• 대한의생명과학회지
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• 제20권1호
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• pp.14-24
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• 2014

Hypoxia is one of the main reasons for islet apoptosis after transplantation as well as during isolation. In this study, we attempted to determine the potential usefulness of NF-${\kappa}B$ inhibitor for suppression of hypoxia-induced ${\beta}$-cell apoptosis as well as the relationship between IP-10 induction and ${\beta}$-cell apoptosis in hypoxia. To accomplish this, we cultured the mouse pancreatic ${\beta}$-cell line MIN6 in hypoxia (1% $O_2$). Among several examined chemokines, only IP-10 mRNA expression was induced under hypoxia, and this induced IP-10 expression was due to NF-${\kappa}B$ activity. Since a previous study suggested that IP-10 mediates ${\beta}$-cell apoptosis, we measured hypoxia-induced IP-10 protein and examined the effect of anti-IP-10 neutralizing Ab on hypoxia-induced ${\beta}$-cell apoptosis. However, IP-10 protein was not detected, and anti-IP-10 neutralizing Ab did not rescue hypoxia-induced MIN6 apoptosis, indicating that there is no relationship between hypoxia-induced IP-10 mRNA expression and hypoxia-induced ${\beta}$-cell apoptosis. Since it was still not clear if NF-${\kappa}B$ functions as an apoptotic or anti-apoptotic mediator in hypoxia-induced ${\beta}$-cell apoptosis, we examined possible involvement of NF-${\kappa}B$ in hypoxia-induced ${\beta}$-cell apoptosis. Treatment with 1 ${\mu}M$ NF-${\kappa}B$ inhibitor suppressed hypoxiainduced apoptosis by more than 50%, while 10 ${\mu}M$ AP-1 or 4 ${\mu}M$ NF-AT inhibitor did not, indicating involvement of NF-${\kappa}B$ in hypoxia-induced ${\beta}$-cell apoptosis. Overall, these results suggest that IP-10 is not involved in hypoxia-induced ${\beta}$-cell apoptosis, and that NF-${\kappa}B$ inhibitor can be useful for ameliorating hypoxia-induced ${\beta}$-cell apoptosis.

• 대한의생명과학회지
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• 제11권4호
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• pp.441-446
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• 2005

The molecular mechanism of ischemia/reperfusion injury remains unclear. Reactive oxygen species (ROS) are implicated in cell death caused by ischemia/reperfusion in vivo or hypoxia in vitro. Poly (ADP-ribose) polymerase (PARP) activation has been reported to be involved in hydrogen peroxide-induced cell death in renal epithelial cells. This study was therefore undertaken to evaluate the role of P ARP activation in chemical hypoxia in opossum kidney (OK) cells. Chemical hypoxia was induced by incubating cells with antimycin A, an inhibitor of mitochondrial electron transport. Exposure of OK cells to chemical hypoxia resulted in a time-dependent cell death. In OK cells subjected to chemical hypoxia, the generation of ROS was increased, and this increase was prevented by the $H_2O_2$ scavenger catalase. Chemical hypoxia increased P ARP activity and chemical hypoxia-induced cell death was prevented by the inhibitor of PARP activation 3-aminobenzamide. Catalase prevented OK cell death induced by chemical hypoxia. $H_2O_2$ caused PARP activation and $H_2O_2-induced$ cell death was prevented by 3-aminobenzamide. Taken together, these results indicate that chemical hypoxia-induced cell injury is mediated by PARP activation through H202 generation in renal epithelial cells.

