• Preventive Nutrition and Food Science
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• v.19 no.3
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• pp.170-177
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• 2014

Endothelial cell dysfunction is considered to be a major cause of vascular complications in diabetes. In the present study, we investigated the protective effect of a baechu kimchi added Ecklonia cava extract (BKE) against high glucose induced oxidative damage in human umbilical vein endothelial cells (HUVECs). Treatment with a high concentration of glucose (30 mM) induced cytotoxicity, whereas treatment with BKE protected HUVECs from high glucose induced damage; by restoring cell viability. In addition, BKE reduced lipid peroxidation, intracellular reactive oxygen species and nitric oxide levels in a dose dependent manner. Treatment with high glucose concentrations also induced the overexpression of inducible nitric oxide synthase, cyclooxygenase-2 and NF-${\kappa}B$ proteins in HUVECs, but BKE treatment significantly reduced the overexpression of these proteins. These findings indicate that BKE may be a valuable treatment against high glucose-induced oxidative stress HUVECs.

• The Korean Journal of Physiology and Pharmacology
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• v.1 no.5
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• pp.515-521
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• 1997

Endothelial cells play a central role in the inflammatory processes, and activation of nuclear factor kappa B ($NF-_{\kappa}B$) is a key component in that inflammatory processes. Previously, we reported that tumor necrosis factor alpha($TNF{\alpha}$) had protective effect of cell death induced by serum deprivation and this protection was related to $NF-_{\kappa}B$ activation. Inducible nitric oxide synthase (iNOS) is a member of the molecules which transcription is regulated mainly by $NF-_{\kappa}B$. And the role of nitric oxide (NO) generated by iNOS on cell viability is still controversial. To elucidate the mechanism of $TNF{\alpha}$ and $NF-_{\kappa}B$ activation on cell death protection, we investigate the effect of NO on the cell death induced by serum- deprivation in bovine cerebral endothelial cells in this study. Addition of $TNF{\alpha}$, which are inducer of iNOS, prevented serum-deprivation induced cell death. Increased expression of iNOS was confirmed indirectly by nitrite measurement. When selective iNOS inhibitors were treated, the protective effect of $TNF{\alpha}$ on cell death was partially blocked, suggesting that iNOS expression was involved in controlling cell death. Exogenously added NO substrate (L-arginine) and NO donors (sodium nitroprusside and S-nitroso-N-acetylpenicillamine) also inhibited the cell death induced by serum deprivation. These results suggest that NO has protective effect on bovine cerebral endothelial cell death induced by serum-deprivation and that iNOS is one of the possible target molecules by which $NF-_{\kappa}B$ exerts its cytoprotective effect.

• Journal of Life Science
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• v.24 no.2
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• pp.181-185
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• 2014

We identified SNPs (single nucleotide polymorphisms) for endothelial nitric oxide synthase (eNOS) genes in the Korean genome. eNOS is present in the vascular endothelium, platelets, and several other cell types that continuously produce modest amounts of NO. Endothelium-derived NO plays a key role in the regulation of vascular tone, and the impaired effects of NO on the cardiovascular system appear to be responsible for coronary atherosclerosis and thrombosis. In recent studies, a missense variant within exon 7 of the eNOS gene in patients with coronary spastic angina-GAG to GAT substitution, which results in the replacement of glutamic acid by aspartic acid (Glu298Asp [G894T])-has been identified and is known to be significantly associated with coronary spasm. We prepared PCR primers based on sequences in Genbank. Primers were prepared for normal and SNPs separately, as reported for other Asian countries, such as G894T. Their sequences were different only at the 3' ends so that primer extension could only by possible when base pairs between templates and primers matched. We also employed ARMS (Amplification Refractory Mutation System) technology to improve the specificity of the PCR reaction. In conclusion, we were able to demonstrate the eNOS G894A polymorphism in Korean gemone. This study should facilitate research on the cause of myocardial infarction and development on further therapy at the genetic level.

