• Journal of Life Science
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• v.24 no.7
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• pp.777-783
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• 2014

Cathepsin D (CtsD), an aspartyl peptidase, is involved in apoptosis, resulting in the release of cytochrome C from mitochondria in cells. Here, we investigated microRNA regulation of CtsD expression in 3T3-L1 cells. First, we observed the expression of CtsD in cells in response to doxorubicin (Dox). As expected, the level of CtsD mRNA increased in 3T3-L1 cells exposed to Dox in a dose-dependent manner. The cellular viability of ectopically expressed CtsD cells was decreased. Next, we used the miRanda program to search for particular microRNA targeting CtsD. MiR-145 was selected as a putative controller of CtsD because it had a high mirSVR score. In a reporter assay, the luciferase activity of cells containing the CtsD 3'-UTR region decreased in cells transfected with a miR-145 mimic compared to that of a control. The level of CtsD expression was down-regulated in preadipocytes ectopically expressing miR-145 and up-regulated by an miR-145 inhibitor. Cells also suppressed miR-145 expression when exposed to Dox. The miR-145 inhibitor reduced the cellular viability of 3T3-L1 cells. Taken together, these data suggest that miR-145 regulates CtsD-mediated cell death in adipocytes. These findings may have valuable implications concerning the molecular mechanism of CtsD-mediated cell death in obesity, suggesting that CtsD could be a useful therapeutic tool for the prevention and treatment of obesity by regulating fat cell numbers.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.1
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• pp.34-46
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• 2019

This paper provides the numerical results for the self-propulsion performance in waves of a car ferry vessel with damage in one of its twin-screw propulsion systems without flooding the engine room. The numerical simulations were carried out according to the Safe Return to Port (SRtP) regulation made by the Lloyd's register, where the regulation requires that damaged passenger ships should have an ability to return to port with a speed of 6 knots in a Beaufort 8 sea condition. For the validation of the present numerical analysis study, the resistance performance and the self-propulsion performance of the car ferry in intact and damaged conditions in calm water were calculated, which showed a satisfactory agreement with the model test results of Korea Research Institute of Ship and Ocean engineering (KRISO). Finally, the numerical simulation of self-propulsion performance in waves of the damaged car ferry ship was carried out for a normal sea state and for a Beaufort 8 sea state, respectively. The estimated average Brake Horse Power (BHP) for keeping the damaged car ferry ship advancing at a speed of 6 knots in a Beaufort 8 sea state reached about 47% of BHP at MCR condition or about 56% of BHP at NCR condition of the engine determined at the design state. In conclusion, it can be noted that the engine power of the damaged car ferry ship in single propulsion condition is sufficient to satisfy the SRtP requirement.

• Herbal Formula Science
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• v.29 no.2
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• pp.71-80
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• 2021

Objectives : This study investigated cellular-protective effects of Nardotidis seu Sulculii Concha water extract (NSCE) against oxidative stress induced by arachidonic acid (AA)+iron or tert-butylhydroperoxide (tBHP). Methods : In vitro, MTT assay was assessed for cell viability, and immunoblotting analysis was performed to detect expression of AMP-activated kinase (AMPK) signaling pathway and autophagy related proteins. In vivo, mice were orally administrated with the aqueous extract of NSCE of 500 mg/kg for 3 days, and then injected with CCl₄ 0.5 mg/kg body weight to induce acute damage. The level of liver damage was measured by serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) analysis. Results : Treatment with NSCE inhibited cell death induced by AA+iron and tBHP. NSCE induced the phosphorylation of AMPK, and this compound also induced the phosphorylation of LKB1, an upstream kinase of AMPK, and Acetyl-CoA carboxylase (ACC), a primary downstream target of AMPK. NSCE increased the protein levels of autophagic markers (LC3II and beclin-1) and decreased the phosphorylation of mammalian target of rapamycin (mTOR) and simultaneously increased the phosphorylation of unc-51-like kinase-1 (ULK-1) in time-dependent manner. Conclusions : NSCE has the ability 1) to protect cells against oxidative stress induced by AA+iron or tBHP. NSCE 2) to activate AMP-activated protein kinase (AMPK), and 3) to regulate autophagy, an important regulator in cell survival.

• Journal of Life Science
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• v.33 no.10
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• pp.776-782
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• 2023

