• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.1
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• pp.123-131
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• 2020

In this study, we investigated the protective effects of a Neutrase enzymatic hydrolysate derived from Korea pen shell Atrina pectinata (APN) against hydrogen peroxide (H₂O₂)-induced oxidative damage in hepatocytes. First, we confirmed that APN has antioxidant activities by scavenging 2,2-azino-bis (3-ethylbenzthiazoline)-6-sulfonic acid radical (ABTS⁺) and H₂O₂ and increasing oxygen radical absorbance capacity (ORAC) value. Also, the treatment of APN increased the cell viability by reducing the intracellular reactive oxygen species (ROS) production in H₂O₂-stimulated hepatocytes. In addition, APN decreased the sub-G₁ DNA contents and the apoptotic body formation increased by H₂O₂ stimulation. Moreover, APN modulated the protein expression of apoptosis related molecules (Bcl-2, Bax and p53) by suppressing the activation of nuclear factor NFkB and ERK/p38 signaling in H₂O₂-stimulated hepatocytes. Furthermore, APN led to the activation of Nrf2/HO-1signaling known as antioxidant systems. These results suggest APN protects hepatocytes against oxidative damages caused by H₂O₂ stimulation.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1355-1363
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• 2009

In the present study, the neuroprotective effects of astaxanthin on $H_2O_2$-mediated apoptotic cell death, using cultured mouse neural progenitor cells (mNPCs), were investigated. To cause apoptotic cell death, mNPCs were pretreated with astaxanthin for 8 h and followed by treatment of 0.3 mM $H_2O_2$. Pretreatment of mNPCs with astaxanthin significantly inhibited $H_2O_2$-mediated apoptosis and induced cell growth in a dose-dependent manner. In Western blot analysis, astaxanthin-pretreated cells showed the activation of p-Akt, p-MEK, p-ERK, and Bcl-2, and the reduction of p-P38, p-SAPK/JNK, Bax, p-GSK3b, cytochrome c, caspase-3, and PARP. Because $H_2O_2$ triggers caspases activation, this study examined whether astaxanthin can inhibit caspases activation in $H_2O_2$-treated mNPCs. After $H_2O_2$ treatment, caspases activities were prominently increased, but astaxanthin pretreatment significantly inhibited $H_2O_2$-mediated caspases activation. Astaxanthin pretreatment also significantly recovered the ATP production ability of $H_2O_2$-treated cells. These findings indicate that astaxanthin inhibits $H_2O_2$-mediated apoptotic features in mNPCs. Inhibition assays with SB203580 ($10\;{\mu}M$, a specific inhibitor of p38) and PD98059 ($10\;{\mu}M$, a specific inhibitor of MEK) clearly showed that astaxanthin can inhibit $H_2O_2$-mediated apoptotic death via modulation of p38 and MEK signaling pathways.

• Molecules and Cells
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• v.39 no.1
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• pp.46-52
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• 2016

It is increasingly apparent that nature evolved peroxiredoxins not only as $H_2O_2$ scavengers but also as highly sensitive $H_2O_2$ sensors and signal transducers. Here we ask whether the $H_2O_2$ sensing role of Prx can be exploited to develop probes that allow to monitor intracellular $H_2O_2$ levels with unprecedented sensitivity. Indeed, simple gel shift assays visualizing the oxidation of endogenous 2-Cys peroxiredoxins have already been used to detect subtle changes in intracellular $H_2O_2$ concentration. The challenge however is to create a genetically encoded probe that offers real-time measurements of $H_2O_2$ levels in intact cells via the Prx oxidation state. We discuss potential design strategies for Prx-based probes based on either the redoxsensitive fluorophore roGFP or the conformation-sensitive fluorophore cpYFP. Furthermore, we outline the structural and chemical complexities which need to be addressed when using Prx as a sensing moiety for $H_2O_2$ probes. We suggest experimental strategies to investigate the influence of these complexities on probe behavior. In doing so, we hope to stimulate the development of Prx-based probes which may spearhead the further study of cellular $H_2O_2$ homeostasis and Prx signaling.

• Journal of Physiology & Pathology in Korean Medicine
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• v.30 no.4
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• pp.242-249
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• 2016

