Radicicol Inhibits iNOS Expression in Cytokine-Stimulated Pancreatic Beta Cells

Cha Kyung Youn,Seon Joo Park,Mei Hong Li,Min Young Lee,Kun Yeong Lee,Man Jin Cha,Ok Hyeun Kim,Ho Jin You,In Youp Chang,Sang Pil Yoon,Young Jin Jeon 대한생리학회-대한약리학회 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.4

Here, we show that radicicol, a fungal antibiotic, resulted in marked inhibition of inducible nitric oxide synthase (iNOS) transcription by the pancreatic beta cell line MIN6N8a in response to cytokine mixture (CM: TNF-Ձ, IFN-Ճ, and IL-1Ղ). Treatment of MIN6N8a cells with radicicol inhibited CM-stimulated activation of NF-ՊB/Rel, which plays a critical role in iNOS transcription, in a dose-related manner. Nitrite production in the presence of PD98059, a specific inhibitor of the extracellular signal-regulated protein kinase-1 and 2 (ERK1/2) pathway, was dramatically diminished, suggesting that the ERK1/2 pathway is involved in CM-induced iNOS expression. In contrast, SB203580, a specific inhibitor of p38, had no effect on nitrite generation. Collectively, this series of experiments indicates that radicicol inhibits iNOS gene expression by blocking ERK1/2 signaling. Due to the critical role that NO release plays in mediating destruction of pancreatic beta cells, the inhibitory effects of radicicol on iNOS expression suggest that radicicol may represent a useful anti-diabetic activity.

Crosslinked anion exchange membranes with primary diamine-based crosslinkers for vanadium redox flow battery application

Cha, Min Suc,Jeong, Hwan Yeop,Shin, Hee Young,Hong, Soo Hyun,Kim, Tae-Ho,Oh, Seong-Geun,Lee, Jang Yong,Hong, Young Taik Elsevier 2017 Journal of Power Sources Vol.363 No.-

<P><B>Abstract</B></P> <P>A series of polysulfone-based crosslinked anion exchange membranes (AEMs) with primary diamine-based crosslinkers has been prepared via simple a crosslinking process as low-cost and durable membranes for vanadium redox flow batteries (VRFBs). Chloromethylated polysulfone is used as a precursor polymer for crosslinked AEMs (CAPSU-x) with different degrees of crosslinking. Among the developed AEMs, CAPSU-2.5 shows outstanding dimensional stability and anion (Cl<SUP>−</SUP>, SO<SUB>4</SUB> <SUP>2−</SUP>, and OH<SUP>−</SUP>) conductivity. Moreover, CAPSU-2.5 exhibits much lower vanadium ion permeability (2.72 × 10<SUP>−8</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>) than Nafion 115 (2.88 × 10<SUP>−6</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>), which results in an excellent coulombic efficiency of 100%. The chemical and operational stabilities of the membranes have been investigated via ex situ soaking tests in 0.1 M VO<SUB>2</SUB> <SUP>+</SUP> solution and in situ operation tests for 100 cycles, respectively. The excellent chemical, physical, and electrochemical properties of the CAPSU-2.5 membrane make it suitable for use in VRFBs.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The crosslinking between polymer chains are constructed by 4,4′-diaminobenzophenone. </LI> <LI> The crosslinked AEMs were fabricated by commercial polysulfone (PSU; Udel<SUP>®</SUP> P-3500). </LI> <LI> The crosslinked AEM based on PSU indicated good chemical and dimensional stability. </LI> <LI> The performance of crosslinked AEM showed high EE (86%) with high capacity retention. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Ether-free polymeric anion exchange materials with extremely low vanadium ion permeability and outstanding cell performance for vanadium redox flow battery (VRFB) application

Cha, Min Suc,Jo, Sang Woo,Han, Seung Hui,Hong, Soo Hyun,So, Soonyong,Kim, Tae-Ho,Oh, Seong-Geun,Hong, Young Taik,Lee, Jang Yong Elsevier 2019 Journal of Power Sources Vol.413 No.-

