• The Korean Journal of Physiology and Pharmacology
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• 제14권6호
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• pp.391-397
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• 2010

E2F transcription factors and their target genes have been known to play an important role in cell growth control. We found that curcumin, a polyphenolic phytochemical isolated from the plant Curcuma longa, markedly suppressed E2F4 expression in HCT116 colon cancer cells. Hydrogen peroxide was also found to decrease E2F4 protein level, indicating the involvement of reactive oxygen species (ROS) in curucmin-induced downregulation of E2F4 expression. Involvement of ROS in E2F4 downregulation in response to curcumin was confirmed by the result that pretreatment of cells with N-acetylcystein (NAC) before exposure of curcumin almost completely blocked the reduction of E2F4 expression at the protein as well as mRNA level. Anti-proliferative effect of curcumin was also suppressed by NAC which is consistent to previous reports showing curcumin-superoxide production and induction of poly (ADP-ribose) polymerase (PARP) cleavage as well as apoptosis. Expression of several genes, cyclin A, p21, and p27, which has been shown to be regulated in E2F4-dependent manner and involved in the cell cycle progression was also affected by curcumin. Moreover, decreased (cyclin A) and increased (p21 and p27) expression of these E2F4 downstream genes by curcumin was restored by pretreatment of cells with NAC and E2F4 overexpression which is induced by doxycycline. In addition, E2F4 overexpression was observed to partially ameliorate curcumin-induced growth inhibition by cell viability assay. Taken together, we found curcumin-induced ROS down-regulation of E2F4 expression and modulation of E2F4 target genes which finally lead to the apoptotic cell death in HCT116 colon cancer cells, suggesting that E2F4 appears to be a novel determinant of curcumin-induced cytotoxicity.

• Journal of Microbiology and Biotechnology
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• 제27권6호
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• pp.1163-1170
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• 2017

Clostridium difficile releases two exotoxins, toxin A and toxin B, which disrupt the epithelial cell barrier in the gut to increase mucosal permeability and trigger inflammation with severe diarrhea. Many studies have suggested that enteric nerves are also directly involved in the progression of this toxin-mediated inflammation and diarrhea. C. difficile toxin A is known to enhance neurotransmitter secretion, increase gut motility, and suppress sympathetic neurotransmission in the guinea pig colitis model. Although previous studies have examined the pathophysiological role of enteric nerves in gut inflammation, the direct effect of toxins on neuronal cells and the molecular mechanisms underlying toxin-induced neuronal stress remained to be unveiled. Here, we examined the toxicity of C. difficile toxin A against neuronal cells (SH-SY5Y). We found that toxin A treatment time- and dose-dependently decreased cell viability and triggered apoptosis accompanied by caspase-3 activation in this cell line. These effects were found to depend on the up-regulation of reactive oxygen species (ROS) and the subsequent activation of p38 MAPK and induction of $p21^{Cip1/Waf1}$. Moreover, the N-acetyl-$\text\tiny L$-cysteine (NAC)-induced down-regulation of ROS could recover the viability loss and apoptosis of toxin A-treated neuronal cells. These results collectively suggest that C. difficile toxin A is toxic for neuronal cells, and that this is associated with rapid ROS generation and subsequent p38 MAPK activation and $p21^{Cip1/Waf1}$ up-regulation. Moreover, our data suggest that NAC could inhibit the toxicity of C. difficile toxin A toward enteric neurons.

• Nutrition Research and Practice
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• 제11권5호
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• pp.357-364
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• 2017

BACKGROUND/OBJECTIVES: Oxidative stress is closely related with inflammation and development of many diseases. Black soybean seed coat contains high amount of anthocyanins, which are well-known for free radical scavenging activities. This study investigated inflammatory response and action mechanism of black soybean anthocyanins with regard to antioxidant activity in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells. MATERIALS/METHODS: RAW 264.7 cells were treated with anthocyanins extracted from black soybean seed coats in a concentration range of 12.5 to $100{\mu}g/mL$. The production of reactive oxygen species (ROS), secretion of pro-inflammatory mediators and cytokines, and the signaling in the mitogen activated protein kinases (MAPKs) pathway were examined. RESULTS: Black soybean anthocyanins significantly decreased LPS-stimulated production of ROS, inflammatory mediators such as nitric oxide (NO) and prostaglandin $E_2$, and pro-inflammatory cytokines, including tumor necrosis factor ${\alpha}$ and interleukin-6, in a dose-dependent manner without cytotoxicity (P < 0.001). Black soybean anthocyanins downregulated the expression of inducible NO synthase and cyclooxygenase-2 in LPS-stimulated RAW 264.7 cells (P < 0.001). Moreover, black soybean anthocyanins inhibited LPS-induced phosphorylation of MAPKs, including extracellular signal-regulated kinase, c-Jun N-terminal kinase, and p38 (P < 0.001). CONCLUSION: These results suggest that black soybean anthocyanins exert anti-inflammatory activity by inhibiting ROS generation and subsequent MAPKs signaling, thereby inhibiting inflammatory responses.