• 대한의생명과학회지
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• 제10권4호
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• pp.341-346
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• 2004

Tumor necrosis factor-α (TNF-α) or its mRNA expression are increased in acute nephrosis of various types including ischemia/reperfusion injury. This study was undertaken to determine whether pentoxifylline (PTX), an inhibitor of TNF-α production, provides a protective effect against hypoxia-induced cell injury in rabbit renal cortical slices. To induce hypoxia-induced cell injury, renal cortical slices were exposed to 100% N₂ atmosphere. Control slices were exposed to 100% O₂ atmosphere. The cell injury was estimated by measuring lactate dehydrogenase (LDH) release and p-aminohippurate (PAH) uptake. Exposure of slices to hypoxia increased the LDH release in a time-dependent manner. However, when slices were exposed to hypoxia in the presence of PTX, the LDH release was decreased. The protective effect of PTX was dose-dependent over the concentrations of 0.05∼1 mM. Hypoxia did not increase lipid peroxidation, whereas an organic hydroperoxide t-butylhydroperoxide (tBHP) resulted in a significant increase in lipid peroxidation. PTX did not affect tBHP-induced lipid peroxidation. Hypoxia decreased PAH uptake, which was significantly attenuated by PTX and glycine. tBHP-induced inhibition of PAH uptake was not altered by PTX, although it was prevented by antioxidant deferoxarnine. The PAH uptake by slices in rabbits with ischemic acute renal failure was prevented by PTX pretreatment. These results suggest that PTX may exert a protective effect against hypoxia-induced cell injury and its effect may due to inhibition of the TNF-α production, but not by its antioxidant action.

• 대한한방내과학회지
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• 제40권3호
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• pp.425-442
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• 2019

Objectives: This study aimed to reveal the pharmacological properties of the newly prescribed herbal mixture, Chenmadansamgamibokhap-tang(CDBT), against hypoxia-induced neuronal cell injury (especially mouse hippocampal neuronal cell line, HT-22 cells) and their corresponding mechanisms. Methods: A cell-based in vitro experiment, in which a hypoxia condition induced neuronal cell death, was performed. Various concentrations of the CDBT were pre-treated to the HT-22 cells for 4 h before 18 h in the hypoxia chamber. The glial cell BV-2 cells were stimulated with $IFN{\gamma}$ and LSP to produce inflammatory cytokines and reactive oxygen species. When the neuronal HT-22 cells were treated with this culture solution, the drug efficacy against neuronal cell death was examined. Results: CDBT showed cytotoxicity in the normal condition of HT-22 cells at a dose of $125{\mu}g/mL$ and showed a protective effect against hypoxia-induced neuronal cell death at a dose of $31.3{\mu}g/mL$. CDBT prevented hypoxia-induced neuronal cell death in a dose-dependent manner in the HT-22 cells by regulating $HIF1{\alpha}$ and cell death signaling. CDBT prevented neuronal cell death signals and DNA fragmentation due to the hypoxia condition. CDBT significantly reduced cellular oxidation, cell death signals, and caspase-3 activities due to microglial cell activations. Moreover, CDBT significantly ameliorated LPS-induced BV-2 cell activation and evoked cellular oxidation through the recovery of redox homeostasis. Conclusions: CDBT cam be considered as a vital therapeutic agent against neuronal cell deaths. Further studies are required to reveal the other functions of CDBT in vivo or in the clinical field.

• Biomolecules & Therapeutics
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• 제18권2호
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• pp.145-151
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• 2010

Oxygen supply into inside solid tumor is often diminished, which is called hypoxia. Many gene transcriptions were activated by hypoxia-inducible factor (HIF)-$1{\alpha}$. Here, we investigated the effect of hypoxia on paclitaxel-resistance induction in HeLa cervical tumor cells. When HeLa cells were incubated under hypoxia condition, HIF-$1{\alpha}$ level was increased. In contrast, paclitaxel-mediated tumor cell death was reduced by the incubation under hypoxia condition. Paclitaxel-mediated tumor cell death was also inhibited by treatment with DMOG, chemical HIF-$1{\alpha}$ stabilizer, in a dose-dependent manner. A significant increase in intracellular ROS level was detected by the incubation under hypoxia condition. A basal level of cell density was increased in response to 10 nM $H_2O_2$. HIF-$1{\alpha}$ level was increased by treatment with various concentration of $H_2O_2$. The increased level of HIF-$1{\alpha}$ by hypoxia was reduced by the treatment with N-acetylcysteine (NAC), a well-known ROS scavenger. Paclitaxel-mediated tumor cell death was increased by treatment with NAC. Taken together, these findings demonstrate that hypoxia could play a role in paclitaxel-resistance induction through ROS-mediated HIF-$1{\alpha}$ stabilization. These results suggest that hypoxia-induced ROS could, in part, control tumor cell death through an increase in HIF-$1{\alpha}$ level.

