• Journal of Ginseng Research
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• v.41 no.1
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• pp.96-102
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• 2017

Background: Korean ginseng, Panax ginseng Meyer, has been used as a traditional oriental medicine to treat illness and promote health for several thousand years. Ginsenosides are the main constituents for the pharmacological effects of P. ginseng. Since several ginsenosides, including ginsenoside (G)-Rg3 and G-Rp1, have reported antiplatelet activity, here we investigate the ability of G-Rp4 to modulate adenosine diphosphate (ADP)-induced platelet aggregation. The ginsenoside Rp4, a similar chemical structure of G-Rp1, was prepared from G-Rg1 by chemical modification. Methods: To examine the effects of G-Rp4 on platelet activation, we performed several experiments, including antiplatelet ability, the modulation of intracellular calcium concentration, and P-selectin expression. In addition, we examined the activation of integrin ${\alpha}IIb{\beta}_3$ and the phosphorylation of signaling molecules using fibrinogen binding assay and immunoblotting in rat washed platelets. Results: G-Rp4 inhibited ADP-induced platelet aggregation in a dose-dependent manner. We found that G-Rp4 decreased calcium mobilization and P-selectin expression in ADP-activated platelets. Moreover, fibrinogen binding to integrin ${\alpha}IIb{\beta}_3$ by ADP was attenuated in G-Rp4-treated platelets. G-Rp4 significantly attenuated phosphorylation of extracellular signal-regulated protein kinases 1 and 2, p38, and c-Jun N-terminal kinase, as well as protein kinase B, phosphatidylinositol 3-kinase, and phospholipase C-${\gamma}$ phosphorylations. Conclusion: G-Rp4 significantly inhibited ADP-induced platelet aggregation and this is mediated via modulating the intracellular signaling molecules. These results indicate that G-Rp4 could be a potential candidate as a therapeutic agent against platelet-related cardiovascular diseases.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.3
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• pp.175-179
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• 2018

Humic substances that can be obtained from coal resources such as leonardite in a bulk scale have been employed as crop stimulators and soil conditioners. The polymeric organics containing a variety of aromatic and aliphatic structures are known to activate plants in a multifunctional way, thus resulting in enhanced germination rate and abiotic stress resistance concomitant with induction of numerous genes and proteins. Although detailed structural-functional relationship of humic substances for plant stimulations has not been deciphered yet, cutting-edge analytical tools have unraveled critical features of humic architectures that could be linked to the action mechanisms of their plant stimulations. In this review article, we introduce key findings of humic structures and related biological functions that boost plant growth and abiotic stress resistance. Oxygen-based functional groups and plant hormone-like structures combined with labile and recalcitrant carbon backbones are believed to be critical moieties to induce plant stimulations. Some proteins such as HIGH-AFFINITY $K^+$ TRANSPORTER 1, phospholipase A2 and $H^+$-ATPase have been also recognized as key players that could be critically involved in humic substance-driven changes in plant physiology.

• International Journal of Oral Biology
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• v.33 no.1
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• pp.13-23
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• 2008

Taste is a critically important sense for the survival of an organism. However, structure and distribution of taste receptors were only recently investigated. Although expression of the ion channels responsible for the sense of salty taste and acidity was observed in the non-taste cells, receptors for sweet and bitter taste were only identified in taste cells. Salivary glands are involved in the sensing of taste and plays important roles in the transduction of taste. The purpose of this study is to examine whether taste receptors are present in the salivary glands and to provide clues for the investigation of the taste-salivary glands interaction. Using microarray and RT-PCR analyses, the presence of taste receptor mRNAs in the rat von Ebner gland and submandibular gland was confirmed. Type I taste receptors were preferentially expressed in von Ebner gland, whereas type II taste receptors were expressed in both von Ebner gland and submandibular gland. The tastespecific signal tranducing proteins, $G_{\alpha}gustducin$ and phospholipase C ${\beta}2$, were also detected in both salivary glands by immunohistochemistry. Finally, the activation of the calcium signal in response to bitter taste in the acinar cells was also observed. Taken together, these results suggest that taste receptors are present in the von Ebner gland and submandibular gland and that type II taste receptors are functionally active in both salivary glands.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.18
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• pp.8377-8382
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• 2016