• Journal of Nutrition and Health
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• v.50 no.3
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• pp.236-245
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• 2017

Purpose: The aim of this study was to assess the effects of guava leaf extract (GLE) supplementation on antioxidant enzyme activity and expression of endothelial nitric oxide synthase (eNOS) mRNA in ovariectomized rats. Methods: All animals were randomly assigned to four groups (n = 7 for each group): non-ovariectomized control (Sham), the ovariectomized control (OVX), ovariectomy + 150 mg/kg b.w. of GLE ($OVX{\cdot}GL$), and ovariectomy + 300 mg/kg b.w. of GLE ($OVX{\cdot}GH$). Treatment groups were administered GLE for 8 weeks every day. Results: Body weight gain was significantly reduced in the $OVX{\cdot}GL$ group compared with the OVX group (p < 0.05). The level of serum $17{\beta}$-estradiol (E2) was significantly lower in the OVX groups than the Sham group (p < 0.05). Serum triglyceride (TG) and HDL-cholesterol levels were not significantly different between all groups. However, serum total cholesterol (TC) level was significantly reduced in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Serum free fatty acid (FFA) level and liver TG level were significantly reduced in both $OVX{\cdot}GL$ and $OVX{\cdot}GH$ groups compared with the OVX group (p < 0.05). Furthermore, serum glutathione peroxidase (GPx) activity was significantly elevated in the GLE groups (p < 0.05). The mRNA expression level of GPx was not affected by ovariectomy. However, administration of GLE resulted in significantly increased nuclear factor erythroid 2-related factor (Nrf2) and catalase (CAT) mRNA expression levels in the liver (p < 0.05). In addition, liver nitric oxide (NO) level was significantly reduced in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Expression level of endothelial nitric oxide synthase (eNOS) was significantly elevated in the $OVX{\cdot}GH$ group compared with the OVX group (p < 0.05). Conclusion: These results suggest that GLE could have protective effects in OVX rats by stimulating eNOS expression and improving the antioxidant defense system.

• The Korean Journal of Pharmacology
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• v.30 no.3
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• pp.337-342
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• 1994

It is well known that angiotensin converting enzyme inhibitors(ACEIs) increase endothelium-dependent relaxation in aortic strips of spontaneously hypertensive rats(SHR) and this increase in relaxation may be due to altered endothelial nitric oxide breakdown. But there are few studies on the effect of the angiotensin II receptor blocker on the nitric oxide-mediated relaxation. So we attempted to investigate the effect of angiotensin II receptor blocker on the nitric oxide-dependent relaxation in isolated aorta of SHR. Two week-treatment of losartan (30 mg/kg/day) increased the acetylcholine$(10^{-9}\;to\;10^{-5}\;M)$-and histamine$(10^{-8}\;to\;10^{-4}\;M)$-induced relaxation in endothelium intact strips but 90 minutes-treatment of losartan $(10^{-4}\;M)$ showed no increase in relaxation. The phenylephrine $(10^{-7}\;M)$-induced contraction, repeated every 2 hours, was diminished gradually following lipopolysaccharide (LPS)-treatment $(100\;{\mu}g/ml)$ but there was no significant difference in enalapril- and losartan-treated group compared with control group. These results suggest that activity of the endothelial constitutive NO synthase may be changed by chronic treatment of angiotensin II receptor blockers and ACEIs but angiotensin II antagonist and ACEI have no effect on the inducible NO synthase activity in the isolated aorta of SHR

• Journal of Korean Neurosurgical Society
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• v.38 no.3
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• pp.221-226
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• 2005