<P><B>Abstract</B></P> <P>Ether-free poly(<I>p</I>-phenylene)-based anion exchange membrane materials with outstanding vanadium ion blocking properties are reported. The synthesized ionomers with a rigid backbone structure show small dimensional variations despite the high ion exchange capacities. Among the synthesized membranes, the QPPP-2 membrane with ion exchange capacity of 2.1 meq·g<SUP>−1</SUP> exhibits high anion (OH<SUP>−</SUP>, SO<SUB>4</SUB> <SUP>2−</SUP>, and Cl<SUP>−</SUP>) conductivity. The QPPP-2 membrane shows an extremely low diffusion coefficient (2.12 × 10<SUP>−9</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>) for VO<SUP>2+</SUP>, which is much lower than that of Nafion 115 (2.88 × 10<SUP>−6</SUP> cm<SUP>2</SUP> min<SUP>−1</SUP>), indicating the vanadium ion blocking property of QPPP-2. Moreover, the chemical and operational stabilities of the membranes are investigated <I>via</I> ex situ soaking tests in 0.1 M VO<SUB>2</SUB> <SUP>+</SUP> solution and in situ operation tests for 100 cycles, respectively. The vanadium redox flow battery single cell assembled with the QPPP-2 membrane exhibits a coulombic efficiency of 99%, voltage efficiency of 87%, and energy efficiency of 86% during 100 cycles at 80 mA cm<SUP>−2</SUP>. The excellent chemical, morphological, and electrochemical properties of the QPPP-2 membrane make it suitable for use in vanadium redox flow battery.</P> <P><B>Highlights</B></P> <P> <UL> <LI> AEMs are fabricated by a Ni(0)-catalyzed cross-coupling reaction. </LI> <LI> The synthesized ionomers indicated excellent dimensional and chemical stability. </LI> <LI> Ether-free polymeric AEMs showed extremely low vanadium ion cross over. </LI> <LI> The performance of developed AEM showed high EE (87%) with high capacity retention. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Radicicol Inhibits iNOS Expression in Cytokine-Stimulated Pancreatic Beta Cells

Youn, Cha Kyung,Park, Seon Joo,Li, Mei Hong,Lee, Min Young,Lee, Kun Yeong,Cha, Man Jin,Kim, Ok Hyeun,You, Ho Jin,Chang, In Youp,Yoon, Sang Pil,Jeon, Young Jin The Korean Society of Pharmacology 2013 The Korean Journal of Physiology & Pharmacology Vol.17 No.4

Here, we show that radicicol, a fungal antibiotic, resulted in marked inhibition of inducible nitric oxide synthase (iNOS) transcription by the pancreatic beta cell line MIN6N8a in response to cytokine mixture (CM: TNF-${\alpha}$, IFN-${\gamma}$, and IL-$1{\beta}$). Treatment of MIN6N8a cells with radicicol inhibited CM-stimulated activation of NF-${\kappa}B$/Rel, which plays a critical role in iNOS transcription, in a dose-related manner. Nitrite production in the presence of PD98059, a specific inhibitor of the extracellular signal-regulated protein kinase-1 and 2 (ERK1/2) pathway, was dramatically diminished, suggesting that the ERK1/2 pathway is involved in CM-induced iNOS expression. In contrast, SB203580, a specific inhibitor of p38, had no effect on nitrite generation. Collectively, this series of experiments indicates that radicicol inhibits iNOS gene expression by blocking ERK1/2 signaling. Due to the critical role that NO release plays in mediating destruction of pancreatic beta cells, the inhibitory effects of radicicol on iNOS expression suggest that radicicol may represent a useful anti-diabetic activity.

Antioxidant and cytoprotective effects of morin against hydrogen peroxide-induced oxidative stress are associated with the induction of Nrf-2-mediated HO-1 expression in V79-4 Chinese hamster lung fibroblasts

Lee, Moon Hee,Cha, Hee-Jae,Choi, Eun Ok,Han, Min Ho,Kim, Sung Ok,Kim, Gi-Young,Hong, Su Hyun,Park, Cheol,Moon, Sung-Kwon,Jeong, Soon-Jeong,Jeong, Moon-Jin,Kim, Wun-Jae,Choi, Yung Hyun Spandidos Publications 2017 International journal of molecular medicine Vol.39 No.3