Silymarin, which is derived from dried Silybum marianum (milk thistle) seeds and fruits, possesses various beneficial properties, such as hepatoprotective, antioxidative, anti-inflammatory, and anticancer activity. This research aimed to explore the antioxidative activity of silymarin against oxidative stress and understand its molecular mechanism in RAW 264.7 cells. The study employed cell viability and reactive oxygen species (ROS) formation assays and western blot analysis. The results demonstrated that silymarin effectively reduced intracellular ROS levels induced by lipopolysaccharide (LPS) in a dose-dependent manner without causing any cytotoxic effects. Moreover, silymarin treatment significantly upregulated the expression of heme oxygenase (HO)-1, a phase II enzyme known for its potent antioxidative activity. Additionally, silymarin treatment significantly induced the expression of nuclear factor-erythroid 2 p45-related factor (Nrf) 2, a transcription factor responsible for regulating antioxidative enzymes, which was consistent with the upregulated HO-1 expression. To investigate the involvement of key signaling pathways in maintaining cellular redox homeostasis against oxidative stress, the phosphorylation status of mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) was estimated by western blot analysis. The results showed that silymarin potently induced HO-1 expression, which was mediated by the phosphorylation of p38 MAPK. To further validate the antioxidative potential of silymarin-induced HO-1 expression, tert-butyl hydroperoxide (t-BHP)-induced oxidative damage was employed and attenuated by silymarin treatment, as identified by a selective inhibitor for each signaling molecule. In conclusion, silymarin robustly enhanced antioxidative activity by inducing HO-1 via the Nrf2/p38 MAPK signaling pathway in RAW 264.7 cells.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.1
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• pp.1-10
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• 2024

Purpose: Lycopene is abundantly contained in Tomatoes and is known for diverse biological activities such as antioxidant, anti-inflammatory, and anticancer effects. In this study, the antioxidative potential of lycopene was investigated through the induction of hemeoxygenase (HO)-1 by nuclear factor-erythroid 2 p45-related factor2 (Nrf2) and upstream signaling molecules, mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/Aktin RAW 264.7 cells. Methods: The antioxidative potential of lycopene against oxidative stress and its molecular mechanisms were determined by the cell viability assay, intracellular reactive oxygen species (ROS) formation assay, and Western blot analysis in RAW 264.7 cells. Results: Lycopene treatment significantly attenuated tert-butyl hydroperoxide (t-BHP) induced intracellular ROS formation in a dose-dependent manner without any cytotoxicity. In addition, 50 µM of lycopene for 6 h treatment induced potent HO-1 expression and its transcription factor, Nrf2. MAPK and PI3K/Aktwere also analyzed due to their critical roles in the regulation of cellular redox homeostasis against oxidative damage. As a result, phosphorylation of extracellular regulated kinase (ERK) was significantly induced by lycopene treatment while the activated status of c-Jun NH2-terminal kinase (JNK), p38, and Akt, were not given any effect. To confirm the antioxidative mechanism of HO-1 mediated by ERK activation, each selective inhibitor was employed in a protection assay, in which oxidative damage occurred by t-BHP. Lycopene, SnPP, and CoPP treatments reflected accelerated HO-1 expression could be a protective role against oxidative damage-initiated cell death. A selective inhibitor for ERK significantly inhibited the lycopene-induced cytoprotective effect but selective inhibitors for other signaling molecules did not attenuate the rate of t-BHP-induced cell death. Conclusion: In conclusion, lycopene potently scavenged intracellular ROS formation and enhanced the HO-1 mediated antioxidative potential through the modulation of Nrf2, MAPK signaling pathway in RAW 264.7 cells.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.288.3-289
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• 2002

Increasing evidence regarding free radical generating agents and inflammatory processes suggests that accumulation of reactive oxygen species can cause hepatotoxicity. A short-chain analog of lipid hydroperoxide, t-butyl hydroperoxide (t-BHP), can be metabolized to free radical intermediates by cytochrome P-450 in hepatocytes. which in turn can initiate lipid peroxidation, affect cell integrity and result in cell injury. (omitted)

• Proceedings of the Korean Biophysical Society Conference
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• 1998.06a
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• pp.33-33
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• 1998

Oxidation and reduction of amino acid residues in proteins affect their functional properties. Especially, redox modulation of ion channel activities has been reported in number of ion channel proteins. In this study, we investigated the effects of tertiary-butyl hydrogen peroxide (tBHP) on the large-conductance Ca$\^$2＋/ -activated K$\^$+/(Maxi-K) channel of rat brain using lipid bilayer reconstitution technique.(omitted)

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1999.03b
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• pp.34-39
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• 1999

IN this study when drawing a square cup blank holder pressure necessary for flange wrinkling prevention was experimentally studied. The materials used in the experiment were SPCC and SUS304 and drawing ratio was 1.62∼2.0 Two case for lubrication condition were experimented. One was without lubricant and the other was with lubrication of high viscosity.

• Transactions of Materials Processing
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• v.9 no.4
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• pp.356-361
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• 2000

In this study, when a square cup is under drawing, blank holder pressure necessary for flange wrinkling prevention was experimentally studied. The materials used in the experiment were SPCC steel and SUS304 and the drawing ratio was 1.62∼2.0. Two cases for lubricantion condition were investigated. One was without lubricant and the other was with lubricant of high viscosity.

• Bulletin of the Society of Naval Architects of Korea
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• v.24 no.4
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• pp.53-70
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• 1987

The world's largest twin skeg VLBC developed at Samsung shipyard for BHP, Austrailian owner, has been proven as a successful vessel through 1 year's operation record in view of the superior propulsion performances, maneouverability in extremely shallow water and all ship's systems, especially, ship's vibration. The principal technical matter during the design development from the initial design stage to the sea trial has been summarized on this report.