• The Journal of Internal Korean Medicine
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• v.34 no.2
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• pp.178-191
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• 2013

Objectives : In this study, we made an effort to investigate the protective mechanism of Ukgan-san (UGS) extracts on hypoxia-induced C6 glial cell death. Methods : The cell viability was assessed by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide (MMT) assay and cell morphological changes were analysed with microscope after staining with crystal violet (CV). Reactive oxygen species (ROS) formation was assessed by flow cytometer after staining with 2'7'-dichlorofluorescein diacetate (DCF-DA). We also analyzed expression of hypoxia-inducible factor-1 alpha (HIF-$1{\alpha}$) and p53, processing of procaspase-3 and procyclic acidic repetitive protein (PARP) by western blot method. Results : We estimated the elevated cell viability by UGS extract on $CoCl_2$-induced C6 glial cells. UGS attenuated $CoCl_2$-induced ROS formation in C6 glial cells and also showed a protective activity compared to antioxidants and exhibited abrogation of LDH-released by $CoCl_2$. UGS suppressed the typical apoptotic cell death markers, caspase-3 and PARP activation. UGS inhibited $CoCl_2$-induced HIF-1${\alpha}$ expression which is known as a major regulator for hypoxia-induced cell death, and suppressed p53 expression. Conclusions : These results suggest that UGS extract contains protective constituents for hypoxia-induced C6 glial cell death.

• Journal of Life Science
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• v.23 no.10
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• pp.1183-1191
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• 2013

Human apurinic/apyrimidinic endonuclease (APEX-1) is a multifunctional protein that is capable of repairing abasic sites and single-strand breaks in damaged DNA. In addition, it serves as a redox-modifying factor for a number of transcription factors. Identifying the transcriptional targets of APEX-1 is essential for understanding how it affects various cellular outcomes. Expression array analysis was used to identify glial cell-derived neurotropic factor receptor ${\alpha}1$ ($GFR{\alpha}1$), which is an encoding receptor for the glial cell-derived neurotropic factor (GDNF) family, the expression of which is induced by APEX-1. A target of GDNF/$GFR{\alpha}$ signaling, c-Src (Tyr418) was strongly phosphorylated by GNDF in the APEX-1 expressing cells. Moreover, GDNF initiated cell proliferation, measured by counting the number of cells, in the APEX-1 expressing cells. Importantly, the down-regulation of APEX-1 by siRNA caused a marked reduction in the $GFR{\alpha}1$ expression level, and it reduced the ability of GDNF to phosphorylate c-Src (Tyr418) and stimulate cell proliferation. These results demonstrate an association between APEX-1 and GDNF/$GFR{\alpha}$ signaling and suggest a potential molecular mechanism for the involvement of APEX-1 in cell survival and proliferation.

• Biomedical Science Letters
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• v.12 no.3
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• pp.275-279
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• 2006

It is demonstrated that cadmium has cytotoxic effect on glial cells, oxygen radicals are involved in cadmium-induced cytotoxicity. However, the toxic mechanism of cadmium is left unknown so far. The purpose of this study was to examine the cytotoxicity of $CdCl_2$ on $C_6$ glioma cells. The cytotoxicy was measured by cell viability via XTT assay in $C_6$ glioma cells. Colorimetric assay such as XTT assay is regarded as a very sensitive screening method for the determination of the cell viability on a lots of chemicals. In this study, $CdCl_2$ decreased cell viability according to the dose- and time dependent manners after $C_6$ glioma cells were treated with various concentrations of $CdCl_2$ for 48 hours. $IC_{90}\;and\;IC_{50}$ values for XTT assay was determined at $5{\mu}M\;and\;55{\mu}M$ of $CdCl_2$, respectively. These results suggest that $CdCl_2$ has highly cytotoxic effect on $C_6$glioma cells by the decrease of cell viability.

