by PEG 6000 which was applied to roots, resulted in substantial inhibition of stomatal conductance and net photosynthesis under all irradiance treatments. Under high light stress, the rapid decline of photosynthesis with the development of water stress was accompanied by decreases in the maximum velocity of RuBP carboxylation by Rubisco (V(cmax)), the capacity for ribulose-1,5-bisphosphate regeneration (J(max)), Rubisco and stromal FBPase activities, and the quantum efficiency of photosystem II, in the absence of any stomatal limitation of CO(2) supply. Water stress significantly reduced the energy flux via linear electron transport (J(PSII)), but increased light-dependent and DeltapH- and xanthophyll-mediated thermal dissipation (J(NPQ)). It is concluded that the drought-induced inhibition of photosynthesis under different irradiances in the rice was due to both diffusive and metabolic limitations. Metabolic limitation of photosynthesis may be related to the adverse effects of some metabolic processes and the oxidative damage to the chloroplast. Meanwhile, an enhanced thermal dissipation is an important process to minimize the adverse effects of drought and high irradiance when CO(2) assimilation is suppressed.

  12. Short-interval intracortical inhibition is modulated by high-frequency peripheral mixed nerve stimulation.

    Science.gov (United States)

    Murakami, Takenobu; Sakuma, Kenji; Nomura, Takashi; Nakashima, Kenji

    2007-06-01

    Cortical excitability can be modulated by manipulation of afferent input. We investigated the influence of peripheral mixed nerve stimulation on the excitability of the motor cortex. Motor evoked potentials (MEPs), short-interval intracortical inhibition (SICI) and intracortical facilitation (ICF) in the right abductor pollicis brevis (APB), extensor carpi radialis (ECR) and first dorsal interosseous (FDI) muscles were evaluated using paired-pulse transcranial magnetic stimulation (TMS) before and after high-frequency peripheral mixed nerve stimulation (150 Hz, 30 min) over the right median nerve at the wrist. The MEP amplitude and SICI of the APB muscle decreased transiently 0-10 min after the intervention, whereas the ICF did not change. High-frequency peripheral mixed nerve stimulation reduced the excitability of the motor cortex. The decrement in the SICI, which reflects the function of GABA(A)ergic inhibitory interneurons, might compensate for the reduced motor cortical excitability after high-frequency peripheral mixed nerve stimulation.

  13. Inhibition and deactivation effects in catalytic wet oxidation of high-strength alcohol-distillery liquors

    Energy Technology Data Exchange (ETDEWEB)

    Belkacemi, K.; Larachi, F.; Hamoudi, S.; Turcotte, G.; Sayari, A. [Laval Univ., Sainte-Foy, Quebec (Canada)

    1999-06-01

    The removal efficiency of total organic carbon (TOC) from raw high-strength alcohol-distillery waste liquors was evaluated using three different treatments: thermolysis (T), noncatalytic wet oxidation (WO), and solid-catalyzed wet oxidation (CWO). The distillery liquors (TOC = 22,500 mg/l, sugars = 18,000 mg/l, and proteins = 13,500 mg/l) were produced by alcoholic fermentation of enzymatic hydrolyzates from steam-exploded timothy grass. TOC-abatement studies were conducted batchwise in a stirred autoclave to evaluate the influence of the catalyst (7:3, MnO{sub 2}/CeO{sub 2} mixed oxide), oxygen partial pressure (0.5--2.5 MPa), and temperature (453--523 K) on T, WO, and CWO processes. Although CWO outperformed T and WO, TOC conversions did not exceed {approximately}60% at the highest temperature used. Experiments provided prima facie evidence for a gradual fouling of the catalyst and a developing inhibition in the liquors which impaired deep TOC removals. Occurrence of catalyst deactivation by carbonaceous deposits was proven experimentally through quantitative and qualitative experiments such as elemental analysis and X-ray photoelectron spectroscopy. Inhibition toward further degradation of the liquors was ascribed to the occurrence of highly stable antioxidant intermediates via the Maillard reactions between dissolved sugars and proteins. A lumping kinetic model involving both reaction inhibition by dissolved intermediates and catalyst deactivation by carbonaceous deposits was proposed to account for the distribution of carbon in the liquid, solid, and the vapor phases.

  14. A statin-loaded reconstituted high-density lipoprotein nanoparticle inhibits atherosclerotic plaque inflammation

    Science.gov (United States)

    Duivenvoorden, Raphaël; Tang, Jun; Cormode, David P.; Mieszawska, Aneta J.; Izquierdo-Garcia, David; Ozcan, Canturk; Otten, Maarten J.; Zaidi, Neeha; Lobatto, Mark E.; van Rijs, Sarian M.; Priem, Bram; Kuan, Emma L.; Martel, Catherine; Hewing, Bernd; Sager, Hendrik; Nahrendorf, Matthias; Randolph, Gwendalyn J.; Stroes, Erik S. G.; Fuster, Valentin; Fisher, Edward A.; Fayad, Zahi A.; Mulder, Willem J. M.

    2014-01-01

    Inflammation is a key feature of atherosclerosis and a target for therapy. Statins have potent anti-inflammatory properties but these cannot be fully exploited with oral statin therapy due to low systemic bioavailability. Here we present an injectable reconstituted high-density lipoprotein (rHDL) nanoparticle carrier vehicle that delivers statins to atherosclerotic plaques. We demonstrate the anti-inflammatory effect of statin-rHDL in vitro and show that this effect is mediated through the inhibition of the mevalonate pathway. We also apply statin-rHDL nanoparticles in vivo in an apolipoprotein E-knockout mouse model of atherosclerosis and show that they accumulate in atherosclerotic lesions in which they directly affect plaque macrophages. Finally, we demonstrate that a 3-month low-dose statin-rHDL treatment regimen inhibits plaque inflammation progression, while a 1-week high-dose regimen markedly decreases inflammation in advanced atherosclerotic plaques. Statin-rHDL represents a novel potent atherosclerosis nanotherapy that directly affects plaque inflammation.

  15. Dietary intake of high-dose biotin inhibits spermatogenesis in young rats.

    Science.gov (United States)

    Sawamura, Hiromi; Ikeda, Chieko; Shimada, Ryoko; Yoshii, Yui; Watanabe, Toshiaki

    2015-02-01

    To characterize a new function of the water-soluble vitamin, biotin, in reproduction and early growth in mammals, the effects of high dietary doses of biotin on early spermatogenesis were biochemically and histologically investigated in male rats. Weaned rats were fed a CE-2 (control) diet containing 0.00004% biotin, or a control diet supplemented with 0.01%, 0.1%, or 1.0% biotin. Pair-fed rats were fed a control diet that was equal in calories to the amount ingested by the 1.0% biotin group, because food intake was decreased in the 1.0% biotin group. Food intake and body weight gain were lower in the 1.0% biotin group than in the control group. The kidney, brain and testis weights were significantly lower in the 1.0% biotin group than in the pair-fed group after 6 weeks of feeding. The accumulation of biotin in the liver and testis increased in a dose-dependent manner. In the 1.0% biotin group, the number of mature sperm was markedly lower, that of sperm with morphologically abnormal heads, mainly consisting of round heads, had increased. In addition, the development of seminiferous tubules was inhibited, and few spermatogonia and no spermatocytes were histologically observed. These results demonstrated that the long-term intake of high-dose biotin inhibited spermatogenesis in young male rats.

  16. Inhibition of Ce3+ on Stress Corrosion Crack of High Strength Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    LI Wen-ting

    2017-05-01

    Full Text Available The stress corrosion cracking (SCC susceptibility of 7A04 high strength aluminum alloy in 3.5% (mass fraction NaCl solution and the Ce3+ inhibition of SCC were investigated by slow stress rate test(SSRT, using constant current polarization, electrochemical noise (ECN and electrochemical impedance spectroscopy (EIS techniques. The inhibition mechanism of Ce3+ ions on the initiation and propagation of cracking was also analyzed. The results indicate that both anodic and cathodic galvanostatic polarizations can accelerate the SCC of 7A04, the former increases anodic dissolution but the latter accelerates hydrogen embrittlement of crack tip. SCC susceptibility of 7A04 can be reduced effectively by the addition of cerium ions, the fracture time is delayed and slowed down, but only during the initiation other than the propagation stage of cracking. Ce3+ ions can restrain the initiation of metastable pitting on the surface of 7A04 specimen, which therefore increase the induction time of the cracking since that the micro pits are usually the source of cracking.However, once the crack begins to propagate or the specimen is notched, the addition of cerium ions can rarely inhibit the cracking process. This is possibly attributed to that the radius of Ce3+ ion is too large to diffuse into the crack tip or it is hard to form protective CeO2 layer, Ce3+ ion therefore fails to rehabilitate the active alloy at the crack tip and further reduce the SCC developing rate of 7A04. SEM also indicates that the crack initiation of smooth 7A04 specimens is mainly induced by metastable or stable pits.

  17. Development of a thyroperoxidase inhibition assay for high-throughput screening.

    Science.gov (United States)

    Paul, Katie B; Hedge, Joan M; Rotroff, Daniel M; Hornung, Michael W; Crofton, Kevin M; Simmons, Steven O

    2014-03-17

    High-throughput screening (HTPS) assays to detect inhibitors of thyroperoxidase (TPO), the enzymatic catalyst for thyroid hormone (TH) synthesis, are not currently available. Herein, we describe the development of a HTPS TPO inhibition assay. Rat thyroid microsomes and a fluorescent peroxidase substrate, Amplex UltraRed (AUR), were employed in an end-point assay for comparison to the existing kinetic guaiacol (GUA) oxidation assay. Following optimization of assay metrics, including Z', dynamic range, and activity, using methimazole (MMI), the assay was tested with a 21-chemical training set. The potency of MMI-induced TPO inhibition was greater with AUR compared to GUA. The dynamic range and Z' score with MMI were as follows: 127-fold and 0.62 for the GUA assay, 18-fold and 0.86 for the 96-well AUR assay, and 11.5-fold and 0.93 for the 384-well AUR assay. The 384-well AUR assay drastically reduced animal use, requiring one-tenth of the rat thyroid microsomal protein needed for the GUA 96-well format assay. Fourteen chemicals inhibited TPO, with a relative potency ranking of MMI > ethylene thiourea > 6-propylthiouracil > 2,2',4,4'-tetrahydroxy-benzophenone > 2-mercaptobenzothiazole > 3-amino-1,2,4-triazole > genistein > 4-propoxyphenol > sulfamethazine > daidzein > 4-nonylphenol > triclosan > iopanoic acid > resorcinol. These data demonstrate the capacity of this assay to detect diverse TPO inhibitors. Seven chemicals acted as negatives: 2-hydroxy-4-methoxybenzophenone, dibutylphthalate, diethylhexylphthalate, diethylphthalate, 3,5-dimethylpyrazole-1-methanol, methyl 2-methyl-benzoate, and sodium perchlorate. This assay could be used to screen large numbers of chemicals as an integral component of a tiered TH-disruptor screening approach.

  18. Inhibition effects of high calcium concentration on anaerobic biological treatment of MSW leachate.

    Science.gov (United States)

    Xia, Yi; He, Pin-Jing; Pu, Hong-Xia; Lü, Fan; Shao, Li-Ming; Zhang, Hua

    2016-04-01

    With the increasing use of municipal solid waste incineration (MSWI) and more stringent limits on landfilling of organic waste, more MSWI bottom ash is being landfilled, and the proportion of inorganic wastes in landfills is increasing, causing the increased Ca concentrations in landfill leachate. In this research, the inhibition effect of Ca concentration on the anaerobic treatment of landfill leachate was studied using a biochemical methane potential experiment. Slight inhibition of methane production occurred when the addition of Ca concentration was less than 2000 mg/L. When the addition of Ca concentration was between 6000 and 8000 mg/L, methane production was significantly reduced (to 29.4-34.8 % of that produced by the BLK reactor), and the lag phase was increased from 8.55 to 16.32 d. Moreover, when the dosage of Ca concentration increased from zero to 8000 mg/L, reductions in solution Ca concentration increased from 929 to 2611 mg/L, and the proportion of Ca in the residual sludge increased from 22.58 to 46.87 %. Based on the results, when the dosage of Ca concentration was less than 4000 mg/L, the formation of Ca precipitates on the surface of sludge appeared to prevent mass transfer and was the dominant reason for the reduction in methane production and sludge biomass. At higher Ca concentrations (6000-8000 mg/L), the severe inhibition of methane production appeared to be caused by the toxic effect of highly concentrated Ca on sludge as well as mass transfer blockage.

  19. Magnetic Flashover Inhibition Testing of High Power Vacuum-Insulator Interfaces

    Science.gov (United States)

    Benwell, Andrew; Kovaleski, Scott; Gahl, John

    2004-11-01

    University of Missouri Terawatt Test Stand, Department of Electrical and Computer Engineering, University of Missouri Â- Columbia, Columbia, MO. Flashover occurring at vacuum-insulator interfaces is a common problem in the design of high power pulsed power machines. Avalanche breakdown might be prevented on the insulator surface by taking advantage of the E × B force to bend the path of electrons away from the insulator. Magnetic flashover inhibition (MFI) has been demonstrated [1]; however particular breakdown conditions such as the ratio of E/B are not well known. An inductive load to test the conditions under which MFI occurs is being designed for the MU Terrawatt Test Stand (MUTTS). The test stand can provide a 150 ns pulse at 2.7MV and 400kA peak and can accommodate an adjustable design load. Details of the load design will be presented as well as theoretical analysis of the experimental circuit and of the physics of magnetic flashover insulation. [1] J.P. VanDevender, D.H. McDaniel, E.L. Neau, R.E. Mattis, K.D. Bergeron, "Magnetic Inhibition of Insulator Flashover", Journal of Applied Physics 53(6), June 1982

  20. Therapeutic Blockade of Immune Complex-Mediated Glomerulonephritis by Highly Selective Inhibition of Bruton's Tyrosine Kinase.

    Science.gov (United States)

    Chalmers, Samantha A; Doerner, Jessica; Bosanac, Todd; Khalil, Sara; Smith, Dustin; Harcken, Christian; Dimock, Janice; Der, Evan; Herlitz, Leal; Webb, Deborah; Seccareccia, Elise; Feng, Di; Fine, Jay S; Ramanujam, Meera; Klein, Elliott; Putterman, Chaim

    2016-05-19

    Lupus nephritis (LN) is a potentially dangerous end organ pathology that affects upwards of 60% of lupus patients. Bruton's tyrosine kinase (BTK) is important for B cell development, Fc receptor signaling, and macrophage polarization. In this study, we investigated the effects of a novel, highly selective and potent BTK inhibitor, BI-BTK-1, in an inducible model of LN in which mice receive nephrotoxic serum (NTS) containing anti-glomerular antibodies. Mice were treated once daily with vehicle alone or BI-BTK-1, either prophylactically or therapeutically. When compared with control treated mice, NTS-challenged mice treated prophylactically with BI-BTK-1 exhibited significantly attenuated kidney disease, which was dose dependent. BI-BTK-1 treatment resulted in decreased infiltrating IBA-1+ cells, as well as C3 deposition within the kidney. RT-PCR on whole kidney RNA and serum profiling indicated that BTK inhibition significantly decreased levels of LN-relevant inflammatory cytokines and chemokines. Renal RNA expression profiling by RNA-seq revealed that BI-BTK-1 dramatically modulated pathways related to inflammation and glomerular injury. Importantly, when administered therapeutically, BI-BTK-1 reversed established proteinuria and improved renal histopathology. Our results highlight the important role for BTK in the pathogenesis of immune complex-mediated nephritis, and BTK inhibition as a promising therapeutic target for LN.

  1. Antibodies toward high-density lipoprotein components inhibit paraoxonase activity in patients with systemic lupus erythematosus.

    Science.gov (United States)

    Batuca, J R; Ames, P R J; Isenberg, D A; Alves, J Delgado

    2007-06-01

    Patients with systemic lupus erythematosus (SLE) have an increased incidence of vascular disease, and oxidative stress is recognized as an important feature in this condition, despite the underlying mechanisms not being fully understood. In these patients, an interaction between lipoproteins and the immune system has been suggested, but most studies have only looked at antibodies against oxidized low-density lipoproteins. This study was undertaken to determine the presence of antibodies directed against high-density lipoproteins (HDL) and to identify a possible association between these antibodies and paraoxonase (PON), an antioxidant enzyme present in HDL. Plasma from 55 patients with SLE was collected and IgG aHDL and antiapolipoprotein A-I (aApo A-I) antibodies were assessed by enzyme-linked immunosorbent assay. Standardization of the method was performed in a control population of 150 healthy subjects. Plasma levels above 5 standard deviations of the mean of the control population were considered positive. PON activity was assessed by quantification of p-nitrophenol formation (micromol/mL/min). Patients with SLE had higher titers of aHDL (P aHDL and aApo A-I antibodies (r = 0.61; P aHDL and aApo A-I antibodies in patients with SLE. These antibodies were associated with reduced PON activity in plasma, and the in vitro inhibition assay confirmed a direct inhibition of the enzyme activity.

  2. Inhibition of rho kinase attenuates high flow induced pulmonary hypertension in rats

    Institute of Scientific and Technical Information of China (English)

    LI Fu-hai; XIA Wei; LI Ai-wu; ZHAO Cui-fen; SUN Ruo-peng

    2007-01-01

    Background The RhoA/Rho kinase pathway may participate in the pathogenesis of hypoxia and monocrotaline induced pulmonary hypertension. This study tested whether RhoA/Rho kinase pathway is involved in the pathogenesis of high flow induced pulmonary hypertension in rats.Methods Male Wistar rats (4 weeks) were randomly divided into 4 shunt groups, 4 treated groups and 4 control groups.Shunt and treated groups underwent left common carotid artery/external jugular vein shunt operation. Control groups underwent sham operation. Treated groups received fasudil treatment and the others received same dose of saline. At weeks 1, 2, 4 and 8 of the study, right ventricular systolic pressure was measured and blood gases were analysed to calculate Qp/Qs. The weight ratio of right ventricle to left ventricle plus septum and the mean percentage of medial wall thickness in moderate sized pulmonary arteries were obtained. RhoA activity in pulmonary arteries was detected using Rho activity assay reagent. Rho kinase activity was quantified by the extent of MYPT1 phosphorylation with Western blot.Proliferating cells were evaluated using proliferating cell nuclear antigen immunohistological staining.Results Carotid artery/jugular vein shunt resulted in high pulmonary blood flow, both an acute and a chronic elevation of right ventricular systolic pressure, significant medial wall thickening characterized by smooth muscle cells proliferation,right ventricular hypertrophy and increased activation of RhoA and Rho kinase. Fasudil treatment lowered pulmonary artery systolic pressure, suppressed pulmonary artery smooth muscle cells proliferation, attenuated pulmonary artery medial wall thickening and inhibited right ventricular hypertrophy together with significant suppression of Rho kinase activity but not Rho activity.Conclusions Activated RhoA/Rho kinase pathway is associated with both the acute pulmonary vasoconstriction and the chronic pulmonary artery remodelling of high flow induced

  3. Changes in glucose-induced plasma active glucagon-like peptide-1 levels by co-administration of sodium–glucose cotransporter inhibitors with dipeptidyl peptidase-4 inhibitors in rodents

    Directory of Open Access Journals (Sweden)

    Takahiro Oguma

    2016-12-01

    Full Text Available We investigated whether structurally different sodium–glucose cotransporter (SGLT 2 inhibitors, when co-administered with dipeptidyl peptidase-4 (DPP4 inhibitors, could enhance glucagon-like peptide-1 (GLP-1 secretion during oral glucose tolerance tests (OGTTs in rodents. Three different SGLT inhibitors—1-(β-d-Glucopyranosyl-4-chloro-3-[5-(6-fluoro-2-pyridyl-2-thienylmethyl]benzene (GTB, TA-1887, and canagliflozin—were examined to assess the effect of chemical structure. Oral treatment with GTB plus a DPP4 inhibitor enhanced glucose-induced plasma active GLP-1 (aGLP-1 elevation and suppressed glucose excursions in both normal and diabetic rodents. In DPP4-deficient rats, GTB enhanced glucose-induced aGLP-1 elevation without affecting the basal level, whereas metformin, previously reported to enhance GLP-1 secretion, increased both the basal level and glucose-induced elevation. Oral treatment with canagliflozin and TA-1887 also enhanced glucose-induced aGLP-1 elevation when co-administered with either teneligliptin or sitagliptin. These data suggest that structurally different SGLT2 inhibitors enhance plasma aGLP-1 elevation and suppress glucose excursions during OGTT when co-administered with DPP4 inhibitors, regardless of the difference in chemical structure. Combination treatment with DPP4 inhibitors and SGLT2 inhibitors having moderate SGLT1 inhibitory activity may be a promising therapeutic option for improving glycemic control in patients with type 2 diabetes mellitus.

  4. Twelve weeks treatment with the DPP-4 inhibitor, sitagliptin, prevents degradation of peptide YY and improves glucose and non-glucose induced insulin secretion in patients with type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Aaboe, K; Knop, F K; Vilsbøll, T

    2010-01-01

    To examine the effects of 12 weeks of treatment with the DPP-4 inhibitor, sitagliptin, on gastrointestinal hormone responses to a standardized mixed meal and beta cell secretory capacity, measured as glucose and non-glucose induced insulin secretion during a hyperglycaemic clamp, in patients with...

  5. Sub-high Temperature and High Light Intensity Induced Irreversible Inhibition on Photosynthesis System of Tomato Plant (Solanum lycopersicum L.)

    Science.gov (United States)

    Lu, Tao; Meng, Zhaojuan; Zhang, Guoxian; Qi, Mingfang; Sun, Zhouping; Liu, Yufeng; Li, Tianlai

    2017-01-01

    High temperature and high light intensity is a common environment posing a great risk to organisms. This study aimed to elucidate the effects of sub-high temperature and high light intensity stress (HH, 35°C, 1000 μmol⋅m-2⋅s-1) and recovery on the photosynthetic mechanism, photoinhibiton of photosystem II (PSII) and photosystem I (PSI), and reactive oxygen (ROS) metabolism of tomato seedlings. The results showed that with prolonged stress time, net photosynthetic rate (Pn), Rubisco activity, maximal photochemistry efficiency (Fv/Fm), efficient quantum yield and electron transport of PSII [Y(II) and ETR(II)] and PSI [Y(I) and ETR(I)] decreased significantly whereas yield of non-regulated and regulated energy dissipation of PSII [Y(NO) and Y(NPQ)] increased sharply. The donor side limitation of PSI [Y(ND)] increased but the acceptor side limitation of PSI [Y(NA)] decreased. Content of malondialdehyde (MDA) and hydrogen peroxide (H2O2) were increased while activity of superoxide dismutase (SOD) and peroxidase (POD) were significantly inhibited compared with control. HH exposure affected photosynthetic carbon assimilation, multiple sites in PSII and PSI, ROS accumulation and elimination of Solanum lycopersicum L.

  6. Inhibition of highly pathogenic PRRSV replication in MARC-145 cells by artificial microRNAs

    Directory of Open Access Journals (Sweden)

    Wang Liangliang

    2011-11-01

    Full Text Available Abstract Background Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS has caused large economic losses in swine industry in recent years. However, current antiviral strategy could not effectively prevent and control this disease. In this research, five artificial microRNAs (amiRNAs respectively targeted towards ORF5 (amirGP5-243, -370 and ORF6 (amirM-82, -217,-263 were designed and incorporated into a miRNA-based vector that mimics the backbone of murine miR-155 and permits high expression of amiRNAs in a GFP fused form mediated by RNA Pol II promoter CMV. Results It was found that amirGP5-370 could effectively inhibit H-PRRSV replication. The amirM-263-M-263, which was a dual pre-amiRNA expression cassette where two amirM-263s were chained, showed stronger virus inhibitory effects than single amirM-263. H-PRRSV replication was inhibited up to 120 hours in the MARC-145 cells which were stably transduced by recombinant lentiviruses (Lenti-amirGP5-370, -amirM-263-M-263. Additionally, efficacious dose of amirGP5-370 and amirM-263 expression did not trigger the innate interferon response. Conclusions Our study is the first attempt to suppress H-PRRSV replication in MARC-145 cells through vector-based and lentiviral mediated amiRNAs targeting GP5 or M proteins coding sequences of PRRSV, which indicated that artificial microRNAs and recombinant lentiviruses might be applied to be a new potent anti-PRRSV strategy.

  7. High cholesterol diet increases osteoporosis risk via inhibiting bone formation in rats

    Institute of Scientific and Technical Information of China (English)

    Li YOU; Zheng-yan SHENG; Chuan-ling TANG; Lin CHEN; Ling PAN; Jin-yu CHEN

    2011-01-01

    To investigate the effects of high cholesterol diet on the development of osteoporosis and the underlying mechanisms in rats.Methods:Female Sprague-Dawley rats were randomly separated into 3 groups:(1) the high cholesterol fed rats were fed a high cholesterol diet containing 77% normal diet food,3% cholesterol and 20% lard for 3 months; (2) ovariectomised (OVX) rats were bilaterally ovariectomised and fed a standard diet; and (3) the control rats were fed the standard diet.Bone mineral density (BMD) of the rats was measured using dual-energy X-ray absorptiometry.Serum levels of oestradiol (E2),osteocalcin (BGP) and carboxy-terminal collagen crosslinks (CTX) were measured using ELISA.Gene expression profile was determined with microarray.Mouse osteoblast cells (MC3T3-E1) were used for in vitro study.Proliferation,differentiation and oxidative stress of the osteoblasts were investigated using MTT,qRT-PCR and biochemical methods.Results:In high cholesterol fed rats,the femur BMD and serum BGP level were significantly reduced,while the CTX level was significantly increased.DNA microarray analysis showed that 2290 genes were down-regulated and 992 genes were up-regulated in this group of rats.Of these genes,1626 were also down-regulated and 1466 were up-regulated in OVX rats.In total,370 genes were up-regulated in both groups,and 976 genes were down-regulated.Some of the down-regulated genes were found to code for proteins involved in the transforming growth factor beta (TGF-β)/bone morphogenic protein (BMP) and Wnt signaling pathways.The up-regulated genes were found to code for IL-6 and Ager with bone-resorption functions.Treatment of MC3T3-E1 cells with cholesterol (12.5-50μg/mL) inhibited the cell proliferation and differentiation in vitro in a concentration-dependent manner.The treatment also concentration-dependently reduced the expression of BMP2 and Cbfa1,and increased the oxidative injury in MC3T3-E1 cells.Conclusion:The results suggest a close

  8. CXCL1-Triggered Interaction of LFA1 and ICAM1 Control Glucose-Induced Leukocyte Recruitment during Inflammation In Vivo

    Directory of Open Access Journals (Sweden)

    Kirsten Buschmann

    2012-01-01

    Full Text Available It is well acknowledged that proinflammatory stimulation during acute hyperglycemia is able to aggravate inflammatory diseases. However, the mechanisms of proinflammatory effects of glucose are controversially discussed. We investigated leukocyte recruitment after intravenous injection of glucose in different inflammatory models using intravital microscopy. Flow chamber experiments, expression analysis, functional depletion, and knockout of key adhesion molecules gave mechanistic insight in involved pathways. We demonstrated that a single injection of glucose rapidly increased blood glucose levels in a dose-dependent manner. Notably, during tumor necrosis factor (TNF α-induced inflammation leukocyte recruitment was not further enhanced by glucose administration, whereas glucose injection profoundly augmented leukocyte adhesion and transmigration into inflamed tissue in the trauma model, indicating that proinflammatory properties of glucose are stimulus dependent. Experiments with functional or genetic inhibition of the chemokine receptor CXCR2, intercellular adhesion molecule 1 (ICAM1, and lymphocyte function antigen 1 (LFA1 suggest that keratino-derived-chemokine CXCL1-triggered interactions of ICAM1 and LFA1 are crucially involved in the trauma model of inflammation. The lacking effect of glucose on β2 integrin expression and on leukocyte adhesion in dynamic flow chamber experiments argues against leukocyte-driven underlying mechanisms and favours an endothelial pathway since endothelial ICAM1 expression was significantly upregulated in response to glucose.

  9. Modified ADM1 for modeling free ammonia inhibition in anaerobic acidogenic fermentation with high-solid sludge.

    Science.gov (United States)

    Bai, Jie; Liu, He; Yin, Bo; Ma, Huijun; Chen, Xinchun

    2017-02-01

    Anaerobic acidogenic fermentation with high-solid sludge is a promising method for volatile fatty acid (VFA) production to realize resource recovery. In this study, to model inhibition by free ammonia in high-solid sludge fermentation, the anaerobic digestion model No. 1 (ADM1) was modified to simulate the VFA generation in batch, semi-continuous and full scale sludge. The ADM1 was operated on the platform AQUASIM 2.0. Three kinds of inhibition forms, e.g., simple inhibition, Monod and non-inhibition forms, were integrated into the ADM1 and tested with the real experimental data for batch and semi-continuous fermentation, respectively. The improved particle swarm optimization technique was used for kinetic parameter estimation using the software MATLAB 7.0. In the modified ADM1, the Ks of acetate is 0.025, the km,ac is 12.51, and the KI_NH3 is 0.02, respectively. The results showed that the simple inhibition model could simulate the VFA generation accurately while the Monod model was the better inhibition kinetics form in semi-continuous fermentation at pH10.0. Finally, the modified ADM1 could successfully describe the VFA generation and ammonia accumulation in a 30m(3) full-scale sludge fermentation reactor, indicating that the developed model can be applicable in high-solid sludge anaerobic fermentation. Copyright © 2016. Published by Elsevier B.V.

  10. Myeloperoxidase-oxidized high density lipoprotein impairs atherosclerotic plaque stability by inhibiting smooth muscle cell migration.

    Science.gov (United States)

    Zhou, Boda; Zu, Lingyun; Chen, Yong; Zheng, Xilong; Wang, Yuhui; Pan, Bing; Dong, Min; Zhou, Enchen; Zhao, Mingming; Zhang, Youyi; Zheng, Lemin; Gao, Wei

    2017-01-10

    High density lipoprotein (HDL) has been proved to be a protective factor for coronary heart disease. Notably, HDL in atherosclerotic plaques can be nitrated (NO2-oxHDL) and chlorinated (Cl-oxHDL) by myeloperoxidase (MPO), likely compromising its cardiovascular protective effects. Here we determined the effects of NO2-oxHDL and Cl-oxHDL on SMC migration using wound healing and transwell assays, proliferation using MTT and BrdU assays, and apoptosis using Annexin-V assay in vitro, as well as on atherosclerotic plaque stability in vivo using a coratid artery collar implantation mice model. Our results showed that native HDL promoted SMC proliferation and migration, whereas NO2-oxHDL and Cl-oxHDL inhibited SMC migration and reduced capacity of stimulating SMC proliferation as well as migration, respectively. OxHDL had no significant influence on SMC apoptosis. In addition, we found that ERK1/2-phosphorylation was significantly lower when SMCs were incubated with NO2-oxHDL and Cl-oxHDL. Furthermore, transwell experiments showed that differences between native HDL, NO2-oxHDL and Cl-oxHDL was abolished after PD98059 (MAPK kinase inhibitor) treatment. In aortic SMCs from scavenger receptor BI (SR-BI) deficient mice, differences between migration of native HDL, NO2-oxHDL and Cl-oxHDL treated SMCs vanished, indicating SR-BI's possible role in HDL-associated SMC migration. Importantly, NO2-oxHDL and Cl-oxHDL induced neointima formation and reduced SMC positive staining cells in atherosclerotic plaque, resulting in elevated vulnerable index of atherosclerotic plaque. These findings implicate MPO-catalyzed oxidization of HDL may contribute to atherosclerotic plaque instability by inhibiting SMC proliferation and migration through MAPK-ERK pathway which was dependent on SR-BI.

  11. A rapamycin-releasing perivascular polymeric sheath produces highly effective inhibition of intimal hyperplasia.

    Science.gov (United States)

    Yu, Xiaohua; Takayama, Toshio; Goel, Shakti A; Shi, Xudong; Zhou, Yifan; Kent, K Craig; Murphy, William L; Guo, Lian-Wang

    2014-10-10

    Intimal hyperplasia produces restenosis (re-narrowing) of the vessel lumen following vascular intervention. Drugs that inhibit intimal hyperplasia have been developed, however there is currently no clinical method of perivascular drug-delivery to prevent restenosis following open surgical procedures. Here we report a poly(ε-caprolactone) (PCL) sheath that is highly effective in preventing intimal hyperplasia through perivascular delivery of rapamycin. We first screened a series of bioresorbable polymers, i.e., poly(lactide-co-glycolide) (PLGA), poly(lactic acid) (PLLA), PCL, and their blends, to identify desired release kinetics and sheath physical properties. Both PLGA and PLLA sheaths produced minimal (PBS buffer. In contrast, PCL sheaths exhibited more rapid and near-linear release kinetics, as well as durable integrity (>90days) as evidenced in both scanning electron microscopy and subcutaneous embedding experiments. Moreover, a PCL sheath deployed around balloon-injured rat carotid arteries was associated with a minimum rate of thrombosis compared to PLGA and PLLA. Morphometric analysis and immunohistochemistry revealed that rapamycin-loaded perivascular PCL sheaths produced pronounced (85%) inhibition of intimal hyperplasia (0.15±0.05 vs 1.01±0.16), without impairment of the luminal endothelium, the vessel's anti-thrombotic layer. Our data collectively show that a rapamycin-loaded PCL delivery system produces substantial mitigation of neointima, likely due to its favorable physical properties leading to a stable yet flexible perivascular sheath and steady and prolonged release kinetics. Thus, a PCL sheath may provide useful scaffolding for devising effective perivascular drug delivery particularly suited for preventing restenosis following open vascular surgery.

  12. 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.

  13. Cytochrome P450 2C24: expression, tissue distribution, high-throughput assay, and pharmacological inhibition

    Directory of Open Access Journals (Sweden)

    Jun Yang

    2012-04-01

    Full Text Available Cytochrome P450 (CYP-mediated epoxidation of arachidonic acid (AA contributes to important biological functions, including the pain-relieving responses produced by analgesic drugs. However, the relevant epoxygenase(s remain unidentified. Presently, we describe the tissue distribution, high-throughput assay, and pharmacological characteristics of the rat epoxygenase CYP2C24. Following cloning from male rat liver, recombinant baculovirus containing the C-terminal His-tagged cDNA was constructed and used to express the protein in Spodoptera frugiperda (Sf9 cells. Enzymatic activity was detected with membranes, NADPH regenerating system and CYP reductase, and optimized for high throughput screening by use of the Vivid Blue© BOMCC fluorescence substrate. Quantitative real-time PCR identified CYP2C24 m-RNA in liver, kidney, heart, lung, gonad and brain. Screening of CYP2C24 activity against a panel of inhibitors showed a very strong correlation with activity against the human homologue CYP2C19. In agreement with recent findings on CYP2C19, the epoxygenase blockers PPOH and MS-PPOH inhibited CYP2C24 only weakly, confirming that these drugs are not universal epoxygenase inhibitors. Finally, comparisons of the CYP2C24 inhibitor profile with anti-analgesic activity suggests that this isoform does not contribute to brain analgesic drug action. The present methods and pharmacological data will aid in study of the biological significance of this CYP isoform.

