scholarly journals High-glucose-induced metallothionein expression in endothelial cells: an endothelin-mediated mechanism

2001 ◽  
Vol 281 (3) ◽  
pp. C899-C907 ◽  
Author(s):  
Margarita D. Apostolova ◽  
Shali Chen ◽  
Subrata Chakrabarti ◽  
M. George Cherian

Vascular endothelial cells are constantly exposed to oxidative stress and must be protected by physiological responses. In diabetes mellitus, endothelial cell permeability is impaired and may be increased by high extracellular glucose concentrations. It has been postulated that metallothionein (MT) can protect endothelial cells from oxidative stress with its increased expression by cytokines, thrombin, and endothelin (ET)-1. In this study, we demonstrate that high glucose concentration can induce MT expression in endothelial cells through a distinct ET-dependent pathway. Exposure of human umbilical vein endothelial cells (HUVEC) to increasing concentrations of glucose resulted in a rapid dose-dependent increase in MT-2 and ET-1 mRNA expression. MT expression may be further augmented with addition of ET-1. Preincubation of the cells with the specific ETB antagonist BQ-788 blocked MT-2 mRNA expression more effectively than the ETA inhibitor TBC-11251. High glucose also increased immunoreactive MT protein expression and induced translocation of MT into the perinuclear area. Perinuclear localization of MT was related to high-glucose-induced reorganization of F-actin filaments. These results demonstrate that an increase in extracellular glucose in HUVEC can lead to a rapid dose-dependent increase in MT-2 mRNA expression and to perinuclear localization of MT protein with changes to the cytoskeleton. These effects are mediated via the ET receptor-dependent pathway.

Endocrinology ◽  
2010 ◽  
Vol 151 (10) ◽  
pp. 5030-5037 ◽  
Author(s):  
Pradeep P. Kayampilly ◽  
Brett L. Wanamaker ◽  
James A. Stewart ◽  
Carrie L. Wagner ◽  
K. M. J. Menon

Elevated levels of 5α-reduced androgens have been shown to be associated with hyperandrogenism and hyperinsulinemia, the leading causes of ovulatory dysfunction in women. 5α-Dihydrotestosterone reduces ovarian granulosa cell proliferation by inhibiting FSH-mediated mitogenic signaling pathways. The present study examined the effect of insulin on 5α-reductase, the enzyme that catalyses the conversion of androgens to their 5α-derivatives. Granulosa cells isolated from immature rat ovaries were cultured in serum-free, phenol red-free DMEM-F12 media and treated with different doses of insulin (0, 0.1, 1.0, and 10.0 μg/ml) for different time intervals up to 12 h. The expression of 5α-reductase type 1 mRNA, the predominant isoform found in granulosa cells, showed a significant (P < 0.05) increase in response to the insulin treatment up to 12 h compared with control. The catalytic activity of 5α-reductase enzyme was also stimulated in a dose-depended manner (P < 0.05). Inhibiting the Akt-dependent signaling pathway abolished the insulin-mediated increase in 5α-reductase mRNA expression, whereas inhibition of the ERK-dependent pathway had no effect. The dose-dependent increase in 5α-reductase mRNA expression as well as catalytic activity seen in response to insulin treatment was also demonstrated in the human granulosa cell line (KGN). In addition to increased mRNA expression, a dose-dependent increase in 5α-reductase protein expression in response to insulin was also seen in KGN cells, which corroborated well with that of mRNA expression. These results suggest that elevated levels of 5α-reduced androgens seen in hyperinsulinemic conditions might be explained on the basis of a stimulatory effect of insulin on 5α-reductase in granulosa cells. The elevated levels of these metabolites, in turn, might adversely affect growth and proliferation of granulosa cells, thereby impairing follicle growth and ovulation.


2007 ◽  
Vol 566 (1-3) ◽  
pp. 1-10 ◽  
Author(s):  
Hiroshi Tsuneki ◽  
Naoto Sekizaki ◽  
Takashi Suzuki ◽  
Shinjiro Kobayashi ◽  
Tsutomu Wada ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jingshang Wang ◽  
Huijun Yin ◽  
Ye Huang ◽  
Chunyu Guo ◽  
Chengdong Xia ◽  
...  

Panax quinquefolius saponin of stem and leaf (PQS), the effective parts of American ginseng, is widely used in China as a folk medicine for diabetes and cardiovascular diseases treatment. In our previous studies, we have demonstrated that PQS could improve the endothelial function of type II diabetes mellitus (T2DM) rats with high glucose fluctuation. In the present study, we investigated the protective effects of PQS against intermittent high glucose-induced oxidative damage on human umbilical vein endothelial cells (HUVECs) and the role of phosphatidylinositol 3-kinase kinase (PI3K)/Akt/GSK-3βpathway involved. Our results suggested that exposure of HUVECs to a high glucose concentration for 8 days showed a great decrease in cell viability accompanied by marked MDA content increase and SOD activity decrease. Moreover, high glucose significantly reduced the phosphorylation of Akt and GSK-3β. More importantly, these effects were even more evident in intermittent high glucose condition. PQS treatment significantly attenuated intermittent high glucose-induced oxidative damage on HUVECs and meanwhile increased cell viability and phosphorylation of Akt and GSK-3βof HUVECs. Interestingly, all these reverse effects of PQS on intermittent high glucose-cultured HUVECs were inhibited by PI3K inhibitor LY294002. These findings suggest that PQS attenuates intermittent-high-glucose-induced oxidative stress injury in HUVECs by PI3K/Akt/GSK-3βpathway.