• Natural Product Sciences
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• v.24 no.3
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• pp.148-154
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• 2018

Chronic oxidative stress due to the accumulation of reactive oxygen species (ROS) in neuronal cells ultimately leads to neurodegenerative diseases. The use of natural therapies for the prevention of ROS-induced cell damage and for the treatment of neurodegenerative disorders has shown promising results. In this study, we evaluated the neuroprotective effects of the ethyl acetate (EtOAc) fraction of A. okamotoanum against the hydrogen peroxide ($H_2O_2$)-induced oxidative stress in C6 glial cells. Results show that cell viability was decreased in cells incubated with $H_2O_2$, whereas the addition of EtOAc fraction treatments in such cells significantly increased viability. The EtOAc fraction showed the highest inhibitory activity against ROS production and it also decreased the expressions of inflammatory proteins including cyclooxygenase-2, inducible nitric oxide synthase and interleukin-$1{\beta}$. Furthermore, the EtOAc fraction inhibited apoptosis by regulating the protein expressions cleaved caspase -9, -3, poly ADP ribose polymerase, Bax and Bcl-2. Therefore, these results show that the EtOAc fraction of A. Okamotoanum exhibits neuroprotective effects against $H_2O_2$ induced oxidative damage by regulating the inflammatory reaction and apoptotic pathway.

• Korean Journal of Veterinary Research
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• v.46 no.3
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• pp.177-184
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• 2006

Experimental autoimmune encephalomyelitis (EAE) is a disease model of multiple sclerosis (MS) that is characterized by remittance and relapse of the disease and autoimmune and demyelinating lesions in the central nervous system (CNS). Autoimmune inflammation is maintained by secretion of a large number of protein. Previous studies have suggested that transcripts encoding osteopontin (OPN) are frequently detected in the mRNA population of MS plaques. To elucidate the functional role of OPN in initiation and development of EAE, we examined the expression and localization of OPN in the spinal cord during acute EAE. We demonstrated that OPN significantly increased at the early stage of EAE and slightly declined thereafter by western blot analysis. An immunohistochemical study revealed that OPN was constitutively expressed in some glial cells (microglia, astrocytes) of white matter and neurons in the CNS of control rats. OPN expression was shown to be increased in the same cells at the early and peak stage of EAE. To identity cells expressing OPN by double-immunofluorescence labeling, we labeled rat spinal cord sections for OPN with a monoclonal OPN antibody and with mAbs for astrocyte (GFAP), microglia/macrophage (OX42)-specific markers. The major cell types of OPN-expressing cells were activated astrocytes and microglia in the adjacent inflammatory lesions. Interestingly, OPN was mainly expressed in the end feet of astrocytes around vascular cell adhesion molecule-1 (VCAM-1) expressing endothelial cells of CNS blood vessel. These findings suggest that increased levels of OPN in activated glial cell may play an important role in the recruitment of inflammatory cells into the CNS parenchyma during EAE.

• Korean Journal of Pharmacognosy
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• v.47 no.3
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• pp.251-257
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• 2016

In this study, the radical scavenging activity and protective effect of ethanol extract from leaf of Engelhardtia chrysolepis HANCE (ECE) against oxidative stress were investigated under in vitro and cellular system. ECE showed strong radical scavenging activities in 1,1-diphenyl-2-picrylhydrazyl, hydroxyl(${\cdot}OH$) and nitric oxide(NO) radical as a concentration-dependent manner. Particularly, strong scavenging activity against the ${\cdot}OH$ and NO radical were observed with the $IC_{50}$ value of $1.30{\mu}g/ml$ and $12.61{\mu}g/ml$, respectively. Furthermore, the cellular oxidative stress was induced by amyloid beta($A{\beta}_{25-35}$) in C6 glial cells. The treatment of $A{\beta}_{25-35}$ to C6 glial cells generated high levels of reactive oxygen species(ROS) and declined cell viability. However, production of ROS was decreased by the treatment of ECE. In addition, the cell viability was significantly increased at each concentration(10, 25, $50{\mu}g/ml$) as dose-dependent manner. The Alzheimer's disease-related protein expressions in $A{\beta}_{25-35}$-treated C6 glial cells were analyzed. The ECE treatment inhibited expression of amyloid precursor protein(APP), C-terminal fragment-${\beta}(CTF-{\beta})$, ${\beta}$-site APP cleaving enzyme(BACE), phosphorylated tau(p-tau) proteins in C6 glial cells induced by $A{\beta}_{25-35}$. The present study indicated that ECE has strong radical scavenging activity and neuroprotective effect through attenuating oxidative stress.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.782-791
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• 1997