  14. Inhibition of Diethylnitrosamine-Induced Hepatocarcinogenesis in Mice by a High Dietary Protein Intake.

    Science.gov (United States)

    Shou, Qiyang; Chen, Fangming; Cai, Yueqin; Zhang, Shanxin; Tu, Jue; Zhang, Lizong; Wang, Dejun; Wang, Jianchao; Chen, Minli; Fu, Huiying

    2015-01-01

    Epidemiological and experimental evidence supports the key role of diet in the development of many types of cancer. Recent studies have suggested that dietary modifications may be beneficial for individuals at high risk for hepatocellular carcinoma (HCC). In this study, we investigated the effect of a high-protein (HP; 20% casein) dietondiethylnitrosamine (DEN)-induced hepatocarcinogenesis. Mice were given free access to water with 30 μg/ml DEN and fed a normal or HP diet for 22 wk. The results showed mice consuming HP diets had reduced mortality rates and body weights and lower hepatic enzyme activity compared to DEN-treated mice on a normal diet. HP consumption also promoted collagen accumulation in the liver, and reduced numbers of proliferating hepatocytes and infiltrating inflammatory cells, as well as decreased expression of inflammatory factor interleukin-1β, and nuclear factor κB activation. These data indicate that HP diets can inhibit DEN-induced hepatocarcinogenesis via suppression of the inflammatory response and provide a new evidence for the dietary management of clinical patients with hepatocellular carcinoma.

  15. Highly efficient inhibition of human immunodeficiency virus type 1 reverse transcriptase by aptamers functionalized gold nanoparticles

    Science.gov (United States)

    Shiang, Yen-Chun; Ou, Chung-Mao; Chen, Shih-Ju; Ou, Ting-Yu; Lin, Han-Jia; Huang, Chih-Ching; Chang, Huan-Tsung

    2013-03-01

    We have developed aptamer (Apt)-conjugated gold nanoparticles (Apt-Au NPs, 13 nm in diameter) as highly effective inhibitors for human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT). Two Apts, RT1t49 (Aptpol) and ODN 93 (AptRH), which recognize the polymerase and RNase H regions of HIV-1 RT, are used to conjugate Au NPs to prepare Aptpol-Au NPs and AptRH-Au NPs, respectively. In addition to DNA sequence, the surface density of the aptamers on Au NPs (nApt-Au NPs; n is the number of aptamer molecules on each Au NP) and the linker length number (Tm; m is the base number of the deoxythymidine linker) between the aptamer and Au NPs play important roles in determining their inhibition activity. A HIV-lentiviral vector-based antiviral assay has been applied to determine the inhibitory effect of aptamers or Apt-Au NPs on the early stages of their replication cycle. The nuclease-stable G-quadruplex structure of 40AptRH-T45-Au NPs shows inhibitory efficiency in the retroviral replication cycle with a decreasing infectivity (40.2%).We have developed aptamer (Apt)-conjugated gold nanoparticles (Apt-Au NPs, 13 nm in diameter) as highly effective inhibitors for human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT). Two Apts, RT1t49 (Aptpol) and ODN 93 (AptRH), which recognize the polymerase and RNase H regions of HIV-1 RT, are used to conjugate Au NPs to prepare Aptpol-Au NPs and AptRH-Au NPs, respectively. In addition to DNA sequence, the surface density of the aptamers on Au NPs (nApt-Au NPs; n is the number of aptamer molecules on each Au NP) and the linker length number (Tm; m is the base number of the deoxythymidine linker) between the aptamer and Au NPs play important roles in determining their inhibition activity. A HIV-lentiviral vector-based antiviral assay has been applied to determine the inhibitory effect of aptamers or Apt-Au NPs on the early stages of their replication cycle. The nuclease-stable G-quadruplex structure of 40AptRH-T45

  16. Curcumin modified silver nanoparticles for highly efficient inhibition of respiratory syncytial virus infection

    Science.gov (United States)

    Yang, Xiao Xi; Li, Chun Mei; Huang, Cheng Zhi

    2016-01-01

    Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition effect against respiratory syncytial virus (RSV) infection, giving a decrease of viral titers about two orders of magnitude at the concentration of cAgNPs under which no toxicity was found to the host cells. Mechanism investigations showed that cAgNPs could prevent RSV from infecting the host cells by inactivating the virus directly, indicating that cAgNPs are a novel promising efficient virucide for RSV.Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition

  17. Soy protein isolate inhibits hepatic tumor promotion in mice fed a high-fat liquid diet.

    Science.gov (United States)

    Mercer, Kelly E; Pulliam, Casey F; Pedersen, Kim B; Hennings, Leah; Ronis, Martin Jj

    2017-03-01

    Alcoholic and nonalcoholic fatty liver diseases are risk factors for development of hepatocellular carcinoma, but the underlying mechanisms are poorly understood. On the other hand, ingestion of soy-containing diets may oppose the development of certain cancers. We previously reported that replacing casein with a soy protein isolate reduced tumor promotion in the livers of mice with alcoholic liver disease after feeding a high fat ethanol liquid diet following initiation with diethylnitrosamine. Feeding soy protein isolate inhibited processes that may contribute to tumor promotion including inflammation, sphingolipid signaling, and Wnt/β-catenin signaling. We have extended these studies to characterize liver tumor promotion in a model of nonalcoholic fatty liver disease produced by chronic feeding of high-fat liquid diets in the absence of ethanol. Mice treated with diethylnitrosamine on postnatal day 14 were fed a high-fat liquid diet made with casein or SPI as the sole protein source for 16 weeks in adulthood. Relative to mice fed normal chow, a high fat/casein diet led to increased tumor promotion, hepatocyte proliferation, steatosis, and inflammation. Replacing casein with soy protein isolate counteracted these effects. The high fat diets also resulted in a general increase in transcripts for Wnt/β-catenin pathway components, which may be an important mechanism, whereby hepatic tumorigenesis is promoted. However, soy protein isolate did not block Wnt signaling in this nonalcoholic fatty liver disease model. We conclude that replacing casein with soy protein isolate blocks development of steatosis, inflammation, and tumor promotion in diethylnitrosamine-treated mice fed high fat diets. Impact statement The impact of dietary components on cancer is a topic of great interest for both the general public and the scientific community. Liver cancer is currently the second leading form of cancer deaths worldwide. Our study has addressed the effect of the protein

  18. Biphasic effect of alpha-linolenic acid on glucose-induced dysmorphogenesis and lipoperoxidation in whole rat embryo in culture.

    Science.gov (United States)

    Chirino-Galindo, Gladys; Barrera-Argüelles, Jorge-Israel; Trejo-González, Ninna-Leslie; Mejía-Zepeda, Ricardo; Palomar-Morales, Martín

    2017-03-18

    Type 1 diabetes mellitus complicated with pregnancy, know as diabetic embryopathy, is the cause of neonatal malformations and low for gestational age neonates. With the use of the whole-embryo culture system, it has been demonstrated that high glucose causes embryo dysmorphogenesis, and that oxidative stress appears to be the main mechanism. In recent years, beneficial effect of omega-3 fatty acids has been demonstrated in various diabetic models, and in diabetic complications. Since diabetic embryopathy is mediated probably through membrane lipoperoxidation, This study was designed to find if omega-3 fatty acids could ameliorate the effect of high glucose over the dysmorphogenesis of whole rat embryo in culture. Postimplantational rat embryos were cultured in hyperglycemic media, with addition of alpha-linolenic acid, and morphologic and morphometric parameters were registered. Also, lipoperoxidation and fatty acids composition were measured in cultured embryos. Growth of embryos cultured in presence of glucose was very affected, whereas lipoperoxidation was increased, and it was found that Triton X-100 causes similar results than glucose. Addition of low micromolar doses of alpha-linolenic acid overcome the effect of high glucose or Triton X-100, but higher doses does not ameliorates the effects of the carbohydrate or the detergent. Paradoxically, there are not significant changes in fatty acids composition, although the U/S fatty acids ratio shows an increasing tendency by high glucose and a normalizing tendency by omega-3 fatty acids. In conclusion, glucose and Triton X-100 induces in vitro dysmorphogenesis in post-implantational rat embryos associated with increased lipoperoxidation; and this nocive effect could be ameliorated by low micromolar doses of ALA.

  19. Osmotic induction of calcium accumulation in human embryonic kidney cells detected with a high sensitivity FRET calcium sensor.

    Science.gov (United States)

    Hou, Bi-Huei; Takanaga, Hitomi; Griesbeck, Oliver; Frommer, Wolf B

    2009-08-01

    Calcium serves as a second messenger in glucose-triggered insulin secretion of pancreatic cells. Less is known about sugar signaling in non-excitable cells. Here, the high sensitivity FRET calcium sensor TN-XXL was used to characterize glucose-induced calcium responses in non-excitable human embryonic kidney HEK293T cells. HEK293T cells responded to perfusion with glucose with a sustained and concentration-dependent increase in cytosolic calcium levels. Sucrose and mannitol triggered comparable calcium responses, suggesting that the increase of the calcium concentration was caused by osmotic effects. HEK293T cells are characterized by low endogenous glucose uptake capacity as shown with a high sensitivity glucose sensor. Consistently, when glucose influx was artificially increased by co-expression of GLUT glucose transporters, the glucose-induced calcium increase was significantly reduced. Neither calcium depletion, nor gadolinium or thapsigargin were able to inhibit the calcium accumulation. Taken together, membrane impermeable osmolytes such as sucrose and mannitol lead to an increase in calcium levels, while the effect of glucose depends on the cell's glucose uptake capacity and will thus vary between cell types in the body that differ in their glucose uptake capacity.

  20. High-dose insulin inhibits gap junction intercellular communication in vascular smooth muscle cells.

    Science.gov (United States)

    Bian, Ou; Zhang, Haishan; Guan, Qigang; Sun, Yingxian; Zeng, Dingyin

    2015-07-01

    Gap junction intercellular communication (GJIC) is important in mediating intercellular substance and signal transmission. Connexin (Cx)43 is a major component involved in GJIC in vascular tissue and its abnormal expression is closely associated with various vascular diseases. Insulin resistance is the central component of metabolic syndrome, and high doses of insulin can affect vascular function through multiple pathways, resulting in cardiovascular disease. However, the effects of insulin on GJIC function and connexin (Cx)43 expression in vascular smooth muscle cells (VSMCs) remain unclear. Following treatment of VSMCs with different doses of insulin, a fluorescence recovery after photobleaching (FRAP) assay was performed to evaluate GJIC function in treated VSMCs. The results showed that high‑dose insulin suppressed GJIC function. Western blot assays further demonstrated that high‑dose insulin induced the phosphorylation of Cx43 at s368 and downregulated the expression of Cx43. H2O2 release assays demonstrated that high‑dose insulin treatment significantly elevated the cellular H2O2 level. In addition, compared with cells treated with high‑dose insulin, pretreatment with catalase significantly restored the cellular GJIC function, decreased the phosphorylation level of Cx43 at s368, and enhanced Cx43 expression. In conclusion, these data indicate that high‑dose insulin inhibits cellular GJIC function through the oxidative stress‑activated signaling pathway. This phenomenon may also constitute a potential mechanism underlying the pathogenesis of insulin resistance and its complications.

  1. High-intensity sprint training inhibits mitochondrial respiration through aconitase inactivation.

    Science.gov (United States)

    Larsen, Filip J; Schiffer, Tomas A; Ørtenblad, Niels; Zinner, Christoph; Morales-Alamo, David; Willis, Sarah J; Calbet, Jose A; Holmberg, Hans-Christer; Boushel, Robert

    2016-01-01

    Intense exercise training is a powerful stimulus that activates mitochondrial biogenesis pathways and thus increases mitochondrial density and oxidative capacity. Moderate levels of reactive oxygen species (ROS) during exercise are considered vital in the adaptive response, but high ROS production is a serious threat to cellular homeostasis. Although biochemical markers of the transition from adaptive to maladaptive ROS stress are lacking, it is likely mediated by redox sensitive enzymes involved in oxidative metabolism. One potential enzyme mediating such redox sensitivity is the citric acid cycle enzyme aconitase. In this study, we examined biopsy specimens of vastus lateralis and triceps brachii in healthy volunteers, together with primary human myotubes. An intense exercise regimen inactivated aconitase by 55-72%, resulting in inhibition of mitochondrial respiration by 50-65%. In the vastus, the mitochondrial dysfunction was compensated for by a 15-72% increase in mitochondrial proteins, whereas H2O2 emission was unchanged. In parallel with the inactivation of aconitase, the intermediary metabolite citrate accumulated and played an integral part in cellular protection against oxidative stress. In contrast, the triceps failed to increase mitochondrial density, and citrate did not accumulate. Instead, mitochondrial H2O2 emission was decreased to 40% of the pretraining levels, together with a 6-fold increase in protein abundance of catalase. In this study, a novel mitochondrial stress response was highlighted where accumulation of citrate acted to preserve the redox status of the cell during periods of intense exercise.

  2. Synaptotagmin-7 as a positive regulator of glucose-induced glucagon-like peptide-1 secretion in mice

    DEFF Research Database (Denmark)

    Gustavsson, N; Wang, Y; Kang, Y

    2011-01-01

    . Lentiviral knockdown (KD) of synaptotagmin-7 in GLUTag cells led to similar reductions in GLP-1 secretion, as determined by biochemical assays and by membrane capacitance measurements. Calcium response was not altered in synaptotagmin-7 KD cells. CONCLUSIONS/INTERPRETATION: These results demonstrate......AIMS/HYPOTHESIS: Glucagon-like peptide-1 (GLP-1), a hormone with potent antihyperglycaemic effects, is produced and secreted from highly specialised gut endocrine L-cells. It regulates glucose homeostasis by promoting glucose-dependent insulin secretion, suppressing glucagon secretion and enhancing...... insulin sensitivity. Similar to islet alpha and beta cells, L-cells are electrically excitable, and express calcium channels and ATP-sensitive potassium channels. GLP-1 is also stored in secretory granules, the exocytosis of which is triggered by increased intracellular calcium levels. Although...

  3. (-)-Epigallocatechin-3-gallate inhibits pancreatic lipase and reduces body weight gain in high fat-fed obese mice.

    Science.gov (United States)

    Grove, Kimberly A; Sae-tan, Sudathip; Kennett, Mary J; Lambert, Joshua D

    2012-11-01

    Tea (Camellia sinensis, Theaceae) has been shown to have obesity preventive effects in laboratory studies. We hypothesized that dietary epigallocatechin-3-gallate (EGCG) could reverse metabolic syndrome in high fat-fed obese C57bl/6J mice, and that these effects were related to inhibition of pancreatic lipase (PL). Following treatment with 0.32% EGCG for 6 weeks, a 44% decrease in body weight (BW) gain in high fat-fed, obese mice (P EGCG treatment increased fecal lipid content by 29.4% (P fat-fed control, whereas in vitro, EGCG dose-dependently inhibited PL (IC(50) = 7.5 µmol/l) in a noncompetitive manner with respect to substrate concentration. (-)-Epicatechin-3-gallate exhibited similar inhibitory activity, whereas the nonester-containing (-)-epigallocatechin did not. In conclusion, EGCG supplementation reduced final BW and BW gain in obese mice, and some of these effects may be due to inhibition of PL by EGCG.

  4. 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.

  5. Insulin/glucose induces natriuretic peptide clearance receptor in human adipocytes: a metabolic link with the cardiac natriuretic pathway.

    Science.gov (United States)

    Bordicchia, M; Ceresiani, M; Pavani, M; Minardi, D; Polito, M; Wabitsch, M; Cannone, V; Burnett, J C; Dessì-Fulgheri, P; Sarzani, R

    2016-07-01

    Cardiac natriuretic peptides (NP) are involved in cardiorenal regulation and in lipolysis. The NP activity is largely dependent on the ratio between the signaling receptor NPRA and the clearance receptor NPRC. Lipolysis increases when NPRC is reduced by starving or very-low-calorie diet. On the contrary, insulin is an antilipolytic hormone that increases sodium retention, suggesting a possible functional link with NP. We examined the insulin-mediated regulation of NP receptors in differentiated human adipocytes and tested the association of NP receptor expression in visceral adipose tissue (VAT) with metabolic profiles of patients undergoing renal surgery. Differentiated human adipocytes from VAT and Simpson-Golabi-Behmel Syndrome (SGBS) adipocyte cell line were treated with insulin in the presence of high-glucose or low-glucose media to study NP receptors and insulin/glucose-regulated pathways. Fasting blood samples and VAT samples were taken from patients on the day of renal surgery. We observed a potent insulin-mediated and glucose-dependent upregulation of NPRC, through the phosphatidylinositol 3-kinase pathway, associated with lower lipolysis in differentiated adipocytes. No effect was observed on NPRA. Low-glucose medium, used to simulate in vivo starving conditions, hampered the insulin effect on NPRC through modulation of insulin/glucose-regulated pathways, allowing atrial natriuretic peptide to induce lipolysis and thermogenic genes. An expression ratio in favor of NPRC in adipose tissue was associated with higher fasting insulinemia, HOMA-IR, and atherogenic lipid levels. Insulin/glucose-dependent NPRC induction in adipocytes might be a key factor linking hyperinsulinemia, metabolic syndrome, and higher blood pressure by reducing NP effects on adipocytes. Copyright © 2016 the American Physiological Society.

  6. Dynamics of glucose-induced membrane recruitment of protein kinase C beta II in living pancreatic islet beta-cells.

    Science.gov (United States)

    Pinton, Paolo; Tsuboi, Takashi; Ainscow, Edward K; Pozzan, Tullio; Rizzuto, Rosario; Rutter, Guy A

    2002-10-01

    The mechanisms by which glucose may affect protein kinase C (PKC) activity in the pancreatic islet beta-cell are presently unclear. By developing adenovirally expressed chimeras encoding fusion proteins between green fluorescent protein and conventional (betaII), novel (delta), or atypical (zeta) PKCs, we show that glucose selectively alters the subcellular localization of these enzymes dynamically in primary islet and MIN6 beta-cells. Examined by laser scanning confocal or total internal reflection fluorescence microscopy, elevated glucose concentrations induced oscillatory translocations of PKCbetaII to spatially confined regions of the plasma membrane. Suggesting that increases in free cytosolic Ca(2+) concentrations ([Ca(2+)](c)) were primarily responsible, prevention of [Ca(2+)](c) increases with EGTA or diazoxide completely eliminated membrane recruitment, whereas elevation of cytosolic [Ca(2+)](c) with KCl or tolbutamide was highly effective in redistributing PKCbetaII both to the plasma membrane and to the surface of dense core secretory vesicles. By contrast, the distribution of PKCdelta.EGFP, which binds diacylglycerol but not Ca(2+), was unaffected by glucose. Measurement of [Ca(2+)](c) immediately beneath the plasma membrane with a ratiometric "pericam," fused to synaptic vesicle-associated protein-25, revealed that depolarization induced significantly larger increases in [Ca(2+)](c) in this domain. These data demonstrate that nutrient stimulation of beta-cells causes spatially and temporally complex changes in the subcellular localization of PKCbetaII, possibly resulting from the generation of Ca(2+) microdomains. Localized changes in PKCbetaII activity may thus have a role in the spatial control of insulin exocytosis.

  7. A Preliminary Transcranial Magnetic Stimulation Study of Cortical Inhibition and Excitability in High-Functioning Autism and Asperger Disorder

    Science.gov (United States)

    Enticott, Peter G.; Rinehart, Nicole J.; Tonge, Bruce J.; Bradshaw, John L.; Fitzgerald, Paul B.

    2010-01-01

    Aim: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Method: Participants were diagnosed by…

  8. Event-rate manipulation and its effect on arousal modulation and response inhibition in adults with high functioning autism

    NARCIS (Netherlands)

    Raymaekers, R; van der Meere, J; Roeyers, H

    2004-01-01

    The aim of the current study was to evaluate arousal modulation and response inhibition in adults with high functioning autism (HFA). Using a go/no-go paradigm with varying presentation rate, it was found that performance efficiency (Mean RT, Standard Deviation of RT and Errors of Commission) in adu

  9. A Preliminary Transcranial Magnetic Stimulation Study of Cortical Inhibition and Excitability in High-Functioning Autism and Asperger Disorder

    Science.gov (United States)

    Enticott, Peter G.; Rinehart, Nicole J.; Tonge, Bruce J.; Bradshaw, John L.; Fitzgerald, Paul B.

    2010-01-01

    Aim: Controversy surrounds the distinction between high-functioning autism (HFA) and Asperger disorder, but motor abnormalities are associated features of both conditions. This study examined motor cortical inhibition and excitability in HFA and Asperger disorder using transcranial magnetic stimulation (TMS). Method: Participants were diagnosed by…

  10. Modulation of low-density lipoprotein-induced inhibition of intercellular communication by antioxidants and high-density lipoproteins

    NARCIS (Netherlands)

    Zwijsen, R M; de Haan, L. H. J.; Kuivenhoven, J A; Nusselder, I C

    1991-01-01

    In order to study the capacity of antioxidants and high-density lipoproteins (HDL) to modulate the effects of low-density lipoprotein (LDL) on intercellular communication, arterial smooth muscle cells and a dye transfer method were used. LDL, in contrast to HDL, inhibited the communication between a

  11. Modulation of low-density lipoprotein-induced inhibition of intercellular communication by antioxidants and high-density lipoproteins

    NARCIS (Netherlands)

    Zwijsen, R M; de Haan, L. H. J.; Kuivenhoven, J A; Nusselder, I C

    In order to study the capacity of antioxidants and high-density lipoproteins (HDL) to modulate the effects of low-density lipoprotein (LDL) on intercellular communication, arterial smooth muscle cells and a dye transfer method were used. LDL, in contrast to HDL, inhibited the communication between

  12. Prepulse inhibition and latent inhibition deficits in Roman high-avoidance vs. Roman low-avoidance rats: Modeling schizophrenia-related features.

    Science.gov (United States)

    Esnal, Aitor; Sánchez-González, Ana; Río-Álamos, Cristóbal; Oliveras, Ignasi; Cañete, Toni; Blázquez, Gloria; Tobeña, Adolf; Fernández-Teruel, Alberto

    2016-09-01

    The aim of the present study was to obtain further evidence supporting the validity of a new genetically-based rat model for the study of schizophrenia-relevant symptoms. The Roman high- (RHA-I) and low-avoidance (RLA-I) inbred rats have been psychogenetically selected for their rapid versus extremely poor acquisition of the two-way avoidance task in the shuttle box and present two well-differentiated profiles regarding several traits related to anxiety, impulsivity and sensitivity to (dopaminergic) psychostimulants. In this study we have tested animals from both strains in two behavioral paradigms that are related to schizophrenia, i.e. prepulse inhibition (PPI) and latent inhibition (LI) of fear-potentiated startle (FPS). The results show that while RLA-I rats display good PPI and LI to the context, RHA-Is show an impairment of PPI and no sign of an LI effect, which goes in the direction of the results obtained in schizophrenic patients. Therefore, although further behavioral and psychopharmacological work needs to be done, the present findings and previous studies carried out in our laboratory and others allow us to propose the RHA-I rat strain as a putative genetic rat model of differential schizophrenia-related features.

  13. Changes in glucose-induced plasma active glucagon-like peptide-1 levels by co-administration of sodium-glucose cotransporter inhibitors with dipeptidyl peptidase-4 inhibitors in rodents.

    Science.gov (United States)

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

    2016-12-01

    We investigated whether structurally different sodium-glucose cotransporter (SGLT) 2 inhibitors, when co-administered with dipeptidyl peptidase-4 (DPP4) inhibitors, could enhance glucagon-like peptide-1 (GLP-1) secretion during oral glucose tolerance tests (OGTTs) in rodents. Three different SGLT inhibitors-1-(β-d-Glucopyranosyl)-4-chloro-3-[5-(6-fluoro-2-pyridyl)-2-thienylmethyl]benzene (GTB), TA-1887, and canagliflozin-were examined to assess the effect of chemical structure. Oral treatment with GTB plus a DPP4 inhibitor enhanced glucose-induced plasma active GLP-1 (aGLP-1) elevation and suppressed glucose excursions in both normal and diabetic rodents. In DPP4-deficient rats, GTB enhanced glucose-induced aGLP-1 elevation without affecting the basal level, whereas metformin, previously reported to enhance GLP-1 secretion, increased both the basal level and glucose-induced elevation. Oral treatment with canagliflozin and TA-1887 also enhanced glucose-induced aGLP-1 elevation when co-administered with either teneligliptin or sitagliptin. These data suggest that structurally different SGLT2 inhibitors enhance plasma aGLP-1 elevation and suppress glucose excursions during OGTT when co-administered with DPP4 inhibitors, regardless of the difference in chemical structure. Combination treatment with DPP4 inhibitors and SGLT2 inhibitors having moderate SGLT1 inhibitory activity may be a promising therapeutic option for improving glycemic control in patients with type 2 diabetes mellitus. Copyright © 2016 The Authors. Production and hosting by Elsevier B.V. All rights reserved.

  14. Photoyellowing inhibition of bleached high yield pulps using novel water-soluble UV screens.

    Science.gov (United States)

    Argyropoulos, D S; Halevy, P; Peng, P

    2000-02-01

    To address the deficiencies of benzophenone UV screens for preventing brightness reversion in high yield mechanical papers, we synthesized a new series of such materials with enhanced water solubility and compatibility with the lignocellulosic substrate. A series of 2,4-dihydroxybenzophenones (DHB) were synthesized containing various Mannich bases at the C3 position of one of its rings. They possess the UV-screening ability of o-hydroxylbenzophenones, and they also contain tertiary nitrogen atoms that may function as radical scavengers. Aqueous solutions of the hydrochloride salt of 3-(dimethylaminomethylene)-2,4-dihydroxylbenzophenone (1), when applied on bleached chemithermomechanical pulp (CTMP) sheets, were significantly more efficient in preventing photoyellowing than the original DHB applied on the sheets from ethanol-water solutions. This confirmed our original hypothesis that increasing the compatibility of the UV screen with the lignocellulosic matrix would increase its efficiency in preventing photoyellowing. Compound 1, however, was found to be somewhat more effective than its hydrochloride salt toward preventing photoyellowing. This was attributed to the synergistic action of the free tertiary aminic center attached on the molecule with its UV-screening ability. To comprehend further the various parameters that influence the photoyellowing inhibition performance of these compounds and DHB with bleached CTMP pulp fibers, a series of handsheets were prepared at different pH. The interactions of the protonated compound 1 with pulp fibers were then evaluated by studying their kinetics of absorption and desorption to and from the fiber matrix. This part of our study found that the adsorption of protonated Mannich derivatives of DHB onto pulp is most likely governed by a cation-exchange mechanism involving the cationic amine group with the sulfonic and carboxylic acid groups located on the surface of the fibers. The pH the paper sheet was made from was also

  15. 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.

  16. Farnesoid X Receptor Inhibits the Transcriptional Activity of Carbohydrate Response Element Binding Protein in Human Hepatocytes

    Science.gov (United States)

    Caron, Sandrine; Huaman Samanez, Carolina; Dehondt, Hélène; Ploton, Maheul; Briand, Olivier; Lien, Fleur; Dorchies, Emilie; Dumont, Julie; Postic, Catherine; Cariou, Bertrand; Lefebvre, Philippe

    2013-01-01

    The glucose-activated transcription factor carbohydrate response element binding protein (ChREBP) induces the expression of hepatic glycolytic and lipogenic genes. The farnesoid X receptor (FXR) is a nuclear bile acid receptor controlling bile acid, lipid, and glucose homeostasis. FXR negatively regulates hepatic glycolysis and lipogenesis in mouse liver. The aim of this study was to determine whether FXR regulates the transcriptional activity of ChREBP in human hepatocytes and to unravel the underlying molecular mechanisms. Agonist-activated FXR inhibits glucose-induced transcription of several glycolytic genes, including the liver-type pyruvate kinase gene (L-PK), in the immortalized human hepatocyte (IHH) and HepaRG cell lines. This inhibition requires the L4L3 region of the L-PK promoter, known to bind the transcription factors ChREBP and hepatocyte nuclear factor 4α (HNF4α). FXR interacts directly with ChREBP and HNF4α proteins. Analysis of the protein complex bound to the L4L3 region reveals the presence of ChREBP, HNF4α, FXR, and the transcriptional coactivators p300 and CBP at high glucose concentrations. FXR activation does not affect either FXR or HNF4α binding to the L4L3 region but does result in the concomitant release of ChREBP, p300, and CBP and in the recruitment of the transcriptional corepressor SMRT. Thus, FXR transrepresses the expression of genes involved in glycolysis in human hepatocytes. PMID:23530060

  17. Inhibition Underlies the Effect of High Need for Closure on Cultural Closed-Mindedness under Mortality Salience.

    Science.gov (United States)

    Agroskin, Dmitrij; Jonas, Eva; Klackl, Johannes; Prentice, Mike

    2016-01-01

    The hypothesis that people respond to reminders of mortality with closed-minded, ethnocentric attitudes has received extensive empirical support, largely from research in the Terror Management Theory (TMT) tradition. However, the basic motivational and neural processes that underlie this effect remain largely hypothetical. According to recent neuropsychological theorizing, mortality salience (MS) effects on cultural closed-mindedness may be mediated by activity in the behavioral inhibition system (BIS), which leads to passive avoidance and decreased approach motivation. This should be especially true for people motivated to avoid unfamiliar and potentially threatening stimuli as reflected in a high need for closure (NFC). In two studies involving moderated mediation analyses, people high on trait NFC responded to MS with increased BIS activity (as indicated by EEG and the line bisection task), which is characteristic of inhibited approach motivation. BIS activity, in turn, predicted a reluctance to explore foreign cultures (Study 1) and generalized ethnocentric attitudes (Study 2). In a third study, inhibition was induced directly and caused an increase in ethnocentrism for people high on NFC. Moreover, the effect of the inhibition manipulation × NFC interaction on ethnocentrism was explained by increases in BIS-related affect (i.e., anxious inhibition) at high NFC. To our knowledge, this research is the first to establish an empirical link between very basic, neurally-instantiated inhibitory processes and rather complex, higher-order manifestations of intergroup negativity in response to MS. Our findings contribute to a fuller understanding of the cultural worldview defense phenomenon by illuminating the motivational underpinnings of cultural closed-mindedness in the wake of existential threat.

  18. Inhibition Underlies the Effect of High Need for Closure on Cultural Closed-Mindedness under Mortality Salience

    Directory of Open Access Journals (Sweden)

    Dmitrij Agroskin

    2016-10-01

    Full Text Available The hypothesis that people respond to reminders of mortality with closed-minded, ethnocentric attitudes has received extensive empirical support, largely from research in the Terror Management theory tradition. However, the basic motivational and neural processes that underlie this effect remain largely hypothetical. According to recent neuropsychological theorizing, mortality salience (MS effects on cultural closed-mindedness may be mediated by activity in the behavioral inhibition system (BIS, which leads to passive avoidance and decreased approach motivation. This should be especially true for people motivated to avoid unfamiliar and potentially threatening stimuli as reflected in a high need for closure (NFC. In two studies involving moderated mediation analyses, people high on trait NFC responded to MS with increased BIS activity (as indicated by EEG and the line bisection task, which is characteristic of inhibited approach motivation. BIS activity, in turn, predicted a reluctance to explore foreign cultures (Study 1 and generalized ethnocentric attitudes (Study 2. In a third study, inhibition was induced directly and caused an increase in ethnocentrism for people high on NFC. Moreover, the effect of the inhibition manipulation × NCF interaction on ethnocentrism was explained by increases in BIS-related affect (i.e., anxious inhibition at high NFC. To our knowledge, this research is the first to establish an empirical link between very basic, neurally-instantiated inhibitory processes and rather complex, higher-order manifestations of intergroup negativity. Our findings contribute to a fuller understanding of the cultural worldview defense phenomenon by illuminating the motivational underpinnings of cultural closed-mindedness in the wake of existential threat.

  19. High-level inhibition of mitochondrial complexes III and IV is required to increase glutamate release from the nerve terminal

    LENUS (Irish Health Repository)

    Kilbride, Sean M

    2011-07-26

    Abstract Background The activities of mitochondrial complex III (ubiquinol-cytochrome c reductase, EC 1.10.2.2) and complex IV (cytochrome c oxidase EC 1.9.3.1) are reduced by 30-70% in Huntington\\'s disease and Alzheimer\\'s disease, respectively, and are associated with excitotoxic cell death in these disorders. In this study, we investigated the control that complexes III and complex IV exert on glutamate release from the isolated nerve terminal. Results Inhibition of complex III activity by 60-90% was necessary for a major increase in the rate of Ca2+-independent glutamate release to occur from isolated nerve terminals (synaptosomes) depolarized with 4-aminopyridine or KCl. Similarly, an 85-90% inhibition of complex IV activity was required before a major increase in the rate of Ca2+-independent glutamate release from depolarized synaptosomes was observed. Inhibition of complex III and IV activities by ~ 60% and above was required before rates of glutamate efflux from polarized synaptosomes were increased. Conclusions These results suggest that nerve terminal mitochondria possess high reserves of complex III and IV activity and that high inhibition thresholds must be reached before excess glutamate is released from the nerve terminal. The implications of the results in the context of the relationship between electron transport chain enzyme deficiencies and excitotoxicity in neurodegenerative disorders are discussed.

  20. Inhibition of the high affinity choline transporter enhances hyperalgesia in a rat model of chronic pancreatitis.

    Science.gov (United States)

    Luo, Dan; Chen, Lei; Yu, Baoping

    2017-06-17

    The mechanisms underlying chronic and persistent pain associated with chronic pancreatitis (CP) are not completely understood. The cholinergic system is one of the major neural pathways of the pancreas. Meanwhile, this system plays an important role in chronic pain. We hypothesized that the high affinity choline transporter CHT1, which is a main determinant of cholinergic signaling capacity, is involved in regulating pain associated with CP. CP was induced by intraductal injection of 2% trinitrobenzene sulfonic acid (TNBS) in Sprague-Dawley rats. Pathological examination was used to evaluate the inflammation of pancreas and hyperalgesia was assessed by measuring the number of withdrawal events evoked by application of the von Frey filaments. CHT1 expression in pancreas-specific dorsal root ganglia (DRGs) was assessed through immunohistochemistry and western blotting. We also intraperitoneally injected the rats with hemicholinium-3 (HC-3, a specific inhibitor of CHT1). Then we observed its effects on the visceral hyperalgesia induced by CP, and on the acetylcholine (ACh) levels in the DRGs through using an acetylcholine/acetylcholinesterase assay kit. Signs of CP were observed 21 days after TNBS injection. Rats subjected to TNBS infusions had increased sensitivity to mechanical stimulation of the abdomen. CHT1-immunoreactive cells were increased in the DRGs from rats with CP compared to naive or sham rats. Western blots indicated that CHT1 expression was significantly up-regulated in TNBS-treated rats when compared to naive or sham-operated rats at all time points following surgery. In the TNBS group, CHT1 expression was higher on day 28 than on day 7 or day 14, but there was no statistical difference in CHT1 expression on day 28 vs. day 21. Treatment with HC-3 (60 μg/kg, 80 μg/kg, or 100 μg/kg) markedly enhanced the mechanical hyperalgesia and reduced ACh levels in a dose-dependent manner in rats with CP. We report for the first time that CHT1 may be involved

  1. Polyphenols from Artemisia annua L Inhibit Adhesion and EMT of Highly Metastatic Breast Cancer Cells MDA-MB-231.

    Science.gov (United States)

    Ko, Young Shin; Lee, Won Sup; Panchanathan, Radha; Joo, Young Nak; Choi, Yung Hyun; Kim, Gon Sup; Jung, Jin-Myung; Ryu, Chung Ho; Shin, Sung Chul; Kim, Hye Jung

    2016-07-01

    Recent evidence suggests that polyphenolic compounds from plants have anti-invasion and anti-metastasis capabilities. The Korean annual weed, Artemisia annua L., has been used as a folk medicine for treatment of various diseases. Here, we isolated and characterized polyphenols from Korean A. annua L (pKAL). We investigated anti-metastatic effects of pKAL on the highly metastatic MDA-MB-231 breast cancer cells especially focusing on cancer cell adhesion to the endothelial cell and epithelial-mesenchymal transition (EMT). Firstly, pKAL inhibited cell viability of MDA-MB-231 cells in a dose-dependent manner, but not that of human umbilical vein endothelial cells (ECs). Polyphenols from Korean A. annua L inhibited the adhesion of MDA-MB-231 cells to ECs through reducing vascular cell adhesion molecule-1 expression of MDA-MB-231 and ECs, but not intracellular adhesion molecule-1 at the concentrations where pKAL did not influence the cell viability of either MDA-MB-231 cells nor EC. Further, pKAL inhibited tumor necrosis factor-activated MDA-MB-231 breast cancer cell invasion through inhibition of matrix metalloproteinase-2 and matrix metalloproteinase-9 and EMT. Moreover, pKAL inhibited phosphorylation of Akt, but not that of protein kinase C. These results suggest that pKAL may serve as a therapeutic agent against cancer metastasis at least in part by inhibiting the cancer cell adhesion to ECs through suppression of vascular cell adhesion molecule-1 and invasion through suppression of EMT. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

  2. Inhibition of intercellular communication by condensates of high and low tar cigarettes

    DEFF Research Database (Denmark)

    Vang, Ole; Wallin, Håkan; Autrup, Herman

    1995-01-01

    Inhibition of gap junctional intercellular communication (GJIC) is a predictive short term test for tumor promoting activity. A new metabolic cooperation assay has been developed, which takes the cytochrome P-450 metabolism into account. In this assay the inhibitory activity of tobacco smoke cond...... that compounds in the CSC act strongly synergistically. Furthermore, CSC and CSC fractions synergistically inhibit GJIC with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate, indicating different mechanisms of action....... no effect. The effect was only marginally greater in cells expressing different cytochrome P-450 enzymes, indicating that the active substances are not metabolized by these enzymes. The activities of CSC fractions were considerably lower than the activities in the unfractionated CSC. This may indicate...

