• Title, Summary, Keyword: ROS

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Rhamnazin inhibits LPS-induced inflammation and ROS/RNS in raw macrophages

  • Kim, You Jung
    • Journal of Nutrition and Health
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    • v.49 no.5
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    • pp.288-294
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    • 2016
  • Purpose: The aim of this work was to investigate the beneficial effects of rhamnazin against inflammation, reactive oxygen species (ROS)/reactive nitrogen species (RNS), and anti-oxidative activity in murine macrophage RAW264.7 cells. Methods: To examine the beneficial properties of rhamnazin on inflammation, ROS/ RNS, and anti-oxidative activity in the murine macrophage RAW264.7 cell model, several key markers, including COX and 5-LO activities, $NO^{\cdot}$, $ONOO^-$, total reactive species formation, lipid peroxidation, $^{\cdot}O_2$ levels, and catalase activity were estimated. Results: Results show that rhamnazin was protective against LPS-induced cytotoxicity in macrophage cells. The underlying action of rhamnazin might be through modulation of ROS/RNS and anti-oxidative activity through regulation of total reactive species production, lipid peroxidation, catalase activity, and $^{\cdot}O_2$, $NO^{\cdot}$, and $ONOO^{\cdot}$ levels. In addition, rhamnazin down-regulated the activities of pro-inflammatory COX and 5-LO. Conclusion: The plausible action by which rhamnazin renders its protective effects in macrophage cells is likely due to its capability to regulate LPS-induced inflammation, ROS/ RNS, and anti-oxidative activity.

Function of NADPH Oxidases in Diabetic Nephropathy and Development of Nox Inhibitors

  • Lee, Sae Rom;An, Eun Jung;Kim, Jaesang;Bae, Yun Soo
    • Biomolecules & Therapeutics
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    • v.28 no.1
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    • pp.25-33
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    • 2020
  • Several recent studies have reported that reactive oxygen species (ROS), superoxide anion and hydrogen peroxide (H2O2), play important roles in various cellular signaling networks. NADPH oxidase (Nox) isozymes have been shown to mediate receptor-mediated ROS generation for physiological signaling processes involved in cell growth, differentiation, apoptosis, and fibrosis. Detectable intracellular levels of ROS can be induced by the electron leakage from mitochondrial respiratory chain as well as by activation of cytochrome p450, glucose oxidase and xanthine oxidase, leading to oxidative stress. The up-regulation and the hyper-activation of NADPH oxidases (Nox) also likely contribute to oxidative stress in pathophysiologic stages. Elevation of the renal ROS level through hyperglycemia-mediated Nox activation results in the oxidative stress which induces a damage to kidney tissues, causing to diabetic nephropathy (DN). Nox inhibitors are currently being developed as the therapeutics of DN. In this review, we summarize Nox-mediated ROS generation and development of Nox inhibitors for therapeutics of DN treatment.

Free Radical Toxicology and Cancer Chemoprevention

  • Lin, Jen-Kun
    • Toxicological Research
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    • v.17
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    • pp.83-88
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    • 2001
  • Most reactive oxygen species (ROS) are free radicals and implicated in the development of a number of disease processes including artherosclerosis, neurodegenerative disorders, aging and cancer. ROS are byproducts of a number of in vivo metabolic processes and are formed deliberately as part of nor-mal inflammatory response. On the other hand, ROS are generated either as by products of oxygen reduction during xenobiotic metabolism or are liberated as the result of the futile redox cycling of the chemical agents including several chemical carcinogens. A better understanding of the mechanisms of free radical toxicity may yield valuable clue to risks associated with chemical exposures that leading to the development of chronic diseases including cancer. The molecular biology of ROS-mediated alterations in gene expression, signal transduction and carcinognesis is one of the important subjects in free radical toxicology. Epidemiological studies suggest that high intake of vegetables and fruits are associated with the low incidence of human cancer. Many phytopolyphenols such as tea polyphenols, curcumin, resveratrol, apigenin, genistein and other flavonoids have been shown to be cancer chemopreventive agents. Most of these compounds are strong antioxidant and ROS scavengers in vitro and effective inducers of antioxidant enzymes such as superoxide dismutatse, catalase and glutathione peroxidase in vivo. Several cellular transducers namely receptor tyrosine kinase, protein kinase C, MAPK, PI3K, c-jun, c-fos, c-myc, NFkB, IkB kinase, iNOS, COX-2, Bcl-2, Bax, etc have been shown to be actively modulated by phyto-polyphenols. Recent development in free radical toxicology have provided strong basis for understanding the action mechanisms of cancer chemoprevention.

