• 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 Nutrition and Health
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• v.32 no.3
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• pp.318-326
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• 1999

Apoptotic cell death, characterized by DNA fragmentation and morphological changes, has previously been shown to occur in vascular endothelial cells cultured with hydrogen peroxide. The present study examined the induction of apoptosis by hydrogen peroxide and whether pyruvate, a key glycolytic intermediate and $\alpha$-keto-monocarboxylate, can inhibit the apoptotic effects in bovine pulmonary artery endothelial cells(BPAECs). Culture with 500uM hydrogen peroxide resulted in 30% cell death and induced morphological changes and DNA fragmentation. Cell injury was inhibited by the treatment with pyruvate. Pyruvate(0.1-5.0mM), and cell viability increased in a dose-dependent manner. In the presence of pyruvate(10~20mM), the viability was improved to over 95%. In contrast, treatment with lactate, a reduced form of phyuvate, did not protect against cell death oxidative stress-induced loss of viability and apoptosis was examined with $\alpha$-cyano-3-hydroxycinnarmate(COHC) as a selective mitochondrial monocarboxylate transport blocker. Incubation with COHC(500uM) did not significantly affect cell viability in the presence of hydrogen peroxide. The cytoprotection by pyruvate(3mM)against hydrogen peroxide stress was abolished by COHC. This indicates that the cytoprotection by pyruvate against oxidative stress in endothelial cells is mediated, at least in part, by mitochondrial pyruvate uptake and hence endothelial enerygetics. However, cytosolic mechanisms related, at least in part, by mitochondrial pyruvate uptake and hence endothelial energetics. However, cytosolic mechanisms related to the glutathione system may also contribute. The results suggest that pyruvate has therapeutic potential in the treatment of oxidative stress-induced cytotoxicity associated with increased apoptosis.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.6
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• pp.431-436
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• 2009

The role of apurinic/apyrimidinic endonuclease1/redox factor-1 (Ref-1) on the lead (Pb)-induced cellular response was investigated in the cultured endothelial cells. Pb caused progressive cellular death in endothelial cells, which occurred in a concentration- and time-dependent manner. However, Ref-1 overexpression with AdRef-1 significantly inhibited Pb-induced cell death in the endothelial cells. Also the overexpression of Ref-1 significantly suppressed Pb-induced superoxide and hydrogen peroxide elevation in the endothelial cells. Pb exposure induced the downregulation of catalase, it was inhibited by the Ref-1 overexpression in the endothelial cells. Taken together, our data suggests that the overexpression of Ref-1 inhibited Pb-induced cell death via the upregulation of catalase in the cultured endothelial cells.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.2
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• pp.65-71
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• 2003

Increasing evidences suggest that ischemia-induced vascular damage is an integral step in the cascade of the cellular and molecular events initiated by cerebral ischemia. In the present study, employing a mouse brain endothelioma-derived cell line, bEnd.3, and oxygen-glucose deprivation (OGD) as an in vitro stroke model, the role of nuclear factor kappa B (NF-${\kappa}B$) activation during ischemic injury was investigated. OGD was found to activate NF-${\kappa}B$ and to induce bEnd.3 cell death in a time-dependent manner. OGD phosphorylated neither 32 Ser nor 42 Tyr of $I{\kappa}B{\alpha}$. OGD did not change the amount of $I{\kappa}B{\alpha}$. The extents of OGD-induced cell death after 8 h, 10 h, 12 h and 14 h of OGD were 10%, 35%, 60% and 85%, respectively. Reperfusion following OGD did not cause additional cell death, indicating no reperfusion injury after ischemic insult in cerebral endothelial cells. Three known as NF-${\kappa}B$ inhibitors, including pyrrolidine dithiocarbamate (PDTC) plus zinc, aspirin and caffeic acid phenethyl ester (CAPE), inhibited OGD-induced NF-${\kappa}B$ activation and increased OGD-induced bEnd.3 cell death in a dose dependent manner. There were no changes in the protein levels of bcl-2, bax and p53 which are modulated by NF-${\kappa}B$ activity. These results suggest that NF-${\kappa}B$ activation might be a protective mechanism for OGD-induced cell death in bEnd.3.