  3. Hydrogen Sulfide Inhibits High-Salt Diet-Induced Renal Oxidative Stress and Kidney Injury in Dahl Rats

    Directory of Open Access Journals (Sweden)

    Pan Huang

    2016-01-01

    Full Text Available Background. The study was designed to investigate if H2S could inhibit high-salt diet-induced renal excessive oxidative stress and kidney injury in Dahl rats. Methods. Male salt-sensitive Dahl and SD rats were used. Blood pressure (BP, serum creatinine, urea, creatinine clearance rate, and 24-hour urine protein were measured. Renal ultra- and microstructures were observed. Collagen-I and -III contents the oxidants and antioxidants levels in renal tissue were detected. Keap1/Nrf2 association and Keap1 s-sulfhydration were detected. Results. After 8 weeks of high-salt diet, BP was significantly increased, renal function and structure were impaired, and collagen deposition was abundant in renal tissues with increased renal MPO activity, H2O2, MDA, GSSG, and •OH contents, reduced renal T-AOC and GSH contents, CAT, GSH-PX and SOD activity, and SOD expressions in Dahl rats. Furthermore, endogenous H2S in renal tissues was decreased in Dahl rats. H2S donor, however, decreased BP, improved renal function and structure, and inhibited collagen excessive deposition in kidney, in association with increased antioxidative activity and reduced oxidative stress in renal tissues. H2S activated Nrf2 by inducing Keap1 s-sulfhydration and subsequent Keap1/Nrf2 disassociation. Conclusions. H2S protected against high-salt diet-induced renal injury associated with enhanced antioxidant capacity and inhibited renal oxidative stress.

  4. Therapeutic inhibition of mitochondrial reactive oxygen species with mito-TEMPO reduces diabetic cardiomyopathy

    Science.gov (United States)

    Ni, Rui; Cao, Ting; Xiong, Sidong; Ma, Jian; Fan, Guo-Chang; Lacefield, James C.; Lu, Yanrong; Le Tissier, Sydney; Peng, Tianqing

    2016-01-01

    Aims The mitochondria are important sources of reactive oxygen species (ROS) in the heart. Mitochondrial ROS production has been implicated in the pathogenesis of diabetic cardiomyopathy, suggesting that therapeutic strategies specifically targeting mitochondrial ROS may have benefit in this disease. We investigated the therapeutic effects of mitochondria-targeted antioxidant mito-TEMPO on diabetic cardiomyopathy. Methods The mitochondria-targeted antioxidant mito-TEMPO was administrated after diabetes onset in a mouse model of streptozotocin-induced type-1 diabetes and type-2 diabetic db/db mice. Cardiac adverse changes were analyzed and myocardial function assessed. Cultured adult cardiomyocytes were stimulated with high glucose, and mitochondrial superoxide generation and cell death were measured. Results Incubation with high glucose increased mitochondria superoxide generation in cultured cardiomyocytes, which was prevented by mito-TEMPO. Co-incubation with mito-TEMPO abrogated high glucose-induced cell death. Mitochondrial ROS generation, and intracellular oxidative stress levels were induced in both type-1 and type-2 diabetic mouse hearts. Daily injection of mito-TEMPO for 30 days inhibited mitochondrial ROS generation, prevented intracellular oxidative stress levels, decreased apoptosis and reduced myocardial hypertrophy in diabetic hearts, leading to improvement of myocardial function in both type-1 and type-2 diabetic mice. Incubation with mito-TEMPO or inhibition of Nox2-containing NADPH oxidase prevented oxidative stress levels and cell death in high glucose-stimulated cardiomyocytes. Mechanistic study revealed that the protective effects of mito-TEMPO were associated with down-regulation of ERK1/2 phosphorylation. Conclusions Therapeutic inhibition of mitochondrial ROS by mito-TEMPO reduced adverse cardiac changes and mitigated myocardial dysfunction in diabetic mice. Thus, mitochondria-targeted antioxidants may be an effective therapy for diabetic

  5. Corrosion inhibition by inorganic cationic inhibitors on the high strength alumunium alloy, 2024-T3

    Science.gov (United States)

    Chilukuri, Anusha

    The toxicity and carcinogenic nature of chromates has led to the investigation of environmentally friendly compounds that offer good corrosion resistance to AA 2024-T3. Among the candidate inhibitors are rare earth metal cationic (REM) and zinc compounds, which have received much of attention over the past two decades. A comparative study on the corrosion inhibition caused by rare earth metal cations, Ce3+, Pr3+, La3+ and Zn2+ cations on the alloy was done. Cathodic polarization showed that these inhibitor ions suppress the oxygen reduction reaction (ORR) to varying extents with Zn2+ providing the best inhibition. Pr3+ exhibited windows of concentration (100-300 ppm) in which the corrosion rate is minimum; similar to the Ce3+ cation. Scanning Electron Microscopy (SEM) studies showed that the mechanism of inhibition of the Pr3+ ion is also similar to that of the Ce3+ ion. Potentiodynamic polarization experiments after 30 min immersion time showed greatest suppression of oxygen reduction reaction in neutral chloride solutions (pH 7), which reached a maximum at a Zn2+ ion concentration of 5 mM. Anodic polarization experiments after 30 min immersion time, showed no anodic inhibition by the inhibitor in any concentration (0.1 mM - 10 mM) and at any pH. However, anodic polarization of samples immersed after longer immersion times (upto 4 days) in mildly acidic Zn2+ (pH 4) solutions showed significant reduction in anodic kinetics indicating that zinc also acts as a “slow anodic inhibitor”. In contrast to the polarization experiments, coupons exposed to inhibited acidic solutions at pH 4 showed complete suppression of dissolution of Al2CuMg particles compared to zinc-free solutions in the SEM studies. Samples exposed in pH 4 Zn2+-bearing solution exhibited highest polarization resistance which was also observed to increase with time. In deaerated solutions, the inhibition by Zn2+ at pH 4 is not observed as strongly. The ability to make the interfacial electrolyte

  6. Intraperitoneal injection of d-serine inhibits high-fat diet intake and preference in male mice.

    Science.gov (United States)

    Sasaki, Tsutomu; Yasoshima, Yasunobu; Matsui, Sho; Yokota-Hashimoto, Hiromi; Kobayashi, Masaki; Kitamura, Tadahiro

    2017-11-01

    d-serine is a co-agonist of the N-methyl d-aspartate (NMDA) receptor, an important modulator of glutamatergic excitatory synaptic transmission. We previously reported that oral d-serine ingestion inhibited the intake of highly preferred food and promoted the intake of less preferred food in mice. Here, we analyzed the effects of intraperitoneal (IP) d-serine injections on feeding behavior in mice. We assessed the effects of d-serine during both the acquisition and maintenance of a preference for high-fat diets (HFDs). Aversiveness of IP d-serine was analyzed in the conditioned taste aversion paradigm. The effects on food intake were assessed by providing liquid meals with different fat contents. Finally, we measured brain d-serine and l-serine levels after d-serine administration. We found that IP-injected d-serine effectively inhibited the acquisition of a HFD preference, but failed to prevent expression of a previously learned HFD preference. IP-injected d-serine was not sufficient to condition taste aversion. The effect on HFD preference acquisition was associated with increases in d-serine levels in the cerebral cortex, hypothalamus, and cerebellum. IP-injected d-serine most effectively inhibited the intake of liquid meals with high fat content. This effect was dose-dependent, but the responses varied significantly among male C57BL/6J mice. The differential responses to d-serine were consistent among multiple trials in each mouse. In summary, IP-injected d-serine inhibited HFD intake and the acquisition of an HFD preference. Individual mice with the same genetic background showed different sensitivities to d-serine; thus, d-serine sensitivity may be associated with unidentified traits. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Specific inhibiting effects of Ilexonin A on von Willebrand factor-dependent platelet aggregation under high shear rate

    Institute of Scientific and Technical Information of China (English)

    李敏; 吴伟康; 刘良; 廖福龙; 篠原幸人; 半田俊之介; 後藤信哉

    2004-01-01

    Background Ilexonin A (IA), purified from the Chinese herbal medicine Maodongqing (Ilex pubescens Hook, et Am) has been commonly used in south China to treat thrombotic disorders. In this study, we aimed to study the inhibiting effects and mechanism of lA on von Willebrand factor (vWF)-dependent high shear-induced platelet aggregation. Methods vWF-dependent high shear (10 800 s-1) induced aggregation of platelets obtained from normal donors in the presence or absence of lA was measured by a modified cone-plate viscometer and shear-induced vWF binding was measured by quantitative flowcytometry with monoclonal antibody known to bind exclusively to the C-terminal domain of vWF (LJ-C3) directly labeled with fluorescein isothiocyanate (FITC). P-selectin surface expression was also measured by a similar method with FITC conjugated anti-P-selectin monoclonal antibody (WGA1).Results Shear-induced platelet aggregation was inhibited by IA in a dose-dependent manner. The extent of aggregation decreased from (78.6±4.6)% in the absence of lA to (36.5±2.1 )% in the presence of lA (3.3 mmol/L) (P<0.0001, n=9) with a high shear rate of 10800 s-1. vWF binding and P-selectin expression were also inhibited by lA in a dose dependent manner. The number of binding FITC-LJ-C3 molecules increased after exposure of platelet-rich plasma to a high shear rate of 10 800 s-1 for 6 minutes, but this shear-induced increased binding platelet surface vWF molecules and P-selectin expression can be decreased in the presence of IA.Conclusion vWF binding and vWF mediated platelet activation, aggregation occurring under high shear rate were inhibited by IA. lA may be a unique antithrombotic drug inhibiting the vWF-GP Ib α interaction, and may thus facilitate drug design targeting arterial thrombosis.

  8. High-mobility group box 1 inhibits HCO3- absorption in the medullary thick ascending limb through RAGE-Rho-ROCK-mediated inhibition of basolateral Na+/H+ exchange.

    Science.gov (United States)

    Watts, Bruns A; George, Thampi; Badalamenti, Andrew; Good, David W

    2016-09-01

    High-mobility group box 1 (HMGB1) is a nuclear protein released extracellularly in response to infection or injury, where it activates immune responses and contributes to the pathogenesis of kidney dysfunction in sepsis and sterile inflammatory disorders. Recently, we demonstrated that HMGB1 inhibits HCO3 (-) absorption in perfused rat medullary thick ascending limbs (MTAL) through a basolateral receptor for advanced glycation end products (RAGE)-dependent pathway that is additive to Toll-like receptor 4 (TLR4)-ERK-mediated inhibition by LPS (Good DW, George T, Watts BA III. Am J Physiol Renal Physiol 309: F720-F730, 2015). Here, we examined signaling and transport mechanisms that mediate inhibition by HMGB1. Inhibition of HCO3 (-) absorption by HMGB1 was eliminated by the Rho-associated kinase (ROCK) inhibitor Y27632 and by a specific inhibitor of Rho, the major upstream activator of ROCK. HMGB1 increased RhoA and ROCK1 activity. HMGB1-induced ROCK1 activation was eliminated by the RAGE antagonist FPS-ZM1 and by inhibition of Rho. The Rho and ROCK inhibitors had no effect on inhibition of HCO3 (-) absorption by bath LPS. Inhibition of HCO3 (-) absorption by HMGB1 was eliminated by bath amiloride, 0 Na(+) bath, and the F-actin stabilizer jasplakinolide, three conditions that selectively prevent inhibition of MTAL HCO3 (-) absorption mediated through NHE1. HMGB1 decreased basolateral Na(+)/H(+) exchange activity through activation of ROCK. We conclude that HMGB1 inhibits HCO3 (-) absorption in the MTAL through a RAGE-RhoA-ROCK1 signaling pathway coupled to inhibition of NHE1. The HMGB1-RAGE-RhoA-ROCK1 pathway thus represents a potential target to attenuate MTAL dysfunction during sepsis and other inflammatory disorders. HMGB1 and LPS inhibit HCO3 (-) absorption through different receptor signaling and transport mechanisms, which enables these pathogenic mediators to act directly and independently to impair MTAL function.

  9. Nicotinamide inhibits vasculogenic mimicry, an alternative vascularization pathway observed in highly aggressive melanoma.

    Directory of Open Access Journals (Sweden)

    Orit Itzhaki

    Full Text Available Vasculogenic mimicry (VM describes functional vascular channels composed only of tumor cells and its presence predicts poor prognosis in melanoma patients. Inhibition of this alternative vascularization pathway might be of clinical importance, especially as several anti-angiogenic therapies targeting endothelial cells are largely ineffective in melanoma. We show the presence of VM structures histologically in a series of human melanoma lesions and demonstrate that cell cultures derived from these lesions form tubes in 3D cultures ex vivo. We tested the ability of nicotinamide, the amide form of vitamin B3 (niacin, which acts as an epigenetic gene regulator through unique cellular pathways, to modify VM. Nicotinamide effectively inhibited the formation of VM structures and destroyed already formed ones, in a dose-dependent manner. Remarkably, VM formation capacity remained suppressed even one month after the complete withdrawal of Nicotimamid. The inhibitory effect of nicotinamide on VM formation could be at least partially explained by a nicotinamide-driven downregulation of vascular endothelial cadherin (VE-Cadherin, which is known to have a central role in VM. Further major changes in the expression profile of hundreds of genes, most of them clustered in biologically-relevant clusters, were observed. In addition, nicotinamide significantly inhibited melanoma cell proliferation, but had an opposite effect on their invasion capacity. Cell cycle analysis indicated moderate changes in apoptotic indices. Therefore, nicotinamide could be further used to unravel new biological mechanisms that drive VM and tumor progression. Targeting VM, especially in combination with anti-angiogenic strategies, is expected to be synergistic and might yield substantial anti neoplastic effects in a variety of malignancies.

  10. 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

  11. Study of the stenosis-inhibiting effects of high-dose rate endovascular irradiation in balloon injured rabbit iliac artery

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Masao; Sekine, Hiroshi; Suzuki, Akihiko; Ohyama, Noriaki; Hataba, Yoshiaki [Jikei Univ., Tokyo (Japan). School of Medicine

    2002-12-01

    With scanning electron microscopy, we investigated the effectiveness of inhibition by endovascular irradiation (Ir-192 high dose rate) of intimal hyperplasia after angioplasty. We also examined changes in the irradiated arterial vessel wall after balloon injury and the mechanism of the inhibition of intimal hyperplasia. Japanese white rabbits (male, 3.0-3.5 kg) were used. Under anesthesia, a percutaneous transluminal angioplasty balloon catheter was inserted into the iliac arteries and inflated to 6 atm for 1 minute 3 times at 1-minute intervals. One artery was irradiated (12 Gy) with an iridium-192 high-dose rate endovascular irradiation device (the reference point was set at 2 mm to center; dose rate 18-48 Gy/min). From 2 days to 12 weeks after the procedure, fixation was performed at a perfusion pressure of 120 to 150 cm H{sub 2}O, and the arteries were systematically examined. Endothelial cells after balloon injury with or without irradiation were examined with light microscopy or scanning electron microscopy. Endovascular irradiation inhibited intimal hyperplasia for at least 12 weeks. Irradiated arteries were not constricted, so we assumed that this phenomenon was caused by inhibition of negative remodeling. From 1 to 2 weeks after the procedure, we recognized mild intimal hyperplasia at nonirradiated arteries, but no hyperplasia recognized at irradiated arteries. This hyperplasia was mainly constituted by endothelial cells, and this change happened at least 2 days with scanning electron scopy. At the injury site, platelet aggregation, thrombus, and endothelial cells were observed. After irradiation, endothelial cells and nuclei were injured. Hypertrophic nuclei, the deformity of cell alignment, and stratified endothelial cells were recognized. It means that irradiation may affect the metabolism of the endothelial cells against normal formation with light microscopy. (author)

  12. Calcium phosphate coating containing silver shows high antibacterial activity and low cytotoxicity and inhibits bacterial adhesion

    Energy Technology Data Exchange (ETDEWEB)

    Ando, Yoshiki, E-mail: andoy@jmmc.jp [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Research Department, Japan Medical Materials Corporation, Uemura Nissei Bldg.9F 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003 (Japan); Miyamoto, Hiroshi [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Noda, Iwao; Sakurai, Nobuko [Research Department, Japan Medical Materials Corporation, Uemura Nissei Bldg.9F 3-3-31 Miyahara, Yodogawa-ku, Osaka 532-0003 (Japan); Akiyama, Tomonori [Division of Microbiology, Department of Pathology and Microbiology, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan); Yonekura, Yutaka; Shimazaki, Takafumi; Miyazaki, Masaki; Mawatari, Masaaki; Hotokebuchi, Takao [Department of Orthopaedic Surgery, Faculty of Medicine, Saga University, 5-1-1 Nabeshima, Saga 849-8501 (Japan)

    2010-01-01

    Surgical site infection is one of the serious complications of orthopedic implants. In order to reduce the incidence of implant-associated infections, we developed a novel coating technology of calcium phosphate (CP) containing silver (Ag), designated Ag-CP coating, using a thermal spraying technique. In this study, we evaluated the antibacterial efficacy and biological safety of this coating. In vitro antibacterial activity tests showed that the growths of Escherichia coli, Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) are completely suppressed on Ag-CP coating. In vitro bacterial adherence tests revealed that the number of adherent bacteria on the surface of this coating is significantly less (p < 0.02) than that on the surface of the CP coating. Moreover, the Ag-CP coating completely inhibits MRSA adhesion [<10 colony-forming units (CFU)] when 10{sup 2} CFU MRSA is inoculated. On the other hand, V79 Chinese hamster lung cells were found to grow on the Ag-CP coating as well as on the CP coating in a cytotoxicity test. These results indicate that the Ag-CP coating on the surface of orthopedic implants exhibits antibacterial activity and inhibits bacterial adhesion without cytotoxicity.

  13. Inorganic Corrosion-Inhibitive Pigments for High-Temperature Alkali-activated Well Casing Foam Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pyatina, T. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-11-01

    This study evaluates inorganic pigments for improving carbon steel (CS) brine-corrosion protection by the sodium metasilicate-activated calcium aluminate cement/Fly Ash blend at 300°C. Calcium borosilicate (CBS) and zinc phosphate, significantly improved CS corrosion-protection by decreasing cement’s permeability for corrosive ions and inhibiting anodic corrosion. An amorphous Na2O-Al2O3-SiO2-H2O phase tightly attached to CS surface formed at 300oC in CBS-modified cement pore solution. The corrosion rate of the CS covered with this phase was nearly 4-fold lower than in the case of nonmodified cement pore solution where the major phase formed on the surface of CS was crystalline analcime.

  14. Inorganic Corrosion-Inhibitive Pigments for High-Temperature Alkali-activated Well Casing Foam Cement

    Energy Technology Data Exchange (ETDEWEB)

    Sugama, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Pyatina, T. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2014-11-14

    This study evaluates inorganic pigments for improving carbon steel (CS) brine-corrosion protection by the sodium metasilicate-activated calcium aluminate cement/Fly Ash blend at 300°C. Calcium borosilicate (CBS) and zinc phosphate, significantly improved CS corrosion-protection by decreasing cement’s permeability for corrosive ions and inhibiting anodic corrosion. An amorphous Na2O-Al2O3-SiO2-H2O phase tightly attached to CS surface formed at 300oC in CBS-modified cement pore solution. The corrosion rate of the CS covered with this phase was nearly 4-fold lower than in the case of nonmodified cement pore solution where the major phase formed on the surface of CS was crystalline analcime.

  15. Glucose-Induced Oxidative Stress Reduces Proliferation in Embryonic Stem Cells via FOXO3A/β-Catenin-Dependent Transcription of p21cip1

    Directory of Open Access Journals (Sweden)

    Darcie L. McClelland Descalzo

    2016-07-01

    Full Text Available Embryonic stem cells (ESCs, which are derived from a peri-implantation embryo, are routinely cultured in medium containing diabetic glucose (Glc concentrations. While pregnancy in women with pre-existing diabetes may result in small embryos, whether such high Glc levels affect ESC growth remains uncovered. We show here that long-term exposure of ESCs to diabetic Glc inhibits their proliferation, thereby mimicking in vivo findings. Molecularly, Glc exposure increased oxidative stress and activated Forkhead box O3a (FOXO3a, promoting increased expression and activity of the ROS-removal enzymes superoxide dismutase and catalase and the cell-cycle inhibitors p21cip1 and p27kip1. Diabetic Glc also promoted β-catenin nuclear localization and the formation of a complex with FOXO3a that localized to the promoters of Sod2, p21cip1, and potentially p27kip1. Our results demonstrate an adaptive response to increases in oxidative stress induced by diabetic Glc conditions that promote ROS removal, but also result in a decrease in proliferation.

  16. Glucose-Induced Oxidative Stress Reduces Proliferation in Embryonic Stem Cells via FOXO3A/β-Catenin-Dependent Transcription of p21(cip1).

    Science.gov (United States)

    McClelland Descalzo, Darcie L; Satoorian, Tiffany S; Walker, Lauren M; Sparks, Nicole R L; Pulyanina, Polina Y; Zur Nieden, Nicole I

    2016-07-12

    Embryonic stem cells (ESCs), which are derived from a peri-implantation embryo, are routinely cultured in medium containing diabetic glucose (Glc) concentrations. While pregnancy in women with pre-existing diabetes may result in small embryos, whether such high Glc levels affect ESC growth remains uncovered. We show here that long-term exposure of ESCs to diabetic Glc inhibits their proliferation, thereby mimicking in vivo findings. Molecularly, Glc exposure increased oxidative stress and activated Forkhead box O3a (FOXO3a), promoting increased expression and activity of the ROS-removal enzymes superoxide dismutase and catalase and the cell-cycle inhibitors p21(cip1) and p27(kip1). Diabetic Glc also promoted β-catenin nuclear localization and the formation of a complex with FOXO3a that localized to the promoters of Sod2, p21(cip1), and potentially p27(kip1). Our results demonstrate an adaptive response to increases in oxidative stress induced by diabetic Glc conditions that promote ROS removal, but also result in a decrease in proliferation.

  17. Inhibition of c-Abl kinase activity renders cancer cells highly sensitive to mitoxantrone.

    Directory of Open Access Journals (Sweden)

    Kemal Alpay

    Full Text Available Although c-Abl has increasingly emerged as a key player in the DNA damage response, its role in this context is far from clear. We studied the effect of inhibition of c-Abl kinase activity by imatinib with chemotherapy drugs and found a striking difference in cell survival after combined mitoxantrone (MX and imatinib treatment compared to a panel of other chemotherapy drugs. The combinatory treatment induced apoptosis in HeLa cells and other cancer cell lines but not in primary fibroblasts. The difference in MX and doxorubicin was related to significant augmentation of DNA damage. Transcriptionally active p53 accumulated in cells in which human papillomavirus E6 normally degrades p53. The combination treatment resulted in caspase activation and apoptosis, but this effect did not depend on either p53 or p73 activity. Despite increased p53 activity, the cells arrested in G2 phase became defective in this checkpoint, allowing cell cycle progression. The effect after MX treatment depended partially on c-Abl: Short interfering RNA knockdown of c-Abl rendered HeLa cells less sensitive to MX. The effect of imatinib was decreased by c-Abl siRNA suggesting a role for catalytically inactive c-Abl in the death cascade. These findings indicate that MX has a unique cytotoxic effect when the kinase activity of c-Abl is inhibited. The treatment results in increased DNA damage and c-Abl-dependent apoptosis, which may offer new possibilities for potentiation of cancer chemotherapy.

  18. Highly effective inhibition of biofilm formation by the first metagenome-derived AI-2 quenching enzyme

    Directory of Open Access Journals (Sweden)

    Nancy Weiland-Bräuer

    2016-07-01

    Full Text Available Bacterial cell-cell communication (quorum sensing, QS represents a fundamental process crucial for biofilm formation, pathogenicity, and virulence allowing coordinated, concerted actions of bacteria depending on their cell density. With the widespread appearance of antibiotic-resistance of biofilms, there is an increasing need for novel strategies to control harmful biofilms. One attractive and most likely effective approach is to target bacterial communication systems for novel drug design in biotechnological and medical applications. In this study, metagenomic large-insert libraries were constructed and screened for QS interfering activities (quorum quenching, QQ using recently established reporter strains. Overall, 142 out of 46,400 metagenomic clones were identified to interfere with acyl-homoserine lactones (AHLs, 13 with autoinducer-2 (AI-2. Five cosmid clones with highest simultaneous interfering activities were further analyzed and the respective open reading frames conferring QQ activities identified. Those showed homologies to bacterial oxidoreductases, proteases, amidases and aminotransferases. Evaluating the ability of the respective purified QQ-proteins to prevent biofilm formation of several model systems demonstrated highest inhibitory effects of QQ-2 using the crystal violet biofilm assay. This was confirmed by heterologous expression of the respective QQ proteins in Klebsiella oxytoca M5a1 and monitoring biofilm formation in a continuous flow cell system. Moreover, QQ-2 chemically immobilized to the glass surface of the flow cell effectively inhibited biofilm formation of K. oxytoca as well as clinical K. pneumoniae isolates derived from patients with urinary tract infections. Indications were obtained by molecular and biochemical characterizations that QQ-2 represents an oxidoreductase most likely reducing the signaling molecules AHL and AI-2 to QS-inactive hydroxy-derivatives. Overall, we propose that the identified novel QQ-2

  19. Highly Effective Inhibition of Biofilm Formation by the First Metagenome-Derived AI-2 Quenching Enzyme

    Science.gov (United States)

    Weiland-Bräuer, Nancy; Kisch, Martin J.; Pinnow, Nicole; Liese, Andreas; Schmitz, Ruth A.

    2016-01-01

    Bacterial cell–cell communication (quorum sensing, QS) represents a fundamental process crucial for biofilm formation, pathogenicity, and virulence allowing coordinated, concerted actions of bacteria depending on their cell density. With the widespread appearance of antibiotic-resistance of biofilms, there is an increasing need for novel strategies to control harmful biofilms. One attractive and most likely effective approach is to target bacterial communication systems for novel drug design in biotechnological and medical applications. In this study, metagenomic large-insert libraries were constructed and screened for QS interfering activities (quorum quenching, QQ) using recently established reporter strains. Overall, 142 out of 46,400 metagenomic clones were identified to interfere with acyl-homoserine lactones (AHLs), 13 with autoinducer-2 (AI-2). Five cosmid clones with highest simultaneous interfering activities were further analyzed and the respective open reading frames conferring QQ activities identified. Those showed homologies to bacterial oxidoreductases, proteases, amidases and aminotransferases. Evaluating the ability of the respective purified QQ-proteins to prevent biofilm formation of several model systems demonstrated highest inhibitory effects of QQ-2 using the crystal violet biofilm assay. This was confirmed by heterologous expression of the respective QQ proteins in Klebsiella oxytoca M5a1 and monitoring biofilm formation in a continuous flow cell system. Moreover, QQ-2 chemically immobilized to the glass surface of the flow cell effectively inhibited biofilm formation of K. oxytoca as well as clinical K. pneumoniae isolates derived from patients with urinary tract infections. Indications were obtained by molecular and biochemical characterizations that QQ-2 represents an oxidoreductase most likely reducing the signaling molecules AHL and AI-2 to QS-inactive hydroxy-derivatives. Overall, we propose that the identified novel QQ-2 protein

  20. Do high-nickel leaves shed by the nickel hyperaccumulator Alyssum murale inhibit seed germination of competing plants?

    Science.gov (United States)

    Zhang, Lan; Angle, J Scott; Chaney, Rufus L

    2007-01-01

    Elemental allelopathy suggests that nickel (Ni)-rich leaves shed by hyperaccumulators inhibit the germination and growth of nearby plant species. Here, the germination of eight herbaceous species following addition of Alyssum murale biomass or Ni(NO3)2, with the same Ni level added to soil, was assessed. The distribution of Ni in soil was tested by determining Ni phytoavailability and speciation over time. Phytoavailable Ni in soil amended with biomass declined rapidly over time due to Ni binding to iron (Fe)/manganese (Mn) oxides in the soil. No significant effects on seed germination were observed. Unlike the Ni complex in Alyssum biomass, more Ni remained soluble and phytoavailable in soil amended with Ni(NO3)2, thus significantly inhibiting seed germination. High-Ni leaves shed by hyperaccumulators did not appear to create a 'toxic zone' around the plants and inhibit germination or growth of competing plants. The lack of an allelopathic effect was probably related to low Ni availability.

  1. Antimigraine drug, zolmitriptan, inhibits high-voltage activated calcium currents in a population of acutely dissociated rat trigeminal sensory neurons

    Directory of Open Access Journals (Sweden)

    Matsuzawa Yoshiyasu

    2006-03-01

    Full Text Available Abstract Background Triptans, 5-HT1B/ID agonists, act on peripheral and/or central terminals of trigeminal ganglion neurons (TGNs and inhibit the release of neurotransmitters to second-order neurons, which is considered as one of key mechanisms for pain relief by triptans as antimigraine drugs. Although high-voltage activated (HVA Ca2+ channels contribute to the release of neurotransmitters from TGNs, electrical actions of triptans on the HVA Ca2+ channels are not yet documented. Results In the present study, actions of zolmitriptan, one of triptans, were examined on the HVA Ca2+ channels in acutely dissociated rat TGNs, by using whole-cell patch recording of Ba2+ currents (IBa passing through Ca2+ channels. Zolmitriptan (0.1–100 μM reduced the size of IBa in a concentration-dependent manner. This zolmitriptan-induced inhibitory action was blocked by GR127935, a 5-HT1B/1D antagonist, and by overnight pretreatment with pertussis toxin (PTX. P/Q-type Ca2+ channel blockers inhibited the inhibitory action of zolmitriptan on IBa, compared to N- and L-type blockers, and R-type blocker did, compared to L-type blocker, respectively (p 1B/1D receptor linked to Gi/o pathway. Conclusion It is concluded that this zolmitriptan inhibition of HVA Ca2+ channels may explain the reduction in the release of neurotransmitters including CGRP, possibly leading to antimigraine effects of zolmitriptan.

  2. Identification of novel compounds inhibiting chikungunya virus-induced cell death by high throughput screening of a kinase inhibitor library.

    Directory of Open Access Journals (Sweden)

    Deu John M Cruz

    Full Text Available Chikungunya virus (CHIKV is a mosquito-borne arthrogenic alphavirus that causes acute febrile illness in humans accompanied by joint pains and in many cases, persistent arthralgia lasting weeks to years. The re-emergence of CHIKV has resulted in numerous outbreaks in the eastern hemisphere, and threatens to expand in the foreseeable future. Unfortunately, no effective treatment is currently available. The present study reports the use of resazurin in a cell-based high-throughput assay, and an image-based high-content assay to identify and characterize inhibitors of CHIKV-infection in vitro. CHIKV is a highly cytopathic virus that rapidly kills infected cells. Thus, cell viability of HuH-7 cells infected with CHIKV in the presence of compounds was determined by measuring metabolic reduction of resazurin to identify inhibitors of CHIKV-associated cell death. A kinase inhibitor library of 4,000 compounds was screened against CHIKV infection of HuH-7 cells using the resazurin reduction assay, and the cell toxicity was also measured in non-infected cells. Seventy-two compounds showing ≥50% inhibition property against CHIKV at 10 µM were selected as primary hits. Four compounds having a benzofuran core scaffold (CND0335, CND0364, CND0366 and CND0415, one pyrrolopyridine (CND0545 and one thiazol-carboxamide (CND3514 inhibited CHIKV-associated cell death in a dose-dependent manner, with EC50 values between 2.2 µM and 7.1 µM. Based on image analysis, these 6 hit compounds did not inhibit CHIKV replication in the host cell. However, CHIKV-infected cells manifested less prominent apoptotic blebs typical of CHIKV cytopathic effect compared with the control infection. Moreover, treatment with these compounds reduced viral titers in the medium of CHIKV-infected cells by up to 100-fold. In conclusion, this cell-based high-throughput screening assay using resazurin, combined with the image-based high content assay approach identified compounds against

  3. 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

  4. Inhibition of ice crystallisation in highly viscous aqueous organic acid droplets

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2008-09-01

    Full Text Available Homogeneous nucleation of ice within aqueous solution droplets and their subsequent crystallisation is thought to play a significant role in upper tropospheric ice cloud formation. It is normally assumed that homogeneous nucleation will take place at a threshold supersaturation, irrespective of the identity of the solute, and that rapid growth of ice particles will follow immediately after nucleation. However, it is shown here through laboratory experiments that droplets may not readily freeze in the very cold tropical tropopause layer (TTL, typical temperatures of 186–200 K. In these experiments ice crystal growth in citric acid solution droplets did not occur when ice nucleated below 197±6 K. Citric acid, 2-hydroxypropane-1,2,3-tricarboxyllic acid, is a molecule with similar functionality to oxygenated organic compounds which are ubiquitous in atmospheric aerosol. It is therefore thought to be a sensible proxy for atmospheric organic material. Evidence is presented that suggests citric acid solution droplets become ultra-viscous and form glassy solids under atmospherically relevant conditions. Diffusion of liquid water molecules to ice nuclei is expected to be very slow in ultra-viscous solution droplets and nucleation is negligible in glassy droplets; this most likely provides an explanation for the experimentally observed inhibition of ice crystallisation. The implications of ultra-viscous and glassy solution droplets for ice cloud formation and supersaturations in the TTL are discussed.

