• Proceedings of the Korean Society of Food Science and Nutrition Conference
• /
• 2004.11a
• /
• pp.265-270
• /
• 2004

Coronary heart disease (CHD) has been the number one killer in western society for a long time, and CHD in most instances is due to atherosclerosis. One of the earliest events in atherogenesis is the intracellular accumulation of lipids, particularly cholesterol esters, in the aortic intima. The lipids presumably came from the uptake of plasma lipoproteins, particularly from LDL. These foam cells were identified as being predominantly as macrophages. Currently, it is believed that oxidation of low density lipoprotein (LDL) might contribute to the generation of foam cells. An outcome of the oxidation hypothesis is that the consumption of antioxidants would be beneficial. In this study, Boldine, an alkaloid of Peumus boldus was tested for their antioxidant potency both in, in vitro oxidation system and in mouse models. Boldine decreased the ex-vivo oxidation of Low-density lipoprotein (LDL). In vivo studies were performed to study the effect of these compounds on the atherosclerotic lesion formation in LDL r-/- mice. Three groups of LDL r-/- mice (N=12 each) were fed an atherogenic diet. Group 1 was given vehicle and group 2 and 3 were given 1 and 5 mg of Boldine/day in addition to the atherogenic diet. The results indicated that there was a decrease in lesion formation reaching a 40% reduction due to Boldine compared to controls. The in vivo tolerance of Boldine in humans (has been used as an herbal medicine in other diseases) should make it an attractive alternative to vitamin E.

• Proceedings of the KSAR Conference
• /
• 2000.10a
• /
• pp.3-4
• /
• 2000

The synthesis of acyl-CoA catalyzed by acyl-CoA synthetase (ACS, EC 6.2.1.3) from fatty acid, ATP, and CoA is a crucial reaction in mammalian fatty acid metabolism. In arachidonate metabolism, acyl-CoA synthetase(ACS) plays a key role in the esterification of free arachidonate into membrane phospholipids. Following its release by the action of calcium dependent phospholipase, free arachidonate is believed to be rapidly converted to arachidonoyl-CoA and reesterified into phospholipids in order to prevent excessive synthesis of eicosanoids. In previous studies, we have characterized five ACSs (designated as ACS1-5) with different tissue distribution. ACS1, ACS2, and ACS5 are similar in structure and fatty acid preference, and completely different from ACS3 and ACS4. The latter are arachidonate-preferring enzymes closely related in structure but expressed in different tissues: ACS3 mRNA is highly expressed in the brain and the mRNA for ACS4 is expressed in steroidogenic tissues including adrenal gland, ovary, and testis. To learn more about the potential function of ACS4 in arachidonate metabolism, we have produced knock-out mice for ACS4 gene. ACS4+/- females become pregnant less frequently and produce small litters with extremely low transmission of the disrupted alleles. Striking morphological changes including extremely enlarged uterine filled with numerous proliferative cysts of various size were detected in ACS4+/- females. Furthermore, marked accumulation of prostaglandins were seen in the uterus of heterozygous females. These results indicate that ACS4 is critical for the uterine arachidonate metabolism and heterozygous disruption of its gene lead to impaired pregnancy.

• IMMUNE NETWORK
• /
• v.9 no.6
• /
• pp.274-284
• /
• 2009

Background: Swiprosin-1 was identified in human CD8+ lymphocytes, mature B cells and non-lymphonoid tissue. We have recently reported that swiprosin-1 is expressed in mast cells and up-regulated in both in vitro and in vivo. Methods: The expression of cytokines and swiprosin-1 were determined by by real time PCR and conventional PCR. Pharmacological inhibitors were treated to investigate potential mechanism of swiprosin-1 in mast cell activation. Actin content was evaluated by confocal microscopy and flow cytometry. Results: The swiprosin-1 augmented PMA/A23187-induced expression of cytokines and release of histamine. However, knock-down of swiprosin-1 showed only a modest effect on PMA/A23187-induced cytokine expression, suggesting that swiprosin-1 has gain-of-function characteristics. Swiprosin-1 was found in microvilli-like membrane protrusions and highly co-localized with F-actin. Importantly, either disruption of actin by cytochalasin B or inhibition of PI3 kinase, an enzyme involved in actin remodeling, by wortmannin blocked cytokine expression only in swiprosin-1-overexpressing cells. Conclusion: These results suggest that swiprosin-1 modulates mast cell activation potentially through actin regulation.