• BMB Reports
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• 제46권9호
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• pp.460-464
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• 2013

The progression of androgenetic alopecia is closely related to androgen-inducible transforming growth factor (TGF)-${\beta}1$ secretion by hair follicle dermal papilla cells (DPCs) in bald scalp. Physiological levels of androgen exposure were reported to increase reactive oxygen species (ROS) generation. In this study, rat vibrissae dermal papilla cells (DP-6) transfected with androgen receptor showed increased ROS production following androgen treatment. We confirmed that TGF-${\beta}1$ secretion is increased by androgen treatment in DP-6, whereas androgen-inducible TGF-${\beta}1$ was significantly suppressed by the ROSscavenger, N-acetyl cysteine. Therefore, we suggest that induction of TGF-${\beta}1$ by androgen is mediated by ROS in hair follicle DPCs.

• 한방안이비인후피부과학회지
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• 제17권1호
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• pp.16-33
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• 2004

In Oriental medicine, aging is just a natural process like change of seasons. Ancient Oriental people accepted it as a natural thing to be growing older and to die at last. The science of aging has advanced dramatically. In the last 2 decades, advances in genetics and molecular biology have led to extraordinary new understandings in how cells age, how apoptosis programs cells to die, and how neuroendocrinology plays a role in the lifespan of organisms. Today, the matter of primary concern about aging is a cellular and mitochondrial damage of human body induced by reactive oxygen species(ROS). The skin aging can be divided into two areas, intrinsic(chronologic)-aging and photo-aging. There are lots of photo damage about skin aging. The skin is increasingly exposed to ultraviolet(UV) irradiation in life. Therefore, the risk of photo-oxidative damage of the skin induced by reactive oxygen species(ROS) has increased substantially. Nowadays, many people believe that they can stop or at least delay the process of aging. There are lots of treatments that promise to slow the process of aging and the associated ailments. Many of these treatments, for example, exercise, Vit E, Vit C therapy, hormone therapy, restrict diet, are gradually being subjected to clinical trials. But in spite of all efforts, researches and investigations, there is no single method or treatment which is revealed to be truly effective for delaying progress of aging. Every methods insisted on effect for delaying aging process, has its dark side. All we can do is just keeping ourself healthy until the time of death.

• Molecules and Cells
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• 제28권4호
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• pp.321-329
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• 2009

Rapid production of nitric oxide (NO) and reactive oxygen species (ROS) has been implicated in the regulation of innate immunity in plants. A potato calcium-dependent protein kinase (StCDPK5) activates an NADPH oxidase StRBOHA to D by direct phosphorylation of N-terminal regions, and heterologous expression of StCDPK5 and StRBOHs in Nicotiana benthamiana results in oxidative burst. The transgenic potato plants that carry a constitutively active StCDPK5 driven by a pathogen-inducible promoter of the potato showed high resistance to late blight pathogen Phytophthora infestans accompanied by HR-like cell death and $H_2O_2$ accumulation in the attacked cells. In contrast, these plants showed high susceptibility to early blight necrotrophic pathogen Alternaria solani, suggesting that oxidative burst confers high resistance to biotrophic pathogen, but high susceptibility to necrotrophic pathogen. NO and ROS synergistically function in defense responses. Two MAPK cascades, MEK2-SIPK and cytokinesis-related MEK1-NTF6, are involved in the induction of NbRBOHB gene in N. benthamiana. On the other hand, NO burst is regulated by the MEK2-SIPK cascade. Conditional activation of SIPK in potato plants induces oxidative and NO bursts, and confers resistance to both biotrophic and necrotrophic pathogens, indicating the plants may have obtained during evolution the signaling pathway which regulates both NO and ROS production to adapt to wide-spectrum pathogens.

