• Journal of Life Science
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• v.28 no.2
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• pp.162-169
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• 2018

Many cytoplasmic proteins are targeted to the cytoplasmic membrane of the trans-Golgi network (TGN) via an N-terminal short helix. We previously showed that the 20 N-terminal amino acids of Aplysia phosphodiesterase 4 (ApPDE4) long form are sufficient for its targeting to the plasma membrane and the TGN. The N-terminus of the ApPDE4 long form binds to PI4P and sulfatide in vitro. Therefore, in order to decipher the roles of sulfatide in Golgi complex targeting, we examined the cellular localization of sulfatide-binding peptides. In this study, we found that enhanced green fluorescent protein (EGFP) fused to the C-terminus of modified sulfatide- and heparin-binding peptides (mHSBP-EGFP) was localized to the TGN. On the other hand, its mutant, in which tryptophan was replaced with an alanine, leading to the impairment of heparin and sulfatide binding, was localized to cytosol. We also found that the TGN targeting of mHSBP-EGFP is impaired by the treatment of antimycin A, phenylarsine oxide (PAO), and adenosine but not a high concentration of wortmannin. These results suggest that PAO and adenosine-sensitive kinases, including phosphatidylinositol 4-kinase II, may play key roles in the recruitment of mHSBP-EGFP.

• Journal of Food Hygiene and Safety
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• v.33 no.4
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• pp.316-323
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• 2018

The purpose of the present study was to investigate the effect of Salvia Plebia R. Br. (SP) powder on the antioxidative defense system and oxidative stress in rats which were fed a high fat high cholesterol diet. Accordingly, the rats were divided into four experimental groups which were composed of a high fat high cholesterol diet group (HF), HF diet with 5% SP powder supplemented group (PA), a HF diet with 10% SP powder supplemented group (PB), and a normal group (N). Consequently, the hepatic catalase activity of the HF group was decreased compared to the normal group (N), but it is recorded that of the PA and PB groups were significantly increased. With this in mind, the PA and PB groups resulted in the case of significantly increased activities of hepatic GSH-px and SOD. The hepatic superoxide radical and hydrogen peroxide contents of the PA and PB groups were significantly decreased, as compared to the HF group. The GOT and GPT activities of the PB group were also significantly decreased when thus compared to the HF group. Notably, the carbonyl values contents of the PA and PB groups were significantly reduced compared to the HF group. The hepatic TBARS values in the liver were significantly reduced as measured in the PA and PB groups. These results suggest that the SP powder may reduce the incidence of oxidative damage, by the activation of an antioxidative enzyme in rats fed with high fat high cholesterol diets.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.4
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• pp.239-246
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• 2005

In the central nervous system, nitric oxide (NO) is associated with many pathological diseases such as brain ischemia, neurodegeneration and inflammation. The epigallocatechin gallate (EGCG), a major compound of green tea, is recognized as protective substance against neuronal diseases. This study is aimed to investigate the effect of EGCG on NO-induced cell death in PC12 cells. Administration of sodium nitroprusside (SNP), a NO donor, decreased cell viability in a dose- and time-dependent manner and induced genomic DNA fragmentation with cell shrinkage and chromatin condensation. EGCG diminished the decrement of cell viability and the formation of apoptotic morphologenic changes as well as DNA fragmentation by SNP. EGCG played as an antioxidant that attenuated the production of reactive oxygen species (ROS) by SNP. The cells treated with SNP showed downregulation of Bcl-2, but upregulation of Bax. EGCG ameliorated the altered expression of Bcl-2 and Bax by SNP. The release of cytochrome c from mitochondria into cytosol and expression of voltage -dependent anion channel (VDAC)1, a cytochrome c releasing channel in mitochondria, were increased in SNP-treated cells, whereas were attenuated by EGCG. The enhancement of caspase-9, preceding mitochondria-dependent pathway, caspase-8 and death receptor-dependent pathway, as well as caspase-3 activities were suppressed by EGCG. SNP upragulated Fas and Fas-L, which are death receptor assembly, whereas EGCG ameliorated the expression of Fas enhanced by SNP. These results demonstrated that EGCG has a protective effect against SNP-induced apoptosis in PC12 cells, through scavenging ROS and regulating the mitocondria- and death receptor-mediated signal pathway. The present study suggest that EGCG might be a natural neuroprotective substance.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.1
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• pp.33-39
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• 2002