Objective : Reactive oxygen metabolites and polymorphonuclear leukocytes have been implicated in the pathophysiology of reperfusion injury. The mechanisms involved in superoxide-mediated leukocyte adherence remain unclear, however, nitric oxide[NO] may contribute to this response. The present study is undertaken to elucidate mechamisms controlling NO based mechanisms that regulated leukocyte-endothelial interactions in the cerebral vasculature after global cerebral ischemia and reperfusion. Methods : Pial venular leukocyte adherence of anesthetized newborn piglets was quantified by in situ fluorescence videomicroscopy through closed cranial windows during basal conditions and during 2hours of reperfusion after global ischemia induced by 9minutes of asphyxia. Nitric oxide synthase[NOS] was inhibited by local window superfusion of L-nitroarginine[NA]; superfusion of sodium nitroprusside[SNP] was used to donate NO. Results : The mean number of adherent leukocytes to cerebral venules in the 9minutes asphyxia and 2hours reperfusion group were $161{\pm}19$ compared with $13{\pm}4$ in the nonasphyxial group. Superfusion of L-NA through the cranial window for 2hours resulted in leukocyte adherence similar to that observed during the initial 2hours of reperfusion after asphyxia. Leukocyte adherence was not additionally increased in asphyxic animal treated with L-NA. SNP inhibited asphyxia induced leukocyte adherence back to control levels. Conclusions : Nitric oxide inhibits leukocyte adherence to cerebral venules during the initial hours of reperfusion after asphyxia, and that NO supplementation inhibit asphyxia induced leukocyte adherence back to control levels. These results indicate that NO is an important factor in ischemia-reperfusion induced leukocyte adherence.

• Biomolecules & Therapeutics
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• v.28 no.6
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• pp.549-560
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• 2020

Although DNA damage responses (DDRs) are reported to be involved in nitric oxide (NO) production in response to genotoxic stresses, the precise mechanism of DDR-mediated NO production has not been fully understood. Using a genotoxic agent aphidicolin, we investigated how DDRs regulate NO production in bovine aortic endothelial cells. Prolonged (over 24 h) treatment with aphidicolin increased NO production and endothelial NO synthase (eNOS) protein expression, which was accompanied by increased eNOS dimer/monomer ratio, tetrahydrobiopterin levels, and eNOS mRNA expression. A promoter assay using 5'-serially deleted eNOS promoters revealed that Tax-responsive element site, located at -962 to -873 of the eNOS promoter, was responsible for aphidicolin-stimulated eNOS gene expression. Aphidicolin increased CREB activity and ectopic expression of dominant-negative inhibitor of CREB, A-CREB, repressed the stimulatory effects of aphidicolin on eNOS gene expression and its promoter activity. Co-treatment with LY294002 decreased the aphidicolin-stimulated increase in p-CREB-Ser¹³³ level, eNOS expression, and NO production. Furthermore, ectopic expression of dominant-negative Akt construct attenuated aphidicolin-stimulated NO production. Aphidicolin increased p-ATM-Ser¹⁹⁸¹ and the knockdown of ATM using siRNA attenuated all stimulatory effects of aphidicolin on p-Akt-Ser⁴⁷³, p-CREB-Ser¹³³, eNOS expression, and NO production. Additionally, these stimulatory effects of aphidicolin were similarly observed in human umbilical vein endothelial cells. Lastly, aphidicolin increased acetylcholine-induced vessel relaxation in rat aortas, which was accompanied by increased p-ATM-Ser¹⁹⁸¹, p-Akt-Ser⁴⁷³, p-CREB-Ser¹³³, and eNOS expression. In conclusion, our results demonstrate that in response to aphidicolin, activation of ATM/Akt/CREB/eNOS signaling cascade mediates increase of NO production and vessel relaxation in endothelial cells and rat aortas.

• Journal of Ginseng Research
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• v.23 no.2 s.54
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• pp.81-87
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• 1999

The effect of saponin and non-saponin of Panax Red Ginseng on the blood pressure and nitric oxide production were investigated in the conscious free moving one-kidney, one-clip Goldbaltt hypertensive (lK, 1C-GBH) rats. Mean blood pressure in the control and lK, 1C-GBH rats was decreased by the administration of ginseng saponin (100 mg/kg, i.v.). The hypotensive effect induced by ginseng saponin was reached maximum at 2-4 minutes and was slowly recovered to the initial level of blood pressure. Also ginseng saponin induced reflex tachycardia in the conscious both rats. Contrast to the response induced by ginseng saponin, hypotensive effect induced by non-saponin of panax ginseng is minimal. Plasma nitric oxide concentration was increased by the treatment of ginseng saponin (100 mg/kg, i.p for 5 days) in both rats. It has been shown by western blotting that the expression level of the protein for endothelial nitric oxide synthase (eNOS) in the aorta of rats was not increased by the treatment of ginseng saponin (100 mg/kg, i.p). However, eNOS activity in aortic homogenates of both rats were increased by the treatment of ginseng saponins. From the above results, the hypotensive effect of saponin was greater than that of non-saponin of Panax Red Ginseng. The lowering effect of blood pressure by ginseng saponin may be due to the increase of plasma nitric oxide concentration via the increase of endothelial nitric oxide synthase activity in the renovascular hypertensive and control rats.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1997.04a
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• pp.90-90
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• 1997