• Molecules and Cells
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• 제42권12호
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• pp.884-892
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• 2019

Piperlongumine (PL), a natural alkaloid compound isolated from long pepper (Piper longum), can selectively kill cancer cells, but not normal cells, by accumulation of reactive oxygen species (ROS). The objective of this study was to investigate functional roles of expression of SETDB1 and FosB during PL treatment in MCF7 breast cancer cells. PL downregulates SETDB1 expression, and decreased SETDB1 expression enhanced caspase 9 dependent-PARP cleavage during PL-induced cell death. PL treatment generated ROS. ROS inhibitor NAC (N-acetyl cysteine) recovered SETDB1 expression decreased by PL. Decreased SETDB1 expression induced transcriptional activity of FosB during PL treatment. PARP cleavage and positive annexin V level were increased during PL treatment with FosB overexpression whereas PARP cleavage and positive annexin V level were decreased during PL treatment with siFosB transfection, implying that FosB might be a pro-apoptotic protein for induction of cell death in PL-treated MCF7 breast cancer cells. PL induced cell death in A549 lung cancer cells, but molecular changes involved in the induction of these cell deaths might be different. These results suggest that SETDB1 mediated FosB expression may induce cell death in PL-treated MCF7 breast cancer cells.

• Tuberculosis and Respiratory Diseases
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• 제73권2호
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• pp.84-92
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• 2012

Background: Asian dust storms can be transported across eastern Asia. In vitro, Asian dust particle-induced inflammation and enhancement of the allergic reaction have been observed. However, the fibrotic effects of Asian dust particles are not clear. Production of transforming growth factor ${\beta}_1$ (TGF-${\beta}_1$) and fibronectin were investigated in the bronchial epithelial cells after exposure to Asian dust particulate matter (AD-PM10). Methods: During Asian dust storm periods, air samples were collected. The bronchial epithelial cells were exposed to AD-PM10 with and without the antioxidant, N-acetyl-L-cysteine (NAC). Then TGF-${\beta}_1$ and fibronectin were detected by Western blotting. The reactive oxygen species (ROS) was detected by the measurement of dicholorodihydrofluorescin (DCF), using a FACScan, and visualized by a confocal microscopy. Results: The expression of TGF-${\beta}_1$, fibronectin and ROS was high after being exposed to AD-PM10, compared to the control. NAC attenuated both TGF-${\beta}_1$ and fibronectin expression in the AD-PM10-exposed the bronchial epithelial cells. Conclusion: AD-PM10 may have fibrotic potential in the bronchial epithelial cells and the possible mechanism is AD-PM10-induced intracellular ROS.

• BMB Reports
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• 제56권3호
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• pp.202-207
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• 2023

We investigated the neuroprotective effects of deca nano-graphene oxide (daNGO) against reactive oxygen species (ROS) and inflammation in the human neuroblastoma cell line SH-SY5Y and in the 6-hydroxydopamine (6-OHDA) induced Parkinsonian rat model. An MTT assay was performed to measure cell viability in vitro in the presence of 6-OHDA and/or daNGO. The intracellular ROS level was quantified using 2',7'-dichlorofluorescein diacetate. daNGO showed neuroprotective effects against 6-OHDA-induced toxicity and also displayed ROS scavenging properties. We then tested the protective effects of daNGO against 6-OHDA induced toxicity in a rat model. Stepping tests showed that the akinesia symptoms were improved in the daNGO group compared to the control group. Moreover, in an apomorphine-induced rotation test, the number of net contralateral rotations was decreased in the daNGO group compared to the control group. By immunofluorescent staining, the animals in the daNGO group had more tyrosine hydroxylase-positive cells than the controls. By anti-Iba1 staining, 6-OHDA induced microglial activation showed a significantly decrease in the daNGO group, indicating that the neuroprotective effects of graphene resulted from anti-inflammation. In conclusion, nano-graphene oxide has neuroprotective effects against the neurotoxin induced by 6-OHDA on dopaminergic neurons.

• 한국임상수의학회지
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• 제32권2호
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• pp.135-140
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• 2015

염증상태에서의 CLA의 효과와 작용기전을 알아보기 위해 LPS로 자극한 RAW 264.7 세포에 있어서 ROS와 NO생산 및 NF-${\kappa}B$ 활성에 대한 t10c12-CLA의 효과를 검토하였다. 또한 이러한 효과가 세포질 내 칼슘이온의 변화와 관련이 있는지도 알아보았다. LPS 자극으로 ROS 생산은 증가하였고 이러한 증가는 칼슘결합제인 BAPTA/AM에 의해 감소하였다. t10c12-CLA 또한 LPS 자극 RAW 264.7 세포의 ROS 생산 증가를 억제시켰으며 BAPTA/AM과 함께 처리시 더욱 억제되었다. NO의 생산과 NF-${\kappa}B$ p65 활성도 t10c12-CLA, BAPTA/AM, t10c12-CLA와 BAPTA/AM의 동시처리 모두에서 현저하게 억제되었다. 이상의 결과로부터 염증 조건에서 CLA는 과도한 ROS와 NO의 생산 및 NF-${\kappa}B$의 활성을 칼슘 의존적으로 억제하여 항염증 효과를 발휘하는 것으로 생각되었다.