  5. Proanthocyanidins Inhibit Seed Germination by Maintaining a High Level of Abscisic Acid in Arabidopsis thaliana

    Institute of Scientific and Technical Information of China (English)

    Liguo Jia; Jianhua Zhang; Qiuyu Wu; Nenghui Ye; Rui Liu; Lu Shi; Weifeng Xu; Hui Zhi; A. N. M. Rubaiyath Bin Rahman; Yiji Xia

    2012-01-01

    Proanthocyanidins (PAs) are the main products of the flavonoid biosynthetic pathway in seeds,but their biological function during seed germination is still unclear.We observed that seed germination is delayed with the increase of exogenous PA concentration in Arabidopsis.A similar inhibitory effect occurred in peeled Brassica napus seeds,which was observed by measuring radicle elongation.Using abscisic acid (ABA),a biosynthetic and metabolic inhibitor,and gene expression analysis by real-time polymerase chain reaction,we found that the inhibitory effect of PAs on seed germination is due to their promotion of ABA via de novo biogenesis,rather than by any inhibition of its degradation.Consistent with the relationship between PA content and ABA accumulation in seeds,PA-deficient mutants maintain a lower level of ABA compared with wild-types during germination.Our data suggest that PA distribution in the seed coat can act as a doorkeeper to seed germination.PA regulation of seed germination is mediated by the ABA signaling pathway.

  6. Simultaneous high-speed imaging and optogenetic inhibition in the intact mouse brain

    Science.gov (United States)

    Bovetti, Serena; Moretti, Claudio; Zucca, Stefano; Dal Maschio, Marco; Bonifazi, Paolo; Fellin, Tommaso

    2017-01-01

    Genetically encoded calcium indicators and optogenetic actuators can report and manipulate the activity of specific neuronal populations. However, applying imaging and optogenetics simultaneously has been difficult to establish in the mammalian brain, even though combining the techniques would provide a powerful approach to reveal the functional organization of neural circuits. Here, we developed a technique based on patterned two-photon illumination to allow fast scanless imaging of GCaMP6 signals in the intact mouse brain at the same time as single-photon optogenetic inhibition with Archaerhodopsin. Using combined imaging and electrophysiological recording, we demonstrate that single and short bursts of action potentials in pyramidal neurons can be detected in the scanless modality at acquisition frequencies up to 1 kHz. Moreover, we demonstrate that our system strongly reduces the artifacts in the fluorescence detection that are induced by single-photon optogenetic illumination. Finally, we validated our technique investigating the role of parvalbumin-positive (PV) interneurons in the control of spontaneous cortical dynamics. Monitoring the activity of cellular populations on a precise spatiotemporal scale while manipulating neuronal activity with optogenetics provides a powerful tool to causally elucidate the cellular mechanisms underlying circuit function in the intact mammalian brain. PMID:28053310

  7. Simultaneous high-speed imaging and optogenetic inhibition in the intact mouse brain

    Science.gov (United States)

    Bovetti, Serena; Moretti, Claudio; Zucca, Stefano; Dal Maschio, Marco; Bonifazi, Paolo; Fellin, Tommaso

    2017-01-01

    Genetically encoded calcium indicators and optogenetic actuators can report and manipulate the activity of specific neuronal populations. However, applying imaging and optogenetics simultaneously has been difficult to establish in the mammalian brain, even though combining the techniques would provide a powerful approach to reveal the functional organization of neural circuits. Here, we developed a technique based on patterned two-photon illumination to allow fast scanless imaging of GCaMP6 signals in the intact mouse brain at the same time as single-photon optogenetic inhibition with Archaerhodopsin. Using combined imaging and electrophysiological recording, we demonstrate that single and short bursts of action potentials in pyramidal neurons can be detected in the scanless modality at acquisition frequencies up to 1 kHz. Moreover, we demonstrate that our system strongly reduces the artifacts in the fluorescence detection that are induced by single-photon optogenetic illumination. Finally, we validated our technique investigating the role of parvalbumin-positive (PV) interneurons in the control of spontaneous cortical dynamics. Monitoring the activity of cellular populations on a precise spatiotemporal scale while manipulating neuronal activity with optogenetics provides a powerful tool to causally elucidate the cellular mechanisms underlying circuit function in the intact mammalian brain.

  8. Inhibition of ice crystallisation in highly viscous aqueous organic acid droplets

    Directory of Open Access Journals (Sweden)

    B. J. Murray

    2008-05-01

    Full Text Available Homogeneous nucleation of ice within aqueous solution droplets and their subsequent crystallisation is thought to play a significant role in upper tropospheric ice cloud formation. It is normally assumed that homogeneous nucleation will take place at a threshold supersaturation, irrespective of the identity of the solute, and that rapid growth of ice particles will follow immediately after nucleation. However, it is shown here through laboratory experiments that droplets may not readily freeze in the very cold tropical tropopause layer (TTL, typical temperatures of 186–200 K. In these experiments ice crystal growth in citric acid solution droplets did not occur when ice nucleated below 197±6 K. Citric acid, 2-hydroxypropane-1,2,3-tricarboxyllic acid, is a molecule with similar functionality to oxygenated organic compounds which are ubiquitous to atmospheric aerosol and is therefore thought to be a sensible proxy for atmospheric organic material. Evidence is presented that suggest citric acid solution droplets become ultra-viscous or perhaps even glassy under atmospherically relevant conditions. Diffusion of liquid water molecules to ice nuclei is expected to be very slow in ultra-viscous solution droplets and this most likely provides an explanation for the experimentally observed inhibition of ice crystallisation. The implications of ultra-viscous solution droplets for ice cloud formation and supersaturations in the TTL are discussed.

  9. Islet β-cell ghrelin signaling for inhibition of insulin secretion.

    Science.gov (United States)

    Dezaki, Katsuya; Yada, Toshihiko

    2012-01-01

    Ghrelin, an acylated 28-amino acid peptide, was isolated from the stomach, where circulating ghrelin is produced predominantly. In addition to its unique role in regulating growth-hormone release, mealtime hunger, lipid metabolism, and the cardiovascular system, ghrelin is involved in the regulation of glucose metabolism. Ghrelin is expressed in pancreatic islets and released into pancreatic microcirculations. Ghrelin inhibits insulin release in mice, rats, and humans. Pharmacological and genetic blockades of islet-derived ghrelin markedly augment glucose-induced insulin release. The signal transduction mechanisms of ghrelin in islet β-cells are very unique, being distinct from those utilized for growth-hormone release. Ghrelin attenuates the glucose-induced cAMP production and PKA activation, which drives activation of Kv channels and suppression of the glucose-induced [Ca(2+)](i) increase and insulin release in β-cells. Insulinostatic function of the ghrelin-GHS-R system in islets is a potential therapeutic target for type 2 diabetes. Copyright © 2012 Elsevier Inc. All rights reserved.

  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. Inflammation induces multinucleation of Microglia via PKC inhibition of cytokinesis, generating highly phagocytic multinucleated giant cells.

    Science.gov (United States)

    Hornik, Tamara C; Neniskyte, Urte; Brown, Guy C

    2014-03-01

    Microglia are brain macrophages, which can undergo multinucleation to give rise to multinucleated giant cells that accumulate with ageing and some brain pathologies. However, the origin, regulation and function of multinucleate microglia remain unclear. We found that inflammatory stimuli, including lipopolysaccharide, amyloid β, α-synuclein, tumour necrosis factor-α and interferon γ, but not interleukin-4, induced multinucleation of cultured microglia: primary rat cortical microglia and the murine microglial cell line BV-2. Inflammation-induced multinucleation was prevented by a protein kinase C (PKC) inhibitor Gö6976 (100 nM) and replicated by a PKC activator phorbol myristate acetate (160 nM). Multinucleation was reversible and not because of cell fusion or phagocytosis, but rather failure of cytokinesis. Time-lapse imaging revealed that some dividing cells failed to abscise, even after formation of long cytoplasmic bridges, followed by retraction of bridge and reversal of cleavage furrow to form multinucleate cells. Multinucleate microglia were larger and 2-4 fold more likely to phagocytose large beads and both dead and live PC12 cells. We conclude that multinucleate microglia are reversibly generated by inflammation via PKC inhibition of cytokinesis, and may have specialized functions/dysfunctions including the phagocytosis of other cells. Inflammation resulted in the accumulation of multiple nuclei per cell in cultured microglia. This multinucleation was reversible and due to a PKC-dependent block of the last step of cell division. Multinucleate microglia were larger and had a greater capacity to phagocytose other cells, suggesting they might remove neurons in the brain. © 2013 International Society for Neurochemistry.

  12. Pseudomonas strains naturally associated with potato plants produce volatiles with high potential for inhibition of Phytophthora infestans.

    Science.gov (United States)

    Hunziker, Lukas; Bönisch, Denise; Groenhagen, Ulrike; Bailly, Aurélien; Schulz, Stefan; Weisskopf, Laure

    2015-02-01

    Bacteria emit volatile organic compounds with a wide range of effects on bacteria, fungi, plants, and animals. The antifungal potential of bacterial volatiles has been investigated with a broad span of phytopathogenic organisms, yet the reaction of oomycetes to these volatile signals is largely unknown. For instance, the response of the late blight-causing agent and most devastating oomycete pathogen worldwide, Phytophthora infestans, to bacterial volatiles has not been assessed so far. In this work, we analyzed this response and compared it to that of selected fungal and bacterial potato pathogens, using newly isolated, potato-associated bacterial strains as volatile emitters. P. infestans was highly susceptible to bacterial volatiles, while fungal and bacterial pathogens were less sensitive. Cyanogenic Pseudomonas strains were the most active, leading to complete growth inhibition, yet noncyanogenic ones also produced antioomycete volatiles. Headspace analysis of the emitted volatiles revealed 1-undecene as a compound produced by strains inducing volatile-mediated P. infestans growth inhibition. Supplying pure 1-undecene to P. infestans significantly reduced mycelial growth, sporangium formation, germination, and zoospore release in a dose-dependent manner. This work demonstrates the high sensitivity of P. infestans to bacterial volatiles and opens new perspectives for sustainable control of this devastating pathogen.

  13. Catechins inhibit atherosclerosis in male rats on a high fat diet

    Directory of Open Access Journals (Sweden)

    Erna Susanti

    2015-12-01

    High fat diet increases eNOS expression, decreases PI3K expression, and increases p38 MAPK activity. Administration of catechin decreases eNOS expression, increases PI3K expression, and decreases p38 MAPK activity.

  14. Cadmium inhibits the induction of high-affinity nitrate uptake in maize (Zea mays L.) roots.

    Science.gov (United States)

    Rizzardo, Cecilia; Tomasi, Nicola; Monte, Rossella; Varanini, Zeno; Nocito, Fabio F; Cesco, Stefano; Pinton, Roberto

    2012-12-01

    Cadmium (Cd) detoxification involves glutathione and phytochelatins biosynthesis: the higher need of nitrogen should require increased nitrate (NO(3)(-)) uptake and metabolism. We investigated inducible high-affinity NO(3)(-) uptake across the plasma membrane (PM) in maize seedlings roots upon short exposure (10 min to 24 h) to low Cd concentrations (0, 1 or 10 μM): the activity and gene transcript abundance of high-affinity NO(3)(-) transporters, NO(3)(-) reductases and PM H(+)-ATPases were analyzed. Exposure to 1 mM NO(3)(-) led to a peak in high-affinity (0.2 mM) NO(3)(-) uptake rate (induction), which was markedly lowered in Cd-treated roots. Plasma membrane H(+)-ATPase activity was also strongly limited, while internal NO(3)(-) accumulation and NO(3)(-) reductase activity in extracts of Cd treated roots were only slightly lowered. Kinetics of high- and low-affinity NO(3)(-) uptake showed that Cd rapidly (10 min) blocked the inducible high-affinity transport system; the constitutive high-affinity transport system appeared not vulnerable to Cd and the low-affinity transport system appeared to be less affected and only after a prolonged exposure (12 h). Cd-treatment also modified transcript levels of genes encoding high-affinity NO(3)(-) transporters (ZmNTR2.1, ZmNRT2.2), PM H(+)-ATPases (ZmMHA3, ZmMHA4) and NO(3)(-) reductases (ZmNR1, ZmNADH:NR). Despite an expectable increase in NO(3)(-) demand, a negative effect of Cd on NO(3)(-) nutrition is reported. Cd effect results in alterations at the physiological and transcriptional levels of NO(3)(-) uptake from the external solution and it is particularly severe on the inducible high-affinity anion transport system. Furthermore, Cd would limit the capacity of the plant to respond to changes in NO(3) (-) availability.

  15. Simultaneous administration of high-dose atorvastatin and clopidogrel does not interfere with platelet inhibition during percutaneous coronary intervention

    Directory of Open Access Journals (Sweden)

    Kreutz RP

    2016-06-01

    Full Text Available Rolf P Kreutz,1,2 Jeffrey A Breall,1 Anjan Sinha,1 Elisabeth von der Lohe,1 Richard J Kovacs,1 David A Flockhart,2,† 1Krannert Institute of Cardiology, 2Division of Clinical Pharmacology, Indiana University School of Medicine, Indianapolis, IN, USA †David A Flockhart passed away on November 26, 2015 Background: Reloading with high-dose atorvastatin shortly before percutaneous coronary interventions (PCIs has been proposed as a strategy to reduce periprocedural myonecrosis. There has been a concern that statins that are metabolized by cytochrome P450 3A4 may interfere with clopidogrel metabolism at high doses. The impact of simultaneous administration of high doses of atorvastatin and clopidogrel on the efficacy of platelet inhibition has not been established. Methods: Subjects (n=60 were randomized to receive atorvastatin 80 mg together with clopidogrel 600 mg loading dose (n=28 versus clopidogrel 600 mg alone (n=32 at the time of PCI. Platelet aggregation was measured at baseline, 4 hours after clopidogrel loading dose, and 16–24 hours after clopidogrel loading dose by light transmittance aggregometry using adenosine diphosphate as agonist. Results: Platelet aggregation was similar at baseline in both the atorvastatin and the control groups (adenosine diphosphate 10 µM: 57%±19% vs 61%±21%; P=0.52. There was no significant difference in platelet aggregation between the atorvastatin and the control groups at 4 hours (37%±18% vs 39%±21%; P=0.72 and 16–24 hours post-clopidogrel loading dose (35%±17% vs 37%±18%; P=0.75. No significant difference in incidence of periprocedural myonecrosis was observed between the atorvastatin and control groups (odds ratio: 1.02; 95% confidence interval 0.37–2.8. Conclusion: High-dose atorvastatin given simultaneously with clopidogrel loading dose at the time of PCI does not significantly alter platelet inhibition by clopidogrel. Statin reloading with high doses of atorvastatin at the time of PCI

  16. High and low frequency transcutaneous electrical nerve stimulation inhibits nociceptive responses induced by CO2 laser stimulation in humans.

    Science.gov (United States)

    de Tommaso, Marina; Fiore, Pietro; Camporeale, Alfonso; Guido, Marco; Libro, Giuseppe; Losito, Luciana; Megna, Marisa; Puca, Francomichele; Megna, Gianfranco

    2003-05-15

    The aim of the study was to evaluate the effects of transcutaneous electric nerve stimulation (TENS) on CO(2) laser evoked potentials (LEPs) in 16 normal subjects. The volar side of the forearm was stimulated by 10 Hz TENS in eight subjects and by 100 Hz TENS in the remainder; the skin of the forearm was stimulated by CO(2) laser and the LEPs were recorded in basal conditions and soon after and 15 min after TENS. Both low and high frequency TENS significantly reduced the subjective rating of heat stimuli and the LEPs amplitude, although high frequency TENS appeared more efficacious. TENS seemed to exert a mild inhibition of the perception and processing of pain induced by laser Adelta fibres activation; the implications of these effects in the clinical employment of TENS remain to be clarified.

  17. Microstructure and ultrastructure of high-amylose rice resistant starch granules modified by antisense RNA inhibition of starch branching enzyme.

    Science.gov (United States)

    Wei, Cunxu; Qin, Fengling; Zhu, Lijia; Zhou, Weidong; Chen, Yifang; Wang, Youping; Gu, Minghong; Liu, Qiaoquan

    2010-01-27

    A high-amylose transgenic rice line (TRS) modified by antisense RNA inhibition of starch branching enzymes revealed a resistant starch-rich quality. Compound starch granules in whole grains of the regular rice cultivar Teqing (TQ) were readily split during fracturing, whereas the starch granules in TRS were structurally intact and showed large voluminous, non-angular rounded bodies and elongated, filamentous structures tolerant of fracturing. In isolated preparation, TQ starch granules broke up into separate polygonal granules, whereas TRS starch granules kept their intactness. TRS starch granules consisted of packed smaller subgranules, some of which located at the periphery of starch granules were fused to each other with adjacent ones forming a thick band or wall encircling the entire circumference of the granules. TQ starch granules had a high concentration of amylose in the concentric hilum, whereas TRS starch granules showed a relatively even distribution of amylose with intense amylose in both hilum and band.

  18. High dose zinc supplementation induces hippocampal zinc deficiency and memory impairment with inhibition of BDNF signaling.

    Directory of Open Access Journals (Sweden)

    Yang Yang

    Full Text Available Zinc ions highly concentrate in hippocampus and play a key role in modulating spatial learning and memory. At a time when dietary fortification and supplementation of zinc have increased the zinc consuming level especially in the youth, the toxicity of zinc overdose on brain function was underestimated. In the present study, weaning ICR mice were given water supplemented with 15 ppm Zn (low dose, 60 ppm Zn (high dose or normal lab water for 3 months, the behavior and brain zinc homeostasis were tested. Mice fed high dose of zinc showed hippocampus-dependent memory impairment. Unexpectedly, zinc deficiency, but not zinc overload was observed in hippocampus, especially in the mossy fiber-CA3 pyramid synapse. The expression levels of learning and memory related receptors and synaptic proteins such as NMDA-NR2A, NR2B, AMPA-GluR1, PSD-93 and PSD-95 were significantly decreased in hippocampus, with significant loss of dendritic spines. In keeping with these findings, high dose intake of zinc resulted in decreased hippocampal BDNF level and TrkB neurotrophic signaling. At last, increasing the brain zinc level directly by brain zinc injection induced BDNF expression, which was reversed by zinc chelating in vivo. These results indicate that zinc plays an important role in hippocampus-dependent learning and memory and BDNF expression, high dose supplementation of zinc induces specific zinc deficiency in hippocampus, which further impair learning and memory due to decreased availability of synaptic zinc and BDNF deficit.

  19. High dose zinc supplementation induces hippocampal zinc deficiency and memory impairment with inhibition of BDNF signaling.

    Science.gov (United States)

    Yang, Yang; Jing, Xiao-Peng; Zhang, Shou-Peng; Gu, Run-Xia; Tang, Fang-Xu; Wang, Xiu-Lian; Xiong, Yan; Qiu, Mei; Sun, Xu-Ying; Ke, Dan; Wang, Jian-Zhi; Liu, Rong

    2013-01-01

    Zinc ions highly concentrate in hippocampus and play a key role in modulating spatial learning and memory. At a time when dietary fortification and supplementation of zinc have increased the zinc consuming level especially in the youth, the toxicity of zinc overdose on brain function was underestimated. In the present study, weaning ICR mice were given water supplemented with 15 ppm Zn (low dose), 60 ppm Zn (high dose) or normal lab water for 3 months, the behavior and brain zinc homeostasis were tested. Mice fed high dose of zinc showed hippocampus-dependent memory impairment. Unexpectedly, zinc deficiency, but not zinc overload was observed in hippocampus, especially in the mossy fiber-CA3 pyramid synapse. The expression levels of learning and memory related receptors and synaptic proteins such as NMDA-NR2A, NR2B, AMPA-GluR1, PSD-93 and PSD-95 were significantly decreased in hippocampus, with significant loss of dendritic spines. In keeping with these findings, high dose intake of zinc resulted in decreased hippocampal BDNF level and TrkB neurotrophic signaling. At last, increasing the brain zinc level directly by brain zinc injection induced BDNF expression, which was reversed by zinc chelating in vivo. These results indicate that zinc plays an important role in hippocampus-dependent learning and memory and BDNF expression, high dose supplementation of zinc induces specific zinc deficiency in hippocampus, which further impair learning and memory due to decreased availability of synaptic zinc and BDNF deficit.

  20. 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.

  1. Mitochondrial Dysfunction Plus High-Sugar Diet Provokes a Metabolic Crisis That Inhibits Growth.

    Directory of Open Access Journals (Sweden)

    Esko Kemppainen

    Full Text Available The Drosophila mutant tko25t exhibits a deficiency of mitochondrial protein synthesis, leading to a global insufficiency of respiration and oxidative phosphorylation. This entrains an organismal phenotype of developmental delay and sensitivity to seizures induced by mechanical stress. We found that the mutant phenotype is exacerbated in a dose-dependent fashion by high dietary sugar levels. tko25t larvae were found to exhibit severe metabolic abnormalities that were further accentuated by high-sugar diet. These include elevated pyruvate and lactate, decreased ATP and NADPH. Dietary pyruvate or lactate supplementation phenocopied the effects of high sugar. Based on tissue-specific rescue, the crucial tissue in which this metabolic crisis initiates is the gut. It is accompanied by down-regulation of the apparatus of cytosolic protein synthesis and secretion at both the RNA and post-translational levels, including a novel regulation of S6 kinase at the protein level.

  2. Inhibition of glutamate dehydrogenase and insulin secretion by KHG26377 does not involve ADP-ribosylation by SIRT4 or deacetylation by SIRT3

    OpenAIRE

    Eun-A Kim

    2012-01-01

    We investigated the mechanisms involved in KHG26377 regulationof glutamate dehydrogenase (GDH) activity, focusing onthe roles of SIRT4 and SIRT3. Intraperitoneal injection of micewith KHG26377 reduced GDH activity with concomitant repressionof glucose-induced insulin secretion. Consistent withtheir known functions, SIRT4 ribosylated GDH and reduced itsactivity, and SIRT3 deacetylated GDH, increasing its activity.However, KHG26377 did not affect SIRT4-mediated ADP-ribosylation/inhibition or SI...

  3. Do High School Chemistry Examinations Inhibit Deeper Level Understanding of Dynamic Reversible Chemical Reactions?

    Science.gov (United States)

    Wheeldon, R.; Atkinson, R.; Dawes, A.; Levinson, R.

    2012-01-01

    Background and purpose: Chemistry examinations can favour the deployment of algorithmic procedures like Le Chatelier's Principle (LCP) rather than reasoning using chemical principles. This study investigated the explanatory resources which high school students use to answer equilibrium problems and whether the marks given for examination answers…

  4. 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...

  5. Investigation of Kinetic Hydrate Inhibition Using a High Pressure Micro Differential Scanning Calorimeter

    DEFF Research Database (Denmark)

    Daraboina, Nagu; Malmos, Christine; von Solms, Nicolas

    2013-01-01

    Methane hydrate formation and decomposition were investigated in the presence of the kinetic inhibitor (Luvicap EG) and synergist (polyethylene oxide; PEO) using a high pressure micro-differential scanning calorimeter (HP-μDSC) with both temperature ramping and isothermal temperature programs...

  6. Structural Basis for High-Affinity Peptide Inhibition of Human Pin1

    Science.gov (United States)

    Zhang, Yan; Daum, Sebastian; Wildemann, Dirk; Zhou, Xiao Zhen; Verdecia, Mark A.; Bowman, Marianne E.; Lücke, Christian; Hunter, Tony; Lu, Kun-Ping; Fischer, Gunter; Noel, Joseph P.

    2009-01-01

    Human Pin1 is a key regulator of cell-cycle progression and plays growth-promoting roles in human cancers. High-affinity inhibitors of Pin1 may provide a unique opportunity for disrupting oncogenic pathways. Here we report two high-resolution X-ray crystal structures of human Pin1 bound to non-natural peptide inhibitors. The structures of the bound high-affinity peptides identify a type-I β-turn conformation for Pin1 prolyl peptide isomerase domain–peptide binding and an extensive molecular interface for high-affinity recognition. Moreover, these structures suggest chemical elements that may further improve the affinity and pharmacological properties of future peptide-based Pin inhibitors. Finally, an intramolecular hydrogen bond observed in both peptide complexes mimics the cyclic conformation of FK506 and rapamycin. Both FK506 and rapamycin are clinically important inhibitors of other peptidyl-prolyl cis-trans isomerases. This comparative discovery suggests that a cyclic peptide polyketide bridge, like that found in FK506 and rapamycin or a similar linkage, may significantly improve the binding affinity of structure-based Pin1 inhibitors. PMID:17518432

  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. Mitochondrial dysfunction plus high-sugar diet provokes a metabolic crisis that inhibits growth

    OpenAIRE

    Dunn, Cory David; Kemppainen, Esko; George, Jack; Garipler, Görkem; Tuomela, Tea ; Kiviranta, Essi; Soga, Tomoyoshi; Jacobs, Howard T.

    2016-01-01

    The Drosophila mutant tko(25t) exhibits a deficiency ofmitochondrial protein synthesis, leading to a global insufficiency of respiration and oxidative phosphorylation. This entrains an organismal phenotype of developmental delay and sensitivity to seizures induced bymechanical stress. We found that the mutant phenotype is exacerbated in a dose-dependent fashion by high dietary sugar levels. tko(25t) larvae were found to exhibit severe metabolic abnormalities that were further accentuated by h...

  9. Antigen-Specific Inhibition of High-Avidity T Cell Target Lysis by Low-Avidity T Cells via Trogocytosis

    Directory of Open Access Journals (Sweden)

    Brile Chung

    2014-08-01

    Full Text Available Current vaccine conditions predominantly elicit low-avidity cytotoxic T lymphocytes (CTLs, which are non-tumor-cytolytic but indistinguishable by tetramer staining or enzyme-linked immunospot from high-avidity CTLs. Using CTL clones of high or low avidity for melanoma antigens, we show that low-avidity CTLs can inhibit tumor lysis by high-avidity CTLs in an antigen-specific manner. This phenomenon operates in vivo: high-avidity CTLs control tumor growth in animals but not in combination with low-avidity CTLs specific for the same antigen. The mechanism involves stripping of specific peptide-major histocompatibility complexes (pMHCs via trogocytosis by low-avidity melanoma-specific CTLs without degranulation, leading to insufficient levels of specific pMHC on target cell surface to trigger lysis by high-avidity CTLs. As such, peptide repertoire on the cell surface is dynamic and continually shaped by interactions with T cells. These results describe immune regulation by low-avidity T cells and have implications for vaccine design.

  10. Arctigenin Inhibits Adipogenesis by Inducing AMPK Activation and Reduces Weight Gain in High-Fat Diet-Induced Obese Mice.

    Science.gov (United States)

    Han, Yo-Han; Kee, Ji-Ye; Park, Jinbong; Kim, Hye-Lin; Jeong, Mi-Young; Kim, Dae-Seung; Jeon, Yong-Deok; Jung, Yunu; Youn, Dong-Hyun; Kang, JongWook; So, Hong-Seob; Park, Raekil; Lee, Jong-Hyun; Shin, Soyoung; Kim, Su-Jin; Um, Jae-Young; Hong, Seung-Heon

    2016-09-01

    Although arctigenin (ARC) has been reported to have some pharmacological effects such as anti-inflammation, anti-cancer, and antioxidant, there have been no reports on the anti-obesity effect of ARC. The aim of this study is to investigate whether ARC has an anti-obesity effect and mediates the AMP-activated protein kinase (AMPK) pathway. We investigated the anti-adipogenic effect of ARC using 3T3-L1 pre-adipocytes and human adipose tissue-derived mesenchymal stem cells (hAMSCs). In high-fat diet (HFD)-induced obese mice, whether ARC can inhibit weight gain was investigated. We found that ARC reduced weight gain, fat pad weight, and triglycerides in HFD-induced obese mice. ARC also inhibited the expression of peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα) in in vitro and in vivo. Furthermore, ARC induced the AMPK activation resulting in down-modulation of adipogenesis-related factors including PPARγ, C/EBPα, fatty acid synthase, adipocyte fatty acid-binding protein, and lipoprotein lipase. This study demonstrates that ARC can reduce key adipogenic factors by activating the AMPK in vitro and in vivo and suggests a therapeutic implication of ARC for obesity treatment. J. Cell. Biochem. 117: 2067-2077, 2016. © 2016 Wiley Periodicals, Inc.

  11. Dohaekseunggi-tang extract inhibits obesity, hyperlipidemia, and hypertension in high-fat diet-induced obese mice.

    Science.gov (United States)

    Sung, Yoon-Young; Kim, Dong-Seon; Choi, Goya; Kim, Seung-Hyung; Kim, Ho Kyoung

    2014-10-04

    Dohaekseunggi-tang (DHSGT) is a traditional plant-based medicine prescribed to promote blood circulation and to treat obesity and hypertension. The present study aimed to identify potential anti-obesity activities of DHSGT extract. Anti-obesity, anti-hyperlipidemic, and anti-hypertensive effects of orally-administered DHSGT extract were evaluated in high-fat diet- (HFD)-induced obese mice. Serum biochemistry profiles and expression of diverse metabolic regulatory gene mRNAs in mouse visceral fat were assessed by RT-PCR. The effects of DHSGT on angiotensin-1 converting enzyme (ACE) and pancreatic lipase activities were determined using in vitro inhibition assays. Oral DHSGT treatment reduced obese HFD C57BL/6 J mouse body weight, liver and adipose tissue mass, adipocyte size, and blood pressure versus untreated HFD mice. DHSGT also decreased serum total cholesterol, LDL-cholesterol, triglyceride, glucose, and leptin concentrations, and increased HDL-cholesterol and adiponectin levels in HFD mice. Furthermore, DHSGT markedly increased mRNA expression of peroxisome proliferator activated receptor-gamma, uncoupling protein-2, and adiponectin in visceral adipose tissue of HFD mice. In vitro tests revealed that DHSGT effectively inhibited porcine pancreatic lipase and ACE activities, with IC50 values of 7.58 mg/ml and 0.56 mg/ml, respectively. These results validate traditional knowledge and suggest that DHSGT may be potentially useful for managing hyperlipidemia, hyperglycemia, hypertension, and obesity.

  12. Ethyl pyruvate reduces myocardial ischemia and reperfusion injury by inhibiting high mobility group box 1 protein in rats.

    Science.gov (United States)

    Hu, Xiaorong; Cui, Bo; Zhou, Xiaoya; Xu, Changwu; Lu, Zhibing; Jiang, Hong

    2012-01-01

    High mobility group box 1 protein (HMGB1) plays an important role in myocardial ischemia and reperfusion (I/R) injury. Ethyl pyruvate (EP), a potent reactive oxygen species scavenger, has been reported to inhibit myocardial apoptosis and reduce myocardial I/R injury. The aim of this study was to investigate the mechanism by which EP reduces myocardial I/R injury in rats. Anesthetized male rats were once treated with EP (50 mg/kg, i.p.) before ischemia, and then subjected to ischemia for 30 min followed by reperfusion for 4 h. Lactate dehydrogenase (LDH), creatine kinase (CK), malondialdehyde (MDA), superoxide dismutase (SOD) activity and infarct size were measured. HMGB1 expression was assessed by immunoblotting. The results showed that pretreatment of EP (50 mg/kg) could significantly reduce the infarct size and the levels of LDH and CK after 4 h reperfusion (all PR. The present study suggested that ethyl pyruvate could attenuate myocardial I/R injury by inhibiting HMGB1 expression.

  13. Inhibition of high-mobility group box 1 expression by siRNA in rat hepatic stellate cells

    Institute of Scientific and Technical Information of China (English)

    Wen-Song Ge; Jian-Xin Wu; Jian-Gao Fan; Yao-Jun Wang; Ying-Wei Chen

    2011-01-01

    AIM: To explore the role of high-mobility group box 1 (HMGB1) protein during liver fibrogenesis and investigate the functional effects of HMGB1 gene silencing in hepatic stellate cells (HSCs) using siRNA. METHODS: Hepatic fibrosis in rats was induced through serial subcutaneous injections of dimethylnitrosamine, and expression of HMGB1 was detected by immunohistochemistry. HMGB1 siRNAs were developed and transiently transfected into HSC-T6 cells using Lipofectamine 2000. HMGB1 expression was evaluated by real-time polymerase chain reaction (PCR) and Western blotting analysis. Expression of α-smooth muscle actin (α-SMA) and collagen types Ⅰ and Ⅲ was evaluated by real-time PCR. Cell proliferation and the cell cycle were determined using the methyl thiazolyl tetrazolium method. Finally, collagen content in HSC supernatant was evaluated by an enzyme-linked immunosorbent assay. RESULTS: The results showed that HMGB1 was upregulated during liver fibrosis and that its expression was closely correlated with the deposition of collagen. siRNA molecules were successfully transfected into HSCs and induced inhibition of HMGB1 expression in a time-dependent manner. Moreover, HMGB1 siRNA treatment inhibited synthesis of α-SMA and collagen types Ⅰ and Ⅲ in transfected HSCs. CONCLUSION: This study suggests a significant functional role for HMGB1 in the development of liver fibrosis. It also demonstrates that downregulation of HMGB1 expression might be a potential strategy to treat liver fibrosis.

  14. Delayed hypersensitivity and migration inhibition in two lines of mice genetically selected for high or low responsiveness to phytohemagglutinin.

    Science.gov (United States)

    Gauthier-Rahman, S; El Rouby, S; Liacopoulos-Briot, M; Stiffel, C; Decreusefond, C; Liacopoulos, P

    1983-04-15

    Delayed-type hypersensitivity (DTH) and cell migration inhibition (MI) were studied in two lines of mice genetically selected for the high (Hi/PHA) or low (Lo/PHA) in vitro response of their lymphoid cells to phytochemagglutinin (PHA). A rapid photoelectric procedure for reading cell migrations enabled the study of MI over a wide range (10 log) of antigen concentrations in vitro. Hi/PHA mice required immunization with a 10 times higher dose of ovalbumin (OVA) in Freund's complete adjuvant (FCA) than Lo/PHA mice for a comparable response in DTH (footpad swelling) and MI of their induced peritoneal exudate cells (PEC). Lo/PHA spleen showed marked bizonal MI on Day 5 after immunization with low doses (0.1 and 0.5 micrograms) of OVA in FCA, one peak being obtained in presence of in vitro concentrations of 10(-3) or 10(-2) micrograms/ml OVA and another peak at 1 or 10 micrograms/ml, whereas Hi/PHA spleen showed stimulation of migration. In contrast, MI in Lo/PHA spleen failed to persist beyond Day 19, whereas it appeared progressively in Hi/PHA spleen, being maximal by Day 27. Low-zone inhibition in Hi/PHA spleen and PEC was lacking or poor even after immunization with higher doses of OVA in FCA. The implications of these findings are discussed.