Background: The aim of this study was to evaluate any association between a single nucleotide polymorphism (SNP) in the patatin-like phospholipase domain containing 3 (PNPLA3) (rs738409, C>G) and the development and prognosis in patients with hepatocellular carcinoma (HCC). Materials and Methods: Two hundred heathy controls and 388 HCC cases were included: 211 with HBV, 98 patients with HCV, 29 with alcoholic steatohepatitis (ASH) and 52 with non-alcoholic steatohepatitis (NASH). The SNP was determined by real-time PCR based on TaqMan assays. Results: The prevalence of rs738409 genotypes CC, CG and GG in controls was 91 (45.5%), 88 (44.0%), and 21 (10.5%), respectively, while the corresponding genotypes in all patients with HCC was 158 (40.7%), 178 (45.9%), and 52 (13.4%). The GG genotype had significantly higher distribution in patients with ASH/NASH-related HCC compared with controls (OR=2.34, 95% CI=1.16-4.71, P=0.018), and viral-related HCC cases (OR=2.15, 95% CI=1.13-4.08, P=0.020). However, the frequency of the GG genotype was similar between controls and patients with viral-related HCC. At initial diagnosis, HBV-related HCC were larger and at more advanced BCLC stage than the other HCC groups. There were no significant differences between the GG and non-GG groups regarding clinical characteristics, tumor stage and overall survival. Conclusions: These data suggest an influence of the PNPLA3 polymorphism on the occurrence of HCC in patients with ASH/NASH but not among those with chronic viral hepatitis. However, the polymorphism was not associated with the prognosis of HCC.

• Journal of Embryo Transfer
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• v.32 no.4
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• pp.275-285
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• 2017

Lysophosphatidic acid (LPA) is an important signaling molecule. Here, the effect and mechanism of LPA on the preimplantation development of porcine embryos during in vitro culture (IVC) was examined. Porcine embryos were cultured in porcine zygote medium (PZM-3) supplemented with $30{\mu}M$ LPA during different days. There was a significantly higher cleavage rate in Day 1-7 and significantly higher total cell number of blastocysts in Day 1-3 and Day 4-7. It was also found that messenger RNA (mRNA) expression level of PCNA, BCL2 and BAX in blastocysts obtained from D1-7 group were significantly higher and BCL2/BAX mRNA ratio in D1-3 group was significantly lower than control group but Day 4-7 and Day 1-7 groups were comparable with control group. Treatment with $20{\mu}M$ PLC inhibitor significantly decreased the embryo cleavage rate and blastocyst formation rate. Moreover, LPA as an activator of PLCs, enhanced the $30{\mu}M$ LPA + $20{\mu}M$ U73122 group embryo cleavage rate which similar with control group. In conclusion, the results suggest that treatment with LPA during IVC improves the porcine early embryo cleavage by activation of PLC signaling pathway and regulate the mRNA expression that contribute to total cell number of blastocysts during blastocyst formation.

• Molecules and Cells
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• v.19 no.1
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• pp.60-66
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• 2005

Low density lipoproteins (LDL) play important roles in the pathogenesis of atherosclerosis. Diabetes is associated with accelerated atherosclerosis leading to cardiovascular disease in diabetic patients. Although LDL stimulates the proliferation of arterial smooth muscle cells (SMC), the mechanisms are not fully understood. We examined the effects of native LDL and glycated LDL on the extracellular signal-regulated kinase (ERK) pathway. Addition of native and glycated LDL to rat aorta SMCs (RASMCs) stimulated ERK phosphorylation. ERK phosphorylation was not affected by exposure to the $Ca^{2+}$ chelator BAPTA-AM but inhibition of protein kinase C (PKC) with GF109203X, inhibition of Src kinase with PP1 ($5{\mu}M$) and inhibition of phospholipase C (PLC) with U73122/U73343 ($5{\mu}M$) all reduced ERK phosphorylation in response to glycated LDL. In addition, pretreatment of the RASMCs with a cell-permeable mitogen-activated protein kinase kinase (MEK) inhibitor (PD98059, $5{\mu}M$) markedly decreased ERK phosphorylation in response to native and glycated LDL. These findings indicate that ERK phosphorylation in response to glycated LDL involves the activation of PKC, PLC, and MEK, but is independent of intracellular $Ca^{2+}$.

• The Korean Journal of Physiology and Pharmacology
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• v.15 no.1
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• pp.61-66
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• 2011

P2Y receptors are metabotropic G-protein-coupled receptors, which are involved in many important biologic functions in the central nervous system including retina. Subtypes of P2Y receptors in retinal tissue vary according to the species and the cell types. We examined the molecular and pharmacologic profiles of P2Y purinoceptors in retinoblastoma cell, which has not been identified yet. To achieve this goal, we used $Ca^{2+}$ imaging technique and western blot analysis in WERI-Rb-1 cell, a human retinoblastoma cell line. ATP ($10\;{\mu}M$) elicited strong but transient $[Ca^{2+}]_i$ increase in a concentration dependent manner from more than 80% of the WERI-Rb-1 cells (n=46). Orders of potency of P2Y agonists in evoking $[Ca^{2+}]_i$ transients were 2MeS-ATP>ATP>>UTP=${\alpha}{\beta}$-MeATP, which was compatible with the subclass of $P2Y_1$ receptor. The $[Ca^{2+}]_i$ transients evoked by applications of 2MeS-ATP and/or ATP were also profoundly suppressed in the presence of $P2Y_1$ selective blocker (MRS 2179; $30\;{\mu}M$). $P2Y_1$ receptor expression in WERI-Rb-1 cells was also identified by using western blot. Taken together, $P2Y_1$ receptor is mainly expressed in a retinoblastoma cell, which elicits $Ca^{2+}$ release from internal $Ca^{2+}$ storage sites via the phospholipase C-mediated pathway. $P2Y_1$ receptor activation in retinoblastoma cell could be a useful model to investigate the role of purinergic $[Ca^{2+}]_i$ signaling in neural tissue as well as to find a novel therapeutic target to this lethal cancer.