• 대한의생명과학회지
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• 제27권2호
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• pp.69-76
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• 2021

The aim of this study was to evaluate gamma-aminobutyric acid (GABA)-induced erythropoietin (EPO) and EPO-receptor expression in human Hep3B cells and Sprague Dawley (SD) rats during hypoxia. Expression levels of EPO, EPO-R mRNA, Janus kinase-2 (JAK-2), vascular endothelial growth factor (VEGF), hypoxia inducible factor-1 (HIF-1), and HIF-2 in response to GABA treatment were evaluated in cell lines. SD rats were randomly divided into 5 groups of 8 rats each, and GABA was orally administered; the groups were the normal control (NC), hypoxia-exposed (G0), as well as the GABA 1 mg/100 g body weight (BW) GABA treated group (G1), 5 mg/100 g BW GABA treated group (G5), and 10 mg/100 g BW GABA treated group (G10) with hypoxia. We analyzed EPO levels and red blood cell counts in rat blood and EPO gene expression in kidney tissue. EPO and VEGF mRNA levels in Hep3B cells exposed to hypoxia were significantly increased and further increased after GABA treatment. However, the expression of EPO-R and JAK-2 mRNAs were not affected by GABA, but hypoxia-induced HIF-1 and HIF-2 mRNA expression was inhibited by GABA. In the kidney tissue of rats exposed to hypoxia, the expression level of EPO mRNA was greatly increased, but levels in the GABA treatment groups significantly decreased. EPO levels in the serum showed the same significant trend, but the red blood cell counts were not significantly different. These findings demonstrate that HIF-1 and HIF-2 activation increase EPO expression in Hep3B cells exposed to hypoxia. However HIF decreased by GABA addition and VEGF increased significantly.

• Archives of Pharmacal Research
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• 제20권2호
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• pp.103-109
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• 1997

The effects of ginseng total saponins (GTS) on hypoxic damage of primary cultures of astrocytes were studied. Hypoxia was created by placing cultures in an air tight chamber that was flushed with 95% $N_2/5%CO_2$ for 15 min before being sealed. Cultures showed evidence of significant cell injury after 24 h of hypoxia (increased lactate dehydrogenase (LDH) content in the culture medium, cell swelling and decreased glutamate uptake and protein content). Addition of GTS (0.1, 0.3 mg/ml) to the cultures during the exposure to hypoxic conditions produced dose-dependent inhibition of the LDH efflux. GTS (0.1, 0.3 mg/ml) also produced significant inhibition of the increased cell volume of astrocytes measured by $[^3H]$ O-methyl-D-glucose uptake under the hypoxic conditions. Decreased glutamate uptake and protein content was inhibited by GTS. These data suggest that GTS prevents astrocytic cell injury induced by severe hypoxia in vitro.

• The Korean Journal of Physiology and Pharmacology
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• 제3권1호
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• pp.93-100
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• 1999

The present study was designed to assess the roles of $PLA_2$ activation and arachidonic acid (AA) metabolites in hypoxia-induced renal cell injury. Hypoxia increased LDH release in a dose-dependent manner in rabbit renal cortical slices, and this increase was significant after 20-min hypoxia. The hypoxia-induced LDH release was prevented by amino acids, glycine and alanine, and extracellular acidosis (pH 6.0). Buffering intracellular $Ca^{2+}$ by a chelator, but not omission of $Ca^{2+}$ in the medium produced a significant reduction in hypoxia-induced LDH release. The effect of hypoxia was blocked by $PLA_2$ inhibitors, mepacrine, butacaine, and dibucaine. A similar effect was observed by a 85-kD $cPLA_2$ inhibitor $AACOCF_3.$ AA increased hypoxia-induced LDH release, and albumin, a fatty acid absorbent, prevented the LDH release, suggesting that free fatty acids are involved in hypoxia-induced cell injury. These results suggest that $PLA_2$ activation and its metabolic products play important roles in pathogenesis of hypoxia-induced cell injury in rabbit renal cortical slices.