• Molecules and Cells
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• v.41 no.11
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• pp.964-970
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• 2018

Atherosclerosis preferentially involves in prone area of low and disturbed blood flow while steady and high levels of laminar blood flow are relatively protected from atherosclerosis. Disturbed flow induces endoplasmic reticulum (ER) stress and the unfolded protein response (UPR). ER stress is caused under stress that disturbs the processing and folding of proteins resulting in the accumulation of misfolded proteins in the ER and activation of the UPR. Prolonged or severe UPR leads to activate apoptotic signaling. Recent studies have indicated that disturbed flow significantly up-regulated $p-ATF6{\alpha}$, $p-IRE1{\alpha}$, and its target spliced XBP-1. However, the role of laminar flow in ER stress-mediated endothelial apoptosis has not been reported yet. The present study thus investigated the role of laminar flow in ER stress-dependent endothelial cell death. The results demonstrated that laminar flow protects ER stress-induced cleavage forms of PARP-1 and caspase-3. Also, laminar flow inhibits ER stress-induced $p-eIF2{\alpha}$, ATF4, CHOP, spliced XBP-1, ATF6 and JNK pathway; these effects are abrogated by pharmacological inhibition of PI3K with wortmannin. Finally, nitric oxide affects thapsigargin-induced cell death in response to laminar flow but not UPR. Taken together, these findings indicate that laminar flow inhibits UPR and ER stress-induced endothelial cell death via PI3K/Akt pathway.

• Archives of Pharmacal Research
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• v.29 no.1
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• pp.1-15
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• 2006

Vascular endothelial cell injury or dysfunction has been implicated in the onset and' progression of cardiovascular diseases including atherosclerosis. A number of previous studies have demonstrated that the pro-oxidative and pro-inflammatory pathways within vascular endothelium play an important role in the initiation and progression of atherosclerosis, Recent evidence has provided compelling evidence to indicate that interleukin-4 (IL-4) can induce proc inflammatory environment via oxidative stress-mediated up-regulation of inflammatory mediators such as cytokine, chemokine, and adhesion molecules in vascular endothelial cells. In addition, apoptotic cell death within vascular endothelium has been hypothesized to be involved in the development of atherosclerosis. Emerging evidence has demonstrated that IL-4 can induce apoptosis of human vascular endothelial cells through the caspase-3-dependent pathway, suggesting that IL-4 can increase endothelial cell turnover by accelerated apoptosis, the event which may cause the dysfunction of the vascular endothelium. These studies will have a high probability of revealing new directions that lead to the development of clinical strategies toward the prevention and/or treatment for individuals with inflammatory vascular diseases including atherosclerosis.

• Journal of Nutrition and Health
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• v.39 no.4
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• pp.357-365
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• 2006

DHA, one of w-3 fatty acids, modulates cell growth or death though the changes of apoptotic signaling in human endothelial ECV304 cells. We investigated the effects of DHA on the changes of apoptotic signaling in human vascular endothelial ECV304 cells using lipid peroxidation (LPO) metabolites. LPO could be originated by dietary polyunsaturated fatty acids such as linoleic acid(LA), arachidonic acid(AA) and docosahexaenoic acid (DHA). DHA caused cell death of ECV304 cells compared to LA, AA or control as evidenced by changes in cell morphology and MTT assay. LPO levels was significantly elevated by 10 fold in DHA-treated ECV 304 cells and caspase-3 activity was increased by DHA corresponding to increasing incubation times compared to control. One of reasons of the cell death in DHA-treated ECV304 cells could be expected that caspase activity, marker for mitochondrial damages, might be triggered by the increasing LPO levels. Our results strongly indicated that DHA induced LPO production has an important role on apoptotic signaling pathway in ECV304 cells. LPO production in endothelial cells which was metabolized by oxidation of dietary PUFA, might be one of risk factors in the initial progression of atherosclerosis.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.1
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• pp.11-18
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• 1999