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Toxic Activities of the Oxidant Chromate in Culture Cells (산화성 크롬의 배양세포에서의 독성작용)

  • 박형숙
    • Environmental health and toxicology
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    • v.13 no.1_2
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    • pp.1-9
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    • 1998
  • The ROS-producing potency of chromium compounds of several oxidation states were determined in the H4 cells. $K_2Cr_2O_7$ as Cr (VI), synthetic Cr (V) compounds and Cr (III) as TPP produced high level of ROS. However, ROS values of Cr-picolinate as Cr (III), CrCl$_2$, CrCI$_2$, were almost equal to the control. The effects of physiological antioxidants compounds which react with free radicals were examined for their effects on chromate-induced production of reactive oxygen species (ROS) in A549 cells after the addition of $K_2Cr_2O_7$. The compounds used were vitamin C (ascorbate), vitamin E ($\alpha$-tocopherol), superoxide dismutase (SOD) and catalase. The preincubation of ascorbate (200uM) with A549 cells for 20hr resulted in a significant reduction of hexavalent chromate(100uM) induced ROS. However, there is no effects of preincubation of the cells with vitamin E succinate (10 and 20uM, 20hr) on the ROS production. Also, the effects of Cr (VI) on the cell cycle of A549 cells was measured by adding the DNA intercalating agent, propidium iodide. S phase of the cell cycle was increased by the chromium (VI) compounds up to 20uM indicating toxicity or possible mitogenic action of the cell. The shoulder in Go/G1 phase at 20uM Cr (VI) with 24 hr treatment indicates apoptosis.

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Induction of Oxidative Stress by Hexavalent Chromium in Human Bronchial Epithelial Cells (BEAS-2B) (배양 기관지 상피세포(BEAS-2B cells)에서 6가 크롬에 의한 산화적 스트레스)

  • Park, Eun-Jung;Kang, Mi-Sun;Kim, Dae-Seon;Park, Kwang-Sik
    • Environmental health and toxicology
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    • v.21 no.4
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    • pp.357-363
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    • 2006
  • Chromium compounds are widely used in diverse industries including pigment manufacturing, painting, metal plating and leather tanning. With the wide uses of chromium, various adverse effects of the compounds on the environment and human health have been reported. Among them, hexavalent chromium [Cr (VI)], which is a carcinogenic heavy metal, has been widely studies. Epidemiological investigations have shown that respiratory cancers had been found in workers who had been occupationally exposed to Cr (VI). In this study, cell toxicity and induction of reactive oxygen species (ROS) by Cr (VI) (1, 2, 4, $8{\mu}M$) in cultured human bronchial epithelial cells were investigated. Exposure of the cells to Cr (VI) led to cell death, ROS increase, and cytosolic caspase-3 activation. The ROS increase was related with the decreased level of GSH. Chromatin condensation and fragmentation were occurred by Cr (VI) when evaluated by DAPI staining or agarose gel electrophoresis of the extracted DNA. Expression of ROS related genes including glutathione S-transferase, heme oxygenase-1, metallothionein were significantly induced in Cr (VI) treated cells. This result suggests the toxicity in cultured cells by Cr (VI) was expressed through the apoptotic process with ROS induction.

Implementation of a Refusable Human-Robot Interaction Task with Humanoid Robot by Connecting Soar and ROS (Soar (State Operator and Result)와 ROS 연계를 통해 거절가능 HRI 태스크의 휴머노이드로봇 구현)

  • Dang, Chien Van;Tran, Tin Trung;Pham, Trung Xuan;Gil, Ki-Jong;Shin, Yong-Bin;Kim, Jong-Wook
    • The Journal of Korea Robotics Society
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    • v.12 no.1
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    • pp.55-64
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    • 2017
  • This paper proposes combination of a cognitive agent architecture named Soar (State, operator, and result) and ROS (Robot Operating System), which can be a basic framework for a robot agent to interact and cope with its environment more intelligently and appropriately. The proposed Soar-ROS human-robot interaction (HRI) agent understands a set of human's commands by voice recognition and chooses to properly react to the command according to the symbol detected by image recognition, implemented on a humanoid robot. The robotic agent is allowed to refuse to follow an inappropriate command like "go" after it has seen the symbol 'X' which represents that an abnormal or immoral situation has occurred. This simple but meaningful HRI task is successfully experimented on the proposed Soar-ROS platform with a small humanoid robot, which implies that extending the present hybrid platform to artificial moral agent is possible.