• Nutrition Research and Practice
• /
• v.4 no.6
• /
• pp.455-461
• /
• 2010

The tumor microenvironment, particularly sufficient nutrition and oxygen supply, is important for tumor cell survival. Nutrition deprivation causes cancer cell death. Since apoptosis is a major mechanism of neuronal loss, we explored neuronal apoptosis in various microenvironment conditions employing neuroblastoma (NB) cells. To investigate the effects of tumor malignancy and differentiation on apoptosis, the cells were exposed to poor microenvironments characterized as serum-free, low-glucose, and hypoxia. Incubation of the cells in serum-free and low-glucose environments significantly increased apoptosis in less malignant and more differentiated N-type IMR32 cells, whereas more malignant and less differentiated I-type BE(2)C cells were not affected by those treatments. In contrast, hypoxia (1 % $O_2$) did not affect apoptosis despite cell malignancy. It is suggested that DLK1 constitutes an important stem cell pathway for regulating self-renewal, clonogenicity, and tumorigenicity. This raises questions about the role of DLK1 in the cellular resistance of cancer cells under poor microenvironments, which cancer cells normally encounter. In the present study, DLK1 overexpression resulted in marked protection from apoptosis induced by nutrient deprivation. This in vitro model demonstrated that increasing severity of nutrition deprivation and knock-down of DLK1 caused greater apoptotic death, which could be a useful strategy for targeted therapies in fighting NB as well as for evaluating how nutrient deprived cells respond to therapeutic manipulation.

• BMB Reports
• /
• v.53 no.7
• /
• pp.385-390
• /
• 2020

Inflammatory Bowel Disease is caused by an acute or chronic dysfunction of the mucosal inflammatory system in the intestinal tract. In line with the results of our previous study, wherein we found that the PKCα-LSD1-NF-κB signaling plays a critical role in the prolonged activation of the inflammatory response, we aimed to investigate the effect of signaling on colitis in the present study. Lsd1 S112A knock-in (Lsd1^SA/SA) mice, harboring a deficiency in phosphorylation by PKCα, exhibited less severe colitis symptoms and a relatively intact colonic epithelial lining in dextran sulfate sodium (DSS)-induced colitis models. Additionally, a reduction in pro-inflammatory gene expression and immune cell recruitment into damaged colon tissues in Lsd1^SA/SA mice was observed upon DSS administration. Furthermore, LSD1 inhibition alleviated colitis symptoms and reduced colonic inflammatory responses. Both LSD1 phosphorylation and its activity jointly play a role in the progression of DSS-induced colitis. Therefore, the inhibition of LSD1 activity could potentially protect against the colonic inflammatory response.

• The Korean Journal of Physiology and Pharmacology
• /
• v.19 no.6
• /
• pp.515-522
• /
• 2015

Notch signaling is a key regulator of neuronal fate during embryonic development, but its function in the adult brain is still largely unknown. Mind bomb-2 (Mib2) is an essential positive regulator of the Notch pathway, which acts in the Notch signal-sending cells. Therefore, genetic deletion of Mib2 in the mouse brain might help understand Notch signaling-mediated cell-cell interactions between neurons and their physiological function. Here we show that deletion of Mib2 in the mouse brain results in impaired hippocampal spatial memory and contextual fear memory. Accordingly, we found impaired hippocampal synaptic plasticity in Mib2 knock-out (KO) mice; however, basal synaptic transmission did not change at the Schaffer collateral-CA1 synapses. Using western blot analysis, we found that the level of cleaved Notch1 was lower in Mib2 KO mice than in wild type (WT) littermates after mild foot shock. Taken together, these data suggest that Mib2 plays a critical role in synaptic plasticity and spatial memory through the Notch signaling pathway.