<P>Natural phytochemicals of plant origin, including flavonoids, have been found to be potent antioxidants providing beneficial effects against oxidative stress-related diseases. The present study was carried out to investigate the antioxidant properties of morin, a flavonoid originally isolated from the flowering plants of the Moraceae family. Superoxide dismutase (SOD)-like activity and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(center dot+)) radical scavenging activity were determined. We also investigated the cytoprotective effects of morin against hydrogen peroxide (H2O2)-induced DNA damage and apoptosis in V79-4 Chinese hamster lung fibroblasts. Our results demonstrated that morin had strong scavenging effects against ABTS' radicals with enhanced SOD activity, which varied in a dose-dependent manner. Morin was found to reduce H2O2-induced intracellular reactive oxygen species generation and nuclear DNA damage, and it recovered cell viability damaged by H2O2 via inhibition of mitochondrial dysfunction-mediated apoptosis. Notably, the treatment of V79-4 cells with morin markedly enhanced the expression of heme oxygenase-1 (HO-1) but not quinone oxidoreductase-1, which was associated with the increased expression and phosphorylation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and the downregulation of Kelch-like ECH-associated protein 1 expression. Based on our findings, we conclude that morin effectively ameliorated oxidative stress-induced DNA damage through intrinsic free radical scavenging activity and activation of the Nrf2/HO-1 pathway.</P>

Morin exerts cytoprotective effects against oxidative stress in C2C12 myoblasts via the upregulation of Nrf2-dependent HO-1 expression and the activation of the ERK pathway

Lee, Moon Hee,Han, Min Ho,Lee, Dae-Sung,Park, Cheol,Hong, Su-Hyun,Kim, Gi-Young,Hong, Sang Hoon,Song, Kyoung Seob,Choi, Il-Whan,Cha, Hee-Jae,Choi, Yung Hyun UNKNOWN 2017 INTERNATIONAL JOURNAL OF MOLECULAR MEDICINE Vol.39 No.2

<P>In the present study, we investigated the cytoprotective efficacy of morin, a natural flavonoid, against oxidative stress and elucidated the underlying mechanisms in C2C12 myoblasts. Our results indicated that morin treatment prior to hydrogen peroxide (H2O2) exposure significantly increased cell viability and prevented the generation of reactive oxygen species. H2O2-induced comet-like DNA formation and gamma H2AX phosphorylation were also markedly suppressed by morin with a parallel inhibition of apoptosis in C2C12 myoblasts, suggesting that morin prevented H2O2-induced cellular DNA damage. Furthermore, morin markedly enhanced the expression of heme oxygenase-1 (HO-1) associated with the induction and phosphorylation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and the inhibition of Kelch-like ECH-associated protein 1 (Keapl) expression. Notably, these events were eliminated by transient transfection with Nrf2-specific small interfering RNA. Additional experiments demonstrated that the activation of the Nrf2/HO-1 pathway by morin was mediated by the extracellular signal-regulated kinase (ERK) signaling cascade. This phenomenon was confirmed with suppressed Nrf2 phosphorylation and consequently diminished HO-1 expression in cells treated with a pharmacological inhibitor of ERK. Collectively, these results demonstrated that morin augments the cellular antioxidant defense capacity through the activation of Nrf2/HO-1 signaling, which involves the activation of the ERK pathway, thereby protecting C2C12 myoblasts from H2O2,-induced oxidative cytotoxicity.</P>

Anti-Proliferative Effect of an Aqueous Extract of <i>Prunella vulgaris</i> in Vascular Smooth Muscle Cells

Hwang, Sun Mi,Lee, Yun Jung,Lee, Yong Pyo,Yoon, Jung Joo,Lee, So Min,Cha, Jeong Dan,Choi, Kyung Min,Kang, Dae Gill,Lee, Ho Sub Hindawi Publishing Corporation 2013 Evidence-based Complementary and Alternative Medic Vol.2013 No.-