This study was to investigate the anti-inflammatory effects of Prunellae Herba(PH). The generation of superoxide anion radical (․O₂-), nitric oxide (NO), peroxynitrite (ONOO-) and Prostaglandin E₂(PGE₂) were measured in the H₂O₂-Treated renal epithelial cells(LLC-PK1 cell) of mouse. And the effects of Prunellae Spica on the expression of NF-κB (p50, p65), IKK-α, phospho-IκB-α and inflammation-related proteins, COX-2, iNOS, IL-1β and VCAM-1, were examined by western blot. The fluorescent probes, 2',7'-dichlorodihydrofluorescein diacetate (DCFDA), 4,5-diaminofluorescein (DAF-2) and dihyldrorhodamine 123 (DHR 123) were used to estimate the scavenging effect of Prunellae Spica on ․O₂-, NO, ONOO-. Western blot was conducted to assess the protein expression levels of NF-κB (p50, p65), IKK-α, phospho-IκB-α, inflammation-related proteins, COX-2, iNOS, IL-1β, VCAM-1. PH inhibited H₂O₂-treated cell death dose-dependently. It reduced the generation of ·O₂-, NO, ONOO- and PGE₂ in the H₂O₂-treated renal epitheial cells(LLC-PK₁ cell) of mouse in vitro. PH reduced the expression of NF-κB, IKK-α, phospho-IκB-α, COX-2, iNOS, IL-1β and VCAM-1 genes through means of decreasing activation of NF-κB signaling as well. According to these results, PH has an antioxidative activity and anti-inflammatory effect by regulating the NF-κB pathway. This suggest that PH is expected to be used to regulating inflammatory process and treating inflammation-related disease.

• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.33-37
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• 2014

Objective: Low intensity pulsed ultrasound (LIPUS) has been shown to accelerate cell proliferation and tissue healing in both animal models and clinical trials. However, details of the clinical effects of LIPUS have not been well characterized. The aim of this study was to investigate the effect of LIPUS on mitogen-activated protein kinase (MAPK) activation in rat articular chondrocytes. Design: Cross-sectional study. Methods: Chondrocyte were cultured in six well cell culture plates for 72 hours at $37^{\circ}C$ with 5% $CO_2$, and then exposed to LIPUS at 1.5 MHz frequency and $30-mW/cm^2$ power. Changes in chondrocyte activities were evaluated in response to oxydative stress in dose-dependent (0 and 300 uM) and time-dependent (0-24 hr) manner. The cell viability were analyzed using MTT [3-(4.5-dimethylthiazol-2-yl)-2.5 diphenyltetrazolium bromide]. The expression of p38 MAPK was measured using western blotting. Results: Oxidative stress was induced in rat chondrocytes using hydrogen peroxide ($H_2O_2$). The cell viability was decreased in chondrocytes after the $H_2O_2$ dose and time-dependent treatment. The p38 MAPK phosphorylation occurred at a significantly increased rate after $H_2O_2$ treated (p<0.05). Expression of p38 MAPK was decreased in the p38 inhibitor groups compared with the oxidative stress-induced chondrocyte damage via the p38 MAPK signaling pathways (p<0.05). Conclusions: It could be concluded that LIPUS can inhibit oxidative stress-induced chondrocyte damage via the p38 MAPK signaling pathways.

• The Journal of Korean Medicine
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• v.22 no.4
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• pp.58-68
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• 2001

Objectives : This study was designed to investigate the protective mechanisms of Samul-tang (SMT) on $H_2O_2$-induced toxicity in H9c2 cardiomyoblast cells. Methods : The cultured cells were pretreated with SMT and exposed to $H_2O_2$. The cell damage was assessed by using MTT assay. Also, we used Hoechst staining, Western blotting analysis. Results : SMT significantly reduced both $H_2O_2$-induced cell death and chromatin fragmentation. The decrease of Bcl2 expression by $H_2O_2$ was inhibited by SMT. In addition, the increase of Bax expression was also inhibited by SMT. In particular, Fas expression, which is generally recognized as cell death inducing signal by Fas/FasL interaction, was markedly decreased by $H_2O_2$ in a time-dependent manner, whereas this decrease was completely prevented by SMT. The cotreatment of SMT and $H_2O_2$ in H9c2 cells also induced the phosphorylation of ERK in a time-dependent manner. Moreover, PD098059, a specific inhibitor of ERKl/2, attenuated the protective effect of SMT on $H_2O_2$-induced toxicity in H9c2 cardiomyoblast cells. Furthermore, the protective effect of SMT was significantly blocked by treatment of SB203580, a specific inhibitor of p38. Conclusions : Taken together, this study suggests that the protective effects of the water extract of SMT against oxidative damages may be mediated by the modulation of Bel2 and Bax expression via the regulation of ERK and p38 signaling pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.4
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• pp.1637-1642
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• 2015

Background: RhoGTPase-activating proteins (RhoGAPs) regulate RhoGTPases in cells, but whether individual reactive oxygen species (ROS) regulate RhoGAPs is unknown. Our previous published papers have shown that deleted in liver cancer 1 (DLC1) inhibits cancer cell migration by its RhoGAP activity. The present study was designed to explore the role of $H_2O_2$ in regulation of DLC1. Materials and Methods: We treated cells with $H_2O_2$ for 24h and phenotypic changes were analyzed by MTT, RT-PCR, Western blotting, immunofluorescence staining and wound healing assays. Results: $H_2O_2$ downregulated cyclin D1 and cyclin E to inhibit proliferation, and upregulated BAX to induce apoptosis in MCF-7 cells. Compared with non-tumorigenic cells, $H_2O_2$ increased expression of DLC1 and reduced activity of RhoA in cancer cells. Stress fiber production and migration were also suppressed by $H_2O_2$ in MDA-MB-231 cells. Conclusions: Our study suggests that $H_2O_2$ inhibits proliferation through modulation of cell cycle and apoptosis-related genes, and inhibits migration by decreasing stress fibers via DLC1/RhoA signaling.