It has been suggested that $Ca^{2+}$ sensitization mechanisms might contribute to myogenic tone, however, specific mechanisms have not yet been fully identified. Therefore, we investigated the role of protein kinase C (PKC)- or RhoA-induced $Ca^{2+}$ sensitization in myogenic tone of the rabbit basilar vessel. Myogenic tone was developed by stretch of rabbit basilar artery. Fura-2 $Ca^{2+}$ signals, contractile responses, PKC immunoblots, translocation of PKC and RhoA, and phosphorylation of myosin light chains were measured. Stretch of the resting vessel evoked a myogenic contraction and an increase in the intracellular $Ca^{2+}$ concentration $([Ca^{2+}]_i)$ only in the presence of extracellular $Ca^{2+}$. Stretch evoked greater contraction than high $K^+$ at a given $[Ca^{2+}]_i.$ The stretch-induced increase in $[Ca^{2+}]_i$ and contractile force were inhibited by treatment of the tissue with nifedipine, a blocker of voltage-dependent $Ca^{2+}$ channel, but not with gadolinium, a blocker of stretch-activated cation channels. The PKC inhibitors, H-7 and calphostin C, and a RhoA-activated protein kinase (ROK) inhibitor, Y-27632, inhibited the stretch-induced myogenic tone without changing $[Ca^{2+}]_i.$ Immunoblotting using isoform-specific antibodies showed the presence of $PKC_{\alpha}$ and $PKC_{\varepsilon}$ in the rabbit basilar artery. $PKC_{\alpha},$ but not $PKC_{\varepsilon},$ and RhoA were translocated from the cytosol to the cell membrane by stretch. Phosphorylation of the myosin light chains was increased by stretch and the increased phosphorylation was blocked by treatment of the tissue with H-7 and Y-27632, respectively. Our results are consistent with important roles for PKC and RhoA in the generation of myogenic tone. Furthermore, enhanced phosphorylation of the myosin light chains by activation of $PKC_{\alpha}$ and/or RhoA may be key mechanisms for the $Ca^{2+}$ sensitization associated with myogenic tone in basilar vessels.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.613-618
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• 2016

1,2,3,4,6-Penta-O-galloyl-${\beta}$-D-glucose (PGG) is a gallotannin isolated from various plants such as Galla Rhois. In a previous study, it was reported that PGG has anti-allergic effects by inhibiting interleukin (IL)-4 signaling in B cells. However, the effect of PGG on basophilic cells remains unclear. Therefore, the aim of this study was to investigate the inhibitory effect of PGG on mitogen and calcium ionophore-induced allergic responses. PGG had no effect on proliferation and cytotoxicity of RBL-2H3 cells. PGG significantly suppressed cell degranulation (histamine and ${\beta}-hexosaminidase$) as well as inflammatory cytokine production such as IL-4 and tumor necrosis factor-${\alpha}$. The underlying mechanism of PGG on these anti-allergic actions was correlated with inhibition on translocation of nuclear factor-${\kappa}B$ from the cytosol to nucleus. These data suggest that PGG is a potentially effective functional compound for prevention of allergic diseases.

• Journal of Life Science
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• v.25 no.9
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• pp.984-992
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• 2015