Nuclear factor $_{\kappa}B\;(NF-_{\kappa}B)$ activation is modulated by various protein kinases. Activation of $NF-_{\kappa}B$ is known to be important in the regulation of cell viability. The present study investigated the effect of inhibitors of protein tyrosine kinase (PTK), protein kinase C (PKC) and protein kinase A (PKA) on $NF-_{\kappa}B$ activity and the viability of bovine cerebral endothelial cells (BCECs). In serum-deprivation-induced BCEC death, low doses of $TNF{\alpha}$ showed a protective effect. $TNF{\alpha}$ induced $NF-_{\kappa}B$ activation within 4 h in serum-deprivation. PTK inhibitors (herbimycin A and genistein) and PKC inhibitor (calphostin C) prevented $NF-_{\kappa}B$ activation stimulated by $TNF{\alpha}.$ Likewise, these inhibitors prevented the protective effect of $TNF{\alpha}.$ In contrast to $TNF{\alpha}-stimulated\;NF-_{\kappa}B$ activity, basal $NF-_{\kappa}B$ activity of BCECs in media containing serum was suppressed only by calphostin C, but not by herbimycin A. As well BCEC death was also induced only by calphostin C in serum-condition. H 89, a PKA inhibitor, did not affect the basal and $TNF{\alpha}-stimulated\;NF-_{\kappa}B$ activities and the protective effect of $TNF{\alpha}$ on cell death. These data suggest that modulation of $NF-_{\kappa}B$ activation could be a possible mechanism for regulating cell viability by protein kinases in BCECs.

• BMB Reports
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• v.38 no.4
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• pp.447-456
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• 2005

TNF-$\alpha$ plays a pivotal role in inflammation processes which are mainly regulated by endothelial cells. While TNF-$\alpha$ induces apoptosis of several cell types like tumor cells, endothelial cells are resistant to TNFa mediated cell death. The cytotoxic effects of TNF-$\alpha$ on most cells are only evident if RNA or protein synthesis is inhibited, suggesting that de novo RNA or protein synthesis protect cells from TNF-$\alpha$ cytotoxicity, presumably by NF-${\kappa}B$ mediated induction of protective genes. However, the cytoprotective genes involved in NF-${\kappa}B$ dependent endothelial cell survival have not been sufficiently identified. In the present study, the suppression subtractive hybridization (SSH) method was employed to identify rarely transcribed TNF-$\alpha$ inducible genes in human arterial endothelial cells related to cell survival and cell cycle. The TNF-$\alpha$-induced expression of the RNA binding protein $p54^{nrb}$ and the 14-3-3 protein HS1 as shown here for the first time may contribute to the TNF-$\alpha$ mediated cell protection of endothelial cells. These genes have been shown to play pivotal roles in cell survival and cell cycle control in different experimental settings. The concerted expression of these genes together with other genes related to cell protection and cell cycle like DnaJ, $p21^{cip1}$ and the ubiquitin activating enzyme E1 demonstrates the identification of new genes in the context of TNF-$\alpha$ induced gene expression patterns mediating the prosurvival effect of TNF-$\alpha$ in endothelial cells.

• BMB Reports
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• v.39 no.1
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• pp.97-104
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• 2006

Endostatin is a tumor-derived angiogenesis inhibitor, and the endogenous 20 kDa carboxyl-terminal fragment of collagen XVIII. In addition to inhibiting angiogenesis, endostatin inhibits tumor growth and the induction of apoptosis in several endothelial cell types. However, the mechanisms that regulate endostatin-induced apoptotic cell death are unclear. Here, we investigated apoptotic cell death and the underlying regulatory mechanisms elicited of endostatin in human umbilical vein endothelial cells (HUVECs). Endostatin was found to induce typical apoptotic features, such as, chromatin condensation and DNA fragmentation in these cells. Thus, as the phosphoinositide 3-OH kinase (PI3K)/protein kinase B (PKB) signaling pathway has been shown to prevent apoptosis in various cell types, we investigated whether this pathway could protect cells against endostatin induced apoptosis. It was found that the inhibition of PI3K/PKB significantly increased endostatin-induced apoptosis, and that endostatin-induced cell death is physiologically linked to PKB-mediated cell survival through caspase-8.