Glial fibrillary acidic protein(GFAP) are a group of intermediate filaments that are distributed in the cytoplasm of many type of glial cells. The purpose of this study was to determine change of GFAP immunoreactivity(GFAP-IR) in rat trigeminal ganglion satellite cells in response to pulp exposure. The immunohistochemistry was carried out using the avidinbiotin-peroxidase complex(ABC) method and subsequently stained with AEC(3-aminoethyl-9-carbasol). 1. Contol group; Central root astrocytes had strong GFAP-IR, but ganglion satellite cells occasionlly had GFAP-IR. This reaction patterns of ganglion satellite cells was not concenturated in any specific region of trigeminal ganglion. 2. Three day pulp exposure group; There was a highly GFAP-IR in satellite cells of trigeminal ganglion in maxillary region. GFAP-IR in neighboring mandibular and ophthalmic regions was less intense compared to maxillary region. 3. Seven day pulp exposure group; In this group, GFAP-IR that was increased compared to control group was seen in the maxillary region. But GFAP-IR was less intense compared to three day pulp exposure group. These results suggest that GFAP in satellite cell increase in specific region of trigeminal ganglion after pulp exposure and offer useful tool in trigeminal pain research.

• Korean Journal of Veterinary Research
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• v.45 no.1
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• pp.7-15
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• 2005

To elucidate the roles of phospho-IkB expression in the development and progression of EAE, we investigated the expression of phospho-IkB in the central nervous system (CNS) of rats during experimental autoimmune encephalomyelitis (EAE) using immunohistochemistry and Western blot analysis. In Western blot analysis, the increased expression of phospho-IkB went parallel to severity of EAE. The expression of phospho-IkB increased significantly at the peak stage of EAE followed by gradual decrease. Immunohistochemical studies showed that the phospho-IkB immunoreactivity was mainly expressed in inflammatory cells (macrophages, T cells) and glial cells (astrocytes, microglial cells) at the peak stage of EAE and disappeared at the recovery stage. These findings suggest that the phosphorylation of IkB is closely associated with autoimmune inflammation in the CNS and plays an important role in the initiation and progression of EAE.

• Journal of Ginseng Research
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• v.28 no.2
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• pp.120-126
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• 2004

Glial cells such as astrocytes and microglial cells are the main source of proinflammatory cytokines and nitric oxide(NO) in the central nervous system, which exert neuroimmune and inflammatory functions and other various neurobiologic effects. Though Panax ginseng C.A. Meyer has been known to strengthen the body's defence mechanisms and also to maintain the homeostasis in the central nervous system, the effects of Panax ginseng on the production of immune and inflammatory mediators have not been studied well in the brain. Therefore, this study was designed to study the effects of ginseng saponins on the production of proinflammatory cytokines and NO in the primary cultures of mixed glial cells. White ginseng saponin, 200-500 $\mu$g/ml, showed significant cytotoxicity after 72 hrs and increased TNF-$\alpha$, IL-$\beta$, and NO production. Lower doses of 50-100 $\mu\textrm{g}$/ml showed little cytotoxicity until 72 hrs and also increased the production of TNF-$\alpha$, IL-1$\beta$, and NO. Triple immune staining showed that white ginseng saponin, 200$\mu\textrm{g}$/ml for 72 ks, induced stellation of astrocytes and iNOS expression exclusively in microglial cells. Taken together, the white ginseng saponin increased the production of proinflammatory cytokines such as TNF-$\alpha$ and IL-1$\beta$, and induced iNOS expression and NO production in mixed glial cell cultures, which may be ascribed to the enhancement of central immune responses and the regulation of inflammatory reactions by Panax ginseng.

• Molecules and Cells
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• v.26 no.2
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• pp.186-192
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• 2008

NELL2, a neural tissue-enriched protein, is produced in the embryo, and postembryonically in the mammalian brain, with a broad distribution. Although its synthesis is required for neuronal differentiation in chicks, not much is known about its function in the adult mammalian brain. We investigated the distribution of NELL2 in various regions of the adult rat brain to study its potential functions in brain physiology. Consistent with previous reports, NELL2-immunoreactivity (ir) was found in the cytoplasm of neurons, but not in glial fibrillary acidic protein (GFAP)-positive glial cells. The highest levels of NELL2 were detected in the hippocampus and the cerebellum. Interestingly, in the cerebellar cortex NELL2 was observed only in the GABAergic Purkinje cells not in the excitatory granular cells. In contrast, it was found mainly in the hippocampal dentate gyrus and pyramidal cell layer that contains mainly glutamatergic neurons. In the dentate gyrus, NELL2 was not detected in the GFAP-positive neural precursor cells, but was generally present in mature neurons of the subgranular zone, suggesting a role in this region restricted to mature neurons.