Sanguinarine is a benzophenanthridine alkaloid originally isolated from the roots of Sanguinaria canadensis. It has multiple biological activities (e.g., antioxidant and antiproliferative) and immune-enhancing potential. In this study, we explored the proapoptotic properties and modes of action of sanguinarine in human hepatocellular carcinoma HepG2 cells. Our results revealed that sanguinarine inhibited HepG2 cell growth and induced apoptosis in a dose-dependent manner. The induction of apoptosis by sanguinarine was associated with the up-regulation of Fas and Bax, the release of cytochrome c from the mitochondria to the cytosol, and the loss of the mitochondrial membrane potential. In addition, sanguinarine activated caspase-9 and -8, initiator caspases of the intrinsic and death extrinsic pathways, respectively, and caspase-3, accompanied by proteolytic degradation of poly (ADP-ribose) polymerase. Sanguinarine also triggered the generation of reactive oxygen species (ROS). The elimination of ROS by N-acetylcysteine reversed sanguinarine-induced apoptosis. Furthermore, sanguinarine induced the dephosphorylation of Akt and the phosphorylation of mitogen-activated protein kinases, including extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), and p38. The growth inhibition was enhanced by the combined treatment of sanguinarine with a phosphatidylinositol 3'-kinase (PI3K) inhibitor and an ERK inhibitor but not JNK and p38 inhibitors. Overall, our data indicate that the proapoptotic effects of sanguinarine in HepG2 cells depend on ROS production and the activation of both intrinsic and extrinsic signaling pathways, which is mediated by blocking PI3K/Akt and activating the ERK pathway. Thus, our data suggest that sanguinarine may be a natural compound with potential for use as an antitumor agent in liver cancer.

• Journal of Life Science
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• v.24 no.10
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• pp.1055-1062
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• 2014

We investigated the expression of cucumber genes involved in lipid mobilization and metabolism during cotyledon development to compare gene activity and to study the direction of carbon (acetyl unit) transport between glyoxysomes and mitochondria. The core metabolic pathway involving 10 genes was examined in four intracellular compartments: glyoxysomes (peroxisomes), mitochondria, chloroplasts, and cytosol. Additionally, we tested the early germination response of dark-grown seedlings and the immediate light response for a further 3 days. According to the reverse transcription polymerase chain reaction (RT-PCR), 3-L-ketoacyl-CoA thiolase 2 (Thio2), isocitrate lyase (ICL), and malate synthase (MS), the genes involved in storage lipid mobilization showed a similar and consistent pattern of gene expression in seedling development. Furthermore, coordinate expression of the A BOUT DE SOUFFLE (BOU) gene with ICL and MS during seedling emergence pointed to a possible secondary route of acetyl unit (acetyl-CoA) transport between peroxisomes and mitochondria in cucumber. The expression of the BOU gene was light dependent, as shown by BOU activity in Arabidopsis, suggesting that the dark condition also results in weak membrane biogenesis. In addition, several genes were active throughout the development of the green cotyledon, even during senescence. In conclusion, this study summarizes oil-seed germination and gene expression during cucumber cotyledon development and proposes an additional route for acetyl unit transport.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.1055-1060
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• 2004

Apoptosis is the ability of cells to self-destruct by the activation of an intrinsic cellular suicide program when the cells are no longer needed or when they are seriously damaged. Morphologically, apoptosis is characterized by the appearance of membrane blebbing, cell shrinkage, chromatin condensation, DNA cleavage, and the fragmentation of the cell membrane-bound apoptotic bodies. Siegesbeckia glabrescens Makino (Siegesbeckiae Herba, SG) has been widely used as treatments for arthritis, and fever, as well as detoxification properties. The present studies were undertaken to evaluate if SG has an anti-apoptotic property. Cell viability was measured by XTT and tryphan blue stain. Morphological characteristic of human aortic smooth muscle cells(HASMC) were visualized with a phase-contrast microscope. SG significantly reduced HASMC, but not human umbilical vein endothelial cell(HUVEC), viability in a dose-dependent manner. Confluent untreated cells at 24hrs showed normal morphology, flat with a uniform polygonal shape. SG-treated cells (0.5㎎/㎖) at 24hrs showed apoptotic morphology. Cells became irregular with elongated lamellipodia, and exhibited condensed chromatin in nuclei with occasional endoucleation. There was an increase in the number of apoptotic cells rounding-up and being detached from the substrate. TUNEL staining of SG-treated cells showed dark-brown stains in nuclei and cytosol. Caspases are central components of the machinery responsible for apoptosis and are generally divided into two categories; the initiator caspases, which include caspases-2,-8,-9, and -10, and the effector caspases, which include caspases-3,-6, and -7. SG decreased anti-caspase-3 protein expression, which means activation of caspases-3 activity. It has been reported that there is a link between NO formation and apoptosis. NO production was accelerated by SG treatment in HASMC. L-NNA, NOS inhibitor, inhibited SG-induced apoptosis. These results, therefore, indicated that both caspases-3 and NO production are involved in apoptosis in smooth muscle cells. According to these results, SG may have a potential effect in the treatment of hypertensive atherosclerosis.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.5
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• pp.602-610
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• 2013