  15. Activation of Plant Innate Immunity by Extracellular High Mobility Group Box 3 and Its Inhibition by Salicylic Acid.

    Directory of Open Access Journals (Sweden)

    Hyong Woo Choi

    2016-03-01

    Full Text Available Damage-associated molecular pattern molecules (DAMPs signal the presence of tissue damage to induce immune responses in plants and animals. Here, we report that High Mobility Group Box 3 (HMGB3 is a novel plant DAMP. Extracellular HMGB3, through receptor-like kinases BAK1 and BKK1, induced hallmark innate immune responses, including i MAPK activation, ii defense-related gene expression, iii callose deposition, and iv enhanced resistance to Botrytis cinerea. Infection by necrotrophic B. cinerea released HMGB3 into the extracellular space (apoplast. Silencing HMGBs enhanced susceptibility to B. cinerea, while HMGB3 injection into apoplast restored resistance. Like its human counterpart, HMGB3 binds salicylic acid (SA, which results in inhibition of its DAMP activity. An SA-binding site mutant of HMGB3 retained its DAMP activity, which was no longer inhibited by SA, consistent with its reduced SA-binding activity. These results provide cross-kingdom evidence that HMGB proteins function as DAMPs and that SA is their conserved inhibitor.

  16. Gentamicin rapidly inhibits mitochondrial metabolism in high-frequency cochlear outer hair cells.

    Directory of Open Access Journals (Sweden)

    Heather C Jensen-Smith

    Full Text Available Aminoglycosides (AG, including gentamicin (GM, are the most frequently used antibiotics in the world and are proposed to cause irreversible cochlear damage and hearing loss (HL in 1/4 of the patients receiving these life-saving drugs. Akin to the results of AG ototoxicity studies, high-frequency, basal turn outer hair cells (OHCs preferentially succumb to multiple HL pathologies while inner hair cells (IHCs are much more resilient. To determine if endogenous differences in IHC and OHC mitochondrial metabolism dictate differential sensitivities to AG-induced HL, IHC- and OHC-specific changes in mitochondrial reduced nicotinamide adenine dinucleotide (NADH fluorescence during acute (1 h GM treatment were compared. GM-mediated decreases in NADH fluorescence and succinate dehydrogenase activity were observed shortly after GM application. High-frequency basal turn OHCs were found to be metabolically biased to rapidly respond to alterations in their microenvironment including GM and elevated glucose exposures. These metabolic biases may predispose high-frequency OHCs to preferentially produce cell-damaging reactive oxygen species during traumatic challenge. Noise-induced and age-related HL pathologies share key characteristics with AG ototoxicity, including preferential OHC loss and reactive oxygen species production. Data from this report highlight the need to address the role of mitochondrial metabolism in regulating AG ototoxicity and the need to illuminate how fundamental differences in IHC and OHC metabolism may dictate differences in HC fate during multiple HL pathologies.

  17. High levels of jasmonic acid antagonize the biosynthesis of gibberellins and inhibit the growth of Nicotiana attenuata stems.

    Science.gov (United States)

    Heinrich, Maria; Hettenhausen, Christian; Lange, Theo; Wünsche, Hendrik; Fang, Jingjing; Baldwin, Ian T; Wu, Jianqiang

    2013-02-01

    Hormones play pivotal roles in regulating plant development, growth, and stress responses, and cross-talk among different hormones fine-tunes various aspects of plant physiology. Jasmonic acid (JA) is important for plant defense against herbivores and necrotic fungi and also regulates flower development; in addition, Arabidopsis mutants over-producing JA usually have stunted stems and wound-induced jasmonates suppress Arabidopsis growth, suggesting that JA is also involved in stem elongation. Gibberellins (GAs) promote stem and leaf growth and modulate seed germination, flowering time, and the development of flowers, fruits, and seeds. However, little is known about the interaction between the JA and GA pathways. Two calcium-dependent protein kinases, CDPK4 and CDPK5, are important suppressors of JA accumulation in a wild tobacco species, Nicotiana attenuata. The stems of N. attenuata silenced in CDPK4 and CDPK5 (irCDPK4/5 plants) had dramatically increased levels of JA and exhibited stunted elongation and had very high contents of secondary metabolites. Genetic analysis indicated that the high JA levels in irCDPK4/5 stems accounted for the suppressed stem elongation and the accumulation of secondary metabolites. Supplementation of GA(3) to irCDPK4/5 plants largely restored normal stem growth to wild-type levels. Measures of GA levels indicated that over-accumulation of JA in irCDPK4/5 stems inhibited the biosynthesis of GAs. Finally, we show that JA antagonizes GA biosynthesis by strongly inhibiting the transcript accumulation of GA20ox and possibly GA13ox, the key genes in GA production, demonstrating that high JA levels antagonize GA biosynthesis in stems.

  18. Geraniol improves endothelial function by inhibiting NOX-2 derived oxidative stress in high fat diet fed mice

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xiaoyu; Zhao, Shiqi; Su, Mengqi; Sun, Li; Zhang, Song; Wang, Dingyu; Liu, Zhaorui; Yuan, Yue; Liu, Yang [Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, Heilongjiang Province (China); Li, Yue, E-mail: ly99ly@vip.163.com [Department of Cardiology, the First Affiliated Hospital, Harbin Medical University, Harbin 150001, Heilongjiang Province (China); Key Laboratory of Cardiac Diseases and Heart Failure, Harbin Medical University, Harbin, 150001, Heilongjiang Province (China)

    2016-05-20

    Endothelial dysfunction occurs in obese patients and high-fat diet (HFD) fed experimental animals. While geraniol has been reported to ameliorate inflammation and oxidative stress, inhibit tumor cell proliferation, and improve atherosclerosis, its direct effect on endothelial function remains uncharacterized. The present study therefore investigated the effect of geraniol on endothelial function in HFD mice and its underlying mechanisms. C57 BL/6 mice were fed an HFD (n = 40) or a normal diet (n = 20) for 8 weeks. HFD fed mice then were randomized to intraperitoneal treatment with geraniol (n = 20) or vehicle (n = 20) for another 6 weeks. Acetylcholine (Ach)-induced endothelial dependent vasorelaxation was measured on wire myography; reactive oxygen species (ROS) generation was assessed by fluorescence imaging, and NADPH oxidases (NOXs) and adhesive molecules VCAM-1 and ICAM-1 protein expression by western blotting. Geraniol improved endothelial function in HFD fed mice, as evidenced by its: 1. restoring endothelial dependent vasorelaxation induced by Ach, and reversing increased VCAM-1 and ICAM-1 expression; 2. attenuating HFD induced increased serum TBARS and aortic ROS generation; and 3. downregulating aortic NOX-2 expression in both HFD fed mice and in palmitic acid treated endothelial cells. Geraniol therefore protects against endothelial dysfunction induced by HFD through reducing NOX-2 associated ROS generation. -- Highlights: •Geraniol improved endothelial dependent relaxation in high fat diet fed mice. •Geraniol alleviated vascular injury in high fat diet fed mice. •Geraniol inhibited ROS generation through downregulating NOX-2 expression.

  19. High-power helium-neon laser irradiation inhibits the growth of traumatic scars in vitro and in vivo.

    Science.gov (United States)

    Shu, Bin; Ni, Guo-Xin; Zhang, Lian-Yang; Li, Xiang-Ping; Jiang, Wan-Ling; Zhang, Li-Qun

    2013-05-01

    This study explored the inhibitory effect of the high-power helium-neon (He-Ne) laser on the growth of scars post trauma. For the in vitro study, human wound fibroblasts were exposed to the high-power He-Ne laser for 30 min, once per day with different power densities (10, 50, 100, and 150 mW/cm(2)). After 3 days of repeated irradiation with the He-Ne laser, fibroblast proliferation and collagen synthesis were evaluated. For in vivo evaluation, a wounded animal model of hypertrophic scar formation was established. At postoperative day 21, the high-power He-Ne laser irradiation (output power 120 mW, 6 mm in diameter, 30 min each session, every other day) was performed on 20 scars. At postoperative day 35, the hydroxyproline content, apoptosis rate, PCNA protein expression and FADD mRNA level were assessed. The in vitro study showed that the irradiation group that received the power densities of 100 and 150 mW/cm(2) showed decreases in the cell proliferation index, increases in the percentage of cells in the G0/G1 phase, and decreases in collagen synthesis and type I procollagen gene expression. In the in vivo animal studies, regions exposed to He-Ne irradiation showed a significant decrease in scar thickness as well as decreases in hydroxyproline levels and PCNA protein expression. Results from the in vitro and in vivo studies suggest that repeated irradiation with a He-Ne laser at certain power densities inhibits fibroblast proliferation and collagen synthesis, thereby inhibits the growth of hypertrophic scars.

  20. Herb–drug interaction prediction based on the high specific inhibition of andrographolide derivatives towards UDP-glucuronosyltransferase (UGT) 2B7

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Hai-Ying, E-mail: cmu4h-mhy@126.com [The Fourth Affiliated Hospital of China Medical University, Shenyang 110032 (China); Sun, Dong-Xue [School of Traditional Chinese Medicine, Shenyang Pharmaceutical University, No. 103, Wenhua Road, Shenyang 110016 (China); Cao, Yun-Feng [The First Affiliated Hospital of Liaoning Medical University, Jinzhou 121001 (China); Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Ai, Chun-Zhi [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Qu, Yan-Qing [Thyroid Surgery, Yantaishan Hospital, Yantai, Shandong (China); Hu, Cui-Min [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC 20057 (United States); Jiang, Changtao [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892 (United States); Dong, Pei-Pei [Academy of Integrative Medicine, Dalian Medical University, Dalian 116044 (China); Sun, Xiao-Yu; Hong, Mo [Joint Center for Translational Medicine, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road, Dalian 116023 (China); Tanaka, Naoki; Gonzalez, Frank J. [Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892 (United States); and others

    2014-05-15

    Herb–drug interaction strongly limits the clinical application of herbs and drugs, and the inhibition of herbal components towards important drug-metabolizing enzymes (DMEs) has been regarded as one of the most important reasons. The present study aims to investigate the inhibition potential of andrographolide derivatives towards one of the most important phase II DMEs UDP-glucuronosyltransferases (UGTs). Recombinant UGT isoforms (except UGT1A4)-catalyzed 4-methylumbelliferone (4-MU) glucuronidation reaction and UGT1A4-catalyzed trifluoperazine (TFP) glucuronidation were employed to firstly screen the andrographolide derivatives' inhibition potential. High specific inhibition of andrographolide derivatives towards UGT2B7 was observed. The inhibition type and parameters (K{sub i}) were determined for the compounds exhibiting strong inhibition capability towards UGT2B7, and human liver microsome (HLMs)-catalyzed zidovudine (AZT) glucuronidation probe reaction was used to furtherly confirm the inhibition behavior. In combination of inhibition parameters (K{sub i}) and in vivo concentration of andrographolide and dehydroandrographolide, the potential in vivo inhibition magnitude was predicted. Additionally, both the in vitro inhibition data and computational modeling results provide important information for the modification of andrographolide derivatives as selective inhibitors of UGT2B7. Taken together, data obtained from the present study indicated the potential herb–drug interaction between Andrographis paniculata and the drugs mainly undergoing UGT2B7-catalyzed metabolic elimination, and the andrographolide derivatives as potential candidates for the selective inhibitors of UGT2B7. - Highlights: • Specific inhibition of andrographolide derivatives towards UGT2B7. • Herb-drug interaction related withAndrographis paniculata. • Guidance for design of UGT2B7 specific inhibitors.

  1. High Frequency Stimulation of the Pelvic Nerve Inhibits Urinary Voiding in Anesthetized Rats

    Directory of Open Access Journals (Sweden)

    Jonathan J. Crook

    2017-08-01

    Full Text Available Urge Urinary Incontinence: “a sudden and uncontrollable desire to void which is impossible to defer” is extremely common and considered the most bothersome of lower urinary tract conditions. Current treatments rely on pharmacological, neuromodulatory, and neurotoxicological approaches to manage the disorder, by reducing the excitability of the bladder muscle. However, some patients remain refractory to treatment. An alternative approach would be to temporarily suppress activity of the micturition control circuitry at the time of need i.e., urgency. In this study we investigated, in a rat model, the utility of high frequency pelvic nerve stimulation to produce a rapid onset, reversible suppression of voiding. In urethane-anesthetized rats periodic voiding was induced by continuous infusion of saline into the bladder whilst recording bladder pressure and electrical activity from the external urethral sphincter (EUS. High frequency (1–3 kHz, sinusoidal pelvic nerve stimulation initiated at the onset of the sharp rise in bladder pressure signaling an imminent void aborted the detrusor contraction. Urine output was suppressed and tone in the EUS increased. Stimulating the right or left nerve was equally effective. The effect was rapid in onset, reversible, and reproducible and evoked only minimal “off target” side effects on blood pressure, heart rate, respiration, uterine pressure, or rectal pressure. Transient contraction of abdominal wall was observed in some animals. Stimulation applied during the filling phase evoked a small, transient rise in bladder pressure and increased tonic activity in the EUS, but no urine output. Suppression of micturition persisted after section of the contralateral pelvic nerve or after ligation of the nerve distal to the electrode cuff on the ipsilateral side. We conclude that high frequency pelvic nerve stimulation initiated at the onset of an imminent void provides a potential means to control urinary

  2. High dose 1,25(OH)2D3 inhibits osteoblast mineralization in vitro.

    Science.gov (United States)

    Yamaguchi, Masayoshi; Weitzmann, M Neale

    2012-05-01

    Vitamin D is essential for optimal calcium absorption needed for maintaining normal bone mineral density (BMD). Consequently, vitamin D-deficiency leads to poorly mineralized bone with diminished strength and load bearing capacity. Surprisingly, several animal and clinical studies have identified suppressive effects of high dose vitamin D supplementation on bone formation. These data suggest that while vitamin D is necessary for basal bone homeostasis, excessive concentrations may be detrimental to the skeleton. To further examine the direct effects of high dose vitamin D on the function of osteoblasts we differentiated primary osteoblast precursors and MC3T3 preosteoblastic cells, in the presence of supraphysiological doses of the active metabolite, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3]. In vitro osteoblast mineralization was potently suppressed by high dose 1,25(OH)2D3. To investigate the mechanism we used a bioassay to examine nuclear factor-κB (NF-κB) activation in MC3T3 cells. Although NF-κB agonists are generally potent inhibitors of osteoblast differentiation, surprisingly, 1,25(OH)2D3 dose-dependently suppressed, rather than stimulated, NF-κB activation. Interestingly, 1,25(OH)2D3 also suppressed Smad activation induced by the osteoblast commitment and differentiation factors transforming growth factor-β (TGF-β) and bone morphogenetic protein 2 (BMP2), which may account for the inhibitory activities of 1,25(OH)2D3 on mineralization. Our data suggest that vitamin D has complex pleiotropic effects on osteoblast signal transduction. As the net balance of high dose 1,25(OH)2D3 appears to be an inhibitory action on osteoblasts, our data suggest that the therapeutic value of vitamin D to maximize bone mass through indirect actions on calcium absorption may need to be carefully balanced with potential inhibitory direct effects on mineralizing cells. Our data suggest that indiscriminate over-dosing may be detrimental to bone formation and optimal

  3. In vitro and in vivo inhibition of aldose reductase and advanced glycation end products by phloretin, epigallocatechin 3-gallate and [6]-gingerol.

    Science.gov (United States)

    Sampath, Chethan; Sang, Shengmin; Ahmedna, Mohamed

    2016-12-01

    Hyperglycemic stress activates polyol pathway and aldose reductase (AR) key enzyme responsible for generating secondary complications during diabetes. In this study the therapeutic potential of phloretin, epigallocatechin 3-gallate (EGCG) and [6]-gingerol were evaluated for anti-glycating and AR inhibitory activity in vitro and in vivo systems. Human retinal pigment epithelial (HRPE) cells were induced with high glucose supplemented with the phloretin, EGCG and [6]-gingerol. Aldose reductase activity, total advanced glycation end products (AGEs) and enzyme inhibitor kinetics were assessed. Male C57BL/6J mice were randomly assigned to one of the different treatments (bioactive compounds at 2 concentrations each) with either a low fat diet or high fat diet (HFD). After sixteen weeks, AGE accumulation and AR activity was determined in heart, eyes and kidney. High glucose induced toxicity decreased cell viability compared to the untreated cells and AR activity increased to 2-5 folds from 24 to 96h. Pre-treatment of cells with phloretin, EGCG and [6]-gingerol improved cell viability and inhibited AR activity. The enzyme inhibition kinetics followed a non-competitive mode of inhibition for phloretin and EGCG whereas [6]-gingerol indicated uncompetitive type of inhibition against AR. Data from the animal studies showed high plasma glucose levels in HFD group over time, compared to the low fat diet. HFD group developed cataract and AR activity increased to 4 folds compared to the group with low fat diet. Administration of EGCG, phloretin and [6]-gingerol significantly reduced blood sugar levels, AGEs accumulation, and AR activity. These findings could provide a basis to consider using the selected dietary components alone or in combination with other therapeutic approaches to prevent diabetes-related complications in humans. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  4. The ryanodine receptor pore blocker neomycin also inhibits channel activity via a previously undescribed high-affinity Ca(2+) binding site.

    Science.gov (United States)

    Laver, Derek R; Hamada, Tomoyo; Fessenden, James D; Ikemoto, Noriaki

    2007-12-01

    In this study, we present evidence for the mechanism of neomycin inhibition of skeletal ryanodine receptors (RyRs). In single-channel recordings, neomycin produced monophasic inhibition of RyR open probability and biphasic inhibition of [(3)H]ryanodine binding. The half-maximal inhibitory concentration (IC(50)) for channel blockade by neomycin was dependent on membrane potential and cytoplasmic [Ca(2+)], suggesting that neomycin acts both as a pore plug and as a competitive antagonist at a cytoplasmic Ca(2+) binding site that causes allosteric inhibition. This novel Ca(2+)/neomycin binding site had a neomycin affinity of 100 nM: and a Ca(2+) affinity of 35 nM,: which is 30-fold higher than that of the well-described cytoplasmic Ca(2+) activation site. Therefore, a new high-affinity class of Ca(2+) binding site(s) on the RyR exists that mediates neomycin inhibition. Neomycin plugging of the channel pore induced brief (1-2 ms) conductance substates at 30% of the fully open conductance, whereas allosteric inhibition caused complete channel closure with durations that depended on the neomycin concentration. We quantitatively account for these results using a dual inhibition model for neomycin that incorporates voltage-dependent pore plugging and Ca(2+)-dependent allosteric inhibition.

  5. High dietary sodium blunts affects of angiotensin-converting enzyme inhibition on vascular angiotensin I-to-angiotensin II conversion in rats

    NARCIS (Netherlands)

    Kocks, Menno J A; Buikema, Hendrik; Gschwend, Simone; Boomsma, Frans; de Zeeuw, Dick; Navis, Gerjan

    2003-01-01

    High sodium intake blunts the efficacy of angiotensin (Ang)-converting enzyme (ACE) inhibition (ACEi), but the underlying mechanism is incompletely characterized. High sodium has been reported to increase vascular expression and vascular activity of ACE. To investigate whether high-dietary sodium-in

  6. High dietary sodium blunts effects of angiotensin-converting enzyme inhibition on vascular angiotensin I-to-angiotensin II conversion in rats

    NARCIS (Netherlands)

    Kocks, MJA; Buikema, H; Gschwend, S; Boomsma, F; de Zeeuw, D; Navis, G

    2003-01-01

    High sodium intake blunts the efficacy of angiotensin (Ang)-converting enzyme (ACE) inhibition (ACEi), but the underlying mechanism is incompletely characterized. High sodium has been reported to increase vascular expression and vascular activity of ACE. To investigate whether high-dietary sodium-in

  7. High dietary sodium blunts affects of angiotensin-converting enzyme inhibition on vascular angiotensin I-to-angiotensin II conversion in rats

    NARCIS (Netherlands)

    Kocks, Menno J A; Buikema, Hendrik; Gschwend, Simone; Boomsma, Frans; de Zeeuw, Dick; Navis, Gerjan

    2003-01-01

    High sodium intake blunts the efficacy of angiotensin (Ang)-converting enzyme (ACE) inhibition (ACEi), but the underlying mechanism is incompletely characterized. High sodium has been reported to increase vascular expression and vascular activity of ACE. To investigate whether high-dietary sodium-in

  8. High dietary sodium blunts affects of angiotensin-converting enzyme inhibition on vascular angiotensin I-to-angiotensin II conversion in rats

    NARCIS (Netherlands)

    Kocks, Menno J A; Buikema, Hendrik; Gschwend, Simone; Boomsma, Frans; de Zeeuw, Dick; Navis, Gerjan

    2003-01-01

    High sodium intake blunts the efficacy of angiotensin (Ang)-converting enzyme (ACE) inhibition (ACEi), but the underlying mechanism is incompletely characterized. High sodium has been reported to increase vascular expression and vascular activity of ACE. To investigate whether high-dietary

  9. High dietary sodium blunts effects of angiotensin-converting enzyme inhibition on vascular angiotensin I-to-angiotensin II conversion in rats

    NARCIS (Netherlands)

    Kocks, MJA; Buikema, H; Gschwend, S; Boomsma, F; de Zeeuw, D; Navis, G

    2003-01-01

    High sodium intake blunts the efficacy of angiotensin (Ang)-converting enzyme (ACE) inhibition (ACEi), but the underlying mechanism is incompletely characterized. High sodium has been reported to increase vascular expression and vascular activity of ACE. To investigate whether high-dietary

  10. Highly selective inhibition of histone demethylases by de novo macrocyclic peptides.

    Science.gov (United States)

    Kawamura, Akane; Münzel, Martin; Kojima, Tatsuya; Yapp, Clarence; Bhushan, Bhaskar; Goto, Yuki; Tumber, Anthony; Katoh, Takayuki; King, Oliver N F; Passioura, Toby; Walport, Louise J; Hatch, Stephanie B; Madden, Sarah; Müller, Susanne; Brennan, Paul E; Chowdhury, Rasheduzzaman; Hopkinson, Richard J; Suga, Hiroaki; Schofield, Christopher J

    2017-04-06

    The JmjC histone demethylases (KDMs) are linked to tumour cell proliferation and are current cancer targets; however, very few highly selective inhibitors for these are available. Here we report cyclic peptide inhibitors of the KDM4A-C with selectivity over other KDMs/2OG oxygenases, including closely related KDM4D/E isoforms. Crystal structures and biochemical analyses of one of the inhibitors (CP2) with KDM4A reveals that CP2 binds differently to, but competes with, histone substrates in the active site. Substitution of the active site binding arginine of CP2 to N-ɛ-trimethyl-lysine or methylated arginine results in cyclic peptide substrates, indicating that KDM4s may act on non-histone substrates. Targeted modifications to CP2 based on crystallographic and mass spectrometry analyses results in variants with greater proteolytic robustness. Peptide dosing in cells manifests KDM4A target stabilization. Although further development is required to optimize cellular activity, the results reveal the feasibility of highly selective non-metal chelating, substrate-competitive inhibitors of the JmjC KDMs.

  11. N-Nicotinoyl dopamine, a novel niacinamide derivative, retains high antioxidant activity and inhibits skin pigmentation.

    Science.gov (United States)

    Kim, Bora; Kim, Jin Eun; Lee, Su Min; Lee, Soung-Hoon; Lee, Jin Won; Kim, Myung Kyoo; Lee, Kye Jong; Kim, Hyuk; Lee, Joo Dong; Choi, Kang-Yell

    2011-11-01

    We synthesized a novel derivative of a well-known skin-lightening compound niacinamide, N-nicotinoyl dopamine (NND). NND did not show inhibitory effects of tyrosinase and melanin synthesis in B16F10 mouse melanoma cells. However, NND retains high antioxidant activity without affecting viability of cells. In a reconstructed skin model, topical applications of 0.05% and 0.1% NND induced skin lightening and decreased melanin production without affecting the viability and morphology of melanocytes and overall tissue histology. Moreover, no evidence for skin irritation or sensitization was observed when 0.1% NND emulsion was applied onto the skin of 52 volunteers. The effect of NND on skin lightening was further revealed by pigmented spot analyses of human clinical trial. Overall, NND treatment may be a useful trial for skin lightening and treating pigmentary disorders.

  12. High-fat feeding inhibits exercise-induced increase in mitochondrial respiratory flux in skeletal muscle.

    Science.gov (United States)

    Skovbro, Mette; Boushel, Robert; Hansen, Christina Neigaard; Helge, Jørn Wulff; Dela, Flemming

    2011-06-01

    Twenty one healthy untrained male subjects were randomized to follow a high-fat diet (HFD; 55-60E% fat, 25-30E% carbohydrate, and 15E% protein) or a normal diet (ND; 25-35E% fat, 55-60E% carbohydrate, and 10-15E% protein) for 2(1/2) wk. Diets were isocaloric and tailored individually to match energy expenditure. At 2(1/2) wk of diet, one 60-min bout of bicycle exercise (70% of maximal oxygen uptake) was performed. Muscle biopsies were obtained before and after the diet, immediately after exercise, and after 3-h recovery. Insulin sensitivity (hyperinsulinemic-euglycemic clamp) and intramyocellular triacylglycerol content did not change with the intervention in either group. Indexes of mitochondrial density were similar across the groups and intervention. Mitochondrial respiratory rates, measured in permeabilized muscle fibers, showed a 31 ± 11 and 26 ± 9% exercise-induced increase (P increase was abolished. At recovery, no change from resting respiration was seen in either group. With a lipid substrate (octanoyl-carnitine with or without ADP), similar exercise-induced increases (31-62%) were seen in HFD and ND, but only in HFD was an elevated (P fat-rich diet induces marked changes in the mitochondrial electron transport system protein content and in exercise-induced mitochondrial substrate oxidation rates, with the effects being present hours after the exercise. The effect of HFD is present even without effects on insulin sensitivity and intramyocellular lipid accumulation. An isocaloric high-fat diet does not cause insulin resistance.

  13. 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.

  14. Acute administration of high dose trimetazidine inhibits pentylenetetrazol-induced seizures in rats

    Directory of Open Access Journals (Sweden)

    Serkan GURGUL

    2017-03-01

    Full Text Available Objective: Resistant epilepsy is widely seen in clinical settings manipulate the researchers to pursuit novel anti-epileptic treatments. Although trimetazidine (TMZ is commonly used in the treatment of angina and ischemic diseases, it is considered that the drug may be beneficial in the treatment of epileptic seizures and convulsions. We aimed to evaluate electrophysiologically the protective effects of high dose acute TMZ on epileptic seizures and convulsions in a rat model of epilepsy induced by pentilentetrazol (PTZ. Method: Forty-eight male Sprague-Dawley rats were used for the EEG evaluation (Group-A; n=24 and behavioral assessment (Group-B; n=24. Grup-A1 and Grup-B1 were determined as control group and given no medication. 35 mg/kg (Group-A2, -A3 and -A4 and 70 mg/kg (Group-B2, -B3 and -B4 of PTZ were administered intraperitoneally (ip. so as to generate seizures and convulsions. Group-A2 and Group-B2 were treated with saline. 40 mg/kg (Grup-A3 and Grup-B3 and 80 mg/kg of TMZ (Group-A4 and Group-B4 were administered to the treatment groups by ip. Brain malondialdehyde (MDA levels, spike-percentage values, Racine’s Convulsion Scale (RCS scores and "first myoclonic jerk (FMJ" latencies of each rat were determined. Results: Brain MDA levels, spike-percentage values, RCS scores, and FMJ latencies of Group-A2 and Group-B2 were significantly increased compared to those of the control’s (Grup-A1 and Grup-B1 (P<0.05 for all comparisons. However, in TMZ treated groups (Group-A3 and -A4; Group-B3 and -B4 the elevated values of these parameters were found to be significantly decreased (P<0.05 for all comparisons. Conclusions: This study has demonstrated that the high dose acute TMZ administration may prevent PTZ-induced seizures and convulsions in rats. Furthermore, it can be also said that TMZ has a neuroprotective effects on oxidative stress associated with PTZ. Therefore, it may be considered for use with therapeutic purposes of TMZ in

  15. High plasma concentrations of asymmetric dimethylarginine inhibit ischemic cardioprotection in hypercholesterolemic rats

    Energy Technology Data Exchange (ETDEWEB)

    Landim, M.B.P.; Dourado, P.M.M.; Casella-Filho, A.; Chagas, A.C.P.; Luz, P.L. da [Unidade de Aterosclerose, Instituto do Coração, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP (Brazil)

    2013-05-10

    A low concentration of nitric oxide associated with a high concentration of asymmetric dimethylarginine (ADMA) can explain the lack of ischemic cardioprotection observed in the presence of hypercholesterolemia. The objective of the present study was to evaluate the effect of hypercholesterolemia on ischemic pre- and postconditioning and its correlation with plasma concentrations of ADMA. Male Wistar rats (6-8 weeks old) fed a 2% cholesterol diet (n = 21) for 8 weeks were compared to controls (n = 25) and were subjected to experimental myocardial infarction and reperfusion, with ischemic pre- and postconditioning. Total cholesterol and ADMA were measured in plasma before the experimental infarct and the infarct area was quantified. Weight, total cholesterol and plasma ADMA (means ± SE; 1.20 ± 0.06, 1.27 ± 0.08 and 1.20 ± 0.08 vs 0.97 ± 0.04, 0.93 ± 0.05 and 0.97 ± 0.04 µM) were higher in animals on the hypercholesterolemic diet than in controls, respectively. Cardioprotection did not reduce infarct size in the hypercholesterolemic animals (pre: 13.55% and post: 8% compared to 7.95% observed in the group subjected only to ischemia and reperfusion), whereas infarct size was reduced in the animals on a normocholesterolemic diet (pre: 8.25% and post: 6.10% compared to 12.31%). Hypercholesterolemia elevated ADMA and eliminated the cardioprotective effects of ischemic pre- and postconditioning in rats.

  16. The dipeptidyl peptidase 4 inhibitor vildagliptin does not accentuate glibenclamide-induced hypoglycemia but reduces glucose-induced glucagon-like peptide 1 and gastric inhibitory polypeptide secretion

    DEFF Research Database (Denmark)

    El-Ouaghlidi, Andrea; Rehring, Erika; Holst, Jens Juul

    2007-01-01

    BACKGROUND/AIMS: Inhibition of dipeptidyl peptidase 4 by vildagliptin enhances the concentrations of the active form of the incretin hormones glucagon-like peptide 1 (GLP-1) and gastric inhibitory polypeptide (GIP). The present study asked whether vildagliptin accentuates glibenclamide-induced hy...... of glibenclamide is not accentuated by the coadministration of vildagliptin. This may be explained by a negative feedback regulation of GLP-1 and GIP secretion that limits the degree to which the active incretin levels are enhanced....

  17. Inhibiting excessive acidification using zero-valent iron in anaerobic digestion of food waste at high organic load rates.

    Science.gov (United States)

    Kong, Xin; Wei, Yonghong; Xu, Shuang; Liu, Jianguo; Li, Huan; Liu, Yili; Yu, Shuyao

    2016-07-01

    Excessive acidification occurs frequently in food waste (FW) anaerobic digestion (AD) due to the high carbon-to-nitrogen ratio of FW. In this study, zero-valent iron (ZVI) was applied to prevent the excessive acidification. All of the control groups, without ZVI addition (pH∼5.3), produced little methane (CH4) and had high volatile fatty acids/bicarbonate alkalinity (VFA/ALK). By contrast, at OLR of 42.32gVS/Lreactor, the pH of effluent from the reactors with 0.4g/gVSFWadded of ZVI increased to 7.8-8.2, VFA/ALK decreased to <0.1, and the final CH4 yield was ∼380mL/gVSFWadded, suggesting inhibition of excessive acidification. After adding powdered or scrap metal ZVI to the acidogenic reactors, the fractional content of butyric acid changed from 30-40% to 0%, while, that of acetic acid increased. These results indicate that adding ZVI to FW digestion at high OLRs could eliminate excessive acidification by promoting butyric acid conversion and enhancing methanogen activity.

  18. Expression of 5-HT3 receptors by extrinsic duodenal afferents contribute to intestinal inhibition of gastric emptying.

    Science.gov (United States)

    Raybould, Helen E; Glatzle, Jorg; Robin, Carla; Meyer, James H; Phan, Thomas; Wong, Helen; Sternini, Catia

    2003-03-01

    Intestinal perfusion with carbohydrates inhibits gastric emptying via vagal and spinal capsaicin-sensitive afferent pathways. The aim of the present study was to determine the role of 1) 5-hydroxytryptamine (5-HT)(3) receptors (5-HT(3)R) in mediating glucose-induced inhibition of gastric emptying and 2) 5-HT(3)R expression in vagal and spinal afferents in innervating the duodenum. In awake rats fitted with gastric and duodenal cannulas, perfusion of the duodenum with glucose (50 and 100 mg) inhibited gastric emptying. Intestinal perfusion of mannitol inhibited gastric emptying only at the highest concentration (990 mosm/kgH(2)O). Pretreatment with the 5-HT(3)R antagonist tropisetron abolished both glucose- and mannitol-induced inhibition of gastric emptying. Retrograde labeling of visceral afferents by injection of dextran-conjugated Texas Red into the duodenal wall was used to identify extrinsic primary afferents. Immunoreactivity for 5-HT(3)R, visualized with an antibody directed to the COOH terminus of the rat 5-HT(3)R, was found in >80% of duodenal vagal and spinal afferents. These results show that duodenal extrinsic afferents express 5-HT(3)R and that the receptor mediates specific glucose-induced inhibition of gastric emptying. These findings support the hypothesis that enterochromaffin cells in the intestinal mucosa release 5-HT in response to glucose, which activates 5-HT(3)R on afferent nerve terminals to evoke reflex changes in gastric motility. The primary glucose sensors of the intestine may be mucosal enterochromaffin cells.

  19. Corosolic acid inhibits adipose tissue inflammation and ameliorates insulin resistance via AMPK activation in high-fat fed mice.

    Science.gov (United States)

    Yang, Jie; Leng, Jing; Li, Jing-Jing; Tang, Jing-fu; Li, Yi; Liu, Bao-Lin; Wen, Xiao-Dong

    2016-02-15

    Adipose tissue inflammation is tightly associated with the development of insulin resistance. Corosolic acid (CRA), a natural triterpenoid, is well known as "phyto-insulin" due to its insulin-like activities. However, its underlying mechanism remains unknown. In this study, we investigated the mechanisms of CRA on improving insulin resistance both in vivo and in vitro. C57BL/6 mice were fed with normal diet, high-fat diet (HFD) or HFD with CRA, respectively. General biochemical parameters in blood and glucose intolerance in mice were assayed. Meanwhile, proinflammatory cytokines and macrophage infiltrations in adipose tissues were analyzed by real-time PCR and immunohistochemical staining. The effects of CRA on insulin signaling transduction and AMPK activity in adipose tissues were investigated by western blot. Furthermore, the effects of CRA on AMPK were confirmed on 3T3-L1 cells by using both AMPK inhibitor and AMPKα1/2-specific siRNA RESULTS: CRA attenuated hyperlipidemia, improved insulin sensitivity and glucose intolerance in mice. Meanwhile, it alleviated inflammation in adipose tissues, demonstrated by the suppression of IKKβ phosphorylation and down-regulation of gene expressions of proinflammatory cytokines. Histological analysis revealed that CRA attenuated macrophage infiltrations into adipose tissue. It also improved insulin signaling transduction by modification of Ser/Thr phosphorylation of IRS-1 and downstream Akt, thereby improved insulin sensitivity in HFD-fed mice. Furthermore, CRA regulated AMPK activation in a LKB1-dependent manner. AMPKα knockdown in adipocytes abolished the inhibitory effects of CRA on IKKβ and IRS-1 serine phosphorylation, indicating that CRA inhibited inflammation and ameliorated insulin resistance via AMPK activation. CRA inhibited inflammation with improvement in adipose tissue dysfunction and ameliorated insulin resistance in an AMPK-dependent manner. Copyright © 2016 Elsevier GmbH. All rights reserved.