• The Journal of Korean Medicine
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• v.21 no.4
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• pp.193-203
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• 2000

Objectives : Hindered barrier function of vascular endothelium has been implicated in the initiation and progression of degenerative vascular diseases such as atherosclerosis. In this study, the effect of Sunghyangchungisan(SHCS) as a protectant against oxidant-induced destruction of endothelial barrier function was assessed. Methods : Toward this end, endothelial cells derived from the human umbilical vein were cultured as monolayers on permeable membrane filters. Endothelial permeability was monitored by measuring transendothelial electrical resistance and movement of low density lipoprotein (LDL) across the endothelial monolayer. Results : Along with increased movement of LDL, $H_2O_2$-induced increase in endothelial permeability was paralleled by a decrease in transendotheliaI electrical resistance. The effect of $H_2O_2$ was mimicked by phorbol 12-myristate 13-acetate (PMA), a potent activator of proteinkinase C. Calphostin-C, a protein kinase C inhibitor, effectively blocked the increase in endothelial permeability induced by $H_2O_2$ or PMA, indicating that activation of protein kinase C is associated with the $H_2O_2-induced$ permeability change. SHCS effectively protected the endothelial monolayer against $H_2O_2-induced$ increase in permeability, whereas, it did not affect PMA-induced change. Forskolin, a potent activator of adenylyl cyclase, antagonized $H_2O_2$ to increase endothelial permeability. In addition, in ${H_2O_2}-treated$ cens, intracenular cAMP concentration was significantly decreased, indicating that impaired cAMP production as well as activation of proteinkinase C is a mechanism underlying ${H_2O_2}>-induced$$H_2O_2$ with regard to its effect on intracellular cAMP content. However, SHCS itself did not affect resting cAMP concentration in endothelial cells. Conclusions : These results suggest that SHCS might operate as an effective protectant against oxidant-induced destruction of endothelial barrier function. The mechanism does not appear to involve direct interaction with protein kinase C- or cAMP-associated signaling mechanism.

• The Journal of Korean Medicine
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• v.26 no.1 s.61
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• pp.174-186
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• 2005

Objectives : The water extract of Samul-tang (SMT) has traditionally been used for treatment of ischemic heart and brain damage in oriental medicine. However, little is known about the mechanism by which the water extract of SMT rescues cells from these damages. Methods: This study was designed to investigate the protective mechanisms of SMT on oxidative stress-induced toxicity in H9c2 cardiomyoblast cells. Treatment with $H_2O_2$ markedly induced death of H9c2 cardiomyoblast cells in a dose-dependent manner. Results: The characteristics of H20z-induced death of H9c2 showed apparent apoptotic features such as DNA fragmentation and morphological change. However, SMT significantly reduced both H202-induced cell death and morphological change. The decrease of Bc-2 expression by High were inhibited by SMT. In addition, the increase of Bax expression was also inhibited by SMT. The cotreatment of SMT and $H_2O_2$ in H9c2 cells also induced the phosphorylation of ERK in a time-dependent manner. Moreover, PD98059, a specific inhibitor of ERK1/2 attenuated the protective effects of SMT on $H_2O_2-induced$ toxicity in H9c2 cardiomyoblast cells. These results suggest that both ERK1/2 signaling pathways play important roles in the protective effects of SMT on $H_2O_2-induced$ apoptotic death of H9c2 cells. Also, the expression profile of proteins in $H_2O_2$ cardiomyoblast cells were screened by using two-dimensional (2-D) gel electrophoresis. Among 300 spots resolved in 2-D gels, the comparison of control versus apoptosis cells revealed that signal intensity of 17 spots increased and 11 spots decreased. Conclusions: Taken together, this study suggests that the protectiw effects of the water extract of SMT against oxidative damages may be mediated by the modulation of Bc1-2 and Bax expression via the regulation of the ERK signaling pathway.

• KSBB Journal
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• v.21 no.1 s.96
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• pp.16-19
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• 2006

Oxidative modification of nucleoside diphosphate kinase (NDPK) is identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometer. The quaternary structure of NDPK appears to be regulated by cross-linking with an oxidant, $H_2O_2$. We compared roles of NDPK in each of wild type and ynk mutant against oxidative stress. Six specific proteins changed by $H_2O_2$ were identified using two-dimensional electrophoretic analysis. YNK regulated several proteins, related to $H_2O_2$ signaling functions. These results suggest that one of the important functions of NDPK is the regulation of cellular redox state.