2016 ◽  
Vol 71 (1-2) ◽  
pp. 21-28 ◽  
Author(s):  
Mi Hwa Park ◽  
Jae-Won Ju ◽  
Mihyang Kim ◽  
Ji-Sook Han

AbstractEndothelial cell dysfunction is considered a major cause of vascular complications in diabetes. In the present study, we investigated the protective effect of daidzein, a natural isoflavonoid, against high-glucose–induced oxidative damage in human umbilical vein endothelial cells (HUVECs). Treatment with a high concentration of glucose (30 mM) induced oxidative stress in the endothelial cells, against which daidzein protected the cells as demonstrated by significantly increased cell viability. In addition, lipid peroxidation, intracellular reactive oxygen species (ROS) generation, and indirect nitric oxide levels induced by the high glucose treatment were significantly reduced in the presence of daidzein (0.02–0.1 mM) in a dose-dependent manner. High glucose levels induced the overexpression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and NF-κB proteins in HUVECs, which was suppressed by treatment with 0.04 mM daidzein. These findings indicate the potential of daidzein to reduce high glucose-induced oxidative stress.


2001 ◽  
Vol 281 (3) ◽  
pp. H1364-H1371 ◽  
Author(s):  
Takatoshi Saito ◽  
Hiroshi Itoh ◽  
Tae-Hwa Chun ◽  
Yasutomo Fukunaga ◽  
Jun Yamashita ◽  
...  

To elucidate the significance of oxidative stress in the modulation of endothelial functions, we examined the effects of H2O2 on the expression of two endothelium-derived vasoactive peptides, endothelin (ET) and adrenomedullin (Am), and their interaction. H2O2 dose dependently suppressed ET secretion and ET-1 mRNA expression in bovine carotid endothelial cells (ECs). Menadion sodium bisulfate, a redox cycling drug, also decreased ET secretion in a dose-dependent manner. Catalase, a H2O2 reductase, and dl-α-tocopherol (vitamin E) significantly inhibited H2O2-induced suppression of ET secretion. Downregulation of ET-1 mRNA under oxidative stress was regulated at the transcriptional level. In contrast, H2O2increased Am secretion (and its mRNA expression) accompanied by the augmentation of cAMP production. Am, as well as 8-bromo-cAMP and forskolin decreased ET secretion in a dose-dependent fashion. Furthermore, an anti-Am monoclonal antibody that we developed abolished H2O2-induced suppression of ET secretion at 6–24 h after the addition of H2O2. H2O2 increased the intracellular Ca2+ concentration ([Ca2+]i). Moreover, treatment with ionomycin, a Ca2+ ionophore, and thapsigargin, an inhibitor of endoplasmic reticulum ATPase, decreased ET secretion dose dependently for 3 h. These results suggest that the production of ET was decreased via activation of the Am-cAMP pathway and by the elevation of [Ca2+]i under oxidative stress. These findings elucidate the coordinate expression of two local vascular hormones, ET and Am, under oxidative stress, which may protect against vascular diseases.


2016 ◽  
Vol 39 (3) ◽  
pp. 847-859 ◽  
Author(s):  
Jie Li ◽  
Junfeng Li ◽  
Tingting Wei ◽  
Junhua Li

Background/Aims: To investigate the effects of miR-137 on high glucose (HG)-induced vascular injury, and to establish the mechanism underlying these effects. Methods: Human umbilical vein endothelial cells (HUVECs) were transfected with miR-137 inhibitor or mimic, and then treated with normal or high glucose. Cell viability and apoptosis were detected by using the Cell Counting Kit-8 (CCK-8) assay and flow cytometry, respectively. Reactive oxygen species (ROS), malondialdehyde (MDA), and superoxide dismutase (SOD) were detected by fluorescent probe (DCFH-DA), thiobarbituric acid reaction, and the nitroblue tetrazolium assay, respectively. The mRNA and protein expressions of AMPKα1 were determined by qRT-PCR and Western blotting. Results: Down-regulation of miR-137 dramatically reverted HG-induced decreases in cell viability and SOD levels and increases in apoptosis, ROS and MDA levels. Moreover, bioinformatics analysis predicted that the AMPKα1 was a potential target gene of miR-137. Luciferase reporter assay demonstrated that miR-137 could directly target AMPKα1. AMPKα1 overexpression had the similar effect as miR-137 inhibition. Down-regulation of AMPKα1 in HUVECs transfected with miR-137 inhibitor partially reversed the protective effect of miR-137 inhibition on HG-induced oxidative stress in HUVECs. Conclusion: Down-regulation of miR-137 ameliorates HG-induced injury in HUVECs by overexpression of AMPKα1, leading to increasing cellular reductive reactions and decreasing oxidative stress. These results provide further evidence for protective effect of miR-137 inhibition on HG-induced vascular injury.


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