<P>The abnormal proliferation of vascular smooth muscle cells (VSMCs) in arterial walls is an important pathogenic factor of vascular disorders such as diabetic atherosclerosis. We have reported the anti-inflammatory effect of an aqueous extract from <I>Prunella vulgaris</I> (APV) in vascular endothelial cell. In the present study, APV exhibited inhibitory effects on high glucose-stimulated VSMC proliferation, migration, and invasion activities, inducing G<SUB>1</SUB> cell cycle arrest with downregulation of cyclins and CDKs and upregulation of the CKIs, p21<SUP>waf1/cip1</SUP> and p27<SUP>kip1</SUP>. Furthermore, APV dose dependently suppressed the high glucose-induced matrix metalloproteinase activity. High glucose-induced phosphorylation of ERK, p38 MAPK, was decreased by the pretreatment of APV. NF-<I><I>κ</I></I>B activation by high glucose was attenuated by APV, as an antioxidant. APV attenuated the high glucose-induced decrease of nuclear factor E2-related factor-2 (Nrf2) translocation and heme oxygenase-1 (HO-1) expression. Intracellular cGMP level was also increased by APV treatment. These results demonstrate that APV may inhibit VSMC proliferation via downregulating ROS/NF-<I><I>κ</I></I>B /ERK/p38 MAPK pathways. In addition, APV has a beneficial effect by the interaction of Nrf2-mediated NO/cGMP with HO-1, suggesting that <I>Prunella vulgaris</I> may be useful in preventing diabetic atherosclerosis.</P>

GHP용 천연가스 엔진의 희박 연소 특성에 관한 연구

李珉湖,李焌瑞,車京玉 明知大學校 産業技術硏究所 2004 産業技術硏究所論文集 Vol.23 No.-

Lean burn in natural gas spark ignition engine is the effective way to achieve energy saving and low emission effects. The keys techniques for the lean burn considered as followings ; test technique for intake port performance, measurement and analysis of in-cylinder air motion, flame propagation measurement, and finding correlation between fluid motion and flame speed. In other advanced countries, these techniques had been fully developed and have been applying to engine production, but the domestic technology and/or know-how for lean burn engine design are not enough. This study aims to develope fundamental key techniques for the lean burn in natural gas engine for GHP. The techniques in this study include intake port design (SCV) and test method. Experimental is applied to investigate the effects of swirl control valves to improve the engine performance and emission, efficiency in a DOHC natural gas engine using the GHP engine.

연료 변화에 따른 고압 스월 인젝터의 연료분무 특성

李珉湖,李焌瑞,車京玉 明知大學校 産業技術硏究所 2004 産業技術硏究所論文集 Vol.23 No.-

In comparison with gasoline engine, LPG direct injection engine can have advantage in emission and fuel efficiency, and solve the problems which conventional LPG engine has, like power decrease and back fire etc. So, Direct injection engine technology is applied to LPG engine, it can show the solution of ULEV emission regulation. In this paper, the in-cylinder spray characteristics of LPG fuel has been studied in the CVC as a preliminary research for the development of low emission and high fuel efficiency of LPG engine in near future. During the direct injection of LPG fuel into the inside of CVC, both droplet development and vaporization characteristics according to the injection condition have been photographed by the high speed shadow graph and schlieren methods. The results are compared with the case of gasoline fuel.

GHP용 엔진의 개발 연구 (Ⅰ) : 저속·고출력 천연가스 엔진의 개발 The Development of Low speed·High Power Natural Gas Engine

이민호,차경옥 明知大學校 産業技術硏究所 2003 産業技術硏究所論文集 Vol.22 No.-

GHP, operated by gas instead of electrical motor, has there is better energy saving 20% comparing with EHP(electrical motor-driven heat pump) by using the exhaust heat from the engine effectively. This means that GHP has an advantage in the reduction of CO_2 which causes main greenhouse effects. Natural gas is one of the most promising alternative fuels for automotive vehicles, because it has lower exhaust emissions and better fuel economy characteristics than gasoline, diesel, LPG and can be used in conventional engine with a little modifications. Natural gas engine for GHP should be mostly based on 4 stroke water-cooled diesel engine which has high power in low speed, but sometimes could be based on automotive LPG engines because of easy modification. In this paper, a conventional LPG engine was modified to a NG dedicated engine, which can be operated with NG only, and a engine bench test was performed at various experimental condition. As a result, it was revealed that the prototype NG engine can be operated with lower exhaust emissions, better fuel economy and better thermal efficiency, but with a slightly reduced brake horse power, compared to the conventional LPG engine.