• Molecules and Cells
• /
• v.42 no.1
• /
• pp.67-78
• /
• 2019

Methylation of HBV cccDNA has been detected in vivo and in vitro; however, the mechanism and its effects on HBV replication remain unclear. HBx derived from a 1.2-mer HBV replicon upregulated protein levels and enzyme activities of DNA methyltransferase 1 (DNMT1), 3a, and 3b, resulting in methylation of the negative regulatory region (NRE) in cccDNA, while none of these effects were observed with an HBx-null mutant. The HBx-positive HBV cccDNA expressed higher levels of HBc and produced about 4-fold higher levels of HBV particles than those from the HBx-null counterpart. For these effects, HBx interrupted the action of NRE binding protein via methylation of the C-1619 within NRE, resulting in activation of the core promoter. Treatment with 5-Aza-2′dC or DNMT1 knock-down drastically impaired the ability of HBx to activate the core promoter and stimulate HBV replication in 1.2-mer HBV replicon and in vitro infection systems, indicating the positive role of HBx-mediated cccDNA methylation in HBV replication.

• BMB Reports
• /
• v.49 no.7
• /
• pp.394-399
• /
• 2016

Glioma-Associated Oncogene Homolog1 (Gli1) is known to be activated in malignant glioma; however, its downstream pathway has not been fully explained. The aim of this study was to explore the role of Gli1-Aquaporin1 (AQP1) signal pathway in glioma cell survival. Our data suggests that both Gli1 and AQP1 are upregulated in glioma tissues, as in comparison to in normal tissues. These up-regulation phenomena were also observed in glioma U251 and U87 cells. It was demonstrated that Gli1 positively regulated the AQP1 expression. By luciferase reporter gene and ChIP assay, we observed that this modulation process was realized by combination of Gli1 with AQP1 promotor. In addition, knock down of Gli1 by siRNA interference reduced the viability of glioma cells as well as suppressed cell metastasis. Also, the inhibitory effects of cell survival by silenced Gli1 were abrogated by AQP1 overexpression. In summary, glioma cell survival is a regulatory process and can be mediated by Gli1-AQP1 pathway.

• Asian-Australasian Journal of Animal Sciences
• /
• v.30 no.7
• /
• pp.944-949
• /
• 2017

Objective: Investigated the effect and mechanism of ascorbic acid on the development of porcine embryos produced by somatic cell nuclear transfer (SCNT). Methods: Porcine embryos were produced by SCNT and cultured in the presence or absence of ascorbic acid. Ten-eleven translocation 3 (TET3) in oocytes was knocked down by siRNA injection. After ascorbic acid treatment, reprogramming genes were analyzed by realtime reverse transcription-polymerase chain reaction (RT-PCR). Furthermore, relative 5-methylcytosine and 5-hydroxymethylcytosine content in pronucleus were detected by realtime PCR. Results: Ascorbic acid significantly increased the development of porcine embryos produced by SCNT. After SCNT, transcript levels of reprogramming genes, Pou5f1, Sox2, and Klf were significantly increased in blastocysts. Furthermore, ascorbic acid reduced 5-methylcytosine content in pronuclear embryos compared with the control group. Knock down of TET3 in porcine oocytes significantly prevents the demethylation of somatic cell nucleus after SCNT, even if in the presence of ascorbic acid. Conclusion: Ascorbic acid enhanced the development of porcine SCNT embryos via the increased TET3 mediated demethylation of somatic nucleus.

• BMB Reports
• /
• v.52 no.7
• /
• pp.451-456
• /
• 2019

NDRG1 has been reported to exert pivotal roles in tumor progression and metastasis via Wnt/${\beta}$-catenin signaling pathway. However, little is known about the role of NDRG3 in hepatocarcinogenesis despite its classification in the same subfamily of NDRG1. The present study was aimed to characterize the expression pattern and understand the biological roles of NDRG3 in hepatocarcinogenesis, as a means to exploit its therapeutic potential. It was observed that NDRG3 was up-regulated in HCC tissues and higher NDRG3 expression was associated with significantly shorter overall survival. Furthermore, a lower level of NDRG3 exhibited marked positive correlation with metastasis-free survival. In vitro and in vivo experiments revealed that knock-down of NDRG3 inhibits HCC metastasis and angiogenesis. We further demonstrated that activation of WNT/${\beta}$-catenin signaling and enhanced CSC-like properties were responsible for NDRG3-mediated promoting effect on HCC. In conclusion, the principal findings demonstrated that high NDRG3 expression facilitates HCC metastasis via regulating the turnover of ${\beta}$-catenin, as well as provides a potential therapeutic target for future therapeutic interventions.