This study was aimed to evaluate the cavernosal relaxation effect of Crataegii fructus(CF) in the contracted rabbit penile corpus cavernosum by agonists.In order to study the effect of CF on the vasoconstriction of rabbit penile corpus cavernosum, isolated rabbit penile corpus cavernosum tissues were used for the experiment using organ baths containing Krebs solution.To investigate the cavernosal relaxation of CF, CF extract at $0.01{\sim}3.0mg/m{\ell}$ was added after penile corpus cavernosum were contracted by norepinephrine(NE) $1{\mu}M$. To analyze the mechanism of CF's vasorelaxation, CF extract infused into contracted penile tissues by NE after each treatment of indomethacin(IM), $N{\omega}$-nitro-L-arginine(L-NNA), methylene blue(MB), tetraethylammonium chloride(TEA).To study the effect of CF on influx of extracellular calcium chloride($Ca^{2+}$) in penile tissues, in $Ca^{2+}$-free krebs solution, $Ca^{2+}$ 1 mM infused into contracted penile tissues by NE after pretreatment of CF. Cytotoxic activity of CF on human umbilical vein endothelial cell(HUVEC) was measured by MTT assay, and nitric oxide(NO) prodution was measured by Griess reagent. CF relaxed cavernosal strip with endothelium contracted by NE, but in the strips without endothelium, CF-induced relaxation was significantly inhibited. The pretreatment of L-NNA, MB, TEA decreased significantly on the cavernosal relaxation than not-treatment of them. But the pretreatment of IM had no significant effect on the cavernosal relaxation. In $Ca^{2+}$-free krebs solution, when $Ca^{2+}$ infused into contracted penile tissues by NE, pretreatment of CF inhibit contraction induced by adding $Ca^{2+}$.NO production wasn't increased by treatment of CF on HUVEC. This findings showed that CF is effective for the relaxation of rabbit penile corpus cavernosum, and we suggest that CF relax rabbit corpus cavernosal smooth muscle through multiple action mechanisms that include increasing the release of nitric oxide from corporal sinusoidal endothelium, inhibition of $Ca^{2+}$ mobilization into cytosol from the extracellular fluid, and maybe a hyperpolarizing action.

• Journal of Physiology & Pathology in Korean Medicine
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• v.27 no.1
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• pp.43-48
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• 2013

Cisplatin is a anti-neoplastic agent which is commonly used for the treatment of solid tumor. Cisplatin activates multiple signal transduction pathways involved in the stress-induced apoptosis in a variety of cell types. Previous study reported that cisplatin induces apoptosis through activation of ERK, p38 and JNK in rat mesangial cells, but apoptotic pathway remain known. The present study investigated the apoptotic pathway for cisplatin-indcued apoptosis in rat mesangial cells. cisplatin-induced apoptosis was associated with activation of caspase-3, caspase-8, caspase-9. Caspase-8 inhibition prevented the activation of both caspase-3 and caspase-9. In addition, cisplatin-induced apoptosis increased the expression of Bax, but not the level of Bcl-2. These change of Bax/bcl-2 ratio caused the release of cytochrome c from mitochondria into cytosol. In previous study, the ethanol extract of Bojungbangam-tang (EBJT) inhibited cisplatin-induced apoptosis in rat mesangial cells through inhibition of ERK and JNK activation. However, EBJT did not increase cell proliferation, because it did not prevent cisplatin-induced G2/M phase arrest. These effect of EBJT may be related to p38 activation. Cisplatin-induced G2/M phase arrest are inhibited by treatment with p38 inhibitor and EBJT in rat mesangial cells. Also, p38 inhibition and EBJT treatment on cisplatin-induced G2/M phase arrest are markedly increased the G0/G1 phase and reduced the sub-G1. In conclusion, anti-apoptotic effet of EBJT did not increases cell proliferation, because EBJT did not reduce p38 activation related to cisplatin-induced G2/M phase arrest.