• Asian Pacific Journal of Cancer Prevention
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• 제15권19호
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• pp.8251-8257
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• 2014

Apoptosis is one of main types of neural cell death and is reversible and is a major target of therapeutic interventions. However, detailed apoptotic cascades still need to be recognized. In present study, we determined the promotion of HIF-$1{\alpha}$ and survivin in brain samples of a mouse model of hypoxic-ischemia and in neuroblastoma SH-SY5Y cells post hypoxia treatment. Then gain-of-function and loss-of-function strategies were adopted to manipulate the HIF-$1{\alpha}$ in SH-SY5Y cells, and hypoxia-induced survivin upregulation and cell apoptosis were determined. Results demonstrated that the HIF-$1{\alpha}$ and survivin were significantly promoted in a mouse model of hypoxic-ischemia or in SH-SY5Y cells post hypoxia in vitro. Manually upregulated HIF-$1{\alpha}$ could promote the hypoxia-induced survivin upregulation and improve the hypoxia-induced SH-SY5Y cell apoptosis. On the other hand, the HIF-$1{\alpha}$ knockdown by RNAi reduced the hypoxia-induced survivin upregulation and cell apoptosis. Therefore, the present study confirmed the protective role of HIF-$1{\alpha}$ and survivin in the hypoxia-induced SH-SY5Y cell apoptosis, and the survivin upregulation by hypoxia is HIF-$1{\alpha}$-dependent. Promotion of HIF-$1{\alpha}$ and survivin might be a valuable stragegy for therapeutic intervention for hypoxic-ischemic encephalopathy.

• Journal of Korean Neurosurgical Society
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• 제40권2호
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• pp.103-109
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• 2006

Objective : Activated endothelial cells mediate the cascade of reactions in response to hypoxia for adaptation to the stress. It has been suggested that hypoxia, by itself, without reperfusion, can activate the endothelial cells and initiate complex responses. In this study, we investigated whether hypoxia-induced endothelial products alter the endothelial permeability and have a direct cytotoxic effect on nerve cells. Methods : Hypoxic condition of primary human umbilical vein endothelial cells[HUVEC] was induced by $CoCl_2$ treatment in culture medium. Cell growth was evaluated by 3,4,5-dimethyl thiazole-3,5-diphenyl tetrazolium bromide [MTT] assay Hypoxia-induced products [$IL-1{\beta},\;TGF-{\beta}1,\;IFN-{\gamma},\;TNF-{\alpha}$, IL-10, IL-6, IL-8, MCP-l and VEGF] were assessed by enzyme-linked immunosorbent assay. Endothelial permeability was evaluated by Western blotting. Results : Prolonged hypoxia caused endothelial cells to secrete IL -6, IL -8, MCP-1 and VEGF. However, the levels of IL -1, IL -10, $TNF-{\alpha},\;TGF-{\beta},\;IFN-{\gamma}$ and nitric oxide remained unchanged over 48 h hypoxia. Hypoxic exposure to endothelial cells induced the time-dependent down regulation of the expression of cadherin and catenin protein. The conditioned medium taken from hypoxic HUVECs had the cytotoxic effect selectively on neuroblastoma cells, but not on astroglioma cells. Conclusion : These results suggest the possibility that endothelial cell derived cytokines or other secreted products with the increased endothelial permeability might directly contribute to nerve cell injury followed by hypoxia.