  20. 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.

  1. Inhibition of formyl peptide receptor in high-grade astrocytoma by CHemotaxis Inhibitory Protein of S. aureus.

    Science.gov (United States)

    Boer, J C; Domanska, U M; Timmer-Bosscha, H; Boer, I G J; de Haas, C J C; Joseph, J V; Kruyt, F A E; de Vries, E G E; den Dunnen, W F A; van Strijp, J A G; Walenkamp, A M E

    2013-02-19

    High-grade astrocytomas are malignant brain tumours that infiltrate the surrounding brain tissue and have a poor prognosis. Activation of formyl peptide receptor (FPR1) on the human astrocytoma cell line U87 promotes cell motility, growth and angiogenesis. We therefore investigated the FPR1 inhibitor, Chemotaxis Inhibitory Protein of S. aureus (CHIPS), as a potential anti-astrocytoma drug. FPR1 expression was studied immunohistochemically in astrocytomas WHO grades I-IV. With intracellular calcium mobilisation and migration assays, human ligands were tested for their ability to activate FPR1 on U87 cells and on a cell line derived from primary astrocytoma grade IV patient material. Thereafter, we selectively inhibited these ligand-induced responses of FPR1 with an anti-inflammatory compound called Chemotaxis Inhibitory Protein of S. aureus (CHIPS). U87 xenografts in NOD-SCID mice served to investigate the effects of CHIPS in vivo. FPR1 was expressed in 29 out of 32 (90%) of all grades of astrocytomas. Two human mitochondrial-derived formylated peptides, formyl-methionil-leucine-lysine-isoleucine-valine (fMLKLIV) and formyl-methionil-methionil-tyrosine-alanine-leucine-phenylalanine (fMMYALF), were potent activators of FPR1 on tumour cells. Ligand-induced responses of FPR1-expressing tumour cells could be inhibited with FPR1 inhibitor CHIPS. Treatment of tumour-bearing mice with CHIPS slightly reduced tumour growth and improved survival as compared to non-treated animals (P=0.0019). Targeting FPR1 with CHIPS reduces cell motility and tumour cell activation, and prolongs the survival of tumour-bearing mice. This strategy could be explored in future research to improve treatment results for astrocytoma patients.

  2. Inhibition of ileal bile acid uptake protects against nonalcoholic fatty liver disease in high-fat diet-fed mice.

    Science.gov (United States)

    Rao, Anuradha; Kosters, Astrid; Mells, Jamie E; Zhang, Wujuan; Setchell, Kenneth D R; Amanso, Angelica M; Wynn, Grace M; Xu, Tianlei; Keller, Brad T; Yin, Hong; Banton, Sophia; Jones, Dean P; Wu, Hao; Dawson, Paul A; Karpen, Saul J

    2016-09-21

    Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease in the Western world, and safe and effective therapies are needed. Bile acids (BAs) and their receptors [including the nuclear receptor for BAs, farnesoid X receptor (FXR)] play integral roles in regulating whole-body metabolism and hepatic lipid homeostasis. We hypothesized that interruption of the enterohepatic BA circulation using a luminally restricted apical sodium-dependent BA transporter (ASBT) inhibitor (ASBTi; SC-435) would modify signaling in the gut-liver axis and reduce steatohepatitis in high-fat diet (HFD)-fed mice. Administration of this ASBTi increased fecal BA excretion and messenger RNA (mRNA) expression of BA synthesis genes in liver and reduced mRNA expression of ileal BA-responsive genes, including the negative feedback regulator of BA synthesis, fibroblast growth factor 15. ASBT inhibition resulted in a marked shift in hepatic BA composition, with a reduction in hydrophilic, FXR antagonistic species and an increase in FXR agonistic BAs. ASBT inhibition restored glucose tolerance, reduced hepatic triglyceride and total cholesterol concentrations, and improved NAFLD activity score in HFD-fed mice. These changes were associated with reduced hepatic expression of lipid synthesis genes (including liver X receptor target genes) and normalized expression of the central lipogenic transcription factor, Srebp1c Accumulation of hepatic lipids and SREBP1 protein were markedly reduced in HFD-fed Asbt(-/-) mice, providing genetic evidence for a protective role mediated by interruption of the enterohepatic BA circulation. Together, these studies suggest that blocking ASBT function with a luminally restricted inhibitor can improve both hepatic and whole body aspects of NAFLD.

  3. Quantum dot nanoprobe-based high-content monitoring of notch pathway inhibition of breast cancer stem cell by capsaicin.

    Science.gov (United States)

    Shim, Yumi; Song, Joon Myong

    2015-12-01

    Breast cancer is the major cause of cancer death for women worldwide. Breast cancer patients are treated with chemotherapy and radiotherapy. Although chemotherapy and radiotherapy are applied, some cancer cells still survive. These cells, called cancer stem cell (CSC), exhibit special capabilities, such as drug and radio resistance. The remaining CSC can trigger cancer recurrence. Thus, it is critical to find an effective way to target CSC. Capsaicin has been reported to affect anticancer activity in many cancers. It also has been shown that capsaicin induces apoptosis in the MCF-7 breast cancer cell line. In this study, we demonstrate that capsaicin causes dose-dependent growth disruption in breast CSC and inhibits translocation of notch intracellular membrane domain (NICD) into the nucleus. MCF-7 cells were treated with capsaicin at various concentrations (5 μM, 10 μM, and 20 μM) for 24 h. After capsaicin treatment, it was found that the number of breast CSC (%) decreased as the treatment concentration of capsaicin increased. This result was also confirmed with FACS. NICD translocation to the nucleus and apoptotic cell death of breast CSC were concurrently observed at the single breast CSC level using highly sensitive quantum dot (Qdot)-antibody nanoprobes. The control breast CSCs without the capsaicin treatment were able to translocate NICD into the nucleus. On the other hand, translocation of NICD into the nucleus was not observed in capsaicin-treated cells. In addition, apoptotic cell death was caused when the breast CSC were treated with capsaicin at more than 10 μM. Although many studies have shown that capsaicin produces anticancer activity in cancer cell lines, the present result is the first report to demonstrate that capsaicin is capable of causing breast CSC apoptotic cell death via inhibiting its notch signaling pathway.

  4. High-fat diet intake from senescence inhibits the attenuation of cell functions and the degeneration of villi with aging in the small intestine, and inhibits the attenuation of lipid absorption ability in SAMP8 mice.

    Science.gov (United States)

    Yamamoto, Kazushi; E, Shuang; Hatakeyama, Yu; Sakamoto, Yu; Tsuduki, Tsuyoshi

    2015-11-01

    We examined the effect of a high-fat diet from senescence as a means of preventing malnutrition among the elderly. The senescence-accelerated mouse P8 was used and divided into three groups. The 6C group was given a normal diet until 6 months old. The 12N group was given a normal diet until 12 months old. The 12F group was given a normal diet until 6 months old and then a high-fat diet until 12 months old. In the oral fat tolerance test, there was a decrease in area under the curve for serum triacylglycerol level in the 12N group and a significant increase in the 12F group, suggesting that the attenuation of lipid absorption ability with aging was delayed by a high-fat diet from senescence. To examine this mechanism, histological analysis in the small intestine was performed. As a result, the degeneration of villi with aging was inhibited by the high-fat diet. There was also a significant decrease in length of villus in the small intestine in the 12N group and a significant increase in the 12F group. The high-fat diet from senescence inhibited the degeneration of villi with aging in the small intestine, and inhibited the attenuation of lipid absorption ability.

  5. A novel CCR2 antagonist inhibits atherogenesis in apoE deficient mice by achieving high receptor occupancy.

    Science.gov (United States)

    Bot, Ilze; Ortiz Zacarías, Natalia V; de Witte, Wilhelmus E A; de Vries, Henk; van Santbrink, Peter J; van der Velden, Daniël; Kröner, Mara J; van der Berg, Dirk-Jan; Stamos, Dean; de Lange, Elizabeth C M; Kuiper, Johan; IJzerman, Adriaan P; Heitman, Laura H

    2017-12-01

    CC Chemokine Receptor 2 (CCR2) and its endogenous ligand CCL2 are involved in a number of diseases, including atherosclerosis. Several CCR2 antagonists have been developed as potential therapeutic agents, however their in vivo clinical efficacy was limited. In this report, we aimed to determine whether 15a, an antagonist with a long residence time on the human CCR2, is effective in inhibiting the development of atherosclerosis in a mouse disease model. First, radioligand binding assays were performed to determine affinity and binding kinetics of 15a on murine CCR2. To assess the in vivo efficacy, western-type diet fed apoE(-/-) mice were treated daily with 15a or vehicle as control. Treatment with 15a reduced the amount of circulating CCR2(+) monocytes and the size of the atherosclerotic plaques in both the carotid artery and the aortic root. We then showed that the long pharmacokinetic half-life of 15a combined with the high drug concentrations ensured prolonged CCR2 occupancy. These data render 15a a promising compound for drug development and confirms high receptor occupancy as a key parameter when targeting chemokine receptors.

  6. High-throughput screening assays for CYP2B6 metabolism and inhibition using fluorogenic vivid substrates.

    Science.gov (United States)

    Marks, Bryan D; Goossens, Tony A; Braun, Heidi A; Ozers, Mary S; Smith, Ronald W; Lebakken, Connie; Trubetskoy, Olga V

    2003-01-01

    CYP2B6 is a highly polymorphic P450 isozyme involved in the metabolism of endo- and xenobiotics with known implications for the activation of many procarcinogens resulting in carcinogenesis. However, lack of validated high-throughput screening (HTS) CYP2B6 assays has limited the current understanding and full characterization of this isozyme's involvement in human drug metabolism. Here, we have developed and characterized a fluorescence-based HTS assay employing recombinant human CYP2B6 and 2 novel fluorogenic substrates (the Vivid CYP2B6 Blue and Cyan Substrates). Assay validation included testing the inhibitory potency of a panel of drugs and compounds known to be metabolized by this isozyme, including CYP2B6 substrates, inhibitors, and known inducers. Compound rankings based on inhibitory potency in the Vivid CYP2B6 Blue and Cyan Assays matched compound rankings based on relative affinity measurements from previously published data (K(i), K(d), or K(m) values) for the CYP2B6 isozyme. In conclusion, these assays are proven to be robust and sensitive, with broad dynamic ranges and kinetic parameters allowing screening in HTS mode of a large panel of compounds for CYP2B6 metabolism and inhibition, and are a valuable new tool for CYP2B6 studies.

  7. 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.

  8. Functional identification of activity-regulated, high-affinity glutamine transport in hippocampal neurons inhibited by riluzole.

    Science.gov (United States)

    Erickson, Jeffrey D

    2017-07-01

    Glutamine (Gln) is considered the preferred precursor for the neurotransmitter pool of glutamate (Glu), the major excitatory transmitter in the mammalian CNS. Here, an activity-regulated, high-affinity Gln transport system is described in developing and mature neuron-enriched hippocampal cultures that is potently inhibited by riluzole (IC50 1.3 ± 0.5 μM), an anti-glutamatergic drug, and is blocked by low concentrations of 2-(methylamino)isobutyrate (MeAIB), a system A transport inhibitor. K(+) -stimulated MeAIB transport displays an affinity (Km ) for MeAIB of 37 ± 1.2 μM, saturates at ~ 200 μM, is dependent on extracellular Ca(2+) , and is blocked by inhibition of voltage-gated Ca(2+) channels. Spontaneous MeAIB transport is also dependent on extracellullar Ca(2+) and voltage-gated calcium channels, but is also blocked by the Na(+) channel blocker tetrodotoxin, by Glu receptor antagonists, and by GABA indicating its dependence on intact neural circuits driven by endogenous glutamatergic activity. The transport of MeAIB itself does not rely on Ca(2+) , but on Na(+) ions, and is pH sensitive. Activity-regulated, riluzole-sensitive spontaneous and K(+) -stimulated transport is minimal at 7-8 days in vitro, coordinately induced during the next 2 weeks and is maximally expressed by days in vitro > 20; the known period for maturation of the Glu/Gln cycle and regulated pre-synaptic Glu release. Competition analyses with various amino acids indicate that Gln is the most likely physiological substrate. Activity-regulated Gln/MeAIB transport is not observed in astrocytes. The functional identification of activity-regulated, high-affinity, riluzole-sensitive Gln/MeAIB transport in hippocampal neurons may have important ramifications in the neurobiology of activity-stimulated pre-synaptic Glu release, the Glu/Gln cycle between astrocytes and neurons, and neuronal Glu-induced excitotoxicity. Cover Image for this issue: doi: 10.1111/jnc.13805. © 2017

  9. Inhibition of CPU0213, a Dual Endothelin Receptor Antagonist, on Apoptosis via Nox4-Dependent ROS in HK-2 Cells

    Directory of Open Access Journals (Sweden)

    Qing Li

    2016-06-01

    Full Text Available Background/Aims: Our previous studies have indicated that a novel endothelin receptor antagonist CPU0213 effectively normalized renal function in diabetic nephropathy. However, the molecular mechanisms mediating the nephroprotective role of CPU0213 remain unknown. Methods and Results: In the present study, we first detected the role of CPU0213 on apoptosis in human renal tubular epithelial cell (HK-2. It was shown that high glucose significantly increased the protein expression of Bax and decreased Bcl-2 protein in HK-2 cells, which was reversed by CPU0213. The percentage of HK-2 cells that showed Annexin V-FITC binding was markedly suppressed by CPU0213, which confirmed the inhibitory role of CPU0213 on apoptosis. Given the regulation of endothelin (ET system to oxidative stress, we determined the role of redox signaling in the regulation of CPU0213 on apoptosis. It was demonstrated that the production of superoxide (O2-. was substantially attenuated by CPU0213 treatment in HK-2 cells. We further found that CPU0213 dramatically inhibited expression of Nox4 protein, which gene silencing mimicked the role of CPU0213 on the apoptosis under high glucose stimulation. We finally examined the role of CPU0213 on ET-1 receptors and found that high glucose-induced protein expression of endothelin A and B receptors was dramatically inhibited by CPU0213. Conclusion: Taken together, these results suggest that this Nox4-dependenet O2- production is critical for the apoptosis of HK-2 cells in high glucose. Endothelin receptor antagonist CPU0213 has an anti-apoptosis role through Nox4-dependent O2-.production, which address the nephroprotective role of CPU0213 in diabetic nephropathy.

  10. Inhibition of tumor necrosis factor improves sleep continuity in patients with treatment resistant depression and high inflammation.

    Science.gov (United States)

    Weinberger, Jeremy F; Raison, Charles L; Rye, David B; Montague, Amy R; Woolwine, Bobbi J; Felger, Jennifer C; Haroon, Ebrahim; Miller, Andrew H

    2015-07-01

    Blockade of the inflammatory cytokine tumor necrosis factor (TNF) in depressed patients with increased inflammation has been associated with decreased depressive symptoms. Nevertheless, the impact of TNF blockade on sleep in depressed patients has not been examined. Accordingly, sleep parameters were measured using polysomnography in 36 patients with treatment resistant major depression at baseline and 2weeks after 3 infusions (week 8) of either the TNF antagonist infliximab (n=19) or placebo (n=17). Markers of inflammation including c-reactive protein (CRP) and TNF and its soluble receptors were also assessed along with depression measured by the 17-item Hamilton Depression Rating Scale. No differences in sleep parameters were found as a function of infliximab treatment over time. Nevertheless, wake after sleep onset (WASO), the spontaneous arousal index and sleep period time significantly decreased, and sleep efficiency significantly increased, from baseline to week 8 in infliximab-treated patients with high (CRP>5mg/L) (n=9) versus low inflammation (CRP⩽5mg/L) (n=10), controlling for changes in scores of depression. Stage 2 sleep also significantly decreased in infliximab-treated patients with high versus low inflammation. Decreases in soluble TNF receptor 1 (sTNFR1) significantly correlated with decreases in WASO and increases in sleep efficiency in infliximab-treated subjects with high inflammation. Placebo-treated subjects exhibited no sleep changes as a function of inflammation, and no correlations between inflammatory markers and sleep parameters in placebo-treated patients were found. These data suggest that inhibition of inflammation may be a viable strategy to improve sleep alterations in patients with depression and other disorders associated with increased inflammation.

  11. Fenugreek Seed Extract Inhibit Fat Accumulation and Ameliorates Dyslipidemia in High Fat Diet-Induced Obese Rats

    Directory of Open Access Journals (Sweden)

    Parveen Kumar

    2014-01-01

    Full Text Available This study investigated the inhibitory effect of aqueous extract of Trigonella foenum-graecum seeds (AqE-TFG on fat accumulation and dyslipidemia in high fat diet- (HFD- induced obese rats. Female Wistar rats were fed with HFD ad libitum, and the rats on HFD were treated orally with AqE-TFG or orlistat ((HFD for 28 days + AqE-TFG (0.5 and 1.0 g/kg or orlistat (10 mg/kg from day 8 to 28, respectively. Treatment with AqE-TFG produced significant reduction in body weight gain, body mass index (BMI, white adipose tissue (WAT weights, blood glucose, serum insulin, lipids, leptin, lipase, and apolipoprotein-B levels and elevation in adiponectin levels. AqE-TFG improved serum aspartate amino transferase (AST, alanine amino transferase (ALT, and lactate dehydrogenase (LDH levels. AqE-TFG treatment reduced the hepatic and cardiac thiobarbituric acid reactive substances (TBARS and elevated the antioxidant enzyme (glutathione (GSH, superoxide dismutase (SOD, and catalase (CAT levels. In addition, liver and uterine WAT lipogenic enzyme (fatty acid synthetase (FAS and glucose-6-phosphate dehydrogenase (G6PD activities were restored towards normal levels. These findings demonstrated the preventive effect of AqE-TFG on fat accumulation and dyslipidemia, due to inhibition of impaired lipid digestion and absorption, in addition to improvement in glucose and lipid metabolism, enhancement of insulin sensitivity, increased antioxidant defense, and downregulation of lipogenic enzymes.

  12. Postsynaptic inhibition mediates high-frequency selectivity in the cricket Teleogryllus oceanicus: implications for flight phonotaxis behavior.

    Science.gov (United States)

    Nolen, T G; Hoy, R R

    1987-07-01

    The frequency selectivity of the identified auditory interneuron, Int-1, in the cricket Teleogryllus oceanicus was examined using intracellular recording and staining techniques. Previous behavioral assays showed that crickets discriminate the low frequencies of the species calling song (4-5 kHz) from the high frequencies contained in the vocalizations of insectivorous bats (Nolen and Hoy, 1986a). Int-1 was excited by frequencies between 3 and 40 kHz, being similar, therefore, to the tympal organ (ear) in its broad range sensitivity; however, it responded differentially to high and low frequencies in terms of the number of action potentials evoked per stimulus tone pulse, the average discharge rate, and the latency of response. It was especially responsive to ultrasound (greater than 20 kHz), discharging at rates up to 400 spikes/sec (average rate), with 10 msec latencies; its response to pulses of the calling song was less than 150 spikes/sec, with 30 msec latencies. Int-1's dynamic range for ultrasound was also quite large, about 50 dB, compared to 20 dB for the calling song frequency. In addition, it responded well to trains of short, batlike pulses of ultrasound. These results are consistent with previous behavioral experiments showing that during flight, Int-1 was both necessary and sufficient for the ultrasound avoidance steering behavior (Nolen and Hoy, 1984), as long as it discharged above a rate of 180 spikes/sec. Ultrasound readily produced such high rates, whereas calling song rarely did; ultrasound reliably evoked avoidance steering over a wide dynamic range, while tone pulses of the calling song rarely did so (Nolen and Hoy, 1986a). A unique source of ipsilaterally mediated inhibition, tuned to the calling song frequency, accounted for the poor response to calling song and hence the neuron's high-frequency selectivity, and the behavioral and physiological effects of 2-tone suppression of high frequencies by the calling song (Nolen and Hoy, 1986b

  13. Transcription factor Ets-1 links glucotoxicity to pancreatic beta cell dysfunction through inhibiting PDX-1 expression in rodent models.

    Science.gov (United States)

    Chen, Fang; Sha, Min; Wang, Yanyang; Wu, Tijun; Shan, Wei; Liu, Jia; Zhou, Wenbo; Zhu, Yunxia; Sun, Yujie; Shi, Yuguang; Bleich, David; Han, Xiao

    2016-02-01

    'Glucotoxicity' is a term used to convey the negative effect of hyperglycaemia on beta cell function; however, the underlying molecular mechanisms that impair insulin secretion and gene expression are poorly defined. Our objective was to define the role of transcription factor v-ets avian erythroblastosis virus E26 oncogene homologue 1 (Ets-1) in beta cell glucotoxicity. Primary islets and Min6 cells were exposed to high glucose and Ets-1 expression was measured. Recombinant adenovirus and transgenic mice were used to upregulate Ets-1 expression in beta cells in vitro and in vivo, and insulin secretion was assessed. The binding activity of H3/H4 histone on the Ets-1 promoter, and that of forkhead box (FOX)A2, FOXO1 and Ets-1 on the Pdx-1 promoter was measured by chromatin immunoprecipitation and quantitative real-time PCR assay. High glucose induced upregulation of Ets-1 expression and hyperacetylation of histone H3 and H4 at the Ets-1 gene promoter in beta cells. Ets-1 overexpression dramatically suppressed insulin secretion and biosynthesis both in vivo and in vitro. Besides, Ets-1 overexpression increased the activity of FOXO1 but decreased that of FOXA2 binding to the pancreatic and duodenal homeobox 1 (PDX-1) homology region 2 (PH2), resulting in inhibition of Pdx-1 promoter activity and downregulation of PDX-1 expression and activity. In addition, high glucose promoted the interaction of Ets-1 and FOXO1, and the activity of Ets-1 binding to the Pdx-1 promoter. Importantly, PDX-1 overexpression reversed the defect in pancreatic beta cells induced by Ets-1 excess, while knockdown of Ets-1 prevented hyperglycaemia-induced dysfunction of pancreatic beta cells. Our observations suggest that Ets-1 links glucotoxicity to pancreatic beta cell dysfunction through inhibiting PDX-1 expression in type 2 diabetes.

  14. NT113, a pan-ERBB inhibitor with high brain penetrance, inhibits the growth of glioblastoma xenografts with EGFR amplification.

    Science.gov (United States)

    Yoshida, Yasuyuki; Ozawa, Tomoko; Yao, Tsun-Wen; Shen, Wang; Brown, Dennis; Parsa, Andrew T; Raizer, Jeffrey J; Cheng, Shi-Yuan; Stegh, Alexander H; Mazar, Andrew P; Giles, Francis J; Sarkaria, Jann N; Butowski, Nicholas; Nicolaides, Theodore; James, C David

    2014-12-01

    This report describes results from our analysis of the activity and biodistribution of a novel pan-ERBB inhibitor, NT113, when used in treating mice with intracranial glioblastoma (GBM) xenografts. Approaches used in this investigation include: bioluminescence imaging (BLI) for monitoring intracranial tumor growth and response to therapy; determination of survival benefit from treatment; analysis of tumor IHC reactivity for indication of treatment effect on proliferation and apoptotic response; Western blot analysis for determination of effects of treatment on ERBB and ERBB signaling mediator activation; and high-performance liquid chromatography for determination of NT113 concentration in tissue extracts from animals receiving oral administration of inhibitor. Our results show that NT113 is active against GBM xenografts in which wild-type EGFR or EGFRvIII is highly expressed. In experiments including lapatinib and/or erlotinib, NT113 treatment was associated with the most substantial improvement in survival, as well as the most substantial tumor growth inhibition, as indicated by BLI and IHC results. Western blot analysis results indicated that NT113 has inhibitory activity, both in vivo and in vitro, on ERBB family member phosphorylation, as well as on the phosphorylation of downstream signaling mediator Akt. Results from the analysis of animal tissues revealed significantly higher NT113 normal brain-to-plasma and intracranial tumor-to-plasma ratios for NT113, relative to erlotinib, indicating superior NT113 partitioning to intracranial tissue compartments. These data provide a strong rationale for the clinical investigation of NT113, a novel ERBB inhibitor, in treating patients with GBM.

  15. B56alpha/protein phosphatase 2A inhibits adipose lipolysis in high-fat diet-induced obese mice.

    Science.gov (United States)

    Kinney, Brice P; Qiao, Liping; Levaugh, Justin M; Shao, Jianhua

    2010-08-01

    Lipolysis and lipogenesis are two opposite processes that control lipid storage in adipocytes. Impaired adipose lipolysis has been observed in both obese human subjects and animal models. This study investigated the mechanisms underlying impaired adipose lipolysis in a high-fat diet-induced obese (DIO) mouse model. DIO models were created using male C57BL/6 mice. Our results show that beta3 adrenergic receptor-specific agonist BRL37344 induced adipose lipolysis was significantly blunted in DIO mice. The levels of Ser660 phosphorylation of hormone-sensitive lipase (HSL) were significantly decreased in the epididymal fat of DIO mice. However, protein levels of HSL, adipose triglyceride lipase and its coactivator comparative gene identification-58 were similar between DIO and control mice. It is known that upon lipolytic hormone stimulation, protein kinase A phosphorylates HSL Ser660 and activates HSL, whereas protein phosphatase 2A (PP2A) dephosphorylates and inactivates HSL. Interestingly, our study shows that high-fat feeding did not alter epididymal fat cAMP and protein kinase A protein levels but significantly increased the expression of the alpha-isoform of PP2A regulatory subunit B' (B56alpha). To study the role of B56alpha in obesity-associated lipolytic defect, B56alpha was overexpressed or knocked down by adenovirus-mediated gene transduction in cultured 3T3-L1CARDelta1 adipocytes. Overexpression of B56alpha significantly decreased HSL Ser660 phosphorylation. In contrast, knocking down B56alpha increased hormone-stimulated HSL activation and lipolysis in mature 3T3-L1CARDelta1 adipocytes. These results strongly suggest that elevated B56alpha/PP2A inhibits HSL and lipolysis in white adipose tissue of DIO mice.

  16. NEU-P11, a novel melatonin agonist, inhibits weight gain and improves insulin sensitivity in high-fat/high-sucrose-fed rats.

    Science.gov (United States)

    She, Meihua; Deng, Xiaojian; Guo, Zhenyu; Laudon, Moshe; Hu, Zhuowei; Liao, Duanfang; Hu, Xiaobo; Luo, Yi; Shen, Qingyun; Su, Zehong; Yin, Weidong

    2009-04-01

    Evidences indicate that a complex relationship exists among sleep disorders, obesity and insulin resistance. NEU-P11 is a novel melatonin agonist used in treatment of psychophysiological insomnia, and in animal studies NEU-P11 showed sleep-promoting effect. In this study, we applied NEU-P11 on obese rats to assess its potential melatoninergic effects in vivo. Obese models were established using high-fat/high-sucrose-fed for 5 months. NEU-P11 (10mg/kg)/melatonin (4mg/kg)/vehicle were administered by a daily intraperitoneal injection respectively for 8 weeks. Our results showed that NEU-P11 or melatonin inhibited both body weight gain and deposit of abdominal fat with no influence on food intake. The impaired insulin sensitivity and antioxidative potency were improved and the levels of plasma glucose, total cholesterol (TC), triglycerides (TG) decreased with an increased in HDL-cholesterol (HDL-c) after NEU-P11 or melatonin administration. These data suggest that NEU-P11, like melatonin, decreased body weight gain and improved insulin sensitivity and metabolic profiles in obese rats. We conclude that NEU-P11 has a melatoninergic effect on regulating body weight in obese rats and also improving metabolic profiles and efficiently enhancing insulin sensitivity.

  17. Seasonal effect of catecholamines on glucose-induced insulin secretion in the edible dormouse (Glis glis L.): in vivo and in vitro studies.

    Science.gov (United States)

    Castex, C; Le Bras, V; Hoo-Paris, R; Sutter, B C

    1983-04-01

    The results of the present study support the view that catecholamines are important for insulin secretion during the annual cycle of the edible dormouse exposed to seasonal changes in southwest France. Glucose tolerance tests and perfusion of the isolated pancreas have shown that in spring and summer, the B cell secretion mechanism is less sensitive to glucose than in other seasons. In spring and summer, insulin secretion induced by glucose is enhanced after in vivo and in vitro phentolamine treatment. The autumn and winter control insulin levels were not modified by phentolamine treatment. These results indicate that the inhibition of insulin secretion in spring and summer is due to noradrenaline liberated at the nerve endings adjacent to the B cells rather than to circulating catecholamines. This seasonal effect of noradrenaline may be attributed either to seasonal changes in the sensitivity of the alpha-adrenergic receptors of B cells or to an increase in noradrenaline release at the nerve endings in the islet during spring and summer.

  18. High stability and low competitive inhibition of thermophilic Thermopolyspora flexuosa GH10 xylanase in biomass-dissolving ionic liquids.

    Science.gov (United States)

    Anbarasan, Sasikala; Wahlström, Ronny; Hummel, Michael; Ojamo, Heikki; Sixta, Herbert; Turunen, Ossi

    2017-02-01

    Thermophilic Thermopolyspora flexuosa GH10 xylanase (TfXYN10A) was studied in the presence of biomass-dissolving hydrophilic ionic liquids (ILs) [EMIM]OAc, [EMIM]DMP and [DBNH]OAc. The temperature optimum of TfXYN10A with insoluble xylan in the pulp was at 65-70 °C, with solubilised 1 % xylan at 70-75 °C and with 3 % xylan at 75-80 °C. Therefore, the amount of soluble substrate affects the enzyme activity at high temperatures. The experiments with ILs were done with 1 % substrate. TfXYN10A can partially hydrolyse soluble xylan even in the presence of 40 % (v/v) ILs. Although ILs decrease the apparent temperature optimum, a surprising finding was that at the inactivating temperatures (80-90 °C), especially [EMIM]OAc increases the stability of TfXYN10A indicating that the binding of IL molecules strengthens the protein structure. Earlier kinetic studies showed an increased K m with ILs, indicating that ILs function as competitive inhibitors. TfXYN10A showed low increase of K m, which was 2-, 3- and 4-fold with 15 % [EMIM]OAc, [DBNH]OAc and [EMIM]DMP, respectively. One reason for the low competitive inhibition could be the high affinity to the substrate (low K m). Xylanases with low K m (~1 mg/mL) appear to show higher tolerance to ILs than xylanases with higher K m (~2 mg/mL). Capillary electrophoresis showed that TfXYN10A hydrolyses xylan to the end-products in 15-35 % ILs practically as completely as without IL, also indicating good binding of the short substrate molecules by TfXYN10A despite of major apparent IL binding sites above the catalytic residues. Substrate binding interactions in the active site appear to explain the high tolerance of TfXYN10A to ILs.

  19. 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.

  20. High-frequency transcutaneous electrical nerve stimulation alleviates spasticity after spinal contusion by inhibiting activated microglia in rats.

    Science.gov (United States)

    Hahm, Suk-Chan; Yoon, Young Wook; Kim, Junesun

    2015-05-01

    Transcutaneous electrical nerve stimulation (TENS) can be used as a physical therapy for spasticity, but the effects of TENS on spasticity and its underlying mechanisms remain unclear. The purpose of this study was to test the effects of TENS on spasticity and the role of activated microglia as underlying mechanisms of TENS treatment for spasticity in rats with a 50-mm contusive spinal cord injury (SCI). A spinal contusion was made at the T12 spinal segment in adult male Sprague-Dawley rats using the NYU impactor. Behavioral tests for motor function were conducted before and after SCI and before and after TENS application. To assess spasticity, the modified Ashworth scale (MAS) was used before and after SCI, high-frequency (HF)/low-frequency (LF) TENS application at 3 different intensities (motor threshold [MT], 50% and 90% MT) or minocycline administration. Immunohistochemistry for microglia was performed at the lumbar spinal segments. Motor recovery reached a plateau approximately 28 days after SCI. Spasticity was well developed and was sustained above the MAS grade of 3, beginning at 28 days after SCI. HF-TENS at 90% MT significantly alleviated spasticity. Motor function did not show any significant changes with LF- or HF-TENS treatment. HF-TENS significantly reduced the proportion of activated microglia observed after SCI. Minocycline, the microglia inhibitor, also significantly alleviated spasticity with the reduction of activated microglia expression. These results suggest that HF-TENS at 90% MT alleviates spasticity in rats with SCI by inhibiting activated microglia. © The Author(s) 2014.

  1. Dietary sphingomyelin lowers hepatic lipid levels and inhibits intestinal cholesterol absorption in high-fat-fed mice.

    Directory of Open Access Journals (Sweden)

    Rosanna W S Chung

    Full Text Available Controlling intestinal lipid absorption is an important strategy for maintaining lipid homeostasis. Accumulation of lipids in the liver is a major risk factor for metabolic syndrome and nonalcoholic fatty liver disease. It is well-known that sphingomyelin (SM can inhibit intestinal cholesterol absorption. It is, however, unclear if dietary SM also lowers liver lipid levels. In the present study (i the effect of pure dietary egg SM on hepatic lipid metabolism and intestinal cholesterol absorption was measured with [(14C]cholesterol and [(3H]sitostanol in male C57BL/6 mice fed a high-fat (HF diet with or without 0.6% wt/wt SM for 18 days; and (ii hepatic lipid levels and gene expression were determined in mice given a HF diet with or without egg SM (0.3, 0.6 or 1.2% wt/wt for 4 weeks. Mice supplemented with SM (0.6% wt/wt had significantly increased fecal lipid and cholesterol output and reduced hepatic [(14C]cholesterol levels after 18 days. Relative to HF-fed mice, SM-supplemented HF-fed mice had significantly lower intestinal cholesterol absorption (-30%. Liver weight was significantly lower in the 1.2% wt/wt SM-supplemented mice (-18%. Total liver lipid (mg/organ was significantly reduced in the SM-supplemented mice (-33% and -40% in 0.6% wt/wt and 1.2% wt/wt SM, respectively, as were triglyceride and cholesterol levels. The reduction in liver triglycerides was due to inactivation of the LXR-SREBP-1c pathway. In conclusion, dietary egg SM has pronounced hepatic lipid-lowering properties in mice maintained on an obesogenic diet.

  2. Consciously controlled breathing decreases the high-frequency component of heart rate variability by inhibiting cardiac parasympathetic nerve activity.

    Science.gov (United States)

    Sasaki, Konosuke; Maruyama, Ryoko

    2014-01-01

    Heart rate variability (HRV), the beat-to-beat alterations in heart rate, comprises sympathetic and parasympathetic nerve activities of the heart. HRV analysis is used to quantify cardiac autonomic regulation. Since respiration could be a confounding factor in HRV evaluation, some studies recommend consciously controlled breathing to standardize the method. However, it remains unclear whether controlled breathing affects HRV measurement. We compared the effects of controlled breathing on HRV with those of spontaneous breathing. In 20 healthy volunteers, we measured respiratory frequency (f), tidal volume, and blood pressure (BP) and recorded electrocardiograms during spontaneous breathing (14.8 ± 0.7 breaths/min) and controlled breathing at 15 (0.25 Hz) and 6 (0.10 Hz) breaths/min. Compared to spontaneous breathing, controlled breathing at 0.25 Hz showed a higher heart rate and a lower high-frequency (HF) component, an index of parasympathetic nerve activity, although the f was the same. During controlled breathing at 0.10 Hz, the ratio of the low frequency (LF) to HF components (LF/HF), an index of sympathetic nerve activity, increased greatly and HF decreased, while heart rate and BP remained almost unchanged. Thus, controlled breathing at 0.25 Hz, which requires mental concentration, might inhibit parasympathetic nerve activity. During controlled breathing at 0.10 Hz, LF/HF increases because some HF subcomponents are synchronized with f and probably move into the LF band. This increment leads to misinterpretation of the true autonomic nervous regulation. We recommend that the respiratory pattern of participants should be evaluated before spectral HRV analysis to correctly understand changes in autonomic nervous regulation.