Natural products, which have been used for the treatment of hypertension, diuresis and nephritis in traditional oriental medicine, were selected for the screening of nitric oxide (NO) production in endothelial cells and kidney tissues in vitro as well as in vivo by measuring the conversion of [$\^$14/C]-L-arginine to [$\^$14/C]-L-citrulline, a coproduct of the enzyme reaction with NO. Confluent monolayer of endothelial cells were used for the screening of 16 natural products. Among the natural products, Zizyphus jujuba and Codonopsis pilosula stimulated endothelial NO synthase activity. Thus, both confluent monolayer of endothelial cells and kidney homogenates (glomeruli, cortical tubules, meudllae) were treated with Zizyphus jujuba and Codonopsis pilosula (final concentration 10 $\mu\textrm{g}$/$m\ell$) and NO releases were compared with those by receptor - dependent agonists, bradykinin and ADP and receptor - independent calcium ionophore A23187 in vitro. In rat experiment, NO releases in glomeruli, cortical tubules and medullae and plasma renin activity were assessed after intraperitoneal injection of Zizyphus jujuba and Codonopsis pilosula (10 mg/kg/day for 4 days). As a result, both Zizyphus jujuba and Codonopsis pilosula significantly increased NO releases in cultured endothelial cells, kidney tissues in vitro as well as in vivo. Stimulation of NO releases by Zizyphus jujuba and Codonopsis pilosula was similar to those by receptor - dependent agonists, bradykinin and ADP and receptor - independent calcium ionophore A23187 in cultured endothelial cells. However, plasma renin activity was not influenced by these two natural products. In conclusion, stimulatory effects of Zizyphus jujuba and Codonopsis pilosula on NO release in kidney may contribute their hypotensive effects and antinephritic action possibly by increasing renal blood flow.

• Journal of Physiology & Pathology in Korean Medicine
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• v.23 no.2
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• pp.416-425
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• 2009

Angiogenesis is important for promoting cardiovascular disease, wound healing, and tissue regeneration. We here investigated the pharmacological effects of Korea red ginseng water extract (KRGE) on angiogenesis and its underlying signal mechanism. This study showed that KRGE increased in vitro proliferation, migration, and tube formation of human umbilical endothelial cells, as well as stimulated in vivo angiogenesis. KRGE-induced angiogenesis was accompanied by phosphorylation of ERK1/2, Akt, and endothelial nitric oxide synthase (eNOS) as well as an increase in NO production. Inhibition of PI3K activity by wortmannin completely inhibited KRGE-induced angiogenesis and phosphorylation of Akt, ERK1/2, and eNOS, indicating that PI3K/Akt activation is an upstream event of KRGE-mediated angiogenic pathway. The MEK inhibitor PD98059 completely blocked KRGE-induced angiogenesis and ERK phosphorylation without affecting Akt and eNOS activation. However, the eNOS inhibitor NMA effectively inhibited tube formation, but partially blocked proliferation and migration as well as ERK phosphorylation without altering Akt and eNOS activation, revealing that eNOS/NO pathway is in part involved in ERK1/2 activation. This study first demonstrated the critical involvement of both ERK1/2 and eNOS activation in KRGE-induced angiogenesis, which lie on downstream of PI3K/Akt. Thus, these results indicate that KRGE requires activation of both the PI3K/Akt-dependent ERK1/2 and eNOS signal pathways and their cross-talk for its full angiogenic activity.