• BMB Reports
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• v.35 no.4
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• pp.395-402
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• 2002

Caveolae are small, flask-shaped, non-clathrin coated invaginations of the plasma membrane of many mammalian cells. Caveolae have a coat that includes caveolin. They have been implicated in numerous cellular processes, including potocytosis. Since the human folate receptor (hFR) and other glycosyl-phosphatidylinositol (GPI)-tailed proteins have been co-localized to caveolae, we studied the caveolin role in the hFR function by transfecting hFR and/or caveolin cDNA into Fischer rat thyroid epithelial (FRT) cells that normally do not express detectable levels of either protein. We isolated and characterized stable clones as follows: they express (1) high levels of caveolin alone, (2) hFR and caveolin, or (3) hFR alone. We discovered that hFR is correctly processed, sorted, and anchored by a GPI tail to the plasma membrane in FRT cells. No difference in the total folic acid binding or cell surface folic acid binding activity were found between the FRT cells that were transfected with hFR, or cells that were transfected with hFR and caveolin. The hFR that was expressed on the cell surface of clones that were transfected with hFR was also sensitive to phosphatidylinositol-specific phospholipase C (PI-PLC) release, and incorporated radiolabeled ethanolamine that supports the attachment of a GPI-tail on hFR. We conclude that the processing, sorting, and function of hFR is independent on the caveolin expression in FRT cells.

• Biomedical Science Letters
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• v.12 no.3
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• pp.145-151
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• 2006

Leukotactin-l (Lkn-l )/CCL15 has been known as a potent chemoattractant of leukocytes. However, the precise function of Lkn-l in human neutrophils has not been explained well. In the present study, we investigated the contribution of Lkn-1 in chemotactic activity of human neutrophils. Both CCR1 and CCR3 mRNA expressions are strongly expressed in human neutrophils but CCR2 protein expression was uniquely detected on the cell surface. Lkn-l binding to CCR1 and CCR3 induced chemotactic activity of neutrophils. Chemotactic index of Lkn-l was comparable to that of IL-8. $MIP-1{\alpha}/CCL3$ binding to CCR1 and CCR5 has no effect on neutrophil migration. Cell migration, in response to Lkn-l, was blocked by pertussis toxin (Ptx), a $G_o/G_i$ protein inhibitor, and U73122, a phospholipase C(PLC) inhibitor but not by protein kinase C inhibitor such as rottlerin, and Ro-31-8425. Taken together, our results demonstrate that Lkn-l transduces the chemotaxis signal through $G_o/G_i$ protein and PLC. This finding provides the molecular mechanism by which Lkn-l may contribute to neutrophil movement into the site of inflammation.

• Biomedical Science Letters
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• v.13 no.4
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• pp.279-285
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• 2007

Although retinoic acid has been known as either anti-inflammatory or pro-inflammatory molecule, depending on the cell type, its exact role in mature human neutrophils has not been fully explored. In this study, we investigate the effects of retinoic acid on neutrophil apoptosis and the associated mechanism and found that 9-cis retinoic acid (9CRA) significantly inhibits the spontaneous apoptosis of neutrophils. Its effect is increased by co-treatment with $TNF-\alpha$ (P<0.05). The 9CRA-induced inhibition is blocked by the following enzyme inhibitors: Ly 294002, phosphoinoside (PI)-3 kinase inhibitor, U73122, a phospholipase C (PLC) inhibitor, PP2, Src family protein inhibitor, SB202190, p38 MAPK inhibitor, and BAY-11-7085, NF-kB inhibitor. This study also demonstrates that all-trans retinoic acid suppresses spontaneous apoptosis, similar to the mechanism of inhibition exhibited by 9CRA. Phosphorylation of p38 MAPK decreases by 9CRA treatment. $Ik-B{\alpha}$ is degraded until 30 minutes after a time-dependent 9CRA treatment, but degradation can be inhibited by Ly 294002. These results indicate that 9CRA decreases p38 MAPK activation, induces NF-kB activation via PI-3 kinase, and also blocks cleavage of caspase 3. As these findings suggest, 9CRA has a molecular mechanism which may help pro-inflammatory response by blocking neutrophil apoptosis.