  3. Modeling psychotic and cognitive symptoms of affective disorders: Disrupted latent inhibition and reversal learning deficits in highly stress reactive mice.

    Science.gov (United States)

    Knapman, A; Heinzmann, J-M; Holsboer, F; Landgraf, R; Touma, C

    2010-09-01

    Increased stress reactivity has repeatedly been reported in patients suffering from psychiatric diseases including schizophrenia and major depression. These disorders also have other symptoms in common, such as cognitive deficits and psychotic-like behavior. We have therefore investigated if increased stress reactivity is associated with these phenotypic endpoints in an animal model of affective disorders. The stress reactivity mouse model used in this study consists of three CD-1-derived mouse lines, that have been selectively bred for high (HR), intermediate (IR) or low (LR) stress reactivity. Male mice from these three breeding lines were subjected to a reversal learning task and latent inhibition (Li) was assessed using a conditioned taste aversion paradigm. Furthermore, as the dopaminergic system is involved in both Li and reversal learning, the dopamine 1 receptor (D1R), dopamine 2 receptor (D2R) and dopamine transporter (DAT) mRNA expression levels were assessed in relevant brain areas of these animals. The results demonstrate that HR mice show perseveration in the reversal learning task and have disrupted Li. Furthermore, compared to LR mice, HR mice have decreased D2R mRNA levels in the ventral tegmental area, as well as decreased D1R mRNA levels in the cingulate cortex, and an increased expression of D2R mRNA in the nucleus accumbens. Taken together, these results demonstrate that the HR mice display cognitive deficits associated with psychotic-like behavior, similar to those observed in patients suffering from schizophrenia and major depression and could be utilized in the search for better treatment strategies for these symptoms of psychiatric disorders.

  4. High-resolution bacterial growth inhibition profiling combined with HPLC-HRMS-SPE-NMR for identification of antibacterial constituents in Chinese plants used to treat snakebites

    DEFF Research Database (Denmark)

    Liu, Yueqiu; Nielsen, Mia; Stærk, Dan

    2014-01-01

    assay. The most active extracts were fractionated into microplates using analytical-scale RP-HPLC, and subsequently growth inhibition was assessed for each well. The biochromatograms constructed from these assays were used to identify compounds responsible for antibacterial activity. The structures...... of five compounds were elucidated by HPLC–HRMS–SPE–NMR. Results Crude extracts of Boehmeria nivea, Colocasia esculenta, Fagopyrum cymosum, Glochidion puberum, Melastoma dodecandrum, Polygonum bistorta, Polygonum cuspidatum and Sanguisorba officinalis showed MIC values below 200 μg/mL against either...... growth inhibition profiling combined with HPLC–HRMS–SPE–NMR allowed fast identification of three non-tannin active compounds, i.e., piceid, resveratrol and emodin from ethanol extract of Polygonum cuspidatum. Conclusion The high-resolution bacterial growth inhibition profiling allowed fast pinpointing...

  5. High NaCl-induced inhibition of PTG contributes to activation of NFAT5 through attenuation of the negative effect of SHP-1.

    Science.gov (United States)

    Zhou, Xiaoming; Wang, Hong; Burg, Maurice B; Ferraris, Joan D

    2013-08-01

    Activation of the transcription factor NFAT5 by high NaCl involves changes in phosphorylation. By siRNA screening, we previously found that protein targeting to glycogen (PTG), a regulatory subunit of protein phosphatase1 (PP1), contributes to regulation of high NaCl-induced NFAT5 transcriptional activity. The present study addresses the mechanism involved. We find that high NaCl-induced inhibition of PTG elevates NFAT5 activity by increasing NFAT5 transactivating activity, protein abundance, and nuclear localization. PTG acts via a catalytic subunit PP1γ. PTG associates physically with PP1γ, and NaCl reduces both this association and remaining PTG-associated PP1γ activity. High NaCl-induced phosphorylation of p38, ERK, and SHP-1 contributes to activation of NFAT5. Knockdown of PTG does not affect phosphorylation of p38 or ERK. However, PTG and PP1γ bind to SHP-1, and knockdown of either PTG or PP1γ increases high NaCl-induced phosphorylation of SHP-1-S591, which inhibits SHP-1. Mutation of SHP-1-S591 to alanine, which cannot be phosphorylated, increases inhibition of NFAT5 by SHP-1. Thus high NaCl reduces the stimulatory effect of PTG and PP1γ on SHP-1, which in turn reduces the inhibitory effect of SHP-1 on NFAT5. Our findings add to the known functions of PTG, which was previously recognized only for its glycogenic activity.

  6. High concentrations of L-ascorbic acid specifically inhibit the growth of human leukemic cells via downregulation of HIF-1α transcription.

    Directory of Open Access Journals (Sweden)

    Hiroshi Kawada

    Full Text Available We examined the antileukemic effects of high concentrations of L-ascorbic acid (high AA on human leukemic cells. In vitro, high AA markedly induced apoptosis in various leukemic cell lines by generating hydrogen peroxide (H2O2 but not in normal hematopoietic stem/progenitor cells. High AA significantly repressed leukemic cell proliferation as well as neoangiogenesis in immunodeficient mice. We then noted that in leukemic cells, HIF-1α transcription was strongly suppressed by high AA and correlated with the transcription of VEGF. Our data indicate that exposure to high AA markedly increased the intracellular AA content of leukemic cells and inhibited the nuclear translocation of NF-κB, which mediates expression of HIF-1α. We next generated K562 cells that overexpressed HIF-1α (K562-HIF1α cells and assessed the mechanistic relationship between inhibition of HIF-1α transcription and the antileukemic effect of high AA. The ability of high AA to induce apoptosis was significantly lower in K562-HIF1α cells than in K562 cells in vitro. We found that expression of HIF-1α-regulated antiapoptotic proteins of the Bcl-2 family, such as Mcl-1, Bcl-xL, and Bcl-2, was significantly suppressed by high AA in K562 cells, but was sustained at higher levels in K562-HIF1α cells, regardless of high AA exposure. Moreover, repression of cell proliferation and neoangiogenesis by high AA was completely abrogated in mice receiving transplants of K562-HIF1α cells. These results indicate that, along with H2O2 generation, downregulation of HIF-1α transcription plays a crucial role in growth inhibition of human leukemic cells by high AA.

  7. Glucose-induced downregulation of angiotensin II and arginine vasopressin receptors in cultured rat aortic vascular smooth muscle cells. Role of protein kinase C.

    OpenAIRE

    Williams, B.; Tsai, P.; Schrier, R W

    1992-01-01

    Early diabetes mellitus is characterized by impaired responses to pressor hormones and pressor receptor downregulation. The present study examined the effect of elevated extracellular glucose concentrations on angiotensin II (AII) and arginine vasopressin (AVP) receptor kinetics in cultured rat vascular smooth muscle cells (VSMC). Scatchard analysis of [3H]AVP and 125I-AII binding to confluent VSMC showed that high glucose concentrations (20 mM) similarly depressed AVP and AII surface recepto...

  8. Decavanadate binding to a high affinity site near the myosin catalytic centre inhibits F-actin-stimulated myosin ATPase activity.

    Science.gov (United States)

    Tiago, Teresa; Aureliano, Manuel; Gutiérrez-Merino, Carlos

    2004-05-11

    Decameric vanadate (V(10)) inhibits the actin-stimulated myosin ATPase activity, noncompetitively with actin or with ATP upon interaction with a high-affinity binding site (K(i) = 0.27 +/- 0.05 microM) in myosin subfragment-1 (S1). The binding of V(10) to S1 can be monitored from titration with V(10) of the fluorescence of S1 labeled at Cys-707 and Cys-697 with N-iodo-acetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine (IAEDANS) or 5-(iodoacetamido) fluorescein, which showed the presence of only one V(10) binding site per monomer with a dissociation constant of 0.16-0.7 microM, indicating that S1 labeling with these dyes produced only a small distortion of the V(10) binding site. The large quenching of AEDANS-labeled S1 fluorescence produced by V(10) indicated that the V(10) binding site is close to Cys-697 and 707. Fluorescence studies demonstrated the following: (i) the binding of V(10) to S1 is not competitive either with actin or with ADP.V(1) or ADP.AlF(4); (ii) the affinity of V(10) for the complex S1/ADP.V(1) and S1/ADP.AlF(4) is 2- and 3-fold lower than for S1; and (iii) it is competitive with the S1 "back door" ligand P(1)P(5)-diadenosine pentaphosphate. A local conformational change in S1 upon binding of V(10) is supported by (i) a decrease of the efficiency of fluorescence energy transfer between eosin-labeled F-actin and fluorescein-labeled S1, and (ii) slower reassociation between S1 and F-actin after ATP hydrolysis. The results are consistent with binding of V(10) to the Walker A motif of ABC ATPases, which in S1 corresponds to conserved regions of the P-loop which form part of the phosphate tube.

  9. Premotor spinal network with balanced excitation and inhibition during motor patterns has high resilience to structural division

    DEFF Research Database (Denmark)

    Petersen, Peter C; Vestergaard, Mikkel; Reveles Jensen, Kristian

    2014-01-01

    Direct measurements of synaptic inhibition (I) and excitation (E) to spinal motoneurons can provide an important insight into the organization of premotor networks. Such measurements of flexor motoneurons participating in motor patterns in turtles have recently demonstrated strong concurrent E an...

  10. Carnitine palmitoyl transferase-I inhibition is not associated with cardiac hypertrophy in rats fed a high fat diet

    Science.gov (United States)

    Cardiac lipotoxicity is characterized by hypertrophy and contractile dysfunction and can be triggered by impaired mitochondrial fatty acid oxidation and lipid accumulation. The present study investigated the effect of dietary fatty acid intake alone and in combination with inhibition of mitochondria...

  11. The blunting of the antiproteinuric efficacy of ACE inhibition by high sodium intake can be restored by hydrochlorothiazide

    NARCIS (Netherlands)

    Buter, H.; Hemmelder, M.H.; Navis, Ger Jan; De Jong, P.E.; de Zeeuw, Dick

    1998-01-01

    Background. Dietary sodium restriction enhances the antiproteinuric and blood pressure lowering effect of ACE inhibition. In clinical practice, however, long-term compliance to a low-sodium diet may be difficult to obtain. We therefore investigated whether the blunting of the antiproteinuric and blo

  12. Combination of Vorinostat and caspase-8 inhibition exhibits high anti-tumoral activity on endometrial cancer cells.

    Science.gov (United States)

    Bergadà, Laura; Sorolla, Annabel; Yeramian, Andree; Eritja, Nuria; Mirantes, Cristina; Matias-Guiu, Xavier; Dolcet, Xavier

    2013-08-01

    Histone deacetylase inhibitors such as Vorinostat display anti-neoplastic activity against a variety of solid tumors. Here, we have investigated the anti-tumoral activity of Vorinostat on endometrial cancer cells. We have found that Vorinostat caused cell growth arrest, loss of clonogenic growth and apoptosis of endometrial cancer cells. Vorinostat-induced the activation of caspase-8 and -9, the initiators caspases of the extrinsic and the intrinsic apoptotic pathways, respectively. Next, we investigated the role of the extrinsic pathway in apoptosis triggered by Vorinostat. We found that Vorinostat caused a dramatic decrease of FLIP mRNA and protein levels. However, overexpression of the long from of FLIP did not block Vorinostat-induced apoptosis. To further investigate the role of extrinsic apoptotic pathway in Vorinostat-induced apoptosis, we performed an shRNA-mediated knock-down of caspase-8. Surprisingly, downregulation of caspase-8 alone caused a marked decrease in clonogenic ability and reduced the growth of endometrial cancer xenografts in vivo, revealing that targeting caspase-8 may be an attractive target for anticancer therapy on endometrial tumors. Furthermore, combination of caspase-8 inhibition and Vorinostat treatment caused an enhancement of apoptotic cell death and a further decrease of clonogenic growth of endometrial cancer cells. More importantly, combination of Vorinostat and caspase-8 inhibition caused a nearly complete inhibition of tumor xenograft growth. Finally, we demonstrate that cell death triggered by Vorinostat alone or in combination with caspase-8 shRNAs was inhibited by the anti-apoptotic protein Bcl-XL. Our results suggest that combinatory therapies using Vorinostat treatment and caspase-8 inhibition can be an effective treatment for endometrial carcinomas. Copyright © 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  13. MicroRNA-134 Contributes to Glucose-Induced Endothelial Cell Dysfunction and This Effect Can Be Reversed by Far-Infrared Irradiation.

    Directory of Open Access Journals (Sweden)

    Hsei-Wei Wang

    Full Text Available Diabetes mellitus (DM is a metabolic disease that is increasing worldwide. Furthermore, it is associated with the deregulation of vascular-related functions, which can develop into major complications among DM patients. Endothelial colony forming cells (ECFCs have the potential to bring about medical repairs because of their post-natal angiogenic activities; however, such activities are impaired by high glucose- (HG and the DM-associated conditions. Far-infrared radiation (FIR transfers energy as heat that is perceived by the thermoreceptors in human skin. Several studies have revealed that FIR improves vascular endothelial functioning and boost angiogenesis. FIR has been used as anti-inflammatory therapy and as a clinical treatment for peripheral circulation improvement. In addition to vascular repair, there is increasing evidence to show that FIR can be applied to a variety of diseases, including cardiovascular disorders, hypertension and arthritis. Yet mechanism of action of FIR and the biomarkers that indicate FIR effects remain unclear. MicroRNA-134 (miR-134-5p was identified by small RNA sequencing as being increased in high glucose (HG treated dfECFCs (HG-dfECFCs. Highly expressed miR-134 was also validated in dmECFCs by RT-qPCR and it is associated with impaired angiogenic activities of ECFCs. The functioning of ECFCs is improved by FIR treatment and this occurs via a reduction in the level of miR-134 and an increase in the NRIP1 transcript, a direct target of miR-134. Using a mouse ischemic hindlimb model, the recovery of impaired blood flow in the presence of HG-dfECFCs was improved by FIR pretreatment and this enhanced functionality was decreased when there was miR-134 overexpression in the FIR pretreated HG-dfECFCs. In conclusion, our results reveal that the deregulation of miR-134 is involved in angiogenic defects found in DM patients. FIR treatment improves the angiogenic activity of HG-dfECFCs and dmECFCs and FIR has potential as

  14. Cooperation between HMGA1, PDX-1, and MafA is Essential for Glucose-Induced Insulin Transcription in Pancreatic Beta Cells.

    Science.gov (United States)

    Arcidiacono, Biagio; Iiritano, Stefania; Chiefari, Eusebio; Brunetti, Francesco S; Gu, Guoqiang; Foti, Daniela Patrizia; Brunetti, Antonio

    2014-01-01

    The high-mobility group AT-hook 1 (HMGA1) protein is a nuclear architectural factor that can organize chromatin structures. It regulates gene expression by controlling the formation of stereospecific multiprotein complexes called "enhanceosomes" on the AT-rich regions of target gene promoters. Previously, we reported that defects in HMGA1 caused decreased insulin receptor expression and increased susceptibility to type 2 diabetes mellitus in humans and mice. Interestingly, mice with disrupted HMGA1 gene had significantly smaller islets and decreased insulin content in their pancreata, suggesting that HMGA1 may have a direct role in insulin transcription and secretion. Herein, we investigate the regulatory roles of HMGA1 in insulin transcription. We provide evidence that HMGA1 physically interacts with PDX-1 and MafA, two critical transcription factors for insulin gene expression and beta-cell function, both in vitro and in vivo. We then show that the overexpression of HMGA1 significantly improves the transactivating activity of PDX-1 and MafA on human and mouse insulin promoters, while HMGA1 knockdown considerably decreased this transactivating activity. Lastly, we demonstrate that high glucose stimulus significantly increases the binding of HMGA1 to the insulin (INS) gene promoter, suggesting that HMGA1 may act as a glucose-sensitive element controlling the transcription of the INS gene. Together, our findings provide evidence that HMGA1, by regulating PDX-1- and MafA-induced transactivation of the INS gene promoter, plays a critical role in pancreatic beta-cell function and insulin production.

  15. Cooperation between HMGA1, PDX-1 and MafA is essential for glucose-induced insulin transcription in pancreatic beta cells

    Directory of Open Access Journals (Sweden)

    Biagio eArcidiacono

    2015-01-01

    Full Text Available The high-mobility group AT-hook 1 (HMGA1 protein is a nuclear architectural factor that can organize chromatin structures. It regulates gene expression by controlling the formation of stereospecific multiprotein complexes called enhanceosomes on the AT-rich regions of target gene promoters. Previously, we reported that defects in HMGA1 caused decreased insulin receptor expression and increased susceptibility to type 2 diabetes mellitus in humans and mice. Interestingly, mice with disrupted HMGA1 gene had significantly smaller islets and decreased insulin content in their pancreata, suggesting that HMGA1 may have a direct role in insulin transcription and secretion. Herein, we investigate the regulatory roles of HMGA1 in insulin transcription. We provide evidence that HMGA1 physically interacts with PDX-1 and MafA, two critical transcription factors for insulin gene expression and beta-cell function, both in vitro and in vivo. We then show that the overexpression of HMGA1 significantly improves the transactivating activity of PDX-1 and MafA on human and mouse insulin promoters, while HMGA1 knockdown considerably decreased this transactivating activity. Lastly, we demonstrate that high glucose stimulus significantly increases the binding of HMGA1 to the insulin (INS gene promoter, suggesting that HMGA1 may act as a glucose-sensitive element controlling the transcription of the INS gene. Together, our findings provide evidence that HMGA1, by regulating PDX-1- and MafA-induced transactivation of the INS gene promoter, plays a critical role in pancreatic beta-cell function and insulin production.

  16. 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.

  17. 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.

  18. Myxoma Virus dsRNA Binding Protein M029 Inhibits the Type I IFN-Induced Antiviral State in a Highly Species-Specific Fashion

    Science.gov (United States)

    Rahman, Masmudur M.; McFadden, Grant

    2017-01-01

    Myxoma virus (MYXV) is a Leporipoxvirus that possesses a specific rabbit-restricted host tropism but exhibits a much broader cellular host range in cultured cells. MYXV is able to efficiently block all aspects of the type I interferon (IFN)-induced antiviral state in rabbit cells, partially in human cells and very poorly in mouse cells. The mechanism(s) of this species-specific inhibition of type I IFN-induced antiviral state is not well understood. Here we demonstrate that MYXV encoded protein M029, a truncated relative of the vaccinia virus (VACV) E3 double-stranded RNA (dsRNA) binding protein that inhibits protein kinase R (PKR), can also antagonize the type I IFN-induced antiviral state in a highly species-specific manner. In cells pre-treated with type I IFN prior to infection, MYXV exploits M029 to overcome the induced antiviral state completely in rabbit cells, partially in human cells, but not at all in mouse cells. However, in cells pre-infected with MYXV, IFN-induced signaling is fully inhibited even in the absence of M029 in cells from all three species, suggesting that other MYXV protein(s) apart from M029 block IFN signaling in a species-independent manner. We also show that the antiviral state induced in rabbit, human or mouse cells by type I IFN can inhibit M029-knockout MYXV even when PKR is genetically knocked-out, suggesting that M029 targets other host proteins for this antiviral state inhibition. Thus, the MYXV dsRNA binding protein M029 not only antagonizes PKR from multiple species but also blocks the type I IFN antiviral state independently of PKR in a highly species-specific fashion. PMID:28157174

  19. Cholesterol reduction ameliorates glucose-induced calcium handling and insulin secretion in islets from low-density lipoprotein receptor knockout mice.

    Science.gov (United States)

    Souza, J C; Vanzela, E C; Ribeiro, R A; Rezende, L F; de Oliveira, C A; Carneiro, E M; Oliveira, H C F; Boschero, A C

    2013-04-01

    Changes in cellular cholesterol level may contribute to beta cell dysfunction. Islets from low density lipoprotein receptor knockout (LDLR(-/-)) mice have higher cholesterol content and secrete less insulin than wild-type (WT) mice. Here, we investigated the association between cholesterol content, insulin secretion and Ca(2+) handling in these islets. Isolated islets from both LDLR(-/-) and WT mice were used for measurements of insulin secretion (radioimmunoassay), cholesterol content (fluorimetric assay), cytosolic Ca(2+) level (fura-2AM) and SNARE protein expression (VAMP-2, SNAP-25 and syntaxin-1A). Cholesterol was depleted by incubating the islets with increasing concentrations (0-10mmol/l) of methyl-beta-cyclodextrin (MβCD). The first and second phases of glucose-stimulated insulin secretion (GSIS) were lower in LDLR(-/-) than in WT islets, paralleled by an impairment of Ca(2+) handling in the former. SNAP-25 and VAMP-2, but not syntaxin-1A, were reduced in LDLR(-/-) compared with WT islets. Removal of excess cholesterol from LDLR(-/-) islets normalized glucose- and tolbutamide-induced insulin release. Glucose-stimulated Ca(2+) handling was also normalized in cholesterol-depleted LDLR(-/-) islets. Cholesterol removal from WT islets by 0.1 and 1.0mmol/l MβCD impaired both GSIS and Ca(2+) handling. In addition, at 10mmol/l MβCD WT islet showed a loss of membrane integrity and higher DNA fragmentation. Abnormally high (LDLR(-/-) islets) or low cholesterol content (WT islets treated with MβCD) alters both GSIS and Ca(2+) handling. Normalization of cholesterol improves Ca(2+) handling and insulin secretion in LDLR(-/-) islets. Copyright © 2013 Elsevier B.V. All rights reserved.

  20. Inhibition of platelet function by abciximab or high-dose tirofiban in patients with STEMI undergoing primary PCI: a randomised trial

    Science.gov (United States)

    van Werkum, J.W.; Gerritsen, W.B.M.; Kelder, J.C.; Hackeng, C.M.; Ernst, S.M.; Deneer, V.H.M.; Suttorp, M.J.; Rensing, B.J.W.M.; Plokker, H.W.M.; ten Berg, J.M.

    2007-01-01

    Background In patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI, few data exist on the magnitude of platelet activation, aggregation and dosing of glycoprotein (GP) IIb/IIIa receptor inhibitors. Methods Sixty STEMI patients were randomised to abciximab, to high-dose tirofiban or to no additional GP IIb/IIIa inhibitor treatment. Platelet activation (P-selectin expression) was measured using flow cytometry and the level of inhibition of platelet aggregation was assessed using the Plateletworks assay. Additionally, the PFA-100 with the collagen/adenosine-diphosphate cartridge (CADP) was used to compare the levels of platelet inhibition. All measurements were performed at baseline (T0), immediately after (T1), 30 minutes (T2), 60 minutes (T3) and 120 minutes (T4) after primary PCI. Results The level of platelet activation in both GP IIb/IIIa receptor inhibitor treated groups was significantly lower compared with the control group at all time points after primary PCI (p=0.04). Also the administration of the currently recommended dose of abciximab resulted in significantly lower levels of inhibition of aggregation compared with high-dose tirofiban (p<0.0001). In addition, the CADP closure times were significantly prolonged in both GP IIb/IIIa inhibitor treated groups compared with the control group at time points T1 (p=0.006) and T4 (p<0.0001). Conclusion The administration of high-dose tirofiban resulted in a significantly higher inhibition of platelet aggregation compared with the currently recommended dose of abciximab. Large clinical trials are needed to assess whether this laboratory superiority of high-dose tirofiban translates into higher clinical efficacy. (Neth Heart J 2007;15:375-81.18176639) PMID:18176639

  1. Inhibition of 5-HT neuron activity and induction of depressive-like behavior by high-frequency stimulation of the subthalamic nucleus

    OpenAIRE

    Temel, Yasin; Boothman, Laura J.; Blokland, Arjan; Magill, Peter J; Steinbusch, Harry W. M.; Visser-Vandewalle, Veerle; Sharp, Trevor

    2007-01-01

    Bilateral, high-frequency stimulation (HFS) of the subthalamic nucleus (STN) is the surgical therapy of choice for movement disability in advanced Parkinson's disease (PD), but this procedure evokes debilitating psychiatric effects, including depressed mood, of unknown neural origin. Here, we report the unexpected finding that HFS of the STN inhibits midbrain 5-hydroxytryptamine (5-HT) neurons to evoke depression-related behavioral changes. We found that bilateral HFS of the STN consistently ...

  2. 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...

  3. siRNAs targeting PB2 and NP genes potentially inhibit replication of Highly Pathogenic H5N1 Avian Influenza Virus.

    Science.gov (United States)

    Behera, Padmanava; Nagarajan, Shanmugasundaram; Murugkar, Harshad V; Kalaiyarasu, Semmannan; Prakash, Anil; Gothalwal, Ragini; Dubey, Shiv Chandra; Kulkarni, Diwakar D; Tosh, Chakradhar

    2015-06-01

    Highly Pathogenic Avian Influenza (HPAI) H5N1 virus is a threat to animal and public health worldwide. Till date, the H5N1 virus has claimed 402 human lives, with a mortality rate of 58 percent and has caused the death or culling of millions of poultry since 2003. In this study, we have designed three siRNAs (PB2-2235, PB2-479 and NP-865) targeting PB2 and NP genes of avian influenza virus and evaluated their potential, measured by hemagglutination (HA), plaque reduction and Real time RT-PCR assay, in inhibiting H5N1 virus (A/chicken/Navapur/7972/2006) replication in MDCK cells. The siRNAs caused 8- to 16-fold reduction in virus HA titers at 24 h after challenged with 100TCID50 of virus. Among these siRNAs, PB2-2235 offered the highest inhibition of virus replication with 16-fold reduction in virus HA titer, 80 percent reduction in viral plaque counts and 94 percent inhibition in expression of specific RNA at 24 h. The other two siRNAs had 68-73 percent and 87-88 percent reduction in viral plaque counts and RNA copy number, respectively. The effect of siRNA on H5N1 virus replication continued till 48h (maximum observation period). These findings suggest that PB2-2235 could efficiently inhibit HPAI H5N1 virus replication.

  4. Dopamine Inhibits High-Frequency Stimulation-Induced Long-Term Potentiation of Intrinsic Excitability in CA1 Hippocampal Pyramidal Neurons

    Directory of Open Access Journals (Sweden)

    Chun-ling Wei

    2012-09-01

    Full Text Available The efficiency of neural circuits is modified by changes not only in synaptic strength, but also in intrinsic excitability of neurons. In CA1 hippocampal pyramidal neurons, bidirectional changes in the intrinsic excitability are often presented after induction of synaptic long-term potentiation or depression. This plasticity of intrinsic excitability has been identified as a cellular correlate of learning. Besides, behavioral learning often involves action of reinforcement or rewarding mediated by dopamine (DA. Here, we examined how DA influences the intrinsic plasticity of CA1 hippocampal pyramidal neurons when high-frequency stimulation (HFS was applied to Schaffer collaterals. The results showed that DA inhibits the decrease in rheobase and increase in mean firing rate of pyramidal neurons induced by HFS, and that this inhibition was abolished by the D1-like receptor antagonist SCH23390 but not by the D2-like receptor antagonist sulpiride. The results suggest that DA inhibits the potentiation of excitability induced by presynaptic HFS, and that this inhibition depends on the activation of D1-like receptors.

  5. siRNAs targeting PB2 and NP genes potentially inhibit replication of Highly Pathogenic H5N1 Avian Influenza Virus

    Indian Academy of Sciences (India)

    Padmanava Behera; Shanmugasundaram Nagarajan; Harshad V Murugkar; Semmannan Kalaiyarasu; Anil Prakash; Ragini Gothalwal; Shiv Chandra Dubey; Diwakar D Kulkarni; Chakradhar Tosh

    2015-06-01

    Highly Pathogenic Avian Influenza (HPAI) H5N1 virus is a threat to animal and public health worldwide. Till date, the H5N1 virus has claimed 402 human lives, with a mortality rate of 58% and has caused the death or culling of millions of poultry since 2003. In this study, we have designed three siRNAs (PB2-2235, PB2-479 and NP-865) targeting PB2 and NP genes of avian influenza virus and evaluated their potential, measured by hemagglutination (HA), plaque reduction and Real time RT-PCR assay, in inhibiting H5N1 virus (A/chicken/Navapur/7972/2006) replication in MDCK cells. The siRNAs caused 8- to 16-fold reduction in virus HA titers at 24 h after challenged with 100TCID50 of virus. Among these siRNAs, PB2-2235 offered the highest inhibition of virus replication with 16-fold reduction in virus HA titer, 80% reduction in viral plaque counts and 94% inhibition in expression of specific RNA at 24 h. The other two siRNAs had 68–73% and 87–88% reduction in viral plaque counts and RNA copy number, respectively. The effect of siRNA on H5N1 virus replication continued till 48h (maximum observation period). These findings suggest that PB2-2235 could efficiently inhibit HPAI H5N1 virus replication.

  6. 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-induced

  7. Task-dependent inhibition of slow-twitch soleus and excitation of fast-twitch gastrocnemius do not require high movement speed and velocity-dependent sensory feedback

    Directory of Open Access Journals (Sweden)

    Ricky eMehta

    2014-10-01

    Full Text Available Although individual heads of triceps surae, soleus (SO and medial gastrocnemius (MG muscles, are often considered close functional synergists, previous studies have shown distinct activity patterns between them in some motor behaviors. The goal of this study was to test two hypotheses explaining inhibition of slow SO with respect to fast MG: (1 inhibition occurs at high movement velocities and mediated by velocity-dependent sensory feedback and (2 inhibition depends on the ankle-knee joint moment combination and does not require high movement velocities. The hypotheses were tested by comparing the SO EMG/MG EMG ratio during fast and slow motor behaviors (cat paw shake responses vs. back, straight leg load lifting in humans, which had the same ankle extension-knee flexion moment combination; and during fast and slow behaviors with the ankle extension-knee extension moment combination (human vertical jumping and stance phase of walking in cats and leg load lifting in humans. In addition, SO EMG/MG EMG ratio was determined during cat paw shake responses and walking before and after removal of stretch velocity-dependent sensory feedback by self-reinnervating SO and/or gastrocnemius. We found the ratio SO EMG/MG EMG below 1 (p<0.05 during fast paw shake responses and slow back load lifting, requiring the ankle extension-knee flexion moment combination; whereas the ratio SO EMG/MG EMG was above 1 (p<0.05 during fast vertical jumping and slow tasks of walking and leg load lifting, requiring ankle extension-knee extension moments. Removal of velocity-dependent sensory feedback did not affect the SO EMG/MG EMG ratio in cats. We concluded that the relative inhibition of SO does not require high muscle velocities, depends on ankle-knee moment combinations, and is mechanically advantageous for allowing a greater MG contribution to ankle extension and knee flexion moments.

  8. A Novel Mannose-binding Lectin/Ficolin-associated Protein Is Highly Expressed in Heart and Skeletal Muscle Tissues and Inhibits Complement Activation

    DEFF Research Database (Denmark)

    Skjoedt, M.-o.; Hummelshoj, T.; Palarasah, Y.

    2010-01-01

    -terminal amino acids. By use of quantitative PCR and MAP-1-specific immunohistochemistry, we found that MAP-1 is highly expressed in myocardial and skeletal muscle tissues as well as in liver hepatocytes with a different expression profile than that observed for MASP-1 and MASP-3. MAP-1 co-precipitated from...... human serum with MBL, ficolin-2, and ficolin-3, and recombinant MAP-1 was able to inhibit complement C4 deposition via both the ficolin-3 and MBL pathway. In conclusion we have identified a novel 45-kDa serum protein derived from the MASP1 gene, which is highly expressed in striated muscle tissues...

  9. MicroRNA-495 Inhibits Gastric Cancer Cell Migration and Invasion Possibly via Targeting High Mobility Group AT-Hook 2 (HMGA2)

    Science.gov (United States)

    Wang, Huashe; Jiang, Zhipeng; Chen, Honglei; Wu, Xiaobin; Xiang, Jun; Peng, Junsheng

    2017-01-01

    Background Gastric cancer is one of the most common malignancies, and has a high mortality rate. miR-495 acts as a suppressor in some cancers and HMGA2 (high mobility group AT-hook 2) is a facilitator for cell growth and epithelial-mesenchymal transition (EMT), but little is known about their effect in gastric cancer. This study aimed to investigate the role and mechanism of miR-495 in gastric cancer. Material/Methods miR-495 levels were quantitatively analyzed in gastric cancer tissue and GES-1, SGC-7901, BGC-823, and HGC-27 cell lines by qRT-PCR. Levels of miR-495 and HMGA2 were altered by cell transfection, after which cell migration and invasion were examined by Transwell and E-cadherin (CDH1); vimentin (VIM), and alpha smooth muscle actin (ACTA2) were detected by qRT-PCR and Western blotting. The interaction between miR-495 and HMGA2 was verified by dual-luciferase reporter assay. Results miR-495 was significantly downregulated in cancer tissue and cell lines (pgastric cancer tissue, and promoted cell migration and invasion, inhibited CDH1, and elevated VIM and ACTA2. Conclusions miR-495 acts as a tumor suppressor in gastric cancer by inhibiting cell migration and invasion, which may be associated with its direct inhibition on HMGA2. These results suggest a promising therapeutic strategy for gastric cancer treatment. PMID:28159956

  10. Instant coffee extract with high chlorogenic acids content inhibits hepatic G-6-Pase in vitro, but does not reduce the glycaemia.

    Science.gov (United States)

    Bassoli, Bruna Kempfer; Cassolla, Priscila; Borba-Murad, Glaucia Regina; Constantin, Jorgete; Salgueiro-Pagadigorria, Clairce Luzia; Bazotte, Roberto Barbosa; de Souza, Helenir Medri

    2015-06-01

    Coffee is the main source of chlorogenic acid in the human diet, and it contains several chlorogenic acid isomers, of which the 5-caffeoylquinic acid (5-CQA) is the predominant isomer. Because there are no available data about the action of chlorogenic acids from instant coffee on hepatic glucose-6-phosphatase (G-6-Pase) activity and blood glucose levels, these effects were investigated in rats. The changes on G-6-Pase activity and liver glucose output induced by 5-CQA were also investigated. Instant coffee extract with high chlorogenic acids content (37.8%) inhibited (p  0.05). Similarly, 5-CQA (1 mM) reduced (p  0.05) on glucose output arising from glycogenolysis in liver perfusion. It was concluded that instant coffee extract with high content of chlorogenic acids inhibited hepatic G-6-Pase in vitro, but failed to reduce the glycaemia probably because the coffee chlorogenic acids did not reach enough levels within the hepatocytes to inhibit the G-6-Pase and reduce the liver glucose output.