Role of NADPH Oxidase-mediated Generation of Reactive Oxygen Species in the Apigenin-induced Melanogenesis in B16 Melanoma Cells (B16 흑색종세포에서 아피제닌에 의한 멜라닌 합성에 미치는 NADPH 산화효소-유래 활성산소종의 역할)

  • Lee, Yong-Soo
    • YAKHAK HOEJI
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    • v.55 no.6
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    • pp.485-491
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    • 2011
  • Previously, we have reported that apigenin, a natural flavonoid found in a variety of vegetables and fruits, stimulated melanogenesis through the activation of $K^+-Cl^-$-cotransport (KCC) in B16 melanoma cells. In this study we investigated the possible involvement of reactive oxygen species (ROS) in the mechanism of apigenin-induced melanogenesis in B16 cells. Apigenin elevated intracellular ROS level in a dose-dependent manner. Treatment with various inhibitors of NADPH oxidase, diphenylene iodonium (DPI), apocynin (Apo) and neopterine (NP) significantly inhibited both the generation of ROS and melanogenesis induced by apigenin. In addition these inhibitors profoundly inhibited apigenin-induced $Cl^-$-dependent $K^+$ efflux, a hallmark of KCC activity. However, the apigenin-induced ROS generation was not significantly affected by treatment with a specific KCC inhibitor R-(+)-[(2-n-butyl-6,7-dichloro-2-cyclopentyl-2,3-dihydro-1-oxo-1H-inden-5-yl)oxy]acetic acid (DIOA). These results indicate that the ROS production may be a upstream regulator of the apigenin-induced KCC stimulation, and in turn, melanogenesis in the B16 cells. Taken together, these results suggest that the NADPH oxidase-mediated ROS production may play an important role in the apigenin-induced melanogenesis in B16 cells. These results further suggest that NADPH oxidase may be a good target for the management of hyperpigmentation disorders.

Hypoxia Induces Paclitaxel-Resistance through ROS Production

  • Oh, Jin-Mi;Ryu, Yun-Kyoung;Lim, Jong-Seok;Moon, Eun-Yi
    • Biomolecules & Therapeutics
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    • v.18 no.2
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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.

Reactive Oxygen Species-Induced Expression of B cell Activating Factor (BAFF) Is Independent of Toll-like Receptor 4 and Myeloid Differentiation Primary Response Gene 88

  • Kim, Hyun-Sun;Moon, Eun-Yi
    • Biomolecules & Therapeutics
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    • v.17 no.2
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    • pp.144-150
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    • 2009
  • Reactive oxygen species play a role in signal transduction and in many human diseases. B-cell activating factor (BAFF) plays a role for mature B cell generation and maintenance and for the incidence of autoimmune diseases. We previously reported that BAFF expression was induced by ROS. In this study, we investigated whether ROS-induced BAFF expression was affected by toll-like receptor (TLR) 4 or myeloid differentiation primary response gene (MyD) 88. BAFF expression was increased by serum deprivation that is an experimental modification to produce ROS. In contrast, TLR4 and MyD88 were decreased by serum deprivation. Although ROS production was decreased in TLR4-nonfunctional or MyD88-deficient splenocytes as compared to that in control mice, serum deprivation increased ROS production and augmented BAFF expression in both cells. $50{\mu}M\;H_2O_2$ also increased BAFF expression in TLR4-deficient or MyD88-deficient splenocytes. Collectively, results show that BAFF expression may be mediated by TLR4 or MyD88-independent manner and TLR4 or MyD88 may not be required in BAFF expression.

Effect of Dioxin on the Change of Mitochondrial Inner Membrane Potential and the Induction of ROS (다이옥신이 미토콘드리아 내막의 전위차 변화 및 ROS 생성에 미치는 영향)

  • Cho, Il-Young;Sheen, Yhun-Yhong
    • Environmental health and toxicology
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    • v.24 no.1
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    • pp.33-41
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    • 2009
  • Among the toxicants in the environment dioxin-like compounds, including TCDD(2,3,7,8-Tetrachlorodibenzo-p-Dioxin), are well known as carcinogen and teratogen. TCDD the most toxic of these compounds, may result in a wide variety of adverse health effects in humans and environment, including carconogenesis, hepatotoxicity, teratogenesis, and immunotoxicity. Also TCDD increases superoxide, peroxide radicals and induces oxidative stress that leads to breakage of DNA single-strand and mitochondrial dysfunction. Recently, there have been reports that persistent organic pollutants(POPs) may be causing metabolic disease through mitochondrial toxicity. In order to examine if dioxin brings about toxicity on mitochondria directly, we measured the change of the mitochondrial membrane potential after exposure to TCDD using JC-1 dye. After short time exposure of dioxin, mitochondrial depolarization was observed but it recovered to the control level immediately. This TCDD effect on mitochondrial membrane potential was not correlated either to the production of reactive oxygen species(ROS) or extracellular $Ca^{2+}$ by TCDD. Less than 2 hours exposure of TCDD did not show any change in ROS production but 0.25 nM TCDD for 48 hours or 0.5 nM TCDD for 12 hours exposure did increase in ROS production. Under these conditions of ROS production by TCDD, no changes in the mitochondrial membrane potential by TCDD was observed.