  11. Intracytoplasmic stable expression of IgG1 antibody targeting NS3 helicase inhibits replication of highly efficient hepatitis C Virus 2a clone

    Directory of Open Access Journals (Sweden)

    Clementi Massimo

    2010-06-01

    Full Text Available Abstract Background Hepatitis C virus (HCV infection is a major public health problem with more than 170 million cases of chronic infections worldwide. There is no protective vaccine currently available for HCV, therefore the development of novel strategy to prevent chronic infection is important. We reported earlier that a recombinant human antibody clone blocks viral NS3 helicase activity and inhibits replication of HCV 1b virus. This study was performed further to explore the mechanism of action of this recombinant antibody and to determine whether or not this antibody inhibits replication and infectivity of a highly efficient JFH1 HCV 2a virus clone. Results The antiviral effect of intracellular expressed antibody against the HCV 2a virus strain was examined using a full-length green fluorescence protein (GFP labeled infectious cell culture system. For this purpose, a Huh-7.5 cell line stably expressing the NS3 helicase gene specific IgG1 antibody was prepared. Replication of full-length HCV-GFP chimera RNA and negative-strand RNA was strongly inhibited in Huh-7.5 cells stably expressing NS3 antibody but not in the cells expressing an unrelated control antibody. Huh-7.5 cells stably expressing NS3 helicase antibody effectively suppressed infectious virus production after natural infection and the level of HCV in the cell free supernatant remained undetectable after first passage. In contrast, Huh-7.5 cells stably expressing an control antibody against influenza virus had no effect on virus production and high-levels of infectious HCV were detected in culture supernatants over four rounds of infectivity assay. A recombinant adenovirus based expression system was used to demonstrate that Huh-7.5 replicon cell line expressing the intracellular antibody strongly inhibited the replication of HCV-GFP RNA. Conclusion Recombinant human anti-HCV NS3 antibody clone inhibits replication of HCV 2a virus and infectious virus production. Intracellular

  12. Inhibition of angiotensin-1-converting enzyme activity by two varieties of ginger (Zingiber officinale) in rats fed a high cholesterol diet.

    Science.gov (United States)

    Akinyemi, Ayodele Jacob; Ademiluyi, Adedayo Oluwaseun; Oboh, Ganiyu

    2014-03-01

    Angiotensin-1-converting enzyme (ACE) inhibitors are widely used in the treatment of cardiovascular diseases. This study sought to investigate the inhibitory effect of two varieties of ginger (Zingiber officinale) commonly consumed in Nigeria on ACE activity in rats fed a high cholesterol diet. The inhibition of ACE activity of two varieties of ginger (Z. officinale) was investigated in a high cholesterol (2%) diet fed to rats for 3 days. Feeding high cholesterol diets to rats caused a significant (Pginger varieties. Rats that were fed 4% white ginger had the greatest inhibitory effect as compared with a control diet. Furthermore, there was a significant (Pginger (either 2% or 4%) caused a significant (Pginger had the greatest reduction as compared with control diet. In conclusion, both ginger varieties exhibited anti-hypercholesterolemic properties in a high cholesterol diet fed to rats. This activity of the gingers may be attributed to its ACE inhibitory activity. However, white ginger inhibited ACE better in a high cholesterol diet fed to rats than red ginger. Therefore, both gingers could serve as good functional foods/nutraceuticals in the management/treatment of hypertension and other cardiovascular diseases.

  13. All-trans-Retinoic Acid Ameliorated High Fat Diet-Induced Atherosclerosis in Rabbits by Inhibiting Platelet Activation and Inflammation

    Directory of Open Access Journals (Sweden)

    Birong Zhou

    2012-01-01

    Full Text Available Background. All-trans-retinoic acid (atRA is effective for many proliferative diseases. We investigated the protective effects of atRA against atherosclerosis. Methods. Rabbits were randomly allocated to receive basal diet or an HFD for 4 weeks. HFD group then received rosuvastatin (3 mg/day, atRA (5 mg/kg/day, or the same volume of vehicle, respectively, for next 8 weeks. Results. HFD group showed increases in plasma lipids and aortic plaque formation. P-selectin expression and fibrinogen binding on platelets or deposition on the intima of the aorta also increased significantly as did the levels of TNF-α, IL-6, and fibrinogen in plasma. After 8 weeks of treatment with atRA, there was a significant decrease in plasma lipids and improvement in aortic lesions. AtRA also inhibited the expression of P-selectin and fibrinogen binding on platelets and deposition on the intima of the aorta. Conclusion. AtRA can ameliorate HFD-induced AS in rabbits by inhibiting platelet activation and inflammation.

  14. Biogas production from undiluted chicken manure and maize silage: A study of ammonia inhibition in high solids anaerobic digestion.

    Science.gov (United States)

    Sun, Chen; Cao, Weixing; Banks, Charles J; Heaven, Sonia; Liu, Ronghou

    2016-10-01

    The feasibility of co-digestion of chicken manure (CM) and maize silage (MS) without water dilution was investigated in 5-L digesters. Specific methane production (SMP) of 0.309LCH4g(-1) volatile solids (VS) was achieved but only at lower %CM. Above a critical threshold for total ammonia nitrogen (TAN), estimated at 7gNL(-1), VFA accumulated with a characteristic increase in acetic acid followed by its reduction and an increase in propionic acid. During this transition the predominant methanogenic pathway was hydrogenotrophic. Methanogenesis was completely inhibited at TAN of 9gNL(-1). The low digestibility of the mixed feedstock led to a rise in digestate TS and a reduction in SMP over the 297-day experimental period. Methanogenesis appeared to be failing in one digester but was recovered by reducing the %CM. Co-digestion was feasible with CM ⩽20% of feedstock VS, and the main limiting factor was ammonia inhibition. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. 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.

  16. Intergranular stress corrosion cracking of type 304 stainless steels treated with inhibitive chemicals in high temperature pure water

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, T.K. [Nuclear Science and Technology Development Center, National Tsing-Hua Univ. Taiwan (China); Lee, M.Y.; Tsai, C.H. [Department of Engineering and System Science, National Tsing-Hua Univ. Taiwan (China)

    2002-07-01

    Electrochemical potentiodynamic polarizations, electrochemical corrosion potential (ECP) measurements and slow strain rate tensile (SSRT) tests were conducted to investigate the intergranular stress corrosion cracking (IGSCC) characteristics of Type 304 stainless steels treated with inhibitive chemicals in simulated boiling water reactor (BWR) environments. A number of thermally sensitized specimens were prepared and were pre-oxidized in a 288 C environment with the presence of 300 ppb dissolved oxygen for 360 hours. Most of the specimens were then treated with various chemicals including powdered zirconium oxide (ZrO{sub 2}), powdered titanium oxide (TiO{sub 2}), and zirconyl nitrate [ZrO(NO{sub 3}){sub 2}] via static immersion at 90 C, 150 C, and 200 C. Test environments were specifically designed in a circulation loop to create a dissolved oxygen concentration of 300 ppb. Test results showed that the corrosion current densities of all treated specimens were lower than that of the untreated, pre-oxidized specimen at ambient temperature in a solution mixed with 1 mM K{sub 3}Fe(CN){sub 6} and 1 mM K{sub 4}Fe(CN){sub 6}. The ECPs of the treated specimens could be lower or higher than that of the pre-oxidized one at 288 C, depending upon the type of treating chemical and the treating temperature. In addition, IGSCC was observed on all specimens (treated or untreated) in the same environment. However, the untreated specimen exhibited lower elongation, shorter failure time, and more secondary cracks on the side surfaces. It was therefore suggested that inhibitive chemicals such as ZrO{sub 2}, TiO{sub 2}, and ZrO(NO{sub 3}){sub 2} did provide a certain degree of enhancement in improving the mechanical behavior of the treated specimens and in prolonging the IGSCC initiation time. (authors)

  17. Inhibition of human high-affinity copper importer Ctr1 orthologous in the nervous system of Drosophila ameliorates Aβ42-induced Alzheimer's disease-like symptoms.

    Science.gov (United States)

    Lang, Minglin; Fan, Qiangwang; Wang, Lei; Zheng, Yajun; Xiao, Guiran; Wang, Xiaoxi; Wang, Wei; Zhong, Yi; Zhou, Bing

    2013-11-01

    Disruption of copper homeostasis has been implicated in Alzheimer's disease (AD) during the last 2 decades; however, whether copper is a friend or a foe is controversial. Within a genetically tractable Drosophila AD model, we manipulated the expression of human high-affinity copper importer orthologous in Drosophila to explore the in vivo roles of copper ions in the development of AD. We found that inhibition of Ctr1C expression by RNAi in Aβ-expressing flies significantly reduced copper accumulation in the brains of the flies as well as ameliorating neurodegeneration, enhancing climbing ability, and prolonging lifespan. Interestingly, Ctr1C inhibition led to a significant increase in higher-molecular-weight Aβ42 forms in brain lysates, whereas it was accompanied by a trend of decreased expression of amyloid-β degradation proteases (including NEP1-3 and IDE) with age and reduced Cu-Aβ interaction-induced oxidative stress in Ctr1C RNAi flies. Similar results were obtained from inhibiting another copper importer Ctr1B and overexpressing a copper exporter DmATP7 in the nervous system of AD flies. These results imply that copper may play a causative role in developing AD, as either Aβ oligomers or aggregates were less toxic in a reduced copper environment or one with less copper binding. Early manipulation of brain copper uptake can have a great effect on Aβ pathology.

  18. High-Throughput Sequencing Identifies MicroRNAs from Posterior Intestine of Loach (Misgurnus anguillicaudatus) and Their Response to Intestinal Air-Breathing Inhibition.

    Science.gov (United States)

    Huang, Songqian; Cao, Xiaojuan; Tian, Xianchang; Wang, Weimin

    2016-01-01

    MicroRNAs (miRNAs) exert important roles in animal growth, immunity, and development, and regulate gene expression at the post-transcriptional level. Knowledges about the diversities of miRNAs and their roles in accessory air-breathing organs (ABOs) of fish remain unknown. In this work, we used high-throughput sequencing to identify known and novel miRNAs from the posterior intestine, an important ABO, in loach (Misgurnus anguillicaudatus) under normal and intestinal air-breathing inhibited conditions. A total of 204 known and 84 novel miRNAs were identified, while 47 miRNAs were differentially expressed between the two small RNA libraries (i.e. between the normal and intestinal air-breathing inhibited group). Potential miRNA target genes were predicted by combining our transcriptome data of the posterior intestine of the loach under the same conditions, and then annotated using COG, GO, KEGG, Swissprot and Nr databases. The regulatory networks of miRNAs and their target genes were analyzed. The abundances of nine known miRNAs were validated by qRT-PCR. The relative expression profiles of six known miRNAs and their eight corresponding target genes, and two novel potential miRNAs were also detected. Histological characteristics of the posterior intestines in both normal and air-breathing inhibited group were further analyzed. This study contributes to our understanding on the functions and molecular regulatory mechanisms of miRNAs in accessory air-breathing organs of fish.

  19. Entry Inhibition of Influenza Viruses with High Mannose Binding Lectin ESA-2 from the Red Alga Eucheuma serra through the Recognition of Viral Hemagglutinin

    Directory of Open Access Journals (Sweden)

    Yuichiro Sato

    2015-05-01

    Full Text Available Lectin sensitivity of the recent pandemic influenza A virus (H1N1-2009 was screened for 12 lectins with various carbohydrate specificity by a neutral red dye uptake assay with MDCK cells. Among them, a high mannose (HM-binding anti-HIV lectin, ESA-2 from the red alga Eucheuma serra, showed the highest inhibition against infection with an EC50 of 12.4 nM. Moreover, ESA-2 exhibited a wide range of antiviral spectrum against various influenza strains with EC50s of pico molar to low nanomolar levels. Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2. Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA, was demonstrated by ELISA assay. This interaction was effectively suppressed by glycoproteins bearing HM-glycans, indicating that ESA-2 binds to the HA of influenza virus through HM-glycans. Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells. ESA-2 would thus be useful as a novel microbicide to prevent penetration of viruses such as HIV and influenza viruses to the host cells.

  20. Entry Inhibition of Influenza Viruses with High Mannose Binding Lectin ESA-2 from the Red Alga Eucheuma serra through the Recognition of Viral Hemagglutinin.

    Science.gov (United States)

    Sato, Yuichiro; Morimoto, Kinjiro; Kubo, Takanori; Sakaguchi, Takemasa; Nishizono, Akira; Hirayama, Makoto; Hori, Kanji

    2015-05-29

    Lectin sensitivity of the recent pandemic influenza A virus (H1N1-2009) was screened for 12 lectins with various carbohydrate specificity by a neutral red dye uptake assay with MDCK cells. Among them, a high mannose (HM)-binding anti-HIV lectin, ESA-2 from the red alga Eucheuma serra, showed the highest inhibition against infection with an EC50 of 12.4 nM. Moreover, ESA-2 exhibited a wide range of antiviral spectrum against various influenza strains with EC50s of pico molar to low nanomolar levels. Besides ESA-2, HM-binding plant lectin ConA, fucose-binding lectins such as fungal AOL from Aspergillus oryzae and AAL from Aleuria aurantia were active against H1N1-2009, but the potency of inhibition was of less magnitude compared with ESA-2. Direct interaction between ESA-2 and a viral envelope glycoprotein, hemagglutinin (HA), was demonstrated by ELISA assay. This interaction was effectively suppressed by glycoproteins bearing HM-glycans, indicating that ESA-2 binds to the HA of influenza virus through HM-glycans. Upon treatment with ESA-2, no viral antigens were detected in the host cells, indicating that ESA-2 inhibited the initial steps of virus entry into the cells. ESA-2 would thus be useful as a novel microbicide to prevent penetration of viruses such as HIV and influenza viruses to the host cells.

  1. Endomorphins inhibit high-threshold Ca2+ channel currents in rodent NG108-15 cells overexpressing mu-opioid receptors.

    Science.gov (United States)

    Higashida, H; Hoshi, N; Knijnik, R; Zadina, J E; Kastin, A J

    1998-02-15

    1. Extracellular application of the novel brain peptides endomorphin 1 (EM1) and endomorphin 2 (EM2) inhibited high-threshold Ca2+ channel currents in NGMO-251 cells, a daughter clone of NG108-15 mouse neuroblastoma x rat glioma hybrid cells, in which mu-opioid receptors are overexpressed. 2. In contrast, EM1 and EM2 did not induce this inhibition in the parental NG108-15 cells that predominantly express endogenous delta-receptors. 3. The IC50 for EM1 and EM2 was 7.7 and 23.1 nM, respectively. 4. EM-induced Ca2+ channel current inhibition was blocked by treatment or pretreatment of the cells with 100 microM N-methylmaleimide or 100 ng ml-1 pertussis toxin. 5. These results show that a decrease in conductance of Ca2+ channels results following interaction of EMs with cloned mu-receptors, which couple via Gi/Go-type G proteins, and that EMs fulfill one of the necessary synaptic conditions for them to be identified as neurotransmitters.

  2. Resveratrol improves high fat diet-induced fatty liver and insulin resistance by concomitant inhibiting proteolytic cleavage of SREBPS , FFAs oxidation, and intestinal TGS absorption.

    Science.gov (United States)

    Khaleel, Eman F; Abdel-Aleem, Ghada Ahmed; Mostafa, Dalia Gamal Eldin

    2017-08-04

    Resveratrol (RES) has the ability to ameliorate non-alcoholic fatty liver disease (NAFLD) and the mechanism remains unclear. Hence, using high-fat diet (HFD) obese rat model, we investigated the effect of low dose of RES (20 mg/kg) on hepatic Sterol regulatory element-binding proteins (SREBPs)-lipogenesis pathway, enzymes involved in β-oxidation and activity of pancreatic lipase. 4 groups of rats (n=8) of either control (12 % of calories as fat) or HFD (40 % of calories as fat), both were administered with either normal saline as vehicle or RES as a concomitant treatment for 8 weeks on a daily basis, orally. Then, various biochemical, histological and molecular experiments were carried out. RES prevented the development and progression of NAFLD and significantly improved insulin sensitivity through 1) inhibiting the proteolytic cleavage of SREBPs-1 and SREBPs-2 without affecting their precursor mRNA or protein levels 2) inhibiting FFA beta-oxidation and generation of ROS through significant inhibition of CPT-1 and UCP-2, 3) decreasing activity of pancreatic lipase in vivo and in-vitro. In conclusion, Our findings are the first in the literature to show new mechanisms of hepatoprotective effect of RES against HFD induced NAFLD in rats.

  3. High-density lipoprotein inhibits ox-LDL-induced adipokine secretion by upregulating SR-BI expression and suppressing ER Stress pathway.

    Science.gov (United States)

    Song, Guohua; Wu, Xia; Zhang, Pu; Yu, Yang; Yang, Mingfeng; Jiao, Peng; Wang, Ni; Song, Haiming; Wu, You; Zhang, Xiangjian; Liu, Huaxia; Qin, Shucun

    2016-07-29

    Endoplasmic reticulum stress (ERS) in adipocytes can modulate adipokines secretion. The aim of this study was to explore the protective effect of high-density lipoprotein (HDL) on oxidized low-density lipoprotein (ox-LDL)-induced ERS-C/EBP homologous protein (CHOP) pathway-mediated adipokine secretion. Our results showed that serum adipokines, including visfatin, resistin and TNF-α, correlated inversely with serum HDL cholesterol level in patients with abdominal obesity. In vitro, like ERS inhibitor 4-phenylbutyric acid (PBA), HDL inhibited ox-LDL- or tunicamycin (TM, an ERS inducer)-induced increase in visfatin and resistin secretion. Moreover, HDL inhibited ox-LDL-induced free cholesterol (FC) accumulation in whole cell lysate and in the endoplasmic reticulum. Additionally, like PBA, HDL inhibited ox-LDL- or TM-induced activation of ERS response as assessed by the decreased phosphorylation of protein kinase-like ER kinase and eukaryotic translation initiation factor 2α and reduced nuclear translocation of activating transcription factor 6 as well as the downregulation of Bip and CHOP. Furthermore, HDL increased scavenger receptor class B type I (SR-BI) expression and SR-BI siRNA treatment abolished the inhibitory effects of HDL on ox-LDL-induced FC accumulation and CHOP upregulation. These data indicate that HDL may suppress ox-LDL-induced FC accumulation in adipocytes through upregulation of SR-BI, subsequently preventing ox-LDL-induced ER stress-CHOP pathway-mediated adipocyte inflammation.

  4. Isoliquiritigenin inhibits TNF-α-induced release of high-mobility group box 1 through activation of HDAC in human intestinal epithelial HT-29 cells.

    Science.gov (United States)

    Chi, Jin-Hua; Seo, Geom Seog; Cheon, Jae Hee; Lee, Sung Hee

    2017-02-05

    The suppression of pro-inflammatory cytokine-induced inflammation responses is an attractive pharmacological target for the development of therapeutic strategies for inflammatory bowel disease (IBD). In the present study, we evaluated the anti-inflammatory properties of flavonoid isoliquiritigenin (ISL) in intestinal epithelial cells and determined its mechanism of action. ISL suppressed the expression of inflammatory molecules, including IL-8, IL-1β and COX-2, in TNF-α-stimulated HT-29 cells. Moreover, ISL induced activation of Nrf2 and expression of its target genes, such as HO-1 and NQO1. ISL also inhibited the TNF-α-induced NF-κB activation in HT-29 cells. High-mobility group box 1 (HMGB1), which is one of the critical mediators of inflammation, is actively secreted from inflammatory cytokine-stimulated immune or non-immune cells. ISL inhibited HMGB1 secretion by preventing TNF-α-stimulated HMGB1 relocation, whereas the RNA and protein expression levels of cellular HMGB1 did not change in response to TNF-α or ISL. Moreover, we found that HMGB1 acetylation was associated with HMGB1 translocation to the cytoplasm and the extracellular release in TNF-α-stimulated HT-29 cells; however, ISL significantly decreased the amount of acetylated HMGB1 in both the cytoplasm and extracellular space of HT-29 cells. Histone deacetylase (HDAC) inhibition by Scriptaid abrogated ISL-induced HDAC activity and reversed the ISL-mediated decrease in acetylated HMGB1 release in TNF-α-stimulated HT-29 cells, suggesting that, at least in TNF-α-stimulated HT-29 cells, ISL suppresses acetylated HMGB1 release via the induction of HDAC activity. Together, the current results suggest that inhibition of HMGB1 release via the induction of HDAC activity using ISL may be a promising therapeutic intervention for IBD.

  5. A high throughput screening assay to screen for CYP2E1 metabolism and inhibition using a fluorogenic vivid p450 substrate.

    Science.gov (United States)

    Marks, Bryan D; Smith, Ronald W; Braun, Heidi A; Goossens, Tony A; Christenson, Marie; Ozers, Mary S; Lebakken, Connie S; Trubetskoy, Olga V

    2002-11-01

    Large-scale screening of multiple compound libraries and combinatorial libraries for pharmacological activity is one of the novel approaches of the modern drug discovery process. The application of isozyme-specific high-throughput screening (HTS) assays for characterizing the interactions of potential drug candidates with major human drug-metabolizing cytochrome p450 enzymes (p450s) is newly becoming an essential part of this process. Fluorescence-based HTS assays have been successfully employed for in vitro assessment of drug-drug interactions and enzyme inhibition with several p450 isoforms, including CYP3A4, CYP2D6, CYP2C9, and CYP2C19. Here we describe a fluorescence-based HTS assay for detecting drug metabolism and inhibition with human CYP2E1. CYP2E1 plays an important role in the metabolism of several drugs, many solvents, and toxins and therefore has been repeatedly linked to numerous pathologies, including cancer, liver and kidney toxicity, diabetes, and alcoholism. The assay is based on the ability of a drug to compete with the fluorogenic Vivid CYP2E1 Blue Substrate for CYP2E1 metabolism and thus enables rapid screening of lead molecules for their inhibitory potential. We have used this assay to screen a panel of drugs and compounds for their effects on CYP2E1 metabolism and inhibition. Our results demonstrate the assay's usefulness in identifying CYP2E1 substrates and inhibitors and in enabling in-depth characterization of their interactions with the CYP2E1 isozyme. We also present detailed characteristics of the assay, including its dynamic range and Z'-factor values, which indicate that this robust assay is well suited for kinetic and inhibition studies in HTS formats.

  6. SIRT4 overexpression protects against diabetic nephropathy by inhibiting podocyte apoptosis

    Science.gov (United States)

    Shi, Jian-Xia; Wang, Qi-Jin; Li, Hui; Huang, Qin

    2017-01-01

    Diabetic nephropathy is a diabetic complication associated with capillary damage and increased mortality. Sirtuin 4 (SIRT4) plays an important role in mitochondrial function and the pathogenesis of metabolic diseases, including aging kidneys. The aim of the present study was to investigate the association between SIRT4 and diabetic nephropathy in a glucose-induced mouse podocyte model. A CCK-8 assay showed that glucose simulation significantly inhibited podocyte proliferation in a time- and concentration-dependent manner. Reverse transcription-quantitative polymerase chain reaction and western blot analysis showed that the mRNA and protein levels of SIRT4 were notably decreased in a concentration-dependent manner in glucose-simulated podocytes. However, SIRT4 overexpression increased proliferation and suppressed apoptosis, which was accompanied by increases in mitochondrial membrane potential and reduced production of reactive oxygen species (ROS). Notably, SIRT4 overexpression downregulated the expression of apoptosis-related proteins NOX1, Bax and phosphorylated p38 and upregulated the expression of Bcl-2 in glucose-simulated podocytes. In addition, SIRT4 overexpression significantly attenuated the inflammatory response, indicated by reductions in the levels of TNF-α, IL-1β and IL-6. These results demonstrate for the first time that the overexpression of SIRT4 prevents glucose-induced podocyte apoptosis and ROS production and suggest that podocyte apoptosis represents an early pathological mechanism leading to diabetic nephropathy. PMID:28123512

  7. Assessment of constituents in Allium by multivariate data analysis, high-resolution α-glucosidase inhibition assay and HPLC-SPE-NMR

    DEFF Research Database (Denmark)

    Schmidt, Jeppe Secher; Nyberg, Nils; Stærk, Dan

    2014-01-01

    Bulbs and leaves of 35 Allium species and cultivars bought or collected in 2010–2012 were investigated with multivariate data analysis, high-resolution α-glucosidase inhibition assays and HPLC-HRMS-SPE-NMR with the aim of exploring the potential of Allium as a future functional food for management...... analytes with α-glucosidase inhibitory activity, and subsequent HPLC-HRMS-SPE-NMR experiments allowed identification of these as N-p-coumaroyloctopamine, N-p-coumaroyltyramine, and quercetin. The distribution of these three compounds was mapped for all samples by HPLC-ESI-HRMS. Unsupervised principal...

  8. Chlorpromazine, haloperidol, metoclopramide and domperidone release prolactin through dopamine antagonism at low concentrations but paradoxically inhibit prolactin release at high concentrations.

    Science.gov (United States)

    Besser, G. M.; Delitala, G.; Grossman, A.; Stubbs, W. A.; Yeo, T.

    1980-01-01

    1. The effects of chlorpromazine, haloperidol, metoclopramide and domperidone on the release of prolactin from perfused columns of dispersed rat anterior pituitary cells were studied. 2. Chlorpromazine, haloperidol, metoclopramide and domperidone antagonized the dopamine-mediated inhibition of prolactin release at low concentrations. 3. Each dopamine antagonist displaced the dose-response curve for dopamine-induced suppression of prolactin release to the right in a parallel manner. 4. At higher concentrations, the four drugs became less effective as dopamine antagonists. 5. At high concentrations in the absence of dopamine, chlorpromazine, haloperidol, metoclopramide and domperidone paradoxically suppressed prolactin secretion by an unknown mechanism. PMID:6110459

  9. 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.

  10. Epigenetic siRNA and Chemical Screens Identify SETD8 Inhibition as a Therapeutic Strategy for p53 Activation in High-Risk Neuroblastoma.

    Science.gov (United States)

    Veschi, Veronica; Liu, Zhihui; Voss, Ty C; Ozbun, Laurent; Gryder, Berkley; Yan, Chunhua; Hu, Ying; Ma, Anqi; Jin, Jian; Mazur, Sharlyn J; Lam, Norris; Souza, Barbara K; Giannini, Giuseppe; Hager, Gordon L; Arrowsmith, Cheryl H; Khan, Javed; Appella, Ettore; Thiele, Carol J

    2017-01-09

    Given the paucity of druggable mutations in high-risk neuroblastoma (NB), we undertook chromatin-focused small interfering RNA and chemical screens to uncover epigenetic regulators critical for the differentiation block in high-risk NB. High-content Opera imaging identified 53 genes whose loss of expression led to a decrease in NB cell proliferation and 16 also induced differentiation. From these, the secondary chemical screen identified SETD8, the H4(K20me1) methyltransferase, as a druggable NB target. Functional studies revealed that SETD8 ablation rescued the pro-apoptotic and cell-cycle arrest functions of p53 by decreasing p53(K382me1), leading to activation of the p53 canonical pathway. In pre-clinical xenograft NB models, genetic or pharmacological (UNC0379) SETD8 inhibition conferred a significant survival advantage, providing evidence for SETD8 as a therapeutic target in NB. Published by Elsevier Inc.

  11. Antibody titers against swine influenza subtypes determined by the hemagglutination inhibition test are highly dependent on the strain

    DEFF Research Database (Denmark)

    Trebbien, Ramona; Nielsen, Jens; Bøtner, Anette

    In Denmark there are three circulating strains of swine influenza H1N1, H1N2 and H3N2. The H1N2 is different from the H1N2 subtypes circulating in other European countries. The Danish subtype is a reassortment between the two Danish circulating swine influenza subtypes H1N1 and H3N2. From...... a diagnostic and epidemiological point of view it is crucial to clarify whether the immunological response to one subtype protects against infection with the other subtype. The hemagglutination inhibition test (HI-test) has been used widely to determine the presence of antibodies in serum against influenza...... viruses. In the present study the HI-test was used to determine antibody response from experimental infected pigs. The aim of the study was to evaluate the antibody response against the new Danish influenza subtype H1N2 (H1N2dk) and to examine the level of crossprotection/reaction between the two...

  12. Targeted BRAF inhibition impacts survival in melanoma patients with high levels of Wnt/β-catenin signaling.

    Directory of Open Access Journals (Sweden)

    Andy J Chien

    Full Text Available Unprecedented clinical responses have been reported in advanced stage metastatic melanoma patients treated with targeted inhibitors of constitutively activated mutant BRAF, which is present in approximately half of all melanomas. We and others have previously observed an association of elevated nuclear β-catenin with improved survival in molecularly-unselected melanoma patients. This study sought to determine whether levels of Wnt/β-catenin signaling in melanoma tumors prior to treatment might predict patient responses to BRAF inhibitors (BRAFi. We performed automated quantification of β-catenin immunohistochemical expression in pretreatment BRAF-mutant tumors from 32 BRAFi-treated melanoma patients. Unexpectedly, patients with higher nuclear β-catenin in their tumors did not exhibit the survival advantage previously observed in molecularly-unselected melanoma patients who did not receive BRAFi. In cultured melanoma cells treated with long-term BRAFi, activation of Wnt/β-catenin signaling is markedly inhibited, coinciding with a loss of the enhancement of BRAFi-induced apoptosis by WNT3A observed in BRAFi-naïve cells. Together, these observations suggest that long-term treatment with BRAFi can impact the interaction between BRAF/MAPK and Wnt/β-catenin signaling to affect patient outcomes. Studies with larger patient cohorts are required to determine whether nuclear β-catenin expression correlates with clinical responses to BRAFi and to specific mechanisms of acquired resistance to BRAFi. Understanding these pathway interactions will be necessary to facilitate efforts to individualize therapies for melanoma patients.

  13. Boronic acid-modified lipid nanocapsules: a novel platform for the highly efficient inhibition of hepatitis C viral entry

    Science.gov (United States)

    Khanal, Manakamana; Barras, Alexandre; Vausselin, Thibaut; Fénéant, Lucie; Boukherroub, Rabah; Siriwardena, Aloysius; Dubuisson, Jean; Szunerits, Sabine

    2015-01-01

    The search for viral entry inhibitors that selectively target viral envelope glycoproteins has attracted increasing interest in recent years. Amongst the handful of molecules reported to show activity as hepatitis C virus (HCV) entry inhibitors are a variety of glycan-binding proteins including the lectins, cyanovirin-N (CV-N) and griffithsin. We recently demonstrated that boronic acid-modified nanoparticles are able to reduce HCV entry through a similar mechanism to that of lectins. A major obstacle to any further development of these nanostructures as viral entry inhibitors is their only moderate maximal inhibition potential. In the present study, we report that lipid nanocapsules (LNCs), surface-functionalized with amphiphilic boronic acid (BA) through their post-insertion into the semi-rigid shell of the LNCs, are indeed far superior as HCV entry inhibitors when compared with previously reported nanostructures. These 2nd generation particles (BA-LNCs) are shown to prevent HCV infection in the micromolar range (IC50 = 5.4 μM of BA moieties), whereas the corresponding BA monomers show no significant effects even at the highest analyzed concentration (20 μM). The new BA-LNCs are the most promising boronolectin-based HCV entry inhibitors reported to date and are thus observed to show great promise in the development of a pseudolectin-based therapeutic agent.The search for viral entry inhibitors that selectively target viral envelope glycoproteins has attracted increasing interest in recent years. Amongst the handful of molecules reported to show activity as hepatitis C virus (HCV) entry inhibitors are a variety of glycan-binding proteins including the lectins, cyanovirin-N (CV-N) and griffithsin. We recently demonstrated that boronic acid-modified nanoparticles are able to reduce HCV entry through a similar mechanism to that of lectins. A major obstacle to any further development of these nanostructures as viral entry inhibitors is their only moderate maximal

  14. Flow cytometric analysis of the inhibition of human basophil activation by histamine high dilutions – a replication study

    Directory of Open Access Journals (Sweden)

    Chantal Wälchli

    2012-09-01

    Full Text Available Background: Inhibition of human basophil activation by highly diluted histamine was reported to be a reliable experimental model to examine biological effects of high dilutions. However, independent replications did not always yield concordant results. Aims: We aimed at performing an independent replication of a former study [1] using rigorously controlled experimental conditions to minimise confounding factors. Materials and Methods: In 20 independent experiments, human basophils were treated with highly diluted histamine (15cH, 16cH, corresponding to 10-30-10-32 M prior to activation by fMLP (formyl-methionyl-leucyl-phenylalanine peptide. Controls were treated with analogously diluted water (15cH, 16cH. The dilutions were prepared freshly for each experiment in deionised water by successive steps of centesimal dilution and agitation (10 s vortex at high speed. Highly diluted samples were blinded and randomised. All samples were set in triplicates. Activated basophils were determined by flow cytometry using anti-CD203c. 20 independent systematic negative control (SNC experiments were carried out to investigate possible systematic errors. Results: No difference in basophil activation was observed between the highly diluted histamine samples and the highly diluted water controls. There was no evidence for a blood donor specificity of the results. The SNC experiments demonstrated the stability of the test system. Experimental variability within and between experiments was slightly reduced for the highly diluted histamine samples. Discussion: This study was designed as an independent reproduction of a former study [1]. Though we strictly adopted the experimental procedure described in [1], our results do not confirm the large inhibitory effects observed for histamine 15cH and 16cH. This lack of reproducibility might be due to minor differences in the experimental design, such as blinding and randomising of the samples, which we chose to

  15. Development of a high-affinity peptide that prevents phospholemman (PLM) inhibition of the sodium/calcium exchanger 1 (NCX1).

    Science.gov (United States)

    Wanichawan, Pimthanya; Hodne, Kjetil; Hafver, Tandekile Lubelwana; Lunde, Marianne; Martinsen, Marita; Louch, William Edward; Sejersted, Ole Mathias; Carlson, Cathrine Rein

    2016-08-01

    NCX1 (Na(+)/Ca(2+) exchanger 1) is an important regulator of intracellular Ca(2+) and a potential therapeutic target for brain ischaemia and for diastolic heart failure with preserved ejection fraction. PLM (phospholemman), a substrate for protein kinases A and C, has been suggested to regulate NCX1 activity. However, although several studies have demonstrated that binding of phosphorylated PLM (pSer(68)-PLM) leads to NCX1 inhibition, other studies have failed to demonstrate a functional interaction of these proteins. In the present study, we aimed to analyse the biological function of the pSer(68)-PLM-NCX1 interaction by developing high-affinity blocking peptides. PLM was observed to co-fractionate and co-immunoprecipitate with NCX1 in rat left ventricle, and in co-transfected HEK (human embryonic kidney)-293 cells. For the first time, the NCX1-PLM interaction was also demonstrated in the brain. PLM binding sites on NCX1 were mapped to two regions by peptide array assays, containing the previously reported PASKT and QKHPD motifs. Conversely, the two NCX1 regions bound identical sequences in the cytoplasmic domain of PLM, suggesting that NCX1-PASKT and NCX1-QKHPD might bind to each PLM monomer. Using two-dimensional peptide arrays of the native NCX1 sequence KHPDKEIEQLIELANYQVLS revealed that double substitution of tyrosine for positions 1 and 4 (K1Y and D4Y) enhanced pSer(68)-PLM binding 8-fold. The optimized peptide blocked binding of NCX1-PASKT and NCX1-QKHPD to PLM and reversed PLM(S68D) inhibition of NCX1 activity (both forward and reverse mode) in HEK-293 cells. Altogether our data indicate that PLM interacts directly with NCX1 and inhibits NCX1 activity when phosphorylated at Ser(68).

  16. G-patch domain containing 2, a gene highly expressed in testes, inhibits nuclear factor-κB and cell proliferation.

    Science.gov (United States)

    Hu, Fen; Gou, Lixia; Liu, Qing; Zhang, Wendian; Luo, Mengmeng;